A Mechanistic Pathway from Post-Viral Stress to ME/CFS Persistence

Abstract

Background. Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) and related post-viral conditions are characterized by post-exertional malaise (PEM), delayed symptom worsening, and failure to return to baseline despite rest. While many biological abnormalities have been described, a unifying explanation for persistence—rather than symptom generation alone—has remained elusive.

Core mechanism. This document presents a timing-first, recovery-phase model (GLA v2.7) in which illness persists when stress signals fail to terminate cleanly. Impaired signal resolution produces residual “tails” that overlap into recovery, converting recovery itself into a stress-bearing phase. Repeated non-closure leads to biological encoding of unresolved recovery duration (Resolution Duration Memory, RDM), with adipose tissue acting as a dominant slow reservoir.

Persistence and severity. Once RDM is established, downstream circulatory outputs—particularly red-blood-cell–derived extracellular vesicles (RBC-EVs)—amplify symptoms in a clearance-dependent manner. Liver–spleen clearance bandwidth becomes rate-limiting; delayed decay of stress signals reinforces endothelial, autonomic, and immune instability, producing a self-sustaining loop that no longer depends on the original trigger.

Unifying features. The framework integrates skeletal muscle and endothelium as execution surfaces where failure becomes visible, ER–mitochondrial calcium mis-timing as a termination substrate, SMPDL3B membrane-brake failure (shedding or deficient states) as a permissive trunk-level change, and genetic variation as a modifier of recovery tolerance rather than disease initiation.

Scope. This is a mechanistic synthesis, not a diagnostic or treatment guide. It does not require ongoing infection, cytokine storms, or psychogenic causation, and it does not claim that all ME/CFS arises from a single trigger. Its purpose is to explain how failed recovery becomes self-sustaining and why PEM is delayed, cumulative, and resistant to rest once persistence is established.

Introduction

Myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) is increasingly recognized as a disorder of persistent physiological instability rather than a static deficit or a continuously active disease process. While symptoms may fluctuate, worsen after exertion, or improve transiently with rest, the defining problem is not the inability to respond to stress, but the inability to fully recover once stress has passed.

This document presents a mechanistic pathway by which a post-viral state—most clearly illustrated by Long COVID—can transition into a self-sustaining ME/CFS-like persistence state. The focus is not on diagnosis or symptom cataloging, but on how failed recovery becomes biologically encoded, allowing illness to persist even when the original trigger has diminished or resolved.

Within the GLA v2.7 framework, stressors such as infection, physical exertion, orthostatic challenge, cognitive or emotional load, and environmental strain are treated as coordination demands, not as direct sources of damage. Under normal conditions, these demands are followed by clean signal termination and recovery. Persistence arises when termination fails and recovery does not fully close.

The critical failure is therefore timing-first. Persistent peripheral input increases termination pressure, while state-dependent control noise lowers closure probability and prolongs recovery processes. Residual activity then overlaps into periods that should be quiescent, converting recovery into an active, stress-bearing phase. When this pattern repeats, unresolved recovery duration accumulates and becomes biologically remembered.

Post-exertional malaise (PEM) is a key clinical expression of this failure, but it is not the root cause. PEM reflects recovery-phase collapse in tissues such as skeletal muscle and endothelium, where timing errors in perfusion, redox control, and calcium handling are amplified. The same recovery failure logic, however, also explains cognitive, autonomic, and multisystem symptoms that persist even in the absence of overt exertion.

The sections that follow establish the v2.7 framework updates, define the roles of persistent input, the Signal Resolution Layer (SRL), recovery-phase execution stress, Resolution Duration Memory (RDM), circulatory and clearance amplifiers, and then trace the full mechanistic sequence by which post-viral stress transitions into self-sustaining ME/CFS persistence.

Figure 1 — Post-Viral Persistence Spine (GLA v2.7)

Glossary — Core GLA v2.7 Terms

Signal Resolution Layer (SRL)

Definition. The Signal Resolution Layer (SRL) is the physiological control layer responsible for terminating stress and immune signaling once the initiating threat has passed. Its function is not to reduce signal strength, but to enforce correct timing, withdrawal, and separation of signaling events across autonomic, immune, endothelial, and metabolic systems.

Key properties.
Governs onset–offset precision, not activation magnitude.
Coordinates termination across autonomic tone (sympathetic → parasympathetic withdrawal), neuroendocrine signals (catecholamines, glucocorticoids), and endothelial and immune signaling.
Failure presents as temporal overlap, not hyperinflammation.

Canonical clarification. SRL failure means signals that should have ended remain temporally active, even at low amplitude.

SRL Tail Persistence

Definition. SRL tail persistence refers to the continued presence of unresolved signaling activity after the initiating stressor has ended, caused by impaired signal termination rather than ongoing threat or stimulation.

What an SRL “tail” is.
A residual signaling duration, not a new signal.
Often low-grade, diffuse, and difficult to measure at baseline.
Becomes harmful through overlap with subsequent demands.

Mechanistic consequences.
Increases coordination debt across systems.
Forces recovery processes (ER–MAM Ca²⁺ handling, redox reset, perfusion normalization) to operate under noise.
Raises the probability that recovery fails even at low exertion.

Canonical framing. PEM is not caused by exertion exceeding capacity, but by exertion overlapping with unresolved SRL tails.

Resolution Duration Memory (RDM)

Definition. Resolution Duration Memory (RDM) is the biological encoding of unresolved stress duration, whereby tissues retain information that prior stress did not properly resolve, biasing future responses toward prolonged or defensive states.

What RDM is not.
Not memory of the original pathogen.
Not continuous inflammation.
Not permanent tissue damage.

Where RDM resides.
Encoded primarily in immune and stromal cells, not parenchymal cells.
In this framework, adipose tissue is a dominant RDM reservoir due to large immune cell populations, endocrine coupling, and slow turnover and clearance.

Functional effect. Lowers thresholds for future SRL tail persistence and makes PEM self-sustaining, no longer requiring the original trigger.

Canonical transition point. ME/CFS becomes self-sustaining once RDM is established, not when symptoms first appear.

Clearance Bandwidth

Definition. Clearance bandwidth is the maximum rate at which the body can safely remove stress-associated biological byproducts—including damaged cells, extracellular vesicles (EVs), oxidized lipids, and signaling debris—without generating secondary stress signals.

Primary clearance organs.
Liver (Kupffer cells, hepatocytes), spleen, and the reticuloendothelial system.

Why bandwidth matters.
Clearance is rate-limited.
Exceeding bandwidth does not increase clearance speed.
Instead, it produces persistent danger signals.

In ME/CFS.
Elevated EV load plus RBC damage leads to clearance saturation.
Saturation sustains immune and endothelial noise, which feeds back into RDM encoding.

Canonical rule. Severity in ME/CFS correlates more strongly with clearance overload than with upstream injury magnitude.

One-line map.
Persistent input → SRL tail persistence → failed recovery → RDM encoding (adipose) → amplified stress outputs → clearance bandwidth saturation → sustained signals → reinforced RDM.

1. Post-Viral Stress as a Persistent Input State

Long COVID (LC) is increasingly understood not as a single ongoing inflammatory process, but as a condition sustained by persistent peripheral inputs that repeatedly engage immune, vascular, and neural systems even after acute infection has resolved clinically [3] [4]. Among these inputs, gut microbiome dysregulation and intestinal barrier compromise represent one of the most consistently supported and mechanistically coherent drivers [1] [5].

This section summarizes the established gut-centered biology of Long COVID, without invoking ME/CFS persistence mechanisms or downstream control failure.

1.1 Gut microbiome dysregulation after SARS-CoV-2 (Established)

Enteric infection and ACE2 disruption

Although SARS-CoV-2 is classically described as a respiratory virus, intestinal epithelial cells (enterocytes) express high levels of ACE2 and relevant proteases, making direct gut involvement biologically plausible and experimentally supported. Acute gastrointestinal symptoms are common during infection, and viral RNA and protein have been detected in intestinal tissue well after respiratory clearance in a subset of patients [1].

Beyond viral entry, ACE2 plays a homeostatic role in intestinal epithelial metabolism. SARS-CoV-2–associated ACE2 downregulation reduces surface expression of the B0AT1/SLC6A19 transporter, impairing tryptophan absorption by enterocytes. This has downstream consequences for epithelial metabolic signaling rather than simply reducing nutrient availability [1].

Loss of epithelial antimicrobial support

Reduced tryptophan uptake alters mTOR-dependent epithelial programs that normally sustain antimicrobial peptide production. As antimicrobial tone falls, the competitive balance of the gut microbiota shifts—not through acute inflammation, but through loss of epithelial containment and regulation. This links ACE2 disruption directly to microbiome instability without requiring immune hyperactivation [1].

Microbiome dysbiosis and SCFA depletion

Longitudinal studies in LC cohorts demonstrate persistent dysbiosis compared to individuals who recover fully after acute COVID-19 [5]. Characteristic findings include:

• Reduced abundance of short-chain fatty-acid (SCFA)–producing taxa
• Lower butyrate levels
• Expansion of pro-inflammatory or opportunistic organisms

SCFAs—particularly butyrate—normally support epithelial barrier integrity and immunoregulatory signaling. Their depletion weakens these functions, biasing the gut toward instability rather than overt inflammation [1] [5].

1.2 Barrier dysfunction and microbial translocation

As epithelial support erodes and mucosal immune balance shifts, tight-junction integrity deteriorates. Disruption of claudins, occludins, and ZO-1 increases intestinal permeability, allowing microbial products to cross into systemic circulation. LC cohorts show elevated markers consistent with this process, including zonulin, lipopolysaccharide-binding protein (LBP), β-glucan, and soluble CD14—consistent with ongoing microbial translocation and innate immune engagement [1].

Importantly, this process does not require high cytokine levels or continuous acute inflammation. Instead, low-grade, repeatedly renewed exposure to microbial products engages pattern-recognition receptors (PRRs) on myeloid and endothelial cells, sustaining immune signaling demands over time [1].

1.3 Functional consequence: a chronic peripheral input, not a cytokine storm

Taken together, these findings support a coherent interpretation of the gut in Long COVID as a persistent input source, characterized by:

• Ongoing antigenic and microbial signaling
• Recurrent PRR engagement
• Barrier-derived uncertainty rather than acute immune escalation

The result is a chronic, noisy peripheral immune input that repeatedly re-engages systemic signaling pathways—even when traditional inflammatory markers fluctuate or normalize [4] [1].

Transition: Section 1 → Section 2.
A system exposed to persistent peripheral input must repeatedly decide whether it is safe to disengage; the next section examines how chronic gut-derived immune and neural signaling in Long COVID can interfere with signal termination, increasing the likelihood of unresolved recovery states even in the absence of overt inflammation.

2. From Persistent Input to Impaired Termination

A system exposed to continuous or repeatedly renewed peripheral input must repeatedly determine when it is safe to disengage and return to baseline. In Long COVID, gut-derived immune and neural signals do not typically present as high-amplitude inflammatory spikes, but as low-grade, temporally persistent cues that arrive before prior signaling has fully resolved [4] [1]. Under these conditions, the primary challenge is not excessive activation, but impaired termination—the failure of signaling programs to end cleanly once the initiating demand has passed [6]. This section examines how sustained gut-origin input can bias autonomic, endothelial, and immune control layers toward prolonged “still-active” states, increasing the likelihood that recovery processes remain partially engaged rather than fully completing.

Early immune signals anticipate persistence but do not maintain it

Longitudinal immune profiling demonstrates that post-acute COVID-19 sequelae are anticipated early by viral, immune, and metabolic factors, including RNAemia, EBV reactivation, autoantibodies, and metabolic state. However, these signals weaken or decouple over time even as symptoms persist [4]. This indicates that early immune activation predicts risk but does not itself store or maintain illness duration. Within GLA v2.7, these findings support the distinction between persistent input and self-sustaining persistence, motivating the need for a downstream duration-encoding mechanism beyond immune activation alone [4].

2.1 Norepinephrine Persistence and SRL Tail Overlap

Under normal conditions, norepinephrine (NE) functions as a precision timing signal, coordinating rapid state transitions across autonomic, vascular, and immune interfaces. NE release is expected during cognitive load, orthostatic challenge, emotional salience, or illness—but critically, it is also expected to terminate cleanly once coordination demand has passed. Proper termination depends on rapid reuptake, enzymatic clearance, receptor desensitization, and timely opposition by parasympathetic and endothelial braking systems [7].

In Long COVID, accumulating evidence suggests that this termination precision is degraded, even when NE release itself is appropriate. Rather than shutting off fully, residual adrenergic tone persists into the recovery window, leaving coordination signals partially active during periods that should be quiescent. This does not require elevated circulating catecholamine levels and should not be interpreted as “sympathetic overdrive.” Instead, it reflects incomplete signal resolution at the Signal Resolution Layer (SRL) [7] [6].

When residual NE overlaps temporally with recovery, the system enters a state of SRL tail persistence. In this state, the initiating stressor has ended, but downstream systems continue to behave as if coordination is still required. Attempt rates remain non-zero, slow-mode resolution dominates, and recovery processes fail to complete cleanly before the next perturbation arrives. Importantly, this overlap can occur under low-amplitude, everyday demands—cognitive effort, standing, sensory load—without producing acute inflammatory or metabolic signatures [7] [4].

Functionally, persistent NE biases multiple termination-sensitive interfaces at once:

• Autonomic timing, by delaying parasympathetic re-engagement and baroreflex closure [S9] [S11].
• Endothelial control, by maintaining a “distribution-on” vascular state and degrading shear-decoding precision [7].
• Immune readiness, by prolonging low-level vigilance signals without overt cytokine escalation [6].

The result is not ongoing activation, but failure to disengage. Each episode leaves behind a small, unresolved recovery tail. When such tails recur before full resolution, they begin to overlap and accumulate, increasing the likelihood that recovery remains incomplete even in the absence of new external stress [7].

2.2 From SRL Tail Persistence to Recovery-Phase Tissue Stress

When SRL tail persistence is present, recovery no longer functions as a passive return to baseline. Instead, recovery itself becomes an active, stress-bearing phase, shaped by residual coordination signals that should have already terminated. Although the initiating stimulus has ended, low-level norepinephrine and autonomic timing noise continue to bias vascular, metabolic, and cellular behavior during what should be a quiescent window [7] [S9].

This shift is most consequential in tissues that normally experience large, rapid transitions between high demand and rest, particularly skeletal muscle and the microvascular endothelium. In these tissues, recovery requires precise disengagement: redistribution of flow, withdrawal of adrenergic tone, normalization of shear patterns, and orderly resolution of intracellular signaling. SRL tail persistence interferes with this process by keeping termination-sensitive systems partially engaged [7].

A central consequence is recovery-phase flow mismatch rather than delivery failure. Residual adrenergic signaling maintains a “distribution-on” vascular state in which total blood flow may be adequate, yet microvascular perfusion remains heterogeneous relative to true metabolic demand. Shear stress therefore fluctuates instead of settling, creating small but repeated hypoxia–reperfusion and redox stress cycles during recovery. These effects arise from timing and localization errors, not from sustained vasoconstriction or global hypoperfusion [7].

At the cellular level, this flow and signaling mismatch propagates into ER–mitochondrial recovery processes. Calcium reuptake, redox reset, and membrane repair are all termination-dependent operations. When disengagement is delayed, calcium exposure persists longer than intended, redox signaling remains partially active, and recovery becomes metabolically costly rather than restorative. Importantly, this does not require overt ischemia, inflammation, or structural injury; it reflects kinetic failure of shutdown, not excess load [18].

Because these stresses emerge during recovery rather than exertion, symptoms are delayed and often counterintuitive. Activity may appear tolerated in the moment, while injury is encoded later as unresolved recovery work accumulates. Each episode leaves behind a small amount of incompletely resolved coordination demand. When subsequent demands arrive before full resolution, these recovery-phase stresses overlap and compound, increasing the probability that recovery remains incomplete even under modest load [18].

At this stage, the system is still partially input-dependent: reducing demand, extending rest, or lowering autonomic activation can permit partial recovery. However, a qualitative transition has already occurred. Stress is no longer confined to external triggers; it is now being generated internally during recovery by failure of termination itself. This marks the final point at which persistence is not yet self-sustaining and sets the stage for engagement of longer-term stabilization mechanisms.

2.3 ER–MAM calcium mis-timing as a driver of persistent innate immune overlap at endothelial surfaces

Within GLA v2.7, endothelial senescence is not treated as a purely cell-autonomous fate, but as the surface expression of a deeper failure in signal termination. A key upstream contributor to this failure is persistent ER–mitochondrial (ER–MAM) calcium mis-timing, which sustains low-grade innate immune signaling overlaps at endothelial interfaces even in the absence of overt inflammation or high circulating cytokines [H2] [18].

Repeated recovery-phase stress, redox imbalance, and impaired termination destabilize calcium handling at ER–MAM junctions. Instead of tightly gated release followed by full reuptake, calcium remains intermittently elevated in microdomains, particularly at endothelial surfaces where ER, mitochondria, and plasma-membrane signaling converge [S13] [S14]. This produces several compounding effects that stabilize the endothelial persistence phenotype described by Nunes et al. [H2].

Persistent innate immune signaling modes sustained by Ca²⁺ mis-timing

1. Type I interferon and antiviral program priming. Calcium-dependent regulation of interferon signaling fails to fully disengage. Rather than sustained interferon elevation, endothelial cells remain in a sub-threshold antiviral transcriptional state, with incomplete shutdown of interferon-stimulated gene (ISG) expression [H2].
2. Inflammasome readiness without full activation. ER–MAM calcium mis-timing maintains inflammasome priming (e.g. NLRP3 readiness) without consistent inflammasome assembly or cytokine release [H2].
3. Stress-kinase and NF-κB overlap. Calcium-sensitive stress kinases and NF-κB signaling fail to terminate cleanly; instead of discrete activation–resolution cycles, endothelial cells exhibit temporal overlap of stress-response signaling, sustaining SASP-like transcription without inflammatory escalation [H2].

Endothelial consequences of persistent Ca²⁺-driven immune overlap

• Endothelial cells adopt a “not-resolved” signaling state. Persistent calcium microdomain activity stabilizes SASP-like programs—pro-oxidative, pro-coagulant, vasoactive, and barrier-disruptive—without requiring ongoing viral presence [H2].
• Barrier and vasomotor regulation remain unstable. Calcium mis-timing disrupts endothelial nitric-oxide synthase coordination and impairs junctional integrity; the pathology is therefore one of NO timing and localization failure, not simple NO deficiency [H2] [18].
• Immune clearance becomes progressively impaired. Calcium-dependent mitochondrial dysfunction in endothelial and immune cells degrades antigen presentation and cytotoxic precision, reinforcing clearance failure loops that allow pathological endothelial states to persist [H2].

Integrated interpretation. In this framing, endothelial senescence represents a stabilized endpoint of unresolved calcium-mediated signaling, not merely a consequence of viral injury or immune dysfunction. ER–MAM calcium mis-timing provides a mechanistic link between recovery-phase stress (muscle, shear, redox), persistent innate immune signaling overlaps (SRL tail persistence), endothelial SASP maintenance, and clearance-limited chronicity [H2] [18].

Figure 2 — SRL Tail Persistence & Recovery-Phase Stress

3. Muscle as the Execution Surface

3.0 Why skeletal muscle is where failure becomes visible

Once persistent input and impaired termination are established (Sections 1–2), tissue-level consequences do not emerge uniformly across the body. Instead, failure becomes most apparent in skeletal muscle, which functions as the primary execution surface where upstream control instability is converted into physiological injury [8] [9].

Skeletal muscle is uniquely exposed because it combines:

• the largest dynamic perfusion range of any organ system,
• highly localized and rapidly shifting metabolic demand, and
• strong dependence on precise microvascular timing and flow distribution, rather than on total blood flow alone [10] [11].

As a result, even modest errors in endothelial timing or flow topology are amplified during muscle use, particularly during the transition from exertion to recovery. This section explains how those errors manifest as shear stress, ischemia–reperfusion–like injury, and delayed post-exertional worsening [12].

3.1 Shear stress and ischemia–reperfusion–like injury in muscle

Under normal conditions, increased muscle activity raises blood flow in a tightly regulated manner. Shear stress is sensed by the endothelial surface, decoded through the glycocalyx and membrane microdomains, and translated into precisely timed vasodilation that maintains uniform capillary perfusion [10] [11].

When endothelial timing precision is impaired, this process breaks down in a topological, not scalar fashion. Total inflow may be preserved or even elevated, but flow becomes unevenly distributed across the microvasculature. Some capillary paths become over-perfused with shortened red-blood-cell transit time, while adjacent regions are under-perfused or intermittently silent [12].

In skeletal muscle, this produces a physiological pattern analogous to micro-scale ischemia–reperfusion:

• transient local under-delivery of oxygen during contraction,
• followed by re-exposure to oxygenated blood during recovery,
• without global hypoxia or cardiac limitation.

This pattern preferentially generates oxidative stress, calcium dysregulation, and endothelial irritation during recovery rather than during exertion itself. Importantly, these effects can occur even when exertion feels tolerable at the time, because the injury mechanism is encoded during load and expressed during recovery [8] [9].

3.2 Why PEM emerges after exertion, not during it

A defining feature of ME/CFS is that symptoms peak hours to days after activity, rather than at the moment of exertion. Within this framework, that delay is not paradoxical — it is expected [8].

During exertion, skeletal muscle can often maintain output through compensatory mechanisms:

• increased glycolytic contribution,
• heightened calcium influx to sustain contraction,
• autonomic adjustments that temporarily stabilize perfusion.

These responses create a false-OK window, in which activity appears manageable despite accumulating stress. However, they do so at the cost of increased intracellular calcium load, redox strain, and endothelial signaling noise [18].

Once exertion stops, the system must terminate signaling, normalize flow, and repair micro-injury. When termination is impaired (SRL tail persistence) and flow topology is unstable, recovery becomes the point of failure. Calcium handling deteriorates, oxidative stress amplifies, and tissue-level injury becomes biologically visible [18] [8].

Post-exertional malaise therefore reflects recovery-phase collapse, not exertional exhaustion. Skeletal muscle is where this collapse is first generated because it is the tissue most sensitive to microvascular timing errors and most capable of converting them into delayed functional impairment [9].

Bridge to Section 4.
The severity and repeatability of this muscle-level failure vary between individuals, suggesting that upstream genetic differences shape tolerance to recovery-phase stress rather than determining the trigger itself.

Figure 3 — Muscle & Endothelium as Execution Surfaces

4. Genetic Bias: Reduced Tolerance to Recovery-Phase Stress

Not all individuals exposed to persistent post-viral input transition into a self-sustaining illness state. Genetic data suggest that inter-individual differences in recovery tolerance—rather than differences in immune activation—help determine whether unresolved recovery-phase stress accumulates or resolves [19] [S2].

Large-scale genetic studies of ME/CFS and Long COVID do not identify a single causative gene. Instead, they point to polygenic enrichment across pathways that regulate signal termination, membrane integrity, lipid handling, vascular buffering, and metabolic clearance. These genes shape how much unresolved stress a system can absorb before recovery fails [S2] [S3] [S4].

4.1 What the genetics do not show

Across GWAS, metabolite GWAS, and combinatorial analyses:

• There is no evidence of a monogenic immune disorder
• No consistent enrichment of cytokine overproduction pathways
• No fixed “ME gene” that initiates disease independently of context

Instead, effect sizes are small, distributed, and state-dependent, consistent with genes that modulate control bandwidth rather than disease initiation [S2] [S3] [S4].

4.2 What the genetics do converge on

Despite methodological differences, genetic studies repeatedly implicate genes involved in four tolerance-critical domains:

1. Membrane and lipid handling (e.g., ABCA1, ABCC6, MYRF).
   These genes influence cholesterol transport, lipid-raft integrity, and long-term membrane resilience. Reduced membrane stability lowers the system’s ability to cleanly terminate signaling and repair execution surfaces after stress [S3] [S4].
2. Vascular and glycocalyx integrity (e.g., ABCC6, DDR1).
   Genes affecting extracellular matrix sensing, calcification control, and endothelial interface stability modulate sensitivity to shear stress during recovery. Reduced tolerance here amplifies microvascular mismatch during low-demand phases [S3].
3. Calcium and signal timing (e.g., CACNA1A, CACNA1D, SCGN).
   These genes regulate calcium entry, neuroendocrine coupling, and excitation–termination precision. Variants bias systems toward prolonged signaling tails rather than discrete pulses, increasing overlap between recovery windows [S3].
4. Lipid, bile acid, and nitrogen routing (e.g., NR1H3 (LXRα), CYP7B1, CPS1).
   These pathways govern post-load redistribution and clearance rather than energy production itself. Inefficiencies here increase the cost of recovery, especially under repeated stress [S4] [S3].

Crucially, these domains align with recovery-phase processes, not with acute immune defense or exertional capacity.

4.3 Genetic bias as a threshold modifier

Within the GLA framework, these genetic variants are best understood as threshold and bandwidth modifiers:

• They do not create disease on their own
• They do not dictate which virus or trigger initiates illness
• They lower the margin for error during recovery

When SRL tail persistence and recovery-phase stress (Section 2) are repeatedly encountered, individuals with reduced genetic tolerance are more likely to fail recovery before termination completes. Each incomplete recovery leaves residual work behind, increasing the probability that subsequent stressors will overlap rather than resolve [18] [19].

This explains why:

• Similar post-viral insults can lead to full recovery in some individuals and persistence in others
• Genetic signals correlate better with severity, duration, and heterogeneity than with disease presence alone
• Long COVID and ME/CFS share substantial genetic overlap while remaining distinct conditions

4.4 Transition toward persistence substrates

At this stage, the system is still not self-sustaining. Genetic bias increases vulnerability, but persistence still depends on repetition and encoding. The next section introduces the mechanism by which unresolved recovery duration becomes biologically remembered—transforming a vulnerable system into one that maintains illness even when external input diminishes.

5. Adipose Tissue Enters Resolution Duration Memory (RDM)

Up to this point, persistence remains conditional: recovery fails repeatedly, but symptoms are still dependent on ongoing input and imperfect termination. Section 5 marks the critical transition where unresolved recovery duration becomes biologically encoded, allowing symptoms to persist even when external triggers diminish.

Within the GLA framework, adipose tissue is the dominant substrate for Resolution Duration Memory (RDM) [13] [14].

5.1 Why adipose is uniquely suited to store duration

Adipose tissue is not a passive energy reservoir. In control-systems terms, visceral and stress-responsive adipose behaves as a slow integrator that:

• operates on hours–days–weeks timescales rather than minutes,
• responds preferentially to repeated recovery-phase signals rather than acute spikes,
• communicates with brainstem, liver, vasculature, and immune cells via low-amplitude, long-duration outputs [13].

This makes adipose ideally positioned to stabilize slow modes once signal termination is already compromised. Importantly, adipose does not initiate stress responses and does not require high inflammatory activity to exert system-level effects [14].

Adipose is therefore largely invisible during acute illness but highly influential during repeated, incomplete recovery.

5.2 From repeated non-closure to duration encoding

When SRL tail persistence and recovery-phase tissue stress recur (Sections 2–3), the system repeatedly fails to fully disengage. Each episode leaves behind a small amount of unresolved duration.

Adipose responds to this pattern by shifting into a memory-bearing state:

• stress and glucocorticoid exposure induce tissue-local signal recycling rather than transient signaling [S14],
• recovery-phase metabolic and endocrine cues are prolonged beyond their original trigger [S15],
• slow feedback loops bias the system toward continued readiness rather than reset [14].

This process does not require ongoing stress, infection, or inflammation. Once established, adipose replays duration, not the original stimulus. This is the defining feature of Resolution Duration Memory (RDM).

5.3 What RDM is (and what it is not)

RDM is not:

• pathogen persistence,
• ongoing immune activation,
• stored “stress” or psychological memory,
• fat mass or obesity,
• a requirement for abnormal baseline laboratory findings.

RDM is:

• biological storage of how long recovery took,
• implemented through slow endocrine, metabolic, immune, and autonomic coupling [13],
• expressed as persistent low-level signaling that prevents downstream systems from fully resetting [14].

In practical terms, RDM means the body behaves as if recovery is still incomplete—even when rest is adequate and triggers are minimized.

5.4 The shift to self-sustaining PEM

Once adipose RDM is established, post-exertional malaise (PEM) becomes self-sustaining:

• new stressors are no longer required to maintain instability,
• small perturbations interact with a pre-loaded recovery deficit,
• recovery tails lengthen even under conservative pacing,
• baseline becomes increasingly difficult to re-establish.

At this point, reducing load can still reduce harm, but it cannot erase encoded duration. The system has crossed from vulnerability into persistence.

This is the moment where Long-COVID–like recovery failure becomes ME/CFS-like chronicity in control-systems terms.

Figure 4 — Resolution Duration Memory (RDM) in Adipose

6. Circulatory & Clearance Amplifiers

Once Resolution Duration Memory (RDM) is established in adipose tissue (Section 5), the system is no longer attempting to fully reset between stressors. At this stage, circulatory processes do not initiate disease, but they can strongly amplify persistence by determining whether recovery-phase stress signals are rapidly cleared or allowed to linger. The dominant amplifiers operate through red blood cells (RBCs), extracellular vesicles (EVs), and the clearance bandwidth of the liver–spleen axis [15] [17].

6.1 Shear stress drives RBC state change and EV release

Physiological shear stress and hypoxia are normally well tolerated. However, under recovery-phase instability, repeated shear variability and redox load induce state-dependent stress in RBC membranes. Because mature RBCs lack transcriptional or repair capacity, membrane stress is handled through adaptive vesiculation— the release of RBC-derived extracellular vesicles (RBC-EVs) [15].

Key properties of this vesiculation process:

• domain-localized release at cholesterol- and sphingomyelin-enriched membrane regions,
• initial function as protective off-loading of damaged membrane patches,
• no requirement for immune activation, apoptosis, or infection.

RBC-EVs therefore represent stress outputs, not pathological triggers. Their biological impact depends entirely on what happens next—specifically, how efficiently they are routed and cleared [15].

6.2 EV routing and clearance are the decisive gate

In healthy physiology, most circulating EVs are removed rapidly. Clearance is mediated predominantly through platelet and erythrocyte “hitchhiking,” followed by macrophage uptake in the liver and spleen. This process is efficient, silent, and normally terminates EV-associated signals [S11] [15].

Crucially, circulating EV burden reflects clearance state, not production rate. Under conditions of systemic stress, altered surface identity, or competing clearance demand, clearance efficiency can fall dramatically:

• EV half-life is prolonged,
• EVs remain associated with RBCs and platelets for longer periods,
• near-wall residence time in the microvasculature increases.

Uptake or cellular association does not guarantee resolution; effective clearance-to-decay is the rate-limiting step. When clearance bandwidth is exceeded or recognition is altered, EVs persist [S12] [17].

6.3 Why persistence amplifies recovery-phase instability

Persistent RBC-EVs carry biologically active cargo—including phosphatidylserine, oxidized lipids, and hemoglobin/heme—that becomes problematic only when proximity and duration are sufficient [16].

A key amplification mechanism is nitric-oxide (NO) timing disruption. Intact RBCs normally protect endothelial NO signaling through compartmentalization and near-wall cell-free zones. By contrast, hemoglobin contained within RBC-derived microparticles reacts with NO at rates approaching cell-free hemoglobin—approximately 1000× faster than intact erythrocytes [16].

Even low but persistent microparticle burdens can therefore:

• quench NO prematurely,
• desynchronize NO release from shear sensing,
• corrupt perfusion timing during recovery.

Importantly, this represents NO timing and localization noise, not NO deficiency. The pathological effect depends on persistence and near-wall residence, not on bulk NO levels.

6.4 Clearance bandwidth sets symptom severity, not initiation

At this stage of the sequence:

• RBCs and EVs do not initiate PEM,
• they shape severity, duration, and variability by amplifying recovery-phase noise.

When clearance is efficient, RBC-EV signals decay, NO timing stabilizes, and recovery can complete. When clearance is delayed, persistent EV exposure:

• sustains endothelial and immune “not-resolved” states,
• increases the metabolic cost of repair,
• reinforces RDM encoding in adipose tissue.

This explains why ME/CFS severity correlates more strongly with clearance limitation than with exertion magnitude, inflammation level, or baseline laboratory abnormalities [17].

6.5 Positioning within the overall framework

This circulatory pathway functions as a parallel persistence amplifier:

• downstream of skeletal-muscle recovery failure (Section 3),
• upstream of symptom duration and baseline erosion,
• and fully dependent on clearance bandwidth.

It is therefore mechanistically distinct from disease initiation and from primary immune activation. Persistence emerges not because more EVs are produced, but because clearance fails to keep pace with stress-encoded outputs.

Bridge to Section 7.
Circulatory amplifiers intensify recovery-phase instability only insofar as their outputs persist. Whether RBC-derived EVs and related stress signals decay or accumulate is determined not at the execution surface, but by downstream clearance capacity. The next section examines how the liver–spleen axis becomes a rate-limiting bottleneck once clearance demand repeatedly exceeds bandwidth, converting amplification into locked persistence.

7. Clearance Bottleneck and Liver–Spleen Overload

By this stage, persistence is no longer driven by new triggers or isolated failures. Instead, symptoms are maintained by a rate-limiting clearance bottleneck in systems responsible for removing stress-encoded biological outputs. The liver–spleen axis sits at the center of this bottleneck [15] [17].

7.1 Clearance is a bandwidth-limited process

Clearance of damaged cells, red-blood-cell–derived vesicles, and circulating extracellular vesicles is not binary. It is a throughput-limited physiological service, governed by:

• Kupffer cell and splenic macrophage capacity,
• receptor-mediated recognition and uptake rates,
• intracellular processing and recycling constraints,
• competition with other clearance demands (lipids, platelets, microbial debris, apoptotic material) [S12].

Under normal conditions, this system rapidly removes RBC-EVs and other circulating stress signals. When demand exceeds capacity—even modestly but persistently—clearance slows, half-lives extend, and signals that should decay instead accumulate [15].

This bottleneck does not require liver disease, fibrosis, or abnormal liver enzymes. It reflects functional saturation, not structural failure.

7.2 How overload emerges after RDM is established

Resolution Duration Memory (RDM) in adipose tissue (Section 5) ensures that low-level recovery signaling continues even during rest. This creates a continuous background load on clearance systems.

At the same time, recovery-phase muscle stress (Section 3) and circulatory amplifiers (Section 6) intermittently increase the production of:

• RBC-derived extracellular vesicles,
• platelet–RBC–EV aggregates,
• oxidized lipid and membrane fragments.

Each episode alone is tolerable. The problem arises from overlap:

• clearance demand from one episode arrives before the previous load has been fully processed,
• Kupffer cells and splenic macrophages remain occupied,
• recognition and uptake slow further as surface receptors and intracellular processing pathways are engaged [S12].

The result is a progressive widening gap between production and clearance, even without escalation of injury or inflammation [17].

7.3 Consequences of delayed clearance

When clearance is delayed, circulating stress signals remain biologically active for longer than intended. This has several reinforcing effects:

• Endothelial timing noise persists, as RBC-EV–associated hemoglobin and lipids continue to interfere with nitric-oxide localization and shear decoding [16].
• Immune and autonomic “not-resolved” states are sustained, even without overt inflammation.
• Metabolic recovery costs increase, as tissues operate in a partially activated state.
• Adipose RDM is reinforced, because prolonged recovery signals are interpreted as evidence that resolution has not occurred [13] [14].

Critically, none of these effects require escalation. Persistence arises from duration, not intensity.

7.4 The self-sustaining loop

At this point, the system enters a closed loop:

1. Adipose RDM maintains low-level recovery signaling,
2. recovery-phase tissue stress and shear variability continue to generate RBC-EVs,
3. clearance systems operate near or beyond bandwidth,
4. EV persistence amplifies endothelial and autonomic instability,
5. prolonged instability further encodes RDM.

The loop no longer depends on the original viral insult. Long COVID has transitioned into ME/CFS-like persistence as a systems-level control failure.

7.5 Guardrail clarification

This clearance bottleneck:

• does not imply primary liver disease,
• does not require ongoing infection,
• does not make RBCs or EVs disease initiators.

Instead, it explains why symptom severity tracks clearance capacity, why recovery becomes unreliable, and why removing triggers alone is often insufficient once persistence is established [17].

Bridge to Section 8.
Together, impaired termination, recovery-phase tissue stress, genetic recovery tolerance, adipose RDM, and clearance bottlenecks form a self-reinforcing system; the final section summarizes this sequence and outlines testable predictions that distinguish persistence mechanisms from initiating events.

Figure 6 — Clearance Bottleneck & Self-Sustaining Loop

8. Integrated Summary and Testable Predictions

8.1 Integrated mechanistic summary

This page has traced a continuous mechanistic sequence from post-viral disruption to self-sustaining ME/CFS–like persistence, without requiring ongoing infection or escalating inflammation.

• Long COVID establishes a persistent input state.
  Gut dysbiosis and barrier dysfunction generate chronic, low-grade peripheral signaling rather than a cytokine storm (Section 1) [1] [4].
• Signal termination becomes unreliable.
  Persistent input degrades norepinephrine termination and autonomic precision, producing SRL tail persistence—temporal overlap of unresolved signaling (Section 2) [6] [7].
• Recovery, not exertion, becomes the failure point.
  In skeletal muscle and endothelium, impaired termination converts flow-timing errors into shear stress and ischemia–reperfusion–like injury during recovery (Section 3) [8] [9].
• Genetic background modulates recovery tolerance.
  Polygenic variation narrows recovery bandwidth, determining how much unresolved stress can be absorbed before failure repeats (Section 4) [18] [19].
• Duration becomes biologically encoded.
  Repeated non-closure stabilizes as Resolution Duration Memory (RDM) in adipose tissue, shifting the system from vulnerability to persistence (Section 5) [13] [14].
• Circulatory outputs amplify persistence.
  Shear-stressed RBCs and EVs act as persistence amplifiers whose impact depends on clearance, not production (Section 6) [15] [16].
• Clearance bottlenecks lock the loop.
  Liver–spleen clearance bandwidth becomes rate-limiting; delayed decay of stress signals reinforces endothelial instability and further encodes RDM (Section 7) [17].

At this point, illness is self-sustaining: symptoms persist because recovery never fully resolves, not because a trigger remains active.

8.2 What this framework explicitly does not claim

• It does not claim that SARS-CoV-2 uniquely causes ME/CFS.
• It does not require ongoing viral replication or antigen persistence.
• It does not frame ME/CFS as a primary immune, mitochondrial, or hematologic disease.

Instead, it explains persistence as a control-layer and clearance-limited failure of recovery.

8.3 Testable predictions

This framework makes several specific, falsifiable predictions:

1. Termination, not load, predicts PEM.
   Interventions that improve signal termination or recovery timing (without increasing capacity) should reduce PEM even if exertional limits remain unchanged.
2. Severity tracks clearance, not inflammation.
   Measures of EV burden, RBC stress, or clearance efficiency should correlate more strongly with symptom severity and duration than with cytokine levels or resting metabolic markers.
3. Once RDM is established, trigger removal is insufficient.
   In individuals with established persistence, reducing triggers alone will lower harm but will not restore full recovery unless duration encoding is actively silenced.
4. Shear reduction outperforms energy support.
   Interventions that reduce microvascular shear variability during recovery should outperform metabolic “energy-boosting” strategies in reducing delayed PEM.
5. Clearance saturation produces delayed, not immediate effects.
   Worsening after exertion should correlate with delayed clearance dynamics (hours–days), not with immediate physiological stress during activity.

8.4 Final framing statement

In this model, ME/CFS is not sustained by what the body is reacting to, but by what the body has failed to finish resolving.

This reframing shifts the therapeutic target from suppression and compensation toward restoring termination, recovery, and clearance— the prerequisites for durable resolution.

9. Integrating Published ME/CFS Hypotheses within the GLA Framework

A large number of hypotheses have been proposed to explain the persistence and multi-system nature of myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS). While these hypotheses often emphasize different biological domains—immune signaling, autonomic control, redox metabolism, or membrane biology—they are not mutually exclusive.

Within the Gut–Liver–Autonomic (GLA) framework, these hypotheses can be constrained, positioned, and mechanistically explained as partial views of a shared control-layer failure, rather than as competing disease origins. In this section, four of the strongest and most influential hypotheses are used to demonstrate how diverse observations converge when interpreted through recovery, termination, and vascular execution stability.

The purpose of this integration is not to replace prior work, but to clarify where each hypothesis operates in the mechanistic sequence, what it explains well, and what it cannot explain on its own.

Terminology — Quick Key (GLA v2.7)

Short definitions used throughout the hypothesis integration section.

Figure 7 — Mapping Hypotheses onto the GLA Scaffold

Integration of the Wirth & Scheibenbogen Hypothesis within GLA v2.7

Within the GLA v2.7 framework, the model proposed by Wirth and Scheibenbogen is integrated as a foundational execution-surface and symptom-expression hypothesis, rather than as a complete explanation of disease persistence or chronicity. Their work provides critical evidence for where post-exertional malaise (PEM) is generated and how symptoms are expressed, particularly through skeletal muscle vulnerability, autonomic dysregulation, and vascular control abnormalities.

Wirth and Scheibenbogen also describe several self-reinforcing pathological loops relevant to ME/CFS, including calcium overload, autonomic imbalance, reduced blood volume with renin–angiotensin paradox features, and maladaptive neurovascular feedback. These mechanisms explain how exertional stress can trigger PEM and how symptoms may be maintained over time through interacting physiological instabilities.

GLA v2.7 extends this model by situating these findings within a broader control-layer and recovery-phase framework. Specifically, GLA connects execution-surface failure to upstream and downstream processes that govern duration and persistence. These include shear-stress–activated PEM, red-blood-cell–derived extracellular vesicle (RBC-EV) release with near-wall vascular persistence, nitric-oxide timing dysfunction, ER–mitochondrial (ER–MAM) calcium mis-timing, and sustained innate immune signaling at endothelial surfaces driven by calcium-dependent non-termination.

In addition, GLA incorporates loss of SMPDL3B-mediated phospholipid braking, altered lipid metabolism under maintenance throttling, and genetic validation of control-layer vulnerability rather than primary disease causation. Crucially, GLA identifies additional self-sustaining loops—most notably the RBC-EV → liver–spleen clearance bottleneck—that convert repeated recovery failure into Resolution Duration Memory (RDM) encoded in adipose tissue. This mechanism explains why ME/CFS can persist despite prolonged rest and reduced external triggers.

In summary, Wirth and Scheibenbogen provide essential evidence for execution-surface vulnerability, autonomic modulation, and symptom generation, while GLA v2.7 explains why these disturbances persist, accumulate, and become self-sustaining through recovery-phase failure, clearance limitation, and duration encoding that extend beyond calcium, autonomic, or vascular loops alone.

Mapping Wirth & Scheibenbogen mechanisms to GLA v2.7

JCSM-16-e13669

Integration of the Nunes et al. Hypothesis within GLA v2.7

Nunes et al. propose that ME/CFS and Long COVID are sustained by virus-induced endothelial senescence, perpetuated by impaired immune clearance of senescent endothelial cells. In this model, senescent endothelial cells adopt a senescence-associated secretory phenotype (SASP) that is pro-oxidative, pro-coagulant, vasoconstrictive, and barrier-disruptive, thereby producing multisystem manifestations including reduced cerebral blood flow, skeletal-muscle perfusion deficits, gastrointestinal barrier dysfunction, and post-exertional malaise (PEM). Chronicity is attributed to bidirectional reinforcement between immune dysfunction and endothelial senescence, independent of ongoing infection.

Within GLA v2.7, this hypothesis is integrated as a core execution-surface persistence amplifier, with an essential upstream clarification: endothelial senescence is stabilized by failed signal termination and recovery-phase control, not by viral injury or immune dysfunction alone.

Endothelium as an execution surface (exposure of failure)

Nunes et al. correctly identify the endothelium as a primary execution surface at which pathological consequences of post-viral stress become functionally visible. Senescent endothelial cells exhibit impaired shear sensing and vasodilatory responses (elevated endothelin-1 with reduced eNOS/NO signaling), increased permeability at the blood–brain and gut barriers, and pro-coagulant and adhesive phenotypes. In GLA v2.7, these features explain how flow-topology errors during exertion and early recovery expose skeletal muscle and brain to mismatched perfusion demands, thereby priming PEM generation without requiring global hypoxia or fixed cardiac limitation.

ER–mitochondrial calcium mis-timing as the upstream driver of persistence

GLA v2.7 adds a critical mechanistic layer upstream of endothelial senescence: persistent ER–mitochondrial (ER–MAM) calcium mis-timing during recovery. Under repeated recovery-phase stress and redox imbalance, calcium handling at ER–MAM junctions fails to terminate cleanly. Instead of tightly gated release followed by full reuptake, calcium remains intermittently elevated in endothelial microdomains. This produces several effects that directly stabilize the Nunes phenotype:

• Innate immune signaling fails to terminate. Calcium-dependent interferon, stress-kinase, and inflammasome-related pathways remain primed, creating temporal overlap of innate immune signaling without cytokine escalation.
• A chronic “not-resolved” endothelial state emerges. Persistent calcium microdomain activity sustains SASP-like transcriptional programs and redox signaling even in the absence of ongoing viral replication.
• Vasomotor and barrier regulation destabilize. ER–MAM calcium mis-timing disrupts eNOS coordination, favors endothelin-biased vasoconstriction, and impairs junctional integrity—central features of the endothelial phenotype described by Nunes et al.

In this framing, endothelial senescence is not merely a fate decision but the stabilized surface expression of unresolved calcium-mediated signaling.

Immune clearance failure as a maintenance loop

Nunes et al. emphasize impaired immune clearance of senescent endothelial cells (e.g., reduced NK-cell cytotoxicity, macrophage dysfunction, complement deficits, and HLA-E–mediated immune evasion). GLA v2.7 integrates this as a clearance-bandwidth limitation that locks persistence once senescence is established. Importantly, ER–MAM calcium mis-timing also degrades mitochondrial signaling and cytotoxic precision in immune cells, providing a mechanistic bridge between calcium dysregulation and the immune failure that sustains senescent endothelium.

What GLA v2.7 adds—and constrains

GLA v2.7 extends and constrains the Nunes hypothesis by:

1. distinguishing generation (execution-surface exposure) from persistence (duration encoding and clearance limitation) and expression (symptom modulation);
2. explaining why endothelial senescence alone does not determine PEM duration unless coupled to Resolution Duration Memory (RDM) and clearance bottlenecks; and
3. providing a mechanistic account for low-amplitude, chronic signaling—failed calcium-dependent termination at ER–MAM interfaces—rather than invoking ongoing infection or escalating inflammation.

In summary, Nunes et al. compellingly explain what persists at the vascular surface. GLA v2.7 explains why that persistence fails to shut off—through recovery-phase termination failure, ER–MAM calcium mis-timing, and clearance-bandwidth limits that render endothelial innate immune signaling self-sustaining across cycles of stress and recovery.

Mapping Nunes et al. mechanisms to GLA v2.7

Integration of the Paul et al. (2021) Hypothesis within GLA v2.7

Paul et al. (2021) propose that myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID can be understood as disorders of redox imbalance, producing chronic, low-grade physiological dysfunction without requiring ongoing infection or sustained cytokine elevation. Their synthesis integrates sulfur biology (hydrogen sulfide, H₂S), nitric oxide (NO), reactive oxygen and nitrogen species (ROS/RNS), mitochondrial respiratory control, and ischemia–reperfusion injury to explain prolonged symptoms, relapse dynamics, and incomplete recovery.

This work is particularly strong because it (i) explains persistence without invoking cytokine storms, (ii) unifies vascular, mitochondrial, and immune phenomena through redox control rather than ATP deficiency, and (iii) predicts phase-dependent intervention effects—why a treatment may transiently help yet later worsen post-exertional malaise (PEM). These features make Paul et al. a natural biochemical integrator within the GLA v2.7 architecture.

Redox imbalance as a driver of signal-termination failure

Within GLA v2.7, redox imbalance is positioned as a substrate-level driver of impaired signal termination rather than as a primary disease initiator. Paul et al. show that ROS/RNS excess and thiol redox disruption corrupt the normal “off-switch” behavior of signaling systems across vascular, immune, and metabolic domains. In GLA terms, this biochemical environment degrades termination precision, producing prolonged decay and temporal overlap of signaling activity rather than clean resolution.

This interpretation reframes redox pathology from “more activation” to failure of deactivation, providing a mechanistic basis for signal-resolution impairment and explaining why low-amplitude abnormalities can nevertheless have outsized effects on recovery.

Ischemia–reperfusion as recovery-phase injury encoding

Paul et al. emphasize ischemia–reperfusion–like mechanisms as central to symptom persistence. GLA v2.7 sharpens the temporal interpretation of this observation. Rather than locating injury primarily during exertion, GLA places oxidative amplification and injury encoding in the recovery phase, when perfusion and metabolic signaling should normalize.

In this framing, exertion exposes flow-distribution and shear mismatches, while recovery is where ROS amplification, mitochondrial stress, and tissue injury become biologically encoded. This ordering resolves the characteristic delay of PEM and aligns with empirical findings that muscle and metabolic abnormalities are most evident after, not during, exertion.

Nitric oxide biology as a timing and localization problem

Paul et al. connect NO metabolism to oxidative stress and endothelial dysfunction. GLA v2.7 adds a critical refinement: in many cases, NO is not absent but mistimed or mislocalized. Redox imbalance disrupts NO signaling reliability at the endothelial surface, increasing sensitivity to shear stress and impairing flow-topology regulation during recovery.

This distinction explains why NO-boosting or vasodilatory strategies can be inconsistent or paradoxical—sometimes improving symptoms transiently, sometimes worsening PEM—depending on the state of termination and recovery timing.

Reframing H₂S dysregulation as a phase-sensitive amplifier

Paul et al. effectively recontextualize earlier sulfur-based hypotheses, including Lemle (2009), by embedding H₂S within a broader redox signaling network. Within GLA v2.7, H₂S is interpreted as a context-dependent amplifier: capable of protective effects under intact termination, but destabilizing under impaired recovery, where it can influence K_ATP channels, ryanodine receptors, SERCA function, and mitochondrial signaling.

This reframing moves H₂S from a putative toxin or primary lesion to a state-dependent modulator of recovery-phase injury and signal persistence.

What GLA v2.7 adds beyond Paul et al.

While Paul et al. provide a powerful synthesis of how redox imbalance can maintain physiological dysfunction, their model does not fully specify where persistence is stored or why symptoms remain self-sustaining despite rest. GLA v2.7 completes the model by introducing (i) Resolution Duration Memory (RDM) as the biological encoding of unresolved recovery duration (with adipose tissue as a dominant reservoir) and (ii) clearance bandwidth as the determinant of symptom severity and persistence, particularly via liver–spleen processing of stress-encoded outputs such as RBC-derived extracellular vesicles.

In GLA terms, redox imbalance explains how dysfunction is amplified, while RDM and clearance limitation explain how dysfunction becomes self-sustaining.

Canonical synthesis

Paul et al. (2021) provide a redox-centered synthesis linking ME/CFS and Long COVID through ROS/RNS and sulfur/NO network misregulation. Within GLA v2.7, these findings are integrated as the biochemical substrate of signal-termination failure and recovery-phase ischemia–reperfusion amplification, while long-term chronicity and PEM duration are attributed to resolution-duration encoding and clearance-bandwidth constraints that extend beyond redox imbalance alone.

Mapping Paul et al. (2021) mechanisms to GLA v2.7

Integration of the Carnac Phosphatidylcholine–Noradrenergic Hypothesis within GLA v2.7

Carnac correctly identifies norepinephrine and broader catecholaminergic dysregulation as central to the symptomatology of ME/CFS, placing noradrenergic neuron dysfunction at the core of autonomic instability, vascular dysregulation, cognitive impairment, sleep disturbance, and post-exertional worsening (preprints202409.1467.v2). Her hypothesis provides a detailed and biologically grounded account of how altered insulin signaling, reduced norepinephrine transporter (NET) function, prolonged extracellular norepinephrine exposure, and β₂-adrenergic receptor down-regulation can generate self-reinforcing neuroendocrine and autonomic loops that shape symptom expression.

Within the GLA v2.7 framework, these observations are retained but repositioned. The Carnac model is not treated as a primary explanation of persistence or chronicity, but is instead integrated as a downstream execution-surface and symptom-expression model that emerges under conditions of unresolved recovery.

Constraint 1: Phosphatidylcholine deficiency is not initiating

In GLA v2.7, chronic Signal Resolution Layer (SRL) failure produces repeated recovery-phase stress that does not fully terminate. This persistent non-closure engages adaptive maintenance gating (Axis-2), which throttles lipid synthesis, redistribution, and membrane repair as a protective response. Over time, this produces secondary reductions in phosphatidylcholine (PC) availability, particularly at membranes with high turnover demands. PC deficiency therefore reflects maintenance austerity under unresolved recovery, not an initiating lesion.

Constraint 2: Membrane instability is mediated by SMPDL3B anchoring failure

GLA further constrains membrane fragility to SMPDL3B anchoring failure, rather than PC loss alone. SMPDL3B is a GPI-anchored regulator that stabilizes sphingomyelin–PC balance at execution surfaces. In deficient phenotypes, unresolved recovery erodes NAD⁺–SIRT1–c-Myc–dependent maintenance programs, impairing GPI-anchor renewal and reducing membrane-anchored SMPDL3B. In shedding phenotypes, immune overshoot activates PI-PLC–mediated cleavage of GPI anchors, actively releasing SMPDL3B from the membrane. In both cases, reduced membrane-anchored SMPDL3B amplifies PC-related fragility and signaling noise without creating new activation.

Constraint 3: Catecholamine and insulin abnormalities are expression-layer consequences

Under GLA rules, altered insulin sensitivity, NET dysregulation, and β₂-adrenergic receptor changes are expression-layer consequences, not persistence mechanisms. These abnormalities reflect signaling occurring on lipid-fragile, poorly stabilized membranes during unresolved recovery, rather than a self-sustaining neuroendocrine loop. They shape symptom visibility—orthostatic intolerance, cognitive dysfunction, sleep disturbance—but do not explain multi-day duration, stacking of post-exertional malaise, or self-maintenance of illness.

What the Carnac model does not specify—and what GLA adds

While Carnac’s framework compellingly explains how catecholaminergic dysregulation can generate and modulate symptoms, it does not specify a mechanism for termination failure, duration encoding, or clearance-limited chronicity—that is, why norepinephrine dysregulation fails to shut off across recovery cycles, why symptoms accumulate over time, or why illness persists despite prolonged rest. GLA v2.7 addresses this gap by introducing upstream signal-resolution failure, ER–mitochondrial calcium mis-timing, SMPDL3B-mediated membrane fragility, and downstream clearance bottlenecks, culminating in Resolution Duration Memory (RDM) encoded in adipose tissue.

Canonical synthesis

Within GLA v2.7, the Carnac phosphatidylcholine–noradrenergic hypothesis is integrated as a downstream membrane-instability and symptom-expression model, constrained by Axis-2 maintenance throttling and SMPDL3B anchoring failure. Catecholamine dysregulation is essential for explaining how symptoms are generated and modulated, but persistence arises only when recovery fails to complete and duration becomes biologically stored—processes that extend beyond catecholamine signaling alone.

Mapping Carnac (2025) mechanisms to GLA v2.7

SMPDL3B as a trunk-level membrane brake in ME/CFS persistence

A critical advance in ME/CFS biology is the identification of SMPDL3B as a membrane-anchored regulator whose loss is associated with disease severity and immune hypersensitivity. In a large translational study, Rostami-Afshari et al. demonstrated that individuals with ME/CFS show reduced membrane-bound SMPDL3B on monocytes, accompanied in many cases by increased soluble SMPDL3B, consistent with active GPI-anchor cleavage rather than reduced expression alone (J Transl Med, 2025).

SMPDL3B functions as a membrane-level signal brake, stabilizing sphingomyelin–phosphatidylcholine balance and dampening innate immune reactivity at execution surfaces. When membrane-anchored SMPDL3B is reduced, termination precision deteriorates: low-grade “not-resolved” signaling becomes easier to sustain, and recovery-phase activity is more likely to persist across stress cycles.

Within the GLA v2.7 framework, loss of membrane SMPDL3B is therefore interpreted not as a symptom generator, but as a permissive trunk-level change that increases the probability of multi-day post-exertional malaise (PEM) and persistence once recovery fails. This trunk is shared across ME/CFS presentations, even though symptom expression varies.

GLA distinguishes two mechanistic routes to low membrane SMPDL3B: (1) SMPDL3B shedding, driven by ER–MAM Ca²⁺ persistence and PI-PLC–mediated GPI-anchor cleavage during unresolved defensive states, and (2) SMPDL3B deficiency, arising from Axis-2 maintenance throttling and MLL (NAD⁺→SIRT1→c-Myc) erosion that impairs membrane renewal. These represent distinct control states with a shared surface outcome.

Importantly, symptom heterogeneity in ME/CFS is explained downstream of this trunk. In GLA terms, the M-subtypes (M1 muscle/metabolic, M2 vascular, M3 autonomic/low-volume) describe where execution stress and Ca²⁺ mis-timing are expressed, not which SMPDL3B phenotype is present. Thus, all ME/CFS patients share a persistence trunk compatible with PEM, while dominant symptoms depend on the most fragile execution surface.

This interpretation treats SMPDL3B as a convergence point for persistence permission, not as a single-cause explanation. Figure 8 illustrates how identical recovery-phase Ca²⁺ stress produces either active shedding or passive deficiency depending on control-state context.

Reference: Rostami-Afshari B. et al. SMPDL3B: a novel biomarker and therapeutic target in myalgic encephalomyelitis. Journal of Translational Medicine, 2025.

Figure 8 — SMPDL3B Phenotypes (Deficient vs Shedding)