Live·Open questions in longevity research
← Questions

Can aging human skin be shifted into a stable, youthful functional state, and what minimal set of changes in cells, the extracellular matrix, stem cell niches, the vasculature, and the nervous system is necessary and jointly sufficient to achieve and maintain this transition?

Does restoring skin nerves before reducing inflammation worsen protection, and can sensation, blood flow, and sweating coordinate without nerve growth?

The proposed chain begins with nerve signals influencing what skin senses, how blood moves through it, and when it sweats. One supplied source describes a route from nerve-related signaling to inflammation, but does not establish that adding nerves increases that response.

The whole reason

[S4] If nerve restoration amplified harmful inflammation before improving these functions, treating nerve number as a sufficient measure of recovery could misidentify deterioration as success. Conversely, if coordinated function returned without nerve growth, increased nerve density would not be necessary for that particular recovery. Sweating could also remain impaired because the glands themselves malfunction, a possibility reported in a specific muscle disease rather than established for aging skin. [S5]

The question in full

The question concerns whether aging human skin needs more nerves, better-controlled nerve signals, or both to regain protective responses. It asks whether increasing nerve density before correcting inflammatory gain makes protection worse, compared with correcting that amplification first and restoring nerves afterward. It also asks whether coordinated sensation, perfusion, and sweating can recover without neural expansion. The proposed comparison requires repeated sensory and temperature challenges, responses matching youthful reference levels, and coordination within time windows defined beforehand. The question assumes that nerve signaling can support protection while also driving inflammation, but the supplied evidence does not establish that this creates an order-dependent problem in aging human skin.

Competing hypotheses

These hypotheses propose different mechanisms. Comparing their predictions helps identify observations that could distinguish them.

  1. 01Regrowing skin nerves can erase protective signals when opposing impulses collideIn aged skin, nerve growth may reduce protective signaling when impulses traveling in opposite directions cancel each other. Immediately restoring transmission by selectively blocking the interfering traffic, without changing nerve density or inflammation, would distinguish this explanation.
  2. 02Correcting nerve signal timing can restore skin protection without adding nerve fibersIn innervated skin preparations, the hypothesis predicts that narrowing signal delays restores protective response timing, blood flow and sweating without adding fibers. Disrupting timing while keeping delivered activity unchanged would abolish recovery.
  3. 03Sweat glands need continuing nerve signals to retain their ability to respondIn aged human skin, sweat glands may remain unresponsive despite correctly timed nerve impulses. Recovery after repeated conditioning through acetylcholine signaling and drug washout, without more nerve fibers or less inflammation, would support a loss of maintained gland responsiveness.
Each entry represents a published hypothesis. Where no hypotheses are published yet, the entries show possible answers to the scientific question.

What results would tell us about the hypotheses

Choose a possible result to see which hypothesis it would support, what the alternatives predict, and what would need to be tested next.

If we observe
After neural expansion, simultaneous distal and proximal recordings will show increased terminal responses but fewer centrally arriving stimulus-locked spikes. Reversible direction-selective suppression of antidromic traffic will immediately restore protective signal transmission despite unchanged fiber density, inflammatory mediators and terminal sensitivity. Restoring the interfering traffic will abolish rescue. Failure to detect collision-timed missing spikes, or persistence of dysfunction after verified collision suppression, rejects this explanation in favor of downstream coordination or target-competence limitations. Hypothetical result
Would support the hypothesis
Regrowing skin nerves can erase protective signals when opposing impulses collide — In aged skin, nerve growth may reduce protective signaling when impulses traveling in opposite directions cancel each other. Immediately restoring transmission by selectively blocking the interfering traffic, without changing nerve density or inflammation, would distinguish this explanation.
Other hypotheses predict
  • Correcting nerve signal timing can restore skin protection without adding nerve fibers — At matched fiber density, total spike count, mean inflammatory activity and isolated effector capacity, experimentally compressing transmission-delay dispersion will restore protective latency and coordinated perfusion–sweating responses. Introducing timing jitter with the same delivered activity will abolish restoration. Proximal afferent spike transmission will remain intact, distinguishing this from impulse cancellation. Correctly timed direct stimulation will elicit normal gland output without days of conditioning, distinguishing it from target-competence loss.
  • Sweat glands need continuing nerve signals to retain their ability to respond — Sites that recover protective sensation and perfusion but retain poor sweating will also show reduced secretion after direct muscarinic stimulation, despite correctly timed sudomotor impulses. Repeated physiological cholinergic conditioning will restore subsequent challenge-evoked secretion after acute agonist effects wash out, without increased fiber density or further inflammatory reduction. Immediate rescue by timing correction, with normal initial direct-agonist responsiveness, rejects this mechanism.
What to check next
In aging human skin, does restoring nerve density before reducing inflammatory amplification produce different protective responses than reversing that order?

These are hypothetical results. Selecting one shows what would follow from it; it does not confirm a hypothesis or change its assessment.

Comparing hypotheses

Compare the proposed mechanisms, the predictions that distinguish the hypotheses, and the observations that would count against each one.

01

Regrowing skin nerves can erase protective signals when opposing impulses collide

Axonal impulse interference
Proposed mechanism

In aged skin, nerve growth may reduce protective signaling when impulses traveling in opposite directions cancel each other.

Full text

Regenerating sensory terminals can reduce protective information through collisions between stimulus-evoked orthodromic impulses and spontaneous antidromic impulses within the same axon. Inflammatory sensitization raises spontaneous initiation, while neural expansion adds initiation sites, increasing collision-dependent erasure of protective signals. The relevant substrate is ongoing bidirectional impulse traffic, not fiber abundance or a learned neural state. Correcting inflammatory gain before expansion reduces collisions, but selectively suppressing antidromic traffic should make gain correction dispensable. Improved protective input should also improve challenge-evoked coordination when sensory input is limiting; independently defective autonomic fibers remain a separate requirement.

What distinguishes its prediction

After neural expansion, simultaneous distal and proximal recordings will show increased terminal responses but fewer centrally arriving stimulus-locked spikes.

Full text

Reversible direction-selective suppression of antidromic traffic will immediately restore protective signal transmission despite unchanged fiber density, inflammatory mediators and terminal sensitivity. Restoring the interfering traffic will abolish rescue. Failure to detect collision-timed missing spikes, or persistence of dysfunction after verified collision suppression, rejects this explanation in favor of downstream coordination or target-competence limitations.

What would weaken the hypothesis

Correcting nerve signal timing can restore skin protection without adding nerve fibers predicts instead: At matched fiber density, total spike count, mean inflammatory activity and isolated effector capacity, experimentally compressing transmission-delay dispersion will restore protective latency and coordinated perfusion–sweating responses.

Full text

Introducing timing jitter with the same delivered activity will abolish restoration. Proximal afferent spike transmission will remain intact, distinguishing this from impulse cancellation. Correctly timed direct stimulation will elicit normal gland output without days of conditioning, distinguishing it from target-competence loss.

Sweat glands need continuing nerve signals to retain their ability to respond predicts instead: Sites that recover protective sensation and perfusion but retain poor sweating will also show reduced secretion after direct muscarinic stimulation, despite correctly timed sudomotor impulses. Repeated physiological cholinergic conditioning will restore subsequent challenge-evoked secretion after acute agonist effects wash out, without increased fiber density or further inflammatory reduction. Immediate rescue by timing correction, with normal initial direct-agonist responsiveness, rejects this mechanism.

02

Correcting nerve signal timing can restore skin protection without adding nerve fibers

Information and sensing
Proposed mechanism

In innervated skin preparations, the hypothesis predicts that narrowing signal delays restores protective response timing, blood flow and sweating without adding fibers.

Full text

The limitation is temporal reachability across otherwise functional sensory, autonomic, vascular and glandular response events. Inflammatory gain broadens response timing enough that protective and heat-loss responses cease to arrive within their required coordination windows. Additional fibers increase event counts without necessarily restoring timely transmission. Gain correction before neural expansion should permit coordinated recruitment, whereas sufficiently precise timing correction should rescue function at the original reduced density. The operative state is the distribution of transmission delays on fixed anatomical connections.

What distinguishes its prediction

At matched fiber density, total spike count, mean inflammatory activity and isolated effector capacity, experimentally compressing transmission-delay dispersion will restore protective latency and coordinated perfusion–sweating responses.

Full text

Introducing timing jitter with the same delivered activity will abolish restoration. Proximal afferent spike transmission will remain intact, distinguishing this from impulse cancellation. Correctly timed direct stimulation will elicit normal gland output without days of conditioning, distinguishing it from target-competence loss.

What would weaken the hypothesis

Regrowing skin nerves can erase protective signals when opposing impulses collide predicts instead: After neural expansion, simultaneous distal and proximal recordings will show increased terminal responses but fewer centrally arriving stimulus-locked spikes.

Full text

Reversible direction-selective suppression of antidromic traffic will immediately restore protective signal transmission despite unchanged fiber density, inflammatory mediators and terminal sensitivity. Restoring the interfering traffic will abolish rescue. Failure to detect collision-timed missing spikes, or persistence of dysfunction after verified collision suppression, rejects this explanation in favor of downstream coordination or target-competence limitations.

Sweat glands need continuing nerve signals to retain their ability to respond predicts instead: Sites that recover protective sensation and perfusion but retain poor sweating will also show reduced secretion after direct muscarinic stimulation, despite correctly timed sudomotor impulses. Repeated physiological cholinergic conditioning will restore subsequent challenge-evoked secretion after acute agonist effects wash out, without increased fiber density or further inflammatory reduction. Immediate rescue by timing correction, with normal initial direct-agonist responsiveness, rejects this mechanism.

03

Sweat glands need continuing nerve signals to retain their ability to respond

Activity dependent effector competence
Proposed mechanism

In aged human skin, sweat glands may remain unresponsive despite correctly timed nerve impulses.

Full text

The decisive omission is sustained transmitter-dependent maintenance of eccrine secretory competence. Aged or partially denervated glands can lose the machinery needed to respond even when new autonomic fibers subsequently deliver correctly timed impulses. Gain-first treatment helps only if it preserves the physiological cholinergic conditioning needed by the glands; indiscriminate neural suppression can therefore improve itch while making joint restoration fail. Neural expansion is dispensable where surviving fibers can maintain gland competence, but transient anti-inflammatory rescue alone cannot substitute for this continuing trophic input.

What distinguishes its prediction

Sites that recover protective sensation and perfusion but retain poor sweating will also show reduced secretion after direct muscarinic stimulation, despite correctly timed sudomotor impulses.

Full text

Repeated physiological cholinergic conditioning will restore subsequent challenge-evoked secretion after acute agonist effects wash out, without increased fiber density or further inflammatory reduction. Immediate rescue by timing correction, with normal initial direct-agonist responsiveness, rejects this mechanism.

What would weaken the hypothesis

Regrowing skin nerves can erase protective signals when opposing impulses collide predicts instead: After neural expansion, simultaneous distal and proximal recordings will show increased terminal responses but fewer centrally arriving stimulus-locked spikes.

Full text

Reversible direction-selective suppression of antidromic traffic will immediately restore protective signal transmission despite unchanged fiber density, inflammatory mediators and terminal sensitivity. Restoring the interfering traffic will abolish rescue. Failure to detect collision-timed missing spikes, or persistence of dysfunction after verified collision suppression, rejects this explanation in favor of downstream coordination or target-competence limitations.

Correcting nerve signal timing can restore skin protection without adding nerve fibers predicts instead: At matched fiber density, total spike count, mean inflammatory activity and isolated effector capacity, experimentally compressing transmission-delay dispersion will restore protective latency and coordinated perfusion–sweating responses. Introducing timing jitter with the same delivered activity will abolish restoration. Proximal afferent spike transmission will remain intact, distinguishing this from impulse cancellation. Correctly timed direct stimulation will elicit normal gland output without days of conditioning, distinguishing it from target-competence loss.

No test is published for this question yet

The hypotheses above state the observations that could distinguish them. A proposed experiment for this question has not yet been published.

What to check next: In aging human skin, does restoring nerve density before reducing inflammatory amplification produce different protective responses than reversing that order?

Every proposed test →

What the literature settles, and what it does not

The sources read against this question, the assumption it rests on, and the verdict that follows.

Does restoring skin nerves before reducing inflammation worsen protection, and can sensation, blood flow, and sweating coordinate without nerve growth?

What this question is asking

The question concerns whether aging human skin needs more nerves, better-controlled nerve signals, or both to regain protective responses. It asks whether increasing nerve density before correcting inflammatory gain makes protection worse, compared with correcting that amplification first and restoring nerves afterward. It also asks whether coordinated sensation, perfusion, and sweating can recover without neural expansion. The proposed comparison requires repeated sensory and temperature challenges, responses matching youthful reference levels, and coordination within time windows defined beforehand. The question assumes that nerve signaling can support protection while also driving inflammation, but the supplied evidence does not establish that this creates an order-dependent problem in aging human skin.

What the terms mean
Nerve density and neural expansion
Nerve density is the amount or number of nerve fibers within a defined area or volume of tissue. Neural expansion means increased nerve growth or supply; an increase in density does not by itself demonstrate better signaling or protection.
Inflammatory gain
The proposed degree of amplification between a triggering signal and the resulting inflammatory response. The supplied material does not define a measurement for it or establish what would count as correcting it.
Inflammation
A tissue response involving immune activity. Here it is the potentially harmful response that nerve-related signaling might amplify; its magnitude and functional effects are not established by the supplied intervention evidence.
Protective function
The skin's capacity to respond in ways that limit harm. The question connects this to feeling, blood supply, and sweating, but does not provide a direct protection endpoint.
Sensation and sensory nerves
Sensation is the detection of stimuli, and sensory nerves carry signals contributing to that detection. S1 also concerns their influence on skin blood-vessel responses.
Perfusion
Blood flow through tissue. In this question, its recovery must occur in coordination with sensation and sweating.
Autonomic nerves and sudomotor function
Autonomic nerves regulate automatic bodily responses; sudomotor function refers specifically to sweating. Sensory recovery and recovery of these automatic responses are distinct outcomes.
Youthful thresholds, acute coordination windows, and phase-matched challenges
These are proposed assessment conventions: reference response levels from young skin, predefined short periods within which responses must align, and challenges compared at corresponding stages. No values or operational definitions are supplied.
Epidermal nerve fibers
Nerve fibers in the skin's outer layer. Their abbreviation in S2 is ENF, and their reduced density was observed after previous surgical skin lifting.
Mast cells
Immune cells found in tissues, including skin. S2 reports qualitative changes in them but the supplied quote does not establish their contribution to functional recovery.
Peripheral nerve injury and the autonomous area
A peripheral nerve is a nerve outside the brain and spinal cord. Its autonomous area is a region supplied by that nerve without overlapping supply from neighboring nerves; S3 reports recovery within such an area of the palm.
Collateral reinnervation
Renewed nerve supply through branches growing from neighboring surviving nerves. It is one route of nerve recovery, so independence from it does not establish independence from every form of nerve growth.
Transient receptor potential vanilloid 1
A cellular channel, abbreviated TRPV1, involved in sensory signaling. S4 describes its activation allowing calcium ions to enter cells and initiating a sequence that leads to inflammation.
Calcium ions, neuropeptides, and neurogenic inflammation
Calcium ions are electrically charged calcium particles that can carry signals inside cells; neuropeptides are small protein-like signaling molecules released by nerve cells. Neurogenic inflammation is inflammation triggered by nerve activity, the outcome of the sequence described in S4.
Myotonic dystrophy
The muscle disease abbreviated MyD in S5. Its reported sweating deficit provides disease-specific evidence about gland dysfunction, not a finding about ordinary skin aging.
Eccrine glands and postganglionic autonomic nerves
Eccrine glands produce sweat. Postganglionic autonomic nerves carry automatic-control signals from nerve relay stations to target tissues; S5 distinguishes malfunction of the glands from malfunction of these supplying nerves.
C fibers and metabolic processes
C fibers are a class of small nerve fibers that includes fibers supplying sweat glands. Metabolic processes are the body's chemical activities; S7 identifies damage associated with these processes as a vulnerability of those fibers.
Adrenergic fibers and functional coupling
Adrenergic fibers are nerves that signal using chemical messengers such as noradrenaline. Functional coupling means linked activity; S8 suggests it from nearby fiber locations, which does not by itself demonstrate coordinated functional responses.
What the question takes for granted
Premise only partly supported
Neural signaling contributes to both protection and inflammatory dysfunction, with different sensory and autonomic recovery trajectories that may make intervention order decisive.

Nerves carry signals involved in feeling and in automatic responses such as blood-flow changes and sweating. The question assumes that these signals can both help protect skin and amplify inflammation, and that feeling and automatic responses recover differently. If those assumptions held in aging skin, they would provide a reason to distinguish adding nerves from controlling their signals and to consider which change comes first.

S1 reports an association in rats between declining sensory-nerve control of skin blood-vessel responses and declining wound repair. S4 describes a signaling pathway that initiates nerve-triggered inflammation. These support narrower components of the proposed tension, not an established conflict caused by restoring nerves in aging human skin. S3 addresses final sensory and sweating recovery after nerve injury, but its supplied quote does not establish different recovery trajectories. None of the supplied sources establishes that inflammatory gain must be corrected before nerve restoration. The RL-1–RL-3 evidence labels in the gap description are not identifiable supplied source ids and cannot provide additional support.S1S3S4

The same question asked without the part nothing read establishes:

  • In aging human skin, does restoring nerve density before reducing inflammatory amplification produce different protective responses than reversing that order?
  • Can aging human skin recover coordinated sensation, blood flow, and sweating without increased nerve density?
What turns on the answer
  • Inflammation control must come first If added nerves increased signals that amplify inflammation, restoring them first could worsen protective responses. If controlling that amplification first prevented the worsening, intervention order would affect whether nerve restoration helped.
  • Nerve growth is necessary, but order is not If coordinated responses recovered only when nerve density increased, nerve growth would be necessary under the assessed conditions. If both intervention orders produced equivalent recovery, the claimed requirement to correct inflammation first would not hold under those conditions.
  • Coordination recovers without nerve growth If sensation, blood flow, and sweating met the specified response and timing requirements without increased nerve density, neural expansion would be dispensable for that recovery. This would establish that additional nerves were unnecessary under those conditions, while leaving the role of existing nerves intact.
  • Neither order restores coordinated protection If both orders failed to restore the required responses, combining nerve restoration with inflammation control would not be sufficient under the assessed conditions. That failure alone would not determine whether nerve growth was necessary or whether another limitation prevented recovery.
Why it matters

The proposed chain begins with nerve signals influencing what skin senses, how blood moves through it, and when it sweats. One supplied source describes a route from nerve-related signaling to inflammation, but does not establish that adding nerves increases that response. [S4] If nerve restoration amplified harmful inflammation before improving these functions, treating nerve number as a sufficient measure of recovery could misidentify deterioration as success. Conversely, if coordinated function returned without nerve growth, increased nerve density would not be necessary for that particular recovery. Sweating could also remain impaired because the glands themselves malfunction, a possibility reported in a specific muscle disease rather than established for aging skin. [S5]

Still open

None of the supplied sources tests the intervention-order question or whether all three functions recover together without nerve growth in aging human skin. The nearest functional evidence, S3, concerns final sensory and sweating recovery after palm nerve injury and independence from collateral reinnervation alone. S1 supplies an aging-related association in rats, S4 supplies an inflammation mechanism, and S5 identifies gland dysfunction in a different disease setting. The inference from these sources is that nerve abundance cannot be assumed to establish coordinated protection; that is a synthesis, not a finding directly reported by any one source. The question remains open within this read set, which does not establish that it is unanswered throughout the literature.S3S1S4S5

What the literature establishes
  • The rat abstract reports that an age-related decline in sensory-nerve modulation of skin blood-vessel responses correlates with declining wound-repair effectiveness. This is an association, not evidence that restoring nerve density reverses either decline.S1
  • In an observational study of facelift patients, previous surgical lifting of the skin was associated with fewer epidermal nerve fibers and qualitative changes in deeper skin nerves, small blood vessels, and mast cells.S2
  • Following peripheral nerve injury and repair in human palms, final sensory and sweating recovery within the injured nerve's autonomous area did not depend on possible collateral reinnervation. This finding concerns one route of renewed nerve supply, rather than the necessity of all nerve growth.S3
  • The review abstract reports that activation of transient receptor potential vanilloid 1 channels allows calcium ions to enter cells, leading to neuropeptide release and initiation of neurogenic inflammation. It does not report what happens when skin nerve density is restored.S4
  • The myotonic dystrophy abstract attributes local sweating deficiency as the disease progresses to eccrine-gland dysfunction rather than dysfunction of postganglionic autonomic nerves.S5
  • S7 describes C fibers supplying sweat glands and identifies them as vulnerable to damage from metabolic processes. It does not establish that increasing their number restores sweating.S7
  • The descriptive human skin study reports fibers running close to adrenergic fibers and interprets that proximity as suggesting functional coupling. The supplied quote does not demonstrate coordinated sensation, blood flow, and sweating.S8
What it does not settle
  • Whether restoring nerve density worsens protective function in aging human skin, and whether prior correction of inflammatory amplification prevents such worsening.
  • Whether reversing the order of nerve restoration and inflammation control changes the magnitude, timing, or durability of functional recovery.
  • Whether increased nerve density is necessary for coordinated sensation, blood flow, and sweating. Independence from collateral reinnervation after palm nerve injury does not establish independence from all nerve growth in aging skin.S3
  • The supplied material gives no numerical youthful reference thresholds, defined acute coordination windows, repeated-challenge results, or duration over which a recovered state remains stable.
  • The material does not specify a direct measure of protective function or establish how meeting the proposed sensory, blood-flow, and sweating criteria translates into protection from harm.
  • Whether impaired sweating in aging skin is limited by nerve function, gland function, or both; the disease-specific gland finding does not settle this population.S5
Where the sources disagree
  • S5 conflicts with a nerve-only explanation of impaired sweating: its abstract attributes the deficit in myotonic dystrophy to sweat-gland dysfunction rather than the nerves supplying those glands. This preserves an alternative source of functional failure, but does not directly contradict an intervention-order claim in aging skin.S5
Sources read · 7

3 literature searches, 6 full texts, 4 abstract-only; 10 source(s) read in full against this question. A bounded search is not evidence of absence.

S1BackgroundAbstract only

Effects of aging on neurogenic vasodilator responses evoked by transcutaneous electrical nerve stimulation: relevance to wound healing. · The journals of gerontology. Series A, Biological sciences and medical sciences · 2000

“We have previously shown an age-related decline in the modulation of skin vascular reactivity by sensory nerves that correlates with a decline in wound repair efficacy.”

Does not settle: This rat abstract does not test restoration of nerve density, inflammatory gain correction, protective function worsening, reversed intervention sequences, sweating, coordinated sensation, or whether neural expansion is dispensable.

S2Partly answers it

Comparison of Neurovascular Characteristics of Facial Skin in Patients After Primary and Revision Rhytidectomies. · JAMA facial plastic surgery · 2017

“Prior skin elevation was associated with decreased ENF density and qualitative changes in dermal nerves, capillaries and mast cells in a clinical sample of rhytidectomy patients.”

Does not settle: This observational study does not test restoration of nerve density, inflammatory-gain correction, protective function, intervention order, sweating, coordinated perfusion and sensation, or whether neural expansion is dispensable.

S3Partly answers it

Contribution of collateral sprouting to the sensory and sudomotor recovery in the human palm after peripheral nerve injury. · British journal of plastic surgery · 1998

“End-stage sudomotor and sensory recovery within the autonomous area of the nerve did not depend on possible collateral reinnervation.”

Does not settle: This study assesses sensory and sudomotor recovery after peripheral nerve injury and repair in human palms. It does not test inflammation correction, whether restoring nerve density worsens protective function, perfusion, intervention order, reversed intervention sequences, or coordinated sensation, perfusion, and sweating.

S4BackgroundAbstract only

TRPV1 channels in skin homeostasis and disease: From sensory transduction to therapeutic targeting. · International immunopharmacology · 2026

“Upon activation, TRPV1 mediates Ca2+ influx, leading to neuropeptide release and the initiation of neurogenic inflammation.”

Does not settle: This abstract does not test restoration of nerve density, correction of inflammatory gain before neural expansion, reversed intervention sequences, or coordinated sensation, perfusion, and sweating outcomes.

S5Contradicts itAbstract only

[Sweating deficiency in myotonic dystrophy]. · Rinsho shinkeigaku = Clinical neurology · 1989

“These results suggests that local sweating deficiency develops in MyD as the disease progresses and that this deficiency is caused by dysfunction of eccrine glands, and not of postganglionic autonomic nerves.”

Does not settle: This abstract does not test restoration of nerve density, inflammatory gain correction, intervention order, neural expansion, coordinated sensation or perfusion, or sweating outcomes after an intervention.

S7Background

The Importance of Evaluating Sudomotor Function in the Diagnosis of Cardiac Autonomic Neuropathy. · Cureus · 2024

“The C fibers innervate the sweat glands and are typically thin, long, and poorly myelinated, rendering them highly vulnerable to damage from metabolic processes.”

Does not settle: This source does not test restoration of nerve density, inflammatory correction, intervention order, reversed sequences, sensation or perfusion outcomes, or whether neural expansion is dispensable.

S8Background

The autonomic innervation of hairy skin in humans: an in vivo confocal study. · Scientific reports · 2019

“They were usually running close to adrenergic fibers (i.e. stained by DbH and NPY), suggesting a strict functional coupling”

Does not settle: This descriptive biopsy study does not test restoring nerve density, inflammatory correction, intervention order, protective function, sensation, perfusion, sweating outcomes, or whether neural expansion is dispensable.

← Every open question