TRP - Transient receptor potential
Die Forschung der letzten 20 Jahre konnte über den Erklärungsansatz der neurogenen Entzündung hinaus etwas tiefer in die Thematik eindringen.
Eine Studie aus 2021 befasst sich mit genau dem in den letzten 20 Jahren gesammelten Wissen und arbeitet einige für MCS wichtige Befunde heraus.
Molot et al., 2021 J. Molot, M. Sears, L.M. Marshall, R.I. Bray
Neurological susceptibility to environmental exposures: pathophysiological mechanisms in neurodegeneration and multiple chemical sensitivity
Rev. Environ. Health (2021)
Den für jeden frei zugänglichen Download der Schrift erhält man über den folgenden Link:
https://www.researchgate.net/publicatio ... 7/download
Einige Auszüge in der Reihenfolge des Vorkommens:
„Most studies showing increased risks of developing chronic disease with outdoor air pollution consider the effects of long-term exposure.“
“Transient receptor potential (TRP) … This article is focused on two particular TRP receptors: subfamily vanilloid 1 (TRPV1) and subfamily ankyrin 1 (TRPA1).”
“Both channels function as chemosensory receptors.
The TRPV1 channel senses environmental pollutants and is activated by various common volatile compounds, such as m-xylene, toluene, styrene, benzene, ethylbenzene, acetone, diethyl ether, hexane, heptane and cyclohexane and formaldehyde [124-126], plus particulate matter pollution [127, 128].
The TRPA1 channel is robustly activated by a multitude of environmental chemical substances, including iso-cyanates, heavy metals, oxidizing agents, styrene, naphthalene, formaldehyde, tobacco smoke and multiple other VOCs [127, 129, 130]. This receptor is the most broadly-tuned chemosensory channel known. To date, more than 130 different chemicals have been identified as activators of TRPA1 receptors [131].”
131. Talavera K, Startek JB, Alvarez-Collazo J, Boonen B, Alpizar YA, Sanchez A, et al. Mammalian transient receptor potential TRPA1 channels: from structure to disease. Physiol Rev 2020;100: 725-803.
“TRPV1 and TRPA1 function together [134, 149], and their co-expression result in unique activation profiles that can be distinct from those of cells expressing only TRPA1 or TRPV1 [150]. Jointly, they modulate sensitivity, and they can sensitize each other [151, 152].
…
Sensitization involves receptor hyperexcitability and the perception of an input as noxious, even if it is from a normal, or even subthreshold, generally innocuous stimulus [162].”
162. Schumacher MA. TRP channels in pain and inflammation: therapeutic opportunities. Pain Pract Off J World Inst Pain 2010; 10:185-200.
“… This may be related to the fact that TRPV1 and TRPA1 can form complex units (TRPA1V1) in sensory neurons, called heterotetramers, which have distinct properties that are different from the individual channels [149]. When cells co-expressing these channels are challenged with chemicals, the TRPAIV1 heterotetramer is more commonly activated than either TRPA1 or TRPV1 alone [150]. In other words, the more oxidative stress and systemic inflammation, the more there is upregulation of these receptors. When they are both upregulated by shared triggers, they are co-expressed in close proximity [163], and thus they are more likely to form heterotetramers. This results in a lower threshold for a cellular response to chemical stimuli and enhances the strength and duration of the reactions [149].”
149. Lee L-Y, Hsu C-C, Lin Y-J, Lin R-L, Khosravi M. Interaction between TRPA1 and TRPV1: synergy on pulmonary sensory nerves. Pulm Pharmacol Therapeut 2015; 35:87-93.
“… Being deficient in nutritional support [165], or being overwhelmed by xenobiotic exposures can contribute to inadequate detoxification. Furthermore, genetic polymorphisms and epigenetic changes can reduce the capacity to metabolize xenobiotics and may thereby enhance their toxic effects [166]. Some people have more effective detoxification systems than others [167-169], which can help to explain the inter-individual variations in disease susceptibility.
…
The regulation of TRPV1 and TRPA1 activity is complex [215], and over-activation of these channels under pathological conditions can lead to elevated levels of intracellular Ca++ causing subsequent mitochondrial damage and apoptosis [216].
Deregulated TRPV1 activation promotes the loss of hippocampal neurons and an impairment of cognitive functions and has been directly implicated in cell death [217]. To reduce this excitability and maintain cell homeostasis, tight control of intracellular Ca++ levels in neurons is crucial to prevent neurodegeneration [218]. Most important in this regard are the Ca++ pumps, which export Ca++ ions out of the cell within milliseconds to restore physiological homeostasis promptly [219, 220]. Disruption of this precise regulation of intracellular Ca++ is considered to be a final common pathway leading to neuron dysfunction and cell death [221], and may also possibly play a role in nociception [222].
…
… Vitamin D modulates the function of TRPV1; for example, it antagonizes the stimulatory effects of TRPV1 agonists like capsaicin because it binds to TRPV1 within the same vanilloid binding pocket and reduces trigeminal signaling mediated by TRPV1 [228]. This suggests that when vitamin D levels are low this protection could be reduced. Another example of modulation is the effect of 250HD on protein kinase C (PKC), which sensitizes but does not activate TRPV1 [229]. Enhanced activity of PKC is associated with neurodegeneration [230], but 250HD reduces the PKC effect on TRPV1 sensitization [231].”
Bis hierhin einige wichtige Kernaussagen:
• Die Rezeptoren schaukeln sich hoch und befähigen sich gegeseitig auf geringste Konzentrationen der Auslöser zu reagieren. Die einzige Option, wie es weitergehen kann: Es wird immer heftiger. Die Totale Vermeidung bleibt als einziger Ausweg.
• Die Veranlagung spielt zwar eine Rolle, aber wohl nur eine untergeordnete. MCS erwirbt man – und man sollte mit dem erworbenen Schatz etwas anfangen, sagt EkelErtl. Siehe hier im Forum unter: „Neurogeneration und MCS“
viewtopic.php?t=5487 und gleich hier folgend.
• Wenn man die Überstimulation irgendwie aushalten will, kann das nur in den Untergang führen.
• Ein Vitamin-D-Mangel könnte bei „UNS“ den Anfang zu MCS gemacht haben. Vitamin D wird zur wichtigen Nahrungsergänzung, entweder um MCS zu vermeiden oder um MCS wenigstens irgendwie noch auszuhalten.
Weitere Auszüge:
“Potential consequences: multiple chemical sensitivity (MCS)
There is a significant body of evidence that many individuals are observing sensitivity to common chemicals. A 2015 national survey in the U.S.A. measured the prevalence of self-reported sensitivity to chemicals and medically diagnosed multiple chemical sensitivity (MCS) at 25.9 and 12.8% respectively [253].
MCS is an acquired condition in which the person experiences a range of recurrent symptoms attributed to exposures to low levels of chemicals that most people regard as unproblematic, and which the person used to tolerate previously as well [254].
… The MCS consensus definition was validated in 2000 [265], and includes the following [264]:
(1) The symptoms are reproducible with repeated chemical exposure.
(2) The condition is chronic.
(3) Low levels of exposure [lower than previously or commonly tolerated] result in manifestation of the symptoms.
(4) The symptoms improve or resolve when the incitants are removed.
(5) Responses occur to multiple chemically unrelated substances.
(6) Symptoms involve multiple organ systems.”
264. Multiple chemical sensitivity: a 1999 consensus. Arch Environ Health. 1999; 54:147-9.
“… Similar to neurodegenerative disorders, genetic polymorphisms predisposing to less efficient metabolism and excretion of commonly encountered environmental chemicals are more common in people who meet the criteria for MCS [267-272]. These findings have not been completely consistent [273, 274] however, a regression analysis published in 2019 reinforces the concept that a genetic risk related to phase I and II liver enzymes involved in xenobiotic detoxification can play a role in the pathophysiological route towards sensitization to olfactory compounds in MCS
[275]. Nevertheless, even in the absence of an abnormality among detoxification polymorphisms, oxidative stress and systemic inflammation are universally observed in MCS patients [276, 277]. There is also evidence suggesting that the BBB may be dysfunctional in MCS [278], which would enable greater chemical exposures in the CNS.”
“Comparison of neurodegeneration and MCS
The major risks to the CNS from chronic air pollution exposure are the development of neurodegenerative disease and/or MCS (Table 2). There are both similar and distinctive associated exposures, and genetic, pathophysiological and clinical features of neurodegenerative disorders and MCS (Table 2). Shared features include associated risks for adverse effects from airborne chemical pollutants according to one's genotype for detoxification and dysfunctional BBB; adverse effects on a cellular level, including oxidative stress, systemic inflammation and changes in polymodal TRPA1 and TRPV1 receptor function; and chronic pain and central sensitization. Neurodegenerative conditions involve olfactory nerve dysfunction, and MCS most likely involves the trigeminal nerve. The conditions diverge in how the TRPV1 and TRPA1 channels respond. Intriguingly, while people with neurodegeneration or MCS are more likely to experience …
Unlike neurodegenerative disorders, MCS patients do not demonstrate loss of olfactory nerve function or CNS mass, but do show olfactory processing dysfunction. The reason for this divergence of the pathophysiologic pathways to dysfunction and damage is not clear. Despite the overlapping exposures and mechanisms, there is no robust published evidence for comorbidity of neurodegeneration with MCS.”
Zwei sehr wichtige Annahmen zu MCS:
• Neurodegeneration und MCS funktionieren unterschiedlich. Es gibt keinerlei verlässliche Evidenz für eine Komorbidität, was heißt, dass eher das Gegenteil der Fall ist. „UNSERE“ Sinne funktionieren einfach nur zu gut – zu gut für diese Welt.
• MCS geht einher mit einer Schärfung des Geruchsinns. Die Neurodegeneration hingegen führt in die Abstumpfung und Schrumpfung.
Und aus vorigem Auszug vermerken wir den Hinweis auf die weitere Recherche: „MCS most likely involves the trigeminal nerve”
Für mich deutet sich eine weitere Erklärung an. In meinem Fall gab es die Abfolge
• Neurogenes Asthma bronchiale
• MCS
• CFS
Die ständige Überstimulation schädigt den Energiestoffwechsel. Man fällt ein zweites Mal in den Brunnen.
Für mich heißt das, dass ich nun aus zwei Brunnen zugleich herausklettern muss. Es braucht bei MCS-CFS diese spezielle Verständnis, dass CFS nur eine Nachfolge und nicht die Hauptfolge und die Mitochondriopathie auch nicht die Hauptursache ist. Ohne Verständnis von MCS kann „UNS“ weder ein Umweltarzt noch ein Spezialist für Mitochondrientherapie heraushelfen. Wir müssen zugleich auch aus dem ersten Brunnen heraus, in den wir vor CFS gefallen waren.
Und für alle anderen, die es bis an diese Stelle im Forum geschafft haben: Klettert auch aus dem ersten Brunnen heraus, wenn Ihr nicht ständig wieder in den zweiten Brunnen hineinfallen wollt – ab aufs Gravel-Bike und weg aus der innerörtlichen Seuche.
Noch der Schluss der Schrift:
“Conclusion
There are interacting and overlapping pathophysiological features of responses to environmental exposures that are associated with neurodegeneration and MCS. These include genotypes for detoxification, oxidative stress, systemic inflammation, disruption of the BBB, chronic pain, central sensitization, decreased cognition and upregulation of TRPV1 and TRPA1 receptors.
TRPA1 is the most promiscuous sensor of chemicals known. While much less literature examines sensitization of TRPA1 than TRPV1 receptors in MCS, it is clear that these receptors are frequently co-expressed and can sensitize and provoke responses in each other when stimulated.
They can combine to form a complex unit (which is the structure most commonly activated when challenged with chemicals in vitro) and they can interact synergistically.
TRPA1 and TRPV1 sensitization explains the myriad of chemicals to which MCS patients attribute reactions and observe sensitivities. Co-expression of TRPA1 and TRPV1 and formation of complex units may contribute to the severity of MCS. Further research on MCS should investigate TRPA1 sensitization, singularly and in conjunction with TRPV1. This may assist in finding a clinical marker for the diagnosis of MCS. Identifying TRPV1 and TRPA1 polymorphisms in neurodegenerative disorders and MCS may help to understand how air pollution influences the divergent development of these conditions and provide targets for management and treatment beyond placing a high priority on air pollution prevention and abatement.“