Tag: parasympathetic function

Plasma Neurofilament Light Chain: A Potential Biomarker for Neurological Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disorder characterized by heterogeneous symptoms, which lack specific biomarkers for its diagnosis. This study aimed to investigate plasma neurofilament light chain (NfL) levels as a potential biomarker for ME/CFS and explore associations with cognitive, autonomic, and neuropathic symptoms.

Here, 67 ME/CFS patients and 43 healthy controls (HCs) underwent comprehensive assessments, including neuropsychological evaluation, autonomic nervous system (ANS) testing, and plasma NfL level analysis. ME/CFS patients exhibited significantly higher plasma NfL levels compared to HC (F = 4.30, p < 0.05). Correlations were observed between NfL levels and cognitive impairment, particularly in visuospatial perception (r = -0.42; p ≤ 0.001), verbal memory (r = -0.35, p ≤ 0.005), and visual memory (r = -0.26; p < 0.05) in ME/CFS. Additionally, higher NfL levels were associated with worsened autonomic dysfunction in these patients, specifically in parasympathetic function (F = 9.48, p ≤ 0.003).

In ME/CFS patients, NfL levels explained up to 17.2% of the results in cognitive tests. Unlike ME/CFS, in HC, NfL levels did not predict cognitive performance. Elevated plasma NfL levels in ME/CFS patients reflect neuroaxonal damage, contributing to cognitive dysfunction and autonomic impairment.

These findings support the potential role of NfL as a biomarker for neurological dysfunction in ME/CFS. Further research is warranted to elucidate underlying mechanisms and clinical implications.

Source: Azcue N, Tijero-Merino B, Acera M, Pérez-Garay R, Fernández-Valle T, Ayo-Mentxakatorre N, Ruiz-López M, Lafuente JV, Gómez Esteban JC, Del Pino R. Plasma Neurofilament Light Chain: A Potential Biomarker for Neurological Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Biomedicines. 2024 Jul 11;12(7):1539. doi: 10.3390/biomedicines12071539. PMID: 39062112; PMCID: PMC11274366. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11274366/ (Full text)

A Case Report of Chronic Epipharyngitis With Chronic Fatigue Treated With Epipharyngeal Abrasive Therapy (EAT)

Abstract:

A case of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) with chronic epipharyngitis was treated with epipharyngeal abrasive therapy (EAT). The symptoms of ME/CFS improved along with the improvement of chronic epipharyngitis. The patient was followed up with endocrine and autonomic function tests.

Endocrine function tests included salivary cortisol and salivary α-amylase activity. Salivary α-amylase activity was stimulated by EAT. EAT improved the diurnal variability of salivary cortisol secretion. Autonomic function tests included heart rate variability analysis by orthostatic stress test. EAT normalized parasympathetic and sympathetic reflexes over time and regulated autonomic balance.

Based on the improvement of symptoms and test results, EAT was considered effective for ME/CFS. A literature review was conducted on the mechanism of the therapeutic effect of EAT on ME/CFS.

Source: Hirobumi I. A Case Report of Chronic Epipharyngitis With Chronic Fatigue Treated With Epipharyngeal Abrasive Therapy (EAT). Cureus. 2024 Feb 23;16(2):e54742. doi: 10.7759/cureus.54742. PMID: 38405656; PMCID: PMC10884883. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10884883/ (Full text)

Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and post-COVID condition can present similarities such as fatigue, brain fog, autonomic and neuropathic symptoms.

Methods: The study included 87 patients with post-COVID condition, 50 patients with ME/CFS, and 50 HC. The hemodynamic autonomic function was evaluated using the deep breathing technique, Valsalva maneuver, and Tilt test. The presence of autonomic and sensory small fiber neuropathy (SFN) was assessed with the Sudoscan and with heat and cold evoked potentials, respectively. Finally, a complete neuropsychological evaluation was performed. The objective of this study was to analyze and compare the autonomic and neuropathic symptoms in post-COVID condition with ME/CFS, and healthy controls (HC), as well as, analyze the relationship of these symptoms with cognition and fatigue.

Results: Statistically significant differences were found between groups in heart rate, with ME/CFS group presenting the highest (H = 18.3; p ≤ .001). The Postural Orthostatic Tachycardia Syndrome (POTS), and pathological values in palms on the Sudoscan were found in 31% and 34% of ME/CFS, and 13.8% and 19.5% of post-COVID patients, respectively. Concerning evoked potentials, statistically significant differences were found in response latency to heat stimuli between groups (H = 23.6; p ≤ .01). Latency was highest in ME/CFS, and lowest in HC. Regarding cognition, lower parasympathetic activation was associated with worse cognitive performance.

Conclusions: Both syndromes were characterized by inappropriate tachycardia at rest, with a high percentage of patients with POTS. The prolonged latencies for heat stimuli suggested damage to unmyelinated fibers. The higher proportion of patients with pathological results for upper extremities on the Sudoscan suggested a non-length-dependent SFN.

Source: Naiara Azcue, Rocio Del Pino, Marian Acera et al. Dysautonomia and small fiber neuropathy in post-COVID condition and Chronic Fatigue Syndrome, 06 October 2023, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-3388628/v1] https://www.researchsquare.com/article/rs-3388628/v1 (Full text)

Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome – a case-control study

Abstract:

Purpose: Eighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls.

Methods: Thirteen LCP and 16 healthy controls, all female subjects, were studied without medications. Continuous blood pressure and ECG were recorded during orthostatic stress test, respiratory sinus arrhythmia, and Valsalva maneuver. Time domain and power spectral analysis of heart rate [HR] and systolic blood pressure [SBP] variability were computed characterizing cardiac autonomic control and sympathetic peripheral vasoconstriction.

Results: LCP had higher deltaHR (+ 40 ± 6 vs. + 21 ± 3 bpm, p = 0.004) and deltaSBP (+ 8 ± 4 vs. -1 ± 2 mmHg, p = 0.04) upon standing; 47% had impaired Valsalva maneuver ratio compared with 6.2% in controls (p = 0.01). Spectral analysis revealed that LCP had lower RMSSD (32.1 ± 4.6 vs. 48.9 ± 6.8 ms, p = 0.04) and HFRRI, both in absolute (349 ± 105 vs. 851 ± 253ms2, p = 0.03) and normalized units (32 ± 4 vs. 46 ± 4 n.u., p = 0.02). LFSBP was similar between groups.

Conclusions: LCP have reduced cardiovagal modulation, but normal sympathetic cardiac and vasoconstrictive functions. Impaired parasympathetic function may contribute to the pathogenesis of Long-COVID POTS syndrome.

Source: Rigo S, Urechie V, Diedrich A, Okamoto LE, Biaggioni I, Shibao CA. Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome – a case-control study. Bioelectron Med. 2023 Sep 6;9(1):19. doi: 10.1186/s42234-023-00121-6. PMID: 37670400; PMCID: PMC10481607. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10481607/ (Full text)