Sex Differences in Hemodynamic Response to Exercise in Patients With Myalgic Encephalomyelitis: Insights From Invasive Cardiopulmonary Exercise Testing

Abstract:

Abstract available online: https://www.atsjournals.org/doi/10.1164/ajrccm-conference.2023.207.1_MeetingAbstracts.A2995

Source: K. Wichmann Madsen, J. Squires, M.C. Stovall, S. Al-Zayer, C.-J. Chang, W. Xiao, R. Pari, P. Joseph, D.M. Systrom. Sex Differences in Hemodynamic Response to Exercise in Patients With Myalgic Encephalomyelitis: Insights From Invasive Cardiopulmonary Exercise Testing. American Journal of Respiratory and Critical Care Medicine 2023;207:A2995 https://www.atsjournals.org/doi/10.1164/ajrccm-conference.2023.207.1_MeetingAbstracts.A2995

Female reproductive health impacts of Long COVID and associated illnesses including ME/CFS, POTS, and connective tissue disorders: a literature review

Long COVID disproportionately affects premenopausal women, but relatively few studies have examined Long COVID’s impact on female reproductive health. We conduct a review of the literature documenting the female reproductive health impacts of Long COVID which may include disruptions to the menstrual cycle, gonadal function, ovarian sufficiency, menopause, and fertility, as well as symptom exacerbation around menstruation.

Given limited research, we also review the reproductive health impacts of overlapping and associated illnesses including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), postural orthostatic tachycardia syndrome (POTS), connective tissue disorders like Ehlers-Danlos syndrome (EDS), and endometriosis, as these illnesses may help to elucidate reproductive health conditions in Long COVID.

These associated illnesses, whose patients are 70%–80% women, have increased rates of dysmenorrhea, amenorrhea, oligomenorrhea, dyspareunia, endometriosis, infertility, vulvodynia, intermenstrual bleeding, ovarian cysts, uterine fibroids and bleeding, pelvic congestion syndrome, gynecological surgeries, and adverse pregnancy complications such as preeclampsia, maternal mortality, and premature birth. Additionally, in Long COVID and associated illnesses, symptoms can be impacted by the menstrual cycle, pregnancy, and menopause.

We propose priorities for future research and reproductive healthcare in Long COVID based on a review of the literature. These include screening Long COVID patients for comorbid and associated conditions; studying the impacts of the menstrual cycle, pregnancy, and menopause on symptoms and illness progression; uncovering the role of sex differences and sex hormones in Long COVID and associated illnesses; and addressing historical research and healthcare inequities that have contributed to detrimental knowledge gaps for this patient population.

Source: Pollack Beth, von Saltza Emelia, McCorkell Lisa, Santos Lucia, Hultman Ashley, Cohen Alison K., Soares Letícia. Female reproductive health impacts of Long COVID and associated illnesses including ME/CFS, POTS, and connective tissue disorders: a literature review. Frontiers in Rehabilitation Sciences, Vol 4, 2023, ISSN=2673-6861. DOI: 10.3389/fresc.2023.1122673 https://www.frontiersin.org/articles/10.3389/fresc.2023.1122673 (Full text)

Sex differences in post-exercise fatigue and function in myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

To assess biobehavioral sex differences in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) utilizing a low burden exercise protocol, 22 females and 15 males with ME/CFS and 14 healthy controls underwent two six-min walk tests.

Fifteen daily assessments were scheduled for fatigue and function ratings and heart monitoring. Six-min walk tests were conducted on days 8 and 9. The ME/CFS group showed high self-report fatigue and impaired physical function, whereas healthy controls did not show fatigue or function abnormalities.

In patients, no significant post-exercise changes were found for heart rate variability (HRV); however, heart rate decreased in ME/CFS males from Day 14 to Day 15 (p = 0.046). Female patients showed increased fatigue (p = 0.006) after the initial walk test, but a downward slope (p = 0.008) in fatigue following the second walk test. Male patients showed a decrease in self-report work limitation in the days after exercise (p = 0.046). The healthy control group evidenced a decrease in HRV after the walk tests from Day 9-14 (p = 0.038).

This pilot study did not confirm hypotheses that females as compared to males would show slower exercise recovery on autonomic or self-report (e.g. fatigue) measures. A more exertion-sensitive test may be required to document prolonged post-exertional abnormalities in ME/CFS.

Trial registration: NCT NCT03331419.

Source: Friedberg F, Adamowicz JL, Bruckenthal P, Milazzo M, Ramjan S, Zhang X, Yang J. Sex differences in post-exercise fatigue and function in myalgic encephalomyelitis/chronic fatigue syndrome. Sci Rep. 2023 Apr 3;13(1):5442. doi: 10.1038/s41598-023-32581-w. PMID: 37012343. https://www.nature.com/articles/s41598-023-32581-w (Full text)

Sex-dependent characteristics of Neuro-Long-COVID: Data from a dedicated neurology ambulatory service

Abstract:

“Long-COVID” is a clinical entity that consists of persisting post-infectious symptoms that last for more than three months after the onset of the first acute COVID-19 symptoms. Among these, a cluster of neurological persisting symptoms defines Neuro-Long-COVID. While the debate about the pathogenesis of Long-COVID is still ongoing, sex differences have been individuated for both the acute and the chronic stage of the infection.

We conducted a retrospective study describing sex differences in a large sample of patients with Neuro-Long-COVID. Demographic and clinical data were collected in a specifically designed Neuro-Long-Covid outpatient service. Our sample included 213 patients: 151 were females and 62 were males; the mean age was similar between females (53 y, standard deviation 14) and males (55 y, standard deviation 15); no significant differences was present between the demographic features across the two groups.

Despite the prevalence of the specific chronic symptoms between male and females showed no significant differences, the total number of females accessing our service was higher than that of males, confirming the higher prevalence of Neuro-Long-COVID in female individuals. Conversely, a worse acute phase response in males rather than females was confirmed by a significant difference in the rates of acute respiratory symptoms (p = 0.008), dyspnea (p = 0.018), respiratory failure (p = 0.010) and the consequent need for ventilation (p = 0.015), together with other acute symptoms such as palpitations (p = 0.049), headache (p = 0.001) and joint pain (p = 0.049).

Taken together, these findings offer a subgroup analysis based on sex-dependent characteristics, which can support a tailored-medicine approach.

Source: Michelutti M, Furlanis G, Buoite Stella A, Bellavita G, Frezza N, Torresin G, Ajčević M, Manganotti P. Sex-dependent characteristics of Neuro-Long-COVID: Data from a dedicated neurology ambulatory service. J Neurol Sci. 2022 Jul 28;441:120355. doi: 10.1016/j.jns.2022.120355. Epub ahead of print. PMID: 35994869; PMCID: PMC9328838. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9328838/ (Full text)

Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Infectious pathogens are implicated in the etiology of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) because of the occurrence of outbreaks of the disease. While a number of different infectious agents have been associated with the onset of ME/CFS, the identity of a specific organism has been difficult to determine in individual cases. The aim of our study is to survey ME/CFS subjects for evidence of an infectious trigger and/or evidence of immune dysregulation via serological testing of plasma samples for antibodies to 122 different pathogen antigens.
Immune profiles were compared to age-, sex-, and BMI-matched controls to provide a basis for comparison. Antibody levels to individual antigens surveyed in this study do not implicate any one of the pathogens in ME/CFS, nor do they rule out common pathogens that frequently infect the US population. However, our results revealed sex-based differences in steady-state humoral immunity, both within the ME/CFS cohort and when compared to trends seen in the healthy control cohort.
Source: O’Neal AJ, Glass KA, Emig CJ, Vitug AA, Henry SJ, Shungu DC, Mao X, Levine SM, Hanson MR. Survey of Anti-Pathogen Antibody Levels in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Proteomes. 2022; 10(2):21. https://doi.org/10.3390/proteomes10020021 https://www.mdpi.com/2227-7382/10/2/21/htm (Full text)

Sexual dimorphism in a neuronal mechanism of spinal hyperexcitability across rodent and human models of pathological pain

Abstract:

The prevalence and severity of many chronic pain syndromes differ across sex, and recent studies have identified differences in immune signalling within spinal nociceptive circuits as a potential mediator. Although it has been proposed that sex-specific pain mechanisms converge once they reach neurons within the superficial dorsal horn, direct investigations using rodent and human preclinical pain models have been lacking.

Here, we discovered that in the Freund’s adjuvant in vivo model of inflammatory pain, where both male and female rats display tactile allodynia, a pathological coupling between KCC2-dependent disinhibition and N-methyl-D-aspartate receptor (NMDAR) potentiation within superficial dorsal horn neurons was observed in male but not female rats. Unlike males, the neuroimmune mediator brain-derived neurotrophic factor (BDNF) failed to downregulate inhibitory signalling elements (KCC2 and STEP61) and upregulate excitatory elements (pFyn, GluN2B and pGluN2B) in female rats, resulting in no effect of ex vivo brain-derived neurotrophic factor on synaptic NMDAR responses in female lamina I neurons. Importantly, this sex difference in spinal pain processing was conserved from rodents to humans.

As in rodents, ex vivo spinal treatment with BDNF downregulated markers of disinhibition and upregulated markers of facilitated excitation in superficial dorsal horn neurons from male but not female human organ donors. Ovariectomy in female rats recapitulated the male pathological pain neuronal phenotype, with BDNF driving a coupling between disinhibition and NMDAR potentiation in adult lamina I neurons following the prepubescent elimination of sex hormones in females. This discovery of sexual dimorphism in a central neuronal mechanism of chronic pain across species provides a foundational step towards a better understanding and treatment for pain in both sexes.

Source: Dedek A, Xu J, Lorenzo LÉ, Godin AG, Kandegedara CM, Glavina G, Landrigan JA, Lombroso PJ, De Koninck Y, Tsai EC, Hildebrand ME. Sexual dimorphism in a neuronal mechanism of spinal hyperexcitability across rodent and human models of pathological pain. Brain. 2022 Apr 29;145(3):1124-1138. doi: 10.1093/brain/awab408. PMID: 35323848; PMCID: PMC9050559. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9050559/ (Full text)

The underlying sex differences in neuroendocrine adaptations relevant to Myalgic Encephalomyelitis Chronic Fatigue Syndrome

Abstract:

Introduction: Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS) is a complex multisystem disease characterised by severe and disabling new-onset symptoms of post-exertional malaise (PEM), fatigue, brain fog, and sleep dysfunction that lasts for at least six months. Accumulating evidence suggests that sex and endocrine events have a significant influence on symptom onset and moderation of ME/CFS, with female sex being one of the most consistent and credible predictive risk factors associated with diagnosis. Such sex differences suggest sex chromosomes and sex steroids may play a part in the development of the condition or moderation of symptoms, although this has yet to be explored in detail.

Methods/aims: This narrative review outlines sex differences in ME/CFS in terms of vulnerability factors and clinical phenotype and explores the known sex differences in neuroendocrine systems affected in ME/CFS and how this may relate to disease risk, onset, pathophysiology, and potential treatment avenues.

Conclusions: There is clear evidence of a sex dimorphism with regards to prevalence (3:1 female preponderance), clinical phenotypes, and aetiological triggers prior to symptom onset of ME/CFS. Endocrinological events, particularly those throughout the female lifespan, are associated with ME/CFS and include reproductive menstrual cycle fluctuations, pregnancy, post-partum and perimenopause. Further, there is evidence for gonadal sex, adrenal stress and renal neuroendocrine systems as implicated in ME/CFS, including changes in estrogen, progesterone compounds, aldosterone, and cortisol levels, of which there are established sex differences. The broad effects of steroid hormones on the physiological systems may also speak to the diversity of ME/CFS symptomatology observed in patients. Further attention must be paid to sex, age, and steroid biology in ME/CFS.

Source: Thomas N, Gurvich C, Huang K, Gooley PR, Armstrong CW. The underlying sex differences in neuroendocrine adaptations relevant to Myalgic Encephalomyelitis Chronic Fatigue Syndrome. Front Neuroendocrinol. 2022 Apr 11:100995. doi: 10.1016/j.yfrne.2022.100995. Epub ahead of print. PMID: 35421511. https://www.sciencedirect.com/science/article/abs/pii/S0091302222000188?via%3Dihub  (Full text)

The Female-Predominant Persistent Immune Dysregulation of the Post-COVID Syndrome

Abstract:

Objective: To describe the clinical data from the first 108 patients seen in the Mayo Clinic post-COVID-19 care clinic (PCOCC).

Methods: After Institutional Review Board approval, we reviewed the charts of the first 108 patients seen between January 19, 2021, and April 29, 2021, in the PCOCC and abstracted from the electronic medical record into a standardized database to facilitate analysis. Patients were grouped into phenotypes by expert review.

Results: Most of the patients seen in our clinic were female (75%; 81/108), and the median age at presentation was 46 years (interquartile range, 37 to 55 years). All had post-acute sequelae of SARS-CoV-2 infection, with 6 clinical phenotypes being identified: fatigue predominant (n=69), dyspnea predominant (n=23), myalgia predominant (n=6), orthostasis predominant (n=6), chest pain predominant (n=3), and headache predominant (n=1). The fatigue-predominant phenotype was more common in women, and the dyspnea-predominant phenotype was more common in men. Interleukin 6 (IL-6) was elevated in 61% of patients (69% of women; P=.0046), which was more common than elevation in C-reactive protein and erythrocyte sedimentation rate, identified in 17% and 20% of cases, respectively.

Conclusion: In our PCOCC, we observed several distinct clinical phenotypes. Fatigue predominance was the most common presentation and was associated with elevated IL-6 levels and female sex. Dyspnea predominance was more common in men and was not associated with elevated IL-6 levels. IL-6 levels were more likely than erythrocyte sedimentation rate and C-reactive protein to be elevated in patients with post-acute sequelae of SARS-CoV-2 infection.

Source: Ganesh R, Grach SL, Ghosh AK, Bierle DM, Salonen BR, Collins NM, Joshi AY, Boeder ND Jr, Anstine CV, Mueller MR, Wight EC, Croghan IT, Badley AD, Carter RE, Hurt RT. The Female-Predominant Persistent Immune Dysregulation of the Post-COVID Syndrome. Mayo Clin Proc. 2022 Feb 5:S0025-6196(21)00888-0. doi: 10.1016/j.mayocp.2021.11.033. Epub ahead of print. PMID: 35135695; PMCID: PMC8817110. https://www.sciencedirect.com/science/article/pii/S0025619621008880 (Full text)

Male vs. Female Differences in Responding to Oxygen-Ozone Autohemotherapy (O 2-O 3-AHT) in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a syndrome that has fatigue as its major symptom. Evidence suggests that ozone is able to relieve ME/CFS-related fatigue in affected patients.

Objective: To evaluate whether differences exist between males and females in ozone therapy outputs in ME/CFS. (3) Methods: In total, 200 patients previously diagnosed with ME/CFS (mean age 33 ± 13 SD years) underwent treatment with oxygen-ozone autohemotherapy (O2-O3-AHT). Fatigue was investigated via an FSS 7-scoring questionnaire before and following 1 month after treatment.

Results: The Mann-Whitney test (MW test) assessed the significance of this difference (H = 13.8041, p = 0.0002), and female patients showed better outcomes than males. This difference was particularly striking in the youngest age cohort (14-29 years), and a KW test resulted in H = 7.1609, p = 0.007 for the Δ = 28.3% (males = 3.8, females = 5.3).

Conclusions: When treated with O2-O3-AHT, females respond better than males.

Source: Chirumbolo S, Valdenassi L, Franzini M, Pandolfi S, Ricevuti G, Tirelli U. Male vs. Female Differences in Responding to Oxygen-Ozone Autohemotherapy (O2-O3-AHT) in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). J Clin Med. 2021 Dec 29;11(1):173. doi: 10.3390/jcm11010173. PMID: 35011914. https://pubmed.ncbi.nlm.nih.gov/35011914/

Sex-specific plasma lipid profiles of ME/CFS patients and their association with pain, fatigue, and cognitive symptoms

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex illness which disproportionally affects females. This illness is associated with immune and metabolic perturbations that may be influenced by lipid metabolism. We therefore hypothesized that plasma lipids from ME/CFS patients will provide a unique biomarker signature of disturbances in immune, inflammation and metabolic processes associated with ME/CFS.

Methods: Lipidomic analyses were performed on plasma from a cohort of 50 ME/CFS patients and 50 controls (50% males and similar age and ethnicity per group). Analyses were conducted with nano-flow liquid chromatography (nLC) and high-performance liquid chromatography (HPLC) systems coupled with a high mass accuracy ORBITRAP mass spectrometer, allowing detection of plasma lipid concentration ranges over three orders of magnitude. We examined plasma phospholipids (PL), neutral lipids (NL) and bioactive lipids in ME/CFS patients and controls and examined the influence of sex on the relationship between lipids and ME/CFS diagnosis.

Results: Among females, levels of total phosphatidylethanolamine (PE), omega-6 arachidonic acid-containing PE, and total hexosylceramides (HexCer) were significantly decreased in ME/CFS compared to controls. In males, levels of total HexCer, monounsaturated PE, phosphatidylinositol (PI), and saturated triglycerides (TG) were increased in ME/CFS patients compared to controls. Additionally, omega-6 linoleic acid-derived oxylipins were significantly increased in male ME/CFS patients versus male controls. Principal component analysis (PCA) identified three major components containing mostly PC and a few PE, PI and SM species-all of which were negatively associated with headache and fatigue severity, irrespective of sex. Correlations of oxylipins, ethanolamides and ME/CFS symptom severity showed that lower concentrations of these lipids corresponded with an increase in the severity of headaches, fatigue and cognitive difficulties and that this association was influenced by sex.

Conclusion: The observed sex-specific pattern of dysregulated PL, NL, HexCer and oxylipins in ME/CFS patients suggests a possible role of these lipids in promoting immune dysfunction and inflammation which may be among the underlying factors driving the clinical presentation of fatigue, chronic pain, and cognitive difficulties in ill patients. Further evaluation of lipid metabolism pathways is warranted to better understand ME/CFS pathogenesis.

Source: Nkiliza A, Parks M, Cseresznye A, Oberlin S, Evans JE, Darcey T, Aenlle K, Niedospial D, Mullan M, Crawford F, Klimas N, Abdullah L. Sex-specific plasma lipid profiles of ME/CFS patients and their association with pain, fatigue, and cognitive symptoms. J Transl Med. 2021 Aug 28;19(1):370. doi: 10.1186/s12967-021-03035-6. PMID: 34454515. https://pubmed.ncbi.nlm.nih.gov/34454515/