Plasma taurine level is linked to symptom burden and clinical outcomes in post-COVID condition

Abstract:

Background: A subset of individuals (10-20%) experience post-COVID condition (PCC) subsequent to initial SARS-CoV-2 infection, which lacks effective treatment. PCC carries a substantial global burden associated with negative economic and health impacts. This study aims to evaluate the association between plasma taurine levels with self-reported symptoms and adverse clinical outcomes in patients with PCC.

Methods and findings: We analyzed the plasma proteome and metabolome of 117 individuals during their acute COVID-19 hospitalization and at the convalescence phase six-month post infection. Findings were compared with 28 age and sex-matched healthy controls. Plasma taurine levels were negatively associated with PCC symptoms and correlated with markers of inflammation, tryptophan metabolism, and gut dysbiosis. Stratifying patients based on the trajectories of plasma taurine levels during six-month follow-up revealed a significant association with adverse clinical events. Increase in taurine levels during the transition to convalescence were associated with a reduction in adverse events independent of comorbidities and acute COVID-19 severity. In a multivariate analysis, increased plasma taurine level between acute and convalescence phase was associated with marked protection from adverse clinical events with a hazard ratio of 0.13 (95% CI: 0.05-0.35; p<0.001).

Conclusions: Taurine emerges as a promising predictive biomarker and potential therapeutic target in PCC. Taurine supplementation has already demonstrated clinical benefits in various diseases and warrants exploration in large-scale clinical trials for alleviating PCC.

Source: Khoramjoo M, Wang K, Srinivasan K, Gheblawi M, Mandal R, Rousseau S, Wishart D, Prasad V, Richer L, Cheung AM, Oudit GY. Plasma taurine level is linked to symptom burden and clinical outcomes in post-COVID condition. PLoS One. 2024 Jun 5;19(6):e0304522. doi: 10.1371/journal.pone.0304522. PMID: 38837993; PMCID: PMC11152273. https://pmc.ncbi.nlm.nih.gov/articles/PMC11152273/ (Full text)

The effects of 3-month supplementation with synbiotic on patient-reported outcomes, exercise tolerance, and brain and muscle metabolism in adult patients with post-COVID-19 chronic fatigue syndrome (STOP-FATIGUE): a randomized Placebo-controlled clinical trial

Abstract:

Purpose: Considering the observed gastrointestinal issues linked to post-COVID-19 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), beneficially modulating the gut microbiota could offer a safe, cost-effective nutritional strategy. This trial aimed to evaluate the effects of medium-term synbiotic supplementation on patient-reported outcomes, exercise tolerance, and tissue metabolism in patients with post-COVID-19 ME/CFS.

Methods: Between September 2022 and December 2023, we investigated the impact of 3-month supplementation with a synbiotic mixture including L. rhamnosus DSM 32550, Humiome® L. plantarum DSM 34532, B. lactis DSM 32269, B. longum DSM 32946, fructooligosaccharides and zinc, on predetermined primary and secondary outcome measures in twenty six post-COVID-19 ME/CFS patients utilizing a parallel-group, randomized, placebo-controlled, double-blind design.

Results: Both the synbiotic and placebo intake resulted in a significant reduction in general fatigue after 3 months compared to the baseline values (P ≤ 0.05). This was accompanied by a significant interaction effect (time vs. treatment) for post-exercise malaise (P = 0.02), with synbiotic superior to placebo to attenuate post-exercise malaise. The synbiotic also demonstrated a significant advantage over placebo in increasing choline levels at the thalamus (P = 0.02), and creatine levels at left frontal white matter (P = 0.05) and left frontal grey matter (P = 0.04).

Conclusion: Taking the synbiotic mixture for three months improves tissue metabolism and mitigates clinical features of post-COVID-19 fatigue syndrome. The presented data show promise in addressing the widespread issue of ME/CFS following the COVID-19 pandemic; however, further validation is needed before endorsing the synbiotics within this clinical context. The study is registered at ClinicalTrials.gov (NCT06013072).

Source: Ranisavljev M, Stajer V, Todorovic N, Ostojic J, Cvejic JH, Steinert RE, Ostojic SM. The effects of 3-month supplementation with synbiotic on patient-reported outcomes, exercise tolerance, and brain and muscle metabolism in adult patients with post-COVID-19 chronic fatigue syndrome (STOP-FATIGUE): a randomized Placebo-controlled clinical trial. Eur J Nutr. 2024 Nov 26;64(1):28. doi: 10.1007/s00394-024-03546-0. PMID: 39592468. https://pubmed.ncbi.nlm.nih.gov/39592468/

Red Blood Cell Morphology Is Associated with Altered Hemorheological Properties and Fatigue in Patients with Long COVID

Simple Summary:
SARS-CoV-2 alters the properties of oxygen-carrying red blood cells (RBCs) through a possible deterioration of hemorheological properties, such as aggregation and deformability. However, long-term changes in these properties and a possible association with morphological abnormalities remain unknown. Therefore, this study aims to investigate changes in the above-mentioned RBC properties in Long-COVID (LC). Venous blood was collected from n = 30 diagnosed LC and n = 30 non-Long-COVID controls (non-LC). Hematological parameters were measured, as well as the aggregation, deformability, and morphology of the RBCs and the mechanical sensitivity index (MS), which reflects the functional capacity of RBCs to deform. The results indicate that hematological parameters were not altered in LC. However, LC showed higher overall aggregation parameters. RBC deformability was higher in LC compared to non-LC; however, MS was limited in this group. LC showed a higher percentage of RBCs with abnormal shapes, which was related to MS and to fatigue, which is considered the leading symptom of LC. It is concluded that the symptoms of LC and changes in the blood flow determining the properties of RBCs are related to the morphological changes in RBCs. Future studies should investigate the underlying causes in order to develop appropriate therapies for this relatively new disease.
Abstract:

Background: SARS-CoV-2 infection adversely affects rheological parameters, particularly red blood cell (RBC) aggregation and deformability, but whether these changes persist in patients suffering from Long-COVID (LC) and whether these changes are related to RBC morphology remain unknown.
Methods: Venous blood was collected from n = 30 diagnosed LC patients and n = 30 non-LC controls and RBC deformability, RBC aggregation, and hematological parameters were measured. In addition, RBCs were examined microscopically for morphological abnormalities. The mechanical sensitivity index (MS) was assessed in n = 15 LC and n = 15 non-LC samples.
Results: Hematological parameters did not differ between the groups. However, LC showed higher aggregation-related parameters. Although RBC deformability was higher in LC, MS, reflecting the functional capacity to deform, was limited in this group. RBCs from LC showed significantly more morphological abnormalities. The extent of morphological abnormalities correlated with MS and the FACIT-Fatigue score of the LC patients.
Conclusion: RBCs from LC show a high degree of morphological abnormalities, which might limit the blood flow determining RBC properties and also be related to fatigue symptomatology in LC. Approaches are now needed to understand the underlying cause of these alterations and to ameliorate these permanent changes.
Source: Grau M, Presche A, Krüger A-L, Bloch W, Haiduk B. Red Blood Cell Morphology Is Associated with Altered Hemorheological Properties and Fatigue in Patients with Long COVID. Biology. 2024; 13(11):948. https://doi.org/10.3390/biology13110948 https://www.mdpi.com/2079-7737/13/11/948 (Full text)

Cognitive impact and brain structural changes in long COVID patients: a cross-sectional MRI study two years post infection in a cohort from Argentina

Abstract:

Objective: Long COVID is a condition characterised by persistent symptoms after a SARS-CoV-2 infection, with neurological manifestations being particularly frequent. Existing research suggests that long COVID patients not only report cognitive symptoms but also exhibit measurable cognitive impairment. Neuroimaging studies have identified structural alterations in brain regions linked to cognitive functions. However, most of these studies have focused on patients within months of their initial infection. This study aims to explore the longer-term cognitive effects and brain structural changes in long COVID patients, approximately two years post-infection, in a cohort from San Martín, Buenos Aires, Argentina.

Methods: We conducted a cross-sectional study involving 137 participants: 109 with long COVID symptoms and 28 healthy controls. The participants underwent an initial clinical assessment, completed a structured questionnaire and standardised scales, underwent a cognitive assessment, and had a brain MRI scan. Structural MRI images were processed via FreeSurfer and FSL to obtain volumetric measures for subcortical and cortical regions, along with regional cortical thickness. Differences between groups for these variables were analysed using ANCOVA, with permutation tests applied to correct for multiple comparisons.

Results: Long COVID patients reported persistent cognitive symptoms such as memory problems and brain fog, with higher levels of fatigue and reduced quality of life compared to controls. Despite subjective cognitive complaints, cognitive tests did not reveal significant differences between groups, except for the TMT-A (p = 0.05). MRI analysis revealed decreased volume in the cerebellum (p = 0.03), lingual gyrus (p = 0.04), and inferior parietal regions (p = 0.03), and reduced cortical thickness in several areas, including the left and right postcentral gyri (p = 0.02, p = 0.03) and precuneus (p = 0.01, p = 0.02).

Conclusions: This study highlights the enduring impact of long COVID on quality of life and physical activity, with specific brain structural changes identified two years post-infection. Although cognitive tests did not show clear impairment, the observed brain atrophy and significant reduction in quality of life emphasize the need for comprehensive interventions and further longitudinal studies to understand the long-term effects of long COVID on cognition and brain health.

Source: Cataldo SA, Micciulli A, Margulis L, Cibeyra M, Defeo S, Horovitz SG, Martino A, Melano R, Mena M, Parisi F, Santoro D, Sarmiento F, Belzunce MA. Cognitive impact and brain structural changes in long COVID patients: a cross-sectional MRI study two years post infection in a cohort from Argentina. BMC Neurol. 2024 Nov 18;24(1):450. doi: 10.1186/s12883-024-03959-8. PMID: 39558250; PMCID: PMC11572126. https://pmc.ncbi.nlm.nih.gov/articles/PMC11572126/ (Full text)

Postural orthostatic tachycardia syndrome and other common autonomic disorders are not functional neurologic disorders

Introduction:

In the past 4 years of COVID-19 and Long COVID, a renewed interest in postural orthostatic tachycardia syndrome (POTS) and other autonomic disorders brought to light a common misconception that these disorders are based in or are associated with functional neurologic disorder (FND). Recently, one narrative review attempted to link autonomic disorders and autonomic nervous system dysfunction with symptoms of FND (1). Others have similarly suggested that Long COVID may be based in functional or somatic etiology (25). As medical professionals with expertise in autonomic disorders, we would like to emphasize the distinction between autonomic disorders, autonomic symptoms and FND in order to ensure that appropriate diagnostic and therapeutic pathways are implemented by clinicians.

Source: Blitshteyn S, Treisman GJ, Ruhoy IS, Saperstein DS, Schofield JR, Goodman BP, Davenport TE, Cutchins AC and Grubb BP (2024) Postural orthostatic tachycardia syndrome and other common autonomic disorders are not functional neurologic disorders. Front. Neurol. 15:1490744. doi: 10.3389/fneur.2024.1490744 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2024.1490744/full (Full text)

On the Prevalence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome after a SARS-CoV-2 infection

Introduction:

There is an increasing body of evidence connecting the post-acute SARS-CoV-2 condition (PASC, commonly known as long COVID) to Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a debilitating disease of unknown cause characterized by persistent and unexplained fatigue, post-exertional malaise (PEM), among other symptoms. This connection implies that, in the clinic, some PASC cases comply with the official case definitions of ME/CFS. As such, there is a necessity to quantify the burden of ME/CFS among the PASC population in order to delineate effective healthcare interventions for the benefit of these patients who are often neglected or, in some extreme cases, stigmatized by medical staff and society.
To answer this urgent research question, Dehlia and Guthridge performed a systematic review and meta-analysis of recent data on PASC adults and reported an ME/CFS prevalence estimate of 51% (95% CI, 42%-60%); this systematic review and meta-analysis will be referred to as PASC-ME/CFS study. In the present Letter to Editor, we aimed to discuss the reliability of this estimate using the research protocol from the European Network on ME/CFS (EUROMENE) for systematic reviews and meta-analysis on the epidemiology burden of ME/CFS in Europe.

Source: Sepúlveda N, Westermeier F. On the Prevalence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome after a SARS-CoV-2 infection. J Infect. 2024 Nov 16:106353. doi: 10.1016/j.jinf.2024.106353. Epub ahead of print. PMID: 39557089. Sepúlveda N, Westermeier F. On the Prevalence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome after a SARS-CoV-2 infection. J Infect. 2024 Nov 16:106353. doi: 10.1016/j.jinf.2024.106353. Epub ahead of print. PMID: 39557089. https://www.journalofinfection.com/article/S0163-4453(24)00288-3/fulltext (Full text)

Initiating Long Covid RECOVERy

Introduction:

The coronavirus disease 2019 (COVID-19) pandemic paralyzed the United States, rendering thousands critically ill and ultimately killing more than 1 million Americans. Many survivors, particularly those with adult respiratory distress syndrome, required prolonged rehabilitation. Many more people, including those who did not require hospitalization for their acute illness, presented with a host of other persistent, disabling symptoms. The latter condition was termed “Long Covid” and turned out to be the most prevalent postacute sequelae of the COVID-19 pandemic.

The symptom complex that characterizes Long Covid resembles that seen in other infection-associated chronic conditions, notably overlapping with those of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Overlapping symptoms include fatigue, unrefreshing sleep, neurocognitive dysfunction characterized by impaired executive function, exercise intolerance, fluctuating heart rate and sense of dizziness particularly in the upright position, and postexertional malaise, a signature symptom of ME/CFS. The drivers of these conditions remain unknown, and no treatments have proven effective. Data suggest that many individuals with Long Covid may return to health months or years after onset, but debilitating symptoms and unknown long-term outcomes remain in too many people. Of greatest concern is that, for some individuals, Long Covid may last a lifetime.

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Source: Marrazzo J, Gibbons GH, Koroshetz W. Initiating Long Covid RECOVERy. Sci Transl Med. 2024 Nov 13;16(773):eadr9971. doi: 10.1126/scitranslmed.adr9971. Epub 2024 Nov 13. PMID: 39536123. https://www.science.org/doi/10.1126/scitranslmed.adr9971 (Full text)

Trajectories of functional limitations, health-related quality of life and societal costs in individuals with long COVID: a population-based longitudinal cohort study

Abstract:

Objectives: To examine trajectories of functional limitations, fatigue, health-related quality of life (HRQL) and societal costs of patients referred to long COVID clinics.

Design: A population-based longitudinal cohort study using real-time user data.

Setting: 35 specialised long COVID clinics in the UK.

Participants: 4087 adults diagnosed with long COVID in primary or secondary care deemed suitable for rehabilitation and registered in the Living With Covid Recovery (LWCR) programme between 4 August 2020 and 5 August 2022.

Main outcome measures: Generalised linear mixed models were fitted to estimate trajectories of functional limitations, using the Work and Social Adjustment Scale (WSAS); scores of ≥20 indicate moderately severe limitations. Other outcomes included fatigue using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) reversed score (scores of ≥22 indicate impairment), HRQL using the EQ-5D-5L, and long COVID-related societal costs, encompassing healthcare costs and productivity losses.

Results: The mean WSAS score at 6 months after registration in the LWCR was 19.1 (95% CI 18.6, 19.6), with 46% of the participants (95% CI 40.3%, 52.4%) reporting a WSAS score above 20 (moderately severe or worse impairment). The mean change in the WSAS score over the 6-month period was -0.86 (95% CI -1.32, -0.41). The mean reversed FACIT-F score at 6 months was 29.1 (95% CI 22.7, 35.5) compared with 32.0 (95% CI 31.7, 32.3) at baseline. The mean EQ-5D-5L score remained relatively constant between baseline (0.63, 95% CI 0.62, 0.64) and 6 months (0.64, 95% CI 0.59, 0.69). The monthly societal cost per patient related to long COVID at 6 months was £931, mostly driven by the costs associated with working days lost.

Conclusions: Individuals referred to long COVID clinics in the UK reported small improvements in functional limitations, fatigue, HRQL and ability to work within 6 months of registering in the LWCR programme.

Source: Wang J, Goodfellow H, Walker S, Blandford A, Pfeffer P, Hurst JR, Sunkersing D, Bradbury K, Robson C, Henley W, Gomes M. Trajectories of functional limitations, health-related quality of life and societal costs in individuals with long COVID: a population-based longitudinal cohort study. BMJ Open. 2024 Nov 13;14(11):e088538. doi: 10.1136/bmjopen-2024-088538. PMID: 39537389. https://bmjopen.bmj.com/content/14/11/e088538 (Full text)

Blood virome research in myalgic encephalomyelitis/chronic fatigue syndrome: challenges and opportunities

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease with a complex clinical presentation and an unknown etiology. Various viral infections have been proposed as potential triggers of ME/CFS onset, but no specific pathogen has been identified in all cases of postinfectious ME/CFS.

The symptomatology of the postacute sequelae of SARS-CoV-2, or long COVID, mirrors that of ME/CFS, with nearly half of long COVID patients meeting ME/CFS diagnostic criteria. The influx of newly diagnosed patients has reinvigorated interest in ME/CFS pathogenesis research, with an emphasis on viral triggers.

This review summarizes the current understanding of ME/CFS research on viral triggers, including blood virome screening studies. To further elucidate the molecular basis of ME/CFS, there is a need to develop innovative bioinformatics tools capable of analyzing complex virome data and integrating multiomics information.

Source: Obraitis D, Li D. Blood virome research in myalgic encephalomyelitis/chronic fatigue syndrome: challenges and opportunities. Curr Opin Virol. 2024 Nov 12:101437. doi: 10.1016/j.coviro.2024.101437. Epub ahead of print. PMID: 39537445. https://www.sciencedirect.com/science/article/pii/S1879625724000518 (Full text)

Overlapping conditions in Long COVID at a multisite academic center

Abstract:

Background: Many patients experience persistent symptoms after COVID-19, a syndrome referred to as Long COVID (LC). The goal of this study was to identify novel new or worsening comorbidities self-reported in patients with LC.

Methods: Patients diagnosed with LC (n = 732) at the Mayo Long COVID Care Clinic in Rochester, Minnesota and Jacksonville, Florida were sent questionnaires to assess the development of new or worsening comorbidities following COVID-19 compared to patients with SARS-CoV-2 that did not develop LC (controls). Both groups were also asked questions screening for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), generalized joint hypermobility (GJH) and orthostatic intolerance. 247 people with LC (33.7%) and 40 controls (50%) responded to the surveys.

Results: In this study LC patients averaged 53 years of age and were predominantly White (95%) women (75%). The greatest prevalence of new or worsening comorbidities following SARS-CoV-2 infection in patients with LC vs. controls reported in this study were pain (94.4% vs. 0%, p < 0.001), neurological (92.4% vs. 15.4%, p < 0.001), sleep (82.8% vs. 5.3%, p < 0.001), skin (69.8% vs. 0%, p < 0.001), and genitourinary (60.6% vs. 25.0%, p = 0.029) issues. 58% of LC patients screened positive for ME/CFS vs. 0% of controls (p < 0.001), 27% positive for GJH compared to 10% of controls (p = 0.026), and a positive average score of 4.0 on orthostatic intolerance vs. 0 (p < 0.001). The majority of LC patients with ME/CFS were women (77%).

Conclusion: We found that comorbidities across 12 surveyed categories were increased in patients following SARS-CoV-2 infection. Our data also support the overlap of LC with ME/CFS, GJH, and orthostatic intolerance. We discuss the pathophysiologic, research, and clinical implications of identifying these conditions with LC.

Source: Grach SL, Dudenkov DV, Pollack B, Fairweather D, Aakre CA, Munipalli B, Croghan IT, Mueller MR, Overgaard JD, Bruno KA, Collins NM, Li Z, Hurt RT, Tal MC, Ganesh R, Knight DTR. Overlapping conditions in Long COVID at a multisite academic center. Front Neurol. 2024 Oct 25;15:1482917. doi: 10.3389/fneur.2024.1482917. PMID: 39524912; PMCID: PMC11543549. https://pmc.ncbi.nlm.nih.gov/articles/PMC11543549/ (Full text)