Quantitative Proteomics of COVID-19 Recovered Patients Identifies Long-Term Changes in Sperm Proteins Leading to Cellular Stress in Spermatozoa

Abstract:

Following an initial recovery, COVID-19 survivors struggle with a spectrum of persistent medical complications, including fatigue, breathlessness, weight loss, hair loss, and attention deficits. Additionally, there is growing evidence of adverse effects of COVID-19 on the male reproductive system. This investigation seeks to understand the long-term ramifications on male fertility by examining hormonal profiles, semen parameters, and sperm proteome of recovered COVID-19 patients compared to controls.

The serum hormone profiles between the two groups showed minimal variations except for prolactin, cortisol, and testosterone levels. Testosterone levels were slightly lower, while prolactin and cortisol were elevated in COVID-19 cases compared to controls.

Though semen parameters exhibited no significant disparities between the COVID-19 and control groups, quantitative proteomics analysis revealed changes in sperm proteins. It identified 190 differentially expressed proteins, of which 161 were upregulated and 29 downregulated in COVID-19 cases.

Western blotting analysis validated the differential expression of serpin B4 and calpain 2. Bioinformatics analysis signifies cellular stress in the spermatozoa of COVID-19 recovered patients and thus, SOD and MDA levels in semen were measured. MDA levels were found to be significantly elevated, indicating lipid peroxidation in COVID-19 samples.

While the effects of COVID-19 on semen parameters may exhibit a potential for reversal within a short duration, the alterations it inflicts on sperm proteome are persisting consequences on male fertility. This study paves the path for further research and emphasizes the significance of comprehending the complex molecular processes underlying the long-term consequences of COVID-19 on male reproductive health.

Source: Chopra P, Tomar AK, Thapliyal A, Ranjan P, Datta SK, Yadav S. Quantitative Proteomics of COVID-19 Recovered Patients Identifies Long-Term Changes in Sperm Proteins Leading to Cellular Stress in Spermatozoa. Reprod Sci. 2024 Apr 24. doi: 10.1007/s43032-024-01560-5. Epub ahead of print. PMID: 38658489. https://pubmed.ncbi.nlm.nih.gov/38658489/

Blood transcriptomic analyses reveal persistent SARS-CoV-2 RNA and candidate biomarkers in post-COVID-19 condition

Abstract:

With an estimated 65 million individuals affected by post-COVID-19 condition (also known as long COVID), non-invasive biomarkers are direly needed to guide clinical management. To address this pressing need, we used blood transcriptomics in a general practice-based case-control study. Individuals with long COVID were diagnosed according to WHO criteria, and validated clinical scales were used to quantify patient-reported outcomes.

Whole blood samples were collected from 48 individuals with long COVID and 12 control individuals matched for age, sex, time since acute COVID-19, severity, vaccination status, and comorbidities (appendix 1 p 2). Digital transcriptomic analysis was performed using the nCounter (Nanostring Technologies, Seattle, WA, USA) platform, as described for critical COVID-19.

Consequently, 212 genes were identified to be differentially expressed between individuals with long COVID and controls (figure A), of which 70 remained significant after adjustment for false discovery rate correction (appendix 1). Several viral RNAs were upregulated: nucleocapsid, ORF7a, ORF3a, Mpro (a nirmatrelvir plus ritonavir [Paxlovid] target), and antisense ORF1ab RNA. Specifically, the upregulation of antisense ORF1ab RNA suggests ongoing viral replication. SARS-CoV-2-related host RNAs (ACE2/TMPRSS2 receptors, DPP4/FURIN proteases) and RNAs prototypical for memory B-cells and platelets were also upregulated (figure A).

Multivariable logistic regression identified antisense SARS-CoV-2 and FYN RNA concentrations as independent predictors of long COVID (corrected for age and sex; appendix 1 p 2). Receiver operating characteristic curve analysis showed significant discrimination (area under curve [AUC] 0·94, 95% CI 0·86–1·00) between individuals with long COVID (n=48) and controls (n=12), with 93·8% sensitivity and 91·7% specificity (figure B).

Single biomarkers antisense SARS-CoV-2 (AUC 0·78, 0·65–0·90) and FYN RNA (AUC 0·89, 0·79–0·99) were significant predictors with lower sensitivity (52·1% and 72·9%, respectively) but similar specificity (91·7% and 100%, respectively; figure B). Upon summarising transcriptomic results into biological pathways, we found significantly decreased immunometabolism in individuals with long COVID, which was negatively correlated with the blood viral load (appendix 1 p 3).

A qualitative analysis of individual SARS-CoV-2 transcript positivity revealed significant differences between individuals with long COVID and controls for antisense (65% vs 25%), ORF7a (60% vs 25%), and nucleocapsid (50% vs 8%) RNAs (figure C). Similarly, the SARS-CoV-2 transcript positivity with respect to the total blood viral load was also significantly different (60% vs 8%).

By use of multivariable logistic regression, we found that age and sex were not associated with the distinction between a low and high viral RNA load status. Conversely, the number of comorbidities (odds ratio [OR] 1·61, 95% CI 1·14–2·49) and COVID vaccine doses (OR 0·36, 0·14–0·79) emerged as independent predictors of distinguishing between low and high viral RNA load status (appendix 2).

We found that viral and immune parameters, such as the antisense Orf1ab RNA concentrations and immunometabolism score, were also linked to the patient-reported anxiety or depression score. Individuals classified as having severe anxiety or depression (with a score of 4 and 5) displayed significantly higher antisense RNA concentrations and lower immunometabolism scores (p<0·05) than those categorised as mild (with scores of 1–3; figure D).

In conclusion, the associations among persistent viral RNA, immunometabolism, and patient-reported outcomes provide mechanistic insights for addressing the challenges posed by long COVID.

Source: Menezes SM, Jamoulle M, Carletto MP, Moens L, Meyts I, Maes P, Van Weyenbergh J. Blood transcriptomic analyses reveal persistent SARS-CoV-2 RNA and candidate biomarkers in post-COVID-19 condition. Lancet Microbe. 2024 Apr 24:S2666-5247(24)00055-7. doi: 10.1016/S2666-5247(24)00055-7. Epub ahead of print. PMID: 38677304. https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(24)00055-7/fulltext (Full text)

SARS-CoV-2 Mitochondrial Metabolic and Epigenomic Reprogramming in COVID-19

Abstract:

To determine the effects of SARS-CoV-2 infection on cellular metabolism, we conducted an exhaustive survey of the cellular metabolic pathways modulated by SARS-CoV-2 infection and confirmed their importance for SARS-CoV-2 propagation by cataloging the effects of specific pathway inhibitors. This revealed that SARS-CoV-2 strongly inhibits mitochondrial oxidative phosphorylation (OXPHOS) resulting in increased mitochondrial reactive oxygen species (mROS) production.

The elevated mROS stabilizes HIF-1α which redirects carbon molecules from mitochondrial oxidation through glycolysis and the pentose phosphate pathway (PPP) to provide substrates for viral biogenesis. mROS also induces the release of mitochondrial DNA (mtDNA) which activates innate immunity. The restructuring of cellular energy metabolism is mediated in part by SARS-CoV-2 Orf8 and Orf10 whose expression restructures nuclear DNA (nDNA) and mtDNA OXPHOS gene expression.

These viral proteins likely alter the epigenome, either by directly altering histone modifications or by modulating mitochondrial metabolite substrates of epigenome modification enzymes, potentially silencing OXPHOS gene expression and contributing to long-COVID.

Source: Guarnieri JW, Haltom JA, Albrecht YES, Lie T, Olali AZ, Widjaja GA, Ranshing SS, Angelin A, Murdock D, Wallace DC. SARS-CoV-2 Mitochondrial Metabolic and Epigenomic Reprogramming in COVID-19. Pharmacol Res. 2024 Apr 11:107170. doi: 10.1016/j.phrs.2024.107170. Epub ahead of print. PMID: 38614374. https://www.sciencedirect.com/science/article/pii/S1043661824001142 (Full text)

Long COVID-19 and Peripheral Serotonin: A Commentary and Reconsideration

Abstract:

We believe there are serious problems with a recently published and highly publicized paper entitled “Serotonin reduction in post-acute sequelae of viral infection.” The blood centrifugation procedure reportedly used by Wong et al would produce plasma that is substantially (over 95%) depleted of platelets. Given this, their published mean plasma serotonin values of 1.2 uM and 2.4 uM for the control/contrast groups appear to be at least 30 to 60 times too high and should be disregarded. The plasma serotonin values reported for the long COVID and viremia patients also should be disregarded, as should any comparisons to the control/contrast groups.

We also note that the plasma serotonin means for the two control/contrast groups are not in good agreement. In the “Discussion” section, Wong et al state that their results tend to support the use of selective serotonin reuptake inhibitors (SSRIs) for the treatment of COVID-19, and they encourage further clinical trials of SSRIs. While they state that, “Our animal models demonstrate that serotonin levels can be restored and memory impairment reversed by precursor supplementation or SSRI treatment”, it should be noted that no data are presented showing an increase or restoration in circulating serotonin with SSRI administration.

In fact, one would expect a marked decline in platelet serotonin due to SSRIs’ effective inhibition of the platelet serotonin transporter. Wong et al hypothesize that problems of long COVID arise from too little peripheral serotonin. However, given the frequent presence of a hyperaggregation state in long COVID, and the known augmenting effects of platelet serotonin on platelet aggregation, it is plausible to suggest that reductions in platelet serotonin might be associated with a lessening of the cardiovascular sequelae of COVID-19.

Source: Anderson GM, Cook EH, Blakely RD, Sutcliffe JS, Veenstra-VanderWeele J. Long COVID-19 and Peripheral Serotonin: A Commentary and Reconsideration. J Inflamm Res. 2024 Apr 11;17:2169-2172. doi: 10.2147/JIR.S456000. PMID: 38628604; PMCID: PMC11019386. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11019386/ (Full text)

Recovery of neurophysiological measures in post-COVID fatigue: a 12-month longitudinal follow-up study

Abstract:

One of the major consequences of the COVID-19 pandemic has been the significant incidence of persistent fatigue following resolution of an acute infection (i.e. post-COVID fatigue). We have shown previously that, in comparison to healthy controls, those suffering from post-COVID fatigue exhibit changes in muscle physiology, cortical circuitry, and autonomic function. Whether these changes preceded infection, potentially predisposing people to developing post-COVID fatigue, or whether the changes were a consequence of infection was unclear.

Here we present results of a 12-month longitudinal study of 18 participants from the same cohort of post-COVID fatigue sufferers to investigate these correlates of fatigue over time. We report improvements in self-perception of the impact of fatigue via questionnaires, as well as significant improvements in objective measures of peripheral muscle fatigue and autonomic function, bringing them closer to healthy controls. Additionally, we found reductions in muscle twitch tension rise times, becoming faster than controls, suggesting that the improvement in muscle fatigability might be due to a process of adaptation rather than simply a return to baseline function.

Source: Maffitt NJ, Germann M, Baker AME, Baker MR, Baker SN, Soteropoulos DS. Recovery of neurophysiological measures in post-COVID fatigue: a 12-month longitudinal follow-up study. Sci Rep. 2024 Apr 17;14(1):8874. doi: 10.1038/s41598-024-59232-y. PMID: 38632415; PMCID: PMC11024107. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024107/ (Full text)

Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19

Abstract:

Objectives: To report a case-control study of new-onset small fiber neuropathy (SFN) after COVID-19 with invasive cardiopulmonary exercise testing (iCPET). SFN is a critical objective finding in long COVID and amenable to treatment.

Methods: A retrospective chart review was conducted on patients seen in the NeuroCOVID Clinic at Yale who developed new-onset SFN after a documented COVID-19 illness. We collected demographics, symptoms, skin biopsy, iCPET testing, treatments, and clinical response to treatment or no intervention.

Results: Sixteen patients were diagnosed with SFN on skin biopsy (median age 47, 75% female, 75% White). 92% of patients reported postexertional malaise characteristic of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and 7 patients underwent iCPET, which demonstrated neurovascular dysregulation and dysautonomia consistent with ME/CFS. Nine patients underwent treatment with IVIG, and 7 were not treated with IVIG. The IVIG group experienced significant clinical response in their neuropathic symptoms (9/9) compared with those who did not receive IVIG (3/7; p = 0.02).

Discussion: Here, we present preliminary evidence that after COVID-19, SFN is responsive to treatment with IVIG and linked with neurovascular dysregulation and dysautonomia on iCPET. A larger clinical trial is indicated to further demonstrate the clinical utility of IVIG in treating postinfectious SFN.

Classification of evidence: This study provides Class III evidence. It is a retrospective cohort study.

Source: McAlpine L, Zubair AS, Joseph P, Spudich S. Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19. Neurol Neuroimmunol Neuroinflamm. 2024 May;11(3):e200244. doi: 10.1212/NXI.0000000000200244. Epub 2024 Apr 17. PMID: 38630952. https://www.neurology.org/doi/10.1212/NXI.0000000000200244 (Full text)

Exploring Cognitive Dysfunction in Long COVID Patients: Eye Movement Abnormalities and Frontal-Subcortical Circuits Implications via Eye-Tracking and Machine Learning

Abstract:

Background: Cognitive dysfunction is regarded as one of the most severe aftereffects following coronavirus disease 2019 (COVID-19). Eye movements, controlled by various brain regions, including the dorsolateral prefrontal cortex and frontal-thalamic circuits, offer a potential metric for evaluating cognitive dysfunction. We aimed to examine the utility of eye movement measurements in identifying cognitive impairments in long COVID patients.

Methods: We recruited 40 long COVID patients experiencing subjective cognitive complaints and 40 healthy controls and used a certified eye-tracking medical device to record saccades and antisaccades. Machine learning was applied to enhance the analysis of eye movement data.

Results: Patients did not differ from the healthy controls regarding age, sex, and years of education. However, the patients’ Montreal Cognitive Assessment total score was significantly lower than healthy controls. Most eye movement parameters were significantly worse in patients: the latencies, gain, and velocity of visually and memory-guided saccades, the number of correct memory saccades, the latencies and duration of reflexive saccades, and the number of errors in the antisaccade test. Machine learning permitted distinguishing between long COVID patients experiencing subjective cognitive complaints and healthy controls.

Conclusion: Our findings suggest impairments in frontal subcortical circuits in long COVID patients experiencing subjective cognitive complaints. Eye-tracking, combined with machine learning, offers a novel, efficient way to assess and monitor long COVID patients’ cognitive dysfunctions, suggesting its utility in clinical settings for early detection and personalized treatment strategies. Further research is needed to determine the long-term implications of these findings and the reversibility of cognitive dysfunctions.

Source: Benito-León J, Lapeña J, García-Vasco L, Cuevas C, Viloria-Porto J, Calvo-Córdoba A, Arrieta-Ortubay E, Ruiz-Ruigómez M, Sánchez-Sánchez C, García-Cena C. Exploring Cognitive Dysfunction in Long COVID Patients: Eye Movement Abnormalities and Frontal-Subcortical Circuits Implications via Eye-Tracking and Machine Learning. Am J Med. 2024 Apr 5:S0002-9343(24)00217-1. doi: 10.1016/j.amjmed.2024.04.004. Epub ahead of print. PMID: 38583751. https://pubmed.ncbi.nlm.nih.gov/38583751/

Long COVID and post-acute sequelae of SARS-CoV-2 pathogenesis and treatment: A Keystone Symposia report

Abstract:

In 2023, the Keystone Symposia held the first international scientific conference convening research leaders investigating the pathology of post-acute sequelae of COVID-19 (PASC) or Long COVID, a growing and urgent public health priority. In this report, we present insights from the talks and workshops presented during this meeting and highlight key themes regarding what researchers have discovered regarding the underlying biology of PASC and directions toward future treatment.

Several themes have emerged in the biology, with inflammation and other immune alterations being the most common focus, potentially related to viral persistence, latent virus reactivation, and/or tissue damage and dysfunction, especially of the endothelium, nervous system, and mitochondria.

In order to develop safe and effective treatments for people with PASC, critical next steps should focus on the replication of major findings regarding potential mechanisms, disentangling pathogenic mechanisms from downstream effects, development of cellular and animal models, mechanism-focused randomized, placebo-controlled trials, and closer collaboration between people with lived experience, scientists, and other stakeholders.

Ultimately, by learning from other post-infectious syndromes, the knowledge gained may help not only those with PASC/Long COVID, but also those with other post-infectious syndromes.

Source: Matthew S. Durstenfeld, Shannon Weiman, Michael Holtzman, Catherine Blish, Resia Pretorius, Steven G. Deeks. Long COVID and post-acute sequelae of SARS-CoV-2 pathogenesis and treatment: A Keystone Symposia report. First published: 09 April 2024 https://doi.org/10.1111/nyas.15132 https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/nyas.15132 (Full text)

Cluster analysis of long COVID symptoms for deciphering a syndrome and its long-term consequence

Abstract:

The long-term symptoms of COVID-19 are the subject of public and scientific discussions. Understanding how those long COVID symptoms co-occur in clusters of syndromes may indicate the pathogenic mechanisms of long COVID. Our study objective was to cluster the different long COVID symptoms. We included persons who had a COVID-19 and assessed long-term symptoms (at least 4 weeks after first symptoms). Hierarchical clustering was applied to the symptoms as well as to the participants based on the Euclidean distance h of the log-values of the answers on symptom severity. The distribution of clusters within our cohort is shown in a heat map.

From September 2021 to November 2023, 2371 persons with persisting long COVID symptoms participated in the study. Self-assessed long COVID symptoms were assigned to three symptom clusters. Cluster A unites rheumatological and neurological symptoms, cluster B includes neuro-psychological symptoms together with cardiorespiratory symptoms, and a third cluster C shows an association of general infection signs, dermatological and otology symptoms. A high proportion of the participants (n = 1424) showed symptoms of all three clusters.

Clustering of long COVID symptoms reveals similarities to the symptomatology of already described syndromes such as the Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) or rheumatological autoinflammatory diseases. Further research may identify serological parameters or clinical risk factors associated with the shown clusters and might improve our understanding of long COVID as a systemic disease. Furthermore, multimodal treatments can be developed and scaled for symptom clusters and associated impairments.

Source: Niewolik J, Mikuteit M, Klawitter S, Schröder D, Stölting A, Vahldiek K, Heinemann S, Müller F, Behrens G, Klawonn F, Dopfer-Jablonka A, Steffens S. Cluster analysis of long COVID symptoms for deciphering a syndrome and its long-term consequence. Immunol Res. 2024 Apr 16. doi: 10.1007/s12026-024-09465-w. Epub ahead of print. PMID: 38627327. https://link.springer.com/article/10.1007/s12026-024-09465-w (Full text)

Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease

Abstract:

One in ten severe acute respiratory syndrome coronavirus 2 infections result in prolonged symptoms termed long coronavirus disease (COVID), yet disease phenotypes and mechanisms are poorly understood1. Here we profiled 368 plasma proteins in 657 participants ≥3 months following hospitalization. Of these, 426 had at least one long COVID symptom and 233 had fully recovered.

Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment. Additional markers of alterations in nerve tissue repair (SPON-1 and NFASC) were elevated in those with cognitive impairment and SCG3, suggestive of brain-gut axis disturbance, was elevated in gastrointestinal symptoms.

Severe acute respiratory syndrome coronavirus 2-specific immunoglobulin G (IgG) was persistently elevated in some individuals with long COVID, but virus was not detected in sputum. Analysis of inflammatory markers in nasal fluids showed no association with symptoms.

Our study aimed to understand inflammatory processes that underlie long COVID and was not designed for biomarker discovery. Our findings suggest that specific inflammatory pathways related to tissue damage are implicated in subtypes of long COVID, which might be targeted in future therapeutic trials.

Source: Liew F, Efstathiou C, Fontanella S, Richardson M, Saunders R, Swieboda D, Sidhu JK, Ascough S, Moore SC, Mohamed N, Nunag J, King C, Leavy OC, Elneima O, McAuley HJC, Shikotra A, Singapuri A, Sereno M, Harris VC, Houchen-Wolloff L, Greening NJ, Lone NI, Thorpe M, Thompson AAR, Rowland-Jones SL, Docherty AB, Chalmers JD, Ho LP, Horsley A, Raman B, Poinasamy K, Marks M, Kon OM, Howard LS, Wootton DG, Quint JK, de Silva TI, Ho A, Chiu C, Harrison EM, Greenhalf W, Baillie JK, Semple MG, Turtle L, Evans RA, Wain LV, Brightling C, Thwaites RS, Openshaw PJM; PHOSP-COVID collaborative group; ISARIC investigators. Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease. Nat Immunol. 2024 Apr;25(4):607-621. doi: 10.1038/s41590-024-01778-0. Epub 2024 Apr 8. PMID: 38589621; PMCID: PMC11003868. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11003868/ (Full text)