Tag: long covid biomarker

Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation

Abstract:

Background: Post-COVID-19 syndrome (PCS) is a lingering disease with ongoing symptoms such as fatigue and cognitive impairment resulting in a high impact on the daily life of patients. Understanding the pathophysiology of PCS is a public health priority, as it still poses a diagnostic and treatment challenge for physicians.

Methods: In this prospective observational cohort study, we analyzed the retinal microcirculation using Retinal Vessel Analysis (RVA) in a cohort of patients with PCS and compared it to an age- and gender-matched healthy cohort (n=41, matched out of n = 204).

Measurements and main results: PCS patients exhibit persistent endothelial dysfunction (ED), as indicated by significantly lower venular flicker-induced dilation (vmax; 3.42% ± 1.77% vs. 4.64 % ± 2.59%; p = 0.02), narrower central retinal artery equivalent (CRAE; 178.1 [167.5 – 190.2] vs. 189.1 [179.4 – 197.2], p = 0.01) and lower arteriolar-venular ratio (AVR; (0.84 [0.8 – 0.9] vs. 0.88 [0.8 – 0.9], p = 0.007). When combining AVR and vmax, predicted scores reached good ability to discriminate groups (area under the curve: 0.75). Higher PCS severity scores correlated with lower AVR (R= -0.37 p = 0.017). The association of microvascular changes with PCS severity were amplified in PCS patients exhibiting higher levels of inflammatory parameters.

Conclusion: Our results demonstrate that prolonged endothelial dysfunction is a hallmark of PCS, and impairments of the microcirculation seem to explain ongoing symptoms in patients. As potential therapies for PCS emerge, RVA parameters may become relevant as clinical biomarkers for diagnosis and therapy management.

Source: Timon Kuchler, Roman Günthner, Andrea Ribeiro et al. Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation, 22 May 2023, PREPRINT (Version 1) available at Research Square https://doi.org/10.21203/rs.3.rs-2952588/v1 (Full text)

Laboratory Findings and Biomarkers in Long COVID: What Do We Know So Far? Insights Into Epidemiology, Pathogenesis, Therapeutic Perspectives and Challenges

Abstract:

Long COVID (LC) encompasses a constellation of long-term symptoms experienced by at least 10% of people after the initial SARS-CoV-2 infection, and so far has affected about 65 million people. The etiology of LC remains unclear; however, many pathophysiological pathways may be involved, including viral persistence; chronic, low grade inflammatory response; immune dysregulation and defective immune response; reactivation of latent viruses; autoimmunity; persistent endothelial dysfunction and coagulopathy; gut dysbiosis; hormonal dysregulation, mitochondrial dysfunction; and autonomic nervous system dysfunction.

There are no specific tests for the diagnosis of LC, and clinical features including laboratory findings and biomarkers may not specifically relate to LC. Therefore, it is of paramount importance to develop and validate biomarkers that can be employed for the prediction, diagnosis and prognosis of LC and its therapeutic response. Promising candidate biomarkers that are found in some patients are markers of systemic inflammation including acute phase proteins, cytokines and chemokines; biomarkers reflecting SARS-CoV-2 persistence, reactivation of herpesviruses and immune dysregulation; biomarkers of endotheliopathy, coagulation and fibrinolysis; microbiota alterations; diverse proteins and metabolites; hormonal and metabolic biomarkers; as well as cerebrospinal fluid biomarkers. At present, there are only two reviews summarizing relevant biomarkers; however, they do not cover the entire umbrella of current biomarkers or their link to etiopathogenetic mechanisms, and the diagnostic work-up in a comprehensive manner.

Herein, we aim to appraise and synopsize the available evidence on the typical laboratory manifestations and candidate biomarkers of LC, their classification based on main LC symptomatology in the frame of the epidemiological and pathogenetic aspects of the syndrome, and furthermore assess limitations and challenges as well as potential implications in candidate therapeutic interventions.

Source: Tsilingiris, D.; Vallianou, N.G.; Karampela, I.; Christodoulatos, G.S.; Papavasileiou, G.; Petropoulou, D.; Magkos, F.; Dalamaga, M. Laboratory Findings and Biomarkers in Long COVID: What Do We Know So Far? Insights Into Epidemiology, Pathogenesis, Therapeutic Perspectives and Challenges. Preprints.org 2023, 2023051487. https://doi.org/10.20944/preprints202305.1487.v1 (Full text available as PDF file)

Long COVID: Plasma levels of neurofilament light chain in mild COVID-19 patients with neurocognitive symptoms

Abstract:

It is well known the potential of severe acute respiratory coronavirus type 2 (SARS-CoV-2) infection to induce post-acute sequelae, a condition called Long COVID. This syndrome includes several symptoms, but the central nervous system (CNS) main one is neurocognitive dysfunction. Recently it has been demonstrated the relevance of plasma levels of neurofilament light chain (pNfL), as a biomarker of early involvement of the CNS in COVID-19.

The aim of this study was to investigate the relationship between pNfL in patients with post-acute neurocognitive symptoms and the potential of NfL as a prognostic biomarker in these cases. A group of 63 long COVID patients ranging from 18 to 59 years-old were evaluated, submitted to a neurocognitive battery assessment, and subdivided in different groups, according to results. Plasma samples were collected during the long COVID assessment and used for measurement of pNfL with the Single molecule array (SIMOA) assays. Levels of pNfL were significantly higher in long COVID patients with neurocognitive symptoms when compared to HC (p = 0.0031).

Long COVID patients with cognitive impairment and fatigue symptoms presented higher pNfL levels when compared to long COVID patients without these symptoms, individually and combined (p = 0.0263, p = 0.0480, and 0.0142, respectively). Correlation analysis showed that levels of cognitive lost and exacerbation of fatigue in the neurocognitive evaluation had a significative correlation with higher pNfL levels (p = 0.0219 and 0.0255, respectively). Previous reports suggested that pNfL levels are related with higher risk of severity and predict lethality of COVID-19.

Our findings demonstrate that SARS-CoV-2 infection seems to have a long-term impact on the brain, even in patients who presented mild acute disease. NfL measurements might be useful to identify CNS involvement in long COVID associated with neurocognitive symptoms and to identify who will need continuous monitoring and treatment support.

Source: Gutman E, Salvio A, Fernandes R, et al. Long COVID: Plasma levels of neurofilament light chain in mild COVID-19 patients with neurocognitive symptoms. Research Square; 2023. DOI: 10.21203/rs.3.rs-2921879/v1. https://www.researchsquare.com/article/rs-2921879/v1 (Full text)

Reduced exercise capacity, chronotropic incompetence, and early systemic inflammation in cardiopulmonary phenotype Long COVID

Abstract:

Background: Mechanisms underlying persistent cardiopulmonary symptoms following SARS-CoV-2 infection (post-acute sequelae of COVID-19 “PASC” or “Long COVID”) remain unclear. This study sought to elucidate mechanisms of cardiopulmonary symptoms and reduced exercise capacity.

Methods: We conducted cardiopulmonary exercise testing (CPET), cardiac magnetic resonance imaging (CMR) and ambulatory rhythm monitoring among adults > 1 year after confirmed SARS-CoV-2 infection in a post-COVID cohort, compared those with or without symptoms, and correlated findings with previously measured biomarkers.

Results: Sixty participants (median age 53, 42% female, 87% non-hospitalized) were studied at median 17.6 months following SARS-CoV-2 infection. On CPET, 18/37 (49%) with symptoms had reduced exercise capacity (<85% predicted) compared to 3/19 (16%) without symptoms (p = 0.02). Adjusted peak VO2 was 5.2 ml/kg/min lower (95%CI 2.1-8.3; p = 0.001) or 16.9% lower percent predicted (95%CI 4.3-29.6; p = 0.02) among those with symptoms. Chronotropic incompetence was common. Inflammatory markers and antibody levels early in PASC were negatively correlated with peak VO2 more than 1 year later. Late-gadolinium enhancement on CMR and arrhythmias were absent.

Conclusions: Cardiopulmonary symptoms >1 year following COVID-19 were associated with reduced exercise capacity, which was associated with elevated inflammatory markers early in PASC. Chronotropic incompetence may explain exercise intolerance among some with cardiopulmonary Long COVID.

Source: Durstenfeld MS, Peluso MJ, Kaveti P, Hill C, Li D, Sander E, Swaminathan S, Arechiga VM, Lu S, Goldberg SA, Hoh R, Chenna A, Yee BC, Winslow JW, Petropoulos CJ, Kelly JD, Glidden DV, Henrich TJ, Martin JN, Lee YJ, Aras MA, Long CS, Grandis DJ, Deeks SG, Hsue PY. Reduced exercise capacity, chronotropic incompetence, and early systemic inflammation in cardiopulmonary phenotype Long COVID. J Infect Dis. 2023 May 11:jiad131. doi: 10.1093/infdis/jiad131. Epub ahead of print. PMID: 37166076. https://academic.oup.com/jid/advance-article/doi/10.1093/infdis/jiad131/7159960 (Full text available as PDF file)

The fatal trajectory of pulmonary COVID-19 is driven by lobular ischemia and fibrotic remodelling

Abstract:

Background: COVID-19 is characterized by a heterogeneous clinical presentation, ranging from mild symptoms to severe courses of disease. 9-20% of hospitalized patients with severe lung disease die from COVID-19 and a substantial number of survivors develop long-COVID. Our objective was to provide comprehensive insights into the pathophysiology of severe COVID-19 and to identify liquid biomarkers for disease severity and therapy response.

Methods: We studied a total of 85 lungs (n = 31 COVID autopsy samples; n = 7 influenza A autopsy samples; n = 18 interstitial lung disease explants; n = 24 healthy controls) using the highest resolution Synchrotron radiation-based hierarchical phase-contrast tomography, scanning electron microscopy of microvascular corrosion casts, immunohistochemistry, matrix-assisted laser desorption ionization mass spectrometry imaging, and analysis of mRNA expression and biological pathways. Plasma samples from all disease groups were used for liquid biomarker determination using ELISA. The anatomic/molecular data were analyzed as a function of patients’ hospitalization time.

Findings: The observed patchy/mosaic appearance of COVID-19 in conventional lung imaging resulted from microvascular occlusion and secondary lobular ischemia. The length of hospitalization was associated with increased intussusceptive angiogenesis. This was associated with enhanced angiogenic, and fibrotic gene expression demonstrated by molecular profiling and metabolomic analysis. Increased plasma fibrosis markers correlated with their pulmonary tissue transcript levels and predicted disease severity. Plasma analysis confirmed distinct fibrosis biomarkers (TSP2, GDF15, IGFBP7, Pro-C3) that predicted the fatal trajectory in COVID-19.

Interpretation: Pulmonary severe COVID-19 is a consequence of secondary lobular microischemia and fibrotic remodelling, resulting in a distinctive form of fibrotic interstitial lung disease that contributes to long-COVID.

Source: Ackermann M, Kamp JC, Werlein C, Walsh CL, Stark H, Prade V, Surabattula R, Wagner WL, Disney C, Bodey AJ, Illig T, Leeming DJ, Karsdal MA, Tzankov A, Boor P, Kühnel MP, Länger FP, Verleden SE, Kvasnicka HM, Kreipe HH, Haverich A, Black SM, Walch A, Tafforeau P, Lee PD, Hoeper MM, Welte T, Seeliger B, David S, Schuppan D, Mentzer SJ, Jonigk DD. The fatal trajectory of pulmonary COVID-19 is driven by lobular ischemia and fibrotic remodelling. EBioMedicine. 2022 Nov;85:104296. doi: 10.1016/j.ebiom.2022.104296. Epub 2022 Oct 4. PMID: 36206625; PMCID: PMC9535314. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9535314/ (Full text)

Increased interleukin-6 is associated with long COVID-19: a systematic review and meta-analysis

Abstract:

Background: Coronavirus disease 2019 (COVID-19) can involve persistence, sequelae, and other clinical complications that last weeks to months to evolve into long COVID-19. Exploratory studies have suggested that interleukin-6 (IL-6) is related to COVID-19; however, the correlation between IL-6 and long COVID-19 is unknown. We designed a systematic review and meta-analysis to assess the relationship between IL-6 levels and long COVID-19.

Methods: Databases were systematically searched for articles with data on long COVID-19 and IL-6 levels published before September 2022. A total of 22 published studies were eligible for inclusion following the PRISMA guidelines. Analysis of data was undertaken by using Cochran’s Q test and the Higgins I-squared (I2) statistic for heterogeneity. Random-effect meta-analyses were conducted to pool the IL-6 levels of long COVID-19 patients and to compare the differences in IL-6 levels among the long COVID-19, healthy, non-postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (non-PASC), and acute COVID-19 populations. The funnel plot and Egger’s test were used to assess potential publication bias. Sensitivity analysis was used to test the stability of the results.

Results: An increase in IL-6 levels was observed after SARS-CoV-2 infection. The pooled estimate of IL-6 revealed a mean value of 20.92 pg/ml (95% CI = 9.30-32.54 pg/ml, I2 = 100%, P < 0.01) for long COVID-19 patients. The forest plot showed high levels of IL-6 for long COVID-19 compared with healthy controls (mean difference = 9.75 pg/ml, 95% CI = 5.75-13.75 pg/ml, I2 = 100%, P < 0.00001) and PASC category (mean difference = 3.32 pg/ml, 95% CI = 0.22-6.42 pg/ml, I2 = 88%, P = 0.04). The symmetry of the funnel plots was not obvious, and Egger’s test showed that there was no significant small study effect in all groups.

Conclusions: This study showed that increased IL-6 correlates with long COVID-19. Such an informative revelation suggests IL-6 as a basic determinant to predict long COVID-19 or at least inform on the “early stage” of long COVID-19.

Source: Yin JX, Agbana YL, Sun ZS, Fei SW, Zhao HQ, Zhou XN, Chen JH, Kassegne K. Increased interleukin-6 is associated with long COVID-19: a systematic review and meta-analysis. Infect Dis Poverty. 2023 Apr 24;12(1):43. doi: 10.1186/s40249-023-01086-z. PMID: 37095536; PMCID: PMC10123579. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10123579/ (Full text)

Clinical improvement of Long-COVID is associated with reduction in autoantibodies, lipids, and inflammation following therapeutic apheresis

Abstract:

In the aftermath of the COVID-19 pandemic, we are witnessing an unprecedented wave of post-infectious complications. Most prominently, millions of patients with Long-Covid complain about chronic fatigue and severe post-exertional malaise. Therapeutic apheresis has been suggested as an efficient treatment option for alleviating and mitigating symptoms in this desperate group of patients. However, little is known about the mechanisms and biomarkers correlating with treatment outcomes.

Here, we have analyzed in different cohorts of Long-Covid patients specific biomarkers before and after therapeutic apheresis. In patients that reported a significant improvement following two cycles of therapeutic apheresis, there was a significant reduction in neurotransmitter autoantibodies, lipids, and inflammatory markers. Furthermore, we observed a 70% reduction in fibrinogen, and following apheresis, erythrocyte rouleaux formation and fibrin fibers largely disappeared as demonstrated by dark field microscopy.

This is the first study demonstrating a pattern of specific biomarkers with clinical symptoms in this patient group. It may therefore form the basis for a more objective monitoring and a clinical score for the treatment of Long-Covid and other postinfectious syndromes.

Source: Achleitner, M., Steenblock, C., Dänhardt, J. et al. Clinical improvement of Long-COVID is associated with reduction in autoantibodies, lipids, and inflammation following therapeutic apheresis. Mol Psychiatry (2023). https://doi.org/10.1038/s41380-023-02084-1 https://www.nature.com/articles/s41380-023-02084-1 (Full text)

Unique immune and inflammatory cytokine profiles may define long COVID syndrome

Abstract:

Purpose: Long COVID is estimated to occur in 5-10% of individuals after acute SARS-CoV-2 infection. However, the pathophysiology driving the disease process is poorly understood.

Methods: We evaluated urine and plasma inflammatory and immune cytokine profiles in 33 individuals with long COVID compared to 33 who were asymptomatic and recovered, and 34 without prior infection.

Results: Mean urinary leukotriene E4 was significantly elevated among individuals with long COVID compared to asymptomatic and recovered individuals (mean difference 774.2 pg/mL; SD 335.7) and individuals without prior SARS-CoV-2 infection (mean difference 503.1 pg/ml; SD 467.7). Plasma chemokine ligand 6 levels were elevated among individuals with long COVID compared to individuals with no prior SARS-CoV-2 infection (mean difference 0.59 units; SD 0.42). We found no significant difference in angiotensin-converting enzyme 2 antibody levels. Plasma tumor necrosis factor receptor-associated factor 2 (TRAF2) levels were reduced among individuals with long COVID compared to individuals who were asymptomatic and recovered (mean difference = 0.6 units, SD 0.46). Similarly, the mean level of Sarcoma Homology 2-B adapter protein 3 was 3.3 units (SD 1.24) among individuals with long COVID, lower than 4.2 units (SD 1.1) among individuals with recovered, asymptomatic COVID.

Conclusion: Our findings suggest that further studies should be conducted to evaluate the role of leukotriene E4 as a potential biomarker for a diagnostic test. Furthermore, based on reductions in TRAF2, long COVID may be driven in part by impaired TRAF2-dependent immune-mediated inflammation and potentially immune exhaustion.

Source: Allan-Blitz LT, Akbari O, Kojima N, Saavedra E, Chellamuthu P, Denny N, MacMullan MA, Hess V, Shacreaw M, Brobeck M, Turner F, Slepnev VI, Ibrayeva A, Klausner JD. Unique immune and inflammatory cytokine profiles may define long COVID syndrome. Clin Exp Med. 2023 Apr 16:1–6. doi: 10.1007/s10238-023-01065-6. Epub ahead of print. PMID: 37061998; PMCID: PMC10105906. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10105906/ (Full text)

Symptom persistence and biomarkers in post-COVID-19/chronic fatigue syndrome – results from a prospective observational cohort

Abstract:

Introduction: Post-COVID-19 syndrome (PCS) is characterized by a wide range of symptoms, predominantly fatigue and exertional intolerance. While disease courses during the first year post infection have been repeatedly described, little is known about long-term health consequences.

Methods: We assessed symptom severity and various biomarkers at three time points post infection (3-8 months (mo), 9-16mo, 17-20mo) in 106 PCS patients with moderate to severe fatigue and exertional intolerance. A subset of patients fulfilled diagnostic criteria of myalgic encephalomyelitis/chronic fatigue syndrome (PCS-ME/CFS) based on the Canadian Consensus Criteria.

Results: While PCS-ME/CFS patients showed persisting symptom severity and disability up to 20mo post infection, PCS patients reported an overall health improvement. Inflammatory biomarkers equally decreased in both groups. Lower hand grip force at onset correlated with symptom persistence especially in PCS-ME/CFS.

Discussion: Debilitating PCS may persist beyond 20mo post infection, particularly in patients fulfilling diagnostic criteria for ME/CFS.

Source: Anna Franziska Legler, Lil Meyer-Arndt, Lukas Moedl, Claudia Kedor, Helma Freitag, Elena Steinle, Uta Hoppmann, Rebekka Rust, Frank Konietschke, Andreas Thiel, Friedemann Paul, Carmen Scheibenbogen, Judith Bellmann-Strobl. Symptom persistence and biomarkers in post-COVID-19/chronic fatigue syndrome – results from a prospective observational cohort.
medRxiv 2023.04.15.23288582; doi: https://doi.org/10.1101/2023.04.15.23288582 (Full text available as PDF file)

Cellular and molecular biomarkers of long COVID: a scoping review

Abstract:

Background: Long-COVID (LC) encompasses diverse symptoms lasting months after the initial SARS-CoV-2 infection. Symptoms can be debilitating and affect the quality of life of individuals with LC and their families. Although the symptoms of LC are well described, the aetiology of LC remains unclear, and consequently, patients may be underdiagnosed. Identification of LC specific biomarkers is therefore paramount for the diagnosis and clinical management of the syndrome. This scoping review describes the molecular and cellular biomarkers that have been identified to date with potential use for diagnosis or prediction of LC.

Methods: This review was conducted using the Joanna Briggs Institute (JBI) Methodology for Scoping Reviews. A search was executed in the MEDLINE and EMBASE databases, as well as in the grey literature for original studies, published until October 5th, 2022, reporting biomarkers identified in participants with LC symptoms (from all ages, ethnicities, and sex), with a previous infection of SARS-CoV-2. Non-English studies, cross-sectional studies, studies without a control group, and pre-prints were excluded. Two reviewers independently evaluated the studies, extracted population data and associated biomarkers.

Findings: 23 cohort studies were identified, involving 2163 LC patients [median age 51.8 years, predominantly female sex (61.10%), white (75%), and non-vaccinated (99%)]. A total of 239 candidate biomarkers were identified, consisting mainly of immune cells, immunoglobulins, cytokines, and other plasma proteins. 19 of the 239 candidate biomarkers identified were evaluated by the authors, by means of receiver operating characteristic (ROC) curves.

Interpretation: Diverse cellular and molecular biomarkers for LC have been proposed. Validation of candidate biomarkers in independent samples should be prioritized. Modest reported performance (particularly in larger studies) suggests LC may encompass many distinct aetiologies, which should be explored e.g., by stratifying by symptom clusters and/or sex.

Source: Espín E, Yang C, Shannon CP, Assadian S, He D, Tebbutt SJ. Cellular and molecular biomarkers of long COVID: a scoping review. EBioMedicine. 2023 Apr 8;91:104552. doi: 10.1016/j.ebiom.2023.104552. Epub ahead of print. PMID: 37037165; PMCID: PMC10082390. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10082390/ (Full text)