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)

Mouse Adapted SARS-CoV-2 Model Induces “Long-COVID” Neuropathology in BALB/c Mice

Abstract:

The novel coronavirus SARS-CoV-2 has caused significant global morbidity and mortality and continues to burden patients with persisting neurological dysfunction. COVID-19 survivors develop debilitating symptoms to include neuro-psychological dysfunction, termed “Long COVID”, which can cause significant reduction of quality of life. Despite vigorous model development, the possible cause of these symptoms and the underlying pathophysiology of this devastating disease remains elusive.

Mouse adapted (MA10) SARS-CoV-2 is a novel mouse-based model of COVID-19 which simulates the clinical symptoms of respiratory distress associated with SARS-CoV-2 infection in mice. In this study, we evaluated the long-term effects of MA10 infection on brain pathology and neuroinflammation. 10-week and 1-year old female BALB/cAnNHsd mice were infected intranasally with 10 4 plaque-forming units (PFU) and 10 3 PFU of SARS-CoV-2 MA10, respectively, and the brain was examined 60 days post-infection (dpi).

Immunohistochemical analysis showed a decrease in the neuronal nuclear protein NeuN and an increase in Iba-1 positive amoeboid microglia in the hippocampus after MA10 infection, indicating long-term neurological changes in a brain area which is critical for long-term memory consolidation and processing. Importantly, these changes were seen in 40-50% of infected mice, which correlates to prevalence of LC seen clinically.

Our data shows for the first time that MA10 infection induces neuropathological outcomes several weeks after infection at similar rates of observed clinical prevalence of “Long COVID”. These observations strengthen the MA10 model as a viable model for study of the long-term effects of SARS-CoV-2 in humans. Establishing the viability of this model is a key step towards the rapid development of novel therapeutic strategies to ameliorate neuroinflammation and restore brain function in those suffering from the persistent cognitive dysfunction of “Long-COVID”.

Source: Gressett TE, Leist SR, Ismael S, Talkington G, Dinnon KH, Baric RS, Bix G. Mouse Adapted SARS-CoV-2 Model Induces “Long-COVID” Neuropathology in BALB/c Mice. bioRxiv [Preprint]. 2023 Mar 20:2023.03.18.533204. doi: 10.1101/2023.03.18.533204. PMID: 36993423; PMCID: PMC10055301. https://www.biorxiv.org/content/10.1101/2023.03.18.533204v1.full (Full text)

Risk factors for psychiatric symptoms in patients with long COVID: A systematic review

Abstract:

Prolonged symptoms of COVID-19 have been found in many patients, often known as Long COVID. Psychiatric symptoms are commonly seen in Long COVID patients and could last for weeks, even months, after recovery. However, the symptoms and risk factors associated with it remain unclear.

In the current systematic review, we provide an overview of psychiatric symptoms in Long COVID patients and risk factors associated with the development of those symptoms. Articles were systematically searched on SCOPUS, PubMed, and EMBASE up to October 2021. Studies involving adults and geriatric participants with a confirmed previous COVID-19 diagnosis and reported psychiatric symptoms that persist for more than four weeks after the initial infection were included. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) for observational studies. Prevalence rates and risk factors associated with psychiatric symptoms were collected. This present study was registered at PROSPERO (CRD42021240776). In total, 23 studies were included.

Several limitations in this review were the heterogeneity of studies’ outcomes and designs, studies limited to articles published in English, and the psychiatric symptoms mainly were assessed using self-report questionnaires. The most prevalent  reported psychiatric symptoms, from the most to the least reported, were anxiety, depression, post-traumatic stress disorder (PTSD), poor sleep qualities, somatic symptoms, and cognitive deficits. Being female and having previous psychiatric diagnoses were risk factors for the development of the reported symptoms.

Source: Zakia H, Pradana K, Iskandar S. Risk factors for psychiatric symptoms in patients with long COVID: A systematic review. PLoS One. 2023 Apr 7;18(4):e0284075. doi: 10.1371/journal.pone.0284075. PMID: 37027455; PMCID: PMC10081737. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10081737/ (Full text)

Five cluster classifications of long COVID and their background factors: A cross-sectional study in Japan

Abstract:

Purpose: The long-term symptoms of coronavirus disease 2019 (COVID-19), i.e., long COVID, have drawn research attention. Evaluating its subjective symptoms is difficult, and no established pathophysiology or treatment exists. Although there are several reports of long COVID classifications, there are no reports comparing classifications that include patient characteristics, such as autonomic dysfunction and work status. We aimed to classify patients into clusters based on their subjective symptoms during their first outpatient visit and evaluate their background for these clusters.

Methods: Included patients visited our outpatient clinic between January 18, 2021, and May 30, 2022. They were aged ≥ 15 years and confirmed to have SARS-CoV-2 infection and residual symptoms lasting at least 2 months post-infection. Patients were evaluated using a 3-point scale for 23 symptoms and classified into five clusters (1. fatigue only; 2. fatigue, dyspnea, chest pain, palpitations, and forgetfulness; 3. fatigue, headache, insomnia, anxiety, motivation loss, low mood, and forgetfulness; 4. hair loss; and 5. taste and smell disorders) using CLUSTER. For continuous variables, each cluster was compared using the Kruskal–Wallis test. Multiple comparison tests were performed using the Dunn’s test for significant results. For nominal variables, a Chi-square test was performed; for significant results, a residual analysis was conducted with the adjusted residuals.

Results: Compared to patients in other cluster categories, those in cluster categories 2 and 3 had higher proportions of autonomic nervous system disorders and leaves of absence, respectively.

Conclusions: Long COVID cluster classification provided an overall assessment of COVID-19. Different treatment strategies must be used based on physical and psychiatric symptoms and employment factors.

Source: Tsuchida, T., Yoshimura, N., Ishizuka, K. et al. Five cluster classifications of long COVID and their background factors: A cross-sectional study in Japan. Clin Exp Med (2023). https://doi.org/10.1007/s10238-023-01057-6 (Full text)

Exercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-Acute Sequelae of SARS-CoV-2: More in Common Than Not?

Abstract:

Topic importance: Post-Acute Sequelae of SARS-CoV-2 (PASC) is a long-term consequence of acute infection from coronavirus disease 2019 (COVID-19). Clinical overlap between PASC and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has been observed, with shared symptoms including intractable fatigue, postexertional malaise, and orthostatic intolerance. The mechanistic underpinnings of such symptoms are poorly understood.

Review findings: Early studies suggest deconditioning as the primary explanation for exertional intolerance in PASC. Cardiopulmonary exercise testing (CPET) reveals perturbations related to systemic blood flow and ventilatory control associated with acute exercise intolerance in PASC, which are not typical of simple detraining. Hemodynamic and gas exchange derangements in PASC have substantial overlap with those observed with ME/CFS, suggestive of shared mechanisms.

Summary: This review aims to illustrate exercise pathophysiologic commonalities between PASC and ME/CFS that will help guide future diagnostics and treatment.

Source: Joseph P, Singh I, Oliveira R, Capone CA, Mullen MP, Cook DB, Stovall MC, Squires J, Madsen K, Waxman AB, Systrom DM. Exercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-Acute Sequelae of SARS-CoV-2: More in Common Than Not? Chest. 2023 Apr 11:S0012-3692(23)00502-0. doi: 10.1016/j.chest.2023.03.049. Epub ahead of print. PMID: 37054777; PMCID: PMC10088277. https://pubmed.ncbi.nlm.nih.gov/37054777/

Data-driven analysis to understand long COVID using electronic health records from the RECOVER initiative

Abstract:

Recent studies have investigated post-acute sequelae of SARS-CoV-2 infection (PASC, or long COVID) using real-world patient data such as electronic health records (EHR). Prior studies have typically been conducted on patient cohorts with specific patient populations which makes their generalizability unclear. This study aims to characterize PASC using the EHR data warehouses from two large Patient-Centered Clinical Research Networks (PCORnet), INSIGHT and OneFlorida+, which include 11 million patients in New York City (NYC) area and 16.8 million patients in Florida respectively.

With a high-throughput screening pipeline based on propensity score and inverse probability of treatment weighting, we identified a broad list of diagnoses and medications which exhibited significantly higher incidence risk for patients 30-180 days after the laboratory-confirmed SARS-CoV-2 infection compared to non-infected patients.

We identified more PASC diagnoses in NYC than in Florida regarding our screening criteria, and conditions including dementia, hair loss, pressure ulcers, pulmonary fibrosis, dyspnea, pulmonary embolism, chest pain, abnormal heartbeat, malaise, and fatigue, were replicated across both cohorts. Our analyses highlight potentially heterogeneous risks of PASC in different populations.

Source: Zang C, Zhang Y, Xu J, Bian J, Morozyuk D, Schenck EJ, Khullar D, Nordvig AS, Shenkman EA, Rothman RL, Block JP, Lyman K, Weiner MG, Carton TW, Wang F, Kaushal R. Data-driven analysis to understand long COVID using electronic health records from the RECOVER initiative. Nat Commun. 2023 Apr 7;14(1):1948. doi: 10.1038/s41467-023-37653-z. PMID: 37029117; PMCID: PMC10080528. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10080528/ (Full text)

Prevalence and Characterization of Long Covid-19 Symptoms in Health Care Professionals- A Need of the Hour

Abstract:

Background: With the global advent of Covid-19, Healthcare workers (HCW) were under a lot of physical and psychological pressure. Information on persistent symptoms post Covid-19 Infection in HCWs is lacking.

Objectives: This Study is aimed at assessing the impact of the post Covid-19 syndrome in HCWs.

Materials and Methods: A Questionnaire was prepared as google form and shared with the HCWs through WhatsApp enquiring regarding the health conditions that are still persistent post recovery from Covid-19 infection.

Results: A total of 328 Health Care Professionals participated in the present survey (18-65 yrs). The gender distribution revealed 67.7% were females and 32.3% were males. 60.3% of the participants were infected with COVID-19 before taking the first dose of vaccination which is reduced to 17.5% after vaccination. The post COVID complications observed from the study were hair loss (35.4%), easy fatigability (25%), mood swings (22.9%), anxiety (18.8%), insomnia/sleeplessness (13.9%), depression (12.5%) and joint pains/arthritis (11.8%). The other complications observed were loss of taste (9%), lightheadedness/postural hypotension (8.3%), amnesia/loss of memory and anosmia/loss of smell (7.6%), gastritis (6.3%), palpitations, hypersomnia and pulmonary complications (5.6%) and chest pain (4.9%). Unpaired t-test and One-Way ANNOVA resulted in a significant value (p values of >0.05).

Discussion: Despite the fact that females experienced more post-Covid-19 symptoms (15 out of 17), males experienced more chest pain and anxiety symptoms. According to our findings, 57 of 100 Covid-19 health care workers have post-Covid complications. The participants presented with non-specific symptoms such as easy fatigability, mood swings, light headedness, anxiety but most of the participants quoted more specific symptoms such as depression, pulmonary complications, hair loss, joint pains, gastritis, chest pain, palpitations, loss of taste, amnesia, hyperglycemia, insomnia, hypersomnia and anosmia. However, non-specific symptoms such as fatigue, mood swings, lightheadedness, and anxiety were also mentioned. The symptoms of post-acute COVID-19 syndrome vary greatly. Early detection requires a unified definition of long COVID and characterization of its manifestation. Furthermore, more research should be conducted to identify risk factors and the precise mechanisms that lead to the development of long COVID syndrome. Such knowledge may aid future research aimed at preventing such a complication.

Source: Mote Srinath, Syeda Fakiha Mehreen, Surya Prem Kumar et al. Prevalence and Characterization of Long Covid-19 Symptoms in Health Care Professionals- A Need of the Hour, 05 April 2023, PREPRINT (Version 1) available at Research Square. https://doi.org/10.21203/rs.3.rs-2764197/v1 (Full text)

High levels of pro-inflammatory SARS-CoV-2-specific biomarkers revealed by in vitro whole blood cytokine release assay (CRA) in recovered and long-COVID-19 patients

Abstract:

Background: Cytokines induced by SARS-CoV-2 infection play a crucial role in the pathophysiology of COVID-19 and hyperinflammatory responses have been associated with poor clinical outcomes, with progression to severe conditions or long-term subacute complications named as long-COVID-19.

Methods: In this cross-sectional study, we aimed to evaluate a set of antigen-specific inflammatory cytokines in blood from recovered COVID-19 individuals or who suffered a post-acute phase of SARS-CoV-2 infection compared to healthy individuals with no history of COVID-19 exposition or infection. Interferon-gamma (IFN-γ), IFN-γ-induced protein 10 (IP-10), tumor necrosis factor (TNF), IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, and IL-17A were quantified by multiplex cytometric bead assay and enzyme-linked immunosorbent assay after stimulation of whole blood with recombinant Spike protein from SARS-CoV-2. Additionally, all participants have evaluated for anti-(S) protein-specific IgG antibodies. Clinical specimens were collected within two months of COVID-19 diagnosis.

Results: A total of 47 individuals were enrolled in the study, a median age of 43 years (IQR = 14.5), grouped into healthy individuals with no history of infection or exposure to SARS-CoV-2 (unexposed group; N = 21); and patients from the Health Complex of the Rio de Janeiro State University (UERJ), Brazil, who were SARS-CoV-2 positive by RT-PCR (COVID-19 group)–categorized as recovered COVID-19 (N = 11) or long-COVID-19 (N = 15). All COVID-19 patients presented at least one signal or symptom during the first two weeks of infection. Six patients were hospitalized and required invasive mechanical ventilation.

Our results showed that COVID-19 patients had significantly higher levels of IFN-γ, TNF, IL-1β, IL-2, IL-6, IL-8, and IP-10 than the unexposed group. The long-COVID-19 group has presented significantly high levels of IL-1β and IL-6 compared to unexposed individuals, but not from recovered COVID-19. A principal-component analysis demonstrated 84.3% of the total variance of inflammatory-SARS-CoV-2 response in the first two components, and it was possible to stratify IL-6, TNF, IL-1β, IL-10, and IL-2 as the top-five cytokines which are candidates to discriminate COVID-19 group (including long-COVID-19 subgroup) and healthy unexposed individuals.

Conclusion: We revealed important S protein-specific differential biomarkers in individuals affected by COVID-19, bringing new insights into the inflammatory status or SARS-CoV-2 exposition determination.

Source: Gomes SMR, Brito ACdS, Manfro WFP, Ribeiro-Alves M, Ribeiro RSdA, da Cal MS, et al. (2023) High levels of pro-inflammatory SARS-CoV-2-specific biomarkers revealed by in vitro whole blood cytokine release assay (CRA) in recovered and long-COVID-19 patients. PLoS ONE 18(4): e0283983. https://doi.org/10.1371/journal.pone.0283983 (Full text)

Gut Microbiota Dysbiosis Correlates With Long COVID-19 at One-Year After Discharge

Abstract:

Background: Long coronavirus disease 2019 (COVID-19) in recovered patients (RPs) is gradually recognized by more people. However, how long it will last and the underlining mechanism remains unclear.
Methods: We conducted a prospective follow-up study to evaluate the long-term symptoms and clinical indices of RPs at one-year after discharge from Union Hospital, Wuhan, China between December 2020 to May 2021. We also performed the 16S rRNA sequencing of stool samples from RPs and healthy controls (HCs) and analyzed the correlation between the gut microbiota and long COVID-19.
Results: In total, 187 RPs were enrolled, among them, 84 (44.9%) RPs reported long COVID-19 symptoms at one-year after discharge. The most common long-term symptoms were cardiopulmonary symptoms, including chest tightness after activity (39/187, 20.9%), palpitations on exercise (27/187, 14.4%), sputum (21/187, 11.2%), cough (15/187, 8.0%) and chest pain (13/187, 7.0%), followed by systemic symptoms including fatigue (34/187, 18.2%) and myalgia (20/187, 10.7%), and digestive symptoms including constipation (14/187, 7.5%), anorexia (13/187, 7.0%), and diarrhea (8/187, 4.3%). Sixty-six (35.9%) RPs presented either anxiety or depression (42/187 [22.8%] and 53/187 [28.8%] respectively), and the proportion of anxiety or depression in the long symptomatic group was significantly higher than that in the asymptomatic group (41/187 [50.6%] vs. 25/187 [24.3%]). Compared with the asymptomatic group, scores of all nine 36-Item Short Form General Health Survey domains were lower in the symptomatic group (all P < 0.05).
One hundred thirty RPs and 32 HCs (non-severe acute respiratory syndrome coronavirus 2 infected subjects) performed fecal sample sequencing. Compared with HCs, symptomatic RPs had obvious gut microbiota dysbiosis including significantly reduced bacterial diversities and lower relative abundance of short-chain fatty acids (SCFAs)-producing salutary symbionts such as Eubacterium_hallii_group,  SubdoligranulumRuminococcusDorea, Coprococcus, and Eubacterium_ventriosum_group. Meanwhile, the relative abundance of Eubacterium_hallii_group,  Subdoligranulum, and Ruminococcus showed decreasing tendencies between HCs, the asymptomatic group, and the symptomatic group.
Conclusion: This study demonstrated the presence of long COVID-19 which correlates with gut microbiota dysbiosis in RPs at one-year after discharge, indicating gut microbiota may play an important role in long COVID-19.
Source: Zhang D, Zhou Y, Ma Y, Chen P, Tang J, Yang B, Li H, Liang M, Xue Y, Liu Y, Zhang J, Wang X. Gut Microbiota Dysbiosis Correlates With Long COVID-19 at One-Year After Discharge. J Korean Med Sci. 2023;38(15):e120. https://doi.org/10.3346/jkms.2023.38.e120 (Full text)

Fatigue, sleepiness and sleep quality are SARS-CoV-2 variant independent in patients with long COVID symptoms

Abstract:

Acute infections with SARS-CoV-2 variants of concerns (VOCs) differ in clinical presentation. Discrepancies in their long-term sequelae, commonly referred to as long COVID, however, remain to be explored. We retrospectively analyzed data of 287 patients presented at the post-COVID care of the Pulmonology Department, Semmelweis University, Budapest, Hungary, and infected with SARS-CoV-2 during a period of 3 major epidemic waves in Hungary (February-July 2021, VOC: B.1.1.7, Alpha, N = 135; August-December 2021, VOC: B.1.617.2, Delta, N = 89; and January-June 2022, VOC: B.1.1.529, Omicron; N = 63), > 4 weeks after acute COVID-19.

Overall, the ratio of long COVID symptomatic (LC) and asymptomatic (NS) patients was 2:1. Self-reported questionnaires on fatigue (Fatigue Severity Scale, FSS), sleepiness (Epworth Sleepiness Scale, ESS) and sleep quality (Pittsburgh Sleep Quality Index, PSQI) showed higher scores for LC (4.79 ± 0.12, 7.45 ± 0.33 and 7.46 ± 0.27, respectively) than NS patients (2.85 ± 0.16, 5.23 ± 0.32 and 4.26 ± 0.29, respectively; p < 0.05 for all vs. LC). By comparing data of the three waves, mean FSS and PSQI scores of LC patients, but not ESS scores, exceeded the normal range in all, with no significant inter-wave differences.

Considering FSS ≥ 4 and PSQI > 5 cutoff values, LC patients commonly exhibited problematic fatigue (≥ 70%) and poor sleep quality (> 60%) in all three waves. Comparative analysis of PSQI component scores of LC patients identified no significant differences between the three waves.

Our findings highlight the importance of concerted efforts to manage both fatigue and sleep disturbances in long COVID patient care. This multifaceted approach should be followed in all cases infected with either VOCs of SARS-CoV-2.

Source: Percze AR, Nagy A, Polivka L, Barczi E, Czaller I, Kovats Z, Varga JT, Ballai JH, Muller V, Horvath G. Fatigue, sleepiness and sleep quality are SARS-CoV-2 variant independent in patients with long COVID symptoms. Inflammopharmacology. 2023 Apr 5:1–7. doi: 10.1007/s10787-023-01190-4. Epub ahead of print. PMID: 37020055; PMCID: PMC10075170. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10075170/ (Full text)