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

Immune activation and immune-associated neurotoxicity in Long-COVID: A systematic review and meta-analysis of 103 studies comprising 58 cytokines/chemokines/growth factors

BACKGROUND

Multiple studies have shown that Long COVID (LC) disease is associated with heightened immune activation, as evidenced by elevated levels of inflammatory mediators. However, there is no comprehensive meta-analysis focusing on activation of the immune inflammatory response system (IRS) and the compensatory immunoregulatory system (CIRS) along with other immune phenotypes in LC patients.

OBJECTIVES

This meta-analysis is designed to explore the IRS and CIRS profiles in LC patients, the individual cytokines, chemokines, growth factors, along with C-reactive protein (CRP) and immune-associated neurotoxicity.

METHODS

To gather relevant studies for our research, we conducted a thorough search using databases such as PubMed, Google Scholar, and SciFinder, covering all available literature up to July 5th, 2024.

RESULTS

The current meta-analysis encompassed 103 studies that examined multiple immune profiles, C-reactive protein, and 58 cytokines/chemokines/growth factors in 5502 LC patients versus 5962 normal controls (NC). LC patients showed significant increases in IRS/CIRS ratio (standardized mean difference (SMD: 0.156, confidence interval (CI): 0.062;0.250), IRS (SMD: 0.338, CI: 0.236;0.440), M1 macrophage (SMD: 0.371, CI: 0.263;0.480), T helper (Th)1 (SMD: 0.316, CI: 0.185;0.446), Th17 (SMD: 0.439, CI: 0.302;0.577) and immune-associated neurotoxicity (SMD: 0.384, CI: 0.271;0.497). In addition, CRP and 21 different cytokines displayed significantly elevated levels in LC patients compared to NC.

CONCLUSION

LC disease is characterized by IRS activation and increased immune-associated neurotoxicity.

Post-acute sequelae of SARS-CoV-2 cardiovascular symptoms are associated with trace-level cytokines that affect cardiomyocyte function

An estimated 65 million people globally suffer from post-acute sequelae of COVID-19 (PASC), with many experiencing cardiovascular symptoms (PASC-CVS) like chest pain and heart palpitations. This study examines the role of chronic inflammation in PASC-CVS, particularly in individuals with symptoms persisting over a year after infection. Blood samples from three groups-recovered individuals, those with prolonged PASC-CVS and SARS-CoV-2-negative individuals-revealed that those with PASC-CVS had a blood signature linked to inflammation. Trace-level pro-inflammatory cytokines were detected in the plasma from donors with PASC-CVS 18 months post infection using nanotechnology. Importantly, these trace-level cytokines affected the function of primary human cardiomyocytes. Plasma proteomics also demonstrated higher levels of complement and coagulation proteins in the plasma from patients with PASC-CVS. This study highlights chronic inflammation's role in the symptoms of PASC-CVS.

Cluster analysis identifies long COVID subtypes in Belgian patients

Severe acute respiratory syndrome coronavirus infection presents complications known as long COVID, a multisystemic organ disease which allows multidimensional analysis. This study aims to uncover clusters of long COVID cases and establish their correlation with the clinical classification developed at the Clinical Research Unit of Brugmann University Hospital, Brussels. Such an endeavour is instrumental in customizing patient management strategies tailored to the unique needs of each distinct group. A two-stage multidimensional exploratory analysis was performed on a retrospective cohort of 205 long COVID patients, involving a factorial analysis of mixed data, and then hierarchical clustering post component analysis. The study's sample comprised 76% women, with an average age of 44.5 years. Three clinical forms were identified: long, persistent, and post-viral syndrome. Multidimensional analysis using demographic, clinical, and biological variables identified three clusters of patients. Biological data did not provide sufficient differentiation between clusters. This emphasizes the importance of identifying or classifying long COVID patients according to their predominant clinical syndrome. Long COVID phenotypes, as well as clinical forms, appear to be associated with distinct pathophysiological mechanisms or genetic predispositions. This underscores the need for further research.

Global burden of viral infectious diseases of poverty based on Global Burden of Diseases Study 2021

BACKGROUND

Viral infectious diseases of poverty (vIDPs) remain a significant global health challenge. Despite their profound impact, the burden of these diseases is not comprehensively quantified. This study aims to analyze the global burden of six major vIDPs, including coronavirus disease 2019 (COVID-19), HIV/AIDS, acute hepatitis, dengue, rabies, and Ebola virus disease (EVD), using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 (GBD 2021).

METHODS

Following the GBD 2021 framework, we analyzed the incidence, mortality, and disability-adjusted life years (DALYs) of the six vIDPs across 204 countries and territories from 1990 to 2021. We examined the association between the Socio-Demographic Index (SDI) and the burden of vIDPs. All estimates were reported as numbers and rates per 100,000 population, calculated using the Bayesian statistical model employed by GBD 2021, with 95% uncertainty intervals (UI).

RESULTS

In 2021, vIDPs caused approximately 8.7 million deaths and 259.2 million DALYs, accounting for 12.8% and 9.0% of the global all-cause totals, respectively. Globally, the burden of vIDPs varied significantly: COVID-19 caused around 7.9 million (95% UI: 7.5, 8.4) deaths and 212.0 million (95% UI 197.9, 234.7) DALYs in 2021. Acute hepatitis had the second-highest age-standardized incidence rate, with 3411.5 (95% UI: 3201.8, 3631.3) per 100,000 population, while HIV/AIDS had a high age-standardized prevalence rate, with 483.1 (95% UI: 459.0, 511.4) per 100,000 population. Dengue incidence cases rose from 26.5 million (95% UI: 3.9, 51.9) in 1990 to 59.0 million (95% UI: 15.5, 106.9) in 2021. Rabies, although reduced in prevalence, continued to pose a significant mortality risk. EVD had the lowest overall burden but significant outbreak impacts. Age-standardized DALY rates for vIDPs were significantly negatively correlated with SDI: acute hepatitis (r = -0.8, P < 0.0001), rabies (r = -0.7, P < 0.0001), HIV/AIDS (r = -0.6, P < 0.0001), COVID-19 (r = -0.5, P < 0.0001), dengue (r = -0.4, P < 0.0001), and EVD (r = -0.2, P < 0.005).

CONCLUSIONS

VIDPs pose major public health challenges worldwide, with significant regional, age, and gender disparities. The results underscore the need for targeted interventions and international cooperation to mitigate the burden of these diseases. Policymakers can use these findings to implement cost-effective interventions and improve health outcomes, particularly in regions with high or increasing burdens.

Long COVID and gut candidiasis: What is the existing relationship?

Since the beginning of the coronavirus disease (COVID) 2019 pandemic, thousands of articles on the topic have been published, and although there is a growing trend of research on another associated condition, long coronavirus disease, important points still remain to be clarified in this respect. Robust evidence has suggested a relevant link between new clinical discoveries and molecular mechanisms that could be associated with the manifestations of different signs and symptoms involving cases of long COVID. However, one of the existing gaps that requires further investigation concerns a possible relationship between gut candidiasis and long COVID. While recent studies also suggest an interplay between the occurrence of these two conditions, it is not yet fully clear how this may happen, as well as the specifics regarding the possible pathophysiological mechanisms involved. In this connection and with the advent of a potential strengthening of the body of evidence supporting the hypothesis of a link between gut candidiasis and long COVID, a better understanding of the clinical presentation, pathophysiology and clinical management of such a relationship should be essential and useful for both, additional advances towards more targeted research and appropriate case management. Knowing more about the signs, symptoms, and complications associated with cases of long COVID is essential in order to more effectively mitigate the related burden and provide a higher quality of care and life for the affected population. In light of this and the need for better outcomes, here we review and discuss the content on different aspects of long COVID, including its pathophysiology and the existing evidence of a potential relationship between such a condition and gut candidiasis, as well as suggest propositions for future related research.

Effects of an 8-week high-dose vitamin D supplementation on fatigue and neuropsychiatric manifestations in post-COVID syndrome: A randomized controlled trial

AIM

This study evaluated the effectiveness of high-dose vitamin D supplementation in alleviating fatigue and neuropsychiatric symptoms in post-COVID syndrome.

METHODS

In an 8-week, double-blind, randomized, placebo-controlled trial, 80 patients with post-COVID fatigue or neuropsychiatric symptoms were enrolled. Participants were randomly assigned to receive either 60,000 IU of vitamin D weekly (n = 40) or a placebo (n = 40) for 8 weeks. Clinical outcomes were assessed using the 11-item Chalder Fatigue Scale (CFQ-11); 21-item Depression, Anxiety, and Stress Scale (DASS-21); Pittsburgh Sleep Quality Index (PSQI); Addenbrooke's Cognitive Examination III (ACE); and Trail Making Test A and B (TMT-A and TMT-B). Baseline and 8-week measurements of inflammatory markers, including interleukin 6 (IL-6) and C-reactive protein (CRP), were also collected.

RESULTS

Significant improvements were found in the vitamin D group for CFQ (coefficient -3.5, P = 0.024), DASS-anxiety (-2.0, P = 0.011), and ACE (2.1, P = 0.012). No significant differences were observed in PSQI, DASS-depression, TMT, IL-6, or CRP levels. The incidence of adverse events was comparable between groups, with no serious adverse events reported.

CONCLUSION

High-dose vitamin D supplementation may benefit patients with post-COVID syndrome by reducing fatigue, alleviating anxiety, and improving cognitive symptoms, with minimal side effects.

Acute estradiol and progesterone therapy in hospitalized adults to reduce COVID-19 severity: a randomized control trial

COVID-19 outcomes are less severe in women than men suggesting that female sex is protective. The steroids estradiol (E2) and progesterone (P4) promote anti-inflammatory immune responses and their therapeutic use for COVID-19 has been under investigation. The aim of the study was to evaluate the efficacy of a short systemic E2 and P4 combination in mitigating COVID-19 severity in hospitalized men and women. In a phase 2, single center, double blind, randomized placebo-controlled trial, ten male and female participants hospitalized for COVID-19 with scores 3-5 on the 9-point WHO ordinal scale were randomized to receive either (1) E2 cypionate (5 mg, IM) and micronized P4 (200 mg, PO), or (2) placebo-equivalent, in addition to standard of care (SOC). The primary outcome was the proportion of patients whose WHO scores improved to 1-2 on the day of discharge. Secondary outcomes included length of hospital stay (LOS), days on oxygen therapy (DOT), readmission rates (RR), adverse events (AEs), and change in circulating biomarkers using untargeted proteomics and cytokine profiling. There were no significant changes between the groups in primary outcome, LOS, DOT, RR or AEs. The E2P4 group exhibited a decrease in biomarker pathways of respiratory and gastrointestinal disease inflammation, infection by coronavirus, and immune cell trafficking and inflammatory response. A short-term E2P4 treatment in patients hospitalized for COVID-19 decreases biomarkers of inflammation. Considering the availability, low cost, and safety of E2 and P4, our results warrant additional studies to explore their effects in mitigating other viral pandemics. Clinical Trial Registration NCT04865029, ClinicalTrials.gov; (First trial registration 29/04/2021).

Differentiation of Prior SARS-CoV-2 Infection and Postacute Sequelae by Standard Clinical Laboratory Measurements in the RECOVER Cohort

BACKGROUND

There are currently no validated clinical biomarkers of postacute sequelae of SARS-CoV-2 infection (PASC).

OBJECTIVE

To investigate clinical laboratory markers of SARS-CoV-2 and PASC.

DESIGN

Propensity score-weighted linear regression models were fitted to evaluate differences in mean laboratory measures by prior infection and PASC index (≥12 vs. 0). (ClinicalTrials.gov: NCT05172024).

SETTING

83 enrolling sites.

PARTICIPANTS

RECOVER-Adult cohort participants with or without SARS-CoV-2 infection with a study visit and laboratory measures 6 months after the index date (or at enrollment if >6 months after the index date). Participants were excluded if the 6-month visit occurred within 30 days of reinfection.

MEASUREMENTS

Participants completed questionnaires and standard clinical laboratory tests.

RESULTS

Among 10 094 participants, 8746 had prior SARS-CoV-2 infection, 1348 were uninfected, 1880 had a PASC index of 12 or higher, and 3351 had a PASC index of zero. After propensity score adjustment, participants with prior infection had a lower mean platelet count (265.9 × 109 cells/L [95% CI, 264.5 to 267.4 × 109 cells/L]) than participants without known prior infection (275.2 × 109 cells/L [CI, 268.5 to 282.0 × 109 cells/L]), as well as higher mean hemoglobin A1c (HbA1c) level (5.58% [CI, 5.56% to 5.60%] vs. 5.46% [CI, 5.40% to 5.51%]) and urinary albumin-creatinine ratio (81.9 mg/g [CI, 67.5 to 96.2 mg/g] vs. 43.0 mg/g [CI, 25.4 to 60.6 mg/g]), although differences were of modest clinical significance. The difference in HbA1c levels was attenuated after participants with preexisting diabetes were excluded. Among participants with prior infection, no meaningful differences in mean laboratory values were found between those with a PASC index of 12 or higher and those with a PASC index of zero.

LIMITATION

Whether differences in laboratory markers represent consequences of or risk factors for SARS-CoV-2 infection could not be determined.

CONCLUSION

Overall, no evidence was found that any of the 25 routine clinical laboratory values assessed in this study could serve as a clinically useful biomarker of PASC.

PRIMARY FUNDING SOURCE

National Institutes of Health.

The relationship of COVID-19 severity with laboratory findings and neutrophil-to-lymphocyte ratio in patients admitted to a large teaching hospital in Iran: A cross-sectional study

Background and Aims

COVID-19 patients might be admitted to the hospital based on their clinical manifestations or to the intensive care unit (ICU) due to the severity of their symptoms or critical situation. Our main objective was to investigate clinical and demographic factors influencing COVID-19 patients' admission to the ICU and length of stay (LOS) using extracted data from the hospital information systems in Iran.

Methods

The data of hospitalized patients with confirmed COVID-19 were retrieved from the health information system of Imam Khomeini Hospital Complex, Tehran, Iran between March 2020 and February 2022. The primary outcome was the ICU admission, and the secondary outcome was the LOS. The correlation analysis between laboratory findings and demographic data with ICU admission and LOS was done using SPSS 21.0, and p < 0.05 was considered significant.

Results

Of all the 4156 patients, 2391 (57.5%) were male and the mean age was 58.69 ± 8.19 years. Of these, 9.5% of patients were admitted to ICU at any time point during their hospital stay. Age and laboratory variables such as neutrophil-to-lymphocyte ratio (NLR), ALT (U/L), albumin (g/dL), plasma glucose (mg/dL), ferritin levels (ng/mL), and phosphorous levels (mg/dL) shown the significant relationship with ICU admission. Also, being a smoker and having hypoxemia had a significant relationship with longer stays in the hospital. In this study, we validated a cut-off value of 4.819 for NLR, calculated at hospitalization, as a useful predictor of disease progression and occurrence of serious clinical outcomes, such as ICU admission.

Conclusion

The study examined various clinical factors associated with ICU admission in COVID-19 patients. The findings suggest that certain factors can increase the risk of ICU admission and influence the length of hospital stay which should be focused in future studies.

The Significance of Endothelial Dysfunction in Long COVID-19 for the Possible Future Pandemic of Chronic Kidney Disease and Cardiovascular Disease

Various symptoms have been reported to persist beyond the acute phase of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which is referred to as long coronavirus disease 19 (long COVID-19). Over 65 million individuals suffer from long COVID-19. However, the causes of long COVID-19 are largely unknown. Since long COVID-19 symptoms are observed throughout the body, vascular endothelial dysfunction is a strong candidate explaining the induction of long COVID-19. The angiotensin-converting enzyme 2 (ACE2), the entry receptor for SARS-CoV-2, is ubiquitously expressed in endothelial cells. We previously found that the risk factors for atherosclerotic cardiovascular disease (ASCVD) and a history of ASCVD raise the risk of severe COVID-19, suggesting a contribution of pre-existing endothelial dysfunction to severe COVID-19. Here, we show a significant association of endothelial dysfunction with the development of long COVID-19 and show that biomarkers for endothelial dysfunction in patients with long COVID-19 are also crucial players in the development of ASCVD. We consider the influence of long COVID-19 on the development of chronic kidney disease (CKD) and ASCVD. Future assessments of the outcomes of long COVID-19 in patients resulting from therapeutic interventions that improve endothelial function may imply the significance of endothelial dysfunction in the development of long COVID-19.

COVID-19 and Carcinogenesis: Exploring the Hidden Links

The COVID-19 pandemic caused by the SARS-CoV-2 virus has been studied predominantly in terms of its immediate respiratory and systemic effects. However, emerging evidence suggests possible long-term effects, including its role in carcinogenesis. This comprehensive review explores the complex relationship between COVID-19 and cancer development, focusing on immune dysregulation, chronic inflammation, genetic and epigenetic alterations, and the impact of therapeutic interventions. We also focused on the molecular mechanisms by which SARS-CoV-2 may facilitate cancer progression, including the roles of angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), and FURIN. Additionally, we examined the possible carcinogenic effects of long-term COVID-19 treatments and the interaction between co-infections and cancer risk. Our findings highlight the need for increased cancer surveillance in COVID-19 survivors. In the post-COVID-19 period, it can be thought that inflammation associated with excessive cytokine release, especially interleukin-6, genetic and epigenetic changes, and co-infections with oncogenic viruses such as Epstein-Barr virus or human papillomavirus may be effective in the development and progression of cancer. Further research is needed to explain the mechanisms underlying this relationship.

Plasma IL-6 levels and their association with brain health and dementia risk: A population-based cohort study

BACKGROUND

Recent studies have associated immune abnormalities with dementia. IL-6 is a crucial cytokine in inflammatory responses, and recent evidence has linked elevated IL-6 levels to changes in brain structure and cognitive decline. However, the connection between IL-6 levels, cognition, brain volumes, and dementia risk requires exploration in large prospective cohorts.

METHODS

This study utilized a longitudinal cohort from the UK Biobank to analyze the correlation between IL-6 expression levels, cognitive performance, and cortical and subcortical brain volumes through linear regression. Additionally, we assessed the association between IL-6 levels and long-term dementia risk using Cox regression analysis. We also used one-sample Mendelian randomization to analyze the impact of genetic predisposition of dementia on elevated IL-6 levels.

RESULTS

A total of 50,864 participants were included in this study, with 1,391 new cases of all-cause dementia identified. Higher plasma IL-6 levels are associated with cortical and subcortical atrophy in regions such as the fusiform, thalamus proper, hippocampus, and larger ventricle volumes. IL-6 levels are negatively associated with cognitive performance in pair matching, numeric memory, prospective memory, and reaction time tests. Furthermore, elevated IL-6 levels are linked to a 23-35 % increased risk of all-cause dementia over an average follow-up period of 13.2 years. The one-sample Mendelian randomization analysis did not show associations between the genetic predisposition of dementia and elevated IL-6 levels.

CONCLUSIONS

Increased IL-6 levels are associated with worse cognition, brain atrophy, and a heightened risk of all-cause dementia. Our study highlights the need to focus on the role of peripheral IL-6 levels in managing brain health and dementia risk.

Clinical Characterization of New-Onset Chronic Musculoskeletal Pain in Long COVID: A Cross-Sectional Study

Purpose

New-onset chronic musculoskeletal (MSK) pain is one of the common persistent symptoms in Long COVID (LC). This study investigated its clinical characteristics, underlying mechanisms, and impact on function, psychological health, and quality of life.

Patients and Methods

Thirty adults (19 female, 11 male) with LC and new-onset chronic MSK pain underwent clinical examination, Quantitative Sensory Testing (QST), and blood tests for inflammatory markers and completed the following outcome measures: Timed Up and Go test (TUG), handgrip strength test, COVID-19 Yorkshire Rehabilitation Scale (C19-YRS), Brief Pain Inventory (BPI), Pain Self-Efficacy Questionnaire (PSEQ), Pain Catastrophizing Scale (PCS), International Physical Activity Questionnaire-short form (IPAQ-sf), Generalized Anxiety Disorder (GAD-7), Patient Health Questionnaire (PHQ-9), and EuroQol Five Dimensions health-related quality of life (EQ-5D-5L).

Results

New-onset chronic MSK pain was widespread and continuous in nature, and worse in the joints. When compared to normative values reported in the literature: a) QST revealed mechanical hyperalgesia, heightened temporal summation of pain, and hypoesthesia to vibration stimuli, which is strongly suggestive of central sensitization; b) Plasma cytokine assays indicated distinct pro-inflammatory profiles; c) TUG time indicated reduced balance and mobility; d) handgrip strength revealed general weakness; e) physical activity was lower; and f) there were moderate levels of depression and anxiety with lower self-efficacy scores and lower levels of pain catastrophizing. LC symptoms were of moderate severity (44.8/100), moderate functional disability (22.8/50) and severely compromised overall health (2.6/10) when compared to pre-COVID scores.

Conclusion

New-onset chronic MSK pain in LC tends to be widespread, constant, and associated with weakness, reduced function, depression, anxiety, and reduced quality of life. There is associated central sensitization and proinflammatory state in the condition. Further research is essential to explore the longitudinal progression and natural evolution of the new-onset chronic MSK pain in LC.

Addressing Post-Acute COVID-19 Syndrome in Cancer Patients, from Visceral Obesity and Myosteatosis to Systemic Inflammation: Implications in Cardio-Onco-Metabolism

Cardiovascular disease and cancer are the two leading causes of morbidity and mortality in the world. The emerging field of cardio-oncology described several shared risk factors that predispose patients to both cardiovascular disease and cancer. Post-acute COVID-19 syndrome is a chronic condition that occurs in many patients who have experienced a SARS-CoV-2 infection, mainly based on chronic fatigue, sedentary lifestyle, cramps, breathing difficulties, and reduced lung performance. Post-acute COVID-19 exposes patients to increased visceral adiposity, insulin resistance, myosteatosis, and white adipose tissue content (surrounded by M1 macrophages and characterized by a Th1/Th17 phenotype), which increases the risk of cardiovascular mortality and cancer recurrence. In this review, the main metabolic affections of post-acute COVID-19 syndrome in cancer patients at low and high risk of cardiomyopathies will be summarized. Furthermore, several non-pharmacological strategies aimed at reducing atherosclerotic and cardiac risk will be provided, especially through anti-inflammatory nutrition with a low insulin and glycemic index, appropriate physical activity, and immune-modulating bioactivities able to reduce visceral obesity and myosteatosis, improving insulin-related signaling and myocardial metabolism.

Clinical characteristics, anti-SARS-CoV-2 IgG titers, and inflammatory markers in individuals with post-COVID-19 condition in Kenya: a cross-sectional study

Background

Post-coronavirus disease 2019 (post-COVID-19) is associated with considerable morbidity and reduced quality of life. However, studies characterizing the post-COVID-19 condition in Kenya are limited. This study aimed to determine the prevalence of post-COVID-19 condition and determine the clinical characteristics, anti-SARS-CoV-2 IgG titers, and concentrations of inflammatory markers of individuals with post-COVID-19 condition in Kenya.

Methods

This descriptive cross-sectional study was conducted at the Kenyatta University Health Unit, Kenya. Demographic and clinical data were collected using a questionnaire. The serum levels of anti-SARS-CoV-2 antibodies, interleukin 6 (IL-6), and C-reactive protein (CRP) were quantified by enzyme-linked immunosorbent assays. Independent samples t-test was used to compare the anti-SARS-CoV-2 IgG, IL-6, and CRP levels between the participants with and without post-COVID-19 symptoms. The case definition for post-COVID-19 condition was persistence of acute COVID-19 symptoms or emergence of new symptoms 3 months after COVID-19 diagnosis, symptoms lasting for ≥2 months, and absence of any other etiological basis to explain the symptoms.

Results

A total of 189 volunteers were recruited in this study (median age: 21 years, range: 18-71 years; male, 49.2%). Forty participants reported having had at least one COVID-19 positive diagnosis in the past, of which 12 (30%) complained of post-COVID-19 symptoms. Significant differences in the number and duration of symptoms were observed between the individuals with and without post-COVID-19 symptoms (t-statistic = 2.87, p = 0.01; t-statistic = 2.39, p = 0.02, respectively). However, no significant differences in serum levels of anti-SARS-CoV-2 IgG, IL-6, and CRP were observed between the two groups (P = 0.08, 0.9, and 0.28, respectively).

Conclusion

These findings suggest that post-COVID-19 condition is a health concern even for a relatively young population in Kenya and globally. This condition requires more attention and well-designed studies to better define it and identify clinical chemistry markers that can be used for its diagnosis.

Lisinopril increases lung ACE2 levels and SARS-CoV-2 viral load and decreases inflammation but not disease severity in experimental COVID-19

COVID-19 causes more severe and frequently fatal disease in patients with pre-existing comorbidities such as hypertension and heart disease. SARS-CoV-2 virus enters host cells through the angiotensin-converting enzyme 2 (ACE2), which is fundamental in maintaining arterial pressure through the renin-angiotensin system (RAS). Hypertensive patients commonly use medications such as angiotensin-converting enzyme inhibitors (ACEi), which can modulate the expression of ACE2 and, therefore, potentially impact the susceptibility and severity of SARS-CoV-2 infection. Here we assessed whether treatment of ACE2-humanized (K18-hACE2) mice with the ACEi Lisinopril affects lung ACE2 levels and the outcome of experimental COVID-19. K18-hACE2 mice were treated for 21 days with Lisinopril 10 mg/kg and were then infected with 105 PFU of SARS-CoV-2 (Wuhan strain). Body weight, clinical score, respiratory function, survival, lung ACE2 levels, viral load, lung histology, and cytokine (IL-6, IL-33, and TNF-α) levels were assessed. Mice treated with Lisinopril for 21 days showed increased levels of ACE2 in the lungs. Infection with SARS-CoV-2 led to massive decrease in lung ACE2 levels at 3 days post-infection (dpi) in treated and untreated animals, but Lisinopril-treated mice showed a fast recovery (5dpi) of ACE2 levels. Higher ACE2 levels in Lisinopril-treated mice led to remarkably higher lung viral loads at 3 and 6/7dpi. Lisinopril-treated mice showed decreased levels of the pro-inflammatory cytokines IL-6 and TNF-α in the serum and lungs at 6/7dpi. Marginal improvements in body weight, clinical score and survival were observed in Lisinopril-treated mice. No differences between treated and untreated infected mice were observed in respiratory function and lung histology. Lisinopril treatment showed both deleterious (higher viral loads) and beneficial (anti-inflammatory and probably anti-constrictory and anti-coagulant) effects in experimental COVID-19. These effects seem to compensate each other, resulting in marginal beneficial effects in terms of outcome for Lisinopril-treated animals.

Long-term changes in the phenotype and cytokine production of monocytes in COVID-19 recovered and vaccinated individuals

Monocytes play a crucial role in the immune response against pathogens. Here, we sought to determine COVID-19 and the vaccine Gam-COVID-Vac induce long-term changes in the phenotype and cytokine production of circulating monocytes. Monocytes were purified from peripheral blood mononuclear cells of healthy donors who had not had COVID-19 or vaccination, who had received two doses of Gam-COVID-Vac, and who had mild/moderate COVID-19 in the last 6 months and evaluated by flow cytometry. To investigate the effect of SARS-CoV-2 proteins, monocytes were cultured for 2 days with or without stimulation with recombinant SARS-CoV-2 S1 and N peptides. Monocytes obtained from vaccinated and recovered individuals showed increased basal expression of HLA-DR, CD63, CXCR2, and TLR7. We also observed an increased frequency of CD63+ classical monocytes in both groups, as well as an increased frequency of HLA-DR+ non-classical monocytes in the COVID-19-recovered group compared to the control group. Monocytes from vaccinated and recovered donors produced higher basal levels of IL-6, IL-1β, and TNF-α cytokines. Ex vivo stimulation with SARS-CoV-2 antigens induced increased expression of HLA-DR and TLR7 on monocytes obtained from the control group. The challenge with SARS-CoV-2 antigens had no effect on the production of IL-6, IL-1β, and TNF-α cytokines by monocytes. The acquired data offer compelling evidence of enduring alterations in both the phenotype and functional status of circulating monocytes subsequent to vaccination with Gam-COVID-Vac and mild/moderate COVID-19 infection. At least some of these changes appear to be a consequence of exposure to SARS-CoV-2 S1 and N antigens.

Antibody drugs targeting SARS-CoV-2: Time for a rethink?

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) heavily burdens human health. Multiple neutralizing antibodies (nAbs) have been issued for emergency use or tested for treating infected patients in the clinic. However, SARS-CoV-2 variants of concern (VOC) carrying mutations reduce the effectiveness of nAbs by preventing neutralization. Uncoding the mutation profile and immune evasion mechanism of SARS-CoV-2 can improve the outcome of Ab-mediated therapies. In this review, we first outline the development status of anti-SARS-CoV-2 Ab drugs and provide an overview of SARS-CoV-2 variants and their prevalence. We next focus on the failure causes of anti-SARS-CoV-2 Ab drugs and rethink the design strategy for developing new Ab drugs against COVID-19. This review provides updated information for the development of therapeutic Ab drugs against SARS-CoV-2 variants.

Viral respiratory infections and air pollution: A review focused on research in Poland

The COVID-19 pandemic has reinforced an interest in the relationship between air pollution and respiratory viral infections, indicating that their burden can be increased under poor air quality. This paper reviews the pathways through which air pollutants can enhance susceptibility to such infections and aggravate their clinical course and outcome. It also summarizes the research exploring the links between various viral infections and exposure to solid and gaseous pollution in Poland, a region characterized by poor air quality, especially during a heating season. The majority of studies focused on concentrations of particulate matter (PM; 86.7%); the other pollutants, i.e., BaP, benzene, CO, NOx, O3, and SO2, were studied less often and sometimes only in the context of a particular infection type. Most research concerned COVID-19, showing that elevated levels of PM and NO2 correlated with higher morbidity and mortality, while increased PM2.5 and benzo[a]pyrene levels were related to worse clinical course and outcome in hospitalized, regardless of age and dominant SARS-CoV-2 variant. PM10 and PM2.5 levels were also associated with the incidence of influenza-like illness and, along with NO2 concentrations, with a higher rate of children's hospitalizations due to lower respiratory tract RSV infections. Higher levels of air pollutants also increased hospitalization due to bronchitis (PM, NOx, and O3) and emergency department admission due to viral croup (PM10, PM2.5, NOx, CO, and benzene). Although the conducted studies imply only correlations and have other limitations, as discussed in the present paper, it appears that improving air quality through reducing combustion processes in energy production in Poland should be perceived as a part of multilayered protection measures against respiratory viral infections, decreasing the healthcare costs of COVID-19, lower tract RSV infections, influenza, and other respiratory viral diseases prevalent between autumn and early spring, in addition to other health and climate benefits.

Microplastics dysregulate innate immunity in the SARS-CoV-2 infected lung

Introduction

Global microplastic (MP) pollution is now well recognized, with humans and animals consuming and inhaling MPs on a daily basis, with a growing body of concern surrounding the potential impacts on human health.

Methods

Using a mouse model of mild COVID-19, we describe herein the effects of azide-free 1 μm polystyrene MP beads, co-delivered into lungs with a SARS-CoV-2 omicron BA.5 inoculum. The effect of MPs on the host response to SARS-CoV-2 infection was analysed using histopathology and RNA-Seq at 2 and 6 days post-infection (dpi).

Results

Although infection reduced clearance of MPs from the lung, virus titres and viral RNA levels were not significantly affected by MPs, and overt MP-associated clinical or histopathological changes were not observed. However, RNA-Seq of infected lungs revealed that MP exposure suppressed innate immune responses at 2 dpi and increased pro-inflammatory signatures at 6 dpi. The cytokine profile at 6 dpi showed a significant correlation with the 'cytokine release syndrome' signature observed in some COVID-19 patients.

Discussion

The findings are consistent with the recent finding that MPs can inhibit phagocytosis of apoptotic cells via binding of Tim4. They also add to a growing body of literature suggesting that MPs can dysregulate inflammatory processes in specific disease settings.

AH, Storer RJ, Ounjai P, Kanthawee P, Ngamwongsatit N, Kupwiwat R, Kupwiwat C, Brimson JM, Devanga Ragupathi NK, Charuluxananan S, Leelahavanichkul A, Kanjanabuch T, Higgins PG, Badavath VN, Amarasiri M, Verhasselt V, Kicic A, Chatsuwan T, Pirzada K, Jalali F, Reiersen AM, Abe S, Ishikawa H. Early treatment with fluvoxamine, bromhexine, cyproheptadine, and niclosamide to prevent clinical deterioration in patients with symptomatic COVID-19: a randomized clinical trial

Background

Repurposed drugs with host-directed antiviral and immunomodulatory properties have shown promise in the treatment of COVID-19, but few trials have studied combinations of these agents. The aim of this trial was to assess the effectiveness of affordable, widely available, repurposed drugs used in combination for treatment of COVID-19, which may be particularly relevant to low-resource countries.

Methods

We conducted an open-label, randomized, outpatient, controlled trial in Thailand from October 1, 2021, to June 21, 2022, to assess whether early treatment within 48-h of symptoms onset with combinations of fluvoxamine, bromhexine, cyproheptadine, and niclosamide, given to adults with confirmed mild SARS-CoV-2 infection, can prevent 28-day clinical deterioration compared to standard care. Participants were randomly assigned to receive treatment with fluvoxamine alone, fluvoxamine + bromhexine, fluvoxamine + cyproheptadine, niclosamide + bromhexine, or standard care. The primary outcome measured was clinical deterioration within 9, 14, or 28 days using a 6-point ordinal scale. This trial is registered with ClinicalTrials.gov (NCT05087381).

Findings

Among 1900 recruited, a total of 995 participants completed the trial. No participants had clinical deterioration by day 9, 14, or 28 days among those treated with fluvoxamine plus bromhexine (0%), fluvoxamine plus cyproheptadine (0%), or niclosamide plus bromhexine (0%). Nine participants (5.6%) in the fluvoxamine arm had clinical deterioration by day 28, requiring low-flow oxygen. In contrast, most standard care arm participants had clinical deterioration by 9, 14, and 28 days. By day 9, 32.7% (110) of patients in the standard care arm had been hospitalized without requiring supplemental oxygen but needing ongoing medical care. By day 28, this percentage increased to 37.5% (21). Additionally, 20.8% (70) of patients in the standard care arm required low-flow oxygen by day 9, and 12.5% (16) needed non-invasive or mechanical ventilation by day 28. All treated groups significantly differed from the standard care group by days 9, 14, and 28 (p < 0.0001). Also, by day 28, the three 2-drug treatments were significantly better than the fluvoxamine arm (p < 0.0001). No deaths occurred in any study group. Compared to standard care, participants treated with the combination agents had significantly decreased viral loads as early as day 3 of treatment (p < 0.0001), decreased levels of serum cytokines interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β) as early as day 5 of treatment, and interleukin-8 (IL-8) by day 7 of treatment (p < 0.0001) and lower incidence of post-acute sequelae of COVID-19 (PASC) symptoms (p < 0.0001). 23 serious adverse events occurred in the standard care arm, while only 1 serious adverse event was reported in the fluvoxamine arm, and zero serious adverse events occurred in the other arms.

Interpretation

Early treatment with these combinations among outpatients diagnosed with COVID-19 was associated with lower likelihood of clinical deterioration, and with significant and rapid reduction in the viral load and serum cytokines, and with lower burden of PASC symptoms. When started very soon after symptom onset, these repurposed drugs have high potential to prevent clinical deterioration and death in vaccinated and unvaccinated COVID-19 patients.

Funding

Ped Thai Su Phai (Thai Ducks Fighting Danger) social giver group.

Complement dysregulation is a prevalent and therapeutically amenable feature of long COVID

BACKGROUND

Long COVID encompasses a heterogeneous set of ongoing symptoms that affect many individuals after recovery from infection with SARS-CoV-2. The underlying biological mechanisms nonetheless remain obscure, precluding accurate diagnosis and effective intervention. Complement dysregulation is a hallmark of acute COVID-19 but has not been investigated as a potential determinant of long COVID.

METHODS

We quantified a series of complement proteins, including markers of activation and regulation, in plasma samples from healthy convalescent individuals with a confirmed history of infection with SARS-CoV-2 and age/ethnicity/sex/infection/vaccine-matched patients with long COVID.

FINDINGS

Markers of classical (C1s-C1INH complex), alternative (Ba, iC3b), and terminal pathway (C5a, TCC) activation were significantly elevated in patients with long COVID. These markers in combination had a receiver operating characteristic predictive power of 0.794. Other complement proteins and regulators were also quantitatively different between healthy convalescent individuals and patients with long COVID. Generalized linear modeling further revealed that a clinically tractable combination of just four of these markers, namely the activation fragments iC3b, TCC, Ba, and C5a, had a predictive power of 0.785.

CONCLUSIONS

These findings suggest that complement biomarkers could facilitate the diagnosis of long COVID and further suggest that currently available inhibitors of complement activation could be used to treat long COVID.

FUNDING

This work was funded by the National Institute for Health Research (COV-LT2-0041), the PolyBio Research Foundation, and the UK Dementia Research Institute.

Ginseng and ginsenosides on cardiovascular and pulmonary diseases; Pharmacological potentials for the coronavirus (COVID-19)

Since its outbreak in late 2019, the Coronavirus disease 2019 (COVID-19) pandemic has profoundly caused global morbidity and deaths. The COVID-19 pandemic caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has major complications in cardiovascular and pulmonary system. The increased rate of mortality is due to delayed detection of certain biomarkers that are crucial in the development of disease. Furthermore, certain proteins and enzymes in cellular signaling pathways play an important role in replication of SARS-CoV-2. Most cases are mild to moderate symptoms, however severe cases of COVID-19 leads to death. Detecting the level of biomarkers such as C-reactive protein, cardiac troponin, creatine kinase, creatine kinase-MB, procalcitonin and Matrix metalloproteinases helps in early detection of the severity of disease. Similarly, through downregulating Renin-angiotensin system, interleukin, Mitogen-activated protein kinases and Phosphoinositide 3-kinases pathways, COVID-19 can be effectively controlled and mortality could be prevented. Ginseng and ginsenosides possess therapeutic potential in cardiac and pulmonary complications, there are several studies performed in which they have suppressed these biomarkers and downregulated the pathways, thereby inhibiting the further spread of disease. Supplementation with ginseng or ginsenoside could act on multiple pathways to reduce the level of biomarkers significantly and alleviate cardiac and pulmonary damage. Therefore, this review summarizes the potential of ginseng extract and ginsenosides in controlling the cardiovascular and pulmonary diseases by COVID-19.

IL-6 and IL-17 as potential links between pre-existing hypertension and long-term COVID sequelae in patients undergoing hemodialysis: a multicenter cross-sectional study

Long COVID, characterized by persistent symptoms following acute infection, poses a significant health challenge, particularly for patients with pre-existing chronic conditions such as hypertension. We hypothesized that an increase in the production of interleukins (IL)-6 and IL-17 could serve as a potential mechanism linking pre-existing uncontrolled blood pressure (BP) to the occurrence of long-term COVID sequelae in patients undergoing hemodialysis (HD). This cross-sectional study examined serum IL-6 and IL-17 levels in 80 patients undergoing HD, considering preinfection BP, the presence of long-term COVID sequelae, and the time interval after acute COVID-19 infection, which was either 5 or 10 months. Controlled BP was defined as a 3-month average pre-dialysis BP < 140/90 mmHg and post-dialysis < 130/80 mmHg. The findings suggest that the prevalence of long-term COVID sequelae was significantly higher in patients with uncontrolled BP than in the BP-controlled group. Both IL-6 and IL-17 concentrations were also significantly higher in patients with uncontrolled BP compared with the BP-controlled group. The patients with long-term COVID sequelae had higher IL-6 and IL-17 values than the fully recovered patients at both time points, but their concentrations decreased significantly over time. Further research and prospective studies are warranted to validate these findings.

Chronic Thromboembolic Pulmonary Hypertension after Pulmonary Embolism in SARS-CoV-2

INTRODUCTION

Chronic thromboembolic pulmonary disease (CTEPD) consists of persistent pulmonary vascular obstruction on imaging and involves long-term functional limitations, with or without chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to evaluate the incidence and risk factors of both persistent pulmonary vascular defects and CTEPH after hospitalization in patients with COVID-19 and PE during a 2-year follow-up.

METHODS

A prospective observational study was carried out in a tertiary hospital center. Patients were hospitalized between March 2020 and December 2021 with a diagnosis of PE during SARS-CoV-2 infection. Patients received anticoagulant treatment for at least 3 months and were followed up for 2 years. Between the third and fourth months after discharge, all patients were evaluated for the presence of residual thrombotic defects by CTPA and/or perfusion pulmonary scintigraphy. Clinical findings, lung function tests with DLCO, exercise capacity, and echocardiograms were also assessed.

RESULTS

Of the 133 patients included, 18% had persistent thrombotic defects on lung imaging at follow-up. The incidence of CTEPD was 0.75% at 2 years of follow-up. Patients with persistent defects were significantly older, had a higher prevalence of systemic arterial hypertension, higher D-dimer and NT-proBNP levels, and more severe PE at diagnosis. Furthermore, there was a higher prevalence of right ventricular dysfunction on echocardiogram at diagnosis of PE (25.0% vs. 2.7%, p = 0.006). This was the only variable independently related to persistent defects in multivariate analyses (OR: 8.13 [95% CI: 1.82-36.32], p = 0.006).

CONCLUSION

The persistence of thrombotic defects after PE is a common finding after SARS-CoV-2 infection, affecting 18% of the population. However, the incidence of CTEPH appears to be lower (0.75%) in COVID-19-related PE compared to that previously observed in PE unrelated to COVID-19.

Cortical thickness alterations and systemic inflammation define long-COVID patients with cognitive impairment

As the heterogeneity of symptoms is increasingly recognized among long-COVID patients, it appears highly relevant to study potential pathophysiological differences along the different subtypes. Preliminary evidence suggests distinct alterations in brain structure and systemic inflammatory patterns in specific groups of long-COVID patients. To this end, we analyzed differences in cortical thickness and peripheral immune signature between clinical subgroups based on 3 T-MRI scans and signature inflammatory markers in n = 120 participants comprising healthy never-infected controls (n = 30), healthy COVID-19 survivors (n = 29), and subgroups of long-COVID patients with (n = 26) and without (n = 35) cognitive impairment according to screening with Montreal Cognitive Assessment. Whole-brain comparison of cortical thickness between the 4 groups was conducted by surface-based morphometry. We identified distinct cortical areas showing a progressive increase in cortical thickness across different groups, starting from healthy individuals who had never been infected with COVID-19, followed by healthy COVID-19 survivors, long-COVID patients without cognitive deficits (MoCA ≥ 26), and finally, long-COVID patients exhibiting significant cognitive deficits (MoCA < 26). These findings highlight the continuum of cortical thickness alterations associated with COVID-19, with more pronounced changes observed in individuals experiencing cognitive impairment (p < 0.05, FWE-corrected). Affected cortical regions covered prefrontal and temporal gyri, insula, posterior cingulate, parahippocampal gyrus, and parietal areas. Additionally, we discovered a distinct immunophenotype, with elevated levels of IL-10, IFNγ, and sTREM2 in long-COVID patients, especially in the group suffering from cognitive impairment. We demonstrate lingering cortical and immunological alterations in healthy and impaired subgroups of COVID-19 survivors. This implies a complex underlying pathomechanism in long-COVID and emphasizes the necessity to investigate the whole spectrum of post-COVID biology to determine targeted treatment strategies targeting specific sub-groups.

T4 apoptosis in the acute phase of SARS-CoV-2 infection predicts long COVID

Background

As about 10% of patients with COVID-19 present sequelae, it is important to better understand the physiopathology of so-called long COVID.

Method

To this aim, we recruited 29 patients hospitalized for SARS-CoV-2 infection and, by Luminex®, quantified 19 soluble factors in their plasma and in the supernatant of their peripheral blood mononuclear cells, including inflammatory and anti-inflammatory cytokines and chemokines, Th1/Th2/Th17 cytokines, and endothelium activation markers. We also measured their T4, T8 and NK differentiation, activation, exhaustion and senescence, T cell apoptosis, and monocyte subpopulations by flow cytometry. We compared these markers between participants who developed long COVID or not one year later.

Results

None of these markers was predictive for sequelae, except programmed T4 cell death. T4 lymphocytes from participants who later presented long COVID were more apoptotic in culture than those of sequelae-free participants at Month 12 (36.9 ± 14.7 vs. 24.2 ± 9.0%, p = 0.016).

Conclusions

Our observation raises the hypothesis that T4 cell death during the acute phase of SARS-CoV-2 infection might pave the way for long COVID. Mechanistically, T4 lymphopenia might favor phenomena that could cause sequelae, including SARS-CoV-2 persistence, reactivation of other viruses, autoimmunity and immune dysregulation. In this scenario, inhibiting T cell apoptosis, for instance, by caspase inhibitors, could prevent long COVID.

Predicting Factors of Worse Prognosis in COVID-19: Results from a Cross-sectional Study on 52 Inpatients Admitted to the Internal Medicine Department

BACKGROUND

The initial phases of the COVID-19 pandemic posed a real need for clinicians to identify patients at risk of poor prognosis as soon as possible after hospital admission.

AIMS

The study aimed to assess the role of baseline anamnestic information, clinical parameters, instrumental examination, and serum biomarkers in predicting adverse outcomes of COVID-19 in a hospital setting of Internal Medicine.

METHODS

Fifty-two inpatients consecutively admitted to the Unit of Internal Medicine "Baccelli," Azienda Ospedaliero - Universitaria Policlinico of Bari (February 1 - May 31, 2021) due to confirmed COVID-19 were grouped into two categories based on the specific outcome: good prognosis (n=44), patients discharged at home after the acute phase of the infection; poor prognosis, a composite outcome of deaths and intensive care requirements (n=8). Data were extracted from medical records of patients who provided written informed consent to participate.

RESULTS

The two study groups had similar demographic, anthropometric, clinical, and radiological characteristics. Higher interleukin 6 (IL-6) levels and leucocyte count, and lower free triiodothyronine (fT3) levels were found in patients with poor than those with good prognosis. Higher IL-6 levels and leucocyte count, lower fT3 concentration, and pre-existing hypercholesterolemia were independent risk factors of poor outcomes in our study population. A predicting risk score, built by assigning one point if fT3 < 2 pg/mL, IL-6 >25 pg/mL, and leucocyte count >7,000 n/mm3, revealed that patients totalizing at least 2 points by applying the predicting score had a considerably higher risk of poor prognosis than those scoring <2 points (OR 24.35 (1.32; 448), p = 0.03). The weight of pre-existing hypercholesterolemia did not change the risk estimation.

CONCLUSION

Four specific baseline variables, one anamnestic (pre-existing hypercholesterolemia) and three laboratory parameters (leucocyte count, IL-6, and fT3), were significantly associated with poor prognosis as independent risk factors. To prevent adverse outcomes, the updated 4-point score could be useful in identifying at-risk patients, highlighting the need for specific trials to estimate the safety and efficacy of targeted treatments.

Long COVID or Post-COVID-19 Condition: Past, Present and Future Research Directions

The presence of symptoms after an acute SARS-CoV-2 infection (long-COVID) has become a worldwide healthcare emergency but remains underestimated and undertreated due to a lack of recognition of the condition and knowledge of the underlying mechanisms. In fact, the prevalence of post-COVID symptoms ranges from 50% during the first months after the infection up to 20% two-years after. This perspective review aimed to map the existing literature on post-COVID symptoms and to identify gaps in the literature to guide the global effort toward an improved understanding of long-COVID and suggest future research directions. There is a plethora of symptomatology that can be due to COVID-19; however, today, there is no clear classification and definition of this condition, termed long-COVID or post-COVID-19 condition. The heterogeneity in the symptomatology has led to the presence of groups/clusters of patients, which could exhibit different risk factors and different mechanisms. Viral persistence, long-lasting inflammation, immune dysregulation, autoimmune reactions, reactivation of latent infections, endothelial dysfunction and alteration in gut microbiota have been proposed as potential mechanisms explaining the complexity of long-COVID. In such an equation, viral biology (e.g., re-infections, SARS-CoV-2 variants), host biology (e.g., genetics, epigenetics) and external factors (e.g., vaccination) should be also considered. These various factors will be discussed in the current perspective review and future directions suggested.

Assessing the gene expression of the adenosine 5'-monophosphate-activated protein kinase (AMPK) and its relation with the IL-6 and IL-10 plasma levels in COVID-19 patients

BACKGROUND

Metabolic dysregulation and excessive inflammation are implicated in the pathogenesis of the highly infectious disease of coronavirus disease 2019 (COVID-19), which is caused by a newly emerging coronavirus (i.e., severe acute respiratory syndrome-coronavirus 2; SARS-CoV-2). The adenosine 5'-monophosphate-activated protein kinase (AMPK), an energy sensor regulating the metabolic pathways in diverse cells, exerts a regulatory role in the immune system. This study aims to examine the mRNA expression level of AMPK and the plasma levels of interleukin-6 (IL-6) and IL-10 cytokines in patients with different grades of COVID-19.

METHODS

Peripheral blood was collected from 60 patients with COVID-19 (Moderate, severe, and critical). The plasma levels of IL-6 and IL-10 were quantified by enzyme-linked immunosorbent assay (ELISA), and the mRNA expression level of AMPK was determined using real-time PCR.

RESULTS

The results showed that the plasma levels of IL-6 increased significantly in critical and severe patients compared to moderate cases of COVID-19 (P < 0.001). Moreover, IL-10 plasma concentrations were significantly higher in critical and severe cases than in moderate cases of COVID-19 (P < 0.01 and P < 0.05, respectively). Also, the gene expression of AMPK was meaningfully enhanced in critical patients relative to moderate and severe cases of COVID-19, in order (P < 0.001 and P < 0.01, respectively). There was a positive association between AMPK gene expression and plasma levels of IL-6 and IL-10 (P = 0.006, r = 0.348, P = 0.028, r = 0.283, respectively).

CONCLUSION

Increasing AMPK gene expression is likely a necessary effort of the immune system to inhibit inflammation in critical COVID-19. However, this effort seems to be inadequate, probably due to factors that induce inflammation, like erythrocyte sedimentation rate (ESR) and IL-6.

Cytokine storm and translating IL-6 biology into effective treatments for COVID-19

As of May 3, 2023, the Coronavirus disease 2019 (COVID-19) pandemic has resulted in more than 760 million confirmed cases and over 6.9 million deaths. Several patients have developed pneumonia, which can deteriorate into acute respiratory distress syndrome. The primary etiology may be attributed to cytokine storm, which is triggered by the excessive release of proinflammatory cytokines and subsequently leads to immune dysregulation. Considering that high levels of interleukin-6 (IL-6) have been detected in several highly pathogenic coronavirus-infected diseases, such as severe acute respiratory syndrome in 2002, the Middle East respiratory syndrome in 2012, and COVID-19, the IL-6 pathway has emerged as a key in the pathogenesis of this hyperinflammatory state. Thus, we review the history of cytokine storm and the process of targeting IL-6 signaling to elucidate the pivotal role played by tocilizumab in combating COVID-19.

COVID-19 and trained immunity: the inflammatory burden of long covid

Severe COVID-19 elicits excessive inflammation mediated by innate immune cells like monocytes. Recent evidence reveals extensive epigenetic changes in monocytes during recovery from severe COVID-19, including increased chromatin accessibility at genes related to cytokine production and leukocyte activation. These changes likely originate from the reprogramming of upstream hematopoietic stem and progenitor cells (HSPCs) and represent "trained immunity". HSPC-to-monocyte transmission of epigenetic memory may explain the persistence of these monocyte alterations despite their short lifespan. IL-6 appears pivotal for imprinting durable epigenetic modifications in monocytes during acute infection, with IL-1β potentially playing a contributory role. The poised inflammatory phenotype of monocytes post-COVID-19 may drive chronic inflammation and tissue damage, contributing to post-acute sequelae of COVID-19 symptoms. COVID-19 could also exacerbate inflammation-related diseases, such multisystem inflammatory syndromes, by altering innate immune tendencies via hematopoietic epigenetic reprogramming. Further clinical investigations quantifying inflammatory mediators and mapping epigenetic changes in HSPCs/monocytes of recovering patients are warranted. Research should also examine whether COVID-19 elicits transgenerational inheritance of epigenetic alterations. Elucidating mechanisms underlying COVID-19-induced monocyte reprogramming and developing interventions targeting key inflammatory regulators like IL-6 may mitigate the sustained inflammatory burden imposed by the aberrant trained immunity post-COVID-19.

Allergic diseases as risk factors for Long-COVID symptoms: Systematic review of prospective cohort studies

OBJECTIVE

The role of allergy as a risk factor for Long-COVID (LC) is unclear and has not been thoroughly examined yet. We aimed to systematically review and appraise the epidemiological evidence on allergic diseases as risk factors for LC.

DESIGN

This is an initial systematic review. Two reviewers independently performed the study selection and data extraction using Covidence. Risk of bias (RoB) and certainty of evidence (GRADE) were assessed. Random effects meta-analyses were used to pool unadjusted ORs within homogeneous data subsets.

DATA SOURCES

We retrieved articles published between January 1st, 2020 and January 19th, 2023 from MEDLINE via PubMed, Scopus, the WHO-COVID-19 database and the LOVE platform (Epistemonikos Foundation). In addition, citations and reference lists were searched.

ELIGIBILITY CRITERIA

We included prospective cohort studies recruiting individuals of all ages with confirmed SARS-CoV-2 infection that were followed up for at least 12 months for LC symptoms where information on pre-existing allergic diseases was available. We excluded all study designs that were not prospective cohort studies and all publication types that were not original articles.

RESULTS

We identified 13 studies (9967 participants, range 39-1950 per study), all assessed as high RoB, due to population selection and methods used to ascertain the exposures and the outcome. Four studies did not provide sufficient data to calculate Odds Ratios. The evidence supported a possible relationship between LC and allergy, but was very uncertain. For example, pre-existing asthma measured in hospital-based populations (6 studies, 4019 participants) may be associated with increased risk of LC (Odds Ratio 1.94, 95% CI 1.08, 3.50) and findings were similar for pre-existing rhinitis (3 studies, 1141 participants; Odds Ratio 1.96, 95% CI 1.61, 2.39), both very low certainty evidence.

CONCLUSIONS

Pre-existing asthma or rhinitis may increase the risk of LC.

Chronic Fatigue and Dysautonomia following COVID-19 Vaccination Is Distinguished from Normal Vaccination Response by Altered Blood Markers

SARS-CoV-2 mRNA vaccination can entail chronic fatigue/dysautonomia tentatively termed post-acute COVID-19 vaccination syndrome (PACVS). We explored receptor autoantibodies and interleukin-6 (IL-6) as somatic correlates of PACVS. Blood markers determined before and six months after first-time SARS-CoV-2 vaccination of healthy controls (N = 89; 71 females; mean/median age: 39/49 years) were compared with corresponding values of PACVS-affected persons (N = 191; 159 females; mean/median age: 40/39 years) exhibiting chronic fatigue/dysautonomia (≥three symptoms for ≥five months after the last SARS-CoV-2 mRNA vaccination) not due to SARS-CoV-2 infection and/or confounding diseases/medications. Normal vaccination response encompassed decreases in 11 receptor antibodies (by 25-50%, p < 0.0001), increases in two receptor antibodies (by 15-25%, p < 0.0001) and normal IL-6. In PACVS, serological vaccination-response appeared significantly (p < 0.0001) altered, allowing discrimination from normal post-vaccination state (sensitivity = 90%, p < 0.0001) by increased Angiotensin II type 1 receptor antibodies (cut-off ≤ 10.7 U/mL, ROC-AUC = 0.824 ± 0.027), decreased alpha-2B adrenergic receptor antibodies (cut-off ≥ 25.2 U/mL, ROC-AUC = 0.828 ± 0.025) and increased IL-6 (cut-off ≤ 2.3 pg/mL, ROC-AUC = 0.850 ± 0.022). PACVS is thus indicated as a somatic syndrome delineated/detectable by diagnostic blood markers.

Use of Remdesivir in Patients Hospitalized for COVID-19 Pneumonia: Effect on the Hypoxic and Inflammatory State

Remdesivir is one of the most attractive options for patients with hypoxemic respiratory failure due to coronavirus disease 2019 (COVID-19). The aim of our study was to evaluate the effect of remdesivir on the hypoxic and inflammatory state in patients with moderate to severe COVID-19. We retrospectively enrolled 112 patients admitted for COVID-19 pneumonia, requiring low-flow oxygen, 57 treated with remdesivir plus standard of care (SoC) and 55 treated only with SoC that were similar for demographic and clinical data. We evaluated changes in hypoxemia and inflammatory markers at admission (Day 0) and after 5 days of treatment (Day 5) and the clinical course of the disease. From Day 0 to Day 5, the ratio of arterial oxygen partial pressure to fractional inspired oxygen (P/F) increased from 222 ± 62 to 274 ± 97 (p < 0.0001) in the remdesivir group and decreased from 223 ± 62 to 183 ± 76 (p < 0.05) in the SoC group. Interleukine-6 levels decreased in the remdesivir (45.9 to 17.5 pg/mL, p < 0.05) but not in the SoC group. Remdesivir reduced the need for ventilatory support and the length of hospitalization. In conclusion, compared to standard care, remdesivir rapidly improves hypoxia and inflammation, causing a better course of the disease in moderate to severe COVID-19.

Long COVID, the Brain, Nerves, and Cognitive Function

SARS-CoV-2, a single-stranded RNA coronavirus, causes an illness known as coronavirus disease 2019 (COVID-19). Long-term complications are an increasing issue in patients who have been infected with COVID-19 and may be a result of viral-associated systemic and central nervous system inflammation or may arise from a virus-induced hypercoagulable state. COVID-19 may incite changes in brain function with a wide range of lingering symptoms. Patients often experience fatigue and may note brain fog, sensorimotor symptoms, and sleep disturbances. Prolonged neurological and neuropsychiatric symptoms are prevalent and can interfere substantially in everyday life, leading to a massive public health concern. The mechanistic pathways by which SARS-CoV-2 infection causes neurological sequelae are an important subject of ongoing research. Inflammation- induced blood-brain barrier permeability or viral neuro-invasion and direct nerve damage may be involved. Though the mechanisms are uncertain, the resulting symptoms have been documented from numerous patient reports and studies. This review examines the constellation and spectrum of nervous system symptoms seen in long COVID and incorporates information on the prevalence of these symptoms, contributing factors, and typical course. Although treatment options are generally lacking, potential therapeutic approaches for alleviating symptoms and improving quality of life are explored.

Infection, Dysbiosis and Inflammation Interplay in the COVID Era in Children

For over three years, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children and adolescents has generated repercussions, especially a few weeks after infection, for symptomatic patients who tested positive, for asymptomatic ones, or even just the contacts of an infected person, and evolved from severe forms such as multisystem inflammatory syndrome in children (MIS-C) to multifarious clinical manifestations in long COVID (LC). Referred to under the umbrella term LC, the onset of persistent and highly heterogeneous symptoms such as fatigue, post-exertion malaise, cognitive dysfunction, and others have a major impact on the child's daily quality of life for months. The first aim of this review was to highlight the circumstances of the pathophysiological changes produced by COVID-19 in children and to better understand the hyperinflammation in COVID-19 and how MIS-C, as a life-threatening condition, could have been avoided in some patients. Another goal was to better identify the interplay between infection, dysbiosis, and inflammation at a molecular and cellular level, to better guide scientists, physicians, and pediatricians to advance new lines of medical action to avoid the post-acute sequelae of SARS-CoV-2 infection. The third objective was to identify symptoms and their connection to molecular pathways to recognize LC more easily. The fourth purpose was to connect the triggering factors of LC with related sequelae following acute SARS-CoV-2 injuries to systems and organs, the persistence of the virus, and some of its components in hidden reservoirs, including the gut and the central nervous system. The reactivation of other latent infectious agents in the host's immune environments, the interaction of this virus with the microbiome, immune hyperactivation, and autoimmunity generated by molecular mimicry between viral agents and host proteins, could initiate a targeted and individualized management. New high-tech solutions, molecules, probiotics, and others should be discovered to innovatively solve the interplay between RNA persistent viruses, microbiota, and our immune system.

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

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 it has affected about 65 million people. The etiology of LC remains unclear; however, many pathophysiological pathways may be involved, including viral persistence; a chronic, low-grade inflammatory response; immune dysregulation and a defective immune response; the reactivation of latent viruses; autoimmunity; persistent endothelial dysfunction and coagulopathy; gut dysbiosis; hormonal and metabolic 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, although this effort may be hampered by challenges pertaining to the non-specific nature of the majority of clinical manifestations in the LC spectrum, small sample sizes of relevant studies and other methodological issues. 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, the reactivation of herpesviruses and immune dysregulation; biomarkers of endotheliopathy, coagulation and fibrinolysis; microbiota alterations; diverse proteins and metabolites; hormonal and metabolic biomarkers; and cerebrospinal fluid biomarkers. At present, there are only two reviews summarizing relevant biomarkers; however, they do not cover the entire umbrella of current biomarkers, their link to etiopathogenetic mechanisms or 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 pathogenetic mechanisms and the main LC symptomatology in the frame of the epidemiological and clinical aspects of the syndrome and furthermore assess limitations and challenges as well as potential implications in candidate therapeutic interventions.