Plasma extracellular vesicles in people living with HIV and type 2 diabetes are related to microbial translocation and cardiovascular risk

HIV and type 2 diabetes (T2D) are both associated with gut microbiota alterations, low-grade endotoxemia and increased cardiovascular risk. We investigated the potential role of plasma extracellular vesicles (EVs) in relation to these processes. Plasma EVs were isolated by size exclusion chromatography in fasting individuals with HIV and T2D (n = 16), T2D only (n = 14), HIV only (n = 20) or healthy controls (n = 19), and characterized by transmission electron microscopy, western blot, nanoparticle tracking analysis and quantitative proteomics. The findings were compared to gut microbiota alterations, lipopolysaccharide levels and cardiovascular risk profile. Individuals with concomitant HIV and T2D had higher plasma EV concentration, which correlated closely with plasma lipopolysaccharides, triglycerides and Framingham score, but not with gut microbiota alterations. Proteomic analyses identified 558 human proteins, largely related to cardiometabolic disease genes and upstream regulation of inflammatory pathways, including IL-6 and IL-1 beta, as well as 30 bacterial proteins, mostly from lipopolysaccharide-producing Proteobacteria. Our study supports that EVs are related to microbial translocation processes in individuals with HIV and T2D. Their proteomic content suggests a contributing role in low-grade inflammation and cardiovascular risk development. The present approach for exploring gut-host crosstalk can potentially identify novel diagnostic biomarkers and therapeutic targets.Peer reviewe

Circulating markers of extracellular matrix remodelling in severe COVID-19 patients

Background Abnormal remodelling of the extracellular matrix (ECM) has generally been linked to pulmonary inflammation and fibrosis and may also play a role in the pathogenesis of severe COVID-19. To further elucidate the role of ECM remodelling and excessive fibrogenesis in severe COVID-19, we examined circulating levels of mediators involved in various aspects of these processes in COVID-19 patients. Methods Serial blood samples were obtained from two cohorts of hospitalised COVID-19 patients (n = 414). Circulating levels of ECM remodelling mediators were quantified by enzyme immunoassays in samples collected during hospitalisation and at 3-month follow-up. Samples were related to disease severity (respiratory failure and/or treatment at the intensive care unit), 60-day total mortality and pulmonary pathology after 3-months. We also evaluated the direct effect of inactivated SARS-CoV-2 on the release of the different ECM mediators in relevant cell lines. Results Several of the measured markers were associated with adverse outcomes, notably osteopontin (OPN), S100 calcium-binding protein A12 and YKL-40 were associated with disease severity and mortality. High levels of ECM mediators during hospitalisation were associated with computed tomography thorax pathology after 3-months. Some markers (i.e. growth differential factor 15, galectin 3 and matrix metalloproteinase 9) were released from various relevant cell lines (i.e. macrophages and lung cell lines) in vitro after exposure to inactivated SARS-CoV-2 suggesting a direct link between these mediators and the causal agent of COVID-19. Conclusion Our findings highlight changes to ECM remodelling and particularly a possible role of OPN, S100A12 and YKL-40 in the pathogenesis of severe COVID-19

Respiratory dysfunction three months after severe COVID-19 is associated with gut microbiota alterations

Background: Although coronavirus disease 2019 (COVID-19) is primarily a respiratory infection, mounting evidence suggests that the gastrointestinal (GI) tract is involved in the disease, with gut barrier dysfunction and gut microbiota alterations being related to disease severity. Whether these alterations persist and are related to long-term respiratory dysfunction remains unknown. Methods: Plasma was collected during hospital admission and after three months from the NOR-Solidarity trial (n = 181) and analysed for markers of gut barrier dysfunction and inflammation. At the three-month follow-up, pulmonary function was assessed by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO ). Rectal swabs for gut microbiota analyses were collected (n = 97) and analysed by sequencing the 16S rRNA gene. Results: Gut microbiota diversity was reduced in COVID-19 patients with respiratory dysfunction, defined as DLCO below the lower limit of normal three months after hospitalisation. These patients also had an altered global gut microbiota composition, with reduced relative abundance of 20 bacterial taxa and increased abundance of five taxa, including Veillonella, potentially linked to fibrosis. During hospitalisation, increased plasma levels of lipopolysaccharide-binding protein (LBP) were strongly associated with respiratory failure, defined as pO2 /fiO2 -(P/F ratio)Respiratory dysfunction three months after severe COVID-19 is associated with gut microbiota alterationsacceptedVersio

Inflammasome activation, gut microbiota and comorbidities in HIV and COVID-19

Despite antiretroviral treatment people with HIV still have a lower life expectancy and increased risk of non-communicable comorbidities such as cardiovascular diseases. Several mechanisms including chronic immune activation, inflammation and traditional risk factors contribute, but exact mechanisms remain elusive. Altered gut microbiota is seen in many diseases including HIV, and lately also COVID-19. Tryptophan metabolism through the kynurenine pathway is of importance in the interplay between microbiota and the immune system. Inflammasome activation is central in the atherogenic pathogenesis, and leads to the release of the proinflammatory cytokines IL-1 and IL-18. These cytokines are tightly regulated, and markers of this activation can be analyzed in plasma. This thesis aimed to elucidate mechanisms related to microbiota, inflammasome activation and cardiovascular involvement in the RNA viral diseases HIV and Covid-19. The main findings were that patients that had both HIV and Type 2 diabetes had a reduced gut microbial diversity, higher levels of inflammation and a higher Kynurenine/Tryptophan ratio. Also, tryptophan metabolism was associated with endothelial dysfunction. Furthermore, in a nested case control study, markers of IL-1 activity predicted myocardial infarction in HIV patients up to 10 years before the insult, suggesting the IL-1 system could be an important target for preventive intervention. In Covid-19 disease respiratory symptoms are most common, but the gut and heart is also affected. In a longitudinal observational study of hospitalized patients with COVID-19, those with cardiac involvement had higher levels of LPS binding Protein and IL-18 suggesting a gut-heart axis in Covid-19, possibly involving inflammasome activation, but further studies are needed

Prevalence of hepatitis B & hepatitis C virus infections in potential blood donors in rural Vietnam

Safe blood and blood products should be offered to all patients in need for blood transfusion. The objectives of the present study were to establish prevalence estimates for hepatitis B and hepatitis C virus infections as a foundation for safe blood transfusion in rural Vietnam, and to check the accuracy of the laboratory analysis used for hepatitis testing of blood donors in Vietnam. A cross-sectional study was conducted in two rural communities in Quang Tri, Vietnam. A total of 1,200 blood samples collected from potential blood donors were tested by an enzyme immunoassay technique (EIA) for detection of hepatitis surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc), and antibodies to hepatitis C antigen (anti-HCV). The EIA test outcome was validated by a chemiluminescent micro particle immunoassay technique (CMIA). Results: The prevalence of HBsAg and anti-HBc in the study population was 11.4 per cent (95% CI 9.6 - 13.2) and 51.7 per cent (95% CI 48.8 - 54.5), respectively, the prevalences being higher in males than females. The prevalence of anti-HCV was 0.17 per cent. The test agreement between the EIA and CMIA techniques was high both for HBsAg detection (κ = 0.91; 95% CI: 0.83 - 0.99) and for anti-HBc detection (κ = 0.89; 95% CI 0.81 - 0.97). Compared to CMIA results, the positive and negative predictive values of the EIA tests were found to be 94.9 per cent (95% CI 87.5 - 98.6) and 97.5 per cent (95% CI 86.8 - 99.9) for HBsAg, and 92.4 per cent (95% CI 84.2 - 97.2) and 100 per cent (95% CI 91.2 - 100) for anti-HBc. Interpretation & conclusions: The study shows that hepatitis B virus infection is endemic in rural areas of Vietnam and that almost half of the population is or has been infected. Hepatitis C infection is rare, but false negative test results cannot be ruled out. Also, the results indicate that the EIA performance in blood donor screening in Vietnam may be sub-optimal, missing 2.5 per cent of hepatitis B virus carriers and falsely excluding more than 7 per cent of blood donors. As the prevalence of hepatitis B infection is high, occult hepatitis B infection may represent a threat to safe blood transfusion. Therefore, nucleic acid amplification testing for HBV should be considered for blood donor screening in Vietnam

Soluble T-Cell Immunoglobulin Mucin Domain-3 Is Associated With Hepatitis C Virus Coinfection and Low-Grade Inflammation During Chronic Human Immunodeficiency Virus Infection

Abstract Background In well treated human immunodeficiency virus infection (HIV), there is a residual immune activation and immune exhaustion that may contribute to increased risk of comorbidities. T-cell immunoglobulin mucin domain-3 (Tim-3) is an inhibitory molecule involved in HIV-associated T-cell dysfunction. The Tim-3 can be cleaved to soluble Tim-3 (sTim-3) that may serve as a soluble marker of immune exhaustion. Methods We measured sTim-3 with enzyme-linked immunosorbent assay DuoSets in a cross-sectional cohort of 1010 people with HIV (PWH) on antiretroviral therapy (ART), and 76 controls from the Copenhagen Co-Morbidity in HIV Infection (COCOMO) study, and in a longitudinal cohort of 60 PWH before and during ART. Results In the cross-sectional cohort, levels of sTim-3 were elevated in PWH on ART compared with controls, especially in hepatitis C virus (HCV)-coinfected individuals, and were associated with HCV viremia and inflammation. In the longitudinal cohort, pretreatment sTim-3 correlated with HIV viral load and decreased after ART initiation. Pretreatment sTim-3 correlated inversely with CD4 counts, but it did not predict immunological response in multivariable analyses. Conclusions Levels of sTim-3 decreased after ART initiation. In a cross-sectional cohort, levels of sTIM-3 were higher in PWH than in controls and were independently associated with HCV coinfection and high-sensitivity C-reactive protein, representing a potential link between immune exhaustion, inflammation, and risk of comorbidities

Chronic HIV Infection Increases Monocyte NLRP3 Inflammasome-Dependent IL-1α and IL-1β Release

Antiretroviral treatment (ART) has converted HIV from a lethal disease to a chronic condition, yet co-morbidities persist. Incomplete immune recovery and chronic immune activation, especially in the gut mucosa, contribute to these complications. Inflammasomes, multi-protein complexes activated by innate immune receptors, appear to play a role in these inflammatory responses. In particular, preliminary data indicate the involvement of IFI16 and NLRP3 inflammasomes in chronic HIV infection. This study explores inflammasome function in monocytes from people with HIV (PWH); 22 ART-treated with suppressed viremia and 17 untreated PWH were compared to 33 HIV-negative donors. Monocytes were primed with LPS and inflammasomes activated with ATP in vitro. IFI16 and NLRP3 mRNA expression were examined in a subset of donors. IFI16 and NLRP3 expression in unstimulated monocytes correlated negatively with CD4 T cell counts in untreated PWH. For IFI16, there was also a positive correlation with viral load. Monocytes from untreated PWH exhibit increased release of IL-1α, IL-1β, and TNF compared to treated PWH and HIV-negative donors. However, circulating monocytes in PWH are not pre-primed for inflammasome activation in vivo. The findings suggest a link between IFI16, NLRP3, and HIV progression, emphasizing their potential role in comorbidities such as cardiovascular disease. The study provides insights into inflammasome regulation in HIV pathogenesis and its implications for therapeutic interventions