👤 Koen Vercauteren

Studies have shown that sarcopenia and its related parameters are associated with cognition. Preclinical evidence suggests that myokines, such as irisin, Brain-Derived Neurotrophic Factor(BDNF), myostatin and Insulin-like Growth Factor-1(IGF-1) might explain this relationship. This study aimed to explore the associations between sarcopenia-related parameters and cognition, and whether myokines influence this association. Exploratory, cross-sectional analysis of data from the Exercise and Nutrition for Healthy AgeiNg (ENHANce,NCT03649698) study. Participants were older adults(≥65 years) with EWGSOP2-defined sarcopenia. Cognitive functioning was assessed by Mini-Mental State Examination(MMSE), Repeatable Battery for the Assessment of Neuropsychological Status(RBANS), Trail Making Test A&B(TMT), Stroop and Maze Test. Sarcopenia-related parameters were measured: Handgrip Strength, Chair Stand Test, appendicular Lean Mass(aLM), Gait Speed (GS) and Short Physical Performance Battery(SPPB). Serum myokines(IGF-1, irisin, myostatin, BDNF) were determined through ELISA. Associations between cognition and sarcopenia-related parameters were analyzed using multivariable regression, adjusting for potential confounders including myokines. Fifty-eight participants were included in this analysis (76.2 ± 6.7 years, ♀:65.5%). After adjustment for age, sex, body mass index, aLM was associated with MMSE(β = 0.193,p = 0.012), RBANS Total(β = 0.196,p = 0.007) and RBANS Attention(β = 0.215,p = 0.002), CST was associated with RBANS Language(β = -0.314,p = 0.030), SPPB was associated with Maze time(β = -0.364,p = 0.004) and TMT-B (β = -0.333,p = 0.013) and GS was associated with TMT-A(β = -0.324,p = 0.045). After adjustments for BDNF& IGF-1, the association between GS and TMT-A became non-significant. Irisin and myostatin did not influence the sarcopenia-cognition associations. Sarcopenia-related parameters are associated with global and specific cognitive domains. BDNF may, partially, explain the association between muscle mass and MMSE. Additional research with larger sample size is needed to confirm these findings. Show less

Human T-Lymphotropic Virus type-1 (HTLV-1) is a unique retrovirus associated with both leukemogenesis and a specific neuroinflammatory condition known as HTLV-1-Associated Myelopathy (HAM). Currently, most proposed HAM biomarkers require invasive CSF sampling, which is not suitable for large cohorts or repeated prospective screening. To identify non-invasive biomarkers for incident HAM in a large Brazilian cohort of PLwHTLV-1 (n=615 with 6,673 person-years of clinical follow-up), we selected all plasma samples available at the time of entry in the cohort (between 1997-2019), in which up to 43 cytokines/chemokines and immune mediators were measured. Thus, we selected 110 People Living with HTLV-1 (PLwHTLV-1), of which 68 were neurologically asymptomatic (AS) at baseline and 42 HAM patients. Nine incident HAM cases were identified among 68 AS during follow-up. Using multivariate logistic regression, we found that lower IL-10, IL-4 and female sex were independent predictors of clinical progression to definite HAM (AUROC 0.91), and outperformed previously suggested biomarkers age, sex and proviral load (AUROC 0.77). Moreover, baseline IL-10 significantly predicted proviral load dynamics at follow-up in all PLwHTLV-1. In an exploratory analysis, we identified additional plasma biomarkers which were able to discriminate iHAM from either AS (IL6Rα, IL-27) or HAM (IL-29/IFN-λ1, Osteopontin, and TNFR2). In conclusion, female sex and low anti-inflammatory IL-10 and IL-4 are independent risk factors for incident HAM in PLwHTLV-1,while proviral load is not, in agreement with IL-10 being upstream of proviral load dynamics. Additional candidate biomarkers IL-29/IL-6R/TNFR2 represent plausible therapeutic targets for future clinical trials in HAM patients. Show less

Hepatitis C virus (HCV) is a leading cause of chronic liver diseases and the most common indication for liver transplantation in the United States. HCV particles in the blood of infected patients are characterized by heterogeneous buoyant densities, likely owing to HCV association with lipoproteins. However, clinical isolates are not infectious in vitro and the relative infectivity of the particles with respect to their buoyant density therefore cannot be determined, pointing to the need for better in vivo model systems. To analyze the evolution of the buoyant density of in vivo-derived infectious HCV particles over time, we infected immunodeficient human liver chimeric fumaryl acetoacetate hydrolase Similar to the severe combined immunodeficiency disease/Albumin-urokinase plasminogen activator human liver chimeric mouse model, density fractionation of infectious mouse serum showed higher infectivity in the low-density fractions early after infection. However, over the course of the infection, viral particle heterogeneity increased and the overall in vitro infectivity diminished without loss of the human liver graft over time. In mice provided with a sucrose-rich diet we observed a minor shift in HCV infectivity toward lower density that correlated with a redistribution of triglycerides and cholesterol among lipoproteins. Our work indicates that the heterogeneity in buoyant density of infectious HCV particles evolves over the course of infection and can be influenced by diet. Show less