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Muscle wasting diseases, such as cancer cachexia and age-associated sarcopenia, have a profound and detrimental impact on functional independence, quality of life, and survival. Our understanding of the underlying mechanisms is currently limited, which has significantly hindered the development of targeted therapies. In this study, we explored the possibility that the streptococcal quorum sensing peptide Competence Stimulating Peptide 7 (CSP-7) might be a previously unidentified contributor to clinical muscle wasting. We found that CSP-7 selectively triggers muscle cell inflammation in vitro, specifically the release of IL-6. Furthermore, we demonstrated that CSP-7 can traverse the gastrointestinal barrier in vitro and is present in the systemic circulation in humans in vivo. Importantly, CSP-7 was associated with a muscle wasting phenotype in mice in vivo. Overall, our findings provide new mechanistic insights into the pathophysiology of muscle inflammation and wasting., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Objectives: Angiotensin-converting enzyme inhibitors (ACEi), angiotensin II receptor blockers (ARBs), and HMG-CoA reductase inhibitors ("statins") have been hypothesized to affect COVID-19 severity. However, up to now, no studies investigating this association have been conducted in the most vulnerable and affected population groups (ie, older adults residing in nursing homes). The objective of this study was to explore the association of ACEi/ARB and/or statins with clinical manifestations in COVID-19-infected older adults residing in nursing homes., Design: We undertook a retrospective multicenter cohort study to analyze the association between ACEi/ARB and/or statin use with clinical outcome of COVID-19. The outcomes were (1) serious COVID-19 defined as long-stay hospital admission or death within 14 days of disease onset, and (2) asymptomatic (ie, no disease symptoms in the whole study period while still being diagnosed by polymerase chain reaction)., Setting and Participants: A total of 154 COVID-19-positive subjects were identified, residing in 1 of 2 Belgian nursing homes that experienced similar COVID-19 outbreaks., Measures: Logistic regression models were applied with age, sex, functional status, diabetes, and hypertension as covariates., Results: We found a statistically significant association between statin intake and the absence of symptoms during COVID-19 (odds ratio [OR] 2.91; confidence interval [CI] 1.27-6.71), which remained statistically significant after adjusting for covariates (OR 2.65; CI 1.13-6.68). Although the effects of statin intake on serious clinical outcome were in the same beneficial direction, these were not statistically significant (OR 0.75; CI 0.24-1.87). There was also no statistically significant association between ACEi/ARB and asymptomatic status (OR 2.72; CI 0.59-25.1) or serious clinical outcome (OR 0.48; CI 0.10-1.97)., Conclusions and Implications: Our data indicate that statin intake in older, frail adults could be associated with a considerable beneficial effect on COVID-19 clinical symptoms. The role of statins and renin-angiotensin system drugs needs to be further explored in larger observational studies as well as randomized clinical trials., (Copyright © 2020 AMDA – The Society for Post-Acute and Long-Term Care Medicine. All rights reserved.)

Skeletal muscle makes up the largest part of human body mass and a good maintenance of this organ is essential for general health. In accordance, muscle wasting, a frequent phenomenon in many diseases, is associated with functional decline and a decrease in quality of life. Unfortunately, due to a lack of knowledge of the underlying pathophysiology, no targeted therapies exist today to encounter muscle wasting. Recent studies suggest a role for the gut microbiome in muscle wasting, without the mediators of this gut-muscle axis being identified. Here we evaluated the possible effects of 75 quorum sensing molecules (QSM), traditionally only seen as intra-bacterial communication molecules, on C2C12 muscle cells, studying viability, differentiation, inflammation, mitochondrial changes and protein degradation as biological outcomes. The responses were evaluated using different approaches: median absolute deviation, quartiles, strictly standardized mean difference and robust strictly standardized mean difference. This study resulted in 30 QSM, with effects observed on C2C12 cells. Known producers of the 27 peptide QSM belong to species of the genus Staphylococcus, Streptococcus, Enterococcus, Bacillus, Lactobacillus and Escherichia, while the 3 non-peptide QSM are produced by a broad range of Gram-positive and Gram-negative bacteria. Altogether, these proof-of-concept findings provide the first evidence that QSM produced by microbiota play a role in the gut-muscle axis, opening new perspectives for diagnostic and therapeutic targets in muscle wasting diseases., (Copyright © 2019 Elsevier B.V. All rights reserved.)