Limosilactobacillus reuteri DSM 17938 supplementation and SARS-CoV-2 specific antibody response in healthy adults: a randomized, triple-blinded, placebo-controlled trial.

Studies have shown that probiotics can decrease the symptoms of respiratory tract infections as well as increase antibody responses following certain vaccinations. We examined the effect of probiotic supplementation on anti-SARS-CoV-2 specific antibody responses upon SARS-CoV-2 infection as well as after COVID-19 vaccination. In this randomized, triple-blinded, placebo-controlled intervention study with a parallel design, 159 healthy adults without prior SARS-CoV-2 infection or COVID-19 vaccination and any known risk factors for severe COVID-19 were randomly allocated into two study arms. The active treatment arm consumed a probiotic product containing a minimum of 1 × 108 colony-forming units of Limosilactobacillus reuteri DSM 17938 + 10 µg vitamin D3 twice daily for 6 months. The placebo arm consumed identical tablets containing only 10 µg vitamin D3. Anti-SARS-CoV-2 specific antibodies and virus neutralizing antibody titers were analyzed from blood samples collected at baseline, after 3 months, and after 6 months. Differences in serum antibody titers between the two study arms were tested with independent t-test using log-transformed values. In the intention-to-treat (ITT) analysis, SARS-CoV-2 infected individuals in the active treatment arm (n = 6) tended to have higher serum anti-spike IgG (609 [168-1480] BAU/ml vs 111 [36.1-1210] BAU/ml, p = 0.080) and anti-receptor binding domain (RBD) IgG (928 [212-3449] BAU/ml vs (83.7 [22.8-2094] BAU/ml, p = 0.066) levels than individuals in the placebo arm (n = 6). Considering individuals who were fully vaccinated with mRNA-based COVID-19 vaccines, the active treatment arm (n = 10) exhibited significantly higher serum levels of anti-RBD IgA (135 [32.9-976] BAU/ml vs 61.3 [26.7-97.1] BAU/ml, p = 0.036) than the placebo arm (n = 7) >28 days postvaccination. Supplementation with specific probiotics might improve the long-term efficacy of mRNA-based COVID-19 vaccines via enhanced IgA response.

Adiponectin receptor agonist AdipoRon ameliorates renal inflammation in diet-induced obese mice and endotoxin-treated human glomeruli ex vivo.

AIMS/HYPOTHESIS: Chronic low-grade inflammation with local upregulation of proinflammatory molecules plays a role in the progression of obesity-related renal injury. Reduced serum concentration of anti-inflammatory adiponectin may promote chronic inflammation. Here, we investigated the potential anti-inflammatory and renoprotective effects and mechanisms of action of AdipoRon, an adiponectin receptor agonist. METHODS: Wild-type DBA/2J mice were fed with high-fat diet (HFD) supplemented or not with AdipoRon to model obesity-induced metabolic endotoxaemia and chronic low-grade inflammation and we assessed changes in the glomerular morphology and expression of proinflammatory markers. We also treated human glomeruli ex vivo and human podocytes in vitro with AdipoRon and bacterial lipopolysaccharide (LPS), an endotoxin upregulated in obesity and diabetes, and analysed the secretion of inflammatory cytokines, activation of inflammatory signal transduction pathways, apoptosis and migration. RESULTS: In HFD-fed mice, AdipoRon attenuated renal inflammation, as demonstrated by reduced expression of glomerular activated NF-κB p65 subunit (NF-κB-p65) (70%, p < 0.001), TNFα (48%, p < 0.01), IL-1ß (51%, p < 0.001) and TGFß (46%, p < 0.001), renal IL-6 and IL-4 (21% and 20%, p < 0.05), and lowered glomerular F4/80-positive macrophage infiltration (31%, p < 0.001). In addition, AdipoRon ameliorated HFD-induced glomerular hypertrophy (12%, p < 0.001), fibronectin accumulation (50%, p < 0.01) and podocyte loss (12%, p < 0.001), and reduced podocyte foot process effacement (15%, p < 0.001) and thickening of the glomerular basement membrane (18%, p < 0.001). In cultured podocytes, AdipoRon attenuated the LPS-induced activation of the central inflammatory signalling pathways NF-κB-p65, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38-MAPK) (30%, 36% and 22%, respectively, p < 0.001), reduced the secretion of TNFα (32%, p < 0.01), and protected against podocyte apoptosis and migration. In human glomeruli ex vivo, AdipoRon reduced the LPS-induced secretion of inflammatory cytokines IL-1ß, IL-18, IL-6 and IL-10. CONCLUSIONS/INTERPRETATION: AdipoRon attenuated the renal expression of proinflammatory cytokines in HFD-fed mice and LPS-stimulated human glomeruli, which apparently contributed to the amelioration of glomerular inflammation and injury. Mechanistically, based on assays on cultured podocytes, AdipoRon reduced LPS-induced activation of the NF-κB-p65, JNK and p38-MAPK pathways, thereby impelling the decrease in apoptosis, migration and secretion of TNFα. We conclude that the activation of the adiponectin receptor by AdipoRon is a potent strategy to attenuate endotoxaemia-associated renal inflammation.