Elderly people are particularly vulnerable to COVID-19, with a high risk of developing severe disease and a reduced immune response to the COVID-19 vaccine. A randomized, placebo-controlled, double-blind trial to assess the effect of the consumption of the probiotic Loigolactobacillus coryniformis K8 CECT 5711 on the immune response generated by the COVID-19 vaccine in an elderly population was performed. Two hundred nursing home residents >60 yrs that had not COVID-19 were randomized to receive L. coryniformis K8 or a placebo daily for 3 months. All volunteers received a complete vaccination schedule of a mRNA vaccine, starting the intervention ten days after the first dose. Specific IgG and IgA antibody levels were analyzed 56 days after the end of the immunization process. No differences between the groups were observed in the antibody levels. During the intervention, 19 subjects had COVID-19 (11 receiving K8 vs. 8 receiving placebo, p = 0.457). Subgroup analysis in these patients showed that levels of IgG were significantly higher in those receiving K8 compared to placebo (p = 0.038). Among subjects >85 yrs that did not get COVID-19, administration of K8 tended to increase the IgA levels (p = 0.082). The administration of K8 may enhance the specific immune response against COVID-19 and may improve the COVID-19 vaccine-specific responses in elderly populations.

Following the spread of the SARS-CoV-2 coronavirus, an unprecedented burden has been placed on health care systems, with health care workers (HCWs) being most at risk of COVID-19 infection. The effect of the probiotic Loigolactobacillus coryniformis K8 CECT 5711 on frontline HCWs exposed to the virus was studied in a randomized, double-blind, placebo controlled trial. Parameters related to the incidence and severity of COVID-19 as well as the immune response and the side effects of the COVID-19 vaccine were evaluated. For 2 months, a group of 250 front-line HCWs over the age of 20 was randomly allocated to receive either L. coryniformis K8 or a placebo daily. SARS-CoV-2 infection incidence was verified via PCR or antigen test. In those volunteers who were vaccinated during the intervention, serum levels of specific IgG were analyzed at the end of the study. The incidence of COVID-19 infection was very low [IR (SD) = 0.016 (0.011)], and no significant difference was found between the groups [IRR (95% CI): 1.008 (0.140–7.268), p = 0.994]. For immune response analysis, the total sample was divided according to the days between the first dose and the antibody analysis (cutoff points were set at ≤ 56, 57–80 and ≥ 81 days). The specific IgG level decreased over time (p > 0.001). However, in the subgroup of subjects for whom more than 81 days had passed since they received the first dose, the specific IgG levels were significantly higher in the those that took the L. coryniformis K8 [7.12 (0.21)] than in the control group [6.48 (0.19)] (P = 0.040). Interestingly, the subjects who started probiotic consumption before the first dose reported significantly fewer side effects (of any kind) at the 1st dose of the vaccine (OR: 0.524, p = 0.043), specifically less arm pain (OR: 0.467, p = 0.017). In conclusion, the administration of L. coryniformis K8 CECT 5711 to HCWs helps to extend the immune protection generated by the COVID-19 vaccine over time.

Atherosclerosis is a hallmark of cardiovascular disease, and lifestyle strongly impacts its onset and progression. Nutrients have been shown to regulate the miR-17/92 cluster, with a role in endothelial function and atherosclerosis. Choline, betaine, and L-carnitine, found in animal foods, are metabolized into trimethylamine (TMA) by the gut microbiota. TMA is then oxidized to TMAO, which has been associated with atherosclerosis. Our aim was to investigate whether TMAO modulates the expression of the miR-17/92 cluster, along with the impact of this modulation on the expression of target genes related to atherosclerosis and inflammation. We treated HepG-2 cells, THP-1 cells, murine liver organoids, and human peripheral mononuclear cells with 6 µM of TMAO at different timepoints. TMAO increased the expression of all analyzed members of the cluster, except for miR-20a-5p in murine liver organoids and primary human macrophages. Genes and protein levels of SERPINE1 and IL-12A increased. Both have been associated with atherosclerosis and cardiovascular disease (CDVD) and are indirectly modulated by the miR-17-92 cluster. We concluded that TMAO modulates the expression of the miR-17/92 cluster and that such modulation could promote inflammation through IL-12A and blood clotting through SERPINE1 expression, which could ultimately promote atherosclerosis and CVD.

Hydroxytyrosol (HT) from olives and polyphenols from almond skin (ASPs) possess cardioprotective properties. This pilot study evaluates the effect of supplementation with a combination of olive fruit and almond skin extracts on low-density lipoprotein (LDL) cholesterol oxidation, lipid homeostasis, and inflammatory parameters in adults with moderate hypercholesterolemia. A randomized, parallel, double-blind, placebo-controlled pilot study of 8 weeks was performed. The extract group (EG) received the supplement with 7.5 mg HT +210 mg ASPs, and the control group (CG) received a placebo composed of maltodextrin. Oxidized LDL (oxLDL) levels and the oxLDL/LDL ratio were lower in the EG than in the CG after 8 weeks of treatment (18.76 ± 3.91 vs. 10.34 ± 4.22, P < .001 and 0.151 ± 0.025 vs. 0.08 ± 0.023, P < .001, respectively). Interleukin-1β levels were significantly higher in the CG than in the EG at week 4 ( P = .004), IL-6 was significantly higher in the CG than in the EG at week 4 ( P = .049), and IL-10 was significantly increased at week 4 in both groups ( P = .002 for CG and P = .001 for EG). In conclusion, daily consumption of a combination of an olive fruit extract and an almond skin extract for 8 weeks seems to protect LDL from oxidation and to prevent inflammatory status in moderately hypercholesterolemic subjects.