Evaluation of the Immunoregulatory Capacities of Feed Microbial Materials in Porcine Intestinal Immune and Epithelial Cells

The establishment of drug-free feeding systems has been required for secure and healthy livestock production. Although functional feed materials containing microorganisms as alternatives to enhance intestinal immunity are expected to be beneficial for reducing diarrhoea caused by pathogens in weaned piglets, the effects of such materials on porcine intestinal cells have not been investigated in detail. Therefore, this work evaluated the immunoregulatory functions of microbial feed materials in porcine intestinal immune and epithelial cells. Porcine immune cells isolated from Peyer’s patches and mesenteric lymph nodes were stimulated with six different feed materials containing microorganisms, and evaluated for lymphocyte mitogenicity and cytokine inductions. In addition, porcine intestinal epithelial cells were stimulated with the materials before treatment with heat-killed enterotoxigenic Escherichia coli (ETEC), and analyzed for the proinflammatory cytokine expressions. The material containing Bifidobacterium thermophilum significantly augmented lymphocytes’ mitogenicity and also induced a high expression of IL-2, IL-6 and IFN-γ in immune cells, and inhibited ETEC-induced overexpression of IL-6 and IL-8 via regulation of Toll-like receptor signaling. These results suggest that this feed material stimulates intestinal epithelial and immune cells to exert immunoregulation, suggesting that this feed is expected to contribute to promoting the health of piglets without using antimicrobial feed materials.

Alterations of Blood Immune Cells in Elderly Patients with COVID-19 and with or without Pre-Existing Type 2 Diabetes

Elderly individuals, especially those with pre-existing conditions like type 2 diabetes mellitus (T2DM), have a high risk for developing severe cases of COVID-19. The aim of this work was to characterize the alterations of blood immune cells (BIC) in patients with symptomatic COVID-19 and confirmed SARS-CoV-2 infection, ≥60 years and who needed hospitalization in the Centro de Salud Hospital of Tucuman, Argentina, during the second peak of the pandemic in Argentina. Ten patients were enrolled from December 2020 to May 2021. Blood samples were taken at the time of admission (day 0) and five days after (day 5) for routine laboratory tests and the characterization of BIC by flow cytometry. Most of the patients were men (70%) aged between 60 and 78 years. The 70% of patients had T2DM while 50% had arterial hypertension. At day 0, all the patients had increased neutrophils and inflammatory markers (C reactive protein and D-dimers) and reduced numbers of lymphocytes, HLA-DRhi monocytes, CD16+CD56+ NK cells, CD3+HLA−DR+CD25+ cells, CD4+ and CD8+ T cells in blood. Patients received a standard treatment for COVID-19 care (O2, corticosteroids and antibiotics). The hospital treatment normalized the levels of BIC (day 5) in 30% of patients who were those with no comorbidities. In patients with T2DM, BIC recovery was variable. In T2DM patients who required administration of plasma (30%), prolonged O2 therapy (40%) or referral to the intensive care unit (10%) significant reductions of CD16+CD56+, CD3+HLA−DR+CD25+, CD4+ and CD8+ cells were observed between days 0 and 5. In line with previous studies, our results show that absolute counts of major lymphocyte subsets in blood are significantly and substantially decreased during the course of severe COVID-19 disease in elderly patients. These BIC alterations may persist despite clinical care in elderly patients with T2DM. Further studies are needed to investigate the utility of early lymphocyte subset measurements as prognostic biomarkers of disease severity, mortality, and response to treatment in COVID-19 elderly patients with T2DM.