The present study was conducted to elucidate the dietary effects of canna starch on the immune functions and intestinal luminal environment in mice. The amylose and resistant starch characteristics were determined for six types of starch, including edible canna. Canna starch was found to be higher in amylose and resistant starch compared with the other starches. BALB/c mice were fed 3.16% (low-canna group) and 6.32% (high-canna group) canna starch for 2 weeks, and then intestinal parameters were measured. Fecal IgA and mucin levels were markedly elevated by canna starch intake. IgA levels in serum and spleen lymphocytes were elevated by canna starch intake in the high-canna group, but not in the low-canna group. When the mice were fed canna starch, the cecum weight increased, and the pH in the cecum decreased. The high-canna group had significantly increased levels of Clostridium subcluster XIVa lactic acid, acetic acid, and n-butyric acid in the cecum compared with the control group. These results suggested that canna starch supplementation changed the intestinal microbiota and enhanced the intestinal immune and barrier functions and cecal organic acids in mice.

(1) Background: Proglucagon-derived peptides (PDGPs) including glucagon (Gcg), GLP-1, and GLP-2 regulate lipid metabolism in the liver, adipocytes, and intestine. However, the mechanism by which PGDPs participate in alterations in lipid metabolism induced by high-fat diet (HFD) feeding has not been elucidated. (2) Methods: Mice deficient in PGDP (GCGKO) and control mice were fed HFD for 7 days and analyzed, and differences in lipid metabolism in the liver, adipose tissue, and duodenum were investigated. (3) Results: GCGKO mice under HFD showed lower expression levels of the genes involved in free fatty acid (FFA) oxidation such as Hsl, Atgl, Cpt1a, Acox1 (p < 0.05), and Pparα (p = 0.05) mRNA in the liver than in control mice, and both FFA and triglycerides content in liver and adipose tissue weight were lower in the GCGKO mice. On the other hand, phosphorylation of hormone-sensitive lipase (HSL) in white adipose tissue did not differ between the two groups. GCGKO mice under HFD exhibited lower expression levels of Pparα and Cd36 mRNA in the duodenum as well as increased fecal cholesterol contents compared to HFD-controls. (4) Conclusions: GCGKO mice fed HFD exhibit a lesser increase in hepatic FFA and triglyceride contents and adipose tissue weight, despite reduced β-oxidation in the liver, than in control mice. Thus, the absence of PGDP prevents dietary-induced fatty liver development due to decreased lipid uptake in the intestinal tract.

Saliva and salivary antimicrobial proteins play important roles in the innate immunity, which prevents infections of orally invading bacteria and viruses. In this study, we compared the secretion rates of salivary lactoferrin (Lac) and lysozyme (Lys) in heat-not-burn (HNB) cigarette smokers and non-smokers. The analysis population for this study included 212 members of the fire department, including 32 HNB cigarette smokers, 17 paper cigarette smokers, 14 combined HNB and paper cigarette smokers, and 149 non-smokers. Salivary Lac and Lys concentrations were assessed using enzyme immunoassay. Saliva secretion was significantly lower among HNB cigarette smokers (p < 0.01) than among non-smokers. Accompanying this result, salivary Lac and Lys secretion rates were significantly lower among smokers, particularly HNB cigarette smokers, than among non-smokers (all p < 0.01). Our findings suggest a possible adverse effect of HNB cigarette on the amount of Lac and Lys released into the oral cavity.

The coronavirus disease 2019 (COVID-19) pandemic has decreased bystander cardiopulmonary resuscitation (BCPR) intervention rates. The purpose of this study was to elucidate the willingness of university freshmen to provide BCPR during the COVID-19 pandemic and the predictors thereof. A cross-sectional survey of 2789 newly enrolled university students was conducted after the end of the sixth wave of the COVID-19 epidemic in Japan; predictors of willingness to provide BCPR were assessed by regression analysis. Of the 2534 participants 1525 (60.2%) were willing to intervene and provide BCPR during the COVID-19 pandemic. Hesitancy due to the anxiety that CPR intervention might result in poor prognosis was a negative predictor of willingness. In contrast, anxiety about the possibility of infection during CPR intervention did not show a negative impact. On the other hand, interest in CPR and willingness to participate in a course, confidence in CPR skills, awareness of automated external defibrillation, and knowledge of CPR during the COVID-19 pandemic, were also positive predictors. This study suggests that the barrier to willingness to intervene with BCPR during a COVID-19 pandemic is not fear of infection, but rather hesitation due to the possibility of poor prognosis from the intervention. The significance of conducting this study during the COVID-19 epidemic is great, and there is an urgent need for measures to overcome hesitation regarding BCPR.

Background: Cactus contains dietary fiber and minerals and is expected to have preventive effects against diabetes, arteriosclerosis, and other diseases. Additionally, cactus intake induces the production of short-chain fatty acids derived from the gut microbiota, which might influence immune functions. In this study, we examined the effects of a cactus (Nopalea cochenillifera: NC)-supplemented diet on lipopolysaccharide (LPS)-induced immune responses and intestinal barrier function. Methods: Male C3H/HeN mice were randomly divided into three groups—no fiber (NF), cellulose-containing fiber (Cellu), and cactus-added (NC) diets—for 6 weeks. The TNF-α and IL-10 responses to LPS, antibody titers, and intestinal barrier function, as well as the fecal microbiota, were analyzed. Results: The plasma TNF-α but not the IL-10 concentrations were significantly higher in the NC group than in the NF and Cellu groups. Furthermore, the plasma IgG antibody titers were significantly higher in the NC group than in the other groups. The NC group showed higher mucin content and IgA antibody titers in their feces compared with the Cellu group. The succinate and lactate contents, which induce a reduction in TNF-α secretion by macrophages, in the cecum of the NC group were significantly lower than those in the Cellu and NF groups. In contrast, the butyrate content was significantly higher in the cecum of the NC group compared to that of the Cellu group, with a significantly higher relative abundance of butyrate-producing bacteria. Conclusions: Taken together, we found that cactus intake regulates innate and adaptive immune function via the gut microbiota in mice. Therefore, cactus supplementation might serve as a strategy to develop novel functional foods with dietary fiber.