The coronavirus disease 2019 (COVID-19) vaccination campaign has progressed worldwide. Rare but severe adverse events of COVID-19 vaccination such as anaphylaxis and myocarditis have begun to be noticed. Of note, several cases of new-onset antineutrophil cytoplasmic antibody-associated vasculitis (AAV) after COVID-19 mRNA vaccination have been reported. In contrast, relapse of AAV in remission has not been recognized enough as an adverse outcome of COVID-19 vaccination. We report, to the best of our knowledge, a first case of renal-limited AAV in remission using every 6-month rituximab administration that relapsed with pulmonary hemorrhage, but not glomerulonephritis, following the first dose of the COVID-19 vaccine. Notably, the patient received the COVID-19 vaccine more than 6 months after the last dose of rituximab according to the recommendations. Ironically, his CD19 positive B cell counts were found to be increased after admission, indicating that our case might have been prone to relapse after COVID-19 vaccination. Although our case cannot establish causality between AAV relapse and COVID-19 mRNA vaccination, a clinical vigilance for relapse of AAV especially in patients undergoing rituximab maintenance therapy following COVID-19 vaccination should be maintained. Furthermore, the elapsed time between rituximab administration and COVID-19 mRNA vaccination should be carefully adjusted based on AAV disease-activity (Nishioka et al. Front Med 2022. in press).

The purpose of the present study was to test our hypothesis that intestinal nicotinamide phosphoribosyltransferase (NAMPT)-mediated nicotinamide adenine dinucleotide (NAD+) biosynthesis plays a pivotal role in whole-body energy and glucose metabolism. To this end, we generated a new mouse model, namely intestinal epithelial cell-specific Nampt knockout (INKO) mice. Under regular chow diet, deletion of intestinal epithelial NAMPT did not affect body weight gain, food intake, or whole-body energy expenditure, suggesting that intestinal epithelial NAMPT deficiency had no significant impacts on overall energy intake or expenditure. However, INKO mice displayed reduced early-phase insulin secretion and postprandial hyperglycemia, at least partly due to diminished glucagon-like peptide-1 (GLP-1) production. In addition, we found that diet-induced obese mice had impaired intestinal NAMPT-mediated NAD+ biosynthesis, associated with impaired GLP-1 production and whole-body glucose metabolism, similar to the INKO mice. Finally, administration of a key NAD+ intermediate, nicotinamide mononucleotide, to INKO and diet-induced obese mice, restored ileal NAD+ levels and obesity-associated metabolic derangements, manifested by an impairment in GLP-1 production as well as postprandial hyperglycemia. Taken together, our study provides a new understanding of the role of intestinal NAMPT-mediated NAD+ biosynthesis in energy and glucose metabolism, and therapeutic insights into intestinal NAD+ biology related to obesity-associated dysregulation of GLP-1 production and postprandial hyperglycemia (Nagahisa, Yamaguchi et al. Endocrinology. 2022). A future study using INKO mice to investigate if diminished GLP-1 production is involved in obesity-associated hypertension is warranted.

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Patients with end-stage renal disease are less likely to choose peritoneal dialysis (PD) as renal replacement therapy (RRT). The reasons for this biased selection are still poorly understood. In this study, we evaluated the effect of the timing of RRT education on PD selection. This single-center retrospective observational study included patients who initiated maintenance dialysis at our hospital between April 2014 and July 2021. A logistic regression analysis was performed to investigate the association of RRT education timing with PD selection. Among the 355 participants (median age [IQR] 70 (59–79) years; 28.7% female), 53 patients (14.9%) and 302 patients (85.1%) selected PD and hemodialysis, respectively. Multivariate analysis demonstrated that high estimated glomerular filtration (eGFR) at RRT education positively predicted PD selection (p < 0.05), whereas old age (p < 0.01) and high Charlson comorbidity index (p < 0.05) were negative predictors of PD selection. Female sex (p = 0.44), welfare public assistance (p = 0.78), living alone (p = 0.25), high geriatric nutritional risk index (p = 0.10) and high eGFR at first visit to the nephrology department (p = 0.83) were not significantly associated with PD selection. Late RRT education could increase the biased selection of dialysis modality.