Sphingomyelin Phosphodiesterase Acid-Like 3b is Essential for Toll-Like Receptor 3 Signaling in Human Podocytes.

Recent studies have revealed the importance of cell membrane stability in normal cell function. Sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b), a lipid modifying enzyme that converts sphingomyelin to ceramide in the cell membrane, is expressed in macrophages and regulates Toll-like receptor (TLR) 4 signaling by altering cell membrane fluidity. SMPDL3b is also expressed in human podocytes, which are involved in the pathogenesis of several glomerular diseases such as diabetic kidney disease, focal segmental glomerulosclerosis, and idiopathic nephrotic syndrome in children; however, the role of SMPDL3b in podocyte innate immunity is unclear. As podocytes are equipped with innate immune systems including TLR3, and viral infections often exacerbate proteinuria in children with idiopathic nephrotic syndrome, we hypothesized that changes in SMPDL3b expression levels could affect anti-viral responses via TLR3 signaling in podocytes, consequently impairing normal podocyte function. To examine the role of SMPDL3b in TLR3 signaling in podocytes, we treated conditionally immortalized human podocytes with polyinosinic-polycytidylic acid (poly IC), to activate TLR3 signaling. The cells were then transfected with small interfering RNA against SMPDL3b. Poly IC activated the TLR3 pathway, whereas knockdown of SMPDL3b attenuated poly IC-induced interferon-ß/chemokine C-X-C ligand 10 expression in podocytes. To our knowledge, this is the first report demonstrating SMPDL3b involvement in podocyte innate immunity; these results suggest that SMPDL3b is essential for adequate anti-viral responses in podocytes, possibly by modulating lipid metabolism in the cell membrane.

Real-world clinical outcomes of treatment with casirivimab-imdevimab among patients with mild-to-moderate coronavirus disease 2019 during the Delta variant pandemic

BackgroundMutations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may reduce the efficacy of neutralizing monoclonal antibody therapy against coronavirus disease 2019 (COVID-19). We here evaluated the efficacy of casirivimab-imdevimab in patients with mild-to-moderate COVID-19 during the Delta variant surge in Fukushima Prefecture, Japan. MethodsWe enrolled 949 patients with mild-to-moderate COVID-19 who were admitted to hospital between July 24, 2021 and September 30, 2021. Clinical deterioration after admission was compared between casirivimab-imdevimab users (n = 314) and non-users (n = 635). ResultsThe casirivimab-imdevimab users were older (P < 0.0001), had higher body temperature ([≥] 38{degrees}C) (P < 0.0001) and greater rates of history of cigarette smoking (P = 0.0068), hypertension (P = 0.0004), obesity (P < 0.0001), and dyslipidemia (P < 0.0001) than the non-users. Multivariate logistic regression analysis demonstrated that receiving casirivimab-imdevimab was an independent factor for preventing deterioration (odds ratio 0.448; 95% confidence interval 0.263-0.763; P = 0.0023). Furthermore, in 222 patients who were selected from each group after matching on the propensity score, deterioration was significantly lower among those receiving casirivimab-imdevimab compared to those not receiving casirivimab-imdevimab (7.66% vs 14.0%; p = 0.021). ConclusionThis real-world study demonstrates that casirivimab-imdevimab contributes to the prevention of deterioration in COVID-19 patients after hospitalization during a Delta variant surge. SummaryThis real-world retrospective study demonstrates the contribution of treatment with casirivimab-imdevimab to the prevention of deterioration in patients with mild-to-moderate coronavirus disease 2019 (COVID-19) even during the Delta variant pandemic.

Development and external validation of the DOAT and DOATS scores: simple decision support tools to identify disease progression among nonelderly patients with mild/moderate COVID-19

BACKGROUNDDue to the dissemination of vaccination against severe acute respiratory syndrome coronavirus 2 in the elderly, the virus-susceptible subjects have shifted to unvaccinated non-elderlies. The risk factors of COVID-19 deterioration in non-elderly patients without respiratory failure have not yet been determined. This study was aimed to create simple predicting method to identify such patients who have high risk for exacerbation. METHODSWe analyzed the data of 1,675 patients aged under 65 years who were admitted to hospitals with mild-to-moderate COVID-19. For validation, 324 similar patients were enrolled. Disease progression was defined as administration of medication, oxygen inhalation and mechanical ventilator starting one day or longer after admission. RESULTSThe patients who exacerbated tended to be older, male, had histories of smoking, and had high body temperatures, lower oxygen saturation, and comorbidities such as diabetes/obesity and hypertension. Stepwise logistic regression analyses revealed that comorbidities of diabetes/obesity, age [≥] 40 years, body temperature [≥] 38{degrees}C, and oxygen saturation < 96% (DOATS) were independent risk factors of worsening COVID-19. As a result two predictive scores were created: DOATS score, which includes all the above risk factors; and DOAT score, which includes all factors except for oxygen saturation. In the original cohort, the areas under the receiver operating characteristic curve of the DOATS and DOAT scores were 0.789 and 0.771, respectively. In the validation, the areas were 0.702 and 0.722, respectively. CONCLUSIONWe established two simple prediction scores that can quickly evaluate the risk of progression of COVID-19 in non-elderly, mild/moderate patients. SummaryThe risk stratification models using independent risks, namely comorbidity of diabetes or obesity, age [≥] 40 years, high body temperature [≥] 38{square}, and oxygen saturation < 96%, DOATS and DOAT scores, predicted worsening COVID-19 in patients with mild-to-moderate cases.