Senescence-associated inflammation and inhibition of adipogenesis in subcutaneous fat in Werner syndrome.

Werner syndrome (WS) is a hereditary premature aging disorder characterized by visceral fat accumulation and subcutaneous lipoatrophy, resulting in severe insulin resistance. However, its underlying mechanism remains unclear. In this study, we show that senescence-associated inflammation and suppressed adipogenesis play a role in subcutaneous adipose tissue reduction and dysfunction in WS. Clinical data from four Japanese patients with WS revealed significant associations between the decrease of areas of subcutaneous fat and increased insulin resistance measured by the glucose clamp. Adipose-derived stem cells from the stromal vascular fraction derived from WS subcutaneous adipose tissues (WSVF) showed early replicative senescence and a significant increase in the expression of senescence-associated secretory phenotype (SASP) markers. Additionally, adipogenesis and insulin signaling were suppressed in WSVF, and the expression of adipogenesis suppressor genes and SASP-related genes was increased. Rapamycin, an inhibitor of the mammalian target of rapamycin (mTOR), alleviated premature cellular senescence, rescued the decrease in insulin signaling, and extended the lifespan of WS model of C. elegans. To the best of our knowledge, this study is the first to reveal the critical role of cellular senescence in subcutaneous lipoatrophy and severe insulin resistance in WS, highlighting the therapeutic potential of rapamycin for this disease.

Insulin Sensitivity Initially Worsens but Later Improves With Aging in Male C57BL/6N Mice.

Aging is believed to induce insulin resistance in humans. However, when and how insulin sensitivity changes with aging remains unclear in both humans and mice. In this study, groups of male C57BL/6N mice at 9-19 weeks (young), 34-67 weeks (mature adult), 84-85 weeks (presenile), and 107-121 weeks of age underwent hyperinsulinemic-euglycemic clamp studies with somatostatin infusion under awake and nonrestrained conditions. The glucose infusion rates for maintaining euglycemia were 18.4 ± 2.9, 5.9 ± 1.3, 20.3 ± 7.2, and 25.3 ± 4.4 mg/kg/min in young, mature adult, presenile, and aged mice, respectively. Thus, compared with young mice, mature adult mice exhibited the expected insulin resistance. In contrast, presenile and aged mice showed significantly higher insulin sensitivity than mature adult mice. These age-related changes were mainly observed in glucose uptake into adipose tissue and skeletal muscle (rates of glucose disappearance were 24.3 ± 2.0, 17.1 ± 1.0, 25.5 ± 5.2, and 31.8 ± 2.9 mg/kg/min in young, mature adult, presenile, and aged mice, respectively). Epididymal fat weight and hepatic triglyceride levels were higher in mature adult mice than those in young and aged mice. Our observations indicate that, in male C57BL/6N mice, insulin resistance appears at the mature adult stage of life but subsequently improves markedly. These alterations in insulin sensitivity are attributable to changes in visceral fat accumulations and age-related factors.

Effects of Sodium Glucose Co-Transporter 2 Inhibitors in Type 1 Diabetes Mellitus on Body Composition and Glucose Variabilities: Single-Arm, Exploratory Trial.

INTRODUCTION: Sodium glucose co-transporter 2 (SGLT2) inhibitors are widely used in the management of type 2 diabetes mellitus; they prevent cardiovascular events and reduce fat mass. However, little is known about the effects of SGLT2 inhibitors on type 1 diabetes mellitus as an adjuvant to insulin therapy. Therefore, we aimed to elucidate the effects of SGLT2 inhibitors on body composition of patients with type 1 diabetes mellitus and assess blood glucose variability. METHODS: A single-center, single-arm, prospective, interventional study was performed on Japanese patients with type 1 diabetes mellitus who were not administered SGLT2 inhibitors prior to this study. These patients were equipped with flash glucose monitoring (FGM) and administered ipragliflozin 50 mg daily. Body composition was evaluated using bioelectrical impedance analysis, and glycemic variabilities were assessed using FGM before and after SGLT2 inhibitor treatment. RESULTS: After 52 weeks of treatment, the total fat mass tended to be reduced (- 9.10% from baseline, P = 0.098). In addition, skeletal muscle mass also decreased (- 2.98% from baseline, P = 0.023). Although the basal insulin dose was reduced, SGLT2 inhibitors decreased HbA1c levels. FGM revealed that glycemic variabilities were also reduced, and time within the target glucose range increased (51.7% vs. 62.5%, P = 0.004). CONCLUSION: SGLT2 inhibitors have beneficial effects on glycemic variabilities and fat mass reductions in patients with type 1 diabetes mellitus. However, loss of skeletal muscle is a major concern; therefore, caution is required when using SGLT2 inhibitors in lean patients with type 1 diabetes mellitus. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trial Registry (UMIN000042407).

Assessing Patient Satisfaction Following Sodium Glucose Co-Transporter 2 Inhibitor Treatment for Type 1 Diabetes Mellitus: A Prospective Study in Japan.

INTRODUCTION: In Japan, several sodium glucose co-transporter 2 (SGLT2) inhibitors have been used for type 1 diabetes mellitus as an adjuvant therapy to insulin therapy; however, there are no clinical reports regarding the satisfaction of its use. Therefore, we conducted a survey among patients with type 1 diabetes undergoing treatment using an SGLT2 inhibitor. METHODS: This is a single-arm open-label prospective study including 24 patients with type 1 diabetes who were to be initiated on ipragliflozin treatment between March and August 2019. All participants provided written informed consent. They completed the Diabetes Treatment Satisfaction Questionnaire (DTSQ) for the survey and 3 months of observation after the administration of an SGLT2 inhibitor (50 mg of ipragliflozin), and changes from baseline diabetes treatment satisfaction were evaluated using modified DTSQ scores (five-step evaluation) and were analyzed. RESULTS: The average score for each question on DTSQ significantly increased [mean (standard deviation); 0.25 (0.25) vs 0.83 (0.77), P = 0.004]. Approximately 75% of the patients perceived an improvement in glycemic control over short periods of time. Finally, 54.2% of patients were highly satisfied and would recommend the SGLT2 inhibitor treatment [0.0 (0.0) vs. 0.92 (1.32), P < 0.001]. After the administration of ipragliflozin, reductions in body weight [24.0 (2.9) vs. 23.4 (2.9) kg/m2, P = 0.002], total insulin [39.1 (12.9) vs. 34.3 (12.5) units, P = 0.013], and glycated hemoglobin [7.77 (0.97) vs. 7.40 (0.86) %, P = 0.013] were observed, without any severe side effects. Improvements in glycemic variability indexes were observed through flash glucose monitoring. CONCLUSIONS: SGLT2 inhibitors may improve clinical treatment satisfaction by improving glycemic variability in patients with type 1 diabetes mellitus, while not inducing severe side effects with careful use. TRIAL REGISTRATION: This study is registered with the University Hospital Medical Information Network Clinical Trial Registry (UMIN000040487).