Association of increased hepatic insulin clearance and change in serum triglycerides or β-hydroxybutyrate concentration via the sodium/glucose-cotransporter 2 inhibitor tofogliflozin

Body fluid regulation via chronic inhibition of sodium-glucose cotransporter-2 in patients with heart failure: a post hoc analysis of the CANDLE trial

BACKGROUND

In patients with chronic heart failure (CHF) and type 2 diabetes (T2D), sodium-glucose cotransporter-2 (SGLT2) inhibition improves cardiorenal outcomes, but details of the effects on distinct subsets of body fluid volume remain incomplete.

METHODS

This was a post hoc analysis of patients with CHF and T2D in the CANDLE trial (UMIN000017669), an investigator-initiated, multi-center, randomized open-label trial that compared the effect of canagliflozin (100 mg, n = 113) with glimepiride (starting dose: 0.5 mg, n = 120) on changes in N-terminal pro-brain natriuretic peptide. The estimated plasma volume (ePV, calculated with the Straus formula) and estimated extracellular volume (eEV, determined by the body surface area) were compared between treatment groups at weeks 4, 12, and 24.

RESULTS

Among 233 patients analyzed, 166 (71.2%) had an ejection fraction (EF) > 50%. Reductions in ePV and eEV were observed only in the canagliflozin group until week 12 (change from baseline at week 12, ePV; - 7.63%; 95% confidence interval [CI], - 10.71 to - 4.55%, p < 0.001, eEV; - 123.15 mL; 95% CI, - 190.38 to - 55.92 mL, p < 0.001). While ePV stopped falling after week 12, eEV continued to fall until week 24 ([change from baseline at week 24] - [change from baseline at week 12], ePV; 1.01%; 95%CI, - 2.30-4.32%, p = 0.549, eEV; - 125.15 mL; 95% CI, - 184.35 to - 65.95 mL, p < 0.001).

CONCLUSIONS

Maintenance of a modest reduction in ePV and continuous removal of eEV via chronic SGLT2 inhibition suggests that favorable body fluid regulation contributes to the cardiorenal benefits of SGLT2 inhibitors in patients with CHF, irrespective of EF.

TRIAL REGISTRATION

UMIN000017669.

The sodium-glucose cotransporter 2 inhibitor ipragliflozin improves liver function and insulin resistance in Japanese patients with type 2 diabetes

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment is a therapeutic approach for type 2 diabetes mellitus (T2DM). Some reports have shown that SGLT2i treatment improves insulin resistance; however, few studies have evaluated insulin resistance by the glucose clamp method. Hepatic insulin clearance (HIC) is a new pathophysiological mechanism of T2DM. The effect of SGLT2i treatment on hepatic insulin clearance and insulin resistance is not well known. We investigated the effect of SGLT2i treatment on insulin resistance, insulin secretion, incretin levels, body composition, and hepatic insulin clearance. We conducted a meal tolerance test (MTT) and a hyperinsulinemic-euglycemic clamp test in 9 T2DM patients. Ipragliflozin (50 mg/day) was administered, and the MTT and clamp test were performed after 4 months. We calculated HIC as the postprandial C-peptide AUC-to-insulin AUC ratio. We also measured GLP-1, GIP, and glucagon levels during the MTT. Body weight and HbA1c were decreased, although not significantly, after 4 months of treatment. Postprandial glucose, fasting insulin and postprandial insulin were significantly decreased. Insulin resistance with the glucose clamp was not changed, but the HOMA-IR and insulin sensitivity indices were significantly improved. Incretin and glucagon levels were not changed. Hepatic insulin clearance was significantly increased, but whole-body insulin clearance was not changed. The FIB-4 index and fatty liver index were significantly reduced. The HOMA-beta and insulinogenic indices were not changed, but the C-peptide index was significantly increased. Although the number of patients was small, these results suggested that SGLT2i treatment improved liver function, decreased hepatic insulin resistance, and increased hepatic insulin clearance, despite the small weight reduction.

Efficacy of canagliflozin versus metformin in women with polycystic ovary syndrome: A randomized, open-label, noninferiority trial

OBJECTIVES

To determine the safety and efficacy of canagliflozin in comparison to metformin in polycystic ovary syndrome (PCOS) patients with insulin resistance (IR).

METHODS

A single-centre, prospective, randomized open-label (ratio 1:1) noninferiority trial was conducted at the Department of Endocrinology, Shanghai Tenth People's Hospital, between July 2019 and April 2021. Women aged 18 to 45 years with PCOS and IR were enrolled and randomly assigned to either 100 mg (n = 33) canagliflozin daily or 1500 to 2000 mg metformin daily (n = 35) for 12 weeks. The primary outcome was changes in homeostatic model assessment (HOMA)-IR after 12 weeks of treatment. The secondary outcomes included changes in anthropometric measurements, menstrual frequency, sex hormone levels, metabolic variables and body fat distribution.

RESULTS

For lowering of HOMA-IR after 12 weeks of treatment, canagliflozin was found to be noninferior to metformin (least-squares mean difference -0.81% [95% confidence interval -2.13 to 0.51]). Both canagliflozin and metformin significantly improved menstrual pattern, reduced body weight and total fat mass, and decreased triglyceride levels. Compared with metformin, canagliflozin had significant advantages in reducing uric acid and dehydroepiandrosterone sulphate levels. Pruritus vulvae (9.09%) and gastrointestinal reaction (55.55%) were the main adverse events in the metformin group and canagliflozin group, respectively.

CONCLUSION

This study demonstrates that canagliflozin was not inferior to metformin in PCOS patients with IR, which suggests that sodium-glucose cotransporter-2 inhibitors should be considered as effective drugs in the treatment of PCOS patients with IR.

Short-Term SGLT2 Inhibitor Administration Does Not Alter Systemic Insulin Clearance in Type 2 Diabetes

Background: Decreased insulin clearance could be a relatively upstream abnormality in obesity, metabolic syndrome, and nonalcoholic fatty liver disease. Previous studies have shown that sodium-glucose cotransporter 2 inhibitor (SGLT2i) increases insulin–C-peptide ratio, a marker of insulin clearance, and improves metabolic parameters. We evaluated the effects of the SGLT2i tofogliflozin on metabolic clearance rate of insulin (MCRI) with a hyperinsulinemic euglycemic clamp study, the gold standard for measuring systemic insulin clearance. Methods: Study participants were 12 Japanese men with type 2 diabetes. We evaluated MCRI and tissue-specific insulin sensitivity with a hyperinsulinemic euglycemic clamp (insulin infusion rate, 40 mU/m²·min) before and immediately after a single dose (n = 12) and 8 weeks (n = 9) of tofogliflozin. We also measured ectopic fat in muscle and liver and the abdominal fat area using ¹H-magnetic resonance spectroscopy and magnetic resonance imaging, respectively, before and after 8 weeks of tofogliflozin. Results: MCRI did not change after a single dose of tofogliflozin (594.7 ± 67.7 mL/min·m² and 608.3 ± 90.9 mL/min·m², p = 0.61) or after 8 weeks (582.5 ± 67.3 mL/min·m² and 602.3 ± 67.0 mL/min·m², p = 0.41). The 8-week treatment significantly improved glycated hemoglobin and decreased body weight (1.7%) and the subcutaneous fat area (6.4%), whereas insulin sensitivity and ectopic fat in muscle and liver did not change significantly. Conclusions: MCRI did not change after a single dose or 8 weeks of tofogliflozin. Increased MCRI does not precede a decrease in body fat or improved glycemic control.

Transcriptomic Analysis Reveals the Protective Effects of Empagliflozin on Lipid Metabolism in Nonalcoholic Fatty Liver Disease

Empagliflozin is a novel type of sodium-glucose cotransporter two inhibitor with diverse beneficial effects in the treatment of nonalcoholic fatty liver disease (NAFLD). Although empagliflozin impacts NAFLD by regulating lipid metabolism, the underlying mechanism has not been fully elucidated. In this study, we investigated transcriptional regulation pathways affected by empagliflozin in a mouse model of NAFLD. In this study, NAFLD was established in male C57BL/6J mice by administration of a high-fat diet; it was then treated with empagliflozin and whole transcriptome analysis was conducted. Gene expression levels detected by transcriptome analysis were then verified by quantitative real-time polymerase chain reaction, protein levels detected by Western Blot. Differential expression genes screened from RNA-Seq data were enriched in lipid metabolism and synthesis. The Gene Set Enrichment Analysis (GSEA) results showed decreased lipid synthesis and improved lipid metabolism. Empagliflozin improved NAFLD through enhanced triglyceride transfer, triglyceride lipolysis and microsomal mitochondrial β-oxidation. This study provides new insights concerning the mechanisms by which sodium-glucose cotransporter two inhibitors impact NAFLD, particularly in terms of liver lipid metabolism. The lipid metabolism-related genes identified in this experiment provide robust evidence for further analyses of the mechanism by which empagliflozin impacts NAFLD.

Beta-Hydroxybutyrate, Friend or Foe for Stressed Hearts

One of the characteristics of the failing human heart is a significant alteration in its energy metabolism. Recently, a ketone body, β-hydroxybutyrate (β-OHB) has been implicated in the failing heart’s energy metabolism as an alternative “fuel source.” Utilization of β-OHB in the failing heart increases, and this serves as a “fuel switch” that has been demonstrated to become an adaptive response to stress during the heart failure progression in both diabetic and non-diabetic patients. In addition to serving as an alternative “fuel,” β-OHB represents a signaling molecule that acts as an endogenous histone deacetylase (HDAC) inhibitor. It can increase histone acetylation or lysine acetylation of other signaling molecules. β-OHB has been shown to decrease the production of reactive oxygen species and activate autophagy. Moreover, β-OHB works as an NLR family pyrin domain-containing protein 3 (Nlrp3) inflammasome inhibitor and reduces Nlrp3-mediated inflammatory responses. It has also been reported that β-OHB plays a role in transcriptional or post-translational regulations of various genes’ expression. Increasing β-OHB levels prior to ischemia/reperfusion injury results in a reduced infarct size in rodents, likely due to the signaling function of β-OHB in addition to its role in providing energy. Sodium-glucose co-transporter-2 (SGLT2) inhibitors have been shown to exert strong beneficial effects on the cardiovascular system. They are also capable of increasing the production of β-OHB, which may partially explain their clinical efficacy. Despite all of the beneficial effects of β-OHB, some studies have shown detrimental effects of long-term exposure to β-OHB. Furthermore, not all means of increasing β-OHB levels in the heart are equally effective in treating heart failure. The best timing and therapeutic strategies for the delivery of β-OHB to treat heart disease are unknown and yet to be determined. In this review, we focus on the crucial role of ketone bodies, particularly β-OHB, as both an energy source and a signaling molecule in the stressed heart and the overall therapeutic potential of this compound for cardiovascular diseases.

Consequences on islet and incretin hormone responses to dinner by omission of lunch in healthy men

BACKGROUND

Omission of breakfast results in higher glucose and lower insulin and incretin hormone levels after both lunch and dinner. Whether omission of lunch has a similar impact on the following meal is not known.

AIM

This study therefore explored whether omission of lunch ingestion affects glucose, islet and incretin hormones after dinner ingestion in healthy subjects.

MATERIALS & METHODS

Twelve male volunteers (mean age 22 years, BMI 22.5 kg/m2) underwent two test days in random order with standard breakfast and dinner on both days with provision or omission of standard lunch in between.

RESULTS

The results showed that throughout the 300 minutes study period, glucose, insulin, glucagon and GIP levels after dinner ingestion did not differ between the two tests. In contrast, C-peptide, and GLP-1 levels were 26%-35% higher at later time points after dinner ingestion when lunch had been omitted (P < .05).

CONCLUSION

We conclude that omission of lunch increases GLP-1 and insulin secretion and possibly also insulin clearance resulting in unchanged glucose and insulin levels after dinner ingestion.

Association of increased hepatic insulin clearance and change in serum triglycerides or β-hydroxybutyrate concentration via the sodium/glucose-cotransporter 2 inhibitor tofogliflozin

AIMS

Obesity and hepatic fat accumulation diminish hepatic insulin clearance, which can cause hyperinsulinaemia. Sodium/glucose-cotransporter 2 inhibitors (SGLT2-is) improve insulin resistance and hyperinsulinaemia by weight loss via increased urinary glucose excretion in type 2 diabetes. However, there are few reports of the influence of SGLT2-is on hepatic insulin clearance. We examined the impact of an SGLT2-i on hepatic insulin clearance and explored the clinical influence associated with changes in hepatic insulin clearance via an SGLT2-i and the mechanism of the effects of SGLT2-i.

MATERIALS AND METHODS

Data were analysed from 419 patients with type 2 diabetes controlled by diet and exercise. Patients received a placebo or the SGLT2-i tofogliflozin (TOFO) (placebo: n = 56; TOFO: n = 363) orally once daily for ≥24 weeks. Hepatic insulin clearance was calculated from the ratio of areas under the curve (AUC) of C-peptide and insulin levels derived from oral meal tolerance test data (C-peptide AUC_{0-120 min} /insulin AUC_{0-120 min} : HIC_CIR ). The correlation of HIC_CIR via the SGLT2-i with other clinical variables was analysed using multivariate analysis.

RESULTS

HIC_CIR was significantly increased via TOFO at week 24. Furthermore, with TOFO insulin and triglyceride (TG) levels were significantly reduced (P < 0.001) and β-hydroxybutyrate (BHB) was significantly elevated (P < 0.001). Changes in HIC_CIR were significantly correlated with changes in TG and BHB via TOFO.

CONCLUSIONS

Increased HIC_CIR was significantly associated with reduced TG via TOFO and contributed to the greater increase in BHB compared with placebo in addition to the correction of hyperinsulinaemia.