SGLT2 Inhibition Increases Fasting Glucagon but Does Not Restore the Counterregulatory Hormone Response to Hypoglycemia in Participants With Type 1 Diabetes

Effect of dapagliflozin on blood and breath ketones during supervised insulin withdrawal in adults with type 1 diabetes: A randomized crossover trial

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors increase ketoacidosis risk, limiting their use in type 1 diabetes. To better understand the pathophysiology of SGLT2 inhibitor-mediated ketoacidosis, we measured blood glucose, capillary blood and plasma β-hydroxybutyrate (BOHB) and breath acetone (BrACE) during supervised insulin withdrawal in adults with type 1 diabetes with and without dapagliflozin treatment.

MATERIALS AND METHODS

Twenty adults with type 1 diabetes underwent supervised insulin withdrawal twice in a randomized crossover design: during usual care and after treatment with dapagliflozin (10 mg daily for 2 weeks plus the test day). After insulin withdrawal, capillary blood glucose, BOHB and BrACE measurements were obtained at least hourly until stopping rules were met (>8 h elapsed, symptoms of ketosis, glucose >400 mg/dL, BOHB >4 mmol/L or participant request).

RESULTS

The peak BOHB and BrACE values achieved during supervised insulin withdrawal were both greater with dapagliflozin than with usual care. Throughout the insulin withdrawal study, dapagliflozin treatment was associated with significantly greater BOHB and BrACE concentrations. The proportions of participants reaching BOHB >1.5 mmol/L and >2.5 mmol/L during supervised insulin withdrawal were greater in the dapagliflozin arm. Blood glucose reached a lower peak in the dapagliflozin arm.

CONCLUSIONS

In adults with type 1 diabetes undergoing supervised insulin withdrawal, dapagliflozin treatment compared to usual care was associated with greater blood and breath ketone concentrations in the absence of significant hyperglycaemia.

Investigating the impact of intestinal glucagon-like peptide-1 on hypoglycemia in type 1 diabetes

Recent advances in understanding type 1 diabetes (T1D) highlight the complexity of managing hypoglycemia, a frequent and perilous complication of diabetes therapy. This letter delves into a novel study by Jin et al, which elucidates the role of intestinal glucagon-like peptide-1 (GLP-1) in the counterregulatory response to hypoglycemia in T1D models. The study employed immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay to track changes in GLP-1 and its receptor expression in diabetic mice subjected to recurrent hypoglycemic episodes. Findings indicate a significant increase in intestinal GLP-1 and GLP-1 receptor expression, correlating with diminished adrenal and glucagon responses, crucial for glucose stabilization during hypoglycemic events. This letter aims to explore the implications of these findings for future therapeutic strategies and the broader understanding of T1D management.

Combination SGLT2 Inhibitor and Glucagon Receptor Antagonist Therapy in Type 1 Diabetes: A Randomized Clinical Trial

OBJECTIVE

To examine the effects of insulin-adjunctive therapy with a sodium-glucose cotransporter 2 (SGLT2) inhibitor and a glucagon receptor antagonist (GRA) on glycemia, insulin use, and ketogenesis during insulinopenia in type 1 diabetes.

RESEARCH DESIGN AND METHODS

In a randomized, double-blind, placebo-controlled, crossover trial we assessed the effects of adjunctive SGLT2 inhibitor therapy (dapagliflozin 10 mg daily) alone and in combination with the GRA volagidemab (70 mg weekly) in 12 adults with type 1 diabetes. Continuous glucose monitoring, insulin dosing, and insulin withdrawal tests (IWT) for measurement of glucose and ketogenesis during insulinopenia were completed during insulin-only (Baseline), SGLT2 inhibitor, and combination (SGLT2 inhibitor + GRA) therapy periods.

RESULTS

Average glucose and percent time with glucose in range (70-180 mg/dL) improved with combination therapy versus Baseline and SGLT2 inhibitor (131 vs. 150 and 138 mg/dL [P < 0.001 and P = 0.01] and 86% vs. 70% and 78% [P < 0.001 and P = 0.03], respectively) without increased hypoglycemia. Total daily insulin use decreased with combination therapy versus Baseline and SGLT2 inhibitor (0.41 vs. 0.56 and 0.52 units/kg/day [P < 0.001 and P = 0.002]). Peak β-hydroxybutyrate levels during IWT were lower with combination therapy than with SGLT2 inhibitor (2.0 vs. 2.4 mmol/L; P = 0.048) and similar to levels reached during the Baseline testing period (2.1 mmol/L). Participants reported enhanced treatment acceptability and satisfaction with combination therapy.

CONCLUSIONS

Glucagon antagonism enhances the therapeutic effects of SGLT2 inhibition in type 1 diabetes. Combination therapy improves glycemic control, reduces insulin dosing, and suggests a strategy to unlock the benefits of SGLT2 inhibitors while mitigating the risk of diabetic ketoacidosis.

Glucagon secretion and its association with glycaemic control and ketogenesis during sodium-glucose cotransporter 2 inhibition by ipragliflozin in people with type 1 diabetes: Results from the multicentre, open-label, prospective study

AIM

Clinical trials showed the efficacy of sodium-glucose cotransporter 2 inhibitors for type 1 diabetes (T1D) by significant reductions in body weight and glycaemic variability, but elevated susceptibility to ketoacidosis via elevated glucagon secretion was a potential concern. The Suglat-AID evaluated glucagon responses and its associations with glycaemic control and ketogenesis before and after T1D treatment with the sodium-glucose cotransporter 2 inhibitor, ipragliflozin.

METHODS

Adults with T1D (n = 25) took 50-mg open-labelled ipragliflozin daily as adjunctive to insulin. Laboratory/clinical data including continuous glucose monitoring were collected until 12 weeks after the ipragliflozin initiation. The participants underwent a mixed-meal tolerance test (MMTT) twice [before (first MMTT) and 12 weeks after ipragliflozin treatment (second MMTT)] to evaluate responses of glucose, C-peptide, glucagon and β-hydroxybutyrate.

RESULTS

The area under the curve from fasting (0 min) to 120 min (AUC0-120min) of glucagon in second MMTT were significantly increased by 14% versus first MMTT. The fasting and postprandial β-hydroxybutyrate levels were significantly elevated in second MMTT versus first MMTT. The positive correlation between postprandial glucagon secretion and glucose excursions observed in first MMTT disappeared in second MMTT, but a negative correlation between fasting glucagon and time below range (glucose, <3.9 mmol/L) appeared in second MMTT. The percentage changes in glucagon levels (fasting and AUC0-120min) from baseline to 12 weeks were significantly correlated with those in β-hydroxybutyrate levels.

CONCLUSIONS

Ipragliflozin treatment for T1D increased postprandial glucagon secretion, which did not exacerbate postprandial hyperglycaemia but might protect against hypoglycaemia, leading to reduced glycaemic variability. The increased glucagon secretion might accelerate ketogenesis when adequate insulin is not supplied.

Sodium glucose cotransporter2 inhibitors for type 1 diabetes mellitus: A meta-analysis of randomized controlled trials

AIMS

Sodium glucose cotransporter2 (SGLT2) inhibitors are controversial in the treatment of type 1 diabetes mellitus (T1DM). This study is a systematic evaluation of the safety of SGLT2 inhibitors usage in T1DM.

METHODS

Comprehensive literature search in six databases from inception to September 2022. Randomized controlled trials (RCTs) of T1DM treated with SGLT2 inhibitor vs. placebo were included. Data were extracted from the literature that met the inclusion criteria. After quality evaluation by the Cochrane risk bias assessment tool, meta-analysis was performed using Revman 5.4 and Stata 17.1.

RESULTS

The study consisted of 16 RCTs with 7192 patients. The results indicated that SGLT2inhibitors reduce glycated hemoglobin (HbA1c, Mean difference (MD)- 0.29%, P < 0.05), fasting plasma glucose (FPG, MD-0.85 mmol/L, P < 0.05), mean amplitude of glucose excursions (MAGE, 15.75 mg/dL, P < 0.05), body weight (MD-3.49 kg, P < 0.05), and total insulin dosage (MD-7.14 IU/day, P < 0.05). Furthermore, cautious SGLT2 inhibitors did not induce the risk of hypoglycemia (RR1.00, P = 0.86), urinary tract infections (RR1.02, P = 0.085), and diarrhea (RR1.34, P = 0.523).

CONCLUSION

Based on this meta-analysis, SGLT22 inhibitors reduce insulin dosage without increasing the risk of hypoglycemia and diabetic ketoacidosis for type 1 diabetes mellitus in 1month.

Current and future therapies to treat impaired awareness of hypoglycemia

In order to achieve optimal glycemic control, intensive insulin regimes are needed for individuals with Type 1 Diabetes (T1D) and insulin-dependent Type 2 Diabetes (T2D). Unfortunately, intensive glycemic control often results in insulin-induced hypoglycemia. Moreover, recurrent episodes of hypoglycemia result in both the loss of the characteristic warning symptoms associated with hypoglycemia and an attenuated counterregulatory hormone responses. The blunting of warning symptoms is known as impaired awareness of hypoglycemia (IAH). Together, IAH and the loss of the hormonal response is termed hypoglycemia associated autonomic failure (HAAF). IAH is prevalent in up to 25% in people with T1D and up to 10% in people with T2D. IAH and HAAF increase the risk of severe hypoglycemia 6-fold and 25-fold, respectively. To reduce this risk for severe hypoglycemia, multiple different therapeutic approaches are being explored that could improve awareness of hypoglycemia. Current therapies to improve awareness of hypoglycemia include patient education and psychoeducation, the use of novel glycemic control technology, pancreas/islet transplantation, and drug therapy. This review examines both existing therapies and potential therapies that are in pre-clinical testing. Novel treatments that improve awareness of hypoglycemia, via improving the counterregulatory hormone responses or improving hypoglycemic symptom recognition, would also shed light on the possible neurological mechanisms that lead to the development of IAH. To reduce the risk of severe hypoglycemia in people with diabetes, elucidating the mechanism behind IAH, as well as developing targeted therapies is currently an unmet need for those that suffer from IAH.

Elevated circulating level of β-aminoisobutyric acid (BAIBA) in heart failure patients with type 2 diabetes receiving sodium-glucose cotransporter 2 inhibitors

AIMS

The mechanism by which a sodium-glucose cotransporter inhibitor (SGLT2i) induces favorable effects on diabetes and cardiovascular diseases including heart failure (HF) remains poorly understood. Metabolomics including amino acid profiling enables detection of alterations in whole body metabolism. The aim of this study was to determine whether plasma amino acid profiles are modulated by SGLT2i use in HF patients with type 2 diabetes mellitus (T2DM).

METHODS

We retrospectively examined 81 HF patients with T2DM (68 ± 11 years old; 78% male). Plasma amino acid concentrations in a fasting state after stabilization of HF were determined using ultraperformance liquid chromatography. To minimize potential selection bias in the retrospective analyses, the differences in baseline characteristics between patients receiving an SGLT2i and patients not receiving an SGLT2i were controlled by using an inverse probability of treatment weighting (IPTW)-adjusted analysis.

RESULTS

Of amino acids measurable in the present assay, plasma β-aminoisobutyric acid (BAIBA), an exercise-induced myokine-like molecule also known as 3-aminoisobutyric acid or 3-amino-2-methyproponic acid, was detected in 77% of all patients and the proportion of patients in whom plasma BAIBA was detected was significantly higher in patients receiving an SGLT2i than in patients not receiving an SGLT2i (93% vs. 67%, p = 0.01). Analyses in patients in whom plasma BAIBA was detected showed that plasma BAIBA concentration was significantly higher in patients receiving an SGLT2i than in patients not receiving an SGLT2i (6.76 ± 4.72 vs. 4.56 ± 2.93 nmol/ml, p = 0.03). In multivariate logistic regression analyses that were adjusted for age and sex, SGLT2i use was independently associated with BAIBA detection. The independent association between BAIBA and SGLT2i use remained after inclusion of body mass index, HF with reduced ejection fraction, ischemic etiology, renal function, NT-proBNP, albumin, hemoglobin, and HbA1c into the Cox proportional hazards model. When the differences in baseline characteristics between patients receiving an SGLT2i and patients not receiving an SGLT2i were controlled by using an IPTW-adjusted analysis, least squares mean of plasma BAIBA concentration was significantly higher in patients receiving an SGLT2i than in patients not receiving an SGLT2i.

CONCLUSION

SGLT2i use is closely associated with increased circulating BAIBA concentration in HF patients with T2DM.