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

Sodium-glucose co-transporter 2 inhibitors and Sarcopenia: A controversy that must be solved

Diabetes mellitus is a risk factor for muscle loss and sarcopenia. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) or "gliflozins" are one of the newest anti-hyperglycemic drugs. They reduce blood glucose levels by inhibiting renal glucose reabsorption in the early proximal convoluted tubule. Various randomized trials showed that SGLT2i have cardio-protective and reno-protective action. SGLT2i also affect body composition. They usually decrease body fat percentage, visceral and subcutaneous adipose tissue. However, regarding the muscle mass, there are conflicting findings some studies showing detrimental effects and others showed neutral or beneficial effects. This issue is extremely important not only because of the wide use of SGLT2i around globe; but also skeletal muscle mass consumes large amounts of calories during exercise and is an important determinant of resting metabolic rate and skeletal muscle loss hinders energy consumption leading to obesity. In this systematic review, we extensively reviewed the experimental and clinical studies regarding the impact of SGLT2i on muscle mass and related metabolic alterations. Importantly, studies are heterogeneous and there is unmet need to highlight the alterations in muscle during SGLT2i use.

SGLT2 Inhibitors in the Management of Type 1 Diabetes (T1D): An Update on Current Evidence and Recommendations

SGLT2i (sodium glucose transporter type 2 inhibitors) are pharmacological agents that act by inhibiting the SGLT2, by reducing the renal plasma glucose threshold and inducing glycosuria, resulting in a blood glucose lowering effect. In recent years, studies demonstrating some additional positive effects of SGLT2i also in the treatment of T1D have increased progressively. The SGLT2i dapagliflozin and sotagliflozin have been temporarily licensed for use by the European Medical Agency (EMA) as an adjunct to insulin therapy in adults with T1D with a body mass index of 27 kg/m2 or higher. However, in the meantime, the US Food and Drug Administration (FDA) Endocrinologic and Metabolic Drugs Advisory Committee was divided, citing concerns about the main side effects of SGLT2i, especially diabetic ketoacidosis (DKA). The aim of this manuscript was to conduct an update on current evidence and recommendations of the reported use of SGLT2i in the treatment of T1D in humans. Preclinical studies, clinical trial and real world data suggest benefits in glycaemia control and nefro-cardiovascular protection, even though several studies have documented an important increase in the risk of DKA, a serious and life-threatening adverse event of these agents. SGLT2i potentially addresses some of the unmet needs associated with T1D by improving glycaemic control with weight loss and without increasing hypoglycemia, by reducing glycaemic variability. However, due to side effects, EMA recommendation for SGLT2 use on T1D was withdrawn. Further studies will be needed to determine the safety of this therapy in T1D and to define the type of patient who can benefit most from these medications.

Effects of the SGLT2 Inhibition on Cardiac Remodeling in Streptozotocin-Induced Diabetic Rats, a Model of Type 1 Diabetes Mellitus

Clinical trials have shown that sodium glucose co-transporter 2 (SGLT2) inhibitors improve clinical outcomes in diabetes mellitus (DM) patients. As most studies were performed in Type 2 DM, the cardiovascular effects of SGLT2 inhibition still require clarification in Type 1 DM. We analyzed the effects of SGLT2 inhibitor dapagliflozin on cardiac remodeling in rats with streptozotocin-induced diabetes, an experimental model of Type 1 DM. Methods: Male Wistar rats were assigned into four groups: control (C, n = 14); control treated with dapagliflozin (C + DAPA, n = 14); diabetes (DM, n = 20); and diabetes treated with dapagliflozin (DM + DAPA, n = 20) for 8 weeks. Dapagliflozin dosage was 5 mg/kg/day. Statistical analyses: ANOVA and Tukey or Kruskal−Wallis and Dunn. Results: DM + DAPA presented decreased blood pressure and glycemia and increased body weight compared to DM (C 507 ± 52; C + DAPA 474 ± 50; DM 381 ± 52 *; DM + DAPA 430 ± 48 # g; * p < 0.05 vs. C; # p < 0.05 vs. C + DAPA and DM + DAPA). DM echocardiogram presented left ventricular and left atrium dilation with impaired systolic and diastolic function. Cardiac changes were attenuated by dapagliflozin. Myocardial hydroxyproline concentration and interstitial collagen fraction did not differ between groups. The expression of Type III collagen was lower in DM and DM + DAPA than their controls. Type I collagen expression and Type I-to-III collagen ratio were lower in DM + DAPA than C + DAPA. DM + DAPA had lower lipid hydroperoxide concentration (C 275 ± 42; C + DAPA 299 ± 50; DM 385 ± 54 *; DM + DAPA 304 ± 40 # nmol/g tissue; * p < 0.05 vs. C; # p < 0.05 vs. DM) and higher superoxide dismutase and glutathione peroxidase activity than DM. Advanced glycation end products did not differ between groups. Conclusion: Dapagliflozin is safe, increases body weight, decreases glycemia and oxidative stress, and attenuates cardiac remodeling in an experimental rat model of Type 1 diabetes mellitus.

Glycaemic variabilities: Key questions in pursuit of clarity

After years of intensive investigation, the definition of glycaemic variability remains unclear and the term variability in glucose homoeostasis might be more appropriate covering both short and long-term glycaemic variability. For the latter, we remain in the search of an accurate definition and related targets. Recent work leads us to consider that the within-subject variability of HbA1c calculated from consecutive determinations of HbA1c at regular time-intervals could be the most relevant index for assessing the long-term variability with a threshold value of 5% (%CV = SD of HbA1c/mean HbA1c) to separate stability from lability of HbA1c. Presently, no one can deny that short- and long-term glucose variability should be maintained within their lower ranges to limit the incidence of hypoglycaemia. Usually, therapeutic strategies aimed at reducing post-meal glucose excursions, i.e. the major contributor to daily glucose fluctuations, exert a beneficial effect on the short-term glucose variability. This explains the effectiveness of adjunct therapies with either GLP- receptor agonists or SGLT inhibitors in type 2 diabetes. In type 1 diabetes, the application of a CGM device alone reduces the short-term glycaemic variability. In contrast, sophisticated insulin delivery does not necessarily lead to such reductions despite marked downward shifts of 24-hour glycaemic profiles. Such contrasting observations raise the question as to whether the prolonged wear of CGM devices is or not the major causative factor for improvement in glucose variability among intensively insulin-treated persons with type 1 diabetes.

Sodium/glucose cotransporter 2 inhibitors for the treatment of type 1 diabetes: what are the latest developments?

Despite the improvements in insulin therapy, many patients with type 1 diabetes mellitus (T1DM) do not achieve glycemic targets. Hypoglycemia and weight gain are important barriers in reaching these targets. Sodium/glucose cotransporter 2 (SGLT2) inhibitors lack these side effects and have an insulin-independent mechanism of action. Therefore, they might be useful in patients with T1DM. The authors discuss the safety and efficacy of SGLT2 inhibitors in T1DM. Several randomized controlled trials have evaluated dapagliflozin, sotagliflozin and empagliflozin in this population whereas fewer data are available for other members of this class. In these studies, SGLT2 inhibitors reduced HbA_1c levels and body weight without a greater risk of hypoglycemia. However, a higher incidence of diabetic ketoacidosis (DKA) was observed in patients treated with these agents. SGLT2 inhibitors improve glycemic control in patients with T1DM but this effect is modest. Even though weight loss and the neutral effect on the incidence of hypoglycemia are advantages of these agents, the increased risk of DKA is a cause of concern. Overall, SGLT2 inhibitors should be used with caution and only in carefully selected patients with T1DM who are motivated, adherent to treatment, well-trained in recognizing DKA and are closely followed-up.