Dapagliflozin, a sodium glucose cotransporter 2 inhibitors, protects cardiovascular function in type-2 diabetic murine model

Effects of Dapagliflozin on Myocardial Gene Expression in BTBR Mice with Type 2 Diabetes

BACKGROUND

Dapagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, is approved for the treatment of type 2 diabetes, heart failure, and chronic kidney disease. DAPA-HF and DELIVER trial results demonstrate that the cardiovascular protective effect of dapagliflozin extends to non-diabetic patients. Hence, the mechanism-of-action may extend beyond glucose-lowering and is not completely elucidated. We have previously shown that dapagliflozin reduces cardiac hypertrophy, inflammation, fibrosis, and apoptosis and increases ejection fraction in BTBR mice with type 2 diabetes.

METHODS

We conducted a follow-up RNA-sequencing study on the heart tissue of these animals and performed differential expression and Ingenuity Pathway analysis. Selected markers were confirmed by RT-PCR and Western blot.

RESULTS

SGLT2 had negligible expression in heart tissue. Dapagliflozin improved cardiac metabolism by decreasing glycolysis and pyruvate utilization enzymes, induced antioxidant enzymes, and decreased expression of hypoxia markers. Expression of inflammation, apoptosis, and hypertrophy pathways was decreased. These observations corresponded to the effects of dapagliflozin in the clinical trials.

Cardioprotection of Canagliflozin, Dapagliflozin, and Empagliflozin: Lessons from preclinical studies

Clinical and preclinical studies have elucidated the favorable effects of Inhibitors of Sodium-Glucose Cotransporter-2 (iSGLT2) in patients and animal models with type 2 diabetes. Notably, these inhibitors have shown significant benefits in reducing hospitalizations and mortality among patients with heart failure. However, despite their incorporation into clinical practice for indications beyond diabetes, the decision-making process regarding their use often lacks a systematic approach. The selection of iSGLT2 remains arbitrary, with only a limited number of studies simultaneously exploring the different classes of them. Currently, no unique guideline establishes their application in both clinical and basic research. This review delves into the prevalent use of iSGLT2 in animal models previously subjected to induced cardiac stress. We have compiled key findings related to cardioprotection across various animal models, encompassing diverse dosages and routes of administration. Beyond their established role in diabetes management, iSGLT2 has demonstrated utility as agents for safeguarding heart health and cardioprotection can be class-dependent among the iSGLT2. These findings may serve as valuable references for other researchers. Preclinical studies play a pivotal role in ensuring the safety of novel compounds or treatments for potential human use. By assessing side effects, toxicity, and optimal dosages, these studies offer a robust foundation for informed decisions, identifying interventions with the highest likelihood of success and minimal risk to patients. The insights gleaned from preclinical studies, which play a crucial role in highlighting areas of knowledge deficiency, can guide the exploration of novel mechanisms and strategies involving iSGLT2.

Dapagliflozin Ameliorates Neural Damage in the Heart and Kidney of Diabetic Mice

(1) Background: Measures for the control of diabetes mellitus (DM) and, especially, for the control of its complications represent a main objective of the research carried out on this disease, since both mortality and morbidity relating to DM represent real problems for the health system worldwide. The aim of our study was to evaluate nervous tissue from the heart and kidneys of mice with diabetes induced by streptozotocin (STZ) in the presence or absence of dapagliflozin (DAPA) treatment. (2) Methods: For this purpose, we used 24 C 57Bl/6 male mice, aged between 8 and 10 weeks. The mice were divided into three groups: sham (DM-), control (DM+), and treated (DM+). Diabetes mellitus was induced by injecting a single intraperitoneal dose of STZ. The duration of diabetes in the mice included in our study was 12 weeks after STZ administration; then, the heart and kidneys were sampled, and nervous tissue (using the primary antibody PGP 9.5) from the whole heart, from the atrioventricular node, and from the kidneys was analyzed. (3) Results: The density of nerve tissue registered a significant decrease in animals from the control group (DM+), to a value of 0.0122 ± 0.005 mm2 nerve tissue/mm2 cardiac tissue, compared with the sham group (DM-), wherein the value was 0.022 ± 0.006 mm2 nervous tissue/mm2 cardiac tissue (p = 0.004). Treatment with dapagliflozin reduced the nerve tissue damage in the treated (DM+DAPA) group of animals, resulting in a nerve tissue density of 0.019 ± 0.004 mm2 nerve tissue/mm2 cardiac tissue; a statistically significant difference was noted between the control (DM+) and treated (DM+DAPA) groups (p = 0.046). The same trends of improvement in nerve fiber damage in DM after treatment with DAPA were observed both in the atrioventricular node and in the kidneys. (4) Conclusions. These data suggest that dapagliflozin, when used in streptozotocin-induced diabetes in mice, reduces the alteration of the nervous system in the kidneys and in the heart, thus highlighting better preservation of cardiac and renal homeostasis, independent of any reduction in the effects of hyperglycemia produced in this disease.

Experimental Models to Study Diabetes Mellitus and Its Complications: Limitations and New Opportunities

Preclinical biomedical models are a fundamental tool to improve the knowledge and management of diseases, particularly in diabetes mellitus (DM) since, currently, the pathophysiological and molecular mechanisms involved in its development are not fully clarified, and there is no treatment to cure DM. This review will focus on the features, advantages and limitations of some of the most used DM models in rats, such as the spontaneous models: Bio-Breeding Diabetes-Prone (BB-DP) and LEW.1AR1-iddm, as representative models of type 1 DM (DM-1); the Zucker diabetic fatty (ZDF) and Goto-kakizaki (GK) rats, as representative models of type 2 DM (DM-2); and other models induced by surgical, dietary and pharmacological-alloxan and streptozotocin-procedures. Given the variety of DM models in rats, as well as the non-uniformity in the protocols and the absence of all the manifestation of the long-term multifactorial complications of DM in humans, the researchers must choose the one that best suits the final objectives of the study. These circumstances, added to the fact that most of the experimental research in the literature is focused on the study of the early phase of DM, makes it necessary to develop long-term studies closer to DM in humans. In this review, a recently published rat DM model induced by streptozotocin injection with chronic exogenous administration of insulin to reduce hyperglycaemia has also been included in an attempt to mimic the chronic phase of DM in humans.

SGLT2 inhibition effect on salt-induced hypertension, RAAS, and Na+ transport in Dahl SS rats

Na+-glucose cotransporter-2 (SGLT2) inhibitors are the new mainstay of treatment for diabetes mellitus and cardiovascular diseases. Despite the remarkable benefits, the molecular mechanisms mediating the effects of SGLT2 inhibitors on water and electrolyte balance are incompletely understood. The goal of this study was to determine whether SGLT2 inhibition alters blood pressure and kidney function via affecting the renin-angiotensin-aldosterone system (RAAS) and Na+ channels/transporters along the nephron in Dahl salt-sensitive rats, a model of salt-induced hypertension. Administration of dapagliflozin (Dapa) at 2 mg/kg/day via drinking water for 3 wk blunted the development of salt-induced hypertension as evidenced by lower blood pressure and a left shift of the pressure natriuresis curve. Urinary flow rate, glucose excretion, and Na+- and Cl--to-creatinine ratios increased in Dapa-treated compared with vehicle-treated rats. To define the contribution of the RAAS, we measured various hormones. Despite apparent effects on Na+- and Cl--to-creatinine ratios, Dapa treatment did not affect RAAS metabolites. Subsequently, we assessed the effects of Dapa on renal Na+ channels and transporters using RT-PCR, Western blot analysis, and patch clamp. Neither mRNA nor protein expression levels of renal transporters (SGLT2, Na+/H+ exchanger isoform 3, Na+-K+-2Cl- cotransporter 2, Na+-Cl- cotransporter, and α-, β-, and γ-epithelial Na+ channel subunits) changed significantly between groups. Furthermore, electrophysiological experiments did not reveal any difference in Dapa treatment on the conductance and activity of epithelial Na+ channels. Our data suggest that SGLT2 inhibition in a nondiabetic model of salt-sensitive hypertension blunts the development of salt-induced hypertension by causing glucosuria and natriuresis without changes in the RAAS or the expression or activity of the main Na+ channels and transporters.NEW & NOTEWORTHY The present study indicates that Na+-glucose cotransporter-2 (SGLT2) inhibition in a nondiabetic model of salt-sensitive hypertension blunts the development and magnitude of salt-induced hypertension. Chronic inhibition of SGLT2 increases glucose and Na+ excretion without secondary effects on the expression and function of other Na+ transporters and channels along the nephron and hormone levels in the renin-angiotensin-aldosterone system. These data provide novel insights into the effects of SGLT2 inhibitors and their potential use in hypertension.

Evaluation of Plaque Burden and Lipid Content in Atherosclerotic Plaques

Atherosclerosis is a chronic inflammatory disease characterized by the formation of lipid-rich, fibrous plaques within the arterial wall of medium and large arteries. Plaques prone to rupture are typically rich in lipids and pro-inflammatory markers. Cells within the plaque can take up lipids via different mechanisms leading to the formation and accumulation of lipid-rich foam cells, a key hallmark of the disease. Evaluation of plaque burden and lipid content is hence important to determine disease progression and severity. This chapter describes the most commonly used staining methods that enable visualization and analysis of mouse atherosclerotic plaques. These methods include en face preparation of mouse aorta, and staining sections of arteries using hematoxylin and eosin, Oil Red O, and Masson's Trichrome.

A Novel Role of Dapagliflozin in Mitigation of Acetic Acid-Induced Ulcerative Colitis by Modulation of Monocyte Chemoattractant Protein 1 (MCP-1)/Nuclear Factor-Kappa B (NF-κB)/Interleukin-18 (IL-18)

Colon illnesses, particularly ulcerative colitis, are considered a major cause of death in both men and women around the world. The present study investigated the underlying molecular mechanisms for the potential anti-inflammatory effect of Dapagliflozin (DAPA) against ulcerative colitis (UC) induced by intracolonic instillation of 3% v/v acetic acid (AA). DAPA was administered to rats (1 mg/kg, orally) for two weeks during the treatment regimen. Interestingly, compared to the normal group, a marked increase in the index of colon/body weight, colon weight/colon length ratio, serum lactate dehydrogenase (LDH), and C-reactive protein (CRP), besides decrease in the serum total antioxidant capacity (TAC), were reported in the AA control group (p ˂ 0.05). Elevation in colon monocyte chemoattractant protein (MCP1), Interleukin 18 (IL-18), and inflammasome contents were also reported in the AA control group in comparison with the normal group. In addition, colon-specimen immunohistochemical staining revealed increased expression of nuclear factor-kappa B (NF-κB) and Caspase-3 with histopathological changes. Moreover, DAPA significantly (p ˂ 0.05) reduced the colon/body weight index, colon weight/colon length ratio, clinical evaluation, and macroscopic scoring of UC, and preserved the histopathological architecture of tissues. The inflammatory biomarkers, including colon MCP1, IL-18, inflammasome, Caspase-3, and NF-κB, were suppressed following DAPA treatment and oxidants/antioxidants hemostasis was also restored. Collectively, the present data demonstrate that DAPA represents an attractive approach to ameliorating ulcerative colitis through inhibiting MCP1/NF-κB/IL-18 pathways, thus preserving colon function. Antioxidant, anti-inflammatory, and anti-apoptotic properties of DAPA are implicated in its observed therapeutic benefits.

Effects of a 12-Month Treatment with Glucagon-like Peptide-1 Receptor Agonists, Sodium-Glucose Cotransporter-2 Inhibitors, and Their Combination on Oxidant and Antioxidant Biomarkers in Patients with Type 2 Diabetes

Imbalance between oxidative stress burden and antioxidant capacity is implicated in the course of atherosclerosis among type 2 diabetic patients. We addressed the effects of insulin, glucagon-like peptide-1 receptor agonists (GLP1-RA), sodium-glucose cotransporter-2 inhibitors (SGLT-2i), and their combination on levels of oxidant and antioxidant biomarkers. We recruited a total of 160 type 2 diabetics, who received insulin (n = 40), liraglutide (n = 40), empagliflozin (n = 40), or their combination (GLP-1RA+SGLT-2i) (n = 40). We measured at baseline, at 4 and at 12 months of treatment: (a) Thiobarbituric Acid Reactive Substances (TBARS), (b) Malondialdehyde (MDA), (c) Reducing Power (RP), (d) 2,2¢-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) radical (ABTS) and (e) Total Antioxidant Capacity TAC). Dual treatment resulted in significant improvement of TBARS, MDA, and ABTS at four months compared with the other groups (p < 0.05 for all comparisons). At twelve months, all participants improved TBARS, MDA, and ABTS (p < 0.05). At 12 months, GLP1-RA and GLP-1RA+SGLT2-i provided a greater reduction of TBARS (−8.76% and −9.83%) compared with insulin or SGLT2i (−0.5% and 3.22%), (p < 0.05). GLP1-RA and GLP-1RA+SGLT-2i showed a greater reduction of MDA (−30.15% and −31.44%) compared with insulin or SGLT2i (4.72% and −3.74%), (p < 0.05). SGLT2i and GLP-1RA+SGLT2-i showed increase of ABTS (12.87% and 14.13%) compared with insulin or GLP1-RA (2.44% and −3.44%), (p < 0.05). Only combined treatment resulted in increase of TAC compared with the other groups after 12 months of treatment (p < 0.05).12-month treatment with GLP1-RA and SGLT2i resulted in reduction of biomarkers responsible for oxidative modifications and increase of antioxidant biomarker, respectively. The combination treatment was superior and additive to each separate agent and also the beneficial effects appeared earlier.