Dapagliflozin has No Protective Effect on Experimental Pulmonary Arterial Hypertension and Pulmonary Trunk Banding Rat Models

Effects of empagliflozin on right ventricular adaptation to pressure overload

Background

Right ventricular (RV) failure is the prime cause of death in patients with pulmonary arterial hypertension. Novel treatment strategies that protect the RV are needed. Empagliflozin, a sodium-glucose co-transporter-2 inhibitor, shows cardioprotective effects on the left ventricle in clinical and preclinical studies, but its direct effects on RV remain elusive. We investigated the effects of empagliflozin on RV dysfunction induced by pulmonary trunk banding (PTB).

Methods

Male Wistar rats (116 ± 10 g) were randomized to PTB or sham surgery. One week after surgery, PTB animals received empagliflozin mixed into the chow (300 mg empagliflozin/kg chow; PTB-empa, n = 10) or standard chow (PTB-control, n = 10). Sham rats (Sham, n = 6) received standard chow. After five weeks, RV function was evaluated by echocardiography, cardiac MRI, and invasive pressure-volume measurements.

Results

PTB caused RV failure evident by decreased cardiac output compared with sham. PTB-empa rats had a 49% increase in water intake compared with PTB-control yet no differences in hematocrit or blood glucose. Treatment with empagliflozin decreased RV end-systolic pressures without any changes in RV cardiac output or ventricular-arterial coupling (Ees/Ea). The decrease in RV end-systolic pressure was complemented by a slight reduction in RV cross sectional area as a sign of reduced hypertrophy. Load-independent measures of RV systolic and diastolic function were not affected in PTB-empa rats compared with PTB-control.

Conclusion

Empagliflozin treatment reduced RV end-systolic pressure in RV failure induced by pressure overload. Further studies are needed to elucidate whether this simply relates to a diuretic effect and/or additional independent beneficial RV effects.

Therapeutic Approaches in Pulmonary Arterial Hypertension with Beneficial Effects on Right Ventricular Function-Preclinical Studies

Pulmonary hypertension (PH) is a progressive condition that affects the pulmonary vessels, but its main prognostic factor is the right ventricle (RV) function. Many mice/rat models are used for research in PAH, but results fail to translate to clinical trials. This study reviews studies that test interventions on pulmonary artery banding (PAB), a model of isolated RV disfunction, and PH models. Multiple tested drugs both improved pulmonary vascular hemodynamics in PH models and improved RV structure and function in PAB animals. PH models and PAB animals frequently exhibited similar results (73.1% concordance). Macitentan, sildenafil, and tadalafil improved most tested pathophysiological parameters in PH models, but almost none in PAB animals. Results are frequently not consistent with other studies, possibly due to the methodology, which greatly varied. Some research groups start treating the animals immediately, and others wait up to 4 weeks from model induction. Treatment duration and choice of anaesthetic are other important differences. This review shows that many drugs currently under research for PAH have a cardioprotective effect on animals that may translate to humans. However, a uniformization of methods may increase comparability between studies and, thus, improve translation to clinical trials.

Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors: Harms or Unexpected Benefits?

There is a need for innovative pharmaceutical intervention in light of the increasing prevalence of metabolic disease and cardiovascular disease. The kidneys' sodium-glucose cotransporter 2 inhibitors (SGLT2) receptors are targeted to reduce glucose reabsorption by SGLT2. Patients with type 2 diabetes mellitus (T2DM) benefit the most from reduced blood glucose levels, although this is just one of the numerous physiological consequences. To establish existing understanding and possible advantages and risks for SGLT2 inhibitors in clinical practice, this article will explore the influence of SGLT2 inhibitors on six major organ systems. In addition, this literature review will discuss the benefits and potential drawbacks of SGLT2 inhibitors on various organ systems and their potential application in therapeutic settings.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

Dapagliflozin, sildenafil and their combination in monocrotaline-induced pulmonary arterial hypertension

Background

Dapagliflozin, a selective inhibitor of sodium-glucose cotransporter 2 (SGLT2), can reduce cardiovascular events and mortality in patients with heart failure. A number of mechanisms have been proposed to explain the beneficial effects of SGLT2 inhibitors. The purpose of this study was to determine whether dapagliflozin can improve pulmonary vascular remodelling and the efficacy of dapagliflozin as an add-on therapy to sildenafil in rats with pulmonary arterial hypertension (PAH).

Methods

A monocrotaline (MCT)-induced PAH rat model was used in our study. MCT-injected rats were randomly divided into four groups and treated for 3 weeks with daily per os treatment with vehicle, dapagliflozin (1 mg/kg/day), sildenafil (25 mg/kg/day), or a combination of dapagliflozin (1 mg/kg/day) and sildenafil (25 mg/kg/day). Haemodynamic measurements, histological analysis, enzyme-linked immunosorbent assay and western blotting analysis were employed to detect the changes in PAH rats after treatments.

Results

Dapagliflozin significantly attenuated MCT-induced increases in right ventricular systolic pressure (RVSP) and right ventricular hypertrophy (RVH) in PAH rats. Dapagliflozin effectively decreased the thickening of pulmonary artery media and decreased the muscularization of pulmonary arterioles in PAH rats. Moreover, dapagliflozin attenuated nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome activation in lung tissues and the levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18) in plasma. However, dapagliflozin as an add-on therapy to sildenafil in rats with PAH did not show a more pronounced beneficial effect on right ventricular systolic pressure and pulmonary vascular remodelling in MCT rats than sildenafil alone.

Conclusions

Dapagliflozin reduces right ventricular systolic pressure and pulmonary vascular remodelling in a rat model of PAH. However, combination therapy with dapagliflozin and sildenafil was not more effective than monotherapy with sildenafil in PAH rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01939-7.