Saluisn-β contributes to endothelial dysfunction in monocrotaline-induced pulmonary arterial hypertensive rats

Performance of oral Bosentan-loaded SNEDDS and S-SNEDDS tablets: Biodistribution in mice, echocardiography and histology studies in pulmonary arterial hypertension rat model

Bosentan monohydrate (BOS) is the most preferred molecule for treating the rare pulmonary arterial hypertension (PAH) disease. BOS shows low solubility and high variability when administered orally. This study evaluated the pharmacodynamic biodistribution, echocardiography, and histology results of BOS-loaded SNEDDS and BOS-loaded S-SNEDDS tablets. Pharmacodynamic biodistribution studies were conducted with male Balb/c mice (8 weeks old, 18-20 g) after oral administration. XenoLightTM DiR and VivoTag® 680XL fluorescent dyes were used to monitor biological distribution and absorption with the In Vivo Imaging System® (IVIS®). Pharmacodynamic echocardiography and histology studies were carried out with Wistar rats (8-10 weeks old, 250-300 g). The PAH rat model was successfully induced with monocrotaline (MCT), which is one dose (60  mg/kg) was intraperitoneally injected. The reference drug (Tracleer® 125 mg tablet) and BOS-loaded SNEDDS and S-SNEDDS tablets were administered as 50 mg/kg; 2 mL per os to the treatment groups. Pharmacodynamic biodistribution studies showed that real-time biodistribution in the body, ex-vivo region of interest (ROI) values of organs, and total fluorescence emission were increased (p < 0.05). It has been confirmed that the formulations enter the systemic circulation via the lymphatic system, do not have a first-pass effect in the liver, and show no emission in the liver. The echocardiographic study was performed for up to 14 days and no difference was found between the treatment groups which are the reference tablet (Tracleer®), BOS-loaded SNEDDS, and BOS-loaded S-SNEDDS tablet (p > 0.05). Hematoxylin and Eosin (H&E) and Immunohistochemical (IHC) staining were done for the histology studies. These studies showed that the BOS-loaded formulations have a similar therapeutic effect on histopathological phenomena in lung and liver tissues. As the histological evaluation results, lower-dose formulations were found to be more effective than the same dose reference tablet in terms of improvements in histological parameters (p < 0.05). Comprehensive and comparative in vitro and in vivo studies indicate that BOS-loaded formulations could be an alternative oral drug delivery system for PAH treatment compared to the reference product.

Downregulation of salusins alleviates hypertrophic cardiomyopathy via attenuating oxidative stress and autophagy

INTRODUCTION

Salusins, which are translated from the alternatively spliced mRNA of torsin family 2 member A (TOR2A), play a vital role in regulation of various cardiovascular diseases. However, it remains unclear precisely regarding their roles in hypertrophic cardiomyopathy (HCM). Therefore, this study was conducted to explore therapeutic effect and the underlying mechanisms of salusins on HCM.

MATERIAL AND METHODS

In vivo experiments, Sprague-Dawley rats were used to induce HCM model by angiotensin (Ang) II infusion for 4 weeks. The rats were randomly divided into four groups, namely, Saline + Control shRNA (n = 7), Ang II + Control shRNA (n = 8), Saline + TOR2A shRNA (n = 7), and Ang II + TOR2A shRNA groups (n = 8). After HCM induction, doppler echocardiography is recommended to evaluate heart function. In vitro experiments, primary neonatal rat cardiomyocytes (NRCMs) and cardiac fibroblasts (NRCFs) were obtained from newborn rats, and were treated with Ang II (10-6 M) for 24 h.

RESULTS

After treatment with Ang II, levels of salusin-α and salusin-β were elevated in serum and cardiac tissues of rats and in the neonatal rat cardiomyocytes and cardiac fibroblasts. Downregulation of salusins alleviated the Ang II-induced cardiac hypertrophy by suppressing the increased atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and beta-myosin heavy chain (β-MHC) and cardiac fibrosis by blocking collagen I, collagen III and transforming growth factor-beta (TGF-β), and it also attenuated oxidative stress by suppressing the increased reactive oxygen species (ROS) and malondialdehyde (MDA) levels and reversing the decreased superoxide dismutase (SOD) activity and autophagy by inhibiting the increased microtubule-associated protein light chain 3B (LC3B), Beclin1, autophagy related gene (Atg) 3 and Atg5 in the cardiac tissues of Ang II-infused rats and in the Ang II-treated NRCMs.

CONCLUSIONS

All these findings suggest that the levels of salusins were elevated in the HCM, and targeting of salusins contributes to alleviation of cardiac hypertrophy and fibrosis probably via attenuating oxidative stress and autophagy. Accordingly, targeting of salusins may be a strategy for HCM therapy.