Cardioprotective effects of asiaticoside against diabetic cardiomyopathy: Activation of the AMPK/Nrf2 pathway.

Diabetic cardiomyopathy (DCM) is a chronic microvascular complication of diabetes that is generally defined as ventricular dysfunction occurring in patients with diabetes and unrelated to known causes. Several mechanisms have been proposed to contribute to the occurrence and persistence of DCM, in which oxidative stress and autophagy play a non-negligible role. Diabetic cardiomyopathy is involved in a variety of physiological and pathological processes. The 5' adenosine monophosphate-activated protein kinase/nuclear factor-erythroid 2-related factor 2 (AMPK/Nrf2) are expressed in the heart, and studies have shown that asiaticoside (ASI) and activated AMPK/Nrf2 have a protective effect on the myocardium. However, the roles of ASI and AMPK/Nrf2 in DCM are unknown. The intraperitoneal injection of streptozotocin (STZ) and high-fat feed were used to establish the DCM models in 100 C57/BL mice. Asiaticoside and inhibitors of AMPK/Nrf2 were used for intervention. Cardiac function, oxidative stress, and autophagy were measured in mice. DCM mice displayed increased levels of oxidative stress while autophagy levels declined. In addition, AMPK/Nrf2 was activated in DCM mice with ASI intervention. Further, we discovered that AMPK/Nrf2 inhibition blocked the protective effect of ASI by compound C and treatment with ML-385. The present study demonstrates that ASI exerts a protective effect against DCM via the potential activation of the AMPK/Nrf2 pathway. Asiaticoside is a potential therapeutic target for DCM.

RIP3 orchestrates oxidative stress and pyroptosis in doxorubicin-induced cardiotoxicity through regulation of AKT/Nrf2 signaling cascade.

This study was designed to explore the role of RIP3 in DOX-induced cardiotoxicity and its underlying molecular mechanisms. Our results demonstrate that RIP3 exacerbates DOX-induced cardiotoxicity through promoting oxidative stress and pyroptosis by regulating the AKT/Nuclear factor erythroid 2-related factor 2 (Nrf2) signal pathway. Inhibition of RIP3 using GSK-872 attenuated DOX-induced cardiac remodeling and contractile dysfunction. Moreover, using GSK-872 in vivo, the results revealed that inhibition of RIP3 alleviated DOX-induced cardiotoxicity by the resulting inhibition of oxidative stress and pyroptosis. In addition, inhibition of RIP3 increased the protein levels of AKT and Nrf2 in DOX-treated mouse hearts. Furthermore, the AKT inhibitor LY294002 lessened RIP3 reduction-offered protection against DOX-induced H9c2 cell injury by moderating oxidative stress and pyroptosis. Taken together, these data demonstrate that RIP3 activation orchestrates DOX-induced cardiotoxicity through elevated oxidative stress and pyroptosis in an AKT/Nrf2-dependent manner. Those findings highlight the clinical relevance and therapeutic potential of targeting RIP3 for the treatment of DOX-induced cardiotoxicity.

Transcatheter Mitral Valve-in-Valve Implantation Applying a Long Pre-Curved Sheath for Patients with Degenerated Bioprosthetic Mitral Valve.

Backgrounds: Percutaneous transseptal transcatheter mitral valve-in-valve implantation (TMViV) has become an alternative minimally invasive treatment choice for patients with degenerated mitral bioprosthesis and high surgical risk. However, transseptal approach is more technically challenging than transapical approach in TMViV procedures. Objective: The objective of this study was to introduce the experience of applying long pre-curved sheaths in transseptal TMViV procedures and to evaluate the effect of long pre-curved sheath techniques in TMViV procedures. Methods: Between January 2020 and December 2021, 27 patients with degenerated bioprosthetic mitral valve underwent TMViV procedures using a balloon-expandable valve via the transseptal approach. The regular 14/16F expandable sheath were used for low-profile delivery in first 10 cases, and 22F long pre-curved sheath were used in the next 17 cases during procedures. We retrospectively reviewed the catheter techniques, perioperative characteristics, and prognosis. The median follow-up time was 12 (1-21) months. To further scrutinize our data, we divided the group into the early 10 patients using 14/16F expandable sheath and the subsequent 17 patients with long pre-curved sheath in order to assess the impact of different sheaths and procedural details on outcomes. Results: Procedural success was obtained in all patients with no in-hospital mortality. Seventeen patients received 26 mm prostheses; the remaining ten patients received 29 mm prostheses. Post balloon dilatation was performed in one case. Total procedure time was (96.1 ± 28.2) min, the fluoroscopic time was (27.4 ± 6.5) min, and total contrast volume was (50.7 ± 10.1) mL. One patient received blood transfusion because of hemorrhage at the femoral puncture site. One patient received a permanent pacemaker implantation due to high-degree atrioventricular block at postoperative day 3. There were no other major post-procedure complications and the median length of hospital stay was 4 days. Twenty-five (92.6%) patients improved by ≥ 1 New York Heart Association (NYHA) functional class at 30 days. In subsequent sub analysis, there were shorter procedural time [(85.2 ± 24.3) vs. (115.2 ± 25.6) min, p = 0.0048] and shorter fluoroscopic time [(24.3 ± 5.2) vs. (31.3 ± 5.1) min, p = 0.0073] in cases with the long pre-curved sheath than ones with regular expandable sheath. The iatrogenic atrial septal defect (ASD) closure was performed because of the transeptal large right to left shunt in 2 cases with regular expandable sheath, but no patient needed intraoperative ASD closure in cases with the long pre-curved sheath. Conclusions: Transseptal TMViV using long pre-curved sheath could simplify transseptal approach with reliable outcomes for patients of degenerated mitral bioprosthesis.