Empagliflozin suppresses mitochondrial reactive oxygen species generation and mitigates the inducibility of atrial fibrillation in diabetic rats

Takuya Koizumi; Masaya Watanabe; Takashi Yokota; Masumi Tsuda; Haruka Handa; Jiro Koya; Kotaro Nishino; Daishiro Tatsuta; Hiroyuki Natsui; Takahide Kadosaka; Taro Koya; Motoki Nakao; Hikaru Hagiwara; Rui Kamada; Taro Temma; Shinya Tanaka; Toshihisa Anzai

doi:10.3389/fcvm.2023.1005408

Empagliflozin suppresses mitochondrial reactive oxygen species generation and mitigates the inducibility of atrial fibrillation in diabetic rats

Front Cardiovasc Med. 2023 Feb 6:10:1005408. doi: 10.3389/fcvm.2023.1005408. eCollection 2023.

Authors

Takuya Koizumi¹, Masaya Watanabe¹, Takashi Yokota², Masumi Tsuda³, Haruka Handa⁴, Jiro Koya¹, Kotaro Nishino¹, Daishiro Tatsuta¹, Hiroyuki Natsui¹, Takahide Kadosaka¹, Taro Koya¹, Motoki Nakao¹, Hikaru Hagiwara^{1

5}, Rui Kamada⁶, Taro Temma¹, Shinya Tanaka⁵, Toshihisa Anzai¹

Affiliations

¹ Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
² Institute of Health Science Innovation for Medical Care, Hokkaido University Hospital, Sapporo, Japan.
³ Department of Cancer Pathology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
⁴ Department of Molecular Biology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
⁵ Kushiro City General Hospital, Kushiro, Japan.
⁶ Hanaoka Seishu Memorial Hospital, Sapporo, Japan.

Abstract

Introduction: Recent studies have demonstrated that sodium-glucose co-transporter-2 inhibitors (SGLT2-i) reduce the risk of atrial fibrillation (AF) in patients with diabetes mellitus (DM), in which oxidative stress due to increased reactive oxygen species (ROS) contributes to the pathogenesis of AF. We aimed to further investigate this, and examine whether the SGLT2-i empagliflozin suppresses mitochondrial-ROS generation and mitigates fibrosis.

Methods: A high-fat diet and low-dose streptozotocin treatment were used to induce type-2 DM (T2DM) in Sprague-Dawley rats. The rats were randomly divided into three groups: control, DM, and DM treated with empagliflozin (30 mg/kg/day) for 8 weeks. The mitochondrial respiratory capacity and ROS generation in the atrial myocardium were measured using a high-resolution respirometer. Oxidative stress markers and protein expression related to mitochondrial biogenesis and dynamics as well as the mitochondrial morphology were examined in the atrial tissue. Additionally, mitochondrial function was examined in H9c2 cardiomyoblasts. Atrial tachyarrhythmia (ATA) inducibility, interatrial conduction time (IACT), and fibrosis were also measured.

Results: Inducibility of ATA, fibrosis, and IACT were increased in rats with DM when compared to controls, all of which were restored by empagliflozin treatment. In addition, the rats with DM had increased mitochondrial-ROS with an impaired complex I-linked oxidative phosphorylation capacity. Importantly, empagliflozin seemed to ameliorate these impairments in mitochondrial function. Furthermore, empagliflozin reversed the decrease in phosphorylated AMPK expression and altered protein levels related to mitochondrial biogenesis and dynamics, and increased mitochondrial content. Empagliflozin also improved mitochondrial function in H9c2 cells cultured with high glucose medium.

Discussion: These data suggest that empagliflozin has a cardioprotective effect, at least in part, by reducing mitochondrial ROS generation through AMPK signaling pathways in the atrium of diabetic rats. This suggests that empagliflozin might suppress the development of AF in T2DM.

Keywords: SGLT2 inhibitor; diabetes; empagliflozin; mitochondria; reactive oxygen species.

Grants and funding

This work was partly supported by grants from the Japan Society for the Promotion of Science KAKENHI (Grant Nos.: 22K08197 to MW, 18K15874 to TT, and 19K17584 to RK). This study also supported by grants from Boehringer Ingelheim. Empagliflozin was also supplied by Boehringer Ingelheim. However, Boehringer Ingelheim had no role in data collection, analysis, or interpretation.