Imeglimin exerts favorable effects on pancreatic β-cells by improving morphology in mitochondria and increasing the number of insulin granules
Junpei Sanada, Atsushi Obata, Yoshiro Fushimi, Tomohiko Kimura, Masashi Shimoda, Tomoko Ikeda, Yuka Nogami, Yoshiyuki Obata, Yuki Yamasaki, Shuhei Nakanishi, Tomoatsu Mune, Kohei Kaku, Hideaki Kaneto
Abstract
Imeglimin is a new anti-diabetic drug commercialized in Japan (Twymeeg®) and has been drawing much attention in diabetes research area as well as in clinical practice. In this study, we evaluated the effect of imeglimin on pancreatic β-cells. First, single-dose administration of imeglimin enhanced insulin secretion from β-cells and decreased blood glucose levels in type 2 diabetic db/db mice. In addition, single-dose administration of imeglimin significantly augmented insulin secretion in response to glucose from islets isolated from non-diabetic db/m mice. Second, during an oral glucose tolerance test 4-week chronic treatment with imeglimin enhanced insulin secretion and ameliorated glycemic control in diabetic db/db mice. Furthermore, the examination with electron microscope image showed that imeglimin exerted favorable effects on morphology in β-cell mitochondria and substantially increased the number of insulin granules in type 2 diabetic db/db and KK-Ay mice. Finally, imeglimin reduced the percentage of apoptotic β-cell death which was accompanied by reduced expression levels of various genes related to apoptosis and inflammation in β-cells. Taken together, imeglimin directly enhances insulin secretion in response to glucose from β-cells, increases the number of insulin granules, exerts favorable effects on morphology in β-cell mitochondria, and reduces apoptotic β-cell death in type 2 diabetic mice, which finally leads to amelioration of glycemic control.