Key result
Coronary artery contractility was significantly lower in Zucker diabetic fatty rats than in lean rats, driven by L-type calcium channel dysregulation and reversed by metformin.
Why the study?
Diabetic coronary artery injury is closely associated with Ca2+ dysregulation, but the underlying mechanism remains unclear.
Does calcium dysregulation contribute to impaired coronary artery contraction in type 2 diabetic rats, and can metformin reverse this?
Does calcium dysregulation contribute to impaired coronary artery contraction in type 2 diabetic rats, and can metformin reverse this?
Dysregulation of L-type calcium channels contributes to decreased coronary artery contractility in type 2 diabetes, which can be reversed by metformin in a rat model.
Answers are grounded in this paper and cite their sources.
Suggests Ca2+ dysregulation in diabetic rat coronaries; hypothesis-generating and leaves open human translation.
Diabetic coronary artery injury is closely associated with Ca 2+ dysregulation, although the underlying mechanism remains unclear. This study explored the role and mechanism of Ca 2+ handling in coronary artery dysfunction in type 2 diabetic rats. Zucker diabetic fatty (ZDF) rats were used as the type 2 diabetes mellitus model. The contractility of coronary artery rings induced by KCl, CaCl 2 , 5‐HT and U46619 was significantly lower in ZDF rats than in Zucker lean rats. Vasoconstriction induced by 5‐HT and U46619 was greatly inhibited by nifedipine. However, in the presence of 1 μM nifedipine or in the Ca 2+ ‐free KH solution containing 1 μM nifedipine, there was no difference in the vasoconstriction between Zucker lean and ZDF rats. Store‐operated calcium channels (SOCs) were not involved in coronary vasoconstriction. The downregulation of contractile proteins and the upregulation of synthesized proteins were in coronary artery smooth muscle cells (CASMCs) from ZDF rats. Metformin reversed the reduction of vasoconstriction in ZDF rats. Taken together, L‐type calcium channel is important for regulating the excitation–contraction coupling of VSMCs in coronary arteries, and dysregulation of this channel contributes to the decreased contractility of coronary arteries in T2DM.
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Liu et al. (2022) studied Type 2 diabetes mellitus. Type 2 diabetes (ZDF rat model) vs. Zucker lean rats was evaluated on Contractility of coronary artery rings induced by KCl, CaCl2, 5-HT and U46619. Coronary artery contractility was significantly lower in Zucker diabetic fatty rats than in lean rats, driven by L-type calcium channel dysregulation and reversed by metformin.
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