Pioglitazone prevents hyperglycemia induced decrease of AdipoR1 and AdipoR2 in coronary arteries and coronary VSMCs

Area of Science:

• Cardiovascular Research
• Metabolic Diseases
• Pharmacology

Background:

• Adiponectin receptors (AdipoR1/R2) are crucial in inflammatory diseases like diabetes and atherosclerosis.
• Previous research indicated varied AdipoR regulation by pioglitazone, but their expression in coronary arteries and VSMCs was unstudied.
• This study investigated pioglitazone's effects on AdipoRs in coronary arteries and VSMCs, both in vitro and in vivo.

Purpose of the Study:

• To examine the impact of pioglitazone on adiponectin receptor expression in coronary arteries and vascular smooth muscle cells (VSMCs).
• To evaluate pioglitazone's therapeutic potential in a rat model of diabetes and atherosclerosis.
• To elucidate the role of PPAR-γ activation in pioglitazone's effects on coronary inflammation.

Main Methods:

• Male Sprague-Dawley rats were divided into Control, Diabetes Mellitus (DM), and Pioglitazone-treated (PIO) groups.
• In vivo assessment included blood pressure, serum markers (adiponectin, glucose, insulin, lipids), and gene expression (AdipoR1/R2, TNF-α) in coronary arteries.
• In vitro studies used rat coronary VSMCs treated with pioglitazone, a PPAR-γ antagonist (GW9662), and high glucose to assess AdipoR1/R2, TNF-α, and PPAR-γ expression.

Main Results:

• Pioglitazone treatment significantly reduced cholesterol, triglycerides, fasting insulin, and TNF-α levels compared to the DM group (p<0.05).
• In vivo, pioglitazone increased AdipoR1 and AdipoR2 expression in coronary arteries, which were decreased in the DM group (p<0.05).
• In vitro, pioglitazone downregulated TNF-α, induced PPAR-γ, and prevented high glucose-induced decreases in AdipoR1/R2 expression (p<0.05); these effects were abolished by GW9662.

Conclusions:

• Pioglitazone ameliorates coronary insulin resistance and upregulates AdipoR1/R2 expression in diabetic conditions.
• Pioglitazone demonstrates anti-atherogenic properties by activating PPAR-γ and suppressing TNF-α in coronary arteries and VSMCs.
• The findings highlight pioglitazone's therapeutic potential for managing diabetic cardiovascular complications.