TRPV1-mediated UCP2 upregulation ameliorates hyperglycemia-induced endothelial dysfunction

Area of Science:

• Cardiovascular Research
• Endothelial Biology
• Mitochondrial Function

Background:

• Diabetic cardiovascular complications involve oxidative stress and endothelial dysfunction.
• Uncoupling protein 2 (UCP2) regulates mitochondrial reactive oxygen species (ROS) and can counteract oxidative stress.
• Transient receptor potential vanilloid 1 (TRPV1) activation by capsaicin shows potential in preventing cardiometabolic disorders.

Purpose of the Study:

• To investigate the effect of capsaicin on endothelial UCP2 and oxidative stress in vitro and in vivo.
• To determine if TRPV1 activation by capsaicin attenuates hyperglycemia-induced endothelial dysfunction via a UCP2-mediated antioxidant effect.

Main Methods:

• Experiments utilized TRPV1(-/-), UCP2(-/-), and db/db mice, alongside wild-type controls.
• Mice received dietary capsaicin for 14 weeks; arteries and endothelial cells were isolated for functional, immunohistological, and molecular analyses.
• Endothelial function, ROS production, and nitric oxide (NO) levels were assessed.

Main Results:

• Capsaicin reversed high-glucose-induced decreases in TRPV1 and protein kinase A (PKA) phosphorylation in endothelial cells.
• Capsaicin reduced ROS production and restored endothelial function in a TRPV1 and UCP2-dependent manner.
• Dietary capsaicin improved vascular oxidative stress, increased NO levels, and promoted endothelium-dependent relaxation in diabetic mice.

Conclusions:

• TRPV1 activation by capsaicin protects against hyperglycemia-induced endothelial dysfunction.
• The protective mechanism involves the PKA/UCP2 pathway, mitigating oxidative stress.
• Capsaicin represents a potential therapeutic strategy for diabetic vascular complications.