Obesity causes an increase of PVAT and a hypertrophy of adipocytes around the blood vessels, and an increase of eosinophils, macrophages, T-cells, MCP-1, and TNF-alpha expression, but endothelial nitric oxide synthase expression decreases in these obese animals [132,134,135,136]. The gene discussed is CCL2; the disease is obesity due to melanocortin 4 receptor deficiency.