However, in pathological conditions such as obesity, PVAT undergoes significant changes, becoming predominantly composed of white adipocytes, and this results in the release of pro-inflammatory adipokines such as leptin, visfatin, chemerin, resistin, apelin, TNFα, monocyte chemoattractant protein-1 (MCP-1 or CCL2), IL-1β, IL-6, and IL-8 [72]. Here, APLN is linked to obesity due to melanocortin 4 receptor deficiency.