HIF1A and obesity due to melanocortin 4 receptor deficiency: Abnormal hypoxia signalling observed in rodents is also mirrored by human AT during obesity, where a reduced oxygen partial pressure (PO2) and/or overexpression of HIF1α in SAT, specifically in AT-derived macrophages (ATMs), have been identified in individuals with metabolically unhealthy obesity compared with lean individuals, although the clinical significance of AT hypoxia is debatable [76–79].