PI3 and obesity due to melanocortin 4 receptor deficiency: To evaluate the physiological effects of elafin in diet-induced obesity, hyperglycemia, or hypercholesterolemia, 8-week-old male c57BL/6J wild-type mice received 8-week regular diet (RD), high-fat diet (HFD), or low-fat high-cholesterol diet (HCD) treatment, followed by intravenous injection with either control lentivirus (control-LV) or elafin-expressing lentivirus (elafin-LV)5.