NPY and nutritional deficiency disease: The reason might be that severe malnutrition and hypermetabolism accompany the progression of liver cirrhosis, and as an early indicator of malnutrition, the increase of Ghrelin reflects an adaptive compensatory mechanism, which is to activate the hypothalamus NPY/AgRP neurons and Ghrelin-GH-IGF-I growth axis by increasing the expression of Ghrelin, and thus stimulate feeding and maintain energy homeostasis (Elbadri et al., 2011; Quiñones et al., 2020).