title: Aging and a long-term diabetes mellitus increase expression of 1 α-hydroxylase and vitamin D receptors in the rat liver.
abstract: Diabetes mellitus (DM) is a metabolic disorder associated with serious liver complications. As a metabolic chronic disease, DM is very common in the elderly. Recent studies suggest ameliorating effects of vitamin D on metabolic and oxidative stress in the liver tissue in an experimental model of DM. The aim of this study was to investigate the expression of vitamin D receptors (VDRs) and 1α-hydroxylase, the key enzyme for the production of active vitamin D form (calcitriol) in the liver during long-term diabetes mellitus type 1 (DM1) in aging rats. We performed immunohistochemical analysis of liver expression of 1α-hydroxylase and VDRs during aging in long-term streptozotocin-induced DM1. 1α-Hydroxylase was identified in the monocyte/macrophage system of the liver. In addition to the nuclear expression, we also observed the expression of VDR in membranes of lipid droplets within hepatocytes. Aging and long-term DM1 resulted in significant increases in the number of 1α-hydroxylase immunoreactive cells, as well as the percentage of strongly positive VDR hepatocytes. In conclusion, the liver has the capacity for active vitamin D synthesis in its monocyte/macrophage system that is substantially increased in aging and long-term diabetes mellitus. These conditions are also characterized by significant increases in vitamin D receptor expression in hepatocytes. The present study suggests that VDR signaling system could be a potential target in prevention of liver complications caused by diabetes and aging.
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Vuica
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
authors.forename: Lejla
authors.initials: L
authors.lastname: Ferhatović Hamzić
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Vukojević
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
authors.forename: Milka
authors.initials: M
authors.lastname: Jerić
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
authors.forename: Livia
authors.initials: L
authors.lastname: Puljak
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia.
authors.forename: Ivica
authors.initials: I
authors.lastname: Grković
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2, 21000 Split, Croatia. Electronic address: natalija.filipovic@mefst.hr.
authors.forename: Natalija
authors.initials: N
authors.lastname: Filipović
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000378:metabolism*; D000375:Aging; D000818:Animals; D003920:Diabetes Mellitus / Q000139:chemically induced / Q000378:metabolism*; D004195:Disease Models, Animal; D022781:Hepatocytes / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018167:Receptors, Calcitriol / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D018167:Receptors, Calcitriol; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase
keywords: 1α-Hydroxylase; Aging; Diabetes mellitus; Liver; VDR