title: New perspectives of vesicular monoamine transporter 2 chemical characteristics in mammals and its constant expression in type 1 diabetes rat models.
abstract: Vesicular monoamine transporter 2 (VMAT2) has been exploited as a biomarker of β-cell mass in human islets. However, a current report suggested no immunoreactivity of VMAT2 in the β cells of rat islets. To investigate the cellular localization of VMAT2 in islets further, the pancreatic tissues from monkeys and humans were compared with those of rats and mice. The study was performed using among-species comparisons and a type 1 diabetes model (T1DM) for rats by Western blotting, double-label immunofluorescence, and confocal laser scanning microscopy. We found that VMAT2-immunoreactivity (IR) was distributed peripherally in the islets of rodents, but was widely scattered throughout the islets of primates. Consistent with rodent islets, VMAT2-IR did not exist in insulin (INS)-IR cells but was abundantly present in glucagon (GLU)-IR and pancreatic polypeptide (PP)-IR cells in monkey and human islets. VMAT2-IR had no colocalization with INS-IR in any part of the rat pancreas (head, body, and tail). INS-IR cells were reduced dramatically in T1DM rat islets, but no significant alteration in the proportion of VMAT2-IR cells and GLU-IR cells was observed. Furthermore, a strong colocalization of VMAT2-IR with GLU-IR was distributed in the peripheral regions of diabetic islets. For the first time, the current study demonstrates the presence of VMAT2 in α cells and PP cells but not in β cells in the islets of monkeys and humans. This study provides convinced morphologic evidence that VMAT2 is not present in β cells. There needs to be studies for new markers for β cell mass.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Hong
authors.affiliation: Department of Human Anatomy, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Rui-Fang
authors.initials: RF
authors.lastname: Fan
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Human Anatomy, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Rui-Pan
authors.initials: RP
authors.lastname: Zheng
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Human Anatomy, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medicinal Sciences, Capital Medical University, Beijing 100069, China. Electronic address: zhu_jx@ccmu.edu.cn.
authors.forename: Jin-Xia
authors.initials: JX
authors.lastname: Zhu
mesh_terms: D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D004195:Disease Models, Animal; D007515:Islets of Langerhans / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism*
chemical_list: C493454:Slc18a2 protein, rat; D050493:Vesicular Monoamine Transport Proteins