Expression of nerve growth factor in human pancreatic beta cells.
Nerve growth factor (NGF) is an important modulator of rat pancreatic beta-cell physiology in vitro. In this study, we analysed the expression of NGF, TrkA and insulin in human pancreatic islets from normal, ductal adenocarcinoma and insulinoma-afflicted samples, using double immunofluorescent labelling and confocal microscopy. We found that in normal human pancreas, insulin and NGF are co-expressed in beta cells. Moreover, similar to previous observations in rat, the high affinity NGF receptor TrkA is also expressed in beta cells. Pancreatic beta cells in normal islets from adenocarcinoma and mucinous cystadenocarcinoma patients also expressed NGF. In 2 out of 15 exocrine tumour samples, NGF was detected also in the tissue surrounding the islets, while 2 out of 13 adenocarcinoma tumours expressed this growth factor. In five insulinoma samples, we observed weaker immunofluorescent labelling of insulin and NGF in the neoplastic tissue, compared to the islets not afflicted by the tumour, which may be a consequence of increased hormone secretion rate. We demonstrate that human beta cells express TrkA and NGF. These findings are consistent with the hypothesis that NGF modulates insulin secretion through a paracrine/autocrine loop, similar to the one observed in cultured rat beta cells.
Vidaltamayo
Román
R
Department of Biophysics, Instituto de Fisiología Celular Universidad Nacional Autónoma de Mexico, UNAM Mexico.
Mery
Carlos M
CM
Angeles-Angeles
Arturo
A
Robles-Díaz
Guillermo
G
Hiriart
Marcia
M
D000230:Adenocarcinoma / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D002352:Carrier Proteins / Q000096:biosynthesis; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D020932:Nerve Growth Factor / Q000096:biosynthesis*; D010190:Pancreatic Neoplasms / Q000378:metabolism; D020917:Receptor, trkA
D002352:Carrier Proteins; D007328:Insulin; D008565:Membrane Proteins; D020932:Nerve Growth Factor; D020917:Receptor, trkA