Taurine supplementation of a low protein diet fed to rat dams normalizes the vascularization of the fetal endocrine pancreas.
In rats, an isoenergetic low protein diet (LP) given throughout gestation perturbs the development of the endocrine pancreas by reducing beta-cell mass and islet vascularization at birth. Taurine, an important amino acid during development, has been found to be low in fetal and maternal plasma. When added to a LP diet, taurine normalizes beta-cell mass. Therefore, we investigated the ability of taurine to correct altered islet vascularization. Rats were given 20% [control (C)] or 8% (LP) protein in the diet with or without supplementation with 25 g/L taurine (T) in drinking water (C+T and LP+T) during gestation and lactation. Immunostaining for vascular endothelial growth factor (VEGF) and fetal liver kinase-1 (Flk-1), a VEGF receptor, was performed on fetal and neonatal pancreatic sections. Blood vessel density and blood vessel number were analyzed morphometrically on semi-thin sections. Taurine supplementation restored a normal volume and numerical density of vessels in fetal islets. The number of cells showing immunoreactivity for VEGF and Flk-1 was reduced by 33 and 45%, respectively, in islet cells from LP fetuses. In 1-mo-old pups, VEGF-positive cells remained decreased by nearly 22%. Both VEGF and Flk-1 were restored in pancreatic endocrine cells of fetuses and pups given taurine. The LP diet induced a threefold overexpression of Flk-1 in ductal cells, which contain precursors of beta cells. However, taurine supplementation was without effect. In conclusion, underexpression of VEGF and Flk-1 is associated with the lower fetal islet vascularization induced by the maternal malnutrition. The addition of taurine to the maternal diet prevents such damage and has a potential role in islet vasculogenesis.
Boujendar
Samira
S
Laboratoire de Biologie Cellulaire, World Health Collaborating Center for the Development of the Endocrine Pancreas, Université Catholique de Louvain, B-1348 Louvain-La-Neuve, Belgium.
Arany
Edith
E
Hill
David
D
Remacle
Claude
C
Reusens
Brigitte
B
D000818:Animals; D001808:Blood Vessels / Q000033:anatomy & histology; D018753:Diet, Protein-Restricted; D019587:Dietary Supplements; D016228:Endothelial Growth Factors / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000033:anatomy & histology* / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D007515:Islets of Langerhans / Q000196:embryology*; D008222:Lymphokines / Q000378:metabolism; D010183:Pancreatic Ducts / Q000196:embryology; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000008:administration & dosage*; D042461:Vascular Endothelial Growth Factor A; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D013654:Taurine; D040301:Vascular Endothelial Growth Factor Receptor-2