Effect of a Low Protein Diet during Pregnancy on the Fetal Rat Endocrine Pancreas

Abstract

The administration of a low protein (LP, 8% protein/dry matter) but isocaloric diet to gestating rats did not affect their fertility, but slightly reduced the quantity of food intake as well as body weight gain. The LP diet also did not affect the placental weight, but the weight of the offspring was decreased. Accordingly the fetal endocrine pancreas was altered by the LP diet. Two different morphometric analyses showed that in the LP neonate B-cell proliferation and islet size were reduced in the head of the pancreas. In the pancreatic tail, these parameters were also decreased but to a lesser extend. Islet vascularization in the neonates was dramatically reduced in both parts of the pancreas when the mothers were fed with the LP diet.

The intrauterine metabolic environment modulates the gene expression pattern in fetal rat islets: prevention by maternal taurine supplementation

“…In contrast, many genes involved in cell cycle and cell proliferation were changed by the LP diet and their expression restored by taurine. This may fit in with the lengthening of the beta cell cycle and the lower proliferation rate that we previously described in fetuses from dams fed an LP diet [8,13,37]. Evidence for the involvement of the IGF gene/protein family in beta cell development is abundant.…”

“…IGF-2 exerts its mitogenic and antiapoptotic action via its binding to the IGF-1 receptor. IGF-1 receptor knockout mice have 50% reduction in their beta cell mass [40] and deletion of the IGF-1 and insulin receptors in the beta cell induced reduced beta cell mass and increased apoptosis and default in insulin secretion, three alterations that were also observed in the LP fetal islets [8,11,14].…”

“…One group of pregnant rats was fed a normal control diet (20% protein content), a second group an isoenergetic LP diet (8% [wt/wt] protein content) and a third was fed the LP diet supplemented with taurine (LPT) (2.5% [wt/wt]; Sigma Chemical, Brussels, Belgium) in the drinking water. The composition of both diets has been described previously [8]. Diets were purchased from Hope Farms (Woerden, The Netherlands).…”

“…A recent review study suggested that inadequate maternal nutrition might disturb the development of the fetus, which must adopt strategies to ensure survival that will programme its future health [3]. In experimental animal models, alteration of the intrauterine environment induced, for example, by gestational diabetes [4], placental insufficiency [5,6] or poor maternal nutrition [7][8][9][10][11] compromise the development of endocrine pancreas in the progeny and impact on its future health even in the subsequent generation [4,6,12]. Reduction of food intake by 50% in rats during gestation reduced the beta cell mass in offspring at birth by 30% [9].…”

“…Reduction of food intake by 50% in rats during gestation reduced the beta cell mass in offspring at birth by 30% [9]. When maternal diet was reduced in protein content during gestation, a number of findings were observed: reduction in beta cell mass due to diminished proliferation [8,13], enhanced apoptosis [11,13], reduced insulin secretion in vitro from isolated islets [14], impaired islet vascularisation [8,15] and enhanced sensitivity to cytotoxic effects of cytokines in vitro [11]. Increased susceptibility to cytokine cytotoxicity and lower insulin secretion persisted in adulthood despite limiting the low-protein (LP) diet to the period of gestation and lactation [7,12].…”