Effects of Protein Deficiency on Perinatal and Postnatal Health Outcomes

There are a variety of environmental insults that can occur during pregnancy which cause low birth weight and poor fetal health outcomes. One such insult is maternal malnutrition, which can be further narrowed down to a low protein diet during gestation. Studies show that perinatal protein deficiencies can impair proper organ growth and development, leading to long-term metabolic dysfunction. Understanding the molecular mechanisms that underlie how this deficiency leads to adverse developmental outcomes is essential for establishing better therapeuticstrategies that may alleviate or prevent diseases in later life. This chapter reviews how perinatal protein restriction in humans and animals leads to metabolic disease, and it identifies the mechanisms that have been elucidated, to date. These include alterations in transcriptional and epigenetic mechanisms, as well as indirect means such as endoplasmic reticulum (ER) stress and oxidative stress. Furthermore, nutritional and pharmaceutical interventions are highlighted to illustrate that the plasticity of the underdeveloped organs during perinatal life can be exploited to prevent onset of long-term metabolic disease

Islet-Like Cell Aggregates Generated from Human Adipose Tissue Derived Stem Cells Ameliorate Experimental Diabetes in Mice

BACKGROUND: Type 1 Diabetes Mellitus is caused by auto immune destruction of insulin producing beta cells in the pancreas. Currently available treatments include transplantation of isolated islets from donor pancreas to the patient. However, this method is limited by inadequate means of immuno-suppression to prevent islet rejection and importantly, limited supply of islets for transplantation. Autologous adult stem cells are now considered for cell replacement therapy in diabetes as it has the potential to generate neo-islets which are genetically part of the treated individual. Adopting methods of islet encapsulation in immuno-isolatory devices would eliminate the need for immuno-suppressants. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we explore the potential of human adipose tissue derived adult stem cells (h-ASCs) to differentiate into functional islet like cell aggregates (ICAs). Our stage specific differentiation protocol permit the conversion of mesodermic h-ASCs to definitive endoderm (Hnf3β, TCF2 and Sox17) and to PDX1, Ngn3, NeuroD, Pax4 positive pancreatic endoderm which further matures in vitro to secrete insulin. These ICAs are shown to produce human C-peptide in a glucose dependent manner exhibiting in-vitro functionality. Transplantation of mature ICAs, packed in immuno-isolatory biocompatible capsules to STZ induced diabetic mice restored near normoglycemia within 3-4 weeks. The detection of human C-peptide, 1155±165 pM in blood serum of experimental mice demonstrate the efficacy of our differentiation approach. CONCLUSIONS: h-ASC is an ideal population of personal stem cells for cell replacement therapy, given that they are abundant, easily available and autologous in origin. Our findings present evidence that h-ASCs could be induced to differentiate into physiologically competent functional islet like cell aggregates, which may provide as a source of alternative islets for cell replacement therapy in type 1 diabetes

Impairment of Rat Fetal Beta-Cell Development by Maternal Exposure to Dexamethasone during Different Time-Windows

Glucocorticoids (GCs) take part in the direct control of cell lineage during the late phase of pancreas development when endocrine and exocrine cell differentiation occurs. However, other tissues such as the vasculature exert a critical role before that phase. This study aims to investigate the consequences of overexposure to exogenous glucocorticoids during different time-windows of gestation for the development of the fetal endocrine pancreas

Taurine supplementation to a low protein diet during foetal and early postnatal life restores a normal proliferation and apoptosis of rat pancreatic islets.

AIMS/HYPOTHESIS: In our previous studies a low protein diet (8% vs 20%) given during foetal and early postnatal life induced abnormal development of the endocrine pancreas; beta-cell mass and islet-cell proliferation were reduced while apoptosis was increased. Taurine, an important amino acid for development was also reduced in maternal and foetal plasma of protein deficient animals. In this study we aim to evaluate the role of taurine in the alterations observed in rats after a low protein diet. METHODS: Four groups of rats were given either a control, a low protein, or control and low protein diets with 2.5% taurine in the drinking water. Diets were given to gestating and lactating mothers and to their pups until day 30. Beta and endocrine cell masses were analysed as well as DNA synthesis and apoptosis after taurine supplementation in foetuses and pups. We also investigated insulin like growth factor-II (IGF-II), inducible nitric oxide synthase (iNOS), and Fas by immunohistochemistry. RESULTS: In foetuses and neonates nourished with a low protein diet, taurine supplementation restored normal DNA synthesis and apoptosis. This led to adequate beta and endocrine cell mass in pups. In islet cells, immunoreactivity was increased for IGF-II, reduced for Fas and unchanged for iNOS after taurine supplementation. CONCLUSION/INTERPRETATION: Taurine supplementation to a low protein diet in foetal and early postnatal life prevents the abnormal development of the endocrine pancreas. The mechanisms by which taurine acts on DNA synthesis and apoptosis rate of endocrine cells involve IGF-II, Fas regulation but not iNOS

Angiogenesis in Developing Follicle and Corpus Luteum

Angiogenesis is a process of vascular growth that is mainly limited to the reproductive system in healthy adult animals. The development of new blood vessels in the ovary is essential to guarantee the necessary supply of nutrients and hormones to promote follicular growth and corpus luteum formation. In developing follicles, the pre-existing endothelial cells that form the vascular network in the theca layer markedly develop in response to the stimulus of several growth factors, mainly produced by granulosa cells, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). The angiogenic factors also promote vessel permeability, thus favouring the antrum formation and the events inducing follicle rupture. After ovulation, newly formed blood vessels cross the basement membrane between theca and granulosa layers and continue a rapid growth to sustain corpus luteum development and function. The length of luteal vascular growth varies in cycling and pregnant animals and among species; both angiogenesis and subsequent angioregression are finely regulated by systemic and local factors. The control of angiogenic development in the ovary could be a useful tool to improve animal reproductive performances