Lineage tracing and resulting phenotype of haemopoietic-derived cells in the pancreas during beta cell regeneration

Aims Transplantation of bone marrow-derived haemopoietic stem cells following streptozotocin (STZ) treatment to induce pancreatic beta cell loss in mice causes the partial regeneration of beta cell mass, with many haemopoietic cells demonstrating endothelial cell markers. This study used genetically tagged haemopoietic lineage-derived cells to determine how endogenous cells are mobilised following beta cell loss and subsequent replacement. Methods A double transgenic mouse model, Vav-iCre; R26R-enhanced yellow fluorescent protein (YFP), was used where only haemopoietic lineage cells expressed the Vavl gene promoter allowing expression of the YFP reporter gene. Between postnatal days 2 and 4 mice were injected with STZ or vehicle (control) and body weight and glycaemia were monitored. Mice were killed between days 10 and 130, and the pancreases were examined by immunofluorescence microscopy. Results YFP-expressing cells infiltrated the pancreas at all ages, being present around newly forming islets at the pancreatic ducts, and within larger islets. Small numbers of YFP-positive cells (\u3c5%) co-stained for the macrophage markers F4/80 or Mac1, for cytokeratin 19, or for the transcription factor pancreatic and duodenal homeobox 1 (PDX-1), but no co-localisation was seen with insulin or other endocrine hormones. Within islets approximately 30% of YFP-positive cells co-stained for the endothelial cell marker CD31, and following STZ the number of haemopoietic-derived cells, and the proportion that were CD31-positive, both significantly increased after 21 and 40 days, coincident with a partial replacement of beta cells. Conclusions Our results suggest that following beta cell loss endogenous haemopoietic-lineage cells contribute to intra-islet angiogenesis, which supports a partial recovery of beta cell mass. © Springer-Verlag 2010

Susceptibility to fatty acid-induced β-cell dysfunction is enhanced in prediabetic diabetes-prone biobreeding rats: A potential link between β-cell lipotoxicity and islet inflammation

β-Cell lipotoxicity is thought to play an important role in the development of type 2 diabetes. However, no study has examined its role in type 1 diabetes, which could be clinically relevant for slow-onset type 1 diabetes. Reports of enhanced cytokine toxicity in fat-laden islets are consistent with the hypothesis that lipid and cytokine toxicity maybe synergistic. Thus, β-cell lipotoxicity could be enhanced in models of autoimmune diabetes. To determine this, we examined the effects of prolonged free fatty acids elevation on β-cell secretory function in the prediabetic diabetes-prone BioBreeding (dp-BB) rat, its diabetes-resistant BioBreeding (dr-BB) control, and normal Wistar-Furth (WF) rats. Rats received a 48-h iv infusion of saline or Intralipid plus heparin (IH) (to elevate free fatty acid levels ∼2-fold) followed by hyperglycemic clamp or islet secretion studies ex vivo. IH significantly decreased β-cell function, assessed both by the disposition index (insulin secretion corrected for IH-induced insulin resistance) and in isolated islets, in dp-BB, but not in dr-BB or WF, rats, and the effect of IH was inhibited by the antioxidant N-acetylcysteine. Furthermore, IH significantly increased islet cytokine mRNA and plasma cytokine levels (monocyte chemoattractant protein-1 and IL-10) in dp-BB, but not in dr-BB or WF, rats. All dp-BB rats had mononuclear infiltration of islets, which was absent in dr-BB and WF rats. In conclusion, the presence of insulitis was permissive for IH-induced β-cell dysfunction in the BB rat, which suggests a link between β-cell lipotoxicity and islet inflammation. Copyright © 2013 by The Endocrine Society

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

Maternal Undernutrition and Long-term Effects on Hepatic Function

Undernutrition in utero, regardless of the source, can impair proper liver development leading to long-term metabolic dysfunction. Understanding the molecular mechanisms underlying how nutritional deficits during perinatal life lead to permanent alterations in hepatic gene expression will provide better therapeutic strategies to alleviate the undernourished liver in postnatal life. This chapter addresses the different experimental models of undernutrition in utero, and highlights the direct and indirect mechanisms involved leading to metabolic diseases in the liver. These include hypoxia, oxidative stress, epigenetic alterations, and endoplasmic reticulum (ER) stress. In addition, promising perinatal nutritional and pharmaceutical interventions are highlighted which illustrate how the placidity of the developing liver can be exploited to prevent the onset of long-term metabolic disease

EFFECTS OF TOBACCO-SMOKE EXTRACTS ON THE ULTRASTRUCTURE OF FIBROBLASTS IN CULTURE

International audiencexx

Spatiotemporally-induced over expression of NKx2.2 in pancreatic tissue

104 p. : ill. ; 22 cm. 2nd printing.https://digitalcommons.pittstate.edu/ertman/1093/thumbnail.jp

[Under-hydroxylation of collagen synthesized by cultured fibroblasts]

International audienceThe collagen secreted by dermal fibroblast cell cultures, previously labelled with 3H-proline, was extracted and purified by carboxymethyl cellulose. The ratio of hydroxyproline to proline showed that the collagen produced by cell cultures may be under-hydroxylated in comparison to the ratio observed in the types of collagen extracted from human skin. Then, it is concluded that it is not sufficient to determine only the hydroxyproline content for a collagen biosynthesis study in cell cultures. This low hydroxyproline content may explain the rapid catabolism of a part os newly synthetized collagen in vitro.The collagen secreted by dermal fibroblast cell cultures, previously labelled with 3H-proline, was extracted and purified by carboxymethyl cellulose. The ratio of hydroxyproline to proline showed that the collagen produced by cell cultures may be under-hydroxylated in comparison to the ratio observed in the types of collagen extracted from human skin. Then, it is concluded that it is not sufficient to determine only the hydroxyproline content for a collagen biosynthesis study in cell cultures. This low hydroxyproline content may explain the rapid catabolism of a part os newly synthetized collagen in vitro