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Chronic renal insufficiency inexorably progresses in patients, such as it does after partial renal ablation in rats. However, the progression of renal diseases can be delayed by angiotensin II blockers that stabilize renal function or increaseGFR, even in advanced phases of the disease. Regression of glomerulosclerosis can be induced by angiotensin II antagonism, but the effect of these treatments on the entire vascular tree is unclear. Here, using microcomputed tomography and scanning electron microscopy,we compared the size and extension of kidney blood vessels in untreatedWistar rats with those in untreated and angiotensin II antagonist-treated MunichWistar Frömter (MWF) rats that spontaneously develop kidney disease with age. The kidney vasculature underwent progressive rarefaction in untreated MWF rats, substantially affecting intermediate and small vessels. Microarray analysis showed increased Tgf-b and endothelin-1 gene expression with age. Notably, 10-week inhibition of the renin-angiotensin system regenerated kidney vasculature and normalized Tgf-b and endothelin-1 gene expression in aged MWF rats. These changes were associated with reduced apoptosis, increased endothelial cell proliferation, and restoration of Nrf2 expression, suggesting mechanisms by which angiotensin II antagonism mediates regeneration of capillary segments. These results have important implications in the clinical setting of chronic renal insufficiency.

Type-1 Diabetes is generally treated with exogenous insulin administration. Despite treatment, a very common long term consequence of diabetes is the development of a disabling and painful peripheral neuropathy. The transplantation of pancreatic islets is an advanced alternative therapeutic approach, but its clinical application is still very limited, mainly because of the great number of islets required to complete the procedure and of their short-term survival. An intriguing method to improve the performance of pancreatic islets transplantation is the co-transplantation of Mesenchymal Stem Cells (MSCs), adult stem cells already known to support the survival of different cellular populations. In this proof-of-concept study, we demonstrated using an in vivo model of diabetes, the ability of allogenic MSCs to reduce the number of pancreatic islets necessary to achieve glycemic control in diabetic rats, and overall their positive effect on diabetic neuropathy, with the reduction of all the neuropathic signs showed after disease induction. The cutback of the pancreatic islet number required to control glycemia and the regression of the painful neuropathy make MSC co-transplantation a very promising tool to improve the clinical feasibility of pancreatic islet transplantation for diabetes treatment

The total mass of pancreatic islet cells is a critical factor in glucose metabolic control. The aim of the present study was to investigate whether in the Munich Wistar Fromter (MWF) rat, beside a reduction in the number of nephrons, there are also alterations in the number of pancreatic islets and of beta-cell mass. We also examined glucose metabolism, both in normal conditions and following intravenous glucose injection. The number of islets per pancreas, estimated by morphometrical analysis, was significantly lower in MWF rats than in Wistar rats (3,501 +/- 1,285 vs. 7,259 +/- 2,330 islet/rat, respectively). Also the mean number of islets per gram of body weight was significantly lower in MWF rats than in Wistar rats (18 +/- 7 in MWF rats vs. 28 +/- 10 islets/g bw in Wistar rats). Morphometric analysis of beta-cell mass showed an average of 77.1 +/- 7% islet cells staining for insulin in MWF rats and 83.9 +/- 2.1% in the control Wistar rats. Despite the lower number of islets and beta-cells, MWF and Wistar rats had comparable fasting blood glucose levels but significant differences in blood glucose following an intraperitoneal glucose tolerance test. In summary, pancreatic islets of MWF and Wistar rats showed a marked difference in morphometrical characteristics. While this difference is not associated with blood glucose levels, glucose metabolism after IPGTT between MWF and Wistar rats is significantly different. These data suggest that an inborn deficit in beta-cell mass of about 60% is responsible for altered glucose metabolism and could favor the development of diabetes.

The clinical usability of pancreatic islet transplantation for the treatment of type I diabetes, despite some encouraging results, is currently hampered by the short lifespan of the transplanted tissue. In vivo studies have demonstrated that co-transplantation of Mesenchymal Stem Cells (MSCs) with transplanted pancreatic islets is more effective with respect to pancreatic islets alone in ensuring glycemia control in diabetic rats, but the molecular mechanisms of this action are still unclear. The aim of this study was to elucidate the molecular mechanisms of the positive effect of MSCs on pancreatic islet functionality by setting up direct, indirect and mixed co-cultures. MSCs were both able to prolong the survival of pancreatic islets, and to directly differentiate into an "insulin-releasing" phenotype. Two distinct mechanisms mediated these effects: i) the survival increase was observed in pancreatic islets indirectly co-cultured with MSCs, probably mediated by the trophic factors released by MSCs; ii) MSCs in direct contact with pancreatic islets started to express Pdx1, a pivotal gene of insulin production, and then differentiated into insulin releasing cells. These results demonstrate that MSCs may be useful for potentiating pancreatic islets' functionality and feasibility.

Treatment of type-1diabetes with pancreatic islet transplantation is an intriguing therapeutic option, aimed to replace insulin administration, but very limited in clinical practice, mainly for the great number of islets necessary and for their short survival. Aim of this work is to verify the ability of Mesenchymal Stem Cells (MSCs) co-transplanted with Pancreatic Islets to improve the feasibility of this approach, by acting both on glycaemic control and on long term disease complications, such as the diabetic neuropathy. 5 groups were used (8 rats/group): a) healthy controls; b) Streptozotocin-induced diabetic rats; c) Diabetic rats transplanted with pancreatic islets (3000); d) Diabetic rats co-transplanted with pancreatic islets (2000) and MSCs (106); Diabetic rats treated with MSCs (106). Transplantations were performed after the assessment of neuropathic signs, such as the decrease of Nerve Conduction Velocity (NCV) and the impairment of nociceptive (thermal and mechanical) thresholds. The same parameters were evaluated two months after the transplantation. Diabetic rats transplanted only with pancreatic islets, or co-transplanted with MSCs and a suboptimal number of pancreatic islets, showed a marked and significant glycaemia value reduction, an improvement of thermal and mechanical sensitivity, and a nearly complete restoration of NCV with respect to diabetic-untreated rats. No differences were observed between diabetic rats and diabetic rats treated with only MSCs. Co-transplantation of MSCs with Pancreatic Islets allows to reduce the successful number of pancreatic islets, to obtain a better and more physiologic glycaemic control, and to induce the regression of painful neuropathy signs, thus ameliorating diabetes complications management

The cell-based therapy is a promising approach to treat many degenerative diseases such as type 1 Diabetes Mellitus (T1DM). Besides the exclusive pharmacological treatment for T1DM a new approach has been recently proposed for restoring of Beta cell mass by islet transplantation. One of the principal problems of this approach is the numerical and functional loss of transplanted islets. For these reasons new strategies are studied in order to increase islets survival. In our laboratories we have already demonstrated that rat Mesenchymal Stem Cells (rMSC) are able to promote islets survival in vitro and that rMSC, if cocultured with pancreatic islets, are able to express Pdx1, a gene involved in beta cell insulin secretion. The aim of this study is to verify the effect of human Mesenchymal Stem Cells (hMSC) on the survival and function of pancreatic islets. In order to clarify which mechanism could be involved in the putative positive effect we set up different culture conditions: direct coculture, in which hMSC were in direct contact with islets; indirect coculture in which hMSC and islets shared the medium; mix cocultured in which islets were both in direct contact and shared the medium with hMSC. Preliminary results demonstrate a positive effect of hMSC on islets survival. Now we are focusing on the effect on insulin secretion regulated by hMSC in the different coculture conditions.

Transplantation of pancreatic islets is an innovative and promising clinical option to treat patients with type 1 diabetes [1]. This is a minimally invasive therapeutic approach, which allows a good metabolic control and a long-term insulin independence [2]. The therapeutic feasibility of pancreatic islets transplantation is however limited by the poor yield of pancreatic islet explants and even more the immune graft rejection, which have as a consequence the very limited lifespan of transplanted tissue [3]. To avoid these side effects besides the treatment with immunosuppressive drugs, promising results have been obtained in vivo with the use of Mesenchymal Stem cells (MSCs), already known in literature to be able to support the cellular survival through direct contact [4, 5] by the release of trophic factors [6], and by their immunomodulatory properties [7]. By means of these particular features it can be surmised that MSCs may improve the survival of pancreatic islets and, therefore, the success of the transplantation. Several in vivo studies have demonstrated the positive effect of islet-MSC co-transplantation in diabetic rats, but the mechanisms of these encouraging results are still unknown [8]. In this in vitro study we shed light on the concealed molecular mechanisms of MSC positive action, by analyzing the effect of both direct and indirect co-cultures of rat MSCs with pancreatic islets.

Transplantation of pancreatic islets has become a promising clinical option to treat patients with type 1 diabetes, alternative to the standard therapy with insulin injections. Islet transplantation is a minimally invasive therapeutic approach, and it allows a better metabolic control and a long-term insulin independence in more than 80% of patients (Ryan et al., 2002). However this therapeutic treatment has some side effects, such as the poor yield of pancreatic islet explants and even more the immune graft rejection, which have as a consequence the very limited lifespan of transplanted pancreatic islets. To avoid these side effects several strategies have been proposed and, besides the treatment with immunosuppressive drugs, promising results have been obtained with the use of Mesenchymal Stem cells (MSCs), already known in literature to be able to support the survival of many cell types (Scuteri et al., 2006). Several in vivo studies have demonstrated that the concurrent transplantation of pancreatic islets with MSCs reduces the number of islets required to achieve glycemic control in diabetic rats, but the mechanisms of these encouraging results are still unknown (Figliuzzi et al., 2009). For these reasons in this in vitro study we characterized the effect of co-culture of rat MSC on survival and functioning of rat pancreatic islets, by evaluating for 4 weeks: i) MSC adhesion to pancreatic islets; ii) viability of pancreatic islets co-cultured with MSCs; iii) the expression of insulin after co-culture; iv) the ability of co-cultured pancreatic islets to correctly adjust insulin release after variation of glucose concentration. Our results demonstrated that MSCs are able to adhere to pancreatic islets, but to increase only partly the pancreatic islet survival, which retain the ability to express and correctly release insulin after glucose variation in medium culture. Noteworthy that the insulin level in the medium of co-cultured pancreatic islets is always higher