Introducing a new experimental islet transplantation model using biomimetic hydrogel and a simple high yield islet isolation technique

Background: Islet transplantation could be an ideal alternative treatment to insulin therapy for type 1 diabetes Mellitus [T1DM]. This clinical and experimental field requires a model that covers problems such as requiring a large number of functional and viable islets, the optimal transplantation site, and the prevention of islet dispersion. Hence, the methods of choice for isolation of functional islets and transplantation are crucial

Methods: The present study has introduced an experimental model that overcomes some critical issues in islet transplantation, including in situ pancreas perfusion by digestive enzymes through common bile duct. In comparison with conventional methods, we inflated the pancreas in Petri dishes with only 1 ml collagenase type XI solution, which was followed by hand-picking isolation or Ficoll gradient separation to purify the islets. Then we used a hydrogel composite in which the islets were embedded and transplanted into the peritoneal cavity of the streptozotocin-induced diabetic C57BL/6 mice

Results: As compared to the yield of the classical methods, in our modified technique, the mean yield of isolation was about 130-200 viable islets/mouse pancreas. In vitro glucosemediated insulin secretion assay indicated an appropriate response in isolated islets. In addition, data from in vivo experiments revealed that the allograft remarkably maintained blood glucose levels under 400 mg/dl and hydrogel composite prevents the passage of immune cells

Conclusion: In the model presented here, the rapid islet isolation technique and the application of biomimetic hydrogel wrapping of islets could facilitate islet transplantation procedures

Tumor associated mesenchymal stromalcells show higher immunosuppressiveand angiogenic properties compared toadipose derived MSCs

Background: Differentiation, migratory properties and availability of MesenchymalStromal Cells [MSC] have become an important part of biomedical research. However,the functional heterogeneity of cells derived from different tissues has hamperedproviding definitive phenotypic markers for these cells

Objective: To characterize andcompare the phenotype and cytokines of adipose derived MSCs [AD-MSCs] andtumoral-MSCs [T-MSCs] isolated from mammary tumors of BALB/c mice

Methods:Immunophenotyping and in vitro differentiation tests were used for MSCcharacterization. Cytokine and enzyme profiles were assessed using ELISA and RealtimePCR, respectively

Results: T-MSCs expressed significantly higher levels of HLADR[p=0.04]. Higher levels of PGE2 and COX-2 enzyme were also observed in TMSCs[p=0.07 and p=0.00, respectively]. Additionally, T-MSCs expressed higher levelsof iNOS and MMP9 [p=0.01 and p=0.01, respectively]. T-MSCs were also able toinduce higher levels of proliferation and migration of HUVEC endothelial cells inwound scratch assay compared to AD-MSCs [p=0.015]

Conclusion: Functionaldifferences showed by the surface markers of MSCs, cytokine and enzyme productionindicate the effect of different microenvironments on MSCs phenotype and function

Comparative study of the effect of LPS on the function of BALB/c and C57BL/6 peritoneal macrophages

Macrophages influence their environment and surrounding immune cells as soon as stimulators affect them. Different sources of macrophages induce different reactions in their neighboring immune cells,which result in non-uniform immunologic outcomes. In this experimental research, we compare the behavior of peritoneal macrophages to lipopolysaccharide [LPS] stimulation from BALB/cmice as an indicator of a type 2 immune response and from C57BL/6 mice as an indicator of a type 1 immune response. In this experimental study, peritoneal macrophages prepared from thioglycolate stimulated BALB/c and C57BL/6 micewere treated with 1microg/ml LPS. At different time points after LPS treatment, nitric oxide [NO], interferon gamma [IFN-gamma]. interleukin 4 [IL-4],transforming growth factor beta[1] [TGF-beta[1]], interleukin 17 [IL-17], and interleukin 10[IL-10] production were measured in the supernatants of all macrophage cultures.Indoleamine 2, 3 dioxygenase [IDO] and phagocytic activitywere analyzed in the different experimental groups. The supernatant effects of LPS-treated macrophages on splenocyte proliferation was assessed by the colorimetric method using a 3-[4,5-Dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide [MTT] reagent. According to cytokine analysis, different mouse strains show different cytokine patterns in response to LPS. C57BL/6 macrophages produced more IL-17, IL-10, and IFN-gamma while BALB/c macrophages produced more TGF-beta[1]., and IL-4. There was no significant difference in IDO activity between strains [p

Expression of endoderm and hepatic specific genes after in vitro differentiation of human embryonic stem cells

Human embryonic stem cells [hESC], which are derived from the inner cell mass of the blastocysts, have been considered to be pluripotent cells. In this study we examine the differentiating potential of hESC into hepatocytes by characterization of the expression of endoderm and liver-specific genes. hESC were cultivated in suspension to form aggregates, the embryoid bodies. They were allowed to outgrowth on the plated culture with the stepwise addition of growth factors such as acidic fibroblast growth factor [aFGF], hepatocyte growth factor and oncostatin M into the culture medium. The expressions of endodermal and liver specific genes such as hepatocyte nuclear factor 3 beta, alpha-fetoprotein [AFP], albumin [ALB], cytokeratin 8 [CK-8], CK-18, transthyretin, glucose 6-phosphatase and tyrosine aminotransferase were analyzed by reverse transcription-polymerase chain reaction [RT-PCR]. The expressions of ALB and CK-18 in the cytoplasm were analyzed by Immunohistochemistry. The immunoblotting and chemiluminescence of the conditioned media indicated the secretion of ALB and AFP. RT-PCR analysis revealed that hepatic gene expression related to early and late-stage liver development were enhanced through in vitro differentiation of hESC. Our results showed the expression of endoderm and hepatic specific genes after in vitro differentiation of hESC into hepatocyte-like cells through addition of various growth factors in three dimensional culture systems [collagen type I]. hESC could be a new potential source of hepatocyte for transplantation in patients with liver failure