No abstract

We have previously demonstrated that coculture of islets with mesenchymal stromal cells (MSCs) enhanced islet insulin secretory capacity in vitro, correlating with improved graft function in vivo. To identify factors that contribute to MSC-mediated improvements in islet function, we have used an unbiased quantitative RT-PCR screening approach to identify MSC-derived peptide ligands of G-protein-coupled receptors that are expressed by islets cells. We demonstrated high expression of annexin A1 (ANXA1) mRNA by MSCs and confirmed expression at the protein level in lysates and MSCconditioned media by Western blot analysis and ELISA. Preculturing islets with exogenous ANXA1 enhanced glucose-stimulated insulin secretion (GSIS), thereby mimicking the beneficial influence of MSC preculture in vitro. Small interfering RNA-mediated knockdown of ANXA1 in MSCs reduced their capacity to potentiate GSIS. MSCs derived from ANXA1 2/2 mice had no functional capacity to enhance GSIS, in contrast to wild-type controls. Preculturing islets with ANXA1 had modest effects on their capacity to regulate blood glucose in streptozotocininduced diabetic mice, indicating that additional MSCderived factors are required to fully mimic the beneficial effects of MSC preculture in vivo. These findings demonstrate the feasibility of harnessing the MSC secretome as a defined, noncellular strategy to improve the efficiency of clinical islet transplantation protocols.There is a growing body of evidence that mesenchymal stromal cells (MSCs) can enhance the functional survival of islet grafts after transplantation, offering a potential therapeutic method for improving the outcomes of islet transplantation as a therapy for type 1 diabetes. A number of MSC-derived trophic factors have been shown to influence the graft niche by modifying the responses of host immune, endothelial, or progenitor cells to reduce inflammatory or immune responses (1,2) and to improve graft revascularization (3-5). However, we (6-8) and others (4,9-11) have demonstrated that MSCs also have direct effects on donor islet cells to improve their survival and secretory function. Thus, we previously used direct contact coculture of islets with MSCs derived from kidney (6) or adipose tissue (7) to enhance glucose-stimulated insulin secretion (GSIS) in vitro and demonstrated that this results in superior in vivo function for islet-alone grafts at the experimental renal subcapsular (6) and clinically preferred intraportal transplantation site (7). Previous studies suggest that the beneficial effect of MSCs on islet function is at least partly mediated by soluble bioactive molecules (12), so we have now applied a nonbiased screening approach to identify novel MSCderived secretory products that may influence islet function. We have based the current screen on our recent demonstration that islets express 293 different G-proteincoupled receptors (GPCRs) that are known to be activated by more than 250 identified ligands (13). In this study, we have used a quantitative (q)RT-PCR approach to ...

The findings indicate that increased IL-10, -8 and -6 levels may constitute an early predictor of unfavourable outcome in severe TBI patients.

A sample of 103 randomly chosen healthy individuals from Alegrete, RS, Brazil, was tested for the CCR5∆32 allele, which is known to influence susceptibility to HIV-1 infection. The CCR5∆32 allele was identified by PCR amplification using specific primers flanking the region of deletion, followed by electrophoresis on a 3% agarose gel. The data obtained were compared to those reported for other populations and interpreted in terms of Brazilian history. The individuals studied came from a highly admixed population. Most of them were identified as white (N = 59), while blacks and browns (mulattoes) were N = 13 and N = 31, respectively. The observed frequencies, considering the white, black and brown samples (6.8, 3.8, and 6.4%, respectively), suggest an important European parental contribution, even in populations identified as black and brown. However, in Brazil as a whole, this allele shows gradients indicating a relatively good correlation with the classification based on skin color and other physical traits, used here to define major Brazilian population groups. Correspondence

Sickle cell disease (SCD) is an inherited disorder that presents extremely variable clinical manifestations. For the past few decades, it has been approached as an inflammatory disorder, and several researchers have tried to determine the factors involved in such characteristic. In order to contribute to the identification of the genetic differences underlying this phenotypic diversity in SCD, we proposed to study the distribution of polymorphic variants of the genes encoding the chemokine receptors CCR2 and CCR5, as well as three polymorphisms in the NOS3 gene, in Brazilian SCD patients. These genes are involved in the development of inflammatory immune reactions, a feature believed to be of extreme importance in SCD pathology. Our results indicate that the polymorphisms studied here are not directly associated with severe clinical manifestations in SCD patients. Nevertheless, we observed a tendency for the development of a severe clinical course in carriers of the variant alleles CCR2-64I and CCR5delta32 and in homozygotes for the -786C variant of the NOS3 gene. Further studies should be carried out in order to assess the role of such variants in the clinical picture of SCD.