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Presenter: A., Langlois, Strasbourg, France
Authors: A. Langlois, C. Dollinger, W. Bietiger, K. Vivot, N. Jeandidier, M. Pinget, S. Sigrist
Role of islet culture on angiogenic and inflammatory mechanisms
A. Langlois1, C. Dollinger1, W. Bietiger1, K. Vivot1, N. Jeandidier2, M. Pinget2, S. Sigrist1
1 Centre européen d'étude du Diabète, Strasbourg, France; 2 Service d'endocrinologie, diabète, maladies métaboliques, Pôle NUDE, Hôpitaux Universitaires de Strasbourg, Université de Strasbourg, Strasbourg, France
Objective: Deleterious events for islet engraftment are related to IBMIR and to insufficient islets revascularisation inducing β cells death. Influence of culture duration on cellular mechanisms involved on islets revascularization and IBMIR are not well understood. The aim of this work was to study the role of islet culture on angiogenesis and inflammatory reactions in vitro
Methods: Rats islets were cultured for 0, 12, 24 and 48h. Identification of signaling pathways involved in angiogenesis and IBMIR was performed by PCR array; 84 genes were analyzed using the RT ² Profiler PCR Array Data Analysis Template v3.2. Insulin expression was evaluated using qPCR. The comparative study of gene expression was assessed toward t=0h (n= 3).
Results: After 12h of culture, islets exhibited a significant decrease in gene expression of growth factors (IGF1:-18.42) and, the kdr (VEGF receptor;-5.65 fold) (p <0, 001), this being maintained for 48 hours. No significant modulation of VEGF A, B and C expression was observed. At 12h Metallopeptidase 9 (MMP9) and its inhibitor, TIMP1 were respectively overexpressed 16.1 and 55.01 times (p <0.001). This unfavorable environment for angiogenesis was confirmed at 48 h, MMP9 expression being stable in contrast to TIMP1 (20.3 times, p <0.01). After 12h, islets had a significant overexpression of proinflammatory cytokine such as IL-6 and CXCL1 with respectively 597.9 (p <0.001) and 429.2 fold (p <0, 05). This overexpression of cytokines decreased after 12h. Concomitantly, the insulin expression decreased after 12h with 0.68 ± 0.323 fold overexpression after 24h versus 2.059 ± 0.597 fold after 12h (p< 0,05).
Conclusions: This study showed that current conditions of culture are deleterious for angiogenesis due to different mechanisms, and thus to a good implantation of islets after transplantation. These results may help finding different ways of islets protection, if they are confirmed by proteomic data.
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