Monitoring neovascularization of intraportal islet grafts by dynamic contrast enhanced magnetic resonance imaging.

Islets

PubMedID: 20428485

Chan NK, Obenaus A, Tan A, Sakata N, Mace J, Peverini R, Chinnock R, Sowers LC, Hathout E. Monitoring neovascularization of intraportal islet grafts by dynamic contrast enhanced magnetic resonance imaging. Islets. 2009;1(3):249-255.
Fifteen thousand youths are diagnosed yearly with type 1 diabetes mellitus. Pancreatic islet transplantation has been shown clinically to provide short-term (~1 year) insulin independence. However, challenges associated with early vascularization of transplanted islet grafts and long-term islet survival remain. We utilized dynamic contrast enhanced magnetic resonance imaging (DCE MRI) to monitor neovascularization of islets transplanted into the right lobe of the liver in a syngeneic mouse model. The left lobe received no islets and served as a control. DCE data were analyzed for temporal dynamics of contrast (gadolinium) extravasation and the results were fit to a Tofts two-compartment exchange model. We observed maximal right lobe enhancement at seven days post-transplantation. Histological examination up to 28 days was used to confirm imaging results. DCE-derived enhancement strongly correlated with immunohistochemical measures of neovascularization. To our knowledge these results are the first to demonstrate, using a FDA approved contrast agent, that DCE MRI can effectively and non-invasively monitor the progression of angiogenesis in intraportal islet grafts.