No abstract

IRB 00006477.

We sought to determine whether or not optimizing pancreas preservation, islet processing, and induction immunosuppression would facilitate sustained diabetes reversal after single-donor islet transplants. Islets were isolated from two-layer preserved pancreata, purified, cultured for 2 days; and transplanted into six C-peptide-negative, nonuremic, type 1 diabetic patients with hypoglycemia unawareness. Induction immunosuppression, which began 2 days pretransplant, included the Fc receptor nonbinding humanized anti-CD3 monoclonal antibody hOKT3c 1 (AlaAla) and sirolimus. Immunosuppression was maintained with sirolimus and reduced-dose tacrolimus. Of our six recipients, four achieved and maintained insulin independence with normal HbA1c levels and freedom from hypoglycemia; one had partial islet graft function; and one lost islet graft function 2 weeks post-transplant. The four insulin-independent patients showed prolonged CD4 + T-cell lymphocytopenia; inverted CD4:CD8 ratios; and increases in the percentage of CD4 + CD25 + T cells. These cells suppressed the in-vitro proliferative response to donor cells and, to a lesser extent, to third-party cells. Severe adverse events were limited to a transient rash in one recipient and to temporary neutropenia in three. Our preliminary results thus suggest that a combination of maximized viable islet yield, pretransplant islet culture, and preemptive immunosuppression can result in successful single-donor islet transplants.

No abstract

Pancreatic islet transplantation may successfully restore normoglycemia in type 1 diabetic patients. However, successful grafting requires transplantation of a sufficient number of islets, usually requiring two or more donors. During the isolation process and following clinical transplantation, islets are subjected to severe adverse conditions that impair survival and ultimately contribute to graft failure. Here, we have mapped the major intracellular stress-signaling pathways that may mediate human islet loss during isolation and following cytokine attack. We found that the isolation procedure potently recruits two pathways consisting of ͦmitogen-activated protein kinase kinase (MKK)7 3 Jun NH 2 -terminal kinase (JNK)/p38 3 c-fosͦ and the ͦnuclear factor-B (NF-B) 3 iNOSͦ module. Cytokines activate the ͦNF-B 3 iNOSͦ and ͦMKK4/MKK3/6 3 JNK/p38ͦ pathways without recruitment of c-fos. Culturing the islets for 48 h after isolation allows for the activated pathways to return to background levels, with expression of MKK7 becoming undetectable. These data indicate that isolation and cytokines recruit different death pathways. Therefore, strategies might be rationally developed to avoid possible synergistic activation of these pathways in mediating islet loss during isolation and following grafting.