Effects of Kupffer cell and macrophage depletion on survival of transplanted islets

Primary nonfunction(PNF)limits the success of allogeneic islet transplantation。PNF is attributed to non-specific inflammatory events occurring at the transplant site，in the liver or under the renal capsule。Methods：The liver，pancreas and isolated islets were stained using ED1 and ED2moAb on cryostat sections。Islets were isolated using collagenase digestion and the discontinuous dextran gradient method.The direct immuno-peroxydase method was performed for immunohistorologal analysis.Male Wistar rats were utilized as donors，and inbred male Lewis rats made diabetic using streptozotocin as recipients。Depletion of macrophages in isolated islets was performed by 4h co-culture with 50µL/mL LE·C12MDP。Recipient rats were pretreated with 150µL/10-g BW LE-C12MDP or saline intraperitoneal injection About1000 islets were transplanted under the renal capsule.Experimental animals were divided into four groups：Groups：Group1(n=8)，4h culture+saline pretreatment，Group2(n=8)，4h LE-C12MDP co-culture+saline pretreatment；Group3(n=8)，4h culture+LE-C12MDP pretreatment，Group4(n=8)，4h LE-C12MDP co-culture+LE-C12MDP pretreatment。Results：ED2+were barely observed(&lt；1%)in islets and pancreas。ED1+were frequently observed in.Percentages of ED1+in freshly isolated islets，cultured islets and co-cultured islets with LE-C12MDP were 11.8%，9.2%，and2.6%，respectively.LE-C12 MDP i.p.And i.v.Resulted in depletion of ED1+and ED2+in the liver，but ED1+remained in the pancreas。Incidences of PNF in Groups1.4were 62.5%，50%，50%and0%，respectively。Conclusions：1)Few tissue types of macrophage(ED2+)might exist in the pancreas and islets.2)The monocyte/macrophage lineage(ED1+)can be depleted using co-cultures of purified islets and LE-C12MDP，but not by systemic LE-C12MDP administration.3)Depletion，of the monocyte/macrophage lineage from islets and LE-C12MDP pretreatment of recipients is effective in preventing PNF of transplanted islets.

Primary nonfunction (PNF) limits the success of allogeneic islet transplantation. PNF is attributed to non-specific inflammatory events occurring at the transplant site, in the liver or under the renal capsule. Methods: The liver, pancreas and isolated islets were stained using ED1 and ED2 moAb on cryostat sections. Islets were isolated using collagenase digestion and the discontinuous dextran gradient method. The direct immuno-peroxydase method was performed for immunohistorologal analysis. Male Wistar rats were utilized as donors, and inbred male Lewis rats made diabetic using streptozotocin as recipients. Depletion of macrophages in isolated islets was performed by 4 h co-culture with 50 μ L/mL LE・C12MDP. Recipient rats were pretreated with 150 μ L/10-g BW LE-C12MDP or saline intraperitoneal injection About 1000 islets were transplanted under the renal capsule. Experimental animals were divided into four groups: Group 1(n=8), 4 h culture + saline pretreatment, Group 2(n=8), 4 h LE-C12MDP co-culture + saline pretreatment; Group 3(n=8), 4 h culture + LE-C12MDP pretreatment, Group 4(n=8), 4 h LE-C12MDP co-culture + LE-C12MDP pretreatment. Results: ED2+were barely observed (<1%) in islets and pancreas. ED1+were frequently observed in. Percentages of ED1+in freshly isolated islets, cultured islets and co-cultured islets with LE-C12MDP were 11.8%, 9.2%, and 2.6%, respectively. LE-C12MDP i.p. and i.v. resulted in depletion of ED1+and ED2+in the liver, but ED1+remained in the pancreas. Incidences of PNF in Groups 1.4 were 62.5%, 50%, 50% and 0%, respectively. Conclusions: 1) Few tissue types of macrophage (ED2+) might exist in the pancreas and islets. 2) The monocyte/macrophage lineage (ED1+) can be depleted using co-cultures of purified islets and LE-C12MDP, but not by systemic LE-C12MDP administration. 3) Depletion, of the monocyte/macrophage lineage from islets and LE-C12MDP pretreatment of recipients is effective in preventing PNF of transplanted islets.