Study on systemic immune tolerance induction in rat islet transplantation by intravenous infusion of Sertoli cells.

BACKGROUND: Sertoli cells are usually co-transplanted with pancreatic islets to induce local immune tolerance. In this report, we used infusion with Sertoli cells in islet transplantation to induce systemic immune tolerance and studied the mechanism of the tolerance induction. METHODS: Streptozotocin-induced diabetic rats were divided into four groups before islet transplantation: group A as control; group B with intravenous infusion of Sertoli cells; group C with Sertoli cell infusion and Fas ligand antibody treatment; and group D with Sertoli cell infusion and transforming growth factor-beta1 antibody treatment. The mean survival time (MST) and insulin expression of islet grafts were measured. The number of lymphocytes and the levels of cytokines in peripheral blood were also measured. RESULTS: Group B had the longest MST of islet allografts (41.6+/-4.20 days) followed by groups C, D, and A (P<0.05). Immunohistochemistry showed similar results with MST. The rats in group B had the least CD4 T cells (only 15.6%+/-6.4%) compared with other groups (P<0.05). The numbers of CD8 T cells in rats of groups B (11.2%+/-4.3%) and D (14.5%+/-5.6%) were significantly lower than those of groups A and C (P<0.05). After transplantation, group B's interleukin (IL)-2 level (1.92+/-0.68 ng/mL) was found to be significantly lower than that of other groups (P<0.05). Interferon-gamma showed similar pattern of change as IL-2 (P<0.05). Groups A and D had significantly lower levels of IL-4 (4.31+/-1.97 pg/mL 4.69+/-1.33 pg/mL, respectively) than groups B and C (P<0.05). CONCLUSION: Infusion of Sertoli cells could effectively prolong the survival of islet grafts and reduce peripheral blood lymphocyte and cytokine levels. In this process, transforming growth factor-beta1 played a major role and Fas ligand played a smaller additional role.

[Comparison of different isolation methods on adult Sertoli cells co-transplanted with islets].

AIM: To establish a more convenient and effective method for isolating adult Sertoli cells and apply the method to islet transplantation. METHODS: Trypsin, DNase, collagenase and hyaluronidase were used for a one-step digestion in group A. A two-step digestion was used in group B, in which testis tissues were first digested by trypsin and DNase and then were digested by collagenase and hyaluronidase. In group C, trypsin and DNase were used in the first step of digestion, hyaluronidase was used in the second step and collagenase was used in the third step. Sertoli cells were identified by morphology and immunohistochemistry and the viability and purity of Sertoli cells were detected by MTT and flow cytometry (FCM). Expression of Fas-L was detected by Western blot and the effects of the co-transplantation of islets and Sertoli cells were compared between the three groups. RESULTS: Typical Sertoli cells were seen after isolation using the three different methods. Sertoli cells isolated by method A and method B were large in number while those isolated by method B and method C were pure. The results of MTT showed that the viability of Sertoli cells in group B was significantly higher than that in group A and group C (P<0.05) and Western blot results showed that expression of Fas-L on Sertoli cells in group B was significantly stronger than that in group A and group C (P<0.05). The purity of Sertoli cells detected by FCM in group B and group C were significantly higher than that in group A (P<0.05). The survival of islets co-transplanted with Sertoli cells to renal capsule of diabetic mice was significantly longer in group B compared with that in control group as well as in group A and group C (P<0.05). CONCLUSION: Sertoli cells obtained by the two-step digestion method are of higher purity and viability, which significantly prolong the survival of islet graft by co-transplantation.

Application of kushenin on patients with chronic hepatitis C after renal transplantation.

OBJECTIVE: To evaluate the efficacy of kushenin in treating patients with chronic hepatitis C after renal transplantation. METHODS: Fifty-five patients were randomly assigned by lottery to the treatment group (29 cases) and control group (26 cases). The same immunosuppression therapy was given to all patients in both groups. Patients in the treatment group were treated with kushenin 0.6 g once a day, while those in the control group were treated with conventional liver protective agents such as vitamins. The treatment duration of both groups was 3 months. The incidences of serious hepatitis and acute rejection reaction, serum biochemistry parameters including indicators of liver and kidney functions, hepatic fibrosis index, and serum HCV-RNA were compared between the two groups. RESULTS: (1) The incidence of serious hepatitis in the treatment group and the control group was 3.45% (1/29 cases) and 11.54% (3/26 cases), respectively, which was insignificantly different between the two groups (P=0.335). (2) The incidence of acute rejection in the treatment group was 6.90% (2/29 cases) and that in the control group was 7.69% (2/26 cases), showing insignificant difference (P=0.335). (3) The differences in serum alanine aminotransferase (ALT), direct bilirubin (DBIL), hyaluronic acid (HA), propeptide collagen type III (PC III), laminin (LN), collagen type IV (Col IV) levels between the two groups were insignificant before transplantation (P>0.05), while the above-mentioned parameters in the treatment group were significantly lower than those in the control group after transplantation (P<0.05). The difference in serum creatinine (SCr) and endogenous creatinine clearance rate (CCr) between the two groups was insignificant before and after transplantation (P>0.05). (4) The negative conversion rate of HCV-RNA in the treatment group was 31.03% (9/29 cases), significantly higher than the value of 11.54% (3/26 cases) in the control group after transplantation (P<0.05). (5) The levels of serum ALT and DBIL in patients with HCV-RNA converted to negative were significantly lower than those with still-positive HCV-RNA (P<0.05). CONCLUSIONS: Kushenin has a certain effect on inhibiting the proliferation of HCV, protecting liver cells, and anti-liver fibrosis. On the other hand, it has no obvious influence on renal allograft function. Thus, the drug is clinically safe and effective for use in treating patients with chronic hepatitis C after renal transplantation.