Poor efficacy is one of the issues for clinical islet transplantation. Recently, we demonstrated that pancreatic ductal preservation significantly improved the success rate of islet isolation; however, two transplants were necessary to achieve insulin independence. In this study, we introduced iodixanol-based purification, thymoglobulin induction, and double blockage of IL-1β and TNF-α as well as sirolimus-free immunosuppression to improve the efficacy of clinical islet transplantation. Nine clinical-grade human pancreata were procured. Pancreatic ductal preservation was performed using ET-Kyoto solution in all cases. When the isolated islets met the clinical criteria, they were transplanted. We utilized two methods of immunosuppression and antiinflammation. The first protocol prescribed daclizumab for induction, then sirolimus and tacrolimus to maintain immunosuppression. The second protocol used thymoglobulin for induction and tacrolimus and mycophenolate mofetil to maintain immunosuppression. Eternacept and anakinra were administered as anti-inflammatory drugs. The total amount of insulin required, HbA1c, and the SUITO index were determined to analyze and compare the results of transplantation. All isolated islet preparations (9/9) met the criteria for clinical transplantation, and they were transplanted into six type 1 diabetic patients. All patients achieved insulin independence with normal HbA1c levels; however, the first protocol required two islet infusions (N = 3) and the second protocol only required a single infusion (N = 3). The average SUITO index, at 1 month after a single-donor islet transplantation, was significantly higher in the second protocol (49.6 ± 8.3 vs. 19.3 ± 6.3, p < 0.05). Pancreatic ductal preservation, iodixanol-based purification combined with thymoglobulin induction, and blockage of IL-1β and TNF-α as well as sirolimus-free immunosuppression dramatically improved the efficacy of clinical islet transplantations. This protocol enabled us to perform successful single-donor islet transplantations. Further large-scale studies are necessary to confirm these results and clarify the mechanism of each component.
Purpose: It has been shown that a lymphatic differentiation master gene, prox1, also plays an essential role in fetal hepatocyte migration. Its expression is detected in embryonic hepatoblasts and in adult hepatocytes. Hepatoma cells are similar to embryonic hepatoblasts to a certain extent because they both proliferate and invade the surrounding tissue. To address the possibility that Prox1 may be involved in the tumorigenesis of hepatocellular carcinoma (HCC), human clinical samples were analyzed. Experimental Design: To screen prox1 as a potential tumor suppressor gene, its expression was analyzed in HCC cell lines and in human HCC tissues. Its growth-conferring abilities were assessed by transiently overexpressing Prox1in HCC cell lines and by knocking down its expression by RNA interference. Results: We found that there was a significant correlation between Prox1 expression and the differentiation scores of the tumors. Subsequently, we also showed that low expression of Prox1 in tumors was closely associated with a poor prognosis.The specific knockdown of Prox1by RNA interference strongly accelerated in vitro cell growth, whereas the overexpression of Prox1greatly suppressed the growth. Conclusions: Our results suggest that Prox1is involved in the differentiation and progression of HCC, and thus it may be a candidate for the development of novel diagnostic and therapeutic strategies for HCC.
Our data suggest that using an iodixanol-controlled density gradient improves the islet recovery rate in human islet isolation. On the basis of these data, we now use this purification method for clinical islet transplantation.
Inconsistent islet isolation is one of the issues of clinical islet transplantation. In the current study, we applied ductal injection to improve the consistency of islet isolation. Seven islet isolations were performed with the ductal injection of ET-Kyoto solution (DI group) and eight islet isolations were performed without the ductal injection (standard group) using brain-dead donor pancreata. Isolated islets were evaluated based on the Edmonton protocol for transplantation. The DI group had significantly higher islet yields (588,566 ± 64,319 vs. 354,836 ± 89,649 IE, p < 0.01) and viability (97.3 ± 1.2% vs. 92.6 ± 1.2%, p < 0.02) compared with the standard group. All seven isolated islet preparations in the DI group (100%), versus only three out of eight isolated islet preparations (38%) in the standard group met transplantation criteria. The islets from the DI group were transplanted into three type 1 diabetic patients and all three patients became insulin independent. Ductal injection significantly improved quantity and quality of isolated islets and resulted in high success rate of clinical islet transplantation. This simple modification will reduce the risk of failure of clinical islet isolation.
Functional pancreatic β-cells were generated from human iPSCs. Induction of definitive endoderm and spheroid formation may be key steps for producing these cells.
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