MESENCHYMAL STEM CELLS AND CELLULAR TRANSPLANTATION

Y. Ohmura, M. Tanemura, T. Machida, T. Deguchi, H. Wada, S. Kobayashi, S. Marubashi, H. Eguchi, Y. Takeda, N. Kawaguchi, N. Matsuura, T. Ito, H. Nagano, Y. Doki, M. Mori
Department Of Surgery, Osaka University Graduate School of Medicine, Osaka/JAPAN

Body: <Introduction> Islet transplantation can provide insulin independence in the patients with type 1 diabetes. However, sufficient islets derived from two or more donors are often required to achieve insulin independence, because substantial number of transplanted islets fails to engraft into the recipient liver by the results of apoptosis, inflammation and ischemia. Moreover, shortage of donor organs spurs research into alternative means of generating β cells from stem cells, including adipose tissue-derived stem cells (ADSC). ADSC can be induced to differentiate into multiple phenotypes, including adipocytes, neurons, endothelial cells and insulin-producing cells. We hypothesized that ADSC may contain angiogenic progenitor cells and that hybrid islet transplantation based on with ADSC may promote long-term ischemic islet graft survival by remodeling the growth of vascular network. <Purpose> This study aims to demonstrate the clinical relevance of hybrid islet transplantation with marginal islet mass and ADSC. <Materials and Methods> Isolation of islets : Anesthetized male BALB/cA mice underwent pancreatic inflation using ET-Kyoto. The inflated pancreas was excited and digested by collagenase type VIII, followed by purification using a discontinuous Ficoll gradient. Isolation of ADSC : ADSC were collected from the subcutaneous adipose tissue from male C57BL/6J mice. Subcutaneous adipose tissues were digested in DMEM containing 1mg/ml of collagenase type II, and cultured. Transplantation : Streptozotocin(STZ)-induced diabetic male C57BL/6J mice were employed as recipients. The isolated islets were co-transplanted with ADSC under the kidney capsule. Transplanted mice were divided into 4 groups (A-D, 5 mice/group). Allogeneic islet transplantation groups included group A : islet alone (400 IEQ/mouse) and group B : islet alone (200 IEQ/mouse). Hybrid islet transplantation group included group C : islet (200 IEQ/mouse) + syngeneic ADSC (2x10⁵ cells/mouse) and group D : syngeneic ADSC alone (2x10⁵ cells/mouse). After transplantation, the recipients were measured the non-fasting blood glucose for everyday. The recipients were considered graft rejection when the blood glucose level was equal to 250 mg/dl. Intraperitoneal glucose tolerance test (IPGTT) : IPGTT was performed to evaluate the in vivo potency of transplanted islets at day 10. <Results> The data were summarized in the table as described below. <Conclusions> In this study, we have demonstrated that syngeneic ADSC promoted significant long-term islet allograft survival in STZ-induced diabetic mice and that the required number of islets for supporting normoglycemia was reduced to the half number of them. The protocol of hybrid islet transplantation with ADSC may open the window of opportunity to allow “one-donor to multi-recipients” islet transplantation and could have a significant clinical impact on the patients with type 1 diabetes.

Disclosure: All authors have declared no conflicts of interest.