Pipeleers D G, Pipeleers-Marichal M, Vanbrabandt B, Duys S
Department of Metabolism and Endocrinology, Vrije Universiteit Brussel, Belgium.
Diabetes. 1991 Jul;40(7):920-30. doi: 10.2337/diab.40.7.920.
This study examines whether the survival of allografted rat islet beta-cells is influenced by the presence of other pancreatic donor cells. Grafts (RT1u/l) of different cellular composition were intraportally transplanted in streptozocin-induced diabetic rats (RT1n/n). All grafts corrected the diabetic state within 3 days. Implants of freshly isolated islets contained various endocrine and nonendocrine cell types; they became diffusely infiltrated within 1 wk and were completely destroyed within 2 wk. A 4-day culture period did not lead to major changes in the cellular composition of the islets or in their survival as allograft. Islet cell aggregates prepared after islet dissociation and cell purification were less acutely infiltrated and less rapidly rejected. Aggregates composed of sorted MHC class II-negative cells maintained basal normoglycemia in 3 of 5 recipients for 5 wk but only in 1 of 5 for 20 wk. Aggregates of purified islet beta-cells remained relatively free of diffuse infiltrations during the 1st wk and preserved the normalized state in 7 of 13 recipients for 5 wk; after 20 wk, 6 of 13 were still aglucosuric, but 40% of the implants were diffusely infiltrated and depleted of insulin. Reaggregation of purified islet beta-cells with purified islet endocrine non-beta-cells promoted their long-term survival as allograft: 11 of 13 recipients of mixed islet endocrine cells maintained normal basal glycemia over 20 wk; their implants contained relatively constant insulin reserves and remained virtually devoid of diffuse infiltrations. These results demonstrate that techniques aiming at the elimination of surface MHC class II-positive cells are less successful in preparing rat islet allografts of low immunogenicity than methods of positive cell selection. Pure islet beta-cells are immunogenic as an allograft but illicit a milder and less-acute immune attack than undissociated islet tissue. Nonendocrine and damaged islet cells are suspected of enhancing the rapidity and intensity of the cytotoxic reaction. Survival of allografted beta-cells is markedly prolonged by the presence of islet endocrine non-beta-cells within the graft. The mechanisms underlying this effect have not yet been elucidated; they may involve immune and metabolic interactions of the endocrine non-beta-cells. We conclude that purification of islet endocrine cells represents a new and powerful method for preparing insulin-producing allografts that can survive in hosts without pharmacological immunosuppression.
本研究考察了同种异体移植的大鼠胰岛β细胞的存活是否受其他胰腺供体细胞的存在影响。将不同细胞组成的移植物（RT1u/l）经门静脉移植到链脲佐菌素诱导的糖尿病大鼠（RT1n/n）体内。所有移植物均在3天内纠正了糖尿病状态。新鲜分离的胰岛植入物包含各种内分泌和非内分泌细胞类型；它们在1周内出现弥漫性浸润，并在2周内被完全破坏。4天的培养期并未导致胰岛细胞组成或其作为同种异体移植物的存活出现重大变化。胰岛解离和细胞纯化后制备的胰岛细胞聚集体浸润程度较轻，排斥反应较慢。由分选的MHC II类阴性细胞组成的聚集体在5只受体中的3只中维持基础血糖正常5周，但在5只中只有1只维持20周。纯化的胰岛β细胞聚集体在第1周内相对没有弥漫性浸润，在13只受体中的7只中维持正常状态5周；20周后，13只中有6只仍无糖尿，但40%的植入物出现弥漫性浸润且胰岛素耗竭。纯化的胰岛β细胞与纯化的胰岛内分泌非β细胞重新聚集可促进其作为同种异体移植物的长期存活：13只混合胰岛内分泌细胞受体中有11只在20周内维持基础血糖正常；其植入物含有相对恒定的胰岛素储备，且几乎没有弥漫性浸润。这些结果表明，旨在消除表面MHC II类阳性细胞的技术在制备低免疫原性大鼠胰岛同种异体移植物方面不如阳性细胞选择方法成功。纯胰岛β细胞作为同种异体移植物具有免疫原性，但引发的免疫攻击比未解离的胰岛组织更温和、更不剧烈。非内分泌和受损的胰岛细胞被怀疑会增强细胞毒性反应的速度和强度。移植物中存在胰岛内分泌非β细胞可显著延长同种异体移植β细胞的存活时间。这种作用的潜在机制尚未阐明；可能涉及内分泌非β细胞的免疫和代谢相互作用。我们得出结论，胰岛内分泌细胞的纯化是一种制备能在无药物免疫抑制的宿主体内存活的胰岛素产生同种异体移植物的新的有力方法。
