ENDOSCOPIC BIOPSY OF ISLET TRANSPLANTS IN THE GASTRIC SUBMUCOSAL SPACE IN PIGS

描述(由申请人提供)：将已故人类供体胰岛移植(TX)到1型糖尿病患者的门静脉(PV)，取得了令人鼓舞的结果。然而，(I)出血或血栓形成的发病率很高，以及(Ii)由于一种被称为“即时血液介导的炎症反应”(IBMIR)的炎症反应，大量胰岛立即丧失(估计有60%-80%)。(Iii)无法对胰岛部位进行活组织检查，因此不能完全评估胰岛功能丧失的原因，例如急性排斥反应。胃粘膜下间隙(GSMS)提供了几个潜在的优势，我们已经在糖尿病猪胰岛TX模型中探索了这些优势。即使仅相当于PV，GSMS也在以下方面提供了优势：(I)内窥镜检查，(Ii)减少技术并发症，(Iii)潜在的活检能力。在胰岛TX进入GSM后，我们假设内窥镜活检可以提供同种异体移植排斥反应的证据，这将与血糖水平和胰岛素需求相关。这项拟议研究的具体目的是确定内窥镜下对糖尿病猪GSM中的同种异体胰岛移植物进行活检是否能够提供与临床信息(如血糖水平、胰岛素需求量)相关的组织病理学和免疫组织化学信息。这些信息将允许采取措施提高胰岛移植物的存活率(例如，增加免疫抑制治疗)和/或有利于胰岛移植物受体的管理(例如，表明需要reTx)。在链脲佐菌素(STZ)诱导的糖尿病猪接受部分(不足)(n=4)或完全(n=8)免疫抑制治疗的情况下，将MHC完全不相合的猪胰岛Tx经内窥镜送入GSMS。在胰岛TX后第14天和第28天，将通过内窥镜超声检查(EUS)、内窥镜黏膜下剥离(ESD)和活检来定位胰岛。我们相信，EUS将使胰岛肿块得到满意的定位，而ESD和活检将提供可以染色和显微镜检查的胰岛组织。这将提供有价值的组织病理学信息，有助于确定胰岛的状态和修改免疫抑制方案。这项研究将进一步证实GSMS作为胰岛TX的地点的优势，并允许考虑进行临床试验。 公共卫生相关性：本研究将探索将胰岛移植到猪的胃粘膜下间隙(GSM)中进行活组织检查的技术和成功。在这个部位，使用内窥镜超声检查，然后进行内窥镜黏膜下剥离，应该可以安全地对胰岛进行活组织检查，这将使显微镜检查能够发现排斥反应和其他病理情况。当胰岛被移植到肝脏中时，这是不可能的(目前的方法)，成功和安全地进行胰岛活组织检查的能力将允许改进免疫抑制疗法，并应证明在长期保持健康的胰岛移植方面取得了重大进展。

DESCRIPTION (provided by applicant): The allotransplantation (Tx) of deceased human donor islets into the portal vein (PV) in patients with type 1 diabetes has been followed by encouraging results. However, there is (i) a significant incidence of morbidity from hemorrhage or thrombosis, and (ii) an immediate loss of a large mass of islets (estimated at 60-80%) through an inflammatory response known as the 'instant blood-mediated inflammatory reaction' (IBMIR). (iii) Biopsy of the site of the islets is not possible, and therefore the cause of loss of islet function, e.g., acute rejection, cannot be fully assessed. The gastric submucosal space (GSMS) offers several potential advantages, which we have explored in a diabetic pig islet Tx model. Even if only equivalent to the PV, the GSMS offers advantages in the form of (i) endoscopic access, (ii) reduced technical complications, and (iii) potential ability to biopsy. After islet Tx into the GSMS, we hypothesize that endoscopic biopsy can provide evidence of allograft rejection, and this will correlate with blood glucose levels and insulin requirements. The specific aim of this proposed study is to determine whether endoscopic biopsy of islet allografts in the GSMS in diabetic pigs can provide histopathological and immunohistochemical information that correlates with clinical information (e.g., blood glucose level, insulin requirement). This information will allow steps to be taken to enhance islet graft survival (e.g., increase in immunosuppressive therapy) and/or be beneficial to the management of the islet graft recipient (e.g., indicate the need for reTx). MHC full-mismatched pig islet Tx will be performed endoscopically into the GSMS in streptozotocin (STZ)-induced diabetic pigs receiving partial (inadequate) (n=4) or full (n=8) immunosuppressive therapy. The islets will be located by endoscopic ultrasonography (EUS) followed by endoscopic submucosal dissection (ESD) and biopsy on days 14 and 28 after islet Tx. We believe that EUS will allow satisfactory localization of the islet mass, and ESD and biopsy will provide islet tissue that can be stained and examined microscopically. This will provide valuable histopathologic information of help in determining the state of the islets and in modifying the immunosuppressive regimen. This study will provide further confirmation of the advantages of the GSMS as a site for islet Tx, and allow consideration of a clinical trial. PUBLIC HEALTH RELEVANCE: This study will explore the technique and success of taking biopsies of pancreatic islets transplanted into the gastric submucosal space (GSMS) in pigs. In this site, using endoscopic ultrasonography followed by endoscopic submucosal dissection, it should prove possible to biopsy the islets safely, which will allow microscopic examination to detect rejection and other pathological conditions. As this is not possible when islets are transplanted into the liver (the current approach), the ability to carry out islet biopsies successfully and safely will allow modification of immunosuppressive therapy, and should prove a major advance in maintaining healthy islet transplants long-term - 1 -