一种小鼠胰岛经门静脉肝内移植方法及疗效评价

目的 介绍一种糖尿病小鼠经门静脉到肝内胰岛移植的方法并进行移植前后的血糖、口服糖耐量、免疫组化等评价。方法 采用Balb/c小鼠,将分离纯化的小鼠胰岛培养6 h后,用自制的移植工具进行糖尿病模型小鼠的肝门静脉插管和输注胰岛,移植胰岛量为（320±30）IEQ,对移植前后的小鼠血糖进行测定,在移植后第10天进行糖耐量试验,并取受体小鼠肝脏,进行HE染色和免疫组化分析,观察胰岛细胞团在肝内的存活情况。结果受体小鼠胰岛移植后血糖均能长期维持正常,糖耐量试验结果显示与正常小鼠无统计学差异（P =0.81）,组织学结果显示胰岛细胞在小鼠肝内存活良好。结论 采用本方法可建立小鼠胰岛经门静脉移植到肝内的模型,为下一步进行胰岛移植相关药物筛选及免疫学等方面研究奠定了基础。     

小鼠腹股沟皮下脂肪组织与肾被膜部位移植胰岛降血糖功能的比较

目的比较腹股沟皮下白色脂肪组织与肾被膜下移植胰岛治疗小鼠1型糖尿病的效果。方法将1型糖尿病模型小鼠分为白色脂肪组(10只)和肾被膜组(10只)接受胰岛移植。胰岛分离和纯化后,分别移植到腹股沟皮下白色脂肪组织和肾被膜下位点。术后持续监测两组受体小鼠的随机血糖水平、糖耐量功能,移植后100 d摘取两组存活受体小鼠的胰岛移植物进行组织病理学检查。结果白色脂肪组有6只受体小鼠的血糖在移植后1个月恢复正常水平,其余4只受体小鼠一直维持着高血糖状态,陆续在监测结束前发生死亡;肾被膜组10只受体小鼠的血糖均在移植后10 d内恢复正常。白色脂肪组和肾被膜组受体小鼠的胰岛移植物均能降低血糖水平,但白色脂肪组胰岛移植物需要较长的时间方能发挥降血糖功能。肾被膜组小鼠的糖耐量功能优于白色脂肪组小鼠(P0.05)。组织病理学检查显示白色脂肪组和肾被膜组胰岛移植物的胰岛素表达均正常。结论腹股沟皮下白色脂肪组织部位移植胰岛能有效地发挥调控血糖变化的功能,尽管其降血糖功能稍弱于肾被膜下部位,但具有贴近理想胰岛移植位点的众多优势,是一个值得研究的胰岛移植替代部位。     

输注胰岛抗原特异性Treg细胞延长同系NOD小鼠移植胰岛的存活时间

目的 探讨输注胰岛抗原特异性调节性T淋巴细胞(Treg细胞)对非肥胖糖尿病(NOD)小鼠同系胰岛移植物存活时间的影响.方法·以未成熟树突状细胞(imDC)联合谷氨酸脱羧酶-65在体外诱导童贞T淋巴细胞分化成胰岛抗原特异性Treg细胞.以已发生糖尿病的NOD小鼠为受者,将分离得到的尚未进展为糖尿病的NOD小鼠的胰岛(500胰岛当量)移植至受者的肾包膜下,对照组不行移植,只观察血糖变化;单纯胰岛移植组只进行胰岛移植,不输注胰岛抗原特异性Treg细胞;实验组于术前1d静脉输注1×106个胰岛抗原特异性Treg细胞,然后进行胰岛移植.术后检测受者的血糖,以判断移植胰岛的存活时间,观察胰岛移植物的病理学变化.结果 对照组血糖持续高于11.1 mmol/L;单纯胰岛移植组小鼠的血糖于术后1～2 d降至正常,到7～17d时开始陆续升高,并维持在术前水平,移植物存活时间为(12.2±2.6)d;实验组小鼠的血糖于术后1～2 d降至正常,至第27天开始有小鼠血糖升高超过11.1 mmol/L,第43天时,所有小鼠的血糖均超过11.1mmol/L,移植物的存活时间为(35.2±4.3)d,明显长于单纯胰岛移植组(P＜0.01).单纯胰岛移植组的移植胰岛有明显的淋巴细胞浸润,并伴有胰岛细胞严重破坏,胰岛素染色未见完整的胰岛存在,仅有极少量残存的分泌胰岛素的胰岛细胞;实验组第15天时移植胰岛形态完整,仅有少量淋巴细胞浸润,分泌胰岛素的胰岛大量存在.结论 体外诱导产生的胰岛抗原特异性Treg细胞可以延缓自身免疫系统对移植胰岛的破坏,明显延长NOD小鼠移植胰岛的存活时间.     

肝星状细胞对同种异体胰岛移植物的保护作用

目的 研究小鼠肝星状细胞对同种异体胰岛移植物的保护作用.方法 将糖尿病小鼠随机分为三组,分别为糖尿病组、单纯胰岛移植组及与肝星状细胞共同移植组.单纯移植组于肾被膜下移植入同种异体胰岛300个;共同移植组移植入肝星状细胞(3×105个)与同种异体胰岛(300个)混合物.分别于移植术后监测受体小鼠血糖值及正常血糖维持时间;血糖正常一周后移植组及糖尿病组小鼠分别采血检测血清中TGF-β,TNF-α,IL-1β,IFN-γ的含量,同时取出移植物进行免疫组织化学检测.结果 术后共同移植组受体正常血糖维持时间为(23.75±8.96)d,单纯胰岛移植组受体正常血糖维持时间为(11.9±6.92)d,差异有统计学意义(P<0.05);三组受体血清中TNF-α、IL-1β、IFN-γ含量差异无统计学意义(P>0.05),共同移植组受体血清中TGF-β含量为(2292.31±5.87)pg/ml,单纯移植组为(1246.55±38.91)pg/ml,两组比较差异有统计学意义(P<0.05);病理学结果显示共同移植组胰岛素表达量大,并且在移植物周围有生物包膜形成.结论 在同种异体移植模型中,肝星状细胞可能通过高分泌TGF-β、局部形成包囊等方式保护胰岛移植物并延长其存活时间.     

激活型Akt1转染大鼠胰岛联合免疫抑制剂在异种胰岛移植中的应用

目的 探讨腺病毒载体介导激活性Akt1基因(Adv-CA-Akt1)转染大鼠胰岛对异种移植胰岛功能和存活的影响.方法 以BALB/C糖尿病小鼠为受体,分离纯化雄性Wistar大鼠胰岛,体外培养,Adv-CA-Akt1转染后异种胰岛移植.受体小鼠分3组,实验组:Adv-CA-Akt1转染的大鼠胰岛体外培养24 h,小鼠肾被膜下移植,并口服环孢素A(CsA)30 mg·kg-1·d-1;CsA组:未转染胰岛移植,同剂量环孢素口服;对照组:单纯胰岛移植.每只接受300胰岛当量(IEQs)移植.检测术后血糖,移植物存活时间及组织病理学.结果 实验组和CsA组术后2 d血糖即降至正常,胰岛功能存活时间分别为(21.0±3.65)d和(9.0±2.54)d,而对照组血糖短暂下降后再次升高,胰岛功能存活时间(4.2±2.6)d.实验组小鼠生存时间为(31.0±5.67)d比CsA组(17.0±3.35)d和对照组(10.0±1.52)d明显延长,三组比较差异有统计学意义(P<0.05);胰岛素免疫组化染色实验组.肾被膜下见较多有功能胰岛细胞团,而CsA组和对照组胰岛素染色阳性细胞数减少.结论 Adv-CA-Akt1转染大鼠胰岛联合应用免疫抑制剂,可提高胰岛功能,延长异种胰岛移植物存活时间.     

体外转染可溶性IL-1RI-Ig基因延长糖尿病小鼠移植胰岛细胞存活时间

目的 探讨糖尿病小鼠移植经可溶性白细胞介素1(IL-1)受体胞外段Fc融合蛋白(sIL-1RI-Ig)基因修饰的胰岛细胞对延长移植物存活时间的作用及机制.方法 将Ad-sIL-1RI-Ig体外转染Balb/c小鼠的胰岛细胞,并将其移植给糖尿病C57BL/6小鼠,观察移植物的存活时间,并检测移植局部组织炎症细胞的浸润以及炎症细胞因子的表达.结果 糖尿病小鼠移植转染sIL-1RI-Ig基因的胰岛细胞后,血糖水平很快下降至正常范围,胰岛移植物存活时间达(39±3)d,而移植正常胰岛细胞的小鼠胰岛移植物存活时间为(9±2)d(P<0.01).糖尿病小鼠移植转染sIL-1RI-Ig基因的胰岛细胞后,胰岛素分泌量随糖负荷增加而升高,并与胰岛素分泌功能正常的小鼠呈相似变化趋势(P>0.05).糖尿病小鼠移植转染sIL-1RI-Ig基因的胰岛细胞后,移植局部组织表达肿瘤坏死因子α(TNF-α)、γ干扰素(IFN-γ)和RANTES等水平明显下调;病理学观察发现移植局部组织浸润的炎症细胞明显少于移植正常胰岛细胞的小鼠.结论 sIL-1RI-Ig基因转染胰岛细胞后,可通过表达sIL-1RI-Ig,阻断IL-1的作用,降低TNF-α、IFN-γ、RANTES等细胞因子的表达,从而减轻排斥反应,延长胰岛细胞移植物的存活时间和提高胰岛素分泌功能.     

肝细胞和脾细胞单独或联合输注对异种胰岛细胞移植排斥反应的影响

目的 探讨供者的肝细胞和脾细胞输注对同一供者胰岛细胞移植排斥反应的影响。方法 经尿静脉给BALB/c小鼠糖尿病模型注射供者（猪）的肝细胞和脾细胞，腹腔内注射途径进行猪胰岛细胞移植。移植后测定受者的血糖变化，观察小鼠移植物有功能存活时间。同时测定小鼠巨噬细胞吞噬功能，脾脏淋巴细胞转化功能和自然杀伤细胞活性的变化。结果 胰岛细胞移植前输注肝细胞，脾细胞以及肝细胞和脾细胞混合悬液者，移植物有功能存活时间延长，其淋巴细胞转化率。自然杀伤细胞活性及巨噬细胞的吞噬功能均较低，以肝细胞和脾细胞联合输注者为著。结论 移植前少量多次的供者肝细胞和脾细胞输注可以降低异种胰岛细胞移植排斥反应的强度。     

小鼠异体Sertoli细胞诱导胰岛移植免疫耐受的作用

目的 观察小鼠Sertoli细胞是否能在异体内起到诱导局部免疫耐受、保护共移植异体胰岛的作用.方法 以糖尿病C57小鼠作移植受体,随机分4组,每组6只;以正常BALB/C小鼠为胰岛供体,正常C57小鼠和正常BALB/C小鼠各作为Serloli细胞供体.A组:单纯移植异体胰岛;B组:移植来源于C57小鼠的Sertoli细胞+BALB/C小鼠来源的胰岛;C组:移植均来源于BALB/C小鼠的Sertoli细胞及胰岛;D组:假手术组.监测各组移植受体的血糖尿糖变化,观察移植物的存活时间.结果 A组移植物平均存活时间为(6.50±2.35)d;B组为(55.67±4.84)d;C组为(51.33±5.05)d;D组未观察到血糖正常.B组及C组的移植方式均可逆转糖尿病小鼠的高血糖状态,移植物存活期均较A组有明显延长,其差异有统计学意义(P<0.05);而B组与C组的移植物存活时间差异无统计学意义(P>0.05).结论 同种异体来源的睾丸Sertoli细胞在异体内可起到诱导局部免疫耐受的效果,对共移植同种异体胰岛起到保护作用,其效果与自体睾丸Sertoli细胞相当.     

小鼠自体胰岛肌肉移植及疗效评价

目的探讨小鼠自体胰腺部分切除及自体胰岛的肌肉移植方法,并对术后小鼠进行疗效评价。方法选用C57BL/6小鼠,分为三组,胰腺部分切除后移植组为麻醉后切除十二指肠部沿胃大弯至脾部位的胰腺组织,并将胰岛纯化后移植至自体肌肉组织;以切除部分胰腺后未移植组和正常组作对照。结果小鼠自体胰腺部分切除和自体胰岛肌肉移植术后存活率较高,但在饲养过程中均出现持续体重下降和血糖不稳定,OGTT显示两组术后小鼠20、40 min的血糖均较正常组高,肌肉移植7 d后HE染色显示胰岛在肌肉中存活,但胰岛中心部位细胞有坏死。结论本研究建立了一种无免疫排斥下研究小鼠胰岛移植的方法,可为进一步探索改进胰岛移植研究提供参考。     

裸鼠糖尿病模型的建立及皮下异种胰岛移植研究

目的 探讨链脲左菌素（STZ）建立BALB/c nu/nu裸鼠Ⅰ型糖尿病模型的方法,及将大鼠胰岛分离纯化后移植至糖尿病裸鼠皮下,对移植后裸鼠进行疗效评价。方法 选用Balb/c裸鼠分为三组：糖尿病且胰岛移植组、糖尿病胰岛未移植组和正常组;用STZ对裸鼠进行糖尿病建模,大鼠胰岛分离、纯化后移植至糖尿病裸鼠背部皮下,进行血糖、体重和HE染色考察,以糖尿病未移植组和正常组作对照。结果 STZ浓度175 mg/kg时,腹腔注射裸鼠糖尿病造模成功率高,纯化的大鼠胰岛活性较好,但移植后疗效平均维持时间约5 d,移植第5 d的OGTT结果显示胰岛皮下移植组和糖尿病组血糖均较正常组高,移植3 d时HE染色显示胰岛在皮下存活,但胰岛中心部位细胞有坏死。结论 本研究建立了一种免疫排斥缺陷宿主异种胰岛皮下移植治疗糖尿病的方法,为进一步探索改进胰岛移植研究提供参考。     

Insulin independence of unstable diabetic patient after single living donor islet transplantation

BACKGROUND: Current success in islet transplantation will lead to a donor shortage. Living donor islet transplantation could be an alternative approach to expand the potential donor pool. In this study we describe the first successful living donor islet transplantation for unstable diabetes, performed at Kyoto University Hospital on January 19, 2005. METHODS: The donor was a healthy 56-year-old woman and mother of the recipient. The recipient was a 27-year-old woman with insulin-dependent diabetes since the age of 15 years. She experienced frequent hypoglycemic unawareness episodes. Her blood glucose concentration was difficult to control and C-peptide level was negative after glucagon stimulation. She needed an average 28 of units of insulin per day. The donor underwent a distal pancreatectomy and islets were isolated from the resected pancreas graft. The total islet yield was 408,114 islet equivalents and isolated islets were immediately transplanted into the recipient's liver. RESULTS: After transplant, the blood glucose level of the recipient was tightly controlled without hypoglycemic episodes. She was discharged on day 37 with a normal oral glucose tolerance test (OGTT). The recipient remained insulin-independent for >3 months, since day 22 posttransplant. The donor's postoperative clinical course was uneventful. She was discharged on postoperative day 18 and returned to her job within 1 month. CONCLUSIONS: We report the first successful living donor islet transplantation for the treatment of unstable diabetes. We believe that living donor islet transplantation may become an option in the treatment of insulin-dependent diabetes.     

In vitro and in vivo improvement of islet survival following treatment with nerve growth factor

BACKGROUND: Nerve growth factor (NGF) has been reported to play an important regulatory role in pancreatic beta-cell function. However, the usefulness of NGF in a transplantation setting is unknown. METHODS: A marginal number of islet cells (260 islet equivalents/recipient) cultured for 24 hr with NGF (500 ng/ml) was syngeneically transplanted under the kidney capsule of streptozotocin-induced diabetic Balb/c mice. Fluorescence microscopy was used to evaluate islet viability. Islet function was evaluated in vitro and in vivo by static assay and glucose tolerance test, respectively. RESULTS: In vitro, improved viability and survival were found in murine islets cultured in serum-free medium for 96 hr with 500 ng/ml NGF (P<0.05). NGF-treated islets had more insulin secretion than islets cultured without NGF in response to 2.8 mmol/L glucose (P<0.05), and 20 mmol/L glucose conditions. In vivo, 67% of recipients with a submarginal number of islets cultured in NGF attained normoglycemia for more than 120 days, whereas transplanted islets without NGF treatment survived a maximum of 13 days in control mice. At posttransplant day 4, recipients of NGF-cultured islets showed significant improvement of glucose tolerance. On immunohistochemistry, the kidney capsules containing NGF-cultured islets displayed higher insulin content, and more dilated neoplastic microvessels than control renal capsules. The number of apoptotic cells using TUNEL staining decreased by nearly 50% in NGF-cultured islet grafts in comparison to control islet grafts. CONCLUSIONS: The above data suggest potential advantages of NGF for islet survival following transplantation. This neurotrophic approach may prove beneficial in human islet transplantation.     

Insulin-induced normoglycemia reduces islet number needed to achieve normoglycemia after allogeneic islet transplantation in diabetic mice

The Edmonton protocol established that insulin independence could be reached with the transplantation of an appropriate number of islet cells. However, to effect a cure, islets from two or three pancreases are needed. The aim of this study was to examine whether normoglycemia, with insulin treatment before and after transplantation, reduces the islet number needed to achieve normoglycemia in allogeneic islet transplantation. Swiss mice were used as donors and recipients. Diabetes was induced by i.p. administration of streptozotocin (180 mg/kg BW). Diabetic mice were transplanted with 300 (n = 16), 400 (n = 16), or 500 (n = 16) islets under the left kidney capsule. For every group, half the animals were kept normoglycemic with insulin treatment from day 4 before transplantation to day 10 after transplantation. At the end of the study, all normoglycemic mice were given an i.p. glucose tolerance test (IPGTT). For statistical analysis, paired or unpaired Student's t-test or ANOVA was used. Only insulin-treated mice achieved normoglycemia by the end of the study (37.5% of animals transplanted with 400 islets and 50% transplanted with 300 or 500 islets). At the end of the study, normoglycemic mice transplanted with 300 allogeneic islets showed better glycosylated hemoglobin (HbA1C) than did normoglycemic mice transplanted with 500 islets (300 islets: 2.7 +/- 0.2%; 500 islets: 3.6 +/- 0.2%; p < 0.05). After the IPGTT, insulin-treated mice transplanted with 500 islets showed abnormal glucose tolerance; however, insulin-treated mice transplanted with 300 or 400 islets showed normal glucose tolerance. Insulin treatment reduced the islet number needed to achieve normoglycemia in allogeneic islet transplantation. The HbA1C and IPGTT results suggest that transplanting smaller numbers of allogeneic islets improves beta-cell function; some studies suggest that this may be due to lower immunogenicity, hypoxia, and inflammation.     

Identification of in vitro parameters predictive of graft function: a study in an animal model of islet transplantation

The quality of human islets is one of the factors decisive for the success of human islet transplantation. Several parameters have been proposed to characterize islet quality, but none of them has been able to predict the fate of a transplant. The aim of our study was to correlate a panel of in vitro parameters for islet viability with their in vivo function after transplantation in nude mice. Islets were obtained after enzymatic digestion of a human pancreas; they were purified from exocrine tissue using a continuous-density gradient. Two aliquots of islets (1000 and 2000 islets) were transplanted under the kidney capsule of diabetic nude mice. The animals were followed for 1 month with repeated measurements of blood glucose and body weight. One month after transplantation, mice were killed and their graft harvested for histologic analysis. In parallel we studied in vitro islet viability with propidium iodide and fura-2, their insulin content, their purity, and their insulin response to glucose upon static incubation. Ten islet preparations were transplanted: 3 out of 10 preparations did not restore normoglycemia; 4 out of 10 normalized glycemia only in mice receiving 2000 islets, and 3 out of 10 fully restore normoglycemia in all mice. The purity of preparations (R(2) = 0.63 and 0.85, respectively, with 1000 and 2000 islets) and the insulin content (R(2) = 0.75 with 2000 IE) correlated with transplant success. These data show that purity of islet preparations and their insulin content should be useful parameters for the selection of islet preparations for transplant purposes.     

脂肪间充质干细胞与胰岛联合移植对术后免疫状态及移植效果的影响

目的研究同系脂肪间充质干细胞(AMSC)与同种异体胰岛联合移植对胰岛移植术后免疫状态及移植效果的影响。 方法选择Lewis大鼠建立链脲佐菌素诱导的糖尿病大鼠模型作为胰岛移植受体,AMSC＋胰岛移植组经左肾包膜下联合移植Lewis大鼠AMSC及Wistar大鼠胰岛,单纯胰岛移植组经左肾包膜下单独移植Wistar大鼠胰岛,单纯AMSC移植组经左肾包膜下单独移植Lewis大鼠AMSC,阳性对照组为未进行移植的Lewis糖尿病大鼠,阴性对照组为正常Lewis大鼠。ELISA法检测血清细胞因子IFN-γ、IL-2、IL-4和IL-10浓度,流式细胞技术检测外周血CD4^＋、CD8^＋ T细胞比例,HE染色观察移植胰岛淋巴细胞浸润情况,观察血糖、胰岛素水平及胰岛移植物存活时间。采用单因素方差分析比较5组大鼠外周血淋巴细胞亚群比例和血清细胞因子水平,采用LSD法进行组间两两比较;血糖及血清胰岛素变化采用重复测量资料方差分析;采用独立样本t检验比较AMSC＋胰岛移植组与单纯胰岛移植组胰岛移植物淋巴细胞计数。采用Kaplan-Meier法绘制AMSC＋胰岛移植组与单纯胰岛移植组胰岛移植物生存曲线,并采用log-rank检验进行比较。P<0.05为差异有统计学意义。 结果AMSC＋胰岛移植组胰岛移植物平均生存时间为(26.8±3.0) d,长于单纯胰岛移植组的(19.0±1.3) d,两组大鼠胰岛移植物生存曲线差异有统计学意义(χ²＝4.494,P<0.05)。胰岛移植后各时间点,AMSC＋胰岛移植组大鼠移植后血糖和胰岛素水平均优于单纯胰岛移植组(P均<0.05)。胰岛移植前,5组大鼠外周血CD4^＋、CD8^＋ T细胞比例以及细胞因子IFN-γ、IL-2、IL-4和IL-10差异均无统计学意义(F＝0.425、0.476、0.256、0.418、0.281和0.313,P均>0.05)。胰岛移植后第7、14、28天,AMSC＋胰岛移植组大鼠外周血CD4^＋、CD8^＋T细胞比例均低于单纯胰岛移植组(P均<0.05),血清IFN-γ和IL-2浓度均低于单纯胰岛移植组(P均<0.05),IL-4和IL-10浓度均高于单纯胰岛移植组(P均<0.05)。胰岛移植第7天,AMSC＋胰岛移植组胰岛移植物平均淋巴细胞计数为(142±21)个/mm²,低于单纯胰岛移植组的(311±36)个/mm²(t＝8.245,P<0.05)。 结论与胰岛联合移植的AMSC能够提高胰岛移植的效果,可调节糖尿病大鼠体内IFN-γ、IL-2、IL-4和IL-10表达及抑制同种异体胰岛刺激的T细胞增殖,减轻胰岛移植物的免疫损伤。     

Decreased vascular density in mouse pancreatic islets after transplantation

An adequate revascularization is crucial for islet survival and function after transplantation. Previous studies have suggested that islet revascularization is concluded within 14 days after transplantation. We investigated if the vascular density of transplanted islets and endogenous pancreatic islets differs. Cultured islets were syngeneically transplanted into the kidney, liver, or spleen of C57BL/6 mice. One month later, the graft-bearing organ was removed, and histological specimens were prepared and stained for endothelium with the lectin Bandeiraea simplicifolia. Pancreata from nontransplanted control animals were prepared similarly. Uniform staining of endothelium within the grafts and endogenous islets was obtained. The vascular density was markedly decreased in transplanted islets at all implantation sites, but preferentially in islets implanted into the spleen. The vascular density in the connective tissue surrounding the transplanted islets was very high compared with that of graft intra-islet capillaries. A much lower vascular density was detected in connective tissue surrounding implanted microspheres of a size similar to the islets, which suggests that the islets per se induced blood vessel formation in their vicinity. We conclude that the vascular density in revascularized transplanted islets is markedly decreased compared with endogenous islets. This has potential implications for islet graft metabolism and function.     

Intraportal pig islet xenotransplantation into athymic mice as an in vivo model for the study of the instant blood-mediated inflammatory reaction

Abstract:  One of the main obstacles to successful intraportal islet transplantation is the instant blood-mediated inflammatory reaction (IBMIR) elicited by the isolated islets when exposed to fresh human blood. In the present study, we investigated whether intraportal transplantation of pig islets into diabetic athymic mice could be used as a small animal model to study xenogeneic IBMIR in vivo.
Adult porcine islets (APIs) or rat islets were implanted into the portal vein or under the renal subcapsular space of diabetic athymic mice. Graft survival and morphology were evaluated by measuring blood glucose levels and by performing immunohistochemical staining, respectively. Transplantation of rat islets, irrespective of implantation site, cured all diabetic athymic mice. APIs transplanted subcapsularly also cured all diabetic athymic mice, while none of the animals transplanted with an equivalent amount of APIs via the portal vein remained normoglycemic for more than 10 days after transplantation. Immunohistochemical staining on day 7 showed that most of intraportally transplanted APIs were entrapped in clots and infiltrated with CD11b+ leukocytes. Intraportal transplantation of APIs into athymic mice induced IBMIR, thus providing a small animal model for studying xenogeneic IBMIR.     

Subcutaneous transplantation of macroencapsulated porcine pancreatic endocrine cells normalizes hyperglycemia in diabetic mice

BACKGROUND: The ultimate goal of islet transplantation is the unlimited availability of insulin-secreting cells to be transplanted in a simple procedure that requires no use of immunosuppressive drugs. Immunoisolation of xenogeneic pig islets for transplantation has great potential therapeutic benefits for treatment of diabetes. METHODS: Approximately 4 x 10(6) porcine pancreatic endocrine cells (PEC) isolated from 6-month-old pigs were macroencapsulated in agarose-poly(styrene sulfonic acid) mixed gel and implanted into a prevascularized subcutaneous site in streptozotocin-induced C57BL/6 diabetic mice. Animals receiving an equal number of free porcine PEC were used as controls. After transplantation, nonfasting blood glucose, body weight, intraperitoneal glucose tolerance test, and immunohistologic evaluations were processed. RESULTS: All 10 animals receiving the subcutaneous xenografts of the macroencapsulated porcine PEC normalized hyperglycemia within 5 days after transplantation, maintained the duration of normoglycemia for 24 to 76 days, and gradually gained weight. The subcutaneous xenografts of free porcine PEC could not reverse hyperglycemia. The recipient became hyperglycemic again when the implanted graft was retrieved at day 45 after transplantation. The glucose clearances were significantly ameliorated at day 21 and day 45 after transplantation when compared with those in diabetic mice. The immunohistochemical results revealed an inherent intact structure of the macroencapsulated porcine PEC and positive double-immunofluorescence staining for insulin and glucagon. CONCLUSIONS: Subcutaneous transplantation of macroencapsulated porcine PEC normalized hyperglycemia in diabetic mice. Our results identified a potential for a favorable development of subcutaneous transplantation of porcine PEC as a cure for diabetes.     

骨髓间充质干细胞移植途径对胰岛移植物免疫排斥反应的影响

目的:探讨骨髓间充质干细胞(MSC)与胰岛共移植对诱导胰岛移植物免疫耐受的作用,并比较MSC不同途径移植的效果。方法:SD大鼠和Lewis大鼠分别作为供、受体。取SD大鼠股骨,贴壁培养法分离和扩增MSC,胶原酶V分离胰岛。应用链脲佐菌素制备Lewis大鼠糖尿病模型后,将其随机均分为A组(将BrdU标记的MSC与胰岛经门静脉混合输入),B组(将胰岛经门静脉输入,BrdU标记的MSC经尾静脉输入),C组(胰岛经门静脉输入,联合应用环孢素A)和D组(单纯胰岛门静脉移植)。观察各组术后血糖变化,比较各组胰岛移植物存活时间。术后第7天切取各组部分存活大鼠肝脏、胸腺、脾脏行免疫组化染色观察MSC归巢位置。结果:A,B两组大鼠术后正常血糖维持时间最长,C组次之,D组最短;各组胰岛存活时间A组为(12.1±2.3)d,B组为(8.6±1.4)d,C组为(13.2±1.9)d,D组为(2.2±0.6)d;MSC归巢部位观察显示,A组BrdU阳性的MSC主要分布于肝脏,并在植入胰岛周围形成"类微囊化效应",B组BrdU阳性的MSC主要分布于胸腺、脾脏。结论:MSC与胰岛共移植能诱导胰岛移植物免疫耐受,且MSC和胰岛混合经门静脉移植效果优于胰岛门静脉移植联合MSC外周静脉移植。