海藻酸钠—多聚赖氨酸—海藻酸钠微囊化胰岛细胞移植治疗糖尿 …

采用Ｓｕｎ海藻酸钠－多聚赖氨酸－海灌酸钠（ＡＰＡ）微囊制作技术，分别包裹大鼠胰岛素分泌细胞系，移植于糖尿病小鼠腹腔。结果表明ＡＰＡ微囊化大鼠胰岛或胰岛素分泌细胞，均可使糖尿病小鼠血糖降低至拉近正常水平达３周至１１０天，移植微囊无明显的组织学反应。证明该ＡＰＡ微囊化胰岛细胞移植具有较好的治疗效果，微囊具有较好的生物相容性和免疫隔离作用。进一步发展生物型人工胰尊定了基础。     

微囊化大鼠胰岛移植物的制备与异种移植

为降低胰岛移植中排斥反应，用海藻酸钠－聚赖氨酸生物膜制备微囊化大鼠胰岛，体外培养，胰岛素释放试验功能良好，胰岛素释放量与单纯胰岛差异无显著意义；异种移植可成功地纠正糖尿病小鼠的高血糖状态平均达４个月之久。表明：大鼠，胰岛微囊化可在不便用免疫抑制剂的情况下，有效地延长胰岛在糖尿病小鼠体内的生存期。     

糖尿病犬经肝动脉肝内移植微囊化猪胰岛细胞的安全性和有效性

目的评估移植于I型糖尿病犬肝脏中的微囊化新生猪胰岛细胞(NPI)的生物相容性、免疫学特性及生理学特性。方法I型糖尿病犬分为A、B两组,每组15只,A组每只犬分别经肝动脉灌注微囊化新生猪胰岛细胞40～60万个,B组每只犬分别经肝动脉灌注未微囊化新生猪胰岛细胞40～60万个,两组动物移植后均不使用免疫抑制治疗。移植前后分别测量移植受体的肝脏功能及淋巴细胞CD4 /CD8 比值。移植6个月后所有移植受体的肝脏均进行病理学检查。结果移植后A组外源性胰岛素用量从移植前的22 u逐渐降至5 u,B组所需外源性胰岛素从移植前的24 u下降至10 u。移植后2～3周B组胰岛素用量恢复到移植前的水平,而A组的部分动物的胰岛素剂量继续减至8 u。B组受体移植后血的CD4 较移植前升高,而A组的CD4 和CD8 细胞移植后无明显变化。移植后所有受体的肝功能及组织结构未见异常。结论微囊化的新生猪胰岛细胞在受体犬的肝脏中有很好的生物相容性。微囊可以延长移植物的存活,且异种移植微囊化的新生猪胰岛细胞能够纠正糖尿病犬的高血糖状态。     

微囊化牛嗜铬细胞移植于脊髓蛛网膜下镇痛作用的研究

采用微囊化牛嗜铬细胞（ＢＣＣ）异种移植于大鼠和癌痛病人疹髓蛛网膜下方法,观察ＢＣＣ镇痛作用和海藻酸钠－聚赖氨酸－海藻酸钠（ＡＰＡ）微衰对异种移植物的免疫保护作用。结果显示,移植后微囊组和非微囊组织大鼠基础热痛阈和尼古丁激发热痛阈明显升高,微囊组８０％受试鼠的镇痛特续时间超过２７０天,将微囊化ＢＣＣ樾入８例癌痛疾人朱网膜下,除１例痛效果不明显外７例缓解,减少或停止使用止痛药,镇痛作用持续时间〉６０天     

APA微囊化胰岛研究进展

微囊化胰岛是从20世纪80年代发展起来的细胞移植治疗糖尿病的重要方法。海藻酸-聚赖氨酸-海藻酸微囊(APA)具有广阔的应用前景。本文综述了近年来微囊化胰岛的研究进展，重点分析了微囊材料的生物相容性，微囊的完整性，微囊的移植部位等影响APA微囊治疗效果的因素，以期为完善微囊化胰岛的治疗效果提供线索。     

重视微囊化人工细胞在医学中应用的研究

组织细胞移植可以治疗多种神经／内分泌及代谢疾病。异种细胞和基因工程细胞可提供来源广泛的具有特定功能的移植物。海藻酸钠－聚赖氨酸－海藻内（ＡＰＡ）微囊包裹移植物可有效的克服免疫排斥,使异种移植物得以在宿主体内长期存活并发挥效应。ＡＰＡ微化工细胞已在治疗帕金森病、疼痛、糖尿病等疾病的研究中取得了很大的进展。我国在领域的研究水平已处于国际先进行列。严格控制所用目的细胞和微囊的质量,是保证研究健康发展的必     

微囊化猪甲状腺组织移植治疗甲状腺功能减退大鼠的实验研究

海藻酸钠－多聚赖氨酸－海藻酸钠（ＡＰＡ）微囊化猪甲状腺组织移植治疗２８只实验性甲状腺功能减退大鼠，对照组１７只移植非微囊化猪甲状腺组织。结果显示，移植后两组受体的Ｔ３、Ｔ４水平升高，其中对照一更为显著，但９周后明显下降，甚至低于移植前水平。而实验组保持持续升高，超过４０周；移植后两组受体的ＴＳＨ水平均明显下降，但以实验组为显著，而且持续降低超过４０周。而对照组维持时间较短，移植９周后开始回升。移植     

微囊化件肾上腺髓质嗜铬细胞脑内移植治疗偏侧帕金森病样大 …

以右侧帕金森病样大鼠和猴为模型,分别将微囊化和非微囊化牛肾上腺嗜铬细胞（ＢＣＣ）及空微囊定向植入右侧脑纹状体内,观察动物行为、脑组织生化和组织变化。结果表明,植入的ＢＣＣ能够在异种脑内存活,分泌多巴胺等单胺类物质并纠正帕金森病样大鼠及猴的异常行为。海藻酸钠－聚赖氨酸－海藻酸钠微囊具有免疫保护作用,可明显地延长ＢＣＣ在异种宿主脑内的顾活时间,作用超过１０个月。微囊化ＢＣＣ脑内移植有望成为治疗帕金森病     

微囊化牛肾上腺髓质嗜铬细胞脑内移植治疗偏侧帕金森病样大鼠及猴的实验研究

以右侧帕金森病样大鼠和猴为模型,分别将微囊化和非微囊化牛肾上腺嗜铬细胞（ＢＣＣ）及空微囊定向植入右侧脑纹状体内,观察动物行为、脑组织生化和组织学变化。结果表明：植入的ＢＣＣ能够在异种脑内存活、分泌多巴胺等单胺类物质并纠正帕金森病样大鼠及猴的异常行为。海藻酸钠－聚赖氨酸－海藻酸钠微囊具有免疫保护作用,可明显地延长ＢＣＣ在异种宿主脑内的存活时间,作用超过１０个月。微囊化ＢＣＣ脑内移植有望成为治疗帕金森病的一种有效方法。     

微囊技术在生物医学中应用的研究进展

微囊技术（encapsulation）是指用半透膜包被生物活性物质以形成微囊的技术，形成的微囊可以阻遏免疫细胞以及大分子抗体通过半透膜，同时允许氧气、营养物质和一些具有生物活性的小分子物质自由出入，因此，微囊技术是目前细胞治疗、组织和器官替代治疗的主要方法之一。微囊技术的应用可以追溯到1933年，Bisceglie运用复合膜包被肿瘤细胞移植到猪的腹腔，结果发现移植的细胞并没有受到免疫系统的破坏。1964年，Chang再次引用微囊技术进行细胞移植，并首次提出“人工细胞”的概念。随后的20年问，人们不断尝试用这种方法包埋胰岛细胞来控制糖尿病小动物模型的高血糖。1980年，Lim等首次成功地用微囊化胰岛细胞移植纠正糖尿病动物高血糖。1986年，0’Shea等在已有基础上对成囊物质进行了革新，制成了海藻酸钠多聚赖氨酸海藻酸钠（APA）微囊。近几年来，许多实验室探索采用其他方法和材料研制新型微囊，试图改善微囊的一些生物学和化学特性，以使其能够在代谢性疾病的治疗、药物缓释控制、体内和体外细胞培养等领域得到广泛应用。本文仅就微囊技术在生物医学领域中的应用进行综述。     

模拟微重力条件下大鼠胰岛培养及体内移植的实验研究

目的研究经模拟微重力条件培养的胰岛是否能够降低胰岛移植过程中引发的免疫排斥反应，进而延长胰岛的体内存活时间。方法分离新鲜胰岛，应用培养皿对胰岛进行静态培养，同时应用旋转式生物反应器对胰岛进行三维立体培养。应用吖啶橙一碘化丙啶（AO-PI）染色和葡萄糖刺激实验对3种条件下培养得到的胰岛进行生物学活性研究。2000当量胰岛在旋转式生物反应器中培养5d后，将其移植入经链脲佐菌素（STZ）处理的糖尿病模型SD大鼠。肾被膜下作为实验组，以新鲜分离的胰岛和静态培养5d的胰岛移植入经STZ处理的糖尿病模型SD大鼠肾被膜下作为对照组。在不同时间点上，检测各组SD大鼠血糖变化情况；对各移植组中大鼠进行糖耐受实验。切除。肾被膜下的移植物组织作为标本，进行苏木精一伊红（HE）染色及胰岛素组织化学染色检测。结果体外检测结果表明，与新鲜分离的胰岛和静态培养的胰岛相比，微重力条件下培养的胰岛仍保持良好的胰岛素合成及分泌功能。体内实验表明，微重力条件下培养的胰岛体内移植组的血糖保持正常的时间明显高于接受静态培养的胰岛和新鲜分离的胰岛移植组。将微重力培养条件下胰岛移植大鼠后，取。肾被膜下移植区组织标本进行HE染色，未见明显淋巴细胞浸润，胰岛素免疫组织化学均可见阳性细胞。而新分离的胰岛以及静态培养的胰岛移植后，大鼠。肾被膜下移植物组织标本可见淋巴细胞浸润，移植物的厚度明显变小。结论胰岛在微重力条件下培养可降低移植引起的免疫排斥反应，进而延长移植物体内存活时间。     

胰岛移植研究的现状及展望

糖尿病是严重危害人类健康的常见病和多发病,胰岛移植因其手术简单、安全、并发症少,可纠正糖代谢紊乱,尤其是可防止、减缓甚至逆转并发症,降低病死率,成为1型糖尿病治疗最安全、有效的方法。自2000年Edmonton方案获得成功以来,胰岛移植的临床疗效越来越受到人们关注。目前,胰岛移植研究的主要策略是从提高正常活性胰岛获得率,选择最优移植途径,改良抗排异方法等各相关环节入手,提高移植成功率。人胰岛供体缺乏是制约其临床应用无法解决的问题。解决供体短缺的可能方法有:1.异种胰岛;2.干细胞源胰岛;3.来自活体人胰腺供体的胰岛。胰岛移植将为介入放射学开辟一个全新的应用领域。     

大鼠胰岛细胞原代培养方法比较研究

目的：比较减碎消化法和原位灌注消化法在大鼠胰岛细胞原代培养中的优缺点,探讨一种简单易行的大鼠胰岛细胞培养方法。方法：雄性SD大鼠30只随机分成减碎组（CC组,n=15）,胰腺剪为小组织块后,Ⅴ型胶原酶逐级消化分离;原位灌注组（YY组,n=15）,采用胆总管逆行灌注Ⅴ型胶原酶分离胰岛。双硫腙（DTZ）染色检测胰岛纯度,葡萄糖刺激胰岛素释放试验检测胰岛功能。结果：2组获得的胰岛对于葡萄糖刺激均具有良好的分泌活性（P〈0.01）;YY组比CC组获得的胰岛数量多（P〈0.01）,形态较好,等量胰岛的胰岛素释放量亦多（P〈0.05）。结论：胆总管原位灌注Ⅴ型胶原酶消化可以获取数量多,活性和纯度较好的胰岛。     

Imaging pancreatic islet cells by positron emission tomography

It was estimated that every year more than 30000 persons in the United States - approximately 80 people per day - are diagnosed with type 1 diabetes (T1D). T1D is caused by autoimmune destruction of the pancreatic islet (β cells) cells. Islet transplantation has become a promising therapy option for T1D patients, while the lack of suitable tools is difficult to directly evaluate of the viability of the grafted islet over time. Positron emission tomography (PET) as an important non-invasive methodology providing high sensitivity and good resolution, is able to accurate detection of the disturbed biochemical processes and physiological abnormality in living organism. The successful PET imaging of islets would be able to localize the specific site where transplanted islets engraft in the liver, and to quantify the level of islets remain alive and functional over time. This information would be vital to establishing and evaluating the efficiency of pancreatic islet transplantation. Many novel imaging agents have been developed to improve the sensitivity and specificity of PET islet imaging. In this article, we summarize the latest developments in carbon-11, fluorine-18, copper-64, and gallium-68 labeled radioligands for the PET imaging of pancreatic islet cells.     

Evaluation of Porcine Pancreatic Islets Transplanted in the Kidney Capsules of Diabetic Mice Using a Clinically Approved Superparamagnetic Iron Oxide (SPIO) and a 1.5T MR Scanner

Objective

To evaluate transplanted porcine pancreatic islets in the kidney capsules of diabetic mice using a clinically approved superparamagnetic iron oxide (SPIO) and a 1.5T MR scanner.

Materials and Methods

Various numbers of porcine pancreatic islets labeled with Resovist, a carboxydextran-coated SPIO, were transplanted into the kidney capsules of normal mice and imaged with a 3D FIESTA sequence using a 1.5T clinical MR scanner. Labeled (n = 3) and unlabeled (n = 2) islets were transplanted into the kidney capsules of streptozotocin-induced diabetic mice. Blood glucose levels and MR signal intensities were monitored for 30 days post-transplantation.

Results

There were no significant differences in viability or insulin secretion between labeled and unlabeled islets. A strong correlation (r² > 0.94) was evident between the number of transplanted islets and T₂ relaxation times quantified by MRI. Transplantation with labeled or unlabeled islets helped restore normal sustained glucose levels in diabetic mice, and nephrectomies induced the recurrence of diabetes. The MR signal intensity of labeled pancreatic islets decreased by 80% over 30 days.

Conclusion

The transplantation of SPIO-labeled porcine islets into the kidney capsule of diabetic mice allows to restore normal glucose levels, and these islets can be visualized and quantified using a 1.5T clinical MR scanner.     

Feasibility of baculovirus-mediated reporter gene delivery for efficient monitoring of islet transplantation in vivo

ObjectiveThe objective of this study was to explore the feasibility of baculovirus vector-mediated sodium iodide symporter (NIS) gene delivery to monitor islet transplantation.MethodsBaculovirus vectors expressing green fluorescent protein (GFP) or NIS (Bac-GFP and Bac-NIS) were established using the Bac-to-Bac baculovirus expression system. The GFP expression of Bac-GFP-infected rat islets was observed in vitro by fluorescence microscopy. Iodine uptake and inhibition of iodine uptake by NaClO₄ in Bac-NIS-infected islets were dynamically monitored in vitro. Bac-GFP- or Bac-NIS-infected islets were implanted into the left axillary cavity of NOD-SCID mice, and fluorescence imaging and ¹²⁵I NanoSPECT/CT imaging were subsequently performed in vivo.ResultsBac-GFP efficiently infected rat islets (over 95% infected at MOI = 40), and the expression of GFP lasted approximately two weeks. NaClO₄ could inhibit iodine uptake by Bac-NIS-infected islets. In vivo imaging revealed that the fluorescence intensity of the transplant sites in Bac-GFP-infected groups was significantly higher than in the non-infected group. Grafts could be clearly observed by ¹²⁵I NanoSPECT/CT imaging for up to 8 h.ConclusionBaculovirus vectors are powerful vehicles for studying rat islets in gene delivery. It is feasible to use a baculovirus vector to delivery an NIS gene for non-invasive monitoring transplanted islets in vivo by the expression of the target gene.     

bcl-2基因转染对大鼠胰岛细胞培养的影响

目的探讨bcl-2基因转染对培养的胰岛细胞凋亡和生物活性的影响。方法用腺病毒介导的基因转染方法把bcl-2转染人胰岛细胞，用RT—PCR和免疫细胞化学方法检测转染细胞中bcl-2的表达，原位末端标记（TUNEL）检测细胞凋亡，台盼蓝测定细胞活度，放免法测定培养液巾胰岛素水平了解胰岛功能。结果转染的胰岛细胞中70％的细胞有bcl-2蛋白的表达，转染细胞的凋亡率为6％，对照组为22死，转染胰岛细胞的活度为91％，对照组为68％，转染胰岛细胞在高糖培养基中胰岛素水平高于对照组。结论腺病毒介导的基冈转染方法能成功转染胰岛细胞，bcl-2基因转染能降低细胞凋亡率，改善胰岛细胞功能。     

Technique, complications, and therapeutic efficacy of percutaneous transplantation of human pancreatic islet cells in type 1 diabetes: the role of US

PURPOSE: To retrospectively evaluate the role of ultrasonography (US) with regard to the technique, complications, and therapeutic efficacy of percutaneous intrahepatic transplantation of human pancreatic islet cells with combined US and fluoroscopic guidance. MATERIALS AND METHODS: The institutional review board approved the study, and informed consent was obtained from all patients. After kidney transplantation, 34 uremic diabetic patients (20 men, 14 women; mean age, 40.9 years; age range, 29-61 years) underwent percutaneous intrahepatic transplantation of islet cells. Portal vein patency and liver echotexture were preliminarily assessed with color Doppler US. US also was used to identify early complications and presence (group A patients) or absence (group B patients) of hepatic parenchymal changes. Differences between the two groups in C peptide serum level and range were analyzed (Mann-Whitney test). Therapeutic efficacy of transplantation was assessed with regard to insulin independence period (rate and duration), exogenous insulin requirement, glycated hemoglobin, and C peptide level. A C peptide level of more than 0.5 ng/mL was considered to indicate well-functioning islet cells. RESULTS: Fifty-eight procedures were technically successful, with a single puncture used in 51 of 58 patients. Complications occurred in three of 58 patients (hemoperitoneum, hemothorax, and thrombosis in one patient each) and were conservatively treated and resolved. Duration of insulin independence in 12 patients was more than 3 months (mean, 21 months). Well-functioning islet cells at 6 years were found in 19 of 34 patients. Hyperechoic parenchymal changes were evident at US in 12 of 34. No statistically significant difference in C peptide level was found between groups (P > .05), but a wider range of values was recorded in group B. CONCLUSION: Complication rate of transplantation with US and fluoroscopic guidance was low. Well-functioning islet cells were found in about 50% of patients at 6 years of follow-up. Hepatic implantation of islet cells was evident on US images in more than one-third of patients.