微囊化兔甲状旁腺组织异种移植治疗甲状旁腺功能低下症的实验研究

目的探讨不同部位微囊化兔甲状旁腺组织异种移植治疗大鼠甲状旁腺功能低下症的效果。方法应用微囊技术制备微囊化（海藻酸钠-钡生物微胶囊）兔甲状旁腺组织。16只去甲状旁腺的Wistar大鼠按完全随机法分为肾脂肪囊微囊组及腹腔微囊组，每组8只。分别于移植微囊化兔甲状旁腺组织后5、15、25、35、45、55及65d检测血清钙含量，并于移植后第65d取移植物行透射电镜检查。结果移植后，肾脂肪囊微囊组大鼠血清钙水平恢复到正常范围直至观察结束时，透射电镜检查显示移植物存活良好；腹腔微囊组大鼠血清钙水平恢复到正常范围，但第65d时血清钙水平下降至〈1．6mmol／L，透射电镜检查显示移植物中心坏死，仅边缘有少数存活细胞。结论微囊化兔甲状旁腺组织异种移植在不用免疫抑制剂情况下，可以在大鼠体内存活，且有功能。不同移植部位移植后随着时间的延长存在差异，肾脂肪囊在微囊化异种组织移植中是首选的移植部位。     

微囊化新生猪甲状旁腺细胞异种移植的实验研究

目的 探讨微囊化新生猪甲状旁腺细胞异种移植治疗大鼠甲状旁腺功能低下症的效果。方法 应用微囊化技术，制备微囊化（海藻酸钠－聚赖氨酸－海藻酸钠生物微胶囊）新生猪甲状旁腺细胞，32只去甲状旁腺的Wistar大鼠随机分成微囊组、非微囊组、空囊组和对照组，分别移植微囊化新生猪甲状旁腺细胞、甲状旁腺细胞、空微囊及生理盐水。移植后监测血钙及甲状旁腺素水平40周，40周后回收移植物，透射电镜检查。结果 移植后，微囊组大鼠血钙及甲状旁腺素水平恢复到正常范围内，直至观察结束时（40周），透射电镜检查显示移植物存活良好；非微囊组、空囊组和对照组大鼠的血钙及甲状旁腺素水平无改善。结论 微囊化新生猪甲状旁腺细胞异种移植在不用免疫抑制剂情况下，可以在大鼠体内存活，且有功能；海藻酸钠－聚赖氨酸－海藻酸钠生物微胶囊对免疫活性细胞及抗体具有屏蔽作用。     

肝细胞海藻酸钡微囊生物性能的研究

目的　研究肝细胞海藻酸钡微囊的生物学性能。方法　大鼠肝细胞微囊化后移植于腹腔内 ,1个月后取出行组织学检查。结果　不含肝细胞的空囊移植组微囊大多保持良好的形状 ,囊壁光滑、完整 ,囊外无纤维化反应 ,回收率为 ( 89± 2 3) %。肝细胞微囊大部分呈游离状态 ,部分囊外有一薄层纤维层附着 ,回收率为 ( 78± 2 1) % ;囊内细胞存活率由移植前的 ( 91± 16 ) %降至 ( 79±13) %。结论　肝细胞海藻酸钡微囊的生物相容性及机械稳定性较好 ,但免疫源性有待进一步提高。     

微囊化人嗜铬细胞对大鼠异种移植的免疫隔离作用

目的探讨微囊化人嗜铬细胞(ME-HCC)移植于大鼠眼前房或足胝部的免疫隔离作用。方法雌性SD大鼠48只,3月龄,体重180-250g。随机分为3组,HCC组、空微囊组、ME-HCC组,每组16只。HCC组、空微囊组、ME-HCC组分别将HCC、空微囊、ME-HCC移植于大鼠的眼前房(n=8)或足胝部(n=8)。移植术后7d大鼠断尾取血,测定白细胞介素-2(IL-2)、IgG和IgM浓度。移植术后28d 处死大鼠,光镜下观察右侧眼球或左侧足组织形态学变化。结果与HCC组比较,空微囊组和ME- HCC组大鼠血清IL-2、IgG、IgM浓度均降低(P<0.01);ME-HCC、空微囊组血清IL-2、IgG、IgM浓度比较差异无统计学意义(P>0.05)。HCC组大鼠眼前房和足胝部可见大量淋巴细胞和中性粒细胞浸润。空微囊组、ME-HCC组大鼠眼前房和足胝部仅见少量淋巴细胞和中性粒细胞。结论微囊化人HCC 对大鼠异种移植的免疫排斥具有隔离作用。     

海藻酸-壳聚糖-聚乙烯乙二醇微囊生物相容性的研究

目的比较海藻酸-壳聚糖-聚乙烯乙二醇微囊(ACP微囊)和海藻酸-聚赖氨酸-海藻酸微囊(APA微囊)的生物相容性。方法(1)两种微囊(50、100和200个)与健康人血清共浴,检测微囊对补体的激活程度。(2)1000个APA和ACP微囊分别植入Wistar大鼠的腹腔,4d和3周时统计取出的微囊数和微囊的纤维化率。(3)Wistar大鼠胰岛用ACP微囊和APA微囊包裹,分别贯续置于含3.3mmol/L和16.7mmol/L葡萄糖的Hank's溶液中培养,测定培养液中胰岛素的浓度。结果(1)ACP微囊组残余补体活性高于APA微囊组。(2)4d时,ACP和APA微囊的取出数分别是845.0±40.4和807.6±45.7(P>0.05),囊周纤维化率分别是16.40%和65.68%(P<0.05);3周时两种微囊的取出数分别为715.0±133.0和367.5±105.6(P<0.05),囊周纤维化率为27.8%和83.9%(P<0.05)。(3)在含3.3mmol/L葡萄糖的Hank's液中,未微囊胰岛组、APA和ACP微囊化胰岛组的胰岛素浓度分别是(123.48±4.70)mIU/L、(110.11±12.18)mIU/L和(110.90±11.95)mIU/L,当葡萄糖浓度为16.7mmol/L时,胰岛素浓度分别是(754.75±13.81)mIU/L、(689.30±27.71)mIU/L和(684.28±70.10)mIU/L。结论海藻酸-壳聚糖-聚乙烯乙二醇微囊的生物相容性要优于海藻酸-聚赖氨酸-海藻酸微囊,前者更适合应用于微囊化胰岛移植。     

海藻酸-壳聚糖-聚乙烯乙二醇微囊化异种胰岛移植治疗小鼠糖尿病

目的比较海藻酸-聚赖氨酸-海藻酸微囊化(APA)大鼠胰岛和海藻酸-壳聚糖-聚乙烯乙二醇微囊化(ACP)大鼠胰岛移植对小鼠糖尿病的治疗作用.方法链脲霉素220 mg/kg体重腹腔内注射制作小鼠糖尿病动物模型.成模后分成APA微囊组、ACP微囊组和未微囊化胰岛组,每只小鼠腹腔内分别植入200个相应胰岛,检测监测移植前后小鼠的血糖.结果移植后第1天,3组小鼠血糖均较移植前明显降低.未微囊化胰岛移植组小鼠术后第2天血糖均恢复到术前水平;APA微囊组和ACP微囊组小鼠血糖分别维持正常(57.00±14.61)d和(41.67±16.73)d,此两组间差异无显著性(P＞0.05),但均较未微囊化胰岛移植组明显延长(P＜0.05).结论 ACP微囊与APA微囊一样具有免疫隔离作用;ACP微囊化异种胰岛移植可纠正小鼠糖尿病.     

同种异体甲状旁腺组织移植治疗甲状旁腺功能低下的实验研究

目的 探讨甲状旁腺经不同预处理并移植于腹直肌内后甲状旁腺移植物的功能和生存情况.方法 成年雄性Wistar大鼠70只作为供体,成年雄性SD大鼠35只作为受体,建立去甲状旁腺模型受体后采用随机数字表法随机分为直接移植组、高氧培养移植组、环孢素A组、60Co照射移植组及综合处理组5组,每只受体接受2只供体的4个甲状旁腺组织块,甲状旁腺移植于大鼠的腹直肌内.观察各组大鼠在甲状旁腺移植前后不同时相血清钙和甲状旁腺激素(PTH)的变化.结果 各组在甲状旁腺组织移植后,1周内血清钙和PTH均能达到或接近正常水平,与移植前相比差异均有统计学意义(P＜0.01).各组移植物的存活时间不同,直接移植组的存活时间最短,血清钙和PTH维持正常水平的时间分别为3周和4周.高氧培养移植组、环孢素A组、60Co照射移植组以及综合处理组血清钙及PTH维持在正常或接近正常水平的时间分别为5周和8周、6周和8周、5周和7周以及5周和9周;除高氧培养移植组移植术后9周(血清钙)及60Co照射移植组移植术后8周(PTH)差异无统计学意义外,其余4组的血清钙和PTH水平在移植术后4～9周与直接移植组比较其差异均具有统计学意义(P＜0.05),直接移植组较低;高氧培养移植组、CsA组和60Co照射移植组的血清钙和PTH水平在移植术后7～9周低于综合处理组(P＜0.05),综合处理组的血清钙和PTH的维持时间较长.结论 腹直肌内甲状旁腺移植能维持血钙于正常水平;甲状旁腺移植物或受体经预处理后能延长其存活时间.甲状旁腺组织经培养后再移植是治疗甲状旁腺功能减退症的一条有效途径.     

微囊化人胎胰岛移植治疗小鼠实验性糖尿病的观察

目的 :探讨微包囊技术在解决胰岛移植免疫排斥问题中的作用。方法 :将用链脲霉素 (STZ)制备的合格糖尿病模型鼠 2 1只随机分为 3组 ,每组 7只。空囊组腹腔内植入 5 0 0～ 6 0 0个空囊 ,游离胰岛组植入经胶原酶消化制备的人胎胰岛细胞 10 0 0± 10 0个 ,微囊组植入 10 0 0± 10 0个微囊包裹的胰岛细胞。结果 :游离胰岛组和微囊组小鼠在完全停用胰岛素的情况下 ,术后血糖分别降至 7.94± 2 .36mmol.L-1和 7.0 7± 1.15mmol.L-1,与空囊组比较差异有统计学意义 (t=13.170　P <0 .0 0 1,t=2 4 .999　P <0 .0 0 1) ,分别持续 7.4 3± 3.4 2天和 78.4± 2 1.2 7天 (t =8.6 5P <0 .0 0 1)。结论 :该微囊化人胎胰岛移植具有良好的组织相容性和免疫隔离作用 ,明显延长移植胰岛的存活时间     

微囊化甲状旁腺移植现存问题及进展

永久性甲状旁腺功能低下是甲状腺及甲状旁腺术后的一个严重甚至致命的并发症。由于甲状旁腺素在机体代谢中的复杂作用,因而仅靠补充钙剂和维生素D,并不能获得有效改善。甲状旁腺移植一直被视为治疗甲状旁腺功能低下最为理想的方法之一,而排斥反应是同种及异种移植必然面临的一道障碍,使用免疫抑制剂抑制排斥反应的同时,却带来全身免疫功能被抑制的严重后果。微囊包被技术的出现,为最终解决甲状旁腺移植免疫排斥问题提供了可能。微囊化移植技术的原理,是用具有组织相容性的选择性半透膜包被移植物,保护移植物免受受者的免疫攻击,同时又能为移植物提供必需的氧和营养物质。1979年,Li m等[1]应用海藻酸和聚赖氨酸制成的微囊成功包被(微囊化)哺乳动物的活体细胞和组织,体外实验显示,囊内组织或细胞继续生长繁殖,并保持完整的功能和形态。1980年Li m和Sun报道了微囊化大鼠胰岛移植,接受移植的同基因糖尿病大鼠术后维持正常血糖2~3周。1989年,Sun等将微囊化大鼠甲状旁腺细胞移植给切除了甲状旁腺的同基因大鼠,结果术后受者的血钙和血甲状旁腺激素(PTH)明显升高,接近正常,且持续8周[2]。从此开启了微囊化甲状旁腺移植的研究。1994年,Has...     

BPA微囊与APA微囊机械强度和生物相容性的比较研究

目的 比较海藻酸钡-多聚赖氨酸-海藻酸(BPA)微囊与海藻酸-多聚赖氨酸-海藻酸(APA)微囊的生物相容性和机械强度的生物物理特性.方法 用静电微囊发生仪制备BPA和APA微囊,通过机械振荡法和肌肉下移植来检测微囊的机械强度.通过微囊大鼠腹腔移植来观察BPA和APA微囊的生物相容性.结果 机械振荡48h后APA微囊的破损率为4.3%,BPA微囊仅为1.5%;肌肉下移植1个月后,组织切片H&E染色显示,APA和BPA微囊均保持完整,仅有轻度纤维化包裹;腹腔移植4、8和10周后,从大鼠腹腔内取出的微囊中95%～98%为结构完整,呈圆形,表面光滑,光镜下无明显的结缔组织包绕.结论 所制备的BPA微囊的生物相容性河机械强度优于APA微囊.     

Microencapsulated parathyroid cells as a bioartificial parathyroid. In vivo studies

Parathyroid cells were isolated from healthy rats, encapsulated in alginate-polylysine membranes, and injected intraperitoneally into rats on which total parathyroidectomies had been performed. Three days posttransplant, serum calcium and PTH-M concentrations had increased to near-normal levels in the recipient animals. Similar results were observed in a separate group of parathyroidectomized rats 3 days after free parathyroid cells were implanted, but within 4 weeks serum calcium and PTH-M concentrations had decreased almost to pretransplant levels in these rats. In the rats with encapsulated cell transplants, by contrast, serum calcium and PTH-M levels were significantly higher, even after 8 weeks. No therapeutic effects were observed in rats injected with empty capsules or in the control group, which received no capsules or cells. These results indicate that transplants of microencapsulated parathyroid cells can temporarily reverse aparathyroidism in rats without the use of immunosuppressive drugs, and that further studies are warranted to investigate possible future clinical applications of this treatment.     

Microencapsulation of parathyroid tissue with photosensitive poly(L-lysine) and short chain alginate-co-MPEG

Human parathyroid glands were encapsulated using the alginate-PLL system in this study. In order to improve the mechanical strength and the biocompatibility, the microcapsules were fabricated with a three-layer structure that consisted of alginate/photosensitive poly(L-lysine)/short chain alginate-co-MPEG. These modified microcapsules were used for encapsulating human parathyroid tissue. In vitro experiments revealed that microencapsulated parathyroid glands maintained differentiative properties in culture, and the capsular membrane was freely permeable to the human parathyroid hormone. For in vivo experiments, these capsules were transplanted into parathyroidectomized SD-rats. After parathyroidectomy, serum calcium decreased from 2.25 to 1.68 mmol/L and remained in a constantly low concentration until transplantation. Parathyroidectomized SD-rats were normocalcemic after transplant of encapsulated parathyroid tissue. The microcapsules were then explanted at 12 weeks for examination. Histological evaluations of excised transplants revealed that the microcapsules remained intact structurally and were free of cell adhesions. The results demonstrated that human parathyroid tissue microencapsulated by this system retains stability and is functional both in vitro and in vivo. This encapsulating system will have valuable application for endocrine surgery in the future.     

高血磷对慢性肾衰竭大鼠血管钙化的影响

目的 研究高血磷对慢性肾衰竭大鼠血管钙化的影响。 方法 44只Wistar雄性大鼠分别行5/6肾切除（n=24，模型组）或假手术（n=20，对照组），39只大鼠术后4周开始给予高磷或低磷饮食10周。动物分4组：模型组+高磷饮食(CHP)，模型组+低磷饮食(CLP)，对照组+高磷饮食(NHP)，对照组+低磷饮食(NLP)。高磷饮食配方：磷（P）1.2%, 钙（Ca）1.6%，维生素D 1 IU/kg；低磷饮食配方：P 0.2%, Ca 0.5%，维生素D 1 IU/kg。特定饮食开始（基线）和结束时称体质量；检测Scr、血P、血Ca、1,25(OH)2D3、全段甲状旁腺激素（iPTH）。特定饮食结束时处死大鼠，取胸主动脉组织，采用Von Kossa染色和钙含量测定判断血管钙化程度，同时检测核心结合因子α1（Cbfα-1）mRNA的表达。 结果 术后第4周特定饮食开始时，模型组大鼠Scr水平显著高于对照组大鼠 [（94.4±17.6）比（36.4±0.6）μmol/L，P < 0.05]，余各项指标组间差异无统计学意义。特定饮食10周时，4组间体质量差异无统计学意义；各组各时间点血Ca水平差异均无统计学意义；血1,25(OH)2D3水平除了在NLP组显著增高外，余3组间差异均无统计学意义；CHP组血P和iPTH水平显著增高，出现严重血管钙化、程度3～4级；胸主动脉钙含量明显增高，同时Cbfa-1 mRNA表达显著上调。血P水平对胸主动脉钙含量的影响比iPTH水平更强（β ＝ 0.832>0.267）。血P水平与胸主动脉钙含量、Cbfα-1 mRNA表达量呈直线正相关（r = 0.672～0.73，P < 0.05）。 结论 高血磷是导致慢性肾衰竭大鼠血管钙化的重要因素。 Cbfα-1的表达上调可能是其导致血管钙化的机制之一。     

Long-term normoglycemia in rats receiving transplants with encapsulated islets

BACKGROUND: To follow up on previously successful transplantation of encapsulated islets in mice, the present study was performed in rats to determine the effects of several factors, including alginate composition and concentration of cross-linking agent and capsule size on the effectiveness of encapsulated islets. METHODS: Highly purified alginate of either high guluronic acid or high mannuronic acid (M) with low endotoxin content was used. Regular-size (0.8-1.1 mm) or small microcapsules (0.5-0.7 mm) were produced by cross-linking with BaCl2 without additional poly-L-lysine coating and were transplanted into abdominal cavity of normoglycemic (empty capsules) or streptozotocin induced diabetic Lewis rats (islet containing capsules). RESULTS: Empty regular-size capsules made of different alginate compositions had similar biocompatibility and stability results. Compared with empty capsules, regular-size capsules made of high-M alginate containing syngeneic islets had inferior stability indicated with lower fractional volume retrieved. Islet-containing smaller-size microcapsules made of high-M alginate were more stable and had less cellular attachment compared with the regular-size capsules, although the normoglycemic period was comparable between two groups of rats receiving transplants with smaller-size microcapsules (48+/-8 days, n=8) or regular-size capsules (59+/-11 days, n=4) in allogeneic experiments. In syngeneic experiments, all of the rats (n=4) maintained normoglycemia up to 210 days after transplantation. CONCLUSION: These results indicate that regular-size alginate capsules do less well in rats than in our previous experiments with mice. Smaller capsules made of alginate cross-linked with barium appear to provide better stability and may be a useful strategy for use in larger recipients.     

Assessment of parathyroid autotransplantation for preservation of parathyroid function after total thyroidectomy

BACKGROUND: Hypoparathyroidism with permanent hypocalcemia is a well-recognized complication after thyroid surgery. AIM: This study was conducted to assess the role of immediate parathyroid autotransplantation in the preservation of parathyroid function after total thyroidectomy. PATIENTS AND METHODS: Twenty-eight patients had autotransplantation of parathyroid glands resected or devascularized during total thyroidectomy. Data were collected prospectively regarding demographics, indication for surgery, operative procedure, pathologic diagnosis, number of glands transplanted, and subsequent course. Thyroid nodules were evaluated by ultrasonography, radionuclide scanning, and/or fine-needle aspiration cytology. All patients had serum ionized calcium, phosphorus, and intact parathyroid hormone (PTH) levels measured preoperatively and monitored regularly postoperatively for a period of 14 weeks and again at 6 months after operation. Patients were categorized into three groups according to the number of glands transplanted: one (group 1, n = 6), two (group 2, n = 14), or three glands (group 3, n = 8). In three other volunteers, one parathyroid gland was transplanted in the brachioradialis and subjected to electron microscopy 1, 2, and 4 weeks after transplantation. RESULTS: Total thyroidectomy was performed for malignant disease in 16 patients (57.1%) and for benign disease in 12 (42.9%) patients. All patients reverted to asymptomatic normocalcemia without the need for any medications within 4 to 14 weeks. Normal levels of serum markers were regained slower when one gland was transplanted compared with two or three glands (P <.01). Electron microscopic examination showed evidence of ischemic degeneration in the transplanted tissues 1 week postoperatively. Regeneration started by the second week and coincided with normalization of PTH levels. Optimum resting and nearly normal status of parathyroid tissue was achieved by the fourth week. CONCLUSIONS: This study showed that active PTH production coincides with regeneration of parathyroid cells and that autotransplantation of at least two resected or devascularized glands during total thyroidectomy nearly eliminates permanent postoperative hypoparathyroidism, thus improving the safety of total thyroidectomy performed for malignant or benign disease.     

Severe hyperparathyroidism with bone abnormalities and metastatic calcification in rats with adenine-induced uraemia.

BACKGROUND: Marked parathyroid hyperplasia with bone diseases and vascular calcification are unsolved issues in dialysis patients. In this study, we made azotemic model rats by adenine feeding and analyzed the development and progression of the abnormalities. METHODS: Renal failure was induced in 8-week-old male Wistar rats by feeding 0.75% adenine-containing diet for 6 weeks. Serum parameters, parathyroid hyperplasia, bone changes and metastatic calcification were examined at 2, 4 and 6 weeks. RESULTS: Progressive increase of serum creatinine and inorganic phosphate, and decreased levels of serum calcium and 1,25(OH)2D3 were confirmed. Markedly enlarged parathyroid glands and extremely high PTH levels were observed in all adenine-fed rats compared with the control (PTH: 199.3+/-58.0 vs 10.5+/-3.0 pmol/l, P<0.01, respectively, at 6 weeks). In cortical bone of the femur, the morphometric parameters showed increased bone resorption with increased fibrosis, whereas in the trabecular bone, bone resorption decreased and bone volume increased with a larger amount of osteoid compared with the control. Metastatic calcification in aorta, coronary artery and other soft tissues were also found in adenine-fed rats. CONCLUSIONS: Uraemic rats made by adenine diet developed severe abnormalities of calcium metabolism in a relatively short period and therefore they may serve as a useful model for the analysis of parathyroid hyperplasia and vascular calcification in chronic renal failure.