Warfarin or Low-Molecular-Weight Heparin Therapy does not Prolong Pig-To-Primate Cardiac Xenograft Function

Microvascular thrombosis is a prominent feature in cardiac delayed xenograft rejection (DXR). We investigated the impact of warfarin or low-molecular-weight heparin (LMWH) anti-coagulation on xenograft function using a heterotopic pig-to-primate model. Donor hearts were from CD46 transgenic pigs and baboon immunosuppression included tacrolimus, sirolimus, anti-CD20 and TPC, an alpha-galactosyl-polyethylene glycol conjugate. Three groups of animals were studied. Group 1 (n = 9) was treated with warfarin, Group 2 (n = 13) with LMWH and Group 3, received no anti-coagulant drugs. The median duration of xenograft function was 20 days (range 3-62 days), 18 days (range 5-109 days) and 15 days (range 4-53 days) in Groups 1 to 3 respectively. Anti-coagulation achieved the targeted international normalized prothrombin ratio (INR) and anti-factor Xa levels consistent with effective in vivo therapy yet, no significant impact on median xenograft function was observed. At rejection, a similar histology of thrombosis and ischemia was apparent in each group and the levels of fibrin deposition and platelet thrombi in rejected tissue was the same. Anti-coagulation with warfarin or LMWH did not have a significant impact on the onset of DXR and microvascular thrombosis. However, a role for specific anti-coagulant strategies to achieve long-term xenograft function cannot be excluded.     

Human CD4+CD25+ Regulatory T Cells Suppress Anti-Porcine Xenogeneic Responses

Due to the shortage of human organs, xenotransplantation is being explored as an alternative to allotransplantation, but immune rejection remains a major hurdle to its implementation. We tested the ability of human CD4+CD25+ T cells (Treg cells) to suppress CD4+ T cell-mediated anti-porcine xenoresponses usingin vitroassays. Human Treg cells were hyporesponsive to porcine cell stimulation and suppressed the proliferative response of CD4+CD25- T cells in a dose-dependent manner, and comparison of the allo- and xenoresponses indicated that more Treg cells might be required to suppress the xenogeneic response than the allogeneic response. Stimulation of CD4+CD25- T cells with porcine cells resulted in secretion of IFN-gamma, TNF-alpha, IL-10, IL-6 and IL-2, and Treg cells suppressed the secretion of these cytokines, as well as the CD4+CD25- T-cell cytolytic response against porcine cells. These results suggest a potential role for Treg cells in promoting xenograft survival.     

大鼠胰岛与生长因子共微囊提高囊内胰岛存活率

目的 探讨微胶囊胰岛皮下移植治疗化学性糖尿病小鼠和生长因子(growth factor,GF)与大鼠胰岛共微囊对提高囊内胰岛存活率的作用.方法 选取C57BL/6雄性小鼠皮下预血管化糖尿病模型25只,行微胶囊大鼠胰岛皮下移植.随机分为5组,每组5只.①A组:GF与大鼠胰岛共微囊移植组;②B组:微胶囊大鼠胰岛移植组;③C组:GF微囊移植组;④D组:大鼠胰岛移植组;⑤E组:空囊移植组.观察受体小鼠的血糖和体重变化,移植后8周比较微胶囊内胰岛存活数.结果 移植后1周至移植后3周A组与B组间血糖均有非常显著差异(P＜0.01),移植后4周至移植后8周A组与B组间血糖无显著差异(P＞0.05),移植后1周至移植后4周B组与C组间血糖均有非常显著差异(P＜0.01).C组血糖异常升高,移植4周后小鼠陆续死亡.D组和E组移植无效.A组和B组间各实验点小鼠体重均无显著差异(P＞0.05),A组小鼠体重成模时下降,移植2周后开始上升.A组和B组胰岛存活数有非常显著差异(F=36.84,P＜0.01).结论 GF与大鼠胰岛共微胶囊移植,GF可促进胰岛的细胞增殖和再生,显著提高囊内胰岛的存活率.     

胎儿卵巢组织玻璃化冻存效果的研究

目的探讨玻璃化冻存法对胎儿卵巢组织形态和功能的保存效果。方法采用改良EG5.5/30玻璃化液冻存胎儿卵巢皮质片,解冻后观察卵巢组织学变化,卵巢皮质片异种异位移植后,观察受体鼠动情周期恢复率、恢复时间、卵泡发育状况。结果实验组与新鲜培养后移植组、添加抗氧化剂培养后移植组相比动情周期恢复率差异无统计学意义(P>0.05),但高于新鲜移植组(P<0.005);动情周期恢复需要的天数接近于新鲜移植组,明显短于两种培养组(P<0.05);在卵泡计数上,实验组每高倍视野的卵泡计数明显高于新鲜移植组(P<0.005),与培养后移植组间的差异无统计学意义(P>0.05)。移植后18周,组织学观察见大量窦卵泡,而培养组仅偶见窦卵泡。结论玻璃化冻存法可有效冻存胎儿卵巢组织,且不影响卵泡继续发育的潜能。     

胎猪皮肤前体组织异种移植模型的研究

目的探讨胎猪皮肤前体组织异种移植模型及移植后发育过程。方法取精确胎龄为56d的胎猪皮肤前体组织,分组进行移植,①背部创面模型组：制备成微粒皮后移植到BALB／c裸鼠背部创面,以人尸体皮覆盖;背部皮下模型组：制备成小张邮票皮,植入裸鼠背部皮下;耳廓皮下模型组：制备成微粒皮植入裸鼠耳廓皮下。各组于移植后观察其生长发育特性,并于移植后6周和12周取材行HE染色观察其组织结构形态。新生组织块大小采用双样本t检验。结果各模型的胎猪皮肤前体组织移植后均能存活并继续生长,背部创面模型组生长能力显著大于耳廓皮下模型组,新生皮肤组织均具有真皮和表皮,耳廓皮下模型的真皮附属器仅见毛囊（毛发）．偶见皮脂腺,未见汗腺,但是背部创面模型组及背部皮下模型组不仅能发育成毛囊（毛发）、还见大量皮脂腺和汗腺。结论背部创面移植模型最适合于胎猪皮肤前体组织异种移植及移植后发育的研究。