Programa de Anatomía y Biología del Desarrollo, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago.
Placenta. 2011 May;32(5):356-61. doi: 10.1016/j.placenta.2011.02.005. Epub 2011 Mar 21.
Chagas' disease, produced by the haemoflagellated protozoan Trypanosoma cruzi (T. cruzi), is one of the most frequent endemic diseases in Latin America. In spite that in the past few years T. cruzi congenital transmission has become of epidemiological importance, studies about this mechanism of infection are scarce. The placental tissue undergoes apoptosis throughout gestation, as part of its normal turnover. On the other hand, it is known that T. cruzi induces, delays or inhibits apoptosis in other mammalian tissues. In order to determine the effect of parasite invasion on normal apoptosis in the placenta, explants of human chorionic villi were incubated with 105 trypomastigotes for 24 h. Effective infection was tested by visualizing T. cruzi antigens in histological preparations and by PCR. Upon infection, apoptotic cell death was determined by light and transmission electron microscopy, TUNEL analysis, measurement of caspase-3 like activity and immunohistochemical detection of caspase 3 cleaved cytokeratin 18. Our results clearly show that T. cruzi induces apoptosis in the chorionic villi and suggest that this is one of mechanisms used by the parasite to insure infection and invasion of human placenta and fetus.
克氏锥虫引起的恰加斯病是拉丁美洲最常见的地方性疾病之一。尽管近年来克氏锥虫先天性传播已成为流行病学上的重要问题，但关于这种感染机制的研究却很少。胎盘组织在整个妊娠过程中都会发生凋亡，这是其正常更新的一部分。另一方面，已知克氏锥虫会诱导、延迟或抑制其他哺乳动物组织中的细胞凋亡。为了确定寄生虫入侵对胎盘正常凋亡的影响，将人绒毛膜绒毛外植体与 105 个锥虫滋养体孵育 24 小时。通过在组织学制剂中可视化克氏锥虫抗原和 PCR 来检测有效感染。感染后，通过光镜和透射电镜、TUNEL 分析、半胱天冬酶-3 样活性的测量以及半胱天冬酶 3 切割细胞角蛋白 18 的免疫组织化学检测来确定细胞凋亡。我们的研究结果清楚地表明，克氏锥虫诱导绒毛膜中的细胞凋亡，并提示这是寄生虫确保感染和入侵人胎盘和胎儿的机制之一。
