Soma Hiroaki, Hata Toshio, Oguro Tatsuo, Fujita Koji, Kudo Motoshige, Vaidya Urmila
Department of Obstetrics & Gynecology, Saitama Medical School, 38 Morohongo, Moroyama-cho, Iruma-gun, Saitama, 350-0495, Japan.
Med Mol Morphol. 2005 Jun;38(2):92-103. doi: 10.1007/s00795-004-0259-y.
The placenta is an important functional unit for gas transfer between mother and fetus. The placental membrane, consisting of trophoblast layer interposed between maternal and fetal blood, plays an active role for intensity of respiration, but no morphological evidence has been documented. Until now, it has been reported that fetal growth retardation and increased fetal mortality rate usually could be seen at high altitude. In an attempt to find the cause of high perinatal mortality rate in Nepal, this study was undertaken to examine pathologically about 1000 Himalayan placentas obtained in Nepal and Tibet since 1977, and the results were compared with those of 5500 Japanese placentas at Saitama Medical School since 1990. In this study, characteristics of ultrastructural features of the Nepalese placental villi investigated in recent years are reported. (1) The gross characteristics of placental pathology in the Himalayan group were represented by marked subchorionic fibrin deposits and increased chorionic cysts in contrast to low incidence of intervillous thrombosis compared with those of the Japanese group. (2) As characteristics of histological findings of the placental villi between Himalayan and Japanese groups, the incidence of chorangiosis and chorangioma in the Himalayan group was significantly higher than that in the Japanese group. (3) Accompanying an increase of vasculosyncytial membrane (VSM) in the villi, thickness and separation of basement membrane of the syncytium in addition to increased apoptosis of syncytial cell nuclei were recognized. (4) As characteristic ultrastructural features of chorionic villi of Nepalese placentas, an increase of mitochondria and cystic formation of rough endoplasmic reticulum (rER), in addition to appearance of lamellar bodies similar to alveolar epithelial type II cell in organellae of the syncytium, were observed. These ultrastructural changes of the placental villous capillaries may be ascribed to hypervascularization caused by the chronic hypoxic state. It is, therefore, presumed that trophoblast cells may play an important role for gas transfer mechanism under such a hypoxic state at high altitude.
胎盘是母亲与胎儿之间进行气体交换的重要功能单位。胎盘膜由介于母血和胎儿血之间的滋养层组成，对呼吸强度起着积极作用，但尚无形态学证据。到目前为止，据报道在高海拔地区通常可见胎儿生长受限和胎儿死亡率增加。为了探寻尼泊尔围产期死亡率高的原因，本研究对自1977年以来在尼泊尔和西藏获得的约1000份喜马拉雅胎盘进行了病理学检查，并将结果与自1990年以来在埼玉医科大学获得的5500份日本胎盘的结果进行了比较。在本研究中，报告了近年来对尼泊尔胎盘绒毛超微结构特征的研究结果。（1）与日本组相比，喜马拉雅组胎盘病理学的总体特征表现为绒毛膜下纤维蛋白沉积明显和绒毛膜囊肿增多，而绒毛间血栓形成的发生率较低。（2）作为喜马拉雅组和日本组胎盘绒毛组织学发现的特征，喜马拉雅组绒毛血管增多症和绒毛血管瘤的发生率明显高于日本组。（3）随着绒毛中血管合体膜（VSM）的增加，除了合体细胞核凋亡增加外，还观察到合体细胞基底膜的厚度和分离。（4）作为尼泊尔胎盘绒毛膜绒毛的特征性超微结构特征，观察到线粒体增加、粗面内质网（rER）形成囊肿，此外在合体细胞的细胞器中还出现了类似于肺泡II型上皮细胞的板层小体。胎盘绒毛毛细血管的这些超微结构变化可能归因于慢性缺氧状态导致的血管增生。因此，推测滋养层细胞在高海拔这种缺氧状态下的气体交换机制中可能起重要作用。
