Todros T, Sciarrone A, Piccoli E, Guiot C, Kaufmann P, Kingdom J
Department of Obstetrics and Gynaecology, University of Torino, Italy.
Obstet Gynecol. 1999 Apr;93(4):499-503. doi: 10.1016/s0029-7844(98)00440-2.
To test the hypothesis that the characteristics of umbilical artery Doppler flow velocity waveforms in growth-restricted fetuses indicate angiogenesis within placental stem and gas-exchanging villi.
We examined 18 placentas from singleton fetuses that were normal structurally and chromosomally but were growth-restricted, preterm, and complicated by preeclampsia. Ten cases with positive end-diastolic flow and eight with absent or reverse end-diastolic flow were compared with six gestational age-matched controls. Sections of villous placenta were examined to determine structural composition (percentage of fibrinoid, intervillous space, and villous tissue), relative proportion of villous types (stem, immature intermediate, and gas-exchanging villi), and the frequency distribution of stem arterial vessel calibers and their branching pattern.
Placentas with positive end-diastolic flow had a significantly (P < .05) higher percentage of gas-exchanging villi (median 69.6%, range 62.5-80.8%) than those with absent or reverse end-diastolic flow (58.3%, 29.9-71.9%) or controls (60.8%, 43.1-65.6%). The gas-exchanging villi from placentas with absent or reverse end-diastolic flow were slender, elongated, poorly branched, and poorly capillarized. There was a progressive trend toward reduced branching of the stem arteries from the controls (median 22%, range 2-38%), through the positive end-diastolic group (17%, 11-20%), to the absent or reverse end-diastolic group (13%, 4-23%).
Compared with absent or reverse end-diastolic flow, the placentas from growth-restricted fetuses with positive end-diastolic flow showed a normal pattern of stem artery development, accompanied by increased capillary angiogenesis and terminal villous development. These features suggest an adaptive pathway for the placenta in the face of uteroplacental ischemia.
验证以下假说，即生长受限胎儿脐动脉多普勒血流速度波形特征表明胎盘干绒毛和气体交换绒毛内存在血管生成。
我们检查了18例单胎胎儿的胎盘，这些胎儿在结构和染色体方面正常，但生长受限、早产且并发子痫前期。将10例舒张末期血流为正向的病例和8例舒张末期血流缺失或反向的病例与6例孕周匹配的对照进行比较。检查绒毛膜胎盘切片，以确定结构组成（纤维蛋白样物质、绒毛间隙和绒毛组织的百分比）、绒毛类型（干绒毛、未成熟中间绒毛和气体交换绒毛）的相对比例，以及干动脉血管口径及其分支模式的频率分布。
舒张末期血流为正向的胎盘，其气体交换绒毛的百分比（中位数69.6%，范围62.5 - 80.8%）显著高于（P < 0.05）舒张末期血流缺失或反向的胎盘（58.3%，29.9 - 71.9%）或对照胎盘（60.8%，43.1 - 65.6%）。舒张末期血流缺失或反向的胎盘的气体交换绒毛细长、拉长、分支少且毛细血管化程度低。从对照胎盘（中位数22%，范围2 - 38%）到舒张末期血流正向组（17%，11 - 20%），再到舒张末期血流缺失或反向组（13%，4 - 23%），干动脉分支逐渐减少。
与舒张末期血流缺失或反向相比，舒张末期血流为正向的生长受限胎儿的胎盘显示出正常的干动脉发育模式，伴有毛细血管生成增加和终末绒毛发育。这些特征提示胎盘面对子宫胎盘缺血时的一种适应性途径。
