Stereological study of the effect of altitude on the trophoblast cell populations of human term placental villi

Ali, K.Z.M.

doi:10.1016/s0143-4004(97)80046-x

Cited by 38 publications

(15 citation statements)

References 17 publications

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“…Alternatively, insulin extraction by the placenta may be increased at high altitude. The placenta at high altitude is larger, and the surface of the trophoblast villi, which contains the functional cells of the placenta, is greater than at sea level (22). In pregnancy at sea level, there is some evidence that this increased turnover may be the consequence of insulin degradation by the placenta (23), but several studies suggest that the extraction of insulin by the placenta in monotocous species (such as humans) may not be great enough to increase the fractional rate of maternal insulin turnover to a detectable degree (24).…”

Section: Proinsulinmentioning

confidence: 99%

Glucose Metabolism in Pregnancy at High Altitude

et al. 2001

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OBJECTIVE -To assess insulin sensitivity and ␤-cell function associated with lower maternal fasting plasma glucose levels at high altitude compared with sea level.RESEARCH DESIGN AND METHODS -We studied 215 pregnant women at 8 -42 weeks of gestation in Peru. The women were recruited from Cerro de Pasco, which is situated 4,370 m (14,340 feet) above sea level, and Lima, which is at sea level. We also examined 53 nonpregnant control subjects (22 in Cerro de Pasco and 31 in Lima). Fasting plasma glucose, insulin, C-peptide, and proinsulin concentrations were measured in samples obtained from the antecubital vein between 8:00 A.M. and 10:00 A.M. after an overnight period of fasting for 10 -14 h. Insulin resistance and ␤-cell function were calculated using homeostasis model assessment.RESULTS -Fasting C-peptide levels and ␤-cell function were similar, fasting concentrations of insulin and proinsulin were lower, and insulin sensitivity was higher at high altitude compared with sea level.CONCLUSIONS -Maternal fasting plasma glucose that is lower at high altitude than at sea level in the presence of similar insulin secretion is associated with higher peripheral insulin sensitivity. This may partly explain the lower birth weights at high altitudes.

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Section: Proinsulinmentioning

confidence: 99%

Glucose Metabolism in Pregnancy at High Altitude

et al. 2001

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“…Besides, a very recent study reported that the miR-130 family members, including miR-130a and miR-130b, the latter of which was also found to be upregulated in sPE plasma samples in this study, regulated HIF1a signaling via targeting P-body protein DDX6, which promoted the translation of HIF1a under hypoxia (Saito et al 2011). In addition, it has long been believed that cytotrophoblast proliferation is upregulated in low oxygen concentrations (Fox 1964), which is further supported by the phenomenon that there are increased numbers of cytotrophoblast cells in the placenta at high altitude (Ali 1997), indicating the cell cycle is altered in preeclamptic placenta. However, more investigation is required to determine the mechanisms whereby the seven circulating miRNAs were elevated in sPE.…”

Section: Discussionmentioning

confidence: 94%

Circulating microRNAs are elevated in plasma from severe preeclamptic pregnancies

Zhou²,

Lin³

et al. 2012

Reproduction

173

137

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Until recently, the molecular pathogenesis of preeclampsia (PE) remained largely unknown. Reports have shown that circulating microRNAs (miRNAs) are promising novel biomarkers for cancer, pregnancy, tissue injury, and other conditions. The objective of this study was to identify differentially expressed miRNAs in plasma from severe preeclamptic pregnancies compared with plasma from normal pregnancies. By mature miRNA microarray analysis, 15 miRNAs, including 13 up-and two downregulated miRNAs, were screened to be differentially expressed in plasma from women with severe PE (sPE). Seven miRNAs, namely miR-24, miR-26a, miR-103, miR-130b, miR-181a, miR-342-3p, and miR-574-5p, were validated to be elevated in plasma from severe preeclamptic pregnancies by real-time quantitative stem-loop RT-PCR analysis. Gene ontology and pathway enrichment analyses revealed that these miRNAs were involved in specific biological process categories (including regulation of metabolic processes, regulation of transcription, and cell cycle) and signaling pathways (including the MAP kinase signaling pathway, the transforming growth factor-b signaling pathway, and pathways in cancer metastasis). This study presents, for the first time, the differential expression profile of circulating miRNAs in sPE patients. The seven elevated circulating miRNAs may play critical roles in the pathogenesis of sPE, and one or more of them may become potential markers for diagnosing sPE.

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“…Maintaining metabolism at a low level during blastocyst development improves pregnancy outcome (Leese, 2002), and it would appear that the same may apply during the phase of organogenesis. Experimental data also suggest that a low oxygen environment is necessary to maintain human embryonic stem cells in a pluriopotent state (Ezashi et al, 2005), and for promoting proliferation of cytotrophoblast cells, both in vitro and in vivo (Fox, 1964;Genbacev et al, 1996;Ali, 1997). Daughter cells may then feed through into either the villous or extravillous trophoblast population.…”

Section: Introductionmentioning

confidence: 99%

The influence of the intrauterine environment on human placental development

Jauniaux²,

2010

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Development of the human placenta is modulated heavily by the intrauterine environment. During the first trimester, development takes place in a low oxygen environment supported by histiotrophic nutrition from the endometrial glands. Consequently, the rate of growth of the chorionic sac is almost invariable across this period, and is remarkably uniform between individuals. Towards the end of the first trimester the intrauterine environment undergoes radical transformation in association with onset of the maternal arterial circulation and the switch to haemotrophic nutrition. The accompanying rise in intraplacental oxygen concentration poses a major challenge to placental tissues, and extensive villous remodelling takes place at this time. Later in pregnancy a wide variety of stressors are capable of affecting placental growth, but in the human, the most common are nutrient deprivation and vascular compromise. The latter is usually secondary to deficient trophoblast invasion and can induce placental oxidative stress. Closely linked to oxidative stress is endoplasmic reticulum stress, and we recently provided the first evidence that the latter plays a major role in the pathophysiology of intrauterine growth restriction. The endoplasmic reticulum is a key regulator of protein synthesis, exerting its effects through the unfolded protein response. Consequently, we observed multiple blocks to translation initiation and elongation in growth restricted placentas. Nutrient deprivation also modulates protein synthesis through the mTOR pathway, and we demonstrated interactions between this pathway and endoplasmic reticulum stress. Protein synthesis inhibition therefore appears to be a common mechanism for regulating placental development under different adverse conditions.

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Stereological study of the effect of altitude on the trophoblast cell populations of human term placental villi

Cited by 38 publications

References 17 publications

Glucose Metabolism in Pregnancy at High Altitude

Glucose Metabolism in Pregnancy at High Altitude

Circulating microRNAs are elevated in plasma from severe preeclamptic pregnancies

The influence of the intrauterine environment on human placental development

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