Stereological evaluation of vascular adaptations in human placental villi to differing forms of hypoxic stress

Burton, Graham J.; Reshetnikova, O.S.; Ap, Milovanov; Teleshova, O.

doi:10.1016/s0143-4004(05)80643-5

Cited by 138 publications

(77 citation statements)

References 17 publications

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“…The capillary:villus length ratio in control subjects was about 3.7 (0.12) km/km, equivalent to roughly two capillary loops per villus. In diabetic patients, the growth in length of capillaries tended to exceed the linear growth of villi and ratios [20,40]. In fact, capillary volumes and lengths are reduced [20].…”

Section: Resultsmentioning

confidence: 97%

“…In diabetic patients, the growth in length of capillaries tended to exceed the linear growth of villi and ratios [20,40]. In fact, capillary volumes and lengths are reduced [20]. High-altitude pregnancy could lead to hypercapillarization and decreases in vessel calibre but variable responses in terms of capillary volume and length [18,19,20].…”

Section: Resultsmentioning

confidence: 99%

“…High-altitude pregnancy could lead to hypercapillarization and decreases in vessel calibre but variable responses in terms of capillary volume and length [18,19,20]. In pre-eclampsia, capillarization is not altered but capillary volume is essentially conserved because decreases in capillary length are compensated by increases in calibre [20]. In GDM, capillary volume, length and calibre do not vary [25].…”

Section: Resultsmentioning

confidence: 99%

“…In preplacental hypoxia, the mother, placenta and fetus are hypoxic, there is excessive branching angiogenesis and growth of capillaries and villi is impoverished. This scenario accompanies maternal anaemia and pregnancy at high altitude [18,19,20]. In uteroplacental hypoxia, blood delivery to the maternal intervillous space is reduced and leads to more heterogeneous development of villi with a shift towards branching angiogenesis.…”

Section: Methodsmentioning

confidence: 99%

“…In uteroplacental hypoxia, blood delivery to the maternal intervillous space is reduced and leads to more heterogeneous development of villi with a shift towards branching angiogenesis. This picture is seen in pre-eclampsia and associated with a reduced total length, but conserved total volume, of capillaries [6,20]. In postplacental hypoxia, the mother is normoxic but the fetus is hypoxic and the placenta experiences 'relative hyperoxia' [21].…”

Section: Methodsmentioning

confidence: 99%

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Enhanced fetoplacental angiogenesis in pre-gestational diabetes mellitus: the extra growth is exclusively longitudinal and not accompanied by microvascular remodelling

Mayhew

2002

Diabetologia

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Aims/hypothesis. Morphometric studies on pregnancies complicated by gestational diabetes mellitus have found no evidence of increased fetoplacental angiogenesis. Here, placentas from control subjects and patients with pre-gestational Type I (insulin-dependent) diabetes mellitus were used to test for differences in measures of angiogenesis and vascular remodelling. Methods. Term placentas were collected from non-diabetic subjects and well-controlled diabetic patients grouped according to duration and severity into White classes B, C, D and F/R. Tissues were obtained by uniform random sampling for position and orientation. Volumes, surface areas and lengths of peripheral villi and their capillaries were estimated stereologically. Comparisons were drawn by analysis of variance and used to interpret mechanisms of growth, villous capillarization and vessel remodelling. Results. Placentas associated with all classes of diabetes contained greater (19-45%) volumes of fetal capillaries attributable solely to increases in the combined length of capillaries (12-47%) and not to alteration of vessel cross-sectional area or perimeter. Longitudinal growth tended to increase capillarization (capillary:villus length ratios up to 19% larger) but changes were inconsistent between diabetic classes. There was no evidence of altered vascular remodelling (cross-sectional shape factors, perimeter 2 /area, were preserved). Conclusions/interpretations. In well-controlled pre-gestational diabetes, fetoplacental angiogenesis is enhanced and occurs exclusively by longitudinal growth. Differences may involve hypoxic or other metabolic effects on endothelial cells, perivascular cells and angiogenic factors. The findings differ from those previously reported in gestational diabetes. No differences were associated exclusively with the presence of diabetic complications.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Enhanced fetoplacental angiogenesis in pre-gestational diabetes mellitus: the extra growth is exclusively longitudinal and not accompanied by microvascular remodelling

Mayhew

2002

Diabetologia

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Hypoxia and Placental Development

Soares

Iqbal

Kozai

2017

Birth Defects Research

116

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Hemochorial placentation is orchestrated through highly regulated temporal and spatial decisions governing the fate of trophoblast stem/progenitor cells. Trophoblast cell acquisition of specializations facilitating invasion and uterine spiral artery remodeling is a labile process, sensitive to the environment, and represents a process that is vulnerable to dysmorphogenesis in pathologic states. Hypoxia is a signal guiding placental development, and molecular mechanisms directing cellular adaptations to low oxygen tension are integral to trophoblast cell differentiation and placentation. Hypoxia can also be used as an experimental tool to investigate regulatory processes controlling hemochorial placentation. These developmental processes are conserved in mouse, rat, and human placentation. Consequently, elements of these developmental events can be modeled and hypotheses tested in trophoblast stem cells and in genetically-manipulated rodents. Hypoxia is also a consequence of a failed placenta, yielding pathologies that can adversely affect maternal adjustments to pregnancy, fetal health, and susceptibility to adult disease. The capacity of the placenta for adaptation to environmental challenges highlights the importance of its plasticity in safeguarding a healthy pregnancy.

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Maternal death and postpartum hemorrhage in sub‐Saharan Africa – A pilot study in metropolitan Mozambique

Lancaster

Barnes

Correia

et al. 2020

Research and Practice in Thrombosis and Haemostasis

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Background Maternal mortality in sub‐Saharan Africa is approximately 500 to 1000 per 100 000 births (vs. approximately 5‐20 in developed countries). Postpartum hemorrhage (PPH) is deemed responsible for 30% to 50% of the deaths. Objective To study PPH, risk factors, and mortality in metropolitan Mozambique to inform future studies and intervention strategies. Materials/Methods Retrospective cross‐sectional data extraction from all charts available to us (n = 495) recording deliveries between January and June 2018 at Maputo Central Hospital. Data included age, maternal survival, HIV status, parity, delivery mode, complications, vital signs, laboratory values, and maternal/fetal data. PPH was determined by charted diagnosis, interventions for hemorrhaging, placental abruption, transfusion, or blood loss. Autopsy reports from all deceased patients (n = 35) were examined. Results Median age was 29 years with 17% HIV prevalence. Risk factors for PPH (frequency, 12%) included parity (adjusted odds ratios (AORs) for 3+ versus nulliparity, 7.20 (95% confidence interval [CI], 2.46‐21.10), gestation length (AOR, 0.86; CI, 0.81‐0.92 per week), and body temperature (AOR, 1.10; CI, 1.04‐1.16 per 0.1°C). Maternal mortality was strongly associated with PPH (AOR, 5.22; 95% CI, 2.26‐12.08) and HIV (AOR, 11.66; 95% CI, 4.72‐28.78). Laboratory values (n = 241) were available from mothers experiencing complications (approximately 50%). Anemia (prevalence 54%) was a strong predictor of PPH with an inverse relationship between hemoglobin levels on admission (AOR, 0.62; 95% CI, 0.50‐0.77 per g/dL higher hemoglobin) and the probability of later suffering from PPH. Mothers who died following PPH had lower median hemoglobin (6.2 g/dL) than mothers who survived (9.2 g/dL). Protocols to estimate peripartum blood loss were not used; antifibrinolytics and/or cryoprecipitate were unavailable. Conclusion Postpartum hemorrhage is a serious problem even in metropolitan areas of sub‐Saharan Africa, and anemia influenced bleeding and death substantially. To address this problem, it is critical to raise awareness and region‐specific prevention and intervention protocols.

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Stereological evaluation of vascular adaptations in human placental villi to differing forms of hypoxic stress

Cited by 138 publications

References 17 publications

Enhanced fetoplacental angiogenesis in pre-gestational diabetes mellitus: the extra growth is exclusively longitudinal and not accompanied by microvascular remodelling

Enhanced fetoplacental angiogenesis in pre-gestational diabetes mellitus: the extra growth is exclusively longitudinal and not accompanied by microvascular remodelling

Hypoxia and Placental Development

Maternal death and postpartum hemorrhage in sub‐Saharan Africa – A pilot study in metropolitan Mozambique

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