Concentration of cord serum placenta growth factor in normal and diabetic pregnancies

Metabolic abnormalities and obesity's impact on the risk for developing preeclampsia

Preeclampsia (PE), a hypertensive disorder of pregnancy, is increasing as a major contributor to perinatal and long-term morbidity of mother and offspring. PE is thought to originate from ischemic insults in the placenta driving the release of prohypertensive anti-angiogenic [soluble fms-like tyrosine kinase-1 (sFlt-1)] and proinflammatory [tumor necrosis factor-α (TNF-α)] factors into the maternal circulation. Whereas the increased incidence of PE is hypothesized to be largely due to the obesity pandemic, the mechanisms whereby obesity increases this risk are unknown. The maternal endothelium is targeted by placental and adipose tissue-derived factors like sFlt-1 and TNF-α that promote hypertension during pregnancy, resulting in vascular dysfunction and hypertension. Interestingly, not all obese pregnant women develop PE. Data suggest that obese pregnant women with the greatest metabolic abnormalities have the highest incidence of PE. Identifying obesity-related mechanisms driving hypertension in some obese pregnant women and pathways that protect normotensive obese pregnant women, may uncover novel protocols to treat PE. Metabolic abnormalities, such as increased circulating leptin, glucose, insulin, and lipids, are likely to increase the risk for PE in obese women. It is not only important to understand whether each of these metabolic factors contribute to the increased risk for PE in obesity, but also their cumulative effects. This is particularly relevant to obese pregnant women with gestational diabetes mellitus (GDM) where all of these factors are increased and the risk for PE is highest. It is speculated that these factors potentiate the anti-angiogenic and proinflammatory mechanisms of placental ischemia-induced vascular dysfunction thereby contributing to the increasing incidence of PE.

Time-specific placental growth factor (PlGF) across pregnancy and infant birth weight in women with preexisting diabetes

OBJECTIVE

Determine the independent association between time-specific placental growth factor (PIGF)-a marker of placental vasculature-and infant birth weight in offspring of mothers with preexisting type 1 and 2 diabetes.

METHODS

A total of 150 women were recruited from Joslin Diabetes Center's/Beth Israel Deaconess Medical Center's Diabetes in Pregnancy Program. PlGF was measured up to four times during pregnancy. Infant birth weight and covariate data were collected from medical records. Hemoglobin A1c was assessed from drawn blood samples. We used generalized linear and log-binomial models to calculate the change in continuous birth weight, as well as macrosomia for every unit change in time-specific ln-transformed PlGF, respectively. Models were adjusted for potential confounders.

RESULTS

Approximately 75% of women had type 1 diabetes. Third trimester PlGF levels were significantly associated with infant birth weight (r = 0.24, p = 0.02 at 27-34 weeks; r = 0.26, p < 0.009 for 36-40 weeks). After full adjustment, there was a 6.1% and 6.6% increase in birth weight for gestational age percentile for each unit increase in ln-transformed PlGF level at 27-34 weeks and 35-40 weeks, respectively (95% CI for 27-34 weeks gestation: 1.1, 11.0, and 95% CI for 35-40 weeks gestation: 0.7%, 12.5%). We found a statistically significant increased risk of macrosomia among women with higher ln-transformed PlGF levels (RR: 1.72; 95% CI: 1.09, 2.70). Associations were not mediated by hemoglobin A1c.

CONCLUSIONS

Third trimester PlGF levels were associated with higher birth weight in women with preexisting diabetes. These findings may provide insight to the pathophysiology of fetal overgrowth in women with diabetes.

First-Trimester Placental Growth Factor in Screening for Gestational Diabetes

OBJECTIVE

The aim of this study was first to assess whether first-trimester serum concentrations of placental growth factor (PlGF) differ between patients with and without gestational diabetes (GDM) and second to test whether there is a correlation between glycosylated hemoglobin (HbA1c), a factor recently shown to be useful in predicting GDM, and PlGF.

METHODS

PlGF was measured at 8-14 weeks with the Kryptor Immunoassay Analyzer (Brahms, Berlin, Germany). Absolute values were converted to multiples of the median using the software provided by the Fetal Medicine Foundation London. GDM was diagnosed using internationally accepted criteria. HbA1c levels were quantified using the TOSOH G7 automated hemoglobin analyzer.

RESULTS

From January to December 2014, 328 women were included in the study, 51 (15.5%) of whom developed GDM. First-trimester PlGF quantification does not discriminate between women at risk to develop GDM and controls, while HbA1c is able to do so. No correlation was found between PlGF and HbA1c.

CONCLUSION

Our findings do not lend support to the hypothesis that early PlGF values are different in women who later develop GDM.

Plasma vascular endothelial growth factor A and placental growth factor: novel biomarkers of pulmonary hypertension in congenital diaphragmatic hernia

Pulmonary hypertension (PH) due to abnormal pulmonary vascular development is an important determinant of illness severity in congenital diaphragmatic hernia (CDH). Vascular endothelial growth factor A (VEGFA) and placental growth factor (PLGF) may be important mediators of pulmonary vascular development in health and disease. This prospective study investigated the relationship between plasma VEGFA and PLGF and measures of pulmonary artery pressure, oxygenation, and cardiac function in CDH. A cohort of 10 infants with CDH consecutively admitted to a surgical neonatal intensive care unit (NICU) was recruited. Eighty serial plasma samples were obtained and analyzed by multiplex immunoassay to quantify VEGFA and PLGF. Concurrent assessment of pulmonary artery pressure (PAP) and cardiac function were made by echocardiography. Plasma VEGFA was higher and PLGF was lower in CDH compared with existing normative data. Combined plasma VEGFA:PLGF ratio correlated positively with measures of PAP, diastolic ventricular dysfunction, and oxygenation index. Nonsurvivors had higher VEGFA:PLGF ratio than survivors at days 3–4 of life and in the second week of life. These findings suggest that increased plasma VEGFA and reduced PLGF correlate with clinical severity of pulmonary vascular disease and may be associated with adverse outcome in CDH. This potential role for combined plasma VEGFA and PLGF in CDH as disease biomarkers, pathogenic mediators, and therapeutic targets merits further investigation.

Glucose, insulin, and oxygen interplay in placental hypervascularisation in diabetes mellitus

The placental vasculature rapidly expands during the course of pregnancy in order to sustain the growing needs of the fetus. Angiogenesis and vascular growth are stimulated and regulated by a variety of growth factors expressed in the placenta or present in the fetal circulation. Like in tumors, hypoxia is a major regulator of angiogenesis because of its ability to stimulate expression of various proangiogenic factors. Chronic fetal hypoxia is often found in pregnancies complicated by maternal diabetes as a result of fetal hyperglycaemia and hyperinsulinemia. Both are associated with altered levels of hormones, growth factors, and proinflammatory cytokines, which may act in a proangiogenic manner and, hence, affect placental angiogenesis and vascular development. Indeed, the placenta in diabetes is characterized by hypervascularisation, demonstrating high placental plasticity in response to diabetic metabolic derangements. This review describes the major regulators of placental angiogenesis and how the diabetic environment in utero alters their expression. In the light of hypervascularized diabetic placenta, the focus was placed on proangiogenic factors.

Pregnancy as the prodrome to vascular dysfunction and cardiovascular risk

In previously apparently healthy women, glucose intolerance and high blood pressure during pregnancy are common and frequently occur together. This article reviews the role of these gestational disorders as markers of vascular dysfunction and its pathophysiology. Mechanisms include alterations to function of large arteries and resistance vessels and to capillary blood flow. Much of the vessel pathology is seen in both gestational diabetes and hypertension. In women who have had transient diabetes during pregnancy and later redeveloped overt diabetes, cardiovascular risk is already elevated nearly fourfold before diagnosis, which is almost as high as the average risk after a clinical diagnosis of diabetes is made. This key finding suggests that vascular risk in such women is at least partly independent of overt hyperglycemia.