Relationships among maternal nutrient intake and placental biomarkers during the 1st trimester in low-income women

Alterations in Antioxidant Micronutrient Concentrations in Placental Tissue, Maternal Blood and Urine and the Fetal Circulation in Pre-eclampsia

Trace elements such as selenium and zinc are vital components of many enzymes, including endogenous antioxidants, and can interact with each other. Women with pre-eclampsia, the hypertensive disease of pregnancy, have been reported as having changes in some individual antioxidant trace elements during pregnancy, which are related to maternal and fetal mortality and morbidity. We hypothesised that examination of the three compartments of (a) maternal plasma and urine, (b) placental tissue and (c) fetal plasma in normotensive and hypertensive pregnant women would allow identification of biologically significant changes and interactions in selenium, zinc, manganese and copper. Furthermore, these would be related to changes in the angiogenic markers, placental growth factor (PlGF) and Soluble Fms-Like Tyrosine Kinase-1 (sFlt-1) concentrations. Venous plasma and urine were collected from healthy non-pregnant women (n = 30), normotensive pregnant controls (n = 60) and women with pre-eclampsia (n = 50) in the third trimester. Where possible, matched placental tissue samples and umbilical venous (fetal) plasma were also collected. Antioxidant micronutrient concentrations were measured by inductively coupled plasma mass-spectrometry. Urinary levels were normalised to creatinine concentration. Plasma active PlGF and sFlt-1 concentrations were measured by ELISA. Maternal plasma selenium, zinc and manganese were all lower in women with pre-eclampsia (p < 0.05), as were fetal plasma selenium and manganese (p < 0.05 for all); maternal urinary concentrations were lower for selenium and zinc (p < 0.05). Conversely, maternal and fetal plasma and urinary copper concentrations were higher in women with pre-eclampsia (p < 0.05). Differences in placental concentrations varied, with lower overall levels of selenium and zinc (p < 0.05) in women with pre-eclampsia. Maternal and fetal PlGF were lower and sFlt-1 higher in women with pre-eclampsia; maternal plasma zinc was positively correlated with maternal plasma sFlt-1 (p < 0.05). Because of perceptions that early- and late-onset pre-eclampsia have differing aetiologies, we subdivided maternal and fetal data accordingly. No major differences were observed, but fetal sample sizes were small following early-onset. Disruption in these antioxidant micronutrients may be responsible for some of the manifestations of pre-eclampsia, including contributing to an antiangiogenic state. The potential benefits of mineral supplementation, in women with deficient intakes, during pregnancy to reduce pre-eclampsia remain an important area for experimental and clinical research.

Maternal nutritional risk factors for pre-eclampsia incidence: findings from a narrative scoping review

BACKGROUND

Pre-eclampsia is a leading cause of maternal mortality and morbidity that involves pregnancy-related stressors on the maternal cardiovascular and metabolic systems. As nutrition is important to support optimal development of the placenta and for the developing fetus, maternal diets may play a role in preventing pre-eclampsia. The purpose of this scoping review is to map the maternal nutritional deficiencies and imbalances associated with pre-eclampsia incidence and discuss evidence consistency and linkages with current understandings of the etiology of pre-eclampsia.

METHODS

A narrative scoping review was conducted to provide a descriptive account of available research, summarize research findings and identify gaps in the evidence base. Relevant observational studies and reviews of observational studies were identified in an iterative two-stage process first involving electronic database searches then more sensitive searches as familiarity with the literature increased. Results were considered in terms of their consistency of evidence, effect sizes and biological plausibility.

RESULTS

The review found evidence for associations between nutritional inadequacies and a greater risk of pre-eclampsia. These associations were most likely mediated through oxidative stress, inflammation, maternal endothelial dysfunction and blood pressure in the pathophysiology of pre-eclampsia. Maternal nutritional risk factors for pre-eclampsia incidence with the strongest consistency, effect and biological plausibility include vitamin C and its potential relationship with iron status, vitamin D (both on its own and combined with calcium and magnesium), and healthy dietary patterns featuring high consumption of fruits, vegetables, whole grains, fish, seafood and monounsaturated vegetable oils. Foods high in added sugar, such as sugary drinks, were associated with increased risk of pre-eclampsia incidence.

CONCLUSION

A growing body of literature highlights the involvement of maternal dietary factors in the development of pre-eclampsia. Our review findings support the need for further investigation into potential interactions between dietary factors and consideration of nutritional homeostasis and healthy dietary patterns. Further research is recommended to explore gestational age, potential non-linear relationships, dietary diversity and social, cultural contexts of food and meals.

Associations between First Trimester Maternal Nutritional Score, Early Markers of Placental Function, and Pregnancy Outcome

This study investigated the associations between maternal adherence to a healthy diet, first trimester placental markers, and pregnancy outcome. Singleton spontaneous pregnancies were enrolled at 11⁺⁰-13⁺⁶ gestational weeks in a prospective cohort study. A nutritional score (0-10) measuring the adherence to a healthy diet was calculated. A transabdominal ultrasound scan for placental marker assessment was performed (uterine artery (UtA) doppler, placental volume). Biochemical placental markers were recorded (Pregnancy Associated Plasma Protein A (PAPP-A), free β- Human Chorionic Gonadotropin (HCG)). Birth outcomes were obtained from medical records. Associations between the maternal nutritional score, first trimester placental markers, and pregnancy outcome were investigated by using multi-adjusted general linear models. In total, 112 pregnancies were enrolled with a median nutritional score of 7 (range 3-10). Median gestational age at birth was 277 days (range 203-296). The nutritional score was positively associated with PAPP-A concentrations, whereas a negative association was detected with the UtA mean pulsatility index and placental volume. A positive association was detected between nutritional score and gestational age at birth. This study demonstrates that a first trimester nutritional score as a measure of adherence to a healthy diet is significantly associated with early biochemical and ultrasound markers of placental development, with further association with gestational age at birth.

The impact of periconceptional maternal lifestyle on clinical features and biomarkers of placental development and function: a systematic review

BACKGROUND

Worldwide, placenta-related complications contribute to adverse pregnancy outcomes, such as pre-eclampsia, fetal growth restriction and preterm birth, with implications for the future health of mothers and offspring. The placenta develops in the periconception period and forms the interface between mother and embryo/fetus. An unhealthy periconceptional maternal lifestyle, such as smoking, alcohol and under- and over-nutrition, can detrimentally influence placental development and function.

OBJECTIVE AND RATIONALE

The impact of maternal lifestyle on placental health is largely unknown. Therefore, we aim to summarize the evidence of the impact of periconceptional maternal lifestyle on clinical features and biomarkers of placental development and function throughout pregnancy.

SEARCH METHODS

A comprehensive search in Medline, Embase, Pubmed, The Cochrane Library Web of Science and Google Scholar was conducted. The search strategy included keywords related to the maternal lifestyle, smoking, alcohol, caffeine, nutrition (including folic acid supplement intake) and body weight. For placental markers throughout pregnancy, keywords related to ultrasound imaging, serum biomarkers and histological characteristics were used. We included randomized controlled trials and observational studies published between January 2000 and March 2017 and restricted the analysis to singleton pregnancies and maternal periconceptional lifestyle. Methodological quality was scored using the ErasmusAGE tool. A protocol of this systematic review has been registered in PROSPERO International prospective register of systematic reviews (PROSPERO 2016:CRD42016045596).

OUTCOMES

Of 2593 unique citations found, 82 studies were included. The median quality score was 5 (range: 0-10). The findings revealed that maternal smoking was associated with lower first-trimester placental vascularization flow indices, higher second- and third-trimester resistance of the uterine and umbilical arteries and lower resistance of the middle cerebral artery. Although a negative impact of smoking on placental weight was expected, this was less clear. Alcohol use was associated with a lower placental weight. One study described higher second- and third-trimester placental growth factor (PlGF) levels after periconceptional alcohol use. None of the studies looked at caffeine intake. Adequate nutrition in the first trimester, periconceptional folic acid supplement intake and strong adherence to a Mediterranean diet, were all associated with a lower resistance of the uterine and umbilical arteries in the second and third trimester. A low caloric intake resulted in a lower placental weight, length, breadth, thickness, area and volume. Higher maternal body weight was associated with a larger placenta measured by ultrasound in the second and third trimester of pregnancy or weighed at birth. In addition, higher maternal body weight was associated with decreased PlGF-levels.

WIDER IMPLICATIONS

Evidence of the impact of periconceptional maternal lifestyle on placental health was demonstrated. However, due to poorly defined lifestyle exposures and time windows of investigation, unstandardized measurements of placenta-related outcomes and small sample sizes of the included studies, a cautious interpretation of the effect estimates is indicated. We suggest that future research should focus more on physiological consequences of unhealthy lifestyle during the critical periconception window. Moreover, we foresee that new evidence will support the development of lifestyle interventions to improve the health of mothers and their offspring from the earliest moment in life.

Vitamin D restores angiogenic balance and decreases tumor necrosis factor-α in a rat model of pre-eclampsia

AIM

Deficiency of vitamin D is correlated with pre-eclampsia (PE), a hypertensive disorder of pregnancy, and is characterized by angiogenic imbalance and inflammation. The aim of this study was to investigate whether vitamin D supplementation can restore the angiogenic balance and ameliorate inflammation in a rat model of PE.

METHODS

PE was induced using l-nitroarginine methylester. Normal pregnant and PE-induced rats were supplemented with vitamin D on gestation days 14-19.

RESULTS

Blood pressure was significantly increased in PE-induced rats compared with normal pregnant rats (P < 0.05), and vitamin D supplementation ameliorated this difference. In addition, rats from the PE group had lower vascular endothelial growth factor (VEGF; P < 0.01), and higher plasma-soluble FMS-like tyrosine kinase-1 (sFlt-1) and tumor necrosis factor-α (TNF-α; P < 0.01 for both) compared with the normal pregnant group. The vitamin D treatment group had significantly increased VEGF, and reduced sFlt-1 and TNF-α compared with the untreated PE group. Moreover, vitamin D supplementation was able to reduce the oxidative stress by lowering the plasma oxidative stress marker malondialdehyde.

CONCLUSION

Vitamin D supplementation plays an important role in restoring angiogenic balance and reducing inflammation in pregnancy-induced hypertension.

Correlations among antiangiogenic factors and trace elements in hypertensive disorders of pregnancy

Although a number of studies have measured circulating levels of some trace elements in preeclampsia (PE) and compared to healthy pregnant (HP), there is no consensus yet about the deficiency of some metals and development of hypertensive disorders in pregnancy. The aim of this study was to compare plasmatic levels of Zn, Mn, Co, Cu, Se and Sr among non-pregnant (NP), healthy pregnant (HP), gestational hypertensive (GH) and preeclamptic (PE) women and to correlate these levels with plasma soluble endoglin (sENG) and soluble fms-like tyrosine kinase-1 (sFLT-1), two important antiangiogenic proteins related to PE. A total of 184 women were enrolled in this study (NP=35, GH=51, PE=37 and HP=61). Trace element analyses were carried out with an inductively coupled plasma mass spectrometer (ICPMS). sENG and sFLT-1 plasma concentrations were measured by commercial ELISA kits. The most interesting result is that Sr is higher in PE (63%, P<0.001) compared to HP and their levels are positively correlated with sENG in all three groups of pregnant women. Moreover, we found a negative correlation between Zn and sENG in HP (r=-0.43, P=0.003). Regarding other elements, we found similar levels among pregnant groups. In conclusion, this study showed that Sr may has a role in physiopathology of PE.

A combined supplementation of omega-3 fatty acids and micronutrients (folic acid, vitamin B12) reduces oxidative stress markers in a rat model of pregnancy induced hypertension

Objectives

Our earlier studies have highlighted that an altered one carbon metabolism (vitamin B₁₂, folic acid, and docosahexaenoic acid) is associated with preeclampsia. Preeclampsia is also known to be associated with oxidative stress and inflammation. The current study examines whether maternal folic acid, vitamin B₁₂ and omega-3 fatty acid supplementation given either individually or in combination can ameliorate the oxidative stress markers in a rat model of pregnancy induced hypertension (PIH).

Materials and Methods

Pregnant Wistar rats were assigned to control and five treatment groups: PIH; PIH + vitamin B₁₂; PIH + folic acid; PIH + Omega-3 fatty acids and PIH + combined micronutrient supplementation (vitamin B₁₂ + folic acid + omega-3 fatty acids). L-Nitroarginine methylester (L-NAME; 50 mg/kg body weight/day) was used to induce hypertension during pregnancy. Blood Pressure (BP) was recorded during pregnancy and dams were dissected at d20 of gestation.

Results

Animals from the PIH group demonstrated higher (p<0.01 for both) systolic and diastolic BP; lower (p<0.01) pup weight; higher dam plasma homocysteine (p<0.05) and dam and offspring malondialdehyde (MDA) (p<0.01), lower (p<0.05) placental and offspring liver DHA and higher (p<0.01) tumor necrosis factor–alpha (TNF–ά) levels as compared to control. Individual micronutrient supplementation did not offer much benefit. In contrast, combined supplementation lowered systolic BP, homocysteine, MDA and placental TNF-ά levels in dams and liver MDA and protein carbonyl in the offspring as compared to PIH group.

Conclusion

Key constituents of one carbon cycle (folic acid, vitamin B₁₂ and DHA) may play a role in reducing oxidative stress and inflammation in preeclampsia.

First trimester dietary intake, biochemical measures, and subsequent gestational hypertension among nulliparous women

INTRODUCTION

The purpose of this study was to evaluate the relationships between first-trimester dietary factors and biochemical measures and subsequent risk of gestational hypertension.

METHODS

This pilot study used a prospective design utilizing a convenience sample of nulliparous women enrolled at their first prenatal visit. A total of 57 women completed the study. Participants were divided into 2 groups for data analysis: normotensive pregnancy and gestational hypertension.

RESULTS

Nearly one-quarter of study participants (22.8%) developed gestational hypertension, of whom 84.6% had significant proteinuria meeting the criteria for preeclampsia. There were no significant differences in micronutrient or macronutrient dietary intakes between groups. Serum iron and zinc levels were lower for the gestational hypertension group compared with the normotensive pregnancy group (P ≤ .01). Low serum zinc levels were related to a risk of developing gestational hypertension (adjusted odds ratio, 0.930; 95% confidence interval, 0.872-0.992).

DISCUSSION

Ensuring adequate intake of zinc and monitoring serum zinc levels in nulliparous pregnant women may help to prevent or contribute to early detection of gestational hypertension.