The l-arginine/nitric oxide pathway is impaired in overweight/obese pregnant women

L-Arginine supplementation in pregnancy: a systematic review of maternal and fetal outcomes

BACKGROUND/AIM OF THE STUDY

L-Arginine (L-Arg)/Nitric Oxide (NO) system is involved in the pathophysiology of relevant Obstetric conditions. This review aims at summarizing the effects of L-Arg supplementation in pregnancy looking at safety and efficacy.

METHODS

We conducted a systematic review of the literature utilizing PubMed for studies published from inception to September 2022. The search included human and animal studies where L-Arg was supplemented pre-conceptionally or during pregnancy, by either oral or intravenous route. The main perinatal outcomes were focused.

RESULTS

Among 1028 publications, 51 studies were eligible for inclusion, 25 were performed in women, and the remnant in animals. Compared to controls/placebo, the supplementation with L-Arg reduced the development of pre-eclampsia (four studies), decreased blood pressure, and reduced the need for antihypertensive drugs in women with Hypertensive Disorders of Pregnancy (HDP, eight studies). In women carrying growth retarded fetuses, L-Arg improved fetoplacental circulation, birth weight and neonatal outcomes (five studies), while in the case of threatened preterm birth, L-Arg reduced uterine contractions (two studies). In several animal species, L-Arg supplementation in pregnancy improved reproductive performance by increasing the litter number and size. Moreover, in pre-eclamptic and metabolic syndrome experimental models, maternal hypertension and fetal growth were improved.

CONCLUSION

L-Arg displays biological activities in pregnancies complicated by HDP and growth restriction, both in women and animal models. L-Arg administration is safe and could be a candidate as an intervention beneficial to maternal and fetal outcomes, at least in moderate clinical disorders.

Periconceptional biomarkers for maternal obesity: a systematic review

Periconceptional maternal obesity is linked to adverse maternal and neonatal outcomes. Identifying periconceptional biomarkers of pathways affected by maternal obesity can unravel pathophysiologic mechanisms and identify individuals at risk of adverse clinical outcomes. The literature was systematically reviewed to identify periconceptional biomarkers of the endocrine, inflammatory and one-carbon metabolic pathways influenced by maternal obesity. A search was conducted in Embase, Ovid Medline All, Web of Science Core Collection and Cochrane Central Register of Controlled Trials databases, complemented by manual search in PubMed until December 31^st, 2020. Eligible studies were those that measured biomarker(s) in relation to maternal obesity, overweight/obesity or body mass index (BMI) during the periconceptional period (14 weeks preconception until 14 weeks post conception). The ErasmusAGE score was used to assess the quality of included studies. Fifty-one articles were included that evaluated over 40 biomarkers. Endocrine biomarkers associated with maternal obesity included leptin, insulin, thyroid stimulating hormone, adiponectin, progesterone, free T4 and human chorionic gonadotropin. C-reactive protein was associated with obesity as part of the inflammatory pathway, while the associated one-carbon metabolism biomarkers were folate and vitamin B12. BMI was positively associated with leptin, C-reactive protein and insulin resistance, and negatively associated with Free T4, progesterone and human chorionic gonadotropin. Concerning the remaining studied biomarkers, strong conclusions could not be established due to limited or contradictory data. Future research should focus on determining the predictive value of the optimal set of biomarkers for their use in clinical settings. The most promising biomarkers include leptin, adiponectin, human chorionic gonadotropin, insulin, progesterone and CRP.

Comparison of brachial artery flow-mediated dilatation, uterine artery Doppler, and umbilical artery Doppler measurements in obese and normal pregnant women

OBJECTIVE

In this study, we aimed to compare vascular function at trimesters 1, 2, and 3 between obese and normal pregnant women through brachial artery flow-mediated dilatation (FMD), uterine artery Doppler, and umbilical artery Doppler measurements.

METHODS

Pregnant women between the ages of 18 and 40 who presented to our clinic were included. Brachial artery FMD, uterine and umbilical artery Doppler, and clinical parameters of 40 obese pregnant women from each trimester between 11 and 14 weeks, 24 and 28 weeks, 37 and 40 weeks and control pregnant group in the same number and gestational week were examined.

RESULTS

In all three trimesters, the FMD value was lower in obese pregnant women compared to normal women with adequate weight (p < 0.001). In obese pregnant women, lower FMD values were observed in the second trimester compared to other trimesters (p = 0.011) Cut-off value of FMD below 14.35 in obese pregnant women was found to be associated with gestational diabetes mellitus. Uterine artery Doppler in obese pregnant women started to increase from the second trimester compared to normal women with adequate weight.

CONCLUSION

Obese pregnant women have endovascular dysfunction compared to normal pregnant women and this becomes evident from the second trimester.

Dietary L-Arginine Intakes and the Risk of Metabolic Syndrome: A 6-Year Follow-Up in Tehran Lipid and Glucose Study

This study was conducted to investigate whether regular dietary intake of L-arginine could affect the occurrence of metabolic syndrome (MetS). Eligible adult men and women (n=1,237), who participated in the Tehran Lipid and Glucose Study, were followed for a median of 6.3 years. Dietary intakes of L-arginine and serum nitrate and nitrite (NOx) concentration were assessed at baseline (2006~2008), and demographics, anthropometrics, and biochemical variables were evaluated at baseline and follow-up examinations. The occurrence of MetS was assessed in relation to total L-arginine, intakes of L-arginine from animal and plant sources, with adjustment of potential confounding variables. Participants who had higher intake of L-arginine also had higher serum NOx at baseline (35.0 vs. 30.5 μmol/L, P<0.05). After 6 years of follow-up, higher intakes of L-arginine from animal sources were accompanied with increased risk of MetS [odd ratios (OR)=1.49, 95% confidence interval (95% CI)=1.02~2.18]. Compared to the lowest, the highest intakes of L-arginine from plant sources were related to significantly reduced risk of MetS (OR=0.58, 95% CI=0.32~0.99). In conclusion, our findings suggest a potentially protective effect of plant derived L-arginine intakes against development of MetS and its phenotypes; moreover, higher intakes of L-arginine from animal sources could be a dietary risk factor for development of metabolic disorders.

Oxidative stress biomarkers and their relationship with cytokine concentrations in overweight/obese pregnant women and their neonates

Background

Oxidative damage present in obese/overweight mothers may lead to further oxidative stress conditions or inflammation in maternal and cord blood samples. Thirty-four pregnant women/newborn pairs were included in this study to assess the presence of oxidative stress biomarkers and their relationship with serum cytokine concentrations. Oxidative stress biomarkers and antioxidant enzymes were compared between the mother/offspring pairs. The presence of 27 cytokines was measured in maternal and cord blood samples. Analyses were initially performed between all mothers and newborns and later between normal weight and mothers with overweight and obesity, and diabetic/non-diabetic women.

Results

Significant differences were found in biomarker concentrations between mothers and newborns. Additionally, superoxide-dismutase activity was higher in pre-pregnancy overweight mothers compared to those with normal weight. Activity for this enzyme was higher in neonates born from mothers with normal pregestational weight compared with their mothers. Nitrites in overweight/obese mothers were statistically lower than in their offspring. Maternal free fatty acids, nitrites, carbonylated proteins, malondialdehyde and superoxide dismutase predicted maternal serum concentrations of IL-4, IL-13, IP-10 and MIP-1β. Arginase activity in maternal plasma was related to decreased concentrations of IL-4 and IL-1β in cord arterial blood. Increased maternal malondialdehyde plasma was associated with higher levels of IL-6 and IL-7 in the offspring.

Conclusions

Oxidative stress biomarkers differ between mothers and offspring and can predict maternal and newborn cytokine concentrations, indicating a potential role for oxidative stress in foetal metabolic and immunologic programming. Moreover, maternal obesity and diabetes may affect maternal microenvironments, and oxidative stress related to these can have an impact on the placenta and foetal growth.

Biomarcadores de função endotelial em doenças cardiovasculares: hipertensão

A incidência de hipertensão arterial sistêmica está aumentando mundialmente. Sua prevenção baseia-se na identificação dos hipertensos. Atualmente, biomarcadores são utilizados com fins de diagnosticar, estratificar e prognosticar doenças. Neste estudo, objetivou-se revisar artigos dos últimos cinco anos relacionados a biomarcadores nas doenças cardiovasculares. Pesquisaram-se dados de PubMed, SciELO, Science Direct e MEDLINE, mediante as palavras-chave: hipertensão arterial, biomarcadores cardiovasculares, óxido nítrico, função endotelial e dimetilarginina assimétrica. Os estudos levantados mostram que as doenças cardiovasculares possuem uma etiologia complexa. Neste artigo, evidenciaram-se interações entre o óxido nítrico e a dimetilarginina assimétrica na regulação, no metabolismo e na determinação dos níveis intracelulares, e reviram-se outros biomarcadores relacionados à hipertensão. Alguns estudos indicam os biomarcadores como uma ferramenta útil na predição de eventos cardíacos, e outros reportam que eles contribuem pouco para a avaliação. A seleção e combinação desses pode ser uma alternativa para validar o uso dos biomarcadores devido à pouca especificidade existente para diagnosticar a hipertensão.

The Association of Dietary l-Arginine Intake and Serum Nitric Oxide Metabolites in Adults: A Population-Based Study

This study was conducted to investigate whether regular dietary intake of l-arginine is associated with serum nitrate + nitrite (NOx). In this cross-sectional study, 2771 men and women, who had participated in the third examination of the Tehran Lipid and Glucose Study (2006–2008), were recruited. Demographics, anthropometrics and biochemical variables were evaluated. Dietary data were collected using a validated 168-food item semi-quantitative food frequency questionnaire and dietary intake of l-arginine was calculated. To determine any association between dietary l-arginine and serum NOx, linear regression models with adjustment for potential confounders were used. Mean age of participants (39.2% men) was 45.9 ± 15.9 years. After adjustment for all potential confounding variables, a significant positive association was observed between l-arginine intake and serum NOx concentrations in the fourth quartile of l-arginine (β = 6.63, 95% CI = 4.14, 9.12, p for trend = 0.001), an association stronger in women. Further analysis, stratified by age, body mass index and hypertension status categories, showed a greater association in middle-aged and older adults (β = 9.12, 95% CI = 3.99, 13.6 and β = 12.1, 95% CI = 6.48, 17.7, respectively). l-arginine intakes were also strongly associated with serum NOx levels in overweight and obese subjects in the upper quartile (β = 10.7, 95% CI = 5.43, 16.0 and β = 11.0, 95% CI = 4.29, 17.5); a greater association was also observed between l-arginine intakes and serum NOx in non-hypertensive (HTN) compared to HTN subjects (β = 2.65, 95% CI = 2.1–3.2 vs. β = 1.25, 95% CI = −1.64–4.15). Dietary l-arginine intakes were associated to serum NOx and this association may be affected by sex, age, body mass index, and hypertension status.