ABSTRACT
INTRODUCTION: The aim of this systematic review and meta-analysis was to evaluate fetal cardiac function in fetuses of mothers with diabetes compared to those of mothers without diabetes using 2D-STE. METHODS: Embase, MEDLINE and CENTRAL were searched for observational studies on 2D-STE fetal left and right ventricular global longitudinal strain and strain rate that included singleton, non-anomalous pregnancies complicated by pregestational or gestational diabetes mellitus compared to uncomplicated pregnancies. The strain values were pooled per 4 weeks of gestation for meta-analysis using random-effects models. RESULTS: Fifteen studies met the criteria, including 990 fetuses of diabetic mothers and 1,645 control fetuses. The study design was cross-sectional in fourteen studies and longitudinal in one study. Gestational age, type of diabetes, ultrasound device and 2D-STE software varied between the studies. Glycemic control and type of treatment were often lacking. In fetuses of diabetic mothers versus healthy mothers, left ventricular strain was significantly decreased (7 studies), increased (1 study) or not significantly different (7 studies). Right ventricular strain was decreased (7 studies), increased (1 study) or not different (2 studies). Left ventricular strain rate was decreased (3 studies), increased (1 study) or not different (2 studies). Right ventricular strain rate was increased (1 study) or not different (2 studies). CONCLUSION: Fetuses of mothers with diabetes show evidence of systolic dysfunction, which is more visible in the right ventricle. Contradictory results are probably due to suboptimal study designs and variation in gestational age, diabetes severity, image acquisition and software. Large prospective longitudinal studies are needed to assess fetal myocardial function with 2D-STE in pregestational diabetes mellitus type 1 and 2 and gestational diabetes mellitus pregnancies. The influence of glycemic control, BMI and treatment should be evaluated.
ABSTRACT
Consumption of nitrate-rich beetroot juice (BRJ) by athletes induces a number of beneficial physiological health effects, which are linked to the formation of nitric oxide (NO) from nitrate. However, following a secondary pathway, NO may also lead to the formation of N-nitroso compounds (NOCs), which are known to be carcinogenic in 39 animal species. The extent of the formation of NOCs is modulated by various other dietary factors, such as vitamin C. The present study investigates the endogenous formation of NOCs after BRJ intake and the impact of vitamin C on urinary NOC excretion. In a randomized, controlled trial, 29 healthy recreationally active volunteers ingested BRJ with or without additional vitamin C supplements for one week. A significant increase of urinary apparent total N-nitroso Compounds (ATNC) was found after one dose (5 to 47 nmol/mmol: p < 0.0001) and a further increase was found after seven consecutive doses of BRJ (104 nmol/mmol: p < 0.0001). Vitamin C supplementation inhibited ATNC increase after one dose (16 compared to 72 nmol/mmol, p < 0.01), but not after seven daily doses. This is the first study that shows that BRJ supplementation leads to an increase in formation of potentially carcinogenic NOCs. In order to protect athlete's health, it is therefore important to be cautious with chronic use of BRJ to enhance sports performances.
