Author Correction: Maternal obesity-induced decreases in plasma, hepatic and uterine polyunsaturated fatty acids during labour is reversed through improved nutrition at conception.

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Maternal obesity-induced decreases in plasma, hepatic and uterine polyunsaturated fatty acids during labour is reversed through improved nutrition at conception.

Maternal obesity is associated with prolonged and dysfunctional labour, potentially through decreased synthesis of prostaglandins that stimulate myometrial contractions. We assessed the impact of maternal obesity on concentrations of precursor fatty acids (FA) for prostaglandin synthesis and whether any changes could be reversed by improved nutrition post-conception. Wistar rats were fed control (CON) or High-Fat, High-cholesterol (HFHC) diets 6 weeks before mating. At conception half the dams switched diets providing 4 dietary groups: (1) CON, (2) HFHC, (3) CON-HFHC or (4) HFHC-CON. During parturition rats were euthanized and FA composition of plasma, liver and uterus determined. Visceral fat was doubled in rats exposed to the HFHC diet prior to and/or during pregnancy compared to CON. HFHC diet increased MUFAs but decreased omega-3 and omega-6 PUFAs in plasma and liver. Uterine omega-3 FA concentrations were halved in HFHC versus CON rats, but all other FAs were similar. Switching from HFHC to CON diet at conception restored all FA profiles to those seen in CON rats. The increased MUFA and decreased PUFA concentrations in obese HFHC dams may contribute to aberrant prostaglandin synthesis and dysfunctional myometrial activity and it may be possible to reverse these changes, and potentially improve labour outcomes, by improving nutrition at conception.

Robust measurement of vitamin A status in plasma and blood dried on paper.

Vitamin A deficiency is the leading cause of preventable blindness in children and increases the risk of disease and death from severe infections. In addition, fat soluble vitamin A and associated retinoids directly regulate the expression of genes involved in fatty acid metabolism. Conventional methods for measuring vitamin A involve venipuncture, centrifugation and refrigeration all of which make measuring vitamin A in nutritional surveys expensive. We aimed to develop a simple and robust system for measurement of retinol (biomarker for vitamin A) using dried blood spot (DBS) samples. Low recoveries and inconsistent results reported by others were found to be due to poor extraction efficiency rather than retinol instability. Maintaining acid conditions during extraction resulted in recoveries >95% with <6.5% of coefficient of variation. Using isocratic high performance liquid chromatography, separation was achieved in <3.5 min. Detector response was linear (R(2)=0.9939) within a range of 0.05-2 µg/mL, with a limit of quantification of 0.05 µg/mL. Retinol in DBS was shown to be stable (>95%) at room temperature for up to 10 weeks. DBS values for retinol were highly correlated with venous blood samples from 24 healthy subjects (r=0.9724) and were consistent with results from a commercial laboratory. This simple and reliable method for the determination of vitamin A status should prove particularly valuable for population studies and large clinical trials.

A method for long term stabilisation of long chain polyunsaturated fatty acids in dried blood spots and its clinical application.

Conventional assays of omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in humans involve venous blood collection and expensive, multi-step processes that limit their usefulness as screening tools. This study aimed to develop a capillary dried blood spot (DBS) system capable of protecting n-3 LCPUFA from oxidation for up to 2 months at room temperature (20-25°C). We demonstrated that a DBS system comprising both an antioxidant and chelating agent on silica-gel coated paper prevented any significant change in the n-3 LCPUFA profile after 2 months. Our DBS assay was then tested in fifty subjects, and this demonstrated the presence of strong and significant correlations between the results obtained from the DBS system and those obtained from conventional measures for all fatty acids, in particular the n-3 LCPUFA EPA and DHA (r>0.96, P<0.0001). This study therefore validates our DBS system as a reliable method for the assessment of n-3 LCPUFA status in humans.