Potential biomarkers for fetal growth restriction : Measurements in different urine samples

Ritsema, P.E. (2017) Potential biomarkers for fetal growth restriction : Measurements in different urine samples. thesis, Medicine.

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Abstract

Background. Fetal growth restriction (FGR) occurs in about 10% of all human pregnancies and it often remains undiscovered until birth. One of the major causes of FGR is a poor placental health status and biomarkers may help to identify this. Both hydrogen sulfide (H2S, antioxidant, vasodilator and anti-inflammatory) and free thiols (involved in redox status) have the potential to be accurate biomarkers for FGR and can be easily derived from the urine. Whether urine H2S products and free thiols are alternated in pregnancy is unknown. The aim of this exploratory study is to define levels of urinary H2S and total free thiols in ‘normal’ pregnancy. Furthermore, it will be determined whether a 24-hour urine sample is representative for a first morning- or random urine sample with regard to levels of end products of H2S and total free thiols in both pregnant women and non-pregnant women. Methods. In this prospective cohort pilot study, 13 healthy women participated (of which 6 were pregnant and 7 non-pregnant), aged between 18 to 40 years. All subjects collected a first morning urine sample (A), 24-hour urine (B) and a random urine sample (C). Concentrations of total free thiols were analyzed, according to Ellman’s method. Mann-Whitney U test was used to determine differences between pregnant and non-pregnant women. Agreement between different urine samples was evaluated using Bland-Altman plots and Lin’s concordance correlation coefficient. Results. Median concentration of total free thiols in 24-hour urine samples (B) was significantly (p = 0.02) lower in pregnant women (14.4 μmol/L) when compared to non-pregnant women (37.4 μmol/L). There was no significant difference in samples A and C between groups. Lin’s concordance correlation coefficients showed a poor agreement among samples A and B, and samples C and B from the pregnant and non-pregnant group, respectively (with correlation coefficients of 0.25, 0.07, 0.09 and 0.63). Conclusion. The total free thiol concentration in 24-hour urine samples from pregnant women is lower than in 24-hour urine samples from non-pregnant women. This may point to redox changes in pregnant women. Furthermore, a first morning- or random urine sample does not seem to be representative for a 24-hour urine sample, with regard to concentrations of total free thiols. A further study will determine concentration levels of sulfate as main end product of H2S metabolism in both urine of healthy pregnancies and pregnant women diagnosed with FGR. In addition, it has to be further eexamined whether H2S and total free thiols are potential predictive biomarkers for FGR.

Item Type:	Thesis (Thesis)
Supervisor name:	Supervisor: and Gordijn, dr. S.J. and Department: Obstetrics & Gynaecology, UMCG
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:39
Last Modified:	25 Jun 2020 10:39
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/83

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