The relationship between hair metabolites, air pollution exposure and gestational diabetes mellitus: A longitudinal study from pre-conception to third trimester

Abstract

BackgroundGestational diabetes mellitus (GDM) is a metabolic condition defined as glucose intolerance with first presentation during pregnancy. Many studies suggest that environmental exposures, including air pollution, contribute to the pathogenesis of GDM. Although hair metabolite profiles have been shown to reflect pollution exposure, few studies have examined the link between environmental exposures, the maternal hair metabolome and GDM. The aim of this study was to investigate the longitudinal relationship (from pre-conception through to the third trimester) between air pollution exposure, the hair metabolome and GDM in a Chinese cohort.MethodsA total of 1020 women enrolled in the Complex Lipids in Mothers and Babies (CLIMB) birth cohort were included in our study. Metabolites from maternal hair segments collected pre-conception, and in the first, second, and third trimesters were analysed using gas chromatography-mass spectrometry (GC-MS). Maternal exposure to air pollution was estimated by two methods, namely proximal and land use regression (LUR) models, using air quality data from the air quality monitoring station nearest to the participant’s home. Logistic regression and mixed models were applied to investigate associations between the air pollution exposure data and the GDM associated metabolites.ResultsOf the 276 hair metabolites identified, the concentrations of fourteen were significantly different between GDM cases and non-GDM controls, including some amino acids and their derivatives, fatty acids, organic acids, and exogenous compounds. Three of the metabolites found in significantly lower concentrations in the hair of women with GDM (2-hydroxybutyric acid, citramalic acid, and myristic acid) were also negatively associated with daily average concentrations of PM2.5, PM10, SO2, NO2, CO and the exposure estimates of PM2.5 and NO2, and positively associated with O3.ConclusionsThis study demonstrated that the maternal hair metabolome reflects the longitudinal metabolic changes that occur in response to environmental exposures and the development of GDM.

The maternal hair metabolome is capable of discriminating intrahepatic cholestasis of pregnancy from uncomplicated pregnancy

“…Hair samples were cut into three segments (each segment 3cm long). Previous studies have demonstrated that utilizing a 3 cm segmentation of the same hair strand is proficient in discriminating between pregnancy trimesters ( 20 , 21 ). Thus, the first segment (0-3 cm) represented the third trimester, and the next 0.5 cm hair segment was discarded.…”

Multigenerational diabetes mellitus

“…Significant heterogeneity exists between studies, including differences in sample type, timing of sample collection and sample size, making comparison between studies, and therefore establishment of meaningful conclusions, difficult. Diet, pharmacological treatment and environmental factors ( 48 ) also influence metabolite abundance, as well as genetic and epigenetic factors ( 49 ), further confounding comparability of findings. Metabolomic findings discussed in this review are summarized in Table 1 .…”

Critical Factors in Sample Collection and Preparation for Clinical Metabolomics of Underexplored Biological Specimens

“…For this reason, this specimen can be a good alternative for metabolomic studies, providing a broader view of the metabolic profile. Thus, in the last five years, hair samples have been widely used to study pregnancy complications, such as pre-eclampsia [ 127 ], fetal growth restriction [ 128 ], gestational T2DM [ 129 ], and diet restrictions [ 130 ]. Additional clinical investigations include the search for biomarkers in cervical cancer [ 131 ] and Alzheimer’s disease [ 132 , 133 ] and the monitoring of chronic conditions such as androgenetic alopecia [ 134 ] and baldness [ 135 ].…”

“…Metabolite extraction is performed with or without alkaline hydrolysis, using NaOH 4 mol L −1 [ 139 ] or, more frequently, KOH 1 mol L −1 , followed by neutralization with H 2 SO 4 (3 mol L −1 ) [ 127 , 128 , 131 ]. Proteins are usually precipitated by the addition of pure methanol [ 125 , 129 , 134 , 135 ], methanol/phosphate saline buffer (PBS) [ 132 , 133 , 140 ], or methanol/water/acetone (1:1:1, v / v / v ) [ 141 ]. In order to increase extraction performance, bench mills [ 142 , 143 ], ultrasound [ 132 , 133 ], and vortex [ 128 , 139 ] have been applied.…”