Abstract
Background
Excessive gestational weight gain (GWG) increases risk of large for gestational age neonates and subsequent tracking of excess weight throughout the life course for both mother and child. Although the physiological mechanisms underlying these associations are incomplete, the insulin-like growth factor (IGF) axis has garnered attention for its role in fetal growth and development. Our purpose was to characterize the IGF axis protein expression patterns in mother–infant dyads in respect of excessive GWG.
Methods
We obtained fasting serum samples and corresponding cord blood from eight controls (ADHERE group: ie, those who gained in accordance with 2009 Institute of Medicine GWG recommendations) and 13 exceeders (EXCEED group: ie, those who exceeded Institute of Medicine GWG recommendations). At study completion, we examined protein expression of IGF-I, IGF-II, IGF binding protein (IGFBP)-1, IGFBP-3, IGFBP-4, and hormone concentrations in both maternal and cord blood.
Results
Between-group comparisons were made and revealed elevated maternal leptin (P ≤ 0.05) concentrations in gravidas who exceeded recommendations. There was a significantly higher number of obese women in the EXCEED group (P < 0.05). After adjustment, maternal leptin levels were positively correlated with maternal homeostasis model of assessment for insulin resistance score and excessive GWG (P ≤ 0.01). However, serum IGFBP-3 expression in the EXCEED mothers was greater than that in the ADHERE group (P ≤ 0.05).
Conclusion
These findings provide preliminary evidence suggesting that small deviations in IGFBP-regulated IGF bioavailability arising from excessive GWG/positive energy balance may affect adipocyte differentiation through subclinical insulin resistance.
Acknowledgments
We are indebted to the Ottawa Hospital General Campus Labour and Delivery Team for their assistance with patient recruitment, and to Dr Nina Fowler for her assistance with laboratory assays. This work was supported by the University of Ottawa, Faculty of Health Sciences/Children’s Hospital of Eastern Ontario Research Partnership Grant awarded to KBA and ZMF and a W Garfield Weston Foundation Award in Obesity and Reproductive Health given to AG and KBA. The Ministry of Research and Innovation–Early Researcher Award (KBA) provided graduate funding for ZMF, who was also a recipient of an Ontario Graduate Scholarship from the Ontario Ministry of Training, Colleges, and Universities.
Author contributions
ZMF conceived the study, recruited the patients, collected the samples, ran the experiments, analyzed the data, and led manuscript drafting. QQ supervised the experiments and assisted with data analysis. AG assisted with study design, helped interpret the data, and critically reviewed the manuscript. KBA assisted with study design, data interpretation, and critical review of the manuscript. All authors drafted and/or revised, then approved the final manuscript.
Disclosure
The authors report no conflicts of interest in this work.