1.
Retinol-binding protein 4, fetal overgrowth and fetal growth factors.
Yang, MN, Zhang, GH, Du, K, Wang, WJ, Dong, Y, He, H, Chiu, HC, Guo, YN, Ouyang, F, Zhang, J, et al
Pediatric research. 2020;(5):946-951
Abstract
BACKGROUND Retinol-binding protein 4 (RBP-4) is an adipokine involved in regulating insulin sensitivity which would affect fetal growth. It is unclear whether RBP-4 is associated with fetal overgrowth, and unexplored which fetal growth factor(s) may mediate the association. METHODS In the Shanghai Birth Cohort, we studied 125 pairs of larger-for-gestational-age (LGA, birth weight >90th percentile, an indicator of fetal overgrowth) and optimal-for-gestational-age (OGA, 25-75th percentiles) control infants matched by sex and gestational age. We measured cord blood concentrations of RBP-4, insulin, proinsulin, insulin-like growth factor-I (IGF-I), and IGF-II. RESULTS Cord blood RBP-4 concentrations were elevated in LGA vs. OGA infants (21.9 ± 6.2 vs. 20.2 ± 5.1 µg/ml, P = 0.011), and positively correlated with birth weight z score (r = 0.19, P = 0.003), cord blood proinsulin (r = 0.21, P < 0.001), IGF-I (r = 0.24, P < 0.001), and IGF-II (r = 0.15, P = 0.016). Adjusting for maternal and neonatal characteristics, each SD increment in cord blood RBP-4 was associated with a 0.28 (0.12-0.45) increase in birth weight z score (P < 0.001). Mediation analyses showed that IGF-I could account for 31.7% of the variation in birth weight z score in association with RBP-4 (P = 0.01), while IGF-II was not an effect mediator. CONCLUSIONS RBP-4 was positively associated with fetal overgrowth. IGF-I (but not IGF-II) may mediate this association.
2.
[Effect of IGF-1 on proliferation and differentiation of primary human embryonic myoblasts].
Cen, S, Zhang, J, Huang, F, Yang, Z, Xie, H
Zhongguo xiu fu chong jian wai ke za zhi = Zhongguo xiufu chongjian waike zazhi = Chinese journal of reparative and reconstructive surgery. 2008;(1):84-7
Abstract
OBJECTIVE To investigate the effect of IGF-1 on the growth of primary human embryonic myoblasts. METHODS The method of incorporation of 3H-TdR was used to evaluate the ability of proliferation of myoblasts. The count per minute (CPM) values of myoblasts at different concentrations (1, 2, 4, 8, 16 and 32 ng/mL) of IGF-1 were measured, and dose-effect curves were drawn to choose the optional concentration of IGF-1 to promote the proliferation. Then the experimental group of myoblasts received the addition of the optional concentration of IGF-1 in the growth medium, the control group just received the growth medium. The flow cytometry was used to detect the cell cycle. The method of incorporation of 3H-TdR was used to measure the peak-CPM. The myotube fusion rate was measured in myoblasts withdifferent concentrations (0, 5, 10, 15, 20, 25 and 30 ng/mL) of IGF-1 in fusion medium, the dose-effect curves were also drawn, so as to decided the optional concentration of IGF-1 in stimulating differentiation. Fusion medium with optional concentration of IGF-1 was used in experimental group, and the control group just with fusion medium. The fusion rate of myotube and the synthesis of creatine kinase (CK) were detected in both groups. RESULTS The optional concentration of 5 ng/mL IGF-1 was chosen for stimulating proliferation. It was shown that the time of cell cycle of control was 96 hours, but that of the experimental group was reduced to 60 hours. The results of flow cytometry showed that the time of G1 phase, S phase and G2M phase was 70.03, 25.01 and 0.96 hours respectively in control group, and were 22.66, 16.47 and 20.87 hours respectively in experimental group. The time-CPM value curves showed that the peak-CPM emerged at 96 hours in control group and 48 hours in experimental group, whichwas in agreement with the results of the flow cytometry. The optional concentration stimulating proliferation was 20 ng/mL IGF-1. Compared with control, the quantity of CK was increased by 2,000 mU/mL and the fusion rate was elevated by 30% in experimental group. CONCLUSION The concentrations of 20 ng/mL IGF-1 can elevat obviously the fusion rate and the quantity of CK. IGF-1 can enhance the proliferation and differentiation of myoblasts via inducing the number of myoblasts at G1 phase and increasing the number of myoblasts at S and G2M phases.