Separation of the molecular forms of the insulin-like growth factor (IGF)-Binding proteins by affinity chromatography

Technology-free predictors of preterm birth in singleton women with threatened preterm labor: a prospective cohort study

Background

Prediction of preterm birth is still a challenge due to its multiple etiologies. This prospective cohort study aimed to determine the technology-free predictors of preterm birth in singleton women with threatened preterm labor.

Methods

This prospective cohort study was performed on 371 singleton women with gestational age of 23^+ 6 to 36^+ 4 weeks hospitalized for threatened preterm labor. The data were collected using a questionnaire including demographic characteristics, medical and maternal history, as well as the Perceived Stress Scale (PSS), the Multidimensional Scale of Perceived Social Support (MSPSS), and the WHO’s questionnaire of Violence against Women (VAW). The participants were followed-up until childbirth. The predictors were determined using multivariate logistic regression.

Results

Preterm birth occurred in 51% of women. Seven variables were determined as predictors; rupture of membranes [adjusted odds ratio 11.7, 95% confidence interval 5.4 to 25.6], cervical dilation [AOR 4.1, 95% CI 2.0 to 7.0], gravidity ≥6 [AOR 27.4, 95%CI 2.8 to 264.3], psychological violence during pregnancy [AOR 2.0, 95% CI 1.1 to 3.2], medical problems in pregnancy onset [AOR 1.7, 95% CI 1.1 to 2.8], vaginal bleeding/spotting [AOR 2.1, 95% CI 1.2 to 4.0] and woman age ≤ 19 [AOR 2.2, 95% CI 1.1 to 4.5]. The proportion of variance explained by all these factors was 33.6%.

Conclusions

The technology-free factors seems to have moderate power in preterm birth prediction in singleton pregnant women hospitalized for threatened preterm labor. However, these results are discoveries without verification or validation and need to be confirmed by generalizable studies.

Insulin-like growth factor binding protein-1 in insulin resistance and cardiovascular disease

Insulin-like growth factors (IGFs) are peptide hormones that have significant structural homology with insulin. IGF binding proteins (IGFBPs), in particular IGFBP-1, are important determinants of IGF activity such as enhancing peripheral glucose uptake, decreasing hepatic glucose output and modifying lipid metabolism. Herein factors which alter IGFBP-1 and the utility of measuring IGFBP-1 are considered as the role of IGFBP-1 is explored within the context of insulin resistance and the development of cardiovascular disease.

Investigation of different molecular forms of IGFBP-1 using immobilised metal-, immuno- and lectin-affinity chromatography

Insulin-like growth factor-binding protein 1 (IGFBP-1) is a member of a family of six homologous proteins that regulate the action of the insulin-like growth factors. IGFBP-1 is a 25 kDa protein that beside its native form, may exist in several phosphoforms (30 kDa), which are predominant in the circulation of humans. Phosphorylation of IGFBP-1 is a post-translational modification that has a great influence on the IGF-I action. IGFBP-1 forms multimers and complexes with ?2-macroglobulin (?2M). Polymerisation of IGFBP-1 was also reported. In order to analyse and separate these IGFBP-1 molecular species, affinity chromatography methods were used in this study. The results demonstrated that most of the IGFBP-1 circulates in complexes with ?2M, which can be isolated by affinity chromatography using immobilised anti-?2M antibodies. IGFBP- 1/?2M complexes may be differentiated from IGFBP-1 dimer and multimers using lectin-affinity chromatography, since the latter do not interact with lectins. It seems that the complexes contain not only monomeric IGFBP-1, but also its multimers. Dimer and multimers are stable under reducing conditions, suggesting covalent linkage between units. Free IGFBP-1 monomer can be separated from multimers using Con A-affinity chromatography. The concentration of free IGFBP-1 is relatively low in the circulation.