Analysis of circulating insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) in tobacco smokers and non-smokers

Intrauterine smoke exposure deregulates lung function, pulmonary transcriptomes, and in particular insulin-like growth factor (IGF)-1 in a sex-specific manner

Prenatal exposure to tobacco smoke is a significant risk-factor for airway disease development. Furthermore, the high prevalence of pregnant smoking women requires the establishment of strategies for offspring lung protection. Therefore, we here aimed to understand the molecular mechanism of how prenatal smoke exposure affects fetal lung development. We used a mouse model recapitulating clinical findings of prenatally exposed children, where pregnant mice were exposed to smoke until c-section or spontaneous delivery, and offspring weight development and lung function was monitored. Additionally, we investigated pulmonary transcriptome changes in fetal lungs (GD18.5) by mRNA/miRNA arrays, network analyses and qPCR. The results demonstrated that prenatally exposed mice showed intrauterine and postnatal growth retardation, and impaired lung function. 1340 genes and 133 miRNAs were found to be significantly dysregulated by in utero smoke exposure, and we identified Insulin-like growth factor 1 (Igf1) as a top hierarchical node in a network analysis. Moreover, Igf1 mRNA was increased in female murine offspring and in prenatally exposed children. These findings suggest that prenatal smoking is associated with a dysregulation of several genes, including Igf1 in a sex-specific manner. Thus, our results could represent a novel link between smoke exposure, abberant lung development and impaired lung function.

Insulin-like growth factor 1 myocardial expression decreases in chronic alcohol consumption

Background

Alcoholic cardiomyopathy (CMP) is one of the major complications of chronic excessive alcohol consumption. The pathogenic mechanisms implicated are diverse, inducing functional and structural changes in the myocardium. Insulin-like Growth Factor 1 (IGF-1) plays an important role in modulating the cell cycle, and helps the differentiation and proliferation of cardiac tissue inhibiting apoptosis. Experimental studies have suggested the role of IGF-1 in alcohol-induced cardiac damage. The aim of the present study was to determine the effect of chronic alcohol consumption on IGF-1 myocardial expression and to compare this expression in cases of hypertension and other cardiac diseases.

Methods

We studied heart samples from human organ donors: 10 healthy donors, 16 with hypertension, 23 with chronic alcohol consumption and 7 with other causes of cardiac disease. IGF-1 myocardial expression was evaluated with a specific immunohistochemistry assay using a semi-quantitative method.

Results

A significant decrease in IGF-1 myocardial expression was observed comparing all the cases included with control donors. This decrease in IGF-1 myocardial expression was significantly lower in the group of donors with chronic alcohol consumption compared to controls. On group evaluation according to the presence of CMP, donors with chronic alcohol consumption without CMP presented significantly lower IGF-1 expression than controls, whereas donors with chronic alcohol consumption with CMP showed a downward trend without achieving significance.

Conclusions

Chronic alcohol consumption significantly reduces IGF-1 myocardial expression. This decrease induced by alcohol is partially compensated in the presence of structural myocardial damage.