Associations of blood levels of insulin-like growth factor (IGF)-I, IGF-II and IGF binding protein (IGFBP)-3 in schizophrenic Arab subjects

Background: Insulin-like growth factors (IGFs) are believed to be important in brain development and repair following neuronal damage. It is also speculated that IGFs are involved in the association of foetal and pre-adult growth with schizophrenia (SZ). Methods: The aim of this study was to assess levels of IGF-I, IGF-II and IGF binding protein (IGFBP)-3 and their associations in male Arab patients with SZ (n=53) and healthy control subjects (HC; n=52). Anthropometric and demographic data were collected for each subject for whom blood specimens were analysed for serum lipoproteins, apolipoprotein B (apoB), IGF-I, IGF-II and IGFBP-3. Results: The SZ group had lower serum total cholesterol, apoB and uric acid levels than the HC group (p < 0.05). IGF-II levels were significantly higher in the SZ group (p=0.02) and correlated positively with levels of atherogenic lipoproteins - total cholesterol, low-density lipoprotein, apoB - and IGFBP-3. The pattern of correlations between the IGFs and the various parameters differed somewhat between the HC and SZ groups. Conclusions: These results demonstrate that IGF-II levels are increased in patients with SZ and show significant associations with atherogenic lipoproteins. We suggest a possible link between IGF-II metabolism and atherogenesis in SZ.