Schutte, A.E.Schutte, R.Smith, W.Huisman, H.W.Mels, C.M.C.Malan, L.Fourie, C.M.T.Malan, N.T.Van Rooyen, J.M.Kruger, R.2016-06-062016-06-062014Schutte, A.E. et al. 2014. Compromised bioavailable IGF-1 of black men relates favourably to ambulatory blood pressure: the SABPA study. Atherosclerosis, 233(1):139-144. [http://www.elsevier.com/locate/atherosclerosis]0021-91501879-1484 (Online)http://hdl.handle.net/10394/17609http://dx.doi.org/10.1016/j.atherosclerosis.2013.12.025https://pubmed.ncbi.nlm.nih.gov/24529134/https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.998.5588&rep=rep1&type=pdfObjectives Insulin-like growth factor-1 (IGF-1) has potent endothelial-protective, anti-platelet and anti-thrombotic activities, and also exerts mitogenic and proliferatory actions on vascular smooth muscle cells. Conflicting reports exist regarding the role of IGF-1 in vascular protection and atherogenesis. We therefore investigated the relationships of ambulatory blood pressure (BP) and carotid intima-media thickness (cIMT) with a range of components of the IGF-1 axis in a bi-ethnic population. Methods We included black (N = 86) and white (N = 101) men and measured growth hormone, total IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3), and pregnancy-associated plasma protein-A (PAPP-A) levels. Results Ambulatory BP was almost 10 mmHg higher in black men (137/88 mmHg versus 128/80 mmHg; both p < 0.001), accompanied by an adverse profile of the IGF-axis for all measured components (all p < 0.01), including reduced bioavailable IGF-1 (IGF-1/IGFBP-3; p = 0.006) and tissue IGF-1 accessibility index as represented by IGF-1.PAPP-A/IGFBP-3 (p < 0.001). Single, partial and multiple regression analyses confirmed an independent inverse association between ambulatory systolic BP and bioavailable IGF-1 in black men (R2 = 0.24; β = −0.22; p = 0.035). cIMT was similar in the ethnic groups (p = 0.34), and was negatively associated with bioavailable IGF-1 in white men (R2 = 0.42; β = −0.17; p = 0.039) prior to adjustment for γ-glutamyl transferase (R2 = 0.45; β = −0.10; p = 0.25). Conclusion Ambulatory systolic BP is inversely related to bioavailable IGF-1 in black men who displayed low IGF-1 concentrations. An inverse relation was found between cIMT and IGF-1 in white men, which disappeared after correction for γ-glutamyl transferase – opposing reports of a detrimental role of IGF-1 in the early stages of atherogenesis.eninsulin-like growth factor-1insulin-like growth factor binding protein-3growth hormonepregnancy-associated plasma protein-AAfricanblackatherosclerosisambulatory blood pressureArticle