Short-term rhGH increases PIIINP, a biomarker of endothelial dysfunction

Objectives: In arterial hypertension, amino-terminal propeptide of type III procollagen (PIIINP) is elevated in arterial aneurysm tissue and associated with a poor prognosis following acute myocardial infarction (MI). Recombinant human growth hormone (rhGH) administration attenuates endothelial dysfunction but increases PIIINP. This study was conducted to establish if short-term rhGH administration affects PIIINP, endothelial function and selected cardiovascular disease (CVD) risk factors, in healthy males. 
Design: Method: Male subjects (n=48) were randomly assigned into two groups: (1): control group (C) n=24, mean ± SD, age 32 ± 11 years; height 1.8 ± 0.06 metres; (2): rhGH administration group (rhGH) n=24, mean ± SD, age 32 ± 9 years; height 1.8 ± 0.07 metres. Blood pressure (BP), heart rate (HR), arterial pulse wave velocity (APWV), and biochemical indices were investigated. 
Results: PIIINP (0.28±0.1 vs. 0.42±0.2, U/ml); Insulin like growth factor-I (159±54 vs. 323±93, ng·mL^-1); resting HR (72±14 vs. 78±11, b.p.m.) and rate pressure product (RPP) (90±18 vs. 97±14, bpm x mm·Hg x 10^-2) all significantly increased (P<0.05). Total cholesterol (4.7±0.9 vs. 4.4±0.7, mmol·L^-1); high sensitivity C-reactive protein (1.77±2.1 vs. 1.29±1.6, mg·L^-1); serum homocysteine (13.2±4.0 vs. 11.7±3.1, μmol·L^-1) and APWV (9.97±1.38 vs. 9.18±1.6, m·s^-1) all significantly decreased (P<0.05). 
Conclusion: Paradoxically, there was an improvement in CVD inflammatory markers and APWV; but PIIINP and resting RPP increased. Elevated PIIINP may have a confounding adverse effect on the endothelium, but may also provide clinical prognostic information in monitoring arterial hypertension, left ventricular function in the sub-acute phase following MI and endothelial function in aortic aneurysms.