CD34+ cells during recombinant human GH replacement in GH deficient adults

Adult patients with growth hormone deficiency have been shown to have a higher risk of cardiovascular morbidity, which can lead to death. Biomarkers for cardiovascular disease include endothelial function, vascular stiffness and low circulating CD34+ cells. In this clinical study by van der Klaauw et al., vascular structure and function were studied in relation to circulating CD34+ cells in growth hormone deficient adults before and during 1 year of treatment with recombinant human growth hormone (rhGH) replacement. Fourteen confirmed GHD adults (nine men, five women) were assessed for vascular function (by flow-mediated dilation) and structure (by pulse wave velocity). In addition the number of circulating CD34+ cells was measured using flow cytometric analysis. Measurements were taken before initiation of treatment with rhGH injections given subcutaneously every evening, and at 6 and 12 months of treatment.

The results showed that rhGH replacement increased both IGF-I levels and flow-mediated diameter over the course of treatment, while no effects were seen on pulse wave velocity. The number of CD34+ cells increased from 794.9 ±798.8 at baseline to 1270.7±580.1 cells/ml at 6 months, and 1356.9±759.0 at 12 months. The study represents a novel finding showing the beneficial effects of rhGH treatment on circulating CD34+ cells and endothelial function, seen within 6 months of treatment and maintained over the further 6 months. The authors suggest that rhGH treatment could be used to benefit vasculature in GHD adults. van der Klaauw, A.A., Pereira, A.M., Rabelink, T.J., Corssmit, E.P.M., Zonneveld, A-J., Pijl, H., de Boer, H.C., Smit, J.W.A., Romijn, J.A., de Koning, E.J.P. European Journal of Endocrinology 159, 105-111 10.1530/EJE-08-0179