1.
Radioidine therapy temporarily increases circulating endothelial cells and decreases endothelial progenitor cells.
Palumbo, B, Palumbo, R, Sinzinger, H
Nuclear medicine review. Central & Eastern Europe. 2003;(2):123-6
Abstract
BACKGROUND Radiotherapy can cause vascular injury. No data on radioiodine therapy and vascular damage are available. MATERIAL AND METHODS We examined the number of circulating endothelial cells (CEC) and circulating endothelial progenitor cells (CEPC) before therapy 1, 2, 3 and 5 days as well as 1, 2, 3, 4, 6, 8, 10, and 12 weeks after therapy with (131)I at doses ranging from 5-200 mCi. The individual number of CEC and CEPC is associated with the presence of risk factors. RESULTS Irrespective of prevalues, CEC exhibited a significant dose-dependent temporary increase reaching the maximum in weeks 1 and 2. In contrast, CEPC show a decrease at the same time. CONCLUSIONS These results indicate that (131)I-therapy induces a dose-dependent radiation injury at the vascular wall level enhancing endothelial desquamation and reducing reendothelialization and thereby a proatherogenic stage. The clinical consequence of these findings still needs to be assessed.
2.
Mobilization of endothelial progenitor cells in patients with acute myocardial infarction.
Shintani, S, Murohara, T, Ikeda, H, Ueno, T, Honma, T, Katoh, A, Sasaki, K, Shimada, T, Oike, Y, Imaizumi, T
Circulation. 2001;(23):2776-9
Abstract
BACKGROUND Endothelial progenitor cells (EPCs) circulate in adult peripheral blood (PB) and contribute to neovascularization. However, little is known regarding whether EPCs and their putative precursor, CD34-positive mononuclear cells (MNC(CD34+)), are mobilized into PB in acute ischemic events in humans. METHODS AND RESULTS Flow cytometry revealed that circulating MNC(CD34+) counts significantly increased in patients with acute myocardial infarction (n=16), peaking on day 7 after onset, whereas they were unchanged in control subjects (n=8) who had no evidence of cardiac ischemia. During culture, PB-MNCs formed multiple cell clusters, and EPC-like attaching cells with endothelial cell lineage markers (CD31, vascular endothelial cadherin, and kinase insert domain receptor) sprouted from clusters. In patients with acute myocardial infarction, more cell clusters and EPCs developed from cultured PB-MNCs obtained on day 7 than those on day 1. Plasma levels of vascular endothelial growth factor significantly increased, peaking on day 7, and they positively correlated with circulating MNC(CD34+) counts (r=0.35, P=0.01). CONCLUSIONS This is the first clinical demonstration showing that lineage-committed EPCs and MNC(CD34+), their putative precursors, are mobilized during an acute ischemic event in humans.