[Effects of ionizing radiation on the blood vessel wall].
OBJECTIVE
To study the biologic and clinical effects of ionizing radiation on blood vessels.


METHODS
Data extracted from experimental and clinical reports and articles.


RESULTS
Radiation-induced demise of endothelial cells is due to apoptosis. These cells are considered to be very radiosensitive. In vivo, however, the basal membrane might play a protective role. Early effects are characterized by swelling and shloughing of endothelial cells. Late effects are due to endothelial and smooth muscular cell proliferation. The underlying biologic mechanisms are little known. One hypothesis is the production of PDGF (platelet-derived growth factor) and FGF (fibroblast growth factor) by endothelial cells. Perivascular fibrosis might occur because of the TGF-beta production by endothelial cells and/or macrophages. Occurrence of late complications is probably multifactorial. Individual susceptibility to harmful effects of ionizing radiation, other vascular risk factors, and non optimal use of radiation treatment might contribute to the occurrence of late vascular complications. Modern radiotherapy using new techniques as the intensity modulation radiation therapy (IMRT) and the reduction of radiation doses and size of radiation fields should permit a dramatic reduction of vascular complications in cancer patients.


CONCLUSIONS
Ionizing radiation treatments can lead to serious late vascular complications. A better understanding of the underlying biologic processes and newer radiation techniques might lead to fewer late complications in the very near future.
Girinsky
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Département des radiations, Institut Gustave Roussy, 94805 Villejuif.
D000818:Animals; D016923:Cell Death / Q000528:radiation effects; D004730:Endothelium, Vascular / Q000293:injuries / Q000378:metabolism / Q000528:radiation effects*; D005346:Fibroblast Growth Factors / Q000096:biosynthesis; D005355:Fibrosis; D006801:Humans; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis; D011832:Radiation Injuries / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D011833:Radiation Injuries, Experimental / Q000209:etiology / Q000473:pathology; D011836:Radiation Tolerance; D011839:Radiation, Ionizing; D011878:Radiotherapy / Q000009:adverse effects; D013997:Time Factors; D014657:Vasculitis / Q000209:etiology / Q000473:pathology / Q000517:prevention & control
D010982:Platelet-Derived Growth Factor; D005346:Fibroblast Growth Factors