Radiation-Induced Vascular Injury and Its Relation to Late Effects in Normal Tissues

The rationale behind autologous autoimmune hematopoietic stem cell transplant conditioning regimens: concerns over the use of total-body irradiation in systemic sclerosis

“…The severity of vascular damage induced by radiation appears to depend on species, organ, dose, and patient susceptibility. 38 Small vessels such as capillaries are more susceptible to lower doses of radiation-induced late injury compared to larger vessels. 38 Radiation at even very low-dose chronic exposure is associated with damage to the microcirculation.…”

“…38 Small vessels such as capillaries are more susceptible to lower doses of radiation-induced late injury compared to larger vessels. 38 Radiation at even very low-dose chronic exposure is associated with damage to the microcirculation. 38 Fingernail-bed capillary microscopy of 145 physicians such as radiation oncologists and interventional radiologists with exposure to ionizing radiation at levels under 5 rem/year was compared to 106 control subjects comparable in age, sex, smoking history, blood glucose, and family history of diabetes but not exposed to low-level work place radiation.…”

“…38 Radiation at even very low-dose chronic exposure is associated with damage to the microcirculation. 38 Fingernail-bed capillary microscopy of 145 physicians such as radiation oncologists and interventional radiologists with exposure to ionizing radiation at levels under 5 rem/year was compared to 106 control subjects comparable in age, sex, smoking history, blood glucose, and family history of diabetes but not exposed to low-level work place radiation. 44 The differences were statistically significant with 91% of the control group vs 19% of the radiation-exposed group showing no capillary damage.…”

“…Late radiation-induced injury which may not manifest for months or years after exposure can arise from impaired vascular function manifest by obliteration of capillaries, collagen deposition, fibrosis, and telangiectasia. 38 It is assumed that early endothelial damage and increased vascular permeability causes or initiates the late pathologic features of fibrosis, reduced blood flow, and capillary loss. For this reason, several investigators have studied the effect of radiation on vascular permeability and or blood flow in rodent models.…”

“…These are the same histologic features as seen in late radiation injury. 38 Acute radiation sickness occurs as a result of apoptosis of rapidly proliferating cells in organ systems such as skin, intestinal mucosa, and bone marrow. Late radiation-induced injury which may not manifest for months or years after exposure can arise from impaired vascular function manifest by obliteration of capillaries, collagen deposition, fibrosis, and telangiectasia.…”