In vitro analysis of radiation-induced dermal wounds.

OBJECTIVE

To investigate the pathophysiology of radiation-induced wounds of the head and neck at a molecular level.

STUDY

DESIGN

Basic science, prospective study.

SETTING

The study was conducted at the Department of Otolaryngology-Head and Neck Surgery, Ruprecht Karls-University Heidelberg, Faculty of Medicine Mannheim, Mannheim, Germany.

SUBJECTS AND

METHODS

Keratinocytes from chronic nonhealing ulcers in irradiated areas as well as from healthy skin areas in the same patients (n = 3) were harvested during surgical procedures and isolated in cell culture. First, a proliferation assay was performed. Gene expression was analyzed by microarray, protein expression by immunohistochemistry.

RESULTS

Keratinocytes from radiogenic wounds showed a shift from the high molecular keratins 1 and 10 to the low molecular keratins 5 and 14 compared to normal control skin. Keratinocytes from nonhealing wounds showed a decreased expression of transforming growth factor alpha and beta 1, fibroblast growth factor 1 and 2, keratinocyte growth factor, vascular endothelial growth factor, and hepatocyte growth factor. The matrix metalloproteinases 2, 12, and 13 showed increased expression in irradiated keratinocytes and fibroblasts.

CONCLUSION

Our data showed a change of keratinocytes to a less differentiated state due to radiation. Additionally, it seems that radiation-induced dermal injuries often fail to heal because of decreased proliferation, impaired angiogenesis, and persistently high concentrations of matrix metalloproteinases.