1Universitätsklinikum des Saarlandes Innere Medizin III - Kardiologie, Angiologie und internistische Intensivmedizin Homburg/Saar, Deutschland; 2Universitätsklinikum des Saarlandes Dermatologie, Venerologie, Allergologie Homburg, Deutschland; 3Universität des Saarlandes Zellbiologie und Anatomie Homburg, Deutschland; 4Universität des Saarlandes Klinische und experimentelle Toxikologie Homburg, Deutschland
Introduction: Cardiovascular drugs, especially hydrochlorothiazide (HCT), have been suspected to be phototoxic thereby increasing the risk of skin cancer in susceptible individuals. These suspicions, however, are based on non-human preclinical data and retrospective observational evidence. This study aimed to assess the photosensitizing and phototoxic properties of cardiovascular drugs in human cadaveric skin.
Methods: Human cadaveric skin was taken by biopsy <24 hours after death of body donors. Skin samples were cultured in Dulbecco’s modified eagles’ medium with streptomycin and penicillin. Skin samples were incubated with 1mMol HCT (for 24 hours) and irradiated with three bursts of 100 mJ ultraviolet radiation type B (UVB). 24 hours after irradiation, western blots and real time polymerase chain reaction were performed to assess mediators of fibrosis (CTGF,), inflammation (TNFa) and oncoproteins (p53). Respective controls were either entirely untreated or treated with either HCT or UVB. For statistical analysis multiple comparisons using Turkey´s multiple comparisons test was performed.
Results: Human cadaveric skin was vital up to 7 days after death and expressed proinflammatory and profibrotic mediators after 3 x 100 mJ UVB irradiation (mean difference in gene expression for TNFa after 24h compared to control 1.32; 95% CI: 0.06-2.59, p=0.04, n=1). The combination of radiation and HCT did not increase expression of inflammatory marker genes (mean difference in gene expression for TNFa in skin treated with HCT and irradiated with 3 x 100 mJ UVB as compared to skin that has only been irradiated with 3 x 100 mJ 0.60; 95% CI: -0.66-1.87, p=0.59), or oncoproteins 24 hours after irradiation (mean difference in gene expression for p53 in skin treated with HCT and irradiated with 3 x 100 mJ UVB as compared to skin that has only been irradiated with 3 x 100 mJ 0.23; 95% CI: -0.14-0.59, p=0.37). HCT therapy did increase the expression of profibrotic genes after 24 hours (mean difference in gene expression for CTGF in skin treated with HCT and irradiated with 3 x 100 mJ UVB as compared to skin that has only been irradiated with 3 x 100 mJ 3.14; 95% CI: 0.61-5.60, p<0.01).
Conclusion: Human cadaveric skin appears to be a suitable model for testing phototoxic effects of cardiovascular substances. Except for an increase in CTGF, no phototoxic effects of HCT were detected in combination with UVB irradiation. The evidence surrounding the suspicions of HCT to be photosensitizing or phototoxic remains contradictory.
Central Illustration: A.) Relative gene expression as normalized to glycerinaldehyde-3-phosphat-dehydrogenase of tumor protein 53 (TP53) in skin not treated (control), skin irradiated with three bursts of 100 mJ UVB, skin only treated with hydrochlorothiazide (HCT) and skin treated with HCT and irradiated with three bursts of 100 mJ UVB. B.) Relative gene expression as normalized to GAPDH of connective tissue growth factor (CTGF) in skin not treated (control), skin irradiated with three bursts of 100 mJ UVB, skin only treated with hydrochlorothiazide (HCT) and skin treated with HCT and irradiated with three bursts of 100 mJ UVB.