gms | German Medical Science

Background and purpose: Persisting epithelial defects are major complications of effective acanthamoeba keratitis therapy. The purpose of this study was to analyze the effects of different concentrations of diamidines (hexamidine diisethionat (HD), propamidin isethionate (PD), dibromopropamidine diisethionat (DD)) and biguanides (polyhexamethylen biguanid (PHMB), chlorhexidine (CH)) on human corneal epithelial cells, keratocytes and endothelial cells, in vitro.

Methods: For epithelial (HCEC) and endothelial cells (HCEC-12) a human cell line and for keratocytes primary cultures were used (n=6 each). We used 3.9x10-4-0.1% HD, PD or DD, 3.9x10-4-0.0125% PD and 7.8x10-5-0.02% PHMB or CH concentrations for 24 hours for our experiments. Cell cultures without diamidine or biguanide were used as controls. Viability was analyzed using Cell Proliferation Kit XTT.

Results: Epithelial cell viability decreased significantly from 7.8x10-4% DD, 1.6x10-3% HD and 3.1x10-3% PD and from 3.1x10-4% PHMB and CH concentrations (P≤0.038), keratocyte viability decreased significantly from 7.8x10-4% DD and HD, 3.1x10-3% PD, 3.1x10-4% PHMB and 6.3x10-4% CH concentrations (P≤0.038), endothelial cell viability decreased significantly from 1.6x10-3% HD, 3.1x10-3% DD, 6.3x10-3% PD, 6.3x10-4% PHMB or CH concentrations (P≤0.038), compared to controls. At 6.3x10-3% concentration, epithelial cell viability was significantly less using DD or HD than using the same PD concentration (P=0.026; P=0.011). It was significantly worse using 6.3 x10-4% or 1.3 x10-3% PHMB than using the same CH concentration (P=0.011; P=0.007). Keratocyte / endothelial cell viability was significantly worse using 3.1x10-3% HD, than using the same concentration of DD or PD (P=0.004/P=0.017; P=0.001/P=0.0006). Keratocyte viability was significantly less using 3.1x10-4% or 6.3x10-4% CH than using the same concentration of PHMB (P=0.017; P=0.0006).

Conclusion: PD decreases human cell viability less than DD and HD, whereas CH decreases viability less than PHMB. Our result suggest, that propamidin isethionate as diamidine and chlorhexidin as biguanide should be used in order to reduce cytotoxicity of antiacanthemoeba treatment on human epithelial cells, keratocytes and endothelial cells.