Riboflavin and UV-Light Based Pathogen Reduction: Extent and Consequence of DNA Damage at the Molecular Level

Abstract

We are developing a technology based on the combined application of riboflavin (RB) and light for inactivating pathogens in blood products while retaining the biological functions of the treated cells and proteins. Virus and bacteria reduction measured by tissue culture infectivity or colony formation with UV light alone and in combination with RB yield equivalent results. The effects of RB as a sensitizing agent on DNA in white cells, bacteria and viruses in combination with UV light exposure have been evaluated. UV-mediated DNA degradation in Jurkat T cells and leukocytes in plasma as measured by the FlowTACS assay was significantly increased in the presence of RB. Agarose gel electrophoretic analysis of DNA in Escherichia coli and leukocytes in plasma demonstrated enhanced DNA degradation in the presence of RB. UV light in combination with RB prevented the reactivation of lambda phage compared with samples irradiated in the absence of RB. UV-mediated oxidative damage in calf thymus DNA was also enhanced in the presence of RB. These observations clearly demonstrate that the presence of RB and UV light selectively enhances damage to the guanine bases in DNA. These data also suggest that the type and extent of damage to DNA for virus in the presence of RB and light make it less likely to be repaired by normal repair pathways available in host cells.

Combined treatment with flap amputation, phototherapeutic keratectomy, and collagen crosslinking in severe intractable post-LASIK atypical mycobacterial infection with corneal melt

“…1,2 The combination of riboflavin and UVA light (365 m) has been used to purify blood products in transfusion medicine. [13][14][15] In vitro studies by Martins et al 5 demonstrated the antimicrobial properties of riboflavin-UVA against common pathogens causing keratitis. A few clinical reports demonstrate the use of CXL in unresponsive keratitis.…”

Corneal Cross-linking as an Adjuvant Therapy in the Management of Recalcitrant Deep Stromal Fungal Keratitis: A Randomized Trial

“…[15][16][17][18] However, CXL may also have detrimental effects for infectious keratitis, since animal studies have shown that CXL reduces the permeability of the cornea to antimicrobial medications. 19 It is unclear why CXL was not effective in the present study, but it is possible that this technique could have variable efficacy depending on the organism, severity of the ulcer (eg, infiltrate depth, infiltrate diameter, stromal thinning, limbal involvement), host response, or other poorly understood factors.…”

Evaluation of antibacterial efficacy of photo-activated riboflavin using ultraviolet light (UVA)

“…Extensive investigation of this phenomenon indicates that microbes are damaged by non-specific oxidative stress, mediated by reactive oxygen species as well as by intercalation of the riboflavin molecule into the RNA and DNA of micro-organisms [2][3][4]. A wide range of microorganisms including viruses, bacteria, and parasites have been effectively inactivated by the photosensitization of riboflavin using UV light.…”