Abstract: The eye lens is mainly composed of the highly ordered water-soluble (WS) proteins named crystallins. The aggregation and insolubilization of these proteins lead to progressive lens opacification until cataract onset. Although this is a well-known disease, the mechanism of eye lens protein aggregation is not well understood; however, one of the recognized causes of proteins modification is related to the exposure to UV light. For this reason, the spectroscopic properties of WS lens proteins and their stability to UV irradiation have been evaluated by different biophysical methods including synchrotron radiation circular dichroism, fluorescence, and circular dichroism spectroscopies. Moreover, dynamic light scattering, gel electrophoresis, transmission electron microscopy, and protein digestion followed by tandem LC–MS/MS analysis were used to study the morphological and structural changes in protein aggregates induced by exposure to UV light. Our results clearly indicated that the exposure to UV radiation modified the protein conformation, inducing a loss of ordered structure and aggregation. Furthermore, we confirmed that these changes were attributable to the generation of reactive oxygen species due to the irradiation of the protein sample. This approach, involving the photodenaturation of proteins, provides a benchmark in high-throughput screening of small molecules suitable to prevent protein denaturation and aggregation.

Background: In most European eye banks, human donor corneas are microbiologically tested after storage in organ culture conditions, and the tissues that are free of contamination are distributed for transplantation. In this prospective study, 100 donor corneas were tested for microbial contamination after cold storage, corneal culture and corneal deswelling at the Eye Bank of Rome.

Methods: Samples of cold storage medium (EUSOL‐C), corneal culture medium (TISSUE‐C) and deswelling medium (CARRY‐C) were tested after three, seven and one days of corneal storage, respectively. The CARRY‐C medium, used to transport the cornea to the operation theatre, was retested one day after transplantation. The TISSUE‐C and CARRY‐C media were also tested after removing antimicrobial and antifungal agents using a dedicated device.

Results: We found 67% of the EUSOL‐C samples were contaminated mainly by Staphylococcus spp., 14% of TISSUE‐C media were contaminated by bacteria and fungi and 3% of CARRY‐C media by Staphylococcus spp. The analysis performed after removing the antimicrobial and antifungal agents showed growth in three additional TISSUE‐C samples (S. viridans, S. haemolyticus and E. faecalis) and one CARRY‐C (S. cerevisiae and P. acnes).

Conclusion: Tissue contamination was unexpectedly high on arrival to the eye bank, indicating the need to review and update decontamination procedures during tissue recovery, and renew training for the recovery teams. Storing donor corneas in organ culture conditions significantly reduced the microorganism burden. Using devices to remove antimicrobial and antifungal agents from samples before testing can increase the sensitivity of the standard microbiological method, and thus help further reduce the risk of microbial transmission.