Genipin in an Ex Vivo Corneal Model of Bacterial and Fungal Keratitis

Abstract

Purpose To determine whether genipin (a natural crosslinker) could reduce the colonization and proliferation of bacteria and fungi in an ex vivo model of corneal infection. Methods This study, using an ex vivo model of bacterial and fungal keratitis, investigated the antimicrobial efficacy of genipin crosslinking. Excised corneoscleral buttons were wounded by scalpel incision and subsequently infected with Staphylococcus aureus , Pseudomonas aeruginosa , or Candida albicans . After inoculation, corneas were treated with genipin for 24 hours at 37°C. Histologic examinations were carried out, and the number of viable colony-forming units (CFU)/cornea was determined. Results Genipin exerts bactericidal action against S. aureus and P. aeruginosa , as well as fungicidal action against C. albicans and significantly reduced the CFU compared to contralateral eyes that received saline treatment ( P < 0.05). Conclusions These data identify genipin as a novel ocular antimicrobial agent that has the potential to be incorporated into the therapeutic armamentarium against microbial keratitis. Translational Relevance This study provided evidence for the antimicrobial and antifungal properties of genipin as an alternative crosslinker that could be used in the management of infectious keratitis.

A Pilot Study to Evaluate Genipin in Staphylococcus aureus and Pseudomonas aeruginosa Keratitis Models: Modulation of Pro-Inflammatory Cytokines and Matrix Metalloproteinases

“…Our previous studies showed that genipin, a natural crosslinking agent, has antibacterial properties and reduces the colonization and proliferation of S. aureus and P. aeruginosa in an ex vivo corneal infection model [ 46 ]. We also recently demonstrated that genipin is associated with minimal corneal toxicity, effective crosslinking activities, and, importantly, that it increases corneal stromal resistance to enzymatic digestion [ 45 , 67 ].…”

“…“Genipin is a naturally occurring iridoid compound extracted from the Gardenia jasminoides Ellis plant” [ 44 ]. Genipin has been reported to have various pharmacological actions, such as antimicrobial [ 45 , 46 ], anticancer [ 47 , 48 , 49 ], anti-inflammatory [ 50 , 51 ], hepatoprotective [ 48 ], and neurotrophic effects [ 52 ]. Its great potential as a natural crosslinking agent for biomaterials was first noted when genipin was compared to glutaraldehyde and demonstrated comparable crosslinking ability but significantly lower toxicity [ 53 , 54 , 55 ].…”

“…Previously, we demonstrated the effects of corneal genipin crosslinking in ex vivo and in vivo models with minimal toxicity [ 45 , 58 , 59 ]. Several studies on sclera have also shown successful stiffening and biocompatibility in different animal models [ 55 , 60 , 61 , 62 , 63 , 64 ], supporting the prospect of sclera genipin crosslinking for the treatment of glaucoma and myopia.…”

“…Several studies on sclera have also shown successful stiffening and biocompatibility in different animal models [ 55 , 60 , 61 , 62 , 63 , 64 ], supporting the prospect of sclera genipin crosslinking for the treatment of glaucoma and myopia. In addition, genipin has anti-inflammatory [ 44 , 50 , 63 , 65 ], antioxidant [ 52 , 66 ], and antibacterial/ antifungal properties [ 45 , 46 ]. Genipin has also been shown to delay corneal stromal melting and increase tissue resistance to enzymatic digestion [ 67 ].…”

Therapy for contact lens-related ulcers

“…Rose Bengal photodynamic antimicrobial therapy has also shown promising results in vitro and in vivo against bacteria and fungus [ [88][89][90][91] and in vivo against Fusarium and Acanthamoeba [92,93]. Other cross-linking agents being investigated include genipin [94], TONS504 (cationic chlorin derivative photosensitizer) [95], IQ-Cm [a type of aggregationinduced emission luminogens (AIEgens)] [96], and a modified Photosensitizer-based boron dipyrromethene (BODIPY) chromophore [97].…”