Purpose.: Previously, aliphatic β-nitroalcohols (BNAs) have been studied as a means to chemically induce tissue cross-linking (TXL) of cornea and sclera. There are a number of related and possibly more potent agents, known as formaldehyde releasers (FARs), that are in commercial use as preservatives in cosmetics and other personal care products. The present study was undertaken in order to screen such compounds for potential clinical utility as therapeutic TXL agents. Methods.: A chemical registry of 62 FARs was created from a literature review and included characteristics relevant to TXL such as molecular weight, carcinogenicity/mutagenicity, toxicity, hydrophobicity, and commercial availability. From this registry, five compounds [diazolidinyl urea (DAU), imidazolidinyl urea (IMU), sodium hydroxymethylglycinate (SMG), DMDM hydantoin (DMDM), 5-Ethyl-3,7-dioxa-1-azabicyclo [3.3.0] octane (OCT)] were selected for efficacy screening using two independent systems, an ex vivo rabbit corneal cross-linking simulation setup and incubation of cut scleral tissue pieces. Treatments were conducted at pH 7.4 or 8.5 for 30 minutes. Efficacy was evaluated using thermal denaturation temperature (T_m), and cell toxicity was studied using the trypan blue exclusion method. Results.: Cross-linking effects in the five selected FARs were pH and concentration dependent. Overall, the T_m shifts were in agreement with both cornea and sclera. By comparison with BNAs previously reported upon, the FARs identified in this study were significantly more potent but with similar or better cytotoxicity. Conclusions.: The FARs, a class of compounds well known to the cosmetic industry, may have utility as therapeutic TXL agents. The compounds studied thus far show promise and will be further tested.

Samphire (Crithmum matrimum), a halophyte, thrives in saline environments due to its salt tolerance, which is partly attributed to miR167. However, the functional role of miR167 in human cells is unclear. This study explores the role of extracellular vesicles (EVs) derived from C. matrimum callus in skin regeneration, highlighting the potential of miRNA tae-miR167c-5p (miR167). Calluses were successfully induced and scaled for EV isolation. Characterization confirmed the presence of plant EV biomarkers and EVs with an average size of 136.6 nm. Cm-callus EVs enhanced wound healing and skin regeneration in human fibroblasts (HFF cells and CCD-986Sk cells) by modulating key genes, in particular, by downregulating MMP1 and upregulating COL1A1 and VEGFA. Small RNA sequencing revealed an enrichment of miR167 in Cm-callus EVs. Transfection with an miR167 mimic replicated these regenerative effects. Computational predictions identified PPP3R2, which is linked to the MAPK and NFAT pathways, as a potential target of miR167. This study demonstrates the efficacy of Cm-callus EVs and miR167 in promoting skin regeneration without cytotoxicity, providing insights into their therapeutic potential and calling for further experimental validation of target interactions.

Wound healing is a complex and dynamic process involving several stages of tissue repair. This study has shown that extracellular vesicles (EVs) derived from the callus of Camellia japonica L. and their associated microRNAs (miRNAs) possess significant wound healing activities. In human fibroblasts, EVs from C. japonica L. stimulated wound healing and upregulated collagen gene expression. The EVs also decreased inflammation levels in human keratinocytes, supporting wound healing. Among the miRNAs identified, miR408, one of the abundant miRNAs in the EVs, also showed similar wound healing efficacy. These findings suggest that both EVs and miR408 from the callus of C. japonica L. play a pivotal role in promoting wound healing. Additionally, this study shows that the regulation of miRNAs between different kingdoms can be achieved and suggests a new direction for the utilization of plant-derived components.