Tear Neuromediators in Subjects with and without Dry Eye According to Ocular Sensitivity / 전남의대학술지

To investigate differences of tear neuromediators between subjects with and without dry eye (DE) depending on the ocular sensitivity. Thirty-one subjects with DE and 29 subjects without DE were recruited in this study. The eyes were stimulated by exposure to an irritating product applied to the periocular region. Both DE and non-DE subjects were divided into the high sensitivity and low sensitivity groups based on the degree of ocular sensitivity to ocular irritation. Baseline tear film break-up time (TBUT) and corneal staining score were examined, and tear samples were collected. The concentrations of the tear neuromediators, including nerve growth factor (NGF), serotonin, calcitonin gene-related peptide (CGRP), substance P, neuropeptide Y, and vasoactive intestinal peptide were measured using the enzyme-linked immune sorbent assay. The baseline neuromediator concentrations were compared between subjects with and without DE based on ocular sensitivity. In both DE and non-DE subjects, baseline TBUT was significantly lower in the high sensitivity group than in the low sensitivity group. In the high sensitivity group, baseline tear NGF levels were higher in subjects with DE than in those without DE. In the low sensitivity group, baseline levels of tear CGRP were lower in subjects with DE than in those without DE. Tear neuromediators associated with DE had differences in their concentrations depending on ocular sensitivity. In patients with DE, tear NGF levels increased with high ocular sensitivity to ocular irritation, whereas tear CGRP levels decreased with low ocular sensitivity.

Antifungal Mechanism of Action of Lauryl Betaine Against Skin-Associated Fungus Malassezia restricta

Betaine derivatives are considered major ingredients of shampoos and are commonly used as antistatic and viscosity-increasing agents. Several studies have also suggested that betaine derivatives can be used as antimicrobial agents. However, the antifungal activity and mechanism of action of betaine derivatives have not yet been fully understood. In this study, we investigated the antifungal activity of six betaine derivatives against Malassezia restricta, which is the most frequently isolated fungus from the human skin and is implicated in the development of dandruff. We found that, among the six betaine derivatives, lauryl betaine showed the most potent antifungal activity. The mechanism of action of lauryl betaine was studied mainly using another phylogenetically close model fungal organism, Cryptococcus neoformans, because of a lack of available genetic manipulation and functional genomics tools for M. restricta. Our genome-wide reverse genetic screening method using the C. neoformans gene deletion mutant library showed that the mutants with mutations in genes for cell membrane synthesis and integrity, particularly ergosterol synthesis, are highly sensitive to lauryl betaine. Furthermore, transcriptome changes in both C. neoformans and M. restricta cells grown in the presence of lauryl betaine were analyzed and the results indicated that the compound mainly affected cell membrane synthesis, particularly ergosterol synthesis. Overall, our data demonstrated that lauryl betaine influences ergosterol synthesis in C. neoformans and that the compound exerts a similar mechanism of action on M. restricta.