Brimonidine is a highly selective α2-adrenergic receptor agonist approved by the FDA for the treatment of rosacea. Rosacea is a major clinical disease with vasodilatation and rash on the centre of the face, and that brimonidine as a vasoconstrictor can act as a remedy for rosacea. However, there is no study of how brimonidine has an effect on rosacea-related immune cells or mechanisms in the skin to improve rosacea. In this study, we observed that clinical features of rosacea induced by LL-37 in Balb/c mice were improved after the application of brimonidine gel, and we also showed a marked decrease in the number of inflammatory cells, especially mast cells (MCs) histologically. Furthermore, we confirmed that mRnA levels of MC enzymes increased by LL-37 were reduced by brimonidine gel. To our knowledge, we first found that brimonidine has a mechanism of treating rosacea by reducing the number and mRnA levels of MC-specific enzymes, an important immune cell in the pathogenesis of rosacea. | BACKGROUNDRosacea is a common chronic inflammatory skin disease characterized by telangiectasia and flushing.[1] The erythema of rosacea is thought to result from abnormal cutaneous vasomotor activity in the central part of the face. Brimonidine tartrate 0.33% gel (Mirvaso gel; Galderma, Lausanne, Switzerland), a highly selective α2-adrenergic receptor agonist, was recently recommended for the treatment of persistent facial erythema in patients with rosacea due to its potent vasoconstrictive effects. [2] Several clinical studies have demonstrated that brimonidine rapidly improves facial flushing and erythema. [2,3] However, the molecular and histological effects of brimonidine on rosacea remain largely unknown. Although the vasoconstrictive property of brimonidine gel has been suggested to contribute to the therapeutic effect, it was assumed that not only contracting the expanded blood vessels would act on the therapeutic mechanism. | QUESTION ADDRESSEDThe aims of this study were to investigate the histological changes and gene expression levels in rosacea-like skin lesions when applied with brimonidine and to identify the role of brimonidine gel in the pathogenesis of rosacea. In this study, we investigated whether brimonidine gel could influence the number of mast cells (MCs) and mRnA levels of tryptase and chymase by evaluating the response of topical application of brimonidine gel to rosacea-like skin lesions in mice. | EXPERIMENTAL DESIGNThirty-five 7-week-old female Balb/c mice were used in this study (Dooyeol Biotech, Seoul, Korea). The experimental protocol was approved by the Animal Care Committee of Catholic University of Korea. The mice were divided into three groups: control (n=11), LL-37 (n=12), and LL-37 plus brimonidine (LL-37+ brimonidine; n=12). The mice in the LL-37 and LL-37+ brimonidine groups had LL-37 injected intradermally into shaved back skin to induce rosacea-like skin lesions.Immediately after the injection of LL-37 (40 μL), the mice in the LL-37+ brimonidine group had brimonidine tartrate 0.3...
There is evidence that telomere length (TL), telomerase activity (TA), and age are related to the replicative potential of human nucleus pulposus chondrocytes (NPCs). However, it has not yet been established if any of these factors can serve as predictors of the replicative potential of NPCs. To establish predictors of the replicative potential of NPCs, we evaluated potential relationships between replicative capacity of NPCs, initial TL (telomere length at the first passage), initial TA (telomerase activity at the first passage), and age. Nucleus pulposus specimens were obtained from 14 patients of various ages undergoing discectomy. NPCs were serially cultivated until the end of their replicative lifespans. Relationships among cumulative population doubling level (PDL), initial TL, initial TA, and age were analyzed. Initial TA was negatively correlated with age (r = -0.674, P = 0.008). However, no correlation between initial TL and age was observed. Cumulative PDL was also negatively correlated with age (r = -0.585, P = 0.028). Although the cumulative PDL appeared to increase with initial TL or initial TA, this trend was not statistically significant. In conclusion, age is the sole predictor of the replicative potential of human NPCs, and replicative potential decreases with age. Initial TL and initial TA are not predictors of replicative potential, and can serve only as reference values.
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