trans-4-(Aminomethyl)cyclohexane carboxylic acid methylamide (t-AMCHA methylamide) inhibits the physical interaction between urokinase-type plasminogen activator and stratum corneum, and accelerates the recovery of barrier function

Potential Role of Tranexamic Acid in Rosacea Treatment: conquering Flushing Beyond Melasma

Rosacea is a chronic inflammatory skin disease that affects a patient's appearance and quality of life. It mainly affects the midface region and presents as erythema, flushing, telangiectasia, papules, pustules, and rhinophyma. Despite its prevalence, the precise pathophysiology of rosacea remains unknown, and novel pharmacological therapies are currently under investigation. Tranexamic acid (TA) is a synthetic, lysine-like compound that competitively inhibits fibrinogen production by synthesizing fibrinolytic enzymes. In addition to its popular application in hemorrhage treatment, TA has been used to manage a number of skin conditions, including melasma, chronic urticaria, and angioedema. TA is a better option for melasma treatment. However, the role of TA in treating rosacea has not yet been systematically elucidated. In this study, we reviewed all available literature on the use of TA for rosacea treatment. The included articles examined the therapeutic effects of TA in patients with rosacea, including traditional methods such as oral and topical administration and more novel approaches such as intradermal injections, microneedling, and laser-assisted delivery. Several recent clinical studies demonstrated that TA alleviates rosacea symptoms by restoring the permeability barrier, ameliorating the immune reaction, and inhibiting angiogenesis. In this review, we summarized the function and potential application of TA in rosacea treatment, aiming to facilitate the implementation of clinical applications.

Exploring the Pathogenesis and Mechanism-Targeted Treatments of Rosacea: Previous Understanding and Updates

Rosacea is a chronic inflammatory skin disease characterized by recurrent erythema, flushing, telangiectasia, papules, pustules, and phymatous changes in the central area of the face. Patients with this condition often experience a significant negative impact on their quality of life, self-esteem, and overall well-being. Despite its prevalence, the pathogenesis of rosacea is not yet fully understood. Recent research advances are reshaping our understanding of the underlying mechanisms of rosacea, and treatment options based on the pathophysiological perspective hold promise to improve patient outcomes and reduce incidence. In this comprehensive review, we investigate the pathogenesis of rosacea in depth, with a focus on emerging and novel mechanisms, and provide an up-to-date overview of therapeutic strategies that target the diverse pathogenic mechanisms of rosacea. Lastly, we discuss potential future research directions aimed at enhancing our understanding of the condition and developing effective treatments.

Intradermal tranexamic acid microinjections: a novel treatment option for erythematotelangiectatic rosacea

BACKGROUND

Treatment options for erythematotelangiectatic rosacea (ETR) are still scarce. Tranexamic acid (TXA) is an antifibrinolytic drug that was recently used for the treatment of ETR.

AIMS

To evaluate the efficacy and safety of intradermal microinjections of TXA for ETR.

PATIENTS/METHODS

This was a retrospective study enrolling patients, treated with TXA intradermal microinjections for ETR, from January 2019 to February 2020. Response to treatment was assessed based on subjective symptoms, clinical photographs, and the Investigator Global Assessment of Rosacea Severity Score (IGA-RSS).

RESULTS

Six patients were included. The mean number of monthly intradermal TXA microinjections was 5.1 ± 1.3. The mean decrease of IGA-RSS was 2.4 ± 0.5. Local side effects, mainly transient erythema and swelling, were noticed in three cases. No systemic effects were noted. Clinical improvement, in respondent patients, lasted after 3 months of follow-up.

CONCLUSION

Intradermal TXA microinjections are a safe and effective treatment option for ETR. The optimal number of monthly sessions has yet to be determined.

The influence of topical 5% tranexamic acid at pH 2.38 with and without corundum microdermabrasion on pigmentation and skin surface lipids

Tranexamic acid (TA) has anti-hemorrhagic effects; however, oral administration has been found to decrease hyperpigmentation. The aim of the work was to compare the effects of treatment with 5% tranexamic acid in combination with corundum microdermabrasion on skin pigmentation, redness, pH, transepidermal water loss (TEWL), sebum level and hydration of back surface and dorsal surface of the hand skin. Six treatments were performed every week on the back surface and both dorsal surfaces of the hands of 12 subjects. The entire back/both hands were treated with 5% tranexamic acid at pH 2.38; left side of the back or left hand were also subjected to corundum microdermabrasion. Skin parameters were measured using the Courage & Khazaka 580 Multi Probe Adapter. Clinical photos were taken using the Fotomedicus system. Significant differences between treatment methods were observed for melanin, erythema and pH. In addition, the two methods differed significantly with regard to the amount of sebum, TEWL and the level of moisture in the skin. Both methods gave similar acidic pH. Summing up tranexamic acid causes a significant reduction in epidermal melanogenesis, has a significant impact on the level of skin hydration, lipids of the epidermis and maintaining the proper TEWL. TA has a significant effect on reducing skin redness.

Tranexamic acid blocks the thrombin-mediated delay of epidermal permeability barrier recovery induced by the cedar pollen allergen, Cry j1

We previously demonstrated that Cry j1, the major pollen allergen of Cryptomeria japonica (Japanese cedar), transiently increases protease activity and intracellular Ca²⁺ concentration in cultured human keratinocytes, and delays recovery after stratum corneum barrier disruption in human skin ex vivo. Topical application of tranexamic acid or trypsin-type serine protease inhibitors accelerates barrier recovery. We hypothesized that tranexamic acid might prevent the transient protease activity increase and the barrier recovery delay induced by Cry j1. Here, we tested this hypothesis and examined the mechanism involved. In cultured human keratinocytes, knock-down of protease-activated receptor 1 (PAR-1) reduced the transient increase of calcium induced by Cry j1, whereas knock-down of PAR-2 did not. Knock-down of thrombin significantly reduced the transient increases of calcium concentration and protease activity. Tranexamic acid, soybean trypsin inhibitor, or bivalirudin (a thrombin inhibitor) also reduced the calcium elevation induced by Cry j1 and/or thrombin. Co-application of tranexamic acid or bivalirudin with Cry j1 to human skin ex vivo blocked the delay of barrier recovery. These results suggest that thrombin and PAR-1 or PAR-1-like receptor might mediate the adverse effects of Cry j1 on human epidermal keratinocytes, and could open up a new strategy for treating inflammatory skin diseases.

The effects of benzylsulfonyl-D-Ser-homoPhe-(4-amidino-benzylamide), a dual plasmin and urokinase inhibitor, on facial skin barrier function in subjects with sensitive skin

OBJECTIVE

The aim of this study was to optimize the synthesis of the plasmin and urokinase (uPA) inhibitor benzylsulfonyl-D-Ser-homoPhe-(4-amidino-benzylamide) (BSFAB), to characterize its activity and mechanism of action and to assess its use to improve stratum corneum (SC) barrier function.

METHODS

Peptide coupling methods were used to synthesize BSFAB, and high-performance liquid chromatography-mass spectrometry (HPLC-MS) together with ¹ H- and ¹³ C-nuclear magnetic resonance spectroscopy (NMR) were applied to clarify its structure and determine its purity. Its binding mode was determined by docking studies to the catalytic domains of plasmin and uPA. Inhibition constants (K_i ) were determined by enzyme kinetic studies, and the effect of BSFAB on plasmin, uPA and transglutaminase 1 expression was evaluated in non-cytokine and cytokine-stimulated keratinocytes. A vehicle-controlled clinical study on SC barrier function was conducted on facial skin of subjects with self-perceived sensitive skin.

RESULTS

BSFAB was synthesized with high purity (97.3%). In silico studies indicated that the amidine moiety of BSFAB was anchored in the S1 pocket of both enzymes by binding to Asp189, Ser190 and Gly219, whereas the backbone of the D-Ser residue makes an anti-parallel β-sheet interaction with Gly216. BSFAB was shown to be an effective inhibitor of plasmin and uPA with K_i values of 29 and 25 nM, respectively. BSFAB also inhibited keratinocyte-secreted protease activities in basal (plasmin inhibition 37.7%, P < 0.05 and uPA inhibition 96.6%, P < 0.01) and cytokine-induced conditions (plasmin inhibition 41.1%, P < 0.05 and uPA inhibition 97.0%, P < 0.001) and stimulated the gene expression of transglutaminase 1 in cytokine-stimulated keratinocytes (approximately 4.5 times increased expression, P < 0.01). Clinically, BSFAB was shown to improve SC barrier integrity (P < 0.02 on day 29) and subjective improvements in the perception of healthy skin (P < 0.05 on day 28).

CONCLUSION

BSFAB binds as a reversible competitive inhibitor to the active sites of plasmin and uPA. Additionally, BSFAB positively improved keratinocyte differentiation gene expression (transglutaminase 1). These effects were translated into improvements in SC barrier integrity clinically in subjects with dry and sensitive skin and improved their perception of having a healthy skin condition.