Therapeutic effects of iNOS inhibition against vitiligo in an animal model

Macrophage inhibitory factor alters the functionality of macrophages and their involvement in disease pathogenesis of active generalized vitiligo patients

INTRODUCTION

In autoimmune dermatitis patients, a macrophage migration inhibitory factor (MIF) is widely used to determine the severity of the diseases with other clinical parameters. Moreover, in vitiligo, MIF has shown significant positive correlation with the VASI (Vitiligo Area Scoring Index) score of both generalized and localized vitiligo patients. MIF function as pro-inflammatory cytokine and inhibited random migration of macrophages from inflammation loci. Hence, activated macrophage infiltrates promote the diseases pathogenesis. Till date, macrophages and involvement of their secreted MIF in disease severity of vitiligo patients remains undetermined.

MATERIAL AND METHOD

The frequency of both M1 and M2 macrophages was evaluated in active GV patients (n = 20) using flow cytometry in blood and in tissues by confocal microscopy (n = 10). Relative m-RNA expression and cytokine profiling of pro and anti-inflammatory mediators were estimated in PBMCs and in serum of patients. Lastly, concentration of nitric oxide and phagocytic activity from macrophages of active patients were calculated to understand the diseases pathology in detail.

RESULT

Both in circulation as well as in tissues, the infiltration of M1 macrophages was increased in active GV patients, while the percentage of M2 macrophages was comparable to healthy tissues. Aberrant expression of pro and anti-inflammatory molecules including IL-1β, IL-6, TNF-α, IL-12 and MIF impair the cellular hemostasis and induce systematic inflammation. Elevated nitric oxide and higher phagocytic activity of macrophages enhanced the destruction and/or depigmentation of melanocytes causing vitiligo.

CONCLUSION

Elevated macrophages in both tissue and blood enhanced the secretion of MIF and other inflammatory mediators that further enforce the production of nitric oxide, activation and phagocytic activity of macrophages against melanocytes and melanocytes antigens. As a result, destruction of melanocytes and melanin production occurred and caused the depigmentation and/or white macules on the skin.

Effects of Monobenzyl ether of hydroquinone on 3T3 mouse fibroblast viability and ultrastructure

Monobenzyl ether of hydroquinone (MBEH) is a topical depigmentation agent used by vitiligo patients to even the skin tone. We aimed to investigate the effects of MBEH on 3T3 mouse fibroblasts. Fibroblasts were treated with 250 µM, 500 µM, and 750 µM MBEH and vehicle (EtOH:DMSO) for 24 hours. Cell numbers of 250 µM, 500 µM, and 750 µM MBEH treated and vehicle groups decreased significantly compared to control group. TUNEL positive cell rate increased with MBEH concentration. In electron microscopic examination, control and vehicle groups showed active cells features, while mitochondrial swelling and cristae loss were seen in 250 µM MBEH-treated group. In cytoplasm of 500 µM MBEH-treated group, there were many multivesicular bodies and autophagic vacuoles. As an indication of apoptosis, cell membrane blebs and reduction in cell size were observed. In 750 μM MBEH-treated group, cells were completely degenerated. Our findings show that MBEH, which is used as a depigmentation agent to lighten the skin by destroying melanocytes, may also have dose-dependent negative effects on the viability of 3T3 mouse fibroblasts, and these may be mediated through autophagic and apoptotic cell death mechanisms.

Successful Treatment of Vitiligo with Cold Atmospheric Plasma‒Activated Hydrogel

Vitiligo shows insufficient response to current therapies largely owing to T-lymphocyte dysfunction, abnormal inflammatory activation, and excessive oxidative stress in lesions. Cold atmospheric plasma (CAP) possesses pleiotropic antioxidant and anti-inflammatory properties and may offer an improvement to current treatment options. In this study, the efficacy and safety of CAP were investigated in a mouse model of vitiligo and a randomized and controlled trial of patients with active focal vitiligo. Skin biopsies showed that topical treatment of vitiligo-like lesions on mouse dorsal skin by CAP restored the distribution of melanin. In addition, CAP treatment reduced the infiltration of CD11c+ dendritic cells, CD3+ T cells, and CD8+ T cells; inhibited the release of CXCL10 and cytokine IFN-γ; and enhanced cellular resistance to oxidative stress and excessive immune response by enhancing the expression of the transcription factor NRF2 and attenuating the activity of inducible nitric oxide synthase. In a randomized and controlled trial, CAP treatment achieved partial and complete repigmentation in 80% and 20% of vitiligo lesions, respectively, without hyperpigmentation in surrounding areas or other adverse events during the treatment period and its follow-up period. In conclusion, CAP offers a promising option for the management of vitiligo.

Anti-Inflammatory Activity of Calendula officinalis L. Flower Extract

The use of calendula for its lenitive properties’ dates to the XII century. This plant contains several bioactive compounds, including terpenoids, terpenes, carotenoids, flavonoids and polyunsaturated fatty acids. Calendula flower extract is used in soothing cosmetics, such as after-sun, sensitive skin and eye contour products. The anti-inflammatory properties of this ingredient were demonstrated in an animal model, but the mechanism of action is poorly understood. Therefore, our work explored the effect of a calendula flower extract on NO production, a pro-inflammatory radical produced by nitric oxide synthase (iNOS) and highly released by innate immune cells in inflammatory-related pathologies. NO production was evoked by the Toll-like receptor 4 agonist lipopolysaccharide (LPS) in macrophages, using concentrations that did not compromise cells viability. This ingredient exhibited a dose-dependent NO inhibition, reaching 50% at 147 μL/mL without cytotoxicity. Together with previous literature, these results provide experimental evidence on the anti-inflammatory properties of calendula flower extract, as well as its usefulness in cosmetics with soothing properties and adjunctive skin care in the treatment of the diseases associated with dysregulation of the NO signaling cascade.