Alopecia Areata: Current Treatments and New Directions

Amygdalin ameliorates alopecia areata on C3H/HeJ mice by inhibiting inflammation through JAK2/STAT3 pathway

BACKGROUND

Evidence has demonstrated that Chinese medicine formula Xuefu Zhuyu decoction can markedly promote the formation of new hair in patients and mice with alopecia areata (AA). Amygdalin is one of the active components of Xuefu Zhuyu decoction, but its therapeutic effects and the underlying mechanisms on AA remains largely unrevealed.

PURPOSE

Therefore, this study aims to investigate the therapeutic effects and to probe its molecular mechanisms of inflammation and immune regulation on AA model of C3H/HeJ mice.

STUDY DESIGN

The C3H/HeJ female mice were divided into control, AA, rusolitinib (60 mg/kg), and amygdalin groups (60, 90, and 120 mg/kg, 0.2 ml/10 g, i.g.).

METHODS

The optical microscope was used to observe the feature of the local skin, and the number of lanugo and terminal hair. H&E staining was performed to determine the degree of pathological damage to the skin. ELISA was performed to detect levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in mice serum. Flow cytometry was carried out to analyze the CD4+CD25+FOXP3+, CD4+ and CD8+ of skin tissue. And the levels of CD4+ and CD8+, p-JAK/JAK2, p-STAT3/STAT, and SOCS3 were detected by immunohistochemistry. Western blot and qRT-PCR were employed to examine the expression levels of IL-6, TNF-α, IFN-γ, JAK2, p-JAK, STAT, p-STAT3 and SOCS3 proteins and genes in skin tissues.

RESULTS

Compared with AA group, amygdalin immensely increased the number of vellus hairs and decreased the number of terminal hairs determined by skin microscopy and H&E staining. ELISA, Western blot and qRT-PCR data showed that the levels of IL-6, TNF-α and IFN-γ in serum and skin tissues of AA mice were significantly increased, while amygdalin administration dramatically restrained the contents of the three pro-inflammatory factors. Flow cytometry and immunohistochemistry hinted that amygdalin observably enhanced the number of CD4+CD25+FOXP3+ and CD4+ cells, while inhibited the number of CD8+ positive cells in mice with AA. Moreover, amygdalin signally reduced JAK2/STAT3 pathway-related protein and gene levels in AA mice.

CONCLUSION

Amygdalin could inhibit inflammatory response and improve immune function in the treatment of AA. The underlying molecular mechanism may be related to inhibition of JAK2/STAT3 pathway.

Discovery of a novel and highly selective JAK3 inhibitor as a potent hair growth promoter

JAK-STAT signalling pathway inhibitors have emerged as promising therapeutic agents for the treatment of hair loss. Among different JAK isoforms, JAK3 has become an ideal target for drug discovery because it only regulates a narrow spectrum of γc cytokines. Here, we report the discovery of MJ04, a novel and highly selective 3-pyrimidinylazaindole based JAK3 inhibitor, as a potential hair growth promoter with an IC50 of 2.03 nM. During in vivo efficacy assays, topical application of MJ04 on DHT-challenged AGA and athymic nude mice resulted in early onset of hair regrowth. Furthermore, MJ04 significantly promoted the growth of human hair follicles under ex-vivo conditions. MJ04 exhibited a reasonably good pharmacokinetic profile and demonstrated a favourable safety profile under in vivo and in vitro conditions. Taken together, we report MJ04 as a highly potent and selective JAK3 inhibitor that exhibits overall properties suitable for topical drug development and advancement to human clinical trials.

Lasers in the management of alopecia: a review of established therapies and advances in treatment

Alopecia, also known as hair loss, is a highly prevalent condition affecting millions of men and women in the United States and worldwide, making it one of the most common complaints by patients presenting to a dermatologist. The symptomology on the presentation of alopecia can be highly variable, ranging from diffuse thinning of hair, discrete and localized patches completely absent of hair, or noticing significant shedding when brushing and showering. Although alopecia does not have a direct negative health impact on patients, it is nonetheless a debilitating disease as it can profoundly impact an individual's self-image and psychosocial well-being. There are multiple treatment options available to patients with alopecia, and they are typically tailored to the patient's needs and preferences. The most common of these is the Food and Drug Administration-approved drugs for alopecia, minoxidil, and finasteride. However, both of these are known to be partially efficacious for all patients, so clinicians often use different modalities in conjunction with them, in particular laser-based therapies. This review article will provide a comprehensive assessment of lasers and other light therapies that may be used to manage the two most common types of alopecia: androgenetic alopecia and alopecia areata.

Pathogenesis of Alopecia Areata and Vitiligo: Commonalities and Differences

Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment loss, respectively. In AA, inflammatory cell infiltrates are in the deep reticular dermis close to the hair bulb (swarm of bees), whereas in vitiligo the inflammatory infiltrates are in the epidermis and papillary dermis. Immune privilege collapse has been extensively investigated in AA pathogenesis, including the suppression of immunomodulatory factors (e.g., transforming growth factor-β (TGF-β), programmed death-ligand 1 (PDL1), interleukin-10 (IL-10), α-melanocyte-stimulating hormone (α-MSH), and macrophage migration inhibitory factor (MIF)) and enhanced expression of the major histocompatibility complex (MHC) throughout hair follicles. However, immune privilege collapse in vitiligo remains less explored. Both AA and vitiligo are autoimmune diseases that share commonalities in pathogenesis, including the involvement of plasmacytoid dendritic cells (and interferon-α (IFN- α) signaling pathways) and cytotoxic CD8+ T lymphocytes (and activated IFN-γ signaling pathways). Blood chemokine C-X-C motif ligand 9 (CXCL9) and CXCL10 are elevated in both diseases. Common factors that contribute to AA and vitiligo include oxidative stress, autophagy, type 2 cytokines, and the Wnt/β-catenin pathway (e.g., dickkopf 1 (DKK1)). Here, we summarize the commonalities and differences between AA and vitiligo, focusing on their pathogenesis.

Effectiveness and Predictive Factors of Response to Tofacitinib Therapy in 125 Patients with Alopecia Areata: A Single-centre Real-world Retrospective Study

Alopecia areata is an autoimmune disorder that greatly impacts patients' quality of life, and its management remains challenging. Tofacitinib is the first Janus kinase inhibitor to be approved for clinical use and is the most extensively studied. Several studies have demonstrated the clinical effectiveness of oral tofacitinib in treating patients with alopecia areata. However, despite being widely used in clinical practice, no prospective randomized controlled trials have been implemented and its indication criteria have not been thoroughly established. Moreover, little is known about the factors associated with response to therapy under real-world conditions. The aims of this retrospective cohort study of patients with alopecia areata treated with tofacitinib for 3 months were to assess the effectiveness of tofacitinib and to identify predictive factors of response to it. Primary outcome was the change in disease severity, as evaluated by Severity of Alopecia Tool (SALT) grade. A total of 125 patients with alopecia areata were included, the incidence of effectiveness was 83.2%, and 16.0% of patients achieved a result of complete remission. Total duration of alopecia areata and previous hair regrowth were independent predictors of response. Combined therapy was associated with relapse after discontinuation. No severe adverse event was observed. This study suggests that tofacitinib provides an effective treatment option for patients with alopecia areata, and that earlier intervention in the treatment of severe alopecia areata with tofacitinib may lead to better outcomes.