Janus kinase (JAK) inhibitors for the treatment of skin and hair disorders: a review of literature

What is novel in the clinical management of pemphigus vulgaris?

INTRODUCTION

Pemphigus, an uncommon autoimmune blistering disorder affecting the skin and mucous membranes, currently with mortality primarily attributed to adverse reactions resulting from treatment protocols. Additionally, the existing treatments exhibit a notable recurrence rate. The high incidence of relapse and the considerable adverse effects associated with treatment underscore the imperative to explore safer and more effective therapeutic approaches. Numerous potential therapeutic targets have demonstrated promising outcomes in trials or preliminary research stages. These encompass anti-CD-20 agents, anti-CD-25 agents, TNF-α inhibition, FAS Ligand Inhibition, FcRn inhibition, BAFF inhibition, Bruton's tyrosine kinase (BTK) inhibition, CAAR T Cells, JAK inhibition, mTOR inhibition, abatacept, IL-4 inhibition, IL-17 inhibition, IL-6 inhibition, polyclonal Regulatory T Cells, and autologous hematopoietic stem cell transplantation.

AREAS COVERED

The most significant studies regarding the impact and efficacy of the mentioned treatments on pemphigus were meticulously curated through a comprehensive search conducted on the PubMed database. Moreover, the investigations of interest cited in these studies were also integrated.

EXPERT OPINION

The efficacy and safety profiles of the other treatments under discussion do not exhibit the same level of robustness as anti-CD20 therapy, which is anticipated to endure as a critical element in pemphigus treatment well into the foreseeable future.

What can we learn from treatments of oral lichen planus?

Oral lichen planus (OLP), a T-lymphocyte-mediated disease of the oral mucosa, has a complex pathogenesis that involves a number of factors. The disease is characterized by recurrent episodes and requires continuous follow up, and there is no curative treatment available. Erosive lichen planus, among others, has a risk of malignant transformation and requires standardized treatment to control its progression. Different clinical subtypes of oral lichen planus require appropriate treatment. Pharmacological treatments are the most widely available and have the greatest variety of options and a number of novel pharmacological treatments are presented as highlights, including JAK enzyme inhibitors. The second is photodynamic therapy, which is the leading physiological treatment. In addition, periodontal treatment and psychological treatment should not be neglected. In this review, we briefly discuss the most recent developments in therapies for oral lichen planus after summarizing the most widely used clinical treatments, aiming to provide different proposals for future clinical treatment.

Analysis of the association between Janus kinase inhibitors and malignant skin tumors using the Food and Drug Administration Adverse Event Reporting System

BACKGROUND

Malignant skin tumors are adverse events of concern regarding Janus kinase (JAK) inhibitors.

AIM

This study aimed to evaluate the association between JAK inhibitors and adverse events of malignant skin tumors, and to characterize the main features.

METHOD

Data (2012-2021) were collected using the US Food and Drug Administration Adverse Event Reporting System (FAERS). Adverse event cases of JAK inhibitors as the primary suspected drug were extracted for further analysis. Disproportionality analysis evaluated the association between JAK inhibitors and malignant skin tumor events by estimating the reporting odds ratio (ROR) and the information component (IC) with 95% confidence intervals (95% CI).

RESULTS

A total of 142,673 cases with JAK inhibitors as a primary suspected drug were collected, including 1400 malignant skin tumor events. Ruxolitinib, upadacitinib, tofacitinib, and baricitinib were included in the disproportionality analysis. Three JAK inhibitors were associated with malignant skin tumor events, namely ruxolitinib (ROR 5.40, 95% CI 5.03-5.81; IC 2.39, 95% CI 2.14-2.62), upadacitinib (ROR 4.79, 95% CI 4.03-5.71; IC 2.24, 95% CI 1.62-2.77), and tofacitinib (ROR 1.67, 95% CI 1.53-1.83; IC 0.73, 95% CI 0.43-1.02). The median time to onset time was 378.5 days.

CONCLUSION

We found association between malignant skin tumors and ruxolitinib, upadacitinib, and tofacitinib. More attention should be paid to these events when prescribing JAK inhibitors in clinical practice.

Effect of Janus Kinase 3 Inhibitor on Sebaceous Gland Regeneration during Skin Wound Healing

BACKGROUND

Janus kinase (Jak) 3 has recently been shown as a beneficial target for the treatment of chronic inflammatory diseases, such as psoriasis and alopecia areata. The role of Jak3 in tissue repair and remodeling is emerging.

OBJECTIVE

This study aimed to investigate the role of Jak3 signaling in the remodeling of the sebaceous gland (SG) during skin wound repair, and the development of in vitro SGs.

METHODS

Mouse skin tissue (ICR mouse) was obtained from the recovered skin eight days after a 4 mm biopsy punch wound. To observe the role of Jak3, the selective inhibitors WHI-p131 and PF06651600 was administered. Formation of in vitro SG was examined using primary sebocyte cultures obtained postnatally from 3-day-old mice.

RESULTS

The data showed that SGs showed highly positive signals with anti-isolectin B4, which also used for detection of angiogenetic vessels and the basal epidermis. Isolectin B4 could be a good indicator of SGs. The Jak3 inhibitors significantly reduced the area and volume of SG remodeling with reduced expression of p-Jak3. In addition, the area of cultured intact SG in vitro was significantly decreased in a concentration-dependent manner by Jak3 inhibition.

CONCLUSION

These data showed that Jak3 signaling is a potent regulator to develop SGs. Jak3 inhibition did not decrease the number of sebocytes in SGs but decreased the area and volume of SG remodeling. Therefore, Jak3 inhibition may be a potential target for the treatment of SG hyperplasia and associated skin diseases.

Selective Janus kinase 1 inhibition resolves inflammation and restores hair growth offering a viable treatment option for alopecia areata

Background

Janus Kinase (JAK) inhibition has recently demonstrated therapeutic efficacy in both restoring hair growth and resolving inflammation in Alopecia Areata (AA). These effects are dose dependent and mainly efficacious at ranges close to a questionable risk profile.

Objectives

We explored the possibility to separate the beneficial and adverse effects of JAK inhibition by selectively inhibiting JAK1 and thereby avoiding side effects associated with JAK2 blockade.

Methods

The C3H/HeJ mouse model of AA was used to demonstrate therapeutic efficacy in vivo with different regimens of a selection of JAK inhibitors in regards to systemic versus local drug exposure. Human peripheral blood lymphocytes were stimulated in vitro to demonstrate translation to the human situation.

Results

We demonstrate that selective inhibition of JAK1 produces fast resolution of inflammation and complete restoration of hair growth in the C3H/HeJ mouse model of AA. Furthermore, we show that topical treatment does not restore hair growth and that treatment needs to be extended well beyond that of restored hair growth in order to reach treatment-free remission. For translatability to human disease, we show that cytokines involved in AA pathogenesis are similarly inhibited by selective JAK1 and pan-JAK inhibition in stimulated human peripheral lymphocytes and specifically in CD8+ T cells.

Conclusion

This study demonstrates that systemic exposure is required for efficacy in AA and we propose that a selective JAK1 inhibitor will offer a treatment option with a superior safety profile to pan-JAK inhibitors for these patients.

Efficacy and safety of JAK inhibitors in the treatment of psoriasis and psoriatic arthritis: a systematic review and meta-analysis

Background

JAK inhibitors are a relatively new class of medications that may be useful in the treatment of moderate-to-severe psoriasis and psoriatic arthritis (PsA). The objective of this study was to determine the efficacy of several JAK inhibitors in treating psoriasis and PsA and examine safety concerns.

Methods

MEDLINE, Cochrane and EMBASE were searched for randomized controlled trials and observational studies comparing any JAK inhibitor to placebo. The primary outcomes were a 75% improvement in the Psoriasis Area and Severity Index (PASI75) and a 20% improvement in the American College of Rheumatology composite score (ACR20). A secondary outcome was the proportion of patients achieving a “0” or “1” on the static Physician Global Assessment scale. Odds ratios were used to compare the proportion of patients reaching these targets in the max dose intervention group vs. the placebo group. A random effects model was used to account for heterogeneity.

Results

In total, 15 RCTs were included in the study and no observational studies. This encompassed 6757 patients in total. When the results were combined, the calculated odds ratio for PASI75 amongst tofacitinib vs. placebo was OR 14.35 [95%CI 7.65, 26.90], for PASI75 amongst non-tofacitinib JAK inhibitors vs. placebo it was OR 6.42 [95%CI 4.89, 8.43], for ACR20 amongst all JAK inhibitors versus placebo was OR 5.87 [95%CI 4.39, 7.85]. There was no significant difference in prevalence of serious adverse events between intervention and control in any of these studies.

Conclusion

JAK inhibitors show promise for safely treating moderate-to-severe psoriasis and psoriatic arthritis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41927-022-00287-7.

Survey of extracellular communication of systemic and organ-specific inflammatory responses through cell free messenger RNA profiling in mice

Background

Inflammatory and immune responses are essential and dynamic biological processes that protect the body against acute and chronic adverse stimuli. While conventional protein markers have been used to evaluate systemic inflammatory response, the immunological response to stimulation is complex and involves modulation of a large set of genes and interacting signalling pathways of innate and adaptive immune systems. There is a need for a non-invasive tool that can comprehensively evaluate and monitor molecular dysregulations associated with inflammatory and immune responses in circulation and in inaccessible solid organs.

Methods

Here we utilized cell-free messenger RNA (cf-mRNA) RNA-Seq whole transcriptome profiling and computational biology to temporally assess lipopolysaccharide (LPS) induced and JAK inhibitor modulated inflammatory and immune responses in mouse plasma samples.

Findings

Cf-mRNA profiling displayed a pattern of systemic immune responses elicited by LPS and dysregulation of associated pathways. Moreover, attenuation of several inflammatory pathways, including STAT and interferon pathways, were observed following the treatment of JAK inhibitor. We further identified the dysregulation of liver-specific transcripts in cf-mRNA which reflected changes in the gene-expression pattern in this generally inaccessible biological compartment.

Interpretation

Using a preclinical mouse model, we demonstrated the potential of plasma cf-mRNA profiling for systemic and organ-specific characterization of drug-induced molecular alterations that are associated with inflammatory and immune responses.

Funding

Molecular Stethoscope.

Concurrent bullous pemphigoid and plaque psoriasis successfully treated with Janus kinase inhibitor Baricitinib

We report a case of aggressive bullous pemphigoid (BP) concurrent with plaque psoriasis successfully treated with Janus kinase inhibitor Baricitinib. The 83-year-old Chinese man suffered ten years of psoriasis and developed bullous pemphigoid with typical intense blisters and significantly elevated serum anti-BP180 autoantibodies. Due to concerns on his poor health conditions including stage III hypertension and potential serious side effects of standard treatment with systematic steroid, he was given Baricitinib orally 4mg/day. Significant improvement in skin lesions and pruritus was noted following treatment for 12falseweeks, from which the dose of Baricitinib was halved and continued for an additional 12falseweeks. He showed a complete remission of both bullous and psoriatic lesions without any adverse effects at the 24-week follow-up visit. Our observation suggests a potential of Baricitinib as a new alternative therapeutic option for concurrent plaque psoriasis and bullous pemphigoid or either of them. This article is protected by copyright. All rights reserved.

Baricitinib is Effective in Treating Progressing Vitiligo in vivo and in vitro

Objective

To evaluate the clinical efficacy and safety of baricitinib, a Janus kinase (JAK) inhibitor, in treating patient with progressing vitiligo, and to further explore the regulation of baricitinib on melanocytes (MCs) in vitro.

Methods

Four patients with progressing vitiligo were treated with oral baricitinib for a total of 12 weeks. MCs were cultured in vitro and irradiated by high-dose ultraviolet B (UVB, 150mJ/cm²) to make an MC damaged model (MC-Ds). Baricitinib was added at a final concentration of 25 μM. Dopamine staining and NaOH method were used to measure the tyrosinase activity and melanin level, respectively, real-time quantitative polymerase chain reaction (RT-qPCR) was used to measure the mRNA levels of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1).

Results

Significant re-pigmentation was observed in the week 12 without obvious side effects. Depigmentation occurred in 2 patients at the 3-month follow-up. Laboratory research found that higher doses of UVB irradiation (150mJ/cm²) could decrease melanin content of MCs, baricitinib (25 μM) could significantly promote tyrosinase activity, melanin content, and TYR, TRP-1 gene expression of MC-Ds.

Conclusion

Our preliminary study showed that baricitinib was effective and safe in treating progressing vitiligo. Baricitinib could promote tyrosinase activity, melanin content and TYR, TRP1 gene expression of MC-Ds in vitro.

Rheumatoid Arthritis and JAK-STAT Inhibitors: Prospects of Topical Delivery

Abstract:

Rheumatoid arthritis (RA) is the most common musculoskeletal disease in the world. The clinical prospects have increased tremendously since the advent of biological agents as therapy options. NSAIDs such as indomethacin, celecoxib, and etoricoxib are used often in the treatment of RA but off-target effects decreased their use. DMARDs such as methotrexate and etanercept were also effective in the treatment of RA, but tolerance to methotrexate developed in many cases. Janus kinase inhibitors (JAKi) have also gained popularity as a treatment option for rheumatoid arthritis. Tofacitinib is the foremost JAK inhibitor that is used to treat RA as an individual agent or in combination with other DMARDs. The most frequently used route of administration for JAKi is oral. Since oral formulations of JAK inhibitors have a number of health hazards, such as systemic toxicity and patient noncompliance, topical formulations of JAK inhibitors have emerged as a preferable alternative for administering JAK inhibitors. Tofacitinib delivered topically, seems to have the potential to eliminate or reduce the occurrences of negative effects when compared to tofacitinib taken orally. Given the scarcity of knowledge on the techniques for topical distribution of JAKi, more effort will be required to develop a stable topical formulation of JAKi to address the limitations of oral route. The current review looks at JAK inhibitors and the ways that have been used to generate topical formulations of them.

Acne exacerbation after tofacitinib treatment for alopecia areata

The major discovery of the novel therapeutic Janus kinase (JAK) inhibitors has been implicated in several dermatological diseases. Recently, studies have shown the efficacy and encouraging results of oral JAK inhibitors as a treatment for alopecia areata (AA). Due to the novelty of this treatment, potential side effects are not fully explored. In this paper, we present a case of a 28-year-old male with a 10-year history of alopecia totalis (AT) treated successfully with tofacitinib with encouraging effects on hair regrowth; however, a significant worsening of the patient’s facial acne was observed four months after AT treatment initiation. JAK inhibitors have promising results in the management of different dermatological conditions including moderatesevere forms of AA with few reported adverse events. Acne exacerbation is a unique observed adverse effect of this therapy. More thorough larger sized studies are needed to further characterize the association between acne exacerbation and the use of JAK inhibitors.

Janus Kinase Inhibitors and Non-Melanoma Skin Cancer

OPINION STATEMENT

JAK (janus kinase) inhibitors are becoming increasingly prescribed for various conditions from dermatologic diseases to graft versus host disease in bone marrow transplant recipients. This class of drugs has been found to be truly life-changing for many, though they are not without potential adverse effects. While JAK inhibitors have not been shown to significantly increase the risk of non-melanoma skin cancer (NMSC) in large scale clinical trials, NMSC is one of the most concerning possible adverse events, and there have been several reported cases of aggressive squamous cell carcinomas, especially in our already immunosuppressed patient populations. In these patients, it is incredibly important that patients are on the lowest possible dosage of the JAK inhibitor. In addition, these patients must be routinely screened by a dermatologist with a comprehensive skin exam to ensure early detection if skin cancer was to develop. For those patients diagnosed with skin cancer, early intervention is key to optimize outcomes, and at times, multi-disciplinary care coordination is needed. In the future, large-scale studies with longer follow-up of patients would help determine whether JAK inhibitors significantly increase the risk of NMSC.

Frontal Fibrosing Alopecia and Autoimmune Disorders in a Hispanic Female

Frontal fibrosing alopecia (FFA) is a cicatricial alopecia characterized by hairline recession. Multiple autoimmune pathologies have been reported in patients with FFA. Despite the fact that FFA etiology remains unknown, there has been described an association with autoimmune disorders probably caused by an altered activity of cytotoxic CD8 T lymphocytes. Moreover, other autoimmune pathologies develop TH1 and TH17 response. Genetics could be responsible, in part, for the role of multiple simultaneous autoimmune disorders. Herein, we describe a case of a female patient with vitiligo, lichen sclerosus, and autoimmune hypothyroidism who developed a pruritic band-like recession of the frontal hairline. More research is needed in this area since autoimmune events in these patients may not be a mere coincidence.

Abrocitinib for the treatment of atopic dermatitis

INTRODUCTION

Janus kinase (JAK) inhibitors are emerging treatments in dermatology. Also known as JAKinibs, these agents target JAK-signal transducers and activators of transcription (JAK-STAT) pathway for intracellular signaling. Among the various immune-mediated inflammatory skin diseases that the JAK-STAT pathway plays a role in, atopic dermatitis (AD) is an important one. AD has a complex and multifactorial pathophysiology that is not fully understood. Immune dysregulation can result in epidermal barrier disruption and intensify atopic dermatitis. The newly developed abrocitinib (PF-04965842) selectively inhibits the JAK1 protein, which is believed to modulate cytokines involved in AD pathophysiology.

AREAS COVERED

This work is a review of the current literature related to abrocitinib, including the phase I, II, and III clinical trials, for the treatment of AD. Immunological considerations of abrocitinib and JAK inhibition are also explored.

EXPERT OPINION

Abrocitinib is among the first JAK inhibitors evaluated for the treatment of AD. Similar to other JAKinhibs that mechanistically block the signaling of several cytokines, abrocitinib possesses both positive and negative clinical attributes. Nonetheless, the risk-benefit profile of abrocitinib remains favorable. Up to 61% of AD patients achieve an EASI 75 response while a minority of responding patients experience mild to moderate symptoms related to tolerability.

Genome-wide selective sweep analysis of the high-altitude adaptability of yaks by using the copy number variant

The domestic yak (Bos grunniens) from the Qinghai-Tibet Plateau is an important animal model in high-altitude adaptation studies. Here, we performed the genome-wide selective sweep analysis to identify the candidate copy number variation (CNV) for the high-altitude adaptation of yaks. A total of 531 autosomal CNVs were determined from 29 yak genome-wide resequencing data (15 high- and 14 low-altitude distributions) by using a CNV caller with a CNV identification interval > 5 kb, CNV silhouette score > 0.7, and minimum allele frequency > 0.05. Most high-frequency CNVs were located at the exonic (44.63%) and intergenic (46.52%) regions. In accordance with the results of the selective sweep analysis, 7 candidate CNVs were identified from the interaction of the top 20 CNVs with highest divergence from the F _ST and V _ST between the low (LA) and high (HA) altitudes. Five genes (i.e., GRIK4, IFNLR1, LOC102275985, GRHL3, and LOC102275713) were also annotated from the seven candidate CNVs and their upstream and downstream ranges at 300 kb. GRIK4, IFNLR1, and LOC102275985 were enriched in five known signal pathways, namely, glutamatergic synapse, JAK-STAT signaling pathway, cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and olfactory transduction. These pathways are involved in the environmental adaptability and various physiological functions of animals, especially the physiological regulation under a hypoxic environment. The results of this study advanced the understanding of CNV as an important genomic structure variant type that contributes to HA adaptation and helped further explain the molecular mechanisms underlying the altitude adaptability of yaks.

Pruritus in pediatric patients with atopic dermatitis: a multidisciplinary approach - summary document from an Italian expert group

Given the inadequate overall awareness of the main disease features and treatment modalities of pruritus in pediatric patients with atopic dermatitis, a multidisciplinary Italian expert group met with the major aim of increasing knowledge of the condition for improved diagnosis and better management among specialists involved in disease management. Herein, the overall features of the condition are reviewed, along with its etiopathogenesis and symptoms. Likewise, management options are summarized, emphasizing the need for a multidisciplinary approach, minimally composed of a management team that includes a pediatrician, dermatologist, psychologist, play assistant, and dedicated nurse. In addition to more traditional therapies such as emollients as highlighted by European guidelines, therapeutic patient education in a group or individually is highly encouraged as it helps patients and their parents to better understand the disease and provide practical guidance for dressing and bandaging. It can also aid in outlining coping strategies for itching and sleep disturbance. The utility of distraction techniques should also be stressed as such educational interventions involving the child and their parents can substantially improve the overall quality of life. All approaches should be tailored according to patient age and clinical features and requires individualized strategy to ensure good adherence by both children and their parents. Thus, a holistic approach embracing systemic, topical and psychological interventions is advocated in order to provide patients and their caregivers the best possible care.

Scoping Review on the Use of Drugs Targeting JAK/STAT Pathway in Atopic Dermatitis, Vitiligo, and Alopecia Areata

INTRODUCTION

The JAK/STAT signaling pathway is involved in the immune-mediated inflammatory skin diseases atopic dermatitis (AD), vitiligo, and alopecia areata (AA), and represents a potential target when developing treatments. So far, no drugs targeting this pathway have been approved for the treatment of dermatological diseases. We reviewed the use of drugs blocking the JAK/STAT pathway in the aforementioned diseases.

METHODS

An a priori protocol was published. We used Joanna Briggs Institute Reviewer's Manual methodology to conduct the review and PRISMA Extension for Scoping Review (PRISMA-ScR) to report results. MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science databases were searched in a three-step approach on April 2019 by two researchers.

RESULTS

Ninety-six mainly multicenter observational studies were included (66, 10, and 20 studies on AA, vitiligo, and AD, respectively). Tofacitinib and ruxolitinib were mainly used for the three diseases, and also upadacitinib, abrocitinib, baricitinib, cerdulatinib, delgocitinib, gusacitinib for AD, and baricitinib, PF-06700841, and PF-06651600 for AA. All patients with AD improved, whereas patients with vitiligo and patients with AA showed varied responses, including unresponsive cases. The safety profiles were similar for all drugs and diseases, mainly comprising mild or no adverse events.

CONCLUSIONS

Evidence on the efficacy and safety of drugs targeting the JAK/STAT pathway for the treatment of patients with AD, vitiligo, or AA is increasing but is still of low quality.

Oral Tofacitinib: Contemporary Appraisal of Its Role in Dermatology

Tofacitinib, an oral Janus kinase inhibitor (Jakinib), is an emerging treatment modality whose well-established efficacy in systemic inflammatory diseases is now being actively explored for cutaneous disorders (arising due to the patient's dysimmune responses) that are not responding to and/or sustaining intolerable adverse effects with the classical immunosuppressives and other targeted therapies such as the biologics. The most common dermatoses for which oral as well as topical Jakinibs such as tofacitinib have been evaluated and are being used albeit as an off-label indication include psoriasis, psoriatic arthritis, alopecia areata, vitiligo, and atopic dermatitis. This article provides a succinct review on the current status of oral tofacitinib in dermatology through literature search of PubMed database and stresses on the need for further evidence generation to define the drug's place in the therapeutic arsenal of dysimmune cutaneous disorders.

Drugs targeting the JAK/STAT pathway for the treatment of immune-mediated inflammatory skin diseases: protocol for a scoping review

INTRODUCTION

The Janus kinase and Signal Transducer and Activator of Transcription protein (JAK/STAT) pathway is known to be involved in inflammatory and neoplastic skin diseases, like psoriasis, atopic dermatitis, alopecia areata, vitiligo and melanoma. Improved knowledge of the components of this pathway has allowed the development of drugs, which act by inhibiting the pathway, blocking specific components. This offers new therapeutic opportunities. Although evidence on the use of JAK/STAT blockades in dermatological diseases is growing, none have been approved for use in treating skin diseases. The aim of this study is to develop an a priori protocol to broadly review the available evidence on the use of drugs targeting the JAK/STAT pathway in the treatment of dermatological diseases.

METHODS AND ANALYSIS

For the conduction of the scoping review protocol, we will employ an established scoping review methodology described in the Joanna Briggs Institute manual. This methodology outlines a five-stage approach: (1) identify the research question; (2) identify relevant studies; (3) select studies; (4) chart the data and (5) collate, summarise and report the results, with an optional consultation exercise. Finally, we will use the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews to present the results.

ETHICS AND DISSEMINATION

Since this is a review of the literature, ethics approval is not indicated. We will disseminate the findings from this study in publications in peer-reviewed journals as well as presentations at relevant national and international conferences.

The Use of Janus Kinase Inhibitors in Vitiligo: A Review of the Literature

Vitiligo is a common acquired depigmenting disorder characterized by the development of white macules and patches due to the loss of melanocytes. Patients with vitiligo can be stigmatized by society, making the disease a source of psychological stress that can considerably affect quality of life. The goal of vitiligo treatment is to obtain skin repigmentation in the majority of cases, and less commonly to depigment the remaining normal skin. There is no consistent, long-term, durable therapy for vitiligo for all patients, highlighting the unmet need for new safe and effective therapies to control this disease. Recently, JAK inhibitors have been explored as a promising novel treatment option in vitiligo. The JAK and signal transducers and activators of transcription (STAT) pathway is an attractive therapeutic target because IFN-γ-dependent cytokines produced through this pathway have been implicated in the pathogenesis of disease. This literature review describes vitiligo pathophysiology, explains the usefulness of the JAK inhibitors for treatment, and summarizes published case reports, case series, and open-label studies. Research outlined here shows JAK inhibitors in patients with vitiligo have a favorable safety profile and effectively produce repigmentation of lesions, especially with concomitant ultraviolet exposure. Additional studies are required to confirm efficacy, establish safety, and investigate durability of repigmentation.

Frontal fibrosing alopecia: An update on the hypothesis of pathogenesis and treatment

Frontal fibrosing alopecia (FFA) is a relatively new scarring alopecia that is considered a variant of lichen planopilaris (LPP) with no recognized promising treatments. In this study, we tried to clarify the underlying signaling pathways and their roles in the pathogenesis and progression of FFA. Because of several differences in clinical manifestations, response to treatments, and pathological findings, these two conditions could be differentiated from each other. Taking into account the already discussed signaling pathways and involved players such as T cells, mast cells, and sebaceous glands, different possible therapeutic options could be suggested. In addition to treatments supported by clinical evidence, such as 5 alpha-reductase inhibitors, topical calcineurin inhibitors, hydroxychloroquine, peroxisome proliferator-activated receptor gamma agonists, and oral retinoid agents, various other treatment strategies and drugs, such as phototherapy, Janus kinase inhibitors, dehydroepiandrosterone, sirolimus, cetirizine, and rituximab, could be suggested to mitigate disease progression. Of course, such lines of treatment need further evaluation in clinical trials.

Janus Kinase Inhibitors for the Treatment of Severe Alopecia Areata: An Open-Label Comparative Study

<b><i>Background:</i></b> Alopecia areata (AA) is a common autoimmune disorder characterized by patchy hair loss. There are many treatments available for AA. However, treatments of severe forms of AA are not satisfactory. Recently, oral Janus kinase (JAK) inhibitors were found to be effective for the treatment of severe AA variants. <b><i>Objective:</i></b> The aim of this work was to evaluate and compare the efficacy, side effects, and durability of two oral JAK inhibitor medications (ruxolitinib and tofacitinib) in the treatment of severe AA. <b><i>Methods:</i></b> This study included 75 patients with AA with more than 30% scalp hair loss, alopecia totalis, and alopecia universalis randomized into 2 groups. The first group (<i>n</i> = 38) received ruxolitinib 20 mg twice daily, and the second group (<i>n</i> = 37) received oral tofacitinib 5 mg twice daily. The treatment continued for 6 months followed by 3 months of follow-up off therapy. Efficacy of treatment was assessed by monitoring the change in the Severity of Alopecia Tool (SALT) score. <b><i>Results:</i></b> Both tofacitinib and ruxolitinib induced remarkable hair regrowth, with a mean change in SALT score of 93.8 ± 3.25 in the ruxolitinib group and 95.2 ± 2.69 in the tofacitinib group. However, the ruxolitinib group showed a shorter duration for initial hair regrowth. There was no statistically significant difference between the groups regarding hair regrowth at the end of the 6-month treatment and relapse rate at the end of the 3-month follow-up. Around two thirds of cases experienced relapse. Both drugs were well tolerated, with no reported serious adverse effects. <b><i>Conclusion:</i></b> Both ruxolitinib and tofacitinib could be considered effective and well-tolerated treatments for extensive AA.

Alopecia areata: a review of disease pathogenesis

BACKGROUND

Alopecia areata is a disorder that results in nonscarring hair loss. The psychological impact can be significant, leading to feelings of depression and social isolation. Objectives In this article, we seek to review the pathophysiological mechanisms proposed in recent years in a narrative fashion.

METHODS

We searched MEDLINE and Scopus for articles related to alopecia areata, with a particular emphasis on its pathogenesis.

RESULTS

The main theory of alopecia areata pathogenesis is that it is an autoimmune phenomenon resulting from a disruption in hair follicle immune privilege. What causes this breakdown is an issue of debate. Some believe that a stressed hair follicle environment triggers antigen presentation, while others blame a dysregulation in the central immune system entangling the follicles. Evidence for the latter theory is provided by animal studies, as well investigations around the AIRE gene. Different immune-cell lines including plasmacytoid dendritic cells, natural killer cells and T cells, along with key molecules such as interferon-γ, interleukin-15, MICA and NKG2D, have been identified as contributing to the autoimmune process.

CONCLUSIONS

Alopecia areata remains incurable, although it has been studied for years. Available treatment options at best are beneficial for milder cases, and the rate of relapse is high. Understanding the exact mechanisms of hair loss in alopecia areata is therefore of utmost importance to help identify potential therapeutic targets.

Entangled Conditional Adversarial Autoencoder for de Novo Drug Discovery

Modern computational approaches and machine learning techniques accelerate the invention of new drugs. Generative models can discover novel molecular structures within hours, while conventional drug discovery pipelines require months of work. In this article, we propose a new generative architecture, entangled conditional adversarial autoencoder, that generates molecular structures based on various properties, such as activity against a specific protein, solubility, or ease of synthesis. We apply the proposed model to generate a novel inhibitor of Janus kinase 3, implicated in rheumatoid arthritis, psoriasis, and vitiligo. The discovered molecule was tested in vitro and showed good activity and selectivity.

Indirubin ameliorates imiquimod-induced psoriasis-like skin lesions in mice by inhibiting inflammatory responses mediated by IL-17A-producing γδ T cells

OBJECTIVES

Indirubin (IR) is a bisindole compound extracted from the leaves of Chinese herb Indigo Naturalis. Indigo Naturalis has been widely used in traditional Chinese medicine to treat inflammatory and autoimmune diseases. Psoriasis is a chronic immune-mediated inflammatory skin disease in which γδ T cells play an important role. This study aims to determine the immunoregulatory effects and the underlying mechanisms of Indirubin in psoriasis-related inflammatory responses.

METHODS

BALB/c mice with imiquimod (IMQ)-induced psoriasis-like dermatitis were treated with saline (Model), 1 mg/kg methotrexate (MTX) that serves as a positive control, or 12.5, 25 and 50 mg/kg Indirubin(IR) intragastrically. Keratinocytes proliferation, inflammatory cells infiltration, the expression of inflammatory cytokines and Jak/Stat pathway-related proteins in the skin lesion were examined. The abundance of γδ T cells in lymph nodes and spleen was determined by flow cytometry. The IL-17 expression and secretion, and the activation of Jak3/Stat3 pathways in in vitro cultured γδ T cell were tested.

RESULTS

Indirubin ameliorated keratinocyte proliferation, reduced the infiltration of CD3⁺ T cells, IL-17 A-producing γδ T cells, and CD11b⁺ neutrophils, inhibited the mRNA expression of Il1, Il6, Il23, Il17a and Il22, and the protein expression of Jak/Stat pathway-related molecules in the skin lesion. Indirubin also reduced the abundance of γδ T cell and CCR6⁺ γδ T cells (the major IL-17 A producer) in spleen and lymph nodes. In cultured γδ T cells, Indirubin inhibited the mRNA expression of Il17a and Ifng, and the secretion of IL-17 A, while suppressed the activation of Jak3/Stat3 pathways.

CONCLUSION

Indirubin alleviates IMQ-induced psoriasis-like dermatitis mainly through reducing the inflammatory responses mediated by IL-17 A-producing γδ T cells involving Jak3/Stat3 activation. Our results highlighted the novel mechanisms by which Indirubin ameliorates psoriasis-related inflammatory responses, supporting its therapeutic potential.

The etiopathogenesis of atopic dermatitis: barrier disruption, immunological derangement, and pruritus

Atopic dermatitis (AD) is a common chronic skin inflammatory disorder characterized by recurrent eczema accompanied by an intractable itch that leads to an impaired quality of life. Extensive recent studies have shed light on the multifaceted pathogenesis of the disease. The complex interplay among skin barrier deficiency, immunological derangement, and pruritus contributes to the development, progression, and chronicity of the disease. Abnormalities in filaggrin, other stratum corneum constituents, and tight junctions induce and/or promote skin inflammation. This inflammation, in turn, can further deteriorate the barrier function by downregulating a myriad of essential barrier-maintaining molecules. Pruritus in AD, which may be due to hyperinnervation of the epidermis, increases pruritogens, and central sensitization compromises the skin integrity and promotes inflammation. There are unmet needs in the treatment of AD. Based on the detailed evidence available to date, certain disease mechanisms can be chosen as treatment targets. Numerous clinical trials of biological agents are currently being conducted and are expected to provide treatments for patients suffering from AD in the future. This review summarizes the etiopathogenesis of the disease and provides a rationale for choosing the novel targeted therapy that will be available in the future.