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Advances in Therapy Jul 2017Recent genetic and preclinical studies have increased our understanding of the immunopathogenesis of alopecia areata (AA). This has allowed expedited development of... (Review)
Review
Recent genetic and preclinical studies have increased our understanding of the immunopathogenesis of alopecia areata (AA). This has allowed expedited development of targeted therapies for the treatment of AA, and a paradigm shift in our approach and understanding of autoimmunity and the hair follicle. The synergy between preclinical studies, animal models, and translational studies has led to unprecedented advances in the treatment options for AA, ultimately benefiting patients who have had little recourse. In this review, we summarize the scientific field of contemporary AA research, and look forward to potential new technologies and developments.
Topics: Alopecia Areata; Animals; Drug-Related Side Effects and Adverse Reactions; Humans; Immunosuppressive Agents; Translational Research, Biomedical
PubMed: 28646392
DOI: 10.1007/s12325-017-0540-9 -
Expert Opinion on Drug Discovery Mar 2015Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of... (Review)
Review
INTRODUCTION
Hair loss or alopecia affects the majority of the population at some time in their life, and increasingly, sufferers are demanding treatment. Three main types of alopecia (androgenic [AGA], areata [AA] and chemotherapy-induced [CIA]) are very different, and have their own laboratory models and separate drug-discovery efforts.
AREAS COVERED
In this article, the authors review the biology of hair, hair follicle (HF) cycling, stem cells and signaling pathways. AGA, due to dihydrotesterone, is treated by 5-α reductase inhibitors, androgen receptor blockers and ATP-sensitive potassium channel-openers. AA, which involves attack by CD8(+)NK group 2D-positive (NKG2D(+)) T cells, is treated with immunosuppressives, biologics and JAK inhibitors. Meanwhile, CIA is treated by apoptosis inhibitors, cytokines and topical immunotherapy.
EXPERT OPINION
The desire to treat alopecia with an easy topical preparation is expected to grow with time, particularly with an increasing aging population. The discovery of epidermal stem cells in the HF has given new life to the search for a cure for baldness. Drug discovery efforts are being increasingly centered on these stem cells, boosting the hair cycle and reversing miniaturization of HF. Better understanding of the molecular mechanisms underlying the immune attack in AA will yield new drugs. New discoveries in HF neogenesis and low-level light therapy will undoubtedly have a role to play.
Topics: Administration, Topical; Alopecia; Animals; Drug Discovery; Hair; Hair Follicle; Humans; Immunotherapy; Pharmaceutical Preparations; Stem Cells
PubMed: 25662177
DOI: 10.1517/17460441.2015.1009892 -
American Family Physician Mar 2003Alopecia can be divided into disorders in which the hair follicle is normal but the cycling of hair growth is abnormal and disorders in which the hair follicle is... (Review)
Review
Alopecia can be divided into disorders in which the hair follicle is normal but the cycling of hair growth is abnormal and disorders in which the hair follicle is damaged. Androgenetic alopecia is the most common cause of hair loss in women. Other disorders include alopecia areata, telogen effluvium, cicatricial alopecia, and traumatic alopecias. The diagnosis is usually based on a thorough history and a focused physical examination. In some patients, selected laboratory tests or punch biopsy may be necessary. Topically administered minoxidil is labeled for the treatment of androgenetic alopecia in women. Corticosteroids and other agents are typically used in women with alopecia areata. Telogen effluvium is often a self-limited disorder. Because alopecia can be devastating to women, management should include an assessment for psychologic effects.
Topics: Administration, Topical; Alopecia Areata; Female; Glucocorticoids; Humans; Injections, Intralesional; Minoxidil; Triamcinolone Acetonide
PubMed: 12643360
DOI: No ID Found -
Biomedicine & Pharmacotherapy =... Jan 2023We reviewed and summarized the latest reports on the characteristics of stem cells and follicular cells that are under development for hair loss treatment. Compared with... (Review)
Review
We reviewed and summarized the latest reports on the characteristics of stem cells and follicular cells that are under development for hair loss treatment. Compared with conventional medicine, cell therapy could be effective in the long term with a single treatment while having mild adverse effects. Adipose-derived stem cells (ASCs) have the advantages of easy access and large isolation amount compared with dermal papilla cells (DPCs) and dermal sheath cup cells (DSCs), and promote hair growth through the paracrine effect. ASCs have a poor potential in hair neogenesis, therefore, methods to enhance trichogenecity of ASCs should be developed. DSCs can be isolated from the peribulbar dermal sheath cup, while having immune tolerance, and hair inductivity. Therefore, DSCs were first developed and finished the phase II clinical trial; however, the hair growth was not satisfactory. Considering that a single injection of DSCs is effective for at least 9 months in the clinical setting, they can be an alternative therapy for hair regeneration. Though DPCs are not yet studied in clinical trials, we should pay attention to DPCs, as hair loss is associated with gradual reduction of DPCs and DP cell numbers fluctuate over the hair cycle. DPCs could make new hair follicles with epidermal cells, and have an immunomodulatory function to enable allogeneic transplantation. In addition, we can expand large quantities of DPCs with hair inductivity using spheroid culture, hypoxia condition, and growth factor supplement. 'Off-the-shelf' DPC therapy could be effective and economical, and therefore promising for hair regeneration.
Topics: Humans; Cells, Cultured; Hair; Hair Follicle; Cell- and Tissue-Based Therapy; Alopecia
PubMed: 36370520
DOI: 10.1016/j.biopha.2022.113988 -
Tidsskrift For Den Norske Laegeforening... Apr 2000
Topics: Alopecia; Attitude of Health Personnel; Empathy; Health Priorities; Humans; Male; Norway; Physician's Role
PubMed: 10863337
DOI: No ID Found -
International Journal of Molecular... Apr 2024Both alopecia areata (AA) and vitiligo are distinct, heterogenous, and complex disease entities, characterized by nonscarring scalp terminal hair loss and skin pigment... (Review)
Review
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.
Topics: Alopecia Areata; Humans; Vitiligo; Animals; Immune Privilege; Cytokines
PubMed: 38673994
DOI: 10.3390/ijms25084409 -
Dermatologic Therapy Jul 2021The coronavirus disease 2019 (COVID-19) has become the most emerging health issue globally. A prompt investigation regarding disease management and treatment is crucial... (Review)
Review
The coronavirus disease 2019 (COVID-19) has become the most emerging health issue globally. A prompt investigation regarding disease management and treatment is crucial for decreasing the burden of the disease. Many explorations and hypotheses have been posed, but the definite treatment has not been determined for COVID-19. Recent studies described a substantial prevalence of COVID-19 and also a higher rate of morbidity and mortality in men afflicted with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The gender-related discordance in COVID-19 infection may be due to hormonal differences, socioeconomic factors, genetic susceptibility, gender-related comorbidities, and habits like alcohol consumption. On the other hand, several studies proposed that androgens could improve the immune system and have a protective role in COVID-19, and decreased levels of androgens might be associated with unsatisfactory outcomes. In the field of dermatology, androgenetic alopecia (AGA) is correlated with a hyperandrogenic state and may be related to COVID-19 severity. Furthermore, recent research has assessed the plausible association of AGA and COVID-19. In this review, we investigate all evidence on AGA and its relationship with COVID-19, including the possible role of androgens in COVID-19 severity and outcomes as well as candidate androgen-related drugs for the treatment of COVID-19.
Topics: Alopecia; Androgens; COVID-19; Genetic Predisposition to Disease; Humans; Male; SARS-CoV-2
PubMed: 34033224
DOI: 10.1111/dth.15004 -
JAMA Dermatology Apr 2023Alopecia areata (AA) is characterized by nonscarring hair loss of the scalp, face, and/or body. Alopecia totalis (AT) and alopecia universalis (AU) involve complete loss...
IMPORTANCE
Alopecia areata (AA) is characterized by nonscarring hair loss of the scalp, face, and/or body. Alopecia totalis (AT) and alopecia universalis (AU) involve complete loss of the scalp and body hair, respectively. The epidemiology of AA in the US remains unclear, having previously been extrapolated from older studies that were limited to specific geographic areas or clinical settings, or from self-reported data.
OBJECTIVE
To estimate the annual prevalence and incidence of AA and AT and/or AU (AT/AU) in the US.
DESIGN, SETTING, AND PARTICIPANTS
This retrospective, population-based cohort study was conducted from January 2016 to December 2019 and included enrollees in the IBM MarketScan Commercial Claims and Encounters and Medicare Supplemental databases and their dependents, with plan enrollment during each study calendar year and the year prior.
EXPOSURES
Prevalent cases were identified by 1 or more claims for AA or AT/AU (International Statistical Classification of Diseases, Tenth Revision, Clinical Modification [ICD-10-CM] codes L63.x, L63.0, L63.1) during each year of interest or the year prior. Incident cases were identified by 1 or more claims for AA or AT/AU during a specific year and no diagnosis the year prior.
MAIN OUTCOMES AND MEASURES
Annual incidence and prevalence rates were calculated and stratified by age, sex, and region. National employer-sponsored insurance population estimates were obtained using population-based weights.
RESULTS
Among eligible patients (2016: n = 18 368 [mean (SD) age, 40.6 (17.9) years; 12 295 women (66.9%)]; 2017: n = 14 372 [mean (SD) age, 39.6 (17.7) years; 9195 women (64.0%)]; 2018: n = 14 231 [mean (SD) age, 38.9 (17.3) years; 8998 women (63.2%)]; 2019: n = 13 455 [mean (SD) age, 39.1 (17.4) years; 8322 women (61.9%)]), AA prevalence increased from 0.199% (95% CI, 0.198%-0.200%) in 2016 to 0.222% (95% CI, 0.221%-0.223%) in 2019. Roughly 5% to 10% of prevalent and incident cases of AA were AT/AU. The prevalence of AT/AU increased from 0.012% (95% CI, 0.012%-0.013%) to 0.019% (95% CI, 0.018%-0.019%) from 2016 to 2019. Incidence of AA per 100 000 person-years ranged from 87.39 (95% CI, 86.84-87.96) in 2017 to 92.90 (95% CI, 92.35-93.45) in 2019. Incidence of AT/AU ranged from 7.09 (95% CI, 6.94-7.25) in 2017 to 8.92 (95% CI, 8.75-9.09) in 2016. Prevalence and incidence of AA and AT/AU were higher among female vs male individuals, adults vs children and adolescents, and in the Northeast vs other regions.
CONCLUSIONS AND RELEVANCE
The results of this cohort study suggest that these recent AA prevalence and incidence estimates could help improve current understanding of the disease burden. Further research is warranted to elucidate subpopulation differences and trends in AA in the broader US population.
Topics: Aged; Adolescent; Humans; Female; Adult; Male; Child; United States; Alopecia Areata; Retrospective Studies; Incidence; Prevalence; Cohort Studies; Medicare; Alopecia
PubMed: 36857069
DOI: 10.1001/jamadermatol.2023.0002 -
The Journal of Investigative... Jun 2003Androgenetic alopecia (AGA), also known in women as female pattern hair loss, is caused by androgens in genetically susceptible women and men. The thinning begins... (Review)
Review
Androgenetic alopecia (AGA), also known in women as female pattern hair loss, is caused by androgens in genetically susceptible women and men. The thinning begins between ages 12 and 40 years, the inheritance pattern is polygenic, and the incidence is the same as in men. In susceptible hair follicles, dihydrotestosterone binds to the androgen receptor, and the hormone-receptor complex activates the genes responsible for the gradual transformation of large terminal follicles to miniaturized follicles. Both young women and young men with AGA have higher levels of 5alpha reductase and androgen receptor in frontal hair follicles compared to occipital follicles. At the same time, young women have much higher levels of cytochrome p-450 aromatase in frontal follicles than men who have minimal aromatase, and women have even higher aromatase levels in occipital follicles. The diagnosis of AGA in women is supported by early age of onset, the pattern of increased thinning over the frontal/parietal scalp with greater density over the occipital scalp, retention of the frontal hairline, and the presence of miniaturized hairs. Most women with AGA have normal menses and pregnancies. Extensive hormonal testing is usually not needed unless symptoms and signs of androgen excess are present such as hirsutism, severe unresponsive cystic acne, virilization, or galactorrhea. Topical minoxidil solution is the only drug available for promoting hair growth in women with AGA. Efficacy has been shown in double-blind studies using hair counts and hair weight.
Topics: Alopecia; Clinical Laboratory Techniques; Controlled Clinical Trials as Topic; Diagnosis, Differential; Female; Humans; Minoxidil
PubMed: 12894991
DOI: 10.1046/j.1523-1747.2003.12168.x -
Acta Dermato-venereologica Aug 2022
Topics: Alopecia; Humans; Hypohidrosis; Nail Diseases; Nails, Malformed; Propylthiouracil
PubMed: 35971830
DOI: 10.2340/actadv.v102.2690