Detection of Tumor Necrosis Factor-alpha in Nonlesional Tissues of Alopecia Areata Patients: A Prove for a Systemic Disease

Immune niches for hair follicle development and homeostasis

The hair follicle is a dynamic mini-organ that has specialized cycles and architectures with diverse cell types to form hairs. Previous studies for several decades have investigated morphogenesis and signaling pathways during embryonic development and adult hair cycles in both mouse and human skin. In particular, hair follicle stem cells and mesenchymal niches received major attention as key players, and their roles and interactions were heavily revealed. Although resident and circulating immune cells affect cellular function and interactions in the skin, research on immune cells has mainly received attention on diseases rather than development or homeostasis. Recently, many studies have suggested the functional roles of diverse immune cells as a niche for hair follicles. Here, we will review recent findings about immune niches for hair follicles and provide insight into mechanisms of hair growth and diseases.

Adiponectin serum levels and ADIPOQ (rs2241766) polymorphism in alopecia areata Egyptian patients

BACKGROUND

Alopecia Areata (AA) is an acquired autoimmune form of non-scarring hair loss. Adiponectin and its gene polymorphism were related to many autoimmune disorders.

OBJECTIVE

Assessment of adiponectin serum levels and adiponectin gene (ADIPOQ) (rs2241766) Single Nucleoid Polymorphism (SNP) in AA patients and correlating the results with the disease severity in those patients.

METHODS

This study included 75 AA patients and 75 age and gender-matched healthy subjects (controls). The severity of Alopecia Tool (SALT) score assessment to evaluate AA severity was done. Adiponectin serum levels by ELISA and ADIPOQ (rs2241766) SNP using PCR were performed.

RESULTS

Adiponectin serum levels were significantly lower in AA patients than controls (p = 0.001). ADIPOQ (rs2241766) TG genotype and G allele were significantly predominant in AA patients increasing its risk by 5 and 4 folds (OR = 5.17, p = 0.001), (OR = 3.82, p = 0.001) respectively. Serum adiponectin levels were negatively correlated with SALT score (r = -0.435, p = 0.001) and associated with alopecia totalis (p = 0.016). ADIPOQ (rs2241766) TG genotype was significantly associated with low serum adiponectin levels and higher SALT score (p = 0.001).

STUDY LIMITATIONS

The small sample size.

CONCLUSIONS

ADIPOQ (rs2241766) gene polymorphism (TG genotype and G allele) may modulate AA risk and contribute to the development of AA in Egyptian populations. Decreased circulating adiponectin levels may have a dynamic role in AA etiopathogenesis. Adiponectin serum concentration can be considered a severity marker of hair loss in AA.

Psychological Stress-Induced Pathogenesis of Alopecia Areata: Autoimmune and Apoptotic Pathways

Alopecia areata (AA) is an autoimmune dermatological disease with multifactorial etiology and is characterized by reversible hair loss in patches. AA may be closely related to emotional stress and influenced by psychological factors as part of its pathophysiology; however, its etiology remains predominantly unknown. This review aimed to elucidate the association between AA occurrence and the neuropeptide substance P (SP) and corticotropin-releasing hormone (CRH), which are secreted during emotional stress, and have been understood to initiate and advance the etiopathogenesis of AA. Therefore, this review aimed to explain how SP and CRH initiate and contribute to the etiopathogenesis of AA. To assess the etiopathogenesis of AA, we conducted a literature search on PubMed and ClinicalTrials.gov. Overall, several authors described interactions between the hair follicles (HFs) and the stress-associated signaling substances, including SP and CRH, in the etiology of AA; this was attributed to the understanding in that AA can occur without the loss of HFs, similar to that observed in hereditary hair loss with age. Most studies demonstrated that the collapse of "immune privilege" plays a crucial role in the development and exacerbation of the AA; nonetheless, a few studies indicated that substances unrelated to autoimmunity may also cause apoptosis in keratocytes, leading to the development of AA. We investigated both the autoimmune and apoptotic pathways within the etiology of AA and assessed the potential interactions between the key substances of both pathways to evaluate potential therapeutic targets for the treatment of AA. Clinical trials of marketed/unreviewed intervention drugs for AA were also reviewed to determine their corresponding target pathways.

Interleukin-15 and Tumor Necrosis Factor-α in Iraqi Patients with Alopecia Areata

Background

Alopecia areata (AA) is a common form of noncicatricial hair loss of unknown cause, affecting 0.1-0.2% of the general population. Most evidence supports the hypothesis that it is disease of the hair follicle of autoimmune nature mediated by T-cells, with important cytokine role. Objective of the Study. The objective of this study is to study the association and changes in serum levels of interleukin-15 (IL-15) and tumor necrosis factor-α (TNF-α) in patients with AA in relation to the type, activity, and disease duration. Patients and Methods. Thirty-eight patients with AA and 22 individuals without the disease as controls were enrolled in this case-controlled study conducted in the Department of Dermatology in the Al-Kindy Teaching Hospital and Baghdad Medical City, Iraq, during a period from the 1st of April 2021 to the 1st of December 2021. Serum concentrations of IL-15 and TNF-α assessed using the enzyme-linked immunosorbent assay.

Results

The mean serum concentration values for IL-15 and TNF-α were higher significantly in patients with AA than in controls (2.35 versus 0.35 pg/mL and 50.11 versus 20.92 pg/mL, respectively). IL-15 and TNF-α showed no statistically significant differences in level in terms of the type, duration, and activity of the disease, but TNF-α significantly higher in those with totalis-type than in other types.

Conclusion

Both IL-15 and TNF-α are markers for alopecia areata. The level for these biomarkers was not affected by duration or disease activity, but it was affected by the type of disease, as the concentrations of IL-15 and TNF-α were higher in patient with Alopecia totalis than in other types of Alopecia.

Consumption of fish oil high-fat diet induces murine hair loss via epidermal fatty acid binding protein in skin macrophages

Fats are essential in healthy diets, but how dietary fats affect immune cell function and overall health is not well understood. Mimicking human high-fat diets (HFDs), which are rich in different fatty acid (FA) components, we fed mice various HFDs from different fat sources, including fish oil and cocoa butter. Mice consuming the fish oil HFD exhibit a hair-loss phenotype. Further studies show that omega-3 (n-3) FAs in fish oil promote atypical infiltration of CD207- (langerin-) myeloid macrophages in skin dermis, which induce hair loss through elevated TNF-α signaling. Mechanistically, epidermal fatty acid binding protein (E-FABP) is demonstrated to play an essential role in inducing TNF-α-mediated hair loss by activating the n-3 FA/ROS/IL-36 signaling pathway in dermal resident macrophages. Absence of E-FABP abrogates fish oil HFD-induced murine hair loss. Altogether, these findings support a role for E-FABP as a lipid sensor mediating n-3 FA-regulated macrophage function and skin health.

COVID-19 Infection: Impact on Hair

With a practice dedicated to hair restoration and hair loss management, the authors have seen a large number of patients presenting with increased hair fall in the last 18 months. Hair fall after a stressfull event such as infections with febrile episodes is known. However, the latent period between the infective episode and hair fall has been shorter after COVID-19 infection than before. This review attempts to look at various pathways responsible for hair fall and if this differs from the conventional hair fall seen after any infection. It also tries to understand if the infection with the SARS-CoV-2 virus has a direct impact on the hair follicle leading to hair fall.

Current insight into the functions of microRNAs in common human hair loss disorders: a mini review

Alopecia areata (AA) and Androgenic alopecia (AGA) are the most common multifactorial hair loss disorders that have a serious psychological impact on the affected individuals, while frontal fibrosing alopecia (FFA) is comparatively less common. However, due to the unknown etiology and the effect of many adverse factors, the prognosis of these conditions is challenging to predict. Moreover, no approved therapy has been available to date to prevent or treat these disorders. MicroRNAs (miRNAs) are a group of evolutionary conserved small non-coding RNA molecules with significant roles in the posttranscriptional gene regulation either through mRNA degradation or translational repression. A number of biological processes are controlled by these molecules, including cell growth and differentiation, proliferation, inflammation, immune responses, and apoptosis. Recently, a handful of studies have demonstrated the impact of miRNAs on common hair loss-related disorders; however, the exhaustive molecular mechanisms are still unclear. In this review, we discussed the functional implications of miRNAs in common hair loss-related disorders and addressed their efficacy to be used for theranostic purposes shortly.

Immunology of alopecia areata

Alopecia areata is a condition that affects hair follicles and leads to hair loss ranging from small well-defined patches to complete loss of all body hair. Despite its high incidence, the pathobiology is not fully understood, and no single concept could be universally accepted.

Alopecia areata is mostly considered to be an autoimmune disease, in which the collapse of hair follicle immune privilege plays a key role. Higher incidence rate in the female population and increased overall risk of other autoimmune disorders militate in favor of autoimmune hypothesis. Antibodies against multiple components of hair follicles almost exclusively attack in anagen phase, where melanogenesis takes place. It suggests involvement of melanogenesis-associated autoantigens as a target epitope.

Some investigators believed that alopecia areata is not a truly autoimmune disease but is only ‘consistent with’ autoimmune mechanisms. High frequency of a positive family history up to 42% may reflects the contribution of heredity factors. In addition, no specific target autoantigen has been identified so far, and autoantibodies to hair follicle-associated antigens are detectable in normal individuals.

Alteration of serum and tissue tumor necrosis factor alpha levels: A possible mechanism of action of oral pulse steroids in the treatment of alopecia areata

BACKGROUND

Alopecia areata (AA) is a multifactorial disease in which tumor necrosis factor alpha (TNF-α) plays an important role.

OBJECTIVE

To study the effect of oral pulse steroids on both serum and tissue levels of TNF-α in AA patients.

METHODS

Skin biopsies and serum samples were collected from 20 patients with patchy AA before and after treatment (oral prednisolone for two consecutive days every week for 3 months) for determination of the levels of TNF-α levels using ELISA technique.

RESULTS

Both serum and tissue levels of TNF-α in AA patients were significantly higher than in controls before (P < 0.001) as well as after treatment (P = 0.0169 and P = 0.3051), respectively. The duration of disease negatively correlated with tissue TNF-α before treatment (P < 0.0001). Serum and tissue levels of TNF-α dropped significantly after treatment (P < 0.0001). The percentage of reduction of both tissue and serum TNF-α levels correlated positively with the percentage of clinical improvement (r = 0.682, P = 0.0009; r = 0.567, P = 0.009, respectively).

CONCLUSION

TNF-α plays an important role in the evolution of AA lesions, and alteration in both serum and tissue levels of TNF-α could be considered one of the important mechanisms of action of systemic oral pulse steroids in the treatment of AA.