Changes in the sebaceous gland in patients with male pattern hair loss (androgenic alopecia)

Sebaceous gland atrophy due to seborrheic dermatitis in a patient with alopecia: A potential pitfall

Seborrheic dermatitis is an inflammatory condition that usually presents with erythema, scaly greasy papules, and plaques affecting sebaceous gland-rich areas and predominantly involving the face and scalp. The diagnosis of seborrheic dermatitis can often be rendered based on the clinical presentation. However, in certain cases, a biopsy can be useful to distinguish it from clinical mimics such as psoriasis, discoid lupus, and rosacea. Prominent sebaceous gland atrophy without scarring has been well-described as an important and relatively specific clue for psoriatic or drug-induced alopecia. However, sebaceous gland atrophy is not specific to psoriasis and has been demonstrated in seborrheic dermatitis, facial discoid dermatitis, and potentially may occur in other inflammatory dermatoses of the scalp. We report a 23-year-old female patient presenting with non-scarring hair loss and histopathological findings demonstrating mild androgenetic alopecia and changes of seborrheic dermatitis with dramatic sebaceous gland atrophy. The patient had no history or evidence of psoriasis clinically. Our case suggests that in patients with seborrheic dermatitis, sebaceous gland atrophy may complicate the evaluation of alopecia biopsies and should be recognized as a pitfall. Seborrheic dermatitis should be included in the differential diagnosis of alopecia biopsies showing prominent sebaceous gland atrophy.

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.

Antioxidant and 5α-Reductase Inhibitory Activity of Momordica charantia Extract, and Development and Characterization of Microemulsion

Momordica charantia (M. charantia) is rich in flavonoids, which possess a strong antioxidant capacity and may help prevent hair loss. This study aims to develop the microemulsion of M. charantia with antioxidant activity and 5α-reductase (5aR) inhibitory activity. The total phenolic content (TPC), antioxidant activity, and 5aR inhibitory activity of ethanolic and aqueous extracts of the fruit were investigated. The preparation of M. charantia extract-loaded microemulsion (MELM) was optimized and characterized the MELM. The aqueous extract of M. charantia fruit flesh displayed a TPC of 780.75 ± 24.82 mg Gallic acid equivalence/g of extract. ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl), and nitric oxide (NO) radical scavenging activities were observed in all the extracts. About 0.461 ± 0.003 mg finasteride equivalence/g of extract of 5aR inhibitory activity was detected in the aqueous extract of the inner tissue of M. charantia fruit. Based on NO radical scavenging and 5aR inhibitory activity, an aqueous extract of the inner tissue (pericarp with seed) of M. charantia fruit was used to prepare the MELM. The MELM was prepared using a different ratio of tween 80 and ethanol as Smix. The results showed that the 1:1 ratio of tween 80: ethanol produced microemulsion of an optimum size, zeta potential, and polydispersity index. The MELM samples were stored at 5, 30, and 40 °C for 12 weeks, and the stability was assessed. The results revealed that the size, zeta potential, and polydispersity index of the formulated MELM remained unchanged during the investigated time. This study primarily reports the 5aR inhibitory activity of M. charantia extract and the development of microemulsion. The prepared MELM could be further developed into cosmetic or pharmacological preparations to manage hair loss.

Comparison of low-level light therapy and combination therapy of 5% minoxidil in the treatment of female pattern hair loss

This study was conducted in order to compare the safety and efficacy of LLLT, 5% minoxidil, and combination therapy in the treatment of FPHL. A randomized controlled trial was developed to study the effect of LLLT on FPHL using a device called iHelmet®, which is equipped with 200 5mW laser diode source (650 nm) arrays. Ninety Ludwig's types II-III FPHL patients were randomly divided into 3 groups: LLLT group (A), 5% minoxidil group (B), and combination group(C). Hair density, hair diameter, and scalp oil-secretion were detected to evaluate the treatment effect. Significant improvement of hair density and hair diameter was observed in all stages of FPHL after treatment. Oil-secretion of the three groups was decreased after treatment. The effectiveness of reducing oil-secretion in LLLT group and combination group was higher than minoxidil group (P < 0.05). For improving hair diameter and hair density, combination group was better than LLLT and minoxidil groups. No side effects were reported. Our study illustrated that LLLT is a safe and effective treatment for FPHL. Besides, LLLT can significantly improve its efficacy when used in combination with 5% minoxidil.

An updated review of the sebaceous gland and its role in health and diseases Part 2: Pathophysiological clinical disorders of sebaceous glands

Sebaceous glands are sebum-secreting components of pilosebaceous units. In the second of this two-part series, we review the pathologies in which sebaceous glands are primarily and secondarily implicated. They are primarily involved in steatocystoma simplex and multiplex, sebaceous gland hyperplasia, sebaceoma, sebaceous adenoma, sebaceous carcinoma, nevus sebaceus, and folliculosebaceous cystic hamartoma. Sebaceous glands are secondarily involved in acne vulgaris, seborrheic dermatitis, and androgenic alopecia. Steatocystoma multiplex is a benign congenital anomaly presenting as yellow cysts primarily on the upper body. Sebaceous gland hyperplasia is characterized by yellow, telangiectatic papules with a central dell, and it can be treated with topical retinoids or surgical excision. Sebaceoma clinically presents on the head and neck region as a skin-colored nodule and can be distinguished by immunohistochemistry. Stains used in the diagnosis of sebaceous adenoma and carcinoma include epithelial membrane antigen and adipophilin immunoperoxidase. Surgical excision is the preferred treatment for sebaceoma, sebaceous adenoma, and sebaceous carcinoma. Excision is not always indicated for nevus sebaceus. Folliculosebaceous cystic hamartoma is a relatively rare condition exhibiting both epithelial and mesenchymal components. Patients with acne vulgaris commonly present with papules of closed and open comedones displaying hypercornification. Seborrheic dermatitis presents as sharply demarcated yellow or red patches or plaques; antifungal agents, corticosteroids, and combination antifungal/anti-inflammatory therapies are common treatment modalities. As a result of hair follicle miniaturization, females with androgenic alopecia present with diffuse hair thinning, while men tend to present with balding and hairline recession.

Dihydrotestosterone-induced hair regrowth inhibition by activating androgen receptor in C57BL6 mice simulates androgenetic alopecia

Androgenic alopecia (AGA), also known as male pattern baldness, is one of the most common hair loss diseases worldwide. The main treatments of AGA include hair transplant surgery, oral medicines, and LDL laser irradiation, although no treatment to date can fully cure this disease. Animal models play important roles in the exploration of potential mechanisms of disease development and in assessing novel treatments. The present study describes androgen receptor (AR) in C57BL/6 mouse hair follicles that can be activated by dihydrotestosterone (DHT) and translocate to the nucleus. This led to the design of a mouse model of androgen-induced AGA in vivo and in vitro. DHT was found to induce early hair regression, hair miniaturization, hair density loss, and changes in hair morphology in male C57BL/6 mice. These effects of DHT could be partly reversed by the AR antagonist bicalutamide. DHT had similar effects in an ex vivo model of hair loss. Evaluation of histology, organ culture, and protein expression could explain the mechanism by which DHT delayed hair regrowth.

Efficacy of Platelet-rich Plasma for Treating Androgenic Alopecia of Varying Grades

BACKGROUND AND OBJECTIVES

Platelet-rich plasma (PRP) has received growing attention as a valuable therapeutic tool in androgenetic alopecia (AGA). However, knowledge regarding specific effectiveness and satisfaction of PRP for different grades of AGA in male pattern hair loss (MPHL) and female pattern hair loss (FPHL) is missing. This study aims to ascertain and compare the efficacy and safety of PRP treatment for different grades of AGA in males and females over 6 months.

METHODS

In this study, 51 MPHL patients with Norwood-Hamilton stage II-V and 42 FPHL patients with Ludwig stage I to III were enrolled for 6 monthly sessions of PRP injections. A longitudinal analysis was used to compare the hair density, thickness, and hair pull test over 6 months for MPHL and FPHL through generalized estimating equation (GEE) models. Phototrichograms of scalp inflammation and oil secretion, global photographs and overall patient satisfaction were also assessed.

RESULTS

Consequently, improvement of hair density, hair thickness, hair pull test, the level of scalp inflammation and oil secretion were observed with statistical significance in all stages for both MPHL and FPHL at 6 months. Noteworthy, lower level of alopecia (Grade II, III in MPHL and Grade I in FPHL) had better response to PRP, and also had a better tendency of increment of hair growth than that of high-grade patients with prolonged treatment.

CONCLUSIONS

PRP injections, as an efficacious and reliable therapy, can be recommended for Grade II and Grade III in MPHL and Grade I in FPHL.

Development of new 3D human ex vivo models to study sebaceous gland lipid metabolism and modulations

OBJECTIVES

Sebaceous glands maintain skin homeostasis by producing sebum. Low production can induce hair loss and fragile skin. Overproduction provokes seborrhoea and may lead to acne and inflammatory events. To better study sebaceous gland maintenance, sebocyte maturation, lipid production and ageing or inflammatory processes, we developed innovative 3D ex vivo models for human sebaceous glands.

MATERIALS AND METHODS

Culture conditions and analytical methods optimized on sebocyte monolayers were validated on extracted sebaceous glands and allowed the development of two 3D models: (a) "air-liquid" interface and (b) human fibronectin-coated "sandwich" method. Lipid production was assessed with microscopy, fluorometry or flow cytometry analysis after Nile Red staining. Specific lipids (particularly squalene and peroxidized squalene) were measured by Gas or liquid Chromatography and Mass spectrometry.

RESULTS

This study allowed us to select appropriate conditions and design Seb4Gln culture medium inducing sebocyte proliferation and neutral lipid production. The "air-liquid" model was appropriate to induce sebocyte isolation. The "sandwich" model enabled sebaceous gland maintenance up to 42 days. A treatment with Insulin Growth Factor-1 allowed validation of the model as we succeeded in mimicking dynamic lipid overproduction.

CONCLUSION

Functional sebocyte maturation and physiological maintenance were preserved up to 6 weeks in our models. Associated with functional assays, they provide a powerful platform to mimic physiological skin lipid metabolism and to screen for active ingredients modulating sebum production.

Feature characterization of scarring and non-scarring types of alopecia by multiphoton microscopy

OBJECTIVES

Non-invasive visualization of hair follicles is important for proper diagnosis and management of alopecia; however, histological assessment remains the gold standard. Laser imaging technologies have made possible noninvasive in vivo evaluation of skin and hair follicle. The aim of this study was to evaluate the ability of multiphoton microscopy (MPM) to non-invasively identify morphological features that can distinguish scarring from non-scarring alopecia.

METHODS

MPM images were obtained from areas on the scalp affected by alopecia. Investigators blinded to the diagnosis analyzed hair follicle and shaft sizes. Patients were recruited and imaged at the UC Irvine Health Medical Center and the University of California, Irvine Beckman Laser Institute. Patients with androgenetic alopecia (AGA) and alopecia areata (AA), and scarring alopecia, in particular frontal fibrosing alopecia (FFA) were recruited and imaged from July 2016 to July 2017.

RESULTS

We imaged 5 normal scalp subjects and 12 patients affected by non-scarring (7 subjects) and scarring (5 subjects) alopecia. In normal and non-scarring alopecia patients, MPM identified presence of sebaceous glands associated with hair follicles. MPM images of scarring alopecia were characterized by the presence of inflammatory cells surrounding hair follicles. Measurements of hair follicle diameter sizes were found to be significantly smaller in scarring alopecia patients compared to normal (P < 0.001) and compared to non-scarring alopecia patients (P = 0.046); non-scarring hair follicles were also significantly smaller than normal hair follicles (P = 0.043).

CONCLUSIONS

This study shows that MPM imaging can non-invasively identify morphological features that distinguish scarring from non-scarring alopecia. Further studies are needed to validate this technique and evaluate its potential to be used as an aid for guiding treatment. Lasers Surg. Med. 51:95-103, 2019. © 2018 Wiley Periodicals, Inc.

The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders

The skin is the largest organ of the body and has a complex and very active structure that contributes to homeostasis and provides the first line defense against injury and infection. In the past few years it has become evident that the endocannabinoid system (ECS) plays a relevant role in healthy and diseased skin. Specifically, we review how the dysregulation of ECS has been associated to dermatological disorders such as atopic dermatitis, psoriasis, scleroderma and skin cancer. Therefore, the druggability of the ECS could open new research avenues for the treatment of the pathologies mentioned. Numerous studies have reported that phytocannabinoids and their biological analogues modulate a complex network pharmacology involved in the modulation of ECS, focusing on classical cannabinoid receptors, transient receptor potential channels (TRPs), and peroxisome proliferator-activated receptors (PPARs). The combined targeting of several end-points seems critical to provide better chances of therapeutically success, in sharp contrast to the one-disease-one-target dogma that permeates current drug discovery campaigns.

Sebo-pharmacokinetics: a proposed percutaneous sebum egression method

BACKGROUND/AIMS

The sebaceous gland is widely believed a critical factor in the pathogenesis of acne vulgaris. Although extensive studies document the ability of oral and topical treatments to improve acne, little is known about the quantification and mechanism of drug delivery via the sebaceous gland. A percutaneous egression method presents a way to study how drugs reaching the bloodstream can enter the skin.

METHODS

A literature search was performed across databases (PubMed, Embase, and Google Scholar) and the University of California, San Francisco (UCSF) textbook library with relevant search terms.

RESULTS

This search failed to reveal data on sebo-pharmacokinetics (PK); however, many articles center on pharmacodynamics (PD) - i.e. functional improvement instigated by oral or topical treatments. Experiments on humans and hamsters - representative sebaceous gland models - demonstrate indirect PD measures of sebaceous gland function.

DISCUSSION

Here, we summarize the current available data on drug delivery via the sebaceous gland and suggest a practical method to directly document sebo-PK in man and animal.

A hypothetical pathogenesis model for androgenic alopecia: clarifying the dihydrotestosterone paradox and rate-limiting recovery factors

Androgenic alopecia, also known as pattern hair loss, is a chronic progressive condition that affects 80% of men and 50% of women throughout a lifetime. But despite its prevalence and extensive study, a coherent pathology model describing androgenic alopecia's precursors, biological step-processes, and physiological responses does not yet exist. While consensus is that androgenic alopecia is genetic and androgen-mediated by dihydrotestosterone, questions remain regarding dihydrotestosterone's exact role in androgenic alopecia onset. What causes dihydrotestosterone to increase in androgenic alopecia-prone tissues? By which mechanisms does dihydrotestosterone miniaturize androgenic alopecia-prone hair follicles? Why is dihydrotestosterone also associated with hair growth in secondary body and facial hair? Why does castration (which decreases androgen production by 95%) stop pattern hair loss, but not fully reverse it? Is there a relationship between dihydrotestosterone and tissue remodeling observed alongside androgenic alopecia onset? We review evidence supporting and challenging dihydrotestosterone's causal relationship with androgenic alopecia, then propose an evidence-based pathogenesis model that attempts to answer the above questions, account for additionally-suspected androgenic alopecia mediators, identify rate-limiting recovery factors, and elucidate better treatment targets. The hypothesis argues that: (1) chronic scalp tension transmitted from the galea aponeurotica induces an inflammatory response in androgenic alopecia-prone tissues; (2) dihydrotestosterone increases in androgenic alopecia-prone tissues as part of this inflammatory response; and (3) dihydrotestosterone does not directly miniaturize hair follicles. Rather, dihydrotestosterone is a co-mediator of tissue dermal sheath thickening, perifollicular fibrosis, and calcification - three chronic, progressive conditions concomitant with androgenic alopecia progression. These conditions remodel androgenic alopecia-prone tissues - restricting follicle growth space, oxygen, and nutrient supply - leading to the slow, persistent hair follicle miniaturization characterized in androgenic alopecia. If true, this hypothetical model explains the mechanisms by which dihydrotestosterone miniaturizes androgenic alopecia-prone hair follicles, describes a rationale for androgenic alopecia progression and patterning, makes sense of dihydrotestosterone's paradoxical role in hair loss and hair growth, and identifies targets to further improve androgenic alopecia recovery rates: fibrosis, calcification, and chronic scalp tension.

Hairless controls hair fate decision via Wnt/β-catenin signaling

The hairless (Hr) gene plays a central role in the hair cycle, considering that mutations in the gene result in hair loss with the exception of a few vibrissae after the first hair growth cycle in both mice and humans. This study examinedthe uncommon phenotype and using microarray analyses and functional studies, we found that β-catenin was mediated by Hr. Progenitor keratinocytes from the bulge region differentiate into both epidermis and sebaceous glands, and fail to adopt the hair keratinocytes fate in the mutant scalp, due to the decreased Wnt/β-catenin signaling in the absence of the hairless protein. This may be attributed to the dysfunction of normal epithelial-mesenchymal interactions in the hair follicle (HF).

Marked Reduction of the Number and Individual Volume of Sebaceous Glands in Psoriatic Lesions

BACKGROUND

Psoriasis is a chronic inflammatory skin disease characterized by plaques with inflammation, infiltration, hyper-/parakeratosis and desquamation. Microscopic findings in previous studies have revealed some degree of atrophy of the sebaceous glands in patients with psoriasis vulgaris and psoriatic alopecia.

OBJECTIVE

The aim of this study was to investigate possible changes of the sebaceous glands in patients with psoriatic plaques and especially psoriatic alopecia.

METHODS

Histological and stereological analyses were performed in skin specimens from involved and healthy-looking skin of 14 patients with psoriasis. Stereology detects and quantifies 3-dimensional structures ex vivo. Furthermore, the differentiation process of sebocytes of another 14 psoriatic patients was examined by immunohistochemistry of involved and uninvolved skin specimens.

RESULTS

A significant reduction of the number of sebaceous glands as well as of the volume of individual sebaceous glands was assessed in the lesional compared to the nonlesional psoriatic skin. Moreover, it was likely that sebocytes in psoriatic lesions may not differentiate properly.

CONCLUSION

These findings indicate that the sebaceous gland may be a player and not an innocent bystander in the development of psoriatic lesions and especially of psoriatic alopecia.