The physiological and pharmacological roles of prostaglandins in hair growth

Hair loss is a common status found among people of all ages. Since the role of hair is much more related to culture and individual identity, hair loss can have a great influence on well-being and quality of life. It is a disorder that is observed in only scalp patients with androgenetic alopecia (AGA) or alopecia areata caused by stress or immune response abnormalities. Food and Drug Administration (FDA)-approved therapeutic medicines such as finasteride, and minoxidil improve hair loss temporarily, but when they stop, they have a limitation in that hair loss occurs again. As an alternative strategy for improving hair growth, many studies reported that there is a relationship between the expression levels of prostaglandins (PGs) and hair growth. Four major PGs such as prostaglandin D2 (PGD₂), prostaglandin I2 (PGI₂), prostaglandin E2 (PGE₂), and prostaglandin F2 alpha (PGF₂α) are spatiotemporally expressed in hair follicles and are implicated in hair loss. This review investigated the physiological roles and pharmacological interventions of the PGs in the pathogenesis of hair loss and provided these novel insights for clinical therapeutics for patients suffering from alopecia.

Conflicting Reports Regarding the Histopathological Features of Androgenic Alopecia: Are Biopsy Location, Hair Diameter Diversity, and Relative Hair Follicle Miniaturization Partly to Blame?

Despite decades of study, debate persists over the role of inflammation, fibrosis, and prostaglandins in the histopathology of androgenic alopecia (AGA). This brief review proposes that inconsistent findings across histological studies are a consequence of three inadequately controlled variables: 1) biopsy location, 2) hair diameter diversity (HDD), and 3) relative hair follicle miniaturization (HFM) within and across subjects. We suggest new methodological considerations to improve AGA histopathological research, as well as a novel classification system to quantify HFM by its stages. Finally, we hypothesize a dynamic relationship between inflammation, fibrosis, and prostaglandin activity dependent on relative HFM.

Systemic dexpanthenol as a novel treatment for female pattern hair loss

BACKGROUND

There are only a few drugs that have been used for the treatment of female pattern hair loss (FPHL).

AIMS

Through use of the Dermatologic Life Quality Index (DLQI) and a modified hair growth questionnaire, we aimed to evaluate the effect of dexpanthenol (DXP) as a new option for FPHL.

METHODS

Women who received 500 mg intramuscular DXP weekly for FPHL were included in this study. They were evaluated in terms of DLQI and laboratory characteristics, before and after DXP treatment, and were examined with a modified hair growth questionnaire.

RESULTS

Overall satisfaction with the appearance of the hair was described by the patients as 57.1% " I am satisfied," 28.6% "I am very satisfied," and 14.3% "I am neutral (neither satisfied nor dissatisfied)." There was a statistical difference between the mean DLQI scores before and after DXP treatment (P < .001). No statistical difference was found in the laboratory characteristics of the patients before and after DXP treatment (P > 0.05). No side effect was reported during DXP treatment.

CONCLUSION

Dexpanthenol is a safe and novel drug that may increase the quality of life in patients with FPHL.

The prostaglandin synthases, COX-2 and L-PGDS, mediate prostate hyperplasia induced by low-dose bisphenol A

This study aimed to identify prostaglandin synthases (PGS) that mediate bisphenol A (BPA)-induced prostatic hyperplasia and explore their underlying mechanisms. In an in vivo study, male adult Sprague–Dawley rats were treated with different concentrations of BPA (10, 30, 90, or 270 μg/kg, i.g., daily), or with vehicle for 4 weeks. Results revealed that low-dose BPA induced prostatic hyperplasia with increased PCNA/TUNEL ratio. It significantly upregulated the expression of cyclooxygenase-2 (COX-2) and NF-κB in the dorsolateral prostate (P < 0.05) and the expression of lipocalin-type prostaglandin D synthase (L-PGDS) in ventral prostate (P < 0.05). The level of estradiol (E₂)/testosterone (T) and expression of androgen receptor (AR) and estrogen receptor α (ERα) were also altered. In vitro studies showed that low-dose BPA (0.1–10 nM) promoted the proliferation of human prostate fibroblasts and epithelial cells, and significantly upregulated the expression of COX-2 and L-PGDS in the cells. The two types of cell proliferation induced by BPA were inhibited by COX-2 inhibitor (NS398) and L-PGDS inhibitor (AT56), with increased apoptosis level. These findings suggested that COX-2 and L-PGDS could mediate low-dose BPA-induced prostatic hyperplasia through pathways involved in cell proliferation and apoptosis, which might be related to the functions of ERα and AR. The role of COX-2/NF-κB pathway in dorsolateral prostate requires further research.

Pharmacological therapeutics in androgenetic alopecia

Androgenetic alopecia (AGA) is the most common type of hair loss and affects both men and women. Male pattern hair loss shows characteristic frontal recession and vertex baldness, whereas female pattern hair loss produces diffuse alopecia over the mid-frontal scalp. AGA is mediated by increased androgen susceptibility in affected scalp hairs. 5α-Reductase converts testosterone into dihydrotestosterone, a potent androgen, in the scalp. Both androgen receptors and 5α-reductase have higher expression levels in the balding scalp than in non-affected regions. Increased androgen susceptibility induces hair follicle miniaturization, which leads to the progressive loss of thicker terminal hairs in the balding scalp. Currently, topical minoxidil and oral 5α-reductase inhibitors, such as finasteride and dutasteride, are approved options for the pharmacological treatment of AGA. Topical minoxidil remains the mainstay of therapy for mild to moderate AGA in both men and women. The daily intake of 1-mg finasteride or 0.5-mg dutasteride shows better efficacy than topical minoxidil in regard to hair regrowth in male AGA. Anti-androgens can be used in female AGA wit clinical and biochemical evidence of hyperandrogenism. Patients may be overwhelmed and confused by the variety of treatment options for AGA management, including over-the-count drugs with low evidence quality. Therefore, physicians must be aware of the current guidelines for the management of AGA based on evidence-based approaches to select better options for patients.