Vol 99, No 3 (2023)

The aromatic hydrocarbon receptor (AhR) is a cytoplasmic receptor and transcription factor that regulates a wide range of biological and toxicological effects by binding to specific ligands. Among the effects there is detoxification of xenobiotics, maintenance of tissue homeostasis, regulation of the immune response. The structure and functions of AhR are described in the review. The mechanisms of skin homeostasis with the participation of the aromatic hydrocarbon receptor such as the effect on oxidative reactions and participation in maintaining the barrier function of the epidermis are demonstrated in details. The role of AhR in the pathogenesis of atopic dermatitis is discussed. The participation of AhR in the implementation of immune mechanisms of this disease as well as in the regulation of the production of key proteins of the skin barrier is shown. The data on the therapeutic value of its pharmacological modulation including the results of clinical studies of the topical ligand AhR Tapinarof are presented. The role of the aromatic hydrocarbon receptor in the realization of the effect of phototherapy of atopic dermatitis is demonstrated.

Background. The initial stages of androgenetic alopecia in men are characterized by a variety of clinical manifestation in the parietal or occipital scalp regions. However, the differences in the pathogenesis of hair loss patterns are not well understood, selective treatment has not been developed.

Aims. Trichological characteristics of patients with initial stages of androgenetic alopecia with identification of genetic and non-genetic factors that determine the hair loss in the different scalp regions, and their response to conservative therapy.

Materials and methods: Trichograms were photodocumented using an AramoSG microcamera (Republic of Korea). The genetic factor was analyzed by mini-sequencing of single nucleotide polymorphisms rs929626, rs5919324, rs1998076, rs12565727, rs756853. The non-genetic factors study included hormonal status (total and free testosterone, dihydrotestosterone, 17OH-progesterone, dehydroepiandrostenone, SHBG) and blood content of trace elements (Mg, Ca, Zn, Cu, Se, Fe) and vitamins (B12, D, E, folic acid). Conservative treatment was topical application of a minoxidil 5% (twice-a-day, 4 months) and a micronutrient deficiencies personalized correction.

Results. The study included 47 man with initial stages of androgenetic alopecia. Their trichological examination showed two patterns, consisting a predominant decrease in the hair density and diameter in the parietal and occipital scalp regions, which were subgroups formation criteria. An intergroup comparison revealed similar genetic risk, while hormonal parameters (increased dihydrotestosterone levels, a decrease in free testosterone) characterized the subgroup with parietal hair loss pattern. Also, a multiple deficiency of Zn, Cu, Se and vitamins B12, D, folic acid was detected in all patients. Subsequent conservative treatment had a positive effect in patients with parietal hair loss pattern, while in patients with occipital pattern no significant response was observed.

Conclusions. The study develops ideas about differences between androgen-dependent parietal and androgen-independent occipital hair loss patterns in the initial stages of androgenetic alopecia, which requires different approaches to their conservative therapy.

Background. Neisseria gonorrhoeae can rapidly develop resistance to antimicrobial agents due to innate mechanisms for the acquisition of antimicrobial resistance genes. Because of the rapid formation of resistance mechanisms of N. gonorrhoeae to the antimicrobial agents used in gonococcal therapy, the risk of incurable forms of the disease is high. The purpose of the study is to to summarize the results of RU-GASP over a 16-year period and assess the trends of N. gonorrhoeae resistance to antimicrobials used in the regimens of antibiotic therapy of gonococcal infection in Russia.

Materials and methods. Study Objective. The study included 5356 isolates of N. gonorrhoeae received from January 2005 to December 2021 in State Scientific Center of Dermatovenerology and Cosmetology, Moscow of the Ministry of Health of Russia under the RU-GASP program from specialized medical organizations of dermatovenerological profile of 37 subjects of the Russian Federation. Primary identification of N. gonorrhoeae was performed using bacterioscopic and bacteriological methods. The cultures identified as N. gonorrhoeae were frozen in a cryogenic medium and transported to SSCDC. Received cultures were verified by biochemical criteria on a VITEK 2 Compact analyzer. For cultures identified as N. gonorrhoeae with less than 99% probability, a time-of-flight ionization mass spectrometer MALDI Microflex (Bruker Daltonics GmbH, Germany) was used for mass spectrometric analysis.

Antimicrobial susceptibility testing. Sensitivity testing of N. gonorrhoeae to six antimicrobials — penicillin, spectinomycin, ceftriaxone, tetracycline, azithromycin and ciprofloxacin was performed by serial dilution in agar with determination of minimum suppressive concentrations (MSC, mg/L). N. gonorrhoeae sensitivity to antibacterial agents was evaluated according to EUCAST criteria (The European Committee on Antimicrobial Susceptibility Testing, 2022, http://www.eucast.org).

Results. The study showed the absence of significant changes in the ratio of sensitive and resistant to the action of antimicrobial drugs strains of N. gonorrhoeae that is a consequence of the effectiveness of the RU-GASP program, which allowed to exclude in time from therapeutic use the drugs for which a high proportion of the identified resistant strains was observed.

Conclusion. Analysis of RU-GASP results over a 16-year period confirms the use of third-generation cephalosporins (Ceftriaxone, Cefixime) as the drugs of choice for therapy of gonococcal infection, and the aminocyclic antibiotic spectinomycin as an alternative drug. The continued evolution of the molecular mechanisms of antibiotic resistance of N. gonorrhoeae dictates the need to continue the RU-GASP program.

Patients with acne often develop neuropsychiatric disorders of varying severity, correlating, as a rule, with the severity of dermatosis. Isotretinoin is the most commonly used drug for the treatment of moderate acne. Due to the fact that in a number of studies isotretinoin was considered as a trigger for the development of various neuropsychiatric disorders, numerous studies were conducted to prove this possibility or to refute it. An analysis of the literature showed that, according to the vast majority of studies, isotretinoin does not lead to neuropsychiatric disorders. However, given the opposite opinion of some authors, it is advisable to actively identify, including in the anamnesis, any psycho-emotional disorders, and monitor them during therapy. In these cases, it is indicated to start treatment with small doses (recommendations have not been developed).

Rosacea is a chronic inflammatory disease of the skin mainly of the central facial region, having gender and age correlations. Currently, more and more data is accumulating on the analysis of rosacea phenotypes, scientific discussions are underway on the feasibility of switching from subtype classification to phenotypic classification to justify individualized approaches to therapy. The phenotypic classification is based on the manifestations of rosacea and distinguishes diagnostic signs from the main and secondary symptoms. Thus, phymatous changes and persistent central facial erythema are the only diagnostic signs (criteria) of rosacea, and erythema, telangiectasia and inflammatory papules/pustules are the main symptoms and only in combination can indicate the diagnosis of rosacea. Secondary signs of rosacea are hot flashes, burning, pain, swelling and a feeling of dryness. The symptoms of rosacea are based on various pathophysiological mechanisms, so therapy in most cases will consist of a combination of topical agents with systemic drugs or physiotherapy. The article presents a clinical case of rosacea based on a phenotypic approach to therapy.