Acne: comparing hormonal approaches to antibiotics and isotretinoin

Effectiveness of the repurposed drug isotretinoin in an experimental murine model of Chagas disease

Benznidazole and nifurtimox are the drugs currently used for the treatment of Chagas disease, however its side effects may affect patient adherence. In the search for new alternative therapies, we previously identified isotretinoin (ISO), an FDA-approved drug widely used for the treatment of severe acne through a drug repurposing strategy. ISO shows a strong activity against Trypanosoma cruzi parasites in the nanomolar range, and its mechanism of action is through the inhibition of T. cruzi polyamine and amino acid transporters from the Amino Acid/Auxin Permeases (AAAP) family. In this work, a murine model of chronic Chagas disease (C57BL/6 J mice), intraperitoneally infected with T. cruzi Nicaragua isolate (DTU TcI), were treated with different oral administrations of ISO: daily doses of 5 mg/kg/day for 30 days and weekly doses of 10 mg/kg during 13 weeks. The efficacy of the treatments was evaluated by monitoring blood parasitemia by qPCR, anti-T. cruzi antibodies by ELISA, and cardiac abnormalities by electrocardiography. No parasites were detected in blood after any of the ISO treatments. The electrocardiographic study of the untreated chronic mice showed a significant decrease in heart rate, while in the treated mice this negative chronotropic effect was not observed. Atrioventricular nodal conduction time in untreated mice was significantly longer than in treated animals. Mice treated even with ISO 10 mg/kg dose every 7 days, showed a significant reduction in anti-T. cruzi IgG levels. In conclusion, the intermittent administration of ISO 10 mg/kg would improve myocardial compromise during the chronic stage.

Trypanocidal Effect of Isotretinoin through the Inhibition of Polyamine and Amino Acid Transporters in Trypanosoma cruzi

Polyamines are essential compounds to all living organisms and in the specific case of Trypanosoma cruzi, the causative agent of Chagas disease, they are exclusively obtained through transport processes since this parasite is auxotrophic for polyamines. Previous works reported that retinol acetate inhibits Leishmania growth and decreases its intracellular polyamine concentration. The present work describes a combined strategy of drug repositioning by virtual screening followed by in vitro assays to find drugs able to inhibit TcPAT12, the only polyamine transporter described in T. cruzi. After a screening of 3000 FDA-approved drugs, 7 retinoids with medical use were retrieved and used for molecular docking assays with TcPAT12. From the docked molecules, isotretinoin, a well-known drug used for acne treatment, showed the best interaction score with TcPAT12 and was selected for further in vitro studies. Isotretinoin inhibited the polyamine transport, as well as other amino acid transporters from the same protein family (TcAAAP), with calculated IC₅₀ values in the range of 4.6–10.3 μM. It also showed a strong inhibition of trypomastigote burst from infected cells, with calculated IC₅₀ of 130 nM (SI = 920) being significantly less effective on the epimastigote stage (IC₅₀ = 30.6 μM). The effect of isotretinoin on the parasites plasma membrane permeability and on mammalian cell viability was tested, and no change was observed. Autophagosomes and apoptotic bodies were detected as part of the mechanisms of isotretinoin-induced death indicating that the inhibition of transporters by isotretinoin causes nutrient starvation that triggers autophagic and apoptotic processes. In conclusion, isotretinoin is a promising trypanocidal drug since it is a multi-target inhibitor of essential metabolites transporters, in addition to being an FDA-approved drug largely used in humans, which could reduce significantly the requirements for its possible application in the treatment of Chagas disease.

Polyamines are polycationic compounds essential for the regulation of cell growth and differentiation. In contrast with other protozoa, Trypanosoma cruzi, the etiological agent of Chagas disease, is auxotrophic for polyamines; therefore the intracellular availability of these molecules depends exclusively on transport processes. It was previously demonstrated that the lack of polyamines in T. cruzi leads to its death, making the polyamine transporter an excellent therapeutic target for Chagas disease. In this work, the polyamine permease TcPAT12 was selected as a target for drug screening using 3000 FDA-approved compounds and computational simulation techniques. Using two combined virtual screening methods, isotretinoin, a well-known and safe drug used for acne treatment, bound to substrate recognition residues of TcPAT12 and was chosen for further in vitro studies. Isotretinoin inhibited not only the polyamine transport but also all tested amino acid transporters from the same protein family as TcPAT12. Interestingly, isotretinoin showed a high trypanocidal effect on trypomastigotes, with an IC₅₀ in the nanomolar range. Autophagy and apoptosis were proposed as mechanisms of parasites death induced by isotretinoin. These results suggest that isotretinoin is a promising trypanocidal drug, being a multi-target inhibitor of essential metabolites transporters.

Role of correction of metabolic disorders in the complex therapy of acne in women

The prevalence and genetic origin of acne explain the urgency of searching for new dermatosis treatment methods. The occurrence of acne in women is stipulated by hyperandrogynous conditions and is often accompanied with insulin resistance. The administration of Metformin in the complex therapy of acne in women with insulin resistance contributes to considerable improvement of the clinical course of dermatosis and achievement of remission for a greater number of patients.

Acne: treatment of scars

Acne is a common disease affecting a significant proportion of the population.(1-3) It causes considerable morbidity through soreness, disfigurement, and social handicap due to inflammatory lesions.(4,5) Modern therapy ensures that a considerable proportion of all patients can be offered effective treatment of their disease, but the morbidity is not restricted solely to the inflammatory lesions of acne.(6,7) Despite appropriate and effective primary prevention of scarring, scarring occurs in some degree in 95% of all patients irrespective of the severity of inflammatory acne (although severe acne causes more scarring than the milder forms). The scarring causes long-term morbidity that requires specific therapy.(7)

Medical treatment of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a common skin disease affecting an estimated 2% of the population. It causes significant symptoms and is notoriously difficult to treat. In this article, the current medical therapy is reviewed. At the present time, therapy appears to be based on an interpretation of the disease as either infectious or a form of acne. The understanding of the pathogenesis of HS suggests that these are not adequate models in order to understand the disease and this may explain the insufficiency of currently available medical treatment. The literature is sparse and there is a shortage of randomised, controlled trials. Three small, randomised, controlled trials have suggested that clindamycin, tetracycline and oestrogens and cyproteroneacetate may have an effect in some patients. Preceiving HS as an inflammatory skin disease suggests the use of general immunosuppressive drugs in the treatment of this condition. This approach, using both traditional immunosupressants and monoclonal antibodies, has been assessed in a small number of patients and appears to have some potential. However, the main source of evidence for this are case series and there is a strong need for more formal studies in this potentially debilitating disease.