The role and mechanism of action of 13-cis-retinoic acid in the treatment of severe (nodulocystic) acne

Efficacy and adverse events of oral isotretinoin for acne: a systematic review

Despite many years of clinical use of isotretinoin, a comprehensive review of evidence for isotretinoin therapy in patients with acne is lacking. We searched MEDLINE, Embase, Cochrane Central, relevant web pages and bibliographies for randomized controlled trials in acne evaluating isotretinoin vs. control (placebo or other therapy). Data were extracted and summarized descriptively. Eleven trials were identified (total 760 patients randomized), containing mostly men. Mean treatment ages ranged from 18 to 47·9 years and participants generally had moderate-to-severe acne. Across all trials, isotretinoin therapy reduced acne lesion counts by a clinically relevant amount, and always by a greater amount than control, which was either placebo (two studies), oral antibiotics (seven studies) or other control (two studies). Across trials with an overall low risk of bias, two of three demonstrated statistically significant differences between isotretinoin and control. The frequency of adverse events was twice as high with isotretinoin (751 events) than with control (388 events). More than half of all adverse events were dermatological and related to dryness. Adverse events from isotretinoin causing participant withdrawal from trials (12 patients) included Stevens-Johnson syndrome, cheilitis, xerosis, acne flare, photophobia, elevated liver enzymes, decreased appetite, headaches and depressed mood. This review suggests that isotretinoin is effective in reducing acne lesion counts, but adverse events are common. This study was registered with PROSPERO number CRD42015025080.

All-trans retinoic acid and rapamycin synergize with transforming growth factor-β1 to induce regulatory T cells but confer different migratory capacities

Tregs play important roles in maintaining immune homeostasis, and thus, therapies based on Treg are promising candidates for the treatment for a variety of immune-mediated disorders. These therapies, however, face the significant challenge of obtaining adequate numbers of Tregs from peripheral blood that maintains suppressive function following extensive expansion. Inducing Tregs from non-Tregs offers a viable alternative. Different methods to induce Tregs have been proposed and involve mainly treating cells with TGF-β-iTreg. However, use of TGF-β alone is not sufficient to induce stable Tregs. ATRA or rapa has been shown to synergize with TGF-β to induce stable Tregs. Whereas TGF-β plus RA-iTregs have been well-described in the literature, the phenotype, function, and migratory characteristics of TGF-β plus rapa-iTreg have yet to be elucidated. Herein, we describe the phenotype and function of mouse rapa-iTreg and reveal that these cells differ in their in vivo homing capacity when compared with mouse RA-iTreg and mouse TGF-β-iTreg. This difference in migratory activity significantly affects the therapeutic capacity of each subset in a mouse model of colitis. We also describe the characteristics of iTreg generated in the presence of TGF-β, RA, and rapa.

Urea co-inclusion compounds of 13 cis-retinoic acid for simultaneous improvement of dissolution profile, photostability and safe handling characteristics

13-cis Retinoic acid (cis-RA), a synthetic retinoid used in the treatment of severe acne, is known to exhibit extremely low aqueous solubility and high photosensitivity. In this study, urea, a well-known adductor for linear compounds, was successfully employed for the adduction of cis-RA — a substituted cyclic organic compound. Formation of urea inclusion compounds was confirmed by FTIR, DSC and XRD. A modified Zimmerschied calorimetric method was employed for the estimation of the minimum amount of rapidly adductible endocyte (RAE) required for adduction of cis-RA in urea. Urea–cis-RA-RAE inclusion compounds containing varying proportions of guests were prepared and their thermal behaviour studied by DSC. The inclusion compounds were found to have an improved dissolution profile as demonstrated by an overall increase in the dissolution efficiency. An accelerated photostability study, conducted as per Q1B ICH guidelines, revealed that co-inclusion of cis-RA in urea delayed photo-degradation of the drug when compared with that of the pure drug. The results suggest the possibility of exploiting co-inclusion of the drug in a urea host lattice for improved solubility, stability and reduced handling problems for cis-RA.

Isotretinoin therapy in acne vulgaris: a 10-year retrospective study in Singapore

BACKGROUND

The use of isotretinoin, a first generation synthetic retinoid, in the treatment of patients with severe acne vulgaris was a major therapeutic advance in dermatology. This 10-year retrospective study reviews the effectiveness of isotretinoin in patients with acne vulgaris seen in a skin clinic in Singapore.

METHODS

The case records of 250 cases of severe inflammatory and nodulocystic acne treated with isotretinoin were analyzed with reference to the demographic data, response to isotretinoin, dosage and cost of isotretinoin used, adverse effects, clinical follow-up, and relapse.

RESULTS

Two hundred and fifty patients, 171 men (68.4%) and 79 women (31.6%), with different types and grades of acne vulgaris were studied. The dose of isotretinoin used ranged from 0.33 to 1.0 mg/kg/day (median 0.5 mg/kg/day) for a period ranging from 1 to 12 months (median 4 months). Response was excellent in 127 (50.8%) patients, good in 86 (34.4%), fair in 30 (12.0%) and poor in 7 (2.8%). Relapse occurred in 14 (5.6%) patients over a 6-month follow-up period. Adverse effects were noted in 140 (56.0%) patients and were mild in most cases. Eighteen (7.2%) patients had to discontinue the drug due to significant side effects.

CONCLUSION

This study confirms that isotretinoin is very effective for severe acne, and complete remission can be induced in more than 90% of cases even with lower dosage regimens. Significant clinical improvement can be achieved with the use of lower doses (mean 0.5 mg/kg/day) for an average of 4 months of treatment with lower risk of adverse effects.

Acne vulgaris. Topical and systemic therapies

Acne vulgaris is a condition commonly treated by primary care physicians. An understanding of the causes of the disease and methods of clinical evaluation allows selection of appropriate therapy. Effective treatment is available for all types of acne, including severe, nodulocystic forms. Regardless of the regimen chosen, patients should receive encouragement and instructions about the necessity of regular ongoing treatment for a successful outcome.