Isotretinoin temporally regulates distinct sets of genes in patient skin

Therapeutic dosage of isotretinoin in rats may influence orthodontic tooth movement

Objective Isotretinoin, also known as 13-cis-retinoic acid, is an isomer of tretinoin, the oxidized form of Vitamin A. Orthodontic tooth movement (OTM) is the result of a cascade of inflammatory responses stimulated by a physical element that is the force generated by orthodontic appliances. Isotretinoin is mainly used among adolescents and young adults, and coincidentally it is this age group that also undergoes orthodontic treatment. Materials and Methods Fifty-five animals were used, and they were randomly divided into 11 groups, containing 5 animals in each group. Group 1: Control; Group 2: OTM for 7 days; Group 3: OTM for 14 days; Group 4: Treated with isotretinoin for 14 days with a dosage of 7.5 mg/kg/day; Group 5: Treated with isotretinoin for 14 days with a dosage of 1.0 mg/kg/day; Group 6: Treated with isotretinoin for 21 days with a dosage of 7.5 mg/kg/day; Group 7: Treated with isotretinoin for 21 days with a dosage of 1.0 mg/kg/day; Group 8: Treated with isotretinoin for 14 days with a dosage of 7.5 mg/kg/day and undergoing OTM for 7 days; Group 9: Treated with isotretinoin for 14 days with a dosage of 1.0 mg/kg/day and undergoing OTM for 7 days; Group 10: Treated with isotretinoin for 21 days with a dosage of 7.5 mg/kg/day and undergoing OTM for 14 days; Group 11: Treated with isotretinoin for 21 days with a dosage of 1.0 mg/kg/day and undergoing OTM for 14 days. In Groups 8, 9, 10 and 11, the animals were treated with isotretinoin for 7 days before OTM and maintained during the movement period in the respective groups. Results There was a significant difference in microtomographic parameters, including Trabecular Volume (BV/TV), Trabecular Thickness (Tb.Th), Number of Trabeculae (Tb.N), and Trabecular Separation (Tb.Sp), between the groups. The group that received orthodontic force in conjunction with isotretinoin treatment at a dosage of 7.5 mg/kg/day exhibited lower tooth displacement over a period of 21 days and 14 days. Conclusion Isotretinoin caused a reduction in tooth displacement during OTM when administered at a dose of 7.5 mg/kg/day and isotretinoin did change the microtomographic parameters of treated animals.

Acne Transcriptomics: Fundamentals of Acne Pathogenesis and Isotretinoin Treatment

This review on acne transcriptomics allows for deeper insights into the pathogenesis of acne and isotretinoin's mode of action. Puberty-induced insulin-like growth factor 1 (IGF-1), insulin and androgen signaling activate the kinase AKT and mechanistic target of rapamycin complex 1 (mTORC1). A Western diet (hyperglycemic carbohydrates and milk/dairy products) also co-stimulates AKT/mTORC1 signaling. The AKT-mediated phosphorylation of nuclear FoxO1 and FoxO3 results in their extrusion into the cytoplasm, a critical switch which enhances the transactivation of lipogenic and proinflammatory transcription factors, including androgen receptor (AR), sterol regulatory element-binding transcription factor 1 (SREBF1), peroxisome proliferator-activated receptor γ (PPARγ) and signal transducer and activator of transcription 3 (STAT3), but reduces the FoxO1-dependent expression of GATA binding protein 6 (GATA6), the key transcription factor for infundibular keratinocyte homeostasis. The AKT-mediated phosphorylation of the p53-binding protein MDM2 promotes the degradation of p53. In contrast, isotretinoin enhances the expression of p53, FoxO1 and FoxO3 in the sebaceous glands of acne patients. The overexpression of these proapoptotic transcription factors explains isotretinoin's desirable sebum-suppressive effect via the induction of sebocyte apoptosis and the depletion of BLIMP1(+) sebocyte progenitor cells; it also explains its adverse effects, including teratogenicity (neural crest cell apoptosis), a reduced ovarian reserve (granulosa cell apoptosis), the risk of depression (the apoptosis of hypothalamic neurons), VLDL hyperlipidemia, intracranial hypertension and dry skin.

Efficacy and safety of oral isotretinoin in the treatment of moderate to severe seborrheic dermatitis: a retrospective study

BACKGROUND AND OBJECTIVES

Seborrheic dermatitis is a common, chronic, and recurrent inflammatory skin disease. There are few studies on oral isotretinoin in the treatment of seborrheic dermatitis. The aim of this research was to analyze the efficacy and safety of oral isotretinoin in the treatment of patients with moderate to severe seborrheic dermatitis.

METHODS

This was a retrospective study. All included patients were diagnosed as moderate to severe seborrheic dermatitis and treated with oral isotretinoin from January 2019 to December 2020. Symptom Scale of Seborrheic Dermatitis (SSSD) was used to evaluate the overall severity status of disease.

RESULTS

A total of 48 patients with moderate to severe seborrheic dermatitis were enrolled, of which 26 patients were treated with oral isotretinoin at a dose of 20 mg/day, and 22 patients were treated with oral isotretinoin at a dose of 10 mg/day. The duration of treatment was 2.42 ± 0.98 months (range: 2-6 months). The absolute SSSD values were 10.63 ± 1.02 for all 48 patients, 10.95 ± 1.15 and 10.30 ± 1.11 for patients with a dose of 20 and 10 mg/day, respectively. At the endpoint, there were no significant difference in SSSD values between the two groups (2.21 ± 0.24 vs. 2.35 ± 0.46, P = 0.18). The patients were satisfied with the two treatment schemes, and the difference was not statistically significant (P = 0.78). The most common side effect was cheilitis; however, no serious adverse events occurred in either group.

CONCLUSIONS

When considering efficacy and safety, oral isotretinoin can be used to treat patients with moderate to severe seborrheic dermatitis.

Isotretinoin and its Metabolites Alter mRNA of Multiple Enzyme and Transporter Genes In Vitro, but Downregulation of Organic Anion Transporting Polypeptide Does Not Translate to the Clinic

Isotretinoin [13-cis-retinoic acid (13cisRA)] is widely used for the treatment of neuroblastoma and acne. It acts via regulating gene transcription through binding to retinoic acid receptors. Yet, the potential for isotretinoin to cause transcriptionally mediated drug-drug interactions (DDIs) has not been fully explored. We hypothesized that isotretinoin and its active metabolites all-trans-retinoic acid (atRA) and 4-oxo-13cisRA would alter the transcription of enzymes and transporters in the human liver via binding to nuclear receptors. The goal of this study was to define the DDI potential of isotretinoin and its metabolites resulting from transcriptional regulation of cytochrome P450 and transporter mRNAs. In human hepatocytes (n = 3), 13cisRA, atRA, and 4-oxo-13cisRA decreased OATP1B1, CYP1A2, CYP2C9, and CYP2D6 mRNA and increased CYP2B6 and CYP3A4 mRNA in a concentration-dependent manner. The EC50 values for OATP1B1 mRNA downregulation ranged from 2 to 110 nM, with maximum effect (Emax ) ranging from 0.17- to 0.54-fold. Based on the EC50 and Emax values and the known circulating concentrations of 13cisRA and its metabolites after isotretinoin dosing, a 55% decrease in OATP1B1 activity was predicted in vivo. In vivo DDI potential was evaluated clinically in participants dosed with isotretinoin for up to 32 weeks using coproporphyrin-I (CP-I) as an OATP1B1 biomarker. CP-I steady-state serum concentrations were unaltered following 2, 8, or 16 weeks of isotretinoin treatment. These data show that isotretinoin and its metabolites alter transcription of multiple enzymes and transporters in vitro, but translation of these changes to in vivo drug-drug interactions requires clinical evaluation for each enzyme. SIGNIFICANCE STATEMENT: Isotretinoin and its metabolites alter the mRNA expression of multiple cytochrome P450s (CYPs) and transporters in human hepatocytes, suggesting that isotretinoin may cause clinically significant drug-drug interactions (DDIs). Despite the observed changes in organic anion transporting polypeptide 1B1 (OATP1B1) mRNA in human hepatocytes, no clinical DDI was observed when measuring a biomarker, coproporphyrin-I. Further work is needed to determine whether these findings can be extrapolated to a lack of a DDI with CYP1A2, CYP2B6, and CYP2C9 substrates.

The impact of isotretinoin on the pituitary-ovarian axis: An interpretative review of the literature

Isotretinoin (13-cis-retinoic acid), a derivative of vitamin A, is used in the treatment of severe acne resulting in sebum suppression induced by sebocyte apoptosis. Isotretinoin treatment is associated with several adverse effects including teratogenicity, hepatotoxicity, and dyslipidemia. Isotretinoin's effects on endocrine systems and its potential role as an endocrine disruptor are not yet adequately investigated. This review presents clinical, endocrine, and molecular evidence showing that isotretinoin treatment adversely affects the pituitary-ovarian axis and enhances the risk of granulosa cell apoptosis reducing follicular reserve. Isotretinoin is associated with pro-apoptotic signaling in sebaceous glands through upregulated expression of p53, forkhead box O transcription factors (FOXO1, FOXO3), and tumor necrosis factor-related apoptosis inducing ligand (TRAIL). Two literature searches including clinical and experimental studies respectively support the hypothesis that isotretinoin's toxicological mode of action on the pituitary-ovarian axis might be caused by over-expressed p53/FOXO1 signaling resulting in gonadotropin suppression and granulosa cell apoptosis. The reduction of follicular reserve by isotretinoin treatment should be especially considered when this drug will be administered for the treatment of acne in post-adolescent women, in whom fertility may be adversely affected. In contrast, isotretinoin treatment may exert beneficial effects in states of hyperandrogenism, especially in patients with polycystic ovary syndrome.

Consensus on the use of oral isotretinoin in dermatology - Brazilian Society of Dermatology

BACKGROUND

Isotretinoin is a synthetic retinoid, derived from vitamin A, with multiple mechanisms of action and highly effective in the treatment of acne, despite common adverse events, manageable and dose-dependent. Dose-independent teratogenicity is the most serious. Therefore, off-label prescriptions require strict criteria.

OBJECTIVE

To communicate the experience and recommendation of Brazilian dermatologists on oral use of the drug in dermatology.

METHODS

Eight experts from five universities were appointed by the Brazilian Society of Dermatology to develop a consensus on indications for this drug. Through the adapted DELPHI methodology, relevant elements were listed and an extensive analysis of the literature was carried out. The consensus was defined with the approval of at least 70% of the experts.

RESULTS

With 100% approval from the authors, there was no doubt about the efficacy of oral isotretinoin in the treatment of acne, including as an adjunct in the correction of scars. Common and manageable common adverse events are mucocutaneous in nature. Others, such as growth retardation, abnormal healing, depression, and inflammatory bowel disease have been thoroughly investigated, and there is no evidence of a causal association; they are rare, individual, and should not contraindicate the use of the drug. Regarding unapproved indications, it may represent an option in cases of refractory rosacea, severe seborrheic dermatitis, stabilization of field cancerization with advanced photoaging and, although incipient, frontal fibrosing alopecia. For keratinization disorders, acitretin performs better. In the opinion of the authors, indications for purely esthetic purposes or oil control are not recommended, particularly for women of childbearing age.

CONCLUSIONS

Approved and non-approved indications, efficacy and adverse effects of oral isotretinoin in dermatology were presented and critically evaluated.

Isotretinoin and the Kidney: Opportunities and Threats

Retinoids are one of the most effective drugs in inducing complete or prolonged remission of severe acne vulgaris, but the adverse reactions associated with the use of them are raising a concern about the potential effect of these drugs on internal organs function such as the kidney. The aim of this review is to comprehensively gather data about isotretinoin, both potential adverse and beneficial effects on the kidney based on the current experimental and clinical findings. Very few studies, including five case reports, described that systemic oral isotretinoin within usual doses (40 mg/day or 0.5 mg/kg⁄day) within 1 to 4 months of treatment might be associated with different types of renal dysfunctions. These include acute interstitial nephritis, nephrotic syndrome, and hematuria with dysuria. The adverse reactions of systemic isotretinoin on the kidney and urinary system are unlikely and rare. In contrast, six experimental studies demonstrated the beneficial effects of either oral or parenteral low- (2 or 5 mg/kg/day) or high- (10, 20, 25, 40 mg/kg/day) dose isotretinoin on the kidney in the rat models of glomerulonephritis, obstructive nephropathy or allograft nephropathy. The nephroprotective functions of isotretinoin in these studies were attributed to its anti-proliferative, anti-fibrotic, and anti-inflammatory actions. However, clinical studies are warranted to elucidate the possible beneficial effects of isotretinoin in preventing or attenuating kidney injury in different settings.

The use of isotretinoin for acne - an update on optimal dosing, surveillance, and adverse effects

INTRODUCTION

Acne is a chronic, inflammatory, and immune mediated disease of pilosebaceous unit, highly prevalent in adolescents. It involves face, trunk, and back; may leave scars and affect quality of life. Early, effective, and safe treatment is the key for disease resolution. Oral isotretinoin is the unique treatment for cure or prolonged remission for moderate and severe acne, preventing psychosocial impact and scars. It inhibits sebaceous glands activity and has anti-inflammatory and immunoregulatory properties.

AREAS COVERED

We performed a comprehensive literature search on PubMed database, up to March 2020, regarding oral isotretinoin for acne treatment. We synthetized data about acne pathogenesis and mechanism of action, efficacy, and safety of isotretinoin.

EXPERT OPINION

This drug is effective, despite common, controllable, and reversible mucocutaneous side effects. Serious adverse events are rare and represent individual reactions. Teratogenicity is the most severe, requiring rigorous control. We believe that no other therapeutic option, even topicals combined to oral antibiotics accomplish same results. Recurrence after treatments other than isotretinoin is the rule, prolonging risk of scars, compromising skin appearance, and causing emotional distress in teenagers. If there is no absolute contraindication, isotretinoin should be the first line treatment for moderate to severe inflammatory acne.

Putative Genes and Pathways Involved in the Acne Treatment of Isotretinoin via Microarray Data Analyses

Acne is the eighth most common disease worldwide. Disease burden of acne such as anxiety, reduced self-esteem, and facial scarring lowers the life quality of acne patients. Isotretinoin is the most potent treatment for moderate-severe acne. However, the adverse events of isotretinoin especially teratogenicity limit its use. This study aims at investigating the therapeutical mechanisms of isotretinoin using bioinformatics analysis. Differentially expressed genes (DEGs) were filtered from microarray datasets GSE10432, GSE10433, and GSE11792. Functional and pathway enrichment analyses of DEGs were performed. Protein–protein interaction (PPI) network and module analyses were also conducted based on DEGs. Using isotretinoin for 1 week, LCN2, PTGES, and GDF15 were upregulated and might mediate sebocytes apoptosis and thus decreased sebum production; CCL2 originated from activated TNF signaling pathway and S100A7 could be related with “acne-flare”. While treating with isotretinoin for 8 weeks, key genes were downregulated, including HMGCS1, HMGCR, FDFT1, MVD, IDI1, and FDPS, which may be associated with decreased sebum synthesis; HMGCS1, HMGCR, and FDFT1 also probably associated with apoptosis of sebocytes. There were only two common genes including ACSBG1 and BCAT2 which worked in both 1 week and 8 weeks and could associate with decreased sebum synthesis and apoptosis of sebocytes, respectively. These results indicate potential therapeutics and side effect mechanisms of isotretinoin in the acne treatment and provide a research direction to further investigate the therapeutic mechanism of isotretinoin and thus develop retinoid-like compounds with similar curative effect and without teratogenicity.

Oily sensitive skin: A review of management options

BACKGROUND

Due to the ever-increasing demands for the personalized care, people seek for the tailored management according to the accurate identification of their skin type. The Baumann Skin Type Indicator, which was proposed by Leslie Baumann, is composed of four parameters: oily or dry, resistant or sensitive, pigmented or nonpigmented, and wrinkled or tight. Among these, oily sensitive skin experiences significant discomfort and resists ordinary treatment.

AIMS

In this article, we will review the clinical manifestations, underlying pathogenesis and recommendations on treatment options that may be utilized to help patients with oily sensitive skin.

PATIENTS/METHODS

Literature search was conducted using PubMed. The literature concerning Baumann Skin Type Indicator and oily sensitive skin type were considered.

RESULTS

Oily sensitive (OS)-type skin is a complex of oily and sensitive skin that causes significant discomfort and undergoes stubborn resistance to treatments. Sebum dysfunction and hypersensitivity may play a key role in the development of sensitive skin. Considering the pathogenesis of OS-type skin, treatment should focus on both seborrhea and hypersensitivity.

CONCLUSION

Clinicians can effectively treat the oily sensitive skin by understanding underlying pathogenesis of it. Further investigations are necessary to reach a consensus on the basic pathophysiology and optimal management guidelines for oily sensitive skin.

Oral isotretinoin for acne

BACKGROUND

Acne vulgaris, a chronic inflammatory disease of the pilosebaceous unit associated with socialisation and mental health problems, may affect more than 80% of teenagers. Isotretinoin is the only drug that targets all primary causal factors of acne; however, it may cause adverse effects.

OBJECTIVES

To assess efficacy and safety of oral isotretinoin for acne vulgaris.

SEARCH METHODS

We searched the following databases up to July 2017: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO and LILACS. We updated this search in March 2018, but these results have not yet been incorporated in the review. We also searched five trial registries, checked the reference lists of retrieved studies for further references to relevant trials, and handsearched dermatology conference proceedings. A separate search for adverse effects of oral isotretinoin was undertaken in MEDLINE and Embase up to September 2013.

SELECTION CRITERIA

Randomised clinical trials (RCTs) of oral isotretinoin in participants with clinically diagnosed acne compared against placebo, any other systemic or topical active therapy, and itself in different formulation, doses, regimens, or course duration.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 31 RCTs, involving 3836 participants (12 to 55 years) with mild to severe acne. There were twice as many male participants as females.Most studies were undertaken in Asia, Europe, and North America. Outcomes were generally measured between eight to 32 weeks (mean 19.7 weeks) of therapy.Assessed comparisons included oral isotretinoin versus placebo or other treatments such as antibiotics. In addition, different doses, regimens, or formulations of oral isotretinoin were assessed, as well as oral isotretinoin with the addition of topical agents.Pharmaceutical companies funded 12 included trials. All, except three studies, had high risk of bias in at least one domain.Oral isotretinoin compared with oral antibiotics plus topical agentsThese studies included participants with moderate or severe acne and assessed outcomes immediately after 20 to 24 weeks of treatment (short-term). Three studies (400 participants) showed isotretinoin makes no difference in terms of decreasing trial investigator-assessed inflammatory lesion count (RR 1.01 95% CI 0.96 to 1.06), with only one serious adverse effect found, which was Stevens-Johnson syndrome in the isotretinoin group (RR 3.00, 95% CI 0.12 to 72.98). However, we are uncertain about these results as they were based on very low-quality evidence.Isotretinoin may slightly improve (by 15%) acne severity, assessed by physician's global evaluation (RR 1.15, 95% CI 1.00 to 1.32; 351 participants; 2 studies), but resulted in more less serious adverse effects (67% higher risk) (RR 1.67, 95% CI 1.42 to 1.98; 351 participants; 2 studies), such as dry lips/skin, cheilitis, vomiting, nausea (both outcomes, low-quality evidence).Different doses/therapeutic regimens of oral isotretinoinFor our primary efficacy outcome, we found three RCTs, but heterogeneity precluded meta-analysis. One study (154 participants) reported 79%, 80% and 84% decrease in total inflammatory lesion count after 20 weeks of 0.05, 0.1, or 0.2 mg/kg/d of oral isotretinoin for severe acne (low-quality evidence). Another trial (150 participants, severe acne) compared 0.1, 0.5, and 1 mg/kg/d oral isotretinoin for 20 weeks and, respectively, 58%, 80% and 90% of participants achieved 95% decrease in total inflammatory lesion count. One RCT, of participants with moderate acne, compared isotretinoin for 24 weeks at (a) continuous low dose (0.25 to 0.4 mg/kg/day), (b) continuous conventional dose (0.5 to 0.7 mg/kg/day), and (c) intermittent regimen (0.5 to 0.7 mg/kg/day, for one week in a month). Continuous low dose (MD 3.72 lesions; 95% CI 2.13 to 5.31; 40 participants; one study) and conventional dose (MD 3.87 lesions; 95% CI 2.31 to 5.43; 40 participants; one study) had a greater decrease in inflammatory lesion counts compared to intermittent treatment (all outcomes, low-quality evidence).Fourteen RCTs (906 participants, severe and moderate acne) reported that no serious adverse events were observed when comparing different doses/therapeutic regimens of oral isotretinoin during treatment (from 12 to 32 weeks) or follow-up after end of treatment (up to 48 weeks). Thirteen RCTs (858 participants) analysed frequency of less serious adverse effects, which included skin dryness, hair loss, and itching, but heterogeneity regarding the assessment of the outcome precluded data pooling; hence, there is uncertainty about the results (low- to very-low quality evidence, where assessed).Improvement in acne severity, assessed by physician's global evaluation, was not measured for this comparison.None of the included RCTs reported birth defects.

AUTHORS' CONCLUSIONS

Evidence was low-quality for most assessed outcomes.We are unsure if isotretinoin improves acne severity compared with standard oral antibiotic and topical treatment when assessed by a decrease in total inflammatory lesion count, but it may slightly improve physician-assessed acne severity. Only one serious adverse event was reported in the isotretinoin group, which means we are uncertain of the risk of serious adverse effects; however, isotretinoin may result in more minor adverse effects.Heterogeneity in the studies comparing different regimens, doses, or formulations of oral isotretinoin meant we were unable to undertake meta-analysis. Daily treatment may be more effective than treatment for one week each month. None of the studies in this comparison reported serious adverse effects, or measured improvement in acne severity assessed by physician's global evaluation. We are uncertain if there is a difference in number of minor adverse effects, such as skin dryness, between doses/regimens.Evidence quality was lessened due to imprecision and attrition bias. Further studies should ensure clearly reported long- and short-term standardised assessment of improvement in total inflammatory lesion counts, participant-reported outcomes, and full safety accounts. Oral isotretinoin for acne that has not responded to oral antibiotics plus topical agents needs further assessment, as well as different dose/regimens of oral isotretinoin in acne of all severities.

Treatment of seborrheic dermatitis: a comprehensive review

Seborrheic dermatitis (SD) is a chronic, recurring inflammatory skin disorder that manifests as erythematous macules or plaques with varying levels of scaling associated with pruritus. The condition typically occurs as an inflammatory response to Malassezia species and tends to occur on seborrheic areas, such as the scalp, face, chest, back, axilla, and groin areas. SD treatment focuses on clearing signs of the disease; ameliorating associated symptoms, such as pruritus; and maintaining remission with long-term therapy. Since the primary underlying pathogenic mechanisms comprise Malassezia proliferation and inflammation, the most commonly used treatment is topical antifungal and anti-inflammatory agents. Other broadly used therapies include lithium gluconate/succinate, coal tar, salicylic acid, selenium sulfide, sodium sulfacetamide, glycerin, benzoyl peroxide, aloe vera, mud treatment, phototherapy, among others. Alternative therapies have also been reported, such as tea tree oil, Quassia amara, and Solanum chrysotrichum. Systemic therapy is reserved only for widespread lesions or in cases that are refractory to topical treatment. Thus, in this comprehensive review, we summarize the current knowledge on SD treatment and attempt to provide appropriate directions for future cases that dermatologists may face.

Consensus-Based Acne Classification System and Treatment Algorithm for Spain

Acne is a chronic inflammatory disease whose psychosocial effects can greatly impair quality of life. Various scales are used to classify the severity of acne, and several treatment algorithms are currently applied: no consensus on a common scale or treatment guidelines has been reached. A group of Spanish experts therefore met to identify a scale the majority could accept as the most appropriate for classifying severity and treating accordingly. The group chose the following classifications: comedonal acne, mild or moderate papulopustular acne, severe papulopustular acne, moderate nodular acne, and nodular-cystic acne (or acne tending to leave scars). Consensus was reached on first- and second-choice treatments for each type and on maintenance treatment. The experts also issued specific recommendations on antibiotic use (starting with mild or moderate papulopustular acne), always in combination with retinoids and/or benzoyl peroxide. The use of isotretinoin (starting at severe papulopustular or moderate nodular acne) was also covered.

Systemic treatment of severe forms of acne: experience of using Isotretinoin in the Russian Federation

The article presents the results of a large-scale Russian program of the follow-up and treatment of acne patients with Isotretinoin (Roaccutane). The analysis of the results included information about 1,349 acne patients. In 71% of patients, the therapy was initiated at the dose of 0.5-1.0 mg/kg of the body weight. The average duration of treatment was 21.5±0.16 weeks while the average course dose was 119.9±0.8 mg/kg of the body weight. As many as 96% of patients achieved a positive result; women demonstrated a higher improvement rate than men. On the whole, Roaccutane was well-tolerated while adverse effects included dry lips (43.4%), dry skin in different areas (12.45%), retinoid dermatitis (6.45%), epistaxis (2.45%), conjunctivitis (1.41%) and hoarseness (0.22%). The Russian experience of using Roaccutane confirmed high efficacy of the systemic therapy for severe forms of acne.

Endogenous retinoids in the hair follicle and sebaceous gland

Vitamin A and its derivatives (retinoids) are critically important in the development and maintenance of multiple epithelial tissues, including skin, hair, and sebaceous glands, as shown by the detrimental effects of either vitamin A deficiency or toxicity. Thus, precise levels of retinoic acid (RA, active metabolite) are needed. These precise levels of RA are achieved by regulating several steps in the conversion of dietary vitamin A (retinol) to RA and RA catabolism. This review discusses the localization of RA synthesis to specific sites within the hair follicle and sebaceous gland, including their stem cells, during both homeostasis and disease states. It also discusses what is known about the specific roles of RA within the hair follicle and sebaceous gland. This article is part of a Special Issue entitled: Retinoid and Lipid Metabolism.

Isotretinoin increases skin-surface levels of neutrophil gelatinase-associated lipocalin in patients treated for severe acne

BACKGROUND

A clear-cut need exists for safe and effective alternatives to the use of isotretinoin in severe acne. Lack of data regarding the specifics of isotretinoin's mechanism of action has hampered progress in this area. Recently, the protein neutrophil gelatinase-associated lipocalin (NGAL) has been identified as a mediator of the apoptotic effect of isotretinoin on sebocytes.

OBJECTIVES

To establish further the clinical relevance of NGAL and to elucidate the factors that induce NGAL expression in sebocytes.

METHODS

Methods were developed to isolate and quantify skin-surface levels of NGAL from normal subjects and patients with acne undergoing treatment with isotretinoin.

RESULTS

Patients with acne were found to have higher skin levels of NGAL compared with normal subjects. Studies in SEB-1 sebocytes indicate that NGAL expression is increased in response to Propionibacterium acnes and interleukin (IL)-1β. In patients, isotretinoin increases NGAL levels by 2·4-fold on the skin surface and this increase precedes decreases in sebum and P. acnes counts.

CONCLUSIONS

These data support the hypothesis that NGAL is an important mediator of the early effects of isotretinoin on the sebaceous glands and provide insights into the mechanisms that regulate NGAL expression in the skin.

Isotretinoin and FoxO1: A scientific hypothesis

Oral isotretinoin (13-cis retinoic acid) is the most effective drug in the treatment of acne and restores all major pathogenetic factors of acne vulgaris. isotretinoin is regarded as a prodrug which after isomerizisation to all-trans-retinoic acid (ATRA) induces apoptosis in cells cultured from human sebaceous glands, meibomian glands, neuroblastoma cells, hypothalamic cells, hippocampus cells, Dalton's lymphoma ascites cells, B16F-10 melanoma cells, and neuronal crest cells and others. By means of translational research this paper provides substantial indirect evidence for isotretinoin's mode of action by upregulation of forkhead box class O (FoxO) transcription factors. FoxOs play a pivotal role in the regulation of androgen receptor transactivation, insulin/insulin like growth factor-1 (IGF-1)-signaling, peroxisome proliferator-activated receptor-γ (PPArγ)- and liver X receptor-α (LXrα)-mediated lipogenesis, β-catenin signaling, cell proliferation, apoptosis, reactive oxygene homeostasis, innate and acquired immunity, stem cell homeostasis, as well as anti-cancer effects. An accumulating body of evidence suggests that the therapeutic, adverse, teratogenic and chemopreventive effecs of isotretinoin are all mediated by upregulation of FoxO-mediated gene transcription. These FoxO-driven transcriptional changes of the second response of retinoic acid receptor (RAR)-mediated signaling counterbalance gene expression of acne due to increased growth factor signaling with downregulated nuclear FoxO proteins. The proposed isotretinoin→ATRA→RAR→FoxO interaction offers intriguing new insights into the mode of isotretinoin action and explains most therapeutic, adverse and teratogenic effects of isotretinoin in the treatment of acne by a common mode of FoxO-mediated transcriptional regulation.