Prolonged remissions of cystic and conglobate acne with 13-cis-retinoic acid

Evaluation of the clinical efficacy of the 1,450 nm laser in acne vulgaris: a randomized split-face, investigator-blinded clinical trial

BACKGROUND

  The 1450 nm laser shrinks sebaceous glands histologically, reduces seborrhoea and has been shown in numerous small uncontrolled studies to improve inflammatory acne.

OBJECTIVES

To assess objectively the clinical efficacy and long-term outcome of the 1450 nm laser for inflammatory acne vulgaris.

METHODS

Participants over 16 years of age with moderate to severe acne vulgaris were recruited from a secondary care dermatology department. A split-face format was used: the side of the face to be treated was randomized with the other side serving as a within-patient control. Treatment was delivered with the Candela 1450 nm Smoothbeam laser (Candela, Cwmbran, U.K.) using a double-pass technique, 6 mm spot size, 210 ms pulse duration and fluence of 8 or 9 J cm(-2) . Three treatments were performed monthly. The primary outcome was the change in inflammatory lesion count and grading (using the Leeds Revised Acne Grading Scale) between baseline and 4 weeks after the third treatment on the treated side as compared with the change in the control side. Participants were followed up every 3 months for 12 months after the last treatment. The single assessor was blinded as to the side treated.

RESULTS

Thirty-eight participants entered the study and 32 completed the study at the primary outcome measure. Within participants, on average, the lesion count reduced by the same amount on both sides of the face [median 0, 95% confidence interval (CI) -4 to 2]. On average, acne grade reduced by the same amount on both sides (median 0, 95% CI -1 to 0). Twelve months after the last treatment (n = 23) the change in lesion count and grade between the treated and control sides of the face remained similar. Treatment was well tolerated.

CONCLUSIONS

Treatment with the 1450 nm laser does not reduce inflammatory lesion count or acne grade when compared with a control side, using a split-face format in participants recruited from secondary care. Both sides of the face improved and a systemic effect of the laser is possible.

Retinoic acid and affective disorders: the evidence for an association

OBJECTIVE

Isotretinoin (13-cis-retinoic acid), approved by the US Food and Drug Administration for the treatment of acne, carries a black box warning related to the risk of depression, suicide, and psychosis. Retinoic acid, the active form of vitamin A, regulates gene expression in the brain, and isotretinoin is its 13-cis isomer. Retinoids represent a group of compounds derived from vitamin A that perform a large variety of functions in many systems, in particular the central nervous system, and abnormal retinoid levels can have neurologic effects. Although infrequent, proper recognition and treatment of psychiatric side effects in acne patients is critical given the risk of death and disability. This article reviews the evidence for isotretinoin's relationships with depression and suicidality.

DATA SOURCES

The PsycINFO, MEDLINE, and PubMed searchable database indexes were searched for articles published in the English language from 1960 to June 2010 using the key words isotretinoin, retinoids, retinoic acid, depression, depressive disorders, and vitamin A. Evidence examined includes (1) case reports; (2) temporal association between onset of depression and exposure to the drug; (3) challenge-rechallenge cases; (4) class effect (other compounds in the same class, like vitamin A, having similar neuropsychiatric effects); (5) dose response; and (6) biologically plausible mechanisms.

STUDY SELECTION

All articles in the literature related to isotretinoin, depression, and suicide were reviewed, as well as articles related to class effect, dose response, and biologic plausibility.

DATA EXTRACTION

Information from individual articles in the literature was extracted, including number of episodes of depression, suicidality, suicide, psychosis, violence and aggression, past psychiatric history, time of onset in relation to isotretinoin usage, medication dosage, duration of treatment, and dechallenge and challenge history.

RESULTS

The literature reviewed is consistent with associations of isotretinoin administration with depression and with suicide in a subgroup of vulnerable individuals.

CONCLUSIONS

The relationship between isotretinoin and depression may have implications for a greater understanding of the neurobiology of affective disorders.

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.

Resveratrol-containing gel for the treatment of acne vulgaris: a single-blind, vehicle-controlled, pilot study

BACKGROUND

Acne vulgaris is a complex, chronic, and common skin disorder of pilosebaceous units. The major pathogenic factors involved are ductal hyperkeratinization, obstruction of sebaceous follicles resulting from abnormal keratinization of the infundibular epithelium, stimulation of sebaceous gland secretion by androgens, and microbial colonization of pilosebaceous units by Propionibacterium acnes, which promotes perifollicular inflammation.

AIM

The aim of the study was to investigate the therapeutic effects of resveratrol, a natural phytoalexin produced by some spermatophytes, such as grapes and other plants, on acneic skin.

METHODS

Resveratrol was incorporated in a carboxymethylcellulose-based gel. The chemical stability of resveratrol after storage at 4°C for 30 days was investigated by high-performance liquid chromatography (HPLC). The resveratrol-containing hydrogel was administered to 20 patients affected by acne vulgaris enrolled in this single-blind study. The resveratrol-containing formulation was applied daily as a solo treatment on the right side of the face for 60 days, while the hydrogel vehicle was applied to the left side of the face as a control. To objectively evaluate the results, a digital photographic database was used to collect images. The number and type of lesions were recorded for each patient, to compare the Global Acne Grading System (GAGS) score before treatment with that obtained at the end of the study. Moreover, with the innovative technique of follicular biopsy, areas of acneic skin were prepared for histopathology. The average area occupied by microcomedones at baseline was compared with that at the end of treatment.

RESULTS

HPLC analysis demonstrated that resveratrol, upon incorporation into the gel, did not convert to its cis-isomer when stored at 4°C for 30 days. All patients were satisfied with the active treatment and none experienced adverse effects. Clinical evaluation showed a 53.75% mean reduction in the GAGS score on the resveratrol-treated sides of the face compared with 6.10% on the vehicle-treated sides of the face. These data were supported by histologic analysis, which showed a 66.7% mean reduction in the average area of microcomedones on the resveratrol-treated sides of the face. The comparison with the vehicle-treated side of the face (9.7% reduction) showed a clinically relevant and statistically significant decrease of lesions in areas treated with resveratrol-containing hydrogel.

CONCLUSION

This pilot study showed positive results for resveratrol gel in acne, and should be considered a valid starting point for further testing of the effectiveness of this molecule in different concentrations and formulations and in a larger group of patients.

FoxO1 - the key for the pathogenesis and therapy of acne?

Five main factors play a pivotal role in the pathogenesis of acne: androgen dependence, follicular retention hyperkeratosis, increased sebaceous lipogenesis, increased colonization with P. acnes, and inflammatory events. This paper offers a solution for the pathogenesis of acne and explains all major pathogenic factors at the genomic level by a relative deficiency of the nuclear transcription factor FoxO1. Nuclear FoxO1 suppresses androgen receptor, other important nuclear receptors and key genes of cell proliferation, lipid biosynthesis and inflammatory cytokines. Elevated growth factors during puberty and persistent growth factor signals due to Western life style stimulate the export of FoxO1 out of the nucleus into the cytoplasm via activation of the phos-phoinositide-3-kinase (PI3K)/Akt pathway. By this mechanism, genes and nuclear receptors involved in acne are derepressed leading to increased androgen receptor-mediated signal transduction, increased cell proliferation of androgen-dependent cells, induction of sebaceous lipogenesis and upregulation of Toll-like-receptor-2-dependent inflammatory cytokines. All known acne-inducing factors exert their action by reduction of nuclear FoxO1 levels. In contrast, retinoids, antibiotics and dietary intervention will increase the nuclear content of FoxO1, thereby normalizing increased transcription of genes involved in acne. Various receptor-mediated growth factor signals are integrated at the level of PI3K/Akt activation which finally results in nuclear FoxO1 deficiency.

[How acne vulgaris develops]

For the initiation of acne multiple factors are required from endogenous to exogenous sources. The morphogenesis of acne is well studied, and the principle steps are discussed in the paper. Acne is a disease of humans, developing in sebaceous follicles. The first step is a proliferation-retention hyperkeratosis in the infundibulum, thus forming a follicular filament, from which a microcomedo arises. Finally open and closed comedones appear. This sequence is not strictly followed, but quite typical. Androgen stimulation activates sebaceous lipogenesis. At this point propionibacteria colonize the follicle and comedones. At earlier or later stages of the comedo development inflammatory phenomena appear, ranging from subtle to severe. Depending on the amount of inflammation, scars may develop. There is an undisputable genetic component for the initiation of acne, as twin studies have shown. The or these genetic factors have not been determined yet. The inflammatory cascade is up-regulated by immunological factors. Exogenous factors, underestimated in the past, seem to play an important role as well, as epidemiological studies and recent publications from different investigators have shown. Nutrition, particularly hyperglycemic food and milk products, are directly involved in the pathogenesis of acne.

Systemic isotretinoin in the treatment of rosacea - doxycycline- and placebo-controlled, randomized clinical study

BACKGROUND

Systemic isotretinoin has been known for decades to be effective in the treatment of severe forms of rosacea, but it must be used off-label because of the lack of evidence-based data.

PATIENTS AND METHODS

573 patients with rosacea subtype II and III received one of three different dosages of isotretinoin (0.1 mg, 0.3 mg, or 0.5 mg per kg body weight), doxycycline (100 mg daily for 14 days, then 50 mg daily) or placebo in a double-blinded, randomized way for 12 weeks in 35 German centers.

RESULTS

Isotretinoin 0.3 mg/kg proved to be the most effective dose with significant superiority versus placebo. Isotretinoin 0.3 mg/kg showed also significant non-inferiority versus doxycycline with reduction of lesions of 90 % compared to 83 % with doxycycline. Investigators diagnosed complete remission in 24 % and marked improvement in further 57 % of patients with isotretinoin treatment, in contrast to remission in 14 % and marked improvement in 55 % of patients treated with doxycycline. Isotretinoin 0.3 mg/kg revealed a similar safety profile as for the treatment of acne. Isotretinoin 0.5 mg/kg showed more dermatitis facialis as compared to 0.3 mg/kg.

CONCLUSIONS

Isotretinoin 0.3 mg/kg is an effective and well-tolerated therapy option for the treatment of rosacea subtype II and III and can therefore be used successfully as an alternative to therapy with oral antibiotics.

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.

Chiral toxicology: it's the same thing...only different

Chiral substances possess a unique architecture such that, despite sharing identical molecular formulas, atom-to-atom linkages, and bonding distances, they cannot be superimposed. Thus, in the environment of living systems, where specific structure-activity relationships may be required for effect (e.g., enzymes, receptors, transporters, and DNA), the physiochemical and biochemical properties of racemic mixtures and individual stereoisomers can differ significantly. In drug development, enantiomeric selection to maximize clinical effects or mitigate drug toxicity has yielded both success and failure. Further complicating genetic polymorphisms in drug disposition, stereoselective metabolism of chiral compounds can additionally influence pharmacokinetics, pharmacodynamics, and toxicity. Optically pure pharmaceuticals may undergo racemization in vivo, negating single enantiomer benefits or inducing unexpected effects. Appropriate chiral antidotes must be selected for therapeutic benefit and to minimize adverse events. Enantiomers may possess different carcinogenicity and teratogenicity. Environmental toxicology provides several examples in which compound bioaccumulation, persistence, and toxicity show chiral dependence. In forensic toxicology, chiral analysis has been applied to illicit drug preparations and biological specimens, with the potential to assist in determination of cause of death and aid in the correct interpretation of substance abuse and "doping" screens. Adrenergic agonists and antagonist, nonsteroidal anti-inflammatory agents, SSRIs, opioids, warfarin, valproate, thalidomide, retinoic acid, N-acetylcysteine, carnitine, penicillamine, leucovorin, glucarpidase, pesticides, polychlorinated biphenyls, phenylethylamines, and additional compounds will be discussed to illustrate important concepts in "chiral toxicology."

Experiência de 65 anos no tratamento da acne e de 26 anos com isotretinoína oral

Este artigo especial foi extraído de uma palestra proferida pelo Prof. Sebastião Sampaio e elaborado em conjunto com a Profa Edileia Bagatin. Reflete a experiência dos autores no tratamento das principais formas de acne nos períodos pré e pós a introdução da isotretinoína oral que revolucionou a abordagem da doença. Esta droga representa a única opção capaz de levar à remissão prolongada ou cura da acne por atuar em todos os mecanismos etiopatogênicos conhecidos até o momento. Evidentemente, deve ser prescrita de acordo com as recomendações vigentes e reservada para casos de difícil controle, com tendência a cicatrizes e com sérias repercussões psico-sociais. Outras modalidades terapêuticas, tópicas e/ou sistêmicas, devem ser consideradas no início do tratamento e nos casos de intensidade leve a moderada.

Bone mineral density and bone turnover markers in patients receiving a single course of isotretinoin for nodulocystic acne

BACKGROUND

High-dose isotretinoin has been reported to have adverse effects on bone mineral density (BMD); however, studies evaluating changes in BMD with isotretinoin therapy at different dosages and with varying treatment durations have produced conflicting results.

OBJECTIVE

To investigate the effect of a standard, single course of isotretinoin therapy on BMD and bone turnover markers in patients with nodulocystic acne.

METHODS

Thirty-six patients (15 male, 21 female) with severe, recalcitrant, nodulocystic acne and 36 healthy controls (16 male, 20 female) were enrolled in the study. Patients received isotretinoin treatment for 4-6 months until a cumulative dose of 120 mg/kg had been achieved. BMD in the lumbar spine and femur was measured at baseline and at the end of therapy by dual-energy X-ray absorptiometry. Serum calcium, phosphate, parathormone, total alkaline phosphatase, osteocalcin, free deoxypyridinoline, and urinary calcium were also measured before and at the end of treatment.

RESULTS

No significant differences were found in lumbar spine and femoral BMD between the patient and control groups at the beginning of the study (P > 0.05), and no statistically significant difference was observed between the BMD values in patients at the beginning vs. the end of treatment (P > 0.05). No statistically significant difference in bone turnover markers was found between patients and controls at the beginning of the study (P > 0.05), and no statistically significant changes in bone turnover markers were observed in patients at the beginning vs. the end of treatment (P > 0.05).

CONCLUSION

A single course of isotretinoin therapy has no clinically significant effect on bone metabolism.

Neutrophil gelatinase-associated lipocalin mediates 13-cis retinoic acid-induced apoptosis of human sebaceous gland cells

13-cis retinoic acid (13-cis RA; also known as isotretinoin) is the most potent agent available for treatment of acne. It is known that the drug induces apoptosis in cells cultured from human sebaceous glands, but its mechanism of action has not been determined. In this study, skin biopsies were taken from 7 patients with acne prior to and at 1 week of treatment with 13-cis RA. TUNEL staining confirmed that 13-cis RA induced apoptosis in sebaceous glands. Transcriptional profiling of patient skin and cultured human sebaceous gland cells (SEB-1 sebocytes) indicated that lipocalin 2 was among the genes most highly upregulated by 13-cis RA. Lipocalin 2 encodes neutrophil gelatinase-associated lipocalin (NGAL), which functions in innate immune defense and induces apoptosis of murine B lymphocytes. Increased immunolocalization of NGAL was noted in patients' sebaceous glands following treatment with 13-cis RA, and recombinant NGAL induced apoptosis in SEB-1 sebocytes. Furthermore, apoptosis in response to 13-cis RA was inhibited in the presence of siRNA to lipocalin 2. These data indicate that NGAL mediates the apoptotic effect of 13-cis RA and suggest that agents that selectively induce NGAL expression in sebaceous glands might represent therapeutic alternatives to the use of 13-cis RA to treat individuals with acne.

In vivo long-term effects of retinoic acid exposure in utero on induced hyperplastic epidermal foci in murine skin

Adult Naval Medical Research Institute (NMRI) mice, after prenatal exposure to retinoic acid (RA), were treated with a standard two-stage skin carcinogenesis regime to characterize hyperplastic epidermal foci that precede the appearance of cutaneous papillomas, and to investigate the in vivo long-term action of RA on adult mouse skin treated with DMBA (7,12 dimethyl benz[a]anthracene) and TPA (12-O-tetradecanoylphorbol 13-acetate). The results demonstrate that RA administered to pregnant mice had a long-term inhibitory action on the cell differentiation and development of hyperplastic lesions occurring prior to cancer on the adult skin of their offspring as well as a stimulatory effect on cell proliferation of these hyperplastic lesions.

Case of acne conglobata successfully treated by CO2laser combined with topical tretinoin therapy

Acne conglobata is an uncommon disorder characterized by the presence of nodulocystic lesions. Conservative therapy with oral and topical antibiotics is of limited efficacy in many cases, and surgical excision is often needed for removal of the cystic lesions. Treatment is particularly difficult in cases with lesions located in aesthetically sensitive areas, such as the face. We successfully treated a case of acne conglobata by CO(2) laser ablation to remove the top of the sinuses and their tracts. In addition, topical tretinoin therapy was also initiated simultaneously to prevent the appearance of new acne lesions. Based on the results, we propose that the use of CO(2) laser for opening the cysts, combined with topical tretinoin therapy to prevent the appearance of new lesions, is a powerful treatment option for acne conglobata.

Systemic retinoid therapy: a status report on optimal use and safety of long-term therapy

Systemic retinoids are an important component of the dermatology treatment armamentarium offering unique therapeutic properties, and are widely used to treat a large spectrum of skin disorders. Rational selection of candidates for treatment, knowledge regarding appropriate and optimal use, awareness of common and uncommon potential adverse reactions, and proper use of clinical and laboratory monitoring can result in effective and safe treatment of several severe skin disorders that impact poorly on the overall health and quality of life of affected patients.

Comedolytic effect of topically applied active vitamin D3 analogue on pseudocomedones in the rhino mouse

BACKGROUND

Retinoids and active vitamin D(3) analogues regulate the proliferation and differentiation of keratinocytes and are effective in the treatment of psoriasis. Retinoids are known to be effective against acne vulgaris through comedolysis. However, the comedolytic effect of active vitamin D(3) analogues has not been reported.

OBJECTIVES

To investigate whether maxacalcitol, one of the active vitamin D(3) analogues, has a comedolytic effect by using spontaneously comedogenic rhino mice.

METHODS

Rhino mice were treated topically with tretinoin and maxacalcitol once daily for 2 and 4 weeks, respectively. The dermal side of the epidermal sheet was observed to determine the size of the utricle. Haematoxylin and eosin-stained vertical sections were used to measure utricle diameter and density and to evaluate histological changes.

RESULTS

Maxacalcitol (25 microg g(-1)) and tretinoin (0.1%) significantly decreased the size and the diameter of the utricle after 1 week of treatment. However, maxacalcitol did not affect the density while tretinoin did have an effect. Histopathologically, maxacalcitol and tretinoin markedly induced epidermal hyperplasia accompanied by a minor accumulation of inflammatory cells in the dermis, with and without hypercornification, respectively.

CONCLUSIONS

These results indicate that maxacalcitol has a prominent effect on comedolysis and that its mechanism of action may be different from that of retinoids.

Mouse epidermal development: effects of retinoic acid exposure in utero

Epidermal morphogenesis was studied in vivo following prenatal exposure to retinoic acid (RA). In pregnant mice, a single oral dose of RA on day 11.5 of gestation failed to induce histological changes in fetal epidermal development except in epidermal thickness. Epidermal thickness increased from 16.5 days post-coitum (dpc) onwards, and temporal and spatial epidermal modifications in keratins K5 and K14 related to proliferative activity of keratinocytes were observed. An RA effect on cell proliferation was supported by a statistically significant increase in the number of epidermal S-phase cells, containing BrdU-incorporated DNA in RA-exposed mice compared with nonexposed animals. The prolonged in utero action of RA on epidermal proliferative activity in fetuses and newborns suggests a long-term RA effect that may play a role on the development and evolution of diseases in adult skin.

Acne and active patients: improving more than superficial appearances

Acne vulgaris is a common skin condition that affects many athletes. Accurate diagnosis of the type and severity of acne lesions will help direct appropriate therapeutic interventions. Medications, including topical retinoids, topical antibiotics, oral antibiotics, and oral retinoids, are effective in treating acne. Side effects of acne therapy are common and generally mild, but athletes may require special counseling to minimize adverse effects of acne therapy. Treating acne may be challenging for both patient and physician, but with patience and perseverance, an appropriate treatment plan can provide dramatic improvements in the skin, emotional well-being, and social and athletic functioning.

Inflammation and extracellular matrix degradation mediated by activated transcription factors nuclear factor-kappaB and activator protein-1 in inflammatory acne lesions in vivo

Acne is the most common skin disease, causing significant psychosocial problems for those afflicted. Currently available agents for acne treatment, such as oral antibiotics and isotretinoin (Accutane), have limited use. Thus, development of novel agents to treat this disease is needed. However, the pathophysiology of acne inflammation is poorly understood. Before new therapeutic strategies can be devised, knowledge regarding molecular mechanisms of acne inflammation is required. We report here that transcription factors nuclear factor-kappaB and activator protein-1 are activated in acne lesions with consequent elevated expression of their target gene products, inflammatory cytokines and matrix-degrading metalloproteinases, respectively. These elevated gene products are molecular mediators of inflammation and collagen degradation in acne lesions in vivo. This new knowledge enables a rational strategy for development of pharmacological agents that can target the inflammation and matrix remodeling that occurs in severe acne.

Effect of a single course of isotretinoin therapy on bone mineral density in adolescent patients with severe, recalcitrant, nodular acne

BACKGROUND

Adverse changes in bone have been reported for patients undergoing high-dose, long-term (several years) isotretinoin therapy for disorders of cornification. The effect of short-term (4-5 months) therapy at the lower dose recommended for acne on bone development in younger, growing adolescent (12-17 years) patients has not been well studied.

OBJECTIVE

The purpose of the study was to evaluate the effect of a standard, single course of isotretinoin (Accutane) therapy on bone mineral density (BMD) of the lumbar spine and hip in adolescents ages 12 to 17 years with severe, recalcitrant, nodular acne.

METHODS

In this open-label, multicenter study, 217 adolescents (81 girls) with severe, recalcitrant, nodular acne were enrolled and treated with isotretinoin twice daily with food at the recommended total dose of approximately 1 mg/kg for 16 to 20 weeks. BMD in the lumbar spine and hip was measured at baseline and at the end of therapy by dual energy radiograph absorptiometry.

RESULTS

There was no clinically significant mean change in BMD measured at the lumbar spine (+1.4%, range: -4.9% to +12.3%) or total hip (-0.26%, range: -11.3% to +15.0%). Hyperostosis was not observed in any patient. Typical efficacy expected in the treatment of acne was observed.

CONCLUSIONS

A 16- to 20-week course of isotretinoin treatment at the recommended dose for severe acne has no clinically significant effect on lumbar spine and total hip BMD in the adolescent (12-17 years) population.

Potentiation of the teratogenic effects induced by coadministration of retinoic acid or phytanic acid/phytol with synthetic retinoid receptor ligands

Previous studies in our laboratory identified retinoid-induced defects that are mediated by RAR-RXR heterodimerization using interaction of synthetic ligands selective for the retinoid receptors RAR and RXR in mice (Elmazar et al. 1997, Toxicol Appl Pharmacol 146:21-28; Elmazar et al. 2001, Toxicol Appl Pharmacol 170:2-9; Nau and Elmazar 1999, Handbook of experimental pharmacology, vol 139, Retinoids, Springer-Verlag, pp 465-487). The present study was designed to investigate whether these RAR-RXR heterodimer-mediated defects can be also induced by interactions of natural and synthetic ligands for retinoid receptors. A non-teratogenic dose of the natural RXR agonist phytanic acid (100 mg/kg orally) or its precursor phytol (500 mg/kg orally) was coadministered with a synthetic RARalpha-agonist (Am580; 5 mg/kg orally) to NMRI mice on day 8.25 of gestation (GD8.25). Furthermore, a non-teratogenic dose of the synthetic RXR agonist LGD1069 (20 mg/kg orally) was also coadministered with the natural RAR agonist, all- trans-retinoic acid (atRA, 20 mg/kg orally) or its precursor retinol (ROH, 50 mg/kg orally) to NMRI mice on GD8.25. The teratogenic outcome was scored in day-18 fetuses. The incidence of Am580-induced resorptions, spina bifida aperta, micrognathia, anotia, kidney hypoplasia, dilated bladder, undescended testis, atresia ani, short and absent tail, fused ribs and fetal weight retardation were potentiated by coadministration of phytanic acid or its precursor phytol. Am580-induced exencephaly and cleft palate, which were not potentiated by coadministration with the synthetic RXR agonists, were also not potentiated by coadministration with either phytanic acid or its precursor phytol. LGD1069 potentiated atRA- and ROH-induced resorption, exencephaly, spina bifida, aperta, ear anotia and microtia, macroglossia, kidney hypoplasia, undescended testis, atresia ani, tail defects and fetal weight retardation, but not cleft palate. These results suggest that synergistic teratogenesis can be induced by coadministration of a natural RXR ligand (phytanic acid) with a synthetic RAR agonist (Am580). Thus, certain potentially useful therapeutic agents or nutritional factors such as phytanic acid should be tested for teratogenic risk by coadministration with other retinoid receptor agonists.

A comparison of the effectiveness of soy protein isolate and fish oil for reducing the severity of retinoid-induced hypertriglyceridemia

The effectiveness of soy protein isolate (SPI) to reduce the severity of retinoid-induced hypertriglyceridemia has been demonstrated in the rat, but not in human subjects. Because fish oil has been demonstrated to be effective at lowering serum triglyceride concentration in human subjects undergoing retinoid therapy, a study was conducted to compare the ability of SPI with that of fish oil to reduce the severity of retinoid-induced hypertriglyceridemia in the rat. Male Fischer 344 rats, n=8/group, were fed one of four isonitrogenous, isoenergetic diets, consisting of a control diet containing 24% casein +20% corn oil (C), and three 13-cis retinoic acid (13cRA)-supplemented diets containing 24% casein +20% corn oil (R), 24% SPI +20% corn oil (SR), and 24% casein +15% fish oil and 5% corn oil (FR). There was no effect of diet on food intake or final body weight. Serum triglyceride concentration for group R was higher (P<0.001) than for groups C, SR, and FR (7.20 vs. 2.50, 2.84, and 2.02 mmol/L, respectively); values for groups SR and FR did not differ for this parameter. The serum concentration of 13cRA for group R did not differ from that for groups SR and FR. Thus, SPI was as effective as fish oil in reducing the severity of retinoid-induced hypertriglyceridemia in an animal model, suggesting that it may be effective for this purpose in human subjects.

Topical acne drugs: review of clinical properties, systemic exposure, and safety

This review examines the commonly available topical acne agents and factors that determine their percutaneous absorption. Reported and theoretical adverse effects from systemic exposure are detailed. The topical retinoid class, which includes tretinoin, adapalene and tazarotene, and the topical antibacterials, clindamycin and erythromycin, are regulated by prescription in most countries. Used appropriately, the above-mentioned drugs deliver, at most, miniscule amounts of active ingredient into the circulation. Clear-cut links to systemic toxicity in humans are practically nonexistent, except in the case of topical clindamycin, which has been associated with diarrhea rarely, and there have been 2 cases of pseudomembranous colitis reported. Birth defects have occurred in two patients treated with tretinoin and one patient treated with adapalene, but causation was not proven. Another prescription drug, 20% azelaic acid, is associated with relatively high systemic exposure, which is presumed innocuous because it is a normal dietary constituent whose endogenous levels are not altered by topical use. Benzoyl peroxide, salicylic acid, sulfur, and sodium sulfacetamide are available in concentrations of 2% or more in over-the-counter acne treatments and some prescription products. All of these agents are known to exhibit some degree of percutaneous absorption. They remain largely unregulated because, other than skin irritation, only local allergic contact dermatitis from benzoyl peroxide in about 2.5% of patients and rare local and systemic hypersensitivity reactions from sodium sulfacetamide have been reported. Salicylism has occurred using methyl salicylate ointments and high concentrations of salicylic acid on widespread areas of hyperkeratotic skin, but there are no known cases resulting from salicylic acid acne products. Caution is advised in special circumstances, such as during childhood, pregnancy, lactation and concomitant therapy with other drugs, because relevant studies are lacking. Animal data support avoidance of many topical agents, particularly known teratogens such as retinoids and salicylic acid, in pregnant women. Salicylate avoidance is advised during lactation, because aspirin use carries the risk of bleeding disorders in nursing infants.

Changing paradigms in dermatology: nuclear hormone receptors

Nuclear hormone receptors (NHRs) are a family of proteins that function similarly as nuclear transcription factors. The NHR family includes glucocorticoid receptors, retinoic acid and retinoid receptors, vitamin D receptors, thyroxin receptors, and peroxisome proliferator activated receptors. These proteins are targets for some of the most commonly prescribed medications in dermatology, including corticosteroids, retinoids, and vitamin D analogues, all of which have limiting side effects. Advances in this field have led to better understanding of the mechanisms of NHR therapeutic and toxic effects, receptor subtypes, tissue distribution, and interaction with other molecules. New generations of more specific NHR ligands designed to increase therapeutic efficacy and limit adverse effects have dramatically expanded the clinical application of NHR-targeting drugs. The current understanding of NHRs and future directions for NHR ligands in dermatology are discussed.

Too much of a good thing: retinoic acid as an endogenous regulator of neural differentiation and exogenous teratogen

Retinoic acid (RA) is essential for both embryonic and adult growth, activating gene transcription via specific nuclear receptors. It is generated, via a retinaldehyde intermediate, from retinol (vitamin A). RA levels require precise regulation by controlled synthesis and catabolism, and when RA concentrations deviate from normal, in either direction, abnormal growth and development occurs. This review describes: (i) how the pattern of RA metabolic enzymes controls the actions of RA; and (ii) the type of abnormalities that result when this pattern breaks down. Examples are given of RA control of the anterior/posterior axis of the hindbrain, the dorsal/ventral axis of the spinal cord, as well as certain sex-specific segments of the spinal cord, using varied animal models including mouse, quail and mosquitofish. These functions are highly sensitive to abnormal changes in RA concentration. In rodents, the control of neural patterning and differentiation are disrupted when RA concentrations are lowered, whereas inappropriately high concentrations of RA result in abnormal development of cerebellum and hindbrain nuclei. The latter parallels the malformations seen in the human embryo exposed to RA due to treatment of the mother with the acne drug Accutane (13-cis RA) and, in cases where the child survives beyond birth, a particular set of behavioural anomalies can be described. Even the adult brain may be susceptible to an imbalance of RA, particularly the hippocampus. This report shows how the properties of RA as a neural induction agent and organizer of segmentation can explain the consequences of RA depletion and overexpression.

Oral retinoid therapy for dermatologic conditions in children and adolescents

The efficacy of systemic retinoid therapy in a number of dermatologic diseases is well established; however, concerns about potential side effects limit their use, especially in children. We review the efficacy and toxicity of oral retinoids in the pediatric population. The acute mucocutaneous toxicities commonly observed are typically well tolerated, readily treatable, and reversible. Systemic toxicities include teratogenicity and effects on the musculoskeletal, neurologic, and gastrointestinal systems. Children, like adults, generally tolerate short-term retinoid therapy without major complications. Concerns regarding serious systemic side effects are greater for those on high doses of oral synthetic retinoids for longer periods of time. Close patient monitoring and patient education can minimize the occurrence of complications. (J Am Acad Dermatol 2003;49:171-82.)Learning objective At the conclusion of this learning activity, participants should be familiar with use of oral retinoids for childhood dermatologic conditions such as psoriasis, acne, and ichthyoses as well as safety and risks associated with oral retinoid use in children and adolescents.

A critical period for retinoic acid teratogenesis and loss of neurophilic migration of pontine nuclei neurons

Abnormalities in the pontine nuclei (PN) and inferior olive are hallmarks of human retinoic acid (RA) teratogenesis. This study shows that RA exposure of the mouse at a specific embryonic stage alters morphological structures that derive from the wall of the IVth ventricle to form components of the precerebellar system (the inferior olivary nucleus and the PN). The study employs both normal and a RAREhspLacZ transgenic RA reporter mouse. It is shown that abnormalities in the PN and inferior olive result from exposure at a critical period of embryonic day 9.5 and 10.5. The abnormalities in the PN are due to a failure in their usual neurophilic migration. The compact stream of cells that leads from the anterior rhombic lip to the ventral pons is instead scattered widely over the anterior medulla. Given that the RA exposure occurs after the resolution of rhombomere identity this suggests that teratogenic RA interferes with a regulatory event that overlays this original pattern.

Glycerol regulates stratum corneum hydration in sebaceous gland deficient (asebia) mice

The only known function of human sebaceous glands is the provocation of acne. We assessed here whether sebum influences stratum corneum hydration or permeability barrier function in asebia J1 and 2 J mice, with profound sebaceous gland hypoplasia. Asebia J1 mice showed normal permeability barrier homeostasis and extracellular lamellar membrane structures, but they displayed epidermal hyperplasia, inflammation, and decreased (>50%) stratum corneum hydration, associated with a reduction in sebaceous gland lipids (wax diesters/monoesters, sterol esters). The triglyceride content of both asebia and control stratum corneum was low, consistent with high rates of triglyceride hydrolysis within the normal pilosebaceous apparatus, despite high rates of triglyceride synthesis. Although a mixture of synthetic, sebum-like lipids (sterol/wax esters, triglycerides) did not restore normal stratum corneum hydration to asebia skin, topical glycerol, the putative product of triglyceride hydrolysis in sebaceous glands, normalized stratum corneum hydration, and the glycerol content of asebia stratum corneum was 85% lower than in normal stratum corneum. In contrast, another potent endogenous humectant (urea) did not correct the abnormality. The importance of glycerol generation from triglyceride in sebaceous glands for stratum corneum hydration was demonstrated further by (i) the absence of sebaceous-gland-associated lipase activity in asebia mice, whereas abundant enzyme activity was present in the glands of control mice; and (ii) the inability of high concentrations of topical triglyceride to correct the hydration abnormality, despite the presence of abundant lipase activity in asebia stratum corneum. These results show that sebaceous-gland-derived glycerol is a major contributor to stratum corneum hydration.

Treatment with isotretinoin inhibits lipofuscin accumulation in a mouse model of recessive Stargardt's macular degeneration

Recessive Stargardt's macular degeneration is an inherited blinding disease of children caused by mutations in the ABCR gene. The primary pathologic defect in Stargardt's disease is accumulation of toxic lipofuscin pigments such as N-retinylidene-N-retinylethanolamine (A2E) in cells of the retinal pigment epithelium. This accumulation appears to be responsible for the photoreceptor death and severe visual loss in Stargardt's patients. Here, we tested a therapeutic strategy to inhibit lipofuscin accumulation in a mouse model of recessive Stargardt's disease. Isotretinoin (Accutane) has been shown to slow the synthesis of 11-cis-retinaldehyde and regeneration of rhodopsin by inhibiting 11-cis-retinol dehydrogenase in the visual cycle. Light activation of rhodopsin results in its release of all-trans-retinaldehyde, which constitutes the first reactant in A2E biosynthesis. Accordingly, we tested the effects of isotretinoin on lipofuscin accumulation in abcr(-/-) knockout mice. Isotretinoin blocked the formation of A2E biochemically and the accumulation of lipofuscin pigments by electron microscopy. We observed no significant visual loss in treated abcr(-/-) mice by electroretinography. Isotretinoin also blocked the slower, age-dependent accumulation of lipofuscin in wild-type mice. These results corroborate the proposed mechanism of A2E biogenesis. Further, they suggest that treatment with isotretinoin may inhibit lipofuscin accumulation and thus delay the onset of visual loss in Stargardt's patients. Finally, the results suggest that isotretinoin may be an effective treatment for other forms of retinal or macular degeneration associated with lipofuscin accumulation.

Selective photothermolysis of the sebaceous glands for acne treatment

BACKGROUND AND OBJECTIVES

The purpose of this study is to evaluate the efficacy of a long pulse diode laser (Cynosure, Inc.) to target and destroy enlarged sebaceous glands that are preloaded with Indocyanine green (ICG) chromophore.

STUDY DESIGN/MATERIALS AND METHODS

This study was designed in three phases. First, preliminary studies were performed to determine the ability of ICG to penetrate into enlarged sebaceous glands. Once penetration of the sebaceous gland was confirmed, the second phase was to determine the necessary parameters for the diode laser to effectively target the ICG loaded glands. This was done using laser-tissue interaction analysis. The final phase was done with patients that had active acne on their back to determine if selective destruction of the sebaceous glands could be achieved and also to assess the safety and efficacy of this novel treatment for acne.

RESULTS

Fluorescence microscopy of biopsy samples show evidence of ICG penetration into the sebaceous glands. Histological examination of biopsy samples from the treated areas finds selective necrosis of the sebaceous glands. Preliminary clinical results demonstrate a decrease in acne noted in the treatment area at 3, 6, and 10 months follow-up.

CONCLUSIONS

ICG and diode laser treatment is a new approach for the treatment of acne based on experimentally observed selective photothermolysis of the sebaceous glands.

Effects of in utero retinoic acid exposure on mouse pelage hair follicle development

We investigated in vivo the histological and immunohistochemical responses of mouse hair pelage follicle morphogenesis to prenatal exposure to a potentially nonteratogenic dose of all-trans-retinoic acid (RA), as a basis studying the preventive effect of RA on adult mouse skin carcinogenesis. In pregnant mice, a single oral dose of RA at 30 mg kg-1 body weight given on day 11.5 of gestation caused no RA-induced changes in the morphology or temporal expression patterns of keratins during pelage hair follicle morphogenesis. The only differential effect of RA was a statistically significant increase in the number of BrdU-positive nuclei in hair bulbs from RA exposed fetuses compared with nonexposed mice. The absence of adverse RA effects suggests that this experimental design may represent a valuable protocol for use in studies on the in vivo effects of this retinoid on different skin diseases.

Complex disease and the new clinical sciences

Medical research today is dominated by a genocentric point of view. At the same time, clinical discovery and patient-oriented research have become less common. Here, I suggest that these developments are interdependent, each representing the flip side of an inaccurate view of how clinical advance occurs.

Safety issues in isotretinoin therapy

Isotretinoin (Accutane, Roche Laboratories Inc, Nutley, NJ) is an important drug, not only for the treatment of severe acne, but also for other diagnoses and in chemoprevention settings. Because the use of isotretinoin is increasing, it is important for physicians to be aware of the adverse events, toxicities, and management issues related to its use. The most important issue is that of congenital defects, which has resulted in new pregnancy prevention policies and programs implemented by the manufacturer. A relatively new concern is that of depression associated with isotretinoin use, also resulting in new policies placed by the manufacturer and the FDA. The most common adverse effects observed during treatment are mucocutaneous and ocular in nature, but laboratory abnormalities and effects in the nervous, musculoskeletal, gastrointestinal, pulmonary, hematologic, and other systems are also described. Additionally, potential drug interactions, follow-up, and toxicity prevention measures are discussed.

Developments in topical retinoid therapy for acne

Topical retinoic acid was introduced for acne treatment three decades ago. Since that time, researchers have discovered thousands of retinoids, originally defined as chemical analogs of vitamin A. After the identification of nuclear retinoid receptors in 1987, the definition of this class expanded to include molecules that bind to and activate such receptors. The receptor-selective retinoid agents, adapalene and tazarotene, were developed in the 1990s. Other innovations of the past decade include retinoid formulations and methods aimed at limiting retinoid absorption. Cutaneous irritation may be reduced without losing retinoid efficacy by inhibiting retinoid penetration into the deep epidermis and dermis. Examples include tretinoin in slow-release vehicles and the short-contact method of tazarotene gel therapy. Only trace amounts of adapalene are absorbed after topical application, perhaps explaining its relatively low irritancy. New formulations of existing agents, such as additional concentrations of tretinoin in microsphere gel and cream formulations of tazarotene, are now under investigation for acne. Current research focused on receptor selectivity holds the promise of yielding new retinoid molecules with improved benefits and safety.