Side effects of systemic retinoids and their clinical management

Electric neurostimulation regulates microglial activation via retinoic acid receptor α signaling

Brain stimulation by electroconvulsive therapy is effective in neuropsychiatric disorders by unknown mechanisms. Microglial toxicity plays key role in neuropsychiatric, neuroinflammatory and degenerative diseases. We examined the mechanism by which electroconvulsive seizures (ECS) regulates microglial phenotype and response to stimuli. Microglial responses were examined by morphological analysis, Iba1 and cytokine expression. ECS did not affect resting microglial phenotype or morphology but regulated their activation by Lipopolysaccharide stimulation. Microglia were isolated after ECS or sham sessions in naïve mice for transcriptome analysis. RNA sequencing identified 141 differentially expressed genes. ECS modulated multiple immune-associated gene families and attenuated neurotoxicity-associated gene expression. Blood brain barrier was examined by injecting Biocytin-TMR tracer. There was no breakdown of the BBB, nor increase in gene-signature of peripheral monocytes, suggesting that ECS effect is mainly on resident microglia. Unbiased analysis of regulatory sequences identified the induction of microglial retinoic acid receptor α (RARα) gene expression and a putative common RARα-binding motif in multiple ECS-upregulated genes. The effects of AM580, a selective RARα agonist on microglial response to LPS was examined in vitro. AM580 prevented LPS-induced cytokine expression and reactive oxygen species production. Chronic murine experimental autoimmune encephalomyelitis (EAE) was utilized to confirm the role RARα signaling as mediator of ECS-induced transcriptional pathway in regulating microglial toxicity. Continuous intracerebroventricular delivery of AM580 attenuated effectively EAE severity. In conclusion, ECS regulates CNS innate immune system responses by activating microglial retinoic acid receptor α pathway, signifying a novel therapeutic approach for chronic neuroinflammatory, neuropsychiatric and neurodegenerative diseases.

Synthesis of Retinol-Loaded Lipid Nanocarrier via Vacuum Emulsification to Improve Topical Skin Delivery

Retinol has been widely used as an anti-wrinkle active ingredient in cosmetic fields. However, the oxidation of retinol by air was one of the critical problems for application in the skincare field. In this study, Retinol-loaded lipid nanocarriers were prepared via the vacuum emulsification method to increase the stability of retinol vulnerable to air and optimized encapsulation conditions and to increase the penetration efficiency into skin. Optimizing the components of lipid nanocarriers, gradients of carbon chain C8-22 using various lipid species which made the amorphous structure and enough spaces to load retinol inside the capsules were estimated from the lower enthalpy change and peak shift in DSC analysis. The vacuum-assisted lipid nanocarriers (VLN) could help suppress oxidation, which could have advantages to increase the thermal stability of retinol. The retinol-loaded VLN (VLN-ROL) had narrow size distribution under 0.3 PDI value, under 200 nm scaled particle size, and fully negative surface charge of about -50 mV for the electrostatic repulsion to avoid aggregation phenomenon among the lipid nanoparticles. It maintained 90% or more retinol concentration after 4 weeks of storage at 25, 40 and 50 °C and kept stable. The VLN-ROL-containing cream showed improved penetration efficiency applied to porcine skins compared to the commercial retinol 10S from BASF. The total amount of retinol into the skin of VLN-ROL (0.1% of retinol) was enhanced by about 2.2-fold (2.86 ± 0.23 μg) higher than that in 0.1% of bare retinol (about 1.29 ± 0.09 μg). In addition, applied on a 3D Human skin model, the epidermal thickness and the relative percentage of dermal collagen area effectively increased compared to the control and retinol, respectively. Additionally, the level of secreted IL-1α was lower and epidermal damage was weaker than commercial product A. This retinol-loaded lipid nanocarrier could be a potentially superior material for cosmetics and biomedical research.

Effect of Serum 25 Hydroxy Vitamin D Level on Isotretinoin-Induced Musculoskeletal Symptoms: A Cross-Sectional Study

Isotretinoin (ISO) is a drug which is used for the treatment of severe and refractory acne vulgaris (AV), over the last few decades. The drug has various musculoskeletal side effects. The aim of this study was to investigate relationship between serum 25 hydroxy (OH) vitamin D levels and the ISO-induced musculoskeletal side effects in patients with AV. We included 87 patients receiving ISO and had musculoskeletal symptoms as adverse effect (AE) group. Another 90 patients receiving ISO for AV and had any musculoskeletal complaints were recruited as control (C) group. Locomotor system examination of the patients was performed by the same clinician. Serum 25 OH vitamin D levels of the all participants were measured. Patients in the AE group were divided into three subgroups by serum 25 OH vitamin D levels. Patients with serum 25 OH vitamin D level lower than 10 ng/ml was classified as Group I, the ones between 10-20 ng/ml as Group II and those higher than 20 ng/ml were classified as Group III. AE and C groups were similar in terms of age and sex (p > 0.05). There was no statistically significant difference in the mean serum vitamin D levels between two groups (p = 0.17). Also, there was no significant difference in number of arthralgia (p = 0.30), myalgia (p = 0.29), low back pain (p = 0.10) and sacroiliitis (p = 0.17) between three subgroups in AE group. In addition, we found no statistically significant correlation between the serum vitamin D levels and age, cumulative dose of ISO, arthralgia, myalgia and sacroiliitis parameters in AE group (p > 0.05). Serum 25 OH vitamin D levels between the AE and C groups were similar. We also found that no significant difference in musculoskeletal adverse events between AE subgroups. Therefore, it can be concluded that vitamin D deficiency has no effect on the musculoskeletal adverse events in patients receiving ISO.

All-trans retinoic acid eluting poly(diol citrate) wafers for treatment of glioblastoma

Current treatments for glioblastoma have failed to significantly increase patient survival, are extremely cytotoxic, can cause severe side effects, and are ineffective. Given these limitations, drugs other than cytotoxic chemotherapeutic agents are being explored. Recent studies show that all-trans retinoic acid (ATRA) could be effective on cancer cells as they have been shown to suppress carcinogenesis in a variety of tumor types and can reverse premalignant lesions and inhibit the development of secondary tumors in the head and neck of cancer patients. However, the therapeutic effects of retinoids such as ATRA are undermined by its rapid in vivo metabolism by cytochrome P450 enzymes, difficulty in crossing the blood-brain barrier, and sensitivity to isomerization/degradation. To overcome these limitations, we have developed a porous poly(1,8-octanediol-co-citrate; POC) wafer that stabilizes all-trans retinoic acid, while slowly releasing ATRA over 3 months. Release of ATRA from POC wafers inhibited proliferation of U87MG (glioblastoma) cells and caused upregulation in genes associated with differentiation into normal phenotype and apoptosis. Therefore, ATRA eluting poly(diol citrate) wafers are a promising treatment option compared to traditional cytotoxic chemotherapeutic agents.

Increasing the percutaneous absorption and follicular penetration of retinal by topical application of proretinal nanoparticles

Topical retinoids are frequently applied for therapeutic and cosmeceutical reasons although their bioavailability is low due to their chemical and photochemical instability. Moreover, skin irritation is a common side effect. Therefore, proretinal nanoparticles (PRN) as a novel formulation of topical retinoids, which are based on chitosan grafted with retinal through reversible linkage, were developed and their skin penetration behavior was studied. As nanoparticles preferably penetrate into the hair follicles, the follicular penetration depths of PRN at different time points were investigated. Moreover, the release capacity of the nanoparticulate system was studied using fluorescein as a model drug. Additionally, the concentration of retinal in the stratum corneum and in the hair follicles was quantified after application in particulate and non-particulate form. The results showed that the nanocarriers reached the infundibular area of the hair follicles, irrespective of the incubation time. The nanoparticles were able to release their model drug within the hair follicle. The retinal concentration delivered to the stratum corneum and the hair follicles was significantly higher when retinal was applied in the particulate form. In conclusion, the presented proretinal nanoparticle system may help to overcome the main problems of topical retinoid therapy, which are skin irritation, chemical and photochemical instability and low bioavailability, thus improving the topical retinoid therapy.

Chemoprevention agents for melanoma: A path forward into phase 3 clinical trials

Recent progress in the treatment of advanced melanoma has led to unprecedented improvements in overall survival and, as these new melanoma treatments have been developed and deployed in the clinic, much has been learned about the natural history of the disease. Now is the time to apply that knowledge toward the design and clinical evaluation of new chemoprevention agents. Melanoma chemoprevention has the potential to reduce dramatically both the morbidity and the high costs associated with treating patients who have metastatic disease. In this work, scientific and clinical melanoma experts from the national Melanoma Prevention Working Group, composed of National Cancer Trials Network investigators, discuss research aimed at discovering and developing (or repurposing) drugs and natural products for the prevention of melanoma and propose an updated pipeline for translating the most promising agents into the clinic. The mechanism of action, preclinical data, epidemiological evidence, and results from available clinical trials are discussed for each class of compounds. Selected keratinocyte carcinoma chemoprevention studies also are considered, and a rationale for their inclusion is presented. These data are summarized in a table that lists the type and level of evidence available for each class of agents. Also included in the discussion is an assessment of additional research necessary and the likelihood that a given compound may be a suitable candidate for a phase 3 clinical trial within the next 5 years.

Ichthyosis molecular fingerprinting shows profound TH17 skewing and a unique barrier genomic signature

BACKGROUND

Ichthyoses are a group of rare skin disorders lacking effective treatments. Although genetic mutations are progressively delineated, comprehensive molecular phenotyping of ichthyotic skin could suggest much-needed pathogenesis-based therapy.

OBJECTIVE

We sought to profile the molecular fingerprint of the most common orphan ichthyoses.

METHODS

Gene, protein, and serum studies were performed on skin and blood samples from 29 patients (congenital ichthyosiform erythroderma, n = 9; lamellar ichthyosis, n = 8; epidermolytic ichthyosis, n = 8; and Netherton syndrome, n = 4), as well as age-matched healthy control subjects (n = 14), patients with psoriasis (n = 30), and patients with atopic dermatitis (AD; n = 16).

RESULTS

Using criteria of a fold change of greater than 2 and a false discovery rate of less than 0.05, 132 differentially expressed genes were shared commonly among all ichthyoses, including many IL-17 and TNF-α-coregulated genes, which are considered hallmarks of psoriasis (defensin beta 4A, kynureninase, and vanin 3). Although striking upregulation of TH17 pathway genes (IL17F and IL36B/G) resembling that seen in patients with psoriasis was common to all patients with ichthyoses in a severity-related manner, patients with Netherton syndrome showed the greatest T-cell activation (inducible costimulator [ICOS]) and a broader immune phenotype with T_H1/IFN-γ, OASL, and T_H2/IL-4 receptor/IL-5 skewing, although less than seen in patients with AD (all P < .05). Ichthyoses lacked the epidermal differentiation and tight junction alterations of patients with AD (loricrin, filaggrin, and claudin 1) but showed characteristic alterations in lipid metabolism genes (ELOVL fatty acid elongase 3 and galanin), with parallel reductions in extracellular lipids and corneocyte compaction in all ichthyoses except epidermolytic ichthyosis, suggesting phenotypic variations. Transepidermal water loss, a functional barrier measure, significantly correlated with IL-17-regulated gene expression (IL17F and IL36A/IL36B/IL36G).

CONCLUSION

Similar to patients with AD and psoriasis, in whom cytokine dysregulation and barrier impairment orchestrate disease phenotypes, psoriasis-like immune dysregulation and lipid alterations characterize the ichthyoses. These data support the testing of IL-17/IL-36-targeted therapeutics for patients with ichthyosis similar to those used in patients with psoriasis.

Regulated differentiation of WERI-Rb-1 cells into retinal neuron-like cells

The encouraging response and improved survival of acute promyelocytic leukemia patients following retinoic acid treatment has rendered differentiation therapy an attractive option in cancer treatment. Given that terminal differentiation represents a considerable barrier in retinoblastoma tumorigenesis and that retinoblastoma has a significantly higher spontaneous degeneration rate compared with other tumors (1,000-fold change), differentiation therapy represents a promising alternative in the treatment of retinoblastoma. However, the full differentiation potential of retinoblastoma still unknown. The present study was designed to investigate the extend differentiation of the classical retinoblastoma cell line WERI-Rb-1 (W-RBCs). Several critical cell signaling pathways and key genes related to cell proliferation and differentiation were comprehensively regulated to control the fate of W-RBCs. Various strategies were applied to optimize simple and time-saving methods to induce W-RBCs into different types of retinal neuron-like cells (RNLCs) in vitro. Further, the tumorigenesis of these differentiated W-RBCs was tested in nude mice in vivo. W-RBCs were found to inherently express both retinal progenitor cell- and embryonic stem cell-related genes or proteins. Moreover, the addition of antagonists of critical cell signals (Wnt, Nodal, BMP4 and Notch), even without atonal bHLH transcription factor 7 gene transfection, could directly induce W-RBCs into RNLCs, and especially into photoreceptor-like and retinal ganglion-like cells. Interestingly, the differentiated cells showed remarkably poorer tumorigenesis in vivo. These findings may offer new insights on the oriented differentiation of W-RBCs into RNLCs with low tumorigenicity and provide potential targets for retinoblastoma differentiation therapy.

A new therapeutic for the treatment of moderate-to-severe plaque psoriasis: apremilast

Psoriasis is a common, chronic, inflammatory skin disease. Being a life-long condition, a prolonged and safe control of the disease is needed. Current anti-psoriatic treatments show some limits in terms of tolerability and route of administration. Recently, a new oral small molecule, apremilast, has been approved for the treatment of patients with moderate-to-severe plaque psoriasis. Apremilast is a phosphodiesterase 4 (PDE4) inhibitor that regulates the transduction of intracellular signals, including pro-inflammatory and anti-inflammatory pathways. Because of the favorable safety profile and the oral route of administration, apremilast may represent a promising therapeutic target for moderate-to-severe psoriasis. In this review, we report an updated overview about clinical trials testing apremilast in the treatment of psoriasis and seek to provide comprehensive information about this anti-psoriatic drug and a future perspective of the therapeutic algorithm for psoriasis.

Acitretin

Background:

Hidradenitis suppurativa (HS) is a chronic, recurrent inflammatory disease of the pilosebaceous follicle that severely affects patients’ quality of life and can be challenging for clinicians to manage. A few case series have reported on the efficacy of acitretin monotherapy in the treatment of intractable HS.

Objective:

To assess the efficacy of acitretin for the treatment of intractable HS.

Methods:

A retrospective review was conducted involving all patients with HS who received acitretin between January 2011 and January 2015 in a tertiary academic medical center. All patients with HS who received acitretin, either as a monotherapy or as an adjuvant to other systemic medications, were included, and clinical response was assessed using the physician global scale.

Results:

Fourteen patients with HS (mean age 48 years [range 32-64 years]; 9 [64%] were men) received acitretin. Most patients (86%) had Hurley stage II or III disease. All patients had failed other standard systemic medications prior to initiating acitretin. Six patients (43%) received acitretin monotherapy, and 8 patients (57%) received acitretin as an adjuvant to other standard systemic medications. None of the patients who received acitretin monotherapy exhibited clinical improvements. Clinical improvements were observed in 7 of the 8 (87.5%) patients who received acitretin as an adjuvant to other systemic medications, with 3 patients (37.5%) exhibiting partial response and 4 patients (50%) exhibiting good response.

Conclusions and Relevance:

Acitretin monotherapy was ineffective for the treatment of intractable HS. Acitretin may be effective when used as an adjuvant to other systemic medications.

Isotretinoin therapy and depression – evidence for an association

Objectives: The object of this paper is to evaluate the evidence suggesting an association between the use of the anti-acne agent isotretinoin and the subsequent development of depression.

Method: Three case histories of individuals who had received treatment with isotretinoin and subsequently developed depression are reviewed.

Results: All three individuals were noted to have a depressive illness which was notable by the prominence of symptoms of irritability, agitation and aggression.

Conclusions: The indications from the three cases described suggest that there appears to be an association between depression and the recent use of isotretinoin. This may relate to the ability of isotretinoin to simulate hypovitaminosis A, with aggression, irritability and depression as a direct result of this effect. Young males may be particularly prone to developing this response.

Soybean extract showed modulation of retinoic acid-related gene expression of skin and photo-protective effects in keratinocytes

Soy extracts are well known as medicinal and nutritional ingredients, and exhibit benefits towards human skin including depigmenting or anti-ageing effects. Despite the wrinkle decreasing effects of retinoids on skin as an anti-ageing ingredient, retinoid application can causes photo-sensitive responses such as skin irritation. Thus, their daytime usage is not recommended. The aim of this study is the investigation into the activities of soybean extract as an anti-ageing ingredient and their comparison to retinoids in this respect. Soybean extract decreased the relative ratio of MMP-1/TIMP-1 mRNA to the same degree as retinoic acid in normal human fibroblasts. It also affected mRNA levels of HAS2 and CRABP2 in normal human keratinocytes. Furthermore, we investigated its effect on mRNA expression of histidase, an enzyme that converts histidine into urocanic acid, the main UV light absorption factor of the stratum corneum. Unlike the complete inhibition of histidase exhibited by the mRNA expression of retinoic acid, the effect of soybean extract on histidase gene expression was weaker in normal human keratinocytes. Also, soybean extract pretreatment inhibited UVB-induced cyclobutane pyrimidine dimer formation dose-dependently in normal human keratinocytes. In this study, we found that soybean extract modulated retinoic acid-related genes and showed photo-protective effects. Our findings suggest that soybean extract could be an anti-ageing ingredient that can be safely used under the sunlight.

Combination antiretroviral therapy and chronic HIV infection affect serum retinoid concentrations: longitudinal and cross-sectional assessments

Background

Several lines of evidence suggest that retinoids (retinol-ROL or vitamin A, and its active metabolites, retinoic acids-RAs) play important pathogenic roles in HIV infection and combination antiretroviral therapy (cART)-related events. We previously reported that antiretrovirals alter RAs synthesis in vitro. We hypothesised that in vivo serum retinoid concentrations are affected by both cART and HIV infection. This might explain several clinical and laboratory abnormalities reported in HIV-infected patients receiving cART.

Methods

The effects of optimal cART and chronic HIV on serum retinoids were firstly assessed longitudinally in 10 HIV-infected adults (group1 = G1): twice while on optimal cART (first, during long-term and second, during short term cART) and twice during 2 cART interruptions when HIV viral load (VL) was detectable. Retinoid concentrations during optimal long term cART in G1 were compared with cross-sectional results from 12 patients (G2) with suboptimal cART (detectable VL) and from 28 healthy adults (G3). Serum retinoids were measured by HPLC with ultraviolet detection. Retinoid concentrations were correlated with VL, CD4⁺ T- cell count and percentages, CD8⁺38⁺ fluorescence, triglycerides, cholesterol and C-peptide serum levels.

Results

During optimal cART, G1 participants had drastically reduced RAs (0.5 ± 0.3 μg/dL; P < 0.01) but the highest ROL (82 ± 3.0 μg/dL) concentrations. During cART interruptions in these patients, RAs slightly increased whereas ROL levels diminished significantly (P < 0.05). G3 had the highest RAs levels (7.2 ± 1.1 μg/dL) and serum ROL comparable to values in North Americans. Serum ROL was decreased in G2 (37.7 ± 3.2 μg/dL; P < 0.01). No correlations were noted between RA and ROL levels or between retinoid concentrations and CD4⁺ T- cell count, CD8⁺38⁺ fluorescence, VL. ROL correlated with triglycerides and cholesterol in G1 (r_s = 0.8; P = 0.01).

Conclusions

Serum RAs levels are significantly diminished by cART, whereas ROL concentrations significantly decreased during uncontrolled HIV infection but augmented with optimal cART. These alterations in retinoid concentrations may affect the expression of retinoid-responsive genes involved in metabolic, hormonal and immune processes and be responsible for some adverse events observed in HIV-infected persons treated with antiretrovirals. Further studies should assess concomitant serum and intracellular retinoid levels in different clinical situations in larger, homogenous populations.

Alstonia scholaris R. Br. Significantly Inhibits Retinoid-Induced Skin Irritation In Vitro and In Vivo

Topical retinoids inhibit matrix metalloproteinases and accelerate collagen synthesis, thereby triggering antiaging effects in the skin. However, topical retinoids can cause severe skin reactions, including scaling, erythema, papules, and inflammation. The present study demonstrates that the ethanolic bark extract of Alstonia scholaris R. Br. can significantly inhibit all-trans retinoic acid-induced inflammation in human HaCat keratinocyte cells. Furthermore, two representative retinoid-induced proinflammatory cytokines, monocyte chemoattractant protein-1 and interleukin-8, were significantly suppressed by A. scholaris extract (by 82.1% and 26.3% at 100 ppm, and dose-dependently across the tested concentrations) in vitro. In a cumulative irritation patch test, A. scholaris extract decreased retinol-induced skin irritation, while strengthening the ability of retinoids to inhibit matrix metalloproteinase-1 expression, which is strongly associated with aging effects. These results suggest that A. scholaris is a promising compound that may increase the antiaging function of retinoids while reducing their ability to cause skin irritation.

Pregnancy outcome of women transfused during pregnancy with blood products inadvertently obtained from donors treated with acitretin

We assessed the pregnancy outcome of nine women inadvertently transfused with acitretin-contaminated blood products in South Korea. A total of 18 women matched to cases by age, gravidity, and singleton- or twin-pregnancy, and who were transfused with blood products not contaminated with acitretin, was also recruited. There were nine babies born in the case group. No differences (p > 0.05) were observed between cases and controls in the gestational age at delivery (38.3 +/- 1.6 weeks vs 37.8 +/- 2.2 weeks), birth weight (3,146 +/- 874 g vs 3,106 +/- 568 g), rate of pre-term deliveries (22.2% vs 11.1%) and rate of low birth weight (<2,500 g) (33.3% vs 16.7%). There was no case of malformation or neurological abnormalities born in either group. In conclusion, inadvertent exposure to acitretin-contaminated blood products was not associated with adverse pregnancy outcomes, probably because of the removal of acitretin and etretinate during the manufacturing process of blood products.

Anterior Segment and External Ocular Disorders Associated with Human Immunodeficiency Virus Disease

The eye is a common site for complications of human immunodeficiency virus (HIV) infection. Although cytomegalovirus retinitis remains the most prevalent of the blinding ocular disorders that can occur in individuals with the acquired immunodeficiency syndrome (AIDS), several important HIV-associated disorders may involve the anterior segment, ocular surface, and adnexae. Some of these entities, such as Kaposi sarcoma, were well described, but uncommon, before the HIV epidemic. Others, like microsporidial keratoconjunctivitis, have presentations that differ between affected individuals with HIV disease and those from the general population who are immunocompetent. The treatment of many of these diseases is challenging because of host immunodeficiency. Survival after the diagnosis of AIDS has increased among individuals with HIV disease because of more effective antiretroviral therapies and improved prophylaxis against, and treatment of, opportunistic infections. This longer survival may lead to an increased prevalence of anterior segment and external ocular disorders. In addition, the evaluation and management of disorders such as blepharitis and dry eye, which were previously overshadowed by more severe, blinding disorders, may demand increased attention, as the general health of this population improves. Not all individuals infected with HIV receive potent antiretroviral therapy, however, because of socioeconomic or other factors, and others will be intolerant of these drugs or experience drug failure. Ophthalmologists must, therefore, still be aware of the ocular findings that develop in the setting of severe immunosuppression. This article reviews the spectrum of HIV-associated anterior segment and external ocular disorders, with recommendations for their evaluation and management.

Isotretinoin in the treatment of multiple benign pilomatrixomas in a mixed-breed dog

An 18-month-old cross-breed dog developed multiple skin nodules, which over 8 months had increased in size and number. Biopsy samples were submitted for histopathological examination and revealed multiple benign pilomatrixomas. The dog was treated with 1 mg kg(-1) isotretinoin daily, which led to a stabilization of the size and number of the lesions. Attempts to lower the dosage to an every other day regimen led to an increase in the nodules' size and number. Monthly complete blood count and chemistry tests and Schirmer tear tests were performed to monitor any adverse effects of the retinoid treatment. No adverse effects were noted. To the authors' knowledge, this is the first report of multiple pilomatrixomas arising in a young dog and successfully controlled with oral retinoids.

Vitamin E does not reduce the side-effects of isotretinoin in the treatment of acne vulgaris

BACKGROUND

Isotretinoin is widely used in the treatment of severe, recalcitrant, nodular acne. Mucocutaneous side-effects are seen in the great majority of patients and some of them have elevations in their serum lipid and liver enzyme profiles. Recently, it has been shown that addition of vitamin E decreased the toxicity of high-dose retinoids.

OBJECTIVE

The purpose of this investigator-blinded, randomized study was to assess whether vitamin E would reduce the side-effects of isotretinoin in the treatment of acne vulgaris.

METHODS

Eighty two patients were randomly assigned to one of two treatment groups with isotretinoin (1 mg/kg/day) alone or combined with vitamin E (800 IU/day). The treatment duration was 16 weeks. Mucocutaneous side-effects such as facial erythema, facial dryness, cheilitis and serum lipid and liver enzyme profiles were assessed.

RESULTS

There was no difference in the incidence and severity of side-effects related to isotretinoin between the two treatment groups.

CONCLUSION

Eight hundred IU/day vitamin E did not improve the side-effects of 1 mg/kg/day of isotretinoin in the treatment of acne vulgaris.

Combination therapy to treat moderate to severe psoriasis

In patients with moderate-to-severe psoriasis, remission can be difficult to achieve and sustain. Both acutely acting and long-term maintenance agents are needed. Speed and efficiency of available monotherapies tend to be inversely proportional to safety. Combination, rotational, and sequential approaches are often more effective and safer than single-agent therapy. Combining agents with complementary adverse effect profiles is preferable. Apparent synergistic enhancement is seen with most paired combinations of the four major therapies: acitretin, phototherapy (ultraviolet B/psoralen plus ultraviolet A), cyclosporine, and methotrexate. Of those, only cyclosporine in combination with psoralen plus ultraviolet A is contraindicated because of increased cancer risk. Combinations of each of those major therapies with topical agents (retinoids, steroids, vitamin D derivatives, and others) have been used with varying efficacy and safety. The immunomodulators, hydroxyurea and thioguanine, have also shown some success in combination therapy. The new biologic agents with their novel modes of action and adverse effect profiles may prove to be important adjuncts in combination/rotational/sequential approaches. In some cases, monotherapy (with either systemic agents or phototherapy) adequately controls moderate to severe disease. A regimen using a single agent has the advantages of lower cost and greater adherence by the patient. For any number of reasons, however, including loss of efficacy, adverse effects, or cumulative or acute toxicity-and especially the inability to clear resistant lesions-a single modality will not be adequate. Using two or more therapies is thus the rule rather than the exception for most patients with moderate-to-severe psoriasis, but picking a combination that serves to balance safety and efficacy needs careful consideration, especially since no evidence-based treatment guidelines exist.

The efficacy of calcipotriol + acitretin combination therapy for psoriasis: comparison with acitretin monotherapy

BACKGROUND

Although the use of an oral retinoid as monotherapy is an effective treatment for psoriasis, it is usually used in combination with other topical or systemic therapies including topical corticosteroids, UVB phototherapy, psoralens + UVA (PUVA) chemotherapy and cyclosporine mainly in an effort to reduce or avoid adverse effects.

AIM

To compare the efficacy of the calcipotriol + acitretin combination treatment with acitretin alone over a long period in Korean patients with psoriasis.

METHODS

A randomized, bilateral paired comparison was conducted involving 40 patients with psoriasis who received calcipotriol + acitretin combination therapy and 20 psoriasis patients who received acitretin alone. The initial dose of acitretin was 10 or 20 mg/day. The dose was adjusted at each visit (2, 4 and 6 weeks) in steps of 10mg according to patient responsiveness and adverse effects. The maximum dose was 40 mg/day. The treatment duration for all patients ranged from 4-52 weeks. After 12 weeks, the efficacy of therapy, according to Psoriasis Area and Severity Index scores, was assessed. At the end of the study (52 weeks), we selected patients who had achieved complete clearance and compared the duration of treatment and total dose of acitretin used in both groups.

RESULTS

After 12 weeks, 16 patients (40%) achieved complete clearance in the calcipotriol + acitretin group and 3 patients (15%) in the acitretin monotherapy group (p < 0.05). After 52 weeks, 24 patients (60%) in the calcipotriol + acitretin group and 8 patients (40%) in the acitretin monotherapy group achieved complete clearance. The duration of treatment and total dose of retinoid required to achieve clearance were slightly lower in the calcipotriol + acitretin combination group, however, this was not statistically significant. With the exception of liver enzyme elevation (which affected more patients in the acitretin monotherapy group than in the combination group), adverse effects were not significantly different.

DISCUSSION

Our results showed that calcipotriol might enhance the clinical outcome of systemic acitretin therapy. More large, well-controlled, long-term studies need to be conducted to determine whether there is indeed a beneficial effect of the addition of calcipotriol to acitretin treatment and whether this effect is maintained over long-term periods.

The use of retinoids in the prevention and treatment of skin cancer

There has been a significant increase in the number of cases of skin cancer diagnosed in the US in the past few years. Thus, it seems appropriate to review the available compounds that might be used in the chemoprevention of these lesions. This review focuses on the retinoids and details their results in clinical trials for treatment and prevention of skin cancer. Side effects of the various retinoid derivatives are also discussed. It is concluded that isotretinoin (13-cis-retinoic acid) is the most effective retinoid for the prevention of non-melanoma skin cancers in high-risk patients in clinical trials. Current basic research is focused on developing receptor-selective retinoids which would have a higher therapeutic index for the treatment and chemoprevention of skin cancer.

HIV-protease inhibitors alter retinoic acid synthesis

BACKGROUND

An increasing rate of highly-active antiretroviral therapy (HAART)-associated metabolic and morphological abnormalities has been reported in HIV-infected persons. Some of them resemble retinoid-related adverse events, indicating alteration(s) of retinol metabolism or of retinoic acid-mediated signalling.

OBJECTIVE

To evaluate retinol levels in patients with or without HAART and to assess the effect of antiretroviral agents on retinal dehydrogenase (RALDH), a key enzyme involved in retinoic acid synthesis.

DESIGN

Plasma retinol levels, measured in six patients receiving HAART and in five others with no antiretroviral therapy, were correlated with levels of serum retinol-binding proteins. We then studied the effects of seven antiretroviral agents on RALDH activity and gene expression in a kidney-derived cell line (LLCPK).

RESULTS

Plasma retinol levels in patients receiving HAART were decreased in comparison with those not receiving antiretroviral drugs (51 +/- 5 versus 66 +/- 11 microg/dl; P = 0.03), whereas retinol-binding protein levels were increased (68 +/- 18 versus 45 +/- 10 mg/l; P = 0.04). RALDH activity was heightened by ritonavir (24%), indinavir (17%), saquinavir (17%), zalcitabine (14%), delavirdine (12%) and nelfinavir (10%) and decreased (22%) by DMP-450. RALDH gene expression was induced only by indinavir.

CONCLUSIONS

These data indicate that certain retinoid-like adverse effects in HAART-receiving patients are not due to higher retinol levels. Enhanced RALDH activity or/and gene expression by some protease inhibitors could increase retinoic acid concentrations. Elevated retinoic acid levels might be responsible for retinoid-like or other adverse effects due to alterations in the expression of retinoic acid-responsive genes.

Recurrent ingrown toenails secondary to indinavir/ritonavir combination therapy

OBJECTIVE

To report five cases of ingrown toenails (IGTN) associated with indinavir/ritonavir (IDV/RTV) combination therapy.

CASE SUMMARY

The median onset of IGTN from initiation of IDV/RTV therapy was 18.4 weeks. Four patients previously received IDV, with one of these experiencing prior IGTN. All patients required surgical management of IGTN. All patients received virologic benefit from ongoing antiretroviral therapy, and the majority of patients elected to maintain IDV/RTV combination therapy. Two patients experienced recurrent IGTN while receiving ongoing IDV/RTV combination therapy.

DISCUSSION

IGTN and paronychia have previously been reported with IDV and lamivudine. IGTN in patients with HIV infection is more likely to present acutely, involve more digits, and require surgical management IDV increases retinoic acid signaling and, based on elevated IDV concentrations from concomitant RTV therapy, the risk of IGTN may be increased in patients receiving IDV/RTV combination therapy.

CONCLUSIONS

With the increasing popularity of IDV/RTV combination therapy, clinicians should be aware of the potential increase in frequency of dose-related toxicities including IGTN. Evaluation of hands and feet on physical examination should be recommended for all patients being treated with lamivudine and IDV, especially when used in combination with RTV.

Systemic sequential therapy of psoriasis: a new paradigm for improved therapeutic results

Sequential therapy is a treatment strategy involving the use of specific therapeutic agents in a deliberate sequence to optimize the therapeutic outcome. The rationale for this strategy in psoriasis is that it is a chronic disease requiring long-term maintenance therapy as well as quick relief of symptoms and that some therapies available for psoriasis are better suited for rapid clearance while others are more appropriate for long-term maintenance. Sequential therapy involves 3 main steps: (1) the clearing, or "quick-fix" phase; (2) the transitional phase; and (3) the maintenance phase. In the example of sequential systemic therapy described in this article, an acute exacerbation of psoriasis is brought under control promptly with the use of cyclosporine at maximum dermatologic dose (5 mg/kg daily). After 1 month, the transitional phase is initiated with the gradual introduction of acitretin as a maintenance agent. Once the maximum tolerated dose of acitretin has been established, cyclosporine is gradually tapered and acitretin is continued for long-term maintenance with phototherapy (UVB or PUVA) added for improved control if needed. The author proposes sequential therapy with cyclosporine and acitretin as a viable option for patients with psoriasis who require systemic therapy and desire an alternative to methotrexate.

Optimizing therapy: tazarotene in combination with phototherapy

Phototherapy is often used in combination with other antipsoriatic treatments in an attempt to improve efficacy and reduce patients' cumulative exposure to radiation. Although this aim has been achieved with some combinations, the additional therapies often introduce a potential risk of other tolerability and safety problems. The efficacy of tazarotene reported in clinical trials to date suggest that this drug may help to improve the efficacy of phototherapy, and perhaps reduce the ultraviolet light exposure required without introducing additional, clinically significant problems. Preliminary results from the first 10 patients in a clinical trial investigating such combination therapy are reported here. They demonstrate that the addition of tazarotene to UVB phototherapy increases the percentage of patients achieving treatment success (> or = 50% global improvement in psoriasis) from 60% to 100% at Day 81. The UVB plus tazarotene combination achieved consistently greater reductions in the elevation and scaling of difficult-to-treat psoriatic plaques than UVB phototherapy alone or UVB phototherapy plus vehicle gel. The tazarotene combination therapy also achieved initial treatment success in less than half the time needed with phototherapy alone (median of 32 vs. 67 days). Combining UVB phototherapy with tazarotene treatment appears to offer a valuable therapeutic option that is more efficacious and faster than UVB phototherapy alone.

Human leukemic K562 cells treated with cytosine arabinoside: enhancement of erythroid differentiation by retinoic acid and retinol

Human leukemia K562 cells can be induced to erythroid differentiation when treated with a variety of compounds, including hemin, cytosine arabinoside and 5-azacytidine. Following erythroid induction, K562 cells express at high level gamma-globin and accumulate both Hb Portland and Hb Gower 1. In this paper we determined whether a combination treatment of K562 cells with suboptimal concentrations of cytosine arabinoside and retinoids lead to full expression of differentiated functions. Cell growth kinetics studies, intracellular detection of hemoglobin by benzidine staining and hemoglobin analysis by cellulose acetate were performed. The results obtained show that (a) retinoic acid and retinol are not able to induce differentiation of K562 cells and (b) cytosine arabinoside induces differentiation only when used at 100-300 nmol/l concentrations. In addition, our data demonstrate that erythroid differentiation of K562 occurs when 40 micromol/l of retinoic acid or retinol are added together with 75 nmol/l cytosine arabinoside.

Occurrence of gouty tophi following acitretin therapy

Acitretin (Ro 10-1670 or Neotigason), a free acid and the main metabolite of etretinate (Ro 10-9359 or Tigason), is the most recent of the retinoids used orally in the treatment of psoriasis and numerous other dermatoses exhibiting disorders of keratinization. In the majority of cases, its side-effects are similar to those of hypervitaminosis A.

Effects of all-trans-retinoic acid on the dorsal skin of hairless dogs

Daily topical treatment with all-trans-retinoic acid (t-RA; 0.1% t-RA solution or 0.05% t-RA cream) was compared with its vehicle with regard to improvement of intrinsically aged skin of hairless descendants of Mexican hairless dogs. After 1 mo of treatment with 0.1% t-RA solution, improvements were noted in skin texture, wrinkling, and pigmentation. Treatment with 0.05% t-RA cream caused an intense adverse effect, retinoid dermatitis. Histologically, 0.1% t-RA solution induced restoration of the skin structure of hairless dogs, resulting in an apparent increase in compaction of the stratum corneum and the epidermal thickness. The epidermis became hyperplastic with definite development of the stratum granulosum. The border between the epidermis and dermis became wavy, and dermal papillae were reconstituted. The 0.1% t-RA solution caused a remarkable decrease in melanin granules. In the dermis, the number of small vessels increased and vasodilation was seen. In sites treated with 0.05% t-RA cream, the stratum corneum became involved in dyskeratotic changes. There was a significantly greater increase in epidermal and granular layer thickness. Necrotic and edematous changes were found in the epidermis, and severe inflammatory reactions were also observed in the dermis. In the t-RA-untreated sites, the structure of the aged skin remained histologically unimproved during the study. The results suggest that hairless dogs are useful laboratory animals for evaluating the effectiveness and side effects of t-RA agents.

The effect of addition of calcipotriol ointment (50 micrograms/g) to acitretin therapy in psoriasis

Our purpose was to find out whether the addition of calcipotriol ointment (50 micrograms/g) to systemic treatment with acitretin produces additional therapeutic effects and thereby an acitretin-sparing effect, and further to investigate the safety and tolerability of this combination. A multicentre, randomized, double-blind placebo-controlled study was designed. Patients were randomized to receive calcipotriol or placebo. All patients were treated with a starting dose of 20 mg acitretin per day and doses were adjusted at 2-weekly intervals with increments of 10 mg per day up to a maximum of 70 mg per day. The dose requirement for acitretin, clinical signs and adverse events were recorded. Seventy-six patients were randomized to treatment with calcipotriol 50 micrograms/g ointment twice daily and 59 patients to treatment with the vehicle only twice daily. Clearance or marked improvement was achieved by 67% of the patients in the calcipotriol group and by 41% of the patients in the placebo group (P = 0.006). Calcipotriol treatment proved to have a statistically significant additional effect to acitretin on the Psoriasis Area and Severity Index, redness, thickness and scaliness as compared with placebo. Clearance or marked improvement was achieved with a statistically significantly lower cumulative dose of acitretin by the patients in the calcipotriol group as compared with the placebo group. The number of patients reporting adverse events was pronounced and largely related to acitretin. No significant differences were observed between the two treatment groups with respect to adverse events. Laboratory assessments were essentially normal. The addition of calcipotriol ointment to acitretin treatment contributes to the efficacy, reduces the cumulative dose of acitretin to reach marked improvement or clearance, and is well-tolerated and safe.

Oral retinoids and pregnancy

The oral retinoids isotretinoin and etretinate are uniquely effective in the treatment of severe cystic acne and keratinisation disorders. Because of their known teratogenicity, there are strict prescription guidelines, but exposure during pregnancy still occurs. A dedicated effort by women and their clinicians is required, involving patient selection, education and informed consent, detailed contraceptive counselling, and careful monitoring and management, including pregnancy testing before commencement of therapy.

Isotretinoin for acne vulgaris

BACKGROUND

The clinical efficacy of oral isotretinoin in the treatment of severe acne is now well established and so are the clinical and laboratory adverse effects of the drug. Isotretinoin was first introduced in Saudi Arabia late in 1987. In this 7-year retrospective study, efficacy and side effects of isotretiunoin are reviewed in Saudi patients with acne vulgaris seen in a university skin clinic in Riyadh, Saudi Arabia.

MATERIALS AND METHODS

A total of 262 patients had been treated with isotretinoin. Their case records were studied with reference to demographic data, clinical findings, dosage of isotretinoin, response to the drug, and the prevalence and severity of clinical and laboratory adverse effects.

RESULTS

Only 156 case records (69.9% women) could be evaluated. Most patients received 0.60 to 0.75 mg of isotretinoin per kg per day for a period ranging from 16 to 35 weeks (mean +/- SD: 21.2 +/- 3.3 weeks); a total cumulative dose of 75 to 146 mg per kg (mean +/- SD: 104 +/- 10.6 mg per kg). Approximately 56% of the patients had therapy-resistant moderate acne and only 14% had nodulocystic acne. Of the patients, 90.4% had an excellent response and 3.8% were poor responders. Adverse effects occurred in 99% of the patients, but in no case did they lead to discontinuation of the drug. Except for minor differences in prevalence, the clinical side effects were similar to those reported in the literature. Elevation of plasma triglyceride levels was the most significant laboratory adverse effect.

CONCLUSIONS

This is the first report on the experience with isotretinoin in the treatment of acne in the Middle East. Moderate doses of isotretinoin are well tolerated and produce excellent results in Saudi patients with acne.

Retinoic acid receptor gamma mediates topical retinoid efficacy and irritation in animal models

Among retinoic acid receptors (RARs) alpha, beta, and gamma, the messenger RNA level of RAR-gamma is the most readily detectable by Northern blotting in human and mouse skin. This observation suggests that RAR-gamma may play a critical role in the modulation of the therapeutic benefits and side effects of retinoids in skin. To test this hypothesis, 11 RAR-gamma selective retinoids were synthesized based on three related structures. Each compound was found to prefer RAR-gamma when assessed by retinoid-induced transcriptional activity (RAR-gamma > RAR-beta > RAR-alpha). The apparent Kd for binding to recombinant receptor protein was found to follow a similar trend. To correlate this receptor selectivity with in vivo activity, the compounds were tested topically in the Rhino mouse utriculi reduction and rabbit irritation models, two assays widely used to screen retinoids for efficacy and side effects, respectively. The results indicated that for these compounds, both efficacy in the utriculi reduction assay and irritation potential in rabbits correlated positively with the RAR-gamma transactivation activity, with r2 of 0.9 and 0.8, respectively. These data suggest that RAR-gamma is an important regulator of retinoic acid efficacy in skin and further, that the irritation associated with the use of retinoids is most likely a receptor-mediated process.

Extensive extraspinal hyperostoses after long-term oral retinoid treatment in a patient with pityriasis rubra pilaris

We describe a patient with severe pityriasis rubra pilaris in whom extensive extraspinal hyperostoses developed after 13 years of oral retinoid treatment. The most prominent abnormality was a bridging exostosis between the left acetabulum and collum. X-ray examinations of the spine during retinoid therapy showed no abnormalities. During oral retinoid treatment, it is important to ask the patient on a regular basis about any skeletal pains or mobility restriction. Normal spinal x-ray results are no guarantee that a patient is free of hyperostoses. Discontinuation of acitretin therapy resulted in a severe exacerbation of the patient's pityriasis rubra pilaris after 2 weeks. The clinical response to administration of azathioprine was clearly inferior to that of acitretin. However, low-dose oral methotrexate therapy appeared to be a good alternative in this patient, with a clinical result comparable to acitretin and no side effects after 6 months of therapy.

Retinoids and the skin

Retinoids are a group of naturally occurring and synthetic compounds with vitamin A-like biological activity. They play an important role in vision, reproduction, growth, and epithelial cell differentiation. Recent discoveries of specific retinoid cellular binding proteins and nuclear receptors have led to a better (although not complete) understanding of the complex mechanisms of retinoid action. Numerous clinical studies have demonstrated beneficial effects of retinoids on skin diseases such as acne, psoriasis, ichthyoses, keratodermas, skin cancers and their precursors, as well as a reversal of the effects of photoaging.