Successful Treatment of Primary Cutaneous Peripheral T-Cell Lymphoma Presenting Acquired Ichthyosis with Oral Bexarotene Monotherapy

Acquired ichthyosis: a clinical review

Acquired ichthyosis (AI) is a rare, nonhereditary cutaneous disorder that has been associated with numerous neoplastic, infectious, drugs, endocrine, metabolic, autoimmune, and malabsorptive diseases. Review all demographical, clinical, histological, and therapeutic features of AI and focus on all reported associated diseases. We performed a systematic literature review in Pubmed/Medline, Embase, and Cochrane collaboration databases, searching for all articles on AI, with no limits on publication date, participant age, sex or nationality. Eighty-four articles were included. Total number of included patients was 167 patients with a mean age at presentation of 39 years [range 0.5-85] and a sex ratio M:F of 5:2. The most common malignancy associated with AI is Hodgkin's lymphoma. AI occurred before, simultaneously or after the onset of malignancy or systemic disease. The severity of AI depends on the severity of the underlying disorder and regresses once the disease goes into remission and may also be a marker of disease recurrence or relapse. 8% have been reported to be drug related and all occurred weeks to months after drug intake and resolved after stopping or decreasing the dose of the drug. Data were derived from case reports and observational studies. Limitations include the accuracy of published data, potential patient selection, and reporting bias. AI can be associated with numerous systemic diseases and drugs. Physicians should be particularly alert to these associations to provide adequate screening and management of patients with AI.

Regulation of HDAC11 gene expression in early myogenic differentiation

Histone acetylation and deacetylation affect the patterns of gene expression in cellular differentiation, playing pivotal roles in tissue development and maintenance. For example, the intrinsic histone acetyltransferase activity of transcriptional coactivator p300 is especially required for the expression of myogenic regulatory factors including Myf5 and MyoD, and consequently for skeletal myogenesis. On the other hand, histone deacetylases (HDACs) remove the acetyl group from histones, which is critical for gene repression in stem cell fate transition. Through integrative omic analyses, we found that while some HDACs were differentially expressed at the early stage of skeletal myoblast differentiation, Hdac11 gene expression was significantly enhanced by nuclear receptor signaling. In addition, p300 and MyoD control Hdac11 expression in milieu of normal and signal-enhanced myoblast differentiation. Thus, HDAC11 may be essential to differential gene expression at the onset of myoblast differentiation.

Acquired ichthyosis, asteatotic dermatitis or xerosis? An update on pathoetiology and drug-induced associations

Acquired ichthyosis (AI) is a relatively rare cutaneous entity characterized by transient, generalized scaling and pruritus in the absence of family history of ichthyosis or atopic disease. The hyperkeratosis in AI can range from the mild, white-to-brown scaling resembling that in ichthyosis vulgaris (IV) to the more prominent dark brown scaling phenotype, similar to that found in lamellar ichthyosis. The disease can wax and wane in relation to endogenous and/or exogenous factors. Histopathology of AI is similar to that found in IV. AI is usually of cosmetic concern to patients but can, in some cases, reflect the presence of more serious conditions, including malignancies, autoimmune diseases or metabolic disorders. In some cases, AI can be an adverse effect of a medication or the cutaneous symptom of a toxic exposure. Other conditions, such as severe xerosis or eczema, can present with clinical findings similar to AI, making diagnosis a challenge. Furthermore, cases of AI are sporadic throughout the literature and have been documented across a wide variety of medical settings distinct from dermatology, which often contribute to misdiagnosis of this disease. Definitive management requires prompt identification and treatment of the inciting factors combined with conservative therapies, which can include topical emollients, keratolytics, retinoids or corticosteroids, and in rare cases, oral retinoids.

Ichthyosis (concept, pathohistology, clinical picture, treatment)

Ichthyosis is a skin disease that is hereditary, has pronounced symptoms in the form of a violation of the skin, and the presence of formations resembling fish scales. It is possible to distinguish different approaches to the definition of ichthyosis, based on the modern study of this issue. Ichthyosis is classified by type: congenital and acquired. Congenital ichthyosis has its own classification depending on the manifestation of changes in the skin, the course of the disease, concomitant pathologies. Congenital ichthyosis is divided into ordinary (vulgar autosomal dominant, simple) ichthyosis, lamellar ichthyosis (dry ichthyosiform erythroderma, "collodion child", lamellar ichthyosis), X-linked ichthyosis (ichthyosis associated with the X chromosome, blackening ichthyosis), congenital bullous ichthyosiform erythroderma (erythroderma Broca's disease, ichthyosiform epidermolytic hyperkeratosis), fetal ichthyosis (intrauterine ichthyosis, universal hyperkeratosis, "Harlequin fetus", congenital keratosis), other congenital ichthyosis. Ichthyosiform conditions (the so-called acquired ichthyosis) are divided into symptomatic, age-related (senile), discoid ichthyosis. The causes of acquired ichthyosis can be various diseases, taking medications, improper skin care, unbalanced nutrition. Each form of ichthyosis differs by the type of inheritance, prevalence in the population, clinical picture, verified by histological examination of skin biopsies and electron microscopic examination of the skin. It may be accompanied by seasonality of exacerbation of the clinical picture, association with other diseases (allergic, diseases of the gastrointestinal tract, congenital malformations). There is no specific treatment for ichthyosis. In systemic therapy, derivatives of vitamin A are used, keratolytics, as well as moisturizing and emollient agents are used for external treatment. The use of therapeutic baths, general ultraviolet irradiation is effective.

Astaxanthin exerts protective effects similar to bexarotene in Alzheimer's disease by modulating amyloid-beta and cholesterol homeostasis in blood-brain barrier endothelial cells

The pathogenesis of Alzheimer's disease (AD) is characterized by overproduction, impaired clearance, and deposition of amyloid-β peptides (Aβ) and connected to cholesterol homeostasis. Since the blood-brain barrier (BBB) is involved in these processes, we investigated effects of the retinoid X receptor agonist, bexarotene (Bex), and the peroxisome proliferator-activated receptor α agonist and antioxidant, astaxanthin (Asx), on pathways of cellular cholesterol metabolism, amyloid precursor protein processing/Aβ production and transfer at the BBB in vitro using primary porcine brain capillary endothelial cells (pBCEC), and in 3xTg AD mice. Asx/Bex downregulated transcription/activity of amyloidogenic BACE1 and reduced Aβ oligomers and ~80 kDa intracellular 6E10-reactive APP/Aβ species, while upregulating non-amyloidogenic ADAM10 and soluble (s)APPα production in pBCEC. Asx/Bex enhanced Aβ clearance to the apical/plasma compartment of the in vitro BBB model. Asx/Bex increased expression levels of ABCA1, LRP1, and/or APOA-I. Asx/Bex promoted cholesterol efflux, partly via PPARα/RXR activation, while cholesterol biosynthesis/esterification was suppressed. Silencing of LRP-1 or inhibition of ABCA1 by probucol reversed Asx/Bex-mediated effects on levels of APP/Aβ species in pBCEC. Murine (m)BCEC isolated from 3xTg AD mice treated with Bex revealed elevated expression of APOE and ABCA1. Asx/Bex reduced BACE1 and increased LRP-1 expression in mBCEC from 3xTg AD mice when compared to vehicle-treated or non-Tg treated mice. In parallel, Asx/Bex reduced levels of Aβ oligomers in mBCEC and Aβ species in brain soluble and insoluble fractions of 3xTg AD mice. Our results suggest that both agonists exert beneficial effects at the BBB by balancing cholesterol homeostasis and enhancing clearance of Aβ from cerebrovascular endothelial cells.

Successful Treatment of Advanced Primary Cutaneous Peripheral T-Cell Lymphoma with Oral Bexarotene Monotherapy

Bexarotene is a third-generation retinoid X receptor-selective retinoid that is widely used for the early treatment of advanced-stage cutaneous T-cell lymphomas. In this report, we describe a case of successful treatment of advanced primary cutaneous peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) with oral bexarotene monotherapy. After the administration of oral bexarotene at a dose of 300 mg/m²/day, all skin lesions and lymph nodes regressed, and complete remission was achieved for 1 year. Our case suggested that bexarotene monotherapy could be one of the possible therapies for the treatment of primary cutaneous PTCL-NOS.