Side effects of retinoid therapy on the quality of vision

Computational refinement identifies functional destructive single nucleotide polymorphisms associated with human retinoid X receptor gene

Alterations in the nuclear retinoid X receptor (RXRs) signalling have been implicated in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis and glaucoma. Single nucleotide polymorphisms (SNPs) are the main cause underlying single nucleic acid variations which in turn determine heterogeneity within various populations. These genetic polymorphisms have been suggested to associate with various degenerative disorders in population-wide analysis. This bioinformatics study was designed to investigate, search, retrieve and identify deleterious SNPs which may affect the structure and function of various RXR isoforms through a computational and molecular modelling approach. Amongst the 1,813 retrieved SNPs several were found to be deleterious with rs140464195_G139R, rs368400425_R358W and rs368586400_L383F RXRα mutant variants being the most detrimental ones causing changes in the interatomic interactions and decreasing the flexibility of the mutant proteins. Molecular genetics analysis identified seven missense mutations in RXRα/β/γ isoforms. Two novel mutations SNP IDs (rs1588299621 and rs1057519958) were identified in RXRα isoform. We used several in silico prediction tools such as SIFT, PolyPhen, I-Mutant, Protein Variation Effect Analyzer (PROVEAN), PANTHER, SNP&Go, PhD-SNP and SNPeffect to predict pathogenicity and protein stability associated with RXR mutations. The structural assessment by DynaMut tool revealed that hydrogen bonds were affected along with hydrophobic and carbonyl interactions resulting in reduced flexibility at the mutated residue positions but ultimately stabilizing the molecule as a whole. Summarizing, analysis of the missense mutations in RXR isoforms showed a mix of conclusive and inconclusive genotype-phenotype correlations suggesting the use of sophisticated computational analysis tools for studying RXR variants.Communicated by Ramaswamy H. Sarma.

Retinoid-associated myopia in dermatologic patients: a systematic review

Systemic retinoids are among the most prescribed drugs in dermatology, thanks to their activity as proliferation modulators and keratinization normalizers. Common side effects such as blood lipid disorders, xerosis and photosensitivity are well established and usually dose dependent. Conversely, retinoid-associated ocular disturbances have been reported, yet with differences in terms of frequency and manifestations. As data regarding a potential correlation with refractive errors are heterogenous and have not been previously thoroughly addressed, we performed a systematic review of the literature with the aim of comprehensively evaluating the current evidence regarding retinoid-associated myopia in dermatologic patients.

Topical adapalene for the treatment of follicular conjunctivitis due to periocular molluscum contagiosum in children

Purpose

Periocular molluscum contagiosum can cause a chronic secondary follicular conjunctivitis or keratoconjunctivitis that rarely leads to corneal scarring and visual impairment. We describe two cases of follicular conjunctivitis due to periocular molluscum contagiosum that were successfully treated with topical adapalene 0.1%.

Observations

Case 1 is a 9-year old female with a history of leg molluscum contagiosum who presented with three 1mm flesh-colored umbilicated papules on the periocular skin of the right eye with associated follicular conjunctivitis and diffuse corneal punctate epithelial erosions. Ocular symptoms were persistent for 6 months. Case 2 is a 4-year old female with a 3-month history of right periocular bumps and one month of conjunctival redness with eyelid edema. Examination revealed umbilicated flesh colored nodules on the right upper and lower eyelids with associated trace conjunctival injection. Both patients experienced rapid resolution of both eyelid involvement and conjunctivitis following the use of twice daily topical adapalene 0.1% to the eyelid lesions, with no reported side effects.

Conclusions and importance

Topical adapalene 0.1% is a cost-effective, convenient, and non-toxic over-the-counter retinoid cream that should be considered for first-line therapy in the treatment of periocular molluscum contagiosum and any associated conjunctivitis.

The Role of Vitamin A in Retinal Diseases

Vitamin A is an essential fat-soluble vitamin that occurs in various chemical forms. It is essential for several physiological processes. Either hyper- or hypovitaminosis can be harmful. One of the most important vitamin A functions is its involvement in visual phototransduction, where it serves as the crucial part of photopigment, the first molecule in the process of transforming photons of light into electrical signals. In this process, large quantities of vitamin A in the form of 11-cis-retinal are being isomerized to all-trans-retinal and then quickly recycled back to 11-cis-retinal. Complex machinery of transporters and enzymes is involved in this process (i.e., the visual cycle). Any fault in the machinery may not only reduce the efficiency of visual detection but also cause the accumulation of toxic chemicals in the retina. This review provides a comprehensive overview of diseases that are directly or indirectly connected with vitamin A pathways in the retina. It includes the pathophysiological background and clinical presentation of each disease and summarizes the already existing therapeutic and prospective interventions.

Ophthalmic Assessment in Patients With Darier Disease

PURPOSE

To assess the prevalence of ophthalmic findings in patients with Darier disease, an autosomal dominant genetic skin disorder, in an effort to evaluate the need for eye examinations in the management of the disease.

DESIGN

Prospective observational case series.

METHODS

Thirty-six individuals with Darier disease were evaluated by both ocular assessment questionnaire and a comprehensive ophthalmic examination (visual acuity, refraction, external examination, and slit-lamp examination) with emphasis on the eyelids, conjunctiva, and cornea. In addition, questionnaire-based medical interview and skin examination were conducted.

RESULTS

According to the medical questionnaire, 39% of patients reported eye problems, 36% dry eye, and 42% eye fatigue after prolonged reading. Ocular examination revealed Darier disease lesions on the eyelids in 55% of the patients, blepharitis in 44%, conjunctival hyperemia in 28%, and short tear film break-up time in 83%. There was no significant relationship between any of these ophthalmic findings and systemic retinoid therapy, sex, or age.

CONCLUSIONS

The high prevalence of blepharitis and dry eye highlights the importance of ophthalmologic evaluation of patients with Darier disease.

Consensus recommendations for the use of retinoids in ichthyosis and other disorders of cornification in children and adolescents

Topical and systemic retinoids have long been used in the treatment of ichthyoses and other disorders of cornification. Due to the need for long-term use of retinoids for these disorders, often beginning in childhood, numerous clinical concerns must be considered. Systemic retinoids have known side effects involving bone and eye. Additionally, potential psychiatric and cardiovascular effects need to be considered. Contraceptive concerns, as well as the additive cardiovascular and bone effects of systemic retinoid use with hormonal contraception must also be deliberated for patients of childbearing potential. The Pediatric Dermatology Research Alliance (PeDRA) Use of Retinoids in Ichthyosis Work Group was formed to address these issues and to establish best practices regarding the use of retinoids in ichthyoses based on available evidence and expert opinion.

Flavonoids enhance rod opsin stability, folding, and self-association by directly binding to ligand-free opsin and modulating its conformation

Rhodopsin (Rho) is a visual G protein-coupled receptor expressed in the rod photoreceptors of the eye, where it mediates transmission of a light signal into a cell and converts this signal into a nerve impulse. More than 100 mutations in Rho are linked to various ocular impairments, including retinitis pigmentosa (RP). Accordingly, much effort has been directed toward developing ligands that target Rho and improve its folding and stability. Natural compounds may provide another viable approach to such drug discovery efforts. The dietary polyphenol compounds, ubiquitously present in fruits and vegetables, have beneficial effects in several eye diseases. However, the underlying mechanism of their activity is not fully understood. In this study, we used a combination of computational methods, biochemical and biophysical approaches, including bioluminescence resonance energy transfer, and mammalian cell expression systems to clarify the effects of four common bioactive flavonoids (quercetin, myricetin, and their mono-glycosylated forms quercetin-3-rhamnoside and myricetrin) on rod opsin stability, function, and membrane organization. We observed that by directly interacting with ligand-free opsin, flavonoids modulate its conformation, thereby causing faster entry of the retinal chromophore into its binding pocket. Moreover, flavonoids significantly increased opsin stability, most likely by introducing structural rigidity and promoting receptor self-association within the biological membranes. Of note, the binding of flavonoids to an RP-linked P23H opsin variant partially restored its normal cellular trafficking. Together, our results suggest that flavonoids could be utilized as lead compounds in the development of effective nonretinoid therapeutics for managing RP-related retinopathies.

Liposome: composition, characterisation, preparation, and recent innovation in clinical applications

In the last decades, pharmaceutical interested researches aimed to develop novel and innovative drug delivery techniques in the medical and pharmaceutical fields. Recently, phospholipid vesicles (Liposomes) are the most known versatile assemblies in the drug delivery systems. The discovery of liposomes arises from self-forming enclosed phospholipid bilayer upon coming in contact with the aqueous solution. Liposomes are uni or multilamellar vesicles consisting of phospholipids produced naturally or synthetically, which are readily non-toxic, biodegradable, and are readily produced on a large scale. Various phospholipids, for instance, soybean, egg yolk, synthetic, and hydrogenated phosphatidylcholine consider the most popular types used in different kinds of formulations. This review summarises liposomes composition, characterisation, methods of preparation, and their applications in different medical fields including cancer therapy, vaccine, ocular delivery, wound healing, and some dermatological applications.

Chemoprevention of Head and Neck Cancers: Does It Have Only One Face?

Head and neck squamous cell cancer (HNSCC) represents a significant burden worldwide. Chemoprevention of HNSCC is a means of cancer control with a use of drugs or natural agents in order to hinder or delay the cancer development. The purpose of this article is to review mechanism of action of different chemopreventive agents' groups and results of most important researches concerning them. The safety issues of HNSCC chemoprevention are also discussed. In case of HNSCC there is currently no agent, which would give positive result in the third phase of clinical trials. Promising results of preclinical trials are not always confirmed by further tests. Main problems are low effectiveness, high toxicity, and lack of highly specificity biomarkers for monitoring the research. New trials concerning many agents, as well as novel technologies for provision of pharmaceutical forms of them, including drug nanocarriers, are currently underway, which gives hope for finding the perfect chemopreventive agent formula.

Efficacy and Safety of the Traditional Japanese Medicine Keigairengyoto in the Treatment of Acne Vulgaris

Several traditional Japanese medicines including Keigairengyoto (KRT) are used to treat acne vulgaris, but there is no robust evidence of their effectiveness. In this study, we examined the effectiveness and safety of KRT in treating acne vulgaris. An open-label, randomized, parallel control group comparison was conducted with a conventional treatment group (adapalene and topical antibiotics; control group) and a KRT group (control treatment plus KRT). The test drugs were administered for 12 weeks to patients (15 to 64 years, outpatient) with inflammatory acne on their face, and the amount of acne at 2, 4, 8, and 12 weeks was measured. Sixty-four patients were enrolled; 29 patients in each group were included in the analysis. Twenty-eight patients in the control group and 24 patients in the KRT group were included in the efficacy analysis. The number of inflammatory skin rashes at 4 and 8 weeks in the KRT group was significantly decreased compared with the control group. There was no significant difference between the two groups in noninflammatory eruptions and general rashes. There were no serious adverse events in both groups. KRT may be a useful agent in patients with inflammatory acne in combination with conventional treatments. This trial is registered with UMIN 000014831.