Guidelines of care for the management of acne vulgaris

BACKGROUND

Acne vulgaris commonly affects adults, adolescents, and preadolescents aged 9 years or older.

OBJECTIVE

The objective of this study was to provide evidence-based recommendations for the management of acne.

METHODS

A work group conducted a systematic review and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach for assessing the certainty of evidence and formulating and grading recommendations.

RESULTS

This guideline presents 18 evidence-based recommendations and 5 good practice statements. Strong recommendations are made for benzoyl peroxide, topical retinoids, topical antibiotics, and oral doxycycline. Oral isotretinoin is strongly recommended for acne that is severe, causing psychosocial burden or scarring, or failing standard oral or topical therapy. Conditional recommendations are made for topical clascoterone, salicylic acid, and azelaic acid, as well as for oral minocycline, sarecycline, combined oral contraceptive pills, and spironolactone. Combining topical therapies with multiple mechanisms of action, limiting systemic antibiotic use, combining systemic antibiotics with topical therapies, and adding intralesional corticosteroid injections for larger acne lesions are recommended as good practice statements.

LIMITATIONS

Analysis is based on the best available evidence at the time of the systematic review.

CONCLUSIONS

These guidelines provide evidence-based recommendations for the management of acne vulgaris.

Efficacy and Tolerability of Topical 0.1% Stabilized Bioactive Retinol for Photoaging: A Vehicle-Controlled Integrated Analysis

INTRODUCTION

Chronic exposure to ultraviolet light photoages skin. Retinol, a precursor molecule to retinoic acid that causes less irritation, is available as a nonprescription, cosmetic retinoid and improves collagen production, skin elasticity, and signs of photoaging. Advances in formulation science have allowed the production of stabilized bioactive retinol formulations. This integrated analysis aims to build on previous studies and further examine the comprehensive efficacy and tolerability of topical 0.1% stabilized bioactive retinol.

METHODS

This analysis included 6 vehicle-controlled studies of 0.1% stabilized bioactive retinol in women with mild-to-moderate signs of photodamage. Across all studies, the same dermatologist investigator assessed overall photodamage; wrinkles on the forehead, cheeks, and undereye area; crow’s feet wrinkles and fine lines; lack of even skin tone; and brown spots at baseline and weeks 4, 8, and 12 on a numerical scale. Tolerability was also assessed.

RESULTS

Participants (retinol, N=237; vehicle, N=234) had a mean (SD) age of 47.4 (6.6) years. Retinol induced greater improvements from baseline in all signs of photoaging vs vehicle as early as week 4 and through 12 weeks of application. Few participants experienced irritation; all events were mild to moderate and transient. The most common signs of irritation were erythema (n=2) and skin scaling/peeling (n=5).

CONCLUSIONS

This pooled analysis of 6 vehicle-controlled clinical studies provides new evidence for the efficacy of 0.1% stabilized bioactive retinol in improving signs of photoaging without causing major irritation. Topical 0.1% stabilized bioactive retinol was well tolerated with only a few reported cases of skin irritation. J Drugs Dermatol. 2024;23(4):     doi:10.36849/JDD.8124.

Retinoid orphan receptor gamma t (rorγt) promotes inflammatory eosinophilia but is dispensable for innate immune-mediated colitis

Inflammatory bowel diseases (IBD) result from uncontrolled inflammation in the intestinal mucosa leading to damage and loss of function. Both innate and adaptive immunity contribute to the inflammation of IBD and innate and adaptive immune cells reciprocally activate each other in a forward feedback loop. In order to better understand innate immune contributions to IBD, we developed a model of spontaneous 100% penetrant, early onset colitis that occurs in the absence of adaptive immunity by crossing villin-TNFAIP3 mice to RAG1-/- mice (TRAG mice). This model is driven by microbes and features increased levels of innate lymphoid cells in the intestinal mucosa. To investigate the role of type 3 innate lymphoid cells (ILC3) in the innate colitis of TRAG mice, we crossed them to retinoid orphan receptor gamma t deficient (Rorγt-/-) mice. Rorγt-/- x TRAG mice exhibited markedly reduced eosinophilia in the colonic mucosa, but colitis persisted in these mice. Colitis in Rorγt-/- x TRAG mice was characterized by increased infiltration of the intestinal mucosa by neutrophils, inflammatory monocytes, macrophages and other innate cells. RNA and cellular profiles of Rorγt-/- x TRAG mice were consistent with a lack of ILC3 and ILC3 derived cytokines, reduced antimicrobial factors, increased activation oof epithelial repair processes and reduced activation of epithelial cell STAT3. The colitis in Rorγt-/- x TRAG mice was ameliorated by antibiotic treatment indicating that microbes contribute to the ILC3-independent colitis of these mice. Together, these gene expression and cell signaling signatures reflect the double-edged sword of ILC3 in the intestine, inducing both proinflammatory and antimicrobial protective responses. Thus, Rorγt promotes eosinophilia but Rorγt and Rorγt-dependent ILC3 are dispensable for the innate colitis in TRAG mice.

Microsomal triglyceride transfer protein is necessary to maintain lipid homeostasis and retinal function

Lipid processing by the retinal pigment epithelium (RPE) is necessary to maintain retinal health and function. Dysregulation of retinal lipid homeostasis due to normal aging or age-related disease triggers lipid accumulation within the RPE, on Bruch's membrane (BrM), and in the subretinal space. In its role as a hub for lipid trafficking into and out of the neural retina, the RPE packages a significant amount of lipid into lipid droplets for storage and into apolipoprotein B (APOB)-containing lipoproteins (Blps) for export. Microsomal triglyceride transfer protein (MTP), encoded by the MTTP gene, is essential for Blp assembly. Herein we test the hypothesis that MTP expression in the RPE is essential to maintain lipid balance and retinal function using the newly generated RPEΔMttp mouse model. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic depletion of Mttp from the RPE results in intracellular lipid accumulation, increased photoreceptor-associated cholesterol deposits, and photoreceptor cell death, and loss of rod but not cone function. RPE-specific reduction in Mttp had no significant effect on plasma lipids and lipoproteins. While APOB was decreased in the RPE, most ocular retinoids remained unchanged, with the exception of the storage form of retinoid, retinyl ester. Thus suggesting that RPE MTP is critical for Blp synthesis and assembly but is not directly involved in plasma lipoprotein metabolism. These studies demonstrate that RPE-specific MTP expression is necessary to establish and maintain retinal lipid homeostasis and visual function.

Is it time for a retinoic acid-eluting stent or retinoic acid-coated balloon? Insights from experimental studies of systemic and local delivery of retinoids

Although the incidence of restenosis and stent thrombosis has substantially declined during the last decades, they still constitute the two major causes of stent failure. These complications are partially attributed to the currently used cytostatic drugs, which can cause local inflammation, delay or prevent re-endothelialization and essentially cause arterial cell toxicity. Retinoic acid (RA), a vitamin A (retinol) derivative, is a naturally occurring substance used for the treatment of cell proliferation disorders. The agent has pleiotropic effects on vascular smooth muscle cells and macrophages: it influences the proliferation, migration, and transition of smooth muscle cells to other cell types and modulates macrophage activation. These observations are supported by accumulated evidence from in vitro and in vivo experiments. In addition, systemic and topical administration of RA can decrease the development of atherosclerotic plaques and reduce or inhibit restenosis after vascular injury (caused by embolectomy, balloon catheters, or ligation of arteries) in various experimental models. Recently, an RA-drug eluting stent (DES) has been tested in an animal model. In this review, we explore the effects of RA in atherosclerosis and the potential of the local delivery of RA through an RA-DES or RA-coated balloon for targeted therapeutic percutaneous vascular interventions. Despite promising published results, further experimental study is warranted to examine the safety and efficacy of RA-eluting devices in vascular artery disease.

Retinylidene chromophore hydrolysis from mammalian visual and non-visual opsins

Rhodopsin (Rho) and cone opsins are essential for detection of light. They respond via photoisomerization, converting their Schiff-base-adducted 11-cis-retinylidene chromophores to the all-trans configuration, eliciting conformational changes to activate opsin signaling. Subsequent Schiff-base hydrolysis releases all-trans-retinal, initiating two important cycles that maintain continuous vision-the Rho photocycle and visual cycle pathway. Schiff-base hydrolysis has been thoroughly studied with photoactivated Rho but not with cone opsins. Using established methodology, we directly measured the formation of Schiff-base between retinal chromophores with mammalian visual and nonvisual opsins of the eye. Next, we determined the rate of light-induced chromophore hydrolysis. We found that retinal hydrolysis from photoactivated cone opsins was markedly faster than from photoactivated Rho. Bovine retinal G protein-coupled receptor (bRGR) displayed rapid hydrolysis of its 11-cis-retinylidene photoproduct to quickly supply 11-cis-retinal and re-bind all-trans-retinal. Hydrolysis within bRGR in native retinal pigment epithelium microsomal membranes was >6-times faster than that of bRGR purified in detergent micelles. N-terminal-targeted antibodies significantly slowed bRGR hydrolysis, while C-terminal antibodies had no effect. Our study highlights the much faster photocycle of cone opsins relative to Rho and the crucial role of RGR in chromophore recycling in daylight. By contrast, in our experimental conditions, bovine peropsin did not form pigment in the presence of all-trans-retinal nor with any mono-cis retinal isomers, leaving uncertain the role of this opsin as a light sensor.

Effect of a retinoic acid analogue on BMP-driven pluripotent stem cell chondrogenesis

Osteoarthritis is the most common degenerative joint condition, leading to articular cartilage (AC) degradation, chronic pain and immobility. The lack of appropriate therapies that provide tissue restoration combined with the limited lifespan of joint-replacement implants indicate the need for alternative AC regeneration strategies. Differentiation of human pluripotent stem cells (hPSCs) into AC progenitors may provide a long-term regenerative solution but is still limited due to the continued reliance upon growth factors to recapitulate developmental signalling processes. Recently, TTNPB, a small molecule activator of retinoic acid receptors (RARs), has been shown to be sufficient to guide mesodermal specification and early chondrogenesis of hPSCs. Here, we modified our previous differentiation protocol, by supplementing cells with TTNPB and administering BMP2 at specific times to enhance early development (referred to as the RAPID-E protocol). Transcriptomic analyses indicated that activation of RAR signalling significantly upregulated genes related to limb and embryonic skeletal development in the early stages of the protocol and upregulated genes related to AC development in later stages. Chondroprogenitors obtained from RAPID-E could generate cartilaginous pellets that expressed AC-related matrix proteins such as Lubricin, Aggrecan, and Collagen II, but additionally expressed Collagen X, indicative of hypertrophy. This protocol could lay the foundations for cell therapy strategies for osteoarthritis and improve the understanding of AC development in humans.

A pilot study examining a double-conjugated, retinoid-based skincare regimen for darker, blemish-prone skin

BACKGROUND

Retinoids and alpha- and beta hydroxy acids are common components utilized in regimens for blemish-prone skin. However, balancing efficacy and tolerability is often challenging.

PATIENTS/METHODS

This pilot study evaluated a double-conjugated retinoid serum specifically formulated for blemish-prone skin (AHARet-SA) in combination with exfoliating peel pads (double-conjugated retinoid, glycolic, lactic, and salicylic acids), a cleanser, mineral-based sunscreen, and a lightweight moisturizer in female participants with mild-to-moderate blemish-prone skin. Fifty-five percent of participants were Fitzpatrick Skin Type (FST) IV and 27% were FST V. Participants used the exfoliating peel pads (3x/week for 8 weeks; 2x/week for 4 weeks) followed by nightly AHARet-SA and a moisturizer (as needed). Improvements in skin were assessed using the 5-point Investigator Global Assessment Scale, and participant satisfaction and tolerability were assessed over 12 weeks.

RESULTS

Significant mean improvement from baseline in skin clarity occurred after 4 weeks (14%; p = 0.04) with progressive improvements through week 12 (52%; p = 0.004). Eighty-eight percent of participants reported improvements in the appearance and texture of their skin and fewer blemishes/breakouts. Mild, transient adverse events were reported.

CONCLUSIONS

A regimen comprised of a double-conjugated serum and exfoliating peel pads formulated for blemish-prone skin led to significant improvements from baseline in skin clarity after 12 weeks in participants with predominately darker skin tones and mild-to-moderate blemish-prone skin.

Trends in harmful drug exposure during pregnancy in France between 2013 and 2019: A nationwide cohort study

OBJECTIVE

Describe the trends of exposure to harmful drugs during pregnancy over recent years in France.

DESIGN

Nationwide cohort study.

SETTING

The French National administrative health Data System (SNDS).

POPULATION

Pregnancies starting between 2013 and 2019 and outcomes corresponding to live births, medical terminations of pregnancy, and stillbirths.

METHODS

Each pregnancy was divided into a preconceptional period of 90 days before conception and three trimesters from conception to birth. Harmful drugs were defined according to their risks to the fetus: teratogenicity or fetotoxicity. Exposure was defined using the critical period during pregnancy for each type of harmful drug: preconceptional period or first trimester for teratogenic drugs and second or third trimesters for fetotoxic drugs.

MAIN OUTCOME MEASURES

Prevalence of pregnancies exposed to at least one harmful drug.

RESULTS

Among 5,253,284 pregnancies, 204,402 (389 per 10,000) pregnancies were exposed to at least one harmful drug during the critical periods: 48,326 (92 per 10,000) pregnancies were exposed to teratogenic drugs during the preconceptional period or the first trimester, and 155,514 (299 per 10,000) pregnancies were exposed to fetotoxic drugs during the second or third trimesters. Teratogenic drugs were mainly retinoids for topical use (44 per 10,000 pregnancies), antiepileptics (13 per 10,000 pregnancies) and statins (13 per 10,000 pregnancies). Fetotoxic drugs were mainly non-steroidal anti-inflammatory drugs (NSAIDs), for systemic (128 per 10,000 pregnancies) and topical use (122 per 10,000 pregnancies). Exposure to teratogenic drugs decreased from the preconceptional period to the first trimester. Exposure to fetotoxic drugs decreased from the second to the third trimester. Between 2013 and 2019, we found a decrease in harmful drug exposure overall, mainly for topical and systemic NSAIDs and for topical retinoids.

CONCLUSIONS

In this nationwide study, about one in 25 pregnancies was exposed to at least one harmful drug, mainly NSAIDs and topical retinoids. Although the prevalence of harmful drug exposure decreased over the study period, NSAID exposure in the second and third trimester remains of concern.

Induction of Meiotic Initiation in Long-Term Mouse Spermatogonial Stem Cells Under Retinoid Acid and Nutrient Restriction Conditions

Spermatogonial stem cells (SSCs) produce haploid sperm via mitosis and meiosis in vivo. Although the technique to culture mouse SSCs has been well established, induction of meiosis in vitro has remained a challenge. Retinoic acid (RA) is required for meiosis in vivo; however, RA alone is not sufficient to induce meiosis in vitro. Here, we describe a method in which nutrient restriction and RA synergistically induce meiotic initiation into meiotic prophase I in cultured mouse SSCs.

Scavenging of Cation Radicals of the Visual Cycle Retinoids by Lutein, Zeaxanthin, Taurine, and Melanin

In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis, this study determined that the bimolecular rate constants of scavenging cation radicals of retinoids by taurine are smaller than 2 × 107 M-1s-1 whereas lutein scavenges cation radicals of all three retinoids with the bimolecular rate constants approach the diffusion-controlled limits, while zeaxanthin is only 1.4-1.6-fold less effective. Despite that lutein exhibits greater scavenging rate constants of retinoid cation radicals than other antioxidants, the greater concentrations of ascorbate in the retina suggest that ascorbate may be the main protectant of all visual cycle retinoids from oxidative degradation, while α-tocopherol may play a substantial role in the protection of retinaldehyde but is relatively inefficient in the protection of retinol or retinyl palmitate. While the protection of retinoids by lutein and zeaxanthin appears inefficient in the retinal periphery, it can be quite substantial in the macula. Although the determined rate constants of scavenging the cation radicals of retinol and retinaldehyde by dopa-melanin are relatively small, the high concentration of melanin in the RPE melanosomes suggests they can be scavenged if they are in proximity to melanin-containing pigment granules.

A Case of Noonan Syndrome and Kyrle Disease: Casualty or Causality?

A 39-year-old Caucasian woman affected by Noonan Syndrome (NS) mutated in RAF1 was referred to us with itchy lesions on her limbs that had appeared two months earlier. Clinically, there were multiple umbilicated papules with a hyperkeratotic central plug, localized on the upper and lower limbs (Figure 1, a-b). The patient had no personal history of diabetes mellitus or chronic renal failure, but suffered from hypertrophic cardiomyopathy. Blood tests showed no abnormalities. On histological examination of a skin lesion, an ectatic hair follicle with a hyperkeratotic ostium was observed with fragments of hair, inflammatory cells, and epidermal perforation. A final diagnosis of Kyrle disease (KD) was established. The patient underwent narrowband UVB (NB-UVB) phototherapy with residual atrophic scars (Figure 1, c-d), but with a complete and long-lasting resolution of symptoms. KD belongs to perforating dermatoses (PD), a heterogeneous group of skin diseases characterized by the transepidermal elimination of dermal components. Despite the classification of PD still being under debate, four primary forms are traditionally recognized: reactive perforating collagenosis, elastosis perforans serpiginosum, perforating folliculitis, and KD (1). The typical skin manifestation of KD is an eruption of dome-shaped papules and nodules, with a whitish central keratotic plug, mainly localized on the extremities and the buttocks. Described by Kyrle in 1916, KD is frequently associated with systemic diseases, especially chronic renal failure and diabetes mellitus. Other associated conditions include chronic hepatic disease, internal malignancies, and congestive heart disease (1). Despite the absence of a consensus, the control of the underlying disease remains the first therapeutic target. Both topical (keratolytics, retinoids, and corticosteroids) and systemic treatments (corticosteroids, retinoids, antibiotics, and phototherapy) have been reported to control skin manifestations (2). In our experience, NB-UVB is an effective option as first-line therapy in case of diffuse lesions, both in KD and in other PD (3). NS is a relatively common RASopathy, a heterogenous group of genetic diseases characterized by a defect of the Ras-mitogen-activated protein kinase (Ras-MAPK) pathway, with an estimated prevalence of 1/1000-2500. PTPN11 is the most frequent mutated gene, accounting for 50% of cases, but more than ten genes have been identified as causing NS (4). Classical features include a distinctive facial dysmorphism, short stature, pulmonic stenosis, and other anomalies of different organs. The skin is commonly involved. Keratinization disorders and hair abnormalities such as keratosis pilaris, ulerythema ophryogenes, wavy or curly hair, and scarce scalp hair, are often described. Other cutaneous signs include easy bruising, skin hyperlaxity, multiple lentigines, and café-au-lait spots (5). To the best of our knowledge, no cases of KD in patients with NS have been previously reported to date. The exact etiopathogenesis of KD is not clear, but it has been hypothesized that systemic diseases, such as diabetes and chronic renal failure, can cause a deposit of substances or dermis alterations, which triggers the inflammatory process with subsequent transepidermal extrusion (1). In our patient, we ruled out all the causes commonly associated with KD. It is however possible that this manifestation could be a direct result of the patient's illness. Our patient suffered from diffuse keratosis pilaris, and an abnormal epidermal keratinization with a secondary inflammatory dermic response is among the suggested possible pathogenetic mechanisms of KD (1). On the other hand, the hyperlaxity and fragility of the skin typical of NS suggest the presence of altered connective tissue, which could trigger an abnormal keratinization and, subsequently, the transepidermal extrusion, as well as perforating elastosis, which is associated with genetic connective tissue diseases (1). Moreover, our patient suffered from a cardiac disease, another condition associated with KD (5). Although these explanations have their appeal, there is currently insufficient evidence of a link between KD and NS, and it will be necessary to collect additional data to confirm this hypothesis.

Netrin-1 feedforward mechanism promotes pancreatic cancer liver metastasis via hepatic stellate cell activation, retinoid, and ELF3 signaling

The biology of metastatic pancreatic ductal adenocarcinoma (PDAC) is distinct from that of the primary tumor due to changes in cell plasticity governed by a distinct transcriptome. Therapeutic strategies that target this distinct biology are needed. We detect an upregulation of the neuronal axon guidance molecule Netrin-1 in PDAC liver metastases that signals through its dependence receptor (DR), uncoordinated-5b (Unc5b), to facilitate metastasis in vitro and in vivo. The mechanism of Netrin-1 induction involves a feedforward loop whereby Netrin-1 on the surface of PDAC-secreted extracellular vesicles prepares the metastatic niche by inducing hepatic stellate cell activation and retinoic acid secretion that in turn upregulates Netrin-1 in disseminated tumor cells via RAR/RXR and Elf3 signaling. While this mechanism promotes PDAC liver metastasis, it also identifies a therapeutic vulnerability, as it can be targeted using anti-Netrin-1 therapy to inhibit metastasis using the Unc5b DR cell death mechanism.

Anti-tumor activity of all-trans retinoic acid in gastric-cancer: gene-networks and molecular mechanisms

BACKGROUND

Gastric-cancer is a heterogeneous type of neoplastic disease and it lacks appropriate therapeutic options. There is an urgent need for the development of innovative pharmacological strategies, particularly in consideration of the potential stratified/personalized treatment of this tumor. All-Trans Retinoic-acid (ATRA) is one of the active metabolites of vitamin-A. This natural compound is the first example of clinically approved cyto-differentiating agent, being used in the treatment of acute promyelocytic leukemia. ATRA may have significant therapeutic potential also in the context of solid tumors, including gastric-cancer. The present study provides pre-clinical evidence supporting the use of ATRA in the treatment of gastric-cancer using high-throughput approaches.

METHODS

We evaluated the anti-proliferative action of ATRA in 27 gastric-cancer cell-lines and tissue-slice cultures from 13 gastric-cancer patients. We performed RNA-sequencing studies in 13 cell-lines exposed to ATRA. We used these and the gastric-cancer RNA-sequencing data of the TCGA/CCLE datasets to conduct multiple computational analyses.

RESULTS

Profiling of our large panel of gastric-cancer cell-lines for their quantitative response to the anti-proliferative effects of ATRA indicate that approximately half of the cell-lines are characterized by sensitivity to the retinoid. The constitutive transcriptomic profiles of these cell-lines permitted the construction of a model consisting of 42 genes, whose expression correlates with ATRA-sensitivity.  The model predicts that 45% of the TCGA gastric-cancers are sensitive to ATRA. RNA-sequencing studies performed in retinoid-treated gastric-cancer cell-lines provide insights into the gene-networks underlying ATRA anti-tumor activity. In addition, our data demonstrate that ATRA exerts significant immune-modulatory effects, which seem to be largely controlled by IRF1 up-regulation. Finally, we provide evidence of a feed-back loop between IRF1 and DHRS3, another gene which is up-regulated by ATRA.

CONCLUSIONS

ATRA is endowed with significant therapeutic potential in the stratified/personalized treatment gastric-cancer. Our data represent the fundaments for the design of clinical trials focusing on the use of ATRA in the personalized treatment of this heterogeneous tumor. Our gene-expression model will permit the development of a predictive tool for the selection of ATRA-sensitive gastric-cancer patients. The immune-regulatory responses activated by ATRA suggest that the retinoid and immune-checkpoint inhibitors constitute rational combinations for the management of gastric-cancer.

A Prospective, Multicenter, Study of Laser-Activated Gold Microparticles for Treating Patients Using Concomitant Topical Retinoids for Mild-to-Moderate Inflammatory Acne

Gold microparticles are indicated as an accessory to 1064 nm lasers to facilitate photo-thermal heating of sebaceous glands for treating mild-to-moderate inflammatory acne vulgaris (Sebacia Microparticles, Coronado Aesthetics LLC, Southlake, TX). The following study assessed the safety and clinical benefit of gold microparticles/laser therapy when used together with commercially available topical acne products. Healthy patients, 12 to 45 years old with mild-to-moderate inflammatory facial acne were prescribed a topical pre-treatment retinoid for 3 to 4 weeks. The gold microparticle suspension was then applied to the entire face and massaged into the skin. The laser procedure was performed with commercially available 1064 nm Nd:YAG lasers with fluence in the 20 to 35 J/cm2 range, a 30 ms pulse duration, and direct cooling. Among participants completing the study (N=52), the mean percent change in inflammatory lesion counts (ILC) was -55% at month 2, reaching -68% at month 12. At that time, 86% of participants achieved a 40% decrease in ILC and 75% achieved a 60% decrease in ILC. Mean Investigator's Global Assessment (IGA) Scale scores decreased by 41.6% from 2.4 at day 0 to 1.4 at month 12. The percentage of participants with clear or almost clear skin increased from 7% at day 0 to 59% at month 12. Acne therapy with topically applied gold microparticles followed by 1064 nm laser irradiation is an effective treatment for moderate to moderately severe acne. The treatment was well-tolerated with a high degree of participant satisfaction. J Drugs Dermatol. 2023;22(11):1088-1094     doi:10.36849/JDD.7744.

Mechanism of thyroid hormone and its structurally similar contaminant bisphenol S exposure on retinoid metabolism in zebrafish larval eyes

The photoreceptor necessitates the retinoids metabolism processes in visual cycle pathway to regenerate visual pigments and sustain vision. Bisphenol S (BPS), with similar structure of thyroid hormone (TH), was reported to impair the light-sensing function of zebrafish larvae via disturbing TH-thyroid hormone receptor β (TRβ) signaling pathway. However, it remains unknown whether TRβ could modulate the toxicity of BPS on retinoid metabolism in visual cycle. This study showed that BPS diminished the optokinetic response of zebrafish larvae and had a stimulative effect on all-trans-retinoic acid (atRA) metabolism, like exogenous T3 exposure. By modulating CYP26A1 and TRβ expression, it was found that CYP26A1 played a crucial role in catalyzing oxidative metabolism of atRA and retinoids regeneration in visual cycle, and TRβ mediated cyp26a1 expression in zebrafish eyes. Similar with 10 nM T3 treatment, cyp26a1 expression could be induced by BPS in the presence of TRβ. Further, in CYP26A1 and TRβ- deficient eyes, 100 μg/L BPS could no longer promote atRA metabolism, or decrease the all-trans-retinol and 11-cis retinal contents in visual cycle, demonstrating that BPS exposure disturbed CYP26A1-mediated visual retinoids metabolism via TRβ. Overall, this study highlights the role of TRβ in mediating the retinoids homeostasis disruption caused by BPS, and provides new clues for exploring molecular targets of visual toxicity under pollutants stress.

The apocarotenoid production in microbial biofactories: An overview

Carotenoids are a vast group of natural pigments that come in a variety of colors ranging from red to orange. Apocarotenoids are derived from these carotenoids, which are hormones, pigments, retinoids, and volatiles employed in the textiles, cosmetics, pharmaceutical, and food industries. Due to the high commercial value and poor natural host abundance, they are significantly undersupplied. Microbes like Saccharomyces cerevisiae and Escherichia coli act as heterologous hosts for apocarotenoid production. This article briefly reviews categories of apocarotenoids, their biosynthetic pathway commencing from the MVA and MEP, its significance, the tool enzymes for apocarotenoid biosynthesis like CCDs, their biotechnological production in microbial factories, and future perspectives.

Genome-Wide Association Studies to Drug: Identifying Retinoic Acid Metabolism Blocking Agents to Suppress Mechanoflammation in Osteoarthritis

Osteoarthritis (OA) is a highly prevalent debilitating joint disease for which there are currently no licensed disease-modifying treatments. The pathogenesis of OA is complex, involving genetic, mechanical, biochemical, and environmental factors. Cartilage injury, arguably the most important driving factor in OA development, is able to activate both protective and inflammatory pathways within the tissue. Recently, >100 genetic risk variants for OA have been identified through Genome Wide Association Studies, which provide a powerful tool to validate existing putative disease pathways and discover new ones. Using such an approach, hypomorphic variants within the aldehyde dehydrogenase 1 family member A2 (ALDH1A2) gene were shown to be associated with increased risk of severe hand OA. ALDH1A2 encodes the enzyme that synthesizes all-trans retinoic acid (atRA), an intracellular signaling molecule. This review summarizes the influence of the genetic variants on expression and function of ALDH1A2 in OA cartilage, its role in the mechanical injury response of cartilage, and its potent anti-inflammatory effect after cartilage injury. In doing so it identifies atRA metabolism-blocking agents as potential treatments for suppressing mechanoflammation in OA.

Dietary and plasma retinoids are not associated with fatty acid desaturase indices in healthy young adults

Past research in rodents suggests that fatty acid (FA) desaturase expression and activity may be modified by vitamin A; however, this has not been investigated in humans. The primary objective of this study was to examine associations between dietary retinoid intakes, plasma retinoid concentrations, and FA desaturase indices in young adults. As a secondary objective, biological sex and estrogen-containing contraceptive (EC) use were investigated due to prior evidence demonstrating that both can influence plasma retinol concentration and FA desaturase indices. Dietary retinoid intake (food frequency questionnaire), plasma retinoid concentrations (high-performance liquid chromatography-tandem mass spectrometry), plasma FA (gas chromatography), and FA desaturase indices (product-to-precursor ratios) from 945 adults recruited for the cross-sectional Toronto Nutrigenomics and Health study were analyzed. Participants were stratified into quartiles based on plasma retinol concentration and data analyzed by one-way analysis of covariance. Dietary retinoid intakes were not associated with the overall n-3 pathway, overall n-6 pathway, delta-5 desaturase, delta-6 desaturase, or delta-9 desaturase indices (all r < 0.10, p > 0.05). The overall n-6 pathway index was significantly higher (p = 0.0004) and the delta-5 desaturase index was significantly lower (p = 0.0003) in individuals with higher plasma retinol levels; however, these differences were lost when participants were grouped by biological sex and EC use. Although weak relationships were observed between plasma retinol and some FA desaturase indices in the total population, these associations appear to be driven by biological sex and EC usage rather than retinoids. We therefore find little evidence of a relationship between retinoids and FA desaturase indices in young, healthy adults.

Oral Isotretinoin and Its Uses in Dermatology: A Review

In 1982, the Food and Drug Administration (FDA) of the United States of America approved isotretinoin (13-cis-retinoic acid), a retinoid derivative of vitamin A, to treat severe recalcitrant acne vulgaris. Apart from its prescribed use for severe acne, evidence suggests that isotretinoin is commonly used off-label to treat mild-to-moderate acne, inflammatory skin conditions, genodermatoses, skin cancer, and other skin disorders. This is due to its anti-inflammatory, immunomodulatory, and antineoplastic properties. Some "off-label" use is successful, while others are ineffective. Therefore, this information is essential to clinicians for deciding on the appropriate use of isotretinoin. In this article, we aim to review the most updated evidence-based data about the use of oral isotretinoin in dermatology.

Impact of dietary vitamin A on striatal function in adult rats

The striatum is a brain structure involved in the control of voluntary movement. Striatum contains high amounts of retinoic acid, the active metabolite of vitamin A, as well as retinoid receptors, RARβ and RXRγ. Previous studies revealed that disruption of retinoid signaling initiated during development is deleterious for striatal physiology and related motor functions. However, the alteration of retinoid signaling, and the importance of vitamin A supply during adulthood on striatal physiology and function has never been established. In the present study, we investigated the impact of vitamin A supply on striatal function. Adult Sprague-Dawley rats were fed with three specific diets, either sub-deficient, sufficient, or enriched in vitamin A (0.4, 5, and 20 international units [IU] of retinol per g of diet, respectively) for 6 months. We first validated that vitamin A sub-deficient diet in adult rats constitutes a physiological model of retinoid signaling reduction in the striatum. We then revealed subtle alterations of fine motor skills in sub-deficient rats using a new behavioral apparatus specifically designed to test forepaw reach-and-grasp skills relying on striatal function. Finally, we showed using qPCR analysis and immunofluorescence that the striatal dopaminergic system per se was not affected by vitamin A sub-deficiency at adult age. Rather, cholinergic synthesis in the striatum and μ-opioid receptor expression in striosomes sub-territories were the most affected by vitamin A sub-deficiency starting at adulthood. Taken together these results revealed that retinoid signaling alteration at adulthood is associated with motor learning deficits together with discrete neurobiological alterations in the striatum.

Current management of generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare subset of psoriasis involving episodes of sterile pustules accompanied by inflammation and, often, systemic involvement. The inflammatory nature of GPP has potential for severe multisystem complications including high-output cardiac failure, infections, digestive system issues, and disfiguring or lethal acute flare episodes. The disease tends to have higher prevalence in females and Asians. The IL-1/IL-36 inflammatory pathway is a critical facet of GPP's pathology. Genetic mutations that are associated with GPP include modifications of Interleukin 36 Receptor Antagonist (IL36RN), Caspase Recruitment Domain Family Member 14 (CARD14), Adaptor Related Protein Complex 1 Subunit Sigma 3 (AP1S3), Myeloperoxidase (MPO) and Serpin Peptidase Inhibitor Clade A Member 3 (SERPINA3) genes. Treatment guidelines for GPP are not well-entrenched. Currently, only one GPP-specific treatment, the interleukin-36 receptor antagonist (IL-36Ra) spesolimab, has been approved for use in the United States. Additional anti-IL-36 pathway therapies are currently being developed. Other treatment options include other biologic therapies such as IL-17 inhibitors, IL-23 inhibitors and TNFα inhibitors. Non-biologic therapeutic options include retinoids, cyclosporine and methotrexate. Treatment options differ throughout the world; most countries utilize retinoids, cyclosporine and methotrexate as first-line non-biologic options. China and United Kingdom have no GPP-specific biologic therapies approved for use, while several biologic therapies are approved for use in Japan. This review aims to serve as an update on the current global management of GPP while also including relevant aspects of disease pathogenesis, diagnosis, clinical presentation, histopathology, aetiology and epidemiology.

Clinical and functional heterogeneity associated with the disruption of retinoic acid receptor beta

PURPOSE

Dominant variants in the retinoic acid receptor beta (RARB) gene underlie a syndromic form of microphthalmia, known as MCOPS12, which is associated with other birth anomalies and global developmental delay with spasticity and/or dystonia. Here, we report 25 affected individuals with 17 novel pathogenic or likely pathogenic variants in RARB. This study aims to characterize the functional impact of these variants and describe the clinical spectrum of MCOPS12.

METHODS

We used in vitro transcriptional assays and in silico structural analysis to assess the functional relevance of RARB variants in affecting the normal response to retinoids.

RESULTS

We found that all RARB variants tested in our assays exhibited either a gain-of-function or a loss-of-function activity. Loss-of-function variants disrupted RARB function through a dominant-negative effect, possibly by disrupting ligand binding and/or coactivators' recruitment. By reviewing clinical data from 52 affected individuals, we found that disruption of RARB is associated with a more variable phenotype than initially suspected, with the absence in some individuals of cardinal features of MCOPS12, such as developmental eye anomaly or motor impairment.

CONCLUSION

Our study indicates that pathogenic variants in RARB are functionally heterogeneous and associated with extensive clinical heterogeneity.

Retinol Saturase Mediates Retinoid Metabolism to Impair a Ferroptosis Defense System in Cancer Cells

Ferroptosis is an iron-dependent form of regulated cell death induced by the lethal overload of lipid peroxides in cellular membranes. In recent years, modulating ferroptosis has gained attention as a potential therapeutic approach for tumor suppression. In the current study, retinol saturase (RETSAT) was identified as a significant ferroptosis mediator using a publicly accessible CRISPR/Cas9 screening dataset. RETSAT depletion protected tumor cells from lipid peroxidation and subsequent cell death triggered by various ferroptosis inducers. Furthermore, exogenous supplementation with retinoids, including retinol (the substrate of RETSAT) and its derivatives retinal and retinoic acid, also suppressed ferroptosis, whereas the product of RETSAT, 13, 14-dihydroretinol, failed to do so. As effective radical-trapping antioxidant, retinoids protected the lipid membrane from autoxidation and subsequent fragmentation, thus terminating the cascade of ferroptosis. Pseudotargeted lipidomic analysis identified an association between retinoid regulation of ferroptosis and lipid metabolism. Retinoic acid, but not 13, 14-dihydroretinoic acid, interacted with its nuclear receptor and activated transcription of stearoyl-CoA desaturase, which introduces the first double bond into saturated fatty acid and thus catalyzes the generation of monounsaturated fatty acid, a known ferroptosis suppressor. Therefore, RETSAT promotes ferroptosis by transforming retinol to 13, 14-dihydroretinol, thereby turning a strong anti-ferroptosis regulator into a relatively weak one.

SIGNIFICANCE

Retinoids have ferroptosis-protective properties and can be metabolized by RETSAT to promote ferroptosis, suggesting the possibility of targeting retinoid metabolism in cancer as a treatment strategy to trigger ferroptosis.

RORing toward immunoregulation in glomerulonephritis?

CD4+ T cells that express forkhead box protein 3 are important in maintaining tolerance and restraining effector responses. Herrnstadt et al. use a model of rapidly progressive glomerulonephritis to examine the nature and role of forkhead box protein 3-positive and retinoid acid-related orphan receptor γt-positive regulatory T cells. These cells are prominent in experimental glomerulonephritis, both locally and systemically, and are present in kidneys of people with anti-neutrophil cytoplasmic antibody-associated vasculitis. Functionally, despite their expression of retinoid acid-related orphan receptor γt, associated with T-helper cell 17 cells, they regulate cellular immunity, both systemically and within the kidney.

Management of Acne Vulgaris With Trifarotene

Topical retinoids have an essential role in treatment of acne. Trifarotene, a topical retinoid selective for retinoic acid receptor (RAR) γ, is the most recent retinoid approved for treatment of acne. RAR-γ is the most common isoform of RARs in skin, and the strong selectivity of trifarotene for RAR-γ translates to efficacy in low concentration. Trifarotene, like other topical retinoids, acts by increasing keratinocyte differentiation and decreasing proliferation, which reduces hyperkeratinization. Retinoids have also been shown to inhibit inflammatory pathways via effects on leukocyte migration, toll-like receptors, and Activator Protein (AP)-1. Large-scale randomized, controlled clinical trials have demonstrated trifarotene to be safe, well tolerated, and efficacious in reducing both comedones and papules/pustules of acne. However, unlike all other retinoids, trifarotene is the first topical retinoid with rigorous clinical data on safety and efficacy in truncal acne. Data supporting use of trifarotene to manage acne are reviewed in this publication.

Multiple keratotic projections on the palms and soles

Spiny keratoderma (SKD) is a rare palmoplantar keratoderma that presents with few to numerous millimetric hyperkeratotic projections on the palms and soles. It has been described with both hereditary and acquired variants. The acquired form, which presents in older adults, has been associated with a variety of systemic diseases and malignant conditions. In patients suspected of having acquired spiny keratoderma, an evaluation for malignant conditions may be warranted. Treatment with topical keratolytics or topical and oral retinoids is usually insufficient. Herein, we present the case of a 58-year-old man diagnosed with idiopathic SKD.

Profiling cognitive-motor interference in a large sample of persons with progressive multiple sclerosis and impaired processing speed: results from the CogEx study

BACKGROUND

Performing cognitive-motor dual tasks (DTs) may result in reduced walking speed and cognitive performance. The effect in persons with progressive multiple sclerosis (pwPMS) having cognitive dysfunction is unknown.

OBJECTIVE

To profile DT-performance during walking in cognitively impaired pwPMS and examine DT-performance by disability level.

METHODS

Secondary analyses were conducted on baseline data from the CogEx-study. Participants, enrolled with Symbol Digit Modalities Test 1.282 standard deviations below normative value, performed a cognitive single task ([ST], alternating alphabet), motor ST (walking) and DT (both). Outcomes were number of correct answers on the alternating alphabet task, walking speed, and DT-cost (DTC: decline in performance relative to the ST). Outcomes were compared between EDSS subgroups (≤ 4, 4.5-5.5, ≥ 6). Spearman correlations were conducted between the DTCmotor with clinical measures. Adjusted significance level was 0.01.

RESULTS

Overall, participants (n = 307) walked slower and had fewer correct answers on the DT versus ST (both p < 0.001), with a DTCmotor of 15.8% and DTCcognitive of 2.7%. All three subgroups walked slower during the DT versus ST, with DTCmotor different from zero (p's < 0.001). Only the EDSS ≥ 6 group had fewer correct answers on the DT versus ST (p < 0.001), but the DTCcognitive did not differ from zero for any of the groups (p ≥ 0.039).

CONCLUSION

Dual tasking substantially affects walking performance in cognitively impaired pwPMS, to a similar degree for EDSS subgroups.

Sequential Treatment With Topical Trifarotene and Injectable NASHA Gel in Acne Scars: A Case Series

BACKGROUND

Topical retinoids are a mainstay in acne management and have been shown to improve skin texture. Injectable non-animal stabilized hyaluronic acid (NASHATM) gel as skin booster is largely used in aesthetic treatments to improve skin quality including the appearance of atrophic acne scars.

OBJECTIVE

To evaluate a new sequential treatment with topical trifarotene and injectable skin booster NASHA gel in acne scars.

METHODS

10 patients between 19 and 25 years (3 males and 7 females) with previous moderate to severe acne vulgaris on the face with the outcome of atrophic and post-inflammatory slightly hyperpigmented scars were prescribed home short contact therapy (SCT) with topical trifarotene 50 &mu;g/g at the evening for 3 months. A proper skincare routine for sensitive skin was also recommended. The 3-month retinoid therapy was followed by an injectable medical procedure with NASHA gel 20 mg/ml as skin booster. A minimum of 3 sessions to 10 sessions were carried out according to the severity of acne scars and the skin response observed.

RESULTS

Adherence to the treatment was complete and the results evaluated by digital photography showed very effective results with high clinical improvement or almost complete resolution of atrophic acne scars.

CONCLUSION

The results observed in this case series show that the sequential treatment with topical trifarotene and injectable NASHA gel as skin booster can be effective in the progressive reduction of acne scarring, potentially related to a synergic effect of skin remodeling and collagen stimulation. J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.7630.

Potential therapeutic role of melatonin in hepatobiliary diseases: current evidence and clinical observations

Melatonin (MEL) is produced and secreted by the pineal gland as well as the small intestine, liver, retina, lymphocytes, and melanocytes in the skin in both experimental animals as well as in humans. While pineal and retinas MEL is closely related to the light/dark cycle, the production of MEL by other so called extrapineal tissues is independent of such circadian rhythm. Among the primary mechanisms of action of MEL in humans, the most important are interaction of MEL with specific receptors (M1, M2, M3) and the MEL 'scavenging' activity against the formation of free oxygen metabolites as a result of MEL's ability to transfer free electrons and stimulation of the expression of redox reaction enzymes. In addition, MEL binds to intracellular proteins such as calmodulin, thereby affecting the course of cell cycle, and it has been shown to activate of nuclear receptors belonging to the retinoid orphan receptors/retinoid Z receptors (ROR/RZR) subfamily. MEL exerts regulatory effects on the master clock regulating diurnal rhythms. This updated review presents current view on the synthesis and metabolism of MEL and the growing body of experimental evidence transferable to the practical medicine supporting a pleiotropic molecule beneficial effects on the health including protection against various organ abnormalities, including internal organs such as the liver. Although the beneficial effects of MEL in various types of liver damage have been well documented in experimental studies, there are relatively few studies on liver dysfunction in humans. Considering the worldwide obesity pandemic often associated with the occurrence of steatohepatitis and cirrhosis, the beneficial effects of MEL in liver pathology should be proven in randomized trials involving patients presenting with hepatic disorders.

From mouse to human: Accessing the biochemistry of vision in vivo by two-photon excitation

The eye is an ideal organ for imaging by a multi-photon excitation approach, because ocular tissues such as the sclera, cornea, lens and neurosensory retina, are highly transparent to infrared (IR) light. The interface between the retina and the retinal pigment epithelium (RPE) is especially informative, because it reflects the health of the visual (retinoid) cycle and its changes in response to external stress, genetic manipulations, and drug treatments. Vitamin A-derived retinoids, like retinyl esters, are natural fluorophores that respond to multi-photon excitation with near IR light, bypassing the filter-like properties of the cornea, lens, and macular pigments. Also, during natural aging some retinoids form bisretinoids, like diretinoid-pyridiniumethanolamine (A2E), that are highly fluorescent. These bisretinoids appear to be elevated concurrently with aging. Vitamin A-derived retinoids and bisretinoidss are detected by two-photon ophthalmoscopy (2PO), using a new class of light sources with adjustable spatial, temporal, and spectral properties. Furthermore, the two-photon (2P) absorption of IR light by the visual pigments in rod and cone photoreceptors can initiate visual transduction by cis-trans isomerization of retinal, enabling parallel functional studies. Recently we overcame concerns about safety, data interpretation and complexity of the 2P-based instrumentation, the major roadblocks toward advancing this modality to the clinic. These imaging and retina-function assessment advancements have enabled us to conduct the first 2P studies with humans.

The retinoid metabolism of Gammarus fossarum is disrupted by exogenous all-trans retinoic acid, citral, and methoprene but not by the technical formulation of glyphosate

Over the last decade, fluctuations of retinoids (RETs), also known as vitamin A and derivatives, have proved to be useful biomarkers to assess the environmental chemical pressure on a wide variety of non-target vertebrates. This use of RET-based biomarkers is of particular interest in the non-target sentinel species Gammarus fossarum in which RETs were shown to influence crucial physiological functions. To study and probe this metabolism in this crustacean model, a UHPLC-MS/MS method was developed to 1) identify and 2) monitor several endogenous RETs in unexposed females throughout their reproductive cycle. Then, females were exposed in controlled conditions to exogenous all-trans retinoic acid (atRA) and citral (CIT), a RA synthesis inhibitor, to simulate an excess or deficiency in RA. Perturbation of vitamin A metabolism by pesticides was further studied in response to methoprene (MET), a juvenile hormone analog as well as glyphosate (GLY). The developed method allowed, for the first time in this model, the identification of RA metabolites (all-trans 4-oxo and 13-cis 4-oxo RA), RA isomers (all-trans and 13-cis RA) as well as retinaldehyde (RALD) isomers (all-trans, 11-cis, and 13-cis RALD) and showed two distinct phases in the reproductive cycle. Retinoic acid successfully increased the tissular concentration of both RA isomers and CIT proved to be efficient at perturbating the conversion from RALD to RA. Methoprene perturbed the ratios between RA isomers whereas GLY had no observed effects on the RET system of G. fossarum females. We were able to discriminate different dynamics of RET perturbations by morphogens (atRA or CIT) or MET which highlights the plausible mediation of RETs in MET-induced disorders. Ultimately, our study shows that RETs are influenced by exposure to MET and strengthen their potential to assess aquatic ecosystem chemical status.

Quantum chemistry rules retinoid biology

This Perspective discusses how retinol catalyzes resonance energy transfer (RET) reactions pivotally important for mitochondrial energy homeostasis by protein kinase C δ (PKCδ). PKCδ signals to the pyruvate dehydrogenase complex, controlling oxidative phosphorylation. The PKCδ-retinol complex reversibly responds to the redox potential of cytochrome c, that changes with the electron transfer chain workload. In contrast, the natural retinoid anhydroretinol irreversibly activates PKCδ. Its elongated conjugated-double-bond system limits the energy quantum absorbed by RET. Consequently, while capable of triggering the exergonic activating pathway, anhydroretinol fails to activate the endergonic silencing path, trapping PKCδ in the ON position and causing harmful levels of reactive oxygen species. However, physiological retinol levels displace anhydroretinol, buffer cyotoxicity and potentially render anhydroretinol useful for rapid energy generation. Intriguingly, apocarotenoids, the primary products of the mitochondrial β-carotene,9'-10'-oxygenase, have all the anhydroretinol-like features, including modulation of energy homeostasis. We predict significant conceptual advances to stem from further understanding of the retinoid-catalyzed RET.

Temporal changes in the systemic concentrations of retinoids in pregnant and postpartum women

Retinoids and vitamin A are essential for multiple biological functions, including vision and immune responses, as well as the development of an embryo during pregnancy. Despite its importance, alterations in retinoid homeostasis during normal human pregnancy are incompletely understood. We aimed to characterize the temporal changes in the systemic retinoid concentrations across pregnancy and postpartum period. Monthly blood samples were collected from twenty healthy pregnant women, and plasma concentrations of retinol, all-trans-retinoic acid (atRA), 13-cis-retinoic acid (13cisRA), and 4-oxo-retinoic acids were measured using liquid chromatography-tandem mass spectrometry. Significant decreases in 13cisRA concentrations over the pregnancy were observed, with rebound increases in retinol and 13cisRA levels after delivery. Of note, atRA concentrations exhibited a unique temporal pattern with levels peaking at mid-pregnancy. While the 4-oxo-atRA concentration was below the limit of quantification, 4-oxo-13cisRA was readily detectable, and its temporal change mimicked that of 13cisRA. The time profiles of atRA and 13cisRA remained similar after correction by albumin levels for plasma volume expansion adjustment. Together, the comprehensive profiling of systemic retinoid concentrations over the course of pregnancy provides insights into pregnancy-mediated changes in retinoid disposition to maintain its homeostasis.

Novel Therapeutic Potential of Retinoid-Related Orphan Receptor α in Cardiovascular Diseases

The retinoid-related orphan receptor α (RORα) is one subfamily of nuclear hormone receptors (NRs). This review summarizes the understanding and potential effects of RORα in the cardiovascular system and then analyzes current advances, limitations and challenges, and further strategy for RORα-related drugs in cardiovascular diseases. Besides regulating circadian rhythm, RORα also influences a wide range of physiological and pathological processes in the cardiovascular system, including atherosclerosis, hypoxia or ischemia, myocardial ischemia/reperfusion injury, diabetic cardiomyopathy, hypertension, and myocardial hypertrophy. In terms of mechanism, RORα was involved in the regulation of inflammation, apoptosis, autophagy, oxidative stress, endoplasmic reticulum (ER) stress, and mitochondrial function. Besides natural ligands for RORα, several synthetic RORα agonists or antagonists have been developed. This review mainly summarizes protective roles and possible mechanisms of RORα against cardiovascular diseases. However, there are also several limitations and challenges of current research on RORα, especially the difficulties on the transformability from the bench to the bedside. By the aid of multidisciplinary research, breakthrough progress on RORα-related drugs to combat cardiovascular disorder may appear.

Lipidomic Analysis of Geopropolis of Brazilian Stingless Bees by LC-HRMS

Stingless bees (Meliponini) represent over than 500 species, found in tropical and sub-tropical regions of the world. They produce geopropolis, a resinous natural product containing bioactive compounds, which is commonly used in folk medicine. In the current study, LC-HRMS and bioinformatic tools were used to carry out for the first time the lipidomic analysis of geopropolis from indigenous Brazilian stingless bees. As a result, 61 compounds of several lipid classes were identified with elevated degree of confidence. Then, we demonstrated that lipids in geopropolis are not restricted to waxes and fatty acids; but fatty amides and amines, phenolic lipids, resorcinols, retinoids, abietanoids, diterpenoids, pentacyclic triterpenoids, prostaglandins, retinoids, and steroids were found. In addition, multivariate analysis, based on the lipidomic profile of extracts, reinforces the assumption that the species of stingless bees, as well as the geographical origin are relevant factors to affect geopropolis composition once that the lipidic profile allowed the discrimination of geopropolis in groups related to the geographical origin, bee specie or bee genus. The lipidic profile also suggest a selective forage habits of T. angustula, which seems to collect resins from more specific vegetal sources regardless geographic origin, while other stingless bees, such as M. marginata and M. quadrifasciata, are less selective and may adapt to collect resins from a wider variety of plants.

The Amphipathic Helix in Visual Cycle Proteins: A Review

The visual cycle is a complex biological process that involves the sequential action of proteins in the retinal pigment epithelial (RPE) cells and photoreceptors to modify and shuttle visual retinoids. A majority of the visual cycle proteins are membrane proteins, either integral or peripheral membrane proteins. Despite significant progress in understanding their physiological function, very limited structural information is available for the visual cycle proteins. Moreover, the mechanism of membrane interaction is not yet clear in all cases. Here, we demonstrate the presence of an amphipathic helix in selected RPE visual cycle proteins, using in silico tools, and highlight their role in membrane association and function.

Toxicity, Genotoxicity, and Carcinogenicity of Isotretinoin

BACKGROUND

Acne is a chronic inflammatory disease mainly observed in adolescence, but it can also be seen during the neonatal, infantile, pre-pubertal, and adult periods. Isotretinoin (13-cis-retinoic acid) is a first-generation retinoid and is the most effective treatment for acne vulgaris.

OBJECTIVE

The present study has been systematically designed to figure out the toxic, genotoxic, and carcinogenic activities of isotretinoin.

METHODS

In this study, a systematic approach was followed by focusing on the possible links between these topics. The search of the databases was carried out author in accordance with the guidelines of the Centre for Reviews and Dissemination (2009) developed by York University National Institute of Health Research. The search was concentrated on the Web of Science, PubMed, Science Direct, Scopus, EBSCO Host, and Google Scholar databases.

RESULTS

Isotretinoin was found as a toxic agent in all studies. All researchers proposed that apoptosis is the only pathway of adverse effects of isotretinoin. However, genotoxicity, teratogenicity, and carcinogenicity information of isotretinoin is very limited and controversial.

CONCLUSION

More detailed studies need to clarify the genotoxic and carcinogenic potential of isotretinoin. Patients should be informed correctly, the risks of treatment should be explained, and awareness should be raised.

Estrogenic and retinoid-like activity in stagnant waters with mass occurrence of water blooms

Stagnant freshwaters can be affected by anthropogenic pollution and eutrophication that leads to massive growth of cyanobacteria and microalgae forming complex water blooms. These can produce various types of bioactive compounds, some of which may cause embryotoxicity, teratogenicity, endocrine disruption and impair animal or human health. This study focused on potential co-occurrence of estrogenic and retinoid-like activities in diverse stagnant freshwaters affected by phytoplankton blooms with varying taxonomic composition. Samples of phytoplankton bloom biomass and its surrounding water were collected from 17 independent stagnant water bodies in the Czech Republic and Hungary. Total estrogenic equivalents (EEQ) of the most potent samples reached up to 4.9 ng·g^-1 dry mass (dm) of biomass extract and 2.99 ng·L^-1 in surrounding water. Retinoic acid equivalent (REQ) measured by in vitro assay reached up to 3043 ng·g^-1 dm in phytoplankton biomass and 1202 ng·L^-1in surrounding water. Retinoid-like and estrogenic activities at some sites exceeded their PNEC and effect-based trigger values, respectively. The observed effects were not associated with any particular species of cyanobacteria or algae dominating the water blooms nor related to phytoplankton density. We found that taxonomically diverse phytoplankton communities can produce and release retinoid-like compounds to surrounding water, while estrogenic potency is likely related to estrogens of anthropogenic origin adsorbed to phytoplankton biomass. Retinoids occurring in water blooms are ubiquitous signalling molecules, which can affect development and neurogenesis. Selected water bloom samples (both water and biomass extracts) with retinoid-like activity caused effects on neurodifferentiation in vitro corresponding to those of equivalent all-trans-retinoic acid concentrations. Co-occurrence of estrogenic and retinoid-like activities in stagnant water bodies as well as the potential of compounds produced by water blooms to interfere with neural differentiation should be considered in the assessment of risks associated with water blooms, which can comprise complex mixtures of natural and anthropogenic bioactive compounds.

Environmentally relevant concentrations of F-53B induce eye development disorders-mediated locomotor behavior in zebrafish larvae

The perfluorooctane sulfonate alternative, F-53B, induces multiple physiological defects but whether it can disrupt eye development is unknown. We exposed zebrafish to F-53B at four different concentrations (0, 0.15, 1.5, and 15 μg/L) for 120 h post-fertilization (hpf). Locomotor behavior, neurotransmitters content, histopathological alterations, morphological changes, cell apoptosis, and retinoic acid signaling were studied. Histology and morphological analyses showed that F-53B induced pathological changes in lens and retina of larvae and eye size were significantly reduced as compared to control. Acridine orange (AO) staining revealed a dose-dependent increase in early apoptosis, accompanied by upregulation of p53, casp-9 and casp-3 genes. Genes related to retinoic acid signaling (aldh1a2), lens developmental (cryaa, crybb, crygn, and mipa) and retinal development (pax6, rx1, gant1, rho, opn1sw and opn1lw) were significantly downregulated. In addition, behavioral responses (swimming speed) were significantly increased, while no significant changes in the neurotransmitters (dopamine and acetylcholine) level were observed. Therefore, in this study we observed that exposure to F-53B inflicted histological and morphological changes in zebrafish larvae eye, induced visual motor dysfunctions, perturbed retinoid signaling and retinal development and ultimately triggering apoptosis.

Osteochondroma formation is independent of heparanase expression as revealed in a mouse model of hereditary multiple exostoses

Hereditary multiple exostoses (HME) is a rare, pediatric disorder characterized by osteochondromas that form along growth plates and provoke significant musculoskeletal problems. HME is caused by mutations in heparan sulfate (HS)-synthesizing enzymes EXT1 or EXT2. Seemingly paradoxically, osteochondromas were found to contain excessive extracellular heparanase (Hpse) that could further reduce HS levels and exacerbate pathogenesis. To test Hpse roles, we asked whether its ablation would protect against osteochondroma formation in a conditional HME model consisting of mice bearing floxed Ext1 alleles in Agr-CreER background (Ext1f/f ;Agr-CreER mice). Mice were crossed with a new global Hpse-null (Hpse-/- ) mice to produce compound Hpse-/- ;Ext1f/f ;Agr-CreER mice. Tamoxifen injection of standard juvenile Ext1f/f ;Agr-CreER mice elicited stochastic Ext1 ablation in growth plate and perichondrium, followed by osteochondroma formation, as revealed by microcomputed tomography and histochemistry. When we examined companion conditional Ext1-deficient mice lacking Hpse also, we detected no major decreases in osteochondroma number, skeletal distribution, and overall structure by the analytical criteria above. The Ext1 mutants used here closely mimic human HME pathogenesis, but have not been previously tested for responsiveness to treatments. To exclude some innate therapeutic resistance in this stochastic model, tamoxifen-injected Ext1f/f ;Agr-CreER mice were administered daily doses of the retinoid Palovarotene, previously shown to prevent ectopic cartilage and bone formation in other mouse disease models. This treatment did inhibit osteochondroma formation compared with vehicle-treated mice. Our data indicate that heparanase is not a major factor in osteochondroma initiation and accumulation in mice. Possible roles of heparanase upregulation in disease severity in patients are discussed.

Dynamic 3D Combinatorial Generation of hPSC-Derived Neuromesodermal Organoids With Diverse Regional and Cellular Identities

Neuromesodermal progenitors represent a unique, bipotent population of progenitors residing in the tail bud of the developing embryo, which give rise to the caudal spinal cord cell types of neuroectodermal lineage as well as the adjacent paraxial somite cell types of mesodermal origin. With the advent of stem cell technologies, including induced pluripotent stem cells (iPSCs), the modeling of rare genetic disorders can be accomplished in vitro to interrogate cell-type specific pathological mechanisms in human patient conditions. Stem cell-derived models of neuromesodermal progenitors have been accomplished by several developmental biology groups; however, most employ a 2D monolayer format that does not fully reflect the complexity of cellular differentiation in the developing embryo. This article presents a dynamic 3D combinatorial method to generate robust populations of human pluripotent stem cell-derived neuromesodermal organoids with multi-cellular fates and regional identities. By utilizing a dynamic 3D suspension format for the differentiation process, the organoids differentiated by following this protocol display a hallmark of embryonic development that involves a morphological elongation known as axial extension. Furthermore, by employing a combinatorial screening assay, we dissect essential pathways for optimally directing the patterning of pluripotent stem cells into neuromesodermal organoids. This protocol highlights the influence of timing, duration, and concentration of WNT and fibroblast growth factor (FGF) signaling pathways on enhancing early neuromesodermal identity, and later, downstream cell fate specification through combined synergies of retinoid signaling and sonic hedgehog activation. Finally, through robust inhibition of the Notch signaling pathway, this protocol accelerates the acquisition of terminal cell identities. This enhanced organoid model can serve as a powerful tool for studying normal developmental processes as well as investigating complex neurodevelopmental disorders, such as neural tube defects. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Robust generation of 3D hPSC-derived spheroid populations in dynamic motion settings Support Protocol 1: Pluronic F-127 reagent preparation and coating to generate low-attachment suspension culture dishes Basic Protocol 2: Enhanced specification of hPSCs into NMP organoids Support Protocol 2: Combinatorial pathway assay for NMP organoid protocol optimization Basic Protocol 3: Differentiation of NMP organoids along diverse cellular trajectories and accelerated terminal fate specification into neurons, neural crest, and sclerotome derivatives.

Tazarotene Lotion 0.045% for the Treatment of Acne

Topical retinoids are recommended as first line therapy for the treatment of acne. Despite this recommendation, topical retinoids are underutilized, in part because of their tendency to cause cutaneous irritation. Tazarotene 0.045% lotion was developed using polymeric emulsion technology to provide an effective, well tolerated topical retinoid for the treatment of acne.

Facial Aging Improvement Case Study Using a Novel Combination of Retinol, Niacinamide, and Terminalia Chebula

For decades, retinoids have been considered the gold standard of treatment for a variety of skin conditions.1,2 As the bioavailable form of vitamin A, retinoic acid has demonstrated the ability to reduce skin discoloration, stimulate collagen production, reduce rhytids, improve acne, and uneven skin texture.3,4 Retinoic acid is a potent drug with high bioavailability. Challenges with such a product include skin sensitivity and retinoid dermatitis.1,5 This potential irritation and discomfort may hinder patient compliance reducing visible results. The non-prescription vitamin A ingredient retinol is an effective and less irritating alternative, as it is converted into retinoic acid within the skin, causing little to no irritation when used topically. Intensive Age Refining Treatment: 0.5% pure retinol night by PCA SKIN&reg; contains 0.5% retinol, protected and delivered into the skin with a multi-layered liposomal delivery technology. This development addresses the inherent instability of retinol,1,2,3 as well as the mitigation of irritation with the goal of enhancing patient compliance and visible results. This formulation also features niacinamide and terminalia chebula to further support the anti-aging benefits of retinol. The 12-week in vivo use of this potent, yet non-irritating retinol topical demonstrates improved patient compliance and satisfaction due to tolerability and enhanced efficacy in the improvement in overall signs of healthy skin. J Drugs Dermatol. 2022;21(7):784-788. doi:10.36849/JDD.6621.

Identifying candidate reference chemicals for in vitro testing of the retinoid pathway for predictive developmental toxicity

Evaluating chemicals for potential in vivo toxicity based on their in vitro bioactivity profile is an important step toward animal- free testing. A compendium of reference chemicals and data describing their bioactivity on specific molecular targets, cellular pathways, and biological processes is needed to bolster confidence in the predictive value of in vitro hazard detection. Endogenous signaling by all-trans retinoic acid (ATRA) is an important pathway in developmental processes and toxicities. Employing data extraction methods and advanced literature extraction tools, we assembled a set of candidate reference chemicals with demonstrated activity on ten protein family targets in the retinoid system. The compendium was culled from Protein Data Bank, ChEMBL, ToxCast/Tox21, and the biomedical literature in PubMed. Finally, we performed a case study on one chemical in our collection, citral, an inhibitor of endogenous ATRA production, to determine whether the literature supports an adverse outcome pathway explaining the compound’s developmental toxicity initiated by disruption of the retinoid pathway. We also deliver an updated Abstract Sifter tool populated with these reference compounds and complex search terms designed to query the literature for the downstream consequences to support concordance with targeted retinoid pathway disruption.

In Vitro Rheology Predicts Improved Spreadability of Tazarotene 0.045% Lotion Versus Trifarotene 0.005% Cream

BACKGROUND

Intrinsic properties of vehicles used to deliver topical therapies can profoundly impact drug penetration, efficacy, patient acceptance, and treatment adherence. Therefore, advancements in vehicle technology demand sophisticated, quantitative approaches to describe and differentiate topical formulations. The objective of these studies was to quantitatively evaluate spreadability of two topical formulations for the treatment of acne via in vitro rheological measurement (how a substance&rsquo;s flow characteristics change under applied stress or force) and spreadability on living skin.

METHODS

Rheological characteristics (shear-thinning, rigidity, yield stress, and yield strain) of tazarotene 0.045% lotion and trifarotene 0.045% cream were measured using 5 samples of each product. In a clinical split-body study, each formulation was applied to one side of the back of healthy volunteers, and the extent to which each formulation could be spread was measured.

RESULTS

Compared to trifarotene cream, tazarotene lotion demonstrated lower mean viscosity, rigidity, and yield stress, and higher yield strain, suggesting a superior spreadability profile. This finding was confirmed in the split-body study of 30 healthy White adults, in which the average area of spread was significantly larger for tazarotene lotion than trifarotene cream (167.0 vs 130.3 cm2; P&lt;0.001).

CONCLUSIONS

Rheological assessment effectively predicted the superior spreadability of tazarotene 0.045% lotion versus trifarotene 0.005% cream on living skin. Given the importance of aesthetics of topical formulations, techniques to quantify these properties may have broad implications when developing novel vehicle formulations for dermatology. J Drugs Dermatol. 2022;21(3):250-257. doi:10.36849/JDD.6703.