Isotretinoin: Still the cause of anxiety for teratogenicity

Face-to-face: isotretinoin use and pregnancy outcome

Isotretinoin has been used to treat severe acne for more than 40 years. There are no accurate data on the absolute risk of potential teratogenicity to all fetuses exposed to isotretinoin. According to current guidelines, isotretinoin should be discontinued at least 1 month before pregnancy. This study enrolled pregnant women who contacted the Clinical Pharmacology and Toxicology Unit for individual drug risk assessment between 2016 and 2020. Data on maternal characteristics and isotretinoin exposures were obtained at first consultation. After delivery, follow-up calls were conducted using a structured questionnaire. Of 2,323 pregnant women consulted, 1.3% (31/2,323) had systemic isotretinoin exposure during and before pregnancy. Of 31 prospectively followed pregnancies, eight terminated electively. Most elective terminations (7/8) were performed because of the fear of fetal malformation. The majority of continued pregnancies (16/23) resulted in healthy live birth. There were no major birth defects. In six pregnancies, intrauterine deaths (three first trimester, three second trimester) were reported. Cesarean section was performed in 70.5% (12/17) of all deliveries. The median gestational age at birth was 39, and no preterm births were reported. Local isotretinoin treatments in six cases were evaluated and presented additionally, and all babies were born healthy. Based on the results of this study, there was no evidence of major birth defect, mental disorder, or retinoid embryopathy associated with the use of isotretinoin in pregnancy. Not local use, but systemic exposure to isotretinoin is of great concern that results in pregnancy termination.

Assessment of the In Vivo Reprotoxicity of Isotretinoin in Sprague-Dawley Male Rat

BACKGROUND

Isotretinoin (ISO) belongs to a family of drugs called retinoids. It is the most effective drug prescribed by dermatologists for the treatment of the inflammatory disease, acne vulgaris. A significant barrier to the use of ISO has worries regarding its adverse effect profile. Despite the well-recognized reproductive toxicity and teratogenicity in females, there is no warning related to the use by male patients in the medication prospectus. Current data on the effects on human male fertility is contradictory and inconclusive.

OBJECTIVES

This study was undertaken to investigate the potential effects of ISO oral doses in the Sprague-Dawley male rat germ cells using the sperm morphology assay. Also, the serum levels of the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were measured.

METHODS

The rat groups were given varying ISO doses via gastric gavage for seven consecutive days. The epididymis sperm specimens were microscopically examined for the following reproductive toxicity parameters: sperm concentration, examined viability, motility, and morphology. The serum FSH, LH, and testosterone levels were measured by using the corresponding enzyme-linked immunosorbent assay (ELISA) kit. The data were analyzed statistically by one-way analysis of variance (ANOVA) followed by the Tukey test at P ≤ 0.05 significance level.

RESULTS

The results indicated that the drug did not significantly increase the sex hormone levels but notably affected both the sperm quantity and quality.

CONCLUSION

These observations suggest that ISO was reprotoxic, and future therapies should be further reassessed.

Alcohol induces neural tube defects by reducing retinoic acid signaling and promoting neural plate expansion

Introduction: Neural tube defects (NTDs) are among the most debilitating and common developmental defects in humans. The induction of NTDs has been attributed to abnormal folic acid (vitamin B9) metabolism, Wnt and BMP signaling, excess retinoic acid (RA), dietary components, environmental factors, and many others. In the present study we show that reduced RA signaling, including alcohol exposure, induces NTDs. Methods: Xenopus embryos were exposed to pharmacological RA biosynthesis inhibitors to study the induction of NTDs. Embryos were treated with DEAB, citral, or ethanol, all of which inhibit the biosynthesis of RA, or injected to overexpress Cyp26a1 to reduce RA. NTD induction was studied using neural plate and notochord markers together with morphological analysis. Expression of the neuroectodermal regulatory network and cell proliferation were analyzed to understand the morphological malformations of the neural plate. Results: Reducing RA signaling levels using retinaldehyde dehydrogenase inhibitors (ethanol, DEAB, and citral) or Cyp26a1-driven degradation efficiently induce NTDs. These NTDs can be rescued by providing precursors of RA. We mapped this RA requirement to early gastrula stages during the induction of neural plate precursors. This reduced RA signaling results in abnormal expression of neural network genes, including the neural plate stem cell maintenance genes, geminin, and foxd4l1.1. This abnormal expression of neural network genes results in increased proliferation of neural precursors giving rise to an expanded neural plate. Conclusion: We show that RA signaling is required for neural tube closure during embryogenesis. RA signaling plays a very early role in the regulation of proliferation and differentiation of the neural plate soon after the induction of neural progenitors during gastrulation. RA signaling disruption leads to the induction of NTDs through the mis regulation of the early neuroectodermal network, leading to increased proliferation resulting in the expansion of the neural plate. Ethanol exposure induces NTDs through this mechanism involving reduced RA levels.

Efficacy and safety of low-level light therapy by delicate pulsed light combined with low-dose oral isotretinoin for the treatment of acne vulgaris: a randomized split-face study

Acne vulgaris (AV) is a common dermatosis that causes psychological problems. Isotretinoin is the first-line treatment for moderate-to-severe AV, but its onset of effect is delayed. Although light-based therapy is widely used in the treatment of AV, there is a lack of reports on delicate pulsed light (DPL) which has a narrow therapeutic spectrum (500-600 nm). Low-level light therapy (LLLT) has shown an emerging role in anti-inflammatory effects and skin repair. This study investigates the efficacy and safety of low-dose oral isotretinoin combined with LLLT using DPL in patients with moderate-to-severe AV. Thirty-six patients with moderate-to-severe AV were enrolled and received low-dose oral isotretinoin (10-20 mg/day). The two sides of the face were randomly assigned to receive DPL (6-9 J/cm²) or not at an interval of 2 weeks for 4 treatment sessions (weeks 0, 2, 4, 6). Photos, GAGS score, counts of papules, pustules, comedones, TEWL, melanin and erythema index, side effects, efficacy, and satisfactory score were recorded at each visit and at 4 weeks after the final treatment (week 10). Thirty-three patients completed the study. DPL and oral isotretinoin combined therapy exhibited significantly improved GAGS score as well as the number of the lesions from week 2 and maintained until week 10. At the end of the observation, the improvement of GAGS was 70.88% on the DPL and isotretinoin combined side versus 62.12% on the side with isotretinoin monotherapy (p = 0.0009). The improvement for papule number was 61.58% on the DPL combined side versus 43.33% on the control side (p < 0.0001), for comedone was 63.15% versus 43.30% (p = 0.0008). TEWL and indexes of melanin and erythema also had better outcomes with DPL combined therapy at week 10. All the side effects were temporary and tolerable; no adverse effects were observed. Oral low-dose isotretinoin combined with LLLT by DPL offers a combination with reduced side effects and better outcomes within a limited treatment duration, which advances the onset of effect of isotretinoin monotherapy and improves lesion clearance.

Alopecia areata and isotretinoin; coincidence or causal relation

Isotretinoin is a safe and useful medication for acne management. Adverse effects are mostly related to cutaneous and mucous membranes. We present a case of a 24-year-old female patient who was on treatment with isotretinoin for acne vulgaris Grade 4. After 6 months of treatment, the patient presented with localized patch of hair loss. Beginning of alopecia areata in patients with acne vulgaris could be regarded as a side effect of retinoids due to anti-acne therapy. The exact mechanism by which retinoids cause hair loss is not known.