Recalibrated Scales: The Use of Low-dose Isotretinoin in a Case of Epidermolytic Ichthyosis-NPS1 in a Filipino Child

Epidermolytic Ichthyosis (EI) is a rare non-syndromic keratinopathic ichthyosis without definitive treatment. This is a case of EI in a 5-year-old Filipino female who presented with hyperkeratotic scales sparing the palms and soles. Histopathology revealed epidermolytic hyperkeratosis. A trial of treatment with isotretinoin 0.3 mg/kg/day, together with keratolytic agents, urea lotion and lactic acid lotion, resulted in a marked decrease in the thickness of the scales and odor. Interestingly, rebound effects were noted at 0.6 mg/kg/day. Taking into account that EI presents with more skin fragility compared to non-EHK ichthyosis, the authors surmise that there may be a smaller treatment window for patients with EI, which is notably lower than recommended for ichthyosis in general.

Visualization of Keratin with Diffuse Reflectance and Autofluorescence Imaging and Nonlinear Optical Microscopy in a Rare Keratinopathic Ichthyosis

Keratins are one of the main fluorophores of the skin. Keratinization disorders can lead to alterations in the optical properties of the skin. We set out to investigate a rare form of keratinopathic ichthyosis caused by KRT1 mutation with two different optical imaging methods. We used a newly developed light emitting diode (LED) based device to analyze autofluorescence signal at 405 nm excitation and diffuse reflectance at 526 nm in vivo. Mean autofluorescence intensity of the hyperkeratotic palmar skin was markedly higher in comparison to the healthy control (162.35 vs. 51.14). To further assess the skin status, we examined samples from affected skin areas ex vivo by nonlinear optical microscopy. Two-photon excited fluorescence and second-harmonic generation can visualize epidermal keratin and dermal collagen, respectively. We were able to visualize the structure of the epidermis and other skin changes caused by abnormal keratin formation. Taken together, we were able to show that such imaging modalities are useful for the diagnosis and follow-up of keratinopathic diseases.

Cryptotanshinone from Salvia miltiorrhiza Roots Reduces Cytokeratin CK1/10 Expression in Keratinocytes by Activation of Peptidyl-prolyl-cis-trans-isomerase FKBP1A

Cryptotanshinone (CTS) (1 µM) from the roots of Salvia miltiorrhiza exerts a strong influence on the terminal differentiation of human keratinocytes (HaCaT cell line, primary natural human keratinocytes) and downregulates the expression of differentiation-specific cytokeratins CK1 and CK10 on protein and gene level. Other differentiation specific proteins as involucrin, filaggrin, loricrin, and transglutaminase were not affected to a higher extent. CTS (1 µM) did not influence the cell viability and the proliferation of keratinocytes. Using a combination of drug affinity response target stability assay in combination with a proteomic approach and multivariate statistics for target elucidation, peptidyl-prolyl-cis-trans-isomerase FKBP1A (known target of inhibitors such as tacrolimus or rapamycin) was addressed as potential molecular target of CTS. The interaction of CTS with FKBP1A was additionally shown by thermal shift and enzymatic activity assays. Interestingly, CTS served as an activator of FKBP1A, which led to a reduced activity of the TGFβ receptor pathway and therefore to a diminished CK1 and CK10 expression. The combination of the FKBP1A activator CTS with the inhibitor tacrolimus neutralized the effects of both compounds. From these data, a potential dermatological use of CTS and CTS-containing plant extracts (e.g., hydroalcoholic extract from the roots of S. miltiorrhiza) for keratinopathic ichthyosis, a disease characterized by overexpression of CK1 and CK10, is discussed. This study displays an experimental strategy for combining phytochemical aspects on active natural products with systematic identification of molecular targets on gene, protein, and cell level.