Morphological character of pseudoxanthoma elasticum observed by multiphoton microscopy

Autofluorescence Imaging of the Skin Is an Objective Non-Invasive Technique for Diagnosing Pseudoxanthoma Elasticum

Pseudoxanthoma elasticum (PXE) is a rare multisystemic autosomal recessive connective tissue disease. In most cases, skin manifestations of PXE are the first to develop, followed later by severe ocular and cardiovascular complications. In our present study, in addition to dermoscopy, we introduced novel techniques, autofluorescence (AF) and diffuse reflectance (DR) imaging for the assessment of affected skin sites of five PXE patients. PXE-affected skin areas in most skin sites showed a previously observed pattern upon dermoscopic examination. With the novel imaging, PXE-affected skin lesions displayed high AF intensity. During our measurements, significantly higher mean, minimum and maximum AF intensity values were found in areas of PXE-affected skin when compared to uninvolved skin. Conversely, images acquired with the use of 660 and 940 nm illumination showed no mentionable difference. Our results demonstrate that AF imaging may be used in the in vivo diagnostics and quantification of the severity of the skin lesions of PXE patients. In addition, it is a safe, fast and cost-effective diagnostic method. AF imaging may be also used to objectively monitor the efficacy of the possible novel therapeutic approaches of PXE in the future.

Nonlinear optical microscopy is a novel tool for the analysis of cutaneous alterations in pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE, OMIM 264800) is a rare autosomal recessive disorder with ectopic mineralization and fragmentation of elastin fibers. It is caused by mutations of the ABCC6 gene that leads to decreased serum levels of inorganic pyrophosphate (PPi) anti-mineralization factor. The occurrence of severe complications among PXE patients highlights the importance of early diagnosis so that prompt multidisciplinary care can be provided to patients. We aimed to examine dermal connective tissue with nonlinear optical (NLO) techniques, as collagen emits second-harmonic generation (SHG) signal, while elastin can be excited by two-photon excitation fluorescence (TPF). We performed molecular genetic analysis, ophthalmological and cardiovascular assessment, plasma PPi measurement, conventional histopathological examination, and ex vivo SHG and TPF imaging in five patients with PXE and five age- and gender-matched healthy controls. Pathological mutations including one new variant were found in the ABCC6 gene in all PXE patients and their plasma PPi level was significantly lower compared with controls. Degradation and mineralization of elastin fibers and extensive calcium deposition in the mid-dermis was visualized and quantified together with the alterations of the collagen structure in PXE. Our data suggests that NLO provides high-resolution imaging of the specific histopathological features of PXE-affected skin. In vivo NLO may be a promising tool in the assessment of PXE, promoting early diagnosis and follow-up.

Epidemiology and Treatment of Calcinosis Cutis: 13 Years of Experience

Background:

Calcinosis cutis is a rare condition associated with different diseases, which is difficult to manage.

Aims and Objectives:

In this retrospective study, the epidemiology of calcinosis cutis and the effectiveness of various treatment regimens in its management were assessed in a single center.

Materials and Methods:

The data of 34 patients suffering from calcinosis cutis (male:female = 12:22; mean age = 48.6 ± 18.6 years) treated at our department between 2003 and 2016 were analyzed retrospectively.

Results:

Dystrophic, idiopathic, metastatic subtype, and calciphylaxis occurred in 70.6%, 11.8%, 5.9%, and 11.8% of the cases, respectively. Underlying diseases of dystrophic calcinosis included autoimmune connective tissue disease, skin trauma, cutaneous neoplasm, and inherited disorder in 58.3%, 20.8%, 12.5%, and 8.3% of the cases, respectively. Extremities were most frequently affected (n = 18). In the management, diltiazem was most frequently used in monotherapy with partial response in five of eight cases. Other drugs in monotherapy or in combination were administered in single cases. Surgical treatment resulted in least partial response in all of the cases followed (n = 7).

Conclusion:

Dystrophic was the most common subtype and autoimmune connective tissue disease was the most frequent underlying disease. We conclude that lower doses of diltiazem have only partial efficiency, and surgical therapy is at least partially effective in localized calcinosis.

Ex vivo nonlinear microscopy imaging of Ehlers-Danlos syndrome-affected skin

Ehlers-Danlos syndrome (EDS) is the name for a heterogenous group of rare genetic connective tissue disorders with an overall incidence of 1 in 5000. The histological characteristics of EDS have been previously described in detail in the late 1970s and early 1980s. Since that time, the classification of EDS has undergone significant changes, yet the description of the histological features of collagen morphology in different EDS subtypes has endured the test of time. Nonlinear microscopy techniques can be utilized for non-invasive in vivo label-free imaging of the skin. Among these techniques, two-photon absorption fluorescence (TPF) microscopy can visualize endogenous fluorophores, such as elastin, while the morphology of collagen fibers can be assessed by second-harmonic generation (SHG) microscopy. In our present work, we performed TPF and SHG microscopy imaging on ex vivo skin samples of one patient with classical EDS and two patients with vascular EDS and two healthy controls. We detected irregular, loosely dispersed collagen fibers in a non-parallel arrangement in the dermis of the EDS patients, while as expected, there was no noticeable impairment in the elastin content. Based on further studies on a larger number of patients, in vivo nonlinear microscopic imaging could be utilized for the assessment of the skin status of EDS patients in the future.

Identification and functional characterization of a novel transglutaminase 1 gene mutation associated with autosomal recessive congenital ichthyosis

BACKGROUND

Autosomal recessive congenital ichthyosis (ARCI) is a group of genetically heterogeneous diseases. Mutations in transglutaminase (TGase) 1 gene (TGM1, OMIM 190195) have been implicated in ARCI. However, little is known about TGM1 mutations in the Chinese population, and no functional studies have investigated the biological effect of mutant TGM1 on human epidermal keratinocytes (HaCaT) cells.

OBJECTIVES

To identify the pathogenic mutations of TGM1 gene in two Chinese siblings with ARCI and gain insight into functional consequences of these mutations.

METHODS

Fifteen exons and flanking splice sites of TGM1 gene were amplified by polymerase chain reaction and then underwent bidirectional Sanger sequencing. The HaCaT cells were transfected with lentiviral vectors, which overexpressed either wild-type or mutant TGM1 cDNAs with deleted homeodomain. Cell proliferation and cell cycle progression were detected. The expression of cyclin D1, cyclin B1, CDK4, TGM1, K10, involucrin, and filaggrin proteins were investigated by Western blot analysis.

RESULTS

We found two compound heterozygous missense mutations (c.515C>T, R143C in exon 3 and c.759C>T, S212F in exon 4) in both siblings. HaCaT cells transfected with mutant TGM1 cDNAs displayed a lower growth rate and delayed S phase while overexpression of wild-type TGM1 cDNAs led to accelerated growth. HaCaT cells transfected with mutant TGM1 cDNAs displayed lower expression of differentiation markers such as involucrin and filaggrin. Our findings suggest that the compound heterozygous missense (c.515C>T, R143C) mutations in exon 3 and missense (c.759C>T, S212F) mutations in exon 4 result in the phenotype of ARCI. TGM1 mutations can suppress keratinocyte growth and cornified cell envelope formation.