Low concentration Phloxine B staining for high chemical contrast, nonlinear microscope mosaic imaging of skin alterations in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is an autosomal recessive metabolic disorder characterized by ectopic mineralization of soft connective tissue. Histopathology findings include fragmented, mineralized elastic fibers and calcium deposits in the mid-dermis. Nonlinear microscopy (NLM) can be used for visualization of these histopathological alterations of the mid-dermis in PXE-affected skin sections. Upon introducing a normalized 3D color vector representation of emission spectra of three of the main tissue components (collagen, elastin and calcification) we found that due to their broad, overlapping emission spectra, spectral separation of emission from elastin and calcification is practically impossible in fresh-frozen or unstained, deparaffinized PXE sections. However, we found that the application of a low concentration Phloxine B staining after the deparaffinization process creates an imaging contrast for these two tissue components, which enables spectral decomposition of their fluorescence images. The obtained concentration maps for calcium deposits can be well suited for the determination of illness severity by quantitative analysis.

Validity of EQ-5D-5L, Skindex-16, DLQI and DLQI-R in patients with hidradenitis suppurativa.

BACKGROUND: Numerous generic, skin- and disease-specific health-related quality of life (HRQoL) measures are available for patients with hidradenitis suppurativa (HS). Yet, robust psychometric evidence is lacking in many aspects of these outcome measures. OBJECTIVES: We sought to determine convergent and known-groups validity of multiple generic and skin-specific HRQoL measures and to identify predictors of impaired HRQoL in patients with HS. METHODS: Between 2017 and 2019, a multicentre cross-sectional study was carried out involving 200 consecutive HS patients. HRQoL outcomes included the EQ-5D-5L, EQ visual analogue scale (EQ VAS), Skindex-16, Dermatology Life Quality Index (DLQI) and DLQI-Relevant (DLQI-R). Disease severity was graded by HS-Physician's Global Assessment (HS-PGA) scale and the Modified Sartorius scale (MSS). RESULTS: Overall, 77%, 56%, 51%, 46% and 28% reported problems in the pain/discomfort, usual activities, anxiety/depression, mobility and self-care dimensions of EQ-5D-5L. Mean ± SD EQ VAS, DLQI and DLQI-R scores were 64.29 ± 22.68, 11.75 ± 8.11 and 12.19 ± 8.33, respectively. Skindex-16 responses indicated that the emotional burden of HS (64.55 ± 29.28) far exceeded those of functioning (49.40 ± 34.70) and physical symptoms (46.74 ± 29.36). EQ-5D-5L, EQ VAS, DLQI, DLQI-R and Skindex-16 total scores had moderate or strong correlations with each other (range: |0.487| to |0.993|), weak or moderate correlations with HS-PGA (|0.350| to |0.433|) and weak correlations with MSS (|0.324| to |0.389|). DLQI-R slightly outperformed DLQI both in terms of convergent and known-groups validity. Being female, lower education level, more severe disease and genital involvement were associated with worse HRQoL (P < 0.05). CONCLUSION: This study provides high-quality evidence that among skin-specific outcomes, the DLQI, DLQI-R and Skindex-16, and among generic instruments, the EQ-5D-5L are suitable to be used in HS patients. In future research, we recommend the use of existing well-validated HRQoL tools instead of developing new measures for each study. The development of composite measures that combine physician- and patient-reported outcomes is not supported by evidence in HS. [Correction added on 25 July 2020, after first online publication: in the Abstract section, the ± signs were missing and have been added to this version.].

Alopecia areata and health-related quality of life: a systematic review and meta-analysis.

BACKGROUND: No systematic review has yet evaluated the available evidence on health-related quality of life (HRQOL) in alopecia areata (AA). OBJECTIVES: To conduct a systematic review and meta-analysis of HRQOL studies among patients diagnosed with AA. METHODS: A systematic search was performed for papers published between 1946 and 15 December 2014 in Medline, Embase, Web of Science, CINAHL, PsycINFO and the Cochrane Library. Random-effects meta-analyses were conducted to pool data. RESULTS: Twenty-one studies were included, representing a total of 2530 adult patients with AA. Of the 14 different HRQOL measures used in the studies, Dermatology Life Quality Index (DLQI; n = 8) and SF-36 (n = 7) were the most common. Three AA-specific HRQOL instruments were identified: Alopecia Areata Quality of Life Index, Alopecia Areata Quality of Life and Alopecia Areata Symptom Impact Scale. The mean pooled DLQI score of patients with AA was 6·3 (95% confidence interval 5·6-7·1). Comparing age- and sex-matched controls, the meta-analysis of SF-36 studies revealed significantly reduced HRQOL across the role-emotional, mental health and vitality domains (P < 0·001). Wearing a wig had a positive impact, while scalp involvement, anxiety and depression had a negative impact on HRQOL. Conflicting results were found regarding the association between HRQOL and age, sex, marital status and disease duration. CONCLUSIONS: Patients with AA experience significant impairment in HRQOL, especially in the area of mental health. Several generic and dermatology-specific HRQOL instruments have been used, but no validation studies have confirmed their applicability in AA. The newly developed AA-specific measures seem very promising; however, a more extensive assessment of validity and reliability is needed.

PTCH codon 1315 polymorphism and risk for nonmelanoma skin cancer.

BACKGROUND: The PTCH tumour suppressor gene is involved in the development of nearly all basal cell carcinomas (BCCs) of the skin and a fraction of squamous cell carcinomas (SCCs). A nonconservative Pro/Leu nucleotide polymorphism within PTCH exon 23 at codon 1315 was recently reported to be potentially important for the development of breast epithelial cell cancers. Objectives Accordingly, the status of PTCH codon 1315 was analysed for a possible association with the development of nonmelanoma skin cancers (NMSCs) in a pilot study. Because skin cancer risk is affected by specific population-dependent phenotypes such as skin and hair colour, codon 1315 was also analysed for normal allele frequency variation in human populations having differing extents of eumelanin vs. phaeomelanin. METHODS: The single nucleotide polymorphism in codon 1315 of the human PTCH gene was analysed in genomic DNA from six different populations comprising 472 blood samples and from 170 patients in four different categories with NMSC. Polymerase chain reaction and pyrosequencing were used to determine the allele frequencies. Allelic loss was furthermore determined in tumours following microdissection. RESULTS: The Pro/Pro genotype frequency ranged from 30% to 65% between populations, with a significant trend for a reduced frequency of the Pro/Pro genotype in populations having lighter pigmentation (P = 0.020). Pro/Pro frequency showed an increasing trend with increasing tumour case severity (P = 0.027). In 260 samples from 180 Swedish patients with NMSC and a control group of 96 healthy ethnically matched volunteers, no statistically significant pairwise differences between groups were detected in the PTCH codon 1315 allelic distribution, neither was a difference seen for multiple or early onset cases of BCC in the Swedish population. In Swedish patients with single tumours, allelic loss (loss of heterozygosity) was observed in 20 of 30 (67%) patients with BCC and four of 22 (18%) patients with SCC, with no preference in the allele lost. In contrast, the Pro/Pro genotype was frequent in seven U.S. patients having multiple independent BCCs. One of these patients was heterozygous, enabling allelic loss studies. Of 20 independent tumours, 11 had lost an allele; 10 of the 11 had lost Leu, suggesting nonrandom loss that favoured retention of Pro (P = 0.0059). CONCLUSIONS: Our results indicate an association between the eumelanin-to-phaeomelanin shift and a shift from the Pro/Pro genotype to Leu-containing genotypes. Failure to lose Pro during the shift to phaeomelanin may be associated with an increased population risk for BCC and increased individual risk for multiple BCC. During development of a tumour, the effect of Pro may be magnified by loss of the Leu allele.

Escaping the stem cell compartment: sustained UVB exposure allows p53-mutant keratinocytes to colonize adjacent epidermal proliferating units without incurring additional mutations.

Once mutated, a single cell must expand into a clone before becoming significant for carcinogenesis. The forces driving clonal expansion and the obstacles that must be overcome are poorly understood. In a genetic mechanism, acquiring a second mutation conferring a proliferative advantage would enable the cell to expand autonomously. If carcinogen exposure instead induced a physiological change, clonal expansion would require the carcinogen's continued presence. To determine which is the case, we studied microscopic clones of keratinocytes mutated in the p53 tumor suppressor gene. Carcinogen exposure was controlled by irradiating mice with 280-320 nm UV radiation (UVB), sunlight's principal carcinogenic component; expansion of mutant clones was observed in epidermal sheets. p53-mutant clones grew only during chronic UVB exposure. Therefore, clonal expansion was not triggered by a proliferative mutation but was instead continually driven by UVB. Unexpectedly, the clone size distribution showed periodicity with maxima at estimated intervals of 16 +/- 6 cells, the size of the epidermal proliferating unit in murine dorsal skin. In the absence of UVB, rare "imprisoned clones" increased in cell number without increasing in area. We conclude that: stem cell compartments act as physical barriers to clonal expansion of a p53-mutant keratinocyte; a rate-limiting step in clonal expansion is the colonization of an adjacent compartment; and sustained UVB enables the p53-mutant keratinocyte to colonize without incurring an additional mutation.

The DNA damage signal for Mdm2 regulation, Trp53 induction, and sunburn cell formation in vivo originates from actively transcribed genes.

The stratum corneum and DNA repair do not completely protect keratinocytes from ultraviolet B. A third defense prevents cells with DNA photoproducts from becoming precancerous mutant cells: apoptosis of ultraviolet-damaged keratinocytes ("sunburn cells"). As signals for ultraviolet-induced apoptosis, some studies implicate DNA photoproducts in actively transcribed genes; other studies implicate non-nuclear signals. We traced and quantitated the in vivo DNA signal through several steps in the apoptosis-signaling pathway in haired mice. Homozygous inactivation of Xpa, Csb, or Xpc nucleotide excision repair genes directed the accumulation of DNA photoproducts to specific genome regions. Repair-defective Xpa-/- mice were 7-10-fold more sensitive to sunburn cell induction than wild-type mice, indicating that 86-90% of the ultraviolet B signal for keratinocyte apoptosis involved repairable photoproducts in DNA; the remainder involves unrepaired DNA lesions or nongenomic targets. Csb-/- mice, defective only in excising photoproducts from actively transcribed genes, were as sensitive as Xpa-/-, indicating that virtually all of the DNA signal originates from photoproducts in active genes. Conversely, Xpc-/- mice, defective in repairing the untranscribed majority of the genome, were as resistant to apoptosis as wild type. Sunburn cell formation requires the Trp53 tumor suppressor protein; 90-96% of the signal for its induction in vivo involved transcribed genes. Mdm2, which regulates the stability of Trp53 through degradation, was induced in vivo by low ultraviolet B doses but was suppressed at erythemal doses. DNA photoproducts in actively transcribed genes were involved in approximately 89% of the Mdm2 response.

Ultraviolet radiation induced signature mutations in photocarcinogenesis.

The photons of sunlight begin a series of genetic events in skin leading to cancer. UV signature mutations provide an alternative to inherited mutations as a way of identifying genes that are involved in cancer development. They augment epidemiologic and clinical data by serving as molecular evidence for the role of UV radiation in skin carcinogenesis. Signature mutations are present in TP53 and PTCH, two tumor suppressor genes responsible for non-melanoma skin cancer. We review evidence that clones of TP53-mutated cells are present in normal human and murine epidermis exposed to UVB and conclude that, in addition to being a tumorigenic mutagen, sunlight acts as a tumor promoter by favoring the clonal expansion of TP53 mutated cells. These combined actions of sunlight result in normal individuals' carrying a substantial burden of keratinocytes predisposed to cancer. Thus cancer involves both a single-cell problem and a multi-cell problem; in skin cancer, sunlight appears to drive both.

Induction of cyclin-dependent kinase inhibitors and G(1) prolongation by the chemopreventive agent N-acetylcysteine.

Cyclin-dependent kinase (cdk) inhibitors, such as p16(INK4a) and p21(WAF1/CIP1), often inhibit G(1) cyclin kinases and result in G(1) arrest. It has been suggested that p21(WAF1/CIP1) may also play a role in other chemopreventive activities such as DNA repair, slowdown of DNA replication and induction of cellular differentiation. In this report we demonstrate that the antioxidant N-acetylcysteine (NAC), a well-known chemopreventive agent, induces p16(INK4a) and p21(WAF1/CIP1) gene expression and prolongs cell-cycle transition through G(1) phase. A portion of the G(1) arrest by NAC is governed by p16(INK4a); it is independent of p53. NAC's usual mechanism of increasing intracellular glutathione level is not required for the G(1) arrest. An antioxidant whose action is limited to scavenging radicals, Trolox, does not induce G(1) arrest. Taken together, these results suggest a potential novel molecular basis for chemoprevention by NAC.

bcl-2 vs p53 protein expression and apoptotic rate in human nonmelanoma skin cancers.

BACKGROUND: A failure in the apoptotic response after severe genomic damage could facilitate cell transformation and tumor development, and a constitutive overexpression of either p53 or bcl-2 protein in nonapoptotic tumor cells could signify a defective bax-mediated apoptosis. OBJECTIVES: To investigate whether a negative correlation occurs between these 2 proteins in nonmelanoma skin cancer and whether overexpression of either protein is associated with a low rate of spontaneous apoptosis. DESIGN: Immunohistochemical study of nonmelanoma skin cancer archive material. SETTING: University referral center. PATIENTS: White patients with tumors on sun-exposed skin areas (ie, 17 basal cell carcinomas and 22 squamous cell carcinomas). MAIN OUTCOME MEASURES: Positivity for p53 and bcl-2 were scored semiquantitatively on 4 levels, and the percentages of apoptotic cells were determined. RESULTS: A significant negative correlation between p53 and bcl-2 expression was found in the basal cell carcinomas, but not in the squamous cell carcinomas, largely attributable to the low level of bcl-2 staining in the squamous cell carcinomas. Squamous cell carcinomas have a significantly higher number of apoptotic cells than basal cell carcinomas: 1.1% vs 0.6%, respectively. This spontaneous apoptosis decreases with increasing bcl-2 (in basal cell carcinoma), whereas it does not appear to be related to p53 level expression. CONCLUSIONS: These results indicate that a disturbance in either p53 or bcl-2 suffices to enhance skin tumor formation by suppressing apoptosis; bcl-2 appears to reduce the rate of spontaneous apoptosis, but an aberrant p53 expression does not, and this factor may solely affect the apoptosis from exogenous genotoxicity.

Disassembly of chromatin into approximately equal to 50 kb units by detergent.

Nuclei isolated from higher eukaryotic cell lines were directly analyzed by field inversion gel electrophoresis. Brief incubation of nuclei with ionic detergents yielded a single band between 50-100 kb. The apparent fragment size decreased to approximately equal to 50 kb after proteinase digestion. The latter treatment alone induced less regular, less than or equal to 50 kb fragmentation. DNA extracted from detergent and proteinase-treated nuclei also appeared in a band of about 40 kb. Embedding into agarose plugs did not protect nuclei, as opposed to cells, from detergent-induced fragmentation. The phenomenon is strikingly analogous to the double-strand DNA cleavage reactions mediated by topoisomerase II. Our data are compatible with any of the following interpretations: 1.) regularly spaced protein bridges, probably involving topoisomerase II, maintain or control continuity of chromosomal DNA in certain states of higher eukaryotic cells. 2.) The DNA might become accessible to a putative endonuclease at regularly spaced sites upon detergent treatment of isolated nuclei.