Falk G. Bechara

What causes hidradenitis suppurativa

Abstract:  Hidradenitis suppurativa (HS) – a rather common, very chronic and debilitating inflammatory skin appendage disorder with a notoriously underestimated burden of disease – has long been a playground for the high priests of nomenclature: Ask a bunch of eminent dermatologists and skin pathologists to publicly share their thoughts on what causes HS, and they will soon get entrenched in a heated debate on whether this historical term is a despicable misnomer. Fortunately, the recently founded Hidradenitis Suppurativa Foundation (HSF; http://www.hs‐foundation.org), to which EXP DERMATOL serves as home journal, has broken with this unproductive tradition and has encouraged publication of the current CONTROVERSIES feature. This is exclusively devoted to discussing the pathobiology of this chronic neutrophilic folliculitis of unknown origin. Although traces of terminological bickering remain visible, it does the HS experts in our virtual debate room credit that they engage in a constructive and comprehensive dissection of potential pathogenesis pathways that may culminate in the clinical picture we know under the competing terms HS or acne inversa. These experts sketch more often complementary than mutually exclusive pathogenesis scenarios, and the outlines of a conceivable consensus on the many open pathobiology questions begin to emerge in these CONTROVERSIES. Hopefully, this heralds a welcome new tradition: to get to the molecular heart of HS pathogenesis, which can only be achieved by a renaissance of solid basic HS research, as the key to developing more effective HS therapy.

Histomorphologic correlation with routine histology and optical coherence tomography

Background: Optical coherence tomography (OCT) is a new and promising diagnostic technique for investigation of skin tumours. We describe a method that makes evaluation and definition of specific morphologic structures of skin tumours via OCT more accurate.

Expression of microRNAs in basal cell carcinoma

Background  Perturbations in the expression profiles of microRNAs (miRNAs) have been reported for a variety of different cancers. Differentially expressed miRNAs have not been systematically evaluated in basal cell carcinoma (BCC) of the skin.

MicroRNAs and the skin: Tiny players in the body's largest organ

MicroRNAs (miRNAs) are very small endogenous RNA molecules about 22-25 nucleotides in length, capable of post-transcriptional gene regulation. miRNAs bind to their target messenger RNAs (mRNAs), leading to cleavage or suppression of target mRNA translation based on the degree of complementarity. miRNAs have recently been shown to play pivotal roles in diverse developmental and cellular processes and linked to a variety of skin diseases and cancers. Disruption of miRNA metabolism is also involved in wound healing and inflammatory skin conditions. Here, we review the role of miRNAs in cutaneous biology.

Polymorphisms in NACHT‐LRR (NLR) genes in atopic dermatitis

Abstract:  Atopic dermatitis (AD) is a chronic skin disease affecting up to 15% of children in industrialized countries. AD belongs to the group of atopic disorders characterized by excessive immune reactions to ubiquitous antigens. Complex interactions between genetic and environmental factors have been suggested for atopic disorders. Dysregulation of the innate immune system appears crucial for the pathogenesis of AD. The NACHT‐LRRs (NLRs) represent a group of innate immune receptors with special relevance for inflammatory processes. In order to investigate the role of variation in NLR genes for AD, we genotyped 23 single nucleotide polymorphisms (SNPs) in seven selected NLR genes (CARD4, CARD15, CARD12, NALP1, NALP3, NALP12, MHC2TA) in 392 AD patients and 297 controls by restriction enzyme digestion or TaqMan assays. Single‐SNP analysis demonstrated significant associations of the CARD15_R702W variation and the NALP12_In9 T‐allele with AD (P = 0.008 and P = 0.03, resp.; insignificant after Bonferroni correction). In the CARD4 gene, a rare haplotype was more frequent in AD patients than in controls. Interactions between all pairs of SNPs in the seven genes were analysed by logistic regression. Significant interactions comprised SNPs in the CARD4 gene (CARD4_In1 and CARD4_Ex6, P = 6.56 × 10−7; CARD4_Prom und CARD4_Ex6, P = 2.45 × 10−4) and promoter polymorphisms in the CARD12 and NALP1 genes (P = 4.31 × 10−4). In conclusion, variation in individual genes from the NLR family as well as interactions within this group of innate immune receptor genes could play a role in AD pathogenesis. Investigations in other populations and functional studies are warranted to clarify contributions of NLR variation for this frequent skin disease.

Comparative microarray analysis of microRNA expression profiles in primary cutaneous malignant melanoma, cutaneous malignant melanoma metastases, and benign melanocytic nevi

Perturbations in microRNA (miRNA) expression profiles have been reported for cutaneous malignant melanoma (CMM) predominantly when examined in cell lines. Despite the rapidly growing number of newly discovered human miRNA sequences, the availability of up-to-date miRNA expression profiles for clinical samples of primary cutaneous malignant melanoma (PCMM), cutaneous malignant melanoma metastases (CMMM), and benign melanocytic nevi (BMN) is limited. Specimens excised from the center of tumors (lesional) from patients with PCMM (n=9), CMMM (n=4), or BMN (n=8) were obtained during surgery. An exploratory microarray analysis was performed by miRNA expression profiling based on Agilent platform screening for 1205 human miRNAs. The results from the microarray analysis were validated by TaqMan quantitative real-time polymerase chain reaction. In addition to several miRNAs previously known to be associated with CMM, 19 unidentified miRNA candidates were found to be dysregulated in CMM patient samples. Among the 19 novel miRNA candidates, the genes hsa-miR-22, hsa-miR-130b, hsa-miR-146b-5p, hsa-miR-223, hsa-miR-301a, hsa-miR-484, hsa-miR-663, hsa-miR-720, hsa-miR-1260, hsa-miR-1274a, hsa-miR-1274b, hsa-miR-3663-3p, hsa-miR-4281, and hsa-miR-4286 were upregulated, and the genes hsa-miR-24-1*, hsa-miR-26a, hsa-miR-4291, hsa-miR-4317, and hsa-miR-4324 were downregulated. The results of this study partially confirm previous CMM miRNA profiling studies identifying miRNAs that are dysregulated in CMM. However, we report several novel miRNA candidates in CMM tumors; these miRNA sequences require further validation and functional analysis to evaluate whether they play a role in the pathogenesis of CMM.

Expression levels of the microRNA maturing microprocessor complex component DGCR8 and the RNA-induced silencing complex (RISC) components argonaute-1, argonaute-2, PACT, TARBP1, and TARBP2 in epithelial skin cancer.

The microprocessor complex mediates intranuclear biogenesis of precursor microRNAs from the primary microRNA transcript. Extranuclear, mature microRNAs are incorporated into the RNA‐induced silencing complex (RISC) before interaction with complementary target mRNA leads to transcriptional repression or cleavage. In this study, we investigated the expression profiles of the microprocessor complex subunit DiGeorge syndrome critical region gene 8 (DGCR8) and the RISC components argonaute‐1 (AGO1), argonaute‐2 (AGO2), as well as double‐stranded RNA‐binding proteins PACT, TARBP1, and TARBP2 in epithelial skin cancer and its premalignant stage. Patients with premalignant actinic keratoses (AK, n = 6), basal cell carcinomas (BCC, n = 15), and squamous cell carcinomas (SCC, n = 7) were included in the study. Punch biopsies were harvested from the center of the tumors (lesional), from healthy skin sites (intraindividual controls), and from healthy skin sites in a healthy control group (n = 16; interindividual control). The DGCR8, AGO1, AGO2, PACT, TARBP1, and TARBP2 mRNA expression levels were detected by quantitative real‐time reverse transcriptase polymerase chain reaction. The DGCR8, AGO1, AGO2, PACT, and TARBP1 expression levels were significantly higher in the AK, BCC, and SCC groups than the healthy controls (P < 0.05). There was no significant difference in the TARBP2 expression levels between groups (P > 0.05). This study indicates that major components of the miRNA pathway, such as the microprocessor complex and RISC, are dysregulated in epithelial skin cancer.

Expression Levels of the microRNA Processing Enzymes Drosha and Dicer in Epithelial Skin Cancer

ABSTRACT Background: Dysregulation of microRNA (miRNA) metabolism has been observed in a variety of human cancers. In this pilot study, we investigated expression profiles of the two most important enzymes of the miRNA machinery, Drosha and Dicer, in relation to epithelial skin cancer and its premalignant stage. Methods: Patients with premalignant actinic keratoses (AK, n = 6), basal cell carcinomas (BCC, n = 15), and squamous cell carcinomas (SCC, n = 7) were included in the study. Punch biopsies were harvested from the center of the tumors (lesional) as well as from sites of healthy skin (intraindividual controls). Skin samples (n = 14) were also obtained from healthy subjects for additional controls. Dicer and Drosha mRNA levels were detected by quantitative real-time reverse transcriptase polymerase chain reaction. Results: Drosha expression levels were significantly upregulated in both the BCC and SCC groups compared to those in the healthy controls (p < .01), while Dicer expression levels in the BCC group were significantly lower (p < .05). Dicer expression in the SCC group was significantly higher compared to intraindividual controls (p < .05), while Dicer expression levels in both the SCC and AK groups were not significantly different from healthy control samples (p > .05). In the premalignant AK group, we could not observe any significant difference in Drosha or Dicer expression levels compared to either healthy or intraindividual controls (p > .05). Conclusions: We observed dysregulation of Drosha and Dicer expression in epithelial tumors when compared to healthy control samples. Therefore, we favor the hypothesis that miRNAs are involved in the carcinogenesis of epithelial skin cancer.

Microarray analysis of microRNA expression in cutaneous squamous cell carcinoma

BACKGROUND MicroRNAs (miRNAs) are a novel class of short RNAs that are capable epigenetically regulating gene expression in eukaryotes. MicroRNAs have been shown to be dysregulated in a variety of cancers. The data on miRNA expression in cutaneous squamous cell carcinoma (cSCC) are very limited, and microarray-based miRNA expression profiles of cSCC have not yet been determined. OBJECTIVE To describe differentially expressed miRNAs in cSCC. METHODS Seven patients with cSCC were enrolled in the present study. Tumor biopsies (n=7) were taken from the center of each tumor. Adjacent healthy skin (n=7) was biopsied as a control (intraindividual control). miRNA expression profiles of all specimens were detected by microarray miRNA expression profiling based on miRBAse 16 scanning for 1205 potential human miRNA target sequences. The microarray results were confirmed by TaqMan quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS Non-stringent filtering with a non-adjusted p ≤ 0.05 revealed thirteen up-regulated and eighteen down-regulated miRNAs. Non-stringent filtering with a non-adjusted p ≤ 0.01 revealed three up-regulated (hsa-miR-135b, hsa-miR-424 and hsa-miR-766) and six down-regulated (hsa-miR-30a*, hsa-miR-378, hsa-miR-145, hsa-miR-140-3p, hsa-miR-30a and hsa-miR-26a) miRNAs in cSCC. CONCLUSION This study reveals differentially expressed miRNAs that may play a role in the molecular pathogenesis of cSCC and that are excellent candidates for further validation and functional analysis.

Diagnostic value of hyperbilirubinemia as a predictive factor for appendiceal perforation in acute appendicitis

BACKGROUND Appendiceal perforation in patients with acute appendicitis may cause a variety of potentially life-threatening complications. Escherichia coli endotoxin has been shown to impact physiological bile flow in vivo. This had led to the theory that hyperbilirubinemia in patients with appendicitis may have a predictive potential for the preoperative diagnosis of appendiceal perforation. The aim of this retrospective study was to investigate the diagnostic value of hyperbilirubinemia as a preoperative laboratory marker for appendiceal perforation in patients with acute appendicitis. METHODS We identified 538 patients (306 female; 232 male, mean age, 35.6 y) with histologically proved acute appendicitis who underwent laparoscopic or conventional appendectomy between January 2004 and December 2007 in a surgical department of an academic teaching hospital. A retrospective multiple chart review of the medical records including laboratory values and histologic results was conducted. RESULTS The mean bilirubin level of all patients was .9 mg/dL (+/-.6 SD mg/dL; range, .1-4.3 mg/dL; median, .7 mg/dL). Patients with appendiceal perforation, however, had a mean bilirubin level of 1.5 mg/dL (+/-.9 SD mg/dL; range, .4-4.3 mg/dL; median, 1.4 mg/dL), which was significantly higher than those with a nonperforated appendicitis (P < .05). The specificity of hyperbilirubinemia for appendiceal perforation was .86 compared with .55 for white blood count and .35 for C-reactive protein. Sensitivity was .7 compared with .81 for white blood count and .96 for C-reactive protein. CONCLUSIONS Patients with hyperbilirubinemia and clinical symptoms of appendicitis should be identified as having a higher probability of appendiceal perforation than those with normal bilirubin levels.