Clinical and histopathological aspects of the most common inflammatory non-infectious skin diseases.

The authors present a didactic overview of the most common inflammatory non-infectious skin diseases. This overview is not exhaustive, but illustrative, especially when regarding the aspect of a systematic approach to the evaluation of skin biopsy with an initial evaluation of the morphological pattern of the inflammatory process. This will subsequently facilitate the diagnosis. Photodocumentation of typical primary skin manifestations is attached to the photomicrograph images. This enables the pathologist to make a basic clinical-pathological correlation, which is of fundamental importance in dermatopathology.

Diagnostic Pitfalls in Dermatopathology.

Dermatopathology is a distinct part of pathology revealing the rich association with soft tissue pathology and hematopathology. Regarding the number and diversity of the skin disorders, dermatopathology is a broad specialty encompassing hundreds of diseases. The diagnostics in dermatopathology contains a range of specific features. The article summarizes several practically important pitfalls in dermatopathology. The adequate timing and locality selection for proper sampling are emphasized. The influence of the topical therapy on the histopathological picture is debated. The frequently used surgical procedures in the skin biopsy are presented. The most frequent incidental findings and artifacts in cutaneous pathology are discussed. Problematics of the alopecia examination and direct immunofluorescence are added. Clinical-pathological correlation performed by the pathologist, and subsequently by the dermatologist, is the essential step in the diagnostic process. The knowledge transcending to the other specialty and reciprocal communication are prerequisite for the right diagnosis.

Stevens-Johnson syndrome and toxic epidermal necrolysis from pathologist's point of view.

Stevens-Johnson syndrome and toxic epidermal necrolysis (Lyell syndrome) are rare diseases characterized by rapid blistering followed by extensive skin and mucosal exfoliation and constitutional symptoms. In most cases, drugs are the main triggers, but the etiopathogenesis of the diseases is not fully understood. Lyell syndrome is associated with a high mortality rate, reported to be around 35%. Therefore, early diagnosis requiring close interdisciplinary cooperation is essential. The diagnosis based on the clinical picture and a detailed pharmacological history should be confirmed by histopathological examination of the skin specimen, including analysis by direct immunofluorescence.

A case of cutaneous collagenous vasculopathy associated with multiple myeloma and with a pathogenic variant of the glucocerebrosidase gene.

Cutaneous collagenous vasculopathy (CCV) is an extremely rare acquired microangiopathy of unknown etiology. The authors describe a case of a 68-year-old man, a carrier of a heterozygous pathogenic variant of the glucocerebrosidase (GBA) gene, who was diagnosed with CCV, revealing uncommon fibrinogen positivity in direct immunofluorescence. The patient was subsequently diagnosed with multiple myeloma. Treatment of the myeloma with combined chemotherapy including bortezomib, followed by autologous stem cell transplantation, led to significant reduction of cutaneous lesions. To the best of the authors' knowledge, this is the first published case of CCV in a carrier of a pathogenic variant of the GBA gene, associated with multiple myeloma and with significant regression of CCV after myeloma treatment. Direct immunofluorescence examination revealed an unusual fibrinogen deposition. Hypothetical causative role of bortezomib treatment was proposed regarding significant regression of CCV.

A comprehensive evaluation of pathogenic mutations in primary cutaneous melanomas, including the identification of novel loss-of-function variants.

The most common histological subtypes of cutaneous melanoma include superficial spreading and nodular melanoma. However, the spectrum of somatic mutations developed in those lesions and all potential druggable targets have not yet been fully elucidated. We present the results of a sequence capture NGS analysis of 114 primary nodular and superficial spreading melanomas identifying driver mutations using biostatistical, immunohistochemical and/or functional approach. The spectrum and frequency of pathogenic or likely pathogenic variants were identified across 54 evaluated genes, including 59 novel mutations, and the newly identified TP53 loss-of-function mutations p.(L194P) and p.(R280K). Frequently mutated genes most commonly affected the MAPK pathway, followed by chromatin remodeling, and cell cycle regulation. Frequent aberrations were also detected in the genes coding for proteins involved in DNA repair and the regulation and modification of cellular tight junctions. Furthermore, relatively frequent mutations were described in KDR and MET, which represent potential clinically important targets. Those results suggest that with the development of new therapeutic possibilities, not only BRAF testing, but complex molecular testing of cutaneous melanoma may become an integral part of the decision process concerning the treatment of patients with melanoma.

Expression of Glut-1 in Malignant Melanoma and Melanocytic Nevi: an Immunohistochemical Study of 400 Cases.

The glucose transporter-1 (Glut-1) is a cell membrane glycoprotein involved in glucose uptake. An increased expression of Glut-1 is an important cell adaptation mechanism against hypoxia. An upregulation of Glut-1 can be found in several types of malignant tumors, which are able to reprogram their metabolism from oxidative phosphorylation to aerobic glycolysis (Warburg effect). However, the data regarding melanocytic lesions is equivocal. We performed comprehensive immunohistochemical analysis of the Glut-1 expression in 225 malignant melanomas (MM) and 175 benign nevi. Only the membranous expression of Glut-1 was regarded as positive. The expression of Glut-1 (the cut-off for positivity was determined as H-score 15) was found in 69/225 malignant melanomas. The number of positive cases and the H-score of Glut-1 increased where there was a higher Breslow thickness (p < 0.00001) when comparing pT1- pT4 MM groups. All benign nevi were classified as negative. In conclusion, the membranous expression of Glut-1 is a common feature of a malignant melanoma but this type of expression is very rare in benign melanocytic nevi. Our results suggest that the membranous expression of Glut-1 can be used as a surrogate marker in the assessing of the biological nature of benign and malignant melanocytic lesions. However, despite its high specificity, the sensitivity of this marker is relatively low. Moreover, due to the fact that the increased expression of Glut-1 correlates with a shorter survival period (10-year disease free survival, recurrence free survival and metastasis free survival and MFS), it can be used as a prognostically adverse factor.

Comparison of five different scoring methods in the evaluation of inflammatory infiltration (tumor-infiltrating lymphocytes) in superficial spreading and nodular melanoma.

The objective of our study was to compare the five different scoring methods of tumor-infiltrating lymphocytes (TILs) assessment in a group of 213 cases of superficial spreading and nodular melanoma. The scoring methods include (a) Clark scoring; (b) Melanoma Institute Australia system; (c) scoring system used in the study of Saldanha et al.; (d) scoring system used in the TCGA study and modified by Park et al.; and (e) the system recently proposed by the "International Immuno-Oncology Biomarker Working Group" for TILs scoring in all solid tumors. Prediction of survival with three main outcomes-disease-specific-free survival, local recurrence-free survival, and distant metastasis-free survival-was evaluated. The prognostic value of TILs showed statistical significance in univariate analysis regarding all three of the outcomes only for three of the five evaluated methods; the Clark scoring, the Melanoma Institute Australia system, and the system proposed by the "International Immuno-Oncology Biomarker Working Group". However, in multivariate analysis with covariants including Breslow thickness, type of melanoma, location, sex, and age, we did not find TILs to be an independent prognostic factor.

Expression of Glut-1 in Normal Endometrium and Endometrial Lesions: Analysis of 336 Cases.

BACKGROUND: Glucose transporter-1 (Glut-1) is a membrane glycoprotein that is, together with other glucose transporters, responsible for the regulation of glucose uptake. An increased expression of this protein seems to be a general feature of several malignant tumors that are able to reprogram their metabolism and switch from oxidative phosphorylation to aerobic glycolysis. METHODS: We performed comprehensive immunohistochemical analysis of Glut-1 expression in 336 endometrial samples, including tumors, nontumor lesions, and normal tissues. RESULTS: Expression of Glut-1 was found in 87% of endometrioid carcinomas (160/184 cases), 100% of serous carcinomas (29/29 cases), 100% of clear cell carcinomas (17/17 cases), 50% of polyps with atypical hyperplasia (8/16 cases), 12.5% of polyps with non-atypical hyperplasia (3/24 cases), 77% of hyperplasias with atypias (10/13 cases), 9% of hyperplasias without atypias (1/11 cases), 87% of secretory endometrium samples (13/15 cases), and in none of the nonsecretory endometrium samples (0/27 cases). In endometrioid carcinomas, Glut-1 was expressed in a marked geographical pattern. In nontumor lesions, its expression was more common in atypical hyperplasia and polyps with atypical hyperplasia compared with polyps with non-atypical hyperplasia and hyperplasias without atypia ( P = .00032). CONCLUSION: Our study confirms the high expression of Glut-1 not only in endometrioid carcinomas but also in other carcinomas of endometrium including clear cell and serous types. Glut-1 expression can be used as a surrogate marker in differential diagnosis between hyperplasia with and without atypia. Because of common Glut-1 expression in malignant tumors, therapeutic strategies influencing this protein or its signaling pathways can be beneficial.

Axial tubule junctions control rapid calcium signaling in atria.

The canonical atrial myocyte (AM) is characterized by sparse transverse tubule (TT) invaginations and slow intracellular Ca2+ propagation but exhibits rapid contractile activation that is susceptible to loss of function during hypertrophic remodeling. Here, we have identified a membrane structure and Ca2+-signaling complex that may enhance the speed of atrial contraction independently of phospholamban regulation. This axial couplon was observed in human and mouse atria and is composed of voluminous axial tubules (ATs) with extensive junctions to the sarcoplasmic reticulum (SR) that include ryanodine receptor 2 (RyR2) clusters. In mouse AM, AT structures triggered Ca2+ release from the SR approximately 2 times faster at the AM center than at the surface. Rapid Ca2+ release correlated with colocalization of highly phosphorylated RyR2 clusters at AT-SR junctions and earlier, more rapid shortening of central sarcomeres. In contrast, mice expressing phosphorylation-incompetent RyR2 displayed depressed AM sarcomere shortening and reduced in vivo atrial contractile function. Moreover, left atrial hypertrophy led to AT proliferation, with a marked increase in the highly phosphorylated RyR2-pS2808 cluster fraction, thereby maintaining cytosolic Ca2+ signaling despite decreases in RyR2 cluster density and RyR2 protein expression. AT couplon "super-hubs" thus underlie faster excitation-contraction coupling in health as well as hypertrophic compensatory adaptation and represent a structural and metabolic mechanism that may contribute to contractile dysfunction and arrhythmias.

Comparison of immunohistochemistry, four in situ hybridization methods and quantitative polymerase chain reaction for the molecular diagnosis of HER2 status in gastric cancer: a study of 55 cases.

In the current study, the sensitivity and specificity of methods of HER2 status detection were studied in 55 patients presenting with gastric/gastroesophageal junction carcinoma (30 intestinal and 25 diffuse), in small biopsy (endoscopy; n=33) and resection specimens (n=22). The primary objective of the present study was to compare various methods for the assessment of HER2 status, with regards to the sensitivity and specificity of each method, as well as their concordance. In all cases, the status of HER2 was determined using immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), silver in situ hybridization (SISH), and quantitative polymerase chain reaction (qPCR). The concordance rate between IHC and ISH was 100% for IHC 0 and 3+. The concordance rate for IHC 1+ was 100% between IHC and SISH, and 92.9% between IHC and FISH. The concordance rate among different FISH methods was 100%, between FISH and SISH it was 96.2%, and between qPCR and ISH methods it was 88.5%. Thus, the results demonstrate that different in situ hybridization methods are comparable and that none were superior. Furthermore, the IHC and FISH methods were found to be comparable and the concordance rate was particularly good. qPCR analysis correlated well with the other methods and appears to be a possible alternative tool for detection of the HER2 status. However, the concordance rate of qPCR with other methods was identified to be lower in the diffuse carcinoma group of endoscopy biopsy specimens; therefore investigation of further cases is required.

Toward panoramic in situ mapping of action potential propagation in transgenic hearts to investigate initiation and therapeutic control of arrhythmias.

To investigate the dynamics and propensity for arrhythmias in intact transgenic hearts comprehensively, optical strategies for panoramic fluorescence imaging of action potential (AP) propagation are essential. In particular, mechanism-oriented molecular studies usually depend on transgenic mouse hearts of only a few millimeters in size. Furthermore, the temporal scales of the mouse heart remain a challenge for panoramic fluorescence imaging with heart rates ranging from 200 min(-1) (e.g., depressed sinus node function) to over 1200 min(-1) during fast arrhythmias. To meet these challenging demands, we and others developed physiologically relevant mouse models and characterized their hearts with planar AP mapping. Here, we summarize the progress toward panoramic fluorescence imaging and its prospects for the mouse heart. In general, several high-resolution cameras are synchronized and geometrically arranged for panoramic voltage mapping and the surface and blood vessel anatomy documented through image segmentation and heart surface reconstruction. We expect that panoramic voltage imaging will lead to novel insights about molecular arrhythmia mechanisms through quantitative strategies and organ-representative analysis of intact mouse hearts.

A novel ryanodine receptor mutation linked to sudden death increases sensitivity to cytosolic calcium.

RATIONALE: Mutations in the cardiac type 2 ryanodine receptor (RyR2) have been linked to catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT-associated RyR2 mutations cause fatal ventricular arrhythmias in young individuals during ß-adrenergic stimulation. OBJECTIVE: This study sought to determine the effects of a novel RyR2-G230C mutation and whether this mutation and RyR2-P2328S alter the sensitivity of the channel to luminal calcium (Ca(2+)). METHODS AND RESULTS: Functional characterizations of recombinant human RyR2-G230C channels were performed under conditions mimicking stress. Human RyR2 mutant channels were generated by site-directed mutagenesis and heterologously expressed in HEK293 cells together with calstabin2. RyR2 channels were measured to examine the regulation of the channels by cytosolic versus luminal sarcoplasmic reticulum Ca(2+). A 50-year-old white man with repeated syncopal episodes after exercise had a cardiac arrest and harbored the mutation RyR2-G230C. cAMP-dependent protein kinase-phosphorylated RyR2-G230C channels exhibited a significantly higher open probability at diastolic Ca(2+) concentrations, associated with a depletion of calstabin2. The luminal Ca(2+) sensitivities of RyR2-G230C and RyR2-P2328S channels were WT-like. CONCLUSIONS: The RyR2-G230C mutant exhibits similar biophysical defects compared with previously characterized CPVT mutations: decreased binding of the stabilizing subunit calstabin2 and a leftward shift in the Ca(2+) dependence for activation under conditions that simulate exercise, consistent with a "leaky" channel. Both RyR2-G230C and RyR2-P2328S channels exhibit normal luminal Ca(2+) activation. Thus, diastolic sarcoplasmic reticulum Ca(2+) leak caused by reduced calstabin2 binding and a leftward shift in the Ca(2+) dependence for activation by diastolic levels of cytosolic Ca(2+) is a common mechanism underlying CPVT.

Role of chronic ryanodine receptor phosphorylation in heart failure and ß-adrenergic receptor blockade in mice.

Increased sarcoplasmic reticulum (SR) Ca2+ leak via the cardiac ryanodine receptor/calcium release channel (RyR2) is thought to play a role in heart failure (HF) progression. Inhibition of this leak is an emerging therapeutic strategy. To explore the role of chronic PKA phosphorylation of RyR2 in HF pathogenesis and treatment, we generated a knockin mouse with aspartic acid replacing serine 2808 (mice are referred to herein as RyR2-S2808D+/+ mice). This mutation mimics constitutive PKA hyperphosphorylation of RyR2, which causes depletion of the stabilizing subunit FKBP12.6 (also known as calstabin2), resulting in leaky RyR2. RyR2-S2808D+/+ mice developed age-dependent cardiomyopathy, elevated RyR2 oxidation and nitrosylation, reduced SR Ca2+ store content, and increased diastolic SR Ca2+ leak. After myocardial infarction, RyR2-S2808D+/+ mice exhibited increased mortality compared with WT littermates. Treatment with S107, a 1,4-benzothiazepine derivative that stabilizes RyR2-calstabin2 interactions, inhibited the RyR2-mediated diastolic SR Ca2+ leak and reduced HF progression in WT and RyR2-S2808D+/+ mice. In contrast, ß-adrenergic receptor blockers improved cardiac function in WT but not in RyR2-S2808D+/+ mice.Thus, chronic PKA hyperphosphorylation of RyR2 results in a diastolic leak that causes cardiac dysfunction. Reversing PKA hyperphosphorylation of RyR2 is an important mechanism underlying the therapeutic action of ß-blocker therapy in HF.

Remodeling of ryanodine receptor complex causes "leaky" channels: a molecular mechanism for decreased exercise capacity.

During exercise, defects in calcium (Ca2+) release have been proposed to impair muscle function. Here, we show that during exercise in mice and humans, the major Ca2+ release channel required for excitation-contraction coupling (ECC) in skeletal muscle, the ryanodine receptor (RyR1), is progressively PKA-hyperphosphorylated, S-nitrosylated, and depleted of the phosphodiesterase PDE4D3 and the RyR1 stabilizing subunit calstabin1 (FKBP12), resulting in "leaky" channels that cause decreased exercise tolerance in mice. Mice with skeletal muscle-specific calstabin1 deletion or PDE4D deficiency exhibited significantly impaired exercise capacity. A small molecule (S107) that prevents depletion of calstabin1 from the RyR1 complex improved force generation and exercise capacity, reduced Ca2+-dependent neutral protease calpain activity and plasma creatine kinase levels. Taken together, these data suggest a possible mechanism by which Ca2+ leak via calstabin1-depleted RyR1 channels leads to defective Ca2+ signaling, muscle damage, and impaired exercise capacity.

A function for tyrosine phosphorylation of type 1 inositol 1,4,5-trisphosphate receptor in lymphocyte activation.

Sustained elevation of intracellular calcium by Ca2+ release-activated Ca2+ channels is required for lymphocyte activation. Sustained Ca2+ entry requires endoplasmic reticulum (ER) Ca2+ depletion and prolonged activation of inositol 1,4,5-trisphosphate receptor (IP(3)R)/Ca2+ release channels. However, a major isoform in lymphocyte ER, IP3R1, is inhibited by elevated levels of cytosolic Ca2+, and the mechanism that enables the prolonged activation of IP(3)R1 required for lymphocyte activation is unclear. We show that IP(3)R1 binds to the scaffolding protein linker of activated T cells and colocalizes with the T cell receptor during activation, resulting in persistent phosphorylation of IP(3)R1 at Tyr353. This phosphorylation increases the sensitivity of the channel to activation by IP(3) and renders the channel less sensitive to Ca2+ -induced inactivation. Expression of a mutant IP3R1-Y353F channel in lymphocytes causes defective Ca2+ signaling and decreased nuclear factor of activated T cells activation. Thus, tyrosine phosphorylation of IP3R1-Y353 may have an important function in maintaining elevated cytosolic Ca2+ levels during lymphocyte activation.

A mechanism for sudden infant death syndrome (SIDS): stress-induced leak via ryanodine receptors.

BACKGROUND: Sudden infant death syndrome (SIDS) is the leading cause of postneonatal mortality in the United States. Mutations in the RyR2-encoded cardiac ryanodine receptor cause the highly lethal catecholaminergic polymorphic ventricular tachycardia (CPVT1) in the young. OBJECTIVE: The purpose of this study was to determine the spectrum and prevalence of RyR2 mutations in a large cohort of SIDS cases. METHODS: Using polymerase chain reaction, denaturing high performance liquid chromatography, and direct DNA sequencing, a targeted mutational analysis of RyR2 was performed on genomic DNA isolated from frozen necropsy tissue on 134 unrelated cases of SIDS (57 females, 77 males; 83 white, 50 black, 1 Hispanic; average age = 2.7 months). RyR2 mutations were engineered by site-directed mutagenesis, heterologously expressed in HEK293 cells, and functionally characterized using single-channel recordings in planar lipid bilayers. RESULTS: Overall, two distinct and novel RyR2 mutations were identified in two cases of SIDS. A 6-month-old black female hosted an R2267H missense mutation, and a 4-week-old white female infant harbored a S4565R mutation. Both nonconservative amino acid substitutions were absent in 400 reference alleles, involved conserved residues, and were localized to key functionally significant domains. Under conditions that simulate stress [Protein Kinase A (PKA) phosphorylation] during diastole (low activating [Ca2+]), SIDS-associated RyR2 mutant channels displayed a significant gain-of-function phenotype consistent with the functional effect of previously characterized CPVT-associated RyR2 mutations. CONCLUSIONS: Here we report a novel pathogenic mechanism for SIDS, whereby SIDS-linked RyR2 mutations alter the response of the channels to sympathetic nervous system stimulation such that during stress the channels become "leaky" and thus potentially trigger fatal cardiac arrhythmias.

Enrichment of endoplasmic reticulum with cholesterol inhibits sarcoplasmic-endoplasmic reticulum calcium ATPase-2b activity in parallel with increased order of membrane lipids: implications for depletion of endoplasmic reticulum calcium stores and apoptosis in cholesterol-loaded macrophages.

Macrophages in advanced atherosclerotic lesions accumulate large amounts of unesterified, or "free," cholesterol (FC). FC accumulation induces macrophage apoptosis, which likely contributes to plaque destabilization. Apoptosis is triggered by the enrichment of the endoplasmic reticulum (ER) with FC, resulting in depletion of ER calcium stores, and induction of the unfolded protein response. To explain the mechanism of ER calcium depletion, we hypothesized that FC enrichment of the normally cholesterol-poor ER membrane inhibits the macrophage ER calcium pump, sarcoplasmic-endoplasmic reticulum calcium ATPase-2b (SERCA2b). FC enrichment of ER membranes to a level similar to that occurring in vivo inhibited both the ATPase activity and calcium sequestration function of SERCA2b. Enrichment of ER with ent-cholesterol or 14:0-18:0 phosphatidylcholine, which possess the membrane-ordering properties of cholesterol, also inhibited SERCA2b. Moreover, at various levels of FC enrichment of ER membranes, there was a very close correlation between increasing membrane lipid order, as monitored by 16-doxyl-phosphatidycholine electron spin resonance, and SERCA2b inhibition. In view of these data, we speculate that SERCA2b, a conformationally active protein with 11 membrane-spanning regions, loses function due to decreased conformational freedom in FC-ordered membranes. This biophysical model may underlie the critical connection between excess cholesterol, unfolded protein response induction, macrophage death, and plaque destabilization in advanced atherosclerosis.