Role of mitochondria in the myopathy of juvenile dermatomyositis and implications for skeletal muscle calcinosis

OBJECTIVES

To elucidate mechanisms contributing to skeletal muscle calcinosis in patients with juvenile dermatomyositis.

METHODS

A well-characterized cohorts of JDM (n = 68), disease controls (polymyositis, n = 7; juvenile SLE, n = 10, and RNP + overlap syndrome, n = 12), and age-matched health controls (n = 17) were analyzed for circulating levels of mitochondrial (mt) markers including mtDNA, mt-nd6, and anti-mitochondrial antibodies (AMAs) using standard qPCR, ELISA, and novel-in-house assays, respectively. Mitochondrial calcification of affected tissue biopsies was confirmed using electron microscopy and energy dispersive X-ray analysis. A human skeletal muscle cell line, RH30, was used to generate an in vitro calcification model. Intracellular calcification is measured by flow cytometry and microscopy. Mitochondria were assessed for mtROS production and membrane potential by flow cytometry and real-time oxygen consumption rate by Seahorse bioanalyzer. Inflammation (interferon-stimulated genes) was measured by qPCR.

RESULTS

In the current study, patients with JDM exhibited elevated levels of mitochondrial markers associated with muscle damage and calcinosis. Of particular interest are AMAs predictive of calcinosis. Human skeletal muscle cells undergo time- and dose-dependent accumulation of calcium phosphate salts with preferential localization to mitochondria. Calcification renders skeletal muscle cells mitochondria stressed, dysfunctional, destabilized, and interferogenic. Further, we report that inflammation induced by interferon-alpha amplifies mitochondrial calcification of human skeletal muscle cells via the generation of mitochondrial reactive oxygen species (mtROS).

CONCLUSIONS

Overall, our study demonstrates the mitochondrial involvement in the skeletal muscle pathology and calcinosis of JDM and mtROS as a central player in the calcification of human skeletal muscle cells. Therapeutic targeting of mtROS and/or upstream inducers, such as inflammation, may alleviate mitochondrial dysfunction, leading to calcinosis. AMAs can potentially identify patients with JDM at risk for developing calcinosis.

Calcinosis in dermatomyositis: Origins and possible therapeutic avenues

Calcinosis, insoluble calcium compounds deposited in skin and other tissues, is a crippling sequela of dermatomyositis. Prolonged disease associated with ongoing inflammation, ischemia, repetitive trauma, and certain autoantibodies are associated with calcinosis. Herein, we describe potential pathogenic mechanisms including the role of mitochondrial calcification. There are no widely effective treatments for calcinosis. We review available pharmacologic therapies for calcinosis including those targeting calcium and phosphorus metabolism; immunosuppressive/anti-inflammatory therapies; and vasodilators. Mounting evidence supports the use of various formulations of sodium thiosulfate in the treatment of calcinosis. Although the early institution of aggressive immunosuppression may prevent calcinosis in juvenile dermatomyositis, only limited data support improvement once it has developed. Minocycline can be useful particularly for lesions associated with surrounding inflammation. Powerful vasodilators, such as prostacyclin analogs, may have promise in the treatment of calcinosis, but further studies are necessary. Surgical removal of lesions when amenable is our treatment of choice.

Subcutaneous calcinosis: Is it different between systemic sclerosis and dermatomyositis?

Calcinosis cutis is the deposition of insoluble calcium in the skin and subcutaneous tissues. It is a manifestation of several autoimmune connective tissue diseases, most frequently with systemic sclerosis and juvenile dermatomyositis, followed by adult dermatomyositis. Autoimmune connective tissue disease-associated calcinosis is of the dystrophic subtype, which occurs at sites of damaged tissue in the setting of normal serum calcium and phosphate levels. In juvenile dermatomyositis, calcinosis is considered a marker of ongoing disease activity and possibly inadequate treatment, while in adult dermatomyositis, it is a hallmark of skin damage due to chronic rather than active disease. Calcinosis is associated with long disease duration in systemic sclerosis and dermatomyositis, anti-polymyositis/sclerosis autoantibodies in systemic sclerosis and NXP-2 and melanoma differentiation-associated gene 5 in dermatomyositis. Calcinosis in systemic sclerosis occurs most frequently in the hands, particularly the fingers, whereas in dermatomyositis, it affects mainly the trunk and extremities. The primary mineral component of calcinosis is hydroxyapatite in systemic sclerosis and carbonate apatite in dermatomyositis. Calcinosis in dermatomyositis and systemic sclerosis share some pathogenic mechanisms, but vascular hypoxia seems to play a more important role in systemic sclerosis, whereas the release of calcium from mitochondria in muscle cells damaged by myopathy may be a primary mechanism contributing to dermatomyositis-related calcinosis. Multiple treatment strategies for dermatomyositis and systemic sclerosis-related calcinosis have been used with variable results. Early aggressive treatment of underlying myositis in patients with dermatomyositis may improve long-term outcomes of calcinosis. A better understanding of the pathogenesis of calcinosis is needed to improve treatment options.

Morphological Characteristics of Idiopathic Inflammatory Myopathies in Juvenile Patients

Background: In juvenile idiopathic inflammatory myopathies (IIMs), morphological characteristic features of distinct subgroups are not well defined. New treatment strategies require a precise diagnosis of the subgroups in IIM, and, therefore, knowledge about the pathomorphology of juvenile IIMs is warranted. Methods: Muscle biopsies from 15 patients (median age 8 (range 3–17) years, 73% female) with IIM and seven controls were analyzed by standard methods, immunohistochemistry, and transmission electron microscopy (TEM). Detailed clinical and laboratory data were accessed retrospectively. Results: Proximal muscle weakness and skin symptoms were the main clinical symptoms. Dermatomyositis (DM) was diagnosed in 9/15, antisynthetase syndrome (ASyS) in 4/15, and overlap myositis (OM) in 2/15. Analysis of skeletal muscle tissues showed inflammatory cells and diffuse upregulation of MHC class I in all subtypes. Morphological key findings were COX-deficient fibers as a striking pathology in DM and perimysial alkaline phosphatase positivity in anti-Jo-1-ASyS. Vascular staining of the type 1 IFN-surrogate marker, MxA, correlated with endothelial tubuloreticular inclusions in both groups. None of these specific morphological findings were present in anti-PL7-ASyS or OM patients. Conclusions: Morphological characteristics discriminate IIM subtypes in juvenile patients, emphasizing differences in aetiopathogenesis and supporting the notion of individual and targeted therapeutic strategies.

Inflammatory myopathies in childhood

Myositis in childhood can occur under different conditions and with various aetiologies, juvenile dermatomyositis (jDM) being by far the most frequent entity. The exact diagnostic workup and precise assessment of muscular as well as extramuscular involvement of organs in these systemic autoimmune diseases are relevant for specific and adjunct treatment of complications. Many new insights have become available with respect to the pathophysiological concepts as well as modern diagnostic measures and therapeutic approaches. Autoantibody detection in the serum of children with myositis is one of the major novelties that has become widely used and that is indeed helpful for diagnostic and prognostic measures. The pathophysiological relevance of type I interferons in jDM has been studied intensively in the past years. jDM is now seen as an acquired interferonopathy and first therapeutic consequences have been drawn from this pathogenic finding with the use of Janus-kinase inhibitors for severe and not otherwise treatable children.

Serum level of fetuin-A in systemic lupus erythematosus patients: association with atherosclerosis and disease activity

OBJECTIVES

We aimed in this study to determine the level of serum fetuin-A level in systemic lupus erythematosus patients, assess the correlation between serum fetuin-A level and the activity of disease and the frequency of musculoskeletal manifestations, and detect the frequency of atherosclerosis among these patients by using carotid ultrasonography.

METHODS

This case-control study was carried out on 31 SLE patients attending the inpatient and outpatient clinics of Rheumatology and Rehabilitation Department, Faculty of Medicine, Zagazig university hospitals and 31 apparently healthy age- and sex-matched controls between January 1,2017, and December 31, 2018.

RESULTS

There is a highly significant difference between the two studied groups as regard fetuin-A and carotid intima-media thickness. There is a strong positive significant correlation between fetuin-A with C3 and a negative significant correlation between fetuin-A with Anti-dsDNA, SLEDAI, and carotid intima-media thickness in case group.

CONCLUSION

Fetuin-A levels were decreased in SLE patients, and these levels were inversely correlated with carotid intima-media thickness. Key Points • Fetuin-A level is a biomarker of atherosclerosis and asses disease activity in SLE patients.

Calcinosis Biomarkers in Adult and Juvenile Dermatomyositis

Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by muscle weakness and cutaneous manifestations in adults and children. Calcinosis, a complication of DM, is the abnormal deposition of insoluble calcium salts in tissues, including skin, subcutaneous tissue, tendons, fascia, and muscle. Calcinosis is more commonly seen in juvenile DM (JDM), but also develops in adult DM. Although the mechanism of calcinosis remains unclear, several pathogenic hypotheses have been proposed, including intracellular accumulation of calcium secondary to an alteration of the cellular membrane by trauma and inflammation, local vascular ischemia, dysregulation of mechanisms controlling the deposition and solubility of calcium and phosphate, and mitochondrial damage of muscle cells. Identifying calcinosis biomarkers is important for early disease detection and risk assessment, and may lead to novel therapeutic targets for the prevention and treatment of DM-associated calcinosis. In this review, we summarize myositis autoantibodies associated with calcinosis in DM, histopathology and chemical composition of calcinosis, genetic and inflammatory markers that have been studied in adult DM and JDM-associated calcinosis, as well as potential novel biomarkers.

Fetuin-A and Fetuin-B in Non-Alcoholic Fatty Liver Disease: A Meta-Analysis and Meta-Regression

The magnitude of the effect of fetuin-A and fetuin-B on non-alcoholic fatty liver disease (NAFLD) remains undefined. Therefore, the aim of this study was to synthesize previous findings to obtain a reliable estimation of this relationship. This study was registered in PROSPERO with the number CRD42019126314. Studies published not later than March 2019, examining the relationship between fetuin-A, fetuin-B, and NAFLD, were identified by a systematic search in the electronic databases of the Web of Science, PubMed, Embase, and Cochrane Library. Pooled estimates of standardized mean difference (SMD), calculated using the random-effects model in a meta-analysis, were applied to estimate the strength of the association between fetuin-A, fetuin-B, and NAFLD. Thirty publications were identified and analyzed based on specified inclusion criteria. Collectively, they consisted of 3800 NAFLD participants and 3614 controls. Compared with the controls, significant higher values of the fetuin-A (SMD = 0.83, 95% CI: 0.59 to 1.07, Z = 6.82, p < 0.001) and fetuin-B (SMD = 0.18, 95% CI: 0.02 to 0.33, Z = 2.27, p = 0.023) were observed in NAFLD patients. Meanwhile, in the subgroup analysis, the effect value of fetuin-A in the NASH group was significantly higher than that in the NAFL group (p = 0.036). The findings of this study suggest that elevated fetuin-A and fetuin-B may independently indicate the occurrence of NAFLD. Nevertheless, further research is needed to confirm these results.

Fetuin-A in Metabolic syndrome: A systematic review and meta-analysis

Objective

Fetuin-A has been associated with the progression of metabolic syndrome, but previous studies found inconsistent results on the relationship between metabolic syndrome and the concentration of fetuin-A. The aim of this study was to perform a meta-analysis to summarize previous findings on this relationship.

Method

This study was registered with the International Prospective Register of Systematic Reviews PROSPERO (CRD42019129566). Studies examining the relationship between metabolic syndrome and the concentration of circulating fetuin-A were identified using a systematic search in the electronic databases of Embase, PubMed, Web of Science, and Cochrane Library before March 2019. A random effects model was used to summarize the effect size of the association in terms of the standardized mean difference (SMD).

Results

Fourteen eligible studies compared fetuin-A concentrations between 4,551 metabolic syndrome patients and 8,805 controls. The circulating fetuin-A concentration was significantly higher in the metabolic syndrome patients than in the controls (SMD = 0.65, 95% confidence interval (CI): 0.48 to 0.83, Z = 7.18, p<0.001). Besides, circulating fetuin-A was a risk factor for metabolic syndrome (odds ratio 1.23, 95% CI: 1.08 to 1.40).

Conclusion

These findings suggest that fetuin-A may be an important indicator for metabolic syndrome, in which case this may lead to new perspectives in early diagnosis, identification of novel biomarkers, and providing novel targets for pharmacological interventions.

Can Fetuin-A, CRP, and WBC Levels Be Predictive Values in the Diagnosis of Acute Appendicitis in Children with Abdominal Pain?

Background: Acute appendicitis (AA) is the most common cause of emergency surgery. Therefore, perforation is common. Early diagnosis and new markers are needed. The aim of this study was to investigate the effects of plasma Fetuin-A (FA) levels in patients with an acute abdomen (AB). Material and Method: This prospective study included 107 patients younger than 16 years of age who were admitted to the emergency department for abdominal pain between January and December 2018. The patients who presented abdominal pain were divided into two groups as AA and other causes (OC) of AB. Patients with acute appendicitis; intraperitoneal, retrocolic/retrocecal, and appendicitis were divided into three groups. Additionally, the AA group was divided into two groups as perforated appendicitis and non-perforated appendicitis. Serum FA levels of the patients were evaluated in the emergency department. Results: In the AA group, C-reactive protein (CRP) and white blood cell (WBC) levels were higher, and FA levels were significantly lower than in the AB group. Intraperitoneal localization was 95.2% and perforation was frequent. When significant values in the univariate regression analysis for acute abdomen and perforation were compared in the multivariate regression analysis, CRP, WBC, and FA levels were found to be prognostic. Furthermore, decreased FA levels were associated with AA, while too greatly decreased FA levels were associated with the risk of perforation. Conclusion: Current diagnosis can be made by history, physical examination, laboratory, and imaging methods in appendicitis cases. While trying to diagnose AA in children, the FA, CRP, and WBC levels may be predictive values to identify risk factors.

Evaluation of Serum Fetuin-A and Osteoprotegerin Levels in Patients with Psoriasis

Psoriasis patients are determined to have a high ratio of coronary artery calcification. Fetuin-A and osteoprotegerin are systemic calcification inhibitors and related to vascular calcification and cardiovascular mortality. In this study we investigated the relationship between fetuin-A and osteoprotegerin levels in psoriasis patients. The study included 40 healthy volunteers and 40 psoriasis patients. Venous blood were collected from healthy volunteers and psoriasis patients in order to search the fetuin-A and osteoprotegerin levels. Disease severity were grouped as mild, moderate and severe according to psoriasis area and severity index (PASI). The relationship between fetuin-A and osteoprotegerin levels and clinical features as sex, PASI and presence of psoriatic arthritis were analyzed. Fetuin-A levels in psoriasis patients were statistically lower than the control group (p < 0.001). In serum osteoprotegerin levels, no statistically significant difference was found in two groups (p > 0.05). Serum fetuin-A and osteoprotegerin level differences were not statistically significant between patients with psoriatic arthritis history and those without. When we grouped patients in respect of their sexes fetuin-A and osteoprotegerin levels of males and females were not significantly different (p > 0.05). No correlation was detected between the ages and PASI scores and the fetuin-A and osteoprotegerin levels of patients. As a result fetuin-A levels in psoriasis patients are found to be low but not related to disease severity. In the light of our results we concluded that fetuin-A may have a role in psoriasis pathogenesis and may contribute to the calcification process developed in psoriasis.

Vascular Calcification in Uremia: New-Age Concepts about an Old-Age Problem

A hallmark of aging, and major contributor to the increased prevalence of cardiovascular disease in patients with chronic kidney disease (CKD), is the progressive structural and functional deterioration of the arteries and concomitant accrual of mineral. Vascular calcification (VC) was long viewed as a degenerative age-related pathology that resulted from the passive deposition of mineral in the extracellular matrix; however, since the discovery of "bone-related" protein expression in calcified atherosclerotic plaques over 20 years ago, a plethora of studies have evoked the now widely accepted view that VC is a highly regulated and principally cell-mediated phenomenon that recapitulates many features of physiologic ossification. Central to this theory are changes in vascular smooth muscle cell (VSMC) phenotype and viability, thought to be driven by chronic exposure to a number of dystrophic stimuli characteristics of the uremic state. Here, dedifferentiated synthetic VSMCs are seen to spawn calcifying matrix vesicles that actively seed mineralization of the arterial matrix. This review provides an overview of the major epidemiological, histological, and molecular aspects of VC in the context of CKD, and a counterpoint to the prevailing paradigm that emphasizes the primacy of VSMC-mediated mechanisms. Particular focus is given to the import of protein and small molecule inhibitors in regulating physiologic and pathological mineralization and the emerging role of mineral nanoparticles and their interplay with proinflammatory processes.

The presentation, assessment, pathogenesis, and treatment of calcinosis in juvenile dermatomyositis

Calcinosis is one of the hallmark sequelae of juvenile dermatomyositis (JDM), and despite recent progress in the therapy of JDM, dystrophic calcification still occurs in approximately one third of patients. This review discusses our current, albeit limited, understanding of risk factors for the development of calcinosis in JDM, as well as approaches to assessment, and current views on its pathogenesis. Anecdotal approaches to treating calcinosis associated with JDM, including both anti-inflammatory therapies and agents aimed at inhibiting the deposition of calcium hydroxyapatite, are reviewed. An improved understanding of the pathogenesis of calcinosis, the establishment of standardized measurement tools to assess calcinosis, and randomized controlled trials employing more sensitive outcome measures are needed to develop efficacious therapies for this often disabling complication.

Calcinosis in juvenile dermatomyositis is influenced by both anti-NXP2 autoantibody status and age at disease onset

OBJECTIVE

Calcinosis is a major cause of morbidity in JDM and has previously been linked to anti-NXP2 autoantibodies, younger age at disease onset and more persistent disease activity. This study aimed to investigate the clinical associations of anti-NXP2 autoantibodies in patients with JDM stratified by age at disease onset.

METHODS

A total of 285 patients with samples and clinical data were recruited via the UK Juvenile Dermatomyositis Cohort and Biomarker Study. The presence of anti-NXP2 was determined by both immunoprecipitation and ELISA. Logistic regression analysis was performed to assess the age-dependent relationship between anti-NXP2 and the development of calcinosis and disease activity measures.

RESULTS

We identified anti-NXP2 autoantibodies in 56 patients (20%). While in all patients younger age at disease onset was associated with an increased risk of calcinosis and this relationship was nearly linear, anti-NXP2 autoantibodies substantially increased the risk of calcinosis across all ages (P = 0.025) and were detectable prior to calcinosis development. Children with anti-NXP2 autoantibodies had a greater degree of weakness (median lowest ever Childhood Myositis Assessment Score 29.6 vs 42) and were less likely to be in remission at 2 years post-diagnosis. No difference in disease activity was seen 4 years post-diagnosis.

CONCLUSION

Children diagnosed at a young age have a high risk of calcinosis regardless of autoantibody status. However, the presence of anti-NXP2 autoantibodies substantially increases the risk of calcinosis across all ages and is associated with disease severity.

IL-6-accelerated calcification by induction of ROR2 in human adipose tissue-derived mesenchymal stem cells is STAT3 dependent

OBJECTIVE

The mechanisms of ectopic calcification in inflammatory diseases are poorly understood. We investigated the effects of inflammatory cytokines on the mechanisms of calcification in human adipose tissue-derived mesenchymal stem cells (hADSCs).

METHODS

The effects of inflammatory cytokines were evaluated using hADSCs cultured in osteoblast induction medium. mRNA expression was measured by real-time PCR and protein levels were measured by western blotting. Cell mineralization was evaluated by Alizarin Red S staining.

RESULTS

In hADSCs, administration of IL-6/soluble IL-6 receptor (sIL-6R), TNF or IL-1β accelerated calcification through enhanced expression of an osteoblast differentiation marker, runt-related transcription factor 2 (RUNX2). IL-6/sIL-6R had the greatest effect. The transcription of mRNA for receptor tyrosine kinase-like orphan receptor 2 (ROR2), involved in the non-canonical wingless-type (WNT) MMTV integration site pathway, was increased, while β-catenin expression, an essential factor in the canonical WNT signalling pathway for osteoblast differentiation, did not change. Suppression of signal transducer and activator of transcription 3 (STAT3), but not STAT1, by small interfering RNA (siRNA) exerted a strong inhibitory effect on RUNX2 and ROR2 expression, and inhibited accelerated calcification.

CONCLUSION

IL-6/sIL-6R stimulation accelerated the ROR2/WNT5A pathway in hADSCs in a STAT3-dependent manner, resulting in augmented calcification. These results suggest that the mechanisms of ectopic calcification accelerated by IL-6 in hADSCs may be involved in chronic inflammatory tissues and that IL-6 inhibitors may be beneficial in the treatment of ectopic calcification in inflammatory diseases.

Plasma levels of osteopontin identify patients at risk for organ damage in systemic lupus erythematosus

Introduction

Osteopontin (OPN) has been implicated as a mediator of Th17 regulation via type I interferon (IFN) receptor signaling and in macrophage activity at sites of tissue repair. This study assessed whether increased circulating plasma OPN (cOPN) precedes development of organ damage in pediatric systemic lupus erythematosus (pSLE) and compared it to circulating plasma neutrophil gelatinase-associated lipocalin (cNGAL), a predictor of increased SLE disease activity.

Methods

cOPN and cNGAL were measured in prospectively followed pSLE (n = 42) and adult SLE (aSLE; n = 23) patients and age-matched controls. Time-adjusted cumulative disease activity and disease damage were respectively assessed using adjusted-mean SLE disease activity index (SLEDAI) (AMS) and SLICC/ACR damage index (SDI).

Results

Compared to controls, elevated cOPN and cNGAL were observed in pSLE and aSLE. cNGAL preceded worsening SLEDAI by 3-6 months (P = 0.04), but was not associated with increased 6-month AMS. High baseline cOPN, which was associated with high IFNalpha activity and expression of autoantibodies to nucleic acids, positively correlated with 6-month AMS (r = 0.51 and 0.52, P = 0.001 and 0.01 in pSLE and aSLE, respectively) and was associated with SDI increase at 12 months in pSLE (P = 0.001). Risk factors for change in SDI in pSLE were cOPN (OR 7.5, 95% CI [2.9-20], P = 0.03), but not cNGAL, cumulative prednisone, disease duration, immunosuppression use, gender or ancestry using univariate and multivariate logistic regression. The area under the curve (AUC) when generating the receiver-operating characteristic (ROC) of baseline cOPN sensitivity and specificity for the indication of SLE patients with an increase of SDI over a 12 month period is 0.543 (95% CI 0.347-0.738; positive predictive value 95% and negative predictive value 38%).

Conclusion

High circulating OPN levels preceded increased cumulative disease activity and organ damage in SLE patients, especially in pSLE, and its value as a predictor of poor outcome should be further validated in large longitudinal cohorts.

Comparison of children with onset of juvenile dermatomyositis symptoms before or after their fifth birthday in a UK and Ireland juvenile dermatomyositis cohort study

Objective

To compare 2 groups of children with juvenile dermatomyositis (DM), those with onset of symptoms before their fifth birthday versus those whose disease begins either on or after their fifth birthday, and to assess whether age at onset is associated with differences in disease presentation, treatments received, or outcomes 2 years after diagnosis.

Methods

Data were analyzed on children recruited to a UK juvenile DM cohort study with a diagnosis of probable or definite juvenile DM and less than 12 months between diagnosis and recruitment.

Results

Fifty-five (35%) of 157 children had onset of symptoms before their fifth birthday. At diagnosis, cutaneous ulceration was found in 32.7% of the younger group versus 11.8% of the older group (P = 0.003). Facial or body swelling was reported more often in the younger group, whereas headaches, alopecia, and Raynaud's phenomenon were all more frequently reported in the older group. At followup 2 years later, there were no important differences in outcomes between the groups. More than 90% of patients in both groups received both methotrexate and steroids. Twenty-three percent of both groups remained on steroids 2 years after diagnosis.

Conclusion

Our study showed that children with juvenile DM with disease onset at age <5 years are more likely to present with ulcerative skin disease and edema. There were no clinically significant differences in outcomes between the 2 groups.

The Immunohistochemical Patterns of Calcification-related Molecules in the Epidermis and Dermis of the Zebrafish (Danio rerio)

BACKGROUND

The scales of bony fish represent a significant reservoir of calcium and calcification of the elasmoid scale is known to be associated with deposition of mineral crystals from the epidermis to dermis. However, little is known about the exact mechanisms of calcium deposition, mobilization and regeneration occurring in the zebrafish skin.

OBJECTIVE

The purpose of this study was to investigate the expression of calcification-related molecular mediators in both the epidermis and dermis of the zebrafish (Danio rerio), using immunohistochemical study.

METHODS

We examined the skin of zebrafish in four populations of different ages (i.e. 20 days post-fertilization (dpf), 35 dpf, 50 dpf, and the adult zebrafish), using several immunohistochemical markers, including bone morphogenetic protein 4 (BMP-4), β-catenin, osteocalcin, osteopontin and osteonectin.

RESULTS

BMP-4, osteopontin and osteonectin were moderately expressed in the epidermis of zebrafish after 35 dpf. Also, some of the cells in the upper dermis showed strong positivity for BMP-4, osteocalcin, osteopontin and osteonetin.

CONCLUSION

Our results suggest that BMP-4, osteocalcin, osteopontin and osteonectin may play a role in the process of calcification of the elasmoid scale.

SPP1 genotype is a determinant of disease severity in Duchenne muscular dystrophy

OBJECTIVE

Duchenne muscular dystrophy (DMD) is the most common single-gene lethal disorder. Substantial patient-patient variability in disease onset and progression and response to glucocorticoids is seen, suggesting genetic or environmental modifiers.

METHODS

Two DMD cohorts were used as test and validation groups to define genetic modifiers: a Padova longitudinal cohort (n = 106) and the Cooperative International Neuromuscular Research Group (CINRG) cross-sectional natural history cohort (n = 156). Single nucleotide polymorphisms to be genotyped were selected from mRNA profiling in patients with severe vs mild DMD, and genome-wide association studies in metabolism and polymorphisms influencing muscle phenotypes in normal volunteers were studied.

RESULTS

Effects on both disease progression and response to glucocorticoids were observed with polymorphism rs28357094 in the gene promoter of SPP1 (osteopontin). The G allele (dominant model; 35% of subjects) was associated with more rapid progression (Padova cohort log rank p = 0.003), and 12%-19% less grip strength (CINRG cohort p = 0.0003).

CONCLUSIONS

Osteopontin genotype is a genetic modifier of disease severity in Duchenne dystrophy. Inclusion of genotype data as a covariate or in inclusion criteria in DMD clinical trials would reduce intersubject variance, and increase sensitivity of the trials, particularly in older subjects.

A national registry for juvenile dermatomyositis and other paediatric idiopathic inflammatory myopathies: 10 years' experience; the Juvenile Dermatomyositis National (UK and Ireland) Cohort Biomarker Study and Repository for Idiopathic Inflammatory Myopathies

OBJECTIVES

The paediatric idiopathic inflammatory myopathies (IIMs) are a group of rare chronic inflammatory disorders of childhood, affecting muscle, skin and other organs. There is a severe lack of evidence base for current treatment protocols in juvenile myositis. The rarity of these conditions means that multicentre collaboration is vital to facilitate studies of pathogenesis, treatment and disease outcomes. We have established a national registry and repository for childhood IIM, which aims to improve knowledge, facilitate research and clinical trials, and ultimately to improve outcomes for these patients.

METHODS

A UK-wide network of centres and research group was established to contribute to the study. Standardized patient assessment, data collection forms and sample protocols were agreed. The Biobank includes collection of peripheral blood mononuclear cells, serum, genomic DNA and biopsy material. An independent steering committee was established to oversee the use of data/samples. Centre training was provided for patient assessment, data collection and entry.

RESULTS

Ten years after inception, the study has recruited 285 children, of which 258 have JDM or juvenile PM; 86% of the cases have contributed the biological samples. Serial sampling linked directly to the clinical database makes this a highly valuable resource. The study has been a platform for 20 sub-studies and attracted considerable funding support. Assessment of children with myositis in contributing centres has changed through participation in this study.

CONCLUSIONS

This establishment of a multicentre registry and Biobank has facilitated research and contributed to progress in the management of a complex group of rare muscloskeletal conditions.

Calcific panniculitis in adult-onset dermatomyositis

Dermatomyositis (DM) is an idiopathic inflammatory myopathy associated with characteristic cutaneous features. Panniculitis is a rarely reported clinical finding in this condition. This report describes two cases of adult-onset DM complicated by severe calcific panniculitis. In both cases, the associated pain and loss of function seemed to be best managed on combination anti-malarial therapy with mepacrine and hydroxychloroquine.

The physiologic development of fetuin-a serum concentrations in children

Fetuin-A prevents tissue calcification by forming soluble complexes with calcium and phosphate. A pathological depletion of serum fetuin-A has been observed in children on dialysis or after renal transplantation but knowledge on physiologic age-related changes in serum fetuin-A is limited. We prospectively evaluated serum fetuin-A in 133 infants and children, ranging from very low birth weight infants to adolescents. Highest serum fetuin-A levels were present between 23 and 30 wk of gestation (1 +/- 0.33 mg/mL). Thereafter, the values decreased. This decrease was linked to biological rather than chronological age. At 32 to 36 and 37 to 40 wk of gestation, the serum fetuin-A concentration was 0.63 +/- 0.26 and 0.63 +/- 0.21 mg/mL, respectively. Thereafter, the concentrations remained stable until adolescence at 0.58 +/- 0.12 mg/mL. Intercurrent infections were associated with a transient decrease of serum fetuin-A levels. The high serum fetuin-A concentrations in preterm children suggest that fetuin-A is of high physiologic impact for the fetal and the preterm-born organism, showing extensive tissue formation. This might point to a new mechanism contributing to organ damage in these patients, comparable with children on dialysis.

Fetuin-A serum concentrations in healthy children

Background

Serum fetuin-A has been shown to be a strong risk marker for myocardial infarction/stroke in the general population, and has been associated with vascular calcifications in patients with chronic kidney disease. Although these issues are worthy of being addressed in children and adolescents as well, adequate age- and gender-related reference values are missing.

Method

Within a healthy paediatric population ( n = 246), fetuin-A serum concentrations were determined (ELISA kit; Epitope Diagnostics, San Diego, CA, USA) essentially as described by the manufacturer. At the same time, serum protein and serum albumin were measured with established procedures (Beckman Coulter Inc., Krefeld, Germany). Subjects were stratified according to age (<1 yr [ n = 25], ≥1 and <6 yr [ n = 65], ≥6 and <12 yr [ n = 66], ≥12 yr and <16 [ n = 45] and ≥16 yr [ n = 45]), and both genders were equally distributed within each age cohort.

Results

Within each age cohort, fetuin-A serum concentrations were normally distributed, independent of age and gender and the respective reference range (mean ± 1.96 SD) is 0.22–0.70 g/L (0.46 ± 0.24 g/L).

Conclusion

Fetuin-A serum concentrations are independent of age and gender in a healthy paediatric population and are well comparable with those determined in adults with the same assay.

Juvenile dermatomyositis calcifications selectively displayed markers of bone formation

OBJECTIVE

To determine the presence of small integrin-binding ligand N-linked glycoprotein (SIBLING) and bone components in juvenile dermatomyositis (DM) pathologic calcifications.

METHODS

Calcifications were removed from 4 girls with juvenile DM symptoms for mean +/- SD 36.9 +/- 48.3 months and were stained for SIBLING proteins: full-length osteopontin (OPN), bone sialoprotein (BSP), dentin matrix protein 1 (DMP1), dentin phosphoprotein (DPP), and matrix extracellular phosphoglycoprotein (MEPE); bone markers: osteocalcin (OC), core-binding factor alpha 1 (CBFalpha1), and alkaline phosphatase (AP) for osteoblasts; tartrate-resistant acid phosphatase (TRAP) for osteoclasts; and the mineral regulators osteonectin (ON) and matrix Gla protein (MGP). The deposit center, periphery, adjacent connective tissue, and vascular endothelial cells were examined.

RESULTS

Alizarin red stained calcified deposits that did not localize with collagen, like bone, under polarized light. Hematoxylin and eosin stain revealed a paucity of connective tissue and absence of bone-like structures. The deposits, connective tissue, and vascular endothelial cells were positive for BSP, DPP, DMP1, and AP; MEPE was not detected. OC, ON, and MGP were present in the deposits and vascular endothelial cells; OPN and CBFalpha1 were present in deposits and connective tissue. TRAP-positive osteoclasts were localized to the calcification periphery.

CONCLUSION

The disorganized juvenile DM calcifications differ in structure, composition, and protein content from bone, suggesting that they may not form through an osteogenic pathway. Osteoclasts at the deposit surface represent an attempt to initiate its resolution.

[What's new in pediatric dermatology?]

The main selected articles in pediatric dermatology covered the following topics: development and maturation of the epidermal barrier in the neonate, iatrogenic events in the neonatal ICU, diagnostic value of minor birthmarks, complications, risk factors and treatment of hemangiomas, coagulopathy in venous malformations, epidemiology and dermoscopy of congenital and acquired melanocytic nevi in childhood, growth of the body surface area, new pathogenic concepts and treatment in atopic dermatitis, the impact of filaggrin deficiency, hereditary factors in Kawasaki disease, severe and drug resistant cases, management of juvenile dermatomyositis, treatment of childhood psoriasis with biologics, the new classification of epidermolysis bullosa and therapeutic approach with cell therapy, neurological impairment in xeroderma pigmentosum, behavioural anomalies in X-linked ichthyosis, guidelines for neurofibromatosis type I, the genetics of an hereditary hypotrichosis, infantile acne, rosacea in childhood, mast cell disease management and, last but not least, treatment of hair lice with silicone.