Muscle-associated Enzymes Research Articles

A systematic review and meta-analysis on the prevalence and clinical characteristics of dysphagia in patients with dermatomyositis.

Dermatomyositis (DM) is a rare autoimmune disease characterized by distinctive skin rash, muscle inflammation with symmetrical and progressive muscle weakness, and elevated serum levels of muscle-associated enzymes. DM may affect skeletal muscles involved in swallowing, leading to dysphagia, which can negatively impact individual's physical and psychosocial well-being. Despite this, dysphagia in patients with DM remains poorly understood. This systematic review and meta-analysis aimed to evaluate the prevalence and clinical features of dysphagia in patients with DM and juvenile DM (JDM). Four electronic databases were systematically searched until September 2022. Studies with patients with DM or JDM and dysphagia were included. The pooled prevalence of all included studies was calculated, and the clinical characteristics of dysphagia were qualitatively analyzed. Thirty-nine studies with 3335 patients were included. The overall pooled prevalence of dysphagia was 32.3% (95% CI: 0.270, 0.373) in patients with DM and 37.7% (95% CI: -0.031, 0.785) in patients with JDM. Subgroup analyses revealed that Sweden had the highest prevalence (66.7% [95% CI: 0.289, 1.044]), whereas Tunisia had the lowest prevalence (14.3% [95% CI: -0.040, 0.326]). Moreover, South America had the highest prevalence (47.0% [95% CI: 0.401, 0.538]), whereas Africa had the lowest prevalence (14.3% [95% CI: -0.040, 0.326]). Dysphagia in patients with DM and JDM was characterized by both oropharyngeal and esophageal dysfunctions, with predominant difficulties in motility. Our findings showed that dysphagia affects one in three patients with DM or JDM. However, the documentation on the diagnosis and management of dysphagia in the literature is inadequate. Our results highlighted the need to use both clinical and instrumental assessments to evaluate swallowing function in this population.

Circulating VEGF-A, TNF-α, CCL2, IL-6, and IFN-γ as biomarkers of cancer in cancer-associated anti-TIF1-γ antibody-positive dermatomyositis

ObjectivesThe objective of the current study was to detect plasma profiles of inflammatory cytokines for determining potential biomarkers indicating cancer presence among the anti-TIF1-γ antibody-positive dermatomyositis (DM) patients.MethodsTwenty-seven cancer-associated anti-TIF1-γ antibody-positive DM (Cancer TIF1-γ-DM) patients were compared with 20 anti-TIF1-γ antibody-positive DM patients without cancer (Non-cancer TIF1-γ-DM) and 10 healthy controls (HC). The plasma levels of 17 cytokines were determined using the Luminex 200 system. The ability of plasma VEGF-A, TNF-α, CCL2, IL-6, and IFN-γ levels to distinguish the presence of cancer was evaluated through the area under the curve (AUC) analysis. Potential protein interactions of TIF1-γ and the five cytokines were analyzed using the STRING database.ResultsVEGF-A, TNF-α, CCL2, IL-6, and IFN-γ plasma levels were significantly higher in the Cancer TIF1-γ-DM group, especially those without any anticancer treatment, than those in the non-cancer TIF1-γ-DM and HC groups. Meanwhile, anti-TIF1-γ antibody and the five cytokines could distinguish cancer presence in anti-TIF1-γ antibody-positive DM patients. The STRING network indicated that TIF1-γ potentially interacted with the cytokines. Positive correlations of VEGF-A among CCL2, IL-6, and IFN-γ and between IFN-γ and IL-6 were observed in Cancer TIF1-γ-DM patients. VEGF-A, TNF-α, CCL2, and IL-6 were positively associated with muscle-associated enzymes among the Cancer TIF1-γ-DM patients.ConclusionThe present study identified VEGF-A, TNF-α, CCL2, IL-6, and IFN-γ as significant potential biomarkers indicating the presence of cancer and demonstrated a more detailed cytokine profile during diagnosis. These biomarkers could provide better screening strategies and insight into the Cancer TIF1-γ-DM pathogenesis.Key Points• VEGF-A, TNF-α, CCL2, IL-6, and IFN-γ are potential biomarkers of cancer in cancer-associated anti-TIF1-γ antibody-positive dermatomyositis.Graphical abstractPotential pathogenic molecular mechanism of the cancer-associated anti-TIF1-γ antibody-positive dermatomyositis

Blood Reference Intervals for Antillean Manatees (Trichechus manatus manatus) from Puerto Rico.

Antillean manatees (Trichechus manatus manatus) are endangered throughout the southwestern Gulf of Mexico, the Caribbean coast of Central and South America, the Greater Antilles, and the northeastern coast of South America to Brazil. Establishing blood reference intervals is essential as a tool in classifying health status, diagnosing, establishing treatment regimens, and monitoring the progress of a disease in rescued manatees. We collected blood samples from 44 free-ranging and 26 rescued manatees from Puerto Rico between 1992 and 2020 for hematology and blood chemistry analysis. We obtained values for white blood cell count and red blood cell count, hemoglobin, hematocrit, platelet, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration, and red cell distribution width. A manual leukocyte differential allowed for the evaluation of different cell types. In addition, we performed a comprehensive metabolic panel on serum samples. These analytes were grouped based on six physiologic processes: liver-associated enzymes and pigments; muscle-associated enzymes; kidney-associated compounds and products; sugars, lipids, and pancreatic-associated enzymes; proteins; and electrolytes. For every parameter, summary statistics of values were calculated on all the samples. Reference ranges were determined as ±1 standard deviation around the mean. An unpaired two-sample T-test was done comparing males versus females and adults versus calves for any significant differences (p ≤ 0.05). We establish the reference intervals of hematology and blood chemistry for the population of Antillean manatees in Puerto Rico and compare them with those established for manatees from Belize, Brazil, Florida, Guyana, and Mexico.

Type II muscle fibers atrophy associated with silent corticotroph adenoma in a dog.

The Silent Corticotroph Adenoma (SCA) is a pituitary adenoma variant characterized by the immunoreactivity for adrenocorticotropic hormone (ACTH) and related peptides, without the clinical signs of Cushing's disease. SCA has been postulated to either secrete structurally abnormal ACTH that is inactive but detectable by immunohistochemistry or radioimmunoassay, or to secrete ACTH intermittently or at low levels continuously. Excess of ACTH has been associated to type II muscle atrophy. We describe a case of type II muscle fibers atrophy associated with silent corticotroph adenoma in a dog. The dog showed moderate to severe proximal muscle wasting and weakness with normal levels of muscle-associated enzymes. In the limb muscle biopsies, type II fibers were uniformly smaller than type I fibers. In temporalis muscles, there were few atrophic fibers, and several irregular areas of loss of enzymatic activity observed in NADH, SDH and COX stains. The tumour showed a trabecular growth pattern and immunohistochemical analysis demonstrated the presence of cytoplasmic immunoreactivity for ACTH. The muscle atrophy was considered to be related to an excess of inactive ACTH. Studying spontaneous occurring rare diseases in animals could help to understand the mechanism of similar diseases in human has well.

Lymphocyte activation markers in idiopathic myositis: changes with disease activity and differences among clinical and autoantibody subgroups

We studied the immunologic correlates of disease activity and differences among subgroups of patients with idiopathic inflammatory myopathy by analysing phenotypic and activation marker expression on peripheral blood mononuclear cells (PBMC). Compared with controls, myositis patients with clinically active disease (n = 51) had significantly lower proportions of CD8+ cells and higher proportions of PBMC that expressed DR, CD3- DR, CD14- DR, interleukin-2 receptors, and the late T cell activation markers CD26 and TLiSA1. TLiSA1 expression, a marker for cytotoxic differentiation, correlated significantly with both clinical activity indices and serum levels of muscle-associated enzymes. In serial studies of seven patients, the proportion of PBMC expressing MHC class II antigen and late T cell activation markers decreased as myositis disease activity decreased, independent of type of therapy. Among the clinical subgroups, polymyositis (n = 21) and inclusion body myositis (n = 11) were virtually indistinguishable; dermatomyositis patients (n = 19) showed decreased proportions of CD3+DR+ and TLiSA1+ cells, and increased proportions of CD20+ and CD20+DR+ cells compared with the other two groups. Patients with autoantibodies to histidyl-tRNA synthetase (Jo-1 antigen, n = 11) had significantly lower proportions of CD3+ and CD4+ cells, lower CD4/CD8 ratios, and higher proportions of CD+ cells expressing CD20, compared with patients without anti-Jo-1 antibodies. These findings support the concept that activated lymphocytes, especially cells undergoing anamnestic responses and cytotoxic differentiation, are important in the pathogenesis of idiopathic myositis. Moreover, taken together with other studies, these data suggest that groups of patients segregated by clinical or autoantibody status have different mechanisms of systemic immune activation and immunopathology.

Successful resection of dermatomyositis associated with thymic carcinoma: Report of a case

We report a case of thymic carcinoma associated with dermatomyositis (DM) in a 53-year-old man. The patient presented with the characteristic features of a skin rash with Gottron's papules, proximal muscle weakness, and increased serum levels of the muscle-associated enzymes. Comprehensive clinical examinations revealed an anterior mediastinal tumor. We resected the tumor and histological examination confirmed squamous cell carcinoma of the thymus. Thereafter, his clinical symptoms improved dramatically and his serum levels of muscle-associated enzymes dropped, indicating that the DM was a paraneoplastic phenomenon. Our search of the literature found only one other case report of DM accompanied by thymic carcinoma, and to our knowledge, this is the fi rst documented case of dramatic improvement of DM after resection of thymic carcinoma. We propose that thymic carcinoma should be added to the list of malignancies that can complicate DM as a paraneoplastic disease.

Myopathy with mitochondrial alterations in patients with primary biliary cirrhosis and antimitochondrial antibodies

To describe a syndrome of severe progressive myopathy, cardiomyopathy, and gastrointestinal dysmotility in 2 patients with asymptomatic primary biliary cirrhosis (PBC) and circulating antimitochondrial autoantibodies, and to review pertinent literature concerning this syndrome. Clinical, electrophysiologic, serologic, and pathologic studies of the 2 affected patients were conducted. Skeletal muscle involvement was manifested by progressive weakness of the proximal muscles, marked diaphragmatic dysfunction with consequent hypoventilation and respiratory failure, and moderately elevated levels of muscle-associated enzymes. Serum from both patients contained antimitochondrial antibodies that reacted with components of the mitochondrial keto acid dehydrogenase enzyme complex. Results of electromyography were consistent with a myopathic process. The microscopic and ultrastructural changes in the skeletal muscles were distinct from those of typical myositis, and were notable for striking subsarcolemmal aggregation of abnormal mitochondria in the absence of significant inflammation. Severe skeletal muscle, cardiac, and gastrointestinal pathology with abnormalities of the muscle mitochondria develops in a subset of patients with mild PBC and antimitochondrial antibodies. The pathogenesis of this syndrome is unclear, but may be related to the presence of the antimitochondrial autoantibodies.

The Treatment of Inclusion Body Myositis

We have sought to examine the response to immunosuppressive therapeutic intervention in inclusion body myositis (IBM) in a retrospective review of prior responses to therapy and in an open, randomized crossover trial. We collected information on the response to prior therapy on 25 patients, and for prospective therapy on 11 of these patients. All met criteria for a definite idiopathic inflammatory myopathy and had biopsy-proven IBM. Clinical and laboratory results were assessed by interviews of patients and by chart review in the retrospective trial. Manual muscle strength was assessed by a single trained observer; the patients' activities of daily living were assessed by questionnaire; and serum tests of muscle-associated enzymes were measured in the prospective trial. In the retrospective review, prednisone appeared to have been of some, albeit modest, clinical benefit in 10 of 25 (40%) patients. Other therapies, primarily azathioprine and methotrexate, also appeared to have halted the progression of weakness in 8 of 35 trials (23%). In the prospective study, combination therapy of oral azathioprine and methotrexate and a biweekly infusion of high-dose intravenous methotrexate with leucovorin rescue were given for 3 to 6 months in an open, crossover design. Both the oral and the intravenous regimens were clinically effective in some patients. There was clinical improvement in 3 trials, stabilization in 11 trials, and worsening in 5 trials, out of a total of 19 completed (22 intended) trials. The presence of active inflammation at entry into the prospective therapeutic protocol, either directly observed on muscle biopsy or indirectly indicated by serum creatine kinase level, may have been associated with clinical improvement. A complete laboratory response with normalization of creatine kinase and other muscle-associated enzymes did not, however, significantly predict clinical responsiveness in the prospective trial. In this first report, to our knowledge, of a prospective trial of immunosuppressive therapy for this disease, stabilization and even slight improvement of strength and functional abilities appeared to be achieved in some patients. We believe that prednisone and other immunosuppressive therapies were of modest benefit in about half of patients with inclusion body myositis, especially those with some evidence of active inflammation. Stabilization of an otherwise inexorably deteriorating course appears, therefore, to be an attainable goal in some patients with IBM.

Not Myositis

WEAKNESS, like fever or pain, accompanies so many conditions that the scope of its differential diagnosis is impossibly large. But when the answers to a few questions narrow the field to a complaint of muscle weakness, the differential shrinks (Table). In the illnesses called idiopathic inflammatory myositis—dermatomyositis, polymyositis, inclusion body myositis, and several rarer disorders—the patients are usually middleaged and have noticed the onset of weakness over weeks, months, or even years. The weakness most often affects proximal muscles so that climbing stairs, getting into or out of a car, lifting packages, combing the hair, or lifting the head off the pillow may be difficult. Muscle damage is shown by elevated serum levels of the muscle-associated enzymes, creatine kinase and aldolase; there are abnormalities on the electromyogram (EMG); and the muscle biopsy in most cases shows dying and regenerating muscle cells and an infiltrate of chronic inflammatory cells, predominantly lymphocytes.

Viral and host genetic factors influence encephalomyocarditis virus-induced polymyositis in adult mice.

Recent research findings implicate picornaviruses in the etiology of human polymyositis/dermatomyositis and suggest that genetic factors play a role in susceptibility to these diseases. We compared 2 variants of encephalomyocarditis (EMC) virus for their ability to induce polymyositis in adult mice, and evaluated what role the genetic background of the host plays in the degree of myositis induced. While BALB/c mice developed minimal myositis when infected with a diabetogenic variant (EMC-D), the same strain inoculated with a newly isolated myopathic variant (EMC-221A) developed viral dose-dependent elevations in muscle-associated enzymes, bilateral limb muscle weakness, and the histopathologic changes of severe polymyositis. Mice with different genetic backgrounds showed significantly different susceptibilities to EMC-221A. These data suggest that the severity of polymyositis induced by EMC virus is influenced by both the viral and host genomes.