Dysfunctional lamins as mediators of oxidative stress in Emery-Dreifuss muscular dystrophy.

Deficit of lamin A/C or emerin causes genetically transmitted Emery-Dreifuss muscular dystrophy (EDMD). As lamins are considered to be mediators of oxidative stress, the antioxidant/oxidant status was examined. The total oxidant/antioxidant status in serum was examined in 29 cases of Emery-Dreifuss muscular dystrophy. The study included 12 autosomal-dominant laminopathies (AD-EDMD), 17 X-linked emerinopathies (X-EDMD) and 20 age-matched normal subjects. Total oxidant status (TOS) was reduced in all cases, and the total antioxidant capacity (TAC) was found to be decreased in the majority of the patients (in 82.8%). A relationship between TOS level and disease progression was noted. No correlation between TOS/TAC level and cardiological or neurological parameters was detected. The results of the study indicate disturbances of redox balance in EDMD patients. Determination of TOS/TAC might help to assess the progress of the disease and the potential effectiveness of antioxidant therapy.

Tissue inhibitors of matrix metalloproteinases in serum are cardiac biomarkers in Emery-Dreifuss muscular dystrophy.

BACKGROUND: Tissue inhibitors of matrix metalloproteinases (TIMPs) are known to be involved in cardiovascular diseases. Hitherto, they have not been examined in dilated cardiomyopathy in the course of Emery-Dreifuss muscular dystrophy (EDMD). AIM: To define TIMPs in serum because they might help in defining cardiac dysfunction at the early cardiological stages of this disease and detect preclinical stages of cardiomyopathy. METHODS: Twenty-five EDMD patients connected with lamin A/C (AD-EDMD) or emerin (X-EDMD) deficiency and 20 healthy age-matched controls were examined. The serum levels of the tissue inhibitors TIMP-1, -2, -3 were quantified using the ELISA sandwich immunoassay procedure with appropriate antibodies. RESULTS: Serum levels of TIMP-1 were normal in autosomal AD-EDMD and increased in the majority of X-linked EDMD. The level of TIMP-2 was decreased in 25%/21% of AD-EDMD/X-EDMD cases. TIMP-3 serum level was significantly reduced in all the examined patients. Receiver operating curves indicated that in terms of sensitivity and specificity characteristics the performance of TIMP-3 (less that of TIMP-2) makes them the best markers of cardiac involvement among the examined TIMPs. CONCLUSIONS: Evidence shows that the levels of TIMP-3, and in some cases also TIMP-2, are decreased in EDMD. The decrease might be associated with an adverse effect on matrix metalloproteinases and remodelling of the myocardial matrix. The specific decrease of TIMP-3 indicates that this biomarker might help in early detection of cardiac involvement in EDMD. Up-regulation of TIMP-1 in the majority of patients with X-EDMD indicates increased myocardial extracellular matrix turnover, early onset of tissue remodelling, and may contribute to arrhythmia, frequently occurring in this form of the disease.

Tenascin-C in human cardiac pathology.

Tenascin-C (TN-C), a hexameric extracellular matrix glycoprotein, is a pleiotropic regulator of a variety of cell functions associated with embryogenesis, wound healing, cell proliferation, differentiation, motility, and nerve regeneration. Due to its role in remodeling processes, TN-C is involved with many pathologic states including cardiac and vascular diseases as well as inflammation and cancer. Assessment of circulating TN-C may help with identification of heart disease, especially in conjunction other cardiac biomarkers. It may be considered a specific biomarker useful in detecting cardiac pathology, especially in early disease stages and subsequent monitoring of cardiologic therapy. This review will highlight the biochemistry and usefulness of TN-C in clinical laboratory diagnostics to date.

[Myopathy in the course of carnitine palmitoyltransferase II deficiency]. / Miopatia w przebiegu niedoboru palmitylotransferazy karnityny II.

Congenital deficiency of carnitine palmitoyltransferase (CPT) II is a disease with an autosomal recessive inheritance of phenotypic variability which depends on age at the onset of symptoms. Three entities associated with deficiency of CPT II are known: the perinatal, the infantile and the adult form. The perinatal disease is the most severe form and is invariably fatal. On the other hand, the adult CPT II clinical phenotype is benign and requires additional external triggers such as high-intensity exercise to provoke myopathic symptoms. We report a case of adult CPT II deficiency presenting with the subtle symptoms of myopathy. A 32-year-old man was admitted to the hospital complaining of muscle pain after exercise. Athletic appearance drew attention, because the patient denied practicing sport. Neurological examination revealed marked tiredness during the single-leg hop test without other abnormalities. Electromyography (EMG) and serum biochemistry were not typical for myopathy. Routine histopathological examination did not reveal any abnormalities of structure of muscle fibers. Diagnosis was established after ultrastructural and biochemical analysis which revealed changes typical for CPT II deficiency.

Osteopontin--a fibrosis-related marker--in dilated cardiomyopathy in patients with Emery-Dreifuss muscular dystrophy.

BACKGROUND: As osteopontin (OPN) may be assumed to have diagnostic/prognostic value in heart diseases, it is worth assessing whether it is also involved in the pathogenesis and can be applied in the diagnosis of the dilated cardiomyopathy (DCM) in Emery-Dreifuss muscular dystrophy (EDMD). METHODS: Serum levels of osteopontin were quantified by means of sandwich immunoassay in 25 EDMD patients (10 laminopathies AD-EDMD and 15 emerinopathies--X-EDMD), eight carriers of X-EDMD, nine disease controls (patients with dystrophinopathy) and 20 age-matched healthy controls. RESULTS: The levels of circulating OPN were elevated in all AD-EDMD and X-linked EDMD patients, as well as in X-EDMD carriers and patients suffering progressive muscular dystrophy. There was no correlation between the osteopontin level and different cardiac parameters, including left-ventricular end-diastolic diameter, left atrial diameter, the left ventricular ejection fraction and the CK-MB level. There was a slight negative correlation with the ages of the patients. CONCLUSIONS: The presented results indicate that assessments of circulating OPN levels may help to identify EDMD patients at risk of dilated cardiomyopathy and might be therefore included among the set of biomarkers referred to with a view to appropriate early cardiologic diagnosis and therapy being commenced with in time.

Circulating tenascin-C levels in patients with dilated cardiomyopathy in the course of Emery-Dreifuss muscular dystrophy.

BACKGROUND: Tenascin-C (TN-C), an extracellular matrix glycoprotein, is of diagnostic and prognostic value in different heart diseases. One such dilated cardiomyopathy (DCM) with conduction disturbances is one of the most serious manifestations in Emery-Dreifuss muscular dystrophy (EDMD). Herein we therefore detail work to evaluate the potential significance of circulating TN-C in patients with EDMD, speculating that it may define the cardiac dysfunction, especially in patients who may be cardiac asymptomatic, but still be at risk of sudden death. MATERIAL AND METHOD: Serum levels of TN-C were quantified by sandwich immunoassay ELISA in 25 EDMD patients (10 with laminopathy-AD-EDMD and 15 with emerinopathy-X-EDMD), 8 X-EDMD carriers, 9 disease controls (patients with dystrophinopathy), and 15 age-matched healthy controls. Fourteen of the EDMD patients had repeated TN-C examinations after 3 to 7 years. RESULTS: The levels of circulating TN-C were elevated in AD-EDMD and X-EDMD patients, as well as in some X-EDMD carriers, and patients with dystrophinopathy. The correlation between the TN-C level and left end-systolic ventricle diameter (LVDD) was significant in X-EDMD, while those with left atrium diameter (LAD) and the ejection fraction (EF) were not. In "follow-up" studies TN-C levels were not found to change over time in AD-EDMD, while rising in X-EDMD. CONCLUSIONS: The presented results indicate that assessments of circulating TN-C levels may help to identify EDMD patients at risk of dilated cardiomyopathy. TN-C might therefore be considered a candidate for a new biomarker, useful in detecting of cardiomyopathy and in further monitoring of the DCM therapy in patients with EDMD.

Matrix metalloproteinases in serum of Emery-Dreifuss muscular dystrophy patients.

In the pathogenesis of dilated cardiomyopathy (DCM) in Emery-Dreifuss muscular dystrophy (EDMD) matrix metalloproteinases (MMPs) are supposed to be involved and may have diagnostic/prognostic value. Serum levels of MT1-MMP, MMP-2 and MMP-9 were quantified by ELISA and zymography in 22 EDMD patients and 15 age-matched controls. In the autosomal-dominant EDMD MMP-2 and MT1-MMP were increased in all cases, and MMP-9 was increased in two of the eight examined patients. In the X-linked EDMD MMP-2 expression was increased in all the cases, MMP-9 level was elevated in 3 of the 14 cases, and MT1-MMP was decreased in eight of these patients. There was no evident correlation between the MMPs level and the different cardiac parameters including left-ventricular end-diastolic diameter, left atrial diameter and left ventricular ejection fraction in either form of EDMD. The presented results indicate that a changed level of matrix metalloproteinases, especially that of MMP-2 in serum, may be of value for detection of cardiac involvement in EDMD patients, especially in those patients with no evident subjective cardiac symptoms. Further follow-up studies of MMPs are needed to check if their determination is of value for monitoring of the progression of atrial/ventricular dilatation. MMPs determinations may also be useful for monitoring DCM treatment by synthetic MMPs inhibitors.

[Detection of rare mutations in the dystrophin gene]. / Wykrywanie rzadkich mutacji w genie dystrofiny.

INTRODUCTION: Duchenne/Becker muscular dystrophies (DMD/BMD) are allelic X-linked, recessive proximal muscle disorders, caused by mutations in the dystrophin gene located in Xp21. DMD occurs with the incidence 1:3500, BMD with the incidence of 1:18,500 new-born males. Approximately about 60% of mutations in the dystrophin gene are deletions, 10%--duplications and 30%--point mutations. AIM: The aim of the study was detection of the mutations: rare deletions, duplications and point mutations in the dystrophin gene in patients diagnosed as DMD/BMD in whom the presence of the most common deletions had previously been excluded. MATERIALS AND METHODS: Molecular analysis was performed using DNA samples isolated from 105 DMD and 10 BMD patients. Detection of rare deletions and duplications was carried out by Multiplex Ligation-dependent Probe Amplification (MLPA). Point mutations were identified by analysis of single strand conformation polymorphism (SSCP) and DNA sequencing. RESULTS: 38 Different mutations were detected: 10 rare deletions, 14 duplications and 14 point mutations and microdeletions. Majority of the detected rare deletions (7 out of 10) and point mutations (11 out of 14) are novel mutations. CONCLUSIONS: Application of MLPA technique allows the detection of small, rare deletions and duplications. Identification of the nature and localization of the mutations may, in the future, help to apply appropriate therapeutic approaches in DMD patients.

Progeria caused by a rare LMNA mutation p.S143F associated with mild myopathy and atrial fibrillation.

We present a 6-year-old girl with premature aging associated with mild myopathy, displaying muscle weakness, joint contractures and hyporeflexia. Genetic analysis revealed rare heterozygous point mutation in lamin A/C gene, g.428C>T. Cardiological evaluation showed atrial fibrillation, but we did not find signs of coronary heart disease, which is life-threatening cardiovascular complication in progeria. Electron microscopy of the muscle revealed abnormalities in nuclear architecture, i.e. blebbing, thick lamina and peripheral distribution of heterochromatin. As some diagnostic criteria characteristic for classic progeria are not fulfilled, this case could be regarded as atypical progeria associated with myopathy and atrial fibrillation. To our knowledge, this is the second case of such association described in the literature.

Myelin composition of spinal cord in a model of amyotrophic lateral sclerosis (ALS) in SOD1G93A transgenic rats.

We present the results of biochemical and electron microscopic (EM) examinations of the spinal cord myelin from SOD1G93A transgenic Sprague Dawley rats in the early and late symptom-free period of the disease (60 and 93 days of life) and after four-leg paralysis has occurred (120 days of life). Biochemical and ultrastructural changes of myelin started already in the symptom-free period and become most pronounced in the paralyzed animals. Biochemical examinations indicated a decrease of lipids, phospholipids, cholesterol and cerebrosides. The pattern of particular phospholipids was in the normal range. A progressive decrease of the percentages of proteolipid, DM-20 and Wolfgram proteins was evident. Myelin basic proteins I and II were less affected. In EM,massive myelin disorganization was observed.

Auto-antibodies against proteins of spinal cord cells in cerebrospinal fluid of patients with amyotrophic lateral sclerosis (ALS).

Aetiology and pathogenesis of amyotrophic lateral sclerosis (ALS) is still a mystery. Among several hypotheses autoimmune mechanisms are also taken into account. We report here our investigations of auto-antibodies against proteins of spinal cord cells in the cerebrospinal fluid (CSF) and serum of ALS patients. The results were correlated with the severity of disease course. The subjects were 57 ALS patients (29 severe, 28 mild) and 10 normal controls. The major finding in CSF was the presence of antibodies against a 70 kD protein in the majority of ALS patients. This protein was identified as neurofilament 68. The second protein of high reactivity and frequency of appearance was a 82 kD protein, which was identified as a-actinin. Less reactive and less frequent were antibodies directed against 55 kD and 40 kD proteins. They were immunologically defined to be related to desmin and actin, resp. The difference between the reactivity of anti-neurofilament and anti-desmin related protein in the severe and mild ALS groups was significant. More frequent were the anti-neurofilament antibodies in the severe ALS cases as compared to the milder ones. In normal CSF, antibodies directed against 55 kD, 70 kD and 82 kD proteins were present in traces and appeared in 5%, 20% and 10% of cases, respectively. In the serum of 30% of severe ALS patients traces of antibodies against 70 kD protein were detected. The morphological studies in the presence of CSF of ALS patients revealed pronounced immunoreactivity of spinal cord neurons, mainly within anterior horns. The significance of the presence of auto-antibodies in CSF of ALS patients against cellular proteins of the spinal cord is hard to define. It is conceivable that they appear as a secondary immunological consequence of neuronal death. It is also possible that they may accelerate the course of neuronal degeneration.

The involvement of oxidative stress in determining the severity and progress of pathological processes in dystrophin-deficient muscles.

In both forms of muscular dystrophy, the severe Duchenne's muscular dystrophy (DMD) with lifespan shortened to about 20 years and the milder Becker dystrophy (BDM) with normal lifespan, the gene defect is located at chromosome locus Xp21. The location is the same in the experimental model of DMD in the mdx mice. As the result of the gene defect a protein called dystrophin is either not synthesized, or is produced in traces. Although the structure of this protein is rather well established there are still many controversies about the dystrophin function. The most accepted suggestion supposes that it stabilizes sarcolemma in the course of the contraction-relaxation cycle. Solving the problem of dystrophin function is a prerequisite for introduction of an effective therapy. Among the different factors which might be responsible for the appearance and progress of dystrophic changes in muscles there is an excessive action of oxidative stress. In this review data indicating the influence of oxidative stress on the severity of the pathologic processes in dystrophy are discussed. Several pieces of data indicating the action of oxidative damage to different macromolecules in DMD/BDM are presented. Special attention is devoted to the degree of oxidative damage to muscle proteins, the activity of neuronal nitric oxide synthase (nNOS) and their involvement in defining the severity of the dystrophic processes. It is indicated that the severity of the morbid process is related to the degree of oxidative damage to muscle proteins and the decrease of the nNOS activity in muscles. Estimation of the degree of the destructive action of oxidative stress in muscular dystrophy may be a useful marker facilitating introduction of an effective antioxidant therapy and regulation of nNOS activity.

Oxidative damage to proteins in the spinal cord in amyotrophic lateral sclerosis (ALS).

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, which has been linked to the generation of free radicals and oxidative stress. Oxidative damage to spinal cord proteins is suggested to be a contributory factor to neuronal death in ALS. Since proteins are the major targets for free radicals and the so-called "reactive species", therefore the objective of our study was to identify oxidatively damaged spinal cord proteins. The material consisted of spinal cords of 8 sporadic ALS cases and 5 controls. We estimated the level of protein carbonyl moieties, which react quantitatively with 2,4-dinitrophenylhydrazine (DNPH). Afterwards proteins were separated by SDS-polyacrylamide gel electrophoresis and the protein bound DNPH moieties were detected immunochemically. We also morphologically examined spinal cords after immune staining against DNPH. The protein carbonyl content of the ALS spinal cords significantly increased in all examined cases. In most ALS patients, proteins with 125 kDa, 70 kDa and 36kDa were highly oxidized. The 70-kDa protein was identified immunochemically to be neurofilament 68. The morphological examination of ALS spinal cords indicated a pronounced anti-DNPH immune reaction in neurones of the anterior horns; the reaction in the posterior horns was less intense. Microglia in the white matter was immunoreactive; astroglia was DNPH-negative. Although the exact mechanism by which reactive oxygen species induce motor neurones to die is not known yet, the presented data indicate that they affect spinal cord cellular proteins, including neurofilament 68. In this study, we successfully examined the neurochemical features accompanying motor neuron injury in ALS, and the results may help to develop a rationale anti-oxidative neuroprotective strategy.

Is the normal content of sulfhydryl groups attributable to sparing from dystrophic pathology in dystrophin-deficient muscles?

Deficiency of dystrophin in skeletal muscles is supposed to be responsible for all the symptoms associated with Duchenne dystrophy (DMD) and Becker dystrophy (BMD). The dystrophin-deficient mdx mice, however, are clinically almost asymptomatic. Hence, other factor(s) might be responsible for the muscle pathology in DMD and BDM. As sulfhydryl groups are involved in maintaining the structure of membranes and the protein-phospholipid interactions, total, protein-bound and free sulfhydryl groups (-SH) in DMD, BMD, limb-girdle dystrophy (LGMD) and the mdx mice muscles have been determined. A significant decrease of total and protein-bound -SH groups content and an increased proportion of free -SH groups in DMD and BMD was found. In LGMD the changes of total and protein-bound -SH groups content were less expressed. In the mdx mice muscles the content of -SH groups was generally normal, only a higher than normal proportion of free-SH groups content in old and senile animals, especially in their diaphragm, was present. To test the sarcolemmal integrity, albumin/creatine kinase (CK) influx/efflux was determined. In early stages of DMD and BMD the albumin influx was increased. In advanced stages of these diseases albumin influx was not observed. In LGMD albumin penetration was present only in a few fibres. CK efflux in vitro was increased both in early and advanced DMD cases. In BMD and LGMD CK efflux was increased only in early stages of the diseases. In mdx mice an increased influx/efflux of albumin/CK was stated in adult animals. The changes persisted in the mdx hind limb muscles up to the senile age of the animals. In the mdx diaphragm of senile animals albumin did not penetrate the muscle cell and no increase of CK efflux was observed. It is suggested that changes in the distribution of -SH groups take part in the molecular disorganisation of the sarcolemma in course dystrophinopathies. Normal content of the sulfhydryl groups is supposed to be attributable to sparing from dystrophic pathology in dystrophin-deficient mdx mice muscles.