A case of idiopathic myocardiopathy with deposits of a peculiar substance in the myocardium; diagnosis by endomyocardial biopsy

The enlarging spectrum of desminopathies: new morphological findings, eastward geographic spread, novel exon 3 desmin mutation

A 52-year-old man, who had developed distal muscle weakness in legs and arms, was found to have distal muscle atrophy as well as cardiac arrhythmia. His 10-year younger brother developed restrictive cardiomyopathy at the age of 20 years, which required cardiac transplantation at the age of 41 years. Skeletal muscle biopsy specimens of the older brother revealed granulofilamentous material and plaques containing numerous proteins, foremost desmin, as did cardiac biopsy tissue. The explanted heart of the younger brother showed similar protein-rich plaques and granulofilamentous material within cardiac myocytes. A novel heterozygous Glu245Asp (E245D) missense mutation in exon 3 of the desmin gene (DES) at 2q35 was found in the older brother. While clinical data and muscle biopsy pathology of the older brother conform to the nosological spectrum of desminopathies, the early-onset cardiomyopathy, a similar cardiac pathology as in skeletal muscle tissues and a novel missense mutation in the DES gene, enlarge the nosological spectrum of desminopathies.

Desmin myopathy involving cardiac, skeletal, and vascular smooth muscle: report of a case with immunoelectron microscopy

Desmin myopathy is a rare idiopathic disorder characterized by abnormal aggregates of desmin-type intermediate filaments, which affects cardiac and skeletal muscle, and rarely the intestinal smooth muscle. We report a 42-year-old woman with atrial fibrillation and progressive restrictive cardiomyopathy. Left ventricular biopsy, cardiac explant, and subsequent autopsy study of skeletal muscle revealed cytoplasmic granulo-filamentous inclusions that were continuous with Z-lines and were immunoreactive for desmin filaments both at the light immunohistochemical and electron microscopic level. In addition, we report the presence of characteristic inclusions within the smooth muscle of intramural coronary blood vessels. This is the first description of desmin inclusions within vascular smooth muscle, and underscores the systemic nature of this rare myopathy.

Desmin myopathy: a multisystem disorder involving skeletal, cardiac, and smooth muscle

Myopathy associated with desmin-type intermediate filaments is an uncommon disorder of skeletal and/or cardiac muscle. The present study focuses on a 28-year-old man with generalized muscular atrophy, cardiomyopathy, and intestinal malabsorption and pseudo-obstruction. Abundant sarcoplasmic granular and filamentous aggregates that were ultrastructurally continuous with Z lines or dense bodies and exhibited intense immunostaining for desmin were present throughout the skeletal musculature, myocardium, and smooth muscle of the intestine. Moreover, neurofilament-immunoreactive axonal spheroids were identified in the spinal cord and roots. These widely distributed findings illustrate the multisystemic character of desmin myopathy, which in this instance first adds intestinal smooth muscle involvement to its already known skeletal and cardiac muscle manifestations. The additional presence of neurofilament aggregates in the spinal cord and roots constitutes an extremely rare conjunction of intermediate filament pathology of the neuromuscular system.

Neuromyopathy and restrictive cardiomyopathy with accumulation of intermediate filaments: a clinical, morphological and biochemical study

The clinical, morphological and biochemical findings of a sporadic case, showing accumulation of desmin-type intermediate filaments in skeletal muscle and myocardium are described. Desmin storage was demonstrated by immunofluorescence, sodium dodecyl sulfate gel electrophoresis and two-dimensional gel electrophoresis. These findings are in agreement with those of Rappaport et al. (FEBS lett. 231:421-425, 1989). A sensory-motor polyneuropathy was established by electrophysiological studies and, ultrastructurally, intramuscular nerves showed accumulation of neurofilaments and neurotubules with formation of axonal spheroids. These findings are discussed considering all previous reports with related conditions.

Cardiomyopathy characterized by abnormal accumulation of desmin-type intermediate filaments in cardiac muscle fibers. A case report and review of the literature

A 42-year-old Japanese male, who had been suffering from congestive heart failure and electrocardiographic abnormalities (A-V block, intraventricular conduction disturbance, ventricular tachycardia), died after a clinical course of 2 years and 1 month. Macroscopic investigation revealed dilation of the left ventricle and thickening of the right ventricular wall. The unique finding in this case was a circumferential fibrous scar in the median circular layer and outer oblique layer of the left ventricular wall. Biopsy and autopsy materials revealed diffuse loss of myofibrils in the central zone of cardiac muscle fibers, and replacement with aniline blue-positive homogeneous material (17-35% of the area of one muscle fiber). Electron microscopy revealed abnormal accumulation of fine filamentous material (7.5-25 nm in diameter), which was immunohistochemically proved to be desmin-type intermediate filament. Moreover, sarcoplasmic reticulum-like material was detected in the degenerated area. At autopsy, degeneration was detected all over the heart. The ventricular muscle fibers were more severely affected than the atrial muscle fibers. The conduction system was also affected, in some parts more severely than the surrounding ordinary muscle fibers. The pathogenesis of this disorder remains to be clarified.

Myopathy associated with desmin type intermediate filaments. An immunoelectron microscopic study

The muscle biopsy performed in a 58-year-old woman with a myopathy involving pelvic girdle and lower limbs displayed unusual intermediate filament aggregates by light and electron microscopy. No cardiac involvement was detected. The filamentous aggregates selective for type 1 fibers were found in subsarcolemmal and intermyofibrillar areas closely related to Z bands. Immunohistochemical study by light and electron microscopy using polyclonal and monoclonal antibodies and avidin-biotin peroxidase method revealed that aggregates consisted of desmin filaments. Desmin positive material was unstained with vimentine antibodies.

Histopathological observation of the heart with diffuse and abnormal proliferation of mitochondria in myocardial cells (mitochondrial cardiomyopathy): report of an adult case

An autopsy case of idiopathic dilated cardiomyopathy with abnormal proliferation of mitochondria in the myocardial cells is reported. The case is that of a 39-year-old male with congestive heart failure. The heart was 700 g and showed marked dilatation of all cardiac chambers with myocardial fibrosis of the left ventricular myocardium and interventricular septum, especially in the basal portion of the left ventricular posterior wall. Myocardial cells were hypertrophied with a marked increase of fine-granular sarcoplasm, containing numerous mitochondria, seen by electron microscopy. The mitochondria were usually round or oval and ranged in size from 0.3 to 1.2 micron in diameter. The cristae of these mitochondria frequently showed a concentric lamellar or reticular configuration. Myofibrils were unusually scarce, but the sarcomere structure and arrangement of myofilaments were well-preserved. Epicardial and intramural coronary vessels were almost normal. From these findings, we consider this to be an adult case of mitochondrial cardiomyopathy.

Unusual familial cardiomyopathy with storage of intermediate filaments in the cardiac muscular cells

Unusual histological and ultrastructural changes in cardiac muscle cells have been found in 3 brothers with progressive myocardial deficiency. Histologically, this cardiomyopathy was characterized by massive storage of PAS-negative proteinaceous material in most cardiac muscle cells. The electron microscope showed that this material consisted of sinuous filaments, 7-10 nm in diameter, similar to the intermediate filaments normally present in cardiac muscle cells. Filament storage coincided with the disintegration of neighbouring myofibrils, with particular change in Z bands giving rise to rod-like bodies and more complex structures formed by the association of Z band material and sarcoplasmic reticulum (SR) tubules. Filament storage and myofibrillar disintegration always occurred in areas where the SR developed and involuted extensively. Relatively high glycogen accumulation also occurred, in close relation to the SR changes. Discrete SR proliferation, glycogen overload and filament deposits were observed in a few skeletal fibres. These observations suggest that disturbance in the metabolism of desmin (protein subunit of intermediate filaments and a fundamental component of Z bands) might be involved in this type of cardiomyopathy. The influence of a chronic defect in calcium regulation might also be envisaged in view of the marked SR abnormalities.

Effectiveness and hazard of endomyocardial biopsy in dogs: comparison of two methods

Two different methods of endomyocardial biopsy were evaluated. Compared to the Konno bioptome, a technique using a biopsy forceps originally designed for fiberoptic bronchoscopy and bronchial biopsy, passed through a No. 9 Fr. end-hole catheter, was easier to perform. The biopsy device is smaller than the Konno bioptome, has sharper teeth, and is easier to clean. The two techniques did not differ in arrhythmogenicity, hemorrhagic changes in the myocardium, or distortion of the specimens. Ventricular tachycardia as defined by three beats in a row was observed in 34 per cent. Epicardial hemorrhage was seen in nine of 14 animals, and the specimen distortion rate was 43 per cent. In one animal, perforation of the right ventricle and hemopericardium occurred.