The pattern of desmin filaments in myocardial disarray

Methanolic Extract of Phoenix Dactylifera Confers Protection against Experimental Diabetic Cardiomyopathy through Modulation of Glucolipid Metabolism and Cardiac Remodeling

The incidence of cardiovascular disorders is continuously rising, and there are no effective drugs to treat diabetes-associated heart failure. Thus, there is an urgent need to explore alternate approaches, including natural plant extracts, which have been successfully exploited for therapeutic purposes. The current study aimed to explore the cardioprotective potential of Phoenix dactylifera (PD) extract in experimental diabetic cardiomyopathy (DCM). Following in vitro phytochemical analyses, Wistar albino rats (N = 16, male; age 2-3 weeks) were fed with a high-fat or standard diet prior to injection of streptozotocin (35 mg/kg i.p.) after 2 months and separation into the following four treatment groups: healthy control, DCM control, DCM metformin (200 mg/kg/day, as the reference control), and DCM PD treatment (5 mg/kg/day). After 25 days, glucolipid and myocardial blood and serum markers were assessed along with histopathology and gene expression of both heart and pancreatic tissues. The PD treatment improved glucolipid balance (FBG 110 ± 5.5 mg/dL; insulin 17 ± 3.4 ng/mL; total cholesterol 75 ± 8.5 mg/dL) and oxidative stress (TOS 50 ± 7.8 H2O2equiv./L) in the DCM rats, which was associated with preserved structural integrity of both the pancreas and heart compared to the DCM control (FBG 301 ± 10 mg/dL; insulin 27 ± 3.4 ng/mL; total cholesterol 126 ± 10 mg/dL; TOS 165 ± 12 H2O2equiv./L). Gene expression analyses revealed that PD treatment upregulated the expression of insulin signaling genes in pancreatic tissue (INS-I 1.69 ± 0.02; INS-II 1.3 ± 0.02) and downregulated profibrotic gene expression in ventricular tissue (TGF-β 1.49 ± 0.04) compared to the DCM control (INS-I 0.6 ± 0.02; INS-II 0.49 ± 0.03; TGF-β 5.7 ± 0.34). Taken together, these data indicate that Phoenix dactylifera may offer cardioprotection in DCM by regulating glucolipid balance and metabolic signaling.

The Myocardial Accumulation of Aggregated Desmin Protein in a Case of Desminopathy with a de novo DES p.R406W Mutation

Desminopathy is a cardiac and skeletal myopathy caused by disease-causing variants in the desmin (DES) gene and represents a subgroup of myofibrillar myopathies, where cytoplasmic desmin-postive immunoreactivity is the pathological hallmark. We herein report a 28-year-old Japanese man who was initially diagnosed with sporadic hypertrophic cardiomyopathy with atrioventricular block at 9 years old and developed weakness in the soft palate and extremities. The myocardial tissue dissected during implantation of the ventricular-assisted device showed a dilated phase of hypertrophic cardiomyopathy and intracellular accumulation of proteinase K-resistant desmin aggregates. Genetic testing confirmed a de novo mutation of DES, which has already been linked to desminopathy. As the molecular diagnosis of desminopathy is challenging, particularly if patients show predominantly cardiac signs and a routine skeletal muscle biopsy is unavailable, these characteristic pathological findings of endomyocardial proteinase K-resistant desmin aggregates might aid in clinical practice.

A Cadaveric Evaluation of Hypertrophic Obstructive Cardiomyopathy

Hypertrophic obstructive cardiomyopathy (HOCM) describes a pathologic state in which the subaortic region of the interventricular septum undergoes significant hypertrophy and fibrosis, resulting in septal bowing into the left ventricle. The reduced left ventricular chamber size and altered cardiac function impair diastolic filling, stroke volume, and cardiac output. This case report evaluates the cardiac tissue of a 36-year-old, formalin-embalmed cadaver affected by HOCM, with the goal of providing a comprehensive overview of the gross and pathologic findings associated with the condition. This donor's heart was found to be larger than average, weighing 510.1 g, which is 52% heavier than the predicted value of 335.6 g for a male of similar stature. The thickness of the interventricular septum, right ventricular free wall, and left ventricular free wall was comparable to other reports of HOCM. However, asymmetrical thickening of the left ventricular walls, which is characteristic of HOCM, was less prominent than expected. Histologic staining of the cadaveric tissue, with hematoxylin and eosin, trichrome, and desmin, further bolstered the diagnosis. Importantly, this also showed that histologic examination of embalmed tissue is effective and diagnostic, even 11 months after embalming. The report herein demonstrates that morphologic and histologic analysis of cadaveric cardiac tissue is sufficient to support a diagnosis of HOCM. To the researchers' knowledge, this is the first case report evaluating HOCM in a cadaver donated for medical education.

On the toxicity of gold nanoparticles: Histological, histochemical and ultrastructural alterations

Gold nanoparticles (Au NPs) are used in diagnostic and therapeutic applications together with a variety of industrial purposes and in many biomedical sectors with potential risks to human health. The present study aimed to the histological, histochemical, and ultrastructural alterations induced by Au NPS in vital organs. Healthy male Wistar Albino rats (Rattus norvegicus) were subjected to 20 injections of 10-nm Au NPs at a daily dose of 2 mg/kg. Liver, kidney, heart, and lung biopsies from control and Au NPs-treated rats under study were subjected to histological and histochemical examinations. In comparison with the control rats, the renal tissue of Au NPs-treated rats demonstrated glomerular congestion, interstitial inflammatory cell infiltration, renal tubular hydropic degeneration, cloudy swelling, necrosis, and hyaline cast precipitation. In addition, Au NPs induced the following hepatic alterations: hepatocyte cytolysis, cytoplasmic vacuolation, hydropic degeneration, and nuclear alterations together with sinusoidal dilatation. Moreover, the hearts of the treated rats demonstrated myocarditis, cardiac congestion, hyalinosis, cardiomyocyte hydropic degeneration, myofiber disarray and cardiac congestion. The lungs of Au NPs-treated rats also exhibited the following pulmonary alterations: alectasis, emphysema, inflammatory cell inflammation, thickened alveolar walls, pulmonary interstitial edema, congestion, hypersensitivity, fibrocyte proliferation, and honeycombing. In conclusion, exposure to Au NPs induced histological, histochemical and ultrastructural alterations in the vital organs that may alter the function of these organs. Additional efforts are needed for better understanding the potential risks of Au NPs to human health.

Cardiac and testicular alterations induced by acute exposure to titanium dioxide nanoparticles: Histopathological study

Titanium dioxide nanoparticles (TiO₂ NPs) have novel application and are used in many household application, nanomedicine, agriculture, industries and pharmaceutical products. These applications may be accompanied with potential risk in human health and the ecosystems. The current study was carried out to find out the acute damage that might be induced by TiO₂ NPs in the heart and testis. Three groups of Wistar albino rats (Rattus norvegicus) were subjected to a single dose TiO₂ NPs (126, 252, 378 mg/kg bw). Cardiac and testicular biopsies from each animal under study were handled for histological and histochemical examination. Rats exposed to TiO₂ NPs demonstrated the following cardiac alterations: myofibres wavy appearance, myofibre disarray, partial cross striation, cardiomyocytes hydropic degeneration together with vacuolation and nuclear alterations. Moreover, acute exposure to TiO₂ NPs induced the following testicular alterations: spermatocytes degeneration, spermatids sloughing and interstitial edema. The presented cardiac and testicular alterations were dose dependent. From the findings of the present study, it might be concluded that TiO₂ nanomaterials are capable of inducing acute cardiac and testicular damage that is dose dependent and could adversely affect the function of the vital organs.

Divide and conquer: the application of organelle proteomics to heart failure

Chronic heart failure is a worldwide cause of mortality and morbidity and is the final outcome of a number of different etiologies. This reflects both the complexity of the disease and our incomplete understanding of its underlying molecular mechanisms. One experimental approach to address this is to study subcellular organelles and how their functions are activated and synchronized under physiological and pathological conditions. In this review, we discuss the application of proteomic technologies to organelles and how this has deepened our perception of the cellular proteome and its alterations with heart failure. The use of proteomics to monitor protein quantity and posttranslational modifications has revealed a highly intricate and sophisticated level of protein regulation. Posttranslational modifications have the potential to regulate organelle function and interplay most likely by targeting both structural and signaling proteins throughout the cell, ultimately coordinating their responses. The potentials and limitations of existing proteomic technologies are also discussed emphasizing that the development of novel methods will enhance our ability to further investigate organelles and decode intracellular communication.

Proteomic profiling of endothelin-1-stimulated hypertrophic cardiomyocytes reveals the increase of four different desmin species and alpha-B-crystallin

We performed a proteomic investigation on primary cultures of neonatal rat cardiomyocytes after treatment with 10 nM endothelin-1 (ET1) for 48 h, an in vitro model for cardiac hypertrophy. Two-dimensional gel electrophoresis profiles of cell lysates were compared after colloidal Coomassie Blue staining. 12 protein spots that significantly changed in density due to ET1 stimulation were selected for in-gel digestion and identified through mass spectrometry. Of these, 8 spots were increased and 4 were decreased. Four of the increased proteins were identified as desmin, the cardiac component of intermediate filaments and one as alpha-B-crystallin, a molecular chaperone that binds desmin. All the desmins increased 2- to 5-fold, and alpha-B-crystallin increased 2-fold after ET1 treatment. Desmin cytoskeleton has been implicated in the regulation of mitochondrial activity and distribution, as well as in the formation of amyloid bodies. Mitochondria-specific fluorescent probe MitoTracker indicated mitochondrial redistribution in hypertrophic cells. An increase of amyloid aggregates containing desmin upon treatment with ET1 was detected by filter assay. Of the four proteins that showed decreased abundance after ET1 treatment, the chaperones hsp60 and grp75 were decreased 13- and 9-fold, respectively. In conclusion, proteomic profiling of ET1-stimulated rat neonatal cardiomyocytes reveals specific changes in cardiac molecular phenotype mainly involving intermediate filament and molecular chaperone proteins.

Disease severity in dominant Emery Dreifuss is increased by mutations in both emerin and desmin proteins

Individuals with the same genetic disorder often show remarkable differences in clinical severity, a finding generally attributed to the genetic background. We identified two patients with genetically proven Emery-Dreifuss muscular dystrophy (EDMD) who followed an unusual course and had uncommon clinicopathological findings. We hypothesized digenic inheritance and looked for additional molecular explanations. Mutations in additional separate genes were identified in both patients. The first patient was a member of a family with molecularly proven X-linked EDMD. However, the clinical features were unusually severe for this condition in the propositus: he presented at 2.5 years with severe proximal weakness and markedly elevated serum creatine kinase. Muscle weakness rapidly progressed, leading to loss of independent ambulation by the age of 12. In addition, the patient developed cardiac conduction system disease requiring pacing at the age of 11 and severe dilated cardiomyopathy in the early teens. Despite pacing, he had several syncopal episodes attributed to ventricular dysrhythmias. As these resemble the cardiac features of patients with the autosomal dominant variant of EDMD, we examined the lamin A/C gene, identifying a de-novo mutation in the propositus. The second patient had a cardioskeletal myopathy, similar to his mother who had died more than 20 years previously. Because of the dominant family history, a laminopathy was suspected and a mutation in exon 11 of the LMNA gene was identified. This mutation, however, was not present in his mother, but instead, surprisingly, was identified in his virtually asymptomatic father. Unusual accumulations of desmin found in the cardiac muscle of the propositus prompted us to examine the desmin gene in this patient, and in so doing, we identified a desmin mutation, in addition to the LMNA mutation in the propositus. These cases suggest that separate mutations in related proteins that are believed to interact, or that represent different parts of a presumed functional pathway, may synergistically contribute to disease severity in autosomal dominant EDMD. Furthermore, digenic inheritance may well contribute to the clinical severity of many other neuromuscular disorders.

Altered cytoskeleton in smooth muscle of aganglionic bowel

CONTEXT

Intestinal motility is under the control of smooth muscle cells, enteric plexus, and hormonal factors. In Hirschsprung disease (HD), the aganglionic colon remains spastic or tonically enhanced and unable to relax. The smooth muscle cell's cytoskeleton consists of proteins or structures whose primary function is to link or connect protein filaments to each other or to the anchoring sites. Dystrophin is a subsarcolemmal protein with a double adhesion property, one between the membrane elements and the contractile filaments of the cytoskeleton and the other between the cytoskeletal proteins and the extracellular matrix. Desmin and vinculin are functionally related proteins that are present in the membrane-associated dense bodies in the sarcolemma of the smooth muscle cells.

OBJECTIVE

To examine the distribution of the cytoskeletal proteins in the smooth muscle of the aganglionic bowel.

DESIGN

Bowel specimens from ganglionic and aganglionic sections of the colon were collected at the time of pull-through surgery from 8 patients with HD. Colon specimens collected from 4 patients at the time of bladder augmentation acted as controls. Anti-dystrophin, anti-desmin, and anti-vinculin antibodies were used for fluorescein immunostaining using confocal laser scanning microscopy.

RESULTS

Moderate to strong dystrophin immunoreactivity was observed at the periphery of smooth muscle fibers in normal bowel and ganglionic bowel from patients with HD, whereas dystrophin immunoreactivity was either absent or weak in the smooth muscle of aganglionic colon. Moderate to strong cytoplasmic immunostaining for vinculin and desmin was seen in the smooth muscle of normal bowel and ganglionic bowel from patients with HD, whereas vinculin and desmin staining in the aganglionic colon was absent or weak.

CONCLUSION

This study demonstrates that the cytoskeletal proteins are abundant in the smooth muscle of normal bowel, but are absent or markedly reduced in the aganglionic bowel of HD. As cytoskeletal proteins are required for the coordinated contraction of muscle cells, their absence may be responsible for the motility dysfunction in the aganglionic segment.

[Genetically modified animal models in cardiovascular research]

It is a basic tenet of molecular and clinical medicine that specific protein complements underlie cell and organ function. Since cellular and ultimately organ function depend upon the polypeptides that are present, it is not surprising that when function is altered changes in the protein pools occur. In the heart, numerous examples of contractile protein changes correlate with functional alterations, both during normal development and during the development of numerous pathologies. Similarly, different congenital heart diseases are characterized by certain shifts in the motor proteins. To understand these relationships, and to establish models in which the pathogenic processes can be studied longitudinally, it is necessary to direct the heart to stably synthesize, in the absence of other peliotropic changes, the candidate protein. Subsequently, one can determine if the protein's presence causes the effects directly or indirectly with the goal being to define potential therapeutic targets. By affecting the heart's protein complement in a defined manner, one has the means to establish both mechanism and the function of the different mutated proteins of protein isoforms. Gene targeting and transgenesis in the mouse provides a means to modify the mammalian genome and the cardiac motor protein complement. By directing expression of an engineered protein to the heart, one is now able to effectively remodel the cardiac protein profile and study the consequences of a single genetic manipulation at the molecular, biochemical, cytological and physiologic levels, both under normal and stress stimuli.

Myocyte cytoskeletal disorganization and right heart failure in hypoxia-induced neonatal pulmonary hypertension

Previous studies have demonstrated that environmentally or genetically induced changes in the intracellular proteins that compose the cytoskeleton can contribute to heart failure. Because neonatal right ventricular myocytes are immature and are in the process of significant cytoskeletal change, we hypothesized that they may be particularly susceptible to pressure stress. Newborn calves exposed to hypobaric hypoxia (barometric pressure = 430 mmHg) for 14 days developed severe pulmonary hypertension (pulmonary arterial pressure = 101 +/- 6 vs. 27 +/- 1 mmHg) and right heart failure compared with age-matched controls. Light microscopy showed partial loss of myocardial striations in the failing neonatal right but not left ventricles and in neither ventricle of adolescent cattle dying of altitude-induced right heart failure. In neonatal calves, immunohistochemical analysis of the cytoskeletal proteins (vinculin, metavinculin, desmin, vimentin, and cadherin) showed selectively, within the failing right ventricles, patchy areas characterized by loss and disorganization of costameres and intercalated discs. Within myocytes from the failing ventricles, vinculin and desmin were observed to redistribute diffusely within the cytosol, metavinculin appeared in disorganized clumps, and vimentin immunoreactivity was markedly decreased. Western blot analysis of the failing right ventricular myocardium showed, compared with control, vinculin and desmin to be little changed in total content but redistributed from insoluble (structural) to soluble (cytosolic) fractions; metavinculin total content was markedly decreased, tubulin content increased, particularly in the structural fraction, and cadherin total content and distribution were unchanged. We conclude that hypoxic pulmonary hypertensive-induced neonatal right ventricular failure is associated with disorganization of the cytoskeletal architecture.

Desmin as a possible immunohistochemical marker for feline hypertrophic cardiomyopathy

Desmin has been suggested as a possible histopathological marker for hypertrophic cardiomyopathy (HCM) in humans. To test whether a similar pattern of desmin staining applies to HCM in cats, we conducted an immunohistochemical study on myocardial samples from 13 cats (HCM 4, other cardiomyopathies (OCM) 4, and control 5). The pattern of staining for desmin in HCM cats was not the same as that reported in humans, but was weaker than in OCM cats and controls. This suggested that desmin may be a possible histochemical marker for feline HCM, but our data was insufficient to clearly confirm this.

Properties of the novel intermediate filament protein synemin and its identification in mammalian muscle

We examined specific properties of highly purified synemin (230 kDa), recently identified as a novel intermediate filament (IF) protein, from avian smooth muscle. Soluble synemin in 10 mM Tris-HCl, pH 8.5, appears as approximately 11-nm-diameter globular structures by negative-stain and low-angle shadow electron microscopy. Chemical crosslinking and SDS-PAGE analysis indicate that soluble synemin molecules contain two 230-kDa subunits. The pH- and ionic strength-dependent solubility properties of synemin are similar to those of the type III IF protein desmin, but under physiological-like conditions in which desmin self-assembles into long approximately 10-nm-diameter IFs, synemin self-associates into complex, approx 15- to 25-nm-diameter globular structures. Calpain digestion demonstrated that synemin is extremely proteolytically labile. Western blot analysis, with monospecific polyclonal antibodies against avian synemin, shows the presence of the reactive 230-kDa synemin band in samples of adult avian skeletal, cardiac, and smooth muscle and of two reactive bands at approximately 225 kDa (major) and approximately 195 kDa in adult porcine skeletal, cardiac, and smooth muscle. Partial purification of synemin from porcine smooth muscle also resulted in fractions highly enriched in the approximately 225- and approximately 195-kDa polypeptides. Conventional immunofluorescence and immunoconfocal microscopy of isolated myofibrils and of frozen sections also demonstrated, for the first time, that synemin is present in all three adult porcine muscle cell types and is colocalized with desmin in skeletal and cardiac muscle cells at the myofibrillar Z-lines.

Restrictive cardiomyopathy, atrioventricular block and mild to subclinical myopathy in patients with desmin-immunoreactive material deposits

OBJECTIVES

We present clinical data and heart and skeletal muscle biopsy findings from a series of patients with ultrastructural accumulations of granulofilamentous material identified as desmin.

BACKGROUND

Desmin cardiomyopathy is a poorly understood disease characterized by abnormal desmin deposits in cardiac and skeletal muscle.

METHODS

Clinical evaluation, endomyocardial and skeletal muscle biopsy, light and electron microscopy and immunohistochemistry were used to establish the presence of desmin cardiomyopathy.

RESULTS

Six hundred thirty-one patients with primary cardiomyopathy underwent endomyocardial biopsy (EMB). Ultrastructural accumulations of granulofilamentous material were found in 5 of 12 biopsy samples from patients with idiopathic restrictive cardiomyopathy and demonstrated specific immunoreactivity with anti-desmin antibodies by immunoelectron microscopy. Immunohistochemical findings on light microscopy were nonspecific because of a diffuse intracellular distribution of desmin. All five patients had atrioventricular (AV) block and mild or subclinical myopathy. Granulofilamentous material was present in skeletal muscle biopsy samples in all five patients, and unlike the heart biopsy samples, light microscopic immunohistochemical analysis demonstrated characteristic subsarcolemmal desmin deposits. Two patients were first-degree relatives (mother and son); another son with first-degree AV block but without myopathy or cardiomyopathy demonstrated similar light and ultrastructural findings in skeletal muscle. Electrophoretic studies demonstrated two isoforms of desmin--one of normal and another of lower molecular weight--in cardiac and skeletal muscle of the familial cases.

CONCLUSIONS

Desmin cardiomyopathy must be considered in the differential diagnosis of restrictive cardiomyopathy, especially in patients with AV block and myopathy. Diagnosis depends on ultrastructural examination of EMB samples or light microscopic immunohistochemical studies of skeletal muscle biopsy samples. Familial desminopathy may manifest as subclinical disease and may be associated with abnormal isoforms of desmin.