Desmin interacts with STIM1 and coordinates Ca2+ signaling in skeletal muscle

Stromal interaction molecule 1 (STIM1), the sarcoplasmic reticulum (SR) transmembrane protein, activates store-operated Ca2+ entry (SOCE) in skeletal muscle and, thereby, coordinates Ca2+ homeostasis, Ca2+-dependent gene expression, and contractility. STIM1 occupies space in the junctional SR membrane of the triads and the longitudinal SR at the Z-line. How STIM1 is organized and is retained in these specific subdomains of the SR is unclear. Here, we identified desmin, the major type III intermediate filament protein in muscle, as a binding partner for STIM1 based on a yeast 2-hybrid screen. Validation of the desmin-STIM1 interaction by immunoprecipitation and immunolocalization confirmed that the CC1-SOAR domains of STIM1 interact with desmin to enhance STIM1 oligomerization yet limit SOCE. Based on our studies of desmin-KO mice, we developed a model wherein desmin connected STIM1 at the Z-line in order to regulate the efficiency of Ca2+ refilling of the SR. Taken together, these studies showed that desmin-STIM1 assembles a cytoskeletal-SR connection that is important for Ca2+ signaling in skeletal muscle.

The role of intermediate filaments in maintaining integrity and function of intestinal epithelial cells after massive bowel resection in a rat

PURPOSE

Intermediate filaments (IFs) are a part of the cytoskeleton that extend throughout the cytoplasm of all cells and function in the maintenance of cell-shape by bearing tension and serving as structural components of the nuclear lamina. In normal intestine, IFs provide a tissue-specific three-dimensional scaffolding with unique context-dependent organizational features. The purpose of this study was to evaluate the role of IFs during intestinal adaptation in a rat model of short bowel syndrome (SBS).

MATERIALS AND METHODS

Male rats were divided into two groups: Sham rats underwent bowel transection and SBS rats underwent a 75% bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's Digital Gene Expression (DGE) analysis was used to determine the cytoskeleton-related gene expression profiling. IF-related genes and protein expression were determined using real-time PCR, Western blotting and immunohistochemistry.

RESULTS

Massive small bowel resection resulted in a significant increase in enterocyte proliferation and concomitant increase in cell apoptosis. From the total number of 20,000 probes, 16 cytoskeleton-related genes were investigated. Between these genes, only myosin and tubulin levels were upregulated in SBS compared to sham animals. Between IF-related genes, desmin, vimentin and lamin levels were down-regulated and keratin and neurofilament remain unchanged. The levels of TGF-β, vimentin and desmin gene and protein were down-regulated in resected rats (vs sham animals).

CONCLUSIONS

Two weeks following massive bowel resection in rats, the accelerated cell turnover was accompanied by a stimulated microfilaments and microtubules, and by inhibited intermediate filaments. Resistance to cell compression rather that maintenance of cell-shape by bearing tension are responsible for contraction, motility and postmitotic cell separation in a late stage of intestinal adaptation.

Drug use to resistance exercise-induced fatigue based on diclofenac diethylamine emulgel efficacy analysis

In this paper, the author study on the effect of drug treatment on sports injury, and makes a comparative analysis of drug effects. In sports, the incidence of various types of injuries is increasing, especially in muscle injury. In the experiment, we compared the effects of three different drugs on the treatment and relief of muscle loss. After 3 weeks, the average optical density of desmin in muscle fiber positive region have decreased, as xiaotong plaster (0.4708±0.0126), votalin (0.5124±0.0264) and placebo (0.3856±0.0312). It has a certain effect to promote the repair and regeneration of desmin expression by drugs. Through the analysis of the effect of drug intervention on sports injury repair, we can effectively improve the therapeutic effect of sports injury.

Immunohistochemical Characterization of Cloned Lamb Nephropathy

Kidneys from lambs derived by nuclear transfer are frequently abnormal and are characterized by an enlarged pelvis and narrow medulla, consistent with lower urinary tract obstruction and development of variable hydronephrosis. The precise pathogenesis of this entity is unknown. Immunohistochemical staining for intermediate filaments was used to further characterize the lesions seen in this condition and was compared with age-matched control tissue. Major findings were upregulation of cytokeratin on damaged tubules, desmin and vimentin in undifferentiated mesenchyme, and smooth muscle actin in mesenchyme and on smooth muscle “collars” around dilated tubules. In addition, some cases showed reexpression of vimentin and desmin on proximal tubular epithelial cells. Taken together, these findings provide a valuable database for tracking the expression of intermediate filaments throughout renal development in sheep and have further characterized the nature of the response to injury by the developing kidney, a response that is characterized by proliferation of mesenchyme and both reexpression and upregulation of intermediate filaments within renal cells. In addition, the study has confirmed that the changes in cloned lamb nephropathy are established by day 85 of development.

[EFFECT OF SHORT-TERM DRY IMMERSION ON PROTEOLYTIC SIGNALING IN HUMAN SOLEUS MUSCLE]

The signaling processes initiating proteolytic events in m. soleus of humans during short-term exposure in the non-weight bearing conditions were analyzed. Dry immersion (DI) was used to induce weight deprivation over 3 days. Western blotting was used to define the IRS-1 content, total and phosphorylated neuronal NO-synthase (nNOS), AMP-activated protein kinase (AMPK) that control the anabolic and catabolic pathways, and concentrations of cytoskeletal protein desmin and Ca²⁺-activated protease calpin. Already on day-3 of DI calpain-dependent proteolysis manifests itself by reductions in both the total content and level of nNOS phosphorilation. Moreover, AMPK phosphorilation was decreased drastically.

Histopathological and Immunohistochemical Evaluation of Pannus Tissue in Patients with Prosthetic Valve Dysfunction

BACKGROUND

Prosthetic valve dysfunction due to pannus formation is a rare but serious complication. Currently, limited data are available concerning the pathogenesis and immunohistochemical properties of pannus. The study aim was to investigate the morphological, histopathological and immunohistochemical characteristics of pannus formation in patients with prosthetic valve dysfunction.

METHODS

A total of 35 patients (10 males, 25 females; mean age 44 ± 16 years) who had undergone re-do valve surgery due to prosthetic valve obstruction was enrolled in the study. Immunohistochemical studies were aimed at evaluating the expression of alphasmooth muscle actin (α-SMA) and desmin in myofibroblasts and smooth muscle cells; epithelial membrane antigen (EMA) in epithelial cells; and CD34, Factor VIII and vascular endothelial growth factor (VEGF) in endothelial cells. Matrix metalloproteinases (MMPs) -2 and -9, and transforming growth factor-beta (TGF-β) were used to demonstrate cytokine release from macrophages, leukocytes, fibroblasts and myofibroblasts.

RESULTS

Pannus appeared as a tough and thick tissue hyperplasia which began from outside the suture ring in the periannular region and extended to the inflow and outflow surfaces of the prosthetic valves. Histopathological analysis showed the pannus tissue to consist of chronic inflammatory cells (lymphocytes, plasma cells, macrophages and foreign body giant cells), spindle cells such as myofibroblasts, capillary blood vessels and endothelial cells laying down the lumens. Calcification was present in the pannus tissue of 19 explanted prostheses. Immunohistochemical studies revealed positive α-SMA expression in all patients, whereas 60.5% of patients were positive for desmin, 50% for EMA, 42.1% for VEGF, 39.5% for TBF-β, 42.1% for MMP-2, 86.8% for CD34, and 97.4% for Factor VIII. MMP-9 was negative in all patients.

CONCLUSIONS

Pannus tissue appears to be formed as the result of a neointimal response in periannular regions of prosthetic valves that consist of periannular tissue migration, myofibroblast and extracellular matrix proliferation with vascular components. It is a chronic active process in which mediators such as TGF-β, VEGF and MMP-2 play roles in both matrix formation and degradation.

Improved neurological outcome by intramuscular injection of human amniotic fluid derived stem cells in a muscle denervation model

Purpose

The skeletal muscle develops various degrees of atrophy and metabolic dysfunction following nerve injury. Neurotrophic factors are essential for muscle regeneration. Human amniotic fluid derived stem cells (AFS) have the potential to secrete various neurotrophic factors necessary for nerve regeneration. In the present study, we assess the outcome of neurological function by intramuscular injection of AFS in a muscle denervation and nerve anastomosis model.

Materials and Methods

Seventy two Sprague-Dawley rats weighing 200–250 gm were enrolled in this study. Muscle denervation model was conducted by transverse resection of a sciatic nerve with the proximal end sutured into the gluteal muscle. The nerve anastomosis model was performed by transverse resection of the sciatic nerve followed by four stitches reconnection. These animals were allocated to three groups: control, electrical muscle stimulation, and AFS groups.

Results

NT-3 (Neurotrophin 3), BDNF (Brain derived neurotrophic factor), CNTF (Ciliary neurotrophic factor), and GDNF (Glia cell line derived neurotrophic factor) were highly expressed in AFS cells and supernatant of culture medium. Intra-muscular injection of AFS exerted significant expression of several neurotrophic factors over the distal end of nerve and denervated muscle. AFS caused high expression of Bcl-2 in denervated muscle with a reciprocal decrease of Bad and Bax. AFS preserved the muscle morphology with high expression of desmin and acetylcholine receptors. Up to two months, AFS produced significant improvement in electrophysiological study and neurological functions such as SFI (sciatic nerve function index) and Catwalk gait analysis. There was also significant preservation of the number of anterior horn cells and increased nerve myelination as well as muscle morphology.

Conclusion

Intramuscular injection of AFS can protect muscle apoptosis and likely does so through the secretion of various neurotrophic factors. This protection furthermore improves the nerve regeneration in a long term nerve anastomosis model.

Myogenic progenitors and imaging single-cell flow analysis: a model to study commitment of adult muscle stem cells

Research on skeletal muscles suffers from a lack of appropriate human models to study muscle formation and regeneration on the regulatory level of single cells. This hampers both basic understanding and the development of new therapeutic approaches. The use of imaging multicolour flow cytometry and myogenic stem cells can help fill this void by allowing researchers to visualize and quantify the reaction of individual cultured cells to bioactives or other physiological impulses. As proof of concept, we subjected human CD56+ satellite cells to reference bioactives follistatin and Malva sylvestris extracts and then used imaging multicolor flow cytometry to visualize the stepwise activation of myogenic factors MyoD and myogenin in individual cells. This approach enabled us to evaluate the potency of these bioactives to stimulate muscle commitment. To validate this method, we used multi-photon confocal microscopy to confirm the potential of bioactives to stimulate muscle differentiation and expression of desmin. Imaging multicolor flow cytometry revealed statistically significant differences between treated and untreated groups of myogenic progenitors and we propose the utilization of this concept as an integral part of future muscle research strategies.

[Desmin content and transversal stiffness of the left ventricle mouse cardiomyocytes and skeletal muscle fibers after a 30-day space flight on board "BION-M1" biosatellite]

The aim of this study was to determine the transversal stiffness of the cortical cytoskeleton and the cytoskeletal protein desmin content in the left ventricle cardiomyocytes, fibers of the mouse soleus and tibialis anterior muscle after a 30-day space flight on board the "BION-M1" biosatellite (Russia, 2013). The dissection was made after 13-16.5 h after landing. The transversal stiffness was measured in relaxed and calcium activated state by, atomic force microscopy. The desmin content was estimated by western blotting, and the expression level of desmin-coding gene was detected using real-time PCR. The results indicate that, the transversal stiffness of the left ventricle cardiomyocytes and fibers of the soleus muscle in relaxed and activated states did not differ from the control. The transversal stiffness of the tibialis muscle fibers in relaxed and activated state was increased in the mice group after space flight. At the same time, in all types of studied tissues the desmin content and the expression level of desmin-coding gene did not differ from the control level.

Significance of low desmin expression in cardiomyocytes in patients with idiopathic dilated cardiomyopathy

Desmin plays an essential role in maintaining cell cytoarchitecture, positioning and functioning of organelles, and the intercellular signaling pathway. It has been suggested that remodeling of desmin cytoskeleton might contribute to the progression of idiopathic dilated cardiomyopathy and might affect patients' long-term prognosis. We performed endomyocardial biopsy in 200 patients with idiopathic dilated cardiomyopathy. A total of 5 to 6 specimens were collected from the left ventricular (LV) wall. Desmin was detected with immunohistochemical staining and Western blotting. Immunohistochemistry revealed 4 types of desmin expression: I, normal staining at Z-lines and intercalated disks, giving a regular cross-section pattern; IIA, increased desmin staining at Z-lines and intercalated disks; IIB, increased desmin staining with irregular pattern of cross-striation and/or with presence of aggregates; and III, decreased or lack of desmin staining. Patients with type III had a greater New York Heart Association class and N-terminal pro-brain natriuretic peptide level, larger LV end-diastolic diameter, and lower LV ejection fraction than patients with type I (p <0.001). At the end of follow-up (mean duration 59 ± 33 months), 44 patients (22%) had died and 5 (2.5%) had undergone heart transplantation. Patients with type III had an increased risk of death or heart transplantation in univariate Cox proportional hazard regression models (adjusted hazard ratio 7.18, 95% confidence interval 2.96 to 17.40, p <0.001) and multivariate models (New York Heart Association class, LV end-diastolic diameter, LV ejection fraction, N-terminal pro-brain natriuretic peptide, gender, and age; hazard ratio 5.24, 95% confidence interval 1.58 to 17.38, p = 0.007). In conclusion, in patients with idiopathic dilated cardiomyopathy, a decrease or lack of desmin expression seems to be a strong, independent predictor of an unfavorable prognosis. Our outcomes support the relevance of exploring desmin expression as a potential target to treat heart failure progression.

Dopaminergic neuronal conversion from adult rat skeletal muscle-derived stem cells in vitro

Muscle-derived stem cells reside in the skeletal muscle tissues and are known for their multipotency to differentiate toward the mesodermal lineage. Recent studies have demonstrated their capacity of neuroectodermal differentiation, including neurons and astrocytes. In this study, we investigated the possibility of dopaminergic neuronal conversion from adult rat skeletal muscle-derived stem cells. Using a neurosphere protocol, muscle-derived stem cells form neurosphere-like cell clusters after cultivation as a suspension, displaying an obvious expression of nestin and a remarkable down-regulation of myogenic associated factors desmin, MyoD, Myf5 and myogenin. Subsequently, these neurosphere-like cell clusters were further directed to dopaminergic differentiation through two major induction steps, patterning to midbrain progenitors with sonic hedgehog and fibroblast growth factor 8, followed by the differentiation to dopaminergic neurons with neurotrophic factors (glial cell line-derived neurotrophic factor) and chemicals (ascorbic acid, forskolin). After the differentiation, these cells expressed tyrosine hydroxylase, dopamine transporter, dopamine D1 receptor and synapse-associated protein synapsin I. Several genes, Nurr1, Lmx1b, and En1, which are critically related with the development of dopaminergic neurons, were also significantly up-regulated. The present results indicate that adult skeletal muscle-derived stem cells could provide a promising cell source for autologous transplantation for neurodegenerative diseases in the future, especially the Parkinson's disease.

Vascular and mesenchymal factors during heart development: a chronological study

As heart development is an incomplete described area, and likewise an important source of intra- and post-partum morbidity and mortality, we have aimed at analyzing both vascular and cytoskeletal factors during early heart development in humans. The distribution of CD105, CD31, α-SMA, vimentin and desmin have been studied on a series of normal human heart tissues varying between five and 33 weeks of gestational age, utilizing both enzymatic single immunohistochemistry, as well as double immunofluorescence. We showed here that CD105 is already expressed at five weeks of gestational age in the future endocardium, and that between 9 and 10 weeks it shows clear-cut formed vessels. CD31 was also present diffusely at five weeks in the myocardium, while beginning with seven weeks, endocardium and vessels were clearly positive. Contrary to what it might be expected for striated muscle cells, cardiomyocytes were α-SMA positive between 9 and 20 weeks, a time window during which the marker showed clear-cut sarcomer formation. Desmin was first detected at nine weeks lining the cardiomyocyte plasma membrane, and after 17 weeks it showed the adult-like striated pattern of the protein. As expected, vimentin was already present in the mesenchymal cells from the first investigated time point, retaining a perivascular localization only towards higher ages. This is the first study that describes these vascular, muscular and mesenchymal factors on a large series of sequential human tissues, in an attempt to shed more light on the development of heart.

[Desmin content and cell breathing in rats' m. soleus fibers after 3- and 7-day recovery from 14-day suspension]

Cell breathing and relative desmin content were investigated in m. soleus fibers of rats after 3 and 7 days of recovery from 14-day suspension according to the Morey - Holton modification of the Ilyin - Novikov procedure. The cell breathing parameters were determined with the help of polarography; desmin content was measured using the western-blot technique. The results evidence that cell breathing intensity subsided during 14 days of gravitational unloading, reached minimum after 3 days of recovery and regained baseline values after 7 days of recovery. Post suspension desmin content did not differ from control values, made a significant drop in 3 days and returned to baseline values in 7 days of recovery. These data suggest an interdependence between cell breathing and desmin content in m. soleus fibers of rats as during gravitation unloading, so in the period of recovery.

Clinical and histopathological profile of primary or secondary osteosarcoma of the jaws

Osteosarcoma of the jaw is a rare disease; we report two cases, one in which the primary osteosarcoma had occurred in the sacrum and ileum, the second at the mandible. Dissemination of osteosarcoma to other organs, especially early dissemination to the lung, is common, but metastasis to the jaw has only rarely been reported. About 10% of osteosarcomas occur in the head and neck, most in the mandible or maxilla. Clinically, both patients presented swelling, and pain at the jaw in the premolar-molar region. At radiography, extensive bone erosion and soft-tissue swelling were apparent. A biopsy was taken and a diagnosis of osteosarcoma rendered in both cases. Histological examination revealed a proliferation of atypical osteoblast-like cells with hyperchromatic nuclei and formation of scattered neoplastic osteoid tissue. Immunohistochemistry for a panel of antibodies showed strong positivity for CD99, weak positivity for S-100, but was negative for desmin, vimentin, and cytokeratins. The diagnosis for both cases was of osteogenic osteosarcoma, chondroblastic subtype. Unfortunately, both patients died, one before the planned chemotherapy regime could begin, the second during the chemotherapy course. Our report aims to highlight the importance of the diagnostic profile in formulating a diagnosis of osteosarcoma, and that this tumor, although very rare, may be primary or may metastasize to the jaws.

A novel role of vimentin filaments: binding and stabilization of collagen mRNAs

The stem-loop in the 5' untranslated region (UTR) of collagen α1(I) and α2(I) mRNAs (5'SL) is the key element regulating their stability and translation. Stabilization of collagen mRNAs is the predominant mechanism for high collagen expression in fibrosis. LARP6 binds the 5'SL of α1(I) and α2(I) mRNAs with high affinity. Here, we report that vimentin filaments associate with collagen mRNAs in a 5'SL- and LARP6-dependent manner and stabilize collagen mRNAs. LARP6 interacts with vimentin filaments through its La domain and colocalizes with the filaments in vivo. Knockdown of LARP6 by small interfering RNA (siRNA) or mutation of the 5'SL abrogates the interaction of collagen mRNAs with vimentin filaments. Vimentin knockout fibroblasts produce reduced amounts of type I collagen due to decreased stability of collagen α1(I) and α2(I) mRNAs. Disruption of vimentin filaments using a drug or by expression of dominant-negative desmin reduces type I collagen expression, primarily due to decreased stability of collagen mRNAs. RNA fluorescence in situ hybridization (FISH) experiments show that collagen α1(I) and α2(I) mRNAs are associated with vimentin filaments in vivo. Thus, vimentin filaments may play a role in the development of tissue fibrosis by stabilizing collagen mRNAs. This finding will serve as a rationale for targeting vimentin in the development of novel antifibrotic therapies.

Biological and morphological characterization of in vitro expanded human muscle-derived stem cells

Stem cells are generally characterised as clonogenic and undifferentiated cells with the capacity of self-renewal and plasticity. Over the past few years, the adult stem cells have been derived from various types of tissues including the skeletal muscle. The main goal of the present study was the isolation, in vitro expansion and characterisation of muscle-derived stem cells (MDSCs). Thereby obtained results showed that MDSCs have a fibroblast-like shape with a large nucleus having one to four nucleoli. The cytoplasm was transparent without any signs of vacuolisation. TEM analysis showed an ultrastructure of cells with high proteosynthetic activity. MDSCs had a large and irregular nucleus with variable number of nucleoli. The cytoplasm contained a richly developed and rough endoplasmic reticulum, prominent Golgi apparatus cisterns as well as transport vesicles containing glycogen granules and variable microvilli and filopodia. They expressed alpha-actin and desmin. Results of the phenotypic characterization showed that the analyzed cells were positive for CD29, CD34, CD44, CD90, CD105 and HLA Class I. They did not express CD14, CD45, CD235a, HLA Class II and human fibroblast surface protein. According to these results it should be emphasised that MDSCs after performing the detailed studies focused on their immunological properties and differentiation potential may be used in the cell therapy of many degenerative diseases.

Effects of upregulated expression of microRNA-16 on biological properties of culture-activated hepatic stellate cells

In our previous studies, we identified miR-16 as being downregulated during activation of hepatic stellate cells (HSCs) by microarray hybridization. However, the roles and related mechanisms of miR-16 in HSCs are not understood. In this study, The miRNA RNAi technique was used to analyze the effects of miR-16 on biological properties of HSCs in vitro. The lentiviral vector encoding miR-16 was constructed and transfected. Furthermore, the expression level of miR-16 was measured by real-time PCR. Cellular growth and proliferation capacity were assayed using the cell counting kit-8 (CCK-8). The apoptosis rate and cell-cycle distribution were measured by flow cytometry. Cell morphological characteristics were identified by phase-contrast microscopy, fluorescence microscopy and electron microscopy. The underlying mechanisms related to the changes in biological properties were assessed. The identity of the recombinant plasmid was confirmed by restriction endonuclease analysis and DNA sequencing. Virus titer was 10(8) > ifu/m. Restoring the intracellular miRNAs by miR-16 administration greatly reduced the expression levels of cyclin D1 (CD1). Cell-cycle arrest and typical features of apoptosis were detected in activated HSCs treated with pLV-miR-16. Our results indicate that transduction of miR-16 offers a feasible approach to significantly inhibit HSC proliferation and increase the apoptosis index. Thus, targeted transfer of miR-16 into HSC may be useful for the treatment of hepatic fibrosis.

Bone marrow transplantation demonstrates medullar origin of CD34+ fibrocytes and ameliorates hepatic fibrosis in Abcb4-/- mice

Bone marrow (BM)-derived stem cells and CD34(+) fibrocytes are associated with fibrogenesis in several organs. In an Abcb4(-/-) mouse model for sclerosing cholangitis alpha-smooth muscle actin-positive (alpha-SMA(+)) myofibroblasts are thought to play a pivotal role in hepatic fibrogenesis. The aim of this study was 2-fold: (1) to demonstrate that the origin of an important fibrogenetic cell population is the BM; and (2) to investigate whether transplantation of BM (BM-Tx) affects liver function, staging, and grading. Surrogate markers for fibrogenesis and regulation of hepatic stellate cells (HSC) as well as progenitor-cell-derived fibrocytes in liver tissue were analyzed by quantitative real-time polymerase chain reaction (PCR) and immunohistology. After lethal irradiation of recipient mice, BM-Tx was carried out by way of tail vein injection of BM cells from marker protein donors (green fluorescent protein, GFP(+)) or Abcb4(-/-) mice as control (syngeneic Tx). Parameters of liver function were assessed serologically and histologically. Activated HSC of alpha-SMA(+)/CRP2(+) phenotype were expressed in approximately 50% of proliferating bile ducts, whereas fibrotic liver parenchyma showed no expression thereof. Epithelial mesenchymal transfer (EMT) was visualized in the areas of proliferating bile ducts. The hematopoietic origin of CD34(+) fibrocytes was demonstrated immunohistologically in livers of BM chimeric mice. These CD34(+) cells infiltrated hepatic lobules from portal fields and developed a desmin(+) phenotype expressing collagen type I in fibrotic parenchyma as well as in vitro after isolation by magnetic cell separation. Transplantation of GFP(+)/Abcb4(+) BM improved liver function and staging compared with sham transplantation, but no significant differences were noticed among allogeneic and syngeneic Tx.

CONCLUSION

The present study is the first to identify that both BM-derived fibrocytes and HSC are involved in biliary fibrogenesis in Abcb4(-/-) mice. Our data suggest that changes in immunity subsequent to BM-Tx may alter hepatic fibrosis.

[Effect of benazepril on atrial cytoskeleton remodeling in the canine atrial fibrillation models]

OBJECTIVE

To investigate the effect of benazepril on atrial cytoskeleton remodeling in atrial fibrillation (AF) canines induced by chronic rapid atrial pacing (RAP).

METHODS

Twenty canines were randomly divided into 3 groups: (1) Sham-operated group without RAP; (2) AF group: AF established by RAP at 600 beats per minute for 6 weeks; (3) Benazepril group: benazepril was dosed from 1 week pre-pacing to 6 weeks post-pacing. The diameter of atrial cardiomyocyte was measured, collagen volume fraction (CVF) analyzed by Masson staining and the expression and distribution of desmin were assayed by immunohistochemistry. RT-PCR method was used to semi-quantify the mRNA expression of beta-tubulin and desmin.

RESULTS

The diameter of atrial cardiomyocyte increased in AF group [LA:(27.9 +/- 3.8) microm; RA: (26.8 +/- 3.2) microm] and benazepril group[LA: (25.1 +/- 3.4) microm; RA: (25.2 +/- 3.5) microm] than sham-operated group [LA: (19.6 +/- 2.9) microm; RA: (18.7 +/- 2.6) microm] (P < 0.01). CVF increased in AF group than sham-operated group [LA: (16.9 +/- 1.1)% vs (9.2 +/- 0.9)%, RA: (15.7 +/- 2.3)% vs (9.3 +/- 0.8)%, P < 0.01] and it decreased in benazepril group than AF group [LA: (11.3 +/- 0.8)% vs (16.9 +/- 1.1)%, RA: (10.9 +/- 0.8)% vs (15.7 +/- 2.3)%, P < 0.01]. Normal desmin cross-striations were lost in atrial cardiomyocyte and the desmin organization became irregular in AF group. The A values analyzed by immunohistochemistry of desmin increased in AF group than sham-operated group and they decreased in benazepril group than AF group (P < 0.01). The expression of mRNA level of desmin and beta-tubulin were up-regulated in AF group than sham-operated group, (LA:1.0 +/- 0.3 vs 0.6 +/- 0.3, 0.9 +/- 0.4 vs 0.6 +/- 0.3; RA: 1.0 +/- 0.6 vs 0.6 +/- 0.2, 1.1 +/- 0.3 vs 0.7 +/- 0.4, P < 0.01) and they were down-regulated in benazepril group than AF group (LA:0.8 +/- 0.4 vs 1.0 +/- 0.3, 0.7 +/- 0.3 vs 0.9 +/- 0.4; RA:0.7 +/- 0.3 vs 1.0 +/- 0.6, 0.7 +/- 0.3 vs 1.1 +/- 0.3, P < 0.01).

CONCLUSION

Benazepril can favorably improve atrial cytoskeleton remodeling in the canine atrial fibrillation model.

[Protective effects of Shenkangwan against podocyte injury in rats with early diabetic nephropathy]

OBJECTIVE

To investigate the morphological changes and expressions of desmin and podocin in podocytes of rats with diabetic nephropathy (DN) rats and renal protection mechanism of Shenkangwan.

METHODS

DN model was established in rats by a single injection of streptozotocin. The rats were then randomly divided into model group, Shenkangwan treatment group, irbesartan treatment group, and Shenkangwan plus irbesartan treatment group, with normal rats as the control group. All the rats received daily gavage for 8 weeks. The urinary protein quantity in 24 h were detected, and the morphological changes of the kidneys were observed with optic and transmission electron microscopes. The expressions of desmin and podocin in the podocytes were detected by immunohistochemistry.

RESULTS

Shenkangwan and irbesartan reduced the urinary protein quantity in 24 h and alleviated the renal damage in DN rats, and the expression of desmin was significantly attenuated while podocin expression increased in the podocytes.

CONCLUSIONS

Shenkangwan can provide renal protection against DN in rats and alleviate the structural and functional damages of podocytes possibly by reducing desmin expression and increasing podocin expression in the podocytes.

[Expression of CD117, CD34, SMA, S-100 protein, Vim and desmin in patients with gastrointestinal stromal tumors]

OBJECTIVE

To investigate the clinicopathological diagnosis and expressions of CD117, CD34, SMA, S-100 protein, Vimentin(Vim) and desmin in gastrointestinal stromal tumors (GISTs).

METHODS

A retrospective analysis of the clinical data and the results of various examinations was conducted among 35 patients with pathologically confirmed GISTs undergoing surgical resection. The expressions of CD117, CD34, SMA, S-100, Vim and desmin in the tumor tissues were detected by immunohistochemistry with SP method.

RESULTS

In these GIST cases, the tumors were located mostly in the stomach (n=11), small intestines (n=11), and abdominal cavity (n=5). The main clinical manifestations included abdominal distension, abdominal pain, gastrointestinal bleeding, and abdominal masses. The positivity rates of CD117 and CD34 in the tumors were 94.3% and 91.4%, respectively, both significantly higher than those of SMA, S-100, Vim and Desmin (P<0.001), and also higher than that in leiomyoma (P<0.0001). The positivity rate of Desmin was only 2.9% in the tumors, significantly lower than those of CD117 and CD34 (P<0.05) and that in liomyoma (P<0.001).

CONCLUSIONS

GISTs occur mostly in the stomach and small intestines, and endoscopy, ultrasound endoscope and CT examination are effective modalities for diagnosis of GISTs. A definite diagnosis of GISTs can be established in the presence of positive expression of CD117 and CD34 and negative expression of Desmin in the tumor.

[Specific features of satellite cells and myoblasts at different stages of rat postnatal development]

A cell culture consisting mainly of satellite cells and mononuclear myoblasts was derived from femoral muscles of infant (aged 3-7 days) and adult rats. Satellite cells identified by expression of the specific marker Pax7 accounted for approximately 80% of the isolated cell fraction. Mononuclear myoblasts represented by proliferating and postmitotic cell pools were identified immunocytochemically by the expression of markers Ki67 and desmin. Differentiation of satellite cells and myoblasts in the culture depended on the concentration of Ca2+ in the culture medium (F12 with different Ca2+ concentrations or DMEM). Differentiation of myogenic cells manifested in myoblasts fusion, formation of myotubes, and expression of myosin in myofibrils was observed only in the medium with a high Ca2+ concentration (2 mM). Satellite cells and myoblasts from the muscles of newborn and adult rats did not differ noticeably in their capacity for differentiation.

Effects of inhibitors of the arachidonic acid cascade on primary muscle culture from a Duchenne muscular dystrophy patient

The aim of this study was to elucidate the mechanisms of action for potential targets of therapeutic intervention related to the arachidonic acid cascade in muscular dystrophy. Primary cultures from a Duchenne patient were used to study the expression of dystrophin-1, utrophin, desmin, neonatal myosin heavy chain (MHCn) and Bcl-2 during inhibition of phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX). Hypo-osmotic treatment was applied in order to trigger Ca2+ influx and PLA2 activity. Inhibition of PLA2 and LOX with prednisolone and nordihydroguaiaretic acid (NDGA) caused a semi-quantitative increase of utrophin and Bcl-2-, and a dose-dependent, quantitative increase of desmin expression, an effect that was augmented by hypo-osmotic treatment. Our results indicate that LOX inhibitors, similarly to corticosteroids, can be beneficial in the treatment of muscular dystrophies.

Desmin stimulates differentiation of cardiomyocytes and up-regulation of brachyury and nkx2.5

Desmin contributes to structural integrity and function of the myocardium but its function seems to be redundant in early cardiomyogenesis in the desmin null mouse model. To test the hypothesis that desmin also plays a supportive role in cardiomyogenic commitment and early differentiation of cardiomyocytes we investigated cardiomyogenesis in embryoid bodies expressing different desmin alleles. Constitutive expression of desmin and increased synthesis during mesoderm formation led to the up-regulation of brachyury and nkx2.5 genes, accelerated early cardiomyogenesis and resulted in the development of large, proliferating, highly interconnected, and synchronously beating cardiomyocyte clusters, whereas desmin null cardiomyocytes featured an opposite phenotype. In contrast, constitutive expression of amino-terminally truncated desmin(Delta1-48) interfered with the beginning of cardiomyogenesis, caused down-regulation of mesodermal and myocardial transcription factors, and hampered myofibrillogenesis and survival of cardiomyocytes. These results provide first evidence that a type III intermediate filament protein takes part in regulating the differentiation of mesoderm to cardiomyocytes at the very beginning of cardiomyogenesis.

Prevalence of Desmin Mutations in Dilated Cardiomyopathy

BACKGROUND

Desmin-related myofibrillar myopathy (DRM) is a cardiac and skeletal muscle disease caused by mutations in the desmin (DES) gene. Mutations in the central 2B domain of DES cause skeletal muscle disease that typically precedes cardiac involvement. However, the prevalence of DES mutations in dilated cardiomyopathy (DCM) without skeletal muscle disease is not known.

METHODS AND RESULTS

Denaturing high-performance liquid chromatography was used to screen DES for mutations in 116 DCM families from the Familial Dilated Cardiomyopathy Registry and in 309 subjects with DCM from the Beta-Blocker Evaluation of Survival Trial (BEST). DES mutations were transfected into SW13 and human smooth muscle cells and neonatal rat cardiac myocytes, and the effects on cytoskeletal desmin network architecture were analyzed with confocal microscopy. Five novel missense DES mutations, including the first localized to the highly conserved 1A domain, were detected in 6 subjects (1.4%). Transfection of DES mutations in the 2B domain severely disrupted the fine intracytoplasmic staining of desmin, causing clumping of the desmin protein. A tail domain mutation (Val459Ile) showed milder effects on desmin cytoplasmic network formation and appears to be a low-penetrant mutation restricted to black subjects.

CONCLUSIONS

The prevalence of DES mutations in DCM is between 1% and 2%, and mutations in the 1A helical domain, as well as the 2B rod domain, are capable of causing a DCM phenotype. The lack of severe disruption of cytoskeletal desmin network formation seen with mutations in the 1A and tail domains suggests that dysfunction of seemingly intact desmin networks is sufficient to cause DCM.

Thalidomide prevents rat liver cirrhosis via inhibition of oxidative stress

This study investigated the effect of thalidomide on oxidative stress in rat liver cirrhosis. The cirrhosis of rat was induced by intraperitoneal injection of carbon tetrachloride thrice weekly; meanwhile, thalidomide (10mg/kg or 100mg/kg) was given daily by intragastric administration for 8 weeks. The content of oxidative stress parameters, including superoxide dismutase, glutathione peroxidase, and malondialdehyde, in the liver was detected by biochemical assay. Immunohistochemistry revealed alpha-smooth muscle actin (alpha-SMA), desmin, and tissue inhibitor of metalloproteinase-1 (TIMP-1) protein in the liver. Nuclear factor kappa B p65 (NF-kappaBp65) protein in nucleus and transforming growth factor beta1 (TGF-beta1) protein in cytoplasm were detected by Western blot. NF-kappaBp65, TGF-beta1, and TIMP-1 mRNA levels in the liver were studied using reverse transcriptase polymerase chain reaction. Liver histopathology was significantly improved in rats given high doses of thalidomide. The content of oxidative stress parameters and the expressions of NF-kappaBp65, TGF-beta1 and TIMP-1 protein, and mRNA were significantly decreased in these animals. The expressions of alpha-SMA and Desmin protein were also significantly decreased in them. Thalidomide might exert an effect on the inhibition of oxidative stress via downregulation of NF-kappaB signaling pathway to prevent the progression of liver cirrhosis.

[Correlation between desmin gene, platelet-activating factor acetylhydrolase gene and dilated cardiomyopathy]

OBJECTIVE

To test the Missense mutation of Desmin gene (Ile451Met), the frequency of missense mutation (G994-->T) of Platelet-Activating Factor Acetylhydrolase (PAF-AH) gene, and the correlation between these mutations and dilated cardiomyopathy (DCM) in the Chinese population with DCM.

METHODS

A case control study was conducted with 89 DCM patients and 110 healthy people (control group) participating in the study. The exon 8 of Desmin gene and exon 9 of PAF-AH gene were identified by polymerase chain reaction, restriction enzyme digestion, polyacrylamide gel electrophoresis and DNA sequencing for described mutation site of Desmin (Ile451Met) and PAF-AH (Val279Phe).

RESULTS

No mutation (Ile451Met) in Desmin gene was found in either the DCM patients or the healthy people. There was no significant difference in the frequency of PAF-AH gene mutation (Val279Phe) between the patient and control groups (P>0.05).

CONCLUSION

Neither the mutation of Ile451Met in gene encoding for Desmin exon 8 nor the mutation frequency of PAF-AH gene (G994-->T) has correlation with the DCM.

Treatment with 1,25-dihydroxyvitamin D3 preserves glomerular slit diaphragm-associated protein expression in experimental glomerulonephritis

In this study, we investigated the effect of 1,25(OH)2D3 on proteinuria and on the alteration of slit diaphragm-associated proteins induced by anti-Thy 1.1 in Wistar rats. Four groups of animals were studied: group I, anti-Thy 1.1 treated rats; group II, anti-Thy1.1 treated group that at day 2, after the onset of overt proteinuria, started the treatment with 1,25(OH)2D3; group III, normal control rats injected with vehicle alone; group IV, rats that received only 1,25(OH)2D3. At day 2, in group I and II, before the administration of 1,25(OH)2D3, protein excretion was significantly increased when compared to controls. Overt proteinuria was maintained until day 14 in group I whereas in group II protein excretion was significantly reduced from day 3 to day 14. Moreover, treatment with 1,25(OH)2D3 abrogated podocytes injury, detected as desmin expression and loss of nephrin and zonula occludens-1 (ZO-1), two slit diaphragm-associated proteins, and glomerular polyanion staining, that were observed in group I. In conclusion, these results suggest that 1,25(OH)2D3 administrated with a therapeutic regiment may revert proteinuria, counteracting glomerular podocyte injury.

ACE inhibitors improve nephrin expression in Zucker rats with glomerulosclerosis

BACKGROUND

Podocyte injury is associated with many forms of human and experimental proteinuric glomerular disease. The aim of this study was to investigate the level of nephrin expression in a model of obesity and type II diabetes mellitus, the obese Zucker rat, as well as to investigate whether nephrin expression is influenced by treatment with quinapril or diltiazem, 2 drugs frequently used in type II diabetes mellitus.

METHODS

Obese Zucker rats were treated with either quinapril or diltiazem at a dose of 10 mg/kg body weight per day and 100 mg/kg body weight per day, respectively, for 6 months. Real time reverse transcription-polymerase chain reaction (RT-PCR) and immunoperoxidase assays were used to assess and quantify nephrin gene expression and other markers of podocyte damage, such as desmin and synaptopodin protein.

RESULTS

Quinapril treatment prevented the reduction of nephrin levels compared with the control group, while diltiazem treatment did not prevent the reduction. Similar results were obtained when other phenotypic markers, such as desmin, were assessed. Similarly, synaptodin showed this tendency, although it did not achieve statistically significant differences.

CONCLUSION

The podocyte phenotypic changes assessed in a model of obesity and type II diabetes mellitus were corrected by an angiotensin-converting enzyme (ACE) inhibitor. These results could be associated with an improvement in the slit diaphragm, and therefore, in the maintenance of the filtration barrier. Diltiazem did not achieve similar results.

Temporal and spatial variations in structural protein expression during the progression from stunned to hibernating myocardium

BACKGROUND

Dysfunctional and normally perfused remote regions show equal myolysis and glycogen accumulation in pig hibernating myocardium. We tested the hypothesis that these arose secondary to elevations in preload rather than ischemia.

METHODS AND RESULTS

Expression of structural protein (desmin, desmoplakin, titin, cardiotin, alpha-smooth muscle actin, lamin-A/C, and lamin-B2) in viable dysfunctional myocardium was analyzed by immunohistochemistry. We performed blinded analysis of paired dysfunctional left anterior descending coronary artery and normal remote subendocardial samples from stunned (24 hours; n=6), and hibernating (2 weeks; n=6) myocardium versus sham controls pigs (n=7). Within 24 hours, cardiac myocytes globally reexpressed alpha-smooth muscle actin. In stunned myocardium, cardiotin was globally reduced, whereas reductions in desmin were restricted to the dysfunctional region. Alterations progressed with the transition to hibernating myocardium, in which desmin, cardiotin, and titin were globally reduced. A qualitatively similar reorganization of cytoskeletal proteins occurred 3 hours after transient elevation of left ventricular end-diastolic pressure to 33+/-3 mm Hg.

CONCLUSIONS

Qualitative cardiomyocyte remodeling similar to that in humans with chronic hibernation occurs rapidly after a critical coronary stenosis is applied, as well as after transient elevations in left ventricular end-diastolic pressure in the absence of ischemia. Thus, reorganization of cytoskeletal proteins in patients with viable dysfunctional myocardium appears to reflect chronic and/or cyclical elevations in preload associated with episodes of spontaneous regional ischemia.

Expression of endothelial nitric oxide synthase in the vascular wall during arteriogenesis

Nitric oxide (NO) has been demonstrated to play an important role in angiogenesis, and also to be involved in collateral vessel growth. The expression of endothelial NO synthase (eNOS) is moderated partly by blood flow-induced mechanical factors, i.e., shear stress. The purpose of this study was to evaluate how the expression of eNOS correlates with the development of collateral vessels in dog heart, induced by chronic occlusion of the left circumflex artery. Immunoconfocal microscopy using an antibody against eNOS was used to detect expression of eNOS in different stages of arteriogenesis. Collateral vessels were classified into normal, growing and mature vessels by using the cytoskeleton marker desmin. Expression of the growth factors bFGF and metallproteinase-2 (MMP-2) was also examined. The data show that in normal arteriolar vessels, expression of eNOS is very low, but in growing collateral vessel there is a 6.2-fold increase, which, however, returned to normal levels in mature collateral vessels. The expression of eNOS was localized only in endothelium, either in normal or growing vessels. bFGF was very weakly stained in normal vessels, but highly expressed in growing collateral vessels. MMP-2 was strongly stained in neointima, but very weak in endothelium. In addition, we also examined expression of iNOS because iNOS may be induced in vessel injury or in disease states, but it was not detected in either normal or growing collateral vessels. Our findings indicate that the expression pattern of eNOS is closely associated with the development of collateral vessels, suggesting that eNOS plays an important role in arteriogenesis.

Relationship between major and minor salivary gland mucoepidermoid carcinoma malignancy grading and presence of stromal myofibroblasts: immunohistochemical study

OBJECTIVE

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary tumour, classified as low, intermediate and high grade. Myofibroblasts are the main stromal component and are included as prognostic factor in some tumours. The aim of this study was to evaluate the myofibroblasts in the stroma of MEC with possible relationship to malignancy grading.

METHODS

Twenty-five cases of MEC (six low grade, 11 intermediate grade, four high grade and four metastasis) were stained for vimentin, desmin and smooth muscle actin (SMA) for the identification of myofibroblasts. Transforming growth factors (TGFbeta1 and TGFbetaRII) were also assessed in our study.

RESULTS

Myofibroblasts were present in all cases, in amounts varying according to histological grading. TGFbeta1 was positive in squamous cells of intermediate grade tumours, and in the stroma of only four cases. TGFbetaRII was positive in most squamous and intermediate cells, regardless of malignancy grading.

CONCLUSIONS

Our study showed that the analysis of neoplastic stroma must be added to the studies of neoplastic cells to draw a better picture leading to tumour diagnosis and prognosis.

Desmin-positive pericytes in the chick embryo chorioallantoic membrane in response to fibroblast growth factor-2

Pericytes stabilize vessel wall, participate in the regulation of blood flow microcirculation and influence endothelial proliferation, survival, migration and maturation. Pericytes are commonly identified by molecular markers, such as desmin. The aim of this study was to analyze the pattern of distribution of desmin in the chick embryo chorioallantoic membrane (CAM) vasculature in normal condition and in response to an angiogenic cytokine, such as fibroblast growth factor-2 (FGF-2) by using conventional immunohistochemistry and confocal laser scanning microscopy. Results indicate that, in normal condition, the desmin-positive pericytes are located around the endothelial cells of the capillary plexus and of larger vessels in the intermediate mesenchyme. In response to FGF-2 numerous desmin-positive and alpha smooth muscle actin-negative cells are located in the mesenchyme and numerous blood vessels positive to factor VIII and desmin are recognizable near to the gelatin sponge soaked with FGF-2. These data suggest that pericytes in normal condition intervene to stabilize the wall of newly formed blood vessel, while in response to FGF-2, they detach from the wall of parental vessels and migrate, as extramural fibroblast-like desmin-positive cells, in the surrounding mesenchyme, where they modulate the angiogenic response.

Isolation and enrichment of skeletal muscle progenitor cells from mouse bone marrow

There is great interest in the therapeutic potential of non-hematopoietic stem cells obtained from bone marrow called mesenchymal stem cells (MSCs). Rare myogenic progenitor cells in MSC cultures have been shown to convert into skeletal muscle cells in vitro and also in vivo after transplantation of bone marrow into mice. To be clinically useful, however, isolation and expansion of myogenic progenitor cells is important to improve the efficacy of cell transplantation in generating normal skeletal muscle cells. We introduced into MSCs obtained from mouse bone marrow, a plasmid vector in which an antibiotic (Zeocin) resistance gene is driven by MyoD and Myf5 enhancer elements, which are selectively active in skeletal muscle progenitor cells. Myogenic precursor cells were then isolated by antibiotic selection, expanded in culture, and shown to differentiate appropriately into multinucleate myotubes in vitro. Our results show that using a genetic selection strategy, an enriched population of myogenic progenitor cells, which will be useful for cell transplantation therapies, can be isolated from MSCs.

Modulation of phenotype of human prostatic stromal cells by transforming growth factor-betas

BACKGROUND

We investigated the effects of transforming growth factor (TGF)-betas on morphological and receptor phenotypes, as well as proliferation of four currently established human prostatic myofibroblast cell lines and one commercially available prostatic stromal cell line.

METHODS

The effects of TGF-betas on morphological changes and proliferation of the cells were studied by immunohistochemistry and bromodeoxyuridine assay, respectively. The expression of alpha 1-receptor subtypes was measured by real time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and the radioligand binding assay for the receptors was also performed.

RESULTS

TGF-betas 1, 2, and 3 induced expression of desmin and myosin of cells of the established cell lines, and significantly inhibited their growth. The alpha 1a-receptor was expressed only in the commercially available cell line and alpha 1b and 1d, in all cell lines. TGF-beta 1 suppressed the expression of all three subtypes of the alpha 1-receptor. The binding sites of cells of all the cell lines were reduced by treatment with this growth factor.

CONCLUSIONS

TGF-betas may induce human prostatic stromal cells to express the smooth muscle phenotype and inhibited their growth. However, the growth factor reduced the binding sites of the receptor and suppressed mRNA expression of its subtypes, suggesting that morphological and receptor phenotypes may be regulated via more than one pathway by TGF-beta(s).

Phosphorylation of MRF4 transactivation domain by p38 mediates repression of specific myogenic genes

Skeletal myogenesis is associated with the activation of four muscle regulatory factors (MRFs): Myf5, MyoD, Myogenin and MRF4. Here we report that p38 mitogen-activated protein kinase represses the transcriptional activity of MRF4 (involved in late stages of myogenesis), resulting in downregulation of specific muscle genes. MRF4 is phosphorylated in vitro and in vivo by p38 on two serines (Ser31 and Ser42) located in the N-terminal transactivation domain, resulting in reduced MRF4-mediated transcriptional activity. In contrast, nonphosphorylatable MRF4 mutants display increased transcriptional activity and are able to advance both myoblast fusion and differentiation. We also show that expression of desmin and alpha-actin, but not muscle creatin kinase, decreased at late stages of muscle differentiation, correlating with the induction of MRF4 and p38 activation. Accordingly, inhibition of p38 during late myogenesis results in the upregulation of both desmin and alpha-actin. We propose that repression of MRF4 activity by p38 phosphorylation may represent a new mechanism for the silencing of specific muscle genes at the terminal stages of muscle differentiation.

Patterns of spatial and temporal visceral arch muscle development in the Mexican axolotl (Ambystoma mexicanum)

Vertebrate head development is a classical topic that has received renewed attention during the last decade. Most reports use one of a few model organisms (chicken, mouse, zebrafish) and have focused on molecular mechanisms and the role of the neural crest, while cranial muscle development has received less attention. Here we describe cranial muscle differentiation and morphogenesis in the Mexican axolotl, Ambystoma mexicanum. To determine the onset of differentiation we use antibodies against desmin and optical sectioning using confocal laser scanning microscopy on whole-mount immunostained embryos. This technique makes it possible to document the cranial muscle in three dimensions while keeping the specimens intact. Desmin expression starts almost simultaneously in the first, second, and third visceral arch muscles (as in other amphibians studied). Muscle anlagen divide up early into the different elements which constitute the larval cranial musculature. We extend and refine earlier findings, e.g., by documenting a clear division between interhyoideus and interhyoideus posterior. The timing of cranial muscle differentiation differs among vertebrate groups, but seems to be constant within each group. This study provides a morphological foundation for further studies of muscle cell fate and early differentiation.

Immunohistochemical markers in differential diagnosis of endometrial stromal sarcoma and cellular leiomyoma

OBJECTIVE

Distinction of endometrial stromal sarcoma (ESS) from benign smooth muscle proliferations like cellular leiomyoma (CL) is sometimes problematic. The purpose of this study was to evaluate the potential utility of a panel of antibodies in the differential diagnosis of ESS and CL.

METHODS

Using a standard streptavidin-biotin method, the expression of desmin, alpha smooth muscle actin (SMA), calponin h1, h-caldesmon, estrogen receptor (ER), progesterone receptor (PR), CD10, CD44v3, proliferating cell nuclear antigen (PCNA), and mast cells (MCs) were evaluated in 26 cases of ESS (21 low grade, 5 high grade), 25 CL (17 common CL, 8 highly CL), 25 myometria, and 25 endometria.

RESULTS

Among ESS, 20 of 26, 17 of 26, 9 of 26, 12 of 26, 14 of 26, and 22 of 26 were positive for expression of desmin, SMA, calponin h1, ER, PR, and CD10, respectively, while only 2 of 26 were positive for CD44v3 and all were entirely negative for h-caldesmon. Of CL, all were positive for SMA, calponin h1, PR, and CD44v3; 24 of 25, 24 of 25, and 19 of 25 were positive for desmin, h-caldesmon, and ER, respectively, whereas 1 of 25 focally marked with antibodies to CD10. There was no significant difference of PCNA expression between ESS and CL, although the ESS cases tended to have higher values. The MC counts were significantly higher in the CL group than in the ESS group (P < 0.01). When using the cut-off value of seven MCs per HPF to distinguish ESSs from CLs, the sensitivity and specificity of this cut-off value were 92.9% and 100%, respectively.

CONCLUSIONS

A panel of h-caldesmon, CD10, and CD44v3 should be used and will distinguish ESS from CL in most cases. In addition, counting the number of MCs might be useful as part of a multivariate approach to the differential diagnosis of them. But the biological function of MC and CD44v3 in these tumors is worthy of further investigation.

[Giant leiomyoma of the ovary]

Most of benign and malignant mesenchimal tumors may develop in the ovary. A case of 58 years old female, operated for ovary tumor is presented. A large soft mase 10-7-5 cm with in semilucent capsule is resected. Different (small and large) nodules with in edematous stroma constitute the tumor and imitate a large ovarian cancer. After histologic examination the nodules are composed of criss-crossing and whirling bundles of smooth muscle cells. Immunohistochemically they express Desmin diffusely and don't express Vimentin and S100 protein. Smooth muscle cells bundles in large amount of edematous, colagenous stroma look like islands. Stromal cells are Vimentin positive. Operation in this case is just limited to the tumor.

VEGF coordinates interaction of pericytes and endothelial cells during vasculogenesis and experimental angiogenesis

Biological activities of vascular endothelial growth factor (VEGF) have been studied extensively in endothelial cells (ECs), but few data are available regarding its effects on pericytes. In murine embryoid body cultures, VEGF-induced expression of desmin and alpha-smooth muscle actin (alpha-SMA) in CD-31+ cells. The number of CD-31+/desmin+ vascular chords increased with VEGF treatment time and peaked during a differentiation window between 6 and 9 days after plating. In vivo, VEGF-induced elongation and migration of desmin-positive pericytes and coverage of angiogenic capillaries, as revealed by analysis of Sambucus nigra lectin-stained vascular beds of the chick chorioallantoic membrane. VEGF also caused significant decrease of intercapillary spaces, an indicator for intussusceptive vascular growth. These VEGF-mediated effects point at a more intricate interaction between ECs and pericytes cells than previously demonstrated and suggest that pericytes may be derived from EC progenitors in vitro and not only stabilize capillaries but also participate in vascular remodeling in vivo.

Inclusion formation in Huntington's disease R6/2 mouse muscle cultures

Huntington's disease (HD) is an autosomal dominant disorder caused by an expansion in the number of glutamine repeats in the N-terminal region of the huntingtin protein. Nuclear and cytoplasmic aggregates of the N-terminal portion of huntingtin have been found in the brains of HD patients and the brains and non-neuronal tissues of the R6/2 HD transgenic mouse. We have cultured myoblasts and myotubes from transgenic R6/2 mice and littermate controls to investigate the formation of these inclusions in post mitotic cells. Huntingtin immunoreactivity was intense in differentiating, desmin positive myoblasts and myotubes from both control and R6/2 mice suggesting that it may play a role in myotube differentiation. Following differentiation huntingtin and ubiquitin positive aggregates were observed in R6/2 but not control cultures. After 3 weeks in differentiation medium cytoplasmic huntingtin and ubiquitin immunoreactive aggregates were observed in non-myotube cells, while nuclear huntingtin aggregates were seen in a proportion of myotubes after 6 weeks. Growth in the absence of serum resulted in a marked increase in the number of R6/2 myotubes containing nuclear inclusions after 6 weeks demonstrating that environmental factors influenced huntingtin aggregate formation in these cells. Consequently, cultured myotubes from R6/2 mice may be a useful post mitotic cell culture model to study both the biochemical consequences of huntingtin aggregates and the factors that may influence aggregate formation.

Primary intraosseous malignant fibrous histiocytoma of the skull: a case report

Malignant fibrous histiocytoma (MFH) is a rare primary neoplasm that constitutes less than 1% of the malignant tumors of bone, and involvement of the skull is very rare. We present a case of malignant fibrous histiocytoma of the skull, presenting an intraosseous lesion in a 43-yr-old woman. She had a rapidly growing, tender mass in the right parietal region. A plain radiograph showed an osteolytic lesion of the right parietal bone. Magnetic resonance imaging revealed that the lesion showed heterogeneous low signal intensity on T1-weighted images and slightly high signal intensity on T2-weighted images. No evidence of an extraosseous extension to the adjacent dura and soft tissue was found, and a wide excision of the parietal bone was performed. Histologically, the tumor was a typical MFH displaying pleomorphic spindle cells in a storiform pattern. The results of immunohistochemical stainings revealed that the tumor cells were positive for vimentin, alpha-1-antitrypsin, and p53, and negative for smooth muscle actin, S100 protein, desmin, and MyoD1. Three months later, a mainly cystic, recurrent mass was developed at the previously operated site. Before the resection, we first performed the percutaneous aspiration cytology, revealing diagnostic multinucleated pleomorphic cells. Thereafter, she had to receive repetitive resections of recurrent or residual lesions, and she died of postoperative meningoencephalitis two years after the first operation.

Myogenic and nonmyogenic cells differentially express proteinases, Hsc/Hsp70, and BAG-1 during skeletal muscle regeneration

Skeletal muscle has a remarkable capacity to regenerate after injury. To determine whether changes in the expression of proteinases, 73-kDa constitutive heat shock cognate protein (Hsc70) and stress-inducible 72-kDa heat shock protein (Hsp70) (Hsc/Hsp70), and Bcl-2-associated gene product-1 (BAG-1) contribute to the remodeling response of muscle tissue, tibialis anterior muscles of male Sprague-Dawley rats were injected with 0.75% bupivacaine and removed at 3, 5, 7, 10, 14, 21, or 35 days postinjection (n = 5-7/group). The immunohistochemical analysis of desmin, alpha-actin, and developmental/neonatal myosin heavy chain expressions indicated the presence of myoblasts (days 3-7), inflammatory cells (days 3-7), degenerating myofibers (days 3-7), regenerating myofibers (days 5-10), and growing mature myofibers (days 10-21) in regenerating muscles. Our biochemical analysis documented profound adaptations in proteolytic metabolism characterized by significant increases in the enzyme activities of matrix metalloproteinases 2 and 9 and plasminogen activators (days 3-14), calpains 1 and 2 (days 3-7), cathepsins B and L(days 3-10), and proteasome (days 3-14). Proteasome activity was strongly correlated with proliferating cell nuclear antigen protein level, suggesting that proteasome played a key role in myoblast proliferation. The expression pattern of BAG-1, a regulatory cofactor of Hsc/Hsp70 at the interface between protein folding and proteasomal proteolysis, did not corroborate the changes in proteasome enzyme activity, suggesting that BAG-1 may promote other functions, such as the folding capacity of Hsc/Hsp70. Altogether, the diversity of functions attributed to proteinases in the present study was strongly supported by the relative changes in the proportion of myogenic and nonmyogenic cells over the time course of regeneration.

Osteopontin expression in uterine stroma indicates a decidualization-like differentiation during ovine pregnancy

Osteopontin (OPN) is a component of the extracellular matrix that interacts with cell surface receptors, including integrins, to mediate cell adhesion, migration, differentiation, survival, and immune function. In pregnant mice and primates, OPN has been detected in decidualized stroma and is considered to be a gene marker for decidualization. Decidualization involves transformation of spindle-like fibroblasts into polygonal epithelial-like cells that are hypothesized to limit conceptus trophoblast invasion through the uterine wall during invasive implantation. Decidualization is not considered characteristic of species with noninvasive implantation, such as domestic animals. However, the extent of trophoblast invasion between sheep and pigs differs, with sheep exhibiting erosion of the uterine luminal epithelium (LE) and fusion of trophectoderm with LE to form syncytia, and pigs maintaining an intact LE throughout pregnancy. Therefore, the present study measured changes in the decidualization marker genes OPN, desmin, and alpha smooth muscle actin (alphaSMA) in ovine and porcine uterine stroma throughout pregnancy. The morphology of endometrial stromal cells in pregnant ewes changes following conceptus attachment, with cells increasing in size and becoming polyhedral in shape by Day 35 of pregnancy. Expression of OPN mRNA and protein, as well as desmin and alphaSMA proteins, was observed in this same uterine stromal compartment. In contrast, no morphological changes in uterine stroma nor induction of OPN mRNA and protein, or desmin protein, were detected during porcine pregnancy. Interestingly, alphaSMA protein was absent on Day 20, but prominent in uterine stroma of pregnant pigs on Day 45. Collectively, these results indicate that the uterine stroma of sheep undergoes a program of differentiation similar to decidualization in invasive implanting species, whereas porcine stroma exhibits differentiation that is more limited than that in sheep, rodents, or primates. Results suggest that uterine stromal decidualization is common to species with different types of placentation, but the extent is variable and correlates with the depth of trophoblast invasion during implantation.

Pulmonary lymphangioleiomyomatosis: a case report with immunohistochemical details and DNA analysis

A 47-year-old woman is presented with pulmonary lymphangioleiomyomatosis (PLAM) involving the bilateral lung and slight pulmonary function abnormality. Computed tomography scan showed bilateral microcyst formation in the lung. Histologically, proliferating spindle shaped cells with centrilobular emphysema were main findings. Immunohistochemically, these proliferating spindle shaped cells were positive for alpha-smooth muscle actin, desmin, vimentin, HMB45, estrogen receptor and progesterone receptor, but negative for S-100, cytokeratin. Single strand conformation polymorphism (SSCP) and DNA analysis for tuberous sclerosis 1 and 2 showed no significant abnormality.

The expression of cytoskeletal proteins (alpha-SMA, vimentin, desmin) in kidney tissue: a comparison of fetal, normal kidneys, and glomerulonephritis

BACKGROUND

The aim of the study is a comparison of the expression of cytoskeletal proteins, alpha smooth muscle actin (alpha-SMA), vimentin, and desmin in fetal, normal kidney and proliferative (diffuse proliferative and membranoproliferative glomerulonephritis) and nonproliferative (membranous glomerulonephritis) glomerulonephritis.

METHODS

We have studied the expression of cytoskeletal proteins (alpha-SMA, vimentin, desmin) in the paraffin embedded tissue sections from the kidneys of 10 normal kidney (adults and infants), 13 fetal kidney, 12 membranous glomerulonephritis (MGN), 8 membranoproliferative glomerulonephritis (MPGN), 8 diffuse proliferative glomerulonephritis (DPGN). Interstitial and glomerular positive stainings were evaluated.

RESULTS

Vimentin expression was similar in normal infant and adult kidneys with positive staining in glomeruli and negative staining in interstitium. In fetal kidneys, glomerular mesangial and epithelial cells and blastematous areas showed positive reactivity with vimentin. Alpha-SMA staining was different among the groups. In fetal kidney, alpha-SMA expression was found in glomerular mesangial cells and blastematous areas. Alpha-SMA staining was positive in peritubular area and glomerular mesangial cells in infant kidney. In adult kidneys, glomerular staining with alpha-SMA disappeared but peritubular positivity continued. Interstitial staining with alpha-SMA was positive in fibrotic areas of proliferative (MPGN, DPGN) and non-proliferative (MGN) glomerulonephritis, but positive glomerular staining with alpha-SMA was found only proliferative glomerulonephritis. Desmin expression was negative in all groups.

CONCLUSIONS

Desmin is not expressed in early stages of kidney growth, infant and adult kidneys, and proliferative and nonproliferative glomerulonephritis. Interstitial staining of vimentin in the diseased kidney tissues revealed increased fibrosis. Alpha-SMA revealed important differences in different stages of nephrogenesis. Glomerular mesangial staining with alpha-SMA in developing (fetal and infant kidneys) and proliferative glomerulonephritis suggest that it may be a marker of proliferation. In addition, it shows myofibroblastic differentiation in interstitium in diseased kidneys.

Ovarian teratomas with florid benign vascular proliferation: a distinctive finding associated with the neural component of teratomas that may be confused with a vascular neoplasm

Prominent benign vascular proliferations associated with neural tissue in five cases of ovarian teratoma are described. The ages of the patients ranged from 15 to 35 years. Three of the five had tumors confined to the ovary, one had peritoneal implants, and one had widespread metastatic immature teratoma. Two of the patients are alive and well, 8 and 9 years postoperatively. Follow-up is unavailable in two cases and the final case was recent. The tumor in three of the cases had features of mature cystic teratoma including abundant mature neural tissue and, in one instance, microscopic foci of primitive neuroepithelium. The tumor in the fourth case was an immature teratoma with abundant primitive neuroepithelium, and in the fifth case was a mixed germ cell tumor, composed mostly of immature teratoma with a minor component of yolk sac tumor. In all the tumors there was a prominent vascular proliferation composed of long thin-walled, curved vessels or a solid glomeruloid arrangement. Immunohistochemistry done in two cases confirmed the vascular nature of the proliferation. Angiogenesis, likely as an expression of vascular endothelial growth factors, is a well-known phenomenon in a variety of neural and neuroendocrine neoplasms, in particular high-grade gliomas. However, very few cases of this phenomenon have been described in association with neural tissue in the ovary. Recognition of this proliferation as a benign secondary one is important to avoid misdiagnosis of a vascular neoplasm or an immature teratoma, as happened in one of our cases.