Biomedical subjects

Ivana Kholová

Publications and source records attributed to Ivana Kholová.

12 recordsLinked to original sources

PubMed2006

Short and long-term effects of hVEGF-A(165) in Cre-activated transgenic mice.

We have generated a transgenic mouse where hVEGF-A(165) expression has been silenced with loxP-STOP fragment, and we used this model to study the effects of hVEGF-A(165) over-expression in mice after systemic adenovirus mediated Cre-gene transfer. Unlike previous conventional transgenic models, this model leads to the expression of hVEGF-A(165) in only a low number of cells in the target tissues in adult mice. Levels of hVEGF-A(165) expression were moderate and morphological changes were found mainly in the liver, showing typical signs of active angiogenesis. Most mice were healthy without any major consequences up to 18 months after the activation of hVEGF-A(165) expression. However, one mouse with a high plasma hVEGF-A(165) level died spontaneously because of bleeding into abdominal cavity and having liver hemangioma, haemorrhagic paratubarian cystic lesions and spleen peliosis. Also, two mice developed malignant tumors (hepatocellular carcinoma and lung adenocarcinoma), which were not seen in control mice. We conclude that long-term uncontrolled hVEGF-A(165) expression in only a limited number of target cells in adult mice can be associated with pathological changes, including possible formation of malignant tumors and uncontrolled bleeding in target tissues. These findings have implications for the design of long-term clinical trials using hVEGF-A(165) gene and protein.

Adenoviridae↗

PubMed2006

Neoplastic transformation of the thyroid gland is accompanied by changes in cellular sialylation.

Cancer of the thyroid gland is one of the most common endocrine diseases. Histological evaluation is often complicated by difficulty in distinguishing between benign and malignant lesions. Abnormal glycosylation of cell structures, including changes in sialylation, is a feature of the neoplastic transformation process. The aim of this study was to evaluate associations between neoplastic changes in the thyroid gland and changes in sialylation, with reference to its terminal linkage type. Lectin histochemistry using three sialic acid-binding lectins: Tritrichomonas mobilensis lectin (TML), which recognizes sialic acid without linkage preference; Maackia amurensis leukoagglutinin (MAL), which preferentially binds alpha-2,3-linked sialic acid; and Sambucus nigra agglutinin (SNA), which preferentially binds alpha-2,6-linked sialic acid, were used for detection of sialylated glycoconjugates in 50 human thyroid gland specimens. These included papillary, follicular, oncocytic, medullary and anaplastic carcinomas, follicular adenomas and benign follicular and parenchymatous goiter. The luminal surface of follicular cells in normal thyroid glands, adenomas and goiters showed weak or absent labelling for sialic acid. Malignant transformation of the gland was accompanied by an increase of sialic acid positivity on follicular epithelial cells, especially of alpha-2,3-linked sialic acid. Strong luminal positivity for sialic acid was found in papillary carcinomas, whereas moderate positivity was seen in follicular carcinomas. Inconsistent, weak positivity for sialic acid was documented in medullary and anaplastic carcinomas. Increased membrane sialic acid on thyroid gland cells may be an important diagnostic pathological finding, that could be useful in distinction of malignant from benign thyroid lesions, especially with respect to aspiration cytology diagnostics.

Cell Transformation, Neoplastic↗

PubMed2006

Myocardial sleeves of pulmonary veins and atrial fibrillation: a postmortem histopathological study of 100 subjects.

Atrial fibrillation (AF) is triggered by ectopic beats originating from extensions of the left atrial myocardium over the pulmonary veins (PVs), so-called myocardial sleeves. A total of 100 hearts (393 PVs) obtained at autopsy were studied. Of these, 50 were from patients with chronic AF and 50 from controls in sinus rhythm. Out of a total of 393 PVs studied, a sleeve was present in 349 PVs (88.8%). The myocardial sleeves frequently harboured senile atrial amyloid and scarring. These two changes were evaluated semi-quantitatively (grade 0-3). Amyloidosis was found in 68% of all hearts and in 55% of all sleeves. It was more frequent in patients with AF (58.5%) than in those without (51.7%), however, without statistical significance (p values 0.948, 0.306, 0.166 and 1). Scarring was present in all 349 sleeves studied. It was significantly more severe in patients with AF (average grade 2.44) than in those without (average grade 2.00) (p values <0.001, <0.1, <0.05 and <0.01). In conclusion, amyloidosis and particularly scarring of the myocardial sleeves of the pulmonary veins, appear to be common in the elderly population as an arrhythmogenic substrate for AF.

Aged↗

PubMed2006

Current treatment in cardiac amyloidosis.

Involvement of the heart is a common finding in amyloidosis. The heart is usually infiltrated by amyloid fibrils in primary amyloidosis and age-related forms of amyloidosis, less commonly in transthyretin familial amyloidosis, and rarely in secondary amyloidosis. The most common clinical presentation is restrictive cardiomyopathy with right-sided heart failure. The second most frequent presentation is congestive heart failure due to systolic dysfunction, followed by arrhythmias and orthostatic hypotension. The diagnosis of amyloidosis requires tissue sample confirmation; at present, Congo red staining in polarized light is the diagnostic method of choice. The characterization of protein fibril type by immunohistochemistry or biochemistry is essential for patient prognosis and treatment. The therapeutic approach consists of specific treatment of amyloidosis and supportive treatment for cardiac-related symptoms. The treatment depends on the type of amyloidosis and the stage of disease. The mainstay of supportive treatment of cardiac failure is diuretic therapy. Primary amyloidosis treatment protocol includes melphalan and prednisone chemotherapy. Heart transplantation is only a palliative treatment. Stem cell transplantation is an emerging treatment alternative. Combination therapy of melphalan and stem cell transplantation has been shown to be a promising treatment strategy. Secondary amyloidosis requires aggressive treatment of the associated inflammatory and neoplastic process. Age-related (senile) amyloidosis benefits from supportive cardiac treatment when applicable. Transthyretin amyloidosis, the most common cardiac hereditary amyloidosis, is treated by liver or combined liver-heart transplantation. New therapies based on chemical and immunologic reaction with amyloid or its precursor are under intensive development.

Journal Article↗

PubMed2005

Blood flow remodels growing vasculature during vascular endothelial growth factor gene therapy and determines between capillary arterialization and sprouting angiogenesis.

BACKGROUND: For clinically relevant proangiogenic therapy, it would be essential that the growth of the whole vascular tree is promoted. Vascular endothelial growth factor (VEGF) is well known to induce angiogenesis, but its capability to promote growth of larger vessels is controversial. We hypothesized that blood flow remodels vascular growth during VEGF gene therapy and may contribute to the growth of large vessels. METHODS AND RESULTS: Adenoviral (Ad) VEGF or LacZ control gene transfer was performed in rabbit hindlimb semimembranous muscles with or without ligation of the profound femoral artery (PFA). Contrast-enhanced ultrasound and dynamic susceptibility contrast MRI demonstrated dramatic 23- to 27-fold increases in perfusion index and a strong decrease in peripheral resistance 6 days after AdVEGF gene transfer in normal muscles. Enlargement by 20-fold, increased pericyte coverage, and decreased alkaline phosphatase and dipeptidyl peptidase IV activities suggested the transformation of capillaries toward an arterial phenotype. Increase in muscle perfusion was attenuated, and blood vessel growth was more variable, showing more sprouting angiogenesis and formation of blood lacunae after AdVEGF gene transfer in muscles with ligated PFA than in normal muscles. Three-dimensional ultrasound reconstructions and histology showed that the whole vascular tree, including large arteries and veins, was enlarged manifold by AdVEGF. Blood flow was normalized and enlarged collaterals persisted in operated limbs 14 days after AdVEGF treatment. CONCLUSIONS: This study shows that (1) blood flow modulates vessel growth during VEGF gene therapy and (2) VEGF overexpression promotes growth of arteries and veins and induces capillary arterialization leading to supraphysiological blood flow in target muscles.

Adenoviridae↗

PubMed2005

Gene transfers of vascular endothelial growth factor-A, vascular endothelial growth factor-B, vascular endothelial growth factor-C, and vascular endothelial growth factor-D have no effects on atherosclerosis in hypercholesterolemic low-density lipoprotein-receptor/apolipoprotein B48-deficient mice.

BACKGROUND: The role of vascular endothelial growth factors (VEGFs) in large arteries has been proposed to be either vasculoprotective or proatherogenic. Because VEGF family members are used for human therapy, it is important to know whether they could enhance atherogenesis. We tested the effects of the members of the VEGF gene family on atherogenesis in LDL-receptor/apolipoprotein (apo) B48 double-knockout (LDLR/apoB48) mice using systemic adenoviral gene transfer. METHODS AND RESULTS: Six groups of LDLR/apoB48-deficient mice (n=110) were kept 3 months on a Western-type diet. After 6 weeks of diet, mice were injected via tail vein with recombinant adenoviruses expressing VEGF-A, -B, -C, or -D or LacZ (1 x 10(9) PFU) or rhVEGF-A protein (2 microg/kg) and euthanized 6 weeks later. Also, older mice (n=36) were injected after 4 months on the diet and euthanized 6 weeks later (total time on the diet, 22 weeks) to evaluate the effects of gene transfers on the development of more mature lesions. Aortas were analyzed for the presence of macroscopic lesions, cross-sectional lesion areas, neovascularization, and cellular composition of the lesions. All groups had equivalent plasma cholesterol and triglyceride levels. Gene transfers with recombinant adenoviruses or administration of rhVEGF-A protein had no statistically significant effects on en face atherosclerotic lesions in the aorta, cross-sectional lesion area, neovascularization, or cellular composition of the lesions. CONCLUSIONS: This study shows no proatherogenic effects of adenovirus-mediated gene transfers of VEGF-A, -B, -C, or -D in the LDLR/apoB48-deficient hypercholesterolemic mice, in which lipoprotein profile and atherosclerosis closely resemble those in human disease.

Adenoviridae↗

PubMed2004

Morphology of atrial myocardial extensions into human caval veins: a postmortem study in patients with and without atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) may be triggered from arrhythmogenic foci originating from atrial muscular sleeves that extend into the caval veins (CVs). The aim of this anatomic study was to evaluate both the extent and arrangement of atrial myocardial fibers in CVs in subjects with and without a history of AF. METHODS AND RESULTS: Twenty-five human autopsied hearts (15 men; mean age, 65.5+/-12 years; range, 39 to 80 years) were studied. Seven subjects had a previous history of AF. The presence and morphology of atrial myocardial extensions were studied microscopically in both CVs. Such extensions were found in 38 of 50 CVs (76%). Their average length in the superior vena cava reached 13.7+/-13.9 mm (maximum, up to 47 mm) and in the inferior vena cava, 14.6+/-16.7 mm (maximum, up to 61 mm). The thickness of atrial myocardium extending into the CVs was 1.2+/-1.0 mm (maximum, 4 mm) for the superior vena cava and 1.2+/-0.9 mm for the inferior vena cava (maximum, 3 mm). The majority of myocardial extensions revealed discontinuous and circular patterns. Degenerative changes were found in approximately half of the subjects. There was no significant difference between patients with and without a history of AF. CONCLUSIONS: Atrial myocardial extensions into both CVs are present in the majority of human beings, both with and without a history of AF. The extensions are localized on the outer side of venous adventitia. Arrangement, length, and thickness of myocardial sleeves onto the CVs vary individually, and many of them contain degenerative changes.

Adult↗

PubMed2004

Gene transfer into rabbit arteries with adeno-associated virus and adenovirus vectors.

BACKGROUND: Gene transfer offers considerable potential for altering vessel wall physiology and intervention in vascular disease. Therefore, there is great interest in developing optimal strategies and vectors for efficient, targeted gene delivery into a vessel wall. METHODS: We studied adeno-associated viruses (AAV; 9 x 10(8) to 4 x 10(9) TU/ml) for their usefulness to transduce rabbit arteries in vivo in comparison with adenoviruses (Adv; 1 x 10(9) to 1 x 10(10) pfu/ml). 100 microl of viruses or placebo solution were injected intraluminally into transiently isolated carotid segments. RESULTS: In normal arteries AAV transduced mainly medial smooth muscle cells (SMC) while Adv transduced exclusively endothelial cells (EC). Mechanical injury to EC layer and internal elastic lamina enabled Adv to penetrate and transduce medial SMC. Transgene expression in EC after the AAV-mediated gene transfer was very low. The use of the EC-specific Tie-1 promoter did not lead to specific transgene expression in EC. Transgene expression in SMC persisted for at least 100 days after the AAV treatment whereas the Adv-mediated effect diminished in 14 days. AAV caused only a modest increase in EC VCAM-1 expression and proliferation rate of vascular cells as compared with the mock-treated arteries while Adv caused an extensive inflammatory cell infiltration, VCAM-1 expression, vascular cell proliferation and morphological damages. CONCLUSIONS: Significant differences were observed between the AAV and the Adv vectors in their patterns of arterial transduction and consequent inflammatory responses. These distinct properties may be utilized for different applications in vascular biology research and gene therapy for cardiovascular diseases.

Adenoviridae↗

PubMed2003

VEGF-D is the strongest angiogenic and lymphangiogenic effector among VEGFs delivered into skeletal muscle via adenoviruses.

Optimal angiogenic and lymphangiogenic gene therapy requires knowledge of the best growth factors for each purpose. We studied the therapeutic potential of human vascular endothelial growth factor (VEGF) family members VEGF-A, VEGF-B, VEGF-C, and VEGF-D as well as a VEGFR-3-specific mutant (VEGF-C156S) using adenoviral gene transfer in rabbit hindlimb skeletal muscle. The significance of proteolytic processing of VEGF-D was explored using adenoviruses encoding either full-length or mature (DeltaNDeltaC) VEGF-D. Adenoviruses expressing potent VEGFR-2 ligands, VEGF-A and VEGF-DDeltaNDeltaC, induced the strongest angiogenesis and vascular permeability effects as assessed by capillary vessel and perfusion measurements, modified Miles assay, and MRI. The most significant feature of angiogenesis induced by both VEGF-A and VEGF-DDeltaNDeltaC was a remarkable enlargement of microvessels with efficient recruitment of pericytes suggesting formation of arterioles or venules. VEGF-A also moderately increased capillary density and created glomeruloid bodies, clusters of tortuous vessels, whereas VEGF-DDeltaNDeltaC-induced angiogenesis was more diffuse. Vascular smooth muscle cell proliferation occurred in regions with increased plasma protein extravasation, indicating that arteriogenesis may be promoted by VEGF-A and VEGF-DDeltaNDeltaC. Full-length VEGF-C and VEGF-D induced predominantly and the selective VEGFR-3 ligand VEGF-C156S exclusively lymphangiogenesis. Unlike angiogenesis, lymphangiogenesis was not dependent on nitric oxide. The VEGFR-1 ligand VEGF-B did not promote either angiogenesis or lymphangiogenesis. Finally, we found a positive correlation between capillary size and vascular permeability. This study compares, for the first time, angiogenesis and lymphangiogenesis induced by gene transfer of different human VEGFs, and shows that VEGF-D is the most potent member when delivered via an adenoviral vector into skeletal muscle.

Adenoviridae↗

PubMed2003

Anatomic characteristics of extensions of atrial myocardium into the pulmonary veins in subjects with and without atrial fibrillation.

Myocardial extensions around pulmonary veins (PVs) have been recognized as the most important sites of origin for arrhythmogenic foci that trigger atrial fibrillation. The aim of this study was to evaluate the characteristics of atrial myocardium in pulmonary veins from subjects with and without a history of atrial fibrillation. A total number of 43 human hearts obtained at autopsy were studied (27 men, 16 women, mean age 67 +/- 8 years). Sixteen subjects (group 1) had a history of atrial fibrillation (11 men, mean age 66 +/- 10 years). The remaining 27 subjects (group 2) were without arrhythmia (16 men, mean age 68 +/- 8 years). The presence and morphology of the myocardial extensions were studied microscopically. Of the total number of 172 PVs evaluated, myocardial extensions were revealed in 117 (68%) cases. Myocardial fibers were arranged in a variable manner with the most prevailing circular pattern. Continuous extensions were present in 74, while a discontinuous pattern was revealed in 29 PVs. Maximum extension of the sleeves reached 48 mm (mean 7.7-10 mm) and their maximum thickness was 5 mm. Myocardial extensions were longer and thicker in the upper PVs from subjects with previous atrial fibrillation. In conclusion, a significant interindividual variability in the presence, arrangement, and thickness of atrial myocardial sleeves into PVs was revealed. Patients with a history of atrial fibrillation were found to have longer and thicker myocardial extensions into the upper PVs, and this finding may have implications for the catheter ablation technique.

Aged↗

PubMed2002

Sialic acid expression in autoimmune thyroiditis.

Autoimmune diseases of the thyroid gland are among the most frequent endocrine disorders. The present study analyzes expression patterns of sialic acids in these diseases. Three lectins specific for sialic acids were used for the histochemical analysis of surgical specimens of the thyroid gland: Tritrichomonas mobilensis lectin that stains all types of sialic acids, Maackia amurensis leukoagglutinin that stains sialic acids with alpha2,3 linkage and Sambucus nigra agglutinin that stains sialic acids with alpha2,6 linkage. In autoimmune thyroiditis, there was a significant increase in sialic acid expression in epithelial cells, especially on luminal membranes of follicular cells. The alpha2,3 linkage dominated over the alpha2,6 linkage. Lymphocytes of patients with Hashimoto thyroiditis, especially in germinal centers, showed strong expression of alpha2,6-linked sialic acids on their cell membrane. Vascular endothelium was positive in all specimens. It can be concluded, that there is a significant increase in sialic acid expression in autoimmune diseases of the thyroid gland, predominantly of sialic acids with alpha2,3 linkage, whereas the sialylation pattern of lymphocytes in Hashimoto thyroiditis was also different.

Animals↗

PubMedDate not supplied

Expression of Leu-7 in myocardial sleeves around human pulmonary veins.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained clinical arrhythmia. Myocardial sleeves onto pulmonary veins (PVs) have been recognized as a frequent site of origin of focal triggers for this arrhythmia. Expression of Leu-7 has been hypothesized to correspond with abnormal atrial automaticity. OBJECTIVE: To evaluate a possible role of the Leu-7 immunoreactivity in AF patients, we studied Leu-7 expression in myocardial sleeves. METHODS: Leu-7 was studied immunohistochemically in paraffin-embedded specimens from 55 human autopsied hearts (mean age 69 years, range 42-94 years, 34 males, 21 females). Twenty-two of the subjects had previous history of AF. RESULTS: Myocardial sleeves were found in 151 out of a total number of 220 PVs (68.6%). Leu-7 granular cytoplasmatic positivity was observed in 15 (9.9%) PVs from 12 different hearts: 6 (15.4%) in the right superior, 4 (10.2%) in the right inferior, 4 (10.8%) in the left superior and 1 (2.7%) in the left inferior PV. This finding was revealed both in patients with and without the history of AF. CONCLUSIONS: Leu-7 positivity, hypothesized to correspond with abnormal atrial automaticity, can be detected in some myocardial sleeves around PVs. However, no statistical relationship to previous history of AF was found.

Adult↗