Replication in restenotic atherectomy tissue.

Previously, we demonstrated that replication in restenotic coronary atherectomy specimens was an infrequent and modest event. In general, this data was interpreted with caution, as immunocytochemistry for the proliferating cell nuclear antigen (PCNA) was used to subjectively assess proliferation and most of the tissue specimens were resected more than 3 months after the initial interventional procedure. The purpose of the present study was to use a more sensitive method of detecting replication, in situ hybridization for histone 3 (H3) mRNA, to determine the replication profile of human directional atherectomy specimens.

Monoclonality of smooth muscle cells in human atherosclerosis.

Atherosclerotic plaques contain a large monoclonal population of cells. Monoclonality could arise by somatic mutation, selection of a pre-existing lineage, or expansion of a pre-existing (developmental) clone. To determine the monoclonal cell type in plaque and learn when monoclonality arises, we studied X chromosome inactivation patterns using methylation of the X-linked human androgen receptor gene.

Chlamydia pneumoniae (TWAR) in coronary arteries of young adults (15-34 years old).

An association of Chlamydia pneumoniae with atherosclerosis of coronary and carotid arteries and aorta has been found by seroepidemiology and by demonstration of the organism in atheromata. Age-matched control tissue from persons without atherosclerosis was usually not available. We studied autopsy tissue from young persons, many with no atherosclerosis, to determine whether C.

Molecular mimicry: histone H3 and mycobacterial protein epitopes.

A 15-kDa protein detected initially in amyloidotic ileum from a transgenic mouse and subsequently in control (nontransgenic) ileum by various polyclonal rabbit antiserums applied to electroblots of extracts derived from these tissues was identified by partial sequence analysis as histone H3. Antiserums were made against immunogens unrelated to the histone, but they recognized calf thymus histone H3 (14.7 kDa) on Western blots.

Human serum amyloid A genes are expressed in monocyte/macrophage cell lines.

Serum amyloid A (apoSAA) is a family of proteins found, mainly associated with high density lipoproteins, in the blood plasma of mammals and at least one avian species, the Pekin duck. These proteins are present in small amounts under normal circumstances, but their concentration is capable of rising 100- to 1,000-fold in situations involving tissue injury or infection. Like classic acute phase proteins they are produced in the liver; however, expression of one of the apoSAA genes is known to occur in activated macrophages of mice.

Expression of apolipoprotein serum amyloid A mRNA in human atherosclerotic lesions and cultured vascular cells: implications for serum amyloid A function.

Altered lipoprotein metabolism and vascular injury are considered to be major parts of the pathogenesis of atherosclerotic lesions. Serum amyloid A (SAA) is a family of acute-phase reactants found residing mainly on high density lipoproteins (HDL) in the circulation. Several functions for the SAAs have been proposed that could be important in atherosclerosis.

Chlamydia pneumoniae, strain TWAR and atherosclerosis.

Infection with Chlamydia pneumoniae, strain TWAR, has been associated with atherosclerotic cardiovascular disease in two types of investigations, seroepidemiological and morphological-molecular. A series of seroepidemiological studies from Finland and the United States have shown a statistically significant association between several types of TWAR antibody, including immune complexes, and atherosclerotic disease of the coronary and carotid arteries. The morphological-molecular studies have shown the C.

Detection of Chlamydia pneumoniae in aortic lesions of atherosclerosis by immunocytochemical stain.

Recent evidence has shown the presence of Chlamydia pneumoniae antigens and nucleic acid in coronary artery atheromas from autopsy patients in South Africa. In this study, the immunocytochemical technique was used to demonstrate C pneumoniae antigens in atheromas of the aorta in autopsy patients from retrospective aortic atherosclerosis studies at the University of Washington. The patients were 34 to 58 years old.

Proliferation in primary and restenotic coronary atherectomy tissue. Implications for antiproliferative therapy.

On the basis of animal models of arterial injury, smooth muscle cell proliferation has been posited as a dominant event in restenosis. Unfortunately, little is known about this proliferation in the human restenotic lesion. The purpose of this study was to determine the extent and time course of proliferation in primary and restenotic coronary atherectomy-derived tissue.

Preservation of RNA for in situ hybridization: Carnoy's versus formaldehyde fixation.

Tissues fixed with organic solvent fixatives such as Carnoy's solution are known to give poor and erratic results with in situ hybridization, whereas those fixed with paraformaldehyde produce more consistent results. To understand this difference and to improve the utility of Carnoy's-fixed tissue for in situ hybridization, we explored several parameters of RNA integrity and preservation. Carnoy's-fixed, paraffin-embedded livers and paraformaldehyde-fixed, paraffin-embedded livers of mice were compared for RNA extractability, degradation, and hybridizability.

Murine serum amyloid A3 is a high density apolipoprotein and is secreted by macrophages.

The serum amyloid A (SAA) proteins make up a multigene family of apolipoproteins associated with high density lipoproteins. They are of ancient origin; the finding of a highly homologous protein in mammals and ducks indicates that SAAs have been in existence for at least 300 million years. The interspecies similarity among the SAAs makes the mouse, in which they have been most thoroughly studied, a reasonable model to use for defining the function(s) of this family of proteins in humans.

Immortalization of primary human smooth muscle cells.

Primary human aortic and myometrial smooth muscle cells (SMCs) were immortalized using an amphotropic recombinant retroviral construct containing the E6 and E7 open reading frames (ORFs) of human papillomavirus type 16. The SMCs expressing the E6/E7 ORFs have considerably elevated growth rates when compared with nonimmortalized control cells and show no signs of senescence with long-term passage. The first SMC line derived in this study has been maintained in continuous tissue culture for greater than 1 year (greater than 180 population doublings).

Cell proliferation in human coronary arteries.

Despite the lack of direct evidence for cell multiplication, proliferation of smooth muscle cells in human atherosclerotic lesions has been assumed to play a central role in ontogeny of the plaque. We used antibodies to cell cycle-related proteins on tissue sections of human arteries and coronary atherosclerotic plaques. Specific cell types were identified by immunochemical reagents for smooth muscle, monocyte-macrophages, and other blood cells.

What role(s) may extracellular matrix, particularly heparan sulfate, play in amyloid of Alzheimer's disease.

The authors of this article present and attempt to substantiate the thesis that proteoglycan(s), mainly heparan sulfate, are an important ingredient in the pathogenesis of the amyloid found in persons with Alzheimer's disease. Evidence presented indicates that glycosaminoglycans are regular constituents of many amyloid substances including that of senile plaques and congophilic angiopathy of Alzheimer's disease. It is proposed that the proteoglycans play a role in amyloidogenesis by one or a combination of the following mechanisms: 1) inducing amyloid fibrils containing a predominant beta-pleated sheet structure, 2) influencing amyloid deposition to occur at specific tissue sites and/or 3) prevent amyloid degradation.

Serum amyloid A in the mouse. Sites of uptake and mRNA expression.

Murine serum amyloid A1 (SAA1) and serum amyloid A2 (SAA2) are circulating, acute phase, high density apolipoproteins of unknown function. To pursue issues relating to their possible function their uptake and formation were studied. Kinetics of SAA protein distribution and gene expression after acute phase stimulation by casein or lipopolysaccharide were examined using immunocytochemistry for protein and RNA blot and in situ hybridization with probes for SAA1 and SAA2 mRNA.

Expression of the third member of the serum amyloid A gene family in mouse adipocytes.

Three homologous genes that code for three related proteins comprise the serum amyloid A (SAA) family in the mouse. Endotoxin induces equally vigorous expression of mRNAs for the three SAA genes in liver. In extrahepatic tissues SAA1 and/or SAA2 mRNAs have been found only in kidney and intestine, however, SAA3 is expressed in all extrahepatic tissues thus far examined.

Rat tissues express serum amyloid A protein-related mRNAs.

Serum amyloid A (SAA) is a small (12 kDa) acute-phase apoprotein of high density lipoprotein found in mammals. It is also the precursor to amyloid protein A, the main protein constituent of fibrils found in amyloidosis secondary to chronic or recurrent inflammation--e.g.

Origins of human atherosclerotic plaques. The role of altered gene expression.

The dramatic rise and equally dramatic fall in the mortality from coronary heart disease in the 20th century is only partly explained. This article reviews the development of our ideas concerning possible pathways other than lipids that might play a role in the development of human atherosclerosis alone or in combination with one or more of the usually considered risk factors. In some instances, such as that of cigarette smoking, the proposed concept regarding genetic alterations in vascular smooth muscle suggests a mechanism for development of at least some of the lesions.

Platelet-derived growth factor gene expression in human atherosclerotic plaques and normal artery wall.

We previously demonstrated that the B chain of platelet-derived growth factor (PDGF-B) is transcribed in human atherosclerotic plaques, indicating that production of growth factors within plaques could occur during atherogenesis. However, since atherosclerotic plaques are composed of several cell types and three of these--macrophages, endothelial cells, and smooth muscle cells--can express the PDGF genes, the cell type responsible for PDGF gene expression was not clear. In the present study we explore further the expression of PDGF-A and -B and identify transcriptionally active cell types.

Expression and developmental control of platelet-derived growth factor A-chain and B-chain/Sis genes in rat aortic smooth muscle cells.

Cultured arterial smooth muscle cells (SMC) can produce platelet-derived growth factor (PDGF)-like molecules. This property raises the possibility that SMC-derived PDGFs function as autocrine/paracrine regulators in the formation and maintenance of the artery wall. In this study we have asked if levels of mRNAs directing synthesis of PDGF are modulated in aortic SMC during postnatal development.

Differential expression of the amyloid SAA 3 gene in liver and peritoneal macrophages of mice undergoing dissimilar inflammatory episodes.

The three active serum amyloid A (SAA) genes of mice, SAA 1, SAA 2, and SAA 3, are coordinately expressed in liver during acute and chronic inflammatory stimulation and experimental amyloidosis. The genes, primarily SAA 3, are also expressed extrahepatically. The apoprotein SAA 2 is the precursor of the amyloid A (AA) fibril protein that is deposited as insoluble fibrils extracellularly in spleen and other organs when amyloidosis occurs secondarily to inflammation.

Primary structure of duck amyloid protein A. The form deposited in tissues may be identical to its serum precursor.

The amino acid sequence has been determined for the major protein that accumulates in amyloid fibrils in tissues of the Pekin duck. With the exception of 16 residues at the amino terminus, this 106-residue protein is homologous with human serum amyloid protein A (104-residue apoSAA), which is the putative precursor of the 76-residue protein that accumulates in human patients with amyloidosis. Duck serum is shown to contain a protein that is immunologically related and approximately equal in size (12 kDa) to the deposited form in ducks.

sis (platelet-derived growth factor B chain) gene transcript levels are elevated in human atherosclerotic lesions compared to normal artery.

Arterial smooth muscle cell (SMC) proliferation is thought to be an essential aspect of the development of human atherosclerotic lesions. In this study we posed the question, could a growth factor gene be transcriptionally active in atherosclerotic tissue? We found that transcripts from the sis gene, which encodes one of the two chains of platelet-derived growth factor, were present in surgically removed human carotid artery lesions at levels 5-fold greater than the low level of constitutive expression detected in normal artery. This demonstrates that a growth factor could be synthesized endogenously within human atherosclerotic lesions.