muramidase and Arteriosclerosis

Topics: Aging; Arteriosclerosis; Blood Coagulation; Bone Marrow Cells; Carrier Proteins; Cell Adhesion; Enzyme Inhibitors; Hematopoietic Stem Cells; Humans; Hydrolases; Kinetics; Liver; Lymph Nodes; Lysosomes; Macrophages; Monocytes; Muramidase; Peptide Hydrolases; Peroxides; Phagocytes; Receptor, Insulin; Spleen; Wound Healing

It is generally accepted that the foam cells in atherosclerotic lesions are derived mainly from monocytes/macrophages. We investigated whether the macrophage-derived foam cells, isolated from the atherosclerotic lesions of cholesterol-fed rabbits, would exhibit properties similar to those of blood monocytes in vitro and whether the cholesterol concentration of the macrophage-derived foam cells would decrease in the presence of an appropriate cholesterol acceptor in culture. We found that most (> 98%) of the foam cells isolated from atherosclerotic lesions were positive for anti-monocyte-macrophage antibody and nonspecific esterase. While almost all (> 98%) of the foam cells exhibited NaF-resistant, nonspecific esterase activity, the blood monocytes exhibited no such activity. Macrophage-derived foam cells contained larger amounts of cholesterol, most of it esterified, than the blood monocytes. Although blood monocytes exhibited a substantial amount of lysozyme, the freshly isolated, macrophage-derived foam cells showed no detectable lysozyme activity. The production of superoxide by macrophage-derived foam cells stimulated by PMA or opsonized zymosan was lower than that of stimulated monocytes. The cholesterol concentration of macrophage-derived foam cells decreased during five days of culture in the presence of an appropriate acceptor, such as normal and hypercholesterolemic rabbit serum and high density lipoprotein, although the rate of decrease was slow. Results suggest that macrophage-derived foam cells may be involved in both the progression and the regression of early atherosclerotic lesions.

Topics: Animals; Arteriosclerosis; Cholesterol; Esterases; Foam Cells; Glucuronidase; Macrophages; Male; Muramidase; Rabbits; Superoxides

We studied the antigenic markers of macrophages (Mphs) in atherosclerotic human arteries by immunohistochemistry and compared them with the patterns in Mph subpopulations of tonsil and lymph node, which are also described. The staining of atheroma intimal Mphs was assessed semiquantitatively in the subendothelial, mid, and outer intima. Three patterns of reactivity with Mph antibodies were recognized. (a) Pan-Mph (antibodies HAM56, EBM11, and CD14 group). Staining was maximal in the mid-intimal zone. (b) Subendothelial Mphs (anti-muramidase, anti-alpha-1-antitrypsin and MAC387). In lymphoid tissue, sinusoidal Mphs and a few inflammatory Mphs were stained, as well as blood monocytes. This group of antibodies recognizes Mphs that are likely to be recently blood-derived (RBD-Mphs). (c) Antibodies reactive with various histiocyte populations in lymphoid tissues (anti-Factor XIII; anti-HLA Class II and LN2) also gave maximal staining in the mid-intimal zone, but differences between lesion types suggest that they are recognizing heterogeneous subpopulations of Mphs. These observations demonstrate the heterogeneity of tissue Mphs and suggest that an insight into the dynamics of tissue Mphs can be obtained from the cell phenotype. They indicate that all stages of atherosclerosis can have an outward traffic of Mphs from the blood through the arterial intima.

Topics: alpha 1-Antitrypsin; Antibodies, Monoclonal; Antigens, Differentiation; Arteriosclerosis; Cell Differentiation; Coronary Vessels; Humans; Immunoenzyme Techniques; Immunohistochemistry; Lymph Nodes; Lymphoid Tissue; Macrophages; Muramidase; Neovascularization, Pathologic; Palatine Tonsil; T-Lymphocytes

Atherosclerosis was induced in male mongrel rabbits with a high-fat diet and the influence of essential phospholipids (EPL) on plaque formation, parameters of lipid metabolism and immunological functions was studied. When EPL were added to the high-fat diet there was a significant reduction in the area of atherosclerotic involvement of the aorta. The serum concentration of lipids decreased, often to normal values, and cholesterol esterified with polyunsaturated fatty acids appeared. Normalization of the malonyldialdehyde level in plasma was accompanied by a decrease in the concentration of ascorbate free radicals in blood and liver. The high-fat diet caused a depression of both non-specific and specific immune functions studied. With EPL in the diet the tests showed near normal or normal values. It is inferred from these results that a normal state of the immune system is important for preventing the progress of atherosclerotic changes. This is discussed with reference to the role of some immune cells in the metabolism of lipids and to participation of essential phospholipids in plasma membrane functions.

Topics: Animals; Aorta; Arteriosclerosis; Dietary Fats; Fatty Acids, Nonesterified; Hemagglutinins; Lipids; Lymphocyte Activation; Male; Malondialdehyde; Muramidase; Phagocytosis; Phospholipids; Rabbits

A total of 13 forty-day-old male Japanese quails had free access to a atherogenic diet containing 15% corn oil and 2% cholesterol or commercial basal diet for 3 months. Birds fed basal diet showed no significant intimal lesions. These birds had two types of cells, i.e. smooth muscle cell and fibroblast-like cell, in the tunica media of the ascending aorta. While fat-fed birds showed marked lipid-rich intimal lesions in the ascending aorta but not in the abdominal aorta. Some macrophage-derived foam cells, which were stained for lysozyme and OKM1, were demonstrated in the superficial portion of the thickened intima. The majority of the cells in the lipid-rich thickened intima showed ultrastructural character of fibroblast-like cells with or without lipid droplets. Alpha-1-antichymotrypsin was positive for fibroblast-like cells in the thickened intima but not for those in the tunica media of the ascending aorta. These results suggest that metaplasia of the medial fibroblast-like cells is responsible for the development of atherosclerosis in the quail.

Topics: alpha 1-Antichymotrypsin; Animals; Antigens, Surface; Aorta; Aortic Diseases; Arteriosclerosis; Coturnix; Diet, Atherogenic; Fibroblasts; Foam Cells; Immunohistochemistry; Male; Muramidase

The lysocyme activity in blood serum and liver hemogenate of rats and rabbits at hyperlipidemia and atherosclerosis and its treatment with some new compounds or chemicals has been studied. A change of natural resistance of the body at hyperlipidemia and atherosclerosis characterized by the increase of serum lysocyme activity has been found. Preparations used in this work exerted mobilizing effect on the level of serum lysocyme activity but their influence on the functional state of the liver was different.

Topics: Adjuvants, Immunologic; Animals; Arteriosclerosis; Enzyme Activation; Hypercholesterolemia; Hyperlipidemias; Hypolipidemic Agents; Immunity, Innate; Liver; Muramidase; Niacin; Rabbits; Rats; Triglycerides

A variable population of fat-filled "foam" cells in diet-induced experimental arterial intimal plaques of rabbits and monkeys were analyzed for several features characteristic of macrophages. These included: 1) surface binding and phagocytosis of antibody-coated or complement-coated erythrocytes to detect specific surface receptors; 2) cytochemical tests and ultrastructural features to evaluate cell function and structure; and 3) rapid adherence to glass, a feature of macrophage activity, to isolate and identify a homogeneous population of fat-filled foam cells from excised and disrupted arterial lesions. Mixed populations of cells grown in culture from explants of lesions were also analyzed and lipid-filled cells were studied in histologic sections of adjacent lesions. Eighty to ninety percent of the easily dislodged glass-adherent cells from lesions had surface receptors for the Fc portion of immunoglobulin G and for the third component of complement. Coated red blood cells were readily phagocytized, but noncoated cells were not. Acid lipase activity was demonstrated in the Fc-receptor-positive cells. These cells were also devoid of ultrastructural features of smooth muscle. Among the cells growing or migrating out of explants, a population of large round foam cells possessed all of the macrophage features found in the glass-adherent cells from lesions and lacked ultrastructural characteristics of smooth muscle. Fusiform lipid vacuolated cells also grew out of the explants but did not exhibit surface receptors, failed to phagocytize coated or noncoated erythrocytes and did not stain for acid lipase activity; these cells showed distinctive morphologic features of smooth muscle. In histologic sections of nearby lesions foam cells that showed macrophage characteristics, ie, acid lipase activity and the presence of lysozymelike antigen, lacked ultrastructural smooth muscle features. Smooth muscle cells in lesion sections often contained lipid but demonstrated no lysozyme or acid lipase activity. The occurrence of a population of cells with several functional and structural features of macrophages among the lipid-laden cells of experimental diet-induced arterial lesions suggests that some foam cells may be derived from monocytes. An alternative explanation, that metabolically altered autochthonous arterial wall cells assume one or more characteristics of mononuclear phagocytes is less likely, since some of the markers used in these experiments are unrelated.

Topics: Animals; Aorta; Arteriosclerosis; Carotid Arteries; Erythrocytes; Femoral Artery; Foam Cells; Haplorhini; Immunoglobulin G; Lipase; Macrophages; Male; Muramidase; Muscle, Smooth; Phagocytosis; Rabbits; Receptors, Complement; Receptors, Fc; Receptors, Immunologic; Rosette Formation

Topics: Animals; Arteriosclerosis; Cartilage; Muramidase; Rats

Topics: Animals; Arteriosclerosis; Cartilage; Disease Models, Animal; Female; Muramidase; Rats

Topics: Antibodies; Arteriosclerosis; Blood Vessels; Brain; Cardiovascular Diseases; Cerebrovascular Disorders; Endarteritis; Humans; Hypertension; Muramidase

Topics: Adult; Aged; Aorta; Arteriosclerosis; Arthritis, Rheumatoid; Collagen; Connective Tissue; Ear Ossicles; Female; Galactosidases; Gastric Mucosa; Glycoside Hydrolases; Hepatitis A; Histocytochemistry; Humans; Hyaluronoglucosaminidase; Hydrochloric Acid; Hydroxides; Liver Diseases; Macromolecular Substances; Male; Microbial Collagenase; Middle Aged; Muramidase; Neuraminidase; Otosclerosis; Sodium Chloride; Stomach Ulcer; Synovial Membrane; Urea