RESUMEN
AIM: Seroepidemiological studies have given rise to the hypothesis that microorganisms like Chlamydia pneumoniae (CP), Helicobacter pylori (HP), cytomegalovirus (CMV), HCV types 1 and 2, and bacteria involved in dental or other unspecified infection sites may initiate or maintain the atherosclerotic process in lower limb arteries. However, not much attention has been attached to the patient's own limb skin and deep tissues bacterial flora, activated in ischemic tissues. This flora may enhance the inflammatory and thrombotic process in the atherosclerotic arteries. Lower limb tissues are exposed to microorganisms from the environment (foot) and microbes on floating epidermal cells from the perineal and anal regions. The aim of this paper was to identify microbial cells and their DNA in perivascular tissues and arterial walls of lower limbs. METHODS: Bacterial cultures and PCR method for detection of 16sRNA and immunohistopathological staining for identification of immune cells infiltrating vascular bundles. RESULTS: 1) specimens of atherosclerotic calf and femoral arteries contained bacterial isolates and/or their DNA, whereas, in control normal cadaveric organ donors' limb arteries or patients' carotid arteries and aorta bacteria they were detected only sporadically; 2) lower limb lymphatics contained bacterial cells in 76% of specimens, whereas controls only in 10%; 3) isolates from limb arteries and lymphatics belonged in majority to the coagulase-negative staphylococci and S.aureus, however, other highly pathogenic strains were also detected; 4) immunohistopathological evaluation arterial walls showed dense focal infiltrates of granulocytes and macrophages. CONCLUSION: Own bacterial isolates can be responsible for dense neutrophil and macrophage inflitrates of atherosclerotic walls and periarterial tissue in lower limbs and aggravate the ischemic changes.
Asunto(s)
Aterosclerosis/microbiología , Arteria Femoral/microbiología , Inflamación/microbiología , Extremidad Inferior/irrigación sanguínea , Arteria Poplítea/microbiología , Piel/microbiología , Staphylococcus/aislamiento & purificación , Arterias Tibiales/microbiología , Anciano , Aterosclerosis/inmunología , Aterosclerosis/patología , Aterosclerosis/cirugía , Estudios de Casos y Controles , Femenino , Arteria Femoral/inmunología , Arteria Femoral/patología , Arteria Femoral/cirugía , Granulocitos/inmunología , Granulocitos/patología , Humanos , Inmunohistoquímica , Inflamación/inmunología , Inflamación/patología , Inflamación/cirugía , Vasos Linfáticos/microbiología , Macrófagos/inmunología , Macrófagos/patología , Masculino , Persona de Mediana Edad , Arteria Poplítea/inmunología , Arteria Poplítea/patología , Arteria Poplítea/cirugía , Ribotipificación , Staphylococcus/clasificación , Staphylococcus/genética , Staphylococcus aureus/aislamiento & purificación , Arterias Tibiales/inmunología , Arterias Tibiales/patología , Arterias Tibiales/cirugíaRESUMEN
The 'oxidation theory' of atherosclerosis proposes that oxidation of low density lipoprotein (LDL) contributes to atherogenesis. Although the precise mechanisms of in vivo oxidation are widely unknown, increasing evidence suggests that myeloperoxidase (MPO, EC 1.11.1.7), a protein secreted by activated phagocytes, generates modified/oxidized (lipo)proteins via intermediate formation of hypochlorous acid (HOCl). In vitro generation of HOCl transforms lipoproteins into high uptake forms for macrophages giving rise to cholesterol-engorged foam cells. To identify HOCl-modified-epitopes in human plaque tissues we have raised monoclonal antibodies (directed against human HOCl-modified LDL) that do not cross-react with other LDL modifications, i.e. peroxynitrite-LDL, hemin-LDL, Cu2+-oxidized LDL, 4-hydroxynonenal-LDL, malondialdehyde-LDL, glycated-LDL, and acetylated-LDL. The antibodies recognized a specific epitope present on various proteins after treatment with OCl- added as reagent or generated by the MPO/H2O2/halide system. Immunohistochemical studies revealed pronounced staining for HOCl-modified-epitopes in fibroatheroma (type V) and complicated (type VI) lesions, while no staining was observed in aortae of lesion-prone location (type I). HOCl-oxidation-specific epitopes are detected in cells in the majority of atherosclerotic plaques but not in control segments. Staining was shown to be inside and outside monocytes/macrophages, endothelial cells, as well as in the extracellular matrix. A similar staining pattern using immunohistochemistry could be obtained for MPO. The colocalization of immunoreactive MPO and HOCl-modified-epitopes in serial sections of human atheroma (type IV), fibroatheroma (type V) and complicated (type VI) lesions provides further convincing evidence for MPO/H2O2/halide system-mediated oxidation of (lipo)proteins under in vivo conditions. We propose that MPO could act as an important link between the development of atherosclerotic plaque in the artery wall and chronic inflammatory events.