RESUMEN
BACKGROUND: The application of an exogenous pulmonary surfactant as a carrier for intratracheally administered antimicrobials represents a promising therapeutic modality that is still on its way to clinical practice. Owing to its ability to decrease surface tension, exogenous surfactant may enhance delivery of antibiotics into foci of pulmonary infection, thus increasing efficiency and safety of topical antimicrobial therapy in bacterial lung diseases. OBJECTIVES: To assess potential interactions between exogenous surfactant and amikacin in vitro, and to study the effects of their joint intratracheal instillation in rats with acute pneumonia caused by Pseudomonas aeruginosa. METHODS: The antibacterial and surface-active properties of amikacin (Amicil, Kievmedpreparat, Ukraine), porcine pulmonary surfactant (Suzacrin, Docpharm, Ukraine), and their combination were studied in vitro using standard microbiologic procedures and modified Pattle method (estimation of bubble diameter). Similar methods were utilized to study bacterial contamination of lungs and blood, and to assess the surface activity of bronchoalveolar wash (BAW) in 119 Wistar rats, including infected (intratracheal introduction of P. aeruginosa ATCC 27853) and noninfected animals. Histopathologic findings, differential leukocyte counts, and oxygenation parameters were recorded. RESULTS: Antibacterial and surface-active properties of the surfactant and amikacin remained unimpaired in vitro. In rats anti-pseudomonal and anti-inflammatory effects of the surfactant-amikacin mixture were more pronounced (p<0.05) than effects of pure amikacin as evidenced by recorded rates of bacterial growth and granulocytic response. The combined therapy considerably restricted tissue damage and mitigated reduction of BAW surface activity. CONCLUSION: The advantages of the joint surfactant-amikacin therapy of Pseudomonas-induced pneumonia may suggest further clinical trials.
Asunto(s)
Amicacina/administración & dosificación , Antibacterianos/administración & dosificación , Pulmón/efectos de los fármacos , Neumonía Bacteriana/tratamiento farmacológico , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/efectos de los fármacos , Surfactantes Pulmonares/administración & dosificación , Administración por Inhalación , Amicacina/química , Animales , Antibacterianos/química , Química Farmacéutica , Modelos Animales de Enfermedad , Portadores de Fármacos , Combinación de Medicamentos , Pulmón/microbiología , Pulmón/patología , Masculino , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/patología , Infecciones por Pseudomonas/microbiología , Infecciones por Pseudomonas/patología , Pseudomonas aeruginosa/patogenicidad , Surfactantes Pulmonares/química , Ratas WistarRESUMEN
The overall mortality of diabetic patients after myocardial infarction is 3-4 times higher than non-diabetics. The cellular mechanisms underlying such a poor clinical prognosis remain incompletely understood. Recent reports suggest that lipotoxicity associated with impaired liporegulation is among the leading factors in the pathogenesis of type 2 diabetes. The goal of this study was to investigate whether excess lipid accumulation specifically in heart muscle cells contributes to the expansion of myocardial infarction in type 2 diabetic patients. Comparative structural analysis of cardiac tissue was performed on autopsy samples from the infracted hearts of diabetic and non-diabetic individuals with special reference to the expansion of the infarction, degenerative changes, lipoatrophy, cell death, and replacement fibrosis. We found that progressive accumulation of lipids in cardiac myocytes was accompanied by considerable loss of myofibrils and was frequently observed in the heart tissue of type 2 diabetic patients. This indicates that disassembly of the contractile apparatus in the cells infiltrated with lipids weakens their capability for functional activity. Analysis of degenerative changes in the diabetic tissue has shown that lipid-laden cardiac myocytes were more susceptible to necrotic and apoptotic cells death leading to expansion of the infarction and the development of progressive focal replacement fibrosis both in the perinecrotic zone and in the areas located far from the site of injury. Our data show that lipoatrophy and loss of muscle cells during the post-infarction period aggravate the functional impairment in the diabetic heart and limits its adaptive capacity for compensatory remodeling. This suggests that lipotoxic myocardial injury associated with defects of lipid metabolism in type 2 diabetes predisposes its evolution toward congestive heart failure and is an important factor contributing to a high mortality following infarction.