Lymphatic pump treatment enhances the clearance of pneumonia

Abstract

BackgroundOsteopathic lymphatic pump treatments (LPT) are thought to aid in the removal of metabolic wastes, toxins, exudates, and cellular debris that occur during infection or oedema. In elderly patients with pneumonia LPT decreased hospital stay, length of intravenous antibiotics, and incidence of death when compared to conventional care. In animals, LPT has been reported to enhance the lymphatic and immune systems and facilitate the clearance pneumonia caused by Streptoccocus pneumoniae. The purpose of this study was to determine the number of LPT necessary to enhance the clearance of S. pneumoniae from the lungs and explore the mechanisms associated with this protection. MethodsRats were nasally infected with S. pneumoniae. Twenty-four hours after infection, rats were divided into control sham and LPT groups. For four consecutive days, the control group received no treatment or anaesthesia, the sham group received four min of light touch (under anaesthesia), and the LPT group received four min of LPT (under anaesthesia). On days 1, 3 and 4 post-infection, lungs were removed and measured for S. pneumoniae bacteria and the number of pulmonary leukocytes. Bronchoalveolar lavage fluid (BALF) was collected at day 4 post-infection and analysed for inflammatory mediators, antibacterial factors and alveolar macrophage function. ResultsThree applications of LPT were able to significantly (p < 0.05) reduce the numbers of pulmonary bacteria compared to control and sham. There were no significant differences in lung leukocytes between treatment groups at any time point, suggesting LPT does not enhance the concentration of pulmonary leukocytes. There were also no significant differences in the BALF concentrations of IL-1β, C-reactive protein, TNF-α, and MCP-1 between control, sham or LPT groups at day 4. This was not surprising, since these factors mediate pneumococcal clearance within the first 0–48 h of infection. Of importance, LPT increased the concentration of SP-D, IL-6, IL-17 and IL-12 in the BALF and enhanced the production of NO2- and IL-6 by alveolar macrophages compared to sham and control. ConclusionsWe have shown that three daily LPT enhance the clearance of pneumococcal bacteria, and the concentration of SP-D, IL-6, IL-12 and IL-17 in the BALF. During pneumococcal pneumonia, IL-12 and IL-17 enhance the entry of neutrophils into the lungs, SP-D enhances phagocytosis by neutrophils, and IL-6 delays neutrophil apoptosis and enhances neutrophil cytotoxic function. Alveolar macrophages from LPT treated rats produced more nitric oxide and IL-6 in vitro. Therefore, by enhancing the concentration of immune factors, LPT may preserve neutrophil-mediated clearance of pneumococcus. Collectively, our study supports the clinical use of LPT to treat pneumonia.