Lymphatic pump treatment enhances immunity and reduces pulmonary disease during experimental pneumonia infection

Abstract

Clinical studies have shown that patients given osteopathic lymphatic pump treatment (LPT) during pneumonia have enhanced clearance of the tracheobronchial tissues, shorter duration of cough, and shorter duration of total and intravenous antibiotic treatment and hospitalization. These studies suggest that LPT may reduce pulmonary infection by enhancing immunity; however, the exact mechanisms responsible for the clinical benefits of LPT have not been identified. The purpose of this study was to determine if LPT would enhance immunity and reduce pulmonary disease during chronic pneumonia. To determine if a single LPT would increase blood leukocytes, samples were collected from the jugular vein at baseline, immediately following LPT (n¼7) or sham (n¼7), and at 10, 20, 30 45, and 60 minutes post LPT or sham and analyzed for leukocyte concentrations. Consistent with reports in humans, LPT released approximately 4,000,000 more leukocytes into blood circulation 45 minutes after treatment compared to sham (p<0.01). Differential analysis revealed these were primarily lymphocytes. In a separate set of experiments, rats were intranasally infected with 5 x 10 5 colony forming units of Mycoplasma pulmonis. Twenty-four hours following infection, rats received either Sham (n¼8) or LPT (n¼9), under anesthesia, daily for days 1-4, and 7-10 post infection. Fourteen days following infection rats were euthanized, lungs were removed and analyzed for gross lesions and bacterial numbers, and blood samples were analyzed for leukocyte concentrations. During M. pulmonis infection, LPT reduced pulmonary bacterial numbers 4-fold, and lung lesions 13% compared to sham (p<0.05). Furthermore, LPT increased blood leukocyte numbers compared to sham (p<0.05). Specifically, LPT released approximately 1, 000,000 more lymphocytes and 80,000 more monocytes into blood circulation compared to sham. Collectively, these data suggest that during pulmonary infection, LPT increases circulating leukocytes that may traffic into the lung and kill bacteria, thereby reducing lung lesions. Ongoing and future studies will examine if LPT enhances leukocyte activation and recruitment into the lung. These data are essential to identifying the mechanisms by which LPT enhances immunity and clearance of pneumonia, and will provide scientific support for the clinical use of LPT. Funding for this project was provided by the American Osteopathic Association (Grant No. 06-11-547).