Osteopathic Lymphatic Pump Treatment as an Adjunctive Therapy to Protect Against Infection and Inflammation

The lymphatic system transports interstitial fluid from the tissue into circulation. Osteopathic physicians recognize the importance of the lymphatic system and have designed osteopathic manipulative techniques, including lymphatic pump treatment (LPT), to enhance the flow of lymph. LPT is used clinically by osteopathic physicians as an adjunctive therapy for the treatment of pneumonia, although its mechanism of protection is unknown. Recent studies have demonstrated LPT increased lymphatic flow and reduced the concentration of bacteria in the lungs of rats infected with Streptococcus pneumoniae. The combination of LPT and antibiotic further reduced the concentration of S. pneumoniae compared to antibiotics alone. The goal of these studies was to identify the mechanism(s) by which LPT protects the lung during infection. Enhancing lymph output using therapies such as LPT might redistribute protective lymph-borne factors and pharmaceuticals to the lung, providing additional protection against pneumonia. In the first aim we hypothesized that LPT would enhance the delivery of levofloxacin from the blood to the lung, which might accelerate the clearance of pulmonary bacteria. We discovered that LPT increased the concentration of antibiotic in the epithelial lining fluid over time. These results suggest LPT may aid during treatment of pneumonia by facilitating the delivery of antibiotics the lung. In previous studies, LPT protected rats against pneumonia without the need for antibiotics, suggesting there is another mechanism of protection offered by LPT. LPT mobilizes lymph-borne factors into circulation that may modulate pulmonary inflammation. Therefore, the second aim of these studies was to determine the biological effect of thoracic duct lymph mobilized during LPT on macrophage activity in vitro. Thoracic duct lymph suppressed the inflammatory response of macrophages and alveolar macrophages to lipopolysaccharide, lipoteichoic acid, and interferon-gamma. Importantly, lung immunopathology is associated with morbidity and mortality during pneumonia caused by S. pneumonia. Therefore, by mobilizing lymph into circulation, LPT may protect the lung by suppressing this immunopathologic response. In conclusion, these studies have elucidated mechanisms of protection offered by LPT and support its use as an adjunctive therapy for the treatment of pneumonia. Once these mechanisms are fully understood, LPT can be optimally applied to patients with pneumonia, which may substantially reduce morbidity, mortality and the cost of hospitalization.