Lymphatic pump treatment mobilizes leukocytes from the gut associated lymphoid tissue into thoracic duct lymph

s from the 7 International Conference on Advances in Osteopathic Research (ICAOR 7), Bradenton, Florida, USA 5e7 September 2008 Lymphatic pump treatment mobilizes leukocytes from the gut associated lymphoid tissue into thoracic duct lymph Artur Schander , Melissa K. Bearden , Jamie B. Huff , Arthur Williams Jr., Scott T. Stoll , Jerry W. Simecka , Hollis H. King , H. Fred Downey , Lisa M. Hodge a,b a Department of Molecular Biology and Immunology, University of North Texas Health Science Center at Fort Worth, TX b National Osteopathic Research Center, University of North Texas Health Science Center at Fort Worth, TX c Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, TX Rhythmic compressions on the abdomen during lymphatic pump treatment (LPT) most likely compress the abdominal area, including the spleen and gastrointestinal mucosa, which may facilitate the release of leukocytes from these tissues into circulation. To determine the acute effects of LPT on canine intestinal lymph leukocytes, a catheter was inserted into the large intestinal lymph duct. In a separate set of experiments, the thoracic lymph duct was cannulated and 25-50% of the mesenteric lymph nodes (MLN) were fluorescently labeled in situwith carboxyfluorescein diacetate succinimidyl ester (CFSE). The abdominal incision was closed, and thoracic duct lymph was collected at baseline, during 4 min of LPT, and during 10 min following LPT. Total leukocytes in both thoracic duct and intestinal duct lymph were enumerated, and the number of neutrophils, macrophages, and lymphocytes was determined by differential cell staining. In addition, the percentage of CFSE labeled leukocytes (reflective of cells from the MLN), B cells, CD4+ T cells, CD8+ T cells, IgA and IgG antibody forming cells were measured by flow cytometry. Within the first 2 min of LPT, leukocytes are mobilized into intestinal and thoracic duct lymph circulation; however, larger increases in thoracic duct leukocytes appear later, in the last 2-4 min of treatment, and stay elevated during recovery while intestinal leukocyte numbers decrease. Flow cytometry and differential cell staining revealed that CD4+ T cells, CD8+ T cells, B cells and IgG antibody forming cells numbers were similarly increased during LPT. Interestingly, the baseline population of IgA forming cells was 6.10 1.80%, which increased to 8.75 2.62 % during LPT, suggesting that LPT acts preferentially on mucosal-derived cells. Furthermore, LPT increased the percentage of CFSE labeled leukocytes in the thoracic duct lymph from 15% to 22.6%, suggesting that the MLN are a tissue source that LPT can release leukocytes from. Collectively, these data suggest that LPT immediately releases leukocytes from the intestine that enter lymph circulation and reach the thoracic duct within 2-4 min. Furthermore, increased numbers of CFSE labeled leukocytes in thoracic duct lymph during LPT suggests that LPT can mobilize T and B cells from theMLN into the thoracic duct lymph. The gut associated lymphoid tissue (GALT) is an inductive tissue of antigen-specific leukocytes which migrate fromGALT into other mucosal associated tissues, such as the lung. Therefore, treatments, such as LPT, that specifically mobilize leukocytes from GALT may increase the numbers of leukocytes that are able to traffic into the lung during pulmonary infection. Funding for this project was provided by the National Institutes of Health (Grant No. U19 AT002023-01A1) and UNTHSC (Grant No. G67717). doi:10.1016/j.ijosm.2008.08.002