Macrophage Polarization And Nitric Oxide Mechanisms In Lymphatic Dysfunction In A Rat Model Of Metabolic Syndrome

Metabolic syndrome (MetSyn) is the clustering of multiple metabolic disorders that further increase the risk for cardiovascular disease and has been recently linked to poor lymphatic function. The lymphatic system plays a crucial role in maintaining oncotic balance and returning excess fluid and macromolecules back to the blood circulation. In this dissertation we addressed the role of macrophage polarization and nitric oxide mechanisms in lymphatic dysfunction in a rat model of MetSyn. We hypothesized that mesenteric lymphatic vessel dysfunction would be associated with a polarization switch of resident macrophages after induction of peritonitis or metabolic syndrome. We used an intra-peritoneal injection of lipopolysaccharide (LPS) to simulate peritonitis in the rat and a seven-week high fructose-feeding regime to induce the MetSyn. We distinguished macrophage polarization and recruitment to the lymphatic collecting vessels using immunofluorescence and a combination of CD163, CD206, and major histocompatibility complex II (MHCII) expression. We determined the intrinsic mesenteric lymphatic contractility using the isolated mesenteric lymphatic vessel isobaric preparation. LPS-induced peritonitis increased the macrophage accumulation two fold and increased both CD163+CD206+ and CD163-CD206+ cell populations and had severely impaired lymphatic contractility. We also found evidence for a phenotype switch from CD163+MHCII- M2 macrophages to a M1 skewed CD163+MHCII+ phenotype in the MetSyn rats and impaired lymphatic contractility. Additionally, cultured lymphatic endothelial and muscle cells were found to express macrophage maturation and expansion markers in response to LPS stimulation. We also examined the role of nitric oxide in the contractile regulation of lymphatic thoracic ducts isolated from MetSyn rats. We found a reduced flow-dependent inhibition of contractility in metabolic syndrome thoracic ducts despite a normal response to the exogenous nitric oxide donor S-nitro-N-acetylpenicillamine (SNAP). The reactive oxygen species scavenging agent 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL) did not restore flow sensitivity, however control vessels treated with the nitric oxide synthase inhibitor L-NG-nitro arginine methyl ester (LNAME) had comparable flow inhibition to MetSyn thoracic ducts. Western blots of thoracic ducts revealed a 60% reduction in the expression of eNOS, which can explain the loss of shear sensitivity. Thus, this study demonstrates the mechanisms that underlie lymphatic dysfunction in the MetSyn

Developmental progression of lymphatic valve morphology and function

Introduction: The bileaflet valves found in collecting lymphatic vessels and some veins are essential for maintaining a unidirectional flow, which is important for lymphatic and venous function. Under an adverse pressure gradient, the two leaflets tightly overlap to prevent backflow. Valves are proposed to share four main stages of development, based on images obtained from randomly oriented valves in fixed mouse embryos, with the best structural views obtained from larger venous valves. It is not known at what stage lymphatic valves (LVs) become functional (e.g., able to oppose backflow), although a requirement for stage 4 is presumed.Methods: To gain an insight into this sequence of events for LVs, we used Prox1CreERT2:Foxo1fl/fl mice and Foxc2CreERT2:Foxo1fl/fl mouse models, in which deletion of the valve repressor factor Foxo1 promotes the development of new LVs in adult lymphatic vessels. Both strains also contained a Prox1eGFP reporter to image the lymphatic endothelium. Mesenteric collecting lymphatic vessels were dissected, cannulated, and pressurized for ex vivo tests of valve function. LVs at various stages (1–4 and intermediate) were identified in multi-valve segments, which were subsequently shortened to perform the backleak test on single valves. The GFP signal was then imaged at high magnification using a confocal microscope. Z-stack reconstructions enabled 1:1 comparisons of LV morphology with a quantitative measurement of back leak.Results: As expected, LVs of stages 1–3 were completely leaky in response to outflow pressure elevation. Stage 4 valves were generally not leaky, but valve integrity depended on the Cre line used to induce new valve formation. A high percentage of valves at leaflet an intermediate stage (3.5), in which there was an insertion of a second commissure, but without proper luminal alignment, effectively resisted back leak when the outflow pressure was increased.Discussion: Our findings represent the first 3D images of developing lymphatic valves and indicate that valves become competent between stages 3 and 4 of development

Novel Characterization of Lymphatic Valve Formation during Corneal Inflammation

Lymphatic research has progressed rapidly in recent years. Though lymphatic dysfunction has been found in a wide array of disorders from transplant rejection to cancer metastasis, to date, there is still little effective treatment for lymphatic diseases. The cornea offers an optimal site for lymphatic research due to its accessible location, transparent nature, and lymphatic-free but inducible features. However, it still remains unknown whether lymphatic valves exist in newly formed lymphatic vessels in the cornea, and how this relates to an inflammatory response. In this study, we provide the first evidence showing that lymphatic valves were formed in mouse cornea during suture-induced inflammation with the up-regulation of integrin alpha 9. The number of corneal valves increased with the progression of inflammatory lymphangiogenesis. Moreover, we have detected lymphatic valves at various developmental stages, from incomplete to more developed ones. In addition to defining the average diameter of lymphatic vessels equipped with lymphatic valves, we also report that lymphatic valves were more often located near the branching points. Taken together, these novel findings not only provide new insights into corneal lymphatic formation and maturation, but also identify a new model for future investigation on lymphatic valve formation and possibly therapeutic intervention

Influence of acetylsalicylic acid on hematotoxicity of benzene

Objectives: The aim of the study was to evaluate the influence of acetylsalicylic acid (ASA) on benzene hematotoxicity in rats. Materials and Methods: The study was carried out on rats exposed for 2, 4 and 8 weeks to benzene vapour at a conentration of 1.5 or 4.5 mmol/m3 of air (5 days per week, 6 hours per day) alone or together with ASA at the doses of 5, 150 or 300 mg/kg body weight (per os). Results: Benzene at a concentration of 4.5 mmol/m3 caused a slight lymphopenia, granulocytosis and reticulocytosis in blood. In bone marrow traits of megaloblastic renewal, presence of undifferentiated cells and giant forms of granulocytes as well as an increase in myeloperoxidase and decrease in chloroacetate esterase activity and lipids content were noted. ASA (150 and 300 mg/kg b.w.) influenced some of hematological parameters, altered by benzene intoxication. ASA limited the solvent-induced alteration in blood reticulocyte count and in the case of bone marrow in the erythroblasts count. Traits of megaloblastic renewal in bone marrow were less pronounced. Besides, higher activity of myeloperoxidase and the decrease in the level of lipids in granulocytes were noted. Conclusion: Our results suggest that ASA limited the benzene-induced hematotoxicity

Cardiac lymphatics in health and disease

The lymphatic vasculature, which accompanies the blood vasculature in most organs, is indispensable in the maintenance of tissue fluid homeostasis, immune cell trafficking, and nutritional lipid uptake and transport, as well as in reverse cholesterol transport. In this Review, we discuss the physiological role of the lymphatic system in the heart in the maintenance of cardiac health and describe alterations in lymphatic structure and function that occur in cardiovascular pathology, including atherosclerosis and myocardial infarction. We also briefly discuss the role that immune cells might have in the regulation of lymphatic growth (lymphangiogenesis) and function. Finally, we provide examples of how the cardiac lymphatics can be targeted therapeutically to restore lymphatic drainage in the heart to limit myocardial oedema and chronic inflammation.Peer reviewe

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

Wplyw zageszczenia lanu na zmiany konkurencyjnosci jeczmienia jarego i owsa gluchego [Avena fatua L.] w zakresie pobierania mikroelementow

Doświadczenie jednoczynnikowe realizowano w latach 2000-2001. Oceniono zmiany w pobieraniu mikroelementów przez jęczmień jary i owies głuchy (Avena fatua L.) rosnących osobno i razem w warunkach zróżnicowanej obsady roślin. Owies głuchy i jęczmień rosły na poletkach w stosunku 1 : 0, 1 : 1 oraz 0 : 1 w przeliczeniu na 100, 300 i 500 roślin na 1 m². Zawartość i pobranie Cu, Zn, Mn i Fe przez jęczmień jary i owies głuchy zależały od zagęszczenia łanu oraz obecności drugiego gatunku. Pozbawiony konkurencji owies głuchy pobierał więcej niż jęczmień jary Zn, Mn i Fe, a mniej Cu, przy czym pobranie mikroelementów rosło w miarę zwiększania liczby chwastów. W obecności jęczmienia, szczególnie w zagęszczonym łanie, konkurencyjność chwastu została wyraźnie ograniczona. Jęczmień jary zachwaszczony owsem głuchym wykazuje większe zdolności konkurencyjne w pobieraniu mikroelementów niż towarzyszący mu owies głuchy.One-factorial microplot experiment was carried out in years 2000-2001 to assess the changes in uptake of microelements by spring barley and wild oats (Avena fatua) grown separately and together under conditions of differentiated density. Wild oats and barley were grown on plots at ratios of 1 : 0, 1 : 1 and 0 : 1, as converted into 100, 300, 500 plants per 1 m². The content and uptake of Cu, Zn, Mn and Fe by spring barley and wild oats depended on the number of plants as well as on the presence of other species. Without any competition wild oats was uptaking more Zn, Mn and Fe and less Cu as compared to spring barley. The uptake of microelements was increasing as the number of weeds per lm2 was increased. At the presence of barley, especially in concentrated crop stand, the competitiveness of weed was visibly reduced. The competitive abilities of microelements uptake of spring barley infested by wild oats were better than the competitive abilities of the accompanied weed