Avian macrophage metabolism

Dietert, R. R.; Ka, Golemboski

doi:10.1093/ps/77.7.990

Cited by 17 publications

(9 citation statements)

References 77 publications

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“…There is no evidence that constitutive enzymes synthesize LT from infused AA while COX was inhibited with meclofenamate ( Figure 4; meclofenamate + AA group). The capacity of activated chicken macrophage to produce significant quantities of LT has been questioned (Whelan et al, 1997;Dietert and Golemboski, 1998), but stimulated chicken thrombocytes clearly can synthesize LT (Hall et al, 2007). The vasoconstrictors responsible for increasing the PVR during the major peak PAP response to LPS remain to be determined.…”

Section: Discussionmentioning

confidence: 99%

Broiler pulmonary hypertensive responses during lipopolysaccharide-induced tolerance and cyclooxygenase inhibition

2009

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Bacterial lipopolysaccharide (LPS, endotoxin) triggers pulmonary hypertension (PH) characterized by an increase in pulmonary arterial pressure (PAP) that reaches a peak value within 20 to 25 min and then gradually subsides within 60 min. As the PAP subsides PH cannot be reinitiated, signifying the onset of a period of tolerance (refractoriness) to repeated LPS exposure. The present study was conducted to determine the duration of this tolerance, and to evaluate key mediators thought to contribute to LPS-mediated PH in broilers. Tolerance was shown to persist for 4 to 5 d after the initial exposure to LPS. In tolerant broilers supramaximal i.v. injections of LPS did not reinitiate PH, nor was a significant modulatory role for nitric oxide demonstrated. The pulmonary vasculature of tolerant broilers remains responsive to the thromboxane A(2) (TxA(2)) mimetic U44069, 5-hydroxytryptamine (5-HT, serotonin), and constitutive nitric oxide. Meclofenamate successfully blocked the conversion of arachidonic acid to vasoconstrictive eicosanoids such as TxA(2); nevertheless, meclofenamate failed to inhibit PH in response to LPS. Therefore, TxA(2) does not appear to be the primary vasoconstrictor involved in the PH response to LPS and neither does 5-HT. Broilers emerging from tolerance 5 d after the initial exposure to LPS exhibited interindividual variation in their PH responsiveness to a second LPS injection, ranging from zero response (individuals that remain fully tolerant) to large increases in PAP (post-tolerant individuals). Tolerance might be an important compensatory or protective mechanism for broilers whose pulmonary vascular capacity is marginally adequate under optimal conditions, and whose respiratory systems are chronically challenged with LPS in commercial production facilities. The key vasoconstrictors responsible for the PH elicited by LPS remain to be determined.

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Section: Discussionmentioning

confidence: 99%

Broiler pulmonary hypertensive responses during lipopolysaccharide-induced tolerance and cyclooxygenase inhibition

2009

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“…Callaghan MM, Lovis RM, Rammohan C, Lu Y, and Pope RM.Autocrine regulation of collagenase gene expression by TNF-alpha in U937 cells. J Leukoc Biol 59:[125][126][127][128][129][130][131][132] 1996. 78.…”

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confidence: 99%

Role of Monocytes in Atherogenesis

Østerud

Bjørklid

2003

Physiological Reviews

355

270

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This review focuses on the role of monocytes in the early phase of atherogenesis, before foam cell formation. An emerging consensus underscores the importance of the cellular inflammatory system in atherogenesis. Initiation of the process apparently hinges on accumulating low-density lipoproteins (LDL) undergoing oxidation and glycation, providing stimuli for the release of monocyte attracting chemokines and for the upregulation of endothelial adhesive molecules. These conditions favor monocyte transmigration to the intima, where chemically modified, aggregated, or proteoglycan- or antibody-complexed LDL may be endocytotically internalized via scavenger receptors present on the emergent macrophage surface. The differentiating monocytes in concert with T lymphocytes exert a modulating effect on lipoproteins. These events propagate a series of reactions entailing generation of lipid peroxides and expression of chemokines, adhesion molecules, cytokines, and growth factors, thereby sustaining an ongoing inflammatory process leading ultimately to lesion formation. New data emerging from studies using transgenic animals, notably mice, have provided novel insights into many of the cellular interactions and signaling mechanisms involving monocytes/macrophages in the atherogenic processes. A number of these studies, focusing on mechanisms for monocyte activation and the roles of adhesive molecules, chemokines, cytokines and growth factors, are addressed in this review.

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“…In the current situation of the poultry industry and looking towards the near future, the market scenraion requires reduction in the use of the antibiotics. This requires search for immune modulators that do not leave residues in the meat, promote good growth performance and works in adverse conditions so that the broilers can defend themselves against the pathogens (Dietert and Golemboski, 1998).…”

Section: Resultsmentioning

confidence: 99%