Die Rolle der polymorphkernigen neutrophilen Leukozyten in der Pathogenese des akuten Lungenversagens (ARDS)

Abstract

Polymorphonuclear leukocytes (PM-NL) constitute the first line of defence in the protection of the host from invading microorganisms. PMNL also contribute to the removal of cellular debris from necrotic tissues during reparative processes. For these purposes PMNL are armed with highly efficient bactericidal mechanisms which, under certain pathophysiological conditions, can be turned against the host himself. A vast body of evidence indicates that PMNL are able to cause lung injury which may be followed by the development of acute respiratory distress syndrome (ARDS). Accordingly, in patients with ARDS blood concentrations of inflammatory activators of PMNL are elevated, cytotoxic mechanisms of PMNL are enhanced and sequestration of these cells has been demonstrated to be inversely proportional to gas exchange. The manifestation of ARDS in leukopenic patients, however, indicates the development of this clinical syndrome independently of the presence of PMNL. The ability to differentiate between PMNL-dependent and PMNL-independent pathways in the pathogenesis of this syndrome is not only of theoretical interest but also of therapeutic significance. Since the patient's systemic inflammatory response may vary according to the stage and type of the underlying disease, an exact qualitative and quantitative analysis of PMNL functions may provide the rationale for new anti-inflammatory drug regimens aimed at modifying the host's response without increasing the risk of infection.

Pentoxifylline improves bacterial clearance during hemorrhage and endotoxemia

“…Increased resistance against sepsis or endotoxemia was observed in mice and rats, and, in recent studies, in human patients [27,28] . PTX inhibits the production of oxygen radicals of polymorphonuclear neutrophils [11,29,30] and their adherence to endothelial cells by inhibiting the expression of adhesion molecules on the cell surface of polymorphonuclear neutrophils [13,31,32] ; it also reduces the production of inflammatory cytokines, in particular of TNF [7,33,34] , and prevents platelet aggregation [35,36] . Moreover, PTX improves perfusion of the microvascular bed and tissue oxygenation [37,38] .…”

Molecular Aspects of Regeneration Mechanisms in Holothurians

“…ROS is known to play a significant role in phagocytosis. In vertebrates, generation of ROS during phagocytosis is balanced with a high antioxidant enzyme activity of phagocytes [124]. Thus, one of the indicators of holothurian immune system's functioning is the activity of coelomocyte antioxidant enzymes [125].…”

Leukocyte Activation by means of Intraoperative Blood Salvage

“…Polymorphonuclear leukocytes (PMNL) are the first line of defense against invading microorganisms, but excess activation of PMNL is also regarded as the cause of acute lung failure [2]. PMNL priming potentiates the PMNL response to an activating stimulus, which results in pronounced and demonstrable in vitro and in vivo endothelial damage, while PMNL that are not activated to the 'priming threshold' cause only minimal changes in the endothelium [3].…”