Granulocyte Adherence in Pulmonary and Systemic Arterial Blood Samples from Patients with Adult Respiratory Distress Syndrome^1–4

Abstract

The accumulation of granulocytes in lung capillaries, caused by increased granulocyte adherence in response to circulating inflammatory mediators, is proposed as one mechanism of pulmonary vascular injury in the adult respiratory distress syndrome (ARDS). The adherence characteristics of granulocytes from humans with this syndrome have, however, not been described. We assayed the granulocyte adherence to nylon fiber columns using whole blood samples collected from the pulmonary artery of 14 patients within 24 h of satisfying criteria for ARDS. The mean value was 83% of that of normal subjects, and granulocyte adherence was less than or equal to control in samples from 10 of 14 patients. Eight of 12 plasma samples, including 7 of 10 from patients with decreased or normal whole blood granulocyte adherence, contained an activity that increased the adherence of granulocytes isolated from normal subjects. These data suggest that granulocytes may become desensitized to a circulating adherence-promoting mediator or that granulocytes with different functional characteristics circulate in some patients with ARDS. Granulocyte adherence varied directly with the circulating platelet number, indicating that adherence may be influenced by cell-cell interactions as well as by humoral mediators. The granulocyte adherence was a mean of 75% of control samples in samples from 3 patients with increased lung uptake of indium-labeled leukocytes, suggesting that granulocyte accumulation in the lung can occur in the absence of markedly enhanced adherence of circulating cells. These data also suggest that alterations in lung endothelial cells, or the local elaboration of inflammatory mediators, may be important determinants of granulocyte accumulation in the pulmonary microvasculature in established ARDS.

Thrombin stimulates the adherence of neutrophils to human endothelial cells in vitro.

“…The observations are important because the mechanisms by which chemotactic factors and humoral inflammatory mediators promote PMN adherence to endothelium are not clearly defined. Although under some conditions chemotactic factors such as fMLP, LTB4, and C5a fragments may enhance neutrophil adherence by acting on the endothelium (48)(49)(50), each of these mediators also directly stimulates the adhesiveness of the neutrophils (20,24,25,48,49,51). A recent report suggests that a direct action on the neutrophils is the dominant effect of C5a, C5a desarg, and fMLP (51).…”

“…Neutrophils were isolated from venous blood using dextran sedimentation and Ficoll-Hypaque gradients as described (20). A group of healthy subjects of various ages and both sexes served as PMN donors.…”

“…'In-oxine or tropolonate, 98% or more of the neutrophils excluded Trypan Blue. Their functional status was similar to that of unlabeled PMNs since (a) they spontaneously adhered to nylon fiber columns and the basal adherence could be increased by increasing the weight of nylon fiber, a functional assay of viability (23), (b) adherence to the columns could be increased by incubating the labeled neutrophils with fMLP, LTB4, or C5a desarg, which are known agonists of neutrophil adherence (20,24,25) Adherence oflabeled neutrophils to endothelial cell monolayers. Endothelial monolayers that had been tightly confluent (19) for a minimum of 24 h before use were washed with HBSS (370C) after removal of the culture medium.…”

“…A modification of a previously reported method (20) was used. Columns con-taining nylon fiber were made as described and warmed to 370C.…”

Distinct Ligand-dependent Roles for p38 MAPK in Priming and Activation of the Neutrophil NADPH Oxidase

“…Moore, Silliman, and others (52)(53)(54) have shown that PAF is a primary agent responsible for neutrophil priming in human trauma victims. In contrast, LPS and TNF␣ are the likely priming agents in acute pancreatitis (55,56), as well as in many patients with sepsis (57)(58)(59)(60)(61), and these agents have been directly implicated in causing acute lung injury (62)(63)(64)(65) and ischemia-induced acute renal failure (66).…”