Soluble Adhesion Molecules During Ex Vivo Lung Perfusion Are Associated With Posttransplant Primary Graft Dysfunction.

Ex vivo lung perfusion (EVLP) enables assessment of marginal donor lungs for transplantation. We aimed to discover biomarkers in EVLP perfusate that could predict development of primary graft dysfunction (PGD). From September 2008 to August 2013, 100 clinical EVLPs were performed. Eleven patients developed PGD grade 3 within 72 h after transplant. The non-PGD group consisted of 34 patients without PGD grade 3. Nonbilateral lung transplants or transplant after extracorporeal life support were excluded from analyses. Soluble intercellular adhesion molecule 1 (sICAM-1), soluble VCAM-1 (sVCAM-1), and soluble E selectin (sE-selectin) levels, as markers of endothelial activation, were measured in the perfusate of EVLP by enzyme-linked immunosorbent assay and were correlated with clinical outcome. Levels of sICAM-1 at 1 h and sVCAM-1 at 1 and 4 h were significantly higher in the PGD group compared with the non-PGD group. The sE selectin levels were not statistically different between the study groups. Higher levels of sVCAM-1 at 1 and 4 h were statistically significantly associated with PGD either alone or after adjustment for other PGD risk factors. These adhesion molecules may help identify donor lungs at higher risk of PGD during EVLP.

Distinct expression patterns of alveolar "alarmins" in subtypes of chronic lung allograft dysfunction.

The long-term success of lung transplantation is limited by chronic lung allograft dysfunction (CLAD). The purpose of this study was to investigate the alveolar alarmin profiles in CLAD subtypes, restrictive allograft syndrome (RAS) and bronchiolitis obliterans syndrome (BOS). Bronchoalveolar lavage (BAL) samples were collected from 53 recipients who underwent double lung or heart-lung transplantation, including patients with RAS (n = 10), BOS (n = 18) and No CLAD (n = 25). Protein levels of alarmins such as S100A8, S100A9, S100A8/A9, S100A12, S100P, high-mobility group box 1 (HMGB1) and soluble receptor for advanced glycation end products (sRAGE) in BAL fluid were measured. RAS and BOS showed higher expressions of S100A8, S100A8/A9 and S100A12 compared with No CLAD (p < 0.0001, p < 0.0001, p < 0.0001 in RAS vs. No CLAD, p = 0.0006, p = 0.0044, p = 0.0086 in BOS vs. No CLAD, respectively). Moreover, RAS showed greater up-regulation of S100A9, S100A8/A9, S100A12, S100P and HMGB1 compared with BOS (p = 0.0094, p = 0.038, p = 0.041, p = 0.035 and p = 0.010, respectively). sRAGE did not show significant difference among the three groups (p = 0.174). Our results demonstrate distinct expression patterns of alveolar alarmins in RAS and BOS, suggesting that RAS and BOS may represent biologically different subtypes. Further refinements in biologic profiling will lead to a better understanding of CLAD.

Okadaic acid-induced actin assembly in neutrophils: role of protein phosphatases.

Activation of neutrophils results in morphological and functional alterations including changes in cell shape and initiation of motile behavior that depend on assembly and reorganization of the actin cytoskeleton. Phosphoproteins are thought to be key intermediates in the regulation of cytoskeletal alterations and whereas much attention has been directed at the role of protein kinases, relatively little information is available on the importance of phosphatases. To elucidate the role of protein phosphatases, we studied the effects of the phosphatase inhibitors okadaic acid and calyculin A on the actin cytoskeleton of human neutrophils. Exposure of cells to okadaic acid resulted in assembly and spatial redistribution of actin, which peaked at 25 min and returned to baseline levels by 45 min, as assessed by flow cytometric analysis of NBD-phallacidin stained cells and confocal fluorescence microscopy, respectively. These effects correlated with an increase in protein phosphorylation, determined by incorporation of 32P into cellular proteins using SDS-PAGE and autoradiography. Similar but more rapid responses were observed in electropermeabilized cells treated with okadaic acid or calyculin A. The dose dependence of these effects was compatible with a role for phosphatase type 1 as the target enzyme. These findings also suggested the presence of constitutively active protein kinases capable of effecting actin polymerization. Phosphorylation of myosin light chain (MLC) has been postulated to promote actin assembly, but myosin light chain kinase (MLCK) appeared not to be involved because: (1) the effect of okadaic acid was not inhibited by the MLCK inhibitor KT5926 and (2) in permeabilized cells suspended in medium with free calcium [Ca2+] < 10 nM (conditions under which MLCK is inactive), the effect of okadaic acid persisted. The role of phosphatases in stimulus-induced actin assembly was assessed in cells preincubated with okadaic acid for 45 min, after F-actin levels had returned to baseline. Under these conditions, okadaic acid completely abrogated actin assembly induced by phorbol myristate acetate, platelet activating factor, and leukotriene B4, whereas the effects of the chemotactic peptide fMLP and opsonized zymosan (OpZ) were unaffected. We conclude that serine and threonine phosphatases exert a tonic negative influence on actin assembly and organization. Furthermore, divergent pathways seem to mediate the response to lipidic stimuli, on one hand, and fMLP and OpZ, on the other, as evidenced by the differential susceptibility to inhibition by okadaic acid.