antileukinate and Respiratory-Distress-Syndrome

High mobility group box 1 (HMGB1) protein, a late mediator of lethality in sepsis, can induce acute inflammatory lung injury. Here, we identify the critical role of alpha-chemokine receptors in the HMGB1-induced inflammatory injury and show that alpha-chemokine receptor inhibition increases survival in sepsis, in a clinically relevant time frame. Intratracheal instillation of recombinant HMGB1 induces a neutrophilic leukocytosis, preceded by alveolar accumulation of the alpha-chemokine macrophage inflammatory protein-2 and accompanied by injury and increased inflammatory potential within the air spaces. To investigate the role of alpha-chemokine receptors in the injury, we instilled recombinant HMGB1 (0.5 microg) directly into the lungs and administered a subcutaneous alpha-chemokine receptor inhibitor, Antileukinate (200 microg). alpha-Chemokine receptor blockade reduced HMGB1-induced inflammatory injury (neutrophils: 2.9 +/- 3.2 vs. 8.1 +/- 2.4 x 10(4) cells; total protein: 120 +/- 48 vs. 311 +/- 129 microg/ml; reactive nitrogen species: 2.3 +/- 0.3 vs. 3.5 +/- 1.3 microM; and macrophage migration inhibitory factor: 6.4 +/- 4.2 vs. 37.4 +/- 15.9 ng/ml) within the bronchoalveolar lavage fluid, indicating that HMGB1-induced inflammation and injury are alpha-chemokine mediated. Because HMGB1 can mediate late septic lethality, we administered Antileukinate to septic mice and observed increased survival (from 58% in controls to 89%) even when the inhibitor treatment was initiated 24 h after the induction of sepsis. These data demonstrate that alpha-chemokine receptor inhibition can reduce HMGB1-induced lung injury and lethality in established sepsis and may provide a novel treatment in this devastating disease.

Topics: Animals; Chemokine CXCL2; Chemokines; Chemokines, CXC; Female; HMGB1 Protein; Mice; Mice, Inbred BALB C; Neutrophils; Oligopeptides; Pneumonia; Pulmonary Alveoli; Receptors, Chemokine; Respiratory Distress Syndrome; Sepsis

Polymorphonuclear neutrophil (PMN) extravasation/sequestration in the lung and a dysregulated inflammatory response characterize the pathogenesis of acute lung injury (ALI). Previously, we have shown that hemorrhage (Hem) serves to prime PMN such that subsequent septic challenge [cecal ligation and puncture (CLP)] produces a pathological, inflammatory response and consequent lung injury in mice. Keratinocyte-derived chemokine (KC) and macrophage inflammatory protein-2 (MIP-2) are murine CXC chemokines found elevated in the lungs and plasma following Hem/CLP and have been reported by others to share a common receptor (CXCR2). Based on these data, we hypothesize that blockade of CXCR2 immediately following Hem would suppress KC and MIP-2 priming of PMN, thereby reducing the inflammatory injury observed following CLP. To assess this, Hem mice (90 min at 35+/-5 mmHg) were randomized to receive 0, 0.4, or 1 mg antileukinate (a hexapeptide inhibitor of CXCRs) in 100 microl phosphate-bufferd saline (PBS)/mouse subcutaneously, immediately following resuscitation (Ringer's lactate-4x drawn blood volume). Twenty-four hours post-Hem, mice were subjected to CLP and killed 24 h later. The results show that blockade of CXCR2 significantly (P<0.05, Tukey's test) reduced PMN influx, lung protein leak, and lung-tissue content of interleukin (IL)-6, KC, and MIP-2 and increased tissue IL-10 levels. Plasma IL-6 was significantly decreased, and IL-10 levels increased in a dose-dependent manner compared with PBS-treated mice. A differential effect was observed in plasma levels of KC and MIP-2. KC showed a significant reduction at the 0.4 mg antileukinate dose. In contrast, plasma MIP-2 was significantly elevated at both doses compared with the PBS-treated controls. Together, these data demonstrate that blockade of CXCR2 signaling attenuates shock-induced priming and ALI observed following Hem and subsequent septic challenge in mice.

Topics: Animals; Cecum; Chemokines; Disease Models, Animal; Hemorrhage; Immunohistochemistry; Inflammation; Ligation; Mice; Neutrophil Infiltration; Neutrophils; Oligopeptides; Receptors, Interleukin-8B; Respiratory Distress Syndrome; Sepsis

A hexapeptide, Ac-RRWWCR-NH(2) (Antileukinate), has been reported to be a potent inhibitor of CXC-chemokine receptor. However, the in vivo anti-inflammatory activity of this agent has not been tested except in a rabbit skin edema model. This study was undertaken to investigate the effect of subcutaneously administered Antileukinate on experimental bleomycin-induced acute lung injury in mice, in which CXC-chemokines have been reported to be involved. Lung injury was assessed on the basis of histopathology, the number of total cells, the percentage of neutrophils, and protein concentration in the bronchoalveolar lavage (BAL) fluid, and the wet lung weight at 7 days after intratracheal instillation of bleomycin. Histopathological studies revealed that treatment with Antileukinate markedly suppressed inflammatory cell infiltration and interstitial lung edema. The neutrophil counts in the BAL fluid were significantly decreased in the Antileukinate-treated group. The suppression of pulmonary edema was further confirmed by the reduction of wet lung weight and total protein concentration in the BAL fluid. These findings suggest that Antileukinate is able to inhibit acute lung injury by suppressing neutrophil mobilization induced by CXC-chemokines.

Topics: Animals; Bleomycin; Bronchoalveolar Lavage Fluid; Chemokines, CXC; Male; Mice; Mice, Inbred ICR; Neutrophils; Oligopeptides; Receptors, Chemokine; Respiratory Distress Syndrome