Bronchoalveolar Lavage TNF-alpha Research Articles

Interleukin-6 neutralization alleviates acute exacerbation-like disease in a model of cigarette smoke-induced pulmonary inflammation

Increased systemic and pulmonary levels of interleukin (IL)-6 have been associated with the severity of acute exacerbations and accelerated decline of lung function in COPD patients. The demonstration that IL-6 plays a pivotal role in AE-related pulmonary symptoms and therefore represents a therapeutic target for the treatment of COPD, remains elusive. We used a murine model where C57BL/6 female mice are exposed to cigarette smoke (CS) twice daily through a nose-only system, while being punctually challenged intranasally with poly I:C, a synthetic ligand for Toll Like Receptor-3 (TLR3). This protocol recapitulates several aspects of pulmonary inflammation as seen in acute exacerbations of COPD, including prominent airway neutrophilia as well as increased levels of type I interferon, GM-CSF, IL-6, KC, MIP-1 alpha, RANTES, and TNF-alpha in bronchoalveolar lavage (BAL) samples. Using this model, IL-6 deficient mice showed a susceptibility to CS-induced pulmonary inflammation that, overall, was comparable to that found with wild-type (WT) control mice. In contrast, using the same model with WT mice treated intraperitoneally with IL-6 neutralizing antibodies (rat IgG1, clone MP5-20F3, 25 mg/kg thrice weekly) diminished blood counts of lymphocytes (p=0.0070) and monocytes (p=0.0091), while this treatment also depleted BAL levels of IL-6 (p=0.0002) and reduced BAL levels of KC (p=0.0220). Total BAL cellularity was found to be largely decreased (p<0.0001) as well as BAL numbers of neutrophils (p=0.0031), lymphocytes (p<0.0001) and macrophages (p<0.0001), while inflammatory infiltrates seemed reduced in lung tissue sections from treated mice. Our results show that the neutralization of IL-6 largely abrogates pulmonary inflammation in CS-exposed mice, and therefore indicate that IL-6 may be a valid therapeutic target for the treatment of COPD, in particular in episodes of acute exacerbation.

Endotoxin induces late increase in the production of pulmonary proinflammatory cytokines in murine lupus-like pristane-primed modelp

Lupus-like syndrome is characterized by multiple organ injuries including lungs and kidneys. Endotoxin induces a transiently intent systemic inflammatory response and indirectly transient acute lung injury in normal condition. However, whether endotoxin may trigger the persistent development of lung injury in chronic, inflammatory lupus-like syndrome compared with normal condition remains unclear. We examined the pulmonary vascular permeability and production of proinflammatory cytokines, such as TNF-alpha, IL-6, IL-10 and IFN-gamma, which play prominent roles in the pathogenesis of lupus-like tissue injury, 6 h and 72 h after i.p. lipopolysaccharide (LPS; endotoxin) injection in pristane-primed chronic inflammation ICR mice characterized by a lupus-like syndrome. These results demonstrated that levels of serum IL-6, IL-10 and IFN-gamma and bronchoalveolar lavage (BAL) IL-6 and IFN-gamma were remarkably increased 6 h in LPS-exposed pristane-primed mice compared with pristane-primed controls, while pulmonary vascular permeability and levels of serum and BAL TNF-alpha were not. And levels of BAL TNF-alpha, IL-6 and IL-10 were significantly enhanced 72 h in LPS-exposed pristane-primed mice compared with pristane-primed controls. Also, LPS significantly induced the increased in vitro production of TNF-alpha, IL-6 and IL-10 by lung cells obtained from LPS-exposed pristane-primed mice compared with LPS-exposed normal mice. Our findings indicate that LPS may trigger persistent progression of lung injury through late overproduction of BAL TNF-alpha, IL-6, and IL-10 in lupus-like chronic inflammation syndrome compared with normal condition.

Effect of the p38 kinase inhibitor, SB 203580, on allergic airway inflammation in the rat.

Tumour necrosis factor-alpha (TNF-alpha) and interleukin 1beta (IL-1beta) have been implicated in the pathogenesis of asthma. The p38 kinase inhibitor, SB 203580 inhibits TNF-alpha and IL-1beta production in vitro and in vivo. In this study the effect of SB 203580 on allergen-induced airway TNF-alpha production and inflammatory cell recruitment was investigated in sensitized Brown Norway rats. The allergen-induced increase in bronchoalveolar lavage (BAL) TNF-alpha was inhibited by SB 203580 at every dose tested (10 - 100 mg kg(-1), p.o.). In contrast, neither ovalbumin-induced eosinophilia or neutrophilia were inhibited by SB 203580 (10 - 100 mg kg(-1), p.o.). In conclusion, SB 203580 inhibits BAL TNF-alpha production by 95% without inhibiting either antigen-induced airway eosinophilia or neutrophilia. This data suggests that either the residual TNF-alpha is sufficient to drive allergen-induced inflammatory cell recruitment into the lung or that TNF-alpha is not involved in allergen-induced inflammatory cell recruitment.

Anti-inflammatory properties of ebselen in a model of sephadex-induced lung inflammation.

Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one), is a seleno-organic compound which protects tissues against oxidative stress. Furthermore, recent data has suggested that this compound possesses a range of anti-inflammatory properties. In this study the authors have investigated the effects of ebselen on Sephadex-induced lung oedema and bronchoalveolar lavage (BAL) tumour necrosis factor (TNF)-alpha and endothelin(ET)-1 levels in rats. Sephadex administration induced lung oedema which was accompanied by an increase in BAL TNF-alpha and ET-1 levels. Ebselen administration (1-30 mg x kg(-1), i.p. at 0, 4 and 12 h post Sephadex) significantly inhibited lung oedema (dose that produced 50% of the maximum inhibition of lung oedema 4.6 mg x kg(-1)) and BAL TNF-alpha levels in a dose-related manner with no effect on ET-1 levels. These data suggest that ebselen may be a useful therapy in lung pathologies in which bronchiolar inflammation is a feature.

Intratracheal instillation versus intratracheal inhalation: influence of cytokines on inflammatory response.

Our laboratory has developed a method of particle exposure whereby anesthetized rats intratracheally inhale, at a regulated breathing rate and pressure, an aerosolized test material. This method is capable of delivering considerable doses in a short time period and, unlike the commonly used method of intratracheal instillation, does so with an even particle distribution throughout the lung. Early studies comparing the response of male Fischer 344 rats exposed to TiO2 particles of two differing primary particle sizes showed that at similar particle doses animals exposed by the two methods showed differences in response, as measured by bronchoalveolar lavage (BAL) parameters. Building on this, we sought to study the roles that macrophage inflammatory protein-2 (MIP-2) and tumor necrosis factor alpha (TNF-alpha), two cytokines thought to have proinflammatory roles in the lung, may play in the differences observed. Increases in MIP-2 protein levels in the lavaged cells, but not the supernatant, were observed in those groups where increased polymorphonuclear cells (PMN) in the lung lavage were found, but not in those where no increase in PMN levels was observed. BAL TNF-alpha levels, measured by enzyme-linked immunosorbent assay, showed no apparent correlation with cellular or biochemical BAL parameters for either particle size or dosing method. Increases in immunocytochemical staining for TNF-alpha, compared to unexposed controls, were observed in several particle-exposed groups. Thus, it appears that increased BAL MIP-2 protein levels, but not TNF-alpha, correlate well with the inflammatory response, as measured by PMN numbers in lavaged cells, for both exposure systems.

Glucocorticoid effects in an endotoxin-induced rat pulmonary inflammation model: differential effects on neutrophil influx, integrin expression, and inflammatory mediators.

To understand the basis for the refractory nature of acute respiratory distress syndrome (ARDS) to glucocorticoids, the effects of dexamethasone pretreatment (DEX, 2 mg/kg, intraperitoneally) on the kinetics of airway tumor necrosis factor-alpha (TNF alpha) and macrophage inflammatory protein 2 (MIP-2) production, and polymorphonuclear leukocyte (PMN) influx after intratracheal lipopolysaccharide (LPS) (1 mg/kg) in rats were investigated. In the absence of exogenous glucocorticoids, TNF alpha and MIP-2 levels in bronchoalveolar lavage (BAL) fluid peaked at 21 and 300 ng, respectively, by 3 h. DEX pretreatment resulted in a 74% reduction in BAL TNF alpha, yet MIP-2 accumulation was unchanged. In addition, DEX reduced PMN influx at 5 h by 58.4% to 4.1 +/- 0.7 x 10(6) PMN (n = 5). DEX, however, did not mitigate the 3-fold increase in total BAL protein observed at 5 h, attributable to albumin influx. The effects of subacute DEX treatment (3.8 mg/kg per day, for 3 days) on cell-surface expression of the adhesion molecules CD11a, CD11b, and L-selectin were determined by flow cytometric analysis of peripheral blood and autologous BAL PMN. Compared with peripheral blood PMN, exudative PMN had 4-fold greater CD11b expression, no change in CD11a, and loss of L-selectin immunoreactivity 5 h after LPS challenge. The upregulation of CD11b on exudative PMN was insensitive to DEX pretreatment, which, together with a failure to suppress MIP-2 levels, provides a possible explanation for the lack of efficacy of steroids in the management of ARDS.

THE EARLY RELEASE OF INTERLEUKIN-2, TUMOR NECROSIS FACTOR-α AND INTERFERON-γ AFTER ISCHEMIA REPERFUSION INJURY IN THE LUNG ALLOGRAFT

A period of cold and warm ischemia is obligatory when performing lung transplantation. Subtle ischemia-reperfusion injury induced in the course of transplantation can pass undetected or cause a short phase of reversible lung dysfunction. We hypothesized that ischemia-reperfusion injury may result in the local release of cytokines that have the capability to mediate acute lung injury early following transplantation. To test this hypothesis, 10 mongrel dogs were subjected to left lung allotransplantation. As performed in the clinical setting, donor lungs were preserved with Eurocollins solution and stored at 4 degrees C for 4 hr, which was followed by 1 hr of warm ischemia. Recipients received standard immunosuppression of cyclosporine, azathioprine, and low dose steroids. Bronchoalveolar lavage (BAL) and open lung biopsies were performed before operation and at approximately 1 hr, 4 hr, 24 hr, and 1 week after transplantation. A significant increase in BAL IL-2 levels was observed 4 hr after surgery (0 hr: 349 +/- 138 pg/ml; 4 hr: 757 +/- 284 pg/ml) (mean +/- SEM) (P < 0.05) which subsequently decreased 24 hr (320 +/- 168 pg/ml) after transplantation. BAL TNF-alpha levels were significantly increased 1 hr after transplantation (P < 0.05) (0 hr: 3.4 +/- 0.65 pg/ml; 1 hr: 13.3 +/- 8.0 pg/ml) returning to baseline after 24 hr (5.8 +/- 2.8 pg/ml). BAL IFN-gamma levels also significantly increased 1 and 4 hr after transplantation (0 hr: 7.2 +/- 2.1 pg/ml; 1 hr: 68.2 +/- 49.2 pg/ml; 4 hr: 301 +/- 131 pg/ml) (P < 0.05). This decreased back to baseline after 24 hr and 1 week (5.2 +/- 1.2 pg/ml and 9.7 +/- 7.9 pg/ml, respectively). There were no changes detected in plasma levels of cytokines. Histology showed evidence of grade 1-2 rejection after 1 week. We conclude that subjection of a lung allograft to standard periods of cold-warm ischemia will result in a temporary early elevation of IL-2, TNF-alpha, and IFN-gamma detectable only in the bronchoalveolar compartment. Such local increase in cytokines in the lung allograft may play an important role in the development of early allograft dysfunction.