Hyaluronan blocks human neutrophil elastase (HNE)-induced airway responses in sheep
ABSTRACT Hyaluronan (HA) blocks inhaled porcine pancreatic elastase-induced bronchoconstriction in sheep with airway hypersensitivity to Ascaris suum antigen. Since elastases from other species may display different catalytic properties compared to the human enzyme, we tested the efficacy of HA on human neutrophil elastase (HNE)-induced airway responses. We measured pulmonary resistance in allergic sheep before and after inhalation of HNE alone and after pretreatment with a 150 kD-HA (LKDHA; 3 and 15 mg), or a 300 kD-HA (HKDHA; 6, 7.5, and 15 mg). HKDHA (3 mg) was given either 0.5, 4, or 8 h before HNE challenge; LKDHA (15 mg) and HKDHA (6, 7.5, and 15 mg) were given 8 h before challenge. HNE caused an acute bronchoconstriction which was blocked by 3 mg LKDHA given 0.5 or 4 h before challenge. LKDHA (3 mg) given 8 h before challenge was ineffective, but protection was achieved by increasing the dose to 15 mg. When HKDHA at 6, 7.5, and 15 mg was given 8 h before challenge a dose-dependent inhibition of the HNE-induced airway response was observed. We conclude that HA inhibits HNE-induced airway responses and that within the range of 150-300 kD, dose rather than molecular weight may be the most important determinant of pretreatment time resulting in a protective effect.
- SourceAvailable from: Håkan Sandler
[Show abstract] [Hide abstract]
- "A decreased concentration of HA and its major transmembrane glycoprotein receptor, CD44, has been shown to increase unwanted human neutrophil elastase activity (32–34) and also to promote leukocyte extravasation and formation of pro-inflammatory cytokines (35,36). In the present study, the concentration of HA in plasma was increased 90 min after thrombin infusion, at which time liver blood flow and cardiac output were decreased. "
ABSTRACT: Hyaluronan (HA) is a component of the extracellular matrix in lung tissue and is normally present at low concentrations in blood. HA is rapidly cleared from blood by the liver. Increased concentrations of plasma HA have been found in patients with acute respiratory distress syndrome (ARDS). We investigated changes in HA levels in plasma, bronchoalveolar lavage fluid (BALF), and lung, and their relationship to pretreatment with a leukocyte elastase inhibitor in a rat model of ARDS. Rats were randomly assigned to three groups: control, thrombin, and thrombin plus elastase inhibitor. By use of a radiometric assay, HA was measured in lungs, BALF, and plasma. Tissue samples from the lungs were stained for HA and examined microscopically. Liver circulation and cardiac output were monitored using radiolabeled microspheres. Infusion of thrombin produced a pronounced increase in wet weight to dry weight ratio, and relative lung water content. This increase was blunted by a leukocyte elastase inhibitor. A decrease in lung HA and increases in both BALF and plasma HA were found. The leukocyte elastase inhibitor counteracted not only the decrease in lung tissue HA, but also the increase in plasma HA. Histologically, there was decreased HA-staining of peribronchial and perivascular areas in the injured rat lung. Decreased liver perfusion was observed after infusion of thrombin. The decrease in lung HA may be involved in the development of pulmonary edema in this ARDS model, and leukocyte elastase may be one cause of this decrease. In addition, an elevated plasma HA level may be an indicator of lung injury.Upsala journal of medical sciences 03/2012; 117(1):1-9. DOI:10.3109/03009734.2011.622812 · 1.98 Impact Factor
[Show abstract] [Hide abstract]
- "While our laboratory has concentrated on the use of HA to treat emphysematous lung injury, other investigators have demonstrated a beneficial effect of this agent in animal models of airway hyperreactivity. When aerosolized HA was given to sheep, it significantly reduced bonchoconstriction due to inhalation of either neutrophil or pancreatic elastase (Scuri et al 2001; Scuri and Abraham 2003). In both cases, increasing the molecular weight of HA enhanced its effectiveness. "
ABSTRACT: Hyaluronan (HA), a long-chain polysaccharide, is currently being evaluated as a potential therapeutic agent for a number of inflammatory disorders. The effect of HA on inflammation appears to be related to its molecular size, with larger polysaccharide chains having anti-inflammatory activity and smaller ones having proinflammatory properties. This dichotomous behavior is particularly relevant to the work of our laboratory on an aerosolized preparation of HA to treat pulmonary emphysema. The breakdown of inhaled HA into smaller fragments could possibly induce an inflammatory reaction in the lung that counteracts any beneficial effect. Consequently, the proposed therapeutic use of HA will require development of treatment strategies aimed at minimizing its proinflammatory activity.International Journal of COPD 02/2007; 2(3):283-8. · 3.14 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Hyaluronic acid (HA) is a polysaccharide that is present in human tissues and body fluids. HA has various functions, including a barrier effect, water homeostasis, stabilizing the extracellular matrix, increased mucociliary clearance and elastin injury prevention. It may therefore exert prophylactic activity in the treatment of asthma. We tested the hypothesis that HA inhalation will prevent exercise-induced bronchoconstriction (EIB) in a randomised double-blinded placebo-controlled crossover study. Sixteen asthmatic patients with EIB were included in the study (mean (SD)) (age 24.5 (7.3) yr, FEV1 88.6 (11.3) %predicted, PC20 methacholine (g-mean (SD in DD)) 0.4 (1.5) mg/ml). On two separate visits an exercise challenge was performed 15 min post-inhalation of either HA (3 ml 0.1% in PBS) or placebo (3 ml PBS). The maximum fall in FEV1 and the AUC 30 min post-exercise were used as outcomes. After inhalation of both HA and placebo, baseline FEV1 decreased significantly (HA 4.1 (3.1)%, placebo 2.9 (4.1)%, P<0.017). The maximum fall in FEV1 following exercise challenge was not significantly different between HA versus placebo (median HA 22.50%, placebo 27.20%, P=0.379), as was the AUC (median HA 379.3 min*%fall, placebo 498.9 min*%fall, P=0.501). We conclude that at the current dose, inhaled HA does not significantly protect against EIB. This suggests that HA is not effective as a prophylaxis for EIB in patients with asthma.Pulmonary Pharmacology & Therapeutics 02/2006; 19(4):286-91. DOI:10.1016/j.pupt.2005.04.011 · 2.94 Impact Factor