Keratinocyte growth factor promotes epithelial survival and resolution in a human model of lung injury.

RATIONALE: Increasing epithelial repair and regeneration may hasten resolution of lung injury in patients with the acute respiratory distress syndrome (ARDS). In animal models of ARDS, keratinocyte growth factor (KGF) reduces injury and increases epithelial proliferation and repair. The effect of KGF in the human alveolus is unknown. OBJECTIVES: To test whether KGF can attenuate alveolar injury in a human model of ARDS. METHODS: Volunteers were randomized to intravenous KGF (60 µg/kg) or placebo for 3 days, before inhaling 50 µg LPS. Six hours later, subjects underwent bronchoalveolar lavage (BAL) to quantify markers of alveolar inflammation and cell-specific injury. MEASUREMENTS AND MAIN RESULTS: KGF did not alter leukocyte infiltration or markers of permeability in response to LPS. KGF increased BAL concentrations of surfactant protein D, matrix metalloproteinase (MMP)-9, IL-1Ra, granulocyte-macrophage colony-stimulating factor (GM-CSF), and C-reactive protein. In vitro, BAL fluid from KGF-treated subjects inhibited pulmonary fibroblast proliferation, but increased alveolar epithelial proliferation. Active MMP-9 increased alveolar epithelial wound repair. Finally, BAL from the KGF-pretreated group enhanced macrophage phagocytic uptake of apoptotic epithelial cells and bacteria compared with BAL from the placebo-treated group. This effect was blocked by inhibiting activation of the GM-CSF receptor. CONCLUSIONS: KGF treatment increases BAL surfactant protein D, a marker of type II alveolar epithelial cell proliferation in a human model of acute lung injury. Additionally, KGF increases alveolar concentrations of the antiinflammatory cytokine IL-1Ra, and mediators that drive epithelial repair (MMP-9) and enhance macrophage clearance of dead cells and bacteria (GM-CSF). Clinical trial registered with ISRCTN 98813895.

Simvastatin decreases lipopolysaccharide-induced pulmonary inflammation in healthy volunteers.

RATIONALE: Simvastatin inhibits inflammatory responses in vitro and in murine models of lung inflammation in vivo. As simvastatin modulates a number of the underlying processes described in acute lung injury (ALI), it may be a potential therapeutic option. OBJECTIVES: To investigate in vivo if simvastatin modulates mechanisms important in the development of ALI in a model of acute lung inflammation induced by inhalation of lipopolysaccharide (LPS) in healthy human volunteers. METHODS: Thirty healthy subjects were enrolled in a double-blind, placebo-controlled study. Subjects were randomized to receive 40 mg or 80 mg of simvastatin or placebo (n = 10/group) for 4 days before inhalation of 50 microg LPS. Measurements were performed in bronchoalveolar lavage fluid (BALF) obtained at 6 hours and plasma obtained at 24 hours after LPS challenge. Nuclear translocation of nuclear factor-kappaB (NF-kappaB) was measured in monocyte-derived macrophages. MEASUREMENTS AND MAIN RESULTS: Pretreatment with simvastatin reduced LPS-induced BALF neutrophilia, myeloperoxidase, tumor necrosis factor-alpha, matrix metalloproteinases 7, 8, and 9, and C-reactive protein (CRP) as well as plasma CRP (all P < 0.05 vs. placebo). There was no significant difference between simvastatin 40 mg and 80 mg. BALF from subjects post-LPS inhalation induced a threefold up-regulation in nuclear NF-kappaB in monocyte-derived macrophages (P < 0.001); pretreatment with simvastatin reduced this by 35% (P < 0.001). CONCLUSIONS: Simvastatin has antiinflammatory effects in the pulmonary and systemic compartment in humans exposed to inhaled LPS.

Phenotypic differences between oral and skin fibroblasts in wound contraction and growth factor expression.

Wounds of the oral mucosa heal in an accelerated fashion with reduced scarring compared with cutaneous wounds. The differences in healing outcome between oral mucosa and skin could be because of phenotypic differences between the respective fibroblast populations. This study compared paired mucosal and dermal fibroblasts in terms of collagen gel contraction, alpha-smooth muscle actin expression (alpha-SMA), and production of the epithelial growth factors: keratinocyte growth factor (KGF) and hepatocyte growth factor/scatter factor (HGF). The effects of transforming growth factor -beta1 and -beta3 on each parameter were also determined. Gel contraction in floating collagen lattices was determined over a 7-day period. alpha-SMA expression by fibroblasts was determined by Western blotting. KGF and HGF expression were determined by an enzyme-linked immunosorbent assay. Oral fibroblasts induced accelerated collagen gel contraction, yet surprisingly expressed lower levels of alpha-SMA. Oral cells also produced significantly greater levels of both KGF and HGF than their dermal counterparts. Transforming growth factor-beta1 and -beta3, over the concentration range of 0.1-10 ng/mL, had similar effects on cell function, stimulating both gel contraction and alpha-SMA production, but inhibiting KGF and HGF production by both cell types. These data indicate phenotypic differences between oral and dermal fibroblasts that may well contribute to the differences in healing outcome between these two tissues.

The cytotoxic effects of human neutrophil peptide-1 (HNP1) and lactoferrin on oral squamous cell carcinoma (OSCC) in vitro.

Alpha-defensin or human neutrophil peptide-1 (HNP1) is a neutrophil-derived antimicrobial peptide with cytotoxic effects towards cancer cells. Lactoferrin is also stored in human neutrophils and is a glycoprotein involved in mediating cytotoxicity towards tumour cells. This study investigated the sensitivity of normal oral keratinocyte and oral squamous cell carcinoma (OSCC) cells to HNP1 and lactoferrin in various combinations. A concentration of 100 microg/ml HNP1 induced the most significant cytotoxic effect on both normal and OSCC cells. Lactoferrin (12.5, 25 and 250 microg/ml) also significantly induced cell death in OSCC cells after 72 h. Of note, a combination of 10 microg/ml HNP1 and 50 microg/ml lactoferrin induced a differential effect, not observed with either concentration alone, which stimulated proliferation in normal cells, but induced cell death in OSCC cells throughout the study. These results indicate a potentially important co-operative role for HNP1 and lactoferrin in facilitating a selective cytotoxic effect on tumour cells.