Acute exacerbations of COPD are associated with significant activation of matrix metalloproteinase 9 irrespectively of airway obstruction, emphysema and infection.

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) are associated with accelerated aggravation of clinical symptoms and deterioration of pulmonary function. The mechanisms by which exacerbations may contribute to airway remodeling and declined lung function are poorly understood. In this study, we investigated if AE-COPD are associated with differential expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in bronchoalveolar lavage (BAL). METHODS: COPD patients undergoing diagnostic bronchoscopy, with either stable disease (n = 53) or AE-COPD (n = 44), matched for their demographics and lung function parameters were included in this study. Protein levels of MMP-2,-9,-12 and of TIMP-1 and -2 in BAL were measured by ELISA. Enzymatic activity of MMP-2 and -9 was assessed by gelatin zymography. RESULTS: We observed that MMP-9, TIMP-1 and TIMP-2 were significantly increased in BAL during AE-COPD. Furthermore, there was a significant negative correlation of MMP-9, TIMP-1 and TIMP-2 with FEV1% predicted and a significant positive correlation of TIMP-1 and TIMP-2 with RV% predicted in AE-COPD. None of MMPs and TIMPs correlated with DLCO% predicted, indicating that they are associated with airway remodeling leading to obstruction rather than emphysema. In AE-COPD the gelatinolytic activity of MMP-2 was increased and furthermore, MMP-9 activation was significantly up-regulated irrespective of lung function, bacterial or viral infections and smoking. CONCLUSIONS: The results of this study indicate that during AE-COPD increased expression of TIMP-1, TIMP-2, and MMP-9 and activation of MMP-9 may be persistent aggravating factors associated with airway remodeling and obstruction, suggesting a pathway connecting frequent exacerbations to lung function decline.

The significance of the F variant of alpha-1-antitrypsin and unique case report of a PiFF homozygote.

BACKGROUND: Inheritance of the F variant of alpha-1-antitrypsin is associated with normal circulating protein levels, but it is believed to be dysfunctional in its ability to inhibit neutrophil elastase and therefore has been implicated as a susceptibility factor for the development of emphysema. In this study, its functional characteristics were determined following the identification of a unique patient with the PiFF phenotype, and the implications as a susceptibility factor for emphysema are considered both in homozygotes and heterozygotes. METHODS: Second order association rate constants were measured for M, Z, S and F variants of alpha-1-antitrypsin with neutrophil elastase and proteinase 3. Clinical characteristics of the PiFF homozygote and six PiFZ heterozygote subjects were studied. RESULTS: The F variant had a reduced association rate constant with neutrophil elastase (5.60 ± 0.83 × 106 M-1 s-1) compared to the normal M variant (1.45 ± 0.02 × 107 M-1 s-1), indicating an increased time to inhibition that was comparable to that of the Z variant (7.34 ± 0.03 × 106 M-1 s-1). The association rate constant for the F variant and proteinase 3 (1.06 ± 0.22 × 106 M-1 s-1) was reduced compared to that with neutrophil elastase, but was similar to that of other alpha-1-antitrypsin variants. Of the six PiFZ heterozygotes, five had airflow obstruction and radiological evidence of emphysema. The PiFF homozygote had airflow obstruction but no emphysema. None of the patients had clinical evidence of liver disease. CONCLUSIONS: The F variant may increase susceptibility to elastase-induced lung damage but not emphysema, whereas co-inheritance with the Z deficiency allele may predispose to emphysema despite reasonable plasma concentrations of alpha-1-antitrypsin.

Stimulation of soluble guanylate cyclase prevents cigarette smoke-induced pulmonary hypertension and emphysema.

RATIONALE: Chronic obstructive pulmonary disease (COPD) is a major cause of death worldwide. No therapy stopping progress of the disease is available. OBJECTIVES: To investigate the role of the soluble guanylate cyclase (sGC)-cGMP axis in development of lung emphysema and pulmonary hypertension (PH) and to test whether the sGC-cGMP axis is a treatment target for these conditions. METHODS: Investigations were performed in human lung tissue from patients with COPD, healthy donors, mice, and guinea pigs. Mice were exposed to cigarette smoke (CS) for 6 hours per day, 5 days per week for up to 6 months and treated with BAY 63-2521. Guinea pigs were exposed to CS from six cigarettes per day for 3 months, 5 days per week and treated with BAY 41-2272. Both BAY compounds are sGC stimulators. Gene and protein expression analysis were performed by quantitative real-time polymerase chain reaction and Western blotting. Lung compliance, hemodynamics, right ventricular heart mass alterations, and alveolar and vascular morphometry were performed, as well as inflammatory cell infiltrate assessment. In vitro assays of cell adhesion, proliferation, and apoptosis have been done. MEASUREMENTS AND MAIN RESULTS: The functionally essential sGC ß1-subunit was down-regulated in patients with COPD and in CS-exposed mice. sGC stimulators prevented the development of PH and emphysema in the two different CS-exposed animal models. sGC stimulation prevented peroxynitrite-induced apoptosis of alveolar and endothelial cells, reduced CS-induced inflammatory cell infiltrate in lung parenchyma, and inhibited adhesion of CS-stimulated neutrophils. CONCLUSIONS: The sGC-cGMP axis is perturbed by chronic exposure to CS. Treatment of COPD animal models with sGC stimulators can prevent CS-induced PH and emphysema.

Elastase induced lung epithelial cell apoptosis and emphysema through placenta growth factor.

Chronic pulmonary obstructive disease (COPD) is the fourth leading cause of death worldwide, however, the pathogenic factors and mechanisms are not fully understood. Pulmonary emphysema is one of the major components of COPD and is thought to result from oxidative stress, chronic inflammation, protease-antiprotease imbalance and lung epithelial (LE) cell apoptosis. In our previous studies, COPD patients were noted to have higher levels of placenta growth factor (PlGF) in serum and bronchoalveolar lavage fluid than controls. In addition, transgenic mice overexpressing PlGF developed pulmonary emphysema and exposure to PlGF in LE cells induced apoptosis. Furthermore, intratracheal instillation of porcine pancreatic elastase (PPE) on to PlGF wild type mice induced emphysema, but not in PlGF knockout mice. Therefore, we hypothesized that PPE generates pulmonary emphysema through the upregulation of PlGF expression in LE cells. The elevation of PlGF then leads to LE cell apoptosis. In the present study, we investigated whether PPE induces PlGF expression, whether PlGF induces apoptosis and whether the downstream mechanisms of PlGF are related to LE cell apoptosis. We found that PPE increased PlGF secretion and expression both in vivo and in vitro. Moreover, PlGF-induced LE cell apoptosis and PPE-induced emphysema in the mice were mediated by c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) pathways. Given these findings, we suggest that the increase in PlGF and PlGF-induced JNK and p38 MAPK pathways contribute to PPE-induced LE cell apoptosis and emphysema. Regulatory control of PlGF and agents against its downstream signals may be potential therapeutic targets for COPD.

Prevalence of underlying lung disease in smokers with epidermal growth factor receptor-mutant lung cancer.

The prevalence of underlying lung diseases, such as emphysema and interstitial lung disease in smokers with epidermal growth factor receptor (EGFR)-mutant lung cancer remains unclear. This study aimed to clarify the correlation between the EGFR mutation status and the prevalence of underlying lung disease in smokers with lung cancer. A total of 88 consecutive smokers with non-small cell or non-squamous cell lung cancer who underwent surgical resection at our hospital from January 2007 through December 2010 were included in this study. The patients were divided into two groups on the basis of the EGFR mutation status: the mutation-positive group (n=19) and the wild-type group (n=69). The results of radiographic assessment via computed tomography (CT) and pulmonary function analysis were compared between the two groups. In the radiological evaluation, CT images at three levels were evaluated by two reviewers. Radiographic assessment revealed that the mutation-positive group tended to have milder emphysematous changes and a lower prevalence of interstitial changes compared with the wild-type group (P=0.13, 0.06). When the analysis was limited to the ipsilateral lung at the nearest CT level to the tumor, emphysematous changes were found to be less common in the mutation-positive group (P=0.02). The prevalence of the emphysematous and/or interstitial changes in the ipsilateral lung at the nearest CT level to the tumor was lower in the mutation-positive group compared to the wild-type group (P=0.005). In the pulmonary function test, the results were comparable between the two groups. In conclusion, according to our results, EGFR-mutant lung cancer was commonly observed in the areas where emphysematous and interstitial changes were absent. EGFR-mutant lung cancer may develop in radiographically normal areas of the lungs, even in smokers. It would be of importance to evaluate the EGFR mutation status in patients with no emphysematous or interstitial changes in the ipsilateral lung near the tumor, regardless of their smoking history. These results should be confirmed in a future prospective study.

Pathobiologic mechanisms of chronic obstructive pulmonary disease.

COPD is a worldwide public health problem that reduces the quality of life. The exact pathways by which CS and other environmental toxins produce COPD are not known. Currently, the leading candidates are (1) the protease-antiprotease hypothesis, (2) the Dutch hypothesis, (3) the British hypothesis, and the (4) autoimmunity hypothesis. Given the heterogeneity of the disease (and phenotypes), it is probably unrealistic that one pathway will fully explain COPD pathophysiology.

Sputum matrix metalloproteinase-12 in patients with chronic obstructive pulmonary disease and asthma: relationship to disease severity.

BACKGROUND: Matrix metalloproteinase (MMP)-12 has been implicated in the pathogenesis of both chronic obstructive pulmonary disease (COPD) and asthma. The influence of disease severity on sputum MMP-12 concentrations and activity is not known. OBJECTIVES: We sought to examine the relationship between disease severity assessed by means of lung function and computed tomography (CT) and induced sputum MMP-12 concentrations and activity in patients with asthma and COPD. METHODS: In 208 subjects (109 asthmatic patients, smokers and never smokers, mild, moderate, and severe; 53 patients with COPD, smokers and exsmokers, mild, moderate, and severe; and 46 healthy control subjects, smokers and never smokers), we measured induced sputum MMP-12 concentrations (ELISA) and enzyme activity (fluorescence resonance energy transfer), sputum cell MMP12 mRNA expression (quantitative PCR [qPCR]), diffusing capacity for carbon monoxide (Dlco), and CT assessment of emphysema (percentage of low-attenuation areas at less -950 Hounsfield units). RESULTS: Sputum MMP-12 concentrations are greater in patients with COPD and smokers with asthma than in healthy nonsmokers (P = .003 and P = .035, respectively) but similar to those seen in healthy smokers. In patients with COPD, disease severity, when measured by means of CT-assessed emphysema, but not by means of spirometry or Dlco values, is directly associated with sputum MMP-12 concentrations and activity. In the asthma groups there is no significant association between disease severity and sputum MMP-12 concentrations or activity. CONCLUSIONS: Sputum MMP-12 concentrations and activity in patients with COPD are directly associated with the extent of emphysema measured by means of CT. This finding supports a role for MMP-12 in the pathogenesis of COPD and might suggest that blocking MMP-12 activity in patients with COPD could prevent the further development of emphysema.

Copper deficiency induced emphysema is associated with focal adhesion kinase inactivation.

BACKGROUND: Copper is an important regulator of hypoxia inducible factor 1 alpha (HIF-1α) dependent vascular endothelial growth factor (VEGF) expression, and is also required for the activity of lysyl oxidase (LOX) to effect matrix protein cross-linking. Cell detachment from the extracellular matrix can induce apoptosis (anoikis) via inactivation of focal adhesion kinase (FAK). METHODOLOGY: To examine the molecular mechanisms whereby copper depletion causes the destruction of the normal alveolar architecture via anoikis, Male Sprague-Dawley rats were fed a copper deficient diet for 6 weeks while being treated with the copper chelator, tetrathiomolybdate. Other groups of rats were treated with the inhibitor of auto-phosphorylation of FAK, 1,2,4,5-benzenetetraamine tetrahydrochloride (1,2,4,5-BT) or FAK small interfering RNA (siRNA). PRINCIPAL FINDINGS: Copper depletion caused emphysematous changes, decreased HIF-1α activity, and downregulated VEGF expression in the rat lungs. Cleaved caspase-3, caspase-8 and Bcl-2 interacting mediator of cell death (Bim) expression was increased, and the phosphorylation of FAK was decreased in copper depleted rat lungs. Administration of 1,2,4,5-BT and FAK siRNA caused emphysematous lung destruction associated with increased expression of cleaved capase-3, caspase-8 and Bim. CONCLUSIONS: These data indicate that copper-dependent mechanisms contribute to the pathogenesis of emphysema, which may be associated with decreased HIF-1α and FAK activity in the lung.

Protein phosphatase 2A regulates innate immune and proteolytic responses to cigarette smoke exposure in the lung.

Protein phosphatase 2A (PP2A) is the primary serine-threonine phosphatase of eukaryotic cells, and changes in its activity have been linked to neoplastic and neurodegenerative diseases. However, the role of PP2A in noncancerous lung diseases such as chronic obstructive pulmonary disease (COPD) has not been previously examined. This study determined that PP2A activity was significantly increased in the lungs of advanced emphysema subjects compared with age-matched controls. Furthermore, we found that cigarette smoke exposure increases PP2A activity in mouse lung in vivo and in primary human small airway epithelial (SAE) cells in vitro. In mice, intratracheal transfection of PP2A protein prior to cigarette smoke exposure prevented acute smoke-induced lung inflammation. Conversely, inhibiting PP2A activity during smoke exposure exacerbated inflammatory responses in the lung. To further determine how PP2A modulates the responses to cigarette smoke in the lung, enzyme levels were manipulated in SAE cells using protein transfection and short hairpin RNA (shRNA) techniques. Increasing PP2A activity in SAE cells via PP2A protein transfection downregulated cytokine expression and prevented the induction of proteases following cigarette smoke extract (CSE) treatment. Conversely, decreasing enzymatic activity by stably transfecting SAE cells with shRNA for the A subunit of PP2A exacerbated these smoke-mediated responses. This study establishes that PP2A induction by cigarette smoke modulates immune and proteolytic responses to cigarette smoke exposure. Together, these findings suggest that manipulation of PP2A activity may be a plausible means to treat COPD and other inflammatory diseases.

Imbalance of apoptosis and cell proliferation contributes to the development and persistence of emphysema.

BACKGROUND: We postulate that in adults there is an established lung structure maintenance program and that lung alveolar septal cells are undergoing both continuous apoptosis and proliferation. Whereas lung cell apoptosis has been recognized in human emphysema, little is known about cell proliferation. METHODS: Using a novel rat model of emphysema, induced by intratracheal instillation of cigarette smoke extract (CSE), we investigated the dynamics of emphysematous lung destruction. Emphysematous lung destruction was determined by measuring mean linear intercept and destructive index. Lung injury and repair were assessed by immunohistochemistry and Western blot analysis for active caspase-3 and proliferating cell nuclear antigen (PCNA) after 4, 8, and 12 weeks of CSE instillations. RESULTS: The emphysematous lung tissue destruction was present at 4 weeks of CSE treatment and progressed to 8 weeks. Spontaneous repair began at 12 weeks. Treatment with a peroxisome proliferator activated receptor (PPAR)α+γ agonist or granulocyte and macrophage-colony stimulating factor (GM-CSF) for 4 weeks prevented the progression of emphysematous lung destruction and decreased the number of caspase-3-positive cells. CONCLUSION: Apoptosis and cell proliferation occur in this new model of emphysema. Treatment with a PPARα+γ agonist or GM-CSF can inhibit the progression of emphysematous alveolar septal destruction by decreasing alveolar cell apoptosis.

Deletion of vitamin D receptor leads to premature emphysema/COPD by increased matrix metalloproteinases and lymphoid aggregates formation.

Deficiency of vitamin D is associated with accelerated decline in lung function. Vitamin D is a ligand for nuclear hormone vitamin D receptor (VDR), and upon binding it modulates various cellular functions. The level of VDR is reduced in lungs of patients with chronic obstructive pulmonary disease (COPD) which led us to hypothesize that deficiency of VDR leads to significant alterations in lung phenotype that are characteristics of COPD/emphysema associated with increased inflammatory response. We found that VDR knock-out (VDR(-/-)) mice had increased influx of inflammatory cells, phospho-acetylation of nuclear factor-kappaB (NF-κB) associated with increased proinflammatory mediators, and up-regulation of matrix metalloproteinases (MMPs) MMP-2, MMP-9, and MMP-12 in the lung. This was associated with emphysema and decline in lung function associated with lymphoid aggregates formation compared to WT mice. These findings suggest that deficiency of VDR in mouse lung can lead to an early onset of emphysema/COPD because of chronic inflammation, immune dysregulation, and lung destruction.

Lysyl oxidase, a critical intra- and extra-cellular target in the lung for cigarette smoke pathogenesis.

Cigarette smoke (CS), a complex chemical mixture, contains more than 4,800 different compounds, including oxidants, heavy metals, and carcinogens, that individually or in combination initiate or promote pathogenesis in the lung accounting for 82% of chronic obstructive pulmonary disease (COPD) deaths and 87% of lung cancer deaths. Lysyl oxidase (LO), a Cu-dependent enzyme, oxidizes peptidyl lysine residues in collagen, elastin and histone H1, essential for stabilization of the extracellular matrix and cell nucleus. Considerable evidences have shown that LO is a tumor suppressor as exemplified by inhibiting transforming activity of ras, a proto oncogene. CS condensate (CSC), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and cadmium (Cd), major components of CS, down-regulate LO expression at such multiple levels as mRNA, protein and catalytic activity in lung cells in vitro and in vivo indicating LO as a critical intra- and extracellular target for CS pathogenesis in the lung. In view of multiple biological functions and regulation characteristics of the LO gene, molecular mechanisms for CS damage to lung LO and its role in emphysema and cancer pathogenesis are discussed in this review.

All-trans retinoic acid results in irregular repair of septa and fails to inhibit proinflammatory macrophages.

All-trans retinoic acid (ATRA) is controversially discussed in emphysema therapy. We re-evaluated ATRA in the elastase model and hypothesised that beneficial effects should be reflected by increased alveolar surface area, elastin expression and downregulation of inflammatory mediators and matrix metalloproteinases (MMPs). Emphysema was induced by porcine pancreatic elastase versus saline in Sprague-Dawley rats. On days 26-37, rats received daily intraperitoneal injections with ATRA (500 µg · kg(-1) body weight) versus olive oil. Lungs were removed at day 38. Rat alveolar epithelial L2 cells were incubated with/without elastase followed by ATRA- or vehicle-treatment, respectively. ATRA only partially ameliorated structural defects. Alveolar walls exhibited irregular architecture: increased arithmetic mean thickness, reduction in surface coverage by alveolar epithelial cells type II. ATRA only partially restored reduced soluble elastin. It tended to increase the ratio of ED1(+):ED2(+) macrophages. Bronchoalveolar lavage (BAL) cells exhibited a proinflammatory state and high expression of interleukin-1ß, cytokine-induced neutrophil chemoattractant-1, tumour necrosis factor-α, nuclear factor-κB, MMP-2, MMP-9, MMP-12, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in emphysema, with ATRA exerting only few effects. MMP-7 was highly induced by ATRA in healthy but not in emphysematous lungs. ATRA reduced both MMP-2 and TIMP-1 activity in BAL fluid of emphysematous lungs. ATRA-therapy may bear the risk of unwanted side-effects on alveolar septal architecture in emphysematous lungs.

Metalloproteases/anti-metalloproteases imbalance in chronic obstructive pulmonary disease: genetic factors and treatment implications.

PURPOSE OF REVIEW: The aim is to describe the involvement of matrix metalloprotease (MMP), A Disintegrin And Metalloproteases (ADAM), tissue inhibitors of MMP (TIMP) polymorphisms and the role of α-2 Macroglobulin (α-2M) in chronic obstructive pulmonary disease (COPD) development and progression, with a focus on interventions with synthetic MMP inhibitors alone or associated with current drugs used in COPD therapy in order to restore MMPs/TIMPs imbalance. RECENT FINDINGS: COPD is one of the major causes of death in the elderly. It is characterized by progressive development of airflow limitation manifested by decreased forced expiratory volume in one second (FEV1) and reduction in the percentage of FEV1/forced vital capacity. The major pathogenic role is played by metalloproteases (MMPs, ADAMs)/anti-metalloproteases (TIMPs, α-2M) imbalance, which is responsible for MMP overproduction not sufficiently counteracted by TIMPs or α-2M. As a consequence, the lung extracellular matrix is destroyed with obstruction of small airways and appearance of emphysema. SUMMARY: The disease is mainly caused by exposure to cigarette smoke or noxious gases and air pollutants, but also genetic factors are involved. Among them, polymorphisms of MMPs (MMP1, MMP2, MMP9, MMP12), ADAMs (ADAM33) and TIMPs (TIMP1, TIMP2) are relevant, in which the inflammation and the smoking habit play key roles especially in unfavorable allele carriers. The association between these polymorphisms and the current drugs paves the way for personalized therapy with a great impact at clinical level.

Association of GSTM1 and GSTT1 polymorphisms with chronic obstructive pulmonary disease in a Tunisian population.

GSTM1 and GSTT1 polymorphisms have been proposed in relationship with chronic obstructive pulmonary disease (COPD). We investigated the association between these polymorphisms and COPD (as well as its subtypes emphysema and chronic bronchitis) in 234 COPD patients and 182 healthy controls in the Tunisian population. Genotyping was performed using multiplex PCR. GSTM1-null genotype frequency was significantly higher in COPD patients than in controls (P = 0.02); however, multivariate analysis of cofounding variables showed no independent association with this genotype (P = 0.073). In contrast, the association of the GSTM1-null genotype with emphysema was significant, even after adjustment for risk factors (P = 0.011). There were no significant differences in GSTT1 genotypes between patients and controls. The GSTM1 null allele is likely not an independent risk factor for COPD but is related to emphysema, whereas the GSTT1 gene is not associated with the disease.

Protease inhibitors: a panacea?

With the increasing evidence of protease involvement in several diseases, novel strategies for drug development involve the use of protease inhibitors (PIs). The local balance between protease inhibitors and proteases is an important determinant of the occurrence and progression of a particular disease. Hence, enzymes and their cognate inhibitors are finding their applications as diagnostic and prognostic markers. PIs are widely implicated for their use in host defense against infection, tissue repair and matrix production, blood coagulation, cancer, and they are, therefore, the current focus as therapeutic alternatives for major diseases such as AIDS and Alzheimer's diseases. This review is a brief summary of the varied role of protein protease inhibitors in controlling the activity of aberrant enzymes in several diseases afflicting mankind today.

Cigarette smoke induces nucleic-acid oxidation in lung fibroblasts.

Oxidative stress is widely proposed as a pathogenic mechanism for chronic obstructive pulmonary disease (COPD), but the molecular pathway connecting oxidative damage to tissue destruction remains to be fully defined. We suggest that reactive oxygen species (ROS) oxidatively damage nucleic acids, and this effect requires multiple repair mechanisms, particularly base excision pathway components 8-oxoguanine-DNA glycosylase (OGG1), endonuclease III homologue 1 (NTH1), and single-strand-selective monofunctional uracil-DNA glycosylase 1 (SMUG1), as well as the nucleic acid-binding protein, Y-box binding protein 1 (YB1). This study was therefore designed to define the levels of nucleic-acid oxidation and expression of genes involved in the repair of COPD and in corresponding models of this disease. We found significant oxidation of nucleic acids localized to alveolar lung fibroblasts, increased levels of OGG1 mRNA expression, and decreased concentrations of NTH1, SMUG1, and YB1 mRNA in lung samples from subjects with very severe COPD compared with little or no COPD. Mice exposed to cigarette smoke exhibited a time-dependent accumulation of nucleic-acid oxidation in alveolar fibroblasts, which was associated with an increase in OGG1 and YB1 mRNA concentrations. Similarly, human lung fibroblasts exposed to cigarette smoke extract exhibited ROS-dependent nucleic-acid oxidation. The short interfering RNA (siRNA)-dependent knockdown of OGG1 and YB1 expression increased nucleic-acid oxidation at the basal state and after exposure to cigarette smoke. Together, our results demonstrate ROS-dependent, cigarette smoke-induced nucleic-acid oxidation in alveolar fibroblasts, which may play a role in the pathogenesis of emphysema.

Requirement of Fut8 for the expression of vascular endothelial growth factor receptor-2: a new mechanism for the emphysema-like changes observed in Fut8-deficient mice.

alpha1,6-Fucosylation plays key roles in many biological functions, as evidenced by the study of alpha1,6-fucosyltransferase (Fut8) knockout (Fut8(-/-)) mice. Phenotypically, Fut8(-/-) mice exhibit emphysema-like changes in the lung, and severe growth retardation. Fut8(-/-) cells also show marked dysregulation of the TGF-beta1 receptor, EGF receptor, integrin activation and intracellular signalling, all of which can be rescued by reintroduction of Fut8. The results of the present study demonstrated that vascular endothelial growth factor receptor-2 (VEGFR-2) expression was significantly suppressed in Fut8(-/-) mice, suggesting that Fut8 was required for VEGFR-2 expression. The expression of VEGFR-2 mRNA and protein was consistently down-regulated by knockdown of the Fut8 gene with small interference RNA in A549 cells, as well as in TGP49 cells, suggesting that suppression occurs at the level of transcription. In contrast, the expression level of ceramide, an inducer of cell apoptosis, was increased in the lungs of Fut8(-/-) mice. The terminal transferase dUTP nick end-labelling (TUNEL) assay was used to identify apoptotic cells. The number of TUNEL-positive septal epithelia and endothelia cells was significantly increased in the alveolar septa of lungs from Fut8(-/-) mice when in comparison with lungs from wild-type mice. It is well known that, in emphysema, ceramide expression can be greatly enhanced by blockade of the VEGFR-2. Thus, suppression of VEGFR-2 expression may provide a novel explanation for the emphysema-like changes in Fut8(-/-) mice.

Magnitud del enfisema inducido por elastasa: posible relación con el tipo de daño agudo pulmonar / Elastase induced emphysema: possible relationship with the type of acute lung injury

Introduction: Intratracheal instillation of elastase induces diffuse alveolar damage and emphysema development. However, the Syrian Golden hamster develops more severe emphysema than the Sprague-Dawley rat. Although it is known that early events after elastase instillation determine the magnitude of emphysema development, it is not known if there are species differences in the initial pattern of lung response to elastase. Objective: To evaluate whether rats and hamster differ in the early lung response to elastase, using biochemical markers of acute lung injury. Results: Whereas the rat shows a large increase in alveolar-capillary permeability and few hemorrhagic changes, the hamster shows significant amount of hemorrhage and a small increase in alveolar capillary permeability. Conclusions: There are differences between rats and hamsters in the initial lung response to elastase that could influence the magnitude of emphysema development.

Introducción: El modelo de instilación intratraqueal de elastasa induce daño alveolar difuso y destrucción de la matriz extracelular con desarrollo de enfisema. Sin embargo, el hámster Syrian Golden desarrolla enfisema más severo que el de la rata Sprague-Dawley. Si bien se sabe que los eventos tempranos después de la instilación de elastasa determinan la magnitud del enfisema, se desconoce si existen diferencias entre especies en la respuesta pulmonar temprana. Objetivo: Evaluar si existen diferencias entre ratas y hamsters en la respuesta pulmonar inicial después de la elastasa, mediante el uso de marcadores bioquímicos de daño pulmonar agudo. Resultados: Mientras la rata experimenta un gran aumento de permeabilidad alvéolo-capilar y pocos fenómenos hemorrágicos, el hamster presenta abundante hemorragia y escaso aumento de la permeabilidad. Conclusiones: Existen diferencias entre ratas y hamsters en la respuesta pulmonar inicial frente a la elastasa, que podrían tener relación con las diferencias en magnitud del enfisema.

Lysyl oxidase as a potential therapeutic target.

Lysyl oxidase (LOX) is a copper-dependent amine oxidase that catalyzes the covalent cross-link of collagens and elastin in the extracellular environment, thereby determining the mechanical properties of extracellular matrix (ECM) and connective tissues. ECM remodeling is a common feature of diverse pathologic processes. Therefore, dysregulation of LOX could underlie the onset and progression of multiple pathologies affecting connective tissue, such as fibrotic processes, tumor progression and metastasis and neurodegenerative and cardiovascular diseases. Here we review clinical and experimental evidence that supports a role for LOX in the pathophysiology of those processes and point out LOX as a potential therapeutic target.