Varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs sustained-release bupropion and placebo for smoking cessation: a randomized controlled trial

CONTEXT

The alpha4beta2 nicotinic acetylcholine receptors (nAChRs) are linked to the reinforcing effects of nicotine and maintaining smoking behavior. Varenicline, a novel alpha4beta2 nAChR partial agonist, may be beneficial for smoking cessation.

OBJECTIVE

To assess efficacy and safety of varenicline for smoking cessation compared with sustained-release bupropion (bupropion SR) and placebo.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, parallel-group, placebo- and active-treatment-controlled, phase 3 clinical trial conducted at 19 US centers from June 19, 2003, to April 22, 2005. Participants were 1025 generally healthy smokers (> or =10 cigarettes/d) with fewer than 3 months of smoking abstinence in the past year, 18 to 75 years old, recruited via advertising.

INTERVENTION

Participants were randomly assigned in a 1:1:1 ratio to receive brief counseling and varenicline titrated to 1 mg twice per day (n = 352), bupropion SR titrated to 150 mg twice per day (n = 329), or placebo (n = 344) orally for 12 weeks, with 40 weeks of nondrug follow-up.

MAIN OUTCOME MEASURES

Primary outcome was the exhaled carbon monoxide-confirmed 4-week rate of continuous abstinence from smoking for weeks 9 through 12. A secondary outcome was the continuous abstinence rate for weeks 9 through 24 and weeks 9 through 52.

RESULTS

For weeks 9 through 12, the 4-week continuous abstinence rates were 44.0% for varenicline vs 17.7% for placebo (odds ratio [OR], 3.85; 95% confidence interval [CI], 2.70-5.50; P<.001) and vs 29.5% for bupropion SR (OR, 1.93; 95% CI, 1.40-2.68; P<.001). Bupropion SR was also significantly more efficacious than placebo (OR, 2.00; 95% CI, 1.38-2.89; P<.001). For weeks 9 through 52, the continuous abstinence rates were 21.9% for varenicline vs 8.4% for placebo (OR, 3.09; 95% CI, 1.95-4.91; P<.001) and vs 16.1% for bupropion SR (OR, 1.46; 95% CI, 0.99-2.17; P = .057). Varenicline reduced craving and withdrawal and, for those who smoked while receiving study drug, smoking satisfaction. No sex differences in efficacy for varenicline were observed. Varenicline was safe and generally well tolerated, with study drug discontinuation rates similar to those for placebo. The most common adverse events for participants receiving active-drug treatment were nausea (98 participants receiving varenicline [28.1%]) and insomnia (72 receiving bupropion SR [21.9%]).

CONCLUSION

Varenicline was significantly more efficacious than placebo for smoking cessation at all time points and significantly more efficacious than bupropion SR at the end of 12 weeks of drug treatment and at 24 weeks.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00141206.

Smad3 deficiency alters key structural elements of the extracellular matrix and mechanotransduction of wound closure

The loss of TGFbeta or its downstream mediator, Smad3, key players in tissue repair, accelerates closure of incisional wounds in mice. In contrast, we now report that excisional ear wounds in mice lacking Smad3 enlarge compared with wild-type controls resulting from changes in extracellular matrix molecules, which alter the mechanotransduction properties of these wounds. Specifically, levels of elastin and glycosoaminoglycans are increased, collagen fibers are more compactly organized, and matrix modulators like integrins, TGFbeta1, and matrix metalloproteinases (MMPs) are altered both basally and after wounding in Smad3 knockout mice. Mechanical testing of dorsal skin correlates these changes in matrix composition with functional parameters, specifically an increased elastic modulus, suggesting an imbalance of tissue forces. We propose that the altered mechanical elastic properties translate into a persistent retractile force that is opposed by decreased wound contractile forces contributing to the enlarging ear wound in Smad3 knockout mice. These studies highlight a previously undescribed role for Smad3 in the mechanotransduction of matrix unsupported ear wound closure.

Transforming Growth Factor-β Receptor Type 1 (TGFβRI) Kinase Activity but Not p38 Activation Is Required for TGFβRI-Induced Myofibroblast Differentiation and Profibrotic Gene Expression

Transforming growth factor-beta (TGFbeta) is a major mediator of normal wound healing and of pathological conditions involving fibrosis, such as idiopathic pulmonary fibrosis. TGFbeta also stimulates the differentiation of myofibroblasts, a hallmark of fibrotic diseases. In this study, we examined the underlying processes of TGFbetaRI kinase activity in myofibroblast conversion of human lung fibroblasts using specific inhibitors of TGFbetaRI (SD-208) and p38 mitogen-activated kinase (SD-282). We demonstrated that SD-208, but not SD-282, inhibited TGFbeta-induced SMAD signaling, myofibroblast transformation, and collagen gel contraction. Furthermore, we extended our findings to a rat bleomycin-induced lung fibrosis model, demonstrating a significant decrease in the number of myofibroblasts at fibroblastic foci in animals treated with SD-208 but not those treated with SD-282. SD-208 also reduced collagen deposition in this in vivo model. Microarray analysis of human lung fibroblasts identified molecular fingerprints of these processes and showed that SD-208 had global effects on reversing TGFbeta-induced genes involved in fibrosis, inflammation, cell proliferation, cytoskeletal organization, and apoptosis. These studies also revealed that although the p38 pathway may not be needed for appearance or disappearance of the myofibroblast, it can mediate a subset of inflammatory and fibrogenic events of the myofibroblast during the process of tissue repair and fibrosis. Our findings suggest that inhibitors such as SD-208 may be therapeutically useful in human interstitial lung diseases and pulmonary fibrosis.

Reactive Nitrogen Species Augment Fibroblast-Mediated Collagen Gel Contraction, Mediator Production, and Chemotaxis

Reactive nitrogen species (RNS) such as peroxynitrite cause cellular injury and tissue inflammation. Excessive production of nitrotyrosine, which is a footprint of RNS, has been observed in the airways of patients with asthma and chronic obstructive pulmonary disease, disorders characterized by tissue remodeling. The aim of this study was to evaluate whether RNS can affect tissue remodeling through direct effects on fibroblasts, and to determine if these effects depend on production of transforming growth factor-beta (TGF-beta). To accomplish this, human fetal lung fibroblasts (HFL-1) were used to assess fibroblast-mediated contraction of floating gels and chemotaxis toward fibronectin. In addition, the ability of fibroblasts to release TGF-beta1, fibronectin, and vascular endothelial growth factor (VEGF) was assessed by enzyme-linked immunosorbent assay. Authentic peroxynitrite significantly augmented gel contraction (P < 0.01) and chemotaxis (P < 0.01) compared with control in a concentration-dependent manner. Similarly, the peroxynitrite donor 3-morpholynosidenonimine hydrochloride (SIN-1) also augmented gel contraction (P < 0.01). RNS also significantly increased TGF-beta1 (P < 0.01), fibronectin (P < 0.01), and VEGF (P < 0.01) release into the media in both 3D gel and monolayer culture. Anti-TGF-beta antibody reversed RNS-augmented gel contraction (P < 0.01) and mediator production (P < 0.01). Anti-TGF-beta antibody also partially, but significantly, reversed RNS-augmented chemotaxis toward fibronectin (P < 0.01). Finally, peroxynitrite enhanced expression of alpha5beta1 integrin, which is a receptor for fibronectin (P < 0.01), and neutralizing anti-TGF-beta antibody suppressed peroxynitrite-augmented alpha5beta1 expression (P < 0.01). These results suggest that RNS can affect the tissue repair process by modulating TGF-beta1.

Chronic Obstructive Pulmonary Disease: Linking Outcomes and Pathobiology of Disease Modification

Recent guidelines define chronic obstructive pulmonary disease (COPD) as a preventable and treatable disease characterized by airflow limitation and systemic consequences. Airflow limitation in COPD worsens over years as assessed by the forced expiratory volume in one second (FEV(1)). Regardless, while it is likely that cardiovascular and other systemic components also worsen as COPD progresses, there are no accepted or validated outcomes to measure such pathophysiologic changes as they relate to COPD disease progression. It is clear that health status in COPD is more closely related to levels of patients' physical functional capacity than it is to changes in FEV(1). Furthermore, the relative contributions of pathoanatomic changes such as small airways fibrosis and pulmonary emphysema to declining airflow remain unknown. These features may even progress at different rates in the same individuals. Although stopping smoking is the only intervention shown to alter the relentless progression of COPD, the resultant slowing of FEV(1) decline takes several years to evince and requires at least 1,000 subjects to demonstrate annual therapeutic benefits of as little as 20 ml. The FEV(1) cannot distinguish between peribronchiolar fibrosis and emphysema and it is feasible that, as techniques are developed and validated, lung imaging methodologies may become important and sensitive outcomes measures of time- and age-dependent lung structural changes in COPD. The development of biomarkers of lung damage, pulmonary inflammation, and systemic disease will be essential to our further understanding of the natural history of COPD and the discovery of new, effective treatments for its progression.

Red blood cells increase secretion of matrix metalloproteinases from human lung fibroblasts in vitro

Tissue remodeling is an important process in many inflammatory and fibrotic lung disorders. RBC may in these conditions interact with extracellular matrix (ECM). Fibroblasts can produce and secrete matrix components, matrix-degrading enzymes (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Imbalance in matrix synthesis/degradation may result in rearrangement of tissue architecture and lead to diseases such as emphysema or fibrosis. Neutrophil elastase (NE), a protease released by neutrophils, is known to activate MMP. We hypothesized that RBC can stimulate secretion of MMPs from human lung fibroblasts and that NE can augment this effect. Human fetal lung fibroblasts were cultured in floating collagen gels with or without RBC. After 4 days, the culture medium was analyzed with gelatin zymography, Western blot, and ELISA for MMP-1, -2, -3 and TIMP-1, -2. RBC augmented NE-induced fibroblast-mediated collagen gel contraction compared with NE alone (18.4+/-1.6%, 23.7+/-1.4% of initial gel area, respectively). A pan-MMP inhibitor (GM-6001) completely abolished the stimulating effect of NE. Gelatin zymography showed that RBC stimulated MMP-2 activity and that NE enhanced conversion to the active form. Addition of GM-6001 completely inhibited MMP-2 activity in controls, whereas it only partially altered RBC-induced MMP activity. Western blot confirmed the presence of MMP-1 and MMP-3 in fibroblasts stimulated with RBC, and ELISA confirmed increased concentrations of pro-MMP-1. We conclude that stimulation of MMP secretion by fibroblasts may explain the ability of RBC to augment fibroblast-mediated collagen gel contraction. This might be a potential mechanism by which hemorrhage in inflammatory conditions leads to ECM remodeling.

Cilomilast for COPD

BACKGROUND

COPD is a relentless, progressive disease. This study evaluated the efficacy of cilomilast, a selective phosphodiesterase (PDE) 4 inhibitor, in the treatment of COPD.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group, multicenter study in subjects with COPD. After a 4-week, single-blind, placebo run-in period, eligible subjects were randomized in a 2:1 ratio to receive oral cilomilast, 15 mg bid, or placebo for 24 weeks. Subjects between 40 and 80 years of age who had received a diagnosis of COPD were eligible for the study. The primary efficacy variables were changes from baseline in trough (ie, predose) FEV1 and in total score of the St. George's Respiratory Questionnaire (SGRQ). A key secondary end point was the incidence rate of COPD exacerbations.

RESULTS

The average change from baseline in FEV1 over 24 weeks in the cilomilast group was an increase of 10 mL compared with a decrease of 30 mL in the placebo group (difference, 40 mL; p = 0.002). When averaged over 24 weeks, there was a clinically significant reduction in the mean total SGRQ score in subjects receiving cilomilast therapy, with a difference of 4.1 U compared with subjects who received placebo (p = 0.001). A greater percentage of subjects in the cilomilast group were exacerbation-free at 24 weeks (74%; p = 0.008) compared with placebo (62%). Adverse events were generally mild or moderate and were not unexpected for this class of medications. GI adverse events that interfered with daily activities (cilomilast, 17%; placebo, 8%) predominantly occurred within the first 3 weeks of initiating cilomilast therapy.

CONCLUSION

Cilomilast is an orally active, potent, and selective inhibitor of PDE-4. Cilomilast maintained pulmonary function and improved health status, and reduced the rate of COPD exacerbations during 24 weeks of treatment. This study supports the use of cilomilast, a novel, selective PDE-4 inhibitor, in subjects with COPD.

TGF-beta1 and serum both stimulate contraction but differentially affect apoptosis in 3D collagen gels

Apoptosis of fibroblasts may be key for the removal of cells following repair processes. Contraction of three-dimensional collagen gels is a model of wound healing and remodeling. Here two potent inducers of contraction, TGF-β1 and fetal calf serum (FCS) were evaluated for their effect on fibroblast apoptosis in contracting collagen gels. Human fetal lung fibroblasts were cultured in floating type I collagen gels, exposed to TGF-β1 or FCS, and allowed to contract for 5 days. Apoptosis was evaluated using TUNEL and confirmed by DNA content profiling. Both TGF-β1 and serum significantly augmented collagen gel contraction. TGF-β1 also increased apoptosis assessed by TUNEL positivity and DNA content analysis. In contrast, serum did not affect apoptosis. TGF-β1 induction of apoptosis was associated with augmented expression of Bax, a pro-apoptotic member of the Bax/Bcl-2 family, inhibition of Bcl-2, an anti-apoptotic member of the same family, and inhibition of both cIAP-1 and XIAP, two inhibitors of the caspase cascade. Serum was associated with an increase in cIAP-1 and Bcl-2, anti-apoptotic proteins. Interestingly, serum was also associated with an apparent increase in Bax, a pro-apoptotic protein. Blockade of Smad3 with either siRNA or by using murine fibroblasts deficient in Smad3 resulted in a lack of TGF-β induction of augmented contraction and apoptosis. Contraction induced by different factors, therefore, may be differentially associated with apoptosis, which may be related to the persistence or resolution of the fibroblasts that accumulate following injury.

Physician and patient perceptions in COPD: the COPD Resource Network Needs Assessment Survey

PURPOSE

Chronic obstructive pulmonary disease (COPD), the fourth leading cause of death in the United States, has received disproportionately little attention from physicians and institutions. National data are lacking on patient and physician perceptions of and patterns of care for COPD.

METHODS

Linked surveys were administered to national samples of patients with COPD, primary care physicians, and pulmonologists to evaluate perceptions of COPD severity and quality of life, attitudes about COPD, health insurance barriers to COPD care, sources of information, and knowledge about COPD diagnosis and treatment.

RESULTS

Overall, 1023 patients with COPD and 1051 primary care physicians and pulmonologists responded to the surveys. Despite experiencing significant symptoms and high health care use, the majority of patients were satisfied with their care. Eighty-eight percent of physicians agreed with the statement that COPD is a "self-inflicted" disease, and more than one third were nihilistic about the treatment of patients who continued to smoke. Patients and physicians reported that insurance problems impeded access to therapies. Patients were generally uninformed about COPD; 54% of primary care physicians were aware of any COPD guidelines. Both patient and physician surveys demonstrated continued confusion about the diagnosis of COPD and treatment choices. There was frequent use of regular oral steroids despite demonstrated lack of efficacy and under-use of pulmonary rehabilitation despite proven efficacy.

CONCLUSIONS

Patients with COPD have a high prevalence of activity limitations. Although most physicians believed that proper treatment can slow progression, inadequate knowledge and poor adherence to practice guidelines, together with insurance impediments, negatively impact COPD care.

Proposal for a multidimensional staging system for chronic obstructive pulmonary disease

The severity of chronic obstructive pulmonary disease (COPD) is currently assessed using a single physiological measurement, the forced expiratory volume in 1s (FEV1). COPD, however, has complex effects on other aspects of respiratory function, and in many patients is associated with important systemic changes. We hypothesized that a multidimensional staging system for COPD could provide a more complete assessment of the disease's impact. We considered over 40 potential staging variables, evaluating them according to sensitivity to change, measured reproducibly, independence of the information they provide and prognostic value. We finally selected three: FEV1 (including arterial blood gas measurements when FEV1 falls below 35% predicted), Medical Research Council dyspnea scale and body mass index (BMI). Each measure correlates independently with prognosis in COPD, is supported by a significant body of literature and serves as a surrogate for other potentially important variables. We then used principal components analysis (PCA) to determine the degree of association between 30 of the potential variables measured in 813 stable COPD patients. Using PCA, six groups of measurements defined independent categories of patient information: pulmonary function (including FEV1), symptoms of cough and sputum, dyspnea, health status, bronchodilator reversibility and BMI. These include the three principal variables selected for the staging system. Although the staging boundaries were based on existing literature, they have proven useful in predicting survival. We conclude that a multidimensional grading system is useful to assess the impact of COPD.

Smad3 mediates TGF-beta1-induced collagen gel contraction by human lung fibroblasts

Transforming growth factor-beta1 (TGF-beta1) is a key mediator in tissue repair and fibrosis. Using small interference RNA (siRNA), the role of Smad2 and Smad3 in TGF-beta stimulation of human lung fibroblast contraction of collagenous matrix and induction of alpha-SMA and the role of alpha-SMA in contraction were assessed. HFL-1 cells were transfected with Smad2, Smad3 or control-siRNA, and cultured in floating Type I collagen gels +/- -TGF-beta1. TGF-beta1 augmented gel contraction in Smad2-siRNA- and control-siRNA-treated cells, but had no effect in Smad3-siRNA-treated cells. Similarly, TGF-beta1 upregulated alpha-SMA in Smad2-siRNA- and control-siRNA-treated cells, but had no effect on Smad3-siRNA-treated cells. Alpha-SMA-siRNA-treated cells did not contact the collagen gels with or without TGF-beta1, suggesting alpha-SMA is required for gel contraction. Thus, Smad3 mediates TGF-beta1-induced contraction and alpha-SMA induction in human lung fibroblasts. Smad3, therefore, could be a target for blocking contraction of human fibrotic tissue induced by TGF-beta1.

Challenges and Opportunities for Combination Therapy in Chronic Obstructive Pulmonary Disease

Advances in the understanding of chronic obstructive pulmonary disease have presented a number of novel therapeutic opportunities. More extensive use of drug combinations is likely, but the development of these therapies presents a number of challenges. In clinical trials, a combination must be tested not only against placebo but also against each of its components, and the false-positive error rate increases rapidly with multiple comparisons. Thus, more groups of subjects must be studied, and more individuals within each group must be studied, in order to ensure statistical significance. Another challenge is that the relatively slow progression of chronic obstructive pulmonary disease and the lack of specificity of commonly used outcome variables complicate the evaluation of all therapies, including combinations. In analogy to genomics and proteomics (evaluation of the pattern of expression of many things simultaneously), it may be more useful to adopt an approach that is here dubbed "clinicomics": consideration of multiple features of chronic obstructive pulmonary disease that are evaluated routinely, for example, with a well-done history and physical examination. The use of a truly multidimensional outcome parameter promises an entirely novel paradigm for the assessment of novel combinations of therapies.

Pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) is characterized and defined by limitation of expiratory airflow. This can result from several types of anatomical lesions, including loss of lung elastic recoil and fibrosis and narrowing of small airways. Inflammation, edema, and secretions also contribute variably to airflow limitation. Smoking can cause COPD through several mechanisms. First, smoke is a powerful inducer of an inflammatory response. Inflammatory mediators, including oxidants and proteases, are believed to play a major role in causing lung damage. Smoke can also alter lung repair responses in several ways. Inhibition of repair may lead to tissue destruction that characterizes emphysema, whereas abnormal repair can lead to the peribronchiolar fibrosis that causes airflow limitation in small airways. Genetic factors likely play a major role and probably account for much of the heterogeneity susceptibility to smoke and other factors. Many factors may play a role, but to date, only alpha-1 protease inhibitor deficiency has been unambiguously identified. Exposures other than cigarette smoke can contribute to the development of COPD. Inflammation of the lower respiratory tract that results from asthma or other chronic disorders may also contribute to the development of fixed airway obstruction. COPD is not only a disease of the lungs but is also a systemic inflammatory disorder. Muscular weakness, increased risk for atherosclerotic vascular disease, depression, osteoporosis, and abnormalities in fluids and electrolyte balance may all be consequences of COPD. Advances in understanding the pathogenesis of COPD have the potential for identifying new therapeutic targets that could alter the natural history of this devastating disorder.

Exacerbations and progression of disease in asthma and chronic obstructive pulmonary disease

Exacerbations, characterized by an increase in patients' symptoms above baseline, are characteristic of both chronic obstructive pulmonary disease (COPD) and asthma. Prevention of exacerbations and their expedient treatment are major goals for reducing the morbidity and cost of both conditions. Exacerbations, however, may also adversely affect the natural history of these disorders, perhaps by contributing to increased rates of lung function decline, systemic effects, and premature mortality. Although the available information is limited, the course of COPD is affected adversely by exacerbations in multiple ways. First, exacerbations likely lead to structural alterations in the lung and to permanently worsened airflow. Second, health status is adversely affected by exacerbations, and although the mechanisms are unclear, the effects are long lasting and may be irreversible. Less is known in asthma about the effect of exacerbations on natural history, but many of the same pathogenetic processes involved in COPD exacerbations likely play a role in some subjects with asthma as well. Future studies of how exacerbation affects the "natural history" of asthma and COPD will require a better understanding of the heterogeneity of exacerbations but promises to identify new therapeutic strategies to treat these disorders.

Leukotriene D4 potentiates fibronectin-induced migration of human lung fibroblasts

Fibroblasts play an important role in the repair and remodeling processes following injury. Leukotriene D4 (LTD4) is a potent mediator in inflammatory processes, but the direct effect of cysteinyl leukotrienes on fibroblast migration remains unelucidated. In this study, the effect of the LTD4 on normal human lung fibroblasts (NHLF) chemotaxis induced by human plasma fibronectin (HFn) was investigated using the modified Boyden's chamber technique. LTD4 potentiated NHLF chemotaxis to HFn in concentration-dependent manner. A specific cysteinyl leukotriene receptor type 1 antagonist, pranlukast inhibited this effect, indicating that LTD4 affected cell migration via its specific receptor. The potentiating effect of LTD4 on fibroblast chemotaxis was completely abolished by pertussis toxin (PTX), suggesting that LTD4-induced effect was dependent on PTX-sensitive Gi/o signaling. These findings suggest that LTD4 has a potential to augment fibroblast chemotaxis, and to contribute to regulation of the wound healing and following remodeling in fibrotic processes of the lung.

Cigarette smoke extract induces DNA damage but not apoptosis in human bronchial epithelial cells

Whether DNA damage caused by cigarette smoke leads to repair or apoptosis has not been fully elucidated. The current study demonstrates that cigarette smoke induces single-strand DNA damage in human bronchial epithelial cells. Cigarette smoke also stimulated caspase 3 precursors as well as intact poly (ADP-ribose) polymerase (PARP) production, but did not activate caspase 3 or cleave PARP, while the alkaloid camptothecin did so. Neither apoptosis nor necrosis was induced by cigarette smoke when the insult was removed within a designated time period. In contrast, DNA damage following cigarette smoke exposure was repaired as evidenced by decreasing terminal dUTP-biotin nick-end labeling positivity. The PARP inhibitor, 3-aminobenzamide blocked this repair. Furthermore, cells subjected to DNA damage were able to survive and proliferate clonogenically when changed to smoke-free conditions. These results suggest that cigarette smoke-induced DNA damage in bronchial epithelial cells is not necessarily lethal, and that PARP functions in the repair process. Our data also suggest that the potency of cigarettes as a carcinogen may result from their ability to induce DNA damage while failing to trigger the apoptotic progression permitting survival of cells harboring potentially oncogenic mutations.

Aldehydes in cigarette smoke react with the lipid peroxidation product malonaldehyde to form fluorescent protein adducts on lysines

Cigarette smoke is a risk factor for the development of several diseases, but the exact mechanism responsible has not been well-characterized. Because modification, or adducting, of biomolecules is thought to mediate the toxic effects observed from exposure to a wide variety of harmful chemicals, this study investigated the ability of cigarette smoke to produce specific adducts on a peptide to gain insight into the likely effect on cellular proteins. We describe the modification of the epsilon-amino group of lysine contained in a test peptide with stable fluorescent adducts derived from monofunctional aldehydes occurring in cigarette smoke and malonaldehyde, a product of lipid peroxidation. Utilizing high-performance liquid chromatography, fluorescent measurements, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, the 1,4-dihydropyridine-3,5-dicarbaldehyde and 4-methyl-1,4-dihydropyridine-3,5-dicarbaldehyde derivatives of lysine were identified as products of exposure to cigarette smoke extract and malonaldehyde. These data suggest that cigarette smoke may promote the modification of proteins, like those associated with oxidized low-density lipoprotein, and may contribute to smoking-related disease.

Clinical Approach to Patients with Chronic Obstructive Pulmonary Disease and Cardiovascular Disease

It has long been recognized that reduced lung function is a major risk factor for cardiac death. It has also become clear that cardiac events are the major cause of death for patients with chronic obstructive pulmonary disease (COPD) with all stages of disease. These associations could be from shared risk factors, most notably cigarette smoking. However, there are mechanistic and physiologic relationships that could account for these associations. This raises the possibility that treatment of COPD could benefit cardiac risks. Despite this, the monitoring of lung function in cardiac patients is not routine. Neither is optimization of lung function, although it may greatly benefit exercise training designed to minimize cardiac risks and symptoms. Conversely, many patients with COPD are at greater risk for cardiac disease than may be recognized, because their COPD is often undiagnosed. Recognition of increased risk could impact the aggressiveness with which other risk factors, hypertension, and hypercholesterolemia are managed. Finally, the interactions between cardiac and pulmonary disease have important implications for the development of novel therapies. It is plausible that treatment of pulmonary inflammation characteristic of COPD will alter cardiac risk. Such an approach would offer a novel approach for the development of treatments for these common conditions.

Thrombin induces collagen gel contraction partially through PAR1 activation and PKC-epsilon

The ability of fibroblasts to contract three-dimensional collagen gels has been used as an in vitro model of the tissue contraction which characterises both normal repair and fibrosis. Among its actions, thrombin can activate the protease-activated receptor (PAR)1 and, thereby, stimulate inflammation and repair. The current study evaluated whether thrombin could stimulate fibroblast-mediated collagen gel contraction by activating PAR1 and whether its downstream signalling depends on protein kinase C (PKC)-epsilon. Human foetal lung fibroblasts (HFL-1) were cultured in three-dimensional collagen gels and the area of the gels was measured by image analyser. Both thrombin and TFLLR, a selective PAR1 agonist, stimulated collagen gel contraction mediated by HFL-1. After RNA interference-mediated PAR1 knockdown in HFL-1, both thrombin and the PAR1 agonist-induced gel contraction were partially inhibited (by 22.4+/-2.2% and 17.6+/-5.6%, respectively). The gel contraction stimulated by thrombin was also reduced by a nonspecific PKC inhibitor and a calcium-independent PKC-epsilon inhibitor. Both thrombin and TFLLR significantly increased PKC-epsilon activity, and this effect was blocked by PAR1 knockdown. Thrombin stimulates collagen gel contraction at least partially through activation of protease-activated receptor 1 and protein kinase C-epsilon, and may contribute to tissue remodelling in inflammatory airway and lung diseases.

Smad3 mediates TGF-β1 induction of VEGF production in lung fibroblasts

Transforming growth factor-beta1 (TGF-beta1) is a key factor in a variety of physiological and pathological processes. Vascular endothelial growth factor (VEGF) is a key angiogenic factor, and vascular change is one of the features of airway remodeling. We examined the effect of TGF-beta1 on VEGF production by fibroblasts from mice lacking expression of Smad2 or Smad3 as well as human lung fibroblasts treated with or without Smad2 or Smad3 siRNA. TGF-beta1 stimulated VEGF production by fibroblasts from Smad2 deficient animals and wildtype animals. In contrast, TGF-beta1 did not affect VEGF production by fibroblasts from Samd3 deficient mice. Similarly, TGF-beta1 failed to stimulate VEGF production by HFL-1 cells treated with Samd3 siRNA but significantly increased VEGF production by the cells treated with Smad2 siRNA. These result suggest that TGF-beta1 stimulation of VEGF production by fibroblasts is regulated by Smad3 but not by Smad2 signaling.

A prospective clinical study of theophylline safety in 3810 elderly with asthma or COPD

A large-scale prospective study was conducted in 3810 Japanese elderly (> or =65 years old) patients with asthma or chronic obstructive pulmonary disease (COPD) who had been treated with sustained-release theophylline tablets (THEODUR) at a dose of 400 mg/day for 1-6 months, in principle. Among 3798 protocol-complying patients (mean age: 73.8 +/- 0.10 years, 1997 with COPD), 261 theophylline-related adverse events were observed in 179 (4.71%) patients. The 5 most frequently observed adverse events were "nausea" (40 episodes, 1.05%), "loss of appetite" (22 episodes, 0.56%), "hyperuricemia" (16 episodes, 0.42%), "palpitation" (15 episodes, 0.39%), and "increased alkaline phosphatase" (11 episodes, 0.28%). No convulsions were reported. Six patients had serious adverse events. The incidence of theophylline-related adverse events was higher in patients with hepatic disease (odds ratio: 1:1.81) and in patients with arrhythmia (odds ratio: 1:1.88). Blood drug concentration measurements in 736 patients indicated that the drug levels were < or =15 microg/ml in 641 patients (87.1%), and no correlation was noted between dose and theophylline-related adverse events. These results suggest that sustained-release theophylline can be used safely in elderly patients with asthma or COPD.

Cells Derived from the Circulation Contribute to the Repair of Lung Injury

Bone marrow (stem/progenitor) cells have been shown to "differentiate" into cells in multiple tissues, including lung. A low number of hematopoietic stem/progenitor cells also circulate in peripheral blood. The physiologic roles of these cells are still uncertain. This study was designed to test, using parabiotic mice that were joined surgically, whether stem/progenitor cells in blood contributed to the regeneration of lung after injury. Parabiotic mice were generated surgically by joining green fluorescent protein transgenic mice and wild-type littermates. These mice developed a common circulation (approximately 50% green cells in blood) by 2 weeks after surgery. The wild-type mouse was either uninjured or lethally irradiated or received intratracheal elastase or the combination of radiation with intratracheal elastase injection. Radiation or the combination of radiation with elastase significantly increased the proportion of bright green cells in the lungs of the wild-type mice. Morphologically, interstitial monocytes/macrophages, subepithelial fibroblast-like interstitial cells, and additionally type I alveolar epithelial cells immunostained for green fluorescent protein in wild-type mice. Approximately 5 to 20% of lung fibroblasts primary cultured from injured wild-type mice were green fluorescent protein expressing cells, indicating their blood derivation. This study demonstrates that stem/progenitor cells in blood contribute to the repair of lung injury in irradiated mice.