Prolonged, physiologically relevant nicotine concentrations in the airways of smokers

Nicotine from cigarette smoke is a biologically active molecule that has pleiotropic effects in the airway, which could play a role in smoking-induced lung disease. However, whether nicotine and its metabolites reach sustained, physiologically relevant concentrations on airway surfaces of smokers is not well defined. To address these issues, concentrations of nicotine, cotinine, and hydroxycotinine were measured by mass spectrometry (MS) in supernatants of induced sputum obtained from participants in the subpopulations and intermediate outcome measures in COPD study (SPIROMICS), an ongoing observational study that included never smokers, former smokers, and current smokers with and without chronic obstructive pulmonary disease (COPD). A total of 980 sputum supernatants were analyzed from 77 healthy never smokers, 494 former smokers (233 with COPD), and 396 active smokers (151 with COPD). Sputum nicotine, cotinine, and hydroxycotinine concentrations corresponded to self-reported smoking status and were strongly correlated to urine measures. A cutoff of ∼8-10 ng/mL of sputum cotinine distinguished never smokers from active smokers. Accounting for sample dilution during processing, active smokers had airway nicotine concentrations in the 70-850 ng/mL (∼0.5-5 µM) range, and concentrations remained elevated even in current smokers who had not smoked within 24 h. This study demonstrates that airway nicotine and its metabolites are readily measured in sputum supernatants and can serve as biological markers of smoke exposure. In current smokers, nicotine is present at physiologically relevant concentrations for prolonged periods, supporting a contribution to cigarette-induced airway disease.

Genetic variation in genes regulating skeletal muscle regeneration and tissue remodelling associated with weight loss in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. COPD patients with cachexia or weight loss have increased risk of death independent of body mass index (BMI) and lung function. We tested the hypothesis genetic variation is associated with weight loss in COPD using a genome-wide association study approach.

METHODS

Participants with COPD (N = 4308) from three studies (COPDGene, ECLIPSE, and SPIROMICS) were analysed. Discovery analyses were performed in COPDGene with replication in SPIROMICS and ECLIPSE. In COPDGene, weight loss was defined as self-reported unintentional weight loss > 5% in the past year or low BMI (BMI < 20 kg/m2 ). In ECLIPSE and SPIROMICS, weight loss was calculated using available longitudinal visits. Stratified analyses were performed among African American (AA) and Non-Hispanic White (NHW) participants with COPD. Single variant and gene-based analyses were performed adjusting for confounders. Fine mapping was performed using a Bayesian approach integrating genetic association results with linkage disequilibrium and functional annotation. Significant gene networks were identified by integrating genetic regions associated with weight loss with skeletal muscle protein-protein interaction (PPI) data.

RESULTS

At the single variant level, only the rs35368512 variant, intergenic to GRXCR1 and LINC02383, was associated with weight loss (odds ratio = 3.6, 95% confidence interval = 2.3-5.6, P = 3.2 × 10-8 ) among AA COPD participants in COPDGene. At the gene level in COPDGene, EFNA2 and BAIAP2 were significantly associated with weight loss in AA and NHW COPD participants, respectively. The EFNA2 association replicated among AA from SPIROMICS (P = 0.0014), whereas the BAIAP2 association replicated in NHW from ECLIPSE (P = 0.025). The EFNA2 gene encodes the membrane-bound protein ephrin-A2 involved in the regulation of developmental processes and adult tissue homeostasis such as skeletal muscle. The BAIAP2 gene encodes the insulin-responsive protein of mass 53 kD (IRSp53), a negative regulator of myogenic differentiation. Integration of the gene-based findings participants with PPI data revealed networks of genes involved in pathways such as Rho and synapse signalling.

CONCLUSIONS

The EFNA2 and BAIAP2 genes were significantly associated with weight loss in COPD participants. Collectively, the integrative network analyses indicated genetic variation associated with weight loss in COPD may influence skeletal muscle regeneration and tissue remodelling.

IGSF3 mutation identified in patient with severe COPD alters cell function and motility

Cigarette smoking (CS) and genetic susceptibility determine the risk for development, progression, and severity of chronic obstructive pulmonary diseases (COPD). We posited that an incidental balanced reciprocal chromosomal translocation was linked to a patient's risk of severe COPD. We determined that 46,XX,t(1;4)(p13.1;q34.3) caused a breakpoint in the immunoglobulin superfamily member 3 (IGSF3) gene, with markedly decreased expression. Examination of COPDGene cohort identified 14 IGSF3 SNPs, of which rs1414272 and rs12066192 were directly and rs6703791 inversely associated with COPD severity, including COPD exacerbations. We confirmed that IGSF3 is a tetraspanin-interacting protein that colocalized with CD9 and integrin B1 in tetraspanin-enriched domains. IGSF3-deficient patient-derived lymphoblastoids exhibited multiple alterations in gene expression, especially in the unfolded protein response and ceramide pathways. IGSF3-deficient lymphoblastoids had high ceramide and sphingosine-1 phosphate but low glycosphingolipids and ganglioside levels, and they were less apoptotic and more adherent, with marked changes in multiple TNFRSF molecules. Similarly, IGSF3 knockdown increased ceramide in lung structural cells, rendering them more adherent, with impaired wound repair and weakened barrier function. These findings suggest that, by maintaining sphingolipid and membrane receptor homeostasis, IGSF3 is required for cell mobility-mediated lung injury repair. IGSF3 deficiency may increase susceptibility to CS-induced lung injury in COPD.

Ventricular Geometry From Non-contrast Non-ECG-gated CT Scans: An Imaging Marker of Cardiopulmonary Disease in Smokers

RATIONALE AND OBJECTIVES

Imaging-based assessment of cardiovascular structure and function provides clinically relevant information in smokers. Non-cardiac-gated thoracic computed tomographic (CT) scanning is increasingly leveraged for clinical care and lung cancer screening. We sought to determine if more comprehensive measures of ventricular geometry could be obtained from CT using an atlas-based surface model of the heart.

MATERIALS AND METHODS

Subcohorts of 24 subjects with cardiac magnetic resonance imaging (MRI) and 262 subjects with echocardiography were identified from COPDGene, a longitudinal observational study of smokers. A surface model of the heart was manually initialized, and then automatically optimized to fit the epicardium for each CT. Estimates of right and left ventricular (RV and LV) volume and free-wall curvature were then calculated and compared to structural and functional metrics obtained from MRI and echocardiograms.

RESULTS

CT measures of RV dimension and curvature correlated with similar measures obtained using MRI. RV and LV volume obtained from CT inversely correlated with echocardiogram-based estimates of RV systolic pressure using tricuspid regurgitation jet velocity and LV ejection fraction respectively. Patients with evidence of RV or LV dysfunction on echocardiogram had larger RV and LV dimensions on CT. Logistic regression models based on demographics and ventricular measures from CT had an area under the curve of >0.7 for the prediction of elevated right ventricular systolic pressure and ventricular failure.

CONCLUSIONS

These data suggest that non-cardiac-gated, non-contrast-enhanced thoracic CT scanning may provide insight into cardiac structure and function in smokers.

Trolox contributes to Nrf2-mediated protection of human and murine primary alveolar type II cells from injury by cigarette smoke

Cigarette smoke (CS) is a main risk factor for chronic obstructive pulmonary disease (COPD). Oxidative stress induced by CS causes DNA and lung damage. Oxidant/antioxidant imbalance occurs in the distal air spaces of smokers and in patients with COPD. We studied the effect of oxidative stress generated by CS both in vivo and in vitro on murine primary alveolar type II (ATII) cells isolated from nuclear erythroid 2-related factor-2 (Nrf2)(-/-) mice. We determined human primary ATII cell injury by CS in vitro and analyzed ATII cells isolated from smoker and non-smoker lung donors ex vivo. We also studied whether trolox (water-soluble derivative of vitamin E) could protect murine and human ATII cells against CS-induced DNA damage and/or decrease injury. We analyzed oxidative stress by 4-hydroxynonenal expression, reactive oxygen species (ROS) generation by Amplex Red Hydrogen Peroxide Assay, Nrf2, heme oxygenase 1, p53 and P53-binding protein 1 (53BP1) expression by immonoblotting, Nrf2 nuclear translocation, Nrf2 and p53 DNA-binding activities, apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and cytokine production by ELISA. We found that ATII cells isolated from Nrf2(-/-) mice are more susceptible to CS-induced oxidative DNA damage mediated by p53/53BP1 both in vivo and in vitro compared with wild-type mice. Therefore, Nrf2 activation is a key factor to protect ATII cells against injury by CS. Moreover, trolox abolished human ATII cell injury and decreased DNA damage induced by CS in vitro. Furthermore, we found higher inflammation and p53 mRNA expression by RT-PCR in ATII cells isolated from smoker lung donors in comparison with non-smokers ex vivo. Our results indicate that the Nrf2 and p53 cross talk in ATII cells affect the susceptibility of these cells to injury by CS. Trolox can protect against oxidative stress, genotoxicity and inflammation induced by CS through ROS scavenging mechanism, and serve as a potential antioxidant prevention strategy against oxidative injury of ATII cells in CS-related lung diseases.

SELDI-TOF derived serum biomarkers failed to differentiate between patients with beryllium sensitisation and patients with chronic beryllium disease

BACKGROUND

People exposed to beryllium may develop beryllium sensitisation (BeS) and, in some cases, progress to chronic beryllium disease (CBD).

OBJECTIVES

The objective of this study was to test the ability of proteomic technology to identify patterns of serum protein biomarkers that allow differentiation between BeS and CBD and thus remove the need for invasive bronchoscopic procedures.

METHODS

Initially, SELDI-TOF methodology and analysis was performed on serum samples from 30 CBD and 31 BeS patients.

RESULTS

This 'starter set' yielded two distinct biomarker pattern sets with eight candidate proteins. The first set differentiated between BeS and CBD with 83.3% sensitivity and 82.3% specificity, with 10-fold cross-validation of 75% and 79%, respectively. The second set of biomarkers yielded higher sensitivity (90.0%) and higher specificity (90.3%), with 10-fold cross-validation of 71.7% and 82.3%, respectively. Due to its greater sensitivity and specificity, the second set of biomarkers was used as the framework for differentiating between CBD and BeS in a second set of serum samples from 450 patients with BeS and CBD. When this larger set of samples was subjected to the biomarker framework in a blinded fashion, it yielded a sensitivity of 43.53% and a specificity of 38.93%.

CONCLUSIONS

Due to these low sensitivity and specificity values, we have concluded that, currently, the unique set of SELDI-TOF derived biomarkers does not possess the qualities that would allow it to differentiate between a CBD patient and a BeS patient using serum protein biomarkers. Future refinements in sample collection or proteomic technology may be needed to improve biomarker discovery.

Tumour necrosis factor gene polymorphisms are associated with COPD

Tumour necrosis factor (TNF)-alpha has been shown to be an important factor in animal models of chronic obstructive pulmonary disease (COPD). However, human studies of TNF polymorphisms in COPD have been equivocal. Six TNF single nucleotide polymorphisms (-1031C/T, -863C/A, -857C/T, -237G/A, -308G/A and +487G/A) and their haplotypes were investigated in 423 Caucasian smokers (298 patients with spirometric evidence of COPD and 125 without airflow obstruction). The -308 minor allele (A) had a higher odds ratio (OR) of being associated with COPD in multivariate analysis (controlling for age, sex, pack-yrs; OR 1.9, 95% confidence interval (CI) 1.1-3.2) and was also associated with worse forced expiratory volume in one second/forced vital capacity. The -237 minor allele (A) had a lower OR of being associated with COPD (OR 0.40, 95% CI 0.19-0.86). In COPD patients, the -857 minor allele (T) had a lower OR of being associated with severe stages of COPD (Global Initiative for Obstructive Lung Disease stage III and IV versus stage I and II, OR 0.46, 95% CI 0.24-0.88). Other TNF single nucleotide polymorphisms were not associated with COPD but the -1031/-863 haplotype CC/TC had a lower OR in COPD patients versus smoking controls (OR 0.22, 95% CI 0.05-0.97). The present study adds further evidence that tumour necrosis factor genotypes play a role in susceptibility to cigarette smoke.

Joint fluid antioxidants are decreased in osteoarthritic joints compared to joints with macroscopically intact cartilage and subacute injury

OBJECTIVE

Excess reactive oxygen species and oxidative damage have been associated with the pathogenesis of osteoarthritis (OA). Extracellular superoxide dismutase (EC-SOD or SOD3) scavenges superoxide is the major catalytic antioxidant in joint fluid and is decreased in OA cartilage. We studied human joint fluid samples to test whether there is an association between OA and EC-SOD or other low molecular antioxidants in the joint fluid.

METHODS

Joint fluid samples were obtained from 28 subjects with severe OA undergoing arthrocentesis or knee joint replacement and compared to joint fluid from 12 subjects undergoing knee arthroscopy for chronic knee pain, meniscal tears or anterior cruciate ligament reconstruction. EC-SOD protein was assayed by enzyme-linked immunosorbent assay (ELISA). Ascorbate and urate were measured with high performance liquid chromatography (HPLC) and total nitrates by the Greiss reaction. Glutathione (GSH) and oxidized glutathione were measured using a colorimetric method. Interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta) were both measured with ELISA.

RESULTS

Human joint fluid contains significant amounts of the extracellular, catalytic antioxidant EC-SOD. Joint fluid from OA subjects is characterized by significantly decreased EC-SOD levels and significant decreases in GSH, and ascorbate compared to the reference group of knee joints with pain or subacute injury but macroscopically intact cartilage. GSH and ascorbate show only an age effect with no effect from disease state on regression modeling. Urate is present in joint fluid but does not show a significant difference between groups. IL-6 and TGF-beta both show non-significant trends to increases in the arthritic subjects. There was no correlation of EC-SOD levels with IL-6 as a marker of inflammation in either the comparison group or the OA group.

CONCLUSIONS

EC-SOD, the major scavenger of reactive oxygen species (ROS) in extracellular spaces and fluids, is decreased in late stage OA joint fluid compared to fluid from injured/painful joints with intact cartilage. Injured joints may be able to increase or maintain secretion of EC-SOD but it appears that late stage OA joints fail to do so in spite of increased oxidative stress seen in the disease. Associated age related declines in GSH and ascorbate might also contribute to the development of severe OA. The net effect of these changes in joint fluid antioxidants is likely to accelerate the damaging oxidant effects on extracellular matrix stability in cartilage tissue.

The intracellular proteolytic processing of extracellular superoxide dismutase (EC-SOD) is a two-step event

Extracellular superoxide dismutase (EC-SOD) is a tetramer composed of either intact (Trp(1)-Ala(222)) or proteolytically cleaved (Trp(1)-Glu(209)) subunits. The latter form is processed intracellularly before secretion and lacks the C-terminal extracellular matrix (ECM)-binding region ((210)RKKRRRESECKAA(222)-COOH). We have previously suggested that the C-terminal processing of EC-SOD is either a one-step mechanism accomplished by a single intracellular endoproteolytic event cleaving the Glu(209)-Arg(210) peptide bond or a two-step mechanism involving two proteinases (Enghild, J. J., Thogersen, I. B., Oury, T. D., Valnickova, Z., Hojrup, P., and Crapo, J. D. (1999) J. Biol. Chem. 274, 14818-14822). In the latter case, an initial endoproteinase cleavage occurs somewhere in the region between Glu(209) and Glu(216). A carboxypeptidase specific for basic amino acid residues subsequently trims the remaining basic amino acid residues to Glu(209). A naturally occurring mutation of EC-SOD substituting Arg(213) for Gly enabled us to test these hypotheses. The mutation does not prevent proteolysis of the ECM-binding region but prevents a carboxypeptidase B-like enzyme from trimming residues beyond Gly(213). The R213G mutation is located in the ECM-binding region, and individuals carrying this mutation have an increased concentration of EC-SOD in the circulatory system. In this study, we purified the R213G EC-SOD variant from heterozygous or homozygous individuals and determined the C-terminal residue of the processed subunit to be Gly(213). This finding supports the two-step processing mechanism and indicates that the R213G mutation does not disturb the initial endoproteinase cleavage event but perturbs the subsequent trimming of the C terminus.

Extracellular superoxide dismutase attenuates lung injury after hemorrhage

Reperfusion of the lung after hemorrhage generates free radicals such as superoxide (O(2)(.)) that may injure the lung; however, the relative importance of intracellular versus extracellular free radicals is unclear. The superoxide dismutases (SOD) are the primary enzymatic method to reduce superoxide. We examined whether lung-specific overexpression of extracellular superoxide dismutase (EC-SOD) would attenuate hemorrhage-induced lung injury. Wild-type mice and mice overexpressing the human EC-SOD gene with a lung-specific promoter were hemorrhaged by removing 30% of blood volume. After hemorrhage, the lung wet to dry weight ratios increased from 5.4 +/- 0.11 in unmanipulated control mice to 6.3 +/- 0.16 in wild-type mice, but to only 5.60 +/- 0.17 in the EC-SOD transgenic mice (p < 0.05 compared with hemorrhaged wild-type). Hemorrhage-induced lipid peroxidation, as assessed by lung F(2) isoprostanes, was lower in the EC-SOD transgenic mice (3.4 +/- 0.3 microg/lung) compared with wild-type mice (1.9 +/- 0.2 microg/lung; p < 0.05). Compared with wild-type, EC-SOD transgenic mice had attenuated the hemorrhage-induced increase in both pulmonary nuclear factor kappa B (NK-kappaB) activation (relative absorbance 1.1 +/- 0.2 for EC-SOD transgenic versus 2.5 +/- 0.1 for wild-type; p < 0.05) and myeloperoxidase activity (5.1 +/- 0.87 units/g for EC-SOD transgenic versus 11.3 +/- 1.8 units/g for wild-type; p < 0.01). Thus, overexpression of pulmonary EC-SOD in the mouse lung attenuates lung injury after hemorrhage.

Isolated pulmonary capillaritis and diffuse alveolar hemorrhage in rheumatoid arthritis and mixed connective tissue disease

STUDY OBJECTIVES

To demonstrate that pulmonary capillaritis and diffuse alveolar hemorrhage (DAH) occur and are isolated to the lung and therefore not part of systemic vasculitis at the time of the DAH episode in rheumatoid arthritis (RA) and mixed connective tissue disease (MCTD).

DESIGN

Lung biopsy specimens from patients with DAH were reviewed and those with the histologic features of pulmonary capillaritis were identified.

SETTING

The patients were selected from seven Denver-area general hospitals.

PATIENTS

Fifty-eight patients with biopsy specimen proved pulmonary capillaritis (1991 to 1997) were identified and classified according to disease. Three patients met the American Rheumatism Association criteria for RA and one patient fulfilled clinical and serologic criteria for MCTD.

INTERVENTIONS

All clinical, laboratory, and radiographic data on initial presentation and at follow-up periods were extracted from the charts of the four study patients. Histologic slides were reviewed and immunofluorescent studies of lung tissue were performed.

MEASUREMENTS AND RESULTS

All four patients had a connective tissue disease diagnosis prior to the DAH episode. Symptoms referable to pulmonary capillaritis were of short duration (2 to 14 days) and there was no clinical or serologic evidence for an accompanying systemic vasculitis, in particular glomeronephritis. Three patients, two with RA and one with MCTD, demonstrated pulmonary immune complex deposition. Three resolved their illness following IV methylprednisilone and cyclophosphamide therapy. One RA patient died following a myocardial infarction. In the three survivors, no further episodes of DAH have occurred after a mean of 24 months (range, 10 to 48 months).

CONCLUSIONS

To our knowledge, these are the first cases of DAH due to pulmonary capillaritis documented to complicate RA and MCTD. The capillaritis was not part of a systemic vasculitis at the time of the DAH episode, but rather represented an isolated small-vessel vasculitis of the lungs in this group of patients. Immune complex deposition may be involved in the pathogenesis.

Massive hemoptysis from a pulmonary artery aneurysm associated with an emphysematous bulla

A 66-year-old man with a history of COPD and Aspergillus fumigatus infection developed massive hemoptysis. Pulmonary artery angiography revealed an aneurysm which was successfully treated with coil embolization. This is the first known report of a pulmonary artery aneurysm causing massive hemoptysis in a patient with bullous emphysema.

Stability of psychological impairment: two year follow-up of former microelectronics workers' affective and personality disturbance

For the past twenty years women's complaints in the microelectronics industry have often been diagnosed as mass psychogenic illness, despite evidence of potential exposure to organic solvents, which have been associated with affect and mood changes. In the present study, the standard version of the Minnesota Multiphasic Personality Inventory (MMPI) was used to evaluate affective and personality disturbance among 63 former microelectronics workers (56 women and 7 men) over a two-year period of time. In both 1986 and 1988, the former workers obtained mean scale score elevations beyond two standard deviations above the normative sample (T = greater than 70) on the MMPI clinical scales of schizophrenia, hypochondriasis, psychasthenia, depression and hysteria. For most scales, 86-88 mean score differences did not attain the 0.05 significance level (two-tailed paired t-test) and no significant differences were observed for 86-88 comparison scale scores = greater than 70 (McNemar paired statistic). Although there were too few men to perform gender comparisons, men scored higher than women on 5 scales and all of the men had scores = greater than 70 on hypochondriasis, depression, hysteria, psychasthenia and schizophrenia. These findings reveal that these former microelectronics workers manifested affective and personality disturbances, consistent with organic solvent toxicity, which persisted over a two year period, indicating that they were not reactive, transient hysterical neurosis.

Computer searching for occupational medicine

Occupational and environmental medical literature that confronts a physician is difficult to grasp. The development of the microcomputer makes it easier for the occupational medicine physician to perform computer literature searches. Occupational medical residents and physicians both familiar and unfamiliar with computers submitted identical searches to identify strengths and weaknesses of combinations of computer databases and assisting software. The combination of DIALOG databases and In-Search software were judged to be the most useful for the occupational medicine physician.