Day-night variations in endothelial dysfunction markers and haemostatic factors in sleep apnoea.

Patients with sleep apnoea have a significant alteration in the day-night pattern of myocardial infarction and sudden cardiac death observed in the general population. The aim of this study was to investigate the influence of sleep apnoea on the diurnal variations in various haemostatic parameters (factor VII, von Willebrand factor and plasminogen activator inhibitor (PAI)-1) and markers of endothelial dysfunction (asymmetric dimethylarginine (ADMA) and soluble CD40 ligand (sCD40L)). We studied 26 male patients with obstructive sleep apnoea syndrome (OSAS; 13 patients with severe OSAS (apnoea/hypopnoea index (AHI) >30 events · h(-1)) and 13 patients with mild-to-moderate OSAS (AHI <30 events · h(-1))) and 12 controls of similar body mass index (BMI) and waist circumference. In each subject, six different samples were obtained over 24 h. Although all the markers values tended to be higher in patients with severe OSAS, differences did not reach statistical significance at any time. PAI-1 levels were significantly related to BMI (p<0.001), mean (p<0.001) and minimal (p = 0.047) nocturnal oxygenation saturation. ADMA levels were significantly related to arousal index (p = 0.046). The results of this study suggest that day-night variations in factor VII:antigen (Ag), von Willebrand factor:Ag, PAI-1, sCD40L and ADMA levels may be dependent on either the obesity index or metabolic dysfunction rather than on sleep apnoea alone.

Candidate genes for COPD in two large data sets.

Lack of reproducibility of findings has been a criticism of genetic association studies on complex diseases, such as chronic obstructive pulmonary disease (COPD). We selected 257 polymorphisms of 16 genes with reported or potential relationships to COPD and genotyped these variants in a case-control study that included 953 COPD cases and 956 control subjects. We explored the association of these polymorphisms to three COPD phenotypes: a COPD binary phenotype and two quantitative traits (post-bronchodilator forced expiratory volume in 1 s (FEV1) % predicted and FEV1/forced vital capacity (FVC)). The polymorphisms significantly associated to these phenotypes in this first study were tested in a second, family-based study that included 635 pedigrees with 1,910 individuals. Significant associations to the binary COPD phenotype in both populations were seen for STAT1 (rs13010343) and NFKBIB/SIRT2 (rs2241704) (p<0.05). Single-nucleotide polymorphisms rs17467825 and rs1155563 of the GC gene were significantly associated with FEV1 % predicted and FEV1/FVC, respectively, in both populations (p<0.05). This study has replicated associations to COPD phenotypes in the STAT1, NFKBIB/SIRT2 and GC genes in two independent populations, the associations of the former two genes representing novel findings.

Lipopolysaccharide-binding protein and CD14 are increased in the bronchoalveolar lavage fluid of smokers.

Lipopolysaccharide-binding protein (LBP) and CD14 contribute to the recognition of pathogens by cells, which triggers the activation of defence responses. Smoking is a risk factor for the development of chronic obstructive pulmonary disease (COPD) and respiratory infections. The current authors theorised that levels of LBP and CD14 in the lungs of smokers would be higher than those in the lungs of never-smokers. These elevated levels could affect host responses upon infection. LBP, soluble CD14 (sCD14) and interleukin (IL)-8 were detected by ELISA. Nuclear factor (NF)-kappaB, p38 and the inhibitor IkappaBalpha were studied by immunoassays. Gene expression was assessed by RT-PCR. Bronchoalveolar lavage levels of LBP and CD14 were significantly higher in smokers and COPD patients than in never-smokers, whereas levels of both proteins were not significantly different between smokers and COPD patients. IL-6, IL-1beta and cigarette smoke condensate induced the expression of LBP and CD14 by airway epithelial cells. LBP and sCD14 inhibited the nontypeable Haemophilus influenzae (NTHi)-dependent secretion of IL-8 and the activation of NF-kappaB and p38 mitogen-activated protein kinase signalling pathways but they increased the internalisation of NTHi by airway epithelial cells. Thus, in the inflamed airways of smokers both proteins could contribute to inhibit bacteria-dependent cellular activation without compromising the internalisation of pathogens by airway cells.

Insulin resistance and daytime sleepiness in patients with sleep apnoea.

BACKGROUND: Excessive daytime sleepiness (EDS), obesity and insulin resistance (IR) occur frequently in patients with obstructive sleep apnoea syndrome (OSAS). We hypothesised that in these patients, EDS is a marker of IR, independent of obesity. METHODS: We studied 44 patients with OSAS (22 with and 22 without EDS) matched for age (+/-5 years), body mass index (BMI +/-3 kg/m(2)) and severity of OSAS (as determined by the apnoea-hypopnoea index (AHI)), and 23 healthy controls. Patients (n = 35) were re-examined after 3 months of effective therapy with continuous positive airway pressure (CPAP). EDS was assessed by both subjective (Epworth Sleepiness Scale) and objective (Multiple Sleep Latency Test) methods. IR was determined by the HOMA index. Serum levels of glucose, triglycerides, cholesterol, cortisol, insulin, thyrotropin, growth hormone and insulin-like growth factor I (IGF-I) were also determined. RESULTS: Despite the fact that age, BMI and AHI were similar, patients with EDS had higher plasma levels of glucose (p<0.05) and insulin (p<0.01), as well as evidence of IR (p<0.01) compared with patients without EDS or healthy controls. CPAP treatment reduced cholesterol, insulin and the HOMA index and increased IGF-1 levels in patients with EDS, but did not modify any of these variables in patients without EDS. CONCLUSION: EDS in OSAS is associated with IR, independent of obesity. Hence EDS may be a useful clinical marker to identify patients with OSAS at risk of metabolic syndrome.

Phenotypic characterisation of T-lymphocytes in COPD: abnormal CD4+CD25+ regulatory T-lymphocyte response to tobacco smoking.

Tobacco smoking induces an inflammatory response in the lungs of all smokers but, for reasons that are still poorly understood, only a proportion of them develop chronic obstructive pulmonary disease (COPD). Recent evidence indicates that this inflammatory response persists after smoking cessation, suggesting some type of auto-perpetuation mechanism similar to that described in autoimmune disorders. T-lymphocytes (CD4+ and CD8+) have been implicated in the pathogenesis of both COPD and several autoimmune processes. A subtype of regulatory CD4+ T-cells expressing CD25 (Tregs) plays a critical role in the maintenance of peripheral tolerance and the prevention of autoimmunity, but their potential role in COPD has not been explored. The present study sought to evaluate maturation (CD45RA/CD45R0) and activation markers (CD28) of T-lymphocytes and to explore potential Treg abnormalities in COPD. Flow cytometry was used to characterise T-lymphocytes obtained from blood and bronchoalveolar lavage fluid (BALF) in 23 patients with moderate COPD, 29 smokers with normal lung function and seven never-smokers. The main findings were that in BALF: patients with COPD showed higher CD8+CD45RA+ and lower CD8+CD45R0+ than smokers with normal lung function; and compared with never-smokers, smokers with preserved lung function showed a prominent upregulation of Tregs that was absent in patients with COPD. These observations indicate a final maturation-activation state of CD8+ T-lymphocytes in chronic obstructive pulmonary disease and, for the first time, identify a blunted regulatory T-cell response to tobacco smoking in these patients, further supporting a potential involvement of the acquired immune response in the pathogenesis of the disease.

Reflections on TORCH: potential mechanisms for the survival benefit of salmeterol/fluticasone propionate in COPD patients.

COPD is a disease with a multi-component pathophysiology in which inflammation plays a key role. An anti-inflammatory effect of salmeterol (S)/fluticasone propionate (FP) combination (SFC), as demonstrated in a number of biopsy studies, may be the mechanism by which it provides a potential survival benefit in COPD patients in the TORCH study. It is possible that the molecular synergy between S and FP shown in COPD results in enhanced anti-inflammatory in the airways. This may also contribute to the reduction in exacerbations and the increase in lung function seen in the TORCH study. Alternatively, SFC may prolong survival by impacting on systemic inflammation and disease co-morbidities in COPD.

Prostaglandin D synthase (beta trace) levels in sleep apnea patients with and without sleepiness.

BACKGROUND: Excessive daytime sleepiness (EDS) occurs often in patients with obstructive sleep apnea syndrome (OSAS). However, not all patients present EDS. We hypothesized that the prostaglandin D2 system (PGD2) may be involved in the pathogenesis of EDS associated with OSAS. METHODS: We measured the levels of lipocalin-type PGD synthase (L-PGDS), the enzyme that produces PGD2, in the serum of 47 patients with OSAS (26 with and 21 without EDS) and 18 healthy controls. RESULTS: Patients with EDS had higher levels of L-PGDS (0.73+/-0.06 mg/L) than patients without EDS (0.58+/-0.03 mg/L, p<0.05) and controls (0.62+/-0.02 mg/L, p<0.05). L-PGDS levels in patients without EDS and controls were similar. CONCLUSION: The increased levels of circulating L-PGDS detected in OSAS patients with EDS suggest a possible role of the prostaglandin D system in the pathophysiology of daytime sleepiness in these patients.

COPD, a multicomponent disease: implications for management.

Chronic obstructive pulmonary disease (COPD) is a multicomponent disease. These components affect both the lungs and organs outside the lungs (the so-called systemic effects of COPD) and can be of either a structural (including airway remodelling, emphysema, skeletal muscle wasting) or functional nature (inflammation, apoptosis, senescence). Further, these components are interdependent in a closely linked 'vicious cycle'. Accordingly, optimal therapies should therefore aim to address more than one of these components to break such a cycle. This needs to be considered not only in the development of future treatments but also in the current clinical management of patients with COPD. In this paper, evidence that supports the concept that COPD is a multicomponent disease is presented. The effects of currently available therapeutic options, including long-acting anticholinergics and long-acting beta2-agonist/inhaled corticosteroid combination therapies, upon each of these components is reviewed. In addition, potential new avenues for drug development and improved patient care are highlighted. By developing a better understanding of how different therapies impact upon the 'vicious cycle' of COPD, treatment regimens can be optimised to provide the greatest benefits to patients.

Plasminogen activator inhibitor-I (PAI-I) polymorphisms in patients with obstructive sleep apnoea.

Cardiovascular diseases are frequent among patients with the obstructive sleep apnoea syndrome (OSAS), The aetiopathogenesis of this association is unclear. Type 1 plasminogen activator inhibitor (PAI-1) is one of the primary regulators of the fibrinolytic system. A reported association between PAI-1 activity and an insertion/deletion polymorphism (4G/5G) in the promoter region of the PAI-1 gene suggests a critical role for this genomic region in the pathogenesis of several cardiovascular diseases. In this study, we determined the prevalence of this polymorphism in patients with OSAS and in healthy control subjects. The 4G/5G polymorphism in the promoter region of the PAI-1 gene was determined in 78 male patients with severe OSAS (56 +/- 2 apnoeas per hour) and in 70 healthy male, non-smoker volunteers of similar age, without personal or familial history of cardiovascular disease. The frequency ofthe 4G/4G, 4G/5G and 5G/5G genotypes in patients with OSAS (18%, 62%, 19%, respectively) was not significantly different from that seen in healthy subjects (16%, 60%, 24% P=NS). These results show that the distribution of the 4G/5G polymorphism in the promoter region ofthe PAI-1 gene in patients with OSAS is similar to that observed in healthy subjects. This observation suggests that the PAI-1 polymorphism has no relationship with the increased risk of cardiovascular diseases seen in patients with OSAS.

[Steady car engine noise does not affect the cognitive abilities of sleep apnea syndrome patients]. / El ruido monótono no afecta a las capacidades cognitivas en pacientes con síndrome de apnea del sueño.

Traffic accidents are more frequent for sleep apnea syndrome (SAS) patients than in the population at large. The mechanisms that underlie this observation are poorly defined. Our working hypothesis was that in SAS patients the steady noise of a car engine might alter cognitive capacities that may be involved in driving, thus increasing the risk of traffic accidents. To test this hypothesis we designed a prospective randomized controlled trial. Eighteen SAS patients (apnea-hypopnea index [SEM] 62 [6] h1) and 18 healthy controls were studied. All the participants were evaluated in random order both in basal conditions and after exposure to the steady noise of a car engine recorded on a compact disc. Their level of vigilance was evaluated (Steer-Clear) as well as their reaction time (PVT 192). Attention, coordination, and memory were measured using the following tests: Wechsler Memory Scale (digit span), the Wechsler Intelligence Scale (digit symbol), and Lezack's Trail Making tests A and B. The SAS patients were slightly younger than the control group (mean 50 [7] vs 57 [11] years, respectively; P=.05). The patients showed a lower level of vigilance than the controls both in basal and engine noise conditions (P<.05). No differences between groups were found for the other variables studied. Exposure to steady car engine noise had no effect on the tests of either group. In conclusion, the results of our study do not support the hypothesis that steady car engine noise significantly alters the cognitive ability of SAS patients.

[Systemic inflammation during exacerbations of chronic obstructive pulmonary disease]. / Inflamación sistémica durante las agudizaciones de la enfermedad pulmonar obstructiva crónica.

OBJECTIVE: The circulating blood levels of several inflammatory cytokines and acute phase proteins are higher in patients with stable chronic obstructive pulmonary disease (COPD). However, whether or not these inflammatory markers increase during COPD exacerbation or are modified by corticosteroid treatment has not been investigated. The objective of this study was therefore 1) to describe changes in several inflammatory markers in systemic circulation during COPD exacerbation, and 2) to assess the potential effects of corticosteroid treatment during exacerbation. METHODS: Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), interleukin 8 (IL-8) and C-reactive protein (CRP) were determined for 10 patients (65 2 years old) with severe COPD (FEV1 35 4% reference) who were hospitalized for acute respiratory failure (PaO2 57 2 mm Hg; PaCO2 48 3 mm Hg). Blood samples were obtained in the emergency room (before starting intravenous corticosteroid treatment), during the first 24 hours of admission, upon discharge and two months later. Eight healthy non-smokers of a similar age (54 3 years) were also studied as control subjects. RESULTS: The COPD patients had higher concentrations of IL-6 (5.1 1.6 vs. 1.8 0.5 pg/mL, p < 0.05) and CRP (2.2 0.4 vs. 0.6 0.2 mg/dL, p < 0.005) than did controls, but the concentrations of IL-8 were similar (29 11.3 vs. 34.7 10.3 pg/mL, p = ns). No statistically significant changes were seen either during recovery, in spite of intravenous corticosteroid treatment, or two months after discharge.The ELISA test used was unable to detect TNF-alpha in any of the samples obtained from either patients or controls. CONCLUSION: The results show that 1) there is evidence of systemic inflammation during exacerbation of COPD, and 2) such systemic inflammation does not appear to be influenced significantly by intravenous corticosteroid treatment.

[Recovery of lung function after laparoscopic cholecystectomy: the role of postoperative pain]. / Recuperación de la función pulmonar tras colecistectomía laparoscópica: papel del dolor postoperatorio.

OBJECTIVES: Lung function has been shown to deteriorate after laparoscopic cholecystectomy (LC). The present study evaluated 1) the rate of recovery after LC, and 2) the pathogenic role of postoperative pain in functional deterioration. DESIGN: Lung function was measured 24 hours before LC, upon hospital discharge (48-72 h after LC), and 10 days later. All patients received metamizol after LC until discharge (2 g every 6 h i.v.). Half the patients (analgesia group) received tramadol (150 mg i.m.) 30 minutes before lung function testing on the day of hospital discharge. The remaining patients constituted the control group. PATIENTS: Twenty healthy subjects (53 4 years old) undergoing LC for gall bladder removal. All signed informed consent forms. Measures and outcomes: Patient characteristics and preoperative lung function results were similar in both groups. LC duration and postoperative course were also similar in both groups. All were discharged without complications within 72 hours after LC. Lung function upon discharge (FVC, FEV1, TLC, PaO2 and AaPO2) had deteriorated in both groups (p<0.001). Deterioration was less marked in the analgesia group (p < 0.05). Ten days later, lung function had normalized for all subjects. CONCLUSIONS: These results indicate that after LC, 1) lung function is still abnormal when the patient is discharged from hospital, 2) lung function has fully recovered within 10 days, and 3) postoperative pain contributes significantly to temporary deterioration in lung function.

Outcomes and markers in the assessment of chronic obstructive pulmonary disease.

The clinical presentation of chronic obstructive pulmonary disease (COPD) is highly variable, reflecting the interaction of a complex range of pathological changes including both pulmonary and systemic effects. The consequences of COPD experienced by the patient (i.e. its outcomes) include: symptoms, weight loss, exercise intolerance, exacerbations, health-related quality of life, health resource use and death. No single measure can reflect the variety of pathological effects or adequately describe the nature or severity of COPD. Currently, there are few validated markers for assessing COPD and evaluating the effectiveness of treatment. The forced expiratory volume in one second has been used as a global marker of COPD, but it does not fully reflect the burden of COPD on patients. New markers are needed to better characterise the full clinical spectrum of the disease and to guide the development and assessment of new and more effective therapies. This article considers the distinction between outcomes and markers, the various ways in which markers are used and the need for new markers in the management of chronic obstructive pulmonary disease. The process of marker selection and validation is reviewed and potential new biological, physiological and symptomatic markers for chronic obstructive pulmonary disease are assessed.

Telomere shortening in smokers with and without COPD.

Telomeres are complex DNA-protein structures located at the end of eukaryotic chromosomes. Telomere length shortens with age in all replicating somatic cells. It has been shown that tobacco smoking enhances telomere shortening in circulating lymphocytes. The present study investigated whether this effect was further amplified in smokers who develop chronic obstructive pulmonary disease. Telomere length was determined by fluorescence in situ hybridisation in circulating lymphocytes harvested from 26 never-smokers, 24 smokers with normal lung function and 26 smokers with moderate-to-severe airflow obstruction (forced expiratory flow in one second 48+/-4% predicted). In contrast to never-smokers, telomere length significantly decreased with age in smokers. There was also a dose-effect relationship between the cumulative long-life exposure to tobacco smoking (pack-yrs) and telomere length. The presence and/or severity of chronic airflow obstruction did not modify this relationship. The results of the current study confirm that smoking exposure enhances telomere shortening in circulating lymphocytes. It also demonstrates a dose-effect relationship between exposure to tobacco smoking and telomere length, but failed to show that this effect is amplified in smokers who develop chronic obstructive pulmonary disease.

Antioxidant status in patients with sleep apnoea and impact of continuous positive airway pressure treatment.

The episodes of hypoxia/re-oxygenation associated with the respiratory disturbances observed in patients with obstructive sleep apnoea syndrome (OSAS) may induce the generation of oxygen free radicals. Indeed, several studies suggest that OSAS is associated with oxidative stress. The present study tested the hypothesis that patients with OSAS have an alteration in antioxidant defences. The plasma levels of total antioxidant status (TAS), glutathione peroxidase (GPX), gamma-glutamyltransferase (GGT), vitamins A, E, B12 and folate, and homocysteine were determined in 47 patients with OSAS and 37 healthy subjects. Of these, 27 patients who used continuous positive airway pressure (CPAP) for >4 h.night-1 were re-examined 12 months later. Patients with OSAS had lower TAS (1.4+/-0.16 versus 1.50+/-0.10 mmol.L-1), vitamin A (64+/-19 versus 74+/-17 microg.dL-1) and vitamin E levels (1,525+/-499 versus 1,774+/-503 microg.dL-1), and increased values of GGT (42+/-22 versus 32+/-16 U.L-1) than controls. There was no difference between groups in GPX, homocysteine, vitamin B12 and folate plasma levels. CPAP treatment normalised the levels of TAS (1.50+/-0.13 mmol.L-1) and the activity of GGT (30+/-14 U.L-1) without any influence on vitamins levels. In conclusion, the results indicate that patients with obstructive sleep apnoea syndrome have a decreased antioxidant capacity that is partially reversed by continuous positive airway pressure treatment.

Intracellular cytokine profile of T lymphocytes in patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is characterized by an excessive inflammatory response to inhaled particles, mainly tobacco smoking. T lymphocytes are important regulatory cells that secrete several cytokines and participate actively in this inflammatory response. According to the pattern of cytokines secreted, the immune response is classified as cytotoxic or type 1 [interferon (IFN)-gamma-, interleukin (IL)-2-dependent] and humoral or type 2 (IL-4-, IL-5-, IL-10- and IL-13-dependent). This paper sought to compare the intracellular profile of cytokine expression determined by flow cytometry in T lymphocytes harvested from bronchoalveolar lavage (BAL) and peripheral blood in patients with COPD, smokers with normal lung function and never smokers. We found that BAL T lymphocytes from COPD patients had a higher percentage of positive stained cells for most of the cytokines analysed when compared to never smokers or smokers with normal lung function. Differences reached statistical significance for IL-4, IL-10 and IL-13, particularly in CD8(+) T cells. Furthermore, the expression of most of these cytokines was related inversely to the degree of airflow obstruction present suggesting local activation and/or selective homing of T lymphocytes to the lungs in COPD patients. These observations were not reproduced in circulating T lymphocytes. These results suggest that BAL T lymphocytes in patients with COPD produce more cytokines than in controls and tend to show a type 2 pattern of intracellular cytokine expression, particularly a Tc-2 profile. This is related inversely to the degree of airflow obstruction present.

Phenotypic characterisation of alveolar macrophages and peripheral blood monocytes in COPD.

Alveolar macrophages (AM) participate actively in the inflammatory response that characterises chronic obstructive pulmonary disease (COPD). The present study investigated potential changes in AM phenotypes in patients with COPD. Using flow cytometry, the surface expression of receptors implicated in phagocytosis (CD44, CD36, CD51, CD61, CD14), antigen-presenting capacity (human leukocyte antigen (HLA)-DR), costimulatory molecules (CD80, CD86, CD40) and complement receptor type 3 were assessed in AM from 18 patients with COPD, 14 smokers with normal lung function and nine nonsmokers. When compared to smokers with normal lung function and nonsmokers, the surface expression of HLA-DR and CD80 was lower in AM of patients with COPD. In addition, these patients had a higher percentage of AM with a low level surface expression of CD44. There did not appear to be any difference in the other receptors studied in AM between the three groups. The expression of all these receptors in peripheral blood monocytes also did not differ between groups. In conclusion, these observations suggest that the cell-mediated immune function of alveolar macrophages can be reduced in chronic obstructive pulmonary disease, and that this is a local rather than a systemic event.

Decreased macrophage release of TGF-beta and TIMP-1 in chronic obstructive pulmonary disease.

The present study tested the hypothesis that alveolar macrophages (AM) from patients with chronic obstructive pulmonary disease (COPD) release more pro-inflammatory and/or less anti-inflammatory mediators than those from smokers with normal lung function and never-smokers. AM were sorted by flow cytometry from bronchoalveolar lavage fluid in 13 patients with COPD (mean+/-SEM 67+/-2 yrs, forced expiratory volume in one second (FEV1) 61+/-4% reference), 16 smokers with normal lung function (55+/-2 yrs, FEV1 97+/-4% reference) and seven never-smokers (67+/-7 yrs, FEV1 94+/-4% reference). After sorting, AM were cultured (with and without lipopolysaccharide stimulation) after 4 h and 24 h, and the concentrations of leukotriene B4 (LTB4), transforming growth factor (TGF)-beta1 and tissue inhibitor of metalloproteinase (TIMP)-1 were quantified in the supernatant by ELISA. The production of reactive oxygen intermediates (ROI) in freshly isolated AM was determined by flow cytometry. LTB4 secretion and ROI production were not different between groups. In contrast, AM from COPD patients released significantly less TGF-beta1 and TIMP-1 than those from smokers with normal lung function and nonsmokers. In conclusion, these observations are compatible with reduced anti-inflammatory and anti-elastolytic capacity in chronic obstructive pulmonary disease, which is likely to contribute to the pathogenesis of the disease.