Polymorphisms in PDE4D are Associated with a Risk of COPD in Non-Emphysematous Koreans

Despite extensive effort, only a few chronic obstructive pulmonary disease (COPD)-associated genes have been suggested, indicating that there must be additional risk-associated loci. Here we aimed to identify additional COPD-associated SNPs and to explore the potential relationship between COPD subgroups and the SNPs in the Korean population. We performed a genome-wide association study (GWAS) with 990 Korean individuals; 102 COPD cases and 544 controls for GWAS using Affymetrix SNP array 5.0, and 173 COPD cases and 171 controls for replication. After validating the candidate single nucleotide polymorphisms (SNP), we performed subgroup analysis by disease phenotype. Through GWAS, we identified a novel SNP in the phosphodiesterase-4D (PDE4D) gene [rs16878037 (C>T), p = 1.66 ? 10^?6] that was significantly associated with COPD. This signal in PDE4D was successfully replicated in the independent set (p = 0.041). When we combined the discovery and replication data, the association signal became more significant (p = 5.69 ? 10^?7). In the COPD subgroup analysis, the T allele of rs16878037 was significantly more frequent in COPD patients without severe diffusion capacity impairment (mild mixed and obstruction-dominant group) than in patients with severe impairment (severe mixed and emphysema-dominant groups). This result supports that PDE4D polymorphisms might be involved in the susceptibility to COPD especially in non-emphysematous individuals and that they could also affect the responsiveness of the PDE4 inhibitor treatment.     

Treating COPD with PDE 4 inhibitors

While the pathogenesis of chronic obstructive pulmonary disease (COPD) is incompletely understood, chronic inflammation is a major factor. In fact, the inflammatory response is abnormal, with CD8⁺ T-cells, CD68⁺ macrophages, and neutrophils predominating in the conducting airways, lung parenchyma, and pulmonary vasculature. Elevated levels of the second messenger cAMP can inhibit some inflammatory processes. Theophylline has long been used in treating asthma; it causes bronchodilation by inhibiting cyclic nucleotide phosphodiesterase (PDE), which inactivates cAMP. By inhibiting PDE, theophylline increases cAMP, inhibiting inflammation and relaxing airway smooth muscle. Rather than one PDE, there are now known to be more than 50, with differing activities, substrate preferences, and tissue distributions. Thus, the possibility exists of selectively inhibiting only the enzyme(s) in the tissue(s) of interest. PDE 4 is the primary cAMP-hydrolyzing enzyme in inflammatory and immune cells (macrophages, eosinophils, neutrophils). Inhibiting PDE 4 in these cells leads to increased cAMP levels, down-regulating the inflammatory response. Because PDE 4 is also expressed in airway smooth muscle and, in vitro, PDE 4 inhibitors relax lung smooth muscle, selective PDE 4 inhibitors are being developed for treating COPD. Clinical studies have been conducted with PDE 4 inhibitors; this review concerns those reported to date.     

Efficacy of the novel phosphodiesterase-4 inhibitor BAY 19-8004 on lung function and airway inflammation in asthma and chronic obstructive pulmonary disease (COPD)

Selective inhibitors of phosphodiesterase-4 (PDE4) inhibit the hydrolysis of intracellular cAMP, which may result in bronchodilation and suppression of inflammation. We examined the effect of 1 week treatment with BAY 19-8004 (5 mg once daily), a novel orally administered PDE4 inhibitor, on trough FEV1 and markers of inflammation in induced sputum in patients with asthma or chronic obstructive pulmonary disease (COPD). Seven patients with asthma (mean [SD] FEV1 69.5 [9.3]% predicted; reversibility in FEV1 26.2 [10.1]%; all non-smokers) and 11 patients with COPD (FEV1 58.6 [8.3]% predicted; reversibility in FEV1 6.5 [4.7]%; median [range] 44 [21-90] pack years of smoking) were included in this randomized, double-blind, placebo-controlled trial. FEV1 was measured before and after 1 week of treatment; sputum was induced by 4.5% saline inhalation on the last day of treatment. FEV1 did not improve during either treatment in both patient groups (p>0.2). Sputum cell counts were not different following placebo and BAY 19-8004 treatment in asthma and COPD patients (p>0.2). However, only in patients with COPD, small but significant reductions in sputum levels of albumin and eosinophil cationic protein were observed (p<0.05). In conclusion, 1 week of treatment with the selective PDE4 inhibitor BAY 19-8004 does not affect FEV1 and sputum cell numbers in patients with asthma or COPD. However, such treatment does seem to reduce levels of albumin and eosinophil cationic protein in sputum samples obtained from patients with COPD.     

Roflumilast: clinical benefit in patients suffering from COPD

Background and aims: Chronic obstructive pulmonary disease (COPD) is associated with substantial morbidity and mortality and is characterised by persistent airway inflammation, which leads to impaired airway function, quality of life and intermittent exacerbations. In spite of recent advances in the treatment of COPD, new treatment options for COPD are clearly necessary. The oral phosphodiesterase‐4 (PDE4) inhibitor roflumilast represents a new class of drugs that has shown efficacy and acceptable tolerability in preclinical and short‐term clinical studies in patients with COPD. Methods and results: The available long‐term clinical studies reviewed here suggest that the clinical efficacy of roflumilast is likely because of the suppression of airway inflammation and not through bronchodilation. Furthermore, the clinical studies have shown a modest improvement in airway function, including FEV₁, and a reduction in frequency and severity of COPD exacerbations, as well as a positive effect on several patient‐reported outcomes. The clinical benefit of roflumilast appears to be greatest in patients with more symptomatic and severe disease who experience exacerbations. The most common adverse effects are gastrointestinal events, primarily diarrhoea, nauseas and weight loss. Conclusion: Roflumilast is beneficial for maintenance treatment of patients with severe and symptomatic COPD and with a history of frequent acute exacerbations as an add‐on to treatment with long‐acting bronchodilators. It may have a role as an alternative to inhaled corticosteroids in more symptomatic COPD patients with frequent exacerbations, although direct comparisons are currently lacking. Please cite this paper as: Ulrik CS and Calverley PMA. Roflumilast: clinical benefit in patients suffering from COPD. Clin Respir J 2010; 4: 197–201.     

PDE4 inhibitors in COPD--a more selective approach to treatment

Chronic obstructive pulmonary disease (COPD) is a serious and mounting global public health problem. Although its pathogenesis is incompletely understood, chronic inflammation plays an important part and so new therapies with a novel anti-inflammatory mechanism of action may be of benefit in the treatment of COPD. Cilomilast and roflumilast are potent and selective phosphodiesterase (PDE)4 inhibitors, with an improved therapeutic index compared with the weak, non-selective PDE inhibitor, theophylline. Unlike theophylline, which is limited by poor efficacy and an unfavourable safety and tolerability profile, the selective PDE4 inhibitors are generally well tolerated, with demonstrated efficacy in improving lung function, decreasing the rate of exacerbations and improving quality of life, with proven anti-inflammatory effects in patients with COPD. Theophylline is a difficult drug to use clinically, requiring careful titration and routine plasma monitoring due to the risk of toxic side effects, such as cardiovascular and central nervous system adverse events, with dose adjustments required in many patients, including smokers, the elderly and some patients on concomitant medications. In contrast, the selective PDE4 inhibitors are convenient medications for both patient and physician alike. Hence these agents represent a therapeutic advance in the treatment of COPD, due to their novel mechanism of action and potent anti-inflammatory effects, coupled with a good safety and tolerability profile.     

The preclinical pharmacology of roflumilast – A selective,oral phosphodiesterase 4 inhibitor in development for chronic obstructive pulmonary disease

After more than two decades of research into phosphodiesterase 4 (PDE4) inhibitors, roflumilast (3-cyclopropylmethoxy-4-difluoromethoxy-N-[3,5-di-chloropyrid-4-yl]-benzamide) may become the first agent in this class to be approved for patient treatment worldwide. Within the PDE family of 11 known isoenzymes, roflumilast is selective for PDE4, showing balanced selectivity for subtypes A–D, and is of high subnanomolar potency. The active principle of roflumilast in man is its dichloropyridyl N-oxide metabolite, which has similar potency as a PDE4 inhibitor as the parent compound. The long half-life and high potency of this metabolite allows for once-daily, oral administration of a single, 500-μg tablet of roflumilast.The molecular mode of action of roflumilast – PDE4 inhibition and subsequent enhancement of cAMP levels – is well established. To further understand its functional mode of action in chronic obstructive pulmonary disease (COPD), for which roflumilast is being developed, a series of in vitro and in vivo preclinical studies has been performed.COPD is a progressive, devastating condition of the lung associated with an abnormal inflammatory response to noxious particles and gases, particularly tobacco smoke. In addition, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), significant extrapulmonary effects, including comorbidities, may add to the severity of the disease in individual patients, and which may be addressed preferentially by orally administered remedies. COPD shows an increasing prevalence and mortality, and its treatment remains a high, unmet medical need.In vivo, roflumilast mitigates key COPD-related disease mechanisms such as tobacco smoke-induced lung inflammation, mucociliary malfunction, lung fibrotic and emphysematous remodelling, oxidative stress, pulmonary vascular remodelling and pulmonary hypertension. In vitro, roflumilast N-oxide has been demonstrated to affect the functions of many cell types, including neutrophils, monocytes/macrophages, CD4+ and CD8+ T-cells, endothelial cells, epithelial cells, smooth muscle cells and fibroblasts. These cellular effects are thought to be responsible for the beneficial effects of roflumilast on the disease mechanisms of COPD, which translate into reduced exacerbations and improved lung function. As a multicomponent disease, COPD requires a broad therapeutic approach that might be achieved by PDE4 inhibition. However, as a PDE4 inhibitor, roflumilast is not a direct bronchodilator.In summary, roflumilast may be the first-in-class PDE4 inhibitor for COPD therapy. In addition to being a non-steroid, anti-inflammatory drug designed to target pulmonary inflammation, the preclinical pharmacology described in this review points to a broad functional mode of action of roflumilast that putatively addresses additional COPD mechanisms. This enables roflumilast to offer effective, oral maintenance treatment for COPD, with an acceptable tolerability profile and the potential to favourably affect the extrapulmonary effects of the disease.     

The novel phosphodiesterase 4 inhibitor, CI-1044, inhibits LPS-induced TNF-alpha production in whole blood from COPD patients

Chronic obstructive pulmonary disease (COPD) is a common, progressive respiratory disease that causes great morbidity and mortality despite treatment. Tumor necrosis factor alpha (TNF-alpha) plays a central role as a pro-inflammatory cytokine in COPD. TNF-alpha release is markedly inhibited by phosphodiesterase type 4 (PDE4) inhibitors that have proven efficacious in COPD clinical trials. The aim of this study was to compare the in vitro activities of the novel selective PDE4 inhibitors CI-1044 compared to well-known PDE4 inhibitors, rolipram and cilomilast, and to the glucocorticoid dexamethasone at reducing lipopolysaccharide (LPS)-induced TNF-alpha release in whole blood from COPD patients and healthy subjects. In the whole blood from COPD patients pre-incubation with PDE4 inhibitors or dexamethasone resulted in a dose-dependent inhibition of LPS-induced TNF-alpha release with IC(50) values of 1.3+/-0.7, 2.8+/-0.9 microM, higher to 10 microM and lesser than 0.03 microM for CI-1044, rolipram, cilomilast and dexamethasone, respectively. We observed a similar inhibition in the whole blood from healthy volunteers with, however, higher IC(50) values. These results indicate that CI-1044 inhibits in vitro LPS-induced TNF-alpha release in whole blood from COPD patients better than rolipram and cilomilast and suggested that it could be a useful anti-inflammatory therapy in COPD.     

Effect of 1-year treatment with roflumilast in severe chronic obstructive pulmonary disease

RATIONALE: The oral phosphodiesterase-4 (PDE4) inhibitor, roflumilast, can improve lung function in moderate chronic obstructive pulmonary disease (COPD). Whether treatment is effective in more severe COPD (GOLD [Global Initiative for Chronic Obstructive Lung Disease] stages III and IV) over a longer period is unknown. OBJECTIVES: To determine whether roflumilast improves lung function and decreases exacerbation frequency over 1 year in patients with stable COPD. METHODS: We conducted a randomized, placebo-controlled, double-blind, parallel-group trial for 1 year. We recruited 1,513 patients (mean post-bronchodilator FEV1 41% predicted), 760 receiving oral 500 microg roflumilast and 753 receiving placebo once daily. MEASUREMENTS AND MAIN RESULTS: We recorded post-bronchodilator FEV1, exacerbation rate, St. George's Respiratory Questionnaire total score at the study end point, and number and type of reported adverse events during treatment. Post-bronchodilator FEV1 increased by 39 ml with roflumilast compared with placebo by 52 weeks (p=0.001). The mean exacerbation rate was low and comparable in both treatment groups (0.86 vs. 0.92 exacerbations/patient/yr for roflumilast and placebo, respectively). In a retrospective analysis, the exacerbation rate in patients in GOLD stage IV disease was 36% lower in patients treated with roflumilast than in those treated with placebo (1.01 vs. 1.59 exacerbations/patient/year, respectively; p=0.024). The St. George's Respiratory Questionnaire total score did not differ between treatments. The commonest adverse events related to roflumilast treatment were diarrhea, nausea, and headache, which usually subsided during continued treatment. However, roflumilast resulted in more withdrawals within the first 3 to 4 weeks of administration. CONCLUSIONS: In severe, stable COPD, PDE4 inhibition with roflumilast produced a modest but significant improvement in lung function without changing the exacerbation rate or health status. However, patients with very severe disease experienced fewer exacerbations with roflumilast.     

Selective phosphodiesterase-4 inhibitors in chronic obstructive lung disease

PURPOSE OF REVIEW: Chronic obstructive pulmonary disease (COPD) is a disease state characterized by airflow limitation that is usually progressive. In addition, an abnormal inflammatory response of the lungs to noxious particles or gases can be seen throughout the airways, parenchyma, and pulmonary vasculature. So far, anti-inflammatory medications (eg, inhaled corticosteroids) have failed to show a major effect on the decline of lung function in COPD patients. Novel anti-inflammatory therapies such as selective phosphodiesterase 4 (PDE4) inhibitors are in clinical development. Their potential role in the management of COPD is described in this review. RECENT FINDINGS: Some of the selective PDE4 inhibitors have demonstrated in vitro and in vivo anti-inflammatory activity on cells commonly linked to airway inflammation in COPD, such as neutrophils. While these agents seem to offer only a modest improvement in lung function compared with other bronchodilators, their anti-inflammatory effects appear to provide some substantial benefits in reducing exacerbations and improving health-related quality of life. SUMMARY: Based on the available data, the second generation of selective PDE4 inhibitors will likely provide additional therapeutic options for the management of COPD. These agents may become an important tool in the treatment of this disease, since they target three important components of COPD: airway obstruction, inflammation, and structural changes.     

The effects of cigarette smoke on airway inflammation in asthma and COPD: therapeutic implications

Asthma and COPD are two chronic inflammatory disorders of the airway characterized by airflow limitation. While many similarities exist between these two diseases, they are pathologically distinct due to the involvement of different inflammatory cells; predominantly neutrophils, CD8 lymphocytes in COPD and eosinophils and CD4 lymphocytes in asthma. Cigarette smoking is associated with accelerated decline of lung function, increased mortality, and worsening of symptoms in both asthma and COPD. Furthermore, exposure to cigarette smoke can alter the inflammatory mechanisms in asthma to become similar to that seen in COPD with increasing CD8 cells and neutrophils and may therefore alter the response to therapy. Cigarette smoke exposure has been associated with a poor response to inhaled corticosteroids which are recommended as first line anti-inflammatory medications in asthma and as an add-on therapy in patients with severe COPD with history of exacerbations. While the main proposed mechanism for this altered response is the reduction of the histone deacetylase 2 (HDAC2) enzyme system, other possible mechanisms include the overexpression of GR-β, activation of p38 MAPK pathway and increased production of inflammatory cytokines such as IL-2, 4, 8, TNF-α and NF-K?. Few clinical trials suggest that leukotriene modifiers may be an alternative to corticosteroids in smokers with asthma but there are currently no drugs which effectively reduce the progression of inflammation in smokers with COPD. However, several HDAC2 enhancers including low dose theophylline and other potential anti-inflammatory therapies including PDE4 inhibitors and p38 MAPK inhibitors are being evaluated.     

磷酸二酯酶抑制剂与呼吸道疾病

磷酸二酯酶(PDE)存在于许多炎症细胞及结构细胞中,目前已发现11种.PDE抑制剂主要抑制体内环磷酸腺苷(cAMP)及环磷酸鸟苷(cGMP)水解,使细胞内cAMP及cGMP浓度增加,引起一系列生理功能,如平滑肌舒张、减轻细胞炎症及免疫反应等.PDE4特异性水解cAMP,选择性PDE4抑制剂具有广泛抗炎作用,如抑制细胞趋化,抑制中性粒细胞、嗜酸粒细胞、巨噬细胞及T细胞细胞因子及化学趋化物质释放.第二代PDE4抑制剂Cilomilast和Roflumilast已进入临床实验阶段,并已证实对支气管哮喘(简称哮喘)及慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)有效.由于胃肠道副作用,这类药物临床应用受到一定限制.PDE5可特异性水解cGMP,对缺氧性肺动脉高压和血管重塑有效.PDE3和PDE7特异性水解cAMP,PDE7参与T细胞激活.目前其他PDE抑制剂与PDE4抑制剂混合制剂正在研发中.PDE4-PDE7双重抑制剂可能对哮喘及COPD更有效.PDE3-PDE4双重抑制剂具有更强的支气管舒张作用及气道保护作用.     

Phosphodiesterase-4 inhibitors for asthma and chronic obstructive pulmonary disease

Inhibitors of phosphodiesterase type 4 (PDE4) act by increasing intracellular concentrations of cyclic AMP, which has a broad range of anti-inflammatory effects on various key effector cells involved in asthma and chronic obstructive pulmonary disease (COPD). The therapeutic ratio for PDE4 inhibitors is thought to be determined by selectivity on receptor subtypes for relative effects on PDE4B (anti-inflammatory) and PDE4D (emesis). The two main orally active PDE4 inhibitors in the late phase III of clinical development are cilomilast and roflumilast; the latter (and its active metabolite N-oxide) is more selective and potent with a superior therapeutic ratio. Studies on cilomilast in COPD based on bronchial biopsy material have shown a broad range of anti-inflammatory activity, and the available evidence on clinical outcomes for up to 6 months with cilomilast 15 mg twice daily and roflumilast 500 mug once daily have shown variable but significant effects on exacerbations and quality of life, with small improvements in measures of pulmonary function. Roflumilast has a better safety and tolerability profile than cilomilast, with the main adverse effects being nausea, diarrhoea, and abdominal pain. Roflumilast also has activity in asthma as assessed by its attenuation of allergen and exercise challenges, and it shows clinical efficacy equivalent to that of beclomethasone dipropionate 400 mug daily. The emerging results of clinical trials on PDE4 inhibitors in asthma and COPD should be interpreted with cautious optimism since much of the evidence has been published only in abstract form to date. The next few years should resolve important issues about the potential role of these drugs as oral non-steroidal anti-inflammatory therapy for asthma and COPD and their place in management guidelines. Ultimately, clinicians will want to know whether PDE4 inhibitors are anything more than expensive "designer" theophylline, the archetypal non-selective phosphodiesterase inhibitor.     

Severe COPD Alters Muscle Fiber Conduction Velocity During Knee Extensors Fatiguing Contraction

The aim of this study was to assess the changes in muscle fiber conduction velocity (CV), as a sign of fatigue during knee extensor contraction in patients with chronic obstructive pulmonary disease (COPD) as compared with healthy controls. Eleven male patients (5 with severe and 6 with moderate COPD; age 67 ± 5 years) and 11 age-matched healthy male controls (age 65 ± 4 years) volunteered for the study. CV was obtained by multichannel surface electromyography (EMG) from the vastus lateralis (VL) and medialis (VM) of the quadriceps muscle during isometric, 30-second duration knee extension at 70% of maximal voluntary contraction. The decline in CV in both the VL and VM was steeper in the severe COPD patients than in healthy controls (for VL: severe COPD vs. controls ?0.45 ± 0.07%/s; p < 0.001, and for VM: severe COPD vs. controls ?0.54 ± 0.09%/s, p < 0.001). No difference in CV decline was found between the moderate COPD patients and the healthy controls. These findings suggest that severe COPD may impair muscle functions, leading to greater muscular fatigue, as expressed by CV changes. The results may be due to a greater involvement of anaerobic metabolism and a shift towards fatigable type II fibers in the muscle composition of the severe COPD patients.     

Phosphodiesterase 4-selective inhibition: novel therapy for the inflammation of COPD

Chronic obstructive pulmonary disease (COPD), which is increasing in prevalence and a leading cause of death worldwide, is characterised by an 'abnormal' inflammatory response. There is a predominance of CD8(+) T cells, CD68(+) macrophages and, in exacerbations-neutrophils, in both conducting airways and lung parenchyma. Smoking is the most common etiological factor leading to COPD and smoking cessation is the most effective approach to the management of COPD, but it does not resolve the underlying inflammation of COPD, which persists, even in ex-smokers. The presence of mucosal inflammation serves as the rationale for anti-inflammatory therapy. However, while there are reductions in the numbers of mast cells following treatment with inhaled steroids, CD8(+), CD68(+) cells and neutrophils are refractory to such treatment, highlighting a need for additional, more targeted interventions. Phosphodiesterase 4 (PDE4) inhibitors are a promising and novel drug class that have potent activity against several key components of the inflammatory process in COPD. A recently published study has shown that the selective PDE4 inhibitor, cilomilast, reduces the numbers of bronchial mucosal CD8(+) and CD68(+) cells and neutrophils. This review focuses on the nature of the inflammation in COPD and considers how selective PDE4 inhibitors may optimize and advance our treatment of this chronic condition.     

Invariant natural killer T cells in chronic obstructive pulmonary disease

Background and objective: Invariant natural killer T (iNKT) cells may play an important role in regulating the innate and acquired immune systems in chronic obstructive pulmonary disease (COPD). However, there is little information regarding the potential role of iNKT cells in the pathogenesis of COPD. To investigate whether iNKT cells have an important role in COPD, the frequency of iNKT cells in peripheral blood of patients with COPD was analysed. Methods: This was a comparative study of 28 patients with COPD and 19 age‐matched healthy control subjects. Blood iNKT cells were stained with 6B11 mAb, anti‐T cell receptor Vα24 mAb, anti‐T cell receptor Vβ11 mAb or α‐galactosylceramide‐loaded CD1d‐tetramer, and analysed by flow cytometry. Results: The frequency of CD4⁺ 6B11⁺ iNKT, CD4⁺ Vα24⁺ iNKT, CD4⁺ Vβ11⁺ iNKT and CD3⁺ 6B11⁺ iNKT cells was significantly lower in peripheral blood of patients with COPD than in that of healthy control subjects. The frequency of CD4⁺ 6B11⁺ iNKT cells was significantly lower in patients with exacerbations of COPD compared with those with stable COPD. Conclusions: The frequency of iNKT was decreased in peripheral blood of patients with COPD. These results strongly suggest that iNKT cells may play an important role in the pathogenesis of COPD.     

磷酸二酯酶4D基因单核苷酸多态性与COPD相关性研究

目的 探讨磷酸二酯酶4D (PDE4D)基因单核苷酸多态性(SNP)与COPD相关性.方法 选取8个SNP位点SNP1=rs11740402,SNP2=rs17528473,SNP3=rs17780213,SNP4=rs1529843,SNP5=rs11743928,SNP6=rs26956,SNP7=rs35387,SNP8=rs35386,以北京某社区40～80岁人群为研究对象,共入选136例受试者,COPD组71例和对照组65例,均为汉族.设计目标SNP位点上下游引物,PCR扩增目标片段,Sanger测序法检测目标片段碱基,x2检验比较2组在等位基因和基因型分布频率上的差异,非条件Logistic回归评价SNP位点与COPD之间的相关性.结果 8个SNP位点其基因型分布在COPD组和对照组均符合Hardy-Weinberg平衡,在对照组受试者连锁不平衡(Linkage Disequilibrium,LD)分析时发现SNP1、SNP2处于连锁不平衡,形成LDBlock1,SNP6、SNP7和SNP8处于连锁不平衡,形成LD Block2,SNP5基因型均为A/A型,不能与其他SNP位点形成LD Block.单倍体型分析发现在COPD组和对照组中差异无统计学意义(P＞0.05).基于等位基因的关联分析中发现2组病例之间差异无统计学意义(P＞0.05),在基因型的关联分析中发现位点SNP8基因型频率在COPD组和对照组差异有统计学意义(P＜0.05),在进一步非条件Logistic回归分析中发现SNP8在Ressessive遗传模型时与COPD存在相关性,G/G基因型在COPD组和对照组分别为20.3％和6.3％(P＜0.05,OR =4.07,95％ CI为1.26～13.18),提示SNP8的G/G基因型与COPD易感性增加有关.结论 研究结果提示PDE4D基因SNP可能与COPD的发生发展相关,SNP8的G/G基因型可能是COPD易感性的一个预测因子.     

Pulmonary rehabilitation improves exercise capacity and quality of life in underweight patients with chronic obstructive pulmonary disease

Background and objective: An estimated 20–40% of COPD patients are underweight. We sought to confirm the physiological and psychosocial benefits of pulmonary rehabilitation programmes (PRP) in underweight compared with non‐underweight patients with COPD. Methods: Twenty‐two underweight COPD patients with BMI <20 kg/m², and 22 non‐underweight COPD patients, who were matched for FEV₁ and age, were studied. All patients had moderate‐to‐very severe COPD. All patients participated in 12‐week, hospital‐based outpatient PRP consisting of two sessions per week. Baseline and post‐PRP status were evaluated by spirometry, cardiopulmonary exercise testing, ventilatory muscle strength and the St. George's Respiratory Questionnaire (SGRQ). Results: At baseline, the age distribution and airflow obstruction were similar in underweight and non‐underweight patients with COPD. Baseline exercise capacity, inspiratory muscle strength and SGRQ total and symptoms scores were significantly lower in the underweight patients (all P < 0.05). After the PRP, there was significant weight gain in the underweight COPD patients (mean increase 0.8 kg, P = 0.01). There were also significant improvements in peak oxygen uptake, peak workload and the SGRQ total, symptoms, activity and impact scores in both underweight and non‐underweight patients with COPD (all P < 0.05). Conclusions: Underweight patients with COPD have impaired exercise capacity and health‐related quality of life (HRQL). Exercise training with supplemental oxygen may result in significant weight gains and improvements in exercise capacity and HRQL. Exercise training is indicated for underweight patients with COPD.     

Severity and outcomes of hospitalised community-acquired pneumonia in COPD patients

Chronic obstructive pulmonary disease (COPD) is a frequent comorbidity in patients with community-acquired pneumonia (CAP). We investigated the impact of COPD on outcomes of CAP patients. We prospectively studied the clinical presentation of 1,379 patients admitted with CAP during a 4-yr period. A comparative analysis of disease severity and course was performed between 212 patients with COPD, as confirmed by spirometry, and 1,167 non-COPD patients. COPD patients (mean forced expiratory volume in 1 s 47.7 ± 16.3% predicted) were older and more likely to have previously received antibiotics (37.1% versus 28.3%; p<0.01) than those without COPD. They presented with more severe respiratory failure (arterial oxygen tension/inspiratory oxygen fraction 270.4 versus 287.8; p<0.01) and more severe pneumonia (pneumonia severity index 118.3 versus 108.5; p<0.001) compared with non-COPD patients. However, COPD patients had less multilobar infiltration (44 (21%) versus 349 (30%); p<0.01) and fewer pulmonary complications (24 (14%) versus 241 (24%); p<0.01). A total of 89 (6.5%) patients died within 30 days. COPD patients had no significant difference in their 30-day mortality rate compared with non-COPD patients (nine (4.2%) patients versus 81 (7%); p = 0.14). Despite worse clinical presentation, COPD patients had a similar mortality rate compared to non-COPD patients. Previous antibiotic treatment and the decreased incidence of pulmonary complications in COPD may account for these findings.