The Association between Dyslipidemia and Pulmonary Diseases

Dyslipidemia is one of the most common diseases worldwide. As a component of metabolic syndrome, the prevalence and mechanism by which dyslipidemia promotes cardiovascular diseases has been well studied, although the relationship between pulmonary diseases is not well understood. Because the lung is a respiratory organ with a large surface area and is exposed to the environment outside the body, it continuously inhales various substances. As a result, pulmonary diseases have a vast diversity, including chronic inflammatory diseases, allergic diseases, cancers, and infectious diseases. Recently, growing evidence has suggested that dyslipidemia plays a role in the pathogenesis and prognosis of various pulmonary diseases. We herein review the current understanding of the relationship between dyslipidemia and pulmonary diseases, including chronic obstructive pulmonary diseases, asthma, and lung cancer, and infectious pulmonary diseases, including community-acquired pneumonia, tuberculosis, nontuberculous mycobacterial pulmonary disease, and COVID-19. In addition, we focus on recent evidence of the utility of statins, specifically 3-hydroxy-3-methylglutaryl-coA reductase inhibitors, in the prevention and treatment of the various pulmonary diseases described above.

Serum levels of HMW adiponectin and its receptors are associated with cytokine levels and clinical characteristics in chronic obstructive pulmonary disease

We aimed to investigate the changes in the levels of high-molecular-weight (HMW) adiponectin, adiponectin receptors, and cytokines in patients with chronic obstructive pulmonary disease (COPD), as well as their potential relationships. Forty-one patients who underwent lobectomy for lung lesions and had a clear postoperative pathological diagnosis were divided into the non-COPD (N = 23) and COPD (N = 18) groups. HMW adiponectin, cytokine, and T-cadherin levels in serum and tissues were detected by enzyme-linked immunosorbent assay. The levels of HMW adiponectin and cytokine (interleukin [IL]-6, IL-10, surfactant protein D, 4-hydroxynonenal, tumor necrosis factor-α, and C reactive protein) in the serum and tissues increased in the COPD group compared to those in the non-COPD group. Patients with COPD exhibited AdipoR1 upregulation and AdipoR2 downregulation. Although T-cadherin did not differ significantly between patients with and those without COPD, its expression was elevated during the progression from COPD with benign lung lesions to combined lung cancer. Furthermore, the HMW adiponectin levels were significantly correlated with the cytokine levels and the clinical characteristics of COPD. HMW adiponectin and its receptors affect the inflammatory process in COPD and may further contribute to the progression of the disease to malignancy.

Adiponectin Increase in Patients Affected by Chronic Obstructive Pulmonary Disease with Overlap of Bronchiectasis

Chronic obstructive pulmonary disease (COPD) is characterized by respiratory symptoms and non-reversible airflow limitation with recurrent episodes of acute exacerbations. The concurrent presence of bronchiectasis in patients with COPD is associated with reduced respiratory function as well as increased exacerbation risk. Adiponectin is a promising biomarker in COPD, as greater high molecular weight (HMW) oligomer levels have been observed among COPD patients. Here, we investigate adiponectin levels in two groups of COPD patients characterized by the presence or absence of bronchiectasis (BCO), comparing both groups to healthy controls. We evaluated serum adiponectin levels in COPD patients, those with BCO, and healthy subjects and characterized the pattern of circulating adiponectin oligomers. We found that forced volume capacity % (FVC%) and forced expiratory volume % (FEV1%) were lower for BCO patients than for COPD patients. COPD patients had higher levels of adiponectin and its HMW oligomers than healthy controls. Interestingly, BCO patients had higher levels of adiponectin than COPD patients. We showed that expression levels of IL-2, -4, and -8, IFN-γ, and GM-CSF were significantly higher in BCO patients than in healthy controls. Conversely, IL-10 expression levels were lower in BCO patients. Our data suggest that the increased levels of adiponectin detected in the cohort of BCO patients compared to those in COPD patients without bronchiectasis might be determined by their worse airway inflammatory state. This hypothesis suggests that adiponectin could be considered as a biomarker to recognize advanced COPD patients with bronchiectasis.

Relationship among Body Composition, Adipocytokines, and Irisin on Exercise Capacity and Quality of Life in COPD: A Pilot Study

Adipose tissue is an endocrine organ that interferes with the severity of chronic obstructive pulmonary disease (COPD). Although inflammatory markers, body composition, and nutritional status have a significant impact on pulmonary function, the real contribution of adipocytokines and myokines in COPD is still controversial. We aimed to evaluate the role played by the body composition, leptin, adiponectin, haptoglobin, and irisin on the functional exercise capacity, respiratory function, and quality of life (QoL) in COPD. In 25 COPD (20% GOLD-1; 60% GOLD-2; 20% GOLD-3) patients and 26 matched control subjects, we find that leptin, total adiponectin and haptoglobin are significantly increased whereas the 6 min walk test (6MWT) and physical functioning scores are significantly decreased in COPD versus controls. A significant positive relationship is found between leptin and fat mass and between 6MWT and the good health indicators of nutritional status. A significant inverse relationship is found between 6MWT and leptin and fat mass, FEV₁ and haptoglobin, and irisin and haptoglobin. Phase angle and leptin level are significant predictors for functional exercise capacity assessed with 6MWT. Taken altogether, the results of this pilot study further support the role played by body composition and adipocytokines on exercise capacity respiratory function and QoL in COPD.

Adiponectin: friend or foe in obesity and inflammation

Adiponectin is an adipokine predominantly produced by fat cells, circulates and exerts insulin-sensitizing, cardioprotective and anti-inflammatory effects. Dysregulation of adiponectin and/or adiponectin signaling is implicated in a number of metabolic diseases such as obesity, insulin resistance, diabetes, and cardiovascular diseases. However, while the insulin-sensitizing and cardioprotective effects of adiponectin have been widely appreciated in the field, the obesogenic and anti-inflammatory effects of adiponectin are still of much debate. Understanding the physiological function of adiponectin is critical for adiponectin-based therapeutics for the treatment of metabolic diseases.

Mechanisms Linking COPD to Type 1 and 2 Diabetes Mellitus: Is There a Relationship between Diabetes and COPD?

Chronic obstructive pulmonary disease (COPD) patients frequently suffer from multiple comorbidities, resulting in poor outcomes for these patients. Diabetes is observed at a higher frequency in COPD patients than in the general population. Both type 1 and 2 diabetes mellitus are associated with pulmonary complications, and similar therapeutic strategies are proposed to treat these conditions. Epidemiological studies and disease models have increased our knowledge of these clinical associations. Several recent genome-wide association studies have identified positive genetic correlations between lung function and obesity, possibly due to alterations in genes linked to cell proliferation; embryo, skeletal, and tissue development; and regulation of gene expression. These studies suggest that genetic predisposition, in addition to weight gain, can influence lung function. Cigarette smoke exposure can also influence the differential methylation of CpG sites in genes linked to diabetes and COPD, and smoke-related single nucleotide polymorphisms are associated with resting heart rate and coronary artery disease. Despite the vast literature on clinical disease association, little direct mechanistic evidence is currently available demonstrating that either disease influences the progression of the other, but common pharmacological approaches could slow the progression of these diseases. Here, we review the clinical and scientific literature to discuss whether mechanisms beyond preexisting conditions, lifestyle, and weight gain contribute to the development of COPD associated with diabetes. Specifically, we outline environmental and genetic confounders linked with these diseases.

Possible association of high-density lipoprotein cholesterol levels with trunk muscle deficits and decrease in energy expenditure in patients with or at risk for COPD: A pilot study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with low muscle mass and function caused by malnutrition and physical inactivity. We aimed to investigate possible associations between serum biomarkers and clinical traits including computed tomography-derived muscle measurements and energy expenditure indices in COPD.

METHODS

Total energy expenditure (TEE) was measured by the doubly labeled water method, while physical activity level (PAL) was calculated as TEE/basal metabolic rate. Cross-sections and densities of pectoralis, rectus abdominis, and erector spinae muscles were measured. Serum biomarkers included adiponectin, insulin-like growth factor-1, and high-density lipoprotein (HDL)- and low-density lipoprotein (LDL)-cholesterol (C).

RESULTS

HDL-C levels were significantly correlated with all muscle areas, densities, and TEE. Only LDL-C levels were correlated with PAL.

CONCLUSIONS

HDL-C level was a potential biomarker for trunk muscle volumes and functions, as well as total energy expenditure in COPD.

Association of BMI and Change in Weight With Mortality in Patients With Fibrotic Interstitial Lung Disease

BACKGROUND

Mortality risk assessment in interstitial lung disease (ILD) is challenging. Our objective was to determine the prognostic significance of BMI and change in weight in the most common fibrotic ILD subtypes.

RESEARCH QUESTION

Could BMI and weight loss over time be reliable prognostic indicators in patients with fibrotic ILD?

STUDY DESIGN AND METHODS

This observational retrospective multicenter cohort study enrolled patients with fibrotic ILD from the six-center CAnadian REgistry for Pulmonary Fibrosis (CARE-PF, derivation) and the ILD registry at the University of California, San Francisco (UCSF, validation). Patients were subcategorized as underweight (BMI < 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), or obese (BMI > 30). Annual change in weight was calculated for all years of follow-up as the slope of best fit using the least square method based on every available measurement. Separate multivariable analyses evaluated the associations of BMI and change in weight with mortality, adjusting for common prognostic variables.

RESULTS

The derivation and validation cohorts included 1,786 and 1,779 patients, respectively. Compared with patients with normal BMI, mortality was highest in patients who were underweight (hazard ratio [HR], 3.19; 95% CI, 1.88-5.43; P < .001) and was lowest in those who were overweight (HR, 0.52; 95% CI, 0.36-0.75; P < .001) or obese (HR, 0.55; 95%CI, 0.37-0.83; P < .001) in the analysis adjusted for the ILD-GAP (gender, age, physiology) Index. Patients who had a weight loss of at least 2 kg within 1 year had increased risk of death in the subsequent year (HR, 1.41; 95% CI, 1.01-1.97; P = .04) after adjustment for the ILD-GAP Index and baseline BMI category, with a plateau in risk for patients with greater weight loss. Consistent results were observed in the validation cohort.

INTERPRETATION

Both BMI and weight loss are independently associated with 1-year mortality in fibrotic ILD. BMI and weight loss may be clinically useful prognostic indicators in fibrotic ILD.

Adiponectin and cardiometabolic trait and mortality: where do we go?

Adiponectin is an adipocyte-derived cytokine known for its cardioprotective effects in preclinical studies. Early epidemiologic studies replicated these findings and drew great interest. Subsequent large-scale prospective cohorts, however, showed that adiponectin levels seemed not to relate to incident coronary artery disease (CAD). Even more surprisingly, a paradoxical increase of all-cause and cardiovascular (CV) mortality with increased adiponectin levels was reported. The adiponectin-mortality paradox has been explained by some groups asserting that adiponectin secretion is promoted by elevated natriuretic peptides (NP). Other groups have proposed that adiponectin is elevated due to adiponectin resistance in subjects with metabolic syndrome or heart failure (HF). However, there is no unifying theory that can clearly explain this paradox. In patients with HF with reduced ejection fraction (HFrEF), stretched cardiomyocytes secrete NPs, which further promote release of adiponectin from adipose tissue, leading to adiponectin resistance. On the other hand, adiponectin biology may differ in patients with heart failure with preserved ejection fraction (HFpEF), which constitutes 50% of all of HF. Most HFpEF patients are obese, which exerts inflammation and myocardial stiffness, that is likely to prevent myocardial stretch and subsequent NP release. This segment of the patient population may display a different adiponectin biology from its HFrEF counterpart. Dissecting the adiponectin-mortality relation in terms of different HF subtypes may help to comprehensively understand this paradox. Mendelian Randomization (MR) analyses claimed that adiponectin levels are not causally related to CAD or metabolic syndrome. Results from MR studies, however, should be interpreted with great caution because the underlying history of CAD or CHF were not taken into account in these analyses, an issue that may substantially confound the results. Here, we discuss many aspects of adiponectin; cardiometabolic traits, therapeutic interventions, and the ongoing debate about the adiponectin paradox, which were recently described in basic, epidemiologic, and clinical studies.

Comorbidity burden may explain adiponectin's paradox as a marker of increased mortality risk in hemodialysis patients

Despite experimental evidence of beneficial metabolic, antiatherosclerotic and antiinflammatory effects of the 30 kDa adipokine, adiponectin, maintenance hemodialysis (MHD) patients with high adiponectin blood levels have paradoxically high mortality rates. We aimed to examine the direction of the associations between adiponectin and all-cause and cardiovascular mortality as well as with markers of oxidative stress, inflammation and nutrition in MHD patients with varying degrees of comorbidities. A cohort of 261 MHD patients (mean age 68.6 ± 13.6 years, 38.7% women), grouped according to baseline comorbidity index (CI) and serum adiponectin levels, were followed prospectively for six years. High and low concentrations were established according to median CI and adiponectin levels and cross-classified. Across the four CI-adiponectin categories, the group with low comorbidities and high adiponectin exhibited the best outcomes. Conversely, the high comorbidity group with high adiponectin levels had the lowest survival rate in both all-cause mortality (log rankχ² = 23.74, p < 0.001) and cardiovascular mortality (log rankχ² = 34.16, p < 0.001). Further data adjustment for case-mix covariates including fat mass index did not substantially affect these results. In conclusion, the direction of adiponectin’s prognostic associations in MHD patients is inverse in those with few comorbidities and direct in those with many comorbidities.

Metabolic Syndrome and Abnormal Peri-Organ or Intra-Organ Fat (APIFat) Deposition in Chronic Obstructive Pulmonary Disease: An Overview

Chronic obstructive pulmonary disease (COPD) is a common disorder with an increasing prevalence, characterised by persistent respiratory symptoms and airflow limitation. Systemic inflammation is involved in the pathogenesis of COPD and can also predispose to metabolic disorders (e.g., metabolic syndrome (MetS) and non-alcoholic fatty liver disease (NAFLD)). Such comorbidities can negatively affect COPD outcomes, cardiovascular risk, and quality of life. Apart from NAFLD, abnormal peri-organ or intra-organ fat (APIFat) could be considered as markers for cardiometabolic diseases and even for COPD. The present narrative review considers the associations of COPD with MetS, NAFLD, and other APIFat, including epicardial, perirenal, peripancreatic, and intramuscular adipose tissue. Further research is needed to define these relationships and identify any potential clinical implications.

Contentious role of 'Good Adiponectin' in pulmonary and cardiovascular diseases: Is adiponectin directed therapy a boon or a bane?

After two decades of its discovery, numerous facts of adiponectin (APN) biology has been uncovered, yet, APN remains an elusive adipokine. Findings from clinical studies and animal models established APN's ameliorative role in cardiovascular disease (CVD) and pulmonary disease (PD) but the same condition is prognostic for mortality in the same set of patients which cornered APN towards a dubious state. A repertoire of mechanisms associated with the positive association of APN in both lean/cachectic or obese CVD and PD patients from past publications are evaluated. Newer pharmacological agent may be explored to regulate elevated blood APN concentration in COPD or CHF patients whereas administration of recombinant APN as well as growth hormone may augment blood APN concentration in obese subjects associated with low blood and intracellular APN concentration. However, some APN directed therapy in clinical as well as in pre-clinical setup has pronounced some contentious effects. After reviewing the mechanisms of the contentious role of APN functioning in pathologic conditions of CVD and PD in both lean and obese conditions, the authors came to conclusion that APN directed therapy may be utilized with caution keeping in mind the different age group, sex and the different CVD as well as pulmonary diseases they are suffering from.

Low FEV1 Is Associated With Increased Risk Of Cachexia In COPD Patients

Background

Chronic obstructive pulmonary disease (COPD) has been introduced as a major public health problem. It has been suggested that disruption in function or some adipokines and serum proteins' signaling could play crucial roles in lung diseases. This study's purpose was to investigate the association between serum levels of S100A1, ZAG, and adiponectin with FEV1 in COPD patients.

Methods

In this cross-sectional study, 90 clinically stable outpatient males with age ranging from 40 to 70 years with COPD diagnosis - FEV1/FVC < 70% - were divided into two groups: mild-moderate COPD patients; FEV1 ≥ 50 (n=52) VS severe and very severe COPD patients; FEV1 < 50 (n=38). The serum levels of ZAG, S100A1, and adiponectin were measured by the use of enzyme-linked immunosorbent assay.

Results

In the present study, lower FEV1 was significantly associated with increased risk of cachexia (OR = 5.76, 95% CI: 2.28-14.54). The serum level of ZAG was significantly higher in the mild-moderate COPD patients in comparison with the severe-very severe COPD patients (p<0.035). However, the resting metabolic rate (RMR) level was significantly higher in FEV1<50 group compared to FEV1≥50 group (p<0.024). Also, strong positive associations between serum S100A1-ZAG, serum adiponectin-ZAG, and serum adiponectin-S100A1 (β>0.800, p<0.001) were shown.

Conclusion

In the present study, we found that low FEV1 was associated with increased risk of cachexia in COPD patients. Additionally, lower serum level of ZAG and higher RMR were observed in patients with severe-very severe COPD as compared to mild-moderate COPD. Therefore, it could be claimed that there is a mechanistic chain of causality between FEV1, serum ZAG, RMR, and cachexia.

BMI is associated with FEV1 decline in chronic obstructive pulmonary disease: a meta-analysis of clinical trials

Background

There is considerable heterogeneity in the rate of lung function decline in chronic obstructive pulmonary disease (COPD), the determinants of which are largely unknown. Observational studies in COPD indicate that low body mass index (BMI) is associated with worse outcomes, and overweight/obesity has a protective effect – the so-called “obesity paradox”. We aimed to determine the relationship between BMI and the rate of FEV₁ decline in data from published clinical trials in COPD.

Methods

We performed a systematic review of the literature, and identified 5 randomized controlled trials reporting the association between BMI and FEV₁ decline. Four of these were included in the meta-analyses. We analyzed BMI in 4 categories: BMI-I (< 18.5 or <  20 kg/m²), BMI-II (18.5 or 20 to < 25 kg/m²), BMI-III (25 to < 29 or < 30 kg/m²) and BMI-IV (≥29 or ≥ 30 kg/m²). We then performed a meta-regression of all the estimates against the BMI category.

Results

The estimated rate of FEV₁ decline decreased with increasing BMI. Meta-regression of the estimates showed that BMI was significantly associated with the rate of FEV₁ decline (linear trend p = 1.21 × 10^− 5).

Conclusions

These novel findings support the obesity paradox in COPD: compared to normal BMI, low BMI is a risk factor for accelerated lung function decline, whilst high BMI has a protective effect. The relationship may be due to common but as-of-yet unknown causative factors; further investigation into which may reveal novel endotypes or targets for therapeutic intervention.

Molecular Characteristics and Treatment of Endothelial Dysfunction in Patients with COPD: A Review Article

Patients with chronic obstructive pulmonary disease (COPD) show systemic consequences, such as chronic systemic inflammation leading to changes in the airway, airway penetrability, and endothelial function. Endothelial dysfunction is characterized by a list of alterations of endothelium towards reduced vasodilation, proinflammatory state, detachment and apoptosis of endothelial cells, and development of atherosclerosis. COPD-induced endothelial dysfunction is associated with elevated cardiovascular risk. The increment of physical activities such as pulmonary rehabilitation (PR) training have a significant effect on COPD, thus, PR can be an integrative part of COPD treatment. In this narrative review the focus is on the function of endothelial inflammatory mediators [cytokines, chemokines, and cellular proteases] and pulmonary endothelial cells and endothelial dysfunction in COPD as well as the effects of dysfunction of the endothelium may play in COPD-related pulmonary hypertension. The relationship between smoking and endothelial dysfunction is also discussed. The connection between different pulmonary rehabilitation programs, arterial stiffness and pulse wave velocity (PWV) is presented. Endothelial dysfunction is a significant prognostic factor of COPD, which can be characterized by PWV. We discuss future considerations, like training programs, as an important part of the treatment that has a favorable impact on the endothelial function.

Circulating adiponectin levels are paradoxically associated with mortality rate. A systematic review and meta-analysis

CONTEXT

Some studies have surprisingly indicated that serum adiponectin is positively related to mortality rate, thus casting doubts on its role as a therapeutic target for cardiovascular disease.

OBJECTIVE

To summarize evidence about direction, strength and modulators of this controversial association.

DATA SOURCES

MEDLINE, Web of Science, CINHAL, Cochrane Library and Scopus from inception through June 2018.

STUDY SELECTION

English-language prospective studies reporting the association between adiponectin and all-cause or cardiovascular mortality.

DATA EXTRACTION

Two investigators independently extracted data and assessed study quality using standard criteria following the Preferred Reporting Items for Systematic Reviews and Meta-analyses and The Newcastle-Ottawa Scale, respectively. Pooled hazard ratios (HRs) (95% confidence intervals-CIs) were derived using a fixed or random effects models when appropriated and were expressed for one standard deviation (SD) increment of adiponectin.

DATA SYNTHESIS

We identified fifty-five (n=61,676 subjects) and twenty-eight (n=43,979 subjects) studies for all-cause and cardiovascular mortality, respectively. Pooled HRs, were 1.24 (1.17-1.31) and 1.28 (1.19-1.37) for all-cause and cardiovascular mortality, respectively. Similar results were obtained also for High Molecular Weight adiponectin. When meta-analyses were restricted to studies reporting data on natriuretic peptides a 43% and 28% reduction on a log scale of these associations were observed after natriuretic peptides adjustment.

CONCLUSIONS

Our results strongly points to a paradoxical association between high adiponectin levels and increased mortality rate, which is partly modulated by natriuretic peptides.

Globular Adiponectin Exerts a Pro-Inflammatory Effect via IκB/NF-κB Pathway Activation and Anti-Inflammatory Effect by IRAK-1 Downregulation

Adiponectin, a hormone produced by adipose tissue, is very abundant in plasma, and its anti- and pro-inflammatory effects are reported. However, the mechanisms of these pro- and anti-inflammatory effects are not fully defined. Herein, we evaluated the dual inflammatory response mechanism of adiponectin in macrophages. Short-term globular adiponectin (gAd) treatment induced IκBα degradation, NF-κB nuclear translocation, and TNF-α production in RAW 264.7 cells. Polymyxin B pretreatment did not block gAd-induced IκBα degradation, and heated gAd was unable to degrade IκBα, suggesting that the effects of gAd were not due to endotoxin contamination. gAd activated IKK and Akt, and inhibition of either IKK or Akt by dominant-negative IKKβ (DN-IKKβ) or DN-Akt overexpression blocked gAd-induced IκBα degradation, suggesting that short-term incubation with gAd mediates inflammatory responses by activating the IκB/NF-κB and PI3K/Akt pathways. Contrastingly, long-term stimulation with gAd induced, upon subsequent stimulation, tolerance to gAd, lipopolysaccharide, and CpG-oligodeoxynucleotide, which is associated with gAd-induced downregulation of IL-receptor-associated kinase-1 (IRAK-1) due to IRAK-1 transcriptional repression. Conclusively, our findings demonstrate that the pro- and anti-inflammatory responses to gAd in innate immune cells are time-dependent, and mediated by the activation of the IκB/NF-κB pathway, and IRAK-1 downregulation, respectively.

The association between circulating adiponectin levels, lung function and adiposity in subjects from the general population; data from the Akershus Sleep Apnea Project

BACKGROUND

Circulating adiponectin (ADPN) levels are inversely associated with disease severity in patients with chronic obstructive pulmonary disease (COPD), while studies assessing the relationship between ADPN and lung function in subjects from the general population have shown diverging results. Accordingly, we hypothesized that ADPN would be associated with lung function in a population-based sample and tested how abdominal adiposity, metabolic syndrome, and systemic inflammation influenced this association.

METHODS

We measured total ADPN in serum, forced vital capacity (FVC) and forced expiratory volume during the 1st second (FEV1) in 529 participants (median 50 years, 54.6% males) recruited from the general population. We assessed the association between ADPN and lung function by multivariate linear regression analyses and adjusted for age, gender, height, smoking habits, weight, body mass index, waist-hip ratio, metabolic syndrome, obstructive sleep apnoea (OSA) and C-reactive protein.

RESULTS

The median (interquartile range) level of serum ADPN was 7.6 (5.4-10.4) mg/L. ADPN levels were positively associated with FVC % of predicted (beta 3.4 per SD adiponectin, p < 0.001)) in univariate linear regression analysis, but the association was attenuated in multivariate analysis (standardized beta 0.03, p = 0.573)). Among co-variates only WHR significantly attenuated the relationship. ADPN levels were also associated with FEV1% of predicted in bivariate analysis that adjusted for smoking (beta 1.4, p = 0.042)), but this association was attenuated and no longer significant in multivariate analysis (standardized beta -0.06, p = 0.254)).

CONCLUSION

In this population-based sample no association between ADPN and lung function was evident after adjustment for covariates related to adiposity.

Lung, Fat and Bone: Increased Adiponectin Associates with the Combination of Smoking-Related Lung Disease and Osteoporosis

Background: Adiponectin has been proposed as a biomarker of disease severity and progression in chronic obstructive pulmonary disease (COPD) and associated with spirometry-defined COPD and with computed tomography (CT)-measured emphysema. Increased adiponectin plays a role in other diseases including diabetes/metabolic syndrome, cardiovascular disease and osteoporosis. Previous studies of adiponectin and COPD have not assessed the relationship of adiponectin to airway disease in smokers and have not evaluated the effect of other comorbid diseases on the relationship of adiponectin and lung disease. We postulated that adiponectin levels would associate with both airway disease and emphysema in smokers with and without COPD, and further postulated that body composition and the comorbid diseases of osteoporosis, cardiovascular disease and diabetes might influence adiponectin levels. Methods: Current and former smokers from the COPD Genetic Epidemiology study (COPDGene) (n= 424) were assigned to 4 groups based on CT lung characteristics and volumetric Bone Density (vBMD). Emphysema (% low attenuation area at -950) and airway disease (Wall area %) were used to assess smoking-related lung disease (SRLD). Group 1) Normal Lung with Normal vBMD; Group 2) Normal Lung and Osteoporosis; Group 3) SRLD with Normal vBMD; Group 4) SRLD with Osteoporosis. Cardiovascular disease (CVD), diabetes, C-reactive protein (CRP) and T-cadherin (soluble receptor for adiponectin) levels were defined for each group. Body composition was derived from chest CT. Multivariable regression assessed effects of emphysema, wall area %, bone density, comorbid diseases and other key factors on log adiponectin. Results: Group 4, SRLD with Osteoporosis, had significantly higher adiponectin levels compared to other groups and the effect persisted in adjusted models. Systemic inflammation (by CRP) was associated with SRLD in Groups 3 and 4 but not with osteoporosis alone. In regression models, lower bone density and worse emphysema were associated with higher adiponectin. Airway disease was associated with higher adiponectin levels when T-cadherin was added to the model. Male gender, greater muscle and fat were associated with lower adiponectin. Conclusions: Adiponectin is increased with both airway disease and emphysema in smokers. Bone density, and fat and muscle composition are all significant factors predicting adiponectin that should be considered when it is used as a biomarker of COPD. Increased adiponectin from chronic inflammation may play a role in the progression of bone loss in COPD and other lung diseases.

The Adiponectin Paradox for All-Cause and Cardiovascular Mortality

Basic science studies have shown beneficial effects of adiponectin on glucose homeostasis, chronic low-grade inflammation, apoptosis, oxidative stress, and atherosclerotic processes, so this molecule usually has been considered a salutary adipokine. It was therefore quite unexpected that large prospective human studies suggested that adiponectin is simply a marker of glucose homeostasis, with no direct favorable effect on the risk of type 2 diabetes and cardiovascular disease. But even more unforeseen were data addressing the role of adiponectin on the risk of death. In fact, a positive, rather than the expected negative, relationship was reported between adiponectin and mortality rate across many clinical conditions, comprising diabetes. The biology underlying this paradox is unknown. Several explanations have been proposed, including adiponectin resistance and the confounding role of natriuretic peptides. In addition, preliminary genetic evidence speaks in favor of a direct role of adiponectin in increasing the risk of death. However, none of these hypotheses are based on robust data, so further efforts are needed to unravel the elusive role of adiponectin on cardiometabolic health and, most important, its paradoxical association with mortality rate.

Plasma Leptin and Reduced FEV1 and FVC in Chronic Spinal Cord Injury

BACKGROUND

Adipose tissue produces leptin, which is pro-inflammatory, and adiponectin, which has anti-inflammatory properties. Participants with chronic spinal cord injury (SCI) have increased body fat and are at increased risk for respiratory illness.

OBJECTIVE

To assess the associations between leptin and adiponectin with pulmonary function in a chronic SCI cohort.

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

A total of 285 participants (237 men and 48 women) with chronic SCI with mean (standard deviation) injury duration 17.8 (13.2) years from the VA Boston and the community participating in an epidemiologic study assessing factors associated with respiratory health.

METHODS

Participants (24.6% cervical American Spinal Injury Association Impairment Scale (AIS) level A, B, and C; 33.6% other AIS A, B, and C; 41.8% AIS D) provided a blood sample, completed a respiratory health questionnaire, and underwent spirometry. Linear regression methods were used to assess cross-sectional associations between plasma leptin and adiponectin with spirometric measures of pulmonary function adjusted for age, race, gender, and height. Level and severity of SCI, mobility mode, body mass index, smoking, chronic obstructive pulmonary disease, asthma, chest injury history, laboratory batch, and other potential confounders were also considered.

MAIN OUTCOME MEASUREMENTS

forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC.

RESULTS

There was a statistically significant inverse relationship between plasma leptin assessed in quartiles or as a continuous covariate with FEV₁ and FVC. In fully adjusted models, each interquartile range (16,214 pg/mL) increase in leptin was associated with a significant decrease in FEV₁ (-93.1 mL; 95% confidence interval = -166.2, -20.0) and decrease in FVC (-130.7 mL; 95% confidence interval = -219.4, -42.0). There were no significant associations between leptin and FEV₁/FVC or between plasma adiponectin with FEV₁, FVC, or FEV₁/FVC.

CONCLUSION

Plasma leptin in individuals with chronic SCI is inversely associated with FEV₁ and FVC, independently of SCI level and severity and other covariates. This finding suggests that plasma leptin may contribute to reduced pulmonary function in chronic SCI.

LEVEL OF EVIDENCE

II.

Different forms of adiponectin reduce the apoptotic and damaging effect of cigarette smoke extract on human bronchial epithelial cells

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease, in which adiponectin may serve an important role. The present study investigated the role of adiponectin in the apoptotic and damaging effect of cigarette smoke extract (CSE) on human bronchial epithelial cells (16HBECs). An MTT assay showed that CSE significantly inhibited the proliferation of 16HBECs (F=1808.88, P<0.01). The 16HBECs were treated with different concentrations of high molecular weight (HMW) adiponectin and globular domain (gAd) adiponectin and it was observed that HMW and gAd dose-dependently inhibited the expression of tumor necrosis factor (TNF)-α and interleukin (IL)-8, and the generation of 4-hydroxy-nonenal and reactive oxygen species (ROS) in 16HBECs, thereby blocking the upregulating effect of CSE on these factors. However, the inhibitory effect of gAd on TNF-α and IL-8 expression was stronger compared with that of HMW, but the suppressing effect of HMW on ROS production was superior compared with that of gAd. Further testing of apoptosis indicated that CSE and HMW promoted the apoptosis of 16HBECs. However, such effects of HMW declined with an increase in concentration. In contrast, gAd showed an inhibitory effect on apoptosis and inhibited the occurrence of CSE-induced apoptosis in a dose-dependent manner. Therefore, the present study demonstrated that different forms of adiponectin may have different mechanisms of action, suggesting that further exploration of their effects may open a new avenue for the treatment of COPD.

Association of plasma adipokines with chronic obstructive pulmonary disease severity and progression

RATIONALE

Two adipokines, leptin and adiponectin, regulate metabolic and inflammatory systems reciprocally. The role of adiponectin in chronic obstructive pulmonary disease (COPD) has been studied. However, there are few data evaluating the relationship of plasma leptin with COPD severity or progression.

OBJECTIVES

The objective of this study was to evaluate the relationship of leptin, adiponectin, and the leptin/adiponectin ratio with COPD severity and progression according to COPD phenotypes.

METHODS

Plasma leptin and adiponectin levels were measured in 196 subjects with COPD selected from the Korean Obstructive Lung Disease cohort. Using a linear regression model and mixed linear regression, we determined the relationship of plasma leptin and adiponectin levels and the leptin/adiponectin ratio to COPD severity and progression over 3 years.

MEASUREMENTS AND MAIN RESULTS

The concentration of adiponectin in plasma positively correlated with percent emphysema on initial computed tomography (CT) (adjusted P = 0.022), whereas plasma leptin concentrations and the leptin/adiponectin ratio exhibited a significant inverse correlation with initial FEV1 (adjusted P = 0.013 for leptin and adjusted P = 0.041 for leptin/adiponectin ratio). Increased plasma leptin and leptin/adiponectin ratio were significantly associated with change in percent emphysema over 3 years (adjusted P = 0.037 for leptin and adjusted P = 0.029 for leptin/adiponectin ratio), whereas none of the adipokines demonstrated an association with FEV1 decline over the 3-year period.

CONCLUSIONS

Plasma adiponectin and leptin vary according to COPD phenotypes. Plasma leptin and the leptin/adiponectin ratio, but not adiponectin, were significantly associated with changes in CT-assessed emphysema, suggesting a potential role as a biomarker in emphysema progression in patients with COPD.

Genetic variants of CDH13 determine the susceptibility to chronic obstructive pulmonary disease in a Chinese population

AIM

Adiponectin has been implicated in the development of chronic obstructive pulmonary disease (COPD). The CDH13 gene encodes T-cadherin that is an adiponectin receptor, and genetic variants of CDH13 determine blood adiponectin levels. The aim of this study was to investigate the effects of CDH13 variants on COPD susceptibility in a Chinese population.

METHODS

Ten single-nucleotide polymorphisms (SNP) in CDH13 were screened using the SNaPshot method in 279 COPD patients and 367 control subjects. Association of genotypes or haplotypes constructed from these loci with COPD was analyzed in different genetic models.

RESULTS

Among the 10 SNPs tested, rs4783244 and rs12922394 exhibited significant differences in allele or genotype frequencies between COPD patients and control subjects, whereas 8 other SNPs did not. The minor allele T was associated with decreased risk of COPD in the recessive model at rs4783244 (OR=0.42, P=0.023) and in the dominant model at rs12922394 (OR=0.70, P=0.022). The genotype TT at either rs4783244 or rs12922394 was associated with a significantly low level of plasma adiponectin when compared to genotypes GG and CC (P<0.05). Haplotypes GC in block 1 (rs4783244-rs12922394) as well as GTAC and ATGT in block 3 (rs4783266-rs11640522-rs11646849-rs11860282) significantly increased the risk of COPD, whereas haplotypes TT in block 1, TG in block 2 (rs11646011- rs11640875) and ATGC in block 3 were protective against COPD.

CONCLUSION

CDH13 genetic variants determine Chinese individuals' susceptibility to COPD and thus are efficient genetic biomarkers for early detection of COPD.

Biomarker Development for Chronic Obstructive Pulmonary Disease. From Discovery to Clinical Implementation

Chronic obstructive pulmonary disease (COPD) is one of the major causes of morbidity and mortality in the world. Regrettably, there are no biomarkers to objectively diagnose COPD exacerbations, which are the major drivers of hospitalization and deaths from COPD. Moreover, there are no biomarkers to guide therapeutic choices or to risk stratify patients for imminent exacerbations and no objective biomarkers of disease activity or disease progression. Although there has been a tremendous investment in COPD biomarker discovery over the past 2 decades, clinical translation and implementation have not matched these efforts. In this article, we outline the challenges of biomarker development in COPD and provide an overview of a developmental pipeline that may be able to surmount these challenges and bring novel biomarker solutions to accelerate therapeutic discoveries and to improve the care and outcomes of the millions of individuals worldwide with COPD.

Lower leptin/adiponectin ratio and risk of rapid lung function decline in chronic obstructive pulmonary disease

RATIONALE

The rate of annual change in FEV1 is highly variable among patients with chronic obstructive pulmonary disease (COPD). Reliable blood biomarkers are needed to predict prognosis.

OBJECTIVES

To explore plasma biomarkers associated with an annual change in FEV1 in patients with COPD.

METHODS

Plasma samples of 261 subjects, all Japanese, with COPD from the 5-year Hokkaido COPD cohort study were analyzed as a hypothesis-generating cohort, and the results were validated using data of 226 subjects with and 268 subjects without airflow limitation, mainly white, from the 4-year COPD Quantification by Computed Tomography, Biomarkers, and Quality of Life (CBQ) study conducted in Denmark. The plasma samples were measured using Human CardiovascularMAP (Myriad RBM, Austin, TX), which could analyze 50 biomarkers potentially linked with inflammatory, metabolic, and tissue remodeling pathways, and single ELISAs were used to confirm the results.

MEASUREMENTS AND MAIN RESULTS

Higher plasma adiponectin levels and a lower leptin/adiponectin ratio at enrollment were significantly associated with an annual decline in FEV1 even after controlling for age, sex, height, and body mass index in the Hokkaido COPD cohort study (P = 0.003, P = 0.004, respectively). A lower plasma leptin/adiponectin ratio was also significantly associated with an annual decline in FEV1 in subjects with airflow limitation in the CBQ study (P = 0.014), the patients of which had largely different clinical characteristics compared with the Hokkaido COPD cohort study. There were no significant associations between lung function decline and adipokine levels in subjects without airflow limitation.

CONCLUSIONS

A lower leptin/adiponectin ratio was associated with lung function decline in patients with COPD in two independent Japanese and Western cohort studies of populations of different ethnicity. Measure of systemic adipokines may provide utility in predicting patients with COPD at higher risk of lung function decline.

The chronic obstructive pulmonary disease comorbidity spectrum in Japan differs from that in western countries

Patients with Chronic Obstructive Pulmonary Disease (COPD) frequently suffer from various comorbidities, such as cardiovascular disease, osteoporosis, depression, malnutrition, metabolic syndrome, diabetes, and lung cancer. These comorbidities have a significant impact on disease severity and survival. In fact, guidelines from both the Global Initiative for Chronic Obstructive Lung Disease and the Japanese Respiratory Society recommend that physicians take comorbidities into account when they evaluate COPD severity. These guidelines also emphasize the importance of managing comorbidities alongside airway obstruction in COPD. The mechanisms by which the many COPD-related comorbidities develop are still unclear. Aging and smoking are well-established as major factors. However, systemic inflammation may also contribute to the disease process. Having developed from the classical theory to differentiate COPD patients into "pink puffers" and "blue bloaters", COPD is now generally considered as a heterogeneous condition. On this point, we have noticed that the characteristics of Japanese COPD patients tend to differ from those of Westerners. Specifically, Japanese patients tend to be older, to have lower body mass index, to suffer from emphysema-dominant lung disease, and to experience exacerbations less frequently. The comorbidity spectrum of Japanese COPD patients also seems to differ from that of Westerners. For instance, in Japanese patients, cardiovascular disease and metabolic syndrome are less prevalent, whereas osteoporosis and malnutrition are more frequent. In order to treat Japanese COPD patients optimally, we must pay particular attention to their unique demographics and comorbidity spectrum, which contrast with those of Western COPD patients.

High circulating adiponectin levels predict decreased muscle strength among older adults aged 70 years and over: A prospective cohort study

BACKGROUND AND AIMS

Population-based researches indicate that circulating adiponectin is inversely associated with muscle strength. However, interpretation of the findings has been limited by the use of a cross-sectional design. This study aimed to examine the prospective relationship between baseline circulating adiponectin concentration and change in muscular function-related physical performance in older adults.

METHODS AND RESULTS

A 1-year prospective cohort study of Japanese community-dwelling elderly was conducted between 2002 and 2003. Four hundred thirty-four older persons participated in the measurements of physical function, including leg extension power, functional reach, timed up-and-go test, and 10-m maximum walking speed, at baseline and follow-up. After adjustment for potential covariates, higher serum adiponectin concentration was found to be significantly associated with poorer physical performance at baseline (leg extension power [watt], P < 0.001; functional reach [cm], P < 0.001; log timed up-and-go test, P = 0.007; log 10-m maximum walking speed, P < 0.001). The results of the prospective analysis by analysis of covariance indicated that the elderly with higher serum adiponectin concentrations (tertiles) at baseline tended to have a decreased performance in leg extension power (means [95% confidence interval]: lowest, -105 [-125, -85.7]; middle, -117 [-135, -97.8]; highest, -140 [-160, -120], watt, P for trend = 0.021) and timed up-and-go test (lowest, -0.08 [-0.28, -0.12]; middle, -0.10 [-0.29, 0.10]; highest, 0.28 [0.07, 0.48], s, P for trend = 0.019), but not two other functioning.

CONCLUSION

High circulating adiponectin concentration may be an indicator of decreased physical performance, especially muscle strength, in older adults.

Nutrition and respiratory health--feature review

Diet and nutrition may be important modifiable risk factors for the development, progression and management of obstructive lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). This review examines the relationship between dietary patterns, nutrient intake and weight status in obstructive lung diseases, at different life stages, from in-utero influences through childhood and into adulthood. In vitro and animal studies suggest important roles for various nutrients, some of which are supported by epidemiological studies. However, few well-designed human intervention trials are available to definitively assess the efficacy of different approaches to nutritional management of respiratory diseases. Evidence for the impact of higher intakes of fruit and vegetables is amongst the strongest, yet other dietary nutrients and dietary patterns require evidence from human clinical studies before conclusions can be made about their effectiveness.

Association between plasma adiponectin levels and decline in forced expiratory volume in 1 s in a general Japanese population: the Takahata study

BACKGROUND

Adiponectin is an anti-inflammatory and cardio-protective cytokine. However, several studies have demonstrated that plasma adiponectin levels were inversely associated with pulmonary function in patients with chronic obstructive pulmonary disease, suggesting a proinflammatory or pulmonary-destructive role. It is still unclear whether adiponectin is a potent biomarker predicting declines in pulmonary function. The aim of this study was to investigate the association between adiponectin and pulmonary function among Japanese individuals who participated in an annual health check-up.

METHODS

Spirometry and blood sampling, including measurements of plasma adiponectin, were performed for 3,253 subjects aged 40 years or older who participated in a community-based annual health check-up in Takahata, Japan from 2004 to 2006. In 2011, spirometry was re-performed, and the data from 872 subjects (405 men and 467 women) were available for a longitudinal analysis.

RESULTS

Plasma adiponectin levels were found to be significantly associated with age, body mass index (BMI), and alanine aminotransferase (ALT), triglycerides (TG), and high-density lipoprotein-cholesterol (HDL-c) levels among both men and women in the study population. Plasma adiponectin levels were found to be associated with lifetime cigarette consumption (Brinkman index, BI) in men only. Plasma adiponectin levels were inversely correlated with forced expiratory volume in 1 s (FEV1) per forced vital capacity in both men and women. In addition, the annual change in FEV1 was inversely associated with plasma adiponectin levels in both genders. A multiple linear regression analysis revealed that this association was independent of other confounding factors such as age, BMI, BI, ALT, TG, and HDL-c.

CONCLUSIONS

The results of the present study suggest that adiponectin levels are predictive of declines in FEV1 in the general population.

Lungs, bone marrow, and adipose tissue. A network approach to the pathobiology of chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) often suffer other concomitant disorders, such as cardiovascular diseases and metabolic disorders, that influence significantly (and independently of lung function) their health status and prognosis. Thus, COPD is not a single organ condition, and disturbances of a complex network of interorgan connected responses occur and modulate the natural history of the disease. Here, we propose a novel hypothesis that considers a vascularly connected network with (1) the lungs as the main external sensor of the system and a major source of "danger signals"; (2) the endothelium as an internal sensor of the system (also a potential target tissue); and (3) two key responding elements, bone marrow and adipose tissue, which produce both inflammatory and repair signals. According to the model, the development of COPD, and associated multimorbidities (here we focus on cardiovascular disease as an important example), depend on the manner in which the vascular connected network responds, adapts, or fails to adapt (dictated by the genetic and epigenetic background of the individual) to the inhalation of particles and gases, mainly in cigarette smoke. The caveats and limitations of the hypothesis, as well as the experimental and clinical research needed to test and explore the proposed model, are also briefly discussed.

Biomarkers in COPD

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease that cannot be described by the severity of airflow limitation (forced expiratory volume in the first second of expiration) only. Other measures are needed in clinical practice to assess patients, predict their risk, guide their treatment, and assess their response to it. Over the past few years, there has been a great deal of interest in the identification and validation of biomarkers of potential clinical use in COPD. Here, the authors review some general concepts in the field, discuss currently validated biomarkers in COPD, and speculate on potential future developments.

Adiponectin, Leptin, and Resistin in Asthma: Basic Mechanisms through Population Studies

Adipokines, factors produced by adipose tissue, may be proinflammatory (such as leptin and resistin) or anti-inflammatory (such as adiponectin). Effects of these adipokines on the lungs have the potential to evoke or exacerbate asthma. This review summarizes basic mechanistic data through population-based and clinical studies addressing the potential role of adipokines in asthma. Augmenting circulating concentrations of adiponectin attenuates allergic airway inflammation and airway hyperresponsiveness in mice. Murine data is supported by human data that suggest that low serum adiponectin is associated with greater risk for asthma among women and peripubertal girls. Further, higher serum total adiponectin may be associated with lower clinical asthma severity among children and women with asthma. In contrast, exogenous administration of leptin results in augmented allergic airway hyperresponsiveness in mice. Alveolar macrophages obtained from obese asthmatics are uniquely sensitive to leptin in terms of their potential to augment inflammation. Consistent with this basic mechanistic data, epidemiologic studies demonstrate that higher serum leptin is associated with greater asthma prevalence and/or severity and that these associations may be stronger among women, postpubertal girls, and prepubertal boys. The role of adipokines in asthma is still evolving, and it is not currently known whether modulation of adipokines may be helpful in asthma prevention or treatment.

Adiponectin: an attractive marker for metabolic disorders in Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory lung disease which may be complicated by development of co-morbidities including metabolic disorders. Metabolic disorders commonly associated with this disease contribute to lung function impairment and mortality. Systemic inflammation appears to be a major factor linking COPD to metabolic alterations. Adipose tissue seems to interfere with systemic inflammation in COPD patients by producing a large number of proteins, known as “adipokines”, involved in various processes such as metabolism, immunity and inflammation. There is evidence that adiponectin is an important modulator of inflammatory processes implicated in airway pathophysiology. Increased serum levels of adiponectin and expression of its receptors on lung tissues of COPD patients have recently highlighted the importance of the adiponectin pathway in this disease. Further, in vitro studies have demonstrated an anti-inflammatory activity for this adipokine at the level of lung epithelium. This review focuses on mechanisms by which adiponectin is implicated in linking COPD with metabolic disorders.

The association of adiponectin with computed tomography phenotypes in chronic obstructive pulmonary disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder associated with systemic manifestations that contribute to its morbidity and mortality. Recent work suggests that biomarker signatures in the blood may be useful in evaluating COPD phenotypes and may provide insight into the pathophysiology of systemic manifestations. Adiponectin, primarily produced by fat cells, has been implicated in the pathophysiology of emphysema.

OBJECTIVES

To investigate the association of adiponectin with clinical and radiologic COPD phenotypes.

METHODS

Adiponectin levels were determined in 633 individuals, including 432 individuals with COPD from a cohort of former or current smokers enrolled in the COPDGene study. Univariate and multiple regression analysis were used to examine the association of adiponectin with clinical and physiologic data together with quantitative high-resolution computed tomography parameters.

MEASUREMENTS AND MAIN RESULTS

Multiple regression analysis confirmed that higher plasma adiponectin levels were independently associated with emphysema, decreasing body mass index, female sex, older age, and lower percentage change in prebronchodilator/post-bronchodilator FEV1.

CONCLUSIONS

The association between plasma adiponectin and computed tomography-assessed emphysema suggests a contribution of adiponectin to the development of emphysema and highlights a role for metabolic derangements in the pathophysiology of emphysema.

Genetic variations in ADIPOQ gene are associated with chronic obstructive pulmonary disease

BACKGROUND

Adiponectin is reported to be related to the development of chronic obstructive pulmonary disease (COPD). Genetic variants in the gene encoding adiponectin (ADIPOQ) have been reported to be associated with adiponectin level in several genome-wide linkage and association studies. However, relatively little is known about the effects of ADIPOQ gene variants on COPD susceptibility. We determined the frequencies of single-nucleotide polymorphisms (SNPs) in ADIPOQ in a Chinese Han population and their possible association with COPD susceptibility.

METHODS

We conducted a case-control study of 279 COPD patients and 367 age- and gender-distribution-matched control subjects. Seven tagging SNPs in ADIPOQ, including rs710445, rs16861205, rs822396, rs7627128, rs1501299, rs3821799 and rs1063537 were genotyped by SNaPshot. Association analysis of genotypes/alleles and haplotypes constructed from these loci with COPD was conducted under different genetic models.

RESULTS

The alleles or genotypes of rs1501299 distributed significantly differently in COPD patients and controls (allele: P = 0.002, OR = 1.43 and 95%CI = 1.14-1.79; genotype: P = 0.008). The allele A at rs1501299 was potentially associated with an increased risk of COPD in all dominant model analysis (P = 0.009; OR: 1.54; 95%CI: 1.11-2.13), recessive model analyses (P = 0.015; OR: 1.75; 95% CI: 1.11-2.75) and additive model analyses (P = 0.003; OR: 2.11; 95% CI: 1.29-3.47). In haplotype analysis, we observed haplotypes AAAAACT and GGACCTC had protective effects, while haplotypes AGAACTC, AGGCCTC, GGAACTC, GGACACT and GGGCCTC were significantly associated with the increased risk of COPD.

CONCLUSIONS

We conducted the first investigation of the association between the SNPs in ADIPOQ and COPD risk. Our current findings suggest that ADIPOQ may be a potential risk gene for COPD. Further studies in larger groups are warranted to confirm our results.

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.