Correlation of circulating MMP-9 with white blood cell count in humans: effect of smoking

The usefulness of MMP-9, TIMP-1 and MMP-9/TIMP-1 ratio for diagnosis and assessment of COPD severity

BACKGROUND

Inflammation, oxidative stress and an imbalance between proteases and protease inhibitors are recognized pathophysiological features of chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate serum levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in patients with COPD and to assess their relationship with lung function, symptom severity scores and recent acute exacerbations.

METHODS

In this observational cohort study, serum levels of MMP-9 and TIMP-1 and the MMP-9/TIMP-1 ratio in the peripheral blood of COPD patients with stable disease and healthy controls were determined, and their association with lung function (postbronchodilator spirometry, body plethysmography, single breath diffusion capacity for carbon monoxide), symptom severity scores (mMRC and CAT) and exacerbation history were assessed.

RESULTS

COPD patients (n = 98) had significantly higher levels of serum MMP-9 and TIMP-1 and a higher MMP-9/TIMP-1 ratio than healthy controls (n = 47) (p ≤ 0.001). The areas under the receiver operating characteristic curve for MMP-9, TIMP-1 and the MMP-9/TIMP-1 ratio for COPD diagnosis were 0.974, 0.961 and 0.910, respectively (all p < 0.05). MMP-9 and the MMP-9/TIMP-1 ratio were both negatively correlated with FVC, FEV_1, FEV₁/FVC, VC, and IC (all p < 0.05). For MMP-9, a positive correlation was found with RV/TLC% (p = 0.005), and a positive correlation was found for the MMP-9/TIMP-1 ratio with RV% and RV/TLC% (p = 0.013 and 0.002, respectively). Patients with COPD GOLD 3 and 4 presented greater MMP-9 levels and a greater MMP-9/TIMP-1 ratio compared to GOLD 1 and 2 patients (p ≤ 0.001). No correlation between diffusion capacity for carbon monoxide and number of acute exacerbations in the previous year was found.

CONCLUSIONS

COPD patients have elevated serum levels of MMP-9 and TIMP-1 and MMP-9/TIMP-1 ratio. COPD patients have an imbalance between MMP-9 and TIMP-1 in favor of a pro-proteolytic environment, which overall indicates the importance of the MMP-9/TIMP-1 ratio as a potential biomarker for COPD diagnosis and severity.

Smoking Induces the Circulating Levels of Matrix Metalloproteinase-9 and Its Association with Cardiovascular Risk in Young Smokers

Objective

Smoking causes cardiovascular risk, which may alter the stability between the production and degradation of the extracellular matrix. Matrix metalloproteinase-9 (MMP-9) is a zinc-containing endopeptidase that degrades the extracellular matrix and is involved in tissue remodelling and several physiological processes. As a result, smoking-induced elevated serum MMP-9 levels, particularly at a younger age, raise the risk of coronary heart disease (CHD). Thus, this study aimed to determine the possible relationship between smoking-induced circulating MMP-9 and the risk of cardiovascular disease in young smokers.

Methods

In this cross-sectional study, the patients were divided into three groups. Each group contains 120 study participants. Group one consisted of 120 healthy individuals with no physical and mental illness, group two consisted of 120 active smokers with a heart disease, and group three consisted of 120 active smokers with a heart disease and diabetes, who attended Sri Ramaswamy Memorial Hospital for cardiology checkup at the age of 20-55 years. The serum MMP-9, high-sensitivity C-reactive protein (hs-CRP), and apolipoprotein-E (APO-E) levels were analyzed using the ELISA method, and the lipid levels were measured enzymatically using AU480 automatic analyzer (Beckman Coulter).

Results

Compared with non-smokers, the study shows that the mean serum MMP-9, hs-CRP, and APO-E levels were significantly higher in smokers (p<0.001). A strong relationship was also found between MMP-9 and hs-CRP, APO-E, smoking load, and smoking intensity.

Conclusions

A significant association was found between cigarette smoking with MMP-9, and relative exposure to circulating inflammation markers plays a potential role in the pathogenesis of CHD.

The role of LCN2 and LCN2-MMP9 in spondylitis radiographic development: gender and HLA-B27 status differences

Background

Male HLA-B27-positive radiographic-axial spondyloarthritis (r-axSpA) patients are prone to have severe spinal radiographic progression, but the underlying mechanisms are unclear. We recently showed that persistently elevated Lipocalin 2 (LCN2; L) reflects sacroiliac joint (SIJ) inflammation. LCN2 binds to MMP9. Concomitant elevation of L and LCN2-MMP9 (LM) was detected in many inflammatory diseases. We asked whether L and LM play similar roles in r-axSpA pathogenesis.

Methods

We analyzed 190 axSpA patients (123 radiographic and 67 non-radiographic axSpA) who had no detectable circulating Oncostatin M, to avoid complications due to cross-talk between pathways. L and LM levels from a single blood sample of each patient were measured and were correlated with MRI and modified stoke AS (mSASS) scoring. Association of elevated L (L+) or concurrent L+ and elevated LM (LM+) patterns with B27 status and gender were assessed.

Results

In L+LM+ axSpA patients, both L and LM levels correlated with MRI SPARCC SIJ scores, but only LM levels correlated with MRI Berlin Spine Scores, suggesting LM is a biomarker for both SIJ and spinal inflammation. Among patients with minimal spinal ankylosis (mSASSS < 10), 65% of male r-axSpA patients are L+LM+, while 30% and 64% of female patients are L+LM+ and L+, respectively, supporting the role of LM with disease progression. In B27+ L+LM+ male patients, both L and LM (but not CRP) levels correlate with mSASSS. B27 positivity and maleness have additive effects on spondylitis progression, suggesting concurrent high L and LM elevations are associated with B27+ male patients having more significant radiographic damage. L+ B27-negative male patients or L+ female patients are more likely to have milder disease.

Conclusion

L and LM are informative biomarkers for SIJ and spinal inflammation, as well as for ankylosing development in r-axSpA patients. Distinctive L+LM+ or L+ patterns not only could distinguish clinically aggressive vs milder course of disease, respectively, but also provide an explanation for B27-positive male patients being the most susceptible to severe ankylosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02854-2.

Matrix Metalloproteinase 9 Blood Alterations in Patients With Schizophrenia Spectrum Disorders: A Systematic Review and Meta-Analysis

BACKGROUND

Matrix metalloproteinase 9 (MMP-9), an extracellular network protease implicated in glutamatergic signaling, may be part of the pathophysiology of schizophrenia spectrum disorders (SSD).

METHODS

We performed a systematic review in PubMed/Embase until July 15, 2020, conducting a random-effects meta-analysis of studies comparing MMP-9 blood levels in SSD vs healthy controls (HCs) and psychiatric controls (PCs), calculating between-group differences in standardized mean differences (SMDs) ± 95% confidence intervals (CIs). Meta-regression analyses included sex, age, illness duration, antipsychotic dose, and Positive and Negative Syndrome Scale (PANSS) total/subscales. Subgroup analyses included first-episode patients (FEP) vs non-FEP, each vs HCs and vs PCs, and blood sample type. Study quality was assessed using the Newcastle-Ottawa scale.

RESULTS

Four, five, and two trials were rated as high, fair, and low quality. In 11 studies (n = 1443), 643 patients (age = 36.7 ± 14.1 years, females = 42.9%) were compared with HCs (n = 631), with 4 studies including also 169 PCs. MMP-9 levels were higher in SSD vs HCs (SMD = 0.52, 95%CI = 0.20-0.85, P = .002), but not in PCs vs HCs (n = 132, after removing one implausible outlier [SMD = 0.33, 95%CI = -0.16 to 0.85, P = .082]). MMP-9 differences between SSD and HCs were associated with higher PANSS total (coefficient = 0.02, 95%CI = 0.01-0.02, P < .001), PANSS positive (coefficient = 0.08, 95%CI = 0.02-0.13, P = .006), and PANSS general scores (coefficient = 0.02, 95%CI = 0.01-0.03, P < .001). MMP-9 level differences vs HCs did not vary significantly between FEP (n = 103, SMD = 0.44, 95%CI = 0.15-0.72, P = .71) and non-FEP patients (n = 466, SMD = 0.59, 95%CI = 0.38-0.80; P = .34) (FEP vs non-FEP: P = .39). In four high-quality studies, MMP-9 levels remained significantly higher in SSD vs HCs (SMD = 0.82, 95%CI = 0.03-1.61).

CONCLUSIONS

Findings suggest MMP-9 upregulation in SSD, requiring further validation and understanding of related pathways.

Immunological axis of berberine in managing inflammation underlying chronic respiratory inflammatory diseases

Inflammatory responses play a remarkable role in the mechanisms of acute and chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, pulmonary fibrosis and lung cancer. Currently, there is a resurgence in the use of drugs from natural sources for various ailments as potent therapeutics. Berberine, an alkaloid prominent in the Chinese traditional system of medicine has been reported to exert therapeutic properties in various diseases. Nevertheless, the number of studies focusing on the curative potential of berberine in inflammatory diseases involving the respiratory system is limited. In this review, we have attempted to discuss the reported anti-inflammatory properties of berberine that function through several pathways such as, the NF-κB, ERK1/2 and p38 MAPK pathways which affect several pro-inflammatory cytokines in the pathophysiological processes involved in chronic respiratory diseases. This review would serve to provide valuable information to researchers who work in this field and a new direction in the field of drug discovery with respect to respiratory diseases.

Matrix metalloproteinases (MMPs) and inhibitor of metalloproteinases (TIMP) mRNA and protein expression in laryngeal squamous cell carcinoma

INTRODUCTION

The aim of the study was to investigate the mRNA expression and protein levels of matrix metalloproteinases (MMP) 2 (MMP-2), 9 (MMP-9), 7 (MMP-7) and their tissue inhibitor TIMP-2 in patients with laryngeal squamous cell carcinoma and control subjects and additionally to evaluate a possible correlation with clinicopathological features.

MATERIAL AND METHODS

The expression levels of MMP-2, MMP-9, MMP-7, and TIMP-2 mRNA were detected by the real-time quantitative real time polymerase chain reaction method in 96 cases of laryngeal carcinoma vs. non-tumor tissue. The blood serum levels of MMP-2, MMP-9, MMP-7, and TIMP-2 in patients with laryngeal cancer and 100 healthy subjects were measured using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The present study demonstrated that MMP-2, MMP-7, MMP-9 and TIMP-2 mRNA expression levels in carcinoma tissue vs. non-tumor tissue and protein levels in the preoperative serum vs. those obtained in healthy controls were statistically significantly higher than in the healthy controls (p = 0.001). The only significant correlation between mRNA or concentration of measured MMPs and TIMP and the clinicopathological features was found for TIMP-2 protein and for patients with lymph node metastasis. Serum levels of TIMP-2 were higher in cases with lymph node metastasis than in those without lymph node metastasis (p < 0.05).

CONCLUSIONS

The results may suggest that MMPs and TIMP-2 are associated with laryngeal tumorigenesis, but we did not find any distinct correlation between the clinicopathological features of laryngeal squamous cell carcinoma patients and expression levels of MMPs and TIMP. The results suggest that the measurement of serum MMP-2, MMP-7, MMP-9 and TIMP-2 concentration might be helpful to diagnose laryngeal squamous cell carcinoma.

Outcome of patients with and poor prognostic factors for Mycobacterium kansasii-pulmonary disease

BACKGROUND

Aggressive therapy for Mycobacterium kansasii-pulmonary disease (MK-PD) is recommended because of the virulence of MK. However, some clinicians may be concerned regarding the lengthy course and numerous adverse effects. This study evaluated the natural course of MK-PD and investigated its prognostic factors.

METHODS

Radiographic outcome, prognostic factors, and mortality within 1 year for MK-PD were obtained from patients in 6 hospitals in Taiwan from 2010 to 2014 (derivation cohort) and validated using patients in 2015 and 2016 (validation cohort).

RESULTS

Of the 109 patients with MK-PD in the derivation cohort, radiographic progression occurred in 70 (64%), with a 1-year mortality rate of 43% and median survival of 71 days, whereas none of the 39 cases without radiographic progression died. All patients with acid-fast smear (AFS) grade ≥ 3 experienced radiographic progression. For the others, the independent risk factors of radiographic progression were fibroCavitary pattern, Leucocyte count >9000/μL, Old age (age >65 years), pUre MK in sputum (no other mycobacteria), and no Diabetes mellitus (the CLOUD factors). By applying these criteria to the validation cohort (n = 112), 3 (9%) of the 33 patients with MK-PD who initially had AFS grade < 3 and < 3 CLOUD risk factors experienced radiographic progression, and none of the 3 died of MK-PD.

CONCLUSIONS

Because of the high risk of radiographic progression and subsequent fatal outcome, immediate anti-MK treatment is recommended. For patients with MK-PD who have sputum AFS grade <3 and < 3 CLOUD risk factors, regular follow-up may be an alternative.

Review of the role of cigarette smoking in diabetic foot

Diabetic foot ulceration has been a serious issue over the past decades in Asia, causing economic and social problems. Therefore, it is important to identify and reduce the risk factors of diabetic foot. Cigarette smoking has been reported to be associated with diabetes and its macrovascular complications, but the relationship between smoking and diabetic foot ulcers is still unclear. In the present review, we summarize the effects of cigarette smoking on diabetic foot ulcers with respect to peripheral neuropathy, vascular alterations and wound healing. One underlying mechanism of these impacts might be the smoking-induced oxidative stress inside the cells. At the end of this review, the current mainstream therapies for smoking cessation are also outlined. We believe that it is urgent for all diabetic patients to quit smoking so as to reduce their chances of developing foot ulcers and to improve the prognosis of diabetic foot ulcers.

Effects of Tobacco Usage and Antiretroviral Therapy on Biomarkers of Systemic Immune Activation in HIV-Infected Participants

Like HIV infection, smoking, which is common among HIV-infected persons, is associated with chronic, systemic inflammation. However, the possible augmentative effects of HIV infection and smoking and other types of tobacco usage on indices of systemic inflammation and the impact of combination antiretroviral therapy (cART) thereon remain largely unexplored and represent the focus of the current study. Of the total number of HIV-infected persons recruited to the study (n = 199), 100 were categorised as pre-cART and 99 as virally suppressed (HIV viral load < 40 copies/mL). According to serum cotinine levels, 144 and 55 participants were categorised as nonusers and users of tobacco, respectively. In addition to cytokines (IL-6, IL-8, and TNF-α) and chemokines (IP-10, MIG, IL-8, MCP-1, and RANTES), other biomarkers of systemic inflammation included C-reactive protein (CRP), β2-microglobulin, and those of neutrophil activation [ICAM-1, L-selectin, matrix metalloproteinase-9 (MMP-9)], microbial translocation (soluble CD14, LPS-binding protein), and oxidative stress (cyclophilin A, surfactant D). These were measured using multiplex bead array, ELISA, and immunonephelometric procedures. Viral suppression was associated with significant decreases in the levels of most of the biomarkers tested (P < 0.0037-0.0008), with the exceptions of CRP, cyclophilin A, and MMP-9. With respect to tobacco usage, irrespective of cART status, circulating levels of β2-microglobulin, cyclophilin A, and RANTES were significantly elevated (P < 0.042-0.012) in users vs nonusers. Additional analysis of the groups of tobacco users and nonusers according to cART status revealed high levels of RANTES in pre-cART/tobacco users relative to the three other subgroups (P < 0.004-0.0001), while more modest increases in cyclophilin A and MMP-9 (P < 0.019-0.027) were observed in comparison with the cART/tobacco user subgroup. Notwithstanding the efficacy of cART in attenuating HIV-associated, chronic systemic inflammation, the current study has identified RANTES as being significantly and seemingly selectively increased in those with active HIV infection who use tobacco, a mechanism which may underpin augmentative proinflammatory activity.

The Association of Biomarkers of Inflammation and Extracellular Matrix Degradation With the Risk of Abdominal Aortic Aneurysm: The ARIC Study

Animal and human laboratory studies suggest that the pathogenesis of abdominal aortic aneurysms (AAAs) involves inflammation and degradation and remodeling of the extracellular matrix. This study prospectively assessed the association between biomarkers for these mechanisms and the presence of AAA during 24 years of follow-up in the Atherosclerosis Risk in Communities (ARIC) study. The ARIC prospectively identified clinically diagnosed AAAs in 15 792 men and women from baseline in 1987 to 1989 to 2011 using hospital discharge codes and death records. Additional asymptomatic AAAs were detected by an abdominal ultrasound scan in 2011 to 2013. Matrix metalloproteinase (MMP)-3, MMP-9, interleukin 6 (IL-6), N-terminal propeptide of Type III procollagen (PIIINP), and osteopontin were measured in blood samples collected between 1987 and 1992 in participants with AAA (544 clinically diagnosed AAAs and 72 ultrasound-detected AAAs) and a random sample of 723 participants selected from baseline and matched with AAAs by age, race and sex. Higher concentrations of MMP-9 and IL-6 were associated with future risk of clinically diagnosed AAA (hazard ratios [95% confidence intervals]: 1.55 [1.22-1.97] and 1.87 [1.48-2.35], respectively, comparing highest versus lowest tertiles) after multivariable adjustment ( P for trend < .001). Matrix metalloproteinase-9 was also associated with ultrasound-detected AAA. In conclusion, blood concentrations of MMP-9 and IL-6 measured in middle age predicted the risk of AAA during 24 years of follow-up.

Biomarkers of Epileptogenesis: The Focus on Glia and Cognitive Dysfunctions

The need to find measures that reliably predict the onset of epilepsy after injurious events or how the patient will respond to anti-seizure drugs led to intensive pre-clinical and clinical research to discover non-invasive biomarkers that could increase the sensitivity of existing clinical indicators. The use of experimental models of epileptogenesis and of drug-resistance is instrumental to select the most promising approaches to explore such biomarkers in the pre-clinical setting for further clinical validation. The approaches most frequently used to find clinically useful biomarkers of epileptogenesis include molecular brain imaging, EEG signal analysis and the measure of soluble molecules in biofluids which may reflect brain intrinsic events involved in epilepsy development. Among those, we focused our attention on proton magnetic resonance imaging (¹H-MRS)-based analysis of astrocytic activation, and related blood biomarkers, since this cell population appears to be pivotally involved in various epileptogenesis processes triggered by differing insults. Moreover, we also investigated behavioral biomarkers by focusing on cognitive dysfunctions since this deficit represents a typical co-morbidity in epilepsy which may manifest even before the onset of spontaneous seizures. In this review article, we will report our recently published evidence supporting the utility of measuring astrocyte activation, the soluble molecules they release, and the associated cognitive deficits during epileptogenesis for early stratification of animals developing epilepsy. We will discuss the potential clinical translation of our findings for enriching the patient population in preventive clinical trials designed to study anti-epileptogenic treatments.

Impact of matrix metalloproteinase 9 rs3918242 genetic variant on lipid-lowering efficacy of simvastatin therapy in Chinese patients with coronary heart disease

Background

Genetic variation of matrix metalloproteinase 9 (MMP-9) gene polymorphism has been suggested to modulate coronary heart diseases (CHD), yet the underlying mechanisms are not well understood.

Methods

We investigated the association of MMP9 rs3918242 single nucleotide polymorphism with inflammation and lipid-lowering efficacy after simvastatin treatment in Chinese patients with CHD. Fasting serum lipid profile and plasma inflammatory mediators were determined at baseline in 264 patients with CHD and 186 healthy control subjects, and after HMG-CoA reductase inhibitor simvastatin treatment (20 mg/day) for 12 weeks in CHD subjects.

Results

We found that plasma MMP-9, TNF-α and IL-10 levels were significantly elevated in patients with CHD compared to control subjects before treatment. The plasma MMP9 in CHD patients carrying rs3918242 CC, CT and TT genotypes were comparable. Interestingly, CHD patients carrying TT genotype had significantly higher level of triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) than those carrying CC genotype (P <0.05). Simvastatin treatment significantly reduced LDL-C, TG and plasma inflammatory mediator levels in CHD patients. The reduction of LDL-C upon simvastatin therapy was significantly greater in patients carrying TT genotype than those carrying CC genotype (P <0.05).

Conclusions

MMP9 rs3918242 TT genotype is associated with elevated serum TG and LDL-C, and enhanced LDL-C-lowering response upon simvastatin treatment in Chinese patients with CHD.

Clinical trial registration

This study was retrospectively registered at Chinese Clinical Trial Registry (Registration number: ChiCTR-ROC-17010971) on March 23^rd 2017.

Protective effect of HwangRyunHaeDok-Tang water extract against chronic obstructive pulmonary disease induced by cigarette smoke and lipopolysaccharide in a mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Hwangryunhaedok-tang is an oriental herbal formula treated to cure inflammation and gastric disorders in China, Japan, and Korea. We explored the protective effects of Hwangryunhaedok-tang water extract (HRWE) against airway pathophysiological changes caused by cigarette smoke (CS) and lipopolysaccharide (LPS) in a mouse.

MATERIALS AND METHODS

We performed quantitative analyses of five marker components, namely geniposide, baicalin, coptisine, plamatine, and berberine, using high-performance liquid chromatography. Animals were received CS exposure (1h per day) for 7 days. LPS was administered intranasally on day 4. Mice were received HRWE at dose of 100 or 200mg/kg for 1h before CS exposure.

RESULTS

Treatment with HRWE significantly suppressed the increased inflammatory cell count induced by CS and LPS exposure. In addition, reduction in IL-6, TNF-α and IL-1β in broncho-alveolar lavage fluid (BALF) was observed after HRWE treatment. HRWE not only decreased inflammatory cell infiltration in lung, but also decreased the expression of iNOS, NF-κB and matrix metallopeptidase (MMP)-9 in lung tissues.

CONCLUSION

This study showed that HRWE can attenuate respiratory inflammation caused by CS and LPS exposure. Therefore, HRWE has potential for treating airway inflammatory disease.

Concomitant elevations of MMP-9, NGAL, proMMP-9/NGAL and neutrophil elastase in serum of smokers with chronic obstructive pulmonary disease

A growing body of evidence points towards smoking‐related phenotypic differences in chronic obstructive pulmonary disease (COPD). As COPD is associated with systemic inflammation, we determined whether smoking status is related to serum levels of matrix metalloproteinase‐9 (pro‐ and active MMP‐9), neutrophil gelatinase‐associated lipocalin (NGAL) and the proMMP‐9/NGAL complex in patients with COPD. Serum samples were collected in 100 stable‐phase COPD patients (82 smokers, 18 never‐smokers) and 28 healthy adults (21 smokers, 7 never‐smokers). Serum levels of studied factors were measured in ELISA. Our data provide the first evidence of simultaneously elevated serum levels of MMP‐9, NGAL and proMMP‐9/NGAL in COPD smokers. While the triad discriminated between smokers and non‐smokers in the COPD group, MMP‐9 and proMMP‐9/NGAL (but not NGAL) discriminated between smokers with and without COPD. Adjustment for age and smoking pack‐years did not alter the findings. Serum MMP‐9, NGAL and proMMP‐9/NGAL levels were not correlated with the GOLD stage or FEV1 decline. Furthermore, serum levels of neutrophil elastase (NE) and MMP‐3 (but not of IL‐6 and MMP‐12) were also higher in COPD smokers than in healthy smokers before and after adjustment for age and pack‐years. Among COPD smokers, levels of MMP‐9, NGAL and proMMP‐9/NGAL were positively correlated with NE (P < 0.0001) but not with the remaining factors. Gelatin zymography detected proMMP‐9 in serum samples of healthy and COPD smoking groups. Our results suggest that associated serum levels of proMMP‐9, NGAL, proMMP‐9/NGAL and NE may reflect the state of systemic inflammation in COPD related to cigarette smoking.

Bronchoabsorption; a novel bronchoscopic technique to improve biomarker sampling of the airway

Background

Current techniques used to obtain lung samples have significant limitations and do not provide reproducible biomarkers of inflammation. We have developed a novel technique that allows multiple sampling methods from the same area (or multiple areas) of the lung under direct bronchoscopic vision. It allows collection of mucosal lining fluid and bronchial brushing from the same site; biopsy samples may also be taken. The novel technique takes the same time as standard procedures and can be conducted safely.

Methods

Eight healthy smokers aged 40–65 years were included in this study. An absorptive filter paper was applied to the bronchial mucosa under direct vision using standard bronchoscopic techniques. Further samples were obtained from the same site using bronchial brushings. Bronchoalveolar lavage (BAL) was obtained using standard techniques. Chemokine (C-C Motif) Ligand 20 (CCL20), CCL4, CCL5, Chemokine (C-X-C Motif) Ligand 1 (CXCL1), CXCL8, CXCL9, CXCL10, CXCL11, Interleukin 1 beta (IL-1β), IL-6, Vascular endothelial growth factor (VEGF), Matrix metalloproteinase 8 (MMP-8) and MMP-9 were measured in exudate and BAL. mRNA was collected from the bronchial brushings for gene expression analysis.

Results

A greater than 10 fold concentration of all the biomarkers was detected in lung exudate in comparison to BAL. High yield of good quality RNA with RNA integrity numbers (RIN) between 7.6 and 9.3 were extracted from the bronchial brushings. The subset of genes measured were reproducible across the samples and corresponded to the inflammatory markers measured in exudate and BAL.

Conclusions

The bronchoabsorption technique as described offers the ability to sample lung fluid direct from the site of interest without the dilution effects caused by BAL. Using this method we were able to successfully measure the concentrations of biomarkers present in the lungs as well as collect high yield mRNA samples for gene expression analysis from the same site. This technique demonstrates superior sensitivity to standard BAL for the measurement of biomarkers of inflammation. It could replace BAL as the method of choice for these measurements. This method provides a systems biology approach to studying the inflammatory markers of respiratory disease progression.

Trial registration

NHS Health Research Authority (13/LO/0256).