Wioletta Zagórska

Airway Remodeling in Chronic Obstructive Pulmonary Disease and Asthma: the Role of Matrix Metalloproteinase-9

Chronic obstructive pulmonary disease (COPD) and asthma are both associated with airflow restriction and progressive remodeling, which affect the respiratory tract. Among various biological factors involved in the pathomechanisms of both diseases, proteolytic enzymes—matrix metalloproteinases (MMPs)—play an important role, especially MMP-9. In this review, the authors discuss the current topics of research concerning the possible role of MMP-9 in both mentioned diseases. They include the analysis of protein levels, nucleotide polymorphisms of MMP-9 gene and their possible correlation with asthma and COPD. Finally, the authors refer to the studies on MMP-9 inhibition as a new perspective for increasing the effectiveness of treatment in asthma and COPD.

Prolonged Treatment with Inhaled Corticosteroids does not Normalize High Activity of Matrix Metalloproteinase-9 in Exhaled Breath Condensates of Children with Asthma.

The airway remodeling in asthma is associated with increased amount of matrix metalloproteinase (MMP)-9. High levels of MMP-9 were found in mucosal biopsies, sputum and in exhaled breath condensates (EBC) of asthma patients. However, there are no data concerning real in vivo activity. Inhaled corticosteroids are effective in asthma control, but it is unclear, whether they only attenuate inflammation, or also protect against progressive remodeling of respiratory tract. Therefore, the aim of the study was to assess the amount and activity of MMP-9 in context of pro-inflammatory cytokines (IL-6, IL-8 and tumor necrosis factor, TNF), measured in EBC of asthma-suffering children, treated with inhaled steroids. The study involved 27 children with asthma, continuously treated with inhaled fluticasone propionate, and 22 healthy controls. In addition to routine clinical screening, the selected cytokines in EBC were analyzed using Ultrasensitive ELISA, whereas activity of MMP-9 was assessed using a novel immunozymography method. Despite chronic treatment with inhaled steroids mean MMP-9/EBC activity in asthma group was significantly higher than in healthy controls. Moreover, high MMP-9/EBC in asthma-suffering children significantly correlated with IgE serum levels. The IL-6 and IL-8 concentration was below the detection limit in all EBC samples. TNF/EBC levels were similar in both, asthma and healthy children. We hypothesize that MMP-9 hyperactivity in asthma may be closely related to high IgE serum levels. Our results suggest that inhaled steroids may be ineffective to prevent asthma-associated airway remodeling. Finally, we emphasize the necessity of further research focused on MMP-9 inhibition in asthma treatment.

Nitric oxide, IL-6 and IL-13 are increased in the exhaled breath condensates of children with allergic rhinitis.

To evaluate nitric oxide and interleukin (IL)‐6, IL‐8 and IL‐13 in the exhaled breath of children with allergic rhinitis (AR), before and after intranasal allergen exposure.

Inhaled corticosteroids do not reduce initial high activity of matrix metalloproteinase (MMP)-9 in exhaled breath condensates of children with asthma exacerbation: a proof of concept study

Inhaled corticosteroids (ICS) are the key component of asthma treatment. However, it is unclear whether they could control the activity and level of matrix metalloproteinase (MMP)-9, which is an important factor in asthma-associated inflammation and airway remodeling. Therefore, the aim of this proof of concept study was to analyze the influence of increased doses of ICS on MMP-9 in exhaled breath condensates (EBC) of patients with allergic asthma exacerbation. Apart from MMP-9, the assessment concerned selected inflammation markers – exhaled nitric oxide (eNO) and cytokines (IL-8 and TNF). The study involved a small group (n = 4) of individuals with asthma exacerbation. The intervention concerned increased doses of ICS with β-mimetics for 4 weeks. In addition to clinical evaluation, eNO measurements and EBC collections were done before and after 4 weeks of intense ICS treatment. The biochemical assessment of EBC concerned MMP-9, IL-8 and TNF. The data were compared to results of healthy controls (n = 6). The initial levels of eNO, MMP-9 and TNF in EBC were higher in the asthma group than in controls. In all subjects IL-8 levels were below the detection limit. After 4 weeks of ICS treatment in all patients we observed improvement of clinical and laboratory parameters. Interestingly, despite reduction of eNO and TNF, the activity of MMP-9/EBC remained on the initial level. Practical relevance of our results is limited by a small group. Nevertheless, our data suggest that ICS, although sufficient to control symptoms and inflammatory markers, may be ineffective to reduce MMP-9/EBC activity in asthma exacerbation and, possibly, airway remodeling.

Polymorphic Variants 279R and 668Q Augment Activity of Matrix Metalloproteinase-9 in Breath Condensates of Children with Asthma

Matrix metalloproteinase (MMP)-9 is involved in pathophysiology of asthma, mainly asthma-associated airway remodeling. Exhaled breath condensates (EBC) of asthmatics contain increased amounts of MMP-9 with activity higher, than in healthy controls. The increased activity of MMP-9 may originate from its excessive production and activation, but may also result from variations in MMP-9 structure, which are determined by single nucleotide polymorphisms (SNPs). In this pilot study we aimed to assess the possible influence of two functional MMP-9 polymorphisms, Q279R and R668Q, on enzymatic activity of MMP-9, measured in EBC of asthmatic children. The concentration and activity of MMP-9 were analyzed in EBC of 20 children with allergic asthma using specific standard ELISA and novel immunoenzymatic activity assay. The SNPs of MMP-9 were assessed using real-time PCR-based genotyping test. We have found that MMP-9 concentration in breath condensates of children with stable asthma was slightly higher in ELISA, than in the activity assay. Moreover, these results and activity-to-amount ratio have revealed some relationship with a presence of specific 279R and/or 668Q MMP-9 gene variants. Our observation suggests that at least in some patients MMP-9 hyperactivity may result from genetic predisposition, determined by polymorphic variants of MMP-9 gene. Moreover, it supports previous reports postulating significance of MMP-9 in pathogenesis of asthma. However, this issue still requires further studies.

Increased angiogenic factors in exhaled breath condensate of children with severe asthma - New markers of disease progression?

Asthma progression is associated with airway remodeling and neo-vascularization. However, role of angiogenesis in these changes remains unclear and available data still incomplete. In this pilot study we verify usefulness of proteome profiler assay in screening of angiogenesis-related factors in exhaled breath condensates (EBC) collected from children with asthma. EBC samples from patients with mild or severe asthma and healthy controls were tested using protein array. In EBC samples from patients with severe asthma we have found large quantities of several angiogenesis regulators, including thrombospondin (TSP)-1, angiogenin, dipeptidyl peptidase (DPP) IV, matrix metalloproteinase (MMP)-9 and its inhibitor TIMP-1. Small amounts of angiopoietin (Ang)-2 and vascular endothelial growth factor (VEGF) were also present. In contrast to them, in EBC from mild asthma group we have detected TSP-1 and small quantities of Ang-2. EBC samples from healthy controls contained only TSP-1. Our preliminary report suggests that, since increased amounts of angiogenesis-related factors in EBC seem to correlate with asthma severity, they may be considered as convenient non-invasive markers of disease progression. However, further research is necessary.

Matrix Metalloproteinases in Asthma-Associated Airway Remodeling – Dr. Jekyll or Mr. Hyde ?

Matrix metalloproteinases (MMPs) are Zn2+-dependent endoproteases, which digest extracellular matrix (ECM) components and various non-ECM molecules. Main physiological role of MMPs concerns regulation of tissue remodeling and regenera‐ tion. The production and activity of MMPs are tightly supervised by multistage control mechanisms. These mechanisms include regulation of gene expression, and various post-transcriptional/post-translational modifications. However, without proper control MMPs reveal dual nature, similarly to character from the novella by R.L. Stevenson, “Strange Case of Dr Jekyll and Mr Hyde”. They become dangerous molecules, involved in cancer metastasis, or cardiovascular diseases. Recent studies revealed that MMPs are also engaged in asthma. Despite extensive research, exact role of MMPs in this process remains unclear and there is no agree‐ ment among scientists, regarding two opposite concepts. The followers of “destruc‐ tive hypothesis” postulate detrimental effect of MMPs on mucosa. Accordingly, MMPsmediated damage stimulates chaotic regeneration, and progressive remodeling. Oppositely, enthusiasts of “protective hypothesis” postulate that MMPs actually do not allow formation of excessive collagen deposits, and thus they protect from tissue fibrosis. The better understanding of “MMPs — Jekyll or Hyde ?” story may be clinically relevant, especially while considering therapies focused on modulation of MMPs activity. Therefore, this issue requires instant elucidation.

Dlaczego dzieci kaszlą przewlekle? Analiza przyczyn kaszlu przewlekłego wśród dzieci hospitalizowanych w Klinice Pneumonologii i Alergologii Wieku Dziecięcego I Katedry Pediatrii WUM w latach 2006–2009

Streszczenie Kaszel jest jednym z najczestszych objawow zglaszanych lekarzowi pierwszego kontaktu. Wedlug wytycznych British Thoracic Society przewlekly kaszel mozna rozpoznac u dzieci, jeśli objaw ten trwa powyzej 8 tygodni. Moze wystepowac u dzieci ogolnie zdrowych po przebyciu niektorych ostrych infekcji drog oddechowych, ale moze byc rowniez glownym symptomem powaznych chorob ukladu oddechowego (kaszel swoisty). Znaczący problem stanowi rowniez tzw. izolowany kaszel nieswoisty – uporczywy, nieslabnący suchy kaszel u dzieci, u ktorych zarowno w badaniu przedmiotowym, jak i w podstawowych badaniach dodatkowych nie znajduje sie zadnych nieprawidlowości. Cel Analiza przyczyn kaszlu przewleklego u dzieci hospitalizowanych w Klinice Pneumonologii i Alergologii Wieku Dzieciecego WUM oraz ocena przydatności w praktyce klinicznej wytycznych BTS. Material i metody Badaniem objeto 105 dzieci, ktore zostaly przyjete do Kliniki w celu diagnostyki przewleklego kaszlu. Przeanalizowano dane anamnestyczne z badania przedmiotowego i wyniki szczegolowych badan dodatkowych i ustalono ostateczne rozpoznania. Wyniki Najczestszą przyczyną kaszlu u badanych dzieci byl tzw. kaszel z gornych drog oddechowych, ktory rozpoznano u 63 pacjentow, na drugim miejscu znalazl sie kaszel poinfekcyjny (27), nastepnie w kolejności malejącej: niedobor odporności (8), astma oskrzelowa (6), refluks zolądkowo-przelykowy(4), wada drog oddechowych i kaszel psychogenny (po 2), sarkoidoza (1). U 5 pacjentow rozpoznano rownolegle 2 przyczyny kaszlu, u 1 z dzieci – 3. Wnioski Najczestszą przyczyną kaszlu przewleklego (powyzej 8 tygodni) u dzieci jest kaszel z gornych drog oddechowych. Zalecenia BTS dotyczące diagnostyki kaszlu przewleklego u dzieci są przydatne w praktyce klinicznej.