Lack of matrix metalloproteinase-9 worsens ventilator-induced lung injury

2008 ◽  
Vol 294 (3) ◽  
pp. L535-L543 ◽  
Author(s):  
Guillermo M. Albaiceta ◽  
Ana Gutiérrez-Fernández ◽  
Diego Parra ◽  
Aurora Astudillo ◽  
Emilio García-Prieto ◽  
...  

Matrix metalloproteinase-9 (MMP-9) is released by neutrophils at the sites of acute inflammation. This enzyme modulates matrix turnover and inflammatory response, and its activity has been found to be increased after ventilator-induced lung injury. To clarify the role of MMP-9, mice lacking this enzyme and their wild-type counterparts were ventilated for 2 h with high- or low-peak inspiratory pressures (25 and 15 cmH2O, respectively). Lung injury was evaluated by gas exchange, respiratory mechanics, wet-to-dry weight ratio, and histological analysis. The activity of MMP-9 and levels of IL-1β, IL-4, and macrophage inflammatory protein (MIP-2) were measured in lung tissue and bronchoalveolar lavage fluid (BALF). Cell count and myeloperoxidase activity were measured in BALF. There were no differences between wild-type and Mmp9−/− animals after low-pressure ventilation. After high-pressure ventilation, wild-type mice exhibited an increase in MMP-9 in tissue and BALF. Mice lacking MMP-9 developed more severe lung injury than wild-type mice, in terms of impaired oxygenation and lung mechanics, and higher damage in the histological study. These effects correlated with an increase in both cell count and myeloperoxidase activity in the BALF, suggesting an increased neutrophilic influx in response to ventilation. An increase in IL-1β and IL-4 in the BALF only in knockout mice could be responsible for the differences. There were no differences between genotypes in MMP-2, MMP-8, or tissue inhibitors of metalloproteinases. These results show that MMP-9 protects against ventilator-induced lung injury by decreasing alveolar neutrophilic infiltration, probably by modulation of the cytokine response in the air spaces.

Author(s):  
Е.В. Маркелова ◽  
О.В. Овчинникова ◽  
А.С. Хохлова ◽  
Л.П. Догадова ◽  
А.В. Костюшко ◽  
...  

Оперативное вмешательство - один из основных методов лечения глаукомы. Однако развитие избыточного рубцевания созданных путей оттока определяет результат хирургического лечения в отдаленные сроки. Процессы рубцевания на данный момент недостаточно изучены. Цель исследования - оценка роли матриксной металлопротеиназы-9, ее ингибиторов в процессах рубцевания у больных с первичной открытоугольной глаукомой после оперативного лечения. Методика. Для выявления возможных маркеров избыточного рубцевания методом твердофазного иммуноферментного анализа определяли содержание матриксных металлопротеиназ-9, тканевых ингибиторов металлопротеиназ 2 и -3 в слезной жидкости у 37 пациентов с активной стадией первичной остроугольной глаукомы в динамике послеоперационного периода. Средний возраст пациентов составил 52,8 лет. В зависимости от исхода оперативного вмешательства все пациенты были разделены на 2 группы - с благоприятным исходом (без избыточного рубцевания) и с неблагоприятным исходом (с избыточным рубцеванием) на месте сформированных дополнительных путей оттока внутриглазной жидкости в послеоперационном периоде. Группа контроля включала 20 человек в возрасте от 50 до 66 лет без сопутствующей офтальмологической и соматической патологии в стадии обострения. Результаты. В динамике показано изменение концентрации матриксной металлопротеиназы-9 и ее ингибиторов в послеоперационном периоде. Анализ данных свидетельствует об обратной зависимости уровня матриксной металлопротеиназы-9 и тканевых ингибиторов металлопротеиназы 2 и 3 типов с исходом операции - чем выше концентрация металлопротеиназы-9 и ниже концентрация тканевых ингибиторов металлопротеиназ 2, -3 в слезной жидкости, тем выше вероятность неблагоприятного исхода в виде рубцевания сформированных дополнительных путей оттока внутриглазной жидкости в послеоперационном периоде. Заключение. Мониторинг уровня металлопротеиназ и их тканевых ингибиторов после проведения хирургического лечения пациентов с первичной открытоугольной глаукомой позволяет прогнозировать раннее рубцевание, дает возможность разработки новых методов лечения как в раннем, так и в позднем послеоперационном периоде. Surgery is one of the major treatments for glaucoma; however excessive scarring of created outflow patways affects the long-term outcome. At the present time, scarring processes are not sufficiently studied. Aim. To evaluate the role of matrix metalloproteinase 9 and its inhibitors in scarring after surgical treatment of open-angle glaucoma. Methods. Concentrations of matrix metalloproteinase 9 and tissue inhibitors of metalloproteinases 2 and 3 were measured in tear fluid of 37 patients (mean age, 52.8) with active primary open-angle glaucoma in dynamics during the postoperative period to identify possible markers of excessive scarring. Based on the surgery outcome, all patients were divided into two groups, with a favorable outcome (without excessive scarring) and an unfavorable outcome (with excessive scarring) in the created additional outflow pathways for the intraocular fluid in the postoperative period. The control group included 20 subjects aged 50-66 without eye disease or somatic disease at exacerbation stage. Results. Analysis of changes in concentrations of matrix metalloproteinase 9 and its inhibitors in the postoperative period showed their inverse relationship with the surgery outcome. The higher was the metalloproteinase 9 level and the lower the level of tissue inhibitors of metalloproteinases 2 and 3 the higher was the probability of unfavorable outcome evident as excessive scarring of the formed additional pathways for tear fluid outflow in the postoperative period. Conclusion. Postoperative monitoring of metalloproteinases and their tissue inhibitors allows to predict early scarring and to develop new treatments both in early and late postoperative periods.


2006 ◽  
Vol 291 (4) ◽  
pp. L580-L587 ◽  
Author(s):  
Je Hyeong Kim ◽  
Min Hyun Suk ◽  
Dae Wui Yoon ◽  
Seung Heon Lee ◽  
Gyu Young Hur ◽  
...  

Neutrophils are considered to play a central role in ventilator-induced lung injury (VILI). However, the pulmonary consequences of neutrophil accumulation have not been fully elucidated. Matrix metalloproteinase-9 (MMP-9) had been postulated to participate in neutrophil transmigration. The purpose of this study was to investigate the role of MMP-9 in the neutrophilic inflammation of VILI. Male Sprague-Dawley rats were divided into three groups: 1) low tidal volume (LVT), 7 ml/kg of tidal volume (VT); 2) high tidal volume (HVT), 30 ml/kg of VT; and 3) HVT with MMP inhibitor (HVT+MMPI). As a MMPI, CMT-3 was administered daily from 3 days before mechanical ventilation. Degree of VILI was assessed by wet-to-dry weight ratio and acute lung injury (ALI) scores. Neutrophilic inflammation was determined from the neutrophil count in the lung tissue and myeloperoxidase (MPO) activity in the bronchoalveolar lavage fluid (BALF). MMP-9 expression and activity were examined by immunohistochemical staining and gelatinase zymography, respectively. The wet-to-dry weight ratio, ALI score, neutrophil infiltration, and MPO activity were increased significantly in the HVT group. However, in the HVT+MMPI group, pretreatment with MMPI decreased significantly the degree of VILI, as well as neutrophil infiltration and MPO activity. These changes correlated significantly with MMP-9 immunoreactivity and MMP-9 activity. Most outcomes were significantly worse in the HVT+MMPI group compared with the LVT group. In conclusion, VILI mediated by neutrophilic inflammation is closely related to MMP-9 expression and activity. The inhibition of MMP-9 protects against the development of VILI through the downregulation of neutrophil-mediated inflammation.


2009 ◽  
Vol 77 (7) ◽  
pp. 2643-2649 ◽  
Author(s):  
Andrew J. Heilpern ◽  
Warren Wertheim ◽  
Jia He ◽  
George Perides ◽  
Roderick T. Bronson ◽  
...  

ABSTRACT Borrelia burgdorferi, the causative agent of Lyme arthritis, does not produce any exported proteases capable of degrading extracellular matrix despite the fact that it is able to disseminate from a skin insertion site to infect multiple organs. Prior studies have shown that B. burgdorferi induces the host protease, matrix metalloproteinase 9 (MMP-9), and suggested that the induction of MMP-9 may allow the organism to disseminate and produce local tissue destruction. We examined the role of MMP-9 in dissemination of B. burgdorferi and pathogenesis of Lyme arthritis. In a MMP-9−/− mouse model, MMP-9 was not required for the dissemination of the spirochete to distant sites. However, MMP-9−/− exhibited significantly decreased arthritis compared to wild-type mice. The decrease in arthritis was not due to an inability to control infection since the spirochete numbers in the joints were identical. Levels of inflammatory chemokines and cytokines were also similar in MMP-9−/− and wild-type mice. We examined whether decreased inflammation in MMP-9−/− mice may be the result of decreased production of neoattractants by MMP-9-dependent cleavage of collagen. MMP-9 cleavage of type I collagen results in increased monocyte chemoattraction. MMP-9 plays an important role in regulating inflammation in Lyme arthritis, potentially through the cleavage of type I collagen.


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