Metalloproteinases and their Inhibitors under the Course of Immunostimulation by CPG-ODN and Specific Antigen Inhalation in Equine Asthma

Abstract

Objectives. Inhalation of immunostimulatory bacterial DNA segments (cytosine-phosphate-guanosine-oligodeoxynucleotides, CpG-ODN) normalizes clinical and cytologic parameters in severe equine asthma. We hypothesized that CpG-ODN inhalation also reduces the misbalance of elastinolytic activity in asthmatic horses. Methods. Twenty asthmatic horses diagnosed by clinical examinations using a scoring system were included. All horses inhaled CpG-ODNs for 14 days in 2-day intervals. Matrix metalloproteinase (MMP-2/-9) and tissue inhibitors of metalloproteinase (TIMP-1/-2) concentrations were measured in tracheal aspirates using equine sandwich ELISAs before and 2 and 6 weeks after CpG-ODN inhalation. Results. MMP and TIMP concentrations correlated with the results of clinical scoring in all stages of equine asthma. Inhalation therapy led to significant reductions in clinical scores. MMP-2, MMP-9, and TIMP-2 concentrations were significantly reduced immediately, and all MMP and TIMP concentrations 6 weeks after therapy. Discussion. In equine asthma, overexpression of MMPs contributes to pathological tissue destruction, while TIMPs counteract MMPs with overexpression leading to fibrosis formation. The results of this study show that CpG-ODN inhalation may be an effective therapy to address a misbalance in equine asthma. Conclusions. Misbalance of elastinolytic activity seems to improve by CpG-ODN inhalation for at least 6 weeks posttherapy, which may reduce the remodeling of the extracellular matrix. Further studies should evaluate this effect in comparison to glucocorticoid inhalation therapy. Significance. CpG-ODN inhalation may be an effective therapy in the prevention of pulmonary fibrosis formation in equine asthma.

Equine Asthma – Update on terminology, diagnosis and therapy

“…Darüber hinaus wird die Aufnahme mittels Endozytose in die Zielzellen gesteigert und damit die Wirkung der CpG deutlich optimiert (Zwiorek et al 2008). Das klinischtherapeutische Potential von CpG-ODNs wurde in den letzten Jahren in mehreren Feldstudien bestätigt (Klier et al 2012, 2019, Barton et al 2019. Der Effekt wurde jedoch bisher noch nicht über einen längeren Zeitraum als 8 Wochen und noch nicht für das MEA untersucht (Couëtil et al 2016).…”

Inhalative Nanoparticulate CpG Immunotherapy in Severe Equine Asthma: An Innovative Therapeutic Concept and Potential Animal Model for Human Asthma Treatment

“…The ability of GNP to serve as an effective molecular transport system for CpG-ODN in equine BAL cells was confirmed [ 74 ]. The previously identified CpG-ODN sequence was administered in subsequent in vivo studies to horses with severe equine asthma and was thereby examined for its local and systemic tolerability and its therapeutic effect on clinical and immunological parameters [ 75 , 76 , 77 , 78 , 79 ].…”

“…In severe equine asthma, increased matrix metalloproteinase (MMP) expression contributes to pathological pulmonary tissue damage, while tissue inhibitors of metalloproteinases (TIMPs) combat MMP overexpression and pulmonary fibrosis (reviewed by [ 79 ]). Barton et al [ 79 ] showed that CpG-GNP inhalation presents a possible effective therapy that can work against the imbalance in MMP and TIMP expression in pulmonary tissue in severe equine asthma.…”

“…In severe equine asthma, increased matrix metalloproteinase (MMP) expression contributes to pathological pulmonary tissue damage, while tissue inhibitors of metalloproteinases (TIMPs) combat MMP overexpression and pulmonary fibrosis (reviewed by [ 79 ]). Barton et al [ 79 ] showed that CpG-GNP inhalation presents a possible effective therapy that can work against the imbalance in MMP and TIMP expression in pulmonary tissue in severe equine asthma. Matrix metalloproteinases (MMP-2/MMP-9) and tissue inhibitors of metalloproteinase (TIMP-1/TIMP-2) concentrations were determined in tracheal wash sampling by equine ELISAs before and two and six weeks after CpG-GNP inhalation [ 79 ].…”

“…Barton et al [ 79 ] showed that CpG-GNP inhalation presents a possible effective therapy that can work against the imbalance in MMP and TIMP expression in pulmonary tissue in severe equine asthma. Matrix metalloproteinases (MMP-2/MMP-9) and tissue inhibitors of metalloproteinase (TIMP-1/TIMP-2) concentrations were determined in tracheal wash sampling by equine ELISAs before and two and six weeks after CpG-GNP inhalation [ 79 ]. MMP-2, MMP-9, and TIMP-2 concentrations were significantly decreased directly after the treatment as well as six weeks post-treatment [ 79 ].…”