Opinion Article - Journal of Pulmonology and Clinical Research (2023) Volume 6, Issue 3
The role of matrix metalloproteases in emphysema progression
Department of pulmonary, University of Rome Tor Vergata, Rome, Italy
- *Corresponding Author:
- Gloria Francesco
Department of pulmonary,
University of Rome Tor Vergata,
Received:24-Apr-2023, Manuscript No. AAJPCR-23-98189; Editor assigned: 27-Apr-2023, PreQC No. AAJPCR-23-98189(PQ); Reviewed:11-May-2023, QC No. AAJPCR-23-98189; Revised:15-May-2023, Manuscript No. AAJPCR-23-98189(R); Published:22-May-2023, DOI:10.35841/aajpcr-6.3.146
Citation: Francesco G. The role of matrix metalloproteases in emphysema progression. J Pulmonol Clin Res. 2023;6(3):146
Emphysema is a chronic obstructive pulmonary disease (COPD) that is characterized by the destruction of lung tissue and the enlargement of air spaces. The disease is often caused by cigarette smoking, but can also be caused by exposure to air pollution, dust, or chemical fumes. Emphysema can lead to significant respiratory impairment, and is a major cause of morbidity and mortality worldwide. The pathogenesis of emphysema involves the destruction of the extracellular matrix (ECM) of the lung tissue, which is mediated by a group of enzymes called matrix metalloproteases (MMPs). In this article, we will explore the role of MMPs in emphysema progression. MMPs are a family of zinc-dependent endopeptidases that are involved in the degradation and remodeling of the ECM. They are produced by a variety of cells, including epithelial cells, fibroblasts, and inflammatory cells. MMPs are synthesized as inactive precursors, or proMMPs, which are then activated by proteolytic cleavage. Once activated, MMPs degrade various components of the ECM, including collagen, elastin, and proteoglycans .
In emphysema, the destruction of the ECM is primarily caused by the activation of MMP-2, MMP-9, and MMP-12. MMP-2 and MMP-9 are gelatinases that specifically degrade type IV collagen, which is a major component of the basement membrane of the alveolar epithelium. MMP-12, also known as macrophage elastase, is secreted by macrophages and targets elastin, a key component of the alveolar walls. These three MMPs have been shown to be elevated in the lung tissue of patients with emphysema, as well as in animal models of the disease. The activation of MMPs in emphysema is mediated by a variety of factors, including cigarette smoke, oxidative stress, and inflammatory cytokines. Cigarette smoke is a major risk factor for emphysema, and has been shown to induce the expression and activation of MMP-2, MMP-9, and MMP-12 in the lung tissue. Cigarette smoke also increases oxidative stress in the lung, which can activate MMPs by cleaving their prodomains. Inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), are produced by inflammatory cells in the lung tissue and can also induce the expression of MMPs .
The activation of MMPs in emphysema leads to the destruction of the ECM, which results in the enlargement of air spaces and the loss of alveolar surface area. The loss of alveolar surface area reduces the surface area available for gas exchange, which impairs lung function and leads to shortness of breath. The destruction of the ECM also impairs the ability of the lung tissue to repair itself, which can exacerbate the progression of the disease. The role of MMPs in emphysema progression has been extensively studied in animal models of the disease. Studies have shown that the inhibition of MMP-2, MMP-9, and MMP-12 can attenuate the development of emphysema in animal models. For example, the administration of an MMP-12 inhibitor to mice exposed to cigarette smoke was shown to reduce the extent of emphysema and improve lung function. Similarly, the inhibition of MMP-9 in a mouse model of emphysema was shown to reduce the destruction of the ECM and improve lung function .
These findings suggest that MMPs play a critical role in the pathogenesis of emphysema, and that the inhibition of MMP activity may represent a potential therapeutic strategy for the treatment of the disease in humans. However, clinical trials of MMP inhibitors in emphysema have been disappointing thus far. One reason for this is that MMPs have multiple functions in the body, and the inhibition of MMP activity can have unintended consequences. For example, the inhibition of MMPs has been associated with impaired wound healing, and an increased risk of cancer metastasis. Another reason for the lack of success in clinical trials may be that MMP inhibitors have not been targeted to the appropriate patient population. Emphysema is a heterogeneous disease, and the activation of MMPs may be more important in certain subtypes of the disease. Identification of the appropriate patient population for MMP inhibition may be critical for the success of future clinical trials .
In addition to MMP inhibition, other therapeutic strategies for emphysema are being explored. These include stem cell therapy, gene therapy, and anti-inflammatory therapies. Stem cell therapy involves the transplantation of stem cells into the lung tissue to promote tissue regeneration. Gene therapy involves the transfer of genes into the lung tissue to promote the expression of protective proteins. Anti-inflammatory therapies target the inflammatory response in the lung tissue, which can reduce the activation of MMPs .
Matrix metalloproteases play a critical role in the progression of emphysema. The activation of MMP-2, MMP-9, and MMP-12 leads to the destruction of the ECM, which results in the enlargement of air spaces and the loss of alveolar surface area. While MMP inhibition has shown promise in animal models of the disease, clinical trials of MMP inhibitors in humans have been disappointing thus far. Further research is needed to identify the appropriate patient population for MMP inhibition, and to develop targeted therapies that can improve the outcomes for patients with emphysema.
- Pizov R.A randomized trial comparing lung-volume-reduction surgery with medical therapy for severe emphysema. Surv Anesthesiol. 2004;48(1):55-6.
- Thurlbeck WM, Simon G.Radiographic appearance of the chest in emphysema. Am J Roentgeno. 1978;130(3):429-40.
- Sciurba FC, Ernst A, Herth FJ, et al.A randomized study of endobronchial valves for advanced emphysema. N Engl J Med. 2010;363(13):1233-44.
- Leopold JG, Gough J.The centrilobular form of hypertrophic emphysema and its relation to chronic bronchitis. Thorax. 1957;12(3):219.
- Tashkin DP, Roth MD.Pulmonary effects of inhaled cannabis smoke. Am J Drug Alcohol Abuse. 2019;45(6):596-609.