Adult stem cells for chronic lung diseases
Official Journal of the Asian Pacific Society of Respirology
Respirology (2013) 18, 1041–1046 doi: 10.1111/resp.12112
ANA L. MORA2,3 AND MAURICIO ROJAS1,2,4
Idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) are chronic, progressive and lethal lung diseases. The incidence of IPF and COPD increases with age, independent of exposure to common environmental risk factors. At present, there is limited understanding of the relationship between ageing and the development of chronic lung diseases. One hypothesis is that chronic injury drives to exhaustion the local and systemic repair responses in the lung. These changes are accentuated during ageing where there is a progressive accumulation of senescent cells. Recently, stem cells have emerged as a critical reparative mechanism for lung injury. In this review, we discuss the repair response of bone marrow‐derived mesenchymal stem cells (B‐MSC) after lung injury and how their function is affected by ageing. Our own work has demonstrated a protective role of B‐MSC in several animal models of acute and chronic lung injury. We recently demonstrated the association, using animal models, between age and an increase in the susceptibility to develop severe injury and fibrosis. At the same time, we have identified functional differences between B‐MSC isolated from young and old animals. Further studies are required to understand the functional impairment of ageing B‐MSC, ultimately leading to a rapid stem cell depletion or fatigue, interfering with their ability to play a protective role in lung injury. The elucidation of these events will help in the development of rational and new therapeutic strategies for COPD and IPF.
As a self‐repair mechanism, living organisms have stem cells that are attracted to sites of injury. Chronic injury as well as ageing could exhaust and impair stem cell reparative capacity as well as diminish number of available stem cells. The mechanism(s) by which alterations in the homeostasis of stem cells pools are involved in the pathogenesis of chronic lung diseases is unknown. If stem cell exhaustion and ageing is the cause of morbid states, stem cell‐based therapies will be able to prevent and treat them. Restoration of stem cells has shown promising therapeutic benefits for certain lung pathologies. Particularly, the immunomodulatory capacity of B‐MSC has been shown to be beneficial for lung diseases with exacerbated inflammatory responses. However, a generalized use of B‐MSC in chronic lung diseases must be considered with caution, and careful studies are still required to establish safety and efficacy of such use.