MSCs relieve lung injury of COPD mice through promoting proliferation of endogenous lung stem cells

Melatonin and mesenchymal stem cells co-administration alleviates chronic obstructive pulmonary disease via modulation of angiogenesis at the vascular-alveolar unit

Chronic obstructive pulmonary disease (COPD) is considered a severe disease mitigating lung physiological functions with high mortality outcomes, insufficient therapy, and pathophysiology pathways which is still not fully understood. Mesenchymal stem cells (MSCs) derived from bone marrow play an important role in improving the function of organs suffering inflammation, oxidative stress, and immune reaction. It might also play a role in regenerative medicine, but that is still questionable. Additionally, Melatonin with its known antioxidative and anti-inflammatory impact is attracting attention nowadays as a useful treatment. We hypothesized that Melatonin may augment the effect of MSCs at the level of angiogenesis in COPD. In our study, the COPD model was established using cigarette smoking and lipopolysaccharide. The COPD rats were divided into four groups: COPD group, Melatonin-treated group, MSC-treated group, and combined treated group (Melatonin-MSCs). We found that COPD was accompanied by deterioration of pulmonary function tests in response to expiratory parameter affection more than inspiratory ones. This was associated with increased Hypoxia inducible factor-1α expression and vascular endothelial growth factor level. Consequently, there was increased CD31 expression indicating increased angiogenesis with massive enlargement of airspaces and thinning of alveolar septa with decreased mean radial alveolar count, in addition to, inflammatory cell infiltration and disruption of the bronchiolar epithelial wall with loss of cilia and blood vessel wall thickening. These findings were improved significantly when Melatonin and bone marrow-derived MSCs were used as a combined treatment proving the hypothesized target that Melatonin might augment MSCs aiming at vascular changes.

Chronic obstructive pulmonary disease and asthma: mesenchymal stem cells and their extracellular vesicles as potential therapeutic tools

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are one of the most frequent causes of morbidity and mortality in the global. COPD is characterized by progressive loss of lung function through inflammation, apoptosis, and oxidative stress caused by chronic exposure to harmful environmental pollutants. Airway inflammation and epithelial remodeling are also two main characteristics of asthma. In spite of extensive efforts from researchers, there is still a great need for novel therapeutic approaches for treatment of these conditions. Accumulating evidence suggests the potential role of mesenchymal stem cells (MSCs) in treatment of many lung injuries due to their beneficial features including immunomodulation and tissue regeneration. Besides, the therapeutic advantages of MSCs are chiefly related to their paracrine functions such as releasing extracellular vesicles (EVs). EVs comprising exosomes and microvesicles are heterogeneous bilayer membrane structures loaded with various lipids, nucleic acids and proteins. Due to their lower immunogenicity, tumorigenicity, and easier management, EVs have appeared as favorable alternatives to stem cell therapies. Therefore, in this review, we provided an overview on the current understanding of the importance of MSCs and MSC-derived EVs from different sources reported in preclinical and clinical COPD and asthmatic models.

Effect of mesenchymal stromal cell infusions on lung function in COPD patients with high CRP levels

Background

We previously reported a Phase 1/2 randomized placebo-controlled trial of systemic administration of bone marrow-derived allogeneic MSCs (remestemcel-L) in COPD. While safety profile was good, no functional efficacy was observed. However, in view of growing recognition of effects of inflammatory environments on MSC actions we conducted a post-hoc analysis with stratification by baseline levels of a circulating inflammatory marker, C-reactive protein (CRP) to determine the effects of MSC administration in COPD patients with varying circulating CRP levels.

Methods

Time course of lung function, exercise performance, patient reported responses, and exacerbation frequency following four monthly infusions of remestemcel-L vs. placebo were re-assessed in subgroups based on baseline circulating CRP levels.

Results

In COPD patients with baseline CRP ≥ 4 mg/L, compared to COPD patients receiving placebo (N = 17), those treated with remestemcel-L (N = 12), demonstrated significant improvements from baseline in forced expiratory volume in one second, forced vital capacity, and six minute walk distance at 120 days with treatment differences evident as early as 10 days after the first infusion. Significant although smaller benefits were also detected in those with CRP levels ≥ 2 or ≥ 3 mg/L. These improvements persisted variably over the 2-year observational period. No significant benefits were observed in patient reported responses or number of COPD exacerbations between treatment groups.

Conclusion

In an inflammatory environment, defined by elevated circulating CRP, remestemcel-L administration yielded at least transient meaningful pulmonary and functional improvements. These findings warrant further investigation of potential MSC-based therapies in COPD and other inflammatory pulmonary diseases.

Trial registration: Clinicaltrials.gov NCT00683722.

Stem Cell Therapy for COPD: Hope and Exploitation

COPD is a chronic inflammatory and destructive disease characterized by progressive decline in lung function that can accelerate with aging. Preclinical studies suggest that mesenchymal stem cells (MSCs) may provide a therapeutic option for this incurable disease because of their antiinflammatory, reparative, and immunomodulatory properties. To date, clinical trials using MSCs demonstrate safety in patients with COPD. However, because of the notable absence of large, multicenter randomized trials, no efficacy or evidence exists to support the possibility that MSCs can restore lung function in patients with COPD. Unfortunately, the investigational status of cell-based interventions for lung diseases has not hindered the propagation of commercial businesses, exploitation of the public, and explosion of medical tourism to promote unproven and potentially harmful cell-based interventions for COPD in the United States and worldwide. Patients with COPD constitute the largest group of patients with lung disease flocking to these unregulated clinics. This review highlights the numerous questions and concerns that remain before the establishment of cell-based interventions as safe and efficacious treatments for patients with COPD.

Cell-based Therapy for Chronic Obstructive Pulmonary Disease. Rebuilding the Lung

As the prevalence and impact of lung diseases continue to increase worldwide, new therapeutic strategies are desperately needed. Advances in lung-regenerative medicine, a broad field encompassing stem cells, cell-based therapies, and a range of bioengineering approaches, offer new insights into and new techniques for studying lung physiology and pathophysiology. This provides a platform for the development of novel therapeutic approaches. Applicability to chronic obstructive pulmonary disease of recent advances and applications in cell-based therapies, predominantly those with mesenchymal stromal cell-based approaches, and bioengineering approaches for lung diseases are reviewed.

Circulating mesenchymal stem cells in sulfur mustard-exposed patients with long-term pulmonary complications

Sulfur mustard (SM) is a toxic agent that causes acute and long-term pulmonary complications. Recent evidence has shown the impact of SM on mesenchymal stem cells (MSCs). These cells have a critical role in repairing the damaged tissues. In this study, we evaluated the mobilization of MSCs in SM-exposed patients with long-term pulmonary complications. Fifty-nine SM-injured patients with prolonged pulmonary complications and 20 healthy individuals were included. Patients were classified based on taking drugs, having comorbidities, and severity of respiratory consequence. MSCs with phenotype of CD45-CD44⁺CD29⁺CD105⁺ were evaluated in peripheral blood using flow cytometry. Circulating MSCs were lower in SM-exposed patients compared to the control group (0.93 vs. 2.72 respectively, P = 0.005). No significant difference was observed in the MSC count between patients taking corticosteroids or antibiotics and those patients not taking them. Comorbidities like liver and kidney diseases had changed the count of MSCs in SM-exposed subjects. In addition, the frequency of MSCs did not show any association with the severity of long-term pulmonary complications. In conclusion, SM-exposure causes a decline in the frequency of circulating MSCs in survivors. The lower number of the peripheral MSC population in SM-exposed patients was not affected by taking corticosteroids or antibiotics, but comorbidities are probably involved in MSC frequency. The decreases observed in the number of circulating MSCs was not associated with the severity of the pulmonary complications; however, further studies in mustard lung models are required to demonstrate the therapeutic or pathologic role of MSCs in SM injuries.

Mesenchymal Stem Cell-Based Therapy of Inflammatory Lung Diseases: Current Understanding and Future Perspectives

During acute or chronic lung injury, inappropriate immune response and/or aberrant repair process causes irreversible damage in lung tissue and most usually results in the development of fibrosis followed by decline in lung function. Inhaled corticosteroids and other anti-inflammatory drugs are very effective in patients with inflammatory lung disorders, but their long-term use is associated with severe side effects. Accordingly, new therapeutic agents that will attenuate ongoing inflammation and, at the same time, promote regeneration of injured alveolar epithelial cells are urgently needed. Mesenchymal stem cells (MSCs) are able to modulate proliferation, activation, and effector function of all immune cells that play an important role in the pathogenesis of acute and chronic inflammatory lung diseases. In addition to the suppression of lung-infiltrated immune cells, MSCs have potential to differentiate into alveolar epithelial cells in vitro and, accordingly, represent new players in cell-based therapy of inflammatory lung disorders. In this review article, we described molecular mechanisms involved in MSC-based therapy of acute and chronic pulmonary diseases and emphasized current knowledge and future perspectives related to the therapeutic application of MSCs in patients suffering from acute respiratory distress syndrome, pneumonia, asthma, chronic obstructive pulmonary diseases, and idiopathic pulmonary fibrosis.

Mesenchymal stromal cells: a novel therapy for the treatment of chronic obstructive pulmonary disease?

COPD is characterised by tissue destruction and inflammation. Given the lack of curative treatments and the progressive nature of the disease, new treatments for COPD are highly relevant. In vitro cell culture and animal studies have demonstrated that mesenchymal stromal cells (MSCs) have the capacity to modify immune responses and to enhance tissue repair. These properties of MSCs provided a rationale to investigate their potential for treatment of a variety of diseases, including COPD. Preclinical models support the hypothesis that MSCs may have clinical efficacy in COPD. However, although clinical trials have demonstrated the safety of MSC treatment, thus far they have not provided evidence for MSC efficacy in the treatment of COPD. In this review, we discuss the rationale for MSC-based cell therapy in COPD, the main findings from in vitro and in vivo preclinical COPD model studies, clinical trials in patients with COPD and directions for further research.

Bone marrow mesenchymal stem cells ameliorate lung injury through anti-inflammatory and antibacterial effect in COPD mice

The anti-inflammatory and antibacterial mechanisms of bone marrow mesenchymal stem cells (MSCs) ameliorating lung injury in chronic obstructive pulmonary disease (COPD) mice induced by cigarette smoke and Haemophilus Parainfluenza (HPi) were studied. The experiment was divided into four groups in vivo: control group, COPD group, COPD+HPi group, and COPD+HPi+MSCs group. The indexes of emphysematous changes, inflammatory reaction and lung injury score, and antibacterial effects were evaluated in all groups. As compared with control group, emphysematous changes were significantly aggravated in COPD group, COPD+HPi group and COPD+HPi+MSCs group (P<0.01), the expression of necrosis factor-kappaB (NF-κB) signal pathway and proinflammatory cytokines in bronchoalveolar lavage fluid (BALF) were increased (P<0.01), and the phagocytic activity of alveolar macrophages was downregulated (P<0.01). As compared with COPD group, lung injury score, inflammatory cells and proinflammatory cytokines were significantly increased in the BALF of COPD+HPi group and COPD+HPi+MSCs group (P<0.01). As compared with COPD+HPi group, the expression of tumor necrosis factor-α stimulated protein/gene 6 (TSG-6) was increased, the NF-κB signal pathway was depressed, proinflammatory cytokine was significantly reduced, the anti-inflammatory cytokine IL-10 was increased, and lung injury score was significantly reduced in COPD+HPi+MSCs group. Meanwhile, the phagocytic activity of alveolar macrophages was significantly enhanced and bacterial counts in the lung were decreased. The results indicated cigarette smoke caused emphysematous changes in mice and the phagocytic activity of alveolar macrophages was decreased. The lung injury of acute exacerbation of COPD mice induced by cigarette smoke and HPi was alleviated through MSCs transplantation, which may be attributed to the fact that MSCs could promote macrophages into anti-inflammatory phenotype through secreting TSG-6, inhibit NF-кB signaling pathway, and reduce inflammatory response through reducing proinflammatory cytokines and promoting the expression of the anti-inflammatory cytokine. Simultaneously, MSCs could enhance phagocytic activity of macrophages and bacterial clearance. Meanwhile, we detected anti-inflammatory and antibacterial activity of macrophages regulated by MSCs in vitro. As compared with RAW264.7+HPi+CSE group, the expression of NF-кB p65, IL-1β, IL-6 and TNF-α was significantly reduced, and the phagocytic activity of macrophages was significantly increased in RAW264.7+HPi+CSE+MSCs group (P<0.01). The result indicated the macrophages co-cultured with MSCs may inhibit NF-кB signaling pathway and promote phagocytosis by paracrine mechanism.