Mesenchymal stem cells in combination with erythropoietin repair hyperoxia-induced alveoli dysplasia injury in neonatal mice via inhibition of TGF-β1 signaling

High-mobility group box-1 peptide ameliorates bronchopulmonary dysplasia by suppressing inflammation and fibrosis in a mouse model

BACKGROUND

This study aimed to examine the effect of the HMGB1 peptide on Bronchopulmonary dysplasia (BPD)-related lung injury in a mouse model.

RESULTS

HMGB1 peptide ameliorates lung injury by suppressing the release of inflammatory cytokines and decreasing soluble collagen levels in the lungs. Single-cell RNA sequencing showed that the peptide suppressed the hyperoxia-induced inflammatory signature in macrophages and the fibrotic signature in fibroblasts. These changes in the transcriptome were confirmed using protein assays.

CONCLUSION

Systemic administration of HMGB1 peptide exerts anti-inflammatory and anti-fibrotic effects in a mouse model of BPD. This study provides a foundation for the development of new and effective therapies for BPD.

Complex roles of TGF-β signaling pathways in lung development and bronchopulmonary dysplasia

As survival of extremely preterm infants continues to improve, there is also an associated increase in bronchopulmonary dysplasia (BPD), one of the most significant complications of preterm birth. BPD development is multifactorial resulting from exposure to multiple antenatal and postnatal stressors. BPD has both short-term health implications and long-term sequelae including increased respiratory, cardiovascular, and neurological morbidity. Transforming growth factor β (TGF-β) is an important signaling pathway in lung development, organ injury, and fibrosis and is implicated in the development of BPD. This review provides a detailed account on the role of TGF-β in antenatal and postnatal lung development, the effect of known risk factors for BPD on the TGF-β signaling pathway, and how medications currently in use or under development, for the prevention or treatment of BPD, affect TGF-β signaling.

Erythropoietin for preventing bronchopulmonary dysplasia in preterm infants: A systematic review and meta-analysis

BACKGROUND

Recombinant erythropoietin (rEPO) has erythropoiesis and anti-inflammatory properties that might help reduce lung injury in preterm infants.

OBJECTIVE

To conduct a systematic review and meta-analysis to evaluate the possible role of rEPO in altering the risk of bronchopulmonary dysplasia (BPD).

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library databases were searched to identify randomized controlled trials (RCTs) that evaluated the effects of rEPO for the prevention of BPD in preterm infants.

RESULTS

Fourteen studies (3199 infants) were included. Our results could not demonstrate a significant effect of rEPO on the incidence of BPD36 (risk ratio [RR]: 0.97, 95% confidence interval [CI]: 0.87-1.09, p = 0.63, I²  = 0, 12 RCTs, high-quality evidence), BPD28 (RR: 1.28, 95% CI: 0.91-1.79, p = 0.15, I²  = 17%, three RCTs, low-quality evidence) and oxygen dependence days. The test for subgroup analysis by administration route of rEPO showed similar outcomes above. Some of the included trials reported a significant effect of intravenous rEPO on reduction of sepsis (RR: 0.82, 95% CI: 0.70-0.96, p = 0.01, I²  = 0, high-quality evidence) and any stage necrotizing enterocolitis (NEC) (RR: 0.75, 95% CI: 0.59-0.94, p = 0.01, I²  = 0, moderate-quality evidence). The incidence of mortality and stage II or higher NEC was comparable in rEPO and control infants.

CONCLUSION

Our results suggest that rEPO does not affect the risk of developing BPD in preterm infants. Adequately powered RCTs are required to further confirm these findings.

Pharmacotherapy in Bronchopulmonary Dysplasia: What Is the Evidence?

Bronchopulmonary Dysplasia (BPD) is a multifactorial disease affecting over 35% of extremely preterm infants born each year. Despite the advances made in understanding the pathogenesis of this disease over the last five decades, BPD remains one of the major causes of morbidity and mortality in this population, and the incidence of the disease increases with decreasing gestational age. As inflammation is one of the key drivers in the pathogenesis, it has been targeted by majority of pharmacological and non-pharmacological methods to prevent BPD. Most extremely premature infants receive a myriad of medications during their stay in the neonatal intensive care unit in an effort to prevent or manage BPD, with corticosteroids, caffeine, and diuretics being the most commonly used medications. However, there is no consensus regarding their use and benefits in this population. This review summarizes the available literature regarding these medications and aims to provide neonatologists and neonatal providers with evidence-based recommendations.

Patho-mechanisms of the origins of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) continues to be one of the most common complications of prematurity, despite significant advancement in neonatology over the last couple of decades. The new BPD is characterized histopathologically by impaired lung alveolarization and dysregulated vascularization. With the increased survival of extremely preterm infants, the risk for the development of BPD remains high, emphasizing the continued need to understand the patho-mechanisms that play a role in the development of this disease. This brief review summarizes recent advances in our understanding of the maldevelopment of the premature lung, highlighting recent research in pathways of oxidative stress-related lung injury, the role of placental insufficiency, growth factor signaling, the extracellular matrix, and microRNAs.

Lung and Eye Disease Develop Concurrently in Supplemental Oxygen-Exposed Neonatal Mice

Bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) are two debilitating disorders that develop in preterm infants exposed to supplemental oxygen to prevent respiratory failure. Both can lead to lifelong disabilities, such as chronic obstructive pulmonary disease and vision loss. Due to the lack of a standard experimental model of coincident disease, the underlying associations between BPD and ROP are not well characterized. To address this gap, we used the robust mouse model of oxygen-induced retinopathy exposing C57BL/6 mice to 75% oxygen from postnatal day 7 to 12. The cardinal features of ROP were replicated by this strategy, and the lungs of the same mice were simultaneously examined for evidence of BPD-like lung injury, investigating both the short- and long-term effects of early-life supplemental oxygen exposure. At postnatal days 12 and 18, mild lung disease was evident by histopathologic analysis together with the expected vasculopathy in the inner retina. At later time points, the lung lesion had progressed to severe airspace enlargement and alveolar simplification, with concurrent thinning in the outer layer of the retina. In addition, critical angiogenic oxidative stress and inflammatory factors reported to be dysregulated in ROP were similarly impaired in the lungs. These data shed new light on the interconnectedness of these two neonatal disorders, holding potential for the discovery of novel targets to treat BPD and ROP.

Stem cell therapy for preventing neonatal diseases in the 21st century: Current understanding and challenges

Diseases of the preterm newborn such as bronchopulmonary dysplasia, necrotizing enterocolitis, cerebral palsy, and hypoxic-ischemic encephalopathy continue to be major causes of infant mortality and long-term morbidity. Effective therapies for the prevention or treatment for these conditions are still lacking as recent clinical trials have shown modest or no benefit. Stem cell therapy is rapidly emerging as a novel therapeutic tool for several neonatal diseases with encouraging pre-clinical results that hold promise for clinical translation. However, there are a number of unanswered questions and facets to the development of stem cell therapy as a clinical intervention. There is much work to be done to fully elucidate the mechanisms by which stem cell therapy is effective (e.g., anti-inflammatory versus pro-angiogenic), identifying important paracrine mediators, and determining the timing and type of therapy (e.g., cellular versus secretomes), as well as patient characteristics that are ideal. Importantly, the interaction between stem cell therapy and current, standard-of-care interventions is nearly completely unknown. In this review, we will focus predominantly on the use of mesenchymal stromal cells for neonatal diseases, highlighting the promises and challenges in clinical translation towards preventing neonatal diseases in the 21st century.

Are all stem cells equal? Systematic review, evidence map, and meta-analyses of preclinical stem cell-based therapies for bronchopulmonary dysplasia

Regenerative stem cell‐based therapies for bronchopulmonary dysplasia (BPD), the most common preterm birth complication, demonstrate promise in animals. Failure to objectively appraise available preclinical data and identify knowledge gaps could jeopardize clinical translation. We performed a systematic review and network meta‐analysis (NMA) of preclinical studies testing cell‐based therapies in experimental neonatal lung injury. Fifty‐three studies assessing 15 different cell‐based therapies were identified: 35 studied the effects of mesenchymal stromal cells (MSCs) almost exclusively in hyperoxic rodent models of BPD. Exploratory NMAs, for select outcomes, suggest that MSCs are the most effective therapy. Although a broad range of promising cell‐based therapies has been assessed, few head‐to‐head comparisons and unclear risk of bias exists. Successful clinical translation of cell‐based therapies demands robust preclinical experimental design with appropriately blinded, randomized, and statistically powered studies, based on biological plausibility for a given cell product, in standardized models and endpoints with transparent reporting.

Erythropoietin treatment is associated with a reduction in moderate to severe bronchopulmonary dysplasia in preterm infants. A regional retrospective study

Erythropoietin treatment is associated with a reduction in moderate to severe bronchopulmonary dysplasia in preterm infants. A regional retrospective study.

OBJECTIVE

To determine whether premature infants treated with erythropoietin (Epo) in the neonatal period for anemia had a lower incidence of bronchopulmonary dysplasia (BPD), defined as oxygen need at 36 weeks postmenstrual age, and lower rehospitalization rates in the first year of life than infants not exposed.

METHODS

Retrospective study of a population of infants born at 23 to 32 weeks gestational age, between January 2009 and December 2014, with birthweight ≤1500 g. Patient characteristics, and risk factors for BPD were compared between patients who received erythropoietin, and those not exposed. To examine the association between the outcomes of BPD at 36 weeks PMA, rehospitalization, and erythropoietin treatment, we performed a propensity score (PS) analysis using inverse probability of treatment weighted (IPTW) approach. For comparison, we conducted a logistic regression adjusting for the same covariates used to generate PS using the original population.

RESULTS

The study population included 1821 preterm infants: 928 received Epo and 893 did not. Epo treatment was associated with a reduction in BPD (18.8% versus 25.9%, p < 0.01) at 36 weeks PMA and reduced median length of stay with lowest BPD rate with Epo initiation before 2 weeks of age. There was no difference in rehospitalization rates in the first year of life.

CONCLUSION

Erythropoietin treatment was associated with a reduction in BPD but not in rehospitalization rate in the first year of life.

Direct implantations of erythropoietin and autologous EPCs in critical limb ischemia (CLI) area restored CLI area blood flow and rescued remote AMI-induced LV dysfunction

BACKGROUND

This study tested the hypothesis that intramuscular injections of erythropoietin (EPO) and endothelial progenitor cells (EPC) to critical limb ischemia (CLI; primary treatment site) could also improve heart function in rat after acute myocardial infarction (AMI; remote ischemic organ).

METHOD

Adult-male SD rats (n = 40) were equally categorized into group 1 (sham-operated control), group 2 (CLI-AMI), group 3 [CLI-AMI + EPO (10 mg/kg)], group 4 [CLI-AMI + EPCs (1.2 × 10⁶)] and group 5 (CLI-AMI + EPCs + EPO).

RESULTS

By day 21 (end of study period), 2-D echo and Laser doppler showed that left-ventricular injection fraction (LVEF) and the ratio of ischemic to normal blood flow were highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but not different in the latter two groups (all p < 0.0001). Flow cytometry and ELISA demonstrated that circulating angiogenesis factors were significantly progressively increased from groups 1 to 5 (all p < 0.001). The number of small vessels and protein (CD31/eNOS)/cellular (vWF) expressions reflecting integrity of endothelium exhibited an identical pattern to LVEF whereas protein (VEGF/SDF-1α)/cellular (VEGF) expressions were significantly progressively increased from groups 1 to 5 in quadriceps and heart tissues (all p < 0.0001). Protein expressions of apoptotic (Bax/caspase-3/PARP)/inflammatory (MMP-9) and microscopic findings of ischemic/fibrotic/collagen-deposition areas and DNA-damage marker (γ-H2AX+) were lowest in group 1 and significantly progressively decreased from groups 2 to 5 in quadriceps and heart tissues (all p < 0.0001).

CONCLUSIONS

Direct injection of EPO-EPC into CLI effectively restored blood flow in the CLI area and also preserved remote heart function.

Advances in treating bronchopulmonary dysplasia

Introduction: Bronchopulmonary dysplasia (BPD) is a common long-term adverse complication of very premature delivery. Affected infants can suffer chronic respiratory morbidities including lung function abnormalities and reduced exercise capacity even as young adults. Many studies have investigated possible preventative strategies; however, it is equally important to identify optimum management strategies for infants with evolving or established BPD. Areas covered: Respiratory support modalities and established and novel pharmacological treatments. Expert opinion: Respiratory support modalities including proportional assist ventilation and neurally adjusted ventilatory assist are associated with short term improvements in oxygenation indices. Such modalities need to be investigated in appropriate RCTs. Many pharmacological treatments are routinely used with a limited evidence base, for example diuretics. Stem cell therapies in small case series are associated with promising results. More research is required before it is possible to determine if such therapies should be investigated in large RCTs with long-term outcomes.

Recent advances in the pathogenesis of BPD

Bronchopulmonary dysplasia (BPD) continues to be one of the most common complications of preterm birth and is characterized histopathologically by impaired lung alveolarization. Extremely preterm born infants remain at high risk for the development of BPD, highlighting a pressing need for continued efforts to understand the pathomechanisms at play in affected infants. This brief review summarizes recent progress in our understanding of the how the development of the newborn lung is stunted, highlighting recent reports on roles for growth factor signaling, oxidative stress, inflammation, the extracellular matrix and proteolysis, non-coding RNA, and fibroblast and epithelial cell plasticity. Additionally, some concerns about modeling BPD in experimental animals are reviewed, as are new developments in the in vitro modeling of pathophysiological processes relevant to impaired lung alveolarization in BPD.

Timing of erythropoietin modified mesenchymal stromal cell transplantation for the treatment of experimental bronchopulmonary dysplasia

The aim of this study is to optimize the timing of erythropoietin gene modified mesenchymal stem cells (EPO‐MSCs) transplantation for bronchopulmonary dysplasia (BPD). Three weeks post‐operation, the results indicated that the damage of airway structure and apoptosis were significantly decreased, the proliferation was increased in three EPO‐MSCs transplantation groups as compared with BPD mice. Moreover, the inflammation cytokines were improvement in early EPO‐MSCs injection mice than in BPD mice, but there was no significant difference between late injection and BPD groups. Furthermore, the protein expression ratio of p‐p38/p38MAPK was down‐regulation in early mice but not in late transplantation mice. Our findings suggest that EPO‐MSCs maybe attenuate BPD injury in early than in late administration by inhibiting inflammation response through down‐regulation of the p38MAPK signalling pathway.

Effects of bone marrow mesenchymal stem cells transfected with Ang-1 gene on hyperoxia-induced optic nerve injury in neonatal mice

Optic nerve injury triggered retinal ganglion cell (RGC) death and optic nerve atrophy lead to visual loss. Bone marrow mesenchymal stem cells (BMSCs) are stromal cells, capable of proliferating and differentiating into different types of tissues. This aims of this study is to investigate the role of BMSCs transfected with angiopoietin-1 (Ang-1) in optic nerve injury induced by hyperoxia in a neonatal mice model. Ang-1 overexpression vector was constructed and used to transfect BMSCs. Reverse transcription-quantitative polymerase chain reaction was performed to detect Ang-1 expression in BMSCs. The hyperoxia-induced optic nerve injury model was established. The optic nerves at 6-7 mm posterior to the eyeball were extracted, and were treated with luxol fast blue staining, immunohistochemistry, immunofluorescence, and transmission electron microscopy to examine the effects of Ang-1-modified BMSCs on optic nerve injury induced by hyperoxia. The mice in the Ang-1 + BMSCs and BMSCs groups showed remarkably improved myelin sheaths of nerve fibers compared to the hyperoxia saline group. The positive expression and integrated optic density of Ang-1 in the Ang-1 + BMSCs group were significantly higher compared to the air control, hyperoxia saline and BMSCs groups. The number and diameter of myelinated nerve fibers, the diameter of axons and the thickness of myelin sheath in the air control and Ang-1 + BMSCs groups were higher compared to the hyperoxia saline group. Our study provides evidence supporting that Ang-1-modified BMSCs may have preventive and therapeutic effects on hyperoxia-induced optic nerve injury in neonatal mice.

Decreased ZONAB expression promotes excessive transdifferentiation of alveolar epithelial cells in hyperoxia-induced bronchopulmonary dysplasia

Previous studies by our group have confirmed excessive transdifferentiation of alveolar epithelial cells (AECs) in a hyperoxia‑induced bronchopulmonary dysplasia (BPD) model, but the underlying mechanism have remained elusive. The transcription factor zonula occludens 1‑associated nucleic acid binding protein (ZONAB) has the biological functions of inhibition of epithelial cell differentiation and promotion of epithelial cell proliferation. The aim of the present study was to explore the regulatory effect of ZONAB on the transdifferentiation and proliferation of AECs in a model of hyperoxia‑induced lung injury. Newborn Wistar rats were randomly allocated to a model group (inhalation of 85% O2) or a control group (inhalation of normal air), and ZONAB expression in lung tissues was detected at different time‑points. Type II AECs (AEC II) isolated from normal newborn rats were primarily cultured under an atmosphere of 85 or 21% O2, and ZONAB expression in the cells was examined. The primary cells were further transfected with ZONAB plasmid or small interfering (si)RNA and then exposed to hyperoxia, and the indicators for transdifferentiation and proliferation were measured. The present study indicated that ZONAB expression in AEC II of the BPD rats was significantly decreased from 7 days of exposure to hyperoxia onwards. In the AEC II isolated from normal neonatal rats, ZONAB expression in the model group was also reduced compared with that in the control group. After transfection with the plasmid pCMV6‑ZONAB, the expression of aquaporin 5 (type I alveolar epithelial cell marker) decreased and the expression of surfactant protein C (AEC II marker), proliferating‑cell nuclear antigen and cyclin D1 increased, which was opposite to the effects of ZONAB siRNA. Transfection with pCMV6‑ZONAB also alleviated excessive transdifferentiation and inhibited proliferation of AEC II induced by hyperoxia treatment. These results suggest that ZONAB expression in AEC II decreases under hyperoxia conditions, which promotes transdifferentiation and inhibits proliferation of AECs. This may, at least in part, be the underlying mechanism of lung epithelial injury in the hyperoxia-induced BPD model.

Upregulation of Vascular Endothelial Growth Factor in Amniotic Fluid Stem Cells Enhances Their Potential to Attenuate Lung Injury in a Preterm Rabbit Model of Bronchopulmonary Dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that affects extremely preterm infants and remains - despite improvements in neonatal intensive care - a major cause of neonatal mortality and morbidity. Cell-therapeutic strategies employing mesenchymal stem cells (MSC) have been shown to modulate lung development in BPD models.

OBJECTIVE

Herein, we evaluate the potential of human amniotic fluid (hAF)-SC and hAF-SC with upregulated expression of vascular endothelial growth factor (VEGF) as cell-therapeutic agents for BPD.

METHODS

Preterm rabbit pups were raised in normoxia (21% O2) or hyperoxia (≥95% O2). Hyperoxia-exposed pups randomly received an intraperitoneal injection of fibroblasts, naïve hAF-SC, or hAF-SC-VEGF on postnatal day (PN) 0. On PN7, surviving pups were tested for pulmonary (forced oscillation technique) and vascular (pulmonary artery Doppler ultrasound) function, and lungs were processed for morphometric measurements of parenchymal and vascular structure and inflammation.

RESULTS

Intraperitoneal injection of cells resulted in homing to the lungs. The lungs of hyperoxia-exposed animals displayed parenchymal and vascular structural and functional damage reminiscent of BPD, which was significantly improved after treatment with hAF-SC-VEGF. Treating hyperoxia-exposed animals with naïve AF-SC attenuated only the lung inflammation and the vascular structural defect. Treatment with fibroblasts, which were used as a cellular control, did not lead to any improvements.

CONCLUSION

hAF-SC with upregulated VEGF expression display enhanced potential to prevent/reverse lung injury in preterm rabbits, whereas naïve hAF-SC only show a moderate therapeutic potential. These results point towards an added value of VEGF delivered by hAF-SC in the treatment of BPD.

Spatial and temporal expression of SP-B and TGF-β1 in hyperoxia-induced neonatal rat lung injury

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a severe complication of extreme prematurity that can be caused by hyperoxia inhalation. SP-B and TGF-β have been reported to be implicated in the development of lung. This study aimed to reveal the spatial and temporal expression patterns of these two factors in an animal model of BPD.

METHODS

Newborn Sprague-Dawley (SD) rats were subjected to hyperoxia conditions to establish an animal model of BPD. The levels of SP-B, TGF-β, MDA and TAOC, as well as the activations of MAPK and PI3K/AKT pathways in lung tissues were monitored during newborn rats prolonged exposure to hyperoxia.

RESULTS

We found that hyperoxia exposure significantly induced body weight loss of SD rats. H&E staining for morphometric analyses revealed that hyperoxia arrested alveolar development or loss of alveoli, with fewer and dysmorphic capillaries. mRNA and protein levels of SP-B and TGF-β were high expressed in hyperoxic lung tissues. The concentrations of SP-B and TGF-β in bronchoalveolar lavage fluid were also increased. All these increases begin at the 3th day of hyperoxia exposure. MDA content was increased while TAOC content was decreased in response to hyperoxia. Furthermore, hyperoxia activated p38, and deactivated PI3K and AKT expression.

CONCLUSION

Our research demonstrated that SP-B and TGF-β1 were highly expressed in three levels: mRNA and protein levels in lung tissues, and the release of SP-B and TGF-β1 in bronchoalveolar lavage fluid, beginning at the 3th day of hyperoxia exposure.

Recent advances in our understanding of the mechanisms of late lung development and bronchopulmonary dysplasia

The objective of lung development is to generate an organ of gas exchange that provides both a thin gas diffusion barrier and a large gas diffusion surface area, which concomitantly generates a steep gas diffusion concentration gradient. As such, the lung is perfectly structured to undertake the function of gas exchange: a large number of small alveoli provide extensive surface area within the limited volume of the lung, and a delicate alveolo-capillary barrier brings circulating blood into close proximity to the inspired air. Efficient movement of inspired air and circulating blood through the conducting airways and conducting vessels, respectively, generates steep oxygen and carbon dioxide concentration gradients across the alveolo-capillary barrier, providing ideal conditions for effective diffusion of both gases during breathing. The development of the gas exchange apparatus of the lung occurs during the second phase of lung development-namely, late lung development-which includes the canalicular, saccular, and alveolar stages of lung development. It is during these stages of lung development that preterm-born infants are delivered, when the lung is not yet competent for effective gas exchange. These infants may develop bronchopulmonary dysplasia (BPD), a syndrome complicated by disturbances to the development of the alveoli and the pulmonary vasculature. It is the objective of this review to update the reader about recent developments that further our understanding of the mechanisms of lung alveolarization and vascularization and the pathogenesis of BPD and other neonatal lung diseases that feature lung hypoplasia.

EPO modified MSCs can inhibit asthmatic airway remodeling in an animal model

There was no effective measures can be obtained at present to reverse or prevent airway remodeling. We investigated the therapeutic effect of Erythropoietin (EPO) gene modified mesenchymal stem cells (MSCs) on asthmatic airway remodeling and the possible underlied molecular mechanisms. EPO gene was transfected into MSCs via lentivirus vector. The transfected cells (EPO-MSCs) were identified by flow cytometry and the EPO secreting function was detected by PCR and Western blot. MSCs or EPO-MSCs were administrated to albumin (OVA)-induced chronic asthmatic mouse model via tail veins. The asthmatic phenotype was analyzed. Number of cells in bronchoalveolar lavage fluid (BALF) was counted using a hemocytometer. Histological findings of airways were evaluated by microscopic examination. The concentrations of interleukin 4(IL-4), interleukin 5(IL-5), and interleukin 13(IL-13) in lung homogenate were determined by ELISA. The activation state of transforming growth factor-β 1 (TGF-β1), Transforming growth factor beta-activated kinase 1 (TAK1), and p38 Mitogen Activated Protein Kinase (p38MAPK) signaling was detected by Real-Time PCR and Western blotting. EPO-MSCs were successfully constructed. EPO-MSCs showed a more potently suppressive effect on local asthmatic airway inflammation and the level of IL-4, IL-5, and IL-13 in lung tissue than MSCs. Moreover, the numbers of goblet cells, the thicknesses of smooth muscle layer, collagen density, percentage of proliferating cell nuclear antigen positive (PCNA⁺ ) mesenchymal cells, and von Willebrand factor positive(vWF⁺ ) vessels were also significantly inhibited by EPO-MSCs. Furthermore, EPO-MSCs could downregulate the expression of TGF-β1, TAK1, and p38MAPK in lung tissue both in mRNA level and in protein level. EPO gene modified MSCs may more efficiently attenuate asthmatic airway remodeling, which maybe related with the downregulation of TGF-β1-TAK1-p38MAPK pathway activity.

Preclinical evaluation of cell-based strategies to prevent or treat bronchopulmonary dysplasia in animal models: a systematic review

Bronchopulmonary dysplasia (BPD) remains the most common complication of extreme prematurity as no effective treatment is available to date. This calls for the exploration of new therapeutic options like cell therapy, which is already effective for various human (lung) disorders. We systematically searched the MEDLINE, Embase, and Web of Science databases from the earliest date till January 2017 and included original studies on the perinatal use of cell-based therapies (i.e. cells and/or cell-derivatives) to treat BDP in animal models. Fourth publications describing 47 interventions were retrieved. Newborn mice/rats raised in a hyperoxic environment were studied in most interventions. Different cell types - either intact cells or their conditioned medium - were administered, but bone marrow and umbilical cord blood derived mesenchymal stem cells were most prevalent. All studies reported positive effects on outcome parameters including alveolar and vascular morphometry, lung function, and inflammation. Cell homing to the lungs was demonstrated in some studies, but the therapeutic effects seemed to be mostly mediated via paracrine modulation of inflammation, fibrosis and angiogenesis.

CONCLUSION

Multiple rat/mouse studies show promise for cell therapy for BPD. Yet careful study of action mechanisms and side effects in large animal models is imperative before clinical translation can be achieved.