Two-Year Follow-Up Outcomes of Premature Infants Enrolled in the Phase I Trial of Mesenchymal Stem Cells Transplantation for Bronchopulmonary Dysplasia

Late Rescue Therapy with Cord-Derived Mesenchymal Stromal Cells for Established Lung Injury in Experimental Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD), the main complication of extreme prematurity, has lifelong consequences for lung health. Mesenchymal stromal cells (MSCs) prevent lung injury in experimental BPD in newborn rodents when given in the immediate neonatal period. Whether MSC therapy can restore normal lung growth after established lung injury in adulthood is clinically relevant, but currently unknown. Experimental BPD was achieved by exposing newborn rats to 95% O₂ from postnatal days 4-14. Human umbilical cord-derived MSCs were intratracheally administered to rats (1 × 10⁶cells/kg body weight) as a single dose at 3 or 6 months of age followed by assessment at 5 or 8 months of age, respectively. Lung alveolar structure and vessel density were histologically analyzed. O₂-exposed rats exhibited persistent lung injury characterized by arrested alveolar growth with airspace enlargement and a lower vessel density at both 5 and 8 months of age compared with controls. Single-dose MSC treatment at 3 months partially attenuated O₂-induced alveolar injury and restored vessel density at 5 months. Treatment with a single dose at 6 months did not attenuate alveolar injury or vessel density at 8 months. However, treatment with multiple MSC doses at 6, 6.5, 7, and 7.5 months significantly attenuated alveolar injury and improved vessel density at 8 months of age. Treatment of the adult BPD lung with MSCs has the potential to improve lung injury if administered in multiple doses or at an early stage of adulthood.

Congenital diaphragmatic hernia as a potential target for transamniotic stem cell therapy

PURPOSE

We sought to determine whether TRASCET could impact congenital diaphragmatic hernia (CDH).

METHODS

Twelve pregnant dams received Nitrofen on gestational day 9.5 (E9; term = 22 days) to induce fetal CDH. Fetuses were divided into three groups: untreated (n = 31) and two groups receiving volume-matched intraamniotic injections of either saline (n = 37) or a suspension of 2 × 10⁶ cells/mL of amniotic fluid-derived mesenchymal stem cells (afMSCs; n = 65) on E17. Animals were euthanized at term. Expression of fibroblast growth factor-10 (FGF-10), vascular endothelial growth factor-A (VEGF-A), and surfactant protein-C (SPC) was quantified by qRT-PCR. Statistical analysis was by the Mann-Whitney U test with Bonferroni adjusted criterion (p ≤ 0.01).

RESULTS

Among survivors with CDH (n = 27/133), the TRASCET group showed significant downregulation of FGF-10 and VEGF-A gene expressions compared to the untreated (p < 0.001 for both) and saline groups (p = 0.005 and p = 0.004, respectively). SPC expression was higher in the TRASCET group compared to the untreated group (p = 0.01), but not the saline group (p = 0.043). Lung laterality had minimal impact on these comparisons.

CONCLUSIONS

Transamniotic stem cell therapy affects select processes of lung development in experimental congenital diaphragmatic hernia. Further scrutiny into this novel therapy as a potential component of the prenatal management of this disease is warranted.

LEVEL OF EVIDENCE

N/A (animal and laboratory study).

Allogeneic human umbilical cord-derived mesenchymal stem cells for severe bronchopulmonary dysplasia in children: study protocol for a randomized controlled trial (MSC-BPD trial)

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a complex lung pathological lesion secondary to multiple factors and one of the most common chronic lung diseases. It has a poor prognosis, especially in preterm infants. However, effective therapies for this disease are lacking. Stem-cell therapy is a promising way to improve lung injury and abnormal alveolarization, and the human umbilical cord (hUC) is a good source of mesenchymal stem cells (MSCs), which have demonstrated efficacy in other diseases. We hypothesized that intravenously administered allogeneic hUC-MSCs are safe and effective for severe BPD.

METHODS

The MSC-BPD trial is a randomized, single-center, open-label, dose-escalation, phase-II trial designed to investigate the safety and efficacy of hUC-MSCs in children with severe BPD. In this study, 72 patients will be enrolled and randomly divided into two intervention groups and one control group. Patients in the intervention groups will receive a low dose of hUC-MSCs (n = 24; 2.5 million cells/kg) or a high dose of hUC-MSCs (n = 24; 5 million cells/kg) in combination with traditional supportive treatments for BPD. The patients in the control group (n = 24) will be treated with traditional supportive treatments alone without hUC-MSCs. The primary outcome measures will be cumulative duration of oxygen therapy. Follow-up assessments will be performed at 1, 3, 6, 12, and 24 months post intervention, and the key outcome during follow-up will be changes on chest radiography. Statistical analyses will evaluate the efficacy of the hUC-MSC treatment.

DISCUSSION

This will be the first randomized controlled trial to evaluate the safety and efficacy of intravenously administered hUC-MSCs in children with severe BPD. Its results should provide a new evidence-based therapy for severe BPD.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03601416. Registered on 26 July 2018.

Soluble PTX3 of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Attenuates Hyperoxic Lung Injury by Activating Macrophage Polarization in Neonatal Rat Model

Therapeutic treatment of various inflammation-related diseases using mesenchymal stem cells (MSCs) has increased in recent years because of the paracrine action of these cells but shows several limitations. First, MSC-based therapies exhibit varying efficacies; thus, biomarkers should be determined to identify who may benefit from these candidate therapeutic agents. Second, the mechanism underlying the therapeutic effects is poorly understood. To evaluate the effects of human umbilical cord blood-derived MSCs (UCB-MSCs) on macrophages, the macrophage cell line NR8383 stimulated with lipopolysaccharide (LPS) was cocultured by UCB-MSCs. We found that UCB-MSCs mediated changes in macrophage polarization towards M2 from M1 macrophages. To identify the paracrine action underlying the anti-inflammation effect of UCB-MSCs, the secretion of UCB-MSCs exposed to LPS-stimulated NR8383 cells was tested using a biotin label-based 507 antibody array. Among the secreted proteins, we selected pentraxin-related protein PTX3/tumor necrosis factor-inducible gene 14 protein (PTX3) to investigate its association with UCB-MSCs in macrophage polarization. We found that human PTX3 was secreted from UCB-MSCs under inflammation condition and reinforced the M2 macrophage marker via the Dectin-1 receptor by activating MSK1/2 phosphorylation signaling in NR8383 cells. Accordingly, knockdown of PTX3 in UCB-MSCs significantly attenuated their therapeutic effects in a neonatal hyperoxic lung injury resulting in reduced survival, lung alveolarization, M2 marker expression, Dectin-1 levels, anti-inflammatory cytokines, and improved M1 marker expression and inflammatory cytokines compared to control MSC-injected rats. UCB-MSCs show therapeutic potential by controlling macrophage polarization. Interestingly, higher PTX3 levels in UCB-MSCs induced greater improvement in the therapeutic effects than lower PTX3 levels. Collectively, PTX3 is a potential marker with critical paracrine effects for predicting the therapeutic potential of MSC therapy in inflammatory diseases; quality control assessments using PTX3 may be useful for improving the therapeutic effects of UCB-MSCs.

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.

The Potential of Mesenchymal Stromal Cell as Therapy in Neonatal Diseases

Mesenchymal stromal cells (MSCs) can be derived from various tissue sources, such as the bone marrow (BMSCs), adipose tissue (ADSCs), umbilical cord (UC-MSCs) and umbilical cord blood (UCB-MSCs). Clinical trials have been conducted to investigate the potential of MSCs in ameliorating neonatal diseases, including bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC). In preclinical studies, MSC therapy has been tested for the treatment of various neonatal diseases affecting the heart, eye, gut, and brain as well as sepsis. Up to date, the number of clinical trials using MSCs to treat neonatal diseases is still limited. The data reported thus far positioned MSC therapy as safe with positive outcomes. However, most of these trials are still preliminary and generally smaller in scale. Larger trials with more appropriate controls and a longer follow-up period need to be conducted to prove the safety and efficacy of the therapy more conclusively. This review discusses the current application of MSCs in treating neonatal diseases, its mechanism of action and future direction of this novel therapy, including the potential of using MSC-derived extracellular vesicles instead of the cells to treat various clinical conditions in the newborn.

Neuroprotection Strategies in Preterm Encephalopathy

Advances in neonatology have led to unprecedented improvements in neonatal survival such that those born as early as 22 weeks of gestation now have some chance of survival, and over 70% of those born at 24 weeks of gestation survive. Up to 50% of infants born extremely preterm develop poor outcomes involving long-term neurodevelopmental impairments affecting cognition and learning, or motor problems such as cerebral palsy. Poor outcomes arise because the preterm brain is vulnerable both to direct injury (by events such as intracerebral hemorrhage, infection, and/or hypoxia), or indirect injury due to disruption of normal development. This neonatal brain injury and/or dysmaturation is called "encephalopathy of prematurity". Current and future strategies to improve outcomes in this population include prevention of preterm birth, and pre-, peri-, and postnatal approaches to protect the developing brain. This review will describe mechanisms of preterm brain injury, and current and upcoming therapies in the antepartum and postnatal period to improve preterm encephalopathy.

Two-year outcomes of infants enrolled in the first-in-human study of amnion cells for bronchopulmonary dysplasia

We previously reported on the immediate safety and neonatal outcomes of six premature infants with severe bronchopulmonary dysplasia (BPD) who were administered human amnion epithelial cells (hAECs). One infant died in the neonatal period due to unrelated causes. In this study, we aimed to assess the long‐term safety and follow‐up outcomes of the five surviving infants until 2 years corrected age (CA). hAECs were administered intravenously at a dose of 1 × 10⁶ cells per kilogram after 36 weeks postconceptional age in infants with established BPD. Study follow‐up consisted of assessment of any adverse events, growth, and respiratory, cardiac, and neurodevelopmental outcomes over four time points (6, 12, 18, and 24 months CA). Investigations included chest x‐rays, cranial and abdominal ultrasounds, and echocardiograms at regular intervals as well as a magnetic resonance imaging (MRI) brain at 2 years CA. All five infants were alive at 2 years CA. Median time to wean off oxygen was 24 (10‐36) months. Two infants had pulmonary hypertension, which resolved by 2 years of age. Four infants were rehospitalized briefly for viral or bacterial infections during the 2 years. MRI brain findings included normal (n = 1), and mild to moderate white matter loss (n = 2). Neurodisabilities diagnosed included hemiplegic cerebral palsy (n = 1), global developmental delay (n = 3), and severe hearing loss (n = 3). No evidence of tumor formation was noted on physical examinations or on any imaging. There were no long‐term adverse events observed that could be attributed to hAEC administration. We observed long‐term effects of extreme prematurity and severe BPD in the cohort.

Autologous cord blood cell infusion in preterm neonates safely reduces respiratory support duration and potentially preterm complications

Preterm birth and its complications are the leading cause of neonatal death. The main underlying pathological mechanisms for preterm complications are disruption of the normal maturation processes within the target tissues, interrupted by premature birth. Cord blood, as a new and convenient source of stem cells, may provide new, promising options for preventing preterm complications. This prospective, nonrandomized placebo controlled study aimed at investigating the effect of autologous cord blood mononuclear cells (ACBMNC) for preventing preterm associated complications. Preterm infants less than 35 weeks gestational age were assigned to receive ACBMNC (5 × 10⁷ cells/kg) intravenous or normal saline within 8 hours after birth. Preterm complication rates were compared between two groups to demonstrate the effect of ACBMNC infusion in reducing preterm complications. Fifteen preterm infants received ACBMNC infusion, and 16 infants were assigned to the control group. There were no significant differences when comparing mortality and preterm complication rates before discharge. However, ACBMNC infusion demonstrated significant decreases in duration of mechanical ventilation (3.2 days vs 6.41 days, P = .028) and oxygen therapy (5.33 days vs 11.31 days, P = .047). ACBMNC infusion was effective in reducing respiratory support duration in very preterm infants. Due to the limited number of patients enrolled, powered randomized controlled trials are needed to better define its efficacy.

Mesenchymal stem cells for the prevention of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease in preterm infants who have been treated with supplemental oxygen and mechanical ventilation. Despite major advances in perinatal and neonatal medicine, limited progress has been made in reducing BPD rates. The use of mesenchymal stem cells (MSC) is a promising and innovative therapy for several diseases because they are easy to extract and they have low immunogenicity, anti-inflammatory properties, and regenerative ability. According to several pre-clinical studies that have used BPD animal models, one mechanism of action for MSC in BPD is mainly due to the paracrine effects of MSC-derived humoral factors, such as interleukin (IL)-6, IL-8, vascular endothelial growth factor, collagen, and elastin, rather than the multilineage and regenerative capacities of MSC. Cell-free preparations derived from MSC, including conditioned media and exosomes, remain a pre-clinical technology despite their great clinical potential. A first-in-human clinical trial of MSC treatment for BPD was performed as a phase I dose-escalation trial using umbilical cord blood-derived MSC. That trial demonstrated the short- and long-term safety and feasibility of MSC, given that significantly reduced inflammatory marker expression was observed in tracheal aspirates. As of recently, several clinical trials of MSC use for BPD are ongoing or are planned in some countries to investigate the efficacy of MSC in the prevention or treatment of BPD in premature infants. Many clinicians are currently awaiting the results from these trials so that MSC can be used clinically for human BPD.

Decorin Secreted by Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Induces Macrophage Polarization via CD44 to Repair Hyperoxic Lung Injury

Bronchopulmonary dysplasia (BPD), caused by hyperoxia in newborns and infants, results in lung damage and abnormal pulmonary function. However, the current treatments for BPD are steroidal and pharmacological therapies, which cause neurodevelopmental impairment. Treatment with umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) is an efficient alternative approach. To prevent pulmonary inflammation in BPD, this study investigated the hypothesis that a key regulator was secreted by MSCs to polarize inflammatory macrophages into anti-inflammatory macrophages at inflammation sites. Lipopolysaccharide-induced macrophages co-cultured with MSCs secreted low levels of the inflammatory cytokines, IL-8 and IL-6, but high levels of the anti-inflammatory cytokine, IL-10. Silencing decorin in MSCs suppressed the expression of CD44, which mediates anti-inflammatory activity in macrophages. The effects of MSCs were examined in a rat model of hyperoxic lung damage. Macrophage polarization differed depending on the levels of decorin secreted by MSCs. Moreover, intratracheal injection of decorin-silenced MSCs or MSCs secreting low levels of decorin confirmed impaired alveolarization of damaged lung tissues by down-regulation of decorin. In tissues, a decrease in the anti-inflammatory macrophage marker, CD163, was observed via CD44. Thus, we identified decorin as a key paracrine factor, inducing macrophage polarization via CD44, a master immunoregulator in mesenchymal stem cells.

Extracellular Vesicles as a Potential Therapy for Neonatal Conditions: State of the Art and Challenges in Clinical Translation

Despite advances in intensive care, several neonatal conditions typically due to prematurity affect vital organs and are associated with high mortality and long-term morbidities. Current treatment strategies for these babies are only partially successful or are effective only in selected patients. Regenerative medicine has been shown to be a promising option for these conditions at an experimental level, but still warrants further exploration for the development of optimal treatment. Although stem cell-based therapy has emerged as a treatment option, studies have shown that it is associated with potential risks and hazards, especially in the fragile population of babies. Recently, extracellular vesicles (EVs) have emerged as an attractive therapeutic alternative that holds great regenerative potential and is cell-free. EVs are nanosized particles endogenously produced by cells that mediate intercellular communication through the transfer of their cargo. Currently, EVs are garnering considerable attention as they are the key effectors of stem cell paracrine signaling and can epigenetically regulate target cell genes through the release of RNA species, such as microRNA. Herein, we review the emerging literature on the therapeutic potential of EVs derived from different sources for the treatment of neonatal conditions that affect the brain, retinas, spine, lungs, and intestines and discuss the challenges for the translation of EVs into clinical practice.

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.

[Mesenchymal stem cell transplantation in the treatment of bronchopulmonary dysplasia: opportunities and challenges]

Bronchopulmonary dysplasia (BPD) is one of the most common chronic lung diseases in neonates especially in preterm infants. It is also the main reason leading to a poor prognosis. The prognosis of the neonates with BPD is unsatisfactory with current treatment strategies. Recent clinical trails have found that mesenchymal stem cell (MSC) transplantation might be effective and promising for treatment of BPD in neonates. This article outlines the characteristics of MSC and the potential mechanisms of MSC transplantation for BPD in vivo, and the safety and feasibility of MSC transplantation in BPD neonates, as well as the challenges in clinical trials on MSC transplantation for treatment of BPD.

Drugs for the Prevention and Treatment of Bronchopulmonary Dysplasia

Rates of bronchopulmonary dysplasia (BPD) are increasing. After preterm birth, there are important developmental periods in which neonates are more vulnerable to stressful events. These periods are opportunities for pharmacologic interventions. Many drugs remain inadequately tested and no new drugs have been approved in more than 25 years for BPD prevention or therapy. More progress is needed in defining appropriate end points based on the pathophysiology of BPD and postdischarge chronic pulmonary insufficiency of prematurity and to develop effective new drugs. In addition, much work is needed to better define perinatal factors, early postnatal findings, and physiologic phenotypes or endotypes.

Cord blood research, banking, and transplantation: achievements, challenges, and perspectives

The first hematopoietic transplant in which umbilical cord blood (UCB) was used as the source of hematopoietic cells was performed in October 1988. Since then, significant achievements have been reported in terms of our understanding of the biology of UCB-derived hematopoietic stem (HSCs) and progenitor (HPCs) cells. Over 40,000 UCB transplants (UCBTs) have been performed, in both children and adults, for the treatment of many different diseases, including hematologic, metabolic, immunologic, neoplastic, and neurologic disorders. In addition, cord blood banking has been developed to the point that around 800,000 units are being stored in public banks and more than 4 million units in private banks worldwide. During these 30 years, research in the UCB field has transformed the hematopoietic transplantation arena. Today, scientific and clinical teams are still working on different ways to improve and expand the use of UCB cells. A major effort has been focused on enhancing engraftment to potentially reduce risk of infection and cost. To that end, we have to understand in detail the molecular mechanisms controlling stem cell self-renewal that may lead to the development of ex vivo systems for HSCs expansion, characterize the mechanisms regulating the homing of HSCs and HPCs, and determine the relative place of UCBTs, as compared to other sources. These challenges will be met by encouraging innovative research on the basic biology of HSCs and HPCs, developing novel clinical trials, and improving UCB banking both in the public and private arenas.

Excessive activation of NMDA receptor inhibits the protective effect of endogenous bone marrow mesenchymal stem cells on promoting alveolarization in bronchopulmonary dysplasia

We studied the role of bone marrow mesenchymal stem cells (MSCs) in our established model of bronchopulmonary dysplasia (BPD) induced by intrauterine hypoxia in the rat. First, we found that intrauterine hypoxia can reduce the number of MSCs in lungs and bone marrow of rat neonates, whereas the administration of granulocyte colony-stimulating factor or busulfan to either motivate or inhibit bone marrow MSCs to lungs altered lung development. Next, in vivo experiments, we confirmed that intrauterine hypoxia also impaired bone marrow MSC proliferation and decreased cell cycling activity. In vitro, by using the cultured bone marrow MSCs, the proliferation and the cell cycling activity of MSCs were also reduced when N-methyl-d-aspartic acid (NMDA) was used as an NMDA receptor (NMDAR) agonist. When MK-801 or memantine as NMDAR antagonists in vitro or in vivo was used, the reduction of cell cycling activity and proliferation were partially reversed. Furthermore, we found that intrauterine hypoxia could enhance the concentration of glutamate, an amino acid that can activate NMDAR, in the bone marrow of neonates. Finally, we confirmed that the increased concentration of TNF-ɑ in the bone marrow of neonatal rats after intrauterine hypoxia induced the release of glutamate and reduced the cell cycling activity of MSCs, and the latter could be partially reversed by MK-801. In summary, intrauterine hypoxia could decrease the number of bone marrow MSCs that could affect lung development and lung function through excessive activation of NMDAR that is partially caused by TNF-ɑ.

Bronchopulmonary Dysplasia: An Update on Experimental Therapeutics

Bronchopulmonary dysplasia (BPD) is a chronic inflammatory lung disease that affects thousands of newborns and infants every year. Although it is accepted that BPD results from lung damage and inflammation triggered by mechanical ventilation and hyperoxia, the causes and molecular events leading to lung damage and arrested development remain unknown. While recent advances in neonatal care have improved the survival of very low-weight infants, the rates of BPD have not improved accordingly. This is mainly due to our limited understanding of the disease’s pathogenesis and the effective therapeutic options available. Current therapeutics for BPD involve ventilation management, steroid treatment, and administration of various agents, such as pulmonary surfactant, caffeine, vitamin A, nitric oxide, and stem cells. However, the efficacy of these agents in preventing and ameliorating BPD symptoms varies depending on the populations studied and the disease stage. As the field moves towards personalised therapeutic approaches, this review summarises clinical and experimental studies conducted in various models, aiming to increase understanding of the cellular and molecular mechanisms by which these agents can prevent or treat BPD. Due to the increasing number of extremely premature infants, it is imperative that we continue to work towards understanding the mechanisms of BPD pathogenesis and generating more effective therapeutic options.

Assessment of iPSC teratogenicity throughout directed differentiation toward an alveolar-like phenotype

Considerable work has gone into creating cell therapies from induced pluripotent stem cells (iPSCs) since their discovery just over a decade ago. However, comparatively little research has been done concerning the safety of iPSCs and their progeny and specifically the mechanisms governing teratogenicity. The aim of this study was to ascertain at what developmental phase iPSCs undergoing differentiation to an alveolar-like phenotype lose their capacity to form a teratoma and uncover potential mechanisms responsible. iPSCs were differentiated using a previously published directed differentiation protocol mirroring alveolar embryogenesis. At each developmental phase cell phenotype was assessed and cells mixed with Matrigel and injected subcutaneously above the hind limbs of NSG mice to determine teratogenicity. A genetic screen of 42 genes commonly associated with teratoma formation was conducted on all the cells and any resulting teratoma. It was found that neither NKX2-1 lung progenitors nor terminally differentiated alveolar-like cells formed teratomas. As expected the expression of pluripotency markers was diminished over differentiation. However, the expression of two proteoglycans, decorin and lumican, was increased more than 3000x during differentiation. Both decorin and lumican are putative tumor suppressors with additional functions in angiogenesis, fibrosis, inflammation and autophagy. We hypothesize that the increasing expression of these proteoglycans by iPSCs as they differentiate may act to inhibit host endothelial cell recruitment when implanted resulting in the inhibition of any teratoma formation by any remaining undifferentiated iPSCs.

Intratracheal administration of clinical-grade mesenchymal stem cell-derived extracellular vesicles reduces lung injury in a rat model of bronchopulmonary dysplasia

Mesenchymal stem cells (MSCs) prevent the onset of bronchopulmonary dysplasia (BPD) in animal models, an effect that seems to be mediated by their secreted extracellular vesicles (EVs). The aim of this study was to compare the protective effects of intratracheally (IT) administered MSCs versus MSC-EVs in a hyperoxia-induced rat model of BPD. At birth, rats were distributed as follows: animals raised in ambient air for 2 wk ( n = 10), and animals exposed to 60% oxygen for 2 wk and treated with IT-administered physiological solution ( n = 10), MSCs ( n = 10), or MSC-EVs ( n = 10) on postnatal days 3, 7, and 10. The sham-treated hyperoxia-exposed animals showed reductions in total surface area of alveolar air spaces, and total number of alveoli ( Nalv), and an increased mean alveolar volume (Valv). EVs prompted a significant increase in Nalv ( P < 0.01) and a significant decrease in Valv ( P < 0.05) compared with sham-treated animals, whereas MSCs only significantly improved Nalv ( P < 0.05). Small pulmonary vessels of the sham-treated hyperoxia-exposed rats also showed an increase in medial thickness, which only EVs succeeded in preventing significantly ( P < 0.05). In conclusion, both EVs and MSCs reduce hyperoxia-induced damage, with EVs obtaining better results in terms of alveolarization and lung vascularization parameters. This suggests that IT-administered EVs could be an effective approach to BPD treatment.

Paving the Road for Mesenchymal Stem Cell-Derived Exosome Therapy in Bronchopulmonary Dysplasia and Pulmonary Hypertension

Bronchopulmonary dysplasia (BPD) is a chronic neonatal lung disease characterized by inflammation and arrest of alveolarization. Its common sequela, pulmonary hypertension (PH), presents with elevated pulmonary vascular resistance associated with remodeling of the pulmonary arterioles. Despite notable advancements in neonatal medicine, there is a severe lack of curative treatments to help manage the progressive nature of these diseases. Numerous studies in preclinical models of BPD and PH have demonstrated that therapies based on mesenchymal stem/stromal cells (MSCs) can resolve pulmonary inflammation and ameliorate the severity of disease. Recent evidence suggests that novel, cell-free approaches based on MSC-derived exosomes (MEx) might represent a compelling therapeutic alternative offering major advantages over treatments based on MSC transplantation. Here, we will discuss the development of MSC-based therapies, stressing the centrality of paracrine action as the actual vector of MSC therapeutic functionality, focusing on MEx. We will briefly present our current understanding of the biogenesis and secretion of MEx, and discuss potential mechanisms by which they afford such beneficial effects, including immunomodulation and restoration of homeostasis in diseased states. We will also review ongoing clinical trials using MSCs as treatment for BPD that pave the way for bringing cell-free, MEx-based therapeutics from the bench to the NICU setting.

Bronchopulmonary Dysplasia: An Update of Current Pharmacologic Therapies and New Approaches

Bronchopulmonary dysplasia (BPD) remains the most prevalent long-term morbidity of surviving extremely preterm infants and is associated with significant health care utilization in infancy and beyond. Recent advances in neonatal care have resulted in improved survival of extremely low birth weight (ELBW) infants; however, the incidence of BPD has not been substantially impacted by novel interventions in this vulnerable population. The multifactorial cause of BPD requires a multi-pronged approach for prevention and treatment. New approaches in assisted ventilation, optimal nutrition, and pharmacologic interventions are currently being evaluated. The focus of this review is the current state of the evidence for pharmacotherapy in BPD. Promising future approaches in need of further study will also be reviewed.

Mesenchymal Stem Cells for Severe Intraventricular Hemorrhage in Preterm Infants: Phase I Dose-Escalation Clinical Trial

We previously demonstrated that transplanting mesenchymal stem cells (MSCs) improved recovery from brain injury induced by severe intraventricular hemorrhage (IVH) in newborn rats. To assess the safety and feasibility of MSCs in preterm infants with severe IVH, we performed a phase I dose-escalation clinical trial. The first three patients received a low dose of MSCs (5 × 106 cells/kg), and the next six received a high dose (1 × 107 cells/kg). We assessed adverse outcomes, including mortality and the progress of posthemorrhagic hydrocephalus. Intraventricular transplantation of MSCs was performed in nine premature infants with mean gestational age of 26.1 ± 0.7 weeks and birth weight of 808 ± 85 g at 11.6 ± 0.9 postnatal days. Treatment with MSCs was well tolerated, and no patients showed serious adverse effects or dose-limiting toxicities attributable to MSC transplantation. There was no mortality in IVH patients receiving MSCs. Infants who underwent shunt surgery showed a higher level of interleukin (IL)-6 in cerebrospinal fluid (CSF) obtained before MSC transplantation in comparison with infants who did not receive a shunt. Levels of IL-6 and tumor necrosis factor-α in initially obtained CSF correlated significantly with baseline ventricular index. Intraventricular transplantation of allogeneic human UCB-derived MSCs into preterm infants with severe IVH is safe and feasible, and warrants a larger, and controlled, phase II study. Stem Cells Translational Medicine 2018;7:847-856.

Stem cell-based therapies in neonatology: a new hope

Despite progress made in neonatal intensive care, complications of extreme preterm birth still contribute as the main cause of death to children below 5 years of age. Stem cell-based therapies-mesenchymal stromal cells in particular-offer a new hope in preventing and/or restoring organ damage in extreme preterm infants. Early phase clinical trials, fueled by promising preclinical studies on lung and brain injury, have begun. While the enthusiasm in the neonatal community is palpable, much more needs to be learnt about cell-based therapies. Maintaining the balance between temptation and a cautious, evidence-based approach will be critical for cell therapies to fulfil their promise in substantially improving the outcome of extreme preterm infants.

Intratracheal transplantation of mesenchymal stem cells attenuates hyperoxia-induced lung injury by down-regulating, but not direct inhibiting formyl peptide receptor 1 in the newborn mice

Formyl peptide receptor 1 (FPR1) has been shown to be a key regulator of inflammation. However, its role in bronchopulmonary dysplasia (BPD) has not been delineated yet. We investigated whether FPR1 plays a pivotal role in regulating lung inflammation and injuries, and whether intratracheally transplanted mesenchymal stem cells (MSCs) attenuate hyperoxic lung inflammation and injuries by down-regulating FPR1. Newborn wild type (WT) or FPR1 knockout (FPR1^-/-) C57/BL6 mice were randomly exposed to 80% oxygen or room air for 14 days. At postnatal day (P) 5, 2×10⁵ MSCs were intratracheally transplanted. At P14, mice were sacrificed for histopathological and morphometric analyses. Hyperoxia significantly increased lung neutrophils, macrophages, and TUNEL-positive cells, while impairing alveolarization and angiogenesis, along with a significant increase in FPR1 mRNA levels in WT mice. The hyperoxia-induced lung inflammation and lung injuries were significantly attenuated, with the reduced mRNA level of FPR1, in WT mice with MSC transplantation and in FPR1^-/- mice, irrespective of MSCs transplantation. However, only MSC transplantation, but not the FPR1 knockout, significantly attenuated the hyperoxia-induced increase in TUNEL-positive cells. Our findings indicate that FPR1 play a critical role in regulating lung inflammation and injuries in BPD, and MSCs attenuate hyperoxic lung inflammation and injuries, but not apoptosis, with down regulating, but not direct inhibiting FPR1.

Off-label mesenchymal stromal cell treatment in two infants with severe bronchopulmonary dysplasia: clinical course and biomarkers profile

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most prevalent sequelae of premature birth, for which therapeutic options are currently limited. Mesenchymal stromal cells (MSCs) are a potential therapy for prevention or reversal of BPD.

SERIES OF CASES

We report on two infants with severe BPD in whom off-label treatment with repeated intravenous doses of allogeneic bone marrow-derived MSCs were administered. We analyzed the temporal profile of serum and tracheal cytokines and growth factors as well as safety, tolerability and clinical response. The administration of repeated intravenous doses of MSCs in two human babies with severe and advanced BPD was feasible and safe and was associated with a decrease of pro-inflammatory molecules and lung injury biomarkers. Both patients were at very advanced stages of BPD with very severe lung fibrosis and did not survive the disease.

CONCLUSIONS

MSCs are a promising therapy for BPD, but they should be administered in early stages of the disease.

Cell-based therapy for bronchopulmonary dysplasia in preterm infants 1

Bronchopulmonary dysplasia (BPD) is the most common complication of extreme prematurity. Currently, there is no specific treatment available. Preclinical studies support cell therapy as a promising therapy for BPD in preterm infants. A successful translation to a safe and effective clinical intervention depends on multiple factors including the perspective of neonatal health care providers. A 2-hour workshop with 40 Canadian neonatologists was held to enhance the design of a phase II trial of stem cells for babies at risk for BPD, with a focus on the population to target and the outcomes to measure in such a trial. The consensus was that infants recruited in an early trial of stem cells should be the ones with the highest risk of developing severe BPD. This risk should be established based on known antenatal, perinatal, and postnatal risk factors. The primary outcome in a phase II trial will be focussed on a non-clinical outcome (e.g., a dose-finding study or a safety study). With other aspects of a translational study discussed, this workshop contributed to accelerate the design of a first Canadian clinical cell-therapy study for BPD in preterm infants.

Review shows that using surfactant a number of times or as a vehicle for budesonide may reduce the risk of bronchopulmonary dysplasia

AIM

Bronchopulmonary dysplasia (BPD) remains the most common respiratory morbidity in immature infants. This review describes the diagnosis of BPD has evolved and summarises the therapeutic approaches that have made it possible to limit the incidence of BPD.

METHOD

We reviewed the literature from the first definition of BPD by Northway in 1967 to the surfactant treatment policies that are currently in use, drawing on more than 50 papers up to 2017.

RESULTS

Our review showed that improvements in neonatal survival have been associated with an increased risk of severe BPD, significant levels of long-term morbidity and the increased use of healthcare resources. These issues have encouraged researchers to explore potential new treatments that limit the incidence of BPD. Repeated surfactant instillation and the use of surfactant as a vehicle for budesonide are promising strategies for alleviating the burden of chronic lung disease. Ongoing research on surfactant or stem cell therapy may further improve the respiratory prognosis for prematurely born children.

CONCLUSION

Considerable research has been carried out into the increase in BPD, which has resulted from improvements in neonatal survival. Key areas of research include repeated surfactant administration, using surfactant as a vehicle for budesonide and stem cell therapy.

Novel therapeutics for bronchopulmonary dysplasia

PURPOSE OF REVIEW

This review provides a concise summary of recent literature pertaining to emerging therapies for bronchopulmonary dysplasia (BPD). To provide context for the presented therapies, a brief overview of recently proposed changes to the definition of BPD and the concept of expanded respiratory outcomes is included.

RECENT FINDINGS

New or redefined respiratory outcomes are required to improve accuracy in evaluating new therapies and correlating results with long-term clinical outcomes of importance. Dexamethasone is no longer the only steroid-based therapy showing promise for impacting BPD. Early trials indicate hydrocortisone, inhaled budesonide, and a budesonide-surfactant combination may be of benefit to preterm infants. Additionally, simple approaches like increasing utilization of mother's own milk may deserve more emphasis. Of significant interest is the traction stem cell therapies are acquiring as one of the more anticipated treatments for BPD. A new preclinical meta-analysis demonstrates the benefits of mesenchymal stromal cell therapy in animal models while the results of early clinical trials remain eagerly awaited.

SUMMARY

BPD continues to be the most frequently occurring significant morbidity for extremely preterm infants, yet highly effective therapies remain elusive. Promising new treatments are on the horizon, but only continued efforts to complete well-designed clinical trials will determine the true impact of these emerging therapies.

Mesenchymal stem cell transplantation as an effective treatment strategy for ischemic stroke in Asia: a meta-analysis of controlled trials

Objective

The aim of this study was to evaluate the efficacy and safety of the mesenchymal stem cell (MSC) therapy in patients with ischemic stroke (IS).

Materials and methods

Clinical trials involved in this research were searched from PubMed, Web of Science, Cochrane Library, Embase, Wanfang and CNKI database. Therapeutic effects of MSC therapy were assessed according to National Institutes of Health Stroke Scale (NIHSS), Barthel index (BI), Fugl-Meyer Assessment (FMA) and Functional Independence Measure (FIM), and its safety was evaluated based on adverse events.

Results

This research covered 23 trials including 1,279 IS patients. Based on our analysis, the overall condition of IS patients significantly improved after MSC therapy, indicated by decreased NIHSS and increased BI, FMA and FIM scores. Our analysis also showed that the treatment effects in the MSC transplantation group were superior to those in the control group (routine medication therapy) with statistical significance for NIHSS (1 month after therapy: odds ratio [OR]=-1.92, CI=-3.49 to -0.34, P=0.02; 3 months after therapy: OR=-2.65, CI=-3.40 to -1.90, P<0.00001), BI (1 month after therapy: OR=0.99, CI=0.19-1.79, P=0.02; 6 months after therapy: OR=10.10, CI=3.07-17.14, P=0.005), FMA (3 months after therapy: OR=10.20, CI=3.70-16.70, P=0.002; 6 months after therapy: OR=10.82, CI=6.45-15.18, P<0.00001) and FIM (1 month after therapy: OR=15.61, CI=-0.02 to 31.24, P=0.05; 6 months after therapy: OR=16.56, CI=9.06-24.06, P<0.0001). No serious adverse events were reported during MSC therapy.

Conclusion

MSC therapy is safe and effective in treating IS by improving the neurological deficits, motor function and daily life quality of patients.

Vascular endothelial growth factor mediates the therapeutic efficacy of mesenchymal stem cell-derived extracellular vesicles against neonatal hyperoxic lung injury

We previously reported the role of vascular endothelial growth factor (VEGF) secreted by mesenchymal stem cells (MSCs) in protecting against neonatal hyperoxic lung injuries. Recently, the paracrine protective effect of MSCs was reported to be primarily mediated by extracellular vesicle (EV) secretion. However, the therapeutic efficacy of MSC-derived EVs and the role of the VEGF contained within EVs in neonatal hyperoxic lung injury have not been elucidated. The aim of the study was to determine whether MSC-derived EVs attenuate neonatal hyperoxic lung injury and, if so, whether this protection is mediated via the transfer of VEGF. We compared the therapeutic efficacy of MSCs, MSC-derived EVs with or without VEGF knockdown, and fibroblast-derived EVs in vitro with a rat lung epithelial cell line challenged with H₂O₂ and in vivo with newborn Sprague-Dawley rats exposed to hyperoxia (90%) for 14 days. MSCs (1 × 10⁵ cells) or EVs (20 µg) were administered intratracheally on postnatal day 5. The MSCs and MSC-derived EVs, but not the EVs derived from VEGF-knockdown MSCs or fibroblasts, attenuated the in vitro H₂O₂-induced L2 cell death and the in vivo hyperoxic lung injuries, such as impaired alveolarization and angiogenesis, increased cell death, and activated macrophages and proinflammatory cytokines. PKH67-stained EVs were internalized into vascular pericytes (22.7%), macrophages (21.3%), type 2 epithelial cells (19.5%), and fibroblasts (4.4%) but not into vascular endothelial cells. MSC-derived EVs are as effective as parental MSCs for attenuating neonatal hyperoxic lung injuries, and this protection was mediated primarily by the transfer of VEGF.

The Potentials and Caveats of Mesenchymal Stromal Cell-Based Therapies in the Preterm Infant

Preponderance of proinflammatory signals is a characteristic feature of all acute and resulting long-term morbidities of the preterm infant. The proinflammatory actions are best characterized for bronchopulmonary dysplasia (BPD) which is the chronic lung disease of the preterm infant with lifelong restrictions of pulmonary function and severe consequences for psychomotor development and quality of life. Besides BPD, the immature brain, eye, and gut are also exposed to inflammatory injuries provoked by infection, mechanical ventilation, and oxygen toxicity. Despite the tremendous progress in the understanding of disease pathologies, therapeutic interventions with proven efficiency remain restricted to a few drug therapies with restricted therapeutic benefit, partially considerable side effects, and missing option of applicability to the inflamed brain. The therapeutic potential of mesenchymal stromal cells (MSCs)—also known as mesenchymal stem cells—has attracted much attention during the recent years due to their anti-inflammatory activities and their secretion of growth and development-promoting factors. Based on a molecular understanding, this review summarizes the positive actions of exogenous umbilical cord-derived MSCs on the immature lung and brain and the therapeutic potential of reprogramming resident MSCs. The pathomechanistic understanding of MSC actions from the animal model is complemented by the promising results from the first phase I clinical trials testing allogenic MSC transplantation from umbilical cord blood. Despite all the enthusiasm towards this new therapeutic option, the caveats and outstanding issues have to be critically evaluated before a broad introduction of MSC-based therapies.

Mesenchymal stem cells in the pathogenesis and treatment of bronchopulmonary dysplasia: a clinical review

Advances in neonatal medicine have led to increased survival of infants born at the limits of viability, resulting in an increased incidence of bronchopulmonary dysplasia (BPD). BPD is a chronic lung disease of premature infants characterized by the arrest of alveolarization, fibroblast activation, and inflammation. BPD leads to significant morbidity and mortality in the neonatal period and is one of the leading causes of chronic lung disease in children. The past decade has brought a surge of trials investigating cellular therapies for the treatment of pulmonary diseases. Mesenchymal stem cells (MSCs) are of particular interest because of their ease of isolation, low immunogenicity, and anti-inflammatory and reparative properties. Clinical trials of MSCs have demonstrated short-term safety and tolerability; however, studies have also shown populations of MSCs with adverse pro-inflammatory and myofibroblastic characteristics. Cell-based therapies may represent the next breakthrough therapy for the treatment of BPD, however, there remain barriers to implementation as well as gaps in knowledge of the role of endogenous MSCs in the pathogenesis of BPD. Concurrent high-quality basic science, translational, and clinical studies investigating the fundamental pathophysiology underlying BPD, therapeutic mechanisms of exogenous MSCs, and logistics of translating cellular therapies will be important areas of future research.

Stem cell biology and regenerative medicine for neonatal lung diseases

Lung diseases remain one of the main causes of morbidity and mortality in neonates. Cell therapy and regenerative medicine have the potential to revolutionize the management of life-threatening and debilitating lung diseases that currently lack effective treatments. Over the past decade, the repair capabilities of stem/progenitor cells have been harnessed to prevent/rescue lung damage in experimental neonatal lung diseases. Mesenchymal stromal cells and amnion epithelial cells exert pleiotropic effects and represent ideal therapeutic cells for bronchopulmonary dysplasia, a multifactorial disease. Endothelial progenitor cells are optimally suited to promote lung vascular growth and attenuate pulmonary hypertension in infants with congenital diaphragmatic hernia or a vascular bronchopulmonary dysplasia phenotype. Induced pluripotent stem cells (iPSCs) are one of the most exciting breakthroughs of the past decade. Patient-specific iPSCs can be derived from somatic cells and differentiated into any cell type. iPSCs can be capitalized upon to develop personalized regenerative cell products for surfactant protein deficiencies-lethal lung disorders without treatment-that affect a single gene in a single cell type and thus lend themselves to phenotype-specific cell replacement. While the clinical translation has begun, more needs to be learned about the biology of these repair cells to make this translation successful.

The Therapeutic Potential of Stem Cells for Bronchopulmonary Dysplasia: "It's About Time" or "Not so Fast" ?

OBJECTIVE

While the survival of extremely premature infants has improved over the past decades, the rate of complications - especially for bronchopulmonary dysplasia (BPD) - remains unacceptably high. Over the past 50 years, no safe therapy has had a substantial impact on the incidence and severity of BPD.

METHODS

This may stem from the multifactorial disease pathogenesis and the increasing lung immaturity. Mesenchymal Stromal Cells (MSCs) display pleiotropic effects and show promising results in neonatal rodents in preventing or rescuing lung injury without adverse effects. Early phase clinical trials are now underway to determine the safety and efficacy of this therapy in extremely premature infants.

RESULTS AND CONCLUSION

This review summarizes our current knowledge about MSCs, their mechanism of action and the results of preclinical studies that provide the rationale for early phase clinical trials and discuss remaining gaps in our knowledge.

Mesenchymal stem cells for the prevention and treatment of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains a major complication of prematurity and currently lacks efficient treatments. Mesenchymal stem/stromal cells (MSCs) have been extensively explored as a potential therapy in several preclinical and clinical settings. Human and animal MSCs have been shown to prevent and treat lung injury in various preclinical models of lung diseases, including experimental BPD.

OBJECTIVES

To determine if MSCs, administered intravenously or endotracheally, are safe and effective in preventing or treating BPD, or both, in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 10), MEDLINE via PubMed (1966 to 6 November 2016), Embase (1980 to 6 November 2016), and CINAHL (1982 to 6 November 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We considered RCTs and quasi-RCTs investigating prevention or treatment of BPD, or both, in preterm infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality according to prespecified criteria.

MAIN RESULTS

We found no RCTs or quasi-RCTs addressing the use of MSCs for prevention or treatment of BPD in premature infants. Two RCTs are currently registered and ongoing.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine the safety and efficacy of MSCs in the treatment or prevention of BPD in premature infants. The results of the ongoing trials addressing this issue are expected in the near future.

Neurodevelopment at Age 10 Years of Children Born <28 Weeks With Fetal Growth Restriction

OBJECTIVES

We sought to evaluate the relationships between fetal growth restriction (FGR) (both severe and less severe) and assessments of cognitive, academic, and adaptive behavior brain function at age 10 years.

METHODS

At age 10 years, the Extremely Low Gestational Age Newborns Cohort Study assessed the cognitive function, academic achievement, social-communicative function, psychiatric symptoms, and overall quality of life of 889 children born before 28 weeks' gestation. A pediatric epileptologist also interviewed parents as part of a seizure evaluation. The 52 children whose birth weight z scores were <-2 were classified as having severe FGR, and the 113 whose birth weight z scores were between -2 and -1 were considered to have less severe FGR.

RESULTS

The more severe the growth restriction in utero, the lower the level of function on multiple cognitive and academic achievement assessments performed at age 10 years. Growth-restricted children were also more likely than their extremely preterm peers to have social awareness impairments, autistic mannerisms, autism spectrum diagnoses, difficulty with semantics and speech coherence, and diminished social and psychosocial functioning. They also more frequently had phobias, obsessions, and compulsions (according to teacher, but not parent, report).

CONCLUSIONS

Among children born extremely preterm, those with severe FGR appear to be at increased risk of multiple cognitive and behavioral dysfunctions at age 10 years, raising the possibility that whatever adversely affected their intrauterine growth also adversely affected multiple domains of cognitive and neurobehavioral development.

Bone Marrow Mononuclear Cells Transplantation in Treatment of Established Bronchopulmonary Dysplasia: A Case Report

Patient: Male, newborn

Final Diagnosis: Bronchopulmonary displasia

Symptoms: Difficult to breath • patient could not wean from oxygen/premature

Medication: —

Clinical Procedure: Bone marrow mononuclear cells transplantation

Specialty: Pulmonology