Human amnion cells reverse acute and chronic pulmonary damage in experimental neonatal lung injury

Reinitiating lung development: a novel approach in the management of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the predominant chronic lung disease in preterm infants, linked with various adverse long-term outcomes. Multiple prenatal and postnatal risk factors can impede lung development, leading to BPD. Current management of BPD relies heavily on pharmacotherapies and alterations in ventilatory strategies. However, these interventions only mitigate BPD symptoms without addressing underlying alveolar, vascular, structural, and functional deficiencies. Given the retarded lung development in infants with BPD and the limitations of existing modalities, new therapeutic approaches are imperative. The induced differentiation of stem/progenitor cells and the spatiotemporal expression patterns of growth factors associated with lung developmental processes are critical for lung development reactivation in BPD, which focuses on stimulating pulmonary vasculogenesis and alveolarization. This review summarizes the process of lung development and offers a comprehensive overview of advancements in therapies designed to reinitiate lung development in BPD. Furthermore, we assessed the potential of these therapies for maintaining lung homeostasis and effectively restoring pulmonary structure and function through stem/progenitor cells and growth factors, which have been widely researched.

Therapeutic potential of extracellular vesicles derived from human amniotic epithelial cells for perinatal cerebral and pulmonary injury

Lung and brain injury that occurs during the perinatal period leads to lifelong disability and is often driven and/or exacerbated by inflammation. Human amniotic epithelial cells (hAEC), which demonstrate immunomodulatory, anti-fibrotic, and regenerative capabilities, are being explored as a therapeutic candidate for perinatal injury. However, limitations regarding scalable manufacturing, storage, transport, and dose-related toxicity have impeded clinical translation. Isolated therapeutic extracellular vesicles (EVs) from stem and stem-like cells are thought to be key paracrine mediators of therapeutic efficacy. The unique characteristics of EVs suggest that they potentially circumvent the limitations of traditional cell-based therapies. However, given the novelty of EVs as a therapeutic, recommendations around ideal methods of production, isolation, storage, and delivery have not yet been created by regulatory agencies. In this concise review, we discuss the pertinence and limitations of cell-based therapeutics in perinatal medicine. We also review the preclinical evidence supporting the use of therapeutic EVs for perinatal therapy. Further, we summarize the arising considerations regarding adequate cell source, biodistribution, isolation and storage methods, and regulatory roadblocks for the development of therapeutic EVs.

BPD: Latest Strategies of Prevention and Treatment

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common long-term complication of extreme preterm birth. It is associated with lifelong multisystemic consequences. Advances in neonatal care have not reduced the incidence of BPD and no new breakthrough therapy has been successfully translated into the clinic in recent decades.

SUMMARY

Current evidence demonstrates benefit of new modalities of first-line noninvasive positive pressure ventilation, selected strategies of postnatal corticosteroid administration, alternative surfactant delivery methods, and caffeine. Promising emerging therapies that are being translated from bench to bedside include mesenchymal stromal cells (MSCs), insulin-like growth factor 1/binding protein-3 (IGF-1/IGFBP-3), and interleukin 1 receptor (IL-1R) antagonist (anakinra). Strong preclinical data support efficacy of MSCs in attenuating neonatal lung injury. Early-phase clinical trials have already demonstrated safety and feasibility in preterm infants. Phase II studies that aimed at demonstrating efficacy are currently underway. Both IGF-1/IGFBP-3 and IL-1R antagonist present with biological plausibility and animal data of efficacy. Phase I/II clinical trials are currently recruiting patients.

KEY MESSAGES

Early noninvasive respiratory support, late systemic dexamethasone, less invasive surfactant administration, and caffeine are proven strategies in reducing the risk of BPD. Potentially disruptive therapies - MSCs, IGF-1/IGFBP-3, and anakinra - are being advanced to clinical trials and their efficacy in remains to be demonstrated. Continued research efforts are needed in the growing population of extremely preterm infants at risk of developing BPD.

Grimm S, Coarfa C, Theis F, Simon LM, Shivanna B. Leveraging Integrated RNA Sequencing to Decipher Adrenomedullin's Protective Mechanisms in Experimental Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease commonly affecting premature infants, with limited therapeutic options and increased long-term consequences. Adrenomedullin (Adm), a proangiogenic peptide hormone, has been found to protect rodents against experimental BPD. This study aims to elucidate the molecular and cellular mechanisms through which Adm influences BPD pathogenesis using a lipopolysaccharide (LPS)-induced model of experimental BPD in mice. Bulk RNA sequencing of Adm-sufficient (wild-type or Adm+/+) and Adm-haplodeficient (Adm+/-) mice lungs, integrated with single-cell RNA sequencing data, revealed distinct gene expression patterns and cell type alterations associated with Adm deficiency and LPS exposure. Notably, computational integration with cell atlas data revealed that Adm-haplodeficient mouse lungs exhibited gene expression signatures characteristic of increased inflammation, natural killer (NK) cell frequency, and decreased endothelial cell and type II pneumocyte frequency. Furthermore, in silico human BPD patient data analysis supported our cell type frequency finding, highlighting elevated NK cells in BPD infants. These results underscore the protective role of Adm in experimental BPD and emphasize that it is a potential therapeutic target for BPD infants with an inflammatory phenotype.

Human amnion epithelial cell therapy reduces hypertension-induced vascular stiffening and cognitive impairment

Vascular inflammation and fibrosis are hallmarks of hypertension and contribute to the development of cardiovascular disease and cognitive impairment. However, current anti-hypertensive drugs do not treat the underlying tissue damage, such as inflammation-associated fibrosis. Human amnion epithelial cells have several properties amenable for treating vascular pathology. This study tested the effect of amnion epithelial cells on vascular pathology and cognitive impairment during hypertension. Male C57Bl6 mice (8-12 weeks) were administered vehicle (saline; n = 58) or angiotensin II (0.7 mg/kg/d, n = 56) subcutaneously for 14 d. After surgery, a subset of mice were injected with 106 amnion epithelial cells intravenously. Angiotensin II infusion increased systolic blood pressure, aortic pulse wave velocity, accumulation of aortic leukocytes, and aortic mRNA expression of collagen subtypes compared to vehicle-infused mice (n = 9-11, P < 0.05). Administration of amnion epithelial cells attenuated these effects of angiotensin II (P < 0.05). Angiotensin II-induced cognitive impairment was prevented by amnion epithelial cell therapy (n = 7-9, P < 0.05). In the brain, amnion epithelial cells modulated some of the inflammatory genes that angiotensin II promoted differential expression of (n = 6, p-adjusted < 0.05). These findings suggest that amnion epithelial cells could be explored as a potential therapy to inhibit vascular pathology and cognitive impairment during hypertension.

Advances in neonatal cell therapies: Proceedings of the First Neonatal Cell Therapies Symposium (2022)

Despite considerable advances, there is a need to improve the outcomes of newborn infants, especially related to prematurity, encephalopathy and other conditions. In principle, cell therapies have the potential to protect, repair, or sometimes regenerate vital tissues; and improve or sustain organ function. In this review, we present highlights from the First Neonatal Cell Therapies Symposium (2022). Cells tested in preclinical and clinical studies include mesenchymal stromal cells from various sources, umbilical cord blood and cord tissue derived cells, and placental tissue and membrane derived cells. Overall, most preclinical studies suggest potential for benefit, but many of the cells tested were not adequately defined, and the optimal cell type, timing, frequency, cell dose or the most effective protocols for the targeted conditions is not known. There is as yet no clinical evidence for benefit, but several early phase clinical trials are now assessing safety in newborn babies. We discuss parental perspectives on their involvement in these trials, and lessons learnt from previous translational work of promising neonatal therapies. Finally, we make a call to the many research groups around the world working in this exciting yet complex field, to work together to make substantial and timely progress to address the knowledge gaps and move the field forward. IMPACT: Survival of preterm and sick newborn infants is improving, but they continue to be at high risk of many systemic and organ-specific complications. Cell therapies show promising results in preclinical models of various neonatal conditions and early phase clinical trials have been completed or underway. Progress on the potential utility of cell therapies for neonatal conditions, parental perspectives and translational aspects are discussed in this paper.

Human amniotic epithelial stem cells: Hepatic differentiation and regenerative properties in liver disease treatment

The placenta and the extraembryonic tissues represent a valuable source of cells for regenerative medicine. In particular, the amniotic membrane possesses cells with stem cells characteristics that have attracted research attention. Human amniotic epithelial cells (hAECs) have unique and desirable features that position them over other stem cells, not only because of the unlimited potential supplied of, the easy access to placental tissues, and the minimal ethical and legal barriers associated, but also due to the embryonic stem cells markers expression and their ability to differentiate into the three germ layers. In addition, they are non-tumorigenic and have immunomodulatory and anti-inflammatory properties. Hepatic failure is one of the major causes of morbidity and mortality worldwide. Organ transplantation is the best way to treat acute and chronic liver failure, but there are several associated obstacles. Stem cells have been highlighted as alternative hepatocytes source because of their potential for hepatogenic differentiation. HAECs, in particular, have some properties that make them suitable for hepatocyte differentiation. In this work, we review the general characteristics of the epithelial stem cells isolated from human amniotic membrane as well as their ability to differentiate to hepatic cells. We also revise their regenerative properties, with the focus on their potential application in the liver disease treatment.

Potential Therapeutic Effects of Human Amniotic Epithelial Cells on Gynecological Disorders Leading to Infertility or Abortion

The induction of feto-maternal tolerance, fetal non-immunogenicity, and the regulation of mother's immune system are essential variables in a successful pregnancy. Fetal membranes have been used as a source of stem cells and biological components in recent decades. Human amniotic epithelial cells (hAEC) have stem/progenitor characteristics like those found in the amniotic membrane. Based on their immunomodulatory capabilities, recent studies have focused on the experimental and therapeutic applications of hAECs in allograft transplantation, autoimmune disorders, and gynecological problems such as recurrent spontaneous abortion (RSA), recurrent implantation failure (RIF), and premature ovarian failure (POF). This review discusses some of the immunomodulatory features and therapeutic potential of hAECs in preventing infertility, miscarriage, and implantation failure by controlling the maternal immune system.

Perinatal Stem Cell Therapy to Treat Type 1 Diabetes Mellitus: A Never-Say-Die Story of Differentiation and Immunomodulation

Human term placenta and other postpartum-derived biological tissues are promising sources of perinatal cells with unique stem cell properties. Among the massive current research on stem cells, one medical focus on easily available stem cells is to exploit them in the design of immunotherapy protocols, in particular for the treatment of chronic non-curable human diseases. Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells and perinatal cells can be harnessed both to generate insulin-producing cells for beta cell replenishment and to regulate autoimmune mechanisms via immunomodulation capacity. In this study, the strong points of cells derived from amniotic epithelial cells and from umbilical cord matrix are outlined and their potential for supporting cell therapy development. From a basic research and expert stem cell point of view, the aim of this review is to summarize information regarding the regenerative medicine field, as well as describe the state of the art on possible cell therapy approaches for diabetes.

Human amniotic epithelial cells exert anti-cancer effects through secretion of immunomodulatory small extracellular vesicles (sEV)

We identified here mechanism by which hAECs exert their anti-cancer effects. We showed that vaccination with live hAEC conferred effective protection against murine colon cancer and melanoma but not against breast cancer in an orthotopic cancer cell inoculation model. hAEC induced strong cross-reactive antibody response to CT26 cells, but not against B16F10 and 4T1 cells. Neither heterotopic injection of tumor cells in AEC-vaccinated mice nor vaccination with hAEC lysate conferred protection against melanoma or colon cancer. Nano-sized AEC-derived small-extracellular vesicles (sEV) (AD-sEV) induced apoptosis in CT26 cells and inhibited their proliferation. Co-administration of AD-sEV with tumor cells substantially inhibited tumor development and increased CTL responses in vaccinated mice. AD-sEV triggered the Warburg’s effect leading to Arginine consumption and cancer cell apoptosis. Our results clearly showed that it is AD-sEV but not the cross-reactive immune responses against tumor cells that mediate inhibitory effects of hAEC on cancer development. Our results highlight the potential anti-cancer effects of extracellular vesicles derived from hAEC.

Anti-cancer effects of hAEC depend on cancer type.

Cross-reactive humoral responses do not mediate anti-cancer effects of hAEC.

Anti-cancer effects of hAECs are mainly mediated by small-extracellular vesicles (sEV).

hAEC-derived sEV (AD-sEV) trigger the Warburg’s effect leading to Arginine consumption and cancer cell apoptosis.

AD-sEV substantially inhibits tumor development and increases survival and CTL responses.

Proceedings of the ISCT scientific signature series symposium, "Advances in cell and gene therapies for lung diseases and critical illnesses": International Society for Cell & Gene Therapy, Burlington VT, US, July 16, 2021

The ISCT Scientific Signature Series Symposium "Advances in Cell and Gene Therapies for Lung Diseases and Critical Illnesses" was held as an independent symposium in conjunction with the biennial meeting, "Stem Cells, Cell Therapies, and Bioengineering in Lung Biology and Diseases," which took place July 12-15, 2021, at the University of Vermont. This is the third Respiratory System-based Signature Series event; the first 2, "Tracheal Bioengineering, the Next Steps" and "Cellular Therapies for Pulmonary Diseases and Critical Illnesses: State of the Art of European Science," took place in 2014 and 2015, respectively. Cell- and gene-based therapies for respiratory diseases and critical illnesses continue to be a source of great promise and opportunity. This reflects ongoing advancements in understanding of the mechanisms by which cell-based therapies, particularly those using mesenchymal stromal cells (MSCs), can mitigate different lung injuries and the increasing sophistication with which preclinical data is translated into clinical investigations. This also reflects continuing evolution in gene transfer vectors, including those designed for in situ gene editing in parallel with those targeting gene or cell replacement. Therefore, this symposium convened global thought leaders in a forum designed to catalyze communication and collaboration to bring the greatest possible innovation and value of cell- and gene-based therapies for patients with respiratory diseases and critical illnesses.

Assessing the impact of gestational age of donors on the efficacy of amniotic epithelial cell-derived extracellular vesicles in experimental bronchopulmonary dysplasia

Background and rationale

Extracellular vesicles (EVs) are a potential cell-free regenerative medicine. Human amniotic epithelial cells (hAECs) are a viable source of cell therapy for diseases like bronchopulmonary dysplasia (BPD). However, little is known about the impact of gestational age of the donor on the quality of hAEC-derived EVs.

Aims

To determine the impact of gestational age on hAEC-derived EVs in experimental BPD.

Results

Term hAEC-derived EVs displayed a significantly higher density of surface epitopes (CD142 and CD133) and induced greater macrophage phagocytosis compared to preterm hAEC-EVs. However, T cell proliferation was more significantly suppressed by preterm hAEC-EVs. Using a model of experimental BPD, we observed that term but not preterm hAEC-EVs improved tissue-to-airspace ratio and septal crest density. While both term and preterm hAEC-EVs reduced the levels of inflammatory cytokines on postnatal day 7, the improvement in lung injury was associated with increased type II alveolar cells which was only observed in term hAEC-EV treatment group. Furthermore, only neonatal term hAEC-EVs reduced airway hyper-responsiveness, mitigated pulmonary hypertension and protected against right ventricular hypertrophy at 6 weeks of age.

Conclusion

Term hAEC-EVs, but not preterm hAEC-EVs, have therapeutic efficacy in a mouse model of BPD-like lung injury. Therefore, the impact of donor criteria should be considered when applying perinatal cells-derived EV therapy for clinical use.

Stem-Cell Therapy for Bronchopulmonary Dysplasia (BPD) in Newborns

Premature newborns are at a higher risk for the development of respiratory distress syndrome (RDS), acute lung injury (ALI) associated with lung inflammation, disruption of alveolar structure, impaired alveolar growth, lung fibrosis, impaired lung angiogenesis, and development of bronchopulmonary dysplasia (BPD) with severe long-term developmental adverse effects. The current therapy for BPD is limited to supportive care including high-oxygen therapy and pharmacotherapy. Recognizing more feasible treatment options to improve lung health and reduce complications associated with BPD is essential for improving the overall quality of life of premature infants. There is a reduction in the resident stem cells in lungs of premature infants with BPD, which strongly suggests a critical role of stem cells in BPD pathogenesis; this warrants the exploration of the potential therapeutic use of stem-cell therapy. Stem-cell-based therapies have shown promise for the treatment of many pathological conditions including acute lung injury and BPD. Mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (EVs) including exosomes are promising and effective therapeutic modalities for the treatment of BPD. Treatment with MSCs and EVs may help to reduce lung inflammation, improve pulmonary architecture, attenuate pulmonary fibrosis, and increase the survival rate.

Human placenta-derived amniotic epithelial cells as a new therapeutic hope for COVID-19-associated acute respiratory distress syndrome (ARDS) and systemic inflammation

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has become in the spotlight regarding the serious early and late complications, including acute respiratory distress syndrome (ARDS), systemic inflammation, multi-organ failure and death. Although many preventive and therapeutic approaches have been suggested for ameliorating complications of COVID-19, emerging new resistant viral variants has called the efficacy of current therapeutic approaches into question. Besides, recent reports on the late and chronic complications of COVID-19, including organ fibrosis, emphasize a need for a multi-aspect therapeutic method that could control various COVID-19 consequences. Human amniotic epithelial cells (hAECs), a group of placenta-derived amniotic membrane resident stem cells, possess considerable therapeutic features that bring them up as a proposed therapeutic option for COVID-19. These cells display immunomodulatory effects in different organs that could reduce the adverse consequences of immune system hyper-reaction against SARS-CoV-2. Besides, hAECs would participate in alveolar fluid clearance, renin–angiotensin–aldosterone system regulation, and regeneration of damaged organs. hAECs could also prevent thrombotic events, which is a serious complication of COVID-19. This review focuses on the proposed early and late therapeutic mechanisms of hAECs and their exosomes to the injured organs. It also discusses the possible application of preconditioned and genetically modified hAECs as well as their promising role as a drug delivery system in COVID-19. Moreover, the recent advances in the pre-clinical and clinical application of hAECs and their exosomes as an optimistic therapeutic hope in COVID-19 have been reviewed.

The Significance of Epidermal Growth Factor in Noninvasively Obtained Amniotic Fluid Predicting Respiratory Outcomes of Preterm Neonates

Preterm premature rupture of membranes (PPROM) interrupts normal lung development, resulting in neonatal respiratory morbidity. Although post-PPROM risks have been researched, only a few studies have investigated noninvasively obtained amniotic fluid (AF) to predict neonatal outcomes. In this study, we aimed to determine whether epidermal growth factor (EGF) in vaginally-collected AF is a significant predictor of neonatal respiratory outcomes after PPROM. We analyzed EGF in vaginally-obtained AF from 145 women with PPROM at 22−34 weeks of gestation. The following neonatal outcomes were included: respiratory distress syndrome, surfactant need, duration and type of respiratory support, and bronchopulmonary dysplasia. We found that EGF concentration was associated with gestational age, and its medians were lower in neonates with respiratory morbidities than unaffected ones. EGF concentrations gradually declined, the lowest being in the most clinically ill patients. EGF < 35 pg/mL significantly predicted the odds of severe respiratory outcomes. EGF in noninvasively collected AF may be a reliable predictor for respiratory outcomes of preterm neonates with PPROM before 34 weeks of gestation. The results of our study may have implications for further research both in noninvasive amniotic fluid analysis and the management of patients after PPROM.

Placental tissue stem cells and their role in neonatal diseases

Neonatal diseases such as hypoxic ischemic encephalopathy, diseases of prematurity and congenital disorders carry increased morbidity and mortality. Despite technological advancements, their incidence remains largely unabated. Stem cell (SC) interventions are novel therapies in the neonatal world. In pre-clinical models of neonatal diseases, SC applications have shown encouraging results. SC sources vary, with the bone marrow being the most utilized. However, the ability to harvest bone marrow SCs from neonates is limited. Placental-tissue derived SCs (PTSCs), provide an alternative and highly attractive source. Human placentas, the cornerstone of fetal survival, are abundant with such cells. Comparing to adult pools, PTSCs exhibit increased potency, decreased immunogenicity and stronger anti-inflammatory effects. Several types of PTSCs have been identified, with mesenchymal stem cells being the most utilized population. This review will focus on PTSCs and their pre-clinical and clinical applications in neonatology.

Addressing the liver progenitor cell response and hepatic oxidative stress in experimental non-alcoholic fatty liver disease/non-alcoholic steatohepatitis using amniotic epithelial cells

Background

Non-alcoholic fatty liver disease is the most common liver disease globally and in its inflammatory form, non-alcoholic steatohepatitis (NASH), can progress to cirrhosis and hepatocellular carcinoma (HCC). Currently, patient education and lifestyle changes are the major tools to prevent the continued progression of NASH. Emerging therapies in NASH target known pathological processes involved in the progression of the disease including inflammation, fibrosis, oxidative stress and hepatocyte apoptosis. Human amniotic epithelial cells (hAECs) were previously shown to be beneficial in experimental models of chronic liver injury, reducing hepatic inflammation and fibrosis. Previous studies have shown that liver progenitor cells (LPCs) response plays a significant role in the development of fibrosis and HCC in mouse models of fatty liver disease. In this study, we examined the effect hAECs have on the LPC response and hepatic oxidative stress in an experimental model of NASH.

Methods

Experimental NASH was induced in C57BL/6 J male mice using a high-fat, high fructose diet for 42 weeks. Mice received either a single intraperitoneal injection of 2 × 10⁶ hAECs at week 34 or an additional hAEC dose at week 38. Changes to the LPC response and oxidative stress regulators were measured.

Results

hAEC administration significantly reduced the expansion of LPCs and their mitogens, IL-6, IFNγ and TWEAK. hAEC administration also reduced neutrophil infiltration and myeloperoxidase production with a concurrent increase in heme oxygenase-1 production. These observations were accompanied by a significant increase in total levels of anti-fibrotic IFNβ in mice treated with a single dose of hAECs, which appeared to be independent of c-GAS-STING activation.

Conclusions

Expansion of liver progenitor cells, hepatic inflammation and oxidative stress associated with experimental NASH were attenuated by hAEC administration. Given that repeated doses did not significantly increase efficacy, future studies assessing the impact of dose escalation and/or timing of dose may provide insights into clinical translation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02476-6.

The effect of human amnion epithelial cells on lung development and inflammation in preterm lambs exposed to antenatal inflammation

Background

Lung inflammation and impaired alveolarization are hallmarks of bronchopulmonary dysplasia (BPD). We hypothesize that human amnion epithelial cells (hAECs) are anti-inflammatory and reduce lung injury in preterm lambs born after antenatal exposure to inflammation.

Methods

Pregnant ewes received either intra-amniotic lipopolysaccharide (LPS, from E.coli 055:B5; 4mg) or saline (Sal) on day 126 of gestation. Lambs were delivered by cesarean section at 128 d gestation (term ~150 d). Lambs received intravenous hAECs (LPS/hAECs: n = 7; 30x10⁶ cells) or equivalent volumes of saline (LPS/Sal, n = 10; or Sal/Sal, n = 9) immediately after birth. Respiratory support was gradually de-escalated, aimed at early weaning from mechanical ventilation towards unassisted respiration. Lung tissue was collected 1 week after birth. Lung morphology was assessed and mRNA levels for inflammatory mediators were measured.

Results

Respiratory support required by LPS/hAEC lambs was not different to Sal/Sal or LPS/Sal lambs. Lung tissue:airspace ratio was lower in the LPS/Sal compared to Sal/Sal lambs (P<0.05), but not LPS/hAEC lambs. LPS/hAEC lambs tended to have increased septation in their lungs versus LPS/Sal (P = 0.08). Expression of inflammatory cytokines was highest in LPS/hAECs lambs.

Conclusions

Postnatal administration of a single dose of hAECs stimulates a pulmonary immune response without changing ventilator requirements in preterm lambs born after intrauterine inflammation.

Human Amnion Epithelial Cells Produce Soluble Factors that Enhance Liver Repair by Reducing Fibrosis While Maintaining Regeneration in a Model of Chronic Liver Injury

Human amnion epithelial cells (hAECs) exert potent antifibrotic and anti-inflammatory effects when transplanted into preclinical models of tissue fibrosis. These effects are mediated in part via the secretion of soluble factors by hAECs which modulate signaling pathways and affect cell types involved in inflammation and fibrosis. Based on these reports, we hypothesized that these soluble factors may also support liver regeneration during chronic liver injury. To test this, we characterized the effect of both hAECs and hAEC-conditioned medium (CM) on liver repair in a mouse model of carbon tetrachloride (CCl₄)-induced fibrosis. Liver repair was assessed by liver fibrosis, hepatocyte proliferation, and the liver progenitor cell (LPC) response. We found that the administration of hAECs or hAEC-CM reduced liver injury and fibrosis, sustained hepatocyte proliferation, and reduced LPC numbers during chronic liver injury. Additionally, we undertook in vitro studies to document both the cell-cell and paracrine-mediated effects of hAECs on LPCs by investigating the effects of co-culturing the LPCs and hAECs and hAEC-CM on LPCs. We found little change in LPCs co-cultured with hAECs. In contrast, hAEC-CM enhances LPC proliferation and differentiation. These findings suggest that paracrine factors secreted by hAECs enhance liver repair by reducing fibrosis while promoting regeneration during chronic liver injury.

Impact of chemically defined culture media formulations on extracellular vesicle production by amniotic epithelial cells

The therapeutic properties of cell derived extracellular vesicles (EVs) make them promising cell-free alternative to regenerative medicine. However, clinical translation of this technology relies on the ability to manufacture EVs in a scalable, reproducible, and cGMP-compliant manner. To generate EVs in sufficient quantity, a critical step is the selection and development of culture media, where differences in formulation may influence the EV manufacturing process. In this study, we used human amniotic epithelial cells (hAECs) as a model system to explore the effect of different formulations of chemically defined, commercially sourced media on EV production. Here, we determined that cell viability and proliferation rate are not reliable quality indicators for EV manufacturing. The levels of tetraspanins and epitope makers of EVs were significantly impacted by culture media formulations. Mass spectrometry-based proteomic profiling revealed proteome composition of hAEC-EVs and the influence of media formulations on composition of EV proteome. This study has revealed critical aspects including cell viability and proliferation rate, EV yield, and tetraspanins, surface epitopes and proteome composition of EVs influenced by media formulations, and further insight into standardised EV production culture media that should be considered in clinical-grade scalable EV manufacture for generation of therapeutic EVs.

Prematurity negatively affects regenerative properties of human amniotic epithelial cells in the context of lung repair

There is a growing appreciation of the role of lung stem/progenitor cells in the development and perpetuation of chronic lung disease including idiopathic pulmonary fibrosis. Human amniotic epithelial cells (hAECs) were previously shown to improve lung architecture in bleomycin-induced lung injury, with the further suggestion that hAECs obtained from term pregnancies possessed superior anti-fibrotic properties compared with their preterm counterparts. In the present study, we aimed to elucidate the differential effects of hAECs from term and preterm pregnancies on lung stem/progenitor cells involved in the repair. Here we showed that term hAECs were better able to activate bronchioalveolar stem cells (BASCs) and type 2 alveolar epithelial cells (AT2s) compared with preterm hAECs following bleomycin challenge. Further, we observed that term hAECs restored TGIF1 and TGFβ2 expression levels, while increasing c-MYC expression despite an absence of significant changes to Wnt/β-catenin signaling. In vitro, term hAECs increased the average size and numbers of BASC and AT2 colonies. The gene expression levels of Wnt ligands were higher in term hAECs, and the expression levels of BMP4, CCND1 and CDC42 were only increased in the BASC and AT2 organoids co-cultured with hAECs from term pregnancies but not preterm pregnancies. In conclusion, term hAECs were more efficient at activating the BASC niche compared with preterm hAECs. The impact of gestational age and/or complications leading to preterm delivery should be considered when applying hAECs and other gestational tissue-derived stem and stem-like cells therapeutically.

Stem cells and COVID-19: are the human amniotic cells a new hope for therapies against the SARS-CoV-2 virus?

A new coronavirus respiratory disease (COVID-19) caused by the SARS-CoV-2 virus, surprised the entire world, producing social, economic, and health problems. The COVID-19 triggers a lung infection with a multiple proinflammatory cytokine storm in severe patients. Without effective and safe treatments, COVID-19 has killed thousands of people, becoming a pandemic. Stem cells have been suggested as a therapy for lung-related diseases. In particular, mesenchymal stem cells (MSCs) have been successfully tested in some clinical trials in patients with COVID-19. The encouraging results positioned MSCs as a possible cell therapy for COVID-19. The amniotic membrane from the human placenta at term is a valuable stem cell source, including human amniotic epithelial cells (hAECs) and human mesenchymal stromal cells (hAMSCs). Interestingly, amnion cells have immunoregulatory, regenerative, and anti-inflammatory properties. Moreover, hAECs and hAMSCs have been used both in preclinical studies and in clinical trials against respiratory diseases. They have reduced the inflammatory response and restored the pulmonary tissue architecture in lung injury in vivo models. Here, we review the existing data about the stem cells use for COVID-19 treatment, including the ongoing clinical trials. We also consider the non-cellular therapies that are being applied. Finally, we discuss the human amniotic membrane cells use in patients who suffer from immune/inflammatory lung diseases and hypothesize their possible use as a successful treatment against COVID-19.

Endoscopic atomization of mesenchymal stromal cells: in vitro study for local cell therapy of the lungs

BACKGROUND AIMS

Cell-based therapies of pulmonary diseases with mesenchymal stromal cells (MSCs) are increasingly under experimental investigation. In most of these, MSCs are administered intravenously or by direct intratracheal instillation. A parallel approach is to administer the cells into the lung by endoscopic atomization (spraying). In a previous study, the authors developed a flexible endoscopic atomization device that allows administration of respiratory epithelial cells in the lungs with high survival.

METHODS

In this study, the authors evaluated the feasibility of spraying MSCs with two different endoscopic atomization devices (air and pressure atomization). Following atomization, cell viability was evaluated with live/dead staining. Subsequent effects on cytotoxicity, trilineage differentiation and expression of MSC-specific markers as well as on MSC metabolic activity and morphology were analyzed for up to 7 days.

RESULTS

MSC viability immediately after spraying and subsequent metabolic activity for 7 days was not influenced by either of the devices. Slightly higher cytotoxicity rates could be observed for pressure-atomized compared with control and air-atomized MSCs over 7 days. Flow cytometry revealed no changes in characteristic MSC cell surface marker expression, and morphology remained unchanged. Standard differentiation into osteocytes, chondrocytes and adipocytes was inducible after atomization.

CONCLUSIONS

In the literature, a minimal survival of 50% was previously defined as the cutoff value for successful cell atomization. This is easily met with both of the authors' devices, with more than 90% survival. Thus, there is a potential role for atomization in intrapulmonary MSC-based cell therapies, as it is a feasible and easily utilizable approach based on clinically available equipment.

Characteristics and Therapeutic Potential of Human Amnion-Derived Stem Cells

Stem cells including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and adult stem cells (ASCs) are able to repair/replace damaged or degenerative tissues and improve functional recovery in experimental model and clinical trials. However, there are still many limitations and unresolved problems regarding stem cell therapy in terms of ethical barriers, immune rejection, tumorigenicity, and cell sources. By reviewing recent literatures and our related works, human amnion-derived stem cells (hADSCs) including human amniotic mesenchymal stem cells (hAMSCs) and human amniotic epithelial stem cells (hAESCs) have shown considerable advantages over other stem cells. In this review, we first described the biological characteristics and advantages of hADSCs, especially for their high pluripotency and immunomodulatory effects. Then, we summarized the therapeutic applications and recent progresses of hADSCs in treating various diseases for preclinical research and clinical trials. In addition, the possible mechanisms and the challenges of hADSCs applications have been also discussed. Finally, we highlighted the properties of hADSCs as a promising source of stem cells for cell therapy and regenerative medicine and pointed out the perspectives for the directions of hADSCs applications clinically.

A protocol for cell therapy infusion in neonates

Cell therapies for neonatal morbidities are progressing to early phase clinical trials. However, protocols for intravenous (IV) delivery of cell therapies to infants have not been evaluated. It has been assumed the cell dose prescribed is the dose delivered. Early in our clinical trial of human amnion epithelial cells (hAECs), we observed cells settling in the syringe and IV tubing used to deliver the suspension. The effect on dose delivery was unknown. We aimed to quantify this observation and determine an optimal protocol for IV delivery of hAECs to extremely preterm infants. A standard pediatric infusion protocol was modeled in the laboratory. A syringe pump delivered the hAEC suspension over 60 minutes via a pediatric blood transfusion set (200‐μm filter and 2.2 mL IV line). The infusion protocol was varied by agitation methods, IV‐line volumes (0.2‐2.2 mL), albumin concentrations (2% vs 4%), and syringe orientations (horizontal vs vertical) to assess whether these variables influenced the dose delivered. The influence of flow rate (3‐15 mL/h) was assessed after other variables were optimized. The standard infusion protocol delivered 17.6% ± 9% of the intended hAEC dose. Increasing albumin concentration to 4%, positioning the syringe and IV line vertically, and decreasing IV‐line volume to 0.6 mL delivered 99.7% ± 13% of the intended hAEC dose. Flow rate did not affect dose delivery. Cell therapy infusion protocols must be considered. We describe the refinement of a cell infusion protocol that delivers intended cell doses and could form the basis of future neonatal cell delivery protocols.

A Review of Placenta and Umbilical Cord-Derived Stem Cells and the Immunomodulatory Basis of Their Therapeutic Potential in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a devastating lung disorder of preterm infants as a result of an aberrant reparative response following exposures to various antenatal and postnatal insults. Despite sophisticated medical treatment in this modern era, the incidence of BPD remains unabated. The current strategies to prevent and treat BPD have met with limited success. The emergence of stem cell therapy may be a potential breakthrough in mitigating this complex chronic lung disorder. Over the last two decades, the human placenta and umbilical cord have gained increasing attention as a highly potential source of stem cells. Placenta-derived stem cells (PDSCs) and umbilical cord-derived stem cells (UCDSCs) display several advantages such as immune tolerance and are generally devoid of ethical constraints, in addition to their stemness qualities. They possess the characteristics of both embryonic and mesenchymal stromal/stem cells. Recently, there are many preclinical studies investigating the use of these cells as therapeutic agents in neonatal disease models for clinical applications. In this review, we describe the preclinical and clinical studies using PDSCs and UCDSCs as treatment in animal models of BPD. The source of these stem cells, routes of administration, and effects on immunomodulation, inflammation and regeneration in the injured lung are also discussed. Lastly, a brief description summarized the completed and ongoing clinical trials using PDSCs and UCDSCs as therapeutic agents in preventing or treating BPD. Due to the complexity of BPD, the development of a safe and efficient therapeutic agent remains a major challenge to both clinicians and researchers.

Application of human amniotic epithelial cells in regenerative medicine: a systematic review

Human amniotic epithelial cells (hAECs) derived from placental tissues have gained considerable attention in the field of regenerative medicine. hAECs possess embryonic stem cell-like proliferation and differentiation capabilities, and adult stem cell-like immunomodulatory properties. Compared with other types of stem cell, hAECs have special advantages, including easy isolation, plentiful numbers, the obviation of ethical debates, and non-immunogenic and non-tumorigenic properties. During the past two decades, the therapeutic potential of hAECs for treatment of various diseases has been extensively investigated. Accumulating evidence has demonstrated that hAEC transplantation helps to repair and rebuild the function of damaged tissues and organs by different molecular mechanisms. This systematic review focused on summarizing the biological characteristics of hAECs, therapeutic applications, and recent advances in treating various tissue injuries and disorders. Relevant studies published in English from 2000 to 2020 describing the role of hAECs in diseases and phenotypes were comprehensively sought out using PubMed, MEDLINE, and Google Scholar. According to the research content, we described the major hAEC characteristics, including induced differentiation plasticity, homing and differentiation, paracrine function, and immunomodulatory properties. We also summarized the current status of clinical research and discussed the prospects of hAEC-based transplantation therapies. In this review, we provide a comprehensive understanding of the therapeutic potential of hAECs, including their use for cell replacement therapy as well as secreted cytokine and exosome biotherapy. Moreover, we showed that the powerful immune-regulatory function of hAECs reveals even more possibilities for their application in the treatment of immune-related diseases. In the future, establishing the optimal culture procedure, achieving precise and accurate treatment, and enhancing the therapeutic potential by utilizing appropriate preconditioning and/or biomaterials would be new challenges for further investigation.

Hyaluronic acid ameliorates the proliferative ability of human amniotic epithelial cells through activation of TGF-β/BMP signaling

Human amniotic epithelial cells (hAECs) are a useful and noncontroversial source of stem cells for cell therapy and regenerative medicine, but their limited proliferative ability hinders the acquisition of adequate quantities of cells for clinical use due to not expressing telomerase in hAECs. Our previous study showed that hyaluronic acid (HA), an important component of the extracellular matrix, promoted the proliferation of human amniotic mesenchymal stem cells. Herein, we hypothesize that HA might improve the proliferative capability of hAECs. In the present study, the role of HA on the proliferation of human amniotic epithelial cells (hAECs) in vitro was investigated for the first time. HA at molecular weight of 300 kDa showed an obvious pro-proliferation effect on hAECs. Furthermore, HA not only kept phenotypic characteristics and differentiation capabilities of hAECs, but significantly promoted the secretion of the anti-inflammatory factors such as IL-10 and TGF-β1, and the expression of stem cell pluripotent factors such as Oct4 and Nanog. Analysis of PCR microarray data and RT-qPCR validation showed that TGF-β/BMP signaling was activated in the presence of HA. Further study showed that SB431542, an inhibitor of the TGF-β/BMP signaling, significantly suppressed the mRNA expression of TGFBR3, BMP4, BMP7, BMPR1B, SMAD3, SMAD4, and the pro-proliferative effect of HA on hAECs. These data suggest that HA is a safe and effective enhancer for in vitro expansion of hAECs, whose regulatory mechanism involves the TGF-β/BMP signaling.

Cell therapy for the preterm infant: promise and practicalities

Recent decades have seen the rapid progress of neonatal intensive care, and the survival rates of the most preterm infants are improving. This improvement is associated with changing patterns of morbidity and new phenotypes of bronchopulmonary dysplasia and preterm brain injury are recognised. Inflammation and immaturity are known contributors to their pathogenesis. However, a new phenomenon, the exhaustion of progenitor cells is emerging as an important factor. Current therapeutic approaches do not adequately address these new mechanisms of injury. Cell therapy, that is the use of stem and stem-like cells, with its potential to both repair and prevent injury, offers a new approach to these challenging conditions. This review will examine the rationale for cell therapy in the extremely preterm infant, the preclinical and early clinical evidence to support its use in bronchopulmonary dysplasia and preterm brain injury. Finally, it will address the challenges in translating cell therapy from the laboratory to early clinical trials.

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.

Is Umbilical Cord Blood Therapy an Effective Treatment for Early Lung Injury in Growth Restriction?

Fetal growth restriction (FGR) and prematurity are often co-morbidities, and both are risk factors for lung disease. Despite advances in early delivery combined with supportive ventilation, rates of ventilation-induced lung injury (VILI) remain high. There are currently no protective treatments or interventions available that target lung morbidities associated with FGR preterm infants. Stem cell therapy, such as umbilical cord blood (UCB) cell administration, demonstrates an ability to attenuate inflammation and injury associated with VILI in preterm appropriately grown animals. However, no studies have looked at the effects of stem cell therapy in growth restricted newborns. We aimed to determine if UCB treatment could attenuate acute inflammation in the first 24 h of ventilation, comparing effects in lambs born preterm following FGR with those born preterm but appropriately grown (AG). Placental insufficiency (FGR) was induced by single umbilical artery ligation in twin-bearing ewes at 88 days gestation, with twins used as control (appropriately grown, AG). Lambs were delivered preterm at ~126 days gestation (term is 150 days) and randomized to either immediate euthanasia (unventilated controls, AG_UVC and FGR_UVC) or commenced on 24 h of gentle supportive ventilation (AG_V and FGR_V) with additional cohorts receiving UCB treatment at 1 h (AG_CELLS, FGR_CELLS). Lungs were collected at post-mortem for histological and biochemical examination. Ventilation caused lung injury in AG lambs, as indicated by decreased septal crests and elastin density, as well as increased inflammation. Lung injury in AG lambs was attenuated with UCB therapy. Ventilated FGR lambs also sustained lung injury, albeit with different indices compared to AG lambs; in FGR, ventilation reduced septal crest density, reduced alpha smooth muscle actin density and reduced cell proliferation. UCB treatment in ventilated FGR lambs further decreased septal crest density and increased collagen deposition, however, it increased angiogenesis as evidenced by increased vascular endothelial growth factor (VEGF) expression and vessel density. This is the first time that a cell therapy has been investigated in the lungs of growth restricted animals. We show that the uterine environment can alter the response to both secondary stress (ventilation) and therapy (UCB). This study highlights the need for further research on the potential impact of novel therapies on a growth restricted offspring.

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.

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

Bronchopulmonary dysplasia (BPD) is the most common cause of morbidity and mortality in preterm infants. A key histopathological feature of BPD is stunted late lung development, where the process of alveolarization-the generation of alveolar gas exchange units-is impeded, through mechanisms that remain largely unclear. As such, there is interest in the clarification both of the pathomechanisms at play in affected lungs, and the mechanisms of de novo alveoli generation in healthy, developing lungs. A better understanding of normal and pathological alveolarization might reveal opportunities for improved medical management of affected infants. Furthermore, disturbances to the alveolar architecture are a key histopathological feature of several adult chronic lung diseases, including emphysema and fibrosis, and it is envisaged that knowledge about the mechanisms of alveologenesis might facilitate regeneration of healthy lung parenchyma in affected patients. To this end, recent efforts have interrogated clinical data, developed new-and refined existing-in vivo and in vitro models of BPD, have applied new microscopic and radiographic approaches, and have developed advanced cell-culture approaches, including organoid generation. Advances have also been made in the development of other methodologies, including single-cell analysis, metabolomics, lipidomics, and proteomics, as well as the generation and use of complex mouse genetics tools. The objective of this review is to present advances made in our understanding of the mechanisms of lung alveolarization and BPD over the period 1 January 2017-30 June 2019, a period that spans the 50th anniversary of the original clinical description of BPD in preterm infants.

Human Amnion Epithelial Cell Therapy for Chronic Liver Disease

Liver fibrosis is a common consequence of chronic liver disease. Over time, liver fibrosis can develop into liver cirrhosis. Current therapies for liver fibrosis are limited, and liver transplant is the only curative therapy for patients who progress to end-stage disease. A potential approach to treat chronic liver disease with increasing interest is cell-based therapy. Among the multiple cell types which have been proposed for therapeutic uses, human amnion epithelial cells and amniotic fluid-derived mesenchymal cells are promising. These cells are highly abundant, and their use poses no ethical concern. Furthermore, they exert potent anti-inflammatory and antifibrotic effects in animal models of liver injury. This review highlights the therapeutic characteristics and discusses how human amnion epithelial cells can be utilised as a therapeutic tool for chronic liver disease.

Human Amniotic Epithelial Cell-Derived Exosomes Restore Ovarian Function by Transferring MicroRNAs against Apoptosis

Premature ovarian failure (POF) is one of the most common complications among female patients with tumors treated with chemotherapy and requires advanced treatment strategies. Human amniotic epithelial cell (hAEC)-based therapy mediates tissue regeneration in a variety of diseases, and increasing evidence suggests that the therapeutic efficacy of hAECs mainly depends on paracrine action. This study aimed to identify exosomes derived from hAECs and explored the therapeutic potential in ovaries damaged by chemotherapy and the underlying molecular mechanism. hAEC-derived exosomes exhibited a cup- or sphere-shaped morphology with a mean diameter of 100 nm and were positive for Alix, CD63, and CD9. hAEC exosomes increased the number of follicles and improved ovarian function in POF mice. During the early stage of transplantation, hAEC exosomes significantly inhibited granulosa cell apoptosis, protected the ovarian vasculature from damage, and were involved in maintaining the number of primordial follicles in the injured ovaries. Enriched microRNAs (miRNAs) existed in hAEC exosomes, and target genes were enriched in phosphatidylinositol signaling and apoptosis pathways. Studies in vitro demonstrated that hAEC exosomes inhibited chemotherapy-induced granulosa cell apoptosis via transferring functional miRNAs, such as miR-1246. Our findings demonstrate that hAEC-derived exosomes have the potential to restore ovarian function in chemotherapy-induced POF mice by transferring miRNAs.

Human amnion cells for the prevention of bronchopulmonary dysplasia: a protocol for a phase I dose escalation study

INTRODUCTION

Bronchopulmonary dysplasia (BPD), an important sequela of preterm birth, is associated with long-term abnormalities of lung function and adverse neurodevelopmental outcomes. Inflammation, inhibition of secondary septation and vascular maldevelopment play key roles in the pathogenesis of BPD. Human amnion epithelial cells (hAECs), stem-like cells, derived from placental tissues are able to modulate the inflammatory milieu and, in preclinical studies of BPD-like injury, restore lung architecture and function. Allogeneic hAECs may present a new preventative and reparative therapy for BPD.

METHODS AND ANALYSIS

In this two centre, phase I cell dose escalation study we will evaluate the safety of intravenous hAEC infusions in preterm infants at high risk of severe BPD. Twenty-four infants born at less than 29 weeks' gestation will each receive intravenous hAECs beginning day 14 of life. We will escalate the dose of cells contained in a single intravenous hAEC infusion in increments from 2 million cells/kg to 10 million cells/kg. Further dose escalation will be achieved with repeat infusions given at 5 day intervals to a maximum total dose of 30 million cells/kg (three infusions). Safety is the primary outcome. Infants will be followed-up until 2 years corrected age. Additional outcome measures include a description of infants' cytokine profile following hAEC infusion, respiratory outcomes including BPD and pulmonary hypertension and other neonatal morbidities including neurodevelopmental assessment at 2 years.

ETHICS AND DISSEMINATION

This study was approved on the June12th, 2018 by the Human Research Ethics Committee of Monash Health and Monash University. Recruitment commenced in August 2018 and is expected to take 18 months. Accordingly, follow-up will be completed mid-2022. The findings of this study will be disseminated via peer-reviewed journals and at conferences.

PROTOCOL VERSION

5, 21 May 2018.

TRIAL REGISTRATION NUMBER

ACTRN12618000920291; Pre-results.

Endothelial stromelysin1 regulation by the forkhead box-O transcription factors is crucial in the exudative phase of acute lung injury

Enhanced vascular permeability is associated with inflammation and edema in alveoli during the exudative phase of acute respiratory distress syndrome (ARDS). Mechanisms leading to the endothelial contribution on the early exudative stage of ARDS are not precise. We hypothesized that modulation of endothelial stromelysin1 expression and activity by Akt1-forkhead box-O transcription factors 1/3a (FoxO1/3a) pathway could play a significant role in regulating pulmonary edema during the initial stages of acute lung injury (ALI). We utilized lipopolysaccharide (LPS)-induced mouse ALI model in vivo and endothelial barrier resistance measurements in vitro to determine the specific role of the endothelial Akt1-FoxO1/3a-stromelysin1 pathway in ALI. LPS treatment of human pulmonary endothelial cells resulted in increased stromelysin1 and reduced tight junction claudin5 involving FoxO1/3a, associated with decreased trans-endothelial barrier resistance as determined by electric cell-substrate impedance sensing technology. In vivo, LPS-induced lung edema was significantly higher in endothelial Akt1 knockdown (EC-Akt1^-/-) compared to wild-type mice, which was reversed upon treatment with FoxO inhibitor (AS1842856), stromelysin1 inhibitor (UK356618) or with shRNA-mediated FoxO1/3a depletion in the mouse lungs. Overall, our study provides the hope that targeting FoxO and styromelysin1 could be beneficial in the treatment of ALI.

Celecoxib Protects Hyperoxia-Induced Lung Injury via NF-κB and AQP1

Objective: There is an increasing incidence of bronchopulmonary dysplasia (BDP) in preterm infants in China, which is the key issue affecting their survival rate and life quality. This study was performed to better understand the mechanism of protective effect of celecoxib on hyperoxia induced injury. Methods: Hyperoxia BPD model was established using newborn Sprague-Dawley (SD) rats exposed to high O₂ level (85%). Celecoxib treatment was also conducted. Histology of lung tissue samples were analyzed. Functional studies were systematically performed using the lung tissues and A549 cells. Results: Hyperoxia disrupted lung development in SD rats. Celecoxib alleviated the damaged lung development. NF-κB and Aquaporin (AQP) 1 were identified as the pathways in the hyperoxia-induced lung injury. We have shown that hyperoxia activated NF-κB pathway through increased nucleus translocation and repressed AQP1 expression. On the contrary, celecoxib inhibited NF-κB phosphorylation and nucleus translocation and increased AQP1 expression through inhibiting COX2 activity. Additionally, celecoxib also rescued apoptosis induced by hyperoxia. Conclusion: Our study identified NF-κB and AQP1 as the pathways in the hyperoxia-induced lung injury in the hyperoxia BPD model SD rats and it provided a better understanding of the protective effect of celecoxib. It suggests NF-κB and AQP1 may be as potential targets for treating newborns with BPD.

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.

Macrophage Immunomodulation: The Gatekeeper for Mesenchymal Stem Cell Derived-Exosomes in Pulmonary Arterial Hypertension?

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by remodeling of the pulmonary arteries, increased pulmonary infiltrates, loss of vascular cross-sectional area, and elevated pulmonary vascular resistance. Despite recent advances in the management of PAH, there is a pressing need for the development of new tools to effectively treat and reduce the risk of further complications. Dysregulated immunity underlies the development of PAH, and macrophages orchestrate both the initiation and resolution of pulmonary inflammation, thus, manipulation of lung macrophage function represents an attractive target for emerging immunomodulatory therapies, including cell-based approaches. Indeed, mesenchymal stem cell (MSC)-based therapies have shown promise, effectively modulating the macrophage fulcrum to favor an anti-inflammatory, pro-resolving phenotype, which is associated with both histological and functional benefits in preclinical models of pulmonary hypertension (PH). The complex interplay between immune system homeostasis and MSCs remains incompletely understood. Here, we highlight the importance of macrophage function in models of PH and summarize the development of MSC-based therapies, focusing on the significance of MSC exosomes (MEx) and the immunomodulatory and homeostatic mechanisms by which such therapies may afford their beneficial effects.

First-In-Human Administration of Allogeneic Amnion Cells in Premature Infants With Bronchopulmonary Dysplasia: A Safety Study

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that mainly affects premature babies who require ventilator support. The pathogenesis of BPD is complex but includes vascular maldevelopment, alveolarization arrest, and lung inflammation. There is no cure for BPD. Clinical care is limited to supportive respiratory measures. A population of stem-like cells derived from placental membranes, human amnion epithelial cells (hAECs), has shown therapeutic promise in preclinical models of BPD. With a view to future efficacy trials, we undertook a first-in-human clinical trial of hAECs in babies with BPD to assess the safety of these cells. In a single-center, open-label phase I trial, we administered allogeneic hAECs (1 × 10⁶ per kilogram bodyweight) by intravenous infusion to six premature babies with BPD. The primary outcomes of the study were focused on safety, including local site reaction, anaphylaxis, infection, features of rejection, or tumor formation. Outcomes to discharge from neonatal unit were studied. The hAECs were well tolerated. In the first baby, there was transient cardiorespiratory compromise during cell administration consistent with a pulmonary embolic event. Following changes to cell administration methods, including introduction of an inline filter, and reducing the cell concentration and the rate of cell infusion, no such events were observed in the subsequent five babies. We did not see evidence of any other adverse events related to cell administration. Allogeneic hAECs can be safely infused into babies with established BPD. Future randomized clinical trials to assess efficacy in this patient population are justified. Stem Cells Translational Medicine 2018;7:628-635.