Therapeutic effect of placenta-derived mesenchymal stem cells on hypoxic-ischemic brain damage in rats

A Review of the Use of Extracellular Vesicles in the Treatment of Neonatal Diseases: Current State and Problems with Translation to the Clinic

Neonatal disorders, particularly those resulting from prematurity, pose a major challenge in health care and have a significant impact on infant mortality and long-term child health. The limitations of current therapeutic strategies emphasize the need for innovative treatments. New cell-free technologies utilizing extracellular vesicles (EVs) offer a compelling opportunity for neonatal therapy by harnessing the inherent regenerative capabilities of EVs. These nanoscale particles, secreted by a variety of organisms including animals, bacteria, fungi and plants, contain a repertoire of bioactive molecules with therapeutic potential. This review aims to provide a comprehensive assessment of the therapeutic effects of EVs and mechanistic insights into EVs from stem cells, biological fluids and non-animal sources, with a focus on common neonatal conditions such as hypoxic-ischemic encephalopathy, respiratory distress syndrome, bronchopulmonary dysplasia and necrotizing enterocolitis. This review summarizes evidence for the therapeutic potential of EVs, analyzes evidence of their mechanisms of action and discusses the challenges associated with the implementation of EV-based therapies in neonatal clinical practice.

Mesenchymal stem cell therapy in perinatal arterial ischemic stroke: systematic review of preclinical studies

BACKGROUND

Perinatal arterial ischemic stroke (PAIS) is a neurologic disorder leading to long-term complications. Mesenchymal stem cells (MSCs) have emerged as a novel therapeutic agent. This systematic review aims to determine the effects of stem cell-based interventions for the treatment of PAIS in preclinical studies.

METHODS

We included all controlled studies on MSCs in neonatal animals with PAIS. Functional outcome was the primary outcome. The literature search was performed in February 2021.

RESULTS

In the 20 included studies, MSCs were most frequently delivered via intracerebral injection (n = 9), 3 days after the induction of PAIS (n = 8), at a dose ranging from 5 × 104 to 5 × 106 cells. The meta-analysis showed an improvement on the cylinder rearing test (MD: -10.62; 95% CI: -14.38 to -6.86) and on the water maze test (MD: 1.31 MD; 95% CI: 0.80 to 1.81) in animals treated with MSCs compared to the control group animals.

CONCLUSION

MSCs appear to improve sensorimotor and cognitive performance in PAIS-injured animals; however, the certainty of the evidence is low. Registration of the protocol of preclinical studies, appropriate sample size calculation, rigorous randomization, and reporting of the data on animal sex and survival are warranted. PROSPERO registration number: CRD42021239642.

IMPACT

This is the first systematic review and meta-analysis of preclinical studies investigating the effects of MSCs in an experimental model of PAIS. MSCs appear to improve sensorimotor and cognitive performance in PAIS-injured neonatal animals. The certainty of the evidence is low due to high or unclear risk of bias in most domains.

Umbilical Cord Blood-Derived Cell Therapy for Perinatal Brain Injury: A Systematic Review & Meta-Analysis of Preclinical Studies

Perinatal brain injury is a major contributor to long-term adverse neurodevelopment. There is mounting preclinical evidence for use of umbilical cord blood (UCB)-derived cell therapy as potential treatment. To systematically review and analyse effects of UCB-derived cell therapy on brain outcomes in preclinical models of perinatal brain injury. MEDLINE and Embase databases were searched for relevant studies. Brain injury outcomes were extracted for meta-analysis to calculate standard mean difference (SMD) with 95% confidence interval (CI), using an inverse variance, random effects model. Outcomes were separated based on grey matter (GM) and white matter (WM) regions where applicable. Risk of bias was assessed using SYRCLE, and GRADE was used to summarise certainty of evidence. Fifty-five eligible studies were included (7 large, 48 small animal models). UCB-derived cell therapy significantly improved outcomes across multiple domains, including decreased infarct size (SMD 0.53; 95% CI (0.32, 0.74), p < 0.00001), apoptosis (WM, SMD 1.59; 95%CI (0.86, 2.32), p < 0.0001), astrogliosis (GM, SMD 0.56; 95% CI (0.12, 1.01), p = 0.01), microglial activation (WM, SMD 1.03; 95% CI (0.40, 1.66), p = 0.001), neuroinflammation (TNF-α, SMD 0.84; 95%CI (0.44, 1.25), p < 0.0001); as well as improved neuron number (SMD 0.86; 95% CI (0.39, 1.33), p = 0.0003), oligodendrocyte number (GM, SMD 3.35; 95 %CI (1.00, 5.69), p = 0.005) and motor function (cylinder test, SMD 0.49; 95 %CI (0.23, 0.76), p = 0.0003). Risk of bias was determined as serious, and overall certainty of evidence was low. UCB-derived cell therapy is an efficacious treatment in pre-clinical models of perinatal brain injury, however findings are limited by low certainty of evidence.

TLR4 Modulates Senescence and Paracrine Action in Placental Mesenchymal Stem Cells via Inhibiting Hedgehog Signaling Pathway in Preeclampsia

Preeclampsia (PE) is a heterogeneous disease closely associated with the accelerated senescence of the placentas. Placental mesenchymal stem cells (PMSCs) modulate placental development, which is abnormally senescent in PE together with abnormal paracrine. Both pivotal in the placenta development, Toll-like receptor 4 (TLR4) and Hedgehog (HH) pathway are also tightly involved in regulating cellular senescence. This study was aimed at demonstrating that TLR4/HH pathway modulated senescence of placentas and PMSCs in vitro and in vivo. Preeclamptic and normal PMSCs were isolated. Smoothed agonist (SAG) and cyclopamine were used to activate and inhibit HH pathway, respectively. Lipopolysaccharide (LPS) was used to activate TLR4 in vitro and establish the classic PE-like rat model. qRT-PCR, Western blotting, and immunofluorescence were used to detect the expression of TLR4 and HH components (SHH, SMO, and Gli1). Cellular biological function such as proliferation, apoptosis, and migration was compared. Cell cycle analysis, β-galactosidase staining, and the protein expressions of p16 and p53 were detected to analyze the cellular senescence. The secretion levels of human matrix metalloproteinase 9 (MMP-9) and soluble fms-like tyrosine kinase-1 (sFlt-1) were measured in the conditioned medium. Cell migration, invasion, and tube formation were analyzed in HTR8/SVneo cells or human umbilical vein endothelial cells (HUVECs). Our study demonstrated that activation of TLR4 accelerated senescence of PMSCs via suppressing HH pathway both in vitro and in vivo, accompanied by the detrimental paracrine to impair the uterine spiral artery remodeling and placental angiogenesis. Meanwhile, induction of HH pathway could alleviate PE-like manifestations, improve pregnancy outcomes, and ameliorate multiorgan injuries, suggesting that strengthening the HH pathway may serve as a potential therapy in PE.

Mesenchymal Stem/Stromal Cells and Their Role in Oxidative Stress Associated with Preeclampsia

Preeclampsia (PE) is a serious medically important disorder of human pregnancy, which features de novo pregnancy-induced hypertension and proteinuria. The severe form of PE can progress to eclampsia, a convulsive, life-threatening condition. When placental growth and perfusion are abnormal, the placenta experiences oxidative stress and subsequently secretes abnormal amounts of certain pro-angiogenic factors (eg, PlGF) as well as anti-angiogenic factors (eg, sFlt-1) that enter the maternal circulation. The net effect is damage to the maternal vascular endothelium, which subsequently manifests as the clinical features of PE. Other than delivery of the fetus and placenta, curative treatments for PE have not yet been forthcoming, which reflects the complexity of the clinical syndrome. A major source of reactive oxygen species that contributes to the widespread maternal vascular endothelium damage is the PE-affected decidua. The role of decidua-derived mesenchymal stem/stromal cells (MSC) in normotensive and pathological placenta development is poorly understood. The ability to respond to an environment of oxidative damage is a "universal property" of MSC but the biological mechanisms that MSC employ in response to oxidative stress are compromised in PE. In this review, we discuss how MSC respond to oxidative stress in normotensive and pathological conditions. We also consider the possibility of manipulating the oxidative stress response of abnormal MSC as a therapeutic strategy to treat preeclampsia.

Stem Cell Therapy for Neonatal Hypoxic-Ischemic Encephalopathy: A Systematic Review of Preclinical Studies

Neonatal hypoxic-ischemic encephalopathy (HIE) is an important cause of mortality and morbidity in the perinatal period. This condition results from a period of ischemia and hypoxia to the brain of neonates, leading to several disorders that profoundly affect the daily life of patients and their families. Currently, therapeutic hypothermia (TH) is the standard of care in developing countries; however, TH is not always effective, especially in severe cases of HIE. Addressing this concern, several preclinical studies assessed the potential of stem cell therapy (SCT) for HIE. With this systematic review, we gathered information included in 58 preclinical studies from the last decade, focusing on the ones using stem cells isolated from the umbilical cord blood, umbilical cord tissue, placenta, and bone marrow. Outstandingly, about 80% of these studies reported a significant improvement of cognitive and/or sensorimotor function, as well as decreased brain damage. These results show the potential of SCT for HIE and the possibility of this therapy, in combination with TH, becoming the next therapeutic approach for HIE. Nonetheless, few preclinical studies assessed the combination of TH and SCT for HIE, and the existent studies show some contradictory results, revealing the need to further explore this line of research.

The neuroprotective effect of mesenchymal stem cells is mediated through inhibition of apoptosis in hypoxic ischemic injury

BACKGROUND

Neonatal hypoxia ischemia causes severe brain damage. Stem cell therapy is a promising method for treating neuronal diseases. Clinical translation of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) for the recovery of neurons after hypoxic ischemic encephalopathy (HIE) may represent an effective therapy.

METHODS

Primary neurons were exposed to oxygen-glucose deprivation (OGD) and subsequently cocultured with UC-MSCs. Apoptosis was examined by Annexin V-FITC-PI. Genes related to apoptosis were detected using RT-PCR and western-blot analyses. Using an in vivo model, HIE was induced in postnatal day 7 mice, and UC-MSCs were transplanted via the intraventricular route. UC-MSC migration was investigated by immunofluorescence, and lesion volumes were measured by TTC staining. Apoptosis in injured brain cells was detected by the TUNEL assay. RT-PCR and ELISA were used to detect the expression of inflammatory factors in cells and animal tissues.

RESULTS

Flow cytometry analysis revealed that apoptosis in injured neurons was inhibited by UC-MSCs. The RT-PCR and western blot results indicated that coculture inhibited the expression of proapoptotic genes and upregulated expression of antiapoptotic genes. In the animal model, transplanted UC-MSCs migrated toward the cerebral lesion site and decreased the lesion extent in HIE. TUNEL staining showed that the MSC group exhibited significantly reduced numbers of TUNEL-positive cells. RT-PCR and ELISA showed that UC-MSCs inhibited the upregulation of TNF-α and IL-1β in response to hypoxic ischemic injury.

CONCLUSION

These results indicate that UC-MSCs exert neuroprotective effects against hypoxic ischemic injury by inhibiting apoptosis, and the mechanism appears to be through alleviating the inflammatory response.

microRNA-128 enhances neuroprotective effects of dexmedetomidine on neonatal mice with hypoxic-ischemic brain damage by targeting WNT1

OBJECTIVE

Hypoxic-ischemic brain damage (HIBD) is a major cause of acute mortality and chronic neurological morbidity in infants and children. Dexmedetomidine (DEX) is an effective choice in HIBD treatment. Recent findings have revealed that microRNA-128 (miR-128) is implicated in cerebral ischemia reperfusion. Hence, this study aimed to investigate the role of miR-128 in HIBD.

METHODS

HIBD models of neonatal mice were established. HIBD mice were treated with DEX, and injected with agomir (ago)-miR-128 or antagomir (anti)-miR-128 into the lateral ventricles to explore the influence of miR-128 on the neuroprotective effects of DEX on HIBD. Subsequently, the mice body weight, left/right (L/R) brain weight ratio, left-brain water content as well as learning and memory abilities were measured. Furthermore, the pathological changes of brain tissues and apoptosis rate of nerve cells were determined. The potential relationship between miR-128 and WNT1 was analyzed.

RESULTS

Over-expression of miR-128 caused an increase in mouse body weight, L/R brain weight ratio, and learning and memory abilities, while led to a decline in left-brain water content, brain tissue injury and apoptosis rate of nerve cells in DEX-treated HIBD mice. WNT1 was targeted and negatively regulated by miR-128. Silencing of WNT1 exerted the same effect as miR-128 on enhancing the neuroprotective effect of DEX on HIBD mice.

CONCLUSION

Collectively, miR-128 enhanced neuroprotective effect of DEX on HIBD neonatal mice by inhibiting WNT1.

Umbilical cord mesenchymal stem cells and umbilical cord blood mononuclear cells improve neonatal rat memory after hypoxia-ischemia

Current treatment options for hypoxic-ischemic encephalopathy (HIE) are limited. Human umbilical cord mesenchymal stem cells (UC-MSCs) and cord blood mononuclear cells (CB-MNCs) offer great potential for the treatment of many neurological diseases. The aim of the present study was to identify which cell type is more effective for the treatment of HIE. PKH26-labeled UC-MSCs and CB-MNCs were transplanted into rats with hypoxia-ischemia (HI)-induced brain damage. Apoptotic cell numbers in the brain, as labeled by TUNEL, were assessed. Myelination and gliosis were investigated using myelin basic protein and glial fibrillary acidic protein immunohistochemistry, respectively. The Morris water maze was used to assess animal learning abilities. Our data show that transplantation of UC-MSCs or CB-MNCs after HI reduced astrogliosis, prevented neuronal loss in the striatum, and markedly improved functional brain outcomes after a 28-day recovery period. Moreover, treatment with CB-MNCs increased the proportion of mature oligodendrocytes and improved myelination in cortical areas. Both UC-MSCs and CB-MNCs may result in the recovery of neurological function in HI rats. Based on our data, UC-MSCs and UCB-MNCs may be particularly effective stem cell subsets for treatment of neonatal HIE.

MicroRNA-140-5p elevates cerebral protection of dexmedetomidine against hypoxic-ischaemic brain damage via the Wnt/β-catenin signalling pathway

Hypoxia–ischaemia (HI) remains a major cause of foetal brain damage presented a scarcity of effective therapeutic approaches. Dexmedetomidine (DEX) and microRNA‐140‐5p (miR‐140‐5p) have been highlighted due to its potentially significant role in the treatment of cerebral ischaemia. This study was to investigate the role by which miR‐140‐5p provides cerebral protection using DEX to treat hypoxic–ischaemic brain damage (HIBD) in neonatal rats via the Wnt/β‐catenin signalling pathway. The HIBD rat models were established and allocated into various groups with different treatment plans, and eight SD rats into sham group. The learning and memory ability of the rats was assessed. Apoptosis and pathological changes in the hippocampus CA1 region and expressions of the related genes of the Wnt/β‐catenin signalling pathway as well as the genes responsible of apoptosis were detected. Compared with the sham group, the parameters of weight, length growth, weight ratio between hemispheres, the rate of reaching standard, as well as Bcl‐2 expressions, were all increased. Furthermore, observations of increased levels of cerebral infarction volume, total mortality rate, response times, total response duration, expressions of Wnt1, β‐catenin, TCF‐4, E‐cadherin, apoptosis rate of neurons, and Bax expression were elevated. Following DEX treatment, the symptoms exhibited by HIBD rats were ameliorated. miR‐140‐5p and si‐Wnt1 were noted to attenuate the progression of HIBD. Our study demonstrates that miR‐140‐5p promotes the cerebral protective effects of DEX against HIBD in neonatal rats by targeting the Wnt1 gene through via the negative regulation of the Wnt/β‐catenin signalling pathway.

Heme Oxygenase-1: Clinical Relevance in Ischemic Stroke

Stroke is the second-leading cause of death and a leading cause of serious long-term disability worldwide, with an increasing global burden due to the growing and aging population. However, strict eligibility criteria for current treatment opportunities make novel therapeutic approaches desirable. Oxidative stress plays a pivotal role during cerebral ischemia, eventually leading to neuronal injury and cell death. The significant correlation between redox imbalance and ischemic stroke has led to various treatment strategies targeting the endogenous antioxidant system in order to ameliorate the adverse prognosis in patients with cerebral infarction. One of the most extensively investigated cellular defense pathway in this regard is the Nrf2-heme oxygenase-1 (HO-1) axis. In this review, our aim is to focus on the potential clinical relevance of targeting the HO-1 pathway in ischemic stroke.

The Placenta as an Organ and a Source of Stem Cells and Extracellular Matrix: A Review

The placenta is a temporal, dynamic and diverse organ with important immunological features that facilitate embryonic and fetal development and survival, notwithstanding the fact that several aspects of its formation and function closely resemble tumor progression. Placentation in mammals is commonly used to characterize the evolution of species, including insights into human evolution. Although most placentas are discarded after birth, they are a high-yield source for the isolation of stem/progenitor cells and are rich in extracellular matrix (ECM), representing an important resource for regenerative medicine purposes. Interactions among cells, ECM and bioactive molecules regulate tissue and organ generation and comprise the foundation of tissue engineering. In the present article, differences among several mammalian species regarding the placental types and classifications, phenotypes and potency of placenta-derived stem/progenitor cells, placental ECM components and current placental ECM applications were reviewed to highlight their potential clinical and biomedical relevance.

Transplantation of placenta-derived mesenchymal stem cells reduces hypoxic-ischemic brain damage in rats by ameliorating the inflammatory response

Hypoxic-ischemic brain damage (HIBD) is a common cause of infant death. The purpose of our research was to explore the immunoregulatory mechanism of placenta-derived mesenchymal stem cells (PD-MSCs) in HIBD treatment. Seven-day-old rat pups were randomly divided into HIBD, PD-MSC, fibroblast, and control groups. Forty-eight hours after HIBD induction, cells at a density of 5 × 104 cells/10 µl were injected into the cerebral tissue in the PD-MSC and fibroblast groups. The TNF-α, interleukin- 17 (IL-17), interferon-γ (IFN-γ), and IL-10 levels were detected through quantitative real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Regulatory T cell (Tregs) populations were detected through flow cytometry, and forkhead box P3 (Foxp3) was measured through western blot analysis. Behavioral tests and gross and pathological examinations showed that PD-MSC treatment exerted significantly stronger neuroprotective effects than the other treatments. The expression levels of pro-inflammatory cytokines were substantially upregulated after HI injury. Compared with fibroblast treatment, PD-MSC treatment inhibited the production of pro-inflammatory cytokines and increased the production of IL-10 in the ischemic hemispheres and peripheral blood serum (all P < 0.01). Flow cytometry results showed a notable increase in the number of Tregs within the spleen of the HIBD group. Moreover, the number of Tregs and the Foxp3 expression levels were higher in the PD-MSC treatment group than in the HIBD and fibroblast groups (all P < 0.01). Our research suggests that the mechanism of PD-MSC treatment for HIBD partially involves inflammatory response suppression.