Sage Journals: Discover world-class research

Abstract

Cerebral palsy (CP) includes a group of persistent non-progressive disorders affecting movement, muscle tone, and/or posture. The total economic loss during the life-span of an individual with CP places a heavy financial burden on such patients and their families worldwide; however, a complete cure is still lacking. Umbilical cord blood (UCB)-based interventions are emerging as a scientifically plausible treatment and possible cure for CP. Stem cells have been used in many experimental CP animal models and achieved good results. Compared with other types of stem cells, those from UCB have advantages in terms of treatment safety and efficacy, ethics, non-neoplastic proliferation, accessibility, ease of preservation, and regulation of immune responses, based on findings in animal models and clinical trials. Currently, the use of UCB-based interventions for CP is limited as the components of UCB are complex and possess different therapeutic mechanisms. These can be categorized by three aspects: homing and neuroregeneration, trophic factor secretion, and neuroprotective effects. Our review summarizes the features of active components of UCB and their therapeutic mechanism of action. This review highlights current research findings and clinical evidence regarding UCB that contribute to treatment suggestions, inform decision-making for therapeutic interventions, and help to direct future research.

Keywords

umbilical cord blood cerebral palsy stem cells cell transplantation mechanism

Introduction

Cerebral palsy (CP) is a group of persistent disorders caused by brain injury during prenatal or postnatal periods. CP affects movement, muscle tone, and/or posture, and results from non-progressive disturbances of the developing central nervous system (CNS)¹. The earliest description of the disorder is attributed to the orthopedic surgeon William Little in 1862². The prevalence of CP in countries with advanced medical care is 2.22–2.90 per 1000, and is likely higher in economically disadvantaged locations³. Generally, hypoxia-induced brain damage, genetic factors, mutations, and several other hypothesized theories including infection/inflammation could lead to hypoplastic brain tissue, resulting in loss of neuron function⁴. CP can be divided into five types based on motor dysfunction (ICD-10)⁵. According to statistics, in addition to neurological symptoms, patients with CP also have other symptoms, such as: pain (75%), intellectual disability (50%), inability to walk (33%), inability to talk (25%), epilepsy (25%), incontinence (25%), and blindness (10%)⁴. More than 100,000 Americans less than 18 years of age are suffering neurologic dysfunctions due to CP⁶, while the life-span total economic loss from all new CP cases amounted to US$ 2–4 billion in China in 2003⁷, placing a heavy financial burden on both developed and developing countries around the world. CP has become a major neurological disease that is harmful to children’s health⁸.

Stem cells have been used in many experimental CP animal models and achieved good results, depending on two essential properties: self-renewal (the capacity to generate identical cells) and multipotency (the capacity to generate many cell types).

Embryonic stem cells (ESCs) are considered the gold standard for pluripotency as they are able to differentiate into any cell type. However, three points limit their application: the possibility of undifferentiated ESCs leading to teratoma formation; the main source of ESCs, stillbirth, requiring ethical supervision; and the difficulty of creating a completely homogenous ESC culture⁹. Like ESCs, clinical application of induced pluripotent stem cells (iPSCs) has also been limited due to oncogenes that generate tumors¹⁰.

It has been demonstrated that mesenchymal stem cells (MSCs) can also undergo adipogenesis, chondrogenesis, and osteogenesis upon induction, and secrete biologically active molecules. MSCs were first identified in bone marrow (BM)¹¹ and subsequently isolated from human and animal tissues such as umbilical cord blood (UCB), umbilical cord matrix (Wharton’s jelly), adipose tissue, dental pulp, peripheral blood, and synovial fluid^12

–15. The Mesenchymal and Tissue Stem Cell Committee of the International Society for Cellular Therapy proposes minimum criteria to define human MSCs: First, MSCs must be plastic-adherent when maintained in standard culture conditions. Second, MSCs must express CD105, CD73, and CD90, and lack expression of CD45, CD34, CD14, CD11b, CD79alpha, CD19, and HLA-DR surface molecules. Third, MSCs must differentiate into osteoblasts, adipocytes, and chondroblasts in vitro¹⁶. However, the sampling process is invasive and affected by donor-derived tissue from BM. Moreover, MSCs easily age and have a limited lifespan¹⁷.

Like BM, human UCB (hUCB) is a complex internal environment rich in a variety of stem/progenitor cell populations¹⁸, such as hematopoietic stem cells (HSCs), endothelial progenitor cells (EPCs), UCB monocytes (including T regulatory cells (Tregs) and monocyte-derived suppressor cells (MDSCs)) and MSCs^19,20. The cellular fraction of the UCB has been referred to as a mononuclear cell (MNC) fraction that was collected from red blood cells and plasma²¹.

When UCB cells are transplanted into the body, they are thought to play several roles: regenerative or regeneration support; tropic and nutritional functions in “homing”; or acting in a paracrine manner and regulating inflammatory effects and protection²². Numerous studies have scrutinized the neuroregenerative and neuroprotective potential of UCBs for treating CP, perinatal hypoxic-ischemic encephalopathy (HIE), periventricular leukomalacia, and adult stroke^23
–25. Here, we review the recent literature the current mechanisms underlying UCB-related stem cell types or components during CP-related treatment in order to evaluate the evidence for directing future studies on CP and treatment decision-making.

Discussion

UCB Composition Selection and Treatment Mechanism

The UCB components involved in cell therapy research are shown in Table 1. Compared with other types of stem cells, those from the UCB have advantages in terms of CP treatment safety and efficacy^22,25,34, ethics³⁵, non-neoplastic proliferation, accessibility, ease of preservation³⁶, and regulation of immune responses²⁵, based on findings in animal models and clinical trials^28,37

–40. In animal studies, UCB cell therapy has made substantial progress (migration to sites⁴¹, improvement of functional loss⁴², and prevention of white matter damage⁴³). Encouragingly, in clinical trials, UCB therapy has been proven to be a safe, feasible, and potentially effective treatment for CP, particularly in motor function recovery in patients⁴⁴ and in post-acute phase neonatal brain injury²².

Table 1.

The UCB Components Involved in the Research of Cell Therapy.

Cells	Proliferative potential	Related specific molecules	Differentiation potential
CB-MSCs²⁶	>10 generations	Positive for CD13, CD29, CD44, CD49e, CD54, CD73, CD90, CD10, CD166 and HLA-ABC Negative for CD14, CD31, CD34, CD45, CD49d, CD80, CD86, CD106, HLA-DR	osteoblasts, chondrocytes, adipocytes, myoblasts and nerve cells
CB-USSCs²⁷	Multiply population >40	Positive for CD13, CD29, CD44, CD49e, CD90, CD105, vimentin, CK8, CK18, CD10 and FLK1 Negative for CD14, CD33, CD34, CD45, CD49b, CD49c, CD49d, CD49f, CD50, CD62E, CD62 L, CD62P, CD106, CD117, glycophorin A and HLA-DR	osteoblasts, chondrocytes, adipocytes, cardiomyocytes, purkinje cells, liver and nerve cells
CB-CBEs²⁸	168 times, The second generation	Positive for: CD34, CD133, CD164, SSEA-3, SSEA-4, Tral-60 and Tra1-81, Oct-4 Negative for: CD2, CD3, CD7, CD16, CD33, CD38 CD45, CD56, SSEA-1	bone, fat, skeletal muscle, blood vessels, liver, pancreas and nerve cells
CB-MPCs²⁹	>28 times in 12 weeks	Positive for: CD14, CD31, CD44, CD45 and CD54 Negative for: CD49a, CD62E, CD73, CD90 and CD104	osteogenesis, endothelium, liver and nerve cells
CB-EPCs³⁰	–	Positive for: CD14, CD31, CD34, CD133, VEGFR-2, Tie-1/2, VE-cadherin	blood brain barrier
CB-Tregs²¹	--	Positive for: CD14, CD80, CD83, CD86, HLA-DR, CD11b(MAC-1), Gr-1	--
CB-MDSCs³¹	--	Positive for: CD11b(MAC-1), Gr-1	--
Umbilical vein MSCs³²	>20 generations	Positive for: CD13, CD29, CD44, CD49e, CD54, CD73, CD90, CD105, CD166 and HLA-ABC Negative for: CD14, CD31, CD34, CD45, CD49d, CD51/61, CD106, CD133, Cadherin-5, glycophorin A, HLA-DR and KDR
WJ-MSCs³³	Multiply population>80	Positive for: CD10, CD13, CD29, CD44, CD51,CD73, CD90, CD105Negative for: CD14, CD31, CD33, CD34, CD38, CD40, CD40 L, CD45, CD56, CD80, CD86, CD117, HLA-DR	osteoblasts, adipocytes, chondrocytescardiomyocytes and nerve cells

CB-MSCs: umbilical cord blood-derived mesenchymal stem cells; CB-USSCs: umbilical cord blood-derived unrestricted somatic stem cells; CB-CBEs: umbilical cord-derived embryonic-like stem cells; CB-MPCs: umbilical cord blood-derived multipotent progenitor cells; CB-EPCs: umbilical cord blood-derived endothelial progenitor cells; CB-Tregs: umbilical cord blood-derived T regulatory cells; CB-MDSCs: umbilical vein MSCs; WJ-MSCs: Wharton’s jelly-derived mesenchymal stem cells; SSEA: stage-specific embryonic antigen; HLA: human leukocyte antigen; VEGF: vascular endothelial growth factor; MAC-1: macrophage-1 antigen.

The treatment mechanism can be summarized as follows:

Enhancement of Neuroregeneration by Homing

The stem cell niche is a special microenvironment that is suitable for stem cells. It mainly includes adjacent cells, extracellular matrix, and various cytokines. Stem cells achieve physiological steady-state growth, renewal, and differentiation through different signaling pathways including stromal-derived factor-1 (SDF-1)/ chemokine (C-X-C motif) (CXCR4), monocyte chemoattractant protein (MCP)-3/ cinnamoyl-CoA reductase (CCR), and hepatocyte growth factor (HGF) /c-met^45
–47. Chemotaxis refers to the concentration gradient of the ligands formed around the injured site by the release of inflammatory factors and chemokines surrounding the blood-activated stem cells. The homing effect of stem cells is the entire process of directed migration of the activated stem cells after injection into the target brain tissue along the concentration gradient, and performing regenerative functions⁴⁸.

The homing process begins with shear-resistant adhesive interactions flowing between cells and the vascular endothelium at the target tissue. Homing receptors expressed both on flowing cells (stem cells in blood) and related endothelial co-receptors cause cell-tethering and rolling contacts, thus mediating the interactions. Activation of integrins (including integrin β1) which play important roles in cell adhesion, migration, and chemotaxis set the anchorage for engrafted cells to make a hard adhesion. Finally, fixed “flowing cells” achieve their function through extravasation⁴⁹.

MSCs express the most common immune cell homing chemokine receptors including CXCR4, and the expression of SDF-1 after hypoxia-ischemia is significantly increased in the injured cerebral hemisphere and is mainly associated with astrocytes and glial cells^50
–52. Transplanted hUCB cells expressing the SDF-1 receptor CXCR4 migrate to the site of injury within 24 hours after induction of injury, further suggesting that SDF-1 is a potential chemokine for hUCB cell migration⁵³.

Immunohistochemical methods and small animal imaging systems have been used to track the distribution of hMSCs in the large blood vessels of brain injury after homing. The distribution of MSCs can be detected after transplantation of green fluorescent protein (GFP)-containing cells into the rat ventricles. Ten days after transplantation, MSCs with positive GFP expression could be seen in large vessels, and vascular endothelial growth factors were also higher in the transplanted group than in the control group⁵⁴. In addition, Rahimzadeh et al. reported that transplantation of autologous MSCs in arrangement by HSCs improved HSC engraftment⁴⁹ and resulted in the production of anti-inflammatory macrophages for increasing tissue repair⁵⁵.

The effect of upregulating CXCR4 contributes to stem cell homing and colonization to damaged tissue. Intravenous delivery of genetically modified MSCs expressing CXCR4 proved to be a potentially useful and non-invasive therapeutic strategy for post-infarction myocardial repair⁵⁶, and the influence of CXCR4 expression on migration, proliferation, differentiation, and paracrine effects of MSCs was examined in vitro^57,58. Overexpression of CXCR4 leading to enhanced mobilization in vivo and implantation of MSCs in ischemic areas⁵⁷ may improve the homing ability and colonization capacity of umbilical cord blood stem cells for neurological regeneration.

Secretion of Trophic Factors

There is a general consensus that after homing, stem cells secrete neurotrophic factors, cytokines, immunomodulatory factors, and angiogenic factors in a paracrine manner; these are proposed to be the most important therapeutic mechanisms. These factors influence target cells to modulate inflammation/apoptosis, activating progenitor cell proliferation and tissue repair to provide a good environment for cell survival, which is more direct and rapid after transplantation. The paracrine activity of stem cells is generally considered to comprise two main pathways: soluble factors and extracellular vesicles (EVs) (including exosomes).

Angulski et al. profiled the protein content of CD133⁺-EVs isolated from UCB compared with BM-derived hMSCs for better understanding of the functions in each vesicle type and delineating the appropriate use of each EV in therapeutic procedures⁵⁹. For protein content, expanded CD133+-EVs might be better inducers or modulators of angiogenesis (e.g. von Willebrand factor) than hMSC-EVs, while hMSC-EVs might more efficiently induce/modulate differentiation (e.g. signal transducer and activator of transcription (STAT1)), phagocytosis, and innate immune responses (e.g. lactotransferrin (LTF) and complement component 1 binding protein (C1QBP)) of the target cells. However, typical actors of T-cell response inhibition or promoters of regulatory T-cell response in hMSC-EVs could not be found. Depending on the purpose of treatment, cord blood may be favored, since it is a more convenient extraction mixture containing MNC-EVs and MSC-EVs.

Neurotrophic Factors and Cytokines through EVs and in Soluble Molecules

The different types of EVs may implement regenerative functions directly through vesicle protein, miRNAs, or even trophic factors⁶⁰. MSCs secrete EVs, which include exosomes and microvesicles, derived from the endosomal compartment, an isomeric mixture of microparticles (endoplasts), or directly from cytoplasmic membrane, resembling a saccular organelle-like structure. MSC-EVs have also been confirmed to bring about similar biological effects to cure various preclinical disease (including kidney, heart, and even brain injury models or patients^61,62). Ophelders et al. investigated the protective effects and axonal growth of MSC-EVs in a preclinical model of preterm HIE brain injury in ovine fetuses by intravenous administration in utero. The results suggested that administration of EVs, rather than intact MSCs, is sufficient to exert effects and avoids potential concerns because the EVs lack their own metabolism and are hardly influenced by the environment in vivo⁶³. Zhang et al. reported that native MSC-exosomes promoted axonal growth, and their designed tailored MSCs-exosomes could further boost this effect. Their designed tailored MSC-exosomes carried elevated miRNA-17-92 clusters relative to native MSC-exosomes, providing a potential therapeutic strategy to enhance axonal growth²⁶.

Soluble molecules are secreted from stem cells after fusion of secretory granules through the plasma membrane. Their effects are mediated via membrane receptor interaction with recipient cells⁶⁰. Among them, granulocyte colony-stimulating factor (GCSF), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) may be suitable for adjuvant stem cell therapy. GCSF and granulocyte-macrophage colony-stimulating factor (GM-CSF) are hematopoietic hormones that promote the proliferation and differentiation of neutrophils⁶⁴. The drug analogs of GCSF, filgrastim and lenograstim, are mainly used for the treatment of neutropenia and allogeneic or autologous BM transplant hypoplasia after restorative treatment⁶⁵. These hematopoietic growth factors and their receptors were discovered 30 years ago and are highly expressed in neurons following brain injury. Other reports have suggested that GCSF may be a candidate for stem cell transplantation as a novel neurotrophic factor^66,67. There is evidence that GCSF activates proteins of the Stat family and the PI3-K/Akt pathway to protect neurons from the intracellular pathways of hematopoietic cells⁶⁸. In a randomized, double-blind, crossover study in South Korea, researchers evaluated the potential of nerve regeneration in intraventricular GCSF after infusion of mobilized peripheral blood mononuclear cells (mPBMCs) in a clinical trial for CP (trial registration: ClinicalTrials.gov, NCT02983708). Apart from demonstrating the potential for neural regeneration of intravenous GCSF followed by mPBMC reinfusion, they also concluded that the observed improvement in neurodevelopment may be due to GCSF alone, rather than the effect from reperfused mPBMCs. Future studies should examine the benefit of reinfusion of mPBMCs alone at higher concentrations without GCSF⁶⁹. In the JAK / Stat pathways, the erythropoietin (EPO) gene shows a highly similar expression profile between neural and hematopoietic stem cells. EPO receptors are cytokine-type transmembrane proteins. EPO receptors that have neuroprotective effects are heterodimers and constitute common members of the receptors for cytokines IL5, IL3, and GM-CSF⁷⁰. In the PI3K-Akt signaling pathway, Akt-mediated activation of anti-apoptotic neurons is crucial. GCSF activates the PI3K-Akt signaling pathway, and EPO is a major contributor to neuroprotection via this pathway. GCSF and EPO are also involved in ERK1/2 kinase pathways, and both their receptors lack intrinsic tyrosine kinase activity^71
–73.

The roles of BDNF and GDNF in regulating neuronal development, regeneration, and survival have been repeatedly confirmed. It has now been found that adding BDNF can differentiate over-expressed hUCB-MSCs into an increased number of neuron-like cells, and can upregulate neuronal phenotypic marker expression.

Although the formation of functional nerve cells and the establishment of axonal connections are among the goals of cell therapy for CP, administration of neurotrophic factors alone may support the function of existing cells and build a good growth environment for newborn nerve cells and axons.

Angiogenic Factors through EVs and in Soluble Molecules

Mononuclear cell-derived (CD133⁺ cell) EVs have been tested in various disease models, including neurological diseases.^74,75 Expanded CD133⁺ or endothelial-like cells (EPC)-EVs containing vascular endothelial growth factor (VEGF) and angiogenin appear to act primarily through stimulation and modulation of angiogenesis⁷⁶. VEGF served as an ideal candidate additive, but its subtypes differ greatly in generating blood vessels. Beerens et al. reported that, unlike mouse ESCs or iPSCs, culturing multipotent adult progenitor cells with VEGF-A produced a mixture of arterial, venous, and lymphatic endothelial cells. Addition of VEGF-C did not have this effect⁷⁷. Angiogenin may be a key factor, since angiogenin signaling attenuated the positive effects of the EPC secretome. In vivo, treatment with the EPC secretome increased vascular density, myelin, and mature oligodendrocytes in white matter, and ameliorated cognitive function in a mouse model of hypoperfusion⁷⁸.

Immunoregulation and Neuroprotection

UCB mononuclear/whole blood cells in the perinatal ischemic and hypoxic brain model can reduce the inflammatory response to treat injury²¹. To evaluate whether transplanted cells relieve neuroinflammation, there are two indicators: (1) reduce the infiltration of CD4⁺ T cells into the brain; and (2) reduce microglial activation. McDonald and colleagues confirmed that all UCB cell types except EPCs have CNS immunoregulatory capacity. Tregs and monocytes are present in the normal body at a considerable level, and are indispensable in the regulation of peripheral and central immune responses²¹.

Some specific subsets of Tregs suppress T-cell proliferation. After transplantation, IL-4-produced Th2 cells and Tregs occurred frequently both within the brain and in peripheral tissues. In general, it is beneficial to coordinate an immunomodulatory macrophage response, reduce microglial activation, and to protect against tissue injury⁷⁹. However, McDonald et al. only found a significant increase in the proportion of IL-4-producing Th2 cells after UCB treatment alone, without an increase in the number of Tregs²¹. Whether the uniqueness of this upregulation of inflammatory factors can serve as an entry point for repairing neural tissue from the peripheral pathway remains to be explored. MDSCs have the potential to be used as novel seed cells due to their comprehensive anti-inflammatory effects^80,81 (modulating innate and adaptive immune responses by promoting T lymphocyte apoptosis). However, it is striking that monocytes did not reduce microglial activation but instead activated the neuroinflammatory response and assisted in gathering T lymphocytes in the brain. McDonald et al. proposed that MDSCs may not be the only CD14⁺ monocyte in the trial, and future experiments need to study more specific surface markers for MDSCs.

In addition, the aforementioned secretory cytokines and immune factors also play a role in immune regulation. MCP-1, interleukin (IL)-6, IL-8, and IL-10 secretion were also observed in UCB. MCP-1 in astrocytes has been reported to be critical for inflammation development. After UCB treatment for 48 h in both hippocampal and striatal ischemic tissues, the ischemic extracts demonstrated that growth-regulated oncogene/CINC-1 (GRO/CINC-1, the rat equivalent of human IL-8) and MCP-1 were expressed in a time-dependent pattern. TNF-α-induced astrocytes have been associated with a variety of pathological situations. MCP-1 regulates TNF-α through the activated protein kinase signaling (AMPK) pathway⁸¹.

HSCs have long been considered to have neuroprotective potential by stimulating and participating in angiogenesis^82
-84, and hMSC-EVs containing immunomodulatory factors were proved to act in several processes in the modulation of the immune response (developmental, maturation, and induction process)⁸⁵. MSC-EV administration alone not only improves brain function but also avoids the development of intracerebral inflammation⁶³. Studies have shown that MSC-EVs can improve inflammation-induced neuronal degeneration, reduce microglial proliferation, and prevent reactive astrocyte proliferation. Short-term myelin deficiency and long-term microstructural abnormalities in white matter can be improved by administration of MSC-EVs, and is an active research direction⁸⁶. Different cells release different inflammatory chemokines that mediate the innate and adaptive immune systems. Currently, 50 chemokines and 20 different chemokine receptors have been discovered⁸⁷.

It must be pointed out that the three mechanisms of action are inextricably linked during the course of cell therapy. The homing cells colonize the injured site and participate in the formation of neurons, glial cells, axons, and blood vessels surrounding tissues. The homing cells release neurotrophic factors in a paracrine manner to promote the regeneration of neurons and blood vessels and release inflammatory and anti-inflammatory factors to protect the growth environment. Early inflammation is beneficial, and Treg regulation is essential for regeneration. The majority of non-homing cells also release large amounts of soluble molecules or transmit angiogenic factors, cytokines, or even miRNAs in the form of EV-cells to promote regeneration. More tissue regeneration magnifies the effect on repair damage (Fig. 1). In order to elaborate on the role of each cell or factor in UCB and to find suitable complementary treatment options, we describe the three mechanisms in isolation.

Figure 1.

Therapeutic effects and related mechanisms of major cellular components of cord blood on cerebral palsy. Five common components were isolated from collected cord blood (HSPs, MSCs, EPCs, Tregs, MDSCs) and their therapeutic effects are achieved, respectively, through the mechanisms homing and neuroregeneration, trophic factor secretion, and immunoregulation and neuroprotection. The three treatment mechanisms are also interrelated.

Outcomes and Outlook

Clinical Trials

A total of 18 clinical trials for CP treatment using UCB have been registered from clinicaltrials.gov since June 25, 2018 (Table 2) (enrollment data not uploaded in NCT01486732 and NCT03203941), including 10 completed studies (with the exclusion of HIE). However, when McDonald et al. published their review (September 2017), there were only 11 clinical trials for CP (only four completed). More clinical trials are now being designed and completed, indicating that UCB is a valid choice for CP.

Table 2.

Clinical Trials Using Umbilical Cord Blood for the Treatment of Cerebral Palsy. Information Obtained from ClinicalTrials.gov .

NCT Number	Title	Status	Interventions	Study type	Outcome measure	Population	Research purposes
01639404	Umbilical Cord Blood Therapy for Children With Cerebral Palsy	Complete	UCB+ Rehabilitation	Single Group; Open Label	Motor Performance; Standardized Gross Motor Function; Cognitive; VisualPerception Test;	Enrollment:17(6M-12Y)	Neuroregeneration; Trophic secretion;
01528436	Umbilical Cord Blood Therapy for Cerebral Palsy	Complete	UCB+ Rehabilitation	Randomized; Parallel; Quadruple	Gross Motor Function; Cognitive; Visual Perception Test; Muscle Strength; Brain Glucose Metabolism;	Enrollment:37(6M-20Y)	Neuroregeneration; Trophic secretion;
01193660	Allogenic Umbilical Cord Blood and Erythropoietin Combination Therapy for Cerebral Palsy	Complete	UCB+EPO+R/UCB/EPO	Randomized; Parallel; Quadruple	Gross Motor Function; Cognitive; MRI; Brain Glucose Metabolism; 18F-FDG; Muscle Strength	Enrollment:105(10M-10Y)	Neuroregeneration; Trophic secretion;
02599207	Assessment of the Safety of Allogeneic Umbilical Cord Blood Infusions in Children With Cerebral Palsy	Active, not recruiting	Sibling UCB	Non-Randomized;Open Label	adverse events; gross motor function	Enrollment:15(1Y-6Y)	Neuroregeneration; Trophic secretion; Neuroprotection
02025972	Allogeneic Umbilical Cord Blood Therapy in Children With CP	Complete	Allogeneic UCB	Single Group Assignment; Open Label;	Cytokine analysis; Gross Motor Function; Cognitive;	Enrollment:10(up to 15Y)	Neuroregeneration; Trophic secretion; Neuroprotection
01072370	Safety and Effectiveness of Cord Blood Stem Cell Infusion for the Treatment of Cerebral Palsy in Children	Recruiting	Autologous UCB	Randomized; Crossover Assignment;Blind	Safety, follow-up over one year with clinical and laboratory evaluations; efficacy, Gross Motor Function	Enrollment:40(1Y-12Y)	Neuroregeneration; Trophic secretion;
01988584	Safety and Effectiveness of Banked Cord Blood or Bone Morrow Stem Cells in Children With Cerebral Palsy (CP)	Complete	Autologous SC/ Saline	Randomized; Crossover Assignment; Triple	SafetyLate functional outcome	Enrollment:20(2Y-10Y)	Neuroregeneration; Trophic secretion;Neuroprotection
03473301	A Study of UCB and MSCs in Children With CP: ACCeNT-CP	Not yet recruiting	Allogeneic UCB;MSC	Randomized; Parallel; Single	GMFM-66 scoreAdverse Event	Enrollment:90(24M-60 M)	Neuroregeneration; Trophic secretion;
01147653	A Randomized Study of Autologous Umbilical Cord Blood Reinfusion in Children With Cerebral Palsy	Complete	Autologous UCB; Placebo	Randomized; Crossover Assignment; Quadruple	(GMFM-66) Score; Peabody Gross Motor Quotient; CP-QOL Score; MRI;	Enrollment:63(12M-6Y)	Neuroregeneration; Trophic secretion;
02866331	GCSF and Autologous Cord Blood Infusion in Cerebral Palsy	Recruiting	GCSF; CB; Placebo	Randomized; Parallel; Quadruple;	Safety; efficacy;	Enrollment:88(2Y-10Y)	Neuroregeneration; Trophic secretion; Neuroprotection
03130816	Mechanism of Allogeneic UCB Therapy in Cerebral Palsy	Recruiting	Allogeneic CB	Single; Open Label	GMFM; mRNA assay; GMPM	Enrollment:90(10M-20Y)	Neuroregeneration; Trophic secretion; Neuroprotection
03087110	Stem Cells in Umbilical Blood Infusion for CP	Active, not recruiting	sibling donor CB	Single; Open Label;	gross motor function; cognitive;	Enrollment:12(1Y-16Y)	Neuroregeneration; Trophic secretion;
01991145	Allogeneic UCB Therapy With EPO in Children With CP	Complete	UCB+R/EPO	Randomized; Parallel; Quadruple;	Gross Motor Function; Cognitive;	Enrollment:92(10M-6Y)	Neuroregeneration; Trophic secretion;
02236065	Combination Therapy of Cord Blood and GCSF for Patients With Brain Injury or Neurodegenerative Disorders	Complete	UCB+ GCSF	Single; Open Label;	Berg Balance Scale; Gross Motor Function; ALSFRS-R; UPDRS	Enrollment:10(19Y-75Y)	Neuroregeneration; Trophic secretion;
01506258	Autologous Stem Cells in Newborns With Oxygen Deprivation	Unknown status	SC+ Observation	Non-Randomized; Parallel; Open Label; Prevention	Effects;	Enrollment:20(37W-42 W)	Neuroregeneration; Trophic secretion;
01929434	Efficacy of Stem Cell Transplantation Compared to Rehabilitation Treatment of Patients With Cerebral Paralysis	Complete	SC+ rehabilitation	Randomized; Parallel; Single	Gross Motor Function; Routine Blood Test	Enrollment:300(1Y-14Y)	Neuroregeneration; Trophic secretion;
01147653	A Randomized Study of autologous Umbilical Cord Blood Reinfusion in children with cerebral palsy	Complete	Autologous UCBs	Randomized, Double-blind; Crossover Assignment	Improvement of standardized measures of neurodevelopmental function at 2 years	Enrollment:63(12M-6Y)	Neuroregeneration; Trophic secretion;

Nevertheless, the conclusions of ongoing and completed trials are positive but still limited. One of the reasons is that most of the trials are still open-label, single-group studies. This phenomenon reflects the urgent feelings of parents and research designers themselves, who want to obtain curative effects in a short time. Because of the long course of treatment, it may be difficult for some of the children in the control groups to have sufficient time and funds to proceed. Another reason is that there are too many variables to control. Both McDonald et al.²⁵ and Novak et al.²² mention in their papers that the sample size was small. However, we believe that the reason for this “small samples impression” is that the common conditions of the samples are too few to be informative (too many variables designed in the study).

Treatment Effects and Adverse Reactions

In Rizk et al.’s article³⁴, 12 of the UCB therapy studies are for patients with CP. The results in nine studies were considered to be probably effective (patients 201/276) and four of these studies have control groups. Sixty-seven patients had adverse reactions: fever (20/67), nausea and vomiting (13/67), rash (4/67), seizure (3/67), and others (4/67). With regard to cell types, 31 studies are for mononuclear cells, 20 studies for MSCs²⁶, and 11 for autologous cells.

NCT01193660, randomized and parallel assignment, enrolled 105 participants from age 10 months to 10 years for a 6-month observation period. Some 31/35 CP patients joined a cell therapy group (total nucleated UCB cells > 3×10⁷/kg intravenously and erythropoietin, twice a week for 4 weeks with the dosage of 500 IU/kg twice intravenously and 250 IU/kg six times subcutaneously, and active rehabilitation). 33/36 and 32/34 patients were divided into erythropoietin and rehabilitation group and rehabilitation-only group. The study demonstrated that cell therapy improved children’s functions in most outcome measures (motor performance, gross motor function, cognitive neurodevelopment outcome, motor neurodevelopment outcome; comparison of changes in brain glucose metabolism using by brain 18F-FDG PET, functional independence in daily activities, muscle strength, and hand function). These were no differences in serious adverse events (pneumonia, seizures, influenza, urinary tract infection, death) rates (3/35 in UCB with erythropoietin and rehabilitation group, 3/36 in erythropoietin and rehabilitation group, 3/34 in rehabilitation-only group)⁸⁸. NCT01147653, a double-blind, placebo-controlled, crossover study of a single intravenous infusion of 1–5×10⁷ total nucleated cells per kilogram of autologous cord blood (ACB) for children with CP aged 1–6 years enrolled 63 participants. In an analysis 1 year post-ACB treatment, those who received doses ≥2×10⁷/kg demonstrated that appropriately dosed ACB infusion improves brain connectivity and gross motor function (significantly increases in Gross Motor Function Measure-66 (GMFM-66) scores, Peabody Developmental Motor Scales-2 Gross Motor Quotient scores and normalized brain connectivity)⁸⁹. It is noteworthy that the number of gastrointestinal disorders (2/63, 3.17%) in the trial was much less than that in NCT01193660 (27/35, 77.14%), but the number of children with respiratory-related infections (9/63, 14.28%) was far higher than the control group (2/63, 3.17%).

Collectively, these results lead to several conclusions. UCB is one of the most used cell types in clinical trials for CP with reliable safety and efficacy. Some 72.8% of patients with CP benefit from UCB-related cell therapy²⁵. However, with the exception of NCT03473301 being recruited, no independent controlled trial results have been published for each component in UCB so far. The general consensus of administration time is “the sooner the better”⁹⁰. Before the UCB test, a dose safety test must be performed^22,23. In a preclinical animal study, after the first 24 hours of initial insult, UCB mononuclear cell therapy as an early intervention showed a greater benefit in an HIE model²³. Early UCB intervention mainly exerted immunoregulatory and neuroprotective effects. Mononuclear cells seem to play a major role. The mechanism of neuroregeneration produces effects long (6 months or longer) after injury. Common adverse reactions are fever, rash, etc. At present, the efficacy and safety of autologous UCB are superior to that of allogeneic UCB. The different medicines and cell types have shown beneficial effects in clinical studies, but combination strategies may be the future of neural regeneration⁹¹.

Potential Cell Sources and Dose

In the current 18 trials, there are six types of tests using different sources (UCB+ Rehabilitation; UCB+EPO; Autologous UCB; Allogeneic (sibling or otherwise) UCB; GCSF) and three different doses (more than 10 M/kg body weight; more than 30 M/kg body weight; not mentioned). It is generally believed that 10 M/kg body weight is a safe dose for intravenous administration. Intravenous administration of autologous umbilical cord blood cells (UCBCs) therapy may be the safest and most feasible because UCB has been used for hematopoietic stem cell transplantation for decades⁹². Allogeneic cells for CP research and trials are readily available, primarily from privately and publicly banked UCB units, and the treatment of non-invasive injuries is easily accepted.

The blood cell collection, separation, and storage of UCBCs should be regulated to prevent infection⁹³. Jantzie et al. suggested that although UCB-MNCs and stem cells are relatively easy to obtain, the number obtained from each infant in each batch is variable and heterogenous, rendering the assessment of efficacy inconsistent⁹⁴. Therefore, the exact mechanism and optimum content of each component of UCB still need to be explored.

Candidate Situations

There have been numerous trials involving various conditions and recruitment of both adults and children. The degree of cooperation between the candidates under 6 years of age for evaluation and treatment is very low. In terms of efficacy, the treatment results for younger children seem to be more robust. To date, only six trials had treatment groups of 0–6 years old. It may be beneficial for national research teams to demonstrate cooperation, share results, and standardize testing standards.

Jantzie et al. claim that preterm babies may not be the best candidates for autologous stem cell transplants, as the collection volumes are proportional to gestational age⁹⁴. McDonald et al. proposed that each individual UCB unit has different proportions and changes throughout gestation²⁷, meaning that preterm UCB has different cell contents compared with that of term UCB⁹⁵.

Optimal Administration Route

Currently reported routes of administration are intraventricular, intrathecal, intranasal, intramuscular, intra-arterial, or intravenous^96
–98. Intraventricular and intrathecal injections are theoretically straightforward but invasive, in which the risks are unacceptable to children. Common complications include meningeal irritation such as nausea and vomiting, intraventricular hemorrhage, and subarachnoid hemorrhage.

The intravenous route is the most commonly used non-invasive protocol. Tracer methods show that a significant number of cells circulating through the system are colonized in the lungs^99,100. The most serious adverse effect of intravenous and arterial administration is pulmonary embolism, which is related to fast administration or excessive dose. Systemic pathways have the potential to modulate inflammatory responses, but a significant portion remains in other organs, and many do not cross the blood–brain barrier⁹⁷. Both Jantzie et al. and Kiasatdolatabadi et al. considered that local administration may be more feasible, and injection location even within the brain may be important^94,101.

Conclusions

We have reviewed the current mechanism of UCB-related stem cell types or components in CP-related therapy. UCB is beneficial for clinical use and its underlying mechanism has been studied, and meaningful progress made in both preclinical settings and clinical trials. However, several pressing issues for bringing stem cells into practice exist: (1) identifying the source of low-cost stem cells with high purity; (2) selecting the stem cell type with the best efficacy and safety; (3) in-depth study of the treatment mechanism of stem cells; (4) identifying administration route and dose; and (5) unifying effective evaluation criteria and follow-up work. Our review summarizes the features of active components in UCB and the therapeutic mechanism of action for treatment suggestions, but there needs to be much more research before its safe clinical use.

Footnotes

Acknowledgments

This work was funded by the National Natural Science Foundation of China (No.81271412, 81471308, 31500793), International S&T Cooperation Project of the Ministry of S&T of China (No.2010DFR30850), the Scientific Research Foundation for Returned Overseas Chinese Scholars, and the Doctoral Scientific Research Foundation of Liaoning Province (No. 201501158).

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

References

Rosenbaum

Paneth

Leviton

Goldstein

Bax

Damiano

Dan

Jacobsson

. A report: the definition and classification of cerebral palsy April 2006. Dev Med Child Neurol Suppl. 2007;109:8–14.

Obladen

. From “apparent death” to “birth asphyxia”: a history of blame. Pediatr Res. 2018;83(2):403–411.

Toyokawa

Maeda

Kobayashi

. Estimation of the number of children with cerebral palsy using nationwide health insurance claims data in Japan. Dev Med Child Neurol. 2017;59(3):317–321.

Novak

Hines

Goldsmith

Barclay

. Clinical prognostic messages from a systematic review on cerebral palsy. Pediatrics. 2012;130(5):e1285–e1312.

van Drimmelen-Krabbe

Bradley

Orgogozo

Sartorius

. The application of the international statistical classification of diseases to neurology: ICD-10 NA. J Neurol Sci. 1998;161(1):2–9.

Katz

. Life expectancy for children with cerebral palsy and mental retardation: implications for life care planning. NeuroRehabilitation. 2003;18(3):261–270.

Wang

Chen

Zhang

Guo

Hailey

. A preliminary study into the economic burden of cerebral palsy in China. Health Policy. 2008;87(2):223–234.

Sellier

Surman

Himmelmann

Andersen

Colver

Krageloh-Mann

De-la-Cruz

Cans

. Trends in prevalence of cerebral palsy in children born with a birthweight of 2,500 g or over in Europe from 1980 to 1998. Eur J Epidemiol. 2010;25(9):635–642.

Baumann

. Stem cells: translating hypertranscription in embryonic stem cells. Nat Rev Mol Cell Biol. 2018;19(4):209.

10.

Hacein-Bey-Abina

Von Kalle

Schmidt

McCormack

Wulffraat

Leboulch

Lim

Osborne

Pawliuk

Morillon

et al. LMO2-associated clonal T cell proliferation in two patients after gene therapy for SCID-X1. Science. 2003;302(5644):415–419.

11.

Friedenstein

Gorskaja

Kulagina

. Fibroblast precursors in normal and irradiated mouse hematopoietic organs. Exp Hematol. 1976;4(5):267–274.

12.

Kobolak

Dinnyes

Memic

Khademhosseini

Mobasheri

. Mesenchymal stem cells: identification, phenotypic characterization, biological properties and potential for regenerative medicine through biomaterial micro-engineering of their niche. Methods. 2016;99:62–68.

13.

Zhou

Yang

Tian

Jiao

Zheng

Wang

Guan

. Immunomodulatory effect of human umbilical cord Wharton’s jelly-derived mesenchymal stem cells on lymphocytes. Cell Immunol. 2011;272(1):33–38.

14.

Murata

Miyakoshi

Hatazoe

Miura

Tokunaga

Fujiki

Nakayama

Misumi

. Multipotency of equine mesenchymal stem cells derived from synovial fluid. Vet J. 2014;202(1):53–61.

15.

Ortved

Nixon

. Cell-based cartilage repair strategies in the horse. Vet J. 2016;208:1–12.

16.

Dominici

Le Blanc

Mueller

Slaper-Cortenbach

Marini

Krause

Deans

Keating

Prockop

Horwitz

. Minimal criteria for defining multipotent mesenchymal stromal cells. The international society for cellular therapy position statement. Cytotherapy. 2006;8(4):315–317.

17.

Stenderup

Justesen

Clausen

Kassem

. Aging is associated with decreased maximal life span and accelerated senescence of bone marrow stromal cells. Bone. 2003;33(6):919–926.

18.

Romanov

Tarakanov

Radaev

Dugina

Ryaskina

Darevskaya

Morozova

Khachatryan

Lebedev

Zotova

Burkova

et al. Human allogeneic AB0/Rh-identical umbilical cord blood cells in the treatment of juvenile patients with cerebral palsy. Cytotherapy. 2015;17(7):969–978.

19.

Broxmeyer

. Biology of cord blood cells and future prospects for enhanced clinical benefit. Cytotherapy. 2005;7(3):209–218.

20.

Phuc

Ngoc

Lam

Tam

Viet

Ngoc

. Isolation of three important types of stem cells from the same samples of banked umbilical cord blood. Cell Tissue Bank. 2012;13(2):341–351.

21.

McDonald

Penny

Paton

MCB

Sutherland

Nekkanti

Yawno

Castillo-Melendez

Fahey

Jones

Jenkin

Miller

. Effects of umbilical cord blood cells, and subtypes, to reduce neuroinflammation following perinatal hypoxic-ischemic brain injury. J Neuroinflammation. 2018;15(1):47.

22.

Novak

Walker

Hunt

Wallace

Fahey

Badawi

. Concise review: stem cell interventions for people with cerebral palsy: systematic review with meta-analysis. Stem Cells Transl Med. 2016;5(8):1014–1025.

23.

Yawno

Sutherland

Loose

Nitsos

Bischof

Castillo-Melendez

McDonald

Wong

Jenkin

Miller

. Preterm white matter brain injury is prevented by early administration of umbilical cord blood cells. Exp Neurol. 2016;283(Pt A):179–187.

24.

Aridas

McDonald

Paton

Yawno

Sutherland

Nitsos

Pham

Ditchfield

Fahey

Wong

Malhotra

et al. Cord blood mononuclear cells prevent neuronal apoptosis in response to perinatal asphyxia in the newborn lamb. J Physiol. 2016;594(5):1421–1435.

25.

McDonald

Fahey

Jenkin

Miller

. Umbilical cord blood cells for treatment of cerebral palsy; timing and treatment options. Pediatr Res. 2018;83(1–2):333–344.

26.

Zhang

Chopp

Liu

Katakowski

Wang

Tian

Zhang

. Exosomes derived from mesenchymal stromal cells promote axonal growth of cortical neurons. Mol Neurobiol. 2017;54(4):2659–2673.

27.

Lee

Park

Kim

Jekarl

Choi

Lee

Kim

Park

. The effect of fibroblast growth factor on distinct differentiation potential of cord blood-derived unrestricted somatic stem cells and Wharton’s jelly-derived mesenchymal stem/stromal cells. Cytotherapy. 2015;17(12):1723–1731.

28.

Harris

. Cord blood stem cells: a review of potential neurological applications. Stem Cell Rev. 2008;4(4):269–274.

29.

Lee

Yoon

Kang

Kim

Kang

. Effect of subcutaneous treatment with human umbilical cord blood-derived multipotent stem cells on peripheral neuropathic pain in rats. Korean J Physiol Pharmacol. 2017;21(2):153–160.

30.

Chen

Wang

Chen

Chang

Lin

Chang

Chio

. Umbilical cord blood-derived CD34(+) cells improve outcomes of traumatic brain injury in rats by stimulating angiogenesis and neurogenesis. Cell Transplant. 2014;23(8):959–979.

31.

Rieber

Gille

Köstlin

Schäfer

Spring

Ost

Spieles

Kugel

Pfeiffer

Heininger

Alkhaled

et al. Neutrophilic myeloid-derived suppressor cells in cord blood modulate innate and adaptive immune responses. Clin Exp Immunol. 2013;174(1):45–52.

32.

Shang

Zhang

. Comparison of the efficacy of cord blood mononuclear cells (MNCs) and CD34+ cells for the treatment of neonatal mice with cerebral palsy. Cell Biochem Biophys. 2014;70(3):1539–1544.

33.

Kalaszczynska

Ferdyn

. Wharton’s jelly derived mesenchymal stem cells: future of regenerative medicine? Recent findings and clinical significance. Biomed Res Int. 2015;2015:430847.

34.

Rizk

Aziz

Shorr

Allan

. Cell-based therapy using umbilical cord blood for novel indications in regenerative therapy and immune modulation: an updated systematic scoping review of the literature. Biol Blood Marrow Transplant. 2017;23(10):1607–1613.

35.

Forraz

McGuckin

. The umbilical cord: a rich and ethical stem cell source to advance regenerative medicine. Cell Prolif. 2011;44(suppl 1):60–69.

36.

Matsumoto

Matthews

. A need for renewed and cohesive US policy on cord blood banking. Stem Cell Rev. 2015;11(6):789–797.

37.

Fan

Chi

Cheng

Juan

Chiang

Lin

Harn

. Current proceedings of cerebral palsy. Cell Transplant. 2015;24(3):471–485.

38.

Jensen

. Autologous cord blood therapy for infantile cerebral palsy: from bench to bedside. Obstet Gynecol Int. 2014;2014:976321.

39.

Han

Craig

. Research using autologous cord blood - time for a policy change. Med J Aust. 2013;199(4):288–299.

40.

Lee

. Implication of cord blood for cell-based therapy in refractory childhood diseases. Int J Stem Cells. 2010;3(1):22–28.

41.

Chen

Sanberg

Wang

Willing

Sanchez-Ramos

Chopp

. Intravenous administration of human umbilical cord blood reduces behavioral deficits after stroke in rats. Stroke. 2001;32(11):2682–8.

42.

Sanberg

Mahmood

Wang

Sanchez-Ramos

Chopp

. Intravenous administration of human umbilical cord blood reduces neurological deficit in the rat after traumatic brain injury. Cell Transplant. 2002;11(3):275–281.

43.

Hall

Guyer

Leonardo

Ajmo

Jr Collier

Willing

Pennypacker

. Human umbilical cord blood cells directly suppress ischemic oligodendrocyte cell death. J Neurosci Res. 2009;87(2):333–341.

44.

Ashrafi

Zali

Pakdaman

Behnam

Ahmadi

Harandi

Oraee-Yazdani

. A review on stem cell therapy in cerebral palsy with a focus on motor function improvement. 2018; In Press(In Press).

45.

Liu

Zhuo

Tan

Xia

Zhuo

Deng

Gao

. Ultrasound-targeted microbubble destruction improves the migration and homing of mesenchymal stem cells after myocardial infarction by upregulating SDF-1/CXCR4: a pilot study. Stem Cells Int. 2015;2015:691310.

46.

Guo

Jin

. Effects of electroacupuncture combined with stem cell transplantation on anal sphincter injury-induced faecal incontinence in a rat model. Acupunct Med. 2018;36(4):254–260.

47.

Liu

Pan

Liang

Huang

. HGF/c-Met signaling mediated mesenchymal stem cell-induced liver recovery in intestinal ischemia reperfusion model. Int J Med Sci. 2014;11(6):626–633.

48.

Yagi

Soto-Gutierrez

Parekkadan

Kitagawa

Tompkins

Kobayashi

Yarmush

. Mesenchymal stem cells: mechanisms of immunomodulation and homing. Cell Transplant. 2010;19(6):667–679.

49.

Rahimzadeh

Mirakabad

Movassaghpour

Shamsasenjan

Kariminekoo

Talebi

Shekari

Zeighamian

Ghalhar

Akbarzadeh

. Biotechnological and biomedical applications of mesenchymal stem cells as a therapeutic system. Artif Cells Nanomed Biotechnol. 2016;44(2):559–570.

50.

Wynn

Hart

Corradi-Perini

O’Neill

Evans

Wraith

Fairbairn

Bellantuono

. A small proportion of mesenchymal stem cells strongly expresses functionally active CXCR4 receptor capable of promoting migration to bone marrow. Blood. 2004;104(9):2643–2645.

51.

Bhakta

Hong

Koc

. The surface adhesion molecule CXCR4 stimulates mesenchymal stem cell migration to stromal cell-derived factor-1 in vitro but does not decrease apoptosis under serum deprivation. Cardiovasc Revasc Med 2006;7(1):19–24.

52.

Wang

Deng

Zhou

. SDF-1alpha/CXCR4-mediated migration of systemically transplanted bone marrow stromal cells towards ischemic brain lesion in a rat model. Brain Res. 2008;1195:104–112.

53.

Rosenkranz

Kumbruch

Lebermann

Marschner

Jensen

Dermietzel

Meier

. The chemokine SDF-1/CXCL12 contributes to the ‘homing’ of umbilical cord blood cells to a hypoxic-ischemic lesion in the rat brain. J Neurosci Res. 2010;88(6):1223–1233.

54.

Dong

Shang

Niu

Luo

Yang

Meng

Yin

Zhang

Zhao

Lin

. The distribution of transplanted umbilical cord mesenchymal stem cells in large blood vessel of experimental design with traumatic brain injury. J Craniofac Surg. 2017;28(6):1615–1619.

55.

Kim

Hematti

. Mesenchymal stem cell-educated macrophages: a novel type of alternatively activated macrophages. Exp Hematol. 2009;37(12):1445–1453.

56.

Cheng

Zhou

Jia

Zhang

Liu

Ward

Melo

Kong

. Targeted migration of mesenchymal stem cells modified with CXCR4 gene to infarcted myocardium improves cardiac performance. Mol Ther. 2008;16(3):571–579.

57.

Zhang

Fan

Zhou

Zhao

Pasha

Zhu

Ashraf

Wang

. Over-expression of CXCR4 on mesenchymal stem cells augments myoangiogenesis in the infarcted myocardium. J Mol Cell Cardiol. 2008;44(2):281–292.

58.

Yang

Zhang

Wang

Gao

Yang

Wen

. CXCR4 receptor overexpression in mesenchymal stem cells facilitates treatment of acute lung injury in rats. J Biol Chem. 2015;290(4):1994–2006.

59.

Angulski

Capriglione

Batista

Marcon

Senegaglia

Stimamiglio

Correa

. The protein content of extracellular vesicles derived from expanded human umbilical cord blood-derived CD133(+) and human bone marrow-derived mesenchymal stem cells partially explains why both sources are advantageous for regenerative medicine. Stem Cell Rev. 2017;13(2):244–257.

60.

Bruno

Collino

Tetta

Camussi

. Dissecting paracrine effectors for mesenchymal stem cells. Adv Biochem Eng Biotechnol. 2013;129:137–152.

61.

Bruno

Grange

Deregibus

Calogero

Saviozzi

Collino

Morando

Busca

Falda

Bussolati

Tetta

et al. Mesenchymal stem cell-derived microvesicles protect against acute tubular injury. J Am Soc Nephrol. 2009;20(5):1053–1067.

62.

Doeppner

Herz

Gorgens

Schlechter

Ludwig

Radtke

de Miroschedji

Horn

Giebel

Hermann

. Extracellular vesicles improve post-stroke neuroregeneration and prevent postischemic immunosuppression. Stem Cells Transl Med. 2015;4(10):1131–1143.

63.

Ophelders

Wolfs

Jellema

Zwanenburg

Andriessen

Delhaas

Ludwig

Radtke

Peters

Janssen

Giebel

et al. Mesenchymal stromal cell-derived extracellular vesicles protect the fetal brain after hypoxia-ischemia. Stem Cells Transl Med. 2016;5(6):754–763.

64.

Lieschke

Burgess

. Granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor (1). N Engl J Med. 1992;327(1):28–35.

65.

Jones

Bolyard

Dale

. Quality of life of patients with severe chronic neutropenia receiving long-term treatment with granulocyte colony-stimulating factor. Jama. 1993;270(9):1132–1133.

66.

Schabitz

Kollmar

Schwaninger

Juettler

Bardutzky

Scholzke

Sommer

Schwab

. Neuroprotective effect of granulocyte colony-stimulating factor after focal cerebral ischemia. Stroke. 2003;34(3):745–751.

67.

Schneider

Krüger

Steigleder

Weber

Pitzer

Laage

Aronowski

Maurer

Gassler

Mier

Hasselblatt

et al. The hematopoietic factor G-CSF is a neuronal ligand that counteracts programmed cell death and drives neurogenesis. J Clin Invest. 2005;115(8):2083–2098.

68.

Liao

Yeh

Chao

Lee

Hung

. An early granulocyte colony-stimulating factor treatment attenuates neuropathic pain through activation of mu opioid receptors on the injured nerve. Sci Rep. 2016;6:25490.

69.

Rah

Lee

Moon

Jun

Kang

Koh

Eom

Lee

Kim

Choi

et al. Neuroregenerative potential of intravenous G-CSF and autologous peripheral blood stem cells in children with cerebral palsy: a randomized, double-blind, cross-over study. J Transl Med. 2017;15(1):16.

70.

Brines

Grasso

Fiordaliso

Sfacteria

Ghezzi

Fratelli

Latini

Xie

Smart

Su-Rick

Pobre

et al. Erythropoietin mediates tissue protection through an erythropoietin and common beta-subunit heteroreceptor. Proc Natl Acad Sci U S A. 2004;101(41):14907–14912.

71.

Ruscher

Freyer

Karsch

Isaev

Megow

Sawitzki

Priller

Dirnagl

Meisel

. Erythropoietin is a paracrine mediator of ischemic tolerance in the brain: evidence from an in vitro model. J Neurosci. 2002;22(23):10291–10301.

72.

Sirén

Fratelli

Brines

Goemans

Casagrande

Lewczuk

Keenan

Gleiter

Pasquali

Capobianco

Mennini

et al. Erythropoietin prevents neuronal apoptosis after cerebral ischemia and metabolic stress. Proc Natl Acad Sci U S A. 2001;98(7):4044–4049.

73.

Digicaylioglu

Garden

Timberlake

Fletcher

Lipton

. Acute neuroprotective synergy of erythropoietin and insulin-like growth factor I. Proc Natl Acad Sci U S A. 2004;101(26):9855–9860.

74.

Xin

Buller

Katakowski

Zhang

Wang

Shang

Zhang

Chopp

. Exosome-mediated transfer of miR-133b from multipotent mesenchymal stromal cells to neural cells contributes to neurite outgrowth. Stem Cells. 2012;30(7):1556–1564.

75.

Xin

Liu

Wang

Shang

Cui

Zhang

Chopp

. MiR-133b promotes neural plasticity and functional recovery after treatment of stroke with multipotent mesenchymal stromal cells in rats via transfer of exosome-enriched extracellular particles. Stem Cells. 2013;31(12):2737–2746.

76.

Asahara

Murohara

Sullivan

Silver

van der Zee

Witzenbichler

Schatteman

Isner

. Isolation of putative progenitor endothelial cells for angiogenesis. Science. 1997;275(5302):964–967.

77.

Beerens

Aranguren

Hendrickx

Dheedene

Dresselaers

Himmelreich

Verfaillie

Luttun

. Multipotent Adult Progenitor Cells Support Lymphatic Regeneration at Multiple Anatomical Levels during Wound Healing and Lymphedema. Sci Rep. 2018;8(1):3852.

78.

Maki

Morancho

Martinez-San Segundo

Hayakawa

Takase

Liang

Gabriel-Salazar

Medina-Gutiérrez

Washida

Montaner

Lok

et al. Endothelial progenitor cell secretome and oligovascular repair in a mouse model of prolonged cerebral hypoperfusion. Stroke. 2018;49(4):1003–1010.

79.

Tan

Chan

Deane

McDonald

Bernard

Wallace

Lim

. Amnion cell-mediated immune modulation following bleomycin challenge: controlling the regulatory T cell response. Stem Cell Res Ther. 2015;6:8.

80.

Moline-Velazquez

Cuervo

Vila-Del Sol

Ortega

Clemente

de Castro

. Myeloid-derived suppressor cells limit the inflammation by promoting T lymphocyte apoptosis in the spinal cord of a murine model of multiple sclerosis. Brain Pathol. 2011;21(6):678–691.

81.

Qin

Qiao

Cheng

Wan

Liu

. Curcumin inhibits monocyte chemoattractant protein-1 expression in TNF-alpha induced astrocytes through AMPK pathway. Neurochem Res. 2018;43(4):775–784.

82.

Kim

Ahn

Sung

Park

Choi

Chang

Lee

Park

. Human umbilical cord blood-derived mesenchymal stem cell transplantation attenuates severe brain injury by permanent middle cerebral artery occlusion in newborn rats. Pediatr Res. 2012;72(3):277–284.

83.

Park

Sung

Ahn

Yoo

Sung

Choi

Chang

. Hypothermia augments neuroprotective activity of mesenchymal stem cells for neonatal hypoxic-ischemic encephalopathy. Plos One. 2015;10(3):e0120893.

84.

Tsuji

Taguchi

Ohshima

Kasahara

Sato

Tsuda

Otani

Yamahara

Ihara

Harada-Shiba

Ikeda

et al. Effects of intravenous administration of umbilical cord blood CD34(+) cells in a mouse model of neonatal stroke. Neuroscience. 2014;263:148–158.

85.

Chen

Armstrong

. Mesenchymal stem cells in immunoregulation. Immunol Cell Biol. 2006;84(5):413–421.

86.

Drommelschmidt

Serdar

Bendix

Herz

Bertling

Prager

Keller

Ludwig

Duhan

Radtke

de Miroschedji

et al. Mesenchymal stem cell-derived extracellular vesicles ameliorate inflammation-induced preterm brain injury. Brain Behav Immun. 2017;60:220–232.

87.

Shiwen

Abraham

Tsui

Baker

. Stromal-cell-derived factor-1 (SDF-1)/CXCL12 as potential target of therapeutic angiogenesis in critical leg ischaemia. Cardiol Res Pract. 2012;2012:143209.

88.

Min

Song

Kang

Ryu

Kang

Jang

Kim

et al. Umbilical cord blood therapy potentiated with erythropoietin for children with cerebral palsy: a double-blind, randomized, placebo-controlled trial. Stem Cells. 2013;31(3):581–591.

89.

Sun

Song

Case

Mikati

Gustafson

Simmons

Goldstein

Petry

McLaughlin

Waters-Pick

Chen

et al. Effect of autologous cord blood infusion on motor function and brain connectivity in young children with cerebral palsy: a randomized, placebo-controlled trial. Stem Cells Transl Med. 2017;6(12):2071–2078.

90.

Natarajan

Pappas

Shankaran

Kendrick

Das

Higgins

Laptook

Bell

Stoll

Newman

Hale

et al. Outcomes of extremely low birth weight infants with bronchopulmonary dysplasia: impact of the physiologic definition. Early Hum Dev. 2012;88(7):509–515.

91.

Alok

Geng

Sane

Kulkarni

. Clinical neurorestorative progresses in cerebral palsy. J Neurorestoratol. 2017;5:51–57.

92.

Bennet

Tan

Van den Heuij

Derrick

Groenendaal

van Bel

Juul

Back

Northington

Robertson

Mallard

et al. Cell therapy for neonatal hypoxia-ischemia and cerebral palsy. Ann Neurol. 2012;71(5):589–600.

93.

Nabetani

Shintaku

Hamazaki

. Future perspectives of cell therapy for neonatal hypoxic-ischemic encephalopathy. Pediatr Res. 2018;83(1–2):356–363.

94.

Jantzie

Scafidi

Robinson

. Stem cells and cell-based therapies for cerebral palsy: a call for rigor. Pediatr Res. 2018;83(1–2):345–355.

95.

Javed

Mead

Prater

Bessler

Foster

Case

Goebel

Yoder

Haneline

Ingram

. Endothelial colony forming cells and mesenchymal stem cells are enriched at different gestational ages in human umbilical cord blood. Pediatr Res. 2008;64(1):68–73.

96.

Shroff

Gupta

Barthakur

. Therapeutic potential of human embryonic stem cell transplantation in patients with cerebral palsy. J Transl Med. 2014;12:318.

97.

Shapira

Fainstein

Tsirlin

Stav

Volinsky

Moresi

Ben-Hur

Gorodetsky

. Placental stromal cell therapy for experimental autoimmune encephalomyelitis: the role of route of cell delivery. Stem Cells Transl Med. 2017;6(4):1286–1294.

98.

Donega

Nijboer

van Tilborg

Dijkhuizen

Kavelaars

Heijnen

. Intranasally administered mesenchymal stem cells promote a regenerative niche for repair of neonatal ischemic brain injury. Exp Neurol. 2014;261:53–64.

99.

Wagner

Henschler

. Fate of intravenously injected mesenchymal stem cells and significance for clinical application. Adv Biochem Eng Biotechnol. 2013;130:19–37.

100.

Park

Lee

Hwang

Choi

Hwang

Hyung

Chang

. Distribution of human umbilical cord blood-derived mesenchymal stem cells in the Alzheimer’s disease transgenic mouse after a single intravenous injection. Neuroreport. 2016;27(4):235–241.

101.

Kiasatdolatabadi

Lotfibakhshaiesh

Yazdankhah

Ebrahimi-Barough

Jafarabadi

Sadroddiny

. The role of stem cells in the treatment of cerebral palsy: a review. Mol Neurobiol. 2017;54(7):4963–4972.

A New Approach to Cerebral Palsy Treatment: Discussion of the Effective Components of Umbilical Cord Blood and its Mechanisms of Action

Abstract

Keywords

Introduction

Discussion

UCB Composition Selection and Treatment Mechanism

Enhancement of Neuroregeneration by Homing

Secretion of Trophic Factors

Neurotrophic Factors and Cytokines through EVs and in Soluble Molecules

Angiogenic Factors through EVs and in Soluble Molecules

Immunoregulation and Neuroprotection

Outcomes and Outlook

Clinical Trials

Treatment Effects and Adverse Reactions

Potential Cell Sources and Dose

Candidate Situations

Optimal Administration Route

Conclusions

Footnotes

Acknowledgments

Declaration of Conflicting Interests

Funding

References