Systemic Administration of Allogeneic Cord Blood Mononuclear Cells in Adults with Severe Acute Contusion Spinal Cord Injury: Phase I/IIa Pilot Clinical Study - Safety and Primary Efficacy Evaluation

The therapeutic role of SSEA3(+) human umbilical cord blood mononuclear cells in ischemic stroke model

Numerous evidences showed that human umbilical cord blood (UCB) mononuclear cells were a promising approach for the therapy of ischemic stroke(IS). The effect of stage-specific embryonic antigen 3 (SSEA3）positive subpopulation in UCB was not investigated in IS. In this study, we isolated SSEA3 positive cells from healthy UCB mononuclear cells, which comprised about 7.01% of the total UCB-mononuclear cells. Flow cytometry analysis revealed that SSEA3(+)UCB cells were almost positive for CD44 and CD45, and negative for CD73, CD90 and CD105. The expression of Oct3/4 in SSEA3(+)UCB cells were higher than that in UCB. SSEA3(+)UCB cells sorted by magnetic cell sorting were intravenously injected into the middle cerebral arterial occlusion(MCAO) rat model. Neurological score showed that SSEA3(+)UCB transplantation group exhibited significant improvements in the functional outcome of MCAO rats than UCB transplantation group. Nissl staining and microtubule association protein-2(MAP2) immunofluorescence staining showed that the SSEA3(+)UCB transplantation group decreased neuronal loss. SSEA3(+)UCB transplantation group reduced neuronal apoptosis, inhibited caspase3 expression, and decreased tumor necrosis factor α(TNF-α). These results indicate that SSEA3 positive cells are a novel subpopulation of UCB cells, which exhibit great potential for the treatment of ischemic stroke.

Current status and future perspectives on stem cell transplantation for spinal cord injury

BACKGROUND

Previous assessments of stem cell therapy for spinal cord injuries (SCI) have encountered challenges and constraints. Current research primarily emphasizes safety in early-phase clinical trials, while systematic reviews prioritize effectiveness, often overlooking safety and translational feasibility. This situation prompts inquiries regarding the readiness for clinical adoption.

AIM

To offer an up-to-date systematic literature review of clinical trial results con cerning stem cell therapy for SCI.

METHODS

A systematic search was conducted across major medical databases [PubMed, Embase, Reference Citation Analysis (RCA), and Cochrane Library] up to October 14, 2023. The search strategy utilized relevant Medical Subject Heading (MeSH) terms and keywords related to "spinal cord", "injury", "clinical trials", "stem cells", "functional outcomes", and "adverse events". Studies included in this review consisted of randomized controlled trials and non-randomized controlled trials reporting on the use of stem cell therapies for the treatment of SCI.

RESULTS

In a comprehensive review of 66 studies on stem cell therapies for SCI, 496 papers were initially identified, with 237 chosen for full-text analysis. Among them, 236 were deemed eligible after excluding 170 for various reasons. These studies encompassed 1086 patients with varying SCI levels, with cervical injuries being the most common (42.2%). Bone marrow stem cells were the predominant stem cell type used (71.1%), with various administration methods. Follow-up durations averaged around 84.4 months. The 32.7% of patients showed functional impro vement from American spinal injury association Impairment Scale (AIS) A to B, 40.8% from AIS A to C, 5.3% from AIS A to D, and 2.1% from AIS B to C. Sensory improvements were observed in 30.9% of patients. A relatively small number of adverse events were recorded, including fever (15.1%), headaches (4.3%), muscle tension (3.1%), and dizziness (2.6%), highlighting the potential for SCI recovery with stem cell therapy.

CONCLUSION

In the realm of SCI treatment, stem cell-based therapies show promise, but clinical trials reveal potential adverse events and limitations, underscoring the need for meticulous optimization of transplantation conditions and parameters, caution against swift clinical implementation, a deeper understanding of SCI pathophysiology, and addressing ethical, tumorigenicity, immunogenicity, and immunotoxicity concerns before gradual and careful adoption in clinical practice.

Therapeutic effect of umbilical cord blood cells on spinal cord injury

Spinal cord injury (SCI) is a nervous system disease characterized by sensory and motor dysfunction, axonal apoptosis, decreased vascular density, and inflammation. At present, surgical treatment, drug treatment, and cell therapy can be used. Surgical treatment can improve motor and independent function scores, and drug treatment can promote the recovery of neurons in the spinal cord, but only improve symptoms. Complete recovery of SCI has not yet been achieved. However, the differentiation of stem cells brings hope for the treatment of SCI. Umbilical cord blood cells (UCBs) are ethically readily available and can repair neuronal damage. However, it is still unclear how they can improve symptoms and repair nerve severity. In this paper, the role of UCBs in the treatment of SCI is described in detail from different aspects such as behavior, morphology, and molecular expression changes, so as to provide new ideas and theoretical directions for future research.

Molecular Mechanisms and Clinical Application of Multipotent Stem Cells for Spinal Cord Injury

Spinal Cord Injury (SCI) is a common neurological disorder with devastating psychical and psychosocial sequelae. The majority of patients after SCI suffer from permanent disability caused by motor dysfunction, impaired sensation, neuropathic pain, spasticity as well as urinary complications, and a small number of patients experience a complete recovery. Current standard treatment modalities of the SCI aim to prevent secondary injury and provide limited recovery of lost neurological functions. Stem Cell Therapy (SCT) represents an emerging treatment approach using the differentiation, paracrine, and self-renewal capabilities of stem cells to regenerate the injured spinal cord. To date, multipotent stem cells including mesenchymal stem cells (MSCs), neural stem cells (NSCs), and hematopoietic stem cells (HSCs) represent the most investigated types of stem cells for the treatment of SCI in preclinical and clinical studies. The microenvironment of SCI has a significant impact on the survival, proliferation, and differentiation of transplanted stem cells. Therefore, a deep understanding of the pathophysiology of SCI and molecular mechanisms through which stem cells act may help improve the treatment efficacy of SCT and find new therapeutic approaches such as stem-cell-derived exosomes, gene-modified stem cells, scaffolds, and nanomaterials. In this literature review, the pathogenesis of SCI and molecular mechanisms of action of multipotent stem cells including MSCs, NSCs, and HSCs are comprehensively described. Moreover, the clinical efficacy of multipotent stem cells in SCI treatment, an optimal protocol of stem cell administration, and recent therapeutic approaches based on or combined with SCT are also discussed.

Intrathecal Cell Therapy with Autologous Bone Marrow Stromal Cells as a New Tool for Neurologic Sequels after Spinal Cord Surgery: A Report of Two Cases

Background aims: The possibility of permanent neurological sequels after surgery of benign lesions affecting the spinal cord is well known. Frequently, they are irreversible, with no effective treatment other than rehabilitation. However, in recent years, intrathecal cell therapy with autologous bone marrow stromal cells (MSCs) in patients with incomplete paraplegia has shown benefits for diverse sequels of spinal cord injury (SCI). Methods: We present two patients with chronic spinal cord sequels after a surgery, who underwent cell therapy treatment with NC1 medicament (repeated intrathecal administrations of MSCs). Results: In both cases, cell therapy achieved a clear improvement in neurological sequels, such as recovery of gait disturbances, bowel dysfunction, or neuropathic pain. Conclusion: Intrathecal cell therapy with autologous MSCs offers a new approach for neurological sequels after spinal cord surgery.