Stem cells translational medicine
Công bố khoa học tiêu biểu
* Dữ liệu chỉ mang tính chất tham khảo
Mặc dù các khái niệm ban đầu về liệu pháp tế bào gốc nhằm thay thế mô bị mất, nhưng bằng chứng gần đây đã gợi ý rằng cả tế bào gốc và tiền thân đều thúc đẩy phục hồi thần kinh sau thiếu máu cục bộ thông qua các yếu tố tiết ra giúp phục hồi khả năng tái cấu trúc của não bị tổn thương. Cụ thể, các túi ngoại tiết (EVs) từ các tế bào gốc như exosomes đã được đề xuất gần đây có vai trò trung gian cho các tác dụng phục hồi của tế bào gốc. Để xác định liệu EVs có thực sự cải thiện suy giảm thần kinh sau thiếu máu cục bộ và tái cấu trúc não hay không, chúng tôi đã so sánh có hệ thống các tác động của các túi ngoại tiết (MSC-EVs) từ tế bào gốc trung mô (MSCs) so với MSCs được truyền i.v. vào chuột trong các ngày 1, 3 và 5 (MSC-EVs) hoặc ngày 1 (MSCs) sau khi xảy ra thiếu máu cục bộ não tiêu điểm ở chuột C57BL6. Trong 28 ngày sau khi đột quỵ, các điểm yếu về phối hợp vận động, tổn thương não trên mô học, phản ứng miễn dịch trong máu ngoại vi và não, cùng những thay đổi về tạo mạch và sinh trưởng tâm thần kinh đã được phân tích. Cải thiện suy giảm thần kinh và bảo vệ thần kinh dài hạn kết hợp với tăng cường tạo mạch thần kinh và thần kinh đã được ghi nhận ở các con chuột bị đột quỵ nhận EVs từ hai dòng MSC nguồn gốc tủy xương khác nhau. Việc sử dụng MSC-EV mô phỏng chính xác các phản ứng của MSCs và kéo dài suốt giai đoạn quan sát. Mặc dù sự xâm nhập của tế bào miễn dịch não không bị ảnh hưởng bởi MSC-EVs, sự suy giảm miễn dịch sau thiếu máu cục bộ (tức là B-cell, tế bào giết tự nhiên và lymphopenia tế bào T) đã giảm bớt trong máu ngoại vi ở 6 ngày sau thiếu máu cục bộ, cung cấp môi trường ngoại vi thích hợp cho tái cấu trúc não thành công. Vì các nghiên cứu gần đây cho thấy MSC-EVs an toàn với con người, nghiên cứu này cung cấp bằng chứng lâm sàng quan trọng cần thiết cho các nghiên cứu chứng minh nhanh chóng trong bệnh nhân đột quỵ.
Cấy ghép các tế bào gốc trung mô (MSCs) cung cấp một phương pháp tiếp cận hỗ trợ quan trọng bên cạnh việc làm tan cục máu đông để điều trị đột quỵ thiếu máu cục bộ. Tuy nhiên, MSCs không tích hợp vào các mạng lưới thần kinh cư trú mà hoạt động gián tiếp, gây bảo vệ thần kinh và thúc đẩy tái sinh thần kinh. Mặc dù cơ chế MSCs hoạt động còn chưa rõ ràng, bằng chứng gần đây đã gợi ý rằng các túi ngoại tiết (EVs) có thể chịu trách nhiệm cho các tác dụng gây ra bởi MSCs dưới điều kiện sinh lý và bệnh lý. Nghiên cứu hiện tại đã chứng minh rằng EVs không thua kém MSCs trong mô hình đột quỵ động vật gặm nhấm. EVs gây bảo vệ thần kinh lâu dài, thúc đẩy tái sinh thần kinh và phục hồi chức năng thần kinh, và điều tiết các phản ứng miễn dịch sau đột quỵ ngoại biên. Ngoài ra, vì EVs dung nạp tốt ở người theo báo cáo trước đó, việc sử dụng EVs trong điều kiện lâm sàng có thể mở đường cho một định nghĩa điều trị đột quỵ mới và sáng tạo mà không có các tác dụng phụ dự kiến liên quan đến cấy ghép tế bào gốc.
We aimed to evaluate efficiency and safety of transplantation of limbal stem cells (LSC) cultured on human amniotic membrane with no feeders and to compare cultured LSC with limbal tissue transplantation. Thirty eyes with stage III LSC deficiency were treated with autologous (autoLSC) or allogeneic (alloLSC) cultured LSC transplantation (prospective phase II clinical trial; average follow-up time, 72 months) or autologous (autoLT) or allogeneic (alloLT) limbal tissue transplantation (retrospective control group; average follow-up time, 132 months) between 1993 and 2014. The 5-year graft survival defined by absence of recurrence of the clinical signs of limbal deficiency was 71% for autoLSC, 0% for alloLSC, 75% for autoLT, and 33% for alloLT. Visual acuity improved by 9.2 lines for autoLSC and 3.3 lines for autoLT. It decreased by 0.7 lines for alloLSC and 1.9 lines for alloLT. Adverse events were recorded in 1/7 autoLSC, 7/7 alloLSC, 6/8 autoLT, and 8/8 alloLT patients. Corneal epithelial defect was the only adverse event recorded after autoLSC, whereas severe sight-threatening adverse events were recorded in the remaining three groups. Compared with failed grafts, successful grafts featured greater decrease in fluorescein staining, greater superficial vascularization-free corneal area, lower variability of the corneal epithelial thickness, and higher corneal epithelial basal cell density. Autologous cultured LSC transplantation was associated with high long-term survival and dramatic improvement in vision and was very safe. Autologous limbal tissue transplantation resulted in similar efficiency but was less safe. Cadaver allogeneic grafts resulted in low long-term success rate and high prevalence of serious adverse events. Stem Cells Translational Medicine 2019;8:1230&1241
Limbal stem cell deficiency (LSCD) is an eye disorder in which the stem cells responsible for forming the surface skin of the cornea are destroyed by disease. This results in pain, loss of vision, and a cosmetically unpleasant appearance. Many new treatments, including stem cell therapies, are emerging for the treatment of this condition, but assessment of these new technologies is severely hampered by the lack of biomarkers for this disease or validated tools for assessing its severity. The aims of this study were to design and test the reliability of a tool for grading LSCD, to define a set of core outcome measures for use in evaluating treatments for this condition, and to demonstrate their utility. This was achieved by using our defined outcome set (which included the Clinical Outcome Assessment in Surgical Trials of Limbal stem cell deficiency [COASTL] tool) to evaluate the 3-year outcomes for allogeneic ex vivo cultivated limbal epithelial transplantation (allo-CLET) in patients who had bilateral total LSCD secondary to aniridia or Stevens-Johnson syndrome. The results demonstrate that our new grading tool for LSCD, the COASTL tool, is reliable and repeatable, and that improvements in the biomarkers used in this tool correlate positively with improvements in visual acuity. The COASTL tool showed that following allo-CLET there was a decrease in LSCD severity and an increase in visual acuity up to 12 months post-treatment, but thereafter LSCD severity and visual acuity progressively deteriorated.
Stem cells from human corneal stroma (CSSC) suppress corneal stromal scarring in a mouse wound-healing model and promote regeneration of native transparent tissue (PMID:25504883). This study investigated efficacy of compressed collagen gel (CCG) as a vehicle to deliver CSSC for corneal therapy. CSSC isolated from limbal stroma of human donor corneas were embedded in soluble rat-tendon collagen, gelled at 37°C, and partially dehydrated to a thickness of 100 µm by passive absorption. The CCG disks were dimensionally stable, easy to handle, and could be adhered securely to de-epithelialized mouse cornea with fibrin-based adhesive. CSSC in CCG maintained >80% viability for >1 week in culture media and could be cryopreserved in 20% fetal bovine serum-10%DMSO in liquid nitrogen. CCG containing as few as 500 CSSC effectively prevented visible scarring and suppressed expression of fibrotic Col3a1 mRNA. CSSC in CCG were more effective at blocking scarring on a per-cell basis than CSSC delivered directly in a fibrin gel as previously described. Collagen-embedded cells retained the ability to suppress corneal scarring after conventional cryopreservation. This study demonstrates use of a common biomaterial that can facilitate storage and handling of stem cells in a manner that may provide off-the-shelf delivery of stem cells as a therapy for corneal scarring.
Mesenchymal stem cells (MSCs) possess great potential for use in regenerative medicine. However, their clinical application may be limited by the ability to expand their cell numbers in vitro while maintaining their differential potentials and stem cell properties. Thus the aim of this study was to test the effect of a range of medium supplements on MSC self-renewal and differentiation potential. Cells were cultured until confluent and subcultured continuously until reaching senescence. Medium supplementation with fibroblast growth factor (FGF)-2, platelet-derived growth factor (PDGF)-BB, ascorbic acid (AA), and epidermal growth factor (EGF) both increased proliferation rate and markedly increased number of cell doublings before reaching senescence, with a greater than 1,000-fold increase in total cell numbers for AA, FGF-2, and PDGF-BB compared with control cultures. Long-term culture was associated with loss of osteogenic/adipocytic differentiation potential, particularly with FGF-2 supplementation but also with AA, EGF, and PDGF-BB. In addition FGF-2 resulted in reduction in expression of CD146 and alkaline phosphatase, but this was partially reversible on removal of the supplement. Cells expressed surface markers including CD146, CD105, CD44, CD90, and CD71 by flow cytometry throughout, and expression of these putative stem cell markers persisted even after loss of differentiation potentials. Overall, medium supplementation with FGF-2, AA, EGF, and PDGF-BB greatly enhanced the total in vitro expansion capacity of MSC cultures, although differentiation potentials were lost prior to reaching senescence. Loss of differentiation potential was not reflected by changes in stem cell surface marker expression.
Myelomeningocele (MMC)—commonly known as spina bifida—is a congenital birth defect that causes lifelong paralysis, incontinence, musculoskeletal deformities, and severe cognitive disabilities. The recent landmark Management of Myelomeningocele Study (MOMS) demonstrated for the first time in humans that in utero surgical repair of the MMC defect improves lower limb motor function, suggesting a capacity for improved neurologic outcomes in this disorder. However, functional recovery was incomplete, and 58% of the treated children were unable to walk independently at 30 months of age. In the present study, we demonstrate that using early gestation human placenta-derived mesenchymal stromal cells (PMSCs) to augment in utero repair of MMC results in significant and consistent improvement in neurologic function at birth in the rigorous fetal ovine model of MMC. In vitro, human PMSCs express characteristic MSC markers and trilineage differentiation potential. Protein array assays and enzyme-linked immunosorbent assay show that PMSCs secrete a variety of immunomodulatory and angiogenic cytokines. Compared with adult bone marrow MSCs, PMSCs secrete significantly higher levels of brain-derived neurotrophic factor and hepatocyte growth factor, both of which have known neuroprotective capabilities. In vivo, functional and histopathologic analysis demonstrated that human PMSCs mediate a significant, clinically relevant improvement in motor function in MMC lambs and increase the preservation of large neurons within the spinal cord. These preclinical results in the well-established fetal ovine model of MMC provide promising early support for translating in utero stem cell therapy for MMC into clinical application for patients.
This study presents placenta-derived mesenchymal stromal cell (PMSC) treatment as a potential therapy for myelomeningocele (MMC). Application of PMSCs can augment current in utero surgical repair in the well-established and rigorously applied fetal lamb model of MMC. Treatment with human PMSCs significantly and dramatically improved neurologic function and preserved spinal cord neuron density in experimental animals. Sixty-seven percent of the PMSC-treated lambs were able to ambulate independently, with two exhibiting no motor deficits whatsoever. In contrast, none of the lambs treated with the vehicle alone were capable of ambulation. The locomotor rescue demonstrated in PMSC-treated lambs indicates great promise for future clinical trials to improve paralysis in children afflicted with MMC.
Wound healing requires a coordinated interplay among cells, growth factors, and extracellular matrix proteins. Central to this process is the endogenous mesenchymal stem cell (MSC), which coordinates the repair response by recruiting other host cells and secreting growth factors and matrix proteins. MSCs are self-renewing multipotent stem cells that can differentiate into various lineages of mesenchymal origin such as bone, cartilage, tendon, and fat. In addition to multilineage differentiation capacity, MSCs regulate immune response and inflammation and possess powerful tissue protective and reparative mechanisms, making these cells attractive for treatment of different diseases. The beneficial effect of exogenous MSCs on wound healing was observed in a variety of animal models and in reported clinical cases. Specifically, they have been successfully used to treat chronic wounds and stimulate stalled healing processes. Recent studies revealed that human placental membranes are a rich source of MSCs for tissue regeneration and repair. This review provides a concise summary of current knowledge of biological properties of MSCs and describes the use of MSCs for wound healing. In particular, the scope of this review focuses on the role MSCs have in each phase of the wound-healing process. In addition, characterization of MSCs containing skin substitutes is described, demonstrating the presence of key growth factors and cytokines uniquely suited to aid in wound repair.
Age-related (type-II) osteoporosis is a common and debilitating condition driven in part by the loss of bone marrow (BM) mesenchymal stromal cells (MSC) and their osteoblast progeny, leading to reduced bone formation. Current pharmacological regiments targeting age-related osteoporosis do not directly treat the disease by increasing bone formation, but instead use bisphosphonates to reduce bone resorption—a treatment designed for postmenopausal (type-I) osteoporosis. Recently, the bone regenerative capacity of MSCs has been found within a very rare population of skeletal stem cells (SSCs) residing within the larger heterogeneous BM-MSC pool. The osteoregenerative potential of SSCs would be an ideal candidate for cell-based therapies to treat degenerative bone diseases such as osteoporosis. However, to date, clinical and translational studies attempting to improve bone formation through cell transplantation have used the larger, nonspecific, MSC pool. In this review, we will outline the physiological basis of age-related osteoporosis, as well as discuss relevant preclinical studies that use exogenous MSC transplantation with the aim of treating osteoporosis in murine models. We will also discuss results from specific clinical trials aimed at treating other systemic bone diseases, and how the discovery of SSC could help realize the full regenerative potential of MSC therapy to increase bone formation. Finally, we will outline how ancillary clinical trials could be initiated to assess MSC/SSC-mediated bone formation gains in existing and potentially unrelated clinical trials, setting the stage for a dedicated clinical investigation to treat age-related osteoporosis.
Growth differentiation factor 15 (GDF15) is a divergent member of the transforming growth factor β family discovered in a broad range of cells, as indicated by the diversity of its nomenclature. However, the only tissue that expresses a high amount of GDF15 in the physiologic state is placenta. GDF15 is easily detected in blood, and its concentration varies with age. In fact, increased blood concentration of GDF15 is associated with numerous pathological conditions. However, the biological significance underlying these observations is far from clear. GDF15 could have a positive or negative role depending on the state of cells or their environment. Furthermore, study of its biology is hampered by lack of knowledge of its receptor and thus the signaling pathways that drive its action. GDF15 seems to be an integrative signal in pathologic conditions, giving information on severity of disease. Its effectiveness in classifying patients to modulate treatment remains to be shown. Development of therapeutic interventions with GDF15 or anti-GDF15 agents remains difficult until we uncover the mechanism that drives its activity.
Few methods are available to regenerate articular cartilage defects in patients with osteoarthritis. We aimed to assess the safety and efficacy of articular cartilage regeneration by a novel medicinal product composed of allogeneic human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs). Patients with Kellgren-Lawrence grade 3 osteoarthritis and International Cartilage Repair Society (ICRS) grade 4 cartilage defects were enrolled in this clinical trial. The stem cell-based medicinal product (a composite of culture-expanded allogeneic hUCB-MSCs and hyaluronic acid hydrogel [Cartistem]) was applied to the lesion site. Safety was assessed by the World Health Organization common toxicity criteria. The primary efficacy outcome was ICRS cartilage repair assessed by arthroscopy at 12 weeks. The secondary efficacy outcome was visual analog scale (VAS) score for pain on walking. During a 7-year extended follow-up, we evaluated safety, VAS score, International Knee Documentation Committee (IKDC) subjective score, magnetic resonance imaging (MRI) findings, and histological evaluations. Seven participants were enrolled. Maturing repair tissue was observed at the 12-week arthroscopic evaluation. The VAS and IKDC scores were improved at 24 weeks. The improved clinical outcomes were stable over 7 years of follow-up. The histological findings at 1 year showed hyaline-like cartilage. MRI at 3 years showed persistence of the regenerated cartilage. Only five mild to moderate treatment-emergent adverse events were observed. There were no cases of osteogenesis or tumorigenesis over 7 years. The application of this novel stem cell-based medicinal product appears to be safe and effective for the regeneration of durable articular cartilage in osteoarthritic knees.
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