UC blood-derived mesenchymal stromal cells: an overview

Allogeneic umbilical cord blood-derived mesenchymal stem cell implantation versus microdrilling combined with high tibial osteotomy for cartilage regeneration

This study compared cartilage regeneration outcomes in knee osteoarthritis (OA) using allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation and microdrilling with high tibial osteotomy (HTO). Fifty-four patients (60 knees) were included: 24 (27 knees) in the hUCB-MSC group and 30 (33 knees) in the microdrilling group. Both groups showed significant improvements in pain and functional scores at 6, 12, and 24 months compared to baseline. At 24 months, the hUCB-MSC group had significantly improved scores. Arthroscopic assessment at 12 months revealed better cartilage healing in the hUCB-MSC group. In subgroup analysis according to the defect site, hUCB-MSC implantation showed superior cartilage healing for anterior lesions. In conclusion, both treatments demonstrated effectiveness for medial OA. However, hUCB-MSC implantation had better patient-reported outcomes and cartilage regeneration than microdrilling. The study suggests promising approaches for cartilage restoration in large knee defects due to OA.

Adipose-Derived Stromal Vascular Fractions Are Comparable With Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells as a Supplementary Strategy of High Tibial Osteotomy for Varus Knee Osteoarthritis

Purpose

To compare the clinical, radiologic, and second-look arthroscopic outcomes of high tibial osteotomy (HTO) with stromal vascular fraction (SVF) implantation versus human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) transplantation and identify the association between cartilage regeneration and HTO outcomes.

Methods

Patients treated with HTO for varus knee osteoarthritis between March 2018 and September 2020 were retrospectively identified. In this retrospective study, among 183 patients treated with HTO for varus knee osteoarthritis between March 2018 and September 2020, patients treated with HTO with SVF implantation (SVF group; n = 25) were pair-matched based on sex, age, and lesion size with those who underwent HTO with hUCB-MSC transplantation (hUCB-MSC group; n = 25). Clinical outcomes were evaluated using the International Knee Documentation Committee score and Knee Injury and Osteoarthritis Outcome Score. Radiological outcomes evaluated were the femorotibial angle and posterior tibial slope. All patients were evaluated clinically and radiologically before surgery and during follow-up. The mean final follow-up periods were 27.8 ± 3.6 (range 24-36) in the SVF group and 28.2 ± 4.1 (range, 24-36) in the hUCB-MSC group (P = 0.690). At second-look arthroscopic surgery, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade.

Results

A total of 17 male and 33 female patients with a mean age of 56.2 years (range, 49-67 years) were included. At the time of second-look arthroscopic surgery (mean, 12.6 months; range, 11-15 months in the SVF group and 12.7 months; range, 11-14 months in the hUCB-MSC group, P = .625), the mean International Knee Documentation Committee score and Knee Injury and Osteoarthritis Outcome Score in each group significantly improved (P < .001 for all), and clinical outcomes at final follow-up further improved in both groups when compared with the values at second-look arthroscopic surgery (P < .05 for all). Overall ICRS grades, which significantly correlated with clinical outcomes, were similar between groups with no significant differences (P = .170 for femoral condyle and P = .442 for tibial plateau). Radiologic outcomes at final follow-up showed improved knee joint alignment relative to preoperative conditions but showed no significant correlation with clinical outcomes or ICRS grade in either group (P > .05 for all).

Conclusions

Improved clinical and radiological outcomes and favorable cartilage regeneration were seen after surgery for varus Knee OA in both SVF and hUCB-MSC groups.

Level of Evidence

Level III, retrospective comparative study.

Bone Marrow Aspirate Concentrate versus Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells for Combined Cartilage Regeneration Procedure in Patients Undergoing High Tibial Osteotomy: A Systematic Review and Meta-Analysis

Background and objectives: Cartilage regeneration using mesenchymal stem cells (MSCs) has been attempted to improve articular cartilage regeneration in varus knee osteoarthritis (OA) patients undergoing high tibial osteotomy (HTO). Bone marrow aspirate concentrate (BMAC) and human umbilical cord blood-derived MSCs (hUCB-MSCs) have been reported to be effective. However, whether BMAC is superior to hUCB-MSCs remains unclear. This systematic review and meta-analysis aimed to determine the clinical efficacy of cartilage repair procedures with BMAC or hUCB-MSCs in patients undergoing HTO. Materials and Methods: A systematic search was conducted using three global databases, PubMed, EMBASE, and the Cochrane Library, for studies in which the clinical outcomes after BMAC or hUCB-MSCs were used in patients undergoing HTO for varus knee OA. Data extraction, quality control, and meta-analysis were performed. To compare the clinical efficacy of BMAC and hUCB-MSCs, reported clinical outcome assessments and second-look arthroscopic findings were analyzed using standardized mean differences (SMDs) with 95% confidence intervals (CIs). Results: The present review included seven studies of 499 patients who received either BMAC (BMAC group, n = 169) or hUCB-MSCs (hUCB-MSC group, n = 330). Improved clinical outcomes were found in both BMAC and hUCB-MSC groups; however, a significant difference was not observed between procedures (International Knee Documentation Committee score; p = 0.91, Western Ontario and McMaster Universities OA Index; p = 0.05, Knee Society Score (KSS) Pain; p = 0.85, KSS Function; p = 0.37). On second-look arthroscopy, the hUCB-MSC group showed better International Cartilage Repair Society Cartilage Repair Assessment grade compared with the BMAC group (p < 0.001). Conclusions: Both BMAC and hUCB-MSCs with HTO improved clinical outcomes in varus knee OA patients, and there was no difference in clinical outcomes between them. However, hUCB-MSCs were more effective in articular cartilage regeneration than BMAC augmentation.

Allogeneic Umbilical Cord-Blood-Derived Mesenchymal Stem Cells and Hyaluronate Composite Combined with High Tibial Osteotomy for Medial Knee Osteoarthritis with Full-Thickness Cartilage Defects

Background and Objectives: Although the effects of cartilage repair in patients who are undergoing high tibial osteotomy (HTO) remains controversial, cartilage repair may be required for the full-thickness cartilage defect because of a concern of lower clinical outcome. The purpose of this study was to investigate clinical outcome and cartilage repair following implantation of allogeneic umbilical cord-blood-derived MSCs (UCB-MSCs)-hyaluronate composite in patients who received HTO for medial knee osteoarthritis (OA) with full-thickness cartilage defect. Materials and Methods: Inclusion criteria were patients with a medial knee OA, a full-thickness cartilage defect (International Cartilage Repair Society (ICRS) grade IV) ≥  3 cm² of the medial femoral condyle, and a varus deformity  ≥  5°. The full-thickness cartilage defect was treated with implantation of an allogeneic UCB-MSCs-hyaluronate composite following medial open-wedge HTO. Visual analogue scale for pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were assessed at each follow-up. Cartilage repair was assessed by the ICRS cartilage repair assessment system at second-look arthroscopy when the plate was removed. Results: Twelve patients (mean age 56.1 years; mean defect size: 4.5 cm²) were included, and 10 patients underwent second-look arthroscopy during plate removal after a minimum of 1 year after the HTO. At the final follow-up of mean 2.9 years (range; 1-6 years), all clinical outcomes had improved. At second-look arthroscopy, repaired tissue was observed in all cases. One case (10%) showed grade I, seven (70%) cases showed grade II, and two (20%) cases showed grade III according to ICRS cartilage repair assessment system, which meant that 80% showed an overall repair assessment of "normal" or "nearly normal". Conclusion: Allogeneic UCB-MSCs-HA composite implantation combined with HTO resulted in favorable clinical outcome and cartilage repair in all cases. These findings suggest that UCB-MSCs-HA composite implantation combined with HTO would be a good therapeutic option for patients with knee OA and full-thickness cartilage defects.

Silencing SIRT5 induces the senescence of UCB-MSCs exposed to TNF-α by reduction of fatty acid β-oxidation and anti-oxidation

Tumor necrosis factor-α (TNF-α) is an inflammatory cytokine involved in cell survival, apoptosis, and homeostasis. However, the regulatory effect of TNF-α on mesenchymal stem cell (MSC) redox regulation remains unknown. The process of delaying the senescence of MSCs and maintaining antioxidation mechanism is important in transplantation therapy to treat inflammatory diseases that result from restricted immunomodulatory effects of senescent MSCs. Thus, we examined the role of TNF-α-mediated signaling and its regulatory mechanisms on the senescence of umbilical cord blood-derived MSCs (UCB-MSCs) and identified its therapeutic efficacy in a collagen-induced arthritis (CIA) mouse model. We found that TNF-α increased fatty acid synthesis and lipid droplet (LD) formation through NF-κB/SREBP1-mediated FASN, SCD1, and DGAT2 expression, which protects UCB-MSCs from oxidative stress against accumulated toxic lipids. Additionally, DGAT2-mediated LD formation was regulated by TNF-α-activated TNF receptor (TNFR)1 signaling. We also found that storage of unsaturated FAs in LDs is regulated by SIRT5-dependent β-oxidation of FAs, which reduces mitochondrial ROS (mtROS) accumulation. Particularly, mtROS homeostasis was maintained by superoxide dismutase 2 (SOD2) upregulation through TNFR2-mediated SIRT5/Nrf2 signaling. In a CIA mouse model, UCB-MSCs transfected with SIRT5 siRNA exhibited reduced therapeutic effects compared with UCB-MSCs transfected with NT siRNA. Overall, the results indicated that SIRT5 plays a central role in protecting TNF-α-induced UCB-MSC senescence through FA β-oxidation and SOD2-mediated antioxidation.

Implication of Mesenchymal Stem Cells and Their Derivates for Osteochondral Regeneration

Healing of articular cartilage defects presents a challenging issue, due to its regenerative shortcomings. Lacking vascularity and innervation of cartilage and low proliferative potential of chondrocytes are the main reasons for the limited healing potential of articular cartilage. Traditional reparative approaches are limited in their efficiency, hence there is a demand for novel reparative treatments. Mesenchymal stromal cells, preferred for clinical uses, can be readily derived from various sources and have been proven to have a therapeutic effect on cartilage and subchondral bone. Therefore, mesenchymal stromal cells, their derivates, and scaffolds have been utilized in research targeting osteochondral regeneration. The present review aims to comprehensively outline and discuss literature considering this topic published within last 5 years.

Optimization of human umbilical cord blood-derived mesenchymal stem cell isolation and culture methods in serum- and xeno-free conditions

BACKGROUND

Although umbilical cord blood (UCB) is identified as a source of mesenchymal stem cells (MSCs) with various advantages, the success in cell isolation is volatile. Therefore, it is necessary to optimize methods of cord blood-derived MSC (UCB-MSC) isolation and culture. In this study, we evaluated the efficiency of UCB-MSC isolation and expansion using different commercially available serum- and xeno-free media and investigated the capacity of autologous serum and plasma as a supplement to support cell proliferation. Additionally, we defined the presence of multilineage-differentiating stress-enduring (Muse) cells in the UCB-MSC population. Functions of UCB-MSC in in vitro angiogenesis processes and anti-cancer were also verified.

METHODS

Mononuclear cells were isolated using density gradient separation and cultured in four commercial media kits, as well as four surface coating solutions. UCB-MSCs were characterized and tested on tube formation assay, and co-cultured with SK-MEL cells in a transwell system.

RESULTS

The results showed that only StemMACS™ MSC Expansion Media is more appropriate to isolate and culture UCB-MSCs. The cells exhibited a high cell proliferation rate, CFU forming capability, MSC surface marker expression, trilineage differentiate potential, and chromosome stability. In addition, the culture conditions with autologous serum coating and autologous plasma supplement enhanced cell growth and colony forming. This cell population contained Muse cells at rate of 0.3%. Moreover, UCB-MSCs could induce the tube formation of human umbilical vein endothelial cells and inhibit more than 50% of SK-MEL cell growth.

CONCLUSIONS

UCB-MSCs could be high-yield isolated and expanded under serum- and xeno-free conditions by using the StemMACS™ MSC Expansion Media kit. Autologous serum coating and plasma supplement enhanced cell proliferation. These UCB-MSCs had effected the tube formation process and an anti-cancer impact.

Allogenic umbilical cord blood-derived mesenchymal stromal cell implantation was superior to bone marrow aspirate concentrate augmentation for cartilage regeneration despite similar clinical outcomes

PURPOSE

The aim of this study was to compare clinical and second-look arthroscopic outcomes between bone marrow aspirate concentrate (BMAC) augmentation and human umbilical cord blood-derived mesenchymal stromal cell (hUCB-MSC) implantation in high tibial osteotomy (HTO) for medial compartmental knee osteoarthritis and identify the relationship between articular cartilage regeneration and HTO outcomes.

METHODS

A total of 176 patients who underwent HTO combined with a BMAC or hUCB-MSC procedure for medial compartment osteoarthritis (Kellgren-Lawrence grade 3) between June 2014 and September 2018 with a minimum follow-up of 2 years were reviewed. After HTO, multiple holes were drilled at cartilage defect sites of the medial femoral condyle (MFC), and then prepared BMAC or hUCB-MSCs in combination with scaffolds were implanted in the MFC lesions. After propensity score matching based on sex, age, body mass index, and lesion size, 55 patients in each of the BMAC and hUCB-MSC groups were successfully matched. Second-look arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system and Koshino staging system. Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), Short-Form 36 (SF-36), and Tegner activity scores.

RESULTS

At a mean follow-up of 33 months, clinical outcomes including IKDC, KOOS, SF-36, and Tegner activity scores were significantly improved in both groups (p < 0.001); however, there were no differences between the two groups. Second-look arthroscopy showed better healing of regenerated cartilage in the hUCB-MSC group (Grade I [4 cases, 9.1%]; Grade II [30 cases, 68.2%]; Grade III [11 cases, 22.7%]) than in the BMAC group (Grade I [1 case, 2.7%]; Grade II [20 cases, 54.1%]; Grade III [11 cases, 29.7%]; Grade IV [5 cases, 13.5%]) according to the ICRS CRA grading system (p = 0.040). There was no significant intergroup difference in terms of defect coverage based on the Koshino staging system (p = 0.057). Moreover, ICRS CRA grades at second-look arthroscopy were significantly correlated with clinical outcomes (r = - 0.337; p = 0.002).

CONCLUSION

There were no significant differences in the clinical outcomes between the two groups. Both treatments provided similar, reliable outcomes in terms of pain relief, functional scores, and quality of life at a mean follow-up of 33 months. However, hUCB-MSC implantation was more effective than BMAC augmentation for articular cartilage regeneration.

Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Are More Effective Than Bone Marrow Aspiration Concentrate for Cartilage Regeneration After High Tibial Osteotomy in Medial Unicompartmental Osteoarthritis of Knee

PURPOSE

The purpose of this study was to compare the outcome of cartilage regeneration between bone marrow aspirate concentrate (BMAC) augmentation and allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSCs) transplantation in high tibial osteotomy (HTO) with microfracture (MFX) for medial unicompartmental osteoarthritis (OA) of the knee in the young and active patient.

METHODS

Between January 2015 and December 2019, the patients who underwent HTO and arthroscopy with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA with kissing lesion, which was shown full-thickness cartilage defect (≥ International Cartilage Repair Society [ICRS] grade 3B) in medial femoral cartilage and medial tibial cartilage, were include in this study. Retrospectively we compared clinical outcomes, including Hospital for Special Surgery score, Knee Society Score (KSS) pain and function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between BMAC and hUCB-MSCs group at minimum of 1-year follow-up. Also, second-look arthroscopy was performed simultaneously with removal of the plate after complete bone union. Cartilage regeneration was graded by the ICRS grading system at second-look arthroscopy. Radiological measurement including hip-knee-ankle (HKA) angle, posterior tibial slope angle, and correction angle were assessed.

RESULTS

Of 150 cases that underwent HTO with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA, 123 cases underwent plate removal and second-look arthroscopy after a minimum of 1 year after the HTO surgery. Seventy-four cases were kissing lesion in medial femoral cartilage and medial tibial cartilage during initial HTO surgery. Finally, the BMAC group composed of 42 cases and hUCB-MSCs group composed of 32 cases were retrospectively identified in patients who had kissing lesions and second-look arthroscopies with a minimum of 1 year of follow-up. At the final follow-up of mean 18.7 months (standard deviation = 4.6 months), clinical outcomes in both groups had improved. However, there were no significant differences between the IKDC, WOMAC, or KSS pain and function scores in the 2 groups (P > .05). At second-look arthroscopy, the ICRS grade was significantly better in the hUCB-MSC group than in the BMAC group in both medial femoral and medial tibial cartilage (P = .001 for both). The average ICRS grade of the BMAC group improved from 3.9 before surgery to 2.8 after surgery. The average ICRS grade of the hUBC-MSC group improved from 3.9 before surgery to 2.0 after surgery. Radiological findings comparing postoperative HKA angle, posterior tibial slope angle, and correction angle showed no significant differences between the groups (P > .05). Therefore it was found that the postoperative correction amount did not affect the postoperative cartilage regeneration results.

CONCLUSIONS

We found that the hUCB-MSC procedure was more effective than the BMAC procedure for cartilage regeneration in medial unicompartmental knee OA even though the clinical outcomes improved regardless of which treatment was administered.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Allogeneic Umbilical Cord Blood-Derived Mesenchymal Stem Cell Implantation Versus Microfracture for Large, Full-Thickness Cartilage Defects in Older Patients: A Multicenter Randomized Clinical Trial and Extended 5-Year Clinical Follow-up

Background:

There is currently no optimal method for cartilage restoration in large, full-thickness cartilage defects in older patients.

Purpose:

To determine whether implantation of a composite of allogeneic umbilical cord blood–derived mesenchymal stem cells and 4% hyaluronate (UCB-MSC-HA) will result in reliable cartilage restoration in patients with large, full-thickness cartilage defects and whether any clinical improvements can be maintained up to 5 years postoperatively.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A randomized controlled phase 3 clinical trial was conducted for 48 weeks, and the participants then underwent extended 5-year observational follow-up. Enrolled were patients with large, full-thickness cartilage defects (International Cartilage Repair Society [ICRS] grade 4) in a single compartment of the knee joint, as confirmed by arthroscopy. The defect was treated either with UCB-MSC-HA implantation through mini-arthrotomy or with microfracture. The primary outcome was proportion of participants who improved by ≥1 grade on the ICRS Macroscopic Cartilage Repair Assessment (blinded evaluation) at 48-week arthroscopy. Secondary outcomes included histologic assessment; changes in pain visual analog scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and International Knee Documentation Committee (IKDC) score from baseline; and adverse events.

Results:

Among 114 randomized participants (mean age, 55.9 years; 67% female; body mass index, 26.2 kg/m²), 89 completed the phase 3 clinical trial and 73 were enrolled in the 5-year follow-up study. The mean defect size was 4.9 cm² in the UCB-MSC-HA group and 4.0 cm² in the microfracture group (P = .051). At 48 weeks, improvement by ≥1 ICRS grade was seen in 97.7% of the UCB-MSC-HA group versus 71.7% of the microfracture group (P = .001); the overall histologic assessment score was also superior in the UCB-MSC-HA group (P = .036). Improvement in VAS pain, WOMAC, and IKDC scores were not significantly different between the groups at 48 weeks, however the clinical results were significantly better in the UCB-MSC-HA group at 3- to 5-year follow-up (P < .05). There were no differences between the groups in adverse events.

Conclusion:

In older patients with symptomatic, large, full-thickness cartilage defects with or without osteoarthritis, UCB-MSC-HA implantation resulted in improved cartilage grade at second-look arthroscopy and provided more improvement in pain and function up to 5 years compared with microfracture.

Registration:

NCT01041001, NCT01626677 (ClinicalTrials.gov identifier).

Characterization of traumatized muscle-derived multipotent progenitor cells from low-energy trauma

Background

Multipotent progenitor cells have been harvested from different human tissues, including the bone marrow, adipose tissue, and umbilical cord blood. Previously, we identified a population of mesenchymal progenitor cells (MPCs) isolated from the traumatized muscle of patients undergoing reconstructive surgery following a war-related blast injury. These cells demonstrated the ability to differentiate into multiple mesenchymal lineages. While distal radius fractures from a civilian setting have a much lower injury mechanism (low-energy trauma), we hypothesized that debrided traumatized muscle near the fracture site would contain multipotent progenitor cells with the ability to differentiate and regenerate the injured tissue.

Methods

The traumatized muscle was debrided from the pronator quadratus in patients undergoing open reduction and internal fixation for a distal radius fracture at the Walter Reed National Military Medical Center. Using a previously described protocol for the isolation of MPCs from war-related extremity injuries, cells were harvested from the low-energy traumatized muscle samples and expanded in culture. Isolated cells were characterized by flow cytometry and q-RT-PCRs and induced to adipogenic, osteogenic, and chondrogenic differentiation. Downstream analyses consisted of lineage-specific staining and q-RT-PCR.

Results

Cells isolated from low-energy traumatized muscle samples were CD73+, CD90+, and CD105+ that are the characteristic of adult human mesenchymal stem cells. These cells expressed high levels of the stem cell markers OCT4 and NANOG 1-day after isolation, which was dramatically reduced over-time in monolayer culture. Following induction, lineage-specific markers were demonstrated by each specific staining and confirmed by gene expression analysis, demonstrating the ability of these cells to differentiate into adipogenic, osteogenic, and chondrogenic lineages.

Conclusions

Adult multipotent progenitor cells are an essential component for the success of regenerative medicine efforts. While MPCs have been isolated and characterized from severely traumatized muscle from high-energy injuries, here, we report that cells with similar characteristics and multipotential capacity have been isolated from the tissue that was exposed to low-energy, community trauma.

Daphne mucronata enhances cell proliferation and protects human adipose stem cells against monosodium iodoacetate induced oxidative stress in vitro

Mesenchymal stem cells (MSCs) are being used to treat many diseases as they exhibit great regenerative potential. However, MSC's transplantation sometimes does not yield the maximum regenerative outcome as they are unable to survive in inflammatory conditions. Several approaches including preconditioning are used to improve the survival rate of mesenchymal stem cells. One such recently reported approach is preconditioning MSCs with plant extracts. The present study was designed to evaluate the effect of Daphne mucronata extract on stressed human adipose-derived mesenchymal stem cells (hADMSCs). Isolated hADMSCs were preconditioned with different concentrations of Daphne muconata extract and the protective, proliferative, antioxidant and anti-inflammatory effect was assessed through various assays and expression analysis of inflammatory markers regulated through NF-κB pathway. Results suggest that preconditioning hADMSCs with Daphne mucronata increased the cell viability, proliferative and protective potential of hADMSCs with a concomitant reduction in LDH, ROS and elevation in SOD activity. Moreover, both the ELISA and gene expression analysis demonstrated down regulations of inflammatory markers (IL1-β, TNF-α, p65, p50, MMP13) in Daphne mucronata preconditioned hADMSCs as compared to stress. This is the first study to report the use of MIA induced oxidative stress against hADMSC's and effect of Daphne mucronata on stressed hADMSCs. Results of these studies provided evidence that Daphne mucronata protects the hADMSCs during stress conditions by down regulating the inflammatory markers and hence increase the viability and proliferative potential of hADMSCs that is crucial for transplantation purposes.

Immune Tolerance Induction Using Cell-Based Strategies in Liver Transplantation: Clinical Perspectives

Liver transplantation (LT) has become the best chance and a routine practice for patients with end-stage liver disease and small hepatocellular carcinoma. However, life-long immunosuppressive regimens could lead to many post-LT complications, including cancer recurrence, infections, dysmetabolic syndrome, and renal injury. Impeccable management of immunosuppressive regimens is indispensable to ensure the best long-term prognosis for LT recipients. This is challenging for these patients, who probably have a post-LT graft survival of more than 10 or even 20 years. Approximately 20% of patients after LT could develop spontaneous operational tolerance. They could maintain normal graft function and histology without any immunosuppressive regimens. Operational tolerance after transplantation has been an attractive and ultimate goal in transplant immunology. The liver, as an immunoregulatory organ, generates an immune hyporesponsive microenvironment under physiological conditions. In this regard, LT recipients may be ideal candidates for studies focusing on operative tolerance. Cell-based strategies are one of the most promising methods for immune tolerance induction, including chimerism induced by hematopoietic stem cells and adoptive transfer of regulatory T cells, regulatory dendritic cells, regulatory macrophages, regulatory B cells, and mesenchymal stromal cells. The safety and the efficacy of many cell products have been evaluated by prospective clinical trials. In this review, we will summarize the latest perspectives on the clinical application of cell-based strategies in LT and will address a number of concerns and future directions regarding these cell products.

Metabolomic Analysis Reveals That the Mechanism of Astaxanthin Improves the Osteogenic Differentiation Potential in Bone Marrow Mesenchymal Stem Cells

At present, little research has been done on the metabolic phenotype of the differentiation of mesenchymal stem cells (MSCs) into osteoblasts. In this study, the effect of astaxanthin on improving osteogenic differentiation potential of mesenchymal stem cells was studied by metabolomics. Results showed that L-methionine, L-tyrosine, and 2-hydroxycinnamic acid were upregulated in MSCs treated with astaxanthin, while L-lysine, L-pipecolic acid, L-histidine, L-arginine, D-fructose, and L-aspartic acid were downregulated in samples treated with astaxanthin. In addition, astaxanthin exhibited a significant dose-dependent relationship with these markers. Metabolic pathway enrichment analysis revealed that AST mainly regulated phenylalanine metabolism; phenylalanine, tyrosine, and tryptophan biosynthesis; and pantothenate and CoA biosynthesis during the process of osteogenic differentiation of MSCs. Furthermore, the staining results showed that astaxanthin could actively promote the osteogenic differentiation of mesenchymal stem cells. These findings clearly indicate that astaxanthin plays an important role in inducing osteogenic differentiation of mesenchymal stem cells. In addition, the changed metabolites can be used to monitor the differentiation process.

A Rabbit Model of Osteochondral Regeneration Using Three-Dimensional Printed Polycaprolactone-Hydroxyapatite Scaffolds Coated with Umbilical Cord Blood Mesenchymal Stem Cells and Chondrocytes

BACKGROUND This study aimed to investigate a rabbit model of osteochondral regeneration using three-dimensional (3-D) printed polycaprolactone-hydroxyapatite (PCL-HA) scaffolds coated with umbilical cord blood mesenchymal stem cells (UCB-MSCs) and chondrocytes. MATERIAL AND METHODS Nine female New Zealand white rabbits were included in the study. The 3-D PCL-HA scaffolds were prepared using fused deposition modeling 3-D printing technology. Seeding cells were prepared by co-culture of rabbit UCB-MSCs and chondrocytes with a ratio of 3: 1. A total of 4×10⁶ cells were seeded on 3-D PCL-HA scaffolds and implanted into rabbits with femoral trochlear defects. After 8 weeks of in vivo implantation, 12 specimens were sampled and examined using histology and scanning electron microscopy (SEM). The International Cartilage Repair Society (ICRS) macroscopic scores and histological results were recorded and compared with those of the unseeded PCL-HA scaffolds. RESULTS Mean ICRS scores for the UCB-MSCs and chondrocyte-seeded PCL-HA scaffolds (group A) were significantly higher than the normal unseeded control (NC) PCL-HA scaffold group (group B) (P<0.05). Histology with safranin-O and fast-green staining showed that the UCB chondrocyte-seeded PCL-HA scaffolds significantly promoted bone and cartilage regeneration. CONCLUSIONS In a rabbit model of osteochondral regeneration using 3-D printed PCL-HA scaffolds, the UCB chondrocyte-seeded PCL-HA scaffold promoted articular cartilage repair when compared with the control or non-seeded PCL-HA scaffolds.

O-cyclic phytosphingosine-1-phosphate stimulates HIF1α-dependent glycolytic reprogramming to enhance the therapeutic potential of mesenchymal stem cells

O-cyclic phytosphingosine-1-phosphate (cP1P) is a novel chemically synthesized sphingosine metabolite derived from phytosphingosine-1-phosphate. Although structurally similar to sphingosine-1-phosphate (S1P), its biological properties in stem cells remain to be reported. We investigated the effect of cP1P on the therapeutic potential of mesenchymal stem cells (MSCs) and their regulatory mechanism. We found that, under hypoxia, cP1P suppressed MSC mitochondrial dysfunction and apoptosis. Metabolic data revealed that cP1P stimulated glycolysis via the upregulation of glycolysis-related genes. cP1P-induced hypoxia-inducible factor 1 alpha (HIF1α) plays a key role for MSC glycolytic reprogramming and transplantation efficacy. The intracellular calcium-dependent PKCα/mammalian target of the rapamycin (mTOR) signaling pathway triggered by cP1P regulated HIF1α translation via S6K1, which is critical for HIF1 activation. Furthermore, the cP1P-activated mTOR pathway induced bicaudal D homolog 1 expression, leading to HIF1α nuclear translocation. In conclusion, cP1P enhances the therapeutic potential of MSC through mTOR-dependent HIF1α translation and nuclear translocation.

Mesenchymal stromal cells in kidney transplantation

PURPOSE OF REVIEW

Mesenchymal stromal cells (MSC) have emerged as one of the most promising candidates for immunomodulatory cell therapy in kidney transplantation. Here we describe novel insights into the MSC mechanism of action and provide an overview of initial safety and feasibility studies with MSC in kidney transplantation.

RECENT FINDINGS

Clinical studies of MSC-based cell therapy in kidney transplant recipients demonstrated the safety and feasibility of cell therapy and provide the first encouraging evidence of the efficacy of MSC in enabling the minimization of immunosuppressive drugs. In our initial experience with MSC-based therapy in kidney transplant recipients we carried out extensive clinical and immunological monitoring of MSC-treated patients and found possible biomarkers of MSC immunomodulation in some of them. Based on these biomarkers we identified a patient in whom complete discontinuation of immunosuppression has been achieved safely and successfully.

SUMMARY

Many issues should be addressed before MSC-based therapy becomes a standard treatment protocol for kidney transplantation. A better understanding of the MSC mechanism of action and the identification of biomarkers of response to therapy will inform the rational design of the most effective clinical protocol and the selection of patients amenable to safe immunosuppressive drug withdrawal.

Comparison of Undifferentiated Versus Chondrogenic Predifferentiated Mesenchymal Stem Cells Derived From Human Umbilical Cord Blood for Cartilage Repair in a Rat Model

BACKGROUND

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have gained much interest as a promising cell source for regenerative medicine owing to the noninvasive collection, availability, high expansion capacity, and low immunogenicity. However, few in vivo studies have reported the use of hUCB-MSCs on cartilage repair. Moreover, little study has been conducted on the effects of chondrogenic predifferentiation of hUCB-MSCs on cartilage repair.

PURPOSE

To compare the effectiveness of transplanting undifferentiated versus chondrogenic predifferentiated mesenchymal stem cells (MSCs) for treating osteochondral defects.

STUDY DESIGN

Controlled laboratory study.

METHODS

Critical-sized osteochondral defects were created in the trochlear grooves of rat femurs. In 20 rats, a composite of chondrogenic predifferentiated hUCB-MSCs (chondro-MSCs) and 4% hyaluronic acid (HA) hydrogel was transplanted into defects in the right knees, whereas undifferentiated hUCB-MSCs (undiff-MSCs) and 4% HA hydrogel were transplanted into the left knees. In the control groups, 4% HA hydrogel without MSCs was transplanted into defects in the right knees, and the defects in the left knees were left untreated in 20 rats. The cartilage repair was evaluated at 8 and 16 weeks after surgery.

RESULTS

Transplanting undiff-MSCs resulted in overall superior cartilage repair as compared with chondro-MSCs, HA alone, or no treatment. The articular surfaces of the defect sites in the undiff-MSC group were relatively smoother than those of the other treatments. The undiff-MSC group showed cellular morphology and arrangement similar to surrounding normal articular cartilage tissue at 16 weeks, both of which were also better than those of the other groups. In addition, the undiff-MSC group showed coloration similar to surrounding normal articular cartilage tissue at 16 weeks in safranin O and type II collagen immunohistochemical staining. The histological scores also revealed that cartilage repair with undiff-MSCs was better than that with chondro-MSCs, HA alone, or no treatment ( P < .05 in all).

CONCLUSION

This study demonstrated that treatment with undiff-MSCs resulted in more favorable cartilage repair than that with chondro-MSCs in a rat model. These findings indicate that chondrogenic predifferentiation of MSCs before transplantation does not enhance cartilage repair.

CLINICAL RELEVANCE

The results of this study support the use of undifferentiated MSCs, rather than chondrogenic predifferentiated MSCs, as a stem cell therapy strategy for cartilage repair.

Bone Tissue Engineering Using Human Cells: A Comprehensive Review on Recent Trends, Current Prospects, and Recommendations

The use of proper cells for bone tissue engineering remains a major challenge worldwide. Cells play a pivotal role in the repair and regeneration of the bone tissue in vitro and in vivo. Currently, a large number of differentiated (somatic) and undifferentiated (stem) cells have been used for bone reconstruction alone or in combination with different biomaterials and constructs (e.g., scaffolds). Although the results of the cell transplantation without any supporting or adjuvant material have been very effective with regard to bone healing. Recent advances in bone scaffolding are now becoming new players affecting the osteogenic potential of cells. In the present study, we have critically reviewed all the currently used cell sources for bone reconstruction and discussed the new horizons that are opening up in the context of cell-based bone tissue engineering strategies.

Mesenchymal stem cells in preclinical cancer cytotherapy: a systematic review

Mesenchymal stem cells (MSC) comprise a heterogeneous population of rapidly proliferating cells that can be isolated from adult (e.g., bone marrow, adipose tissue) as well as fetal (e.g., umbilical cord) tissues (termed bone marrow (BM)-, adipose tissue (AT)-, and umbilical cord (UC)-MSC, respectively) and are capable of differentiation into a wide range of non-hematopoietic cell types. An additional, unique attribute of MSC is their ability to home to tumor sites and to interact with the local supportive microenvironment which rapidly conceptualized into MSC-based experimental cancer cytotherapy at the turn of the century. Towards this purpose, both naïve (unmodified) and genetically modified MSC (GM-MSC; used as delivery vehicles for the controlled expression and release of antitumorigenic molecules) have been employed using well-established in vitro and in vivo cancer models, albeit with variable success. The first approach is hampered by contradictory findings regarding the effects of naïve MSC of different origins on tumor growth and metastasis, largely attributed to inherent biological heterogeneity of MSC as well as experimental discrepancies. In the second case, although the anti-cancer effect of GM-MSC is markedly improved over that of naïve cells, it is yet apparent that some protocols are more efficient against some types of cancer than others. Regardless, in order to maximize therapeutic consistency and efficacy, a deeper understanding of the complex interaction between MSC and the tumor microenvironment is required, as well as examination of the role of key experimental parameters in shaping the final cytotherapy outcome. This systematic review represents, to the best of our knowledge, the first thorough evaluation of the impact of experimental anti-cancer therapies based on MSC of human origin (with special focus on human BM-/AT-/UC-MSC). Importantly, we dissect the commonalities and differences as well as address the shortcomings of work accumulated over the last two decades and discuss how this information can serve as a guide map for optimal experimental design implementation ultimately aiding the effective transition into clinical trials.

Mesenchymal stromal cell therapy: progress in manufacturing and assessments of potency

Mesenchymal stromal cell (MSC) therapies have been pursued for a broad spectrum of indications but mixed reports on clinical efficacy have given rise to some degree of skepticism regarding the effectiveness of this approach. However, recent reports of successful clinical outcomes and regulatory approvals for graft-versus-host disease, Crohn's disease and critical limb ischemia have prompted a shift in this perspective. With hundreds of clinical trials involving MSCs currently underway and an increasing demand for large-scale manufacturing protocols, there is a critical need to develop standards that can be applied to processing methods and to establish consensus assays for both MSC processing control and MSC product release. Reference materials and validated, uniformly applied tests for quality control of MSC products are needed. Here, we review recent developments in MSC manufacturing technologies, release testing and potency assays. We conclude that, although MSCs hold considerable promise clinically, economies of scale have yet to be achieved although numerous bioreactor technologies for scalable production of MSCs exist. Additionally, rigorous disease-specific product testing and comprehensive understanding of mechanisms of action, which are linked to relevant process and product release potency assays, will be required to ensure that these therapies continue to be successful.

Conditioned media from human umbilical cord blood-derived mesenchymal stem cells stimulate rejuvenation function in human skin

Developing treatments that inhibit skin aging is an important research project. Rejuvenation, which focuses on prevention of skin aging, is one of the major issues. Recent studies suggested that mesenchymal stem cells (MSCs) secrete many cytokines, which are important in wound healing. In this study, we investigated the effect of human umbilical cord blood-derived mesenchymal stem cells conditioned media (USC-CM) in cutaneous wound healing and collagen synthesis. We found that USC-CM has many useful growth factors associated with skin rejuvenation, such as Epithelial Growth Factor (EGF), basic Fibroblast Growth Factor (bFGF), Platelet Derived Growth Factor (PDGF), Hepatocyte Growth Factor (HGF), Collagen type 1, and especially, one of the rejuvenation factors, the growth differentiation factor-11 (GDF-11). Our in vitro results showed that USC-CM stimulate growth and extracellular matrix (ECM) production of Human Dermal Fibroblasts (HDFs) compared to those of other MSCs conditioned media (CM) from different origins. Moreover, we evaluated the roles of GDF-11. The results showed that GDF-11 accelerates growth, migration and ECM production of HDFs. Our In vivo results showed that topical treatment of USC-CM showed anti-wrinkle effect and significantly increased dermal density in women. In conclusion, USC-CM has various useful growth factors including GDF-11 that can stimulate skin rejuvenation by increasing growth and ECM production of HDFs.

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USC-CM has various growth factors associated with skin rejuvenation including GDF-11 that strongly promoted HDFs migration, collagen synthesis in vitro compared with HDF- and AD-MSC-CM.

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USC-CM increased dermal density and decreased skin wrinkle in human.

Intracellular Calcium Determines the Adipogenic Differentiation Potential of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells via the Wnt5a/β-Catenin Signaling Pathway

Mesenchymal stem cells- (MSCs-) based therapies show different degrees of efficacies for the treatment of various diseases, including lipogenesis. We evaluated the adipogenic differentiation ability of human umbilical cord blood-derived MSCs (hUCB-MSCs) from different donors and examined the contribution of the intracellular calcium (Ca²⁺) level to this diversity. hUCB-MSCs treated with Ca²⁺ or the Ca²⁺ chelator BAPTA-AM increased and decreased adipogenic differentiation, respectively. Canonical Wnt5a/β-catenin expression decreased during adipogenic differentiation of hUCB-MSCs. Treatment with Wnt5a blocked the adipogenic differentiation of hUCB-MSCs and activated the Wnt pathway, with a decrease in the adipogenesis markers PPARγ and leptin, and reduced lipid vacuole-associated Oil red O activity. In contrast, inhibition of the Wnt pathway with dickkopf-1 and β-catenin small interfering RNA transfection promoted the adipogenic potential of hUCB-MSCs. Interestingly, the Ca²⁺-based system exhibited a synergic effect on adipogenic potential through the Wnt5a/β-catenin pathway. Our data suggest that the variable adipogenic differentiation potential of hUCB-MSCs from different lots is due to variation in the intracellular Ca²⁺ level, which can be used as a marker to predict hUCB-MSCs selection for lipogenesis therapy. Overall, these results demonstrate that exogenous calcium treatment enhanced the adipogenic differentiation of hUCB-MSCs via negatively regulating the Wnt5a/β-catenin signaling pathway.

Mesenchymal stromal cells for tolerance induction in organ transplantation

The primary challenge in organ transplantation continues to be the need to suppress the host immune system long-term to ensure prolonged allograft survival. Long-term non-specific immunosuppression can, however, result in life-threatening complications. Thus, efforts have been pursued to explore novel strategies that would allow minimization of maintenance immunosuppression, eventually leading to transplant tolerance. In this scenario, bone marrow-derived mesenchymal stromal cells (MSC), given their unique immunomodulatory properties to skew the balance between regulatory and memory T cells, have emerged as potential candidates for cell-based therapy to promote immune tolerance. Here, we review our initial clinical experience with bone marrow-derived MSC in living-donor kidney transplant recipients and provide an overview of the available results of other clinical programs with MSC in kidney and liver transplantation, highlighting hurdles and success of this innovative cell-based therapy.

Mesenchymal Stem Cells in Kidney Repair

Every year 13.3 million people suffer acute kidney injury (AKI), which is associated with a high risk of death or development of long-term chronic kidney disease (CKD) in a substantial percentage of patients besides other organ dysfunctions. To date, the mortality rate per year for AKI exceeds 50 % at least in patients requiring early renal replacement therapy and is higher than the mortality for breast and prostate cancer, heart failure and diabetes combined.Until now, no effective treatments able to accelerate renal recovery and improve survival post AKI have been developed. In search of innovative and effective strategies to foster the limited regeneration capacity of the kidney, several studies have evaluated the ability of mesenchymal stem cells (MSCs) of different origin as an attractive therapeutic tool. The results obtained in several models of AKI and CKD document that MSCs have therapeutic potential in repair of renal injury, preserving renal function and structure thus prolonging animal survival through differentiation-independent pathways. In this chapter, we have summarized the mechanisms underlying the regenerative processes triggered by MSC treatment, essentially due to their paracrine activity. The capacity of MSC to migrate to the site of injury and to secrete a pool of growth factors and cytokines with anti-inflammatory, mitogenic, and immunomodulatory effects is described. New modalities of cell-to-cell communication via the release of microvesicles and exosomes by MSCs to injured renal cells will also be discussed. The translation of basic experimental data on MSC biology into effective care is still limited to preliminary phase I clinical trials and further studies are needed to definitively assess the efficacy of MSC-based therapy in humans.

Clinical Translation of Mesenchymal Stromal Cell Therapies in Nephrology

Mesenchymal stromal cells have emerged as potential candidates for cell-based therapies to modulate the immune response in organ transplantation and repair tissues after acute or chronic injury. Preclinical studies have shown convincingly in rodent models that mesenchymal stromal cells can prolong solid organ graft survival and that they can induce immune tolerance, accelerate recovery from AKI, and promote functional improvement in chronic nephropathies. Multiple complex properties of the cells, including immunomodulatory, anti-inflammatory, and proregenerative effects, seem to contribute. The promising preclinical studies have encouraged investigators to explore the safety, tolerability, and efficacy of mesenchymal stromal cell-based therapy in pilot clinical trials, including those for bone marrow and solid organ transplantation, autoimmune diseases, and tissue and organ repair. Here, we review the available data on culture-expanded mesenchymal stromal cells tested in renal transplantation, AKI, and CKD. We also briefly discuss the relevant issues that must be addressed to ensure rigorous assessment of the safety and efficacy of mesenchymal stromal cell therapies to allow the translation of this research into the practice of clinical nephrology.

Metabolomics Analysis of the Osteogenic Differentiation of Umbilical Cord Blood Mesenchymal Stem Cells Reveals Differential Sensitivity to Osteogenic Agents

Mesenchymal stem cells (MSCs) of fetal origin, such as umbilical cord blood MSCs (UCB MSCs), have emerged as a promising cell source for musculoskeletal tissue regeneration because of their higher proliferation potential, lack of donor site morbidity, and their off-the-shelf potential. MSCs differentiated toward the osteogenic lineage exhibit a specific metabolic phenotype characterized by reliance to oxidative phosphorylation for energy production and reduced glycolytic rates. Currently, limited information exists on the metabolic transitions at different stages of the osteogenic process after osteoinduction with different agents. Herein, the osteoinduction efficiency of BMP-2 and dexamethasone on UCB MSCs was assessed using gas chromatography-mass spectrometry (GC-MS) metabolomics analysis, revealing metabolic discrepancies at 7, 14, and 21 days of induction. Whereas both agents when administered individually were able to induce collagen I, osteocalcin, and osteonectin expression, BMP-2 was less effective than dexamethasone in promoting alkaline phosphatase expression. The metabolomics analysis revealed that each agent induced distinct metabolic alterations, including changes in amino acid pools, glutaminolysis, one-carbon metabolism, glycolysis, and tricarboxylic acid cycle. Importantly, we showed that in vitro-differentiated UCB MSCs acquire a metabolic physiology similar to primary osteoblasts when induced with dexamethasone but not with BMP-2, highlighting the fact that metabolomics analysis is sensitive enough to reveal potential differences in the osteogenic efficiency and can be used as a quality control assay for evaluating the osteogenic process.

Restoration of a large osteochondral defect of the knee using a composite of umbilical cord blood-derived mesenchymal stem cells and hyaluronic acid hydrogel: a case report with a 5-year follow-up

Background

The treatment of articular cartilage defects is a therapeutic challenge for orthopaedic surgeons. Furthermore, large osteochondral defects needs restoration of the underlying bone for sufficient biomechanical characteristics as well as the overlying cartilage.

Case presentation

A symptomatic large osteochondral defect in the knee joint was restored using a composite of umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) 0.5 x 10⁷/ml and 4% hyaluronic acid (HA) hydrogel. Significant improvements in pain and function of the knee joint were identified by the evaluation at 12 months after surgery. A hyaline-like cartilage completely filled the defect and was congruent with the surrounding normal cartilage as revealed by magnetic resonance imaging (MRI), a second-look arthroscopy and histological assessment. The improved clinical outcomes maintained until 5.5 years. MRI also showed the maintenance of the restored bony and cartilaginous tissues.

Conclusion

This case report suggests that the composite of allogeneic UCB-MSCs and HA hydrogel can be considered a safe and effective treatment option for large osteochondral defects of the knee.

Effect of Transplanting Various Concentrations of a Composite of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Hyaluronic Acid Hydrogel on Articular Cartilage Repair in a Rabbit Model

Background

Mesenchymal stem cells (MSCs) are known to have therapeutic potential for cartilage repair. However, the optimal concentration of MSCs for cartilage repair remains unclear. Therefore, we aimed to explore the feasibility of cartilage repair by human umbilical cord blood-derived MSCs (hUCB-MSCs) and to determine the optimal concentrations of the MSCs in a rabbit model.

Methods

Osteochondral defects were created in the trochlear groove of femur in 55 rabbits. Four experimental groups (11 rabbits/group) were treated by transplanting the composite of hUCB-MSCs and HA with various MSCs concentrations (0.1, 0.5, 1.0, and 1.5 x 10⁷ cells/ml). One control group was left untreated. At 4, 8, and 16 weeks post-transplantation, the degree of cartilage repair was evaluated grossly and histologically.

Findings

Overall, transplanting hUCB-MSCs and HA hydrogel resulted in cartilage repair tissue with better quality than the control without transplantation (P = 0.015 in 0.1, P = 0.004 in 0.5, P = 0.004 in 1.0, P = 0.132 in 1.5 x 10⁷ cells/ml). Interestingly, high cell concentration of hUCB-MSCs (1.5×10⁷ cells/ml) was inferior to low cell concentrations (0.1, 0.5, and 1.0 x 10⁷ cells/ml) in cartilage repair (P = 0.394,P = 0.041, P = 0.699, respectively). The 0.5 x 10⁷ cells/ml group showed the highest cartilage repair score at 4, 8 and 16 weeks post transplantation, and followed by 0.1x10⁷ cells/ml group or 1.0 x 10⁷ cell/ml group.

Conclusions

The results of this study suggest that transplantation of the composite of hUCB-MSCs and HA is beneficial for cartilage repair. In addition, this study shows that optimal MSC concentration needs to be determined for better cartilage repair.

Human umbilical cord blood-derived mesenchymal stem cells ameliorate psoriasis-like skin inflammation in mice

Mesenchymal stem cells (MSCs) inhibit the proliferation or activation of lymphocytes, and their inhibitory effects do not require human leukocyte antigen (HLA)-matching because MSCs express low levels of HLA molecules. Therefore, MSCs may be able to regulate immune responses. In this study, we determined whether MSCs could inhibit psoriasis-like skin inflammation in mice. After induction of psoriasis-like skin inflammation using intradermal injection of IL-23 or topical application of imiquimod with or without treatment with MSC, mouse skins were collected, and H&E staining and real-time PCR were performed. IL-23-induced skin inflammation was inhibited when MSCs were injected on day −1 and day 7. The expression of proinflammatory cytokines such as IL-6, IL-17, and TNF-α was inhibited by MSC injection, and the expression of chemokines such as CCL17, CCL20, and CCL27 was also decreased in mouse skin. We also determined whether MSCs could not only prevent but also treat psoriasis-like skin inflammation in mice. Furthermore, in vitro experiments also showed anti-inflammatory effects of MSCs. Dendritic cells which are co-cultured with MSCs suppressed CD4+ T cell activation and differentiation, which are important for the pathogenesis of psoriasis. These results suggest that MSCs could be useful for treating psoriasis.

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Mesenchymal stem cells inhibit psoriasis-like skin inflammation in mice.

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Mesenchymal stem cells modulate dendritic cell function.

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Dendritic cells that co-cultured with mesenchymal stem cells regulate CD4+ T cell differentiation.

Mesenchymal Stem Cell-Based Therapy for Kidney Disease: A Review of Clinical Evidence

Mesenchymal stem cells form a population of self-renewing, multipotent cells that can be isolated from several tissues. Multiple preclinical studies have demonstrated that the administration of exogenous MSC could prevent renal injury and could promote renal recovery through a series of complex mechanisms, in particular via immunomodulation of the immune system and release of paracrine factors and microvesicles. Due to their therapeutic potentials, MSC are being evaluated as a possible player in treatment of human kidney disease, and an increasing number of clinical trials to assess the safety, feasibility, and efficacy of MSC-based therapy in various kidney diseases have been proposed. In the present review, we will summarize the current knowledge on MSC infusion to treat acute kidney injury, chronic kidney disease, diabetic nephropathy, focal segmental glomerulosclerosis, systemic lupus erythematosus, and kidney transplantation. The data obtained from these clinical trials will provide further insight into safety, feasibility, and efficacy of MSC-based therapy in renal pathologies and allow the design of consensus protocol for clinical purpose.

Cartilage Regeneration in Osteoarthritic Patients by a Composite of Allogeneic Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Hyaluronate Hydrogel: Results from a Clinical Trial for Safety and Proof-of-Concept with 7 Years of Extended Follow-Up

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. Stem Cells Translational Medicine2017;6:613–621

Current View on Osteogenic Differentiation Potential of Mesenchymal Stromal Cells Derived from Placental Tissues

Mesenchymal stromal cells (MSC) isolated from human term placental tissues possess unique characteristics, including their peculiar immunomodulatory properties and their multilineage differentiation potential. The osteogenic differentiation capacity of placental MSC has been widely disputed, and continues to be an issue of debate. This review will briefly discuss the different MSC populations which can be obtained from different regions of human term placenta, along with their unique properties, focusing specifically on their osteogenic differentiation potential. We will present the strategies used to enhance osteogenic differentiation potential in vitro, such as through the selection of subpopulations more prone to differentiate, the modification of the components of osteo-inductive medium, and even mechanical stimulation. Accordingly, the applications of three-dimensional environments in vitro and in vivo, such as non-synthetic, polymer-based, and ceramic scaffolds, will also be discussed, along with results obtained from pre-clinical studies of placental MSC for the regeneration of bone defects and treatment of bone-related diseases.

Advancing biomaterials of human origin for tissue engineering

Biomaterials have played an increasingly prominent role in the success of biomedical devices and in the development of tissue engineering, which seeks to unlock the regenerative potential innate to human tissues/organs in a state of deterioration and to restore or reestablish normal bodily function. Advances in our understanding of regenerative biomaterials and their roles in new tissue formation can potentially open a new frontier in the fast-growing field of regenerative medicine. Taking inspiration from the role and multi-component construction of native extracellular matrices (ECMs) for cell accommodation, the synthetic biomaterials produced today routinely incorporate biologically active components to define an artificial in vivo milieu with complex and dynamic interactions that foster and regulate stem cells, similar to the events occurring in a natural cellular microenvironment. The range and degree of biomaterial sophistication have also dramatically increased as more knowledge has accumulated through materials science, matrix biology and tissue engineering. However, achieving clinical translation and commercial success requires regenerative biomaterials to be not only efficacious and safe but also cost-effective and convenient for use and production. Utilizing biomaterials of human origin as building blocks for therapeutic purposes has provided a facilitated approach that closely mimics the critical aspects of natural tissue with regard to its physical and chemical properties for the orchestration of wound healing and tissue regeneration. In addition to directly using tissue transfers and transplants for repair, new applications of human-derived biomaterials are now focusing on the use of naturally occurring biomacromolecules, decellularized ECM scaffolds and autologous preparations rich in growth factors/non-expanded stem cells to either target acceleration/magnification of the body's own repair capacity or use nature's paradigms to create new tissues for restoration. In particular, there is increasing interest in separating ECMs into simplified functional domains and/or biopolymeric assemblies so that these components/constituents can be discretely exploited and manipulated for the production of bioscaffolds and new biomimetic biomaterials. Here, following an overview of tissue auto-/allo-transplantation, we discuss the recent trends and advances as well as the challenges and future directions in the evolution and application of human-derived biomaterials for reconstructive surgery and tissue engineering. In particular, we focus on an exploration of the structural, mechanical, biochemical and biological information present in native human tissue for bioengineering applications and to provide inspiration for the design of future biomaterials.

Therapeutic Effects of Umbilical Cord Blood Derived Mesenchymal Stem Cell-Conditioned Medium on Pulmonary Arterial Hypertension in Rats

Background:

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) may have multiple therapeutic applications for cell based therapy including the treatment of pulmonary artery hypertension (PAH). As low survival rates and potential tumorigenicity of implanted cells could undermine the mesenchymal stem cell (MSC) cell-based therapy, we chose to investigate the use of conditioned medium (CM) from a culture of MSC cells as a feasible alternative.

Methods:

CM was prepared by culturing hUCB-MSCs in three-dimensional spheroids. In a rat model of PAH induced by monocrotaline, we infused CM or the control unconditioned culture media via the tail-vein of 6-week-old Sprague-Dawley rats.

Results:

Compared with the control unconditioned media, CM infusion reduced the ventricular pressure, the right ventricle/(left ventricle+interventricular septum) ratio, and maintained respiratory function in the treated animals. Also, the number of interleukin 1α (IL-1α), chemokine (C-C motif) ligand 5 (CCL5), and tissue inhibitor of metalloproteinase 1 (TIMP-1)–positive cells increased in lung samples and the number of terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling technique (TUNEL)–positive cells decreased significantly in the CM treated animals.

Conclusions:

From our in vivo data in the rat model, the observed decreases in the TUNEL staining suggest a potential therapeutic benefit of the CM in ameliorating PAH-mediated lung tissue damage. Increased IL-1α, CCL5, and TIMP-1 levels may play important roles in this regard.

Dissection of the cord blood stromal component reveals predictive parameters for culture outcome

In regenerative medicine, human cord blood-derived multipotent mesenchymal stromal cells (CBMSCs) stand out for their biological peculiarities demonstrated in in vitro and in vivo preclinical studies. Here, we present our 9-year experience for the consistent isolation of CBMSCs. Although nearly one CB unit out of two retains the potential to give rise to MSC colonies, only 46% of them can be cultured till low passages (P≥4), but one-fourth of those reaches even higher passages (P≥8). Subsequent characterization for morphological, clonal, differentiation, and proliferation properties revealed two divergent CBMSC behaviors. In particular, a cumulative population doublings cut-off (CPD=15) was identified that undoubtedly distinguishes two growth curves, and different degrees of commitment toward osteogenesis were observed. These data clearly show the existence of at least two distinct CBMSC subsets: one mainly short-living and less proliferative (SL-CBMSCs), the other long-living, with higher growth rate, and, very importantly, with significantly (P≤0.01) longer telomere (LL-CBMSCs). Moreover, significant differences in the immunoprofile before seeding were found among CB units giving rise to LL-CBMSCs or SL-CBMSCs or showing no colony formation. Finally, all the aforementioned results provided a peculiar and useful set of parameters potentially predictive for CBMSC culture outcome.

Cartilage Repair Using Composites of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells and Hyaluronic Acid Hydrogel in a Minipig Model

The cartilage regeneration potential of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) with a hyaluronic acid (HA) hydrogel composite has shown remarkable results in rat and rabbit models. The purpose of the present study was to confirm the consistent regenerative potential in a pig model using three different cell lines. A full-thickness chondral injury was intentionally created in the trochlear groove of each knee in 6 minipigs. Three weeks later, an osteochondral defect, 5 mm wide by 10 mm deep, was created, followed by an 8-mm-wide and 5-mm-deep reaming. A mixture (1.5 ml) of hUCB-MSCs (0.5×10(7) cells per milliliter) and 4% HA hydrogel composite was then transplanted into the defect on the right knee. Each cell line was used in two minipigs. The osteochondral defect created in the same manner on the left knee was untreated to act as the control. At 12 weeks postoperatively, the pigs were sacrificed, and the degree of subsequent cartilage regeneration was evaluated by gross and histological analysis. The transplanted knee resulted in superior and more complete hyaline cartilage regeneration compared with the control knee. The cellular characteristics (e.g., cellular proliferation and chondrogenic differentiation capacity) of the hUCB-MSCs influenced the degree of cartilage regeneration potential. This evidence of consistent cartilage regeneration using composites of hUCB-MSCs and HA hydrogel in a large animal model could be a stepping stone to a human clinical trial in the future.

SIGNIFICANCE

To date, several studies have investigated the chondrogenic potential of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs); however, the preclinical studies are still limited in numbers with various results. In parallel, in the past several years, the cartilage regeneration potential of hUCB-MSCs with a hyaluronic acid (HA) hydrogel composite have been investigated and remarkable results in rat and rabbit models have been attained. (These experimental results are currently in preparation for publication.) Before applying the cartilage regeneration technique in a human clinical trial, it seemed necessary to confirm the consistent result in a larger animal model. At 12 weeks postoperatively, the minipigs were sacrificed, and the degree of subsequent cartilage regeneration was evaluated by gross and histological analysis. The transplanted knee resulted in superior and more complete hyaline cartilage regeneration compared with the control knee. This evidence of consistent cartilage regeneration with composites of hUCB-MSCs and HA hydrogel in a large animal model could be a stepping stone to a human clinical trial in the future.

Regenerative Therapy and Immune Modulation Using Umbilical Cord Blood-Derived Cells

Since the first cord blood transplantation in 1988, umbilical cord blood has become an important option as a source of cells for hematopoietic transplantation. Beyond its role in regenerating the blood and immune systems to treat blood diseases and inherited metabolic disorders, the role of nonhematopoietic progenitor cells in cord blood has led to new and emerging uses of umbilical cord blood in regenerative therapy and immune modulation. In this review, we provide an update on the clinical and preclinical studies using cord blood-derived cells such as mesenchymal stromal cells, endothelial-like progenitor cells, and others. We also provide insight on the use of cord blood cells as vehicles for the delivery of therapeutic agents through gene therapy and microvesicle-associated strategies. Moreover, cord blood can provide essential reagents for regenerative applications. Clinical activity using cord blood cells is increasing rapidly and this review aims to provide an important update on the tremendous potential within this fast-moving field.

Conditioned Media from Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Inhibits Melanogenesis by Promoting Proteasomal Degradation of MITF

Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) secrete various beneficial molecules, which have anti-apoptotic activity and cell proliferation. However, the effect of hUCB-MSCs in melanogenesis is largely unclear. In this study, we show that conditioned media (CM) derived from hUCB-MSCs inhibit melanogenesis by regulating microphthalmia-associated transcription factor (MITF) expression via the ERK signalling pathway. Treatment of hUCB-MSC-CM strongly inhibited the alpha-melanocyte stimulating hormone-induced hyperpigmentation in melanoma cells as well as melanocytes. Treatment of hUCB-MSC-CM induced ERK1/2 activation in melanocytes. In addition, inhibition of ERK1/2 suppressed the anti-pigmentation activity of the hUCB-MSC-CM in melanocytes and in vitro artificial skin models. We also found that the expression of MITF was appreciably diminished while expression of phosphorylated MITF, which leads to its proteasomal degradation, was increased in cells treated with hUCB-MSC-CM. These results suggested that hUCB-MSC-CM significantly suppresses melanin synthesis via MITF degradation by the ERK pathway activation.

Placenta-based therapies for the treatment of epidermolysis bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe blistering skin disease caused by mutations in the COL7A1 gene. These mutations lead to decreased or absent levels of collagen VII at the dermal-epidermal junction. Over the past decade, significant progress has been made in the treatment of RDEB, including the use of hematopoietic cell transplantation, but a cure has been elusive. Patients still experience life-limiting and life-threatening complications as a result of painful and debilitating wounds. The continued suffering of these patients drives the need to improve existing therapies and develop new ones. In this Review, we will discuss how recent advances in placenta-based, umbilical cord blood-based and amniotic membrane-based therapies may play a role in the both the current and future treatment of RDEB.

Effects of human umbilical cord mesenchymal stem cells on renal ischaemia-reperfusion injury in rats

OBJECTIVE

This study aims to observe the function of umbilical cord-mesenchymal stem cells (UC-MSCs) labelled with enhanced green fluorescent protein (eGFP) in the repair of renal ischaemia-reperfusion (I/R) injury, to determine the effects on inflammatory cascade in an established rat model and to explore possible pathogenesis.

MATERIALS AND METHODS

Sixty rats were randomly divided into three groups: the sham-operated, I/R and UC-MSC treatment groups. All rats underwent right nephrectomy. Ischaemia was induced in the left kidney by occlusion of the renal artery and vein for 1hour, followed by reperfusion for 24 hours or 48 hours. Kidney samples were collected to observe morphological changes. Immunohistochemistry was performed to assess the expression of intercellular adhesion molecule 1 (ICAM-1) in the renal tissue sample, as well as the number of infiltrating polymorphonuclear neutrophils (PMNLs) and UC-MSCs with positive eGFP.

RESULTS

Renal histopathological damages and the expression of ICAM-1 and PMNL increased significantly in the I/R group compared with those in the sham-operated group, whereas the damages were less conspicuous in the UC-MSC treatment group.

CONCLUSIONS

Renal ICAM-1, which mediated PMNL infiltration and contributed to renal damage, was significantly up-regulated in the I/R group. UC-MSCs were identified to inhibit these pathological processes and protect the kidney from I/R injury.

Mesenchymal stem cells are enriched in head neck squamous cell carcinoma, correlates with tumour size and inhibit T-cell proliferation

BACKGROUND

Cancer is a multifactorial disease not only restricted to transformed epithelium, but also involving cells of the immune system and cells of mesenchymal origin, particularly mesenchymal stem cells (MSCs). Mesenchymal stem cells contribute to blood- and lymph- neoangiogenesis, generate myofibroblasts, with pro-invasive activity and may suppress anti-tumour immunity.

METHODS

In this paper, we evaluated the presence and features of MSCs isolated from human head neck squamous cell carcinoma (HNSCC).

RESULTS

Fresh specimens of HNSCC showed higher proportions of CD90+ cells compared with normal tissue; these cells co-expressed CD29, CD105, and CD73, but not CD31, CD45, CD133, and human epithelial antigen similarly to bone marrow-derived MSCs (BM-MSCs). Adherent stromal cells isolated from tumour shared also differentiation potential with BM-MSCs, thus we named them as tumour-MSCs. Interestingly, tumour-MSCs showed a clear immunosuppressive activity on in vitro stimulated T lymphocytes, mainly mediated by indoelamine 2,3 dioxygenase activity, like BM-MSCs. To evaluate their possible role in tumour growth in vivo, we correlated tumour-MSC proportions with neoplasm size. Tumour-MSCs frequency directly correlated with tumour volume and inversely with the frequency of tumour-infiltrating leukocytes.

CONCLUSIONS

These data support the concept that tumour-MSCs may favour tumour growth not only through their effect on stromal development, but also by inhibiting the anti-tumour immune response.

A decline in Wnt3a signaling is necessary for mesenchymal stem cells to proceed to replicative senescence

Umbilical cord blood-derived mesenchymal stem cells are a promising source of cells for regeneration therapy due to their multipotency, high proliferative capacity, relatively noninvasive collection, and ready availability. However, extended cell culture inevitably triggers cellular senescence-the irreversible arrest of cell division-thereby limiting the proliferative lifespan of adult stem cells. Wnt/β-catenin signaling plays a functional role as a key regulator of self-renewal and differentiation in mesenchymal stem cells (MSCs), and thus Wnt/β-catenin signaling and cellular senescence might be closely connected. Here, we show that the expression levels of canonical Wnt families decrease as MSCs age during subculture. Activation of the Wnt pathway by treatment with Wnt3a-conditioned medium or glycogen synthase kinase 3β inhibitors, such as SB-216763 and 6-bromoindirubin-3'-oxime, delays the progression of cellular senescence as shown by the decrease in the senescence effectors p53 and pRb, lowered senescence-associated β-galactosidase activity, and increased telomerase activity. In contrast, suppression of the Wnt pathway by treatment with dickkopf-1 (an antagonist of the Wnt coreceptor) and β-catenin siRNA transfection promotes senescence in MSCs. Interestingly, the magnitude of the response to enhanced Wnt3a/β-catenin signaling appears to depend on the senescent state during extended culture, particularly after multiple passages. These results suggest that Wnt3a signaling might be a predominant factor that could be used to overcome senescence in long-term cultured MSCs by directly intervening in the proliferative capacity and MSC senescence. The functional role of Wnt3a/β-catenin signaling in hedging cellular senescence may allow the development of new approaches for stem cell-based therapies.

Effect of preemptive treatment with human umbilical cord blood-derived mesenchymal stem cells on the development of renal ischemia-reperfusion injury in mice

Human umbilical cord blood-derived mesenchymal stem cells (HUCB-MSCs) have been studied in several models of immune-mediated disease because of their unique immunomodulatory properties. We hypothesized that HUCB-MSCs could suppress the inflammatory response in postischemic kidneys and attenuate early renal injury. In 8- to 10-wk-old male C57BL/6 mice, bilateral ischemia-reperfusion injury (IRI) surgery was performed, and 1 × 10(6) HUCB-MSCs were injected intraperitoneally 24 h before surgery and during reperfusion. Renal functional and histological changes, HUCB-MSC trafficking, leukocyte infiltration, and cytokine expression were analyzed. Renal functional decline and tubular injury after IRI were attenuated by HUCB-MSC treatment. PKH-26-labeled HUCB-MSCs trafficked into the postischemic kidney. Although numbers of CD45-positive leukocytes in the postischemic kidney were comparable between groups, the expression of interferon-γ in the postischemic kidney was suppressed by HUCB-MSC treatment. The rapid decrease in intrarenal VEGF after IRI was markedly mitigated by HUCB-MSC treatment. In inflammatory conditions simulated in a cell culture experiment, VEGF secretion from HUCB-MSCs was substantially enhanced. VEGF inhibitor abolished the renoprotective effect of HUCB-MSCs after IRI. Flow cytometry analysis revealed the decreased infiltration of natural killer T cells and increased number of regulatory T cells in postischemic kidneys. In addition, these effects of HUCB-MSCs on kidney infiltrating mononuclear cells after IRI were attenuated by VEGF inhibitor. HUCB-MSCs attenuated renal injury in mice in the early injury phase after IRI, mainly by humoral effects and secretion of VEGF. Our results suggest a promising role for HUCB-MSCs in the treatment of renal IRI.

Intraarterial transplantation of human umbilical cord blood mononuclear cells is more efficacious and safer compared with umbilical cord mesenchymal stromal cells in a rodent stroke model

INTRODUCTION

Stroke is the second leading cause of death worldwide, claims six lives every 60 seconds, and is a leading cause of adult disability across the globe. Tissue plasminogen activator, the only United States Food and Drug Administration (FDA)-approved drug currently available, has a narrow therapeutic time window of less than 5 hours. In the past decade, cells derived from the human umbilical cord (HUC) have emerged as a potential therapeutic alternative for stroke; however, the most effective HUC-derived cell population remains unknown.

METHODS

We compared three cell populations derived from the human umbilical cord: cord blood mononuclear cells (cbMNCs); cord blood mesenchymal stromal cells (cbMSCs), a subpopulation of cbMNCs; and cord matrix MSCs (cmMSCs). We characterized these cells in vitro with flow cytometry and assessed the cells' in vivo efficacy in a 2-hour transient middle cerebral artery occlusion (MCAo) rat model of stroke. cbMNCs, cbMSCs, and cmMSCs were each transplanted intraarterially at 24 hours after stroke.

RESULTS

A reduction in neurologic deficit and infarct area was observed in all three cell groups; however, this reduction was significantly enhanced in the cbMNC group compared with the cmMSC group. At 2 weeks after stroke, human nuclei-positive cells were present in the ischemic hemispheres of immunocompetent stroke rats in all three cell groups. Significantly decreased expression of rat brain-derived neurotrophic factor mRNA was observed in the ischemic hemispheres of all three cell-treated and phosphate-buffered saline (PBS) group animals compared with sham animals, although the decrease was least in cbMNC-treated animals. Significantly decreased expression of rat interleukin (IL)-2 mRNA and IL-6 mRNA was seen only in the cbMSC group. Notably, more severe complications (death, eye inflammation) were observed in the cmMSC group compared with the cbMNC and cbMSC groups.

CONCLUSIONS

All three tested cell types promoted recovery after stroke, but cbMNCs showed enhanced recovery and fewer complications compared with cmMSCs.