Delivery Of Mesenchymal Stem Cells Research Articles

Material Properties and Cell Compatibility of Photo-Crosslinked Sericin Urethane Methacryloyl Hydrogel.

There is a need to develop novel cytocompatible hydrogels for cell encapsulation and delivery in regenerative medicine. The objective of this work was to synthesize isocyanato ethyl methacryloyl-functionalized sericin and determine its material properties as a natural hydrogel for the encapsulation and delivery of human mesenchymal stem cells (MSCs) in regenerative medicine. Sericin extracted from silk cocoons was reacted with 2-isocyanatoethyl methacrylate (IEM) or methacrylic anhydride (MA) to produce sericin urethane methacryloyl (SerAte-UM) or sericin methacryloyl (SerAte-M, control) biopolymers, respectively. The hydrogels produced by photo-crosslinking of the biopolymers in an aqueous solution were characterized with respect to gelation kinetics, microstructure, compressive modulus, water content, degradation, permeability, and viability of encapsulated cells. The secondary structure of citric acid-extracted sericin was not affected by functionalization with IEM or MA. SerAte-UM hydrogel was slightly more hydrophilic than SerAte-M. The gelation time of SerAte-UM hydrogel decreased with an increasing degree of modification. The photo-polymerized SerAte-UM hydrogel had a highly porous, fibrous, honeycomb microstructure with an average pore size in the 40–50 µm range. The compressive modulus, swelling ratio, and permeability of SerAte-UM hydrogel depended on the degree of modification of sericin, and the mass loss after 21 days of incubation in aqueous solution was <25%. Both SerAte-UM and SerAte-M hydrogels supported viability and growth in encapsulated MSCs. The SerAte-UM hydrogel, with its higher hydrophilicity compared to SerAte-M, is promising as a matrix for encapsulation and delivery of stem cells in tissue engineering.

Low temperature hybrid 3D printing of hierarchically porous bone tissue engineering scaffolds with in situ delivery of osteogenic peptide and mesenchymal stem cells

Compared to other conventional scaffold fabrication techniques, three-dimensional (3D) printing is advantageous in producing bone tissue engineering scaffolds with customized shape, tailored pore size/porosity, required mechanical properties and even desirable biomolecule delivery capability. However, for scaffolds with a large volume, it is highly difficult to get seeded cells to migrate to the central region of the scaffolds, resulting in an inhomogeneous cell distribution and therefore lowering the bone forming ability. To overcome this major obstacle, in this study, cell-laden bone tissue engineering scaffolds consisting of osteogenic peptide (OP) loaded β-tricalcium phosphate (TCP)/poly(lactic-co-glycolic acid) (PLGA) (OP/TCP/PLGA, designated as OTP) nanocomposite struts and rat bone marrow derived mesenchymal stem cell (rBMSC)-laden gelatin/GelMA hydrogel rods were produced through ‘dual-nozzle’ low temperature hybrid 3D printing. The cell-laden scaffolds exhibited a bi-phasic structure and had a mechanical modulus of about 19.6 MPa, which was similar to that of human cancellous bone. OP can be released from the hybrid scaffolds in a sustained manner and achieved a cumulative release level of about 78% after 24 d. rBMSCs encapsulated in the hydrogel rods exhibited a cell viability of about 87.4% right after low temperature hybrid 3D printing and could be released from the hydrogel rods to achieve cell anchorage on the surface of adjacent OTP struts. The OP released from OTP struts enhanced rBMSCs proliferation. Compared to rBMSC-laden hybrid scaffolds without OP incorporation, the rBMSC-laden hybrid scaffolds incorporated with OP significantly up-regulated osteogenic differentiation of rBMSCs by showing a higher level of alkaline phosphatase expression and calcium deposition. This ‘proof-of-concept’ study has provided a facile method to form cell-laden bone tissue engineering scaffolds with not only required mechanical strength, biomimetic structure and sustained biomolecule release profile but also excellent cell delivery capability with uniform cell distribution, which can improve the bone forming ability in the body.

Biostimulatory Micro-Fragmented Nanofiber-Hydrogel Composite Improves Mesenchymal Stem Cell Delivery and Soft Tissue Remodeling.

Functional microgels are preferred stem cell carriers due to the ease of delivery through minimally invasive injection and seamless integration with the surrounding host tissue. A biostimulatory nanofiber-hydrogel composite (NHC) has been previously developed through covalently crosslinking a hyaluronic acid hydrogel network with surface-functionalized poly (ε-caprolactone) nanofiber fragments. The NHC mimics the microarchitecture of native soft tissue matrix, showing enhanced cell infiltration, immunomodulation, and proangiogenic properties. Here, injectability of the pre-formed NHC is improved by mechanical fragmentation, making it into micro-fragmented NHC (mfNHC) in a granular gel form as a stem cell carrier to deliver mesenchymal stem cells (MSCs) for soft tissue remodeling. The mfNHC shows a similar storage modulus but a significantly reduced injection force, as compared with the corresponding bulk NHC. When injected subcutaneously in a rat model, mfNHC-MSC constructs initiate an elevated level of host macrophage infiltration, more pro-regenerative polarization, and subsequently, improved angiogenesis and adipogenesis response when compared to mfNHC alone. A similar trend of host cell infiltration and pro-angiogenic response is detected in a swine model with a larger volume injection. These results suggest a strong potential for use of the mfNHC as an injectable carrier for cell delivery and soft tissue remodeling.

3D Living Dressing Improves Healing and Modulates Immune Response in a Thermal Injury Model.

Thermal injury trauma can induce a state of immunosuppression, causing wounds to become chronic in nature. Stem cell-based therapies represent a promising new approach to treat such wounds due to their capacity to self-renew and their multi-lineage potential. Mesenchymal stem cells (MSCs) are known to secrete endogenous factors that stimulate wound healing by promoting angiogenesis, extracellular matrix remodeling, skin regeneration, and by dampening down inflammation. MSC delivery in a biomaterial construct can augment their wound-healing capacity by concentrating cells at the burn site and upregulating trophic factor secretion. The work presented is the first to evaluate repair in an in vitro raft thermal injury model using a regenerative, dual cell delivery three-dimensional (3D) core/shell (c/s) "living dressing" construct. This previously characterized 3D c/s bioprinted construct, which delivers both MSCs and endothelial cells, was used to treat an in vitro 3D raft skin thermal injury wound model. The mesenchymal stromal cell line (T0523) was encapsulated within a gelatin-based shell bioink, and human umbilical vein endothelial cells within a chitosan-based core bioink to biofabricate a living dressing for enhanced thermal injury repair and regeneration. We hypothesized that the cell-laden c/s tissue engineered construct (TEC) would strengthen the wound's proangiogenic, anti-inflammatory, and skin regeneration potential. An in vitro thermal injury in a 3D raft skin model showed a slight delay in wound closure in the presence of the c/s TEC but was augmented by corresponding increases in the release of wound-healing factors, epidermal growth factor, matrix metalloproteinases-9, transforming growth factor-α, platelet-derived growth factor; a decrease in pro-inflammatory factor interleukin-6, and evidence of neovascularization.

Mesenchymal stem cells target microglia via galectin-1 production to rescue aged mice from olfactory dysfunction

Olfactory loss has been considered as the earliest complication for the aging process while underlying mechanisms and therapeutic strategies remain unclear. Given the correlation between microglial activation and olfactory dysfunction, here we investigated whether the immunomodulatory action of mesenchymal stem cells (MSCs) can rescue the olfactory impairment in old mice. The intranasal delivery of MSCs limited microglial activation and neuronal apoptosis in the olfactory bulb (OB), leading to improvement in olfaction. MSCs down-regulated the proportion of CD86+ microglia and prevented the maturation of cathepsin S, one of the inflammatory mediators in olfactory impairment, via the suppression of p38 MAPK signaling. Notably, old astrocytes could not prevent excessive microgliosis because the endogenous production of Galectin-1 (Gal1), one of the key microglia regulators secreted by astrocytes, was not sufficiently upregulated in the aged brain despite the presence of reactive astrogliosis. Considering that Gal1 is known as a potent paracrine factor of MSCs, we investigated whether MSC-derived Gal1 could compensate for defective astrocyte function in terms of microglial regulation. MSCs and their culture supernatant (MSC-CM) could regulate the direction of microglial differentiation by impeding the polarization towards the pro-inflammatory M1 type; notably, a selective Gal1 inhibitor OTX008 could hinder this phenomenon, indicating that Gal1 is involved in immunomodulation exerted by MSCs. Also, acute microglial activation within the OB upon LPS infusion was attenuated by MSC-CM in a Gal1-dependent manner. Our study demonstrates the therapeutic benefit of MSCs on age-related olfactory dysfunction and suggests Gal1 as a key mediator of the anti-inflammatory action of MSCs.

Mesenchymal stem cells exert their anti-asthmatic effects through macrophage modulation in a murine chronic asthma model

Despite numerous previous studies, the full action mechanism of the pathogenesis of asthma remains undiscovered, and the need for further investigation is increasing in order to identify more effective target molecules. Recent attempts to develop more efficacious treatments for asthma have incorporated mesenchymal stem cell (MSC)-based cell therapies. This study aimed to evaluate the anti-asthmatic effects of MSCs primed with Liproxstatin-1, a potent ferroptosis inhibitor. In addition, we sought to examine the changes within macrophage populations and their characteristics in asthmatic conditions. Seven-week-old transgenic mice, constitutively overexpressing lung-specific interleukin (IL)-13, were used to simulate chronic asthma. Human umbilical cord-derived MSCs (hUC-MSCs) primed with Liproxstatin-1 were intratracheally administered four days prior to sampling. IL-13 transgenic mice demonstrated phenotypes of chronic asthma, including severe inflammation, goblet cell hyperplasia, and subepithelial fibrosis. Ly6C+M2 macrophages, found within the pro-inflammatory CD11c+CD11b+ macrophages, were upregulated and showed a strong correlation with lung eosinophil counts. Liproxstatin-1-primed hUC-MSCs showed enhanced ability to downregulate the activation of T helper type 2 cells compared to naïve MSCs in vitro and reduced airway inflammation, particularly Ly6C+M2 macrophages population, and fibrosis in vivo. In conclusion, intratracheal administration is an effective method of MSC delivery, and macrophages hold great potential as an additional therapeutic target for asthma.

Equine Platelet Lysate Gel: A Matrix for Mesenchymal Stem Cell Delivery.

A variety of bioscaffolds have been developed as carriers for the delivery of mesenchymal stem cells (MSCs), however, many of them are unable to provide direct cell nourishment, a critical factor for survival and retention of MSCs at the site of delivery. Platelet lysate is a plasma-derived product rich in growth factors that can be turned into a gel matrix following the addition of calcium chloride. Our objective was to characterize growth factor and cytokine release of equine platelet lysate gel (ePL gel) encapsulated with MSCs over time and to measure the viability and proliferation of ePL gel-encapsulated MSCs for up to 14 days. The release of interleukin-1β (IL-1β), interleukin-10 (IL-10), transforming growth factor beta (TGF-β), vascular endothelial growth factor (VEGF), and platelet-derived growth factor BB (PDGF-BB), as well as fibrinogen degradation, were measured from ePL gel with and without equine bone marrow-derived MSCs and compared with MSCs in monolayer. MSC proliferation and viability within the gel were assessed up to 14 days. Compared with monolayer MSC cultures, significantly higher concentrations of IL-1β, IL-10, and TGF-β were measured from supernatants collected from ePL gel containing MSCs at various time points. Significantly lower concentrations of PDGF-BB were measured in the supernatant when MSCs were incorporated in ePL gel while VEGF tended to be increased compared with MSCs in monolayer. Incorporation in ePL gel for up to 14 days did not appear to affect viability and proliferation rates of MSCs as these were found to be similar to those measured in monolayer cell culture. ePL gel may have the potential to serve as bioscaffold for MSC delivery since it appears to support the proliferation and viability of MSCs for up to 14 days.

RGD-Hydrogel Improves the Therapeutic Effect of Bone Marrow-Derived Mesenchymal Stem Cells on Phosgene-Induced Acute Lung Injury in Rats

Mesenchymal stem cells (MSCs) have promising potential in the treatment of various diseases, such as the therapeutic effect of bone marrow-derived MSCs for phosgene-induced acute lung injury (P-ALI). However, MSC-related therapeutics are limited due to poor cell survival, requiring appropriate MSC delivery systems to maximise therapeutic capacity. Biomaterial RGD-hydrogel is a potential cell delivery vehicle as it can mimic the natural extracellular matrix and provide cell adhesion support. The application of RGD-hydrogel in the MSC treatment of respiratory diseases is scarce. This study reports that RGD-hydrogel has good biocompatibility and can increase the secretion of Angiopoietin-1, hepatocyte growth factor, epidermal growth factor, vascular endothelial cell growth factor, and interleukin-10 in vitro MSCs. The hydrogel-encapsulated MSCs could further alleviate P-ALI and show better cell survival in vivo. Overall, RGD-hydrogel could improve the MSC treatment of P-ALI by modulating cell survival and reparative activities. It is exciting to see more and more ways to unlock the therapeutic potential of MSCs.

Biomimic Trained Immunity-MSCs Delivery Microcarriers for Acute Liver Failure Regeneration.

Mesenchymal stem cells (MSCs) have a demonstrated value for acute liver failure (ALF) regeneration, while their delivery stratagems with long-term biological functions, low immune response, and high biocompatibility are still a challenge. Here, a lipopolysaccharide (LPS)-loaded photoresponsive cryogel porous microcarrier (CPM) for MSCs delivery and colonization is presented to promote defect liver regeneration. The CPMs are fabricated with graphene oxide, poly(N-isopropylacrylamide), and gelatin methacrylate (GelMA) via droplet microfluidic technology and a gradient-cooling procedure. Benefitting from the biocompatible GelMA component and the porous microstructure of the CPMs, MSCs can be nondestructively captured and abundantly delivered. Because the LPS can be released from the CPMs under NIR irradiation, the delivered MSCs are imparted with the feature of "trained immunity." Thus, when the MSCs-laden CPMs are tailored into the liver matched patches by bioprinting and applied in ALF rats, they display superior anti-inflammatory and more significant liver regeneration properties than the untrained MSCs. These features make the CPMs an excellent MSCs delivery system for clinical applications in tissue repair.

Competitive Hybridization of a Microarray Identifies CMKLR1 as an Up-Regulated Gene in Human Bone Marrow-Derived Mesenchymal Stem Cells Compared to Human Embryonic Fibroblasts.

Mesenchymal stem cells (MSCs) have been widely applied to the regeneration of damaged tissue and the modulation of immune response. The purity of MSC preparation and the delivery of MSCs to a target region are critical factors for success in therapeutic application. In order to define the molecular identity of an MSC, the gene expression pattern of a human bone marrow-derived mesenchymal stem cell (hBMSC) was compared with that of a human embryonic fibroblast (hEF) by competitive hybridization of a microarray. A total of 270 and 173 genes were two-fold up- and down-regulated with FDR < 0.05 in the hBMSC compared to the hEF, respectively. The overexpressed genes in the hBMSC over the hEF, including transcription factors, were enriched for biological processes such as axial pattern formation, face morphogenesis and skeletal system development, which could be expected from the differentiation potential of MSCs. CD70 and CD339 were identified as additional CD markers that were up-regulated in the hBMSC over the hEF. The differential expression of CD70 and CD339 might be exploited to distinguish hEF and hBMSC. CMKLR1, a chemokine receptor, was up-regulated in the hBMSC compared to the hEF. RARRES2, a CMKLR1 ligand, stimulated specific migration of the hBMSC, but not of the hEF. RARRES2 manifested as ~two-fold less effective than SDF-1α in the directional migration of the hBMSC. The expression of CMKLR1 was decreased upon the osteoblastic differentiation of the hBMSC. However, the RARRES2-loaded 10% HA-silk scaffold did not recruit endogenous cells to the scaffold in vivo. The RARRES2–CMKLR1 axis could be employed in recruiting systemically delivered or endogenous MSCs to a specific target lesion.

Intraperitoneally Delivered Mesenchymal Stem Cells Alleviate Experimental Colitis Through THBS1-Mediated Induction of IL-10-Competent Regulatory B Cells

Mesenchymal stem cells (MSCs) show promising therapeutic potential in treating inflammatory bowel disease (IBD), and intraperitoneal delivery of MSCs have become a more effective route for IBD treatment. However, the underlying mechanisms are still poorly understood. Here, we found that intraperitoneally delivered MSCs significantly alleviated experimental colitis. Depletion of peritoneal B cells, but not macrophages, clearly impaired the therapeutic effects of MSCs. Intraperitoneally delivered MSCs improved IBD likely by boosting the IL-10-producing B cells in the peritoneal cavity, and a single intraperitoneal injection of MSCs could significantly prevent disease severity in a recurrent mouse colitis model, with lower proinflammation cytokines and high level of IL-10. The gene expression profile revealed that thrombospondin-1 (THBS1) was dramatically upregulated in MSCs after coculture with peritoneal lavage fluid from colitis mice. Knockout of THBS1 expression in MSCs abolished their therapeutic effects in colitis and the induction of IL-10-producing B cells. Mechanistically, THBS1 modulates the activation of transforming growth factor-β (TGF-β), which combines with TGF-β receptors on B cells and contributes to IL-10 production. Blocking the interaction between THBS1 and latent TGF-β or inhibiting TGF-β receptors (TGF-βR) significantly reversed the THBS1-mediated induction of IL-10-producing B cells and the therapeutic effects on colitis. Collectively, our study revealed that intraperitoneally delivered MSCs secreted THBS1 to boost IL-10+Bregs and control the progression and recurrence of colitis, providing new insight for the prevention and treatment of IBD.

Mesenchymal Stem Cells Delivery in Individuals with Different Pathologies: Multimodal Tracking, Safety and Future Applications

Due to their ease of isolation and their properties, mesenchymal stem cells (MSCs) have been widely investigated. MSCs have been proved capable of migration towards areas of inflammation, including tumors. Therefore, they have been suggested as vectors to carry therapies, specifically to neoplasias. As most of the individuals joining clinical trials that use MSCs for cancer and other pathologies are carefully recruited and do not suffer from other diseases, here we decided to study the safety and application of iv-injected MSCs in animals simultaneously induced with different inflammatory pathologies (diabetes, wound healing and tumors). We studied this by in vitro and in vivo approaches using different gene reporters (GFP, hNIS, and f-Luc) and non-invasive techniques (PET, BLI, or fluorescence). Our results found that MSCs reached different organs depending on the previously induced pathology. Moreover, we evaluated the property of MSCs to target tumors as vectors to deliver adenoviruses, including the interaction between tumor microenvironment and MSCs on their arrival. Mechanisms such as transdifferentiation, MSC fusion with cells, or paracrine processes after MSCs homing were studied, increasing the knowledge and safety of this new therapy for cancer.

P407 A Phase IB/IIA study of remestemcel-L, an allogeneic bone marrow derived mesenchymal stem cell product, for the treatment of medically refractory ulcerative colitis: An interim analysis

Abstract Background Direct injection of mesenchymal stem cells (MSCs) have been used for the treatment of perianal Crohn’s fistulizing disease. However, no studies have looked at the direct injection of MSCs for luminal ulcerative colitis (UC). Methods Following screening and informed consent, patients with medically refractory UC were randomized in a, 2:1 fashion to receive remestemcel-L, an ex vivo expanded allogeneic bone marrow derived MSC product, at a dose of, 150 or, 300 million MSCs versus placebo delivered via direct injection using a, 23 G sclerotherapy needle at the time of colonoscopy. Patients were included if they had medically refractory UC defined as an established diagnosis for at least, 6 months prior to study enrollment and had lost response to at least one monoclonal antibody in the past. Patients were evaluated with validated clinical and endoscopic scoring systems at, 2 weeks, 6 weeks, and, 3 months post MSC delivery. Patients randomized to control crossed over at, 3 months to receive MSC treatment and followed the same schedule for post MSC evaluation. Results A total of six patients were enrolled and treated;, 4 were randomized to treatment and, 2 to placebo. All had been on prior anti-TNF or anti integrin-therapy. There were no adverse and serious adverse events related to investigational product. In the treatment group (n=4), the Mayo score and Mayo endoscopic severity score decreased in all patients by two weeks after MSC delivery. By six weeks post MSC treatment, all treated patients had achieved clinical and endoscopic remission as defined by the Mayo score and Mayo endoscopic severity score. Patient reported number of daily bowel movements decreased as did urgency and presence of blood in the stool. With regard to patient reported outcomes, at three months, based on the inflammatory bowel disease patient reported treatment impact (IBD-PRTI), all patients were extremely satisfied or satisfied with their MSC treatment. Treated response was described as excellent or good in all patients. In the control group (n=2), the Mayo score did not decrease. Patient reported number of daily bowel movements increased as did the number reporting blood in their stool; urgency remained unchanged. With regard to patient reported outcomes, at three months, based on the IBD-PRTI, one patient was neutral, and one patient was dissatisfied. Treated response was described as poor or unchanged in control patients. Conclusion MSCs offer a safe alternative therapeutic for the treatment of medically refractory UC. Early data suggests improved clinical and endoscopic scores by as early as two weeks following MSC delivery.

Safety and efficacy of transcoronary transfer of human neonatal stem cells to ischemic myocardium using a novel cell-delivery system (CIRCULATE catheter) in swine model of acute myocardial infarction.

Stem cell-based therapies have shown promise in adults with ischemic cardiomyopathy and children with congenital heart diseases, especially those without available therapeutic options. Human neonatal mesenchymal stem cells (nMSCs) have greater regenerative potential than adult stem cells. To describe our experience with a novel catheter system for transcoronary delivery of cell-based therapies (CIRCULATE catheter) in the intra-coronary delivery of nMSCs in a swine acute myocardial infarct model. A newly developed catheter system (CIRCULATE catheter) with several unique features, including an expandable intra-coronary reservoir with spirally placed side holes of varying diameter, was used. nMSCs together with their secretome were used for the treatment. Pigs underwent myocardial infarction by inflating a 2.5 mm angioplasty balloon in the left anterior descending artery for 60 min. After reperfusion, stem cell therapy or placebo was administered via the novel catheter. TTE was performed at baseline, 1 h after the procedure, and before the euthanasia. Troponin blood concertation was evaluated at baseline, and after 48 h. The heart was harvested, sliced, and stained with triphenyl tetrazolium chloride (TTC). Infarct size to area-at-risk ratio was calculated. Troponin was assessed at baseline and after 48 h. Thirty-nine pigs were operated with the mortality rate of 5.13% (exclusively malignant arrhythmia). Infarct size to area-at-risk ratio was significantly lower in the treatment group. Treated animals had higher ejection fraction than controls. Intra-coronary delivery of neonatal mesenchymal stem cells reduces the infarct size and restores myocardial function in a swine model. The novel catheter system (CIRCULATE catheter) tested in this study was safe and effective in transcoronary cell delivery of human neonatal mesenchymal stem cells.

Therapeutic mechanisms and routes of delivery of mesenchymal stem cells in veterinary medicine: A point of view

Mesenchymal stem cells (MSCs) represent an important tool in veterinary regenerative medicine due to their ability to home to injury sites and secrete molecules that regulate niches into regenerative microenvironments. Successful cell therapy depends on many factors, including choice of administration route and application of understanding of cell potency and their therapeutic mechanisms. In this point of view, the authors leverage the tumultuous history of the field to demonstrate the need for clinicians to continually update themselves as new discoveries are made in order to avoid misalignments in the future, especially regarding administration routes and dose frequency, as well as to explore recent insights into MSC plasticity, therapeutic mechanisms, and cell delivery systems.

Optimal Delivery Route of Mesenchymal Stem Cells for Cardiac Repair: The Path to Good Clinical Practice.

Research has shown that mesenchymal stem cells (MSCs) could be a promising therapy for treating progressive heart disease. However, translation into clinics efficiently and successfully has proven to be much more complicated. Many questions remain for optimizing treatment. Application method influences destiny of MSCs and afterwards impacts results of procedure, yet there is no general agreement about most suitable method of MSC delivery in the clinical setting. Herein, we explain principle of most-frequent MSCs delivery techniques in cardiology. This chapter summarizes crucial translational obstacles of clinical employment of MSCs for cardiac repair when analysed trough a prism of latest research centred on different techniques of MSCs application.

Using Platelet-Rich Plasma Hydrogel to Deliver Mesenchymal Stem Cells into Three-Dimensional PLGA Scaffold for Cartilage Tissue Engineering.

The synthetic biodegradable polyester-based rigid porous scaffolds and cell-laden hydrogels have been separately employed as therapeutic modality for cartilage repair. However, the synthetic rigid scaffolds alone may be limited due to the inherent lack of bioactivity for cartilage regeneration, while the hydrogels have insufficient mechanical properties that are not ideal for load-bearing cartilage applications. In the present study, a hybrid construct was designed to merge the advantage of 3D-printed rigid poly(lactic-co-glycolic acid) (PLGA) scaffolds with cell-laden platelet-rich plasma (PRP) hydrogels that can release growth factors to regulate the tissue healing process. PRP hydrogels potentially achieved the effective delivery of mesenchymal stem cells (MSCs) into PLGA scaffolds. This hybrid construct could obtain adequate mechanical properties and independently provide MSCs with appropriate clues for proliferation and differentiation. Real-time gene expression analysis showed that PRP stimulated both chondrogenic and osteogenic differentiation of MSC seeding into PLGA scaffolds. Finally, the hybrid constructs were implanted into rabbits to simultaneously regenerate both articular cartilage and subchondral bone within osteochondral defects. Our findings suggest that this unique hybrid system could be practically applied for osteochondral regeneration due to its capacity for cell transportation, growth factors release, and excellent mechanical strength, which would greatly contribute to the progress of cartilage tissue engineering.

Adipose Tissue-Derived Mesenchymal Stem Cells as a Potential Restorative Treatment for Cartilage Defects: A PRISMA Review and Meta-Analysis.

Cartilage defects are a predisposing factor for osteoarthritis. Conventional therapies are mostly palliative and there is an interest in developing newer therapies that target the disease’s progression. Mesenchymal stem cells (MSCs) have been suggested as a promising therapy to restore hyaline cartilage to cartilage defects, though the optimal cell source has remained under investigation. A PRISMA systematic review was conducted utilising five databases (MEDLINE, EMBASE, Cochrane Library, Scopus, Web of Science) which identified nineteen human studies that used adipose tissue-derived MSC (AMSC)-based therapies, including culture-expanded AMSCs and stromal vascular fraction, to treat cartilage defects. Clinical, imaging and histological outcomes, as well as other relevant details pertaining to cartilage regeneration, were extracted from each study. Pooled analysis revealed a significant improvement in WOMAC scores (mean difference: −25.52; 95%CI (−30.93, −20.10); p < 0.001), VAS scores (mean difference: −3.30; 95%CI (−3.72, −2.89); p < 0.001), KOOS scores and end point MOCART score (mean: 68.12; 95%CI (62.18, 74.05)), thus showing improvement. The studies in this review demonstrate the safety and efficacy of AMSC-based therapies for cartilage defects. Establishing standardised methods for MSC extraction and delivery, and performing studies with long follow-up should enable future high-quality research to provide the evidence needed to bring AMSC-based therapies into the market.

Abstract 12993: Administration of Echogenic Immunoliposome-Targeted CD146 + Mesenchymal Stem Cells Reduces Hypercholesterolemia and Atherosclerosis

Introduction and Hypothesis: Mesenchymal stem cells (MSC) have been used to treat atherosclerosis and diabetes in animal studies and clinical trials. We developed a nanotechnology in which MSC can be targeted with anti-CD146/ICAM bifunctional (BF) echogenic immunoliposomes (ELIP) for treatment of atherosclerosis. Here, we tested the hypothesis that BF-ELIP targeted MSC therapy is biologically safe and effective for preventing hypercholesterolemia and atheroma. Methods and Results: BF-ELIP with antibodies to the mesenchymal marker CD146 and the adhesion protein ICAM-1 were mixed with CD146 + MSC grown from adipose tissue of green fluorescence protein (GFP)-transgenic mice. The BF-ELIP/MSC mixtures or controls, such as non-immune ELIP (NE)/MSC mixtures, NE and MSC alone, were intravenously administered to C57BL/6J wild type (WT) and apolipoprotein-E deficient (ApoE -/- ) mice, which were age-/sex-matched. In a nearly 4 months followup, all the mice survived the ELIP/MSC injection without major adverse effects observed. No major difference in blood pressure was found between ELIP/MSC-treated and non-MSC controls. Total cholesterol and glucose were examined in blood samples collected from the animals. ApoE -/- mice developed significantly higher cholesterol (p&lt;0.05) but lower glucose (p&lt;0.05) levels than WT mice. The BF-ELIP targeted MSC injection reduced levels of total cholesterol and, to a lesser extent, glucose (p&lt;0.05). Non-invasive ultrasound confirmed enhancement of ELIP echogenicity and imaging of atheroma. Fluorescence microscopy illustrated GFP expression in the MSC mixtures and the arterial wall with atheroma. H&amp;E and Oil-Red O staining showed reduced plaque formation and lipid loading in the arterial wall of ApoE -/- but not WT mice with the MSC delivery. Conclusions: Administration of BF-ELIP targeted MSCs appears to be a safe, effective procedure, which may mitigate hypercholesterolemia and atherogenesis.

Rolling circle amplification (RCA)-based DNA hydrogel.

DNA hydrogels have unique properties, including sequence programmability, precise molecular recognition, stimuli-responsiveness, biocompatibility and biodegradability, that have enabled their use in diverse applications ranging from material science to biomedicine. Here, we describe a rolling circle amplification (RCA)-based synthesis of 3D DNA hydrogels with rationally programmed sequences and tunable physical, chemical and biological properties. RCA is a simple and highly efficient isothermal enzymatic amplification strategy to synthesize ultralong single-stranded DNA that benefits from mild reaction conditions, and stability and efficiency in complex biological environments. Other available methods for synthesis of DNA hydrogels include hybridization chain reactions, which need a large amount of hairpin strands to produce DNA chains, and PCR, which requires temperature cycling. In contrast, the RCA process is conducted at a constant temperature and requires a small amount of circular DNA template. In this protocol, the polymerase phi29 catalyzes the elongation and displacement of DNA chains to amplify DNA, which subsequently forms a 3D hydrogel network via various cross-linking strategies, including entanglement of DNA chains, multi-primed chain amplification, hybridization between DNA chains, and hybridization with functional moieties. We also describe how to use the protocol for isolation of bone marrow mesenchymal stem cells and cell delivery. The whole protocol takes ~2 d to complete, including hydrogel synthesis and applications in cell isolation and cell delivery.