Towards Reaching the Target: Clinical Application of Mesenchymal Stem Cells for Diabetic Foot Ulcers

Effectiveness of Stem Cell Therapy for Diabetic Foot Ulcers: A Systematic Review and GRADE Compliant Bootstrapped Meta-Analysis of Randomized Clinical Trials

Diabetic foot (DF) represents a severe complication of diabetes mellitus, imposing substantial psychological and economic burdens on affected individuals. This investigation sought to assess the therapeutic efficacy of stem cell interventions in the management of DF complications. A comprehensive systematic search across PubMed, Embase, CINAHL, Scopus, and the Cochrane library databases was conducted to identify pertinent studies for meta-analysis. Outcome measures encompassed ulcer or wound healing rates, amputation rates, angiogenesis, ankle-brachial index (ABI), and pain-free walking distance. Dichotomous outcomes were expressed as risk differences (RDs) with 95% confidence intervals (CIs), while continuous data were articulated as standardized mean differences (SMDs) with corresponding 95% CIs. Statistical analyses were executed using RevMan 5.3 and Open Meta, with bootstrapped meta-analysis conducted through OpenMEE software. A total of 20 studies, comprising 24 arms and involving 1304 participants, were incorporated into the meta-analysis. The findings revealed that stem cell therapy exhibited superior efficacy compared to conventional interventions in terms of ulcer or wound healing rate [RD = 0.36 (0.28, 0.43)], pain-free walking distance [SMD = 1.27 (0.89, 1.65)], ABI [SMD = 0.61 (0.33, 0.88)], and new vessel development [RD = 0.48 (0.23, 0.78)], while concurrently reducing the amputation rate significantly [RD = -0.19 (-0.25, -0.12)]. Furthermore, no statistically significant difference in adverse events was observed [RD -0.07 (-0.16, 0.02)]. The Grading of Recommendations, Assessment, Development, and Evaluation assessment indicated varying levels of evidence certainty, ranging from very low to moderate, for different outcomes. Bootstrapping analysis substantiated the precision of the results. The meta-analysis underscores the significant superiority of stem cell therapy over conventional approaches in treating DF complications. Future investigations should prioritize large-scale, randomized, double-blind, placebo-controlled, multicenter trials, incorporating rigorous long-term follow-up protocols. These studies are essential for elucidating the optimal cell types and therapeutic parameters that contribute to the most effective treatment strategies for DF management.

Stem Cell-Based Tissue Engineering Approaches for Diabetic Foot Ulcer: a Review from Mechanism to Clinical Trial

Diabetic foot ulcer (DFU) is a complication from incomplete or prolonged wound healing, at times requires amputation, putting substantial health and socioeconomic burden. Wound healing is a dynamic overlapping process that can be regulated by arrays of molecular factors showing redundancy in function. However, dysregulation in the mechanism of angiogenesis, extra cellular matrix (ECM) formation and immune modulation are the major causes for impair wound healing in hyperglycaemic patients. Despite development of wound care research, there is a lack of well-accepted targeted therapy with multidisciplinary approach for DFU treatment. Stem cell therapy holds a promising outcome both in preclinical and clinical trials because of its ability to promote healing via regeneration and specialized tissue differentiation. Among different types of stem cells, regenerative potential of mesenchymal stem cell (MSC) is well demonstrated in both experimental and clinical trial. Still there is a huge knowledge gap among medical practitioners for deciding the best stem cell source, administration route, and safety. This review strengthens the fact that why stem cell therapy is a promising candidate to treat DFU and cited multiple tissue engineering and biomaterial-based approaches for delivering stem cells and their aftermath paracrine events. Based on the pre-clinical and clinical studies, the review tried to come up with optimum stem cell source and delivery route for the treatment of DFU. At last, the review glances on possible direction to enhance therapeutics strategy for the same, including different approaches like: phytocompounds, exosomes, scaffold geometry, cell preconditioning and licensing etc.

Promotion of cutaneous diabetic wound healing by subcutaneous administration of Wharton's jelly mesenchymal stem cells derived from umbilical cord

Wound healing is a major problem in diabetic patients, and current treatments have been confronted with limited success. The present study examined the benefit of Wharton's jelly mesenchymal stem cells (WJ-MSCs) derived from the human umbilical cord (UC) in wound healing in diabetic rats. Thirty days after inducing diabetes, a circular excision was created in the skin of rats, and the treatments were performed for 21 days. Two groups were studied, which included the Control group and WJ-MSCs group. The studied groups were sampled on the 7th, 14th, and 21st days after wounding. Histological ultrasound imaging of dermis and epidermis in the wound area for thickness and density measurement and skin elasticity were evaluated. Our results on post-wounding days 7, 14, and 21 showed that the wound closure, thickness, and density of new epidermis and dermis, as well as skin elasticity in the healed wound, were significantly higher in the WJ-MSCs group compared to the Control group. Subcutaneous administration of WJ-MSCs in diabetic wounds can effectively accelerate healing. Based on this, these cells can be used along with other treatment methods in the healing of different types of chronic wounds.

LPS-pretreatment adipose-derived mesenchymal stromal cells promote wound healing in diabetic rats by improving angiogenesis

Mesenchymal stem cells (MSCs) play a key role in wound healing, and the advantages of pretreated MSCs in wound healing have previously been reported. In the present study, we investigated the impact of LPS pretreated human adipose-derived MSCs on skin wound healing in diabetic rats. We found that some improvements occurred through improving angiogenesis. Then, we scrutinized the impact of lipopolysaccharide (LPS) treatment on human adipose-derived MSCs in a high-glucose (HG) medium, as an in vitro diabetic model. In vivo findings revealed significant improvements in epithelialization and angiogenesis of diabetic wounds which received LPS pre-MSCs. Particularly, LPS pre-MSCs-treated diabetic wounds reached considerably higher percentages of wound closure. Also, the granulation tissue of these wounds had higher pronounced epithelialization and more vascularization compared with PBS-treated and MSCs-treated diabetic ones by CD31, VEGF, CD90, collagen 1, and collagen 3 immunostaining. Western-blots analyses indicated that LPS pre-MSCs led to the upregulation of vascular endothelial growth factor (VEGF) and DNMT1. In addition, significantly higher cell viability (proliferation/colonie), and elevated VEGF and DNMT1 protein expression were observed when MSCs were treated with LPS (10 ng/ml, 6 h) in HG culture media. Based on these findings, it is suggested that LPS pre-MSCs could promote wound repair and skin regeneration, in some major processes, via the improvement of cellular behaviors of MSCs in the diabetic microenvironment. The beneficial advantages of LPS treated with mesenchymal stem cells on wound healing may lead to establishing a novel approach as an alternative therapeutic procedure to cure chronic wounds in diabetic conditions.

Adipose-Derived Stem Cells for the Treatment of Diabetic Wound: From Basic Study to Clinical Application

Diabetic wounds significantly affect the life quality of patients and may cause amputation and mortality if poorly managed. Recently, a wide range of cell-based methods has emerged as novel therapeutic methods in treating diabetic wounds. Adipose-derived stem cells (ASCs) are considered to have the potential for widespread clinical application of diabetic wounds treatment in the future. This review summarized the mechanisms of ASCs to promote diabetic wound healing, including the promotion of immunomodulation, neovascularization, and fibro synthesis. We also review the current progress and limitations of clinical studies using ASCs to intervene in diabetic wound healing. New methods of ASC delivery have been raised in recent years to provide a standardized and convenient use of ASCs.

Constructing Tissue-Engineered Dressing Membranes with Adipose-Derived Stem Cells and Acellular Dermal Matrix for Diabetic Wound Healing: A Comparative Study of Hypoxia- or Normoxia-Culture Modes

Diabetes foot ulcer (DFU) is a serious complication of diabetes, characterized by impaired vascular function, limited angiogenesis, and chronic inflammation. Direct stem cell injection on treating DFU is far from satisfactory in clinical practice, as this therapy neither protects nor localizes the injected cell suspension at the chronic ulcer site. Meanwhile, most of injected cells gradually perished within several days due to senescence or apoptosis. Acellular dermal matrix (ADM) has the potential to act as excellent cell delivery vehicles, considering it is highly biomimetic to native dermal tissue, has low immunogenicity, and suitable for stem cell attachment and proliferation. Hypoxia culture has significantly enhanced effects on the survival ability of in vitro cultured stem cells, indicating this culture mode is a suitable way for inhibiting the senescence or apoptosis of transplanted cells. In the current study, we, respectively, culture adipose-derived stem cells (ADSCs) on an ADM membrane under a hypoxia or normoxia condition to construct two kinds of tissue-engineered dressing membranes (H-ADSCs/ADM and N-ADSCs/ADM) and then comparatively evaluated their efficacy on DFU healing using a diabetic rat model. In vitro results showed that hypoxia precondition could stimulate the ADSCs secreting VEGF-A, and the culture medium from hypoxia-preconditioned ADSCs could enhance the proliferation, migration, and angiogenesis of HUVECs. In vivo results indicated that compared to the N-ADSCs/ADM membrane, the transplanted cells in the H-ADSCs/ADM membrane can survive longer at the chronic ulcer site, consequently improve angiogenesis, inhibit inflammation, and increase extracellular matrix remodeling, eventually accelerating DFU closure. This study provides an innovative covering graft for the treatment of DFU in the clinic.

Regulatory Processes of the Canonical Wnt/β-Catenin Pathway and Photobiomodulation in Diabetic Wound Repair

Skin is a biological system composed of different types of cells within a firmly structured extracellular matrix and is exposed to various external and internal insults that can break its configuration. The restoration of skin's anatomic continuity and function following injury is a multifaceted, dynamic, well-coordinated process that is highly dependent on signalling pathways, including the canonical Wnt/β catenin pathway, all aimed at restoring the skin's protective barrier. Compromised and inappropriate tissue restoration processes are often the source of wound chronicity. Diabetic patients have a high risk of developing major impediments including wound contamination and limb amputation due to chronic, non-healing wounds. Photobiomodulation (PBM) involves the application of low-powered light at specific wavelengths to influence different biological activities that incite and quicken tissue restoration. PBM has been shown to modulate cellular behaviour through a variety of signal transduction pathways, including the Wnt/β catenin pathway; however, the role of Wnt/β catenin in chronic wound healing in response to PBM has not been fully defined. This review largely focuses on the role of key signalling pathways in human skin wound repair, specifically, the canonical Wnt/β-catenin pathway, and the effects of PBM on chronic wound healing.

c-Casitas b-Lineage Lymphoma Downregulation Improves the Ability of Long-term Cultured Mesenchymal Stem Cells for Promoting Angiogenesis and Diabetic Wound Healing

The chronic wound induced by diabetes has poor efficacy and could lead to amputation. The repair function of mesenchymal stem cells (MSCs) impaired after long-term culture in vitro. Studies have shown that the proto-oncogene c-Casitas b-lineage lymphoma (c-Cbl) can regulate receptor- and non-receptor tyrosine kinase, which was also involved in the angiogenesis process. This study aimed to explore the regulative effect of c-Cbl on the proangiogenic functions of long-term cultured MSCs and evaluate its pro-healing effect on diabetic wounds. In this study, the c-Cbl level was downregulated by locked nucleic acid–modified antisense oligonucleotide gapmers (LNA Gapmers). We detected the effect of c-Cbl downregulation on long-term cultured MSCs in terms of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signal, cellular proliferation, senescence, migration, and angiogenic factors paracrine activity in vitro. In vivo, we observed the pro-healing effect of long-term cultured MSCs, with or without c-Cbl downregulation, on the diabetic wound. We found that the phosphorylation level of c-Cbl increased and that of Akt decreased in passage 10 (P10) MSCs compared with passage 3 (P3) MSCs (P < 0.05). Additionally, the proliferation, paracrine, and migration capacity of P10 MSCs decreased significantly, accompanied by the increase of cellular senescence (P < 0.05). However, these functions, including PI3K/Akt activity of P10 MSCs, have been improved by c-Cbl downregulation (P < 0.05). Compared with P10 MSCs treatment, treatment with c-Cbl downregulated P10 MSCs accelerated diabetic wound healing, as defined by a more rapid wound closure (P < 0.05), more neovascularization (P < 0.05), and higher scores of wound histological assessment (P < 0.05) in a diabetic rat model. Our findings suggested that c-Cbl downregulation could attenuate the impairment of proangiogenic functions in MSCs induced by long-term culture in vitro and improve the effect of long-term cultured MSCs in promoting diabetic wound healing.

Cellular Senescence as the Pathogenic Hub of Diabetes-Related Wound Chronicity

Diabetes is constantly increasing at a rate that outpaces genetic variation and approaches to pandemic magnitude. Skin cells physiology and the cutaneous healing response are progressively undermined in diabetes which predisposes to lower limb ulceration, recidivism, and subsequent lower extremities amputation as a frightened complication. The molecular operators whereby diabetes reduces tissues resilience and hampers the repair mechanisms remain elusive. We have accrued the notion that diabetic environment embraces preconditioning factors that definitively propel premature cellular senescence, and that ulcer cells senescence impair the healing response. Hyperglycemia/oxidative stress/mitochondrial and DNA damage may act as major drivers sculpturing the senescent phenotype. We review here historical and recent evidences that substantiate the hypothesis that diabetic foot ulcers healing trajectory, is definitively impinged by a self-expanding and self-perpetuative senescent cells society that drives wound chronicity. This society may be fostered by a diabetic archetypal secretome that induces replicative senescence in dermal fibroblasts, endothelial cells, and keratinocytes. Mesenchymal stem cells are also susceptible to major diabetic senescence drivers, which accounts for the inability of these cells to appropriately assist in diabetics wound healing. Thus, the use of autologous stem cells has not translated in significant clinical outcomes. Novel and multifaceted therapeutic approaches are required to pharmacologically mitigate the diabetic cellular senescence operators and reduce the secondary multi-organs complications. The senescent cells society and its adjunctive secretome could be an ideal local target to manipulate diabetic ulcers and prevent wound chronification and acute recidivism. This futuristic goal demands harnessing the diabetic wound chronicity epigenomic signature.

Regulation of inflammatory microenvironment using a self-healing hydrogel loaded with BM-MSCs for advanced wound healing in rat diabetic foot ulcers

A diabetic foot ulcer (DFUs) is a state of prolonged chronic inflammation, which can result in amputation. Different from normal skin wounds, various commercially available dressings have not sufficiently improved the healing of DFUs. In this study, a novel self-healing hydrogel was prepared by in situ crosslinking of N-carboxyethyl chitosan (N-chitosan) and adipic acid dihydrazide (ADH) with hyaluronic acid-aldehyde (HA-ALD), to provide a moist and inflammatory relief environment to promote stem cell proliferation or secretion of growth factors, thus accelerating wound healing. The results demonstrated that this injectable and self-healing hydrogel has excellent swelling properties, stability, and mechanical properties. This biocompatible hydrogel stimulated secretion of growth factors from bone marrow mesenchymal stem cells (BM-MSCs) and regulated the inflammatory environment by inhibiting the expression of M1 macrophages and promoting the expression of M2 macrophages, resulting in granulation tissue formation, collagen deposition, nucleated cell proliferation, neovascularization, and enhanced diabetic wound healing. This study showed that N-chitosan/HA-ALD hydrogel could be used as a multifunctional injectable wound dressing to regulate chronic inflammation and provide an optimal environment for BM-MSCs to promote diabetic wound healing.

Autologous micro-fragmented adipose tissue for the treatment of diabetic foot minor amputations: a randomized controlled single-center clinical trial (MiFrAADiF)

Background

The diabetic foot ulcer (DFU) is one of the most prevalent complications of diabetes mellitus and often develops severe effects that can lead to amputation. A non-healing “minor” amputation often precedes a major amputation resulting in a negative impact on the function and quality of life of the patients. Stem cell-based therapies have emerged as a promising option to improve healing, and the adipose tissue is an abundant and easy to access source. The injection of autologous micro-fragmented adipose tissue at the amputation stump of a diabetic population undergoing a lower limb minor amputation was evaluated and compared with the standard care.

Methods

In this randomized controlled trial with two arms (parallel assignment) and no masking, 114 patients undergoing a lower limb minor amputation were randomized to standard of care or to micro-fragmented adipose tissue injection prepared using a minimal manipulation technique (Lipogems®) in a closed system. Clinical outcomes were determined monthly up to 6 months. Primary endpoint of the study was the evaluation of the healing rate and time after the minor amputation. Secondary endpoints included the assessment of safety, feasibility, technical success, relapse rate, skin tropism, and intensity of pain.

Results

At 6 months, 80% of the micro-fragmented adipose tissue-treated feet healed and 20% failed as compared with the control group where 46% healed and 54% failed (p = 0.0064). No treatment-related adverse events nor relapses were documented, and technical success was achieved in all cases. The skin tropism was improved in the treatment group, and the pain scale did not differ between the two groups.

Conclusion

The results of this randomized controlled trial suggest that the local injection of autologous micro-fragmented adipose tissue is a safe and valid therapeutic option able to improve healing rate following minor amputations of irreversible DFU. The technique overcomes several stem cell therapy-related criticisms and its potential in wound care should be better evaluated and the therapeutic indications could be expanded.

Trial registration

ClinicalTrials.gov number: NCT03276312. Date of registration: September 8, 2017 (retrospectively registered).

Use of Biologically Active 3D Matrix for Extensive Skin Defect Treatment in Veterinary Practice: Case Report

Objectives: Large full-thickness skin defects represent a serious veterinary problem. Methods: We have developed novel bioactive 3D-matrixes based on fibrin glue Tissucol (Baxter), containing the combination of the adenoviral constructs with genes vascular endothelial growth factor 165 (VEGF165) and fibroblast growth factor two (FGF2; construct Ad5-VEGF165 + Ad5-FGF2) or multipotent mesenchymal stem cells, genetically modified with these constructs. Results: In vitro studies confirmed the biosynthesis of VEGF165 and FGF2 mRNA in the transduced cells. Ad5-VEGF165 + Ad5-FGF2- transduced multipotent mesenchymal stem cells showed an enhanced capacity to form capillary-like tubes in vitro. Bioactive 3D-matrix application enhanced granulation tissue formation and epithelialization of non-healing, large bite wounds in a dog. Successful wound healing was observed with a positive clinical outcome for the canine patient. This research and application of regenerative gene therapy alongside a novel bioactive 3D-matrix shows promising clinical applications for the future in both dogs and other mammals including humans.

Netrin-1 improves adipose-derived stem cell proliferation, migration, and treatment effect in type 2 diabetic mice with sciatic denervation

BACKGROUND

Diabetic peripheral neurovascular diseases (DPNVs) are complex, lacking effective treatment. Autologous/allogeneic transplantation of adipose-derived stem cells (ADSCs) is a promising strategy for DPNVs. Nonetheless, the transplanted ADSCs demonstrate unsatisfying viability, migration, adhesion, and differentiation in vivo, which reduce the treatment efficiency. Netrin-1 secreted as an axon guidance molecule and served as an angiogenic factor, demonstrating its ability in enhancing cell proliferation, migration, adhesion, and neovascularization.

METHODS

ADSCs acquired from adipose tissue were modified by Netrin-1 gene (NTN-1) using the adenovirus method (N-ADSCs) and proliferation, migration, adhesion, and apoptosis examined under high-glucose condition. The sciatic denervated mice (db/db) with type 2 diabetes mellitus (T2DM) were transplanted with N-ADSCs and treatment efficiency assessed based on the laser Doppler perfusion index, immunofluorescence, and histopathological assay. Also, the molecular mechanisms underlying Netrin-1-mediated proliferation, migration, adhesion, differentiation, proangiogenic capacity, and apoptosis of ADSCs were explored.

RESULTS

N-ADSCs improved the proliferation, migration, and adhesion and inhibited the apoptosis of ADSCs in vitro in the condition of high glucose. The N-ADSCs group demonstrated an elevated laser Doppler perfusion index in the ADSCs and control groups. N-ADSCs analyzed by immunofluorescence and histopathological staining demonstrated the distribution of the cells in the injected limb muscles, indicating chronic ischemia; capillaries and endothelium were formed by differentiation of N-ADSCs. The N-ADSCs group showed a significantly high density of the microvessels than the ADSCs group. The upregulation of AKT/PI3K/eNOS/P-38/NF-κB signaling pathways and secretion of multiple growth factors might explain the positive effects of Netrin-1 on ADSCs.

CONCLUSION

The overexpression of Netrin-1 in ADSCs improves proliferation, migration, and treatment effect in type 2 diabetic mice with sciatic denervation, which directs the clinical treatment of patients with DPNVs.

Pathogenesis of wound healing disorders in the elderly

The elderly constitute the age group most susceptible to wound healing disorders and chronic wounds, the most prevalent being venous leg ulcers, pressure ulcers, and diabetic foot ulcers. However, other age-associated diseases should also be taken into consideration in the diagnostic workup of chronic wounds, and not be underestimated. A better understanding of the pathomechanisms involved in the wound healing process is of key importance in combatting the difficulties associated with the treatment of chronic wounds. In recent decades, considerable progress has been made in the development of pioneering therapeutic strategies for chronic wounds. In this context, the use of growth factors and cytokines, tissue engineering, and cell therapy - including stem cells - have proven very promising. Nevertheless, prior to their introduction into routine clinical practice, large controlled clinical trials are required to assess the safety of these techniques.

Diabetes mellitus and the skin

Diabetes is a debilitating, life-threatening disease accounting in 2015 for the death of 5 million people worldwide. According to new estimations, 415 million adults currently suffer from the disease, and this number is expected to rise to 642 million by 2040. High glucose blood levels also affect the skin among systemic organs, and skin disorders can often predict the onset of this metabolic disorder. In this review, we address the pathomechanistic effects of diabetes on the skin and give an overview on the most common skin diseases associated with diabetes.

Intermittent cycles of remote ischemic preconditioning augment diabetic foot ulcer healing

The morbidity and mortality caused by diabetic foot ulcer (DFU) are still significant. Conservative treatment of DFU is often ineffective. Treatment modalities using stem cells directly into the DFU or systematically have been introduced recently. Ischemic preconditioning (IPC) has been proved to be a cheap, simple, and safe method which can augment stem cells number in the peripheral blood circulation. This study's purpose was to test whether IPC can improve DFU healing. Forty diabetic patients were enrolled and divided into study and control groups. All patients received their regular treatment. The study group patients received in addition brief, transient cycles of IPC while the control group patients received a sham procedure only. The procedure was repeated every 2 weeks to complete a follow-up period of 6 weeks. The ulcers were photographed to measure wound area, and the degree of granulation tissue was assessed. No serious adverse events were noted. Twenty-two patients from the study group and 12 from the control group completed the entire follow-up. The ratio of patients who reached complete healing of their ulcer was 9/22 (41%) in the study group compared with 0/12 (0%) in the control group, p = 0.01. Furthermore, the mean remaining ulcer area at the end of the follow-up was significantly smaller in the study group, 25 ± 6% of the initial area vs. 61 ± 10% in the control group, p = 0.007. The degree of granulation increased after one cycle of treatment in 8/24 (33%) study patients compared to 3/16 (19%) in the control group, p = 0.47. Remote, repeated IPC significantly improves the healing of DFU. This simple, safe, inexpensive treatment method should be considered to be routinely applied to diabetic patients with DFU in addition to other regular treatment modalities.

Effectiveness of Autologous Stem Cell Therapy for the Treatment of Lower Extremity Ulcers: A Systematic Review and Meta-Analysis

Primary studies in animal models and humans have suggested the therapeutic potential of autologous stem cell for treating chronic lower extremity ulcers. However, the results of pilot randomized controlled trials (RCTs) in humans have been inconsistent. A meta-analysis of RCTs was performed to evaluate the role of autologous stem cell-based therapy for lower extremity ulcers.Studies were identified during a systematic search of Medline, Embase, Cochrane's library, and references cited in related reviews and studies. Studies were included if they were RCTs published in English, recruited patients with lower extremity ulcers who were assigned to either a group for the topical therapy with autologous stem cells, and reported data regarding the healing of the ulcers.Relative risks (RRs) for healing rate and standardized mean differences (SMDs) for the changes in the mean sizes of ulcers were evaluated with a random-effects model. Overall, autologous stem cell-based therapy was associated with better healing of lower extremity ulcers (12 comparisons, 290 patients, RR for partial healing = 3.07, 95% confidence interval [CI] = 1.14-8.24, P = 0.03; RR for complete healing = 2.26, 95% CI = 1.48-3.16, P < 0.001) with little heterogeneity (I = 0%). Moreover, autologous stem cell-based therapy was associated with a greater reduction in mean ulcer size (SMD = -0.63, 95% CI = -1.03 to -0.22, P = 0.002). Subgroup analyses indicated that stem cells from peripheral blood and bone marrow seemed to exert similar beneficial effects on the healing of ulcers. Stem cell therapy was not associated with any increased risks for adverse events. The optimized sources, amounts, and delivery methods of stem cell -based therapy for patients with chronic lower extremity ulcers need to be determined, and the long-term effects of stem cell-based therapy on clinical outcomes need further exploration.Autologous stem cell-based therapy is effective and safe for improving the healing of chronic lower extremity ulcers and large-scale RCTs are needed to confirm our findings.

In Vitro Evaluation of Scaffolds for the Delivery of Mesenchymal Stem Cells to Wounds

Mesenchymal stem cells (MSCs) have been shown to improve tissue regeneration in several preclinical and clinical trials. These cells have been used in combination with three-dimensional scaffolds as a promising approach in the field of regenerative medicine. We compare the behavior of human adipose-derived MSCs (AdMSCs) on four different biomaterials that are awaiting or have already received FDA approval to determine a suitable regenerative scaffold for delivering these cells to dermal wounds and increasing healing potential. AdMSCs were isolated, characterized, and seeded onto scaffolds based on chitosan, fibrin, bovine collagen, and decellularized porcine dermis. In vitro results demonstrated that the scaffolds strongly influence key parameters, such as seeding efficiency, cellular distribution, attachment, survival, metabolic activity, and paracrine release. Chick chorioallantoic membrane assays revealed that the scaffold composition similarly influences the angiogenic potential of AdMSCs in vivo. The wound healing potential of scaffolds increases by means of a synergistic relationship between AdMSCs and biomaterial resulting in the release of proangiogenic and cytokine factors, which is currently lacking when a scaffold alone is utilized. Furthermore, the methods used herein can be utilized to test other scaffold materials to increase their wound healing potential with AdMSCs.

VEGF gene transfected umbilical cord mesenchymal stem cells transplantation improve the lower limb vascular lesions of diabetic rats

BACKGROUND

Previous studies had explored the therapeutic effect of hUC-MSCs transplantation on ischemia; in this study, we further assessed the effectiveness of VEGF over-expressed hUC-MSCs cells transplantation on vascular proliferation in lower limb ischemia model in type 2 diabetic rats.

METHODS

hUC-MSCs cells were over-expressed with VEGF, and transplanted to lower limb ischemia rats model of type 2 diabetes.

RESULTS

VEGF over-expression increased the hUC-MSCs cells proliferation activity and VEGF secretion. VEGF gene transfected hUC-MSCs transplantation increased VEGF expression at a high level throughout 4weeks in skeletal muscle tissues of rats. Importantly, the vascular proliferation and blood perfusion of VEGF over-expressed hUC-MSCs transplanted limb were significantly improved compared with those of control group. The expression levels of ERK, AKT, MMP2 and MMP9 in VEGF over-expressed hUC-MSCs transplantation group increased dramatically compared with control group, while TIMP1 and TIMP2 expression had no significant change.

CONCLUSION

VEGF over-expressed hUC-MSCs transplantation was more effective to stimulate angiogenesis and increase blood perfusion than the simply hUC-MSCs transplantation, as maybe a new choice to improve the lower limb vascular lesions of diabetics.

Optimizing isolation culture and freezing methods to preserve Wharton's jelly's mesenchymal stem cell (MSC) properties: an MSC banking protocol validation for the Hellenic Cord Blood Bank

BACKGROUND

Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from many tissues including umbilical cord Wharton's jelly (UC-WJ). Although initially limited in studies such as a hematopoietic stem cell transplantation adjuvant, an increasing number of clinical trials consider MSCs as a potential anti-inflammatory or a regenerative medicine agent. It has been proposed that creating a repository of MSCs would increase their availability for clinical applications. The aim of this study was to assess the optimal isolation and cryopreservation procedures to facilitate WJ MSC banking.

STUDY DESIGN AND METHODS

Cells were isolated from UC-WJ using enzymatic digestion or plastic adhesion methods. Their isolation efficacy, growth kinetics, immunophenotype, and differentiation potential were studied, as well as the effects of freezing. Flow cytometry for common MSC markers was performed on all cases and differentiation was shown with histocytochemical staining. Finally, the isolation efficacy on cryopreserved WJ tissue fragments was tested.

RESULTS

MSC isolation was successful using both isolation methods on fresh UC-WJ tissue. However, UC-WJ MSC isolation from frozen tissue fragments was impossible. Flow cytometry analysis revealed that only MSC markers were expressed on the surface of the isolated cells while differentiation assays showed that they were capable of trilinear differentiation. All the above characteristics were also preserved in isolated UC-WJ MSCs over the cryopreservation study period.

CONCLUSION

These data showed that viable MSCs can only be isolated from fresh UC-WJ tissue, setting the foundation for clinical-grade banking.