Stromal vascular fraction cells for the treatment of critical limb ischemia: a pilot study

The Combination of Stromal Vascular Fraction Cells and Platelet-Rich Plasma Mediates the Inflammatory Process in Deep Dermal Burn Injury

The combination of platelet-rich plasma (PRP) and stromal vascular fraction cells (SVFs) was beneficial in accelerating wound healing. This study aims to assess the effect of this combination in balancing the inflammatory process to accelerate burn healing. Thirty eligible Wistar rats were used in this study to establish a deep dermal degree burn wound model. They were randomly divided into four groups: locally injected with the combination of SVFs and PRP (n=9), vaseline (n=9), placebo (n=9), and healthy Wistar rats group (n=3), as treatment group, positive control group, negative control group and healthy control group, respectively. The burn wound tissue was excised from three separated sacrificed rats (8, 24 and 48 hours) to examine polymorphonuclear (PMN) and lymphocyte counts through the standard hematoxylin-eosin procedure and for cyclooxygenase2 (COX-2) expression through the immunohistochemical procedure. The highest PMN, lymphocyte cell count, and COX 2 expression were found at 8 hours in the local injection with the PRP combination SVF group (28,555±11,237, 8,111±3,218, and 4,666±2,309, respectively, p <0.05 except for COX 2). The regression analysis results showed that local injection of a combination of PRP and SVF could reduce PMN cells by 1.068 times, lymphocytes by 1.786 times, and COX 2 by 1.853 times greater than topical application with vaseline. The combined injection of PRP and SVF effectively heals deep burns by acutely increasing the PMN cell and lymphocyte count, and COX 2 expression. Conversely, the treatment decreased the PMN cell and lymphocyte count but not the COX 2 expression in the sub-acute phase of wound healing.

Autologous cell therapy in diabetes‑associated critical limb ischemia: From basic studies to clinical outcomes (Review)

Cell therapy is becoming an attractive alternative for the treatment of patients with no‑option critical limb ischemia (CLI). The main benefits of cell therapy are the induction of therapeutic angiogenesis and neovascularization that lead to an increase in blood flow in the ischemic limb and tissue regeneration in non‑healing cutaneous trophic lesions. In the present review, the current state of the art of strategies in the cell therapy field are summarized, focusing on intra‑operative autologous cell concentrates in diabetic patients with CLI, examining different sources of cell concentrates and their mechanisms of action. The present study underlined the detrimental effects of the diabetic condition on different sources of autologous cells used in cell therapy, and also in delaying wound healing capacity. Moreover, relevant clinical trials and critical issues arising from cell therapy trials are discussed. Finally, the new concept of cell therapy as an adjuvant therapy to increase wound healing in revascularized diabetic patients is introduced.

Combination of platelet rich plasma and stromal vascular fraction on the level of vascular endothelial growth factor in rat subjects experiencing deep dermal burn injury

Background

The healing process of burns includes coagulation, inflammation, and remodeling. Vascular endothelial growth factor (VEGF) is involved throughout this healing process. Stem cells from the platelet-rich plasma (PRP) with stromal vascular fraction (SVF) can increase concentrations of growth factors, including VEGF. This is expected to accelerate burn healing. The aim of this study was to determine the effect of a combination of PRP and SVF on VEGF levels in a rats model of deep dermal burn wound healing.

Materials and methods

This is an experimental research study in rats using a post-test control group design with 4 groups: A) control, B) Vaseline, C) topical PRP and SVF, and D) PRP and SVF injection. Burn wounds were induced according to the modified Guo method.

Results

In a rats model of deep dermal wound healing, topical Vaseline significantly increased serum VEGF compared to control. Topical application and injection of stem cells also significantly increased serum VEGF compared to control and Vaseline. The VEGF concentration was significantly higher following injection of PRP and SVF, suggesting that the injection route is more effective at increasing VEGF levels compared to the topical application of stem cells.

Conclusion

The combination of PRP and SVF, either by injection or topical application, can increase VEGF levels during the healing process from deep dermal burns.

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Stem cells can increase concentrations of growth factors.

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Topical application and injection of stem cells significantly increased serum VEGF compared to control.

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The VEGF concentration was significantly higher following injection of PRP and SVFs.

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The injection route of stem cells is more effective at increasing VEGF levels compared to the topical application.

The efficacy and safety of autologous stromal vascular fraction transplantation for infraorbital skin rejuvenation: A clinical prospective study

BACKGROUND

The stromal vascular fraction of fat tissue contributes to its rejuvenation properties. The stromal vascular fraction is a minimal processed cell population. Therefore, it is purportedly a suitable cell therapy for skin rejuvenation.

OBJECTIVES

This clinical trial aimed to evaluate the efficacy and safety of transplantation of autologous stromal vascular fraction to aging skin in the infraorbital region.

PATIENTS/METHODS

Nineteen patients were candidates for stromal vascular fraction isolation and transplantation. They underwent lipoaspiration of the abdomen to obtain samples of fat tissue. The stromal vascular fraction was thereafter harvested and transplanted in each infraorbital area. The patients' outcomes were measured and were based on surface evaluation of wrinkles, surface evaluation of scaliness, and melanin evaluation with a Mexameter. The red blood cell volume and skin elasticity were measured with an erythrometer and cutometer, respectively.

RESULTS

Three months and 6 months after autologous stromal vascular fraction transplantation, the elasticity, wrinkle, and pigmentation of the infraorbital skin improved significantly, but not surface evaluation of scaliness and erythema. The phenotype also improved in the infraorbital skin area, as evaluated by physicians.

CONCLUSION

The stromal vascular fraction of adipose tissue represents an attractive cell source. In our study, preliminary data showed that clinical outcomes were also generally satisfactory with no serious adverse effects. Thus, stromal vascular fraction cells are safe for clinical rejuvenation use. We encourage future evidence-based controlled studies to maintain a strong focus on the efficacy and safety profile of stromal vascular fraction therapy.

A Retrospective Study of Stromal Vascular Fraction Cell Therapy for Osteoarthritis

Background

Osteoarthritis (OA) is progressive degenerative damage to articular cartilage. Current therapeutic options are reduced to control the OA-associated symptoms, leaving the degenerative changes to progress until a joint replacement becomes mandatory. Therefore, therapeutic alternatives are warranted to improve the patient’s quality of life. Cell-based therapy is a developing therapeutic modality, showing promising results in the regeneration of injured cartilage and reduction of on-going inflammation within the affected joint. The current retrospective chart review study was aimed to analyze changes in pain and mobility of subjects with OA after stromal vascular fraction (SVF) cell therapy.

Methods

Three hundred fifty subjects with hip and knee OA, treated with autologous SVF cells at the Malacky Hospital (Bratislava, Slovakia) in the period from 2015 to 2018, were included in the retrospective chart review study.

Results

Seven days after SVF cell therapy, 45.2% of subjects experienced improved pain levels and mobility. Three, 6, and 12 months after therapy, improvement in pain levels reached 75.3%, 84.4%, and 84.9%, and improvement in mobility reached 75.2%, 84.4%, and 84.9%.

Conclusions

Our study of 350 subjects with hip and knee OA showed a significant improvement in pain levels and mobility 3, 6, and 12 months compared to 7 days after autologous SVF cell administration. The treatment demonstrated a strong safety profile with no severe adverse events or complications reported. The results of the study are showing that SVF cell therapy was more effective in subjects with arthritis stage III compared to arthritis stages I, II, and IV.

3D co-culture model of endothelial colony-forming cells (ECFCs) reverses late passage adipose-derived stem cell senescence for wound healing

Background

Extensive passage of adipose-derived stem cells (ASCs) in vitro leads to loss of function. Endothelial colony-forming cells (ECFCs) can be isolated from adult peripheral blood. A 3D co-culture system may rescue in vitro ASC senescence.

Methods

A 3D co-culture model was successfully established using hyaluronic acid (HA) gel and a 10:1 ratio of late-passage ASCs and ECFCs. Cell density and culture conditions were optimized. Stem cell phenotype was characterized by flow cytometry. ELISA was used to measure the trophic effect of angiogenic growth factors and compare the effects of these factors between the 3-D co-culture and single-cell culture. Therapeutic potential of ASC/ECFC 3-D co-cultures was evaluated in a mouse chronic injury model.

Results

Following incubation in a HA substrate 3D co-culture system, ASC morphology, phenotype, secretory profile, and differentiation capacity were restored. The ASC/ECFC co-culture increased the secretion of cytokines, such as hepatocyte growth factor, compared with single-cell 3D culture or monolayer culture. Mice radiation-ulcer wounds treated with ASC/ECFC 3-D co-cultures (spheroids) showed epithelialization and improved healing compared with wounds treated with ASCs or ECFCs alone. Further, transplanted ASC/ECFC spheroids exhibited superior angiogenic potential due to the ability of the ASCs to transdifferentiate into pericytes.

Conclusion

3D co-culture of ECFCs and ASCs in vitro restored native ASC properties by reversing cellular senescence and loss of trophic function. Transplant of ASC/ECFC 3D spheroids in vivo demonstrated pro-angiogenic capacity with improved therapeutic potential.

Adipose-derived stem cells promote diabetic wound healing via the recruitment and differentiation of endothelial progenitor cells into endothelial cells mediated by the VEGF-PLCγ-ERK pathway

Adipose-derived stem cell (ADSC) therapy is a promising treatment strategy for wound healing; however, the mechanism underlying this effect remains unclear. In the present study, we aimed to explore the influence of ADSC-derived VEGF on diabetic wounds and its role in modulating endothelial progenitor cells. The effect of ADSCs and ADSC-derived VEGF in vivo was investigated using a diabetic wound healing model, and inflammatory factors, such as IL-6, IL-10, and TNF-α, were detected. RT-qPCR and western blot analysis were used to detect the expression of downstream targets. In addition, the role of ADSC-derived VEGF in modulating endothelial progenitor cells (EPCs) was investigated using EdU assay, CD-31 immunofluorescence, and Transwell assay in vitro. The results show that ADSCs accelerated diabetic wound tissue closure and decreased the expression of inflammatory factors, such as IL-6, IL-10, and TNF-α. Further molecular mechanism studies indicated that coculturing EPCs with ADSC--conditioned medium enhanced the proliferation, mobilization and differentiation of EPCs into endothelial cells. This enhancement was inhibited when the expression of the VEGF downstream signal molecules VEGFR2, PLCγ, and ERK1/ERK2 was blocked, indicating that ADSCs might accelerate diabetic wound healing through the recruitment and differentiation of EPCs mediated by VEGF. Overall, the results of the study revealed that ADSCs could promote diabetic wound healing through the recruitment and differentiation of EPCs via angiogenesis effects regulated by the VEGF-PLCγ-ERK1/ERK2 pathway and suppression of the inflammatory response. In addition, it will be helpful to establish further understanding of ADSC therapy for clinical application.

Role of stem cell therapies in treating chronic wounds: A systematic review

BACKGROUND

The impairment of cutaneous wound healing results in chronic, non-healing wounds that are caused by altered wound environment oxygenation, tissue injury, and permissive microbial growth. Current modalities for the treatment of these wounds inadequately address the complex changes involved in chronic wound pathogenesis. Consequently, stem cell therapies have emerged as a potential therapeutic modality to promote cutaneous regeneration through trophic and paracrine activity.

AIM

To investigate current literature regarding use of stem cell therapies for the clinical treatment of chronic, non-healing wounds.

METHODS

PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus were queried with combinations of the search terms “mesenchymal stem cells,” “adult stem cells,” “embryonic stem cells,” “erythroid precursor cells,” “stem cell therapies,” and “chronic wounds” in order to find relevant articles published between the years of 2000 and 2019 to review a 20-year experience. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (reviews, case reports/series, retrospective/prospective studies, and clinical trials) were evaluated by the authors for their depiction of clinical stem cell therapy use. Data were extracted from the articles using a standardized collection tool.

RESULTS

A total of 43 articles describing the use of stem cell therapies for the treatment of chronic wounds were included in this review. While stem cell therapies have been explored in in vitro and in vivo applications in the past, recent efforts are geared towards assessing their clinical role. A review of the literature revealed that adipose-derived stem cells, bone marrow-derived stem cells, bone marrow-derived mononuclear cells, epidermally-derived mesenchymal stem cells, fibroblast stem cells, keratinocyte stem cells, placental mesenchymal stem cells, and umbilical cord mesenchymal stem cells have all been employed in the treatment of chronic wounds of various etiologies. Most recently, embryonic stem cells have emerged as a novel stem cell therapy with the capacity for multifaceted germ cell layer differentiation. With the capacity for self-renewal and differentiation, stem cells can enrich existing cell populations in chronic wounds in order to overcome barriers impeding the progression of wound healing. Further, stem cell therapies can be utilized to augment cell engraftment, signaling and activity, and resultant patient outcomes.

CONCLUSION

Assessing observed clinical outcomes, potential for stem cell use, and relevant therapeutic challenges allows wound care stakeholders to make informed decisions regarding optimal treatment approaches for their patients’ chronic wounds.

Adipose-Derived Stem Cells for Regenerative Wound Healing Applications: Understanding the Clinical and Regulatory Environment

There is growing interest in the regenerative potential of adipose-derived stem cells (ADSCs) for wound healing applications. ADSCs have been shown to promote revascularization, activate local stem cell niches, reduce oxidative stress, and modulate immune responses. Combined with the fact that they can be harvested in large numbers with minimal donor site morbidity, ADSC products represent promising regenerative cell therapies. This article provides a detailed description of the defining characteristics and therapeutic potential of ADSCs, with a focus on understanding how ADSCs promote tissue regeneration and repair. It summarizes the current regulatory environment governing the use of ADSC products across Europe and the United States and examines how various adipose-derived products conform to the current UK legislative framework. Advice is given to clinicians and researchers on how novel ADSC therapeutics may be developed in accordance with regulatory guidelines.

Safety of Human Adipose Stromal Vascular Fraction Cells Isolated with a Closed System Device in an Immunocompetent Murine Pressure Ulcer Model

Pressure ulcers (PUs) result in part due to ischemia-reperfusion injury to the skin and present frequently in elderly or quadriplegic patients with reduced mobility. Despite the high economic and societal cost of this condition, PU therapy relies primarily on preventive strategies and invasive surgical intervention. A growing body of clinical literature suggests that localized injection of adipose-derived cells can accelerate and enhance the closure of PUs. The current study systematically evaluated the safety of human adipose stromal vascular fraction (SVF) cells isolated using a closed system device when injected into a murine PU injury model. The human SVF cells were characterized by colony-forming unit-fibroblast and differentiation assays before use. Young (2 months) immunocompetent C57BL/6 mice subjected to a magnet-induced ischemia-reperfusion injury were injected subcutaneously with human SVF cells at increasing doses (0.25-2 million cells). The size of the PU was monitored over a 20-day period. Both female and male mice tolerated the concentration-dependent injection of the SVF cells without complications. While male mice trended toward more rapid wound closure rates in response to lower SVF cell concentrations (0.25-0.5 million cells), female mice responded favorably to higher SVF cell concentrations (1-2 million cells); however, outcomes did not reach statistical significance in either sex. Overall, the study demonstrates that human SVF cells prepared with a closed system device designed for use at point of care can be safely administered for PU therapy in an immunocompetent host animal model.

Retraction Note to: Stromal vascular fraction cells for the treatment of critical limb ischemia: a pilot study

The Editor-in-Chief and the publisher have retracted this article [1]. An investigation by the Lithuanian Bioethics Committee concluded that, contrary to the statements in the article, the study described was not conducted in the Vilnius City Clinical Hospital and the Commission of Medical Ethics did not issue any approval for such a study.

Autotransplantation of the Adipose Tissue-Derived Mesenchymal Stromal Cells in Therapy of Venous Stasis Ulcers

Adipose tissue is a reliable source of mesenchymal stromal cells (MSC) for use in regenerative medicine. The aim of this pilot study was to describe the method, and assess the safety and the potential efficacy of transplantation of autologous adipose tissue-derived MSC for the treatment of chronic venous stasis ulcers. Study group consisted of 11 patients (mean age: 66.6 ± 9.5 years) with chronic venous stasis ulcers. Adipose tissue was harvested by tumescent-aspiration method. Stromal cells were separated using a dedicated closed system in a real-time bedside manner. The phenotype of cells was determined immediately after separation. Cell concentrate was implanted subcutaneously around the wound and the wound bed. All ulcers were assessed planimetrically before autotransplantation and every two weeks during the six-month follow-up. During the study all patients received standard local and general treatment. The preparation contained an average of 5.6 × 10⁶ ± 4 × 10⁶ cells per milliliter. The phenotype of 65-82% of transplanted cells expressed MSC markers: CD73⁺ CD90⁺ and CD34⁺. An improvement was observed in 75% of ulcers. The data showed highly significant negative correlation (p < 0.0001) between wound size and wound closure degree. There was no correlation of ulcer healing with other parameters evaluated, including age of the patients. No serious side effects were observed. Autotransplantation of adipose tissue stromal cells may be a safe and promising treatment method for chronic venous ulcers.

Safety and Efficacy of Human Adipose-Derived Stromal/Stem Cell Therapy in an Immunocompetent Murine Pressure Ulcer Model

Pressure injuries/ulcers are frequent complications in elderly, paraplegic, and quadriplegic patients, which account for considerable cost to the international health care economy and remain refractory to current treatment options. Autologous or allogeneic adult stromal/stem cells represent an alternative therapeutic approach. The current study extends prior findings by exploring the safety and efficacy of human adipose-derived stromal/stem cell (ASC) therapy in an established immunocompetent murine skin pressure ulcer model where dermal fibroblast cells (DFCs) served as a control. Human adipose tissue was processed using a closed system device designed for point-of-care use in the operating room and on file with the Food and Drug Administration. Cell characterization was performed using colony-forming unit-fibroblast, differentiation, and immunophenotypic assays in vitro. Wound healing was assessed over a 20-day period based on photomicrographs, histology, and immunohistochemistry. The isolated human ASCs displayed significantly greater colony formation relative to DFCs while both populations exhibited comparable immunophenotype and differentiation potential. Both fresh and cryopreserved human ASCs significantly accelerated and enhanced wound healing in young (2 month) mice of both sexes relative to DFC controls based on tissue architecture and CD68⁺ cell infiltration. In contrast, while injection of either fresh or cryopreserved human ASCs was safe in older mice, the fresh ASCs significantly enhanced wound closure relative to the cryopreserved ASCs. Overall, these findings support the safety and efficacy of human ASCs isolated using a closed system device designed for clinical procedures in the future treatment of pressure injuries.

Stromal vascular fraction technologies and clinical applications

Introduction: The heterogeneous pool of cells found in the stromal vascular fraction of adipose tissue (SVF) and the purified mesenchymal stromal/stem cells (ASCs) isolated from this pool have increasingly been used as therapeutic tools in regenerative medicine.Areas covered: As SVF and ASCs are different, and should be used in different manners according to various clinical and biological indications, we reviewed the current literature, and focused on the clinical use of SVF to appraise the main medical fields for development. Both enzymatic digestion and mechanical disruption have been used to obtain SVF for non-homologous use. The safety and/or benefits of SVF have been examined in 71 clinical studies in various contexts, mainly musculoskeletal conditions, wound healing, urogenital, and cardiovascular and respiratory diseases. The use of SVF as a therapy remains experimental, with few clinical trials.Expert opinion: SVF provides a cellular and molecular microenvironment for regulation of ASC' activities under different clinical conditions. SVF may enhance angiogenesis and neovascularization in wound healing, urogenital and cardiovascular diseases. In joint conditions, therapeutic benefits may rely on paracrine immune-modulatory and anti-inflammatory mechanisms. Novel point of care methods are emerging to refine SVF in ways that meet the regulatory requirements for minimal manipulation.

In vitro Engineering of a Skin Substitute Based on Adipose-Derived Stem Cells

In the field of wound healing, stem cell-based strategies are gaining importance for their regenerative potential. Adipose-derived stem cells (ADSCs) are a particular subset of mesenchymal stem cells present in the stromal-vascular fraction of the adipose tissue, today considered very attractive for their relative abundance and accessibility in the human body. However, ADSCs are still not routinely used in normal clinical practice. Several studies have also reported ADSC transplantation in association with biomaterials in an attempt to enhance the local retention and growth rate of the cells. The aim of our study was to evaluate the ability of ADSCs to build a dermal scaffold to be potentially used as a dermal substitute in the field of wound healing, with optimal biocompatibility and mechanical properties. ADSCs were defined as CD90-, CD73-, and CD105-positive cells. ADSCs turned out to be capable of secreting all the main components of the extracellular matrix (ECM) upon stimulation, thus efficiently producing a collagen and fibronectin-containing dermal matrix. We also checked whether the ADSC-produced dermal scaffold could be seeded with keratinocytes. The scaffolding material directly produced by ADSCs has several advantages when compared to the commercially available ones: it is easily obtained from the patients and it is 100% biocompatible and supports cell-ECM interaction. Moreover, it represents a possible powerful therapeutic tool for patients with chronic ulcers since it appears to be potentially grafted with keratinocytes layers, thus bypassing the classical two-step grafting procedure.

Extracorporeal shock wave-assisted adipose-derived fresh stromal vascular fraction restores the blood flow of critical limb ischemia in rat

We tested the hypothesis that extracorporeal-shock-wave (ECSW)-assisted adipose-derived stromal vascular fraction (SVF) therapy was better than either one for restoring the blood flow in critical limb ischemia (CLI). Adult male-SD rats were categorized into group 1 (sham-operated-control), group 2 (CLI), group 3 [CLI + ECSW (280 impulses/0.10 mJ/mm²) applied to left inguinal area at 3 h after CLI], group 4 [CLI + SVF (1.2 × 10⁶) implanted into CLI area at 3 h after CLI], group 5 (CLI + ECSW-SVF). In vitro studies showed that ECSW significantly enhanced angiogenesis in human umbilical-vein endothelial cells and carotid-artery ring, and SVF significantly suppressed inflammation (TNF-α/NF-Κb/IL-1ß/MMP-9) in smooth-muscle cells treated by LPS (all p < .001). By day 14 after CLI, the ratio of ischemic/normal blood flow (INBF) was highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but no difference was shown between the latter two groups (all p < .001). The fibrotic area in CLI region exhibited an opposite pattern of INBF ratio (all p < .0001). Protein (CD31/vWF/eNOS) and cellular (CD31/vWF) expressions and number of small vessels in CLI area exhibited an identical pattern, whilst protein expressions of apoptotic (caspase3/PARP/mitochondrial-Bax) fibrotic/DNA-damaged (Samd3/TFG-ß/γ-H2AX) biomarkers exhibited an opposite pattern to INBF among five groups (all p < .0001). The numbers of angiogenetic cells in CLI region (SDF-1α/VEGF/CXCR4) and endothelial-progenitor cells (C-kit/CD31+//Sca-1/CD31+//CD34/KDR+/VE-cadherin/CD34+) in circulation significantly and progressively increased from groups 2 to 5 (all p < .0001). In conclusion, ECSW-SVF therapy effectively enhanced angiogenesis and restoration of blood flow in CLI area.

Augmentation of Dermal Wound Healing by Adipose Tissue-Derived Stromal Cells (ASC)

The skin is the largest organ of the human body and is the first line of defense against physical and biological damage. Thus, the skin is equipped to self-repair and regenerates after trauma. Skin regeneration after damage comprises a tightly spatial-temporally regulated process of wound healing that involves virtually all cell types in the skin. Wound healing features five partially overlapping stages: homeostasis, inflammation, proliferation, re-epithelization, and finally resolution or fibrosis. Dysreguled wound healing may resolve in dermal scarring. Adipose tissue is long known for its suppressive influence on dermal scarring. Cultured adipose tissue-derived stromal cells (ASCs) secrete a plethora of regenerative growth factors and immune mediators that influence processes during wound healing e.g., angiogenesis, modulation of inflammation and extracellular matrix remodeling. In clinical practice, ASCs are usually administered as part of fractionated adipose tissue i.e., as part of enzymatically isolated SVF (cellular SVF), mechanically isolated SVF (tissue SVF), or as lipograft. Enzymatic isolation of SVF obtained adipose tissue results in suspension of adipocyte-free cells (cSVF) that lack intact intercellular adhesions or connections to extracellular matrix (ECM). Mechanical isolation of SVF from adipose tissue destructs the parenchyma (adipocytes), which results in a tissue SVF (tSVF) with intact connections between cells, as well as matrix. To date, due to a lack of well-designed prospective randomized clinical trials, neither cSVF, tSVF, whole adipose tissue, or cultured ASCs can be indicated as the preferred preparation procedure prior to therapeutic administration. In this review, we present and discuss current literature regarding the different administration options to apply ASCs (i.e., cultured ASCs, cSVF, tSVF, and lipografting) to augment dermal wound healing, as well as the available indications for clinical efficacy.

Autologous cells derived from different sources and administered using different regimens for 'no-option' critical lower limb ischaemia patients

BACKGROUND

Revascularisation is the gold standard therapy for patients with critical limb ischaemia (CLI). In over 30% of patients who are not suitable for or have failed previous revascularisation therapy (the 'no-option' CLI patients), limb amputation is eventually unavoidable. Preliminary studies have reported encouraging outcomes with autologous cell-based therapy for the treatment of CLI in these 'no-option' patients. However, studies comparing the angiogenic potency and clinical effects of autologous cells derived from different sources have yielded limited data. Data regarding cell doses and routes of administration are also limited.

OBJECTIVES

To compare the efficacy and safety of autologous cells derived from different sources, prepared using different protocols, administered at different doses, and delivered via different routes for the treatment of 'no-option' CLI patients.

SEARCH METHODS

The Cochrane Vascular Information Specialist (CIS) searched the Cochrane Vascular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Allied and Complementary Medicine Database (AMED), and trials registries (16 May 2018). Review authors searched PubMed until February 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving 'no-option' CLI patients comparing a particular source or regimen of autologous cell-based therapy against another source or regimen of autologous cell-based therapy.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the eligibility and methodological quality of the trials. We extracted outcome data from each trial and pooled them for meta-analysis. We calculated effect estimates using a risk ratio (RR) with 95% confidence interval (CI), or a mean difference (MD) with 95% CI.

MAIN RESULTS

We included seven RCTs with a total of 359 participants. These studies compared bone marrow-mononuclear cells (BM-MNCs) versus mobilised peripheral blood stem cells (mPBSCs), BM-MNCs versus bone marrow-mesenchymal stem cells (BM-MSCs), high cell dose versus low cell dose, and intramuscular (IM) versus intra-arterial (IA) routes of cell implantation. We identified no other comparisons in these studies. We considered most studies to be at low risk of bias in random sequence generation, incomplete outcome data, and selective outcome reporting; at high risk of bias in blinding of patients and personnel; and at unclear risk of bias in allocation concealment and blinding of outcome assessors. The quality of evidence was most often low to very low, with risk of bias, imprecision, and indirectness of outcomes the major downgrading factors.Three RCTs (100 participants) reported a total of nine deaths during the study follow-up period. These studies did not report deaths according to treatment group.Results show no clear difference in amputation rates between IM and IA routes (RR 0.80, 95% CI 0.54 to 1.18; three RCTs, 95 participants; low-quality evidence). Single-study data show no clear difference in amputation rates between BM-MNC- and mPBSC-treated groups (RR 1.54, 95% CI 0.45 to 5.24; 150 participants; low-quality evidence) and between high and low cell dose (RR 3.21, 95% CI 0.87 to 11.90; 16 participants; very low-quality evidence). The study comparing BM-MNCs versus BM-MSCs reported no amputations.Single-study data with low-quality evidence show similar numbers of participants with healing ulcers between BM-MNCs and mPBSCs (RR 0.89, 95% CI 0.44 to 1.83; 49 participants) and between IM and IA routes (RR 1.13, 95% CI 0.73 to 1.76; 41 participants). In contrast, more participants appeared to have healing ulcers in the BM-MSC group than in the BM-MNC group (RR 2.00, 95% CI 1.02 to 3.92; one RCT, 22 participants; moderate-quality evidence). Researchers comparing high versus low cell doses did not report ulcer healing.Single-study data show similar numbers of participants with reduction in rest pain between BM-MNCs and mPBSCs (RR 0.99, 95% CI 0.93 to 1.06; 104 participants; moderate-quality evidence) and between IM and IA routes (RR 1.22, 95% CI 0.91 to 1.64; 32 participants; low-quality evidence). One study reported no clear difference in rest pain scores between BM-MNC and BM-MSC (MD 0.00, 95% CI -0.61 to 0.61; 37 participants; moderate-quality evidence). Trials comparing high versus low cell doses did not report rest pain.Single-study data show no clear difference in the number of participants with increased ankle-brachial index (ABI; increase of > 0.1 from pretreatment), between BM-MNCs and mPBSCs (RR 1.00, 95% CI 0.71 to 1.40; 104 participants; moderate-quality evidence), and between IM and IA routes (RR 0.93, 95% CI 0.43 to 2.00; 35 participants; very low-quality evidence). In contrast, ABI scores appeared higher in BM-MSC versus BM-MNC groups (MD 0.05, 95% CI 0.01 to 0.09; one RCT, 37 participants; low-quality evidence). ABI was not reported in the high versus low cell dose comparison.Similar numbers of participants had improved transcutaneous oxygen tension (TcO₂) with IM versus IA routes (RR 1.22, 95% CI 0.86 to 1.72; two RCTs, 62 participants; very low-quality evidence). Single-study data with low-quality evidence show a higher TcO₂ reading in BM-MSC versus BM-MNC groups (MD 8.00, 95% CI 3.46 to 12.54; 37 participants) and in mPBSC- versus BM-MNC-treated groups (MD 1.70, 95% CI 0.41 to 2.99; 150 participants). TcO₂ was not reported in the high versus low cell dose comparison.Study authors reported no significant short-term adverse effects attributed to autologous cell implantation.

AUTHORS' CONCLUSIONS

Mostly low- and very low-quality evidence suggests no clear differences between different stem cell sources and different treatment regimens of autologous cell implantation for outcomes such as all-cause mortality, amputation rate, ulcer healing, and rest pain for 'no-option' CLI patients. Pooled analyses did not show a clear difference in clinical outcomes whether cells were administered via IM or IA routes. High-quality evidence is lacking; therefore the efficacy and long-term safety of autologous cells derived from different sources, prepared using different protocols, administered at different doses, and delivered via different routes for the treatment of 'no-option' CLI patients, remain to be confirmed.Future RCTs with larger numbers of participants are needed to determine the efficacy of cell-based therapy for CLI patients, along with the optimal cell source, phenotype, dose, and route of implantation. Longer follow-up is needed to confirm the durability of angiogenic potential and the long-term safety of cell-based therapy.

Stem cell therapy for diabetic foot ulcers: a review of preclinical and clinical research

BACKGROUND

Diabetic foot ulcer (DFU) is a severe complication of diabetes, preceding most diabetes-related amputations. DFUs require over US$9 billion for yearly treatment and are now a global public health issue. DFU occurs in the setting of ischemia, infection, neuropathy, and metabolic disorders that result in poor wound healing and poor treatment options. Recently, stem cell therapy has emerged as a new interventional strategy to treat DFU and appears to be safe and effective in both preclinical and clinical trials. However, variability in the stem cell type and origin, route and protocol for administration, and concomitant use of angioplasty confound easy interpretation and generalization of the results.

METHODS

The PubMed, Google Scholar, and EMBASE databases were searched and 89 preclinical and clinical studies were selected for analysis.

RESULTS

There was divergence between preclinical and clinical studies regarding stem cell type, origin, and delivery techniques. There was heterogeneous preclinical and clinical study design and few randomized clinical trials. Granulocyte-colony stimulating factor was employed in some studies but with differing protocols. Concomitant performance of angioplasty with stem cell therapy showed increased efficiency compared to either therapy alone.

CONCLUSIONS

Stem cell therapy is an effective treatment for diabetic foot ulcers and is currently used as an alternative to amputation for some patients without other options for revascularization. Concordance between preclinical and clinical studies may help design future randomized clinical trials.

Adipose-derived stem cells for treatment of chronic ulcers: current status

Chronic ulcers remain a difficult challenge in healthcare systems. While treatment options are limited, stem cells may be a novel alternative. Adipose-derived stem cells (ADSC) have become increasingly popular compared with bone marrow-derived stem cells as they are far easier to harvest. To summarize the current status of treating chronic ulcers with ADSC, this systematic review includes all clinical trials on the subject from PubMed and EmBase, as well as all registered clinical trials on ClinicalTrials.Gov. A total of nine clinical trials and fourteen registered trials were included. The studies were significantly different in terms of study design and patient population, and the overall quality of the studies was low to moderate. Despite the overall low study quality and the significant differences between the studies, some conclusions were consistent: ADSCs are safe, improve the healing of chronic ulcers, and reduce pain. As these results are consistent despite the shortcomings of the studies, they appear to highlight the efficacy of ADSCs in the treatment of chronic ulcers. Larger numbers of higher quality studies are needed to determine the precise role of ADSCs in treating chronic leg ulcers.