Bioengineered skin in diabetic foot ulcers

Efficient delivery of VEGFA mRNA for promoting wound healing via ionizable lipid nanoparticles

Vascular endothelial growth factor A (VEGFA) plays an important role in the healing of skin wound. However, the application of VEGFA protein in clinic is limited because of its high cost manufacturing, complicated purification and poor pharmacokinetic profile. Herein, we developed nucleoside-modified mRNA encoding VEGFA encapsulated ionizable lipid nanoparticles (LNP) to improve angiogenesis and increase wound healing rate. First, VEGFA mRNA was synthesized by an in vitro transcription (IVT) method. After that, VEGFA mRNA-LNP was prepared by encapsulating mRNA in ionizable lipid based nanoparticles via a microfluidic mixer. The physicochemical properties of VEGFA mRNA-LNP were investigated via dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results showed that the VEGFA mRNA-LNP possessed regular spherical morphology with an average size of 112.67 nm and a negative Zeta potential of -3.43 mV. The LNP delivery system had excellent lysosome escape capability and high transfection efficiency. ELISA and Western Blot analysis indicated that the mRNA-LNP could express VEGFA protein in Human umbilical vein endothelial cells (HUVECs). Besides, endothelial tube formation, cell proliferation and scratch assays were performed. The results revealed VEGFA mRNA-LNP boosted angiogenesis, cell proliferation and cell migration by expressing VEGFA protein. Finally, C57BL/6 mouse model of skin wound was established and intradermally treated with VEGFA mRNA-LNP. The VEGFA mRNA-LNP treated wounds were almost healed with an average wound size of 1.56 mm² compared with the blank of 18.66 mm² after 9 days. The results indicated that the VEGFA mRNA-LNP was able to significantly expedite wound healing. Histological analysis further demonstrated tissue epithelialization, collagen deposition and enhancement of vascular density after treatment. Taken together, VEGFA mRNA-LNP can be uptaken by cells to express protein effectively and promote wound healing, which may provide a promising strategy for clinical remedy.

Effect of composite biodegradable biomaterials on wound healing in diabetes

The repair of diabetic wounds has always been a job that doctors could not tackle quickly in plastic surgery. To solve this problem, it has become an important direction to use biocompatible biodegradable biomaterials as scaffolds or dressing loaded with a variety of active substances or cells, to construct a wound repair system integrating materials, cells, and growth factors. In terms of wound healing, composite biodegradable biomaterials show strong biocompatibility and the ability to promote wound healing. This review describes the multifaceted integration of biomaterials with drugs, stem cells, and active agents. In wounds, stem cells and their secreted exosomes regulate immune responses and inflammation. They promote angiogenesis, accelerate skin cell proliferation and re-epithelialization, and regulate collagen remodeling that inhibits scar hyperplasia. In the process of continuous combination with new materials, a series of materials that can be well matched with active ingredients such as cells or drugs are derived for precise delivery and controlled release of drugs. The ultimate goal of material development is clinical transformation. At present, the types of materials for clinical application are still relatively single, and the bottleneck is that the functions of emerging materials have not yet reached a stable and effective degree. The development of biomaterials that can be further translated into clinical practice will become the focus of research.

Biofilms in Diabetic Foot Ulcers: Impact, Risk Factors and Control Strategies

Diabetic foot ulcers (DFUs) are a serious complication from diabetes mellitus, with a huge economic, social and psychological impact on the patients' life. One of the main reasons why DFUs are so difficult to heal is related to the presence of biofilms. Biofilms promote wound inflammation and a remarkable lack of response to host defences/treatment options, which can lead to disease progression and chronicity. In fact, appropriate treatment for the elimination of these microbial communities can prevent the disease evolution and, in some cases, even avoid more serious outcomes, such as amputation or death. However, the detection of biofilm-associated DFUs is difficult due to the lack of methods for diagnostics in clinical settings. In this review, the current knowledge on the involvement of biofilms in DFUs is discussed, as well as how the surrounding environment influences biofilm formation and regulation, along with its clinical implications. A special focus is also given to biofilm-associated DFU diagnosis and therapeutic strategies. An overview on promising alternative therapeutics is provided and an algorithm considering biofilm detection and treatment is proposed.

Long noncoding RNA H19 acts as a miR-29b sponge to promote wound healing in diabetic foot ulcer

Aberrant expression of long noncoding RNA (lncRNA) H19 and microRNA (miR)-29b has been implicated in the complications of diabetes mellitus (DM). As a common and important complication of DM, diabetic foot ulcer (DFU) is characterized by high incidence and poor prognosis. Herein, we explored the role of lncRNA H19 in wound healing of DFU. Differentially expressed DM-related lncRNAs were initially screened by microarray data analysis. DFU models were then induced in DM mouse models. The functional role and interaction of lncRNA H19, miR-29b and FBN1 in DFU were subsequently determined by examining the proliferation, migration, and apoptosis of fibroblasts after silencing H19, inhibiting or overexpressing miR-29b and FBN1. According to microarray-based analysis, lncRNA H19 was upregulated in DM. In the ulcerative edge tissues of DFU, high expression of lncRNA H19 and FBN1 and low expression of miR-29b were observed. FBN1 was identified to be a target gene of miR-29b. LncRNA H19 could competitively bind to miR-29b, and then, inhibited its expression, which consequently upregulating FBN1. Silencing of lncRNA H19 led to inhibited proliferation, migration, and enhanced apoptosis of fibroblasts, accompanied by downregulated FBN1 but upregulated miR-29b, which diminished the expression of TGF-β1, Smad3, FN, and Col-1 and reduced extracellular matrix accumulation. Altogether, upregulation of lncRNA H19 can elevate the expression of FBN1 through competitively binding to miR-29b, which enhances the proliferation, migration, and inhibits apoptosis of fibroblasts, thus facilitating the wound healing of DFU.

Advances in Dermoepidermal Skin Substitutes for Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are one of the major complications of diabetes, representing a leading cause of hospitalisation and non-traumatic lower limb amputations. Multidisciplinary management, patient education, glucose control, debridement, off-loading, infection control, and adequate perfusion are the mainstays of standard care. Despite all these, at least 30% of DFUs fail to heal within 20 weeks. Therefore, dermoepidermal skin substitutes (DSS) have been used as a new therapeutic adjunct for DFUs. This brief review outlines the recent advances in DSS for the treatment of DFUs. PubMed and Cochrane databases were systematically searched in May to July 2018 for systematic reviews published after 2013 and for randomised controlled trials (RCTs). A retrospective evaluation of 28 RCTs was performed. Rates of complete wound closure and time to healing were examined for 17 commonly available DSS. Healing rates after 12 weeks and time to complete closure in DFUs are heterogeneous among the 28 RCT. The best healing rates at 12 weeks were accomplished with dermal cellular substitutes (Epifix®, 100% and Amnioband®, 85%) and with dermal acellular substitutes (Allopatch®, 80% and Hyalograft®, 78.8%). Based on these studies, DSS used in conjunction with standard care appear to improve the healing rates of DFUs, as compared with standard care alone. Nonetheless, new studies with more homogeneous samples are needed to ascertain the role of ulcer size, duration, depth and/or type in the efficacy of DSS. Moreover, future RCTs should include patients with severe comorbidities, in order to be more representative of clinical reality.

Efficacy and safety of platelet-rich plasma in treating cutaneous ulceration: A meta-analysis of randomized controlled trials

BACKGROUND

The biological mechanisms underlying the use of platelet-rich plasma (PRP), as well as the efficacy and possible adverse effects of PRP, have not yet been fully elucidated. Prior studies have evaluated PRP for cutaneous ulceration. However, the benefits from PRP still remain controversial and few have assessed the effects of ulceration etiologies. The purpose of our study is to determine the efficacy and safety of PRP and which kind of ulcer is more suitable for PRP by analyzing the effects of PRP on ulcers with different causes.

METHODS

A comprehensive search was performed to identify randomized controlled trials (RCTs) regarding the application of PRP from PubMed, EMBASE, Scopus, and the Cochrane Library. The data were analyzed using Review Manager 5.3.

RESULTS

A total of nineteen RCTs (909 patients) were included. In contrast with conventional treatments, PRP achieved higher healing rate, higher percentage of area reduction, and smaller final area in vascular ulcers. However, the advantage disappeared in diabetic and pressure ulcers. Concerning adverse events, PRP showed lower incidence in the short term, but higher in the long term. No significant differences were found in ulcer closure velocity and healing time.

CONCLUSION

Platelet-rich plasma effectiveness and safety in treating cutaneous ulceration depend on what is the ulceration etiology. For diabetic ulcers, PRP showed no satisfactory results suggesting that PRP may not be suitable for diabetic patients. However, PRP could be efficient and more beneficial for vascular ulcers and effects on pressure ulcers remain unclear. Thus, PRP option should be carefully considered for each patient in accordance with their ulceration etiologies.

Diabetic wound management

Diabetes is a global disease, and its prevalence has increased rapidly in the last century. Many complications are associated with diabetes, and diabetic foot ulcers (DFU) are common. There is a variety of different treatments for DFU, and the aim of this article is to discuss the factors responsible for delayed wound healing in patients with diabetes, and the treatment strategies that are available.

Nanosphere-mediated co-delivery of VEGF-A and PDGF-B genes for accelerating diabetic foot ulcers healing in rats

Diabetic ischemic ulcer is an intractable diabetic complication. Angiogenesis is a critical factor for wound healing in patients with diabetic foot wounds. Sustained gene delivery could be notably necessary in modulating gene expression in chronic ulcer healing and might be a promising approach for diabetic foot ulcers. In the present study, Sprague-Dawley rats were used to establish diabetic foot ulcer models by streptozotocin and skin biopsy punch. The plasmids expressing VEGF-A and PDGF-B were prepared and then incorporated with polylactic-co-glycolic acid (PLGA) nanospheres to upregulate genes expression. The aim of this study was to explore whether the engineered VEGF-A and PDGF-B based plasmid-loaded nanospheres could be upregulated in streptozotocin-induced diabetic rats and improve the wound healing. The cultured fibroblasts could be effectively transfected by means of nanosphere/plasmid in vitro. In vivo, the expression of VEGF-A and PDGF-B was significantly upregulated at full-thickness foot dorsal skin wounds and the area of ulceration was progressively and significantly reduced following treatment with nanosphere/plasmid. These results indicated that combined gene transfer of VEGF-A and PDGF-B could improve reparative processes in the wounded skin of diabetic rats and nanosphere may be a potential non-viral vector for gene therapy of the diabetic foot ulcer.

Evaluation of wound healing in diabetic foot ulcer using platelet-rich plasma gel: A single-arm clinical trial

The aim of the present study was to evaluate the effectiveness of using autologous platelet-rich plasma (PRP) gel for treatment of diabetic foot ulcer (DFU) during the first 4 weeks of the treatment. In this longitudinal and single-arm trial, 100 patients were randomly selected after meeting certain inclusion and exclusion criteria; of these 100 patients, 70 (70%) were enrolled in the trial. After the primary care actions such as wound debridement, the area of each wound was calculated and recorded. The PRP therapy (2mL/cm² of ulcers) was performed weekly until the healing time for each patient. We used one sample T-test for healing wounds and Bootstrap resampling approach for reporting confidence interval with 1000 Bootstrap samples. The p-value<0.05 were considered statistically significant. The mean (SD) of DFU duration was 19.71 weeks (4.94) for units sampling. The ratio of subjects who withdrew from the study was calculated to be 2 (2.8%). Average area of 71 ulcers in the mentioned number of cases was calculated to be 6.11cm² (SD: 4.37). Also, the mean, median (SD) of healing time was 8.7, 8 weeks (SD: 3.93) except for 2 mentioned cases. According to one sample T-test, wound area (cm²), on average, significantly decreased to 51.9% (CI: 46.7-57.1) through the first four weeks of therapy. Furthermore, significant correlation (0.22) was not found between area of ulcers and healing duration (p-value>0.5). According to the results, PRP could be considered as a candidate treatment for non-healing DFUs as it may prevent future complications such as amputation or death in this pathological phenomenon.

Localization of human adipose-derived stem cells and their effect in repair of diabetic foot ulcers in rats

Background

Diabetic foot ulcer (DFU) is an intractable diabetic complication. Patients suffering from diabetes mellitus (DM) frequently present with infected DFUs. In this study, a wound healing model on diabetic rat foot was established to mimic the pathophysiology of clinical patients who suffer from DFUs. Our study aimed to explore the localization of human adipose-derived stem cells (hADSCs) and the role of these cells in the repair of foot ulcerated tissue in diabetic rats, and thus to estimate the possibilities of adipose-derived stem cells for diabetic wound therapy.

Method

Sprague–Dawley rats were used to establish diabetic models by streptozotocin injection. A full-thickness foot dorsal skin wound was created by a 5 mm skin biopsy punch and a Westcott scissor. These rats were randomly divided into two groups: the hADSC-treated group and the phosphate-buffered saline (PBS) control group. The hADSC or PBS treatment was delivered through the left femoral vein of rats. We evaluated the localization of hADSCs with fluorescence immunohistochemistry and the ulcer area and ulcerative histology were detected dynamically.

Result

The hADSCs had a positive effect on the full-thickness foot dorsal skin wound in diabetic rats with a significantly reduced ulcer area at day 15. More granulation tissue formation, angiogenesis, cellular proliferation, and higher levels of growth factors expression were also detected in wound beds.

Conclusions

Our data suggest that hADSC transplantation has the potential to promote foot wound healing in diabetic rats, and transplantation of exogenous stem cells may be suitable for clinical application in the treatment of DFU.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0412-2) contains supplementary material, which is available to authorized users.

Cost-Effectiveness of Becaplermin Gel on Diabetic Foot Ulcer HealingChanges in Wound Surface Area

BACKGROUND

A comparison of the cost-effectiveness of becaplermin plus good wound care (BGWC) versus good wound care (GWC) alone in treating patients with diabetic foot ulcers (DFUs) may enable physicians and health-care decision makers in the United States to make better-informed choices about treating DFUs, which currently contribute to a substantial portion of the economic burden of diabetes.

METHODS

Data from three phase III trials were used to predict expected 1-year costs and outcomes, including the average percentage reduction from baseline in wound surface area (WSA), the direct costs of DFU therapy, and the cost per cm(2) of WSA reduction.

RESULTS

At 20 weeks, the BGWC group had a statistically greater probability of complete wound closure than the GWC group (50% versus 35%; P = .015). Based on reported WSA reduction rates, DFUs in the BGWC group were predicted to close by 100% at 27 weeks, and those in the GWC group were predicted to close by 88% at 52 weeks. The GWC group had higher total estimated 1-year direct cost of DFU care ($6,809 versus $4,414) and higher cost per cm(2) of wound closure ($3,501 versus $2,006).

CONCLUSIONS

Becaplermin plus good wound care demonstrated economic dominance compared with GWC by providing better clinical outcomes via faster reduction in WSA and higher rates of closure at a lower direct cost.

Skin grafting and tissue replacement for treating foot ulcers in people with diabetes

BACKGROUND

Foot ulceration is a major problem in people with diabetes and is the leading cause of hospitalisation and limb amputations. Skin grafts and tissue replacements can be used to reconstruct skin defects for people with diabetic foot ulcers in addition to providing them with standard care. Skin substitutes can consist of bioengineered or artificial skin, autografts (taken from the patient), allografts (taken from another person) or xenografts (taken from animals).

OBJECTIVES

To determine the benefits and harms of skin grafting and tissue replacement for treating foot ulcers in people with diabetes.

SEARCH METHODS

In April 2015 we searched: The Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. We also searched clinical trial registries to identify ongoing studies. We did not apply restrictions to language, date of publication or study setting.

SELECTION CRITERIA

Randomised clinical trials (RCTs) of skin grafts or tissue replacements for treating foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of the included studies.

MAIN RESULTS

We included seventeen studies with a total of 1655 randomised participants in this review. Risk of bias was variable among studies. Blinding of participants, personnel and outcome assessment was not possible in most trials because of obvious differences between the treatments. The lack of a blinded outcome assessor may have caused detection bias when ulcer healing was assessed. However, possible detection bias is hard to prevent due to the nature of the skin replacement products we assessed, and the fact that they are easily recognisable. Strikingly, nearly all studies (15/17) reported industry involvement; at least one of the authors was connected to a commercial organisation or the study was funded by a commercial organisation. In addition, the funnel plot for assessing risk of bias appeared to be asymmetrical; suggesting that small studies with 'negative' results are less likely to be published.Thirteen of the studies included in this review compared a skin graft or tissue replacement with standard care. Four studies compared two grafts or tissue replacements with each other. When we pooled the results of all the individual studies, the skin grafts and tissue replacement products that were used in the trials increased the healing rate of foot ulcers in patients with diabetes compared to standard care (risk ratio (RR) 1.55, 95% confidence interval (CI) 1.30 to 1.85, low quality of evidence). However, the strength of effect was variable depending on the specific product that was used (e.g. EpiFix® RR 11.08, 95% CI 1.69 to 72.82 and OrCel® RR 1.75, 95% CI 0.61 to 5.05). Based on the four included studies that directly compared two products, no specific type of skin graft or tissue replacement showed a superior effect on ulcer healing over another type of skin graft or tissue replacement.Sixteen of the included studies reported on adverse events in various ways. No study reported a statistically significant difference in the occurrence of adverse events between the intervention and the control group.Only two of the included studies reported on total incidence of lower limb amputations. We found fewer amputations in the experimental group compared with the standard care group when we pooled the results of these two studies, although the absolute risk reduction for amputation was small (RR 0.43, 95% CI 0.23 to 0.81; risk difference (RD) -0.06, 95% CI -0.10 to -0.01, very low quality of evidence).

AUTHORS' CONCLUSIONS

Based on the studies included in this review, the overall therapeutic effect of skin grafts and tissue replacements used in conjunction with standard care shows an increase in the healing rate of foot ulcers and slightly fewer amputations in people with diabetes compared with standard care alone. However, the data available to us was insufficient for us to draw conclusions on the effectiveness of different types of skin grafts or tissue replacement therapies. In addition, evidence of long term effectiveness is lacking and cost-effectiveness is uncertain.

Cost-effectiveness of becaplermin gel on wound healing of diabetic foot ulcers

We sought to determine the long-term cost effectiveness (payer's perspective) of becaplermin gel plus good wound care (BGWC) vs. good wound care (GWC) alone in terms of wound healing and risk of amputation in patients with diabetic foot ulcers (DFUs). Outcomes data were derived from a propensity score-matched cohort from the Curative Health Services database between 1998 and 2004, which was followed for 20 weeks. A four-state Markov model was used to predict costs and outcomes of wound healing and risk of amputation for BGWC vs. GWC alone over 1 year in patients with DFU. The primary outcome was closed-wound weeks. Transition probabilities for healing and amputation were derived from the aforementioned propensity score-matched cohorts. Ulcer recurrence was estimated from the medical literature. Utilization for becaplermin was calculated using the dosing algorithm in the product labeling. Of 24,898 eligible patients, 9.6% received BGWC. Based on the model, patients treated with BGWC had substantially more closed-wound weeks compared with GWC (16.1 vs. 12.5 weeks, respectively). More patients receiving BGWC had healed wounds at 1 year compared with those receiving GWC (48.1% vs. 38.3%). Risk of amputation was lower in the BGWC cohort (6.8% vs. 9.8%). Expected annual direct costs for DFU were $21,920 for BGWC and $24,640 for GWC. BGWC was economically dominant over GWC, providing better outcomes at a lower cost in patients with DFU. Compared with GWC alone, BGWC is more effective in healing wounds and lowering amputation risk, thereby decreasing long-term costs for DFU.

Literature review on the management of diabetic foot ulcer

Diabetic foot ulcer (DFU) is the most costly and devastating complication of diabetes mellitus, which affect 15% of diabetic patients during their lifetime. Based on National Institute for Health and Clinical Excellence strategies, early effective management of DFU can reduce the severity of complications such as preventable amputations and possible mortality, and also can improve overall quality of life. The management of DFU should be optimized by using a multidisciplinary team, due to a holistic approach to wound management is required. Based on studies, blood sugar control, wound debridement, advanced dressings and offloading modalities should always be a part of DFU management. Furthermore, surgery to heal chronic ulcer and prevent recurrence should be considered as an essential component of management in some cases. Also, hyperbaric oxygen therapy, electrical stimulation, negative pressure wound therapy, bio-engineered skin and growth factors could be used as adjunct therapies for rapid healing of DFU. So, it’s suggested that with appropriate patient education encourages them to regular foot care in order to prevent DFU and its complications.

Diabetic foot ulcer: an evidence-based treatment update

BACKGROUND

Diabetic foot ulcers (DFUs) are extremely debilitating and difficult to treat. Multidisciplinary management, patient education, glucose control, debridement, offloading, infection control, and adequate perfusion are the mainstays of standard care endorsed by most practice guidelines. Adjunctive therapies represent new treatment modalities endorsed in recent years, though many lack significant high-powered studies to support their use as standard of care.

OBJECTIVE

This update intends to identify recent, exclusively high level, evidence-based evaluations of DFU therapies. Furthermore, it suggests a direction for future research.

METHODS

PubMed, Embase, Ovid Technologies, CINAHL, Cochrane, and Web of Science databases were systematically searched for recent systematic reviews published after 2004, and randomized controlled trials published in 2012-2013 that evaluated treatment modalities for DFUs. These papers are reviewed and the quality of available evidence is discussed.

RESULTS

A total of 34 studies met inclusion criteria. Studied therapies include debridement, off-loading, negative pressure therapy, dressings, topical therapies, hyperbaric oxygen therapy, growth factors, bioengineered skin substitutes, electrophysical therapy, and alternative therapy. Good-quality evidence is lacking to justify the use of many of these therapies, with the exception of standard care (offloading, debridement) and possibly negative pressure wound therapy.

LIMITATIONS

There is an overall lack of high-level evidence in new adjunctive management of DFU. Comparison of different treatment modalities is difficult, since existing studies are not standardized.

CONCLUSIONS

Many therapeutic modalities are available to treat DFU. Quality high-level evidence exists for standard care such as off-loading. Evidence for adjunctive therapies such as negative pressure wound therapy, skin substitutes, and platelet-derived growth factor can help guide adjunctive care but limitations exist in terms of evidence quality.

Treating the whole not the hole: necessary coupling of technologies for diabetic foot ulcer treatment

Type 2 diabetes is the epidemic of our generation, and diabetic foot ulcers (DFUs) are a major complication. Although DFU formation itself can indicate disease progression, the failure to effectively treat ulcers contributes further to a decay in patient quality of life and increased mortality. Herein we discuss the development of next-generation DFU therapies including: (i) topical growth factors, (ii) scaffolds, and (iii) cellular therapies. Individually these therapies have yielded measurable but modest improvements in DFU repair. Because DFUs arise as a result of multiple biochemical deficiencies, a singular treatment modality is unlikely to be effective. Next-generation DFU technologies must be combined to address effectively the complex underlying pathology and enable reliable DFU repair.