Efficacy and safety of acellular dermal matrix in diabetic foot ulcer treatment: A systematic review and meta-analysis

Systematic Review of Cellular, Acellular, and Matrix-like Products and Indirect Treatment Comparison Between Cellular/Acellular and Amniotic/Nonamniotic Grafts in the Management of Diabetic Foot Ulcers

Significance: This Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant review focuses on the efficacy of cellular, acellular, and matrix-like products (CAMPs) in the management of diabetic foot ulcers (DFUs) based on published randomized controlled trials (RCTs). Recent Advances: Although CAMPs have been incorporated into the clinical algorithm for chronic wounds, evidence is lacking to comparatively evaluate the efficacy of these products. Critical Issues: Level 1 RCT studies are the gold standard to evaluate the efficacy of different treatment approaches; however, due to differences in surgical techniques, patient demographics, and compliance, standard-of-care (SOC) outcomes in the wound care space can vary significantly between different RCTs, making it difficult to compare them against each other. Future Directions: To mitigate variability between different RCTs, wound closure outcomes can be reported as risk ratios (RRs). This review of all the currently published RCTs (with a similar trial design) in patients with DFU and RRs confirms that CAMPs adjunct to SOC result in statistically superior wound closure outcomes in DFUs, when compared with SOC alone, with a RR of 1.72 [1.56, 1.90], p < 0.00001. Enough evidence is still lacking to determine a statistical difference between broad categories of cellular/acellular and amniotic/nonamniotic CAMPs, and hence, decision makers should consider published head-to-head comparative studies, real-world evidence, and cost-effectiveness evidence between individual CAMPs to decide on which to use in practice.

Recent advances in the adjunctive management of diabetic foot ulcer: Focus on noninvasive technologies

Diabetic foot ulcer (DFU) is one of the most costly and serious complications of diabetes. Treatment of DFU is usually challenging and new approaches are required to improve the therapeutic efficiencies. This review aims to update new and upcoming adjunctive therapies with noninvasive characterization for DFU, focusing on bioactive dressings, bioengineered tissues, mesenchymal stem cell (MSC) based therapy, platelet and cytokine-based therapy, topical oxygen therapy, and some repurposed drugs such as hypoglycemic agents, blood pressure medications, phenytoin, vitamins, and magnesium. Although the mentioned therapies may contribute to the improvement of DFU to a certain extent, most of the evidence come from clinical trials with small sample size and inconsistent selections of DFU patients. Further studies with high design quality and adequate sample sizes are necessitated. In addition, no single approach would completely correct the complex pathogenesis of DFU. Reasonable selection and combination of these techniques should be considered.

Comparative Effectiveness of Placental Allografts in the Treatment of Diabetic Lower Extremity Ulcers and Venous Leg Ulcers in U.S. Medicare Beneficiaries: A Retrospective Observational Cohort Study Using Real-World Evidence

Objective: To compare the effectiveness of cellular tissue products (CTP) versus standard care in U.S. Medicare beneficiaries with diabetic lower extremity ulcers (DLEUs) or venous leg ulcers (VLUs). Approach: We performed a retrospective cohort study using real-world evidence from U.S. Medicare claims for DLEUs or VLUs between 2016 and 2020. There were three cohorts evaluated: viable cryopreserved placental membrane (vCPM) or viable lyopreserved placental membrane (vLPM); other CTP; and standard care. Claims were collapsed into episodes of care. Univariate and bivariate statistics were used to examine the frequency distribution of demographics and clinical variables. Multivariable zero-inflated binomial regressions were used to evaluate mortality and recurrence trends. Logistic regression compared three adverse outcomes (AOs): amputation; 1-year mortality; and wound recurrence. Results: There were 333,362 DLEU episodes among 261,101 beneficiaries, and 122,012 VLU episodes among 80,415 beneficiaries. DLEU treatment with vLPM was associated with reduced 1-year mortality (-26%), reduced recurrence (-91%), and reduced AOs (-71%). VLU treatment with vCPM or vLPM was associated with reduced 1-year mortality (-23%), reduced recurrence (-80%), and 66.77% reduction in AOs. These allografts were also associated with a 49% and 73% reduced risk of recurrence in DLEU and VLU, respectively, compared with other CTPs. Finally, vCPM or vLPM were associated with noninferior prevention of AOs related to amputation, mortality, and recurrence (95% CI: 0.69-1.14). Conclusions: DLEUs and VLUs treated with vCPM and vLPM allografts are associated with lowered 1-year mortality, wound recurrence, and AOs in DLEUs and VLUs compared with standard care. Decision makers weighing coverage of placental allografts should consider these added short- and long-term clinical benefits relative to costly management and high mortality of Medicare's most frequent wounds.

Treatment of hard-to-heal wounds in ischaemic lower extremities with a novel fish skin-derived matrix

OBJECTIVE

To evaluate the efficacy of treatment of hard-to-heal wounds of patients with ischaemia of the lower extremities, and compare an omega-3 wound matrix product (Kerecis, Iceland) with a standard dressing.

METHOD

A single-centre, prospective, randomised, controlled clinical trial of patients with hard-to-heal wounds following three weeks of standard care was undertaken. The ischaemic condition of the wound was confirmed as a decreased transcutaneous oxygen pressure (TcPO2) of <40mmHg. After randomising patients into either a case (omega-3 dressing) or a control group (standard dressing), the weekly decrease in wound area over 12 weeks and the number of patients that achieved complete wound closure were compared between the two groups. Patients with a TcPO2 of ≤32mmHg were taken for further analysis of their wound in a severe ischaemic context.

RESULTS

A total of 28 patients were assigned to the case group and 22 patients to the control group. Over the course of 12 weeks, the wound area decreased more rapidly in the case group than the control group. Complete wound healing occurred in 82% of patients in the case group and 45% in the control group. Even in patients with a severe ischaemic wound with a TcPO2 value of <32 mmHg, wound area decreased more rapidly in the case group than the control group. The proportions of re-epithelialised area in the case and control groups were 80.24% and 57.44%, respectively.

CONCLUSION

Considering the more rapid decrease in wound area and complete healing ratio in the case group, application of a fish skin-derived matrix for treating lower-extremity hard-to-heal wounds, especially with impaired vascularity, would appear to be a good treatment option.

Statistical fragility of outcomes in acellular dermal matrix literature: A systematic review of randomized controlled trials

BACKGROUND

Acellular dermal matrix (ADM) is commonly used in plastic and reconstructive surgery. With the abundance of randomized controlled trials (RCTs) reporting P-values for ADM outcomes, this study used the fragility index (FI), reverse fragility index (rFI), and fragility quotient (FQ) to evaluate the statistical stability of the outcomes in ADM RCTs.

METHODS

PubMed, Embase, SCOPUS, Medline, and Cochrane databases were reviewed for ADM RCTs (2003-present) reporting a dichotomous, categorical outcome. FI and rFI (event reversals influencing outcome significance) and FQ (standardized fragility) were calculated and reported as median. Subgroup analysis was performed based on intervention types.

RESULTS

Among the 127 studies screened, 56 RCTs with 579 outcomes were included. The median FI stood at 4 (3-5) and FQ was 0.04 (0.03-0.07). Only 101 outcomes were statistically significant with a median FI of 3 (1-6) and FQ of 0.04 (0.02-0.08). The nonsignificant outcomes had a median FI of 4 (3-5) and FQ of 0.04 (0.03-0.07). Notably, 26% of the outcomes had several patients lost to follow up equal to or surpassing the FI. Based on the intervention type, the median FIs showed minor fluctuations but remained low.

CONCLUSIONS

Outcomes from ADM-related RCTs were statistically fragile. Slight outcome reversals or maintenance of patient follow-up can alter the significance of results. Therefore, future researchers are recommended to jointly report FI, FQ, and P-values to offer a comprehensive view of the robustness in ADM literature.

Cost effectiveness analysis for commonly used human cell and tissue products in the management of diabetic foot ulcers

Background and Aims

This study considers the cost-effectiveness of commonly used cellular, acellular, and matrix‑like products (CAMPs) of human origin also known as human cell and tissue products (HCT/Ps) in the management of diabetic foot ulcers.

Methods

We developed a 1-year economic model assessing six CAMPs [cryopreserved placental membrane with viable cells (vCPM), bioengineered bilayered living cellular construct (BLCC), human fibroblast dermal substitute (hFDS), dehydrated human amnion chorion membrane (dHACM), hypothermically stored amniotic membrane (HSAM) and human amnion membrane allograft (HAMA) which had randomized controlled trial evidence compared with standard of care (SoC). CAMPs were compared indirectly and ranked in order of cost-effectiveness using SoC as the baseline, from a CMS/Medicare's perspective.

Results

The mean cost, healed wounds (hw) and QALYs per patient for vCPM is $10,907 (0.914 hw, 0.783 QALYs), for HAMA $11,470 (0.903 hw, 0.780 QALYs), for dHACM $15,862 (0.828 hw, 0.764 QALYs), for BLCC $18,430 (0.816 hw, 0.763 QALYs), for hFDS $19,498 (0.775 hw, 0.757 QALYs), for SoC $19,862 (0.601 hw, 0.732 QALYs) and $24, 214 (0.829, 0.763 QALYs) for HSAM respectively. Over 1 year, vCPM results in cheaper costs overall and better clinical outcomes compared to other CAMPs. Following probabilistic sensitivity analysis, vCPM has a 60%, HAMA 40% probability of being cost-effective then dHACM, hFDS, BLCC, and lastly HSAM using a $100,000/healed wound or QALY threshold.

Conclusions

All CAMPs were shown to be cost-effective when compared to SoC in managing DFUs. However, vCPM appears to be the most cost-effective CAMP over the modelled 52 weeks followed by HAMA, dHACM, hFDS, BLCC, and HSAM. We urge caution in interpreting the results because we currently lack head-to-head evidence comparing all these CAMPs and therefore suggest that this analysis be updated when more direct evidence of CAMPs becomes available.

Effectiveness and safety of dermal matrix used for diabetic foot ulcer: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Diabetic foot ulcers (DFUs) have become a global health concern, which can lead to diabetic foot infection (DFI), lower leg amputation, and even mortality. Though the standard of care (SOC) practices have been recognized as the "gold standard" for DFU care, SOC alone may not be adequate to heal all DFUs and prevent their recurrence. The use of dermal matrix has emerged as an adjuvant treatment to enhance DFU healing. The current study aimed to evaluate the effectiveness and safety of dermal matrix application as an adjuvant treatment to the SOC.

METHODS

The databases of PubMed, Embase and CENTRAL were independently searched by two authors, with the following key terms: "diabetic foot ulcer", "acellular dermal matrix", "wound healing", and so on. Randomized controlled trials (RCTs) evaluated the efficacy and safety of dermal matrix in the treatment of DFUs were eligible for inclusion. The primary outcomes analyzed included time to complete healing and complete healing rate at the final follow-up, while secondary outcomes included wound area, ulcer recurrence rate, amputation risk and complication risk. Meta-analyses were performed using random-effect or fixed-effect models, based on the heterogeneity test.

RESULTS

This study included a total of 15 RCTs with a total of 1524 subjects. Of these, 689 patients were treated with SOC alone, while 835 patients received SOC plus dermal matrix. Compared to the SOC group, significantly shorter time (MD = 2.84, 95%CI: 1.37 ~ 4.32, p < 0.001***) was required to achieve complete healing in dermal matrix group. Significantly higher complete healing rate (OR = 0.40, 95%CI: 0.33 ~ 0.49, p < 0.001***) and lower overall (RR = 1.83, 95%CI: 1.15 ~ 2.93, p = 0.011*) and major (RR = 2.64, 95%CI: 1.30 ~ 5.36, p = 0.007**) amputation risks were achieved in dermal matrix group compared to SOC group. No significant difference was found in the wound area, ulcer recurrence rate, and complication risk between the two groups.

CONCLUSIONS

The application of dermal matrix as an adjuvant therapy in conjunction with SOC effectively improved the healing process of DFUs and reduced the amputation risk when compared to SOC alone. Furthermore, dermal matrix application was well tolerated by the subjects with no added complication risk.

Early identification of delayed wound healing in complex diabetic foot ulcers treated with a dermal regeneration template: a novel clinical target and its risk factors

BACKGROUND

The dermal regeneration template (DRT), a tissue-engineered skin substitute composing a permanent dermal matrix and an upper temporary silicone layer that serves as the epidermis, has demonstrated efficacy in treating uncomplicated diabetic foot ulcers (DFUs). Our institution has obtained good outcomes with DRT in patients with more complicated DFUs. Because of its chronicity, the authors are working to identify a clinical target that anticipates delayed healing early in the treatment in addition to determining the risk factors linked to this endpoint to increase prevention.

MATERIALS AND METHODS

This retrospective single-center study analyzed patients with DFUs who underwent wound reconstruction using DRT between 2016 and 2021. The patients were categorized into poor or good graft-take groups based on their DRT status on the 21st day after the application. Their relationship with complete healing (CH) rate at day 180 was analyzed. Variables were collected for risk factors for poor graft take at day 21. Independent risk factors were identified after multivariable analysis. The causes of poor graft take were also reported.

RESULTS

This study examined 80 patients (38 and 42 patients in the poor and good graft-take groups, respectively). On day 180, the CH rate was 86.3% overall, but the poor graft-take group had a significantly lower CH rate (76.3 vs. 95.2%, P =0.021) than the good graft-take group. Our analysis identified four independent risk factors: transcutaneous oxygen pressure less than 30 mmHg (odds ratio, 154.14), off-loading device usage (0.03), diabetic neuropathy (6.51), and toe wound (0.20). The most frequent cause of poor graft take was infection (44.7%), followed by vascular compromise (21.1%) and hematoma (15.8%).

CONCLUSION

Our study introduces the novel concept of poor graft take at day 21 associated with delayed wound healing. Four independent risk factors were identified, which allows physicians to arrange interventions to mitigate their effects or select patients more precisely. DRT represents a viable alternative to address DFUs, even in complicated wounds. A subsequent split-thickness skin graft is not always necessary to achieve CH.

Objective Non-Invasive Bio-Parametric Evaluation of Regenerated Skin: A Comparison of Two Acellular Dermal Substitutes

Several dermal substitutes are available on the market, but there is no precise indication that helps surgeons choose the proper one. Few studies have tried to compare different xenogeneic bioengineered products, but no objective bio-parametric comparison has been made yet. Fifteen patients who underwent skin reconstruction with Integra® or Pelnac® were retrospectively evaluated. After at least 12 months of follow-up, an objective and quantitative assessment of several skin biophysical properties, such as color, texture, elasticity, hydration, glossiness and trans-epidermal water loss, were measured with non-invasive skin measurement devices. The grafted skin showed a reduction of the superficial hydration level and a tendency to lower values of trans-epidermal water loss with both dermal substitutes. Melanic and hemoglobin pigmentation were higher in comparison to the donor site in both groups, while a melanic pigmentation increase versus the surrounding skin was seen just with Integra®. Finally, the skin was found to be more elastic when reconstructed with Integra®. The skin barrier appeared to be intact in both groups. Hence, these substitutes are valuable means of skin regeneration. Integra® seems to be more advantageous for reconstructing areas that need more skin flexibility.

Diabetic Foot Ulcer Management and Treatment: An Overview of Published Patents

BACKGROUND

One of the most challenging effects of diabetes is diabetic foot ulceration (DFU). DFU may occur in up to one-third of individuals with diabetes mellitus (D.M.) at some point in their lives. The major cause of morbidity in D.M. patients is DFU. The length of treatment is difficult, and DFU recurrence is common.

OBJECTIVE

The most crucial element for the treatment and prevention of DFUs require a multidisciplinary approach. Patients who are at risk should be identified, depending on the type of risk, prophylactic actions etc. It is imperative to identify at-risk patients and take preventative measures accordingly.

METHOD

The at-risk diabetes-related foot ulcer was identified based on the risk category classification, while the foot ulcers were evaluated using Wagner's classification system.

RESULTS

Literature reported that patients with lower limb vascular insufficiency, loss of vibratory sensation, or protective sensation loss have an increased risk of developing foot ulcers. Proper categorization and therapeutic measures will be implemented after the DFU has been formed. The appropriate assessment and management of general health status should include glycemic control, the diagnosis and treatment of vascular disease, standard care for wounds, diagnosis, and infection treatments.

CONCLUSION

The review reflects the updated awareness of the treatment and management of DFU based on the current and past literature and patent analysis.

Mechanical properties of the rabbit and human decellularized patches for well-tolerated/reinforced organ in cardiac tissue engineering

Introduction

Natural decellularized patches have been developed as the therapeutic platform for the treatment of different diseases, especially cardiovascular disorders. Decellularized scaffolds (as both cell-seeded and cell-free patches) are broadly studied in heart tissue redevelopment in vivo and in vitro. The designed regenerative bio-scaffold must have desirable physicochemical properties including mechanical stiffness for load-bearing, and appropriate anatomical characteristics to mimic the native biological environment properly and facilitate tissue reconstruction. In this context, the current study was designed to investigate rabbit decellularized derma's similarity with human decellularized skin in terms of mechanical properties for cardiac tissue engineering application.

Methods

Fifty two rabbit dermal specimens were provided and divided into two groups: the experimental (decellularized) group and the control (group). Similarly, twelve human skin specimens were divided into the experimental (decellularized) and control groups. Initially, the effect of decellularization on the mechanical performance of scaffolds was analyzed. Then, the mechanical strength of decellularized rabbit skin was compared to decellularized human derma by measuring the stress strain and Young's modulus of the samples.

Results

The results showed that rabbit decellularized skin has a similar elastic range to human decellularized skin, despite being more elastic (P>0.05). In addition, after decellularization, both rabbit and human skin showed a non-significant decrease in elasticity (P>0.05). It is worth noting that the elasticity reduction in rabbit samples after skin decellularization was lower than in human samples.

Conclusion

According to the results of this study and the similarities of rabbit decellularized derm to human skin and its advantages over it, along with the biological complexity of native cardiac ECM, this scaffold can be used as an alternative matrix for tissue-engineered cardiac patches.

Multifunctional ADM hydrogel containing endothelial cell-exosomes for diabetic wound healing

Non-healing wound, with limited treatment options, remains a prevalent complication of diabetes mellitus. The underlying causes wherein include oxidative stress injury, bacterial infection, cellular dysfunction, and persistent inflammation. Acellular Dermal Matrix (ADM), a wound dressing composed of natural extracellular matrix and abundant bioactive factors, has been successfully developed to treat various wounds, including burns and diabetic ulcers. Protocatechualdehyde (PA) & trivalent iron ion (Fe3+) complex (Fe3+@PA) exhibits potential antioxidant and antibacterial properties. In this study, we developed a dual hydrogel network by combining Fe3+@PA complex-modified ADM with light-cured gelatin (GelMA), supplemented with exosomes derived from human umbilical vein endothelial cells (HUVEC-Exos), to create an ADM composite hydrogel system (ADM-Fe3+@PA-Exos/GelMA) with antioxidant, antibacterial, and cell-promoting functions for diabetic wound treatment. Through in vitro experiments, we investigated the biosafety, antioxidant and antibacterial properties of ADM composite hydrogel. Furthermore, we examined the protective effects of ADM composite hydrogel on diabetic wound. The above experiments collectively demonstrate that our ADM-Fe3+@PA-Exos/GelMA hydrogel promotes diabetic wound healing by eliminating bacterial infection, reduced the reactive oxygen species (ROS) levels, protecting cells against oxidative stress damage, promotingcollagen deposition and angiogenesis, which provides a promising strategy to optimize ADM for diabetic wound treatment.

Acellular Dermal Matrix for Treatment of Diabetic Foot Ulcer: An Overview of Systematic Reviews

Aims: To evaluate the reliability of the methodological quality and outcome measures of systematic reviews (SRs)/metaanalyses (MAs) of the acellular dermal matrix (ADM) for diabetic foot ulcer (DFU). Methods: We searched and retrieved SRs and MAs on the application of ADM for DFU from PubMed, Web of Science, The Cochrane Library, EMBASE, CNKI, CBM, WanFang, and VIP databases. We employed AMSTAR 2 to assess methodological quality, Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to grade, and the strength of evidence of included SRs/MAs. We excluded the overlapping randomized controlled trials (RCTs) and conducted a re-MA of the primary RCTs. Results: A total of 7 SRs/MAs were included. Results from the AMSTAR 2 evaluation revealed a low overall quality; the GRADE system showed that the evidence was of moderate to very low quality. Our re-MA showed that ADM was superior to standard of care (SOC), with regards to complete wound healing rate at 12 weeks (RR = 1.74, 95% CI:1.34-2.25, P < .0001), complete wound healing rate at 16 weeks (RR = 1.50, 95% CI: 1.26-1.77, P ＜ .00001); healing time (MD = -2.06, 95% CI: -2.57 to -1.54, P < .00001) and adverse events (RR = 0.62, 95% CI: 0.49-0.80, P = .0002). However, a consensus has not yet been reached between ADM and SOC groups with regard to outcome indicators of the reduction of ulcer area and quality of life; and subgroup analyses showed no statistically significant differences between the xenograft ADM and SOC groups (RR = 1.36, 95% CI: 0.95-1.93, P = .09) at 12 weeks. Conclusion: Current evidence suggests that ADM is more effective than the standard of care in the treatment of DFU, particularly for full-thickness, noninfected, and nonischemic foot ulcers, but with low evidence quality. Therefore, the results of this overview should be interpreted dialectically and prudently, and the role of ADM in DFU needs further exploration.

Copper-Epigallocatechin Gallate Enhances Therapeutic Effects of 3D-Printed Dermal Scaffolds in Mitigating Diabetic Wound Scarring

Morbid dermal templates, microangiopathy, and abnormal inflammation are the three most critical reasons for the scarred healing and the high recurrence rate of diabetic wounds. In this present study, a combination of a methacrylated decellularized extracellular matrix (ECMMA, aka EM)-based hydrogel system loaded with copper-epigallocatechin gallate (Cu-EGCG) capsules is proposed to fabricate bio-printed dermal scaffolds for diabetic wound treatment. Copper ions act as a bioactive element for promoting angiogenesis, and EGCG can inhibit inflammation on the wound site. In addition to the above activities, EM/Cu-EGCG (E/C) dermal scaffolds can also provide optimized templates and nutrient exchange space for guiding the orderly deposition and remodeling of ECM. In vitro experiments have shown that the E/C hydrogel can promote angiogenesis and inhibit the polarization of macrophages to the M1 pro-inflammatory phenotype. In the full-thickness skin defect model of diabetic rats, the E/C dermal scaffold combined with split-thickness skin graft transplantation can alleviate pathological scarring via promoting angiogenesis and driving macrophage polarization to the anti-inflammatory M2 phenotype. These may be attributed to the scaffold-actuated expression of angiogenesis-related genes in the HIF-1α/vascular endothelial growth factor pathway and decreased expression of inflammation-related genes in the TNF-α/NF-κB/MMP9 pathway. The results of this study show that the E/C dermal scaffold could serve as a promising artificial dermal analogue for solving the problems of delayed wound healing and reulceration of diabetic wounds.

Composite Hydrogels of Ultrasound-Assisted-Digested Formic Acid-Decellularized Extracellular Matrix and Sacchachitin Nanofibers Incorporated with Platelet-Rich Plasma for Diabetic Wound Treatment

In this study, an ultrasound-assisted digestion method of a formic acid-decellularized extracellular matrix (dECM) of porcine skin was developed and optimized to form UdECM hydrogels for diabetic wound healing. Results demonstrated that ultrasonication improved the extraction rate of collagen from dECM samples, preserved the collagen content of dECM, reduced residual cells, and extracted greater DNA contents. Scanning electron microscope (SEM) analyses were performed, which demonstrated the optimal porosity on the surface and density of the cross-section in the hydrogel structure, which could control the release of growth factors embedded in UdECM hydrogels at desirable rates to boost wound healing. A wound-healing study was conducted with six different composite hydrogels, both empty materials and materials enriched with rat platelet-rich plasma (R-PRP), sacchachitin nanofibers (SCNFs), and TEMPO-oxidized sacchachitin in diabetic rats. The assessment based on scars stained with hematoxylin and eosin (H&E), Masson's trichrome (MT), and a cluster of differentiation 31 (CD31) staining showed that the UdECM/SC/R-PRP treatment group had the most significant efficacy of promoting healing and even recovery of diabetic wounds to normal tissues. UdECM/R-PRP and UdECM/SCNFs demonstrated better healing rates than UdECM hydrogel scaffolds, which had only recovered 50% resemblance to normal skin. Treatment with both UdECM/TEMPO 050 and UdECM/TEMPO 050/R-PRP hydrogel scaffolds was ranked last, with even poorer efficacy than UdECM hydrogels. In summary, formulated UdECM and SCNF hydrogels loaded with PRP showed synergistic effects of accelerating wound healing and ultimately stimulating the wound to recover as functional tissues. This newly UdECM/SCNF composite hydrogel has promising potential for healing and regenerating diabetic wounds.

Autologous Skin Grafts, versus Tissue-engineered Skin Constructs: A Systematic Review and Meta-analysis

For over 100 years, autologous skin grafts have remained the gold standard for the reconstruction of wounds but are limited in availability. Acellular tissue-engineered skin constructs (acellular TCs) and cellular tissue-engineered skin constructs (cellular TCs) may address these limitations. This systematic review and meta-analysis compare outcomes between them.

Methods

A systematic review was conducted using PRISMA guidelines, querying MEDLINE, Embase, Web of Science, and Cochrane to assess graft incorporation, failure, and wound healing. Case reports/series, reviews, in vitro/in vivo work, non-English articles or articles without full text were excluded.

Results

Sixty-six articles encompassing 4076 patients were included. No significant differences were found between graft failure rates (P = 0.07) and mean difference of percent reepithelialization (p = 0.92) when split-thickness skin grafts were applied alone versus co-grafted with acellular TCs. Similar mean Vancouver Scar Scale was found for these two groups (p = 0.09). Twenty-one studies used at least one cellular TC. Weighted averages from pooled results did not reveal statistically significant differences in mean reepithelialization or failure rates for epidermal cellular TCs compared with split-thickness skin grafts (p = 0.55).

Conclusions

This systematic review is the first to illustrate comparable functional and wound healing outcomes between split-thickness skin grafts alone and those co-grafted with acellular TCs. The use of cellular TCs seems promising from preliminary findings. However, these results are limited in clinical applicability due to the heterogeneity of study data, and further level 1 evidence is required to determine the safety and efficacy of these constructs.

Converting Acellular Dermal Matrix into On-Demand Versatile Skin Scaffolds by a Balanceable Crosslinking Approach for Integrated Infected Wounds Therapy

Ideal tissue-engineered skin scaffolds should possess integrated therapeutic effects and multifunctionality, such as broad-spectrum antibacterial properties, adjustable mechanical properties, and bionic structure. Acellular dermal matrix (ADM) has been broadly used in many surgical applications as an alternative treatment to the "gold standard" tissue transplantation. However, insufficient broad-spectrum antibacterial and mechanical properties for therapeutic efficacy limit the practical clinical applications of ADM. Herein, a balanceable crosslinking approach based on oxidized 2-hydroxypropyltrimethyl ammonium chloride chitosan (OHTCC) was developed for converting ADM into on-demand versatile skin scaffolds for integrated infected wounds therapy. Comprehensive experiments show that different oxidation degrees of OHTCC have significative influences on the specific origins of OHTCC-crosslinked ADM scaffolds (OHTCC-ADM). OHTCC with an oxidation degree of about 13% could prosperously balance the physiochemical properties, antibacterial functionality, and cytocompatibility of the OHTCC-ADM scaffolds. Owing to the natural features and comprehensive crosslinking effects, the proposed OHTCC-ADM scaffolds possessed the desirable multifunctional properties, including adjustable mechanical, degradable characteristics, and thermal stability. In vitro/in vivo biostudies indicated that OHTCC-ADM scaffolds own well-pleasing broad-spectrum antibacterial performances and play effectively therapeutic roles in treating infection, inhibiting inflammation, promoting angiogenesis, and promoting collagen deposition to enhance the infected wound healing. This study proposes a facile balanceable crosslinking approach for the design of ADM-based versatile skin scaffolds for integrated infected wounds therapy.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

E2F2 Promotes Wound Healing of Diabetic Foot Ulcer by Regulating CDCA7L Transcription

OBJECTIVE

The E2F2 transcription factor can accelerate cell proliferation and wound healing. However, its mechanism of action in a diabetic foot ulcer (DFU) remains unclear. Therefore, this study explores the influence of E2F2 on wound healing in DFU by examining cell division cycle-associated 7-like (CDCA7L) expression.

METHODS

CDCA7L and E2F2 expression in DFU tissues were analyzed with databases. CDCA7L and E2F2 expression were altered in human umbilical vein endothelial cells (HUVECs) and spontaneously transformed human keratinocyte cell culture (HaCaT) cells. Cell viability, migration, colony formation, and angiogenesis were evaluated. Binding of E2F2 to the CDCA7L promoter was examined. Subsequently, a diabetes mellitus (DM) mouse model was established and treated with full-thickness excision followed by CDCA7L overexpression. Wound healing in these mice was observed and recorded, and vascular endothelial growth factor receptor 2 (VEGFR2) and hematopoietic progenitor cell antigen CD34 (CD34) expression were determined. E2F2 and CDCA7L expression levels in cells and mice were evaluated. The expression of growth factors was tested.

RESULTS

CDCA7L expression was downregulated in DFU tissues and wound tissues from DM mice. Mechanistically, E2F2 bound to the CDCA7L promoter to upregulate CDCA7L expression. E2F2 overexpression enhanced viability, migration, and growth factor expression in HaCaT cells and HUVECs, and augmented HUVEC angiogenesis and HaCaT cell proliferation, which was nullified by silencing CDCA7L. In DM mice, CDCA7L overexpression facilitated wound healing and elevated the expression level of growth factors.

CONCLUSIONS

E2F2 facilitated cell proliferation and migration and fostered wound healing in DFU cells through binding to the CDCA7L promoter.

One-Stage Immediate Alloplastic Breast Reconstruction in Large and Ptotic Breasts: An Institutional Algorithm

Immediate implant-based breast reconstruction in patients with large and ptotic breasts may be challenging due to skin redundancy. The use of a reduction mammoplasty pattern for the mastectomy skin excision has proven to be a reliable option for these patients as it allows for a better shape, projection, and symmetrization. This approach has been described in the literature for both one- and two-stage reconstruction with either sub- or pre-pectoral reconstruction with an acellular dermal matrix (ADM) or non-biological mesh. One-stage immediate breast reconstructions have a positive significant impact on patients' psychosocial well-being and quality of life. The purpose of this paper is to describe an institutional algorithm that allows one to perform one-stage implant-based breast reconstructions in patients with large and ptotic breasts.

A long‐term follow‐up study of diabetic foot ulcer using micronized acellular dermal matrix

Treating a diabetic foot ulcer (DFU) extending to the tendon or bone can be a challenge for physicians. Recent studies have shown positive results of micronized acellular dermal matrix (ADM) treatment for treating DFU. However, studies on such ADM with a long-term follow-up are rare. Thus, the objective of this study was to retrospectively analyse patients treated with micronized ADM with a long-term follow-up to assess the effectiveness of the treatment and determine the recurrence rate. The rate of success of complete healing was 62.96% and the time of complete healing was 86.96 days in this study. The recurrence rate of DFUs was 41.17% in the overall group. However, it was only 23.52% in the micronized ADM group. The average duration of recurrence was 720.50 ± 505.12 days. The recurrence rate was 50% in weight bearing areas such as the plantar and heel. It was 12.5% in toes and non-weight bearing areas. In conclusion, micronized ADM can be used to effectively treat DFUs that have invaded ligaments or bones. A close follow-up of weight bearing area wounds will allow us to identify and treat recurrence early.

Advances on the modification and biomedical applications of acellular dermal matrices

Acellular dermal matrix (ADM) is derived from natural skin by removing the entire epidermis and the cell components of dermis, but retaining the collagen components of dermis. It can be used as a therapeutic alternative to “gold standard” tissue grafts and has been widely used in many surgical fields, since it possesses affluent predominant physicochemical and biological characteristics that have attracted the attention of researchers. Herein, the basic science of biologics with a focus on ADMs is comprehensively described, the modification principles and technologies of ADM are discussed, and the characteristics of ADMs and the evidence behind their use for a variety of reconstructive and prosthetic purposes are reviewed. In addition, the advances in biomedical applications of ADMs and the common indications for use in reconstructing and repairing wounds, maintaining homeostasis in the filling of a tissue defect, guiding tissue regeneration, and delivering cells via grafts in surgical applications are thoroughly analyzed. This review expectedly promotes and inspires the emergence of natural raw collagen-based materials as an advanced substitute biomaterial to autologous tissue transplantation.

Graphical Abstract

MXenes-integrated microneedle combined with asiaticoside to penetrate the cuticle for treatment of diabetic foot ulcer

Patients with diabetic foot ulcers usually suffer from inefficient epithelisation and angiogenesis accompanied by chronic wound healing. Diabetic foot ulcers remain a major challenge in clinical medicine; however, traditional treatments are incapable of transdermal drug delivery, resulting in a low drug delivery rate. We report the development of Ti2C3 MXenes-integrated poly-γ-glutamic acid (γ-PGA) hydrogel microneedles to release asiaticoside (MN-MXenes-AS). Asiaticoside was loaded into PGA-MXenes hydrogel to facilitate cell proliferation while regulating angiogenesis. The characterisation and mechanical strength of the microneedles were investigated in vitro, and the wound-healing efficacy of the microneedles was confirmed in diabetic mice. MXenes significantly improved the mechanical strength of microneedles, while γ-PGA hydrogels provided a moist microenvironment for wound healing. Mice treated with MN-MXenes-AS demonstrated obvious improvements in wound healing process. We successfully fabricated an MXenes-integrated microneedle that possesses sufficient rigidity to penetrate the cuticle for subcutaneous drug delivery, thereby accelerating diabetic wound healing. We demonstrated that MN-MXenes-AS is effective in promoting growth both in vivo and in vitro. Collectively, our data show that MN-MXenes-AS accelerated the healing of diabetic foot ulcers, supporting the use of these microneedles in the treatment of chronic wounds.

Graphical Abstract

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.

Use of injectable acellular dermal matrix combined with negative pressure wound therapy in open diabetic foot amputation

Objective:

Skin grafts after negative pressure wound therapy (NPWT) and acellular dermal matrix (ADM) usage have both been useful for treating diabetic foot amputation. We hypothesised that injectable ADM combined with NPWT would be more useful than NPWT only for healing after amputation in patients with diabetic foot ulcers (DFUs). The aim of this study was to investigate the clinical outcomes of injectable ADM combined with NPWT in patients with DFU who have undergone amputation.

Method:

This retrospective study reviewed patients with infected DFUs who were administered NPWT. Patients were divided into two groups: Group 1 included patients who were treated with NPWT only, while Group 2 included patients who were treated with injectable ADM combined with NPWT. Clinical results including the number of NPWT dressing changes, wound healing duration, and full-thickness skin graft (FTSG) incident rate between the two groups were compared.

Results:

A total of 41 patients took part in the study (Group 1=20, Group 2=21). The mean number of NPWT dressing changes was significantly lower in Group 2 (8.71±3.77) than in Group 1 (13.90±5.62) (p=0.001). Mean wound healing period was shorter in Group 2 (3.17±1.36 weeks) than in Group 1 (5.47±1.68 weeks) (p=0.001). Finally, the rate of patients who underwent FTSG for complete wound closure was 85% in Group 1, whereas it was only 14.3% in Group 2.

Conclusion:

In this study, the use of injectable ADM combined with NPWT in patients with DFU who underwent amputation favoured complete wound healing, without the need to resort to the use of skin grafts.

Use of a purified reconstituted bilayer matrix in the management of chronic diabetic foot ulcers improves patient outcomes vs standard of care: Results of a prospective randomised controlled multi-centre clinical trial

Diabetic foot infections continue to be a major challenge for health care delivery systems. Following encouraging results from a pilot study using a novel purified reconstituted bilayer matrix (PRBM) to treat chronic diabetic foot ulcers (DFUs), we designed a prospective, multi‐centre randomised trial comparing outcomes of PRBM at 12 weeks compared with a standard of care (SOC) using a collagen alginate dressing. The primary endpoint was percentage of wounds closed after 12 weeks. Secondary outcomes included assessments of complications, healing time, quality of life, and cost to closure. Forty patients were included in an intent‐to‐treat (ITT) and per‐protocol (PP) analysis, with 39 completing the study protocol (n = 19 PRBM, n = 20 SOC). Wounds treated with PRBM were significantly more likely to close than wounds treated with SOC (ITT: 85% vs 30%, P = .0004, PP: 94% vs 30% P = .00008), healed significantly faster (mean 37 days vs 67 days for SOC, P = .002), and achieved a mean wound area reduction within 12 weeks of 96% vs 8.9% for SOC. No adverse events (AEs) directly related to PRBM treatment were reported. Mean PRBM cost of healing was $1731. Use of PRBM was safe and effective for treatment of chronic DFUs.

Use of Biodegradable Temporising Matrix (BTM) in the reconstruction of diabetic foot wounds: A pilot study

Introduction

Complex diabetes-related foot wounds are at high risk of infection and subsequent major amputation unless healed expediently. Biodegradable Temporising Matrix (BTM) is a synthetic matrix that facilitates the organisation of the extracellular matrix, resulting in a neodermis layer over these difficult-to-heal areas. The aim of this study was to evaluate the efficacy of using BTM in the reconstruction of challenging diabetic foot wounds.

Methods

Eighteen patients with complex diabetic foot wounds (exposed tendon, fascia, joint, bone), or chronic ulcers at high shear stress locations had BTM applied. Indications for BTM application were high shear stress location (66.6%), exposed bone (16.6%), exposed fascia (5.6%), exposed tendon (5.6%) and chronic non-healing wound (5.6%). The time to complete healing, infection rate and incidence of subsequent wound breakdown was analysed.

Discussion

Thirteen of 18 patients completed the BTM treatment regime with all these patients achieving complete wound healing at a median time of 13 weeks. One patient had partial treatment with BTM and four patients were withdrawn from the study following BTM application. The rate of infection and re-ulceration were both 15.4%.

Conclusion

This is the first prospective cohort pilot study evaluating the use of BTM for complex diabetic foot wounds. BTM demonstrates potential in healing uninfected, non-ischaemic diabetic foot wounds with exposed deep structures and chronic wounds subject to high shear stress. The re-ulceration and infection rates were relatively low for this high-risk population. BTM may also offer promise as an alternative to free flaps.

Lay Summary

The prevalence of diabetes and its complications, including foot ulcers and wounds, have significantly increased worldwide over the last 40 years. Increasingly patients are admitted to hospital for antibiotics, debridements and subsequent amputations from these wounds. Complex diabetes-associated wounds are those at highest risk of these complications or necessitating more extensive, complex operations such as free flaps. These wounds may have exposed deep structures, be at risk of high shear stress or be chronic non-healing wounds.

Temporisers are a type of material which integrates into the wound and promotes in-growth of tissue, ideal for healing over these difficult to heal areas. Biodegradable Temporising Matrix (BTM) is a synthetic temporising matrix which has demonstrated positive outcomes in facilitating healing in burns and plastics wounds, but its effectiveness in diabetic foot wounds has not yet been proven. This is the first prospective cohort pilot study evaluating the use of BTM for complex diabetic foot wounds. BTM demonstrates potential in healing uninfected, non-ischaemic complex diabetic foot wounds and potentially avoiding more complex operations.

Conductive Biomaterials as Bioactive Wound Dressing for Wound Healing and Skin Tissue Engineering

Conductive biomaterials based on conductive polymers, carbon nanomaterials, or conductive inorganic nanomaterials demonstrate great potential in wound healing and skin tissue engineering, owing to the similar conductivity to human skin, good antioxidant and antibacterial activities, electrically controlled drug delivery, and photothermal effect. However, a review highlights the design and application of conductive biomaterials for wound healing and skin tissue engineering is lacking. In this review, the design and fabrication methods of conductive biomaterials with various structural forms including film, nanofiber, membrane, hydrogel, sponge, foam, and acellular dermal matrix for applications in wound healing and skin tissue engineering and the corresponding mechanism in promoting the healing process were summarized. The approaches that conductive biomaterials realize their great value in healing wounds via three main strategies (electrotherapy, wound dressing, and wound assessment) were reviewed. The application of conductive biomaterials as wound dressing when facing different wounds including acute wound and chronic wound (infected wound and diabetic wound) and for wound monitoring is discussed in detail. The challenges and perspectives in designing and developing multifunctional conductive biomaterials are proposed as well.

Use of confocal microscopy imaging for in vitro assessment of adipose-derived mesenchymal stromal cells seeding on acellular dermal matrices: 3D reconstruction based on collagen autofluorescence

Background

Both mesenchymal stromal cells (MSCs) and acellular dermal matrices (ADMs) represent fascinating therapeutic tools in the wound healing scenario. Strategies aimed at combining these two treatment modalities are currently under investigation. Moreover, scarcity of quantitative, nondestructive techniques for quality assessment of engineered tissues poses great limitations in regenerative medicine and collagen autofluorescence‐based imaging techniques are acquiring great importance in this setting.

Objective

Our goals were to assess the in vitro interactions between ADSCs and ADMs and to analyze extracellular‐matrix production.

Methods

Adipose‐derived MSCs (ADSC) were plated on 8‐mm punch biopsies of a commercially available ADM (Integra®). Conventional histology with hematoxylin‐eosin staining, environmental scanning electron microscopy, and confocal‐laser scanning microscopy were used to obtain imaging of ADSC‐seeded ADMs. Collagen production by ADSCs was quantified by mean fluorescence intensity (MFI), expressed in terms of positive pixels/field, obtained through ImageJ software processing of three‐dimensional projections from confocal scanning images. Control conditions included: fibroblast‐seeded ADM, ADSC‐ and fibroblast‐induced scaffolds, and Integra® alone.

Results

ADSCs were efficiently seeded on Integra® and were perfectly incorporated in the pores of the scaffold. Collagen production was revealed to be significantly higher when ADSCs were seeded on ADM rather than in all other control conditions. Collagen autofluorescence was efficiently used as a surrogate marker of ECM production.

Conclusions

Combined therapies based on MSCs and collagenic ADMs are promising therapeutic options for chronic wounds. Not only ADSCs can be efficiently seeded on ADMs, but ADMs also seem to potentiate their regenerative properties, as highlightable from fluorescence confocal imaging.

Comparison of Skin Substitutes for Acute and Chronic Wound Management

Chronic and acute wounds, such as diabetic foot ulcers and burns, respectively, can be difficult to treat, especially when autologous skin transplantations are unavailable. Skin substitutes can be used as a treatment alternative by providing the structural elements and growth factors necessary for reepithelialization and revascularization from a nonautologous source. As of 2020, there are 76 commercially available skin substitute products; this article provides a review of the relevant literature related to the major categories of skin substitutes available.

Consensus on the application of negative pressure wound therapy of diabetic foot wounds

Because China is becoming an aging society, the incidence of diabetes and diabetic foot have been increasing. Diabetic foot has become one of the main health-related killers due to its high disability and mortality rates. Negative pressure wound therapy (NPWT) is one of the most effective techniques for the treatment of diabetic foot wounds and great progress, both in terms of research and its clinical application, has been made in the last 20 years of its development. However, due to the complex pathogenesis and management of diabetic foot, irregular application of NPWT often leads to complications, such as infection, bleeding and necrosis, that seriously affect its treatment outcomes. In 2020, under the leadership of Burns, Trauma and Tissue Repair Committee of the Cross-Straits Medicine Exchange Association, the writing group for ‘Consensus on the application of negative pressure wound therapy of diabetic foot wounds’ was established with the participation of scholars from the specialized areas of burns, endocrinology, vascular surgery, orthopedics and wound repair. Drawing on evidence-based practice suggested by the latest clinical research, this consensus proposes the best clinical practice guidelines for the application and prognostic evaluation of NPWT for diabetic foot. The consensus aims to support the formation of standardized treatment schemes that clinicians can refer to when treating cases of diabetic foot.

Fast protocol for the processing of split-thickness skin into decellularized human dermal matrix

BACKGROUND

Dermal scaffolds for tissue regeneration are nowadays an effective alternative in not only wound healing surgeries but also breast reconstruction, abdominal wall reconstruction and tendon reinforcement. The present study describes the development of a decellularization protocol applied to human split-thickness skin from cadaveric donors to obtain dermal matrix using an easy and quick procedure.

METHODS

Complete split-thickness donor was decellularized through the combination of hypertonic and enzymatic methods. To evaluate the absence of epidermis and dermal cells, and ensure the integrity of the extracellular matrix (ECM) structure, histological analysis was performed. Residual genetic content and ECM biomolecules (collagen, elastin, and glycosaminoglycan) were quantified and tensile strength was tested to measure the effect of the decellularization technique on the mechanical properties of the tissue.

RESULTS

Biomolecules quantification, residual genetic content (below 50 ng/mg dry tissue) and histological structure assessment showed the efficacy of the decellularization process and the preservation of the ECM. The biomechanical tests confirmed the preservation of native properties in the acellular tissue.

CONCLUSIONS

The acellular dermal matrix obtained from whole split-thickness skin donor with the newly developed decellualrization protocol, maintains the desired biomechanical and structural properties and represents a viable treatment option for patients.

Rabbit as an animal model for the study of biological grafts in pelvic floor dysfunctions

The aims of this study were to evaluate the feasibility of the New Zealand White (NZW) rabbit for studying implanted biomaterials in pelvic reconstructive surgery; and to compare the occurrence of graft-related complications of a commercial polypropylene (PP) mesh and new developed human dermal matrix implanted at vaginal and abdominal level. 20 white female NZW rabbits were randomized into two groups, experimental group (human acellular dermal matrices-hADM-graft) and control group (commercial PP graft). In each animal, grafts were surgically implanted subcutaneously in the abdominal wall and in the vaginal submucosa layer for 180 days. The graft segments were then removed and the surgical and clinical results were analyzed. The main surgical challenges during graft implantation were: (a) an adequate vaginal exposure while maintaining the integrity of the vaginal mucosa layer; (b) to keep aseptic conditions; (c) to locate and dissect the breast vein abdominal surgery; and (d) to withdraw blood samples from the ear artery. The most abnormal findings during the explant surgery were found in the PP group (33% of vaginal mesh extrusion) in comparison with the hADM group (0% of vaginal graft extrusion), p = 0.015. Interestingly, macroscopic observation showed that the integration of the vaginal grafts was more common in the hADM group (40%) than in the PP group, in which the vaginal mesh was identified in 100% of the animals (p = 0.014). The NZW rabbit is a good model for assessing materials to be used as grafts for pelvic reconstructive surgery and vaginal surgery. Animals are easily managed during the procedures, including surgical intervention and vaginal mucosa approach. Additionally, hADM is associated with fewer clinical complications, as well as better macroscopic tissue integration, compared to PP mesh.

Chronic Diabetic Wounds and Their Treatment with Skin Substitutes

With the global prevalence of type 2 diabetes mellitus steeply rising, instances of chronic, hard-healing, or non-healing diabetic wounds and ulcers are predicted to increase. The growing understanding of healing and regenerative mechanisms has elucidated critical regulators of this process, including key cellular and humoral components. Despite this, the management and successful treatment of diabetic wounds represents a significant therapeutic challenge. To this end, the development of novel therapies and biological dressings has gained increased interest. Here we review key differences between normal and chronic non-healing diabetic wounds, and elaborate on recent advances in wound healing treatments with a particular focus on biological dressings and their effect on key wound healing pathways.

Adipose-Derived Stromal Cell-Sheets Sandwiched, Book-Shaped Acellular Dermal Matrix Capable of Sustained Release of Basic Fibroblast Growth Factor Promote Diabetic Wound Healing

The management of diabetic wounds is a therapeutic challenge in clinical settings. Current tissue engineering strategies for diabetic wound healing are insufficient, owing to the lack of an appropriate scaffold that can load a large number of stem cells and induce the interaction of stem cells to form granulation tissue. Herein we fabricated a book-shaped decellularized dermal matrix (BDDM), which shows a high resemblance to native dermal tissue in terms of its histology, microstructure, and ingredients, is non-cytotoxic and low-immunogenic, and allows adipose-derived stromal cell (ASC) attachment and proliferation. Then, a collagen-binding domain (CBD) capable of binding collagen was fused into basic fibroblast growth factor (bFGF) to synthetize a recombinant growth factor (termed as CBD-bFGF). After that, CBD-bFGF was tethered onto the collagen fibers of BDDM to improve its endothelial inducibility. Finally, a functional scaffold (CBD-bFGF/BDDM) was fabricated. In vitro and in vivo experiments demonstrated that CBD-bFGF/BDDM can release tethered bFGF with a sustained release profile, steadily inducing the interaction of stem cells down to endothelial differentiation. ASCs were cultured to form a cell sheet and then sandwiched by CBD-bFGF/BDDM, thus enlarging the number of stem cells loaded into the scaffold. Using a rat model, the ASC sheets sandwiched with CBD-bFGF/BDDM (ASCs/CBD-bFGF/BDDM) were capable of enhancing the formation of granulation tissue, promoting angiogenesis, and facilitating collagen deposition and remodeling. Therefore, the findings of this study demonstrate that ASCs/CBD-bFGF/BDDM could be applicable for diabetic wound healing.

Outcomes and Predictors of Wound Healing among Patients with Complex Diabetic Foot Wounds Treated with a Dermal Regeneration Template (Integra)

BACKGROUND

The utility of dermal regeneration templates for treating high-risk diabetic foot wounds is unclear. The authors report wound healing and major amputation outcomes among a cohort of diabetic patients with complex diabetic foot wounds treated in a multidisciplinary setting.

METHODS

All patients with complex diabetic foot wounds treated with a dermal regeneration template (March of 2013 to February of 2019) were captured in a prospective institutional database. Wound severity was classified according to the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system to determine limb salvage prognosis at baseline. Wound healing and major amputation rates were reported using Kaplan-Meier analyses. A stepwise Cox proportional hazards model was used to identify independent characteristics associated with wound healing.

RESULTS

Eighty-five patients with 107 complex diabetic foot wounds were treated (mean age, 61.2 ± 3.3 years; 63.5 percent male and 61.2 percent African American). Most diabetic foot wounds were high-risk (wound, ischemia, and foot infection stage 3 or 4, 93.5 percent), corresponding to a predicted 25 to 50 percent risk of major amputation at 1 year. Dermal regeneration template use resulted in successful wound granulation in 66.7 percent of cases, with a mean time to complete wound healing of 198 ± 18 days. Twelve- and 18-month wound healing rates were 79.0 ± 5.0 percent and 93.0 ± 3.3 percent, respectively. Major amputation was required in 11.2 percent of patients. Independent predictors of poor wound healing included lack of bone involvement, higher WIfI stage, and prior dermal regeneration template failure.

CONCLUSION

Application of a dermal regeneration template to complex diabetic foot wounds at high risk for major amputation results in good wound healing and excellent limb salvage outcomes among diabetic patients treated in a multidisciplinary setting.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

A Novel Composite Hydrogel Composed of Formic Acid-Decellularized Pepsin-Soluble Extracellular Matrix Hydrogel and Sacchachitin Hydrogel as Wound Dressing to Synergistically Accelerate Diabetic Wound Healing

Extracellular matrix (ECM) hydrogel can create a favorable regenerative microenvironment and act as a promising dressing for accelerating the healing of diabetic wound. In this study, a simple and effective decellularization technique was developed and optimized to obtain acellular extracellular matrix (aECM) from porcine skin. It was found that decellularization at 30% formic acid for 72 h effectively decellularized porcine skin while retaining >75% collagen and ~37% GAG in the aECM with no presence of nuclei of cellular remnants. aECM hydrogel was fabricated by digesting aECM with pepsin in various acidic solutions (0.1 N HCl, glycolic acid (GA) and 2-pyrrolidone-5-carboxylic acid (PCA)) and then treated with a pH-controlled neutralization and temperature-controlled gelation procedure. Based on physical characterizations, including SDS-PAGE, rheological analysis and SEM analysis, aECM_HCl hydrogels fabricated at 25 mg/mL in 0.1 N HCl were selected. Four polymeric ECM-mimic hydrogels, including sacchachitin (SC), hyaluronic acid (HA) and chitosan (CS) and three composite hydrogels of combining SC either with aECM_HCl,25 (aECM_HCl/SC), HA (HA/SC) or CS (SC/CS) were prepared and evaluated for WS-1 cell viability and wound-healing effectiveness. Cell viability study confirmed that no hydrogel dressings possessed any toxicity at all concentrations examined and ECM_HCl, HA and ECM_HCl/SC at higher concentrations (>0.05%) induced statistically significant proliferation. Diabetic wound healing study and histological examinations revealed that ECM_HCl/SC hydrogel was observed to synergistically accelerate wound healing and ultimately stimulated the growth of hair follicles and sweat glands in the healing wound indicating the wound had healed as functional tissues. The results support the great potential of this newly produced ECM_HCl/SC composite hydrogel for healing and regeneration of diabetic wounds.

An observational pilot study using a purified reconstituted bilayer matrix to treat non-healing diabetic foot ulcers

Diabetic foot ulcers (DFUs) have significant clinical impact and carry a substantial economic burden. Patients with DFUs that are refractory to standard wound care are at risk for major complications, including infection and amputation and have an increased risk of mortality. This study evaluated the safety and preliminary efficacy of a novel decellularised purified reconstituted bilayer matrix (PRBM) in treating DFUs. Ten diabetic patients with refractory wounds that failed to heal after at least 4 weeks of standard wound care were studied in this Institutional Review Board approved trial. Ten consecutive wounds were treated weekly with the PRBM for up to 12 weeks. At each weekly visit, the wound was evaluated, photographed, and cleaned, followed by application of new graft if not completely epithelialised. Assessment included measurement of the wound area and inspection of the wound site for signs of complications. The primary outcome measure was wound closure, as adjudicated by independent reviewers. Secondary outcomes included assessment of overall adverse events, time to closure, percent area reduction, and the cost of product(s) used. Nine of 10 patients achieved complete wound closure within 4 weeks, and 1 did not heal completely within 12 weeks. The mean time to heal was 2.7 weeks. The mean wound area reduction at 12 weeks was 99%. No adverse events nor wound complications were observed. These early clinical findings suggest that the PRBM may be an effective tool in the treatment of diabetic foot ulcers.

Use of Nevelia Dermal-Epidermal Regenerative Template in the Management of Ischemic Diabetic Foot Postsurgical Wounds

The purpose of this cross-sectional study is evaluate the effectiveness of a dermal-epidermal substitute (DES) composed of 3-dimensional porous matrix of type 1, purified, stabilized, bovin-origin collagen (Nevelia, SYMATESE, Chaponost, France) without a subsequent skin graft in the treatment ischemic postsurgical diabetic foot ulcers. This study group was composed of a sample of consecutive diabetic patients with critical limb ischemia and postsurgical wounds. All patients received a preset limb salvage protocol including the application of the DES, but none received a skin graft. Patients were closely followed until wound healing or different outcome. The outcome measures were healing, nonhealing, major amputation, and death evaluated at 1 and 2 years of follow-up. Forty-one patients were included. The average postsurgical wound area was 69.6 ± 50 cm². Twenty-one patients (51%) healed; 10 patients (24%) did not heal after 1 year of follow-up; however, all of them achieved a mean ulcer size reduction >50%; 7 patients (17%) were amputees; 3 patients (7.3%) died. In a later follow-up (2 years), wounds in 8 additional patients healed. Successful revascularization was an independent predictor of healing (hazard ratio = 5.1, 95% confidence interval [CI] = 2.5-14-9; P = .0001), the postsurgical ulcer size (>50 cm²) was an independent predictor of nonhealing (hazard ratio = 6.2, 95% CI = 2.1-38.4; P = .0001) while recurrence of critical limb ischemia was an independent predictor of major amputation (odds ratio = 3.4, 95% CI = 1.1-4.5; P = .002). The DES composed of type 1 bovin-origin collagen is useful in the treatment of large postsurgical diabetic foot ulcers, even when the skin graft is not a suitable therapeutic option.

The Efficacy and Safety of Acellular Matrix Therapy for Diabetic Foot Ulcers: A Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Acellular matrix (AM) therapy has shown promise in the treatment of diabetic foot ulcers (DFUs) in several studies. The clinical effects of AM therapy were not well established. Therefore, we conducted a meta-analysis of randomized clinical trials (RCTs) to examine the efficacy and safety of AM therapy for patients with DFUs.

METHODS

A literature search of 5 databases was performed to identify RCTs comparing AM therapy to standard therapy (ST) in patients with DFUs. The primary outcome was the complete healing rate and the secondary outcomes mainly included time to complete healing and adverse events.

RESULTS

Nine RCTs involving 897 patients were included. Compared with ST group, patients allocated to AM group had a higher complete healing rate both at 12 weeks (risk ratio (RR) = 1.73, 95% confidence interval (CI): 1.31 to 2.30) and 16 weeks (RR = 1.56, 95% CI: 1.28 to 1.91), a shorter time to complete healing (mean difference (MD) = -2.41; 95% CI: -3.49 to -1.32), and fewer adverse events (RR = 0.64, 95% CI: 0.44 to 0.93).

CONCLUSION

The present study suggests that AM therapy as an adjuvant treatment could further promote the healing of full-thickness, noninfected, and nonischemia DFUs. AM therapy also has a safety profile. More large well-designed randomized clinical trials with long follow-up duration are needed to further explore the efficacy and safety of AM therapy for DFUs.

Usefulness of Allogenic Acellular Dermal Matrix for Prevention of Scalp Depression after Burr Hole Trephination

Objective

Burr hole trephination is a common treatment for chronic subdural hematoma, intracranial hematoma, and intraventricular hematoma due to its effective drainage of hematoma, minimal invasiveness and short operation time. However, cosmetic complications such as scalp depression can occur. The aim of this study was to evaluate the usefulness of an allogenic acellular dermal matrix (ADM) to prevent scalp depression at the burr hole site.

Methods

A retrospective analysis was performed with 75 cases in 66 patients who were treated with burr hole trephination from January 2018 to December 2019. These cases divided into 2 groups; based on the method used to cover the burr hole site: Gelfoam packing only (GPO) and ADM. The degree of the scalp depression was measured from the more recent follow-up brain computed tomography scan.

Results

There was a significant difference in the degree of scalp depression between GPO and ADM groups (p=0.003). No significant correlation between patient's age and the degree of scalp depression (GPO: p=0.419, ADM: p=0.790). There were no wound infection complication in either group.

Conclusion

ADM is a suitable material to prevent scalp depression after burr hole trephination.

Health economics for treatment of diabetic foot ulcers: a cost-effectiveness analysis of eight skin substitutes

Aim:

Skin substitutes are frequently used to treat chronic diabetic foot ulcers (DFU), and many different options are available. While the clinical efficacy of many products has been evaluated, a comprehensive cost-effectiveness analysis comparing the most popular skin substitutes and using the most recent cost data has been lacking.

Methods:

This study compared eight skin substitutes using published efficacy rates combined with the Centers for Medicare and Medicaid Services (CMS) 2018 cost data. The study criteria resulted in the inclusion of seven studies that described efficacy rates for treatment of DFUs using the skin substitutes.

Results:

The results revealed wide discrepancies between these skin substitutes for the costs of treatments and healing rates in hospital outpatient departments and physician office settings. Healing rates for 12 and 16 weeks ranged from 28% to 68%, while the average cost for treating one DFU varied from $2001 to $14,507 and $1207 to $8791 in the hospital outpatient department and physician's office setting, respectively. The estimated patient share of costs for treating a single DFU ranged from $400 to $2901 and $241 to $1758 in the hospital outpatient department and physician's office setting, respectively. Most importantly, the estimated number of wounds healed out of 100 DFUs per $1000 expenditure with each patient ranged from 3.9–26.5 DFUs in the hospital outpatient department, and 4.3–36.4 DFUs in the physicians' office setting.

Conclusions:

This study revealed that the costs of a skin substitute itself did not necessarily correlate with its healing efficacy. These results provide a comprehensive cost-effectiveness analysis to enable integrated health-care systems, health professionals and reimbursement payers to make informed value decisions when treating DFUs.

Slow to heel: a literature review on the management of diabetic calcaneal ulceration

The diabetic heel ulcer (DHU) represents a reconstructive challenge to clinicians and the multidisciplinary team alike. It is traditionally viewed as a condition that is inherently difficult to treat due to the intrinsic anatomical vulnerabilities of the heel. In addition to this, several factors are associated with poorer end outcomes - namely, that of major amputation. These include peripheral vascular disease, infection/osteomyelitis and the size of the ulcer itself. In light of the significant morbidity, economic burden and mortality seen in this cohort of patients, this review aims to explore current treatment modalities that have been undertaken. Literature in this field has mostly been confined to a handful of small case studies, some of which reflect novel, multimodal approaches, and promising results. Management with osteotomy, flap reconstruction and acellular dermal matrices, amongst other options, is covered within this review.

Update on management of diabetic foot ulcers

Diabetic foot ulcers (DFUs) are a serious complication of diabetes that results in significant morbidity and mortality. Mortality rates associated with the development of a DFU are estimated to be 5% in the first 12 months, and 5-year morality rates have been estimated at 42%. The standard practices in DFU management include surgical debridement, dressings to facilitate a moist wound environment and exudate control, wound off-loading, vascular assessment, and infection and glycemic control. These practices are best coordinated by a multidisciplinary diabetic foot wound clinic. Even with this comprehensive approach, there is still room for improvement in DFU outcomes. Several adjuvant therapies have been studied to reduce DFU healing times and amputation rates. We reviewed the rationale and guidelines for current standard of care practices and reviewed the evidence for the efficacy of adjuvant agents. The adjuvant therapies reviewed include the following categories: nonsurgical debridement agents, dressings and topical agents, oxygen therapies, negative pressure wound therapy, acellular bioproducts, human growth factors, energy-based therapies, and systemic therapies. Many of these agents have been found to be beneficial in improving wound healing rates, although a large proportion of the data are small, randomized controlled trials with high risks of bias.