Changes in miroRNA-103 expression in wound margin tissue are related to wound healing of diabetes foot ulcers

To investigate the relationship between small noncoding microRNA-103 (miR-103) and wound healing of diabetic foot ulcers (DFU) and the underlying molecular mechanism, forty type 2 diabetes mellitus with DFU (DFU group), and 20 patients with a chronic skin ulcer of lower limbs and normal glucose tolerance (SUC group) were included. Quantitative real-time PCR method was used to determine miR-103 expression levels in the wound margin tissue of subjects, and to analyse the relationship between the expression of miR-103 and DFU wound healing. In vitro experiments were also performed to understand the effect of miR-103 on the high glucose-induced injury of normal human dermal fibroblasts (NHDFs) cells. The results showed that the miR-103 expression level in the DFU group was significantly higher than that in the SUC group [5.81 (2.25–9.36) vs 2.08 (1.15–5.72)] (P < 0.05). The expression level of miR-103 in the wound margin tissue of DFU was negatively correlated with the healing rate of foot ulcers after four weeks (P = 0.037). In vitro experiments revealed that miR-103 could inhibit the proliferation and migration of NHDF cells and promote the apoptosis of NHDF cells by targeted regulation of regulator of calcineurin 1 (RCAN1) gene expression in a high glucose environment. Down-regulation of miR-103 could alleviate high glucose-induced NHDF cell injury by promoting RCAN1 expression. Therefore, the increased expression of miR-103 is involved in the functional damage of NHDF cells induced by high-glucose conditions, which is related to poor wound healing of DFU. These research findings will provide potential targets for the diagnosis and treatment of chronic skin wounds in diabetes.     

Changes in the extracellular matrix surrounding human chronic wounds revealed by 2‐photon imaging

Chronic wounds are a growing problem worldwide with no effective therapeutic treatments available. Our objective was to understand the composition of the dermal tissue surrounding venous leg ulcers and diabetic foot ulcers (DFU). We used novel 2‐photon imaging techniques alongside classical histology to examine biopsies from the edges of two common types of chronic wound, venous leg ulcers and DFU. Compared to normal intact skin, we found that collagen levels are significantly reduced throughout the dermis of venous leg ulcer biopsies and DFU, with a reduction in both fibril thickness and abundance. Both wound types showed a significant reduction in elastin in the upper dermis, but in DFU, the loss was throughout the dermis. Loss of extracellular matrix correlated with high levels of CD68‐ and CD18‐positive leukocytes. 2‐photon imaging of the extracellular matrix in the intact tissue surrounding a chronic wound with a hand‐held device may provide a useful clinical indicator on the healing progression or deterioration of these wounds.     

Extracellular matrix/stromal vascular fraction gel conditioned medium accelerates wound healing in a murine model

Conditioned medium (CM) is a new treatment modality in regenerative medicine and has shown a successful outcome in wound healing. We recently introduced extracellular matrix/stromal vascular fraction gel (ECM/SVF‐gel), an adipose‐derived stem cell and adipose native extracellular matrix‐enriched product for cytotherapy. This study aimed to evaluate the effect of CM from ECM/SVF‐gel (Gel‐CM) on wound healing compared with the conventional CM from adipose tissue (Adi‐CM) and stem cell (SVF‐CM). In vitro wound healing effect of three CMs on keratinocytes and fibroblasts was evaluated in terms of proliferation property, migratory property, and extracellular matrix production. In vivo, two full‐thickness wounds were created on the back of each mice. The wounds were randomly divided to receive Gel‐CM, Adi‐CM, SVF‐CM, and PBS injection. Histologic observations and collagen content of wound skin were made. Growth factors concentration in three CMs was further quantified. In vitro, Gel‐CM promoted the proliferation and migration of keratinocytes and fibroblasts and enhanced collagen I synthesis in fibroblasts compared to Adi‐CM and SVF‐CM. In vivo, wound closure was faster, and dermal and epidermal regeneration was improved in the Gel‐CM‐treated mice compared to that in Adi‐CM and SVF‐CM‐treated mice. Moreover, The growth factors concentration (i.e., vascular endothelial growth factor, basic fibroblast growth factor, hepatocyte growth factor, and transforming growth factor‐β) in Gel‐CM were significantly higher than those in Adi‐CM and SVF‐CM. Gel‐CM generated under serum free conditions significantly enhanced wound healing effect compared to Adi‐CM and SVF‐CM by accelerating cell proliferation, migration, and production of ECM. This improved trophic effect may be attributed to the higher growth factors concentration in Gel‐CM. Gel‐CM shows potential as a novel and promising alternative to skin wound healing treatment. But limitations include the safety and immunogenicity studies of Gel‐CM still remain to be clearly clarified and more data on mechanism study are needed.     

High‐dose folic acid and its effect on early stage diabetic foot ulcer wound healing

High‐dose folic acid (HDFA; vitamin B9)—5 mg, given daily, has not been evaluated as a treatment to improve early stage‐diabetic foot ulcer (ES‐DFU) wound healing. However, HDFA has been demonstrated to correct: (a) endothelial dysfunction and decreased nitric oxide (NO) bioavailability, associated with type‐2 diabetes mellitus (T2DM); and (b) hyperhomocysteinemia (HHcy) that may promote impaired DFU‐wound healing. Measures of wound area (cm²) reduction (wound closure; WC), over a 4‐week period (4 W‐WC), greater than 50% of the wound area, have been reported as a robust indicator of the potential for DFU‐wound healing. By using this model, we examined the effectiveness of a wound treatment in promoting progressive healing and complete wound closure for the chronic, nonhealing DFU‐wound. To investigate this possible relationship between HDFA and ES‐DFU wound healing, a retrospective cohort study of medical records, between November 2018 and April 2019, was performed for Veterans with T2DM and ES‐DFUs following treatment with HDFA. During the study period 29 (n = 29) Veterans with ES‐DFU wounds who received HDFA treatment were identified. Medical record reviews of this retrospective cohort of ES‐DFU Veterans receiving HDFA report 90% (26/29) experiencing complete DFU‐wound closure during the study period. Of the 29 Veterans with ES‐DFUs receiving HDFA, the medical records of nine (30%), with healed wounds, provided documentation suitable for 4 W‐WC, pre‐ and post‐HDFA treatment study comparisons. This study documents significant (P < .05) improvements comparing 4 W‐WC values for standard treatment for Veterans with poorly progressing, worsening or stagnating ES‐DFU‐wounds to those for the same subjects following HDFA treatment. These observations suggest that chronic ES‐DFUs treated with HDFA may experience significantly improved wound closure and complete healing (re‐epithelialization) when compared with standard treatments without HDFA. With validation from RCTs, HDFA may be established as an effective treatment to promote wound healing and closure for nonhealing ES‐DFUs.     

Chronic wounds – is cellular ‘reception’ at fault? Examining integrins and intracellular signalling

As with all physiologic processes, chronic wounds are associated with unique intracellular and cellular/extracellular matrix (ECM) receptor types and signalling messages. These cellular receptors mediate responses of the epidermis to provisional wound matrix and change in form and number in cases of impaired wound healing. Integrins are the major cell‐surface receptors for cell adhesion and migration and epidermal keratinocytes express several integrins that bind ECM ligands in provisional wound ECM. Integrin receptors and more particularly integrin clusters and focal adhesion points appear to influence epidermal and dermal cell matrix interactions, cell motility, cell phenotype and ultimate healing trajectory. In chronic wounds, a variety of changes in receptors have been identified: decreased integrin α5β1 receptors affect the integration of fibronectin and subsequent keratinocyte migration; integrin αvβ6 stimulate transforming growth factor (TGF)‐β and may increase the susceptibility to ulceration and fibrosis; however, TGF‐β signal receptors have been found to be dysfunctional in many chronic wounds; additionally receptor interactions result in increased senescent cells including fibroblasts, myofibroblasts and even keratinocytes – this produces a degradative ECM and wound bed and corrosive chronic wound fluid. The activation or inhibition of integrin receptors by various agents may provide an excellent means of influencing wound healing. This process offers an earlier intervention into the wound healing cascade promoting intrinsic healing and elaboration of growth factors and ECM proteins, which may be more cost effective than the traditional attempts at extrinsic addition of these agents.     

Agent-based model of inflammation and wound healing: insights into diabetic foot ulcer pathology and the role of transforming growth factor-β1

Inflammation and wound healing are inextricably linked and complex processes, and are deranged in the setting of chronic, nonhealing diabetic foot ulcers (DFU). An ideal therapy for DFU should both suppress excessive inflammation while enhancing healing. We reasoned that biological simulation would clarify mechanisms and help refine therapeutic approaches to DFU. We developed an agent-based model (ABM) capable of reproducing qualitatively much of the literature data on skin wound healing, including changes in relevant cell populations (macrophages, neutrophils, fibroblasts) and their key effector cytokines (tumor necrosis factor-alpha [TNF], interleukin [IL]-1beta, IL-10, and transforming growth factor [TGF]-beta1). In this simulation, a normal healing response results in tissue damage that first increases (due to wound-induced inflammation) and then decreases as the collagen levels increase. Studies by others suggest that diabetes and DFU are characterized by elevated TNF and reduced TGF-beta1, although which of these changes is a cause and which one is an effect is unclear. Accordingly, we simulated the genesis of DFU in two ways, either by (1) increasing the rate of TNF production fourfold or (2) by decreasing the rate of TGF-beta1 production 67% based on prior literature. Both manipulations resulted in increased inflammation (elevated neutrophils, TNF, and tissue damage) and delayed healing (reduced TGF-beta1 and collagen). Our ABM reproduced the therapeutic effect of platelet-derived growth factor/platelet releasate treatment as well as DFU debridement. We next simulated the expected effect of administering (1) a neutralizing anti-TNF antibody, (2) an agent that would increase the activation of endogenous latent TGF-beta1, or (3) latent TGF-beta1 (which has a longer half-life than active TGF-beta1), and found that these therapies would have similar effects regardless of the initial assumption of the derangement that underlies DFU (elevated TNF vs. reduced TGF-beta1). In silico methods may elucidate mechanisms of and suggest therapies for aberrant skin healing.     

Effect of Panax ginseng extract on the activity of diabetic fibroblasts in vitro

Numerous studies have demonstrated the various medicinal properties of Panax ginseng, including angiogenic, immuno‐stimulating, antimicrobial, and anti‐inflammatory activities, which can be helpful in chronic wound healing. However, a direct role for P. ginseng in chronic wound healing has not been demonstrated. The present study was designed to evaluate the effects of P. ginseng extract on diabetic fibroblasts in vitro. Human diabetic fibroblasts were cultured in the presence of Ginsenoside Rb1 (G‐Rb1), the active component in P. ginseng (10 ng/mL), and untreated diabetic fibroblasts were used as controls. Cell proliferation, collagen synthesis, the production of various growth factors (basic fibroblast growth factor [bFGF]; vascular endothelial growth factor [VEGF]; and transforming growth factor‐β1 [TGF‐β1]), and the synthesis of matrix metalloproteinase 1 (MMP‐1) and tissue inhibitor of metalloproteinases 1 (TIMP‐1) were compared using enzyme‐linked immunosorbent assay and immunofluorescence staining. Compared with the control group, G‐Rb1‐treated fibroblasts showed significantly (P < 0.05) higher levels of cell proliferation, collagen synthesis, VEGF, TGF‐β1, and TIMP‐1. However, no significant differences in bFGF and MMP‐1 levels were observed between the two groups. These results suggest that P. ginseng treatment may stimulate the wound‐healing activity of diabetic fibroblasts in vitro.     

The role of endogenous and exogenous enzymes in chronic wounds: A focus on the implications of aberrant levels of both host and bacterial proteases in wound healing

Cutaneous wound healing is orchestrated by a number of physiological pathways that ultimately lead to reformation of skin integrity and the production of functional scar tissue. The remodeling of a wound is significantly affected by matrix metalloproteinases (MMPs), which act to control the degradation of the extracellular matrix (ECM). Regulation of MMPs is imperative for wound healing as excessive levels of MMPs can lead to disproportionate destruction of the wound ECM compared to ECM deposition. In addition to human MMPs, bacterial proteases have been found to be influential in tissue breakdown and, as such, have a role to play in the healing of infected wounds. For example, the zinc‐metalloproteinase, elastase, produced by Pseudomonas aeruginosa, induces degradation of fibroblast proteins and proteoglycans in chronic wounds and has also been shown to degrade host immune cell mediators. Microbial extracellular enzymes have also been shown to degrade human wound fluid and inhibit fibroblast cell growth. It is now being acknowledged that host and bacterial MMPs may act synergistically to cause tissue breakdown within the wound bed. Several studies have suggested that bacterial‐derived secreted proteases may act to up‐regulate the levels of MMPs produced by the host cells. Together, these findings indicate that bacterial phenotype in terms of protease producing potential of bacteria should be taken into consideration during diagnostic and clinical intervention of infected wound management. Furthermore, both host MMPs and those derived from infecting bacteria need to be targeted in order to increase the healing capacity of the injured tissue. The aim of this review is to investigate the evidence suggestive of a relationship between unregulated levels of both host and bacterial proteases and delayed wound healing.     

Human acellular dermal wound matrix: evidence and experience

A chronic wound fails to complete an orderly and timely reparative process and places patients at increased risk for wound complications that negatively impact quality of life and require greater health care expenditure. The role of extracellular matrix (ECM) is critical in normal and chronic wound repair. Not only is ECM the largest component of the dermal skin layer, but also ECM proteins provide structure and cell signalling that are necessary for successful tissue repair. Chronic wounds are characterised by their inflammatory and proteolytic environment, which degrades the ECM. Human acellular dermal matrices, which provide an ECM scaffold, therefore, are being used to treat chronic wounds. The ideal human acellular dermal wound matrix (HADWM) would support regenerative healing, providing a structure that could be repopulated by the body's cells. Experienced wound care investigators and clinicians discussed the function of ECM, the evidence related to a specific HADWM (Graftjacket^® regenerative tissue matrix, Wright Medical Technology, Inc., licensed by KCI USA, Inc., San Antonio, TX), and their clinical experience with this scaffold. This article distills these discussions into an evidence‐based and practical overview for treating chronic lower extremity wounds with this HADWM.     

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.     

Efficacy of intralesional recombinant human epidermal growth factor in diabetic foot ulcers in Mexican patients: A randomized double‐blinded controlled trial

The healing process in diabetic foot ulcer (DFU) is hindered by factors such as chronic inflammation, defects in fibroblast function, poor angiogenesis, and lack of cell migration. Recombinant human epidermal growth factor (rhEGF) has been shown to enhance extracellular matrix formation, cellular proliferation, and angiogenesis. Therefore, intralesional application of rhEGF in DFU could accelerate wound healing. Our objective was to determine the efficacy and safety of rhEGF in patients with DFU. A randomized, double‐blinded, placebo‐controlled study was conducted comparing a thrice‐per‐week intralesional application of rhEGF (75 μg) or placebo in patients with DFU for 8 weeks. The number of completely healed ulcers, size, and wound bed characteristics were evaluated to determine the efficacy of rhEGF. Adverse events were recorded and analyzed to establish its safety. A total of 34 patients were recruited for the study. After three dropouts, we were able to follow and analyze 16 patients in the placebo group and 15 patients in the rhEGF study to the end of the trial. Baseline testing showed that both groups were similar. Compared to the placebo group, more ulcers achieved complete healing in the rhEGF group (rhEGF, n = 4; placebo, n = 0; p = 0.033); ulcers in the rhEGF group decreased in area size (12.5 cm2 [rhEGF] vs. 5.2 cm2 [placebo]; p = 0.049); and more epithelial islands in the wound bed were present (28% vs. 3%; p = 0.025). Mild transitory dizziness was the only side effect that was more frequently noted in the rhEGF group. Our results showed that in patients with DFU who received standard care, intralesional rhEGF application resulted in complete healing in more patients, promoted the epithelialization of the wound bed, and significantly reduced the area of the DFU treated. Therefore, rhEGF resulted in better outcomes for patients suffering from DFU.     

NPWT促进糖尿病足溃疡创面愈合分子机制的初步研究

目的通过检测与创面愈合进程相关的组织基因表达,探讨采用负压创面治疗(nagetive pressure wound therapy,NPWT),促进糖尿病足溃疡(diabetic foot ulcer, DFU)愈合的作用机制。方法将纳入的50例DFU患者随机分成NPWT组(25例)和对照组(25例)。对照组接受局部湿敷治疗。两组患者治疗前后10 d均取创面肉芽行组织活检,利用RT-PCR检测转移生长因子-β1(transforminggrowth factor beta 1, TGF-β1)、血管内皮生长因子(vascular endothelial growth factor, VEGF)、肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)、白介素-1β(interleukin-1β, IL-1β)、基质金属蛋白酶-1(matrix metalloproteinase-1, MMP-1)、基质金属蛋白酶-9(matrixmetalloproteinase-9, MMP-9)和基质金属蛋白酶抑制剂-1(tissue inhibitor of metalloproteinase-1, TIMP-1)的mRNA表达,并进行对比分析。结果治疗后10 d,NPWT组患者创面肉芽组织中VEGF、TGF-β1和TIMP-1 mRNA的表达较治疗前显著增加,IL-1β、TNF-α、MMP-1和MMP-9 mRNA的表达显著下降(P<0.05);而对照组上述各项指标的mRNA表达,治疗前后均无显著变化(P>0.05)。结论 NPWT可能通过影响生长因子、炎症细胞因子和基质金属蛋白酶的表达来促进DFU愈合。     

Integrative analysis of miRNA and mRNA paired expression profiling of primary fibroblast derived from diabetic foot ulcers reveals multiple impaired cellular functions

Diabetic foot ulcers (DFUs) are one of the major complications of diabetes. Its molecular pathology remains poorly understood, impeding the development of effective treatments. Although it has been established that multiple cell types, including fibroblasts, keratinocytes, macrophages, and endothelial cells, all contribute to inhibition of healing, less is known regarding contributions of individual cell type. Thus, we generated primary fibroblasts from nonhealing DFUs and evaluated their cellular and molecular properties in comparison to nondiabetic foot fibroblasts (NFFs). Specifically, we analyzed both micro‐RNA and mRNA expression profiles of primary DFU fibroblasts. Paired genomic analyses identified a total of 331 reciprocal miRNA–mRNA pairs including 21 miRNAs (FC > 2.0) along with 239 predicted target genes (FC > 1.5) that are significantly and differentially expressed. Of these, we focused on three miRNAs (miR‐21‐5p, miR‐34a‐5p, miR‐145‐5p) that were induced in DFU fibroblasts as most differentially regulated. The involvement of these microRNAs in wound healing was investigated by testing the expression of their downstream targets as well as by quantifying cellular behaviors in prospectively collected and generated cell lines from 15 patients (seven DFUF and eight NFF samples). We found large number of downstream targets of miR‐21‐5p, miR‐34a‐5p, miR‐145‐5p to be coordinately regulated in mRNA profiles, which was confirmed by quantitative real‐time PCR. Pathway analysis on paired miRNA–mRNA profiles predicted inhibition of cell movement and cell proliferation, as well as activation of cell differentiation and senescence in DFU fibroblasts, which was confirmed by cellular assays. We concluded that induction of miR‐21‐5p, miR‐34a‐5p, miR‐145‐5p in DFU dermal fibroblasts plays an important role in impairing multiple cellular functions, thus contributing to overall inhibition of healing in DFUs.     

Non-coding RNAs: Role in diabetic foot and wound healing

Diabetic foot ulcer (DFU) and poor wound healing are chronic complications in patients with diabetes. The increasing incidence of DFU has resulted in huge pressure worldwide. Diagnosing and treating this condition are therefore of great importance to control morbidity and improve prognosis. Finding new markers with potential diagnostic and therapeutic utility in DFU has gathered increasing interest. Wound healing is a process divided into three stages: Inflammation, proliferation, and regeneration. Non-coding RNAs (ncRNAs), which are small protected molecules transcribed from the genome without protein translation function, have emerged as important regulators of diabetes complications. The deregulation of ncRNAs may be linked to accelerated DFU development and delayed wound healing. Moreover, ncRNAs can be used for therapeutic purposes in diabetic wound healing. Herein, we summarize the role of microRNAs, long ncRNAs, and circular RNAs in diverse stages of DFU wound healing and their potential use as novel therapeutic targets.     

Mesenchymal stem cells' interaction with skin: Wound‐healing effect on fibroblast cells and skin tissue

Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the ability to secrete growth factors. Because wound healing is associated with fibroblast cells and extracellular matrix (ECM) in the dermis and epidermis, we used fibroblast cells to resolve the question of whether or not MSCs regulate wound healing in vitro via a regenerative function. Using a cell proliferation assay, we demonstrated that conditioned media (CM) obtained from MSCs significantly enhanced the cell survival ability of fibroblast cells. Moreover, by measurement of mRNA and protein, we observed that CM also promoted the production or secretion of collagen, elastin, and fibronectin. To better understand the effects of ECM‐related wound healing, we measured the level of collagen‐degradative enzyme (matrix metalloprotease‐1), and observed that CM suppressed matrix metalloprotease‐1 expression. For the determination of oxidative stress, which has an influence on wound healing, we performed the superoxide dismutase and glutathione peroxidase assays; our results suggested that CM inhibited the oxidative stress of fibroblast cells. In order to widely investigate the wound‐healing effects of MSCs, we performed in vivo experiments, and observed that MSCs stimulated wound healing. In summary, the results of this study suggest that MSCs inhibit the loss of fibroblast cells and ECM, and accumulation of oxidative stress. We found that MSCs stimulate wound healing in vitro and in vivo, suggesting that MSCs have the potential to enhance wound healing.     

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.     

Nutritional supplementation on wound healing in diabetic foot: What is known and what is new?

Non-healing diabetic foot ulcers (DFU) are the most notable and striking complications of diabetes mellitus. More than 25% of nonhealing DFU can ultimately lead to amputation of the lower extremity within 6-18 mo after the first manifestation of the wound. Although wound healing is complex, nutritional status is crucial in soft tissue repair. Malnutrition is highly prevalent and overlooked in patients with diabetes and chronic wounds. Moreover, to date, we do not have clear recommendations or evidence about the use of nutritional supplements for improving wound healing in patients with DFU. In this article the authors briefly analyzed the current evidence on the use of nutritional supplements of proteins or amino acids, fatty acids, probiotics, vitamins, and trace elements in the wound healing process in patients with DFU.     

Hyaluronic acid production and CD44 expression in cultured dermal fibroblasts of patients with non-insulin-dependent diabetes mellitus with and without chronic ulcers on the lower extremity

It is well known that hyaluronic acid and its principal receptor, CD44, are implicated in the regulation of the tissue repair process, but their role in the formation of chronic diabetic ulcers has not been studied. Hyaluronic acid metabolism and CD44 expression are regulated by lactate, where their increased production is considered to affect the properties of fibroblasts in non-insulin-dependent diabetes mellitus. The aim of our work was to investigate the possible role of hyaluronic acid and CD44, and their regulation by lactate, in the abnormal wound healing of diabetes. Fibroblasts were derived from uninjured skin from four non-insulin-dependent diabetic patients with ulcers and four without ulcers; and from four healthy age-matched volunteers. We observed that diabetic fibroblasts of both groups produced more L-lactate ( approximately 30%) and incorporated more (3)H-glucosamine into the medium hyaluronic acid ( approximately 28%) than controls. Fibroblasts of the diabetic group with ulcers, unlike those of the group without ulcers, showed significant increases in the high molecular weight hyaluronic acid accumulation in the pericellular matrix (30.5%, p < 0.01) and CD44 expression (27.0%, p < 0.05). Exogenous L-lactate dose-dependently, and equally for all fibroblasts lines, stimulated the accumulation of medium hyaluronic acid (3.7-fold) and CD44 expression (1.5-fold). However, fibroblasts from diabetic patients with ulcers were more (1.4-fold) sensitive to L-lactate in terms of CD44 expression, and responded to L-lactate by the increased accumulation of high molecular weight hyaluronic acid in the pericellular matrix (32.1%, p < 0.01). We propose that specific properties of fibroblasts from diabetic patients with ulcers may be involved in the increased susceptibility of these patients to chronic ulceration.