Gene expression profiling of Lucilia sericata larvae extraction/secretion-treated skin wounds

Managing Wound Healing with a High-Risk Patient: A Case Report

Wound healing is a complex, multi-step process. This process begins immediately after skin damage. The outcome of wound healing depends on the quality of each stage of this process: a normal or pathological scar. Violation of wound healing entails a decrease in the function of scar tissue as well as aesthetic dissatisfaction with the patient. This problem is especially important in aesthetic surgery. Patients who have come for beauty feel frustration, obtaining pathological scars. We have been dealing with the problem of wound healing after plastic surgery for about 10 years. Our approach includes the assessment of the risk of pathological wound healing and the treatment of high-risk patients. The risk assessment includes historical data on wound healing, signs of connective tissue dysfunction (especially patients with connective tissue dysplasia), and genetic polymorphisms of genes responsible for the structure of the components of the extracellular matrix of the skin. In the future, patients with a high risk of pathological scarring can be prescribed treatment after surgery. This article presents a clinical case in which we demonstrate our approach.

The Role of Extracellular Matrix in Skin Wound Healing

Impaired wound healing is one of the unsolved problems of modern medicine, affecting patients’ quality of life and causing serious economic losses. Impaired wound healing can manifest itself in the form of chronic skin wounds or hypertrophic scars. Research on the biology and physiology of skin wound healing disorders is actively continuing, but, unfortunately, a single understanding has not been developed. The attention of clinicians to the biological and physiological aspects of wound healing in the skin is necessary for the search for new and effective methods of prevention and treatment of its consequences. In addition, it is important to update knowledge about genetic and non-genetic factors predisposing to impaired wound healing in order to identify risk levels and develop personalized strategies for managing such patients. Wound healing is a very complex process involving several overlapping stages and involving many factors. This thematic review focuses on the extracellular matrix of the skin, in particular its role in wound healing. The authors analyzed the results of fundamental research in recent years, finding promising potential for their transition into real clinical practice.

The effect of Lucilia sericata larval excretion/secretion (ES) products on cellular responses in wound healing

Chronic wounds are still regarded as a serious public health concern, which are on the increase mainly due to the changes in life styles and aging of the human population. There are different types of chronic wounds, each of which requires slightly different treatment strategies. Nevertheless, wound bed preparation is included in treatment of all types of chronic wounds and involves tissue debridement, inflammation, and infection control, as well as moisture balance and epithelial edge advancement. Maggot therapy (MT) is a form of biological debridement which involves the application of live medical grade Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae) larvae. Whereas it was initially thought to act mainly through debridement, today MT is known to influence all four overlapping physiological phases of wound repair: homeostasis, inflammation, proliferation, and remodelling/maturing. During MT, medical-grade larvae are applied either freely or enclosed in tea-bag like devices (biobag) inside the wounds, which suggests that larva excretion/secretion (ES) products can facilitate the healing processes directly without the need of direct contact with the larvae. This review summarizes the relevant literature on ES-mediated effects on the cellular responses involved in wound healing.

A molecular approach to maggot debridement therapy with Lucilia sericata and its excretions/secretions in wound healing

Chronic wounds caused by underlying physiological causes such as diabetic wounds, pressure ulcers, venous leg ulcers and infected wounds affect a significant portion of the population. In order to treat chronic wounds, a strong debridement, removal of necrotic tissue, elimination of infection and stimulation of granulation tissue are required. Maggot debridement therapy (MDT), which is an alternative treatment method based on history, has been used quite widely. MDT is an efficient, simple, cost-effective and reliable biosurgery method using mostly larvae of Lucilia sericata fly species. Larvae can both physically remove necrotic tissue from the wound site and stimulate wound healing by activating molecular processes in the wound area through the enzymes they secrete. The larvae can stimulate wound healing by activating molecular processes in the wound area through enzymes in their excretions/secretions (ES). Studies have shown that ES has antibacterial, antifungal, anti-inflammatory, angiogenic, proliferative, hemostatic and tissue-regenerating effects both in vivo and in vitro. It is suggested that these effects stimulate wound healing and accelerate wound healing by initiating a direct signal cascade with cells in the wound area. However, the enzymes and peptides in ES are mostly still undefined. Examining the molecular content of ES and the biological effects of these ingredients is quite important to illuminate the molecular mechanism underlying MDT. More importantly, ES has the potential to have positive effects on wound healing and to be used more as a therapeutic agent in the future, so it can be applied as an alternative to MDT in wound healing.

Maggot excretions/secretions promote diabetic wound angiogenesis via miR18a/19a - TSP-1 axis

AIMS

The impaired angiogenesis is one of the main factors affecting the healing of diabetic foot ulcer (DFU) wounds. Maggot debridement therapy (MDT) promotes granulation tissue growth and angiogenesis during DFU wound healing. Non-coding microRNAs can also promote local angiogenesis in DFU wounds by regulating wound repairing related gene expression. The purpose of this study was to investigate the mechanism of microRNAs in MDT promoting DFU wound angiogenesis.

METHODS

In this study, we applied MDT to treat DFU wound tissue and detect the expression of the miR-17-92 cluster. In vitro experiments, human umbilical vein endothelial cells (HUVECs) were treated with maggot excretions/secretions (ES), the miR-17-92 cluster and the predicted target gene expression were measured. Tube formation assay and cell scratch assay were performed when inhibition of miR-18a/19a or overexpression of thrombospondin-1 (TSP-1) were used in this study.

RESULTS

miR-18a/19a transcription significantly up-regulated and TSP-1 expression down-regulated in patients wound tissue and in HUVECs. Inhibition of miR-18a/19a or overexpression of TSP-1 partially blocked the migration and tube formation ability stimulated by ES.

CONCLUSION

Targeted activation of miR-18a/19a transcription levels and subsequent regulation of TSP-1 expression may be a novel therapeutic strategy for DFU.

Anesthesia may alter mRNA expression of certain wound healing-associated genes in dermal wound environment of the rats

Some anesthetics including ketamine/xylazine and thiopental have been shown to alter the expression of genes related with inflammatory cytokines and chemokines in previous studies unassociated with wound healing, arising the question of whether commonly used anesthetics in wound healing models could interfere with the transcriptional responses of the genes associated with skin wound healing. The gene expression profile in wound biopsies of rats who received widely used anesthetics doses of intraperitoneal ketamine/xylazine (50 mg/kg and 10 mg/kg) or thiopental (50 mg/kg) in comparison with control rats was analyzed by monitoring the expression of genes effective on various phases of wound healing. The expression levels of 84 genes were determined on 3rd, 7th and 14th days of post-wounding using a qPCR array system. Of the genes either up or downregulated fivefolds or more, three (Egf, Col5a1 and Cxcl3) and two (Tgfa and Il2) genes were found to be the most responsive ones to ketamine/xylazine or thiopental anesthesia respectively in a period of 14 days after correction for multiple testing. However, up to 22 and 24 genes for ketamine/xylazine and thiopental were found to be differentially expressed in the same period without correction for multiple-comparisons testing (p < 0.05). In conclusion, our data suggest that ketamine/xylazine and thiopental may alter the transcriptional responses of some genes associated with wound healing in rats. We strongly suggest to consider the possible alteration effect of these anesthetics on gene expression in animal models of dermal wound healing.

Regulation of MMP 2 and MMP 9 expressions modulated by AP-1 (c-jun) in wound healing: improving role of Lucilia sericata in diabetic rats

AIMS

Lucilia sericata larvae have been successfully used on healing of wounds in the diabetics. However, the involvement of the extraction/secretion (ES) products of larvae in the treatment of diabetic wounds is still unknown. Activator protein-1 (AP-1) transcription, composed of c-jun and c-Fos proteins, has been shown to be the principal regulator of multiple MMP transcriptions under a variety of conditions, also in diabetic wounds. Specifically, MMP-2 and MMP-9's transcriptions are known to be modulated by AP-1. c-jun has been demonstrated to be a repressor of p53 in immortalized fibroblasts. The aim of the present study is to investigate the effects of L. sericata ES on the expression of AP-1 (c-jun), p53, MMP-2, and MMP-9 in wound biopsies dissected from streptozotocin induced diabetic rats.

METHODS

The expression levels of MMP-2, MMP-9, c-jun and p53 in dermal tissues were determined at days 0, 3, 7 and 14 after wounding, using immunohistochemical analysis and quantitative real-time PCR.

RESULTS

The treatment with ES significantly decreased through inflammation-based induction of MMP-2 and MMP-9 expression levels in the wounds of diabetic groups, compared to control groups at the third day of wound healing. At the 14th day, there were dramatic decreases in expression of c-jun, MMP-9, and p53 in ES-treated groups, compared to the diabetic group (P < 0.001, P < 0.05 and P < 0.01, respectively).

CONCLUSION

ES products of L. sericata may enhance the process of wound healing in phases of inflammation, proliferation, and re-epithelization, essentially via regulating c-jun expression and modulating MMP-2 and MMP-9 expressions.

The transcriptional responses of cultured wound cells to the excretions and secretions of medicinal Lucilia sericata larvae

Maggots, through their excretions and secretions (ES), promote wound healing by removing necrotic tissue, counter bacterial infection, and activate wound associated cells. We investigated the effects of a physiological dose of maggot ES on four wound-associated cell types in vitro with Affymetrix gene expression arrays; keratinocytes, endothelial cells, fibroblasts, and monocytes. Keratinocytes showed the fewest (n = 5; p < 0.05, fold-change ±2) and smallest fold-changes (up to 2.32×) in gene expression and conversely THP1 monocytes had the most (n = 233) and greatest magnitude (up to 44.3×). There were no genes that were altered in all four cell-lines. Gene pathway analysis identified an enrichment of immune response pathways in three of the treated cell-lines. Analyses by quantitative RT-PCR found many genes dynamically expressed in ES dose dependent manner during the three day treatments. Phenotype analyses, however, found no effects of ES on cell viability, proliferation, migration and angiogenesis. ES was 100× less potent at triggering IL-8 secretion than fibroblasts treated with purified bacterial lipopolysaccharide (LPS; in equivalent amounts to that found in ES; ∼40 EU/ml). Furthermore, co-treatment with LPS and ES decreased the LPS-alone triggered IL-8 secretion by 13%. Although ES had no direct effect on wound cell phenotypes it did partially reduce the immune response to bacterial LPS exposure. These observations were consistent with the profile of transcriptional responses that were dominated by modulation of immune response genes. Maggot therapy may therefore improve wound healing through the secondary effects of these gene changes in the wound cells.

Treatment of pressure ulcers with larvae of Lucilia sericata

Objectives

This study aims to investigate the use of the Lucilia sericata larvae in patients with decubitus ulcers resistant to hyperbaric oxygen treatment, vacuum-assisted closure, surgical debridement, and other conventional therapies.

Patients and methods

A total of 36 patients (21 females, 15 males; mean age 63.7 years; range 16 to 90 years) who were admitted to our hospital for decubitus ulcers between February 2011 and July 2016 were included in our study. All patients had one or more lesions in the sacral region, trochanteric area, dorsal region, or on the heel of the foot. Nine patients had spinal cord injuries, six of them were injured during a car accident, and three of them had spinal cord injuries due to gunshot. One patient had concomitant lung cancer, one had heart failure, and two patients had a diagnosis of multiple sclerosis. Thirty three of 36 patients were admitted to the wound therapy unit within the department of emergency medicine, and three were admitted to the physical therapy and rehabilitation clinic. For each patient, Lucilia sericata maggots were applied on the lesions for 72 hours and, then, washed away. This procedure was repeated two times a week. Twenty nine patients (78.9%) had four to six sessions and seven patients (21.1%) had eight to 12 sessions.

Results

Twenty nine lesions (78.9%) were Grade 2 and 3 and were completely healed after four to eight treatment sessions, while seven lesions (21.1%) were completely cured at the end of 10 to 14 sessions. There was complete clearance of necrotic debris at the end of two sessions within the first week for 15 lesions, whereas 10 lesions (27.8%) were cured after four sessions within two weeks, seven lesions (19.4%) within five sessions after three weeks, and four lesions (11.1%) were treated at the end of seven sessions for four weeks. All the necrotic crusts over the surface of the ulcers were cleaned and bad odor of the lesions disappeared.

Conclusion

Lucilia sericata larvae debridement is a rapid and effective treatment option for the management of chronic decubitus ulcers which are resistant to conventional therapies and other treatment modalities such as hyperbaric oxygen, vacuum-assisted closure, and surgical debridement.