Profiles of matrix metalloproteinases and their tissue inhibitors in intraperitoneal drainage fluid: relationship to wound healing

Recent advancements in drug delivery system of flavonoids with a special emphasis on the flavanone naringenin: exploring their application in wound healing and associated processes

Numerous flavonoids have been identified in citrus fruits which show potential to cure several complex diseases. These natural polyphenolic bioactive compounds are the secondary metabolites of various plants, among which naringenin has been explored in several pre-clinical research for its beneficial role in promoting health by modulating various biochemical processes. Its antioxidant, anti-inflammatory, and anti-microbial effects have been projected toward healing of wounds. Further, its application has also been shown to regrow vascular networks, which are known to facilitate the healing of chronic wounds. Thus, the potential of naringenin to modulate various molecular pathways aids in the healing process of wounds. Considering the recent literature, an update has been attempted to present the correlation between the healing mechanisms of wounds by the application of naringenin. Furthermore, the application of naringenin is challenging because of its properties of poor solubility and limited permeability, which can be overcome by the nanotechnology platform. Thus, several nanocarriers that have been employed for the improvement of naringenin delivery are highlighted. Thereby, it can be concluded that a suitable nanocarrier of naringenin could be an effective tool in treating wounds to improve the quality of life of such patients.

The Extracellular Matrix: Its Composition, Function, Remodeling, and Role in Tumorigenesis

The extracellular matrix (ECM) is a ubiquitous member of the body and is key to the maintenance of tissue and organ integrity. Initially thought to be a bystander in many cellular processes, the extracellular matrix has been shown to have diverse components that regulate and activate many cellular processes and ultimately influence cell phenotype. Importantly, the ECM's composition, architecture, and stiffness/elasticity influence cellular phenotypes. Under normal conditions and during development, the synthesized ECM constantly undergoes degradation and remodeling processes via the action of matrix proteases that maintain tissue homeostasis. In many pathological conditions including fibrosis and cancer, ECM synthesis, remodeling, and degradation is dysregulated, causing its integrity to be altered. Both physical and chemical cues from the ECM are sensed via receptors including integrins and play key roles in driving cellular proliferation and differentiation and in the progression of various diseases such as cancers. Advances in 'omics' technologies have seen an increase in studies focusing on bidirectional cell-matrix interactions, and here, we highlight the emerging knowledge on the role played by the ECM during normal development and in pathological conditions. This review summarizes current ECM-targeted therapies that can modify ECM tumors to overcome drug resistance and better cancer treatment.

Wound fluid sampling methods for proteomic studies: A scoping review

Understanding why some wounds are hard to heal is important for improving care and developing more effective treatments. The method of sample collection used is an integral step in the research process and thus may affect the results obtained. The primary objective of this study was to summarise and map the methods currently used to sample wound fluid for protein profiling and analysis. Eligible studies were those that used a sampling method to collect wound fluid from any human wound for analysis of proteins. A search for eligible studies was performed using MEDLINE, Embase and CINAHL Plus in May 2020. All references were screened for eligibility by one reviewer, followed by discussion and consensus with a second reviewer. Quantitative data were mapped and visualised using appropriate software and summarised via a narrative summary. After screening, 280 studies were included in this review. The most commonly used group of wound fluid collection methods were vacuum, drainage or use of other external devices, with surgical wounds being the most common sample source. Other frequently used collection methods were extraction from absorbent materials, collection beneath an occlusive dressing and direct collection of wound fluid. This scoping review highlights the variety of methods used for wound fluid collection. Many studies had small sample sizes and short sample collection periods; these weaknesses have hampered the discovery and validation of novel biomarkers. Future research should aim to assess the reproducibility and feasibility of sampling and analytical methods for use in larger longitudinal studies.

Erbium, chromium-doped: yttrium, scandium, gallium, garnet and diode lasers in the treatment of peri-implantitis: clinical and biochemical outcomes in a randomized-controlled clinical trial

This study aims to evaluate the effects of 940 nm diode laser and 2780 nm erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser used in addition to mechanical therapy in the non-surgical treatment of peri-implantitis on clinical parameters and matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels in the peri-implant crevicular fluid. A total of 50 patients with peri-implantitis were randomized into three groups to receive peri-implant treatment. The control group (n = 17) only received conventional non-surgical mechanical therapy. The trial groups [(diode group (n = 16) and Er,Cr:YSGG group (n = 17)] received dental laser in addition to mechanical therapy. Gingival index (GI), plaque index (PI), bleeding on probing, probing depth (PD), MMP-9, and TIMP-1 levels were assessed at baseline (T0) and at 6 months after treatment (T1). The GI, PI, and PD significantly decreased in all groups at T1, compared to T0 (p < 0.05). The decrease in the PD was similar between the control and diode groups with Er,Cr:YSGG providing more reduction (1.16 ± 0.64 mm) than either method (p = 0.032). A significant intra-group decrease in MMP-9 level was only observed in the Er,Cr:YSGG group (p = 0.009). The decrease in TIMP-1 level from T0 to T1 was similar between the control and the diode groups (p > 0.05) and it was significantly lower than the decrease in the Er,Cr:YSGG group (p < 0.05). Addition of diode laser to non-surgical mechanical therapy does not provide any additional benefit for treatment outcomes. The Er,Cr:YSGG laser seems to be more efficient both at clinical and molecular levels. ClinicalTrials, ID: NCT04730687. Registered 13 April 2021. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04730687.

Wound healing properties of flavonoids: A systematic review highlighting the mechanisms of action

BACKGROUND

Flavonoids are a class of compounds with a wide variety of biological functions, being an important source of new products with pharmaceutical potential, including treatment of skin wounds.

PURPOSE

This review aimed to summarize and evaluate the evidence in the literature in respect of the healing properties of flavonoids on skin wounds in animal models.

STUDY DESIGN

This is a systematic review following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

METHODS

This was carried out through a specialized search of four databases: PubMed, Scopus, Web of Science and Embase. The following keyword combinations were used: "flavonoidal" OR "flavonoid" OR "flavonoidic" OR "flavonoids" AND "wound healing" as well as MeSH terms, Emtree terms and free-text words.

RESULTS

Fifty-five (55) articles met the established inclusion and exclusion criteria. Flavonoids presented effects in respect of the inflammatory process, angiogenesis, re-epithelialization and oxidative stress. They were shown to be able to act on macrophages, fibroblasts and endothelial cells by mediating the release and expression of TGF-β1, VEGF, Ang, Tie, Smad 2 and 3, and IL-10. Moreover, they were able to reduce the release of inflammatory cytokines, NFκB, ROS and the M1 phenotype. Flavonoids acted by positively regulating MMPs 2, 8, 9 and 13, and the Ras/Raf/MEK/ERK, PI3K/Akt and NO pathways.

CONCLUSION

Flavonoids are useful tools in the development of therapies to treat skin lesions, and our review provides a scientific basis for future basic and translational research.

Predictive and Diagnostic Biomarkers of Anastomotic Leakage: A Precision Medicine Approach for Colorectal Cancer Patients

Development of an anastomotic leak (AL) following intestinal surgery for the treatment of colorectal cancers is a life-threatening complication. Failure of the anastomosis to heal correctly can lead to contamination of the abdomen with intestinal contents and the development of peritonitis. The additional care that these patients require is associated with longer hospitalisation stays and increased economic costs. Patients also have higher morbidity and mortality rates and poorer oncological prognosis. Unfortunately, current practices for AL diagnosis are non-specific, which may delay diagnosis and have a negative impact on patient outcome. To overcome these issues, research is continuing to identify AL diagnostic or predictive biomarkers. In this review, we highlight promising candidate biomarkers including ischaemic metabolites, inflammatory markers and bacteria. Although research has focused on the use of blood or peritoneal fluid samples, we describe the use of implantable medical devices that have been designed to measure biomarkers in peri-anastomotic tissue. Biomarkers that can be used in conjunction with clinical status, routine haematological and biochemical analysis and imaging have the potential to help to deliver a precision medicine package that could significantly enhance a patient's post-operative care and improve outcomes. Although no AL biomarker has yet been validated in large-scale clinical trials, there is confidence that personalised medicine, through biomarker analysis, could be realised for colorectal cancer intestinal resection and anastomosis patients in the years to come.

Matrix metalloproteinase-9 in relation to patients with complications after colorectal surgery: a systematic review

PURPOSE

Anastomotic leakage (AL) is the most severe complication following colorectal resection and is associated with increased mortality. The main group of enzymes responsible for collagen and protein degradation in the extracellular matrix is matrix metalloproteinases. The literature is conflicting regarding anastomotic leakage and the degradation of extracellular collagen by matrix metalloproteinase-9 (MMP-9). In this systematic review, the possible correlation between anastomotic leakage after colorectal surgery and MMP-9 activity is investigated.

METHODS

Embase, MEDLINE, Cochrane, and Web of Science databases were searched up to 3 February 2020. All published articles that reported on the relationship between MMP-9 and anastomotic leakage were selected. Both human and animal studies were found eligible. The correlation between MMP-9 expression and anastomotic leakage after colorectal surgery.

RESULTS

Seven human studies and five animal studies were included for analysis. The human studies were subdivided into those assessing MMP-9 in peritoneal drain fluid, intestinal biopsies, and blood samples. Five out of seven human studies reported elevated levels of MMP-9 in patients with anastomotic leakage on different postoperative moments. The animal studies demonstrated that MMP-9 activity was highest in the direct vicinity of an anastomosis. Moreover, MMP-9 activity was significantly reduced in areas further proximally and distally from the anastomosis and was nearly or completely absent in uninjured tissue.

CONCLUSION

Current literature shows some relation between MMP-9 activity and colorectal AL, but the evidence is inconsistent. Innovative techniques should further investigate the value of MMP-9 as a clinical biomarker for early detection, prevention, or treatment of AL.

Dietary administration of the probiotic Shewanella putrefaciens to experimentally wounded gilthead seabream (Sparus aurata L.) facilitates the skin wound healing

The effect of the probiotic Shewanella putrefaciens Pdp11 (SpPdp11) was studied on the skin healing of experimentally wounded gilthead seabream (Sparus aurata L.). Two replicates (n = 12) of fish were fed CON diet or SP diet for 30 days. Half of the fish were sampled while the others were injured and sampled 7 days post-wounding. Results by image analysis of wound areas showed that SpPdp11 inclusion facilitated wound closure. Compared with the CON group, fish in SP group sampled 7 days post-wounding had a significantly decreased serum AST and increased ALB/GLOB ratio. Furthermore, protease and peroxidase activities were significantly increased in skin mucus from fish in SP group sampled 7 days post-wounding, compared with those fed CON diet. Additionally, SP diet up-regulated the gene expression of antioxidant enzymes, anti-inflammatory cytokines, and re-epithelialization related genes in the fish skin. Furthermore, significant decreases in pro-inflammatory cytokines expression were detected in fish from SP group, respect to control ones. Overall, SpPdp11 inclusion facilitated the wound healing and the re-epithelialization of the damaged skin, alleviated the inflammatory response in the wound area through intensifying the antioxidant system, and enhancing the neo-vascularization and the synthesis of matrix proteins in the skin wound sites of fish.

A multicentre cohort study of serum and peritoneal biomarkers to predict anastomotic leakage after rectal cancer resection

AIM

Anastomotic leakage (AL) is one of the most feared complications after rectal resection. This study aimed to assess a combination of biomarkers for early detection of AL after rectal cancer resection.

METHOD

This study was an international multicentre prospective cohort study. All patients received a pelvic drain after rectal cancer resection. On the first three postoperative days drain fluid was collected daily and C-reactive protein (CRP) was measured. Matrix metalloproteinase-2 (MMP2), MMP9, glucose, lactate, interleukin 1-beta (IL1β), IL6, IL10, tumour necrosis factor alpha (TNFα), Escherichia coli, Enterococcus faecalis, lipopolysaccharide-binding protein and amylase were measured in the drain fluid. Prediction models for AL were built for each postoperative day using multivariate penalized logistic regression. Model performance was estimated by the c-index for discrimination. The model with the best performance was visualized with a nomogram and calibration was plotted.

RESULTS

A total of 292 patients were analysed; 38 (13.0%) patients suffered from AL, with a median interval to diagnosis of 6.0 (interquartile ratio 4.0-14.8) days. AL occurred less often after partial than after total mesorectal excision (4.9% vs 15.2%, P = 0.035). Of all patients with AL, 26 (68.4%) required reoperation. AL was more often treated by reoperation in patients without a diverting ileostomy (18/20 vs 8/18, P = 0.03). The prediction model for postoperative day 1 included MMP9, TNFα, diverting ileostomy and surgical technique (c-index = 0.71). The prediction model for postoperative day 2 only included CRP (c-index = 0.69). The prediction model for postoperative day 3 included CRP and MMP9 and obtained the best model performance (c-index = 0.78).

CONCLUSION

The combination of serum CRP and peritoneal MMP9 may be useful for earlier prediction of AL after rectal cancer resection. In clinical practice, this combination of biomarkers should be interpreted in the clinical context as with any other diagnostic tool.

Metalloproteinases in chronic and acute wounds: A systematic review and meta-analysis

A systematic review and meta-analysis were undertaken in order to explore the influence of matrix metalloproteinases and their diagnostic methods in chronic and acute wounds. Searches were conducted in the PubMed (Medline) and Embase (Elsevier) databases from inception to late November 2017. We included clinical trials enrolling patients with cutaneous chronic and acute wounds where a validated diagnostic method was employed for metalloproteinases. We excluded in vitro, animal or preclinical studies, nonoriginal articles, and studies without available data for analysis. In addition, references of narrative and systematic reviews were scrutinized for additional articles. Eight studies met the inclusion criteria. Results revealed that the most frequently determined matrix metalloproteinases were MMP-2 and MMP-9, and were found in 54.5% of wounds. MMP-9 was present in more than 50% of the chronic wounds with a range from 37 to 78%. However, metalloproteinases were found in only 20% of acute wounds, and other types of metalloproteinases were also observed (MMP-2 and MMP-3). On the basis of the available evidence, high levels of metalloproteinases have been correlated with significantly delayed wound healing in wounds of a variety of etiologies.

Bilirubin, urobilinogen, pancreas elastase and bile acid in drain fluid. The GBUP-study: Analysis of biomarkers for a colorectal anastomotic leakage

Purpose

A colorectal anastomotic leakage (CAL) is a major complication after colorectal surgery and leads to high rates of morbidity and prolonged hospital stay. The study aims to evaluate the benefit of using bilirubin, urobilinogen, pancreas elastase and bile acid in the drain fluid (DF) as a predictive marker for the CAL.

Methods

From June 2015 to October 2017 100 patients, who underwent left hemicolectomy (LH), sigma resection (SR), high anterior resection (HAR), low anterior resection (LAR) or reversal of Hartmann's Procedure (ROHP) were included in this monocentric non-randomized prospective clinical trial. During the first four postoperative days (POD) the concentration of bilirubin, urobilinogen, pancreas elastase and bile acid in the DF was measured.

Results

In total 100 patients were recruited. 17 were excluded due to intraoperative decisions to conduct a protective stoma. 6 patients had a CAL. The patients of the control group (n = 77) and the patients who suffered from a CAL (n = 6) had no increased concentration of urobilinogen and pancreas elastase in the DF. The concentration of bile acid in the DF of the patients who suffered from a CAL differed from those of the control group on the 4th POD (p = 0.055).

The concentration of bilirubin in the DF of the patients who suffered from a CAL significantly differed from those of the control group on the 1st POD (p = 0.031) and on the 3rd POD (p = 0.041).

Conclusion

Bilirubin and bile acid in the DF may function as a predictive marker for a CAL.

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Bilirubin in the DF may function as a predictive marker for a CAL.

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Bile acid in the DF may function as a predictive marker for a CAL.

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Pancreas elastase in the DF did not seem to be a predictive marker for a CAL.

Healing and mucosal immunity in the skin of experimentally wounded gilthead seabream (Sparus aurata L)

Skin lesions are very common in fisheries, increasing the risk of pathogens entering through the wounded skin of the fish. In the present assay, the progression of wound healing was studied over a 7 day period in gilthead seabream (Sparus aurata L.) after making experimental wounds in two different locations: above (group A) or below (group B) the lateral line. Macroscopic observation confirmed faster wound healing of the wounds of fish from group B. Furthermore, several immune-related components were studied in the skin mucus of wounded fish to ascertain whether wounding altered the mucus composition compared with the values obtained from non-wounded fish (group C, control). Significant variations were detected depending on both the site of the wound and the studied parameter. At the same time, the gene expression profile of several immune-relevant genes, including pro-inflammatory (il1b,il6, tnfa), anti-inflamamtory (tgfb, il10), immunoglobulins (ighm, ight), involved in oxidative stress (sod, cat) and in skin regeneration (krt1and grhl1) were studied in the three groups of fish (A, B and C). The results throw further light on the complex process of skin wound healing in fish, since substantial changes in the skin mucus and in the skin gene expression originated by the presence of wounds were observed. This work underline some important differences depending on the place of the fish body where the wound is located. Of particular note was the fact that such changes depended on the site of the wound.

Peritoneal fluid biomarkers in the detection of colorectal anastomotic leaks: a systematic review

PURPOSE

Anastomotic leak (AL) in colorectal surgery leads to significant morbidity, mortality and poorer oncological outcomes. Diagnosis of AL is frequently delayed as current methods of detection are not 100% sensitive or specific. 'Biomarkers', such as cytokines and markers of ischaemia, from the milieu of the anastomosis may aid early detection. This paper aims to review the evidence for their role in AL detection, allowing identification of targets for future research.

METHODS

A systematic review was performed using PubMed, MEDLINE and Cochrane Library databases. Papers concerning detection or prediction of AL with biomarkers were identified. References within the papers were used to identify further relevant articles.

RESULTS

Research has taken place in small cohorts with varying definitions of AL. Lactate has consistently been shown to be elevated in patients with intra-abdominal complications and ALs. pH on post-operative day 3 showed excellent specificity. Despite mixed results, a meta-analysis found that the cytokines tumour necrosis factor-α and interleukin-6 were elevated early in AL. Detection of bacteria in drain fluid by RT-PCR has good specificity but a high rate of false positives.

CONCLUSIONS

Peritoneal cytokines, lactate and pH have the potential to identify AL early. The consistency of the results for lactate and pH, alongside the fact that they are easy, quick and inexpensive to test, makes them the most attractive targets. Studies in larger cohorts with standardized definitions of AL are required to clarify their usefulness. Emerging biosensor technology may facilitate the development of small, low-cost and degradable intra-abdominal devices to measure peritoneal fluid biomarkers.

Integrated approach to colorectal anastomotic leakage: Communication, infection and healing disturbances

Colorectal anastomotic leakage (CAL) remains a major complication after colorectal surgery. Despite all efforts during the last decades, the incidence of CAL has not decreased. In this review, we summarize the available strategies regarding prevention, prediction and intervention of CAL and categorize them into three categories: communication, infection and healing disturbances. These three major factors actively interact during the onset of CAL. We aim to provide an integrated approach to CAL based on its etiology. The intraoperative air leak test, intraoperative endoscopy, radiological examinations and stoma construction mainly aim to detect and to prevent communication between the intra- and extra-luminal content. Other strategies including postoperative drainage, antibiotics, and infectious-parameter evaluation are intended to detect and prevent anastomotic or peritoneal infection. Most currently available interventions for CAL focus on the control of communication and infection, while strategies targeting the healing disturbances such as lifestyle changes, oxygen therapy and evaluation of metabolic biomarkers still lack wide clinical application. This simplified categorization may contribute to an integrated understanding of CAL. We strongly believe that this integrated approach should be taken into consideration during clinical practice. An integrated approach to CAL could contribute to a better understanding of the etiology of CAL and eventually better patient outcome.

Microenvironment and microbiology of skin wounds: the role of bacterial biofilms and related factors

Wound healing is a systemic response to injury that impacts the entire body and not just the site of tissue damage; it represents one of the most complex biological processes. Our knowledge of wound healing continues to evolve and it is now clear that the wound microenvironment plays a crucial role. The interactions between cells and the surface microenvironment, referred to as the "biofilm," contributes to skin homeostasis and healing. Understanding the functional complexity of the wound microenvironment informs how various factors such as age, ischemia, or bacterial infections can impair or arrest the normal healing processes, and it also allows for the possibility of acting therapeutically on healing defects with microenvironment manipulation. Microbes represent a particularly important factor for influencing the wound microenvironment and therefore wound healing. Moreover, the role of infections, particularly those that are sustained by biofilm-forming bacteria, is mutually related to other microenvironment aspects, such as humidity, pH, metalloproteinases, and reactive oxygen species, on which the modern research of new therapeutic strategies is focused. Today, chronic wounds are a rapidly growing health care burden and it is progressively understood that many non-healing wounds might benefit from therapies that target microorganisms and their biofilm communities. There is no doubt that host factors like perfusion impairments, venous insufficiency, pressure issues, malnutrition, and comorbidities strongly impact the healing processes and therefore must be targeted in the therapeutic management, but this approach might be not enough. In this article, we detail how bacterial biofilms and related factors impair wound healing, the reasons they must be considered a treatment target that is as important as the host's local and systemic pathologic conditions, and the latest therapeutic strategies derived from the comprehension of the wound microenvironment.

Ovine-Based Collagen Matrix Dressing: Next-Generation Collagen Dressing for Wound Care

Significance: Broad-spectrum metalloproteinase (MMP) reduction along with inherent aspects of an extracellular matrix (ECM) dressing can bring about improved wound healing outcomes and shorter treatment duration. Initial reports of clinical effectiveness of a new ovine-based collagen extracellular matrix (CECM) dressing demonstrate benefits in chronic wound healing. Recent Advances: CECM dressings are processed differently than oxidized regenerated cellulose/collagen dressings. CECM dressings consist primarily of collagens I and III arranged as native fibers that retain the three-dimensional architecture present in tissue ECM. As such, ovine-based ECM dressings represent a new generation of collagen dressings capable of impacting a broad spectrum of MMP excess known to be present in chronic wounds. Critical Issues: While MMPs are essential in normal healing, elevated presence of MMPs has been linked to wound failure. Collagen has been shown to reduce levels of MMPs, acting as a sacrificial substrate for excessive proteases in a chronic wound. Preserving collagen dressings in a more native state enhances bioactivity in terms of the ability to affect the chronic wound environment. Clinical observation and assessment may not be sufficient to identify a wound with elevated protease activity that can break down ECM, affect wound fibroblasts, and impair growth factor response. Future Directions: Collagen dressings that target broad-spectrum excessive MMP levels and can be applied early in the course of care may positively impact healing rates in difficult wounds. Next-generation collagen dressings offer broader MMP reduction capacity while providing a provisional dermal matrix or ECM.

Emerging drugs for the treatment of wound healing

INTRODUCTION

Wound healing can be characterized as underhealing, as in the setting of chronic wounds, or overhealing, occurring with hypertrophic scar formation after burn injury. Topical therapies targeting specific biochemical and molecular pathways represent a promising avenue for improving and, in some cases normalizing, the healing process.

AREAS COVERED

A brief overview of both normal and pathological wound healing has been provided, along with a review of the current clinical guidelines and treatment modalities for chronic wounds, burn wounds and scar formation. Next, the major avenues for wound healing drugs, along with drugs currently in development, are discussed. Finally, potential challenges to further drug development, and future research directions are discussed.

EXPERT OPINION

The large body of research concerning wound healing pathophysiology has provided multiple targets for topical therapies. Growth factor therapies with the ability to be targeted for localized release in the wound microenvironment are most promising, particularly when they modulate processes in the proliferative phase of wound healing.

[Impact of the local application of collagen on the activity of reparative processes in the lower extremity soft tissue of patients with diabetic foot syndrome]

AIM

To estimate of the rate of reparative processes in the lower extremity (LE) soft tissues of patients with diabetic foot (DF) syndrome in the local application of collagen-containing dressings (CCD) versus standard medical therapy.

MATERIAL AND METHODS

The clinical (sizes, tissue oxygenation), histological, and immunohistochemical markers of reparative processes in LE soft tissues were analyzed in patients with diabetes mellitus during the local application of collagen-containing wound dressings versus standard treatment. Forty-two patients with postrevascularization neuropathic and neuroischemic DF syndrome were examined after standard surgical wound treatment. In the perioperative period, 21 patients received local treatment using CCD and 21 patients had standard treatment.

RESULTS

In the patients using CCD, the area and depth of wound defects could be decreased by 26.4±17.2 and 30.4±25.6%, respectively (p=0.002 vs baseline). In the control group, those were 17.0±19.4 and 16.6±21.6%, respectively (p=0.002). Percutaneous oximetry assessment indicated significantly higher local microhemodynamics in the local collagen treatment group (p<0.05). According to the data of histological examination of wound defect tissues, after 10-day treatment, Group 1 showed a 80% reduction in edema (p<0.05), a 90% disappearance of inflammatory infiltrates (p<0.05), and formation of mature granulation tissue (p<0.05). Immunohistochemical examination revealed a more pronounced rise in the count of macrophages in the derma (p<0.05). When CCD was applied, the level of matrix metalloproteinase tended to more markedly decrease as compared to that in the control group.

CONCLUSION

The findings suggest that the activity of reparative processes in LE soft tissues is enhanced in diabetic patients receiving local collagen therapy versus those having standard treatment. This manifests itself as a decrease in both the area and depth of wounds, enhancement of local tissue perfusion, a reduction of inflammation and a rapider wound transfer from proliferation to the epithelialization phase, as supported by histological and immunohistochemical findings.

High matrix metalloproteinase levels are associated with dermal graft failure in diabetic foot ulcers

The aim of our study is to analyze factors, including matrix metalloproteinase (MMP) levels, that could influence the integration of dermal grafts in diabetic foot ulcers. From September 2012 to September 2013, 35 diabetic patients with IIA lesion (Texas Wound Classification) and an extensive foot tissue loss were considered suitable for dermal graft. Before the enrollment we ensured the best local conditions: adequate blood supply, control of infection, and offloading. The MMP level of each lesion was evaluated blindly before the application of dermal substitutes. At 1-month follow-up, we analyzed the correlation between clinical patient characteristics, local wound features including MMP levels, dermal substitute applied, and the outcome expressed in terms of dermal graft integration. We observed dermal graft integration in 28/35 patients (80% of our population). In multivariate analysis high MMP level was the only negative predictor for dermal graft integration (P < .0007). In addition, we divided the patients into 2 groups according to MMP levels: group 1 with low protease activity (24 patients) and group 2 with elevated protease activity (11 patients). The integration of the dermal graft was 100% in group 1 (n = 24 patients) and 36.4% in group 2 (n = 4patients), P < .0001. According to our data, the evaluation of MMP levels may be useful to choose the right strategy to get the best results in terms of clinical success and cost saving. However, further studies are necessary to confirm these findings.

Peri-implant versus periodontal wound healing

AIM

Peri-implant gingival healing following one-stage implant placement was investigated and compared to periodontal healing.

METHODS

Healing at surgical sites [implant (I) and adjacent teeth (T+)] was compared to non-operated tooth (T-) in non-smokers receiving one-stage implant. Periodontal Indices (PI, GI) were recorded at surgery and up to 12 weeks post-operatively. Peri-implant (PICF) and gingival crevicular fluids (GCF) were analysed for cytokines, collagenases and inhibitors. Data were analysed by linear mixed model regression analysis and repeated measures anova.

RESULTS

Forty patients (22 females; 21-74 years old) completed the study. Surgical site GI, increased at week 1, decreased significantly during early healing (weeks 1-3; p = 0.0003) and continually decreased during late healing (weeks 6-12) for I (p < 0.01). PICF volume decreased threefold by week 12 (p = 0.0003). IL-6, IL-8, MIP-1β and TIMP-1 levels significantly increased at surgical sites at week one, significantly decreasing thereafter (p < 0.016). Week one IL-6, IL-8 and MIP-1β levels were ~threefold higher and TIMP-1 levels 63% higher, at I compared to T+ (p = 0.001).

CONCLUSION

Peri-implant gingival healing, as determined by crevicular fluid molecular composition, differs from periodontal healing. The observed differences suggest that peri-implant tissues, compared to periodontal tissues, represent a higher pro-inflammatory state.

Wound Fluid in Diabetic Foot Ulceration

Valid and reproducible sampling techniques as well as processing protocols are required for the assessment of biomarkers and mediators contained in wound exudate. Moreover, the ideal technique should be easy to use even in daily clinical routine. This is challenging since wound fluid represents an inhomogeneous mixture of different exogenous and endogenous sources. Analyzing wound fluid, however, may facilitate clinical decision making. Many techniques for obtaining wound fluid have been described. There is very little validation data, and the array of different techniques appears confusing. Structuring and new standards are needed to avoid wound fluid sampling yielding an “undefined soup.” A lot of wound fluid parameters have been analyzed, although none of them have made its way into clinical practice. Nevertheless, basic principles of wound healing have been established from wound fluid analysis. With adequate techniques suitable for daily practice, basic research might foster our clinical understanding of wound healing with implications for new therapies. So far, research has mainly concentrated on analyzing available sample material with respect to either a wide variety of analytes or comparing acute with chronic wound exudate. Clinical endpoints such as healing or wound infection as well as longitudinal data may indeed be more valuable for clinical practice, enabling the discovery of meaningful biomarkers using a suitable technique.

The effect of glucagon-like Peptide-2 receptor agonists on colonic anastomotic wound healing

Background. Glucagon-like peptide 2 (GLP-2) is an intestinal specific trophic hormone, with therapeutic potential; the effects on intestinal healing are unknown. We used a rat model of colonic healing, under normoxic, and stress (hypoxic) conditions to examine the effect of GLP-2 on intestinal healing. Methods. Following colonic transection and reanastomosis, animals were randomized to one of six groups (n = 8/group): controls, native GLP-2, long-acting GLP-2 (GLP-2- MIMETIBODY, GLP-2-MMB), animals were housed under normoxic or hypoxic (11%  O₂) conditions. Animals were studied five days post-operation for anastomotic strength and wound characteristics. Results. Anastomotic bursting pressure was unchanged by GLP-2 or GLP-2-MMB in normoxic or hypoxic animals; both treatments increased crypt cell proliferation. Wound IL-1β increased with GLP-2; IFNγ with GLP-2 and GLP-2-MMB. IL-10 and TGF-β were decreased; Type I collagen mRNA expression increased in hypoxic animals while Type III collagen was reduced with both GLP-2 agonists. GLP-2 MMB, but not native GLP-2 increased TIMP 1-3 mRNA levels in hypoxia. Conclusions. The effects on CCP, cytokines and wound healing were similar for both GLP-2 agonists under normoxic and hypoxic conditions; anastomotic strength was not affected. This suggests that GLP-2 (or agonists) could be safely used peri-operatively; direct studies will be required.

Effect of activation of viral receptors on the gelatinases MMP-2 and MMP-9 in human mesothelial cells

BACKGROUND

Extracellular matrix (ECM) not only provides molecular and spatial information that influence cell proliferation, differentiation and apoptosis but also has the potential to bind and present or release cytokines and cytotactic factors. Synthesis and degradation of extracellular matrix components are balanced by matrix metalloproteinases (MMP) and their inhibitors. In the pericardium as well as in the pleural and peritoneal cavities a multitude of clinically relevant disease states ranging from inflammation to fibrosis and tumor invasion result from altered regulation of MMP activity and are known to be associated with viral disease.

METHODS

Therefore, the functional linkage between viral receptors of the innate immune system, the toll-like receptors (TLR), and control of MMP activity was exemplarily analyzed by stimulating human mesothelial cells with poly (I:C) RNA.

RESULTS

We hereby show that human mesothelial cells (MC) express TLR3. After stimulation of MC with the cytokines TNF-alpha, IL-1beta and IFN-gamma alone or in combination to simulate a proinflammatory milieu as would occur during immune-mediated inflammatory disease, an upregulation of TLR3 is seen. Furthermore, a selectively TLR3 mediated, time- and dose-dependent upregulation of MMP-9 and TIMP-1 is found, whereas MMP-2 expression is not significantly affected by TLR3 stimulation.

CONCLUSIONS

With these results we provide evidence for a mechanism by which infectious agents can mediate processes of the final common path of inflammation as fibrosis via regulation of MMP and TIMP.

The role of matrix metalloproteinases in intestinal epithelial wound healing during normal and inflammatory states

BACKGROUND

Healing of the epithelium is a key consideration in gastrointestinal surgery. Inflammation is one factor innate to patients with inflammatory bowel disease that poses a risk of delayed healing of the intestinal epithelium postoperatively.

MATERIALS AND METHODS

Epithelial wounding model was performed on rat intestinal epithelial cells grown under control and interferon gamma (IFN-γ)-, interleukin-1beta (IL-1β)-, and tumor necrosis factor-alpha (TNF-α)-stimulated conditions. Wounds were measured and percent healing was calculated at 0, 8 and 24 h. Western blot analysis was performed using matrix metalloproteinase (MMP)-7 primary antibody and semiquantitative densitometry was conducted.

RESULTS

Wounds were 50.0% and 99.7% healed under control conditions at 8 and 24 h, respectively. IL-1β and IFN-γ delayed wound closure. MMP-7 increased by 2.3-fold at 8 h and 1.6-fold at 24 h during wound healing. Activated MMP-7 increased by 3- to 5-fold at 24 h. IL-1β stimulation increased levels of MMP-7 by 17% to 37% above the elevated expression due to healing alone. TNF-α up-regulated MMP-7 in non-wounded and wounded cells, and IFN-γ did not affect its expression. When MMP-7 activity was blocked, wound closure was delayed.

CONCLUSIONS

MMP-7 significantly contributes to intestinal epithelial wound closure evidenced by: (1) presence of increased MMP-7 during healing under control conditions and (2) the delayed rate of closure when MMP-7 activity was blocked. IL-1β increased MMP-7 levels beyond those seen during normal healing. It appears that some increase in MMP-7 is necessary for normal wound closure; however, its overexpression may delay intestinal epithelial wound healing, especially when MMP-7 is up-regulated by cytokines present in the inflammatory environment of inflammatory bowel disease (IBD).

Zinc deficiency impairs wound healing of colon anastomosis in rats

BACKGROUND

Anastomotic leakage is a relevant surgical complication. The aim of the study was to investigate the influence of a controlled preoperative zinc deficiency on the extracellular matrix composition of colon anastomosis.

MATERIALS AND METHODS

Forty male Wistar rats were randomized to either a zinc deficiency group (n = 20) or a control group (n = 20). In each animal, a transverse colonic end-to-end anastomosis was performed. On postoperative day 7, the surface of the mucosal villi, expression of matrix metalloproteinases (MMP) 2, 8, 9, and 13, and both the number of proliferating cells (Ki67) and apoptotic cells, as well as the collagen types I/III ratio were analyzed. Within the anastomotic area the mesenterial region and the antimesenterial region were analyzed separately.

RESULTS

In each group, one anastomotic leakage was detected. Expression of both MMP 2, 9, and 13 was significantly higher, and expression of Ki67 was significantly reduced in the zinc deficient group both mesenterial and antimesenterial. The collagen types I/III ratio was reduced in the zinc deficiency group by trend, without statistical significance neither mesenterial nor antimesenterial. Likewise, zinc deficiency affected neither the expression of MMP 8 nor the rate of apoptotic cells, respectively. Analyses of the surface of the mucosal villi revealed no significant differences comparing the groups with neither mesenterial nor antimesenterial.

CONCLUSIONS

Our study constitutes the known negative effect of zinc deficiency on wound healing. Zinc deficiency significantly increased the activity of MMPs (2, 9, and 13), caused a reduced collagen type I/III ratio, and delayed cell proliferation and quality of intestinal wound healing.

Guanylyl cyclase C prevents colon cancer metastasis by regulating tumor epithelial cell matrix metalloproteinase-9

Matrix metalloproteinase-9 (MMP-9) produced by colorectal cancer cells is a critical determinant of metastatic disease progression and an attractive target for antimetastatic strategies to reduce colon cancer mortality. Cellular signaling by cyclic GMP (cGMP) regulates MMP-9 dynamics in various cell systems, and the bacterial enterotoxin receptor guanylyl cyclase C (GCC), the principle source of cGMP in colonocytes, which is overexpressed in colorectal cancers, inhibits tumor initiation and progression in the intestine. Here, we show that ligand-dependent GCC signaling through cGMP induces functional remodeling of cancer cell MMP-9 reflected by a compartmental redistribution of this gelatinase, in which intracellular retention resulted in reciprocal extracellular depletion. Functional remodeling of MMP-9 by GCC signaling reduced the ability of colon cancer cells to degrade matrix components, organize the actin cytoskeleton to form locomotory organelles and spread, and hematogenously seed distant organs. Of significance, GCC effects on cancer cell MMP-9 prevented establishment of metastatic colonies by colorectal cancer cells in the mouse peritoneum in vivo. Because endogenous hormones for GCC are uniformly deficient in intestinal tumors, reactivation of dormant GCC signaling with exogenous administration of GCC agonists may represent a specific intervention to target MMP-9 functions in colon cancer cells. The notion that GCC-mediated regulation of cancer cell MMP-9 disrupts metastasis, in turn, underscores the unexplored utility of GCC hormone replacement therapy in the chemoprevention of colorectal cancer progression.

Tissue inhibitor of metalloproteinase-1 moderates airway re-epithelialization by regulating matrilysin activity

Obliterative bronchiolitis (OB) is the histopathological finding in chronic lung allograft rejection. Mounting evidence suggests that epithelial damage drives the development of airway fibrosis in OB. Tissue inhibitor of metalloproteinase (TIMP)-1 expression increases in lung allografts and is associated with the onset of allograft rejection. Furthermore, in a mouse model of OB, airway obliteration is reduced in TIMP-1-deficient mice. Matrilysin (matrix metallproteinase-7) is essential for airway epithelial repair and is required for the re-epithelialization of airway wounds by facilitating cell migration; therefore, the goal of this study was to determine whether TIMP-1 inhibits re-epithelialization through matrilysin. We found that TIMP-1 and matrilysin co-localized in the epithelium of human lungs with OB and both co-localized and co-immunoprecipitated in wounded primary airway epithelial cultures. TIMP-1-deficient cultures migrated faster, and epithelial cells spread to a greater extent compared with wild-type cultures. TIMP-1 also inhibited matrilysin-mediated cell migration and spreading in vitro. In vivo, TIMP-1 deficiency enhanced airway re-epithelialization after naphthalene injury. Furthermore, TIMP-1 and matrilysin co-localized in airway epithelial cells adjacent to the wound edge. Our data demonstrate that TIMP-1 interacts with matrix metalloproteinases and regulates matrilysin activity during airway epithelial repair. Furthermore, we speculate that TIMP-1 overexpression restricts airway re-epithelialization by inhibiting matrilysin activity, contributing to a stereotypic injury response that promotes airway fibrosis via bronchiole airway epithelial damage and obliteration.

Matrix metalloproteinases and diabetic foot ulcers: the ratio of MMP-1 to TIMP-1 is a predictor of wound healing

AIMS

Matrix metalloproteinases (MMPs) play a major role in wound healing: they can degrade all components of the extracellular matrix. In diabetic foot ulcers there is an excess of MMPs and a decrease of the tissue inhibitors of MMPs (TIMPs). This imbalance is probably one cause of impaired healing. However, little is known about changes in MMPs during wound healing.

METHODS

Sixteen patients with neuropathic diabetic foot ulcers participated. Wound fluid was collected regularly during the 12-week follow-up period, for measurement of MMP-1, MMP-2, MMP-8, MMP-9 and TIMP-1. Results were analysed by the degree of wound healing: good healers (defined by a reduction of at least 82% in initial wound surface at 4 weeks) and poor healers (reduction of less than 82% in wound surface at 4 weeks).

RESULTS

In good healers, levels of MMP-8 and -9 secreted by inflammatory cells decreased earlier. The initial levels of MMP-1 were similar in good and poor healers (P = 0.1) but rose significantly at week 2 in good healers (P = 0.039). There was a significant correlation between a high ratio of MMP-1/TIMP-1 and good healing (r = 0.65, P = 0.008). Receiver Operator Curve (ROC) analysis showed that an MMP-1/TIMP-1 ratio of 0.39 best predicted wound healing (sensitivity = 71%, specificity = 87.5%).

CONCLUSIONS

A high level of MMP-1 seems essential to wound healing, while an excess of MMP-8 and -9 is deleterious, and could be a target for new topical treatments. The MMP-1/TIMP-1 ratio is a predictor of wound healing in diabetic foot ulcers.

Anastomotic leakage, the search for a reliable biomarker. A review of the literature

BACKGROUND

Colorectal anastomotic leakage (AL) is a severe complication leading to severe infection, sepsis and sometimes death. At present the diagnosis is made clinically, usually at 6-8 days after surgery. An objective biomarker reflecting the intra-abdominal milieu surrounding the anastomosis would be a useful additional diagnostic tool to make the diagnosis of AL before its clinical presentation. This review aims to assess the current status of the search for such a biomarker in peritoneal fluid.

METHOD

A literature search was carried out, using MEDLINE, PubMed and the Cochrane library, for all publications concerning human peritoneal fluid in relation to postoperative complications in general, and, more specific, anastomotic leakage after colorectal surgery.

RESULTS

Analysis of several immune parameters, tissue repair parameters, parameters for ischaemia and microbiological composition of peritoneal fluid show that these can be determined reliably in the fluid, albeit with a large variance. Furthermore the data show that changes in concentration of these parameters precede AL and other postoperative complications by several days.

CONCLUSION

The results of the review demonstrate that it is possible to distinguish between patients with and without AL by measuring biomarkers in fluid from the peritoneal drain. Prospective studies with larger numbers of patients should, however, be performed and additional biomarkers should be studied to explore the full diagnostic potential of this approach.

Tumor epithelial cell matrix metalloproteinase 9 is a target for antimetastatic therapy in colorectal cancer

BACKGROUND

The current paradigm suggests that matrix metalloproteinase 9 (MMP-9) expressed by stromal cells is a therapeutic target in human colorectal tumors which presumably regulates metastatic disease progression. Conversely, whereas cancer cells within those tumors may induce stromal cells to produce MMP-9 and may be targets for MMP-9 activity, they are not the source of MMP-9 underlying metastasis.

METHODS

MMP-9 expression in matched colorectal tumors and normal adjacent mucosa from patients and human colon cancer cell lines was examined by real-time reverse transcription-PCR, laser capture microdissection, immunoelectron microscopy, and immunoblot analysis. The role of colon cancer cell MMP-9 in processes underlying metastasis was explored in vitro by examining degradation of extracellular matrix components by gelatin zymography and formation of locomotory organelles by cell spreading analysis and in vivo by quantifying hematogenous tumor cell seeding of mouse lungs.

RESULTS

Primary colorectal tumors overexpress MMP-9 compared with matched normal adjacent mucosa. In contrast to the current paradigm, MMP-9 is expressed equally by cancer and stromal cells within human colon tumors. Cancer cell MMP-9 regulates metastatic behavior in vitro, including degradation of extracellular matrix components and formation of locomotory organelles. Moreover, this MMP-9 critically regulates hematogenous seeding of mouse lungs by human colon cancer cells in vivo.

CONCLUSIONS

These observations reveal that MMP-9 produced by human colon cancer, rather than stromal, cells is central to processes underlying metastasis. They underscore the previously unrecognized potential of specifically targeting tumor cell MMP-9 in interventional strategies to reduce mortality from metastatic colorectal cancer.

Lymphatic Endothelial Cells, Lymphangiogenesis, and Extracellular Matrix

Exciting studies involving the molecular regulation of lymphangiogenesis in lymphatic-associated disorders (e.g., wound healing, lymphedema and tumor metastasis) have focused renewed attention on the intrinsic relationship between lymphatic endothelial cells (LECs) and extracellular matrix (ECM) microenvironment. ECM molecules and remodeling events play a key role in regulating lymphangiogenesis, and the "functionality"-relating molecules, especially hyaluronan, integrins, reelin, IL-7, and matrix metalloproteinases, provide the most fundamental and critical prerequisite for LEC growth, migration, tube formation, and survival, although lymphangiogenesis is directly or/and indirectly controlled by VEGF-C/-D/VEGFR- 3- Prox-1-, Syk/SLP76-, podoplanin/Ang-2/Nrp-2-, FOXC2-, and other signaling pathways in embryonic and pathological processes. New knowledge regarding the differentiation of initial lymphatics should enable improvements in understanding of a variety of cytokines, chemokines, and other factors. The lymphatic colocalization with histochemical staining by using the novel molecular markers (e.g., LYVE-1), along with subsequent injection technique with ferritin or some tracer, will reveal functional and structural features of newly formed and preexisting lymphatics. Growing recognition of the multiple functions of ECM and LEC molecules for important physiological and pathological events may be helpful in identifying the crucial changes in tissues subjected to lymph circulation and ultimately in the search for rational therapeutic approaches to prevent lymphatic-associated disorders.

Impact of elective resection on plasma TIMP-1 levels in patients with colon cancer

OBJECTIVE

Pre- and post-operative plasma tissue inhibitor of metalloproteinases-1 (TIMP-1) levels have a prognostic impact on patients with colorectal cancer. However, the surgical trauma may play an essential role in regulation of plasma TIMP-1 levels, which in turn may influence subsequent TIMP-1 measurements.

PATIENTS AND METHODS

Consecutively, 48 patients with colon cancer (CC) and 12 patients with nonmalignant colonic disease were randomised to undergo elective laparoscopically assisted or open resection followed by fast track recovery. Plasma samples were collected just before and 1, 2 and 6 h after skin incision, and 1, 2, 8 and 30 days after surgery. TIMP-1 was determined concurrently in all samples by a validated ELISA method.

RESULTS

Geometric mean preoperative TIMP-1 level was 142 ng/ml (range 54-559 ng/ml) among CC patients compared with 106 ng/ml (range 64-167 ng/ml) among patients with nonmalignant diseases (P<0.0001). TIMP-1 levels were decreased significantly 2 h after skin incision compared to the preoperative levels returning to preoperative levels at 6 h. A highly significant (P<0.0001) maximum level was observed 1 day after surgery and was decreasing to preoperative levels 30 days after surgery. Patients undergoing laparoscopically assisted or open resection had similar TIMP-1 levels at each time point.

CONCLUSIONS

Major surgery has considerable impact on plasma TIMP-1 levels. Intra- and post-operative changes of plasma TIMP-1 levels are independent of the surgical approach, and resection for CC does not lead to a significant decrease of plasma TIMP-1 levels within 30 days postoperatively.

Changes in gelatinase activity in the gastrointestinal tract after anastomotic construction in the ileum or colon

PURPOSE

The strength of the uninjured and anastomosed intestinal wall is determined by its submucosal connective tissue. Matrix degradation by matrix metalloproteinases may result in loss of strength. It is known that anastomotic construction leads to up-regulation of matrix metalloproteinase activity in the wound area, but no quantitative data are available as to the extent of this effect throughout the intestinal wall. This study was designed to quantitate changes in gelatinolytic activity in the intestine after anastomotic construction in the ileum or colon.

METHODS

An anastomosis was constructed in the distal ileum or distal colon of rats, and animals were killed after one or three days. Tissue samples (5 mm) were collected containing the suture line, its adjacent segments (2- x 5-mm in both directions) and at nine other, more distant, sites throughout the gastrointestinal tract. Similar samples were collected from nonoperated control rats. All samples were analyzed by quantitative gelatin zymography.

RESULTS

In control rats, the most prominent gelatinolytic activities were found at 80 kDa, thought to represent a nonspecific proteolytic activity, 60 kDa and 50 kDa, representing the proform and active form of matrix metalloproteinase-2, respectively. Activities were higher in the small bowel than in the large bowel. Anastomotic construction led to massive up-regulation of an activity at 105 kDa, and its dimer, believed to represent promatrix metalloproteinase-9. Matrix metalloproteinase-2 remained unaffected, whereas the activity of the 80 kDa protein was significantly (P < 0.05) reduced. Significantly increased matrix metalloproteinase-9 activity was found in the actual anastomotic segments and in the immediately adjacent tissue. Matrix metalloproteinase-9 activities in the anastomotic segments were highest at Day 1 in the ileum and at Day 3 in the colon. Anastomotic construction in the ileum or colon did not lead to any significant changes of any gelatinolytic activity at the more distant sites in the bowel wall.

CONCLUSIONS

Up-regulation of gelatinase activity after anastomotic construction in the intestine is caused by matrix metalloproteinase-9. Because the effect is local and not systemic, unwanted matrix degradation at distant sites seems unlikely.

Regulation of fibrogenic/fibrolytic genes by platelet-derived growth factor C, a novel growth factor, in human dermal fibroblasts

Platelet-derived growth factor (PDGF) is a potent mitogenic and chemotactic cytokine, and PDGF-C is a novel growth factor belonging to the PDGF family. In this study, to determine whether this growth factor can contribute to fibrosis and tissue remodeling, we examined the effect of PDGF-CC on the expression of fibrogenic/fibrolytic genes such as type I collagen, fibronectin (FN), matrix metalloproteinases (MMPs), and their inhibitors (TIMPs) in normal human dermal fibroblasts in vitro. PDGF elevated the levels of MMP-1 or TIMP-1 protein as well as mRNA, whereas this cytokine had no influence on the expression of type I collagen, FN, or TIMP-2. PDGF-CC also increased the levels of MMP-1 catalytic activity in the cultured media and mRNA expression, which was paralleled that on the levels of promoter activation. Additionally, PDGF-CC induced the mitogenic and migratory activity of human dermal fibroblasts in a dose-dependent manner. On the other hand, we also determined the specificity of the inhibitory effect of monoclonal antibodies against PDGF-CC generated by immunizing balb/c mice with recombinant human PDGF-CC. This antibody could inhibit the regulatory effects of MMP-1 or TIMP-1 synthesis as well as the mitogenic effects on human dermal fibroblasts induced by PDGF-CC, whereas this antibody did not affect those induced by other PDGF forms such as PDGF-AA, -AB, or -BB. These results suggest that this cytokine plays a role in the tissue remodeling.

Inhibition by the soluble syndecan-1 ectodomains delays wound repair in mice overexpressing syndecan-1

Wound repair is a tightly regulated process stimulated by proteases, growth factors, and chemokines, which are modulated by heparan sulfate. To characterize further the role of the heparan sulfate proteoglycan syndecan-1 in wound repair, we generated mice overexpressing syndecan-1 (Snd/Snd) and studied dermal wound repair. Wound closure, reepithelialization, granulation tissue formation, and remodeling were delayed in Snd/Snd mice. Soluble syndecan-1 was increased, and shedding was prolonged in wounds from Snd/Snd mice. Excess syndecan-1 increased the elastolytic activity of wound fluids. Additionally, cells in the granulation tissue and keratinocytes at wound edges showed markedly reduced proliferation rates in Snd/Snd mice. Skin grafting experiments between Snd/Snd and control mice indicated that the slower growth rate was mainly due to a soluble factor in the Snd/Snd mouse skin. Syndecan-1 immunodepletion and further degradation experiments identified syndecan-1 ectodomain as a dominant negative inhibitor of cell proliferation. These studies indicate that shed syndecan-1 ectodomain may enhance proteolytic activity and inhibit cell proliferation during wound repair.