Hyaluronic acid induces tumour necrosis factor-alpha production by human macrophages in vitro

Biomaterials and tissue engineering approaches using glycosaminoglycans for tissue repair: Lessons learned from the native extracellular matrix

Glycosaminoglycans (GAGs) are an important component of the extracellular matrix as they influence cell behavior and have been sought for tissue regeneration, biomaterials, and drug delivery applications. GAGs are known to interact with growth factors and other bioactive molecules and impact tissue mechanics. This review provides an overview of native GAGs, their structure, and properties, specifically their interaction with proteins, their effect on cell behavior, and their mechanical role in the ECM. GAGs' function in the extracellular environment is still being understood however, promising studies have led to the development of medical devices and therapies. Native GAGs, including hyaluronic acid, chondroitin sulfate, and heparin, have been widely explored in tissue engineering and biomaterial approaches for tissue repair or replacement. This review focuses on orthopaedic and wound healing applications. The use of GAGs in these applications have had significant advances leading to clinical use. Promising studies using GAG mimetics and future directions are also discussed. STATEMENT OF SIGNIFICANCE: Glycosaminoglycans (GAGs) are an important component of the native extracellular matrix and have shown promise in medical devices and therapies. This review emphasizes the structure and properties of native GAGs, their role in the ECM providing biochemical and mechanical cues that influence cell behavior, and their use in tissue regeneration and biomaterial approaches for orthopaedic and wound healing applications.

The effect of normal, metaplastic, and neoplastic esophageal extracellular matrix upon macrophage activation

Introduction

Macrophages are capable of extreme plasticity and their activation state has been strongly associated with solid tumor growth progression and regression. Although the macrophage response to extracellular matrix (ECM) isolated from normal tissue is reasonably well understood, there is a relative dearth of information regarding their response to ECM isolated from chronically inflamed tissues, pre-neoplastic tissues, and neoplastic tissues. Esophageal adenocarcinoma (EAC) is a type of neoplasia driven by chronic inflammation in the distal esophagus, and the length of the esophagus provides the opportunity to investigate macrophage behavior in the presence of ECM isolated from a range of disease states within the same organ.

Methods

Normal, metaplastic, and neoplastic ECM hydrogels were prepared from decellularized EAC tissue. The hydrogels were evaluated for their nanofibrous structure (SEM), biochemical profile (targeted and global proteomics), and direct effect upon macrophage (THP-1 cell) activation state (qPCR, ELISA, immunolabeling) and indirect effect upon epithelial cell (Het-1A) migration (Boyden chamber).

Results

Nanofibrous ECM hydrogels from the three tissue types could be formed, and normal and neoplastic ECM showed distinctive protein profiles by targeted and global mass spectroscopy. ECM proteins functionally related to cancer and tumorigenesis were identified in the neoplastic esophageal ECM including collagen alpha-1(VIII) chain (COL8A1), lumican, and elastin. Metaplastic and neoplastic esophageal ECM induce distinctive effects upon THP-1 macrophage signaling compared to normal esophageal ECM. These effects include activation of pro-inflammatory IFNγ and TNFα gene expression and anti-inflammatory IL1RN gene expression. Most notably, neoplastic ECM robustly increased macrophage TNFα protein expression. The secretome of macrophages pre-treated with metaplastic and neoplastic ECM increases the migration of normal esophageal epithelial cells, similar behavior to that shown by tumor cells. Metaplastic ECM shows similar but less pronounced effects than neoplastic ECM suggesting the abnormal signals also exist within the pre-cancerous state.

Conclusion

A progressively diseased ECM, as exists within the esophagus exposed to chronic gastric reflux, can provide insights into novel biomarkers of early disease and identify potential therapeutic targets.

Hyaluronan in wound healing: rediscovering a major player

Wound healing involves a series of carefully modulated steps, from initial injury and blood clot to the final reconstituted tissue or scar. A dynamic reciprocity exists throughout between the wound, blood elements, extracellular matrix, and cells that participate in healing. Multiple cytokines and signal transduction pathways regulate these reactions. A major component throughout most of the process is hyaluronan, a straight-chain carbohydrate extracellular matrix polymer. Hyaluronan occurs in multiple forms, chain length being the only distinguishing characteristic between them. Levels of hyaluronan in its high-molecular-weight form are prominent in the earliest stages of wound repair. Progressively more fragmented forms occur in a manner not previously appreciated. We outline here steps in the wound healing cascade in which hyaluronan participates, as well as providing a review of its metabolism. Although described by necessity in a series of quantum steps, the healing process is constituted by a smooth continuum of overlapping reactions. The prevalence of hyaluronan in the wound (initially termed "hexosamine-containing mucopolysaccharide"), particularly in its early stages, was pointed out over half a century ago by the Harvard surgeon J. Engelbert Dunphy. It appears we are now returning to where we started.

Alternative methods for assessing biocompatibility and function of implant materials

Biocompatibility testing is used to evaluate the host response to implantable materials and to assess their ability to perform in applications in which they are intended to interact with biological systems. In compliance with international and/or national standards, such assessment is based mainly on the results of experimental implantation into animal tissues. However, the development of in vitro experimental techniques creates new opportunities to observe and to understand the interaction of biomaterials with host tissue. The state-of-the-art application of alternative methods in biocompatibility testing is presented in this review article. It is discussed with respect to the Three Rs concept (reduction, refinement, replacement) of Russell & Burch. Perspectives on alternative methods in biocompatibility studies are discussed with regard to the possible role of biomaterials in tissue engineering.

Effects of lentiviral vector-mediated TRADD expression on the inhibition of hypertrophic scar formation

The tumor necrosis factor receptor-associated death domain protein (TRADD) regulates cell proliferation and apoptosis via tumor necrosis factor alpha (TNF-α)-mediated signaling pathways. Low levels of TRADD expression may result in the excessive proliferation of hypertrophic scar fibroblasts (HSFb). This study investigated the effects of a lentiviral vector carrying the human tradd gene on the proliferation, apoptosis and type I collagen synthesis of HSFb and embryonic fibroblasts (EFb) and further explored the resulting effects on hypertrophic scars (HS). We utilized cytoimmunofluorescence and Western blotting to confirm the expression of TRADD in HSFb and EFb. A PLVX-TRADD-EGFP lentivirus was prepared and transfected into EFb and HSFb, and then the expression of a TRADD-GFP-FLAG fusion protein was detected in HSFb and EFb. After stimulation with 10 ng/mL TNF-α, cell proliferation, apoptosis, and the synthesis of type I collagen were assessed. Our results show that the expression level of TRADD was significantly lower in HSFb than in EFb. A biologically active PLVX-TRADD-EGFP lentivirus was constructed and transfected into HSFb and EFb. The TRADD-GFP-FLAG fusion protein was effectively expressed in HSFb and EFb. Either alone or in combination with 10 ng/mL TNF-α, the PLVX-TRADD-EGFP lentivirus inhibited proliferation, caused a G2/M phase arrest, induced the appearance of a sub-G1 apoptotic peak and inhibited the secretion of type I collagen by HSFb without significantly affecting EFb. These results suggest that the low expression of TRADD in HSFb is a principal reason for their excessive proliferation. The transfection of a PLVX-TRADD-EGFP lentivirus led to the normal expression of TRADD in HSFb. When combined with 10 ng/mL TNF-α, a PLVX-TRADD-EGFP lentivirus transfection could inhibit cell proliferation, promote apoptosis, and reduce the secretion of type I collagen in HSFb, thereby reducing HS formation.

Hyaluronan in intestinal homeostasis and inflammation: implications for fibrosis

The causes of fibrosis, or the inappropriate wound healing, that follows chronic intestinal inflammation are not well defined and likely involve the contributions of multiple cellular mechanisms. As other articles in this series confirm, inflammatory cytokines clearly play a role in driving cell differentiation to the myofibroblast phenotype, promoting proliferation and extracellular matrix deposition that are characteristic of fibrotic tissue. However, controlling the balance of cytokines produced and process of myofibroblast differentiation appears to be more complex. This review considers ways in which hyaluronan, an extracellular matrix component that is remodeled during the progression of colitis, may provide indirect as well as direct cues that influence the balancing act of intestinal wound healing.

Prevention of intraperitoneal adhesions and abscesses by polysaccharides isolated from Phellinus spp in a rat peritonitis model

OBJECTIVE

To assess whether polysaccharides isolated from fungi, Phellinus spp, could reduce the adhesion and abscess formation in a rat peritonitis model.

SUMMARY BACKGROUND DATA

Although polysaccharides from Phellinus spp is a well-known material with antiinflammatory properties, little is known regarding its ability to prevent intraperitoneal adhesions. We have assessed the adhesion- and abscess-reducing effect of polysaccharides from Phellinus gilvus (PG) and Phellinus linteus (PL) in a rat peritonitis model.

METHODS

In 60 SD rats, experimental peritonitis was induced using the cecal ligation and puncture model (CLP). Animals were randomly assigned to 5 groups; ringer lactate solution (RL group), polysaccharides from PG and PL (PG and PL group), hyaluronic acid (HA group), and carboxymethylcellulose (CMC group). Intraperitoneal adhesions and abscesses were noted at 7 day after CLP. RT-PCR assay for urokinase-type plasminogen activator (uPA), its cellular receptor (uPAR), tissue-type plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), and tumor necrosis factor (TNF)- alpha was performed to assess the cecal tissue.

RESULTS

Adhesion formation was significantly reduced in PG, PL, CMC, and HA groups (P < 0.001) compared with that in RL group. The incidence of abscesses was also significantly reduced in PG and PL groups (P < 0.05) compared with that in the RL group. The level of uPA, uPAR, tPA, and TNF-alpha was highly expressed in PG and PL group, as compared with the RL group.

CONCLUSIONS

We concluded that PG and PL had significant adhesion- and abscess-reducing effects and may act by modulating fibrinolytic capacity of uPA and/or tPA produced from macrophages in a rat peritonitis model.

Comparison of intraperitoneal anti-adhesive polysaccharides derived from Phellinus mushrooms in a rat peritonitis model

AIM: To assess the adhesion- and abscess-reducing capacities of various concentrations of polysaccharides derived from fungus, Phellinus gilvus (PG) or Phellinus linteus (PL) in a rat peritonitis model.

METHODS: In 96 SD rats, experimental peritonitis was induced using the cecal ligation and puncture model (CLP). Rats were randomly assigned to 8 groups; Ringer’s lactate solution (RL group), hyaluronic acid (HA group), 0.025%, 0.25%, and 0.5% polysaccharides from PG (PG0.025, 0.25, and 0.5 groups), and PL (PL0.025, 0.25, and 0.5 groups). Adhesions and abscesses were noted at 7 d after CLP. RT-PCR assay was performed to assess the cecal tissue.

RESULTS: Adhesion formation was significantly reduced in PG0.25, 0.5, PL0.25, 0.5, and HA groups (2.5±0.7, 2.4±0.7, 3.8±1.0, 3.6±0.8, and 2.7±1.1, P<0.05). The incidence of abscesses was significantly reduced in all treated groups compared to RL group (58%, P<0.05). The urokinase-type plasminogen activator (uPA) gene expression was greatly up-regulated by increasing the concentration of polysaccharides. The urokinase-type plasminogen activator receptor (uPAR) and tumor necrosis factor (TNF)-α mRNA were highly expressed in PG0.25, 0.5, PL0.25, and 0.5 groups.

CONCLUSION: We concluded that 0.5% polysaccharide derived from PG and PL was the optimal concentration in preventing adhesion and abscess formation and may act by modulating activity of uPA and TNF-α in a rat peritonitis model.

Prevention of intraperitoneal adhesion formation using beta-glucan after ileocolic anastomosis in a rat bacterial peritonitis model

BACKGROUND

To investigate the effects of beta-glucan on intraabdominal abscess and adhesion formation after ileocolic anastomosis in a rat bacterial peritonitis model.

METHODS

Sixty male Wistar rats were used in this study. Bacterial peritonitis was induced by performing a cecal ligation and puncture (CLP). On the first day, abdomen was reopened and peritoneal fluid samples were taken for microbiological examination. Thereafter, cecum was resected and ileocolic anastomosis was made. Group 1 rats were given 1 mL of normal saline as a placebo. Group 2 and group 3 rats were given beta-D-glucan 2 mg/kg by intramuscularly; 1 mg of beta-1,3-D-glucanase was administered to group 3 rats just after the use of beta-D-glucan. Half of each group were killed at day 7 and at day 21, respectively. Adhesions were scored and the presence of intraabdominal abscesses was noted.

RESULTS

One day after CLP, microbiological examination showed polymicrobial bacterial peritonitis. Five (8%) of the 60 animals died owing to sepsis. One week after CLP, in two rats in each group developed abscess formation. Three weeks after CLP, abscess formation was observed in only one rat in each group. The rats treated with the beta-glucan had significantly lower adhesion scores than did the saline-treated rats (P = 0.008 at one week; P = 0.001 at 3 weeks). Administration of beta-glucanase inhibited beta-glucan activity and resulted in more adhesions (P = 0.022 at 1 week; P = 0.006 at 3 weeks).

CONCLUSIONS

Although the use of beta-glucan after ileocolic anastomosis in rats with experimentally developed intraabdominal sepsis does not have any significantly effect on mortality and abscess formation, beta-glucan is capable of reducing the frequency of adhesion. This effect of beta-glucan has been prevented with beta-glucanase

Hyaluronic acid-N-hydroxysuccinimide: a useful intermediate for bioconjugation

Hyaluronic acid (HA) is an abundant nonsulfated glycosaminoglycan component of synovial fluid and the extracellular matrix. HA is an important building block for biocompatible and biointeractive materials with applications in drug delivery, tissue engineering, wound repair, and viscosupplementation. Herein we describe the synthesis and characterization of HA-N-succinimide, an activated ester of the glucuronic acid moiety. This HA-active ester intermediate is a precursor for fluorescent probes, drug-polymer conjugates, and cross-linked hydrogels. As a demonstration, we used HA-NHS to prepare HA-BODIPY by coupling with the hydrazide derivative of the fluor. Intracellular uptake of HA-BODIPY into human ovarian cancer cells, which overexpress cell-surface HA receptors, was visualized using confocal microscopy.

Effects of hyaluronan on the invasive properties of human breast cancer cells in vitro

Hyaluronan (HA) is a high molecular weight glycosaminoglycan present mostly in the extracellular matrix (ECM). HA binds to specific receptors such as CD44. Its production is increased at the tumour-stroma interface, including those in breast cancer tumours. It has been suggested that it facilitates invasion of tumour cells into the ECM by a hydrodynamic effect, or by altering tumour cell behaviour. Using in vitro tests we studied the effect of immobilized (iHA) and soluble (sHA) HA on the invasive properties of four human breast cancer cell lines with different levels of CD44 expression. Our results show that iHA acts as an adhesive, haptotactic, and motility stimulating factor for the CD44 positive Hs578T cells and induces the expression of membrane CD44. sHA also changes the motility properties of the Hs578T and MDA-231 cells and increases their CD44 expression. sHA or iHA have no measurable effect on the adhesion, motility or CD44 expression of the ZR-75-1 and MCF-7 breast cancer cells. Our results establish that in high CD44 expressing breast cancer cells HA modulates tumour cell adhesion and motility and also increases the expression of its own receptor, CD44.

The use of ADCON-T/N glycosaminoglycan gel in the revision of tethered scars

Recurrent subdermal scar tethering is a difficult management problem in areas of high tissue mobility. We describe a novel solution to this clinical problem, which involves instilling the anti-fibrotic gel ADCON-T/N in the plane between the skin and the underlying structures. We present our results in three difficult clinical situations where excellent results have been achieved using this method.

Proinflammatory cytokines differentially regulate hyaluronan synthase isoforms in fetal and adult fibroblasts

BACKGROUND/PURPOSE

Fetal wound healing is a relatively scarless process that occurs in an hyaluronan-rich environment. Understanding the regulation of hyaluronan expression may provide insight into the process of fetal repair. Therefore, the purpose of this study was to compare the regulation of hyaluronan and hyaluronan synthase transcripts by the proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in human adult and fetal fibroblasts.

METHODS

Hyaluronan deposited in the medium of untreated fibroblasts or fibroblasts treated with either IL-1beta or TNF-alpha was determined by an assay utilizing iodine I 125-hyaluronan binding protein. HAS transcript levels were compared in using a ribonuclease protection assay.

RESULTS

IL-1beta induced an increase in hyaluronan accumulation by both fetal and adult fibroblasts. In contrast, TNF-alpha induced higher levels of hyaluronan only in fetal fibroblasts. HAS-2 and HAS-3 transcript levels were constitutively expressed by both fetal and adult fibroblasts. Proinflammatory cytokines induced a differential increase in HAS-1 and HAS-3 transcript levels.

CONCLUSIONS

Differential regulation was observed in hyaluronan accumulation and for HAS transcript levels in fetal and adult dermal fibroblasts. The muted response of fetal fibroblasts to cytokines may be relevant to the minimal inflammation associated with fetal repair.

Alginate dressings in surgery and wound management: Part 3

This final article in the series looks at the functioning of seaweed-derived dressings at a cellular level, as well as the importance of choosing appropriate secondary dressings