Structurally different RGTAs modulate collagen-type expression by cultured aortic smooth muscle cells via different pathways involving fibroblast growth factor-2 or transforming growth factor-beta1

ReGeneraTing Agents (rgta®) technology combined with antibiotics improves outcomes for infections in the upper limb

A matrix therapy agent marketed as CACIPLIQ20® showed marked improvement in the healing rate of hand infections, including functional recovery. It can be used at both earlier and later stages to promote faster healing and prevent an adverse outcome.

Microenvironmental support for cell delivery to the inner ear

Transplantation of mesenchymal stromal cells (MSC) presents a promising approach not only for the replacement of lost or degenerated cells in diseased organs but also for local drug delivery. It can potentially be used to enhance the safety and efficacy of inner ear surgeries such as cochlear implantation. Options for enhancing the effects of MSC therapy include modulating cell behaviour with customized bio-matrixes or modulating their behaviour by ex vivo transfection of the cells with a variety of genes. In this study, we demonstrate that MSC delivered to the inner ear of guinea pigs or to decellularized cochleae preferentially bind to areas of high heparin concentration. This presents an opportunity for modulating cell behaviour ex vivo. We evaluated the effect of carboxymethylglucose sulfate (Cacicol^®), a heparan sulfate analogue on spiral ganglion cells and MSC and demonstrated support of neuronal survival and support of stem cell proliferation.

Engineering Tissues without the Use of a Synthetic Scaffold: A Twenty-Year History of the Self-Assembly Method

Twenty years ago, Dr. François A. Auger, the founder of the Laboratory of Experimental Organogenesis (LOEX), introduced the self-assembly technique. This innovative technique relies on the ability of dermal fibroblasts to produce and assemble their own extracellular matrix, differing from all other tissue-engineering techniques that use preformed synthetic scaffolds. Nevertheless, the use of the self-assembly technique was limited for a long time due to its main drawbacks: time and cost. Recent scientific breakthroughs have addressed these limitations. New protocol modifications that aim at increasing the rate of extracellular matrix formation have been proposed to reduce the production costs and laboratory handling time of engineered tissues. Moreover, the introduction of vascularization strategies in vitro permits the formation of capillary-like networks within reconstructed tissues. These optimization strategies enable the large-scale production of inexpensive native-like substitutes using the self-assembly technique. These substitutes can be used to reconstruct three-dimensional models free of exogenous materials for clinical and fundamental applications.

Matrix regeneration agents improve wound healing in non-stressed human corneal epithelial cells

PurposeMatrix regenerating agents (RGTAs) emerged as promising in vivo wound-healing agents. These agents could prove beneficial for the treatment of dry eye disease-associated corneal micro-erosions; therefore, we aimed to evaluate the wound healing efficacy of regenerative agents (RGTAs or serum) in an in vitro model of hyperosmolarity (HO) stressed and non-stressed human corneal epithelial cells.Patients and methodsThe migration and proliferation induced by the regenerative agents was evaluated using an in vitro scratch wound assay and brome-deoxy-uridine incorporation. The inflammatory profile and effects of osmoregulators were also investigated. The two-tailed paired t-test calculated the statistical significance, with P-value<0.05 considered significant.ResultsThe most efficient inducer of re-epithelization was 2% serum, followed closely by 2% RGTA with an average improvement in cell migration of 1.8- and 1.4-fold, respectively, when compared with the non-treated control. Hyperosmolar stress significantly reduced the restorative effects of both serum and RGTAs; these effects were, however, neutralized by the osmoregulator betaine.ConclusionThese findings suggest that RGTAs could provide efficient treatment for dry-eye associated corneal micro-lesions if ocular surface HO is neutralized.

Matrix-Based Regenerating Agent for Corneal Wound Healing After Collagen Cross-Linking

PURPOSE

Corneal collagen cross-linking (CXL) is associated with massive cellular damage, the long-term clinical consequences of which have still to be elucidated. In this study, we seek to determine whether matrix-based regenerating agent (RGTA) therapy has a positive influence on stromal regeneration after CXL.

METHODS

Twelve New Zealand white rabbits were randomly divided into 2 groups of 6. CXL of the right cornea was performed in both groups, followed by topical corneal application of one drop of vehicle or one drop of RGTA. In vivo confocal laser-scanning microscopy was used to monitor corneal changes over time. At the end of the experiment, 2 weeks postoperatively, the corneas were excised and processed for histology.

RESULTS

Epithelial healing was noted in both groups 3 days after CXL. One week after treatment, in vivo confocal laser-scanning microscopy in both groups revealed a significantly thicker acellular stromal zone in the vehicle group compared with the RGTA group (P = 0.0165). This difference persisted up to 2 weeks postoperatively, when acellular zone thickness was 96 ± 10 µm in the RGTA group and 146 ± 34 µm in the vehicle group (P = 0.0058). These findings were confirmed by histology, which also revealed earlier cell repopulation in the RGTA group.

CONCLUSIONS

The anterior stroma of cross-linked corneas exhibited cell loss after CXL. Cell repopulation in the anterior corneal stroma occurred earlier when CXL was followed by topical RGTA treatment. Further studies are required to examine the impact of this ophthalmic RGTA on corneal nerve regeneration after CXL.

Synergistic effect of regenerating agent plus cord blood serum eye drops for the treatment of resistant neurotrophic keratitis: a case report and a hypothesis for pathophysiologic mechanism

This report describes a case of a 72-year-old Caucasian woman presenting with a large neurotrophic keratitis with a large persistent epithelial defect, with a longest linear diameter of 7 mm and greatest perpendicular width of 5 mm, affecting epithelium, Bowman membrane, and anterior stroma. Corneal disease was resistant to conventional treatment and classified as stage 2 according to Mackie classification. Patient was instructed to instill regenerating agent (RGTA) eye drops in the morning, as the first eye drop, once every 5 days in combination with daily cord blood serum (CBS) eye drops 6 times/day. The patient was asked to visit after 1 week (V1), 2 weeks (V2), 3 weeks (V3), and 4 weeks (V4) of study treatment. In V4 treatment, corneal sensitivity improved, and keratitis healed with resolution of stromal inflammation. Global treatment tolerance was very satisfactory. Patient continued the therapy for a further month after complete healing. Currently, the patient has been followed up for 3 months without any sign of keratitis recurrence. To the best of our knowledge, this case report describes for the first time the successful combined use of RGTA and CBS eye drops for the treatment of neurotrophic keratitis resistant to conventional treatment. We hypothesize that RGTA eye drops could provide an optimal migration substrate and that growth factors supplied by CBS eye drops could strengthen the repair process by promoting cell growth over the matrix. Combined RGTA and CBS eye drop therapy could be a new potential option for the successful treatment of resistant neurotrophic keratitis, particularly when each drug alone is not effective.

Role of seaweed laminaran from Saccharina longicruris on matrix deposition during dermal tissue-engineered production

Our laboratory has developed a technique to reconstruct in vitro tissue from human cells using the self-assembly tissue-engineering method, which utilizes the ability of fibroblasts to deposit the matrix they secrete. The time necessary for tissue construction, several weeks, is a drawback for many clinical uses. We hypothesized that the addition of laminaran can increase the deposition of matrix, speeding up the production of the tissue. Laminaran was isolated from the brown seaweed Saccharina longicruris harvested in Canada and its structure was evaluated. Laminaran is a small molecular weight polysaccharide composed of linear glucose chains. Monolayer-cultured human skin fibroblasts were cultured in the presence of laminaran with ascorbate for 7 or 35 days to produce a dermis. Treatment did not induce any variation in the growth rate or alpha smooth muscle actin content but it did increase the deposition of collagen I in a dose-dependent manner. After 35 days, the reconstructed dermal thickness was increased when laminaran was added, and collagen I deposition and MMP activity were also significantly increased. Thus, laminaran can be used to increase the rate of production of reconstructed self-assembled dermis and can also potentially be used in cosmetic or therapeutic creams to stimulate matrix production.

Stewart-Bluefarb syndrome: review of the literature and case report of chronic ulcer treatment with heparan sulphate (Cacipliq20®)

Stewart-Bluefarb syndrome (SBS), also known as acroangiodermatitis or pseudo-Kaposi, is a condition rarely encountered. It involves skin lesions that are clinically similar to Kaposi sarcoma but are histologically different, and are usually secondary to an underlying arteriovenous fistula. Treatment of this disease usually involves the correction of the underlying vascular abnormality, with the mainstay of therapy ranging from compression devices for venous stasis, limited oral medications (dapsone and erythromycin) and local wound care including topical steroids. Different methods of treatment showed varied success but none is ideal. We report a case of a lower extremity ulcer in a 22-year-old male recently diagnosed with SBS successfully treated with heparan sulphate (Cacipliq20®).

Angiogenic growth factors interactome and drug discovery: The contribution of surface plasmon resonance

Angiogenesis is implicated in several pathological conditions, including cancer, and in regenerative processes, including the formation of collateral blood vessels after stroke. Physiological angiogenesis is the outcome of a fine balance between the action of angiogenic growth factors (AGFs) and anti-angiogenic molecules, while pathological angiogenesis occurs when this balance is pushed toward AGFs. AGFs interact with multiple endothelial cell (EC) surface receptors inducing cell proliferation, migration and proteases upregulation. On the contrary, free or extracellular matrix-associated molecules inhibit angiogenesis by sequestering AGFs (thus hampering EC stimulation) or by interacting with specific EC receptors inducing apoptosis or decreasing responsiveness to AGFs. Thus, angiogenesis results from an intricate network of interactions among pro- and anti-angiogenic molecules, EC receptors and various modulators. All these interactions represent targets for the development of pro- or anti-angiogenic therapies. These aims call for suitable technologies to study the countless interactions occurring during neovascularization. Surface plasmon resonance (SPR) is a label-free optical technique to study biomolecular interactions in real time. It has become the golden standard technology for interaction analysis in biomedical research, including angiogenesis. From a survey of the literature it emerges that SPR has already contributed substantially to the better understanding of the neovascularization process, laying the basis for the decoding of the angiogenesis "interactome" and the identification of "hub molecules" that may represent preferential targets for an efficacious modulation of angiogenesis. Here, the still unexploited full potential of SPR is enlightened, pointing to improvements in its use for a deeper understanding of the mechanisms of neovascularization and the identification of novel anti-angiogenic drugs.

Refractory sickle cell leg ulcer: is heparan sulphate a new hope?

Patients with sickle cell disease are known to have recurrent lower extremity ulcers that have a high pain score and are resistant to conventional means of wound therapy. This study reports the successful use of synthetic heparan sulphate (Cacipliq20(®) , OTR3, Paris, France) in the treatment of a sickle cell ulcer that had failed to respond to several other means of treatment. Therapeutic success was assessed by complete wound coverage and vast improvement in pain score. This is the first study to report use of heparan sulphate in sickle cell ulcers.

Glycosaminoglycan mimetic associated to human mesenchymal stem cell-based scaffolds inhibit ectopic bone formation, but induce angiogenesis in vivo

Tissue engineering approaches to stimulate bone formation currently combine bioactive scaffolds with osteocompetent human mesenchymal stem cells (hMSC). Moreover, osteogenic and angiogenic factors are required to promote differentiation and survival of hMSC through improved vascularization through the damaged extracellular matrix (ECM). Glycosaminoglycans (GAGs) are ECM compounds acting as modulators of heparin-binding protein activities during bone development and regenerative processes. GAG mimetics have been proposed as ECM stabilizers and were previously described for their positive effects on bone formation and angiogenesis after local treatment. Here, we developed a strategy associating the GAG mimetic [OTR4120] with bone substitutes to optimize stem cell-based therapeutic products. We showed that [OTR4120] was able to potentiate proliferation, migration, and osteogenic differentiation of hMSC in vitro. Its link to tricalcium phosphate/hydroxyapatite scaffolds improved their colonization by hMSC. Surprisingly, when these combinations were tested in an ectopic model of bone formation in immunodeficient mice, the GAG mimetics inhibit bone formation induced by hMSC and promoted an osteoclastic activity. Moreover, the inflammatory response was modulated, and the peri-implant vascularization stimulated. All together, these findings further support the ability of GAG mimetics to organize the local ECM to coordinate the host response toward the implanted biomaterial, and to inhibit the abnormal bone formation process on a subcutaneous ectopic site.

Heparin mimetics

Explorations of the therapeutic potential of heparin mimetics, anionic compounds that are analogues of glycosaminoglycans (GAGs), have gone hand-in-hand with the emergence of understanding as to the role of GAGs in many essential biological processes. A myriad of structurally different heparin mimetics have been prepared and examined in many diverse applications. They range in complexity from heterogeneous polysaccharides that have been chemically sulphated to well-defined compounds, designed in part to mimic the natural ligand, but with binding specificity and potency increased by conjugation to non-carbohydrate pharmacophores. The maturity of the field is illustrated by the seven heparin mimetics that have achieved marketing approval and there are several more in late-stage clinical development. An overview of the structural determinants of heparin mimetics is presented together with an indication of their activities. The challenges in developing heparin mimetics as drugs, specificity and potential toxicity issues, are highlighted. Finally, the development path of three structurally very different mimetics, PI-88(®), GMI-1070 and RGTAs, each of which is in clinical trials, is described.

[Management of herpes zoster neurotrophic ulcer using a new matrix therapy agent (RGTA): A case report]

Neurotrophic keratopathy is a potential consequence of herpes simplex virus (HSV) or varicella zoster virus (VZV) infection. The treatment is based on artificial tears and the withdrawal of preserved eye drops or other types of epitheliotoxic topical medicines. Autologous serum or amniotic membrane transplantation may also be used in severe cases, but their cost and safety are still under debate. We report a case of a patient with a history of herpes zoster ophthalmicus, who developed a persistent epithelial ulcer after cataract surgery, with no improvement despite 3 weeks of artificial tears (eight drops per day). A new ophthalmologic solution based on a regenerating agent (RGTA, Cacicol20(®)) was then used, with a dosage of two eye drops per week for 6 weeks. Improvement was observed 1 week later, and complete healing was obtained in less than 3 weeks, with no side effects. This heparin mimetic, which may stimulate extracellular matrix healing, may be a possible alternative therapy to autologous serum or amniotic membrane transplantation in severe neurotrophic ulcer. However, randomized studies are necessary to validate this observation.

Regenerating matrix-based therapy for chronic wound healing: a prospective within-subject pilot study

The aim of this study was to determine whether a skin-specific bioengineered regenerating agent (RGTA) heparan sulphate mimetic (CACIPLIQ20) improves chronic wound healing. The design of this article is a prospective within-subject study. The setting was an urban hospital. Patients were 16 African-American individuals (mean age 42 years) with 22 wounds (mean duration 2.5 years) because of either pressure, diabetic, vascular or burn wounds. Two participants each were lost to follow-up or removed because of poor compliance, resulting in 18 wounds analysed. Sterile gauze was soaked with CACIPLIQ20 saline solution, placed on the wound for 5 min, then removed twice weekly for 4 weeks. Wounds were otherwise treated according to the standard of care. Twenty-two percent of wounds fully healed during the treatment period. Wounds showed a 15.2-18.1% decrease in wound size as measured by the vision engineering research group (VERG) digital wound measurement system and total PUSH scores, respectively, at 4 weeks (P = 0.014 and P = 0.003). At 8 weeks there was an 18-26% reduction in wound size (P = 0.04) in the remaining patients. Wound-related pain measured by the visual analogue pain scale and the wound pain scale declined 60% (P = 0.024) and 70% (P = 0.001), respectively. Patient and clinician satisfaction remained positive throughout the treatment period. It is concluded that treatment with CACIPLIQ20 significantly improved wound-related pain and may facilitate wound healing. Patient and clinician satisfaction remained high throughout the trial.

Multidistrict human mesenchymal vascular cells: pluripotency and stemness characteristics

BACKGROUND AIMS

The presence of ectopic tissues in the pathologic artery wall raises the issue of whether multipotent stem cells may reside in the vasculature itself. Recently mesenchymal stromal cells (MSC) have been isolated from different human vascular segments (VW MSC), belying the previous view that the vessel wall is a relatively quiescent tissue.

METHODS

Resident multipotent cells were recovered from fresh arterial segments (aortic arches, thoracic and femoral arteries) collected in a tissue-banking facility and used to establish an in situ and in vitro study of the stemness features and multipotency of these multidistrict MSC populations.

RESULTS

Notch-1+, Stro-1+, Sca-1+ and Oct-4+ cells were distributed along an arterial wall vasculogenic niche. Multidistrict VW MSC homogeneously expressed markers of stemness (Stro-1, Notch-1 and Oct-4) and MSC lineages (CD44, CD90, CD105, CD73, CD29 and CD166) whilst they were negative for hematopoietic and endothelial markers (CD34, CD45, CD31 and vWF). Each VW MSC population had characteristics of stem cells, i.e. a high efflux capability for Hoechst 33342 dye and the ability to form spheroids when grown in suspension and generate colonies when seeded at low density. Again, VW MSC cultured in induction media exhibited adipogenic, chondrogenic and leiomyogenic potential but less propensity to osteogenic differentiation, as documented by histochemical, immunohistochemical, molecular and electron microscopy analysis.

CONCLUSIONS

Overall, these findings may enlighten the physiopathologic mechanisms of vascular wall diseases as well as having potential implications for cellular, genetic and tissue engineering approaches to treating vascular pathologies when these are unresponsive to medical and surgical therapies.

Glycosaminoglycan mimetics trigger IP3-dependent intracellular calcium release in myoblasts

Glycosaminoglycans (GAG) are sulfated polysaccharides that play an important role in regulating cell functions. GAG mimetics called RGTAs (for ReGeneraTing Agents) have been shown to stimulate tissue repair. In particular they accelerate myogenesis, in part via their heparin-mimetic property towards growth factors. RGTAs also increase activity of calcium-dependent intracellular protease suggesting an effect on calcium cellular homeostasis. This effect was presently investigated on myoblasts in vitro using one member of the RGTA family molecule named OTR4120. We have shown that OTR4120 or heparin induced transient increases of intracellular calcium concentration ([Ca(2+)]i) in pre-fusing myoblasts from both mouse SolD7 cell line and rat skeletal muscle satellite cells grown in primary culture by mobilising sarcoplasmic reticulum store. This [Ca(2+)]i was not mediated by ryanodine receptors but instead resulted from stimulation of the Inositol-3 phosphate-phospholipase C activation pathway. OTR4120-induced calcium transient was not mediated through an ATP, nor a tyrosine kinase, nor an acetylcholine receptor but principally through serotonin 5-HT2A receptor. This original finding shows that the GAG mimetic can induce calcium signal through serotonin receptors and the IP3 pathway may be relevant to its ability to favour myoblast differentiation. It supports a novel and unexpected function of GAGs in the regulation of calcium homeostasis.

Matrix therapy in regenerative medicine, a new approach to chronic wound healing

Nonhealing wounds remain a major health problem whose treatment is challenging and costly. Treatments based on cells or growth factors are still not very effective. We developed an entirely novel strategy consisting in treatment of the wound-tissue matrix with biopolymers engineered to mimic heparan sulfates called OTR4120. This compound was dextran polymer with sulfated and carboxymethyl groupments. After binding to matrix proteins, the heparan-sulfate-mimicking polymer protects the microenvironment, maintaining the normal production of signals and growth factors needed for healing to occur. Here, we show that a specific biopolymer accelerates ulcer closure and improves re-epithelialization and dermal-matrix-component remodeling. OTR4120 treatment was associated with faster maturation of epidermal structures, most notably regarding the number of epithelial-cell layers, and with an appearance that more closely resembled normal skin. Treatment had also a main effect on collagen I and III expression. Necrotic skin ulcers induced in mice with doxorubicin recovered normal collagen levels and organization, with no evidence of fibrosis. Thus, appropriate polymer-based matrix therapy is a valid and simple alternative to regenerative medicine.

Glycosaminoglycan mimetics inhibit SDF-1/CXCL12-mediated migration and invasion of human hepatoma cells

We have recently reported that the CXC-chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 induces proliferation, migration, and invasion of the Huh7 human hepatoma cells through its G-protein-coupled receptor CXCR4 and that glycosaminoglycans (GAGs) are involved in these events. Here, we demonstrate by surface plasmon resonance that the chemokine binds to GAG mimetics obtained by grafting carboxylate, sulfate or acetate groups onto a dextran backbone. We also demonstrate that chemically modified dextrans inhibit SDF-1/CXCL12-mediated in vitro chemotaxis and anchorage-independent cell growth in a dose-dependent manner. The binding of GAG mimetics to the chemokine and their effects in modulating the SDF-1/CXCL12 biological activities are mainly related to the presence of sulfate groups. Furthermore, the mRNA expression of enzymes involved in heparan sulfate biosynthesis, such as exostosin-1 and -2 or N-deacetylase N-sulfotransferases remained unchanged, but heparanase mRNA and protein expressions in Huh7 cells were decreased upon GAG mimetic treatment. Moreover, decreasing heparanase-1 mRNA levels by RNA interference significantly reduced SDF-1/CXCL12-induced extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation. Therefore, we suggest that GAG mimetic effects on SDF-1/CXCL12-mediated hepatoma cell chemotaxis may rely on decreased heparanase expression, which impairs SDF-1/CXCL12's signaling. Altogether, these data suggest that GAG mimetics may compete with cellular heparan sulfate chains for the binding to SDF-1/CXCL12 and may affect heparanase expression, leading to reduced SDF-1/CXCL12 mediated in vitro chemotaxis and growth of hepatoma cells.

Significant reduction in neural adhesions after administration of the regenerating agent OTR4120, a synthetic glycosaminoglycan mimetic, after peripheral nerve injury in rats

OBJECT

Extradural and intraneural scar formation after peripheral nerve injury frequently causes tethering and compression of the nerve as well as inhibition of axonal regeneration. Regenerating agents (RGTAs) mimic stabilizing and protective properties of sulphated glycosaminoglycan toward heparin-binding growth factors. The aim of this study was to assess the effect of an RGTA known as OTR4120 on extraneural fibrosis and axonal regeneration after crush injury in a rat sciatic nerve model.

METHODS

Thirty-two female Wistar rats underwent a standardized crush injury of the sciatic nerve. The animals were randomly allocated to RGTA treatment or sham treatment in a blinded design. To score neural adhesions, the force required to break the adhesions between the nerve and its surrounding tissue was measured 6 weeks after nerve crush injury. To assess axonal regeneration, magnetoneurographic measurements were performed after 5 weeks. Static footprint analysis was performed preoperatively and at Days 1, 7, 14, 17, 21, 24, 28, 35, and 42 postoperatively.

RESULTS

The magnetoneurographic data show no significant difference in conduction capacity between the RGTA and the control group. In addition, results of the static footprint analysis demonstrate no improved or accelerated recovery pattern. However, the mean pullout force of the RGTA group (67 +/- 9 g [mean +/- standard error of the mean]) was significantly (p < 0.001) lower than that of the control group (207 +/- 14 g [mean +/- standard error of the mean]).

CONCLUSIONS

The RGTAs strongly reduce nerve adherence to surrounding tissue after nerve crush injury.

RGTA OTR 4120, a heparan sulfate proteoglycan mimetic, increases wound breaking strength and vasodilatory capability in healing rat full-thickness excisional wounds

ReGeneraTing Agents (RGTAs), a family of polymers engineered to protect and stabilize heparin-binding growth factors, have been shown to promote tissue repair and regeneration. In this study, the effects of one of these polymers, RGTA OTR4120, on healing of full-thickness excisional wounds in rats were investigated. Two 1.5 cm diameter circular full-thickness excisional wounds were created on the dorsum of a rat. After creation of the wounds, RGTA OTR4120 was applied. The progress of healing was assessed quantitatively by evaluating the wound closure rate, vasodilatory capability, and wound breaking strength. The results showed a triple increase of the local vascular response to heat provocation in the RGTA OTR4120-treated wounds as compared with vehicle-treated wounds. On days 14 and 79 after surgery, the wounds treated with RGTA OTR4120 gained skin strength 12% and 48% of the unwounded skin, respectively, and displayed a significantly increased gain in skin strength when compared with control animals. These results raise the possibility of efficacy of RGTA OTR4120 in accelerating surgically cutaneous wound healing by enhancing the wound breaking strength and improving the microcirculation.

Glycosaminoglycans and their synthetic mimetics inhibit RANTES-induced migration and invasion of human hepatoma cells

The CC-chemokine regulated on activation, normal T-cell expressed, and presumably secreted (RANTES)/CCL5 mediates its biological activities through activation of G protein-coupled receptors, CCR1, CCR3, or CCR5, and binds to glycosaminoglycans. This study was undertaken to investigate whether this chemokine is involved in hepatoma cell migration or invasion and to modulate these effects in vitro by the use of glycosaminoglycan mimetics. We show that the human hepatoma Huh7 and Hep3B cells express RANTES/CCL5 G protein-coupled receptor CCR1 but not CCR3 nor CCR5. RANTES/CCL5 binding to these cells depends on CCR1 and glycosaminoglycans. Moreover, RANTES/CCL5 strongly stimulates the migration and the invasion of Huh7 cells and to a lesser extent that of Hep3B cells. RANTES/CCL5 also stimulates the tyrosine phosphorylation of focal adhesion kinase and activates matrix metalloproteinase-9 in Huh7 hepatoma cells, resulting in increased invasion of these cells. The fact that RANTES/CCL5-induced migration and invasion of Huh7 cells are both strongly inhibited by anti-CCR1 antibodies and heparin, as well as by beta-d-xyloside treatment of the cells, suggests that CCR1 and glycosaminoglycans are involved in these events. We then show by surface plasmon resonance that synthetic glycosaminoglycan mimetics, OTR4120 or OTR4131, directly bind to RANTES/CCL5. The preincubation of the chemokine with each of these mimetics strongly inhibited RANTES-induced migration and invasion of Huh7 cells. Therefore, targeting the RANTES-glycosaminoglycan interaction could be a new therapeutic approach for human hepatocellular carcinoma.

TGF-β1: a novel target for cardiovascular pharmacology

Transforming growth factor beta-1 (TGF-beta1) plays a key role in cardiovascular disease by a process which allows the loss of its protective properties. The first therapeutic attempt to restore its function by selectively designed novel drugs are being made. In addition, it has been recognized that the TGF-beta1 pathway is involved in the vascular mechanism of action of some current clinical drugs, such as acetylsalicylic acid, thiazolidinediones and statins. The aim of this paper is to review the possible value of TGF-beta1 as both a disease marker and a therapeutical target for cardiovascular disease.

RGTA OTR4120, a heparan sulfate mimetic, is a possible long-term active agent to heal burned skin

Burn-related skin fibrosis leads to loss of tissue function and hypertrophic scar formation with damaging consequences for the patient. There is therefore a great need for an efficient agent to treat burned skin. We report that ReGeneraTing Agent (RGTA) reduces burn-induced skin alteration. The tissue-regenerating effect of RGTA OTR4120 was evaluated after 1-6 days and after 10 months in a rat skin burn model. This effect was also examined in vitro using fibroblasts isolated from control and 6-day-old burned skins. We measured production of dermal collagen I, III, and V and activities of metalloproteinases 2 and 9 (MMP-2 and MMP-9). Ratio of collagen III over collagen I production increased 6 days after the burn, because of a decrease in collagen I production. After 10 months, ratio of collagen III over collagen I in burn sites was still increased compared with control skin, because of an increase in collagen III production. Both abnormalities were corrected by OTR4120. OTR4120 increased pro- and active MMP-2 and MMP-9, compared with healthy and burned controls and therefore accelerated remodeling. Similar data were obtained with cultured fibroblasts from healthy and burned skins. OTR4120 enhanced healing in short- and long-term after burns, reducing the formation of fibrotic tissue, and then represents a potential agent to improve burned skin healing.

Polysaccharide microarrays for polysaccharide-platelet-derived-growth-factor interaction studies

Polysaccharide microarrays have great potential for the high-throughput analysis of polysaccharide-protein interactions. Here we demonstrate that a polysaccharide microarray prepared by printing a library of dextran polymers derivatized by methylcarboxylate, benzylamide, and sulfate groups (DMCBSu compounds) on to glass slides permitted the rapid identification of a set of compounds able to interact with the platelet-derived growth factor BB (PDGF-BB) isoform, a growth factor involved in wound healing. Microarray interaction results were compared to the capacity of DMCBSu compounds to potentiate the in vitro PDGF-BB-induced proliferation of human dermal fibroblasts.

Les agents de régénération (ou RGTAs) : une nouvelle approche thérapeutique

RGTAs, or ReGeneraTing Agents constitute a new class of medicinal substance that enhance both speed and quality of tissue healing and leading in some case to a real tissue regenerating process. RGTAs consist of chemically engineered polymers adapted to interact with and protect against proteolytic degradation of cellular signaling proteins known as growth factors, cytokines, interleukins, colony stimulating factors, chemokines, neurotrophic factors etc. Indeed almost all these proteins of cellular communication are naturally stored in the extra cellular matrix interacting specifically with the heparan sulfates or HS. After tissue injury of any cause, cells die liberating glycanases and proteases inducing first HS degradation then liberation of the cytokines which in turn are susceptible to degradation as they are no longer protected. By replacing the natural HS, RGTAs will protect cytokines from proteolyses as they are liberated from the matrix compartment matter in the wound. This spatio-temporal selective protection of cytokines results in a preservation of the natural endogenous signaling of a tissue and is reflected by spectacular tissue regeneration or by a very greatly improved tissue repair. These observations indicate that mammals have an unexpected ability to regenerate and that RGTA helps to reveal this capacity. The aim of OTR3 is to develop RGTA into a drug to treat specific tissue lesions.

Periodontitis destructions are restored by synthetic glycosaminoglycan mimetic

Periodontitis are bacterium-driven inflammatory diseases that destroy tooth-supporting tissues whose complete restoration is not currently possible. RGTA, a new class of agents, have this capacity in an animal model. Periodontitis was induced in hamsters and, starting 8 weeks later, injected RG1503, a glycosaminoglycan synthesized from a 40 kDa dextran behaving like a heparan sulfate mimetic (1.5 mg kg(-1) w(-1)) or saline for 8 weeks. The three periodontium compartments were evaluated by immunohistochemistry and morphometry. The gingival extracellular matrix disorganized by inflammation was restoring under treatment. The collagen network was repaired and resumed its previous organization. Fibrillin-1 expression was restored so that the elastic network rebuilt at a distance from the pocket and began to reconstruct near the pocket. Apoptotic cell numbers were decreased in the pocket epithelium, and more so in the infiltrated connective tissue. The continuity and the thickness of the basement membrane were restored and testified normalization of epithelium connective tissue interaction. The amount of alveolar bone increased around the first molar, and the interradicular bone was rebuilt. The root cementum was thickened and the number of proliferating cells in the periodontal ligament was increased close to the cementum. RG1503 treatment induces potent anabolic reactions in the extracellular matrices of the different tissues of the periodontium and recruitment of progenitors. In particular, the cell proliferation close to the root surface suggests the reformation of a functional attachment apparatus. These results demonstrate that RG1503 reverses the degenerative changes induced by inflammation and favors the conditions of a regenerative process. Thus, RGTA, a known matrix component mimetic and protector, may be considered as a new therapeutic tool to regenerate the tissues destroyed by periodontitis.

A synthetic glycosaminoglycan mimetic binds vascular endothelial growth factor and modulates angiogenesis

In a previous study, we showed that in situ injection of glycosaminoglycan mimetics called RGTAs (ReGeneraTing Agents) enhanced neovascularization after skeletal muscular ischemia (Desgranges, P., Barbaud, C., Caruelle, J. P., Barritault, D., and Gautron, J. (1999) FASEB J. 13, 761-766). In the present study, we showed that the RGTA OTR4120 modulated angiogenesis in the chicken embryo chorioallantoic membrane assay, in a dose-dependent manner. We therefore investigated the effect of OTR4120 on one of the most specific angiogenesis-regulating heparin-binding growth factors, vascular endothelial growth factor 165 (VEGF165). OTR4120 showed high affinity binding to VEGF165 (Kd = 2.2 nm), as compared with heparin (Kd = 15 nm), and potentiated the affinity of VEGF165 for VEGF receptor-1 and -2 and for neuropilin-1. In vitro, OTR4120 potentiated VEGF165-induced proliferation and migration of human umbilical vein endothelial cells. In the in vivo Matrigel plug angiogenesis assay, OTR4120 in a concentration as low as 3 ng/ml caused a 6-fold increase in VEGF165-induced angiogenesis. Immunohistochemical staining showed a larger number of well differentiated VEGFR-2-expressing-cells in Matrigel sections of OTR4120-treated plug than in control sections. These findings indicate that OTR4120 enhances the VEGF165-induced angiogenesis and therefore may hold promise for treating disorders characterized by deficient angiogenesis.

Immunization with a tetramer derivative of an anti-inflammatory pentapeptide produced by Entamoeba histolytica protects gerbils (Meriones unguiculatus) against experimental amoebic abscess of the liver

Axenically grown Entamoeba histolytica produces a pentapeptide (Met-Gln-Cys-Asn-Ser) with several anti-inflammatory properties, including the inhibition of human monocyte locomotion (Monocyte Locomotion Inhibitory Factor (MLIF)). A construct displays the same effects as the native material. It remains to be seen if MLIF is used, or even produced in vivo by the tissue-invading parasite. If MLIF were to be relevant in invasive amoebiasis, immunizing against it could diminish this parasite advantage and prevent lesions. KLH-linked MLIF mixed with Freund's adjuvant was too aggressive an immunizing material to answer this question. However, immunization with a tetramer of MLIF (but not a scrambled version of MLIF) around a lysine core (MLIF-MAPS), that displays increased antigenicity, yet lacks excessive innate immunity activation, completely protects gerbils against amoebic abscess of the liver caused by the intraportal injection of virulent E. histolytica. Liver abscesses caused by Listeria monocytogenes were not prevented. Invasive E. histolytica may produce the parent protein of MLIF in vivo, and if appropriately cleaved, it may play a role in invasive amoebiasis. MLIF may join new vaccination strategies against amoebiasis.

Regulation and role of transforming growth factor-beta in immune tolerance induction and inflammation

Transforming growth factor-beta (TGF-beta) is known to mediate pleiotropic functions both inside and outside the immune system. Recent progress in this field underlines the role of TGF-beta in regulatory T (Treg) cells, where it participates in both suppression and differentiation. In addition, recent information highlights the role of TGF-beta in repair responses that lead to matrix deposition and tissue remodelling. Many chronic inflammatory diseases, such as asthma, profit from the suppression of specific immune responses by TGF-beta; however, TGF-beta-mediated tissue remodelling can be a serious complication in such diseases.

Survey of the year 2004 commercial optical biosensor literature

The year 2004 represents a milestone for the biosensor research community: in this year, over 1000 articles were published describing experiments performed using commercially available systems. The 1038 papers we found represent an approximately 10% increase over the past year and demonstrate that the implementation of biosensors continues to expand at a healthy pace. We evaluated the data presented in each paper and compiled a 'top 10' list. These 10 articles, which we recommend every biosensor user reads, describe well-performed kinetic, equilibrium and qualitative/screening studies, provide comparisons between binding parameters obtained from different biosensor users, as well as from biosensor- and solution-based interaction analyses, and summarize the cutting-edge applications of the technology. We also re-iterate some of the experimental pitfalls that lead to sub-optimal data and over-interpreted results. We are hopeful that the biosensor community, by applying the hints we outline, will obtain data on a par with that presented in the 10 spotlighted articles. This will ensure that the scientific community at large can be confident in the data we report from optical biosensors.