Effect of intra-articular injection of a hyaluronic acid-alendronate conjugate on post-traumatic osteoarthritis induced by destabilization of the medial meniscus in rats.

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by pain and cartilage damage. Intra-articular (i.a) viscosupplementation with hyaluronic acid (HA) is frequently used for the management of OA. Preclinical studies have reported that bisphosphonates (BPs) may have a therapeutic potential to slow down or reverse the progression of OA. Among these, alendronate (ALN) has demonstrated chondroprotective effects in both in vitro and vivo experiments. This study evaluated the effects of a novel alendronate-hyaluronic acid (ALN-HA) conjugate on an OA in vivo model induced by medial meniscus destabilization (DMM). DMM surgery was performed on the knees of Sprague Dawley rats that received, after four weeks, one intra-articular (i.a.) injection of: (1) ALN-HA; (2) HA; (3) sodium chloride (NaCl). Sham-operated rats were used as control. Allodynia was assessed by Von Frey test. Joint degeneration was evaluated eight weeks after treatment by micro-computed tomography (micro-CT), histology, and immunohistochemistry. Collagen cross-linked C-telopeptides (CTX-I and CTX-II) serum levels were determined by ELISA. Paw withdrawal threshold increased in ALN-HA group when compared to rats treated with NaCl or HA. Micro-CT did not show differences between ALN-HA, HA and NaCl groups. ALN-HA injection produced significant improvements in articular cartilage degeneration showing an OARSI score lower than those of HA and NaCl, and reduced matrix metalloproteinase (MMP)-13, MMP-3, interleukin-6, vascular endothelial growth factor and Caspase-3 expression. CTX-I was reduced after ALN-HA treatment when compared to NaCl. Our results indicate that i.a. use of ALN after conjugation with HA limits OA development and progression in the rat DMM model, and may lead to the development of novel therapeutic strategies in OA management.

A Photopolymerizable Biocompatible Hyaluronic Acid Hydrogel Promotes Early Articular Cartilage Repair in a Minipig Model In Vivo.

Articular cartilage defects represent an unsolved clinical challenge. Photopolymerizable hydrogels are attractive candidates supporting repair. This study investigates the short-term safety and efficacy of two novel hyaluronic acid (HA)-triethylene glycol (TEG)-coumarin hydrogels photocrosslinked in situ in a clinically relevant large animal model. It is hypothesized that HA-hydrogel-augmented microfracture (MFX) is superior to MFX in enhancing early cartilage repair, and that the molar degree of substitution and concentration of HA affects repair. Chondral full-thickness defects in the knees of adult minipigs are treated with either 1) debridement (No MFX), 2) debridement and MFX, 3) debridement, MFX, and HA hydrogel (30% molar derivatization, 30 mg mL-1 HA; F3) (MFX+F3), and 4) debridement, MFX, and HA hydrogel (40% molar derivatization, 20 mg mL-1 HA; F4) (MFX+F4). After 8 weeks postoperatively, MFX+F3 significantly improves total macroscopic and histological scores compared with all other groups without negative effects, besides significantly enhancing the individual repair parameters "defect architecture," "repair tissue surface" (compared with No MFX, MFX), and "subchondral bone" (compared with MFX). These data indicate that photopolymerizable HA hydrogels enable a favorable metastable microenvironment promoting early chondrogenesis in vivo. This work also uncovers a mechanism for effective HA-augmented cartilage repair by combining lower molar derivatization with higher concentrations.

The role of high molecular weight hyaluronic acid in mucoadhesion on an ocular surface model.

Hyaluronic acid (HA) is frequently formulated in eye drops to improve the stability of the tear film by hydration and lubrication. Mucoadhesion is related to the ocular residence time and therefore to the effectiveness of the eye drops. The ocular residence time of the HA formulation is correlated with the ability of HA to create specific strong interactions in the ocular surface with the mucus layer, mainly composed of a mixture of secreted mucins (MUC; gel forming MUC5AC and MUC2) and shed membrane-bound soluble mucins (MUC1, MUC4, and MUC16). Dry eye disease (DED) is a multifactorial pathology of the preocular tear film with possible damage to the ocular surface classified in two types: (1) aqueous-deficient dry eye and (2) evaporative dry eye, caused by a decrease in goblet cell density that reduces MUC expression and/or by meibomian gland dysfunction, that results in a drop in the lipidic fraction of the tear film. In this work, the binding affinity between HA and MUC2 has been evaluated with three complementary approaches because the secreted MUCs play a pivotal role in the viscoelastic properties of the tear film: 1. Rheological analysis, measuring the mucoadhesive index and the complex viscosity in relation to MM (Molecular Mass) and concentration; 2. Fluorescence analysis, using a fluorescent hydrophobic probe, to investigate the conformational change of MUC2 during the interaction with the HA polymer; 3. Surface plasmon resonance analysis, used to measure the affinity between MUC2 (immobilized on the surface of a sensor chip) and the HA polymers that flowed on it at the molecular level. For all these tests, the mucoadhesive performance of the natural HA linearly increases with the MM, whereas cross-linked HA and other emollient and gelling agents (formulated in artificial tears) do not show the same mucoadhesive properties (with the exception of xanthan gum). The mucoadhesive performance of high MM HA has also been confirmed in conditions that simulate the pathological condition of the tear film during DED by decreasing the MUC2 or oleic acid concentration. Physico-chemical analysis of a series of marketed artificial tears confirms the linear correlation between the MM of the HA used in the products and the mucoadhesive index measured on the ocular surface model.

Amphiphilic peptide-based MMP3 inhibitors for intra-articular treatment of knee OA.

Since 2007, Metalloproteases (MMPs) have been considered potential targets for treating osteoarthritis (OA), for which the primary pathogenic event is the extensive degeneration of articular cartilage. MMP3 is an enzyme critical for these degenerative changes. However, problems of selectivity, low bioavailability and poor metabolic profile during clinical trials of MMPs inhibitors (MMPIs) led to limited beneficial effect and thus did not justify further pursuit of the clinical studies. In a previous work, a new alkyl derivative of hyaluronic acid (HA), HYADD4®, previously approved as intra-articular treatment for knee OA, was studied in vitro and in vivo as MMP3I. Molecular simulation studies confirmed the interaction between the alkyl side chain of this HA derivative and the additional S1' pocket of MMP3. However, the high MW and the polar HA backbone of HYADD4® imply a high desolvation energy cost, which can potentially decrease its inhibitory potency. In this study, a new class of MMP3Is based on a small peptide backbone (CGV) chemically derivatized with an alkyl chain was developed through interactive cycles of design, synthesis and screening, accompanied by computational evaluation and optimization. Two MMP3Is, e(I) and l(II), were selected because of their effective inhibitory activity (3.2 and 10.2 µM, respectively) and water solubility. Both MMPIs showed a broad range of inhibitory effects against almost all the MMPs tested. In an in vitro model of inflammatory OA, e(I) was the most effective MMPI: at the concentration of 93 µM, it reversed inflammatory outcomes. Moreover, because of its amphiphilic structure, the e(I) MMPI promoted stable micellar formulation at concentrations higher than 0.2 mg/mL in water. The findings were confirmed by TEM and Nile red staining analysis. Based on these results, the e(I) MMPI can be considered a good candidate for the intra-articular treatment of OA, and the micellar formulation of this peptide in an aqueous buffer can potentially increase the bioavailability and, thus, the efficacy of the MMPIs.

A versatile and robust analytical method for hyaluronan quantification in crosslinked products and complex matrices.

Hyaluronic acid (HA), a naturally occurring biopolymer composed of repeating units of d-glucuronic acid and N-acetyl-glucosamine, is widely used as principal component of drugs, medical devices, nutraceuticals and cosmetics. Chemical modifications of HA or the presence of unmodified HA in complex matrices often brings common analytical techniques to fail its identification or quantification. In this work, a specific method for the quantification of HA and HA derivatives was developed and tested. After strong acid hydrolysis, polysaccharide depolymerization and N-acetylglucosamine deacetylation, quantitatively yielded glucosamine residues were derivatized using Fluorenylmethyloxycarbonyl chloride (FMOC), separated and quantitated by means of HPLC equipped with UV detection. The method was partially validated according to ICH Q2(R1) and successfully applied on different viscosupplements composed by modified HA or medical devices containing unmodified HA in complex matrices.

The action of hyaluronan in functional properties, morphology and expression of matrix effectors in mammary cancer cells depends on its molecular size.

Breast cancer constitutes a heterogeneous disease. The expression profiles of estrogen receptors (ERs), as well as the expression patterns of extracellular matrix (ECM) macromolecules, determine its development and progression. Hyaluronan (HA) is an ECM molecule that regulates breast cancer cells' properties in a molecular size-dependent way. Previous studies have shown that 200-kDa HA fragments modulate the functional properties, morphology, and expression of several matrix mediators of the highly metastatic ERα- /ERß+ MDA-MB-231 cells. In order to evaluate the effects of HA fragments (< 10, 30 and 200-kDa) in ERß-suppressed breast cancer cells, the shERß MDA-MB-231 cells were used. These cells are less aggressive when compared with MDA-MB-231 cells. To this end, the functional properties, the morphology, and the expression of the molecules associated with breast cancer cells metastatic potential were studied. Notably, both cell proliferation and invasion were significantly reduced after treatment with 200-kDa HA. Moreover, as assessed by scanning electron microscopy, 200-kDa HA affected cellular morphology, and as assessed by qPCR, upregulated the epithelial marker Ε-cadherin. The expression profiles of ECM mediators, such as HAS2, CD44, and MMP7, were also altered. On the other hand, cellular migration and the expression levels of syndecan-4 (SDC-4) were not significantly affected in contrast to our observations regarding MDA-MB-231 cells. These novel data demonstrate that the molecular size of the HA determines its effects on ERß-suppressed breast cancer cells and that 200-kDa HA exhibits antiproliferative effects on these cells. A deeper understanding of this mechanism may contribute to the development of therapeutic strategies against breast cancer.

Hyaluronic acid-alendronate conjugate: A macromolecular drug delivery system for intra-articular treatment of osteoarthritis.

Objective: Osteoarthritis (OA) is a painful degenerative disease of the whole joint structure, including articular cartilage, synovial fluid, and subchondral bone. Hyaluronic acid (HA), an anionic non-sulfated glycosaminoglycan, is commonly used for intra-articular (IA) treatment in OA, while bisphosphonates (BPs) are anti-resorptive drugs that act on the bone. Here, a novel conjugate with a covalent and hydrolysable linker between HA and alendronate (ALD) was designed as an attractive therapeutic strategy for IA drug delivery. Design: The HA-ALD derivative was synthesized and tested in comparison with a simple mixture of HA and ALD for in vitro ALD release, rheological properties, cytotoxicity towards osteoblasts and chondrocytes and in an in vitro efficacy assay of OA inflammatory model on bovine cartilage explants. Results: The structure of HA-ALD was elucidated exhibiting no depolymerization and efficient drug incorporation. The controlled ALD release in vitro was slower compared to the simple mixture of HA and ALD; moreover, the derivative showed calcium-tuned rheological properties. The absence of cytotoxicity towards osteoblasts and chondrocytes was shown for up to 7 days, and the viability of chondrocytes was confirmed by fluorescence microscopy. Finally, a reduction in collagen release and MMP-13 expression was measured in the OA inflammatory model. Conclusion: This new HA-ALD derivative opens the door to a new approach for OA treatment, as it combines viscosupplementation and biological effects of HA with the pharmacological activity of BPs. Prolonged ALD release increased rheological properties and beneficial effect against cartilage degradation make it a promising IA therapy for OA.

HA-based dermal filler: downstream process comparison, impurity quantitation by validated HPLC-MS analysis, and in vivo residence time study.

The success of hyaluronic acid (HA)-based dermal fillers, with more than 2 million minimally invasive procedures conducted in 2016 in the US alone, is due to their hygroscopic properties of biocompatibility and reversibility. The type and density of HA cross-linkage, as well as the manufacturing technology, may influence not only the in vivo persistence but also the safety profile of dermal fillers. 1,4-Butanediol diglycidyl ether (BDDE) is the cross-linker used in most market-leading HA fillers; 1,4-butanediol di-(propan-2,3-diolyl) ether (BDPE) is the major impurity obtained from the HA-BDDE cross-linking (HBC) process. In this work, a new process to obtain high purity HBC fillers was developed. A new HPLC-MS method was validated for the quantification of BDPE content in HBC dermal fillers. In vitro cytotoxicity of BDPE was evaluated in fibroblasts (IC50 = 0.48 mg/mL). The viscoelasticity was monitored during the shelf-life of the HBC-10% hydrogel and was correlated with in vitro hyaluronidase resistance and in vivo residence time in a rabbit model. This analysis showed that elasticity is the best parameter to predict the in vivo residence time. Finally, a series of parameters were investigated in certain marketed dermal fillers and were compared with the results of the HBC-10% hydrogel.

Photocrosslinked hydrogels from coumarin derivatives of hyaluronic acid for tissue engineering applications.

Hydrogels are an increasingly attractive choice in the fields of regenerative medicine, wound care and tissue engineering as important forms of bio-scaffolds. For many clinical needs, injectable in situ crosslinkable hydrogels are strongly preferred, due to treatment effectiveness and ease of use. In this study, hyaluronic acid (HA), containing side-arms linked to photo-active coumarin moieties, was used for the preparation of wall-to-wall hydrogels. This photocrosslinkable HA, hereafter called HA-TEG-coumarin, produces colourless aqueous solutions that solidify upon near-UV irradiation (at a specific wavelength of 365 nm) via a clean [2 + 2] photocycloaddition reaction, without by-products formation. The crosslinking event, a robust and non-cytotoxic process, does not require catalysts or radical initiators: in the field of hyaluronan photocrosslinking, this innovative feature is significant to ensure the whole biocompatibility and to avoid collateral reactions. Mechanical and rheological tests showed that hyaluronan derivatives became hydrogels after 3-5 min of irradiation, with average values for bulk and surface elastic moduli of about 32 kPa and 193 kPa, respectively. Fluorescence recovery after photobleaching (FRAP) assay showed that the hydrogels are porous and allow a good permeation for nutrients and growth factors. Cell metabolism and proliferation assays revealed that hydrogel-encapsulated fibroblasts maintained their viability and that HA-TEG-coumarin sustained the proliferation of non-adherent myoblasts. For all of these reasons and thanks to a safe free-radical approach, this novel hyaluronan coumarin derivative could be a good candidate for tissue engineering and regenerative medicine applications.

Molecular size-dependent specificity of hyaluronan on functional properties, morphology and matrix composition of mammary cancer cells.

High levels of hyaluronan (ΗΑ), a major extracellular matrix (ECM) glycosaminoglycan, have been correlated with poor clinical outcome in several malignancies, including breast cancer. The high and low molecular weight HΑ forms exert diverse biological functions. Depending on their molecular size, ΗΑ forms either promote or attenuate signaling cascades that regulate cancer progression. In order to evaluate the effects of different ΗΑ forms on breast cancer cells' behavior, ΗΑ fragments of defined molecular size were synthesized. Breast cancer cells of different estrogen receptor (ER) status - the low metastatic, ERα-positive MCF-7 epithelial cells and the highly aggressive, ERß-positive MDA-MB-231 mesenchymal cells - were evaluated following treatment with HA fragments. Scanning electron microscopy revealed that HA fragments critically affect the morphology of breast cancer cells in a molecular-size dependent mode. Moreover, the ΗΑ fragments affect cell functional properties, the expression of major ECM mediators and epithelial-to-mesenchymal transition (ΕΜΤ) markers. Notably, treatment with 200 kDa ΗΑ increased the expression levels of the epithelial marker Ε-cadherin and reduced the expression levels of HA synthase 2 and mesenchymal markers, like fibronectin and snail2/slug. These novel data suggest that the effects of HA in breast cancer cells depend on the molecular size and the ER status. An in-depth understanding on the mechanistic basis of these effects may contribute on the development of novel therapeutic strategies for the pharmacological targeting of aggressive breast cancer.

A new potential spreading factor: Streptomyces koganeiensis hyaluronidase. A comparative study with bovine testes hyaluronidase and recombinant human hyaluronidase of the HA degradation in ECM.

BACKGROUND: Recombinant human hyaluronidase has been used in the interstitial matrix to promote the dispersion of therapeutics. The production and isolation of an extracellular hyaluronidase from Streptomyces koganeiensis (rHyal_Sk) has recently been described. METHODS: The specificity of rHyal_Sk has been assessed against heparan sulfate, chondroitin sulfates and sulfated HAs. The oligomers generated by HA degradation have been investigated by MALDI-TOF MS analysis. rHyal_Sk has been compared with BTH and PH20 in vitro, against cross-linked HA (ACP) and HA-aggrecan complex, and in vivo, by means of a diffusion assay in nude mice. RESULTS: Depolymerization of HA by rHyal_Sk gave tetra-, hexa- and octasaccharides in high yields. The reaction mechanism and the high HA specificity were demonstrated. The in vivo diffusion assay, supported by the in vitro tests, evidenced an initially enhanced enzymatic activity of rHyal_Sk compared to BTH and PH20. CONCLUSIONS: rHyal_Sk, compared to BTH and PH20, showed higher substrate specificity and no inhibition from GAGs sulfate, together with a superior performance for HA depolymerization in ECM. As better predictive tests for the in vivo activity of hyaluronidase we developed two assays based on the degradation of ACP or of the HA-aggrecan complex. GENERAL SIGNIFICANCE: rHyal_Sk is a new potential spreading factor for intradermal drug administration. Hyaluronidases of distinct classes, that show equivalent activities in a common turbidimetric assay, could have different potencies and dose-efficacies in vivo which influences the therapeutic effect. The new proposed in vitro tests are designed to obtain a predictive characterization of the enzyme activity in vivo.