Search Results (34)

This study presents a detailed Raman spectroscopic investigation of hydrogels composed of sodium hyaluronate and two N-terminally blocked dipeptides: N-acetyl-L-alanine-methyl-amide (NAcAlaNHMA) and N-acetyl-L-tyrosine-methyl-amide (NAcTyrNHMA). Vibrational spectra of the dipeptides in both crystalline and aqueous forms were analyzed and supported by density functional theory (DFT) calculations. Spectral features of the hyaluronan component were elucidated by simulating the vibrational modes of its two principal disaccharide building blocks. Gels were prepared with varying dipeptide-to-hyaluronan ratios, and their structural characteristics were examined using Raman spectroscopy and atomic force microscopy. The results showed that while NAcAlaNHMA exhibited no significant interaction with the HA matrix, NAcTyrNHMA demonstrated specific binding behavior, as evidenced by notable shifts in its N–H and C–O–H vibrational bands. These findings indicate that NAcTyrNHMA binds to hyaluronic acid via hydrogen bonding, likely involving carboxyl and hydroxyl functional groups. This study highlights the potential for selective tuning of HA-based hydrogels using dipeptides, with implications for biomedical applications such as drug delivery, antimicrobial gels and biomaterial design. Full article

Thyroid eye disease (TED) is characterized by autoimmune inflammation and structural remodelling of orbital tissues, which is a consequence of the activation of orbital fibroblasts (OFs). As a result of this activation, the production of hyaluronan (HA) and the proliferation and adipocyte differentiation of OFs are enhanced. Adipogenesis leads to additional accumulation of HA. The aim of this study was to elucidate the molecular weight distribution of HA produced by OFs under basic conditions and after adipogenic stimuli. The concentration and the molecular weight distribution of HA were examined using ELISA and agarose gel electrophoresis, respectively, in TED (n = 3) and non-TED (n = 3) OF cultures. Under adipogenic stimuli, HA production is increased in OFs. In TED OF cultures, which, unlike non-TED OFs, can differentiate into adipocytes, the enhanced proportion of high-molecular-weight (HMW) HA of more than 2000 kDa is responsible for the increased HA concentration in the culture media. In non-TED OF cultures, which contain a negligible number of differentiating cells after adipogenic stimulation, the medium-molecular-weight (MMW) HA fragments from 50 to 1000 kDa also contribute to the enhanced HA content. Increased production of HMW-HA during adipocyte differentiation of TED OFs is responsible for the elevated HA content in the culture media, which may be an important contributor to both connective tissue matrix expansion and edema in the pathogenesis of TED. Full article

HA (hyaluronan) has been considered in recent years as a naturally occurring modifiable gel-like scaffold that has the capability to absorb and release drugs over an extended period of time making it suitable as a potential chemotherapeutic delivery agent. Considering the limited treatment options available in the treatment of glioblastoma, in this review, we discuss the novel utilisation of ultra-high molecular weight HA—originally identified as a mechanism for maintaining longevity in the naked mole-rat—as both a protective and extracellular matrix-optimizing colloidal scaffold, and a means to deliver therapy in resected brain tumours. The unique properties of this unique form of HA cross-linked gel indicate potential future use in the prevention and treatment of both proliferative-based and inflammation-driven disease. Full article

Hyaluronan (HA) is one of the crucial components of the extracellular matrix in vertebrates and is synthesized by three hyaluronan synthases (HASs), namely HAS1, HAS2, and HAS3. The low expression level of HASs in normal keratinocytes and other various types of cells presents a recognized challenge, impeding biological and pathological research on their localization. In this study, the human proteins HAS1, HAS2, and HAS3 with fused maltose-binding protein (MBP) tags were successfully expressed at high levels and purified for the first time in HEK293F cells. The enzymatic properties of the three HAS proteins were further characterized and compared. A pulse-field gel electrophoresis analysis of the size distribution of the hyaluronan generated in vitro by the membrane proteins demonstrated that the three HAS isoforms generate HA polymer chains at different molecular masses. Kinetic studies demonstrated that the three HAS proteins differed in their catalytic efficiency and apparent K_m values for the two substrates, UDP-GlcA and UDP-GlcNAc. Furthermore, the cellular hyaluronan secretion by the three isoenzymes was evaluated and quantified in the HEK 293T cells transfected with GFP-tagged HAS1-GFP, HAS2-GFP, and HAS3-GFP using an ELISA assay. These findings enhance our understanding of the membrane protein HASs in mammalian cells. Full article

The well-known “click chemistry” reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) was used to transform under very mild conditions hyaluronan-based graft copolymers HA(270)-FA-Pg into the crosslinked derivatives HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL. In particular, medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted at various extents (i.e., 10, 20, and 40%) with fluorogenic ferulic acid (FA) residue bonding propargyl groups were used in the CuAAC reaction with novel azido-terminated crosslinking agents Tri(Ethylene Glycol) Ethyl Resorcinol Acrylate (TEGERA) and Hexa(Ethylene Glycol) Ethyl Resorcinol Acrylate (HEGERA). The resulting HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL materials were characterized from the point of view of their structure by performing NMR studies. Moreover, the swelling behavior and rheological features were assessed employing TGA and DSC analysis to evaluate the potential gel-like properties of the resulting crosslinked materials. Despite the 3D crosslinked structure, HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL frameworks showed adequate swelling performance, the required shear thinning behavior, and coefficient of friction values close to those of the main commercial HA solutions used as viscosupplements (i.e., 0.20 at 10 mm/s). Furthermore, the presence of a crosslinked structure guaranteed a longer residence time. Indeed, HA(270)-FA-TEGERA-CL-40 and HA(270)-FA-HEGERA-CL-40 after 48 h showed a four times greater enzymatic resistance than the commercial viscosupplements. Based on the promising obtained results, the crosslinked materials are proposed for their potential applicability as novel viscosupplements. Full article

Glucocorticoids are often used and highly effective anti-inflammatory medications, but prolonged topical application may alter the epidermis’ normal structure and function, potentially resulting in a number of adverse effects. Topical glucocorticoid-induced skin inflammation is a dangerous condition that develops after topical glucocorticoid use. The patients become dependent on the medication and, even after the medication is stopped, the dermatitis symptoms recur, severely impairing their quality of life. Thus, the need to aggressively confront Topical glucocorticoid-induced skin inflammation is critical. Prior research has demonstrated that topical administration of licorice’s flavonoid component liquiritin stimulates epidermal proliferation, which in turn enhances the creation of collagen and the healing of wounds. Therefore, the purpose of this work was to determine if topical use of liquiritin carbomer gel can treat glucocorticoid-induced changes in mice skin epidermal function, and the mechanisms involved. The findings demonstrated that, in the mice model of topical glucocorticoid-induced skin inflammation, liquiritin carbomer gel aided in the restoration of skin barrier function. These outcomes may have been caused by enhanced expression of the proteins Aquaporin 3, Keratin 10, and Claudin-1, as well as the restoration of epidermal hyaluronan content. In the meantime, liquiritin carbomer gel dramatically decreased the expression of TNF-α, IL-1β, IL-6, IFN-γ, and IgE in mice, according to ELISA tests. Furthermore, topical treatment of liquiritin carbomer gel boosted the expression of superoxide dismutase, catalase, and decreased malondialdehyde expression, potentially counteracting the detrimental effects of glucocorticoids on the epidermis. In summary, these findings imply that topical liquiritin carbomer gel can treat glucocorticoid-induced skin damage through various mechanisms of action. Full article

Hyaluronic acid, in the form of a gel or viscoelastic colloidal solution, is currently used for the viscosupplementation of joints affected by osteoarthritis, but its effectiveness is under debate in relation to newer alternatives. Based on meta-analytical arguments, the present article reinforces the opinion that there are still no decisive arguments for its complete replacement but for its use adapted to the peculiarities of the disease manifestation and of the patients. A “broad” comparison is first made with almost all alternatives studied in the last decade, and then a meta-regression study is performed to compare and predict the effect size induced by viscosupplementation therapy and its main challenger of clinical interest, the platelet-rich plasma treatment. If they are computerized, the developed models can represent tools for clinicians in determining the appropriateness of the option or not for viscosupplementation in a manner adapted to the pain felt by the patients, to their age, or to other clinical circumstances. The models were generated using algorithms implemented in the R language and assembled in different R packages. All primary data and necessary R scripts are provided in accordance with the philosophy of reproducible research. Finally, we adhere in a documented way to the opinion that HA-based products, currently under circumspection, are still clinically useful. Full article

Liver diseases represent a considerable burden to patients and healthcare systems. Hydrogels play an important role in the engineering of soft tissues and may be useful for embedding hepatocytes for different therapeutic interventions or the development of in vitro models to study the pathogenesis of liver diseases or testing of drugs. Here, we developed two types of hydrogels by crosslinking hydrazide-functionalized gelatin with either oxidized dialdehyde hyaluronan or alginate through the formation of hydrazone bonds. Gel formulations were studied through texture analysis and rheometry, showing mechanical properties comparable to those of liver tissue while also demonstrating long-term stability. The biocompatibility of hydrogels and their ability to host hepatocytes was studied in vitro in comparison to pure gelatin hydrogels crosslinked by transglutaminase using the hepatocellular line HepG2. It was found that HepG2 cells could be successfully embedded in the hydrogels, showing no signs of gel toxicity and proliferating in a 3D environment comparable to pure transglutaminase cross-linked gelatin hydrogels used as control. Altogether, hydrazide gelatin in combination with oxidized polysaccharides makes stable in situ gelling systems for the incorporation of hepatocytes, which may pave the way for use in liver tissue engineering and drug testing. Full article

Hyaluronan (HA) is a natural biodegradable biopolymer; its biological functions include cell adhesion, cell proliferation, and differentiation as well as decreasing inflammation, angiogenesis, and regeneration of damaged tissue. This makes it a suitable candidate for fabricating nanomaterials with potential use in tissue engineering. However, HA nanofiber production is restricted due to the high viscosity, low evaporation rate, and high surface tension of HA solutions. Here, hybrids in the form of continuous and randomly aligned polyvinyl alcohol (PVA)–(HA)–siloxane nanofibers were obtained using an electrospinning process. PVA–HA fibers were crosslinked by a 3D siloxane organic–inorganic matrix via sol-gel that restricts natural hydrophilicity and stiffens the structure. The hybrid nanofiber mats were characterized by FT-IR, micro-Raman spectroscopy, SEM, and biological properties. The PVA/HA ratio influenced the morphology of the hybrid nanofibers. Nanofibers with high PVA content (10PVA-8 and 10PVA-10) form mats with few beaded nanofibers, while those with high HA content (5PVA-8 and 5PVA-10) exhibit mats with mound patterns formed by “ribbon-like” nanofibers. The hybrid nanofibers were used as mats to support osteoblast growth, and they showed outstanding biological properties supporting cell adhesion, cell proliferation, and cell differentiation. Importantly, the 5PVA-8 mats show 3D spherical osteoblast morphology; this suggests the formation of tissue growth. These novel HA-based nanomaterials represent a relevant advance in designing nanofibers with unique properties for potential tissue regeneration. Full article

At present, only a few reports have addressed the possible contribution of the lymphatic vascular system to the pathogenesis of systemic sclerosis (SSc). Based on the evidence that blood vascular endothelial cells can undertake the endothelial-to-myofibroblast transition (EndMT) contributing to SSc-related skin fibrosis, we herein investigated whether the lymphatic endothelium might represent an additional source of profibrotic myofibroblasts through a lymphatic EndMT (Ly-EndMT) process. Skin sections from patients with SSc and healthy donors were immunostained for the lymphatic endothelial cell-specific marker lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) in combination with α-smooth muscle actin (α-SMA) as the main marker of myofibroblasts. Commercial human adult dermal lymphatic microvascular endothelial cells (HdLy-MVECs) were challenged with recombinant human transforming growth factor-β1 (TGFβ1) or serum from SSc patients and healthy donors. The expression of lymphatic endothelial cell/myofibroblast markers was measured by quantitative real-time PCR, Western blotting and immunofluorescence. Collagen gel contraction assay was performed to assess myofibroblast-like cell contractile ability. Lymphatic endothelial cells in intermediate stages of the Ly-EndMT process (i.e., coexpressing LYVE-1 and α-SMA) were found exclusively in the fibrotic skin of SSc patients. The culturing of HdLy-MVECs with SSc serum or profibrotic TGFβ1 led to the acquisition of a myofibroblast-like morphofunctional phenotype, as well as the downregulation of lymphatic endothelial cell-specific markers and the parallel upregulation of myofibroblast markers. In SSc, the Ly-EndMT might represent a previously overlooked pathogenetic process bridging peripheral microlymphatic dysfunction and skin fibrosis development. Full article

Periprosthetic joint infections (PJIs) in arthroplasty and osteosynthesis-associated infections (OAIs) in reconstructive surgery still represent a challenging complication in orthopaedics and traumatology causing a burden worsening the patient’s quality of life, for caregiver and treating physicians, and for healthcare systems. PJIs and OAIs are the result of bacterial adhesion over an implant surface with subsequent biofilm formation. Therefore, the clinical pathological outcome is a difficult-to-eradicate persistent infection. Strategies to treat PJIs and OAIs involve debridement, the replacement of internal fixators or articular prostheses, and intravenous antibiotics. However, long treatments and surgical revision cause discomfort for patients; hence, the prevention of PJIs and OAIs represents a higher priority than treatment. Local antibiotic treatments through coating-release systems are becoming a smart approach to prevent this complication. Hydrophilic coatings, loaded with antibiotics, simultaneously provide a barrier effect against bacterial adhesion and allow for the local delivery of an antibiotic. The intraoperative use of a hyaluronan (HY)-derivative coating in the form of a gel, loaded with antibiotics to prevent PJI, has recently raised interest in orthopaedics. Current evidence supports the use of this coating in the prophylaxis of PJI and IRIs in terms of clinical outcomes and infection reduction. Thus, the purpose of this narrative review is to assess the use of a commercially available HY derivative in the form of a gel, highlighting the characteristics of this biomaterial, which makes it attractive for the management of PJIs and IRIs in orthopaedics and traumatology. Full article

Biopolymer hydrogels have become an important group of biomaterials in experimental and clinical use. However, unlike metallic or mineral materials, they are quite sensitive to sterilization. The aim of this study was to compare the effects of gamma irradiation and supercritical carbon dioxide (scCO₂) treatment on the physicochemical properties of different hyaluronan (HA)- and/or gelatin (GEL)-based hydrogels and the cellular response of human bone marrow-derived mesenchymal stem cells (hBMSC). Hydrogels were photo-polymerized from methacrylated HA, methacrylated GEL, or a mixture of GEL/HA. The composition and sterilization methods altered the dissolution behavior of the biopolymeric hydrogels. There were no significant differences in methacrylated GEL release but increased methacrylated HA degradation of gamma-irradiated samples. Pore size/form remained unchanged, while gamma irradiation decreased the elastic modulus from about 29 kPa to 19 kPa compared to aseptic samples. HBMSC proliferated and increased alkaline phosphatase activity (ALP) particularly in aseptic and gamma-irradiated methacrylated GEL/HA hydrogels alike, while scCO₂ treatment had a negative effect on both proliferation and osteogenic differentiation. Thus, gamma-irradiated methacrylated GEL/HA hydrogels are a promising base for multi-component bone substitute materials. Full article

Cell cultures of dispersed cells within hydrogels depict the interaction of the cell–extracellular matrix (ECM) in 3D, while the coculture of different cells within spheroids combines both the effects of cell–cell and cell–ECM interactions. In this study, the cell co-spheroids of human bone mesenchymal stem cells/human umbilical vein endothelial cells (HBMSC/HUVECs) are prepared with the assistance of a nanopattern, named colloidal self-assembled patterns (cSAPs), which is superior to low-adhesion surfaces. A phenol-modified gelatin/hyaluronan (Gel-Ph/HA-Ph) hydrogel is used to encapsulate the multicellular spheroids and the constructs are photo-crosslinked using blue light. The results show that Gel-Ph/HA-Ph hydrogels with a 5%-to-0.3% ratio have the best properties. Cells in HBMSC/HUVEC co-spheroids are more favorable for osteogenic differentiation (Runx2, ALP, Col1a1 and OPN) and vascular network formation (CD31+ cells) compared to HBMSC spheroids. In a subcutaneous nude mouse model, the HBMSC/HUVEC co-spheroids showed better performance than HBMSC spheroids in angiogenesis and the development of blood vessels. Overall, this study paves a new way for using nanopatterns, cell coculturing and hydrogel technology for the generation and application of multicellular spheroids. Full article

The cross-linking of polysaccharides is a universal approach to affect their structure and physical properties. Both physical and chemical methods are used for this purpose. Although chemical cross-linking provides good thermal and mechanical stability for the final products, the compounds used as stabilizers can affect the integrity of the cross-linked substances or have toxic properties that limit the applicability of the final products. These risks might be mitigated by using physically cross-linked gels. In the present study, we attempted to obtain hybrid materials based on carbon nonwovens with a layer of cross-linked hyaluronan and peptides that are fragments of bone morphogenetic proteins (BMPs). A variety of cross-linking procedures and cross-linking agents (1,4-butanediamine, citric acid, and BDDE) were tested to find the most optimal method to coat the hydrophobic carbon nonwovens with a hydrophilic hyaluronic acid (HA) layer. Both the use of hyaluronic acid chemically modified with BMP fragments and a physical modification approach (layer-by-layer method) were proposed. The obtained hybrid materials were tested with the spectrometric (MALDI-TOF MS) and spectroscopic methods (IR and 1H-NMR). It was found that the chemical cross-linking of polysaccharides is an effective method for the deposition of a polar active substance on the surface of a hydrophobic carbon nonwoven fabric and that the final material is highly biocompatible. Full article

Current limitations of wound dressings for treating chronic wounds require the development of novel approaches. One of these is the immune-centered approach, which aims to restore the pro-regenerative and anti-inflammatory properties of macrophages. Under inflammatory conditions, ketoprofen nanoparticles (KT NPs) can reduce pro-inflammatory markers of macrophages and increase anti-inflammatory cytokines. To assess their suitability as part of wound dressings, these NPs were combined with hyaluronan (HA)/collagen-based hydro- (HGs) and cryogels (CGs). Different HA and NP concentrations and loading techniques for NP incorporation were used. The NP release, gel morphology, and mechanical properties were studied. Generally, colonialization of the gels with macrophages resulted in high cell viability and proliferation. Furthermore, direct contact of the NPs to the cells reduced the level of nitric oxide (NO). The formation of multinucleated cells on the gels was low and further decreased by the NPs. For the HGs that produced the highest reduction in NO, extended ELISA studies showed reduced levels of the pro-inflammatory markers PGE2, IL-12 p40, TNF-α, and IL-6. Thus, HA/collagen-based gels containing KT NPs may represent a novel therapeutic approach for treating chronic wounds. Whether effects observed in vitro translate into a favorable profile on skin regeneration in vivo will require rigorous testing. Full article