Small, non-enveloped RNA viruses belonging to the genera Sapovirus, Kobuvirus, and Mamastrovirus are usually associated with gastroenteritis in humans and animals. These enteric pathogens are considered potential zoonotic agents. In this study, the prevalence and genetic diversity of sapoviruses (SaVs), kobuviruses (KoVs), and astroviruses (AstVs) in asymptomatic pigs were investigated using a PCR approach. KoV was found to be the most prevalent virus (87.3 %), followed by AstV (34.2 %) and SaV (10.2 %). Interestingly, the intra- and inter-cluster distances between porcine SaV capsid sequences revealed one strain (P38/11/CZ) that formed a new genotype within genogroup III of porcine SaVs, and it is tentatively called "P38/11-like" genotype. Moreover, this is the first report of porcine kobuvirus detection on Czech pig farms. The high prevalence rate of gastroenteritis-producing viruses in clinically healthy pigs represents a continuous source of infection of pigs, and possibly to humans.

Injectable hydrogels that aim to mechanically stabilise the weakened left ventricle (LV) wall to restore cardiac function or to deliver stem cells in cardiac regenerative therapy have shown promising data. However, the clinical translation of hydrogel-based therapies has been limited due to difficulties injecting them through catheters. We have engineered a novel catheter (AMCath) that overcomes translational hurdles associated with delivering fast-gelling covalently cross-linked hyaluronic acid hydrogels to the myocardium. We developed an experimental technique to measure the force required to inject such hydrogels and determined the mechanical/ viscoelastic properties of the resulting hydrogels. The preliminary in vivo feasibility of delivering fast-gelling hydrogels through AMCath was demonstrated by accessing the porcine LV and showing that the hydrogel was retained in the myocardium postinjection (three 200μL injections delivered, 192, 204 and 183μL measured). However, the mechanical properties of the hydrogels were reduced by passage through AMCath (≤20.62% reduction). We have also shown AMCath can be used to deliver c-ADSC loaded hydrogels without compromising the viability (80% viability) of the c-ADSCs in vitro. Therefore, we show that hydrogel/catheter compatibility issues can be overcome as we have demonstrated the minimally invasive delivery of a fast gelling covalently cross-linked hydrogel to the beating myocardium.

Hydrogel scaffolds which bridge the lesion, together with stem cell therapy represent a promising approach for spinal cord injury (SCI) repair. In this study, a hydroxyphenyl derivative of hyaluronic acid (HA-PH) was modified with the integrin-binding peptide arginine-glycine-aspartic acid (RGD), and enzymatically crosslinked to obtain a soft injectable hydrogel. Moreover, addition of fibrinogen was used to enhance proliferation of human Wharton's jelly-derived mesenchymal stem cells (hWJ-MSCs) on HA-PH-RGD hydrogel. The neuroregenerative potential of HA-PH-RGD hydrogel was evaluated in vivo in acute and subacute models of SCI. Both HA-PH-RGD hydrogel injection and implantation into the acute spinal cord hemisection cavity resulted in the same axonal and blood vessel density in the lesion area after 2 and 8 weeks. HA-PH-RGD hydrogel alone or combined with fibrinogen (HA-PH-RGD/F) and seeded with hWJ-MSCs was then injected into subacute SCI and evaluated after 8 weeks using behavioural, histological and gene expression analysis. A subacute injection of both HA-PH-RGD and HA-PH-RGD/F hydrogels similarly promoted axonal ingrowth into the lesion and this effect was further enhanced when the HA-PH-RGD/F was combined with hWJ-MSCs. On the other hand, no effect was found on locomotor recovery or the blood vessel ingrowth and density of glial scar around the lesion. In conclusion, we have developed and characterized injectable HA-PH-RGD based hydrogel, which represents a suitable material for further combinatorial therapies in neural tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1129-1140, 2018.

A co-crosslinked gelatin and hyaluronan based matrix is a suitable microenvironment for the 3D culture of THP-1 cells, which enhances their differentiation into macrophages.

Hydrogels made from the derivatives of gelatin and hyaluronic acid were used as coatings to control the immune responses.

No abstract

Osteoarthritis (OA) is one of the most common musculoskeletal disorders in the world. OA is often associated with the loss of viscoelastic and tribological properties of synovial fluid (SF) due to degradation of hyaluronic acid (HA) by reactive oxygen species (ROS) and hyaluronidases. Viscosupplementation is one of the ways how to effectively restore SF functions. However, current viscosupplementation products provide only temporal therapeutic effect because of short biological half‐life. In this article we describe a novel device for viscosupplementation (NV) based on the cross‐linked tyramine derivative of HA, chondroitin sulfate (CS), and high molecular weight HA by online determination of viscoelastic properties loss during degradation by ROS and hyaluronidase. Rheological and tribological properties of developed viscosupplement were compared with HA solutions with different molecular weights in the range 500–2000 kDa, which are currently commonly used as medical devices for viscosupplementation treatment. Moreover, based on clinical practice and scientific literature all samples were also diluted by model OA SF in the ratio 1:1 (vol/vol) to better predict final properties after injection to the joint. The observed results confirmed that NV exhibits appropriate rheological properties (viscosity, elastic, and viscous moduli) comparable with healthy SF and maintain them during degradation for a significantly longer time than HA solutions with molecular weight in the range 500–2000 kDa and cross‐linked material without CS.

Osteoarthritisis a highly prevalent musculoskeletal disorder characterized by degradation of cartilage and synovial fluid (SF). Platelet derivatives as platelet‐rich plasma (PRP) and platelet lysate have great potential in the treatment of osteoarthritis because they contain biologically active substances including growth factors (GFs). Rapid release of GFs and their short biological half‐life are factors that can limit the therapeutic impact of PRP therapy. Herein, the first work that describes hydrogels based on polyaldehyde derivative of hyaluronic acid (HA‐OX) as carriers of platelet derivatives for in situ applications is presented, which can be a possible solution to the problem. HA‐OX hydrogels containing 50% (w/w) of PRP or platelet lysate can be injected using a syringe due to low viscosity(<10 Pa s) and injection force (<20 N), and reach elastic modulus up to 2000 Pa. Insulin‐like GF‐1 and Platelet‐derived GF‐AB release from HA‐OX hydrogels (mesh size 297–406 nm) by Fickian and non‐Fickian diffusion respectively. The released PRP GFs maintain their ability to induce cell proliferation (87%–92%). Based on the obtained results, the unique concept of a new material that can restore viscoelastic properties of SF and at the same time gradually deliver GFs from platelet derivatives is designed.