Inactivation of the bovine-spongiform-encephalopathy (BSE) agent by the acid and alkaline processes used in the manufacture of bone gelatine

Backflow reduction in local injection therapy with gelatin formulations

The local injection of therapeutic drugs, including cells, oncolytic viruses and nucleic acids, into different organs is an administrative route used to achieve high drug exposure at the site of action. However, after local injection, material backflow and side effect reactions can occur. Hence, this study was carried out to investigate the effect of gelatin on backflow reduction in local injection. Gelatin particles (GPs) and hydrolyzed gelatin (HG) were injected into tissue models, including versatile training tissue (VTT), versatile training tissue tumor-in type (VTT-T), and broiler chicken muscles (BCM), using needle gauges between 23 G and 33 G. The backflow material fluid was collected with filter paper, and the backflow fluid rate was determined. The backflow rate was significantly reduced with 35 μm GPs (p value < .0001) at different concentrations up to 5% and with 75 μm GPs (p value < .01) up to 2% in the tissue models. The reduction in backflow with HG of different molecular weights showed that lower-molecular-weight HG required a higher-concentration dose (5% to 30%) and that higher-molecular-weight HG required a lower-concentration dose (7% to 8%). The backflow rate was significantly reduced with the gelatin-based formulation, in regard to the injection volumes, which varied from 10 μL to 100 μL with VTT or VTT-T and from 10 μL to 200 μL with BCM. The 35 μm GPs were injectable with needles of small gauges, which included 33 G, and the 75 μm GPs and HG were injectable with 27 G needles. The backflow rate was dependent on an optimal viscosity of the gelatin solutions. An optimal concentration of GPs or HG can prevent material backflow in local injection, and further studies with active drugs are necessary to investigate the applicability in tumor and organ injections.

Multifunctional hydrogel dressing based on fish gelatin/oxidized hyaluronate for promoting diabetic wound healing

Non-healing chronic diabetic wound treatment remains an unsolved healthcare challenge and still threatens patients' lives. Recently, hydrogel dressings based on natural biomaterials have been widely investigated to accelerate the healing of diabetic wounds. In this study, we introduce a bioactive hydrogel based on fish gelatin (FG) as a candidate for diabetic wound treatments, which is a recently emerged substitute for mammalian derived gelatin. The composite hydrogel simply fabricated with FG and oxidized hyaluronate (OHy) through Schiff base reaction could successfully accelerate wound healing due to their adequate mechanical stability and self-healing ability. In vitro studies showed that the fabricated hydrogels exhibited cytocompatibility and could reduce pro-inflammatory cytokine expression such as NO, IL-1β, TNF-α, and PGE2 in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. In addition, the production of reactive oxygen species (ROS), a key marker of free radicals producing oxidative stress, was also reduced by fabricated hydrogels. Furthermore, in vivo experiments demonstrated that the hydrogel could promote wound closure, re-epithelialization, collagen deposition, and protein expression of CD31, CD206, and Arg1 in diabetic mice models. Our study highlights the advanced potential of FG as a promising alternative material and indicates that FOHI can be successfully used for diabetic wound healing applications.

In Situ Precision Cell Electrospinning as an Efficient Stem Cell Delivery Approach for Cutaneous Wound Healing

Mesenchymal stem cell (MSC) therapies have been brought forward as a promising treatment modality for cutaneous wound healing. However, current approaches for stem cell delivery have many drawbacks, such as lack of targetability and cell loss, leading to poor efficacy of stem cell therapy. To overcome these problems, in the present study, an in situ cell electrospinning system is developed as an attractive approach for stem cell delivery. MSCs have a high cell viability of over 90% even with a high applied voltage of 15 kV post-cell electrospinning process. In addition, cell electrospinning does not show any negative effect on the surface marker expression and differentiation capacity of MSCs. In vivo studies demonstrate that in situ cell electrospinning treatment can promote cutaneous wound healing through direct deposition of bioactive fish gelatin fibers and MSCs onto wound sites, leading to a synergic therapeutic effect. The approach enhances extracellular matrix remodeling by increasing collagen deposition, promotes angiogenesis by increasing the expression of vascular endothelial growth factor (VEGF) and forming small blood vessels, and dramatically reduces the expression of interleukin-6 (IL-6) during wound healing. The use of in situ cell electrospinning system potentially provides a rapid, no touch, personalized treatment for cutaneous wound healing.

Prion Dissemination through the Environment and Medical Practices: Facts and Risks for Human Health

Prion diseases are a group of fatal, infectious neurodegenerative disorders affecting various species of mammals, including humans. The infectious agent in these diseases, termed prion, is composed exclusively of a misfolded protein that can spread and multiply in the absence of genetic materials. In this article, we provide an overview of the mechanisms of prion replication, interindividual transmission, and dissemination in communities. In particular, we review the potential role of the natural environment in prion transmission, including the mechanisms and pathways for prion entry and accumulation in the environment as well as its roles in prion mutation, adaptation, evolution, and transmission. We also discuss the transmission of prion diseases through medical practices, scientific research, and use of biological products. Detailed knowledge of these aspects is crucial to limit the spreading of existing prion diseases as well as to prevent the emergence of new diseases with possible catastrophic consequences for public health.

Potential BSE risk posed by the use of ruminant collagen and gelatine in feed for non-ruminant farmed animals

EFSA was requested to estimate the cattle bovine spongiform encephalopathy (BSE) risk (C-, L- and H-BSE) posed by ruminant collagen and gelatine produced from raw material fit for human consumption, or from material classified as Category 3 animal by-products (ABP), to be used in feed intended for non-ruminant animals, including aquaculture animals. Three risk pathways (RP) were identified by which cattle could be exposed to ruminant feed cross-contaminated with ruminant collagen or gelatine: 1) recycled former foodstuffs produced in accordance with Regulation (EC) No 853/2004 (RP1), 2) technological or nutritional additives or 3) compound feed, produced either in accordance with Regulation (EC) No 853/2004 (RP2a) or Regulation (EU) No 142/2011 (RP2b). A probabilistic model was developed to estimate the BSE infectivity load measured in cattle oral ID 50 (CoID 50)/kg, in the gelatine produced from the bones and hide of one infected animal older than 30 months with clinical BSE (worst-case scenario). The amount of BSE infectivity (50th percentile estimate) in a member state (MS) with negligible risk status was 7.6 × 10-2 CoID 50/kg, and 3.1 × 10-4 CoID 50/kg in a MS with controlled risk status. The assessment considered the potential contamination pathways and the model results (including uncertainties) regarding the current epidemiological situation in the EU and current statutory controls. Given the estimated amount of BSE infectivity to which cattle would be exposed in a single year, and even if all the estimated undetected BSE cases in the EU were used for the production of collagen or gelatine (either using raw materials fit for human consumption or Category 3 ABP raw materials), it was concluded that the probability that no new case of BSE in the cattle population would be generated through any of the three RP is 99-100% (almost certain).

Production of a Recombinant Non-Hydroxylated Gelatin Mimetic in Pichia pastoris for Biomedical Applications

Proteins derived from the natural extracellular matrix like collagen or gelatin are common in clinical research, where they are prized for their biocompatibility and bioactivity. Cells are able to adhere, grow and remodel scaffolds based on these materials. Usually, collagen and gelatin are sourced from animal material, risking pathogenic transmission and inconsistent batch-to-batch product quality. A recombinant production in yeast circumvents these disadvantages by ensuring production with a reproducible quality in animal-component-free media. A gelatin mimetic protein, based on the alpha chain of human collagen I, was cloned in Pichia pastoris under the control of the methanol-inducible alcohol oxidase (AOX1) promoter. A producing clone was selected and cultivated at the 30 L scale. The protein was secreted into the cultivation medium and the final yield was 3.4 g·L-1. Purification of the target was performed directly from the cell-free medium by size exclusion chromatography. The gelatin mimetic protein was tested in cell culture for biocompatibility and for promoting cell adhesion. It supported cell growth and its performance was indistinguishable from animal-derived gelatin. The gelatin-mimetic protein represents a swift strategy to produce recombinant and human-based extracellular matrix proteins for various biomedical applications.

Fabrication of an ultrafine fish gelatin nanofibrous web from an aqueous solution by electrospinning

Electrospinning of aqueous gelatin solution obtained from bovine or porcine sources has been difficult to achieve without additional facilities, such as a temperature control oven or heating cover. Gelatin from cold-water fish has low contents of proline (Pro) and hydroxyproline (Hyp) compared with mammalian-derived gelatin. For this reason, the fish-derived gelatin maintains a sol state without showing gelation behavior at room temperature. In the present study, we prepared an ultrafine fish gelatin nanofibrous web by electrospinning from aqueous solutions without any additive polymers or temperature control facilities. The concentration and viscosity of fish gelatin are the most important factor in determining the electrospinnability and fiber diameter. Electrospinning of aqueous fish gelatin has the highest nanofiber productivity compared to other organic solvent systems. Using glutaraldehyde vapor (GTA), the water stability was improved and substantial enhancement was achieved in the mechanical properties. Finally, the cytotoxicity of a fish gelatin nanofibrous scaffold was evaluated based on a cell proliferation study by culturing human dermal fibroblasts (HDFs) compared with a fish gelatin film and nanofibrous mat from mammalian gelatin. The result shows better initial cell attachment and proliferation compared with the fish gelatin film and no significant difference compared with mammalian-derived gelatin nanofibrous mat. We expect that electrospinning of aqueous fish gelatin could be an effective alternative mammalian gelatin source.

Usefulness of a new gelatin glue sealant system for dural closure in a rat durotomy model

Watertight dural closure is imperative after neurosurgical procedures, because inadequately treated leakage of cerebrospinal fluid (CSF) can have serious consequences. We used a rat durotomy model to test the usefulness of a new gelatin glue as a dural sealant in a rat model of transdural CSF leakage. All rats were randomly divided into one of the following three treatment groups: no application (control group: N = 18), application of fibrin glue (fibrin glue group: N = 18), and application of the new gelatin glue (new gelatin glue group: N = 18). The craniotomy side was re-opened, and CSF leakage was checked and recorded at 1, 7, and 28 days postoperatively. The new gelatin glue was adequate for stopping CSF leakage; no leakage was observed at postoperative days 1 or 7, and leakage was observed in only one rat at postoperative day 28. This result was statistically significant when compared to the control group (P = 0.002, P = 0.015, P = 0.015, respectively). The pathologic score of the new gelatin group was not different from that of the control or fibrin glue groups. We conclude that our new gelatin glue provides effective watertight closure 1, 7, and 28 days after operation in the rat durotomy model.

Effectiveness of a new gelatin sealant system for dural closure

OBJECTIVES

Watertight dural closure is imperative after neurosurgical procedures because inadequately treated leakage of cerebrospinal fluid (CSF) can have serious consequences. In this study, the authors test the use of a new gelatin glue as a dural sealant in in vitro and in vivo canine models of transdural CSF leakage.

METHODS

The in vitro model was sutured semicircles of canine dura mater and artificial dural substitute. The sutures were sealed with gelatin glue (n  =  20), fibrin glue (n  =  20), or a polyethylene glycol (PEG)-based hydrogel sealant (n  =  20). Each sample was set in a device to measure water pressure, and pressure was increased until leakage occurred. Bonding strength was subjectively evaluated. The in vivo model was dogs who underwent dural excision and received either no sealant (control group; n  =  5) or gelatin glue sealant (n  =  5) before dural closure. Twenty-eight days post-surgery, the maximum intracranial pressure was measured at the cisterna magna using Valsalva maneuver and tissue adhesion was evaluated.

RESULTS

The water pressure at which leakage occurred in the in vitro model was higher with gelatin glue (76·5 ± 39·8 mmHg) than with fibrin glue (38·3 ± 27·4 mmHg, P < 0·001) or the PEG-based hydrogel sealant (46·3 ± 20·9 mmHg, P  =  0·007). Bonding strength was higher for the gelatin glue than fibrin glue (P < 0·001) or PEG-based hydrogel sealant (P  =  0·001). The maximum intracranial pressure in the in vivo model was higher for the gelatin glue group (59·0 ± 2·2 mmHg) than the control group (13·8 ± 4·0 mmHg, P < 0·001). Tissue adhesion was lower for the gelatin glue group than the control group (P  =  0·005).

DISCUSSION

The new gelatin glue provides an effective watertight closure when used as an adjunct to sutured dural repair.

High-risk biodegradable waste processing by alkaline hydrolysis

Biodegradable waste is by definition degraded by other living organisms. Every day, meat industry produces large amounts of a specific type of biodegradable waste called slaughterhouse waste. Traditionally in Europe, this waste is recycled in rendering plants which produce meat and bone meal and fat. However, feeding animals with meat and bone meal has been banned since the outbreaks of bovine spongiform encephalopathy (BSE). In consequence, new slaughterhouse waste processing technologies have been developed, and animal wastes have now been used for energy production. Certain parts of this waste, such as brains and spinal cord, are deemed high-risk substances, because they may be infected with prions. Their treatment is therefore possible only in strictly controlled conditions. One of the methods which seems to bear acceptable health risk is alkaline hydrolysis. This paper presents the results of an alkaline hydrolysis efficiency study. It also proposes reuse of the obtained material as organic fertiliser, as is suggested by the analytical comparison between meat and bone meal and hydrolysate.