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As a kind of natural protein derived material, gelatin has been widely used in the preparation of medical hydrogels due to its good biocompatibility, non-immunogenicity and the ability of promoting cell adhesion. Functionalization of gelatin-based hydrogels is a hot topic in research and its clinic application. Herein, a novel gelatin-based adhesive hydrogel was prepared via mussel-inspired chemistry. Gelatin was firstly functionalized by dopamine to form dopamine grafted gelatin (GelDA). After the mixture with 1,4-phenylenebisboronic acid and graphene oxide (GO), the GelDA/GO hydrogels were obtained by H 2 O 2 /HRP (horseradish peroxidase) catalytic system. Based on the self-healing and tissue adhesion of the hydrogels, the hemostatic property has been exhibited in the rat hepatic hemorrhage model. Additionally, the incorporation of GO endowed conductivity and enhanced the mechanical property of GelDA/GO hydrogels. The electromyography (EMG) signals of finger movement were successfully monitored by using hydrogel as the adhesive electrodes of EMG monitor. L929 cell experiments showed that the hydrogels had good cytocompatibility. The results indicated the potential application of GelDA/GO hydrogels in tissue adhesives, wound dressings, and wearable devices., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Essentials Hemophilia patients on concizumab prophylaxis may need rFVIIa to treat breakthrough bleeds. Effect and safety of concizumab + rFVIIa were tested in vitro and in vivo. Concizumab + rFVIIa had no additive effects on bleeding in hemophilic rabbits. High steady-state levels of concizumab did not affect the safety of rFVIIa in cynomolgus monkeys. SUMMARY: Background Concizumab is a monoclonal antibody (mAb) against tissue factor pathway inhibitor (TFPI), currently in clinical development as a subcutaneous prophylactic therapy for hemophilia A/B with and without inhibitors. In patients with inhibitors, the treatment choice for breakthrough bleeding will comprise bypassing agents, e.g. activated recombinant FVIIa (rFVIIa) or activated prothrombin complex concentrates. Objectives To explore the effect and safety of concizumab and rFVIIa when they are simultaneously present. Methods Human blood made hemophilic with a FVIII antibody was spiked with increasing concentrations of concizumab, rFVIIa, or concizumab and rFVIIa in combination, and this was followed by thrombin generation test or thromboelastography. Blood loss in hemophilic rabbits was measured when concizumab, rFVIIa or concizumab + rFVIIa was administered either before or during cuticle bleeding. In a safety study, cynomolgus monkeys were exposed to high steady-state concizumab concentrations and given three doses of rFVIIa, and then subjected to full necropsy and histopathological examination. Results In human blood, concizumab + rFVIIa had more pronounced procoagulant effects under hemophilic conditions than the sum of individual responses. In contrast, concizumab + rFVIIa had no additional effects on blood loss in hemophilic rabbits as compared with rFVIIa or concizumab alone. In cynomolgus monkeys, the macroscopic and microscopic pathological examinations revealed no thrombi or other signs of excessive coagulation activation. Both rFVIIa and concizumab caused increases in thrombin-antithrombin and D-dimer concentrations; this effect tended to be additive with concomitant administration. Conclusions Concizumab did not affect the potency or safety of rFVIIa in vivo. These results support a clinical evaluation of rFVIIa at standard dose (90 μg kg -1 ) to treat breakthrough bleeds in concizumab clinical trials., (© 2019 International Society on Thrombosis and Haemostasis.)

Background and Study Aims: Tissue adhesives are commonly used. The aim of this study was to assess the efficacy and hepatotoxicity of intravenous injection of N-butyl cyanoacrylate versus alpha-cyanoacrylate in a rabbit model., Materials and Methods: A total of 20 rabbits were divided into three groups: group I included four rabbits injected with lipiodol in the dorsal vein of a pinna (control group); group II included eight rabbits injected with N-butyl cyanoacrylate/lipiodol; and group III included eight rabbits injected with alpha-cyanoacrylate/lipiodol. All animals were left under normal living conditions for 1week, and then euthanised. Specimens of ear and liver were taken and fixed in 10% formalin saline for histological examination. Secondary fixation was performed using Bouin solution. Specimens of ear were decalcified in ethylenediaminetetraacetic acid (EDTA) at room temperature for 3months. Then, all specimens were processed, embedded in paraffin, sectioned, and stained with haematoxylin and eosin stains for microscopic examination., Results: Microscopic examination of all specimens of the control group revealed normal structure of pinna and liver tissue. Both test groups demonstrated a wide variability of structural changes ranging from oedema and congestion to necrosis and marked cellular inflammatory infiltration. The two groups were compared using a self-designed inflammatory score. This revealed that alpha-cyanoacrylate caused more venous sclerosis with extensive perivenous reaction and hepatotoxicity than both N-butyl cyanoacrylate and control (p<0.05 and p<0.05). N-butyl cyanoacrylate was also found to cause more venous sclerosis and hepatotoxicity than control (p<0.05)., Conclusion: This study suggested that injection of Krazy Glue, either the clinically usable N-butyl cyanoacrylate or the commercially available alpha-cyanoacrylate, caused comparable venous sclerosis. Unfortunately, both induced significant hepatotoxicity. Therefore, neither of them should be used unless all other safe options are absent. Larger studies have to be conducted and effects of these components on other organs should be investigated; however, caution must be exercised in their clinical use., (Copyright © 2016 Arab Journal of Gastroenterology. Published by Elsevier B.V. All rights reserved.)

Background: Achieving hemostasis during surgery is a common challenge across surgical specialties and procedures, including cardiovascular and peripheral vascular procedures. Although several hemostatic agents are available, they all become less effective as bleeding becomes more vigorous. Veriset™ hemostatic patch is a topical hemostatic agent that has been approved for use on solid organs and in soft tissue. The primary aim of these studies was to assess the safety of Veriset hemostatic patch during cardiovascular and peripheral vascular procedures., Methods: Adult domestic swine were given intraoperative anticoagulation and systemic antiplatelet therapy, and then underwent a variety of cardiovascular coronary artery bypass graft (CABG anastomosis and aortotomy closure) and peripheral vascular (carotid arteriotomy with patch angioplasty) procedures. Bleeding was identified or created from each anastomotic site and was brisk in many cases. Veriset hemostatic patch, Surgicel(®) Nu-Knit(®) absorbable hemostat, or standard of care treatment was applied topically to the site of bleeding, and time to hemostasis was monitored for each animal. Animals were assessed during and after the surgical procedure to determine the effects of treatment on vessel diameter, clinical laboratory parameters, and host tissue response and/or tissue integration., Results: Application of Veriset hemostatic patch had no effect on vessel diameter, similar to Surgicel Nu-Knit absorbable hemostat and standard of care treatment. Approximately 28 days after application, Veriset hemostatic patch and Surgicel Nu-Knit absorbable hemostat were completely absorbed, with no impact on serum chemistry profiles. Furthermore, Veriset hemostatic patch was as effective or more effective than Surgicel Nu-Knit absorbable hemostat when applied during carotid arteriotomy (30.0 ± 0.0 sec vs. 163.6 ± 86.9 sec, P < 0.001) and CABG anastomosis (91.9 ± 66.0 sec vs. 207.5 ± 159.2 sec, P = 0.053)., Conclusions: Veriset hemostatic patch exhibits similar safety as Surgicel Nu-Knit absorbable hemostat, with effectiveness against cardiovascular and peripheral vascular bleeding. If these preclinical results are confirmed in clinical trials, this highly effective patch with a topical application requiring less than 30 seconds is likely to prove useful in many clinical settings., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Natural polymer-derived materials have attracted increasing interest in the biomedical field. Polysaccharides have obvious advantages over other polymers employed for biomedical applications due to their exceptional biocompatibility and biodegradability. None of the spherical embolic agents used clinically is biodegradable. In the current study, microspheres prepared from chitosan and carboxymethyl cellulose (CMC) were investigated as a biodegradable embolic agent for arterial embolization applications. Aside from the enzymatic degradability of chitosan units, the cross-linking bonds in the matrix, Schiff bases, are susceptible to hydrolytic cleavage in aqueous conditions, which would overcome the possible shortage of enzymes inside the arteries. The size distribution, morphology, water retention capacity and degradability of the microspheres were found to be affected by the modification degree of CMC. An anticancer drug, doxorubicin, was successfully incorporated into these microspheres for local release and thus for killing cancerous cells. These microspheres demonstrated controllable degradation time, variable swelling and tunable drug release profiles. Co-culture with human umbilical vein endothelial cells revealed non-cytotoxic nature of these microspheres compared to monolayer control (P>0.95). In addition, a preliminary study on the in vivo degradation of the microspheres (100-300μm) was performed in a rabbit renal embolization model, which demonstrated that the microspheres were compatible with microcatheters for delivery, capable of occluding the arteries, and biodegradable inside arteries. These microspheres with biodegradability would be promising for embolization therapies., (Copyright © 2013. Published by Elsevier Ltd.)

High molecular weight chitosan (HMWCS) is effective at hemostasis and wound healing, and will be potentially used on injured internal organs. To study its prenatal and developmental effect in vivo, forty-four ICR pregnant mice per group were singly injected intraperitoneally at 0, 125, 500 or 2000 mg/kg body weight, respectively, on gestation day 6 (GD6). Clinical signs, reproductive capacity, fetus and infant developments, and histopathological changes were then observed. The results showed that the treatment of HMWCS could decrease body weights and food consumptions, and induce diarrhea, vaginal bleeding, and some other adverse effects in F0 mice. For the emaciation and threatened abortion of pregnant mice, the numbers of live fetuses and early resorption were reduced significantly in HMWCS groups. However, the developments of F1 and F2 mice were not affected, except for lower weights of the body and some organs. In addition, the NOAEL of HMWCS in maternal toxicity was considered to be less than 125 mg/kg, and the NOAEL in developmental toxicity was 125 mg/kg., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Recombinant human thrombin (rhThrombin) is being developed as an alternative to thrombin products purified from pooled human or bovine plasma, which are currently marketed for topical hemostasis. Preclinical studies of rhThrombin were conducted prior to its evaluation as a topical adjunct to surgical hemostasis in clinical trials. No overt clinical pathology or signs were observed in cynomolgus monkeys following implantation of a gelatin sponge containing either rhThrombin or bovine thrombin to a surgical liver wound, and similar gross and microscopic wound healing characteristics were observed over an eight-week recovery period with either compound. Repeated subcutaneous injections of rhThrombin or bovine thrombin to cynomolgus monkeys produced no treatment-related effects. Whereas no monkeys demonstrated anti-rhThrombin antibody seroconversion, specific anti-bovine antibodies were detected in all tested monkeys exposed to bovine thrombin. Addition of rhThrombin or bovine thrombin to mouse fibroblast cells resulted in expected detachment and shape change. Topical application of rhThrombin to rabbits did not cause irritation to the eye, normal skin, or abraded skin. These studies showed that topical, subcutaneous, or implanted rhThrombin was minimally immunogenic, safe, and well tolerated in nonclinical models, and supported the clinical evaluation of rhThrombin in a variety of surgical settings.

Thrombin has been found in neuritic plaques in Alzheimer's disease (AD). Also, traumatic brain injury, where neurons are exposed to high thrombin levels, is associated with an increased incidence of AD. Our objective was to determine the effects of thrombin administered in vivo on cognitive function and neuropathology. Rats were trained using a radial eight-arm maze and then thrombin (25 or 100 nM, 0.25 microl/h, 28 days) or vehicle was delivered via intracerebroventricular infusion. Animals that received 100 nM thrombin demonstrated cognitive impairments including deficits in reference memory and an increase in task latency. Also, significant neuropathology was detected in these animals such as enlargement of cerebral ventricles, an increased number of TUNEL-positive cells, astrogliosis, and an increase in the immunoreactivity for phosphorylated neurofilament, and apolipoprotein-E fragments. Thrombin-induced changes in cognitive function and ventricular enlargement were inhibited by hirudin. These findings demonstrate that thrombin is a mediator of neurotoxicity and cognitive deficits and suggest that inhibition of thrombin may be a treatment strategy for AD- or head trauma-associated cognitive deficits.

Redox cycling leading to oxidative stress has been proposed as the mechanism by which adriamycin induces glomerular toxicity in rats. The present study compares the extent of the oxidative stress and cytotoxicity induced by adriamycin to menadione (a model redox cycling quinone) in freshly isolated rat glomeruli. Adriamycin and menadione (25 microM) decreased de novo protein synthesis (measured by 3H-proline incorporation into acid-precipitable glomerular protein) by 50 and 85%, respectively, in 2 h. By contrast, menadione at 25 microM reduce glomerular membrane integrity (as assessed by lactate dehydrogenase leakage), adriamycin reduced membrane integrity at 500 microM adriamycin. Reactive oxygen species (ROS) were measured by the oxidation of dihydrodichlorofluorescein. Menadione (25 microM) and adriamycin (25 microM) increased ROS formation to 260 and 156% of controls after 30 min incubation, respectively. Oxidative stress was assessed by measuring the intracellular level of reduced glutathione (GSH) and the decrease of the NADPH/NADP- ratio which stimulates the pentose phosphate pathway (PPP): (a) menadione (25-100 microM) reduced glomerular GSH to 10-20% of controls, adriamycin (25-100 microM) had no effect; (b) menadione (10 microM) increased PPP activity 6-fold, while adriamycin (125 microM) had only a 2-fold effect. Although adriamycin and menadione generate extensive ROS and decrease protein synthesis, there was no correlation between the extent of oxidative stress and cytotoxicity in glomeruli exposed to adriamycin. These results suggest that oxidative stress may not be the primary mechanisms by which adriamycin induces selective glomerular toxicity.

The enzyme DT-diaphorase catalyses the 2-electron reduction of quinones. This reaction may facilitate the detoxification of such compounds, since the hydroquinone so formed can be converted into non-toxic conjugates. There is evidence for the involvement of DT-diaphorase in the detoxification of menadione (2-methyl-1,4-naphthoquinone) in a wide range of cells and tissues in vitro, but no information is available on the possible influence of this enzyme on the harmful effects of menadione in vivo. In animals, menadione is selectively toxic to erythrocytes, causing haemolytic anaemia. In the present study, rats were treated with dicoumarol, an inhibitor of DT-diaphorase, or butylated hydroxyanisole (BHA), a substance that increases the activity of this enzyme in vivo. They were then challenged with a toxic dose of menadione. Dicoumarol increased the severity of menadione-induced haemolytic anaemia while BHA decreased it, consistent with a role for DT-diaphorase in the detoxification of menadione in vivo, as previously described in vitro.

Incubation of cultured Chinese hamster V79 cells with menadione (2-methyl-1,4-naphthoquinone), a generator of superoxide anion radicals, caused a rapid increase in the level of glutathione disulfide (GSSG) and a decrease in the level of glutathione (GSH), which followed a 1.5- to 2-fold increase in the level of GSH during post-treatment incubation. Menadione also caused a concentration- and time-dependent increase in the activity of gamma-glutamylcysteine synthetase (gamma-GCS), a rate-limiting enzyme in the synthesis of GSH. These results suggested that the increase in level of GSH after treatment with menadione was due to the increase in the activity of gamma-GCS. Dicoumarol, an inhibitor of DT-diaphorase, did not influence the increase in the activity of gamma-GCS caused by menadione but it did enhance the cytotoxicity and the increase in the level GSSG caused by menadione. This result suggested that neither the DT-diaphorase-mediated metabolism of menadione nor the increase in level of GSSG caused by menadione was associated with the increase in the activity of gamma-GCS. Chelators of divalent iron and copper (I), and cycloheximide did not influence the increase in the activity of gamma-GCS caused by menadione. Thus, it appeared that reactive oxygen radicals, generated from hydrogen peroxide by an iron- or copper-catalyzed Fenton reaction, were not responsible for the increase in the activity of gamma-GCS and that the increase was not an inducible phenomenon.