Activation-dependent adsorption of cytokines and toxins related to liver failure to carbon beads

Therapeutic possibilities of gut microbiota modulation in acute decompensation of liver cirrhosis

The formation of liver cirrhosis (LC) is an unfavorable event in the natural history of chronic liver diseases and with the development of portal hypertension and/or impaired liver function can cause a fatal outcome. Decompensation of LC is considered the most important stratification variable for the risk of death. It is currently postulated that decompensation of LC occurs through an acute (including acute-on-chronic liver failure) and non-acute pathway. Acute decompensation of LC is accompanied by the development of life-threatening complications, characterized by an unfavorable prognosis and high mortality. Progress in understanding the underlying molecular mechanisms has led to the search for new interventions, drugs, and biological substances that can affect key links in the pathogenesis of acute decompensation in LC, for example the impaired gut-liver axis and associated systemic inflammation. Given that particular alterations in the composition and function of gut microbiota play a crucial role here, the study of the therapeutic possibilities of its modulation has emerged as one of the top concerns in modern hepatology. This review summarized the investigations that describe the theoretical foundations and therapeutic potential of gut microbiota modulation in acute decompensation of LC. Despite the encouraging preliminary data, the majority of the suggested strategies have only been tested in animal models or in preliminary clinical trials; additional multicenter randomized controlled trials must demonstrate their efficacy in larger patient populations.

Emerging nanomaterials applied for tackling the COVID-19 cytokine storm

During the global outbreak of coronavirus disease 2019 (COVID-19), a hyperinflammatory state called the cytokine storm was recognized as a major contributor to multiple organ failure and mortality. However, to date, the diagnosis and treatment of the cytokine storm remain major challenges for the clinical prognosis of COVID-19. In this review, we outline various nanomaterial-based strategies for preventing the COVID-19 cytokine storm. We highlight the contribution of nanomaterials to directly inhibit cytokine release. We then discuss how nanomaterials can be used to deliver anti-inflammatory drugs to calm the cytokine storm. Nanomaterials also play crucial roles in diagnostics. Nanomaterial-based biosensors with improved sensitivity and specificity can be used to detect cytokines. In summary, emerging nanomaterials offer platforms and tools for the detection and treatment of the COVID-19 cytokine storm and future pandemic.

The microbiota in cirrhosis and its role in hepatic decompensation

Cirrhosis - the common end-stage of chronic liver disease - is associated with a cascade of events, of which intestinal bacterial overgrowth and dysbiosis are central. Bacterial toxins entering the portal or systemic circulation can directly cause hepatocyte death, while dysbiosis also affects gut barrier function and increases bacterial translocation, leading to infections, systemic inflammation and vasodilation, which contribute to acute decompensation and organ failure. Acute decompensation and its severe forms, pre-acute-on-chronic liver failure (ACLF) and ACLF, are characterised by sudden organ dysfunction (and failure) and high short-term mortality. Patients with pre-ACLF and ACLF present with high-grade systemic inflammation, usually precipitated by proven bacterial infection and/or severe alcoholic hepatitis. However, no precipitant is identified in 30% of these patients, in whom bacterial translocation from the gut microbiota is assumed to be responsible for systemic inflammation and decompensation. Different microbiota profiles may influence the rate of decompensation and thereby outcome in these patients. Thus, targeting the microbiota is a promising strategy for the prevention and treatment of acute decompensation, pre-ACLF and ACLF. Approaches include the use of antibiotics such as rifaximin, faecal microbial transplantation and enterosorbents (e.g. Yaq-001), which bind microbial factors without exerting a direct effect on bacterial growth kinetics. This review focuses on the role of microbiota in decompensation and strategies targeting microbiota to prevent acute decompensation.

Nanotools for Sepsis Diagnosis and Treatment

Sepsis is one of the leading causes of death worldwide with high mortality rates and a pathological complexity hindering early and accurate diagnosis. Today, laboratory culture tests are the epitome of pathogen recognition in sepsis. However, their consistency remains an issue of controversy with false negative results often observed. Clinically used blood markers, C reactive protein (CRP) and procalcitonin (PCT) are indicators of an acute-phase response and thus lack specificity, offering limited diagnostic efficacy. In addition to poor diagnosis, inefficient drug delivery and the increasing prevalence of antibiotic-resistant microorganisms constitute significant barriers in antibiotic stewardship and impede effective therapy. These challenges have prompted the exploration for alternative strategies that pursue accurate diagnosis and effective treatment. Nanomaterials are examined for both diagnostic and therapeutic purposes in sepsis. The nanoparticle (NP)-enabled capture of sepsis causative agents and/or sepsis biomarkers in biofluids can revolutionize sepsis diagnosis. From the therapeutic point of view, currently existing nanoscale drug delivery systems have proven to be excellent allies in targeted therapy, while many other nanotherapeutic applications are envisioned. Herein, the most relevant applications of nanomedicine for the diagnosis, prognosis, and treatment of sepsis is reviewed, providing a critical assessment of their potentiality for clinical translation.

A novel anticoagulant affinity membrane for enhanced hemocompatibility and bilirubin removal

Affinity membrane is widely employed to promote specific adsorption of toxins and reduce the blood purification therapeutic time. However, it suffers from insufficient toxin binding and low hemocompatibility. Herein, a novel anticoagulant affinity membrane (AAM) was developed to clear bilirubin from human blood in a pore-flow-through way. Firstly, a nylon net membrane with a regularly arranged pore as the matrix was coated with poly(pyrrole-3-carboxylic acid) via chemical vapor deposition (CVD) method. Then, poly(L-arginine) (PLA) as a highly specific ligand of bilirubin, was immobilized onto the surface of the composited membrane after the modification of heparin. Owing to the 3-dimensional molecular architecture of PLA, up to 86.1 % of bilirubin was efficiently cleared. Besides, the AAM exhibited effective anticoagulant activity in the measurement of clotting time, with suppressed thrombus formation, low hemolysis ratio, minimized platelet and leukocyte adhesion, and excellent biosafety. Therefore, the AAM has enormous potential in blood purification therapy for enhancing hemocompatibility and bilirubin removal.

Functionalized Carbon Nanotube-Embedded Poly(vinyl alcohol) Microspheres for Efficient Removal of Tumor Necrosis Factor-α

Tumor necrosis factor (TNF)-α has an important role in the pathogenesis of autoimmune and inflammatory diseases such as rheumatoid and septic arthritis. Removal of excess tumor necrosis factor-α (TNF-α) is a promising treatment. In this study, a series of functionalized carbon nanotube-embedded poly(vinyl alcohol) (PVA) nanocomposite adsorbents were prepared for TNF-α removal for the first time. The resulting nanocomposites were characterized by scanning electron microscopy and Raman spectroscopy, which demonstrated that carbon nanotubes were well-dispersed on the surface of PVA macroporous microspheres. Adsorption tests showed that the carboxylated carbon nanotube-embedded composite microspheres (PVA/MWCNTs-COOH) possessed much better adsorption capacity for TNF-α in both simulated serum solution and rat plasma compared to the aminated (PVA/MWCNTs-NH₂) and raw carbon nanotube-embedded microspheres (PVA/MWCNTs-raw). In addition, the effects on hemolytic activity, the anticoagulant property, and the components of blood were negligible, indicating the excellent blood compatibility of composite beads. Our findings suggest that the carboxylated carbon nanotube-embedded composite microspheres may be potentially useful for the treatment of autoimmune and inflammatory diseases by removing TNF-α from the blood.

The effect of two formulations of carbon enterosorbents on oxidative stress indexes and molecular conformation of serum albumin in experimental animals exposed to CCl4

The liver failure means inability to perform its normal synthetic, biotransformation and excretory functions. The disturbance of metabolic processes leads to the development of "metabolic endogenous intoxication" resulting in oxidative stress. Oxidative stress initiates the processes of oxidation of amino acid residues of blood plasma proteins causing the changes in their structure and functions. The effect of administration of highly activated porous carbonic enterosorbents on oxidative stress manifestations and molecular conformation of serum albumin in blood of experimental animals with acute liver failure induced by carbon tetrachloride (CCl4) needs to be investigated. Two forms of activated carbonic enterosorbents such as AC1 (primary beads with the range of diameters of 125-250 μm) and AC2 (secondary granules prepared from micronized AC1 having the mean particle size of ~1 μm) derived from phenol-formaldehyde resin were used in rat model with CCl4 intoxication. The total level of reactive oxygen species (ROS) in blood plasma, the activity of catalase (CAT) in blood hemolysates; the content of reduced glutathione (GSH) in liver homogenates, and the level of oxidative modification of proteins (OMP) such as aldehyde-dinitrophenylhydrazone (A-DNPH) and ketone-dinitrophenylhydrazone (K-DNPH) derivatives in blood plasma and liver homogenates were determined. In addition, the level of pro/antioxidant ratio in blood hemolysates and the content of lipid peroxidation product - malondialdehyde (MDA), in blood plasma and liver were determined. Melting thermograms of blood plasma proteins (BPP) and molecular conformation changes of serum albumin were analyzed by biophysical methods (differential scanning microcalorimetry and spectrofluorimetry). The extent of CCl4-induced oxidative damage in blood and liver of experimental animals was shown to be less expressed for AC1 in comparison with AC2 enterosorbent. However, AC2 used in the form of secondary granules positively influenced some biophysical properties of albumin molecule (temperature of melting, shape of melting endotherm and intrinsic fluorescence) after rats exposure to CCl4. In general, administration of both AC1 and AC2 led to the reduction of oxidative stress manifestations and partial restoration of native molecular conformation of serum albumin. These observations are promising in terms of achieving recovery of detoxification potential of organism after severe liver injury.

Effect of Primary and Secondary Beads of Carbon Enterosorbent on Haematological Parameters and Oxidative Stress Development Caused by Melphalan in Rats

Background and Objectives: Side effects of anti-cancer drugs are usually accompanied by oxidative stress, including myelotoxicity. We evaluated the potential of oral highly activated micro-/macroporous carbon adsorbents (bulk density of 0.16 g/cm3, surface area calculation by Brunauer-Emmett-Teller model (SBET) > 2200 m2/g, derived from proprietary phenolic resin beads) to alleviate oxidative stress and myelotoxicity in rats. Materials and Methods: A single injection of cytostatic melphalan (L-PAM) at a dose of 4 mg/kg was used for modelling. Two forms of activated carbon were used: AC1-primary beads with the particle size range of 125-250 µm, and AC2-micronized AC1 with a mean particle size of ~1 µm. We measured haematological parameters white blood cells, red blood cells, platelet count, and haemoglobin level. Oxidative stress intensity was evaluated using the following markers: total levels of reactive oxygen species (ROS) in blood plasma; catalase activity (CAT) and pro-oxidant/antioxidant ratio in blood haemolysate samples; level of reduced glutathione (GSH) in liver tissues; oxidative modification of proteins, OPM (APHD, aldehyde-dinitrophenylhydrazone derivatives and KPHD, ketone dinitrophenylhydrazone derivatives) and malonic dialdehyde (MDA) in blood plasma and liver samples. Results: AC2 administration promoted significant myeloprotective effect: 1.5-fold increase in leukocytes, 2-fold in neutrophils, 1.5-fold in lymphocytes, and 1.23-fold in platelet count compared to the experimental Melphalan Group. At the same time, AC1 administration resulted in a slight increase in haematological parameters. Both ACs positively corrected important, but diverse, components of oxidative stress. They significantly reduced oxidative modification of blood and liver proteins (especially the AC1 form), normalized the level of reduced glutathione, pro-oxidant/antioxidant ratio and other markers. For some markers, such as ROS production in blood plasma, the use of enterosorbents resulted in non-significant a shift towards normal parameters. Conclusions: Oral activated carbon adsorbents reduce oxidative stress intensity and myelotoxicity; they can be promising means to combat the adverse effects of chemotherapy in clinical practice.

Construction of blood compatible lysine-immobilized chitin/carbon nanotube microspheres and potential applications for blood purified therapy

Novel lysine-immobilized chitin/carbon nanotube microspheres are prepared with excellent bilirubin adsorption properties and good blood compatibility for blood purified therapy.

Polystyrene–divinylbenzene based nano-CaCO3composites for the efficient removal of human tumor necrosis factor-α

PS-DVB/nano-CaCO₃, a novel abundant mesoporous structured polymer nano-composite, exhibits significantly enhanced performances in the adsorption of TNF-α from plasma.

Reduced liver cell death using an alginate scaffold bandage: a novel approach for liver reconstruction after extended partial hepatectomy

Extended partial hepatectomy may be needed in cases of large hepatic mass, and can lead to fulminant hepatic failure. Macroporous alginate scaffold is a biocompatible matrix which promotes the growth, differentiation and long-term hepatocellular function of primary hepatocytes in vitro. Our aim was to explore the ability of implanted macroporous alginate scaffolds to protect liver remnants from acute hepatic failure after extended partial hepatectomy. An 87% partial hepatectomy (PH) was performed on C57BL/6 mice to compare non-treated mice to mice in which alginate or collagen scaffolds were implanted after PH. Mice were scarified 3, 6, 24 and 48 h and 6 days following scaffold implantation and the extent of liver injury and repair was examined. Alginate scaffolds significantly increased animal survival to 60% vs. 10% in non-treated and collagen-treated mice (log rank=0.001). Mice with implanted alginate scaffolds manifested normal and prolonged aspartate aminotransferases and alanine aminotransferases serum levels as compared with the 2- to 20-fold increase in control groups (P<0.0001) accompanied with improved liver histology. Sustained normal serum albumin levels were observed in alginate-scaffold-treated mice 48 h after hepatectomy. Incorporation of BrdU-positive cells was 30% higher in the alginate-scaffold-treated group, compared with non-treated mice. Serum IL-6 levels were significantly decreased 3h post PH. Biotin-alginate scaffolds were quickly well integrated within the liver tissue. Collectively, implanted alginate scaffolds support liver remnants after extended partial hepatectomy, thus eliminating liver injury and leading to enhanced animal survival after extended partial hepatectomy.

An adsorbent monolith device to augment the removal of uraemic toxins during haemodialysis

Adsorbents designed with porosity which allows the removal of protein bound and high molecular weight uraemic toxins may improve the effectiveness of haemodialysis treatment of chronic kidney disease (CKD). A nanoporous activated carbon monolith prototype designed for direct blood contact was first assessed for its capacity to remove albumin bound marker toxins indoxyl sulphate (IS), p-cresyl sulphate (p-CS) and high molecular weight cytokine interleukin-6 in spiked healthy donor studies. Haemodialysis patient blood samples were then used to measure the presence of these markers in pre- and post-dialysis blood and their removal by adsorbent recirculation of post-dialysis blood samples. Nanopores (20-100 nm) were necessary for marker uraemic toxin removal during in vitro studies. Limited removal of IS and p-CS occurred during haemodialysis, whereas almost complete removal occurred following perfusion through the carbon monoliths suggesting a key role for such adsorbent therapies in CKD patient care.

Bio-inspired detoxification using 3D-printed hydrogel nanocomposites

Rationally designed nanoparticles that can bind toxins show great promise for detoxification. However, the conventional intravenous administration of nanoparticles for detoxification often leads to nanoparticle accumulation in the liver, posing a risk of secondary poisoning especially in liver-failure patients. Here we present a liver-inspired three-dimensional (3D) detoxification device. This device is created by 3D printing of designer hydrogels with functional polydiacetylene nanoparticles installed in the hydrogel matrix. The nanoparticles can attract, capture and sense toxins, while the 3D matrix with a modified liver lobule microstructure allows toxins to be trapped efficiently. Our results show that the toxin solution completely loses its virulence after treatment using this biomimetic detoxification device. This work provides a proof-of-concept of detoxification by a 3D-printed biomimetic nanocomposite construct in hydrogel, and could lead to the development of alternative detoxification platforms.