Feasibility exploration of GSH in the treatment of acute hepatic encephalopathy from the aspects of pharmacokinetics, pharmacodynamics, and mechanism.

Our previous study highlighted the therapeutic potential of glutathione (GSH), an intracellular thiol tripeptide ubiquitous in mammalian tissues, in mitigating hepatic and cerebral damage. Building on this premise, we posited the hypothesis that GSH could be a promising candidate for treating acute hepatic encephalopathy (AHE). To verify this conjecture, we systematically investigated the feasibility of GSH as a therapeutic agent for AHE through comprehensive pharmacokinetic, pharmacodynamic, and mechanistic studies using a thioacetamide-induced AHE rat model. Our pharmacodynamic data demonstrated that oral GSH could significantly improve behavioral scores and reduce hepatic damage of AHE rats by regulating intrahepatic ALT, AST, inflammatory factors, and homeostasis of amino acids. Additionally, oral GSH demonstrated neuroprotective effects by alleviating the accumulation of intracerebral glutamine, down-regulating glutamine synthetase, and reducing taurine exposure. Pharmacokinetic studies suggested that AHE modeling led to significant decrease in hepatic and cerebral exposure of GSH and cysteine. However, oral GSH greatly enhanced the intrahepatic and intracortical GSH and CYS in AHE rats. Given the pivotal roles of CYS and GSH in maintaining redox homeostasis, we investigated the interplay between oxidative stress and pathogenesis/treatment of AHE. Our data revealed that GSH administration significantly relieved oxidative stress levels caused by AHE modeling via down-regulating the expression of NADPH oxidase 4 (NOX4) and NF-κB P65. Importantly, our findings further suggested that GSH administration significantly regulated the excessive endoplasmic reticulum (ER) stress caused by AHE modeling through the iNOS/ATF4/Ddit3 pathway. In summary, our study uncovered that exogenous GSH could stabilize intracerebral GSH and CYS levels to act on brain oxidative and ER stress, which have great significance for revealing the therapeutic effect of GSH on AHE and promoting its further development and clinical application.

Therapeutic potential of the topical recombinant human interleukin-1 receptor antagonist in guinea pigs with allergic rhinitis.

BACKGROUND: Recombinant human Interleukin receptor antagonist (rhIL-Ra) can bind to the IL-1 receptor on the cell membrane and reversibly blocks the proinflammatory signaling pathway. However, its effect on allergic rhinitis (AR) and the underlying mechanism remains unknown. This study aims to investigate the efficacy of recombinant human interleukin-1 receptor antagonist (rhIL-1Ra) on AR guinea pigs. METHODS: Guinea pigs were systemically sensitized by intraperitoneal injection and topical intranasal instillation with ovalbumin within 21 days. Animals administrated with saline served as the normal control. The AR animals were randomly divided into the model group and distinct concentrations of rhIL-1Ra and budesonide treatment groups. IL-1ß and ovalbumin specific IgE levels were detected by ELISA kits. Nasal mucosa tissues were stained with hematoxylin & eosin (HE) for histological examination. RESULTS: It was found that the numbers of sneezing and nose rubbing were remarkably reduced in rhIL-1Ra and budesonide-treated guinea pigs. Besides, rhIL-1Ra distinctly alleviated IgE levels in serum and IL-1ß levels in nasal mucus, together with decreased exfoliation of epithelial cells, eosinophilic infiltration, tissue edema and vascular dilatation. CONCLUSIONS: rhIL-1Ra is effective in AR guinea pigs and may provide a novel potential choice for AR treatments.

Identification and Validation of Active Ingredient in Cerebrotein Hydrolysate-I Based on Pharmacokinetic and Pharmacodynamic Studies.

Cerebrotein hydrolysate-1 (CH-1), a mixture of small peptides, polypeptides, and various amino acids derived from porcine brain, has been widely used in the treatment of cerebral injury. However, the bioactive composition and pharmacokinetics of CH-1 are still unexplored because of their complicated composition and relatively tiny amounts in vivo. Herein, NanoLC Orbitrap Fusion Lumos Tribrid Mass Spectrometer was firstly used to qualitatively analyze the components of CH-1. A total of 1347 peptides were identified, of which 43 peptides were characterized by high mass spectrometry (MS) intensity and identification accuracy. We then innovatively synthesized four main peptides for activity verification, and the results suggested that Pep72 (NYEPPTVVPGGDL) had the strongest neuroprotective effect on both in vivo and in vitro models. Next, a quantitative method for Pep72 was established based on liquid chromatography tandem mass spectrometry (LC-MS/MS) with the aid of Skyline software and then used in its pharmacokinetic studies. The results revealed that Pep72 had a high elimination rate and low exposure in rats. In addition, a hCMEC/D3-based in vitro model was built and firstly used to investigate the transport of Pep72. We found that Pep72 had extremely low blood-brain barrier permeability and was not a substrate of efflux transporters. The biotransformation of Pep72 in rat fresh plasma and tissues was investigated to explore the contradiction between pharmacokinetics and efficacy. A total of 11 main metabolites were structurally identified, with PGGDL and EPPTVPGGDL being the main metabolites of Pep72. Notably, metalloproteinase and cysteine protease were confirmed to be the main enzymes mediating Pep72 metabolism in rat tissues. SIGNIFICANCE STATEMENT: The NanoLC Orbitrap Fusion Lumos Tribrid Mass Spectrometer was firstly applied to discover the components of CH-1, and one main peptide Pep72 (NYEPPTVVPGGDL) was innovatively synthesized and firstly found to have the strongest neuroprotective effect among 1347 peptides identified from CH-1. Our study is the first time to identify and verify the active ingredient of CH-1 from the perspective of pharmacokinetics and pharmacodynamics, and provides a systematic technical platforms and strategies for the active substance research of other protein hydrolysates.

Kojic acid protects C57BL/6 mice from gamma-irradiation induced damage.

The radioprotective effects of a single administration of kojic acid (KA) against ionizing radiation were evaluated via assessment of 30-day survival and alterations of peripheral blood parameters of adult C57BL/6 male mice. The 30-day survival rate of mice pretreated with KA (75 or 300 mg/kg body weight, KA75 or KA300) subcutaneously 27 h prior to a lethal dose (8 Gy, 153.52 cGy/min) of gamma irradiation was higher than that of mice irradiated alone (40% or 60% vs 0%). It was observed that the white blood cell (WBC) count/the red blood cell (RBC) count, haemoglobin content, haematocrit and platelet count of mice with or without KA pretreatment as exposed to a sub-lethal dose (4 Gy, 148.14 cGy/min) of gamma irradiation decreased maximally at day 4/day 8 post-irradiation. Although the initial WBC values were low in KA300 or WR-2721 (amifostine) groups, they significantly recovered to normal at day 19, whereas in the control group they did not. The results from the cytotoxicity and cell viability assays demonstrated that KA could highly protect Chinese hamster ovary (CHO) cells against ionizing radiation with low toxicity. In summary, KA provides marked radioprotective effects both in vivo and in vitro.