Here we studied cerium oxide nanoparticles (nanoceria) as an agent for the future treatment of oxidative damage by validating and evaluating its scavenging activity towards reactive oxygen species (ROS) in vitro. Nanoceria has been shown to mimic the activities of superoxide dismutase and catalase, degrading superoxide (O₂^•−) and hydrogen peroxide (H₂O₂). We examined the antioxidative activity of nanoceria, focusing on its ability to quench singlet oxygen (¹O₂) in an aqueous solution. Electron paramagnetic resonance (EPR) was used to determine the rates of second-order reactions between nanoceria and three ROS (¹O₂, O₂^•−, and H₂O₂) in aqueous solution, and its antioxidative abilities were demonstrated. Nanoceria shows a wide range of ultraviolet-light absorption bands and thus ¹O₂ was produced directly in a nanoceria suspension using high-frequency ultrasound. The quenching or scavenging abilities of nanoceria for ¹O₂ and hypoxanthine-xanthine oxidase reaction-derived O₂^•− were examined by EPR spin-trapping methods, and the consumption of H₂O₂ was estimated by the EPR oximetry method. Our results indicated that nanoceria interact not only with two previously reported ROS but also with ¹O₂. Nanoceria were shown to degrade O₂^•− and H₂O₂, and their ability to quench ¹O₂ may be one mechanism by which they protect against oxidative damage such as inflammation.

We used cold atmospheric pressure plasma jet to examine in detail ¹O₂ generation in water. ESR with 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide, a secondary amine probe, was used for the detection of ¹O₂. Nitroxide radical formation was detected after cold atmospheric pressure plasma jet irradiation of a 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide solution. An ¹O₂ scavenger/quencher inhibited the ESR signal intensity induced by cold atmospheric pressure plasma jet irradiation, but this inhibition was not 100%. As 2,2,5,5-tetramethyl-3-pyrroline-3-carboxamide reacts with oxidizing species other than ¹O₂, it was assumed that the signal intensity inhibited by NaN₃ corresponds to only the nitroxide radical generated by ¹O₂. The concentration of ¹O₂ produced by cold atmospheric pressure plasma jet irradiation for 60 ‍s was estimated at 8 ‍μM. When this ¹O₂ generation was compared to methods of ¹O₂ generation like rose bengal photoirradiation and 4-methyl-1,4-etheno-2,3-benzodioxin-1(4H)-propanoic acid (endoperoxide) thermal decomposition, ¹O₂ generation was found to be, in decreasing order, rose bengal photoirradiation ≥ cold atmospheric pressure plasma jet > endoperoxide thermal decomposition. Cold atmospheric pressure plasma jet is presumed to not specifically generate ¹O₂, but can be used to mimic states of oxidative stress involving multiple ROS.

This study aimed to illustrate the dose-response relationships of the direct scavenging activity of amide-based local anesthetics against multiple free radicals in vitro. We have demonstrated that amide-type local anesthetics selectively and directly scavenge some free radicals. Three kinds of free radicals were eliminated by all the four local anesthetics examined. Mepivacaine, lidocaine, bupivacaine, and dibucaine scavenged hydroxyl radicals in dose-dependent manners. Ascorbyl free radicals were also scavenged in ‍dose-dependent manners, and lastly singlet oxygen was scavenged in dose-dependent manners. Three other free radicals were not scavenged by all of the four local anesthetics; tert-butoxyl radical was scavenged by all the anesthetics examined but dibucaine, nitric oxide by mepivacaine but not by the other three, and tyrosyl radical by mepivacaine and lidocaine but not by the other two. Some free radicals (superoxide anion, tert-butyl peroxyl radical, DPPH) were not scavenged by any of the four local anesthetics. The local anesthetics were also shown to inhibit lipid peroxidation by TBARS assay. These results suggest that local anesthetics have antioxidant properties through their free radical scavenging activities.

Reactive oxygen species are considered a cause of neuronal cell death in Alzheimer’s disease (AD). Abnormal tau phosphorylation is a proven pathological hallmark of AD. Microtubule affinity-regulating kinases (MARKs) regulate tau-microtubule binding and ‍play a crucial role in neuronal survival. In this study, we hypothesized that oxidative stress increases the phosphorylation of Ser262 of tau protein through activation of MARKs, which is the main reason for the development of AD. We investigated the relationship between tau hyperphosphorylation on Ser262 and MARKs in N1E-115 cells subjected to oxidative stress by exposure to a low concentration of hydrogen peroxide. This work builds on the observation that hyperphosphorylation of tau is significantly increased by oxidative stress. MARKs activation correlated with tau hyperphosphorylation at Ser262, a site that is essential to maintain microtubule stability and is the initial phosphorylation site in AD. These results indicated that MARKs inhibitors might serve a role as therapeutic tools for the treatment of AD.

Cancer cachexia is commonly seen in patients with malignant tumors, which usually leads to poor life quality and negatively affects long-term prognosis and survival. Mitochondria dysfunc­tion and enhanced autophagy are well-established to play an important role in skeletal muscle wasting. However, whether mitophagy is engaged in the pathogenesis of cancer cachexia requires further investigation. This study comprised a clinical study and animal experimentation. Clinical data such as CT images and laboratory results were obtained and analyzed. Then mice model of cancer cachexia and mitophagy inhibition were established. Data including skeletal muscle mass and function, mitochondria structure and function, inflammatory factors as well as ROS concentration. Mitophagy was enhanced in cancer cachexia patients with increased inflammatory factors. Greater disruption of skeletal muscle fiber and mitochondria structure were seen in cancer cachexia, with a higher level of inflammatory factors and ROS expression in skeletal muscle. Meanwhile, ATP production was undermined, indicating a close relationship with mitophagy, inflammation, and oxidative stress in the skeletal muscle of cancer cachexia mice models. In conclusion, mitophagy is activated in cancer cachexia and may play a role in skeletal muscle atrophy, and inflammation and oxidative stress might participate in mitophagy-related skeletal muscle injury.

The G protein-coupled receptor, class C, group 5, member A (GPRC5A) plays a key role in various diseases, but its effect on hepatocellular carcinoma (HCC) and the potential underlying mechanisms remains unclear. In the present study, we explored the effect of GPRC5A on the progression of HCC and further explored its mechanism of action. The results revealed that the expression of GPRC5A was lower in HCC tissues and cells. Overexpression of GPRC5A suppressed the proliferation and epithelial-mesenchymal transition (EMT) of HCC cells. In addition, overexpression of GPRC5A induced oxidative stress and apoptosis. Further study showed that overexpression of GPRC5A inhibited the expression of STAT3/Socs3/c-‍MYC related-protein and the NLRP3 inflammasome. Moreover, the STAT3/Socs3/c-‍MYC and NLRP3 inflammasome was involved in the effect of GPRC5A on HCC cells. These results suggest that GPRC5A suppresses proliferation and EMT, induces oxidative stress and leads to apoptosis of HCC cells, potentially by regulating STAT3/Socs3/c-‍MYC signalling and the NLRP3 inflammasome. These findings suggest that GPRC5A has an anti-tumor effect in the formation of HCC, and the molecular therapy of GPRC5A provides a theoretical basis for treating HCC.

NAD(P)H-dependent quinone oxidoreductase (NQO) is an essential enzyme in living organisms and cells protecting them from oxidative stress. NQO reduces coenzyme Q (CoQ) using NAD(P)H as an electron donor. In the present study, we searched for coenzyme Q10 reducing activity from fractions of gel filtration-fractionated rat liver homogenate. In addition to the large-molecular-weight fraction containing NQO, CoQ10 reducing activity was also detected in a low-molecular-weight fraction. Furthermore, dicumarol, a conventional inhibitor of NQO1 (DT diaphorase), did not inhibit the reduction but quercetin did, suggesting that the activity was not due to NQO1. After further purification, the NADH-dependent CoQ10-reducing compound was identified as riboflavin. Riboflavin is an active substituent of other flavin compounds such as FAD and FMN. These flavin compounds also reduced not only CoQ homologues but also vitamin K homologues in the presence of NADH. The mechanism was speculated to work as follows: NADH reduces flavin compounds to the corresponding reduced forms, and subsequently, the reduced flavin compounds immediately reduce bio-quinones. Furthermore, the flavin-NADH system reduces CoQ10 bound with saposin B, which is believed to function as a CoQ transfer protein in vivo. This flavin-dependent CoQ10 reduction, therefore, may function in aqueous phases such as the cell cytosol and bodily fluids.

High-fat consumption promotes the development of obesity, which is associated with various chronic illnesses. Mitochondria are the energy factories of eukaryotic cells, maintaining self-stability through a fine-tuned quality-control network. In the present study, we evaluated high-fat diet (HFD)-induced changes in mitochondrial ultrastructure and dynamics protein expression in multiple organs. C57BL/6J male mice were fed HFD or normal diet (ND) for 24 weeks. Compared with ND-fed mice, HFD-fed mice exhibited increased body weight, cardiomyocyte enlarge­ment, pulmonary fibrosis, hepatic steatosis, renal and splenic structural abnormalities. The cellular apoptosis of the heart, liver, and kidney increased. Cellular lipid droplet deposition and mitochondrial deformations were observed. The proteins related to mitochondrial biogenesis (TFAM), fission (DRP1), autophagy (LC3 and LC3-II: LC3-I ratio), and mitophagy (PINK1) presented different changes in different organs. The mitochondrial fusion regulators mitofusin-2 (MFN2) and optic atrophy-1 (OPA1) were consistently downregulated in multiple organs, even the spleen. TOMM20 and ATP5A protein were enhanced in the heart, skeletal muscle, and spleen, and attenuated in the kidney. These results indicated that high-fat feeding caused pathological changes in multiple organs, accompanied by mitochondrial ultrastructural damage, and MFN2 and OPA1 downregulation. The mitochondrial fusion proteins may become promising targets and/or markers for treating metabolic disease.

Compositional changes in the microbiota are associated with various inflammatory diseases, including ulcerative colitis (UC). Aim: This study aimed to investigate the mucosa-associated microbiota (MAM) in patients with UC and its difference related with disease activity and classification. Brush samples were collected from the terminal ileum and sigmoid colon during endoscopic procedures. The microbiota of samples was profiled using the Illumina MiSeq platform. The V3–V4 regions of the gene encoding 16S rRNA (460 bp) were amplified using PCR. Fifty UC patients and twenty healthy controls were enrolled. UC patients displayed significantly reduced α-diversity in both the ileum and sigmoid colon compared to controls. A difference in β-diversity in the unweighted analysis was observed between the two groups. The abundance of Lactobacillus and Veillonella was significantly higher and that of Butyricicoccus, Ruminococcus and Lachnospiraceae was significantly lower in the ileum of UC patients than in controls. The abundance of Odoribacter in the ileum was significantly lower in left-sided colitis and pancolitis patients than in proctitis patients and lower in patients with highly severe disease activity than with mild disease activity. The reduction in abundance of butyric acid-producing bacteria, especially Odoribacter, in ileal MAM may play an important role in the pathophysiology of UC.

Detailed evaluations of body mass index (BMI) and stool form based on the Bristol Stool Form Scale (BSFS) in individuals with ‍constipation, gastroesophageal reflux disease (GERD), and concomitant constipation and GERD have not been performed in Japan. This study was an internet survey conducted to examine the relationships between BMI and constipation, GERD, stool forms based on the BSFS, and education level. This internet-based survey recruited participants from general public survey panels. 10,000 individuals meeting the eligibility criteria were enrolled. Questions included demographics, medical data, and assessments based on validated measures for constipation and GERD. BMI was significantly lower in males with versus without constipation. BMI was significantly higher with GERD both males and females. Mean BMI increased from the BSFS-1/2 group through the BSFS-3/4/5 to the BSFS-6/7 groups in both sexes. BMI was highest in individuals with a maximum education level of junior high school and second highest in individuals completing high school. This is the first real-world survey that closely examines the relationship between BMI and stool forms of individuals in Japan. When the BMI increased, stool forms varied from hard to watery in Japanese people. BMI was related with education level in Japan. (Trial registration: UMIN000039688)

The prevalence of chronic constipation in Japan is increasing, and is presently almost 1 in 5 people. Because constipation is common, especially in older patients, to avoid adverse events and poly­pharmacy, simple treatments at low doses are generally desired. Although the chloride channel activator lubiprostone is candidate drug that may solve these problems, factors associated with the long-term efficacy of lubiprostone monotherapy for chronic constipation in treatment-naive patients remain unclear. We here retrospectively investigated the clinical characteristics and factors of patients who achieved long-term constipation improvement with lubiprostone monotherapy. Seventy-four patients with chronic constipation treated with lubiprostone monotherapy (24 or 48 ‍μg/day) from January 2017 to August 2018 were reviewed. Patient characteristics and clinical time-courses were compared between those who sustained improvement for 6 months, and ‍those who became refractory to treatment. In 54 patients (76.1%), constipation improved by lubiprostone administration for 6 months. On multivariate analysis, a significant clinical factor ‍associated with sustained improvement was a starting lubiprostone dose of 24 ‍μg/day (odds ratio: 5.791; 95% confidence interval: 1.032–32.498; p = 0.046). A starting lubiprostone dose of 24 ‍μg/day has efficacy to improve chronic constipation and to prevent adverse events of nausea and diarrhea in Japanese patients.

Traumatic brain injury is one of the major causes of morbidity and ‍mortality worldwide. With the development of bile acids as a ‍potential treatment, to identify the influence of traumatic brain ‍injury on bile acid metabolism shows growing importance. This present study did a preliminary exploration of the bile acid ‍profile alteration among traumatic brain injury patients. In total, 14 patients and 7 healthy volunteers were enrolled. The bile ‍acid profile of the blood samples were detected by an Ultra-‍performance Liquid Chromatography Mass Spectrometer/Mass Spectrometer system. It was found that 6 bile acids were statistically decreased in traumatic brain injury patients comparing with healthy volunteers: glycocholic acid (median level 44.4 ng/ml vs 98.7 ng/ml, p = 0.003), taurocholic acid (median level 10.9 ng/ml vs 19.5 ng/ml, p = 0.006), glycoursodeoxycholic acid (median level 17.4 ng/ml vs 71.4 ng/ml, p = 0.001), ursodeoxycholic acid (median level <1 ng/ml vs 32.4 ng/ml, p = 0.002), taurochenodeoxycholic acid (median level <1 ng/ml vs 53.6 ng/ml, p = 0.003) and glycochenodeoxycholic acid (GCDCA, median level 160 ng/ml vs ‍364 ng/ml, p<0.001). In conclusion, traumatic brain injury events are able to induce bile acid metabolism alteration in plasma and might cause reduction in glycocholic, taurocholic, glycoursodeoxycholic, ursodeoxycholic, taurochenodeoxycholic and glycochenodeoxycholic acid levels.