Reactive sulfur species, such as cysteine persulfide, are produced endogenously at significant levels in cells and have rapidly emerged as common biomolecules. By virtue of improved analytical methods for detecting reactive persulfides, it has been demonstrated that these reactive molecules exhibit unique chemical properties and are present in various forms in vivo. Accumulating evidence has suggested that persulfides may be involved in a variety of biological processes, such as antioxidant and anti-inflammatory responses, biosynthesis of sulfur-containing molecules, mitochondrial energy metabolism via sulfur respiration, and cytoprotection via regulation of redox signal transduction induced by endogenous and exogenous electrophiles. Elucidation of the persulfide-dependent metabolism of redox signals is expected to facilitate our understanding of the importance of persulfides in regulating redox signals.
The effects of reaction environments on the radical-scavenging mechanisms of ascorbic acid (AscH2) were investigated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) as a reactivity model of reactive oxygen species. Water-insoluble DPPH• was solubilized by β-cyclodextrin (β-CD) in water. The DPPH•-scavenging rate of AscH2 in methanol (MeOH) was much slower than that in phosphate buffer (0.05 M, pH 7.0). An organic soluble 5,6-isopropylidene-l-ascorbic acid (iAscH2) scavenged DPPH• much slower in acetonitrile (MeCN) than in MeOH. In MeOH, Mg(ClO4)2 significantly decelerated the DPPH•-scavenging reaction by AscH2 and iAscH2, while no effect of Mg(ClO4)2 was observed in MeCN. On the other hand, Mg(ClO4)2 significantly accelerated the reaction between AscH2 and β-CD-solubilized DPPH• (DPPH•/β-CD) in phosphate buffer (0.05 M, pH 6.5), although the addition of 0.05 M Mg(ClO4)2 to the AscH2–DPPH•/β-CD system in phosphate buffer (0.05 M, pH 7.0) resulted in the change in pH of the phosphate buffer to be 6.5. Thus, the DPPH•-scavenging reaction by iAscH2 in MeCN may proceed via a one-step hydrogen-atom transfer, while an electron-transfer pathway is involved in the reaction between AscH2 and DPPH•/β-CD in phosphate buffer solution. These results demonstrate that the DPPH•-scavenging mechanism of AscH2 are affected by the reaction environments.
Relatively young (4-week-old) selenium deficient (SeD) mice, which lack the activity of selenium-dependent glutathione peroxidase (GSH-Px) isomers, were prepared using torula yeast-based SeD diet. Mice were fed the torula yeast-based SeD diet and ultra-pure water. Several different timings for starting the SeD diet were assessed. The weekly time course of liver comprehensive GSH-Px activity after weaning was monitored. Protein expression levels of GPx1 and 4 in the liver were measured by Western blot analysis. Gene expression levels of GPx1, 2, 3, 4, and 7 in the liver were measured by quantitative real-time PCR. Apoptotic activity of thymocytes after hydrogen peroxide (H2O2) exposure was compared. Thirty-day survival rates after whole-body X-ray irradiation were estimated. Pre-birth or right-after-birth starting of the SeD diet in dams was unable to lead to creation of SeD mice due to neonatal death. This suggests that Se is necessary for normal birth and healthy growing of mouse pups. Starting the mother on the SeD diet from 2 weeks after giving birth (SeD-trial-2w group) resulted in a usable SeD mouse model. The liver GSH-Px activity of the SeD-trial-2w group was almost none from 4 week olds, but the mice survived for more than 63 weeks. Protein and gene expression of GPx1 was suppressed in the SeD-trial-2w group, but that of GPx4 was not. The thymocytes of the SeD-trial-2w group were sensitive to H2O2-induced apoptosis. The SeD-trial-2w group was sensitive to whole-body X-ray irradiation compared with control mice. The SeD-trial-2w model may be a useful animal model for H2O2/hydroperoxide-induced oxidative stress.
Triptolide (TP) has anti-inflammatory and immunosuppressive effects. However, the effect of triptolide on Sjögren’s syndrome (SS) is rarely reported. In this paper, we studied the effects of triptolide on non-obese diabetes mice model of SS. In this study, salivary flow rate was measured every two weeks, and autoantibodies levels in the serum were detected. Salivary gland index and spleen index were detected, pathological changes of salivary gland were detected by hematoxylin-eosin staining, inflammatory factors were detected by enzyme linked immunosorbent assay, lymphocytes were detected by flow cytometry, proliferation of T cells and B cells were detected, and related proteins were detected by Western blot. Triptolide increased salivary flow rate and salivary gland index, and decreased spleen gland index. Moreover, triptolide reduced the infiltration of lymphocytes to salivary glands, decreased the level of autoantibodies in serum, and reduced the inflammatory factors in salivary glands and IFN-γ induced salivary gland epithelial cells. Further, triptolide inhibited activator of JAK/STAT pathway and NF-κB pathway. In conclusion, triptolide could inhibit the infiltration of lymphocytes and the expression of inflammatory factors through JAK/STAT pathway and NF-κB pathway. Thus, triptolide may be used as a potential drug to treat SS.
Gut bacteria might contribute in early stage of colorectal cancer through the development and advancement of colon adenoma, by which exploring either beneficial bacteria, which are decreased in formation or advancement of colon adenoma and harmful bacteria, which are increased in advancement of colon adenoma may result in implementation of dietary interventions or probiotic therapies to functional means for prevention. Korean fermented kimchi is one of representative probiotic food providing beneficiary microbiota and exerting significant inhibitory outcomes in both APC/Min+ polyposis model and colitis-associated cancer. Based on these backgrounds, we performed clinical trial to document the changes of fecal microbiota in 32 volunteers with normal colon, simple adenoma, and advanced colon adenoma with 10 weeks of fermented kimchi intake. Each amplicon is sequenced on MiSeq of Illumina and the sequence reads were clustered into Operational Taxonomic Units using VSEARCH and the Chao Indices, an estimator of richness of taxa per individual, were estimated to measure the diversity of each sample. Though significant difference in α or β diversity was not seen between three groups, kimchi intake significantly led to significant diversity of fecal microbiome. After genus analysis, Acinobacteria, Cyanobacteria, Clostridium sensu, Turicibacter, Gastronaeophillales, H. pittma were proven to be increased in patients with advanced colon adenoma, whereas Enterococcua Roseburia, Coryobacteriaceau, Bifidobacterium spp., and Akkermansia were proven to be significantly decreased in feces from patients with advanced colon adenoma after kimchi intake. Conclusively, fermented kimchi plentiful of beneficiary microbiota can afford significant inhibition of either formation or advancement of colon adenoma.
Here we investigated the inhibitory effects in rats of mature Citrus unshiu peel (Chenpi) and its component hesperidin on aspirin-induced oxidative damage. The content of hesperidin in Chenpi extract was approximately 11.4%. Wistar rats were orally administered Chenpi extract or hesperidin (20 mg/kg body weight) and then were orally administered aspirin (200 mg/kg body weight) to induce oxidative damage to the stomach, liver, and kidneys. Such damage was evaluated using the formamidopyrimidine DNA glycosylase-modified comet assay. We also measured the amount of the oxidative marker 8-oxo-7,8-dihydroguanine (8-oxodG) in the stomach. Aspirin-induced damage to the gastric mucosa was evaluated using a bleeding score. Chenpi extract and hesperidin significantly inhibited aspirin-induced oxidative DNA damage. The bleeding score of the aspirin-induced gastric mucosa was significantly reduced by treatment with Chenpi extract and hesperidin. To investigate the effects of Chenpi extract and hesperidin on the analgesic effect of aspirin on ddY mice, we employed the acetic acid-induced writhing response test. Chenpi extract and hesperidin did not significantly affect the analgesic effect of aspirin. These results suggest that Chenpi extract and hesperidin significantly inhibit aspirin-induced gastric mucosal damage.
Autophagy-associated genes have been identified as susceptible loci for inflammatory bowel disease. We investigated the role of a core autophagy factor, Atg5, in the development of dextran sodium sulfate (DSS)-induced colitis. Intestinal epithelial cell (IEC)-specific Atg5 gene deficient mice (Atg5ΔIEC mice) were generated by cross of Atg5-floxed mice (Atg5fl/fl) with transgenic mice expressing Cre-recombinase driven by the villin promotor. Mice were given three cycles of 1.5% DSS in drinking water for 5 days and regular water for 14 days over a 60-day period. The dysfunction of autophagy characterized by a marked accumulation of p62 protein, a substrate for autophagy degradation, was detected in epithelial cells in the non-inflamed and inflamed mucosa of inflammatory bowel disease patients. DSS-colitis was exacerbated in Atg5ΔIEC mice compared to control Atg5fl/fl mice. Phosphorylation of inositol-requiring transmembrane kinase/endonuclease1α (IRE1α), a sensor for endoplasmic reticulum stress, and c-Jun N-terminal kinase, a downstream target of IRE1α, were significantly enhanced in IECs in DSS-treated Atg5ΔIEC mice. Accumulation of phosphorylated IRE1α was enhanced by the treatment with chloroquine, an autophagy inhibitor. Apoptotic IECs were more abundant in DSS-treated Atg5ΔIEC mice. These findings suggest that Atg5 suppresses endoplasmic reticulum stress-induced apoptosis of IECs via the degradation of excess p-IRE1α.
Results from a recent study indicate that a higher level of oleic acid/stearic acid ratio was associated with metabolically unhealthy obesity. This was further validated in cross-sectional and interventional studies; however, this was not extensively studied in a non-obese population. We recruited 260 Japanese subjects with serum free fatty acid profiles undergoing anti-aging health examinations. The determinants for oleic acid/stearic acid ratio were investigated using multiple regression analyses. To compare different markers, the subjects were classified based on oleic acid/stearic acid ratio and the combination of oleic acid/stearic acid ratio and triglyceride levels. The oleic acid/stearic acid ratio exhibited a positive correlation with the logmatic transformed triglyceride/high-density lipoprotein cholesterol ratio and the fasting triglycerides-glucose index, both of which were used as markers for insulin resistance. Multiple regression analyses revealed that the triglyceride/high-density lipoprotein cholesterol ratio and fasting triglyceride-glucose index were positively associated with the oleic acid/stearic acid ratio. Most markers were the worst in the highest triglyceride group in both oleic acid/stearic acid groups. In addition, most markers were worse in high oleic acid/stearic acid ratio group than low group. In conclusion, oleic acid/stearic acid ratio might be a useful marker for insulin resistance in non-obese Japanese subjects.
We previously evaluated the antioxidative effects of astaxanthin intake in the aqueous humor by measuring reactive oxygen species-related parameters, including O2•− scavenging activity, H2O2 level, and total hydroperoxides level. In this study, we analyzed the antioxidative effects of astaxanthin in relation to age in 16 males and 19 females (average age 71.3 and 70.6, respectively) who underwent bilateral cataract surgery on one side before and the other side after astaxanthin intake (6 mg/day for 2 weeks). None of the parameters correlated with age before astaxanthin intake, but only total hydroperoxides level was significantly correlated after the astaxanthin intake (r = 0.4, p<0.05). Total hydroperoxides levels were similar in younger and older patients (<70 vs ≥70 years) before astaxanthin, but decreased significantly more in younger patients (–0.21 ± 0.18 vs –0.05 ± 0.31, p<0.05) after the intake, resulting in significantly different levels (p<0.05). The previously observed decrease in mean total hydroperoxides levels following astaxanthin intake was therefore considered likely to be attributable to a greater response in younger subjects. Given that total hydroperoxides levels reflect general antioxidative status, astaxanthin intake may exert a greater antioxidative effect in younger patients. Further comparative studies involving younger subjects and different astaxanthin doses are needed.
There are no reports regarding the efficacy of sodium-glucose cotransporter 2 inhibitor (SGLT2i) and dipeptidyl peptidase 4 inhibitor (DPP4i) administrations in nonalcoholic fatty liver disease (NAFLD) patients without type 2 diabetes mellitus. The purpose of this study was to evaluate the efficacy of those drugs in such patients. NAFLD patients without type 2 diabetes mellitus were enrolled in this single center double-blind randomized prospective study, and allocated to receive either dapagliflozin (SGLT2i) or teneligliptin (DPP4i) for 12 weeks. Laboratory variables and body compositions were assessed at the baseline and end of treatment. The primary endpoint was alanine aminotransferase (ALT) reduction level at the end of treatment. Twenty-two eligible patients (dapagliflozin group, n = 12; teneligliptin group, n = 10) were analyzed. In both groups, the serum concentration of ALT was significantly decreased after treatment (p<0.05). Multiple regression analysis results showed that decreased body weight of patients with dapagliflozin administration was significantly related to changes in total body water and body fat mass. Administration of dapagliflozin or teneligliptin decreased the serum concentration of ALT in NAFLD patients without type 2 diabetes mellitus. With dapagliflozin, body weight decreased, which was related to changes in total body water and body fat mass (UMIN000027304).
Vitamin B6 is an important cofactor in fat metabolism and its deficiency has been correlated with nonalcoholic fatty liver disease. However, no study has investigated the efficacy of vitamin B6 supplementation in these patients. The aim of this open-label, single-arm, single-center study was to examine the therapeutic effect of vitamin B6 in patients with nonalcoholic fatty liver disease. Twenty-two patients with nonalcoholic fatty liver disease received vitamin B6 (90 mg/day) orally for 12 weeks. Clinical parameters were evaluated, and liver fat and fibrosis were quantified before and after treatment using magnetic resonance imaging-based proton density fat fraction and magnetic resonance elastography. Serum alanine aminotransferase levels, the primary endpoint, did not change significantly after vitamin B6 treatment (93.6 ± 46.9 to 93.9 ± 46.6, p = 0.976). On the other hand, magnetic resonance imaging-based proton density fat fraction, a parameter of hepatic lipid accumulation, was significantly reduced (18.7 ± 6.1 to 16.4 ± 6.4, p<0.001) despite no significant changes in body mass index, even in those not taking vitamin E (n = 17, 18.8 ± 6.9 to 16.7 ± 7.3, p = 0.0012). Vitamin B6 administration significantly ameliorated hepatic fat accumulation. As an inexpensive agent with few side effects, vitamin B6 could be a novel therapeutic agent for the treatment of nonalcoholic fatty liver disease.
The number of patients with chronic constipation is increasing in Japan. We investigated the gut mucosa-associated microbiome in Japanese patients with functional constipation. Diagnosis was made according to the Rome IV criteria. Mucosal samples were obtained by gentle brushing of mucosa surfaces. The gut microbiome was analyzed using 16S rRNA gene sequencing. There were no significant differences in bacteria α-diversity such as richness and evenness. The PCoA indicated significant structural differences between the constipation group and healthy controls (p = 0.017 for unweighted and p = 0.027 for weighted). The abundance of the phylum Bacteroidetes was significantly higher in the constipation group. The abundance of the genera Streptococcus, Fusobacterium, Comamonas, and Alistipes was significantly higher in the constipation group. The abundance of the genera Acinetobacter, Oscillospilla, Mucispirillum, Propinibacterium, and Anaerotruncus was significantly lower in the constipation group. In the constipation group, the proportion of genes responsible for sulfur metabolism, selenocompound metabolism, sulfur relay system was significantly higher and the proportion of d-arginine and d-ornithine metabolism and flavonoid biosynthesis was significantly lower. In conclusion, we identified differences of the mucosa-associated microbiome between Japanese patients with functional constipation and healthy controls. The mucosa-associated microbiome of functional constipation was characterized by higher levels of Bacteroidetes (Alistipes).