Coenzyme Q10 (CoQ10) is a key component of the mitochondrial electron transfer chain and is one of the most important antioxidants. We previously found that glycoprotein prosaposin (Psap) binds CoQ10 in human cells. Although Psap is expressed in the intestines, its role in the gastrointestinal tract is not clear. To elucidate the role of Psap in the intestines, we established Psap knockdown (KD) Caco-2 cells, which are an intestinal epithelial cell line. Cellular CoQ10 levels decreased significantly in Psap KD Caco-2 cells as compared to parental Caco-2 cells. Cellular ATP levels also decreased significantly in Psap KD Caco-2 cells as compared to parental Caco-2 cells. Lower ATP levels in the intestines have been reported to result in the failure of tight junction formation. As expected, Psap KD Caco-2 monolayers did not produce transepithelial electrical resistance, while parental Caco-2 monolayers did. Moreover, a fluorescent dye, lucifer yellow, leaked out through Psap KD Caco-2 monolayers, whereas it did not through parental Caco-2 monolayers. These results indicate that Psap is essential to maintain cellular levels of CoQ10 and ATP, and consequently to form tight junctions in the gastrointestinal tract.
The generation of hydroxyl radicals and singlet oxygen during the oxidation of 4-(4-hydroxyphenyl)-2-butanol (rhododendrol) and 4-(3,4-dihydroxyphenyl)-2-butanol (rhododendrol-catechol) with mushroom tyrosinase in a phosphate buffer (pH 7.4) was examined as the model for the reactive oxygen species generation via the two rhododendrol compounds in melanocytes. The reaction was performed in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin trap reagents for hydroxyl radical or 2,2,6,6-tetramethyl-4-piperidone (4-oxo-TEMP), an acceptor of singlet oxygen, and their electron spin resonances were measured. An increase in the electron spin resonances signal attributable to the adduct of DMPO reacting with the hydroxyl radical and that of 4-oxo-TEMP reacting with singlet oxygen was observed during the tyrosinase-catalyzed oxidation of rhododendrol and rhododendrol-catechol, indicating the generation of hydroxyl radical and singlet oxygen. Moreover, hydroxyl radical generation was also observed in the autoxidation of rhododendrol-catechol. We show that generation of intermediates during tyrosinase-catalyzed oxidation of rhododendrol enhances oxidative stress in melanocytes.
The glutathione (GSH)-mediated superoxide (O2•−) generation in an aqueous solution and relation of hydrogen peroxide (H2O2) and effect of catalase were investigated. GSH-induced O2•− generation in hyperthermal temperatures was measured by the nitroblue tetrazolium (NBT) mehod. Heating an aqueous solution containing GSH caused superoxide from dissolved O2. H2O2 was generated simultaneously in this reaction mixture probably from the hydroperoxy radical (HO2•), which is equilibrated with O2•− in an aqueous condition, and then H2O2 consumed O2•−. Coexisting catalase in the reaction mixture, as a result, could increase O2•− generation. The catalase-exaggerated extracellular O2•− generation could give a harmful effect to living cells. This GSH-induced oxidative stress can be a part of mechanisms of hyperthermia therapy.
There are evidence that oxidative stress and inflammation are involved in the pathogenesis of the age-related macular degeneration (AMD). The aim of this study was to analyze the antioxidant defense parameters and inflammatory markers in patients with exudative form of AMD (eAMD), their mutual correlations and association with the specific forms of AMD. The cross-sectional study, included 75 patients with the eAMD, 31 patients with the early form, and 87 aged-matched control subjects. Significantly lower SOD, TAS and albumin values and higher GR, CRP and IL-6 were found in the eAMD compared to the early form (p<0.05). Significant negative correlations were found between GPx and fibrinogen (r = –0.254), TAS and IL-6 (r = –0.999) and positive correlations between uric acid and CRP (r = 0.292), IL-6 and uric acid (r = 0.398) in the eAMD. A significant association of CRP (OR: 1.16, 95% CI: 1.03–1.32, p = 0.018), fibrinogen (OR: 2.21, 95% CI: 1.14–4.85, p = 0.021), TAS (OR: 7.45, 95% CI: 3.97–14.35, p = 0.0001), albumin (OR: 1.25, 95% CI: 1.11–1.41, p = 0.0001) and uric acid (OR: 1.006, 95% CI: 1.00–1.02, p = 0.003) was found with the eAMD. In conclusion it may be suggested, there is a significant impairment of antioxidant and inflammatory parameter levels in eAMD patients. In addition, significant association exists between the tested inflammatory markers and antioxidant parameters with late-eAMD.
Black soybean seed coat extract (BE), which contains abundant polyphenols such as procyanidins, cyanidin 3-glucoside, (+)-catechin, and (−)epicatechin, has been reported on health beneficial functions such as antioxidant activity, anti-inflammatory, anti-obesity, and anti-diabetic activities. In this study, we investigated that prevention of BE and its polyphenols on 2,2'-azobis(2-methylpropionamide) dihydrochloride (AAPH)-induced oxidative DNA damage, and found that these polyphenols inhibited AAPH-induced formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker for oxidative DNA damage in HepG2 cells. Under the same conditions, these polyphenols also inhibited AAPH-induced accumulation of reactive oxygen species (ROS) in the cells. Inhibition of ROS accumulation was observed in both cytosol and nucleus. It was confirmed that these polyphenols inhibited formation of AAPH radical using oxygen radical absorbance capacity assay under the cell-free conditions. These results indicate that polyphenols in BE inhibit free radical-induced oxidative DNA damages by their potent antioxidant activity. Thus, BE is an effective food material for prevention of oxidative stress and oxidative DNA damages.
Glutathione, the most abundant intracellular antioxidant, protects cells against reactive oxygen species induced oxidative stress and regulates intracellular redox status. We found that rice peptides increased intracellular glutathione levels in human hepatoblastoma HepG2 cells. Acetaminophen is a commonly used analgesic. However, an overdose of acetaminophen causes severe hepatotoxicity via depletion of hepatic glutathione. Here, we investigated the protective effects of rice peptides on acetaminophen-induced hepatotoxicity in mice. ICR mice were orally administered rice peptides (0, 100 or 500 mg/kg) for seven days, followed by the induction of hepatotoxicity via intraperitoneal injection of acetaminophen (700 mg/kg). Pretreatment with rice peptides significantly prevented increases in serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase levels and protected against hepatic glutathione depletion. The expression of γ-glutamylcysteine synthetase, a key regulatory enzyme in the synthesis of glutathione, was decreased by treatment with acetaminophen, albeit rice peptides treatment recovered its expression compared to that achieved treatment with acetaminophen. In addition, histopathological evaluation of the livers also revealed that rice peptides prevented acetaminophen-induced centrilobular necrosis. These results suggest that rice peptides increased intracellular glutathione levels and could protect against acetaminophen-induced hepatotoxicity in mice.
Carnitine is an essential nutrient for the mitochondrial transport of fatty acids. Carnitine deficiency causes a variety of symptoms in multiple organs. Patients with severe motor and intellectual disabilities often have carnitine deficiency. This study aimed to determine the correlation between constipation and carnitine deficiency in them. Patients with severe motor and intellectual disabilities at our hospital were retrospectively reviewed. The correlation between level of free carnitine and severity of constipation was examined. Constipation and non-constipation groups were compared for age; sex; body mass index; bed rest period; use of anti-epileptic drugs, valproate sodium, or enteral nutrition; and serum levels of albumin, pre-albumin, totalcholesterol, free carnitine, folic acid, and trace elements. Moreover, severity of constipation before and after carnitine supplementation was assessed. Twenty-seven patients were enrolled. Of these, 14 were assigned to the constipation group and 13 to the non-constipation group. The free carnitine level was significantly correlated with severity of constipation (R = 0.7604, p<0.01). Free carnitine was significantly lower in the constipation compared with the non-constipation group (p<0.01). No other significant differences between the groups were found. The severity of constipation was significantly relieved after carnitine supplementation (p<0.001). In conclusion, carnitine supplementation could reduce the severity of constipation.
Accurate assessment of dietary phosphorus intake is necessary to prevent hyperphosphatemia. The aim of this study was to evaluate the 24-h urine collection method for estimation of phosphate intake in healthy males. Two experiments, a 1-day and a 5-day loading test, were performed. After an overnight fast, subjects consumed test meals, 24-h urine collection was performed, and blood samples were obtained. In the 5-day loading test, a phosphorus supplement was orally administered on day 3. The association between the phosphorus content of test meals and urinary excretion, anthropometric indices, and blood biomarkers was analyzed to develop a more precise formula for estimating phosphorus intake. In the 1-day loading test, the standard deviation of predictive phosphorus intake, based on multiple linear regression analysis, was less than that for the phosphorus absorption rate. In the 5-day loading test, urinary phosphorus excretion was similar on days 2, 4 and 5, but was significantly higher on day 3 after phosphorus supplementation. Our results indicate that estimation of dietary phosphorus intake with the 24-h urine collection method, using the amount of phosphorus and urea nitrogen excretion, may increase the precision of short-term monitoring.
The aims of this study were to compare the therapeutic effects of a proton pump inhibitor (PPI), rabeprazole (RPZ), and a prokinetic agent, itopride (ITO), and to investigate the role of PPI in the treatment strategy for Japanese functional dyspepsia (FD) patients. We randomly assigned 134 patients diagnosed by Rome III criteria to 4 weeks treatment with RPZ 10 mg/day (n = 69) or ITO 150 mg/day (n = 65). Dyspeptic symptoms were evaluated using FD scores at baseline and after 1, 2 and 4 weeks of treatment. We also divided subjects into predominantly epigastric pain syndrome (EPS) or postprandial distress syndrome (PDS), and evaluated the efficacy of RPZ and ITO respectively. RPZ showed a significant decrease in the Rate of Change (RC) in FD score within 1 week, which was maintained until after 4 weeks, with RPZ a significant effect compared with ITO at all evaluation points. In addition, RPZ showed a significant decrease in FD score in subjects with both EPS and PDS, whereas a significant decrease in the RC with ITO was only shown in those with predominant PDS. Acid-suppressive therapy with RPZ is useful for PDS as well EPS in Japanese FD patients (UMIN Clinical Trials Registry number: UMIN 000013962).
Maternal folate and vitamin B12 deficiency predict poor pregnancy outcome. To improve pregnancy outcomes in rural area of China, we investigate rural women’s folic acid supplementation (FAS) status and the associations between maternal vitamin B status during the first trimester and subsequent adverse pregnancy outcomes. We collected the questionnaire information and drew 5 ml of blood from 309 early pregnant rural women. The birth outcomes were retrieved from medical records after delivery. Out of the total, 257 had taken FAS, including 50 before conception (group A) and 207 during the first trimester (group B). The concentration of plasma folate and the RBC folate supplementation groups were obviously higher than that of no-supplementation group (group N, p<0.01). The mean vitamin B12 levels in FAS group were significantly higher than those in groups N and B (p<0.05). Women who delivered SGA or premature infants had reduced plasma folate levels (p<0.05) compared with controls. The multiple linear regression models revealed that RBC folate levels affected the infant birth weight (p<0.01) and birth length (p<0.05). In conclusion, FAS can significantly improve plasma folate and RBC folate levels in childbearing-age women and reduce the risk of subsequent adverse pregnancy outcomes.
We investigated the effects of rikkunshito, in combination with a proton pump inhibitor, on symptoms and quality of life in patients with proton pump inhibitor-refractory gastroesophageal reflux disease. The subjects were 47 patients with gastroesophageal reflux disease with residual symptoms such as heartburn following 8 weeks of proton pump inhibitor therapy. We administered these subjects rikkunshito in combination with a proton pump inhibitor for 6–8 weeks. We scored their symptoms of heartburn, fullness, abdominal discomfort, and abdominal pain, and surveyed their quality of life using the Reflux Esophagitis Symptom Questionnaire, comprising questions concerning daily activities, meals (changes in amount and favorite foods), and sleep (getting to sleep and early morning waking). Improvement was seen in all symptoms, and quality of life scores for meals and sleep also improved. These results indicate that combination therapy with rikkunshito and a proton pump inhibitor improves quality of life related to eating and sleep in patients with patients with proton pump inhibitor-refractory gastroesophageal reflux disease.
Intestinal epithelial barrier function is impaired in irritable bowel syndrome patients. Claudins are highly expressed in cells with tight junctions and are involved in the intestinal epithelial barrier function. The expression pattern of tight junction proteins in diarrhea-predominant irritable bowel syndrome have not been fully elucidated. We therefore recruited 17 diarrhea-predominant irritable bowel syndrome patients and 20 healthy controls. The expression of the tight junction-related proteins was examined in the ileal, cecal, and rectal mucosa of diarrhea-predominant irritable bowel syndrome patients using real-time PCR and immunofluorescence. Claudin-2 expression was high in the ileum of diarrhea-predominant irritable bowel syndrome patients. Claudin-2 expression was the same in cecum and rectal mucosa of control and diarrhea-predominant irritable bowel syndrome patients. Similarly, the expression of clauidn-1, claudin-7, JAM-A, occludin, and ZO-1 in the ileal, cecal, and rectal mucosa did not change between control and diarrhea-predominant irritable bowel syndrome samples. Infiltration of eosinophil and mast cells in the mucosa of ileum, cecum and rectum was evaluated using immunohistochemical staining and was not affected by diarrhea-predominant irritable bowel syndrome. Claudin-2 was expressed on the apical side of villi and crypts of ileal mucosal epithelial cells. Clauidn-2 expression is upregulated in diarrhea-predominant irritable bowel syndrome patients and may contribute to the pathogenesis of this condition.
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