Journal of Clinical Biochemistry and Nutrition Vol. 59(2016) No. 2

Oral dryness, a serious problem for the aging Japanese society, is induced by aging-related hyposalivation and causes dysphagia, dysgeusia, inadaptation of dentures, and growth of oral Candida albicans. Oxidative stress clearly plays a role in decreasing saliva secretion and treatment with antioxidants such astaxanthin supplements may be beneficial. Therefore, we evaluated the effects of astaxanthin on the oral saliva secretory function of aging mice. The saliva flow increased in astaxanthin-treated mice 72 weeks after administration while that of the control decreased by half. The plasma d-ROMs values of the control but not astaxanthin-treated group measured before and 72 weeks after treatment increased. The diacron-reactive oxygen metabolites (d-ROMs) value of astaxanthin-treated mice 72 weeks after treatment was significantly lower than that of the control group was. The plasma biological antioxidative potential (BAP) values of the control but not astaxanthin-treated mice before and 72 weeks after treatment decreased. Moreover, the BAP value of the astaxanthin-treated group 72 weeks after treatment was significantly higher than that of the control was. Furthermore, the submandibular glands of astaxanthin-treated mice had fewer inflammatory cells than the control did. Specifically, immunofluorescence revealed a significantly large aquaporin-5 positive cells in astaxanthin-treated mice. Our results suggest that astaxanthin treatment may prevent age-related decreased saliva secretion.

Raf-1 kinase inhibitory protein (RKIP) is a critical molecule for cellular responses to stimuli. In this study, we investigated whether RKIP is responsible for neural cell apoptosis induced by oxygen-glucose deprivation (OGD) and explored the role of NF-κB and ERK pathways regulated by RKIP under OGD stimuli. RKIP was overexpressed or knocked down using lentivirus in PC12 cells, which were then challenged by OGD. RKIP overexpression significantly increased the cell viability of OGD cells, and attenuated apoptosis, cell cycle arrest, and reactive oxygen species generation. RKIP knockdown induced reverse effects. Moreover, we found that RKIP interacted with TAK1, NIK, IKK, and Raf-1 and negatively regulated the NF-κB and ERK pathways. RKIP overexpression significantly inhibited IKK, IκBα, and P65 phosphorylation in NF-κB pathway and MEK, ERK, and CREB phosphorylation in ERK pathway, respectively. RKIP knockdown induced reverse effects. Furthermore, a NF-κB inhibitor BAY 11-7082 and a MEK inhibitor U0126 blocked the changes caused by RKIP down-regulation after OGD. In conclusion, these results demonstrate that RKIP plays a key role in neural cell apoptosis caused by OGD partly via regulating NF-κB and ERK pathways. The present study may provide new insights into the role of RKIP in ischemic stroke.

l-Theanine (γ-glutamylethylamide), a component of green tea, is considered to have regulatory and neuroprotective roles in the brain. The present study was designed to determine the effect of l-theanine on excess dopamine-induced neurotoxicity in both cell culture and animal experiments. The primary cultured mesencephalic neurons or co-cultures of mesencephalic neurons and striatal astrocytes were pretreated with l-theanine for 72 h, and then treated with excess dopamine for further 24 h. The cell viability of dopamine neurons and levels of glutathione were evaluated. Excess dopamine-induced neurotoxicity was significantly attenuated by 72 h preincubation with l-theanine in neuron-astrocyte co-cultures but not in neuron-rich cultures. Exposure to l-theanine increased the levels of glutathione in both astrocytes and glial conditioned medium. The glial conditioned medium from l-theanine-pretreated striatal astrocytes attenuated dopamine-induced neurotoxicity and quinoprotein formation in mesencephalic neurons. In addition, replacement of l-glutamate with l-theanine in an in vitro cell-free glutathione-synthesis system produced glutathione-like thiol compounds. Furthermore, l-theanine administration (4 mg/kg, p.o.) for 14 days significantly increased glutathione levels in the striatum of mice. The results suggest that l-theanine provides neuroprotection against oxidative stress-induced neuronal damage by humoral molecules released from astrocytes, probably including glutathione.

Astaxanthin and vitamin E are both effective antioxidants that are frequently used in cosmetics, as food additives, and in to prevent oxidative damage. A combination of astaxanthin and vitamin E would be expected to show an additive anntioxidative effect. In this study, liposomes co-encapsulating astaxanthin and the vitamin E derivatives α-tocopherol (α-T) or tocotrienols (T3) were prepared, and the antioxidative activity of these liposomes toward singlet oxygen and hydroxyl radical was evaluated in vitro. Liposomes co-encapsulating astaxanthin and α-T showed no additive anntioxidative effect, while the actual scavenging activity of liposomes co-encapsulating astaxanthin and T3 was higher than the calculated additive activity. To clarify why this synergistic effect occurs, the most stable structure of astaxanthin in the presence of α-T or α-T3 was calculated. Only α-T3 was predicted to form hydrogen bonding with astaxanthin, and the astaxanthin polyene chain would partially interact with the α-T3 triene chain, which could explain why there was a synergistic effect between astaxanthin and T3 but not α-T. In conclusion, co-encapsulation of astaxanthin and T3 induces synergistic scavenging activity by intermolecular interactions between the two antioxidants.

Resveratrol is a natural polyphenol produced by plants in response to environmental stress. This compound has been shown to have pharmacological effects against a wide range of diseases including neurological, hepatic, cardiovascular and autoimmune conditions. The non-obese diabetic (NOD) mouse, in which loss of lacrimal and salivary gland function occurs, has been studied as an animal model for Sjögren’s syndrome. In this study, we confirmed that administration of resveratrol results in increased secretion of saliva in NOD mice. Although resveratrol enhanced Sirt1 activity, inflammatory cell infiltration was not affected. Moreover, expression of the anti-inflammatory cytokine IL-10 in salivary glands was enhanced in the resveratrol-administered group. Thus, we confirmed a novel therapeutic effect for resveratrol on salivary dysfunction in Sjögren’s syndrome.

To investigate whether gut microbiota is associated with vitamin A nutritional levels in children with persistent diarrhea, a total of 59 pediatric patients with persistent diarrhea aged 1–12 months were selected from the Department of Gastroenterology at the Children’s Hospital of Chongqing Medical University, China. Subjects were hospitalized and divided into VA-deficient (n = 30) and VA-normal (n = 29) groups according to their venous serum retinol levels. Fecal samples from all 59 subjects were collected immediately after admission and analyzed by Illumina MiSeq for 16S rRNA genes to characterize the overall microbiota of the samples. The gut microbiota of the VA-deficient and VA-normal groups were compared using a bioinformatic statistical approach. The Shannon index (p = 0.02), Simpson index (p = 0.01) and component diagram data indicated significantly lower diversity in the VA-deficient than the VA-normal group. A metagenome analysis (LEfSe) and a differentially abundant features approach using Metastats revealed that Escherichia coli and Clostridium butyricum were the key phylotypes of the VA-normal group, while Enterococcus predominated the VA-deficient group. In conclusion, the diversity of gut microbiota and the key phylotypes are significantly different in children with persistent diarrhea at different VA nutritional levels.

This study aimed to investigate the energy metabolism of patients with lung cancer and the relationship between energy metabolism and proinflammatory cytokines. Twenty-eight patients with lung cancer and 18 healthy controls were enrolled in this study. The nutritional status upon admission was analyzed using nutritional screening tools and laboratory tests. The resting energy expenditure and respiratory quotient were measured using indirect calorimetry, and the predicted resting energy expenditure was calculated using the Harris–Benedict equation. Energy expenditure was increased in patients with advanced stage disease, and there were positive correlations between measured resting energy expenditure/body weight and interleukin-6 levels and between measured resting energy expenditure/predicted resting energy expenditure and interleukin-6 levels. There were significant relationships between body mass index and plasma leptin or acylated ghrelin levels. However, the level of appetite controlling hormones did not affect dietary intake. There was a negative correlation between plasma interleukin-6 levels and dietary intake, suggesting that interleukin-6 plays a role in reducing dietary intake. These results indicate that energy expenditure changes significantly with lung cancer stage and that plasma interleukin-6 levels affect energy metabolism and dietary intake. Thus, nutritional management that considers the changes in energy metabolism is important in patients with lung cancer.

Functional gastrointestinal disorders (FGIDs), including functional dyspepsia (FD), are common chronic disorders even in the younger population. Physical activity is advocated for patients with FGIDs, although the evidence is insufficient. We investigated the association between the intensity of regular exercise and gastric emptying to determine the effect of physical activity on dyspeptic symptoms. Thirty healthy individuals were selected and divided into three groups (low, moderate, and high) using the index of total exercise intensity in a week. Gastric emptying was evaluated by the ¹³C-acetate breath test. Gastroesophageal reflux symptoms, dyspeptic symptoms, stool forms, scores of anxiety and depression, and scores of sleep quality were also compared. Baseline scores of gastroesophageal reflux symptoms, anxiety, depression, and sleep quality were not different among the three groups. Gastric emptying was significantly faster in low-intensity exercise group than the moderate-intensity exercise group. Although the presence of loose stool and alcohol consumption were also associated with the intensity of regular exercise, these variables were not confounders. In conclusion, the intensity of regular exercise was independently associated with gastric emptying in healthy individuals. These baseline data would be useful for consideration of an optimal exercise intervention for the treatment of FD.

In this study, we examined the association between soy isoflavones and lipid profiles, apolipoprotein levels in patients with type 2 diabetes in China. The study population was composed of 120 cases (80 women with type 2 diabetes and 40 healthy women). Objects in treatment group received isoflavones 435 mg/day for 2 months, then lipid profiles were analyzed by the colorimetry method and apolipoprotein levels were determined by immune turbidimetric method. And all the indexes were determined after oral glucose tolerance test. The levels of total cholesterol, triglyceride and LDL-C significantly reduced and the levels of HDL-C and apolipoprotein A1 significantly raised in the treatment group after intervention (p<0.05). After oral glucose tolerance test, the level of total cholesterol was lower at postprandial 6 h than at empty stomach in treatment group, it had significantly difference (p<0.05). LDL-C levels in the treatment group not only decreased after intervention, but also was significantly lower at postprandial 4, 6 h than in non-intervention group. The ratio of apolipoprotein A1/apolipoprotein B at postprandial 2 h was the highest after treatment in isoflavone group. Supplementation with 435 mg/day of isoflavones exerted favorable effect on the blood total cholesterol, LDL-C levels and the ratio of apolipoprotein A1/apolipoprotein B in Chinese type 2 diabetes women.

The purpose of this study is to look at these relationships in non-diabetic Korean adults. This study was based on data from the KNHANES V-1, which is representative of the population of Korea. A total of 5,492 participants (≥20 years in age) without type 1 or type 2 diabetes, assessed for serum 25-hydroxyvitamin D [25(OH)D], fasting blood glucose and insulin, as well as anthropometric variables, were included in the analyses. The key study results were as follows: First, vitamin D status [vitamin D deficient, 25(OH)D <25 nM; vitamin D insufficient, 25(OH)D ≥25, <50 nM; vitamin D sufficient, 25(OH)D ≥50 nM] was inversely associated with homeostasis model assessment of insulin resistance (HOMA-IR) and beta cell function (HOMA-B) in model 2 (adjusted for age and gender) and 3 (further adjusted for smoking, alcohol drinking, regular exercise, systolic and diastolic blood pressure, waist circumference, and body mass index). Second, in model 4, when further adjusted for total cholesterol, triglycerides, and HDL-C, vitamin D status was inversely associated with HOMA-B. However, association of vitamin D status and HOMA-IR was no longer significant. In conclusion, vitamin D was inversely associated with beta cell function in non-diabetic Korean adults but was not associated with insulin resistance.

The purpose is to elucidate factors related to negative results of anti-H. pylori antibody test in cases with gastric mucosal atrophy. A total of 859 individuals without past history of eradication therapy for H. pylori (545 males, 314 females; mean age 52.4 years) who underwent an upper GI endoscopy examination and serological test were enrolled as subjects. Serological testing was performed using SphereLight H. pylori antibody J^®, and endoscopic findings of gastric mucosal atrophy by the classification of Kimura and Takemoto and post-eradication findings were analyzed. The positive rates for the anti-H. pylori antibody test in subjects with and without gastric mucosal atrophy were 85.6% and 0.9%, respectively. In analysis of subjects with gastric mucosal atrophy, a low positive rate and serum titer was observed in subjects with C1, C2 and O3 atrophy. When the analysis was performed separately in male and female subjects, low positive rate was observed in males with O3 atrophy and females with C2 atrophy. Suspected post-eradication endoscopic findings were more frequently observed in cases with C2 atrophy. In conclusion, negative result of anti-H. pylori antibody test was frequently observed in middle-aged subjects with C1, C2 and O3 gastric mucosal atrophy.

The aim of this study was to assess the efficacy of esomeprazole-based triple therapy compared with rabeprazole-based triple therapy according to CYP2C19 genotype and clarithromycin susceptibility status for first-line eradication therapy of Helicobacter pylori (H. pylori) in Japan. We enrolled 219 H. pylori-infected patients, and randomly allocated patients to the EAC group (esomeprazole 20 mg, clarithromycin 200 mg, amoxicillin 750 mg for one week, with all drugs given twice daily) or RAC group (rabeprazole 10 mg, clarithromycin 200 mg, amoxicillin 750 mg for one week, with all drugs given twice daily). The H. pylori eradication rate according to the PP analyses was 75.0% (95% CI: 65.2–82.8%) in the EAC group and 71.4% (95% CI: 61.4–79.1%) in the RAC group. There were no statistically significant differences. The eradication rates of the clarithromycin-resistant/-sensitive strains were, respectively, 45.0% (95% CI: 30.7–60.2%)/98.0% (95% CI: 88.7–100%) in the EAC group and 39.5% (95% CI: 25.6–55.3%)/93.5% (95% CI: 81.9–98.4%) in the RAC group. The eradication rate of the clarithromycin-sensitive strains was significantly higher than that of the resistant strains in both groups. In conclusion, EAC and RAC therapies show a comparable efficacy regardless of the CYP2C19 genotype and clarithromycin susceptibility status in Japan.