Short-chain fatty acids bind to apoptosis-associated speck-like protein to activate inflammasome complex to prevent Salmonella infection.

Short-chain fatty acids (SCFAs) produced by gastrointestinal microbiota regulate immune responses, but host molecular mechanisms remain unknown. Unbiased screening using SCFA-conjugated affinity nanobeads identified apoptosis-associated speck-like protein (ASC), an adaptor protein of inflammasome complex, as a noncanonical SCFA receptor besides GPRs. SCFAs promoted inflammasome activation in macrophages by binding to its ASC PYRIN domain. Activated inflammasome suppressed survival of Salmonella enterica serovar Typhimurium (S. Typhimurium) in macrophages by pyroptosis and facilitated neutrophil recruitment to promote bacterial elimination and thus inhibit systemic dissemination in the host. Administration of SCFAs or dietary fibers, which are fermented to SCFAs by gut bacteria, significantly prolonged the survival of S. Typhimurium-infected mice through ASC-mediated inflammasome activation. SCFAs penetrated into the inflammatory region of the infected gut mucosa to protect against infection. This study provided evidence that SCFAs suppress Salmonella infection via inflammasome activation, shedding new light on the therapeutic activity of dietary fiber.

Effects of dietary gelatin hydrolysates on bone mineral density in magnesium-deficient rats.

BACKGROUND: The major types of commercially available gelatin hydrolysates are prepared from mammals or fish. Dietary gelatin hydrolysates from mammals were reported to improve bone mineral density (BMD) in some animal models. In contrast, there is limited study showing the effects of dietary gelatin hydrolysates from fish on BMD. The quantity and structure of peptides in the plasma after oral administration of gelatin hydrolysates depend on the gelatin source, which suggests that the biological activity of gelatin hydrolysates depend on the gelatin source. This study examined the effects of fish-derived gelatin hydrolysate (FGH) or porcine-derived gelatin hydrolysate (PGH) intake on BMD and intrinsic biomechanical properties in magnesium (Mg)-deficient rats as a model showing the decrease in both BMD and intrinsic biomechanical properties. METHODS: Four-week-old male Wistar rats were assigned into four groups: a normal group was fed a normal diet (48 mg Mg/100 g diet), a Mg-deficient (MgD) group was fed a MgD diet (7 mg Mg/100 g diet), a FGH group was fed a MgD + FGH diet (5% FGH), and a PGH group was fed a MgD + PGH diet (5% PGH) for 8 weeks. At the end of the study, BMD and intrinsic biomechanical properties of the femur were measured. RESULTS: The MgD group showed significantly lower Young's modulus, an intrinsic biomechanical property, and trabecular BMD of the femur than the normal group; however, the MgD diet did not affect cortical BMD and cortical thickness. Both the FGH and the PGH groups showed significantly higher cortical thickness and ultimate displacement of the femur than the normal group, but neither type of gelatin hydrolysate affected Young's modulus. Furthermore, the FGH group, but not the PGH group, showed significantly higher trabecular BMD than the MgD group. CONCLUSIONS: This study indicates that FGH and PGH increase cortical thickness but only FGH prevents the decrease in trabecular BMD seen in Mg-deficient rats, while neither type of gelatin hydrolysate affect intrinsic biomechanical properties.

Immediate discontinuation of ablation during pulmonary vein isolation remarkably decreases the incidence of esophageal thermal lesions even when using steerable sheaths.

BACKGROUND: Left atrial-esophageal fistulas (LAEFs) are serious complications with high mortality after atrial fibrillation radiofrequency ablation (AFRA). Decreasing the incidence of esophageal thermal lesions (EsoTLs) that may lead to LAEFs is important. The aim of this study was to suppress EsoTL development and determine the appropriate alarm setting for a temperature-monitoring probe by using steerable sheath (STS) methods. METHODS: We enrolled 82 consecutive patients (mean, 61.9±11.7 years; 75.6% men) who underwent AFRA, including pulmonary vein isolation for symptomatic, drug-refractory atrial fibrillation with esophageal temperature monitoring by using STS between January 2011 and April 2014. All patients underwent upper gastrointestinal endoscopy (UGE) 1-3 days after AFRA. The timing of ablation discontinuation in the first 17 patients was determined by each physician during AFRA (only monitoring group, OM). In the next 65 patients, physicians were to immediately discontinue ablation when an alarm set at 39 °C went off (instruction group, INS). We compared two groups with respect to the incidence of EsoTLs. RESULTS: Among the 82 patients, 5 (6.1%) had EsoTLs after AFRA. EsoTLs occurred in 3 of 17 patients (17.6%) and 2 of 65 patients (3.1%) in the OM and INS groups, respectively. The incidence of EsoTLs in the INS group was significantly lower than that in the OM group (p=0.0254). EsoTL did not occur at maximal temperature less than 39 °C, measured by using esophageal temperature-monitoring probe. CONCLUSIONS: Immediate discontinuation of ablation during pulmonary vein isolation remarkably decreased the incidence of EsoTLs, even when using STS.

Dietary Milk Sphingomyelin Prevents Disruption of Skin Barrier Function in Hairless Mice after UV-B Irradiation.

Exposure to ultraviolet-B (UV-B) irradiation causes skin barrier defects. Based on earlier findings that milk phospholipids containing high amounts of sphingomyelin (SM) improved the water content of the stratum corneum (SC) in normal mice, here we investigated the effects of dietary milk SM on skin barrier defects induced by a single dose of UV-B irradiation in hairless mice. Nine week old hairless mice were orally administrated SM (146 mg/kg BW/day) for a total of ten days. After seven days of SM administration, the dorsal skin was exposed to a single dose of UV-B (20 mJ/cm2). Administration of SM significantly suppressed an increase in transepidermal water loss and a decrease in SC water content induced by UV-B irradiation. SM supplementation significantly maintained covalently-bound ω-hydroxy ceramide levels and down-regulated mRNA levels of acute inflammation-associated genes, including thymic stromal lymphopoietin, interleukin-1 beta, and interleukin-6. Furthermore, significantly higher levels of loricrin and transglutaminase-3 mRNA were observed in the SM group. Our study shows for the first time that dietary SM modulates epidermal structures, and can help prevent disruption of skin barrier function after UV-B irradiation.

Identification of a probiotic bacteria-derived activator of the aryl hydrocarbon receptor that inhibits colitis.

The aryl hydrocarbon receptor (AhR) recognizes environmental xenobiotics and is originally thought to be involved in the metabolism (detoxification) of the substances. Recently, AhR is highlighted as an important regulator of inflammation. Notably, accumulating evidence suggests that activation of the AhR suppresses inflammatory bowel diseases (IBDs). Therefore, non-toxic AhR activators become attractive drug candidates for IBD. This study identified 1,4-dihydroxy-2-naphthoic acid (DHNA), a precursor of menaquinone (vitamin K2) abundantly produced by Propionibacterium freudenreichii ET-3 isolated from Swiss-type cheese, as an AhR activator. DHNA activated the AhR pathway in human intestinal epithelial cell line Caco2 cells and in the mouse intestine. Oral treatment of mice with DHNA induced anti-microbial proteins RegIIIß and γ in the intestine, altered intestinal microbial flora and inhibited dextran sodium sulfate (DSS)-induced colitis, which recapitulated the phenotypes of AhR activation in the gut. As DHNA is commercially available in Japan as a prebiotic supplement without severe adverse effects, DHNA or its derivatives might become a promising drug candidate for IBD via AhR activation. The results also implicate that intestinal AhR might act not only as a sensor for xenobiotics in diet and water but also for commensal bacterial activity because DHNA is a precursor of vitamin K2 produced by vitamin K2-synthesizing commensal bacteria as well as propionic bacteria. Hence, DHNA might be a key bacterial metabolite in the host-microbe interaction to maintain intestinal microbial ecosystem.

Effects of novel TRPA1 receptor agonist ASP7663 in models of drug-induced constipation and visceral pain.

Constipation is a major gastrointestinal motility disorder with clinical need for effective drugs. We previously reported that transient receptor potential ankyrin 1 (TRPA1) is highly expressed in enterochromaffin (EC) cells, which are 5-hydroxytryptamine (5-HT)-releasing cells, and might therefore be a novel target for constipation. Here, we examined the effects of ASP7663, a novel and selective TRPA1 agonist, in constipation models as well as an abdominal pain model. ASP7663 activated human, rat, and mouse TRPA1 and released 5-HT from QGP-1 cells, and oral but not intravenous administration of ASP7663 significantly improved the loperamide-induced delay in colonic transit in mice. While pretreatment with the TRPA1 antagonist HC-030031 and vagotomy both inhibited the ameliorating effect of oral ASP7663 on the colonic transit, both orally and intravenously administered ASP7663 significantly inhibited colorectal distension (CRD)-induced abdominal pain response in rats. Taken together, these results demonstrate that ASP7663 exerts both anti-constipation and anti-abdominal pain actions, the former is likely triggered from the mucosal side of the gut wall via activation of vagus nerves while the latter is assumed to be provoked through systemic blood flow. We conclude that ASP7663 can be an effective anti-constipation drug with abdominal analgesic effect.

Strain-specific identification of Bifidobacterium bifidum OLB6378 by PCR.

The aim of the present study was to develop a strain-specific polymerase chain reaction (PCR) primer set for the detection of Bifidobacterium bifidum OLB6378 (OLB6378) that can serve as suitable probiotics for infants. The random amplified polymorphic DNA (RAPD)-PCR technique was used to obtain OLB6378-specific PCR products. One OLB6378-specific RAPD-PCR product was obtained after testing 97 RAPD primers, and was sequenced. Thirteen PCR primer sets were designed from the sequence. One PCR primer set was found to amplify one PCR product when genomic DNA of OLB6378 was used as template. The primer set did not amplify any PCR product when the other genomic DNA was used as template. The primer set was tested with 47 strains of B. bifidum and 20 strains of the other Bifidobacterium species. As a result, we developed an OLB6378-specific primer set, one that should be useful not only for the detection of OLB6378 but also for the quantification of OLB6378.

Prolonged paced QRS duration as a predictor for congestive heart failure in patients with right ventricular apical pacing.

BACKGROUND: The recent studies showed that right ventricular (RV) pacing was associated with worsening of heart failure. The aim of this study is to clarify the clinical significance of paced QRS duration during RV pacing to predict congestive heart failure (CHF) patients. METHODS AND RESULTS: This study enrolled in 92 patients with atrioventricular block who underwent initial pacemaker implantation. The paced QRS duration was automatically obtained by electrocardiography immediately after pacemaker implantation and then by routine attendance at a pacemaker clinic every 3 months. The paced QRS duration was positively correlated with left ventricular end-diastolic dimension (P < 0.05) and left ventricular end-systolic dimension (P < 0.05), and tended to negatively correlate with left ventricular ejection fraction (P = 0.0507). The paced QRS duration immediately after pacemaker implantation was 170.4 +/- 18.9 ms. During a mean follow-up period of 53 +/- 16 months, 16 patients developed CHF. We selected as a cut-off value the nearest whole number (190 ms) that was one standard deviation greater than the mean, and divided into two groups according to baseline paced QRS duration. Patients with a paced QRS duration of <190 ms comprised group A (n = 77, nine of which developed CHF) and the remainder comprised group B (n = 15, seven of which developed CHF). Prolonged paced QRS duration (> or =190 ms) was associated with a significant increase in the overall morbidity of CHF (P < 0.05). Additionally, paced QRS duration significantly prolonged during the follow-up period among group A patients with CHF (P < 0.05), but did not change among patients without CHF. CONCLUSION: We concluded that paced QRS duration can be a useful indicator of impaired left ventricular function in patients with RV pacing. Even in patients whose paced QRS duration is relatively shorter, progressive prolongation of paced QRS duration can predict the development of CHF.

A new synthetic method for alpha-alkoxycarbonyl iminium salt and its reaction with nucleophiles.

An iminium salt was easily prepared using the oxidation of amino ketene silyl acetal with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and the subsequent nucleophilic addition to this iminium species proceeded efficiently to afford alpha-amino esters in good yields.