Assessing Immunogenicity in Drug Reviews and Prescribing Information in Japan.

Anti-drug antibodies (ADAs) generated in response to biopharmaceuticals can significantly impact pharmacokinetics (PK) and overall drug efficacy. Thus, the ICH M4 guidelines mandate summarizing immunogenicity data from clinical trials in drug approval applications. However, following the approval of the first antibody drug in Japan in 2001, no cross-sectional investigation has focused on immunogenicity during the regulatory review process. Therefore, this study aims to examine the review reports and prescribing information of antibody drugs approved in Japan to identify key points related to immunogenicity evaluation. We conducted a cross-sectional analysis of review reports for antibody drugs approved between June 2001 and July 2022 by the Japanese regulatory authority. Specifically, we evaluated the ADA positivity rate, presence of neutralizing antibodies, antibody titers, and effects of ADA on PK, efficacy, and safety. We also compared this information with that provided in the prescribing information. Our analysis revealed that the ADA positivity rate and its effects on PK, efficacy, and safety were critical aspects of the review process. The emphasis on these factors varied depending on the number of applications and disease area. The information presented in the prescribing information was largely consistent with that discussed in the review reports. Overall, this study provides the first cross-sectional evaluation of immunogenicity considerations in the regulatory review of antibody drugs in Japan. Our findings can contribute to the efficiency of clinical trial planning and preparation of approval applications, to potentially improve the overall drug development process and address the drug loss problem in Japan.

Safety, pharmacokinetics, and pharmacodynamics of ART-648, a PDE4 inhibitor in healthy subjects: A randomized, placebo-controlled phase I study.

Phosphodiesterase 4 (PDE4) inhibitor is associated with a broad-spectrum anti-inflammatory mechanism. However, securing clinically efficacious doses with sufficient safety margins remains challenging due to class specific adverse events that are often unavoidable in the clinic. ART-648 is an orally available PDE4 inhibitor being developed for the treatment of inflammatory diseases. According to the estimated clinical doses based on an in vitro whole-blood assay, a phase I study was designed. The purpose of this phase I study was to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) following single and multiple administration of ART-648 in healthy subjects. PD was assessed by suppression of lipopolysaccharide-induced TNFα release in ex vivo whole-blood assay. In the single rising dose study, ART-648 was safe and well tolerated with a dose-proportional increase in exposures up to 4 mg. Single doses of ART-648 demonstrated dose-dependent PD response, indicating target engagement at 2-8 mg doses. In the multiple rising dose study, doses up to 4 mg BID after careful titration were well tolerated, while doses up to 6 mg BID were tolerated not in all but the majority of subjects. In conclusion, ART-648 exhibits a favorable PK profile with robust target engagement at clinically safe and tolerated doses identified in healthy subjects.

Cadence-Based Pedometer App With Financial Incentives to Enhance Moderate-to-Vigorous Physical Activity: Development and Single-Arm Feasibility Study.

BACKGROUND: High levels of physical activity are key to improving health outcomes, yet many people fail to take action. Using pedometers to target steps per day and providing financial incentives is a simple and scalable approach to promoting public health. However, conventional pedometers do not account for "intensity" and "duration," making it challenging to efficiently increase people's moderate-to-vigorous physical activity (MVPA), which is expected to improve health outcomes. Based on these rationales, we developed a smartphone app that sets step cadence as a goal (defined as a daily challenge of walking more than 1500 steps in 15 minutes twice a day, which is a heuristic threshold for moderate physical activity) and provides financial incentive when the challenge is met. OBJECTIVE: This study aimed to evaluate the feasibility of our novel app and explore whether its use can increase users' daily MVPA. METHODS: A single-arm pre-post study evaluated the feasibility and efficacy of the app. A total of 15 participants used app 1 (an app without financial incentives) for the first period (4 weeks) and then switched to app 2 (an app with financial incentives) for the second period (4 weeks). The primary outcome was the difference between the first and second periods in the number of successful challenge attempts per week. Secondary outcomes were differences between the first and second periods in daily steps and distance walked. Exploratory outcomes included the difference between the first and second periods in daily "heart points" as measured by Google Fit, a publicly available app that measures users' daily MVPA. RESULTS: The number of successful challenge attempts per week increased significantly compared to the first period (5.6 times per week vs 0.7 times per week; P<.001). Although not statistically significant, there was a trend toward an increase in the mean steps per day and distance walked per day (6586 steps per day vs 5950 steps per day; P=.19; and 4.69 km per day vs 3.85 km per day; P=.09, respectively). An exploratory end point examining daily MVPA by "heart points" collected from Google Fit also showed a significant increase compared to the first period (22.7 points per day vs 12.8 points per day; P=.02). CONCLUSIONS: Our app using step cadence as a goal and providing financial incentives seemed feasible and could be an effective app to increase users' daily MVPA. Based on the results of this study, we are motivated to conduct a confirmatory study with a broader and larger number of participants. TRIAL REGISTRATION: UMIN 000050518; https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000057420.

Flecainide Toxicity From Clinical Pharmacology Perspectives.

We report a case comparing the measured half-life of flecainide with the half-life stated on the label. An 84-year-old woman presented with symptoms of anorexia and exertional dyspnea. She had undergone mitral and aortic valve replacements and excision of the membranous septum in the atrium for mitral and aortic stenosis and cor triatriatum. She was regularly administered 100 mg/day flecainide for paroxysmal atrial fibrillation. A previous electrocardiogram (ECG) showed a regular sinus rhythm. However, upon admission, the ECG revealed a heart rate of 94 bpm and an accelerated idioventricular rhythm originating from the left ventricle. Flecainide toxicity was suspected, leading to the discontinuation of flecainide treatment. The following day, the serum flecainide concentration was 1,348 ng/mL, exceeding the therapeutic window of 200-1,000 ng/mL. After discontinuing flecainide, the accelerated idioventricular rhythm ceased, and a regular sinus rhythm temporarily returned. We measured blood drug concentrations several times; our calculated half-life was 56.8 h, approximately five times longer than the half-life of 11.0 h stated on the package insert. To ensure safe and effective therapy with antiarrhythmic drugs, prioritizing therapeutic drug monitoring and carefully monitoring pharmacokinetics is important, particularly during the elimination phase.

An Explanation of Why Dose-Corrected Area Under the Curve for Alternate Administration Routes Can Be Greater than for Intravenous Dosing.

It is generally believed that bioavailability (F) calculated based on systemic concentration area under the curve (AUC) measurements cannot exceed 1.0, yet some published studies report this inconsistency. We teach and believe, based on differential equation derivations, that rate of absorption has no influence on measured systemic clearance following an oral dose, i.e., determined as available dose divided by AUC. Previously, it was thought that any difference in calculating F from urine data versus that from systemic concentration AUC data was due to the inability to accurately measure urine data. A PubMed literature search for drugs exhibiting F > 1.0 and studies for which F was measured using both AUC and urinary excretion dose-corrected analyses yielded data for 35 drugs. We show and explain, using Kirchhoff's Laws, that these universally held concepts concerning bioavailability may not be valid in all situations. Bioavailability, determined using systemic concentration measurements, for many drugs may be overestimated since AUC reflects not only systemic elimination but also absorption rate characteristics, which is most easily seen for renal clearance measures. Clearance of drug from the absorption site must be significantly greater than clearance following an iv bolus dose for F(AUC) to correctly correspond with F(urine). The primary purpose of this paper is to demonstrate that studies resulting in F > 1.0 and/or greater systemic vs urine bioavailability predictions may be accurate. Importantly, these explications have no significant impact on current regulatory guidance for bioequivalence testing, nor on the use of exposure (AUC) measures in making drug dosing decisions.

Association between psychomotor function and ALDH2 genotype after consuming barley shochu: A randomized crossover trial.

Sustained exposure to acetaldehyde, the major metabolite of ethanol, may influence psychomotor performance even after the breath ethanol level significantly drops several hours following ethanol consumption. We examined the relationship between psychomotor function and changes in exhaled ethanol and acetaldehyde concentrations after consuming a low dose (0.33 g/kg) of barley shochu, a traditional Japanese distilled alcohol beverage, at the point when the exhaled ethanol concentrations dropped below 78,000 parts per billion (0.15 mg/L), the standard threshold for driving under the influence of alcohol in Japan. We assessed how the genetic polymorphisms of rs671 G/G homozygous (*1/*1) and G/A heterozygous (*1/*2) of ALDH2 influenced the kinetics of ethanol and acetaldehyde in exhaled air and psychomotor dynamics using the Digit Symbol Substitution Test (DSST), Critical Flicker Fusion Test (CFFT), and visual analogue scale (VAS) up to 12 h after shochu or water intake. There was no significant difference in DSST and CFFT scores depending on genotype; however, the time required for the DSST to attain the level prior to drinking was longer in the ALDH2 *1/*2 group than in the *1/*1 group. In the VAS test, facial flushing and mood elevation tended to be higher in the *1/*2 group after shochu consumption. VAS scores for mood elevation and facial flushing correlated with acetaldehyde concentration in exhaled breath. These results indicate that DSST recovery tends to be slower and mood elevation higher in the ALDH2 *1/*2 group even when exposed to a low dose of alcohol.

Pharmacokinetics of lanoconazole in human skin after repeated topical application.

Drug disposition after topical application to the skin has not been fully elucidated, especially after repeated application. We conducted a clinical trial to evaluate the pharmacokinetics in the stratum corneum of healthy adults after repeated application of lanoconazole cream as a model drug. We applied 25 mg of 1% lanoconazole cream onto the pre-specified areas on the participants' back once daily for 5 days. The stratum corneum was sampled twice on each study day using a standardized tape-stripping method, and the amount of lanoconazole contained in the samples was quantified using the tandem mass spectrometry method. The obtained data were used to evaluate lanoconazole pharmacokinetics in the stratum corneum. The amount of lanoconazole in the stratum corneum after once daily repeated administration reached a steady state on day 3, and it was eliminated from the stratum corneum with a half-life of approximately 11 h after discontinuing application.

Possible Involvement of Muscarinic Receptor Blockade in Mirabegron Therapy for Patients with Overactive Bladder.

The selective ß 3-adrenoceptor agonist mirabegron, an established alternative to antimuscarinic therapy for patients with overactive bladder, induces additional effects against receptors, transporters, and hepatic enzymes. The present study aimed to elucidate the effects of mirabegron on muscarinic receptors in the rat bladder using radioligand binding and functional assays. Mirabegron (0.1-100 µM) inhibited specific [N-methyl-3H]scopolamine methyl chloride binding in the bladder and other tissues of rats in a concentration-dependent manner. Binding affinity in the bladder was similar to that in the heart and significantly higher than those in the submaxillary gland and brain. Mirabegron induced the concentration-dependent relaxation of carbachol-induced contractions in the rat isolated bladder. Further analyses using a two-site model revealed that the relative quantities of high- and low-affinity components for mirabegron were 44.5% and 55.5%, respectively. Respective pEC50 values were 7.06 and 4.97. Based on the receptor binding affinity and pharmacokinetics of mirabegron, muscarinic receptor occupancy in the human bladder for 24 hours after the administration of a single oral dose of 50 mg mirabegron was 37%-76%. The present results demonstrate for the first time that mirabegron may relax the detrusor smooth muscle not only by ß 3-adrenoceptor activation but also muscarinic receptor blockade. SIGNIFICANCE STATEMENT: Mirabegron, the first selective ß 3-adrenoceptor agonist, represents an alternative to antimuscarinic agents for management of overactive bladder (OAB). The present study aimed to clarify whether mirabegron directly binds to muscarinic receptors and affects cholinergic agonist-induced contractions in rat urinary bladder and to predict muscarinic receptor occupancy in human bladder after oral administration of mirabegron. The results demonstrated that mirabegron therapy for patients with OAB may be due not only to ß 3-adrenoceptor activation but also muscarinic receptor blockade.

Effects of Anticholinergic Drugs Used for the Therapy of Overactive Bladder on P-Glycoprotein Activity.

We evaluated the effects of anticholinergic drugs principally used for the therapy of overactive bladder (OAB) on the activity of P-glycoprotein, an efflux transport protein, in Caco-2 cells. The time-dependent changes in the fluorescence of residual rhodamine 123, a P-glycoprotein activity marker, in the apical region of Caco-2 cells were measured in the presence of anticholinergic drugs using time-lapse confocal laser scanning microscopy. The effect of anticholinergic drugs on human P-glycoprotein ATPase activity was also measured. The fluorescence of residual rhodamine 123 in untreated Caco-2 cells decreased over time. The gradual decrease in the fluorescence was significantly inhibited by treatment with cyclosporine A, darifenacin, and trospium. In contrast, oxybutynin, N-desethyl-oxybutynin (DEOB), propiverine, and its active metabolites (M-1, M-2), imidafenacin, solifenacin, or tolterodine had little effect on the efflux of rhodamine 123. P-Glycoprotein ATPase activity was increased by darifenacin. Darifenacin and trospium reduced the rhodamine 123 transfer across the apical cell membrane. These data suggest that darifenacin and trospium interact with P-glycoprotein. Additionally, darifenacin influenced P-glycoprotein ATPase activity. These results suggest that darifenacin may be a substrate of P-glycoprotein. This study is the first paper to test simultaneously the effects of 10 anticholinergic drugs used currently for the therapy of OAB, on the P-glycoprotein.

Effect of Royal Jelly on Mouse Isolated Ileum and Gastrointestinal Motility.

Royal jelly (RJ) is widely used as a cosmetic or dietary supplement to relieve various health disorders, such as dry skin, fatigue, and menopause. RJ has been recommended to improve constipation on a commercial basis. However, the detailed mechanisms by which RJ influences intestinal motility and whether RJ improves constipation remain unclear. Therefore, we investigated the effects of RJ on the motility of mouse ileum both in vitro and in vivo. Using myograph methods, RJ dose-dependently induced contractions of isolated ileal segments, which were inhibited by treatment with atropine. Eserine sulfate, a cholinesterase inhibitor, enhanced the RJ-induced contractions, whereas RJ treated with acetylcholinesterase did not result in ileum contraction. RJ-induced contractions were not affected by NG-nitro-l-arginine methyl ester, a nitric oxide synthase inhibitor, although nicotine-induced contractions were significantly enhanced. In contrast, in a gastrointestinal (GI) transit model, single oral administration of 300 mg/kg RJ did not affect GI transit in both normal mice and the loperamide-induced constipation model mice. These results demonstrate that acetylcholine in RJ directly acted on the muscarinic receptors of the mouse intestinal smooth muscle, causing it to contract in vitro. In contrast, single oral administration of RJ did not improve constipation. This study is the first to evaluate the effects of RJ on the motility of mouse ileum in in vitro and in vivo experiments for the validation of application of RJ as a gentle laxative.

No Effect of Digoxin on Rosuvastatin Pharmacokinetics in Healthy Subjects: Utility of Oita Combination for Clinical Drug-Drug Interaction Study.

This study evaluated the utility of combination of digoxin (0.25 mg) and rosuvastatin (5 mg) as a new transporter (P-glycoprotein/breast cancer resistance protein/organic anion-transporting polypeptide (OATP)1B1/OATP1B3) probe cocktail (Oita combination) for drug-drug interaction (DDI) studies by demonstrating lack of DDI of digoxin on the pharmacokinetics (PKs) of rosuvastatin, as it was already known that rosuvastatin did not affect digoxin PK. This was an open-label, two-period study in which the primary end points were the geometric mean ratio (GMR) of the area under the plasma rosuvastatin concentration-time curve from time zero to last (AUClast ) after rosuvastatin administration combined with digoxin to that after rosuvastatin administration alone and its 90% confidence interval (CI). As the GMR of AUClast was 0.974 and its 90% CI was 0.911-1.042, it was judged that digoxin does not affect rosuvastatin PK. Results of this study have rationalized utility of the Oita combination as a transporter probe cocktail for clinical DDI studies.

Histological evaluation of nintedanib in non-alcoholic steatohepatitis mice.

AIMS: In addition to potentially progressing to either cirrhosis or hepatocellular carcinoma, non-alcoholic steatohepatitis (NASH) is currently the leading indication for liver transplantation. Nintedanib has been clinically used to treat idiopathic pulmonary fibrosis for many years, but its effects in an animal model of NASH have not been tested. The purpose of this study was to evaluate the effects of nintendanib on NASH in choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD)-fed mice. MAIN METHODS: Male C57BL/6 mice were fed a CDAHFD for 6 weeks to induce NASH with liver fibrosis, and they were administered nintedanib (60 mg/kg/day) or distilled water orally in the last 2 weeks of the feeding period. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), triglyceride, and non-esterified fatty acids concentrations were measured. Serum cytokeratin 18 fragment (CK18) was detected using ELISA. Liver tissue sections from mice were stained with hematoxylin-eosin and Masson's trichrome to assess the level of steatohepatitis and fibrosis. KEY FINDINGS: CDAHFD-fed mice exhibited higher serum ALT, AST, and ALP levels compared with Control mice. A significant increase in the serum CK18 level was observed in the NASH group compared with the Control group. CDAHFD feeding also enhanced steatohepatitis and hepatic fibrosis pathological features, which were reduced after nintedanib treatment. SIGNIFICANCE: Nintedanib exerted anti-inflammatory and anti-fibrotic effects in CDAHFD-induced NASH mice.

Effects of ICI204,448, naloxone methiodide and levocetirizine on the scratching behavior induced by a κ-opioid antagonist, nor-BNI, in ICR mice.

OBJECTIVE: In this study, we aimed to study the effects of ICI204,448, naloxone methiodide and levocetirizine on the scratching behavior induced by intradermal injection of a ?-opioid antagonist, nor-binaltorphimine (nor-BNI), into the rostral back of ICR mice were investigated. MATERIALS AND METHODS: Male ICR mice weighing 30?35 g were used. The number of scratching episodes were counted for 60 min after i.d. injection of nor-BNI. RESULTS: nor-BNI dose dependently increased in the number of scratching episodes in ICR mice. nor-BNI-induced scratching behavior was inhibited by not only nalfurafine but also ICI204,448, a peripherally selective ?-opioid agonist. Naloxone and naloxone methiodide, a peripherally restricted ?-opioid antagonist, also inhibited nor-BNI-induced scratching behavior. Scratching behavior induced by nor-BNI was inhibited by chlorpheniramine as well as levocetirizine, a third-generation H1 antagonist that does not cross into the CNS. CONCLUSION: These results suggest that scratching behavior induced by this ?-opioid antagonist, nor-BNI, is related to not only central but also peripheral opioid and H1 receptors.

Age-related changes to vascular protease-activated receptor 2 in metabolic syndrome: a relationship between oxidative stress, receptor expression, and endothelium-dependent vasodilation.

Protease-activated receptor 2 (PAR2) is expressed in vascular endothelium. Nitric oxide (NO) - cyclic GMP-mediated vasodilation in response to 2-furoyl-LIGRLO-amide (2fLIGRLO), a PAR2-activating peptide, is impaired in aortas from aged SHRSP.Z-Leprfa/IzmDmcr (SHRSP.ZF) rats with metabolic syndrome. Here we investigated mechanisms linking PAR2's vascular effects to phenotypic characteristics of male SHRSP.ZF rats at 10, 20, and 30 weeks of age. We found vasodilation responses to either 2fLIGRLO or enzyme-mediated PAR2 activation by trypsin were sustained until 20 weeks and lessened at 30 weeks. PAR2 protein and mRNA levels were lower in aortas at 30 weeks than at 10 and 20 weeks. PAR2-mediated responses positively correlated with PAR2 protein and mRNA levels. Decreased cGMP accumulation in the presence of 2fLIGRLO paralleled the decreased relaxations elicited by nitroprusside and the cGMP analog 8-pCPT-cGMP, and the less soluble guanylyl cyclase protein at 30 weeks. 2fLIGRLO-induced relaxation was negatively correlated with serum thiobarbituric acid reactive substances, an index of oxidative stress, which increased with age. Forward stepwise data regression supported a model of age-related decreases in PAR2 function resulting from decreased PAR2 mRNA and increased oxidative stress. We conclude that decreased responsiveness of aortic smooth muscle to NO and downregulation of receptor expression impair PAR2 functions at later stages of metabolic syndrome in SHRSP.ZF rats.

Characterization of muscarinic receptor binding by the novel radioligand, [(3)H]imidafenacin, in the bladder and other tissues of rats.

The present study aimed to directly characterize specific binding sites of tritium ([(3)H])-labeled imidafenacin, a new radioligand for labeling muscarinic receptors, in the bladder and other peripheral or central nervous tissues of rats. Muscarinic receptors in rat tissues were measured by radioligand binding assay using [(3)H]imidafenacin. Specific [(3)H]imidafenacin binding in rat tissues was saturable, reversible, and of high affinity. Estimated dissociation constants (Kd values) were significantly lower in submaxillary gland and prostate and higher in heart than in bladder, indicating lower Kd values in M1 and M3 subtype- than M2 subtype-dominating tissues. Unlabeled imidafenacin and clinically used antimuscarinic agents competed with [(3)H]imidafenacin for binding sites in bladder and other tissues in a concentration-dependent manner, which indicated pharmacological specificity of [(3)H]imidafenacin binding sites. Pretreatment with N-(2-chloroethyl)-4-piperidinyl diphenylacetate (4-DAMP mustard), an irreversible inactivating agent of M3 subtype, significantly decreased the number of [(3)H]imidafenacin binding sites in bladder, submaxillary gland, and colon, but not in heart. [(3)H]imidafenacin labeled muscarinic receptors in M1 and M3 subtype-dominating tissues with higher affinity than [N-methyl-(3)H]scopolamine methyl chloride (NMS). [(3)H]imidafenacin is a useful radioligand to label muscarinic receptors in M1- and M3-dominating tissues with high affinity.

Functional Relationship between Arterial Tissue and Perivascular Adipose Tissue in Metabolic Syndrome.

Metabolic syndrome is a complex of disorders that includes visceral obesity, insulin resistance, hypertension, and dyslipidemia. It is characterized by an increased risk for serious cardiovascular events. Adipocytes are now recognized to contribute to the development of cardiovascular complications in metabolic syndrome via the release of several bioactive substances (adipocytokines). Obesity induces an increase in the volume of perivascular adipose tissue (PVAT), which is located outside the blood vessels. In recent years, PVAT has been reported to produce/release vasoactive adipocytokines. Thus, PVAT can modulate vasomotor function by releasing vasorelaxing/vasocontracting factors, resulting in the development of cardiovascular disease due to metabolic syndrome. By using animal models (SHR/NDmcr-cp rats, SHRSP.Z-Lepr(fa)/IzmDmcr rats, and B6.BKS (D)-Lepr(fa)/J mice), we have demonstrated that chronic oxidative-nitrative stress is closely linked to the development of vascular dysfunction in response to nitric oxide (NO) in resistant arteries with increasing age/exposure to metabolic abnormalities. Further, our recent findings have led us to believe that PVAT helps in the regulation of vasodilation to compensate for the impaired vasodilation observed in pathophysiological conditions in the mesenteric arteries of SHRSP.Z-Lepr(fa)/IzmDmcr rats. However, a breakdown of the compensatory system occurs with long-term exposure to metabolic abnormalities. We propose the concept of the functional regulation of vascular tissue by PVAT in metabolic syndrome.

Panax notoginseng saponins ameliorate impaired arterial vasodilation in SHRSP.Z-Lepr(fa) /lzmDmcr rats with metabolic syndrome.

Panax notoginseng saponins (PNS) are major components of Panax notoginseng, a herb with established clinical efficacy against vascular diseases. SHRSP.Z-Lepr(fa) /IzmDmcr (SHRSP.ZF) rats, a new animal model for metabolic syndrome, display an impaired vasorelaxation response in aortas and mesenteric arteries that is mediated by nitric oxide (NO). This study investigated whether PNS and its components can ameliorate this vascular dysfunction in SHRSP.ZF rats. In an in vitro study, in the presence or absence of PNS and its components, vasodilation in response to nitroprusside was determined from myographs under isometric tension conditions in aortas and mesenteric arteries from male SHRSP.ZF rats at 18-20 weeks of age. In an in vivo study, PNS (30 mg/kg per day) was orally administered to SHRSP.ZF rats from 8 to 20 weeks of age. In vitro treatment with PNS and Ginsenoside Rb1 increased nitroprusside-induced relaxation of aortas and mesenteric arteries in SHRSP.ZF rats. The PNS-induced increase was not affected by a nitric oxide (NO) synthase inhibitor or endothelium denudation. Relaxation in response to a cell-permeable cGMP analogue was increased by PNS, but cGMP accumulation by nitroprusside was not altered. In vivo treatment with PNS in SHRSP.ZF rats lowered blood pressure and increased relaxation and the expression of soluble guanylyl cyclase protein in arteries, without affecting metabolic abnormalities. These results indicate that PNS causes an increase in vasodilation in response to NO and a decrease in blood pressure, resulting in protection against vascular dysfunction in SHRSP.ZF rats. PNS might be beneficial in alleviating impaired vasodilation in metabolic syndrome.

A maternal high salt diet disturbs cardiac and vascular function of offspring.

AIMS: High salt intake is an environmental factor that promotes increased blood pressure. We previously demonstrated that high salt diet causes aggravation of hypertension and impaired vasodilation in response to nitric oxide (NO) in young spontaneously hypertensive rats (SHR), which exhibit low sensitivity to salt in adulthood. Changes in offspring blood pressure and cardiovascular structures have been reported. However, it remains unclear to what extent a maternal high salt intake may affect cardiac and/or vascular function in offspring. Therefore, we investigated influence of exposure to a maternal high salt diet during gestation and lactation on offspring's cardiac and arterial functions in SHR. MAIN METHODS: SHR dams were fed either a high salt diet or a control diet. After weaning, the offspring were fed the high salt diet or control diet for 8weeks. KEY FINDINGS: Compared with offspring of control diet-fed dams, at 12weeks of age, offspring of the high-salt diet-fed dams had lower blood pressure, heart rate, indices of both left ventricular systolic and diastolic function, and a decreased aortic vasodilation response to NO. Postnatal high salt intake did not affect blood pressure, vasodilatory response, or cardiac function in offspring of high-salt diet-fed dams. Neither maternal nor postnatal dietary salt altered levels of lipid peroxide, superoxide dismutase, or angiotensinogen mRNA in serum and ventricle of the offspring. SIGNIFICANCE: Exposure to high maternal dietary salt induces cardiac and vascular dysfunction in offspring. These results point to the possible importance of avoiding excess dietary salt during gestation and lactation.

Enhanced Nitric Oxide Synthase Activation via Protease-Activated Receptor 2 Is Involved in the Preserved Vasodilation in Aortas from Metabolic Syndrome Rats.

Endothelium-dependent vasodilation via protease-activated receptor 2 (PAR2) is preserved in mesenteric arteries from SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP.ZF) with metabolic syndrome even though nitric oxide (NO)-mediated vasodilation is attenuated. Therefore, we examined the PAR2 mechanisms underlying metabolic syndrome-resistant vasodilation in SHRSP.ZF aortas with ageing. In isolated aortas, the PAR2 agonist 2-furoyl-LIGRLO-amide (2fly) caused vasodilation that was sustained in male SHRSP.ZF until 18 weeks of age, but was attenuated afterwards compared with age-matched Wistar-Kyoto rats (controls) at 23 weeks. In contrast, acetylcholine-induced vasodilation was impaired in SHRSP.ZF already at 18 weeks of age. Treatments of aortas with inhibitors of NO synthase and soluble guanylate cyclase abolished the sustained 2fly- and residual acetylcholine-induced vasodilation in SHRSP.ZF at 18 weeks of age. In the aortas of SHRSP.ZF, 8-bromo-cGMP-induced vasodilation, NO production and cGMP accumulation elicited by 2fly were not different from in the controls. PAR2 agonist increased phospho-Ser1177-eNOS protein content only in SHRSP.ZF aortas. These results indicate that vasodilation mediated by PAR2 is sustained even though NO-dependent relaxation is attenuated with ageing/exposure to metabolic disorders in large-caliber arteries from SHRSP.ZF. PAR2 stimulation of NO production via an additional pathway that targets phosphorylation of Ser1177-eNOS suggests a regulatory mechanism for sustaining agonist-mediated vasodilation in metabolic syndrome.

Is hyperuricemia a risk factor for arteriosclerosis? Uric acid and arteriosclerosis in apolipoprotein e-deficient mice.

Although hyperlipidemia, high blood pressure, and diabetes increase the risk of arteriosclerosis, it is not clear whether hyperuricemia increases the risk of arteriosclerosis or not. We examined the effects of uric acid and curative drugs for hyperuricemia on atherosclerosis-susceptible C57BL/6J apolipoprotein E-deficient (apoE(-/-)) mice. Male apoE(-/-) mice (age: 6 weeks) were fed a normal diet (normal diet group) or a uric acid-enriched diet. Mice fed the uric acid-enriched diet were divided into three groups and administered a drinking vehicle (high uric acid diet group), allopurinol (20 mg·kg(-1)·d(-1)), or benzbromarone (20 mg·kg(-1)·d(-1)) for 10 weeks. Serum uric acid concentrations were higher in the high uric acid diet group than in the normal diet group, and concentrations in the allopurinol and benzbromarone groups were lower than in the high uric acid diet group. Serum total cholesterol and triglyceride levels were lower in the allopurinol group than in the high uric acid diet group. Oxidative stress was lower in the benzbromarone group than in the high uric acid diet group. Atherosclerotic lesion areas were smaller in the allopurinol and benzbromarone groups than in the high uric acid diet group. Thus, hyperuricemia may not be an independent risk factor for arteriosclerosis; however, the administration of allopurinol and benzbromarone prevented the development of atherosclerosis in apoE(-/-) mice fed a uric acid-enriched diet. The anti-atherosclerotic effect was in part due to lower total cholesterol and oxidative stress in the serum. Other possible mechanisms underlying this effect should be investigated.