Associations of ADH1B and ALDH2 genotypes and alcohol flushing with drinking history, withdrawal symptoms, and ICD-10 criteria in Japanese alcohol-dependent men

OBJECTIVES

Given the high prevalence of fast-metabolizing alcohol dehydrogenase-1B*2 (ADH1B*2) and inactive aldehyde dehydrogenase-2*2 (ALDH2*2) alleles in East Asians, we evaluated how the ADH1B/ALDH2 genotypes and alcohol flushing might affect the development of alcohol dependence (AD).

METHODS

We evaluated how the ADH1B/ALDH2 genotypes and self-reported alcohol flushing affected history of drinking events and withdrawal symptoms and ICD-10 criteria in 4116 Japanese AD men.

RESULTS

The ADH1B*1/*1 group and ALDH2*1/*1 group were 1-5 years younger than the ADH1B*2(+) and ALDH2*1/*2 groups, respectively, for all of the ages at onset of habitual drinking, blackouts, daytime drinking, uncontrolled drinking, withdrawal symptoms, and first treatment for AD, and the current age. Blackouts were more common in the ADH1B*1/*1 group and ALDH2*1/*1 group. Daytime drinking, uncontrolled drinking, and withdrawal symptoms, such as hand tremor, sweating, convulsions, and delirium tremens/hallucinations were more common in the ADH1B*1/*1 group. The ADH1B*1/*1 was positively associated with the ICD-10 criteria for 'tolerance' and 'withdrawal symptoms'. The ADH1B*1/*1 group and ALDH2*1/*2 group had a larger ICD-10 score. Never flushing was reported by 91.7% and 35.2% of the ALDH2*1/*1 and ALDH2*1/*2 carriers, respectively. After a 1-2-year delay in the onset of habitual drinking in the former-/current-flushing group, no differences in the ages of the aforementioned drinking milestones were found according to the flushing status.

CONCLUSION

The ADH1B*1/*1 and ALDH2*1/*1 accelerated the development of drinking events and withdrawal symptoms in Japanese AD patients. ICD-10 score was larger in the ADH1B*1/*1 group and ALDH2*1/*2 group. The effects of alcohol flushing on drinking events were limited.

Utility of Coproporphyrin-I Determination in First-in-Human Study for Early Evaluation of OATP1B Inhibitory Potential Based on Investigation of Ensitrelvir, an Oral SARS-CoV-2 3C-Like Protease Inhibitor

Coproporphyrin-I (CP-I) has been investigated as an endogenous biomarker of organic anion transporting polypeptide (OATP) 1B. Here, we determined the CP-I concentrations in a cocktail drug-drug interaction (DDI) study of ensitrelvir to evaluate the OATP1B inhibitory potential because ensitrelvir had increased plasma concentrations of rosuvastatin in this study, raising concerns about breast cancer resistance protein and OATP1B inhibition. Furthermore, CP-I concentrations were compared between active and placebo groups in a first-in-human (FIH) study of ensitrelvir to verify whether the OATP1B inhibitory potential could be estimated at an early drug development stage. In the cocktail DDI study, CP-I did not differ between with/without administration of ensitrelvir, indicating that ensitrelvir has no OATP1B inhibitory effect. Although there were some individual variabilities in CP-I concentrations among the treatment groups in the FIH study, the normalization of CP-I concentrations with pre-dose values minimized these variabilities, suggesting that this normalized method would be helpful for comparing the CP-I from different participants. Finally, we concluded that CP-I concentrations were not affected by ensitrelvir in the FIH study. These results suggested that the CP-I determination in an FIH study and its normalized method can be useful for an early evaluation of the OATP1B-mediated DDI potential in humans.

Evaluation of the Drug-Drug Interaction Potential of Ensitrelvir Fumaric Acid with Cytochrome P450 3A Substrates in Healthy Japanese Adults

BACKGROUND

Management of drug-drug interactions (DDIs) for ensitrelvir, a novel 3-chymotrypsin-like protease inhibitor of SARS-CoV-2 infection is crucial. A previous clinical DDI study of ensitrelvir with midazolam, a clinical index cytochrome P450 (CYP) 3A substrate, demonstrated that ensitrelvir given for 5 days orally with a loading/maintenance dose of 750/250 mg acted as a strong CYP3A inhibitor.

OBJECTIVES

The objectives of this study were to investigate the effect of ensitrelvir on the pharmacokinetics of CYP3A substrates, dexamethasone, prednisolone and midazolam, and to assess the pharmacokinetics, safety, and tolerability of ensitrelvir following multiple-dose administration of ensitrelvir.

METHODS

This was a Phase 1, multicenter, single-arm, open-label study in healthy Japanese adult participants. The effects of multiple doses of ensitrelvir in the fasted state on the pharmacokinetics of dexamethasone, prednisolone, and midazolam were investigated. Ensitrelvir was administered from Day 1 through Day 5, with a loading/maintenance dose of 750/250 mg for the dexamethasone and prednisolone cohorts whereas 375/125 mg for the midazolam cohort. Either dexamethasone, prednisolone, or midazolam was administered alone (Day - 2) or in combination with ensitrelvir (Day 5) in each of the cohorts. Additionally, dexamethasone or prednisolone was administered on Days 9 and 14. The pharmacokinetic parameters of ensitrelvir, dexamethasone, prednisolone, and midazolam were calculated based on their plasma concentration data with non-compartmental analysis. In safety assessments, the nature, frequency, and severity of treatment-emergent adverse events were evaluated and recorded.

RESULTS

The area under the concentration-time curve (AUC) ratio of dexamethasone on Day 5 was 3.47-fold compared with the corresponding values for dexamethasone alone on Day - 2 and the effect diminished over time after the last dose of ensitrelvir. No clinically meaningful effect was observed for prednisolone. The AUC ratio of midazolam was 6.77-fold with ensitrelvir 375/125 mg suggesting ensitrelvir at 375/125 mg strongly inhibits CYP3A similar to that at 750/250 mg. No new safety signals with ensitrelvir were reported during the study.

CONCLUSION

The inhibitory effect for CYP3A was confirmed after the last dose of ensitrelvir, and the effect diminished over time. In addition, ensitrelvir at 375/125 mg showed CYP3A inhibitory potential similar to that at 750/250 mg. These findings can be used as a clinical recommendation for prescribing ensitrelvir with regard to concomitant medications.

CLINICAL TRIAL REGISTRATION

Japan Registry of Clinical Trials identifier: jRCT2031210202.

Evaluation of drug-drug interactions of ensitrelvir, a SARS-CoV-2 3CL protease inhibitor, with transporter substrates based on in vitro and a clinical study

Drug-drug interaction (DDI) potentials of ensitrelvir, a novel oral inhibitor of 3C-like protease of SARS-CoV-2, for drug transporters were evaluated by in vitro and clinical studies. The target drug transporters assessed were P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), organic anion transporting polypeptide (OATP) 1B1, OATP1B3, organic anion transporter (OAT) 1, OAT3, organic cation transporter (OCT) 1, OCT2, multidrug and toxin extrusion (MATE) 1 and MATE-2K. In vitro study revealed that ensitrelvir is a substrate for P-gp and BCRP, and inhibits P-gp, BCRP, OATP1B1, OATP1B3, OCT1, and OAT3. Based on these results, a clinical DDI study to evaluate the effect of ensitrelvir on the pharmacokinetics of P-gp, BCRP, OATP1B1, OATP1B3, and OCT1 substrates was conducted with a cocktail approach using digoxin (P-gp substrate), rosuvastatin (BCRP, OATP1B1 and OATP1B3 substrate), and metformin (OCT1 substrate). The cocktail was administered first, and after the washout period, the cocktail was co-administered with 500 mg of ensitrelvir. No treatment-emergent adverse events were observed. Pharmacokinetic analyses demonstrated that the ratios (90% confidence intervals) of "cocktail with ensitrelvir" to "cocktail without ensitrelvir" for maximum plasma concentration and area under the plasma concentration-time curve were, respectively, 2.17 (1.72-2.73) and 1.31 (1.13-1.52) for digoxin, 1.97 (1.73-2.25) and 1.65 (1.47-1.84) for rosuvastatin, and 1.03 (0.91-1.16) and 1.02 (0.94-1.11) for metformin. The results indicate that the exposure levels of digoxin and rosuvastatin increased when co-administered with ensitrelvir, but those of metformin were not changed. In conclusion, ensitrelvir has impact on the exposure levels of P-gp, BCRP, OATP1B1 and OATP1B3 substrates. This article is protected by copyright. All rights reserved.

1131. Evaluation of drug-drug interaction potential of ensitrelvir for CYP3A by clinical studies and physiologically-based pharmacokinetic model

Background

Ensitrelvir is a new drug candidate to treat COVID-19 disease. According to the in vitro drug-drug interaction (DDI) study, time-dependent inhibition by ensitrelvir was observed on cytochrome P450 3A (CYP3A). The purpose of this study was to evaluate the effect of ensitrelvir on the pharmacokinetics (PK) of CYP3A substrates by clinial DDI studies and physiologically-based pharmacokinetic (PBPK) analyses.

Methods

Clinical studies: The effect of once daily multiple-doses of ensitrelvir with the loading dose on Day 1/ maintenance dose (750/250 mg) for 6 days on the PK of midazolam (MDZ) was assessed. MDZ was administered on Days -2 and 6. The effects of once daily multiple-doses of ensitrelvir with 750/250 mg for 5 days on the PK of dexamethasone (DXS) and prednisolone (PLS) were also assessed because these corticosteroids were also CYP3A substrates. DXS and PLS were administered on Days -2, 5 (co-administration with ensitrelvir), 9 and 14 to evaluate the effects after the last dose of ensitrelvir.

PBPK analyses: The effects of once daily multiple-doses of ensitrelvir with another dose regimen (the loading dose/mentenance dose [375/125 mg] for 5 days) on the PK of CYP3A substrates were predicted using Simcyp PBPK Simulator (Version 20, Certara UK Limited, UK).

Results

The AUC0-inf of MDZ co-administered with ensitrelvir was increased by 8.80-fold compared to those of MDZ alone, indicating that ensitrelvir is a strong CYP3A inhibitor with 750/250 mg for 6 days. The AUC0-inf of DXS on Day 5 was increased 3.47-fold and the effect of ensitrelvir on the PK of DXS was diminished over time after the last dose of ensitrelvir. The AUC0-inf of PLS on Day 5 was increased 1.25-fold and no clinically meaningful effect of ensitrelvir on the PK of PLS was observed. The PBPK analyses predicted that the co-administration of ensitrelvir increased the AUC of MDZ by 3.83-fold and the AUC of DXS by 2.49-fold following ensitrelvir at 375/125 mg for 5 days. A clinical study with MDZ under the analyses conditions is underway to confirm the PBPK results.

Conclusion

The clinical study revealed that ensitrelvir affects the PK of CYP3A substrates with 750/250 mg for 5 or 6 days. The PBPK analyses suggests that ensitrelvir is expected to a moderate inhibitor of CYP3A with 375/125 mg for 5 days.

Disclosures

Ryosuke Shimizu, Shionogi & Co., Ltd.: employee Kana Horiuchi, Shionogi & Co., Ltd.: employee Hiroki Koshimichi, n/a, Shionogi & Co., Ltd.: employee Takanobu Matsuzaki, Ph.D., Shionogi & Co., Ltd.: Employee Shinpei Yoshida, Ph.D., Shionogi & Co., Ltd.: employee Shingo Sakamoto, n/a, Shionogi & Co., Ltd.: employee Ryuji Kubota, Ph.D., Shionogi & Co., Ltd.: employee|Shionogi & Co., Ltd.: employee.

1136. No Change of Pharmacokinetics of Metformin by Concomitant Use of Ensitrelvir

Background

Ensitrelvir is a novel oral SARS-CoV-2 3C-like protease inhibitor, and under late clinical development stage for COVID-19 diseases. Ensitrelvir exhibited an inhibition potency for organic cation transporter 1 (OCT1) and multidrug and toxin extrusion protein 1 (MATE1) in in vitro study and clinical drug-drug interaction (DDI) study is required judging from DDI guidance. Metformin is widely used for treatment of diabetes, and is a sensitive substrate for OCT1 and MATE1. We evaluated the effect of ensitrelvir on the pharmacokinetics (PK) of metformin with physiologically-based pharmacokinetic (PBPK) modeling and simulation and clinical DDI study.

Methods

The PBPK model of ensitrelvir was developed based on the physicochemical parameters, in vitro transporter inhibition parameters, and estimated PK parameters for human. DDI simulations between ensitrelvir and metformin were performed. Simcyp PBPK Simulator (Version 20, Certara UK Limited, UK) was used to develop PBPK model and simulate the DDIs. The in vitro 50% inhibitory concentration (IC50) values of each transporter were used as inhibition constant (Ki) for DDI simulations. Based on the PBPK analysis, the clinical DDI study planed.

Results

PBPK analysis: As the result of DDI simulation, ensitrelvir increased the area under the curve (AUC) of metformin by 12%. The result suggests that in vivo DDI potency of ensitrelvir via inhibition of OCT1 or MATE1 would be low at a single dose of ensitrelvir 1000 mg.

Clinical DDI study: The plasma concentration-time profile of metformin and ensitrelvir were monitored after 96 hours from a single dose of metformin with or without ensitrelvir. Ensitrelvir does not have effect on the PK of metformin (a geometric mean of AUC ratio was 1.02, Japanese healthy subjects, N=14), suggesting no MATE1 and OCT1 inhibition by ensitrelvir at a clinical dose. The PBPK analysis could well predict the clinical DDI study result.

Conclusion

The results of PBPK analysis and the clinical DDI study suggest that no OCT1 and MATE1 inhibition by ensitrelvir is in the clinical dose. Therefore, ensitrelvir does not have a clinically meaningful effect on the pharmacokinetic profile of OCT1 and/or MATE1 substrates including metformin.

Disclosures

Kana Horiuchi, Shionogi & Co., Ltd.: employee Hiroki Koshimichi, n/a, Shionogi & Co., Ltd.: employee Takanobu Matsuzaki, Ph.D., Shionogi & Co., Ltd.: Employee Ryosuke Shimizu, Shionogi & Co., Ltd.: employee Shinpei Yoshida, Ph.D., Shionogi & Co., Ltd.: employee Ryuji Kubota, Ph.D., Shionogi & Co., Ltd.: employee|Shionogi & Co., Ltd.: employee Shingo Sakamoto, n/a, Shionogi & Co., Ltd.: employee.

Validation of the Ten-Item Internet Gaming Disorder Test (IGDT-10) based on the clinical diagnosis of IGD in Japan

BACKGROUND AND AIMS

Although the Ten-Item Internet Gaming Disorder Test (IGDT-10) has been translated into Japanese and widely used, the Japanese version has not previously been validated. We used the clinical diagnosis of IGD as a gold standard for validating the test.

METHODS

The Japanese version was validated using 244 gamers drawn from the general young population in Japan. Expert interviews using the Japanese version of the Structured Clinical Interview for Internet Gaming Disorder evaluated diagnoses of Internet gaming disorder (IGD). This resulted in a diagnosis of IGD for eight individuals, categorized as the gold standard group. The screening performance of the two Japanese versions with different scoring conditions was examined: the scoring method proposed by the original study (original version) and a less stringent scoring method where responses of either "often" or "sometimes" were regarded as affirmative (modified version).

RESULTS

The results of the sensitivity and specificity analyses, the Cronbach's alpha and the receiver operating characteristics analysis revealed a higher screening performance for the modified versus the original version. The optimum cutoff for the modified version was 5 or more - the sensitivity, specificity, and Youden's index were 87.5, 85.2, and 72.7%, respectively. The rate of probable IGD using the original and modified versions were 1.8% and 11.3%, respectively.

DISCUSSION AND CONCLUSION

A less stringent scoring method for the Japanese version of IGDT-10 showed a higher screening performance than the original scoring method. Future studies comprising different ethnic groups and gaming cultures should further examine the suggested scoring method.

Increasing important roles of child and adolescent psychiatrists in the treatment of gaming disorder: Current status in Japan

BACKGROUND

Digital gaming is the most common leisure activity among children and adolescents in Japan, especially in males. Playing online gaming has become more common among school-age children over the years. As a result, excessive online gaming in younger children has become a significant social problem in Japan. Previous studies have demonstrated that excessive online gaming could cause various mental health issues in children and adolescents. At medical institutions having child and adolescent psychiatry services, there is an increasing number of children and adolescents with various problems related to excessive gaming. The aim of this study was to investigate the current practice of gaming disorder (GD) in clinical settings in Japan.

METHODS

The subjects of this study were all of 414 child and adolescent psychiatrists certified by the Japanese Society for Child and Adolescent Psychiatry (JSCAP). The study questionnaire was mailed to all subjects from the official secretariat of JSCAP. Study subjects were requested to answer the questionnaire anonymously. The survey contained three types of responses: open responses; single and multiple-choice responses; and, responses on a five-point Likert scale. The questionnaire consisted of 14 questions regarding GD.

RESULTS

We received 159 responses. The most common reason for a visit to child and adolescent psychiatry service which results in a subsequent diagnosis of GD was school refusal/absenteeism followed by disruption of sleep-awake rhythm. The most common specialized treatment for GD currently offered at child and adolescent psychiatry service is individual psychotherapy. The two most frequently experienced difficulties in the treatment of GD were low motivation to achieve recovery and a large variety of combined problems other than excessive gaming itself. With regard to the three most common psychiatric comorbidities of GD, they were autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and depression.

DISCUSSION

The results of our survey revealed that although GD is a behavioral addiction, many children and adolescents with GD first visit child and adolescent psychiatry clinics rather than specialized clinics for addiction which are usually designed and staffed for adult patients. Because it is known that GD is more prevalent among young males, including junior high and high school students, GD has become one of the most important clinical issues in child and adolescent psychiatry today. The important roles of child and adolescent psychiatrists in the treatment of GD has been increasing.

Species difference in brain penetration of P-gp and BCRP substrates among monkey, dog and mouse

The brain penetration of 19 drugs, including P-glycoprotein (P-gp) and/or breast cancer resistance protein (BCRP) substrates, was compared among mice, cynomolgus monkeys and beagle dogs. The brain-to-plasma concentration ratios (K_p,brain) of the tested compounds in monkey and dog showed good correlation, whereas species differences were observed between non-rodents (monkey/dog) and rodents (mouse). In particular, the K_p,brain values of 7 compounds out of 12 P-gp substrates (K_p,brain ratio in P-gp knockout mice versus wild-type mice ≥3) in monkey and dog were more than three-fold higher than those in mice and a similar trend was observed in the brain-to-plasma unbound concentration ratios (K_p,uu,brain). The cerebral spinal fluid (CSF) drug concentrations (C_CSF), a surrogate for unbound brain concentration (C_u,brain), were also compared between dog and monkey, and the CSF-to-plasma unbound concentration ratios (K_p,uu,CSF) of BCRP substrates in dog were notably higher than those in monkey, although non-bcrp substrates showed good correlation. Also, the K_p,uu,CSF values of BCRP substrates in dog were clearly higher than the K_p,uu,brain values, indicating that the dog C_CSF of BCRP substrates was not suitable as a surrogate of C_u,brain. These observations should be useful when selecting the appropriate animal models for CNS drug discovery.

Development and validation of a nine-item short screening test for ICD-11 gaming disorder (GAMES test) and estimation of the prevalence in the general young population

BACKGROUND AND AIMS

A definition of gaming disorder (GD) was introduced in ICD-11. The purpose of this study was to develop a short screening test for GD, utilizing a reference GD group. It also sought to estimate the prevalence of GD among individuals, representative of the general young population in Japan.

METHODS

Two hundred eighty one men and women selected from the general population, aged between 10 and 29 years, and 44 treatment seekers at our center completed a self-reported questionnaire comprising candidate questions for the screening test. The reference group with ICD-11 GD was established, based on face-to-face interviews with behavioral addiction experts, using a diagnostic interview instrument. The questions in the screening test were selected to best differentiate those who had GD from those who did not, and the cutoff value was determined using the Youden index.

RESULTS

A nine-item screening test (GAMES test) was developed. The sensitivity and specificity of the test were both 98% and the positive predictive value in the study sample was 91%. The GAMES test comprised two factors, showed high internal consistency and was highly reproducible. The estimated prevalence of GD among the general young population was 7.6% (95% confidence interval; 6.6-8.7%) for males and 2.5% (1.9-3.2%) for females, with a combined prevalence of 5.1% (4.5-5.8%).

DISCUSSION AND CONCLUSION

The GAMES test shows high validity and reliability for screening of ICD-11 GD. The estimated prevalence of 5.1% among the general young population was comparable to the pooled estimates of young people globally.

Change of Internet Use and Bedtime among Junior High School Students after Long-Term School Closure Due to the Coronavirus Disease 2019 Pandemic

Most schools in Japan were closed in spring 2020 due to the novel coronavirus disease 2019 (COVID-19) pandemic. We investigated lifestyle and internet use among junior high school students across eight schools after long-term school closure and compared the data with those we obtained from previous surveys. In the summers of 2018, 2019, and 2020, we conducted questionnaire surveys on seventh-grade students from the same schools. In total, 2270 participants were analyzed. All questionnaires included items regarding background, bedtime, and internet use. The participants of the 2020 survey had significantly less sleepiness during classes and longer internet use times compared with those of the previous surveys. In the 2020 survey, the rate of problematic internet use (Young’s Diagnostic Questionnaire score, ≥5) was not significantly different from the results of previous surveys. The COVID-19 pandemic might have strongly influenced the sleepiness experienced by students in classes and increased the time spent using the internet since the summer of 2020. Our results indicate the need for attempts to encourage students to improve their sleep habits and moderate their media use.

Unguided Chatbot-Delivered Cognitive Behavioural Intervention for Problem Gamblers Through Messaging App: A Randomised Controlled Trial

Internet-delivered intervention may be an acceptable alternative for the more than 90% of problem gamblers who are reluctant to seek face-to-face support. Thus, we aimed to (1) develop a low-dropout unguided intervention named GAMBOT integrated with a messaging app; and (2) investigate its effect. The present study was a randomised, quadruple-blind, controlled trial. We set pre-to-post change in the Problem Gambling Severity Index (PGSI) as the primary outcome and pre-to-post change in the Gambling Symptom Assessment Scale (G-SAS) as a secondary outcome. Daily monitoring, personalised feedback, and private messages based on cognitive behavioural theory were offered to participants in the intervention group through a messaging app for 28 days (GAMBOT). Participants in the control group received biweekly messages only for assessments for 28 days (assessments only). A total of 197 problem gamblers were included in the primary analysis. We failed to demonstrate a significant between-group difference in the primary outcome (PGSI - 1.14, 95% CI - 2.75 to 0.47, p = 0.162) but in the secondary outcome (G-SAS - 3.14, 95% CI - 0.24 to - 6.04, p = 0.03). Only 6.7% of the participants dropped out during follow-up and 77% of the GAMBOT group participants (74/96) continued to participate in the intervention throughout the 28-day period. Integrating intervention into a chatbot feature on a frequently used messaging app shows promise in helping to overcome the high dropout rate of unguided internet-delivered interventions. More effective and sophisticated contents delivered by a chatbot should be sought to engage over 90% of problem gamblers who are reluctant to seek face-to-face support.

Application of the eleventh revision of the International Classification of Diseases gaming disorder criteria to treatment-seeking patients: Comparison with the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders Internet gaming disorder criteria

The World Health Organization included gaming disorder (GD) in the eleventh revision of International Classification of Diseases in 2019. Due to the lack of diagnostic tools for GD, a definition has not been adequately applied. Therefore, this study aimed to apply an operationalized definition of GD to treatment-seekers. The relationship between the diagnoses of GD and Internet gaming disorder (IGD) in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders was also examined. Methods: Study participants comprised 241 treatment-seekers who had engaged in excessive gaming and experienced related problems. Psychiatrists applied the GD diagnostic criteria to the participants using a diagnostic form developed for this study. Information on gaming behavior and functional impairment was obtained through face-to-face interviews conducted by clinical psychologists. Results: In total, 78.4 and 83.0% of the participants fulfilled the GD and IGD diagnostic criteria, respectively. The sensitivity and specificity of GD diagnosis were both high when the IGD diagnosis was used as the gold standard. Participants with GD preferred online PC and console games, spent significantly more time gaming, and showed a higher level of functional impairment compared to those who did not fulfill the GD diagnostic criteria. Discussion and Conclusion: The definition of GD can be successfully applied to treatment-seekers with excessive gaming and related problems. A high concordance of GD and IGD diagnoses was found in those participants with relatively severe symptoms. The development and validation of a diagnostic tool for GD should be explored in future studies.

Relationship between problematic gaming and age at the onset of habitual gaming

BACKGROUND

Some studies have revealed that a substantial proportion of the younger population has engaged in problematic gaming with even infants recently being able to enjoy video games. However, the relationship between the risk for problematic gaming and age at which habitual gaming starts remains unknown. This study therefore investigated this relationship among adolescents.

METHODS

A survey was conducted at eight public junior high schools across Japan. The questionnaire included items regarding the background, night-time sleep, age at which weekly gaming began, time spent on the Internet and gaming, the Japanese version of Young's Diagnostic Questionnaire, the Ten-Item Internet Gaming Disorder Test (IGDT-10), and others. We analyzed 549 participants who engaged in weekly gaming and have played games during the past year.

RESULTS

Among the participants, 1.8% were suspected to have Internet gaming disorder (IGDT-10 ≥ 5). Bedtime and wake-up time on weekdays and holidays were significantly later among problematic gamers (IGDT-10 ≥ 3) than among normal gamers (IGDT-10 ≤ 2). Onset of weekly gaming before the age of 5 was associated with a significantly higher risk of problematic gaming than onset of weekly gaming after the age of 10.

CONCLUSIONS

Our results revealed that the risk for problematic gaming was positively associated with a younger age at which weekly gaming begins. Longitudinal problematic gaming prevention, starting from an early stage, is thus necessary.

The antagonistic activity profile of naloxone in μ-opioid receptor agonist-induced psychological dependence

Naloxone is a μ-opioid receptor antagonist that has been used to prevent overdose-related respiratory depression and deaths by the illicit use of opioids. Naloxone can also deter the abuse potential of opioids, but little has been reported regarding its antagonistic activity profile against opioid-induced psychological dependence. This study aimed to confirm the antagonistic activity profile of naloxone against several μ-opioid receptor agonists and investigate whether naloxone could affect the psychological dependence induced by widely used μ-opioid receptor agonist, oxycodone. In the Guanosine-5'-o-(3-thio) triphosphate (GTPγS) binding assay, naloxone (30-30,000 nM) inhibited the GTPγS binding induced by oxycodone, hydrocodone, morphine, and fentanyl. It elicited parallel rightward shifts in the concentration-response curves, indicating that naloxone possessed a competitive antagonistic activity profile against these μ-opioid receptor agonists. In the conditioned place preference test, oxycodone (0.01-1 mg/kg, i.v.) produced dose-dependent increases in place preference. The increased place preference induced by oxycodone (1 mg/kg) was significantly attenuated by co-administration of naloxone at a dose of 0.5 mg/kg but not 0.01 mg/kg. Naloxone (0.5 mg/kg, i.v.) also blocked oxycodone (1 mg/kg)-induced dopamine release in nucleus accumbens; however, at a lower dose (0.01 mg/kg), it did not affect the intrinsic dopamine release by oxycodone. These results indicate that the psychological dependence of oxycodone could be antagonized by naloxone, depending on the dose. This characterization might lead to a better understanding of the competitive antagonistic activity profile of naloxone for μ-opioid receptor in the brain.

The antiviral effects of baloxavir marboxil against influenza A virus infection in ferrets

Background

Baloxavir marboxil (BXM), the oral prodrug of baloxavir acid (BXA), greatly reduces virus titers as well as influenza symptoms of uncomplicated influenza in patients.

Objectives

To investigate the pharmacokinetic profiles of BXA and its efficacy against influenza A virus infection in ferrets.

Methods

Ferrets were dosed orally with BXM (10 and 30 mg/kg twice daily for 1 day), oseltamivir phosphate (OSP) (5 mg/kg twice daily for 2 days) or vehicle to measure the antiviral effects of BXM and OSP. The pharmacokinetic parameters of BXA was determined after single oral dosing of BXM.

Results

The maximum plasma concentrations of BXA were observed at 1.50 and 2.00 hours with the two BXM doses, which then declined with an elimination half‐life of 6.91 and 4.44 hours, respectively. BXM at both doses remained detectable in the plasma in ferrets, which may be due to higher stability in liver microsomes. BXM (10 and 30 mg/kg twice daily) treatment at Day 1 post‐infection (p.i.) reduced virus titers by ≥3 log10 of the 50% tissue culture infective doses by Day 2, which was significantly different compared with vehicle or OSP. Body temperature drops over time were significantly greater with BXM than with vehicle or OSP. Significant reduction in virus titers was also demonstrated when BXM was administrated after symptom onset at Day 2 p.i. compared with vehicle and OSP, although body temperature changes largely overlapped between Day 2 and Day 4.

Conclusions

The results highlight the rapid antiviral action of BXM with post‐exposure prophylaxis or therapeutic dosing in ferrets and offer support for further research on prevention of influenza virus infection and transmission.

Joint unloading inhibits articular cartilage degeneration in knee joints of a monosodium iodoacetate-induced rat model of osteoarthritis

OBJECTIVE

The aim of the study was to examine how mechanical unloading affects articular cartilage degeneration in the patellofemoral (PF) and tibiofemoral (TF) joints of a monosodium iodoacetate (MIA)-induced rat model of osteoarthritis (OA).

DESIGN

The study involved 60 male rats. OA was induced by intra-articular injecting MIA into both knee joints. All animals were equally divided into two groups: sedentary (SE) and hindlimb unloading (HU) groups. Histopathological changes in the articular cartilage of the PF and TF joints were evaluated using the Osteoarthritis Research Society International (OARSI) score and modified Mankin score at 2 and 4 weeks after MIA injection.

RESULTS

In the SE and HU groups, representative histopathological changes in OA were detected in the PF and TF joints. The OARSI and modified Mankin scores for the PF and TF joints tended to increase over time after the injection of 0.2 mg or 1.0 mg of MIA in the SE and HU groups. Both the scores for the HU group were significantly lower than those for the SE group [OARSI score: P < 0.0001 (1.0-mg injection at 4 weeks); modified Mankin score: P = 0.0116 (0.2-mg injection at 4 weeks); P = 0.0004 and < 0.0001 (1.0-mg injection at 2 and 4 weeks, respectively)].

CONCLUSION

This study revealed new histological evidence that indicates that unloading condition suppresses articular cartilage degeneration and is beneficial in many areas of basal and clinical research involving OA.

1350. Therapeutic Effects of Baloxavir Marboxil against Influenza A Virus Infection in Ferrets

Background

Baloxavir marboxil (BXM) is a novel small molecule inhibitor of cap-dependent endonuclease that is essential for influenza virus transcription and replication. In this study, pharmacokinetic profiles of BXM and baloxavir acid (BXA), an active form of BXM, were first examined in ferrets, and then the therapeutic effects of BXM against influenza A virus infection were compared with that of oseltamivir phosphate in ferrets.

Methods

The plasma exposure of BXA and BXM was examined after a single oral administration of BXM at doses of 10 and 30 mg/kg. The concentrations in plasma were determined by liquid chromatography-tandem mass spectrometry(LC/MS/MS). For efficacy study, ferrets infected intranasally with A/Kadoma/2006 (H1N1) were administrated 10 or 30 mg/kg of BXM orally twice daily for 1 day, starting at 1 day post-infection (p.i.) or administrated 10 mg/kg of BXM orally twice daily for 1 day, starting at 2 days p.i.. Oseltamivir phosphate was administered at doses of 5 mg/kg orally twice daily for 2 days as a comparison. The virus titer in the nasal washes and body temperature change were monitored during infection.

Results

BXA was detected in ferret plasma after a single oral administration of BXM at 10 and 30 mg/kg, in more than a dose-proportional manner. When the treatment was initiated at 1 day p.i., BXM at 10 and 30 mg/kg showed reduction of virus titer to an undetectable level on day 2 p.i. and statistically significant reduction in virus titer over time from day 2 to 3 p.i. compared with vehicle and oseltamivir phosphate. Moreover, the change of body temperature over time from 8 hours after the first administration to 3 days p.i. was significantly lower in BXM at 10 and 30 mg/kg than vehicle and oseltamivir phosphate. These effects were also observed in ferrets treated with BXM at 10 mg/kg even when administered at 2 day p.i. where ferret exhibit fever that is more than 1 degree higher than on 1 day p.i..

Conclusion

Single-day oral administration of BXM had beneficial effects on viral titer and symptoms in ferrets infected with influenza A virus, which were superior to those observed with oseltamivir phosphate and vehicle.

Disclosures

M. Kitano, Shionogi & Co., Ltd.: Employee, Salary. T. Matsuzaki, Shionogi & Co., Ltd.: Employee, Salary. R. Oka, Shionogi & Co., Ltd.: Employee, Salary. K. Baba, Shionogi TechnoAdvance Research & Co., Ltd.: Employee, Salary. T. Noda, Shionogi TechnoAdvance Research & Co., Ltd.: Employee, Salary. Y. Yoshida, Shionogi & Co., Ltd.: Employee, Salary. K. Sato, Shionogi & Co., Ltd.: Employee, Salary. R. Yoshida, Shionogi & Co., Ltd.: Employee, Salary. A. Sato, Shionogi & Co., Ltd.: Employee, Salary. H. Kamimori, Shionogi & Co., Ltd.: Employee, Salary.

T. Shishido, Shionogi & Co., Ltd.: Employee, Salary. A. Naito, Shionogi & Co., Ltd.: Employee, Salary.

High-pressure liquid chromatography of free nucleotide patterns in normal and abnormal keratinocytes

A method for analyzing free nucleotides in the epidermis of the guinea pig is presented. Free nucleotides were extracted by using a methylalethanol mixture, and the analysis was carried out by high-pressure liquid chromatography on a column of Lichrosorb-NH2 with a single buffer of potassium phosphate. The concentration of total free nucleotides in the epidermis is about 4 times greater than that in the liver, kidney, spleen, or intestinal epithelium.l The free nucleotide level is markedly elevated in the hyperkeratotic epidermis induced by n-hexadecane. The alternation of free nucleotides in hyperkeratotic epidermis is discussed in relation to nucleic acid content, DNase, disc-electrophoretic properties of DNase, and salvage pathway enzymatic activity. Significant increases in the enzyme activity of the salvage pathway and in neutral DNase were observed in the hyperkeratotic stage. However, the DNA content and acid DNase activity were decreased. It is suggested that the pool size of free nucleotides in the epidermis is affected by the salvage enzyme system.

A radiographic analysis of alignment of the lower extremities--initiation and progression of varus-type knee osteoarthritis

OBJECTIVE

This study aimed to investigate alignment based on age in normal knees and alignment based on deformity in osteoarthritis (OA) knees using detailed radiographic parameters.

DESIGN

Various parameters were measured from weight-bearing long leg radiographs of 1251 legs (797 normal and 454 OA knees) as a cross-sectional study. Normal knees were classified by age (young, middle aged, aged, and elderly) and symptomatic OA knees on the basis of the alignment (femorotibial angle (FTA): mild, moderate, severe and profound). The mean measurements in each group were calculated and compared within each group.

RESULTS

The femoral shaft showed medially bowed curvature (femoral bowing) of approximately 2° in the young normal group, which shifted to lateral bowing with age. However, OA knees showed larger lateral bowing with OA grade, which might reduce the condylar-shaft angle and subsequently shifted the mechanical axis medially. Progression of mild to moderate OA might be associated with a decreasing condylar-shaft angle (femoral condylar orientation) and widening condylar-plateau angle (joint space narrowing) rather than decreasing tibial plateau flattering. Steeping of the tibial plateau inclination due to increasing tibial plateau shift (tibial plateau compression) rather than medial tibial bowing might be the main contributor to worsening of varus deformity in knees with severe and profound OA.

CONCLUSIONS

This cross-sectional study might provide the possibility of OA initiation and progression. The lateral curvature of the femoral shaft associated with aging may contribute to the initiation of varus-type OA of the knee. These changes in the femur may be followed by secondary signs of OA progression including varus femoral condylar orientation, medial joint space narrowing, and tibial plateau compression.

Arterial stiffness is increased in young women with endometriosis

Endometriosis is a chronic gynaecological disorder that is accompanied by inflammation and oxidative stress. Atherosclerosis has a long subclinical progression in arteries of children and young adults decades before overt clinical manifestations of the disease. In this study, we determined arterial stiffness by measuring brachial-ankle pulse wave velocity (baPWV) in women with endometriosis to assess the presence of subclinical atherosclerosis. We also measured markers of inflammation and oxidative stress in women with endometriosis. baPWV in women with endometriosis aged over 30 years was significantly higher than that in women without endometriosis aged over 30 years (p < 0.05), but not in women aged less than 30. Serum high-sensitivity C-reactive protein level in women with endometriosis was significantly higher than that in controls (p < 0.05). Young women with endometriosis show significantly increased arterial stiffness, suggesting that women with endometriosis need to be cautious of the future onset of atherosclerosis.

Site-specific changes in cytokine response to septic dose of lipopolysaccharide in ovariectomized female rats

PURPOSE

The immune response is altered according to hormonal and metabolic status. Obesity increases the inflammatory and fever response, whereas loss of gonadal steroid decreases behavioral response to immune stress. However, the immune systems of ovariectomized animals exhibiting obesity and gonadal steroid deficiency, particularly under septic conditions, have not been fully examined. In the present study, we evaluated the ovariectomy-induced changes of central and peripheral immune responses to life-threatening septic stimulus.

METHODS AND RESULTS

Ovariectomized rats showed heavier body weight and lighter uterine weight when compared with gonadally intact rats. Fever response to septic dose of lipopolysaccharide (LPS) in ovariectomized rats was less evident when compared with that in gonadally intact rats. In addition, under LPS-injected septic conditions, hypothalamic gene levels of Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and serum protein levels of IL-1β and TNF-α in ovariectomized rats were lower than those in gonadally intact rats. On the other hand, IL-6 levels in visceral fat under septic conditions were higher in ovariectomized rats than in gonadally intact rats.

CONCLUSIONS

These findings indicate that ovariectomy-induced site-specific changes in cytokine response under septic conditions. As hypothalamic, but not peripheral, pro-inflammatory cytokines are directly involved in the fever response, the attenuation of fever response observed in ovariectomized rats may be caused by a reduction in central cytokine responses.

Factors contributing to longitudinal changes in activities of daily living (ADL): The Koganei study

The present study is based on a 10-year observation of the completely competent elderly people aged 69-71 years in 1976, living at home. The purpose of the study is to identify predictors of incompetence in ADL at the follow-up carried out 10 years later. Among all the items of ADL, i.e., walking, eating, toileting, bathing, and dressing, the most remarkable decline was found in walking. The incompetent, those who suffered loss of independence on one or more items of ADL at follow-up, accouned for 32.4% of men and 25.6% of women. In the univariate logistic regression analysis, low levels of social activities in both sexes, history of hypertension and ECG abnormalities in men, and overweight and anxiety about present health status in women had a significant relationship to incompetence in ADL. The significance of social activities for both sexes was still observed in the multivariate analysis.

Effects of atrial natriuretic peptide on bicarbonate transport in long- and short-looped medullary thick ascending limbs of rats

Atrial natriuretic peptide (ANP) is known to influence NaCl transport in the medullary thick ascending limbs (MAL), where the largest NaCl reabsorption occurs among distal nephron segments in response to arginine vasopressin (AVP). In the present study, we investigated the effect of ANP on bicarbonate (HCO₃⁻) transport in the MAL using an isolated tubule perfusion technique. The HCO₃⁻ concentration was measured using free-flow ultramicro-fluorometer. We first observed basal HCO₃⁻ reabsorption in both long- and short-looped MALs (lMALs, and sMALs, respectively). AVP inhibited HCO₃⁻ reabsorption in both lMALs and sMALs, whereas ANP did not change HCO₃⁻ transport. However, in the presence of AVP, ANP restored the HCO₃⁻ reabsorption inhibited by AVP both in lMAL and sMAL. The effects of ANP on HCO₃⁻ transport was mimicked by cyclic GMP. The mRNA expression level of the vasopressin V2 receptor in lMALs was significantly higher than in sMALs, whereas expression of the V1a receptor was unchanged. In summary, AVP inhibits HCO₃⁻ transport, and ANP counteracts the action of AVP on HCO₃⁻ transport both in lMALs and sMALs.

Difference in the ratio of high-molecular weight (HMW) to total adiponectin and HMW adiponectin in late post-menopausal women

OBJECTIVE

High-molecular weight (HMW) isoform level and HMW ratio have been shown to be better predictors of insulin sensitivity and metabolic syndrome than total adiponectin level.We examined the changes in circulating levels of HMW adiponectin and ratios of HMW to total adiponectin in women during the menopausal transition.

METHODS

We conducted a cross-sectional study in 217 healthy women and divided them into 4 stages: 58 women in pre-menopausal, 69 women in perimenopausal, 62 women in early post-menopausal and 28 women in late post-menopausal phase. Serum levels of total adiponectin and HMW adiponectin were measured by an enzyme-linked immunosorbent assay.

RESULTS

In late post-menopausal women, HMW adiponectin level was significantly higher than that in peri-menopausal women and the HMW to total adiponectin ratio was significantly lower than that in early post-menopausal women. In peri-menopausal women, HMW adiponectin level was significantly lower than that in pre-menopausal women and HMW to total adiponectin ratio was significantly lower than the ratios in pre-menopausal and early post-menopausal women.

CONCLUSION

The ratio of HMW to total adiponectin is low in late post-menopausal women, though both levels of total and HMW adiponectin were high after menopause in our cross-sectional study.

The possibility of vertical transmission of human papillomavirus through maternal milk

Human papillomavirus (HPV) DNA has been detected in the oral cavity of infants and breast cancer tissue, suggesting its vertical transmission through maternal milk. We determined whether HPV is detected in maternal milk and is vertically transmitted by breast-feeding. Informed consent was obtained, and maternal milk samples (n=80) were analysed for high-risk HPV DNA. In 43 women, this DNA was measured in the uterine cervix. In women with positive samples, this DNA was measured in the oral cavities of their children. The domain including HPV E6 and E7 was amplified by polymerase chain reaction using consensus primers, and HPV serotype determined by electrophoresis after restriction enzyme digestion. High-risk HPV-16 was detected in two of 80 samples (2.5%), and in these two cases, high-risk HPV was not detected in the uterine cervix or oral cavity of the child. It was concluded that the infection of HPV in maternal milk is rare (2/80); vertical transmission through maternal milk was not detected in this study (0/80). HPV infection through maternal milk may occur, but its likelihood is low.

Association of Alzheimer disease pathology with abnormal lipid metabolism: the Hisayama Study

OBJECTIVE

The relationship between lipid profiles and Alzheimer disease (AD) pathology at the population level is unclear. We searched for evidence of AD-related pathologic risk of abnormal lipid metabolism.

METHODS

This study included brain specimens from a series of 147 autopsies performed between 1998 and 2003 of residents in Hisayama town, Japan (76 men and 71 women), who underwent clinical examinations in 1988. Lipid profiles, such as total cholesterol (TC), triglycerides, and high-density lipoprotein cholesterol (HDLC), were measured in 1988. Low-density lipoprotein cholesterol (LDLC) was calculated using the Friedewald formula. Neuritic plaques (NPs) were assessed according to the Consortium to Establish a Registry for Alzheimer's Disease guidelines (CERAD) and neurofibrillary tangles (NFTs) were assessed according to Braak stage. Associations between each lipid profile and AD pathology were examined by analysis of covariance and logistic regression analyses.

RESULTS

Adjusted means of TC, LDLC, TC/HDLC, LDLC/HDLC, and non-HDLC (defined as TC-HDLC) were significantly higher in subjects with NPs, even in sparse to moderate stages (CERAD = 1 or 2), compared to subjects without NPs in multivariate models including APOE ε4 carrier and other confounding factors. The subjects in the highest quartiles of these lipid profiles had significantly higher risks of NPs compared to subjects in the lower respective quartiles, which may suggest a threshold effect. Conversely, there was no relationship between any lipid profile and NFTs.

CONCLUSION

The results of this study suggest that dyslipidemia increases the risk of plaque-type pathology.

An EGFR inhibitor enhances the efficacy of SN38, an active metabolite of irinotecan, in SN38-refractory gastric carcinoma cells

BACKGROUND

Acquired drug resistance to irinotecan is one of the significant obstacles in the treatment of advanced gastric cancer. This study was performed to clarify the effect of epidermal growth factor receptor (EGFR) inhibitors in combination with SN38, an active metabolite of irinotecan, on the proliferation of irinotecan-refractory gastric cancer.

METHODS

Two irinotecan-resistant gastric cancer cell lines, OCUM-2M/SN38 and OCUM-8/SN38 were, respectively, established by stepwise exposure to SN38 from the parent gastric cancer cell lines OCUM-2M and OCUM-8. The combination effects of two EGFR inhibitors, gefitinib and lapatinib, with SN38 on proliferation, apoptosis, and cell cycle on gastric cancer cells were examined.

RESULTS

Gefitinib or lapatinib showed synergistic anti-tumour effects against OCUM-2M/SN38 and OCUM-8/SN38 cells when used in combination with SN38, but not against OCUM-2M or OCUM-8 cells. SN38 increased the expression of EGFR and HER2 in OCUM-2M/SN38 and OCUM-8/SN38 cells. The combination of an EGFR inhibitor and SN38 significantly increased the levels of apoptosis-related molecules, caspase-6, p53, and DAPK-2, and resulted in the induction of apoptosis of irinotecan-resistant cells. The EGFR inhibitors increased the S-phase and decreased the UGT1A1 and ABCG expression in irinotecan-resistant cells. The SN38 plus Lapatinib group more effectively suppressed in vivo tumour growth by OCUM-2M/SN38 cells than either alone group.

CONCLUSION

The combination treatment with an EGFR inhibitor and irinotecan might produce synergistic anti-tumour effects for irinotecan-refractory gastric cancer cells. The regulation of SN38 metabolism-related genes and cell cycle by EGFR inhibitors might be responsible for the synergism.

Beneficial effect of oral administration of Lactobacillus casei strain Shirota on insulin resistance in diet-induced obesity mice

AIMS

This study aimed at determining whether oral administration of a probiotic strain, Lactobacillus casei strain Shirota (LcS), can improve insulin resistance, which is the underlying cause of obesity-associated metabolic abnormalities, in diet-induced obesity (DIO) mice.

METHODS AND RESULTS

DIO mice were fed a high-fat diet without or with 0·05% LcS for 4 weeks and then subjected to an insulin tolerance test (ITT) or oral glucose tolerance test (OGTT). Oral administration of LcS not only accelerated the reduction in plasma glucose levels during the ITT, but also reduced the elevation of plasma glucose levels during the OGTT. In addition, plasma levels of lipopolysaccharide-binding protein (LBP), which is a marker of endotoxaemia, were augmented in the murine models of obese DIO, ob/ob, db/db and KK-A(y) and compared to those of lean mice. LcS treatment suppressed the elevation of plasma LBP levels in DIO mice, but did not affect intra-abdominal fat weight.

CONCLUSIONS

LcS improves insulin resistance and glucose intolerance in DIO mice. The reduction in endotoxaemia, but not intra-abdominal fat, may contribute to the beneficial effects of LcS.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study suggests that LcS has the potential to prevent obesity-associated metabolic abnormalities by improving insulin resistance.

Insulin resistance is associated with the pathology of Alzheimer disease: the Hisayama study

OBJECTIVE

We examined the association between diabetes-related factors and pathology of Alzheimer disease (AD) to evaluate how diabetes affects the pathogenic process of AD.

METHODS

This study included specimens from a series of 135 autopsies of residents of the town of Hisayama in Fukuoka prefecture (74 men and 61 women) performed between 1998 and 2003, who underwent a 75-g oral glucose tolerance test in clinical examinations in 1988. We measured diabetes-related factors including fasting glucose, 2-hour post-load plasma glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) in 1988. Neuritic plaques (NPs) were assessed according to the Consortium to Establish a Registry for Alzheimer's Disease guidelines and neurofibrillary tangles (NFTs) were assessed according to Braak stage. The associations between each factor and AD pathology were examined by analysis of covariance and logistic regression analyses.

RESULTS

Higher levels of 2-hour post-load plasma glucose, fasting insulin, and HOMA-IR were associated with increased risk for NPs after adjustment for age, sex, systolic blood pressure, total cholesterol, body mass index, habitual smoking, regular exercise, and cerebrovascular disease. However, there were no relationships between diabetes-related factors and NFTs. Regarding the effects of APOE genotype on the risk of AD pathology, the coexistence of hyperglycemia and APOE epsilon4 increased the risk for NP formation. A similar enhancement was observed for hyperinsulinemia and high HOMA-IR.

CONCLUSION

The results of this study suggest that hyperinsulinemia and hyperglycemia caused by insulin resistance accelerate NP formation in combination with the effects of APOE epsilon4.

Effects of intrauterine undernutrition on hypothalamic Kiss1 expression and the timing of puberty in female rats

Recent studies have suggested that intrauterine undernutrition is closely associated with the pathogenesis of diseases after birth. Perinatal undernutrition is known to disturb the development of reproductive function and delay the onset of puberty in some species. Using a rat model, we determined the effects of prenatal undernutrition on the development of the hypothalamic kisspeptin system and evaluated whether the alteration of the kisspeptin system contributes to the delayed onset of puberty induced by prenatal undernutrition. We also evaluated the effects of prenatal undernutrition on the developmental changes in serum leptin levels because leptin was a putative positive regulator of the hypothalamic kisspeptin system. We compared the timing of vaginal opening (VO) and the developmental changes in body weight, hypothalamic Kiss1 mRNA levels, and serum leptin concentrations between offspring with prenatal undernutrition (UN offspring) and normal nutrition (NN offspring). After birth, the UN offspring showed rapid growth and had caught up to body weight of the NN offspring by postnatal day 12. After postnatal day 16, the UN offspring showed significantly lower Kiss1 mRNA levels than the NN offspring, despite their significantly higher serum leptin levels (at days 20 and 28). The timing of VO in the UN offspring was delayed compared with that in the NN offspring, and chronic central injection of kisspeptin normalized the timing of VO in the UN offspring. These results suggest that decreased hypothalamic kisspeptin action contributes to the delayed onset of puberty in prenatally undernourished female rats. Increased leptin resistance in the kisspeptin system might be involved in these alterations.

Effects of VEGFR-3 phosphorylation inhibitor on lymph node metastasis in an orthotopic diffuse-type gastric carcinoma model

BACKGROUND

Vascular endothelial growth factor receptor-3 (VEGFR-3) signalling mediates lymphangiogenesis and lymphatic invasion; however, the effect of VEGFR-3 inhibition on the lymph node (LN) metastasis remains unclear. The aim of this study is to clarify the benefit of a VEGFR-3 inhibitor Ki23057 for LN metastasis.

METHODS

Ki23057 was administered orally to gastric cancer models created by orthotopic inoculation of diffuse-type gastric cancer cells, OCUM-2MLN. The effects of Ki23057 on lymphatic vessel invasion, lymphatic vessel density, and VEGFR-3 phosphorylation were examined by immunostaining or immunoblotting.

RESULTS

Ki23057 inhibited the autophosphorylation of VEGFR-3, with IC50 values of 4.3 nM in the cell-free kinase assay. Murine gastric cancer models created by the orthotopic inoculation of OCUM-2MLN cells showed the diffusely infiltrating growth and frequently developed LN metastasis. The oral administration of Ki23057 significantly (P<0.01) reduced the size of orthotopic tumours and the number of the metastatic LN in gastric cancer models. The degree of lymphatic invasion and lymphangiogenesis was significantly (P<0.05) lower in the gastric tumours treated by Ki23057. Ki23057 inhibited the phosphorylation of VEGFR-3 of lymphatic endothelial cells in gastric tumours.

CONCLUSION

The inhibition of lymphangiogenesis targeting VEGFR-3 phosphorylation is a therapeutic strategy for inhibiting LN metastasis of diffuse-type gastric cancer.

Enhanced renal accumulation of cisplatin via renal organic cation transporter deteriorates acute kidney injury in hypomagnesemic rats

BACKGROUND

This study aimed to explore the effects of hypomagnesemia on cisplatin (CDDP)-induced acute kidney injury (AKI) in rats and the relation of hypomagnesemia to the regulation of organic cation transporters and renal accumulation of CDDP.

METHODS

Sprague-Dawley rats were given an Mg-deficient diet starting 7 days before treatment with CDDP. CDDP was administered intravenously to rats in the normal Mg-diet group and Mg-deficient-diet group at 3 mg/kg via the left jugular vein. At the specified periods after injection of CDDP, the amount of platinum in blood and organ samples was determined using inductively coupled plasma-mass spectrometry. Protein expression levels of renal organic cation transporters were determined. Uptake of tetraethylammonium (TEA) bromide in renal slices of rats was measured.

RESULTS

Rats fed a Mg-deficient diet showed a significant body weight decrease and a marked decrease in serum Mg levels compared with control rats fed an adequate Mg diet. Serum blood urea nitrogen and creatinine levels were unaltered after CDDP treatment in control rats, whereas these levels were markedly elevated in hypomagnesemic rats. Immunoblotting revealed up-regulation of the organic cation transporter rOCT2 in hypomagnesemic rats before CDDP administration, but not of rOCT1 or rat multidrug and toxin-extrusion 1. TEA uptake by renal slices from hypomagnesemic rats was significantly higher compared with that of control rats. Renal accumulation of CDDP was markedly increased in hypomagnesemic rats.

CONCLUSION

These results suggest that hypomagnesemia could cause dehydration and up-regulation of rOCT2, enhancing renal accumulation of CDDP and the deterioration of AKI.