Rationale and protocol for a prospective cohort study of respiratory viral infections in patients admitted from emergency departments of community hospitals: Effect of respiratory Virus infection on EmeRgencY admission (EVERY) study.

INTRODUCTION: Respiratory syncytial virus (RSV) is a causative virus for the common cold worldwide and can result in hospitalisations and even death in patients with high-risk conditions and older adults. However, the relationship between RSV or other incidental respiratory infections and acute exacerbations of underlying conditions has not been well investigated. The primary objective of this study is to estimate RSV prevalence, risk factors for adverse outcomes or hospitalisation and their effect on the hospital course of patients with acute respiratory symptoms admitted from emergency departments. Furthermore, we evaluate the prevalence of other respiratory viruses associated with respiratory symptoms. METHODS AND ANALYSIS: We are conducting a multicentre prospective cohort study in Japan. We plan to enrol 3000 consecutive patients admitted from emergency departments with acute respiratory symptoms or signs from 1 July 2023 to 30 June 2024. A nasopharyngeal swab is obtained within 24 hours of admission and the prevalence of RSV and other respiratory viruses is measured using the FilmArray Respiratory 2.1 panel. Paired serum samples are collected from patients with suspected lower respiratory infections to measure RSV antibodies at admission and 30 days later. Information on patients' hospital course is retrieved from the electronic medical records at discharge, death or 30 days after admission. Furthermore, information on readmission to the hospital and all-cause mortality is collected 180 days after admission. We assess the differences in clinical outcomes between patients with RSV or other respiratory viruses and those without, adjusting for baseline characteristics. Clinical outcomes include in-hospital mortality, length of hospital stay, disease progression, laboratory tests and management of respiratory symptoms or underlying conditions. ETHICS AND DISSEMINATION: The study protocol was approved by the institutional review boards of participating hospitals. Our study reports will be published in academic journals as well as international meetings. TRIAL REGISTRATION NUMBER: NCT05913700.

The potential public health impact of the respiratory syncytial virus prefusion F protein vaccine in people aged ≥60 years in Japan: results of a Markov model analysis.

BACKGROUND: Respiratory syncytial virus (RSV), a common respiratory pathogen, can lead to severe symptoms, especially in older adults (OA). A recently developed RSV prefusion F protein (RSVPreF3 OA) vaccine confers high protection against RSV lower respiratory tract disease (LRTD) over two full RSV seasons. The aim of this study was to assess the potential public health impact of RSVPreF3 OA vaccination in the Japanese OA population. RESEARCH DESIGN AND METHODS: A static Markov model was used to estimate the number of symptomatic RSV cases, hospitalizations and deaths in the Japanese population aged ≥ 60 years over a 3-year time horizon. Japan-specific RSV epidemiology and healthcare resource use parameters were used; vaccine efficacy was derived from a phase 3 randomized study (AReSVi-006, NCT04886596). Vaccination coverage was set to 50%. RESULTS: Without vaccination, >5 million RSV acute respiratory illness (ARI) would occur (2.5 million LRTD and 2.8 million upper respiratory tract infections) leading to ~ 3.5 million outpatient visits, >534,000 hospitalizations and ~ 25,500 RSV-related deaths over 3 years. Vaccination could prevent > 1 million RSV-ARI cases, 728,000 outpatient visits, 143,000 hospitalizations and 6,840 RSV-related deaths. CONCLUSIONS: RSVPreF3 OA vaccination is projected to have a substantial public health impact by reducing RSV-related morbidity and mortality in the OA population.

Respiratory syncytial virus (RSV) is one of the most frequent disease-causing agents that leads to common cold symptoms. In older adults, infection with RSV can result in severe complications including bronchitis/bronchiolitis, lung infection (pneumonia) and in rare cases death. Older people and people with chronic heart or lung disease are more likely to experience complications. We estimated that more than 5 million RSV cases occur in older adults (≥60 years) over a three-year period (1.8 million over one year). Many older adults (≥60 years) will see their treating physician because of an acute RSV infection or will be hospitalized.Recently, a vaccine has been registered which protects older adults against RSV disease: the RSV prefusion F protein Older Adult (RSVPreF3 OA) vaccine. Vaccination with RSVPreF3 OA could prevent RSV infection in the older adult population and reduce the number of outpatient visits and hospitalizations; the impact is particularly high in Japan, where 35% of people are 60 years or older. We used a public health impact model to estimate how many RSV cases, hospitalizations and deaths could be prevented if 50% of people aged ≥ 60 years received the RSVPreF3 OA vaccine: We found that the vaccine could prevent about 1 million RSV infections, more than 728,000 outpatient visits, approximately 143,000 hospitalizations and 6,840 RSV-related deaths over a three-year period.Adding RSVPreF3 OA vaccine to the national immunization program in Japan could protect older adults against RSV disease and reduce the burden on patients and the healthcare system.

Health Status Progression Measured Using Weekly Telemonitoring of COPD Assessment Test Scores Over 1 Year and Its Association With COPD Exacerbations.

Background: A previous longitudinal study of chronic obstructive pulmonary disease (COPD) Assessment Test (CAT) score changes suggested patients fall into 3 patterns: stable, improving, and worsening. This study assessed the evolution of CAT scores over time and its relationship to exacerbations. Methods: In total, 84 participants used a telemedicine platform to complete CAT weekly for 52 weeks. Completion rates, annualized change in CAT scores, and learning effects were measured, as well as CAT changes of >4 units during look-back periods of 4 and 8 weeks. In a subgroup of participants with at least a 25% completion rate (adherent group, n=68 [81%]), the relationship between change in CAT score and exacerbations at any time during the study was examined post hoc. Results: Linear regression showed that 50%, 22%, and 28% of the adherent subgroup had CAT scores indicating worsening, stable, and improving health status, respectively. In the adherent subgroup, 70% (n=7/10) of participants who had an exacerbation during the study had worsening CAT scores, versus 47% (n=27/58) without an exacerbation. The hazard ratio association between CAT score increase and moderate exacerbation was 1.13 (95% confidence interval: 1.03-1.24). Most participants experienced at least one CAT score change of >4 units, and 7% showed an initial learning effect with a median of 2 weeks. Conclusion: Measuring trends in CAT scores may allow future studies to group patients into 3 defined categories of change over time and quantify CAT change trajectories to assess treatment response and potentially predict medium-term outcomes within individual patients.

A Telemedicine Approach for Monitoring COPD: A Prospective Feasibility and Acceptability Cohort Study.

Background: Telemedicine may help the detection of symptom worsening in patients with chronic obstructive pulmonary disease (COPD), potentially resulting in improved outcomes. This study aimed to determine the feasibility and acceptability of telemedicine among patients with COPD and physicians and facility staff in Japan. Methods: This was a 52-week multicenter, prospective, single-arm, feasibility and acceptability cohort study of Japanese patients ≥40 years of age with COPD or asthma-COPD overlap. Participants underwent training to use YaDoc, a telemedicine smartphone App, which included seven daily symptom questions and weekly COPD Assessment Test (CAT) questions. The primary endpoint was participant compliance for required question completion. The secondary endpoint was participant and physician/facility staff acceptability of YaDoc based on questionnaires completed at Week 52. The impact of the Japanese COVID-19 pandemic state of emergency on results was also assessed. Results: Of the 84 participants enrolled (mean age: 68.7 years, 88% male), 72 participants completed the study. Completion was high in the first six months but fell after that. Median (interquartile range [IQR]) compliance for daily questionnaire entry was 66.6% (31.0-91.8) and 81.0% (45.3-94.3) for weekly CAT entry. Positive participant responses to the exit questionnaire were highest regarding YaDoc ease of use (83.8%), positive impact on managing health (58.8%), and overall satisfaction (53.8%). Of the 26 physicians and facility staff enrolled, 24 completed the study. Of these, the majority (66.7%) responded positively regarding app facilitation of communication between physicians and participants to manage disease. Compliance was similar before and after the first COVID-19 state of emergency in Japan. Conclusion: Daily telemedicine monitoring is potentially feasible and acceptable to both patients and physicians in the management of COPD. These results may inform potential use of telemedicine in clinical practice and design of future studies. Clinical Trial Registration: JapicCTI-194916.

Cost-Effectiveness Analysis Update of the Adjuvanted Recombinant Zoster Vaccine in Japanese Older Adults.

INTRODUCTION: This study aimed to update cost-effectiveness and public health impact estimates of the two-dose recombinant zoster vaccine (RZV) compared with no vaccination against herpes zoster (HZ) in the Japanese population aged 65 years. List price of the vaccine and latest RZV efficacy and waning estimates were incorporated. METHODS: A multicohort static Markov model with a cycle length of 1 year was used to follow a hypothetical cohort of one million people aged 65 years over their remaining lifetime (base case). Age-stratified vaccine efficacy and waning rates were updated on the basis of the latest clinical trial data (interim ZOE-LTFU; NCT02723773). First-dose coverage was assumed at 40%, and second-dose compliance was assumed at 95%. Costs and outcomes were discounted at 2% annually, and the incremental cost-effectiveness ratio (ICER) was calculated from payer and societal perspectives. The societal perspective considered productivity loss due to suffering HZ, or due to suffering HZ and time required for vaccination. Sensitivity analyses explored the overall uncertainties in the model. Scenario analyses for Japanese adults aged 50, 60, 70, 80, ≥ 50, and ≥ 65 years (main scenario) were conducted. An ICER below ¥5-6 million/quality-adjusted life-year (QALY) was considered cost-effective. RESULTS: RZV was estimated to prevent 71,423 HZ cases and 15,858 post-herpetic neuralgia (PHN) cases per million people aged 65 years compared with no vaccine in Japan. The ICER was ¥4,205,515 from a payer perspective and was most sensitive to assumptions regarding vaccine efficacy waning, proportion of patients with HZ developing PHN, and HZ incidence. From societal perspectives, ICERs were ¥3,854,192 (productivity loss from suffering HZ only) and ¥4,622,212 (productivity loss from suffering HZ and time required for vaccination). Overall, the results were considered robust under extensive sensitivity and scenario analyses. CONCLUSION: Vaccination against HZ with RZV is cost-effective compared with no vaccination in Japanese adults aged 65 years.

MOONLIGHT study: the design of a comparative study of the effectiveness of belimumab in patients with a history of lupus nephritis from the post-Marketed effectiveness of belimumab cOhOrt and JapaN Lupus NatIonwide reGistry (LUNA) coHorT.

INTRODUCTION: Lupus nephritis (LN) is more prevalent in patients with SLE of Asian ethnicity than in Caucasian patients. Belimumab became available in Japan in 2017 to treat patients with SLE, including those with LN. In the BLISS-LN trial (NCT01639339), belimumab showed a favourable effect on renal outcomes when combined with standard therapy (ST) starting at the induction treatment phase for active LN, but real-world effectiveness of belimumab in LN has not been extensively studied. Here we describe the protocol for the MOONLIGHT (post-Marketed effectiveness of belimumab cOhOrt and JapaN Lupus NatIonwide ReGistry (LUNA) coHorT) study, which will use data from a Japan postmarketing surveillance study and the Lupus Registry of Nationwide Institutions (LUNA) to evaluate the real-world effectiveness of belimumab plus ST versus ST alone in patients with a history of active LN who are not in the induction phase. METHODS AND ANALYSIS: This multicentre, retrospective, observational study (GSK Study 214710) will enrol adults with SLE and a history of active LN, holding ≥3 years of complete follow-up data from the initiation of belimumab (no continuous treatment required). Data for patients with belimumab plus ST treatment (postmarketing registry data, belimumab cohort) will be compared with those for patients with ST only treatment (LUNA data, comparison cohort). Patients who discontinue/initiate belimumab after the start of the follow-up may be included in the comparison/belimumab cohort, respectively. The primary endpoint will be the occurrence of renal flares, for which belimumab's effectiveness will be estimated using a marginal structural model to consider time-dependent treatment and confounding factors. Secondary endpoints will include change in corticosteroid dose, renal disease activity, extrarenal disease activity, disease severity/activity biomarkers, LN class changes, end-stage kidney disease events and hospitalisations. ETHICS AND DISSEMINATION: This study will be conducted according to the Declaration of Helsinki and the local ethical guidelines. Findings will be submitted to peer-reviewed journals and presented at scientific meetings.

Risk of herpes zoster in the Japanese population with immunocompromising and chronic disease conditions: Results from a claims database cohort study, from 2005 to 2014.

Older adults, women and patients with immunocompromised (IC) or chronic medical conditions have a higher incidence of herpes zoster (HZ) and are at higher risk of developing HZ-associated complications such as postherpetic neuralgia. The incidence rates of HZ in various IC and chronic conditions have been previously reported in a retrospective cohort study using claims data from Japanese adults. Here, we report further analyses from this cohort using univariate and multivariable Cox regression to estimate crude and adjusted hazard ratios (HRs) associated with different IC and chronic conditions. After adjusting for multiple covariates (age, sex and other coexisting medical conditions), the risk of HZ was higher in women (HR, 1.14 [95% CI, 1.11-1.17]), irrespective of age and increased with increasing age, being substantially higher in patients aged 65 years or older (HR, 3.28 [95% CI, 3.07-3.49]) when compared with those aged 18-29 years. The highest HRs were observed for the following specific IC conditions; hematopoietic stem cell transplant recipients (HR, 9.85 [95% CI, 6.80-14.28]), hematological malignancy (HR, 3.22 [95% CI, 2.54-4.09]), systemic lupus erythematosus (HR, 2.46 [95% CI, 1.45-4.15]) and inflammatory bowel disease (HR, 1.59 [95% CI, 1.14-2.21]). For most other IC and chronic medical conditions, a higher risk was also apparent though of a smaller magnitude (HRs ranging from 1.2 to <1.5). These results corroborate our previous findings and demonstrate an increased risk of HZ associated with different IC and chronic conditions.

Burden of Herpes Zoster in the Japanese Population with Immunocompromised/Chronic Disease Conditions: Results from a Cohort Study Claims Database from 2005-2014.

INTRODUCTION: The aim of this study is to describe the disease burden and costs of herpes zoster (HZ) in the general adult Japanese population or patients with immunocompromised (IC) conditions or chronic disorders. METHODS: A retrospective cohort study of individuals aged 18-74 years was conducted using January 2005 to December 2014 records from the Japan Medical Data Center claims database. Twenty-eight IC conditions and chronic disorders were defined by diagnosis codes and/or procedures/treatments. HZ and its related complications were identified. Incidence rates (IR), frequency of HZ-related complications, healthcare resource utilization (HRU), and direct medical costs were estimated. HRU and costs were estimated on a subcohort of HZ cases occurring April 2012-January 2014. RESULTS: The overall IR of HZ in the total cohort of 2,778,476 adults was 4.92/1000 person-years (PY) [95% confidence interval (CI): 4.86-4.98] and increased with age. The IR in the IC cohort (51,818 subjects) was 8.87/1000 PY (95% CI: 8.29-9.48), ranging from 5.55/1000 PY (95% CI: 4.26-7.09) in psoriasis to 151.68/1000 PY (95% CI: 111.45-201.71) in hematopoietic stem cell transplant recipients; most IRs were in the range 6-10/1000 PY. The IRs in individuals with chronic disorders were also relatively high, in the range 5.40-12.90/1000 PY. The frequency of postherpetic neuralgia was 4.01% (95% CI: 3.72-4.33) in the total cohort and 11.73% (95% CI: 9.01-14.93) in the IC cohort. The mean [standard deviation (SD)] number of outpatient visits was 3.4 (4.9) and 5.0 (5.7), respectively, and the proportion of HZ patients hospitalized was 2.20% and 6.70%, respectively. The mean (SD) direct medical cost per HZ episode was ¥34,664 (¥54,433) and ¥55,201 (¥92,642) in the total and IC cohort, respectively. CONCLUSIONS: The elevated burden of HZ in Japanese individuals harboring IC conditions and chronic disorders documented in our study underlines the need for prevention of HZ in people with these conditions. FUNDING: GlaxoSmithKline Biologicals SA.

Disease severity and economic burden in Japanese patients with systemic lupus erythematosus: A retrospective, observational study.

AIM: To describe the healthcare resource utilization (HRU), direct medical costs and clinical characteristics for Japanese patients with mild, moderate or severe systemic lupus erythematosus (SLE). The primary objectives were to describe HRU and examine the direct medical costs for Japanese patients with mild, moderate, or severe SLE over the 3-year study period. Secondary objectives included recording patient demographics, clinical characteristics and frequency and cost of mild, moderate or severe flares. Exploratory objectives included a description of treatment patterns, and to explore which factors affect medical costs. METHODS: This retrospective, observational cohort study identified patients with SLE (diagnosed April 2010 to March 2012), from the Japan Medical Data Center claims database. RESULT: The study cohort comprised 295 patients with mild (28, 9.5%), moderate (134, 45.4%), or severe (133, 45.1%) SLE. Outpatient visits, hospitalizations and emergency room stays were experienced by 295 (100%), 116 (39.3%) and 31 (10.5%) patients, respectively, over the 3-year study period. Over the 3-year period, the mean total direct medical cost was US$27 004, and cost increased with SLE severity: mild, $5549 moderate, $15 290; and severe, $43 322 (analysis of variance, P < 0.0001). During this period, the majority of patients (282, 95.6%) experienced at least one flare episode and the mean (standard deviation) frequency was 5.5 (3.3) flares. The mean total direct medical cost per flare increased with SLE severity. CONCLUSION: This descriptive study provides information on the economic burden and clinical characteristics of Japanese patients with SLE based on claims data; high levels of HRU and direct medical costs were exhibited, particularly in patients with moderate or severe disease.

Impact of rotavirus vaccination on the burden of acute gastroenteritis in Nagoya city, Japan.

BACKGROUND: In Nagoya city, Japan, rotavirus (RV) vaccination has been available since 2011 with estimated coverage reaching 92% by 2015 after the introduction of a public subsidy in 2012. This study assessed the impact of vaccination on the RV gastroenteritis (RVGE) burden in children aged <5 years old (y) by comparing RVGE hospitalizations and outpatient visits during pre-vaccination (2007-2011), transition (2011-2012) and subsidization (2012-2016) periods. METHODS: All hospitalizations and outpatient visits in children aged <5 y from 2 administrative districts of Nagoya city were identified from the hospital-based electronic databases of 4 hospitals. RVGE cases were identified by diagnostic code and/or positive results of diagnostic kits. RESULTS: Compared to the pre-vaccination period, there was a decrease in RVGE hospitalizations for children <5 y from 5.59 per 1000 person-year (kPY) to 3.65/kPY in the subsidization period (i.e. 34.69%). In children <1 y, the incidence of RVGE hospitalizations decreased continuously from 6.62/kPY in the pre-vaccination period to 1.84/kPY in the subsidization period (i.e. 72.19%). The highest decrease was observed in the subsidization season i.e. when high coverage was reached: 69% and 75.57% in the 2013/2014 season for 2-3 y and 3-4 y, and 74.03% in the 2014/2015 season for 4-5 y, respectively. Proportion of RVGE outpatient visits decreased by 87.44% for children <1 y and 57.05% for <5 y from the pre-vaccination to the subsidization period. This decrease started the first year of subsidization for children <1 y, 1-2 y and 2-3 y (78.89%, 18.86% and 5.80%) and the second year (2013/2014 season) for children 3-4 y and 4-5 y (87.73% and 51.78%). CONCLUSIONS: Although yearly fluctuations have been observed, the introduction of vaccination significantly decreased pediatric RVGE hospitalizations and outpatient visits, especially in the age group eligible for vaccination. During the second and third year of subsidization, we observed a herd protection effect on other age groups <5 y who were not eligible for vaccination. Clinicaltrial.gov.registered#:NCT01733862.

Impact of Herpes Zoster and Post-Herpetic Neuralgia on Health-Related Quality of Life in Japanese Adults Aged 60 Years or Older: Results from a Prospective, Observational Cohort Study.

BACKGROUND AND OBJECTIVES: Herpes zoster (HZ) and its most frequent complication, post-herpetic neuralgia (PHN), have been shown to considerably impact quality of life (QoL). This has not yet been demonstrated in Japan. METHODS: QoL in HZ and PHN patients was evaluated using the Zoster Brief Pain Inventory (ZBPI), EuroQoL-5 Dimension (EQ-5D), Short-Form 12 version 2.0, and short-form McGill Pain Questionnaire up to 270 days after rash onset as part of a prospective, observational, cohort study conducted in Kushiro, Hokkaido, Japan. RESULTS: This study involved 412 adults ≥ 60 years of age diagnosed with HZ, 38 of whom developed PHN. QoL in daily activity performance and emotional and physical functioning was impaired at Day 0 (rash onset) and almost resolved by Day 90. Although the mean ZBPI worst pain score for HZ patients without PHN improved from 4.1 at Day 0 to 0.1 at Day 90, the score for HZ patients with PHN at Day 90 was comparable to that for HZ patients without PHN at Day 0. While the EQ-5D score in HZ without PHN improved, on average, from 0.755 to 0.949, the score for HZ with PHN was dependent on PHN duration and did not improve until PHN disappearance. CONCLUSIONS: HZ impaired QoL in daily activity performance and emotional and physical functioning. The negative impact on QoL was more prevalent in patients with a longer PHN duration compared with HZ without PHN. ClinicalTrials.gov identifier: NCT01873365.

Economic Burden of Herpes Zoster and Post-Herpetic Neuralgia in Adults 60 Years of Age or Older: Results from a Prospective, Physician Practice-Based Cohort Study in Kushiro, Japan.

BACKGROUND AND OBJECTIVE: Herpes zoster has a high incidence rate among people aged ≥ 60 years and can lead to serious complications such as post-herpetic neuralgia. There are currently no data on the economic burden of herpes zoster and post-herpetic neuralgia in Japan, and the objective of this study was to address this gap. METHODS: A total of 412 patients aged ≥ 60 years diagnosed with herpes zoster were recruited. Demographic, clinical, and healthcare resource utilization data on patients with herpes zoster or post-herpetic neuralgia collected via case report forms were used to estimate direct medical cost. Data obtained from a questionnaire survey among patients with herpes zoster/post-herpetic neuralgia were used to estimate transportation cost and productivity loss. RESULTS: The mean number of outpatient visits was 5.7. Prescription medications were the main cost driver accounting for 60% of the direct medical cost. The mean direct medical and total herpes zoster-related costs per patient were ¥43,925 and ¥57,112, respectively, and were higher in patients with post-herpetic neuralgia than in those with herpes zoster without complications. Direct medical cost represented 77%, productivity loss 19%, and transportation cost 4% of the total. CONCLUSIONS: This is the first study of the economic burden of herpes zoster and post-herpetic neuralgia in Japan and it demonstrated substantial direct medical cost as a result of the multiple outpatient visits and prescription medications required. These findings provide baseline data for possible future economic evaluations of new herpes zoster/post-herpetic neuralgia interventions. TRIAL REGISTRATION: This cost analysis is part of a prospective, physician practice-based cohort study conducted between June 2013 and February 2015 in Kushiro, Japan (Clinicaltrials.gov identifier NCT01873365, registered on 6 June, 2013).

Burden of herpes zoster and postherpetic neuralgia in Japanese adults 60 years of age or older: Results from an observational, prospective, physician practice-based cohort study.

Approximately one in three persons will develop herpes zoster during their lifetime, and it can lead to serious complications such as postherpetic neuralgia. However, evidence on burden of herpes zoster and postherpetic neuralgia in Japan is limited. This prospective, observational, multicenter, physician practice-based cohort study was conducted in Kushiro, Hokkaido, Japan (Clinicaltrials.gov identifier NCT01873365) to assess the incidence and hospitalization rates of herpes zoster, and the proportion, clinical burden and risk factors for postherpetic neuralgia in adults aged 60 years or more. Within the study area, 800 subjects developed herpes zoster and 412 were eligible for the study. Herpes zoster incidence was 10.2/1000 person-years and higher among women and older subjects. Subjects with herpes zoster required on average 5.7 outpatient consultations. Herpes zoster-associated hospitalization rate was 3.4% (27/800). The proportion of postherpetic neuralgia and other complications was 9.2% (38/412) and 26.5% (109/412), respectively. Statistically significant association with the development of postherpetic neuralgia was male sex (odds ratio [OR], 2.51; 95% confidence interval [CI], 1.17-5.38), age of 70-74 years (OR, 3.51; 95% CI, 1.09-11.3), immunosuppressive therapy (OR, 6.44; 95% CI, 1.26-32.9), severe herpes zoster pain at first consultation (OR, 3.08; 95% CI, 1.10-8.62) and rash on upper arms (vs no rash on upper arms; OR, 3.46; 95% CI, 1.10-10.9). Considerable herpes zoster and postherpetic neuralgia burden exists among elderly in Japan, and there may be predictive factors at the first visit which could be indicative of the risk of developing postherpetic neuralgia.

Deficiency of p62/Sequestosome 1 causes hyperphagia due to leptin resistance in the brain.

The cytoplasmic regulatory protein p62 (Sequestosome 1/A170) is known to modulate various receptor-mediated intracellular signaling pathways. p62 deficiency was shown to result in mature-onset obesity in mice, but the mechanisms underlying this abnormality remained unclear. Here we report that hyperphagia due to central leptin resistance is the cause of obesity in p62(-/-) mice. We found that these mice show hyperphagia. Restriction of food to the amount eaten by wild-type mice prevented excess body weight gain and fat accumulation, suggesting that overfeeding is the primary cause of obesity in p62(-/-) mice. Brain-specific p62 deficiency caused mature-onset obesity to the same extent as in p62(-/-) mice, further supporting a neuronal mechanism as the major cause of obesity in these mice. Immunohistochemical analysis revealed that p62 is highly expressed in hypothalamic neurons, including POMC neurons in the arcuate nucleus. Central leptin resistance was observed even in young preobese p62(-/-) mice. We found a defect in intracellular distribution of the transcription factor Stat3, which is essential for the action of leptin, in p62(-/-) mice. These results indicate that brain p62 plays an important role in bodyweight control by modulating the central leptin-signaling pathway and that lack of p62 in the brain causes leptin resistance, leading to hyperphagia. Thus, p62 could be a clinical target for treating obesity and metabolic syndrome.

TNF, but not IL-6 and IL-17, is crucial for the development of T cell-independent psoriasis-like dermatitis in Il1rn-/- mice.

IL-1 is a proinflammatory cytokine consisting of two molecular species, IL-1alpha and IL-1beta, and IL-1R antagonist (gene: Il1rn) is the endogenous suppressor. Il1rn(-/-) mice spontaneously develop autoimmune diseases, such as arthritis and aortitis, and a dermatitis that histologically resembles human psoriasis. The pathogenic mechanisms underlying this dermatitis, however, remain to be elucidated. In this study, we demonstrated that the production of inflammatory cytokines and chemokines was enhanced at the site of inflammation. The development of dermatitis was completely suppressed in Tnfsf1a(-/-) but not in Il6(-/-) mice, similar to that observed in arthritis and aortitis. However, IL-17 deficiency did not affect the development of dermatitis at all, in clear contrast to that of arthritis and aortitis. Different from arthritis and aortitis, adoptive transfer of Il1rn(-/-) T cells did not induce dermatitis in the recipient SCID mice and skin lesions developed in Il1rn(-/-) SCID mice, indicating that T cells are not involved in the development of skin lesions. In support for this, bone marrow cell transplantation experiments showed that TNF produced by skin residential cells, but not bone marrow cell-derived cells, was important for the development of dermatitis. Furthermore, we showed that IL-1 directly enhanced TNF and chemokine expression in keratinocytes. These observations suggest that excess IL-1 signaling directly activates keratinocytes to produce TNF and chemokines, resulting in the development of psoriasis-like skin lesions without the involvement of autoimmunity in Il1rn(-/-) mice.

Deficiency of interleukin-1 receptor antagonist induces aortic valve disease in BALB/c mice.

OBJECTIVE: Interleukin-1 receptor antagonist (IL-1Ra), one of the most important antiinflammatory cytokines, is crucial for homeostasis of the immune system. However, the role of IL-1Ra in aortic valve stenosis (AS) remains poorly understood [corrected]. METHODS AND RESULTS: IL-1Ra-deficient (IL-1Ra(-/-)) mice on the BALB/c background showed increased aortic valve leaflet thickness compared to wild-type mice at the age of 12 weeks (P<0.001). We used peripheral T-cell transplantation to examine the role of T cells in the development of AS. T cells from IL-1Ra(-/-) but not from wild-type mice induced increased aortic valve thickness in nu/nu mice. Moreover, IL-1Ra(-/-) T cells produced much higher levels of tumor necrosis factor (TNF)-alpha in culture supernatants after anti-CD3 antibody stimulation compared to wild-type mice (P<0.001). Finally, we studied the role of TNF-alpha in the development of AS in IL-1Ra(-/-) mice by generating double-gene-deficient (TNF-alpha(-/-)/IL-1Ra(-/-)) mice. Interestingly, TNF-alpha(-/-)/IL-1Ra(-/-) mice did not have AS. CONCLUSIONS: IL-1Ra deficiency in inflammatory cells induced aortic valve inflammation and TNF-alpha participates importantly in the development of AS in IL-1Ra(-/-) mice.

Selective loss of GABA(B) receptors in orexin-producing neurons results in disrupted sleep/wakefulness architecture.

Hypothalamic neurons that contain the neuropeptide orexin (hypocretin) play important roles in the regulation of sleep/wake. Here we analyze the in vivo and in vitro phenotype of mice lacking the GABA(B1) gene specifically in orexin neurons (oxGKO mice) and demonstrate that GABA(B) receptors on orexin neurons are essential in stabilizing and consolidating sleep/wake states. In oxGKO brain slices, we show that the absence of GABA(B) receptors decreases the sensitivity of orexin neurons to both excitatory and inhibitory inputs because of augmented GABA(A)-mediated inhibition that increases the membrane conductance and shunts postsynaptic currents in these neurons. This increase in GABA(A)-mediated inhibitory tone is apparently the result of an orexin receptor type 1-mediated activation of local GABAergic interneurons that project back onto orexin neurons. oxGKO mice exhibit severe fragmentation of sleep/wake states during both the light and dark periods, without showing an abnormality in total sleep time or signs of cataplexy. Thus, GABA(B) receptors on orexin neurons are crucial in the appropriate control of the orexinergic tone through sleep/wake states, thereby stabilizing the state switching mechanisms.

Orexins and orexin receptors: from molecules to integrative physiology.

Recent studies have implicated the orexin system as a critical regulator of sleep/wake states, feeding behavior, and reward processes. Orexin deficiency results in narcolepsy-cataplexy in humans, dogs, and rodents, suggesting that the orexin system is particularly important for maintenance of wakefulness. Orexin agonists and antagonists are thought to be promising avenues toward the treatment of sleep disorders, eating disorders, and drug addiction. In this chapter, we discuss the current understanding of the physiological roles of orexins in regulation of arousal, sleep/wake states, energy homeostasis, and reward systems.

IL-17 plays an important role in the development of experimental autoimmune encephalomyelitis.

IL-17 is a proinflammatory cytokine that activates T cells and other immune cells to produce a variety of cytokines, chemokines, and cell adhesion molecules. This cytokine is augmented in the sera and/or tissues of patients with contact dermatitis, asthma, and rheumatoid arthritis. We previously demonstrated that IL-17 is involved in the development of autoimmune arthritis and contact, delayed, and airway hypersensitivity in mice. As the expression of IL-17 is also augmented in multiple sclerosis, we examined the involvement of this cytokine in these diseases using IL-17(-/-) murine disease models. We found that the development of experimental autoimmune encephalomyelitis (EAE), the rodent model of multiple sclerosis, was significantly suppressed in IL-17(-/-) mice; these animals exhibited delayed onset, reduced maximum severity scores, ameliorated histological changes, and early recovery. T cell sensitization against myelin oligodendrocyte glycoprotein was reduced in IL-17(-/-) mice upon sensitization. The major producer of IL-17 upon treatment with myelin digodendrocyte glycopritein was CD4+ T cells rather than CD8+ T cells, and adoptive transfer of IL-17(-/-) CD4+ T cells inefficiently induced EAE in recipient mice. Notably, IL-17-producing T cells were increased in IFN-gamma(-/-) cells, while IFN-gamma-producing cells were increased in IL-17(-/-) cells, suggesting that IL-17 and IFN-gamma mutually regulate IFN-gamma and IL-17 production. These observations indicate that IL-17 rather than IFN-gamma plays a crucial role in the development of EAE.

Abnormal T cell activation caused by the imbalance of the IL-1/IL-1R antagonist system is responsible for the development of experimental autoimmune encephalomyelitis.

IL-1 is a pro-inflammatory cytokine that plays an important role in inflammation and host responses to infection. We have previously shown that imbalances in the IL-1 and IL-1R antagonist (IL-1Ra) system cause the development of inflammatory diseases. To explore the role of the IL-1/IL-1Ra system in autoimmune disease, we analyzed myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) in mice bearing targeted disruptions of the IL-1alpha, IL-1beta, IL-1alpha and IL-1beta (IL-1) or IL-1Ra genes. IL-1alpha/beta double-deficient (IL-1-/-) mice exhibited significant resistance to EAE induction with a significant reduction in disease severity, while IL-1alpha-/- or IL-1beta-/- mice developed EAE in a manner similar to wild-type mice. IL-1Ra-/- mice also developed MOG-induced EAE normally with pertussis toxin (PTx) administration. In contrast to wild-type mice, however, these mice were highly susceptible to EAE induction in the absence of PTx administration. We found that both IFN-gamma and IL-17 production and proliferation were reduced in IL-1-/- T cells upon stimulation with MOG, while IFN-gamma, IL-17 and tumor necrosis factor-alpha production and proliferation were enhanced in IL-1Ra-/- T cells. These observations suggest that the IL-1/IL-1Ra system is crucial for auto-antigen-specific T cell induction and contributes to the development of EAE.