Drug-drug interactions between letermovir and tacrolimus in Japanese renal transplant recipients simulated using a physiologically based pharmacokinetic model.

Letermovir (LET) is a novel antiviral agent recently approved for cytomegalovirus (CMV) prophylaxis of renal transplant patients in Japan. However, its interactions with tacrolimus (TAC), an important immunosuppressant, remain ambiguous, warranting careful evaluation considering the unique genetic and physiological characteristics of Japanese patients. Therefore, in this study, we aimed to investigate the drug-drug interactions between LET and extended-release TAC (ER-TAC) in Japanese renal transplant patients via physiologically based pharmacokinetic (PBPK) modeling. We developed PBPK models for LET and TAC, including a new model for ER-TAC, using the Simcyp simulator. We also created a virtual Japanese post-transplant population by incorporating physiological parameters specific to Japanese patients, including CYP3A5 genotypes. Our model accurately predicted the pharmacokinetics of both immediate-release and ER-TAC co-administered with LET. In the Japanese population, LET significantly increased ER-TAC exposure, with the effect varying by CYP3A5 genotype. For CYP3A5*1 carrier, the area under the curve ratio ranged from 2.33 to 2.53, while for CYP3A5*3/*3 carriers, it ranged from 2.82 to 2.86. The maximum concentration ratio was approximately 1.50 across all groups. Our findings suggest reducing the ER-TAC dose by approximately 57-60% for CYP3A5*1 carrier and 65% for CYP3A5*3/*3 carriers when co-administered with LET for Japanese renal transplant patients. Moreover, the developed model incorporating population-specific factors, such as hematocrit values and CYP3A5 genotype frequencies, is a valuable tool to evaluate complex drug interactions and guide the dosing strategies for LET and TAC in Japanese patients. Overall, this study expands the application of PBPK modeling in transplant pharmacology, contributing to the development of effective immunosuppressive strategies for Japanese renal transplant patients.

Development and validation of a prediction model for people with mild chronic kidney disease in Japanese individuals.

BACKGROUND: Chronic kidney disease (CKD) poses significant health risks due to its asymptomatic nature in early stages and its association with increased cardiovascular and kidney events. Early detection and management are critical for improving outcomes. OBJECTIVE: This study aimed to develop and validate a prediction model for hospitalization for ischemic heart disease (IHD) or cerebrovascular disease (CVD) and major kidney events in Japanese individuals with mild CKD using readily available health check and prescription data. METHODS: A retrospective cohort study was conducted using data from approximately 850,000 individuals in the PREVENT Inc. database, collected between April 2013 and April 2023. Cox proportional hazard regression models were utilized to derive and validate risk scores for hospitalization for IHD/CVD and major kidney events, incorporating traditional risk factors and CKD-specific variables. Model performance was assessed using the concordance index (c-index) and 5-fold cross-validation. RESULTS: A total of 40,351 individuals were included. Key predictors included age, sex, diabetes, hypertension, and lipid levels for hospitalization for IHD/CVD and major kidney events. Age significantly increased the risk score for both hospitalization for IHD/CVD and major kidney events. The baseline 5-year survival rates are 0.99 for hospitalization for IHD/CVD and major kidney events are 0.99. The developed risk models demonstrated predictive ability, with mean c-indexes of 0.75 for hospitalization for IHD/CVD and 0.69 for major kidney events. CONCLUSIONS: This prediction model offers a practical tool for early identification of Japanese individuals with mild CKD at risk for hospitalization for IHD/CVD and major kidney events, facilitating timely interventions to improve patient outcomes and reduce healthcare costs. The models stratified patients into risk categories, enabling identification of those at higher risk for adverse events. Further clinical validation is required.

A Prevalent TMEM260 Deletion Causes Conotruncal Heart Defects, Including Truncus Arteriosus.

Conotruncal heart defects are severe congenital malformations of the outflow tract, including truncus arteriosus (TA) and double-outlet right ventricle (DORV). TA is a severe congenital heart disease (CHD) in which the main arterial outflow tract of the heart fails to separate. We recently reported TMEM260 (NM_017799.4), c.1617del (p.Trp539Cysfs*9), as a major cause of TA in the Japanese population (TMEM260 Keio-Tohoku variant) comparable to the prevalence of the 22q11.2 deletion syndrome, which accounts for 12%-35% of TA. However, no other major causes of TA have not been identified. Here, we report a family that included a TA patient and a DORV patient, harboring the compound heterozygous variants of TMEM260, a 7066-bp deletion encompassing exons 6-7 and c.1393C > T, p.(Gln465*). The allele frequency of the 7066-bp deletion was particularly high in the Japanese population (0.17%). Based on the allele frequency of this deletion and c.1617del (0.36%) in the Japanese population, TMEM260 variants might be associated with more than half of the Japanese patients with TA. This study showed that TMEM260 pathogenic variants might be the most common cause of TA in the Japanese population and could explain the wide spectrum of phenotypes associated with TMEM260-related CHD, including DORV, demonstrating the usefulness of genetic testing in Japanese patients with TA.

Benefit of implantable cardioverter defibrillator use in Japanese patients based on modified MADIT-ICD benefit score.

AIMS: The MADIT-ICD benefit score is used to stratify the risk of life-threatening arrhythmia and non-arrhythmic mortality. We sought to develop an implantable cardioverter defibrillator (ICD) benefit-prediction score for Japanese patients with ICDs. METHODS: Patients who underwent ICD implantation as primary prophylaxis were retrospectively enrolled. Based on their MADIT-ICD benefit scores, we developed a modified MADIT-ICD benefit score adapted to the Japanese population. The primary endpoints were appropriate ICD therapy and all-cause death without appropriate ICD therapy (non-arrhythmic death). We used the Fine and Gray multivariate model and Cox proportional hazard regression to identify factors for adjusting the MADIT-ICD benefit-risk score specifically for the Japanese population. The scoring points for the original MADIT-ICD benefit score were adjusted to optimal points based on the multivariate analysis results in the population. RESULTS: The study enrolled 167 patients [age, 61.9 ± 12.3 years; male individuals, 138 (82.6%); cardiac resynchronization therapy, 73 (43.7%); ischaemic cardiomyopathy, 53 (31.7%)]. Fourteen patients received anti-tachycardia pacing (ATP) therapy, and 23 received shock therapy as the initial appropriate ICD therapy. Non-arrhythmic deaths occurred in 37 patients. The original MADIT-ICD benefit score could not stratify non-arrhythmic mortality in the Japanese population. The patients were reclassified into three groups according to the modified MADIT-ICD benefit score. The modified MADIT-ICD benefit score could effectively stratify the incidence of appropriate ICD therapy and non-arrhythmic mortality. In the highest-benefit group, the 10 year cumulative rates of appropriate ICD therapy and non-arrhythmic mortality were 56.8% and 12.9%, respectively (P < 0.01). In the intermediate-benefit group, these rates were 20.2% and 40.2% (P = 0.01). In the lowest-benefit group, the incidence of non-arrhythmic deaths was 68.1%, and no patient received appropriate ICD therapy. CONCLUSIONS: The modified MADIT-ICD benefit score may be useful for stratifying ICD candidates in the Japanese population.

Safety, reactogenicity, and immunogenicity of different doses of 10-valent Extraintestinal Pathogenic Escherichia Coli (ExPEC10V) bioconjugate vaccine (VAC52416) in healthy Japanese adults aged 60-85 years in a randomized, double-blind, phase 1 study.

AIM: This phase 1 study (NCT04306302) evaluated the safety, reactogenicity, and immunogenicity of ExPEC10V (VAC52416) in healthy Japanese adults. METHOD: The randomized, double-blind, single-center study included 28-day screening, vaccination (Day 1), 30-day safety and immunogenicity follow-up and 181-day serious adverse events (SAEs) follow-up. Participants (60-85 years) were enrolled in dose-ascending approach and randomized to medium- and high-doses of ExPEC10V (n = 8 in each dose group) and placebo (n = 8). Incidence of adverse events: solicited AEs (until Day 15), unsolicited AEs (until Day 30), SAEs (until Day 181) and immunogenicity (electrochemiluminescent-based assay [ECL] and multiplex opsonophagocytic assay [MOPA]) were assessed on Day 15 and Day 30. RESULTS: Total of 24 participants were included (median age, 66.5 years; 50.0 % female). Incidence of solicited AEs was 81.3 % (local) and 18.8 % (systemic) for pooled ExPEC10V group (medium-dose ExPEC10V: 75.0 % [local], 12.5 % [systemic]; high-dose ExPEC10V: 87.5 % [local], 25.0 % [systemic]). One SAE, not vaccine-related, was reported in high-dose ExPEC10V group after Day 30, which was resolved during study. The ECL demonstrated increase in binding antibody titers, which was maintained from Day 15 to Day 30. For all serotypes, the geometric mean fold increases from baseline on Day 15 ranged from 2.51 to 10.60 and 1.97-5.23 for medium- and high-dose groups, respectively. The MOPA demonstrated increase in functional antibody responses for all serotypes (except O8) at Day 15 which was maintained from Day 15 to Day 30. CONCLUSIONS: ExPEC10V medium- and high-doses were well tolerated with an acceptable safety profile without any significant safety issues in healthy Japanese participants.

Initial validation of the clinical significance of the NETest in Japanese gastroenteropancreatic neuroendocrine tumor patients.

As novel biomarkers for gastroenteropancreatic neuroendocrine tumors (GEPNET) are in demand, we aimed to validate the clinical value of the NETest in Japanese patients. Between 2021 and 2023, blood and clinical data were collected from patients with GEPNET. Among 35 patients (median age: 59 [49-66] years), 27 cases originated from the pancreas and eight from the gastrointestinal tract. Of 69 samples sent to the laboratory, 56 (81.2%) underwent NETest. The diagnostic sensitivity was 97.1%. Among three patients who underwent R0 resection and four treated with peptide receptor radionuclide therapy, the changes in NETest scores closely correlated with disease progression. The NETest demonstrated high diagnostic efficacy and accurate therapeutic monitoring capabilities in a Japanese population.

Genome-Wide Association Study with Three Control Cohorts of Japanese Patients with Esotropia and Exotropia of Comitant Strabismus and Idiopathic Superior Oblique Muscle Palsy.

Esotropia and exotropia in the entity of comitant strabismus are multifactorial diseases with both genetic and environmental backgrounds. Idiopathic superior oblique muscle palsy, as the predominant entity of non-comitant (paralytic) strabismus, also has a genetic background, as evidenced by varying degrees of muscle hypoplasia. A genome-wide association study (GWAS) was conducted of 711 Japanese patients with esotropia (n= 253), exotropia (n = 356), and idiopathic superior oblique muscle palsy (n = 102). The genotypes of single nucleotide polymorphisms (SNPs) were determined by Infinium Asian Screening Array. Three control cohorts from the Japanese population were used: two cohorts from BioBank Japan (BBJ) and the Nagahama Cohort. BBJ (180K) was genotyped by a different array, Illumina Infinium OmniExpressExome or HumanOmniExpress, while BBJ (ASA) and the Nagahama Cohort were genotyped by the same Asian array. After quality control of SNPs and individuals, common SNPs between the case cohort and the control cohort were chosen in the condition of genotyping by different arrays, while all SNPs genotyped by the same array were used for SNP imputation. The SNPs imputed with R-square values ≥ 0.3 were used to compare the case cohort of each entity or the combined entity with the control cohort. In comparison with BBJ (180K), the esotropia group and the exotropia group showed CDCA7 and HLA-F, respectively, as candidate genes at a significant level of p < 5 × 10-8, while the idiopathic superior oblique muscle palsy group showed DAB1 as a candidate gene which is involved in neuronal migration. DAB1 was also detected as a candidate in comparison with BBJ (ASA) and the Nagahama Cohort at a weak level of significance of p < 1 × 10-6. In comparison with BBJ (180K), RARB (retinoic acid receptor-ß) was detected as a candidate at a significant level of p < 5 × 10-8 in the combined group of esotropia, exotropia, and idiopathic superior oblique muscle palsy. In conclusion, a series of GWASs with three different control cohorts would be an effective method with which to search for candidate genes for multifactorial diseases such as strabismus.

Prognostic significance of chronic kidney disease and impaired renal function in Japanese patients with COVID-19.

BACKGROUND: Renal impairment is a predictor of coronavirus disease (COVID-19) severity. No studies have compared COVID-19 outcomes in patients with chronic kidney disease (CKD) and patients with impaired renal function without a prior diagnosis of CKD. This study aimed to identify the impact of pre-existing impaired renal function without CKD on COVID-19 outcomes. METHODS: This retrospective study included 3,637 patients with COVID-19 classified into three groups by CKD history and estimated glomerular filtration rate (eGFR) on referral: Group 1 (n = 2,460), normal renal function without a CKD history; Group 2 (n = 905), impaired renal function without a CKD history; and Group 3 (n = 272), history of CKD. We compared the clinical characteristics of these groups and assessed the effect of CKD and impaired renal function on critical outcomes (requirement for respiratory support with high-flow oxygen devices, invasive mechanical ventilation, or extracorporeal membrane oxygen, and death during hospitalization) using multivariable logistic regression. RESULTS: The prevalence of comorbidities (hypertension, diabetes, and cardiovascular disease) and incidence of inflammatory responses (white blood counts, and C-reactive protein, procalcitonin, and D-dimer levels) and complications (bacterial infection and heart failure) were higher in Groups 2 and 3 than that in Group 1. The incidence of critical outcomes was 10.8%, 17.7%, and 26.8% in Groups 1, 2, and 3, respectively. The mortality rate and the rate of requiring IMV support was lowest in Group 1 and highest in Group 3. Compared with Group 1, the risk of critical outcomes was higher in Group 2 (adjusted odds ratio [aOR]: 1.32, 95% confidence interval [CI]: 1.03-1.70, P = 0.030) and Group 3 (aOR: 1.94, 95% CI: 1.36-2.78, P < 0.001). Additionally, the eGFR was significantly associated with critical outcomes in Groups 2 (odds ratio [OR]: 2.89, 95% CI: 1.64-4.98, P < 0.001) and 3 (OR: 1.87, 95% CI: 1.08-3.23, P = 0.025) only. CONCLUSIONS: Clinicians should consider pre-existing CKD and impaired renal function at the time of COVID-19 diagnosis for the management of COVID-19.

Y chromosome haplogroups are associated with birth size in Japanese men.

The Y chromosome is classified into haplogroups (A-T) based on a combination of several DNA polymorphisms. Japanese men are mainly classified into haplogroups C, D, and O, which have been further subdivided. The distribution of Y-chromosome haplogroups varies by ethnicity. The phylogenetic age, origin, and migration also differ. I hypothesized that Y chromosome haplogroups may be associated with height and/or weight at birth. An association analysis of height and weight at birth with Y chromosome haplogroups was performed in 288 Japanese men. Men belonging to haplogroup O1b2 were significantly associated with short stature at birth (beta = －1.88, standard error (SE) = 0.55, P = 0.00076), and those belonging to D1a2a-12f2b were significantly associated with increased birth weight (beta = 174, SE = 64, P = 0.0069). Y chromosome haplogroups are associated with physical birth characteristics in modern Japanese men. J. Med. Invest. 71 : 129-133, February, 2024.

A single arm Phase I/II trial on the combination of carboplatin, nab-paclitaxel and avastin as first-line treatment for advanced non-squamous non-small cell lung cancer (TORG1424/OLCSG1402: CARNAVAL).

BACKGROUND: Bevacizumab with platinum doublet therapy including paclitaxel + carboplatin improves the survival of patients with non-squamous non-small cell lung cancer. However, in a previous trial (CA031), paclitaxel + carboplatin led to Grade > 3 neutropenia in a Japanese population. Nanoparticle albumin-bound paclitaxel exhibits an improved toxicity profile. We evaluated the safety, dosage and response rate of the nanoparticle albumin-bound paclitaxel + carboplatin + bevacizumab combination in a Japanese population. METHODS: Chemotherapy-naive patients with advanced non-squamous non-small cell lung cancer were included. The dosage schedule was established in the Phase I trial as follows: 4-6 cycles of carboplatin (area under the concentration-time curve = 6 on Day 1) + nanoparticle albumin-bound paclitaxel (100 mg/m2 on Days 1, 8 and 15) + bevacizumab (15 mg/kg on Day 1), followed by maintenance therapy (nanoparticle albumin-bound paclitaxel + bevacizumab). The response rate and presence of adverse effects were evaluated in the Phase II trial. RESULTS: The overall response rate was 56.5% (90% confidence interval: 44.5-68.5), and 93% of patients (43/46) showed tumor shrinkage or maintained a stable disease course. The primary endpoint was achieved. At the median follow-up duration of 42 months, the median overall survival was 18.9 (range: 10.5-32.4) months. The most frequently observed Grade ≥ 3 adverse effects were neutropenia (72%), leukopenia (50%) and anemia (30%). CONCLUSIONS: All adverse effects were manageable and none resulted in patient death. In conclusion, the nanoparticle albumin-bound paclitaxel + carboplatin + bevacizumab combination is favorable and well tolerated in Japanese patients as first-line treatment for advanced non-squamous non-small cell lung cancer.

Bloodstream infections in the elderly Japanese population: Current reality and countermeasures.

We reviewed bloodstream infections in the elderly in Japan, referring to data recently reported from the National Center for Global Health and Medicine in Tokyo. We divided the locations of bloodstream infections into Hospital-onset (HO), healthcare-associated (HCA), and CA (community-acquired), as the elderly reside in different places. The study focused on the fact that the general condition and underlying diseases of the elderly differ by age group. And thus, we divided them into three groups: Pre-old (65-74 years), Old (75-89 years), and Super-old (≥ 90 years), and compared their characteristics of bloodstream infections. HO bacteremia was most common in the pre-old group. On the other hand, HCA bloodstream infections tended to increase as the population aged, and it was most prevalent in super-old group. According to the study results, early intervention through infectious diseases (ID) consultation may improve the prognosis of bloodstream infections even in the elderly. Since the rate of ID consultation is lower in the super-old group than in other groups, this group may be a significant target. In conclusion, a study of a cohort of elderly patients with bloodstream infections in Japan indicates that bloodstream infections in patients over 65 years is not uniform.

Alcohol and toxicological factors influencing fatal falls from height in the Greater Tokyo Area: a retrospective study.

Falls from height pose a significant public health concern in urban regions, including the highly urbanized Greater Tokyo Area. The Japanese population is characterized by high rates of suicide and psychoactive drug usage, underscoring the importance of investigating these attributes in falls from height. This study aimed to retrospectively analyze the alcohol and toxicological aspects influencing falls from height in the Greater Tokyo Area between 2014 and 2022 and compare the findings with existing reports on other populations. In total, 75 cases of falls from height and 159 cases of natural deaths were included. Consistent with previous findings, Fisher's exact test revealed a predominance of males (66.67%, 50/75) and young adults (57.33%, 43/75) in falls from height. Multivariate logistic regression analysis identified antidepressant usage as the most significant risk factor within the target population, while younger individuals under alcohol influence constituted another high-risk group. Notably, contradictory to other populations, female individuals involved in fatal falls in the Greater Tokyo Area exhibited a higher frequency of alcohol consumption than males (48.00%, 12/25 vs. 26.00%, 13/50), and most of them were associated with suicide (83.33%, 10/12). These findings elucidate the population characteristics that pose a high risk for fatal falls from height in Japan and can serve as a reference for other Asian populations residing in similar megacities.

Development and Validation of Prediction Models for the 5-year Risk of Type 2 Diabetes in a Japanese Population: Japan Public Health Center-based Prospective (JPHC) Diabetes Study.

BACKGROUND: This study aimed to develop models to predict the 5-year incidence of type 2 diabetes mellitus (T2DM) in a Japanese population and validate them externally in an independent Japanese population. METHODS: Data from 10,986 participants (aged 46-75 years) in the development cohort of the Japan Public Health Center-based Prospective Diabetes Study and 11,345 participants (aged 46-75 years) in the validation cohort of the Japan Epidemiology Collaboration on Occupational Health Study were used to develop and validate the risk scores in logistic regression models. RESULTS: We considered non-invasive (sex, body mass index, family history of diabetes mellitus, and diastolic blood pressure) and invasive (glycated hemoglobin [HbA1c] and fasting plasma glucose [FPG]) predictors to predict the 5-year probability of incident diabetes. The area under the receiver operating characteristic curve was 0.643 for the non-invasive risk model, 0.786 for the invasive risk model with HbA1c but not FPG, and 0.845 for the invasive risk model with HbA1c and FPG. The optimism for the performance of all models was small by internal validation. In the internal-external cross-validation, these models tended to show similar discriminative ability across different areas. The discriminative ability of each model was confirmed using external validation datasets. The invasive risk model with only HbA1c was well-calibrated in the validation cohort. CONCLUSION: Our invasive risk models are expected to discriminate between high- and low-risk individuals with T2DM in a Japanese population.

The Relationship Between PD-1(rs2227981) and PD-L1(rs2890658) Polymorphisms and Urothelial Cell Carcinoma.

Background Urothelial cell carcinoma, which is believed to develop from the urothelium (transitional epithelium), is the most common aggressive tumor and accounts for the ten most prevalent cancers in the world. The risk factors for urothelial cell carcinoma are aging, smoking, gender, and genetic alternations. Programmed cell death1 (PD-1) has been widely described as a negative regulator of T-cells by sending inhibitory signals to the T-cell. Through PD-1 binding with PD-L1 (ligand for PD-1), an inhibitory signal is propagated to the T cell. The polymorphisms of PD-1 and PD-L1 lead to an efficient T-cell response and affect an anti-tumor reaction. The polymorphisms of PD-1 and PD-L1 could also affect the carcinogenesis of human cancer, including urothelial cell carcinoma. Therefore, in this study, we evaluated the relation between PD-1(rs2227981) and PD-L1(rs2890658) polymorphisms and the carcinogenesis of urothelial cell carcinoma. Materials and methods This study was conducted using 211 healthy controls and 256 cases of urothelial cell carcinoma among the Japanese population. The DNA samples were extracted from the peripheral white blood cells of each subject. The genotype was detected by using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Results C/T (Adjusted OR 1.55, 95% CI:1.02-2.35) and C/T+T/T (OR 1.46, 95% CI:1.01-2.12) genotypes of PD-1 rs2227981 were significant and risk factors for urothelial cancer. Male with A/A genotype in PD-L1 and CT genotype in PD-1 has a significant higher risk factor compared with other genotypes (Adjusted OR 1.83, 95% CI:1.05-3.21). Conclusions and discussion We found that C/T(PD-1) and "A/A (PD-L1) and C/T(PD-1)" were predominant in urothelial cell carcinoma cases. This indicates that C/T(PD-1) and "A/A (PD-L1) and C/T(PD-1)" genotypes could increase susceptibility to urothelial cell carcinoma. However, since our findings indicated that the effects of PD-1 and PD-L1 polymorphisms included discrepancies, additional research will be needed to evaluate the relationship between human cancer and PD-1 and PD-L1 polymorphisms. This is the first study that seeks to find the relation between PD-1(rs2227981) and PD-L1(rs2890658) polymorphisms concerning urothelial cell carcinoma among the Japanese population.

Identifying Clusters of Health Behaviors in a Japanese Working Population at Risk for Non-Communicable Diseases: A Latent Class Analysis of 12,168 Individuals.

Introduction: Noncommunicable diseases (NCDs) have become a significant global problem. Health behaviors are associated with NCDs, and characterizing populations using a public health approach can help provide specific interventions according to their characteristics. This study aims to examine the formation of clusters of health behavior combinations in the Japanese working population at risk of NCDs, taking into account the influences of age and gender, using latent class analysis. Methods: Participants were individuals at risk for NCDs but had not previously been diagnosed with any. Latent class analysis (LCA) was used to study clustering based on basic characteristics and health behaviors. All statistical analyses were conducted using R (Version 4.0.4) and the "poLCA" package (Version 1.6.0). Results: This study included 12,168 participants. LCA compared models with one to six latent classes. The five-class model was determined to be the most appropriate based on Bayesian Information Criterion, Akaike Information Criterion, and G^2 values, as well as distinguishable cluster characteristics. Cluster 1: "having healthy lifestyles but disliking hospitals"; Cluster 2: "women with healthy lifestyle behaviors"; Cluster 3: "general population"; Cluster 4: "middle-aged group in need of lifestyle improvement"; Cluster 5: "a group receiving treatment for lifestyle-related diseases." Conclusions: This study reveals discernible health behavior patterns in a sample of the Japanese population using large real-world data, suggesting the effectiveness of distinct approaches when considering a population approach to public health.

The association between masticatory ability and lower Timed Up & Go Test performance among community-dwelling Japanese aging men and women: The Toon Health Study.

Objectives: Few studies examined the association between deterioration of masticatory ability assessed by objective marker and physical function. Therefore, we examined the association between salivary flow rate which is one of the objective and surrogate marker of masticatory ability and lower Timed Up & Go (TUG) performance which is one of major measurement of physical function among aging Japanese. Methods: This cross-sectional study enrolled 464 Japanese aged 60-84 years old. Participants chewed tasteless and odorless gum for 5 min, calculated stimulated salivary flow rate (g/min) during all chews. The 3 m TUG was conducted, and 75th percentile value (6.8 s for men and 7.0 s for women) or higher was defined as lower TUG performance. Logistic regression analysis was used to examine the association between stimulated salivary flow rate and lower TUG performance. Results: We found that the stimulated salivary flow rate tended to be negatively associated with the TUG time. We also observed significant negative association between stimulated salivary flow rate and lower TUG performance; the multivariable-adjusted OR (95% confidence interval, CIs) of lower TUG performance for the highest quartile of stimulated salivary flow rate compared with the lowest quartile was 0.34 (0.16-0.69, P for trend = 0.02). Further adjusting for BMI, the association was attenuated but remaind significant; the OR (95% CIs) in highest quartile was 0.37 (0.18-0.76, P for trend = 0.04). Conclusions: Higher stimulated salivary flow, which means well masticatory ability, was inversely associated with lower TUG performance in the aging Japanese population.

Proposed reference intervals of serum insulin-like growth factor-1 (IGF-1) levels in older Japanese populations.

Measurements of serum insulin-like growth factor 1 (IGF-1) levels are useful surrogate markers for the diagnosis and management of patients with growth hormone-related disorders. We have previously published normative data of serum IGF-1 levels for the Japanese population aged 0-77 years by combining and analyzing previously reported references, which were separately and independently constructed, to properly reflect data in the transition period. Although the reference is widely used in both clinical and research settings, the reference did not include data for those aged >77 years, raising the question of how we would evaluate patients over those ages. In this study, we extended the age- and sex-specific reference ranges of serum IGF-1 levels to the age of 80 years by reanalyzing combined data on serum IGF-1 levels from previously published references. Based on our results, we proposed that individuals aged >80 years can be evaluated using the references set at the age of 80 years. However, our proposal was based on a very limited number of participants. Therefore, physicians should exercise caution when interpreting IGF-1 standard deviation scores for those aged >80 years because they are not exactly correct but acceptable.

Estimation of missing mandible from the skull using postmortem CT images.

Skeletal remains often have missing mandibles owing to the environment in which the corpse was placed or damage caused by an animal. Loss of the mandible reduces the accuracy of skull identification. Although several studies have validated methods for estimating mandibular morphology from conventional anthropological measurements using skull specimens, there are no reports using three-dimensional computed tomography (3DCT) images. Here, we examined methods for establishing the mandibular morphology from the remaining skulls using postmortem computed tomography (PMCT) images. We used PMCT images from 200 Japanese subjects as samples. After verifying the morphological correlation between the cranium and mandible, we created and validated estimation models using multiple regression analysis (stepwise method) for seven sites that were necessary for understanding the morphology of the mandible. Among the regression models, the estimated model for bicondylar breadth had the highest coefficient of determination (adjR2 = 0.53). We verified the accuracy of the model on a sample independent from the specimen used to create the estimation model and found that the formulated model of bicondylar breadth had good estimation accuracy, with a high correlation coefficient between the measured and predicted values of 0.82 and a mean absolute error of 3.582 mm, indicating that the model had good estimation accuracy. Here, we established a novel method for estimating the missing mandibular morphology based on PMCT data from the Japanese population. Our estimation model can help determine the missing mandibular morphology in a cranium remnant.

Association between ABO blood group/genotype and COVID-19 in a Japanese population.

An association between coronavirus disease 2019 (COVID-19) and the ABO blood group has been reported. However, such an association has not been studied in the Japanese population on a large scale. Little is known about the association between COVID-19 and ABO genotype. This study investigated the association between COVID-19 and ABO blood group/genotype in a large Japanese population. All Japanese patients diagnosed with COVID-19 were recruited through the Japan COVID-19 Task Force between February 2020 and October 2021. We conducted a retrospective cohort study involving 1790 Japanese COVID-19 patients whose DNA was used for a genome-wide association study. We compared the ABO blood group/genotype in a healthy population (n = 611, control) and COVID-19 patients and then analyzed their associations and clinical outcomes. Blood group A was significantly more prevalent (41.6% vs. 36.8%; P = 0.038), and group O was significantly less prevalent (26.2% vs. 30.8%; P = 0.028) in the COVID-19 group than in the control group. Moreover, genotype OO was significantly less common in the COVID-19 group. Furthermore, blood group AB was identified as an independent risk factor for most severe diseases compared with blood group O [aOR (95% CI) = 1.84 (1.00-3.37)]. In ABO genotype analysis, only genotype AB was an independent risk factor for most severe diseases compared with genotype OO. Blood group O is protective, whereas group A is associated with the risk of infection. Moreover, blood group AB is associated with the risk of the "most" severe disease.

Genome-wide association studies in the Japanese population identified genetic loci and target gene associated with epidermal turnover.

The epidermis is an essential organ for life by retaining water and as a protective barrier. The epidermis is maintained through metabolism, in which basal cells produced from epidermal stem cells differentiate into spinous cells, granular cells and corneocytes, and are finally shed from the epidermal surface. This is epidermal turnover, and with aging, there is a decline in epidermis function. Other factors that may affect epidermal turnover include ultraviolet damage and genetic factors. These genetic factors are of particular interest as little is known. Although recent skin-focused genome-wide association studies (GWAS) have been conducted, the genetic regions associated with epidermal turnover are almost uninvestigated. Therefore, we conducted a GWAS on epidermal turnover in the Japanese population, using the corneocyte area, which correlates to the rate of epidermal turnover, as an indicator. As a result, rs2278431 (p = 1.29 × 10-7 ) in 19q13.2 was associated with corneocyte size. Furthermore, eQTL analysis suggested that rs2278431 was related to the SPINT2 gene. In addition, SPINT2 knockdown studies using epidermal keratinocytes revealed that SPINT2 is involved in keratinocyte proliferation and in corneocyte size regulation in reconstructed epidermis. These results suggest that rs2278431 is involved in the expression of SPINT2 and affects epidermal turnover.