Quantification of lipoprotein lipase in mouse plasma with a sandwich enzyme-linked immunosorbent assay.

To support in vivo and in vitro studies of intravascular triglyceride metabolism in mice, we created rat monoclonal antibodies (mAbs) against mouse LPL. Two mAbs, mAbs 23A1 and 31A5, were used to develop a sandwich ELISA for mouse LPL. The detection of mouse LPL by the ELISA was linear in concentrations ranging from 0.31 ng/ml to 20 ng/ml. The sensitivity of the ELISA made it possible to quantify LPL in serum and in both pre-heparin and post-heparin plasma samples (including in grossly lipemic samples). LPL mass and activity levels in the post-heparin plasma were lower in Gpihbp1-/- mice than in wild-type mice. In both groups of mice, LPL mass and activity levels were positively correlated. Our mAb-based sandwich ELISA for mouse LPL will be useful for any investigator who uses mouse models to study LPL-mediated intravascular lipolysis.

Revised Cut-Off Value of Human Epididymis Protein 4 Enhances Its Use as an Ovarian Tumor Marker.

OBJECTIVES: Human epididymis protein 4 (HE4), a protein secreted by ovarian tumors, has been used as an ovarian tumor marker. This study aimed to improve the usefulness of HE4 to detect malignant ovarian tumors by reviewing the cut-off values. DESIGN: A retrospective study without intervention was conducted. PARTICIPANTS: One hundred forty-nine healthy women (premenopausal, 126; postmenopausal, 23) and 24 patients with ovarian tumors (malignant, 12; benign, 12) participated in the study. SETTING: The study used the Department of Obstetrics and Gynecology of a university hospital in Japan and the university hospital as a workplace from 2016 to 2018. METHODS: The basic performance of the HE4 assay was evaluated, and the serum HE4 levels of participants were measured. Receiver operating characteristic analysis was performed using the HE4 data of the patients. RESULTS: There were no significant differences in HE4 levels between the pre- and postmenopausal groups of healthy women. When the global cut-off values (premenopausal, 70 pmol/L; postmenopausal, 140 pmol/L) were adopted, the clinical sensitivity, specificity, positive predictive value, and negative predictive value were 41.7%, 91.7%, 83.3%, and 61.1%, respectively. Based on the results of the receiver operating characteristic analysis, we set the HE4 cut-off level at 60 pmol/L, regardless of the menopausal status. With the newly set cut-off value, the clinical sensitivity, specificity, positive predictive value, and negative predictive value were 66.7%, 91.7%, 88.9%, and 73.3%, respectively. That is, the clinical sensitivity of HE4 was improved without lowering specificity. LIMITATIONS: The small number of subjects and the fact that the health status of the healthy women was evaluated based on questionnaires were limitations to the study. CONCLUSION: A clinically useful cut-off value for HE4 as an ovarian tumor marker was established regardless of the menopausal status of the women, with improved clinical sensitivity, positive predictive value, and negative predictive value without lowering specificity. Currently, different cut-off values for HE4 in pre- and postmenopausal women are used globally. The cut-off value for CA125 was the same between pre- and postmenopausal women. Therefore, with the newly established cut-off value, HE4 can be used more conveniently in a non-specialized setting, especially when it is used in combination with CA125.

Assessment of exercise-induced stress via automated measurement of salivary cortisol concentrations and the testosterone-to-cortisol ratio: a preliminary study.

In this study, our aim was to validate whether the automated measurement of salivary testosterone and cortisol concentrations and the testosterone-to-cortisol (T/C) ratio, considering their individual circadian rhythms can be used to assess the stress response of male athletes to different exercise intensities accurately and effectively. We measured the salivary testosterone and cortisol concentrations and their respective serum concentrations that were collected from 20 male long-distance runners via passive drooling in the morning and evening for two consecutive days involving different exercise intensities. An electrochemiluminescence immunoassay was performed to evaluate the salivary testosterone and cortisol concentrations. The results showed a positive correlation between the salivary testosterone and cortisol concentrations and their respective serum concentrations. The participants were divided into two groups: with and without interval training. The interval training group showed a significantly higher rate of change in the salivary cortisol concentration and a significantly lower rate of change in the T/C ratio in the evening interval training on day 1 than lower-intensity running on day 2. Our results indicated that the salivary cortisol concentrations and the T/C ratio could distinguish between exercises at different intensities, which may be beneficial for detecting differences in stress responses among athletes.

Development of a novel drug information provision system for Kampo medicine using natural language processing technology.

BACKGROUND: Kampo medicine is widely used in Japan; however, most physicians and pharmacists have insufficient knowledge and experience in it. Although a chatbot-style system using machine learning and natural language processing has been used in some clinical settings and proven useful, the system developed specifically for the Japanese language using this method has not been validated by research. The purpose of this study is to develop a novel drug information provision system for Kampo medicines using a natural language classifier® (NLC®) based on IBM Watson. METHODS: The target Kampo formulas were 33 formulas listed in the 17th revision of the Japanese Pharmacopoeia. The information included in the system comes from the package inserts of Kampo medicines, Manuals for Management of Individual Serious Adverse Drug Reactions, and data on off-label usage. The system developed in this study classifies questions about the drug information of Kampo formulas input by natural language into preset questions and outputs preset answers for the questions. The system uses morphological analysis, synonym conversion by thesaurus, and NLC®. We fine-tuned the information registered into NLC® and increased the thesaurus. To validate the system, 900 validation questions were provided by six pharmacists who were classified into high or low levels of knowledge and experience of Kampo medicines and three pharmacy students. RESULTS: The precision, recall, and F-measure of the system performance were 0.986, 0.915, and 0.949, respectively. The results were stable even with differences in the amount of expertise of the question authors. CONCLUSIONS: We developed a system using natural language classification that can give appropriate answers to most of the validation questions.

Age-Related Sex Differences in Glucose Tolerance by 75 g Oral Glucose Tolerance Test in Japanese.

To elucidate the age-related sex difference in glucose tolerance, we conducted 75 g oral glucose tolerance tests in 1156 participants. Participants were divided into four groups, namely, young (22−29) males, young females, middle-aged (>50) males, and middle-aged females. According to the Japanese Clinical Practice Guideline for Diabetes 2019, the prevalence of normal glucose tolerance (NGT) was significantly lower in middle-aged than in young participants. The prevalence of high-normal fasting plasma glucose (FPG) was higher, and NGT was lower in young males (high-normal FPG 15.2%, NGT 82.0%) than young females (high-FPG 3.9%, NGT 94.3%). Combined glucose intolerance (CGI) was higher and NGT was lower in middle-aged males (CGI 10.2%, NGT 25.2%) than in middle-aged females (CGI 3.3%, NGT 39.8%). FPG and body mass index (BMI) were the lowest and Homeostatic model assessment beta cell function (HOMA-ß) was the highest in young females, followed by young males, middle-aged females, and middle-aged males. Multiple linear regression analysis revealed that BMI weakly correlated with HOMA-ß and Matsuda index in all subjects except young females. The superior glucose tolerance in females was apparent in young, but attenuated in middle-aged females. The differences are due to the higher insulin secretion potential and lower BMI in young females.

GPIHBP1 autoantibody is an independent risk factor for the recurrence of hypertriglyceridemia-induced acute pancreatitis.

BACKGROUND: GPIHBP1, a glycolipid-anchored protein of capillary endothelial cells, is a crucial partner for lipoprotein lipase (LPL) in plasma triglyceride metabolism. GPIHBP1 autoantibodies block LPL binding to GPIHBP1 and lead to severe hypertriglyceridemia (HTG) and HTG-induced acute pancreatitis (HTG-AP). We sought to define the incidence of GPIHBP1 autoantibodies in patients with HTG-AP. OBJECTIVE: We determined the incidence of GPIHBP1 autoantibody in HTG-AP patients, and compared the clinical features and long-term outcomes between GPIHBP1 autoantibody-positive and negative groups. METHODS: An enzyme-linked immunosorbent assay was used to screen for GPIHBP1 autoantibody in 116 HTG-AP patients hospitalized from Jan 1, 2015 to Aug 31, 2019. All patients were followed up for 24 months. The primary outcome was the recurrence rate of HTG-AP during the two-year follow-up period. The incidence of recurrent episodes was analyzed by the Kaplan-Meier method and multivariable Cox regression was used to identify risk factors. RESULTS: GPIHBP1 autoantibodies were present in 17 of 116 study patients (14.66%). The 2-year recurrence rate of HTG-AP was much higher in the GPIHBP1 autoantibody-positive group (35%, 6 in 17) than in the negative group (4%, 4 in 99). The multivariable Cox regression analysis showed that GPIHBP1 autoantibody was an independent risk factor for HTG-AP recurrence in two years. CONCLUSIONS: The presence of GPIHBP1 autoantibody is common in patients with HTG-AP, and is an independent risk factor for two-year recurrence of HTG-AP.

Differences in stress response between two altitudes assessed by salivary cortisol levels within circadian rhythms in long-distance runners.

There are conflicting reports regarding the efficacy of cortisol as a stress marker in altitude training due to the influence of the circadian rhythm. This study aimed to verify whether the automated measurement of salivary cortisol concentration via sequential sampling could detect the differences in exercise stress between two altitudes. We enrolled 12 elite female long-distance runners living near sea level. For the first higher-altitude camp, the runners lived at 1800 m and trained at 1700 m for 7 days. For the second lower-altitude camp, they lived at 1550 m and trained at 1300 m for 7 days. Their saliva was sequentially collected on the last 2 days during each camp which involved different intensity exercises in the morning and afternoon. The salivary cortisol concentrations were measured using electrochemiluminescence immunoassay. Before dinner, the basal salivary cortisol concentrations were significantly higher in the higher-altitude camp. The rate of change in the salivary cortisol concentration during the morning exercise was significantly higher in the higher-altitude camp than in lower-altitude camp (p = 0.028) despite the same exercise programs and intensities. Salivary cortisol level measurements during the athletes' circadian rhythms could detect the differences in acclimatization and exercise stress between two altitudes.

Electrostatic sheathing of lipoprotein lipase is essential for its movement across capillary endothelial cells.

GPIHBP1, an endothelial cell (EC) protein, captures lipoprotein lipase (LPL) within the interstitial spaces (where it is secreted by myocytes and adipocytes) and transports it across ECs to its site of action in the capillary lumen. GPIHBP1's 3-fingered LU domain is required for LPL binding, but the function of its acidic domain (AD) has remained unclear. We created mutant mice lacking the AD and found severe hypertriglyceridemia. As expected, the mutant GPIHBP1 retained the capacity to bind LPL. Unexpectedly, however, most of the GPIHBP1 and LPL in the mutant mice was located on the abluminal surface of ECs (explaining the hypertriglyceridemia). The GPIHBP1-bound LPL was trapped on the abluminal surface of ECs by electrostatic interactions between the large basic patch on the surface of LPL and negatively charged heparan sulfate proteoglycans (HSPGs) on the surface of ECs. GPIHBP1 trafficking across ECs in the mutant mice was normalized by disrupting LPL-HSPG electrostatic interactions with either heparin or an AD peptide. Thus, GPIHBP1's AD plays a crucial function in plasma triglyceride metabolism; it sheathes LPL's basic patch on the abluminal surface of ECs, thereby preventing LPL-HSPG interactions and freeing GPIHBP1-LPL complexes to move across ECs to the capillary lumen.

Serological Screening of Immunoglobulin G against SARS-CoV-2 Nucleocapsid and Spike Protein before and after Two Vaccine Doses among Healthcare Workers in Japan.

This study sought to evaluate the effects of two vaccine doses and the extent of SARS-CoV-2 infection among healthcare workers. We measured immunoglobulin G antibody titers against SARS-CoV-2 nucleocapsid and spike protein among healthcare workers at Gunma University Hospital. In March 2021, prior to BNT-162b2 vaccination, two of 771 participants were seropositive for nucleocapsid and spike protein, whereas 768 were seronegative. The remaining one participant was seropositive for nucleocapsid protein but seronegative for spike protein. A total of 769 participants were seropositive for spike protein after two vaccination doses. The two seropositive participants prior to vaccination showed the highest antibody titers after the second vaccination. They were probably infected with SARS-CoV-2 without clinical symptoms before March 2021. Four weeks after the second vaccination, a younger age was associated with higher antibody titers against SARS-CoV-2 spike protein. Thirty-two weeks after the second vaccination, blood samples were collected from 342 of 769 participants. Antibody titers at 32 weeks after the second vaccination significantly decreased compared with those at 4 weeks after the second vaccination among all age groups. The rate of decrease in antibody titers between 4 and 32 weeks after the second vaccination was greater in the female participants. No sex differences were observed in the antibody titers within each age group. BNT-162b2 vaccination thus induced seroconversion in an age-dependent manner. Serological screening could further establish the likelihood of subclinical SARS-CoV-2 infection.

Association Between Insulin Resistance and Cardinal Rheological Parameters in Young Healthy Japanese Individuals During 75g Oral Glucose Tolerance Test.

BACKGROUND: Insulin resistance is a well-known predictor and risk factor for type 2 diabetes mellitus (T2DM). Higher hematocrit induced by higher insulin resistance affects blood rheology. OBJECTIVE: This study intended to reveal the association between indices of insulin resistance and hemorheological parameters during a 75 g oral glucose tolerance test (75-g OGTT). METHODS: A total of 575 healthy young Japanese participants took 75-g OGTT. We then analyzed the association between insulin resistance indices and hematological parameters. RESULTS: The Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was significantly correlated with hematocrit (Ht), hemoglobin (Hb), red blood cell (RBC), white blood cell (WBC), platelet count, lipid parameters and body mass index (BMI). The Matsuda index was negatively correlated with RBC count, WBC count, platelet count, total cholesterol (TC), low-density lipoprotein- cholesterol (LDL-C), triglyceride (TG), and positively correlated with high-density lipoprotein- cholesterol (HDL-C). The disposition index was negatively correlated with Hb, RBC count, LDL-C and BMI, and positively correlated with HDL-C. The Homeostasis Model Assessment of beta cell (HOMA-ß) was positively correlated with WBC count, platelet count, TC, LDL-C and TG. The insulinogenic index was positively correlated with WBC count, platelet count and TC. Multiple regression analysis revealed that HOMA-IR was independently associated with TG, and the Matsuda index was independently associated with TG, WBC count, and platelet count. The insulinogenic index was independently associated with WBC count. CONCLUSION: Cardinal rheological parameters reflected insulin resistance and release even in young healthy Japanese individuals within the physiological range of glycemic control.

Konjac Glucomannan Attenuated Triglyceride Metabolism during Rice Gruel Tolerance Test.

In a recent study, we showed that konjac glucomannan (KGM) inhibits rice gruel-induced postprandial increases in plasma glucose and insulin levels. To extend this research, we investigated the effects of KGM addition to rice gruel on pre- and postprandial concentrations of circulating lipoprotein lipase (LPL), glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), hepatic triglyceride lipase (HTGL), free fatty acids (FFA), and triglycerides (TG). A total of 13 Japanese men, without diabetes, dyslipidemia, or gastrointestinal diseases, interchangeably ingested rice gruel containing no KGM (0%G), rice gruel supplemented with 0.4% KGM (0.4%G), and rice gruel supplemented with 0.8% KGM (0.8%G), every Sunday for 3 weeks. Blood samples were obtained at baseline and at 30, 60, and 120 min after ingestion to measure the abovementioned lipid parameters. Lipid parameters showed small, but significant, changes. Significant reductions were found in circulating FFA levels among all participants. Circulating TG levels significantly declined at 30 min and then remained nearly constant in the 0.8%G group but exhibited no significant difference in the 0%G and 0.4%G groups. Although circulating levels of LPL and GPIHBP1 significantly decreased in the 0%G and 0.4%G groups, they increased at 120 min in the 0.8%G group. Participants in the 0%G and 0.4%G groups showed significant decreases in circulating HTGL levels, which was not observed in the 0.8%G group. Our results demonstrate the novel pleiotropic effects of KGM. Supplementation of rice gruel with KGM powder led to TG reduction accompanied by LPL and GPIHBP1 elevation and HTGL stabilization, thereby attenuating TG metabolism.

Significance of serum branched-chain amino acid to tyrosine ratio measurement in athletes with high skeletal muscle mass.

BACKGROUND: Few nutritional markers reflect the hypermetabolic state of athletes with high levels of skeletal muscle. Although branched-chain amino acids (BCAA) play crucial roles in protein metabolism in skeletal muscle, the relationship between skeletal muscle mass and amino acid imbalances caused by the metabolism of BCAA and aromatic amino acids remains unclear. The aim of this study is to test the hypothesis that athletes with high levels of skeletal muscle mass have plasma amino acid imbalances, assessed by serum BCAA to tyrosine ratio (BTR) which can be measured conveniently. METHODS: The study enrolled 111 young Japanese men: 70 wrestling athletes and 41 controls. None of them were under any medications, extreme dietary restrictions or intense exercise regimens. Each participant's body composition, serum concentrations of albumin and rapid turnover proteins including transthyretin and transferrin, BTR, and thyroid function were assessed. RESULTS: Compared to the controls, the athletes had significantly higher skeletal muscle index (SMI) (p < 0.001), and lower serum albumin concentration (p < 0.001) and BTR (p < 0.001). Kruskal-Wallis tests showed that serum albumin concentration and BTR were significantly lower in the participants with higher SMI. Serum albumin concentration and BTR were inversely correlated with SMI by multiple regression analysis (logarithmic albumin, ß = - 0.358, p < 0.001; BTR, ß = - 0.299, p = 0.001). SMI was inversely and transthyretin was positively correlated with serum albumin (SMI, ß = - 0.554, p < 0.001; transthyretin, ß = 0.379, p < 0.001). Serum concentration of free 3,5,3'-triiodothyronine (FT3) was inversely correlated with BTR, and, along with SMI and albumin, was independent predictor of BTR (SMI, ß = - 0.321, p < 0.001; FT3, ß = - 0.253, p = 0.001; logarithmic albumin, ß = 0.261, p = 0.003). However, FT3 was not correlated with SMI or serum albumin. Serum concentrations of rapid turnover proteins were not correlated with BTR. CONCLUSIONS: Increased skeletal muscle mass enhances the circulating amino acid imbalances, and is independently facilitated by thyroid hormones. Serum BTR may be a useful biomarker to assess the hypermetabolic state of wrestling athletes with high levels of skeletal muscle.

Association between high normal-range thyrotropin concentration and carotid intima-media thickness in euthyroid premenopausal, perimenopausal and postmenopausal women.

OBJECTIVE: There are currently no established cutoff levels for thyrotropin (TSH) within the reference intervals associated with carotid atherosclerosis to prevent the onset of cardiovascular diseases. The present study aimed to determine the TSH cutoff level associated with carotid maximum intima-media thickness (max IMT) in euthyroid premenopausal, perimenopausal and postmenopausal women. STUDY DESIGN: We conducted a cross-sectional study of 468 euthyroid women who had not been treated for or diagnosed with cardiovascular diseases and/or metabolic disorders among 1221 Japanese women who participated in a comprehensive medical examination at the Hidaka Hospital, Japan. Participants' weight, blood pressure, plasma glucose, serum lipoprotein, free thyroxine and TSH were measured and an interview about menstruation was conducted. Carotid ultrasonography was performed to determine max IMT. RESULTS: Max IMT significantly increased stepwise as menopausal status progressed (p < 0.001). Serum TSH levels were significantly higher in participants with carotid plaques, defined as max IMT ≥1.1 mm (p = 0.038), and were independently associated with the presence of carotid plaque using multivariate logistic regression analysis (ß =1.218, p = 0.036). In postmenopausal women, significantly higher carotid max IMT values were observed in women with serum TSH ≥2.5 µIU/mL compared with women with concentrations <2.5 µIU/mL (p = 0.018) without elevated total cholesterol and low-density lipoprotein cholesterol concentrations. These differences were not observed in premenopausal women. CONCLUSIONS: Laboratory finding of serum TSH concentration ≥2.5 µIU/mL may be useful to assess risk of atherosclerosis, especially in postmenopausal women.

Simultaneous capillary electrophoresis of anions and cations in a single injection using an anion exchanger-modified capillary for determination of salivary ions in combination with statistical analyses.

This paper describes the simultaneous capillary electrophoresis (CE) of anions and cations using an anion exchange-modified capillary, which was prepared by chemical coating with a cationic silylating reagent, and its application to saliva analysis. The CE method provides high-throughput (5 min for a single sample injection) analysis by generating a high-velocity electroosmotic flow at pH 3.0-3.5. The detection limits at a signal-to-noise ratio of 3 ranged from 1.2 to 18 µM for anions and 1.0 to 2.7 µM for cations. The relative standard deviations for the migration times and peak areas of analytes (n = 4) ranged from 0.05% to 0.40% and 0.94% to 4.7%, respectively. The CE system was used to analyze 11 common ions in saliva samples collected from long-distance runners and sedentary university students before and after running for a set distance or a set time. Interestingly, the SCN- concentrations decreased in the saliva samples of all 14 athletes and 16 sedentary students after running. Furthermore, when the concentrations of the analyzed ions were compared with that of cortisol as a typical stress marker by multiple regression analysis, SCN- and NO3- in saliva samples from the two subject groups strongly correlated with cortisol levels, as determined by an electrochemiluminescence immunoassay. This study improves our knowledge of both the analytical methodology for CE and statistical methods for identifying common ions that could be used as physical stress markers.

Assessment of exercise-induced stress by automated measurement of salivary cortisol concentrations within the circadian rhythm in Japanese female long-distance runners.

BACKGROUND: Overtraining syndrome, caused by prolonged excessive stress, results in reduced performance and cortisol responsiveness in athletes. It is necessary to collect saliva samples sequentially within circadian rhythm for assessing exercise stress by measuring cortisol concentrations, and automated cortisol measurements using electrochemiluminescence immunoassay (ECLIA) may be useful for measuring a large number of saliva samples. In this study, we evaluated the appropriate use of cortisol-based exercise stress assessment within the circadian rhythm, which may diagnose and prevent overtraining syndrome in athletes. METHODS: We collected saliva and sera from 54 healthy participants and analyzed the correlation between salivary cortisol concentrations measured by ECLIA and enzyme-linked immunosorbent assay (ELISA) or serum cortisol analysis. We also collected saliva continuously from 12 female long-distance runners on 2 consecutive days involving different intensities and types of exercise early in the morning and in the afternoon and measured salivary cortisol concentrations using ECLIA. Each exercise intensity of runners was measured by running velocities, Borg Scale score, and rate of change in the pulse rate by exercise. RESULTS: ECLIA-based salivary cortisol concentrations correlated positively with those detected by ELISA (ρ = 0.924, p < 0.001) and serum cortisol (ρ = 0.591, p = 0.001). In long-distance runners, circadian rhythm of salivary cortisol, including the peak after waking and the decrease promptly thereafter, were detected on both days by continuous saliva sampling. The rates of change in salivary cortisol concentrations were significantly lower after an early morning exercise than after an afternoon exercise on both days (day 1, p = 0.002, and day 2, p = 0.003). In the early morning exercise, the rate of change in salivary cortisol concentration was significantly higher on day 1 than on day 2 (p = 0.034), similar to a significant difference in running velocities (p = 0.001). CONCLUSIONS: Our results suggest that automated ECLIA-based salivary cortisol measurements are able to detect the athletes' circadian rhythm and compare the exercise stress intensities at the same times on different days, even in the early morning, possibly leading to the prevention of overtraining syndrome.