Elevated level of urinary tellurium is a potential risk for increase of blood pressure in humans and mice

BACKGROUND

People worldwide are routinely exposed to tellurium mainly via dietary ingestion. There has been no study to clarify the contribution of tellurium to blood pressure in humans or animals.

METHODS

In this cross-sectional study conducted in a general population of 2592 residents in Japan, the associations of urinary tellurium levels with blood pressure and prevalence of hypertension were investigated. The potential sources of tellurium were also investigated. An interventional study in mice confirmed the effect of tellurium exposure on blood pressure.

RESULTS

Linear and logistic regression analyses with consideration of confounders including urinary sodium-potassium ratio showed significant positive associations of urinary tellurium level with prevalence of hypertension and blood pressure. Cereals/beans and vegetables/fruits were determined to be potential dietary sources of tellurium exposure. Intermediary analysis suggested that increased intake of cereals/beans, but not that of vegetables/fruits, is positively associated with the tellurium-mediated risk of hypertension. Correspondingly, the mouse study showed that exposure to a putative human-equivalent dose of tellurium via drinking water increased blood pressure with an elevated level of urinary tellurium. The temporally increased blood pressure was decreased to the normal level by a break of tellurium exposure with a reduced level of urinary tellurium.

CONCLUSIONS

The interdisciplinary approach provided the first evidence that tellurium exposure is a potential risk for increase of blood pressure. Since the human urinary tellurium level in this study is comparable with the levels in general populations in other Asian and European countries in previous studies, exposure to tellurium may be a latent universal risk for hypertension.

Elevated arsenic level in fasting serum via ingestion of fish meat increased the risk of hypertension in humans and mice

Aims

There has been a shortage of human studies to elucidate the association between serum arsenic levels and the prevalence of hypertension. This study multidirectionally investigated associations among arsenic exposure, dietary ingestion, and the risk of hypertension by combined human epidemiological and mouse experimental studies.

Methods and results

This study focused on the total arsenic level in fasting serum, a biomarker of arsenic exposure. Associations among ingestion frequencies of 54 diet items of Japanese food separated into six categories, total arsenic level in fasting serum, and the prevalence of hypertension were investigated in 2709 general people in Japan. Logistic regression analysis demonstrated a dose-dependent association between serum arsenic level and hypertension and a positive association between the ingestion of fish meat and hypertension. Further analysis showed that the latter association was fully mediated by increased fasting serum arsenic levels in humans. Similarly, oral exposure to the putative human-equivalent dose of arsenic species mixture with the same ratios in a common fish meat in Japan increased systolic blood pressure and arsenic levels in fasting serum in mice.

Conclusion

This interdisciplinary approach suggests that fish-meat ingestion is a potential risk factor for arsenic-mediated hypertension. Because the increased consumption of fish meat is a recent global trend, health risks of the increased ingestion of arsenic via fish meat should be further investigated.

[Overview of occupational diseases induced by trichloroethylene and associated basic research]

OBJECTIVE

To provide an overview of the pathogenesis of pneumatosis cystoides intestinalis (PCI) and hypersensitivity syndrome (HS) caused by trichloroethylene (TCE) and the basic research into their toxicity.

SUBJECTS AND METHODS

We reviewed previously published research articles.

RESULTS

PCI clustered in Japan in the 1980s is a rare disease characterized by cyst-like distention of gas in the intestinal wall, which can be secondary or primary. No TCE users were found in the former group, whereas approximately 71% of the latter group were TCE users, suggesting the involvement of TCE exposure in primary PCI. However, the pathogenesis was unclear. TCE is metabolized by the drug-metabolizing enzyme CYP2E1, and intermediate immunocomplexes with CYP2E1 may be involved in hepatotoxicity. HS clustered in the southern part of China since early 2000 is a systemic skin-liver disorder involving anti-CYP2E1 autoantibodies and HLA-B*13:01 polymorphisms, with elevated cytokines and reactivation of Human Herpesvirus 6.

DISCUSSION AND CONCLUSION

PCI and HS, occupational diseases caused by TCE, were clustered in Japan and southern China, respectively. HS was mediated by immune system disorders and genetic polymorphisms, whereas the intervention for PCI remained unknown.

Relationship Between Fasting Blood Glucose Levels in Middle Age and Cognitive Function in Later Life: The Aichi Workers' Cohort Study

BACKGROUND

There is limited evidence regarding the relationship between Diabetes mellitus (DM) in middle age and mild cognitive impairment after a follow-up. Therefore, we investigated the relationship between fasting blood glucose (FBG) levels in middle age and cognitive function assessed using the Japanese version of the Montreal Cognitive Assessment (MoCA-J) in later life, following over 15 years of follow-up in the Aichi Workers' Cohort Study in Japan.

METHODS

Participants were 253 former local government employees aged 60-79 years in 2018 who participated in a baseline survey conducted in 2002. Using baseline FBG levels and self-reported history, participants were classified into the normal, impaired fasting glucose (IFG) and, and DM groups. Total MoCA-J score ranges from 0 to 30, and cognitive impairment was defined as MoCA-J score ≤25 in this study. A general linear model was used to estimate the mean MoCA-J scores in the FBG groups, adjusted for age, sex, educational year, smoking status, alcohol consumption, physical activity, body mass index, systolic blood pressure, total cholesterol, and estimated glomerular filtration rate.

RESULTS

The mean MoCA-J score in the total population was 25.0, and the prevalence of MoCA-J score ≤25 was 49.0%. Multivariable-adjusted total MoCA-J scores were 25.2, 24.8, and 23.4 in the normal, IFG, and DM groups, respectively. The odds ratio of MoCA-J score ≤25 in the DM group was 3.29.

CONCLUSION

FBG level in middle age was negatively associated with total MoCA-J scores assessed later in life, independent of confounding variables.

Effects of Arterial Stiffness on Cerebral WM Integrity in Older Adults: A Neurite Orientation Dispersion and Density Imaging and Magnetization Transfer Saturation Imaging Study

BACKGROUND AND PURPOSE

Arterial stiffness is reported to be able to cause axonal demyelination or degeneration. The present study aimed to use advanced MR imaging techniques to examine the effect of arterial stiffness on the WM microstructure among older adults.

MATERIALS AND METHODS

Arterial stiffness was measured using the cardio-ankle vascular elasticity index (CAVI). The high-CAVI (mean CAVI ≥ 9 points) and the low-CAVI groups (mean CAVI < 9 points) were created. The neuronal fiber integrity of the WM was evaluated by neurite orientation dispersion and density imaging and magnetization transfer saturation imaging. Tract-Based Spatial Statistics and the tracts-of-interest analysis were performed. Specific WM regions (corpus callosum, internal capsule, anterior thalamic radiation, corona radiata, superior longitudinal fasciculus, forceps minor, and inferior fronto-occipital fasciculus) were selected in the tracts-of-interest analysis.

RESULTS

In Tract-Based Spatial Statistics, the high-CAVI group showed a significantly lower myelin volume fraction value in the broad WM and significantly higher radial diffusivity and isotropic volume fraction values in the corpus callosum, forceps minor, inferior fronto-occipital fasciculus, internal capsule, corona radiata, and anterior thalamic radiation than the low-CAVI group. In tracts-of-interest analysis using multivariate linear regression, significant associations were found between the mean CAVI and radial diffusivity in the anterior thalamic radiation and the corona radiata; isotropic volume fraction in the anterior thalamic radiation and the corona radiata; and myelin volume fraction in the superior longitudinal fasciculus (P < .05). Additionally, partial correlation coefficients were observed for the significant associations of executive function with radial diffusivity and myelin volume fraction (P < .05).

CONCLUSIONS

Arterial stiffness could be associated with demyelination rather than axonal degeneration.

Increased serum anti-CYP2E1 IgG autoantibody levels may be involved in the pathogenesis of occupational trichloroethylene hypersensitivity syndrome: a case-control study

Occupational exposure to trichloroethylene (TCE) causes a systemic skin disorder with hepatitis known as TCE hypersensitivity syndrome (TCE-HS). Human Leukocyte Antigen (HLA)-B*13:01 is its susceptibility factor; however, the immunological pathogenesis of TCE-HS remains unknown. We herein examined the hypothesis that autoantibodies to CYP2E1 are primarily involved in TCE-HS. A case–control study of 80 TCE-HS patients, 186 TCE-tolerant controls (TCE-TC), and 71 TCE-nonexposed controls (TCE-nonEC) was conducted to measure their serum anti-CYP2E1 antibody (IgG) levels. The effects of TCE exposure indices, such as 8-h time-weighted-average (TWA) airborne concentrations, urinary metabolite concentrations, and TCE usage duration; sex; smoking and drinking habits; and alanine aminotransferase (ALT) levels on the antibody levels were also analyzed in the two control groups. There were significant differences in anti-CYP2E1 antibody levels among the three groups: TCE-TC > TCE-HS patients > TCE-nonEC. Antibody levels were not different between HLA-B*13:01 carriers and noncarriers in TCE-HS patients and TCE-TC. The serum CYP2E1 measurement suggested increased immunocomplex levels only in patients with TCE-HS. Multiple regression analysis for the two control groups showed that the antibody levels were significantly higher by the TCE exposure. Women had higher antibody levels than men; however, smoking, drinking, and ALT levels did not affect the anti-CYP2E1 antibody levels. Anti-CYP2E1 antibodies were elevated at concentrations lower than the TWA concentration of 2.5 ppm for TCE exposure. Since HLA-B*13:01 polymorphism was not involved in the autoantibody levels, the possible mechanism underlying the pathogenesis of TCE-HS is that TCE exposure induces anti-CYP2E1 autoantibody production, and HLA-B*13:01 is involved in the development of TCE-HS.

One-Pot Extraction and Quantification Method for Bile Acids in the Rat Liver by Capillary Liquid Chromatography Tandem Mass Spectrometry

We developed a highly sensitive method for quantifying 21 bile acids (BAs) in the rat liver by capillary liquid chromatography tandem mass spectrometry (cLC/MS/MS) with one-pot extraction. High recovery rates were obtained for the one-pot methods with either methanol (MeOH) extraction or MeOH/acetonitrile (ACN) (1:1, v/v) mixture extraction; the results obtained for the MeOH/ACN mixture solution were better than the results obtained for MeOH. Thus, we determined that the one-pot method with MeOH/ACN was the most suitable method for the efficient extraction of BAs in the liver. Targeted BAs were well separated by cLC with gradient elution using ammonium acetate (NH₄OAc)-MeOH mobile phases. Method validation proved that the intra-day and inter-day accuracies and precisions were primarily less than ±20 and 20% relative standard deviation, respectively. Also, the limit of detection (LOD) and the limit of quantitation (LOQ) were 0.9-10 and 2.3-27 ng/g liver, which proves the high sensitivity of the method. Finally, we quantitated 21 BA concentrations in the liver samples of normal and nonalcoholic steatohepatitis (NASH) rats, both of which were derived from stroke-prone spontaneously hypertensive five (SHRSP5) /Dmcr rat. The hepatic BA profiles were found to be substantially different between the normal and NASH groups; the two groups were clearly separated along the first component axis in the score plots of the principal component analysis. In particular, 10 BAs (β-muricholic acid (MCA), glyco (G-) cholic acid (CA), G-chenodeoxycholic acid (CDCA), tauro (T-) CA, T-CDCA, T-ursodeoxycholic acid (UDCA), T-lithocholic acid (LCA), T-hiodeoxycholic acid (HDCA), T-α-MCA, and T-β-MCA) were significantly different between the two groups using Welch's t-test with the false discovery rate correction method, demonstrating BA disruption in the NASH model rat. In conclusion, this method was able to quantify 21 BAs in the rat liver and will evaluate the hepatic BA pathophysiology of rat disease models.

The antihypertensive agent hydralazine reduced extracellular matrix synthesis and liver fibrosis in nonalcoholic steatohepatitis exacerbated by hypertension

Hypertension is an important risk factor for nonalcoholic steatohepatitis. We have previously demonstrated that hypertensive rats fed a high fat and cholesterol (HFC) diet incurred a more severe hepatic inflammatory response and fibrosis. Here we investigated the role of hypertension in NASH by comparing HFC-induced hepatic fibrogenesis between spontaneously hypertensive rats (SHRs) and their normotensive Wistar Kyoto counterpart. Compared to the counterpart, the HFC diet led to stronger aggregation of CD68-positive macrophages in SHRs. HFC feeding also resulted in significantly higher upregulation of the fibrosis-related gene alpha-smooth muscle actin in SHR. The HFC diet induced higher overexpression of serum tissue inhibitor of metalloproteinase-1 (TIMP1) and greater suppression of matrix metalloproteinase-2 (MMP2):TIMP1, MMP8:TIMP1, and MMP9:TIMP1 ratios, as a proxy of the activities of these MMPs in SHR. Administration of the antihypertensive agent hydralazine to SHRs significantly ameliorated HFC-induced liver fibrosis; it suppressed the aggregation of CD68-positive macrophages and the upregulation of platelet-derived growth factor receptor beta, and collagen, type 1, alpha-1 chain. In conclusion, a hypertensive environment exacerbated the hepatic fibrogenetic effects of the HFC diet; while the effects were partially reversed by the antihypertensive agent hydralazine. Our data suggest that antihypertensive drugs hold promise for treating NASH exacerbated by hypertension.

Increased risk of occupational trichloroethylene hypersensitivity syndrome at exposure levels higher than 15 mg/L of urinary trichloroacetic acid, regardless of whether the patients had the HLA-B*13:01 allele

Occupational trichloroethylene (TCE) exposure can cause hypersensitivity syndrome (TCE-HS). The human leukocyte antigen (HLA)-B*13:01 is reportedly an important allele involved in TCE-HS onset. However, the threshold exposure level causing TCE-HS in relation to HLA-B*13:01 remains unknown. We conducted a case-control study comprising 37 TCE-HS patients and 97 age- and sex-matched TCE-tolerant controls from the Han Chinese population. Urine and blood of patients were collected on the first day of hospitalization, and those of controls were collected at the end of their shifts. Urinary trichloroacetic acid (TCA) was measured as an exposure marker, and end-of-shift levels in the patients were estimated using the biological half-life of 83.7 h. HLA-B genotype was identified using DNA from blood. Crude odds ratios (ORs) for TCE-HS in the groups with urinary TCA concentration >15 mg/L to ≤50 mg/L and of >50 mg/L were 21.9 [95% confidence interval (CI) 4.2-114.1] and 27.6 (6.1-125.8), respectively, when the group with urinary TCA ≤15 mg/L was used as a reference. The frequency of HLA-B*13:01, the most common allele in the patients, was 62.2% (23/37), which was significantly higher than 17.5% (17/97) in the TCE-tolerant controls, with a crude OR of 8.4 (3.1-22.6). The mutually-adjusted ORs for urinary TCA >15 to ≤50 mg/L, >50 mg/L, and for HLA-B*13:01 were 33.4 (4.1-270.8), 34.0 (5.3-217.1), and 11.0 (2.4-50.7), respectively. In conclusion, reduction of TCE exposure to ≤15 mg/L is required for TCE-HS prevention because urinary TCA concentration >15 mg/L showed increased risk of TCE-HS, regardless of whether the patients had the HLA-B*13:01 allele.

Positive Association of Physical Activity with Both Objective and Perceived Measures of the Neighborhood Environment among Older Adults: The Aichi Workers' Cohort Study

We examined the association between objective and perceived neighborhood characteristics and self-reported leisure-time physical activity (PA) in older Japanese residents living in areas ranging from metropolitan to rural in 2016. Objective measures used were walkability and the numbers of parks/green spaces and sports facilities within 500 or 1000 m of subjects’ homes, calculated using geographic information systems. Subjective measures were the subjects’ perceptions of their neighborhoods, assessed using a structured questionnaire. All variables were divided into three groups, and the lowest tertile was used as the reference. We assessed the location and frequency of strolling or brisk walking, moderate-intensity PA, and vigorous-intensity PA (sports) using a self-reported questionnaire and defined as performing a certain type of PA 3–4 times/week as a habit. Living in a neighborhood in the highest tertile for walkability and number of parks/green spaces as well as perception of having good access to recreational facilities, observing others exercising and the presence of walkable sidewalks was associated with walking and sports habits (multivariable odds ratios (ORs): 1.33–2.46, all p < 0.05). Interestingly, objective measures of PA-friendly environmental features were inversely associated with moderate-intensity PA habits, potentially because moderate-intensity PA consisted predominantly of gardening. In conclusion, living in an environment supportive of PA, whether objectively or subjectively measured, is related to leisure-time PA habits among older Japanese adults.

Trichloroethylene and trichloroethanol induce skin sensitization with focal hepatic necrosis in guinea pigs

OBJECTIVES

Occupational exposure to trichloroethylene (TCE) induces trichloroethylene hypersensitivity syndrome (TCEHS), which causes hypersensitivity dermatitis and hepatitis. However, whether TCE itself or its two metabolites, trichloroethanol (TCEOH) and trichloroacetic acid (TCA), are involved in TCEHS remains unclear. Therefore, in this study we explored the allergens causing TCEHS and characterized TCEHS-related liver injury in guinea pigs.

METHOD

The guinea pig maximization test was performed using TCE, TCEOH, and TCA as candidate allergens. Skin inflammation was scored, and liver function and histopathological changes were evaluated by biochemical tests and hematoxylin and eosin staining, respectively.

RESULTS

The sensitization rates for TCE, TCEOH, and TCA were 90.0%, 50.0%, and 0.0%, respectively. In the TCE and TCEOH experimental groups, the skin showed varying degrees of erythema with eosinophil granulocyte infiltration in the dermis. Additionally, serum alanine aminotransferase and γ-glutamyl transpeptidase levels increased significantly, and histological analysis revealed focal hepatocellular necrosis with inflammatory cell infiltration in the liver.

CONCLUSIONS

TCE is the main cause of allergy and TCEOH is a secondary factor for allergy in guinea pigs. TCE and TCEOH can cause immune-mediated skin sensitization complicated by focal hepatic necrosis.

Decrescent intensity training concurrently improves maximal anaerobic power, maximal accumulated oxygen deficit, and maximal oxygen uptake

This study aimed to investigate the effects of a gradually decreasing intensity training from that corresponding to maximal anaerobic power (MAnP) to that of near maximal oxygen uptake ([Formula: see text]) (decrescent intensity training) on MAnP, maximal accumulated oxygen deficit (MAOD), and [Formula: see text] in untrained young men. Seventeen untrained young men were randomly divided into either a training (TR; n = 9) group or a control (CON; n = 8) group. The TR group performed the decrescent intensity training, whereas the CON group did not perform any exercises. The mean training time per session throughout the training period was 275 ± 135 s. There was a Group × Time interaction for both absolute and relative (p < 0.01) values of [Formula: see text], MAOD, and MAnP. The TR group had significantly increased values for all variables after the 8-week training program, and the relative values of all variables were significantly higher in the TR group than in the CON group. Muscle thicknesses in the anterior and posterior aspects of the thigh and maximal isokinetic knee extension and flexion strengths improved only in the TR group (p < 0.05). A single-exercise training with gradually decreasing intensity from that corresponding to the MAnP to that of approximately 100% [Formula: see text] improves MAnP, MAOD, and [Formula: see text] concurrently, despite the short training time per session.

Energy expenditure, recovery oxygen consumption, and substrate oxidation during and after body weight resistance exercise with slow movement compared to treadmill walking

The benefit of body weight resistance exercise with slow movement (BWRE-slow) for muscle function is well-documented, but not for energy metabolism. We aimed to examine physiological responses [e.g., energy expenditure (EE), respiratory exchange ratio (RER), and blood lactate (La)] during and after BWRE-slow compared to EE-matched treadmill walking (TW). Eight healthy young men (23.4 ± 1.8 years old, 171.2 ± 6.2 cm, 63.0 ± 4.8 kg) performed squat, push-up, lunge, heel-raise, hip-lift, and crunch exercises with BWRE-slow modality. Both the concentric and eccentric phases were set to 3 s. A total of three sets (10 repetitions) with 30 s rest between sets were performed for each exercise (26.5 min). On another day, subjects walked on a treadmill for 26.5 min during which EE during exercise was matched to that of BWRE-slow with the researcher controlling the treadmill speed manually. The time course changes of EE and RER were measured. The EE during exercise for BWRE-slow (92.6 ± 16.0 kcal for 26.5 min) was not significantly different from the EE during exercise for TW (95.5 ± 14.1 kcal, p = 0.36). BWRE-slow elicited greater recovery EE (40.55 ± 3.88 kcal for 30 min) than TW (37.61 ± 3.19 kcal, p = 0.029). RER was significantly higher in BWRE-slow during and 0-5 min after exercise, but became significantly lower during 25-30 min after exercise, suggesting greater lipid oxidation was induced about 30 min after exercise in BWRE-slow compared to TW. We also indicated that BWRE-slow has 3.1 metabolic equivalents in average, which is categorized as moderate-intensity physical activity.

In utero exposure to di(2-ethylhexyl)phthalate suppresses blood glucose and leptin levels in the offspring of wild-type mice

Exposure of pregnant mice to di(2-ethylhexyl)phthalate (DEHP) induces maternal lipid malnutrition and decreases the number of live fetuses/pups. In this study, we aimed to clarify the relationship between maternal lipid malnutrition and the nutritional status of the neonatal, lactational, and adult offspring, as well as the role of peroxisome proliferator-activated receptor α (PPARα) in these relationships. Sv/129 wild-type (mPPARA), Ppara-null, and PPARα-humanized (hPPARA) mice were fed diets containing 0, 0.01, 0.05, or 0.1% DEHP in utero and/or during the lactational stage. The male offspring were killed on postnatal day 2 or 21, or after 11 weeks. Exposure to either 0.05% or 0.1% DEHP during both the in utero and lactational periods decreased serum glucose concentrations in 2-day-old mPPARA offspring. These dosages also decreased both serum and plasma leptin levels in both 2- and 21-day-old mPPARA offspring. In contrast, exposure to DEHP only during the lactational period did not decrease leptin levels, suggesting the importance of in utero exposure to DEHP. Exposure to 0.05% DEHP during the in utero and lactational periods also increased food consumption after weaning in both mPPARA and hPPARA mice; this was not observed in Ppara-null offspring. In conclusion, in utero exposure to DEHP induces neonatal serum glucose malnutrition via PPARα. DEHP also decreases serum and plasma leptin concentrations in offspring during the neonatal and weaning periods, in association with PPARα, which presumably results in increased of food consumption after weaning.

Smoking results in accumulation of ectopic fat in the liver

OBJECTIVE

An association between smoking and nonalcoholic fatty liver disease has been reported. However, objective quantification of intrahepatic fat via magnetic resonance spectroscopy (MRS) in relation to smoking has rarely been performed in previous studies. Moreover, the possible pathways via which smoking could induce ectopic fat accumulation have not yet been addressed. The current study aimed to examine the association between smoking status and intrahepatic fat quantity and explore the possible mediating effects of triglycerides (TG) and adiponectin.

SUBJECTS AND METHODS

Magnetic resonance imager (MRI) spectra were analyzed to quantify intrahepatic fat in 45 men who were on average 62.3 years of age. Smoking status and alcohol intake were self-reported. Accelerometers were used to record daily total physical activity. Fasting blood TG and adiponectin levels were measured enzymatically. Differences in mean intrahepatic fat values according to smoking status were assessed using analysis of covariance.

RESULTS

A stepwise increase in mean intrahepatic fat was observed between never, former, and current smokers, respectively, independent of age, physical activity, alcohol intake, and body mass index (BMI) (P=0.005). Adjustment for TG and adiponectin significantly attenuated this association (P=0.074).

CONCLUSION

Current smoking was significantly associated with increased intrahepatic fat, which may be a result of adipocyte dysfunction, manifested as high circulating TG concentrations and low adiponectin levels.

Regulation of Perfusion Pressure during Cardiopulmonary bypass using Sevoflurane

In hypothermic cardiopulmonary bypass (CPB), various vasodilators are used to control the perfusion pressure. These agents, however, often decrease the pressure excessively, and the low perfusion pressure may persist until the end of CPB. In this study we evaluate the safety and characteristics of the regulation of perfusion pressure during CPB using a volatile anesthetic, sevoflurane which has an extremely low partition coefficient. Twenty adult patients who underwent cardiac surgery were studied. Sevoflurane was applied by a vaporizer inserted into the oxygenator gas supply line. Pump flows were fixed at 2.4 L/min/m2 during the hypothermic period. Sevoflurane concentration was adjusted to keep mean arterial pressure (MAP) between 40 and 70 mmHg during CPB. Hemodynamic and metabolic parameters were measured and compared to the group we previously treated with chlorpromazine. In all cases, MAP could be maintained adequately. In the sevoflurane group, systemic vascular resistance indices (SVRI) during the rewarming period and at the end of CPB were higher, and doses of norepinephrine needed at the end of CPB were significantly lower than in the chlorpromazine group. The regulation of perfusion pressure during CPB using sevoflurane was safe and could easily maintain adequate SVRI.

Bile acid detoxifying enzymes limit susceptibility to liver fibrosis in female SHRSP5/Dmcr rats fed with a high-fat-cholesterol diet

During middle age, women are less susceptible to nonalcoholic steatohepatitis (NASH) than men. Thus, we investigated the underlying molecular mechanisms behind these sexual differences using an established rat model of NASH. Mature female and male stroke-prone spontaneously hypertensive 5/Dmcr rats were fed control or high-fat-cholesterol (HFC) diets for 2, 8, and 14 weeks. Although HFC-induced hepatic fibrosis was markedly less severe in females than in males, only minor gender differences were observed in expression levels of cytochrome P450 enzymes (CYP)7A1, CYP8B1 CYP27A1, and CYP7B1, and multidrug resistance-associated protein 3, and bile salt export pump, which are involved in fibrosis-related bile acid (BA) kinetics. However, the BA detoxification-related enzymes UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) 2A1, and the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), were strongly suppressed in HFC-fed males, and were only slightly changed in HFC-diet fed females. Expression levels of the farnesoid X receptor and its small heterodimer partner were similarly regulated in a gender-dependent fashion following HFC feeding. Hence, the pronounced female resistance to HFC-induced liver damage likely reflects sustained expression of the nuclear receptors CAR and PXR and the BA detoxification enzymes UGT and SULT.

Combination of Hypertension Along with a High Fat and Cholesterol Diet Induces Severe Hepatic Inflammation in Rats via a Signaling Network Comprising NF-κB, MAPK, and Nrf2 Pathways

Populations with essential hypertension have a high risk of nonalcoholic steatohepatitis (NASH). In this study, we investigated the mechanism that underlies the progression of hypertension-associated NASH by comparing differences in the development of high fat and cholesterol (HFC) diet-induced NASH among three strains of rats, i.e., two hypertensive strains comprising spontaneously hypertensive rats and the stroke-prone spontaneously hypertensive 5/Dmcr, and the original Wistar Kyoto rats as the normotensive control. We investigated histopathological changes and molecular signals related to inflammation in the liver after feeding with the HFC diet for 8 weeks. The diet induced severe lobular inflammation and fibrosis in the livers of the hypertensive rats, whereas it only caused mild steatohepatitis in the normotensive rats. An increased activation of proinflammatory signaling (transforming growth factor-β1/mitogen-activated protein kinases pathway) was observed in the hypertensive strains fed with the HFC diet. In addition, the HFC diet suppressed the nuclear factor erythroid 2-related factor 2 pathway in the hypertensive rats and led to lower increases in the hepatic expression of heme oxygenase-1, which has anti-oxidative and anti-inflammatory activities. In conclusion, these signaling pathways might play crucial roles in the development of hypertension-associated NASH.

Heat stress-induced phosphorylation of FoxO3a signalling in rat skeletal muscle

AIM

A recent study demonstrated that FoxO3a was directly induced by the overexpression of Hsp72 in rat soleus muscle. However, whether heat stress treatment induces FoxO3a phosphorylation in rat skeletal muscle remains unclear. This study examined the effects of heat stress on the regulation of the FoxO3a signalling pathway in rat skeletal muscle.

METHODS

Thirty-two male Wistar rats (15 weeks old) were randomly assigned into two groups; sedentary control group (Sed, n = 8) and experimental group (n = 24). After an overnight fast, one leg of each rat (HS leg) in the experimental group was immersed in hot water (43 °C) for 30 min, and the soleus and plantaris muscles in both legs were removed immediately (0 min), 30 min, 60 min, or 24 h after the heat stress (n = 6 each group). The contralateral, non-heated leg in the experimental group served as an internal control (CT leg).

RESULTS

Heat stress treatment resulted in a significant increase in FoxO3a phosphorylation (Ser253) in the soleus and plantaris muscles of heat-stressed legs after 24 h. Hsp72 expression in heat-stressed legs was significantly higher at 60 min and 24 h in these muscles. Activation of the PTEN/Akt and MEK/ERK pathways was also observed in these muscles immediately after stress, but not at 24 h. There were no differences in FoxO1 and AMPKα phosphorylation in either muscle.

CONCLUSION

Heat stress in rat skeletal muscle induces phosphorylation of FoxO3a signalling, and it may be related to Hsp72 upregulation, and the activation of the PTEN/Akt and MEK/ERK pathways.

Efficacy of Whole Bowel Irrigation Using Solutions with or without Adsorbent in the Removal of Paraquat in Dogs

1 The efficacy of whole bowel irrigation with a solution containing either polyethylene glycol (PEG) with electrolyte or an adsorbent (Kayexalate™) with a cathartic (sorbitol) was investigated in 18 dogs who had been given 250 mg kg -1 paraquat dichloride via a jejunal tube to eliminate the influence of gastric absorption.

2 Plasma paraquat concentrations 2 and 3 h after the initiation of bowel irrigation and at the end of the study (5 h later) were significantly lower in the bowel irrigation groups than in the control (no bowel irrigation) group.

3 The total body clearances of paraquat in the bowel irrigation groups were significantly greater than in the control group.

4 There were no significant differences between the two different irrigation solution groups in plasma paraquat concentration, the area under the plasma concentration time curve and the total body clearance.

5 In the PEG with electrolyte group, about 70% of the administered dose of paraquat was removed by means of bowel irrigation (n=4).

6 The adjunction of the adsorbent had no beneficial effects.

7 Haemodynamic changes associated with whole bowel irrigation were unremarkable except that right atrial and pulmonary arterial pressures were elevated in the latter part of the study.

Metallothionein MT2A A-5G Polymorphism as a Risk Factor for Chronic Kidney Disease and Diabetes: Cross-Sectional and Cohort Studies

Metallothioneins (MTs) are proteins that protect cells from toxic agents such as heavy metal ions or reactive oxygen species. MT2A A-5G is a single nucleotide polymorphism in the promoter region of the MT2A gene, and the minor G allele results in lower transcription efficiency. We aimed to elucidate associations between MT2A A-5G and risks of 2 diseases potentially related to lowered MT expression, chronic kidney disease (CKD), and diabetes mellitus (DM), in a community-dwelling population. Study subjects were Nagoya city residents participating in the Japan Multi-Institutional Collaborative Cohort Study (J-MICC) Daiko Study, comprised 749 men and 2,025 women, aged 39-75 years. CKD (>stage 3) and DM were defined by standard guidelines. Associations were evaluated using logistic regression models with adjustments for age, sex and potential confounders in a cross-sectional study, and verified in a 5-year longitudinal study. Odds ratios (OR [95% confidence interval]) were calculated relative to the AA genotype. Serum MT (I + II), Cd and zinc levels were also determined by genotype. The OR of the GG genotype for CKD risk was 3.98 (1.50, 10.58) in the cross-sectional study and 5.17 (1.39, 19.28) in the longitudinal study. The OR of the GA genotype for DM was 1.86 (1.26, 2.75) in the cross-sectional study and 2.03 (1.19, 3.46) in the longitudinal study. MT2A A-5G may be associated with CKD and DM risks. This polymorphism is a promising target for evaluations of CKD and DM risks with possible involvement of low-dose chronic exposure to environmental pollutants.

[Mechanism Analysis and Prevention of Pathogenesis of Nonalcoholic Steatohepatitis]

Nonalcoholic fatty liver disease (NAFLD) is a common disease in humans having a broad spectrum of liver histology from simple fatty liver to mixed inflammatory cell infiltration and fibrosis (nonalcoholic steatohepatitis, NASH), which is a more severe and progressing form. NASH/NAFLD is significantly associated with lifestyle such as diet and exercise, obesity, insulin resistance, type 2 diabetes, dyslipidemia and hypertension. Age and gender are also associated with the development. On the other hand, NAFLD has been found in a high percentage of nonobese individuals in the Asia-Pacific area. Some characteristic animal models of NAFLD/NASH have been developed to clarify the pathogenesis of human NAFLD/NASH. We have recently developed a novel NASH rat model (stroke-prone spontaneously hypertensive rats, SHRSP5/Dmcr), which showed hepatic steatosis and inflammation at 2 weeks, ballooning, macrovesicular steatosis and fibrosis at 8 weeks, and bridging fibrosis at 14 weeks by feeding of high-fat and -cholesterol (HFC) diet alone. This animal model does not have obesity, insulin resistance or diabetes. Therefore, this may be an excellent animal model of human NASH/NAFLD without obesity and diabetes. Sex and strain differences observed in fibrogenesis by the HFC diet in SHRSP5/Dmcr may be associated with the sensitivity to detoxification enzymes in the liver, because the levels of UGP-glucuronosyltransferase and sulfotransferase and their regulating nuclear receptors only decreased in male SHRSP5/Dmcr rats, but not in female and SHRSP rats. This suggests the importance of phase II reactions of drug-metabolizing enzymes in NASH progression. Importantly, SHRSP5/Dmcr rats are spontaneously hypertensive; therefore, when we use the original strain Wistar Kyoto, which has normal blood pressure, the involvement of blood pressure in the development of human NASH/NAFLD may also be clarified.

Importance of detoxifying enzymes in differentiating fibrotic development between SHRSP5/Dmcr and SHRSP rats

OBJECTIVES

High-fat and -cholesterol diet (HFC) induced fibrotic steatohepatitis in stroke-prone spontaneously hypertensive rat (SHRSP) 5/Dmcr, the fifth substrain from SHRSP, by dysregulating bile acid (BA) kinetics. This study aimed to clarify the histopathological and BA kinetic differences in HFC-induced fibrosis between SHRSP5/Dmcr and SHRSP.

METHODS

Ten-week-old male SHRSP5/Dmcr and SHRSP were randomly allocated to groups and fed with either control diet or HFC for 2 and 8 weeks. The liver histopathology, biochemical features, and molecular signaling involved in BA kinetics were measured.

RESULTS

HFC caused more severe hepatocyte ballooning, macrovesicular steatosis and fibrosis in SHRSP5/Dmcr than in SHRSP. It was noted that fibrosis was disproportionately formed in retroperitoneal side of both strains. As for BA kinetics, HFC greatly increased the level of Cyp7a1 and Cyp7b1 to the same degree in both strains at 8 weeks, while multidrug resistance-associated protein 3 was greater in SHRSP5/Dmcr than SHRSP. The diet decreased the level of bile salt export pump by the same degree in both strains, while constitutive androstane receptor, pregnane X receptor, and UDP-glucuronosyltransferase activity more prominent in SHRSP5/Dmcr than SHRSP at 8 weeks. In the fibrosis-related genes, only expression of collagen, type I, alpha 1 mRNA was greater in SHRSP5/Dmcr than SHRSP.

CONCLUSIONS

The greater progression of fibrosis in SHRSP5/Dmcr induced by HFC may be due to greater suppression of UDP-glucuronosyltransferase activity detoxifying toxicants, such as hydrophobic BAs.

Efficacy of Dietary Lipid Control in Healing High-Fat and High-Cholesterol Diet-Induced Fibrotic Steatohepatitis in Rats

Nonalcoholic steatohepatitis is related to lifestyle, particularly to dietary habits. We developed diet-induced fibrotic steatohepatitis model stroke-prone spontaneously hypertensive 5/Dmcr (SHRSP5/Dmcr) rats showing steatosis, hepatic inflammation, and severe fibrosis induced by high-fat and -cholesterol (HFC) diet feeding. We aimed to clarify the efficacy of dietary intervention on the disease before and after the appearance of fibrosis. Male SHRSP5/Dmcr rats were divided into 9 groups; of these, 6 groups were fed control or HFC diet for several weeks and the remaining 3 groups represented the dietary intervention groups, which were fed the control diet after HFC diet feeding for 2 (before the appearance of fibrosis) or 8 (after the appearance of fibrosis) weeks. Dietary intervention before the appearance of fibrosis significantly improved the steatosis and reset the increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and serum total cholesterol (TC) levels. However, dietary intervention after the appearance of fibrosis was unable to reset the levels of hepatic TC, serum ALT, and fibrogenesis-related markers and had only a minor influence on hepatic fibrosis, although it reset the increased expression of transforming growth factor (TGF)-β1 and α-smooth muscle actin (SMA). It was noted that dietary intervention improved the increased AST levels; however, aggregated CD68-positive cells were still observed around the fibrosis area, which may be related to the findings of inflammatory cytokine mRNAs. Taken together, dietary intervention for fibrotic steatohepatitis improved steatosis, although it could not completely improve fibrosis.

A trial to find appropriate animal models of dichloropropane-induced cholangiocarcinoma based on the hepatic distribution of glutathione S-transferases

OBJECTIVES

It has been reported that 1,2-Dichloropropane (DCP) induced cholangiocarcinoma (CCA) in offset color proof-printing workers. However, exposure to DCP by inhalation or gavage for 2 year did not induce CCA in mice and rats. The present study mapped the hepatic distribution of GST, which is known to activate dihalogenated alkanes, and proliferative and fibrotic changes in bile ducts in various species to find the most appropriate animal model of DCP-induced CCA.

METHODS

First, 12 each of C57BL/6J mice, Balb/cA mice, F344 rats, Syrian hamsters, and guinea pigs were divided into four equal groups and exposed to DCP at 0, 300, 1,000, or 3,000 ppm 8 hours/day for 7 days. Second, 32 Balb/cA mice and 32 Syrian hamsters were each divided into four equal groups and exposed to DCP at 0, 200, 400, and 800 ppm 6 hours/day for 14 days. After the last exposure, the animals were decapitated, and the livers were dissected out for histopathological evaluation. Immunostaining was conducted to determine the distribution of GSTT1, GSTM1, and GSTPi, as well as the expression of proliferation marker Ki67.

RESULTS

GSTT1, GSTM1, and GSTPi were expressed in both hepatocytes and bile duct cells in all control and exposed animals. There was no clear difference in the expression of Ki67 between the exposed groups and the control. No fibrotic changes were observed in any species or strains examined.

CONCLUSIONS

Expression of GSTT1 or other GST isozymes might not explain the difference in sensitivity of hepatocytes and the bile duct to DCP between humans and rodents.

Association of maternal whole blood fatty acid status during the prenatal period with term birth dimensions: a cross-sectional study

OBJECTIVE

To investigate selected fatty acid (FA) profiles in maternal whole blood during normal pregnancy and to evaluate their associations with term birth dimensions.

METHODS

We characterized nine major maternal blood FAs representing four FA families during the second and third trimester of pregnancy, and explored their associations with birth weight, length, and chest or head circumferences by multivariate regression models, using data from 318 mother-newborn pairs of the Hokkaido Study.

RESULTS

The absolute and/or relative contents of maternal blood docosahexaenoic acid and arachidonic acid were lowest at 35-41 gestational weeks during pregnancy, as was the essential FA status index. Different from palmitic and stearic acids, palmitoleic and oleic acid contents were higher at 35-41 gestational weeks than those at 23-31 gestational weeks. Three FA components were identified through principal component analysis, and were used in association analysis. Component 3, which was positively and significantly loaded by eicosapentaenoic acid (EPA), was associated with chest circumference [β=0.281, 95% confidence interval (CI): 0.006, 0.556] at 35-41 gestational weeks (P=0.046). No significant associations were observed for Component 1 and 2 loaded by FAs except EPA.

CONCLUSION

Maternal blood EPA content may have an important influence on infant chest circumference.

Traditional and ankle-specific vertical jumps as strength-power indicators for maximal sprint acceleration

AIM

This study aimed to determine the demand of strength-power capabilities represented by traditional and ankle-specific vertical jump modalities ‑ squat jump (SJ), counter-movement jump (CMJ), rebound-continuous jump (RJ), rebound-continuous ankle jump (AJ) ‑ relative to sprint acceleration ability during the entire acceleration phase of maximal sprint.

METHODS

Nineteen male sprinters performed a 60-m maximal sprint and various vertical jumps. Correlation coefficients among the vertical jump performances and between those and the 60-m sprint time and sprint acceleration at each step were calculated.

RESULTS

There were significant relationships between the 60-m sprint time and SJ height, CMJ height, AJ height, and AJ index. AJ height and index had no correlation with any other jump variables. Acceleration was significantly correlated with SJ height from the 6th to the 10th steps (r=0.48-0.51) and with CMJ height from the 5th to the 11th steps (r=0.46-0.54). Acceleration was also correlated with the AJ index from the 14th to the 19th steps (r=0.48-0.54). Acceleration had no correlation with the RJ index at any step.

CONCLUSION

The results suggest that the AJ allows assessment of different reactive strengths compared with traditional jump modalities. To accelerate effectively, the explosive strengths of the SJ and CMJ are important during the early stage of acceleration (from 6.6±0.4 to 17.5±0.8 m), and the reactive strength represented by the AJ is necessary during the later stage of acceleration (from 23.4±1.0 to 33.7±1.4 m). Sprinters and coaches should be aware of the different demands of strength-power capability for effective acceleration.

Association between maternal exposure to di(2-ethylhexyl) phthalate and reproductive hormone levels in fetal blood: the Hokkaido study on environment and children's health

Prenatal di(2-ethylhexyl) phthalate (DEHP) exposure can produce reproductive toxicity in animal models. Only limited data exist from human studies on maternal DEHP exposure and its effects on infants. We aimed to examine the associations between DEHP exposure in utero and reproductive hormone levels in cord blood. Between 2002 and 2005, 514 pregnant women agreed to participate in the Hokkaido Study Sapporo Cohort. Maternal blood samples were taken from 23-35 weeks of gestation and the concentration of the primary metabolite of DEHP, mono(2-ethylhexyl) phthalate (MEHP), was measured. Concentrations of infant reproductive hormones including estradiol (E2), total testosterone (T), and progesterone (P4), inhibin B, insulin-like factor 3 (INSL3), steroid hormone binding globulin, follicle-stimulating hormone, and luteinizing hormone were measured from cord blood. Two hundred and two samples with both MEHP and hormones' data were included in statistical analysis. The participants completed a self-administered questionnaire regarding information on maternal characteristics. Gestational age, birth weight and infant sex were obtained from birth records. In an adjusted linear regression analysis fit to all study participants, maternal MEHP levels were found to be associated with reduced levels of T/E2, P4, and inhibin B. For the stratified analyses for sex, inverse associations between maternal MEHP levels T/E2, P4, inhibin B, and INSL3 were statistically significant for males only. In addition, the MEHP quartile model showed a significant p-value trend for P4, inhibin B, and INSL3 decrease in males. Since inhibin B and INSL3 are major secretory products of Sertoli and Leydig cell, respectively, the results of this study suggest that DEHP exposure in utero may have adverse effects on both Sertoli and Leydig cell development in males, which agrees with the results obtained from animal studies. Comprehensive studies investigating phthalates' exposure in humans, as well as their long-term effects on reproductive development are needed.

A possible role of chenodeoxycholic acid and glycine-conjugated bile acids in fibrotic steatohepatitis in a dietary rat model

BACKGROUND AND AIMS

Our previous study indicated that hepatic bile acids (BAs) may have deposited and stimulated the pathogenesis of a high fat-cholesterol (HFC) diet-induced fibrotic steatohepatitis in stroke-prone spontaneously hypertensive 5/Dmcr rats, based on dysregulated BA homeostasis pathways. We aimed to further characterize BA profiles in liver and evaluate their relationships to liver injury using this model.

METHODS

Hepatic 21 BA levels were determined by ultra-performance liquid chromatography-tandem mass spectrometry, and their correlations with macrovesicular steatosis score, serum alanine aminotransferase (ALT) level and quantified fibrotic area were assessed using Spearman and Pearson correlations.

RESULTS

Compared to control, BAs highly accumulated in HFC-fed rat liver at 2 weeks: cholic acid (CA), deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) were major species, thereafter, levels of CA and DCA declined, but CDCA species persistently increased, which induced a decrease in total CA/total CDCA ratio at 8 and 14 weeks. CDCA species positively, while total CA/total CDCA negatively, correlated with macrovesicular steatosis score, serum ALT and quantified fibrotic area. Unlike control, total ursodeoxycholic acid was minor in HFC-fed rat liver, and inversely correlated to aforementioned indicators of liver injury; total glyco-BAs, rather than tauro-BAs, were predominant in HFC-fed rat liver, and positively correlated with macrovesicular steatosis score. Moreover, its ratio to total tauro-BAs positively correlated with each parameter of liver injury, while inverse associations were detected for total tauro-BAs.

CONCLUSIONS

Hepatic BA accumulation may potentiate liver disease. CDCA and glyco-BAs play a more important role in the pathogenesis of fibrotic steatohepatitis.

Effects of walking combined with restricted leg blood flow on mTOR and MAPK signalling in young men

Walking combined with blood flow reduction (BFR-walk) elicits muscle hypertrophy. However, the skeletal muscle intracellular signalling behind this response is currently unknown.

AIM

To investigate the effects of BFR-walk on mechanistic target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) signalling pathways in young men.

METHODS

Six young men performed 20 min of treadmill walking at 55% of their predetermined maximum oxygen uptake. A pressure cuff belt was applied to the most proximal thigh of only one leg (BFR-Leg, external compression was 240 mmHg), whereas the other leg (CON-Leg) was without BFR during walking. Muscle biopsies were taken from the vastus lateralis of the CON-Leg before exercise and in both legs 3 h after exercise.

RESULTS

Erk1/2 phosphorylation levels were significantly (P < 0.05) increased after exercise in both legs; however, only the BFR-Leg saw an increased phosphorylation of p38. For mTOR signalling, there were no changes in Akt, mTOR or S6K1 phosphorylation levels before or after walking. However, eEF2 phosphorylation level was significantly (P < 0.05) lower for the BFR-Leg 3 h after walking compared with CON-Leg.

CONCLUSION

BFR-walk exercise may activate some intracellular signalling cascades that are associated with muscle hypertrophy in young men.

Association of acceleration with spatiotemporal variables in maximal sprinting

This study clarified the association between acceleration and the rates of changes in spatiotemporal variables on a step-to-step basis during the entire acceleration phase of maximal sprinting. 21 male sprinters performed a 60-m sprint, during which step-to-step acceleration and rates of changes in step length (RSL) and step frequency (RSF) were calculated. The coefficients of correlation between acceleration and other variables were tested at each step. There were positive correlations between acceleration and the RSF up to the second step. Acceleration was positively correlated with the RSL from the 5(th) to the 19(th) step. At the third and from the 16(th) to the 22(nd) step and from the 20(th) to the 21(st) step, there was no significant correlation, but weak relationships were found between acceleration and the RSF and RSL. The results suggest that the acceleration phase can be divided into 3 sections, and for sprinting to be effective, it is important to accelerate by increasing the step frequency to the third step, increasing the step length from the 5(th) to the 15(th) step, and increasing the step length or frequency (no systematic relative importance of step length or frequency) from the 16(th) step in the entire acceleration phase.

Effect of NS-018, a selective JAK2V617F inhibitor, in a murine model of myelofibrosis

A single somatic mutation, V617F, in Janus kinase 2 (JAK2) is one of the causes of myeloproliferative neoplasms (MPNs), including primary myelofibrosis, and the JAK2V617F mutant kinase is a therapeutic target in MPN. However, inhibition of wild-type (WT) JAK2 can decrease the erythrocyte or platelet (PLT) count. Our selective JAK2 inhibitor, NS-018, suppressed the growth of Ba/F3 cells harboring JAK2V617F more strongly than that of cells harboring WT JAK2. The 4.3-fold JAK2V617F selectivity of NS-018 is higher than the 1.0- to 2.9-fold selectivity of seven existing JAK2 inhibitors. NS-018 also inhibited erythroid colony formation in JAK2V617F transgenic mice at significantly lower concentrations than in WT mice. In keeping with the above results, in a JAK2V617F bone marrow transplantation mouse model with a myelofibrosis-like disease, NS-018 reduced leukocytosis and splenomegaly, improved bone marrow fibrosis and prolonged survival without decreasing the erythrocyte or PLT count in the peripheral blood. By exploring the X-ray co-crystal structure of NS-018 bound to JAK2, we identified unique hydrogen-bonding interactions between NS-018 and Gly993 as a plausible explanation for its JAK2V617F selectivity. These results suggest that NS-018 will have therapeutic benefit for MPN patients through both its efficacy and its reduced hematologic adverse effects.