Characterization of Urate Transport System in JAR and JEG-3 Cells, Human Trophoblast-derived Cell Lines

Urate (uric acid) is the major inert end product of purine metabolism in humans. Since it is water soluble, it requires a membranous protein called transporter for its permeation across the plasma membrane. Increased blood urate level is often seen in preeclampsia, but its precise mechanism remains unknown. Syncytiotrophoblasts function as a barrier between maternal blood and fetal one so called “blood-placental barrier”. So far, the expression of several urate transporters was identified in these cells, but it is still unclear about their contribution to urate handling in blood-placental barrier. In this study, we investigated the expression of urate transporters and the properties of ［14C］urate transport in both JAR and JEG-3, human choriocarcinoma cells as a model of human placenta. Conventional PCR analysis revealed that both JAR and JEG-3 cells express strongly breast cancer resistance protein (BCRP/ABCG2) mRNA. Uptake of ［14C］urate by these cells is time-dependent with Na＋- and Cl－-independent and voltage-insensitive manner and is not inhibited by benzbromarone, a representative renal urate transport inhibitor. Then, we focused on BCRP which shows strong mRNA expression and found that these cells have urate efflux property that is sensitive to fumitremorgin C (FMC), a BCRP inhibitor. These results suggest that BCRP is one of the important components for urate handling in human placenta in pathophysiological condition such as preeclampsia

Sedentary Time and All-Cause Mortality

BACKGROUND: This study aimed to determine the association between sedentary time and mortality with regard to leisure‐time physical activity with or without cardiometabolic diseases such as hypertension, dyslipidemia, and diabetes mellitus. METHODS AND RESULTS: Using data from the J‐MICC (Japan Multi‐Institutional Collaborative Cohort) Study, 64 456 participants (29 022 men, 35 434 women) were analyzed. Hazard ratios (HRs) and 95% CIs were used to characterize the relative risk of all‐cause mortality to evaluate its association with sedentary time (categorical variables: <5, 5 to <7, 7 to <9, ≥9 h/d and 2‐hour increments in exposure) according to the self‐reported hypertension, dyslipidemia, and diabetes mellitus using a Cox proportional hazards model. A total of 2257 participants died during 7.7 years of follow‐up. The corresponding HRs for each 2‐hour increment in sedentary time among participants with all factors, no factors, hypertension, dyslipidemia, and diabetes mellitus were 1.153 (95% CI, 1.114–1.194), 1.125 (95% CI, 1.074–1.179), 1.202 (95% CI, 1.129–1.279), 1.176 (95% CI, 1.087–1.273), and 1.272 (95% CI, 1.159–1.396), respectively. Furthermore, when analyzed according to the combined different factors (hypertension, dyslipidemia, and diabetes mellitus), HRs increased with each additional factor, and participants reporting all 3 conditions had the highest HR of 1.417 (95% CI, 1.162–1.728) independently of leisure‐time metabolic equivalents. CONCLUSIONS: The association between sedentary time and increased mortality is stronger among patients with hypertension, dyslipidemia, and diabetes mellitus regardless of leisure‐time physical activity in a large Japanese population

Association of skipping breakfast and short sleep duration with the prevalence of metabolic syndrome in the general Japanese population : Baseline data from the Japan Multi-Institutional Collaborative cohort study

The purpose of the study was to investigate sex-specific associations of skipping breakfast and short sleep duration with metabolic syndrome (MetS) and their interaction. We analyzed baseline data of 14,907 men and 14,873 women aged 35–69 years, who participated in the Japan Multi-Institutional Collaborative Cohort Study from 2005. MetS was diagnosed using a modification of the National Cholesterol Education Program Adult Treatment Panel III revised definition (NCEP-R 2005), using body mass index instead of waist circumference. Breakfast consumption was classified into two categories: ≥6 days/week (consumers) or <6 days/week (skippers). Sleep duration was classified into three categories: <6h, 6 to <8 h, and ≥8 h/day. Multivariate logistic regression analysis was performed to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) and examine the presence of interaction. In men, skipping breakfast and short sleep duration were independently associated with an increased prevalence of MetS (OR 1.26, 95%CI 1.12–1.42 and OR 1.28, 95%CI 1.12–1.45, respectively), obesity, and components of MetS. However, no significant interaction was observed between skipping breakfast and short sleep duration. In women, skipping breakfast and short sleep duration were associated with an increased prevalence of obesity, but not with MetS. These findings indicate that breakfast consumption and moderate sleep duration may be associated with a lower risk of MetS, particularly in men

Seven-plus hours of daily sedentary time and the subsequent risk of breast cancer : Japan Multi-Institutional Collaborative Cohort Study

This study aimed to investigate the association between daily sedentary time and the risk of breast cancer (BC) in a large Japanese population. The participants were 36,023 women aged 35–69 years from the Japan Multi-Institutional Collaborative Cohort Study. Cox proportional hazards analysis was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for BC incidence in relation to time spent sedentarily (categorical variables: <7 and ≥7 hours/day [h/d]). Additionally, the associations of BC incidence to the joint effect of sedentary time with each component of physical activity, such as leisure-time metabolic equivalents (METs), frequency of leisure-time physical activity, and daily walking time, were examined. During 315,189 person-years of follow-up, 554 incident cases of BC were identified. When compared to participants who spent <7 h/d sedentary, those who spent ≥7 h/d sedentary have a significantly higher risk of BC (HR, 1.36; 95% CI, 1.07–1.71). The corresponding HRs among participants who spent ≥7 h/d sedentary with more physical activity, such as ≥1 h/d for leisure-time METs, ≥3 days/week of leisure-time physical activity, and ≥1 h/d of daily walking were 1.58 (95% CI, 1.11–2.25), 1.77 (95% CI, 1.20–2.61), and 1.42 (95% CI, 1.10–1.83), respectively, compared with those who spent <7 h/d sedentary. This study found that spending ≥7 h/d of sedentary time is associated with the risk of BC. Neither leisure-time physical activity nor walking had a BC-preventive effect in those with ≥7 h/d of sedentary time

Smoking, Drinking, and Genetic Factors Affect HDL-cholesterol

Background: Environmental and genetic factors are suggested to exhibit factor-based association with HDL-cholesterol (HDL-C) levels. However, the population-based effects of environmental and genetic factors have not been compared clearly. We conducted a cross- sectional study using data from the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study to evaluate the population-based impact of smoking, drinking, and genetic factors on low HDL-C. Methods: Data from 11,498 men and women aged 35–69 years were collected for a genome-wide association study (GWAS). Sixty-five HDL-C-related SNPs with genome-wide significance (P <5 × 10−8) were selected from the GWAS catalog, of which seven representative SNPs were defined, and the population-based impact was estimated using population attributable fraction (PAF). Results: We found that smoking, drinking, daily activity, habitual exercise, egg intake, BMI, age, sex, and the SNPs CETP rs3764261, APOA5 rs662799, LIPC rs1800588, LPL rs328, ABCA1 rs2575876, LIPG rs3786247, and APOE rs429358 were associated with HDL-C levels. The gene-environmental interactions on smoking and drinking were not statistically significant. The PAF for low HDL-C was the highest in men (63.2%) and in rs3764261 (31.5%) of the genetic factors, and the PAFs of smoking and drinking were 23.1% and 41.8%, respectively. Conclusion: The present study showed that the population-based impact of genomic factor CETP rs3764261 for low HDL-C was higher than that of smoking and lower than that of drinking

Identification of Carnitine Transporter CT1 Binding Protein Lin-7 in Nervous System

_L-Carnitine is an essential component of mitochondrial fatty acid b-oxidation in the muscle and may control the acetyl moiety levels in the brain for acetylcholine synthesis. Carnitine transporter 1(CT1)is the high affinity _L-carnitine transporter whose localization was observed in the kidney, testis, liver, skeletal muscle and brain. To clarify the molecular mechanism of carnitine transport, we sought to find the interacting protein that may be related to the transport function of CT1. Using the intracellular C-terminal region of rat CT1 containing PDZ(PSD95/DLG/ZO-1)motif as bait, we performed the yeast two-hybrid screening against rat brain cDNA library. Thirty two positive clones were obtained from the 2.7×10^7 clones screened. One of them was PDZ domain-containing protein Lin-7. We found that Lin-7 interacts specifically with C-termini of CT1:deletion and mutation of the CT1 C-terminal PDZ-motif abolished the interaction with Lin-7 in the yeast two-hybrid assay. In addition, a PDZ domain within Lin-7 associates with the CT1 C-terminal. The association of CT1 with Lin-7 enhanced _L-carnitine transport activities in HEK293 cells although there is no statistical significance. Coexpression of Lin-7 and CT1 is identified in motor neurons of the spinal cord ventral horn together with Lin-2, a binding partner of Lin-7 known to assemble proteins involved in synaptic vesicle exocytosis and synaptic junctions. Therefore, Lin-7 interacts with CT1 and may regulate their subcellular distribution or function in central nervous system

ヒト ジンゾウ ニョウサン トランス ポーター URAT 1 ト スイヨウ セイ ヨード ケイ ゾウエイザイ IODIPAMIDE ノ ソウゴ サヨウ

降圧薬などいくつかの薬剤は本来の薬理作用とは別に尿酸降下作用を持つものがあり,水溶性ヨード系造影剤もその一つでiodipamideやdiatrizoateでの尿酸排泄亢進が報告されていた.長らく不明のままであった腎尿酸輸送機構の分子実体は2002年の腎尿細管尿酸トランスポーターURAT1(Urate Transporter 1)の分子同定によりその理解が飛躍的に進んだ.本研究ではURAT1と水溶性造影剤のiodipamideおよびdiatrizoateの相互作用を検討することで,その尿酸排泄促進作用の分子機序の解明を目的とする.URAT1の尿酸輸送活性の測定にはURAT1安定発現HEK293細胞(HEK-URAT1)細胞を用いた.IodipamideはHEK-URAT1細胞でのRI標識尿酸取込みを著明に阻害した(IC_:1.19±0.08?μM)のに対し,diatrizoateは1?mMまでの範囲では50%以上の阻害作用を示さなかった.1?mMまでのiodipamideはHEK-URAT1細胞の生存率に影響を与えなかった.IodipamideによるURAT1媒介尿酸輸送への阻害作用のキネティクス解析の結果,その阻害は競合阻害であり,阻害定数Ki値は11.03?μMであった.以上より,iodipamideは尿酸トランスポーターURAT1と相互作用をすることを初めて確認できた.このことからiodipamideは細胞外からURAT1の尿酸結合部位に結合し,競合して阻害を行うことで,腎尿細管の経上皮性尿酸再吸収を抑制し,ひいては血清尿酸値を低下させるものと考えられた.Drug-induced hypouricemia has been found in several drugs such as probenecid, benzbromarone and angiotensin II receptor blocker(ARB)losartan. Xray contrast agents such as iodipamide and diatrizoate, used for the intravenous cholangiography and excretory urography, were reported to have uricosuric effct beside their original action. After the molecular identification of renal apical urate transporter URAT1 as an entrance of urate into the epithelial cells of proximal tubules, this protein is thought to be major determinant for renal reabsorption of urate that affect the blood urate levels in human. The purpose of this study is to examine whether iodipamide and diatrizoate act on URAT 1 . In URAT 1 -stably expressing HEK293(HEK-URAT1)cells, iodipamide inhibited [^C] urate uptake dose-dependently(IC_ , 1.19±0.08 μM), while diatrizoate did not. Up to the concentration of 1 mM, iodipamide incubation for 24 hr did not affect the viability of HEK293-URAT1 cells. Lineweaver-Burk plot of the kinetic analysis by URAT1-mediated urate uptake with or without iodipamide indicated that its interaction occurs in a competitive manner(Ki:11.03 μM). These results suggest that uricosuric effect of iodipamide can be explained by the interaction of iodipamide with urate-binding site of URAT1, and the inhibition of urate reabsorption from extracellular side by iodipamide causes uricosuria leading to induce hypouricemia

Molecular Mechanism of the Urate-lowering Effects of Calcium Channel Blockers

Hyperuricemia has recently been recognized as one of the risk factors for cardiovascular diseases. Some calcium channel blockers(CCBs), commonly used in the treatment of hypertension, have been reported to decrease serum urate level. Here, we tried to elucidate the molecular mechanism of the urate-lowering effects of CCBs. We performed [^C]urate uptake in cells stably expressing human urate transporter 1, a major contributor of renal urate reabsorption and a major target of uricosuric drugs such as benzbromarone and losartan(HEK-URAT1), together with mock(HEK-mock)cells to analyze the uricosuric action of CCBs. We also measured the activity of human xanthine oxidase(XO)to determine whether CCBs have inhibitory effects on urate production. The CCBs tested were nifedipine, nilvadipine, nitrendipine, benidipine, nisoldipine, nicardipine, efonidipine, amlodipine, azelnidipine, verapamil and diltiazem. We found for the first time that at least seven CCBs in the dihydropyridine subgroup interacted with URAT1-mediated urate uptake in HEK-URAT1 cells. Among these CCBs, nifedipine, nilvadipine and nitrendipine strongly inhibited URAT1-mediated urate uptake. Their IC_s were 15.8, 0.018 and 0.40?μM, respectively. In contrast, urate production mediated by XO was weakly inhibited by nifedipine and nisoldipine. In summary, URAT1 interacted with various CCBs differently, whereas XO, a major enzyme for urate production in the liver, did not interact with most of CCBs. Although CCBs were not excreted from the urine basically, their urate-lowering effects may be associated with the inhibition of renal urate reabsorption mediated by renal urate transporters such as URAT1 with their metabolites, and the results for structure-activity information in this study will provide a clue for developing new uricosuric drugs targeting URAT1

Recent Advances in the Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease in which stenosis or obstruction of the pulmonary arteries (PAs) causes an increase in PA pressure, leading to right-sided heart failure and death. Basic research has revealed a decrease in the levels of endogenous vasodilators, such as prostacyclin, and an increase in the levels of endogenous vasoconstrictors, such as endothelin, in patients with PAH, leading to the development of therapeutic agents. Currently, therapeutic agents for PAH target three pathways that are selective for PAs: the prostacyclin, endothelin, and nitric oxide pathways. These treatments improve the prognosis of PAH patients. In this review, we introduce new drug therapies and provide an overview of the current therapeutic agents

Effectiveness of a barbed suture in the repair of bile duct injury during laparoscopic cholecystectomy: Report of two cases

Introduction: Bile duct injury during laparoscopic cholecystectomy occurs in rare cases. We report two cases using barbed suture for repair in bile duct injury during laparoscopic cholecystectomies. Presentation of cases: The first patient was a 73-year-old woman who underwent elective laparoscopic cholecystectomy for cholecystolithiasis. When the gallbladder was dissected from the bed, bile spillage was observed and an injured small bile duct was detected. The bile duct could not be managed using a titanium clip. The second patient was an 83-year-old woman who underwent emergent laparoscopic cholecystectomy for gallbladder torsion. After the gallbladder was dissected from the bed, bile spillage was observed. In both cases, a running suture, of absorbable monofilament 3-0 barbed suture, was used to laparoscopically repair the injuries. Discussion: Laparoscopic repair of a bile duct injury is technically challenging, especially in the gallbladder bed where suturing is very difficult because of the tangential approach and the risk of additional liver laceration. Barbed sutures have the benefit of being knotless, thus, performing a running suture is not difficult, even in laparoscopic procedures. Further, absorbable and monofilament threads are generally better suited for biliary surgery, compared with non-absorbable and braided sutures, because of the potential association of the other types of materials with bile duct stone and stricture formation. Conclusion: We believe that the V-Loc™ device is an effective and appropriate option for bile duct injuries that occur during laparoscopic cholecystectomies, particularly around the gallbladder bed, and it is especially useful for surgeons unfamiliar with intracorporeal knot tying