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Low birth weight (LBW) is a risk factor for chronic kidney disease (CKD) in later life and is becoming increasingly common in developed countries, including Japan. Furthermore, a serial decrease in birth weight has been associated with an increasing prevalence of CKD stage 2 in male Japanese adolescents. Sex-specific differences affect CKD susceptibility, and the association between birth weight and CKD in women, has not been elucidated. In this study, we investigated the sex-specific effect of LBW on renal function. Annual cross-sectional data of 2417 Japanese adolescents (males 1736; females 681), aged 15–16 years, were evaluated over 8 years (2007–2014). Over the study period, mean birth weights decreased significantly in males (p

Ketone bodies including β-hydroxybutyrate (β-OHB) have been shown to protect against ischemic tissue injury when present at low concentrations. We evaluated the impact of β-OHB on renal ischemia/reperfusion injury (IRI). Mice were treated with a continuous infusion of β-OHB using an osmotic mini-pump before and after IRI. We also tested the effects of increasing endogenous serum β-OHB levels by fasting. Renal IRI was attenuated by β-OHB treatment compared to saline control, with similar results in the fasting condition. β-OHB treatment reduced the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells and increased expression of forkhead transcription factor O3 (FOXO3), an upstream regulator of pyroptosis. Although β-OHB treatment did not impact markers of apoptosis, it decreased the expression of caspase-1 and proinflammatory cytokines, indicating that β-OHB blocked pyroptosis. In a human proximal tubular cell line exposed to hypoxia and reoxygenation, β-OHB reduced cell death in a FOXO3-dependent fashion. Histone acetylation was decreased in kidneys exposed to IRI and in proximal tubular cells exposed to hypoxia and reoxygenation, and this effect was ameliorated by β-OHB through the inactivation of histone deacetylases. In vitro, β-OHB treatment restored histone acetylation at the FOXO3 promoter. Consistent with epigenetic molecular effects, the renoprotective effects of β-OHB were still observed when the continuous infusion was stopped at the time of IRI. Thus, β-OHB attenuates renal IRI through anti-pyroptotic effects, likely mediated by an epigenetic effect on FOXO3 expression.

The Japanese hypertension guidelines report that essential hypertension is detected in 1–3% of upper elementary and high school students during blood pressure (BP) screenings. Hypertension in these age groups is an emerging public health concern mainly attributed to the rising rate of pediatric obesity. Considering the existence of BP tracking phenomenon, early preventive education and instruction are necessary, especially for male students with moderately elevated BP showing a tendency toward obesity, despite the low prevalence of hypertension in high school students. Students with a positive family history of hypertension and those born with low birth weight need the same measures. Lifestyle habits, such as increased alcohol intake, dramatically change once students begin university; thus, early education and instruction regarding the factors influencing BP are necessary. In particular, for male students with higher BP during high school, caution regarding increased body weight is required irrespective of their level of obesity. Young adults aged

Sleep is generally viewed as a period of recovery, but how the supply of cerebral blood flow (CBF) changes across sleep/wake states has remained unclear. Here, we directly observe red blood cells (RBCs) within capillaries, where the actual substance exchange between the blood and neurons/glia occurs, by two-photon microscopy. Across multiple cortical areas, average capillary CBF is largely increased during rapid eye movement (REM) sleep, whereas it does not differ between periods of active wakefulness and non-REM sleep. Capillary RBC flow during REM sleep is further elevated following REM sleep deprivation, suggesting that capillary CBF reflects REM sleep pressure. At the molecular level, signaling via adenosine A2a receptors is crucial; in A2a-KO mice, capillary CBF upsurge during REM sleep is dampened, and effects of REM sleep pressure are abolished. These results provide evidence regarding the dynamics of capillary CBF across sleep/wake states and insights to the underlying mechanisms., 睡眠中の脳のリフレッシュ機構を解明. 京都大学プレスリリース. 2021-08-27.

Objective To compare length of stay (LOS) in neonatal care for babies born extremely preterm admitted to networks participating in the International Network for Evaluating Outcomes of Neonates (iNeo). Study design Data were extracted for babies admitted from 2014 to 2016 and born at 24 to 28 weeks of gestational age (n = 28 204). Median LOS was calculated for each network for babies who survived and those who died while in neonatal care. A linear regression model was used to investigate differences in LOS between networks after adjusting for gestational age, birth weight z score, sex, and multiplicity. A sensitivity analysis was conducted for babies who were discharged home directly. Results Observed median LOS for babies who survived was longest in Japan (107 days); this result persisted after adjustment (20.7 days more than reference, 95% CI 19.3-22.1). Finland had the shortest adjusted LOS (−4.8 days less than reference, 95% CI –7.3 to −2.3). For each week's increase in gestational age at birth, LOS decreased by 12.1 days (95% CI –12.3 to −11.9). Multiplicity and male sex predicted mean increases in LOS of 2.6 (95% CI 2.0-3.2) and 2.1 (95% CI 1.6-2.6) days, respectively. Conclusions We identified between-network differences in LOS of up to 3 weeks for babies born extremely preterm. Some of these may be partly explained by differences in mortality, but unexplained variations also may be related to differences in clinical care practices and healthcare systems between countries.

Thromboembolism is one of the most serious complications of nephrotic syndrome (NS). Although the occurrence of renal vein thrombosis or deep vein thrombosis is well recognized in NS patients, they rarely develop cerebral venous thrombosis (CVT). The mortality rate of CVT patients is still approximately 10%, and 6-10% of patients who survive have a severe and permanent disability. Herein, we report the case of a 26-year-old woman with multiple thrombotic risk factors, including the presence of NS, use of oral contraceptives, smoking, and alcohol consumption who developed wide-range CVT. Undetermined fraction heparin, albumin and AT-III transfusion, and direct mechanical catheter thrombectomy were insufficient for the improvement of CVT. However, CVT eventually improved along with the remission of NS by prednisolone administration. This process indicates that in the management of CVT associated with NS, it is crucial to control the activity of NS. Currently, knowledge on the treatment for NS associated with CVT is limited, and this is a subject of urgent investigation.

Background The activation of NAD+-dependent deacetylase, Sirt1, by the administration of nicotinamide mononucleotide (NMN) ameliorates various aging-related diseases. Methods Diabetic db/db mice were treated with NMN transiently for 2 weeks and observed for effects on diabetic nephropathy (DN). Results At 14 weeks after the treatment period, NMN attenuated the increases in urinary albumin excretion in db/db mice without ameliorating hemoglobin A1c levels. Short-term NMN treatment mitigated mesangium expansion and foot process effacement, while ameliorating decreased Sirt1 expression and increased claudin-1 expression in the kidneys of db/db mice. This treatment also improved the decrease in the expression of H3K9me2 and DNMT1. Short-term NMN treatment also increased kidney concentrations of NAD+ and the expression of Sirt1 and nicotinamide phosphoribosyltransferase (Nampt), and it maintained nicotinamide mononucleotide adenyltransferase1 (Nmnat1) expression in the kidneys. In addition, survival rates improved after NMN treatment. Conclusions Short-term NMN treatment in early-stage DN has remote renal protective effects through the upregulation of Sirt1 and activation of the NAD+ salvage pathway, both of which indicate NMN legacy effects on DN.

The progression of chronic kidney disease (CKD) cannot be completely inhibited. We first explored factors contributing to CKD progression in patients with CKD in a prospective observational study. In the next phase, we focused on the effects of aldosterone, conducting a single-blinded placebo-controlled study using the selective mineralocorticoid receptor antagonist (MRA), eplerenone (25 mg/day). We recruited patients with CKD stage 2 and 3 whose plasma aldosterone concentration was above 15 ng/dL based on the prior data of a prospective observational study. In the CKD cohort study (n = 141), baseline plasma aldosterone concentration was identified as an independent contributory factor for the future rate of change in estimated glomerular filtration rate (eGFR). When the cut-off value for aldosterone was set at 14.5 ng/dL, the decline rate was significantly higher in patients with higher plasma aldosterone concentration (− 1.22 ± 0.39 ml/min/1.73 m2/year vs. 0.39 ± 0.40 ml/min/1.73 m2/year, p = 0.0047). In the final intervention study, in the eplerenone group, eGFR dropped at 6 months after the initiation of the study, and thereafter eGFR was maintained until the end of the study. At 24 months and 36 months, eGFR was significantly higher in the eplerenone group than in the placebo group. In conclusion, MRA can be an effective strategy in preventing CKD progression, especially in patients with high plasma aldosterone.

Background Very preterm infants are at high risk of death or severe morbidity. The objective was to determine the significance of severe congenital heart defects ( CHDs ) for these risks. Methods and Results This cohort study included infants from 10 countries born from 2007–2015 at 24 to 31 weeks’ gestation with birth weights CHDs were defined by International Classification of Diseases, Ninth Revision ( ICD‐9 ) and Tenth ( ICD‐10 ) codes and categorized as those compromising systemic output, causing sustained cyanosis, or resulting in congestive heart failure. The primary outcome was in‐hospital mortality. Secondary outcomes were neonatal brain injury, necrotizing enterocolitis, bronchopulmonary dysplasia, and retinopathy of prematurity. Adjusted and propensity score–matched odds ratios ( ORs ) were calculated. Analyses were stratified by type of CHD , gestational age, and network. A total of 609 (0.77%) infants had severe CHD and 76 371 without any malformation served as controls. The mean gestational age and birth weight were 27.8 weeks and 1018 g, respectively. The mortality rate was 18.6% in infants with CHD and 8.9% in controls (propensity score–matched OR , 2.30; 95% CI , 1.61–3.27). Severe CHD was not associated with neonatal brain injury, necrotizing enterocolitis, or retinopathy of prematurity, whereas the OR for bronchopulmonary dysplasia increased. Mortality was higher in all types, with the highest propensity score–matched OR (4.96; 95% CI, 2.11–11.7) for CHD causing congestive heart failure. While mortality did not differ between groups at OR for mortality in infants with CHD increased to 10.9 (95% CI, 5.76–20.70) at 31 weeks’ gestational age. Rates of CHD and mortality differed significantly between networks. Conclusions Severe CHD is associated with significantly increased mortality in very preterm infants.

Background and aims: Low birth weight is associated not only with poor birth outcome but also chronic health conditions such as hypertension in later life. B-type natriuretic peptide (BNP) is a prognostic factor of cardiovascular events in the general population. However, the association between birth weight and BNP remains unclear. Here, we examined the relationships among birth weight and risk factors for atherosclerosis, including BNP, in Japanese workers. Methods: A total of 1109 (517 male, 592 female; age 40–70 years) participants in an annual medical checkup were enrolled. Subjects were divided into three groups according to birth weight, and the associations between their birth weight and risk factors for atherosclerosis were examined by statistical analysis. Results: Jonckheere–Terpstra trend test according to birth weight category revealed that although birth weight was not correlated with BNP level, it was inversely associated with HbA1c in men and with diastolic blood pressure in women. Correlation coefficient tests for both categorical and continuous birth weight data confirmed the trend test findings. Multiple regression analysis indicated that birth weight was an explanatory factor for HbA1c in men and for diastolic blood pressure in women. Conclusions: Although no significant association was observed between birth weight and BNP, inverse associations between birth weight and HbA1c in men and diastolic blood pressure in women were found. These findings suggest that birth weight may partially predict future risk of cardiovascular events.

The amount, quality, and diurnal pattern of sleep change greatly during development. Developmental changes of sleep/wake architecture are in a close relationship to brain development. The fragmentation of wake episodes is one of the salient features in the neonatal period, which is also observed in mature animals and human individuals lacking neuropeptide orexin/hypocretin signaling. This raises the possibility that developmental changes of lateral hypothalamic orexin neurons are relevant to the development of sleep/wake architecture. However, little information is available on morphological and physiological features of developing orexin neurons. To address the cellular basis for maturation of the sleep/wake regulatory system, we investigated the functional development of orexin neurons in the lateral hypothalamus. The anatomical development as well as the changes in the electrophysiological characteristics of orexin neurons was examined from embryonic to postnatal stages in orexin-EGFP mice. Prepro-orexin promoter activity was detectable at embryonic day (E) 12.0, followed by expression of orexin A after E14.0. The number of orexin neurons and their membrane capacitance reached similar levels to adults by postnatal day (P) 7, while their membrane potentials, firing rates, and action potential waveforms were developed by P21. The hyperpolarizing effect of serotonin, which is a major inhibitory signal for adult orexin neurons, was detected after E18.0 and matured at P1. These results suggest that the expression of orexin peptides precedes the maturation of electrophysiological activity of orexin neurons. The function of orexin neurons gradually matures by 3 weeks after birth, coinciding with maturation of sleep/wake architecture.

A growing body of evidence suggests that dopamine plays a role in sleep-wake regulation, but the dopamine-producing brain areas that control sleep-wake states are unclear. In this study, we chemogenetically activated dopamine neurons in the ventral midbrain of mice to examine the role of these neurons in sleep-wake regulation. We found that activation of dopamine neurons in the ventral tegmental area (VTA), but not in the substantia nigra, strongly induced wakefulness, although both cell populations expressed the neuronal activity marker c-Fos after chemogenetic stimulation. Analysis of the pattern of behavioral states revealed that VTA activation increased the duration of wakefulness and decreased the number of wakefulness episodes, indicating that wakefulness was consolidated by VTA activation. The increased wakefulness evoked by VTA activation was completely abolished by pretreatment with the dopamine D2/D3 receptor antagonist raclopride, but not by the D1 receptor antagonist SCH23390. These findings indicate that the activation of VTA dopamine neurons promotes wakefulness via D2/D3 receptors.

Background Low birthweight (LBW) is a worldwide public health problem, demonstrating an increasing incidence in developed countries, including Japan. LBW is also a risk factor for later development of chronic kidney disease (CKD). To date, studies have not evaluated the population impacts of increasing LBW rates on renal function. Methods Estimated glomerular filtration rate (eGFR) was evaluated in 3737 Japanese adolescent males (15–16 years old) using annual cross-sectional data over an 18-year period (1998–2015). Results Between the initial (1998–2003) and final (2010–15) periods of the study, the mean birthweight decreased from 3213.4 ± 383.8 to 3116.2 ± 382.3 g and the LBW rate increased from 2.5 to 5.5% (both P ≤ 0.01). Additionally, the mean eGFR decreased from 105.1 ± 15.9 to 97.4 ± 13.8 mL/min/1.73 m2 and the prevalence of mildly reduced renal function (eGFR ≤ 60–

Aim: Early intervention before the progression of chronic kidney disease (CKD) is essential to prevent end-stage renal disease (ESRD) and cardiovascular complications. This study evaluated the correlation between metabolic and lifestyle-related factors and the decline of estimated glomerular filtration rate (eGFR) over 1 year in a Japanese population without CKD. Methods: Subjects who received two consecutive annual health checkups from 2013 to 2015 were involved. Factors associated with eGFR decline were identified using multiple regression models. Results: A total of 2531 subjects aged 58.9 ± 11.7 years old were included in this study. Baseline levels of HDL-C and ApoA1 correlated with the eGFR decline over 1 year defined as eGFR reduction rate of 15% or more and/or eGFR at the next year < 60 ml/min/m2 (odds ratio (OR) 0.87 (per 10 mg/dl); 95% CI, 0.80–0.94; p = 0.0012, 0.90 (per 10 mg/dl); 0.86–0.96; p = 0.0004, respectively). A U-shaped relationship between the eGFR decline and HDL-C or ApoA1 levels was not observed in non-CKD population of this study. Metabolic syndrome was significantly associated with eGFR decline (OR 1.32; 1.04–1.67; p = 0.0205), although obesity-related factors did not show a significant correlation with eGFR decline over 1 year. Conclusion: Low HDL-C and ApoA1 levels significantly correlated with eGFR decline in a short period of 1 year. Metabolic syndrome also showed a significant association with eGFR decline. This study suggests the importance of hypertension and low HDL-C in the metabolic syndrome effect on eGFR decline rather than obesity in non-CKD population.

Low serum 25-hydroxyvitamin D (25(OH)D) levels are implicated as a risk factor for hip and spine fractures. Studies of the relation between 25(OH)D levels and fractures have primarily involved elderly osteoporosis patients or patients with fractures; however, the serum 25(OH)D and parathyroid hormone (PTH) status in younger adult populations remains largely unknown. We evaluated serum 25(OH)D and intact PTH levels in 411 women aged 39-64 years who were not receiving medication for osteoporosis or other bone diseases. Serum 25(OH)D levels were positively correlated with age (P = 0.019), whereas intact PTH levels were inversely correlated with 25(OH)D levels (P < 0.001). Thus, low vitamin D levels with high intact PTH levels were more common in younger than in older women. Our data show that serum 25(OH)D insufficiency could be a more serious concern in the younger population than had been previously anticipated. Because serum 25(OH)D insufficiency is reportedly a risk factor for hip and spine fracture, the number of fracture patients could increase in the future, suggesting that we may need to correct the serum vitamin D/intact PTH status to prevent future osteoporosis.

To assess associations between neonatal intensive care unit (NICU)-level patent ductus arteriosus (PDA) treatment rates (pharmacologic or surgical) and neonatal outcomes.This cohort study included infants born at 24-28 weeks of gestation and birth weight1500 g in 2007-2015 in NICUs caring for ≥100 eligible infants in 6 countries. The ratio of observed/expected (O/E) PDA treatment rates was derived for each NICU by estimating the expected rate using a logistic regression model adjusted for potential confounders and network. The primary composite outcome was death or severe neurologic injury (grades III-IV intraventricular hemorrhage or periventricular leukomalacia). The associations between the NICU-level O/E PDA treatment ratio and neonatal outcomes were assessed using linear regression analyses including a quadratic effect (a square term) of the O/E PDA treatment ratio.From 139 NICUs, 39 096 infants were included. The overall PDA treatment rate was 45% in the cohort (13%-77% by NICU) and the O/E PDA treatment ratio ranged from 0.30 to 2.14. The relationship between the O/E PDA treatment ratio and primary composite outcome was U-shaped, with the nadir at a ratio of 1.13 and a significant quadratic effect (P.001). U-shaped relationships were also identified with death, severe neurologic injury, and necrotizing enterocolitis.Both low and high PDA treatment rates were associated with death or severe neurologic injury, whereas a moderate approach was associated with optimal outcomes.

Summary: Nicotinamide adenine dinucleotide (NAD+) metabolism plays a critical role in kidneys. We previously reported that decreased secretion of a NAD+ precursor, nicotinamide mononucleotide (NMN), from proximal tubules (PTs) can trigger diabetic albuminuria. In the present study, we investigated the role of NMN-producing enzyme nicotinamide phosphoribosyltransferase (Nampt) in diabetic nephropathy. The expression of Nampt in PTs was downregulated in streptozotocin (STZ)-treated diabetic mice when they exhibited albuminuria. This albuminuria was ameliorated in PT-specific Nampt-overexpressing transgenic (TG) mice. PT-specific Nampt-conditional knockout (Nampt CKO) mice exhibited TBM thickening and collagen deposition, which were associated with the upregulation of the profibrogenic gene TIMP-1. Nampt CKO mice also exhibited the downregulation of sirtuins, particularly in Sirt6. PT-specific Sirt6-knockout mice exhibited enhanced fibrotic phenotype resembling that of Nampt CKO mice with increased Timp1 expression. In conclusion, the Nampt-Sirt6 axis in PTs serves as a key player in fibrogenic extracellular matrix remodeling in diabetic nephropathy. : Muraoka et al. reveal that the Nampt-Sirt6 axis in proximal tubules serves as a key player in fibrogenic extracellular matrix remodeling in diabetic nephropathy. Keywords: NAD, Nampt, Sirt6, metabo-fibrosis, NMN, TBM thickening, diabetic nephropathy

Sleep is a physiological process not only for the rest of the body but also for several brain functions such as mood, memory, and consciousness. Nevertheless, the nature and functions of sleep remain largely unknown due to its extremely complicated nature and lack of optimized technology for the experiments. Here we review the recent progress in the biology of the mammalian sleep, which covers a wide range of research areas: the basic knowledge about sleep, the physiology of cerebral cortex in sleeping animals, the detailed morphological features of thalamocortical networks, the mechanisms underlying fluctuating activity of autonomic nervous systems during rapid eye movement sleep, the cutting-edge technology of tissue clearing for visualization of the whole brain, the ketogenesis-mediated homeostatic regulation of sleep, and the forward genetic approach for identification of novel genes involved in sleep. We hope this multifaceted review will be helpful for researchers who are interested in the biology of sleep.

Background The lipodystrophy-like phenotype has been suggested in early chronic kidney disease (CKD). It includes adipose tissue atrophy, systemic insulin resistance (IR), dyslipidemia and ectopic lipid accumulation. To elucidate its pathogenesis, we investigated the role of two uremic toxins that affect insulin sensitivity: an endogenous nitric oxide synthase inhibitor, and asymmetric dimethylarginine (ADMA) and indoxyl sulfate (IS). Methods Six-week-old Sprague-Dawley rats were rendered CKD by subtotal nephrectomy (Nx) and compared with sham-operated rats. Cultured 3T3-L1 fibroblasts were differentiated into mature adipocytes with or without ADMA. Transgenic (Tg) mice overexpressing each isoform of ADMA degrading enzyme, dimethylarginine dimethylaminohydrolase 1 (DDAH1) and DDAH2 were subject to Nx and their phenotypes were investigated. Results In Nx rats, IR was evident and insulin stimulation failed to activate insulin signaling in adipose tissues. Adipose tissue weight, adipocyte size and adipocyte differentiation marker expressions decreased as a consequence of IR in Nx. Tissue lipid content in the liver and muscle increased in Nx rats. Tissue levels of ADMA, IS and oxidative stress increased in the adipose tissue of Nx rats. Both DDAH1 and DDAH2 expressions decreased, and a putative IS receptor, aryl hydrocarbon receptor, expression increased in the adipose tissue of Nx rats. ADMA inhibited adipocyte differentiation, triglyceride accumulation and insulin signaling, which were reversed by pretreatment with cGMP. In each type of Tg mice overexpressing DDAH1 or DDAH2, all lipodystrophy-like phenotypes induced by Nx were reversed. Conclusions In mild CKD, dysregulation of the ADMA/DDAH pathway in adipose tissue triggers lipodystrophy-like phenotype changes, including ectopic fat depositions.

Background The role of gut microbiota in the progression of chronic kidney disease (CKD) has not been fully elucidated. Methods Renal failure was induced in 6-week-old spontaneously hypertensive rats by 5/6 nephrectomy (Nx). We analyzed the gut microbiota population to identify the relevant species potentially involved in inducing renal damage. Human colon Caco-2 cells were used to delineate the mechanism involved in the molecular changes in the gut of Nx rats. Results Nx rats showed an increase in Bacteroides (Bact) and a decrease in Lactobacillus (Lact) species compared with sham-operated rats. Lact, but not Bact, populations were significantly associated with urinary protein excretion. Treatment of Nx rats with 1 × 10(10) CFU/kg/day Lact ameliorated increased urinary protein excretion and higher serum levels of the uremic toxins, indoxyl sulfate and p-cresyl sulfate, and serum urea nitrogen levels. Lact also attenuated systemic inflammation in Nx rats, as evaluated by serum lipopolysaccharide, interleukin-6 and C-reactive protein levels. Histologically, renal sclerosis in Nx rats was restored by Lact treatment. A reduction in the expression of tight junction proteins and the Toll-like receptor 2 (TLR2), a putative Lact receptor, in the colons of Nx rats were mitigated by Lact. Treatment of Caco-2 cells with indole downregulated tight junction protein expression, which was abolished by exposure to Lact. The effects of Lact were reversed by treatment with OxPAPC, a TLR inhibitor. Similarly, the increase in the permeability of the Caco-2 cell monolayer was reversed by the administration of Lact. Lact upregulated TLR2 expression in Caco-2 cells. Lact also attenuated the increase in serum indoxyl sulfate and urea levels and urinary protein excretion in Nx rats even in the pseudogerm-free environment. Conclusions Lact supplementation mitigated the systemic inflammation and proteinuria associated with renal failure, suggesting that in the gut microbiota, Lact plays a protective role against the progression of CKD.

In this study, we examined the association between chronic kidney disease (CKD) and insulin resistance. In a patient cohort with nondiabetic stages 2-5 CKD, estimated glomerular filtration rate (eGFR) was negatively correlated and the plasma aldosterone concentration was independently associated with the homeostasis model assessment of insulin resistance. Treatment with the mineralocorticoid receptor blocker spironolactone ameliorated insulin resistance in patients, and impaired glucose tolerance was partially reversed in fifth/sixth nephrectomized rats. In these rats, insulin-induced signal transduction was attenuated, especially in the adipose tissue. In the adipose tissue of nephrectomized rats, nuclear mineralocorticoid receptor expression, expression of the mineralocorticoid receptor target molecule SGK-1, tissue aldosterone content, and expression of the aldosterone-producing enzyme CYP11B2 increased. Mineralocorticoid receptor activation in the adipose tissue was reversed by spironolactone. In the adipose tissue of nephrectomized rats, asymmetric dimethylarginine (ADMA; an uremic substance linking uremia and insulin resistance) increased, the expression of the ADMA-degrading enzymes DDAH1 and DDAH2 decreased, and the oxidative stress increased. All of these changes were reversed by spironolactone. In mature adipocytes, aldosterone downregulated both DDAH1 and DDAH2 expression, and ADMA inhibited the insulin-induced cellular signaling. Thus, activation of mineralocorticoid receptor and resultant ADMA accumulation in adipose tissue has, in part, a relevant role in the development of insulin resistance in CKD.

Narcolepsy-cataplexy is a debilitating disorder of sleep/wakefulness caused by a loss of orexin-producing neurons in the lateroposterior hypothalamus. Genetic or pharmacologic orexin replacement ameliorates symptoms in mouse models of narcolepsy-cataplexy. We have recently discovered a potent, nonpeptide OX2R-selective agonist, YNT-185. This study validates the pharmacological activity of this compound in OX2R-transfected cells and in OX2R-expressing neurons in brain slice preparations. Intraperitoneal, and intracerebroventricular, administration of YNT-185 suppressed cataplexy-like episodes in orexin knockout and orexin neuron-ablated mice, but not in orexin receptor-deficient mice. Peripherally administered YNT-185 also promotes wakefulness without affecting body temperature in wild-type mice. Further, there was no immediate rebound sleep after YNT-185 administration in active phase in wild-type and orexin-deficient mice. No desensitization was observed after repeated administration of YNT-185 with respect to the suppression of cataplexy-like episodes. These results provide a proof-of-concept for a mechanistic therapy of narcolepsy-cataplexy by OX2R agonists.

The involvement of tissue ischemia in obesity-induced kidney injury remains to be elucidated. Compared with low fat diet (LFD)-mice, high fat diet (HFD)-fed mice became obese with tubular enlargement, glomerulomegaly and peritubular capillary rarefaction, and exhibited both tubular and glomerular damages. In HFD-fed mice, despite the increase in renal pimonidazole-positive areas, the expressions of the hypoxia-responsive genes such as Prolyl-hydroxylase PHD2, a dominant oxygen sensor, and VEGFA were unchanged indicating impaired hypoxic response. Tamoxifen inducible proximal tubules (PT)-specific Phd2 knockout (Phd2-cKO) mice and their littermate control mice (Control) were created and fed HFD or LFD. Control mice on HFD (Control HFD) exhibited renal damages and renal ischemia with impaired hypoxic response compared with those on LFD. After tamoxifen treatment, HFD-fed knockout mice (Phd2-cKO HFD) had increased peritubular capillaries and the increased expressions of hypoxia responsive genes compared to Control HFD mice. Phd2-cKO HFD also exhibited the mitigation of tubular damages, albuminuria and glomerulomegaly. In human PT cells, the increased expressions of hypoxia-inducible genes in hypoxic condition were attenuated by free fatty acids. Thus, aberrant hypoxic responses due to dysfunction of PHD2 caused both glomerular and tubular damages in HFD-induced obese mice. Phd2-inactivation provides a novel strategy against obesity-induced kidney injury.

Sleep is a behavior conserved from invertebrates to vertebrates, and tightly regulated in a homeostatic manner. The molecular and cellular mechanism determining the amount of rapid eye movement sleep (REMS) and non-REMS (NREMS) remains unknown. Here we identified two dominant mutations affecting sleep/wakefulness through an electroencephalogram/electromyogram-based screening of randomly mutagenized mice. A splicing mutation of the Sik3 protein kinase gene causes a profound decrease in total wake time, due to an increase in inherent sleep need. Sleep deprivation affects regulatory-site phosphorylation of the kinase. Sik3 orthologues regulate sleep also in fruit flies and roundworms. A missense mutation of the leak cation channel NALCN reduces the total amount and episode duration of REMS, apparently by increasing the excitability of REMS-inhibiting neurons. Our results substantiate the utility of forward genetic approach for sleep behaviors in mice, demonstrating the role of SIK3 and NALCN in regulating the amount of NREMS and REMS, respectively.

OBJECTIVE To compare rates of a composite outcome of mortality or major morbidity in very-preterm/very low birth weight infants between 8 members of the International Network for Evaluating Outcomes. STUDY DESIGN We included 58 004 infants born weighing

Aim The waist circumference (WC) cut-off values in the diagnostic criteria of metabolic syndrome (MetS) established in Japan (Japanese criteria) differ from those established by the International Diabetes Federation (IDF) for Asians (IDF criteria). Methods To settle this contradiction, a cross-sectional study of Japanese aged 20-65 years was performed. After excluding subjects suffering from significant diseases other than those constituting MetS, excessive drinkers, and regular smokers, 835 males and 1,304 females were examined. WC was measured at the umbilical level (UWC) and midway between the ribs and iliac crest (MWC) according to both criteria in each subject. Results Upper limits of reference intervals of MWC estimated in subjects free from MetS were 84.6 and 84.3 cm in older (40-65 years) and younger (20-39) males, and 78.4 and 70.5 cm in older and younger females, respectively; those of UWC were 86.4, 86.2, 87.9 and 78.9 cm, respectively. Receiver operating characteristic (ROC) curves for MWC to predict UWC reproduced the relationships of the two types of cut-off values in each population. Conclusion WC cut-off values in the Japanese and IDF criteria have the potential to be valid as cut-off values of UWC and MWC in Japanese, respectively. Their difference can be explained by the variation in the WC definition, and they can stand together without inconsistency. Acceptance of the recently prevailing view that the WC standard in IDF for Asian males should be 85 cm and the introduction of new criteria for younger females in consideration of their generation differences in both criteria could facilitate their higher compatibility.

Objective: Peroxisome proliferator–activated receptor (PPAR)-γ ligand, pioglitazone (PIO), is reported to induce edema especially in postmenopausal women. The aim of this study was to elucidate the mechanism for PIO-induced sodium retention and to discover the therapeutic strategy for the PIO-induced changes in renal sodium handling. Methods and Procedures: Zucker obese rats were ovariectomized and were given PIO for 8 weeks. Renal sodium excretion and renal expressions of several enzymes that generate natriuretic substances were examined. Results: Sodium excretion was decreased in ovariectomized (OVX) rats that were given PIO when compared with OVX rats that were not. Urinary nitrites/nitrates excretion was decreased in OVX rats, but was restored by PIO. The expressions of nitric oxide synthases (NOSs) and cyclooxygenases-1/2 (COX-1/2) were unaltered. Similarly, the expression of epithelial sodium channels (ENaC), identified as a PPAR-γ-regulated gene product, was unaffected. In contrast, the expression of cytochrome P450 4A (CYP4A) was increased in OVX rats, and was downregulated by PIO. Co-treatment of OVX rats with PIO and PPAR-α ligand, fenofibrate, a putative inducer of CYP4A, restored not only the impaired sodium excretion but also the downregulated CYP4A expression. Discussion: PIO-induced sodium retention is specific in female OVX rats. Ovariectomy decreases renal NO production, but upregulates renal CYP4A expression to compensate for renal sodium balance. In this setting, PIO downregulates CYP4A, leading to sodium retention. Furthermore, PPAR-α ligands can provide a novel strategy for preventing the PIO-induced sodium retention.

Type 2 diabetes carries an unequivocal risk for cardiovascular disease.[1][1] Patients with diabetes have the same risk for future cardiovascular events as survivors of myocardial infarction.[2][2] Morbidity and mortality in diabetes is largely driven by atherosclerotic complications. Just the

Cardiovascular events are accelerated in chronic kidney disease (CKD). Although deranged nitric oxide (NO) pathways and asymmetric dimethylarginine (ADMA) cause endothelial dysfunction, no direct evidence for coronary artery endothelial dysfunction in CKD has been documented. CKD was induced in male dogs by heminephrectomy (1/2Nx) or five-sixths nephrectomy (5/6Nx). After 4 wk, renal ablation reduced GFR (control 76 [54 to 85]; 1/2Nx 38 [29 to 47]; 5/6Nx 15 [12 to 46] ml/min) and elevated plasma ADMA (control 1.88 [1.68 to 2.54]; 1/2Nx 2.51 [2.11 to 3.55]; 5/6Nx 3.84 [2.16 to 3.95] micromol/L). Coronary circulatory responses to acetylcholine revealed marked increases in coronary blood flow in control group (83 +/- 17% increment) but blunted responses in 1/2Nx (34 +/- 8% increment) and 5/6Nx (20 +/- 4% increment). The acetylcholine-induced changes in epicardial arteriolar diameter, using needle-lens probe charge-coupled device videomicroscopy, showed similar results. The responsiveness to sodium nitroprusside did not differ among three groups. Plasma nitrite/nitrate levels decreased in 1/2Nx and 5/6Nx, and the mRNA expressions of dimethylarginine dimethylaminohydrolase-II (DDAH-II), ADMA-degrading enzyme, and endothelial NO synthase (eNOS) in coronary arteries were downregulated in 1/2Nx and 5/6Nx. Finally, 4-wk treatment with all-trans retinoic acid restored the impaired endothelium-dependent vasodilation and reversed the expression of eNOS but not DDAH-II. Coronary endothelial function is impaired in the early stage of CKD. The dysfunction is attributed to the downregulation of eNOS and/or DDAH-II in coronary arteries. Furthermore, the manipulation of NO pathways may constitute a therapeutic strategy for the prevention of coronary dysfunction in CKD.

We have recently published that tubular epithelial cells affect the podocyte epigenome though nicotinic acid metabolism in diabetic nephropathy (DN), and we have named this relationship "proximal tubule-podocyte communication". In this review, we describe this novel mechanism in the early stage of DN, focusing on the function of renal tubular Sirt1 and Sirt1-related nicotinic acid metabolism. Mainly, we discuss the following three findings. First, we described the details of proximal tubule-podocyte communication. Second, we explained how Sirt1 regulates albuminuria via epigenetic mechanisms. This means that repeated high glucose stress triggers the initial changes in proximal tubules, which lead to the epigenetically irreversible glomerular damages. However, proximal tubular Sirt1 overexpression can rescue these changes. Our previous data indicated that the decrease in Sirt1 expression in proximal tubules caused the reduction in glomerular Sirt1 and the subsequent increase in glomerular Claudin-1. It seemed plausible that some humoral mediator is released from proximal tubules, migrates to podocytes and glomeruli, and affects Sirt1 expression in podocytes. Third, we mentioned a mediator connecting this communication, nicotinamide mononucleotide (NMN). We suggest the potential of Sirt1 or NMN as not only a therapeutic target but also as a prognostic marker of very early stage DN.

Plasma-oxidized (ox) low-density lipoprotein (LDL) is an atherogenic lipoprotein. The distribution of ox-LDL in plasma LDL subfractions and the effect of statins on this distribution have not been investigated in detail.We examined the distribution of cholesterol and ox-LDL in 3 ultracentrifugally separated plasma LDL subfractions and investigated the effects of a statin, rosuvastatin, on the levels of these lipoproteins.Thirty-one polygenic hypercholesterolemic subjects were included in this study. Levels of cholesterol and ox-LDL in 3 plasma LDL subfractions and plasma levels of remnant-like particle cholesterol, ox-LDL, and adiponectin were measured after 0, 3, 6, and 12 months of treatment with rosuvastatin. Sequential ultracentrifugation was performed to subfractionate plasma lipoproteins.The mean daily dose of rosuvastatin over the 12 months of treatment was 2.9 ± 1.0 mg (mean ± standard deviation). The cholesterol subfraction distribution was 43 ± 10% as low-density LDL, 46 ± 8% as medium-density LDL, and 13 ± 5% as high-density LDL. Similarly, the distribution of ox-LDL was 31 ± 10% as low-density LDL, 48 ± 7% as medium-density LDL, and 22 ± 8% as high-density LDL. After 12 months of treatment with rosuvastatin, the level of cholesterol was significantly reduced in all 3 subfractions (P.0001), as was the level of ox-LDL (P.0001). Furthermore, the plasma cholesterol level in high-density lipoprotein2 increased significantly.The distribution of ox-LDL in plasma LDL subfractions was more skewed toward the denser subfractions, compared with cholesterol. Rosuvastatin treatment significantly reduced plasma levels of cholesterol and ox-LDL in all LDL subfractions.

Objectives— Dimethylarginie dimethylaminohydrolase (DDAH) is a degrading enzyme for asymmetrical dimethylarginine, an endogenous NO synthase inhibitor. The molecular mechanism for DDAH-induced vascular endothelial growth factor (VEGF) expression was examined. Methods and Results— Although the transfection of expression vectors for 2 isoforms of DDAH, DDAH1, or DDAH2 increased DDAH activity in bovine aortic endothelial cells and human umbilical vein endothelial cells, expression and secretion of VEGF were increased only in DDAH2-transfected cells. Knocking down the DDAH2 gene reduced VEGF production, and DDAH2 overexpression enhanced both proliferation and migration of endothelial cells. The VEGF promoter activity was increased by DDAH2 transfection, which was not blocked by an NO synthase (NOS) inhibitor but required the Sp1 sites. DDAH2 overexpression increased nuclear protein levels bound to Sp1 oligonucleotides in endothelial cells. Sp1 small interfering RNA blocked DDAH2-induced upregulation of VEGF. DDAH2 transfection increased nuclear and threonine-phosphorylation levels of Sp1 in a protein kinase A (PKA)–dependent manner. Protein–protein interaction between DDAH2 and PKA was enhanced in DDAH2-transfected cells. Conclusions— DDAH2 upregulated the expression of VEGF through Sp1-dependent and NO/NOS system-independent promoter activation. DDAH2-increased Sp1 DNA binding activity was PKA dependent. These mechanisms may provide a novel therapeutic strategy for VEGF-related vasculopathies such as atherosclerosis.

Rho/Rho-kinase plays an important role not only in the vasoconstrictor mechanism but also in cellular morphology, motility, adhesion, and proliferation. This pathway also serves to modulate the structure and function of various kidney cells including tubular epithelial cells, mesangial cells, and podocytes. The inhibition of the Rho/Rho-kinase pathway elicits marked increases in renal blood flow in vivo and dilates both afferent and efferent arterioles preconstricted by angiotensin II in vitro. In renal injury, intrarenal angiotensin II is reported to be activated, which subsequently would upregulate the Rho-kinase pathway. A selective Rho-kinase inhibitor, fasudil, has recently been shown to improve renal damage resulting from hypertensive glomerulosclerosis, unilateral ureteral obstruction (for interstitial renal fibrosis) and subtotal nephrectomy. Of interest, fasudil upregulated the expression of p27kip1, a cyclin-dependent kinase inhibitor, and increased the p27kip1 immuno-positive cells in both glomeruli and tubulointerstitium with the use of immunohistochemistry. Collectively, the Rho-kinase pathway is involved in the pathogenesis of renal injury. Clinical application of this type of therapy however awaits further investigations. Keywords:: Rho-kinase, renal hemodynamics, fasudil, renal injury, p27kip1

Background and aims We previously demonstrated that acetylcholine elicited nitric oxide-dependent sustained and endothelium-derived hyperpolarizing factor (EDHF)-dependent transient dilation of afferent arterioles. The present study examined whether free radicals interacted with nitric oxide-dependent and EDHF-dependent vasodilator mechanisms in renal microvessels of salt-sensitive hypertension, using the isolated perfused hydronephrotic kidney. Methods and results Following the pretreatment with indomethacin (100 micromol/L) with or without nitro- l-arginine methylester (100 micromol/L), the effect of acetylcholine on noradrenaline (0.3 micromol/L)-induced constriction was evaluated in kidneys from Dahl salt-sensitive and salt-resistant rats. Although acetylcholine (0.01-10 micromol/L) caused dose-dependent and sustained vasodilation of afferent arterioles, attenuated dilation was observed in Dahl salt-sensitive rats, compared with that in salt-resistant rats (58 +/- 4 vs 101 +/- 11% reversal at 10 micromol/L acetylcholine). In the presence of nitro- l-arginine methylester, acetylcholine elicited only transient dilation, with vasodilator response blunted in Dahl salt-sensitive rats (64 +/- 4 vs 100 +/- 9% reversal at 10 micromol/L acetylcholine). Furthermore, chronic (8-10 weeks) treatment with tempol caused partial restoration of acetylcholine (10 micromol/L)-induced sustained arteriolar dilation (71 +/- 3% reversal), but complete reversal of transient dilation (92 +/- 4% reversal). Finally, acute treatment with tempol not only improved the sustained component of the acetylcholine-induced dilation but also restored the impaired responsiveness of transient dilation in Dahl salt-sensitive rats. Conclusion Both sustained (nitric oxide-mediated) and transient (EDHF-mediated) components of acetylcholine-induced afferent arteriolar dilation were attenuated in Dahl salt-sensitive rats, which was attributed, in part, to enhanced free radical activity. A reversal of the sustained and transient vasodilation by the acute tempol treatment suggests possible interaction between free radicals and EDHF as well as increased bioavailability of nitric oxide.

We examined the role of free radicals in renal microvascular tone induced by various vasoactive stimuli. Isolated perfused rat hydronephrotic kidneys were used for direct visualization of renal microcirculation. The effect of tempol on angiotensin II-, norepinephrine-, KCl-, and pressure-induced afferent arteriolar constriction was evaluated. Under angiotensin II-induced constriction, tempol (3 mmol/L) caused 57 +/- 8% dilation of afferent arterioles. In contrast, tempol elicited only 38 +/- 8% and 26 +/- 9% dilation of norepinephrine- and KCl-induced constriction. Similarly, myogenic response induced by elevating renal arterial pressure from 80 to 180 mmHg was resistant to the vasodilator action of tempol (22 +/- 7% inhibition). Furthermore, tempol failed to reverse nitro-L-arginine methylester-induced afferent constriction, nor had vasodilator effect on the angiotensin II-induced constriction in the presence of nitro-L-arginine methylester. In contrast, nitroprusside elicited marked vasodilation of angiotensin II- (97 +/- 5% reversal) and norepinephrine-induced afferent constriction (89 +/- 6% reversal), but had less effect on KCl- (46 +/- 8% reversal) and pressure-induced constriction (26 +/- 9% reversal). These different actions were also observed when polyethylene-glycolated superoxide dismutase was used as an antioxidant. In conclusion, the role of free radicals in afferent arteriolar tone varies, depending on the underlying vasoconstrictor stimuli, with greater contribution of free radicals to angiotensin II-induced constriction. The heterogeneity in the responsiveness to free radical scavengers is attributed to both magnitude of free radicals produced and sensitivity of the underlying vasoconstrictors to nitric oxide.

Although nifedipine and other conventional calcium antagonists elicit preferential vasodilation of renal afferent arterioles, we demonstrate that mibefradil and nickel, T-type calcium channel blockers, reverse the angiotensin II-induced constriction of both afferent and efferent arterioles. Since the angiotensin II-induced vasoconstriction involves inositol trisphosphate (IP3)-induced calcium release from the sarcoplasmic reticulum in the afferent arteriole, and both IP3- and protein kinase C (PKC)-mediated pathways in the efferent arteriole, we investigated the cellular mechanism for the mibefradil-induced dilation of angiotensin II-constricted renal arterioles, using the isolated perfused hydronephrotic rat kidney. Mibefradil caused a dose-dependent dilation of angiotensin II-constricted afferent and efferent arterioles, with 88 ± 9% and 74 ± 10% reversal observed at 1 μmol/L, respectively. The blockade of PKC by staurosporine did not alter the mibefradil-induced vasodilator responses of either arterioles (P > 0.5). In contrast, the pretreatment with thapsigargin, which predominantly blocked the IP3-mediated intracellular calcium release, prevented the afferent arteriolar constrictor response to angiotensin II, but caused a significant constriction of efferent arterioles. The subsequent addition of mibefradil had no effect on the efferent arteriolar diameter. Furthermore, the efferent arteriolar constriction induced by direct PKC activation by phorbol myristate acetate was refractory to mibefradil, but completely reversed by LOE908, a nonselective cation channel blocker. In summary, mibefradil markedly dilates the angiotensin II-induced renal arteriolar constriction; the action of mibefradil is most likely mediated by the inhibition of the IP3-mediated pathway, but the inhibitory action on the PKC pathway appears modest.

We examined the role of Rho/Rho-kinase in renal afferent and efferent arteriolar tone induced by angiotensin (Ang) II, KCl and elevated renal arterial pressure (from 80 to 180 mm Hg), using isolated perfused rat hydronephrotic kidney. In the condition with no vasoconstrictor stimuli, Y-27632, a Rho-kinase inhibitor, dilated only afferent (from 11.6 ± 0.4 to 14.1 ± 0.5 µm) but not efferent arterioles (from 11.6 ± 0.2 to 12.6 ± 0.7 µm) at 10–5 mol/l. During renal vasoconstriction by Ang II, Y-27632 restored the afferent arteriolar constriction (141 ± 10% reversal at 10–5 mol/l), whereas the ability of Y-27632 to inhibit the Ang II-induced efferent arteriolar constriction was diminished (73 ± 7% reversal). A similar action was observed with fasudil, another Rho-kinase inhibitor. Furthermore, Y-27632 impaired myogenic afferent arteriolar constriction, with 117 ± 17% inhibition at 10–5 mol/l. The inhibition by Y-27632 of the myogenic vasoconstriction was almost the same as that of the Ang II-induced tone of this vessel type. However, Y-27632 had a modest effect on KCl-induced vasoconstriction of afferent arterioles. In conclusion, the present study demonstrates a predominant role of Rho/Rho-kinase in mediating the basal and Ang II-induced tone of afferent, but not efferent, arterioles. Furthermore, the role of Rho/Rho-kinase in afferent arteriolar constriction differs, with a substantial contribution to Ang II-induced and myogenic constriction but a minimal role in depolarization-induced constriction. Since Ang II-induced, KCl-induced and myogenic constriction of afferent arterioles require calcium entry through voltage-dependent calcium channels, the interaction between Rho/Rho-kinase and the calcium entry pathway may determine the afferent arteriolar tone induced by these stimuli.

It has becoming clear that angiotensin receptor blockers (ARBs) show varying levels of angiotensin II type 1 (AT1) receptor blocking activity. Although the duration of activity and the efficacy on blood pressure of ARB are reported to vary, depending on the agents used, it has not been examined whether the effects on proteinuria and urinary nitrite/nitrate (NOx) excretion differ in hypertensive patients with chronic renal disease. In the present study, patients with hypertension (140 and/or 90 mmHg) and chronic renal disease (proteinuria0.5g/day; serum creatinine265 micromol/l or creatinine clearance30 ml/min/1.72 m2) were randomly assigned to perindopril- (n = 15), trandolapril- (n = 15), candesartan- (n = 17), and losartan-treated groups (n = 15), and were followed up for 96 weeks. All agents decreased blood pressure to the same level, and none of them had any effect on creatinine clearance. Candesartan, perindopril, and trandolapril reduced proteinuria markedly (from 3.0 +/- 0.6 to 1.8 +/- 0.5 g/day, 2.7 +/- 0.5 to 1.6 +/- 0.4 g/day, and 2.7 +/- 0.5 to 1.7 +/- 0.4 g/day, respectively) at 12 weeks, and the beneficial effect persisted throughout the study. The effect of losartan, however, diminished over the study period. Whereas perindopril, trandolapril, and candesartan markedly increased urinary NOx excretion (from 257 +/- 23 to 1,011 +/- 150 micromol/day, 265 +/- 70 to 986 +/- 130 micromol/day, and 260 +/- 62 to 967 +/- 67 micromol/day at 12 weeks, respectively), a relatively blunted increase was observed with losartan (from 309 +/- 42 to 596 +/- 64 micromol/day). In conclusion, renal action of ARB varies, with relatively less proteinuria-sparing, as well as NOx-enhancing, effects observed with candesartan showing the greatest reduction of proteinuria and greatest enhancement of NOx. Furthermore, renal nitric oxide may contribute to the renal protective action of these agents when administered to patients with chronic renal disease.

末期慢性腎不全では出血傾向が出現し, その機序として腎不全に伴う体内蓄積物の関与が示唆されている. 一方, 大多数の例で降圧薬が処方されているが, その関与を検討した報告はない. 本研究は, 内シャント作成目的で入院した末期慢性腎不全患者135例に対し, 出血時間と降圧薬との関連を検討した. 降圧薬服用者では90.4% (28例) に出血時間の延長がみられたが, 非服用群 (n=13) では全例出血時間は正常であった. 出血時間とBUN, 血清クレアチニンならびに拡張期血圧とは軽度の正相関がみられ (各々, 0.19, 0.19, 0.26), 血小板数とは負の相関がみられた (-0.16). カルシウム拮抗薬服用群 (n=111) では, 23.4% (26例) に出血時間の延長がみられたのに対し, 非服用群では8.3% (2例) に観察されたのみであった. 一方, α遮断薬ではこのような影響は認めなかった. αβ遮断薬に関しても, 出血時間の延長は服薬群 (27.7%) が非服薬群 (19.7%) よりやや多かったが, カルシウム拮抗薬の併用がαβ遮断薬服用群 (100%) で非服用群 (82.6%) より多かった. さらに, カルシウム拮抗薬服用群のうち, 出血時間の延長している9例に対し, 7-10日間服薬を中止し再度出血時間を測定したところ, 著明な改善がみられた (11.4±1.0から5.9±1.0分). 一方, 服薬を継続し同間隔で測定した群では出血時間の変化はみられなかった (12.2±1.1から10.3±1.3分, n=7). 一方, カルシウム拮抗薬服薬群において, 出血時間の延長と臨床的出血傾向とは関連性を認めなかった. 以上の結果より, 透析導入期末期慢性腎不全では, 出血時間の延長がみられ, その機序として降圧薬とりわけカルシウム拮抗薬の関与が考えられた. しかしながら, この異常が臨床的出血傾向を助長する可能性は確認されなかった.

Background: Both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) are established as important factors determining the vascular tone. The relative contribution of these factors to the renal microvascular tone, however, has not been delineated. Methods: Isolated perfused hydronephrotic rat kidneys were used to characterize the relative role of NO and EDHF in mediating the tone of interlobular arteries (ILA) and afferent arterioles (AFF). Results: During the norepinephrine constriction, acetylcholine (ACH, 1 µmol/l) induced a sustained vasodilation of ILA (90 ± 9% reversal) and AFF (117 ± 13% reversal). In the presence of nitro-L-arginine methylester (LNAME), the ACH-induced vasodilation of ILA and AFF was converted to transient dilation, with only 53 ± 7 and 32 ± 7% reversal observed 10 min after 1 µmol/l ACH (i.e sustained phase). In contrast, LNAME had no effect on the initial phase of ACH-induced dilation. In the presence of apamin + charybdotoxin, the initial vasodilator response to ACH (1 µmol/l) was diminished (ILA, from 108 ± 8 to 46 ± 9%; AFF, from 108 ± 14 to 58 ± 8%), whereas no impairment was observed in sustained phases. Furthermore, the magnitude of the vasoconstriction caused by LNAME was greater at smaller vessel segments. Finally, the LNAME-induced inhibition of the sustained phase of ACH-induced vasodilation was greater as the vessel diameter decreased. Conclusions: That the relative contribution of NO and EDHF differs, with a greater role of NO in the basal tone and ACH-induced vasodilation at smaller vascular segments of ILA and AFF.

Renal afferent arterioles (AFF) regulate glomerular capillary pressure through two main mechanisms: the myogenic response (MYO) and tubuloglomerular feedback (TGF). Because Rho-kinase and nitric oxide synthase (NOS) are established factors that modulate vascular tone, we examined the role of these factors in pressure-induced AFF tone in Wistar-Kyoto rats and in spontaneously hypertensive rats (SHR) using an intravital CCD camera. Elevated renal perfusion pressure elicited marked AFF constriction that was partially inhibited by gadolinium, furosemide and fasudil, which inhibit MYO, TGF and Rho-kinase, respectively; however, this AFF constriction was completely blocked by combined treatment with fasudil+gadolinium or fasudil+furosemide. S-methyl-L-thiocitrulline (SMTC) partially reversed the fasudil-induced inhibition of TGF-mediated, but not that of MYO-mediated, AFF constriction. In SHR, the pressure-induced AFF response was enhanced, and MYO- and TGF-induced constriction were exaggerated. In the presence of gadolinium, SMTC partially mitigated the fasudil-induced inhibition of TGF-mediated AFF constriction. Immunoblot analyses demonstrated that both Rho-kinase activity and neuronal NOS were augmented in SHR kidneys. In conclusion, Rho-kinase contributes to MYO- and TGF-mediated AFF responses, and these responses are enhanced in SHR. Furthermore, neuronal NOS-induced nitric oxide modulates the TGF mechanism. This mechanism constitutes a target for Rho-kinase in TGF-mediated AFF constriction.

We report a case with portal systemic encephalopathy who presented with dressing and constructional apraxia and subtle weakness of the left hand. We initially suspected a cerebrovascular attack in the right cerebral hemisphere, but brain T1-weighted magnetic resonance (MR) imaging revealed high intensity in the basal ganglia and hyperammonemia was detected. We performed abdominal MR angiography, which visualized an intrahepatic portal systemic shunt. Cerebral blood flow, measured by xenon-enhanced computed tomography, was decreased in the bilateral, but more dominantly right-sided, parietal watershed regions. We speculate that these boundary territories might be susceptible to damage by toxic metabolites of hepatic encephalopathy.

Rho-kinase plays an important role in hypertension and is reported to interfere with insulin signaling through serine phosphorylation of insulin receptor substrate-1 (IRS-1) in cultured vascular smooth muscle cells. We therefore examined the role of Rho-kinase in the development of insulin resistance in Zucker obese rats. In skeletal muscles and aortic tissues of Zucker obese rats, activation of RhoA/Rho-kinase was observed. Long-term Rho-kinase inhibition by 4 wk treatment with fasudil (a Rho-kinase inhibitor) not only reduced blood pressure but corrected glucose and lipid metabolism, with improvement in serine phosphorylation of IRS-1 and insulin signaling in skeletal muscles. Direct visualization of skeletal muscle arterioles with an intravital CCD videomicroscope demonstrated that both acetylcholine- and sodium nitroprusside-induced vasodilations were blunted, which were restored by the fasudil treatment. Furthermore, both fasudil and Y-27632 prevented the serine phosphorylation of IRS-1 induced by insulin and/or tumor necrosis factor-alpha in skeletal muscle cells. Collectively, Rho-kinase is responsible for the impairment of insulin signaling and may constitute a critical mediator linking between metabolic and hemodynamic abnormalities in insulin resistance.

Sirtuin 1 (Sirt1), a NAD[superscript +]-regulated deacetylase with numerous known positive effects on cellular and whole-body metabolism, is expressed in the renal cortex and medulla. It is known to have protective effects against age-related disease, including diabetes. Here we investigated the protective role of Sirt1 in diabetic renal damage. We found that Sirt1 in proximal tubules (PTs) was downregulated before albuminuria occurred in streptozotocin-induced or obese (db/db) diabetic mice. PT-specific SIRT1 transgenic and Sirt1 knockout mice showed prevention and aggravation of the glomerular changes that occur in diabetes, respectively, and nondiabetic knockout mice exhibited albuminuria, suggesting that Sirt1 in PTs affects glomerular function. Downregulation of Sirt1 and upregulation of the tight junction protein Claudin-1 by SIRT1-mediated epigenetic regulation in podocytes contributed to albuminuria. We did not observe these phenomena in 5/6 nephrectomized mice. We also demonstrated retrograde interplay from PTs to glomeruli using nicotinamide mononucleotide (NMN) from conditioned medium, measurement of the autofluorescence of photoactivatable NMN and injection of fluorescence-labeled NMN. In human subjects with diabetes, the levels of SIRT1 and Claudin-1 were correlated with proteinuria levels. These results suggest that Sirt1 in PTs protects against albuminuria in diabetes by maintaining NMN concentrations around glomeruli, thus influencing podocyte function., Japan. Ministry of Education, Culture, Sports, Science and Technology (Grant 22790800)

The role of dimethylarginine dimethylaminohydrolase 2 (DDAH2) in glucose metabolism is unknown. Here, we generated DDAH2 transgenic (Tg) mice. These mice had lower plasma glucose levels (60 min: 298±32 vs. 418±35 mg/dl; 120 min: 205±15 vs. 284±20 mg/dl) and higher insulin levels (15 min: 2.1±0.2 vs. 1.5±0.1 ng/ml; 30 min: 1.8±0.1 vs. 1.5±0.1 ng/ml) during intraperitoneal glucose tolerance tests when fed a high-fat diet (HFD) compared with HFD-fed wild-type (WT) mice. Glucose-stimulated insulin secretion (GSIS) was increased in Tg islets by 33%. Pancreatic asymmetrical dimethylarginine, nitric oxide, and oxidative stress levels were not correlated with improvements in insulin secretion in Tg mice. Secretagogin, an insulin vesicle docking protein, was up-regulated by 2.7-fold in Tg mice and in pancreatic MIN-6 cells overexpressing DDAH2. GSIS in MIN-6 cells was dependent on DDAH2-induced secretagogin expression. Pancreatic Sirt1, DDAH2, and secretagogin were down-regulated in HFD-fed WT mice by 70, 75, and 85%, respectively. Overexpression of Sirt1 overexpression by 3.9-fold increased DDAH2 and secretagogin expression in MIN-6 cells by 3.2- and 2.5-fold, respectively. DDAH2 overexpression improved GSIS in pancreas-specific Sirt1-deficient mice. In summary, the Sirt1/DDAH2/secretagogin pathway is a novel regulator of GSIS.

Although endothelial dysfunction, defined as abnormal vasoreactivity, is a common early finding in individuals with type 2 diabetes, the endothelium has not been known to regulate metabolism. As PPARgamma, a transcriptional regulator of energy balance, is expressed in endothelial cells, we set out to investigate the role of endothelial cell PPARgamma in metabolism using mice that lack PPARgamma in the endothelium and BM (gammaEC/BM-KO). When gammaEC/BM-KO mice were fed a high-fat diet, they had decreased adiposity and increased insulin sensitivity compared with control mice, despite increased serum FFA and triglyceride (TG) levels. After fasting or olive oil gavage, gammaEC/BM-KO mice exhibited significant dyslipidemia and failed to respond to the FFA and TG lowering effects of the PPARgamma agonist rosiglitazone. BM transplantation studies, which reconstituted hematopoietic PPARgamma, established that these metabolic phenotypes were due to endothelial PPARgamma deficiency. We further found that the impairment in TG-rich lipoprotein metabolism in gammaEC/BM-KO mice was associated with fatty acid-mediated lipoprotein lipase inhibition and changes in a PPARgamma-regulated endothelial cell transcriptional program. Despite their metabolic improvements, high-fat diet-fed gammaEC/BM-KO mice had impaired vasoreactivity. Taken together, these data suggest that PPARgamma in the endothelium integrates metabolic and vascular responses and may contribute to the effects of PPARgamma agonists, thus expanding what endothelial function and dysfunction may entail.

Peroxisome proliferator-activated receptors (PPARs) as ligand-activated nuclear receptors involved in the transcriptional regulation of lipid metabolism, energy balance, inflammation, and atherosclerosis are at the intersection of key pathways involved in the pathogenesis of diabetes and cardiovascular disease. Synthetic PPAR agonists like fibrates (PPAR-alpha) and thiazolidinediones (PPAR-gamma) are in therapeutic use to treat dyslipidaemia and diabetes. Despite strong encouraging in vitro, animal model, and human surrogate marker studies with these agents, recent prospective clinical cardiovascular trials have yielded mixed results, perhaps explained by concomitant drug use, study design, or a lack of efficacy of these agents on cardiovascular disease (independent of their current metabolic indications). The use of PPAR agents has also been limited by untoward effects. An alternative strategy to PPAR therapeutics is better understanding PPAR biology, the nature of natural PPAR agonists, and how these molecules are generated. Such insight might also provide valuable information about pathways that protect against the metabolic problems for which PPAR agents are currently indicated. This approach underscores the important distinction between the effects of synthetic PPAR agonists and the unequivocal biologic role of PPARs as key transcriptional regulators of metabolic and inflammatory pathways relevant to diabetes and atherosclerosis.

Peroxisome proliferator activated receptor-gamma (PPARgamma) ligands increase nitric oxide (NO) production and reduce systemic blood pressure. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase (NOS) inhibitor degraded by the enzyme dimethylarginine dimethylaminohydrolase (DDAH), which has two isoforms, DDAH-I and -II. In order to elucidate the mechanism whereby PPARgamma ligands affect NO metabolism, their effects on the DDAH-ADMA pathway were investigated. Six-week-old male Wister-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were maintained with or without pioglitazone (PIO), a PPARgamma ligand. After 4 weeks, serum ADMA levels and urinary daily NO excretion were analyzed. Tissue DDAH expression was examined by real-time polymerase chain reaction (PCR), immunoblotting, and immunohistochemistry. The results showed that PIO decreased serum ADMA and increased urinary NO excretion in both WKY and SHR. Also in both strains, the expression level of DDAH-II in the kidney was increased at transcriptional levels, although the DDAH-I level was unaffected. PIO lowered blood pressure in SHR, but not in WKY. We also demonstrated that PIO induced DDAH-II protein expression in Marbin-Dubin Canine Kidney (MDCK) cells, a renal tubular cell line. In conclusion, a PPARgamma ligand was here found to increase NO production partly by upregulating tissue DDAH-II expression and decreasing systemic ADMA levels. This mechanism constitutes a direct action on renal tubular cells, but is less likely to be responsible for the blood pressure-lowering effects of PPARgamma ligands. Since ADMA is one of the risk factors for cardiovascular events, this study provides compelling evidence that PPARgamma ligands have the potential for reducing cardiovascular risks.