PPARγ activation mitigates glucocorticoid receptor-induced excessive lipolysis in adipocytes via homeostatic crosstalk.

Proper balance between lipolysis and lipogenesis in adipocytes determines the release of free fatty acids (FFA) and glycerol, which is crucial for whole body lipid homeostasis. Although, dysregulation of lipid homeostasis contributes to various metabolic complications such as insulin resistance, the regulatory mechanism remains elusive. This study clarified the individual and combined roles for glucocorticoid receptor (GCR) and peroxisome proliferator-activated receptor (PPAR)γ pathways in lipid metabolism of adipocytes. In mature 3T3-L1 adipocytes, GCR activation using dexamethasone upregulated adipose triglyceride lipase (ATGL) and downregulated phosphoenolpyruvate carboxykinase (PEPCK), resulting in enhanced glycerol release into the medium. In contrast, PPARγ ligand pioglitazone modestly upregulated ATGL and hormone sensitive lipase (HSL), but markedly enhanced PEPCK and glycerol kinase (GK), thereby suppressed glycerol release. Dexamethasone showed permissive like effect on PPARγ target genes including perilipin A and aP2, therefore co-administration of dexamethasone and pioglitazone demonstrated synergistic upregulation of these enzymes excepting PEPCK, of which downregulation by dexamethasone was abolished by pioglitazone to the level above control. Thus, the excessive glycerol release was prevented as the net outcome of the co-administration. Consistently, the bodipy stain demonstrated that dexamethasone reduced the amount of cytosolic lipid, which was preserved in co-treated adipocytes. Moreover, silencing of PPARγ suppressed the synergistic effects of co-treatment on the lipolytic and lipogenic genes, and therefore the GCR pathway indeed involves PPARγ. In conclusion, crosstalk between GCR and PPARγ is largely synergistic but counter-regulatory in lipogenic genes, of which enhancement prevents excessive glycerol and possibly FFA release by glucocorticoids into the circulation.

GPR120 in adipocytes has differential roles in the production of pro-inflammatory adipocytokines.

How nutritional excess leads to inflammatory responses in metabolic syndrome is not well characterized. Here, we evaluated the effects of ω-3 polyunsaturated fatty acid specific G-protein coupled receptor 120 (GPR120) activation on inflammatory pathways in adipocytes, and the influence of this process on macrophage migration. Using 3T3-L1 adipocytes, we found that agonizing GPR120 using its synthetic ligand, GSK137647, attenuated both basal and lipopolysaccharide-induced production of interleukin-6 (IL-6) and C-C motif chemokine ligand 2 (CCL2). Moreover, the intervention reduced the phosphorylation of nuclear factor kappa B inhibitor alpha (IκBα) and nuclear translocation of nuclear factor kappa-B p65 subunit (p65). Furthermore, the silencing of GPR120 itself reduced IL-6 and CCL2 mRNA expression. Inhibition of protein kinase C (PKC) augmented the down-regulatory effect of GSK137647 on IL-6 and CCL2 mRNA. Using a luciferase assay to measure promoter activity of the IL-6 gene in mouse embryonic fibroblasts, we demonstrated that exogenous transfection of GPR120 alone reduced the promoter activity, which was augmented by GSK137647. Inhibition of PKC further reduced the promoter activity. Nevertheless, RAW 264.7 macrophages grown in conditioned medium collected from GSK137647-treated adipocytes attenuated the expressions of matrix metalloproteinases-9 and -3, and tissue inhibitor of metalloproteinase-1. Conditioned medium also inhibited the lipopolysaccharide-induced migration of these macrophages. Taken together, these findings provide critical evidence that although GPR120 is associated with a PKC-mediated pro-inflammatory pathway, the direct inhibitory effects of GPR120 on the nuclear factor kappa B pathway are anti-inflammatory. Moreover, GPR120 activity can attenuate the adipocyte-mediated enhanced production of extracellular matrix-modulating factors in macrophages and can reduce their migration by a paracrine mechanism.

Increase in tumor suppressor Arf compensates gene dysregulation in in vitro aged adipocytes.

Deterioration of adipocyte function due to increased oxidative stress predisposes patients to metabolic disorders in advanced age. However, the roles of tumor suppressors in such conditions remain largely unknown. Therefore, we aimed to address their dynamics in aged adipocytes using a long-term culture model. We compared 3T3-L1 adipocytes at 17-19 days (long-term) with those at 8-10 days (short-term) after initiation of adipogenic induction for mimicking 'aged' and 'young' adipocytes, respectively. H2O2 release and dihydroethidium (DHE) staining was increased, while superoxide dismutase (SOD) activity was reduced in long-term cultured adipocytes, which is suggestive of enhanced oxidative stress in this group. Moreover, qRT-PCR revealed increased mRNAs of Nox4 (a subunit of NADPH oxidase complex), Ccl2 (a proinflammatory chemokine) and Il6 [a marker of senescence-associated secretory phenotype (SASP)] along with decreased levels of Pparγ, Adipoq and Slc2a4 (genes related to glucose metabolism). These alterations were associated with increased expression of the tumor suppressors alternate-reading-frame protein p19Arf (Arf) and p16Ink4a. However, silencing of Arf reduced mRNAs of Adipoq and Slc2a4 and enhanced release of Il6. The effect was opposite in Arf overexpressing adipocytes, which showed reduced superoxide production as assessed with DHE staining and SOD activity. Western blots showed that Arf negatively regulates the phosphorylation of Akt. Luciferase assay in Hela cells additionally suggested that Arf negatively regulates Il6 transcriptional activity through a PI3 K/Akt mediated pathway. These findings strongly suggest that the enhanced Arf expression in oxidative stress plays compensatory protective roles against aging-related dysregulation of gene expression in adipocytes.

A sodium-glucose co-transporter 2 inhibitor empagliflozin prevents abnormality of circadian rhythm of blood pressure in salt-treated obese rats.

Studies were performed to examine the effects of the selective sodium-glucose co-transporter 2 (SGLT2) inhibitor empagliflozin on urinary sodium excretion and circadian blood pressure in salt-treated obese Otsuka Long Evans Tokushima Fatty (OLETF) rats. Fifteen-week-old obese OLETF rats were treated with 1% NaCl (in drinking water), and vehicle (0.5% carboxymethylcellulose, n=10) or empagliflozin (10 mg kg(-1)per day, p.o., n=11) for 5 weeks. Blood pressure was continuously measured by telemetry system. Glucose metabolism and urinary sodium excretion were evaluated by oral glucose tolerance test and high salt challenge test, respectively. Vehicle-treated OLETF rats developed non-dipper type blood pressure elevation with glucose intolerance and insulin resistance. Compared with vehicle-treated animals, empagliflozin-treated OLETF rats showed an approximately 1000-fold increase in urinary glucose excretion and improved glucose metabolism and insulin resistance. Furthermore, empagliflozin prevented the development of blood pressure elevation with normalization of its circadian rhythm to a dipper profile, which was associated with increased urinary sodium excretion. These data suggest that empagliflozin elicits beneficial effects on both glucose homeostasis and hypertension in salt-replete obese states.

RANKL system in vascular and valve calcification with aging.

Vascular and cardiac valve calcification is associated with cardiovascular mortality in the general population. Increasing clinical and experimental evidence suggests that inflammation accelerates the progression of calcification, which has molecules in common with bone metabolism. For example, osteopontin (OPN), osteoprotegerin (OPG), receptor activator of the nuclear factor κB ligand (RANKL), and alkaline phosphatase (ALP) are proposed to play central roles in the calcification or demineralization of atherosclerotic lesions and the calcification of cardiac valves. Abnormalities in the balance of these proteins may lead to perturbations in vascular/valve calcification. "How to prevent calcification" is a common task based on conventional data; however, several pathological findings indicate that heavily calcified plaques are stable, which may not lead to coronary events. Vulnerable plaques tend to be either noncalcified or only mildly or moderately calcified. "How to treat calcification," which depends on the details of the specific patient, thus remains a difficult challenge. In addition to the detection of calcification, characterization as well as quantification of it is necessary for optimal treatment of this pathology in the future.

Eicosapentaenoic acid upregulates VEGF-A through both GPR120 and PPARγ mediated pathways in 3T3-L1 adipocytes.

Vascular endothelial growth factor-A (VEGF-A) released from adipocytes promotes angiogenesis; and thereby ameliorates the local hypoxia-induced adipose inflammation and insulin resistance. Here, we newly found that eicosapentaenoic acid (EPA) upregulated both mRNA expression and release of VEGF-A in mature 3T3-L1 adipocytes. Silencing mRNA of G-protein coupled receptor 120 (GPR120) and specific inhibition of peroxisome proliferator-activated receptor γ (PPARγ) by GW9662 respectively attenuated the EPA-induced augmentation of VEGF-A release by adipocytes. Furthermore, transfection of GPR120 gene alone and PPARγ gene alone to HEK293 cells respectively increased the promoter activity of VEGF-A as assessed by luciferase reporter assay, which was further augmented when both genes were co-transfected. Promoter deletion analysis and chromatin immunoprecipitation assay revealed that co-transfection of GPR120 enhanced EPA-induced PPARγ binding to PPAR-response element in VEGF-A promoter region. Thus, by the synchronized activation of a membrane receptor GRP120 and a nuclear receptor PPARγ, EPA enhances VEGF-A production in adipocytes.

Effect of dipeptidyl peptidase-4 inhibition on circadian blood pressure during the development of salt-dependent hypertension in rats.

A growing body of evidence has indicated that dipeptidyl peptidase-4 (DPP-4) inhibitors have antihypertensive effects. Here, we aim to examine the effect of vildagliptin, a DPP-4-specific inhibitor, on blood pressure and its circadian-dipping pattern during the development of salt-dependent hypertension in Dahl salt-sensitive (DSS) rats. DSS rats were treated with a high-salt diet (8% NaCl) plus vehicle or vildagliptin (3 or 10 mg kg(-1) twice daily by oral gavage) for 7 days. Blood pressure was measured by the telemetry system. High-salt diet for 7 days significantly increased the mean arterial pressure (MAP), systolic blood pressure (SBP) and were also associated with an extreme dipping pattern of blood pressure in DSS rats. Treatment with vildagliptin dose-dependently decreased plasma DPP-4 activity, increased plasma glucagon-like peptide 1 (GLP-1) levels and attenuated the development of salt-induced hypertension. Furthermore, vildagliptin significantly increased urine sodium excretion and normalized the dipping pattern of blood pressure. In contrast, intracerebroventricular infusion of vildagliptin (50, 500 or 2500 µg) did not alter MAP and heart rate in DSS rats. These data suggest that salt-dependent hypertension initially develops with an extreme blood pressure dipping pattern. The DPP-4 inhibitor, vildagliptin, may elicit beneficial antihypertensive effects, including the improvement of abnormal circadian blood pressure pattern, by enhancing urinary sodium excretion.

Intracoronary administration of nicorandil during primary percutaneous coronary intervention: Impact on restoration of regional myocardial perfusion in reperfused myocardium during the subacute phase of myocardial infarction.

BACKGROUND: The impact of nicorandil as adjunctive therapy for percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI) is controversial. We performed 15O-labeled water positron emission tomography (PET) to quantify regional myocardial perfusion in patients with STEMI who received nicorandil or no adjunctive therapy during PCI. METHODS: PCI was performed within 8 h after STEMI onset in 33 patients. 14 patients received intracoronary nicorandil 2 mg immediately after recanalization of the culprit lesion (Nico group). After 3-4 weeks, PET was performed in which myocardial blood flow (MBF) was measured at baseline and during adenosine triphosphate (ATP)-induced hyperemia. Myocardial vascular resistance (MVR) was calculated for all segments. Data were obtained from the reperfused (Rep) and normal segments (Cont) in each patient. RESULTS: In patients not given nicorandil (No-Nico group), the MBF was significantly lower in Rep than that in Cont at baseline and during hyperemia (Cont vs. Rep: 0.82 ± 0.14 vs. 0.68 ± 0.11, P = 0.001, ATP-Cont vs. ATP-Rep: 2.00 ± 0.72 vs. 1.52 ± 0.61, P = 0.017), which was restored in the Nico group (Cont vs. Rep: 0.79 ± 0.17 vs. 0.78 ± 0.20; ATP-Cont vs. ATP-Rep: 2.02 ± 0.84 vs. 1.84 ± 0.62). MVR was elevated in Rep at baseline and during hyperemia in the No-Nico group. MVR elevation in Rep was prevented in the Nico group. CONCLUSIONS: 15O-labeled water PET was feasible for segmental analysis of MBF during the subacute phase of STEMI. It revealed that intracoronary administration of nicorandil to STEMI patients who underwent PCI prevented MVR elevation and thus restored MBF in the reperfused segments to a level similar to that in the normal segments.

Prognostic value of circulating regulatory T cells for worsening heart failure in heart failure patients with reduced ejection fraction.

Regulatory T cells (Tregs) play a crucial role in the negative regulation of immune responses. Recent studies suggest that Tregs are involved in the pathogenesis of atherosclerosis and myocarditis. Here, we investigated the involvement of Tregs on worsening heart failure (HF) in patients with reduced ejection fraction (HF-REF). The study population consisted of 32 HF-REF patients who were hospitalized for worsening HF, and 18 control subjects. Cardiac function was evaluated by echocardiography. A single venous blood sample was collected before discharge. Circulating T cells were evaluated by flow cytometry. Tregs were defined as CD4(+)CD25(+)Foxp3(+)T cells, and the correlations between the frequency of Tregs and CRP, IL-6 and several echoparameters were analysed. Furthermore, all HF-REF patients were followed up to 12 months from discharge to examine the predictors of recurrent hospitalization.In HF-REF patients, Tregs were significantly decreased (5.9 ± 1.4 versus 8.0 ± 2.2%, P < 0.01), while CD4(+)HLADR(+)T cells were increased (10.1 ± 5.4 versus 7.3 ± 3.1%, P < 0.05), compared with controls. Tregs were negatively correlated with left ventricular end-diastolic dimension, and levels of CRP and IL-6. Eleven of 32 HF-REF patients were rehospitalized for worsening HF within 12 months. Multivariate Cox regression analysis showed that CD4/CD8 and frequency of Tregs were independent predictors for recurrent hospitalization. Furthermore, HF-REF patients expressing under 6% Treg/CD4(+)T cells showed a significantly higher incidence of recurrent hospitalization for worsening HF within 12 months.Our data suggest that Tregs might be involved in the pathogenesis of decompensated HF, and may be a novel predictor of poor prognosis in HF-REF patients.

Valsartan ameliorates the constitutive adipokine expression pattern in mature adipocytes: a role for inverse agonism of the angiotensin II type 1 receptor in obesity.

Angiotensin (Ang) II receptor blockers (ARBs) alleviate obesity-related insulin resistance, which suggests an important role for the Ang II type 1 receptor (AT1R) in the regulation of adipocytokines. Therefore, we treated mature 3T3-L1 adipocytes with 50 µmol l(-1) of valsartan, a selective AT1R blocker without direct agonism to peroxisome proliferator-activated receptor (PPAR)-γ. In the absence of effective concentrations of Ang II, unstimulated mature adipocytes expressed and secreted high levels of interleukin (IL)-6. This constitutive proinflammatory activity was attenuated by the suppression of extracellular signal-regulated kinase phosphorylation by valsartan but was unaffected by the Ang II type 2 receptor blocker PD123319. COS7 cells co-transfected with AT1R and IL-6, which expressed NF-κB but lacked PPAR-γ, showed no constitutive but substantial ligand-dependent IL-6 reporter activity, which was counteracted by valsartan. Valsartan preserved cytosolic IκB-α and subsequently reduced nuclear NF-κB1 protein expression in mature adipocytes. Interestingly, valsartan did not increase PPAR-γ messenger RNA expression per se but enhanced the transcriptional activity of PPAR-γ in mature adipocytes; this enhancement was accompanied by upregulation of the PPAR coactivator (PGC)-1α. Moreover, T0090907, a PPAR-γ inhibitor, increased IL-6 expression, and this increase was attenuated by valsartan. Indeed, addition of valsartan without direct PPAR-γ agonism increased adiponectin production in mature adipocytes. Together, the findings indicate that valsartan blocks the constitutive AT1R activity involving the NF-κB pathway that limits PPAR-γ activity in mature adipocytes. Thus, inverse agonism of AT1R attenuates the spontaneous proinflammatory response and enhances the constitutive insulin-sensitizing activities of mature adipocytes, which may underlie the beneficial metabolic impacts of ARBs.

The cyclin-dependent kinase inhibitor p21 is essential for the beneficial effects of renal ischemic preconditioning on renal ischemia/reperfusion injury in mice.

The cyclin-dependent kinase inhibitor p21 plays important roles in chronic renal disorders; however, its roles in response to acute renal stress are unclear. Here we evaluated p21 in acute kidney injury and ischemic preconditioning using wild-type and p21 knockout mice that underwent renal ischemia followed by reperfusion. The decline in renal function and histological changes were worse in the knockout than in wild-type mice. Ischemia/reperfusion increased p21 expression in the kidney of wild-type mice compared with sham surgery, suggesting p21 may confer tolerance to ischemia/reperfusion injury. We next tested whether p21 is associated with the protective effect of ischemic preconditioning, an established method to reduce ischemia/reperfusion injury. Ischemic preconditioning attenuated ischemia/reperfusion injury in wild-type but not p21-knockout mice. This preconditioning decreased the number of proliferating tubular cells before but increased them at 24 h after ischemia/reperfusion in the kidneys of wild-type mice. In p21-knockout mice, ischemic preconditioning did not change the number of proliferating cells before but decreased them after ischemia/reperfusion. Ischemic preconditioning increased renal p21 expression and the number of cells in the G1 phase of the cell cycle before ischemia/reperfusion compared with sham surgery. Thus, renal p21 is essential for the beneficial effects of renal ischemic preconditioning. Transient cell cycle arrest induced by ischemic preconditioning by a p21-dependent pathway seems to be important for subsequent tubular cell proliferation after ischemia/reperfusion.

Calcium channel blocker enhances beneficial effects of an angiotensin II AT1 receptor blocker against cerebrovascular-renal injury in type 2 diabetic mice.

Recent clinical trials have demonstrated that combination therapy with renin-angiotensin system inhibitors plus calcium channel blockers (CCBs) elicits beneficial effects on cardiovascular and renal events in hypertensive patients with high cardiovascular risks. In the present study, we hypothesized that CCB enhances the protective effects of an angiotensin II type 1 receptor blocker (ARB) against diabetic cerebrovascular-renal injury. Saline-drinking type 2 diabetic KK-A(y) mice developed hypertension and exhibited impaired cognitive function, blood-brain barrier (BBB) disruption, albuminuria, glomerular sclerosis and podocyte injury. These brain and renal injuries were associated with increased gene expression of NADPH oxidase components, NADPH oxidase activity and oxidative stress in brain and kidney tissues as well as systemic oxidative stress. Treatment with the ARB, olmesartan (10 mg/kg/day) reduced blood pressure in saline-drinking KK-A(y) mice and attenuated cognitive decline, BBB disruption, glomerular injury and albuminuria, which were associated with a reduction of NADPH oxidase activity and oxidative stress in brain and kidney tissues as well as systemic oxidative stress. Furthermore, a suppressive dose of azelnidipine (3 mg/kg/day) exaggerated these beneficial effects of olmesartan. These data support the hypothesis that a CCB enhances ARB-associated cerebrovascular-renal protective effects through suppression of NADPH oxidase-dependent oxidative stress in type 2 diabetes.

Mifepristone promotes adiponectin production and improves insulin sensitivity in a mouse model of diet-induced-obesity.

The steroid receptor antagonist mifepristone is used as an anti-cancer agent, eliciting both cytostatic and cytotoxic effects on malignant cells. However, the metabolic effects of long-term treatment with mifepristone have remained unclear. The effects of mifepristone on insulin sensitivity and adiponectin secretion were evaluated both in in vivo and in vitro. First, we explored the effects of mifepristone, on metabolic functions in obese mice receiving a high-fat diet. When these mice were fed mifepristone, they exhibited a marked improvement in insulin sensitivity, attenuated hepatic injury, and decreased adipocyte size, compared with mice that received only the high-fat diet. Intriguingly, mifepristone-treated mice showed significantly elevated plasma adiponectin levels. Second, we tested the effects of mifepristone on differentiated 3T3-L1 adipocytes in vitro. When differentiated adipocytes were treated with mifepristone for 48 h, adiponectin was upregulated at both mRNA and protein levels. Collectively, these results reveal novel actions of mifepristone on metabolic functions, in vivo and in vitro, in which the drug exerts antidiabetic effects associated with an upregulation in adiponectin-secretion.

Angiotensin-converting enzyme inhibitor does not suppress renal angiotensin II levels in angiotensin I-infused rats.

Angiotensin II (Ang II) infusion into rats elevates local angiotensin II levels through an AT1 receptor-dependent pathway in the kidney. We examined whether treatment with an angiotensin-converting enzyme (ACE) inhibitor, temocapril, or an AT1-receptor blocker, olmesartan, prevented elevation of Ang II levels in the kidney of angiotensin I (Ang I)-infused rats. Rats were infused with Ang I (100 ng/min) and treated with temocapril (30 mg/kg per day, n = 10) or olmesartan (10 mg/kg per day, n = 9) for 4 weeks. Ang I infusion significantly elevated blood pressure compared with vehicle-infused rats (n = 6). Treatment with temocapril or olmesartan suppressed Ang I-induced hypertension. Temocapril suppressed both plasma and renal ACE activity. Ang I infusion increased Ang II content in the kidney. Interestingly, temocapril failed to reduce the level of Ang II in the kidney, while olmesartan markedly suppressed an increase in renal Ang II levels. These results suggest a limitation of temocapril and a benefit of olmesartan to inhibit the renal renin-angiotensin system and suggest the possible existence of an ACE inhibitor-insensitive pathway that increases Ang II levels in rat kidney.

Pioglitazone promotes preadipocyte proliferation by downregulating p16(Ink4a).

Pioglitazone, a synthetic ligand of peroxisome proliferator-activated receptor (PPAR)γ, causes preadipocyte proliferation through a mechanism which still remains elusive. Here, to address the mechanism, we investigated the effects of PPARγ and pioglitazone on the kinetics of cyclin-dependent kinase inhibitors, especially with p16(Ink4a) (p16) centered, by employing 3T3-L1 preadipocytes. Pioglitazone promoted preadipocyte proliferation by increasing S and G(2)/M cell-cycle entry, which was accompanied by decreased p16 mRNA expression. PPARγ overexpression along with the luciferase reporter assay confirmed that PPARγ was crucial for the downregulation of p16 mRNA transcription, and that the action was augmented by pioglitazone. Thus, pioglitazone exerted cell-cycle dependent promoting effect on preadipocyte proliferation, of which mechanisms include p16-downregulation through PPARγ.

Lipid peroxidation-induced VEGF expression in the skin of KKAy obese mice.

Obesity is known to be associated with a number of effects on skin physiology. KKA(y) obese mouse is a model of type 2 diabetes characterized by systemic oxidative stress because of severe obesity, hypertriglyceridaemia, hyperglycaemia and hyperinsulinaemia. We investigated lipid peroxidation and vascular endothelial growth factor (VEGF) expression in the skin of KKA(y) obese mice. We also investigated the effect of lipid peroxidation derivatives on VEGF production and proliferation in human epidermal keratinocyte cell line (HaCaT). The lipid peroxidation level in the mouse skin tissue was determined by measuring the levels of thiobarbituric acid-reactive substances. The levels of VEGF expression, p44/p42 mitogen-activated protein kinase (MAPK) activation and CD36 expression were analysed by Western blot. Their localization was examined by immunofluorescence. For the in vitro experiments, an enzyme-linked immunosorbent assay was utilized to measure VEGF secretion in the medium. In vitro experiments demonstrated that lipid peroxidation derivatives increased VEGF production in HaCaT cells, which was blocked by a p44/p42 MAPK inhibitor and anti-CD36 antibody. We observed increased levels of lipid peroxidation derivatives, p44/p42 MAPK activation and VEGF expression in the skin of KKA(y) obese mice. Notably, pitavastatin, an inhibitor of competitive 3-hydroxy-3-methylglutaryl coenzyme A reductase, suppressed all of these processes. Our results suggest that lipid peroxidation induces VEGF expression via CD36 and p44/p42 MAPK pathway in the skin of obese mice.

Beneficial direct adipotropic actions of pitavastatin in vitro and their manifestations in obese mice.

OBJECTIVE: Prevention of cardiovascular complications in obese patients frequently includes statin administration for coexisting dyslipidemia. Herein, we investigated the impacts of pitavastatin at clinically relevant doses on adipose dysfunction and insulin resistance. METHODS: We treated 3T3-L1 preadipocytes with 10-100 ng/ml pitavastatin from initiation of differentiation (Day 0) to Day 8 (differentiation/maturation phase) or from Day 8 to Day 16 (post-maturation phase). Subsequently, we administered pitavastatin (6.2mg/day/kg) to 7-week-old female KKAy mice for 6 weeks; untreated KKAy mice served as obese controls. RESULTS: Pitavastatin impaired neither lipogenesis nor adiponectin expression during the differentiation/maturation phase. During the post-maturation phase, pitavastatin prevented excessive triglyceride accumulation, which was associated with attenuated glucose transporter-4 expression, and dose-dependently upregulated hormone-sensitive lipase expression. Decrements in the adiponectin/plasminogen activator-1 ratio were also dose-dependently inhibited. In KKAy mice, Coulter counter analyses revealed that pitavastatin treatment significantly decreased (by 16.8%) the frequency of hypertrophic adipocytes (>150 microm in diameter) in parametrial adipose pads, of which total weight remained unaltered. Correspondingly, plasma adiponectin was significantly higher in pitavastatin-treated KKAy mice than in the untreated KKAy mice (12.5+/-3.8 microg/ml vs. 8.3+/-1.5 microg/ml, p<0.05). Moreover, the area under the time-glucose curve after intraperitoneal insulin was decreased by 16% in pitavastatin-treated KKAy mice (p<0.05 vs. untreated controls). CONCLUSIONS: Pitavastatin did not impair differentiation/maturation of preadipocytes and prevented their deterioration with hypertrophy after maturation at clinical concentrations in vitro. These effects likely contributed to improved insulin sensitivity, in an obese model, via prevention of adipocyte hypertrophy and adipocytokine dysregulation.

Acute improvement of cardiac efficiency measured by 11C-acetate PET after cardiac resynchronization therapy and clinical outcome.

The purpose of this study was to examine the usefulness of (11)C-acetate positron emission tomography (PET) for assessing the efficacy of cardiac resynchronization therapy (CRT). Enrolled in this study were 20 patients with severe heart failure. All patients underwent 11C-acetate PET within 1 week after CRT. The oxygen consumption was measured by the monoexponential clearance rate of 11C-acetate (K(mono)) for both CRT-off and -on. Cardiac efficiency (CE) was determined using the concept of the work metabolic index (WMI). WMI was calculated as WMI = (stroke volume index) x (systolic blood pressure) x (heart rate)/K(mono). The patients were divided into two groups: 14 patients with improved CE (from 5.27 +/- 0.91 to 6.77 +/- 1.12) and 6 patients with deteriorated CE (from 5.35 +/- 0.92 to 4.86 +/- 0.84) by CRT-on. K(mono) decreased from 0.053 +/- 0.006 to 0.046 +/- 0.003 by CRT-on in the improved CE group (p = 0.028), but increased from 0.049 +/- 0.006 to 0.050 +/- 0.006 in the deteriorated-CE group (p = 0.036). Stroke volume index, systolic blood pressure, and heart rate did not change by CRT-on for either group. At the one-year follow-up, there were significantly higher rates of major cardiac adverse events in the deteriorated-CE group than in the improved-CE group (p = 0.032). Therefore, the improvement of CE, as assessed by 11C-acetate PET in the early period after CRT, is produced by the decrease in oxygen consumption in patients showing good responses to CRT. The decrease in oxygen consumption in the early period after CRT is thus a useful marker for predicting a good clinical outcome after CRT.

Organohalogen compounds in deep-sea fishes from the western North Pacific, off-Tohoku, Japan: Contamination status and bioaccumulation profiles.

Twelve species of deep-sea fishes collected in 2005 from the western North Pacific, off-Tohoku, Japan were analyzed for organohalogen compounds. Among the compounds analyzed, concentrations of DDTs and PCBs (up to 23,000 and 12,400 ng/g lipid wt, respectively) were the highest. The present study is the foremost to report the occurrence of brominated flame retardants such as PBDEs and HBCDs in deep-sea organisms from the North Pacific region. Significant positive correlations found between delta(15)N ( per thousand) and PCBs, DDTs and PBDEs suggest the high biomagnification potential of these contaminants in food web. The large variation in delta(13)C (per thousand) values observed between the species indicate multiple sources of carbon in the food web and specific accumulation of hydrophobic organohalogen compounds in benthic dwelling carnivore species like snubnosed eel. The results obtained in this study highlight the usefulness of deep-sea fishes as sentinel species to monitor the deep-sea environment.