IRAP deficiency attenuates diet-induced obesity in mice through increased energy expenditure.

UNLABELLED: Activation of the adipose renin-angiotensin system contributes to the development of obesity and metabolic syndrome. Insulin-regulated aminopeptidase (IRAP) has been identified a key regulator of GLUT4 transporter as well as angiotensin IV (AngIV) receptor (AT4R). Although AngII-AT1R axis appears as anorexigenic and as an effector of energy expenditure, the impact of AngIV-IRAP/AT4R axis on energy metabolism remains unknown. The aim was to determine the role of IRAP in energy metabolism in mice. METHODS AND RESULTS: In adipocyte culture, plasminogen activator inhibitor type 1 (PAI-1) expression levels were diminished in IRAP knockout (IRAP(-/-)) if compared with those of wild-type (C57Bl/6J, WT) mice. Mice were fed high-fat diet (32% fat) at age of 8 weeks. At the entry, body weight, body fat content, and parameters of saccharometabolism were similar between groups. However, IRAP(-/-) mice exhibited blunted body weight gain compared to that of WT mice, despite comparable food intake and physical activity. At 20weeks of age, IRAP(-/-) mice had 25% lower body weight than WT mice. Glucose and insulin tolerance tests revealed that the glucose disposal and the hypoglycemic effect of insulin were pronounced in IRAP(-/-) mice after a high fat diet. Indirect calorimetry demonstrated that whole-body oxygen consumption rates were significantly higher in IRAP(-/-) mice by 18% with mild hyperthermia. Analysis of brown adipose tissue (BAT) in IRAP(-/-) showed increased levels of uncoupling protein-1 (UCP-1) at basal level and adaptive thermogenesis was not impaired. CONCLUSIONS: IRAP deficiency may lead to suppression of PAI-1 expression in adipocytes and upregulation of UCP-1-mediated thermogenesis in BAT and increased energy expenditure to prevent the development of obesity, and these facts suggest a therapeutic potential of IRAP/AT4R blockade in diet-induced obesity.

Omentin prevents myocardial ischemic injury through AMP-activated protein kinase- and Akt-dependent mechanisms.

OBJECTIVES: This study examined the impact of omentin on myocardial injury in a mouse model of ischemia/reperfusion (I/R) and explored its underlying mechanisms. BACKGROUND: Obesity is a major risk factor for ischemic heart disease. Omentin is a circulating adipokine that is down-regulated by obesity. METHODS: In patients who underwent successful reperfusion treatment after acute myocardial infarction, cardiac function and perfusion defect were assessed by using scintigraphic images. Mice were subjected to myocardial ischemia followed by reperfusion. RESULTS: This study found that high levels of plasma omentin were associated with improvement of heart damage and function after reperfusion therapy in patients with acute myocardial infarction. Systemic administration of human omentin to mice led to a reduction in myocardial infarct size and apoptosis after I/R, which was accompanied by enhanced phosphorylation of AMP-activated protein kinase (AMPK) and Akt in the ischemic heart. Fat-specific overexpression of human omentin also resulted in reduction of infarct size after I/R. Blockade of AMPK or Akt activity reversed omentin-induced inhibition of myocardial ischemic damage and apoptosis in mice. In cultured cardiomyocytes, omentin suppressed hypoxia/reoxygenation-induced apoptosis, which was blocked by inactivation of AMPK or Akt. CONCLUSIONS: Our data indicate that omentin functions as an adipokine that ameliorates acute ischemic injury in the heart by suppressing myocyte apoptosis through both AMPK- and Akt-dependent mechanisms.

iPS cell sheets created by a novel magnetite tissue engineering method for reparative angiogenesis.

Angiogenic cell therapy represents a novel strategy for ischemic diseases, but some patients show poor responses. We investigated the therapeutic potential of an induced pluripotent stem (iPS) cell sheet created by a novel magnetite tissue engineering technology (Mag-TE) for reparative angiogenesis. Mouse iPS cell-derived Flk-1(+) cells were incubated with magnetic nanoparticle-containing liposomes (MCLs). MCL-labeled Flk-1(+) cells were mixed with diluted extracellular matrix (ECM) precursor and a magnet was placed on the reverse side. Magnetized Flk-1(+) cells formed multi-layered cell sheets according to magnetic force. Implantation of the Flk-1(+) cell sheet accelerated revascularization of ischemic hindlimbs relative to the contralateral limbs in nude mice as measured by laser Doppler blood flow and capillary density analyses. The Flk-1(+) cell sheet also increased the expressions of VEGF and bFGF in ischemic tissue. iPS cell-derived Flk-1(+) cell sheets created by this novel Mag-TE method represent a promising new modality for therapeutic angiogenesis.

Small low-density lipoprotein cholesterol concentration is a determinant of endothelial dysfunction by peripheral artery tonometry in men.

AIM: Endothelial dysfunction is an initial step in the progression of atherosclerosis. Precise measurements of lipoprotein subclass distribution by high-performance liquid chromatography (HPLC) have been established. Here, we investigated the potential associations between lipoprotein subclass cholesterol concentrations and endothelial dysfunction evaluated by digital reactive hyperemia peripheral arterial tonometry (PAT). METHODS: We recruited 120 apparently healthy Japanese men. Endothelial function was assessed by digital reactive hyperemia PAT, expressed as the logarithmic-scaled reactive hyperemia index (RHI). Plasma cholesterol concentrations in lipoproteins and their subclasses were determined by HPLC with gel permeation columns. RESULTS: RHI was inversely correlated with age (r=-0.258, p=0.004), followed by LDL cholesterol (r=-0.236, p=0.010) and small LDL cholesterol (r=-0.223, p=0.014). In addition, RHI was significantly inversely associated with heart rate, hemoglobin A1c, total cholesterol, medium LDL cholesterol, apolipoprotein B100, and non-HDL cholesterol. In stepwise multiple regression analysis, age (ß=-0.266, p=0.024), small LDL cholesterol (ß=-0.213, p=0.015), and heart rate (ß=-0.183, p=0.036) were found to be independent determinants of RHI (adjusted R(2) =0.132, p<0.001). CONCLUSIONS: Small LDL cholesterol concentration was an important, independent determinant of endothelial dysfunction in men.

Cholesterol and triglyceride concentrations in lipoproteins as related to carotid intima-media thickness.

Since distinct cholesterol and triglyceride concentrations in major lipoproteins and their subclasses may be related to atherosclerosis, we investigated the relationship of cholesterol and triglyceride concentrations in lipoprotein subclasses and the severity of carotid intima-media thickness (IMT), a surrogate marker of subclinical atherosclerosis. We studied 116 apparently healthy Japanese men (53 ± 9 years) without a history of cardiovascular diseases who were not taking any medication. Carotid IMT was measured by means of high-resolution vascular ultrasound. Plasma cholesterol and triglyceride concentrations in major lipoproteins and their subclasses were determined by HPLC with gel permeation columns. By univariate analyses, carotid IMT was the most closely related to age (r = 0.528, P < 0.001), followed by smoking habit expressed as pack-year cigarette consumption (r = 0.409, P < 0.001). In addition to total cholesterol and LDL cholesterol, carotid IMT was significantly associated with cholesterol and triglyceride concentrations in several LDL and VLDL subclasses. Stepwise multiple linear regression analysis revealed that age (ß = 0.436, P < 0.001), smoking (pack-years) (ß = 0.225, P = 0.007), and large LDL cholesterol (ß = 0.175, P = 0.023) were independent predictors of determining carotid IMT (adjusted R(2) = 0.347, P < 0.001). These results indicate that large LDL cholesterol is an important, independent determinant of carotid IMT in healthy men.

Enhanced angiogenesis by transplantation of mesenchymal stem cell sheet created by a novel magnetic tissue engineering method.

OBJECTIVE: Therapeutic angiogenesis with cell transplantation represents a novel strategy for severe ischemic diseases. However, some patients have poor response to such conventional injection-based angiogenic cell therapy. Here, we investigated a therapeutic potential of mesenchymal stem cell (MSC) sheet created by a novel magnetite tissue engineering technology for reparative angiogenesis. METHODS AND RESULTS: Human MSCs incubated with magnetic nanoparticle-containing liposomes were cultured, and a magnet was placed on the reverse side. Magnetized MSCs formed multilayered cell sheets according to magnetic force. Nude mice were subjected to unilateral hind limb ischemia and separated into 3 groups. For the control group, saline was injected into ischemic tissue. In the MSC-injected group, mice received magnetized MSCs by conventional needle injections without sheet formula as a control cell group. In the MSC-sheet group, MSC sheet was layered onto the ischemic tissues before skin closure. Blood flow recovery and the extent of angiogenesis were assessed by a laser Doppler blood flowmetry and histological capillary density, respectively. The MSC-sheet group had a greater angiogenesis in ischemic tissues compared to the control and MSC-injected groups. The angiogenic and tissue-preserving effects of MSC sheets were attributable to an increased expression of vascular endothelial growth factor and reduced apoptosis in ischemic tissues. In cultured MSCs, magnetic labeling itself inhibited apoptosis via a catalase-like antioxidative mechanism. CONCLUSIONS: MSC sheet created by the novel magnetic nanoparticle-based tissue engineering technology would represent a new modality for therapeutic angiogenesis and tissue regeneration.

High serum concentrations of pentosidine, an advanced glycation end product, are associated with low normal value of ankle-brachial index in apparently healthy men.

The ankle-brachial index (ABI) is widely used for peripheral arterial disease screening and is associated with future cardiovascular events. Pentosidine, an advanced glycation end product, accumulates with age and in diabetes and end-stage renal disease; but the significance of elevated serum pentosidine is not well known. We investigated the relationship of the ABI to circulating pentosidine concentrations as well as other atherogenic factors in apparently healthy men. The study group consisted of a total of 170 apparently healthy men (age, 55 ± 9 years). Serum pentosidine concentrations were measured by enzyme-linked immunosorbent assay. The mean ABI and pentosidine concentrations of the whole study group were 1.16 ± 0.07 (range, 0.98-1.35) and 36.1 ± 10.6 ng/mL (range, 11.2-81.0), respectively. Univariate analysis showed that the ABI was inversely correlated with pentosidine (P = .0004), small low-density lipoprotein (LDL) cholesterol (P = .017), LDL cholesterol (P = .019), apolipoprotein B (P = .024), fasting insulin (P = .028), very small LDL cholesterol (P = .036), difference in ABIs between legs (P = .037), malondialdehyde-modified LDL (P = .044), and homeostasis model assessment of insulin resistance (P = .047). Stepwise multiple linear regression analysis revealed that increased pentosidine, fasting insulin, small LDL cholesterol, difference in ABIs between legs, difference in systolic blood pressure between arms, and reduced body mass index were independent determinants of reduced ABI (adjusted R(2) = 0.237, P < .0001). Serum pentosidine was an important, independent determinant of ABI in healthy men. Subjects with an ABI less than 1.10 showed higher pentosidine concentrations.

Ischemia-induced angiogenesis is impaired in aminopeptidase A deficient mice via down-regulation of HIF-1α.

Aminopeptidase A (APA; EC 3.4.11.7) is a transmembrane metalloprotease with several functions in tumor angiogenesis. To investigate the role of APA in the process of ischemia-induced angiogenesis, we evaluated the cellular angiogenic responses under hypoxic conditions and the process of perfusion recovery in the hindlimb ischemia model of APA-deficient (APA-KO; C57Bl6/J strain) mice. Western blotting of endothelial cells (ECs) isolated from the aorta of APA-KO mice revealed that the accumulation of hypoxia-inducible factor-1α (HIF-1α) protein in response to hypoxic challenge was blunted. Regarding the proteasomal ubiquitination, a proteasome inhibitor MG-132 restored the reduced accumulation of HIF-1α in ECs from APA-KO mice similar to control mice under hypoxic conditions. These were associated with decreased growth factor secretion and capillary formation in APA-KO mice. In the hindlimb ischemia model, perfusion recovery in APA-KO mice was decreased in accordance with a significantly lower capillary density at 2weeks. Regarding vasculogenesis, no differences were observed in cell populations and distribution patterns between wild type and APA-KO mice in relation to endothelial progenitor cells. Our results suggested that Ischemia-induced angiogenesis is impaired in APA-KO mice partly through decreased HIF-1α stability by proteasomal degradation and subsequent suppression of HIF-1α-driven target protein expression such as growth factors. APA is a functional target for ischemia-induced angiogenesis.

Very small low-density lipoprotein cholesterol level is a determinant of arterial stiffness in men with impaired glucose metabolism.

AIM: Pulse wave velocity (PWV), an estimate of arterial stiffness, is an important predictor of cardiovascular risk. The aim of this study was to investigate the relationship between lipoprotein subclasses and brachial-ankle PWV (baPWV). METHODS: A total of 131 apparently healthy Japanese men without a history of cardiovascular disease were divided into two groups: normal glucose metabolism (n =87) and impaired glucose metabolism (n =44). Cholesterol concentrations of major lipoproteins and their subclasses were determined by HPLC with gel permeation columns. RESULTS: In the normal glucose metabolism group, age, systolic blood pressure, and diastolic pressure were associated with increased baPWV, and a stepwise multiple linear regression analysis revealed that age (p =0.022) and systolic blood pressure (p < 0.001) were significantly independent determinants of baPWV. In the impaired glucose metabolism group, age (p =0.002), very small LDL cholesterol (p =0.012), systolic blood pressure (p =0.021), and the fasting plasma glucose concentration (p =0.038) were identified as independent determinants of baPWV, although a univariate analysis revealed significant relationships of several plasma lipid compositions or species to baPWV. CONCLUSIONS: In addition to aging, hypertension and glucose levels, very small LDL cholesterol levels appear to play an important role in the development of arterial stiffness in men with impaired glucose metabolism.

Unmetabolized fenofibrate, but not fenofibric acid, activates AMPK and inhibits the expression of phosphoenolpyruvate carboxykinase in hepatocytes.

AIMS: A lipid-lowering agent, fenofibrate, has been reported to reduce hepatic glucose production and the expression of phosphoenolpyruvate carboxykinase (PEPCK), a rate-limiting enzyme for gluconeogenesis in the liver. However, the precise mechanisms of these effects have remained unclear. MAIN METHODS: Rat hepatoma-derived H4IIE cells and murine myoblast-derived C2C12 cells were incubated with the ester form of fenofibrate and fenofibric acid, a metabolite of fenofibrate ester, and the phosphorylation of AMPK, acetyl-CoA carboxylase (ACC), PEPCK mRNA expression and glucose production were assessed. KEY FINDINGS: Incubation of H4IIE hepatoma cells with the ester form of fenofibrate increased the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) and decreased PEPCK mRNA expression and glucose production. Fenofibrate-induced reductions in PEPCK expression and glucose production were abrogated by compound C, a specific AMPK inhibitor. Fenofibric acid, a metabolite of fenofibrate ester, had no effects on AMPK phosphorylation, PEPCK gene expression, or glucose production in H4IIE cells. Fenofibrate-treated mice exhibited increases in AMPK phosphorylation and a decrease in PEPCK expression in the liver but not in skeletal muscles, suggesting that unmetabolized fenofibrate accumulated and affected AMPK only in the liver. SIGNIFICANCE: These results demonstrate that fenofibrate inhibits PEPCK gene expression and hepatic glucose production in the liver via AMPK activation, even though the metabolite loses its effects on AMPK and does not work in vivo in myocytes. This novel feature of fenofibrate may provide additional benefit for the treatment of patients with disorders of both lipid and glucose metabolism.

Therapeutic angiogenesis by transplantation of induced pluripotent stem cell-derived Flk-1 positive cells.

BACKGROUND: Induced pluripotent stem (iPS) cells are the novel stem cell population induced from somatic cells. It is anticipated that iPS will be used in the expanding field of regenerative medicine. Here, we investigated whether implantation of fetal liver kinase-1 positive (Flk-1+) cells derived from iPS cells could improve angiogenesis in a mouse hind limb model of ischemia. RESULTS: Flk-1+ cells were induced from iPS cells after four to five days of culture. Hind limb ischemia was surgically induced and sorted Flk-1+ cells were directly injected into ischemic hind limbs of athymic nude mice. Revascularization of the ischemic hind limb was accelerated in mice that were transplanted with Flk-1+ cells compared with control mice, which were transplanted with vehicle, as evaluated by laser Doppler blood flowmetry. Transplantation of Flk-1+ cells also increased expression of VEGF mRNA in ischemic tissue compared to controls. CONCLUSIONS: Direct local implantation of iPS cell-derived Flk-1+ cells would salvage tissues from ischemia. These data indicate that iPS cells could be valuable in the therapeutic induction of angiogenesis.

Angiotensin II type 1 receptor blockers prevent tumor necrosis factor-alpha-mediated endothelial nitric oxide synthase reduction and superoxide production in human umbilical vein endothelial cells.

Decrease in endothelial nitric oxide synthase (eNOS) expression is one of the adverse outcomes of endothelial dysfunction. Tumor necrosis factor-alpha (TNF-alpha) is known to decrease eNOS expression and is an important mediator of endothelial dysfunction. We hypothesized that an angiotensin II type 1 (AT1) receptor blocker would improve endothelial function via not only inhibition of the angiotensin II signaling but also inhibition of the TNF-alpha-mediated signaling. Therefore we investigated whether an AT1 receptor blocker would restore the TNF-alpha-induced decrease in eNOS expression in cultured human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with an antioxidant (superoxide dismutase, alpha-tocopherol) or AT1 receptor blockers (olmesartan or candesartan) restored the TNF-alpha-dependent reduction of eNOS. The AT1 receptor blocker decreased the TNF-alpha-dependent increase of 8-isoprostane. The superoxide dismutase activities in HUVEC were stable during AT1 receptor blocker treatment, and the AT1 receptor blocker did not scavenge superoxide directly. The AT1 receptor blocker also decreased TNF-alpha-induced phosphorylation of I kappaB alpha and cell death. These results suggest that AT1 receptor blockers are able to ameliorate TNF-alpha-dependent eNOS reduction or cell injury by inhibiting superoxide production or nuclear factor-kappaB activation.

Low folate levels may be an atherogenic factor regardless of homocysteine levels in young healthy nonsmokers.

Low folate and high homocysteine levels are emerging as important risk factors for atherosclerosis and predictors of early coronary heart disease. We evaluated folate and homocysteine levels, compared them with endothelial function, and analyzed their association with the methylenetetrahydrofolate reductase (MTHFR) and endothelial nitric oxide synthase genotypes. We recruited 71 young healthy male nonsmokers without overt cardiovascular or renal disease. Plasma homocysteine levels were enhanced 2-fold in the subjects with the MTHFR 677T/T compared with the others (P = .0001) and also enhanced in the subjects with the endothelial nitric oxide synthase -786C allele (P = .031). Homocysteine levels were independently predicted only by the MTHFR genotype. A relationship between folate and homocysteine levels was not significant. Plasma folate levels were associated independently either with high-density lipoprotein cholesterol levels or with endothelial function in the brachial artery. These results suggest that low folate levels may be a risk factor for cardiovascular diseases regardless of homocysteine levels and that the subjects with lower folate levels should be recommended for dietary folic acid supplementation to elevate endothelial function and probably increase high-density lipoprotein cholesterol levels.

Actin cytoskeleton regulates stretch-activated Ca2+ influx in human pulmonary microvascular endothelial cells.

During high tidal volume mechanical ventilation in patients with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), regions of the lung are exposed to excessive stretch, causing inflammatory responses and further lung damage. In this study, the effects of mechanical stretch on intracellular Ca(2+) concentration ([Ca(2+)](i)), which regulates a variety of endothelial properties, were investigated in human pulmonary microvascular endothelial cells (HPMVECs). HPMVECs grown on fibronectin-coated silicon chambers were exposed to uniaxial stretching, using a cell-stretching apparatus. After stretching and subsequent unloading, [Ca(2+)](i), as measured by fura-2 fluorescence, was transiently increased in a strain amplitude-dependent manner. The elevation of [Ca(2+)](i) induced by stretch was not evident in the Ca(2+)-free solution and was blocked by Gd(3+), a stretch-activated channel inhibitor, or ruthenium red, a transient receptor potential vanilloid inhibitor. The disruption of actin polymerization with cytochalasin D inhibited the stretch-induced elevation of [Ca(2+)](i). In contrast, increases in [Ca(2+)](i) induced by thapsigargin or thrombin were not affected by cytochalasin D. Increased actin polymerization with sphingosine-1-phosphate or jasplakinolide enhanced the stretch-induced elevation of [Ca(2+)](i). A simple network model of the cytoskeleton was also developed in support of the notion that actin stress fibers are required for efficient force transmission to open stretch-activated Ca(2+) channels. In conclusion, mechanical stretch activates Ca(2+) influx via stretch-activated channels which are tightly regulated by the actin cytoskeleton different from other Ca(2+) influx pathways such as receptor-operated and store-operated Ca(2+) entries in HPMVECs. These results suggest that abnormal Ca(2+) homeostasis because of excessive mechanical stretch during mechanical ventilation may play a role in the progression of ALI/ARDS.

The number and function of circulating CD34(+)CD133(+) progenitor cells decreased in stable coronary artery disease but not in acute myocardial infarction.

OBJECTIVE: Circulating CD34(+)CD133(+) cells are one of the main sources of circulating endothelial progenitor cells (EPCs). Age is inversely related to the number and function of CD34(+)CD133(+) progenitor cells in stable coronary artery disease (CAD), but the relationship remains unclear in acute myocardial infarction (AMI). The authors aimed to clarify how ageing affects the number and function of mobilised CD34(+)CD133(+) progenitor cells in AMI. DESIGN AND RESULTS: Circulating CD34(+)CD133(+) progenitor cells were measured by flow cytometry. Measurements were made at admission for CAD, or on day 7 after the onset of AMI. In stable CAD (n=131), circulating CD34(+)CD133(+) cells decreased with age (r=-0.344, p<0.0001). In AMI, circulating CD34(+)CD133(+) cells did not correlate with age (n=50), and multivariate analysis revealed that the decreased number of circulating CD34(+)CD133(+) cells was associated with male sex and higher peak creatinine kinase. The ability to give rise to functional EPCs, which show good migratory and tube-forming capabilities, deteriorated among stable CAD subjects (n=10) compared with AMI subjects (N=6). CONCLUSIONS: In stable CAD, the number and function of circulating CD34(+)CD133(+) progenitor cells decreased with age, whereas those mobilised and circulating in AMI did not.

Ablation of angiotensin IV receptor attenuates hypofibrinolysis via PAI-1 downregulation and reduces occlusive arterial thrombosis.

OBJECTIVE: Reduced fibrinolytic activity is associated with adverse cardiovascular events. Although insulin-regulated aminopeptidase (IRAP) was recently identified as the angiotensin (Ang) IV receptor (AT4R), the impact of AngIV-AT4R signaling distal to AngII on the activation of type-1 plasminogen activator inhibitor (PAI-1) in the fibrinolytic process and subsequent formation of thrombosis remains unclarified. METHODS AND RESULTS: To determine whether AngIV would inhibit fibrinolysis via PAI-1 activation and promote thrombosis, we evaluated the degree of fibrinolysis in thrombosis models and investigated the roles of AT4R after vascular injury using IRAP knockout mice (IRAP(-/-)). In endothelial cells from control mice (WT; C57Bl6/J), both AngII and AngIV treatments increased PAI-1 mRNA expression in a dose-dependent manner, whereas the response was blunted in endothelial cells from IRAP(-/-) mice. FeCl(3)-induced thrombosis was suppressed in the carotid arteries of IRAP(-/-) mice when compared with WT mice. Similarly, in a model of carotid artery ligation and cuff placement, IRAP(-/-) mice demonstrated accelerated fibrinolysis 7 days after surgery and reduced occlusive thrombosis with negative remodeling at 28 days. CONCLUSIONS: AngIV-AT4R signaling has a key role in fibrinolysis and the subsequent formation of arterial thrombosis after vascular injury. AT4R may be a novel therapeutic target against cardiovascular disease.

Mechanical stretch enhances IL-8 production in pulmonary microvascular endothelial cells.

In patients with acute respiratory distress syndrome, mechanical over-distension of the lung by a large tidal volume causes further damage and inflammation, called ventilator-induced lung injury (VILI), however, it is unclear how mechanical stretch affects the cellular functions or morphology in human pulmonary microvascular endothelial cells (HPMVECs). IL-8 has been proposed to play an important role in the progression of VILI by activating neutrophils. We demonstrated that HPMVECs exposed to cyclic uni-axial stretch produce IL-8 protein with p38 activation in strain- and time-dependent manners. The IL-8 synthesis was not regulated by other signal transduction pathways such as ERK1/2, JNK, or stretch-activated Ca(2+) channels. Moreover, cyclic stretch enhanced IL-6 and monocyte chemoattractant protein-1 production and reoriented cell perpendicularly to the stretch axis accompanied by actin polymerization. Taken together, IL-8 production by HPMVECs due to excessive mechanical stretch may activate neutrophilic inflammation, which leads to VILI.

The effect of recombinant aminopeptidase A (APA) on hypertension in pregnant spontaneously hypertensive rats (SHRs).

BACKGROUND: We have tested the effects of aminopeptidase A (APA), MgSO(4) and various conventional antihypertensive drugs on hypertension in pregnant spontaneously hypertensive rats (SHRs) and examined the effects on both fetal heart and kidney. METHODS: We used recombinant human APA, which has been recently shown to work as an antihypertensive agent in SHRs (n=5). Each drug was administered from gestational day 10 to day 20 and each dose was increased daily up to 10 fold until the end of treatment except for MgSO(4) (n=5 per each group). Blood pressure (BP) was monitored and fetal kidneys and heart were histologically examined. RESULTS: The antihypertensive effects of the drugs were in the following order: hydralazine>aminopeptidase A and angiotensin receptor blockers (ARBs), candesartan>MgSO(4) and methyldopa. Microscopic examination showed that fetal exposure to candesartan is associated with poor proximal tubular differentiation in the kidney and that to MgSO(4) is associated with poor blood vessel formation in the heart, respectively. CONCLUSIONS: Our present study showed that APA is one of the candidates for antihypertensive agents in hypertension during pregnancy.

Microsomal triglyceride transfer protein gene polymorphism strongly influences circulating malondialdehyde-modified low-density lipoprotein.

Microsomal triglyceride transfer protein (MTP) plays a critical role in the assembly of lipoproteins. Therefore, we studied whether MTP gene polymorphisms are associated with atherosclerosis-promoting parameters, especially metabolic profiles and endothelial function, in healthy young men. One hundred one healthy men (mean age, 30.3 years) were studied. We analyzed the 2 promoter polymorphisms (-493G/T and -400A/T) of the MTP gene. Linkage disequilibrium analysis revealed a significant but incomplete linkage disequilibrium between the 2 polymorphisms (D' = 0.74). The -493T allele carriers (n = 26) showed marked increases in their levels of malondialdehyde-modified low-density lipoprotein (mean value, 135 vs 99 U/L in the G/G carriers; P = .003) and triglycerides (2.15 vs 1.16 mmol/L, P = .014), and reduced low-density lipoprotein particle size (259.2 vs 264.3 nm, P = .023), whereas there was no difference in apolipoproteins, insulin, adiponectin, homocysteine, folate, and endothelial function assessed using ultrasound measurement of brachial artery flow-mediated vasodilation. In contrast, the -400T allele carriers (n = 61) showed a reduced endothelial function (P = .044), accompanied by elevated apolipoprotein B levels in subjects with higher triglyceride levels. These results indicate that both promoter polymorphisms may be associated with the development of atherosclerosis and cardiovascular diseases, but that the mechanism responsible may be different.

Differentiation capacity of endothelial progenitor cells correlates with endothelial function in healthy young men.

BACKGROUND: Endothelial progenitor cells (EPCs) have been assumed to maintain vascular endothelial integrity, so the present study investigated whether the functional capacity of EPCs correlates with endothelial function in healthy young subjects, as has been confirmed in aged subjects with atherosclerotic disease. METHODS AND RESULTS: EPCs in 41 healthy, young male nonsmokers (age 33.1 +/-3.9 years, mean +/- SD) were characterized. The correlation between flow-mediated vasodilation (FMD) and the number of EPCs or the plasma concentrations of growth factors, such as vascular endothelial growth factor, did not reach statistical significance. However, FMD was significantly correlated with the EPC differentiation index, defined as the ratio of the number of EPCs to the total number of adherent cells (r=0.391, P=0.011) and the abundance of endothelial nitric oxide synthase mRNA (r=0.340, P=0.030). CONCLUSIONS: In healthy young men, despite a lack of correlation of the number or colony counts of EPCs, the ability of circulating progenitor cells to differentiate into an endothelial lineage is closely correlated with endothelial function. This cell function assay may serve as a novel biomarker for vascular function in healthy subjects in the pre-atherosclerotic stage.