Effects of Repeated Intravenous Administration of Dextrans,Water-soluble Macromolecules, in Rats.

We investigated the influence of repeated intravenous administration of dextrans (DEXs) to rats. Seven-week-old Sprague Dawley rats (6 males/group) were given intravenously 10% saline solutions of dextrans (DEXs), 40 kDa or 200-300 kDa, at a dose level of 5 mL/kg/day for 28 days and they were examined histopathologically. Another group (3 males/group) was administered saline in a similar manner and served as the control. Histopathological changes indicating accumulation of DEXs in the mononuclear phagocyte system (MPS) and the liver were noted in the treated groups. The incidence and severity of the findings were molecular weight-dependent, except for the lungs. These results are considered useful in interpreting data from preclinical studies, in which DEXs or their derivatives are administered as test or control substances.

Extent to which weight loss contributes to improving metabolic dysfunction-associated and metabolic and alcohol related/associated steatotic liver disease: a study on Japanese participants undergoing health checkups.

Introduction: The incidence of steatotic liver disease has increased in recent years. Thus, steatotic liver disease is a major public health issue in Japan. This study investigated the association between weight reduction and the remission of metabolic dysfunction-associated steatotic liver disease (MASLD)/Metabolic and alcohol related/associated liver disease (MetALD) in Japanese individuals undergoing health checkups. Methods: This retrospective observational study included 8,707 Japanese patients with MASLD/MetALD who underwent health checkups from May 2015 to March 2023. The participants were monitored for its remission at their subsequent visit. MASLD was diagnosed on abdominal ultrasonography and based on the presence of at least one of five metabolic abnormalities. The impact of body mass index (BMI) reduction on MASLD/MetALD remission was assessed via logistic regression analysis and using receiver operating characteristic curves. Results: Logistic regression analysis revealed that weight loss was significantly associated with MASLD/MetALD remission. Other factors including exercise habits and reduced alcohol consumption were significant predictors of MASLD/MetALD remission in the overall cohort and in male patients. The optimal BMI reduction cutoff values for MASLD/MetALD remission were 0.9 kg/m2 and 4.0% decrease in the overall cohort, 0.85 kg/m2 and 3.9% decrease in males, and 1.2 kg/m2 and 4.5% decrease in females. In participants with a BMI of 23 kg/m2, the cutoff values were 0.75 kg/m2 and 2.7% BMI reduction. Discussion: Weight reduction plays an important role in both MASLD and MetALD remission among Japanese individuals. That is, targeting specific BMI reduction is effective. This underscores the importance of targeted weight management strategies in preventing and managing MASLD/MetALD in the Japanese population.

Apolipoprotein CIII induces monocyte chemoattractant protein-1 and interleukin 6 expression via Toll-like receptor 2 pathway in mouse adipocytes.

OBJECTIVE: To examine the direct effect of apolipoprotein CIII (apoCIII) on adipokine expressions that are involved in obesity, insulin resistance, or metabolic syndrome. METHODS AND RESULTS: ApoCIII in triglyceride-rich lipoproteins is elevated in patients with obesity, insulin resistance, or metabolic syndrome. Its level is also associated with proinflammatory adipokines. Fully differentiated mouse 3T3L1 adipocytes were incubated with apoCIII. ApoCIII activated nuclear factor κB of 3T3L1 adipocytes and induced the expression of monocyte chemoattractant protein (MCP) 1 and interleukin (IL) 6. ApoCIII also activated extracellular signal-regulated kinase and p38. Mitogen-activated protein kinase kinase (MEK)-1 inhibitor PD98059, but not p38 inhibitor SB203580, inhibited apoCIII-induced upregulation of MCP-1 and IL-6. Previously, it was shown that apoCIII activates proinflammatory signals through toll-like receptor (TLR) 2. TLR2-blocking antibody abolished activation of nuclear factor κB and extracellular signal-regulated kinase induced by apoCIII and inhibited apoCIII-induced upregulation of MCP-1 and IL-6. ApoCIII also reduced adiponectin expression of 3T3L1 adipocytes, which was recovered by TLR2-blocking antibody. ApoCIII induced the expression of MCP-1 and IL-6 in TLR2-overexpressed human embryonic kidney 293 cells but not wild-type human embryonic kidney 293 cells without TLR2. ApoCIII induced the expression of MCP-1 and IL-6 and decreased adiponectin expression in white adipose tissue of wild-type mice but not of TLR2-deficient mice in vivo. CONCLUSIONS: ApoCIII may activate extracellular signal-regulated kinase and nuclear factor kB through TLR2 and induce proinflammatory adipokine expression in vitro and in vivo. Thus, apoCIII links dyslipidemia to inflammation in adipocytes, which, in turn, may contribute to atherosclerosis.

Toll-like receptor 2 mediates apolipoprotein CIII-induced monocyte activation.

Apolipoprotein (apo)CIII predicts risk for coronary heart disease. We recently reported that apoCIII directly activates human monocytes. Recent evidence indicates that toll-like receptor (TLR)2 can contribute to atherogenesis through transduction of inflammatory signals. Here, we tested the hypothesis that apoCIII activates human monocytoid THP-1 cells through TLR2. ApoCIII induced the association of TLR2 with myeloid differentiation factor 88, activated nuclear factor (NF)-kappaB in THP-1 cells, and increased their adhesion to human umbilical vein endothelial cells (HUVECs). Anti-TLR2 blocking antibody, but not anti-TLR4 blocking antibody or isotype-matched IgG, inhibited these processes (P<0.05). ApoCIII bound with high affinity to human recombinant TLR2 protein and showed a significantly higher (P<0.05) and saturable binding to 293 cells overexpressing human TLR2 than to parental 293 cells with no endogenous TLR2. Overexpression of TLR2 in 293 cells augmented apoCIII-induced NF-kappaB activation and beta(1) integrin expression, processes inhibited by anti-apoCIII antibody as well as anti-TLR2 antibody. Exposure of peripheral blood monocytes isolated from C57BL/6 (wild-type) mice to apoCIII activated their NF-kappaB and increased their adhesiveness to HUVECs. In contrast, apoCIII did not activate monocytes from TLR2-deficient mice. Finally, intravenous administration to C57BL/6 mice of apoCIII-rich very-low-density lipoprotein (VLDL), but not of apoCIII-deficient VLDL, activated monocytes and increased their adhesiveness to HUVECs, processes attenuated by anti-TLR2 or anti-apoCIII antibody. ApoCIII-rich VLDL did not activate monocytes from TLR2-deficient mice. In conclusion, apoCIII activated monocytes at least partly through a TLR2-dependent pathway. The present study identifies a novel mechanism for proinflammatory and proatherogenic effects of apoCIII and a role for TLR2 in atherosclerosis induced by atherogenic lipoproteins.

Apolipoprotein CIII links hyperlipidemia with vascular endothelial cell dysfunction.

BACKGROUND: Apolipoprotein CIII (apoCIII) is a component of some triglyceride-rich very-low-density and low-density lipoprotein and is elevated in dyslipidemia with insulin resistance and the metabolic syndrome. We previously reported that apoCIII directly activates proinflammatory and atherogenic signaling in vascular endothelial cells through protein kinase C-beta (PKCbeta). Because PKCbeta impairs the response of vascular endothelial cells to insulin, we tested the hypothesis that apoCIII affects insulin signaling in vascular endothelial cells and its function in vitro and in vivo. METHODS AND RESULTS: ApoCIII inhibited insulin-induced tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1), decreasing phosphatidylinositol 3-kinase (PI3K)/Akt activation in human umbilical vein endothelial cells. These effects of apoCIII led to reduced endothelial nitric oxide synthase (eNOS) activation and NO release into the media. ApoCIII activated PKCbeta in human umbilical vein endothelial cells, resulting in IRS-1 dysfunction via serine phosphorylation. ApoCIII also activated mitogen-activated protein kinase through PKCbeta. The impaired insulin signaling was restored by PKCbeta inhibitor or MEK1 inhibitor. ApoCIII-rich very-low-density lipoprotein and apoCIII impaired insulin signaling in the aorta of C57BL/6J mice and in human umbilical vein endothelial cells, which was recovered by PKCbeta inhibitor. They also inhibited endothelium-dependent relaxation of the aortas of C57BL/6J mice. In summary, apoCIII in very-low-density lipoprotein impaired insulin stimulation of NO production by vascular endothelium and induced endothelial dysfunction in vivo. This adverse effect of apoCIII was mediated by its activation of PKCbeta, which inhibits the IRS-1/PI3K/Akt/eNOS pathway. CONCLUSIONS: Our results suggest that apoCIII is a crucial link between dyslipidemia and insulin resistance in vascular endothelial cells with consequential deleterious effects on their atheroprotective functions.

Inhibition of hepatic Niemann-Pick C1-like 1 improves hepatic insulin resistance.

The present study attempted to define the role of hepatic Niemann-Pick C1-like 1 (NPC1L1), a cholesterol transporter, in hepatic insulin resistance as well as hepatic steatosis. The inhibition of NPC1L1 and its molecular consequences were examined in Zucker obese fatty (ZOF) rats and cultured steatotic hepatocytes using ezetimibe, a pharmacoloigcal inhibitor of NPC1L1, and short hairpin RNA (shRNA) of NPC1L1. Ezetimibe improved hepatic insulin signaling as well as hepatic steatosis in ZOF rats. It also restored insulin sensitivity in steatotic hepatocytes in vitro through a reduction in hepatic reactive oxygen species (ROS) generation, JNK activation, and ER stress. In addition, ezetimibe recovered insulin-induced Akt activation and reduced gluconeogenic genes in the liver of ZOF rats and cultured steatotic hepatocytes. Transfection of NPC1L1 shRNA into hepatocytes also reduced ROS generation and ER stress. These results indicate that NPC1L1 contributes to hepatic insulin resistance through cholesterol accumulation, and its inhibition could be a potential therapeutic target of hepatic insulin resistance.

Leptin inhibits and ghrelin augments hypothalamic noradrenaline release after stress.

Metabolic conditions affect hypothalamo-pituitary-adrenal responses to stressful stimuli. Here we examined effects of food deprivation, leptin and ghrelin upon noradrenaline release in the hypothalamic paraventricular nucleus (PVN) and plasma adrenocorticotropic hormone (ACTH) concentrations after stressful stimuli. Food deprivation augmented both noradrenaline release in the PVN and the increase in plasma ACTH concentration following electrical footshocks (FSs). An intracerebroventricular injection of leptin attenuated the increases in hypothalamic noradrenaline release and plasma ACTH concentrations after FSs, while ghrelin augmented these responses. These data suggest that leptin inhibits and ghrelin facilitates neuroendocrine stress responses via noradrenaline release and indicate that a decrease in leptin and an increase in ghrelin release after food deprivation might contribute to augmentation of stress-induced ACTH release in a fasting state.

Apolipoprotein CIII-induced THP-1 cell adhesion to endothelial cells involves pertussis toxin-sensitive G protein- and protein kinase C alpha-mediated nuclear factor-kappaB activation.

OBJECTIVE: Plasma apolipoprotein CIII (apoCIII) independently predicts risk for coronary heart disease (CHD). We recently reported that apoCIII directly enhances adhesion of human monocytes to endothelial cells (ECs), and identified the activation of PKC alpha as a necessary upstream event of enhanced monocyte adhesion. This study tested the hypothesis that apoCIII activates PKC alpha in human monocytic THP-1 cells, leading to NF-kappaB activation. METHODS AND RESULTS: Among inhibitors specific to PKC activators, phosphatidylcholine-specific phospholipase C (PC-PLC) inhibitor D609 limited apoCIII-induced PKC alpha activation and THP-1 cell adhesion. ApoCIII increased PC-PLC activity in THP-1 cells, resulting in PKC alpha activation. Pertussis toxin (PTX) inhibited apoCIII-induced PC-PLC activation and subsequent PKC alpha activation, implicating PTX-sensitive G protein pathway. ApoCIII further activated nuclear factor-kappaB (NF-kappaB) through PKC alpha in THP-1 cells and augmented beta1-integrin expression. The NF-kappaB inhibitor peptide SN50 partially inhibited apoCIII-induced beta1-integrin expression and THP-1 cell adhesion. ApoCIII-rich VLDL had similar effects to apoCIII alone. CONCLUSIONS: PTX-sensitive G protein pathway participates critically in PKC alpha stimulation in THP-1 cells exposed to apoCIII, activating NF-kappaB, and increasing beta1-integrin. This action causes monocytic cells to adhere to endothelial cells. Furthermore, because leukocyte NF-kappaB activation contributes to inflammatory aspects of atherogenesis, apoCIII may stimulate diverse inflammatory responses through monocyte activation.

Purification and biochemical characterization of a fibroblast growth factor-binding protein (FGF-BP) from the lactoferrin fraction of bovine milk.

By means of gel filtration on a TSK-gel HPLC column in the presence of 8 M urea, a 37-kDa polypeptide (p37) was completely separated from lactoferrin (LF) in the heparin HII fraction of the partially purified LF fraction prepared from bovine milk. Purified p37 was identified as a fibroblast growth factor-binding protein (FGF-BP), since its N-terminal 14 amino acid residues (KKEGRNRRGSKASA) were 100% identical to the corresponding sequence of bovine FGF-BP. It was found, in vitro, that (i) p37 had a higher binding affinity with bFGF than bLF; (ii) p37 functioned as a phosphate acceptor for at least three protein kinases (PKA, CK1 and CK2); (iii) bLF stimulated about 3-fold the PKA-mediated phosphorylation of p37, but suppressed its phosphorylation by CK1; and (iv) galloyl pedunculagin was an effective inhibitor for the phosphorylation of p37 by PKA and CK1. Furthermore, the physiological correlation between p37 and bLF may be regulated through specific phosphorylation of p37 by PKA, since p37 fully phosphorylated by PKA did not bind to bLF in vitro. The sulfatide-induced conformational changes in p37 enabled the phosphorylation of p37 by CK1 and also reduced its ability to bind with bLF in vitro. From these results presented here, it is concluded that (i) p37 (FGF-BP) may be tightly associated with bLF in bovine milk; and (ii) the physiological correlation between p37 and bLF may be regulated by the PKA-mediated full phosphorylation of p37 or by the direct binding of sulfatide to p37 in vivo.

Apolipoprotein CIII induces expression of vascular cell adhesion molecule-1 in vascular endothelial cells and increases adhesion of monocytic cells.

BACKGROUND: Activation of vascular endothelial cells (ECs) plays an important role in atherogenesis and plaque instability. Lipoproteins containing apolipoprotein CIII (apoCIII) predict coronary heart disease (CHD). We recently reported that apoCIII has a proinflammatory effect on human monocytes. In this study, we looked for a direct effect of apoCIII on EC expression of adhesion molecules, leading to monocytic cell adhesion. METHODS AND RESULTS: Treatment of ECs with apoCIII or apoCIII-rich VLDL caused human monocytic THP-1 cells to adhere to them under static condition or under laminar sheer stress (1.0 dyne/cm2). ApoCIII increased EC expression of vascular cell adhesion molecule-1 (VCAM-1) protein and intercellular cell adhesion molecule-1 (ICAM-1) protein (4.9 +/- 1.5-fold and 1.4 +/- 0.5-fold versus control, respectively). Furthermore, apoCIII remarkably increased membrane-bound protein kinase C (PKC) beta in ECs, indicating activation. A selective inhibitor of PKCbeta prevented the rise in VCAM-1 and THP-1 cell adhesion to ECs. Moreover, exposure of ECs to apoCIII induced nuclear factor-kappaB (NF-kappaB) activation. PKCbeta inhibition abolished apoCIII-induced NF-kappaB activation, and NF-kappaB inhibition reduced expression of VCAM-1, each resulting in reduced THP-1 cell adhesion. ApoCIII-rich VLDL also activated PKCbeta and NF-kappaB in ECs and increased expression of VCAM-1. Pretreatment of ApoCIII-rich VLDL with anti-apoCIII neutralizing antibody abolished its effect on PKCbeta activation. CONCLUSIONS: Our findings provide the first evidence that apoCIII increases VCAM-1 and ICAM-1 expression in ECs by activating PKCbeta and NF-kappaB, suggesting a novel mechanism for EC activation induced by dyslipidemia. Therefore, apoCIII-rich VLDL may contribute directly to atherogenesis by activating ECs and recruiting monocytes to them.

Apolipoprotein CIII in apolipoprotein B lipoproteins enhances the adhesion of human monocytic cells to endothelial cells.

BACKGROUND: Lipoproteins containing apolipoprotein (apo) CIII predict coronary heart disease and associate with components of the metabolic syndrome. ApoCIII inhibits lipoprotein catabolism in plasma. However, it is unknown whether apoCIII itself, or in association with VLDL, LDL, or HDL, directly affects atherogenic mechanisms in vascular cells. Thus, we investigated the direct effect of lipoproteins that do or do not have apoCIII, and apoCIII itself, on adhesion of THP-1 cells, a human monocytic cell line, to vascular endothelial cells (ECs). METHODS AND RESULTS: VLDL CIII+ and LDL CIII+ (100 microg apoB/mL) from fasting plasma of 18 normolipidemic volunteers increased THP-1 cell adhesion to ECs under static conditions by 2.4+/-0.3-fold and 1.8+/-0.7-fold, respectively (P<0.01), whereas VLDL or LDL without apoCIII did not affect THP-1 cell adhesion. ApoCIII (100 microg/mL), but not apoCI, apoCII or apoE, also increased THP-1 cell adhesion by 2.1+/-0.6-fold. Studies with human peripheral blood monocytes yielded similar results. ApoCIII also had strong proadhesive effects under shear flow conditions. VLDL CIII+, LDL CIII+, or apoCIII itself activated PKCalpha and RhoA in THP-1 cells, which resulted in beta1-integrin activation and enhancement of THP-1 cell adhesion. Interestingly, HDL CIII+ did not affect THP-1 cell adhesion, whereas HDL without apoCIII decreased their adhesion. CONCLUSIONS: ApoB lipoproteins that contain apoCIII increase THP-1 cell adhesion to ECs via PKCalpha and RhoA-mediated beta1-integrin activation. These results indicate that apoCIII not only modulates lipoprotein metabolism but also may directly contribute to the development of atherosclerosis.

Sphingosine 1-phosphate (S1P) inhibits monocyte-endothelial cell interaction by regulating of RhoA activity.

Recent studies suggest that sphingosine 1-phosphate (S1P) protects against atherosclerosis. We assessed the effects of S1P on monocyte-endothelial interaction in the presence of inflammatory mediators. Pretreatment of THP-1 cells with S1P abolished Phorbol 12 myristate 13-acetate (PMA)-induced THP-1 cell adhesion to human umbilical vein endothelial cells (HUVECs). S1P inhibited PMA-induced activation of RhoA, but not PKCs. S1P activated p190Rho GTPase activation protein (GAP) only in the presence of PMA, suggesting an inhibitory effect of S1P and PMA to suppress RhoA. In conclusion, S1P inhibited monocyte-endothelial interactions by inhibiting RhoA activity which may explain its anti-atherogenic effects.

Ezetimibe improves liver steatosis and insulin resistance in obese rat model of metabolic syndrome.

Non-alcoholic fatty liver disease (NAFLD) is associated with the metabolic syndrome characterized by dislipidemia and insulin resistance. We hypothesized that ezetimibe, an inhibitor of NPC1L1, improves these metabolic disorders in Zucker obese fatty rats (ZOF). Ezetimibe significantly lowered total cholesterol and triglycerides in ZOF with prominent reduction in the remnant lipoprotein fraction and small dense low density lipoprotein fraction. Moreover, lipid deposition and fibrosis of liver were decreased by ezetimibe. Interestingly, ezetimibe improved insulin and plasma glucose response after intraperitoneal glucose injection. Further, ezetimibe enhanced insulin signaling in cultured hepatocytes. Our results indicate the potential of ezetimibe in treating the metabolic syndrome and NAFLD.

Angiotensin-converting enzyme inhibitor attenuates monocyte adhesion to vascular endothelium through modulation of intracellular zinc.

To elucidate an anti-inflammatory role of angiotensin-converting enzyme inhibitors (ACEIs) in cardiovascular disease, we studied the effect of ACEIs in monocyte adhesion to endothelial cells and underlying molecular mechanisms. Treatment of human monocytic THP-1 cells with monocyte chemoattractant protein-1 (MCP-1; 100 ng/ml; 10 min) significantly increased their adhesion to human umbilical vein endothelial cells (HUVECs) under flow condition (P < 0.001). Preincubation of THP-1 cells with imidaprilat (50 nM; 4 h), an active metabolite of imidapril, reduced MCP-1-triggered THP-1 cell adhesion (P < 0.01). Similar effects were obtained with experiments using human peripheral monocytes (P < 0.05). MCP-1 activated protein kinase C (PKC)alpha in THP-1 cells, resulting in the up-regulation of alpha4 and beta2 integrin. Imidaprilat attenuated MCP-1-induced PKC activation and integrin up-regulation in THP-1 cells. Imidaprilat also inhibited THP-1 cell adhesion induced by phorbol 12-myristate 13-acetate (PMA), a potent PKC activator. In attempt to elucidate the mechanisms for the modulation of PKC activity by imidaprilat, we found that MCP-1 or PMA increased labile zinc in THP-1 cells, which was canceled by imidaprilat. Indeed, zinc/pyrithione activated PKC and increased THP-1 cell adhesion. Zinc chelator as well as PKC inhibitor inhibited these processes, suggesting the role for labile zinc in PKC activation and THP-1 cell adhesion. Imidaprilat attenuated zinc/pyrithione-induced PKC activation and THP-1 cell adhesion. These data suggest that ACEI reduces MCP-1 or PMA-triggered monocyte adhesion to activated HUVECs by modulating labile zinc in monocytes. Our findings may point out a novel anti-inflammatory mechanism of ACEIs in atherogenesis.

Hepatocyte growth factor fusion protein having collagen-binding activity (CBD-HGF) accelerates re-endothelialization and intimal hyperplasia in balloon-injured rat carotid artery.

AIM: Hepatocyte growth factor (HGF) is known to stimulate endothelial cell proliferation. However, re-endothelialization is not enhanced when the native protein is administered to the injured artery, probably due to the short half-life of HGF at the site of injury. Therefore, the effects of an HGF fusion protein having collagen-binding activity (CBD-HGF) on re-endothelialization and neointimal formation was studied in the balloon-injured rat carotid artery. METHODS: The left common carotid artery of male Sprague-Dawley rats was injured with an inflated balloon catheter, and then treated with CBD-HGF 10 microg/mL), HGF (10 micro g/mL) or saline (control) for 15 min. After 14 days, the rats were injected with Evans blue and sacrificed. RESULTS: The re-endothelialized area was significantly greater in the CBD-HGF- treated rats than in the control or HGF -treated rats. Neointimal formation was significantly more pronounced in the CBD-HGF treated rats than in other rat groups. Both HGF and CBD-HGF stimulated proliferation of vascular smooth muscle cells as well as endothelial cells in vitro. Consistent with this, cultured smooth muscle cells were shown to express the HGF receptor (c-Met). CONCLUSION: CBD-HGF accelerates re-endothelialization and neointimal formation in vivo. CBD fusion protein is a useful vehicle to deliver vascular growth factors to injured arteries.

A novel contrast medium detects increased permeability of rat injured carotid arteries in magnetic resonance T2 mapping imaging.

AIM: Aim of this study was to directly detect increased permeability of vascular lesions by magnetic resonance imaging. METHODS: A novel contrast medium with a mean hydrodynamic diameter of 100 nm was prepared from monodispersed iron colloids incorporated into micelles of block copolymers composed of polyethylene glycol and polyamino acid. T2 mapping was applied to differentiate the minimal shortening of T2 relaxation time in balloon-injured rat carotid arteries. RESULTS: The novel contrast medium accumulated in deendothelialized arteries. T2 relaxation times of injured and uninjured arteries were 50.6 +/- 9.5 ms and 26.9 +/- 2.4 ms, respectively (the mean +/- SD, p< 0.01, n=5). The novel contrast medium, but not commercially available contrast media, shortened the T2 relaxation time of the injured artery to 35.5 +/- 9.7 ms (p< 0.01, n=4). CONCLUSION: A novel iron contrast medium enhanced the lesions with increased permeability. The contrast medium in combination with T2 mapping may be useful to detect unstable atherosclerotic plaques.

[An elderly case of hyperglycemic hyperosmolar non-ketotic coma (HHNC)].

A 79-year old woman was admitted with disturbed consciousness (JCS II-30). She had been given a diagnosis of type 2 diabetes 7 years previously, and was being treated with oral hypoglycemic agents. She also suffered Alzheimer's disease and Parkinson's disease. Plasma glucose and HbA1c upon admission was 676mg/dl and 9.7%, respectively. Serum Na was 153mEq/l. Urine ketone body test was negative and metabolic acidosis was not observed. Hyperglycemic hyperosmolar non-ketotic coma (HHNC) was diagnosed, and treatment was started immediately with normal saline infusion. Continuous infusion of regular insulin was needed to lower blood glucose. Disturbed consciousness and dehydration improved by the third hospital day. However, she became bedridden afterwards and received tube feeding. Up to 46 units of insulin was needed daily to control blood glucose. Urine C-peptide secretion was very low (10microg/day), suggesting that insulin therapy was essential for glycemic control long before admission. It is thought that a number of elderly diabetic patients who need insulin therapy do not receive or continue it for various reasons. Discussion is necessary to grasp the actual situation and defensive actions that can be taken.

Atorvastatin attenuates remnant lipoprotein-induced monocyte adhesion to vascular endothelium under flow conditions.

Remnant lipoproteins have been reported to play a causative role in atherogenesis. We investigated the effect of remnant-like lipoprotein particles (RLPs) on monocyte-endothelial interaction and their potential regulation by atorvastatin. Monocytic U937 cells were incubated with RLPs isolated from hypertriglyceridemia subjects and their adhesion to human umbilical vein endothelial cells (HUVECs) was examined under flow conditions. Incubation of U937 cells with 15 micro g protein/mL RLPs increased their adhesion to HUVECs activated with IL-1beta (untreated: 6.8+/-1.6 cells/HPF versus RLPs: 16.2+/-3.3 cells/HPF, P<0.05). Flow cytometric analysis revealed that incubation with RLPs increased expression levels of CD11a, CD18, and CD49d in U937 cells. Moreover, RLP-induced RhoA activation as well as FAK activation was seen in U937 cells, and RLP-induced RhoA activation seemed to be involved with PKC-dependent signaling. To explore the effect of atorvastatin on RLP-induced U937 cell adhesion to HUVECs, U937 cells were incubated with RLPs in the presence of atorvastatin. Pretreatment of U937 cells with 10 micro mol/L atorvastatin significantly decreased RLP-induced U937 cell adhesion to activated HUVECs (RLP 15.2+/-1.5 cells/HPF versus atorvastatin+RLP 10.2+/-1.0 cells/HPF; P<0.05) and decreased the enhanced integrin expression in RLP-treated U937 cells. Atorvastatin also inhibited RLP-induced RhoA activation and FAK activation in U937 cells. In summary, RLPs induced monocyte adhesion to vascular endothelium by sequential activation of PKC, RhoA, FAK, and integrins, indicating a role of remnant lipoproteins in vascular inflammation during atherogenesis. Atorvastatin attenuated this enhanced monocyte adhesion to HUVECs, suggesting an antiinflammatory role for this compound.

Pitavastatin inhibits remnant lipoprotein-induced macrophage foam cell formation through ApoB48 receptor-dependent mechanism.

OBJECTIVE: Atherogenic remnant lipoproteins (RLPs) are known to induce foam cell formation in macrophages in vitro and in vivo. We examined the involvement of apoB48 receptor (apoB48R), a novel receptor for RLPs, in that process in vitro and its potential regulation by pitavastatin. METHODS AND RESULTS: THP-1 macrophages were incubated in the presence of RLPs (20 mg cholesterol/dL, 24 hours) isolated from hypertriglyceridemic subjects. RLPs significantly increased intracellular cholesterol ester (CE) and triglyceride (TG) contents (4.8-fold and 5.8-fold, respectively) in the macrophages. Transfection of THP-1 macrophages with short interfering RNA (siRNA) against apoB48R significantly inhibited RLP-induced TG accumulation by 44%. When THP-1 macrophages were pretreated with pitavastatin (5 micromol/L, 24 hours), the expression of apoB48R was significantly decreased and RLP-induced TG accumulation was reduced by 56%. ApoB48R siRNA also inhibited TG accumulation in THP-1 macrophage induced by beta-very-low-density lipoprotein derived from apoE-/- mice by 58%, supporting the notion that apoB48R recognizes and takes-up RLPs in an apoE-independent manner. CONCLUSIONS: RLPs induce macrophage foam cell formation via apoB48R. Pitavastatin inhibits RLP-induced macrophage foam cell formation. The underlying mechanism involves, at least in part, inhibition of apoB48R-dependent mechanism. Our findings indicate a potential role of apoB48R in atherosclerosis. RLPs induced macrophage foam cell formation via apoB48R. Pitavastatin inhibited RLP-induced macrophage foam cell formation, at least in part, via inhibition of apoB48R expression. Our findings indicate a potential role of apoB48R in atherosclerosis.