BT2 Suppresses Human Monocytic-Endothelial Cell Adhesion, Bone Erosion and Inflammation.

INTRODUCTION: Inflammation and bone erosion are processes key to the pathogenesis of rheumatoid arthritis, a systemic autoimmune disease causing progressive disability and pain, impacting around 1.3 million people in the United States alone. However, many patients do not respond sufficiently to existing therapies or benefit is not sustained and alternate therapeutic approaches are lacking. We recently identified the dibenzoxazepinone BT2, which inhibits ERK phosphorylation, from a high-throughput chemical screen and identified its ability to inhibit angiogenesis and vascular leakiness. METHODS: Here we evaluated BT2 for potential anti-inflammatory activity in in vitro models of human monocytic-endothelial cell adhesion, monocytic cell extravasation and collagen antibody-induced arthritis in mice. RESULTS: BT2 inhibits human monocytic cell adhesion to IL-1ß-treated human endothelial cells and inhibits monocytic transendothelial migration toward MCP-1. In mice rendered arthritic, single systemic administration of BT2 prevented footpad swelling, bone destruction and TRAP+ cells in the joints. BT2 suppressed inducible circulating levels of IL-1ß, IL-2 and IL-6 to normal levels without affecting levels of IL-4 or IL-10 among other cytokines. BT2 also inhibited the expression of pro-inflammatory adhesion molecules ICAM-1 and VCAM-1 in arthritic joints. There was no evidence of toxicity following intraperitoneal, gavage or intraarticular administration of BT2. CONCLUSION: BT2 is a novel small molecule inhibitor of joint inflammation, bone erosion, pro-inflammatory cytokine and adhesion molecule expression. This suggests the potential clinical utility of BT2 as a new anti-inflammatory agent.

Relationship of fibroblast growth factor 21 levels with inflammation, lipoproteins and non-alcoholic fatty liver disease.

BACKGROUND AND AIMS: Non-alcoholic fatty liver disease (NAFLD) is associated with inflammation and atherogenic lipoprotein abnormalities. Previous studies suggest an association of fibroblast growth factor 21 (FGF21) with NAFLD. Therefore, we assessed the association of circulating FGF21 levels with inflammatory markers, lipoprotein profile and NAFLD in the Multi-Ethnic Study of Atherosclerosis (MESA). METHODS: Among 6814 participants free of apparent cardiovascular disease at baseline (2000-2002), 3634 participants had valid data on variables of interest. After excluding participants with excessive alcohol consumption, 3446 participants were included in the analysis. NAFLD was defined using non-contrast cardiac computed tomography with a liver-to-spleen ratio (LSR) < 1 or liver attenuation <40 Hounsfield units (HU). RESULTS: The mean age of the participants was 63.5 years with 54% females, 36% Caucasian, 10% Chinese American, 31% African American and 23% Hispanic. 17% of the participants had NAFLD. After adjustment for demographic, socioeconomic and other confounders, a 1-SD increment in ln-transformed FGF21 level was associated with a 5.1% higher IL-6 level, a 0.31 nm larger very-low-density lipoprotein particle diameter, a 0.014 nm smaller high-density lipoprotein particle diameter, and a 5.25 nmol/L lower intermediate-density lipoprotein particle concentration (all p < 0.05). A 1-SD increment in ln-transformed FGF21 level was associated with LSR<1 and liver attenuation <40 HU (OR = 1.38 and 1.48; both p < 0.01), even after adjusting for the aforementioned inflammation and lipoprotein parameters. CONCLUSIONS: This study suggests an association between FGF21 and NAFLD, independent of inflammation and atherogenic lipoprotein abnormalities. Further studies are needed to assess FGF21 as a biomarker for future NAFLD risk.

The Cholesteryl Ester Transfer Protein Inhibitor, des-Fluoro-Anacetrapib, Prevents Vein Bypass-induced Neointimal Hyperplasia in New Zealand White Rabbits.

Coronary artery bypass grafting is among the most commonly performed of all cardiovascular surgical procedures. However, graft failure due to stenosis reduces the long-term benefit of the intervention. This study asks if elevating plasma high density lipoprotein cholesterol (HDL-C) levels by inhibition of cholesteryl ester transfer protein (CETP) activity with des-fluoro-anacetrapib, an analog of the CETP inhibitor anacetrapib, prevents vein bypass-induced neointimal hyperplasia. NZW rabbits were placed on a normal chow diet or chow containing 0.14% (wt/wt) des-fluoro-anacetrapib for 6 weeks. Bypass grafting of the jugular vein to the common carotid artery was performed 2 weeks after starting dietary des-fluoro-anacetrapib supplementation. The animals were euthanised 4 weeks post-bypass grafting. Relative to control, dietary supplementation with des-fluoro-anacetrapib reduced plasma CETP activity by 89 ± 6.9%, increased plasma apolipoprotein A-I levels by 24 ± 5.5%, increased plasma HDL-C levels by 93 ± 26% and reduced intimal hyperplasia in the grafted vein by 38 ± 6.2%. Des-fluoro-anacetrapib treatment was also associated with decreased bypass grafting-induced endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), endothelial dysfunction, and smooth muscle cell (SMC) proliferation in the grafted vein. In conclusion, increasing HDL-C levels by inhibiting CETP activity is associated with inhibition of intimal hyperplasia in grafted veins, reduced inflammatory responses, improved endothelial function, and decreased SMC proliferation.

Relationship of fibroblast growth factor 21 with subclinical atherosclerosis and cardiovascular events: Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: Fibroblast growth factor 21 (FGF21) has been suggested as a novel biomarker for cardiovascular disease (CVD), especially in people with high CVD risk. However, it is not known whether FGF21 is a CVD biomarker in an initially healthy cohort. We therefore investigated the relationship of plasma FGF21 levels with measures of subclinical atherosclerosis and cardiovascular events in Multi-Ethnic Study of Atherosclerosis participants without known CVD at baseline. METHODS: A total of 5788 participants had plasma FGF21 levels measured at the baseline exam (2000-2002). Carotid intima-media thickness (IMT), ankle-brachial index (ABI) and coronary artery calcification (CAC) were measured at baseline. Participants were followed up for incident CVD events over a median period of 14 years. RESULTS: In cross-sectional analyses adjusting for socio-demographic variables, participants with higher FGF21 levels had higher carotid IMT, lower ABI, and higher prevalence of CAC (p < 0.001). However, these associations were not significant after simultaneously adjusting for demographic, socioeconomic and lifestyle factors, traditional CVD risk factors, and biomarkers of inflammation and hemostasis. Among 5768 patients with follow-up data, 820 developed incident CVD endpoints. Higher baseline FGF21 levels were not associated with the risk for incident CVD endpoints after adjusting for multiple confounding factors (odds ratio 1.03; 95% confidence interval, 0.94-1.12, per SD increase in ln-transformed FGF21 levels). CONCLUSIONS: Although FGF21 has been suggested as a CVD biomarker for people with high CVD risk, our findings do not support a role of FGF21 as a CVD biomarker in those without a history of CVD.

Apolipoprotein A-I improves pancreatic ß-cell function independent of the ATP-binding cassette transporters ABCA1 and ABCG1.

Apolipoprotein A-I (apoA-I), the main protein constituent of HDLs, increases insulin synthesis and insulin secretion in pancreatic ß cells. ApoA-I also accepts cholesterol that effluxes from cells expressing ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1). Mice with conditional deletion of ABCA1 and ABCG1 in ß cells [ß-double knockout (DKO) mice] have increased islet cholesterol levels and reduced glucose-stimulated insulin secretion (GSIS). The project asks whether metabolic pathways are dysregulated in ß-DKO mouse islets and whether this can be corrected, and GSIS improved, by treatment with apoA-I. ß-DKO mice were treated with apoA-I or PBS, and islets were isolated for determination of GSIS. Total RNA was extracted from ß-DKO and control mouse islets for microarray analysis. Metabolic pathways were interrogated by functional enrichment analysis. ApoA-I treatment improved GSIS in ß-DKO but not control mouse islets. Plasma lipid and lipoprotein levels and islet cholesterol levels were also unaffected by treatment with apoA-I. Cholesterol metabolism, glucose metabolism, and inflammation pathways were dysregulated in ß-DKO mouse islets. This was not corrected by treatment with apoA-I. In summary, apoA-I treatment improves GSIS by a cholesterol-independent mechanism, but it does not correct metabolic dysregulation in ß-DKO mouse islets.-Hou, L., Tang, S., Wu, B. J., Ong, K.-L., Westerterp, M., Barter, P. J., Cochran, B. J., Tabet, F., Rye, K.-A. Apolipoprotein A-I improves pancreatic ß-cell function independent of the ATP-binding cassette transporters ABCA1 and ABCG1.

Apolipoprotein A-I Protects Against Pregnancy-Induced Insulin Resistance in Rats.

Objective- Insulin resistance and inflammation in pregnancy are risk factors for gestational diabetes mellitus. Increased plasma HDL (high-density lipoprotein) and apo (apolipoprotein) A-I levels have been reported to improve glucose metabolism and inhibit inflammation in animals and humans. This study asks whether increasing plasma apoA-I levels improves insulin sensitivity and reduces inflammation in insulin-resistant pregnant rats. Approach and Results- Insulin-resistant pregnant rats received intravenous infusions of lipid-free apoA-I (8 mg/kg) or saline on days 6, 9, 12, 15, and 18 of pregnancy. The rats were then subjected to a euglycemic-hyperinsulinemic clamp. Glucose uptake was increased in white and brown adipose tissue by 57±13% and 32±10%, respectively ( P<0.05 for both), and in quadriceps and gastrocnemius muscle by 35±9.7% and 47±14%, respectively ( P<0.05 for both), in the apoA-I-treated pregnant rats relative to saline-infused pregnant rats. The pregnant rats that were treated with apoA-I also had reduced plasma TNF-α (tumor necrosis factor-α) levels by 57±8.4%, plasma IL (interleukin)-6 levels by 67±9.5%, and adipose tissue macrophage content by 54±8.2% ( P<0.05 for all) relative to the saline-treated pregnant rats. Conclusions- These studies establish that apoA-I protects against pregnancy-induced insulin resistance in rats by increasing insulin sensitivity in adipose tissue and skeletal muscle and inhibiting inflammation. This identifies apoA-I as a potential target for preventing pregnancy-induced insulin resistance and reducing the incidence of gestational diabetes mellitus.

Apolipoprotein A-I enhances insulin-dependent and insulin-independent glucose uptake by skeletal muscle.

Therapeutic interventions that increase plasma high density lipoprotein (HDL) and apolipoprotein (apo) A-I levels have been reported to reduce plasma glucose levels and attenuate insulin resistance. The present study asks if this is a direct effect of increased glucose uptake by skeletal muscle. Incubation of primary human skeletal muscle cells (HSKMCs) with apoA-I increased insulin-dependent and insulin-independent glucose uptake in a time- and concentration-dependent manner. The increased glucose uptake was accompanied by enhanced phosphorylation of the insulin receptor (IR), insulin receptor substrate-1 (IRS-1), the serine/threonine kinase Akt and Akt substrate of 160 kDa (AS160). Cell surface levels of the glucose transporter type 4, GLUT4, were also increased. The apoA-I-mediated increase in glucose uptake by HSKMCs was dependent on phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt, the ATP binding cassette transporter A1 (ABCA1) and scavenger receptor class B type I (SR-B1). Taken together, these results establish that apoA-I increases glucose disposal in skeletal muscle by activating the IR/IRS-1/PI3K/Akt/AS160 signal transduction pathway. The findings suggest that therapeutic agents that increase apoA-I levels may improve glycemic control in people with type 2 diabetes.

Fibroblast growth factor 21 in chronic kidney disease.

The association between fibroblast growth factor 21 (FGF21) and kidney function has been extensively studied in recent years in both animal and human studies. However, the exact functional role of FGF21 in the kidney remains unclear. Previous animal studies have shown that administration of FGF21 ameliorates kidney function, morphological glomerular abnormalities, dyslipidemia, hyperglycemia, insulin resistance, oxidative stress and obesity. In human studies, FGF21 levels negatively correlated with estimated glomerular filtration rate. FGF21 levels were elevated in patients with end-stage renal disease. The elevation of FGF21 levels in presence of kidney disease has also raised questions as to whether FGF21 is a potential biomarker for detecting a decline in renal function. In recent clinical trials, an FGF21 analogue reduced insulin levels and body weight, and ameliorated dyslipidemia in patients with type 2 diabetes mellitus and obesity, all of which are well-known risk factors for kidney disease. Thus, FGF21 may be a potential therapeutic target for the treatment of kidney disease, although adverse side effects should also be considered when administering FGF21 since FGF21 may affect bone development and reproduction. This review will assess current knowledge on the relationship between FGF21 and kidney function.

Role of fibroblast growth factor 21 in gestational diabetes mellitus: A mini-review.

Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first diagnosis during pregnancy, but not to the level of being diagnostic for diabetes in a nonpregnant adult. In GDM, whole-body insulin-dependent glucose disposal decreases by 40%-60% which necessitates a 200%-250% increase in insulin secretion to maintain normoglycaemia. GDM develops when a pregnant woman does not produce sufficient insulin to compensate for the reduced glucose disposal. Fibroblast growth factor 21 (FGF21) is a hormone that is expressed predominantly in the liver, but also in other metabolically active tissues such as pancreas, skeletal muscle and adipose tissue. In animals, FGF21 lowers blood glucose levels and inhibits glucagon secretion. In humans, circulating FGF21 levels are increased in insulin-resistant morbidities such as obesity and type 2 diabetes mellitus (T2DM). An elevated FGF21 level is also an independent predictor of T2DM. GDM and T2DM are proposed to have similar underlying pathophysiologies, raising the question of whether a similar relationship exists between FGF21 and GDM as it does with T2DM. There are a limited number of studies investigating FGF21 levels in patients with GDM. Moreover, recent clinical trials investigating the therapeutic potential of FGF21 have highlighted a major gap in our understanding of the biology of FGF21. This review evaluates what is currently known about FGF21 and GDM and highlights important gaps that warrant further research.

Association of elevated circulating fibroblast growth factor 21 levels with prevalent and incident metabolic syndrome: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: Fibroblast growth factor 21 (FGF21) plays an important role in glucose and lipid metabolism. We have investigated the relationship of plasma FGF21 levels with both prevalent and incident metabolic syndrome (MetS) in participants from the Multi-Ethnic Study of Atherosclerosis (MESA). METHODS: 5783 participants from four major ethnic groups (non-Hispanic white, African American, Hispanic American, and Chinese American) were included in the cross-sectional analysis. Longitudinal analysis involved 3479 participants without MetS at baseline, of whom 1100 participants developed incident MetS over 9.2 years. RESULTS: Elevated FGF21 levels were found in participants with prevalent MetS (median [interquartile range] = 189.4 [114.4-302.1] vs. 123.7 [65.9-210.3] pg/mL, p < 0.001) or incident MetS (145.6 [84.9-240.8] vs 112.0 [57.0-194.5] pg/mL, p < 0.001), compared to those without. After adjusting for baseline demographic, socioeconomic and lifestyle factors, as well as cardiovascular risk factors and biomarkers, and compared to the lowest quartile, the highest FGF21 quartile was associated with prevalent MetS (odds ratio 2.80; 95% confidence interval, 2.30-3.40, p < 0.001). Among participants without MetS at baseline, the highest FGF21 quartile was associated with higher risk of incident MetS (hazards ratio 1.76; 95% confidence interval, 1.46-2.12, p < 0.001). Similar results were obtained when assessing ln-transformed FGF21 levels. Overall, no significant interaction was found with age, sex, and race/ethnicity for both prevalent and incident MetS. CONCLUSIONS: Higher FGF21 levels significantly predict the development of MetS in an ethnically diverse population followed long term. Further studies are needed to confirm the potential role of FGF21 as a biomarker for MetS.

Cholesteryl ester transfer protein and its inhibitors.

Most of the cholesterol in plasma is in an esterified form that is generated in potentially cardioprotective HDLs. Cholesteryl ester transfer protein (CETP) mediates bidirectional transfers of cholesteryl esters (CEs) and triglycerides (TGs) between plasma lipoproteins. Because CE originates in HDLs and TG enters the plasma as a component of VLDLs, activity of CETP results in a net mass transfer of CE from HDLs to VLDLs and LDLs, and of TG from VLDLs to LDLs and HDLs. As inhibition of CETP activity increases the concentration of HDL-cholesterol and decreases the concentration of VLDL- and LDL-cholesterol, it has the potential to reduce atherosclerotic CVD. This has led to the development of anti-CETP neutralizing monoclonal antibodies, vaccines, and antisense oligonucleotides. Small molecule inhibitors of CETP have also been developed and four of them have been studied in large scale cardiovascular clinical outcome trials. This review describes the structure of CETP and its mechanism of action. Details of its regulation and nonlipid transporting functions are discussed, and the results of the large scale clinical outcome trials of small molecule CETP inhibitors are summarized.

Effect of long-term dietary sphingomyelin supplementation on atherosclerosis in mice.

Sphingomyelin (SM) levels in the circulation correlate positively with atherosclerosis burden. SM is a ubiquitous component of human diets, but it is unclear if dietary SM increases circulating SM levels. Dietary choline increases atherosclerosis by raising circulating trimethylamine N-oxide (TMAO) levels in mice and humans. As SM has a choline head group, we ask in this study if dietary SM accelerates atherosclerotic lesion development by increasing circulating SM and TMAO levels. Three studies were performed: (Study 1) C57BL/6 mice were maintained on a high fat diet with or without SM supplementation for 4 weeks prior to quantification of serum TMAO and SM levels; (Study 2) atherosclerosis was studied in apoE-/- mice after 16 weeks of a high fat diet without or with SM supplementation and (Study 3) apoE-/- mice were maintained on a chow diet for 19 weeks without or with SM supplementation and antibiotic treatment prior to quantification of atherosclerotic lesions and serum TMAO and SM levels. SM consumption did not increase circulating SM levels or atherosclerosis in high fat-fed apoE-/- mice. Serum TMAO levels in C57BL/6 mice were low and had no effect atherosclerosis lesion development. Dietary SM supplementation significantly reduced atherosclerotic lesion area in the aortic arch of chow-fed apoE-/- mice. This study establishes that dietary SM does not affect circulating SM levels or increase atherosclerosis in high fat-fed apoE-/- mice, but it is anti-atherogenic in chow-fed apoE-/- mice.

Reduction of In-Stent Restenosis by Cholesteryl Ester Transfer Protein Inhibition.

OBJECTIVE: Angioplasty and stent implantation, the most common treatment for atherosclerotic lesions, have a significant failure rate because of restenosis. This study asks whether increasing plasma high-density lipoprotein (HDL) levels by inhibiting cholesteryl ester transfer protein activity with the anacetrapib analog, des-fluoro-anacetrapib, prevents stent-induced neointimal hyperplasia. APPROACH AND RESULTS: New Zealand White rabbits received normal chow or chow supplemented with 0.14% (wt/wt) des-fluoro-anacetrapib for 6 weeks. Iliac artery endothelial denudation and bare metal steel stent deployment were performed after 2 weeks of des-fluoro-anacetrapib treatment. The animals were euthanized 4 weeks poststent deployment. Relative to control, dietary supplementation with des-fluoro-anacetrapib reduced plasma cholesteryl ester transfer protein activity and increased plasma apolipoprotein A-I and HDL cholesterol levels by 53±6.3% and 120±19%, respectively. Non-HDL cholesterol levels were unaffected. Des-fluoro-anacetrapib treatment reduced the intimal area of the stented arteries by 43±5.6% (P<0.001), the media area was unchanged, and the arterial lumen area increased by 12±2.4% (P<0.05). Des-fluoro-anacetrapib treatment inhibited vascular smooth muscle cell proliferation by 41±4.5% (P<0.001). Incubation of isolated HDLs from des-fluoro-anacetrapib-treated animals with human aortic smooth muscle cells at apolipoprotein A-I concentrations comparable to their plasma levels inhibited cell proliferation and migration. These effects were dependent on scavenger receptor-B1, the adaptor protein PDZ domain-containing protein 1, and phosphatidylinositol-3-kinase/Akt activation. HDLs from des-fluoro-anacetrapib-treated animals also inhibited proinflammatory cytokine-induced human aortic smooth muscle cell proliferation and stent-induced vascular inflammation. CONCLUSIONS: Inhibiting cholesteryl ester transfer protein activity in New Zealand White rabbits with iliac artery balloon injury and stent deployment increases HDL levels, inhibits vascular smooth muscle cell proliferation, and reduces neointimal hyperplasia in an scavenger receptor-B1, PDZ domain-containing protein 1- and phosphatidylinositol-3-kinase/Akt-dependent manner.

Effects of dietary fat subtypes on glucose homeostasis during pregnancy in rats.

BACKGROUND: Dietary n-3 and n-6 polyunsaturated fatty acids (PUFAs) have an impact on insulin secretion and sensitivity but whether and how these may be related to maternal glucose homeostasis during pregnancy is unclear. METHODS: Female Wistar rats (240-250 g) were assigned to laboratory CHOW or high fat diets rich in either n-6 (safflower oil; n-6 group) or n-6 + n-3 (safflower oil + fish oil; n-3 group) PUFAs. After 10 days half of the animals in each diet group were inseminated and confirmed pregnant. An overnight fasted intravenous glucose tolerance test (500 mg glucose/kg body weight) was performed on chronically cannulated non-pregnant and 20-day pregnant rats. Indices of insulin secretion (ß) and insulin sensitivity (S) were calculated from the plasma glucose and insulin responses. The fatty acid composition of phospholipids was determined in samples of liver and two skeletal muscles (soleus and red quadriceps). RESULTS: Pregnancy in the CHOW group significantly increased ß (P < 0.001) and decreased S (P < 0.01). In contrast, both n-6 and n-3 diets abolished both the pregnancy-induced decrease in S and pregnancy-induced increase in ß with the n-3 diet having a more potent effect on both S and ß. S was positively correlated with the sum of n-3 fatty acids, with docosahexaenoic acid (22:6 n-3) the major contributor, in liver (r = 0.485; P < 0.001), red quadriceps (r = 0.421; P = 0.004) and soleus (r = 0.476; P < 0.001). In contrast S was inversely related to arachidonic acid (20:4n-6) levels in liver and red quadriceps across all groups and these relationships were particularly powerful in pregnancy (liver: r = -0.785; red quadriceps: r = -0.754, both P < 0.0001). CONCLUSIONS: The results demonstrate potent effects of dietary fat amount and profile on glucoregulation during pregnancy and emphasize the importance of the balance between dietary n-3 and n-6 PUFAs.

Increasing HDL levels by inhibiting cholesteryl ester transfer protein activity in rabbits with hindlimb ischemia is associated with increased angiogenesis.

BACKGROUND: High density lipoprotein (HDL) infusions increase new blood vessel formation (angiogenesis) in rodents with ischemic injury. This study asks if increasing HDL levels by inhibiting cholesteryl ester transfer protein (CETP) activity increases angiogenesis in New Zealand White (NZW) rabbits with hindlimb ischemia. METHODS AND RESULTS: NZW rabbits were maintained for 6weeks on chow or chow supplemented with 0.07% or 0.14% (wt/wt) of the CETP inhibitor, des-fluoro-anacetrapib. The left femoral artery was ligated after 2weeks of des-fluoro-anacetrapib treatment. The animals were sacrificed 4weeks after femoral artery ligation. Treatment with 0.07% and 0.14% (wt/wt) des-fluoro-anacetrapib reduced CETP activity by 63±12% and 81±8.6%, increased plasma apoA-I levels by 1.3±0.1- and 1.4±0.1-fold, and increased plasma HDL-cholesterol levels by 1.4±0.1- and 1.7±0.2-fold, respectively. Treatment with 0.07% and 0.14% (wt/wt) des-fluoro-anacetrapib increased the number of collateral arteries by 60±16% and 84±27%, and arteriole wall area in the ischemic hindlimbs by 84±16% and 94±13%, respectively. Capillary density in the ischemic hindlimb adductor muscle increased from 1.1±0.2 (control) to 2.1±0.3 and 2.2±0.4 in the 0.07% and 0.14% (wt/wt) des-fluoro-anacetrapib-treated animals, respectively. Incubation of HDLs from des-fluoro-anacetrapib-treated animals with human coronary artery endothelial cells at apoA-I concentrations comparable with their plasma levels increased tubule network formation. These effects were abolished by knockdown of scavenger receptor-B1 (SR-B1) and PDZK1, and pharmacological inhibition of PI3K/Akt. CONCLUSION: Increasing HDL levels by inhibiting CETP activity is associated with increased collateral blood vessel formation in NZW rabbits with hindlimb ischemia in an SR-B1- and PI3K/Akt-dependent manner.

Cholesteryl ester transfer protein inhibition enhances endothelial repair and improves endothelial function in the rabbit.

OBJECTIVE: High-density lipoproteins (HDLs) can potentially protect against atherosclerosis by multiple mechanisms, including enhancement of endothelial repair and improvement of endothelial function. This study asks if increasing HDL levels by inhibiting cholesteryl ester transfer protein activity with the anacetrapib analog, des-fluoro-anacetrapib, enhances endothelial repair and improves endothelial function in New Zealand White rabbits with balloon injury of the abdominal aorta. APPROACH AND RESULTS: New Zealand White rabbits received chow or chow supplemented with 0.07% or 0.14% (wt/wt) des-fluoro-anacetrapib for 8 weeks. Endothelial denudation of the abdominal aorta was carried out after 2 weeks. The animals were euthanized 6 weeks postinjury. Treatment with 0.07% and 0.14% des-fluoro-anacetrapib reduced cholesteryl ester transfer protein activity by 81±4.9% and 92±12%, increased plasma apolipoprotein A-I levels by 1.4±0.1-fold and 1.5±0.1-fold, increased plasma HDL-cholesterol levels by 1.8±0.2-fold and 1.9±0.1-fold, reduced intimal hyperplasia by 37±11% and 51±10%, and inhibited vascular cell proliferation by 25±6.1% and 35±6.7%, respectively. Re-endothelialization of the injured aorta increased from 43±6.7% (control) to 69±6.6% and 76±7.7% in the 0.07% and 0.14% des-fluoro-anacetrapib-treated animals, respectively. Aortic ring relaxation and guanosine 3',5'-cyclic monophosphate production in response to acetylcholine were also improved. Incubation of HDLs from the des-fluoro-anacetrapib-treated animals with human coronary artery endothelial cells increased cell proliferation and migration relative to control. These effects were abolished by knockdown of scavenger receptor-B1 and PDZ domain-containing protein 1 and by pharmacological inhibition of phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt. CONCLUSIONS: Increasing HDL levels by inhibiting cholesteryl ester transfer protein reduces intimal thickening and regenerates functional endothelium in damaged New Zealand White rabbit aortas in an scavenger receptor-B1-dependent and phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt-dependent manner.

The relationship between total bilirubin levels and total mortality in older adults: the United States National Health and Nutrition Examination Survey (NHANES) 1999-2004.

OBJECTIVE: Due to its anti-oxidant and anti-inflammatory properties, bilirubin has been associated with reduced cardiovascular risk. A recent study demonstrated an L-shaped association of pre-treatment total bilirubin levels with total mortality in a statin-treated cohort. We therefore investigated the association of total bilirubin levels with total mortality in a nationally representative sample of older adults from the general population. METHODS: A total of 4,303 participants aged ≥ 60 years from the United States National Health and Nutrition Examination Survey 1999-2004 with mortality data followed up through December 31, 2006 were included in this analysis, with a mean follow-up period of 4.5 years. RESULTS: Participants with total bilirubin levels of 0.1-0.4 mg/dl had the highest mortality rate (19.8%). Compared with participants with total bilirubin levels of 0.5-0.7 mg/dl and in a multivariable regression model, a lower total bilirubin level of 0.1-0.4 mg/dl was associated with higher risk of total mortality (hazard ratios, 1.36; 95% confidence interval, 1.07-1.72; P = 0.012), while higher levels (≥ 0.8 mg/dl) also tended to be associated with higher risk of total mortality, but this did not reach statistical significance (hazard ratios, 1.24; 95% confidence interval, 0.98-1.56; P = 0.072). CONCLUSION: In this nationally representative sample of older adults, the association of total bilirubin levels with total mortality was the highest among those with a level between 0.1 and 0.4 mg/dl. Further studies are needed to investigate whether higher total bilirubin levels could be associated with a higher mortality risk, compared to a level of 0.5-0.7 mg/dl.

Inhibition of arthritis in the Lewis rat by apolipoprotein A-I and reconstituted high-density lipoproteins.

OBJECTIVE: This study questions whether high-density lipoproteins (HDLs) and apolipoprotein A-I inhibit joint inflammation in streptococcal cell wall peptidoglycan-polysaccharide (PG-PS)-induced arthritis in female Lewis rats. APPROACH AND RESULTS: Administration of PG-PS to female Lewis rats caused acute joint inflammation after 4 days, followed by remission by day 8. The animals subsequently developed chronic joint inflammation that persisted until euthanasia at day 21. Treatment with apolipoprotein A-I 24 hours before and 24 hours after PG-PS administration reduced the acute and chronic joint inflammation. Treatment with apolipoprotein A-I at days 7, 9, and 11 after PG-PS administration reduced the chronic joint inflammation. Treatment with apolipoprotein A-I or reconstituted HDLs consisting of apolipoprotein A-I complexed with phosphatidylcholine 24 hours before and at days 1, 7, 9, and 11 after PG-PS administration reduced acute and chronic joint inflammation. Treatment with apolipoprotein A-I also reduced the inflammatory white blood cell count, synovial fluid proinflammatory cytokine levels, synovial tissue macrophage accumulation, as well as toll-like receptor 2, and inflammatory cytokine expression. At the molecular level, preincubation of human monocyte-derived macrophages with apolipoprotein A-I or reconstituted HDLs before PG-PS stimulation inhibited the PG-PS-induced increase in toll-like receptor 2 and myeloid differentiation primary response gene (88) mRNA levels, nuclear factor-κB activation, and proinflammatory cytokine production. The effects of apolipoprotein A-I and reconstituted HDLs were abolished by transfecting the human monocyte-derived macrophages with ATP-binding cassette transporter A1 or G1 siRNA. CONCLUSIONS: Apolipoprotein A-I and reconstituted HDLs attenuate PG-PS-induced arthritis in the rat. Studies in human monocyte-derived macrophages indicate that this benefit may be because of the inhibition of toll-like receptor 2 expression and decreased nuclear factor-κB activation in macrophages.

Trends in C-reactive protein levels in US adults from 1999 to 2010.

C-reactive protein (CRP) is a well-known biomarker of systemic inflammation and cardiovascular disease. We investigated the trends in prevalence of elevated CRP levels (>3.0 mg/L) in a general population of US adults. Data from 27,214 subjects aged ≥20 years in the 1999-2010 National Health and Nutrition Examination Survey were analyzed. After adjustment for age, sex, race/ethnicity, body mass index (weight (kg)/height (m)(2)), and medications for lowering blood pressure, glucose, and lipids, the prevalence of elevated CRP decreased significantly from 36.7% in 1999-2002 to 32.0% in 2007-2010, corresponding to a decrease in mean CRP level from 1.92 to 1.66 mg/L (both P < 0.001). The trend remained significant after additional adjustment for several traditional cardiovascular risk factors and use of different medications, including statins. However, the decreasing trends were attenuated after additional adjustment for total bilirubin (P = 0.08 and 0.02), which increased from 0.62 to 0.73 mg/dL over 12 years (P < 0.001). The decreasing trend of CRP levels is encouraging and may be related to the increase in total bilirubin levels. Such trends may be explained in part by the increasing use of medications such as statins, which can increase bilirubin levels and decrease CRP levels.

High-density lipoproteins inhibit vascular endothelial inflammation by increasing 3ß-hydroxysteroid-Δ24 reductase expression and inducing heme oxygenase-1.

RATIONALE: Lipid-free apolipoprotein (apo) A-I and discoidal reconstituted high-density lipoproteins (rHDL) containing apoA-I, (A-I)rHDL, inhibit vascular inflammation by increasing 3ß-hydroxysteroid-Δ24 reductase (DHCR24) expression. OBJECTIVE: To determine whether the lipid-free apoA-I-mediated and (A-I)rHDL-mediated increase in DHCR24 expression induces the cytoprotective and potentially cardioprotective enzyme, heme oxygenase-1 (HO-1). METHODS AND RESULTS: In vivo: A single intravenous infusion of lipid-free apoA-I (8 mg/kg) administered 24 hours before inserting a nonocclusive periarterial carotid collar into New Zealand White rabbits decreased collar-induced endothelial vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 expression, reduced intima/media neutrophil infiltration, and increased DHCR24 and HO-1 mRNA levels. Knockdown of vascular DHCR24 and HO-1 and systemic administration of tin-protoporphyrin-IX, an HO inhibitor, abolished these anti-inflammatory effects. In vitro: Preincubation of human coronary artery endothelial cells with (A-I)rHDL before activation with tumor necrosis factor-α increased DHCR24 and HO-1 mRNA levels and inhibited cytokine-induced vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 expression. Transfection of the cells with DHCR24 and HO-1 small interfering RNA and tin-protoporphyrin-IX treatment abolished these effects. The (A-I)rHDL-mediated induction of HO-1 was reduced in human coronary artery endothelial cells transfected with DHCR24 small interfering RNA. Transfection of human coronary artery endothelial cells with HO-1 small interfering RNA and tin-protoporphyrin-IX treatment did not inhibit the (A-I)rHDL-mediated increase in DHCR24 expression. Inhibition of phosphatidylinositol 3-kinase/Akt reduced the (A-I)rHDL-mediated increase in HO-1, but not DHCR24 expression. The activation of phosphatidylinositol 3-kinase/Akt by (A-I)rHDL was decreased in human coronary artery endothelial cells that were transfected with DHCR24 small interfering RNA. CONCLUSIONS: Lipid-free apoA-I and (A-I)rHDL inhibit inflammation by increasing DHCR24 expression, which, in turn, activates phosphatidylinositol 3-kinase/Akt and induces HO-1.