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Annema W, Willemsen HM, de Boer JF, Dikkers A, van der Giet M, Nieuwland W, Muller Kobold AC, van Pelt LJ, Slart RHJA, van der Horst ICC, Dullaart RPF, Tio RA, Tietge UJF. HDL function is impaired in acute myocardial infarction independent of plasma HDL cholesterol levels. J Clin Lipidol 2016; 10:1318-1328. [PMID: 27919348 DOI: 10.1016/j.jacl.2016.08.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/15/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND High-density lipoproteins (HDLs) protect against the development of atherosclerotic cardiovascular disease. HDL function represents an emerging concept in cardiovascular research. OBJECTIVE This study investigated the association between HDL functionality and acute myocardial infarction (MI) independent of HDL-cholesterol plasma levels. METHODS Participants (non-ST-segment elevation MI, non-STEMI, n = 41; STEMI, n = 37; non-MI patients, n = 33) from a prospective follow-up study enrolling patients with acute chest pain were matched for age and plasma HDL cholesterol. The in vitro capacity of HDL to (1) mediate cholesterol efflux from macrophage foam cells, (2) prevent low-density lipoprotein oxidation, and (3) inhibit TNF-α-induced vascular adhesion molecule-1 expression in endothelial cells was determined. RESULTS STEMI-HDL displayed reduced cholesterol efflux (P < .001) and anti-inflammatory functionality (P = .001), whereas the antioxidative properties were unaltered. Cholesterol efflux correlated with the anti-inflammatory HDL activity (P < .001). Not C-reactive protein levels, a marker of systemic inflammation, but specifically plasma myeloperoxidase levels were independently associated with impaired HDL function (efflux: P = .022; anti-inflammation: P < .001). Subjects in the higher risk quartile of efflux (odds ratio [OR], 5.66; 95% confidence interval [CI], 1.26-25.00; P = .024) as well as anti-inflammatory functionality of HDL (OR, 5.53; 95% CI, 1.83-16.73; P = .002) had a higher OR for MI vs those in the three lower risk quartiles combined. CONCLUSION Independent of plasma HDL cholesterol levels, 2 of 3 antiatherogenic HDL functionalities tested were significantly impaired in STEMI patients, namely cholesterol efflux and anti-inflammatory properties. Increased myeloperoxidase levels might represent a major contributing mechanism for decreased HDL functionality in MI patients.
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Bakker LEH, Boon MR, Annema W, Dikkers A, van Eyk HJ, Verhoeven A, Mayboroda OA, Jukema JW, Havekes LM, Meinders AE, Willems van Dijk K, Jazet IM, Tietge UJF, Rensen PCN. HDL functionality in South Asians as compared to white Caucasians. Nutr Metab Cardiovasc Dis 2016; 26:697-705. [PMID: 27052926 DOI: 10.1016/j.numecd.2016.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 01/31/2016] [Accepted: 02/10/2016] [Indexed: 12/28/2022]
Abstract
BACKGROUND AND AIMS South Asians have an exceptionally high risk of developing cardiovascular disease compared to white Caucasians. A contributing factor might be dysfunction of high density lipoprotein (HDL). We aimed to compare HDL function in different age groups of both ethnicities. METHODS AND RESULTS HDL functionality with respect to cholesterol efflux, anti-oxidation and anti-inflammation was determined using fasting, apoB-depleted, plasma samples from South Asian and white Caucasian neonates (n = 14 each), adolescent healthy men (n = 12 each, 18-25 y), and adult overweight men (n = 12 each, 40-50 y). Adolescents were subjected to a 5-day high fat high calorie diet (HCD) and adults to an 8-day very low calorie diet (LCD). Additionally, HDL composition was measured in adolescents and adults using (1)H-NMR spectroscopy. Anti-oxidative capacity was lower in South Asian adults before LCD (19.4 ± 2.1 vs. 25.8 ± 1.2%, p = 0.045, 95%-CI = [0.1; 12.7]) and after LCD (16.4 ± 2.4 vs. 27.6 ± 2.7%, p = 0.001, 95%-CI = [4.9; 17.5]). Anti-inflammatory capacity was reduced in South Asian neonates (23.8 ± 1.2 vs. 34.9 ± 1.3%, p = 0.000001, 95%-CI = [-14.6; -7.5]), and was negatively affected by an 8-day LCD only in South Asian adults (-12.2 ± 4.3%, p = 0.005, 95%-CI = [-5.9; -1.2]). Cholesterol efflux capacity was increased in response to HCD in adolescents (South Asians: +6.3 ± 2.9%, p = 0.073, 95%-CI = [-0.02; 0.46], Caucasians: +11.8 ± 3.4%, p = 0.002, 95%-CI = [0.17;0.65]) and decreased after LCD in adults (South Asians: -10.3 ± 2.4%, p < 0.001, 95%-CI = [-0.57; -0.20], Caucasians: -13.7 ± 1.9%, p < 0.00001, 95%-CI = [-0.67; -0.33]). Although subclass analyses of HDL showed no differences between ethnicities, cholesterol efflux correlated best with cholesterol and phospholipid within small HDL compared to other HDL subclasses and constituents. CONCLUSION Impaired HDL functionality in South Asians may be a contributing factor to their high CVD risk. CLINICAL TRIAL REGISTRATION NTR 2473 (URL: http://www.trialregister.nl/).
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Schonewille M, de Boer JF, Mele L, Wolters H, Bloks VW, Wolters JC, Kuivenhoven JA, Tietge UJF, Brufau G, Groen AK. Statins increase hepatic cholesterol synthesis and stimulate fecal cholesterol elimination in mice. J Lipid Res 2016; 57:1455-64. [PMID: 27313057 DOI: 10.1194/jlr.m067488] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 12/19/2022] Open
Abstract
Statins are competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis. Statins reduce plasma cholesterol levels, but whether this is actually caused by inhibition of de novo cholesterol synthesis has not been clearly established. Using three different statins, we investigated the effects on cholesterol metabolism in mice in detail. Surprisingly, direct measurement of whole body cholesterol synthesis revealed that cholesterol synthesis was robustly increased in statin-treated mice. Measurement of organ-specific cholesterol synthesis demonstrated that the liver is predominantly responsible for the increase in cholesterol synthesis. Excess synthesized cholesterol did not accumulate in the plasma, as plasma cholesterol decreased. However, statin treatment led to an increase in cholesterol removal via the feces. Interestingly, enhanced cholesterol excretion in response to rosuvastatin and lovastatin treatment was mainly mediated via biliary cholesterol secretion, whereas atorvastatin mainly stimulated cholesterol removal via the transintestinal cholesterol excretion pathway. Moreover, we show that plasma cholesterol precursor levels do not reflect cholesterol synthesis rates during statin treatment in mice. In conclusion, cholesterol synthesis is paradoxically increased upon statin treatment in mice. However, statins potently stimulate the excretion of cholesterol from the body, which sheds new light on possible mechanisms underlying the cholesterol-lowering effects of statins.
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Leberkühne LJ, Ebtehaj S, Dimova LG, Dikkers A, Dullaart RPF, Bakker SJL, Tietge UJF. The predictive value of the antioxidative function of HDL for cardiovascular disease and graft failure in renal transplant recipients. Atherosclerosis 2016; 249:181-5. [PMID: 27107804 DOI: 10.1016/j.atherosclerosis.2016.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Protection of low-density lipoproteins (LDL) against oxidative modification is a key anti-atherosclerotic property of high-density lipoproteins (HDL). This study evaluated the predictive value of the HDL antioxidative function for cardiovascular mortality, all-cause mortality and chronic graft failure in renal transplant recipients (RTR). METHODS The capacity of HDL to inhibit native LDL oxidation was determined in vitro in a prospective cohort of renal transplant recipients (RTR, n = 495, median follow-up 7.0 years). RESULTS The HDL antioxidative functionality was significantly higher in patients experiencing graft failure (57.4 ± 9.7%) than in those without (54.2 ± 11.3%; P = 0.039), while there were no differences for cardiovascular and all-cause mortality. Specifically glomerular filtration rate (P = 0.001) and C-reactive protein levels (P = 0.006) associated independently with antioxidative functionality in multivariate linear regression analyses. Cox regression analysis demonstrated a significant relationship between antioxidative functionality of HDL and graft failure in age-adjusted analyses, but significance was lost following adjustment for baseline kidney function and inflammatory load. No significant association was found between HDL antioxidative functionality and cardiovascular and all-cause mortality. CONCLUSION This study demonstrates that the antioxidative function of HDL (i) does not predict cardiovascular or all-cause mortality in RTR, but (ii) conceivably contributes to the development of graft failure, however, not independent of baseline kidney function and inflammatory load.
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Apro J, Tietge UJF, Dikkers A, Parini P, Angelin B, Rudling M. Impaired Cholesterol Efflux Capacity of High-Density Lipoprotein Isolated From Interstitial Fluid in Type 2 Diabetes Mellitus-Brief Report. Arterioscler Thromb Vasc Biol 2016; 36:787-91. [PMID: 27034474 PMCID: PMC4845764 DOI: 10.1161/atvbaha.116.307385] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/23/2016] [Indexed: 12/19/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— Patients with type 2 diabetes mellitus (T2D) have an increased risk of cardiovascular disease, the mechanism of which is incompletely understood. Their high-density lipoprotein (HDL) particles in plasma have been reported to have impaired cholesterol efflux capacity. However, the efflux capacity of HDL from interstitial fluid (IF), the starting point for reverse cholesterol transport, has not been studied. We here investigated the cholesterol efflux capacity of HDL from IF and plasma from T2D patients and healthy controls. Approach and Results— HDL was isolated from IF and peripheral plasma from 35 T2D patients and 35 age- and sex-matched healthy controls. Cholesterol efflux to HDL was determined in vitro, normalized for HDL cholesterol, using cholesterol-loaded macrophages. Efflux capacity of plasma HDL was 10% lower in T2D patients than in healthy controls, in line with previous observations. This difference was much more pronounced for HDL from IF, where efflux capacity was reduced by 28% in T2D. Somewhat surprisingly, the efflux capacity of HDL from IF was lower than that of plasma HDL, by 15% and 32% in controls and T2D patients, respectively. Conclusion— These data demonstrate that (1) HDL from IF has a lower cholesterol efflux capacity than plasma HDL and (2) the efflux capacity of HDL from IF is severely impaired in T2D when compared with controls. Because IF comprises the compartment where reverse cholesterol transport is initiated, the marked reduction in cholesterol efflux capacity of IF-HDL from T2D patients may play an important role for their increased risk to develop atherosclerosis.
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van der Heijden RA, Bijzet J, Meijers WC, Yakala GK, Kleemann R, Nguyen TQ, de Boer RA, Schalkwijk CG, Hazenberg BPC, Tietge UJF, Heeringa P. Obesity-induced chronic inflammation in high fat diet challenged C57BL/6J mice is associated with acceleration of age-dependent renal amyloidosis. Sci Rep 2015; 5:16474. [PMID: 26563579 PMCID: PMC4643235 DOI: 10.1038/srep16474] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/13/2015] [Indexed: 01/13/2023] Open
Abstract
Obesity-induced inflammation presumably accelerates the development of chronic kidney diseases. However, little is known about the sequence of these inflammatory events and their contribution to renal pathology. We investigated the effects of obesity on the evolution of age-dependent renal complications in mice in conjunction with the development of renal and systemic low-grade inflammation (LGI). C57BL/6J mice susceptible to develop age-dependent sclerotic pathologies with amyloid features in the kidney, were fed low (10% lard) or high-fat diets (45% lard) for 24, 40 and 52 weeks. HFD-feeding induced overt adiposity, altered lipid and insulin homeostasis, increased systemic LGI and adipokine release. HFD-feeding also caused renal upregulation of pro-inflammatory genes, infiltrating macrophages, collagen I protein, increased urinary albumin and NGAL levels. HFD-feeding severely aggravated age-dependent structural changes in the kidney. Remarkably, enhanced amyloid deposition rather than sclerosis was observed. The degree of amyloidosis correlated significantly with body weight. Amyloid deposits stained positive for serum amyloid A (SAA) whose plasma levels were chronically elevated in HFD mice. Our data indicate obesity-induced chronic inflammation as a risk factor for the acceleration of age-dependent renal amyloidosis and functional impairment in mice, and suggest that obesity-enhanced chronic secretion of SAA may be the driving factor behind this process.
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Dikkers A, de Boer JF, Groen AK, Tietge UJF. Hepatic ABCG5/G8 overexpression substantially increases biliary cholesterol secretion but does not impact in vivo macrophage-to-feces RCT. Atherosclerosis 2015; 243:402-6. [PMID: 26520893 DOI: 10.1016/j.atherosclerosis.2015.10.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/30/2015] [Accepted: 10/05/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND AIMS Biliary cholesterol secretion is important for reverse cholesterol transport (RCT). ABCG5/G8 contribute most cholesterol mass secretion into bile. We investigated the impact of hepatic ABCG5/G8 on cholesterol metabolism and RCT. METHODS Biliary and fecal sterol excretion (FSE) as well as RCT were determined using wild-type controls, Abcg8 knockout mice, Abcg8 knockouts with adenovirus-mediated hepatocyte-specific Abcg8 reinstitution and hepatic Abcg5/g8 overexpression in wild-types. RESULTS In Abcg8 knockouts, biliary cholesterol secretion was decreased by 75% (p < 0.001), while mass FSE and RCT were unchanged. Hepatic reinstitution of Abcg8 increased biliary cholesterol secretion 5-fold (p < 0.001) without changing FSE or overall RCT. Overexpression of both ABCG5/G8 elevated biliary cholesterol secretion 5-fold and doubled FSE (p < 0.001) without affecting overall RCT. CONCLUSIONS ABCG5/G8 mediate mass biliary cholesterol secretion but not from a RCT-relevant pool. Intervention strategies aiming at increasing hepatic Abcg5/g8 expression for enhancing RCT are not likely to be successful.
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Annema W, Dikkers A, de Boer JF, Dullaart RPF, Sanders JSF, Bakker SJL, Tietge UJF. HDL Cholesterol Efflux Predicts Graft Failure in Renal Transplant Recipients. J Am Soc Nephrol 2015; 27:595-603. [PMID: 26319244 DOI: 10.1681/asn.2014090857] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 03/31/2015] [Indexed: 01/14/2023] Open
Abstract
High-density lipoprotein (HDL) particles are involved in the protection against cardiovascular disease by promoting cholesterol efflux, in which accumulated cholesterol is removed from macrophage foam cells. We investigated whether HDL cholesterol efflux capacity is associated with cardiovascular mortality, all-cause mortality, and graft failure in a cohort of renal transplant recipients (n=495, median follow-up 7.0 years). Cholesterol efflux capacity at baseline was quantified using incubation of human macrophage foam cells with apolipoprotein B-depleted plasma. Baseline efflux capacity was not different in deceased patients and survivors (P=0.60 or P=0.50 for cardiovascular or all-cause mortality, respectively), whereas recipients developing graft failure had lower efflux capacity than those with functioning grafts (P<0.001). Kaplan-Meier analysis demonstrated a lower risk for graft failure (P=0.004) but not cardiovascular (P=0.30) or all-cause mortality (P=0.31) with increasing gender-stratified tertiles of efflux capacity. Cox regression analyses adjusted for age and gender showed that efflux capacity was not associated with cardiovascular mortality (hazard ratio [HR], 0.89; 95% confidence interval [95% CI], 0.67 to 1.19; P=0.43). Furthermore, the association between efflux capacity and all-cause mortality (HR, .79; 95% CI, 0.63 to 0.98; P=0.031) disappeared after further adjustment for potential confounders. However, efflux capacity at baseline significantly predicted graft failure (HR, 0.43; 95% CI, 0.29 to 0.64; P<0.001) independent of apolipoprotein A-I, HDL cholesterol, or creatinine clearance. In conclusion, this prospective study shows that cholesterol efflux capacity from macrophage foam cells is not associated with cardiovascular or all-cause mortality but is a strong predictor of graft failure independent of plasma HDL cholesterol levels in renal transplant recipients.
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Janssen H, Wagner CS, Demmer P, Callies S, Sölter G, Loghmani-khouzani H, Hu N, Schuett H, Tietge UJF, Warnecke G, Larmann J, Theilmeier G. Acute perioperative-stress-induced increase of atherosclerotic plaque volume and vulnerability to rupture in apolipoprotein-E-deficient mice is amenable to statin treatment and IL-6 inhibition. Dis Model Mech 2015; 8:1071-80. [PMID: 26092124 PMCID: PMC4582096 DOI: 10.1242/dmm.018713] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 06/09/2015] [Indexed: 01/15/2023] Open
Abstract
Myocardial infarction and stroke are frequent after surgical procedures and consume a considerable amount of benefit of surgical therapy. Perioperative stress, induced by surgery, is composed of hemodynamic and inflammatory reactions. The effects of perioperative stress on atherosclerotic plaques are ill-defined. Murine models to investigate the influence of perioperative stress on plaque stability and rupture are not available. We developed a model to investigate the influence of perioperative stress on plaque growth and stability by exposing apolipoprotein-E-deficient mice, fed a high cholesterol diet for 7 weeks, to a double hit consisting of 30 min of laparotomy combined with a substantial blood loss (approximately 20% of total blood volume; 400 µl). The innominate artery was harvested 72 h after the intervention. Control groups were sham and baseline controls. Interleukin-6 (IL-6) and serum amyloid A (SAA) plasma levels were determined. Plaque load, vascular smooth muscle cell (VSMC) and macrophage content were quantified. Plaque stability was assessed using the Stary score and frequency of signs of plaque rupture were assessed. High-dose atorvastatin (80 mg/kg body weight/day) was administered for 6 days starting 3 days prior to the double hit. A single dose of an IL-6-neutralizing antibody or the fusion protein gp130-Fc selectively targeting IL-6 trans-signaling was subcutaneously injected. IL-6 plasma levels increased, peaking at 6 h after the intervention. SAA levels peaked at 24 h (n=4, P<0.01). Plaque volume increased significantly with the double hit compared to sham (n=8, P<0.01). More plaques were scored as complex or bearing signs of rupture after the double hit compared to sham (n=5-8, P<0.05). Relative VSMC and macrophage content remained unchanged. IL-6-inhibition or atorvastatin, but not blocking of IL-6 trans-signaling, significantly decreased plaque volume and complexity (n=8, P<0.01). Using this model, researchers will be able to further investigate the pathophysiology of perioperative plaque stability, which can result in myocardial infarction, and, additionally, to test potential protective strategies. Summary: We developed a model to study the dynamics of atherosclerotic plaque growth and stability following surgery, and show that IL-6 inhibition and statins beneficially affect plaque volume and complexity.
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Favari E, Chroni A, Tietge UJF, Zanotti I, Escolà-Gil JC, Bernini F. Cholesterol efflux and reverse cholesterol transport. Handb Exp Pharmacol 2015; 224:181-206. [PMID: 25522988 DOI: 10.1007/978-3-319-09665-0_4] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Both alterations of lipid/lipoprotein metabolism and inflammatory events contribute to the formation of the atherosclerotic plaque, characterized by the accumulation of abnormal amounts of cholesterol and macrophages in the artery wall. Reverse cholesterol transport (RCT) may counteract the pathogenic events leading to the formation and development of atheroma, by promoting the high-density lipoprotein (HDL)-mediated removal of cholesterol from the artery wall. Recent in vivo studies established the inverse relationship between RCT efficiency and atherosclerotic cardiovascular diseases (CVD), thus suggesting that the promotion of this process may represent a novel strategy to reduce atherosclerotic plaque burden and subsequent cardiovascular events. HDL plays a primary role in all stages of RCT: (1) cholesterol efflux, where these lipoproteins remove excess cholesterol from cells; (2) lipoprotein remodeling, where HDL undergo structural modifications with possible impact on their function; and (3) hepatic lipid uptake, where HDL releases cholesterol to the liver, for the final excretion into bile and feces. Although the inverse association between HDL plasma levels and CVD risk has been postulated for years, recently this concept has been challenged by studies reporting that HDL antiatherogenic functions may be independent of their plasma levels. Therefore, assessment of HDL function, evaluated as the capacity to promote cell cholesterol efflux may offer a better prediction of CVD than HDL levels alone. Consistent with this idea, it has been recently demonstrated that the evaluation of serum cholesterol efflux capacity (CEC) is a predictor of atherosclerosis extent in humans.
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Tietge UJF. HDL - Hope Dies Last? Curr Opin Lipidol 2015; 26:150-1. [PMID: 25756811 DOI: 10.1097/mol.0000000000000164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lichtenstein L, Serhan N, Espinosa-Delgado S, Fabre A, Annema W, Tietge UJF, Robaye B, Boeynaems JM, Laffargue M, Perret B, Martinez LO. Increased atherosclerosis in P2Y13/apolipoprotein E double-knockout mice: contribution of P2Y13 to reverse cholesterol transport. Cardiovasc Res 2015; 106:314-23. [PMID: 25770145 DOI: 10.1093/cvr/cvv109] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/07/2015] [Indexed: 11/14/2022] Open
Abstract
AIMS High-density lipoproteins (HDLs) protect against atherosclerosis mainly due to their function in hepatobiliary reverse cholesterol transport (RCT). This is a process whereby excess cholesterol from peripheral tissues is transported by HDL particles to the liver for further metabolism and biliary excretion. Hepatic uptake of HDL holoparticles involves the P2Y13 receptor, independently of the selective cholesteryl ester uptake mediated by scavenger receptor class B, type I (SR-BI). Accordingly, P2Y13-deficient mice (P2Y13 (-/-)) have impaired RCT. This study assessed whether P2Y13 deficiency would affect atherosclerotic development. METHODS AND RESULTS P2Y13 (-/-) mice were crossbred with atherosclerosis-prone apoE(-/-) mice. When 15 weeks old, P2Y13 (-/-)/apoE(-/-) mice had more aortic sinus lesions than apoE(-/-) mice. Bone marrow transplantation showed that the absence of the P2Y13 receptor in blood cells did not lead to significantly greater atherosclerotic plaque size formation compared with control apoE(-/-) reconstituted animals. Conversely, the absence of the P2Y13 receptor, except in blood cells, resulted in lesion sizes similar to that in P2Y13 (-/-)/apoE(-/-) reconstituted mice, pointing to a role for non-haematopoietic-derived P2Y13. Unexpectedly, P2Y13 (-/-)/apoE(-/-) mice displayed a lower HDL-cholesterol level than apoE(-/-) mice, which might be due to greater SR-BI expression in the liver. However, P2Y13 deficiency in apoE(-/-) mice was translated into reduced biliary and faecal sterol excretion and impaired RCT from macrophage to faeces, suggesting that an alteration in hepatobiliary RCT could be solely responsible for the greater atherosclerosis observed. CONCLUSION The P2Y13 receptor protects against atherosclerosis, primarily through its role in hepatobiliary RCT.
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Nagy RA, van Montfoort APA, Dikkers A, van Echten-Arends J, Homminga I, Land JA, Hoek A, Tietge UJF. Presence of bile acids in human follicular fluid and their relation with embryo development in modified natural cycle IVF. Hum Reprod 2015; 30:1102-9. [PMID: 25753582 DOI: 10.1093/humrep/dev034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/03/2015] [Indexed: 12/20/2022] Open
Abstract
STUDY QUESTION Are bile acids (BA) and their respective subspecies present in human follicular fluid (FF) and do they relate to embryo quality in modified natural cycle IVF (MNC-IVF)? SUMMARY ANSWER BA concentrations are 2-fold higher in follicular fluid than in serum and ursodeoxycholic acid (UDCA) derivatives were associated with development of top quality embryos on Day 3 after fertilization. WHAT IS KNOWN ALREADY Granulosa cells are capable of synthesizing BA, but a potential correlation with oocyte and embryo quality as well as information on the presence and role of BA subspecies in follicular fluid have yet to be investigated. STUDY DESIGN, SIZE, DURATION Between January 2001 and June 2004, follicular fluid and serum samples were collected from 303 patients treated in a single academic centre that was involved in a multicentre cohort study on the effectiveness of MNC-IVF. PARTICIPANTS/MATERIALS, SETTING, METHODS Material from patients who underwent a first cycle of MNC-IVF was used. Serum was not stored from all patients, and the available material comprised 156 follicular fluid and 116 matching serum samples. Total BA and BA subspecies were measured in follicular fluid and in matching serum by enzymatic fluorimetric assay and liquid chromatography-mass spectrometry, respectively. The association of BA in follicular fluid with oocyte and embryo quality parameters, such as fertilization rate and cell number, presence of multinucleated blastomeres and percentage of fragmentation on Day 3, was analysed. MAIN RESULTS AND THE ROLE OF CHANCE Embryos with eight cells on Day 3 after oocyte retrieval were more likely to originate from follicles with a higher level of UDCA derivatives than those with fewer than eight cells (P < 0.05). Furthermore, follicular fluid levels of chenodeoxycholic derivatives were higher and deoxycholic derivatives were lower in the group of embryos with fragmentation compared with those without (each P < 0.05). Levels of total BA were 2-fold higher in follicular fluid compared with serum (P < 0.001), but had no predictive value for oocyte and embryo quality. LIMITATIONS, REASONS FOR CAUTION Only samples originating from first cycle MNC-IVF were used, which resulted in 14 samples only from women with an ongoing pregnancy, therefore further prospective studies are required to confirm the association of UDCA with IVF pregnancy outcomes. The inter-cycle variability of BA levels in follicular fluid within individuals has yet to be investigated. We checked for macroscopic signs of contamination of follicular fluid by blood but the possibility that small traces of blood were present within the follicular fluid remains. Finally, although BA are considered stable when stored at -20°C, there was a time lag of 10 years between the collection and analysis of follicular fluid and serum samples. WIDER IMPLICATIONS OF THE FINDINGS The favourable relation between UDCA derivatives in follicular fluid and good embryo development and quality deserves further prospective research, with live birth rates as the end-point. STUDY FUNDING/COMPETING INTERESTS This work was supported by a grant from the Netherlands Organisation for Scientific Research (VIDI Grant 917-56-358 to U.J.F.T.). No competing interests are reported.
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Hijmans BS, Tiemann CA, Grefhorst A, Boesjes M, van Dijk TH, Tietge UJF, Kuipers F, van Riel NAW, Groen AK, Oosterveer MH. A systems biology approach reveals the physiological origin of hepatic steatosis induced by liver X receptor activation. FASEB J 2014; 29:1153-64. [PMID: 25477282 DOI: 10.1096/fj.14-254656] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 11/05/2014] [Indexed: 12/12/2022]
Abstract
Liver X receptor (LXR) agonists exert potent antiatherosclerotic actions but simultaneously induce excessive triglyceride (TG) accumulation in the liver. To obtain a detailed insight into the underlying mechanism of hepatic TG accumulation, we used a novel computational modeling approach called analysis of dynamic adaptations in parameter trajectories (ADAPT). We revealed that both input and output fluxes to hepatic TG content are considerably induced on LXR activation and that in the early phase of LXR agonism, hepatic steatosis results from only a minor imbalance between the two. It is generally believed that LXR-induced hepatic steatosis results from increased de novo lipogenesis (DNL). In contrast, ADAPT predicted that the hepatic influx of free fatty acids is the major contributor to hepatic TG accumulation in the early phase of LXR activation. Qualitative validation of this prediction showed a 5-fold increase in the contribution of plasma palmitate to hepatic monounsaturated fatty acids on acute LXR activation, whereas DNL was not yet significantly increased. This study illustrates that complex effects of pharmacological intervention can be translated into distinct patterns of metabolic regulation through state-of-the-art mathematical modeling.
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Demetz E, Schroll A, Auer K, Heim C, Patsch JR, Eller P, Theurl M, Theurl I, Theurl M, Seifert M, Lener D, Stanzl U, Haschka D, Asshoff M, Dichtl S, Nairz M, Huber E, Stadlinger M, Moschen AR, Li X, Pallweber P, Scharnagl H, Stojakovic T, März W, Kleber ME, Garlaschelli K, Uboldi P, Catapano AL, Stellaard F, Rudling M, Kuba K, Imai Y, Arita M, Schuetz JD, Pramstaller PP, Tietge UJF, Trauner M, Norata GD, Claudel T, Hicks AA, Weiss G, Tancevski I. The arachidonic acid metabolome serves as a conserved regulator of cholesterol metabolism. Cell Metab 2014; 20:787-798. [PMID: 25444678 PMCID: PMC4232508 DOI: 10.1016/j.cmet.2014.09.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/10/2014] [Accepted: 09/08/2014] [Indexed: 12/12/2022]
Abstract
Cholesterol metabolism is closely interrelated with cardiovascular disease in humans. Dietary supplementation with omega-6 polyunsaturated fatty acids including arachidonic acid (AA) was shown to favorably affect plasma LDL-C and HDL-C. However, the underlying mechanisms are poorly understood. By combining data from a GWAS screening in >100,000 individuals of European ancestry, mediator lipidomics, and functional validation studies in mice, we identify the AA metabolome as an important regulator of cholesterol homeostasis. Pharmacological modulation of AA metabolism by aspirin induced hepatic generation of leukotrienes (LTs) and lipoxins (LXs), thereby increasing hepatic expression of the bile salt export pump Abcb11. Induction of Abcb11 translated in enhanced reverse cholesterol transport, one key function of HDL. Further characterization of the bioactive AA-derivatives identified LX mimetics to lower plasma LDL-C. Our results define the AA metabolomeasconserved regulator of cholesterol metabolism, and identify AA derivatives as promising therapeutics to treat cardiovascular disease in humans.
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Adepu S, Katta K, Tietge UJF, Kwakernaak AJ, Dam W, van Goor H, Dullaart RPF, Navis GJ, Bakker SJL, van den Born J. Hepatic syndecan-1 changes associate with dyslipidemia after renal transplantation. Am J Transplant 2014; 14:2328-38. [PMID: 25154787 DOI: 10.1111/ajt.12842] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/25/2014] [Accepted: 05/18/2014] [Indexed: 01/25/2023]
Abstract
Syndecan-1 is a transmembrane heparan sulfate (HS) proteoglycan present on hepatocytes and involved in uptake of triglyceride-rich lipoproteins via its HS polysaccharide side chains. We hypothesized that altered hepatic syndecan-1 metabolism could be involved in dyslipidemia related to renal transplantation. In a rat renal transplantation model elevated plasma triglycerides were associated with fivefold increased expression of hepatic syndecan-1 mRNA (p < 0.01), but not protein. Expression of syndecan-1 sheddases (ADAM17, MMP9) and heparanase was significantly up-regulated after renal transplantation (all p < 0.05). Profiling of HS side chains revealed loss of hepatic HS upon renal transplantation accompanied by significant decreased functional capacity for VLDL binding (p = 0.02). In a human renal transplantation cohort (n = 510), plasma levels of shed syndecan-1 were measured. Multivariate analysis showed plasma syndecan-1 to be independently associated with triglycerides (p < 0.0001) and inversely with HDL cholesterol (p < 0.0001). Last, we show a physical association of syndecan-1 to HDL from renal transplant recipients (RTRs), but not to HDL from healthy controls. Our data suggest that after renal transplantation loss of hepatic HS together with increased syndecan-1 shedding hampers lipoprotein binding and uptake by the liver contributing to dyslipidemia. Our data open perspectives toward improvement of lipid profiles by targeted inhibition of syndecan-1 catabolism in renal transplantation.
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de Boer JF, Dikkers A, Jurdzinski A, von Felden J, Gaestel M, Bavendiek U, Tietge UJF. Mitogen-activated protein kinase-activated protein kinase 2 deficiency reduces insulin sensitivity in high-fat diet-fed mice. PLoS One 2014; 9:e106300. [PMID: 25233471 PMCID: PMC4169416 DOI: 10.1371/journal.pone.0106300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 08/04/2014] [Indexed: 01/07/2023] Open
Abstract
Adipose tissue inflammation is considered an important contributor to insulin resistance. Mitogen-activated protein kinase-activated protein kinase 2 (MK2) is a major downstream target of p38 MAPK and enhances inflammatory processes. In line with the role of MK2 as contributor to inflammation, MK2−/− mice are protected against inflammation in different disease models. Therefore, MK2 is considered an attractive therapeutic target for the treatment of chronic inflammatory diseases. This study tested the impact of MK2-deficiency on high-fat diet (HFD)-induced adipose tissue inflammation and insulin resistance. After feeding MK2−/− and WT control mice a HFD (60% energy from fat) for 24 weeks, body weight was not different between groups. Also, liver weight and the amount of abdominal fat remained unchanged. However, in MK2−/− mice plasma cholesterol levels were significantly increased. Surprisingly, macrophage infiltration in adipose tissue was not altered. However, adipose tissue macrophages were more skewed to the inflammatory M1 phenotype in MK2−/− mice. This differerence in macrophage polarization did however not translate in significantly altered expression levels of Mcp-1, Tnfα and Il6. Glucose and insulin tolerance tests demonstrated that MK2−/− mice had a significantly reduced glucose tolerance and increased insulin resistance. Noteworthy, the expression of the insulin-responsive glucose transporter type 4 (GLUT4) in adipose tissue of MK2−/− mice was reduced by 55% (p<0.05) and 33% (p<0.05) on the mRNA and protein level, respectively, compared to WT mice. In conclusion, HFD-fed MK2−/− display decreased glucose tolerance and increased insulin resistance compared to WT controls. Decreased adipose tissue expression of GLUT4 might contribute to this phenotype. The data obtained in this study indicate that clinical use of MK2 inhibitors has to be evaluated with caution, taking potential metabolic adverse effects into account.
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Out C, Dikkers A, Laskewitz A, Boverhof R, van der Ley C, Kema IP, Wolters H, Havinga R, Verkade HJ, Kuipers F, Tietge UJF, Groen AK. Prednisolone increases enterohepatic cycling of bile acids by induction of Asbt and promotes reverse cholesterol transport. J Hepatol 2014; 61:351-7. [PMID: 24681341 DOI: 10.1016/j.jhep.2014.03.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 02/21/2014] [Accepted: 03/19/2014] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Glucocorticoids, produced by the adrenal gland under control of the hypothalamic-pituitary-adrenal axis, exert their metabolic actions largely via activation of the glucocorticoid receptor (GR). Synthetic glucocorticoids are widely used as anti-inflammatory and immunosuppressive drugs but their application is hampered by adverse metabolic effects. Recently, it has been shown that GR may regulate several genes involved in murine bile acid (BA) and cholesterol metabolism, yet the physiological relevance hereof is controversial. The aim of this study is to provide a mechanistic basis for effects of prednisolone on BA and cholesterol homeostasis in mice. METHODS Male BALB/c mice were treated with prednisolone (12.5mg/kg/day) for 7days by subcutaneous implantation of slow-release pellets, followed by extensive metabolic profiling. RESULTS Sustained prednisolone treatment induced the expression of the apical sodium-dependent bile acid transporter (Asbt) in the ileum, which stimulated BA absorption. This resulted in elevated plasma BA levels and enhanced biliary BA secretion. Concomitantly, both biliary cholesterol and phospholipid secretion rates were increased. Enhanced BA reabsorption suppressed hepatic BA synthesis, as evident from hepatic gene expression, reduced plasma C4 levels and reduced fecal BA loss. Plasma HDL cholesterol levels were elevated in prednisolone-treated mice, which likely contributed to the stimulated flux of cholesterol from intraperitoneally injected macrophage foam cells into feces. CONCLUSIONS Sustained prednisolone treatment increases enterohepatic recycling of BA, leading to elevated plasma levels and reduced synthesis in the absence of cholestasis. Under these conditions, prednisolone promotes macrophage-derived reverse cholesterol transport.
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Dullaart RPF, Tietge UJF, Kwakernaak AJ, Dikkeschei BD, Perton F, Tio RA. Alterations in plasma lecithin:cholesterol acyltransferase and myeloperoxidase in acute myocardial infarction: implications for cardiac outcome. Atherosclerosis 2014; 234:185-92. [PMID: 24661908 DOI: 10.1016/j.atherosclerosis.2014.02.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/30/2014] [Accepted: 02/25/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND The cholesterol esterifying enzyme, lecithin:cholesterol acyltransferase (LCAT), plays a key role in HDL maturation and remodeling. Myeloperoxidase (MPO) may compromise LCAT enzymatic activity. We tested the extent to which plasma LCAT activity is altered in acute myocardial infarction (MI) in conjunction with abnormal MPO levels. We also assessed the impact of LCAT and MPO on newly developed major adverse cardiovascular events (MACE). METHODS Two-hundred one consecutive patients referred for acute chest pain of whom 134 had MI (95 with ST-elevation) participated. Forty-five new MACE were ascertained during 1203 (range 13-1745) days of follow-up among 185 patients. Plasma LCAT activity was measured using an exogenous substrate assay. MPO mass was assayed by chemiluminescent microparticle immunoassay. RESULTS Plasma LCAT activity was decreased by 15%, coinciding with 7-fold increased MPO levels in acute MI patients vs. patients with non-cardiac chest pain (p < 0.001 for both; correlation: r = -0.343, p < 0.001). MI at admission was associated independently with both lower plasma LCAT activity and higher MPO (age- and sex-adjusted odds ratio per 1 SD increment: 0.46 (95% CI, 0.31-0.68), p < 0.001 and 7.58 (95% CI, 3.34-17.11), p < 0.001, respectively). In an analysis with LCAT and MPO together these associations were modestly attenuated. MPO mass (hazard ratio: 1.59 (95% CI, 1.15-2.19), p = 0.004), but not LCAT activity (hazard ratio: 0.87 (95% CI, 0.65-1.19), p = 0.39), predicted newly manifest MACE. CONCLUSION In acute MI patients, plasma LCAT activity is decreased coinciding with increased MPO levels. Higher MPO but not lower LCAT activity prospectively predicts adverse cardiac outcome.
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Dullaart RPF, Annema W, Tio RA, Tietge UJF. The HDL anti-inflammatory function is impaired in myocardial infarction and may predict new cardiac events independent of HDL cholesterol. Clin Chim Acta 2014; 433:34-8. [PMID: 24613518 DOI: 10.1016/j.cca.2014.02.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND Intrinsic functional properties of high density lipoproteins (HDL) are considered to be physiologically important for atheroprotection. We compared the HDL anti-inflammatory capacity between patients with acute myocardial infarction (MI) and patients with non-cardiac chest pain, and prospectively determined the association of new major adverse cardiovascular events (MACE) with this metric of HDL function. METHODS A prospective study was carried out in 93 patients referred for acute chest pain (65 patients with acute MI). The HDL anti-inflammatory capacity was determined as the ability to suppress tumor necrosis factor-α-induced vascular cell adhesion molecule-1 mRNA expression in endothelial cells in vitro. RESULTS Acute MI at admission was associated with impaired HDL anti-inflammatory capacity (p=0.001), even after adjustment for HDL cholesterol and apolipoprotein A-I (p=0.003). Twenty nine MACE were ascertained during a median follow-up of 1210 (910-1679) days. New MACE was associated with impaired HDL anti-inflammatory capacity (hazard ratio: 1.80 (1.17-2.77) per SD change, p=0.007) in age, sex, HDL cholesterol and apolipoprotein-AI adjusted analysis. CONCLUSIONS The ability of HDL to attenuate endothelial inflammation is impaired in acute MI, and this metric of HDL function may serve as a predictor of new MACE, even independent of HDL cholesterol and apolipoprotein A-I.
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Dikkers A, Annema W, de Boer JF, Iqbal J, Hussain MM, Tietge UJF. Differential impact of hepatic deficiency and total body inhibition of MTP on cholesterol metabolism and RCT in mice. J Lipid Res 2014; 55:816-25. [PMID: 24511105 DOI: 10.1194/jlr.m042986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Because apoB-containing lipoproteins are pro-atherogenic and their secretion by liver and intestine largely depends on microsomal triglyceride transfer protein (MTP) activity, MTP inhibition strategies are actively pursued. How decreasing the secretion of apoB-containing lipoproteins affects intracellular rerouting of cholesterol is unclear. Therefore, the aim of the present study was to determine the effects of reducing either systemic or liver-specific MTP activity on cholesterol metabolism and reverse cholesterol transport (RCT) using a pharmacological MTP inhibitor or a genetic model, respectively. Plasma total cholesterol and triglyceride levels were decreased in both MTP inhibitor-treated and liver-specific MTP knockout (L-Mttp(-/-)) mice (each P < 0.001). With both inhibition approaches, hepatic cholesterol as well as triglyceride content was consistently increased (each P < 0.001), while biliary cholesterol and bile acid secretion remained unchanged. A small but significant decrease in fecal bile acid excretion was observed in inhibitor-treated mice (P < 0.05), whereas fecal neutral sterol excretion was substantially increased by 75% (P < 0.001), conceivably due to decreased intestinal absorption. In contrast, in L-Mttp(-/-) mice both fecal neutral sterol and bile acid excretion remained unchanged. However, while total RCT increased in inhibitor-treated mice (P < 0.01), it surprisingly decreased in L-Mttp(-/-) mice (P < 0.05). These data demonstrate that: i) pharmacological MTP inhibition increases RCT, an effect that might provide additional clinical benefit of MTP inhibitors; and ii) decreasing hepatic MTP decreases RCT, pointing toward a potential contribution of hepatocyte-derived VLDLs to RCT.
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van Stijn CMW, Kim J, Barish GD, Tietge UJF, Tangirala RK. Adiponectin expression protects against angiotensin II-mediated inflammation and accelerated atherosclerosis. PLoS One 2014; 9:e86404. [PMID: 24466075 PMCID: PMC3899253 DOI: 10.1371/journal.pone.0086404] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 12/09/2013] [Indexed: 12/15/2022] Open
Abstract
Adiponectin (APN), an adipocytokine produced by adipose tissue, exerts pleiotropic actions regulating inflammation, metabolism and vascular homeostasis. APN levels are inversely correlated with obesity, type-2 diabetes, hypertension and cardiovascular disease. Although renin angiotensin system (RAS) activation in these interrelated metabolic syndrome components increases angiotensin II (AngII) levels leading to vascular damage, it is unknown whether APN under these conditions provides atheroprotection. We investigated whether increasing plasma APN provides atheroprotection in a hypertensive and accelerated atherosclerosis model. Using adenoviral gene transfer, sustained APN expression increased plasma levels of total and high-molecular weight APN, leading to a significant elevation of plasma HDL-cholesterol (HDL-C). Elevated APN levels were strongly atheroprotective, yet had no impact on blood pressure. Notably, gene expression analyses revealed that APN significantly inhibited the expression of pro-inflammatory and atherogenic genes while it increased the expression of the anti-inflammatory cytokine, IL-10 and the cholesterol efflux transporters, ABCA1 and ABCG1 in the artery wall. These findings suggest that increasing APN levels may be an effective therapeutic strategy to inhibit vascular inflammation and accelerated atherosclerosis associated with RAS activation in the metabolic syndrome.
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Triolo M, Annema W, de Boer JF, Tietge UJF, Dullaart RPF. Simvastatin and bezafibrate increase cholesterol efflux in men with type 2 diabetes. Eur J Clin Invest 2014; 44:240-8. [PMID: 24325778 DOI: 10.1111/eci.12226] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 12/07/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND The importance of functional properties of high-density lipoproteins (HDL) for atheroprotection is increasingly recognized. We determined the impact of lipid-lowering therapy on 3 key HDL functionalities in Type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS A placebo-controlled, randomized cross-over study (three 8-week treatment periods with simvastatin (40 mg daily), bezafibrate (400 mg daily), alone and in combination) was carried out in 14 men with T2DM. Cholesterol efflux was determined using human THP-1 monocyte-derived macrophages, HDL antioxidative capacity was measured as inhibition of low-density lipoprotein oxidation in vitro, and HDL anti-inflammatory capacity was assessed as suppression of thrombin-induced monocyte chemotactic protein 1 expression in human umbilical vein endothelial cells. Pre-β-HDL was assayed using crossed immunoelectrophoresis. RESULTS While cholesterol efflux increased in response to simvastatin, bezafibrate and combination treatment (+12 to +23%; anova, P = 0.001), HDL antioxidative capacity (P = 0.23) and HDL anti-inflammatory capacity (P = 0.15) did not change significantly. Averaged changes in cellular cholesterol efflux during active treatment were correlated positively with changes in HDL cholesterol, apoA-I and pre-β-HDL (P < 0.05 to P < 0.001). There were no inter-relationships between changes in the three HDL functionalities during treatment (P > 0.10). Changes in HDL antioxidative capacity and anti-inflammatory capacity were also unrelated to changes in HDL cholesterol and apoA-I, while changes in HDL antioxidative capacity were related inversely to pre-β-HDL (P < 0.05). CONCLUSION Simvastatin and bezafibrate increase cholesterol efflux, parallel to HDL cholesterol and apoA-I responses. The antioxidative and anti-inflammatory properties of HDL are not to an important extent affected by these therapeutic interventions.
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Lichtenstein L, Serhan N, Annema W, Combes G, Robaye B, Boeynaems JM, Perret B, Tietge UJF, Laffargue M, Martinez LO. Lack of P2Y13 in mice fed a high cholesterol diet results in decreased hepatic cholesterol content, biliary lipid secretion and reverse cholesterol transport. Nutr Metab (Lond) 2013; 10:67. [PMID: 24476490 PMCID: PMC4029266 DOI: 10.1186/1743-7075-10-67] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/30/2013] [Indexed: 01/11/2023] Open
Abstract
Background The protective effect of HDL is mostly attributed to their metabolic function in reverse cholesterol transport (RCT), a process whereby excess cellular cholesterol is taken up from peripheral cells, processed in HDL particles, and later delivered to the liver for further metabolism and biliary secretion. Mechanistically, the purinergic P2Y13 ADP-receptor is involved in hepatic HDL endocytosis (i.e., uptake of both HDL protein + lipid moieties), which is considered an important step of RCT. Accordingly, chow-fed P2Y13 knockout (P2Y13-/-) mice exhibit lower hepatic HDL uptake, which translates into a decrease of hepatic free cholesterol content and biliary cholesterol and phospholipid secretion. Findings The aim of this study was to determine the effect of high cholesterol diet (HCD) in P2Y13-/- mice, in order to mimic high dietary cholesterol intake, which is a major cause of dyslipidemia in humans. As previously reported with chow-diet, HCD did not affect plasma lipid levels in P2Y13-/- compared with control mice but decreased hepatic free and esterified cholesterol content (p < 0.05, P2Y13-/- versus control). Interestingly, biliary lipid secretion and macrophages-to-feces RCT were more dramatically impaired in P2Y13-/- mice fed a HCD than chow-diet. HCD did not enhance atherosclerosis in P2Y13-/- compared with control mice. Conclusion This study demonstrates that high dietary cholesterol intake accentuated the metabolic phenotype of P2Y13-/- mice, with impaired hepatobiliary RCT. Although other animal models might be required to further evaluate the role of P2Y13 receptor in atherosclerosis, P2Y13 appears a promising target for therapeutic intervention aiming to stimulate RCT, particularly in individuals with lipid-rich diet.
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