scholarly journals Scavenging dicarbonyls with 5’-O-pentyl-pyridoxamine improves insulin sensitivity and reduces atherosclerosis through modulating inflammatory Ly6Chi monocytosis and macrophage polarization

2019 ◽  
Author(s):  
Jiansheng Huang ◽  
Patricia G. Yancey ◽  
Linda S. May-Zhang ◽  
Huan Tao ◽  
Youmin Zhang ◽  
...  

BackgroundLipid peroxidation products impair HDL function and contribute to the development of atherosclerosis. Ours and other studies have shown that reactive dicarbonyls such as Isolevuglandins (IsoLG) and malondialdehyde (MDA), crosslink apoAI and impair the ability of HDL to promote cholesterol efflux. We examined whether scavenging of reactive dicarbonyls protects against the development of insulin resistance and atherosclerosis.Methods and ResultsHere, we found that 5’-O-pentyl-pyridoxamine (PPM), a potent scavenger of reactive dicarbonyls, abolished MDA-mediated crosslinking of apoAI in HDL by 80 % (P<0.05). In addition, PPM prevented the reduction in cholesterol efflux capacity of MDA treated HDL and preserved the cholesterol efflux capacity of MPO-modified HDL in Apoe−/− macrophages. Furthermore, PPM significantly improved the cholesterol efflux capacity and PON1 activity of HDL in Ldlr−/− mice (P<0.05), indicating that PPM protects HDL from modifications by reactive dicarbonyls and maintains HDL function in vivo. Importantly, PPM improved hyperglycemia and insulin sensitivity in male Ldlr−/− mice. Administration of 1 mg/mL of PPM, versus 1 mg/mL of the nonreactive analogue PPO, to Ldlr−/− mice consuming a western diet (WD) for 16 weeks reduced the extent of proximal aortic atherosclerosis by 48% and by 46% (P<0.05) in female and male Ldlr−/− mice. PPM also reduced the extent of en face aortic lesion by 52% in male Ldlr−/− mice. In addition, PPM reduced pro-inflammatory enzyme MPO expression by 57.5% and the number of TUNEL positive cells by 52% (P<0.01) in atherosclerotic lesions of Ldlr−/− mice. Immunohistochemistry studies revealed that PPM reduced the lesion macrophage content by 55% (P<0.05). Importantly, PPM increased M2 marker Arg1+ in macrophages of lesions and reduced the number of blood pro-inflammatory Ly6Chi monocytes and the ratio between Ly6Chi and Ly6Clow, but not the numbers of Ly6Clow, neutrophils in Ldlr−/− mice. Similarly, treatment of Apoe−/− mice on a WD for 16 weeks with PPM significantly reduced the extent of atherosclerotic lesions and also enhanced plaque stability as evidenced by a 47% increase in fibrous cap thickness and a 64.7% reduction in necrotic core area.ConclusionsReactive dicarbonyl scavenging with PPM in vivo preserves HDL function which improves insulin sensitivity and decreases atherosclerosis development. These results support the therapeutic potential of reactive dicarbonyl scavenging in the treatment of insulin resistance and atherosclerotic cardiovascular disease.

Cholesterol ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Remco Franssen ◽  
Alinda W. M. Schimmel ◽  
Sander I. van Leuven ◽  
Simone C. S. Wolfkamp ◽  
Erik S. G. Stroes ◽  
...  

HDL provides atheroprotection by facilitating cholesterol efflex from lipid-laden macrophages in the vessel wall. In vitro studies have suggested impaired efflux capacity of HDL following inflammatory changes. We assessed the impact of acute severe sepsis and mild chronic inflammatory disease on the efflux capacity of HDL. We hypothesize that a more severe inflammatory state leads to stronger impaired cholesterol efflux capacity. Using lipid-laden THP1 cells and fibroblasts we were able to show that efflux capacity of HDL from both patients with severe sepsis or with Crohn's disease (active or in remission), either isolated using density gradient ultracentrifugation or using apoB precipitation, was not impaired. Yet plasma levels of HDL cholesterol and apoA-I were markedly lower in patients with sepsis. Based on the current observations we conclude that inflammatory disease does not interfere with the capacity of HDL to mediate cholesterol efflux. Our findings do not lend support to the biological relevance of HDL function changes in vitro.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Jiansheng Huang ◽  
Patricia Yancey ◽  
Lei Ding ◽  
Youmin Zhang ◽  
John Oates ◽  
...  

Background: Lipid peroxidation products impair the cholesterol efflux capacity of high-density lipoprotein (HDL) and promote the development of atherosclerosis. The impact of inhibition of malondialdehyde (MDA)-HDL adduct formation by scavengers on HDL function and whether small molecule aldehyde scavengers protect against the development of atherosclerosis was examined. Methods and Results: Western blot analysis of ApoAI revealed that the amount of ApoAI crosslinking increased with MDA concentration. In the presence of LPS, MDA-HDL (HDL modified by 1mM MDA) versus control HDL stimulated 2- and 1.8-fold more expression of TNF-α and IL-1β in Apoe-/- macrophages demonstrating that MDA-HDL has reduced anti-inflammatory function. HDL-mediated macrophage cholesterol efflux was decreased by ~ 42%, 55%, 70%, and 80%, respectively, for HDL modified with 0.125 mM, 0.25 mM, 0.5 mM, and 1mM MDA, demonstrating that MDA modification of HDL affects its cholesterol efflux capacity in a dose dependent manner. Analysis by Western blot demonstrated that 5mM of salicylamine (SAM) and 5mM of pentylpyridoxamine (PPM), γ-ketoaldehyde scavengers, attenuated MDA mediated crosslinking of apoA-I in HDL (molar ratio of MDA and HDL is 1:5) by 60% and 80 % (P<0.05), respectively. Both SAM and PPM maintained the cholesterol efflux capacity of MDA treated HDL in Apoe-/- macrophages. In addition, pretreatment of LDL with SAM prevented MDA-ApoB adduct formation, and compared to incubation with LDL containing MDA-ApoB adducts, SAM treatment resulted in 57% less cholesterol accumulation in J774 macrophages. Importantly, administration of the ketoaldehyde scavenger, SAM, versus the nonreactive analogue, 4-SAM, to Apoe-/- mice consuming a Western diet for 16 weeks reduced the extent of proximal aortic atherosclerosis by 28% (P<0.05). Conclusions: Treatment with salicylamine, a γ-ketoaldehyde scavenger: 1) inhibits MDA-ApoA1 adduct formation thereby preserving HDL cholesterol efflux capacity; 2) prevents MDA-apoB100 formation resulting in less macrophage cholesterol accumulation; 3) reduces atherosclerosis in Apoe -/- mice. These results support the therapeutic potential of salicylamine in the treatment of atherosclerotic cardiovascular disease.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Himani Thakkar ◽  
Vinnyfred Vincent ◽  
Sakshi Sukhla ◽  
Manraj Sra ◽  
Uma Kanga ◽  
...  

Abstract Background Bariatric surgery can alleviate cardiovascular risk via effects on cardiovascular disease (CVD) risk factors such as diabetes mellitus, hypertension, and dyslipidemia. Our study aimed to assess the cholesterol efflux capacity (CEC) of HDL as a negative risk factor for CVD in individuals with obesity and identify the factors associated with improvement in CEC 3 months following bariatric surgery. Methods We recruited 40 control individuals (mean BMI of 22.2 kg/m2) and 56 obese individuals (mean BMI of 45.9 kg/m2). The biochemical parameters, inflammatory status and CEC of HDL was measured for the obese individuals before bariatric surgery and at 3 months after surgery. The CEC was measured using a cell-based cholesterol efflux system of BODIPY-cholesterol-labelled THP-1 macrophages. Results A significant reduction in BMI (− 17%, p < 0.001), resolution of insulin sensitivity (HOMA2-IR = − 23.4%, p = 0.002; Adipo IR = − 16%, p = 0.009) and inflammation [log resistin = − 6%, p = 0.07] were observed 3 months post-surgery. CEC significantly improved 3 months after surgery [Pre: 0.91 ± 0.13; Post: 1.02 ± 0.16; p = 0.001] despite a decrease in HDL-C levels. The change in CEC correlated with the change in apo A-I (r = 0.39, p = 0.02) and adiponectin levels (r = 0.35, p = 0.03). Conclusion The results suggest that improvements in CEC, through improvement in adipose tissue health in terms of adipokine secretion and insulin sensitivity could be an important pathway in modulating obesity-related CVD risk.


Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1407
Author(s):  
Robert K. Clemens ◽  
Monika Hunjadi ◽  
Andreas Ritsch ◽  
Lucia Rohrer ◽  
Thomas O. Meier ◽  
...  

Background: Cholesterol efflux is an important mechanism by which high-density lipoproteins (HDLs) protect against cardiovascular disease. As peripheral artery disease (PAD) is associated with high mortality rates, mainly due to cardiovascular causes, we investigated whether cholesterol efflux capacity (CEC) of apolipoprotein B (apoB)-depleted plasma, a widely used surrogate of HDL function, may serve as a predictive marker for mortality in this patient population. Methods: In this prospective single-center study (median follow-up time: 9.3 years), apoB-containing lipoproteins were precipitated from plasma of 95 patients with PAD and incubated with J744-macrophages, which were loaded with radiolabeled cholesterol. CEC was defined as the fractional radiolabel released during 4 h of incubation. Results: Baseline CEC was lower in PAD patients that currently smoked (p = 0.015) and had a history of myocardial infarction (p = 0.011). Moreover, CEC showed a significant correlation with HDL-cholesterol (p = 0.003) and apolipoprotein A-I levels (p = 0.001) as well as the ankle-brachial index (ABI, p = 0.018). However, CEC did not differ between survivors and non-survivors. Neither revealed Kaplan–Meier and Cox regression analyses any significant association of CEC with all-cause mortality rates. Conclusion: Taken together, CEC is associated with ABI but does not predict all-cause mortality in patients with PAD.


2005 ◽  
Vol 289 (4) ◽  
pp. H1335-H1342 ◽  
Author(s):  
Harish Vasudevan ◽  
Hong Xiang ◽  
John H. McNeill

Differences in gender are in part responsible for the development of insulin resistance (IR) and associated hypertension. Currently, it is unclear whether these differences are dictated by gender itself or by the relative changes in plasma estrogen and/or testosterone. We investigated the interrelationships between testosterone and estrogen in the progression of IR and hypertension in vivo in intact and gonadectomized fructose-fed male rats. Treatment with estrogen significantly reduced the testosterone levels in both normal chow-fed and fructose-fed rats. Interestingly, fructose feeding induced a relative increase in estradiol levels, which did not affect IR in both intact and gonadectomized fructose-fed rats. However, increasing the estrogen levels improved insulin sensitivity in both intact and gonadectomized fructose-fed rats. In intact males, fructose feeding increased the blood pressure (140 ± 2 mmHg), which was prevented by estrogen treatment. However, the blood pressure in the fructose-fed estrogen rats (125 ± 1 mmHg) was significantly higher than that of normal chow-fed (113 ± 1 mmHg) and fructose-fed gonadectomized rats. Estrogen treatment did not affect the blood pressure in gonadectomized fructose-fed rats (105 ± 2 mmHg). These data suggest the existence of a threshold value for estrogen below which insulin sensitivity is unaffected. The development of hypertension in this model is dictated solely by the presence or absence of testosterone. In summary, the development of IR and hypertension is governed not by gender per se but by the interactions of specific sex hormones such as estrogen and testosterone.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Larbi Krimbou ◽  
Ravi Jahagirdar ◽  
Dana Bailey ◽  
Anouar Hafiane ◽  
Isabelle Ruel ◽  
...  

The novel compound RVX-208 is a small molecule that upregulates the gene expression of apoA-I and raises HDL-C in non-human primates. Here, we examined the effects of oral administration of RVX-208 on serum apoA-I and HDL-C levels , HDL size distribution, and HDL function. African green monkeys received RVX-208 (7.5, 15 and 30 mg/kg; twice daily and 60 mg/kg; once daily) or vehicle control for 28, 42, and 63 days. We report that RVX-208 chronic treatment resulted in a highly significant increase in the average of serum apoA-I and HDL-C levels (57% and 92%, respectively). Interestingly, RVX-208 treatment modified the distribution of HDL particle size causing a significant increase in preβ1-LpA-I and larger α1-LpA-I species. The ability of serum to promote cholesterol efflux via ABCA1, ABCG1 or SR-BI-dependent pathways in a cell culture model was significantly increased by RVX-208. The phase Ia safety and pharmacokinetic human study comprised of a total of 80 subjects. In the multiple ascending dose arm, 24 participants were randomly assigned to 3 cohorts of 8 healthy volunteers (6 active and 2 placebo), and received oral administration of RVX-208 at 2, 3 and 8 mg/kg per day or placebo for 7 days. The compound was well tolerated and had good oral absorption meeting the objectives of safety and pharmacokinetics. ApoA-I, HDL-C, HDL size distribution and ABCA1-dependent cholesterol efflux were assessed at days 1 (predose) and 7. The percent change from baseline to day 7 for apoA-I was 11% higher (P = 0.03) in the RVX-208 treated participants compared to placebo. Interestingly, preβ1-LpA-I change was 30% (P = 0.02) higher in the actively treated group and was found to strongly correlate with increased apoA-I levels (R2 = 0.72). Furthermore, ABCA1-dependent cholesterol efflux change was 10% higher (P = 0.03) and was found to correlate with increased preβ1-LpA-I . Taken together, these pharmacodynamic data from human healthy volunteers show consistent trends in apoA-I production and HDL functionality, supporting the findings in the African green monkey. Further investigation of the effect of RVX-208 on the HDL metabolic pathway is ongoing in humans and animals to establish the mechanisms of action and therapeutic potential in treating atherosclerotic cardiovascular disease.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Jennifer L Ford ◽  
Raymond C Boston ◽  
Rachel E Walker ◽  
Gregory C Shearer

Background: Insulin resistance is a major contributor to metabolic syndrome, disrupting both glucose and non-esterified fatty acid (NEFA) dynamics through ineffective glucose clearance and decreased suppression of lipid droplet lipolysis. The minimal model of glucose dynamics is used for glycemic insulin sensitivity however it does not measure adipocyte insulin sensitivity, the primary determinant of plasma NEFA. An in-vivo approach to measuring adipocyte insulin sensitivity using NEFA is employed, comparing healthy and metabolic syndrome subjects. Both the models are employed to estimate insulin sensitivity and validate the NEFA approach. Objective: To test the use of NEFA kinetics to measure adipocyte insulin sensitivity compared to the glucose minimal model. Approach and results: Metabolic syndrome (n=56) and optimally healthy (n=14) subjects underwent a frequently sampled intravenous glucose tolerance test, and plasma analyzed for insulin, glucose, and NEFA. Insulin sensitivity ( S I ) and glucose effectiveness ( S G ) were calculated from the glucose minimal model. S I was 1.7 (mU/L) -1 min -1 and 0.40 (mU/L) -1 /min -1 and S G was 0.027 min -1 and 0.017 min -1 for the healthy and metabolic syndrome groups, respectively, indicating substantial glycemic insulin resistance in the latter. A model using glucose as the driver for NEFA kinetics was then applied. We found the initial rate of NEFA utilization by tissues (NU) was less, but the threshold glucose (tG) and glucose concentration required for a unit change in lipolysis inhibition ( G i ) were greater in metabolic syndrome verses healthy (NU: 0.050[0.045, 0.057] vs. 0.068[0.054, 0.086] p=0.03; tG: 6.7[6.2, 7.2] vs. 5.0[4.3, 5.9] p=0.001; G i : 0.30[0.25, 0.35] vs. 0.17[0.07, 0.27] p=0.02). No differences were found in initial rate of NEFA production or glucose utilization. Conclusion: Our results indicate that suppression of lipid-droplet lipolysis requires greater stimulus in metabolic syndrome compared to insulin sensitive adipocytes. Further, the rate of NEFA removal is less in metabolic syndrome. These results reveal components of insulin sensitivity not demonstrated by the glucose model. The NEFA model provides a measurement of adipocyte insulin sensitivity not captured by glycemic indices.


2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Mathieu R Brodeur ◽  
David Rhainds ◽  
Daniel Charpentier ◽  
Téodora Mihalache-Avram ◽  
Cyrille Maugeais ◽  
...  

Introduction: A potential approach to reduce CV risk is to increase HDL-C levels. This could be achieved by reducing cholesteryl ester transfer protein (CETP) activity. Dalcetrapib, which modulates CETP activity by changing its conformation and raises HDL-C without inhibiting CETP-induced pre-β-HDL formation in humans, was shown to decrease progression of atherosclerosis in rabbits. Hypothesis: Investigate the modifications of HDL particle size distribution and cholesterol efflux capacity of serum produced by dalcetrapib in normocholesterolemic rabbits. Methods: New Zealand white rabbits were treated with dalcetrapib (300 mg/kg as food admix) or placebo for 14 days. We evaluated CETP conformation and mass by ELISAs (including antibodies sensitive to conformational change), CETP activity by fluorescent lipid transfer, lipid profile and apoA-I distribution in HDL subclasses by 2D-non denaturing gradient gels (2D-NDGGE). Cholesterol efflux capacity of rabbit sera was determined after loading cells with 3 H-free cholesterol, using HepG2 hepatocytes to measure SR-BI-dependent efflux and by inducing ABCA1 or ABCG1 expression in BHK cells. Results: Dalcetrapib modified the conformation of rabbit CETP in vitro and in vivo and, after 14 days, this was associated with increased CETP mass (+50%, p<0.001) and reduced CETP activity (-86%, p<0.001). Total cholesterol was increased with dalcetrapib (+178%, p<0.001), due to a higher HDL-C level. In contrast, dalcetrapib reduced LDL-C and triglycerides by 41% (p<0.01) and 48% (p<0.001). Serum analysis by 2D-NDGGE showed that total rabbit apoA-I was increased 1.7- fold in animals treated with dalcetrapib. This was associated with an increase in large HDL but also in small α-migrating HDL with pre-β-HDL size. Cholesterol efflux assays showed that ABCA1-, ABCG1- and SR-BI-dependent efflux were all increased in dalcetrapib-treated rabbits (+24%, p=0.038; +21%, p=0.021; +44%, p<0.001). Conclusion: Modulation of CETP activity and conformation by dalcetrapib increases HDL-C and apoA-I levels and affects apoA-I distribution in HDL subclasses. These changes are associated with increased cholesterol efflux capacity, suggesting that HDL functionality is preserved in dalcetrapib-treated chow-fed rabbits.


2021 ◽  
Author(s):  
Xingjing Liu ◽  
Peng Sun ◽  
Qingzhao Yuan ◽  
Jinyang Xie ◽  
Ting Xiao ◽  
...  

Calcium/calmodulin-dependent serine protein kinase (CASK) is involved in the secretion of insulin vesicles in pancreatic β-cells. The present study revealed a new <i>in vivo </i>role of CASK in glucose homeostasis during the progression of type 2 diabetes mellitus (T2DM). A Cre-loxP system was used to specifically delete the <i>Cask </i>gene in mouse β-cells (βCASKKO), and the glucose metabolism was evaluated in <a>βCASKKO</a> mice fed a normal chow diet (ND) or a high-fat diet (HFD). ND-fed mice exhibited impaired insulin secretion in response to glucose stimulation. Transmission electron microscopy showed significantly reduced numbers of insulin granules at or near the cell membrane in the islets of βCASKKO mice. By contrast, HFD-fed βCASKKO mice showed reduced blood glucose and a partial relief of hyperinsulinemia and insulin resistance when compared to HFD-fed wildtype mice. The IRS1/PI3K/AKT signaling pathway was upregulated in the adipose tissue of HFD-βCASKKO mice. These results indicated that knockout of the <i>Cask</i> gene in β cells had a diverse effect on glucose homeostasis: reduced insulin secretion in ND-fed mice, but improves insulin sensitivity in HFD-fed mice. Therefore, CASK appears to function in the insulin secretion and contributes to hyperinsulinemia and insulin resistance during the development of obesity-related T2DM.


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