scholarly journals Cholesterol Homeostasis: An In Silico Investigation into How Aging Disrupts Its Key Hepatic Regulatory Mechanisms

Biology ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 314
Author(s):  
Amy Elizabeth Morgan ◽  
Mark Tomás Mc Auley
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Enzymatic Reactions ◽  
Low Density ◽  
Acetyl Coa ◽  
Alcoholic Fatty Liver ◽  
Age Related ◽  
Intracellular Cholesterol ◽  
The Impact

The dysregulation of intracellular cholesterol homeostasis is associated with several age-related diseases, most notably cardiovascular disease (CVD). Research in this area has benefitted from using computational modelling to study the inherent complexity associated with the regulation of this system. In addition to facilitating hypothesis exploration, the utility of modelling lies in its ability to represent an array of rate limiting enzymatic reactions, together with multiple feedback loops, which collectively define the dynamics of cholesterol homeostasis. However, to date no model has specifically investigated the effects aging has on this system. This work addresses this shortcoming by explicitly focusing on the impact of aging on hepatic intracellular cholesterol homeostasis. The model was used to investigate the experimental findings that reactive oxygen species induce the total activation of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR). Moreover, the model explored the impact of an age-related decrease in hepatic acetyl-CoA acetyltransferase 2 (ACAT2). The model suggested that an increase in the activity of HMGCR does not have as significant an impact on cholesterol homeostasis as a decrease in hepatic ACAT2 activity. According to the model, a decrease in the activity of hepatic ACAT2 raises free cholesterol (FC) and decreases low-density lipoprotein cholesterol (LDL-C) levels. Increased acetyl CoA synthesis resulted in a reduction in the number of hepatic low-density lipoprotein receptors, and increased LDL-C, FC, and cholesterol esters. The rise in LDL-C was restricted by elevated hepatic FC accumulation. Taken together these findings have important implications for healthspan. This is because emerging clinical data suggest hepatic FC accumulation is relevant to the pathogenesis of non-alcoholic fatty liver disease (NAFLD), which is associated with an increased risk of CVD. These pathophysiological changes could, in part, help to explain the phenomenon of increased mortality associated with low levels of LDL-C which have been observed in certain studies involving the oldest old (≥85 years).

scholarly journals Deleting myeloid IL-10 receptor signalling attenuates atherosclerosis in LDLR-/- mice by altering intestinal cholesterol fluxes

2016 ◽  
Vol 116 (09) ◽  
pp. 565-577 ◽  
Author(s):  
Gemma Brufau ◽  
Marion J. J. Gijbels ◽  
Ine M. J. Wolfs ◽  
Saskia van der Velden ◽  
Chantal C. H. Pöttgens ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Cholesterol Metabolism ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Liver Cholesterol ◽  
Specific Cell ◽  
Low Density ◽  
Atherosclerosis Development ◽  
Deficient Mice

SummaryInflammatory responses and cholesterol homeostasis are interconnected in atherogenesis. Interleukin (IL)-10 is an important anti-inflammatory cytokine, known to suppress atherosclerosis development. However, the specific cell types responsible for the atheroprotective effects of IL-10 remain to be defined and knowledge on the actions of IL-10 in cholesterol homeostasis is scarce. Here we investigated the functional involvement of myeloid IL-10-mediated atheroprotection. To do so, bone marrow from IL-10 receptor 1 (IL-10R1) wild-type and myeloid IL-10R1-deficient mice was transplanted to lethally irradiated female LDLR-/- mice. Hereafter, mice were given a high cholesterol diet for 10 weeks after which atherosclerosis development and cholesterol metabolism were investigated. In vitro, myeloid IL-10R1 deficiency resulted in a pro-inflammatory macrophage phenotype. However, in vivo significantly reduced lesion size and severity was observed. This phenotype was associated with lower myeloid cell accumulation and more apoptosis in the lesions. Additionally, a profound reduction in plasma and liver cholesterol was observed upon myeloid IL-10R1 deficiency, which was reflected in plaque lipid content. This decreased hypercholesterolaemia was associated with lowered very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels, likely as a response to decreased intestinal cholesterol absorption. In addition, IL-10R1 deficient mice demonstrated substantially higher faecal sterol loss caused by increased non-biliary cholesterol efflux. The induction of this process was linked to impaired ACAT2-mediated esterification of liver and plasma cholesterol. Overall, myeloid cells do not contribute to IL-10-mediated atheroprotection. In addition, this study demonstrates a novel connection between IL-10-mediated inflammation and cholesterol homeostasis in atherosclerosis. These findings make us reconsider IL-10 as a beneficial influence on atherosclerosis.Supplementary Material to this article is available online at www.thrombosis-online.com.

scholarly journals Effects of Age, Gender, and Menopausal Status on Small Dense Low-Density Lipoprotein Cholesterol and Low-Density Lipoprotein Cholesterol Fractions; JMS-II Cohort Study

2020 ◽  
Author(s):  
Toshihide Izumida ◽  
Yosikazu Nakamura ◽  
Yukihiro Sato ◽  
Shizukiyo Ishikawa
Keyword(s):  
Cohort Study ◽  
Postmenopausal Women ◽  
Low Density Lipoprotein ◽  
Menopausal Status ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Age Related ◽  
Effect Of Age

Abstract Background:Small dense low-density lipoprotein cholesterol (sdLDL-C) might be a better cardiovascular disease (CVD) indicator than low-density lipoprotein cholesterol (LDL-C); however, details regarding its epidemiology remain elusive. The present study aimed at evaluating the effect of age, gender, and menopausal status on sdLDL-C levels and sdLDL-C/LDL-C ratio in the Japanese population.Methods:We examined the baseline cross-sectional data from the Jichi Medical School-II Cohort Study, including 5,208 participants (2,397 men and 2,811 women). To assess age-related trends, the sdLDL-C and sdLDL-C/LDL-C ratios were plotted against gender. We evaluated the effect of age and menopausal status using multiple linear regression analysis.Results:We observed that in men, the sdLDL-C levels and sdLDL-C/LDL-C ratio increased during younger adulthood, peaked at 50–54 years, and then decreased. In women, we observed relatively regular increasing trends of sdLDL-C level and sdLDL-C/LDL-C ratio until approximately 65 years, followed by a downward or pleated trend. The crossover of sdLDL-C levels for the genders occurred at 70–74 years, but we could not observe any sdLDL-C/LDL-C ratio crossover. Standardized sdLDL-C levels and sdLDL-C/LDL-C ratio in 50-year old men, premenopausal women, and postmenopausal women were 26.6, 22.7, and 27.4 mg/dL and 0.24, 0.15, and 0.23, respectively. The differences between premenopausal and postmenopausal women were significant (P<0.001).Conclusions:sdLDL-C and sdLDL-C/LDL-C ratios show different distributions by age, gender, and menopausal status with trends different from other lipids. A subgroup-specific approach would be necessary to implement sdLDL-C for CVD prevention strategies, fully considering age-related trends, gender differences, and menopausal status.

scholarly journals Evaluation of hydrated extract of phaseolus Vulgaris L. (bean plant) on hypoglycemia and hypolipidemic in streptozotocin-induced diabetic albino Wistar rats

2019 ◽  
Vol 10 (4) ◽  
pp. 3704-3710
Author(s):  
Helisha Ruth Obonyo ◽  
Senthemarai Selvi V
Keyword(s):  
Phaseolus Vulgaris ◽  
Blood Serum ◽  
Common Bean ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Diabetic Rats ◽  
Low Density ◽  
Phaseolus Vulgaris L ◽  
Reference Drug ◽  
The Impact

The current research was intended to comprehend hypoglycemic and anti-lipidaemic exercises of hydrated common bean (phaseolus Vulgaris L.) seed extracts on streptozotocin-induced diabetic albino rats. At a set portion fluctuate of 100, 200,300 mg/kg body weight of common bean extracts was orally directed as one portion for every day to polygenic disorder rats for a measure of thirty days. The impact of P.vulgaris L. on hypoglycemic, glycosylated hemoprotein (HbA1c) and blood serum lipid profile (Total cholesterin), Triglyceride (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), High-density lipoprotein (HDL)) in plasma were estimated in the regular and diabetic induced rat. The outcomes demonstrated that quick glucose,serum TC, TG, LDL, VLDL, levels were significantly (p<0.05) attenuate, while blood serum HDL, the level was extensively (p<0.05) upgraded inside the diabetic rats. The inconclusive amount of pace of 300 mg/kg is more reasonable than that of a hundred mg/kg. Our examination so shows that Phaseolus vulgaris L has a powerful adversary to diabetic and anti-lipidaemic impacts on streptozotocin-induced diabetic rats, and results were comparable to reference drug glibenclamide.

Abstract 14430: Effect Modification of Statin Therapy on the Relationship of Low-density Lipoprotein Cholesterol With Incident CKD in Us Veterans

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Jui-Ting Hsiung ◽  
Maria Marroquin ◽  
Kamyar Kalantar-Zadeh
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Us Veterans ◽  
The Impact ◽  
Statin Use

Background: Studies suggests that in the general population, hyperlipidemia may confer higher risk of developing chronic kidney disease (CKD). But, there is conflicting data as to whether statins can protect renal function or slow renal degradation. We sought to examine the impact of statins on the association of low-density lipoprotein cholesterol (LDL) and risk of incident CKD. Methods: Our cohort included 1,439,756 US veterans without chronic kidney disease (CKD), but with LDL measured between 2004-2006, who were followed until 2014. Incident CKD was defined as over 3 estimated glomerular filtration rate (eGFR) measurements <60 mL/min/1.73m 2 at least 90 days apart. Patients with a statin prescription at the time of LDL measurement were identified. Cox models were used to estimate the associations between LDL with incident CKD. Model adjustments include demographics, comorbidities, smoking status, prescription of fibrate or niacin, body mass index, albumin, high-density lipoprotein cholesterol, and triglycerides. Results: The cohort included 5% females, 16% African Americans, 26% diabetics, and 30% statin-users, with a mean age of 60±13 years. The median [IQR] of LDL and eGFR were 109 [88,133] mg/dL and 83 [72,94] mL/min/1.73m 2 , respectively. A J-shaped association between LDL and incident CKD were observed in both those on statin and not on a statin after adjustment. Low LDL (<70 mg/dL) was associated with a higher risk of incident CKD compared to the reference (LDL 70-<100 mg/dL) regardless of statin use. High LDL ≥160 mg/dL was associated with the highest of risks of incident CKD (HR: 1.08, 95% CI: 1.04, 1.13, and HR: 1.10, 95% CI: 1.07, 1.12, for statin use and no statin use, respectively). Conclusion: Both high and low LDL were associated with higher incident CKD risk independent of statin use in this US veteran cohort. Further studies are needed to understand how to manage cardiovascular disease risk by lowering LDL while simultaneously reducing risk of CKD.

scholarly journals ChREBP-Mediated Regulation of Lipid Metabolism: Involvement of the Gut Microbiota, Liver, and Adipose Tissue

2020 ◽  
Vol 11 ◽  
Author(s):  
Katsumi Iizuka ◽  
Ken Takao ◽  
Daisuke Yabe
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Gut Microbiota ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Acid Synthesis ◽  
Whole Body ◽  
Acetyl Coa ◽  
Alcoholic Fatty Liver

Carbohydrate response element-binding protein (ChREBP) plays an important role in the development of type 2 diabetes, dyslipidemia, and non-alcoholic fatty liver disease, as well as tumorigenesis. ChREBP is highly expressed in lipogenic organs, such as liver, intestine, and adipose tissue, in which it regulates the production of acetyl CoA from glucose by inducing Pklr and Acyl expression. It has recently been demonstrated that ChREBP plays a role in the conversion of gut microbiota-derived acetate to acetyl CoA by activating its target gene, Acss2, in the liver. ChREBP regulates fatty acid synthesis, elongation, and desaturation by inducing Acc1 and Fasn, elongation of long-chain fatty acids family member 6 (encoded by Elovl6), and Scd1 expression, respectively. ChREBP also regulates the formation of very low-density lipoprotein by inducing the expression of Mtp. Furthermore, it plays a crucial role in peripheral lipid metabolism by inducing Fgf21 expression, as well as that of Angptl3 and Angptl8, which are known to reduce peripheral lipoprotein lipase activity. In addition, ChREBP is involved in the production of palmitic-acid-5-hydroxystearic-acid, which increases insulin sensitivity in adipose tissue. Curiously, ChREBP is indirectly involved in fatty acid β-oxidation and subsequent ketogenesis. Thus, ChREBP regulates whole-body lipid metabolism by controlling the transcription of lipogenic enzymes and liver-derived cytokines.

scholarly journals Low‐Density Lipoprotein Cholesterol Corrected for Lipoprotein(a) Cholesterol, Risk Thresholds, and Cardiovascular Events

2020 ◽  
Vol 9 (23) ◽  
Author(s):  
Peter Willeit ◽  
Calvin Yeang ◽  
Patrick M. Moriarty ◽  
Lena Tschiderer ◽  
Stephen A. Varvel ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Clinical Care ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Content ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Low Density Lipoprotein Cholesterol ◽  
Lipoprotein A ◽  
The Impact

Background Conventional "low‐density lipoprotein cholesterol (LDL‐C)" assays measure cholesterol content in both low‐density lipoprotein and lipoprotein(a) particles. To clarify the consequences of this methodological limitation for clinical care, our study aimed to compare associations of “LDL‐C” and corrected LDL‐C with risk of cardiovascular disease and to assess the impact of this correction on the classification of patients into guideline‐recommended LDL‐C categories. Methods and Results Lipoprotein(a) cholesterol content was estimated as 30% of lipoprotein(a) mass and subtracted from “LDL‐C” to obtain corrected LDL‐C values (LDL‐C corr30 ). Hazard ratios for cardiovascular disease (defined as coronary heart disease, stroke, or coronary revascularization) were quantified by individual‐patient‐data meta‐analysis of 5 statin landmark trials from the Lipoprotein(a) Studies Collaboration (18 043 patients; 5390 events; 4.7 years median follow‐up). When comparing top versus bottom quartiles, the multivariable‐adjusted hazard ratio for cardiovascular disease was significant for “LDL‐C” (1.17; 95% CI, 1.05–1.31; P =0.005) but not for LDL‐C corr30 (1.07; 95% CI, 0.93–1.22; P =0.362). In a routine laboratory database involving 531 144 patients, reclassification of patients across guideline‐recommended LDL‐C categories when using LDL‐C corr30 was assessed. In “LDL‐C” categories of 70 to <100, 100 to <130, 130 to <190, and ≥190 mg/dL, significant proportions (95% CI) of participants were reassigned to lower LDL‐C categories when LDL‐C corr30 was used: 30.2% (30.0%–30.4%), 35.1% (34.9%–35.4%), 32.9% (32.6%–33.1%), and 41.1% (40.0%–42.2%), respectively. Conclusions “ LDL‐C” was associated with incident cardiovascular disease only when lipoprotein(a) cholesterol content was included in its measurement. Refinement in techniques to accurately measure LDL‐C, particularly in patients with elevated lipoprotein(a) levels, is warranted to assign risk to the responsible lipoproteins.

scholarly journals Lipocalin 2 Deficiency Alters Estradiol Production and Estrogen Receptor Signaling in Female Mice

Endocrinology ◽  
2012 ◽  
Vol 153 (3) ◽  
pp. 1183-1193 ◽  
Author(s):  
Hong Guo ◽  
Yuanyuan Zhang ◽  
David A. Brockman ◽  
Wendy Hahn ◽  
David A. Bernlohr ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Adipose Tissue ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Lipocalin 2 ◽  
Wild Type ◽  
Female Mice ◽  
Estrogen Receptor Signaling ◽  
Age Related

We have previously characterized lipocalin 2 (Lcn2) as a new adipokine having a critical role in energy and lipid metabolism in male mice. Previous studies by others have suggested that Lcn2 is a putative target gene of estrogens. In this study, we reported the effect of Lcn2 deficiency on estradiol biosynthesis and estrogen receptor signaling in female Lcn2-deficient (Lcn2−/−) mice. We found that Lcn2 expression in white adipose tissue is gender, depot, and age dependent. In female mice, Lcn2 is predominantly expressed in inguinal adipose tissue but at relatively very low levels in perigonadal depot and ovary. After 22 wk of high-fat diet (HFD) feeding or at old age, Lcn2−/− female mice had significantly reduced levels of serum 17β-estradiol and down-regulated expression of estrogen receptor α in multiple metabolic tissues. Consistently, the expression of estrogen-regulated genes involved in cholesterol homeostasis, such as liver X receptor β and low-density lipoprotein receptor was also down-regulated in the adipose tissue of Lcn2−/− mice. These changes were in line with the development of atherogenic dyslipidemia in response to HFD feeding; female Lcn2−/− mice had significantly elevated levels of total cholesterol and low-density lipoprotein cholesterol, whereas reduced high-density lipoprotein cholesterol levels compared with wild-type female mice. Interestingly, when compared with wild-type controls, HFD-fed female Lcn2−/− mice had significantly reduced expression levels of aromatase, a key enzyme regulating estradiol biosynthesis, in adipose tissue. Moreover, Lcn2 deficiency markedly blunted age-related increase in adipose aromatase expression but had no significant impact on age-related reduction in ovarian aromatase expression. Our findings suggest that Lcn2 has a tissue-specific role in adipose estradiol biosynthesis, which may link Lcn2 to obesity- and age-related estradiol production and metabolic complications in females.

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