Explore the vast range of titles available.

Cholesterol is an essential component of animal cells. Different regulatory mechanisms converge to maintain adequate levels of this lipid because both its deficiency and excess are unfavorable. Low cell cholesterol content promotes its synthesis and uptake from circulating lipoproteins. In contrast, its excess induces the efflux to high-density lipoproteins (HDL) and their transport to the liver for excretion, a process known as reverse cholesterol transport. Different studies suggest that an abnormal HDL metabolism hinders female fertility. HDL are the only lipoproteins detected in substantial amounts in follicular fluid (FF), and their size and composition correlate with embryo quality. Oocytes obtain cholesterol from cumulus cells via gap junctions because they cannot synthesize cholesterol de novo and lack HDL receptors. Recent evidence has supported the possibility that FF HDL play a major role in taking up excess unesterified cholesterol (UC) from the oocyte. Indeed, genetically modified mouse models with disruptions in reverse cholesterol transport, some of which show excessive circulating UC levels, exhibit female infertility. Cholesterol accumulation can affect the egg´s viability, as reported in other cell types, and activate the plasma membrane structure and activity of membrane proteins. Indeed, in mice deficient for the HDL receptor Scavenger Class B Type I (SR-B1), excess circulating HDL cholesterol and UC accumulation in oocytes impairs meiosis arrest and hinders the developmental capacity of the egg. In other cells, the addition of cholesterol activates calcium channels and dysregulates cell death/survival signaling pathways, suggesting that these mechanisms may link altered HDL cholesterol metabolism and infertility. Although cholesterol, and lipids in general, are usually not evaluated in infertile patients, one study reported high circulating UC levels in women showing longer time to pregnancy as an outcome of fertility. Based on the evidence described above, we propose the existence of a well-regulated and largely unexplored system of cholesterol homeostasis controlling traffic between FF HDL and oocytes, with significant implications for female fertility.

Background Niemann-Pick disease type C1 (NPC1) is caused by NPC1 gene mutations, resulting in Purkinje cell degeneration and death, glial cell activation, and progressive neurodegeneration. Menstrual blood-derived endometrial stem cells (MenSCs) have been explored as a promising tool for treating neurodegenerative diseases due to their wide range of sources, non-invasive nature, and regular collection methods. Objectives This study aims to investigate whether MenSCs can improve neuroinflammation and apoptosis in NPC1 mutant cell ( Npc1 KO BV2 cell line) and mice ( Npc1 −/− mice), and explore their underlying mechanisms. Methods MenSCs were transplanted into the 4-week-old Npc1 −/− mice cerebellum through stereotaxic injection, and their effects on weight, behavior, and survival were assessed. The activation of glial cells and the survival of neurons were detected by immunofluorescence technology, and the expression level of related inflammatory factors and apoptotic proteins was detected by western blotting. The transcriptome changes in cerebellum after MenSCs transplantation were analyzed by transcriptome sequencing. The mechanism by which MenSCs treat NPC1 was validated at the cellular level using the activator butyzamide. Results MenSCs transplantation could slow down the rate of weight loss and improve motor coordination in Npc1 −/− mice, but had no significant improvement in lifespan. MenSCs could mitigate the activation of glial cells, alleviate neuroinflammation, reduce cell apoptosis, and increase the number of mature neurons and Purkinje cells in the cerebellum. Transcriptome analyses results indicated that the JAK/STAT signaling pathway changed across different groups. Compared with age-matched Npc1 +/+ mice, the protein expression levels of P-JAK2 and P-STAT3, the ratios of P-JAK2/JAK2 and P-STAT3/STAT3 were increased in the cerebellum of 5-week-old Npc1 −/− mice in the PBS group; compared with age-matched Npc1 −/− mice in the PBS group, the protein expression levels of P-JAK2 and P-STAT3, the ratios of P-JAK2/JAK2 and P-STAT3/STAT3 were decreased after MenSCs transplantation. Finally, treating Npc1 KO BV2 cells with butyzamide further confirmed that MenSCs relieve inflammation and apoptosis caused by Npc1 gene mutations through JAK2/STAT3 signaling pathway. Conclusion Our study demonstrate that MenSCs ameliorate neuroinflammation and apoptosis in NPC1 mutant cell and mice through JAK2/STAT3 signaling pathway.

Statins, 3‐hydroxyl‐3‐methylglutaryl coenzyme A reductase inhibitors, are the first‐line medications prescribed for the prevention and treatment of coronary artery diseases. The efficacy of statins has been attributed not only to their systemic cholesterol‐lowering actions but also to their pleiotropic effects that are unrelated to cholesterol reduction. These pleiotropic effects have been increasingly recognized as essential in statins therapy. This study was designed to investigate the pleiotropic actions of simvastatin, one of the most commonly prescribed statins, on macrophage cholesterol homeostasis with a focus on lysosomal free cholesterol egression. With simultaneous nile red and filipin staining, analysis of confocal/multi‐photon imaging demonstrated that simvastatin markedly attenuated unesterified (free) cholesterol buildup in macrophages loaded with oxidized low‐density lipoprotein but had little effect in reducing the sizes of cholesteryl ester‐containing lipid droplets; the reduction in free cholesterol was mainly attributed to decreases in lysosome‐compartmentalized cholesterol. Functionally, the egression of free cholesterol from lysosomes attenuated pro‐inflammatory cytokine secretion. It was determined that the reduction of lysosomal free cholesterol buildup by simvastatin was due to the up‐regulation of Niemann‐Pick C1 (NPC1), a lysosomal residing cholesterol transporter. Moreover, the enhanced enzymatic production of 7‐hydroxycholesterol by cytochrome P450 7A1 and the subsequent activation of liver X receptor α underscored the up‐regulation of NPC1. These findings reveal a novel pleiotropic effect of simvastatin in affecting lysosomal cholesterol efflux in macrophages and the associated significance in the treatment of atherosclerosis.

Niemann-Pick disease type C (NPC) is a lethal neurologic storage disorder of children most often caused by a defect in the protein NPC1. To better understand the disease we thoroughly characterized the cellular and morphological alterations occurring in murine, feline, and human NPC. Using immunocytochemistry and filipin histochemistry we show that both gangliosides and unesterified cholesterol are differentially stored in neurons of the cerebral cortex, cerebellum, and hippocampus, as well as in liver. Double fluorescence labeling revealed that GM2 ganglioside and unesterified cholesterol were partially co-localized in vesicular structures, and triple fluorescence labeling utilizing a LAMP-1 antibody identified many of these organelles as part of the late endosomal/lysosomal pathway. These observations, coupled with the proposed role of NPC1 in intracellular cholesterol movement, suggest that GM3 and GM2 gangliosides as well as unesterified cholesterol may be retrogradely cleared from late endosomes/lysosomes by an NPC1-dependent mechanism. Cellular consequences of the NPC metabolic defect as shown by parvalbumin immunocytochemistry and rapid Golgi staining, respectively, revealed characteristic axonal spheroids on GABAergic neurons and ectopic dendritogenesis that followed a species-specific gradient ofmouse < feline < human. These studies suggest that the homeostatic regulation of gangliosides and cholesterol in neurons is mediated by NPC1 and that perturbations in this mechanism cause a complex neuronal storage disorder.

Mice with homozygous null mutations in the high-density lipoprotein receptor SR-BI (scavenger receptor class B, type I) and apolipoprotein E genes fed a low-fat diet exhibit a constellation of pathologies shared with human atherosclerotic coronary heart disease (CHD): hypercholesterolemia, occlusive coronary atherosclerosis, myocardial infarctions, cardiac dysfunction (heart enlargement, reduced systolic function and ejection fraction, and ECG abnormalities), and premature death (mean age 6 weeks). They also exhibit a block in RBC maturation and abnormally high plasma unesterified-to-total cholesterol ratio (0.8) with associated abnormal lipoprotein morphology (lamellar/vesicular and stacked discoidal particles reminiscent of those in lecithin/cholesterol acyltransferase deficiency and cholestasis). Treatment with the lipid-lowering, antiatherosclerosis, and antioxidation drug probucol extended life to as long as 60 weeks (mean 36 weeks), and at 5-6 weeks of age, virtually completely reversed the cardiac and most RBC pathologies and corrected the unesterified to total cholesterol ratio (0.3) and associated distinctive abnormal lipoprotein morphologies. Manipulation of the timing of administration and withdrawal of probucol could control the onset of death and suggested that critical pathological changes usually occurred in untreated double knockout mice between ≈3 (weaning) and 5 weeks of age and that probucol delayed heart failure even after development of substantial CHD. The ability of probucol treatment to modulate pathophysiology in the double knockout mice enhances the potential of this murine system for analysis of the pathophysiology of CHD and preclinical testing of new approaches for the prevention and treatment of cardiovascular disease.

Aim: To determine if elevated plasma levels of atherogenic and/or anti-atherogenic lipoproteins are risk factors for developing age related maculopathy (ARM). Methods: In a cross sectional study in a university clinic setting, 129 patients (72 women and 57 men) underwent colour fundus photography, acuity and contrast sensitivity assessment, and electroimmunoassays of plasma apolipoproteins B (apoB) and A-I (apoA-I), the principal proteins of low density and high density lipoproteins, respectively. Maculopathy stage was assigned using the AREDS grading system. Results: Levels of apoB in no ARM, mild, intermediate, and advanced ARM groups were 93.3, 91.8, 95.2, and 98.2 mg/dl, respectively. Levels of apoA-I were 147.4, 148.6, 141.0, and 144.9 mg/dl in the same groups. There was no significant association between these measures, typical for age, and maculopathy stage. Conclusion: Although drusen associated with ARM and ageing contain cholesterol and apoB, like the lipid rich core of an atherosclerotic plaque, the results of this study and our previous work in toto make the prospects of a plasma origin for these lesion constituents increasingly untenable. This conclusion is consistent with an emerging hypothesis that a large lipoprotein of intraocular origin is an important pathway for constituent retinal lipid processing and the biogenesis of drusen.

Lipoprotein-X stimulates monocyte chemoattractant protein-1 expression in mesangial cells via nuclear factor-κB. Lipoprotein-X (Lp-X) is an abnormal lipoprotein found in the plasma of patients with familial lecithin:cholesterol acyltransferase (LCAT) deficiency. The majority of patients with this disorder develop progressive glomerulosclerosis. One key event in the pathogenesis of glomerulosclerosis is the infiltration of monocytes into affected glomeruli. Mesangial cells can synthesize and secrete monocyte chemoattractant protein-1 (MCP-1), an important chemoattractant for monocytes. The objective of the present study was to examine the effect of Lp-X on MCP-1 expression in mesangial cells leading to an enhanced monocyte chemotaxis and to elucidate the mechanisms involved in this process. Lp-X was isolated from the plasma of a patient with familial LCAT deficiency. After rat mesangial cells were incubated with Lp-X for four or six hours, the expression of MCP-1 mRNA was determined by nuclease protection assay, and MCP-1 protein was measured by Western immunoblotting analysis. Monocyte chemotaxis was determined by using a Micro Chemotaxis Chamber. Lp-X (50 to 100nmol/mL) stimulated mesangial cell MCP-1 mRNA expression (137 to 220%) and MCP-1 protein levels (233 to 375%). Conditioned media collected from Lp-X–treated mesangial cells stimulated human acute monocytic leukemia (THP-1) monocyte chemotaxis (165 to 200%). The increase in MCP-1 expression in mesangial cells was associated with an elevation of intracellular diacylglycerol levels, and activation of protein kinase C (PKC) as well as nuclear factor-κB (NF-κB). These results suggest that Lp-X participates in the pathogenesis of glomerulosclerosis and subsequent renal failure in familial LCAT deficient patients by stimulating monocyte infiltration via a mechanism involving mesangial MCP-1 expression.

AIM To report the quantitation of the lipid composition of a corneal button from a Japanese woman in her 60s with clinically and histopathologically proved Schnyder’s corneal dystrophy. METHODS Total lipids extracted from the corneal button of the patient were analysed by the method of thin layer chromatography flame ionisation detection. Two different solvent systems were used for neutral lipid analysis and phospholipid analysis. Results were compared with three age matched corneal buttons obtained from cadaveric eyes. RESULTS The lipids that accumulated in the cornea in Schnyder’s dystrophy consisted mainly of unesterified cholesterol and phospholipids. The analysis of phospholipids showed sphingomyelin to be the predominant phospholipid in the patient’s cornea. CONCLUSION Findings suggest that this disorder involves a disturbance of the metabolism of cholesterol and/or sphingomyelin metabolism that is limited to the cornea.

Lipoproteins are large macromolecular complexes that transport hydrophobic lipids in the blood. Lipoproteins consist of a core of hydrophobic lipids (triglycerides (TGs) and cholesteryl esters) surrounded by a shell of hydrophilic lipids (phospholipids and unesterified cholesterol) and proteins. The plasma lipoproteins are divided into five major classes based on their relative density: chylomicrons, very‐low‐density lipoproteins (VLDLs), intermediate‐density lipoproteins (IDLs), low‐density lipoprotein (LDL), and high‐density lipoprotein (HDL). This chapter describes LDL, triglyceride‐rich lipoproteins (TRLs), and HDL, and their relationship to atherosclerosis. Lipoproteins are important risk factors for atherosclerotic cardiovascular disease (CVD). HDL cholesterol (HDL‐C) is a major independent inverse risk factor for coronary heart disease (CHD). LDL cholesterol (LDL‐C), plasma triglyceride (TG), and HDL‐C can all be used to predict risk of CHD, but data currently exist only for intervention targeted toward reducing LDL‐C as a strategy to reduce risk of cardiovascular events.

Background: The hypothesis is proposed that the atherogenicity of lipoporotein fractions is correlated with the content of unesterified cholesterol. Objectives: To evaluate the role and prognostic values of unesterified and esterified cholesterol in lipoprotein fractions for coronary artery disease (CAD). Design and methods: The study population consisted of 400 patients who were divided to CAD controls and cases according to the data of coronary angiography. Fractional cholesterol esterification (FCE) as well as the complete profile of lipids and (apo)lipoproteins were determined. Results: Total cholesterol was increased significantly in CAD patients (196.3 ± 52.3 mg/dL vs. 185.7 ± 48.0, p£ 0.049) and the increment occurred totally in unesterified portion (77.2 ± 28.4 mg/dL vs. 71.1 ± 24.4, p£ 0.031). HDL cholesterol showed a significant decrease in CAD group (39.9 ± 9.5 mg/dL vs. 44.6 ± 10.5, p£ 0.001), but the decrement occurred wholly in the esterified portion (26.2 ± 9.2 mg/dL vs. 31.1 ± 8.1, p£ 0.001). NonHDL cholesterol was increased significantly in CAD group (156.8 ± 48.3 mg/dL vs. 140.3 ± 43.6, p£ 0.001), and the changes occurred in both un- and esterified portions. FCE in HDL was diminished significantly in CAD patients (64.8 ± 13.9% vs. 69.3 ± 7.9, p£ 0.01). In multivariate logistic regression analysis, unesterified cholesterol in NonHDL (UeNonHDLc) and esterified cholesterol in HDL (EsHDLc) excluded total cholesterol and HDLc respectively from the regression equation. In ROC analysis, the ratio of UeNonHDLc/EsHDLc was the strongest predictor for CAD among cholesterol subfractions. Conclusions: The results confirm that UeNonHDLc is atherogenic and EsHDLc is antiatherogenic and are independent risk factors for CAD.