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Dai L, Li S, Hao Q, Zhou R, Zhou H, Lei W, Kang H, Wu H, Li Y, Ma X. Low-density lipoprotein: a versatile nanoscale platform for targeted delivery. NANOSCALE ADVANCES 2023; 5:1011-1022. [PMID: 36798503 PMCID: PMC9926902 DOI: 10.1039/d2na00883a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Low-density lipoprotein (LDL) is a small lipoprotein that plays a vital role in controlling lipid metabolism. LDL has a delicate nanostructure with unique physicochemical properties: superior payload capacity, long residence time in circulation, excellent biocompatibility, smaller size, and natural targeting. In recent decades, the superiority and feasibility of LDL particles as targeted delivery carriers have attracted much attention. In this review, we introduce the structure, composition, advantages, defects, and reconstruction of LDL delivery systems, summarize their research status and progress in targeted diagnosis and therapy, and finally look forward to the clinical application of LDL as an effective delivery vehicle.
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Affiliation(s)
- Luyao Dai
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Shuaijun Li
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Qian Hao
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Ruina Zhou
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Hui Zhou
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Wenxi Lei
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Huafeng Kang
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
| | - Hao Wu
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
- Department of Biochemistry and Molecular Medicine, UC Davis Comprehensive Cancer Center, University of California Davis Sacramento CA 95817 USA
- Department of Biophysics, School of Basic Medical Sciences, Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 China
| | - Yuanpei Li
- Department of Biochemistry and Molecular Medicine, UC Davis Comprehensive Cancer Center, University of California Davis Sacramento CA 95817 USA
| | - Xiaobin Ma
- Department of Oncology, The Second Affiliated Hospital, Medical School of Xi'an Jiaotong University Xi'an Shaanxi 710061 China
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Gnanaguru G, Choi AR, Amarnani D, D'Amore PA. Oxidized Lipoprotein Uptake Through the CD36 Receptor Activates the NLRP3 Inflammasome in Human Retinal Pigment Epithelial Cells. Invest Ophthalmol Vis Sci 2017; 57:4704-12. [PMID: 27607416 PMCID: PMC5024668 DOI: 10.1167/iovs.15-18663] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Purpose Accumulation of oxidized phospholipids/lipoproteins with age is suggested to contribute to the pathogenesis of AMD. We investigated the effect of oxidized LDL (ox-LDL) on human RPE cells. Methods Primary human fetal RPE (hf-RPE) and ARPE-19 cells were treated with different doses of LDL or ox-LDL. Assessment of cell death was measured by lactate dehydrogenase release into the conditioned media. Barrier function of RPE was assayed by measuring transepithelial resistance. Lysosomal accumulation of ox-LDL was determined by immunostaining. Expression of CD36 was determined by RT-PCR; protein blot and function was examined by receptor blocking. NLRP3 inflammasome activation was assessed by RT-PCR, protein blot, caspase-1 fluorescent probe assay, and inhibitor assays. Results Treatment with ox-LDL, but not LDL, for 48 hours caused significant increase in hf-RPE and ARPE-19 (P < 0.001) cell death. Oxidized LDL treatment of hf-RPE cells resulted in a significant decrease in transepithelial resistance (P < 0.001 at 24 hours and P < 0.01 at 48 hours) relative to LDL-treated and control cells. Internalized ox-LDL was targeted to RPE lysosomes. Uptake of ox-LDL but not LDL significantly increased CD36 protein and mRNA levels by more than 2-fold. Reverse transcription PCR, protein blot, and caspase-1 fluorescent probe assay revealed that ox-LDL treatment induced NLRP3 inflammasome when compared with LDL treatment and control. Inhibition of NLRP3 activation using 10 μM isoliquiritigenin significantly (P < 0.001) inhibited ox-LDL induced cytotoxicity. Conclusions These data are consistent with the concept that ox-LDL play a role in the pathogenesis of AMD by NLRP3 inflammasome activation. Suppression of NLRP3 inflammasome activation could attenuate RPE degeneration and AMD progression.
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Affiliation(s)
- Gopalan Gnanaguru
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Boston, Massachusetts, United States 2Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Ariel R Choi
- Program in Liberal Medical Education, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States
| | - Dhanesh Amarnani
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Boston, Massachusetts, United States 2Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Patricia A D'Amore
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Boston, Massachusetts, United States 2Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States 4Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States
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Ru D, Zhiqing H, Lin Z, Feng W, Feng Z, Jiayou Z, Yusheng R, Min F, Chun L, Zonggui W. Oxidized high-density lipoprotein accelerates atherosclerosis progression by inducing the imbalance between treg and teff in LDLR knockout mice. APMIS 2015; 123:410-21. [PMID: 25912129 DOI: 10.1111/apm.12362] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 12/01/2014] [Indexed: 01/21/2023]
Abstract
High density lipoprotein (HDL) dysfunction has been widely reported in clinic, and oxidation of HDL (ox-HDL) was shown to be one of the most common modifications in vivo and participate in the progression of atherosclerosis. But the behind mechanisms are still elusive. In this study, we firstly analyzed and found strong relationship between serum ox-HDL levels and risk factors of coronary artery diseases in clinic, then the effects of ox-HDL in initiation and progression of atherosclerosis in LDLR knockout mice were investigated by infusion of ox-HDL dissolved in chitosan hydrogel before the formation of lesions in vivo. Several new evidence were shown: (i) the serum levels of ox-HDL peaked early before the formation of lesions in LDLR mice fed with high fat diet similar to oxidative low density lipoprotein, (ii) the formation of atherosclerotic lesions could be accelerated by infusion of ox-HDL, (iii) the pro-atherosclerotic effects of ox-HDL were accompanied by imbalanced levels of effector and regulatory T cells and relative gene expressions, which implied that imbalance of teff and treg might contribute to the pro-atherosclerosis effects of ox-HDL.
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Affiliation(s)
- Ding Ru
- Department of Cardiology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
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Marin MT, Dasari PS, Tryggestad JB, Aston CE, Teague AM, Short KR. Oxidized HDL and LDL in adolescents with type 2 diabetes compared to normal weight and obese peers. J Diabetes Complications 2015; 29:679-85. [PMID: 25881918 PMCID: PMC9549762 DOI: 10.1016/j.jdiacomp.2015.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/16/2015] [Accepted: 03/05/2015] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Obesity and type 2 diabetes mellitus (T2DM) are associated with oxidative stress. Oxidative damage of high-density lipoprotein (oxHDL) leads to a dysfunctional molecule, potentially a mediator and/or marker of cardiometabolic disease. We tested the hypothesis that circulating concentration of oxHDL is higher in obese (Ob) or T2DM adolescents compared to normal-weight (NW) peers. METHODS In 37 NW, 38 Ob, and 42 T2DM adolescents, ages 11-18 y, fasting concentrations of HDL and LDL cholesterol, oxHDL, oxidized low-density lipoprotein (oxLDL), and myeloperoxidase (MPO) were measured. RESULTS Compared to the NW group, oxHDL in the Ob group was not different, but was 65% higher (p < 0.01) in the T2DM group. Within the T2DM group oxHDL was higher in boys than in girls, but this sex difference was not evident in NW or Ob groups. OxLDL was 23% higher in Ob (p = 0.02), and 56% higher in T2DM (p < 0.01) versus NW and did not differ between boys and girls. MPO was not different between NW and Ob but was 88% (p < 0.02) higher in T2DM compared to NW. Contrary to our hypothesis MPO and insulin resistance (HOMA-IR) were not correlated with oxHDL. OxHDL was positively associated with oxLDL and lean body mass while oxLDL was positively associated with apolipoprotein B, triglycerides, HOMA-IR and trunk fat. CONCLUSIONS The higher concentrations of oxHDL and oxLDL, along with higher MPO in children with T2DM reflect higher oxidative stress compared with obesity alone and potentially increased cardiovascular disease risk in youth with T2DM.
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Affiliation(s)
- Monica T Marin
- Pediatrics, Section of Diabetes/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Paul S Dasari
- Pediatrics, Section of Diabetes/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Jeanie B Tryggestad
- Pediatrics, Section of Diabetes/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Christopher E Aston
- Pediatrics, Biomedical and Behavioral Methodology Core, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - April M Teague
- Pediatrics, Section of Diabetes/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Kevin R Short
- Pediatrics, Section of Diabetes/Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
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Harisa GI, Alanazi FK. Low density lipoprotein bionanoparticles: From cholesterol transport to delivery of anti-cancer drugs. Saudi Pharm J 2013; 22:504-15. [PMID: 25561862 PMCID: PMC4281595 DOI: 10.1016/j.jsps.2013.12.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 12/14/2013] [Indexed: 11/19/2022] Open
Abstract
In this review article, we highlight the importance of low-density lipoprotein (LDL) and its implications in the field of drug delivery to cancer cells. LDL is naturally occurring bionanoparticles (BNP) with a size of 18–25 nm. These BNPs specifically transport cholesterol to cells expressing the LDL receptors (LDLRs). Several tumors overexpress LDLRs, presumably to provide cholesterol for sustaining a high rate of membrane synthesis. LDL BNPs are biocompatible and biodegradable, favorably bind hydrophobic and amphiphilic drugs, are taken up by a receptor-mediated mechanism, have a half-life of 2–4 days, and can be rerouted. Drugs can be loaded onto LDL BNPs by surface loading, core loading, and apoprotein interaction. LDL may be used as a drug carrier for treatment of atherosclerosis, cancer, and in photodynamic therapies.
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Affiliation(s)
- Gamaleldin I Harisa
- Kayyali Chair for Pharmaceutical Industry, Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia ; Department of Biochemistry, College of Pharmacy, Al-Azhar University (Boys), Nasr City, Cairo, Egypt
| | - Fars K Alanazi
- Kayyali Chair for Pharmaceutical Industry, Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia
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Hackett MJ, Zaro JL, Shen WC, Guley PC, Cho MJ. Fatty acids as therapeutic auxiliaries for oral and parenteral formulations. Adv Drug Deliv Rev 2013; 65:1331-9. [PMID: 22921839 DOI: 10.1016/j.addr.2012.07.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 06/25/2012] [Accepted: 07/20/2012] [Indexed: 01/08/2023]
Abstract
Many drugs have decreased therapeutic activity due to issues with absorption, distribution, metabolism and excretion. The co-formulation or covalent attachment of drugs with fatty acids has demonstrated some capacity to overcome these issues by improving intestinal permeability, slowing clearance and binding serum proteins for selective tissue uptake and metabolism. For orally administered drugs, albeit at low level of availability, the presence of fatty acids and triglycerides in the intestinal lumen may promote intestinal uptake of small hydrophilic molecules. Small lipophilic drugs or acylated hydrophilic drugs also show increased lymphatic uptake and enhanced passive diffusional uptake. Fatty acid conjugation of small and large proteins or peptides has exhibited protracted plasma half-lives, site-specific delivery and sustained release upon parenteral administration. These improvements are most likely due to associations with lipid-binding serum proteins, namely albumin, LDL and HDL. These molecular interactions, although not fully characterized, could provide the ability of using the endogenous carrier systems for improving therapeutic outcomes.
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Affiliation(s)
- Michael J Hackett
- University of North Carolina, Chapel Hill, School of Pharmacy, Division of Molecular Pharmaceutics, USA
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Diet and age interactions with regards to cholesterol regulation and brain pathogenesis. Curr Gerontol Geriatr Res 2010:219683. [PMID: 20396385 PMCID: PMC2852598 DOI: 10.1155/2010/219683] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 02/15/2010] [Indexed: 01/10/2023] Open
Abstract
Cholesterol is an essential molecule for brain homeostasis; yet, hypercholesterolemia and its numerous complications are believed to play a role in promoting multiple aspects of brain pathogenesis. An ever increasing number of individuals in modern Western Society are regularly consuming diets high in fat which promote the development of hypercholesterolemia. Additionally, modern societies are becoming increasingly aged, causing a collision between increased hypercholesterolemia and increased aging, which will likely lead to the development of increased pathological conditions due to hypercholesterolemia, thereby promoting deleterious neurochemical and behavioral changes in the brain. Lastly, while beneficial in controlling cholesterol levels, the long-term use of statins itself may potentially promote adverse effects on brain homeostasis, although specifics on this remain largely unknown. This review will focus on linking the current understanding of diet-induced hypercholesterolemia (as well as statin use) to the development of oxidative stress, neurochemical alterations, and cognitive disturbances in the aging brain.
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Curcio CA, Johnson M, Huang JD, Rudolf M. Aging, age-related macular degeneration, and the response-to-retention of apolipoprotein B-containing lipoproteins. Prog Retin Eye Res 2009; 28:393-422. [PMID: 19698799 PMCID: PMC4319375 DOI: 10.1016/j.preteyeres.2009.08.001] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The largest risk factor for age-related macular degeneration (ARMD) is advanced age. A prominent age-related change in the human retina is the accumulation of histochemically detectable neutral lipid in normal Bruch's membrane (BrM) throughout adulthood. This change has the potential to have a major impact on physiology of the retinal pigment epithelium (RPE). It occurs in the same compartment as drusen and basal linear deposit, the pathognomonic extracellular, lipid-containing lesions of ARMD. Here we present evidence from light microscopic histochemistry, ultrastructure, lipid profiling of tissues and isolated lipoproteins, and gene expression analysis that this deposition can be accounted for by esterified cholesterol-rich, apolipoprotein B-containing lipoprotein particles constitutively produced by the RPE. This work collectively allows ARMD lesion formation and its aftermath to be conceptualized as a response to the retention of a sub-endothelial apolipoprotein B lipoprotein, similar to a widely accepted model of atherosclerotic coronary artery disease (CAD) (Tabas et al., 2007). This approach provides a wide knowledge base and sophisticated clinical armamentarium that can be readily exploited for the development of new model systems and the future benefit of ARMD patients.
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Affiliation(s)
- Christine A Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL 35294-0009, USA.
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Plourde NM, Kortagere S, Welsh W, Moghe PV. Structure-activity relations of nanolipoblockers with the atherogenic domain of human macrophage scavenger receptor A. Biomacromolecules 2009; 10:1381-91. [PMID: 19405544 DOI: 10.1021/bm8014522] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxidized low density lipoprotein (oxLDL) uptake by macrophages is mediated by scavenger receptors and leads to unregulated cholesterol accumulation. Micellar nanolipoblockers (NLBs) consist of alkyl chains and polyethylene glycol on mucic acid. NLBs functionalized with anionic groups inhibit oxLDL uptake via the scavenger receptor A (SR-A). Molecular modeling and docking approaches were used to understand the structure-activity relationship (SAR) between NLBs and SR-A. Six NLB models were docked to the SR-A homology model to investigate charge placement and clustering. NLB models with the most favorable binding energy were also the most effective oxLDL inhibitors in THP-1 macrophages. Mutant SR-A models were generated by replacing charged residues with alanine. All charged residues in the region were necessary, with Lys60, Lys63, and Lys66 having the greatest effect on binding. We hypothesize that structural studies aided by theoretical modeling and docking can be used to design promising NLB candidates with optimal binding properties.
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Affiliation(s)
- Nicole M Plourde
- Departments of Chemical and Biochemical Engineering and Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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Ahmed KA, Muniandy S, Ismail IS. N(epsilon)-(Carboxymethyl)lysine and Coronary Atherosclerosis-Associated Low Density Lipoprotein Abnormalities in Type 2 Diabetes: Current Status. J Clin Biochem Nutr 2009; 44:14-27. [PMID: 19177184 PMCID: PMC2613495 DOI: 10.3164/jcbn.08-190] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 09/10/2008] [Indexed: 12/16/2022] Open
Abstract
In comparison to the general population, individuals with diabetes suffer a 3- to 4-fold increased risk for developing complications of atherosclerosis and vascular insufficiency. This fact should be taken into account to develop a suitable determinant for the early detection of these complications and subsequently reduce the adverse effect of type 2 diabetes. In vitro experiments have shown that the products of glucose auto-oxidation and Amadori adducts are both potential sources of N(epsilon)-(carboxymethyl)lysine (CML). Excessive formation of CML on low density lipoprotein (LDL) has been proposed to be an important mechanism for the dyslipidemia and accelerated atherogenesis observed in patients with type 2 diabetes. It has been postulated that the uptake of CML-LDL by LDL receptors is impaired, thereby decreasing its clearance from the blood circulation. Alternatively, the uptake of these modified LDL particles by scavenger receptors on macrophages and vascular smooth muscle cells (SMCs) and by AGE receptors on endothelial cells, SMCs, and monocytes is highly enhanced and this, in turn, is centrally positioned to contribute to the pathogenesis of diabetic vascular complications especially coronary artery disease. The present review summarizes the up-to-date information on effects and mechanism of type 2 diabetes-associated coronary atherosclerosis induced by CML-LDL modification.
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Affiliation(s)
- Khaled A. Ahmed
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Sekaran Muniandy
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Ikram S. Ismail
- Department of Medicine, University of Malaya Medical Center, University of Malaya, 50603 Kuala Lumpur, Malaysia
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Huang JD, Presley JB, Chimento MF, Curcio CA, Johnson M. Age-related changes in human macular Bruch's membrane as seen by quick-freeze/deep-etch. Exp Eye Res 2007; 85:202-18. [PMID: 17586493 PMCID: PMC2352152 DOI: 10.1016/j.exer.2007.03.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 03/22/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Lipid-containing inclusions have been observed in human Bruch's membrane (BrM) and are postulated to be associated with age-related maculopathy (ARM), a major cause of legal blindness in developed countries. The dehydration associated with specimen preparation for thin-section transmission electron microscopy causes loss of these inclusions. Better preservation of the ultrastructure of the inclusions and tissue is achieved by using a quick-freeze/deep-etch preparation. We use this technique to examine normal human macular BrM in order to characterize the deposition of the lipid-rich inclusions and their age-related accumulation within different layers of the tissue. We find that various inclusions mentioned in other studies can be formed by combinations of three basic structures: lipoprotein-like particles (LLPs), small granules (SGs) and membrane-like structures. These inclusions are associated with collagen and elastic fibrils by fine filaments. In younger eyes, these inclusions are found mostly in the elastic (EL) and outer collageneous layer (OCL) and occupy a small fraction of the interfibrillar spacing. As age increases, LLPs and SGs gradually fill the interfibrillar spacing of the EL and inner collageneous layer (ICL) of the tissue, and later form a new sublayer, the lipid wall, within the boundary region between the basal lamina of retinal pigment epithelium (RPE) and ICL. Because the formation of the lipid wall only occurs after these inclusions fill the ICL, and it seems unlikely that the LLPs can pass through the packed layer, this result suggests a possible RPE origin of the LLPs that make up the lipid wall.
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Affiliation(s)
- Jiahn-Dar Huang
- Department of Biomedical Engineering, Northwestern University, Evanston IL USA
| | - J. Brett Presley
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham AL USA
| | - Melissa F. Chimento
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham AL USA
| | - Christine A. Curcio
- Department of Ophthalmology, University of Alabama School of Medicine, Birmingham AL USA
| | - Mark Johnson
- Department of Biomedical Engineering, Northwestern University, Evanston IL USA
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Chnari E, Nikitczuk JS, Wang J, Uhrich KE, Moghe PV. Engineered polymeric nanoparticles for receptor-targeted blockage of oxidized low density lipoprotein uptake and atherogenesis in macrophages. Biomacromolecules 2006; 7:1796-805. [PMID: 16768400 DOI: 10.1021/bm0600872] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Strategies to prevent the uptake of modified low density lipoproteins (LDLs) by immune cells, a major trigger of inflammation and atherogenesis, are challenged by complex interfacial factors governing LDL receptor-mediated uptake. We examine a new approach based on a family of "nanoblockers", which are designed to examine the role of size, charge presentation, and architecture on inhibition of highly oxidized LDL (hoxLDL) uptake in macrophages. The nanoblockers are macromolecules containing mucic acid, lauryl chloride, and poly(ethylene glycol) that self-assemble into 15-20 nm nanoparticles. We report that the micellar configuration of the macromolecules and the combined display of anionic (carboxylate) groups in the hydrophobic region of the nanoblockers caused the most effective inhibition in the uptake of hoxLDL by IC21 macrophages. The nanoblockers primarily targeted SR-A and CD36, the major scavenger receptors and modulated the "atherogenic" phenotype of cells in terms of the degree of cytokine secretion, accumulation of cholesterol, and "foam cell" formation. These studies highlight the promise of synthetically engineered nanoblockers against oxidized LDL uptake.
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Affiliation(s)
- Evangelia Chnari
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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Kerenyi L, Mihalka L, Csiba L, Bacso H, Bereczki D. Role of hyperlipidemia in atherosclerotic plaque formation in the internal carotid artery. JOURNAL OF CLINICAL ULTRASOUND : JCU 2006; 34:283-8. [PMID: 16788960 DOI: 10.1002/jcu.20233] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
PURPOSE The role of hyperlipidemia in atherosclerotic changes of the carotid artery is controversial. The aims of this retrospective study were to assess (1) the relationship between total serum cholesterol and triglyceride and the grade of internal carotid artery stenosis and (2) whether total serum cholesterol and triglyceride levels are independent risk factors for internal carotid artery atherosclerosis. METHODS The files of 1,934 acute ischemic stroke patients were investigated retrospectively. The atherosclerotic involvement of the internal carotid artery was assessed via duplex sonography as percent of stenosis and was graded as follows: group 1, no plaque; group 2, <30% stenosis; group 3, 30-99% stenosis; and group 4, occlusion. RESULTS The mean age of the patients was 66.9 +/- 12.8 years. Patients without any plaque had significantly lower cholesterol levels compared with those with any degree of internal carotid artery stenosis. Univariate analysis revealed that age (p < 0.001), sex (p < 0.001), hypertension (p < 0.05), cholesterol (p < 0.01), triglycerides(p < 0.05), and smoking (p < 0.001) were significant contributors to atherosclerosis. In the ordinal logistic regression model, age (p < 0.001), sex (p < 0.001), smoking(p < 0.001), and cholesterol (p < 0.05) remained independent predictors of internal carotid artery atherosclerosis. CONCLUSIONS Total serum cholesterol level seems to be an independent risk factor of atherosclerosis in the carotid artery.
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Affiliation(s)
- Levente Kerenyi
- Department of Neurology, University of Debrecen, Medical and Health Science Center, Hungary
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Chnari E, Nikitczuk JS, Uhrich KE, Moghe PV. Nanoscale Anionic Macromolecules Can Inhibit Cellular Uptake of Differentially Oxidized LDL. Biomacromolecules 2006; 7:597-603. [PMID: 16471936 DOI: 10.1021/bm0506905] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanoscale particles could be synthetically designed to potentially intervene in lipoprotein matrix retention and lipoprotein uptake in cells, processes central to atherosclerosis. We recently reported on lipoprotein interactions of nanoscale micelles self-assembled from amphiphilic scorpion-like macromolecules based on a lauryl chloride-mucic acid hydrophobic backbone and poly(ethylene glycol) shell. These micelles can be engineered to present varying levels of anionic chemistry, a key mechanism to induce differential retentivity of low-density lipoproteins (LDL) (Chnari, E.; Lari, H. B.; Tian, L.; Uhrich, K. E.; Moghe, P. V. Biomaterials 2005, 26, 3749). In this study, we examined the cellular interactions and the ability of carboxylate-terminated nanoparticles to modulate cellular uptake of differentially oxidized LDL. The nanoparticles were found to be highly biocompatible with cultured IC21 macrophages at all concentrations examined. When the nanoparticles as well as LDL were incubated with the cells over 24 h, a marked reduction in cellular uptake of LDL was observed in a nanoparticle concentration-dependent manner. Intermediate concentrations of nanoparticles (10(-6) M) elicited the most charge-specific reduction in uptake, as indicated by the difference in uptake due to anionic and uncharged nanoparticles. At these concentrations, anionic nanoparticles reduced LDL uptake for all degrees of oxidation (no oxidation, mild, high) of LDL, albeit with qualitative differences in the effects. The anionic nanoparticles were particularly effective at reducing the very high levels of uptake of the most oxidized level of LDL. Since complexation of LDL with anionic nanoparticles is reduced at higher degrees of LDL oxidation, our results suggest that anionic nanoparticles interfere in highly oxidized (hox) LDL uptake, likely by targeting cellular/receptor uptake mechanism, but control unoxidized LDL uptake by mechanisms related to direct LDL-nanoparticle complexation. Thus, anionically functionalized nanoparticles can modulate the otherwise unregulated internalization of differentially oxidized LDL.
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Affiliation(s)
- Evangelia Chnari
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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Chnari E, Lari HB, Tian L, Uhrich KE, Moghe PV. Nanoscale anionic macromolecules for selective retention of low-density lipoproteins. Biomaterials 2005; 26:3749-58. [PMID: 15621265 DOI: 10.1016/j.biomaterials.2004.09.038] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2004] [Accepted: 09/20/2004] [Indexed: 11/27/2022]
Abstract
Synthetically designed anionic nanocarriers that mimic the charge properties of glycosaminoglycans can potentially sequester low-density lipoproteins (LDL) during the treatment of atherosclerosis. In this study, we explore the LDL retentivity of 15-20 nm anionic micelles formed from amphiphilic scorpion-like macromolecules (AScMs) as building blocks. The macromolecules comprise four aliphatic chains attached to mucic acid and a linear polyethylene glycol (PEG) segment to form micellar nanocarriers with a hydrophobic core and hydrophilic corona. Dynamic light scattering and transmission electron microscopy studies indicate that the carboxylate-terminated nanocarriers (20 nm) sequester LDL (22 nm), resulting in complexes with a diameter of 60-90 nm, but neutral ethoxy-terminated nanocarriers do not retain LDL. Further, carboxylate-terminated nanocarriers consistently bound to unoxidized LDL (Relative Electrophoretic Mobility, REM=1.0) and mildly oxidized LDL (REM=1.5), but not highly oxidized LDL (REM=3.6), whereas the neutral nanocarriers displayed no preference/affinity at all, indicating that the nanocarrier-LDL binding is charge-dependent. The binding affinity of unoxidized LDL for differentially charged nanocarriers, formed from varying ratios of carboxylate- and ethoxy-terminated macromolecules, was quantified. The 100% carboxylated nanocarriers elicited the highest binding affinity (K(d)=567 nm), whereas mixed micelles elicited significantly lower levels of binding affinity. Our results highlight the promise of synthetically designed nanomaterials in lipoprotein retention, a key step in managing the escalation of atherosclerosis.
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Affiliation(s)
- Evangelia Chnari
- Department of Chemical and Biochemical Engineering, Rutgers University, 98 Brett Road, C230 Engineering, Piscataway, NJ 08854, USA
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Abstract
Low-density lipoprotein (LDL) cholesterol is an established risk factor for coronary heart disease (CHD). In the presence of oxidative stress LDL particles can become oxidized to form a lipoprotein species that is particularly atherogenic. Indeed, oxidized LDL (oxLDL) is pro-inflammatory, it can cause endothelial dysfunction and it readily accumulates within the arterial wall. Several factors may influence the susceptibility of LDL to oxidation, including its size and composition, and the presence of endogenous antioxidant compounds, such as alpha-tocopherol. Individuals with type 2 diabetes or the metabolic syndrome have high levels of oxidative stress and consequently are at an increased risk for cardiovascular events. Reducing oxidative stress has been proposed as a potential approach to prevent CHD and antioxidant vitamins have been employed with encouraging results in experimental models of atherosclerosis. However, clinical trials have not demonstrated consistent beneficial effects of antioxidants on cardiovascular outcomes. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are the first-line choice for lowering total and LDL cholesterol levels and they have been proven to reduce the risk of CHD. Recent data suggest that these compounds, in addition to their lipid-lowering ability, can also reduce the production of reactive oxygen species and increase the resistance of LDL to oxidation. It may be that the ability of statins to limit the oxidation of LDL contributes to their effectiveness at preventing atherosclerotic disease.
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Affiliation(s)
- Robert S Rosenson
- Preventive Cardiology Center, Northwestern University, The Feinberg School of Medicine, 201 E. Huron Street, Galter Pavilion, Suite 11-120, Chicago, IL 60611, USA.
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