Apolipoproteins in Lipid Metabolism, Atherosclerosis, and Neurometabolic Disease Research
Apolipoproteins in Lipid Metabolism, Atherosclerosis, and Neurometabolic Disease Research
Apolipoproteins (Apos) are important protein components of lipoprotein particles. They participate in the transport of triglycerides, cholesterol, phospholipids, and lipid-soluble molecules, and determine the interactions between lipoproteins and receptors, enzymes, and transport proteins.
Keywords: apolipoprotein; ApoA-I; ApoB; ApoE; ApoC; lipoprotein; reverse cholesterol transport; atherosclerosis; lipid metabolism; neurodegenerative disease
1 Basic Characteristics of Apolipoproteins
1.1 Functional Positioning of Apolipoproteins
Apolipoproteins are not merely structural proteins attached to lipid surfaces; they are functional cores for lipoprotein particle recognition, transport, and metabolism. Lipoprotein particles consist of a hydrophobic lipid core and a hydrophilic surface. Apolipoproteins are located on the particle surface or participate in structural stabilization, allowing lipids to be transported in blood, lymph, and tissue fluid.
(1) Structural stabilization
Apolipoproteins can stabilize the surface of lipoprotein particles and maintain particle morphology and solubility. For example, ApoA-I is an important structural protein of HDL, while ApoB-100 is the core structural protein of VLDL, IDL, and LDL.
(2) Receptor recognition
Some apolipoproteins function as ligands for lipoprotein receptor recognition. ApoB-100 and ApoE mediate uptake related to the LDL receptor family, affecting plasma cholesterol clearance and tissue lipid uptake.
(3) Enzyme regulation
ApoC-II activates lipoprotein lipase (LPL), promoting hydrolysis of triglyceride-rich lipoproteins. ApoC-III inhibits triglyceride clearance and is associated with hypertriglyceridemia and accumulation of remnant lipoproteins.
(4) Transport regulation
ApoA-I cooperates with molecules such as ABCA1, ABCG1, and LCAT to promote reverse cholesterol transport, making it a core molecule in HDL function research.
1.2 Apolipoproteins and Lipoprotein Particles
Lipoprotein particles can be classified by density and composition into chylomicrons, VLDL, IDL, LDL, and HDL. Different particles carry different apolipoproteins, which determine their metabolic fate and biological function.
Figure 1 Basic structure of a lipoprotein particle
Table 1 Major Lipoprotein Particles and Their Apolipoprotein Composition
Lipoprotein Type | Major Lipid Components | Representative Apolipoproteins | Main Function |
Chylomicrons | Exogenous triglycerides | ApoB-48, ApoC-II, ApoC-III, ApoE | Transport dietary lipids absorbed from the intestine |
VLDL | Endogenous triglycerides | ApoB-100, ApoC, ApoE | Transport triglycerides synthesized by the liver |
IDL | Intermediate product of VLDL metabolism | ApoB-100, ApoE | Participates in conversion from VLDL to LDL or hepatic uptake |
LDL | Cholesteryl esters | ApoB-100 | Delivers cholesterol to peripheral tissues and is closely related to atherosclerosis |
HDL | Phospholipids, cholesterol, cholesteryl esters | ApoA-I, ApoA-II, ApoM, ApoE | Reverse cholesterol transport, antioxidant effects, anti-inflammatory effects, and endothelial protection |
2 Major Apolipoprotein Families
2.1 ApoA Family
The ApoA family is mainly associated with HDL function, intestinal lipid absorption, and reverse cholesterol transport.
(1) ApoA-I
ApoA-I interacts with ABCA1 to promote cellular cholesterol and phospholipid efflux and form nascent HDL. LCAT then esterifies free cholesterol, allowing HDL to gradually mature. ApoA-I level and function are commonly used to evaluate reverse cholesterol transport, HDL quality, and cardiovascular protective capacity.
(2) ApoA-II
ApoA-II is also one of the major proteins of HDL and can affect HDL particle structure, lipid composition, and enzyme activity. Its role is context-dependent and should not be simply interpreted as absolutely protective or absolutely pathogenic.
(3) ApoA-IV and ApoA-V
ApoA-IV is mainly related to intestinal lipid absorption, chylomicron formation, and energy metabolism. ApoA-V is closely related to triglyceride metabolism regulation. Both can serve as important indicators in studies of lipid absorption and triglyceride-rich lipoprotein metabolism.
2.2 ApoB Family
ApoB is an important structural protein of cholesterol- or triglyceride-rich lipoproteins and mainly includes ApoB-48 and ApoB-100.
(1) ApoB-48
ApoB-48 is mainly produced by the small intestine and is an essential structural protein for chylomicron formation. Its changes are commonly used to study dietary lipid absorption, intestinal lipoprotein production, and postprandial lipid metabolism.
(2) ApoB-100
ApoB-100 is mainly produced by the liver and is the core structural protein of VLDL, IDL, and LDL. Each LDL particle usually contains one ApoB-100 molecule; therefore, ApoB level can reflect the number of atherogenic lipoprotein particles. Compared with LDL-C alone, ApoB more directly reflects the burden of ApoB-containing lipoprotein particles.
Figure 2 Schematic diagram of ApoB-100 structural distribution in lipoprotein particles
(3) Result interpretation
Elevated ApoB suggests an increased number of atherogenic lipoprotein particles, but interpretation should be combined with LDL-C, non-HDL-C, triglycerides, Lp(a), and inflammatory status.
2.3 ApoC Family
The ApoC family mainly regulates the hydrolysis and clearance of triglyceride-rich lipoproteins. ApoC-II and ApoC-III have clearly different functional directions.
(1) ApoC-II
ApoC-II is an important activator of LPL and promotes triglyceride hydrolysis in chylomicrons and VLDL. ApoC-II deficiency can lead to severe hypertriglyceridemia and chylomicronemia.
(2) ApoC-III
ApoC-III inhibits LPL-mediated triglyceride hydrolysis and affects the clearance of triglyceride-rich remnants. Elevated ApoC-III is associated with hypertriglyceridemia, remnant lipoprotein accumulation, and atherosclerotic risk.
(3) ApoC-I
ApoC-I can affect lipoprotein receptor binding, remnant clearance, and cholesteryl ester transfer-related processes. It has reference value in studies of triglyceride-rich lipoprotein metabolism, inflammation, and lipoprotein particle remodeling.
2.4 ApoE Family
ApoE is a core apolipoprotein in studies of lipoprotein remnant clearance, neural lipid metabolism, and disease risk. ApoE can mediate the binding of triglyceride-rich remnants and some HDL particles to the LDL receptor family, promoting uptake by the liver and tissues.
(1) ApoE isoforms
Human ApoE mainly exists as three common isoforms: E2, E3, and E4. ApoE3 is the most common form. ApoE2 has weaker receptor-binding ability and can be associated with type III hyperlipoproteinemia. ApoE4 is closely associated with Alzheimer’s disease risk and abnormal neural lipid metabolism.
(2) Peripheral lipid metabolism
ApoE participates in the clearance of chylomicron remnants, VLDL remnants, and IDL. ApoE dysfunction can lead to remnant lipoprotein accumulation and promote atherosclerosis.
(3) Central nervous system
In the brain, ApoE is mainly produced by astrocytes, microglia, and neuron-associated cells under certain stress conditions. It participates in cholesterol transport, synaptic repair, Aβ metabolism, neuroinflammation, and blood-brain barrier function.
2.5 ApoD, ApoH, ApoM, ApoL, and Apo(a)
(1) ApoD
ApoD is a lipid-binding protein and is commonly associated with oxidative stress, nervous system injury, lipid transport, and tissue repair.
(2) ApoH
ApoH, also known as β2-glycoprotein I, participates in lipid binding, coagulation, and immune-related responses and is important in antiphospholipid antibody-related research.
(3) ApoM
ApoM is mainly distributed in HDL and can carry sphingosine-1-phosphate (S1P), participating in studies of endothelial barrier function, inflammatory regulation, and vascular protection.
(4) ApoL family
The ApoL family is associated with lipid binding, cell death, immune defense, and kidney disease. Among them, ApoL1 is important in research on genetic risk for kidney disease.
(5) Apo(a)
Apo(a) is linked to ApoB-100 through a disulfide bond to form lipoprotein(a), or Lp(a). Lp(a) has both LDL-like lipid transport features and plasminogen-like structural features and is associated with atherosclerosis and thrombotic risk.
Table 2 Major Apolipoproteins and Research Positioning
Apolipoprotein | Main Distribution | Core Function | Research Focus |
ApoA-I | HDL | HDL structural protein; promotes cholesterol efflux and LCAT activation | Reverse cholesterol transport, HDL function, cardiovascular protection |
ApoA-II | HDL | Regulates HDL structure and enzyme activity | HDL particle heterogeneity, lipid metabolism |
ApoA-IV | Chylomicrons, HDL | Intestinal lipid absorption, energy metabolism | Postprandial lipid metabolism, intestinal lipoproteins |
ApoA-V | VLDL- and HDL-related components | Regulates triglyceride metabolism | Hypertriglyceridemia, LPL-related regulation |
ApoB-48 | Chylomicrons | Intestinal lipoprotein formation | Dietary lipid absorption, postprandial hyperlipidemia |
ApoB-100 | VLDL, IDL, LDL, Lp(a) | Structural protein of ApoB-containing lipoproteins; LDL receptor ligand | Atherosclerosis, LDL particle burden |
ApoC-I | VLDL, HDL | Regulates remnant clearance and lipoprotein remodeling | Triglyceride-rich lipoprotein metabolism |
ApoC-II | Chylomicrons, VLDL, HDL | Activates LPL and promotes triglyceride hydrolysis | Hypertriglyceridemia, LPL function |
ApoC-III | VLDL, chylomicrons, HDL | Inhibits triglyceride clearance and remnant metabolism | Remnant lipoproteins, cardiovascular risk |
ApoD | HDL, neural tissue, and others | Lipid binding and oxidative stress-related regulation | Neural injury, lipid transport, stress response |
ApoE | Remnant lipoproteins, HDL, brain lipoprotein-like particles | Remnant clearance and neural lipid transport | Atherosclerosis, Alzheimer’s disease |
ApoH | Plasma lipoproteins, phospholipid surfaces | Lipid binding, coagulation, and immune response | Antiphospholipid antibodies, thrombosis, immune-related research |
ApoM | HDL | Carries S1P and maintains endothelial function | Vascular barrier, inflammation, HDL function |
ApoL1 | HDL-related components, kidney-related tissues | Immune defense, cell death, and kidney risk | Genetic risk of kidney disease, inflammation, cell injury |
Apo(a) | Lp(a) | Forms lipoprotein(a) | Atherosclerosis, thrombotic risk |
3 Apolipoproteins and Lipid Metabolic Processes
3.1 Exogenous Lipid Transport
After dietary lipids are absorbed in the intestine, chylomicrons are formed. ApoB-48 is the key structural protein required for chylomicron assembly. After entering the circulation, chylomicrons can acquire ApoC-II and ApoE from HDL. ApoC-II activates LPL, allowing triglycerides to be hydrolyzed and used by muscle and adipose tissues. Remnant particles are then taken up by the liver through ApoE-mediated mechanisms.
3.2 Endogenous Lipid Transport
Triglycerides and cholesterol synthesized by the liver are exported through VLDL. VLDL contains ApoB-100 and is converted into IDL and LDL through LPL-mediated hydrolysis in the circulation. LDL is rich in cholesteryl esters and is mainly taken up by cells through binding between ApoB-100 and the LDL receptor. If LDL particle number is excessive or clearance is insufficient, the risk of vascular wall lipid deposition increases.
3.3 Reverse Cholesterol Transport
Reverse cholesterol transport is the core process in HDL function research. ApoA-I and ABCA1 promote cellular cholesterol efflux and form nascent HDL. LCAT esterifies free cholesterol and promotes HDL maturation. Mature HDL can deliver cholesterol to the liver through SR-BI and participate in cholesterol excretion.
Table 3 Lipid Metabolic Processes Involving Apolipoproteins
Metabolic Process | Major Apolipoproteins | Key Process | Common Indicators |
Intestinal lipid absorption | ApoB-48, ApoA-IV | Chylomicron assembly and secretion | ApoB-48, postprandial TG, chylomicron remnants |
Triglyceride hydrolysis | ApoC-II, ApoC-III, ApoA-V | LPL activation or inhibition | TG, LPL activity, ApoC-II, ApoC-III, ApoA-V |
Remnant clearance | ApoE, ApoC-I | Hepatic receptor-mediated uptake | Remnant cholesterol, ApoE, IDL |
LDL metabolism | ApoB-100 | LDL formation and receptor-mediated clearance | ApoB, LDL-C, non-HDL-C |
Reverse cholesterol transport | ApoA-I, ApoM | Cholesterol efflux, HDL maturation, and endothelial protection | HDL-C, ApoA-I, ApoM, cholesterol efflux capacity |
Neural lipid transport | ApoE, ApoD, Clusterin/ApoJ | Cholesterol transport, Aβ processing, neural repair | ApoE, ApoD, Clusterin, Aβ, Tau |
4 Apolipoproteins and Disease Mechanisms
4.1 Atherosclerosis and Cardiovascular Disease
Apolipoproteins are closely related to atherosclerosis. ApoB-containing lipoprotein particles can enter the arterial intima, where they are retained, oxidized, or modified. After uptake by macrophages, foam cells are formed, driving plaque formation. Higher ApoB levels usually indicate a larger number of atherogenic particles.
(1) ApoB and risk assessment
ApoB reflects the total number of ApoB-containing particles, including LDL, VLDL remnants, IDL, and Lp(a). In conditions with elevated triglycerides, metabolic syndrome, or small dense LDL particles, ApoB may better reflect particle burden than LDL-C.
(2) ApoA-I and protective function
ApoA-I participates in reverse cholesterol transport and is usually associated with HDL function. However, increased HDL-C does not necessarily indicate enhanced HDL function. Therefore, ApoA-I, cholesterol efflux capacity, and HDL inflammatory status are more suitable for in-depth mechanistic research.
(3) ApoC-III and remnant metabolism
Elevated ApoC-III can inhibit triglyceride clearance and promote remnant lipoprotein accumulation. Remnant particles are rich in cholesterol and have strong atherogenic potential.
4.2 Hypertriglyceridemia and Metabolic Syndrome
Hypertriglyceridemia is commonly associated with excessive VLDL secretion, insufficient LPL function, elevated ApoC-III, insulin resistance, and enhanced adipose tissue lipolysis. ApoC-II deficiency can cause impaired LPL activation, whereas excessive ApoC-III can inhibit clearance of triglyceride-rich lipoproteins.
(1) Recommended detection
TG, ApoC-II, ApoC-III, LPL activity, ApoB, non-HDL-C, remnant cholesterol, and insulin resistance indicators.
(2) Interpretation focus
Elevated triglycerides should not be interpreted by TG value alone. It is necessary to determine whether the increase results from excessive hepatic VLDL, impaired clearance of intestinal chylomicrons, or remnant lipoprotein accumulation.
4.3 Neurodegenerative Diseases
ApoE is one of the most important apolipoproteins in neurodegenerative disease research. Cholesterol in the brain is mainly synthesized and circulated locally, and ApoE participates in lipid transport among neurons, astrocytes, and microglia.
(1) ApoE and Alzheimer’s disease
ApoE4 is associated with increased Alzheimer’s disease risk and may involve mechanisms such as Aβ aggregation and clearance, Tau pathology, neuroinflammation, synaptic function, and blood-brain barrier injury.
(2) ApoD and Clusterin/ApoJ
ApoD and Clusterin/ApoJ are commonly associated with neural stress, lipid transport, proteostasis, and injury repair. They can serve as auxiliary indicators in studies of neurodegenerative diseases, oxidative stress, and tissue protection.
(3) Interpretation focus
The roles of ApoE in the periphery and central nervous system cannot be directly equated. Plasma ApoE, cerebrospinal fluid ApoE, and brain tissue ApoE expression represent different biological levels and should be interpreted separately.
4.4 Liver Disease and Fatty Liver
The liver is an important source of multiple apolipoproteins, including ApoB-100, ApoE, and ApoC. Fatty liver, insulin resistance, and inflammatory states can alter VLDL secretion, ApoB stability, and lipoprotein remnant metabolism.
(1) Research focus
In nonalcoholic fatty liver disease, increased VLDL secretion and impaired lipid export may coexist. ApoB-100, MTP, TG, and hepatic lipid deposition should be analyzed together.
(2) Interpretation focus
Reduced ApoB does not necessarily indicate reduced risk; it may also suggest impaired hepatic lipoprotein assembly or secretion. Interpretation should be combined with hepatic lipid content, lipid profile, and liver injury indicators.
4.5 Kidney Disease and Inflammatory Immunity
Chronic kidney disease is often accompanied by abnormal lipoprotein metabolism, reduced HDL function, and altered ApoA-I/ApoB balance. ApoL1 genetic variants are associated with the risk of certain kidney diseases, and the ApoM-S1P axis is also related to endothelial barrier function and inflammatory regulation. ApoH can participate in phospholipid binding, coagulation, and immune-related processes and is suitable for research on thrombosis, antiphospholipid antibodies, and inflammation crosstalk.
Table 4 Apolipoprotein-Related Diseases and Research Focuses
Disease or Process | Related Apolipoproteins | Mechanistic Direction | Recommended Detection |
Atherosclerosis | ApoB, ApoA-I, ApoC-III, ApoE, Apo(a) | ApoB-containing particle deposition, reduced HDL function, abnormal remnant clearance | ApoB, ApoA-I, Lp(a), non-HDL-C, remnant cholesterol |
Hypertriglyceridemia | ApoC-II, ApoC-III, ApoA-V, ApoB | LPL regulation, abnormal VLDL/chylomicron clearance | TG, ApoC-II, ApoC-III, LPL activity |
Alzheimer’s disease | ApoE, ApoD, Clusterin/ApoJ | Aβ metabolism, neuroinflammation, blood-brain barrier, and lipid transport | ApoE isoform, Aβ, Tau, glial cell markers |
Fatty liver | ApoB-100, ApoE, ApoC | VLDL secretion, hepatic lipid export, and remnant metabolism | ApoB, TG, hepatic lipids, MTP |
Chronic kidney disease | ApoA-I, ApoB, ApoL1, ApoM | HDL dysfunction, endothelial barrier, and genetic risk | ApoA-I, ApoB, ApoL1, ApoM |
Thrombosis and immune response | ApoH, ApoM, ApoL-related proteins | Phospholipid binding, coagulation regulation, inflammatory response | ApoH, ApoM, inflammation and coagulation-related indicators |
5 Experimental Design and Result Interpretation in Apolipoprotein Research
5.1 Sample Type Selection
Apolipoprotein research can use serum, plasma, cerebrospinal fluid, cell culture supernatant, liver tissue, arterial tissue, brain tissue, kidney tissue, and isolated lipoprotein fractions. Different samples reflect information at different biological levels.
(1) Serum or plasma
These samples are suitable for detecting circulating levels of ApoA-I, ApoB, ApoE, ApoC-III, ApoM, and other apolipoproteins, and are commonly used in metabolic and cardiovascular risk research.
(2) Tissue samples
These samples are suitable for analyzing hepatic lipoprotein synthesis, arterial wall lipid deposition, brain ApoE expression, kidney ApoL1-related changes, and local inflammatory status.
(3) Lipoprotein fractions
After VLDL, LDL, HDL, and other fractions are obtained by ultracentrifugation, size-exclusion chromatography, or immunoisolation, the distribution of apolipoproteins among different lipoprotein fractions can be further studied.
5.2 Detection Indicator Combinations
A single apolipoprotein indicator is usually insufficient to explain complex lipid metabolism. Lipid profiles, lipoprotein particles, enzyme activity, and tissue functional indicators should be combined for comprehensive analysis.
Table 5 Common Detection Indicators in Apolipoprotein Research
Research Purpose | Recommended Indicators | Interpretation Focus |
Assessing atherosclerotic risk | ApoB, ApoA-I, ApoB/ApoA-I, Lp(a), non-HDL-C | ApoB reflects the number of atherogenic particles |
Assessing HDL function | ApoA-I, ApoM, HDL-C, cholesterol efflux capacity, LCAT activity | HDL-C is not equivalent to HDL function |
Assessing triglyceride metabolism | ApoC-II, ApoC-III, ApoA-V, TG, LPL activity | Distinguish insufficient LPL activation from impaired clearance |
Assessing remnant lipoproteins | ApoE, ApoC-I, remnant cholesterol, IDL, VLDL remnants | Remnant accumulation is associated with cardiovascular risk |
Assessing neural lipid metabolism | ApoE isoform, ApoE, ApoD, Clusterin, Aβ, Tau | Peripheral and central results should be interpreted by biological level |
Assessing hepatic lipid export | ApoB-100, MTP, VLDL-TG, hepatic TG | ApoB changes should be interpreted with hepatic lipid deposition |
Assessing kidney and inflammatory risk | ApoL1, ApoM, ApoH, inflammatory indicators | Interpret according to tissue source and disease context |
5.3 Common Experimental Methods
(1) ELISA
ELISA is suitable for quantitative detection of apolipoprotein levels in serum, plasma, cell culture supernatant, or tissue homogenates. It is commonly used to detect ApoA-I, ApoB, ApoE, ApoC, ApoD, ApoH, ApoM, and other indicators.
(2) Western blot
Western blot is suitable for detecting apolipoprotein expression in tissue or cell samples and can distinguish some protein bands, isoforms, or degradation/modification-related forms, but quantitative performance is affected by antibody specificity and sample processing.
(3) Immunohistochemistry and immunofluorescence
These methods are suitable for analyzing apolipoprotein localization in arterial plaques, liver, brain tissue, or kidney, especially for colocalization studies of ApoE, ApoB, ApoA-I, ApoL1, and cell type markers.
(4) Lipoprotein separation
Ultracentrifugation, FPLC, or size-exclusion chromatography can separate VLDL, LDL, and HDL particles for analysis of apolipoprotein distribution among different lipoprotein fractions.
(5) Functional assays
Cholesterol efflux assays, LPL activity assays, macrophage foam cell formation assays, LDL oxidation assays, and hepatocyte VLDL secretion assays can be used to validate apolipoprotein-related mechanisms.
6 Products Related to Apolipoprotein Research
Application Module | Cat. No. | Product Name | Grade & Purity | Application Positioning |
ApoA-I detection | Recombinant Apolipoprotein A I Antibody | Recombinant, ExactAb™, Validated, High Performance, See COA | For ApoA-I expression detection, HDL function, and reverse cholesterol transport research | |
ApoA-I functional research | Recombinant Human Apolipoprotein A-I Protein | Carrier Free, His Tag, PBS Only, ≥85%(SDS-PAGE), See COA | For ApoA-I-mediated cholesterol efflux, HDL mimetics, and cellular lipid transport research | |
ApoA-I functional research | Recombinant Human Apolipoprotein A-I Protein | Animal Free, Carrier Free, Bioactive, ActiBioPure™, Azide Free, ≥95%(SDS-PAGE) | For HDL formation, reverse cholesterol transport, and cardiovascular protection mechanism research | |
Native ApoA-I research | Apolipoprotein AI from Human Plasma | Bioactive, Native, ≥95%(SDS-PAGE), See COA | For native ApoA-I function, HDL-related experiments, and cholesterol efflux research | |
Native ApoA-I research | Apolipoprotein AI, Human Plasma | Low Endotoxin, ≥95%(SDS-PAGE), Extinction Coefficient: 1.22 | For ApoA-I function, cell culture, and HDL-related research requiring low endotoxin | |
Human ApoA-I quantitative detection | Human ApolipoProtein A1 (Apo-A1) ELISA Kit | BioReagent | For quantitative detection of ApoA-I in human samples, HDL function, and reverse cholesterol transport research | |
Mouse ApoA-I quantitative detection | Mouse ApolipoProtein A1 (Apo-A1) ELISA Kit | BioReagent | For ApoA-I detection in mouse samples and HDL function research | |
Rat ApoA-I quantitative detection | Rat ApolipoProtein A1 (apo-A1) ELISA Kit | BioReagent | For ApoA-I detection in rat samples and HDL-related research | |
ApoA-II functional research | Apolipoprotein AII from Human Plasma | Bioactive, Native, ≥95%(SDS-PAGE), See COA | For HDL structure, ApoA-II function, and lipoprotein particle composition research | |
Human ApoA-II quantitative detection | Human ApolipoProtein A2 (Apo-A2) ELISA Kit | BioReagent | For quantitative detection of ApoA-II in human samples and HDL particle research | |
ApoA-IV detection | APOA4/Apo-AIV Mouse mAb | ExactAb™, Validated, 0.5 mg/mL | For ApoA-IV expression detection, intestinal lipid absorption, and postprandial lipid metabolism research | |
Native ApoA-IV research | Apolipoprotein AIV, Human Plasma | Extinction Coefficient: 1.0 | For intestinal lipid absorption, chylomicron formation, and postprandial lipid metabolism research | |
Human ApoA-IV quantitative detection | Human ApolipoProtein A4 (Apo-A4) ELISA Kit | BioReagent | For ApoA-IV detection in human samples and intestinal lipid metabolism research | |
Rat ApoA-IV quantitative detection | Rat ApolipoProtein A4 (apo-A4) ELISA Kit | BioReagent | For ApoA-IV detection in rat samples and postprandial lipid metabolism research | |
Human ApoA-V quantitative detection | Human ApolipoProtein A5 (ApoA-5) ELISA Kit | BioReagent | For ApoA-V detection in human samples and triglyceride metabolism research | |
Glycated ApoA detection | Rat Glycated ApolipoProtein A (GApo-A) ELISA Kit | BioReagent | For detecting glycated ApoA in rats, glyco-lipid metabolic abnormalities, and lipoprotein glycation research | |
ApoB detection | Apolipoprotein B Mouse mAb | Carrier Free, ExactAb™, Validated, See COA | For ApoB protein detection, LDL/VLDL-related particle burden, and atherosclerosis research | |
Native ApoB research | Apolipoprotein B from Human Plasma | BioReagent, Native, ≥95%(SDS-PAGE), Pre-lyophilization Protein Concentration | For ApoB-related LDL/VLDL particles, atherosclerosis, and lipoprotein structure research | |
Human ApoB quantitative detection | Human ApolipoProtein B (Apo-B) ELISA Kit | BioReagent | For quantitative detection of ApoB in human samples and ApoB-containing lipoprotein particle research | |
Mouse ApoB quantitative detection | Mouse ApolipoProtein B (Apo-B) ELISA Kit | BioReagent | For ApoB detection in mouse samples and atherosclerosis model research | |
Rat ApoB quantitative detection | Rat ApolipoProtein B (APO-B) ELISA Kit | BioReagent | For ApoB detection in rat samples and ApoB-containing lipoprotein research | |
Rat ApoB100 quantitative detection | Rat ApolipoProtein B100 (apo-B100) ELISA Kit | BioReagent | For rat ApoB100 detection, LDL/VLDL metabolism, and atherosclerosis research | |
Glycated ApoB detection | Rat G ApolipoProtein B (GApo-B) ELISA Kit | BioReagent | For detecting glycated ApoB in rats, glyco-lipid metabolism crosstalk, and atherosclerotic risk research | |
ApoC-I detection | Recombinant Apolipoprotein CI/Apo-CI Antibody | Recombinant, ExactAb™, Validated, 0.8 mg/mL | For ApoC-I expression detection, remnant metabolism, and triglyceride-rich lipoprotein research | |
Native ApoC-I research | Apolipoprotein CI from Human Plasma | BioReagent, Native, ≥95%(SDS-PAGE), Pre-lyophilization Protein Concentration: See COA | For ApoC-I-related lipoprotein receptor binding, remnant metabolism, and lipoprotein remodeling research | |
Human ApoC-I quantitative detection | Human ApolipoProtein C1 (Apo-C1) ELISA Kit | BioReagent | For quantitative detection of ApoC-I in human samples and remnant metabolism research | |
Native ApoC-II research | Apolipoprotein CII from Human Plasma | BioReagent, Native, ≥95%(SDS-PAGE), Pre-lyophilization Protein Concentration: See COA | For LPL activation, triglyceride hydrolysis, and triglyceride-rich lipoprotein metabolism research | |
Human ApoC-II quantitative detection | Human ApolipoProtein C2 (Apo-C2) ELISA Kit | BioReagent | For ApoC-II detection in human samples and LPL activation-related research | |
Native ApoC-III research | Apolipoprotein CIII from Human Plasma | BioReagent, Native, ≥95%(SDS-PAGE), Pre-lyophilization Protein Concentration: See COA | For ApoC-III inhibition of triglyceride clearance, remnant lipoproteins, and hypertriglyceridemia research | |
Native ApoC-III research | Apolipoprotein CIII from Human Plasma | BioReagent, Native, ≥95%(SDS-PAGE), See COA | For ApoC-III function, remnant lipoprotein clearance, and metabolic syndrome-related research | |
Human ApoC-III quantitative detection | Human ApolipoProtein C3 (Apo-C3) ELISA Kit | BioReagent | For ApoC-III detection in human samples, hypertriglyceridemia, and remnant metabolism research | |
Mouse ApoC-III quantitative detection | Mouse ApolipoProtein C3 (Apo-C3) ELISA Kit | BioReagent | For ApoC-III detection in mouse samples and hypertriglyceridemia model research | |
ApoD detection | Recombinant Apo-D Antibody | Recombinant, ExactAb™, Validated, See COA | For ApoD expression detection, neural stress, and lipid binding-related research | |
ApoD functional research | Recombinant Human Apo-D Protein | Animal Free, Carrier Free, His Tag, ≥90%(SDS-PAGE) | For ApoD lipid binding, neural stress, and oxidative injury research | |
Human ApoD quantitative detection | Human ApolipoProtein D (Apo-D) ELISA Kit | BioReagent | For ApoD detection in human samples, neural stress, and lipid binding-related research | |
Rat ApoD quantitative detection | Rat ApolipoProtein D (apo-D) ELISA Kit | BioReagent | For ApoD detection in rat samples and neural/lipid metabolism research | |
ApoE detection | Recombinant Apolipoprotein E Antibody | Recombinant, ExactAb™, Validated, See COA | For ApoE expression detection, lipid metabolism, neurometabolism, and tissue localization research | |
ApoE detection | Recombinant Apolipoprotein E Antibody | KO Validation | For ApoE-specific detection, knockout model validation, and tissue expression analysis | |
ApoE3 functional research | Recombinant Human Apolipoprotein E3 Protein | Animal Free, Carrier Free, Bioactive, ActiBioPure™, His Tag, ≥95%(SDS-PAGE), See COA | For ApoE3-mediated remnant clearance, neural lipid transport, and ApoE isoform control research | |
ApoE3 functional research | Recombinant Human Apolipoprotein E3 Protein | Animal Free, Carrier Free, Bioactive, ActiBioPure™, His Tag, ≥95%(SDS-PAGE) | For ApoE3 function, receptor binding, lipid transport, and neurometabolism research | |
Native ApoE research | Apolipoprotein E from Human Plasma | Bioactive, Native, ≥95%(SDS-PAGE), See COA | For ApoE-mediated remnant clearance, lipid transport, and neurometabolism research | |
ApoE4 research | Apolipoprotein E4 human | ≥90%(SDS-PAGE&HPLC), lyophilized powder,recombinant,expressed in E. coli | For ApoE4 isoform, Alzheimer’s disease risk, Aβ metabolism, and neuroinflammation research | |
Human ApoE quantitative detection | Human Apolipoprotein E/ApoE ELISA Kit | BioReagent | For detecting ApoE levels in human serum, plasma, or related samples | |
Human ApoE quantitative detection | Human ApolipoProtein E (Apo-E) ELISA Kit | BioReagent | For quantitative detection of ApoE in human samples and lipid metabolism/neurometabolism research | |
Human APOE detection | Human APOE ELISA Kit | Bioactive, for Enzyme immunoassay(ELISA), for ELISA | For quantitative detection of APOE in human samples and ApoE-related metabolism research | |
Mouse ApoE quantitative detection | Mouse ApolipoProtein E (Apo-E) ELISA Kit | BioReagent | For ApoE detection in mouse samples and atherosclerosis or neurometabolic model research | |
Rat ApoE quantitative detection | Rat ApolipoProtein E (apo-E) ELISA Kit | BioReagent | For ApoE detection in rat samples and lipid metabolism/neurometabolism research | |
ApoE receptor-related research | Recombinant ApoER2 Antibody | Recombinant, ExactAb™, KD Validation, Validated, See COA | For ApoER2 detection, ApoE receptor-related lipid transport, neural signaling, and receptor function research | |
ApoF detection | APOF Antibody | Carrier Free, ExactAb™, Validated, 1.0 mg/mL | For ApoF expression detection and lipoprotein metabolism-related research | |
ApoH detection | Recombinant Apo-H Antibody | Recombinant, ExactAb™, Validated, High Performance, See COA | For ApoH/β2-glycoprotein I detection, phospholipid binding, coagulation, and immune-related research | |
ApoH functional research | Recombinant Human Apolipoprotein H Protein | Animal Free, Carrier Free, Bioactive, ActiBioPure™, His Tag, ≥95%(SDS-PAGE) | For ApoH/β2-glycoprotein I-related lipid binding, coagulation, and immune mechanism research | |
Human ApoH quantitative detection | Human ApolipoProtein H (Apo-H) ELISA Kit | BioReagent | For ApoH detection in human samples and coagulation, immunity, and antiphospholipid-related research | |
Mouse ApoH quantitative detection | Mouse ApolipoProtein H (Apo-H) ELISA Kit | BioReagent | For ApoH detection in mouse samples and coagulation/immunity-related research | |
ApoL1 detection | Recombinant Apolipoprotein L1/APOL1 Antibody | Recombinant, ExactAb™, Validated, 0.5 mg/mL | For ApoL1 expression detection, kidney disease risk, and inflammation-related research | |
APOLD1 detection | Human ApolipoProtein L Domain Containing 1 (APOLD1) ELISA Kit | BioReagent | For APOLD1 quantitative detection, endothelial response, and vascular-related research | |
ApoM detection | Recombinant ApoM Antibody | Recombinant, ExactAb™, Validated, Lot by Lot | For ApoM protein detection, HDL-S1P axis, and endothelial barrier research | |
ApoM functional research | Recombinant Human Apolipoprotein M Protein | Carrier Free, His Tag, ≥90%(SDS-PAGE) | For ApoM-S1P axis, HDL function, endothelial barrier, and inflammatory regulation research | |
Human ApoM quantitative detection | Human ApolipoProtein M (APO-M) ELISA Kit | BioReagent | For ApoM detection in human samples, HDL-S1P axis, and endothelial function research | |
Mouse ApoM quantitative detection | Mouse ApolipoProtein M (Apo-M) ELISA Kit | BioReagent | For ApoM detection in mouse samples and HDL/endothelial barrier research | |
Rat ApoM quantitative detection | Rat ApolipoProtein M (apo-M) ELISA Kit | BioReagent | For ApoM detection in rat samples and HDL-S1P axis research | |
ApoO-like detection | Apolipoprotein O like Antibody | Carrier Free, ExactAb™, Validated, 1.0 mg/mL | For ApoO-like protein expression detection and lipid metabolism-related mechanism research | |
Clusterin/ApoJ detection | Recombinant Clusterin Antibody | Recombinant, ExactAb™, Validated, 0.1 mg/mL | For Clusterin/ApoJ expression detection, neurodegenerative diseases, and proteostasis research | |
Clusterin/ApoJ functional research | Recombinant Human Clusterin Protein | Animal Free, Carrier Free, Bioactive, ActiBioPure™, Azide Free, High Performance, His Tag, ≥90%(SDS-PAGE) | For Clusterin/ApoJ-related neuroprotection, proteostasis, and lipid transport research |
7 Common Questions in Apolipoprotein Research
7.1 Are ApoB and LDL-C the Same Concept?
No. LDL-C reflects the cholesterol content carried by LDL particles, while ApoB reflects the number of ApoB-containing lipoprotein particles. If each particle carries less cholesterol, LDL-C may not be high, but ApoB may still be elevated, indicating a high particle number.
7.2 Does Increased HDL-C Always Indicate Enhanced Protective Function?
Not necessarily. HDL-C only indicates the amount of cholesterol carried by HDL and cannot fully represent HDL function. HDL cholesterol efflux capacity, anti-inflammatory activity, and antioxidant function may better reflect protective effects than HDL-C values.
7.3 Can ApoE in the Periphery and Brain Be Interpreted Equivalently?
No. Peripheral ApoE mainly participates in remnant lipoprotein clearance, whereas brain ApoE mainly participates in neural lipid transport, Aβ metabolism, synaptic repair, and neuroinflammation. ApoE results from different sample sources should be interpreted by biological level.
7.4 Why Is Elevated ApoC-III Associated with Cardiovascular Risk?
ApoC-III can inhibit hydrolysis of triglyceride-rich lipoproteins and remnant clearance, causing remnant lipoproteins to accumulate in circulation. Remnant particles are rich in cholesterol, can enter the arterial wall, and participate in plaque formation.
7.5 What Is the Significance of the ApoB/ApoA-I Ratio?
The ApoB/ApoA-I ratio reflects the balance between atherogenic lipoprotein particles and HDL-related protective components. An increased ratio usually suggests that lipid transport is more biased toward an atherogenic state, but it should still be interpreted together with clinical context and other lipid indicators.
Apolipoprotein research should integrate lipoprotein particle type, tissue source, metabolic process, and disease context. ApoA-I, ApoB, ApoE, ApoC, ApoD, ApoH, ApoM, ApoL1, and Apo(a) represent different levels of HDL function, atherogenic particle burden, remnant clearance, triglyceride metabolism, neural stress, coagulation and immunity, endothelial protection, kidney risk, and Lp(a) risk, respectively. Only by combining apolipoprotein indicators with lipid profiles, enzyme activity, tissue localization, and functional assays can their roles in metabolic diseases, cardiovascular diseases, and neurodegenerative diseases be accurately interpreted.
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