1
|
Lopes-Virella MF, Bebu I, Hunt KJ, Virella G, Baker NL, Braffett B, Gao X, Lachin JM. Immune Complexes and the Risk of CVD in Type 1 Diabetes. Diabetes 2019; 68:1853-1860. [PMID: 31217176 PMCID: PMC6702641 DOI: 10.2337/db19-0358] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/17/2019] [Indexed: 12/15/2022]
Abstract
We investigated whether the composition of modified forms of LDL in circulating immune complexes (LDL-ICs) was associated with cardiovascular disease (CVD) outcomes, including any CVD, major adverse cardiac and cerebrovascular events (MACCE), myocardial infarction (MI), and coronary artery disease, in type 1 diabetes (T1D). Our results demonstrate that the baseline levels of oxidized LDL (oxLDL), MDA-modified LDL (MDA-LDL), and advanced glycosylation-modified LDL (AGE-LDL) in circulating ICs were associated with the four CVD outcomes in unadjusted models, and adjustment by age and mean HbA1c only resulted in minimal reduction of these associations. After adjustments were made for other cardiovascular risk factors, particularly LDL cholesterol, oxLDL-IC and MDA-LDL-IC remained independently associated with the risk of CVD, and oxLDL-IC was independently associated with the risk of MACCE and MI. In the majority of cases, the baseline levels of modified LDL-IC (measured many years before the occurrence of any CVD event) were associated with the risk of CVD over a 25-year period even after adjustment for other risk factors (including LDL cholesterol). Therefore, modified LDL biomarkers may help identify patients with T1D at high risk for MACCE and CVD events very early in the evolution of the disease, before other signals of disease are apparent.
Collapse
Affiliation(s)
| | - Ionut Bebu
- Biostatistics Center, The George Washington University, Rockville, MD
| | - Kelly J Hunt
- Medical University of South Carolina, Charleston, SC
| | | | | | - Barbara Braffett
- Biostatistics Center, The George Washington University, Rockville, MD
| | - Xiaoyu Gao
- Biostatistics Center, The George Washington University, Rockville, MD
| | - John M Lachin
- Biostatistics Center, The George Washington University, Rockville, MD
| | | |
Collapse
|
2
|
Lopes-Virella MF, Virella G. Modified LDL Immune Complexes and Cardiovascular Disease. Curr Med Chem 2019; 26:1680-1692. [DOI: 10.2174/0929867325666180524114429] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/17/2017] [Accepted: 12/28/2017] [Indexed: 12/17/2022]
Abstract
Modified forms of LDL, both spontaneously formed in the organism or prepared in the laboratory, are immunogenic. As a consequence, antigen-antibody complexes (immune complexes, IC) formed in vivo can be measured in the peripheral blood, and their levels are strong predictors of cardiovascular disease (CVD). It has been possible to generate antibodies that recognize different LDL modifications, allowing the analysis of circulating IC constitution. Clinical studies showed that the antigenic constitution of the IC has a modulating effect on the development of CVD. Patients whose IC react strongly with antibodies to copper oxidized LDL (oxLDL) show progressive development of atherosclerosis as demonstrated by increased intima–media thickness and increased coronary calcification scores. In contrast, patients whose IC react strongly with antibodies to the heavily oxidized malondialdehyde LDL prepared in vitro (MDA-LDL) are at a high risk of acute vascular events, mainly myocardial infarction. In vitro studies have shown that while oxLDL IC induce both cell proliferation and mild to moderate macrophage apoptosis, MDA-LDL IC induce a more marked macrophage apoptosis but not cell proliferation. In addition, MDA-LDL IC induce the release of higher levels of matrix metalloproteinases and TNF than oxLDL IC. High levels of TNF are likely to be a major factor leading to apoptosis and high levels of metalloproteinases are likely to play a role in the thinning of the fibrous cap of the atheromatous plaque. The combination of apoptosis and fibrous cap thinning is a well-known characteristic of vulnerable plaques, which are more prone to rupture and responsible for the majority of acute cardiovascular events.
Collapse
Affiliation(s)
- Maria F. Lopes-Virella
- Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Ralph A. Johnson VA Medical Center, Charleston, SC, United States
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| |
Collapse
|
3
|
Immune complexes containing malondialdehyde (MDA) LDL induce apoptosis in human macrophages. Clin Immunol 2018; 187:1-9. [DOI: 10.1016/j.clim.2017.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 11/22/2022]
|
4
|
Lopes-Virella MF, Hunt KJ, Baker NL, Virella G. High levels of AGE-LDL, and of IgG antibodies reacting with MDA-lysine epitopes expressed by oxLDL and MDA-LDL in circulating immune complexes predict macroalbuminuria in patients with type 2 diabetes. J Diabetes Complications 2016; 30:693-9. [PMID: 26861948 DOI: 10.1016/j.jdiacomp.2016.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/11/2016] [Accepted: 01/12/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND Circulating immune complexes (IC) containing modified forms of LDL (mLDL) are strongly pro-inflammatory and when present in high levels are associated with the development of diabetic complications. OBJECTIVE We investigated whether levels of oxidized LDL (oxLDL), malondialdehyde-LDL (MDA-LDL) and advanced glycation end products-LDL (AGE-LDL) as well as IgG and IgM antibodies reacting with MDA-lysine epitopes expressed by oxLDL and MDA-LDL isolated from circulating IC were associated with progression to macroalbuminuria in type 2 diabetes (VADT cohort). METHODS Levels of mLDL in IC were measured in 905 patients, a median of two years after entry into the study. Participants were followed for an average of 3.7years for renal outcomes. Generalized logistic regression models were used to quantify the association of increased levels of biomarkers and development of abnormal albuminuria. Normal, persistent micro- (ACR ≥30), incident micro- (ACR ≥30) and incident macroalbuminuria (ACR ≥300) were the outcomes of interest. RESULTS AND CONCLUSIONS Patients with macro (n=78) or non-persistent microalbuminuria (n=81) at baseline were excluded. Odds ratios for endpoints in relation to high versus low (defined using a median split) biomarker levels are found in Fig. 1. Our study demonstrates that high levels of AGE-LDL as well as of IgG antibodies (but not IgM antibodies) reacting with MDA-LDL lysine epitopes in circulating IC predict the development of macroalbuminuria in patients with type 2 diabetes. These data support the pathogenic role of modified LDL IgG antibodies but not the protective role of modified LDL IgM antibodies.
Collapse
Affiliation(s)
- Maria F Lopes-Virella
- Department of Medicine and Laboratory Services, Medical University of South Carolina and Ralph H. Johnson VA Medical Center, Charleston, SC.
| | - Kelly J Hunt
- Department of Public Health Services, Medical University of South Carolina, Charleston, SC
| | - Nathaniel L Baker
- Department of Public Health Services, Medical University of South Carolina, Charleston, SC
| | - Gabriel Virella
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC
| |
Collapse
|
5
|
Hörl G, Froehlich H, Ferstl U, Ledinski G, Binder J, Cvirn G, Stojakovic T, Trauner M, Koidl C, Tafeit E, Amrein K, Scharnagl H, Jürgens G, Hallström S. Simvastatin Efficiently Lowers Small LDL-IgG Immune Complex Levels: A Therapeutic Quality beyond the Lipid-Lowering Effect. PLoS One 2016; 11:e0148210. [PMID: 26840480 PMCID: PMC4739583 DOI: 10.1371/journal.pone.0148210] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 01/14/2016] [Indexed: 01/28/2023] Open
Abstract
We investigated a polyethylene glycol non-precipitable low-density lipoprotein (LDL) subfraction targeted by IgG and the influence of statin therapy on plasma levels of these small LDL-IgG-immune complexes (LDL-IgG-IC). LDL-subfractions were isolated from 6 atherosclerotic subjects and 3 healthy individuals utilizing iodixanol density gradient ultracentrifugation. Cholesterol, apoB and malondialdehyde (MDA) levels were determined in each fraction by enzymatic testing, dissociation-enhanced lanthanide fluorescence immunoassay and high-performance liquid chromatography, respectively. The levels of LDL-IgG-IC were quantified densitometrically following lipid electrophoresis, particle size distribution was assessed with dynamic light scattering and size exclusion chromatography. The influence of simvastatin (40 mg/day for three months) on small LDL-IgG-IC levels and their distribution among LDL-subfractions (salt gradient separation) were investigated in 11 patients with confirmed coronary artery disease (CAD). We demonstrate that the investigated LDL-IgG-IC are small particles present in atherosclerotic patients and healthy subjects. In vitro assembly of LDL-IgG-IC resulted in particle density shifts indicating a composition of one single molecule of IgG per LDL particle. Normalization on cholesterol levels revealed MDA values twice as high for LDL-subfractions rich in small LDL-IgG-IC if compared to dominant LDL-subfractions. Reactivity of affinity purified small LDL-IgG-IC to monoclonal antibody OB/04 indicates a high degree of modified apoB and oxidative modification. Simvastatin therapy studied in the CAD patients significantly lowered LDL levels and to an even higher extent, small LDL-IgG-IC levels without affecting their distribution. In conclusion simvastatin lowers levels of small LDL-IgG-IC more effectively than LDL-cholesterol and LDL-apoB levels in atherosclerotic patients. This antiatherogenic effect may additionally contribute to the known beneficial effects of this drug in the treatment of atherosclerosis.
Collapse
Affiliation(s)
- Gerd Hörl
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
- * E-mail:
| | - Harald Froehlich
- Division of Angiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Ulrika Ferstl
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
| | - Gerhard Ledinski
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
| | - Josepha Binder
- Division of Cardiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Gerhard Cvirn
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
| | - Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Christoph Koidl
- Institute of Hygiene, Medical University of Graz, Graz, Austria
| | - Erwin Tafeit
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
| | - Karin Amrein
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Hubert Scharnagl
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Günther Jürgens
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
| | - Seth Hallström
- Institute of Physiological Chemistry, Center of Physiological Medicine, Medical University of Graz, Graz, Austria
| |
Collapse
|
6
|
Lopes-Virella MF, Virella G. Pathogenic role of modified LDL antibodies and immune complexes in atherosclerosis. J Atheroscler Thromb 2013; 20:743-54. [PMID: 23965492 DOI: 10.5551/jat.19281] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
There is strong evidence supporting a key role of the adaptive immune response in atherosclerosis, given that both activated Th cells producing predominantly interferon-γ and oxidized LDL (oxLDL) and the corresponding antibodies have been isolated from atheromatous plaques. Studies carried out using immune complexes (IC) prepared with human LDL and rabbit antibodies have demonstrated proatherogenic and pro-inflammatory properties, mostly dependent on the engagement of Fcγ receptors Ⅰ and Ⅱ in macrophages and macrophage-like cell lines. Following the development of a methodology for isolating modified LDL (mLDL) antibodies from serum and isolated IC, it was confirmed that antibodies reacting with oxLDL and advanced glycation end product-modified LDL are predominantly IgG of subtypes 1 and 3 and that mLDL IC prepared with human reagents possesses pro-inflammatory and proatherogenic properties. In previous studies, LDL separated from isolated IC has been analyzed for its modifications, and the reactivity of antibodies isolated from the same IC with different LDL modifications has been tested. Recently, we obtained strong evidence suggesting that the effects of mLDL IC on phagocytic cells are modulated by the composition of the mLDL. Clinical studies have shown that the level of mLDL in circulating IC is a strong predictor of cardiovascular disease (CVD) and, in diabetic patients, other significant complications, such as nephropathy and retinopathy. In conclusion, there is convincing ex vivo and clinical data supporting the hypothesis that, in humans, the humoral immune response to mLDL is pathogenic rather than protective.
Collapse
|