Proinflammatory high-density lipoprotein as a biomarker for atherosclerosis in patients with systemic lupus erythematosus and rheumatoid arthritis

The role of dysfunctional HDL in atherosclerosis

This review focuses on HDL function in modulating LDL oxidation and LDL-induced inflammation. Dysfunctional HDL has been identified in animal models and humans with chronic inflammatory diseases including atherosclerosis. The loss of antiinflammatory function correlated with a loss of function in reverse cholesterol transport. In animal models and perhaps in humans, dysfunctional HDL can be improved by apoA-I mimetic peptides that bind oxidized lipids with high affinity.

Inflammatory lipids as a target for therapy in the rheumatic diseases

As patients with autoimmune rheumatic diseases live longer due to improved therapies and preventive measures, death and disability from cardiovascular events are increasing. Patients with rheumatoid arthritis and systemic lupus erythematosus have an increased risk of atherosclerosis that persists even after accounting for traditional cardiac risk factors. Recent studies strongly suggest that the mechanism is due in part to increased levels of oxidized lipids (such as oxidized low density lipoprotein and pro-inflammatory high density lipoproteins) which cause the inflammatory cascade that ultimately leads to plaque formation. The objective of this review is to discuss how inflammatory lipids contribute to the increased risk of atherosclerosis in rheumatoid arthritis and systemic lupus erythematosus, as well as to propose that these oxidized lipids are a rational target for therapeutic intervention in autoimmune diseases. Published literature was examined to review treatments for pro-inflammatory lipids in autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. In conclusion, it is possible that these oxidized lipids may also contribute to increased disease manifestations in rheumatic conditions. Several new and existing therapies, including statins and high density lipoprotein-associated protein peptide mimetics such as D-4F (apoA-1) target these oxidized lipids and may be useful in both preventing atherosclerosis and treating inflammation in patients with rheumatic diseases.

Are there models for predicting accelerated atherogenesis in systemic lupus erythematosus?

Identification of patients with systemic lupus erythematosus who are at risk of complications related to accelerated atherogenesis is extremely important in order to put in place preventive or therapeutic measures that will greatly improve quality of life and outcomes. The severity of accelerated atherogenesis is worsened by corticosteroids, but this complication might also occur in the absence of steroid therapy. In order to identify patients at risk of accelerated atherogenesis, Karp et al. have proposed a statistical model, based on Framingham data, steroid dosing, Systemic Lupus Erythematosus Disease Activity Index scores and predicted events related to coronary artery disease. This commentary critically reviews this model.

Altered lipoprotein metabolism in chronic inflammatory states: proinflammatory high-density lipoprotein and accelerated atherosclerosis in systemic lupus erythematosus and rheumatoid arthritis

In this review, the authors discuss the formation and structure of high-density lipoproteins (HDLs) and how those particles are altered in inflammatory or stress states to lose their capacity for reverse cholesterol transport and for antioxidant activity. In addition, abnormal HDLs can become proinflammatory (piHDLs) and actually contribute to oxidative damage. The assay by which piHDLs are identified involves studying the ability of test HDLs to prevent oxidation of low-density lipoproteins. Finally, the authors discuss the potential role of piHDLs (found in some 45% of patients with systemic lupus erythematosus and 20% of patients with rheumatoid arthritis) in the accelerated atherosclerosis associated with some chronic rheumatic diseases.

Dietary alpha-cyclodextrin lowers low-density lipoprotein cholesterol and alters plasma fatty acid profile in low-density lipoprotein receptor knockout mice on a high-fat diet

High dietary intake of saturated fat and cholesterol, and elevated low-density lipoprotein cholesterol levels are some of the modifiable risk factors for cardiovascular disease. Alpha-cyclodextrin (a-CD) when given orally has been shown in rats to increase fecal saturated fat excretion and to reduce blood total cholesterol levels in obese hypertriglyceridemic subjects with type 2 diabetes mellitus. In this study, the effects of dietary a-CD on lipid metabolism in low-density lipoprotein receptor knockout mice were investigated. Low-density lipoprotein receptor knockout mice were fed a "Western diet" (21% milk fat) with or without 2.1% of a-CD (10% of dietary fat content) for 14 weeks. At sacrifice, there was no difference in body weight; but significant decreases were observed in plasma cholesterol (15.3%), free cholesterol (20%), cholesterol esters (14%), and phospholipid (17.5%) levels in mice treated with alpha-CD compared with control mice. The decrease in total cholesterol was primarily in the proatherogenic apolipoprotein B-containing lipoprotein fractions, with no significant change in the high-density lipoprotein fraction. Furthermore, alpha-CD improved the blood fatty acid profile, reducing the saturated fatty acids (4.5%) and trans-isomers (11%) while increasing (2.5%) unsaturated fatty acids. In summary, the addition of alpha-CD improved the lipid profile by lowering proatherogenic lipoproteins and trans-fatty acids and by decreasing the ratio of saturated and trans-fatty acids to polyunsaturated fatty acids (-5.8%), thus suggesting that it may be useful as a dietary supplement for reducing cardiovascular disease.

Atherosclerosis in rheumatoid arthritis and systemic lupus erythematosus

PURPOSE OF REVIEW

Our aim was to review recent studies that address the increased risk of atherosclerosis and coronary heart disease in patients with rheumatoid arthritis and systemic lupus erythematosus. We examine the strength of this association, how inflammation mediates this increased risk and what impact therapies may have.

RECENT FINDINGS

Atherosclerosis is more prevalent and accelerated in both conditions. Indeed the process may actually precede the onset of clinical inflammatory disease. Metabolic alterations include insulin resistance and the generation of proinflammatory HDL. In addition, inflammatory mechanisms central to both rheumatoid arthritis and systemic lupus erythematosus such as macrophage activation, interferon-1 and complement deficiency may contribute to atherogenesis. There is still no consensus as to the value of primary preventive strategies in these conditions. However, drugs such as hydroxychloroquine seem to modify coronary heart disease risk and may improve survival. The recently developed antitumour necrosis factor drugs may also reduce coronary heart disease risk but biomarker studies to date have been inconclusive.

SUMMARY

There is an urgent need for clinical trials to examine both the lipid-lowering and inflammatory hypotheses of atherosclerosis in rheumatoid arthritis and systemic lupus erythematosus. Novel targeted therapies in development may also have a major impact on future coronary heart disease risk in these conditions.

A pilot study of subclinical coronary atherosclerosis in systemic sclerosis: coronary artery calcification in cases and controls

OBJECTIVE

Systemic sclerosis (SSc) is associated with vasculopathy and endothelial cell injury, which could potentially increase the risk of coronary atherosclerosis. Multidetector computed tomography, a noninvasive procedure, generates a coronary calcium score (CCS) as a marker for coronary atherosclerosis. Serum proinflammatory high-density lipoprotein (piHDL) is a potential novel marker of atherosclerotic risk. The objective of the pilot study was to determine 1) the prevalence of subclinical coronary atherosclerosis in SSc and 2) serum piHDL levels as a potential novel marker of atherosclerotic risk in SSc.

METHODS

A cross-sectional study of 17 patients with SSc and 17 age-, sex-, and race-matched healthy controls in Cincinnati, Ohio, was conducted. Measurements included CCS; body mass index; lipid profile; and serum levels of high-sensitivity C-reactive protein, homocysteine, and piHDL.

RESULTS

Patients with SSc were slightly older (mean 52.8 years) than control subjects (mean 50.6 years; P = 0.01). Coronary calcium was found in 12 participants (9 with SSc, 3 controls; P = 0.03). The mean +/- SD CCS in patients with SSc was significantly greater than the controls (126.6 +/- 251.0 versus 14.7 +/- 52.2; P = 0.003). Five patients with SSc (29%), but no controls, had detectable levels of piHDL (P = 0.06).

CONCLUSION

Prevalence of subclinical coronary atherosclerosis is greater in patients with SSc compared with healthy controls. These findings should be confirmed in a larger study.

Rheumatoid arthritis and cardiovascular disease

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease affecting approximately 1% of the adult general population. Cardiovascular disease is recognized as the leading cause of death in RA patients, accounting for nearly 40% of their mortality. Patients with RA are at a twofold increased risk for myocardial infarction and stroke, with risk increasing to nearly threefold in patients who have had the disease for 10 years or more. Congestive heart failure appears to be a greater contributor to excess mortality than ischemia. This increased cardiovascular disease risk in RA patients seems to be independent of traditional cardiovascular risk factors. Pathogenic mechanisms include pro-oxidative dyslipidemia, insulin resistance, prothrombotic state, hyperhomocysteinemia, and immune mechanisms such as T-cell activation that subsequently lead to endothelial dysfunction, a decrease in endothelial progenitor cells, and arterial stiffness, which are the congeners of accelerated atherosclerosis observed in RA patients. This paper discusses pathogenic mechanisms, effects of methotrexate, tumor necrosis factor antagonists, steroids, and statins, with a perspective on therapy.

Atherosclerosis and systemic lupus erythematosus: the role of altered lipids and of autoantibodies

The accelerated atherosclerosis that occurs in some patients with systemic lupus erythematosus (SLE) has a complex pathogenesis, including alterations in lipids, inflammation and the immune system. In this article, we review the evidence that peroxidase-related alteration of normal, protective high-density lipoprotein (HDL) converts them to pro-inflammatory HDL (piHDL), characterized by lower content of the cholesterol transport lipoprotein ApoA1 and impaired function of the antioxidant enzyme paroxonase, which prevents oxidation of low-density lipoprotein (LDL). Forty-five per cent of women with SLE have piHDL compared with 20% of patients with rheumatoid arthritis and 4% of healthy controls. The presence of piHDL increases risk for coronary artery events and carotid artery plaque. Another result of lipid oxidation in patients with SLE is generation of highly oxidized LDL and phospholipids (PL), probably stimulating antibodies to OxPL phospholipids. These antibodies along with promoting thrombosis also interfere with deposits of Annexin V onto endothelial cells, which probably promote increased instability of atherosclerotic plaque. Thus, piHDL and anti-OxPL promote plaque formation, plaque instability and thrombosis, accounting for some of the large increase in atherosclerosis and coronary artery events in SLE.

Treatment with an apolipoprotein A-1 mimetic peptide in combination with pravastatin inhibits collagen-induced arthritis

To evaluate the therapeutic potential of an apolipoprotein A-1 (apoA-1) mimetic peptide, D-4F, in combination with pravastatin in collagen-induced arthritis (CIA), syngeneic Louvain rats were immunized with type II collagen and randomized to vehicle control, D-4F monotherapy, pravastatin monotherapy, or D-4F + pravastatin combination therapy. Clinical arthritis activity was evaluated and radiographs, type II collagen antibody titers, cytokine/chemokine levels, and HDL function analysis were obtained. There was significant reduction in clinical severity scores in the high and medium dose D-4F + pravastatin groups compared to controls (p< or =0.0001). Reduction in erosive disease occurred in the medium/high dose combination groups compared to non-combination groups (p< or =0.01). Favorable changes in cytokines/chemokines were noted with treatment, and response to combination D-4F/pravastatin therapy was associated with improvement in HDL's anti-inflammatory properties. Combination D-4F/pravastatin significantly reduced clinical disease activity in CIA, and may have dual therapeutic potential in other autoimmune diseases with increased cardiovascular morbidity and mortality.

Safety, pharmacokinetics, and pharmacodynamics of oral apoA-I mimetic peptide D-4F in high-risk cardiovascular patients

Patients with coronary heart disease or equivalent risk received a single dose of 30, 100, 300, or 500 mg of unformulated D-4F (n = 8, each dose) or placebo (n = 8) under fasting conditions. An additional 10 patients received 500 mg (n = 8) or placebo (n = 2) with a low-fat meal. There were no significant trends in any safety parameter. D-4F was detectable in plasma at all doses with a T(max) of 30 min, 1 h, and 2 h for 30, 100, and > or = 300 mg, respectively. The area under the curve((0-t)) was 27.81 ng/hr/ml and 54.71 ng/hr/ml for the 300 mg and 500 mg dose groups, respectively, and 17.96 ng/hr/ml for the 500 mg dose given with food. HDL from each time point for each subject was tested for its ability to inhibit LDL-induced monocyte chemotactic activity in cultures of human aortic endothelial cells. The values obtained were normalized to 1.0 for LDL alone to obtain the HDL inflammatory index. This index significantly improved at 4 h at the 300 mg dose and at 2 h at the 500 mg dose compared with placebo (P < 0.05). There were no changes in plasma lipid or lipoprotein levels. We conclude that unformulated D-4F has low bioavailability that is improved under fasting conditions, and that a single dose of D-4F is safe and well tolerated and may improve the HDL anti-inflammatory index.

Atherosclerosis and systemic lupus erythematosus: mechanistic basis of the association

As patients with Systemic Lupus Erythematosus (SLE) live longer due to improved therapies and preventive measures, death and disability from cardiovascular events are increasing. Patients with SLE have an increased risk of atherosclerosis that persists even after accounting for traditional cardiac risk factors. Recent studies strongly suggest that the mechanism is due in part to a combination of inflammatory and immune mechanisms. Contributory factors include increased levels of oxidized lipids (such as oxidized LDL and pro-inflammatory HDL), upregulation of adhesion molecules, and upregulation of cytokines such as MCP-1, TNF-alpha, IFN-gamma, IL-1, and IL-12. Autoanitbodies to oxidized lipids and immune complexes may also play a role in the development of atherosclerosis in SLE. As in the pathogenesis of many lupus disease processes, the increased risk of atherosclerosis seen in SLE is likely due to the complex interplay of many of these inflammatory and immune mediators.

Carotid atherosclerotic alterations in systemic lupus erythematosus patients treated at a Brazilian university setting

To determine the frequency of carotid plaque and intima-media thickness (IMT) in patients with systemic lupus erythematosus (SLE) and their association with risk factors in a Brazilian university setting. Carotid plaque and IMT were identified and measured by ultrasonography. Traditional risk factors and lupus-related factors were analysed. One hundred and seventy-two patients (women = 96%, age = 38 ± 11 years) were evaluated. The frequency of carotid plaque was 9.3%. The median (IR) IMT was 0.60 mm (0.54—0.71 mm). Age, family history (FH) of premature coronary disease, low-density cholesterol (LDL-c) >100 mg/dL, hypertriglyceridemia, diabetes, hypertension, smoking, postmenopause, number of risk factors, Framingham risk score, age at diagnosis, duration of lupus, mucocutaneous manifestations and duration of prednisone use were associated with plaque ( P < 0.05), univariate analysis. Nephritis, immunosuppressive therapy, intravenous methylprednisolone and a higher average daily dose of prednisone were associated with the absence of plaque. Independent predictors of plaque were smoking ( P = 0.004), LDL-c >100 mg/dL ( P = 0.044), Framingham score ( P = 0.006) and absence of immunosuppressive therapy ( P = 0.032). There was an independent correlation between IMT and age ( P < 0.001) and duration of prednisone use ( P = 0.020). Subclinical atherosclerosis was associated with traditional risk and SLE-related factors, especially the absence of immunosuppressive therapy. The present study suggests that the levels of LDL-c should be kept under 100mg/dL in lupus. Lupus (2008) 17, 105—113.

Early treatment reduces the cardiovascular risk factors in newly diagnosed rheumatoid arthritis patients

OBJECTIVE

To investigate subclinical atherosclerosis and the effect of treatment in patients with early rheumatoid arthritis (RA).

PATIENTS AND METHODS

Forty patients with early RA who met the revised American College of Rheumatology (ACR) criteria and disease duration of <1 year were included in the study. Smokers and patients with classical risk factors for atherosclerosis were excluded. The serum levels of total cholesterol (TC), triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol were determined in all patients before and after 1 year of therapy. Carotid artery intima-media thickness (IMT) and carotid plaque were measured before and after treatment. RA disease activity was measured using the 28 joint indices score (DAS-28) and clinical improvement was determined by the ACR response criteria. Forty-five age- and sex-matched nonsmoking volunteers were used as controls. All patients were treated with methotrexate and prednisone.

RESULTS

RA patients had a baseline mild dyslipidemia characterized by a decrease in serum HDL-C levels and a high TC/HDL-C atherogenic ratio compared with controls. Both lipid parameters were significantly improved after treatment (P<0.01). Common carotid artery IMTs at baseline were higher in RA patients compared with controls (P<0.05). After 1 year of therapy there was a significant decrease in the IMTs (P<0.001). Thirty-five patients (88%) achieved the ACR 20%, while 30 (75%) reached the ACR 50% response criteria. A significant decrease of DAS-28 was observed after treatment (P<0.03).

CONCLUSIONS

The atherogenic lipid profile and subclinical atherosclerosis are features of early RA, which improved after therapy. Early intervention and control of the disease activity may reduce the risk of atherosclerosis and cardiovascular events in patients with RA.

High-density lipoprotein: a fall from grace?

Based on a plethora of in-vitro and in-vivo research data, high-density lipoprotein cholesterol (HDL) has been regarded as universally atheroprotective. Consequently, pharmacologically mediated HDL increase has emerged as a potential means to improve prevention and treatment of patients with atherosclerotic vascular disease. In particular, inhibition of cholesteryl ester transfer protein (CETP) was considered a promising strategy. Recently, the unanticipated and disappointing results of four large clinical trials with the CETP inhibitor torcetrapib have necessitated refinement of the HDL hypothesis. In addition, the progressive insight that HDL may actually be predominantly a carrier molecule of a wide array of proteins rather than merely a cholesterol-transporter has resulted in the interest to look beyond HDL levels alone. Here we will discuss the impact of recent developments on the HDL hypothesis as well as the advent of even more recent therapeutic developments in the HDL field.

Targeting the anti-inflammatory effects of high-density lipoprotein

The effects of systemic inflammation can impair the anti-inflammatory functions of high-density lipoprotein (HDL) particles. In patients with atherosclerosis and/or inflammatory conditions, HDLs can be modified such that they paradoxically increase the recruitment and activation of macrophages, upregulate the expression of endothelial cell adhesion molecules, and participate in the oxidation of low-density lipoproteins (LDLs). Statins, apolipoprotein A-I mimetic peptides, and therapeutic lifestyle changes appear to mitigate these proinflammatory features of HDLs. In the future, characterizing and targeting functional aspects of HDLs may prove to offer therapeutic advantages over current treatment strategies.

Atheroma and systemic lupus erythematosus

Epidemiologic data indicate a large increase in cardiovascular risk in patients with systemic lupus erythematosus (SLE). Non-invasive investigations show increases in intima-media thickness, carotid plaque, and coronary artery calcifications in patients with SLE, compared to controls. Conventional cardiovascular risk factors may fail to fully explain the high cardiovascular risk in SLE patients. Immunological disturbances and inflammation may indirectly contribute to the risk of cardiovascular disease by inducing dyslipidemia and/or insulin resistance. The potential role for glucocorticoid therapy is controversial. Effective control of the disease would be expected to decrease the cardiovascular morbidity and mortality rates. Careful attention should be given to controlling conventional risk factors such as obesity, smoking, and physical inactivity. Hypertension and/or dyslipidemia should be treated optimally. The appropriateness of antiplatelet therapy should be assessed.

Lipoprotein inflammatory properties and serum amyloid A levels but not cholesterol levels predict lesion area in cholesterol-fed rabbits

Rabbits on a 1% cholesterol diet received injections of vehicle with or without D-4F or L-4F. After 1 month, the percent of aorta with atherosclerotic lesions was 24 +/- 15% (vehicle), 10 +/- 6% (D-4F) (P < 0.01 vs. vehicle), and 13 +/- 9% (L-4F) (P < 0.05 vs. vehicle). Inflammatory indexes for HDL and LDL were determined by measuring monocyte chemotactic activity after adding rabbit lipoproteins to human endothelial cells. HDL-inflammatory index (HII) and LDL-inflammatory index (LII), respectively, were 1.39 +/- 0.24; 1.35 +/- 0.29 (vehicle), 0.67 +/- 0.26; 0.63 +/- 0.38 (D-4F) (P < 0.001 vs. vehicle), and 0.67 +/- 0.2; 0.68 +/- 0.32 (L-4F) (P < 0.01 vs. vehicle). Serum amyloid A (SAA) levels were 95 +/- 39, 8 +/- 22, and 7 +/- 19 mug/ml, respectively, for vehicle, D-4F, and L-4F (P < 0.001 vs. vehicle). There was no correlation between lesion area and total plasma or HDL-cholesterol levels. In contrast, there was a positive correlation with HII, LII, and SAA (P = 0.002, P = 0.0026, P = 0.0079, respectively). HII correlated closely with SAA levels (r = 0.6616; r(2) = 0.4377, P < 0.0001). Thus, HII, LII, and SAA are better predictors of lesion area than are total plasma or HDL-cholesterol levels in cholesterol-fed rabbits.

Precocious atherosclerosis in rheumatoid arthritis: role of traditional and disease-related cardiovascular risk factors

The risk of cardiovascular (CV) disease increases in patients with rheumatoid arthritis (RA). This is due to a number of different triggers including traditional and disease-related factors. Among established risk factors for CV disease, smoking may exert a more dangerous effect on arterial wall in RA than in the general population by a synergic effect with inflammatory processes of the disease. Although persistent inflammation and immune dysregulation of RA may contribute to favor other well-known CV risk factors, such as dyslipidemia, it is now clear that the disease itself represents an independent risk factor for CV disease by the action of RA chronic inflammatory process as well as humoral and cell-mediated immune mechanisms. There is evidence that CV risk is associated with severity and extension of the disease and it is of interest the fact that the presence of circulating anticyclic citrullinated peptide antibodies appears to be associated with stronger evidence of subclinical atherosclerosis in RA.

Modifying the anti-inflammatory effects of high-density lipoprotein

The anti-inflammatory effects of high-density lipoproteins (HDL) are well documented and include inhibition of low-density lipoprotein (LDL) oxidation, reduction of inflammatory cytokines and vascular leukocyte adhesion molecules, and participation in innate immunity. However, certain conditions, including coronary disease, diabetes mellitus, systemic inflammation, and a diet high in saturated fat, are associated with modification of HDL such that it paradoxically enhances LDL oxidation and/or vascular inflammation. Treatment with statins and/or apolipoprotein A1 mimetic peptides improves HDL's anti-inflammatory functions, and these as well as other medications may represent a novel pathway through which to target atherosclerosis.

Enhanced atherogenesis and altered high density lipoprotein in patients with Crohn's disease

A chronic inflammatory state is a risk factor for accelerated atherogenesis. The aim of our study was to explore whether Crohn's disease (CD), characterized by recurrent inflammatory episodes, is also associated with accelerated atherogenesis. In 60 CD patients and 122 matched controls, carotid intima media thickness (IMT), a validated marker for the burden and progression of atherosclerosis, was assessed ultrasonographically. Additional subgroup analyses, including plasma levels of acute phase reactants and HDL protein profiling, were performed in 11 consecutive patients with CD in remission, 10 patients with active CD, and 15 healthy controls. Carotid IMT in patients with CD was increased compared with healthy volunteers: 0.71 (0.17) versus 0.59 (0.14) mm (P < 0.0001), respectively. In the subgroup analysis, HDL levels in controls and patients in remission were identical [(1.45 (0.48) and 1.40 (0.46) mmol/l; P = 0.797], whereas HDL during exacerbation was profoundly reduced: 1.02 (0.33) (P = 0.022). HDL from patients with active CD and CD patients in remission was characterized by a reduced ability to attenuate oxidation compared with controls (P = 0.008 and P = 0.024 respectively). Patients with CD have increased IMT compared with matched controls, indicative of accelerated atherogenesis. The changes during CD exacerbation in terms of HDL concentration and composition imply a role for impaired HDL protection in these patients.

HDL-inflammatory index correlates with poor outcome in hemodialysis patients

Oxidative stress and cardiovascular disease are risk factor of patients with chronic kidney disease (CKD) on maintenance hemodialysis. We used the fluorescence of low-density lipoprotein as an index of its proinflammatory potential to examine any role that high-density lipoprotein (HDL) might have in promoting this effect. The total body fat of the patients was measured by means of near-infrared interactance and their quality of life by means of SF36 questionnaires. In 189 randomly selected patients, followed for 30 months, HDL was found to be significantly anti-inflammatory but with a large standard deviation. Fully 17% of the patients had a decidedly proinflammatory index along with inferior SF36 scores. The patients were divided into 10% increments of total body fat percentages up to 40%. HDL was found to be progressively proinflammatory the higher the body fat content. Patients with a higher HDL proinflammatory index had a higher 30-month adjusted hazard ratio for death than those whose HDL were seen to be anti-inflammatory. Our findings suggest an important role of inflammatory HDL in patients with CKD leading to poor outcome.

The paradox of dysfunctional high-density lipoprotein

PURPOSE OF REVIEW

This review addresses how, in atherosclerosis or systemic inflammation, HDL can lose its usual atheroprotective characteristics and even paradoxically assume proinflammatory properties.

RECENT FINDINGS

Specific chemical and structural changes within HDL particles can impede reverse cholesterol transport, enhance oxidation of LDL, and increase vascular inflammation. HDL may be viewed as a shuttle that can be either anti-inflammatory or proinflammatory, depending on its cargo of proteins, enzymes, and lipids. Some therapeutic approaches that reduce coronary risk, such as statins and therapeutic lifestyle changes, can favorably moderate the characteristics of proinflammatory HDL. In addition, apolipoprotein A-I mimetic peptides and other compounds that target functional aspects of HDL may offer novel approaches to reduction in cardiovascular risk.

SUMMARY

Current data suggest that under some conditions HDL can become dysfunctional and even proinflammatory, but this characterization can change with resolution of systemic inflammation or use of certain treatments.

The role of preventive cardiology in systemic lupus erythematosus

With improved therapeutic advances in the care of systemic lupus erythematosus patients, cardiovascular disease has emerged as a leading cause of death. Premature atherosclerosis in lupus patients is probably an interaction between traditional cardiovascular risk factors, inflammatory factors, and factors related to lupus itself. Despite knowledge of this accelerated cardiac risk, evaluation of traditional risk factors has been sub-par. We propose that lupus patients be evaluated by preventive cardiologists and have access to their expertise and resources. In addition to nephrologists and dermatologists, preventive cardiologists should be an integral part of the care of patients with lupus.

Basic Science for the Clinician 44

There has been a sea change in our understanding of atherosclerosis. We have come a long way from the days where eating too much fat and not getting enough exercise and having the wrong genetic background was thought to be the entire story. A few years ago, the cardiologists began to embrace inflammation as a possible pathogenetic mechanism and from that came high-sensitivity C-reactive protein testing for just about everyone. Chronic systemic inflammation became an area of interest. We have learned that it is more than just corticosteroid use that causes accelerated atherosclerosis in our rheumatoid and lupus patients. Even C-reactive protein may be a pathogenetic player, not only a diagnostic clue. Oxidized phospholipids and the cells that recognize them may be crucial in the evolution of the atherosclerotic plaque. Statins may be useful in suppressing inflammation, not only in suppressing cholesterol levels. And now even cardiologists are thinking about immune mechanisms! A strange world, but the beneficiaries of going through this looking glass will be our patients. A true understanding of this seems to have required a most circuitous route-sometimes you have to leave for a long journey before you can return and really see home for the first time.

Oxidation hypothesis of atherogenesis: HDL inflammatory index and apolipoprotein A-I mimetic peptides

Coronary heart disease is the leading cause of death in the USA and worldwide. Optimizing the ratio and levels of low- and high-density lipoproteins (HDLs) has been a major focus of treatments in preventing atherosclerosis. While these therapies have made significant contributions in reducing heart disease, many patients with normal lipid levels still continue to have significant coronary heart disease and crippling cardiac events. Recent research has brought to light the fact that HDL, widely touted to be protective against atherosclerosis, can actually promote atherogenesis in certain conditions. Disruption of anti-inflammatory properties of HDL may result in atherosclerosis in the presence of decreased, increased or unchanged serum HDL-cholesterol levels. The ability of HDL to prevent or promote atherogenesis can be assessed using a parameter termed the HDL inflammatory index. The next generation of emerging therapeutics, such as apolipoprotein A-I mimetic peptides, will be aimed at improving the anti-inflammatory property of HDL and thus further reducing the incidence of coronary heart disease.

Patients with early rheumatoid arthritis exhibit elevated autoantibody titers against mildly oxidized low-density lipoprotein and exhibit decreased activity of the lipoprotein-associated phospholipase A2

Rheumatoid arthritis is a chronic inflammatory disease, associated with an excess of cardiovascular morbidity and mortality due to accelerated atherosclerosis. Oxidized low-density lipoprotein (oxLDL), the antibodies against oxLDL and the lipoprotein-associated phospholipase A₂ (Lp-PLA₂) may play important roles in inflammation and atherosclerosis. We investigated the plasma levels of oxLDL and Lp-PLA₂ activity as well as the autoantibody titers against mildly oxLDL in patients with early rheumatoid arthritis (ERA). The long-term effects of immunointervention on these parameters in patients with active disease were also determined. Fifty-eight ERA patients who met the American College of Rheumatology criteria were included in the study. Patients were treated with methotrexate and prednisone. Sixty-three apparently healthy volunteers also participated in the study and served as controls. Three different types of mildly oxLDL were prepared at the end of the lag, propagation and decomposition phases of oxidation. The serum autoantibody titers of the IgG type against all types of oxLDL were determined by an ELISA method. The plasma levels of oxLDL and the Lp-PLA₂ activity were determined by an ELISA method and by the trichloroacetic acid precipitation procedure, respectively. At baseline, ERA patients exhibited elevated autoantibody titers against all types of mildly oxLDL as well as low activity of the total plasma Lp-PLA₂ and the Lp-PLA₂ associated with the high-density lipoprotein, compared with controls. Multivariate regression analysis showed that the elevated autoantibody titers towards oxLDL at the end of the decomposition phase of oxidation and the low plasma Lp-PLA₂ activity are independently associated with ERA. After immunointervention autoantibody titers against all types of oxLDL were decreased in parallel to the increase in high-density lipoprotein-cholesterol and high-density lipoprotein-Lp-PLA₂ activity. We conclude that elevated autoantibody titers against oxLDL at the end of the decomposition phase of oxidation and low plasma Lp-PLA₂ activity are feature characteristics of patients with ERA, suggesting an important role of these parameters in the pathophysiology of ERA as well as in the accelerated atherosclerosis observed in these patients.

The pathogenesis of atherosclerosis in autoimmune rheumatic diseases: Roles of inflammation and dyslipidemia

As patients with autoimmune rheumatic diseases live longer due to improved therapies and preventive measures, death and disability from atherosclerosis, particularly myocardial infarcts, are increasing. The relative risks for atherosclerosis vary from approximately 1.6 in ankylosing spondylitis and psoriatic arthritis to 3.0 in rheumatoid arthritis (RA), and 6.0 in systemic lupus erythematosus (SLE). Increased risks are found when analyzed by atherosclerotic events, causes of death, or surrogate measures of atherosclerosis, such as carotid artery plaque, intimal-media thickness, or coronary artery calcification. At all ages among adults, atherosclerosis is increased in patients with SLE or RA compared to healthy controls. For example, in women with SLE under the age of 40 years, approximately 13% have carotid plaque compared to 2% of controls; over age 59 the percentages are 71 and 45, respectively. For patients with RA, prevalence is 7% under the age of 40 in patients compared to zero in controls; over 59 years the prevalences are 80% and 44%, respectively. In this review we will discuss the mechanisms involved as well as an overview of the natural history in pathobiology.