Reduced progression of bone erosion in cytomegalovirus seropositive rheumatoid arthritis patients.

BACKGROUND: Human cytomegalovirus (HCMV) seropositivity has been associated with higher inflammation during rheumatoid arthritis (RA). However, no data are available on the impact of HCMV seropositivity on bone erosion progression during RA. METHODS: We selected 487 individuals of ESPOIR cohort who fulfilled the 2010 ACR/EULAR criteria for RA. HCMV serology for these patients was determined using Architect CMV IgG assay. Baseline and 1-year central X-ray reading using modified Total Sharp Score (mTSS), Erosion Sharp Score, and joint space narrowing Sharp score were used to quantify structural damage progression. We performed univariate and multivariate analyses to investigate the association between HCMV status and bone erosion progression. RESULTS: We analyzed 273 HCMV seropositive (HCMV+) and 214 HCMV seronegative (HCMV-) RA patients. At inclusion, HCMV+ patients were less frequently ACPA+ (49.8% versus 58.9%, p < 0.0465) and had a higher DAS28-ESR (5.55 ± 1.24 versus 5.20 ± 1.14, p < 0.0013) in comparison with HCMV-. At 1 year, bone erosion progression (delta erosion Sharp score > 1 point) was lower in HCMV+ patients (16.1% versus 25.2%, p = 0.0128) in comparison with HCMV-. HCMV+ status remained independently associated with lower bone erosion progression in multivariate analysis. CONCLUSIONS: Our findings suggest that, independently of other confounding factors, HCMV seropositivity is associated with a lower progression of bone erosion during RA.

Novel model of placental tissue explants infected by cytomegalovirus reveals different permissiveness in early and term placentae and inhibition of indoleamine 2,3-dioxygenase activity.

Human cytomegalovirus (HCMV) is the most common cause of viral intrauterine infection. Placental infection suggests hematogenous spread and permissiveness may vary according to the age of pregnancy. We set up and investigate permissivity of early and term placenta to HCMV with an ex vivo model of placental histocultures and evaluate the activity profile of IDO. Fourteen first trimester placentae were obtained following elective abortion and twelve term placentae after elective caesarean section. Fresh placental chorionic villi were isolated, washed and distributed on collagen sponge gels after overnight incubation with the virus. The culture medium was collected and fresh medium renewed regularly. Histology and immunohistochemistry showed preserved villous integrity in cultured placental histocultures. Infection could be seen in tissue sections of both early and term placentae, although early placentae were more permissive. Indoleamine 2,3-dioxygenase (IDO) is highly expressed in the placenta and is known to prevent maternal immune rejection. Constitutive IDO activity was higher in early, compared to term placentae and HCMV infection inhibited IDO activity in early placentae. IFN-γ-induced IDO activity was suppressed by HCMV in both early and term placentae. Our work shows a novel method of placenta organ culture. Our findings suggest that HCMV infects early placentae more strongly than term placentae. Early placental dysfunction through the inhibition of IDO activity may reveal a possible mechanism for miscarriages.

Cytosolic phospholipase A2α gene silencing in the myeloid lineage alters development of Th1 responses and reduces disease severity in collagen-induced arthritis.

OBJECTIVE: Several lines of evidence implicate cytosolic phospholipase A(2)α (cPLA(2)α) as a critical enzyme in inflammatory disorders, including rheumatoid arthritis. Since cells from the myeloid compartment regulate local and systemic disease pathogenesis, the present study was undertaken to examine the effect of cPLA(2)α inhibition in experimental arthritis, using a delivery system tailored to target monocyte functions by RNA interference (RNAi). METHODS: Mice with collagen-induced arthritis (CIA) were injected intravenously with an anti-cPLA(2)α small interfering RNA (siRNA) sequence (siPLA2) formulated as lipoplexes with the RPR209120/DOPE cationic liposome and a carrier DNA. The clinical course of joint inflammation was assessed, and the immunologic balance was analyzed by measuring T helper cell frequencies and cytokine expression. Biodistribution studies of siRNA were also performed. RESULTS: Weekly systemic injection of siPLA2 lipoplexes significantly reduced the incidence and severity of CIA, in both preventive and curative settings, as compared with findings in control animals. Histologic scores for inflammation and cartilage damage were reduced. The clinical effect was associated with local inhibition of tumor necrosis factor α secretion and lower cPLA(2)α expression and activity. The siPLA2 lipoplexes enabled triggering of in vivo RNAi-mediated gene silencing of cPLA(2)α in CD11b+ cells recovered from the spleen. While the treatment had no effect on anti-type II collagen (anti-CII) antibodies, CII-specific T helper cells producing interferon-γ, but not interleukin-17, in draining lymph node cells were decreased. CONCLUSION: Our findings indicate that systemic RNAi-mediated cPLA(2)α gene silencing in CD11b+ cells is effective in the treatment of CIA, and Th1 suppression is one of the potential underlying mechanisms, whereas Th17 suppression is not.

A PCSK9 variant and familial combined hyperlipidaemia.

BACKGROUND: Our discovery in 2003 of the first mutations of PCSK9 gene causing autosomal dominant hypercholesterolaemia (ADH) shed light on an unknown factor that strongly influences the level of circulating low density lipoprotein cholesterol (LDL-C). PCSK9 gain of function mutations cause hypercholesterolaemia by a reduction of LDL receptor levels, while PCSK9 loss of function variants are associated with a reduction of LDL-C values and a decreased risk of coronary heart disease. METHODS AND RESULTS: We report an insertion of two leucines (p.L21tri also designated p.L15_L16ins2L) in the leucine stretch of the signal peptide of PCSK9 that is found in two of 25 families with familial combined hyperlipidaemia (FCHL). This mutant is associated with high total cholesterol and LDL-C values in these families and is found also in a patient with familial hypercholesterolaemia and her father. CONCLUSION: PCSK9 variants might contribute to FCHL phenotype and are to be taken into consideration in the study of this complex and multigenic disease with other genes implicated in dyslipidaemia.

Biochemical and bioimaging markers for risk assessment and diagnosis in major cardiovascular diseases: a road to integration of complementary diagnostic tools.

This report from the first International Course on Integrated Biomarkers, Biochemical and Bioimaging Endpoints in Cardiovascular Diagnosis, Prevention, Therapy and Drug Development provides the basis for optimizing diagnostic, prognostic and therapeutic information in four areas of cardiovascular medicine: primary prevention of cardiovascular diseases, acute coronary syndromes, heart failure and stroke. Risk stratification and treatment strategies can be refined and enhanced through integration of bioimaging and biochemical markers to characterize sub-clinical and clinical atherosclerosis. For the integrative approach to be useful, each of the biomarkers must be validated and cost-effective. Clinical decision is the primary level of integration and is based on clinical evaluation and the use of a combination of bioimaging and biochemical markers. The decision to initiate preventive or therapeutic intervention must take into account the factors affecting the levels of expression of the biomarker and the potential input the biomarker has on metabolic processes or modulation of other biomarkers. The optimal approach to intervention must take into consideration the risk-benefit and cost-effectiveness ratios.

Cardioprotective and other emerging effects of statins.

The lipid-lowering properties of statins are accompanied by a number of other cardioprotective effects. These 'pleiotropic' actions affect almost the entire process of atherogenesis, from initial endothelial injury to the moment of plaque rupture and thrombosis. This paper discusses the nonlipid-lowering effects of statins that affect the initiation, progression, regression and repair of atherosclerosis lesions, as well as factors that affect plaque instability. The emergent anti-inflammatory, antioxidant and immunomodulatory properties of statins are extensive and diverse. Many of these properties, which are independent of cholesterol synthesis inhibition, help to reduce the ischaemic burden on the cardiovascular system. In addition, the immunomodulatory properties of statins may provide new indications for these agents in the treatment of autoimmune diseases.

IE1-pp65 recombinant protein from human CMV combined with a nanoparticulate carrier, SMBV, as a potential source for the development of anti-human CMV adoptive immunotherapy.

BACKGROUND: Human cytomegalovirus (HCMV) infection and reactivation following allogeneic bone marrow transplantation is a major source of complications in grafted patients including pneumonitis, graft rejection and even death. Adoptive immunotherapy consisting in transfer of CD4(+) and CD8(+) T cells directed against HCMV has proved its worth. Nevertheless, established procedures have to be improved in terms of safety and waiting period required to obtain specific T cells. METHODS: As an alternative to infectious virus used in current strategies, we purified a recombinant protein IE1-pp65 resulting from the fusion of the regulatory IE1 and matrix pp65 proteins, both known as the major targets of the overall anti-HCMV T cell response. Based on our previous data demonstrating its use for in vitro stimulation and expansion of anti-HCMV CD4(+) and CD8(+) T cells (Vaz-Santiago et al, 2001, J.Virol, 75:7840-47) from peripheral blood mononuclear cells (PBMC) of seropositive donors, we planned to improve its in vitro immunogenicity through association with a nanoparticulate carrier, SMBV. RESULTS: We demonstrated that using of SMBV/IE1-pp65 formulation allowed to potentiate in vitro activation of T cells and to expand more CD8(+) T cells than with soluble IE1-pp65, following stimulation of PBMC. DISCUSSION: These data suggest the use of SMBV/IE1-pp65 formulation as a potential source of antigen for efficient T cells expansion in the development of safe anti-HCMV immunotherapy.

Moderate intake of n-3 fatty acids is associated with stable erythrocyte resistance to oxidative stress in hypertriglyceridemic subjects.

BACKGROUND: The important triacylglycerol-lowering capacity of n-3 fatty acids is counterbalanced by their inherent sensitivity to oxidation. Inconsistent results about the latter have been reported in hypertriglyceridemic individuals. After incorporation into cell membranes, n-3 fatty acids may alter membrane-related functions. In view of the distinct composition of hypertriglyceridemic membranes and the prooxidant status in this condition, it can be surmised that cell enrichment with the oxidizable n-3 fatty acids will be associated with an increased hemolytic process. OBJECTIVE: We sought to evaluate the effect of fish oil consumption on n-3 fatty acid incorporation into erythrocyte membranes and subsequent ex vivo oxidative-stress-induced hemolysis in normotriglyceridemic and hypertriglyceridemic subjects. DESIGN: Sixteen normotriglyceridemic and 12 hypertriglyceridemic subjects were given 6 g fish oil/d for 8 wk. Blood samples were collected before and 4 and 8 wk after treatment. Resistance to 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced hemolysis was assayed in fresh erythrocyte suspensions, and erythrocyte samples were stored at -70 degrees C for later analysis of cholesterol, hemoglobin, fatty acids, vitamin E, and glutathione peroxidase activity. RESULTS: Fish oil supplementation induced n-3 fatty acid incorporation in normotriglyceridemic and hypertriglyceridemic erythrocyte membranes without decreasing their resistance to AAPH. n-3 Fatty acids significantly protected normotriglyceridemic but not hypertriglyceridemic erythrocytes against hemolysis. In normotriglyceridemic subjects only, the higher resistance to hemolysis correlated with changes in cell vitamin E. CONCLUSION: Although they exhibit a high susceptibility to oxidation, n-3 fatty acids may preserve membrane integrity and represent an added benefit in the treatment of hypertriglyceridemic patients.

Ex vivo stimulation and expansion of both CD4(+) and CD8(+) T cells from peripheral blood mononuclear cells of human cytomegalovirus-seropositive blood donors by using a soluble recombinant chimeric protein, IE1-pp65.

The transfer of anti-human cytomegalovirus (HCMV) effector T cells to allogeneic bone marrow recipients results in protection from HCMV disease associated with transplantation, suggesting the direct control of CMV replication by T cells. IE1 and pp65 proteins, both targets of CD4(+) and CD8(+) T cells, are considered the best candidates for immunotherapy and vaccine design against HCMV. In this report, we describe the purification of a 165-kDa chimeric protein, IE1-pp65, and its use for in vitro stimulation and expansion of anti-HCMV CD4(+) and CD8(+) T cells from peripheral blood mononuclear cells (PBMC) of HCMV-seropositive donors. We demonstrate that an important proportion of anti-HCMV CD4(+) T cells was directed against IE1-pp65 in HCMV-seropositive donors and that the protein induced activation of HLA-DR3-restricted anti-IE1 CD4(+) T-cell clones, as assessed by gamma interferon (IFN-gamma) secretion and cytotoxicity. Moreover, soluble IE1-pp65 stimulated and expanded anti-pp65 CD8(+) T cells from PBMC of HLA-A2, HLA-B35, and HLA-B7 HCMV-seropositive blood donors, as demonstrated by cytotoxicity, intracellular IFN-gamma labeling, and quantitation of peptide-specific CD8(+) cells using an HLA-A2-peptide tetramer and staining of intracellular IFN-gamma. These results suggest that soluble IE1-pp65 may provide an alternative to infectious viruses used in current adoptive strategies of immunotherapy.

Interaction of lecithin:cholesterol acyltransferase (LCAT).alpha 2-macroglobulin complex with low density lipoprotein receptor-related protein (LRP). Evidence for an alpha 2-macroglobulin/LRP receptor-mediated system participating in LCAT clearance.

The reaction of lecithin:cholesterol acyltransferase (LCAT) with high density lipoproteins (HDL) is of critical importance in reverse cholesterol transport, but the structural and functional pathways involved in the regulation of LCAT have not been established. We present evidence for the direct binding of LCAT to alpha(2)-macroglobulin (alpha(2)M) in human plasma to form a complex 18.5 nm in diameter. Forty percent of plasma LCAT-HDL was associated with alpha(2)M; moreover, most of the LCAT in cerebrospinal fluid and in the medium of cultured human hepatoma cell line was associated with alpha(2)M. Purified recombinant human LCAT (rLCAT) labeled with (125)I bound to native and methylamine-activated alpha(2)M (alpha(2)M-MA) in vitro in a time- and concentration-dependent manner, and this binding did not depend on the presence of lipid. rLCAT bound to alpha(2)M-MA with greater affinity than to alpha(2)M. Furthermore, rLCAT did not activate alpha(2)M as phosphatidylcholine-specific phospholipase C does. Reconstituted HDL particles (LpA-I) inhibited the binding of rLCAT to alpha(2)M more efficiently than native HDL(3) did. LCAT associated with alpha(2)M was enzymatically inactive under both endogenous and exogenous assay conditions. Purified rLCAT alone did not bind to low density lipoprotein receptor-related protein (LRP) as lipoprotein lipase (LPL) does; however, when rLCAT was combined with alpha(2)M-MA to form a complex, binding, internalization, and degradation of rLCAT took place in LRP-expressing cells (LRP (+/+)) but not in cells deficient in LRP (LRP (-/-)). It is concluded that the binding of LCAT to alpha(2)M inhibits its enzymatic activity. Furthermore, the finding supports the possibility that the LRP receptor can act in vivo to mediate clearance of the LCAT-alpha(2)M complex and may significantly influence the bioavailability of LCAT.

Efficacy and short-term safety of a new ACAT inhibitor, avasimibe, on lipids, lipoproteins, and apolipoproteins, in patients with combined hyperlipidemia.

Although acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors have been shown to reduce lipid levels in several animal models, the safety and lipid modifying activity of any single agent in this class has not been demonstrated in humans. The safety and efficacy of avasimibe (CI-1011), a new, unique, wholly synthetic ACAT inhibitor, was evaluated in the treatment of 130 men and women with combined hyperlipidemia and hypoalphalipoproteinemia (low levels of high-density lipoprotein cholesterol [HDL-C]). Following an 8-week placebo and dietary-controlled baseline period, patients were randomly assigned to double-blind treatment with placebo, 50, 125, 250, or 500 mg avasimibe administered as capsules once daily for 8 weeks. At all evaluated doses, avasimibe treatment resulted in prompt and significant reductions (P<0.05) in plasma levels of total triglycerides (TG) and very low-density lipoprotein cholesterol (VLDL-C) with mean reductions of up to 23% and 30% respectively, apparently independent of dose. No statistically significant changes in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), HDL-C or apolipoprotein (apo) B were detected. ApoAI levels were also unchanged on all doses of avasimibe apart from the 500 mg dosage, which was associated with a significant decrease in plasma apoAI. The relevance of this latter finding in only one dosage group is not known. All doses of avasimibe were well tolerated with no resulting significant abnormalities of biochemical, hematological, or clinical parameters.

Identification of a gamma-interferon-responsive element in the promoter of the human macrophage scavenger receptor A gene.

In the present study, we demonstrate gamma-interferon (gamma-IFN)-inducible scavenger receptor A (SR-A) mRNA expression during the early stages of THP-1 and blood monocyte differentiation. Predominant induction of SR-A type II mRNA parallels the increased accumulation of cholesteryl esters under these conditions. A potential signal transducer and activator of transcription (STAT1) binding site (gamma-interferon activation site) in the SR-A promoter demonstrates gamma-IFN-inducible DNA binding activity and is most likely responsible for the gamma-IFN-dependent expression of an SR-A promoter-luciferase fusion construct. In contrast, gamma-IFN inhibits SR-A expression in mature macrophages as well as after prolonged gamma-IFN incubation of THP-1 monocytes. Taken together, these results demonstrate opposite effects of gamma-IFN on SR-A expression and activity during the early versus late stages of monocyte maturation. gamma-IFN-induced STAT1 activation, leading to increased SR-A expression, could therefore play an important role in the initial steps of foam cell formation and xanthomatosis.

[Mechanisms of action of statins and their pleiotropic effects]. / Mécanismes d'action des statines et leurs effets pléiotropes.

This brief review and update considers a few aspects of the mechanisms of action of statins, especially those related to some of the pleiotropic effects that have clinical relevance. The beneficial effect on endothelial dysfunction is a class effect that is related not only to the lowering of plasma LDL-cholesterol but also to a direct effect on nitric oxide (NO) production. It is an early and sustained effect, linked to oxidative processes, that deserves particular attention since endothelial dysfunction is intimately linked to atherogenesis. Awareness of the anti-inflammatory effect came about following the observation that statin administration in humans reduces markers of inflammation in the circulation. The importance of these observations is ascribable to the fact that atherosclerosis is an inflammatory disease, that the inflammatory process in a coronary artery is now measurable in vivo in humans, that it contributes to the progression and the destabilization of the plaque, and also, because statins exert a number of effects that tend to stabilize it. Statins, and particularly lipophilic statins, in general inhibit cell proliferation, seemingly by multifaceted mechanisms. These include inhibition of cell cycle progression, induction of apoptosis, reduction of cyclooxygenase-2 activity and an enhancement of angiogenesis. At the center of these mechanisms stands the ability to inhibit G protein prenylation through a reduction of farnesylation and geranylgeranylation. This effect has been used to show that statins are anticarcinogenic in vitro and in animals. The clinical relevance of such a property remains to be proven but is supported by promising observations in animals and in humans which are detailed in this review. Finally, the ability of lipophilic statins to increase the production of bone morphogenetic protein-2 (BMP-2), and to enhance osteogenesis in animals combined with the results of several clinical studies should stimulate physicians to seriously consider an eventual indication of statins for the treatment of osteoporosis.

Lipoprotein distribution of apolipoprotein C-III and its relationship to the presence in plasma of triglyceride-rich remnant lipoproteins.

The distribution of apolipoprotein C-III (apoC-III) between high-density lipoprotein (HDL) and apoB-containing lipoproteins has been used in lipid-lowering angiographic trials to establish a link between impaired triglyceride (TG)-rich lipoprotein (TRL) metabolism and the progression of coronary artery disease. To investigate the extent to which plasma lipoprotein apoC-III levels reflect the presence in plasma of potentially atherogenic remnant lipoproteins, we studied 4 groups of subjects: (1) normolipidemic (NL, n = 10), (2) hypercholesterolemic (HC, type IIa, low-density lipoprotein cholesterol [LDL-C] > 3.4 mmol/L, n = 10), (3) hypertriglyceridemic (HTG, type IV, TG > 2.3 mmol/L, n = 10), and (4) combined hyperlipidemic (CHL, type IIb, TG > 2.3 mmol/L, LDL-C > 3.4 mmol/L, n = 10). The apoC-III level was measured in plasma lipoproteins separated either by density (ultracentrifugation) or by size (fast protein liquid chromatography [FPLC]), and was compared with 4 parameters reflecting remnant lipoprotein levels (ie, very-low-density lipoprotein cholesterol [VLDL-C], intermediate-density lipoprotein cholesterol [IDL-C], remnant-like particle cholesterol [RLP-C], and intermediate-sized lipoprotein [ISL] apoE). Our results demonstrate that (1) increased amounts of apoC-III associated with plasma VLDL, TRL, or apoB-containing lipoproteins (LpB), as well as increased levels of TRL remnant lipoproteins, are a characteristic of HTG patients rather than patients with increased LDL, and (2) plasma levels of apoC-III in VLDL, TRL, or LpB, as well as the HDL apoC-III to LpB apoC-III ratios, are strongly correlated with circulating levels of TRL, although these apoC-II parameters more closely reflect the balance between TRL TG production and lipolysis than the extent of plasma TRL remnant accumulation.

Impact of apoE deficiency on oxidative insults and antioxidant levels in the brain.

Apolipoprotein E (apoE) is a lipid transport molecule, which has been linked to the pathogenesis of Alzheimer's disease. Recently we have demonstrated that the oxidative insults in hippocampus from AD patients were dependent on the apoE genotype. Interestingly, apoE protein concentration in hippocampus follows a genotype-dependent gradient with the lowest level occurring in varepsilon4 allele carrier. We raised the possibility that, in the hippocampus, the apoE level affects the oxidant/antioxidant balance. Here, we have examined in the apoE-deficient mouse the oxidant/antioxidant status in hippocampus and in frontal cortex from APOE-KO and wild-type mice at 3 and 13 months. We provided evidence that, in the hippocampus, the absence of apoE has a clear impact on the oxidant/antioxidant status. Endogenous level of thiobarbituric acid-reactive substances (TBARS) was found to be markedly elevated whereas level of alpha-tocopherol was decreased in APOE-deficient mice at 3 and 13 months. Superoxide dismutase activities were also lower in APOE-deficient mice at 13 months. Taken together, these data indicate that the steady state level of apoE may influence, to a certain extent, the balance between oxidants and antioxidants in hippocampus.

Advances in lipid-lowering therapy in atherosclerosis.

The accrued evidence that lipid-lowering therapy limits the progression of atherosclerosis and reduces CAD events is overwhelming. The focus has been on LDL-C reduction with statins, but recent evidence also stresses the importance of raising HDL-C and reducing triglyceride-rich lipoproteins (TRL). Treatment should take into account the type of dyslipidemia, combination therapy, drug interactions and pleiotropic effects of drugs (multiple effects in different systems). Statins and fibrates are the most widely prescribed. Fibrates have a major impact on plasma TRL and HDL-C levels. They enhance lipoprotein lipase, apoAI and apoAII transcription and reduce that of apoCIII. The discovery that their multiple actions are in large part mediated by the PPAR alpha pathway is a breakthrough. Fibrates also lower plasma fibrinogen and plasma viscosity but their ability to inhibit smooth muscle cell activation is one of their most promising pleiotropic effects. Statins are safe and potent LDL-C-lowering agents but also lower TRL and raise HDL. Their pleiotropic effects are numerous, and include vasodilatory, anti-thrombotic, antioxidant, anti-proliferative, anti-inflammatory and plaque stabilizing properties. Many findings make a case for their early use in CAD to improve myocardial perfusion after a myocardial infarction, and they are indicated in heart transplant recipients to improve survival and reduce graft rejection. Fibrates and statins have complementary lipid modifying and pleiotropic effects so that their combination, carried out with caution to avoid potential untoward effects, should provide the highest cardiovascular benefit. This hypothesis is currently being tested in the Lipid in Diabetes Study (LDS), an outcome trial comparing monotherapy with fenofibrate and cerivastatin to combination therapy conducted in England.

Involvement of oxysterols and lysophosphatidylcholine in the oxidized LDL-induced impairment of serum albumin synthesis by HEPG2 cells.

Oxidized low density lipoproteins (Ox-LDLs) are increasingly thought to be a key element in atherogenesis. We have previously reported that serum albumin has important antioxidant properties and that a reduced synthesis of albumin may represent a crucial point in the overall antioxidant defense. In the present work, we aimed at determining whether Ox-LDL could modulate albumin synthesis in cultured human hepatocytes (HepG2 cells). With the use of enzyme immunoassay and radiolabeled leucine incorporation followed by specific immunoprecipitation, Ox-LDL was found to lead to a dose-dependent decrease in albumin secretion. Moreover, the protein synthesis and mRNA levels were decreased in the presence of Ox-LDL, as assessed by Northern blot analysis. Because oxysterols and lysophospholipids are key components of Ox-LDL, we tested the effects of oxysterols (7-ketocholesterol and 25-hydroxycholesterol) and lysophosphatidylcholine on albumin secretion and expression. In our experimental conditions, we found that incubations with oxysterols or lysophosphatidylcholine at pathophysiological concentrations similar to those measured in Ox-LDLs reproduced the above-mentioned inhibitory effects on albumin synthesis. On the basis of our in vitro data, we propose that this newly described biological effect of Ox-LDL might partly explain the findings of epidemiological studies indicating that reduced levels of serum albumin are associated with increased mortality.

Remnant-like particle cholesterol and triglyceride levels of hypertriglyceridemic patients in the fed and fasted state.

Potentially atherogenic triglyceride-rich lipoprotein (TRL) remnants can be isolated and quantitated as remnant-like particles (RLP), using an immunoaffinity gel containing specific anti-human apolipoprotein A-I (apoA-I) and apoB-100 monoclonal antibodies. The aim of the present study was to determine the relationship between postprandial changes in RLP levels and changes in total serum triglyceride (TG) in patients with different forms of hypertriglyceridemia (HTG). Three groups of patients were selected, having similarly elevated serum TG levels: a) HTG with TRL remnant accumulation (i.e., type III patients, n = 15, TG: 3.8 +/- 0.2 mm), b) HTG with increased LDL (i.e., type IIb patients, n = 15, TG: 3.7 +/- 0.2 mm), and c) HTG without evidence of remnant or LDL accumulation (i.e., type IV patients, n = 15, TG: 3.9 +/- 0.3 mm). Ingestion of a 45-g fat meal caused a significant increase in serum TG (30;-50%) in all patients. Mean serum TG levels of the three groups were not significantly different at 4 or 6 h after the meal. RLP cholesterol (C) and TG levels increased after the meal in all patients, but these postprandial increases were also not significantly different among groups. Type III patients had significantly higher (P < 0.01) levels of RLP-C and RLP-apoE in the fasted and fed state, and also had significantly higher RLP-C-to-serum TG ratios (P < 0.001) compared with the other groups. These results indicate that 1) RLP-C and RLP-TG levels are significantly increased in the fed versus fasted state in patients with elevated fasting TG levels; 2) patients with different forms of HTG, but similar TG levels, have similar postprandial increases in RLP-C and RLP-TG; and 3) type III patients have significantly elevated levels of RLP-C and RLP-apoE in both the fed and fasted state.

Plasma kinetics of apoC-III and apoE in normolipidemic and hypertriglyceridemic subjects.

Apolipoprotein (apo) C-III and apoE play a central role in controlling the plasma metabolism of triglyceride-rich lipoproteins (TRL). We have investigated the plasma kinetics of total, very low density lipoprotein (VLDL) and high density lipoprotein (HDL) apoC-III and apoE in normolipidemic (NL) (n = 5), hypertriglyceridemic (HTG, n = 5), and Type III hyperlipoproteinemic (n = 2) individuals. Apolipoprotein kinetics were investigated using a primed constant (12 h) infusion of deuterium-labeled leucine. HTG and Type III patients had reduced rates of VLDL apoB-100 catabolism and no evidence of VLDL apoB-100 overproduction. Elevated (3- to 12-fold) total plasma and VLDL apoC-III levels in HTG and Type III patients, although associated with reduced apoC-III catabolism (i.e., increased residence times (RTs)), were mainly due to increased apoC-III production (plasma apoC-III transport rates (TRs, mean +/- SEM): (NL) 2.05 +/- 0.22 (HTG) 4.90 +/- 0.81 (P < 0.01), and (Type III) 8.78 mg. kg(-)(1). d(-)(1); VLDL apoC-III TRs: (NL) 1.35 +/- 0. 23 (HTG) 5.35 +/- 0.85 (P < 0.01), and (Type III) 7.40 mg. kg(-)(1). d(-)(1)). Elevated total plasma and VLDL apoE levels in HTG (2- and 6-fold, respectively) and in Type III (9- and 43-fold) patients were associated with increased VLDL apoE RTs (0.21 +/- 0.02, 0.46 +/- 0. 05 (P < 0.01), and 1.21 days, NL vs. HTG vs. Type III, respectively), as well as significantly increased apoE TRs (plasma: (NL) 2.94 +/- 0.78 (HTG) 5.80 +/- 0.59 (P < 0.01) and (Type III) 11.80 mg. kg(-)(1). d(-)(1); VLDL: (NL) 1.59 +/- 0.18 (HTG) 4.52 +/- 0.61 (P < 0.01) and (Type III) 11.95 mg. kg(-)(1). d(-)(1)). These results demonstrate that hypertriglyceridemic patients, having reduced VLDL apoB-100 catabolism (including patients with type III hyperlipoproteinemia) are characterized by overproduction of plasma and VLDL apoC-III and apoE.

Oxidative insults are associated with apolipoprotein E genotype in Alzheimer's disease brain.

The epsilon4 allele of the apolipoprotein E gene (APOE) is associated with sporadic and familial late-onset Alzheimer's disease (AD). Oxidative stress is believed to play an important role in neuronal dysfunction and cell death in AD. We now provide evidence that in the hippocampus of AD, the level of thiobarbituric acid-reactive substances (TBARS) and the APOE genotype are linked. Within AD cases, the levels of TBARS were found to be higher among epsilon4 carriers while the apoE protein concentrations were lower. The relationship between the levels of TBARS and apoE proteins was corroborated by the results from the APOE-deficient mice, in which the levels of TBARS were higher than those in wild-type mice. Among AD cases, tissues from patients with the epsilon4 allele of APOE displayed lower activities of catalase and glutathione peroxidase and lower concentration of glutathione than tissues from patients homozygous for the epsilon3 allele of APOE. Together these data demonstrate that, in AD, the epsilon4 allele of APOE is associated with higher oxidative insults.