LPS-induced cytokine production and expression of beta2-integrins and CD14 by peripheral blood mononuclear cells of patients with homozygous familial hypercholesterolemia

Beyond cholesterol-pleiotropic effects of lipoprotein apheresis

Cardiovascular disease is a leading cause of mortality worldwide, which is caused mainly by atherosclerosis, a chronic inflammatory disease of blood vessels. Therefore, atherosclerosis represents a complex disorder, which induces damage or imbalance on different levels: for example, genes, cytokines, lipoproteins, cells, vessels, and organs. Lipoprotein apheresis (LA) is a well-established extracorporeal treatment of severe hyperlipoproteinemia. In addition, LA may have simultaneously crucial effects on many other atherogenic factors during the treatments, for example, as vascular inflammation, rheology, mobilization of adult stem cells and gene expressions in blood or endothelial cells, which will be discussed in this short review. In addition, stable microRNAs besides tissues also appear in extracellular compartments, for example, vessels, involved in atherosclerotic processes, were found to be reduced by LA treatments. In summary, LA represents a complex therapeutic procedure, that provides an ideal tool for the treatment of complex disorders such as atherosclerosis.

Innate and Acquired Cellular Immunity in Children with Familial Hypercholesterolemia Treated with Simvastatin

The aim of this cross-sectional study was to assess the influence of simvastatin treatment in children with familial hypercholesterolemia (FH) on parameters of cellular immunity. Twenty-six children with FH were included, of which thirteen were treated with 10 mg simvastatin for at least 26 weeks, and thirteen were age- and sex-matched with a low-cholesterol diet only. Total WBC count and lipid profile were measured. Flow cytometry was used to identify lymphocyte subsets and determine the expression of adhesion molecules (AM) and toll-like receptors (TLRs) on leukocytes. No differences were found in the basic values of peripheral blood count and subpopulations of lymphocytes between groups. The percentage of granulocytes with the expression of AM was higher in those treated with statins. The TLR-2 expression on granulocytes and monocytes showed higher values, whereas the TLR-4 expression was lower on lymphocytes and granulocytes in simvastatin-treated children. Treatment with simvastatin in children with FH is not associated with alterations in the amounts of granulocytes and monocytes. There is no association between statin treatment and the pattern of peripheral blood lymphocyte subpopulations. The role of AM and TLRs needs further investigation, given the effect of statins on the innate immunity may be important for their efficacy and safety during growth.

Apheresis-inducible cytokine pattern change in children with homozygous familial hypercholesterolemia

Familial hypercholesterolemia is a genetic disorder that leads to severe atherosclerosis related cardiovascular complications in young adults. Extracorporeal elimination is a method of LDL-lowering procedures effective in patients with homozygous or severe heterozygous FH utilized in cases. The recruitment of leucocytes into the arterial intima is dependent on a cascade of events mediated through a diverse family of adhesion molecules. Several pro-inflammatory adhesion molecules are cleared by various lipid apheresis methods. This study showed that, LDL-apheresis led to several changes in circulating inflammatory factors which induced antiinflammatory and antiatherogenic changes in the plasma profile in homozygous familial hypercholesterolemic patients.

Apheresis-inducible cytokine pattern change in severe, genetic dyslipidemias

OBJECTIVE

The effects of direct adsorption of lipids LDL-apheresis (DALILDL-a) on plasma cytokines in two Homozygous and heterozygous familial hypercholesterolemic (HozFH, HtzFH) and in four HyperLp(a)lipoproteinemic [HyperLp(a)] patients, were evaluated.

METHODS

Plasma, macrophage inflammatory proteins 1α (MIP-1α), macrophage inflammatory proteins 1β (MIP-1β), monocyte chemoattractant protein-1 (MCP-1), RANTES (Regulated upon Activation, Normal T-cell Expressed, and Secreted), granulocyte-colony stimulating factor (GCSF), granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin-1α (IL-1α), interleukin-1β (IL-1β), interleukin-2 (IL-2), interleukin-6 (IL-6), interferon-γ (IFN-γ), concentrations, were measured before and after LDL-a on three consecutive sessions for each patient.

RESULTS

MIP-1α was significantly reduced (P=0.05), while MIP-1β was significantly increased (P=0.05). Plasma MCP-1 was reduced, although not significantly, while RANTES was significantly increased (P=0.05). GCSF and GM-CSF were both significantly reduced (GM-CSF: P=0.05, GCSF: P=0.05, respectively). IL-1α level was significantly reduced (P=0.001). IL-1β, IL-6, and IFN-γ levels were significantly reduced in plasma after apheresis (IL-1β: P=0.001, IL-6: T1 P=0.001; T2 P=0.05, respectively, IFN-γ: P=0.001). IL-2 level in plasma was significantly reduced at T0, and T2, (P=0.001). However, IL-2 level showed a statistically significant increase at T1 (P=0.001). A significant correlation between IL-1α and IFN-γ was found: r=0.882 (P=0.001).

CONCLUSIONS

In this study LDL-a induced profound changes in several circulating cytokines and promoted anti-inflammatory and anti-atherogenic cytokine profile in plasma of patients with severe dyslipidemia, with pre-existing angiographically demonstrated Coronary heart disease (CHD), and aortic valvular disease (#=1) (AVD).

Lipid and low-density-lipoprotein apheresis. Effects on plasma inflammatory profile and on cytokine pattern in patients with severe dyslipidemia

Available evidence on the effects of therapeutic plasmapheresis (TP) techniques and in particular lipid- and LDL-apheresis (LDL-a) on plasmatic inflammatory mediators including cytokines were reviewed. Studies on this issue are not numerous. However, the review of existing evidence clearly suggests an active role of apheresis on the profile of inflammatory molecules and on cytokine pattern in plasma. These non-lipid-lowering effects can be defined to some extent pleiotropic or pleiotropic-equivalent. Although further studies are desirable, the data reported in this review confirm that lipid- and LDL-a not only show acute lipid-lowering and cholesterol-lowering effects, but also efficacy in reducing several proinflammatory peptides, including cytokines. This effect was not related apparently to lipids and lipoproteins reduction. Thus, TP (lipid- and LDL-a), commonly utilized in the treatment of severe genetically determined lipid disorders, unresponsive to hypolipidemic drugs, offers new possibilities of interpretation of its role in the mechanisms leading to the blockade of atherosclerotic lesion development and progression. The ability of TP on short-term to induce such a profound change in the plasmatic metabolic and inflammatory profiles must be kept in mind in the treatment of acute coronary syndromes, before and after interventions of coronary revascularization, and in the acute phase of cerebrovascular ischemia, at least in patients with severe dyslipidemia. Further studies are needed, in particular aimed at assessing if circulating cytokines may be downregulated by TP not only by direct removal, but through indirect effects on both gene translation and transcription perhaps via the cytokine receptor function.

Stronger in vitro phagocytosis by monocytes-macrophages is indicative of greater pathogen clearance and antibody levels in vivo

Monocytes-macrophages are crucial players in specific and nonspecific immune responses to protect organisms from invasion of bacteria or viruses. In this study, monocytes in circulation from 2 lines of Silky and Starbro chickens with different disease resistance were separated and cultured in vitro. After identification with acridine orange (AO), Giemsa staining, and CD14 immunostaining, monocytes-macrophages were used for adherence and phagocytosis test. The overall percentages of adherence of Silky monocytes was 1.5 times greater than that of Starbro (P < 0.01), which were 26.85% +/- 8.24% and 18.34% +/- 8.15%, respectively (mean +/- SD). The monocytes-macrophages phagocytic index, phagocytic product, and percentage of phagocytosis in Silkies were greater than in Star-bros, respectively. The difference of phagocytic index was significant (P < 0.05), that is, 3.70 +/- 1.75 and 1.97 +/- 0.31, respectively (mean +/- SD). Then, 20 Silkies were divided into 2 groups according to phagocytic index: high phagocytic index (HPI) group and low phagocytic index (LPI) group, to study the relationship between phagocytic activity in vitro and pathogen clearance. After being challenged against Salmonella Pullorum C79-13, the Silky birds with HPI produced a 3-fold greater level of specific antibodies compared with those with LPI (P < 0.01), 50.21 +/- 6.67 and 16.85 +/- 4.52, respectively (mean +/- SD). In contrast to LPI birds, HPI birds shed less Salmonella Pullorum bacteria (P < 0.05), that is, 168.98 x 10(8) +/- 294.74 x 10(8) compared to 385.40 x 10(8) +/- 399.94 x 10(8) (mean +/- SD), and the shedding peak of Salmonella Pullorum in the test span appeared 4 d earlier. These results indicated that phagocytosis of monocytes-macrophages had strong effects on antibody titer and bacteria shedding postchallenge, which could be used to predict the disease resistance in animals.

Ethnic and sex differences in circulating endotoxin levels: A novel marker of atherosclerotic and cardiovascular risk in a British multi-ethnic population

BACKGROUND

Circulating endotoxin levels are associated with atherosclerosis. Moreover, ethnic differences in pro-inflammatory markers may be associated with ethnic differences in atherosclerotic and cardiovascular (CVD) and coronary heart disease (CHD) risk.

OBJECTIVE AND METHODS

To investigate ethnic differences in circulating plasma endotoxin levels, its soluble receptor (sCD14), and high-sensitivity CRP (hs-CRP). 192 individuals, aged 40-59 years (61 white (30 women), 68 of African origin (33 women) and 63 South Asians (33 women)), free from coronary heart disease (CHD), stroke, CVD and diabetes were randomly selected from the UK 'Wandsworth Heart and Stroke Study'.

RESULTS

Age-adjusted endotoxin levels were lower in women than in men (p=0.002) and were highest in South Asians (13.3EU/mL [95% CI 12.0-14.7]) and lowest in individuals of African origin (10.1EU/mL [9.1-11.1]) than in whites (p for linear trend <0.001). Endotoxin levels were positively associated with waist, waist-hip ratio, total cholesterol, serum triglycerides and serum insulin levels and negatively associated with serum HDL-cholesterol. Serum hs-CRP and plasma sCD14 varied by ethnic group (p<0.001) but was not associated with endotoxin.

CONCLUSIONS

This study is the first to indicate a graded increase in endotoxin levels from black Africans to whites to South Asians, which is consistent with the ethnic difference in CHD risk. Whilst these findings support the concept that the innate immune system (IIS) may contribute significantly to the metabolic component underlying the development of CVD and CHD risk, further studies are required to see whether endotoxin levels are causally related to the development of CHD.

Chronic perivascular inoculation with Chlamydophila pneumoniae results in plaque formation in vivo

Hypercholesterolemic and normocholesterolemic rabbit models of chronic arterial Chlamydophila (Chlamydia) pneumoniae (CPN) inoculation were established and the role of both viable and inactivated bacteria was investigated in atherogenesis. A total of 29 rabbits were randomized to four groups. Groups A and B were fed a cholesterol-enriched diet, and groups C and D were fed a normal diet. Arterial segments of group A and C animals were inoculated in vivo using viable CPN chronically using repeated perivascular applications. Contralateral arteries were treated using heat-inactivated CPN. Group B and D animals were treated with repeated perivascular injections of bacterial lipopolysaccharide (LPS) and saline (control). Additional hypercholesterolemic rabbits were treated by repeated injections using viable and inactivated CPN, each controlled by saline injections. To compare the effects of this chronic inoculation model, additional animals received single injections of either viable CPN, inactivated CPN, LPS, or saline. Vascular tissues (n=162 treated arteries of 29 rabbits) were analyzed using morphometry at histology. CPN was detected by fluorescence-immunohistochemistry and nested polymerase chain reaction. Only in hypercholesterolemic, but not in normocholesterolemic rabbits, chronic perivascular infection of all bacterial components, viable and heat-inactivated CPN, as well as LPS resulted in a significant increase in atheromatous lesion formation (lesion area index: 0.23+/-0.08, 0.25+/-0.09, and 0.15+/-0.05) when compared to controls (lesion area index 0.01+/-0.01, P=0.002). CPN persisted in atheromatous lesions and vascular tissues. Single perivascular infection using CPN or inactivated CPN was not able to induce lesion formation (lesion area index: 0.03+/-0.03, 0.03+/-0.02 vs 0.03+/-0.02 after single saline inoculation, P=0.965). In conclusion, chronic vascular infection with CPN or CPN components acts as a cofactor requiring other major atherogenic stimuli, rather than as a causative agent.

LPS-Induced Release of IL-1β, IL-1Ra, IL-6, and TNF-αin Whole Blood from Patients with Familial Hypercholesterolemia: No Effect of Cholesterol-Lowering Treatment

Proinflammatory cytokines, such as interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha), are suggested to have an important role in the process of atherosclerosis. Patients with heterozygous familial hypercholesterolemia (FH) have a marked elevation in the plasma level of low-density lipoproteins (LDL), and they show early development of atherosclerosis. The aim of the present study was to test with a whole blood culture system if hyperlipoproteinemia is associated with increased cytokine production capacity in these patients and if treatment with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors influences this production capacity of blood cells, at both the protein and mRNA levels. The capacity of blood cells in a whole blood culture to produce IL-1beta, IL-6, TNF-alpha, IL-12, IL-18, and IL-1 receptor antagonist (IL-1Ra) in response to lipopolysaccharide (LPS) appeared to be similar for heterozygous FH patients and healthy volunteers. Furthermore, the capacity to produce IL-1beta, IL-6, and TNF-alpha in response to LPS was not modified by cholesterol synthesis inhibitors at the level of mRNA expression or at the level of release. On the other hand, the release of IL-1Ra was significantly increased after treatment with HMG-CoA reductase inhibitors, although only at the protein level. This suggests a possible beneficial anti-inflammatory role for this therapy.

Elevated serum levels of proinflammatory cytokines and biomarkers of matrix remodeling in never-treated patients with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia (FH) is a common inherited disorder of lipoprotein metabolism, whose origin involves mutations in the gene coding for the low-density lipoprotein receptor protein. Although FH is monogenic, wide variation occurs in the onset and severity of atherosclerosis in these patients.

METHODS

Since data on levels of inflammatory proteins and/or active factors in FH patients who have never received lipid-lowering treatment are lacking, serum levels of MMP-3, active MMP-9 and TIMP-1 as well as pro-inflammatory cytokines (TNF-alpha, IL-18) were determined in never-treated homozygous FH Moroccan patients (n=4) and compared to those of heterozygous FH subjects (n=7) and of healthy control subjects (n=5).

RESULTS

When compared to controls, homozygous FH patients exhibited levels of active MMP-9 and TIMP-1 (p<0.05), and of both high sensitive-CRP and IL-18 which were significantly elevated (p<0.05 and p<0.01, respectively). In heterozygous FH patients, intermediate values between FH homozygotes and healthy controls were observed for these markers, with the exception of MMP-9 activity whose levels were significantly elevated (p<0.05). Multivariate analysis revealed a positive correlation between apolipoprotein B, TIMP-1 and IL-18 levels, and between hs-CRP and IL-18 (p<0.01).

CONCLUSIONS

Although the sample size of this FH group was limited, our data suggest that nontreated homozygous FH patients, and to a lesser degree heterozygous FH patients, exhibit not only a markedly proinflammatory vascular state but also pronounced extracellular matrix remodeling, as reflected by elevated circulating levels of inflammatory cytokines and MMPs.

Recurrent perivascular inflammation induced by lipopolysaccharide (endotoxin) results in the formation of atheromatous lesions in vivo

Bacteria and viruses are suspected to induce arteriosclerosis; however, most investigators have focused on coincidences rather than causal relationships. The aim of this work was to establish a rabbit model in which the vessel reaction to local perivascular injection of defined bacterial products can be analyzed. A total of 23 rabbits were randomized to four groups. Groups A and B were fed a normal diet, groups C and D were fed a cholesterol-enriched diet. Groups A and C were treated with a single perivascular injection of bacterial lipopolysaccharide (LPS, endotoxin) placed next to auricular, carotid and femoral arteries, and sodium chloride placed next to the contralateral arteries (control). Group B and D animals were treated with repeated perivascular injections over 90 days. Vascular tissues (n=116 treated segments of 23 rabbits) were analyzed using morphometry at histology, and using immunohistochemistry to detect macrophages, lymphocytes and vascular smooth muscle cells. LPS treatment resulted in transient focal intima thickening. After single LPS application, no increase in atheromatous lesion formation was observed in comparison with controls (group C, lesion area index 0.031+/-0.012 vs 0.015+/-0.006, P=1.0). Repeated LPS application resulted in significant atheromatous lesion formation compared with saline control (group D, lesion area index 0.148+/-0.049 vs 0.008+/-0.006, P=0.003) in hypercholesterolemic rabbits. Repeated LPS inflammation in normocholesterolemic did not lead to atheromatous lesion formation (intima media ratio 0.04+/-0.01 vs 0.04+/-0.007, P=1.0). Single perivascular administration of low-dose bacterial LPS resulted in transient focal intimal thickening, while significant increase in lesion formation occurred after repeated LPS application in cholesterol-fed animals. In conclusion, this animal model will allow the assessment of the impact of defined dosages of different bacterial pathogens onto the vascular wall in the context of atherogenesis. The atheromatous lesion-promoting effect of repeated perivascular administration of LPS supports the hypothesis that bacterial pathogens may be involved in atherogenesis.

Changes in oxidative stress and microcirculation by low-density lipoprotein apheresis

Low-density lipoprotein apheresis (LDLA) leads to an improvement of microcirculation during the very early stages of treatment, and continued treatment may produce antiatherogenic effects in patients with peripheral arterial disease (PAD). Suppression of oxidative stress, improvement of endothelial functions and alteration in the action of vasoactive compounds may occur with the improvement of the rheological property of blood as a result of aggressive removal of atherogenic factors including LDL, possibly resulting in the suppression of development of atherosclerosis. As these effects of LDLA may ameliorate not only PAD but also ischemia in other organs, it is suggested that repeated LDLA prevents the progression of atherosclerotic diseases and probably improves the long-term prognosis of patients with PAD.

Low-density lipoprotein apheresis in the treatment of peripheral arterial disease

Low-density lipoprotein (LDL) apheresis is performed in patients with homozygous familial hyper-cholesterolemia who lack LDL receptors and with heterozygous familial hypercholesterolemia who are LDL receptor deficient with documented, symptomatic coronary artery disease who are resistant to diet changes and maximum drug therapy. LDL apheresis can reduce or abolish anginal symptoms and improve coronary lesions. Several reports reveal the improvement of insufficient peripheral blood flow. By extensively removing blood LDL and changing coagulation factors and various vasoactive substances, LDL apheresis improves blood rheology and thereby peripheral circulation. It seems worth trying on all patients with arteriosclerotic lesions, even if they are normocholesterolemic.

Native LDL potentiate TNF alpha and IL-8 production by human mononuclear cells

Native LDL (nLDL) increases expression of adhesion molecules on endothelial cells through induction of Ca(2+) mobilization. Ca(2+) mobilization is also involved in the induction of proinflammatory cytokines, important mediators involved in atherogenesis. The aim of the study was to evaluate the capacity of nLDL to affect spontaneous and lipopolysaccharide (LPS)-stimulated cytokine production. Preincubation of human peripheral blood mononuclear cells (PBMC) with nLDL for 24 h did not influence spontaneous production of tumor necrosis factor alpha (TNF alpha) or interleukin-8 (IL-8), but significantly potentiated LPS-induced production of these cytokines. nLDL preincubation of PBMC did not increase the expression of the LPS receptors Toll-like receptor-4, CD14, or CD11c/CD18. Potentiation of cytokine production by nLDL was mediated through induction of Ca(2+) mobilization, because: a) nLDL induced a sustained pattern of repetitive Ca(2+) transients in human PBMC; b) the Ca(2+) chelator fura 2-acetoxymethyl ester, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, an intracellular Ca(2+) chelator, inhibited the potentiating effect of nLDL on LPS-induced cytokine synthesis; c) induction of Ca(2+) mobilization by thapsigargin potentiated LPS-induced cytokine production. nLDL are able to potentiate LPS-induced production of cytokines by human PBMC, and this effect is probably mediated through induction of Ca(2+) mobilization. This may represent an important pathogenetic mechanism in atherogenesis induced by hyperlipoproteinemia.

Infiltrating CD14+ monocytes and expression of CD14 by activated parenchymal microglia/macrophages contribute to the pool of CD14+ cells in ischemic brain lesions

CD14, a key pattern recognition receptor of the innate immune system, is a surface molecule on monocytic cells involved in cellular activation. We investigated 18 autopsy cases of focal cerebral infarctions (FCI) by immunohistochemistry to examine CD14 expression following ischemia. Controls confirmed constitutive CD14 expression by few perivascular cells. In contrast to quiescent CD14- parenchymal microglial cells, following ischemia activated microglia/macrophages expressed abundant CD14. In FCI, CD14+ cells increased both in perivascular spaces and in brain parenchyma within 1-2.5 days and remained elevated until late stages. Early CD14 expression suggests an essential part of CD14 in the acute inflammatory response following stroke.

Effect of simvastatin on monocyte adhesion molecule expression in patients with hypercholesterolemia

Increased monocyte adherence to the vessel wall is one of the earliest events in atherosclerosis. The mechanism by which hypercholesterolemia causes alterations in endothelial adhesiveness for monocytes is unclear. This study sought to determine if monocyte adhesion molecule expression is affected by low-density lipoprotein (LDL)-cholesterol levels. Patients with hypercholesterolemia and stable coronary artery disease were compared with those without major cardiovascular risk (control). Patients with hypercholesterolemia were treated with simvastatin 20--40 mg/day for 8--10 weeks. Blood samples were examined with flow cytometry assays at baseline and after cholesterol-lowering therapy. Monocyte CD11b and CD14 adhesion molecule expression, measured as fluorescence intensity, were significantly (P<0.0001) higher in hypercholesterolemic patients before the study (176.9+/-9.8 and 138.0+/-4.8, respectively) when compared with that in control subjects (97.2+/-8.1 and 84.0+/-6.4, respectively). Both decreased markedly with treatment: to 118.8+/-6.9 and 103.1+/-3.9, respectively. Monocyte L-selectin expression was significantly lower in patients with hypercholesterolemia before treatment (43.0+/-3.0) when compared with control subjects (79.9+/-2.7), and it increased markedly with treatment (54.2+/-2.5). LDL levels correlated directly with both CD11b and CD14 expression and correlated inversely with L-selectin expression. These data show that hypercholesterolemia affects monocyte adhesion molecule expression which, in turn, decreases with statin-induced plasmatic cholesterol reduction. Such perturbations in monocyte function likely represent a proinflammatory response to hypercholesterolemia and may have a role in the early progression of atherogenesis.

Distinct effects of LDL apheresis by hemoperfusion (DALI) and heparin-induced extracorporeal precipitation (HELP) on leukocyte respiratory burst activity of patients with familial hypercholesterolemia

Hypercholesterolemia and oxidative stress are major risk factors in atherogenesis. In the last years, lipid apheresis has been established as an effective clinical therapy by lowering not only elevated plasma low-density lipoprotein (LDL) levels but also by reducing the incidence of cardiovascular events. The aim of the present study was to investigate peripheral leukocyte oxidant generation in patients with familial hypercholesterolemia (FH) undergoing regular LDL apheresis. The activity state of leukocytes was estimated prior to, immediately after, and 2 days after LDL apheresis carried out by two distinct techniques: hemoperfusion with the DALI system and heparin-induced extracorporeal LDL precipitation (HELP). Oxidant generating activity was measured by chemiluminescence (CL) in whole blood and isolated polymorphonuclear leukocytes (PMNL). The results of our study show increased baseline respiratory burst activities in FH patients as compared to healthy controls. Apheresis with the HELP system was followed by increases in leukocyte count, zymosan-induced whole blood CL, and plasma PMNL elastase levels. The DALI technique caused no changes in leukocyte count and elastase levels and decreased whole blood CL activity. Two days after lipid removal the observed changes returned to pre-apheresis levels. Leukocyte activity parameters before and after apheresis did not correlate with the corresponding plasma levels of triglycerides, total cholesterol, and LDL cholesterol, suggesting that different handling in the framework of both apheresis techniques rather than lipid profile changes during therapy accounted for leukocyte activity modulation.

Association of serum tumour necrosis factor-alpha with serum low-density lipoprotein-cholesterol and blood pressure in apparently healthy Japanese women

1. The pro-inflammatory cytokine tumour necrosis factor (TNF)-alpha is considered to be involved in the development of atherosclerosis by inducing local inflammatory responses in the vascular wall. Because TNF-alpha is also known to affect lipid and glucose metabolism, the association between the circulating concentration of TNF-alpha and atherogenic risk factors was examined in 82 apparently healthy Japanese women (aged 19-69 years; mean age 48.5 years). 2. The mean (+/-SD) serum TNF-alpha concentration was 2.7+/-0.9 pg/mL (range 1.4-5.9 pg/mL). The TNF-alpha concentration showed significant correlations with age (r = 0.28; P = 0.01), body mass index (r = 0.27; P = 0.01), the waist-hip ratio (r = 0.41; P = 0.0002), percentage body fat (r = 0.30; P = 0.006), systolic (r = 0.32; P = 0.004) and diastolic (r = 0.24; P = 0.03) blood pressure, total cholesterol (r = 0.27; P = 0.02) and low-density lipoprotein-cholesterol (LDL-C; r = 0.36; P = 0.001), while the correlations with high-density lipoprotein-cholesterol (r = -0.20; P = 0.08) and insulin resistance estimated by the homeostasis model assessment (HOMA(IR); r = 0.16; P = 0.15) were not statistically significant. 3. When adjusted for age and menopause, TNF-alpha was significantly associated with systolic blood pressure (r = 0.25; P = 0.02) and LDL-C (r = 0.27; P = 0.02). The association between TNF-alpha and LDL-C remained significant when adjustment was made for age, menopause and the waist-hip ratio (r = 0.24; P = 0.03). 4. Our results indicate that TNF-alpha may play a role in modulating blood pressure and LDL-C.

Novel mechanisms linking angiotensin II and early atherogenesis

We propose that Ang II exerts an as yet uncharacterized immunomodulatory effect on monocyte maturation, differentiation, or extravasation, which may depend on the myelomonocytic phenotype. Since the myelopoietic process originating at stem cells and culminating in release to the blood is at least 6 days, it is conceivable that the observation of reduced monocyte CD11b expression two weeks after completion of losartan treatment indicates a suppression of the CD11b phenotype in newly released CD14(+)/CD45(+) monocytes. Other studies employing suppression of AT(1)-receptors with deoxy-oligonucleotides have reported effects on blood pressure that surpass those predicted by the duration of the treatment.(87) These data would suggest that it is possible to interrupt a stimulatory signal by Ang II through a gene-related mechanism that in our experiments may reside in the mechanisms that regulate myelopoiesis. While our knowledge of the role of Ang II in the regulation of monocyte formation and function is incomplete, we have taken a first step in attempting to synthesize the data described above into a comprehensive hypothesis for further evaluation of the factors that initiate atherogenesis. Such effects may crucially contribute to the clinical benefit of AT(1)-receptor antagonists, independent of depressor effects, and may represent a paradigm for novel, anti-inflammatory actions by this class of drugs.

Therapeutic effects of LDL apheresis in the prevention of atherosclerosis

The efficacy and safety of the therapeutic tool which directly removes LDL particles from circulation (LDL apheresis) has already been established for cholesterol-lowering in patients with refractory hypercholesterolemia, such as homozygous familial hypercholesterolemia. Several angiographic studies have demonstrated that regular LDL apheresis therapy had favorable effects on the progression of coronary atherosclerosis. Recently, two clinical reports described excellent long-term follow-up results for patients with coronary artery disease who had been treated with LDL apheresis using dextran sulfate cellulose columns plus adjunctive cholesterol-lowering drug therapy. In addition, there is increasing evidence that LDL apheresis is effective for the prevention of extra-coronary atherosclerotic disease, and it is also reported to have the potential to improve microvascular disorders. Since the mechanisms of clinical improvement caused by LDL apheresis extend beyond simple and drastic reduction of LDL cholesterol, further investigation based on recent vascular biological evidence is needed.

Integrin mediated adhesion of mononuclear cells from patients with familial hypercholesterolemia

BACKGROUND

Low-density lipoproteins (LDL) can induce the adhesion of monocytes to endothelial cells. Monocytes of patients with familial hypercholesterolemia (FH) are exposed to high concentrations of LDL, and it has been reported that adhesiveness of these cells in hypercholesterolemic patients is enhanced. We investigated whether LFA-1 or VLA-4 mediated adhesion is altered in FH patients and whether HMG-CoA reductase inhibitors influence this adhesion.

PATIENTS AND METHODS

LFA-1 and VLA-4 mediated adhesion to ICAM-1 and VCAM-1 coated beads was investigated using freshly isolated monocytes and T-lymphocytes from patients with homozygous FH, heterozygous FH (before and after cholesterol lowering treatment), and from controls. In addition, the expression of beta1- and beta2-integrins on these cells was determined.

RESULTS

Both LFA-1 and VLA-4 mediated adhesion and integrin expression of monocytes and CD3+ cells from patients with homozygous FH and heterozygous FH was similar to that of monocytes from a control population. Treatment with HMG-CoA reductase inhibitors did not affect the adherence to ICAM-1 or VCAM-1, and did not influence the expression of integrins.

CONCLUSIONS

In contrast to studies by others, we demonstrated in the present study that the actual LFA-1 and VLA-4 mediated adhesion of T-lymphocytes and monocytes is not altered in patients with FH.