Functional impairment of HDL may contribute to the excess cardiovascular mortality experienced by patients with renal disease, but the effect of advanced renal disease on the composition and function of HDL is not well understood. Here, we used mass spectrometry and biochemical analyses to study alterations in the proteome and lipid composition of HDL isolated from patients on maintenance hemodialysis. We identified a significant increase in the amount of acute phase protein serum amyloid A1, albumin, lipoprotein-associated phospholipase A2, and apoC-III composing uremic HDL. Furthermore, uremic HDL contained reduced phospholipid and increased triglyceride and lysophospholipid. With regard to function, these changes impaired the ability of uremic HDL to promote cholesterol efflux from macrophages. In summary, the altered composition of HDL in renal disease seems to inhibit its cardioprotective properties. Assessing HDL composition and function in renal disease may help identify patients at increased risk for cardiovascular disease.

This article is available online at http://www.jlr.org more than the skin ( 1 ). Traditional cardiovascular risk factors, such as hypertension, dyslipidemia, and obesity, are more frequent in psoriatic patients ( 2-4 ). However, even after adjusting for these risk factors, psoriasis has been shown to be associated with a higher incidence of myocardial infarction, stroke, and cardiovascular mortality ( 3,5,6 ). In moderate to severe psoriasis, a signifi cantly deteriorated lipid profi le was observed compared with healthy controls, with higher values of low-density lipoprotein, triglycerides, and signifi cantly decreased HDL levels ( 7 ).Recent studies clearly demonstrated that infl ammation impairs reverse cholesterol transfer in vivo ( 8, 9 ), providing evidence that infl ammation impairs HDL function. Emerging evidence suggests that assessment of HDL plasma concentrations alone is insuffi cient and indicate that the quality, rather than the mere quantity, of HDL determines its potential benefi cial effects against atherosclerosis ( 10 ). HDL is a complex lipoprotein particle with a broad variety of functions, also exerting atheroprotective activity via effects on the endothelium and by potent antiinfl ammatory capabilities ( 11-13 ). Recent studies have identifi ed HDL-associated proteins to be involved in the regulation of lipid metabolism, complement activation, growth-factor secretion, and proteolysis (14)(15)(16)(17)(18)(19).Functional impairment of HDL may contribute to the increased cardiovascular mortality experienced by psoriatic patients, but the impact of psoriasis on the composition and function of HDL has not been assessed. As qualitative alterations of HDL seem to be linked with increased cardiovascular complications, we hypothesized that HDL from psoriatic patients displays altered protein cargo and lipid composition, thereby rendering HDL dysfunctional.Abstract Psoriasis, a chronic infl ammatory skin disease, has been linked to increased myocardial infarction and stroke. Functional impairment of HDL may contribute to the excess cardiovascular mortality of psoriatic patients. However, data available regarding the impact of psoriasis on HDL composition and function are limited. HDL from psoriasis patients and healthy controls was isolated by ultracentrifugation and shotgun proteomics, and biochemical methods were used to monitor changed HDL composition. We observed a signifi cant reduction in apoA-I levels of HDL from psoriatic patients, whereas levels of apoA-II and proteins involved in acute-phase response, immune response, and endopeptidase/protease inhibition were increased. Psoriatic HDL contained reduced phospholipid and cholesterol. With regard to function, these compositional alterations impaired the ability of psoriatic HDL to promote cholesterol effl ux from macrophages. Importantly, HDLcholesterol effl ux capability negatively correlated with psoriasis area and severity index. We observed that control HDL, as well as psoriatic HDL, inhibited dihydrorhodamine (DHR) oxidation to a similar...

Aim-Carbamylation of proteins through reactive cyanate has been demonstrated to predict an increased cardiovascular risk. Cyanate is formed in vivo by break-down of urea and at sites of inflammation by the phagocyte protein myeloperoxidase. Since myeloperoxidase (MPO) associates with high-density lipoprotein (HDL) in human atherosclerotic intima, we examined in the present study whether cyanate specifically targets HDL.Results-Mass spectrometry analysis revealed that protein carbamylation is a major posttranslational modification of HDL. The carbamyllysine content of lesion derived HDL was more Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts than 20-fold higher in comparison to 3-chlorotyrosine levels, a specific oxidation product of MPO. Notable, the carbamyllysine content of lesion-derived HDL was 5 to 8-fold higher when compared to lesion derived low-density lipoprotein (LDL) or total lesion protein and increased with lesion severity. Importantly, the carbamyllysine content of HDL, but not of LDL, correlated with levels of 3-chlorotyrosine, suggesting MPO mediated carbamylation in the vessel wall. Remarkably, one carbamyllysine residue per HDL associated apolipoprotein A-I was sufficient to induce cholesterol accumulation and lipid droplet formation in macrophages through a pathway requiring the HDL receptor scavenger receptor class B, type I. Conclusion-The present results raise the possibility that HDL carbamylation contributes to foam cell formation in atherosclerotic lesions.

Abstract-Although maternal-fetal cholesterol transfer may serve to compensate for insufficient fetal cholesterol biosynthesis under pathological conditions, it may have detrimental consequences under conditions of maternal hypercholesterolemia leading to preatherosclerotic lesion development in fetal aortas. Maternal cholesterol may enter fetal circulation by traversing syncytiotrophoblast and endothelial layers of the placenta. We hypothesized that endothelial cells (ECs) of the fetoplacental vasculature display a high and tightly regulated capacity for cholesterol release. Using ECs isolated from human term placenta (HPECs), we investigated cholesterol release capacity and examined transporters involved in cholesterol efflux pathways controlled by liver-X-receptors (LXRs). HPECs demonstrated 2.5-fold higher cholesterol release to lipid-free apolipoprotein (apo)A-I than human umbilical vein ECs (HUVECs), whereas both cell types showed similar cholesterol efflux to high-density lipoproteins (HDLs). Interestingly, treatment of HPECs with LXR activators increased cholesterol efflux to both types of acceptors, whereas no such response could be observed for HUVECs. In line with enhanced cholesterol efflux, LXR activation in HPECs increased expression of ATP-binding cassette transporters ABCA1 and ABCG1, while not altering expression of ABCG4 and scavenger receptor class B type I (SR-BI). Inhibition of ABCA1 or silencing of ABCG1 decreased cholesterol efflux to apoA-I (Ϫ70%) and HDL 3 (Ϫ57%), respectively. Immunohistochemistry localized both transporters predominantly to the apical membranes of placental ECs in situ. Thus, ECs of human term placenta exhibit unique, efficient and LXR-regulated cholesterol efflux mechanisms. We propose a sequential pathway mediated by ABCA1 and ABCG1, respectively, by which HPECs participate in forming mature HDL in the fetal blood. (Circ Res. 2009;104:600-608.)Key Words: maternal-fetal cholesterol transfer Ⅲ endothelial cells Ⅲ HDL Ⅲ liver X receptors C holesterol is indispensable during fetal development. 1 It has been long assumed that most, if not all, cholesterol required for fetal growth is synthesized de novo by the fetus itself, thus making it autonomous from maternal or placental cholesterol supply. However, several lines of evidence have cast doubt on this notion. 2,3 Fetuses that lack the ability to synthesize cholesterol, such as those with the Smith-LemliOpitz syndrome, are, nevertheless, born with low levels of tissue and plasma cholesterol, indicating that they have acquired maternal cholesterol in utero. 4 Recent exciting studies demonstrated a strong correlation between the size and number of atherosclerotic lesions in human fetal arteries with maternal cholesterol levels. 5,6 Moreover, maternal hypercholesterolemia also modified early predictors of cardiovascular disease in the offspring, thus corroborating the concept of developmental programming of adult disease in human. 7 Considering that progression of atherosclerosis in adults takes ages, these striking resu...

BackgroundHofbauer cells (HBCs) are macrophages of the feto-placental unit. Despite the general view that these cells have an anti-inflammatory M2 phenotype, recent studies have claimed that pregnancy pathologies—e.g., gestational diabetes mellitus (GDM)—cause a switch from an M2 to an M1 pro-inflammatory phenotype in HBCs. The pilot-study presented here challenges this claim, showing that HBCs maintain anti-inflammatory properties in spite of the hyperglycemic, low-grade inflammatory environment of GDM.MethodsHBCs were isolated from placentae of healthy women (N = 5) and women with GDM (N = 6) diagnosed in the second trimester. FACS was used to measure surface markers associated with either M1 or M2 phenotype on the cells. In addition, placental tissue sections were subjected to immune histochemical imaging to assess the phenotype within the tissue context. Supernatant from control and GDM HBCs was collected at defined time points and used in a multiplex ELISA-on-beads approach to assess secretion of cytokines, chemokines, and growth factors. The effect of HBC cell culture supernatant on placental endothelial activation was investigated.ResultsFACS and immune staining showed that, indeed, M2 markers, such as CD206 and CD209, are increased in HBCs isolated from GDM placentae. Also, the M1 marker CD86 was increased, but only by trend. Secretion of numerous cytokines, chemokines and growth factors was not changed; pro-inflammatory interleukin (IL)-1β and IL-6 release form GDM HBC was increased but not significant. Exposure to GDM HBC supernatant did not induce cell adhesion molecules (VCAM-1, selectins, vascular endothelial-cadherin) in placental endothelial cells compared to supernatant from control HBCs, an induction of intracellular adhesion molecule 1 was observed however.ConclusionOur study—although performed in a small set of patients—shows that placental macrophages maintain their anti-inflammatory, tissue remodeling M2 phenotype even in pregnancies affected by gestational diabetes. This consistent phenotype might be important for propagation of maternal tolerance toward the fetus and for protection of the fetus from a low-grade inflammatory environment.