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High-density lipoprotein (HDL)-bound apolipoprotein M/sphingosine 1-phosphate (ApoM/S1P) complex in cardiovascular diseases serves as a bridge between HDL and endothelial cells, maintaining a healthy endothelial barrier. To date, S1P and ApoM in patients with untreated heterozygous familial hypercholesterolemia (HeFH) have not been extensively studied. Eighty-one untreated patients with HeFH and 32 healthy control subjects were included in this study. Serum S1P, ApoM, sCD40L, sICAM-1, sVCAM-1, oxLDL, and TNFα concentrations were determined by ELISA. PON1 activities were measured spectrophotometrically. Lipoprotein subfractions were detected by Lipoprint. We diagnosed FH using the Dutch Lipid Clinic Network criteria. Significantly higher serum S1P and ApoM levels were found in HeFH patients compared to controls. S1P negatively correlated with large HDL and positively with small HDL subfractions in HeFH patients and the whole study population. S1P showed significant positive correlations with sCD40L and MMP-9 levels and PON1 arylesterase activity, while we found significant negative correlation between sVCAM-1 and S1P in HeFH patients. A backward stepwise multiple regression analysis showed that the best predictors of serum S1P were large HDL subfraction and arylesterase activity. Higher S1P and ApoM levels and their correlations with HDL subfractions and inflammatory markers in HeFH patients implied their possible role in endothelial protection.

Pigment epithelium-derived factor (PEDF) is a serin protease inhibitor and a potent inhibitor of angiogenesis. Its serum level has significant associations with metabolic parameters. However, little is known about the association between PEDF levels and lipid parameters in renal transplanted (TX) patients. Therefore, our aim was to investigate the relationship between PEDF level and lipid parameters in TX patients.Seventy TX patients (47 males, 23 females, mean age 51.7 ± 12.4 years) and 34 healthy controls were enrolled. We examined the serum creatinine, C-reactive protein, fasting glucose and lipid parameters right before, then 1 and 6 months after TX. High-density lipoprotein (HDL)-associated paraoxonase-1 (PON1) activities were measured spectrophotometrically. Lipoprotein subfractions were determined by Lipoprint. PEDF and oxidized low-density liporotein (oxLDL) levels were measured by ELISA.Before transplantation, patients had had a significantly higher PEDF level compared to control subjects (PEDF may play an important role in the increased oxidative stress and enhanced atherogenesis in renal transplant patients.

Cardiovascular (CV) morbidity, mortality and metabolic syndrome are associated with rheumatoid arthritis (RA). A recent trial has suggested increased risk of major CV events (MACE) upon the Janus kinase (JAK) inhibitor tofacitinib compared with anti-tumor necrosis factor α (TNF-α) therapy. In our study, we evaluated lipids and other metabolic markers in relation to vascular function and clinical markers in RA patients undergoing one-year tofacitinib therapy.Thirty RA patients treated with either 5 mg or 10 mg bid tofacitinib were included in a 12-month follow-up study. Various lipids, paraoxonase (PON1), myeloperoxidase (MPO), thrombospondin-1 (TSP-1) and adipokine levels, such as adiponectin, leptin, resistin, adipsin and chemerin were determined. In order to assess flow-mediated vasodilation (FMD), common carotid intima-media thickness (IMT) and arterial pulse-wave velocity (PWV) ultrasonography were performed. Assessments were carried out at baseline, and 6 and 12 months after initiating treatment.One-year tofacitinib therapy significantly increased TC, HDL, LDL, APOA, APOB, leptin, adipsin and TSP-1, while significantly decreasing Lp(a), chemerin, PON1 and MPO levels. TG, lipid indices (TC/HDL and LDL/HDL), adiponectin and resistin showed no significant changes. Numerous associations were found between lipids, adipokines, clinical markers and IMT, FMD and PWV (JAK inhibition by tofacitinib exerts balanced effects on lipids and other metabolic markers in RA. Various correlations may exist between metabolic, clinical parameters and vascular pathophysiology during tofacitinib treatment. Complex assessment of lipids, metabolic factors together with clinical parameters and vascular pathophysiology may be utilized in clinical practice to determine and monitor the CV status of patients in relation with clinical response to JAK inhibition.

Familial hypercholesterolemia (FH) is an autosomal dominant trait characterized by elevated LDL-C concentrations and is associated with an increased risk of premature atherosclerosis. Progranulin (PGRN) is a multifunctional protein that is known to have various anti-atherogenic effects. To date, the use of serum PGRN in patients with FH has not been studied.In total, 81 untreated patients with heterozygous FH (HeFH) and 32 healthy control subjects were included in this study. Serum PGRN, sICAM-1, sVCAM-1, oxLDL and TNFα concentrations were determined by ELISA. Lipoprotein subfractions were detected by Lipoprint. We diagnosed FH using the Dutch Lipid Clinic Network criteria.We could not find a significant difference between the PGRN concentrations of the HeFH patients and controls (37.66 ± 9.75 vs. 38.43 ± 7.74 ng/mL, ns.). We found significant positive correlations between triglyceride, TNFα, sVCAM-1, the ratio of small HDL subfraction and PGRN, while significant negative correlations were found between the ratio of large HDL subfraction and PGRN both in the whole study population and in FH patients. PGRN was predicted by sVCAM-1, logTNFα and the ratio of small HDL subfraction.The strong correlations between HDL subfractions, inflammatory markers and PGRN suggest that PGRN may exert its anti-atherogenic effect in HeFH through the alteration of HDL composition and the amelioration of inflammation rather than through decreasing oxidative stress.

BACKGROUND Afamin is a plasma vitamin E-binding glycoprotein partially associated with ApoA1-containing high-density lipoprotein (HDL) subfractions. In a previous study, the serum vitamin E decreased after low-density lipoprotein (LDL) apheresis, while vitamin E/cholesterol ratio increased. We aimed to study the effect of LDL apheresis on serum afamin level. METHODS The serum level of afamin and oxidized LDL were measured by enzyme-linked immunosorbent assay in six severe heterozygous FH patients before and after their first LDL apheresis treatments and in seven healthy controls. We also investigated the changes in total cholesterol, LDL-C, HDL-C, ApoB, ApoA1, HDL subfractions, and α- and γ-tocopherol levels during the treatment. HDL subfractions were detected by an electrophoretic method on polyacrylamide gel (Lipoprint). Serum α- and γ-tocopherol levels were detected by gas chromatography-mass spectrometry. RESULTS The first treatment sessions decreased serum afamin levels by an average of 9.4%. Total cholesterol, LDL-C, HDL-C and ApoA1 levels decreased by 52.6; 61.8; 10.5; and 14.1%, respectively. We found that α- and γ-tocopherol levels markedly decreased (by 34.1 and 32.9%, respectively), while α- tocopherol/cholesterol and γ-tocopherol/cholesterol ratios significantly increased (by 41.4 and 40.3%, respectively). Oxidized LDL levels significantly decreased. There was a shift toward the larger HDL subfractions. CONCLUSION LDL apheresis moderately decreases the circulating levels of afamin parallel to lowering HDL-C and ApoA1 levels. Tocopherol levels decreases markedly compared to afamin levels, however, beneficial changes in vitamin E/cholesterol ratios, oxidized LDL levels and HDL subfraction distribution were detected. These additional effects of LDL apheresis may result in further cardiovascular risk reduction in FH patients.

Abstract. Background: In hyperlipidaemic state, increased levels of myeloperoxidase (MPO) and decreased paraoxonase-1 (PON1) activity have been reported; however, their relationships with other atherosclerotic biomarkers have not been completely clarified. Patients and methods: Serum concentrations of lipid and inflammatory parameters, MPO levels, and PON1 activities were investigated in 167 untreated hyperlipidaemic patients with and without vascular complications and in 32 healthy controls. Additionally, levels of CD40 ligand (sCD40L) and asymmetric dimethyl arginine (ADMA), soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1, and oxidized LDL were determined. Results: We found elevated C-reactive protein (CRP), ADMA, sCD40L, sICAM-1 concentrations, and higher MPO levels in patients with vascular complications compared to those without. The PON1 arylesterase activity correlated negatively with sCD40L, ADMA, and sICAM-1 levels, respectively. In contrast, MPO concentrations showed positive correlations with sCD40L, ADMA, and sICAM-1 levels, respectively. Conclusions: It can therefore be stated that PON1 activity and MPO level correlate strongly with the vascular biomarkers, highlighting the importance of the HDL-associated pro- and antioxidant enzymes in the development of endothelial dysfunction and atherogenesis.

Myeloperoxidase (MPO), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) were shown to contribute to atherogenesis, while human paraoxonase-1 (PON1) protects against oxidative stress. Although several studies investigated these biomarkers, their associations have not been completely clarified yet. We aimed to investigate these parameters in overweight hyperlipidemic, lipid-lowering therapy-naive patients (n=167) with and without vascular complications.MPO, MMP-9 and TIMP-1 levels were measured by ELISA. PON1 activities were detected spectrophotometrically. PON1 phenotype was calculated by using a dual substrate method.Patients with vascular complications (VC) had significantly higher MPO and TIMP-1 levels compared to those without (patients with no vascular complications; NVC) (728 (367.25-1177.90) mg/ml vs. 315.9 (176.05-687.40) mg/ml; p0.001; and 172.7 (157.7-197.7) ng/ml vs. 152.6 (129.3-172.3) ng/ml; p0.0001; respectively). MPO levels showed a significant negative correlation with PON1 arylesterase activity (whole patient group (W): r=0.42, p0.0001; VC: r=0.44, p=0.01; NVC: r=0.39, p0.0001) and positive correlations with MMP-9 (W: r=0.37, p0.0001; VC: r=0.29, p=0.07; NVC: r=0.42, p0.0001) and TIMP-1 (W: r=0.42, p0.0001; VC: r=0.33, p0.05; NVC: r=0.41, p0.0001), respectively. PON1 arylesterase activity was found to be an independent predictor of MPO levels in the whole patient group (β=-0.350, p0.0001) or when studied separately in the subgroups with or without cardiovascular complications (VC: β=-0.57, p0.05; NVC: β=-0.33, p0.0001).Our results suggest that parallel investigation of MPO, MMP-9 and TIMP-1 levels and PON1 arylesterase activity may be a more accurate indicator of atherosclerosis, which may allow earlier treatment and therefore, improvement of treatment efficacy.

Afamin is a plasma vitamin E-binding glycoprotein partially associated with ApoA1-containing high-density lipoprotein (HDL) subfractions. In a previous study, the serum vitamin E decreased after low-density lipoprotein (LDL) apheresis, while vitamin E/cholesterol ratio increased. We aimed to study the effect of LDL apheresis on serum afamin level.The serum level of afamin and oxidized LDL were measured by enzyme-linked immunosorbent assay in six severe heterozygous FH patients before and after their first LDL apheresis treatments and in seven healthy controls. We also investigated the changes in total cholesterol, LDL-C, HDL-C, ApoB, ApoA1, HDL subfractions, and α- and γ-tocopherol levels during the treatment. HDL subfractions were detected by an electrophoretic method on polyacrylamide gel (Lipoprint). Serum α- and γ-tocopherol levels were detected by gas chromatography-mass spectrometry.The first treatment sessions decreased serum afamin levels by an average of 9.4%. Total cholesterol, LDL-C, HDL-C and ApoA1 levels decreased by 52.6; 61.8; 10.5; and 14.1%, respectively. We found that α- and γ-tocopherol levels markedly decreased (by 34.1 and 32.9%, respectively), while α- tocopherol/cholesterol and γ-tocopherol/cholesterol ratios significantly increased (by 41.4 and 40.3%, respectively). Oxidized LDL levels significantly decreased. There was a shift toward the larger HDL subfractions.LDL apheresis moderately decreases the circulating levels of afamin parallel to lowering HDL-C and ApoA1 levels. Tocopherol levels decreases markedly compared to afamin levels, however, beneficial changes in vitamin E/cholesterol ratios, oxidized LDL levels and HDL subfraction distribution were detected. These additional effects of LDL apheresis may result in further cardiovascular risk reduction in FH patients.

Previous studies showed that plasma levels of high-density lipoprotein (HDL) cholesterol are inversely related to risk of cardiovascular diseases. However, in the last few decades it became obvious that beyond its plasma level, HDL structure and function have a critical role in its anti-atherogenic efficacy. Apolipoprotein M (ApoM) is an HDL-associated plasma protein affecting HDL metabolism and exhibits various anti-atherosclerotic functions, such as protection against oxidation and regulation of cholesterol efflux. Sphingosine 1-phosphate (S1P) is a potent sphingolipid mediator that regulates numerous cellular responses including cell differentiation and migration, apoptosis and vascular inflammation. The majority of S1P is associated to ApoM containing HDL particles. Therefore, ApoM and S1P content of HDL have an impact on the atherosclerotic process. Moreover, HDL-ApoM and S1P content can be altered in several pathologic conditions such as coronary artery disease. This review covers the currently available data on the contribution of ApoM and S1P to HDL function in health and cardiovascular diseases. Orv Hetil. 2018; 159(5): 168-175.