Autoimmune rheumatic diseases : An update on the role of atherogenic electronegative ldl and potential therapeutic strategies

Altres ajuts: Vascular and Medicinal Research Fund, Texas Heart Institute (#765-64050), Houston, TX, USA; Ministry of Science and Technology (Taiwana grant MOST 107-2314-B-039-053-MY3); Ministerio de Sanidad, Spain (co-financed by Fondo Europeo de Desarrollo Regional (FEDER)).Atherosclerosis has been linked with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Autoimmune rheumatic diseases (AIRDs) are associated with accelerated atherosclerosis and ASCVD. However, the mechanisms underlying the high ASCVD burden in patients with AIRDs cannot be explained only by conventional risk factors despite disease-specific factors and chronic inflammation. Nevertheless, the normal levels of plasma low-density lipoprotein (LDL) cholesterol observed in most patients with AIRDs do not exclude the possibility of increased LDL atherogenicity. By using anion-exchange chromatography, human LDL can be divided into five increasingly electronegative subfractions, L1 to L5, or into electropositive and electronegative counterparts, LDL (+) and LDL (−). Electronegative L5 and LDL (−) have similar chemical composi-tions and can induce adverse inflammatory reactions in vascular cells. Notably, the percentage of L5 or LDL (−) in total LDL is increased in normolipidemic patients with AIRDs. Electronegative L5 and LDL (−) are not recognized by the normal LDL receptor but instead signal through the lectin-like oxidized LDL receptor 1 (LOX-1) to activate inflammasomes involving interleukin 1β (IL-1β). Here, we describe the detailed mechanisms of AIRD-related ASCVD mediated by L5 or LDL (−) and discuss the potential targeting of LOX-1 or IL-1β signaling as new therapeutic modalities for these diseases

The role of distinctive sphingolipids in the inflammatory and apoptotic effects of electronegative LDL on monocytes

Altres ajuts: Fundació La Marató de TV3: 158/U/2017Electronegative low-density lipoprotein (LDL(−)) is a minor LDL subfraction that is present in blood with inflammatory and apoptotic effects. We aimed to evaluate the role of sphingolipids ceramide (Cer), sphingosine (Sph), and sphingosine-1-phosphate (S1P) in the LDL(−)-induced effect on monocytes. Total LDL was subfractioned into native LDL and LDL(−) by anion-exchange chromatography and their sphingolipid content evaluated by mass spectrometry. LDL subfractions were incubated with monocytes in the presence or absence of enzyme inhibitors: chlorpromazine (CPZ), D-erythro-2-(N-myristoyl amino)-1-phenyl-1-propanol (MAPP), and N,N-dimethylsphingosine (DMS), which inhibit Cer, Sph, and S1P generation, respectively. After incubation, we evaluated cytokine release by enzyme-linked immunosorbent assay (ELISA) and apoptosis by flow cytometry. LDL(−) had an increased content in Cer and Sph compared to LDL(+). LDL(−)-induced cytokine release from cultured monocytes was inhibited by CPZ and MAPP, whereas DMS had no effect. LDL(−) promoted monocyte apoptosis, which was inhibited by CPZ, but increased with the addition of DMS. LDL enriched with Sph increased cytokine release in monocytes, and when enriched with Cer, reproduced both the apoptotic and inflammatory effects of LDL(−). These observations indicate that Cer content contributes to the inflammatory and apoptotic effects of LDL(−) on monocytes, whereas Sph plays a more important role in LDL(−)-induced inflammation, and S1P counteracts apoptosis

Presence of Ceramidase Activity in Electronegative LDL

Electronegative low-density lipoprotein (LDL(−)) is a minor modified fraction of human plasma LDL with several atherogenic properties. Among them is increased bioactive lipid mediator content, such as lysophosphatidylcholine (LPC), non-esterified fatty acids (NEFA), ceramide (Cer), and sphingosine (Sph), which are related to the presence of some phospholipolytic activities, including platelet-activating factor acetylhydrolase (PAF-AH), phospholipase C (PLC), and sphingomyelinase (SMase), in LDL(−). However, these enzymes' activities do not explain the increased Sph content, which typically derives from Cer degradation. In the present study, we analyzed the putative presence of ceramidase (CDase) activity, which could explain the increased Sph content. Thin layer chromatography (TLC) and lipidomic analysis showed that Cer, Sph, and NEFA spontaneously increased in LDL(−) incubated alone at 37 °C, in contrast with native LDL(+). An inhibitor of neutral CDase prevented the formation of Sph and, in turn, increased Cer content in LDL(−). In addition, LDL(−) efficiently degraded fluorescently labeled Cer (NBD-Cer) to form Sph and NEFA. These observations defend the existence of the CDase-like activity's association with LDL(−). However, neither the proteomic analysis nor the Western blot detected the presence of an enzyme with known CDase activity. Further studies are thus warranted to define the origin of the CDase-like activity detected in LDL(−)

Presence of Ceramidase Activity in Electronegative LDL

Ceramide; SphingomyelinaseCeramida; EsfingomielinasaCeramida; EsfingomielinasaElectronegative low-density lipoprotein (LDL(−)) is a minor modified fraction of human plasma LDL with several atherogenic properties. Among them is increased bioactive lipid mediator content, such as lysophosphatidylcholine (LPC), non-esterified fatty acids (NEFA), ceramide (Cer), and sphingosine (Sph), which are related to the presence of some phospholipolytic activities, including platelet-activating factor acetylhydrolase (PAF-AH), phospholipase C (PLC), and sphingomyelinase (SMase), in LDL(−). However, these enzymes’ activities do not explain the increased Sph content, which typically derives from Cer degradation. In the present study, we analyzed the putative presence of ceramidase (CDase) activity, which could explain the increased Sph content. Thin layer chromatography (TLC) and lipidomic analysis showed that Cer, Sph, and NEFA spontaneously increased in LDL(−) incubated alone at 37 °C, in contrast with native LDL(+). An inhibitor of neutral CDase prevented the formation of Sph and, in turn, increased Cer content in LDL(−). In addition, LDL(−) efficiently degraded fluorescently labeled Cer (NBD-Cer) to form Sph and NEFA. These observations defend the existence of the CDase-like activity’s association with LDL(−). However, neither the proteomic analysis nor the Western blot detected the presence of an enzyme with known CDase activity. Further studies are thus warranted to define the origin of the CDase-like activity detected in LDL(−).This research was funded by grants PI13/00364, PI16/00471, FIS PI019/00421, and PI20/00334 from the Instituto de Salud Carlos III, Spanish Ministry of Health (co-financed by the European Regional Development Fund). N.P. is the recipient of FI20/00252 from Instituto de Salud Carlos III. This research was supported by CIBER (Consorcio Centro de Investigación Biomédica en Red) (CB07/08/0016), Instituto de Salud Carlos III, and Ministerio de Ciencia e Innovación and Unión Europea—European Regional Development Fund. CIBERDEM (CB07/08/0016) and CIBERCV (CB16/11/00257) are Instituto de Salud Carlos III Projects. A.A.-S. is member of RETICS INVICTUS PLUS (RD16/0019/0010, the Instituto de Salud Carlos III project). N.P., S.B., N.R., and J.L.S.-Q. are members of the Quality Research Group 2017-SGR-1149 from Generalitat de Catalunya and the Group of Vascular Biology of the Spanish Society of Atherosclerosis

Obesity Surgery Improves Hypogonadism and Sexual Function in Men without Effects in Sperm Quality

Obesity is associated with hypogonadism, sexual dysfunction, and impaired fertility in men. However, its effects on semen parameters or sexual function remain debatable. This paper involves a longitudinal study in men submitted for obesity surgery at a university tertiary hospital. Patients were studied at baseline and at 6, 12, and 18 months after obesity surgery. At each visit, anthropometry measures were collected and hormonal and semen parameters were studied. Sexual function was evaluated with the International Index of Erectile Function (IIEF). A total of 12 patients were included. The average body mass index of patients decreased from 42.37 ± 4.44 to 29.6 ± 3.77 kg/m 2 at 18 months after surgery (p < 0.05). Hormonal parameters improved after obesity surgery. The proportion of sperm cells with normal morphology tended to decrease from baseline and became most significant at 18 months (5.83 ± 4.50 vs. 2.82 ± 2.08). No significant changes were found in the remaining semen parameters. Erectile function improved significantly at six months after surgery. The authors believe that, in general, the effects of obesity surgery on fertility may be limited or even deleterious (at least in the short and midterm follow-up)

Divergent Effects of Glycemic Control and Bariatric Surgery on Circulating Concentrations of TMAO in Newly Diagnosed T2D Patients and Morbidly Obese

High circulating concentrations of the gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) are significantly associated with the risk of obesity and type 2 diabetes (T2D). We aimed at evaluating the impact of glycemic control and bariatric surgery on circulating concentrations of TMAO and its microbiota-dependent intermediate, γ-butyrobetaine (γBB), in newly diagnosed T2D patients and morbidly obese subjects following a within-subject design. Based on HbA1c concentrations, T2D patients achieved glycemic control. However, the plasma TMAO and γBB concentrations were significantly increased, without changes in estimated glomerular filtration rate. Bariatric surgery was very effective in reducing weight in obese subjects. Nevertheless, the surgery reduced plasma γBB concentrations without affecting TMAO concentrations and the estimated glomerular filtration rate. Considering these results, an additional experiment was carried out in male C57BL/6J mice fed a Western-type diet for twelve weeks. Neither diet-induced obesity nor insulin resistance were associated with circulating TMAO and γBB concentrations in these genetically defined mice strains. Our findings do not support that glycemic control or bariatric surgery improve the circulating concentrations of TMAO in newly diagnosed T2D and morbidly obese patients

Lipids, biomarkers, and subclinical atherosclerosis in treatment-naive HIV patients starting or not starting antiretroviral therapy: Comparison with a healthy control group in a 2-year prospective study

Objective: To assess the effect of HIV infection and combined antiretroviral therapy (c-ART) on various proatherogenic biomarkers and lipids and to investigate their relationship with subclinical atherosclerosis in a cohort of treatment-naive HIV-infected patients. Methods: We performed a prospective, comparative, multicenter study of 2 groups of treatment-naive HIV-infected patients (group A, CD4>500 cells/mu L, not starting c-ART; and group B, CD4<500 cells/mu L, starting c-ART at baseline) and a healthy control group. Laboratory analyses and carotid ultrasound were performed at baseline and at months 12 and 24. The parameters measured were low-density lipoprotein (LDL) particle phenotype, lipoprotein-associated phospholipase A2 (Lp-PLA2), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), sCD14, sCD163, monocyte chemoattractant protein-1(MCP-1), and asymmetric dimethylarginine (ADMA). A linear mixed model based on patient clusters was used to assess differences in biomarkers between the study groups and over time. Results: The study population comprised 62 HIV-infected patients (group A, n = 31; group B, n = 31) and 22 controls. Age was 37 (30-43) years, and 81% were men. At baseline, the HIV-infected patients had a worse LDL particle phenotype and higher plasma concentration of sCD14, sCD163, hs-CRP, and LDL-Lp-PLA2 than the controls. At month 12, there was an increase in total cholesterol (p = 0.002), HDL-c (p = 0.003), and Apo A-I (p = 0.049) and a decrease in sCD14 (p = <0.001) and sCD163 (p<0.001), although only in group B. LDL particle size increased in group B at month 24 (p = 0.038). No changes were observed in group A or in the healthy controls. Common carotid intima-media thickness increased in HIV-infected patients at month 24 (Group A p = 0.053; group B p = 0.048). Plasma levels of sCD14, sCD163, and hs-CRP correlated with lipid values. Conclusions: In treatment-naive HIV-infected patients, initiation of c-ART was associated with an improvement in LDL particle phenotype and inflammatory/immune biomarkers, reaching values similar to those of the controls. HIV infection was associated with progression of carotid intima-media thickness

Subcutaneous Administration of Apolipoprotein J-Derived Mimetic Peptide -[113-122]apoJ Improves LDL and HDL Function and Prevents Atherosclerosis in LDLR-KO Mice

Mimetic peptides are potential therapeutic agents for atherosclerosis. -[113-122]apolipoprotein (apo) J (-[113-122]apoJ) is a 10-residue peptide that is predicted to form a class G* amphipathic helix 6 from apoJ; it shows anti-inflammatory and anti-atherogenic properties. In the present study, we analyzed the effect of -[113-122]apoJ in low-density lipoprotein receptor knockout mice(LDLR-KO) on the development of atherosclerosis and lipoprotein function. Fifteen-week-old female LDLR-KO mice fed an atherogenic Western-type diet were treated for eight weeks with -[113-122]apoJ peptide, a scrambled peptide, or vehicle. Peptides were administered subcutaneously three days per week (200 µg in 100 µL of saline). After euthanasia, blood and hearts were collected and the aortic arch was analyzed for the presence of atherosclerotic lesions. Lipoproteins were isolated and their composition and functionality were studied. The extent of atherosclerotic lesions was 43% lower with -[113-122]apoJ treatment than with the vehicle or scramble. The lipid profile was similar between groups, but the high-density lipoprotein (HDL) of -[113-122]apoJ-treated mice had a higher antioxidant capacity and increased ability to promote cholesterol efflux than the control group. In addition, low-density lipoprotein (LDL) from -[113-122]apoJ-treated mice was more resistant to induced aggregation and presented lower electronegativity than in mice treated with -[113-122]apoJ. Our results demonstrate that the -[113-122]apoJ peptide prevents the extent of atherosclerotic lesions, which could be partially explained by the improvement of lipoprotein functionality

Comparison of Plasma Lipoprotein Composition and Function in Cerebral Amyloid Angiopathy and Alzheimer’s Disease

Cerebral amyloid angiopathy (CAA) refers to beta-amyloid (Aβ) deposition in brain vessels and is clinically the main cause of lobar intracerebral hemorrhage (ICH). Aβ can also accumulate in brain parenchyma forming neuritic plaques in Alzheimer's disease (AD). Our study aimed to determine whether the peripheral lipid profile and lipoprotein composition are associated with cerebral beta-amyloidosis pathology and may reflect biological differences in AD and CAA. For this purpose, lipid and apolipoproteins levels were analyzed in plasma from 51 ICH-CAA patients (collected during the chronic phase of the disease), 60 AD patients, and 60 control subjects. Lipoproteins (VLDL, LDL, and HDL) were isolated and their composition and pro/antioxidant ability were determined. We observed that alterations in the lipid profile and lipoprotein composition were remarkable in the ICH-CAA group compared to control subjects, whereas the AD group presented no specific alterations compared with controls. ICH-CAA patients presented an atheroprotective profile, which consisted of lower total and LDL cholesterol levels. Plasma from chronic ICH-CAA patients also showed a redistribution of ApoC-III from HDL to VLDL and a higher ApoE/ApoC-III ratio in HDL. Whether these alterations reflect a protective response or have a causative effect on the pathology requires further investigation

Association of candidate genetic variants and circulating levels of ApoE/ApoJ with common neuroimaging features of cerebral amyloid angiopathy

IntroductionCerebral amyloid angiopathy (CAA) is characterized by the accumulation of amyloid-beta (A beta) in brain vessels and is a main cause of lobar intracerebral hemorrhage (ICH) in the elderly. CAA is associated with magnetic resonance imaging (MRI) markers of small vessel disease (SVD). Since A beta is also accumulated in Alzheimer's disease (AD) in the brain parenchyma, we aimed to study if several single nucleotide polymorphisms (SNPs) previously associated with AD were also associated with CAA pathology. Furthermore, we also studied the influence of APOE and CLU genetic variants in apolipoprotein E (ApoE) and clusterin/apolipoprotein J (ApoJ) circulating levels and their distribution among lipoproteins. MethodsThe study was carried out in a multicentric cohort of 126 patients with lobar ICH and clinical suspicion of CAA. ResultsWe observed several SNPs associated with CAA neuroimaging MRI markers [cortical superficial siderosis (cSS), enlarged perivascular spaces in the centrum semiovale (CSO-EPVS), lobar cerebral microbleeds (CMB), white matter hyperintensities (WMH), corticosubcortical atrophy and CAA-SVD burden score]. Concretely, ABCA7 (rs3764650), CLU (rs9331896 and rs933188), EPHA1 (rs11767557), and TREML2 (rs3747742) were significantly associated with a CAA-SVD burden score. Regarding circulating levels of apolipoproteins, protective AD SNPs of CLU [rs11136000 (T) and rs9331896 (C)] were significantly associated with higher HDL ApoJ content in the lobar ICH cohort. APOE epsilon 2 carriers presented higher plasma and LDL-associated ApoE levels whereas APOE epsilon 4 carriers presented lower plasma ApoE levels. Additionally, we observed that lower circulating ApoJ and ApoE levels were significantly associated with CAA-related MRI markers. More specifically, lower LDL-associated ApoJ and plasma and HDL-associated ApoE levels were significantly associated with CSO-EPVS, lower ApoJ content in HDL with brain atrophy and lower ApoE content in LDL with the extent of cSS. DiscussionThis study reinforces the relevance of lipid metabolism in CAA and cerebrovascular functionality. We propose that ApoJ and ApoE distribution among lipoproteins may be associated with pathological features related to CAA with higher ApoE and ApoJ levels in HDL possibly enhancing atheroprotective, antioxidative, and anti-inflammatory responses in cerebral beta-amyloidosis