Evidence that CD36 is expressed on red blood cells and constitutes a novel blood group system of clinical importance.

BACKGROUND AND OBJECTIVES: Polymorphic molecules expressed on the surface of certain blood cells are traditionally categorized as blood groups and human platelet or neutrophil antigens. CD36 is widely considered a platelet antigen (Naka) and anti-CD36 can cause foetal/neonatal alloimmune thrombocytopenia (FNAIT) in CD36-negative pregnant women. CD36 is used as a marker of differentiation in early erythroid culture. During the experimental culture of CD34+ cells from random blood donors, we observed that one individual lacked CD36. We sought to investigate this observation further and determine if CD36 fulfils the International Society of Blood Transfusion criteria for becoming a blood group. MATERIALS AND METHODS: Surface markers were monitored by flow cytometry on developing cells during the erythroid culture of CD34+ cells. Genetic and flow cytometric analyses on peripheral blood cells were performed. Proteomic datasets were analysed, and clinical case reports involving anti-CD36 and foetal anaemia were scrutinized. RESULTS: Sequencing of CD36-cDNA identified homozygosity for c.1133G>T/p.Gly378Val in the CD36-negative donor. The minor allele frequency of rs146027667:T is 0.1% globally and results in abolished CD36 expression. CD36 has been considered absent from mature red blood cells (RBCs); however, we detected CD36 expression on RBCs and reticulocytes from 20 blood donors. By mining reticulocyte and RBC datasets, we found evidence for CD36-derived peptides enriched in the membrane fractions. Finally, our literature review revealed severe cases of foetal anaemia attributed to anti-CD36. CONCLUSIONS: Based on these findings, we conclude that CD36 fulfils the criteria for becoming a new blood group system and that anti-CD36 is implicated not only in FNAIT but also foetal anaemia.

Association of cardiometabolic risk status with clinical activity and damage in systemic lupus erythematosus patients: A cross-sectional study.

Cardiometabolic status is a key factor in mortality by cardiovascular disease (CVD) in systemic lupus erythematosus (SLE). This study evaluated the association of cardiometabolic risk status with clinical activity and damage in SLE patients. A cross-sectional study was conducted in 158 SLE patients and 123 healthy subjects (HS). Anthropometry, glucose, hs-CRP, lipid profile, oxLDL, sCD36, anti-oxLDL antibodies, and cardiometabolic indexes were evaluated. SLE patients had dyslipidemia, higher sCD36, anti-oxLDL antibodies, hs-CRP, and risk (OR > 2) to present Castelli score ≥ 4.5, HDL-C < 40 mg/dL and LDL-C ≥ 100 mg/dL. Disease evolution time was correlated with glucose and BMI, damage with TG, and clinical activity with TG, TG/HDL-C ratio, and Kannel index. Active SLE patients had risk (OR > 2) to present a Castelli score ≥ 4.5, Kannel score ≥ 3, TG/HDL-C ratio ≥ 3 and HDL-C < 40 mg/dL. In conclusion, SLE patients have high cardiometabolic risk to CVD related to disease evolution time, and clinical activity.

Evaluation of the expression of red blood cell CD36, interleukin-6 and interleukin-8 in sickle cell anemia pediatric patients.

Sickle cell anemia (SCA) is a complex multisystem disease characterized by acute and chronic inflammation, with alterations in inflammatory cytokines and adhesion molecules. This case-control study was carried out to assess the levels of CD36, immature reticulocytes, interleukin (IL)-6 and IL8 in SCA patients (in crisis and the steady state) and healthy controls. It included 90 children who were 2-18 years old; 60 with SCA and 30 healthy controls. Complete blood count, total reticulocyte count, reticulocyte subpopulations, immature reticulocyte fraction (IRF), percentage of CD36-positive red blood cells (RBCs), IL-6 and IL-8 levels were evaluated. The total white blood cell (WBC) and neutrophil counts, CD36-positive RBCs percentage, IRF, IL-6 and IL-8 levels were significantly higher in crises than in the steady state (P < 0.05). We also found that patients with SCA had significantly higher reticulocyte, WBC and neutrophil counts, fetal hemoglobin, CD36-positive RBCs percentage, IRF, and IL-6 and IL-8 levels than healthy children (P < 0.05). A significant positive linear correlation was reported between IL-6 and neutrophils during crises (Spearman correlation coefficient = 0.397, P = 0.03). These findings suggest that the levels of adhesion molecules and inflammatory markers and IRF, as evidenced by CD36-positive RBCs, IL-6 and IL-8, are elevated in SCA patients, both during steady state and crises, although these elevations are more marked during crises. Further knowledge about these cytokines and adhesion molecules will help in understanding the pathogenesis and improve therapy of SCA.

Soluble Receptors Affecting Stroke Outcomes: Potential Biomarkers and Therapeutic Tools.

Soluble receptors are widely understood to be freestanding moieties formed via cleavage from their membrane-bound counterparts. They have unique structures, are found among various receptor families, and have intriguing mechanisms of generation and release. Soluble receptors' ability to exhibit pleiotropic action by receptor modulation or by exhibiting a dual role in cytoprotection and neuroinflammation is concentration dependent and has continually mystified researchers. Here, we have compiled findings from preclinical and clinical studies to provide insights into the role of soluble/decoy receptors, focusing on the soluble cluster of differentiation 36, the soluble cluster of differentiation 163, and soluble lipoprotein-related protein 1 (sCD36, sCD163, and sLRP1, respectively) and the functions they could likely serve in the management of stroke, as they would notably regulate the bioavailability of the hemoglobin and heme after red blood cell lysis. The key roles that these soluble receptors play in inflammation, oxidative stress, and the related pharmacotherapeutic potential in improving stroke outcomes are described. The precise pleiotropic physiological functions of soluble receptors remain unclear, and further scientific investigation/validation is required to establish their respective role in diagnosis and therapy.

Frequency of CD36 deficiency in Thais analyzed by quantification of CD36 on cell surfaces and in plasma.

BACKGROUND: Anti-CD36s, developing after transfusion or during pregnancy, play an important role in immune-mediated bleeding disorders among Asian populations. Currently, little is known about the clinical relevance of anti-CD36. Here, we aimed to determine the frequency of CD36 deficiency in Thais by analyzing CD36 expression on cell surfaces and in plasma. STUDY DESIGN AND METHODS: The expression and deficiency of CD36 on platelets and monocytes were determined by flow cytometry. Mutations in the CD36 gene were analyzed by nucleotide sequencing. Soluble CD36 (sCD36) in plasma was quantified with enzyme-linked immunosorbent assay. RESULTS: Fifteen of 700 blood donors (2.14%) were identified as CD36 deficient. The frequencies of Type I and II CD36 deficiency were 0.43% and 1.71%, respectively. Type I individuals exhibited c.1163A > T, c.429 + 4insG, and c.1156C > T. Type II individuals exhibited c.879 T > C, c.329-330delAC, c.818 + 108delAACT, c.1125 + 13C > A, and c.1163A > T. CD36 on donor platelets (n = 685) showed a wide distribution of expression levels (mean fluorescence intensity, 16.71 ± 8.68). In the normal phenotype (n = 14), sCD36 concentration was 58.84 ± 11.68 ng/mL, which was significantly correlated with platelet CD36 expression (r2 = 0.8551). In Type II-deficient individuals (n = 6), a similar sCD36 concentration was detected (53.67 ± 8.17 ng/mL). However, sCD36 could not be detected in Type I individuals (n = 3). CONCLUSION: CD36 Type I deficiency was found, indicating the potential for immune-mediated platelet disorders in Thais. However, the underlying mutations differed from those reported in Japan and China. Interestingly, sCD36 could not be detected in plasma of Type I-deficient individuals. This finding may lead to the use of plasma to identify individuals at risk and to allow screening of large cohorts.

Tanshinone IIA prevents platelet activation and down-regulates CD36 and MKK4/JNK2 signaling pathway.

BACKGROUND: Tanshinone IIA (TS IIA), a multi-pharmaceutical compound from traditional Chinese herb, is effective for treatment of atherothrombosis. However, the underlying mechanisms of TS IIA-mediated anti-platelet activation effect are still poorly understood. As shown in our previous study, platelet-derived microvesicles (PMVs) generated in response to oxidant insult could activate CD36/mitogen-activated protein kinase kinase 4/Jun N-terminal kinase 2 (CD36/MKK4/JNK2) signals and lead to platelet activation. The present study aims to investigate the effect of TS IIA on platelet activation and the possible mechanisms. METHODS: The production of PMVs induced by Interleukin 6 (IL-6) was detected by flow cytometry. We performed activating studies of platelets with PMVs derived from IL-6-treated platelets (IL-6-PMVs) in vitro. Sometimes, platelet suspensions were incubated with serial concentrations of TS IIA for 15 min before being stimulated with IL-6-PMVs. Expression of platelet integrin αIIbß3 and CD36 was detected by flow cytometry. Phosphorylation of MKK4 and JNK were detected by immunoblotting. RESULTS: Here we demonstrated firstly that TS IIA could prevent platelet activation induced by PMVs and down-regulates CD36 and MKK4/JNK2 signaling pathway. CD36 may be the target of atherosclerosis (AS)-related thrombosis. CONCLUSIONS: This study showed the possible mechanisms of TS IIA-mediated anti-platelet activation and may provide a new strategy for the treatment of AS-related thrombosis by targeting platelet CD36.

Hydrops fetalis associated with anti-CD36 antibodies in fetal and neonatal alloimmune thrombocytopenia: Possible underlying mechanism.

OBJECTIVES: In the present study, we asked whether anti-CD36 antibodies impair the maturation of erythropoietic stem cells to mature red blood cells (RBCs), leading to anaemia and hydrops fetalis (HF). BACKGROUND: Recent studies have shown the importance of anti-CD36 antibodies in the development of Fetal/Neonatal Alloimmune Thrombocytopenia (FNAIT). In comparison to other types of antibody-mediated FNAIT, anti-CD36 antibodies are frequently associated with anaemia and HF. As mature RBCs do not express CD36, the reason for this phenomenon is currently not fully understood. MATERIAL AND METHODS: A case of FNAIT with signs of HF was characterised in this study. Maternal anti-CD36 antibodies were isolated by an absorption/elution approach. We cultured haematopoietic stem cells (HSCs) with purified anti-CD36 antibodies, and the formation of burst-forming unit-erythroid and colony-forming unit-erythroid (CFU-E/BFU-E) cells was analysed. Apoptosis of HSCs was also investigated. RESULTS: Analysis of the mother showed type-1 CD36 deficiency. Anti-CD36 antibodies were found in maternal serum, as well as on fetal platelets, by ELISA, and the specificity of these antibodies was further substantiated by flow cytometry. In comparison to control IgG, incubation of HSCs with purified anti-CD36 antibodies led to a significant reduction in CFU-E/BFU-E cell formation, and this result was associated with an increased number of apoptotic CD34+ erythroid/myeloid precursor cells. Administration of intra-uterine transfusion with washed RBCs was effective in improving fetal anaemia. CONCLUSIONS: Anti-CD36 antibodies may cause anaemia and trigger HF through apoptosis of CD34+ erythroid/myeloid precursor cells. However, the contribution of other cells must also be taken into account.

Pre-diagnostic plasma concentrations of Fibrinogen, sGPIIb/IIIa, sP-selectin, sThrombomodulin, Thrombopoietin in relation to cancer risk: Findings from a large prospective study.

While enhanced platelet activation may drive cancer progression and metastases, less is known about its role in early cancer development. Thus, we evaluated whether pre-diagnostic biomarkers of platelet activation and coagulation are related to the risks of common cancers in the prospective EPIC-Heidelberg Study using a case-cohort design. Levels of fibrinogen, soluble glycoprotein (sGP) IIb/IIIa, soluble P-selectin (sP-selectin), soluble thrombomodulin (sTM), and thrombopoietin (TPO) were measured in baseline plasma samples of a random subcohort (n = 2,480) and incident cases of breast (n = 605), prostate (n = 543), and colorectal cancer (n = 249). Multivariable Cox regression models revealed no statistically significant associations between biomarker concentrations and any of the cancer endpoints. Subgroup analyses showed a significant inverse relationship between TPO and colorectal cancer among men, with a hazard ratio (HR, highest vs. lowest quartile) of 0.60 (95% confidence interval: 0.37,0.95), whereas no significant association was observed among women. With regard to fibrinogen levels and breast cancer risk, there was a significant positive association among nulliparous women (HR: 2.53 [95% CI: 1.21, 5.30]), but not among parous women. Overall, our data suggest that enhanced platelet activation and a pro-coagulative state may not be related to increased risks of common cancers, although studies on other potential biomarkers of platelet activation and further cancer types are needed. Findings from our subgroup analyses require further investigation, as potential underlying mechanisms are not known.

Prolactin improves hepatic steatosis via CD36 pathway.

BACKGROUND & AIMS: Prolactin (PRL) is a multifunctional polypeptide with effects on metabolism, however, little is known about its effect on hepatic steatosis and lipid metabolism. Herein, we aimed to assess the role of PRL in the development of non-alcoholic fatty liver disease (NAFLD). METHODS: The serum PRL levels of 456 patients with NAFLD, 403 controls without NAFLD diagnosed by ultrasound, and 85 individuals with liver histology obtained during metabolic surgery (44 female and 30 male patients with NAFLD and 11 age-matched non-NAFLD female individuals) were evaluated. The expression of the gene encoding the prolactin receptor (PRLR) and signalling molecules involved in hepatic lipid metabolism were evaluated in human liver and HepG2 cells. The effects of overexpression of PRLR or fatty acid translocase (FAT)/CD36 or knockdown of PRLR on hepatic lipid metabolism were tested in free fatty acid (FFA)-treated HepG2 cells. RESULTS: Circulating PRL levels were lower in individuals with ultrasound-diagnosed NAFLD (men: 7.9 [range, 5.9-10.3] µg/L; women: 8.7 [range, 6.1-12.4] µg/L) than those with non-NAFLD (men: 9.1 [range, 6.8-13.0] µg/L, p = 0.002; women: 11.6 [range, 8.2-16.1] µg/L, p <0.001). PRL levels in patients with biopsy-proven severe hepatic steatosis were lower compared with those with mild-to-moderate hepatic steatosis in both men (8.3 [range, 5.4-9.5] µg/L vs. 9.7 [range, 7.1-12.3] µg/L, p = 0.031) and women (8.5 [range, 4.2-10.6] µg/L vs. 9.8 [range, 8.2-15.7] µg/L, p = 0.027). Furthermore, hepatic PRLR gene expression was significantly reduced in patients with NAFLD and negatively correlated with CD36 gene expression. In FFA-induced HepG2 cells, PRL treatment or PRLR overexpression significantly reduced the expression of CD36 and lipid content, effects that were abrogated after silencing of PRLR. Furthermore, overexpression of CD36 significantly reduced the PRL-mediated improvement in lipid content. CONCLUSIONS: Our results reveal a novel association between the central nervous system and the liver, whereby PRL/PRLR improved hepatic lipid accumulation via the CD36 pathway. LAY SUMMARY: Our clinical study suggests a negative association between prolactin (PRL)/prolactin receptor (PRLR) and the presence of non-alcoholic fatty liver disease (NAFLD). Using cell experiments, we found that PRL ameliorates hepatic steatosis via the hepatic PRLR and fatty acid translocase (FAT)/CD36, a key transporter of free fatty acid uptake in liver. Our findings suggest a novel approach to improving NAFLD using PRL and PRLR. Clinical trial number: NCT03296605.

Human Blood Monocyte Subsets: A New Gating Strategy Defined Using Cell Surface Markers Identified by Mass Cytometry.

OBJECTIVE: Human monocyte subsets are defined as classical (CD14++CD16-), intermediate (CD14++CD16+), and nonclassical (CD14+CD16+). Alterations in monocyte subset frequencies are associated with clinical outcomes, including cardiovascular disease, in which circulating intermediate monocytes independently predict cardiovascular events. However, delineating mechanisms of monocyte function is hampered by inconsistent results among studies. APPROACH AND RESULTS: We use cytometry by time-of-flight mass cytometry to profile human monocytes using a panel of 36 cell surface markers. Using the dimensionality reduction approach visual interactive stochastic neighbor embedding (viSNE), we define monocytes by incorporating all cell surface markers simultaneously. Using viSNE, we find that although classical monocytes are defined with high purity using CD14 and CD16, intermediate and nonclassical monocytes defined using CD14 and CD16 alone are frequently contaminated, with average intermediate and nonclassical monocyte purity of ≈86.0% and 87.2%, respectively. To improve the monocyte purity, we devised a new gating scheme that takes advantage of the shared coexpression of cell surface markers on each subset. In addition to CD14 and CD16, CCR2, CD36, HLA-DR, and CD11c are the most informative markers that discriminate among the 3 monocyte populations. Using these additional markers as filters, our revised gating scheme increases the purity of both intermediate and nonclassical monocyte subsets to 98.8% and 99.1%, respectively. We demonstrate the use of this new gating scheme using conventional flow cytometry of peripheral blood mononuclear cells from subjects with cardiovascular disease. CONCLUSIONS: Using cytometry by time-of-flight mass cytometry, we have identified a small panel of surface markers that can significantly improve monocyte subset identification and purity in flow cytometry. Such a revised gating scheme will be useful for clinical studies of monocyte function in human cardiovascular disease.

Fatty acid transport receptor soluble CD36 and dietary fatty acid pattern in type 2 diabetic patients: a comparative study.

Recently, it has been remarked that dietary fatty acids and fatty acid receptors might be involved in the aetiology of diabetes. Therefore, this study was conducted to determine the relationship between dietary fatty acid pattern, fatty food preferences and soluble CD36 (sCD36) and insulin resistance in type 2 diabetes mellitus (DM). The study was carried out with thirty-eight newly diagnosed type 2 DM patients and thirty-seven healthy volunteers, aged 30-65 years. In the study, socio-demographic characteristics, dietary fat type and fatty acid pattern of individuals were recorded. After anthropometric measurements were taken, blood CD36, glucose, TAG and insulin levels were analysed. The results showed that although the type of fatty acid intake did not differ between the groups (P>0·05), the consumption of olive oil in the type 2 DM group was lower than the control group (P0·05). Crucially, elevated sCD36 levels increased the type 2 DM risk (OR 1·21, P<0·05). In conclusion, sCD36 level may be a possible biomarker, independent from the dietary fatty acid pattern, for type 2 DM owing to its higher levels in these patients. Therefore, the new insights make CD36 attractive as a therapeutic target for diabetes.

Assessment of potential biomarkers of atherosclerosis in Indian patients with type 2 diabetes mellitus.

BACKGROUND & OBJECTIVES: : Various biological markers of subclinical atherosclerosis have been proposed to predict cardiovascular events in patients with diabetes mellitus (DM). However, there are only a few clinical studies assessing the role of invasive biomarkers [CD-36, peroxisome proliferator-activated receptor gamma (PPAR-γ) and YKL-40] in Indian patients with type 2 DM (T2DM). Hence, the present study was conducted to assess protein levels and gene expression of CD-36, PPAR-γ and YKL-40 in patients with T2DM and compare that with hypertensive and healthy controls. METHODS: : All the participants were subjected to medical history, anthropometric measurements and biochemical and biomarker (ELISA and real-time polymerase chain reaction) estimations. The study groups consisted of patients with T2DM (>5 yr) with hypertension (n=55), patients with T2DM (<2 yr) without hypertension (n=28), hypertensive controls (n=31) and healthy controls (n=30). RESULTS: : Gene expressions of YKL-40 and CD36 were significantly higher in patients with T2DM (>5 yr) with hypertension compared to healthy controls (P=0.006). In addition, a significant increase in serum levels of sCD36, PPAR-γ and YKL-40 was observed in patients with T2DM (>5 yr) with hypertension compared to healthy controls (P< 0.05). Serum levels as well as gene expression of CD36 showed significant correlation with serum levels as well as gene expression of PPAR-γ (ρ=0.45 and ρ=0.51; P< 0.001), respectively. INTERPRETATION & CONCLUSIONS: : CD36 and YKL-40 may be potential inflammatory biomarkers for early onset of atherosclerosis in patients with T2DM.

[Association of Serum Soluble CD36 with Clinical Variables in Diabetic Patients with Chronic Kidney Diseas].

OBJECTIVE: To investigate the levels of serum soluble CD36 (sCD36) in patients of diabetes mellitus (DM) with chronic kidney disease (CKD),and to analyze its correlation with clinical indicators. METHODS: A total of 161 patients with CKD were enrolled in this study. The patients were divided into two groups according to whether they had DM or not: DM+CKD group and non-DM CKD group. The levels of carotid intima-media thickness (IMT) and the combination of atherosclerotic plaques were measured by color Doppler ultrasonography. Serum fasting serum samples were collected and serum sCD36 level was measured by ELISA. the status of serum sCD36 was analyzed with the progress of renal disease,and the correlation of sCD36 level with clinical indicators were analyzed. RESULTS: Among the 161 patients,87 (54%) were DM+CKD and 74 (46%) were non-DM CKD. There was no significant difference in the levels of urea nitrogen (BUN),serum creatinine (sCr),estimated glomerular filtration rate (eGFR),cystatin C (Cys-C),triglyceride (TG),cholesterol (Chol),low density lipoprotein-chol (LDL-C),urinary albumin/creatinine and IMT in the two groups (P>0.05). Compared with non-DM CKD group,the serum sCD36 level (U/L) in DM+CKD group was lower (4.58±1.06 vs. 4.97±1.28,P<0.05). In DM+CKD group,serum sCD36 was negatively correlated with BUN,sCr and Cys-C (r=⁻0.355,⁻0.336,⁻0.323; P<0.01),and positively correlated with eGFR (r= 0.399; P<0.01),but not with TG,Chol,LDL-C or IMT (P>0.05). In non-DM CKD group,there was a positive correlation between sCD36 and TG,Chol and LDL-C (r= 0.251, 0.298, 0.292; P<0.05),and negatively correlated with Cys-C (r=⁻0.287; P<0.05),but not with eGFR,BUN,sCr or IMT (P>0.05). With the progress of CKD,serum sCD36 levels gradually decreased (P>0.05). CONCLUSION: Serum sCD36 level is associated with renal function in the patients with DM complicated with CKD,but not with lipid indicators.

Circulating sCD36 levels in patients with non-alcoholic fatty liver disease and controls.

BACKGROUND AND OBJECTIVE: CD36 is implicated in fatty-acid uptake in multiple tissues, including hepatocytes and adipocytes. Circulating CD36 (sCD36) is increased in non-alcoholic fatty liver disease (NAFLD). We explored this association further by investigating correlations between sCD36 levels, intrahepatic lipid content and markers of obesity in NAFLD patients and controls. METHODS: In total, 111 NAFLD patients and 33 normal/overweight controls were included. Intrahepatic lipid content was measured by magnetic resonance spectroscopy; and subgroups of participants had a dual-energy X-ray absorptiometry (n=99), magnetic resonance imaging (n=94, subcutaneous and visceral adipose tissue) and liver biopsy (n=28 NAFLD patients) performed. Plasma sCD36 was assessed by enzyme-linked immunosorbent assay. RESULTS: NAFLD patients had elevated sCD36 levels compared with controls (0.68 (0.12-2.27) versus 0.43 (0.10-1.18), P<0.01). sCD36 correlated with intrahepatic lipid (rs=0.30), alanine transaminase (ALT) (r=0.31), homeostasis model assessment index-insulin resistance (r=0.24), high-density lipoprotein (r=-0.32) and triglyceride (r=0.44, all P<0.01). Intrahepatic lipid and plasma triglyceride were independent predictors of sCD36 levels in a multiple regression analysis. Further, sCD36 and body mass index were weakly correlated (r=0.17, P=0.04); yet, we found no correlations between sCD36 and other measures of fat distribution except an inverse relation to visceral adipose tissue (rs=-0.21, P<0.05). We observed a trend for correlation between sCD36 and hepatic CD36 mRNA expression (r=0.37, P=0.07). CONCLUSIONS: sCD36 levels increased with the level of intrahepatic lipid, insulin resistance and dyslipidemia. The weak association with markers of obesity and the association with hepatic CD36 mRNA expression suggest that excess sCD36 in NAFLD patients is derived from the hepatocytes, which may support that CD36 is involved in NAFLD development. An unhealthy and unbalanced CD36 expression in adipose and hepatic tissue may shift the fatty-acid load to the liver.

Pretreatment levels of the fatty acid handling proteins H-FABP and CD36 predict response to olanzapine in recent-onset schizophrenia patients.

Traditional schizophrenia pharmacotherapy remains a subjective trial and error process involving administration, titration and switching of drugs multiple times until an adequate response is achieved. Despite this time-consuming and costly process, not all patients show an adequate response to treatment. As a consequence, relapse is a common occurrence and early intervention is hampered. Here, we have attempted to identify candidate blood biomarkers associated with drug response in 121 initially antipsychotic-free recent-onset schizophrenia patients treated with widely-used antipsychotics, namely olanzapine (n=40), quetiapine (n=23), risperidone (n=30) and a mixture of these drugs (n=28). Patients were recruited and investigated as two separate cohorts to allow biomarker validation. Data analysis showed the most significant relationship between pre-treatment levels of heart-type fatty acid binding protein (H-FABP) and response to olanzapine (p=0.008, F=8.6, ß=70.4 in the discovery cohort and p=0.003, F=15.2, ß=24.4 in the validation cohort, adjusted for relevant confounding variables). In a functional follow-up analysis of this finding, we tested an independent cohort of 10 patients treated with olanzapine and found that baseline levels of plasma H-FABP and expression of the binding partner for H-FABP, fatty acid translocase (CD36), on monocytes predicted the reduction of psychotic symptoms (p=0.040, F=6.0, ß=116.3 and p=0.012, F=11.9, ß=-0.0054, respectively). We also identified a set of serum molecules changed after treatment with antipsychotic medication, in particular olanzapine. These molecules are predominantly involved in cellular development and metabolism. Taken together, our findings suggest an association between biomarkers involved in fatty acid metabolism and response to olanzapine, while other proteins may serve as surrogate markers associated with drug efficacy and side effects.

Etiopathological mechanisms and clinical characteristics of hyperhemolysis syndrome in Spanish patients with thalassemia.

Hyperhemolysis syndrome (HHS) is characterized by severe intravascular hemolysis with a decrease in the reticulocyte count, which is triggered and aggravated by transfusion and cannot be explained by standard immunohematological studies. A nationwide study was conducted in order to retrospectively identify thalassemia patients with HHS in Spain in order to assess pre-disposing mechanisms for this syndrome. For this, the expression of adhesion (CD49, CD36) and complement-related molecules (C3a, CD59) and the levels of reticulocyte apoptosis and macrophage activation were measured in 4 thalassemia patients with HHS, 14 patients without HHS, and 10 healthy subjects. Five of the six thalassemia patients had δß-thalassemia. The patients were not alloimmunized prior to the syndrome, which was developed after the first transfusion in all but one case. Patients with δß-thalassemia did not respond to corticoids or immunoglobulins; only splenectomy was successful. The expression of CD49 (α4ß1 integrin) was far higher in patients who had experienced HHS (85.07 ± 18.46 vs. 46.28 ± 24.31; p < 0.01), and the difference remained significant after correcting by the number of molecules analyzed (Bonferroni p < 0.05). In our population, δß-thalassemia was the most common hemoglobinopathy in patients with HHS. Furthermore, the risk to develop this syndrome may be associated with an increased expression of α4ß1 integrin.

CD36-dependent 7-ketocholesterol accumulation in macrophages mediates progression of atherosclerosis in response to chronic air pollution exposure.

RATIONALE: Air pollution exposure has been shown to potentiate plaque progression in humans and animals. Our previous studies have suggested a role for oxidized lipids in mediating adverse vascular effect of air pollution. However, the types of oxidized lipids formed in response to air pollutants and how this occurs and their relevance to atherosclerosis are not fully understood. OBJECTIVE: To investigate the mechanisms by which particulate matter <2.5 µm (PM2.5) induces progression of atherosclerosis. METHODS AND RESULTS: Atherosclerosis-prone ApoE(-/-) or LDLR(-/-) mice were exposed to filtered air or concentrated ambient PM2.5 using a versatile aerosol concentrator enrichment system for 6 months. PM2.5 increased 7-ketocholesterol (7-KCh), an oxidatively modified form of cholesterol, in plasma intermediate density lipoprotein/low-density lipoprotein fraction and in aortic plaque concomitant with progression of atherosclerosis and increased CD36 expression in plaque macrophages from PM2.5-exposed mice. Macrophages isolated from PM2.5-exposed mice displayed increased uptake of oxidized lipids without alterations in their efflux capacity. Consistent with these finding, CD36-positive macrophages displayed a heightened capacity for oxidized lipid uptake. Deficiency of CD36 on hematopoietic cells diminished the effect of air pollution on 7-KCh accumulation, foam cell formation, and atherosclerosis. CONCLUSIONS: Our results suggest a potential role for CD36-mediated abnormal accumulations of oxidized lipids, such as 7-KCh, in air pollution-induced atherosclerosis progression.

Circulating CD36+ microparticles are not altered by docosahexaenoic or eicosapentaenoic acid supplementation.

BACKGROUND AND AIMS: Circulating microparticles (MP) are the source of a plasma derived form of the scavenger receptor CD36, termed soluble (s)CD36, the levels of which correlate with markers of atherosclerosis and risk of cardiovascular disease. Long chain n-3 polyunsaturated fatty acids have cardioprotective effects that we have previously reported to be gender specific. The aim of this study was to determine if dietary docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA) supplementation affect circulating CD36 + MP levels, and if this occurs differentially in healthy men and women. METHODS AND RESULTS: Participants (43M, 51F) aged 39.6 ± 1.7 years received 4 weeks of daily supplementation with DHA rich (200 mg EPA; 1000 mg DHA), EPA rich (1000 mg EPA; 200 mg DHA), or placebo (sunola) oil in a double-blinded, randomised, placebo controlled trial. Plasma CD36 + MP were enumerated by flow cytometry and differences between genders and treatments were evaluated by Student's or paired t-test and one way ANOVA. Males and females had similar levels of CD36 + MP at baseline (mean = 1018 ± 325 vs 980 ± 318; p = 0.577) and these were not significantly changed after DHA (M, p = 0.571; F, p = 0.444) or EPA (M, p = 0.361; F, p = 0.901) supplementation. Likewise, the overall percent change in these levels were not different between supplemented cohorts compared to placebo when all participants were combined (% change in CD36 + MP: DHA = 5.7 ± 37.5, EPA = -3.4 ± 35.4, placebo = -11.5 ± 32.9; p = 0.158) or stratified by gender (M, DHA = -2.6 ± 30.6, EPA = -15.1 ± 20.1, placebo = -21.4 ± 28.7, p = 0.187; F, DHA = 11.7 ± 41.5, EPA = 6.8 ± 42.9, placebo = -2.8 ± 34.7, p = 0.552). CONCLUSION: The cardioprotective effects of DHA and EPA do not act through a CD36 + MP mechanism.

Platelet activation after endovascular repair of abdominal aortic aneurysm.

AIM: To investigate the effect of endovascular aneurysm repair (EVAR) on platelet (PLT) function and reveal possible associated factors. METHODS: Fifty consecutive patients were included. PLT count and activation (CD62P-CD36), white blood cell (WBC) count, and high sensitivity C-reactive protein (hs-CRP) were measured preoperatively, at the first and third postoperative day. RESULTS: EVAR elicited a significant reduction in PLT count from baseline to first day after EVAR (p < 0.001), while no significant difference was noted between the first and third day. Furthermore, CD62P expression was markedly elevated at the first day after EVAR (median % positive PLTs from 13.7 at baseline to 22.1, p = 0.05), but returned to baseline levels by the third day. Maximum abdominal aortic aneurysm diameter was the only factor that significantly affected the CD62P values (p = 0.005). Postoperative CD36 values were significantly correlated with total aneurysm volume (p = 0.05) and were higher in endografts made from polyester (p = 0.01). There were no correlation between PLT activation and hs-CRP, WBC, maximum temperature, and 30-day morbidity. CONCLUSION: EVAR has elucidated a significant reduction in PLT count and increase in PLT activation at the immediate postoperative period. The type of the endograft material and the aneurysm maximum diameter and volume appear to play an important role in PLT activation.

Association of CD36 expression and polymorphism with serum biochemical indices in Cherry Valley duck.

Cluster of differentiation 36 (CD36) plays a crucial role in lipid sensing, innate immunity, atherogenesis, and glycolipid metabolism. This aims of this study were to delineate the CD36 mRNA expression profile in 16 duck tissues using relative quantitative real-time PCR and to screen single nucleotide polymorphisms (SNPs) in the duck CD36 gene by PCR-single strand conformation polymorphism and DNA direct sequencing. In addition, this study investigated CD36 gene expression, genetic variation, and their effect on serum biochemical indices in duck. The results showed that CD36 mRNA was expressed in all tissues, and was highly specific to the pituitary and large intestine, and to subcutaneous and abdominal fat. Furthermore, three genotypes of the SNP g.476593 T > C in exon 9 of the duck CD36 gene were identified: MM, MN, and NN. The dominant genotype and allele were MM and M, with frequencies of 0.453 and 0.643, respectively. The genotype distributions deviated from Hardy-Weinberg equilibrium (P < 0.05) and achieved moderate levels of polymorphism in ducks. Correlation results showed that CD36 mRNA was significantly negatively correlated with triglycerides (P < 0.05), and significantly positively correlated with total protein, globulin, low-density lipoprotein cholesterol, and total cholesterol (P < 0.01). All serum biochemical indices measured, with the exception of triglycerides, in birds with the NN genotype were significantly higher than those in birds with the MM genotype. These findings demonstrated that CD36 might be an important genetic marker for the selection of lipid metabolism and meat quality traits in ducks.