Key Points• Highly electronegative LDL (L5), which is elevated in patients with STEMI, induces platelet activation and aggregation through LOX-1.• L5 may have a role in promoting thrombogenesis that leads to STEMI.Platelet activation and aggregation underlie acute thrombosis that leads to ST-elevation myocardial infarction (STEMI). L5-highly electronegative low-density lipoprotein (LDL)-is significantly elevated in patients with STEMI. Thus, we examined the role of L5 in thrombogenesis. Plasma LDL from patients with STEMI (n 5 30) was chromatographically resolved into 5 subfractions (L1-L5) with increasing electronegativity. In vitro, L5 enhanced adenosine diphosphate-stimulated platelet aggregation twofold more than did L1 and induced platelet-endothelial cell (EC) adhesion. L5 also increased P-selectin expression and glycoprotein (GP)IIb/IIIa activation and decreased cyclic adenosine monophosphate levels (n 5 6, P < .01) in platelets. In vivo, injection of L5 (5 mg/kg) into C57BL/6 mice twice weekly for 6 weeks shortened tail bleeding time by 43% (n 5 3; P < .01 vs L1-injected mice) and increased P-selectin expression and GPIIb/IIIa activation in platelets. Pharmacologic blockade experiments revealed that L5 signals through plateletactivating factor receptor and lectin-like oxidized LDL receptor-1 to attenuate Akt activation and trigger granule release and GPIIb/IIIa activation via protein kinase C-a. L5 but not L1 induced tissue factor and P-selectin expression in human aortic ECs (P < .01), thereby triggering platelet activation and aggregation with activated ECs. These findings indicate that elevated plasma levels of L5 may promote thrombosis that leads to STEMI. (Blood. 2013;122(22):3632-3641)

Electronegative L5 low-density lipoprotein (LDL) level may be a useful biomarker for predicting cardiovascular disease. We determined the range of plasma L5 levels in healthy adults (n = 35) and examined the power of L5 levels to differentiate patients with coronary artery disease (CAD; n = 40) or patients with hyperlipidemia (HLP) without evidence of CAD (n = 35) from healthy adults. The percent L5 in total LDL (L5%) was quantified by using fast-protein liquid chromatography with an anion-exchange column. Receiver operating characteristic curve analysis was performed to determine cut-off values for L5 levels. The mean L5% and plasma concentration of L5 (ie, [L5]) were significantly higher in patients with HLP or CAD than in healthy adults (P < 0.001). The ranges of L5% and [L5] in healthy adults were determined to be <1.6% and <1.7 mg/dL, respectively. In individuals with L5% >1.6%, the odds ratio was 9.636 for HLP or CAD. In individuals with [L5] >1.7 mg/dL, the odds ratio was 17.684 for HLP or CAD. The power of L5% or [L5] to differentiate patients with HLP or CAD from healthy adults was superior to that of the LDL/high-density lipoprotein ratio. The ranges of L5% and [L5] in healthy adults determined here may be clinically useful in preventing and treating cardiovascular disease.

L5 induces adipose inflammation through LOX-1 by promoting macrophage maturation and infiltration into adipose tissue. Elevated plasma L5 levels may be a novel etiology of adipose tissue inflammation in patients with MetS.

Human bocavirus (HBoV) is a causative agent of respiratory and gastrointestinal diseases worldwide. Four HBoV species (HBoV1-4) have been identified so far. Although a previous report has documented the HBoV association with acute gastroenteritis (AGE) in Taiwan, their epidemiology, genetic diversity, and phylogenetic relationships remain unclear. In this study, we focused on an investigation of these unsolved issues, which will help to reveal molecular epidemiology and phylogeny of the circulating HBoV2 in Taiwan. A total of 176 stool samples were collected from children with AGE for this study. PCR amplification and sequencing on the VP1 gene region were used to identify species. Phylogenetic analysis was conducted by maximum-likelihood and neighbor-joining methods. Selection pressure was also estimated to obtain HBoV evolutionary information. Our results showed the prevalence of HBoV in AGE children was 8.5%, of which HBoV1 was the predominant species (6.3%), followed by HBoV2 (2.3%). Phylogenetic analysis showed those Taiwanese HBoV2 strains have significant genetic variability and can be divided into two clusters. One belongs to HBoV2 genotype A and the other forms an independent unclassified cluster. The nucleotide distance between that independent cluster and the known HBoV2 genotypes was more than 5%, suggesting a new HBoV2 genotype. No positive selection site was found and the virus was under purifying selection. This is the first report to reveal HBoV2 genetic diversity and phylogenetic relationships among AGE children in Taiwan. We find that HBoV2 may have been introduced into the country by multiple origins, and a potential new HBoV2 genotype is proposed.

High-density lipoprotein (HDL) plays a vital role in lipid metabolism and anti-inflammatory activities; a dysfunctional HDL impairs cholesterol efflux pathways. To understand HDL’s role in patients with Alzheimer’s disease (AD), we analyzed the chemical properties and function. HDL from AD patients (AD-HDL) was separated into five subfractions, H1–H5, using fast-protein liquid chromatography equipped with an anion-exchange column. Subfraction H5, defined as the most electronegative HDL, was increased 5.5-fold in AD-HDL (23.48 ± 17.83%) in comparison with the control HDL (4.24 ± 3.22%). By liquid chromatography mass spectrometry (LC/MSE), AD-HDL showed that the level of apolipoprotein (apo)CIII was elevated but sphingosine-1-phosphate (S1P)-associated apoM and anti-oxidative paraoxonase 1 (PON1) were reduced. AD-HDL showed a lower cholesterol efflux capacity that was associated with the post-translational oxidation of apoAI. Exposure of murine macrophage cell line, RAW 264.7, to AD-HDL induced a vibrant expression of ganglioside GM1 in colocalization with apoCIII on lipid rafts alongside a concomitant increase of tumor necrosis factor-α (TNF-α) detectable in the cultured medium. In conclusion, AD-HDL had a higher proportion of H5, an apoCIII-rich electronegative HDL subfraction. The associated increase in pro-inflammatory (apoCIII, TNF-α) components might favor Amyloid β assembly and neural inflammation. A compromised cholesterol efflux capacity of AD-HDL may also contribute to cognitive impairment.

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Background: High-density lipoprotein (HDL), the only lipoprotein class that can cross the blood brain barrier bidirectionally, is positively associated with cognitive functions. To delineate HDL’s role in Alzhenimer’s disease (AD), we analyzed the chemical properties of plasma HDL from AD and healthy normal adult (control) subjects. Methods and results: By using anion-exchange chromatography, we divided HDL into 5 increasingly electronegative subfractions, H1-H5. Compared to the control cohort (4.24±3.22%; n=20), HDL from AD patients (23.48±17.83%; n=30) had a 5.5-fold increase of H5 ( P <0.001; Figure ), accompanied by a decreased protein/lipid ratio attributed to a significant reduction of albumin essential for prevention of amyloid beta (Aβ) aggregation. As determined by LC/MS E and ProteinLynx Global SERVER (PLGS), AD-HDL was had a rich content of apolipoprotein (apo)CIII, but diminished amounts of sphingosine-1-phosphate (S1P)-associated apoM and antioxidative paraoxonase 1 (PON1). Exposure of murine RAW 264.7 macrophages to H5 induced vibrant expression of ganglioside GM1 in colocalization with apoCIII on lipid rafts, alongside a concomitant increase of TNF-α detectable in the cultured medium ( Figure ). LC/MS E examination localized posttranslational oxidation exclusively in ApoA1 residues of H5 in AD-HDL, which exhibited a compromised cholesterol efflux capacity. Conclusions: Plasma HDL from AD patients has a high proportion of H5, an apoCIII-rich electronegative HDL subfraction. The associated reduction in functional (albumin, S1P, apoM) and increase in proinflammatory (apoCIII, PON1, TNF-α) components may favor Aβ assembly and neuroinflammation. Additionally, a compromised cholesterol-efflux capacity of AD-HDL may also contribute to vascular cognitive impairment.

Background: Patients with systemic lupus erythematosus (SLE) are twice more likely to develop cardiovascular disease than the general population, even though their plasma LDL cholesterol (LDL-C) levels are usually not elevated. To delineate the mechanisms, we examined the chemical properties of their LDL. Methods and Results: LDL isolated from SLE patients (LDL-C, 105±33 mg/dL; n=24) exhibited greater mobility in agarose gel electrophoresis than LDL of healthy control subjects (LDL-C, 121±25 mg/dL; n=24), secondary to an increased distribution of L5 (2.30±1.3% vs. 0.7±0.3%; P <0.0001), the most electronegative subfraction of LDL identified by anion-exchange chromatography, in total LDL. CX3CL1 is a membrane-bound chemokine expressed in injured endothelial cells (ECs). CD16 + monocytes are CX3CR1-expressing cells that recognize CX3CL1. Compared with control, SLE patients had a twofold ( P <0.001) increase in CX3CL1 and a threefold ( P <0.0001) increase in CD16 + monocytes in the plasma. Moreover, there was a positive correlation between the CX3CL1 and L5 levels (R=0.45; P <0.018). MALDI/TOF mass spectrometry of the lipid extracted from SLE-LDL revealed a shift from phosphatidylcholines (PCs) to lyso-PCs (LPCs), including m/ z 496.33, 524.36, 537.01, 550.94, when compared with the lipid of control LDL (Figure). The shift was especially prominent in L5. Exposing human aortic ECs to L5 but not normal LDL resulted in a fivefold ( P <0.0001) increase in CX3CL1 expression with concomitant apoptosis. These effects of L5 were significantly attenuated by blocking the platelet-activating receptor, confirming the role of phospholipids in L5’s bioactivity. Conclusions: The increased distribution of LPC-rich electronegative LDL, which induces CX3CL1-CX3CR1 interactions between vascular cells, may contribute to the increased cardiovascular disease prevalence in SLE in the absence of LDL-C elevation.