The association between peptidoglycan recognition protein-1 and coronary and peripheral atherosclerosis: Observations from the Dallas Heart Study

Neutrophil Biomarkers Can Predict Cardiotoxicity of Anthracyclines in Breast Cancer

Doxorubicin (DOX), a commonly used anticancer agent, causes cardiotoxicity that begins with the first dose and may progress to heart failure years after treatment. An inflammatory response associated with neutrophil recruitment has been recognized as a mechanism of DOX-induced cardiotoxicity. This study aimed to validate mRNA expression of the previously identified biomarkers of DOX-induced cardiotoxicity, PGLYRP1, CAMP, MMP9, and CEACAM8, and to assay their protein expression in the peripheral blood of breast cancer patients. Blood samples from 40 breast cancer patients treated with DOX-based chemotherapy were collected before and after the first chemotherapy cycle and > 2 years after treatment. The protein and gene expression of PGLYRP1/Tag7, CAMP/LL37, MMP9/gelatinase B, and CEACAM8/CD66b were determined using ELISA and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of each candidate biomarker. Patients with cardiotoxicity (n = 20) had significantly elevated levels of PGLYRP1, CAMP, MMP9, and CEACAM8 at baseline, after the first dose of DOX-based chemotherapy, and at > 2 years after treatment relative to patients without cardiotoxicity (n = 20). The first dose of DOX induced significantly higher levels of all examined biomarkers in both groups of patients. At > 2 years post treatment, the levels of all but MMP9 dropped below the baseline. There was a good correlation between the expression of mRNA and the target proteins. We demonstrate that circulating levels of PGLYRP1, CAMP, MMP9, and CEACAM8 can predict the cardiotoxicity of DOX. This novel finding may be of value in the early identification of patients at risk for cardiotoxicity.

The microglial innate immune protein PGLYRP1 mediates neuroinflammation and consequent behavioral changes

Peptidoglycan recognition protein 1 (PGLYRP1) is a pattern-recognition protein that mediates antibacterial actions and innate immune responses. Its expression and role in neuroinflammatory conditions remain unclear. We observed the upregulation of PGLYRP1 in inflamed human and mouse spinal cord and brain, with microglia being the primary cellular source. Experiments using a recombinant PGLYRP1 protein show that PGLYRP1 potentiates reactive gliosis, neuroinflammation, and consequent behavioral changes in multiple animal models of neuroinflammation. Furthermore, shRNA-mediated knockdown of Pglyrp1 gene expression attenuates this inflammatory response. In addition, we identify triggering receptor expressed on myeloid cell-1 (TREM1) as an interaction partner of PGLYRP1 and demonstrate that PGLYRP1 promotes neuroinflammation through the TREM1-Syk-Erk1/2-Stat3 axis in cultured glial cells. Taken together, our results reveal a role for microglial PGLYRP1 as a neuroinflammation mediator. Finally, we propose that PGLYRP1 is a potential biomarker and therapeutic target in various neuroinflammatory diseases.

Association of salivary TREM-1 and PGLYRP1 inflammatory markers with non-communicable diseases

AIM

Triggering receptor expressed on myeloid cells 1 (TREM-1) and peptidoglycan recognition protein 1 (PGLYRP1) are elevated in biofluids in the presence of various inflammatory conditions. This cross-sectional study aimed to evaluate the effect of age, sex, smoking and different oral and systemic non-communicable diseases on the levels of TREM-1 and PGLYRP1 in saliva.

MATERIALS AND METHODS

In total, 445 individuals (mean age 48.7 ± 16.9 years, female:male 51%:49%) were included. All provided self-reported information on smoking and systemic diseases and whole stimulated saliva. Periodontal and cariological parameters were recorded. Salivary levels of TREM-1, PGLYRP1 and total protein were measured using commercially available assays.

RESULTS

Salivary TREM-1 levels were significantly higher in stages III-IV periodontitis compared to other periodontal diagnoses (p < .05). Smoking, bleeding on probing (BOP), percentage of pockets ≥4 mm and the number of manifest caries were associated with TREM-1 (p < .05), while sex, BOP, number of manifest caries and muscle and joint diseases were associated with PGLYRP1 (p < .05).

CONCLUSIONS

Salivary TREM-1 is associated with periodontitis and caries, while PGLYRP1 is associated with gingival inflammation and caries. Additionally, TREM-1 levels are modified by smoking, while PGLYRP1 is modified by sex and muscle and joint diseases. TREM-1 and PGLYRP1 in saliva could serve as potential biomarkers for detecting and monitoring non-communicable diseases.

Age of onset defines two distinct profiles of atopic dermatitis in adults

BACKGROUND

The incidence of adult-onset atopic dermatitis (AOAD) is increasing. However, the unique characteristics of AOAD compared to pediatric-onset AD persisting into adulthood (POAD) are underexplored, hampering the development of targeted-therapeutics for this growing population. We thus assessed the profile of AOAD in skin and blood compared to that of POAD.

METHODS

We collected skin biopsies and blood from adults with AOAD, POAD, and healthy controls (n = 15 in each group). Skin samples were analyzed by RNA sequencing, qRT-PCR, and immunohistochemistry, and Olink Proseek multiplex assay was used to identify the serum proteomic profile.

RESULTS

Compared to healthy controls, both AOAD and POAD showed cutaneous immune and barrier dysregulations with a shared Th2/Th22 hyperactivation. Overall, POAD showed greater inflammation in lesional skin, with more prominent expression of Th2/Th17/Th22 markers (CCL17/22, S100A8/9, IL-36A, PI3/Elafin, DEFB4) in POAD compared to AOAD (p-value < .05). In contrast, higher Th1-(IFN-γ, IL-2, IL-15, CCL5) upregulation and Th1-skewing were seen in AOAD. The epidermal barrier was also more compromised in POAD, with greater epidermal hyperplasia and lower expression of markers related to terminal differentiation, lipids, and cell adhesion. In parallel with increased rates of cardiovascular comorbidities, AOAD demonstrated many more significantly dysregulated proteins in serum (n = 148) compared to POAD (n = 86), including pro-inflammatory and cardiovascular-risk markers. Th1-related products showed significant correlations between their skin and blood expressions only in AOAD subjects.

CONCLUSION

Age-of-onset delineates two distinct endophenotypes in adult AD potentially suggesting the need for broader (beyond Th2) therapeutic targeting in AOAD.

Gut microbiome metabolites as key actors in atherosclerosis co-depression disease

Cardiovascular diseases, mainly characterized by atherosclerosis (AS), and depression have a high comorbidity rate. However, previous studies have been conducted under a single disease, and there is a lack of studies in comorbid states to explore the commonalities in the pathogenesis of both diseases. Modern high-throughput technologies have made it clear that the gut microbiome can affect the development of the host's own disorders and have shown that their metabolites are crucial to the pathophysiology of AS and depression. The aim of this review is to summarize the current important findings on the role of gut microbiome metabolites such as pathogen-associated molecular patterns, bile acids, tryptophan metabolites, short-chain fatty acids, and trimethylamine N -oxide in depression and AS disease, with the aim of identifying potential biological targets for the early diagnosis and treatment of AS co-depression disorders.

Association of peptidoglycan recognition protein 1 to post-myocardial infarction and periodontal inflammation: A subgroup report from the PAROKRANK (Periodontal Disease and the Relation to Myocardial Infarction) study

BACKGROUND

Peptidoglycan recognition protein 1 (PGLYRP1) is an antimicrobial and proinflammatory innate immunity protein activated during infections. We aimed to investigate whether PGYLRP1 and associated molecules of the immune response in saliva is a cumulative outcome result of both MI and periodontal inflammation.

METHODS AND RESULTS

Two hundred patients with MI and another 200 matched non-MI controls were included. A full-mouthexamination was conducted to assess periodontal inflammation and collection of stimulated saliva was performed 6 to 10 weeks after the first MI. PGLYRP1, triggering receptor expressed on myeloid cells 1 (TREM-1), interleukin-1 beta (IL-1β) were analyzed by ELISA. Matrix metalloproteinase (MMP)-8 levels were determined by IFMA. Compared to controls, MI patients showed higher salivary PGLYRP1, but not TREM-1 levels. The difference in PGLYRP1 levels remained after adjustment for covariates. In MI patients, the PGLYRP1 levels positively correlated with BOP and PPD 4 to 5 mm. Among non-MI subjects, the levels of PGLYRP1 correlated positively and significantly with BOP and total PPD. Salivary PGLYRP1 concentrations also showed strong positive correlations with levels of TREM-1, IL-1β and MMP-8. In multivariate linear regression analysis, in MI patients, BOP and former smokingstatus displayed an association with salivary PGLYRP1 concentration.

CONCLUSION

MI patients showed higher salivary PGLYRP1 levels than healthy controls, also after adjusting for smoking, sex, age and periodontal health status. Salivary levels of PGLYRP1 may reflect the overall inflammatory burden to chronic bacterial exposure, possibly underpinning the observed associations between periodontitis and exposure with MI.

Prevalence and determinants of atrial fibrillation progression in paroxysmal atrial fibrillation

OBJECTIVE

Atrial fibrillation (AF) often progresses from paroxysmal AF (PAF) to more permanent forms. To improve personalised medicine, we aim to develop a new AF progression risk prediction model in patients with PAF.

METHODS

In this interim-analysis of the Reappraisal of AF: Interaction Between HyperCoagulability, Electrical Remodelling, and Vascular Destabilisation in the Progression of AF study, patients with PAF undergoing extensive phenotyping at baseline and continuous rhythm monitoring during follow-up of ≥1 year were analysed. AF progression was defined as (1) progression to persistent or permanent AF or (2) progression of PAF with >3% burden increase. Multivariable analysis was done to identify predictors of AF progression.

RESULTS

Mean age was 65 (58-71) years, 179 (43%) were female. Follow-up was 2.2 (1.6-2.8) years, 51 of 417 patients (5.5%/year) showed AF progression. Multivariable analysis identified, PR interval, impaired left atrial function, mitral valve regurgitation and waist circumference to be associated with AF progression. Adding blood biomarkers improved the model (C-statistic from 0.709 to 0.830) and showed male sex, lower levels of factor XIIa:C1-esterase inhibitor and tissue factor pathway inhibitor, and higher levels of N-terminal pro-brain natriuretic peptide, proprotein convertase subtilisin/kexin type 9 and peptidoglycan recognition protein 1 were associated with AF progression.

CONCLUSION

In patients with PAF, AF progression occurred in 5.5%/year. Predictors for progression included markers for atrial remodelling, sex, mitral valve regurgitation, waist circumference and biomarkers associated with coagulation, inflammation, cardiomyocyte stretch and atherosclerosis. These prediction models may help to determine risk of AF progression and treatment targets, but validation is needed.

TRIAL REGISTRATION NUMBER

NCT02726698.

Placental Gene Co-expression Network for Maternal Plasma Lipids Revealed Enrichment of Inflammatory Response Pathways

Maternal dyslipidemia during pregnancy has been associated with suboptimal fetal growth and increased cardiometabolic diseasse risk in offspring. Altered placental function driven by placental gene expression is a hypothesized mechanism underlying these associations. We tested the relationship between maternal plasma lipid concentrations and placental gene expression. Among 64 pregnant women from the NICHD Fetal Growth Studies–Singleton cohort with maternal first trimester plasma lipids we extracted RNA-Seq on placental samples obtained at birth. Placental gene co-expression networks were validated by regulatory network analysis that integrated transcription factors and gene expression, and genome-wide transcriptome analysis. Network analysis detected 24 gene co-expression modules in placenta, of which one module was correlated with total cholesterol (r = 0.27, P-value = 0.03) and LDL-C (r = 0.31, P-value = 0.01). Genes in the module (n = 39 genes) were enriched in inflammatory response pathways. Out of the 39 genes in the module, three known lipid-related genes (MPO, PGLYRP1 and LTF) and MAGEC2 were validated by the regulatory network analysis, and one known lipid-related gene (ALX4) and two germ-cell development-related genes (MAGEC2 and LUZP4) were validated by genome-wide transcriptome analysis. Placental gene expression signatures associated with unfavorable maternal lipid concentrations may be potential pathways underlying later life offspring cardiometabolic traits.

Clinical Trial Registration:ClinicalTrials.gov, identifier NCT00912132.

Identification of Key Exosome Gene Signature in Mediating Coronary Heart Disease by Weighted Gene Correlation Network Analysis

Background

Coronary heart disease (CHD) is the most prevalent disease with an unelucidated pathogenetic mechanism and is mediated by complex molecular interactions of exosomes. Here, we aimed to identify differentially expressed exosome genes for the disease development and prognosis of CHD.

Method

Six CHD samples and 32 normal samples were downloaded from the exoRbase database to identify the candidate genes in the CHD. The differentially expressed genes (DEGs) were identified. And then, weighted gene correlation network analysis (WGCNA) was used to investigate the modules in coexpressed genes between CHD samples and normal samples. DEGs and the module of the WGCNA were intersected to obtain the most relevant exosome genes. After that, the function enrichment analyses and protein-protein interaction network (PPI) were performed for the particular module using STRING and Cytoscape software. Finally, the CIBERSORT algorithm was used to analyze the immune infiltration of exosome genes between CHD samples and normal samples.

Result

We obtain a total of 715 overlapping exosome genes located at the intersection of the DEGs and key modules. The Gene Ontology enrichment of DEGs in the blue module included inflammatory response, neutrophil degranulation, and activation of CHD. In addition, protein-protein networks were constructed, and hub genes were identified, such as LYZ, CAMP, HP, ORM1, and LTF. The immune infiltration profiles varied significantly between normal controls and CHD. Finally, we found that mast cells activated and eosinophils had a positive correlation. B cell memory had a significant negative correlation with B cell naive. Besides, neutrophils and mast cells were significantly increased in CHD patients.

Conclusion

The underlying mechanism may be related to neutrophil degranulation and the immune response. The hub genes and the difference in immune infiltration identified in the present study may provide new insights into the diagnostic and provide candidate targets for CHD.

Peptidoglycan Recognition Protein 1 Attenuates Atherosclerosis by Suppressing Endothelial Cell Adhesion

ABSTRACT

Peptidoglycan recognition protein 1 (PGLYRP1) has long been believed to play an important role in infectious and immune diseases. We hypothesized that it might be involved in the pathophysiology of atherosclerotic diseases, which are regarded as chronic inflammatory diseases. Serum PGLYRP1 concentrations were measured in 240 patients with coronary artery disease (CAD) and 209 age-matched and gender-matched individuals with normal coronary arteries using enzyme-linked immunosorbent assay. The expression of PGLYRP1 in atherosclerotic plaques was quantified using western blotting and immunostaining. ApoE-/- mice, fed a high-fat diet, were randomly given intraperitoneal injections of saline or recombinant PGLYRP1 protein for 12 weeks. The effects of PGLYRP1 on human umbilical vein endothelial cells were investigated by western blotting. Higher concentrations of PGLYRP1 were significantly associated with a higher risk of CAD. The odd ratio for upper quartile versus lower quartile was 2.24 (95% confidence interval: 1.21-4.13) after adjustment for sex, age, smoking, body mass index, lipid profile, blood pressure, fasting glucose, and estimated glomerular filtration rate. PGLYRP1 was highly expressed in murine atherosclerotic plaques. Recombinant PGLYRP1 protein alleviated the progress of atherosclerosis in vivo and reduced the expression of endothelial cells' adhesion molecules in vitro. In conclusion, our study suggested that PGLYRP1 is upregulated in patients with CAD and atherosclerotic plaques. PGLYRP1 may participate in the pathophysiological process of atherosclerosis.

Circulating PGLYRP1 Levels as a Potential Biomarker for Coronary Artery Disease and Heart Failure

ABSTRACT

Coronary artery disease (CAD) and associated comorbidities such as heart failure (HF) remain the leading cause of morbidity and mortality worldwide attributed to, at least partially, the lack of biomarkers for efficient disease diagnosis. Here, we evaluated the diagnostic potential of serum peptidoglycan recognition protein 1 (PGLYRP1), an important component of the innate immunity and inflammation system, for both CAD and HF. A machine-learning method (random forest) was used to evaluate the clinical utility of circulating PGLYRP1 for diagnosis of CAD and HF in a total of 370 individuals. Causal links of chronic serum PGLYRP1 elevation to both diseases were further explored in ApoE-/- mice. The serum levels of PGLYRP1 were significantly higher in individuals with either chronic CAD or acute coronary syndrome than those in those without coronary artery stenosis (the control group) and even more pronounced in CAD individuals with concomitant HF. Our random forest classifier revealed that this protein performed better than other recommended clinical indicators in distinguishing the CAD from the control individuals. In addition, this protein associates more with the biomarkers of HF including left ventricular ejection fraction than inflammation. Notably, our mice experiment indicated that long-term treatment with recombinant PGLYRP1 could significantly impair the cardiovascular system as reflected from both increased atherogenic lesions and reduced fractional shortening of the left ventricle. Our findings, therefore, supported the circulating levels of PGLYRP1 as a valuable biomarker for both CAD and HF.

Perinatal granulopoiesis and risk of pediatric asthma

There are perinatal characteristics, such as gestational age, reproducibly associated with the risk for pediatric asthma. Identification of biologic processes influenced by these characteristics could facilitate risk stratification or new therapeutic targets. We hypothesized that transcriptional changes associated with multiple epidemiologic risk factors would be mediators of pediatric asthma risk. Using publicly available transcriptomic data from cord blood mononuclear cells, transcription of genes involved in myeloid differentiation was observed to be inversely associated with a pediatric asthma risk stratification based on multiple perinatal risk factors. This gene signature was validated in an independent prospective cohort and was specifically associated with genes localizing to neutrophil-specific granules. Further validation demonstrated that umbilical cord blood serum concentration of PGLYRP-1, a specific granule protein, was inversely associated with mid-childhood current asthma and early-teen FEV1/FVCx100. Thus, neutrophil-specific granule abundance at birth predicts risk for pediatric asthma and pulmonary function in adolescence.

Salivary Biomarkers of Oral Inflammation Are Associated With Cardiovascular Events and Death Among Kidney Transplant Patients

BACKGROUND

Triggering receptors expressed on myeloid cells (TREMs) and their ligand, peptidoglycan recognition protein 1 (PGLYRP-1), have been detected in secretions from patients with inflammatory diseases, which may lead to the formation of atherosclerotic plaques. Here, we aimed to analyze the association between salivary concentrations of soluble (s)TREM-1 and PGLYRP-1 with death and cardiovascular disease before and after kidney transplantation.

MATERIALS AND METHODS

Saliva samples from 53 patients on dialysis were collected during their regular dental evaluation before treatment and after kidney transplantation. Oral inflammatory burden was assessed from panoramic radiographs and full-mouth dental examination. Demographic data, graft function, patient survival, and history of major cardiovascular events (MACEs) were retrieved from hospital records.

RESULTS

Salivary sTREM-1 before transplantation increased the odds for death and MACE. In addition, PGLYRP-1 increased the odds for MACE before transplantation. After transplantation, neither salivary sTREM-1 nor PGLYRP-1 increased the odds for death or MACE, probably because of the previous eradication of oral inflammatory foci. None of the studied biomarkers correlated with kidney transplant function.

CONCLUSIONS

Salivary sTREM-1 and PGLYRP-1 before transplantation were associated with MACE and death. The utility of salivary proinflammatory biomarkers for risk stratification in kidney transplant candidates requires further investigation.

Cross-sectional study of blood biomarkers of patients with moderate to severe alopecia areata reveals systemic immune and cardiovascular biomarker dysregulation

BACKGROUND

Although there is increased understanding of the alopecia areata (AA) pathogenesis based on studies in scalp tissues, little is known about its systemic profile.

OBJECTIVE

To evaluate the blood proteomic signature of AA and determine biomarkers associated with increased disease severity.

METHODS

In a cross-sectional study, we assessed 350 inflammatory and cardiovascular proteins using OLINK high-throughput proteomics in patients with moderate to severe AA (n = 35), as compared with healthy individuals (n = 36), patients with moderate to severe psoriasis (n = 19), and those with atopic dermatitis (n = 49).

RESULTS

Seventy-four proteins were significantly differentially expressed between AA and control individuals (false discovery rate, <.05) including innate immunity (interleukin [IL] 6/IL-8), T helper (Th) type 1 (interferon [IFN] γ/CXCL9/CXCL10/CXCL11), Th2 (CCL13/CCL17/CCL7), Th17 (CCL20/PI3/S100A12), and cardiovascular-risk proteins (OLR1/OSM/MPO/PRTN3). Eighty-six biomarkers correlated with AA clinical severity (P < .05), including Th1/Th2, and cardiovascular/atherosclerosis-related proteins, including SELP/PGLYRP1/MPO/IL-18/OSM (P < .05). Patients with AA totalis/universalis showed the highest systemic inflammatory tone, including cardiovascular risk biomarkers, compared to control individuals and even to patients with atopic dermatitis and those with psoriasis. The AA profile showed some Th1/Th2 differences in the setting of concomitant atopy.

LIMITATIONS

Our analysis was limited to 350 proteins.

CONCLUSION

This study defined the abnormalities of moderate to severe AA and associated circulatory biomarkers. It shows that AA has systemic immune, cardiovascular, and atherosclerosis biomarker dysregulation, suggesting the need for systemic treatment approaches.

Temporal patterns of macrophage- and neutrophil-related markers are associated with clinical outcome in heart failure patients

AIMS

Evidence on the association of macrophage- and neutrophil-related blood biomarkers with clinical outcome in heart failure patients is limited, and, with the exception of C-reactive protein, no data exist on their temporal evolution. We aimed to investigate whether temporal patterns of these biomarkers are related to clinical outcome in patients with stable chronic heart failure (CHF).

METHODS AND RESULTS

In 263 patients with CHF, we performed serial plasma measurements of scavenger receptor cysteine-rich type 1 protein M130 (CD163), tartrate-resistant acid phosphatase type 5 (TRAP), granulins (GRN), spondin-1 (SPON1), peptidoglycan recognition protein 1 (PGLYRP1), and tissue factor pathway inhibitor (TFPI). The Cardiovascular Panel III (Olink Proteomics AB, Uppsala, Sweden) was used. During 2.2 years of follow-up, we collected 1984 samples before the occurrence of the composite primary endpoint (PE) or censoring. For efficiency, we selected 567 samples for the measurements (all baseline samples, the last two samples preceding the PE, and the last sample before censoring in event-free patients). The relationship between repeatedly measured biomarker levels and the PE was evaluated by joint models. Mean (±standard deviation) age was 67 ± 13 years; 189 (72%) were men; left ventricular ejection fraction (%) was 32 ± 11. During follow-up, 70 (27%) patients experienced the PE. Serially measured biomarkers predicted the PE in a multivariable model adjusted for baseline clinical characteristics [hazard ratio (95% confidence interval) per 1-standard deviation change in biomarker]: CD163 [2.07(1.47-2.98), P < 0.001], TRAP [0.62 (0.43-0.90), P = 0.009], GRN [2.46 (1.64-3.84), P < 0.001], SPON1 [3.94 (2.50-6.50), P < 0.001], and PGLYRP1 [1.62 (1.14-2.31), P = 0.006].

CONCLUSIONS

Changes in plasma levels of CD163, TRAP, GRN, SPON1, and PGLYRP1 precede adverse cardiovascular events in patients with CHF.

Bacterial Peptidoglycan as a Driver of Chronic Brain Inflammation

Peptidoglycan (PGN) is a cell wall component of both Gram-positive and Gram-negative bacteria. Signature fragments of PGN are proinflammatory through engagement of pattern recognition receptors (PRR) on resident tissue cells and circulating leukocytes. Despite its abundance in the gut microbiota, there is limited recognition that PGN could contribute to chronic neuroinflammation. This review highlights current insights into the roles of PGN as a determinant of brain inflammation, notably in multiple sclerosis (MS) and its experimental autoimmune encephalomyelitis (EAE) models. Recent studies demonstrate PGN in blood of healthy adult humans. PGN amplifies autoimmune pathology via activation of innate immune cells. Novel uptake routes through (altered) gut mucosa by myeloid leukocyte subsets promote PGN transport to the brain.

Preliminary study of the urinary proteome in Li and Han ethnic individuals from Hainan

Biomarkers indicate changes associated with disease. Blood is relatively stable due to the homeostatic mechanisms of the body; however, urine accumulates metabolites from changes in the body, making it a better source for early biomarker discovery. The Li ethnic group is a unique minority ethnic group that has only lived on Hainan Island for approximately 5,000 years. Studies have shown that various specific genetic variations are different between the Li and Han ethnic groups. However, whether the urinary proteome between these two ethnic groups is significantly different remains unknown. In this study, differential urinary proteins were identified in the Li and Han ethnic groups using liquid chromatography tandem mass spectrometry (LC-MS/MS). In total, 1,555 urinary proteins were identified. Twenty-five of the urinary proteins were statistically significantly different, 16 of which have been previously reported to be biomarkers of many diseases, and that these significantly different proteins were caused by ethnic differences rather than random differences. Ethnic group differences may be an influencing factor in urine proteome studies and should be considered when human urine samples are used for biomarker discovery.

Pro-inflammatory biomarkers in women with non-obstructive angina pectoris and coronary microvascular dysfunction

Background

Studies that evaluate larger numbers of protein biomarkers in patients with coronary microvascular dysfunction (CMD) have not previously been performed, and very little is known concerning the pathogenetic mechanisms leading to CMD.

Our objective was to analyze associations between a broad cardiovascular disease (CVD) protein biomarker assay and CMD, and further explore internal biomarker relations in order to identify possible targets for future treatment interventions.

Methods

In 174 women with angina pectoris and no significant obstructive coronary artery disease (<50% stenosis on invasive coronary angiography), CMD was assessed by transthoracic Doppler echocardiography measuring coronary flow velocity reserve (CFVR). Blood samples were analyzed with a CVD proteomic panel encompassing 92 biomarkers. The relation between biomarkers and CFVR was evaluated by regression analysis, and possible interrelations between significant biomarkers were investigated by principal component analysis (PCA).

Results

Median age (SD) was 64 years (9.8), median CFVR (IQR) was 2.3 (1.9–2.7), and 28% of patients had CFVR < 2.0. Eighteen biomarkers were significantly correlated with CFVR. In PCA, 8 of the biomarkers significantly related to CFVR showed high loadings on principal component 1 (PC1). The component scores of PC1 were significantly related to CFVR (p = 0.002). The majority of the 8 interrelated PC1 biomarkers were related to the pro-inflammatory TNF-α – IL-6 – CRP pathway.

Conclusion

Eighteen protein biomarkers were significantly associated with CMD. Eight biomarkers were interrelated in PCA, and share connection with pro-inflammatory pathways, highlighting a possible important role of inflammation in CMD.

Human monocyte transcriptional profiling identifies IL-18 receptor accessory protein and lactoferrin as novel immune targets in hypertension

BACKGROUND AND PURPOSE

Monocytes play a critical role in hypertension. The purpose of our study was to use an unbiased approach to determine whether hypertensive individuals on conventional therapy exhibit an altered monocyte gene expression profile and to perform validation studies of selected genes to identify novel therapeutic targets for hypertension.

EXPERIMENTAL APPROACH

Next generation RNA sequencing identified differentially expressed genes in a small discovery cohort of normotensive and hypertensive individuals. Several of these genes were further investigated for association with hypertension in multiple validation cohorts using qRT-PCR, regression analysis, phenome-wide association study and case-control analysis of a missense polymorphism.

KEY RESULTS

We identified 60 genes that were significantly differentially expressed in hypertensive monocytes, many of which are related to IL-1β. Uni- and multivariate regression analyses of the expression of these genes with mean arterial pressure (MAP) revealed four genes that significantly correlated with MAP in normotensive and/or hypertensive individuals. Of these, lactoferrin (LTF), peptidoglycan recognition protein 1 and IL-18 receptor accessory protein (IL18RAP) remained significantly elevated in peripheral monocytes of hypertensive individuals in a separate validation cohort. Interestingly, IL18RAP expression associated with MAP in a cohort of African Americans. Furthermore, homozygosity for a missense single nucleotide polymorphism in LTF that decreases antimicrobial function and increases protein levels (rs1126478) was over-represented in patients with hypertension relative to controls (odds ratio 1.16).

CONCLUSIONS AND IMPLICATIONS

These data demonstrate that monocytes exhibit enhanced pro-inflammatory gene expression in hypertensive individuals and identify IL18RAP and LTF as potential novel mediators of human hypertension.

LINKED ARTICLES

This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

The gut microbiota as a novel regulator of cardiovascular function and disease

The gut microbiome has emerged as a critical regulator of human physiology. Deleterious changes to the composition or number of gut bacteria, commonly referred to as gut dysbiosis, has been linked to the development and progression of numerous diet-related diseases, including cardiovascular disease (CVD). Most CVD risk factors, including aging, obesity, certain dietary patterns, and a sedentary lifestyle, have been shown to induce gut dysbiosis. Dysbiosis is associated with intestinal inflammation and reduced integrity of the gut barrier, which in turn increases circulating levels of bacterial structural components and microbial metabolites that may facilitate the development of CVD. The aim of the current review is to summarize the available data regarding the role of the gut microbiome in regulating CVD function and disease processes. Particular emphasis is placed on nutrition-related alterations in the microbiome, as well as the underlying cellular mechanisms by which the microbiome may alter CVD risk.

Effects of curcumin on the gene expression profile of L-02 cells

Curcumin has been utilized in the treatment and prevention of disease, including cancer and cardiovascular disease, but the molecular mechanism behind such numerous effects remains unclear. To explore the molecular mechanism and action sites of curcumin at the cellular level, human hepatic L-02 cells were used to assess these effects. Microarray technology was employed to detect the gene expression of L-02 cells treated with curcumin. According to the microarray results and the data from the National Center for Biotechnology Information, the present study classified and concluded that these curcumin-sensitive genes were associated with diseases and their signaling pathway. The study supports the evidence for treating cancer and cardiovascular disease, and found certain potential marker genes for conducting systematic research into the effects of curcumin. A total of 80 genes were identified as significantly differentially expressed between samples treated with and without curcumin. Curcumin is capable of developing physiological reactions and functions by regulating the gene expression and affecting its signal transduction pathway. Tumor protein p63, MYC-associated factor X and certain other genes associated with tumors act on a potential therapeutic target, while apolipoprotein B receptor and oxysterol-binding protein-like 7, and their signaling pathways may be involved in the cardioprotective effects of curcumin.

Relationship between SNPs and expression level for candidate genes in rheumatoid arthritis

OBJECTIVES

The study of polymorphisms of genes differentially expressed may lead to the identification of putative causal genetic variants in multifactorial diseases such as rheumatoid arthritis (RA). Based on preceding transcriptomic results, we genotyped 10 single nucleotide polymorphisms (SNPs) belonging to six genes (S100A8, RNASE2, PGLYRP1, RUNX3, IL2RB, and LY96) showing the highest fold change (> 1.9) when level of expression was compared between RA patients and controls. These SNPs were then analysed to evaluate their role in RA.

METHOD

The relationship between gene expression and genotypes of SNPs was first investigated by Kruskal-Wallis and Mann-Whitney tests in RA patients and controls. The genetic association of these SNPs with RA were then analysed using family-based association tests in trio families.

RESULTS

We found that RNASE2 gene expression was related to rs2013109 genotypes in 14 RA patients (p = 0.030). The association study in a discovery sample of 200 French trio families revealed a significant association with RA for one SNP, PGLYRP1-rs2041992 (p = 0.019); this association was stronger in trios where RA patients carried the HLA-DRB1 shared epitope (SE) (p = 0.003). However, this association was not found in a replication sample of 240 European trio families (p = 0.6).

CONCLUSIONS

Family-based association tests did not reveal an association between RA and any SNP of the candidate genes tested. However, RNASE2 gene expression was differentially expressed in RA patients considering a sequence polymorphism. This result led us to highlight the potential disease-specific regulation for this candidate gene in RA.

Associations of visceral and abdominal subcutaneous adipose tissue with markers of cardiac and metabolic risk in obese adults

OBJECTIVE

Visceral (VAT) and abdominal subcutaneous (SAT) adipose tissues contribute to obesity but may have different metabolic and atherosclerosis risk profiles. We sought to determine the associations of abdominal VAT and SAT mass with markers of cardiac and metabolic risk in a large, multiethnic, population-based cohort of obese adults.

DESIGN AND METHODS

Among obese participants in the Dallas Heart Study, we examined the cross-sectional associations of abdominal VAT and SAT mass, assessed by magnetic resonance imaging (MRI) and indexed to body surface area (BSA), with circulating biomarkers of insulin resistance, dyslipidemia, and inflammation (n = 942); and with aortic plaque and liver fat by MRI and coronary calcium by computed tomography (n = 1200). Associations of VAT/BSA and SAT/BSA were examined after adjustment for age, sex, race, menopause, and body mass index.

RESULTS

In multivariable models, VAT significantly associated with the homeostasis model assessment of insulin resistance (HOMA-IR), lower adiponectin, smaller LDL and HDL particle size, larger VLDL size, and increased LDL and VLDL particle number (p < 0.001 for each). VAT also associated with prevalent diabetes, metabolic syndrome, hepatic steatosis, and aortic plaque (p < 0.001 for each). VAT independently associated with C-reactive protein but not with any other inflammatory biomarkers tested. In contrast, SAT associated with leptin and inflammatory biomarkers, but not with dyslipidemia or atherosclerosis. Associations between SAT and HOMA-IR were significant in univariable analyses but attenuated after multivariable adjustment.

CONCLUSION

VAT associated with an adverse metabolic, dyslipidemic, and atherogenic obesity phenotype. In contrast, SAT demonstrated a more benign phenotype, characterized by modest associations with inflammatory biomarkers and leptin, but no independent association with dyslipidemia, insulin resistance, or atherosclerosis in obese individuals. These findings suggest that abdominal fat distribution defines distinct obesity sub-phenotypes with heterogeneous metabolic and atherosclerosis risk.

Discordant effects of rosiglitazone on novel inflammatory biomarkers

BACKGROUND

Although rosiglitazone favorably affects myriad intermediate markers of atherosclerosis, it appears to increase myocardial infarction (MI) risk. We analyzed the effects of rosiglitazone on a panel of 8 novel circulating biomarkers, 4 of which are independently associated with atherosclerosis: lymphotoxin β receptor, peptidoglycan recognition protein 1, chemokine ligand 23, and soluble receptor for advanced glycation end products (sRAGE) as well as on high-sensitivity C-reactive protein (hs-CRP).

METHODS

Blood samples were analyzed at baseline and after 6 months of study treatment from subjects with type 2 diabetes with or at high risk for coronary artery disease in a randomized trial comparing rosiglitazone versus placebo.

RESULTS

Data from 111 subjects (rosiglitazone 55, placebo 56) were analyzed. Mean age was 56 years, 41% were women, and 66% were nonwhite. Compared with baseline values, rosiglitazone adversely affected levels of lymphotoxin β receptor (1.7 vs 2.4 ng/mL, P = .002), peptidoglycan recognition protein 1 (29.0 vs 30.1 ng/mL, P = .01), and chemokine ligand 23 (0.76 vs 0.84 ng/mL, P = .02) and favorably affected levels of sRAGE (inversely associated with atherosclerosis, 1.1 vs 1.4 ng/mL, P = .003) and hs-CRP (0.42 vs 0.31 ng/mL, P = .02); no changes were observed with rosiglitazone in the other biomarkers. In the placebo group, change was observed only for sRAGE (1.0 vs 1.1 ng/mL, P = .046).

CONCLUSION

Rosiglitazone adversely affected 3 novel biomarkers and favorably affected a fourth previously associated with atherosclerosis while improving hs-CRP, as has previously been shown. Whether these complex effects on circulating inflammatory biomarkers contribute to the signal of increased MI risk with rosiglitazone and whether pioglitazone has similar effects warrant further investigation.

Soluble ST2 Is Associated with All-Cause and Cardiovascular Mortality in a Population-Based Cohort: The Dallas Heart Study

BACKGROUND

ST2, part of the interleukin-1 receptor family, is released from cardiac myocytes under mechanical strain. Soluble ST2 (sST2) concentrations are associated with adverse cardiac events in high-risk cohorts. We evaluated the association of sST2 with all-cause and cardiovascular mortality in a large, low-risk population–based cohort.

METHODS

Plasma sST2 was measured in 3294 subjects from the Dallas Heart Study, a probability-based population cohort. We categorized participants into undetectable (reference group) or quartiles of detectable sST2 concentrations. Associations with all-cause and cardiovascular mortality were assessed over a median 8.3 years of follow-up.

RESULTS

sST2 concentrations were not significantly associated with most traditional risk factors, prevalent subclinical cardiovascular disease, or nonfatal cardiac events. However, a higher proportion of African Americans had detectable concentrations of sST2 than non–African Americans (44% vs 21%, respectively, P &lt; 0.0001). In addition, sST2 concentrations were significantly associated with markers of inflammation. Increased sST2 was associated with increased all-cause mortality (Ptrend ≤ 0.0001) and cardiovascular mortality (Ptrend = 0.0004). In fully adjusted models, those in the highest quartile of detectable sST2 were at increased risk for all-cause death compared to those with undetectable sST2 concentrations (adjusted hazard ratio 2.1, 95% CI 1.4–3.2, P = 0.0009).

CONCLUSIONS

In a low-risk population, sST2 does not associate with traditional cardiovascular risk factors or nonfatal cardiovascular events but is higher in African Americans and is associated with increased all-cause and cardiovascular mortality. Further investigation is needed regarding the role of sST2 in risk prediction, particularly among African Americans.

Genetic and phylogenetic evidence for horizontal gene transfer among ecologically disparate groups of marine Vibrio

Vibrio represents a diverse bacterial genus found in different niches of the marine environment, including numerous genera of marine sponges (phylum Porifera), inhabiting different depths and regions of benthic seas, that are potentially important in driving adaptive change among Vibrio spp. Using 16S rRNA gene sequencing, a previous study showed that sponge-derived (SD) vibrios clustered with their mainstream counterparts present in shallow, coastal ecosystems, suggesting a genetic relatedness between these populations. Sequences from the topA, ftsZ, mreB, rpoD, rctB and toxR genes were used to investigate the degree of relatedness existing between these two separate populations by examining their phylogenetic and genetic disparity. Phylogenies were constructed from the concatenated sequences of the six housekeeping genes using maximum-parsimony, maximum-likelihood and neighbour-joining algorithms. Genetic recombination was evaluated using the incongruence length difference test, Split decomposition and measuring overall compatibility of sites. This combined technical approach provided evidence that SD Vibrio strains are largely genetically homologous to their shallow-water counterparts. Moreover, the analyses conducted support the existence of extensive horizontal gene transfer between these two groups, supporting the idea of a single panmictic population structure among vibrios from two seemingly distinct, marine environments.

Dysfunctional adiposity and the risk of prediabetes and type 2 diabetes in obese adults

CONTEXT

The risk of type 2 diabetes mellitus is heterogeneous among obese individuals. Factors that discriminate prediabetes or diabetes risk within this population have not been well characterized. A dysfunctional adiposity phenotype, characterized by excess visceral fat and insulin resistance, may contribute to diabetes development in those with obesity.

OBJECTIVE

To investigate associations between adiposity phenotypes and risk for incident prediabetes and diabetes in a multiethnic, population-based cohort of obese adults.

DESIGN, SETTING, AND PARTICIPANTS

Among 732 obese participants (body mass index ≥30) aged 30 to 65 years without diabetes or cardiovascular disease enrolled between 2000 and 2002 in the Dallas Heart Study, we measured body composition by dual energy x-ray absorptiometry and magnetic resonance imaging (MRI); circulating adipokines and biomarkers of insulin resistance, dyslipidemia, and inflammation; and subclinical atherosclerosis and cardiac structure and function by computed tomography and MRI.

MAIN OUTCOME MEASURES

Incidence of diabetes through a median 7.0 years (interquartile range, 6.6-7.6) of follow-up. In a subgroup of 512 participants with normal fasting glucose values at baseline, incidence of the composite of prediabetes or diabetes was determined.

RESULTS

Of the 732 participants (mean age, 43 years; 65% women; 71% nonwhite), 84 (11.5%) developed diabetes. In multivariable analysis, higher baseline visceral fat mass (odds ratio [OR] per 1 SD [1.4 kg], 2.4; 95% CI, 1.6-3.7), fructosamine level (OR per 1 SD [1.1 μmol/L], 2.0; 95% CI, 1.4-2.7), fasting glucose level (OR per 1 SD [1.1 μmol/L], 1.9; 95% CI, 1.4-2.6), family history of diabetes (OR, 2.3; 95% CI, 1.3-4.3), systolic blood pressure (OR per 10 mm Hg, 1.3; 95% CI, 1.1-1.5), and weight gain over follow-up (OR per 1 kg, 1.06; 95% CI, 1.02-1.10) were independently associated with diabetes, with no associations observed for body mass index, total body fat, or abdominal subcutaneous fat. Among the 512 participants with normal baseline glucose values, the composite outcome of prediabetes or diabetes occurred in 39.1% and was independently associated with baseline measurements of visceral fat mass; levels of fasting glucose, insulin, and fructosamine; older age; nonwhite race; family history of diabetes; and weight gain over follow-up (P < .05 for each) but not with measurements of general adiposity.

CONCLUSION

Excess visceral fat and insulin resistance, but not general adiposity, were independently associated with incident prediabetes and type 2 diabetes mellitus in obese adults.

Race-specific associations of myeloperoxidase with atherosclerosis in a population-based sample: the Dallas Heart Study

OBJECTIVE

Myeloperoxidase (MPO) is a leukocyte-derived enzyme that appears to be directly involved in atherosclerosis development. We evaluated the association of circulating MPO with coronary and aortic atherosclerosis in a large, multiethnic population.

METHODS AND RESULTS

Plasma levels of MPO were measured in 3294 subjects participating in the Dallas Heart Study, a probability-based population sample. Coronary artery calcification (CAC) was measured by EBCT, and abdominal aorta plaque prevalence (AP) and burden (APB), as well as abdominal aorta wall thickness (AWT) were determined by MRI. Associations between MPO and atherosclerosis phenotypes were assessed in multivariable analyses adjusting for traditional atherosclerosis risk factors. MPO levels in the 4th compared with 1st quartile independently associated with prevalent AP (OR 1.41, 95% CI 1.08-1.84), APB (beta coefficient 0.23, p = 0.02), and AWT (beta coefficient 0.04, p = 0.03), but not with prevalent CAC (OR 0.84, 95% CI 0.61-1.17). MPO remained associated with aortic atherosclerosis phenotypes but not coronary calcification after adjustment for other inflammatory biomarkers. A significant interaction was observed between race/ethnicity, MPO and AP (p(interaction) = 0.038), such that MPO levels in the 4th vs 1st quartile associated with prevalent AP in African Americans, (OR 1.81, 95% CI 1.23-2.65) but not in White or Hispanic participants (OR 0.99, 95% CI 0.68-1.44).

CONCLUSION

Higher levels of MPO associated with aortic but not coronary atherosclerosis, with significant associations limited to African American participants. These findings suggest that MPO might be a novel risk factor contributing to racial disparities in peripheral vascular disease.

Associations of four circulating chemokines with multiple atherosclerosis phenotypes in a large population-based sample: results from the dallas heart study

Specific chemokines contribute to vascular inflammation and may be useful biomarkers to detect atherosclerosis. The chemokines CXCL1 and CCL11 have previously been studied in animal or human models of atherosclerosis, while CXCL2 and CCL23 have not. Among 2,454 subjects enrolled in the Dallas Heart Study, a multi-ethnic population-based sample, we measured plasma CCL11, CCL23, CXCL1, and CXCL2, and associated levels with coronary artery calcium (CAC) by computed tomography, and aortic wall thickness, plaque burden, and compliance by magnetic resonance imaging. Elevated chemokine levels were defined as greater than or equal to the median for CCL11 and CCL23 and greater than or equal to the upper detection limit for CXCL1 and CXCL2. Elevated CCL23 (P < 0.01) and CXCL1 (P = 0.01), but not CCL11 and CXCL2, associated with CAC in univariable analyses. After adjustment for traditional risk factors, elevated CCL23 remained associated with CAC (OR 1.3, 95% CI 1.0-1.7; P = 0.02), while the association with CXCL1 was modestly attenuated (OR 1.4, 95% CI 1.0-2.1; P = 0.06). CCL23 also associated with aortic wall thickness, plaque, and compliance in univariable analyses (P < 0.05 for each), but these associations were attenuated after multivariable adjustment. The novel chemotactic protein, CCL23, which has not been previously studied in atherosclerosis, is independently associated with coronary atherosclerosis, suggesting that this chemokine merits further study in animal and human models.

Circulating lymphotoxin β receptor and atherosclerosis: observations from the Dallas Heart Study

OBJECTIVE

Lymphotoxin β receptor (LTβR), a member of the tumor necrosis factor superfamily, binds ligands expressed by activated lymphocytes. Interruption of LTβR signaling improves autoimmune diseases and alters lipid homeostasis. We assayed circulating LTβR and examined its association with atherosclerosis phenotypes in a population-based sample.

METHODS AND RESULTS

Plasma LTβR was measured by ELISA in 3215 subjects enrolled in the Dallas Heart Study. Atherosclerosis was assessed using CT measurements of coronary calcium (CAC) and abdominal MRI measurements of aortic plaque (AP) (n=2252) and aortic wall thickness (AWT) (n=2265). We analyzed associations between LTβR and atherosclerosis using multivariable logistic and linear regression methods. Higher levels of LTβR associated with most traditional cardiovascular risk factors, multiple inflammatory markers, and markers of cardiac injury. Univariable analyses demonstrated significant associations of LTβR with CAC, AP, and AWT (p<0.0001 for each). In multivariable models adjusted for traditional risk factors, the 4th vs. the 1st quartile of LTβR remained associated with prevalent CAC, AP, and increased AWT (all p<0.05). Similar associations were observed when LTβR was modeled as a log-transformed continuous variable.

CONCLUSION

LTβR levels are independently associated with atherosclerosis in multiple vascular beds. These findings support further investigation of the lymphotoxin/LTβR pathway in atherosclerosis.

Review: Mammalian peptidoglycan recognition proteins (PGRPs) in innate immunity

Peptidoglycan recognition proteins (PGRPs or PGLYRPs) are innate immunity proteins that are conserved from insects to mammals, recognize bacterial peptidoglycan, and function in antibacterial immunity and inflammation. Mammals have four PGRPs - PGLYRP1, PGLYRP2, PGLYRP3, and PGLYRP4. They are secreted proteins expressed in polymorphonuclear leukocytes (PGLYRP1), liver (PGLYRP2), or on body surfaces, mucous membranes, and in secretions (saliva, sweat) (PGLYRP3 and PGLYRP4). All PGRPs recognize bacterial peptidoglycan. Three PGRPs, PGLYRP1, PGLYRP3, and PGLYRP4 are directly bactericidal for both Gram-positive and Gram-negative bacteria and have no enzymatic activity, whereas PGLYRP2 is an N-acetylmuramoyl-L-alanine amidase that hydrolyzes bacterial cell wall peptidoglycan. Peptidoglycan recognition proteins influence host- pathogen interactions not only through their antibacterial or peptidoglycan-hydrolytic properties, but also through their pro-inflammatory and anti-inflammatory properties that are independent of their hydrolytic and antibacterial activities. The PGRPs likely play a role both in antibacterial defenses and several inflammatory diseases. They modulate local inflammatory responses in tissues (such as arthritic joints) and there is evidence for association of PGRPs with inflammatory diseases, such as psoriasis.

Postmenopausal estrogen and progestin effects on the serum proteome

Background

Women's Health Initiative randomized trials of postmenopausal hormone therapy reported intervention effects on several clinical outcomes, with some important differences between estrogen alone and estrogen plus progestin. The biologic mechanisms underlying these effects, and these differences, have yet to be fully elucidated.

Methods

Baseline serum samples were compared with samples drawn 1 year later for 50 women assigned to active hormone therapy in both the estrogen-plus-progestin and estrogen-alone randomized trials, by applying an in-depth proteomic discovery platform to serum pools from 10 women per pool.

Results

In total, 378 proteins were quantified in two or more of the 10 pooled serum comparisons, by using strict identification criteria. Of these, 169 (44.7%) showed evidence (nominal P < 0.05) of change in concentration between baseline and 1 year for one or both of estrogen-plus-progestin and estrogen-alone groups. Quantitative changes were highly correlated between the two hormone-therapy preparations. A total of 98 proteins had false discovery rates < 0.05 for change with estrogen plus progestin, compared with 94 for estrogen alone. Of these, 84 had false discovery rates <0.05 for both preparations. The observed changes included multiple proteins relevant to coagulation, inflammation, immune response, metabolism, cell adhesion, growth factors, and osteogenesis. Evidence of differential changes also was noted between the hormone preparations, with the strongest evidence in growth factor and inflammation pathways.

Conclusions

Serum proteomic analyses yielded a large number of proteins similarly affected by estrogen plus progestin and by estrogen alone and identified some proteins and pathways that appear to be differentially affected between the two hormone preparations; this may explain their distinct clinical effects.

Differential associations between soluble cellular adhesion molecules and atherosclerosis in the Dallas Heart Study: a distinct role for soluble endothelial cell-selective adhesion molecule

OBJECTIVE

Endothelial cell-selective adhesion molecule (ESAM) is a junctional-type cellular adhesion molecule (CAM) that is uniquely expressed in vascular endothelium and activated platelets and mediates neutrophil and monocyte diapedesis across the endothelium. Given its role in endothelial pathobiology, we hypothesized that soluble ESAM (sESAM) would be independently associated with atherosclerosis and vascular stiffness.

METHODS AND RESULTS

We measured sESAM, soluble intercellular adhesion molecule (sICAM)-1, and soluble vascular cell adhesion molecule (sVCAM)-1 in 3222 subjects participating in the Dallas Heart Study, a probability-based population sample. Coronary artery calcium (CAC) was measured by electron beam computed tomography, and abdominal aortic wall thickness (AWT), aortic plaque burden (APB), and aortic compliance (AC) by MRI. Increasing levels of sESAM were associated with all major cardiovascular risk factors as well as with inflammatory markers such as monocyte chemoattractant protein-1, but only weakly correlated with sICAM-1 and sVCAM-1. In multivariate analyses, sESAM was independently associated with prevalent CAC (OR 1.2 per SD increase, 95% CI 1.1 to 1.3; P=0.005), AWT (P=0.035), and AC (P=0.006), but not APB (P=0.15). In contrast, no independent associations were observed between sICAM-1 or sVCAM-1 and any of the atherosclerosis phenotypes.

CONCLUSIONS

In this first reported clinical study of sESAM in humans, sESAM levels were independently associated with CAC, AWT, and AC, whereas sICAM-1 and sVCAM-1 were not. These findings support a unique role of this cellular adhesion molecule in atherosclerosis and suggest the need for further exploration of sESAM as a predictive biomarker and potential mediator of atherosclerosis.

Relationship of oxidized phospholipids on apolipoprotein B-100 particles to race/ethnicity, apolipoprotein(a) isoform size, and cardiovascular risk factors: results from the Dallas Heart Study

BACKGROUND

Elevated levels of oxidized phospholipids (OxPLs) on apolipoprotein B-100 particles (OxPL/apoB) are associated with cardiovascular disease and predict new cardiovascular events. Elevated lipoprotein (a) [Lp(a)] levels are a risk factor for cardiovascular disease in whites and also in blacks if they carry small apolipoprotein(a) [apo(a)] isoforms. The relationship of OxPL/apoB levels to race/ethnicity, cardiovascular risk factors, and apo(a) isoforms is not established.

METHODS AND RESULTS

OxPL/apoB levels were measured in 3481 subjects (1831 black, 1047 white, and 603 Hispanic subjects) in the Dallas Heart Study and correlated with age, sex, cardiovascular risk factors, and Lp(a) and apo(a) isoforms. Significant differences in OxPL/apoB levels were noted among racial/ethnic subgroups, with blacks having the highest levels compared with whites and Hispanics (P<0.001 for each comparison). OxPL/apoB levels generally did not correlate with age, sex, or risk factors. In the overall cohort, OxPL/apoB levels strongly correlated with Lp(a) (r=0.85, P<0.001), with the shape of the relationship demonstrating a "reverse L" shape for log-transformed values. The highest correlation was present in blacks, followed by whites and Hispanics; was dependent on apo(a) isoform size; and became progressively weaker with larger isoforms. The size of the major apo(a) isoform (number of kringle type IV repeats) was negatively associated with OxPL/apoB (r=-0.49, P<0.001) and Lp(a) (r=-0.61, P<0.001) regardless of racial/ethnic group. After adjustment for apo(a) isoform size, the relationship between OxPL/apoB and Lp(a) remained significant (r=0.67, P<0.001).

CONCLUSIONS

OxPL/apoB levels vary according to race/ethnicity, are largely independent of cardiovascular risk factors, and are inversely associated with apo(a) isoform size. The association of OxPL with small apo(a) isoforms, in which a similar relationship is present among all racial/ethnic subgroups despite differences in Lp(a) levels, may be a key determinant of cardiovascular risk.