Background: The discovery and development of novel biomarkers that could facilitate early diagnosis and thus prevent the progression of atherosclerosis-related diabetes mellitus (DM), cerebral infarction (CI), and cardiovascular disease (CVD) has garnered much research interest. Notably, recent reports have described a number of highly sensitive antibody markers. In this study, we aimed to identify additional antibody markers that would facilitate screening. Methods:The amplified luminescent proximity homogeneous assay (AlphaLISA) method, which incorporates glutathione-or streptavidin-donor beads and anti-human-IgG-acceptor beads, was used to evaluate serum antibody levels in serum samples. The protein array method was used for the initial screening, and peptide arrays were used to identify epitope sites. Results:The protein array identified SH3 domain-binding protein 5 (SH3BP5) as a target antigen of serum IgG antibodies in the sera of patients with atherosclerosis. We prepared recombinant glutathione S-transferase (GST)-fused SH3BP5 protein. Peptide arrays revealed that the epitope site recognized by serum antibodies is located within amino acids 161-174 of SH3BP5. AlphaLISA revealed significantly higher serum antibody levels against both the SH3BP5 protein and peptide in patients with DM, acute-phase CI, transient ischemic attack, CVD or chronic kidney disease (CKD), than in healthy donors. Furthermore, areas under the receiver operating characteristic curves of these antibodies were higher in patients with CKD and DM than in other patients. Spearman correlation analysis revealed associations between the serum antibody levels against SH3BP5 peptide and artery stenosis, hypertension, and smoking. Conclusions:The serum anti-SH3BP5 antibody marker appears to be useful for estimating the progress of atherosclerosis and may discriminate atherosclerosis associated with hypertension and/or habitual smoking.

Transient ischemic attack (TIA) is a predictor for cerebral infarction (CI), and early diagnosis of TIA is extremely important for the prevention of CI. We set out to identify novel antibody biomarkers for TIA and CI, and detected matrix metalloproteinase 1 (MMP1), chromobox homolog 1 (CBX1), and chromobox homolog 5 (CBX5) as candidate antigens using serological identification of antigens by recombinant cDNA expression cloning (SEREX) and Western blotting to confirm the presence of serum antibodies against the antigens. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) revealed that serum antibody levels were significantly higher in patients with TIA or acute-phase CI (aCI) compared with healthy donors (P < 0.01). Spearman’s correlation analysis and multivariate logistic regression analysis demonstrated that levels of anti-MMP1, anti-CBX1, and anti-CBX5 antibodies were associated with age, cigarette-smoking habits, and blood pressure. Thus, serum levels of antibodies against MMP1, CBX1, and CBX5 could potentially serve as useful tools for diagnosing TIA and predicting the onset of aCI.

Cerebral infarction (CI), cardiovascular disease (CVD), diabetes mellitus (DM) and chronic kidney disease (CKD) are atherosclerosis-related diseases, which are major causes of health damage. For early and sensitive diagnosis, development of novel biomarkers is expected and of significant practical importance. First screening was carried out by phage expression cloning to identify antigen proteins recognized by serum IgG antibodies in patients with atherosclerosis. RPA2, LRPAP1, EEF1A1, SPOCK1, LOC729260, tubulin beta 2C (TUBB2C) and KIAA0020 markers were identified. We then compared the serum antibody levels against the candidate proteins between healthy donors (HD) and patients with CI, CVD, DM, or CKD by Alpha (amplified luminescent proximity homogeneous assay)-LISA method. The results showed that the serum TUBB2C antibody levels were significantly higher in patients with CI, DM, or CKD than those in HD. Using the average + 2SD of HD as the cut-off value, the positive thresholds of TUBB2C antibody markers were 14.8% in CI, 25.8% in DM, and 18.3% in CKD. TUBB2C antibody levels were well correlated with artery stenosis degrees such as plaque score, maximum intima-media thickness and cardio ankle vascular index. Consequently, TUBB2C antibody markers are useful to diagnose atherosclerosis, DM, and CKD, and can be applied to the prediction of the onset of CI. The serum anti-TUBB2C antibody markers are useful for the diagnosis of DM and CKD.

Adiponectin secreted from the adipocytes plays pleiotropic, anti-atherosclerotic roles, such as enhancement of insulin secretion and an increase in energy expenditure. The measurement of levels of circulating adiponectin is useful to evaluate the progression of atherosclerosis-related diseases, such as coronary artery disease (CAD), cerebral infarction (CI) and diabetes mellitus (DM). We examined the serum antibody levels against recombinant adiponectin protein via the amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) method. The results revealed that the antibody levels were significantly higher in patients with CAD, CI and type 2 DM, than in healthy donors. Receiver operating curve analysis showed that the sensitivity was in a range of 41–48% for CAD, CI and DM. Thus, the serum anti-adiponectin antibody levels could be a common marker for atherosclerosis-related diseases.

Background: Atherosclerosis-related life-style diseases such as cerebral infarction (CI), cardiovascular disease (CVD), diabetes mellitus (DM), and chronic kidney disease (CKD) are a serious problem in the recently aging society. The development of novel and sensitive diagnostic markers is necessary and expected for the early treatment. Methods and Results: Through the first screening by phage expression cloning, we identified ATPase, Ca ++ transporting, plasma membrane 4 (ATP2B4) and bone morphogenetic protein 1 (BMP-1) as antigens recognized by IgG antibodies in the sera of patients with atherosclerosis. The presence of autoantibodies against these antigens in serum specimens was confirmed by Western blotting. We then compared serum antibody levels against recombinant ATP2B4 and BMP-1 proteins between healthy donors (HD) and patients with atherosclerotic diseases, such as CI, transient ischemic attack (TIA), CVD, DM, or CKD, by the Alpha (amplified luminescent proximity homogeneous assay)-LISA method. The results revealed that both antibody levels were significantly higher in patients with these diseases than in HD and exhibited most prominent differences in CKD vs. HD. Correlation analysis showed that both antibody levels were well correlated with the degree of artery stenosis, such as maximum intima-media thickness with some different patterns, i.e., anti-ATP2B4 antibody levels were related to hypertension, whereas anti-BMP-1 antibodies were related to smoking habits. Conclusions:The serum antibody levels against ATP2B4 and BMP-1 can be useful diagnostic markers for atherosclerosis and its related diseases caused by hypertension and smoking habits, respectively.