The future of protein biomarker research in type 2 diabetes mellitus

Introduction: The onset of type 2 diabetes mellitus (T2DM) is strongly associated with obesity and subsequent perturbations in immuno-metabolic responses. To understand the complexity of these systemic changes and better monitor the health status of people at risk, validated clinical biomarkers are needed. Omics technologies are increasingly applied to measure the interplay of genes, proteins and metabolites in biological systems, which is imperative in understanding molecular mechanisms of disease and selecting the best possible molecular biomarkers for clinical use.

Areas covered: This review describes the complex onset of T2DM, the contribution of obesity and adipose tissue inflammation to the T2DM disease mechanism, and the output of current biomarker strategies. A new biomarker approach is described that combines published and new self-generated data to merge multiple -omes (i.e. genome, proteome, metabolome etc.) toward understanding of mechanism of disease on the individual level and design multiparameter biomarker panels that drive significant impacts on personalized healthcare.

Expert commentary: We here propose an approach to use cross-omics analyses to contextualize published biomarker data and better understand molecular mechanisms of health and disease. This will improve the current and future innovation gaps in translation of discovered putative biomarkers to clinically applicable biomarker tests.     

Circulating miRNA-33: a potential biomarker in patients with coronary artery disease

Background: Circulating microRNAs (miRNA) are present in body fluids in stable, cell-free form. Likewise, these miRNAs can be identified in various stages of coronary artery disease (CAD) such as inflammation, endothelial dysfunction, proliferation and atherosclerosis among others. miRNA expression levels can be identified.

Aims and objectives: To determine the expression of circulating miRNAs (miR-126, miR-92, miR-33, miR-145 and miR-155) in CAD patients of Indian origin.

Material and methods: miRNA profiling analysis in blood plasma was performed by quantitative real-time-PCR (qRT-PCR) in 60 angiographically verified subjects including 30 CAD patients and 30 age- and gender-matched controls. Association between the expression of all five circulating miRNAs and clinical characteristics of patients with CAD were analysed using Medcalc statistics. The severity of CAD was assessed using SYNTAX score (SS).

Results: Expression of plasma miR-33 increased by 2.9 folds in CAD patients than in control group (p value ≥0.002) also it was found that miR-33 expression levels in mild cases (SS: ≤22) were significantly higher than CAD controls. There was a modest negative correlation between miR-33 and total cholesterol/high density lipoprotein ratio, triglycerides and very low density lipoprotein.

Conclusion: The study reports a significant association between increased levels of plasma miR-33 and CAD. Thus, plasma miR-33 appears to be a promising non-invasive biomarker, but requires further validation in a large cohort.     

Identification of biomarker panels as predictors of severity in coronary artery disease

Matrix metalloproteinases (MMPs) are implicated in atherosclerotic plaque rupture and recondition. Specific tissue inhibitors (TIMPs) control MMP functions. Both MMPs and TIMPs are potential biomarkers of plaque instability. Elevated Apo-CII and CIII and Apo-E levels are recognized as cardiovascular disease risk factors. We aimed to establish the best blood biomarker panel to evaluate the coronary artery disease (CAD) severity. Plasma levels of MMP-3 and MMP-9, TIMP-1 and TIMP-2, Apo-CII, Apo-CIII and Apo-E were measured in 472 patients with CAD evaluated by coronary angiography and electrocardiography, and in 285 healthy controls. MMP-3 and MMP-9 plasma levels in CAD patients were significantly increased (P < 0.001) compared to controls (3.54- and 3.81-fold, respectively). Furthermore, these increments are modulated by CAD severity as well as for Apo-CII and Apo-CIII levels (P < 0.001). TIMPs levels were decreased in CAD versus controls (P < 0.001) and in inverse correlation to MMPs. Standard ROC curve approach showed the importance of panels of biomarkers, including MMP-3, MMP-9, TIMP-1, TIMP-2, Apo-CII and Apo-CIII, for disease aggravation diagnosis. A high area under curve (AUC) value (0.995) was reached for the association of MMP-9, TIMP-2 and Apo-CIII. The unbalance between MMPs and TIMPs in vascular wall and dyslipidaemia creates favourable conditions for plaque disruption. Our study suggests that the combination of MMP-9, TIMP-2 and Apo-CIII values (‘CAD aggravation panel’) characterizes the severity of CAD, that is electrophysiological state, number of involved vessels, stent disposal and type of stent.     

Clinical significance of circulating microRNAs as diagnostic biomarkers for coronary artery disease

Coronary artery disease (CAD) is one of the biggest threats to human life. Circulating microRNAs (miRNAs) have been reported to be linked to the pathogenesis of CAD, indicating the possible role in CAD diagnosis. The present study aimed to explore the expression profile of plasma miRNAs and estimate their value in diagnosis for CAD. 67 Non‐CAD control subjects and 88 CAD patients were enrolled. We conducted careful evaluation by RT‐PCR analysis, Spearman rank correlation coefficients analysis, Receiver Operating Characteristic (ROC) curves analysis and so on. The plasma levels of six miRNAs known to be related to CAD were measured and three of them showed obvious expression change. Circulating miR‐29a‐3p, miR‐574‐3p and miR‐574‐5p were all significantly increased. ROC analysis revealed the probability of the three miRNAs as biomarkers with AUCs (areas under the ROC curve) of 0.830, 0.792 and 0.789, respectively. They were significantly correlated with each other in CAD patients, suggesting the possibility of joint diagnosis. The combined AUC was 0.915, much higher than each single miRNA. Therefore, our study revealed three promising biomarkers for early diagnosis of CAD. The combination of these miRNAs may act more effectively than individual ones for CAD diagnosis.     

Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine as a biomarker in type 2 diabetes

The increasing prevalence of diabetes together with the associated morbidity and mortality calls for additional preventive and therapeutic strategies. New biomarkers that can be used in therapy control and risk stratification as alternatives to current methods are needed and can facilitate a more individualized and sufficient treatment of diabetes. Evidence derived from both epidemiological and mechanistic studies suggests that oxidative stress has an important role in mediating the pathologies of diabetic complications. A marker of intracellular oxidative stress that potentially could be used as a valuable biomarker in diabetes is the DNA oxidation marker 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), which can be assessed noninvasively in the urine, with minimal discomfort for the patient. In this review the analytical validity of 8-oxodG is addressed by highlighting important methodological issues. The available epidemiological evidence regarding urinary 8-oxodG and type 2 diabetes is presented. A possible role for DNA oxidation in cancer development in type 2 diabetes patients is discussed, followed by an evaluation of the potential of urinary 8-oxodG as a clinical biomarker in type 2 diabetes.     

Circulating microRNA-1 as a potential novel biomarker for acute myocardial infarction

Recent studies have revealed the role of microRNAs (miRNAs) in a variety of basic biological and pathological processes and the association of miRNA signatures with human diseases. Circulating miRNAs have been proposed as sensitive and informative biomarkers for multiple cancers diagnosis. We have previously documented aberrant up-regulation of miR-1 expression in ischemic myocardium and the consequent slowing of cardiac conduction. However, whether miR-1 could be a biomarker for predicting acute myocardial infarction (AMI) is unclear. In the present study, we recruited 159 patients with or without AMI for quantification of miR-1 level in plasma using real-time RT-PCR method. We performed Wilcoxon rank sum and signed rank tests for comparison. Univariable linear regression and logistics regression analyses were performed to assess the potential correlation between miR-1 and known AMI markers. We also conducted receiver-operator characteristic curve (ROC) analysis to evaluate the diagnostic ability of miR-1. We found that: miR-1 level was significantly higher in plasma from AMI patients compared with non-AMI subjects and the level was dropped to normal on discharge following medication. Increased circulating miR-1 was not associated with age, gender, blood pressure, diabetes mellitus or the established biomarkers for AMI. However, miR-1 level was well correlated with QRS by both univariable linear and logistics regression analyses. The area under ROC curve (AUC) was 0.7740 for separation between non-AMI and AMI patients and 0.8522 for separation AMI patients under hospitalization and discharge. Collectively, our results revealed that circulating miR-1 may be a novel, independent biomarker for diagnosis of AMI.     

Plasma fatty acid metabolic profile coupled with uncorrelated linear discriminant analysis to diagnose and biomarker screening of type 2 diabetes and type 2 diabetic coronary heart diseases

Type 2 diabetes mellitus (T2DM) and type 2 diabetic coronary heart diseases (T2DM–CHD) are directly associated with metabolism disorder of lipid. In the present study, GC–MS followed by multivariate statistical analysis has been successfully applied to plasma free fatty acid metabolic profiling in T2DM and T2DM–CHD. Because principal component analysis and partial least squares-linear discriminant analysis both failed to the class separation among T2DM, T2DM–CHD, and control, uncorrelated linear discriminant analysis (ULDA) was proposed and successfully discriminated these three groups. The predictive correct rates were 81.03%, 85.37%, 88.89% for control and T2DM, control and T2DM–CHD, T2DM and T2DM–CHD, respectively. Furthermore, three potential biomarkers were screened. ULDA are much more efficient than PCA and PLS for discrimination analysis of complex data set. It is undoubtedly that such newly multivariate analysis method will promote and widen the application of metabonome analysis in disease clinical diagnosis.     

Circulating RNAs as predictive markers for the progression of type 2 diabetes

Type 2 Diabetes Mellitus (T2DM) is the most prevalent form of diabetes in the USA, thus, the identification of biomarkers that could be used to predict the progression from prediabetes to T2DM would be greatly beneficial. Recently, circulating RNA including microRNAs (miRNAs) present in various body fluids have emerged as potential biomarkers for various health conditions, including T2DM. Whereas studies that examine the changes of miRNA spectra between healthy controls and T2DM individuals have been reported, the goal of this study is to conduct a baseline comparison of prediabetic individuals who either progress to T2DM, or remain prediabetic. Using an advanced small RNA sequencing library construction method that improves the detection of miRNA species, we identified 57 miRNAs that showed significant concentration differences between progressors (progress from prediabetes to T2DM) and non‐progressors. Among them, 26 have been previously reported to be associated with T2DM in either body fluids or tissue samples. Some of the miRNAs identified were also affected by obesity. Furthermore, we identified miRNA panels that are able to discriminate progressors from non‐progressors. These results suggest that upon further validation these miRNAs may be useful to predict the risk of conversion to T2DM from prediabetes.     

Scavenger receptor Class B type I as a potential risk stratification biomarker and therapeutic target in cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of mortality globally. There are few useful markers available for CVD risk stratification that has proven clinical utility. Scavenger receptor B type I (SR-BI) is a cell surface protein that plays a major role in cholesterol homeostasis through its interaction with high-density lipoprotein-cholesterol (HDL-C) esters (CE). HDL delivers CE to the liver through selective uptake by the SR-BI. SR-BI also regulates the inflammatory response. It has been shown that SR-BI overexpression has beneficial, protective effects in atherogenesis, and there is considerable interest in developing antiatherogenic strategies that involve SR-BI-mediated increases in reverse cholesterol transport through HDL and/or low-density lipoprotein. Further investigations are essential to explore the clinical utility of this approach. Moreover, there is growing evidence showing associations between genetic variants with modulation of SR-BI function that may, thereby, increase CVD risk. The aim of the current review was to provide an overview of the possible molecular mechanisms by which SR-BI may affect CVD risk, and the clinical implications of this, with particular emphasis on preclinical studies on genetic changes of SR-BI and CVD risk.     

Assessment of serum tenascin-C and growth differentiation factor-15 among type 2 diabetes mellitus patients with and without acute coronary syndrome

BackgroundHigh prevalence of type 2 diabetes mellitus (T2DM) is associated with a higher prevalence of acute coronary syndrome (ACS). Inflammation is one of the important contributors to the pathogenesis and complications of coronary atherosclerotic plaque. Growth Differentiation Factor-15 (GDF-15) and Tenascin-C (TNC) play an important role in the initiation of atherosclerotic plaque as well as its rupture. The aim of the study was to evaluate the association between serum GDF-15, TNC, and the risk of ACS among T2DM patients.MethodsAnthropometric parameters, routine biochemical investigations like liver and renal function tests, lipid profile, and Creatine Kinase-Total (CK-T), Creatine Kinase-MB (CK-MB) were measured in 42 T2DM patients with ACS and 42 T2DM patients. Serum GDF-15 and TNC were measured by Human Sandwich-ELISA kits.ResultsSerum GDF-15 and TNC levels were significantly higher in T2DM patients with ACS as compared to T2DM patients. Serum GDF-15 was significantly correlated with waist circumference, diastolic blood pressure, pulse, serum CK-T, and CK-MB. Serum TNC was significantly correlated with the pulse, serum CK-T, CK-MB, high-density lipoprotein-cholesterol, and blood urea nitro GEN. Multivariate linear regression analysis showed that waist circumference was independently positively associated with serum GDF-15.ConclusionsT2DM patients with higher serum GDF-15 and TNC levels were at higher risk of acute coronary syndrome independent of other cardiovascular risk factors.     

Research update on the association between SFRP5, an anti-inflammatory adipokine,with obesity,type 2 diabetes mellitus and coronary heart disease

Secreted frizzled-related protein 5 (SFRP5), an anti-inflammatory adipokine secreted by adipocytes, has been demonstrated to exert its anti-inflammatory effect via antagonizing the non-canonical wingless-type family member 5A (WNT5A) signalling pathways. The WNT5A protein, as a potent pro-inflammatory signalling molecule, is strongly involved in a variety of inflammatory disorders such as obesity, type 2 diabetes mellitus (T2DM) and atherosclerosis. In this review, we systematically outlined the current understanding on the roles of SFRP5 in the pathogenesis of three inflammatory diseases including obesity, T2DM and coronary heart disease (CHD). Our review might stimulate future research using SFRP5 as a promising novel therapeutic target for the treatment of obesity, T2DM and CHD.     

The potential of adipokines as biomarkers and therapeutic agents for vascular complications in type 2 diabetes mellitus

Over the past decades, there has been a major increase in type 2 diabetes (T2D) prevalence in most regions of the world. Diabetic patients are more prone to cardiovascular complications. Accumulating evidence suggests that adipose tissue is not simply an energy storage tissue but it also functions as a secretory tissue producing a variety of bioactive substances, also referred to as adipokines. The balance between pro-inflammatory adipokines and protective adipokines is disturbed in type 2 diabetes, this can be regarded as adipose tissue dysfunction which partly promote the pathogenesis of diabetes complications. In this review, we not only discuss the favorable adipokines like adiponectin, omentin, C1q tumor necrosis factor-related proteins, but also unfavorable ones like resisitin and visfatin, in the aim of finding potential biomarkers recommended for the clinical use in the diagnosis, prognosis and follow up of patients with T2D at high risk of developing cardiovascular diseases as well as leading to new therapeutic approaches.     

浅析肠道菌群与2型糖尿病及冠心病的关系

糖尿病和冠心病是当前危害公共健康的最普遍的问题,它们的发病率逐年升高。由糖尿病引发的心脑血管、肾、周围神经、眼、足等并发症增加了患者致残或致死的风险。冠心病的常见并发症如心肌梗塞、心源性休克和心力衰竭等,严重时也会危及患者生命。研究表明,肠道菌群紊乱可通过诱发炎症反应、胰岛素抵抗、脂质代谢异常、提高血尿酸水平等途径,增加2型糖尿病和冠心病的发病率,从而影响这些疾病的发展及预后,其诱发2型糖尿病的机制含内毒素机制、短链脂肪酸机制和胆汁酸机制等。本文从肠道菌群失调的角度综述肠道菌群与2型糖尿病及冠心病的关系。     

2型糖尿病与糖尿病肾病患者微炎症及肠道微生物多样性分析

目的 分析2型糖尿病(T2DM)及糖尿病肾病(DKD)患者微炎症情况和肠道微生物多样性。 方法 将2016年4月至2019年7月在我院进行治疗的68例T2DM患者(T2DM组)和57例DKD患者(DKD组)纳入研究,选择同期于我院进行健康体检的36例志愿者作为对照组。收集3组对象一般资料、血液标本和粪便标本,测定血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDLC)、高密度脂蛋白胆固醇(HDLC)、糖化血红蛋白(HbAlc)、空腹血糖(FBG)、超敏C反应蛋白(hsCRP)、白细胞介素6(IL6)水平,并对肠道细菌进行16S rDNA序列测序。比较3组对象一般资料,血液指标,肠道菌群门水平构成情况,肠道菌群多样性,肠道菌属差异性,并对患者炎性指标与菌群种类进行相关性分析。 结果 DKD组患者糖尿病病程长于T2DM组(P结论 2型糖尿病患者普遍存在微炎症和肠道菌群失衡,微炎症程度与肾脏病变和肠道菌群数量密切相关。T2DM与DKD患者在肠道菌群结构上具有一致性和差异性,肠道菌群检测有可能成为预测T2DM患者发生肾脏病变的风险指标。     

Diagnostic utility of BNP,corin and furin as biomarkers for cardiovascular complications in type 2 diabetes mellitus patients

Abstract

Context: The number of patients with type 2 diabetes mellitus (T2DM) is progressively increasing, and diabetic cardiovascular complications have become a public health problem. Brain or B-type natriuretic peptide (BNP) is a cardiac hormone synthesized as a pre-pro-peptide. pro-BNP is produced by cleaving the signal peptide then two proprotein convertases, corin and furin cleave pro-BNP to form a biologically active hormone. Two corin single nucleotide polymorphisms (SNPs) have been reported to alter corin protein conformation and impair its biological activity.

Objective: We aimed to investigate the potential role of corin and furin in comparison to BNP as biomarkers for predicting cardiovascular complications in T2DM patients. The association of corin gene SNPs with corin levels was also examined.

Methods: Seventy-five subjects were recruited in this study, including 25 T2DM patients with complications, 25 T2DM patients without complications as well as 25 healthy subjects. Plasma BNP, corin and furin levels were measured using enzyme-linked immunosorbent assays. Two corin SNPs were genotyped using allele specific oligonucleotide-polymerase chain reaction.

Results: Both furin and BNP were found to be more sensitive than corin (80% versus 56%, p?=?0.008), whereas furin showed higher specificity when compared to BNP (96% versus 84%, p?=?0.041) and corin (96% versus 64%, p?<?0.0001) in predicting cardiovascular complications in T2DM patients. Corin SNPs are not associated with corin levels, neither in the entire study cohort nor in the subgroup of T2DM patients with cardiovascular complications (p?>?0.05).

Conclusions: Furin may be useful, either alone or in combination with other biomarkers, for cardiovascular risk stratification assessment in T2DM patients.     

Landscape of the relationship between type 2 diabetes and coronary heart disease through an integrated gene network analysis

Type 2 diabetes (T2D) and coronary artery disease (CAD) are closely related chronic diseases with high prevalence and morbidity. However, a comprehensive comparison of the two diseases is lacking. Recent genome-wide association studies (GWAS) have identified a handful of single nucleotide polymorphisms (SNPs) that are significantly associated with the risk of T2D and CAD. These most significant findings may help interpret the pathogenesis of T2D and CAD. However, tremendous results from these GWAS are ignored. Here we revisited the raw datasets of these GWAS and performed an integrated gene network analysis to unveil the relationship between T2D and CAD by combining multiple datasets including protein–protein interaction (PPI) database, publication libraries, and pathway datasets. Our results showed that majority of genes were involved in the first module (1122 genes in T2D and 895 in CAD). Four pathways were found to be common in both T2D and CAD, including regulation of actin cytoskeleton, calcium signaling pathway, MAPK signaling pathway and focal adhesion (all P < 0.00001). MAX which was involved in small cell lung cancer pathway was a hub gene unique to T2D (OR = 1.2, P = 0.006) but not in CAD. In contrast, three hub genes including PLEKHG5 (T2D: OR = 1, P = 1; CAD: OR = 1.12, P = 0.006), TIAM1 (T2D: OR = 1, P = 1; CAD: OR = 1.48, P = 0.004) and AKAP13 (T2D: OR = 1, P = 1; CAD: OR = 1.38, P = 0.001) were hub genes unique to CAD. Moreover, for some hub genes (such as SMAD3) that were susceptible to both T2D and CAD, their associated polymorphisms were unique to each of the two diseases. Our findings might provide a landscape of the relationship between T2D and CAD.     

Homocysteine concentration and adenosine A2A receptor production by peripheral blood mononuclear cells in coronary artery disease patients

Hyperhomocysteinemia is associated with coronary artery disease (CAD). The mechanistic aspects of this relationship are unclear. In CAD patients, homocysteine (HCy) concentration correlates with plasma level of adenosine that controls the coronary circulation via the activation of adenosine A_2A receptors (A_2AR). We addressed in CAD patients the relationship between HCy and A_2AR production, and in cellulo the effect of HCy on A_2AR function. 46 patients with CAD and 20 control healthy subjects were included. We evaluated A_2AR production by peripheral blood mononuclear cells using Western blotting. We studied in cellulo (CEM human T cells) the effect of HCy on A_2A R production as well as on basal and stimulated cAMP production following A_2A R activation by an agonist‐like monoclonal antibody. HCy concentration was higher in CAD patients vs controls (median, range: 16.6 [7‐45] vs 8 [5‐12] µM, P < 0.001). A_2A R production was lower in patients vs controls (1.1[0.62‐1.6] vs 1.53[0.7‐1.9] arbitrary units, P < 0.001). We observed a negative correlation between HCy concentration and A_2A R production (r = ?0.43; P < 0.0001), with decreased A_2A R production above 25 µM HCy. In cellulo, HCy inhibited A_2AR production, as well as basal and stimulated cAMP production. In conclusion, HCy is negatively associated with A_2A R production in CAD patients, as well as with A_2A R and cAMP production in cellulo. The decrease in A_2A R production and function, which is known to hamper coronary blood flow and promote inflammation, may support CAD pathogenesis.     

Mortality and pre-hospitalization use of low-dose aspirin in COVID-19 patients with coronary artery disease

To determine whether pre-hospitalization use of aspirin is associated with all-cause mortality in coronavirus disease 2019 (COVID-19) patients with coronary artery disease (CAD). We recruited 183 adult patients with CAD diagnosed with COVID-19, including 52 taking low-dose aspirin (mean [SD] age, 69.7 [1.1] years; 59.6% men) and 131 without using aspirin (mean [SD] age, 71.8 [0.9] years; 51.9% men), who were admitted in the Tongji hospital in Wuhan, China from January 10, 2020 to March 30, 2020. There was no difference on in-hospital mortality between aspirin group and non-aspirin group (21.2% vs. 22.1%, P = .885). Similarly, for critically severe COVID-19 patients, the mortality in aspirin group was close to that in non-aspirin group (44% vs. 45.9%, P = .872). Moreover, the percentage of patients with CAD taking low-dose aspirin did not differ between those survivors and non-survivors (28.7% vs. 27.5%, P = .885). Meanwhile, the usage of aspirin was not correlated with all-cause mortality in multivariate analysis (OR = 0.944, 95% CI: 0.411-2.172, P = .893). Collectively, our study suggested that the pre-hospitalization use of low-dose aspirin was not associated with the clinical outcome of patients with CAD hospitalized with COVID-19 infections.