Plasma Proteomic Study in Pulmonary Arterial Hypertension Associated with Congenital Heart Diseases

The complement cascade in lung injury and disease

BACKGROUND

The complement system is an important arm of immune defense bringing innate and adaptive immunity. Although originally regarded as a major complementary defense mechanism against pathogens, continuously emerging evidence has uncovered a central role of this complex system in several diseases including lung pathologies.

MAIN BODY

Complement factors such as anaphylatoxins C3a and C5a, their receptors C3aR, C5aR and C5aR2 as well as complement inhibitory proteins CD55, CD46 and CD59 have been implicated in pathologies such as the acute respiratory distress syndrome, pneumonia, chronic obstructive pulmonary disease, asthma, interstitial lung diseases, and lung cancer. However, the exact mechanisms by which complement factors induce these diseases remain unclear. Several complement-targeting monoclonal antibodies are reported to treat lung diseases.

CONCLUSIONS

The complement system contributes to the progression of the acute and chronic lung diseases. Better understanding of the underlying mechanisms will provide groundwork to develop new strategy to target complement factors for treatment of lung diseases.

Proteome profiling of early gestational plasma reveals novel biomarkers of congenital heart disease

Prenatal diagnosis of congenital heart disease (CHD) relies primarily on fetal echocardiography conducted at mid-gestational age-the sensitivity of which varies among centers and practitioners. An objective method for early diagnosis is needed. Here, we conducted a case-control study recruiting 103 pregnant women with healthy offspring and 104 cases with CHD offspring, including VSD (42/104), ASD (20/104), and other CHD phenotypes. Plasma was collected during the first trimester and proteomic analysis was performed. Principal component analysis revealed considerable differences between the controls and the CHDs. Among the significantly altered proteins, 25 upregulated proteins in CHDs were enriched in amino acid metabolism, extracellular matrix receptor, and actin skeleton regulation, whereas 49 downregulated proteins were enriched in carbohydrate metabolism, cardiac muscle contraction, and cardiomyopathy. The machine learning model reached an area under the curve of 0.964 and was highly accurate in recognizing CHDs. This study provides a highly valuable proteomics resource to better recognize the cause of CHD and has developed a reliable objective method for the early recognition of CHD, facilitating early intervention and better prognosis.

Pulmonary arterial hypertension associated with congenital heart disease: An omics study

Pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD) is a severely progressive condition with uncertain physiological course. Hence, it has become increasingly relevant to clarify the specific mechanisms of molecular modification, which is crucial to identify more treatment strategies. With the rapid development of high-throughput sequencing, omics technology gives access to massive experimental data and advanced techniques for systems biology, permitting comprehensive assessment of disease occurrence and progression. In recent years, significant progress has been made in the study of PAH-CHD and omics. To provide a comprehensive description and promote further in-depth investigation of PAH-CHD, this review attempts to summarize the latest developments in genomics, transcriptomics, epigenomics, proteomics, metabolomics, and multi-omics integration.

Proteomic analysis of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare but fatal cardiovascular disorder with high morbidity and mortality. Diagnosis and treatment of this disease at an early stage would greatly improve outcomes. The molecular indicators of PAH are mostly nonspecific, and diagnostic and prognostic biomarkers are urgently needed. A more comprehensive understanding of the molecular mechanisms underlying this complex disease is crucial for the development of new and more effective therapeutics to improve patient outcomes. In this article, we review published literature on proteomic biomarkers and underlying molecular mechanisms in PAH and their value for disease management, aiming to deepen our understanding of the disease and, ultimately, pave the way for clinical application.

Proteomic profiling identifies key differences between inter-stage infants with single ventricle heart disease and healthy controls

Despite significant morbidity among infants with single ventricle heart disease (SVHD), clinical monitoring is limited by poor understanding of the underlying pathobiology. Proteomics can identify novel biomarkers and important pathways in complex disease. No prior study has evaluated whether the proteome of SVHD infants differs from healthy controls, how it shifts after stage 2 palliation, or whether differences can predict post-operative outcomes. We present a prospective cohort study of cardiovascular proteomic phenotyping in infants with SVHD undergoing stage 2 palliation. Twenty-nine pre-stage-2 SVHD infants and 25 healthy controls were enrolled. Outcomes included postoperative hypoxemia and endotracheal intubation time. Serum samples were drawn pre-operatively (systemic and pulmonary vein) and at 24 hours postoperation. Targeted cardiovascular proteomic analysis included 184 proteins. Partial least squares discriminant analysis distinguished cases from controls (Accuracy = 0.98, R² = 0.93, Q² = 0.81) with decreased inflammatory mediators and increased modulators of vascular tone. Partial least squares discriminant analysis also distinguished cases pre-operation vs. post-operation (Accuracy=0.98, R²=0.99, Q² = 0.92) with postoperative increase in both inflammatory and vascular tone mediators. Pre-operation pulmonary vein tissue inhibitor of metalloproteinase-1 (1.8x-fold, p=1.6 × 10^-4) and nidogen-1 (1.5x-fold, p=1.7 × 10^-4) were higher in subjects with longer endotracheal intubation time. Postoperation matrix metalloproteinase 7 levels were higher in subjects with greater postoperative hypoxemia (1.5x-fold, P= 1.97 × 10^-5). Proteomic analysis identifies significant changes among SVHD infants pre- and post-stage 2, and healthy controls. Tissue inhibitor of metalloproteinase-1, nidogen-1, and matrix metalloproteinase 7 levels are higher in SVHD cases with greater morbidity suggesting an important role for regulation of extracellular matrix production. Proteomic profiling may identify high-risk SVHD infants.

Biomarkers and key pathways in atrial fibrillation associated with mitral valve disease identified by multi-omics study

Background

Mitral valve disease (MVD)-associated atrial fibrillation (AF) is one of the most common arrhythmias with an increased risk of thromboembolic events. This study aimed to identify the molecular mechanisms and possible biomarkers for chronic AF in MVD by using multi-omics methods.

Methods

This prospective study enrolled patients with MVD (n=100) undergoing mitral valve replacement surgery. The patients were allocated into chronic AF and sinus rhythm (SR) groups. Plasma samples were collected preoperatively. Proteomics was performed with isobaric tags for relative and absolute quantitation (iTRAQ) to identify differential proteins (DPs) between the two groups. The selected DPs were then validated in a new cohort of patients by enzyme-linked immunosorbent assay (ELISA). A gas chromatography-mass spectrometer was used in the metabolomics study to identify differential metabolites (DMs). Bioinformatics analyses were performed to analyze the results.

Results

Among the 447 plasma proteins and 322 metabolites detected, 57 proteins and 55 metabolites, including apolipoprotein A-I (ApoA-I), apolipoprotein A-II (ApoA-II), LIM domain only protein 7 (LMO7), and vitronectin (VN) were differentially expressed between AF and SR patients. Bioinformatics analyses identified enriched pathways related to AF, including peroxisome proliferator-activated receptor alpha (PPARα), the renin angiotensin aldosterone system (RAAS), galactose, biosynthesis of unsaturated fatty acids, and linoleic acid metabolism.

Conclusions

Using integrated multi-omics technologies in MVD-associated AF patients, the present study, for the first time, revealed important signaling pathways, such as PPARα, as well as possible roles of other signaling pathways, including the RAAS and galactose metabolism to understand the molecular mechanism of MVD-associated AF. It also identified a large number of DPs and DMs. Some identified proteins and metabolites, such as ApoA-I, ApoA-II, LMO7, and VN, may be further developed as biomarkers for MVD-associated AF.

Integrative Omics to Characterize and Classify Pulmonary Vascular Disease

Advances in high-throughput biotechnologies have facilitated omics profiling, a key component of precision phenotyping, in patients with pulmonary vascular disease. Omics provides comprehensive information pertaining to genes, transcripts, proteins, and metabolites. The resulting omics big datasets may be integrated for more robust results and are amenable to analysis using machine learning or newer analytical methodologies, such as network analysis. Results from fully integrated multi-omics datasets combined with clinical data are poised to provide novel insight into pulmonary vascular disease as well as diagnose the presence of disease and prognosticate outcomes.

Serum biomarker analysis at the protein level on pulmonary hypertension secondary to old anterior myocardial infarction

Pulmonary hypertension (PH) related to old anterior myocardial infarction (OAMI) always accompanies a bad prognosis, and thus, we aimed to screen serum biomarkers related to PH in OAMI patients. According to right ventricular systolic pressure, we divided mice into sham, OAMI, and PH-OAMI groups and evaluated body, heart and lung weight, heart function, pulmonary blood flow velocity, cardiac fibrotic area, and pulmonary arteriole condition. Lung and serum were under the proteomic analysis. Levels of three identified proteins were measured. Compared with sham and OAMI mice, PH-OAMI mice showed heart dysfunction, low pulmonary blood flow, high right ventricular systolic pressure, heavy heart and lung weight, large cardiac fibrotic area, and pathological pulmonary arteriole remodeling (P<0.05 or P<0.01). Haptoglobin, annexin A5, and Ig mu chain C region of lung and serum were changed significantly in PH-OAMI mice (P<0.01). Then, we collected serum and clinical data, measured three serum protein levels, and performed multivariate regression and receiver operating characteristic curve in patients (normal, OAMI, and PH-OAMI groups). Compared with normal and OAMI patients, serum levels of three proteins in PH-OAMI patients were also altered notably (P<0.01). These three proteins can predict PH in OAMI patients (P<0.01). Receiver operating characteristic curve analysis revealed haptoglobin (cut-off value: 78.295, sensitivity: 62.8%, specificity: 94.4%), annexin A5 (cut-off value: 151.925, sensitivity: 41.9%, specificity: 82.4%), and Ig mu chain C region (cut-off value: 168.885, sensitivity: 86.0%, specificity: 79.6%) (P<0.01). Three circulating serum proteins can be useful for the categorization of OAMI patients with and without PH.

Protein biomarkers and risk scores in pulmonary arterial hypertension associated with ventricular septal defect: integration of multi-omics and validation

The molecular mechanisms underlying pulmonary arterial hypertension (PAH) in congenital ventricular septal defects (VSD) are unclear. We aimed to reveal molecular pathways and potential biomarkers by multi-omics analysis in VSD-PAH. Plasma from 160 children, including 120 VSD patients with/without PAH and 40 healthy children was studied by integrated proteomics, metabolomics, and bioinformatics analyses. Proteomics identified 107 differential proteins (DPs) between patients with/without PAH including significantly increased adiponectin (ADIPO), dopamine β-hydroxylase (DBH), alanyl membrane aminopeptidase (ANPEP), transferrin receptor 1, and glycoprotein Ib platelet α-subunit and decreased guanine nucleotide-binding protein Gs in VSD-PAH. Metabolomics discovered 191 differential metabolites between patients with/without PAH, including elevation of serotonin, taurine, creatine, sarcosine, and 2-oxobutanoate, and decrease of vanillylmandelic acid, 3,4-dihydroxymandelate, 15-keto-prostaglandin F_2α, fructose 6-phosphate, l-glutamine, dehydroascorbate, hydroxypyruvate, threonine, l-cystine, and 1-aminocyclopropane-1-carboxylate. The DPs were validated in a new cohort of patients (n = 80). Integrated analyses identified key pathways, including cAMP, ECM receptor interaction, AMPK, hypoxia-inducible factor 1, PI3K-Akt signaling pathways, and amino acid metabolisms. Increased plasma protein levels of DBH, ADIPO, and ANPEP were found to be independently associated with the occurrence of PAH, with a new total risk score from these three proteins developed for clinical diagnosis. In this integrated multi-omics analysis in VSD-PAH patients, we have, for the first time, found that VSD-PAH patients present important differential proteins, metabolites, and key pathways. We have developed a total risk score (based on the plasma concentration of DBH, ANPEP, and ADIPO) as a predictor of development of PAH in CHD-VSD patients. Therefore, these proteins may be used as biomarkers, and the new total risk score has significant clinical implications in the diagnosis of PAH.

Inflammation, immunity, and vascular remodeling in pulmonary hypertension; Evidence for complement involvement?

Pulmonary (arterial) hypertension (PH/PAH) is a life-threatening cardiopulmonary disorder. Experimental evidence suggests involvement of inflammatory and autoimmune processes in pathogenesis of PH/PAH, however the triggering and disease-promoting mechanisms remain unknown. The complement system is a key arm of innate immunity implicated in various pro-inflammatory and autoimmune diseases, yet, surprisingly little is known about the role of complement in PH/PAH pathogenesis. The preponderance of the existing data associates complement with PH/PAH via analysis of plasma and does not study the lung directly. Therefore, we aimed to resolve this by analyzing both the mechanisms of local lung-specific complement activation and the correlation of dysregulated plasma complement to clinical outcome in PAH patients. In our recent studies, reviewed herein, we show, for the first time, that  immunoglobulin-driven activation of the complement cascade, specifically its alternative pathway, in the pulmonary perivascular areas, is a key mechanism initiating pro-inflammatory processes in the early stage of experimental hypoxic PH (a form of "sterile inflammation"). In human patients with end-stage PAH, we have demonstrated that perivascular deposition of immunoglobulin G (IgG) and activation of the complement cascade are "longitudinally" persistent in the disease. We also showed, using unbiased network analysis, that plasma complement signaling, including again the Alternative pathway, is a prognostic factor of survival in patients with idiopathic PAH (IPAH). Based on these initial findings, we suggest that vascular-specific, immunoglobulin-driven dysregulated complement signaling triggers and maintains pulmonary vascular remodeling and PH. Future experiments in this area would facilitate discoveries on whether complement signaling can serve both as a biomarker and therapeutic target in PH/PAH.

Corrective surgery alters plasma protein profiling in congenital heart diseases and clinical perspectives

The final goal for treatment of congenital heart diseases (CHD) is to resume not only the normal heart structure but also physiology. The present study evaluates surgical results at molecular basis on the proteomic pattern in the pre- and post-operative period in tetralogy of Fallot (TOF) and ventricular septal defect (VSD) in order to find whether structure repair is associated with clinically important molecular changes in CHD. Differential protein analysis by using two-dimensional gel electrophoresis and mass spectrometry followed by ELISA validation was performed in the plasma samples of patients with TOF (n=82) or VSD (n=82) preoperatively, 6-month postoperatively, and in normal controls (n=82). A total of 473 protein spots in preoperative patients and 515 in postoperative patients were detected. Significantly (P<0.01) downregulated or upregulated proteins were detected. Validation of proteins in the new cohort of patients demonstrated that in VSD patients, postoperative complement component C3c (P<0.05) was partially and serum amyloid P-component (P<0.05) was completely recovered. In TOF patients, postoperative gelsolin (P<0.05) was partially recovered. In contrast, the elevated fibrinogen gamma chain level (P<0.01) in preoperative patients became normal postoperatively (P=0.1 vs. control). Thus, we have for the first time by using proteomic methods demonstrated that repair surgery for CHD not only corrects the structure malformation but also resumes the normality of certain altered proteins at molecular level. Identification of the recovered or unchanged proteins may facilitate the evaluation of the surgical results and the personalized management in postoperative period and long-term.

Screening and identification of serum biomarkers of osteoarticular tuberculosis based on mass spectrometry

BACKGROUND

In view of the current difficulty of clinically diagnosing osteoarticular tuberculosis, our aim was to use mass spectrometry to establish diagnostic models and to screen and identify serum proteins which could serve as potential diagnostic biomarkers for early detection of osteoarticular tuberculosis.

METHODS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to select an osteoarticular tuberculosis-specific serum peptide profile and establish diagnostic models. Further, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify potential serum biomarkers that could be used for auxiliary diagnosis of osteoarticular tuberculosis, and then clinical serum samples were used to verify these biomarkers by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We established four diagnostic models that can distinguish osteoarticular tuberculosis from rheumatoid arthritis, ankylosing spondylitis, osteoarticular infections, and healthy adults. The models were osteoarticular tuberculosis-rheumatoid arthritis, osteoarticular tuberculosis-ankylosing spondylitis, osteoarticular tuberculosis-osteoarticular infections, and osteoarticular tuberculosis-healthy adult, and their accuracy was 76.78%, 79.02%, 83.77%, and 88.16%, respectively. Next, we selected and identified 18 proteins, including complement factor H-related protein 1 (CFHR1) and complement factor H-related protein 2 (CFHR2), which were upregulated in the tuberculosis group only.

CONCLUSIONS

We successfully established four diagnostic models involving osteoarticular tuberculosis, rheumatoid arthritis, ankylosing spondylitis, osteoarticular infections, and healthy adults. Furthermore, we found that CFHR1 and CFHR2 may be two valuable auxiliary diagnostic indicators for osteoarticular tuberculosis. These results provide reference values for rapid and accurate diagnosis of osteoarticular tuberculosis.

Preoperative plasma biomarkers associated with atrial fibrillation after coronary artery bypass surgery

OBJECTIVES

Postoperative atrial fibrillation (POAF) is a common complication in coronary artery bypass grafting (CABG) procedures. This prospective study aimed to investigate predisposition of proteins and metabolites correlated to POAF after CABG and related cellular pathways.

METHODS

Preoperative plasma samples from patients undergoing CABG procedures were prospectively collected. After CABG, the patients were grouped to POAF or sinus rhythm (N = 170; n = 90 in the discovery set and n = 80 in the validation set). The plasma samples were analyzed using proteomics, metabolomics, and bioinformatics to identify the differential proteins and differential metabolites. The correlation between differential proteins and POAF was also investigated by multivariable regression analysis and receiver operator characteristic analysis.

RESULTS

In the POAF(+) group, 29 differential proteins and 61 differential metabolites were identified compared with the POAF(-) group. The analysis of integrated omics revealed that preoperative alteration of peroxisome proliferators-activated receptor α and glutathione metabolism pathways increased the susceptibility of POAF after CABG. There was a correlation between plasma levels of apolipoprotein-C3, phospholipid transfer protein, glutathione peroxidase 3, cholesteryl ester transfer protein, and POAF.

CONCLUSIONS

The present study for first time at multi-omics levels explored the mechanism of POAF and validated the results in a new cohort of patients, suggesting preexisting differential proteins and differential metabolites in the plasma of patients prone to POAF after CABG. Dysregulation of peroxisome proliferators-activated receptor α and glutathione metabolism pathways related to metabolic remodeling and redox imbalance-associated electrical remodeling may play a key role in the pathogenesis of POAF. Lower plasma phospholipid transfer protein, apolipoprotein-C3, higher cholesteryl ester transfer protein and glutathione peroxidase 3 levels are linked with POAF. These proteins/metabolites may be developed as biomarkers to predict POAF.

Immunoglobulin-driven Complement Activation Regulates Proinflammatory Remodeling in Pulmonary Hypertension

Rationale: Pulmonary hypertension (PH) is a life-threatening cardiopulmonary disorder in which inflammation and immunity have emerged as critical early pathogenic elements. Although proinflammatory processes in PH and pulmonary arterial hypertension (PAH) are the focus of extensive investigation, the initiating mechanisms remain elusive.Objectives: We tested whether activation of the complement cascade is critical in regulating proinflammatory and pro-proliferative processes in the initiation of experimental hypoxic PH and can serve as a prognostic biomarker of outcome in human PAH.Methods: We used immunostaining of lung tissues from experimental PH models and patients with PAH, analyses of genetic murine models lacking specific complement components or circulating immunoglobulins, cultured human pulmonary adventitial fibroblasts, and network medicine analysis of a biomarker risk panel from plasma of patients with PAH.Measurements and Main Results: Pulmonary perivascular-specific activation of the complement cascade was identified as a consistent critical determinant of PH and PAH in experimental animal models and humans. In experimental hypoxic PH, proinflammatory and pro-proliferative responses were dependent on complement (alternative pathway and component 5), and immunoglobulins, particularly IgG, were critical for activation of the complement cascade. We identified Csf2/GM-CSF as a primary complement-dependent inflammatory mediator. Furthermore, using network medicine analysis of a biomarker risk panel from plasma of patients with PAH, we demonstrated that complement signaling can serve as a prognostic factor for clinical outcome in PAH.Conclusions: This study establishes immunoglobulin-driven dysregulated complement activation as a critical pathobiological mechanism regulating proinflammatory and pro-proliferative processes in the initiation of experimental hypoxic PH and demonstrates complement signaling as a critical determinant of clinical outcome in PAH.

iTRAQ-based proteomics analysis reveals the deregulated proteins related to liver toxicity induced by melamine with or without cyanuric acid in mice

The administration of melamine alone or its combination with cyanuric acid was shown to have certain liver toxicity. However, the injury mechanism of melamine-related toxicity to liver remains poorly understood. In the present study, we investigated the deregulated proteins related to liver toxicity induced by melamine with or without cyanuric acid in mice using iTRAQ quantitative proteomics technique. A total of 166 proteins were significantly changed by the melamine treatment, of which, 36 proteins were up-regulated and 130 proteins were down-regulated. Whereas, 242 proteins were significantly changed by the combined treatment of melamine and cyanuric acid, of which 81 proteins were up-regulated and 161 proteins were down-regulated. The enriched analysis of GO terms and KEGG pathway on the altered proteins showed that both enriched main GO terms and KEGG pathways appear to be different between the two kinds of treatments: melamine and mixture of melamine and cyanuric acid. Based on western blotting technique, it was confirmed that the expression of three proteins: heat shock protein 70 (HSP70), protein disulphide isomerase 6 (PDIA6) and heat shock 70 kDa protein 4-like (HSPA4L) were agreement with the findings in iTRAQ-Based quantitative analysis. These identified proteins might participate in the regulation of a wide range of biological processes, such as immune and inflammatory function, unfolded proteins response in endoplasmic reticulum, DNA damage, and the apoptosis of liver cells. These results from this study provide a new way to gain insight into the mechanisms of melamine-related toxicity to liver in animals.

Plasma proteomics and the paediatric patient

INTRODUCTION

Plasma proteomics has been extensively utilized for studies that investigate various disease settings (e.g. cardiovascular disease), as well as to monitor the effect of pharmaceuticals on the plasma proteome (e.g. chemotherapy). However, plasma proteomic studies focusing on children represent a very small proportion of the plasma proteomic studies completed to date. Early disease detection and prevention is critical in pediatrics, as children must live with the disease outcomes for many years and often carry negative outcomes into adulthood. Pediatrics represents an area of plasma proteomics that is about to undergo a significant expansion. Areas covered: This review is based on a PubMed search focusing on five keywords that are plasma, biomarkers, pediatric, proteomics, and children. It is a comprehensive summary of plasma proteomic studies specific to the pediatric patient and discusses aspects such as the clinical setting, sample size, methodological approaches and outlines the significance of the findings. Expert commentary: Plasma proteomics is expanding significantly as a result of major advancements in proteomic technology. This is in synergy with the growing focus on true early disease detection and prevention in early life. We are about to see a new era of advanced medical science built from pediatric proteomics.

Altered plasma proteins released from platelets and endothelial cells are associated with human patent ductus arteriosus

Patent ductus arteriosus is the third most common congenital heart disease and resulted from the persistence of ductal patency after birth. Ductus arteriosus closure involves functional and structural remodeling, controlled by many factors. The changes in plasma protein levels associated with PDA closure are not known. Here we for the first time demonstrate six key differential plasma proteins in human patent ductus arteriosus patients using proteomic technology and present a model to illustrate the constriction and closure of ductus arteriosus. Differentially expressed proteins were analyzed by using isobaric tags for relative and absolute quantification and validated by enzyme-linked immunosorbent assay in new samples. The proteomic data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the data set identifier PXD008568. We found 74 upregulated and 98 downregulated proteins in the plasma of patients with PDA. Five decreased proteins (platelet factor 4, fibrinogen, von Willebrand factor, collagen, and mannose binding lectin-associated serine protease-2) and one increased protein (fibronectin) may increase the risk of patent ductus arteriosus. Those proteins are closely related to platelet activation and coagulation cascades, complement mannan-binding-lectin, and other systemic signaling pathways. Our findings for the first time indicate that the differential proteins involved in different pathways may play key roles in the nonclosure of the ductus arteriosus in humans and may be developed as biomarkers for diagnosis. All those findings may be served as the basis of understanding the etiology and pathogenesis of patent ductus arteriosus.

Increased circulating levels of tumor necrosis factor-like cytokine 1A and decoy receptor 3 correlate with SYNTAX score in patients undergoing coronary surgery

Objective

Chronic inflammation of the arteries is a critical mechanism responsible for coronary atherosclerosis. We aimed to determine if tumor necrosis factor (TNF)-like cytokine 1A (TL1A) and decoy receptor 3 (DcR3) were involved in promoting atherosclerosis.

Methods

We compared plasma levels of TL1A and DcR3 in patients with coronary artery disease (CAD) undergoing coronary artery bypass grafting (n=40) and patients without CAD group (n=37, normal coronary artery angiogram) by enzyme-linked immunosorbent assay. We also analyzed the correlation between CAD and SYNTAX scores.

Results

Plasma levels of TL1A and DcR3 were significantly higher in the CAD compared with the no-CAD group. Multivariate analysis showed that TL1A and DcR3 were significantly correlated with the presence of CAD, and receiver operating characteristic curve analysis indicated that both TL1A and DcR3 showed high sensitivity and specificity for diagnosing CAD. Furthermore, TL1A was positively and significantly correlated with SYNTAX score in CAD patients.

Conclusions

CAD patients requiring coronary artery bypass grafting have high circulating levels of both TL1A and DcR3, which may thus be useful biomarkers for diagnosing severe CAD. Furthermore, plasma levels of TL1A correlate with SYNTAX score, supporting its potential use as an indicator of the severity of CAD.

Analysis of the plasma proteome using iTRAQ and TMT-based Isobaric labeling

Over the past decade, chemical labeling with isobaric tandem mass tags, such as isobaric tags for relative and absolute quantification reagents (iTRAQ) and tandem mass tag (TMT) reagents, has been employed in a wide range of different clinically orientated serum and plasma proteomics studies. In this review the scope of these works is presented with attention to the areas of research, methods employed and performance limitations. These applications have covered a wide range of diseases, disorders and infections, and have implemented a variety of different preparative and mass spectrometric approaches. In contrast to earlier works, which struggled to quantify more than a few hundred proteins, increasingly these studies have provided deeper insight into the plasma proteome extending the numbers of quantified proteins to over a thousand.

Early Diagnostic Features of Left-to-Right Shunt-Induced Pulmonary Arterial Hypertension in Piglets

BACKGROUND

We aimed to establish early diagnostic characteristics of left-to-right shunt-induced pulmonary arterial hypertension (PAH) in a piglet model.

METHODS

A shunt-induced PAH in piglets (n = 9) was successfully established by anastomosis of vascular prosthesis from aorta to pulmonary artery with follow-up for 6 months by a number of diagnostic procedures.

RESULTS

PAH developed with mean pulmonary arterial pressure [PAP] of 30.2 ± 6.0 mm Hg immediately after operation and 33.5 ± 8.7 mm Hg at 3 months after operation with pulmonary vascular resistance increased to 4.0 ± 0.9 Wood units. There was a weak correlation on systolic PAP between catheterization and echocardiography but the Tei index was significantly correlated to systolic PAP. Magnetic resonance imaging demonstrated that the end-diastolic volume index, systolic volume index, ejection fraction of the ventricle, and ventricular mass index were sensitive indices. Technetium-99m single-photon emission computed tomography indicated increased blood flow in the upper and middle zones of both lungs. Positron emission tomography-computed tomography (PET-CT) demonstrated a higher kilo count (kct) of ¹⁸F-fluorodeoxyglucose in the right ventricular wall and both chambers at 3 months postoperatively (right ventricular wall: 5,708.3 ± 428.4 versus 3,965.5 ± 138.6 preoperatively, p = 0.003; both chambers: 2,963.6 ± 219.4 versus 1,710.1 ± 35.4 preoperatively, p < 0.05) as well as at 6 months for both chambers (p < 0.05).

CONCLUSIONS

In this successful left-to-right shunt-induced PAH model in piglets, sensitive indices including the Tei index, systolic volume index, ejection fraction, ventricular mass index, lung perfusion, and glycometabolism by PET-CT in early PAH are determined. For the first time, we report that glycometabolism by PET-CT is useful in early diagnosis. These indices may be used for the early diagnosis in the left-to-right shunt-induced PAH.

Chloride Channels are Involved in the Development of Atrial Fibrillation - A Transcriptomic and proteomic Study

Electrical and structural remodeling processes are contributors to the self-perpetuating nature of atrial fibrillation (AF). However, their correlation has not been clarified. In this study, human atrial tissues from the patients with rheumatic mitral valve disease in either sinus rhythm or persistent AF were analyzed using a combined transcriptomic and proteomic approach. An up-regulation in chloride intracellular channel (CLIC) 1, 4, 5 and a rise in type IV collagen were revealed. Combined with the results from immunohistochemistry and electron microscope analysis, the distribution of type IV collagen and effects of fibrosis on myocyte membrane indicated the possible interaction between CLIC and type IV collagen, confirmed by protein structure prediction and co-immunoprecipitation. These results indicate that CLICs play an important role in the development of atrial fibrillation and that CLICs and structural type IV collagen may interact on each other to promote the development of AF in rheumatic mitral valve disease.

Plasma protein profiling in patients undergoing coronary artery bypass grafting surgery and clinical significance

This study was designed to identify the protein profiling in patients with triple vessel coronary artery disease (CAD) undergoing CABG, in order to detect CAD-related differential proteins in these patients. CABG patients with triple vessel disease with/without left main stenosis (n =160) were compared to normal coronary angiographic subjects (n =160). Plasma samples of 20 males and 20 females in each group were analyzed with iTRAQ technique. ELISA test was used to test the chosen proteins from iTRAQ results in plasma samples from a new cohort of the CABG group (n=120, male/femal=61/59) and control (n =120, male/female=60/60). iTRAQ detected 544 proteins with 35 up-regulated and 41 down-regulated (change fold > 1.2 or < 0.83, p < 0.05). Three proteins including platelet factor 4 (PF4), coagulation factor XIII B chain (F13B), and secreted frizzled-related protein 1 (sFRP1) were selected for validation by using ELISA that demonstrated significant up-regulation of PF4 and sFRP1 (p < 0.05). There was a positive correlation between these proteins and CAD (p < 0.05) and myocardial infarction history (p < 0.05). Thus, we for the first time have found 76 proteins differentially expressed in plasma of CABG patients. The thrombotic disease/inflammation progress-related protein PF4 and sFRP1, a member of the Wnt/fz signal-transduction pathway and related to myocardial repair, are significantly up-regulated in triple-vessel disease with/without left main stenosis. PF4 may be developed as a biomarker for the diagnosis of the severity of CAD requiring CABG procedure.

Metaproteomic strategies and applications for gut microbial research

The human intestine hosts various complex microbial communities that are closely associated with multiple health and disease processes. Determining the composition and function of these microbial communities is critical to unveil disease mechanisms and promote human health. Recently, meta-omic strategies have been developed that use high-throughput techniques to provide a wealth of information, thus accelerating the study of gut microbes. Metaproteomics is a newly emerged analytical approach that aims to identify proteins on a large scale in complex environmental microbial communities (e.g., the gut microbiota). This review introduces the recent analytical strategies and applications of metaproteomics, with a focus on advances in gut microbiota research, including a discussion of the limitations and challenges of these approaches.

Remote Sensing between Liver and Intestine: Importance of Microbial Metabolites

Recent technological advancements including metagenomics sequencing and metabolomics have allowed the discovery of critical functions of gut microbiota in obesity, malnutrition, neurological disorders, asthma, and xenobiotic metabolism. Classification of the human gut microbiome into distinct "enterotypes" has been proposed to serve as a new paradigm for understanding the interplay between microbial variation and human disease phenotypes, as many organs are affected by gut microbiota modifications during the pathogenesis of diseases. Gut microbiota remotely interacts with liver and other metabolic organs of the host through various microbial metabolites that are absorbed into the systemic circulation.

PURPOSE OF REVIEW

The present review summarizes recent literature regarding the importance of gut microbiota in modulating the physiological and pathological responses of various host organs, and describes the functions of the known microbial metabolites that are involved in this remote sensing process, with a primary focus on the gut microbiota-liver axis.

RECENT FINDINGS

Under physiological conditions, gut microbiota modulates the hepatic transcriptome, proteome, and metabolome, most notably down-regulating cytochrome P450 3a mediated xenobiotic metabolism. Gut microbiome also modulates the rhythmicity in liver gene expression, likely through microbial metabolites, such as butyrate and propionate that serve as epigenetic modifiers. Additionally, the production of host hormones such as primary bile acids and glucagon like peptide 1 is altered by gut microbiota to modify intermediary metabolism of the host.

SUMMARY

Dysregulation of gut microbiota is implicated in various liver diseases such as alcoholic liver disease, non-alcoholic steatohepatitis, liver cirrhosis, cholangitis, and liver cancer. Gut microbiota modifiers such as probiotics and prebiotics are increasingly recognized as novel therapeutic modalities for liver and other types of human diseases.