Relationship between serum amino-terminal propeptide of type III procollagen and changes of left ventricular function after acute myocardial infarction

Inflammation and Fibrosis in Sleep-Disordered Breathing after Acute Myocardial Infarction

BACKGROUND

After acute myocardial infarction (AMI), inflammatory processes promote tissue remodeling at the infarct site. Procollagen III amino-terminal propeptide (PIIINP) is a circulating biomarker of type III collagen synthesis that has been shown to be associated with changes in left ventricular ejection fraction (LVEF) and predicts the occurrence of heart failure after AMI. We hypothesize that sleep-disordered breathing (SDB) promotes inflammation and myocardial fibrosis, leading to reduced myocardial salvage. Therefore, in patients with first-time AMI successfully treated with percutaneous coronary intervention (PCI), we aimed to investigate whether circulating levels of high-sensitivity C-reactive protein (hs-CRP) and PIIINP are elevated in patients with SDB compared to patients without SDB.

METHODS AND RESULTS

This cross-sectional analysis included a total of 88 eligible patients with first AMI and PCI pooled from two prospective studies and stratified according to the apnea-hypopnea index (AHI, with SDB: AHI ≥ 15 h-1). We analyzed circulating levels of hs-CRP and PIIINP 3-5 days after PCI. Patients with SDB had significantly higher levels of hs-CRP (18.3 mg/L [95% CI, 8.0-42.6] vs. 5.8 mg/L [95% CI, 4.2-19.8], p = 0.002) and PIIINP (0.49 U/mL [95% CI, 0.40-0.60] vs. 0.33 U/mL [95% CI, 0.28-0.43], p < 0.001). In a multivariable linear regression model accounting for important clinical confounders, SDB significantly predicted circulating levels of hs-CRP (p = 0.028). Similarly, only SDB was independently associated with PIIINP (p < 0.001). Only obstructive but not central AHI correlated with circulating levels of hs-CRP (p = 0.012) and PIIINP (p = 0.006) levels.

CONCLUSIONS

The presence of obstructive SDB after AMI was independently associated with increased circulating levels of hs-CRP and PIIINP. Our results emphasize the important role of SDB as a common comorbidity and indicate increased inflammation and myocardial fibrosis in these patients.

Extracellular Matrix in Heart Disease: Focus on Circulating Collagen Type I and III Derived Peptides as Biomarkers of Myocardial Fibrosis and Their Potential in the Prognosis of Heart Failure: A Concise Review

Accumulating evidence indicates that two major proteins are responsible for the structural coherence of bounding cardiomyocytes. These biomolecules are known as myocardial fibrillar collagen type I (COL1) and type III (COL3). In addition, fibronectin, laminin, fibrillin, elastin, glycoproteins, and proteoglycans take part in the formation of cardiac extracellular matrix (ECM). In physiological conditions, collagen synthesis and degradation in human cardiac ECM are well-regulated processes, but they can be impaired in certain cardiovascular diseases, such as heart failure (HF). Myocardial remodeling is part of the central mechanism of HF and involves cardiomyocyte injury and cardiac fibrosis due to increased fibrillar collagen accumulation. COL1 and COL3 are predominantly involved in this process. Specific products identified as collagen-derived peptides are released in the circulation as a result of abnormal COL1 and COL3 turnover and myocardial remodeling in HF and can be detected in patients' sera. The role of these products in the pathogenesis of cardiac fibrosis and the possible clinical implications are the focus of numerous investigations. This paper reviews recent studies on COL1- and COL3-derived peptides in patients with HF. Their potential application as indicators of myocardial fibrosis and prognostic markers of HF is also highlighted.

Circulating Aminoterminal Propeptide of Type III Procollagen as a Biomarker of Cardiovascular Events in Patients Undergoing Hemodialysis

AIM

Type Ⅲ collagen abundantly exists in the cardiovascular system, including the aorta and heart. We prospectively investigated whether serum levels of aminoterminal propeptide of type Ⅲ procollagen (PⅢNP), a circulating biomarker of cardiovascular fibrosis, could predict cardiovascular events in patients undergoing hemodialysis.

METHODS

Serum PⅢNP concentrations were measured in 244 patients undergoing maintenance hemodialysis (men, 126; women, 118; mean age, 64±11 years; dialysis duration, 11.5±7.8 years) by immunoradiometric assay in February 2005. The endpoint was cardiovascular events, and the patients were followed up until the endpoint was reached, or until January 31, 2011.

RESULTS

During the follow-up for 4.7±1.8 years, cardiovascular events occurred in 78 (30.3%) of 244 patients. Stepwise Cox hazard analysis revealed that cardiovascular events were associated with increased serum PⅢNP concentration (1 U/mL; hazard ratio, 1.616; P=0.0001). The median serum PⅢNP concentrations were higher in patients with cardiovascular events than in those without (2.30±0.19 U/mL vs 1.30±0.03 U/mL; P＜0.0001). When the patients were assigned to subgroups based on serum PⅢNP cut-off value for cardiovascular events of 1.75 U/mL, defined by receiver operating characteristic analysis, cardiovascular event-free survival rates at 5 years were lower (P=0.0001) in the subgroup of serum PⅢNP ≥1.75 U/mL than in that of serum PⅢNP ＜1.75 U/mL (31.9% vs 88.2%).

CONCLUSIONS

Serum PⅢNP could be a new biomarker for predicting the cardiovascular events in patients undergoing hemodialysis.

Cathepsin K-deficiency impairs mouse cardiac function after myocardial infarction

BACKGROUND

Extracellular matrix metabolism and cardiac cell death participate centrally in myocardial infarction (MI). This study tested the roles of collagenolytic cathepsin K (CatK) in post-MI left ventricular remodeling.

METHODS AND RESULTS

Patients with acute MI had higher plasma CatK levels (20.49 ± 7.07 pmol/L, n = 26) than those in subjects with stable angina pectoris (8.34 ± 1.66 pmol/L, n = 28, P = .01) or those without coronary heart disease (6.63 ± 0.84 pmol/L, n = 93, P = .01). CatK protein expression increases in mouse hearts at 7 and 28 days post-MI. Immunofluorescent staining localized CatK expression in cardiomyocytes, endothelial cells, fibroblasts, macrophages, and CD4⁺ T cells in infarcted mouse hearts at 7 days post-MI. To probe the direct participation of CatK in MI, we produced experimental MI in CatK-deficient mice (Ctsk^-/-) and their wild-type (Ctsk^+/+) littermates. CatK-deficiency yielded worsened cardiac function at 7 and 28 days post-MI, compared to Ctsk^+/+ littermates (fractional shortening percentage: 5.01 ± 0.68 vs. 8.62 ± 1.04, P < .01, 7 days post-MI; 4.32 ± 0.52 vs. 7.60 ± 0.82, P < .01, 28 days post-MI). At 7 days post-MI, hearts from Ctsk^-/- mice contained less CatK-specific type-I collagen fragments (10.37 ± 1.91 vs. 4.60 ± 0.49 ng/mg tissue extract, P = .003) and more fibrosis (1.67 ± 0.93 vs. 0.69 ± 0.20 type-III collagen positive area percentage, P = .01; 14.25 ± 4.12 vs. 6.59 ± 0.79 α-smooth muscle actin-positive area percentage, P = .016; and 0.82 ± 0.06 vs. 0.31 ± 0.08 CD90-positive area percentage, P = .008) than those of Ctsk^+/+ mice. Immunostaining demonstrated that CatK-deficiency yielded elevated cardiac cell death but reduced cardiac cell proliferation. In vitro studies supported a role of CatK in cardiomyocyte survival.

CONCLUSION

Plasma CatK levels are increased in MI patients. Heart CatK expression is also elevated post-MI, but CatK-deficiency impairs post-MI cardiac function in mice by increasing myocardial fibrosis and cardiomyocyte death.

Circulating markers of collagen types I, III, and IV in patients with dilated cardiomyopathy: relationships with myocardial collagen expression

Aims

Collagen‐derived peptides such as collagen I C‐terminal telopeptide (CITP) and procollagen III N‐terminal propeptide (PIIINP) have been conventionally used as markers of cardiac fibrosis. Collagen IV 7S domain (P4NP 7S) has been recently reported to be correlated with haemodynamics in patients with acute heart failure. We investigated whether these markers reflect cardiac remodelling and myocardial collagen expression.

Methods and results

In 80 patients with dilated cardiomyopathy, relationships of CITP, PIIINP, and P4NP 7S to clinical and echocardiographic variables were analysed. CITP and PIIINP were inversely correlated with estimated glomerular filtration rate (r = −0.41, P < 0.001 and r = −0.32, P = 0.004, respectively); P4NP 7S was positively correlated with B‐type natriuretic peptide (r = 0.32, P = 0.003) and γ‐glutamyltransferase (r = 0.38, P < 0.001). These correlations were significant even after adjustment by potential confounders, whereas all three collagen markers were not independently correlated with ejection fraction nor with left ventricular (LV) diastolic diameter. In 33 patients undergoing endomyocardial biopsy, myocardial collagen I and III mRNA expressions were correlated with LV end‐diastolic volume index (r = 0.42, P = 0.02 and r = 0.54, P = 0.002, respectively), whereas myocardial collagen IV mRNA expression was not correlated with LV end‐diastolic volume index nor with ejection fraction. Each collagen‐derived peptide was not significantly correlated with the myocardial expression of their corresponding collagen mRNA.

Conclusions

Our study shows that CITP, PIIINP, and P4NP 7S do not reflect myocardial collagen mRNA expression but presumably reflect extra‐cardiac organ injury in heart failure.

Preferential myofibroblast differentiation of cardiac mesenchymal progenitor cells in the presence of atrial fibrillation

Atrial fibrillation (AF) is characterized by electrical, contractile, and structural remodeling mediated by interstitial fibrosis. It has been shown that human cardiac mesenchymal progenitor cells (CMPCs) can be differentiated into endothelial, smooth muscle, and fibroblast cells. Here, we have investigated, for the first time, the contribution of CMPCs in the fibrotic process occurring in AF. As expected, right auricolae samples displayed significantly higher fibrosis in AF vs control (CTR) patients. In tissue samples of AF patients only, double staining for c-kit and the myofibroblast marker α-smooth muscle actin (α-SMA) was detected. The number of c-kit-positive CMPC was higher in atrial subepicardial regions of CTR than AF cells. AF-derived CMPC (AF-CMPC) and CTR-derived CMPC (Ctr-CMPC) were phenotypically similar, except for CD90 and c-kit, which were significantly more present in AF and CTR cells, respectively. Moreover, AF showed a lower rate of population doubling and fold enrichment vs Ctr-CMPC. When exogenously challenged with the profibrotic transforming growth factor-β1 (TGF-β1), AF-CMPC showed a significantly higher nuclear translocation of SMAD2 than Ctr-CMPC. In addition, TGF-β1 treatment induced the upregulation of COL1A1 and COL1A2 in AF-CMPC only. Further, both a marked production of soluble collagen and α-SMA upregulation have been observed in AF-CMPC only. Finally, electrophysiological studies showed that the inwardly rectifying potassium current (I_K1) was evenly present in AF- and Ctr-CMPC in basal conditions and similarly disappeared after TGF-β1 exposure. All together, these data suggest that AF steers the resident atrial CMPC compartment toward an electrically inert profibrotic phenotype.

Peri-interventional endothelin-A receptor blockade improves long-term outcome in patients with ST-elevation acute myocardial infarction

Endothelin (ET)-1 is a pro-fibrotic vasoconstrictive peptide causing microvascular dysfunction and cardiac remodelling after acute ST-elevation myocardial infarction (STEMI). It acts via two distinct receptors, ET-A and ET-B, and is involved in inflammation and atherogenesis. Patients with posterior-wall STEMI were randomly assigned to intravenous BQ-123 at 400 nmol/minute (min) or placebo over 60 min, starting immediately prior to primary percutaneous coronary intervention (n=54). Peripheral blood samples were drawn at baseline as well as after 24 hours and 30 days. Myeloperoxidase (MPO), as a marker of neutrophil activation and matrix metalloproteinase 9 (MMP-9), a marker of extracellular matrix degradation were measured in plasma. Clinical follow-up was conducted by an investigator blinded to treatment allocation over three years. During the median follow-up period of 3.6 years (interquartile range [IQR] 3.3–4.1) we observed a longer event-free survival in patients randomised to receive BQ-123 compared with patients randomised to placebo (mean 4.5 years (95% confidence interval: 3.9–5) versus mean 3 years (2.2–3.7), p=0.031). Patients randomised to ET-A receptor blockade demonstrated a greater reduction of MPO levels from baseline to 24 hours compared to placebo-treated patients (-177 ng/ml (IQR 103–274) vs –108 ng/ml (74–147), p=0.006). In addition, a pronounced drop in MMP-9 levels (-568 ng/ml (44–1157) vs –117 ng/ml (57–561), p=0.018) was observed. There was no significant difference in amino-terminal propetide of pro-collagen type III levels. In conclusion, short-term administration of BQ-123 leads to a reduction in MPO, as well as MMP-9 plasma levels and to a longer event-free survival in patients with STEMI.

ClinicalTrials.gov Identifier: NCT00502528

Relationship of biomarkers of extracellular matrix with myocardial function in Type 2 diabetes mellitus

AIM

The study evaluated the relationship of extracellular matrix and renin angiotensin system with myocardial dysfunction in Type 2 diabetes mellitus.

METHODS

All patients underwent resting and exercise echocardiography, including conventional parameters, E/E' ratio, global longitudinal strain and diastolic function reserve index. Plasma matrix metalloproteinase-1, TIMP-1, amino-terminal propeptide of type I and type III procollagen and renin angiotensin system activity were measured.

RESULTS

As patients with diastolic dysfunction had a higher plasma level of TIMP-1 and propeptide of type III procollagen than those with no diastolic dysfunction. After multivariate adjustment, TIMP-1 associated with E/E' (both at rest and stress) and diastolic function reserve index.

CONCLUSION

TIMP-1 is independently associated with myocardial diastolic dysfunction in patients with Type 2 diabetes mellitus.

Vascular proteomics in metabolic and cardiovascular diseases

The vasculature is essential for proper organ function. Many pathologies are directly and indirectly related to vascular dysfunction, which causes significant morbidity and mortality. A common pathophysiological feature of diseased vessels is extracellular matrix (ECM) remodelling. Analysing the protein composition of the ECM by conventional antibody-based techniques is challenging; alternative splicing or post-translational modifications, such as glycosylation, can mask epitopes required for antibody recognition. By contrast, proteomic analysis by mass spectrometry enables the study of proteins without the constraints of antibodies. Recent advances in proteomic techniques make it feasible to characterize the composition of the vascular ECM and its remodelling in disease. These developments may lead to the discovery of novel prognostic and diagnostic markers. Thus, proteomics holds potential for identifying ECM signatures to monitor vascular disease processes. Furthermore, a better understanding of the ECM remodelling processes in the vasculature might make ECM-associated proteins more attractive targets for drug discovery efforts. In this review, we will summarize the role of the ECM in the vasculature. Then, we will describe the challenges associated with studying the intricate network of ECM proteins and the current proteomic strategies to analyse the vascular ECM in metabolic and cardiovascular diseases.

Prognostic value of collagen turnover biomarkers in cardiac resynchronization therapy: A subanalysis of the TRUST CRT randomized trial population

BACKGROUND

A substantial proportion of patients do not respond to cardiac resynchronization therapy (CRT). Various echocardiographic and biochemical markers including collagen turnover biomarkers were suggested to predict CRT results. However, pathological significance of collagen turnover biomarkers in CRT remains controversial.

OBJECTIVE

The aim of the present study was to evaluate the relationship between levels of collagen turnover biomarkers (amino-terminal propeptide of procollagen type I and amino-terminal propeptide of procollagen type III [PIIINP]), N-terminal of the prohormone brain natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein, and matrix metalloproteinases (metalloproteinase-2 and metalloproteinase-9) and echocardiographic response to CRT and clinical outcomes.

METHODS

The study population consisted of patients enrolled in the Triple Site Versus Standard Cardiac Resynchronization Therapy trial. Blood samples were obtained before implantation of a CRT with defibrillator. The levels of PIIINP, amino-terminal propeptide of procollagen type I, metalloproteinase-2, and metalloproteinase-9 were determined using commercially available ELISA kits. High-sensitivity C-reactive protein and NT-proBNP levels were determined in a standard way.

RESULTS

Samples were collected from 74 of 100 enrolled patients. The multivariate logistic regression analysis demonstrated that low PIIINP levels (odds ratio [OR] 3.56; 95% confidence interval [CI] 1.23-10.24; P = .017) and baseline ejection fraction (OR 2.14; 95% CI 1.11-4.11; P = .02) were favorably associated with echocardiographic response. PIIINP and NT-proBNP levels appeared to be independent predictors of all-cause mortality (PIIINP: OR 3.11; 95% CI 1.21-7.89; P = .033; NT-proBNP: OR 2.05; 95% CI 1.11-4.96; P = .039) and risk of major cardiac adverse event (PIIINP: OR 3.56; 95% CI 1.53-9.15; P = .007; NT-proBNP: OR 4.51; 95% CI 1.75-11.6; P = .001). PIIINP levels showed significant additive value in predicting mortality as compared with NT-proBNP levels, but they were not superior to ejection fraction in predicting response. Survival analysis with cutoff values identified by receiver operating characteristic analysis confirmed a significant benefit associated with low baseline PIIINP levels.

CONCLUSION

Low PIIINP levels are associated with favorable echocardiographic response and long-term survival in CRT recipients.

Influence of Renal Sympathetic Denervation on Cardiac Extracellular Matrix Turnover and Cardiac Fibrosis

BACKGROUND

Renal sympathetic denervation (RSD) represents an effective treatment option for patients with resistant arterial hypertension (HT). Extracellular matrix (ECM) turnover and deposition are essential processes in HT-related cardiovascular remodeling, fibrosis, and cardiac hypertrophy and contribute to hypertensive heart disease.

OBJECTIVES

The primary aim of the present study was to examine the effect of RSD on increased collagen turnover as reflected by serum levels of amino-terminal pro-peptides (PINP, PIIINP) and a carboxyl-terminal pro-peptide (PICP), specific biomarkers for cardiac ECM turnover and cardiovascular fibrosis.

METHODS

A total of 100 consecutive patients (mean age: 65.9±10.1 years) undergoing RSD were included in this study. A therapeutic response was defined as an office systolic blood pressure (SBP) reduction of >10mm Hg 6 months after RSD. Venous serum samples for measurement of PICP, PINP, and PIIINP were collected prior to and 6 months after RSD.

RESULTS

A significant reduction in the office SBP of 24.3 mm Hg (SBP baseline: 166.9±14.3 mm Hg (P < 0.001) was documented 6 months after RSD. At this time point, the serum levels of PICP, PINP, and PIIINP (P < 0.01) were significantly decreased compared to baseline values in patients with an increased collagen turnover, showing significant differences comparing BP responders and nonresponders.

CONCLUSION

In addition to the effective blood pressure reduction in response to RSD, this study demonstrates a positive effect of RSD on biomarkers reflecting cardiovascular ECM turnover and deposition. These results suggest a beneficial effect of RSD on cardiovascular fibrosis, hypertensive heart disease, and end-organ damage in high-risk patients.

Procollagen type III amino-terminal propeptide: a serum biomarker of left ventricular remodelling in paediatric dilated cardiomyopathy

BACKGROUND

Procollagen type III amino-terminal propeptide is a collagen III cleavage product released in blood. The serum levels of this propeptide in adults with dilated cardiomyopathy are associated with cardiac remodelling and prognosis. The utility of procollagen type III amino-terminal propeptide as a biomarker in paediatric dilated cardiomyopathy is unknown.

METHODS

This was a prospective, longitudinal study of children with dilated cardiomyopathy and changes in procollagen type III amino-terminal propeptide. The serum level of propeptide was measured serially, compared with paediatric normal values, and correlated with clinical status and left ventricular size and function on echocardiograms and cardiac magnetic resonance imaging.

RESULTS

Procollagen type III amino-terminal propeptide was measured serially in 149 samples from 39 patients, age 9.0±6.4 years, followed up for 16.8±16.3 months. Procollagen type III amino-terminal propeptide in dilated cardiomyopathy was higher than in normal children. On multivariate analyses, procollagen type III amino-terminal propeptide had a positive correlation with left ventricular dilation, left ventricular end-diastolic diameter index (p<0.0001), and left ventricular end-diastolic diameter Z-score (p=0.0003), and a negative correlation with shortening fraction changes over time (p=0.001). Patients with myocarditis (n=12) had higher procollagen type III amino-terminal propeptide values than those with idiopathic dilated cardiomyopathy (n=20).

CONCLUSIONS

Procollagen type III amino-terminal propeptide increases with left ventricular dilation and decreases with improvement in systolic function in paediatric dilated cardiomyopathy, indicating a role as a biomarker of cardiac remodelling in children. The diagnostic utility of procollagen type III amino-terminal propeptide to differentiate myocarditis from idiopathic dilated cardiomyopathy warrants further investigation.

The N-terminal propeptide of type III procollagen in patients with acute coronary syndrome: a link between left ventricular end-diastolic pressure and cardiovascular events

Background

Despite the usefulness of N-terminal propeptide of type III procollagen (PIIINP) in detecting enhanced collagen turnover in patients with congestive heart failure, the value added by PIIINP to the use of clinical variables and echocardiography in relation to directly measured left ventricular (LV) end-diastolic pressure (EDP) and the outcome of acute coronary syndrome (ACS) has not been clearly defined.

Methods and Results

This study involved 168 adult patients with ACS, who underwent echocardiography, measurement of serum PIIINP levels, and cardiac catheterization. Pulsed wave tissue Doppler imaging (PWTDI), which revealed mean peak systolic (s′), early (e′), and late diastolic (a′) velocities, was carried out and the eas index of LV function was evaluated: e′/(a′×s′). The patients were divided into three study groups based on the degree of LVEDP – normal (<16 mmHg), intermediate (16–30 mmHg), and high (>30 mmHg) LVEDP. All patients were followed-up to determine cardiac-related death and revascularization. Patients with high LVEDP had significantly more PIIINP than those with intermediate or normal LVEDP (all post hoc p<0.05). The presence of coronary artery disease, the left atrial volume index (LAVI), the ratio of transmitral early and late diastolic flow velocities, a′, and the eas index were significantly correlated with LVEDP. According to multiple stepwise analysis, PIIINP, LAVI and the eas index were the three independent predictors of the level of LVEDP (PIIINP, p <0.001; LAVI, p = 0.007; eas index, p = 0.021). During follow-up (median, 24 months), 32 participants suffered from cardiac events, PIIINP and LAVI were significant predictors of cardiac mortality and hospitalization (PIIINP, hazard ratio (HR) 2.589, p = 0.002; LAVI, HR 1.040, p = 0.027).

Conclusions

PIIINP is a highly effective means to evaluate LVEDP in patients with ACS. The PIIINP is also correlated with cardiac mortality and revascularization, providing an additional means of evaluating and managing patients with ACS.

Cardiac biomarkers in heart failure

BACKGROUND

Heart failure is a syndrome characterized by the inability of the heart to meet the body's circulatory demands. Heart failure is a growing health issue worldwide and the prevalence of heart failure is expected to rise as populations age. Therapies and interventions for a variety of cardiac conditions continue to advance and biomarkers will play an increasing role in patient management.

METHODS

This is a review of the clinical research in blood based biomarkers for diagnosis, prognosis and therapeutic guidance of heart failure. The focus of this review is biomarkers that are currently available for clinical measurement, and their current and potential for applications for managing heart failure patients.

RESULTS

The various biologic pathways and physiologic processes of heart failure biomarkers represent a host of different including inflammation, remodeling, strain, neurohormonal activation, metabolism and cardiac myocyte injury. The clinical characteristics and applications of each heart failure biomarker are discussed.

CONCLUSION

As populations age and effective treatments and interventions for coronary artery disease improve, heart failure will increase in incidence and prevalence. Blood biomarkers will play an increasing role in the early diagnosis, therapeutic monitoring and management of heart failure patients in the future.

Tissue inhibitor of metalloproteinases (TIMPs) in heart failure

Remodeling of the myocardium and the extracellular matrix (ECM) occurs in heart failure irrespective of its initial cause. The ECM serves as a scaffold to provide structural support as well as housing a number of cytokines and growth factors. Hence, disruption of the ECM will result in structural instability as well as activation of a number of signaling pathways that could lead to fibrosis, hypertrophy, and apoptosis. The ECM is a dynamic entity that undergoes constant turnover, and the integrity of its network structure is maintained by a balance in the function of matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitor of metalloproteinases (TIMPs). In heart disease, levels of MMPs and TIMPs are altered resulting in an imbalance between these two families of proteins. In this review, we will discuss the structure, function, and regulation of TIMPs, their MMP-independent functions, and their role in heart failure. We will review the knowledge that we have gained from clinical studies and animal models on the contribution of TIMPs in the development and progression of heart disease. We will further discuss how ECM molecules and regulatory genes can be used as biomarkers of disease in heart failure patients.

Cardiac fibroblasts, fibrosis and extracellular matrix remodeling in heart disease

Fibroblasts comprise the largest cell population in the myocardium. In heart disease, the number of fibroblasts is increased either by replication of the resident myocardial fibroblasts, migration and transformation of circulating bone marrow cells, or by transformation of endothelial/epithelial cells into fibroblasts and myofibroblasts. The primary function of fibroblasts is to produce structural proteins that comprise the extracellular matrix (ECM). This can be a constructive process; however, hyperactivity of cardiac fibroblasts can result in excess production and deposition of ECM proteins in the myocardium, known as fibrosis, with adverse effects on cardiac structure and function. In addition to being the primary source of ECM proteins, fibroblasts produce a number of cytokines, peptides, and enzymes among which matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs), directly impact the ECM turnover and homeostasis. Function of fibroblasts can also in turn be regulated by MMPs and TIMPs. In this review article, we will focus on the function of cardiac fibroblasts in the context of ECM formation, homeostasis and remodeling in the heart. We will discuss the origins and multiple roles of cardiac fibroblasts in myocardial remodeling in different types of heart disease in patients and in animal models. We will further provide an overview of what we have learned from experimental animal models and genetically modified mice with altered expression of ECM regulatory proteins, MMPs and TIMPs.

Usefulness of circulating biomarkers for the prediction of left ventricular remodeling after myocardial infarction

Left ventricular (LV) remodeling after myocardial infarction (MI) indicates a high risk of heart failure and death, but LV remodeling remains difficult to predict. Biomarkers may help to refine risk stratification for a more personalized medical approach. They may also shed light on the pathophysiologic processes involved. We performed a systematic review of the published evidence about the association of circulating biomarkers with LV remodeling after MI. We selected 59 publications. Overall, these studies examined 112 relations between 52 different biomarkers and LV remodeling. The biomarkers most consistently associated with LV remodeling were involved in extracellular matrix turnover or neurohormonal activation: matrix metalloproteinase-9, collagen peptides, and B-type natriuretic peptide. This review underscores the vitality of the research on LV remodeling but concludes that the ideal biomarker has not yet been identified. To reach this goal, future studies will have to be larger, have standardized imaging end points, and include replication populations to define optimal cutoffs for LV remodeling prediction. Cardiovascular magnetic resonance appears to be the best technique for LV remodeling assessment but its current availability may be a concern for recruitment for multicenter studies. Recent technologic advances will probably yield new candidate biomarkers of LV remodeling. Tests are necessary to determine whether a multimarker approach would significantly improve risk prediction.

Tenascin-C in human cardiac pathology

Tenascin-C (TN-C), a hexameric extracellular matrix glycoprotein, is a pleiotropic regulator of a variety of cell functions associated with embryogenesis, wound healing, cell proliferation, differentiation, motility, and nerve regeneration. Due to its role in remodeling processes, TN-C is involved with many pathologic states including cardiac and vascular diseases as well as inflammation and cancer. Assessment of circulating TN-C may help with identification of heart disease, especially in conjunction other cardiac biomarkers. It may be considered a specific biomarker useful in detecting cardiac pathology, especially in early disease stages and subsequent monitoring of cardiologic therapy. This review will highlight the biochemistry and usefulness of TN-C in clinical laboratory diagnostics to date.

Circulating levels of soluble Fas ligand and left ventricular remodeling after acute myocardial infarction (from the REVE-2 study)

BACKGROUND

Apoptosis-related molecules may contribute to left ventricular (LV) remodeling after myocardial infarction (MI). To validate this hypothesis, we evaluated the relation between circulating plasma levels of soluble Fas ligand (sFas-L) and LV remodeling in patients post-MI.

METHODS AND RESULTS

This prospective multicenter study included 246 patients with a first anterior Q-wave MI. Serial echocardiographic studies were performed at hospital discharge and 3 and 12 months after MI; quantitative analysis was performed at a core echocardiography laboratory. Clinical follow-up was performed at 3 years post-MI. Blood samples to measure sFas-L were obtained at 1 month after MI. Median sFas-L level was 50.2 pg/mL. During the 1 year follow-up, LV remodeling was documented by a significant increase in LV volumes. LV end-diastolic and end-systolic volumes at baseline, 3 months, and 12 months after MI did not differ according to sFas-L levels; changes in LV volumes were not associated with sFas-L levels. By multivariate analysis, 2 variables were independently associated with LV remodeling: B-type natriuretic peptide (BNP) (p=0.008) and baseline ejection fraction (p=0.02). sFas-L levels were not associated with cardiovascular death or rehospitalization for heart failure at 3 years; conversely, high levels of BNP were associated with worse clinical outcome.

CONCLUSIONS

Soluble Fas-L levels are not associated with LV remodeling after MI. Further research is needed to identify apoptotic markers that may be associated with outcome post-MI.

The relationship between serum markers of collagen turnover and cardiovascular outcome in the elderly: the Cardiovascular Health Study

BACKGROUND

The deposition of collagen fibrils in the myocardial extracellular matrix increases with age and plays a key role in the pathophysiology of heart failure (HF). We sought to determine the predictive value of serum markers of collagen turnover for incident HF and cardiovascular (CV) morbidity, mortality, and all-cause mortality in elderly individuals.

METHODS AND RESULTS

In 880 participants in the Cardiovascular Health Study (mean age, 77±6 years; 48% women), serum levels of carboxyl-terminal peptide of procollagen type I (PIP), carboxyl-terminal telopeptide of collagen type I (CITP), and amino-terminal peptide of procollagen type III (PIIINP) were measured in 4 groups: HF with reduced ejection fraction (HFREF; n=146, EF <55%); HF with preserved EF (HFPEF; n=175, EF ≥55%), control subjects with CV risk factors but not HF (CVD; n=280), and healthy control subjects free of CV disease (n=279). Relationships between these serum markers and outcome at follow-up of 12±4 years (range, 3-17 years) was determined in six models including those adjusted for conventional risk factors, renal function, NT-proBNP and agents which interfere with collagen synthesis. For the entire cohort, in unadjusted and adjusted models, both PIIINP and CITP were associated with myocardial infarction, incident HF, hospitalization for HF, cardiovascular and all-cause mortality. In healthy control subjects, CITP and PIIINP were associated with all-cause death. In control subjects with risk factors, CITP was associated with incident HF, and in participants with HFPEF, CITP was associated with hospitalization for HF. No collagen biomarker was associated with outcome in participants with HFREF, and PIP was not associated with outcome in the cohort or its subgroups.

CONCLUSIONS

In both healthy and elderly individuals with CV disease at risk of developing HF, CITP and PIIINP are significantly associated with multiple adverse cardiac outcomes including myocardial infarction, HF, and death. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00005133.

Biomarkers: optimizing treatment guidance in heart failure

Heart failure is a frequent and life-threatening syndrome which is not only the result of myocardial injury or hemodynamic overload as commonly perceived, but appears to be the result of an interplay among genetic, neurohormonal, inflammatory, and biochemical factors, collectively referred to as biomarkers. Biomarkers can become risk factors in case their therapeutic modification results in an improvement of clinical outcomes. Among those markers identified in patients with heart failure, a number appears to have direct clinical relevance in aiding diagnosis, risk stratification, monitoring therapy, and treating to targets in order to improve clinical outcomes. These include brain natriuretic peptides (e.g., BNP, NT-proBNP), inflammatory markers (e.g., hsCRP), neurohormones (e.g., aldosterone), cardiorenal markers (e.g., cycstatin C), and novel markers (e.g., galectin-3). While their utility to indicate risk is mostly well established, there are less data to establish that a treatment using biomarkers as a guidance results in better outcomes than a more generalized intensified treatment of patients with heart failure. Future directions may involve larger platforms that facilitate to simultaneously analyze hundreds of biomarkers and may help to tailor heart failure therapy on a single patient basis, considering the specific pathogenesis and prognosis. Also from a therapeutic perspective there are data that a single intervention such as aldosterone blockade may affect multiple biomarkers at the same time. Taken together the data indicate that biomarkers are evolving into a valuable addendum to the diagnostic and therapeutic armamentarium.

Evaluation of early biomarkers of muscle anabolic response to testosterone

BACKGROUND: Early biomarkers of skeletal muscle anabolism will facilitate the development of therapies for sarcopenia and frailty. METHODS AND RESULTS: We examined plasma type III collagen N-terminal propeptide (P3NP), skeletal muscle protein fractional synthesis rate, and gene and protein expression profiles to identify testosterone-induced changes in muscle anabolism. Two placebo-controlled studies enrolled community-dwelling men (study 1, 60-75 years; study 2, 18-40 years) with low to normal testosterone levels. Men were randomized to lower dose (study 1, 100 mg; study 2, 200 mg) or higher dose (study 1, 300 mg; study 2, 600 mg) single intramuscular testosterone or saline injection. After 1 week, testosterone acutely increased plasma P3NP levels in a dose-dependent manner and altered the expression of several skeletal muscle transcripts and proteins. Though not statistically significant, mixed muscle protein fractional synthesis rate tended to increase (1.08-fold with 100 mg testosterone, 1.12-fold with 300 mg testosterone). Testosterone exposure also increased skeletal muscle expression of the collagen type III gene that encodes P3NP. CONCLUSION: P3NP is a potentially useful early biomarker for muscle anabolic therapy. Skeletal muscle protein and RNA profiling are useful tools for the discovery of novel muscle anabolic biomarkers.

Procollagen III N-terminal peptide predicts short-term prognosis and cardiac remodeling in coronary heart disease patients with metabolic syndrome

INTRODUCTION

Many patients with coronary heart disease (CHD) also have metabolic syndrome (MS); however, little is known about the condition of cardiovascular remodeling in these patients. The objective of this study to explore the role of plasma procollagen III N-terminal peptide (PIIINP) in predicting the prognosis and cardiac remodeling in patients with CHD with MS.

METHODS

One hundred eight patients were classified into high and low PIIINP groups according to the median value of plasma PIIINP. Cardiovascular examinations including echocardiogram, carotid color ultrasound examination, coronary angiography and the 6-minute walking test (6MWT) were performed before and after a 1-year follow-up. Readmission for cardiac and cerebrovascular events was assessed during the follow-up period.

RESULTS

Plasma PIIINP level was significantly correlated with age, high-sensitivity C-reactive protein (hs-CRP) and body mass index in a multiple stepwise regression model. There was a positive correlation between the LnPIIINP and an increased left ventricular mass index in partial correlation analysis. The Cox proportional hazard model analysis indicated that the level of PIIINP, left ventricular ejection fraction and hs-CRP were independent predictors of readmission owing to cardiac and cerebrovascular events during the follow-up. A PIIINP value of 4.0 μg/L was the best threshold value for determining the need for readmission.

CONCLUSIONS

PIIINP levels rise with increases in age, hs-CRP and body mass index in patients with CHD with MS, and a high level of PIIINP indicates recent deterioration of cardiac remodeling and exercise tolerance and a poor prognosis.

Serum procollagen type III is associated with elevated right-sided filling pressures in stable outpatients with congestive heart failure

Elevated filling pressures are associated with heart failure deterioration, but mechanisms underlying this association remain poorly understood. We sought to investigate whether or not elevated filling pressures are associated with increased collagen turnover, evaluated by procollagen type III aminoterminal peptide (PIIINP) levels, in stable systolic heart failure. Eighty patients with heart failure with severe systolic dysfunction (ejection fraction 26 +/- 7%) were included. Patients underwent simultaneous echocardiogram with evaluation of haemodynamic parameters and blood sampling for PIIINP measurement. Mean PIIINP level was 6.11 +/- 2.62 microg l(-1). PIIINP was positively associated with estimated right atrial pressure (RAP) (r = 0.36; p = 0.001). Mean PIIINP values were 5.04 +/- 2.42 microg l(-1) in patients with estimated RAP < or = 5 mmHg, and 7.59 +/- 2.54 microg l(-1) in those with RAP > 15 mmHg (p < 0.01). In conclusion, elevated right-side filling pressures are associated with evidence of active extracellular matrix turnover, as indicated by elevated PIIINP levels, in stable systolic heart failure. Activation of extracellular matrix turnover may be implicated in the accelerated progression of heart failure syndromes seen in patients with persistent congestion.

Biomarkers of extracellular matrix turnover

The extracellular cardiac matrix (ECCM) plays an important role in the support of myocytes and fibroblasts. ECCM turnover is influenced by ischemia, stretch, inflammation, and neurohormonal mediators. Myocardial fibrosis is the consequence of several pathologic processes mediated by mechanical, neurohormonal, and cytokine factors. It is a major determinant of diastolic dysfunction and pumping capacity and may result in tissue heterogeneity, dys-synchrony, and arrhythmias. The measurement of various serum peptides arising from the metabolism of collagen types 1 and 3, of degradation fragments, and of specific metalloproteinases may provide noninvasive assessment of fibrosis. ECCM biomarkers are clinically useful tools, particularly given the potential for cardioprotective and cardioreparative pharmacologic strategies.

Cross-sectional relations of multiple biomarkers representing distinct biological pathways to plasma markers of collagen metabolism in the community

OBJECTIVE

Hyperhomocysteinemia, neurohormonal activation, inflammation and altered fibrinolysis have been linked to atherothrombosis as well as to myocardial fibrosis and heart failure. Hence, we related a panel of biomarkers representing these pathways to plasma markers of collagen metabolism in a large community-based sample.

METHODS

We related nine biomarkers representing select biologic pathways (independent variables: C-reactive protein, B-type natriuretic peptide, N-terminal proatrial natriuretic peptide, aldosterone, renin, fibrinogen, D-dimer, plasminogen activator inhibitor-1 and homocysteine) to three plasma markers of collagen turnover [dependent variables, separate models for each: aminoterminal propeptide of type III collagen, tissue inhibitor of metalloproteinases-1 and matrix metalloproteinase-9 (present versus absent)] in 921 Framingham Heart study participants (mean age 57 years; 58% women). Participants were separated a priori into those with left ventricular end-diastolic dimensions and wall thickness below sex-specific median values (referent group) and either measure at least 90th sex-specific percentile ('remodeled' group). We used stepwise multivariable regression analysis adjusting for cardiovascular risk factors to relate the panel of systemic biomarkers to the three biomarkers of collagen metabolism.

RESULTS

Plasma homocysteine was positively related to all three markers of collagen metabolism in the remodeled group and to aminoterminal propeptide of type III collagen and tissue inhibitor of metalloproteinases-1 in the referent group. Plasminogen activator inhibitor-1 was positively related to aminoterminal propeptide of type III collagen and tissue inhibitor of metalloproteinases-1 in both groups, whereas the natriuretic peptides were associated positively with these collagen markers in the referent group.

CONCLUSION

In our large community-based sample, plasma homocysteine and plasminogen activator inhibitor-1 were positively related to circulating collagen biomarkers, consistent with experimental studies implicating these pathways in cardiovascular collagen turnover.

Effect of pioglitazone on left ventricular diastolic function and fibrosis of type III collagen in type 2 diabetic patients

BACKGROUND

Myocardial fibrosis is the major factor that regulates left ventricular (LV) diastolic function. Pioglitazone, an anti-diabetic drug, is reported to improve the LV diastolic function in diabetic patients, but its influence on myocardial fibrosis has not been clarified. We evaluated the effect of pioglitazone on LV diastolic function and myocardial fibrosis in type 2 diabetic (T2DM) patients.

METHODS AND RESULTS

Fifteen T2DM patients were enrolled in the ON group, and the parameters were examined before and after pioglitazone administration (15-30 mg/day) for 6 months. Twenty-four T2DM patients were assigned to the OFF group, and the parameters were examined before and 6 months after cessation of pioglitazone. We measured echocardiographic parameters such as early diastolic mitral annular velocity (E') and plasma concentration of aminoterminal propeptide of procollagen type III (PIIIP), a marker of myocardial fibrosis. In the ON group, pioglitazone significantly increased E' (6.04+/-1.70 cm/s vs. 6.51+/-1.64 cm/s, p<0.01) and decreased PIIIP (0.553+/-0.056 U/ml vs. 0.517+/-0.072 U/ml, p<0.05). There was a significant negative correlation between the change in PIIIP and the change in E' (r=-0.424, p=0.046). On the other hand, E' was significantly decreased (5.69+/-1.34 cm/s vs. 4.97+/-1.20 cm/s, p<0.01) in the OFF group. PIIIP was not significantly changed in the OFF group, but there was a significant negative correlation between the change in PIIIP and the change in E' (r=-0.374, p=0.035).

CONCLUSION

Six months of pioglitazone administration suppressed the synthesis of type III collagen, and this was associated with improved LV diastolic function in T2DM patients. Cessation of pioglitazone weakened the suppression of the synthesis of type III collagen, which in turn seemed to be associated with worse LV diastolic function.

Serum levels of YKL-40 increases in patients with acute myocardial infarction

OBJECTIVES

YKL-40 is secreted by macrophages, including those in atherosclerotic plaques, neutrophils, and vascular smooth muscle cells. Circulating YKL-40 is elevated in patients with inflammation and increased tissue remodeling. The aim was to examine the sequential changes in serum YKL-40 in patients with acute myocardial infarction (AMI), with and without thrombolytic therapy, as compared with patients with stable coronary artery disease (CAD).

METHODS

YKL-40 was measured by radioimmunoassay in serum from 63 patients. A total of 47 patients had their first AMI [30 with ST segment elevation myocardial infarction (STEMI) were thrombolyzed, 17 with non-STEMI were not thrombolyzed] and 16 patients had CAD.

RESULTS

Serum YKL-40 at the time of admission was higher in patients with AMI (median: 156 microg/l, range: 40-3000 microg/l) than in patients with CAD (median: 106 microg/l, range: 54-300 microg/l, P=0.048) and healthy participants (median: 102 microg/l, range: 38-514 microg/l, P<0.001). No difference in serum YKL-40 between CAD patients and healthy participants (P=0.89) was observed. No difference in serum YKL-40 between the AMI patients with or without ST-elevations (P=0.12) was observed. The maximum serum YKL-40 during the first 24 h after admission was higher in thrombolyzed STEMI patients than in the nonthrombolyzed, non-STEMI patients (P=0.01) and the CAD patients (P<0.0001). Serum YKL-40 declined consistently from the maximum value just after the AMI and during follow-up. Serum YKL-40 at 90, 180, and 360 days after AMI were significantly higher in nonthrombolyzed than in thrombolyzed patients (P=0.004, P=0.008, P=0.017, respectively).

CONCLUSION

These results demonstrated that serum concentrations of YKL-40 are greatly increased in AMI patients with and without thrombolytic therapy.

Diastolic Dysfunction After an Acute Myocardial Infarction in Patients with Antecedent Hypertension

OBJECTIVE

We sought to assess changes in the left ventricular systolic and diastolic function in patients with antecedent hypertension and an acute myocardial infarction.

METHODS

A group of 38 patients with antecedent hypertension and acute myocardial infarction were compared with an age-matched nonhypertensive control group. There was a 30-day follow-up. Outcome measures were left ventricular volumes and ejection fraction, systolic velocities, and strain. Diastolic function was assessed by mitral inflow combined with tissue velocities of the mitral ring.

RESULTS

Patients with antecedent hypertension did not experience any regression in the E/E' ratio (16.5 +/- 7.5 vs 17.1 +/- 9.0, P = not significant) or increase in the E'/A' ratio (0.76 +/- 0.5 vs 0.84 +/- 0.6, P = not significant) compared with significant improvements in E/E' ratio (18.9 +/- 8.7 vs 12.8 +/- 7.4, P < .01) and E'/A' ratio (0.76 +/- 0.5 vs 1.1 +/- 0.7, P < .01) in the control group. This was found despite similar changes ejection fraction, volumes, and systolic strain.

CONCLUSIONS

Patients with antecedent hypertension have incomplete improvement of the diastolic function compared with control subjects despite comparable left ventricular volumes and ejection fraction after an acute myocardial infarction.

Clinical and echocardiographic correlates of plasma procollagen type III amino-terminal peptide levels in the community

BACKGROUND

Left ventricular remodeling is characterized by increased collagen deposition in the extracellular matrix. Levels of plasma procollagen type III amino-terminal peptide (PIIINP), a marker of collagen turnover, are elevated in the setting of recent myocardial infarction, heart failure, and cardiomyopathy. Whether plasma PIIINP levels are a useful indicator of subclinical left ventricular abnormalities in ambulatory individuals has not been studied.

METHODS

We examined 967 Framingham Heart Study participants (mean age, 56 years; 60% women) who underwent routine echocardiography and measurement of plasma PIIINP levels. All participants were free of prior myocardial infarction or heart failure. Multivariable regression analyses were performed to examine the clinical and echocardiographic correlates of PIIINP levels.

RESULTS

Plasma PIIINP levels increased with age and body mass index but did not significantly correlate with other cardiovascular risk factors including hypertension and diabetes. In multivariable models, there was no association between plasma PIIINP levels and left ventricular mass (P = .89), left ventricular fractional shortening (P = .15), left ventricular end-diastolic dimension (P = .51), or left atrial size (P = .68). Plasma PIIINP levels were positively correlated with tissue inhibitor of metalloproteinase-1 levels (multivariable-adjusted, P = .001).

CONCLUSIONS

The use of biomarkers of extracellular matrix turnover has generated recent interest, with plasma PIIINP being the most commonly studied biomarker in acute settings. However, our findings in a large, community-based cohort suggest that plasma PIIINP has limited use for the detection of structural heart disease in ambulatory individuals.

Imaging of matrix metalloproteinase activation and left ventricular remodeling

Although left ventricular (LV) remodeling may be adaptive in early phases of cardiac injury, continued remodeling is a pathologic process that is associated with poor prognosis and diminished cardiac function. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes involved in the degradation of myocardial extracellular proteins and have been implicated in adverse cardiac remodeling. There is a growing body of literature that supports the role of specific MMPs in cardiac remodeling in both animal models and clinical studies. Conventional imaging of physiologic indices, such as perfusion and function, have been used to monitor LV remodeling. Recently, the potential advantage of targeted imaging of MMPs has been demonstrated, particularly if this is linked with physiologic imaging.

Residual stress ischaemia is associated with blood markers of myocardial structural remodelling

BACKGROUND

Long-term prognosis of coronary artery disease (CAD) patients is worsened when stress ischemia persists on treatment, but the relationship with adverse cardiac remodelling had never been investigated.

AIM

To analyze changes in blood markers of fibrosis in patients with chronic CAD exhibiting exercise ischaemia.

METHODS

Circulating markers of collagen: (i) turnover (amino-terminal propeptide of collagen-III [PIIINP]) and (ii) degradation (matrix metalloproteinase 1 [MMP-1]), were obtained in 139 CAD patients referred for exercise 201Tl-SPECT.

RESULTS

In the 57 patients who had SPECT-ischaemia, PIIINP was higher (4.3+/-2.9 microg L-1 vs. 3.1+/-1.5 microg L-1, p=0.002) and MMP-1 lower (3.8+/-2.1 microg L-1 vs. 4.7+/-2.8 microg L-1, p=0.04) than in the 82 patients without SPECT-ischaemia. PIIINP was independently related to LV volume, SPECT-ischaemia and age, whereas MMP-1 was related to current treatment with ACEI and beta-blockers (p<0.05). In the 104 patients with a normal LV ejection fraction, only PIIINP was related to SPECT-ischaemia (4.1+/-2.2 microg L-1 vs. 3.1+/-1.5 microg L-1, p=0.01).

CONCLUSION

In patients with chronic CAD, exercise ischaemia is associated with increased collagen-III turnover, independently of concomitant medications and even when LV ejection fraction is normal. Long-term, this increase might relate to adverse cardiac remodelling even when cardiac function is not clearly affected at baseline.

Association of amino-terminal propeptide of type III procollagen and acute myocardial rejection in male patients receiving heart transplantation

BACKGROUND

The amino-terminal propeptides of type I and III procollagens (PINP and PIIINP) are markers reflecting the status of collagen turnover. We hypothesized that measurement of these serum procollagen propeptides could be used to non-invasively assess acute rejection in heart transplant recipients.

METHODS

In heart transplant recipients, endomyocardial biopsy specimens taken at 6 and 12 months after surgery were used for study. PINP and PIIINP were measured postoperatively at 3, 6, and 12 months.

RESULTS

A total of 20 male heart transplant patients and seven male control subjects were enrolled. Five patients showed rejection 6 months after transplantation (group 1), while 15 patients showed no rejection (group 2). In group 2 patients, serum PINP and PIIINP levels decreased significantly 6 months after transplantation. In contrast, elevation of serum PINP and PIIINP levels persisted in group 1 patients 6 months after transplantation. At 6 months after transplantation, group 1 patients had significantly higher PIIINP levels than group 2 patients (p=0.025) and controls (p=0.003). After immunosuppressive therapy, all group 1 patients were free of rejection 12 months after transplantation and serial serum PIIINP levels decreased significantly in these patients.

CONCLUSIONS

Serum PIIINP levels represent a non-invasive method to reflect the occurrence and resolution of acute rejection.

Cardiac Troponin T vs Other Biochemical Markers in Patients With Congestive Heart Failure

BACKGROUND

Several pathologic processes can cause myocardial injury, which is followed by cardiac remodeling and congestive heart failure (CHF). Cardiac troponin T (cTnT), a specific and sensitive marker of myocardial injury, has been related to long-term outcome in patients with CHF, so the relationship between cTnT and other biochemical markers associated with the pathophysiology of CHF was investigated in the present study.

METHODS AND RESULTS

Between February 2004 and December 2005, 145 consecutive hospitalized patients (mean left ventricular ejection fraction (LVEF) 31.6+/-0.9%) with CHF were divided into low (<0.01 ng/ml) and high (> or =0.01 ng/ml) serum cTnT groups. Correlations with other prognostic biochemical markers, including brain natriuretic peptide (BNP), type I collagen C-terminal telopeptide (ICTP), procollagen type III peptide (PIIIP), renin, norepinephrine (NOREPI), C-reactive protein (CRP), cholesterol, hemoglobin (Hb), uric acid and HbA1c were examined. cTnT was high in 46 (32%) and low in 99 (68%) patients at baseline. Patients with high cTnT had abnormally high blood concentrations of BNP (p<0.0001), ICTP (p<0.0001), PIIIP (p=0.0006), NOREPI (p=0.0119), CRP (p=0.0003), uric acid (p=0.0026) and HbA1c (p=0.0361). In contrast, concentrations of cholesterol and Hb were significantly lower in patients with high cTnT (p=0.0319 and 0.0005, respectively). Death from or rehospitalization for CHF occurred in 41% in the high vs 9% in the low cTnT group (p=0.0002). Univariate analysis showed that high cTnT (p=0.0005), BNP (p=0.0001), renin (p=0.0158), NOREPI (p=0.0094), old age (p=0.0390), low LVEF (p=0.0231) and high New York Heart Association (NYHA) class (p=0.0006) were predictors of death from or rehospitalization for CHF. By multivariate analysis including BNP, NOREPI, age, LVEF and NYHA class, high cTnT and renin remained as significant predictors.

CONCLUSIONS

Patients with ongoing myocardial injury and high cTnT had associated findings consistent with activation of the sympathetic system, synthesis of cardiac fibrosis, inflammation and metabolic abnormalities. By multivariate analysis, high cTnT and renin remained significant predictors of death or rehospitalization.

Temporal increases in subclinical levels of inflammation are associated with adverse clinical outcomes in patients with left ventricular dysfunction

BACKGROUND

The implication of various cytokines in a subclinical inflammatory process has been documented in heart failure (HF). The role of temporal changes of more conventional markers of inflammation, such as the white blood cell (WBC) count, on clinical outcomes remains largely unknown.

METHODS AND RESULTS

We performed a retrospective analysis of patients included in the Studies Of Left Ventricular Dysfunction that had documented eligibility at the baseline visit, a documented WBC count at baseline and at least 1 measurement during follow-up. We evaluated the association between variations in WBC count, WBC subfractions and mortality and non-fatal events. An increase in WBC count during follow-up compared with baseline was associated with a significantly higher risk of all-cause and cardiovascular (CV) mortality, HF mortality and arrhythmic death (all P < .05). A relative increase in the neutrophil count was associated with higher risk of all-cause and CV mortality, HF mortality and cardiac ischemic events (all P < .05). No significant interaction was present in regards to the etiology of HF.

CONCLUSIONS

Temporal increases in WBC and neutrophil counts are associated with increased risks of death and CV events. This relationship appears to be independent of HF etiology.

Remodelado miocárdico y activación inmunitaria en pacientes con insuficiencia cardiaca

INTRODUCTION AND OBJECTIVES

Immune response-mediated regulation of myocardial collagen remains poorly understood. Our objective was to investigate the relationship between ventricular remodeling and immunologic activation in patients with heart failure (HF) by comparing dilated and ischemic cardiomyopathy.

METHODS

We studied 94 patients with HF and dilated cardiomyopathy (n=46) or ischemic cardiomyopathy (n=48). We recorded left ventricular (LV) volumes, E/A ratio, and ejection fraction. Plasma concentrations of tumor necrosis factor alpha (TNFalpha), soluble TNFa receptor I (sTNF-RI), sTNF-RII, interleukin-6 (IL-6) and IL-10 were measured. The serum procollagen type-III amino-terminal propeptide (PIIINP) level was also obtained.

RESULTS

Ventricular volumes were greater in the dilated cardiomyopathy than in the ischemic cardiomyopathy group (P< .05). However, sTNF-RI, sTNF-RII and PIIINP levels were higher in the ischemic group (P< .05). In this group, there were significant correlations between ventricular volumes and IL-10 and sTNF-RII levels. There was also a significant correlation between PIIINP and sTNF-RII levels (r=0.30; P< .05). In the dilated cardiomyopathy group, there was a significant correlation between ventricular volumes and IL-10 level, and between PIIINP level and IL-6 (r=0.32; P< .05) and sTNF-RII levels (r=0.32; P< .05). Multiple linear regression analysis, which included cytokine levels, age, sex and ventricular function, showed that the sTNF-RII level was an independent predictor of the PIIINP level (adjusted r(2)=0.16; P< .0001) and of ventricular volumes (LV end-systolic volume index, adjusted r(2)=0.034; P< .05; and LV end-diastolic volume index, adjusted r(2)=.048; P< .05) in both groups.

CONCLUSIONS

In HF, there is an interaction between proinflammatory cytokines and the extracellular matrix. Immunologic implications vary according to disease etiology. The elevation in proinflammatory cytokine and PIIINP levels is greater in patients with ischemic cardiomyopathy. Multiple regression analysis showed that the sTNF-RII level was an independent predictor of ventricular remodeling.