Collagen Turnover Markers in Relation to Future Cardiovascular and Noncardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

Predictive Value of Collagen Biomarkers in Advanced Chronic Kidney Disease Patients

Patients with chronic kidney disease have an increased risk of all-cause death. The value of collagen biomarkers such as procollagen type I carboxy-terminal propeptide (PICP) and procollagen type III N-terminal peptide (P3NP), in end-stage renal disease (ESRD), has not yet been defined (in the literature and in clinics). The purpose of this study was to determine the potential value of these new biomarkers in the prediction of mortality in this population. Plasma PICP and P3NP levels were determined in 140 patients with ESRD, not yet on dialysis, who were followed up for 36 ± 5.3 months. During follow-up, 58 deaths were recorded (41.4%), with the majority of them being cardiovascular deaths (43, 74.13%). Using the ROC curve, the cut-off value for the prediction of mortality for PICP was 297.31 µg/L, while for P3NP, the cut-off value was 126.67 µg/L. In univariate analysis, a value of PICP above the cut-off point was associated with a fivefold increased risk of mortality (hazard ratio (HR) 5.071, 95% confidence interval 1.935-13.29, p = 0.001) and a value of P3NP above the cut-off point was associated with a twofold increased risk of mortality (HR 2.089, 95% CI 1.044-4.178, p = 0.002). In a multivariable Cox proportional hazards model, PICP values remained independent predictors of mortality (HR 1.22, 95% CI 1.1-1.31, p < 0.0001). Our data suggest that the collagen biomarker PICP is an independent predictor of mortality in ESRD patients who are not yet on dialysis.

Biomarkers, Socioeconomic Factors, and Right Ventricular Function After Surgical Repair for Tetralogy of Fallot

Right ventricular (RV) dysfunction early after tetralogy of Fallot (TOF) increases post-operative morbidity. We investigated associations of circulating biomarkers and socioeconomic factors with early post-operative RV systolic function. Single-center prospective cohort study of infants undergoing TOF repair. Six serologic biomarkers of myocardial fibrosis and wall stress collected at the time of surgery were measured with immunoassay. Geocoding was performed for socioeconomic factors. Multivariate adaptive regression splines (MARS) models identified factors associated with RV function parameters: fractional area change (FAC), global longitudinal strain and strain rate, and free wall strain and strain rate. Seventy-one patients aged 3.5 months (IQR 2.4, 5.2) were included. Galectin-3 was the highest ranked predictor for FAC, global longitudinal strain, and free wall strain, and procollagen type-I carboxy-terminal propeptide (PICP) was the highest ranked predictor for global longitudinal strain rate and free wall strain rate. Several neighborhood characteristics were also highly ranked. Models adjusted R² ranged from 0.71 to 0.85 (FAC, global longitudinal strain/strain rate), and 0.55-0.57 (RV free wall strain/strain rate). A combination of serologic biomarkers, socioeconomic, and clinical variables explain a significant proportion of the variability in RV function after TOF repair. These factors may inform pre-operative risk-stratification for these patients.

Aging and its treatment with vitamin C: a comprehensive mechanistic review

Aging and age-related disorders have become one of the prominent issue of world. Oxidative stress due to overproduction of reactive oxygen species is the most significant cause of aging. The aim of literature compilation was to elucidate the therapeutic effect of vitamin C against oxidative stress. Various mediators with anti-inflammatory and anti-oxidant properties might be probable competitors of vitamin C for the improvement of innovative anti-aging treatments. More attention has been paid to vitamin C due to its anti-oxidant property and potentially beneficial biological activities for inhibiting aging.Vitamin C acts as an antioxidant agent and free radical scavenger that can protect the cell from oxidative stress, disorganization of chromatin, telomere attrition, and prolong the lifetime. This review emphasizes mechanism of aging and various biomarkers that are directly related to aging and also focuses on the therapeutic aspect of vitamin C against oxidative stress and age-related disorders.

Role of collagen turnover biomarkers in the noninvasive assessment of myocardial fibrosis: an update

The pro-fibrotic milieu, as the result of the extracellular matrix remodeling, is a central feature in the pathophysiology of heart disease and contributes to its high morbidity and mortality. Fibrosis is a recognized risk factor for development of heart failure and arrythmias and is usually detected by cardiac magnetic resonance or endomyocardial biopsy. Collagen type I and type III are major components of the collagen network, and the assessment of their derived biomarkers could serve as estimate of the myocardial fibrotic content. This review summarizes data from numerous studies in which these biomarkers have proven their diagnostic and prognostic utility, setting the stage for further randomized clinical trials that might translate into early implementation of antifibrotic therapies.

Biomarker of Collagen Turnover (C-Terminal Telopeptide) and Prognosis in Patients With Non- ST -Elevation Acute Coronary Syndromes

Background

Small studies have suggested an association between markers of collagen turnover and adverse outcomes in heart failure (HF). We examined C‐terminal telopeptide (beta‐CTx) and the risk of cardiovascular death or new or worsening HF in non–ST‐elevation acute coronary syndrome.

Methods and Results

We measured baseline serum beta‐CTx, NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), hsTnT (high‐sensitivity cardiac troponin T) and hsCRP (high‐sensitivity C‐reactive protein) (Roche Diagnostics) in a nested biomarker analysis (n=4094) from a study of patients with non–ST‐elevation acute coronary syndrome. The relationship between quartiles of beta‐CTx and cardiovascular death or HF over a median follow‐up time of 12 months was analyzed using adjusted Cox models. Higher beta‐CTx levels identified a significantly higher risk of cardiovascular death/HF (Q4 10.9% versus Q1 3.8%, Logrank P<0.001). After multivariable adjustment, beta‐CTx in the top quartile (Q4) was associated with cardiovascular death/HF (Q4 versus Q1: adjusted hazard ratio 2.22 [1.50–3.27]) and its components (Q4 versus Q1: cardiovascular death: adjusted hazard ratio 2.48 [1.46–4.21]; HF: adjusted hazard ratio 2.04 [1.26–3.30]). In an adjusted multimarker model including NT‐proBNP, hsTnT, and hsCRP, beta‐CTx remained independently associated with cardiovascular death/HF (Q4 versus Q1: adjusted hazard ratio 1.98 [1.34–2.93]) and its components. Beta‐CTx correlated weakly with NT‐proBNP (r=0.17, P<0.001) and left ventricular ejection fraction (r=−0.05, P=0.008) and did not correlate with hsTnT (r=0.02, P=0.20), or hsCRP (r=−0.03, P=0.09).

Conclusions

Levels of beta‐CTx, a biomarker of collagen turnover, were associated with cardiovascular death and HF in patients with non–ST‐elevation acute coronary syndrome. This biomarker, which correlated only weakly or not significantly with traditional biomarkers of cardiovascular death and HF, may provide complementary pathobiological insight and risk stratification in these patients.

Collagen biomarkers are associated with decline in renal function independently of blood pressure and other cardiovascular risk factors: the Multi-Ethnic Study of Atherosclerosis Study

OBJECTIVE

We studied associations of circulating collagen type I carboxy-terminal telopeptide (ICTP) and procollagen type III N-terminal propeptide (PIIINP) with long-term renal function decline.

METHODS

In the Multi-Ethnic Study of Atherosclerosis, we included 2492 participants initially aged 45-84 years and free of clinical cardiovascular disease (CVD), excluding people with estimated glomerular filtration rate (eGFR) less than 60 ml/min per 1.73 m or urine albumin/creatinine (UAC) at least 30 mg/g. The primary outcome in median 9.4-year follow-up was renal function decline (≥30% decline in eGFR between any two exams or incident UAC ≥ 30 mg/g). The associations of baseline plasma ICTP and PIIINP with renal function decline were estimated using Poisson regression, adjusting for baseline variables race/ethnicity, sex, age, and continuous eGFR and UAC, with further adjustment for CVD risk factors and medications.

RESULTS

Baseline serum ICTP was 3.27 ± 1.43 μg/l and PIIINP was 5.43 ± 1.85 μg/l. Mean baseline eGFR was 91.5 ± 18.4 ml/min per 1.73 m. Renal function decline occurred in 19.5% during 9.4-year follow-up. The renal function decline outcome was positively associated with serum ICTP and PIIINP: relative incidence density (95% confidence interval) per SD 1.22 (1.11-1.33) and 1.27 (1.16-1.40), respectively. Additional adjustment for other risk factors did not greatly alter findings.

CONCLUSION

High collagen biomarker concentrations in serum were associated with future decline in renal function in people initially free of CVD and with normal eGFR, consistent with collagen production signaling renal decline. The continuous association observed for ICTP which, unlike PIIINP, is filtered by the kidney, may owe to its double status as a sensitive marker of glomerular function and collagen degradation.

Exploring the role of extracellular matrix proteins to develop biomarkers of plaque vulnerability and outcome

Cardiovascular disease (CVD) is the most common cause of death in industrialized countries. One underlying cause is atherosclerosis, which is a systemic disease characterized by plaques of retained lipids, inflammatory cells, apoptotic cells, calcium and extracellular matrix (ECM) proteins in the arterial wall. The biologic composition of an atherosclerotic plaque determines whether the plaque is more or less vulnerable, that is prone to rupture or erosion. Here, the ECM and tissue repair play an important role in plaque stability, vulnerability and progression. This review will focus on ECM remodelling in atherosclerotic plaques, with focus on how ECM biomarkers might predict plaque vulnerability and outcome.

Geometry of the Carotid Artery and Its Association With Pathologic Changes in a Chinese Population

Objectives

Carotid artery geometry influences blood flow disturbances and is thus an important risk factor for carotid atherosclerosis. Extracellular matrix (ECM) and yes-associated protein (YAP) expression may play essential roles in the pathophysiology of carotid artery stenosis, but the effect of blood flow disturbances of carotid bifurcation location on the ECM is unknown. We hypothesized that carotid artery anatomy and geometry are independently associated with the ECM and YAP expression.

Methods

In this cross-sectional study, 193 patients were divided into two groups: an asymptomatic group (n = 111) and a symptomatic group (n = 82), symptomatic patients presenting with ischemic attack, amaurosis fugax, or minor non-disabling stroke. For all subjects before surgery, carotid bifurcation angle and internal artery angle were measured with computed tomography angiography (CTA), and laminar shear stress was measured with ultrasonography. After surgery, pathology of all plaque specimens was analyzed using hematoxylin and eosin (HE) staining and Movat special staining. Immunohistochemistry was performed to detect expression of YAP in a subset of 30 specimens.

Results

Symptomatic patients had increased carotid bifurcation angle and laminar shear stress compared to asymptomatic patients (P < 0.05), although asymptomatic patients had increased internal carotid angle compared to symptomatic patients (P < 0.001). Relative higher bifurcation angles were correlated with increased carotid bifurcation, decreased internal angle, and decreased laminar shear stress. For each change in intervertebral space or one-third of vertebral body height, carotid bifurcation angle changed 4.76°, internal carotid angle changed 6.91°, and laminar shear stress changed 0.57 dynes/cm². Pathology showed that average fibrous cap thickness and average narrowest fibrous cap thickness were greater in asymptomatic patients than symptomatic patients (P < 0.05). Expression of proteoglycan and YAP protein in symptomatic patients was higher than in asymptomatic patients (P < 0.001), while collagen expression was lower in symptomatic patients than asymptomatic patients (P < 0.05).

Conclusion

Geometry of the carotid artery and position relative to cervical spine might be associated with ECM and YAP protein expression, which could contribute to carotid artery stenosis.

The urinary proteomics classifier chronic kidney disease 273 predicts cardiovascular outcome in patients with chronic kidney disease

Background

The urinary proteomic classifier chronic kidney disease 273 (CKD273) is predictive for the development and progression of chronic kidney disease (CKD) and/or albuminuria in type 2 diabetes. This study evaluates its role in the prediction of cardiovascular (CV) events in patients with CKD Stages G1–G5.

Methods

We applied the CKD273 classifier in a cohort of 451 patients with CKD Stages G1–G5 followed prospectively for a median of 5.5 years. Primary endpoints were all-cause mortality, CV mortality and the composite of non-fatal and fatal CV events (CVEs).

Results

In multivariate Cox regression models adjusting for age, sex, prevalent diabetes and CV history, the CKD273 classifier at baseline was significantly associated with total mortality and time to fatal or non-fatal CVE, but not CV mortality. Because of a significant interaction between CKD273 and CV history (P = 0.018) and CKD stages (P = 0.002), a stratified analysis was performed. In the fully adjusted models, CKD273 classifier was a strong and independent predictor of fatal or non-fatal CVE only in the subgroup of patients with CKD Stages G1–G3b and without a history of CV disease. In those patients, the highest tertile of CKD273 was associated with a &gt;10-fold increased risk as compared with the lowest tertile.

Conclusions

The urinary CKD273 classifier provides additional independent information regarding the CV risk in patients with early CKD stage and a blank CV history. Determination of CKD273 scores on a random urine sample may improve the efficacy of intensified surveillance and preventive strategies by selecting patients who potentially will benefit most from early risk management.

Collagen Biomarkers and Incidence of New Onset of Atrial Fibrillation in Subjects With No Overt Cardiovascular Disease at Baseline: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Atrial fibrosis is a hallmark of structural remodeling in atrial fibrillation (AF). Plasma procollagen type III N-terminal propeptide (PIIINP) reflects collagen synthesis and degradation while collagen type I carboxy-terminal telopeptide (ICTP) reflects collagen degradation. We aimed to study baseline plasma PIIINP and ICTP and their associations with incident AF in participants initially free of overt cardiovascular disease.

METHODS

In a stratified sample of the Multi-Ethnic Study of Atherosclerosis, initially aged 45-84 years, 3071 participants had both PIIINP and ICTP measured at baseline. Incident AF in 10-year follow-up was based on a hospital International Classification of Diseases code for AF or atrial flutter, in- or outpatient Medicare claims through 2011 (primarily in those aged 65-84 years), or ECG 10 years after baseline (n=357). The associations of PIIINP and ICTP with incident AF were estimated using Poisson regression with follow-up time offset.

RESULTS

Baseline PIIINP (5.50±1.55 µg/L) and ICTP (mean±SD, 3.41±1.37 µg/L) were positively related (both P<0.0001) to incident AF in a model adjusting for age, race/ethnicity, and sex, with an apparent threshold (relative incidence density 2.81 [1.94-4.08] for PIIINP ≥8.5 µg/L [3.5% of the sample] and 3.46 [2.36-5.07] for ICTP ≥7 µg/L [1.7% of the sample]). Findings were attenuated but remained statistically significant after further adjustment for systolic blood pressure, height, body mass index, smoking, and renal function. Additional adjustment for other risk factors and biomarkers of inflammation did not alter conclusions.

CONCLUSIONS

Plasma collagen biomarkers, particularly at elevated levels, were associated with excess risk for AF.

Collagen biomarkers predict new onset of hypertension in normotensive participants: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Vascular remodeling associated with increased extracellular matrix (ECM) may precede hypertension. Procollagen type III N-terminal propeptide (PIIINP) and collagen type I carboxy-terminal telopeptide (ICTP) reflect collagen turnover and are important in ECM remodeling. PIIINP and ICTP are increased in cardiovascular diseases (CVD). We hypothesized that PIIINP and ICTP among normotensives predict incident hypertension.

METHODS

We included 1252 Multi-Ethnic Study of Atherosclerosis participants with mean age 58.1 ± 12.4 years, 48% men, free of overt CVD, having SBP and DBP less than 130/85 mmHg and not using any antihypertensive medication, and having plasma PIIINP and ICTP measurements, all assessed at baseline. We studied the association of baseline PIIINP and ICTP with the relative incidence density (RID) of incident hypertension, defined as SBP/DBP at least 140/90 mmHg, or antihypertensive therapy use during follow-up (four examinations over median 9.4 years).

RESULTS

Baseline mean SBP/DBP was 110.9 ± 14.0/67.9 ± 10.4 mmHg. Mean concentration of PIIINP was 5.39 ± 1.95 μg/l and ICTP was 3.18 ± 1.39 μg/l. During follow-up visits, 35.9% of the participants developed hypertension. After adjustment for age, race, and sex there was a significant RID for new onset of hypertension of 1.16 (1.06, 1.28), P = 0.0017 for PIIINP and 1.20 (1.08,1.33) for ICTP, P = 0.0008. After additional adjustment for renal function, CVD risk factors and inflammatory variables, RID for new onset hypertension was 1.28 (1.15,1.42), P < 0.001 for PIIINP and 1.29 (1.15,1.44) for ICTP, P < 0.0001.

CONCLUSION

Biomarkers of ECM remodeling predicted the development of hypertension in normotensive participants free of overt CVD.

Markers of Atherosclerosis: Part 1 - Serological Markers

Atherosclerosis is a major contributor to morbidity and mortality worldwide. With therapeutic consequences in mind, several risk scores are being used to differentiate individuals with low, intermediate or high cardiovascular (CV) event risk. The most appropriate management of intermediate risk individuals is still not known, therefore, novel biomarkers are being sought to help re-stratify them as low or high risk. This narrative review is presented in two parts. Here, in Part 1, we summarise current knowledge on serum (serological) biomarkers of atherosclerosis. Among novel biomarkers, high sensitivity C-reactive protein (hsCRP) has emerged as the most promising in chronic situations, others need further clinical studies. However, it seems that a combination of serum biomarkers offers more to risk stratification than either biomarker alone. In Part 2, we address genetic and imaging markers of atherosclerosis, as well as other developments relevant to risk prediction.

Markers of Atherosclerosis: Part 2 - Genetic and Imaging Markers

This is Part 2 of a two-part review summarising current knowledge on biomarkers of atherosclerosis. Part 1 addressed serological biomarkers. Here, in part 2 we address genetic and imaging markers, and other developments in predicting risk. Further improvements in risk stratification are expected with the addition of genetic risk scores. In addition to single nucleotide polymorphisms (SNPs), recent advances in epigenetics offer DNA methylation profiles, histone chemical modifications, and micro-RNAs as other promising indicators of atherosclerosis. Imaging biomarkers are better studied and already have a higher degree of clinical applicability in cardiovascular (CV) event prediction and detection of preclinical atherosclerosis. With new methodologies, such as proteomics and metabolomics, discoveries of new clinically applicable biomarkers are expected.

Collagen biomarkers and subclinical interstitial lung disease: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Lung fibrosis is attributed to derangements in extracellular matrix remodeling, a process driven by collagen turnover. We examined the association of two collagen biomarkers, carboxy-terminal telopeptide of collagen type I (ICTP) and amino-terminal propeptide of type III procollagen (PIIINP), with subclinical interstitial lung disease (ILD) in adults.

METHODS

We performed a cross-sectional analysis of 3244 participants age 45-84 years in the Multi-Ethnic Study of Atherosclerosis. Serum ICTP and PIIINP levels were measured at baseline by radioimmunoassay. Subclinical ILD was defined as high attenuation areas (HAA) in the lung fields on baseline cardiac CT scans. Interstitial lung abnormalities (ILA) were measured in 1082 full-lung CT scans at 9.5 years median follow-up. We used generalized linear models to examine the associations of collagen biomarkers with HAA and ILA.

RESULTS

Median (IQR) for ICTP was 3.2 μg/L (2.6-3.9 μg/L) and for PIIINP was 5.3 μg/L (4.5-6.2 μg/L). In fully adjusted models, each SD increment in ICTP was associated with a 1.3% increment in HAA (95% CI 0.2-2.4%, p = 0.02) and each SD increment in PIIINP was associated with a 0.96% increment in HAA (95% CI 0.06-1.9%, p = 0.04). There was no association between ICTP or PIIINP and ILA. There was no evidence of effect modification by gender, race, smoking status or eGFR.

CONCLUSIONS

Higher levels of collagen biomarkers are associated with greater HAA independent of gender, race and smoking status. This suggests that extracellular matrix remodeling may accompany subclinical ILD prior to the onset of clinically evident disease.

Predictive Value of Collagen Biomarkers for Heart Failure With and Without Preserved Ejection Fraction: MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND

Collagen biomarkers may correlate with incident heart failure (HF) and its subtypes. We hypothesized that circulating procollagen type III N-terminal propeptide (PIIINP) and collagen type I carboxy-terminal telopeptide (ICTP) predict incident HF.

METHODS AND RESULTS

We used a stratified sampling design in a multiethnic sample of 3187 subjects, initially aged 45 to 84 years and free of cardiovascular disease. We assayed baseline serum PIIINP and ICTP concentrations using radioimmunoassay. Incident HF was adjudicated, distinguishing reduced ejection fraction (HFrEF; EF <45%) from preserved EF (HFpEF; EF ≥45%). The incidence density for HFpEF and HFrEF was computed using Poisson regression per SD for each of PIIINP and ICTP, adjusting in model 1 for age, race, sex, and renal function or in model 2 for these variables plus blood pressure and medication. Mean (SD) ICTP was 3.38±1.77 μg/L, and mean (SD) PIIINP was 5.48±2.04 μg/L. Among the HF cases, 96 were HFrEF and 107 were HFpEF. Neither ICTP nor PIIINP significantly predicted incident HFrEF. The incidence density for HFpEF per 100 people observed for 13 years was 1.65 for low PIIINP (lower 6 octiles) versus 3.00 for higher PIIINP (P=0.002) in model 1 and correspondingly 1.45 versus 2.59 (P=0.003) in model 2. For low ICTP (lower 7 octiles) versus higher ICTP (octile 8), incidence densities were 1.79 versus 3.64 (P=0.002) in model 1 and 1.58 versus 3.12 (P=0.002) in model 2.

CONCLUSIONS

High levels of circulating ICTP and PIIINP as collagen biomarkers appear to be associated with incident HFpEF, but not HFrEF.