Circulating levels of a biomarker of collagen metabolism are associated with health-related quality of life in patients with chronic heart failure.

PURPOSE: Assessment of circulating levels of collagen-derived peptides has been proposed as a useful tool to monitor indirectly myocardial collagen metabolism in chronic heart failure (CHF) patients. The potential link between circulating concentrations of collagen metabolism biomarkers and health-related quality of life (HRQOL) has not been adequately evaluated. With the present study, we investigated the association between serum levels of collagen-derived peptides and HRQOL. METHODS: We studied 280 consecutive outpatients (of mean age 67 ± 10 years, 180 men) with CHF. Serum concentrations of carboxy-terminal telopeptide of collagen type I (CITP)-a marker of collagen type I degradation-were measured in all patients both at baseline and during a period of 6 months follow-up. HRQOL was assessed by Minnesota living with heart failure questionnaire (MLHFQ). RESULTS: CITP levels were significantly associated with MLHFQ scores both at baseline (r = 0.231, P < 0.001) and at 6 months follow-up (r = 0.145, P = 0.044). CITP levels remained significantly associated with MLHFQ score in multivariable linear regression analysis. Higher CITP levels were observed with higher MLHFQ scores (poor HRQOL) both at baseline (P = 0.001) and at 6 months (P = 0.041). Unadjusted analysis demonstrated a significant relationship between increasing CITP levels during 6 months follow-up and worsening HRQOL (r = 0.204, P = 0.001). The aforementioned correlation remained significant in multivariable linear regression analysis. CONCLUSION: Our findings show that increased CITP levels are associated with poorer HRQOL in patients with CHF. These findings are consistent with a link between a pathophysiologic mechanism, i.e., collagen metabolism and patient self-assessed health status in CHF.

Interleukin-8 is increased in the membrane of circulating erythrocytes in patients with acute coronary syndrome.

AIMS: Studies have shown that erythrocyte membranes are present within necrotic cores in atherosclerotic plaques, and that circulating erythrocytes in patients with acute coronary syndrome (ACS) have increased total cholesterol content (CEM). Interleukin-8 (IL-8) binds to erythrocytes and during intraplaque haemorrhage it is released into the plaque and thus may contribute to inflammatory cascade and atherosclerotic plaque instability. The present study was undertaken to test the hypothesis that erythrocyte membrane IL-8 is elevated in patients with ACS compared with those with chronic stable angina (CSA). METHODS AND RESULTS: Consecutive patients who presented with CSA (n = 120, 92 men, 62 +/- 9 years), ACS (n = 118, 90 men, 62 +/- 10 years) or with chest pain who had normal coronary arteries (n = 36, 26 men, 60 +/- 7 years), were studied prospectively. IL-8 concentrations in erythrocyte membranes (rIL-8) and in plasma (pIL-8), C-reactive protein (CRP) and CEM were measured. rIL-8 levels [mean +/- 1 SD (standard deviation)] were higher in ACS (102.9 +/- 70.1 pg/mL) compared with CSA (44.7 +/- 22.8 pg/mL) (P < 0.001). No difference in pIL-8 levels between the two coronary artery disease groups was observed (P = 0.280). Serum CRP levels were correlated with rIL-8 levels (r = 0.294, P < 0.001); no association was found between CRP and pIL-8 levels (r = 0.025, P = 0.706). Further, rIL-8 had an independent association with ACS, when CRP and CEM were taken into consideration. CONCLUSION: This study shows for the first time that rIL-8 content was significantly higher in ACS, compared with CSA. These findings endorse results from our previous studies suggesting that erythrocytes may play an important role in the development of unstable atherosclerotic plaque.

Resolution of symptoms and serum peptides of collagen type I turnover in acute heart failure patients.

OBJECTIVES: Myocardial collagen content as a fundamental component of extracellular matrix, is altered in pathological states including heart failure (HF). Serum peptides related to myocardial collagen synthesis and degregation can be measured and may be used as indices of myocardial collagen turnover. The present study was undertaken to assess the hypothesis that resolution of acute decompensation of chronic HF is associated with changes in serum peptides related to collagen synthesis and degregation. METHODS AND RESULTS: Serum concentrations of the amino-terminal propetide of procollagen type I (PINP) and the carboxy-terminal telopeptide of collagen type I (CITP), indices of collagen type I synthesis and degradation, respectively, were determined at the time of admission and discharge in 156 patients (100 men, 68 +/- 10 years) with acute decompensation of chronic HF. A significant decrease (-3.5 ng/ml 95% CI -5.3/-1.6 ng/ml, P < 0.001) of PINP was observed whereas CITP levels were significantly increased (+ 0.04 ng/ml 95% CI 0.01-0.08 ng/ml, P = 0.031) at discharge compared to admission. CONCLUSIONS: Findings of the present study showed that serum indices of myocardial collagen turnover were changed significantly in a short period of time during the improvement of acute decompensation of chronic HF.

Effect of statins on collagen type I degradation in patients with coronary artery disease and atrial fibrillation.

The present study was undertaken to assess the effect of statins on collagen type I degradation and C-reactive protein in patients with coronary artery disease and atrial fibrillation. One hundred six patients with coronary artery disease and atrial fibrillation were studied: 40 (36 men, mean age 72 +/- 8 years) treated with a statin and 66 (48 men, mean age 74 +/- 9 years) not treated with a statin. Serum concentrations of carboxy-terminal telopeptide of collagen type I, an index of collagen type I degradation, and high-sensitivity C-reactive protein were measured in all patients. Carboxy-terminal telopeptide of collagen type I levels were significantly higher (p <0.001) in statin-treated patients (0.64 ng/ml, 95% confidence interval [CI] 0.57 to 0.71) compared with nonstatin-treated patients (0.38 ng/ml, 95% CI 0.31 to 0.44). These changes were independent of cholesterol levels (before or after therapy). Statin-treated patients had significantly lower (p <0.001) C-reactive protein levels (0.25 mg/dl, 95% CI 0.23 to 0.28) compared to statin nonusers (1.1 mg/dl, 95% CI 0.92 to 1.25). In conclusion, this study suggests that therapy with statins in patients with coronary artery disease and atrial fibrillation is associated with an increase in collagen degradation and an attenuation of inflammation, independently of cholesterol lowering.

Serum levels of collagen type-I degradation markers are associated with vascular stiffness in chronic heart failure patients.

BACKGROUND: Chronic heart failure (CHF) induces peripheral vasoconstriction, endothelial dysfunction and arterial stiffness by activation of various neurohormonal pathways. The abnormal collagen turnover observed in CHF may be attributed not only to myocardial remodelling, but also to vascular remodelling. However, the effect of collagen metabolism on progressive large artery stiffening in the setting of CHF is understudied. AIMS: The present study was undertaken to investigate the association between circulating markers of collagen turnover and vascular stiffness in patients with CHF. METHODS: Eighty patients (mean age 65+/-11 years, 68 men) with stable CHF and in sinus rhythm, were studied. Serum concentrations of carboxy-terminal telopeptide of collagen type I (CITP) and amino-terminal propetide of procollagen type I (PINP), markers of collagen type I degregation and synthesis respectively, were measured in all patients. Pulse wave velocity (PWV) and augmentation index (AIx) of aortic pulse wave form, markers of arterial stiffness, were also determined by applanation tonometry. RESULTS: Peripheral PWV was inversely associated with serum CITP levels (r=-0.585, p<0.001). AIx although weakly was negatively correlated with serum CITP levels (r=-0.285, p=0.01). Multiple regression analysis showed that peripheral PWV remained independently associated with serum CITP levels after adjustment for all confounding variables. CONCLUSIONS: Findings from the present study imply a possible link between altered collagen metabolism and peripheral vascular stiffness in CHF.

Independent and additive prognostic ability of serum carboxy-terminal telopeptide of collagen type-I in heart failure patients: a multi-marker approach with high-negative predictive value to rule out long-term adverse events.

BACKGROUND: Altered myocardial extracellular matrix turnover has been proposed as a major determinant of myocardial remodelling. Carboxy-terminal telopeptide of collagen type-I (CITP) represents a collagen type-I degradation-derived serum peptide. In this study we examined the independent and additive prognostic value of serum concentrations of CITP compared with well-known mortality predictors such as the N-terminal pro-brain natriuretic peptide (NT-proBNP) in chronic heart failure (CHF) patients. METHODS: We studied 196 consecutive patients (126 male, mean age 69 ± 10 years), who were admitted for acute decompensation of the CHF syndrome. The study entry point was determined at the discharge of the patients after achieving a stable compensated status. The primary endpoint was cardiac mortality during a 12-month follow-up. RESULTS: In the multivariate Cox proportional hazard model the levels of CITP remained a predictor of survival (hazards ratio 0.4 95% confidence interval 0.21-0.76, P = 0.005), independent of NT-proBNP levels. The stratified log-rank test (P < 0.001) showed that CHF patients characterized by low levels of both biomarkers had better survival (hazards ratio 0.12 95% confidence interval 0.04-0.35, P < 0.001) compared with patients characterized by high levels of both biomarkers. The negative predictive value of the combined measure for long-term adverse events was 94%. CONCLUSION: Serum levels of CITP were shown to be an independent and strong prognostic marker regarding survival in CHF patients. Furthermore, CITP levels had an additive prognostic value compared with NT-proBNP levels. These findings underline the detrimental role of myocardial fibrosis in the progression of heart failure and suggest a novel multi-marker approach for risk stratification in the CHF syndrome.

Chronic heart failure patients with high collagen type I degradation marker levels benefit more with ACE-inhibitor therapy.

Not all patients respond to angiotensin converting enzyme (ACE)-inhibitor equally. Genetic or other phenotypic variations might be useful in predicting the therapeutic efficacy of these drugs. With the present study we assessed the prognostic impact of ACE-inhibitor in chronic heart failure patients with different degrees of collagen metabolism as assessed by serum levels of a collagen type I degradation marker (CITP). One hundred ninety-six (126 male, 69+/-10 years) chronic heart failure patients were studied prospectively for 12 months regarding survival. Serum concentrations of CITP were measured at study entry. Chronic heart failure patients were divided into groups according to whether (n=114) or not (n=82) they received ACE-inhibitor as well as to their CITP levels. Survival (52.2%) was significantly lower in ACE-inhibitor naive patients with high CITP levels compared to ACE-inhibitor naive patients with low CITP levels (83.3%, P=0.003), to ACE-inhibitor users with low CITP levels (80%, P=0.006) and to ACE-inhibitor users with high CITP levels (70.4%, P=0.015). ACE-inhibitor related improvement in mortality was most predominant in chronic heart failure patients with high CITP levels. CITP levels possibly reflecting an activated status of the renin-angiotensin-aldosterone system, may be of clinical relevance since they identify a subgroup of patients that is more susceptible to treatment with an ACE-inhibitor.

Cholesterol composition of erythrocyte membranes and its association with clinical presentation of coronary artery disease.

OBJECTIVES: Presence of free cholesterol in atherosclerotic plaques is a major determinant of plaque instability. It is hypothesized that extravasated erythrocytes may contribute to free cholesterol accumulation in atherosclerotic plaques through their rich in cholesterol membrane. In this study we assessed whether cholesterol in erythrocyte membranes (CEMs), that is, free (FCEM) versus esterified (ECEM), differs in patients with chronic stable angina (CSA) compared with patients presenting with acute coronary syndromes (ACSs). METHODS: Consecutive angina patients were prospectively assessed; 154 had CSA (118 men, 63 years, 56-69 years) and 164 ACS (124 men, 63 years, 55-71 years). FCEM and ECEM were measured using an enzymatic assay, and protein content was assessed by the Bradford method. RESULTS: FCEM was significantly higher (P<0.001) in the ACS patients group (94.1 microg/mg, IQ 71-116.5 microg/mg) compared with patients with CSA (61.9 microg/mg, IQ 49.3-73.1 microg/mg). ECEM levels were also significantly higher (P<0.001) in ACS patients (23.3 microg/mg, IQ 14.9-47.7 microg/mg) compared with CSA patients (10.8 microg/mg, IQ 8-22.3 microg/mg). In contrast, ratio of free-to-esterified cholesterol (P=0.110) as well as ratio of free-to-total CEM (P=0.109) were not different among CSA and ACS patients. CONCLUSION: Findings of this study show that although free cholesterol is the prevailing form of CEMs, both FCEM and ECEM levels are increased in patients with ACS compared with CSA patients. These findings suggest that it is the quantity of CEM rather than the type of cholesterol present in the erythrocyte membrane that determines plaque progression.

Circulating levels of collagen type I degradation marker depend on the type of atrial fibrillation.

AIMS: To investigate the hypothesis that circulating levels of collagen type I degradation or synthesis markers are associated with the presence and pattern of atrial fibrillation (AF). METHODS AND RESULTS: We assessed the serum concentrations of amino-terminal propeptide of procollagen type I (PINP) and of carboxy-terminal telopeptide of collagen type I (CITP), indexes of collagen type I synthesis and degradation, respectively, in 98 paroxysmal AF (PAF) patients (65 +/- 14 years, 62 men), in 80 persistent AF (PsAF) patients (73 +/- 8 years, 32 men), in 114 permanent AF (PmAF) patients (73 +/- 10 years, 54 men), and in 180 patients in sinus rhythm (SR) (66 +/- 13 years, 88 men) who represented a control group. Serum CITP levels were higher (P < 0.001) in AF patients [0.41 ng/mL, 95% confidence interval (CI) 0.38-0.44] when compared with SR patients (0.29 ng/mL, 95% CI 0.26-0.33) and were significantly different between the three AF pattern groups (P < 0.001). Patients with PAF (0.31 ng/mL, 95% CI 0.26-0.36) had lower CITP levels when compared with patients with PsAF (0.41 ng/mL, 95% CI 0.34-0.47) (P = 0.006), as well as with PmAF patients (0.49 ng/mL 95% CI, 0.43-0.56) (P < 0.001). Levels of CITP tended to be lower (P = 0.219) in PsAF patients when compared with sustained AF patients. No differences were found in PINP levels between AF and SR study groups (P = 0.637) as well as between the three AF pattern groups (P = 0.301). CONCLUSION: In the clinical setting, circulating levels of collagen type I degradation marker are associated with both type and duration of AF. Further studies are needed to evaluate the clinical use of serum concentrations of CITP as a potential diagnostic, prognostic, and therapeutic target in patients with AF.

Effect of angiotensin-converting enzyme insertion/deletion genotype on collagen type I synthesis and degradation in patients with atrial fibrillation and arterial hypertension.

OBJECTIVE: The present study was undertaken to assess the impact of the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphisms on circulating markers of collagen type I synthesis and degradation, and also to study the effect of therapy with ACE inhibitors on these markers in hypertensive patients with atrial fibrillation (AF). RESEARCH DESIGN AND METHODS: ACE I/D genotypes were assessed in 158 hypertensive patients (71 +/- 9 years; 72 male) with AF and 174 patients with arterial hypertension in sinus rhythm (SR) (71 +/- 9 years; 88 male). Serum concentrations of amino-terminal propeptide of pro-collagen type I (PINP) and of carboxy-terminal telopeptide of collagen type I (CITP), indices of collagen type I synthesis and degradation, respectively, were measured. RESULTS: Of the 332 study participants, 74 (22.3%) were I/I, 158 (47.6%) were I/D and 100 (30.1%) were D/D carriers. Genetic variation in ACE significantly influenced serum CITP levels in AF patients (p = 0.011). CITP levels were lower in D allele carriers (DD and ID) compared with I/I carriers. There was no difference in PINP levels between the different ACE genotype groups (p = 0.302). Patients treated with ACE inhibitors had higher CITP levels compared with those not treated (p = 0.036). CONCLUSIONS: This study suggests that the presence of the D allele in hypertensive patients with AF is associated with attenuation of type-I collagen degradation, and that therapy with ACE inhibitors increases degradation of collagen type I. The data indicate a subgroup of patients with AF and arterial hypertension who may benefit to a greater extent from therapy with ACE inhibitors, thus, providing a basis for pharmacogenetics.