Serum YKL-40 is increased in patients with slow coronary flow

Role of Chitinase-3-like Protein 1 in Cardioprotection and Angiogenesis by Post-Infarction Exercise Training

Chitinase-3-like protein 1 (CHI3L1) is a myokine involving tissue remodeling and inflammatory processes. CHI3L1 and its receptor protease-activated receptor 2 (PAR2) are induced by exercise in skeletal muscles. However, it remains unknown if CHI3L1/PAR2 signaling also mediates exercise-induced cardioprotection after myocardial infarction. Twenty-four adult male rats were divided into three groups (n = 8/group), receiving: (1) a sham operation; (2) permanent ligation of left anterior descending coronary artery; and (3) post-MI exercise training with one-week adaptive treadmill exercise for seven days followed by four weeks of aerobic exercise. Left ventricular systolic and end-diastolic pressure indices were measured and cardiac fibrosis, and angiogenesis were examined. Furthermore, HUVEC cells were treated in vitro with AMPK agonist—AICAR (a putative pharmacological memetic of exercise), recombinant human CHI3L1, PAR2 receptor blocker (AZ3451), and PI3K inhibitor (LY294002), respectively. We found that post-MI exercise significantly upregulated CHI3L1, PAR2, pPI3K/PI3K, pAKT/AKT, pERK/ERK, improved cardiac function, and diminished fibrosis. AICAR increased HUVEC tubules formation and upregulated CHI3L1 and PAR2 and these changes were attenuated by PAR2 blocker. In conclusion, post-MI exercise training can effectively activate CHI3L1/PAR2 signaling, which led to the improved myocardial function and enhanced cardiac angiogenesis in the infarcted heart.

YKL-40 as a novel biomarker in cardio-metabolic disorders and inflammatory diseases

Dyslipidaemia is associated with numerous health problems that include the combination of insulin resistance, hypertension and obesity, ie, metabolic syndrome. Although the use of statins to decrease serum low density lipoprotein cholesterol (LDL-C) has been an effective therapeutic in treating atherosclerosis, the persistence of high atherosclerotic risk, ie, residual risk, is notable and is not simply explained as a phenomenon of dyslipidaemia. As such, it is imperative that we identify new biomarkers to monitor treatment and more accurately predict future cardiovascular events. This athero-protective strategy includes the assessment of novel inflammatory biomarkers such as YKL-40. Recent evidence has implicated YKL-40 in patients with inflammatory diseases and cardio-metabolic disorders, making it potentially useful to evaluate disease severity, prognosis and survival. In this review, we summarize role of YKL-40 in the pathogenesis of cardio-metabolic disorders and explore its use as a novel biomarker for monitoring athero-protective therapy.

Prognosis and Reclassification by YKL-40 in Stable Coronary Artery Disease

Background

The inflammatory biomarker YKL‐40 has previously been studied as a potential risk marker in cardiovascular disease. We aimed to assess the prognostic reclassification potential of serum YKL‐40 in patients with stable coronary artery disease.

Methods and Results

The main study population was the placebo group of the CLARICOR (Effect of Clarithromycin on Mortality and Morbidity in Patients With Ischemic Heart Disease) trial. The primary outcome was a composite of acute myocardial infarction, unstable angina pectoris, cerebrovascular disease, and all‐cause mortality. We used Cox proportional hazards regression models adjusted for C‐reactive protein level and baseline cardiovascular risk factors. Improvement in prediction by adding serum YKL‐40 to the risk factors was calculated using the Cox‐Breslow method and c‐statistic. A total of 2200 patients were randomized to placebo, with a follow‐up duration of 10 years. YKL‐40 was associated with an increased risk of the composite outcome (hazard ratio per unit increase in (YKL‐40) 1.13, 95% CI 1.03–1.24, P=0.013) and all‐cause mortality (hazard ratio 1.32, 95% CI 1.17–1.49, P<0.0001). Considering whether a composite‐outcome event was more likely to have, or not have, occurred to date, we found 68.4% of such predictions to be correct when based on the standard predictors, and 68.5% when serum YKL‐40 was added as a predictor. Equivalent results were obtained with c‐statistics.

Conclusions

Higher serum YKL‐40 was independently associated with an increased risk of adverse cardiovascular outcomes and mortality. Addition of YKL‐40 did not improve risk prediction in patients with stable coronary artery disease.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00121550.

Association between increased serum alkaline phosphatase and the coronary slow flow phenomenon

BACKGROUND

Despite marked advances in our understanding of the pathophysiology of the coronary slow flow phenomenon (CSFP), the exact mechanism remains unclear. Previous studies have suggested that CSFP might be associated with generalized atherosclerosis, endothelial dysfunction, and low-grade chronic inflammation. High serum alkaline phosphatase (ALP) levels are associated with vascular calcification, atherosclerotic disease, and an increased risk of cardiovascular events. However, the relationship between ALP and CSFP is unclear.

METHODS

We investigated 64 patients with angiographically proven CSFP and 50 with normal coronary flow. Serum ALP levels were measured in all studied individuals.

RESULTS

Serum ALP levels in patients with CSFP were significantly higher than those in the control group (70.5 ± 17.1 vs. 61.9 ± 16.1 U/L, P = 0.007). A positive association was observed (r = 0.42, P = 0.032) between serum ALP levels and the mean thrombolysis in myocardial infarction frame count (mTFC). Regression analysis showed a high serum ALP level was the only independent predictor of the mTFC (β = 0.309, P < 0.001). Moreover, our study showed that a serum ALP level > 67.5 U/L was a predictor of CSFP (sensitivity = 83.3%, specificity = 84.1%).

CONCLUSIONS

Patients with CSFP show high serum ALP levels, which may be associated with the pathogenesis of CSFP. A high serum ALP level is a predictor of CSFP. Future studies are needed to clarify the role of ALP in patients with CSFP.

A novel marker of inflammation in patients with slow coronary flow: lymphocyte-to-monocyte ratio

AIM

Recently, lymphocyte-to-monocyte ratio (LMR) has emerged as a new indirect marker of inflammation which is associated with adverse outcomes in oncology and cardiovascular diseases. The aim of the study was to evaluate the relationship between LMR and slow coronary flow (SCF).

PATIENTS & METHODS

A total of 100 consecutive patients with SCF and 100 consecutive patients with normal coronary flow were enrolled in this study.

RESULTS

LMR was significantly lower in patients with SCF than in patients with normal coronary flow (p < 0.001). Also, LMR was negatively correlated with neutrophil-to-lymphocyte ratio and CRP levels (p < 0.001 and p = 0.005). LMR was found to be significantly and independently associated with SCF (p = 0.033).

CONCLUSION

LMR was negatively correlated with serum C-reactive protein and neutrophil-to-lymphocyte ratio levels.

The relationship between eosinophilia and slow coronary flow

Aim

The pathophysiology of slow coronary flow (SCF) involves atherosclerosis, small vessel dysfunction, platelet function disorders, and inflammation. It has been known that eosinophils also play a significant role in inflammation, vasoconstriction, thrombosis, and endothelial dysfunction. We propose to evaluate the relationship between eosinophilia and SCF.

Methods

All patients who underwent coronary angiography between January 2011 and December 2013 were screened retrospectively. Of 6,832 patients, 102 patients with SCF (66 males, mean age 52.2±11.7 years) and 77 control subjects with normal coronary angiography (50 males, mean age 50.7±8.1 years) were detected. Baseline characteristics, hematological test results, and biochemical test results were obtained from the hospital database.

Results

Baseline characteristics of the study groups were comparable between groups. There was no significant difference between groups regarding leukocyte count, paletelet count, and mean platelet volume. However, patients with SCF had a higher eosinophil count than the controls (0.24±0.17×10³/μL vs 0.16±0.15×10³/μL, P=0.002). In addition, eosinophil count was found to be correlated with thrombolysis in myocardial infarction (TIMI) frame count in the SCF group (r=0.3, P<0.01). There was no significant correlation between eosinophil count and the number of coronary arteries showing slow flow.

Conclusion

Patients with SCF have higher blood eosinophil count, and this may play an important role in the pathogenesis of SCF. Elevated baseline eosinophil count may indicate the presence of SCF.

Association of Monocyte-to-HDL Cholesterol Ratio with Slow Coronary Flow is Linked to Systemic Inflammation

BACKGROUND

Previous studies proposed that both inflammation, oxidative stress, and impaired endothelial dysfunction have a significant role in occurrence of slow coronary flow (SCF). monocyte-to-high density lipoprotein cholesterol ratio (MHR) is a recently emerged indicator of inflammation and oxidative stress, which have been studied only in patients with chronic kidney disease.

HYPOTHESIS

We aimed to assess the relationship between MHR and SCF.

METHODS

Patients who had angiographically normal coronary arteries were enrolled in this retrospective study (n = 253 as SCF group and n = 176 as control group). Patients who had corrected thrombolysis in myocardial infarction frame counts (cTFCs) above the normal cutoffs were defined as with SCF.

RESULTS

The MHR and high-sensitivity C-reactive protein (hsCRP) were significantly higher in the SCF group. In correlation analysis, MHR has a significantly positive correlation with cTFC and serum hsCRP levels (P < .001). In multivariate logistic regression analysis, MHR was found as independently associated with the presence of SCF (odds ratio: 1.24, P < .001).

CONCLUSION

Higher MHR which indicates an enhanced inflammation and oxidative stress was significantly and independently associated with the presence of SCF. Besides, MHR was positively correlated with serum hsCRP level as a conventional marker for systemic inflammation.

Increased Platelet to Lymphocyte Ratio is Related to Slow Coronary Flow

Previous studies showed that both inflammation and platelets have a role in development of slow coronary flow (SCF). Platelet to lymphocyte ratio (PLR) as an emerging inflammatory indicator was significantly associated with adverse cardiovascular events. Therefore, we aimed to assess the relationship between PLR and SCF. Patients who had angiographically normal coronary arteries were enrolled in this retrospective study (n = 221 as SCF group and n = 293 as control group). Patients who had thrombolysis in myocardial infarction frame counts (TFC) above the normal cutoffs were considered to have SCF. Both PLR and C-reactive protein (CRP) were significantly higher in the SCF group. In correlation analysis, PLR has a significantly positive correlation with the left anterior descending artery TFC (P = .001), circumflex artery TFC (P < .001), right coronary artery TFC (P < .001), and serum CRP level (P < .001). In multiple logistic regression analysis, PLR was independently associated with presence of SCF (odds ratio: 1.014, P < .001). In conclusion, higher PLR levels were significantly and independently related to the presence of SCF. Besides, PLR was positively correlated with serum CRP level as a conventional marker for systemic inflammation.