Association of serum proprotein convertase subtilisin/kexin type 9 with early atherosclerosis in newly diagnosed type 2 diabetes mellitus

Association between serum PCSK9 and coronary heart disease in patients with type 2 diabetes mellitus

BACKGROUND AND AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is considered a new biomarker for atherosclerosis, but its ability to predict cardiovascular outcomes has been controversial. This study aimed to address the lack of data on PCSK9, coronary heart disease (CHD) severity, and major cardiovascular events (MACEs) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 2984 T2DM patients underwent selective coronary angiography, and their serum PCSK9 levels were measured using enzyme-linked immunosorbent assay. Correlation and logistic regression analyses were performed to investigate the association between PCSK9 expression and CHD severity. This study used Cox regression analysis to assess the association between circulating PCSK9 levels and the risk of MACEs.

RESULTS

Circulating PCSK9 levels were significantly higher in the CHD group than in the non-CHD group [554.62 (265.11) ng/mL vs. 496.86 (129.05) ng/mL, p < 0.001]. Circulating PCSK9 levels positively correlated with CHD severity (diseased vessels: r = 0.35, p < 0.001; Gensini score: r = 0.46, p < 0.001). Elevated PCSK9 levels are an independent risk factor for CHD risk and severity (CHD group vs. non-CHD group: OR = 2.829, 95% CI: 1.771-4.520, p < 0.001; three vessel disease group vs. one vessel disease group: OR = 4.800, 95% CI: 2.387-9.652, p < 0.001; high GS group vs. low GS group: OR = 5.534, 95% CI: 2.733-11.208, p < 0.001). Through a six-year follow-up and multivariate Cox regression analysis, elevated circulating PCSK9 levels were found to be independently associated with MACEs in all participants (HR: 3.416, 5% CI: 2.485-4.697, p < 0.001; adjusted HR: 2.780, 95% CI: 1.930-4.004, p < 0.001).

CONCLUSIONS

Serum PCSK9 levels were positively correlated with multi-vessel CHD and Gensini score. Elevated circulating PCSK9 levels are an independent risk factor for CHD and increased incidence of MACEs in T2DM.

Serum proprotein convertase subtilisin/Kexin type 9 and vascular disease in type 2 diabetic patients

BACKGROUND

Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) levels have been suggested as novel atherosclerotic biomarker. PCSK9 plays important roles in the pathogenesis of atherosclerosis by regulating the degradation of low-density lipoprotein receptor as well as different inflammatory pathways. Considering the important prognostic role of arterial stiffness in cardiovascular disease (CVD), the aim of the study is to investigate the correlation between PCSK9 levels and arterial stiffness in a cohort of diabetic patients, without previous CV events.

METHODS

This cross-sectional analysis enrolled 401 Caucasian patients with type II diabetes mellitus (T2DM). PCSK9 levels were measured by ELISA test, arterial stiffness was estimated by measuring carotid-femoral pulse wave velocity (PWV).

RESULTS

Patients were divided in three tertiles according to increasing value of PCSK9. From the I to the III tertiles, there was a significant increase in high sensitivity C-reactive protein (hs-CRP), fibrinogen and white blood cells (WBC) and a reduction in estimated glomerular filtration rate (e-GFR). Patients with higher levels of PCSK9 presented increased systolic, diastolic blood pressure, pulse pressure and PWV. PWV was significantly and directly correlated with PCSK9, fibrinogen, age, BMI and PP, and indirectly correlated with diet, lifestyle and e-GFR. Serum PCSK9 was the major predictor of PWV, justifying a 16.9% of its variation.

CONCLUSION

Our study demonstrates a close association between circulating PCSK9 levels and PWV in T2DM subjects without previous CV events even after adjusting for well-known CV risk factor and pharmacological medications. Serum PCSK9 could be a useful biomarker for CV risk stratification in diabetic subjects.

Proprotein convertase subtilisin/kexin type 9 is associated with atherosclerosis in patients with Behcet's disease

OBJECTIVES

The incidence of cardiovascular disease is increased in patients with Behcet's disease (BD). Proprotein convertase subtilisin/kexin type 9 (PCSK9) causes the acceleration of atherosclerosis. We aimed to investigate whether there is a relationship between PCSK9 with carotid artery intima-media thickness (cIMT), a marker of subclinical atherosclerosis, and BD disease activity.

METHODS

Fifty-eight patients with BD and 58 age-, gender-, and body mass index (BMI)-matched healthy control subjects were included in the study. The disease activity of the patients was estimated. Individuals' cIMT values were measured, and PCSK9 levels were studied.

RESULTS

Patients with BD' cIMT (0.51 ± 0.1 vs 0.41 ± 0.1 mm, p < .001) and PCSK9 (623.2 ± 101.7 ± 10.1 vs 528.3 ± 242.7 ng/ml, p = .007), values were significantly higher than the control group. In stepwise regression analysis, there was an independent relationship between cIMT with PCSK9 (β = 0.179, p < .050). There was no independent relationship between disease activities with PCSK9. Based on the ROC curve analysis, the PCSK9 optimal cutoff value for cIMT was 595.1 ng/ml, sensitivity 66.7%, specificity 64.7% (AUC = 0.672; 95% CI: 0.530-0.815, p = .040).

CONCLUSION

There is a strong independent association between subclinical atherosclerosis and PCSK9 in patients with BD. There may be no independent association between PCSK9 and disease activity.

Prevalence and Risk Factors of Abnormal Carotid Artery in Young Adults without Overt Cardiovascular Disease

Objective

The current study was to evaluate the prevalence of increased carotid artery intimal-medial thickness (IMT) and carotid plaque in young individuals and factors associated with increased IMT and carotid plaque were also assessed.

Methods

Individuals between 18 and 44 years old who underwent an annual health examination and without cardiovascular disease were included. The value of IMT ≥0.1 cm was defined as increased IMT and IMT ≥0.15 cm was defined as carotid plaque. Based on the IMT, participants were divided into normal and abnormal groups.

Results

A total of 551 individuals were included and the mean age was 38.9 years old, with women accounting for 32.5% (n=179) and 238 (43.2%) individuals with abnormal IMT. Those with abnormal IMT was older, more likely to be male and smoking, had higher blood pressure (BP) and body mass index (BMI). Individuals with abnormal MIT also had worse lipid profiles, higher serum levels of fasting plasma glucose (FPG), HbA1c, homocysteine, and uric acid. Age, male sex, elevated systolic and diastolic BP, BMI, HbA1c, FPG, triglyceride, total cholesterol, LDL-C, homocysteine, and uric acid were positively correlated with IMT, while HDL-C was negatively correlated with IMT. Factors associated with increased IMT and carotid plaque included age, male sex, BMI, triglyceride, LDL-C, homocysteine, uric acid, and smoking.

Conclusion

Among apparent healthy young individuals, the prevalence of increased IMT was high and there were several factors associated with increased IMT. Further studies are needed to evaluate how to be better in preventing the development of subclinical atherosclerosis among young individuals.

Correlation Between Circulating PCSK9 Levels and Gestational Diabetes Mellitus in a Chinese Population

BACKGROUND

Previous studies reported that proprotein convertase subtilisin/kexin type 9 (PCSK9) was a key player in the regulations of lipid metabolism and glucose homeostasis. The current study aimed to detect the expression of PCSK9 in pregnant women with gestational diabetes mellitus (GDM) and investigate the possible relationships between PCSK9 and related metabolic phenotypes in GDM.

METHODS

Circulating PCSK9 levels were determined by ELISA kit in a cohort of subjects with GDM (n = 170) and normal glucose tolerance (NGT; n = 130). We collected blood samples from all participants for the biochemical index determinations. Diagnosis of GDM was made according to the International Association of the Diabetes and Pregnancy Study Groups Consensus Panel. Correlation analysis and logistic regression analysis were used to study the potential associations between PCSK9 and GDM.

RESULTS

GDM women presented significantly higher circulating PCSK9 levels than those in NGT pregnant subjects (268.07 ± 77.17 vs. 254.24 ± 74.22 ng/ml, P < 0.05). In the GDM group, serum PCSK9 levels were positively correlated with fasting plasma glucose (FPG) (R = 0.251, P = 0.015), glycated hemoglobin (HbA1c) (R = 0.275, P = 0.009), total cholesterol (TC) (R = 0.273, P = 0.010), and low-density lipoprotein cholesterol (LDL-C) (R = 0.326, P = 0.002) after adjustment of age and gestational age. Logistic regression found that age [odds ratio (OR) = 5.412, P = 0.02] and serum PCSK9 levels (OR = 4.696, P = 0.03) were independently associated with GDM. Compared with the lowest serum PCSK9 level quartile group, the prevalence of GDM was significantly higher in the highest quartile group, the ORs of GDM were 3.485 (95% CI 1.408-8.627, P < 0.05 for the trend), after adjusting for potential confounders.

CONCLUSIONS

Circulating PCSK9 levels were associated with dyslipidemia, pathoglycemia, and the risk of incident GDM, indicating a potential link between PCSK9 and GDM.

Dyslipidemia, Diabetes and Atherosclerosis: Role of Inflammation and ROS-Redox-Sensitive Factors

The prevalence of diabetes is growing at an alarming rate with increased disability, morbidity, and often premature mortality because of the various complications of this disorder. Chronic hyperglycemia, dyslipidemia, and other metabolic alterations lead to the development and progression of macro- and microvascular complications of diabetes including cardiovascular, retinal and kidney disease. Despite advances in glucose and lipid lowering treatments, a large number of diabetic individuals develop one or more types of these complications, ultimately leading to end-organ damage over the time. Atherosclerosis is the major macro-vascular complications of diabetes and the primary underlying cause of cardiovascular disease (CVD) posing heavy burden on the health care system. In this review, we discuss the involvement of dyslipidemia in the progression of atherosclerosis by activating the pro-inflammatory cytokines and oxidative stress-related factors. In addition, we also provide information on various pharmacological agents that provides protection against diabetic atherosclerosis by reducing inflammation and oxidative stress.

Relationship between Circulating PCSK9 and Markers of Subclinical Atherosclerosis-The IMPROVE Study

(1) Background and purpose: circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) is one of the key regulators of cholesterol metabolism. Despite this, its role as a player in atherosclerosis development is still matter of debate. Here, we investigated the relationships between this protein and several markers of subclinical atherosclerosis. (2) Methods: the IMPROVE study enrolled 3703 European subjects (54–79 years; 48% men; with ≥3 vascular risk factors), asymptomatic for cardiovascular diseases. PCSK9 levels were measured by ELISA. B-mode ultrasound was used to measure markers of carotid subclinical atherosclerosis. (3) Results: in the crude analysis, PCSK9 levels were associated with several baseline measures of carotid intima-media thickness (cIMT) (all p < 0.0001); with cIMT change over time (Fastest-IMTmax-progr) (p = 0.01); with inter-adventitia common carotid artery diameter (ICCAD) (p < 0.0001); and with the echolucency (Grey Scale Median; GSM) of both carotid plaque and plaque-free common carotid IMT (both p < 0.0001). However, after adjustment for age, sex, latitude, and pharmacological treatment, all the afore-mentioned correlations were no longer statistically significant. The lack of correlation was also observed after stratification for sex, latitude, and pharmacological treatments. (4) Conclusions: in subjects who are asymptomatic for cardiovascular diseases, PCSK9 plasma levels do not correlate with vascular damage and/or subclinical atherosclerosis of extracranial carotid arteries.

Association of circulating proprotein convertase subtilisin/kexin type 9 levels and the risk of incident type 2 diabetes in subjects with prediabetes: a population-based cohort study

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates cholesterol metabolism by targeting the low-density lipoprotein receptor. Recent studies have shown that circulating PCSK9 is associated with glucose homeostasis and insulin resistance. The aim of this study was to examine the association of circulating PCSK9 levels and risk for the development of type 2 diabetes in individuals with prediabetes.

METHODS

A population-based prospective study was conducted among 4205 Chinese subjects with prediabetes (average age 56.1 ± 7.5 years). Incident type 2 diabetes was diagnosed according to 2010 American Diabetes Association criteria. Circulating PCSK9 levels were measured using a commercially available enzyme-linked immunosorbent assay (ELISA). The association of circulating PCSK9 levels with the risk of incident type 2 diabetes was assessed by Cox regression analysis.

RESULTS

During a median follow-up period of 3.1 years, 568 subjects developed type 2 diabetes. Baseline circulating PCSK9 levels were significantly higher in female subjects developing incident type 2 diabetes than in those not developing incident type 2 diabetes (p < 0.001). In female subjects, the risk of incident type 2 diabetes was significantly higher in the highest PCSK9 quartile group (hazard ratio 2.16; 95% confidence interval 1.16-4.04) than in the lowest quartile group after adjustments for age, body mass index, waist circumference, C-reactive protein, γ-glutamyltransferase, triglycerides, low-density lipoprotein cholesterol, systolic blood pressure, and homeostatic model assessment of insulin resistance score. No significant association was observed between PCSK9 and incident type 2 diabetes in male subjects.

CONCLUSION

Elevated circulating PCSK9 levels are associated with an increased incidence of type 2 diabetes in female subjects with prediabetes.

Depression and cardiovascular risk-association among Beck Depression Inventory, PCSK9 levels and insulin resistance

BACKGROUND

Depression and cardiovascular disease (CVD) are among the most common causes of disability in high-income countries, depression being associated with a 30% increased risk of future CV events. Depression is twice as common in people with diabetes and is associated with a 60% rise in the incidence of type 2 diabetes, an independent CVD risk factor. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of low-density lipoprotein cholesterol, has been related to a large number of CV risk factors, including insulin resistance. Aim of this study was to investigate whether the presence of depression could affect PCSK9 levels in a population of obese subjects susceptible to depressive symptoms and how these changes may mediate a pre-diabetic risk.

RESULTS

In 389 obese individuals, the Beck Depression Inventory (BDI-II) was significantly associated with PCSK9 levels. For every one-unit increment in BDI-II score, PCSK9 rose by 1.85 ng/mL. Depression was associated also with the HOMA-IR (homeostatic model assessment index of insulin resistance), 11% of this effect operating indirectly via PCSK9.

CONCLUSIONS

This study indicates a possible mechanism linking depression and insulin resistance, a well-known CV risk factor, providing evidence for a significant role of PCSK9.

Combined intake of glucose-and lipid-lowering medications further elevates plasma levels of PCSK9 in type 2 diabetes patients

BACKGROUND AND AIM

This study examined the status of plasma levels of protein convertase subtilisin/kexin 9 (PCSK9) in association with glucose-and lipid-lowering medications in subjects with type 2 diabetes (T2D).

METHODS

This study comprised 177 diabetics and 115 non-diabetic subjects recruited from the United Arab Emirates National Diabetes Study (UAEDIAB). Clinical and biomedical data were collected by standard techniques. Plasma levels of PCSK9 were determined using ELISA.

RESULTS

PCSK9 levels were higher in diabetics than non-diabetics (P < 0.001). Diabetics with disease duration >5 years, HbA1c > 7.0%, or male subjects, had significantly higher levels of PCSK9 than their counterparts (P < 0.05). Regression analysis revealed that HbA1c and age are predictors for PCSK9 in T2D subjects. Diabetic subjects with abnormal lipids profile on lipid-lowering medications had a higher level of PCSK9 compared to those with normal lipids profile (85.6 ± 40.5 vs. 63.7 ± 39.5 ng/ml, respectively; P < 0.01). Diabetics on combined intake of insulin and oral glucose-lowering drugs had higher levels of PCSK9 than those not taking any (86.1 ± 41.6 vs 69.7 ± 36.1 ng/ml, respectively; P < 0.05). The highest levels of PCSK9 however, were in diabetics on combined lipid- and glucose-lowering therapy when compared to those, not on any (96.2 ± 34.0 vs 66.0 ± 35.1 ng/ml, respectively; P < 0.01).

CONCLUSIONS

Age and HbA1c are the most predictors for the elevated levels of PCSK9 in Emirati T2D subjects. Combined therapy of glucose-and lipid-lowering medications further elevates plasma levels of PCSK9 in diabetic subjects.

Differential effects of red yeast rice, Berberis aristata and Morus alba extracts on PCSK9 and LDL uptake

BACKGROUND AND AIMS

The novel nutraceutical combination containing red yeast rice (monacolin K 3.3 mg), Berberis aristata cortex extract (Berberine 531.25 mg) and Morus alba leaves extract (1-deoxynojirimycin 4 mg) is effective in the management of elevated plasma low-density lipoprotein cholesterol (LDL-C) levels. The aim of the present study was to investigate the effects of the three components on proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of LDL receptor (LDLR) expression, in hepatocyte cell lines and to compare their effects on LDL cellular uptake.

METHODS AND RESULTS

HepG2 and Huh7 cells were incubated with B. aristata cortex extract (BCE), red yeast rice (RYR) and M. alba leaves extract (MLE) alone or in combination for 24 h. RYR (50 μg/mL) increased PCSK9 protein expression (Western blot analysis and ELISA), PCSK9 mRNA (qPCR) and its promoter activity (luciferase reporter assay). BCE (40 μg/mL) reduced instead PCSK9 expression, mRNA levels and promoter activity. MLE determined a concentration-dependent reduction of PCSK9 at the mRNA and protein levels, with a maximal reduction at 1 mg/mL, without significant changes of PCSK9 promoter activity. MLE also downregulated the expression of 3-hydroxy-3-methyl-3-glutaryl coenzyme A reductase and fatty acid synthase mRNA levels. The combination of RYR, BCE and MLE reduced the PCSK9 mRNA and protein levels, as well as the promoter activity. Finally, the single components and their combination induced LDL receptor and LDL uptake by the hepatocytes.

CONCLUSION

The positive effect of MLE on PCSK9 supports the rationale of using the nutraceutical combination of RYR, BCE and MLE to control hyperlipidemic conditions.