Positive association of serum levels of pigment epithelium-derived factor with high-sensitivity C-reactive protein in apparently healthy unmedicated subjects

Pigment Epithelium-Derived Factor Declines in Response to an Oral Glucose Load and Is Correlated with Vitamin D and BMI but Not Diabetes Status in Children and Young Adults

BACKGROUND

Pigment epithelium-derived factor (PEDF) is associated with obesity and diabetes complications in adults, yet little is known about PEDF in younger individuals. We investigated the relationship between PEDF and various metabolic biomarkers in young healthy volunteers (HV) and similar-aged patients with diabetes (type 1 and type 2).

METHODS

A fasting blood sample was collected in 48 HV, 11 patients with type 1 diabetes (T1D), and 11 patients with type 2 diabetes (T2D) 12-25 years of age. In 9 healthy subjects, PEDF was also serially measured during a frequently sampled oral glucose tolerance test (OGTT).

RESULTS

PEDF was positively correlated with BMI and systolic blood pressure and negatively correlated with vitamin D. Upon multivariable analysis, BMI and vitamin D were independent predictors of PEDF. Prior to adjustment, PEDF was highest in T2D patients (7,168.9 ± 4417.4 ng/mL) and lowest in individuals with T1D (2,967.7 ± 947.1 ng/mL) but did not differ by diagnosis when adjusted for BMI and vitamin D. Among volunteers who underwent an OGTT, PEDF declined by ∼20% in response to an oral glucose load.

CONCLUSION

PEDF was acutely regulated by a glucose load and was correlated with BMI but not with diabetes. The negative correlation with vitamin D, independent of BMI, raises the question whether PEDF plays a compensatory role in bone matrix mineralization.

Metabolic syndrome in pediatrics

The ever growing prevalence of childhood obesity is being accompanied by an increase in the pediatric population of diseases once believed to be exclusive of the adulthood such as the metabolic syndrome (MS). The MS has been defined as the link between insulin resistance, hypertension, dyslipidemia, impaired glucose tolerance, and other metabolic abnormalities associated with an increased risk of atherosclerotic cardiovascular diseases in adults. In this review, we will discuss the peculiar aspects of the pediatric MS and the role of novel molecules and biomarkers in its pathogenesis.

Association of serum pigment epithelium-derived factor with high-sensitivity C-reactive protein in women with polycystic ovary syndrome

BACKGROUND

The basic studies showed that Pigment epithelium-derived factor (PEDF) plays an important role in inflammation.

AIM

This study aims to investigate the association of serum PEDF with high-sensitivity C-reactive protein (hs-CRP) in women with polycystic ovary syndrome (PCOS).

METHODS

Ninety-six PCOS women and 63 healthy, age-matched controls were enrolled in this study. Serum levels of PEDF, hs-CRP, Complement C3 (C3), glucose, insulin, lipids, and total testosterone were measured. Ninety-six PCOS women and 20 controls underwent hyperinsulinemiceuglycemic clamp to assess their insulin sensitivity, which was expressed as M value.

RESULTS

Serum PEDF levels and hs- CRP levels were much higher in PCOS women than in controls. In PCOS women, PEDF positively correlated with body mass index (BMI), hs-CRP, C3, LDL cholesterol (LDL-c), and systolic blood pressure (SBP), and negatively correlated with M value and HDL cholesterol (HDL-c). After controlling for BMI, PEDF was still positively correlated with hs-CRP. Multiple linear regression analysis revealed that in PCOS women, hs-CRP, SBP, LDL-c and M value were independent determinants of serum PEDF.

CONCLUSION

The serum PEDF levels are closely associated with hs-CRP in women with PCOS. PEDF may play a role in the development of chronic inflammation in PCOS.

Associations between pigment epithelium-derived factor, insulin resistance and high density lipoprotein

AIMS

To measure serum pigment epithelium-derived factor in control subjects with normal fasting glucose, and in subjects with impaired fasting glucose and those with newly diagnosed Type 2 diabetes, before treatment initiation, and to measure pigment epithelium-derived factor prospectively in patients being treated with HDL-raising therapy, niacin.

METHODS

We enrolled 89 individuals attending an institutional health screen. Biochemical indices including lipids, homeostasis model assessment-insulin resistance, high-sensitivity C-reactive protein and pigment epithelium-derived factor were analysed in fasting blood. To validate the association between HDL and pigment epithelium-derived factor, we analysed samples from a separate study cohort with low HDL, followed up for 12-weeks while on niacin treatment. Secreted pigment epithelium-derived factor from 3T3-L1 adipocytes, after HDL treatment (24-h), was measured using Western blot analysis.

RESULTS

Mean (± sd) serum pigment epithelium-derived factor was significantly higher in subjects with impaired fasting glucose [13.99 (± 3.06) μg/ml] and Type 2 diabetes [12.94 (± 2.61)] μg/ml, compared with control subjects [11.83 (± 2.85) μg/ml (P = 0.014)]. In multivariate analyses, serum pigment epithelium-derived factor concentration was associated with BMI (β = 0.32, 0.007), homeostasis model assessment-insulin resistance (β = 0.33, P = 0.01) and HDL (β = -0.24, P = 0.05), after adjustment for age, gender and high-sensitivity C-reactive protein. In the niacin study, on-treatment HDL was an independent determinant of pigment epithelium-derived factor (β = -0.439, P = 0.033), after adjusting for age, homeostasis model assessment-insulin resistance and treatment. Adipocytes treated with HDL were found to have reduced pigment epithelium-derived factor secretion [24.8% (50 μg/ml), 28.4% (100 μg/ml) HDL; P < 0.05)], compared with the control samples.

CONCLUSION

Serum pigment epithelium-derived factor is positively associated with homeostasis model assessment-insulin resistance and negatively associated with HDL. Further studies are needed to understand the mechanism of low HDL and raised pigment epithelium-derived factor and to determine if they are causally related to the pathobiology of insulin resistance.

Proteomic analysis of synovial fluid from the osteoarthritic knee: comparison with transcriptome analyses of joint tissues

OBJECTIVE

The pathophysiology of the most common joint disease, osteoarthritis (OA), remains poorly understood. Since synovial fluid (SF) bathes joint cartilage and synovium, we reasoned that a comparative analysis of its protein constituents in health and OA could identify pathways involved in joint damage. We undertook this study to perform a proteomic analysis of knee SF from OA patients and control subjects and to compare the results to microarray expression data from cartilage and synovium.

METHODS

Age-matched knee SF samples from 10 control subjects, 10 patients with early-stage OA, and 10 patients with late-stage OA were compared using 2-dimensional difference-in-gel electrophoresis and mass spectrometry (MS). MS with a multiplexed peptide selected reaction monitoring assay was used to confirm differential expression of a subset of proteins in an independent OA patient cohort. Proteomic results were analyzed by Ingenuity Pathways Analysis and compared to published synovial tissue and cartilage messenger RNA profiles.

RESULTS

Sixty-six proteins were differentially present in healthy and OA SF. Three major pathways were identified among these proteins: the acute-phase response signaling pathway, the complement pathway, and the coagulation pathway. Differential expression of 5 proteins was confirmed by selected reaction monitoring assay. A focused analysis of transcripts corresponding to the differentially present proteins indicated that both synovial and cartilage tissues may contribute to the OA SF proteome.

CONCLUSION

Proteins involved in the acute-phase response signaling pathway, the complement pathway, and the coagulation pathway are differentially regulated in SF from OA patients, suggesting that they contribute to joint damage. Validation of these pathways and their utility as biomarkers or therapeutic targets in OA is warranted.

Metabolic syndrome in youth: current insights and novel serum biomarkers

Paralleling the worldwide epidemic in childhood obesity, in the last decade we have observed a rise in the prevalence of metabolic syndrome (MetS) in pediatrics. The MetS comprises a cluster of cardiovascular risk factors. Multiple definitions have been proposed for the syndrome in the pediatric age group, but they are very difficult to test and validate. Thus, in this paper we will discuss the current knowledge in pediatric MetS and the potential role of novel biomarkers in the pathogenesis and diagnosis of MetS.

Serum pigment epithelium-derived factor levels are independently correlated with the presence of coronary artery disease

Background

Pigment epithelium-derived factor (PEDF) has been proved to be closely correlated with metabolic syndrome (MetS) and its components that are all risk factors of cardiovascular disease and may play a protective role against vascular injury and atherosclerosis. The present study was designed to investigate the relationship between serum PEDF and coronary artery disease (CAD).

Methods

A total of 312 consecutive in-patients (including 228 with CAD and 197 with MetS) who underwent coronary angiography were enrolled. Serum PEDF was measured by sandwich enzyme immunoassay and used to carry out multivariate stepwise regression analysis to assess correlation with patient demographic and clinical parameters. Multiple logistic regression analysis was performed to identify factors independently correlated with CAD.

Results

Patients with MetS had significantly higher levels of serum PEDF than non-MetS subjects (11.1(8.2, 14.2) vs. 10.1(7.6, 12.4) μg/mL; P < 0.05). Patients with CAD also had significantly higher serum PEDF than non-CAD subjects (11.0(8.1, 14.2) vs. 10.3(8.1, 12.8) μg/mL; P < 0.05). Triglyceride (TG), C-reactive protein (CRP), estimated glomerular filtration rate (eGFR), and hypoglycemic therapy were independently correlated with serum PEDF levels, and serum PEDF was independently positively correlated with CAD.

Conclusions

Serum PEDF levels are independently positively associated with CAD in a Chinese population. Elevated PEDF may act as a protective response against vascular damage and subsequent CAD.

Serum levels of pigment epithelium-derived factor (PEDF) are independently associated with procollagen III N-terminal peptide levels in patients with nonalcoholic fatty liver disease

OBJECTIVES

Pigment epithelium-derived factor (PEDF) is a glycoprotein that belongs to the superfamily of serine protease inhibitors with complex anti-oxidative, anti-fibrotic, and anti-inflammatory properties, thus being involved in cardiometabolic disorders. Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of the metabolic syndrome as well. However, the pathophysiological role of PEDF in NAFLD remains largely unknown. We studied here the relationship between serum PEDF levels and various clinical markers of NAFLD in humans.

DESIGN AND METHODS

The study involved 194 biopsy-proven NAFLD patients (102 male and 92 female) with a mean age of 51.3±13.8 years. We examined which anthropometric, metabolic and inflammatory variables, and liver steatosis and fibrosis markers are independently associated with serum levels of PEDF.

RESULTS

Mean serum levels of PEDF were 16.4±5.7 μg/mL. Univariate analysis revealed that age (inversely), male, body mass index, waist circumference, numbers of white blood cells and platelets, aspartate aminotransferase, alanine aminotransferase, fasting plasma glucose, glycated hemoglobin, uric acid, procollagen type III N-terminal peptide (P-III-P), subcutaneous fat areas, visceral fat areas and liver to spleen density ratio in computed tomography, the presence of diabetes and medication for hyperlipidemia were significantly associated with serum levels of PEDF. In multiple stepwise regression analysis, age (p<0.01, inversely), male (p<0.05), waist circumference (p<0.01), white blood cell number (p<0.05), P-III-P (p<0.05), and the presence of diabetes (p<0.05) and medication for hyperlipidemia (p<0.01), were independently correlated to serum levels of PEDF (R(2)=0.285).

CONCLUSIONS

The present study reveals that serum levels of PEDF are independently associated with P-III-P levels, suggesting that PEDF level is a novel biomarker of liver fibrosis in patients with NAFLD.

Serum level of pigment epithelium-derived factor is a marker of atherosclerosis in humans

OBJECTIVE

Pigment epithelium-derived factor (PEDF) could play a protective role against atherosclerosis. However, there is no clinical study to examine the relationship between serum level of PEDF and atherosclerosis in humans.

METHODS/RESULTS

The study involved 317 consecutive outpatients in Kurume University Hospital (220 male and 97 female) with a mean age of 62.1±9.1. We examined whether serum level of PEDF were independently associated with vascular inflammation evaluated by [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) and intima-media thickness (IMT) in carotid artery in humans. Carotid [(18)F]-FDG uptake, an index of vascular inflammation within the atherosclerotic plaques, was measured as standardized uptake value (SUV). Mean serum PEDF level, carotid SUV and IMT values were 13.5±1.1 μg/mL, 1.34±0.19, and 0.71±0.15 mm, respectively. In multiple stepwise regression analysis, estimated glomerular filtration rate (p<0.001), males (p<0.001), homeostasis model assessment of insulin resistance index (p<0.05), heart rate (p<0.05), triglycerides (p<0.05), carotid IMT (p<0.05), waist circumference (p<0.05) and carotid SUV (p<0.05) were independently correlated to PEDF level (R(2)=0.332).

CONCLUSION

The present study reveals that serum level of PEDF is independently associated with vascular inflammation and IMT, thus suggesting that PEDF level is a novel biomarker that could reflect atherosclerosis in humans.

Association between plasma pigment epithelium-derived factor levels and tissue characteristics of coronary plaque using integrated backscatter intravascular ultrasound

OBJECTIVE

Recent evidence has strongly suggested that atherosclerosis is an angiogenic disease, and PEDF may play a significant role in determining the balance of angiogenesis/antiangiogenesis during atherogenesis. Therefore, we assessed the associations among plasma levels of pigment epithelium-derived factor (PEDF), high-sensitivity C-reactive protein (hsCRP), the lipid profile and tissue characteristics of coronary plaque as assessed by integrated backscatter intravascular ultrasound (IB-IVUS).

METHODS

Fifty-two consecutive patients with stable coronary artery disease who underwent percutaneous coronary intervention were enrolled. Non-target coronary lesions with mild to moderate stenosis were measured by IB-IVUS. A total of 20 IB-IVUS images were recorded at an interval of 0.5 mm for a length of 10 mm in each plaque.

RESULTS

Although the percentage of plaque volume (%PV, 100×total PV/total vessel volume), percentage of lipid volume (%LV, 100×LV/PV) and percentage of fibrous volume (%FV, 100×FV/PV) were not associated with plasma log[PEDF] levels in the overall patients, in the patients without statin treatment %LV and %FV were correlated with plasma log[PEDF] levels (r=0.525, p=0.021 and r=-0.498, p=0.030, respectively).

CONCLUSION

The plasma level of PEDF may be a useful biomarker for predicting the tissue characteristics of coronary plaque using IB-IVUS.