Open Access

Serum fibroblast growth factor 21 levels is associated with lower extremity atherosclerotic disease in Chinese female diabetic patients

Contributed equally
Cardiovascular Diabetology201514:32

https://doi.org/10.1186/s12933-015-0190-7

Received: 2 December 2014

Accepted: 9 February 2015

Published: 11 March 2015

Abstract

Background

Fibroblast growth factor 21 (FGF21) is an emerging metabolic regulator associated with glucose and lipid metabolism, and it is still unclear whether FGF21 is related to atherosclerosis. Here, we explored the potential link between FGF21 and lower extremity atherosclerotic disease (LEAD) in type 2 diabetic patients.

Methods

A cross-sectional study was conducted on 504 type 2 diabetic patients (283 men, 221 women). LEAD was defined by Ankle-brachial index (ABI) <0.9 and lower extremity arterial plaque evaluated by color Doppler ultrasound. Serum FGF21 concentrations were quantified by a sandwich enzyme-linked immunosorbent assay.

Results

The total FGF21 levels of male and female patients had no significant differenence ((299.14(177.31-534.49) vs 362.50(214.01-578.73), P=0.516). Serum FGF21 levels in LEAD group were significantly higher than non-LEAD group in females (385.34(243.89-661.54) vs 313.13(156.38-485.79), P=0.006), while not in male patients (295.52(177.09-549.64) vs 342.09 (198.70-549.87), P=0.613). In diabetic women, subjects with LEAD had significantly higher serum FGF21 regardless of non-alcoholic fatty liver disease (NAFLD) (P < 0.05). And serum FGF21 levels were positively correlated with waist circumference and systolic blood pressure after adjusted for age and BMI (r=0.198, P=0.004; r=0.152, P=0.027; respectively). Moreover, FGF21 was independently tied to femoral intima-media thickness (FIMT) (β=0.208, P=0.031). After adjusted for other LEAD risk factors, FGF21 was demonstrated to be an independent risk factor for LEAD in type 2 diabetic women (OR, 1.106; 95%CI 1.008-1.223; P=0.028). In addition, FGF21 was negatively correlated with estradiol in premenopausal diabetic women (r=−0.368, P=0.009). After adjusted for estradiol, serum FGF21 levels were still positively associated with FIMT in premenopausal diabetic women (r=0.381, P=0.007). In diabetic men, serum FGF21 levels were correlated with triglyceride and C-reactive protein even after adjusted for age and BMI (r=0.204, P=0.001; r=0.312, P < 0.001; respectively). However, serum FGF21 was not an independent impact factor for LEAD in men (P > 0.05).

Conclusions

Serum FGF21 level independently and positively links LEAD in Chinese women with type 2 diabetes. The gender difference may be due to different estrogen levels.

Keywords

Fibroblast growth factor 21Lower extremity atherosclerotic diseaseType 2 diabetes

Background

Atherosclerosis is a progressive disease which affects multiple vascular beds. And its clinical consequence including coronary arterial disease, cerebrovascular disease and peripheral artery disease (PAD) are potentially life-threatening. Even the patients with higher subclinical atherosclerosis risk have significantly higher cumulative incidence rate of cardiovascular events [1]. In diabetic patients, the onset of atherosclerosis was earlier [2]. Diabetics had significantly higher pulse wave velocity, increased carotid intima-medial thickness and more plagues than non-diabetes [3]. In fact, atherosclerotic lesions were more frequent in femoral arteries than carotid arteries independent of increasing number of risk factors [4]. As one of common diabetic macrovascular complications, lower extremity atherosclerotic disease (LEAD) or diabetic PAD of lower extremity, was one of the major causes of foot ulceration and amputation [5]. Early detection and treatment of LEAD is critical to prevent amputation and mortality of diabetic population. Despite the fact that LEAD is an independent predictor of cardiovascular and cerebrovascular ischemic events, this particular manifestation of systemic atherosclerosis is largely under-diagnosed and undertreated [6]. Therefore, it is vital for diabetic patients to recognize lower limb atherosclerosis and control its risk factors as early as possible.

Fibroblast growth factors and their receptors have a wide range of biological functions. As we all known, basic fibroblast growth factor (bFGF), one of FGFs isomer, is involved in atherosclerosis formation [7]. But as a member of the FGFs subfamily, fibroblast growth factor 21 (FGF21) plays an important role in regulating glucose and lipid metabolism and insulin sensitivity in animals. Pharmacological doses of FGF21 produce anti-diabetic, lipid-lowering, and weight-reducing effects in rodents. And mice with over-expression of FGF21 were protected from diet-induced obesity [8], while FGF21 knockout mice developed mild obesity and impaired glucose homeostasis as these mice became aged [9]. Gaich et al. reported the first clinical trial that FGF21 analog improved the lipid profile of obese subjects with type 2 diabetes [10]. And FGF21 may be a promising therapeutic target in obesity-related diseases [11]. Actually, despite of FGF21 reduction in type 1 diabetes and latent autoimmune diabetes in adults (LADA) [12], circulating FGF21 levels were elevated in obesity [13], type 2 diabetes [14], dyslipidemia [15] and non-alcoholic fatty liver disease (NAFLD) [16]. Shen Y et al. also showed that FGF21 concentrations increased in coronary heart disease [17] and “FGF21 resistance”, a phenomenon reminiscent of hyperinsulinemia and insulin resistance might be one of the reasons for the increase of elevated FGF21 [18].

Except for these above findings that FGF21 was associated with metabolic dysfunction and the well-established link between metabolic disorders and cardiovascular disease, few clinical studies have reported the potential connection between FGF21 and atherosclerosis especially LEAD. An SY et al. found that subjects with carotid artery plaque had higher serum FGF21 levels than those without complications [19]. A study from Ulu SM et al. indicated that FGF21 was an independent determinant of arterial stiffness in patients on dialysis [20]. Thus, the aim of the present study was to clarify the possible link between serum FGF21 levels and LEAD in diabetes patients.

Research design and methods

Study population

Consecutive 504 type 2 diabetic inpatients at the Shanghai Clinical Medical Center of Diabetes from January 2013 to December 2013 were enrolled in the study. They were mainly local from 16 districts of Shanghai and were admitted for uncontrolled hyperglycemia or diabetic complications. The diagnostic criteria of diabetes was based on the American Diabetes Association standards [21]. Patients with type 1 diabetes, other specific types of diabetes or acute complications of diabetes were excluded. All the enrolled patients continued their previous glycemic control regimen including hypoglycemic drugs and (or) insulin. The study was approved by the Ethics Committee of the Shanghai Jiao-Tong University Affiliated Sixth People’s Hospital. The informed consents were completed by all the participants, which were abided by the principle of the Declaration of Helsinki.

Data collection

All subjects completed a questionnaire that collected general background information including present and previous illness, medication, alcohol consumption and smoking status. Hypertension was defined as systolic blood pressure (SBP) 140 mmHg or diastolic blood pressure (DBP) 90 mmHg or history of antihypertensive medicine administration. Height, weight, waist circumference (W) and blood pressure were assessed on a standardized form by the same physician during the health check-up. Body mass index (BMI) was calculated as body weight (in kg) divided by the square of the height (in m). All the patients had an overnight fast prior to the blood samples collection.

Laboratory measurements

Blood samples were transported to the laboratory of Shanghai Clinical Medical Center of Diabetes as needed after collected. Fasting plasma glucose (FPG) and 2-hour postprandial plasma glucose (2hPG) were measured by glucose oxidase method. Glycosylated hemoglobin A1c (HbA1c) was determined by high-pressure liquid chromatography and glycated serum albumin (GA) was measured by the liquid enzymatic assay. Serum alanine aminotransferase (ALT) and serum lipids including total cholesterol (TC), triglyceride (TG), highdensity lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) were performed by enzymatic method. The glomerular filtration rate (GFR) was determined by technetium-99 m diethyl triamine penta-acetic acid (Tc99m-DTPA) clearance. Serum C-reactive protein (CRP) was measured by particle-enhanced immunonephelometric assay (Dade Behring Inc., Newark, NJ, USA). The serum sex hormone including testosterone (T), estradiol (E2), progesterone (P), luteinizing hormone (LH), follicle stimulating hormone(FSH), prolactin (PRL), dehydroepiandrosterone sulfate(DHEA-S) were tested by Chemoluminescence (Diasorin company, Italy). Serum FGF21 concentration was determined by enzyme-linked immunosorbent assay (ELISA) (Antibody and Immunoassay services, University of Hong Kong), which give intra-batch and inter-batch variations were 7.8% and 9.1%, respectively. Serial dilutions of recombinant FGF21 were included in all assays as a standard. Duplicate measurements were obtained for all samples.

ABI and Ultrasonography measurements

American Nieolet Versalab duplex doppler blood flow detector was used to determine brachial and ankle arterial pressure. Patients supine, with 12 cm × 40 cm gas sleeve respectively in bilateral ankle and upper arm, with doppler stethoscope to assist the acquisition dorsalis pedis or tibial artery, posterior tibial artery and brachial artery systolic blood pressure. Ankle-brachial index (ABI) was calculated by the higher SBP in the dorsalis pedis and posterior tibial artery devided by the higher brachial SBP. The lower value of ABI in either limb was used for analysis. The arterial lesion of lower extremity artery were evaluated by color Doppler ultrasound examination, and the femoral intima-media thickness (FIMT) were also recorded. Color duplex ultrasonography was conducted by three trained, certified sonographers using a Acuson Sequoia 512 scanner (Siemens Medical Solutions, Mountain View, CA) with a 5–13 MHz linear transducer according to our previous method [22]. The study procedure involved scanning bilateral common femoral artery, profunda femoris artery, superficial femoral artery, popliteal artery, anterior tibial artery, posterior tibial artery, and peroneal artery for the presence of atherosclerotic plaque and stenosis. The FIMT on both sides was measured as the distance between the leading edge of the lumen-intima echo and the leading edge of the media-adventitia echo. Mean FIMT was defined as the mean values of bilateral FIMTs. Lower limb atherosclerotic plaque was defined as the presence of a focal structure encroaching into the arterial lumen of 0.5 mm or at least 50% greater than the thickness of the surrounding vessel wall or IMT of >1.5 mm in any of the above-mentioned lower limb arteries segments based on the Mannheim consensus [23]. LEAD was defined by ABI < 0.9 and lower extremity arterial plaque existed. Those with an ABI > 1.3 were excluded from the analysis to avoid those with significant medical artery layer calcification, which is independent of atherosclerotic plagues. Others individuals were named as non-LEAD.

Diagnostic criteria for non-alcoholic fatty liver disease(NALFD)

NALFD was diagnosed by B ultrasonography. Hepatic steatosis was defined by a diffuse increase of fine echoes in the liver parenchyma compared with that in the kidney or spleen parenchyma according to the 2010 Prevention and Treatment Guidelines for NALFD published by the society of Hepatology, Chinese Medical Association [24].

Data analysis

All the statistical analysis was performed by SPSS 21.0 (SPSS Inc., Chicago, IL). The one-sample Kolmogorov-Smirnov test was performed to determine normality of the data distribution. Normally distributed data were expressed as mean ± standard deviation (SD), and data with skewed distribution were expressed as median with interquartile range. Differences between groups were evaluated with Student’s t test or Mann–Whitney U test. Categorical variables were presented as frequency percentage, and intergroup comparisons were analyzed using a Chi-square test. The association between FGF21 and other variables were evaluated with Spearman correlation and partial correlation analysis. Logistic regression analysis was performed to evaluate the odds ratio of LEAD. Multiple stepwise regression analysis was used to explore the influence of different variables on FIMT. To determine the independent predictors for the presence of LEAD, all the conventional risk factors related with LEAD as well as the disease-related therapies were tested in multivariable logistic regression. The threshold of statistical significance was set at 0.05 for two-tailed P-values.

Results

The mean age of the 504 study subjects was 58 years, the media diabetes duration was 9 years, and the median level of serum FGF21 was 327.03 ng/mL, with an interquartile range of 190.05–545.55 ng/mL. Comparison of the prevalence of LEAD stratified by sex and age was shown in Figure 1. The prevalence of LEAD significantly increased with age both in diabetic men and women (P < 0.05). FGF21 levels were not significantly different between male and female patients (299.14(177.31-534.49) vs 362.50 (214.01-578.73), P = 0.516).
Figure 1

Comparison of prevalence of LEAD stratified by age and sex in type 2 diabetic patients. White bars: men; black bars: women. Trend analysis, p < 0.001.

The clinical characteristics of LEAD and non-LEAD patients with respect to sex are shown in Table 1. In female subgroup, there were significant differences in age, diabetes duration, SBP, prevalence of hypertension and anti-hypertensive therapy between LEAD and non-LEAD patients (P < 0.05). In male subgroup, there were significant differences in age, diabetes duration, prevalence of hypertension and anti-hypertensive therapy, FPG, TC, TG, LDL-C, HbA1c and GA between LEAD and non-LEAD patients (P < 0.05). FIMT values were significantly higher in LEAD than in non-LEAD group in both male patients and female patients (P < 0.05). Serum levels of FGF21 in LEAD group were significantly higher than non-LEAD group in female patients (385.34(243.89-661.54) vs. 313.13(156.38-485.79), P = 0.006), while not in male patients (295.52(177.09-549.64) vs. 342.09(198.70-549.87), P = 0.613) (Figure 2). As is shown in Figure 3, both subjects with and without NAFLD showed a significant elevation of serum FGF21 levels in the LEAD group compared to the non-LEAD group (P < 0.05).
Table 1

Clinical and biochemical characteristics of participants

Variables

Men

P

Women

P

LEAD

Non-LEAD

LEAD

Non-LEAD

Age(year)

61.75 ± 10.31

47.55 ± 10.07

<0.001

64.40 ± 9.79

56.62 ± 9.52

<0.001

Diabetes duration(year)

10(5–15)

3(0.48-10)

<0.001

13.14 ± 7.73

7.85 ± 5.64

<0.001

Body mass index(kg/cm2)

23.59 ± 3.53

25.99 ± 3.20

0.194

25.12 ± 3.83

25.37 ± 3.89

0.655

Waist circumference(cm)

93.23 ± 10.89

94.80 ± 10.17

0.273

91.19 ± 11.35

88.02 ± 10.49

0.055

Systolic blood pressure(mmHg)

130(120–140)

130(120–140)

0.503

135(123.5-150)

129(120–135)

<0.001

Diastolic blood pressure(mmHg)

80(70–85)

80(78–90)

0.010

80(75–85)

80(70–85)

0.268

Fasting plasma glucose(mmol/L)

6.88(5.92-9.07)

7.92(6.50-10.36)

0.007

8.03 ± 2.62

2.97 ± 0.91

0.409

2 h postprandial plasma glucose(mmol/L)

12.96 ± 4.40

13.73 ± 4.53

0.212

14.31 ± 4.57

13.48 ± 4.61

0.232

Fasting C-peptide(ng/ml)

1.93 ± 1.03

2.12 ± 1.13

0.213

1.95 ± 1.07

2.07 ± 1.15

0.472

2-h postprandial C peptide(ng/ml)

4.98 ± 3.18

5.07 ± 3.50

0.854

4.90 ± 3.26

5.11 ± 2.99

0.664

Total cholesterol(mmol/L)

4.46 ± 1.11

4.98 ± 1.17

0.001

4.92 ± 1.10

5.08 ± 1.16

0.352

Triglyceride(mmol/L)

1.92(1.16-3.63)

1.40(0.93-2.10)

0.005

1.42(1.05-1.93)

1.46(0.98-2)

0.720

High-density lipoprotein cholesterol(mmol/L)

1.00 ± 0.24

0.97 ± 0.21

0.397

1.15 ± 0.32

1.18 ± 0.33

0.481

Low-density lipoprotein cholesterol(mmol/L)

2.63 ± 0.89

2.96 ± 0.80

0.006

2.86 ± 0.97

2.97 ± 0.91

0.409

Glycated hemoglobin A1c(%)

8.0(7.1-9.85)

9.1(7.45-10.85)

0.023

8.82 ± 1.86

8.62 ± 1.85

0.459

Glycated serum albumin(%)

22.30 ± 7.18

24.44 ± 8.07

0.044

20.9(17.75-26.30)

20.10(17.20-25.3)

0.364

Alanine aminotransferase(U/L)

21(14–27)

24(18–36.5)

0.065

18(13–31.75)

22(14.75-30)

0.303

Aspartate aminotransferase(U/L)

19(16–23)

19(15–28)

0.423

19(16–24)

20(15–25.5)

0.894

γ-glutamyl transpeptidase(U/L)

27(19–39)

31(21–42.5)

0.065

23(16.75-39)

28(18.50-44)

0.160

Glomerular filtration rate(ml/min/1.73 m2)

97.04 ± 24.04

96.34 ± 24.92

0.845

94.67 ± 25.79

98.37 ± 23.23

0.355

C reactive protein(mg/L)

1.67(0.64-2.57)

1.10(0.56-2.35)

0.347

1.3(0.53-2.65)

1.45(0.75-3.11)

0.256

Femoral intima-media thickness(mm)

0.85 ± 0.06

0.67 ± 0.12

<0.001

0.86 ± 0.03

0.70 ± 0.11

<0.001

Smoking(%)

55.8

54.9

0.888

0.8

2.7

0.278

Drinking(%)

24.5

19.5

0.233

1.6

1.4

0.903

Hypertension(%)

60.7

36.6

<0.001

62.7

37.0

<0.001

Anti-hypertensive therapy(%)

47.1

18.9

<0.001

48.6

20.3

<0.001

Anti-diabetic therapy(%)

78.9

77.1

0.732

68.9

66.4

0.453

Lipid-lowing therapy(%)

15.8

14.3

0.677

12.8

10.3

0.566

Estradiol

115.24 ± 58.72

116.54 ± 56.01

0.889

70.94(38.73-104.91)

88.95(50.10-165.27)

0.039

Testosterone

12.61 ± 5.25

12.64 ± 4.56

0.972

1.18(0.89-1.55)

1.26(0.94-1.69)

0.610

Progestogen

1.04(0.75-1.47)

1.03(0.71-1.33)

0.516

0.82(0.65-1.42)

0.80(0.64-1.90)

0.756

Follicle-Stimulating Hormone

9.43(6.40-14.41)

6.50(4.00-9.04)

<0.001

52.53 ± 23.61

38.08 ± 25.33

0.001

Luteinizing hormone

5.92(3.98-9.56)

4.96(3.24-6.48)

0.002

23.78 ± 10.53

20.16 ± 13.69

0.960

Prolactin

168.83(136.86-214.16)

171.39(109.74-242.44)

0.002

193.70 ± 85.48

185.66 ± 138.83

0.707

Dehydroepiandrosterone sulfate

201.13 ± 106.74

260.10 ± 117.77

0.001

126.50 ± 66.74

173.73 ± 81.99

<0.001

Figure 2

Comparison of serum FGF21 levels in LEAD and non-LEAD subgroup stratified by sex. White bars: men; Grey bars: women.

Figure 3

Serum FGF21 levels among subjects with NAFLD and/or LEAD (data from women only). White bars: non-LEAD; Grey bars: LEAD.

In order to find out the influencing factors for FGF21, Spearman correlation analysis of clinical and biochemical parameters with FGF21 were undertaken. In female patients, FGF21 was positively correlated with age, BMI, W, SBP, DBP, TG, FCP and 2hCP, but was negatively associated with HDL-C (P < 0.05). Serum FGF21 level was not correlated with CRP in female patients (P > 0.05). Even after adjusted for age and BMI, FGF21 was still positively associated with W and SBP (r = 0.198, P = 0.004; r = 0.152, P = 0.027; respectively). In male group, serum FGF21 level was correlated with TG and CRP (P < 0.05) (Table 2). After adjusted for age and BMI, FGF21 level was still correlated with TG and CRP (r = 0.204, P = 0.001; r = 0.312, P < 0.001; respectively).
Table 2

Correlation of FGF21 with anthropometric and biochemical variables

Covariables

Women

Men

r

P

r

P

Age(year)

0.031

0.647

−0.011

0.858

Diabetes duration(year)

−0.030

0.662

−0.015

0.805

Body mass index(kg/cm2)

0.160

0.018

0.081

0.179

Waist circumference(cm)

0.188

0.005

0.074

0.218

Systolic blood pressure(mmHg)

0.200

0.003

−0.036

0.551

Diastolic blood pressure(mmHg)

0.176

0.009

−0.036

0.557

Fasting plasma glucose(mmol/L)

0.005

0.945

−0.003

0.958

2 h postprandial plasma glucose(mmol/L)

0.073

0.290

−0.092

0.139

Fasting C-peptide(ng/ml)

0.168

0.017

0.102

0.106

2-h postprandial C peptide(ng/ml)

0.149

0.034

0.014

0.845

Total cholesterol(mmol/L)

0.036

0.606

0.088

0.160

Triglyceride(mmol/L)

0.245

<0.001

0.21

0.001

High-density lipoprotein cholesterol(mmol/L)

−0.192

0.006

−0.091

0.147

Low-density lipoprotein cholesterol(mmol/L)

−0.044

0.524

−0.007

0.906

Glycated hemoglobin A1c(%)

0.047

0.493

0.057

0.366

Glycated serum albumin(%)

−0.001

0.985

−0.011

0.865

C reactive protein(mg/L)

0.150

0.032

0.222

<0.001

Femoral intima-media thickness(mm)

0.151

0.048

0.022

0.709

Since there was gender difference of association between FGF21 and LEAD, women were further divided into two subgroups and compared according whether menopause or not. There was no significant difference in FGF21 levels between menopausal and pre-menopausal women [360.51(228.16-529.75) vs 363.54(208.57-593.95), P > 0.05]. It showed that FGF21 was negatively correlated with E2 in premenopausal diabetic women (r = −0.368, P = 0.009) (Table 3). After adjusted for estradiol, serum FGF21 level was still positively associated with FIMT in premenopausal diabetic women (r = 0.381, P = 0.007).
Table 3

Correlation of FGF21 with sex hormone by Spearman analysis

Covariables

Postmenopausal (n = 143)

Premenopausal (n = 78)

Men (n = 283)

 

r

P

r

P

r

P

Estradiol

0.07

0.593

−0.368

0.009

0.092

0.212

Testosterone

0.029

0.795

0.149

0.288

−0.09

0.213

Progestogen

−0.221

0.201

−0.148

0.383

0.045

0.602

Follicle-Stimulating Hormone

−0.029

−0.798

0.009

0.949

−0.093

0.2

Luteinizing hormone

0.034

0.762

−0.104

0.456

0.003

0.966

Prolactin

−0.033

0.769

−0.147

0.288

0.113

0.122

Dehydroepiandrosterone sulfate

−0.076

0.493

0.212

0.123

−0.018

0.805

In order to determine which factors were independently associated with LEAD, logistic regression was performed. Independent variables were set as metabolic risk factors (including age, diabetes duration, smoking status, presence of hypertension,ALT, GFR, HbA1c, waist circumference, dyslipidemia, anti-diabetic therapy, anti-hypertensives, lipid-lowering therapy and serum FGF21 levels). In female patients, logistic regression analysis of LEAD showed that age (OR, 1.235; 95%CI (1.133-1.347); P < 0.001), hypertension (OR, 3.231; 95%CI 1.102-9.470; P = 0.033), FGF21 (OR, 1.106; 95%CI 1.008-1.223; P = 0.028) were independent impact factors for LEAD. In male patients, only age (OR, 1.171; 95%CI (1.097-1.249); P < 0.001) was independent associated factor for LEAD (Table 4). After adjustment for the confounding variables described above, multiple stepwise regression analysis showed that the age (β = 0.519, P < 0.001), FGF21 (β = 0.208, P = 0.031), HbA1c (β = 0.225, P = 0.020) were independent risk factors for FIMT in type 2 diabetes women. While in male patients, only age (β = 0.539, P < 0.001) was independently associated with FIMT (Table 5).
Table 4

Independent factors for LEAD in men and women by multivariable logistic regression analysis

 

β

S.E

Wald

OR(95% CI)

P

Female

     

Age

0.211

0.044

22.868

1.235(1.133-1.347)

<0.001

Hypertension

1.173

0.549

4.570

3.231(1.102-9.470)

0.033

FGF21

0.113

0.036

3.537

1.106(1.008-1.223)

0.028

Male

     

Age

0.157

0.033

22.719

1.171(1.097-1.249)

<0.001

Notation: S.E., standard error; OR, odds ratio; CI, confidence interval. Variables included in the model were age, diabetes duration, smoking status, presence of hypertension, ALT, GFR, HbA1c, W, dyslipidemia, anti-diabetic therapy, anti-hypertensives, lipid-lowering therapy and serum FGF21 levels.

Table 5

Multiple stepwise linear regression analysis of FIMT

 

Standardized β

t

P

Female

   

Age

0.519

5.495

<0.001

FGF21

0.208

2.202

0.031

HbA1c

0.225

2.387

0.020

Male

   

Age

0.539

0.254

<0.001

Notation: Variables included in the model were age, diabetes duration, smoking status, presence of hypertension, ALT, GFR, HbA1c, W, dyslipidemia, anti-diabetic therapy, anti-hypertensives, lipid-lowering therapy and serum FGF21 levels.

Discussions

In this study we provide the evidence for the first time that elevated serum FGF21 levels are associated with LEAD in female type 2 diabetic patients independent of established risk factors.

Our research group had shown that increased level of serum FGF21 was associated with NAFLD and mRNA expression of FGF21 has been shown to increase in hepatic biopsies [16]. Furthermore, a 3 year follow-up of NALFD subject outcome indicated that serum FGF21 level might be a clinically-relevant disease biomarker for NALFD [25]. In the current study, a significant elevation of serum FGF21 among LEAD subjects was found independently of NALFD status. Multivariable logistic regression analysis also identified serum FGF21 level as one of the independent risk factors for LEAD.

The mechanism linking FGF21 with atherosclerosis was currently not well understood. Elevated mRNA expression of FGF21 was found in rat cardiac micro-vascular endothelial cells (CMECs) cultured in atherosclerosis-like conditions [26]. Furthermore, exogenous FGF21 infusion to the CMECs atherosclerosis promoting culture significantly inhibited the apoptosis of cells. These findings suggested that up-regulated FGF21 expression might be protective at the early stage of atherosclerosis, helping the cells to recover normal endothelial function. FGF21 also has antioxidant effects in atherosclerotic rat, such that increased levels of superoxide dismutase, reduced glutathione, and reduced malondialdehyde [27]. Another study found the protective effect of FGF21 on atherosclerosis might be in part due to its inhibition on endoplasmic reticulum stress-mediated apoptosis [28].

Actually in human study, circulating FGF21 levels are elevated in obesity, type 2 diabetes and dyslipidemia. It was proposed that the elevated level of FGF21 was attributed to FGF21 resistance, a phenomenon reminiscent of hyperinsulinemia and insulin resistance. One of the reasons of elevated FGF21 could be the presence of compensatory response to higher metabolic stress. A recent study suggested that adipose tissue inflammation in obesity could lead to the repression of beta-Klotho expression by TNF alpha and impaired FGF21 in adipocytes [29]. Hence we can infer it is very likely that similar actions lead to the FGF21 resistance in subclinical inflammation such as LEAD. Thus, it is possible that the elevated FGF21 observed in the LEAD subjects of our study represent a similar compensatory mechanism, by which the system is attempting to protect against atherosclerosis.

In our study, we observed the gender-specific association between serum FGF21 and LEAD. Chow WS et al. also found this association was gender-specific, they found that serum FGF21 levels positively correlated with carotid IMT in women (r = 0.32; P < 0.001) but not in men (r = 0.06; P = 0.305) [30]. As we all know, E2 protected premenopausal women from cardiovascular disease. While in postmenopausal women, the prevalence of macrovascular diseases was higher. Based on these observations, the relationship between FGF21 and hormonal parameters were assessed in our study. In our data, it was found that FGF21 was negatively correlated with E2 in diabetic women. In polycystic ovary syndrome and healthy subjects, a positive correlation was also found between FGF21 and LH and T (r = 0.43 p = 0.007; r = 0.38, P = 0.02, respectively) [31]. Another study found there was a significantly negative correlation between FGF21 and dehydroepiandrosterone sulfte (DHEAS) (r = −0.309 p = 0.003) [32]. This significant correlation between FGF21 and sex hormone in our study group arises a need of new studies to explain the potential role of FGF21 in atherosclerosis pathogenesis. Our finding of the gender-specific association between serum FGF21 and LEAD remains to be confirmed in further studies.

In our study, FGF21 was found to positively correlated to BMI, W, TG, but negatively link with HDL-C in diabetic patients. Some of these relationships have been described in the previous studies [13,33,34]. But there are only limited information about the relationships of FGF21 and hypertension in literature. In our study, positive associations of FGF21 and SBP were found in diabetic patients. The same result was found in Japanese subjects [35]. CRP reflecting systemic inflammation, was a well-established marker of atherosclerosis and one of the classical biomarkers for increasing risk of PAD [36]. And CRP might play a role in the progression of PAD in diabetic patients [37]. A recent study of 69 newly diagnosed diabetes subjects demonstrated a positive correlation between serum FGF21 levels and CRP [38]. Similarly, serum FGF21 levels also linked with CRP in the present study (r = 0.15 P = 0.032).

Consistent with other studies, we found that some of the traditional risk factors for atherosclerosis were also present in this population. As expected, age, hypertension were independently associated with the presence of LEAD in the type 2 diabetes women. Therefore, strict control of hypertension is important in order to prevent atherosclerosis in the lower limb arteries in diabetic patients.

The strength of this study is that GFR was directly measured by the 99mTc-DTPA renal dynamic imaging rather than estimated from serum creatinine, which was more accurate and avoided the impact from serum creatinine. Several previous studies reported a close association between chronic renal insufficiency and PAD [39]. Our previous study also revealed that the degree of peripheral arterial lesion was significantly correlated with renal function and GFR. In our study, the difference of GFR between LEAD and Non-LEAD women patients was not significant, the increased serum FGF21 did not result in the dysfunction of kidney.

Lenart-Lipińska M et al. showed that serum FGF21 is predictive of combined cardiovascular morbidity and mortality in patients with type 2 diabetes at 24 months follow-up [40]. Another larger scale study showed higher baseline plasma FGF21 levels were associated with higher risk of cardiovascular events in patients with type 2 diabetes over 5 years follow-up in 9,697 individuals with type 2 diabetes participating in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study [41]. A follow-up of the outcome in LEAD subjects is necessary to elucidate whether serum FGF21 level might be a clinically-relevant vascular disease biomarker.

Limitations

There were some limitations of our study. Firstly, the cross-sectional design restricted our ability to assess the evolutionary process of atherosclerotic lesions. Secondly, this was merely a single-center study with a relatively small number of patients. Thirdly, some other confounding affecting factors of LEAD were not excluded. Further in vivo and in vitro studies are needed to elucidate the essential relationship between FGF21 and LEAD and the underlying detailed mechanism in diabetes.

Conclusion

In conclusion, serum FGF21 levels independently and positively connect with LEAD in Chinese women with type 2 diabetes after adjusted for the traditional risk factors, and its gender difference may be due to the difference of estrogen levels. Further studies revealing the immanent connection of FGF21 with the pathology of diabetic peripheral vascular disorders may provide a new prospective strategy for LEAD.

Notes

Abbreviations

BMI: 

Body mass index

W: 

Waistcircumference

ALT: 

Alanine aminotransferase

AST: 

Aspartate aminotransferase

γ-GT: 

γ-glutamyl transpeptidase

GFR: 

Glomerular filtration rate

FPG: 

Fasting plasma glucose

2hPG: 

2 h postprandial plasma glucose

HbA1c: 

Glycated hemoglobin A1c

GA: 

Glycated serum albumin(%)

FCP: 

Fasting C-peptide

2hCP: 

2-h postprandial C peptide

TC: 

Total cholesterol

TG: 

Triglyceride

HDL-C: 

High-density lipoprotein cholesterol

LDL-C: 

Low-density lipoprotein cholesterol

Declarations

Acknowledgments

This study was supported by the grants from National Science Foundation of China (81270397 for Fang Liu, 81170759 for Lianxi Li).

Authors’ Affiliations

(1)
Department of Endocrinology & Metabolism, Shanghai Jiao-Tong University Affiliated Sixth People’s Hospital; Shanghai Clinical Medical Center of Diabetes; Shanghai Key Clinical Center of Metabolic Diseases; Shanghai Institute of Diabetes; Shanghai Key Laboratory of Diabetes
(2)
Department of Interventional Radiology, Shanghai Jiao-Tong University Affiliated Sixth People’s Hospital
(3)
Department of Vascular Surgery, Shanghai Jiao-Tong University Affiliated Sixth People’s Hospital

References

  1. Katakami N, Osonoi T, Takahara M, Saitou M, Matsuoka TA, Yamasaki Y. Clinical utility of brachial-ankle pulse wave velocity in the prediction ofcardiovascular events in diabetic patients. Cardiovasc Diabetol. 2014;13:128.View ArticlePubMed CentralPubMedGoogle Scholar
  2. American Diabetes Association. Peripheral arterial disease in people with diabetes. Diabetes Care. 2003;26:3333–41.View ArticleGoogle Scholar
  3. Won KB, Chang HJ, Kim HC, Jeon K, Lee H, Shin S, et al. Differential impact of metabolic syndrome on subclinical atherosclerosis according to the presence of diabetes. Cardiovasc Diabetol. 2013;12:41.View ArticlePubMed CentralPubMedGoogle Scholar
  4. Kroger K, Kucharczik A, Hirche H, Rudofsky G. Atherosclerotic lesions are more frequent in femoral arteries than in carotid arteries independent of increasing number of risk factors. Angiology. 1999;50:649–54.View ArticlePubMedGoogle Scholar
  5. Scholte AJ, Schuijf JD, Kharagjitsingh AV, Jukema JW, Pundziute G, van der Wall EE, et al. Prevalence of coronary artery disease and plaque morphology assessed by multi-slice computed tomography coronary angiography and calcium scoring in asymptomatic patients with type 2 diabetes. Heart. 2008;94:290–5.View ArticlePubMedGoogle Scholar
  6. Marso SP, Hiatt WR. Peripheral arterial disease in patients with diabetes. J Am Coll Cardiol. 2006;47:921–9.View ArticlePubMedGoogle Scholar
  7. Gui C, Li SK, Nong QL, Du F, Zhu LG, Zeng ZY. Changes of serum angiogenic factors concentrations in patients with diabetes and unstable angina pectoris. Cardiovasc Diabetol. 2013;12:34.View ArticlePubMed CentralPubMedGoogle Scholar
  8. Kharitonenkov A, Shiyanova TL, Koester A, Ford AM, Micanovic R, Galbreath EJ, et al. FGF-21 as a novel metabolic regulator. J Clin Invest. 2005;115:1627–35.View ArticlePubMed CentralPubMedGoogle Scholar
  9. Badman MK, Koester A, Flier JS, Kharitonenkov A, Maratos-Flier E. Fibroblast growth factor 21-deficient mice demonstrate impaired adaptation to ketosis. Endocrinology. 2009;150:4931–40.View ArticlePubMed CentralPubMedGoogle Scholar
  10. Gaich G, Chien JY, Fu H, Glass LC, Deeg MA, Holland WL, et al. The effects of LY2405319, an FGF21 analog, in obese human subjects with type 2 diabetes. Cell Metab. 2013;18:333–40.View ArticlePubMedGoogle Scholar
  11. Cheung BM, Deng HB. Fibroblast growth factor 21: a promising therapeutic target in obesity-related disease. Expert Rev Cardiovasc Ther. 2014;12:659–66.View ArticlePubMedGoogle Scholar
  12. Xiao Y, Xu A, Law LS, Chen C, Li H, Li X, et al. Distinct changes in serum fibroblast growth factor 21 levels in different subtypes of diabetes. J Clin Endocrinol Metab. 2012;97:E54–8.View ArticlePubMedGoogle Scholar
  13. Zhang X, Yeung DC, Karpisek M, Stejskal D, Zhou ZG, Liu F, et al. Serum FGF21 levels are increased in obesity and are independently associated with the metabolic syndrome in humans. Diabetes. 2008;57:1246–53.View ArticlePubMedGoogle Scholar
  14. Chavez AO, Molina-Carrion M, Abdul-Ghani MA, Folli F, Defronzo RA, Tripathy D. Circulating fibroblast growth factor-21 is elevated in impaired glucose tolerance and type 2 diabetes and correlates with muscle and hepatic insulin resistance. Diabetes Care. 2009;32:1542–6.View ArticlePubMed CentralPubMedGoogle Scholar
  15. Li H, Bao Y, Xu A, Pan X, Lu J, Wu H, et al. Serum fibroblast growth factor 21 is associated with adverse lipid profiles and gamma-glutamyltransferase but not insulin sensitivity in Chinese subjects. J Clin Endocrinol Metab. 2009;94:2151–6.View ArticlePubMedGoogle Scholar
  16. Li H, Fang Q, Gao F, Fan J, Zhou J, Wang X, et al. Fibroblast growth factor 21 levels are increased in nonalcoholic fatty liver disease patients and are correlated with hepatic triglyceride. J Hepatol. 2010;53:934–40.View ArticlePubMedGoogle Scholar
  17. Shen Y, Ma X, Zhou J, Pan X, Hao Y, Zhou M, et al. Additive relationship between serum fibroblast growth factor 21 level and coronary artery disease. Cardiovasc Diabetol. 2013;12:124.View ArticlePubMed CentralPubMedGoogle Scholar
  18. Fisher FM, Chui PC, Antonellis PJ, Bina HA, Kharitonenkov A, Flier JS, et al. Obesity is a fibroblast growth factor 21 (FGF21)-resistant state. Diabetes. 2010;59:2781–9.View ArticlePubMed CentralPubMedGoogle Scholar
  19. An SY, Lee MS, Yi SA, Ha ES, Han SJ, Kim HJ, et al. Serum fibroblast growth factor 21 was elevated in subjects with type 2 diabetes mellitus and was associated with the presence of carotid artery plaques. Diabetes Res Clin Pract. 2012;96:196–203.View ArticlePubMedGoogle Scholar
  20. Ulu SM, Yuksel S, Altunta힊 A, Kacar E, Ahsen A, Altug A, et al. Associations between serum hepcidin level, FGF-21 level and oxidative stress with arterial stiffness in CAPD patients. Int Urol Nephrol. 2014;46:2409–14.View ArticlePubMedGoogle Scholar
  21. American Diabetes Association. Standards of medical care in diabetes--2014. Diabetes Care. 2014;37 Suppl 1:S14–80.View ArticleGoogle Scholar
  22. Li L, Yu H, Zhu J, Wu X, Liu F, Zhang F, et al. The combination of carotid and lower extremity ultrasonography increases the detection of atherosclerosis in type 2 diabetes patients. J Diabetes Complications. 2012;26:23–8.View ArticlePubMedGoogle Scholar
  23. Touboul PJ, Hennerici MG, Meairs S, Adams H, Amarenco P, Desvarieux M, et al. Mannheim intima-media thickness consensus. Cerebrovasc Dis. 2004;18:346–9.View ArticlePubMedGoogle Scholar
  24. Jian-Gao, Chinese Liver Disease Association: Guildlines for management of nonalcoholic fatty liver disease. An updated and revised edition. Zhuang Hua Gan Zang Bing Za Zhi. 2010;18:163–6. in Chinese.Google Scholar
  25. Li H, Dong K, Fang Q, Hou X, Zhou M, Bao Y, et al. High serum level of fibroblast growth factor 21 is an independent predictor of non-alcoholic fatty liver disease: a 3-year prospective study in China. J Hepatol. 2013;58:557–63.View ArticlePubMedGoogle Scholar
  26. Wattanakit K, Folsom AR, Selvin E, Coresh J, Hirsch AT, Weatherley BD. Kidney function and risk of peripheral arterial disease: results from the Atherosclerosis Risk in Communities (ARIC) Study. J Am Soc Nephrol. 2007;18:629–36.View ArticlePubMedGoogle Scholar
  27. Zhu W, Wang C, Liu L, Li Y, Li X, Cai J, et al. Effects of fibroblast growth factor 21 on cell damage in vitro and atherosclerosis in vivo. Can J Physiol Pharmacol. 2014;92:927–35.View ArticlePubMedGoogle Scholar
  28. Wu X, Qi YF, Chang JR, Lu WW, Zhang JS, Wang SP, et al. Possible role of fibroblast growth factor 21 on atherosclerosis via amelioration of endoplasmic reticulum stress-mediated apoptosis in apoE(−/−) mice. Heart Vessels. 2014; [Epub ahead of print]Google Scholar
  29. Díaz-Delfín J, Hondares E, Iglesias R, Giralt M, Caelles C, Villarroya F. TNF-α represses β-Klotho expression and impairs FGF21 action in adipose cells: involvement of JNK1 in the FGF21 pathway. Endocrinology. 2012;153:4238–45.View ArticlePubMedGoogle Scholar
  30. Chow WS, Xu A, Woo YC, Tso AW, Cheung SC, Fong CH, et al. Serum fibroblast growth factor-21 levels are associated with carotid atherosclerosis independent of established cardiovascular risk factors. Arterioscler Thromb Vasc Biol. 2013;33:2454–9.View ArticlePubMedGoogle Scholar
  31. Gorar S, Culha C, Uc ZA, Dellal FD, Serter R, Aral S, et al. Serum fibroblast growth factor 21 levels in polycystic ovary syndrome. Gynecol Endocrinol. 2010;26:819–26.View ArticlePubMedGoogle Scholar
  32. Sahin SB, Ayaz T, Cure MC, Sezgin H, Ural UM, Balik G, et al. Fibroblast growth factor 21 and its relation to metabolic parameters in women with polycystic ovary syndrome. Scand J Clin Lab Invest. 2014;74:465–9.View ArticlePubMedGoogle Scholar
  33. Lin Z, Wu Z, Yin X, Liu Y, Yan X, Lin S, et al. Serum levels of FGF-21 are increased in coronary heart disease patients and are independently associated with adverse lipid profile. PLoS One. 2010;5:e15534.View ArticlePubMed CentralPubMedGoogle Scholar
  34. Lee Y, Lim S, Hong ES, Kim JH, Moon MK, Chun EJ, et al. Serum FGF21 concentration is associated with hypertriglyceridaemia, hyperinsulinaemia and pericardial fat accumulation, independently of obesity, butnot with current coronary artery status. Clin Endocrinol (Oxf). 2014;80:57–64.View ArticleGoogle Scholar
  35. Jin QR, Bando Y, Miyawaki K, Shikama Y, Kosugi C, Aki N, et al. Correlation of fibroblast growth factor 21 serum levels with metabolic parameters in Japanese subjects. J Med Invest. 2014;61:28–34.View ArticlePubMedGoogle Scholar
  36. Singh D, Whooley MA, Ix JH, Ali S, Shlipak MG. Association of cystatin C and estimated GFR with inflammatory biomarkers: the Heart and Soul Study. Nephrol Dial Transplant. 2007;22:1087–92.View ArticlePubMed CentralPubMedGoogle Scholar
  37. Bosevski M, Bosevska G, Stojanovska L. Influence of fibrinogen and C-RP on progression of peripheral arterial disease intype 2 diabetes: a preliminary report. Cardiovasc Diabetol. 2013;12:29.View ArticlePubMed CentralPubMedGoogle Scholar
  38. Li X, Fan X, Ren F, Zhang Y, Shen C, Ren G, et al. Serum FGF21 levels are increased in newly diagnosed type 2 diabetes with nonalcoholic fatty liver disease and associated with hsCRP levels independently. Diabetes Res Clin Pract. 2011;93:10–6.View ArticlePubMedGoogle Scholar
  39. O’Hare AM, Glidden DV, Fox CS, Hsu CY. High prevalence of peripheral arterial disease in persons with renal insufficiency: results from the National Health and Nutrition Examination Survey 1999–2000. Circulation. 2004;109:320–3.View ArticlePubMedGoogle Scholar
  40. Lenart-Lipińska M, Matyjaszek-Matuszek B, Gernand W, Nowakowski A, Solski J. Serum fibroblast growth factor 21 is predictive of combined cardiovascular morbidity and mortality in patients with type 2 diabetes at a relatively short-term follow-up. Diabetes Res Clin Pract. 2013;101:194–200.View ArticlePubMedGoogle Scholar
  41. Ong KL, Januszewski AS, O’Connell R, Jenkins AJ, Xu A, Sullivan DR, et al. The relationship of fibroblast growth factor 21 with cardiovascular outcome events in the Fenofibrate Intervention and Event Lowering in Diabetes study. Diabetologia. 2014; [Epub ahead of print]Google Scholar

Copyright

© Zhang et al.; licensee BioMed Central. 2015

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Advertisement