Expression of platelet membrane glycoprotein Ib/IX/V complex Sample analysis between type 2 diabetes mellitus patients and healthy people

Furong LU; Lin SHEN; You QIN; Wei SHI; Lan GAO; Jianguo LIU

ABSTRACT

BACKGROUND:

It has been proved that platelet activation is involved in the development of diabetic angiopathy. Glycoprotein (GP) Ib/IX/V complex is one of the main platelet membrane glycoproteins, and the receptor of both von Willebrand Factor and thrombin. It plays a key role in the process of platelet activation.

OBJECTIVE:

To observe the expression changes of GP Ib/IX/V complex and its component GP Ibα in patients with type 2 diabetes mellitus.

DESIGN:

Case-control study.

SETTING:

Department of Integrated Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.

PARTICIPANTS:

A total of 51 type 2 diabetic outpatients who visited Union Hospital were enrolled from December 2005 to January 2007. The diagnosis was based on the independent criteria from WHO in 1999. Of all the 51 patients, there were 23 females and 28 males, with a peripheral platelet count of over 50×109 L-1. All the subjects had no history of administrating drugs two weeks before the examination, which would potentially influence platelet count. According to disease controlling condition, the patients were assigned to well controlled patient (WCP) group (n = 25) and poorly controlled patient (PCP) group (n =26); and according to whether angiopathy was accompanied, diabetic patients were divided into vascular disease (VD) group (n =27) and non-vascular disease (NVD) group (n =24). Meanwhile 23 healthy subjects were enrolled as normal control group. Informed consents were obtained from subjects and their relatives. The experiments were approved by the ethical committee of Union Hospital.

METHODS:

Fasting venous blood was harvested from all the subjects' elbow on the early morning of visit day.①Biochemical

analysis:

Fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c) and fasting plasma insulin (FINS) was measured by the Clinical Chemistry Department in Union Hospital.② Measurement of platelet membrane GP Ib/IX/V complex and its component GP Ibα First, 3 mL cubital fasting blood was drawn from each subject and was anti-coagulated with 38 g/L natrium citricum. After that, all samples were fixed with 10 g/L paraform for 45 minutes. Then 50 μL well-fixed blood was added into the polystyrene tube, meanwhile 20 μL monoclonal antibody, such as CD42a-b-c-d and PE-labeled CD42b, was respectively mixed gently with the blood sample and incubated at room temperature in dark for 30 minutes. Next, 20 μL FITC-labeled rat IgG was mixed with the sample containing CD42a-b-c-d and incubated equally. In the end all blood samples were analyzed by FACS420 flow cytometry and the results were expressed as mean fluorescence intensity (MFI). ③ Platelet maximun aggregation rate (MAR) was detected according to reference.MAIN OUTCOME

MEASURES:

①Biochemical indicators;②The expressions of GP Ib/IX/V complex and GP Ibα;③Platelet MAR.

RESULTS:

Fifty-one patients with type 2 diabetes mellitus and twenty-three healthy subjects were all involved in the result analysis.①There were significant differences in FINS in WCP group and PCP group compared with normal controls (P ＜ 0.01). FPG and HbA1c were significantly higher in PCP group compared with normal control group and WCP group (P ＜ 0.01).②Expressions of GP Ib/IX/V complex and GP Ibα were significantly lower in WCP group and PCP group compared with normal control group (P ＜ 0.01), significantly lower in PCP group than in WCP group (P ＜ 0.05), and also significantly lower in VD group and NVD group compared with normal control group (P ＜ 0.01). Moreover the expression of GP Ibα in VD group and NVD group was significantly lower than that of normal control group (P ＜ 0.05), and it also significantly decreased in VD group compared with NVD group (P ＜ 0.05). MFI of GP Ib/IX/V complex had an obvious negative correlation with FBG, HbA1c and FINS (r =-0.634, -0.573, -0.649, P ＜ 0.05), and GP Ibα MFI was obviously negatively correlated with FBG and HbA1c (r =-0.602, -0.543, P ＜ 0.05).③Platelet MAR of diabetic patients were remarkably higher than in healthy subjects (t =-3.852, P ＜ 0.01). Platelet MAR in PCP and VD groups were respectively higher than those in WCP and NVD groups (P ＜ 0.05).

CONCLUSION:

Platelet activation exists in the early stage of type 2 diabetes mellitus without diabetic angiopathy, and is more obvious after diabetic angiopathy. There is a positive correlation between platelet activation and blood glucose. As a receptor of thrombin and von Willebrand Factor, GP Ib/IX/V complex may be involved in the development of diabetic angiopathy.