Effects of astaxanthin on blood coagulation, fibrinolysis and platelet aggregation in hyperlipidemic rats.

CONTEXT: Astaxanthin (ASTX) is a xanthophyll carotenoid that reduces hemostasis in hyperlipidemic organisms. Its antihemostatic mechanisms remain unclear. OBJECTIVE: The effects of ASTX on coagulation, the fibrinolytic system and platelet aggregation were investigated in hyperlipidemic rats. MATERIALS AND METHODS: Different doses of ASTX (5, 10 and 30 mg/kg/day, p.o.) were administered for four weeks to high-fat diet-induced hyperlipidemic rats. Serum lipid and lipoprotein levels were measured with an automatic biochemical analyzer. The prothrombin time (PT), activated partial thromboplastin time (APTT) and maximum platelet aggregation rate (MAR) were determined by a coagulation analyzer. The activities of the tissue-type plasminogen activator (t-PA), type-1 plasminogen activator inhibitor (PAI-1) and endothelial nitric oxide synthase (eNOS), as well as the levels of thromboxane B(2) [TXB(2)], 6-keto prostaglandin F(1α) [6-keto-PGF(1α)] and platelet granule membrane protein (GMP-140), were measured with enzyme-linked immunosorbent assay kits. Gene and protein expression levels were analyzed by reverse transcriptase polymerase chain reaction and Western blot, respectively. RESULTS: ASTX (30 mg/kg) treatment in hyperlipidemic rats reduced serum TG (0.58 ± 0.14 versus 1.12 ± 0.24 mmol/L), serum TC (1.77 ± 0.22 versus 2.24 ± 0.21 mmol/L), serum LDL-C (1.13 ± 0.32 versus 2.04 ± 0.48 mmol/L), serum MDA (69%), plasma MAR (55%), serum TXB2/6-keto-PGF1α (34%) and serum GMP-140 levels (25%), plasma PAI-1 activity (48%) and downregulated the mRNA (33%) and protein (23%) expression of aorta eNOS, the mRNA (79%) and protein (72%) expression levels of aorta PAI-1. However, ASTX (30 mg/kg/d) treatment increased serum SOD activity (2.1 fold), serum GPx activity (1.8 fold), plasma PT (1.3 fold), plasma APTT (1.7 fold), serum NO (1.4-fold), serum 6-keto-PGF1α (1.3 fold). CONCLUSIONS: ASTX reduced blood coagulation and platelet aggregation and promoted fibrinolytic activity in hyperlipidemic rats. These activities were closely correlated with ASTX, maintaining the balance of t-PA/PAI-1, NO/ROS and TXA2/PGI2 in vivo.

Protective effect of Lycium barbarum on doxorubicin-induced cardiotoxicity.

The objective of this work was to explore the hypothesis that Lycium barbarum (LB) may be protective against doxorubicin (DOX)-induced cardiotoxicity through antioxidant-mediated mechanisms. Male SD rats were treated with distilled water or a water extract of LB (25 mg/kg, p.o.) daily and saline or DOX (5 mg/kg, i.v.) weekly for 3 weeks. Mortality, general condition and body weight were observed during the experiment. DOX-induced cardiotoxicity was assessed by electrocardiograph, heart antioxidant activity, serum levels of creatine kinase (CK) and aspartate aminotransferase (AST) and histopathological change. The DOX group showed higher mortality (38%) and worse physical characterization. Moreover, DOX caused myocardial injury manifested by arrhythmias and conduction abnormalities in ECG (increased QT and ST intervals and ST elevation), a decrease of heart antioxidant activity, an increase of serum CK and AST, as well as myocardial lesions. Pretreatment with LB significantly prevented the loss of myofibrils and improved the heart function of the DOX-treated rats as evidenced from lower mortality (13%), normalization of antioxidative activity and serum AST and CK, as well as improving arrhythmias and conduction abnormalities. These results suggested that LB elicited a typical cardioprotective effect on DOX-related oxidative stress. Furthermore, in vitro cytotoxic study showed the antitumor activity of DOX was not compromised by LB. It is possible that LB could be used as a useful adjunct in combination with DOX chemotherapy.

[Purification of human VLDL apolipoproteins by middle pressure liquid chromatography].

OBJECTIVE: To purify human VLDL apolipoproteins by middle-pressure liquid chromatography. METHODS: Human VLDLs were isolated by one step density ultracentrifugation. Delipided human VLDL was separated by Sephacryl S-200 molecular sieve chromatography. ApoE was purified by heparin Sepharose CL-6B affinity chromatography. ApoC I ,C II and C III were purified from apoC. fraction by DEAE-Sephacel ion exchange chromatography: RESULTS: Purified apoE, apoC I, apoC II and apoC III were obtained. SDS-PAGE and immunodiffusion tests indicated the isolated proteins were pure. CONCLUSION: We have established a purification procedure for human VLDL apolipoproteins with highly efficiency and simplicity by MPLC.

Plasma very-low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein oxidative modification induces procoagulant profiles in endogenous hypertriglyceridemia.

This study was to investigate whether oxidatively modified lipoproteins were associated with changes of pro- and anticoagulant profiles in hypertriglyceridemic subjects. Plasma VLDL, LDL, and HDL were isolated with the one-step density gradient ultracentrifugation method. The oxidation of the lipoproteins was identified. Prothrombin time (PT) and activated partial thrombplastin time (APTT), tissue plasminogen activator and plasminogen activator inhibitor-1, and platelet aggregation rate were determined with a reaction system consisting of mixed fresh normal plasma, in endogenous hypertriglyceridemic (HTG) patients, in in vitro modified lipoproteins from a normolipidemic donor, and in experimental rats. The results indicated that oxVLDL, oxLDL, and oxHDL occurred in the plasma of HTG patients. Compared with the control group, PT and APTT, incubated with plasma VLDL, LDL, or HDL from HTG patients, respectively, were significantly reduced, while platelet maximal aggregation rates were significantly higher (P < 0.05-0.01). Similar procoagulant profiles were observed in in vitro modified lipoprotein components and in rats with intrinsic hypertriglyceridemia as well. These results support our previous finding that LDL, VLDL, and HDL were all oxidatively modified in vivo in the subjects with HTG, and suggest that procoagulation state may result from the abnormal plasma lipoprotein oxidative modification in vivo.

[Effects of plasma very low density lipoprotein, low density lipoprotein and high density lipoprotein on platelet aggregation in endogenous hypertriglyceridemia].

OBJECTIVE: To study whether plasma very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein (HDL) were oxidatively modified in endogenous hypertriglyceridemia (HTG) and to investigate the effects of HTG VLDL, LDL and HDL on platelet aggregation in vitro. METHODS: Blood samples were taken from 21 patients with endogenous triglyceridemia and 21 normal healthy subjects; these two groups were similar in respect to age and sex. Their plasma VLDL, LDL and HDL were isolated by density gradient ultracentrifugation method, and plasma triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDLC) were measured by enzyme method. The oxidative modification of LDL, VLDL and HDL was identified by agarose gel relative electrophoretic mobility (REM), absorbance at 234 nm (A234) and fluorescence of thiobarbituric acid reaction substances (TBARS). With the reaction system that consisted of mixed fresh normal plasma, platelet aggregation was induced by adenosine diphosphate (ADP), and the platelet maximal aggregation rate (MAR) was recorded on a 4-channel light aggregometer. RESULTS: The plasma TG, TBARS levels in HTG group were 1.6 and 0.4 times over those of the control group respectively (P < 0.01). The plasma HDLC in HTG group was 32% lower than those of the control group (P < 0.01). REM, A234 and TBARS of VLDL, LDL and HDL in HTG group were significantly higher than those in the control group (P < 0.01). MAR of VLDL, LDL and HDL in HTG group were significantly higher than those in the control group (P < 0.05). The correlation analysis indicated that REM, A234 and TBARS of LDL and HDL in HTG group were positively correlated with MAR (P < 0.01). CONCLUSION: The above data indicated that oxidative modification of plasma VLDL, LDL, HDL did occur in endogenous hypertriglyceridemia in vivo, and VLDL, LDL and HDL enhanced platelet aggregation in vitro.

[Plasma haemostatic and fibrinolytic activities and their relationship to levels of serum lipids and apolipoproteins in endogenous hypertriglyceridemic patients].

OBJECTIVE: To investigate the changes of plasma haemostatic and fibrinolytic activities and their relationship to serum lipids and apolipoproteins levels in endogenous hypertriglyceridemic patients. METHODS: We determined the plasma prothrombin time(PT), activated partial thromplastin time(APTT), activity of tissue-type plasminogen activator(t-PA), activity of plasminogen activator inhibitor-1 (PAI-1) and fibrinogen(Fg) level of 24 endogenous hyper-triglyceridemic patients and 34 healthy controls, and observed their relationship to serum lipids and apolipoproteins. RESULTS: The PT and APTT of patients with hypertriglyceridemia were obviously shorter than those of control subjects (P < 0.01, P < 0.05); PAI-1 of patients was significant higher than that of control group (P < 0.01); there was no statistically significant difference in t-PAI-1: a between the control subjects and the hypertriglyceridemic patients; the levels of Fg in patients was 27% higher than that in healthy control (P < 0.01). The correlation analysis indicated that PT was significantly associated with the levels of plasma HDL-C (r = 0.445, P < 0.01), and inversely associated with the levels of plasma TG, apoC III, BG and BMI (r = -0.294, -0.320, -0.282, -0.272, P < 0.05); APTT was negatively correlated with serum TG and apoC III levels (r = -0.345, -0.320, P < 0.05); t-PA was negatively correlated with BG levels (r = -0.336, P < 0.01). PAI-1 and Fg levels were strongly correlated with serum TG, apoC II, C III and E levels (r = 0.400, 0.408, 0.497, 0.454, P < 0.01 and r = 0.642, 0.581, 0.673, 0.304, P < 0.01, respectively), and negatively correlated with HDL-C (r = -0.366, -0.524, P < 0.01). CONCLUSION: Increasing of coagulating activity and decreasing of fibrinolytic activity in hypertriglyceridemic patients were significantly associated with serum lipids and apolipoproteins levels.