Effects of hypoxia-inducible factor inhibitor on expression of HIF-1alpha and VEGF and induction of apoptosis in leukemic cell lines / 中国实验血液学杂志

This study was purposed to investigate the effect of a hypoxia-inducible factor inhibitor (YC-1) on expression of hypoxia-inducible factor 1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) as well as induction of apoptosis in leukemic cell lines. RT-PCR was used to determine the levels of HIF-1alpha mRNA and VEGF mRNA in K562, U937 and Jurkat cells. After treatment of U937 cell with 4 micromol/L YC-1, cell apoptosis was assayed by DAPI staining under fluorescent microscope and flow cytometry with Annexin V-FITC/PI staining; the expression levels of HIF-1alpha mRNA and VEGF mRNA were measured with RT-PCR; the expression levels of HIF-1alpha, VEGF, BAX, BCL-2 and caspase-3 proteins were measured by Western blot. The results showed that HIF-1alpha mRNA and VEGF mRNA were expressed in all three leukemia cell lines. After treatment of U937 cell with 4 micromol/L YC-1 for 0, 8, 16 and 24 hours, the changes of morphologic features of U937 cells could be observed under fluorescent microscope and the apoptotic rates significantly increased in time-dependent manner, they were (4.87 +/- 0.70)%, (27.27 +/- 2.00)%, (51.53 +/- 2.81) and (60.5 +/- 3.20)% respectively, the expression levels of VEGF mRNA reduced, while the expression levels of HIF-1alpha mRNA had no obviously changes.Furthermore, the expression of HIF-1alpha, VEGF and BCL-2 decreased, while the expression of BAX and caspase-3 increased, the ratio of BAX/BCL-2 increased in time-dependent manner (r = 0.973, p < 0.01). It is concluded that HIF-1alpha mRNA and VEGF mRNA are all expressed in in K562, U937 and Jurkat cells, YC-1 has significant effect on down-regulating the protein expression of HIF-1alpha and VEGF, and induces the apoptosis in U937. The mechanism of apoptosis in leukemic cells may involve in up-regulating BAX/BCL-2 ratio and expression of protein caspase-3.

Gene expression in patients with myelodysplastic syndrome / 中国实验血液学杂志

This study was aimed to investigate the expression of c-FLIPL, c-FLIPS and DLK1 mRNA in the patients with myelodysplastic syndrome (MDS) and its clinical significance. The mRNA expression of c-FLIPL, c-FLIPS and DLK1 in bone marrow mononuclear cells (BMMNC) of 16 patients with MDS and 3 controls were detected by RT-PCR. The results indicated that the expression of DLK1 mRNA was up-regulated in MDS, including RA and RAEB, as compared with controls (p < 0.05). There was no significant difference in expression of DLK1 between RA and RAEB patients (p > 0.05); the expression of c-FLIPL mRNA both in RA and RAEB patients was higher than that in controls (p < 0.05). There was no significant difference in expression of c-FLIPL between RA and RAEB patients (p > 0.05); the expression of c-FLIPS mRNA was not significantly different between MDS patients and controls (p > 0.05), but its expression in RAEB patients was significantly higher as compared with RA patients and controls (p < 0.05). It is concluded that the mRNA expressions of DLK1, c-FLIPL and c-FLIPS in MDS patients are abnormal, some of which may be useful as an important indicator for the evaluation of development in MDS.

Effects of platelet-derived membrane microparticles on angiogenesis in chick chorioallantoic membranes / 中国实验血液学杂志

This study was purposed to investigate the angiogenesis effect of platelet-derived membrane microparticles (PMPs) in chick chorioallantoic membranes (CAM). Thrombin were adopted to activate the platelets and then PMPs were obtained. PMPs were isolated by high speed centrifugation. Flow cytometry (FCM) was adopted to evaluate the efficiency of thrombin to produce PMPs and BCA method was adopted to evaluate the content of PMPs. PMPs were put into CAM and the effects of PMPs on angiogenesis in CAM were observed. The results indicated that after incubation for 72 hours at the concentration of 80 microg/ml PMPs, the vessel nets in a 'spoked-wheel' pattern were shown around mixed fibrous filter membranes, number of vessel ramification was 112.5 +/- 11.31 and ratio of vessel area/CAM area was 6.19 +/- 1.29%, but there were not localized allantoic vessels developing in the control group, the number of vessel ramification and ratio of vessel area/CAM area in control group were 82.6 +/- 8.05 and 1.78 +/- 0.33 respectively, so there was significant difference between PMP and control groups. In above mentioned conditions, the number of vessel ramification and ratio of vessel area/CAM area in VEGF group were 128.4 +/- 10.02 and 7.44 +/- 1.36 respectively, so there was no difference between PMP and VEGF groups. It is concluded that PMPs show promotive effect on the formation of capillaries in chick chorioallantoic membranes.

Effects of platelet-derived membrane microparticles on the proliferation and apoptosis of human umbilical vein endothelial cells / 中国实验血液学杂志

This study was purposed to investigate the effects of platelet-derived membrane microparticles (PMP) on the proliferation and apoptosis of human umbilical vein endothelial cells (HUVEC). Different concentrations of thrombin were adopted to activate the platelets so as to release PMPs. Flow cytometry (FCM) was adopted to evaluate the efficiencies of different concentrations of thrombin to release PMPs. By using the HUVEC cultivated in vitro as vector, the effects of PMPs on the proliferation and apoptosis of HUVEC were investigated by MTT and FCM. The results showed that the efficiencies releasing PMPs from platelets activated by 2.0, 1.5, 1.0, 0.5 U/ml thrombin were 28.7, 47.7, 50.1 and 43.9% respectively; PMPs induced proliferation of HUVEC in a dose dependent manner. At the concentration of 40 microg/ml PMPs, the proliferation rate of HUVEC was 1.8 +/- 0.3 times as much as blank control, the proliferation rate in group of vascular endothelial growth factor was 1.9 +/- 0.5 times of as much as blank control, there was no statistic difference (p > 0.05). The PMPs inhibited HUVEC apoptosis. Compared with the apoptosis rate of control (9.4 +/- 0.5)%, apoptosis rate in PMP group (40 microg/ml) was (3.9 +/- 0.4)% (p < 0.05). The addition of VEGF (10 microl/ml) did not successfully prevented apoptosis of HUVEC with apoptosis rate of (8.0 +/- 0.8)%. It is concluded that platelets activated by 1 U/ml thrombin gets the best efficiency of PMP release, which stimulates proliferation of HUVEC and inhibits its apoptosis.

Cold storage of rabbit platelet suspension by adding uridine diphosphate galactose / 中国实验血液学杂志

This study was aimed to investigate the method to cold-store platelets with uridine diphosphate galactose (UDP-Gal). Rabbit heart blood was prepared for concentrated platelet suspension to which UDP-Gal was added, and then stored for ten days in 4 degrees C refrigerator. Thereafter, platelet count, mean platelet volume (MPV), platelet distributing width (PDW), platelet aggregation function, platelet activity to urge coagulation including PF3aT and APCT and apoptosis were determined. Meanwhile, survival time in vivo was tested after cold-stored rabbit platelets labeled with Cr51 were transfused into rabbits. The results showed that there was not significant difference for Plt count, MPV, PDW, PF3aT and APCT between UDP-Gal cold-stored platelet group and fresh platelet group (P > 0.05). On the contrary, platelet count decreased significantly, MPV, PDW jumped and PF3aT and APCT went down in cold control group as compared with fresh platelet group (P < 0.01). Apoptosis increased in UDP-Gal cold-stored platelet group as compared with fresh platelet group (P < 0.05), but was significantly lower than that in cold control group (P < 0.01). Although PagT (inducing reagent: C-PG) decreased, it could still be above 50% of fresh platelet. Survival time in rabbit in vivo was close between UDP-Gal cold-stored platelet group and fresh platelet group (P < 0.05). Survival rate in seventy-two hours after transfusion in the fresh platelet group, UDP-Gal cold-stored platelet group and cold control group was 57.5% +/- 7.2%, 50.3% +/- 6.3% and 0.1% +/- 0.5% respectively. It is concluded that the UDP-Gal can well protect cold-stored rabbit platelets and prolong the survival time of cold-stored platelets in vivo.

Platelet-derived microparticles stimulate proliferation of granulocyte-macrophage progenitor cells from umbilical cord blood / 中国实验血液学杂志

This study was aimed to investigate the effect of platelet-derived microparticles (PMP) on stimulating the proliferation of granulocyte-macrophage progenitors (CFU-GM) from umbilical cord blood. Different concentrations of thrombin were adopted to activate the platelets for releasing PMP. Flow cytometry was adopted to evaluate the efficiencies of different concentrations of thrombin to produce PMP. Umbilical cord blood mononuclear cells (MNC) were obtained from healthy donors and the MNC were isolated by Ficoll density gradient centrifugation. MNC were cultured in 2.7% methylcellulose containing different concentration of PMP and colonies were counted under an inverted microscope after 7 days. The result showed that the release rate of PMP activated by 2.0, 1.5, 1.0 and 0.5 U/ml thrombin were 28.7%, 47.7%, 50.1% and 43.9% respectively. The PMP enhanced colony formation in dose-dependent manner. The number of colonies per 2 x 10(5) MNCs in groups of PMP at different concentrations (10, 50 and 100 microg/ml) were 119.8 +/- 32.2,142.8 +/- 45.2 and 180.8 +/- 85.1 respectively. The number of colonies in the groups of PMP at 100 microg/ml and 50 microg/ml were statistically significant when compared with control group (103.0 +/- 24.8) (P < 0.05). The number of colonies per 2 x 10(5) MNC in the group of PMP (10 microg/ml) was 119.8 +/- 32.2 which was higher than that in control group, but there was no statistical significance between two groups. It is concluded that platelet activated with 1.0 U/ml thrombin can get the best release efficiency of PMP and PMP can enhance the proliferation of granulocyte-macrophage progenitor cells of umbilical cord blood.

Evaluation of the effects of glycosylation on in vivo survival of cold-storage human platelets by using rabbit model / 中国实验血液学杂志

To study the effects of glycosylation on survival of cold-storage human platelets by using rabbit model. (51)Cr-labeling platelets were used to detect the platelet storage survival. The human platelets (2.0 x 10(12)/L) treated with 5 g/L uridine diphosphate galactose (UDP-Gal) were stored in 4 degrees C refrigeratory up to 10 days. The survival of human platelets in rabbits whose reticuloendothelial system was inhibited by the administration of ethyl palmitate was monitored in blood drawn at various times after the platelet transfusion. The results showed that the survival rate of platelets was significantly increased in cold-storage human platelets by UDP-Gal treatment. The survival rates of platelets at 2 hours after transfusion into rabbits in groups of fresh platelets group, UDP-Gal + cold platelets group and cold platelets group were (68.9 +/- 8.5)%, (65.4 +/- 8.0)% and (5.0 +/- 2.6)%, respectively. Compared with cold platelets group, significant differences were seen among all groups (P < 0.01). UDP-Gal + cold platelets group had no significant differences compared with fresh platelets group (P > 0.05). It is concluded that UDG-Gal can provide the protective effect on cold-storage human platelets and prolong the survival time of refrigerated human platelets in rabbit model.