Different effects of telmisartan and valsartan on human aortic vascular smooth muscle cell proliferation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Vascular smooth muscle cell proliferation is an important process in the development of atherosclerosis and is associated with other cellular processes in atherogenesis. Telmisartan is reported to have partial peroxisome proliferator-activated receptor (PPAR)-γ activating properties and has been referred to as selective PPAR modulators, but valsartan just blocks angiotensin II (AngII) type 1 (AT1) receptors. This study aimed to compare the different effects of telmisartan and valsartan on human aortic smooth muscle cells (HASMCs) proliferation.</p><p><b>METHODS</b>Ability of telmisartan and valsartan to inhibit proliferation of HASMCs was evaluated by the Cell Counting Kit-8 (CCK-8) in continuous cell culture. Whether the antiproliferative effects of telmisartan and valsartan depend on their effects on AngII receptors or activating the peroxisome PPAR-γ was also investigated in this study.</p><p><b>RESULTS</b>Telmisartan inhibited proliferation of HASMCs by 52.4% (P < 0.01) at the concentration of 25 µmol/L and the effect depended on the dose of telmisartan, but valsartan had little effect on HASMCs proliferation (P > 0.05) and no dose response. When tested in cells stimulated with AngII, telmisartan had the same inhibition of HASMCs by 59.2% (P < 0.05) and valsartan also inhibited it by 41.6% (P < 0.05). Telmisartan and valsartan had the same effect on down-regulating AT1 receptor expression and telmisartan was superior to valsartan up-regulating AngII type 2 (AT2) receptor expression. Antiproliferative effects of telmisartan were observed when HASMCs were treated with the PPAR-γ antagonist GW9662 but antiproliferative effects of the PPAR-γ activator pioglitazone were not observed.</p><p><b>CONCLUSIONS</b>Telmisartan, but not valsartan, inhibits HASMCs proliferation and has dose-dependent response without stimulation of AngII. AT2 receptor up-regulation of telmisartan contributes to its greater antiproliferative effects than valsartan. Its PPAR-γ activation does not play a critical role in inhibiting HASMCs proliferation.</p>

Hybrid retroviral vector with MCK enhancers inserted in LTR for stable and specific expression of human factor IX in skeletal muscle / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Retroviral vectors have been widely used to introduce foreign into various target cells in vitro, thus showing relatively high systemic delivery efficiency of various transgene products. The authors investigated the stability and efficiency of skeletal muscle-specific hybrid retroviral vectors in expression of human factor IX (FIX) in vitro and iv vivo.</p><p><b>METHODS</b>FIX cDNA in LIXSN vector was replaced with a FIX minigene containing splicing donor and splicing acceptor sequence of first intron of human FIX gene. Two copies of muscle creatine kinase enhancer (MCK, Me2) were inserted in forward or reverse orientation at NheI site of 3' long terminal repeat (LTR), resulting in two hybrid vectors, which were designated as LMe2IXm2SN(F) and LMe2IXm2SN(R), respectively. The vectors were tested in vitro and in vivo for stability and muscle-specificity of factor IX expression with SCID mice.</p><p><b>RESULTS</b>Muscle cells carrying vector with Me2 expressed significantly higher levels of FIX (up to 1800 ng/106.24 h) than those without Me2, thus suggesting that Me2 could specifically increase expression level of FIX in muscle cells. Myoblasts transduced with LMe2IXm2SN(R) produced much less FIX in vivo in SCID mice than LMe2IXm2SN(F). One or two copies of Me2 sequence were deleted in myoblasts transduced with LMe2IXm2SN(R) without changing the orientation of Me2.</p><p><b>CONCLUSIONS</b>LTR inserted with MCK enhancers can specifically increase human FIX expression in skeletal muscle cells in vitro and in vivo, and MCK enhancer should be positioned in the same orientation as that of LTR promoter.</p>

Preparation of rAAV2/hFIX and experimentally application to gene therapy for hemophilia B / 中华血液学杂志

<p><b>OBJECTIVE</b>To prepare the rAAV2/hFIX and evaluate the efficiency of the preparation on gene therapy of hemophilia B model mice.</p><p><b>METHODS</b>The rAAV-2/hFIX was prepared by "one helper virus-one vector cell line" strategy and transfected both BHK-21 and C2C12 cells in vitro. The hFIX antigen level in cell culture supernatant was assayed. The rAAV-2/hFIX was injected into muscles of hemophilia B model mice and assayed the serum hFIX levels, hFIX clotting activity, bleeding time, 5 min bleeding volume.</p><p><b>RESULTS</b>The hFIX antigen could be detected from 24 h till 120 h after BHK-21 and C2C12 cells were transfected with highest levels at 24 h reaching (51.0 +/- 6.5) ng/10(5) cells and (68.0 +/- 7.2) ng/10(5) cells, respectively. The rAAV2/hFIX injected mice could efficiently express hFIX and peaked at three weeks after injection, then slowly decreased but low level hFIX antigen was still detectable till 10 weeks after injection. There were significant differences between the high, middle and low dose groups of rAAV2/hFIX and the control group (P < 0.01), the plasma FIX clotting activities in the model mice were improved remarkably, bleeding time was greatly shortened and bleeding in 5 min was decreased. The hFIX expression level and FIX clotting activity of the high dose of rAAV2/hFIX group (1.6 x 10(13) v.g./kg) reached about (387.0 +/- 12.5) ng/ml plasma in contrast with the normal levels of (30.0 +/- 5.5)% at the third week after injection. No rAAV2 vector DNA was detected in the organs except for injected muscle tissue.</p><p><b>CONCLUSION</b>The rAAV2/hFIX transfected BHK-21 and C2C12 cells could efficiently express hFIX antigen and was of therapeutic effects for the hemophilia B model mice by intramuscularly injection.The results provide the basis for clinical trial of rAAV2 gene therapy for hemophilia B.</p>