Rogler G, Lackner K J, Schmitz G
Institut für Klinische Chemie und Laboratoriumsmedizin Universität Regensburg, FRG.
Basic Res Cardiol. 1995 Nov-Dec;90(6):443-50. doi: 10.1007/BF00788536.
The effects of mevalonate depletion on growth and cell cycle kinetics of porcine and human vascular smooth muscle cells (SMC) were studied by growth curves and flow cytometric determination of cell cycle distribution. Porcine and human SMC were growth arrested by serum depletion for 48 h. Subsequently, they were stimulated to maximal growth and DNA synthesis by addition of serum. There was a concentration dependent decrease in the proliferation of human and porcine SMC, when cells were incubated in the presence of fluvastatin, a new, fully synthetic HMGCoA-reductase inhibitor. The reduction of cell number was significant with 10(-5) M and 10(-4)M fluvastatin. The highest concentration induced cell loss after prolonged incubation (> 4 days). The G/S-phase transition of human and porcine vascular SMC was reduced to 50% of controls by 10(-4) M fluvastatin as revealed by cell cycle analysis. The effects of fluvastatin on growth kinetics and cell cycle distribution could be completely reversed by the addition of 1 mM mevalonolactone. This indicates that the inhibitory effect of fluvastatin is caused by the inhibition of HMGCoA-reductase and depletion of mevalonate rather than being unspecific. Addition of LDL to supply cholesterol failed to support cell growth and transition of smooth muscle cells from G(zero)/G1-phase to S-phase, even though LDL was taken up by the cells as shown by confocal fluorescence microscopy. Neither did the addition of squalene or cholesterol to the culture medium normalize cell growth. It is concluded that nonsterol products that are synthesized from mevalonate are necessary for growth of smooth muscle cells. HMGCoA-reductase inhibitors like fluvastatin block the synthesis of these nonsterol precursors in human and porcine vascular SMC in vitro and are therefore growth inhibitory.
通过生长曲线和细胞周期分布的流式细胞术测定，研究了甲羟戊酸耗竭对猪和人血管平滑肌细胞（SMC）生长及细胞周期动力学的影响。猪和人SMC通过血清剥夺生长停滞48小时。随后，通过添加血清刺激它们达到最大生长和DNA合成。当细胞在新型全合成HMGCoA还原酶抑制剂氟伐他汀存在下孵育时，人和猪SMC的增殖呈浓度依赖性降低。10⁻⁵ M和10⁻⁴ M氟伐他汀时细胞数量减少显著。最高浓度在长时间孵育（>4天）后导致细胞丢失。细胞周期分析显示，10⁻⁴ M氟伐他汀使人和猪血管SMC的G/S期转换降至对照的50%。添加1 mM甲羟戊酸内酯可完全逆转氟伐他汀对生长动力学和细胞周期分布的影响。这表明氟伐他汀的抑制作用是由HMGCoA还原酶抑制和甲羟戊酸耗竭引起的，而非非特异性的。添加低密度脂蛋白（LDL）以供应胆固醇未能支持细胞生长和平滑肌细胞从G₀/G₁期向S期的转换，尽管共聚焦荧光显微镜显示细胞摄取了LDL。向培养基中添加角鲨烯或胆固醇也未使细胞生长恢复正常。结论是，由甲羟戊酸合成的非甾醇产物是平滑肌细胞生长所必需的。像氟伐他汀这样的HMGCoA还原酶抑制剂在体外阻断人和猪血管SMC中这些非甾醇前体的合成，因此具有生长抑制作用。
