Waltham M, Burnand K G, Collins M, Smith A
Academic Department of Surgery, St Thomas' Hospital, London, United Kingdom.
J Vasc Surg. 2000 Nov;32(5):988-96. doi: 10.1067/mva.2000.110882.
Resolution of venous thrombi is accompanied by an ingrowth of capillaries, which appears to be analogous to angiogenesis in other tissues. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are major regulators of angiogenesis. The aim of this study was to determine the temporal changes and the location of VEGF and bFGF expression in a rat model of venous thrombus resolution.
Thrombi were induced in the inferior venae cavae of rats by creating a stenosis to reduce blood flow by 80% to 90%. Thrombi, adjacent inferior vena cava wall, and systemic blood were collected at 1, 3, 7, 14, 21, and 28 days after thrombus generation (n = 9). Sham operations were performed (n = 5), and blood was collected at 1, 3, and 7 days. VEGF and bFGF were measured with specific immunoassays, and levels in tissues were expressed as picogram per milligram soluble protein. Tissues from two animals that were humanely killed 7 days after thrombus formation were prepared for histological examination. Immunohistochemistry was performed by the use of antibodies against VEGF, bFGF, and ED-1 (a monocyte/macrophage marker).
Laminated thrombi were reliably produced with a median weight at 1 day of 39 mg (range, 23-63 mg). There was a significant increase in thrombus VEGF concentration between 1 day (median, 247; range, 0-514) and 7 days (median, 556; range, 254-1741) (P =.02). There was no difference between the seventh day and subsequent days. There was a positive linear correlation between thrombus bFGF concentration and time (R = 0.74, P <.0001), with a more than 300-fold increase in bFGF concentration over the 28 days of the study. VEGF and bFGF concentrations in the adjacent vena caval wall did not change significantly with time. The serum VEGF was significantly raised at 1 day (median, 5520 pg/mL; range, 4040-7912 pg/mL) and 3 days (median, 3880 pg/mL; range, 2564-7232 pg/mL) compared with 7 days (median, 1790 pg/mL; range, 232-3228 pg/mL) (P <.0001). Similar changes in the serum VEGF also developed in the sham-operated animals. The serum bFGF (day 1 median, 15.5 pg/mL; range, 1-42 pg/mL) did not change with time. Immunohistochemistry showed that the VEGF antigen was localized to monocytes, endothelial cells, and spindle-shaped cells within the thrombus. The bFGF antigen was localized to mononuclear cells and spindle-shaped cells and was also present in the extracellular matrix.
VEGF and bFGF are found in organizing thrombi and have characteristic temporal expression patterns, which suggest that they have a role in thrombus resolution. Augmenting angiogenic growth factor expression may enhance thrombus recanalization, thus reducing long-term complications.
静脉血栓溶解过程伴随着毛细血管长入，这似乎类似于其他组织中的血管生成。血管内皮生长因子（VEGF）和碱性成纤维细胞生长因子（bFGF）是血管生成的主要调节因子。本研究的目的是确定在大鼠静脉血栓溶解模型中VEGF和bFGF表达的时间变化及位置。
通过造成狭窄使大鼠下腔静脉血流减少80%至90%来诱导血栓形成。在血栓形成后1、3、7、14、21和28天收集血栓、相邻的下腔静脉壁及全身血液（n = 9）。进行假手术（n = 5），并在1、3和7天收集血液。用特异性免疫测定法检测VEGF和bFGF，组织中的水平以皮克每毫克可溶性蛋白表示。对血栓形成7天后人道处死的两只动物的组织进行组织学检查。使用抗VEGF、bFGF和ED-1（单核细胞/巨噬细胞标志物）的抗体进行免疫组织化学分析。
成功产生了分层血栓，第1天的中位重量为39毫克（范围为23 - 63毫克）。血栓VEGF浓度在第1天（中位值，247；范围，0 - 514）和第7天（中位值，556；范围，254 - 1741）之间显著增加（P = 0.02）。第7天与随后几天之间无差异。血栓bFGF浓度与时间呈正线性相关（R = 0.74，P < 0.0001），在研究的28天内bFGF浓度增加超过300倍。相邻腔静脉壁中的VEGF和bFGF浓度随时间无显著变化。与第7天（中位值，1790 pg/mL；范围，232 - 3228 pg/mL）相比，血清VEGF在第1天（中位值，5520 pg/mL；范围，4040 - 7912 pg/mL）和第3天（中位值，3880 pg/mL；范围，2564 - 7232 pg/mL）显著升高（P < 0.0001）。假手术动物的血清VEGF也出现类似变化。血清bFGF（第1天中位值，15.5 pg/mL；范围，1 - 42 pg/mL）随时间无变化。免疫组织化学显示，VEGF抗原定位于血栓内的单核细胞、内皮细胞和梭形细胞。bFGF抗原定位于单核细胞和梭形细胞，也存在于细胞外基质中。
在机化血栓中发现了VEGF和bFGF，且它们具有特征性的时间表达模式，这表明它们在血栓溶解中起作用。增加血管生成生长因子的表达可能会增强血栓再通，从而减少长期并发症。
