Rekhter M D, Gordon D
Department of Pathology, University of Michigan, Ann Arbor 48109-0602.
Circ Res. 1994 Sep;75(3):410-7. doi: 10.1161/01.res.75.3.410.
Previous studies have indicated the focal presence of growth factors and focal low levels of cell proliferation in human atherosclerotic plaques. Using human carotid plaques and an antibody to platelet-derived growth factor (PDGF)-A chain, we have begun to assess growth factor significance by spatially correlating growth factor gene expression with actual cell proliferation. Since PDGF is a mitogen for smooth muscle and related cells and since inflammatory cells (eg, macrophages) can also proliferate in these lesions, it was important to exclude inflammatory cell proliferation from this consideration. Therefore, we have used a triple immunolabeling approach, combining the above anti-PDGF-A chain antibody with an inflammatory cell cocktail (CD68+CD45 for monocyte/macrophages and lymphocytes) and adding an anti-proliferating cell nuclear antigen (PCNA) antibody to mark proliferating cells. In the carotid atherosclerotic plaques, PDGF immunostaining was distributed focally, preferentially in the fibrous cap and vascularized regions, and was present in two distinct patterns: cytoplasmic and diffuse extracellular staining. When we considered colocalization within the same cells, cytoplasmic PDGF-A staining did not appear to colocalize with inflammatory markers. PCNA nuclear staining combined with PDGF cytoplasmic staining of the same cell was detected extremely rarely. Considering colocalization within the same microscopic fields, PDGF-A staining was detected more frequently than noninflammatory PCNA positivity. Quantitative logistic regression analysis demonstrated that localization in vascularized regions and (independently) the presence of PDGF-A are good predictors of noninflammatory cell proliferation, within the same microscopic fields. Therefore, PDGF-A and other factors especially associated with vascularized regions may be involved in the regulation of mesenchymal cell proliferation in human atherosclerotic plaques.
先前的研究表明，人类动脉粥样硬化斑块中存在生长因子且细胞增殖水平局部较低。我们利用人类颈动脉斑块和抗血小板衍生生长因子（PDGF）-A链抗体，通过将生长因子基因表达与实际细胞增殖进行空间关联，开始评估生长因子的重要性。由于PDGF是平滑肌及相关细胞的有丝分裂原，且炎症细胞（如巨噬细胞）也可在这些病变中增殖，因此在本研究中排除炎症细胞增殖很重要。所以，我们采用了三重免疫标记方法，将上述抗PDGF-A链抗体与炎症细胞混合物（用于单核细胞/巨噬细胞和淋巴细胞的CD68+CD45）相结合，并添加抗增殖细胞核抗原（PCNA）抗体来标记增殖细胞。在颈动脉粥样硬化斑块中，PDGF免疫染色呈局灶性分布，优先分布于纤维帽和血管化区域，且呈现两种不同模式：细胞质染色和弥漫性细胞外染色。当我们考虑同一细胞内的共定位时，细胞质PDGF-A染色似乎与炎症标记物不共定位。同一细胞的PCNA细胞核染色与PDGF细胞质染色极少同时出现。考虑同一显微镜视野内的共定位情况，PDGF-A染色的检测频率高于非炎症性PCNA阳性。定量逻辑回归分析表明，在同一显微镜视野内，血管化区域的定位以及（独立地）PDGF-A的存在是非炎症性细胞增殖的良好预测指标。因此，PDGF-A和其他与血管化区域特别相关的因子可能参与了人类动脉粥样硬化斑块中间充质细胞增殖的调控。
