Bancsi M J, Veltrop M H, Bertina R M, Thompson J
Department of Infectious Diseases, Leiden University Hospital, The Netherlands.
Infect Immun. 1996 Feb;64(2):448-51. doi: 10.1128/iai.64.2.448-451.1996.
A main feature in the pathogenesis of bacterial endocarditis is the activation of the coagulation system via the extrinsic pathway, resulting in the formation of infected endocardial vegetations. Earlier studies gave indirect evidence that monocytes play an important role in the procoagulant response during the course of the disease. In this study, we assessed the role of monocytes more directly. We compared weights and tissue factor activities (TFA) of endocardial vegetations of normal rabbits infected with Streptococcus sanguis with those of rabbits which were treated with the cytostatic drug etoposide (Vepesid; Bristol-Myers Squibb B.V.) to induce a selective monocytopenia. Furthermore, the importance of the presence of bacteria was determined through the influence of antibiotic treatment on TFA, vegetational weight, and infection of the vegetations. The TFA of the vegetations was measured chromogenically by monitoring the factor VII-dependent activation of factor X with an amidolytic assay for factor Xa. We found that the degree of infection and the weight of vegetations of rabbits treated with the cytostatic drug etoposide did not differ from that of untreated rabbits. Their TFA, however, was significantly lower than the TFA of vegetations of rabbits not treated with etoposide. We also found that, as with the monocytopenic rabbits, the weight of the vegetations was not reduced in penicillin G-treated rabbits. The degree of infection and TFA, however, were significantly lower. We conclude that monocytes indeed are involved in the activation of the coagulation system during the course of bacterial endocarditis and that the degree of infection is positively correlated to the TFA of the vegetations.
细菌性心内膜炎发病机制的一个主要特征是通过外源性途径激活凝血系统，导致感染性心内膜赘生物形成。早期研究间接证明，单核细胞在疾病过程中的促凝反应中起重要作用。在本研究中，我们更直接地评估了单核细胞的作用。我们比较了感染血链球菌的正常兔的心内膜赘生物的重量和组织因子活性（TFA）与用细胞抑制药物依托泊苷（Vepesid；百时美施贵宝公司）治疗以诱导选择性单核细胞减少的兔的心内膜赘生物的重量和组织因子活性。此外，通过抗生素治疗对TFA、赘生物重量和赘生物感染的影响来确定细菌存在的重要性。通过用针对因子Xa的酰胺水解测定法监测因子VII依赖的因子X激活，显色法测量赘生物的TFA。我们发现，用细胞抑制药物依托泊苷治疗的兔的感染程度和赘生物重量与未治疗的兔没有差异。然而，它们的TFA显著低于未用依托泊苷治疗的兔的赘生物的TFA。我们还发现，与单核细胞减少的兔一样，青霉素G治疗的兔的赘生物重量没有减轻。然而，感染程度和TFA显著降低。我们得出结论，单核细胞确实参与了细菌性心内膜炎过程中凝血系统的激活，并且感染程度与赘生物的TFA呈正相关。
