Wilde N T, Burgess R, Keenan D J, Lucas G S
University Department of Haematology, Manchester Royal Infirmary.
Br J Haematol. 1997 Aug;98(2):322-7. doi: 10.1046/j.1365-2141.1997.2373055.x.
Megakaryocytes (Mks) are found in the lungs and the blood stream as well as in the bone marrow. We modified a whole blood filtration method for Mks by immunostaining for CD61 using biotin streptavidin, and used this technique to study Mks and their morphology in the central venous and arterial circulations before, during and after cardiopulmonary bypass (CPB) in haematologically normal patients undergoing routine cardiac surgery. Blood samples were taken immediately after the insertion of central venous (V) and arterial (A) catheters and after thoracotomy, immediately before bypass. Further samples were taken after 60-90 min on-CPB and 180-240 min post-bypass. In comparison with the steady state before bypass, circulating Mk levels in blood on bypass increased dramatically, from (V) 10.93 +/- 3.94/ml (mean +/- SD) to 36.48 +/- 11.52/ml and from (A) 8.37 +/- 4.39/ml to 38.65 +/- 20.68/ml. This effect was still present, to a lesser extent, 180-240 min post-bypass. Circulating levels of Mks were consistently lower in the arterial circulation than in the venous circulation off bypass, but levels in the two circulations were comparable during CPB, confirming previous suggestions that the lungs are net removers of Mks from the circulation. Type 4 Mks, the largest and most normal morphologically, were rarely seen in arterial blood, but increased significantly during CPB, indicating that the lungs selectively remove large Mks. The lungs appear to play an active role in the regulation of Mk levels. This is lost during CPB and despite the extracorporeal 40 microm arterial line filter, large Mks enter the systemic circulation. More effective extracorporeal filtration of large Mks might reduce the neurological impairment seen in some patients who have undergone CPB.
巨核细胞（Mks）存在于肺、血流以及骨髓中。我们通过使用生物素链霉亲和素对CD61进行免疫染色，改良了一种用于分离巨核细胞的全血过滤方法，并运用该技术研究了接受常规心脏手术的血液学正常患者在体外循环（CPB）前、期间和之后中央静脉和动脉循环中的巨核细胞及其形态。在插入中心静脉（V）和动脉（A）导管后以及开胸后、体外循环前立即采集血样。在体外循环60 - 90分钟后和体外循环后180 - 240分钟采集更多血样。与体外循环前的稳态相比，体外循环时血液中循环的巨核细胞水平显著增加，从（V）10.93±3.94/毫升（平均值±标准差）增至36.48±11.52/毫升，从（A）8.37±4.39/毫升增至38.65±20.68/毫升。这种效应在体外循环后180 - 240分钟时仍在较小程度上存在。在体外循环前，动脉循环中巨核细胞的循环水平始终低于静脉循环，但在体外循环期间两个循环中的水平相当，这证实了先前的观点，即肺是循环中巨核细胞的净清除器官。形态最大且最正常的4型巨核细胞在动脉血中很少见，但在体外循环期间显著增加，表明肺选择性地清除大型巨核细胞。肺似乎在巨核细胞水平的调节中发挥着积极作用。这在体外循环期间丧失，并且尽管有体外40微米动脉管路过滤器，大型巨核细胞仍进入体循环。对大型巨核细胞进行更有效的体外过滤可能会减少一些接受体外循环患者出现的神经功能损害。
