Gulick T, Pieper S J, Murphy M A, Lange L G, Schreiner G F
Department of Medicine, Jewish Hospital, St. Louis, MO.
Circulation. 1991 Jul;84(1):313-21. doi: 10.1161/01.cir.84.1.313.
Potentially reversible congestive heart failure accompanies disease states associated with an immune cell myocardial infiltrate such as cardiac allograft rejection and inflammatory myocarditis. We therefore examined the hypothesis that immune cells can produce noncytotoxic alterations in cardiac function.
A novel system to evaluate cultured cardiac myocyte contractility was developed using neonatal rat cardiocytes grown on human amniotic membrane segments. Spontaneous synchronous cell beating produced macroscopic distortion of these membranes. Movement of free-floating membranes anchored within a perfusion chamber was visualized under low-power microscopy and measured from recordings of the rhythmic displacement of membrane-adherent markers. Additions of graded concentrations of isoproterenol to the perfusate produced up to threefold increases in the initial contractile phase velocity (contractile index), with an EC50 of 10(-7) M. When the extracellular Ca2+ concentration was increased from 0.9 to 3.6 mM, 2.43-fold increases in this index occurred. Myocytes incubated for 72 hours in the presence of dilutions of medium conditioned by activated rat splenic macrophages and lymphocytes exhibited an isoproterenol contractile index inhibited by 62% compared with control cells. In contrast, responses of supernatant-exposed and control cells to increased extracellular Ca2+ concentrations were not significantly different. Parallel studies of increases in myocyte intracellular adenosine 3':5'-cyclic monophosphate concentrations in response to isoproterenol stimulation demonstrated correlative inhibition that was specific for exposure to medium conditioned by immune cells.
Thus, a new method of in vitro cardiac contractility assessment that has significant advantages over existing systems has been developed and characterized. This new method has enabled description of an inhibitor of cardiac contractile function produced by activated immune cells.
潜在可逆性充血性心力衰竭伴随着与免疫细胞心肌浸润相关的疾病状态，如心脏移植排斥反应和炎症性心肌炎。因此，我们检验了免疫细胞可产生心脏功能非细胞毒性改变的假说。
利用在人羊膜段上生长的新生大鼠心肌细胞，开发了一种评估培养心肌细胞收缩性的新系统。自发同步细胞搏动使这些膜产生宏观变形。在低倍显微镜下观察固定在灌注室内的自由漂浮膜的运动，并根据膜附着标记物的节律性位移记录进行测量。向灌注液中添加不同浓度的异丙肾上腺素，初始收缩期速度（收缩指数）最多可增加三倍，半数有效浓度（EC50）为10⁻⁷ M。当细胞外Ca²⁺浓度从0.9 mM增加到3.6 mM时，该指数增加2.43倍。在由活化的大鼠脾巨噬细胞和淋巴细胞条件培养基稀释液中孵育72小时的心肌细胞，与对照细胞相比，异丙肾上腺素收缩指数受到62%的抑制。相反，上清液处理组和对照组细胞对细胞外Ca²⁺浓度增加的反应无显著差异。对异丙肾上腺素刺激后心肌细胞内3':5'-环磷酸腺苷浓度增加的平行研究表明，存在与免疫细胞条件培养基暴露相关的特异性相关抑制。
因此，已开发并表征了一种体外心脏收缩性评估的新方法，该方法比现有系统具有显著优势。这种新方法能够描述活化免疫细胞产生的心脏收缩功能抑制剂。
