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A protective antiarrhythmic role of ursodeoxycholic acid in an in vitro rat model of the cholestatic fetal heart
Author(s) -
Miragoli Michele,
Kadir Siti H. Sheikh Abdul,
Sheppard Mary N.,
Salvarani Nicoló,
Virta Matilda,
Wells Sarah,
Lab Max J.,
Nikolaev Viacheslav O.,
Moshkov Alexey,
Hague William M.,
Rohr Stephan,
Williamson Catherine,
Gorelik Julia
Publication year - 2011
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.24492
Subject(s) - ursodeoxycholic acid , fetus , medicine , hypoxia (environmental) , depolarization , endocrinology , electrical conduction system of the heart , cardiac arrhythmia , cardiology , pregnancy , biology , chemistry , atrial fibrillation , electrocardiography , genetics , organic chemistry , oxygen
Intrahepatic cholestasis of pregnancy may be complicated by fetal arrhythmia, fetal hypoxia, preterm labor, and, in severe cases, intrauterine death. The precise etiology of fetal death is not known. However, taurocholate has been demonstrated to cause arrhythmia and abnormal calcium dynamics in cardiomyocytes. To identify the underlying reason for increased susceptibility of fetal cardiomyocytes to arrhythmia, we studied myofibroblasts (MFBs), which appear during structural remodeling of the adult diseased heart. In vitro , they depolarize rat cardiomyocytes via heterocellular gap junctional coupling. Recently, it has been hypothesized that ventricular MFBs might appear in the developing human heart, triggered by physiological fetal hypoxia. However, their presence in the fetal heart (FH) and their proarrhythmogenic effects have not been systematically characterized. Immunohistochemistry demonstrated that ventricular MFBs transiently appear in the human FH during gestation. We established two in vitro models of the maternal heart (MH) and FH, both exposed to increasing doses of taurocholate. The MH model consisted of confluent strands of rat cardiomyocytes, whereas for the FH model, we added cardiac MFBs on top of cardiomyocytes. Taurocholate in the FH model, but not in the MH model, slowed conduction velocity from 19 to 9 cm/s, induced early after depolarizations, and resulted in sustained re‐entrant arrhythmias. These arrhythmic events were prevented by ursodeoxycholic acid, which hyperpolarized MFB membrane potential by modulating potassium conductance. Conclusion: These results illustrate that the appearance of MFBs in the FH may contribute to arrhythmias. The above‐described mechanism represents a new therapeutic approach for cardiac arrhythmias at the level of MFB. (H EPATOLOGY 2011;)