Differential Effects of Central and Peripheral Fat Tissues on the Delayed Rectifier K⁺ Outward Currents in Cardiac Myocytes

Abstract

Objectives: The amount of fat tissue is associated with an increasing incidence of cardiac arrhythmias. The purpose of this study was to investigate effects of adipocytokines from different body fat on delayed rectifier K⁺ outward currents (I_K). Methods: H9c2 cells were treated with adipocytokine-free medium (the Adipo-free group) and with adipocytokines from epicardial (central fat group) and limb (peripheral fat group) rat fat tissues. I_K, as well as expressions of Kv2.1 and Kv2.1 mRNA in H9c2 cells, were measured and compared between different groups. Results: I_K measured in H9c2 cells immediately after treatment with adipocytokines were not significantly different from those treated with adipocytokine-free medium. After H9c2 cells were treated with adipocytokines for 18 h, I_K were significantly decreased in the peripheral and central fat groups in comparison with the Adipo-free group. Compared with the peripheral fat group, I_K were more significantly decreased in the central fat group. Expressions of Kv2.1 and Kv2.1 mRNA in H9c2 cells were not significantly different among the three groups. Conclusions: Adipocytokines significantly decreased I_K in H9c2 cells, and I_K was more prominently decreased by adipocytokines from epicardial fat than from limb fat tissues. The decrease in I_K by adipocytokines may partially contribute to the mechanisms of arrhythmogenesis by fat tissues.

Peripheral fat distribution versus waist circumference for predicting mortality in metabolic syndrome

“…Another study also revealed that a larger leg fat mass was associated with lower glucose levels, including fasting and postprandial glucose, particularly in women . Additionally, Lee and colleagues found that the amount of fat tissue in the central fat was associated with increased incidence of cardiac arrhythmias, compared with the PF group . These study results might provide some information for us to explain why PF plays a protective role in cardiovascular mortality.…”

Pericardial Fat Is Associated With the Risk of Ventricular Arrhythmia in Asian Patients

“…Previous study showed that cardiac adipocytokines significantly decreased the membrane potential of delayed rectifier K + outward currents. 24 Some distinctive electrophysiological effects of pericardial fat could be considered for the pathogenesis of ventricular arrhythmia. In this study, we found that pericardial fat was significantly associated with the occurrence of VPBs.…”

Adipocytokines modulate ionic currents – A key to lipotoxicity potentiated cardiac arrhythmia

“…Lee et al investigated the effects of adipocytokines from different body fats on delayed rectifier K + outward currents ( I Kr ) in cardiomyocytes [2]. In their study, H9c2 cells were treated with adipocytokine‐free medium (the Adipo‐free group), and with adipocytokines from rat epicardial (central fat group) or limb (peripheral fat group) fat tissues.…”