Leukocyte infiltration and cross-talk with cardiomyocytes exploit intracellular stress pathways in dilated cardiomyopathy of idiopathic origin.

BACKGROUND AND OBJECTIVE

Dilated cardiomyopathy (DCM) is a prevalent form of heart failure results in dilation and disruption of heart. Most strikingly a majority of the DCM cases do not have any identified etiology, hence known as idiopathic DCM (IDCM). Our study aimed to investigate the cross-talk between leukocytes and cardiomyocytes in terms of cardiac inflammation and stress response in IDCM.

METHODS

60 IDCM patients and 60 age and sex matched healthy volunteers were recruited in this study based on the New York Heart Association (NYHA) guidelines. Their echocardiographic and biochemical markers were assessed and PBMCs were analyzed for leukocyte migration and inflammation. Also C2C12 myocyte cells were cultured with LPS-activated RAW264.7 monocytes to investigate the cross-talk between them.

RESULTS

Left ventricular (LV) dysfunction was evident in the IDCM patients which were correlated with their physical discomfort level according to NYHA classification. Their serum levels of IL-1β and TNF-α (≈ 20 pg/ml) were found to be very high along with hs-CRP and IL-2. Elevated levels of ROCK, SMA and ICAM-1 proteins indicated activation and migration of the leukocytes. During monocyte-myocyte co-culture, robust diapedesis was observed in the cultured macrophage cells towards myocytes through the transwell pores (8 µM) in presence of IL-1β and TNF-α causing ER stress and cell death in the myocytes. Inhibition of this migration or by alleviating ER stress inhibits leukocyte recruitment and ensures protection to the myocytes.

CONCLUSION

The present study showed that alleviating cellular stress and managing leukocyte migration promotes protection to the heart.