Cross talk between cytokines and renin-angiotensin in hypothalamic paraventricular nucleus in heart failure: role of nuclear factor-κB

Aims Nuclear factor-kappa B (NF-kB) is a potent inducer of pro-inflammatory cytokines (PIC) and oxidative stress in cardiovascular disease. In this study, we determined whether upregulation of NFkB in the hypothalamic paraventricular nucleus (PVN) contributed to neurohumoral excitation either directly, or via interaction with the renin–angiotensin system (RAS), in heart failure (HF). Methods and results Rats were implanted with intracerebroventricular (ICV) cannulae and subjected to coronary artery ligation, or sham surgery (SHAM). Subsequently, animals were ICV treated with the angiotensin type 1 receptor (AT1-R) antagonist losartan (LOS, 20 mg/h), or SN50 (2 mg/h), which inhibits nuclear translocation of NF-kB, or tempol (TEMP, 80 mg/h), a membrane-permeable superoxide scavenger, or vehicle for 4 weeks. HF induced a significant increase in the expression of AT1-R, PIC, and NAD(P)H oxidase genes and NF-kB p50 in the PVN and in plasma norepinephrine (NE) levels when compared with SHAM rats. In contrast, ICV LOS, SN50, or TEMP attenuated PIC, NF-kB p50, AT1-R and NAD(P)H oxidase genes in the PVN compared with vehicle-treated HF rats. Treatment with LOS, SN50, or TEMP also reduced plasma levels of NE, angiotensin II, and PIC, and decreased left ventricular end diastolic pressure. Conclusion These findings indicate that NF-kB mediates the cross-talk between RAS and PIC in the PVN in HF, and that superoxide stimulates more NF-kB in the PVN and contributes to neurohumoral excitation.