Free Radicals and Biomarkers Related to the Diagnosis of Cardiorenal Syndrome

Abstract

The National Heart, Lung, and Blood Institute Working Group has postulated the cardiorenal syndrome (CRS) as an interaction between the kidneys and the cardiovascular system in which therapy to relieve congestive heart failure (HF) symptoms is limited by the further worsening renal function. CRS is classified from type I to V, taking into account the progression of the symptoms in terms of mechanisms, clinical conditions, and biomarkers. Experimental and clinical studies have shown the kidney as both a trigger and a target to sympathetic nervous system (SNS) overactivity. Renal damage and ischemia, activation of the renin angiotensin aldosterone system (RAAS), and dysfunction of nitric oxide (NO) system are associated with kidney adrenergic activation. Indeed, the imbalances of RAAS and/or SNS share an important common process in CRS: the activation and production of free radicals, especially reactive oxygen species (ROS). The present chapter addresses connections of the free radicals as potential biomarkers as the imbalances in the RAAS and the SNS are developed. Understanding the involvement of free radicals in CRS may bring knowledge to design studies in order to develop accurate pharmacological interventions.