Contrast Induced Acute Kidney Injury (CI- AKI) - Myths and Realities.

Contrast Induced Acute Kidney Injury (CI-AKI) is one of the most common causes of acute kidney injury in hospitalized patients. These days, contrast agents are widely being used in both cardiology and radiology procedures. Old age, history of diabetes, heart failure, proteinuria and low blood pressure are some important risk factors in the pathogenesis of CI-AKI. Apart from risk stratification and the use of low and iso-osmolar contrast agents, intravenous fluid hydration with crystalloids is the only recommended strategy for the prevention of CI-AKI. Agents like N-acetylcysteine (NAC), atrial natriuretic peptide, ascorbic acid, theophylline, and fenoldopam have failed to show any proven beneficial role in the prevention of CI-AKI. Though hemodialysis is still being perceived by many clinicians as the modality for contrast removal but prophylactic hemodialysis is now not recommended for the prevention of CI-AKI.

Complement activation in the tubulointerstitium: AKI, CKD, and in between.

Complement activation is actively regulated to prevent injudicious activation, such as on peritubular endothelia and basolateral aspects of tubules. Miao et al. studied mice in which the key complement regulator, Crry, was deleted from tubular cells. This lacked functional consequence in unmanipulated animals. Yet, following ischemia-reperfusion, there was greater injury due to alternative pathway activation of C5. When the balance between complement activation and regulation is tipped towards the former, pathologic complement activation can ensue.