The obesity paradox and acute kidney injury: beneficial effects of hyper-inflammation?

Sebastian Hafner,Uwe Knippschild,Andreas Hillenbrand,Peter Radermacher

doi:10.1186/cc13152

Sebastian Hafner, Uwe Knippschild + Show 2 more

Open Access

https://doi.org/10.1186/cc13152

Copy DOI

Journal: Critical Care	Publication Date: Jan 1, 2013
Citations: 33	License type: cc-by

Affiliation: University Hospital Ulm

Abstract

In the general population, obesity is associated with an increased mortality risk, whereas several epidemiological studies demonstrated a protective effect of obesity in critically ill patients. In this context, Sleeman and colleagues investigated the effects of obesity on kidney function in a well-established porcine model of cardiopulmonary bypass. The authors confirm literature data that obesity per se is associated with a chronic hyper-inflammatory status. Nevertheless, obese swine undergoing the surgical procedure presented with attenuated kidney dysfunction and tissue apoptosis. The authors suggest that the chronic inflammation causes pre-conditioning against excessive acute hyper-inflammation. The authors have to be commended for using a long-term, clinically relevant model that, moreover, addresses a variety of putative mechanisms. The study is discussed in the context of the controversial findings that, in contrast to the existing literature on improved survival, most studies available suggest a higher incidence and severity of acute kidney injury in obese patients when compared with lean controls.

Highlights

In the general population, obesity is associated with an increased mortality risk, whereas several epidemiological studies demonstrated a protective effect of obesity in critically ill patients
The cardiopulmonary bypass (CPB)-related increase in endothelin and isoform of the nitric oxide synthase (iNOS) expression in lean swine was attenuated in obese animals
Beneficial effects of pre-procedural hyper-inflammation may be outweighed by an excess hyper-inflammatory response during circulatory depression; Duburcq and colleagues [12] reported that endotoxin caused a more pronounced cardio-circulatory depression in obese swine than in lean controls, and this depression coincided with more severe lactic acidosis, coagulopathy, and twofold proinflammatory cytokine blood levels

Summary

Introduction

Obesity is associated with an increased mortality risk, whereas several epidemiological studies demonstrated a protective effect of obesity in critically ill patients. In a recent issue of Critical Care, Sleeman and colleagues [1] reported on the effects of obesity on kidney inflammation and function in swine undergoing cardiopulmonary bypass (CPB). The main findings were that (i) CPB per se impaired kidney function, and (ii) pre-existing obesity attenuated kidney dysfunction on the day after the intervention.

Results

Conclusion