Friday, April 17, 2009

Friday April 17, 2009 (pediatric pearl)
Altered zinc homeostasis in septic shock

Intact zinc homeostasis must be present for normal function of the immune system, oxidative stress responses, neurocognitive function, and growth and development.

Metallothioneins are cysteine-rich, metal-binding proteins involved in the homeostasis of zinc transcription is strongly down-regulated in the setting of zinc deficiency, but is up-regulated with inflammation, metals, and administration of exogenous glucocorticoids

Plasma zinc concentrations are low in critically ill children.

A correlation between zinc levels and expression of some metallothionein isoforms was observed on day 1, whereas there was no correlation between zinc levels and measures of inflammation such as CRP and IL-6 on day 1. However, by day 3, this trend had reversed itself, such that the correlation with MT levels was no longer present, but plasma zinc was associated with CRP and IL-6 levels.

Also, by day 3 there was a correlation between plasma zinc levels and the degree of organ failure.

It is thought that that enhanced metallothionein expression early in acute stress and the associated decline in plasma zinc contribute to the subsequent inflammatory response and the risk of organ failure in critically ill children.



References: Click to get abstract

1. Genome-level expression profiles in pediatric septic shock indicate a role for altered zinc homeostasis in poor outcome - Physiol. Genomics 30: 146-155, 2007. First published March 20, 2007
2.
Zinc homeostasis in pediatric critical illness- Pediatric Critical Care Medicine. 10(1):29-34, January 2009