Circulating anti-inflammatory adipokines High Molecular Weight Adiponectin and Zinc-α2-glycoprotein (ZAG) are inhibited in early sepsis, but increase with clinical recovery: a pilot study

BACKGROUND Adipose tissue has been identified as an endocrine organ secreting adipokines involved in metabolic and inflammatory pathways. Adiponectin, an anti-inflammatory adipokine, is reduced in sepsis. High Molecular Weight (HMW) adiponectin, the biologically most relevant molecule, has been investigated very little in human sepsis. Zinc-alpha2-glycoprotein (ZAG) is a novel adipokine and its expression in adipose tissue is positively correlated with adiponectin expression. It is not yet known whether ZAG has a role in sepsis. In this study we assessed levels of HMW adiponectin and ZAG during different stages of sepsis. METHODS A prospective observational pilot study was carried out on 21 septic patients. Serum samples were taken on day 1 and 2 post ICU admission and on day of discharge. Samples were analysed for total and HMW adiponectin, HMW/total adiponectin ratio, and ZAG. Results were correlated with clinical and metabolic data. RESULTS There were no differences in total adiponectin, HMW adiponectin and ZAG plasma concentrations between day 1 (admission) and day 2 of the sepsis episode. Compared to admission, a significant increase in total and HMW adiponectin and ZAG was observed on the day of discharge when clinical improvement had been achieved. There was also an increase in the HMW/total adiponectin ratio at that time. CONCLUSIONS Our data demonstrate an increase in both HMW adiponectin and total adiponectin in patients who had clinically recovered from sepsis. The increase in HMW/total adiponectin ratio with improvement of the clinical condition suggests that HMW adiponectin may have a greater role in the inflammatory process and insulin resistance seen in sepsis. In this pilot study, we have also demonstrated a significant increase in ZAG in critically ill patients temporally related to recovery from sepsis.