Background & aims: Apoptosis regulates leucocyte response during bacterial infections. This study explored leucocyte apoptotic pathway in cirrhotic patients with or without infections or sepsis.
Methods: In cirrhotic patients with bacterial infection or sepsis, the expression of Caspase 9, Bcl-2 family proteins, which comprises pro-apoptotic molecules, such as Bax, and anti-apoptotic molecules, such as Bcl-2 and Bcl-xL, were measured in peripheral lymphocytes and granulocytes. Regulatory microRNAs MIR-15 and MIR-16 were also measured.
Results: This study enrolled 80 patients with cirrhosis, of whom 28 had no evidence of infections, 32 had bacterial infections and 20 had sepsis; reference values were obtained from 10 age-matched healthy subjects. An over-expression of Caspase-9 and pro-apoptotic protein Bax was found in lymphocytes of cirrhotic patients with infection or sepsis as compared with non-infected cases (P = 0.05 and 0.0001, respectively), while anti-apoptotic proteins Bcl-2 and Bcl-xL were downregulated. In granulocytes, lowest expression of pro-apoptotic protein Bax occurred in septic patients, while in cirrhotics with infections anti-apoptotic Bcl-2 and Bcl-xL were upregulated. Eight patients died; the survivors had less derangements in Bax, Bcl-2 and BcL-xL expression than non-survivors. The pro-apoptotic miRNA, MIR-15 and MIR-16, were upregulated in cirrhotics with bacterial infections.
Conclusions: Overall, the data show in lymphocytes, and not in granulocytes, an activation of the pro-apoptotic pathway in cirrhotic patients with bacterial infections, which correlates with the severity of the infection and the outcome.
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.