Is there a role for probiotics in liver disease?

Intestinal microbiota plays an important role in health and disease. Alteration in its healthy homeostasis may result in the development of numerous liver disorders including complications of liver cirrhosis. On the other hand, restoration and modulation of intestinal flora through the use of probiotics is potentially an emerging therapeutic strategy. There is mounting evidence that probiotics are effective in the treatment of covert and overt hepatic encephalopathy, as well as in the prevention of recurrence of encephalopathy. The beneficial effect of probiotics also extends to liver function in cirrhosis, nonalcoholic fatty liver disease, and alcoholic liver disease. On the other hand, data associating probiotics and portal hypertension is scanty and conflicting. Probiotic therapy has also not been shown to prevent primary or secondary spontaneous bacterial peritonitis. Larger clinical studies are required before probiotics can be recommended as a treatment modality in liver diseases.

Screening for liver disease - are LFTs old hat?

The economic burden of end stage liver disease is set to increase due to the rising prevalence of cirrhosis secondary to alcohol, viral hepatitis and fatty liver disease. Screening for liver disease has been advocated, as most cases of cirrhosis are preventable with early interventions. Liver function tests (LFTs) are routinely used as a first line investigation to screen for liver diseases but can be normal despite significant underlying liver fibrosis, hepatitis, steatohepatitis or even cirrhosis. Their relationships are far from linear and with little predictive value in some cases. Newer non-invasive modalities are emerging but currently their roles are largely experimental. This review will discuss the role of serum biomarkers and imaging techniques as new modalities to screen for liver disease.

Vasopressin in liver disease--should we turn on or off?

Arginine vasopressin is a naturally occurring peptide with established physiological functions acting as a vasoconstrictor through V1 receptors or an aquagenic agent allowing free water retention through V2 receptors in the kidney. Portal haemodynamic changes of chronic liver disease are responsible for the lethal consequences of cirrhosis--bleeding oesophageal varices and hepatorenal syndrome. Increasing hepatic vascular resistance to blood flow coupled with central hypovolaemia and a hyperdynamic circulation driven by changes in nitric oxide responsiveness disturbs the normal circulatory physiology raising portal pressure. Vasopressin and its analogues are potent vasoconstrictors and can be utilised in the management of the complications of cirrhosis. Hyponatraemia is common in end stage liver disease due in part to sodium retention and a decreased free water clearance. Diuretic therapy often leads to a worsening of the sodium status and have little true effect on improving free water clearance. Recently a new class of drugs, V2 receptor antagonists, have been evaluated in chronic liver disease whereby increasing free water clearance they may reduce ascitic fluid development. This review addresses the pharmacology of both vasopressin agonists and antagonists, their clinical application and future potential roles in managing patients with acute on chronic liver failure.