serum melatonin level and cognitive dysfunction in patients with liver cirrhosis

ABSTRACT

The mechanism of hepatic encephalopathy are uncertain despite extensive studies. Recently, many studies have been done to find out the role of the melatonin hormone and its relation to many diseases especially liver cirrhosis. The present study was designed to detect the change in serum melatonin level in patients with liver cirrhosis and its correlation with the clinical status of the patients and their cognitive functions. Seventeen patients with liver cirrhosis and 12 matched healthy controls were recruited in the study. They were subjected to clinical examination; abdominal ultrasonography; routine liver function tests and a battery of neuropsychological tests and EEG. Three venous blood samples were taken at 8 pm, 4 am and 8 am, from all patients and controls, for serum melatonin assay using ELISA kits. It was found that at 8 pm the mean serum melatonin level is significantly lower in patients than in controls, while at 4 am and 8 am the mean levels were significantly higher in patients than in controls; being at the highest level at 4 am. There was a positive significant correlation between the mean serum levels of melatonin at different times and the Child's grading of the patients. On the other hand, the patients with liver cirrhosis showed significantly abnormal results of the psychometric tests than controls. EEG was found to be slower in patients than controls as indicated by significantly slower alpha mean frequency. There was a significant positive correlation between the change in the serum melatonin level at 4 am and 8 am and the result of Bender- Gestalt test [a test of visual motor coordination]; a negative correlation between the performance on digit- symbol test [a test of attention / concentration and executive motor functions] and the serum melatonin level at 4 am. It could be suggested that the change in the serum melatonin level in patients with liver cirrhosis may have a role in the pathogenesis of the changes in the cognitive functions occurring in hepatic encephalopathy. Hypothetically, this might prove later on to have a therapeutic implication in the management of these patients