Objectives: The aim of the present investigation was to study the endogenous circadian clock phase rhythm in cirrhotic patients.
Methods: The study population comprised 13 patients with cirrhosis (seven in Child-Pugh class A and six in classes B/C) and nine healthy controls. Plasma melatonin, tissue plasminogen activator antigen, and plasminogen activator inhibitor 1 antigen were measured at 4-h intervals over a 24-h period. Multiple-components rhythmometry using population mean cosinor methods were employed to analyze the findings.
Results: All three variables were characterized in both patients and controls by a statistically significant circadian rhythm, with similar profiles. The peak times of tissue plasminogen activator and plasminogen activator inhibitor 1 antigens were practically identical in controls and cirrhotic patients, irrespective of Child-Pugh class (calculated peak at times 6:52, 6:56, and 7:20 for the inhibitor in controls and Child-Pugh class A and classes B/C patients, respectively; p = ns), whereas the peak of melatonin was delayed in classes B/C patients (at times 2:08, 1:56, and 4:00, respectively; p < 0.05).
Conclusion: The similar circadian phases of plasminogen activator inhibitor antigen in controls and cirrhotic patients in the present investigation indicates that the output rhythm of the internal timekeeping system is not shifted in this pathological condition.