Lymphocyte β2-adrenoceptors and plasma catecholamines in patients with cirrhosis

Abstract

The hemodynamic response to propranolol in patients with cirrhosis is heterogeneous. In some patients, there is an expected decrease in portal pressure, whereas in others, portal pressure fails to decrease despite adequate β-blockade. It has been suggested that this lack of response could be related to down-regulation of β2-adrenoceptors, promoted by the increased adrenergic activity frequently found in decompensated cirrhosis. The present study investigated this hypothesis by measuring the density and affinity of lymphocyte β2-adrenoceptors (L-β2-AR), an established index of β2-adrenoceptors in target organs, and the plasma levels of norepinephrine and epinephrine in a group of 32 patients with cirrhosis and portal hypertension. The portal pressure response to propranolol administration (0.1 mg/kg + 2 mg/h) was also investigated (n = 27). Patients with cirrhosis had increased norepinephrine levels (605 ± 360 vs. 224 ± 110 pg/ mL in controls; P < 0.001), but plasma epinephrine level was not increased (136 ± 72 vs. 111 ± 22 pg/mL in controls; NS). There were no differences between cirrhotic patients and controls in the density of L-β2-AR (1398 ± 489 vs. 1278 ± 356 receptors/cell; NS). Portal pressure decreased >10% in 12 patients (responders) and <10% in the remaining 15 (nonresponders). Contrary to previous suggestions, there were no significant differences between responders and nonresponders in relation to the density of L-β2-AR (1362 ± 527 vs. 1487 ± 419 receptors/cell; NS), to the affinity of these receptors (0.15 ± 0.27 vs. 0.13 ± 0.12 nmol/L; NS), to the plasma levels of norepinephrine (661 ± 508 vs. 621 ± 256 pg/mL; NS), and to plasma epinephrine concentration (141 ± 90 vs. 140 ± 75 pg/mL; NS). These results show that the response of portal pressure to propranolol administration is neither related to the density and affinity of L-β2-AR nor to the plasma levels of norepinephrine and epinephrine. Thus, the determination of these parameters cannot substitute measurements of portal pressure to identify those patients with an adequate portal pressure response to propranolol treatment.