Roles of hepatic progenitor cells activation, ductular reaction proliferation and Notch signaling in morbid obesity.

BACKGROUND/AIMS: Hepatic progenitor cells (HPCs) activation, proliferative ductular reaction (DR), replicative arrest and Notch signaling have been demonstrated in a variety of human liver diseases. The relationships are poorly understood in morbid obesity. We investigated factors responsible for the HPCs/DR, replicative arrest and Notch signaling in non-NASH and NASH groups.

METHODOLOGY: Cytokeratin 7 (and 19), p21, CD34, Ki67 and different Notch receptors and ligands immunohistochemical stained biopsies from morbid obese patients with non-NASH (n=10) and NASH (n=25) were studied. These results were correlated with clinicopathological variables.

RESULTS: NASH patients presented with abnormal liver function tests and had higher HbA1c percentage. Strong association between HPCs and DR was seen (r=0.785, p<0.000). BMI, interface activity and replicative arrest were associated with HPCs expansion and DR in NASH patients. A strong association between CD34 with HPCs and DR was found in non-NASH patients. In NASH group, Notch 3 was important in bile ductular proliferation; whereas Notch 4 was associated with sinusoidal neovessels proliferation and Kupffer cell activation.

CONCLUSIONS: HPCs and DR played an important role in hepatic regeneration in fatty liver disease of morbid obesity. An altered replication pathway in NASH promotes HPCs activation and DR. Notch-3 and Notch-4 were significantly different between non-NASH and NASH groups.