Experimental extrahepatic obstruction of portal vein: documentation of histopathological alterations in liver and extrahepatic tissues

The significance of nonobstructive sinusoidal dilatation of the liver: Impaired portal perfusion or inflammatory reaction syndrome

Sinusoidal dilatation found in the absence of an impaired sinusoidal blood outflow has been so far of unclear significance. Sinusoidal dilatation may actually be a nonspecific feature of impaired portal venous blood inflow, whatever the cause, or a feature of severe systemic inflammatory reaction syndrome, whatever the cause. Sinusoidal dilatation is mainly located in the centrilobular area even in the absence of an outflow block. A predominantly periportal location is specifically found in oral contraceptive users, associated with an inflammatory condition. There is strong evidence for the association of sinusoidal dilatation and oxaliplatin-based chemotherapy but not for estroprogestative steroids or thiopurine derivatives. Exposure to anabolic androgen steroids appears to cause sinusoidal changes different from a mere sinusoidal dilatation.

CONCLUSION

There is evidence of activation of the interleukin-6 and vascular endothelial growth factor pathways in sinusoidal dilatation, but the mechanisms linking the activation of these pathways with the microvascular changes must be identified.

Adverse effects of liver dysfunction and portal hypertension on intestinal adaptation in short bowel syndrome in children

BACKGROUND

The effects of liver dysfunction and portal hypertension on intestinal adaptation in short bowel syndrome are generally unknown. The presence of these disorders may adversely affect the ability to wean these patients from parenteral nutrition.

METHODS

Forty-two infants with short bowel syndrome were placed in one of three Child's classifications, depending on serum bilirubin, prothrombin time, ascites, albumin, and liver biopsy, and compared for time to diet tolerance, time required for parenteral nutrition, and survival. A subgroup of these patients also underwent portal pressure measurement, which was combined with liver biopsy results to compare three groups for the same parameters.

RESULTS

Survival was Child's class A 100%, B 84%, C 61%, while time to feeding tolerance was A 16.3 days, B 20.0 days, C 28 days, and total parenteral nutrition time was A 80.0 days, B 98.0 days, C 100.0 days. In the groups that underwent portal pressure measurement, the survival was group I (normal biopsy and pressure) 100%, group II (abnormal biopsy and normal pressure) 90%, group III (abnormal biopsy and pressure) 66%, while time to feeding tolerance was I 15.0 days, II 18.0 days, III 24.0 days, and total parenteral nutrition time was I 72.0 days, II 94.0 days, III 184.0 days.

CONCLUSIONS

Cholestatic liver disease, especially associated with portal hypertension adversely affects bowel adaptation in short bowel syndrome.

Modulation of acid secretion in common bile duct ligation-related gastropathy in Wistar rats

BACKGROUND

Portal hypertensive gastropathy is associated with fundic gland atrophy, resulting in a decrease in chief and parietal cells, and diminished acid secretion.

METHODS

Acid secretion by isolated parietal cells was measured (acridine orange retention), along with the levels of various second messengers (intracellular Ca(2+), cyclic adenosine monophosphate and protein kinase C) in the common bile duct, ligated portal hypertensive rats and compared with sham-operated controls.

RESULTS

There was a significant decrease in the response of isolated parietal cells to the secretagogues histamine and carbachol. This resulted in the blunted acid secretion in the common bile duct ligated group. In addition, all the second messengers studied were significantly decreased as compared with the sham-operated controls.

CONCLUSION

These results suggest that the blunted acid secretory response in the portal hypertensive rat is caused by an alteration in the intracellular signal transduction mechanism.

Gastropathy and defense mechanisms in common bile duct ligated portal hypertensive rats

Portal hypertensive gastropathy is associated with a broad spectrum of gastric mucosal damage inspite of decreased gastric acid secretion, suggestive of compromised endogenous protective mechanisms. To determine the mechanisms of damage in portal hypertensive gastropathy we measured lipid peroxidation, glutathione, antioxidant and lysosomal enzymes in gastric mucosal homogenates from male Wistar rats with elevated intrasplenic pulp pressure, eighteen days after common bile duct ligation. Thiobarbituric acid-reactive substances and lysosomal enzymes (beta-glucuronidase and acid phosphatase) were increased in the common bile duct ligated group as compared to the sham-operated group. The levels of antioxidant defense enzymes, superoxide dismutase, glutathione peroxidase, catalase and glutathione were decreased as compared to the sham-operated controls. Pre-operative vitamin E administration decreased mucosal lipid peroxidation increased the levels of antioxidant defense enzymes and lowered the lysosomal enzymes. The plasma vitamin E levels in this group were lower when compared to animals receiving it post-operatively. In conclusion, free radical and lysosomal enzyme mediated damage may play a role in portal hypertensive gastropathy.