June 30, 2001 WASHINGTON (AP) - Researchers have discovered what they believe is the cause of blood pressure problems in patients suffering cirrhosis, potentially a first step in slowing the disease.
In people suffering advanced cirrhosis, blood vessels become dilated, lowering blood pressure and increasing blood flow to the liver and gut. Due to liver scarring, this increased blood flow meets with resistance, resulting in elevated pressure where the vessels meet the liver.
That can cause fluid to accumulate in the abdomen and dilated blood vessels to rupture - both life-threatening complications.
In tests on animals, the research team, led by Dr. George Kunos of the National Institute of Alcoholism and Alcohol Abuse, found that substances normally present in the body, called endocannabinoids, act on the blood vessel walls to cause dilation.
The researchers found elevated levels of the endocannabinoid anandamide associated with low blood pressure in two separate animal studies of cirrhosis. Using a chemical that blocks the action of anandamide, they raised blood pressure and reduced the so-called portal pressure where the blood enters the liver.
In addition to finding higher levels of anandamide in the cirrhosis cases, they also discovered that the blood vessels of the victims had increased receptors to react to that chemical.
The finding may suggest an approach for therapy to assist patients while they await a liver transplant, the researchers suggest in their paper. The findings are reported in the July issue of the journal Nature Medicine.
Kunos was out of the country and could not be reached to discuss the work.
Dr. Bruce Bacon of the St. Louis University School of Medicine, who was not involved in the study, said the finding is ``a significant observation and an important one.''
But he cautioned, ``whether that will lead to therapeutic intervention (in people) is yet to be determined.''
Copyright 2001 The Associated Press. All rights reserved.
