University Park, Pa. --- A Penn State bioengineer says his experiments with young and old rats show that the response of their blood vessels to compromised circulation is so different as to suggest that young and old human patients may need different treatment based on age
Dr. Norman R. Harris, assistant professor of bioengineering, says "Most researchers currently use young, healthy rats for blood vessel research because they are more readily available, cost less and have fewer health problems. However, our experiments indicate a fundamental difference between the two age groups."
Harris studies the response of small blood vessels to the reduction or cessation in blood flow, which can occur during heart attack, stroke, surgery or other circulatory problems. When circulation slows or ceases and then is restored, a condition known as ischemia-reperfusion or I/R, inflammation and swelling can occur. Harris notes that when I/R-induced inflammation and swelling occur in the brain or lungs, death can result.
Recent research has suggested that I/R-induced inflammation and swelling often occur as the result of an accumulation of neutrophils, the most abundant white blood cells, on the walls of the blood vessel.
The Penn State bioengineer has shown that in 2-month-old rats, neutrophils do, in fact, accumulate and trigger the vessel leakage that leads to inflammation and swelling, but in 2-year-old rats, no such accumulation occurs.
In his most recent experiments, Harris induced I/R in both young and old rats and also administered a serum that prevented the accumulation of neutrophils. In the young rats, the prevention of the accumulation also resulted in the prevention of the leakage that leads to inflammation and swelling.
However, in the old rats, leakage still occurred after I/R, indicating that some other cause, other than neutrophil accumulation, was responsible.