Chemotactic
peptides bind specifically to receptors on leukocyte membranes. This property makes them prospective vehicles to evaluate
inflammation and
infection. We used two well-established models of
acute pancreatitis to quantitate the binding of the chemotactic
peptide N-formyl-methionyl-leucyl-phenylalanine-
lysine (
fMLFK) to leukocytes and its correlation to degree of organ
inflammation. Uptake of the (99m)Tc-labeled nicotinyl
hydrazine-derivatized chemotactic
peptide analog
fMLFK-HYNIC was measured in blood, pancreas, lung, and muscle specimens in rats with edematous or necrotizing
pancreatitis and was compared with neutrophil sequestration assessed by
myeloperoxidase activity and histology. Chemotactic
peptide uptake in the pancreas was increased in mild and severe
pancreatitis compared with controls, with higher levels in severe than in mild disease, and correlated with tissue
myeloperoxidase activity (r = 0.7395, P < 0.001). Increased pulmonary uptake only in severe
pancreatitis reflected
pancreatitis-induced neutrophil sequestration in the lungs. Muscle uptake was unchanged compared with controls.
Edema formation did not affect chemotactic
peptide uptake. The data suggest that uptake of chemotactic
peptides can contribute to quantitative assessment of neutrophils in localized inflammatory processes and is independent of associated
edema formation or microcirculatory compromise.