All members of the NPY family are abnormal in both patients with IBD and animal models of human IBD.
The abnormality in NPY appears to be a primary factor contributing to IBD, and is caused by interaction between immune cells and NPY neurons in the enteric nervous system during inflammation.
Abnormalities in PYY and PP seem to be secondary to the changes caused by abnormalities in other gut neurohormonal peptides/amines during inflammation.