P8RI (D-P8RI) is a CD31 biomimetic peptide and agonist targeting the juxtamembrane amino acid sequence of the ectodomain of CD31, restoring the CD31 inhibitory pathway and exhibiting immunosuppressive properties.

P8RI (D-P8RI) was engineered as a retro-inverso peptide composed of all-D-amino acids to preserve bioactivity and provide resistance to plasma proteases[1].

P8RI, administered at a dosage of 2.5 mg/kg through subcutaneous injections daily from days 7 to 28 following acute aortic dissection and intramural hematoma (ADIM) occurrence, significantly mitigates aneurysmal transformation. This effect is achieved by hastening the resolution of intramural hematomas, fostering collagen production in dissected aortas, and enhancing M2 macrophage enrichment at the injury site in vivo. The efficacy of this treatment was evaluated using an Apo E -/- male mouse model, 28-week-old, with implanted Ang II-releasing pumps—a model designed to simulate experimental acute aortic dissection and intramural hematoma (ADIM). This regimen resulted in a marked reduction of aneurysmal transformation.