Platelet number in different anticoagulants as a diagnostic biomarker for increased intestinal permeability

The main pathological process associated to increased intestinal permeability is the translocation of toxic products, predominantly endotoxins/lipopolysaccharide (LPS), from the intestinal tract into the microcirculation. In blood, LPS binds to surface receptors on immune cells initiating an inflammatory response. LPS can also bind to platelets leading to preactivated platelets that have a lower threshold to be aggregated in presence heparin. The aim of this study was to validate a simple, fast and reliable test for screening LPS-loaded platelets. This test named PANDA (acronym for Platelet Number in Different Anticoagulants) consists in the measurement of the mean platelet number in blood samples collected into EDTA and heparin. We analyzed blood samples from 92 patients with gastrointestinal diseases and 23 healthy volunteers and found a markedly low number of platelets in heparinized blood compared to EDTA-anticoagulated blood in patients but not in healthy volunteers. Furthermore, ex vivo addition of endotoxin to blood samples induced a remarkable decrease in platelet count in heparinized blood of the volunteers but not in the patient's group, where platelets could be previously saturated by endotoxin circulating in blood. Platelet should be counted during the first hour after blood collection, in order to avoid false results due to a progressive platelet aggregation in heparinized blood in function of the time. Our results demonstrated that PANDA test can be used for screening LPS-loaded platelets as an indirect diagnostic biomarker for increased intestinal permeability and also for monitoring the gut barrier function during the treatment of gastrointestinal diseases.