# The Endothelial‐Independent Effect of Desmopressin, In Vitro, on Platelet Function

## TL;DR

This study shows that desmopressin can affect platelet function and microclot formation in the lab, without needing the endothelium.

## Contribution

The study is the first to demonstrate an in vitro endothelial-independent effect of desmopressin on platelet function.

## Key findings

- Desmopressin increased TEG MA and decreased K-time in experimental samples.
- Fluorescence microscopy showed increased platelet activation and microclot formation in test samples.
- The findings contradict previous literature suggesting no endothelium-independent effect of desmopressin on platelets.

## Abstract

Platelets form the nidus around which the primary hemostatic cascade is amplified and propagated. Desmopressin (DDAVP) has been shown to enhance platelet function through interaction with the endothelium. Evidence suggests that an alternative mechanism of action may exist. We aimed to determine the effect of DDAVP on platelet function and microclotting of plasma proteins in samples from healthy volunteers. We analyzed blood samples in 20 healthy volunteers with no coagulation abnormalities. Control and test samples were drawn from each participant. DDAVP was added in vitro to test samples. All samples were subjected to PFA‐200, viscoelastic (VET) and fluorescence microscopy testing. DDAVP increased TEG MA and decreased K‐time in experimental samples. There was no difference between the means in the clotting times in either of the PFA‐200 groups. Fluorescence microscopy examining platelet activation and microclot formation showed significant increases in both parameters in the test samples. The results contrast current literature, which suggests that DDAVP has no effect on platelet function independent of the endothelium. This is the first study demonstrating an in vitro effect of DDAVP on platelets examined by VET and microscopy. We conclude that a relationship exists between DDAVP exposure, in vitro, platelet activation and microclot formation.