Extracellular vesicles from Wistar Kyoto and spontaneously hypertensive rats have differential vasodilatory responses in resistance arteries

Extracellular vesicles (EVs) have been described as novel bio‐markers and bio‐activators in vascular dysfunction in hypertension (HTN). However, the mechanism by which EVs affect vascular function is unknown. To examine the effects of EVs on acetylcholine (ACh)‐mediated vasodilation, we isolated 3 rd order mesenteric arteries and EVs from 12‐wk old normotensive Wistar‐Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Arteries were cannulated on a pressure myograph and EVs (~6×10 7 EV/mL) were added to the vessel lumen and circulating bath. No significant difference in ACh vasodilation was observed in control WKY and SHR arteries (no EVs). Interestingly, WKY arteries treated with WKY EVs reduced vasodilation compared to control arteries, an effect lost when treated with SHR EVs. ACh‐mediated vasodilation was not altered in SHR arteries when treated with either WKY or SHR EVs. WKY arteries treated with EVs isolated from 6‐wk old WKY and SHR, an age where SHR rats have not yet developed HTN, or with delipidated EVs from 12‐wk old WKY and SHR rats resulted in reduced vasodilation. Together, these data suggest that normotensive EVs reduce ACh‐mediated vasodilation and upon development of hypertension fail to reduced vasodilation. However, reduced vasodilation can be restored by delipidation of the SHR EVs or SHR EVs obtained prior to development of hypertension. Analysis of isolated EVs showed a larger number of CD45‐positive EVs in 12 week‐old SHR rats, indicating an increase in EVs from inflammatory cells following the development of hypertension. Using EVs isolated from human blood samples, a similar reduction in vasodilation was observed in arteries exposed to EVs isolated from normotensive humans. This effect was lost when arteries were treated with EVs isolated from hypertensive patients. This data supports the functional role of EVs in vascular regulation that is altered in HTN. Support or Funding Information K99HL143165, K23HL12610, HL088554 This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .