Abnormal Signatures of Extracellular Vesicles in Polycythemia Vera

By Patrick Daly - Last Updated: December 20, 2021

Polycythemia vera (PV) is subject to the chronic inflammation commonly observed in other myeloproliferative neoplasms. Recent data point to circulating microbes and microbial components as possible factors in hemopoiesis regulation, such as the extracellular vesicles (EVs) of the inflammatory network. As such, Monica Barone, from the Department of Medical and Surgical Sciences at the University of Bologna in Bologna, Italy, and colleagues examined phenotype and microbial DNA cargo of circulating EVs. They found that EVs holding abnormal phenotype and dysbiosis signatures were associated with PV.

Further, their report, published in Frontiers in Oncology, theorized that these EVs could play a potential role in the inflammatory pathogenesis of the disease. 

The researchers collected peripheral blood and feces samples from 38 patients with PV and 30 healthy donors. EVs derived from circulating megakaryocytes (MK) and platelets (PLT) were measured by flow cytometry. The 16S rDNA V3-V4 region was sequenced from EVs isolated from microbial DNA extracted from fecal samples.

The investigators reported that the proportion of circulating MK–derived EVs in patients with PV was decreased significantly, while the proportion of PLT–derived EVs was increased, when compared to healthy controls. Surprisingly, PV was also associated with a higher diversity and distinct microbial composition in the microbial DNA signature of isolated EVs, relative to healthy counterparts. Notably, EVs with isolated lipopolysaccharide were observed in increased proportions in patients with PV, whereas gut microbiome profiles were not distinct between patients with PV and healthy donors.

The authors surmised that there was indeed an association between PV and circulating EVs harboring abnormal phenotype and dysbiosis signature, though they acknowledged future, larger trials are needed to confirm their findings. They also suggested that their “data might be also of interest in the development of novel personalized therapeutic approaches targeting the microenvironment of PV.

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