Would it be possible to diagnose endometriosis from a vaginal swab?

Promising genomic evidence derived from mast cells for endometriosis diagnosis

Key Points

Highlights:

• Inflammation and new vessel formation in endometriosis may be promoted by "mast cell-derived exosomal tRF-Leu-AAG-001".

Importance:

• Exosomal tRF-Leu-AAG-001 from vaginal leukorrhea could be a potential diagnostic biomarker for endometriosis.

What’s done here:

• Endometrial tissues and vaginal secretion (leucorrhea) were sampled from hospitalized women in a single center.
• Exosomal tRF-Leu-AAG-001 derived from mast cells were isolated from samples by differential centrifugation.
• Samples from patients with (n=26) and without endometriosis (n=25) were compared. 
• From mast cell lines infected with tRF-Leu-AAG-001 siRNA, expression of inflammatory factors and the alteration in vascular capacity were evaluated.

Key results:

• In ectopic tissue exosomes 63 up-regulated and 45 down-regulated tRFs&tiRNAs were identified. 
• When tRF-Leu-AAG-001 was selected as a candidate marker by enrichment and PCR verification, high expression was observed in ectopic foci mast cells.
• siRNA silencing of tRF-Leu-AAG-001 expression showed a significant decrease in IL-6, IL-10, IL-1β, and TNF-α, and angiogenic ability was dramatically reduced.
• The expression of exosomal tRF-Leu-AAG-001 in leucorrhea had high specificity and sensitivity for predicting the occurrence of ectopic disease.

Lay Summary

Ectopic endometrial tissues with new vessel formations in an inflammatory background have a component of mast cell-derived exosomal tRF-Leu-AAG-001 promoting inflammation and angiogenesis.

This information is according to the paper published in a recent issue of the journal “BMC Women’s Health”, by Dr. Li and associates from Ningbo Women and Children’s Hospital, Ningbo, China. 

Currently, laparoscopy with tissue biopsy is the gold standard for the diagnosis of endometriosis in clinical management strategies. 

Eutopic and ectopic endometrial tissues (when present), and leucorrhea were collected in a single medical center for a one-year period. There were 51 patients enrolled in this study, of whom 26 were diagnosed with endometriosis through laparoscopy and histopathological examination, and the remaining 25 patients without endometriosis were evaluated as the control group.

Exosomal tRF-Leu-AAG-001 derived from mast cells were isolated from samples by differential centrifugation, and small RNA sequencing was performed to detect the exosomal tRNA halves (tiRNAs)&tRFs. RNA probe and immunofluorescent antibody were used to localize the origin of tRFs. Exosomes are small extracellular vesicles having a 30-150  nm diameter secreted by living cells. They are present in various body fluids and spaces between cells.

In endometriotic tissues, 63 up-regulated and 45 down-regulated tRFs&tiRNAs were identified. When tRF-Leu-AAG-001 was selected as a candidate marker by enrichment and PCR verification, high expression was found in ectopic foci mast cells. siRNA silencing of its expression showed a significant decrease in IL-6, IL-10, IL-1β, and TNF-α; along with a dramatically reduced angiogenic ability. Also, the expression of exosomal tRF-Leu-AAG-001 in leucorrhea had high specificity and sensitivity for predicting the occurrence of ectopic disease. The authors suggest that leucorrhea exosomal tRF-Leu-AAG-001 could be a potential diagnostic biomarker for endometriosis.

Future studies on more clinical samples may support the reliability of exosomal tRF-Leu-AAG-001 as a non-invasive diagnostic marker of endometriosis.

Research Source: https://pubmed.ncbi.nlm.nih.gov/35752827/