Exosomes and exosomal cargo in urinary extracellular vesicles: novel potential biomarkers for mineralocorticoid-receptor-associated hypertension

Comprehensive strategy for identifying extracellular vesicle surface proteins as biomarkers for chronic kidney disease

Chronic kidney disease (CKD) poses a significant health burden worldwide. Especially, obesity-induced chronic kidney disease (OCKD) is associated with a lack of accuracy in disease diagnostic methods. The identification of reliable biomarkers for the early diagnosis and monitoring of CKD and OCKD is crucial for improving patient outcomes. Extracellular vesicles (EVs) have emerged as potential biomarkers in the context of CKD. In this review, we focused on the role of EVs as potential biomarkers in CKD and OCKD and developed a comprehensive list of EV membrane proteins that could aid in the diagnosis and monitoring of the disease. To assemble our list, we employed a multi-step strategy. Initially, we conducted a thorough review of the literature on EV protein biomarkers in kidney diseases. Additionally, we explored papers investigating circulating proteins as biomarkers in kidney diseases. To further refine our list, we utilized the EV database Vesiclepedia.org to evaluate the qualifications of each identified protein. Furthermore, we consulted the Human Protein Atlas to assess the localization of these candidates, with a particular focus on membrane proteins. By integrating the information from the reviewed literature, Vesiclepedia.org, and the Human Protein Atlas, we compiled a comprehensive list of potential EV membrane protein biomarkers for CKD and OCKD. Overall, our review underscores the potential of EVs as biomarkers in the field of CKD research, providing a foundation for future studies aimed at improving CKD and OCKD diagnosis and treatment.

Recent progress in the diagnosis and treatment of primary aldosteronism

Primary aldosteronism (PA) is caused by excessive secretion of aldosterone from the adrenal glands, with subsequent changes in the renin-angiotensin system. In Japan, chemiluminescent enzyme immunoassay is currently performed for aldosterone assay rather than the earlier method of radioimmunoassay. This change in aldosterone measurement methods has resulted in faster and more accurate measurement of blood aldosterone levels. Since 2019, esaxerenone, a mineralocorticoid receptor antagonist (MRA) with a non-steroidal skeleton, has been available in Japan for the treatment of hypertension. Esaxerenone has been reported to have various effects, such as strong antihypertensive and anti-albuminuric/proteinuric effects. Treatment of PA with MRAs has been reported to improve the patient's quality of life and to suppress the onset of cardiovascular events independent of their effects on blood pressure. Measuring renin levels is recommended for monitoring the extent of mineralocorticoid receptor blockade during MRA treatment. Patients receiving MRAs are prone to developing hyperkalemia, and combining MRAs with sodium/glucose cotransporter 2 inhibitors is expected to prevent severe hyperkalemia and provide additional cardiorenal protection. Mineralocorticoid receptor-associated hypertension is a broad concept of hypertension that includes not only PA, but also hypertension caused by borderline aldosteronism, obesity, diabetes, and sleep apnea syndrome. New findings on primary aldosteronism, which is part of MR-associated hypertension. Aldosterone measurements have been changed to the CLEIA method. Treatment of primary aldosteronism with MRAs has a variety of positive effects. CT-guided radiofrequency ablation and transarterial embolization are alternatives to surgery for aldosterone-producing adenomas. BP blood pressure, CLEIA chemiluminescent enzyme immunoassay, CT computed tomography, K serum potassium, MR mineralocorticoid receptor, MRA mineralocorticoid receptor antagonist, QOL quality of life, SGLT2i sodium/glucose cotransporter 2 inhibitor.

Update on Hypertension Research in 2021

In 2021, 217 excellent manuscripts were published in Hypertension Research. Editorial teams greatly appreciate the authors' contribution to hypertension research progress. Here, our editorial members have summarized twelve topics from published work and discussed current topics in depth. We hope you enjoy our special feature, "Update on Hypertension Research in 2021".

Urinary extracellular vesicle as a potential biomarker of exercise-induced fatigue in young adult males

Purpose

Previous studies have suggested that circulating extracellular vesicles (EVs) arise after high intensity exercise and urine could reflect the plasma proteome. Herein, we investigated the characteristic of urinary EVs from healthy young adult males who had completed a maximal effort exercise test.

Methods

Thirteen healthy men completed a 20 m shuttle run test (20 m SRT). Fresh urine samples were collected at first morning, right after, and 1 h rest after 20 m SRT. Also, blood lactate, heart rate, rating of perceived exertion, and blood pressure were measured before, right after, and 1 h rest after 20 m SRT. Urinary EVs were analyzed using Exoview instrument and microRNAs (miRNAs) sequencing on urinary EVs were performed.

Results

Urinary EVs increased significantly after exercise and returned to baseline value after 1 h of rest. miRNA sequencing on urinary EV revealed alterations in four miRNAs (1 up and 3 down) and nine miRNAs (2 up and 7 down) in pre- vs. post- and post- vs. post-1 h samples, respectively. Lastly, bioinformatic analysis of urinary EV miRNA suggests that predicted target genes could affect PI3K-Akt, mitogen-activated protein kinase, and insulin pathways by exercise.

Conclusions

Exercise to voluntary exhaustion increased the number of EVs in urine. Also, miRNAs in urinary EVs were altered after exercise. These findings could indicate the possibility of using the urinary EVs as a novel biomarker of acute exercise-induced fatigue.