Urinary Extracellular Vesicle ENaC Marker for Direct MR Activity Assessment
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Solution Overview
Problem
There is no direct indicator for assessing mineralocorticoid receptor (MR) activity, making early detection of excessive MR activation difficult, which is a risk factor for cerebrovascular and cardiovascular diseases.
Innovation Solution
A method for measuring MR activity using the protein quantity of an epithelial sodium channel subunit in urinary extracellular vesicles, with a preferred indicator being the ratio of γENaC to CD9, allowing for early detection and treatment of excessive MR activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If blood aldosterone concentration is used as an indicator, then MR activity can be indirectly assessed, but it cannot directly reflect MR activity and is affected by many other factors
Solution Approach 1:
The patent uses urinary extracellular vesicles as an intermediary carrier to transport ENaC subunit proteins from renal tubular cells to urine. These vesicles protect the proteins from degradation and provide a stable, direct indicator of MR activity in the kidney, resolving the contradiction between indirect assessment and direct reflection of MR activity.
Solution Approach 2:
The patent extracts and measures specific ENaC subunit proteins (particularly γ-subunit) from urinary extracellular vesicles. This extraction approach isolates the direct marker of MR activity from the complex blood environment, providing a reliable and specific measurement that is not confounded by other systemic factors affecting blood aldosterone levels.
2Measurement precision
If blood samples are used for measurement, then MR activity can be assessed, but the method is invasive and complex
Solution Approach 1:
The patent utilizes urine as an intermediary fluid that naturally contains extracellular vesicles carrying ENaC proteins from the kidney. This approach replaces invasive blood sampling with simple urine collection, dramatically improving ease of operation while maintaining measurement precision through direct detection of renal MR activity markers.
Solution Approach 2:
The kidney tubular cells automatically secrete extracellular vesicles containing ENaC proteins into the urine as part of normal physiological function. This self-service mechanism provides a continuous, spontaneous source of MR activity markers in urine, eliminating the need for invasive procedures and enabling routine monitoring.
3Reliability
If MR inhibitors are used for treatment, then MR activity is suppressed, but blood aldosterone concentration does not decrease, preventing assessment of therapeutic effect
Solution Approach 1:
The patent employs urinary ENaC protein levels as an intermediary marker that directly reflects functional MR activity in the kidney. Since MR inhibitors suppress MR-mediated ENaC expression, this intermediary marker provides a reliable and precise measurement of treatment response, overcoming the limitation of blood aldosterone concentration which remains unchanged due to feedback mechanisms.
Data Source
AI summary
[Problem] Various pathological conditions cause a mineralocorticoid receptor (MR) to be activated, and excessive activation of the MR is a risk factor of onset of cerebrovascular and cardiovascular diseases. However, no indicator has provided direct assessment of MR activity, and hence early detection of excessive MR activation has remained difficult. An object of the present invention is to find an indicator that can directly assess MR activity.[Solution] It has been found that MR activity can be directly assessed by using, as an indicator, a protein quantity of an epithelial sodium channel (ENaC) subunit in urinary extracellular vesicles. The indicator is preferably a ratio of a protein quantity of an ENaC subunit to a protein quantity of an internal control protein in the extracellular vesicles. A specific aspect is a ratio of y subunit of ENAC to CD9 (γENaC/CD9). A test is performed for a disease associated with MR activation to allow an early start of treatment. The early start of treatment enables prevention of onset of cerebrovascular and cardiovascular diseases.