# A Possible Link between Cell Plasticity and Renin Expression in the Collecting Duct: A Narrative Review

## TL;DR

This review explores the connection between cell plasticity and renin production in the kidney's collecting duct, suggesting a new research direction.

## Contribution

The paper highlights the under-researched link between cell plasticity and renin expression in the collecting duct.

## Key findings

- Renin is produced at low levels in the collecting duct, beyond its traditional site in juxtaglomerular cells.
- Collecting duct cells show plasticity, with the ability to change their type under certain conditions.
- The interplay between cell plasticity and renin expression may offer new insights into kidney function and regulation.

## Abstract

The hormone renin is produced in the kidney by the juxtaglomerular cells. It is the rate-limiting factor in the circulating renin–angiotensin–aldosterone system (RAAS), which contributes to electrolyte, water, and blood pressure homeostasis. In the kidneys, the distal tubule and the collecting duct are the key target segments for RAAS. The collecting duct is important for urine production and also for salt, water, and acid–base homeostasis. The critical functional role of the collecting duct is mediated by the principal and the intercalated cells and is regulated by different hormones like aldosterone and vasopressin. The collecting duct is not only a target for hormones but also a place of hormone production. It is accepted that renin is produced in the collecting duct at a low level. Several studies have described that the cells in the collecting duct exhibit plasticity properties because the ratio of principal to intercalated cells can change under specific circumstances. This narrative review focuses on two aspects of the collecting duct that remain somehow aside from mainstream research, namely the cell plasticity and the renin expression. We discuss the link between these collecting duct features, which we see as a promising area for future research given recent findings.