# The KCa3.1 K+ Channel and Cardiovascular Disease: An Upstream Target Linking Inflammation, Fibrosis and Electrical Instability

## TL;DR

The KCa3.1 potassium channel plays a key role in linking inflammation, fibrosis, and electrical instability in various cardiovascular diseases, making it a promising therapeutic target.

## Contribution

This paper identifies KCa3.1 as a central upstream target connecting multiple pathological processes in cardiovascular disease.

## Key findings

- KCa3.1 inhibition reduces atherosclerosis and restenosis in animal models.
- KCa3.1 contributes to atrial fibrillation by promoting electrical and structural remodelling.
- KCa3.1 is implicated in fibrocalcific valve degeneration through inflammatory and osteogenic pathways.

## Abstract

KCa3.1 encodes the intermediate-conductance calcium-activated potassium channel KCa3.1, a regulator of membrane potential and calcium-dependent signalling in cardiovascular and immune cells. Increasing evidence indicates that KCa3.1 is a shared driver of vascular remodelling, inflammation, fibrosis, and electrical instability across multiple cardiovascular diseases. In ischaemic heart disease (IHD), KCa3.1 is upregulated in endothelial cells, vascular smooth muscle cells, macrophages, and T lymphocytes, where it promotes smooth muscle proliferation, neointimal formation, and chronic vascular inflammation. Genetic deletion or pharmacological blockade of KCa3.1 reduces atherosclerotic plaque burden and restenosis in animal models. In atrial fibrillation (AF), KCa3.1 contributes to electrical remodelling by shortening atrial action potential duration and to structural remodelling by driving fibroblast activation and collagen deposition. KCa3.1 also regulates macrophage polarisation and pro-inflammatory cytokine release in atrial tissue, linking immune activation to arrhythmogenic substrate formation. Inhibition of KCa3.1 prolongs atrial refractoriness, attenuates atrial fibrosis, and reduces AF inducibility in multiple preclinical models. Emerging data in valvular heart disease suggest that KCa3.1 is upregulated in valvular interstitial cells and regions of active calcification, where it supports myofibroblast differentiation, osteogenic signalling, and inflammatory crosstalk, implicating the channel in fibrocalcific valve degeneration. Collectively, these findings position KCa3.1 as a central molecular integrator of electrical, fibrotic, and inflammatory pathways in cardiovascular disease. The availability of selective KCa3.1 inhibitors with established human safety profiles supports the feasibility of therapeutic translation. Targeting KCa3.1 may enable disease-modifying strategies that extend beyond symptom control to suppress maladaptive cardiovascular remodelling.