Exploring Cellular Water Dynamics Associated With Potassium Ion Changes Using Magnetic Resonance Imaging.

Area of Science:

• Cellular physiology
• Biophysics
• Medical imaging

Background:

• Potassium ions are vital for cellular functions.
• The impact of potassium on cellular water dynamics is not well understood.
• Investigating water dynamics in relation to potassium concentration is crucial.

Purpose of the Study:

• To investigate in vitro water dynamics using MRI.
• To determine the effects of increasing potassium concentration ([K+]) on cellular water.
• To analyze changes in intracellular and extracellular water compartments during cell swelling.

Main Methods:

• Jurkat cells were subjected to elevated extracellular [K+] and hypoosmotic stress.
• Multi-echo spin-echo and selective inversion-recovery fast spin-echo MRI sequences were employed.
• T2 and magnetization transfer (MT) parameters were estimated to evaluate water dynamics.

Main Results:

• Both elevated [K+] and hypoosmotic stress increased T2, indicating more free water.
• Hypoosmotic stress led to a greater increase in the free water pool compared to [K+] elevation at similar cell swelling.
• The bound water pool per cell increased linearly with cell volume in both conditions, but less so with [K+] elevation.

Conclusions:

• Cell swelling induced by elevated [K+] and hypoosmotic stress alters water dynamics.
• MRI-based T2 and MT parameters reveal distinct patterns of water pool changes.
• Potassium-induced cell swelling involves mechanisms beyond simple osmotic effects.