An attempt to predict daily erythrocyte lithium fluctuations

Area of Science:

• Pharmacokinetics
• Biochemistry
• Neuroscience

Background:

• Erythrocyte lithium concentration is a superior predictor of brain lithium levels compared to plasma concentrations.
• Accurate hourly determination of erythrocyte lithium levels post-intake is challenging due to time-dependent variability.
• Understanding lithium transport kinetics is crucial for managing affective disorders.

Purpose of the Study:

• To determine the kinetic rate constants for lithium transport in erythrocytes in vitro.
• To establish a reliable erythrocyte load constant (K0) for lithium.
• To enhance laboratory time management for lithium flux pre-controls.

Main Methods:

• In vitro determination of kinetic rate constants using erythrocytes from healthy volunteers.
• Utilized different high lithium-loaded, plasma-like media.
• Employed an extrapolation procedure to determine constants and the erythrocyte load constant.

Main Results:

• The erythrocyte load constant (K0) was determined to be 0.0161 +/- 0.0005 h-1 at corresponding plasma lithium concentrations.
• Demonstrated that lithium accumulation in RBCs is time-dependent and increases with extracellular lithium concentration.
• Established a method for in vitro determination of lithium transport abnormalities.

Conclusions:

• The determined erythrocyte load constant (K0) facilitates improved laboratory time management for lithium flux pre-controls.
• In vitro determination of lithium transport abnormalities can aid in understanding the etiology of affective illness.
• This research provides a valuable tool for more precise lithium level monitoring and clinical application.