Cell calcium, cell injury and cell death

Area of Science:

• Cell Biology
• Pathology
• Biochemistry

Background:

• Calcium's role in cell injury is under extensive investigation.
• Intracellular calcium shifts are hypothesized to be critical in cellular response to injury.

Purpose of the Study:

• To investigate the effects of calcium regulation on acute lethal anoxic injury.
• To examine the impact of respiration inhibition (cyanide) on calcium dynamics and cell death.
• To correlate calcium shifts with morphological, biochemical, and cytoskeletal changes during cell injury.

Main Methods:

• Utilized three experimental systems: Ehrlich ascites tumor cells, isolated rabbit proximal tubule segments, and cultured rat proximal tubule cells.
• Analyzed calcium movements between extracellular and intracellular compartments, as well as within intracellular compartments.
• Correlated calcium data with morphological, biochemical, and cytoskeletal studies.

Main Results:

• No consistent correlation found between total cell calcium and cell death across all systems, except in specific cases.
• Massive increases in total cell calcium, like mitochondrial Ca3(PO4)2 precipitation, appear secondary to initial injury.
• Intracellular calcium redistribution emerged as a potentially more significant factor in cell death than extracellular calcium in some cell types.

Conclusions:

• Calcium acts as a critical control variable in cell injury, particularly through its intracellular redistribution.
• Mitochondrial calcification is a secondary event in cell injury, analogous to classical dystrophic calcification.
• Intracellular calcium shifts play a more crucial role in cell death than extracellular calcium levels in certain cell types.