Reperfusion injury after ischemia primarily results in which type of cellular injury?

Reperfusion injury after ischemia primarily results in which type of cellular injury?

• A. Irreversible cell damage
• B. Reversible cell injury
• C. No injury occurs
• D. Fibrosis and scarring

Answer: (A)

Reperfusion injury after ischemia pushes cells from a reversible state toward irreversible cell damage because of a burst of oxidative stress and calcium overload that damages membranes and mitochondria. During ischemia, the lack of oxygen depletes ATP and disrupts ion pumps, causing cellular swelling and other reversible changes. When blood flow is restored, reactive oxygen species are generated in abundance and inflammatory cells flood in. The ROS, together with Ca2+ influx, promote mitochondrial permeability transition, collapse of the membrane potential, and activation of destructive enzymes. These events lead to loss of membrane integrity and irreversible cellular injury (necrosis). Fibrosis and scarring are longer-term outcomes after tissue necrosis, not the immediate type of injury seen with reperfusion.

Reperfusion injury after ischemia pushes cells from a reversible state toward irreversible cell damage because of a burst of oxidative stress and calcium overload that damages membranes and mitochondria. During ischemia, the lack of oxygen depletes ATP and disrupts ion pumps, causing cellular swelling and other reversible changes. When blood flow is restored, reactive oxygen species are generated in abundance and inflammatory cells flood in. The ROS, together with Ca2+ influx, promote mitochondrial permeability transition, collapse of the membrane potential, and activation of destructive enzymes. These events lead to loss of membrane integrity and irreversible cellular injury (necrosis). Fibrosis and scarring are longer-term outcomes after tissue necrosis, not the immediate type of injury seen with reperfusion.