Tissue obtained during heart surgery elucidates autophagy changes during ischemia

Image: PD Apoptosis regulator BAX protein

1. Right atrial tissue showed increased expression of genes promoting autophagy following ischemia-reperfusion injury.

2. Samples were obtained pre and post-cardioplegic arrest from the same patients, comparing each patients’ differential gene expression to themselves as controls.

Evidence Rating Level: 2 (Good)

Study Rundown: Atrial tissue sampled from patients after cardiac arrest showed increased expression of autophagy promoting genes when compared with atrial tissue from the same patients before this ischemic insult. Since autophagy is suggested to reduce apoptosis, these findings provide some mechanistic support for the proposed technique of minimizing infarct size by pharmacologically enhancing autophagy.

Click to read the study in The Journal of Thoracic and Cardiovascular Surgery

In-Depth: Tissue samples of 16 patients were analyzed by polymerase chain reaction and immunohistochemistry. Post-ischemic tissue showed upregulation of 11 autophagy-related genes and downregulation of 3, as well as suppression of mTOR, an inhibitor of autophagy. LC3-II proteins, associated with autophagosome formation, were also elevated following ischemia and reperfusion, consistent with downstream activation of autophagy.

By Gina Siddiqui and Allen Ho

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