The Auto-Digestion Hypothesis: Digestive Enzymes on the Prowl

Friday, September 27, 2013 - 2:00pm
Fung Auditorium | Powell-Focht Bioengineering Hall
Geert Schmid-Schönbein

Distinguished Professor of Bioengineering
University of California, San Diego

The Auto-Digestion Hypothesis: Digestive Enzymes on the Prowl


Did you ever wonder why you can digest an intestine that you eat, but hopefully not your own intestine? Man, like many other animals living today and in the past, require a mechanism to degrade biomolecules as food source, a process that involves the powerful digestive enzymes synthesized in the pancreas. These enzymes degrade food in the lumen of the intestine and are retained inside the intestinal lumen by the mucosal barrier. This important barrier - made up of epithelial cells and a mucin protein layer - becomes permeable in shock and allows the digestive enzymes to escape from the lumen into the wall of the intestine. As the digestive enzymes enter into the tissue they digest the intestine itself, generate lipid and protein fragments that are cytotoxic, and escape into the systemic circulation. Once in the circulation, the combination of digestive enzymes and fragments they generate causes cell dysfunctions, such as acute insulin resistance, peripheral organ failure and death. This mechanism establishes auto-digestion and death as a price for a life-long benefit to extract biomolecules and metabolic energy from the environment. I will discuss current approaches to interfere with autodigestion and the potential to reduce multi-organ failure in shock patients.


Geert W. Schmid-Schönbein is Distinguished Professor, Director of the Microcirculation Laboratory and Chairman of the Department of Bioengineering at UCSD. He received his Ph.D. degree in Bioengineering at UCSD. After a Post-doctoral Fellowship in the Department of Physiology of Columbia University, New York, he joined the faculty of the Department of Bioengineering at UCSD in 1979 where he has served ever since. He teaches bioengineering of living tissues, cell and molecular biomechanics and has been nominated repeatedly as Teacher of the Year in Bioengineering at UCSD. He is member of many Learned Societies in Engineering and in Medicine. He is Chair of the United States National Committee on Biomechanics and Chair of the World Council for Biomechanics. His research interest is in Microcirculation, Cell and Molecular Mechanics applied to inflammation and pathophysiology of human diseases, including Shock and Multi-Organ Failure, the Metabolic Disease, and Autism.