Microbiome critical for bone hormone action

PTH (parathyroid hormone) increases calcium levels in the blood and can either drive bone loss or bone formation, depending on how it is produced or Read more

More NMDA but less excitotoxicity? Now possible

Many researchers have wanted to enhance NMDA receptor signals to treat disorders such as schizophrenia. But at the same time, they need to avoid killing neurons with “excitotoxicity”, which comes from excess calcium entering the Read more

Update on pancreatic cancer: images and clinical trial

In 2018, Winship magazine had a feature story on pancreatic cancer. Our team developed an illustration that we hoped could convey the tumors’ complex structure, which contributes to making them difficult to treat. Oncologist Bassel El-Rayes described how the tumors recruit other cells to form a protective shell. "If you look at a tumor from the pancreas, you will see small nests of cells embedded in scar tissue," he says. "The cancer uses this scar Read more

glutathione

Oxidative stress ain’t about free radicals, it’s about sulfur

This recent paper in Circulation, from Arshed Quyyumi and colleagues at the Emory Clinical Cardiovascular Research Institute, can be seen as a culmination of, even vindication for,  Dean Jones’ ideas about redox biology.

Let’s back up a bit. Fruit juices, herbal teas, yogurts, even cookies are advertised as containing antioxidants, which could potentially fight aging. This goes back to Denham Harman and the free radical theory of aging. [I attempted to explain this several years ago in Emory Medicine.]

We now know that free radicals, in the form of reactive oxygen species, can sometimes be good, even essential for life. So antioxidants that soak up free radicals to relieve you of oxidative stress: that doesn’t seem to work.

Dean Jones, who is director of Emory’s Clinical Biomarkers laboratory, has been an advocate for a different way of looking at oxidative stress. That is, instead of seeing cells as big bags of redox-sensitive chemicals, look at cellular compartments. Look at particular antioxidant proteins and sulfur-containing antioxidant molecules such as glutathione and cysteine.

That’s what the Circulation paper does. Mining the Emory Cardiovascular Biobank, Quyyumi’s team shows that patients with coronary artery disease have a risk of mortality that is connected to the ratio of glutathione to cystine (the oxidized form of the amino acid cysteine).

How this ratio might fit in with other biomarkers of cardiovascular risk (such as CRP, suPAR, PCSK9, more complicated combinations and gene expression profiles, even more links here) and be implemented clinically are still unfolding.

Posted on by Quinn Eastman in Heart Leave a comment