CURBING HUNGER PANGS
I enjoyed “Turning Down the Food Noise” [The New Science of Diet, Health and Appetite], Lauren J. Young’s article on the influence of satiety pathways on food intake and how glucagonlike peptide 1 (GLP-1) receptor agonists such as Wegovy can intervene successfully. In 2002 I took part in a phase 3 trial of Axokine, a drug candidate from Regeneron that also acted to suppress the desire to overeat. Axokine was never approved by the U.S. Food and Drug Administration because it failed to meet the trial’s endpoint for weight loss across all the participants.
It had a dramatic effect on me when I was in the active arm of the trial, however: I lost about 90 pounds within around nine months. For whatever reason, I was a superresponder. Hence, I have followed the development of other appetite blockers with great interest, although I have not found it necessary to use them. Satiety drugs truly can be life changers.
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JOHN P. MOORE WEILL CORNELL MEDICINE AND SCIENTIFIC AMERICAN’S BOARD OF ADVISERS
I recognized the sensations people reported in Young’s article—not from GLP-1 drugs but from my gastric bypass surgery 19 years ago. I was first aware of a change at Thanksgiving. I had a small portion, then noticed everyone at the table was going for seconds and thirds. I was surprised that I had no desire to do that. I went on to lose almost 200 pounds, and I’ve kept it off without feeling I needed to use my willpower. Have the researchers in the article investigated possible GLP-1 changes in my cohort?
ALAIN MORIN VIA E-MAIL
“Thank you for writing about ticker-tape synesthesia and giving me a name for my mental closed-captioning!” —Schuyler V., Kentucky
In discussing the search for longer-lasting structures of GLP-1, Young says that success was found in the saliva of the Gila monster. I am certain that saliva was not tested because someone said, “Well, let’s test the Gila monster; we’ve tested everything else.” Could you kindly explain how in heaven or through what scientific method this finding was made?
STEPHEN M. ZELMAN NEW YORK CITY
YOUNG REPLIES: Morin’s observation came up during my interview with Giles Yeo of the University of Cambridge. Yeo explained that gastric bypass makes the stomach smaller and the gut shorter in length to reduce food absorption, which leads to weight loss. But the rearrangement of sections of the small intestine, a primary source of GLP-1, also changes gut hormone production. “Suddenly food is delivered further down the gut in a less [digested] form than it would normally be,” Yeo said. “As a result, different hormones are released, including GLP-1.” Several studies show that GLP-1 levels increase almost immediately after gastric bypass surgery—sometimes nearly 10 times higher—before the recipient has lost any weight. These findings suggest that GLP-1’s influence on satiety may play an important role in the surgery’s weight-loss effects.
In response to Zelman: Scientists have long investigated ways to develop drugs from potent chemicals of various venomous creatures, such as snakes, cone snails and lizards like the Gila monster. Research in the 1980s suggested that Gila monster venom stimulated the pancreas, later inspiring endocrinologist John Eng to break down the molecular recipe of the saliva. That’s how he discovered exendin-4, a peptide that was similar in structure and function to GLP-1 but much more durable and longer-lasting. Exendin-4 served as the template for the new class of GLP-1 drugs, first as diabetes drug exenatide and more recently semaglutide.
SEEING SPOKEN WORDS
I was thrilled to read “Speech Transforms into Text I ‘See’ ” [Mind Matters], Emily Makowski’s article on ticker-tape synesthesia. Since childhood, I have seen the words I and others speak appear and scroll before my eyes, much like a ticker tape. I remember being surprised that not everyone experienced this. My parents were always amused by my ability to recite the spellings of words backward.
As mentioned in the article, I find it difficult to concentrate on reading if there are conversations, TV or music with lyrics in the background. Like Makowski, I won spelling bees in primary school—so often that my third grade teacher revised the rules to allow for multiple winners. To my knowledge, I have never met anyone else with ticker-tape synesthesia.
ANNE PRUCHA WINTER SPRINGS, FLA.
I’ve experienced this same speech-to-text conversion for as long as I can remember. I thought everyone experienced this until a conversation with friends in college let me know that, nope, I was fairly unique. This was the first time I’d ever stumbled across something written about the phenomenon. Thank you for writing about ticker-tape synesthesia and giving me a name for my mental closed-captioning!
SCHUYLER V. KENTUCKY
ASTEROID BENNU
“An Asteroid’s Secrets,” by Robin George Andrews, describes the material sampled from the near-Earth asteroid Bennu as having much in common with the geology of our own planet. That makes me wonder whether the asteroid could actually be from Earth, a relic of the huge collision that created our moon. The article says that “some of the sample’s microscopic grains reveal” that Bennu is older than the sun, which is of course older than the moon. But how do those ancient grains confirm Bennu’s age? Couldn’t they be material accreted over the billions of years the asteroid has spent roaming our solar system?
STEVE WISE CHARLOTTE, N.C.
ANDREWS REPLIES: For Bennu to have come from Earth, scientists would expect the sample to have chemical signatures that are a very, very close match to those of Earth or even the moon—and that’s not what they’re seeing. Water-rich objects are actually very common in the solar system, so Bennu being hydrated isn’t that strange. But getting pristine asteroid material from an ancient water world is very exciting.
The sample of Bennu was taken from below its surface. And these grains have clear chemical traces that show they weren’t forged by our sun.
ROUND AND ROUND WE GO
“There Is Too Much Trash in Space,” by the Editors [Science Agenda], discusses the problem of orbital debris. Half a century ago my colleagues and I had a small NASA contract to look at ways to get rid of such debris. We took the unusual step of not asking for follow-on funding because we could not think of anything that would work. Shortly after that I also managed a contract called Space Industrialization, in which we wrestled with that same problem and devised only a partial solution. In our plan, an entrepreneur could lease a “pad” and pay for provided utilities at a space-based facility. If they went broke, management would safely deorbit their hardware.
CHARLES GOULD LAS VEGAS, NEV.
ERRATA
“March of the Mangroves,” by Michael Adno, should have described William “Ches” Vervaeke and Scott F. Jones as using a GPS device, not a GPS transmitter.
In the November issue, the credit for the cover image should have read, “John Gurche/Created for the Institute of Human Origins/Arizona State University.”
