Stories about: Division of Endocrinology

Could Burmese pythons shed light on diabetes?

Burmese pythons diabetes

Originally from Southeast Asia, Burmese pythons are perhaps best known in the U.S. for the havoc they’ve been creating in the Everglades. Kept as pets and released into the wild, they can grow to nearly 20 feet long, and are hunting animals like marsh rabbits toward extinction (a problem Florida is trying to address with an annual Python Removal Competition).

But in the lab, at a diminutive 3 feet in length, Burmese pythons may hold valuable lessons about diabetes.

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Can we bypass the bypass to treat diabetes?

Diagram of Roux-en-Y gastric bypass
Gastric bypass surgery creates a small pouch in the stomach and connects it directly to the small intestine. Why does it help type 2 diabetes? (Wikimedia Commons)

Research shows that gastric bypass surgery, aside from inducing weight loss, resolves type 2 diabetes. Though weight loss and improved diabetes often go hand-in-hand, patients who undergo gastric bypass usually end up seeing an improvement in their type 2 diabetes even before they lose weight.

But why? To investigate, a research team led by Nicholas Stylopoulos, MD, of Boston Children’s Hospital’s Division of Endocrinology, spent a year studying rats and observed that after gastric bypass surgery, the way in which the small intestine processes glucose changes. They saw the intestine using and disposing of glucose, and showed that it thereby regulates blood glucose levels in the rest of the body, helping to resolve type 2 diabetes.

Basically, as the team reported recently in Science, the small intestine—widely believed to be a passive organ—is actually a major contributor to the body’s metabolism.

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A mutation and a mystery: Weight gain without a change in energy use

Why did the mouse at left gain so much weight?

Two mice scurry around in an enclosure crossed through with light beams. The beams track their movement to measure their energy expenditure, along with the amount of oxygen they breathe in and carbon dioxide they exhale. The mice, who are siblings, are equally active and are held to the same diet, but there’s one critical difference: One mouse is noticeably heavier than the other.

“These [heavier] mice aren’t burning the fat,” says Joseph Majzoub, MD, chief of endocrinology at Boston Children’s Hospital. “They’re somehow holding onto it.”

In fact, the mice have to be underfed by 10 to 15 percent just to stay as slim as their siblings. Their experiences seem to parallel those of people who complain of gaining weight even when they don’t eat more than others. When allowed to eat as much as they want, the mice quickly begin to eat three to four times as much as the others and balloon to more than twice their size.

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Dads to blame? Genetic research reveals cause for precocious puberty

Whole-exome sequencing reveals a gene mutation that comes into play only if inherited from the father.
Whole-exome sequencing reveals a gene mutation that comes into play only if inherited from the father.

For a small subset of boys and girls who undergo early puberty, there’s now a specific explanation. New genetic research, involving whole-exome sequencing, has identified four novel heterozygous mutations in a gene known as MKRN3. Interestingly, while precocious puberty is more common in girls, all 15 affected children in the study inherited the mutations from their fathers.

Precocious puberty—the development of secondary sexual characteristics before 8 years in girls and 9 years in boys—has been associated with short stature, long-term health risks and an increase in conduct and behavioral disorders during adolescence. Physiologically, there are two types: central and peripheral. Central, the more common form, occurs when the pituitary gland, which controls puberty development, is activated too early.

“While a great deal of genetic studies have focused on the overall genetic contribution to pubertal timing, far less research has been conducted to find specific genetic causes of central precocious puberty,” says Andrew Dauber, MD, MMSc, of the Division of Endocrinology at Boston Children’s Hospital, who co-authored the study, published online this week by The New England Journal of Medicine.

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Genome-wide sleuthing reveals the cause of a baby’s failure to thrive

(Jeremy Burgin/Flickr)

It started with a 10-month-old boy, who I’ll call Jake, who was feeding poorly. Between 6 and 10 months, a time when infants should be growing rapidly, he hadn’t gained a pound. His diapers were constantly wet – he was urinating at a high rate. He was irritable and fussy.

When a lab test found an extremely elevated blood calcium level, Jake was sent to the emergency room. Such an extreme elevation posed a risk of compromising his heart and kidney function. His blood pressure was sky-high. “He needed immediate IV fluid to bring his calcium down, and an immediate workup,” says Andrew Dauber, then a first-year fellow in endocrinology.

Jake was admitted to Children’s and Dauber took part in the consult with his mentor Joel Hirschhorn, a pediatric endocrinologist trained in genetics. “His kidneys were so calcified they were turning into stones,” Dauber recalls. The senior nephrologist on the team said Jake had the most severe case of nephrocalcinosis he’d seen.

The team put Jake on low-calcium formula and his calcium level slowly came down. His diagnosis was idiopathic infantile hypercalcemia — meaning they had no idea what was causing Jake’s calcium levels to be so high.

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In diabetes, inflammation may be part of the solution, not the problem

Boosting proteins normally triggered by inflammation may be a new treatment approach for Type 2 diabetes.

Low-grade inflammation caused by obesity is widely believed to contribute to insulin resistance and type 2 diabetes. But, as it turns out, inflammation activates two proteins that appear critical for maintaining good blood sugar levels. Reporting in Nature Medicine, endocrinology researcher Umut Ozcan demonstrates that activating either of these proteins artificially can normalize blood sugar in severely obese and diabetic mice.

That’s a completely new way of looking at diabetes, and suggests a very different way of treating it.

“This finding is completely contrary to the general dogma in the diabetes field,” says Ozcan. “For 20 years, inflammation has been seen as detrimental, whereas it is actually beneficial.”

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