Stories about: endocrinology

Adrenal gland offers a new view of tissue regeneration and maintenance

A confocal micrograph of a mouse adrenal gland. The green stripes radiating from the outer region containing the zona glomerulosa (zG) to the inner region containing the zona fasiculata (zF) provide evidence for direct lineage conversion of these two differentiated cell types.
In this mouse adrenal gland, the green stripes radiating from the outer region containing the zona glomerulosa (zG) to the inner region containing the zona fasiculata (zF) provide evidence for direct lineage conversion of these two cell types.

In 2006, Shinya Yamanaka, MD, PhD, discovered a way to reprogram mature skin cells back to a stem cell state so they can be converted into any cell type a scientist is interested in studying. That work earned him last year’s Nobel Prize in Physiology or Medicine.

Yamanaka’s discovery raised the tantalizing question of whether similar reprogramming ever occurs in nature. In fact, it does, discovered David Breault, MD, PhD, an endocrinologist at Boston Children’s Hospital and a member of the Harvard Stem Cell Institute. In the journal Developmental Cell, Breault recently showed that the adrenal gland uses cellular reprogramming (called lineage conversion) for daily maintenance and to repair itself after injury.

“This is going to be important for how we think of tissue maintenance and regeneration,” Breault says.

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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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