Embargoed news from Annals of Internal Medicine

October 15, 2012

1. Short-term Sleep Deprivation Significantly Decreases Insulin Sensitivity in Fat Cells

Over Time, Regular Sleep Deprivation May Lead to Metabolic Disorders Such as Diabetes and Obesity

(Sound bites and b-roll footage available. See bottom of page for feed dates, times, and coordinates)

Short-term sleep deprivation reduces insulin sensitivity in the body's peripheral tissue, including fat cells. Over time, this can lead to metabolic disorders such as type 2 diabetes and obesity, as insulin helps to regulate appetite and energy metabolism. Results of this first-of-its-kind study are being published in the October 16 issue of Annals of Internal Medicine, the flagship journal of the American College of Physicians (ACP).

Seven healthy, lean men and women aged 18 to 30 were studied in a sleep lab during two study periods, at least four weeks apart. In random order, participants underwent four nights of 8.5 hours of sleep and four nights of 4.5 hours of sleep. Physical activity and caloric intake were strictly controlled regardless of sleep duration. At the end of each study period, researchers gave participants an intravenous glucose-tolerance test to measure total-body insulin sensitivity. The researchers also performed a biopsy of abdominal fat cells to measure how the fat cells responded to insulin. After four nights of restricted sleep, volunteers' total-body insulin response decreased by an average of 16 percent, and insulin sensitivity of fat cells decreased by 30 percent. According to the researchers, this reduction is akin to taking the fat cell functioning of a healthy person down to that of an obese or diabetic patient.

"In our study, seven out of seven subjects had a significant change in insulin sensitivity after a brief period of sleep restriction," said lead study author, Matthew Brady, PhD, Assistant Professor of Medicine and member of the Committee on Molecular Metabolism and Nutrition at the University of Chicago Medicine. "This is significant because sleeping four to five hours a night during the work week is not uncommon. People think they can function cognitively on little sleep, but our study proves they are not tolerating the metabolic consequences."

According to the authors of an accompanying editorial, this is the first clinical study to examine the causal pathways by which reduced sleep duration may directly contribute to diabetes and obesity. They write that the study results point to a much wider influence of sleep on bodily functions, including metabolism, adipose tissue, cardiovascular function, and possibly more.

The editorial authors caution that the study did not specify whether researchers standardized participants' exposure to light, so it is difficult to determine if changes in the functionality of adipocytes were due to sleep deprivation or duration of exposure to light (or darkness).

Note: For an embargoed PDF, please contact Angela Collom. To interview the lead author, please contact John Easton at John.Easton@uchospitals.edu or 773-795-5225.


2. Quick Turnaround Tests Are an Accurate Screening Option for Hepatitis C

An estimated 170 million persons worldwide are infected with the hepatitis C virus (HCV), a leading cause of liver disease, cirrhosis, and death. Screening is important, as many of those infected are undiagnosed. Tests recommended by the United States Centers for Disease Control and Prevention (CDC) are highly accurate, but they are expensive and have long turnaround times for results. Researchers reviewed 19 published studies to determine the diagnostic accuracy point-of-care screening tests (POCTs) and rapid diagnosis tests (RDTs) in screening for HCV. They found that POCTs of blood (serum, plasma, or whole blood) have the highest accuracy, followed by RDTs of serum or plasma and POCTs of oral fluids. According to the study authors, POCTs and RDTs are accurate enough to be suitable for screening initiatives, especially those targeted to marginalized and at-risk populations and in endemic HCV settings.

Note: For an embargoed PDF, please contact Angela Collom. To interview the lead author, please contact Julie Robert at julie.robert@muhc.mcgill.ca 514 934-1934 ext. 71381


3. Explanted ICDs Safe and Effective for Reuse

An implantable cardioverter-defibrillator (ICD) can save patients with threatening arrhythmias from sudden cardiac arrest. But in low- and middle-income countries, rates of ICD implantation are very low due to the cost of the device. Many ICDs have clinically useful battery life remaining when explanted. Researchers sought to determine if these explanted ICDs can be resterilized and reused. The study authors implanted explanted ICDs in 81 consecutive consenting patients. The researchers found that the devices continued to function normally and deliver appropriate, life-saving therapy. There were no instances of infection related to ICD implantation and no evidence of ICD malfunction. The authors conclude that a resterilization and implantation strategy for explanted ICDs could have important humanitarian and economic effects for citizens of low- and middle-income nations.

Note: For an embargoed PDF, please contact Angela Collom. To interview the lead author, please contact Lee-Ann Landis at leeann.landis@jefferson.edu or 215-955-2240.


-end-


American College of Physicians

Related Insulin Articles from Brightsurf:

US Insulin prices 8 times higher than in other nations
Insulin list prices in the United States have increased dramatically over the past decade, with per person insulin spending doubling between 2012 and 2016.

A gatekeeper against insulin resistance in the brain
The brain plays a major role in controlling our blood glucose levels.

Sorting and secreting insulin by expiration date
Visualizing the age of insulin secreting granules in cells allowed researchers to investigate how cells' preference for secreting newer granules is disrupted in diabetes.

Researchers develop a new ultrafast insulin
Stanford researchers tested a new insulin drug in diabetic pigs and found that it was twice as fast-acting as traditional insulin.

Insulin signaling suppressed by decoys
The discovery of an insulin 'decoy' molecule from the lab of Matthew Gill, PhD, in Florida shakes up understanding of insulin signaling, with implications for diabetes, longevity and aging research.

New mechanism for dysfunctional insulin release identified
In a new study, researchers at Uppsala University have identified a previously unknown mechanism that regulates release of insulin, a hormone that lowers blood glucose levels, from the β-cells (beta cells) of the pancreas.

Type 2 diabetes is not just about insulin
Obesity, by promoting the resistance to the action of insulin, is a major risk factor of diabetes.

The insulin under the influence of light
By understanding how the brain links the effects of insulin to light, researchers (UNIGE) are deciphering how insulin sensitivity fluctuates according to circadian cycles.

Does insulin resistance cause fibromyalgia?
Researchers led by a team from The University of Texas Medical Branch at Galveston were able to dramatically reduce the pain of fibromyalgia patients with medication that targeted insulin resistance.

Insulin insights
Insulin triggers genome-wide changes in gene expression via an unexpected mechanism.

Read More: Insulin News and Insulin Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.