Day: 12/28/2015

Interrupted sleep impacts mood more than lack of sleep, study finds.

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After a bad night’s sleep, you are unlikely to be in the best of moods. But according to a new study, your bad mood may be down to lack of quality sleep, rather than lack of quantity.
[A man woken by his alarm]
Researchers say interrupted sleep is more likely to lead to poor mood than lack of sleep.

Published in the journal Sleep, the study found that people whose sleep was frequently interrupted for 3 consecutive nights reported significantly worse mood than those who had less sleep due to later bedtimes.

Lead study author Patrick Finan, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine in Baltimore, MD, and colleagues say their findings indicate sleep interruption is more detrimental to mood than lack of sleep, which may shed light on the association between depression andinsomnia.

According to the National Sleep Foundation, adults aged 18-64 should aim to get around 7-9 hours of sleep each night, while those aged 65 and older should get around 7-8 hours of sleep nightly. The Foundation say getting enough sleep can help boost the immune system, productivity and mood.

But increasingly, studies are showing that the quality of sleep is just as important as duration of sleep. “When your sleep is disrupted throughout the night, you don’t have the opportunity to progress through the sleep stages to get the amount of slow-wave sleep that is key to the feeling of restoration,” notes Finan.

Interrupted sleep led to 31% reduction in positive mood

Finan and colleagues demonstrated the effect of disrupted sleep on mood in their study of 62 healthy men and women who, over 3 consecutive nights in a clinical research suite, were randomized to one of three sleep conditions.

One group had uninterrupted sleep each night, one group had delayed bedtimes, while the remaining group was deliberately awakened eight times during sleep each night.

The sleep stages of each subject were monitored using polysomnography, which records brain waves, blood oxygen levels, breathing, heart rate and eye and leg movements during sleep.

At the end of each night, participants were asked to report how strongly they felt positive or negative emotions, such as anger or cheerfulness, which the researchers assessed to determine their mood.

While there were no differences in mood between groups after the first night, participants in the interrupted sleep group experienced a 31% reduction in positive mood after the second night, while those in the delayed sleep group experienced a 12% reduction in positive mood. These reductions persisted after the third night.

The team says there were no significant differences in negative mood between the delayed sleep group and interrupted sleep group on any of the 3 days, indicating that interrupted sleep has a more adverse impact on positive mood.

Poor slow-wave sleep may explain link between insomnia, depression

On assessing the polysomnography results over the 3 nights, the researchers found that the interrupted sleep group experienced shorter periods of slow-wave sleep, or deep sleep – the sleep stage that is deemed important for body repair and maintenance – than the delayed sleep group.

Fast facts about insomnia

  • Insomnia is when a person has trouble falling asleep, maintaining sleep or frequently awakens during sleep
  • Insomnia is only deemed a disorder when it causes significant distress or anxiety, or when it results in daytime impairment
  • It is estimated that around 1% of children and 7% of adolescents in the US have insomnia.

What is more, the team found that this lack of slow-wave sleep among the interrupted sleep group was significantly associated with the reduction in positive mood, and that disturbed sleep impacted certain aspects of positive mood, including friendliness and feelings of sympathy.

The team believes their findings help explain why many people with chronic insomnia – a sleep disorder that affects around 10% of the US population – experience depression; it may be down to insufficient amounts of slow-wave sleep.

“Many individuals with insomnia achieve sleep in fits and starts throughout the night, and they don’t have the experience of restorative sleep,” explains Finan. “You can imagine the hard time people with chronic sleep disorders have after repeatedly not reaching deep sleep.”

He notes, however, that further studies are warranted to gain a better understanding of the sleep stages experienced by people with insomnia.

Last month, Medical News Today reported on a study suggesting that adultsmay only need 6.5 hours sleep each night.

ARB Therapy May Slow Emphysema Progression

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A subset of patients with chronic obstructive pulmonary disease (COPD) with emphysema appeared to benefit from treatment with an angiotensin receptor blocker, supporting preclinical evidence of efficacy, a randomized clinical study suggested.
Overall, patients with COPD treated with losartan (Cozaar) had no improvement compared with placebo-treated patients. However, the subset of patients with emphysema at baseline had stabilization of emphysema at 6 months, whereas patients in the placebo group exhibited a 3% rate of progression (P=0.042). Anatomic analysis also showed a significant difference for the left upper lobe in favor of losartan (P=0.049).

At 12 months, the overall trend toward stability persisted in the patients who had emphysema at baseline but was no longer significant. The anatomical analysis showed a consistent pattern of stability with losartan versus progression with placebo, achieving statistical significance in the right middle lobe, Allison Lambert, MD, of Johns Hopkins, reported here at CHEST 2015.
“From these data, we conclude that, among patients with COPD who have CT-defined emphysema, losartan has the potential to prevent emphysema progression,” said Lambert. “Our secondary outcomes were unchanged.
“The next step in our line of clinical investigation will be to conduct a phase III clinical trial, supported by the NIH Pulmonary Trials Consortium. We anticipate recruiting 220 patients with emphysema, which will afford 90% power to detect differences as identified in our phase II trial.”
The emergence of differences between the groups after a relatively brief treatment period was impressive, but the timing of medication administration and CT scans could influenced findings, suggested Jay Peters, MD, of the University of Texas Health Science Center in San Antonio.
“One of my concerns is that [the improvement] was in the left upper lobe early on and then the right middle lobe at 12 months,” said Peters. “How did you control the time of day that the CT was done and how did that correlate with the medications? It would seem that somebody who had just taken medication with air trapping could look quite different.”

Alluding to data showing that the right middle lobe is the most common site of progression with CT-defined emphysema, Lambert responded, “I do think that this finding within the right middle lobe at 12-month follow-up is true and perhaps compelling. What was striking to me at the 12-month follow-up was the trend across all lobes; all the lobes had stopped progressing.”
The rationale for using ARBs in emphysema dates back to preclinical studies of Marfan syndrome. Animals with emphysema-like changes in alveoli were treated with losartan, which partly reversed the changes. Subsequent studies in mice showed that losartan attenuated adverse lung effects of cigarette smoke and restored lung architecture.
Relevant clinical studies include a trial of the ARB irbesartan (Avapro) in patients with COPD, leading to some changes associated with improved lung function and architecture. A retrospective case-control study showed a reduction in COPD hospitalization and mortality among patients treated with statins and ARBs.
In her presentation here, Lambert reported findings from a randomized, proof-of-concept study to determine whether losartan would prove or slow the progression of emphysema in patients with COPD. Patients with mild to moderate COPD were randomized to losartan or placebo and followed for 12 months. Outcomes of interest included CT-assessed percent emphysema and airway wall thickness; spirometry, lung volumes, and diffusing capacity of the lung for carbon monoxide; and quality of life/health status.
The final analysis included 106 patients, for whom Lambert reported anatomic and functional outcomes. In the overall population, patients assigned to losartan did no better than those in the placebo group with respect to any of the outcomes at 6 or 12 months. However, a prespecified analysis of patients with CT-confirmed emphysema at baseline (n=46) showed anatomical changes favoring the losartan group.

At 6 months, total-lung emphysema had decreased by 0.78% in the losartan group and increased by 3.03% in the placebo group (P=0.042). The lobe-specific anatomic analysis showed a 0.86% decrease in emphysema in the left upper lobe among patients treated with losartan versus an increase of 2.97% in the placebo group (P=0.049). Other lobe-specific values did not differ significantly between the groups, nor did any of the functional outcomes assessed.
At 12 months, patients in the losartan group still had an overall decrease in emphysema (-0.32%) compared with an increase of 2.18% in the placebo group, but the difference was no longer significant (P=0.064). Emphysema in the right middle lobe had decreased by 0.72% in the losartan group but increased by 3.34% in the placebo group (P=0.019).
All of the other lobe-specific assessments showed stable disease in the losartan arm versus 2% to 3% emphysema progression with placebo, although the differences did not achieve statistical significance. None of the functional outcomes differed significantly between treatment groups.

Curbing Premature Birth May Hinge on a Single Molecule

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Blocking a molecule in the uterus could delay or even halt premature birth, the leading cause of death and disability of newborns worldwide, according to a new study in rodents.

Normal pregnancies last between 38 and 42 weeks. However, more than 10 percent of all infants are born prematurely, after less than 37 weeks of pregnancy. As many as 3 percent are born quite prematurely, after less than 31 weeks of pregnancy, said study co-senior author Dr. David Cornfield, a pediatric pulmonary medicine physician and scientist at Stanford University in California.

Premature birth can lead to major problems because many organs, including the brain, lungs, and liver, need the final weeks of pregnancy to fully develop.

“There is a huge burden — financial, emotional, psychological, developmental — that premature infants and families must bear,” Cornfield said. “The societal costs are similarly huge.”

During pregnancy, the womb shelters a growing fetus. When a woman goes into labor, the uterus experiences powerful contractions to push out the baby. It remains poorly understood as to what makes the womb begin the labor process. As such, there is currently no effective treatment for premature labor.

Previous research suggested that calcium levels of muscle cells within the walls of the uterus help control womb contractions. As a result, Cornfield and his colleagues focused on a molecule found in the mouse uterus known as TRPV4, which helps control the flow of calcium into cells.

The scientists found that uterine tissue from pregnant women possessed higher levels of TRPV4 than non-pregnant women. Similarly, as pregnancy advanced in mice and rats, TRPV4 became increasingly abundant in the uterine wall muscle cells of these rodents.

Previous research discovered molecules that could activate TRPV4 so that it would permit calcium to flow into cells. In experiments, these compounds increased uterine contractions in mice, the researchers found.

Prior studies also identified molecules that could block TRPV4, preventing it from allowing calcium to enter cells. In experiments where mice were given drugs known to set off premature labor, these inhibitor compounds significantly prolonged pregnancy and prevented premature labor.

“This advance can to be used to develop treatments to stop preterm labor, and perhaps to increase the efficacy of uterine contractions so as to decrease the need for cesarean sections,” Cornfield told Live Science.

Future research will need to investigate if this approach can safely work on humans, Cornfield said.