Navigation Links
A potential biological cause for sudden infant death syndrome

New autopsy data provide the strongest evidence yet that sudden infant death syndrome (SIDS) is not a "mystery" disease but has a concrete biological basis. In the November 1 issue of JAMA, researchers at Children's Hospital Boston document abnormalities in the brainstem ?a part of the brain that regulates breathing, blood pressure, body heat, and arousal ?in babies who died from SIDS.

SIDS is the leading cause of death in American infants after the newborn period, affecting 0.67 in 1,000 live-born babies. Although epidemiologic studies have identified risk factors for SIDS, such as putting babies to sleep on their stomachs, and protective factors like pacifier use, there has been little understanding of SIDS's biologic basis.

"Researchers led by neuropathologist Hannah Kinney, MD, and neuroscientist David Paterson, PhD, at Children's Hospital Boston and Harvard Medical School examined brain autopsy specimens from 31 infants who had died from SIDS and 10 who had died acutely from other causes, provided by the San Diego Chief Medical Examiner's office. Examining the lowest part of the brainstem, known as the medulla oblongata, they found abnormalities in nerve cells that make and use serotonin, one of over 100 chemicals in the brain that transmit messages from one nerve cell to another.

Based on their findings, Kinney, Paterson and colleagues hope to develop a diagnostic test to identify infants at risk for SIDS. They also envision a drug or other type of treatment to protect infants who have abnormalities in their brainstem serotonin system.

The brainstem serotonin system is thought to help coordinate breathing, blood pressure, sensitivity to carbon dioxide, and temperature during waking and sleep. When babies sleep face-down or have their faces covered by bedding, they are thought to re-breathe exhaled carbon dioxide, therefore breathing in less oxygen. Normally, the rise in carbon dioxide activates nerve cells in the brain stem, which in turn stimulate respiratory and arousal centers in the brain so that the baby doesn't asphyxiate.

"A normal baby will wake up, turn its head, and start breathing faster when carbon dioxide levels rise," explains Kinney.

But in babies who die from SIDS, defects in the serotonin system may impair these reflexes, the researchers believe.

Kinney previously documented serotonin receptor abnormalities in two other populations of SIDS infants, including American Indian infants in the Northern Plains, whose SIDS rate is among the highest in the world. The current study confirms those findings in a third population and, for the first time, pinpoints multiple defects in the serotonin system other than those in serotonin receptors: deficiencies in a particular type of serotonin receptor (called 5HT1A), an abnormally high number of serotonergic neurons (neurons that make and release serotonin), a preponderance of immature serotonergic neurons, and evidence for insufficient amounts of the serotonin transporter protein, which "recycles" serotonin so that nerve cells can reuse it.

"We provide strong evidence that SIDS is a biological problem, and that the brainstem serotonin system is a good place to focus continued research efforts," says Paterson.

He and Kinney believe that the abnormalities they observed begin during early fetal development, and that prenatal insults like maternal smoking and alcohol use may adversely affect development of the brainstem serotonin system during this time. More research is needed to explain what causes the abnormalities and how they can be prevented.

The findings also provide a biological explanation for why SIDS occurs twice as often in males than females ?male SIDS infants had significantly fewer 5-HT1A receptors than female SIDS infants.

In addition, serotonin abnormalities help explain why infants under 6 months are most vulnerable to SIDS. At birth, babies must adjust from being totally dependent on their mother to breathing on their own and maintaining their own blood pressure. If the brainstem serotonin system is defective or still immature, this transition to total independence in the control of vital functions may be impaired during the crucial first six months of life.

"We think that the control systems for vital or homeostatic functions reach full maturity only towards the end of the first year of life," Kinney says.

The researchers note that despite the national Back to Sleep campaign, which urges caregivers to put babies to bed on their backs, 65 percent of the SIDS infants in this study were found sleeping on their stomach or side.

Source:Children's Hospital Boston

Related biology news :

1. MetaChip provides quick, efficient toxicity screening of potential drugs
2. Simple drug has the potential to save many lives threatened by malaria
3. Scripps scientists find potential for catastrophic shifts in Pacific ecosystems
4. Engineers improve plastics potential for use in implants by linking it to biological material
5. Human embryonic stem cells have the potential to develop into eggs and sperm in the laboratory
6. Improving the potential of cancer vaccines
7. Snapin: A protein with therapy potential for autism
8. Slipping past the blood brain barrier: Research shows potential treatment for brain cancer
9. LIAI scientists make major finding on potential smallpox treatment
10. Neurotransmitters signal aggressive cancer, offer potential for early diagnosis
11. Researchers develop new testing methods for potential monkeypox or smallpox outbreak

Post Your Comments:

(Date:11/19/2015)... , Nov. 19, 2015  Based on its ... & Sullivan recognizes BIO-key with the 2015 Global Frost ... year, Frost & Sullivan presents this award to the ... catering to the needs of the market it serves. ... line meets and expands on customer base demands, the ...
(Date:11/17/2015)... , November 17, 2015 Paris ...   --> Paris from 17 th ... DERMALOG, the biometrics innovation leader, has invented the first combined ... on the same scanning surface. Until now two different scanners ... one scanner can capture both on the same surface. ...
(Date:11/16/2015)... 16, 2015  Synaptics Inc. (NASDAQ: SYNA ... today announced expansion of its TDDI product portfolio ... controller and display driver integration (TDDI) solutions designed ... new TDDI products add to the previously-announced ... (WQHD resolution), and TD4322 (FHD resolution) solutions. All ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... -- Tikcro Technologies Ltd. (OTCQB: TIKRF) today announced that its Annual General Meeting ... Israel time, at the law offices of ... th Floor, Tel Aviv, Israel . ... Izhak Tamir to the Board of Directors; , election of ... approval of an amendment to certain terms of options granted to our ...
(Date:11/24/2015)... , ... November 24, 2015 , ... ... the environment are paramount. Insertion points for in-line sensors can represent a weak ... the InTrac 781/784 series of retractable sensor housings , which are designed ...
(Date:11/24/2015)... , Nov. 24, 2015 /CNW Telbec/ - ProMetic Life Sciences ... today that Mr. Pierre Laurin , President and Chief ... at the upcoming Piper Jaffray 27 th Annual Healthcare ... on December 1-2, 2015. st , at ... one-on-one meetings throughout the day. The presentation will be available ...
(Date:11/24/2015)... , Nov. 24, 2015  PDL BioPharma, Inc. (PDL) (NASDAQ: ... , the company,s president and chief executive officer, will present ... next week in New York City . ... Tuesday, December 1, 2015 at 9:30 a.m. EST. ... to the website at least 15 minutes prior to the ...
Breaking Biology Technology: