Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sheep stress programs lamb

23.04.2002


Early life of fetus affects organs’ future health.

Sheep stressed in early pregnancy bear lambs with stunted kidneys that predispose them to high blood pressure Australian researchers have shown. The finding adds to growing evidence that early fetal life influences adult health.

Marelyn Wintour of the University of Melbourne subjected 4-week-pregnant ewes to two stressful days by infusing them with the hormone cortisol. Their lambs developed high blood pressure at 5 months of age, she told the Experimental Biology 2002 meeting in New Orleans on Sunday.



Just before birth, genes that regulate kidney development and blood pressure are more active than normal, she and her colleagues went on to find. As adults, the animals had only two-thirds of the normal number of fluid-filtering units in their kidneys.

Stress forces the cells destined to form the kidney to mature too fast, Wintour believes. This would give the organ less time to grow. "We accelerated maturation by overexpression of these genes," says Wintour. Over time, the inability of the kidney to expel water and salts efficiently may cause blood pressure to rise.

Wintour and others have explored the effects of maternal stress on the fetus before, but this is the first test of the effect of a natural hormone in a large animal. A 4-kilogram lamb weighs roughly the same as a human baby.

Premature physique

Fetal programming is the idea that early events in fetal growth affect an adult’s susceptibility to disease. It was discussed at two sessions of the New Orleans meeting.

Many large epidemiology studies have shown that poor nutrition, which limits fetal growth and reduces birth weight, is associated with increased risk of heart disease, hypertension and adult-onset diabetes.

"It takes it away from the idea that [these diseases] are retribution for adults," says epidemiologist David Barker of the University of Southampton, UK, who originally proposed the fetal-programming hypothesis.

Barker suggests that when conditions are tough - when food is scarce or levels of stress hormones are high, say - the fetus adapts to ensure its survival, perhaps by diverting blood or nutrients to the brain at the expense of other organs. These shifts cause permanent changes in the adult organs. "Everyone has been changed by their experience in fetal life," maintains Barker.

How fetal tissues are permanently altered remains largely unknown. Cells that give rise to an organ may be susceptible to external signals, suggests paediatric researcher Rebecca Simmons of the University of Pennsylvannia in Philadelphia. Anything that interrupts these signals could alter the cell types that survive to contribute to the organ.

This is consistent with Wintour’s finding that kidney development can be altered by stress that occurs even before it has formed. "It was surprising to me that the early time is the critical one," she says.

At the equivalent point in human pregnancy - at around 5-7 weeks - many women are unaware of their condition. Pregnant women who know they are stressed should try and take a little time out to relax or sleep, Wintour suggests.

HELEN PEARSON | © Nature News Service

More articles from Life Sciences:

nachricht Show me your leaves - Health check for urban trees
12.12.2017 | Gesellschaft für Ökologie e.V.

nachricht Liver Cancer: Lipid Synthesis Promotes Tumor Formation
12.12.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Long-lived storage of a photonic qubit for worldwide teleportation

12.12.2017 | Physics and Astronomy

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>