Human heart tissue development slower than other mammals
The walls of the human heart are a disorganised jumble of tissue until relatively late in pregnancy despite having the shape of a fully functioning heart, according to a pioneering study.
A University of Leeds-led team developing the first comprehensive model of human heart development using observations of living foetal hearts found surprising differences from existing animal models.
Although they saw four clearly defined chambers in the foetal heart from the eighth week of pregnancy, they did not find organised muscle tissue until the 20th week, much later than expected.
Developing an accurate, computerised simulation of the foetal heart is critical to understanding normal heart development in the womb and, eventually, to opening new ways of detecting and dealing with some functional abnormalities early in pregnancy.
Studies of early heart development have previously been largely based on other mammals such as mice or pigs, adult hearts and dead human samples. The Leeds-led team is using scans of healthy foetuses in the womb, including one mother who volunteered to have detailed weekly ECG (electrocardiography) scans from 18 weeks until just before delivery.
This functional data is incorporated into a 3D computerised model built up using information about the structure, shape and size of the different components of the heart from two types of MRI (Magnetic Resonance Imaging) scans of dead foetuses' hearts.
Early results from the project, which involves researchers from Leeds, the University of Edinburgh, the University of Nottingham, the University of Manchester and the University of Sheffield, show that the human heart may develop on a different timeline from other mammals.
While the tissue in the walls of a pig heart develops a highly organised structure at a relatively early stage of a foetus's development, a paper from the Leeds-led team published in the Journal of the Royal Society Interface Focus reports that the there is little organisation of the human heart's cells until 20 weeks into pregnancy.
A pig's pregnancy lasts about three months and the organised structure of the walls of the heart emerge in the first month of pregnancy. The new study only detected similar organised structures well into the second trimester of the human pregnancy. Human foetuses have a regular heartbeat from about 22 days.
Dr Eleftheria Pervolaraki, Visiting Research Fellow at the University of Leeds' School of Biomedical Sciences, said: "For a heart to be beating effectively, we thought you needed a smoothly changing orientation of the muscle cells through the walls of the heart chambers. Such an organisation is seen in the hearts of all healthy adult mammals.
"Foetal hearts in other mammals such as pigs, which we have been using as models, show such an organisation even early in gestation, with a smooth change in cell orientation going through the heart wall. But what we actually found is that such organisation was not detectable in the human foetus before 20 weeks," she said.
Professor Arun Holden, also from Leeds' School of Biomedical Sciences, said: "The development of the foetal human heart is on a totally different timeline, a slower timeline, from the model that was being used before. This upsets our assumptions and raises new questions. Since the wall of the heart is structurally disorganised, we might expect to find arrhythmias, which are a bad sign in an adult. It may well be that in the early stages of development of the heart arrhythmias are not necessarily pathological and that there is no need to panic if we find them. Alternatively, we could find that the disorganisation in the tissue does not actually lead to arrhythmia."
A detailed computer model of the activity and architecture of the developing heart will help make sense of the limited information doctors can obtain about the foetus using non-invasive monitoring of a pregnant woman.
Professor Holden said: "It is different from dealing with an adult, where you can look at the geometry of an individual's heart using MRI (Magnetic Resonance Imaging) or CT (Computerised Tomography) scans. You can't squirt x-rays at a foetus and we also currently tend to avoid MRI, so we need a model into which we can put the information we do have access to."
He added: "Effectively, at the moment, foetal ECGs are not really used. The textbooks descriptions of the development of the human heart are still founded on animal models and 19th century collections of abnormalities in museums. If you are trying to detect abnormal activity in foetal hearts, you are only talking about third trimester and postnatal care of premature babies. By looking at how the human heart actually develops in real life and creating a quantitative, descriptive model of its architecture and activity from the start of a pregnancy to birth, you are expanding electrocardiology into the foetus."
More information: The full paper, "Antenatal architecture and activity of the human heart," is published in the Journal of the Royal Society Interface Focus and is posted online. dx.doi.org/10.1098… fs.2012.0065
Provided by University of Leeds
- Researchers find our inner reptile hearts Sep 14, 2012 | not rated yet | 0
- Fruit fly hearts similar to human hearts Feb 27, 2007 | not rated yet | 0
- Researchers examine developing hearts in chickens to find solutions for human heart abnormalities (Video) Jan 21, 2009 | not rated yet | 0
- Stem cells train heart following heart attack Nov 21, 2007 | not rated yet | 0
- Study looks at why heart attacks cause so much more damage in late pregnancy Jul 02, 2012 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Why is zone 1 in liver more prone to ischemic injury?
21 hours ago Hi, Is it because around central vein, there is only deoxygenated blood from the vein where as in the periphery there is hepatic artery. Also why...
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013 As title suggest. Thanks :smile:
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013 Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
- More from Physics Forums - Medical Sciences
More news stories
By discovering the new mechanism by which estrogen suppresses lipid synthesis in the liver, UC Irvine endocrinologists have revealed a potential new approach toward treating certain liver diseases.
Medical research 9 hours ago | not rated yet | 0 |
Aortic arch pulse wave velocity, a measure of arterial stiffness, is a strong independent predictor of disease of the vessels that supply blood to the brain, according to a new study published in the June issue the journal ...
Medical research 9 hours ago | not rated yet | 0
Since the discovery of Prontosil in 1932, sulfonamide antibiotics have been used to combat a wide spectrum of bacterial infections, from acne to chlamydia and pneumonia. However, their side effects can include serious neurological ...
Medical research 11 hours ago | not rated yet | 0 |
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as ...
Medical research 11 hours ago | 5 / 5 (2) | 0 |
Spanish researchers have discovered that the daily clearance of neutrophils from the body stimulates the release of hematopoietic stem cells from the bone marrow into the bloodstream, according to a report published today ...
Medical research 13 hours ago | 5 / 5 (2) | 0
(Medical Xpress)—Regulating the distribution of power in neurons is done by a system that makes the national electric grid look simple by comparison. Each neuron has several thousand mitochondria confined ...
8 hours ago | 4.8 / 5 (5) | 0 |
A brief visual task can predict IQ, according to a new study. This surprisingly simple exercise measures the brain's unconscious ability to filter out visual movement. The study shows that individuals whose ...
13 hours ago | 4.4 / 5 (9) | 0 |
Teams of highly respected Alzheimer's researchers failed to replicate what appeared to be breakthrough results for the treatment of this brain disease when they were published last year in the journal Science.
11 hours ago | 5 / 5 (1) | 2 |
High blood glucose is associated with poor outcomes in hospitalized patients, and use of intensive insulin therapy (IIT) to control hyperglycemia is a common practice in hospitals. But the recent evidence does not show a ...
1 hour ago | not rated yet | 0
Little is known about why asthma develops, how it constricts the airway or why response to treatments varies between patients. Now, a team of researchers at Weill Cornell Medical College, Columbia University Medical Center ...
12 hours ago | not rated yet | 0 |
Ethnic background plays a surprisingly large role in how diabetes develops on a cellular level, according to two new studies led by researchers at the Stanford University School of Medicine.
9 hours ago | not rated yet | 0 |