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New approach to reducing damage after a heart attack

New approach to reducing damage after a heart attack

During the emergency procedure used to reopen the blocked artery causing a heart attack, smaller “micro” blood vessels can remain constricted causing significant damage. A new study led by Associate Professor Neil Herring and published in the European Heart Journal has established a key cause behind this constriction and identified a potential therapeutic target to block the mechanism behind it.

Cardiovascular disease is the main cause of death in the UK and throughout the Western World. One of the most common ways in which that manifests is through heart attacks, which occurs when one of the heart’s arteries is blocked. During a heart attack part of the heart starts to die, which causes pain in the chest and can be life-threatening.

Large heart attacks are treated with an emergency procedure to reopen the blocked artery using a balloon and metal tube called a stent. Whilst this procedure is often life saving, in around one third of cases smaller “micro” blood vessels beyond the stent remain constricted causing significant damage. The cause of these micro-vessels being very tightly constricted has so far been unclear.

A new study led by Professor Neil Herring has shed light on why this may happen. Innovative new research has uncovered evidence that the issue relates to the amount of stress the patient experiences during the heart attack. As part of the stress response, a neurotransmitter called Neuropeptide-Y (NPY) is released which causes micro-vessels in the heart to constrict. Furthermore, their data has demonstrated that patients with high NPY levels tend to go on to experience more heart damage.

To establish these results, the team studied patients who had experienced large heart attacks. They measured the levels of NPY both within the heart and peripheral blood. Alongside this, they took accurate and sophisticated measures of how constricted the small blood vessels were at the time. Through state of the art scans at 48 hours and 6 months after heart attack, researchers were able to see how much damage had been done to the heart. ‘We were able to correlate quite nicely the levels of NPY in the heart with how constricted the blood vessels were and even how much damage was done to the heart 6 months later,’ said Professor Herring.

The next step was to understand the mechanism behind how NPY causes this constriction. By studying isolated blood vessels in an animal model, researchers identified a key receptor that NPY binds to to cause the construction. They were then able to compare these results with samples of human hearts taken at the time of surgery, which clearly demonstrated that the receptor is also present in the human heart.

The crucial finding at this stage indicated that drugs that block the NPY receptor can reduce the damage of a heart attack in an experimental model. ‘That gives us real impetus to say if we can come up with a drug that we can use in humans that can block that receptor, then this may be a really good new treatment that we may be able to give to heart attack patients,’ said Professor Herring. Further studies are needed to establish whether NPY blocking drugs reduce the damage caused by a heart attack in patients and help improve survival.

The study is in collaboration with the Herring Group, the Oxford Acute Myocardial Infarction (OxAMI) Study led by Professor Keith Channon from the Oxford Heart Centre and the Radcliffe Department of Medicine, and Professor Kim Dora at the Department of Pharmacology. The research was supported by the British Heart Foundation and has been published in the European Heart Journal.

The full publication, ‘Neuropeptide-Y causes coronary microvascular constriction and is associated with reduced ejection fraction following ST-elevation myocardial infarction,’ can be read in the European Heart Journal.

Materials provided by University of Oxford

Situs Inversus Totalis

Bizarre case study reveals man with his body organs on the wrong side

A medical emergency room with the patient turned into a tale of an unexpected tale in the case of a 66-year-old man who turned up at the hospital with coughs and chest pains. Only for the doctors to realize that the internal organs of the patients were on the wrong side of the body like the heart was on the right, liver on the left, etc. The report was published in the New England Journal of Medicine.

This condition is named as Situs inversus totalis and it is not life changing as it sounds. This was discovered due to modern medical scanning tools and many people had lived their lives without any diagnosis. The doctors have said that the patient was migrated to the United States after being in a refugee camp for 20 years. The findings as shown by the chest radiograph were dextrocardia in which the heart is situated on the right rather than on the left and a mirror image transposition for the abdominal organs. The symptoms of the man included chest pain, congestion and coughing and a little pain on the left of the abdomen as seen on the medical reports.

This case is very rare but not unheard. Donny Osmond is a well-known case of Situs Inversus Totalis where all internal organs are flipped like a mirror image and this common type affects close to 1 in 10,000 people. Such people are generally seen wearing a bracelet that declares and signals the doctor of this disorder in case of an emergency surgery where the doctor might mistakenly open the wrong part of the body. The heart is the part where most of the complication occurs in the case of Situs Inversus and dextrocardia in which the key important arteries can end up lying in parallel rather than crisscrossing which makes the heart surgery and transplants very difficult to operate.

The name of this abnormality was coined by Matthew Baillie in 1788 which is “location” and “opposite” in Latin and this terminology is continued by doctors and scientists even today. One recent case was reported of Rose Marie Bentley who lived up to the age of 99 years and no one knew about this abnormal condition until her death report came. Her heart was on the correct side of the body which makes Situs Inversus much more dangerous.

Situs Inversus is often dismissed as an X-ray error after the reports when the baby is born and is the reason why people aren’t diagnosed until many years later.

soft total artifical heart

For the first time scientists successfully create a complete heart by 3D printing

A team of researchers at the Tel Aviv University has managed to successfully 3D print a small heart by using human tissues which includes blood vessels, biological molecules and collagens. This is considered to be a remarkable achievement as the scientists hope that with the help of this, they can make organ donation to be a thing of the past.

This achievement was reported by head researchers from TAU’s Faculty of Life Sciences, Professor Tal Dvir, Dr. Assaf Shapira and his doctoral student Nadav Noor in the Advanced Science journal.

The 3D printed heart is the size of a rabbit’s and it is not fully functional yet. However, the team has pointed out that the technology involved in 3D printing the heart for a human body is essentially the same. There are several steps of improvement left in the heart as the cells need to possess the pumping ability, a crucial working of the heart. Currently, the group of cells can contract but they need to work together. The scientists believe that they can succeed in increasing the efficiency of the method.

So the next step in the line is to make the printed heart grow and mature in the laboratory and make it learn how to function like an actual heart. Only after then can scientists take the decision to use it for transplant in animals for testing their functionality. This is a very time-consuming process and it may take years before this technology can create actual functioning organs that are ready to transplant. Nevertheless, this is a significant progress, as three-dimensional printing has managed to print tissues but not the blood vessels, which is very important for its working.

Dr. Dvir said that this is the first time, a team has successfully managed to engineer and print an entire heart with all the components inside it, the cells, blood vessels, chambers.

Scientists have previously printed cartilage and aortal tissues, but the main challenge was not accomplished, which is to create tissues with complete vascularization, blood vessels, capillaries. In the absence of these, the organs would not survive.

The scientists began the process with fatty tissues extracted from the human body and then they separated the cellular components from the non-cellular components. After that, they programmed these cells to undifferentiated stem cells which can be nudged to form cardiac cells or endothelial cells. The non-cellular materials such as the proteins galore were processed to form a personalized hydrogel which served as printing ink.

Organ printing basically involves three stages. The first stage is called the pre-print stage, which involves scanning the organ. The second stage is printing the organ and the third stage is maturing the organ in a proper environment.