New tool predicts deadly form of rare cancer

Two patients with mycosis fungoides (MF) can appear to have identical diseases upon first diagnosis but can have radically different outcomes. MF in an unusual cancer of the T lymphocyte that begins in the skin rather than in the lymph nodes, with the first sign often being a rash. Most patients with MF, the most common type of cutaneous T cell lymphoma (CTCL), have a very slow-growing disease and often have normal life expectancies. But a subset of patients will develop an aggressive, deadly form of the disease that can spread throughout the skin and beyond, becoming untreatable. If identified early, patients with this aggressive form of MF may be eligible for a stem cell transplant to cure the disease, but once MF progresses and becomes treatment resistant, it is nearly impossible to achieve the complete remission required for a successful stem cell transplant.
A tool to accurately determine which early-stage patients are at risk of dying from MF and which patients are likely to only require conventional therapy is desperately needed. Investigators from Brigham and Women’s Hospital have found that next-generation, high-throughput sequencing of a specific gene (T-cell receptor beta or TCRB) is a stronger predictor of which early-stage patients will develop aggressive, progressive MF than any other established factor.
“We are excited to bring precision medicine to the management of MF patients,” said senior author Thomas Kupper, MD, chair of the BWH Department of Dermatology. “While more work needs to be done, we think this approach has the potential to prospectively identify a subgroup of patients who are destined to develop aggressive, life-threatening disease, and treat them in a more aggressive fashion with the intent to better manage, and ideally cure, their cancer.”

Brigham and Women’s Hospitalwww.brighamandwomens.org/about-bwh/newsroom/press-releases-detail?id=3009

Scientists find possible autism biomarker in cerebrospinal fluid

Autism diagnosis is slow and cumbersome, but new findings linking a hormone called vasopressin to social behaviour in monkeys and autism in people may change that. Low vasopressin in cerebrospinal fluid was related to less sociability in both species, indicating the hormone may be a biomarker for autism.
A paper describing the research, which was led by scientists at the Stanford University School of Medicine and the University of California-Davis, was recently published.
“Since autism affects the brain, it’s really hard to access the biology of the condition to know what might be altered,” said Karen Parker, PhD, associate professor of psychiatry and behavioural sciences at Stanford and the lead author of the new study. “Right now, the diagnosis is based on parents’ reports of their children’s symptoms, and on clinicians observing children in the clinic.”
The study’s senior author is John Capitanio, PhD, professor of psychology at UC-Davis.
Autism, a developmental disorder characterized by impaired social abilities, affects 1 in 68 U.S. children. Research has shown that early, intensive behavioural treatment is beneficial. Yet many children don’t receive a timely diagnosis. A biological test, with a specific lab measurement indicating autism, could make diagnosis faster.
Not only is the biology of autism difficult to study in people, but many research animals are unsuited to autism research, Parker said. For instance, mice often fail to show behavioural changes in response to gene mutations that cause autism in people.
So the researchers looked for autism biomarkers in rhesus monkeys, a species whose social capabilities are closer to those of humans. The monkeys had been raised by their mothers in social groups in a primate research colony at UC-Davis. From 222 male animals, the scientists selected 15 with naturally low sociability and compared them with 15 monkeys with naturally high sociability on several biological parameters.
The scientists measured levels of two hormones, oxytocin and vasopressin, in the monkeys’ blood and in their cerebrospinal fluid, which bathes the brain. Both hormones are peptides implicated in a variety of social roles, including parental care and bonds between mates. Some prior studies have hinted that these hormones may also be involved in autism.
Monkeys in the less social group had significantly less vasopressin in their cerebrospinal fluid than monkeys in the more social group. These vasopressin levels accurately predicted the frequency with which individual monkeys participated in social grooming, an important social activity for rhesus monkeys. Vasopressin levels in blood were not different between the two groups. In a second group of 10 monkeys, whose cerebrospinal fluid was sampled four times over four months, the scientists showed that vasopressin levels in the fluid were stable over time.
The researchers also compared vasopressin levels in 14 boys with autism and seven age-matched children without autism. (Vasopressin levels were tested in the children’s cerebrospinal fluid, which was collected via lumbar puncture for medical reasons; their families agreed to allow some fluid to be used for research.) Children with autism had lower vasopressin levels than children without autism, the study found.
“What we consider this to be at this point is a biomarker for low sociability,” Capitanio said.
The researchers now want to test a larger group of monkeys for vasopressin levels to determine whether the hormone levels can distinguish monkeys with low social abilities from others with a wide range of social ability. And they want to explore whether low vasopressin could be detected before symptoms of impaired social ability emerge.
“We don’t know if we see really low cerebrospinal fluid vasopressin before you see behavioral symptoms of autism,” Parker said. “Ideally, it would be a risk marker, but we haven’t studied that yet.”

Stanford School of Medicinemed.stanford.edu/news/all-news/2018/05/scientists-find-possible-autism-biomarker-in-cerebrospinal-fluid.html

Gene disruption signals cerebral palsy and autism link

University of Adelaide researchers have uncovered a genetic signal common to both cerebral palsy and autism.
The finding comes from the first large-scale study of gene expression in children with cerebral palsy.
The researchers, from the University’s Australian Collaborative Cerebral Palsy Research Group in the Robinson Research Institute, also showed common underlying molecular pathways in clinically diverse cerebral palsy. They say both findings add significantly to the weight of evidence for underlying genetic causes of cerebral palsy.
“Cerebral palsy is the most common motor disability of childhood with a frequency of around two in every 1000 live births,” says lead researcher Dr Clare van Eyk, Postdoctoral Research Fellow, Adelaide Medical School, University of Adelaide. “We know that, like autism, it’s a disorder of brain development primarily during pregnancy. But the underlying causes of cerebral palsy are still poorly understood.”
In this study, the researchers use new RNA sequencing technology to measure the gene messengers (RNA) in cells from children with cerebral palsy.
Cell lines from 182 individuals with cerebral palsy were studied and many showed disruption of cell signalling and inflammatory pathways, as seen in some children with autism.
“The results showed that the neurological or signalling pathways being disrupted in children with cerebral palsy overlap with those disruptions seen in autism,” says Dr van Eyk. “This supports a common biological change in both cerebral palsy and autism. Autism and cerebral palsy do sometimes co-exist, which further underlines common causation in some individuals.”
This is the latest in a series of studies from the University of Adelaide which have found increasing numbers of genetic mutations that are the likely cause of cerebral palsy. Using this data together with existing DNA sequencing results increases the proportion of individuals with a likely genetic cause to around 25%.
The University’s Cerebral Palsy Research Group is led by Emeritus Professor Alastair MacLennan and Professor Jozef Gecz, Channel 7 Children’s Research Foundation Chair for the Prevention of Childhood Disability. They are leading the world in discovering an increasing genetic basis to cerebral palsy.
“This research continues to refute the historical assumption that cerebral palsy is often due to difficulties at birth,” says Professor MacLennan.

University of Adelaidewww.adelaide.edu.au/news/news99822.html

Chemical octopus catches sneaky cancer clues, trace glycoproteins

Cancer drops sparse chemical hints of its presence early on, but unfortunately, many of them are in a class of biochemicals that could not be detected thoroughly, until now.
Researchers at the Georgia Institute of Technology have engineered a chemical trap that exhaustively catches what are called glycoproteins, including minuscule traces that have previously escaped detection.
Glycoproteins are protein molecules bonded with sugar molecules, and they’re very common in all living things. Glycoproteins come in myriad varieties and sizes and make up important cell structures like cell receptors. They also wander around our bodies in secretions like mucus or hormones.
But some glycoproteins are very, very rare and can serve as an early signal, or biomarker, indicating there’s something wrong in the body – like cancer. Existing methods to reel in glycoproteins for laboratory examination are relatively new and have had big holes in their nets, so many of these molecules, especially those very rare ones produced by cancer, have tended to slip by.
 “These tiny traces are critically important for early disease detection,” said principal investigator Ronghu Wu, a professor in Georgia Tech’s School of Chemistry and Biochemistry. “When cancer is just getting started, aberrant glycoproteins are produced and secreted into body fluids such as blood and urine. Often their abundances are extremely low, but catching them is urgent.”
This new chemical trap, which took Georgia Tech chemists several years to develop and is based on a boronic acid, has proven extremely effective in lab tests including on cultured human cells and mouse tissue samples.
“This method is very universal,” said first author Haopeng Xiao, a graduate research assistant. “We get over 1,000 glycoproteins in a really small lab sample.”
In comparison tests with existing methods, the chemical trap, a complex molecular construction reminiscent of an octopus, captured exponentially more glycoproteins, especially more of those trace glycoproteins.
Wu, Xiao and Weixuan Chen, a former Georgia Tech postdoctoral researcher, who was also first author of the study alongside Xiao.
For chemistry whizzes, here’s a short summary of how the researchers made the octopus. They took a good thing and doubled then tripled down on it.
Those who recall high school chemistry class may still know what boric acid is, as do people who use it to kill roaches. Its chemical structure is an atom of boron bonded with three hydroxyl groups (H3BO3).
Boronic acids are a family of organic compounds that build on boric acid. There are many members of the boronic acid family, and they tend to bond well with glycoproteins, but their bonds can be less reliable than needed.
“Most boronic acids let too many low-abundance glycoproteins get away,” Wu said. “They can catch glycoproteins that are in high abundance but not those in low abundance, the ones that tell us more valuable things about cell development or about human disease.”
But the Georgia Tech chemists were able to leverage the strengths of boronic acids to develop a glycoprotein capturing method that works exceptionally well.
First, they tested several boronic acid derivatives and found that one called benzoboroxole strongly bound with each sugar component on the glycopeptide. (“Peptide” refers to the basic chemical composition of a protein.) 
Then they stitched many benzoboroxole molecules together with other components to form a "dendrimer," which refers to the resulting branch- or tentacle-like structure. The finished large molecule resembled an octopus ready to go after those sugar components.
In its middle, similarly positioned to an octopus’s head, was a magnetic bead, which acted as a kind of handle. Once the dendrimer caught a glycoprotein, the researchers used a magnet to grab the bead and pull out their chemical octopus along with its ensnared glycopeptides (e.g. glycoproteins).
“Then we washed the dendrimer off with a low pH solution, and we had the glycoproteins analysed with things like mass spectrometry,” Wu said.
The researchers have some ideas about how medical laboratory researchers could make practical use of the new Georgia Tech method to detect odd biomolecules emitted by cancer, such as antigens. For example, the chemical octopus could improve detection of prostate-specific antigens (PSA) in prostate cancer screenings.
“PSA is a glycoprotein. Right now, if the level is very high, we know that the patient may have cancer, and if it’s very low, we know cancer is not likely,” Wu said. “But there is a gray area in between, and this method could lead to much more detailed information in that gray area.”
The researchers also believe that developers could leverage the chemical invention to produce targeted cancer treatments. Immune cells could be trained to recognize the aberrant glycoproteins, track down their source cancer cells in the body and kill them.

Georgia Institute of Technologywww.news.gatech.edu/2018/05/04/chemical-octopus-catches-sneaky-cancer-clues-trace-glycoproteins

Leukaemia: protective role of Y chromosone gene discovered

Researchers have found that UTY, a gene on the Y chromosome, protects male mice lacking the tumour-suppressing UTX gene on the X chromosome from developing acute myeloid leukaemia
Researchers at the Wellcome Sanger Institute and the University of Cambridge found that this Y-chromosome gene protects against the development of Acute Myeloid Leukaemia (AML) and other cancers.
The study investigated how loss of the X-chromosome gene UTX, which is known to be mutated in many tumours, hastens the development of AML. However, they found that UTY, a related gene on the Y chromosome, protected male mice lacking UTX from developing AML. The authors then show that in AML and in several other human cancers types, loss of UTX is accompanied by loss of UTY, confirming that the cancer-suppressing role of UTY extends beyond AML.
Acute myeloid leukaemia is an aggressive blood cancer that affects people of all ages. It develops in cells in the bone marrow and leads to life-threatening infections and bleeding. Mainstream AML treatments have remained unchanged for decades.
Women have two X chromosomes whereas men have one X and one Y chromosome. The X and Y chromosomes share many genes, but a small number of genes, including UTY, are only found on the Y chromosome. These Y-specific genes were thought to contain the genetic information required for male sexual characteristics, but were not known to have other roles. The discovery of this new role changes the way the Y chromosome is viewed and improves understanding of how AML and other cancers develop.

“This is the first Y chromosome-specific gene that protects against AML. Previously it had been suggested that the only function of the Y chromosome is in creating male sexual characteristics, but our results indicate that the Y chromosome could also protect against AML and other cancers.”
Dr Malgorzata Gozdecka, the first author on the study from the Wellcome Sanger Institute

“It is known that men often lose the Y chromosome from their cells as they age, however the significance of this was unclear. Our study strengthens the argument that loss of the Y chromosome can increase the risk of cancer and describes a mechanism for how this may happen.”
Professor Brian Huntly, joint project leader from the Wellcome-MRC Cambridge Stem Cell Institute, and Consultant Haematologist, at Cambridge University Hospitals NHS Trust

In their study, researchers studied the UTX gene in human cells and in mice to try to understand its role in AML. In addition to their discovery that UTY acts as a tumour suppressor gene, the scientists found a new mechanism for how loss of UTX leads to AML. They discovered that UTX acts as a common scaffold, bringing together a large number of regulatory proteins that control access to DNA and gene expression, a function that can also be carried out by UTY. When UTX/UTY are missing, these proteins can’t regulate gene expression correctly and cancer growth becomes more likely.

“Treatments for AML have not changed in decades and there is a large unmet need for new therapies. This study helps us understand the development of AML and gives us clues for developing new drug targets to disrupt leukaemia-causing processes. We hope this study will enable new lines of research for the development of previously unforeseen treatments and improve the lives of patients with AML.”
Dr George Vassiliou, joint project leader from the Wellcome Sanger Institute, Wellcome-MRC Cambridge Stem Cell Institute and Consultant Haematologist at Cambridge University Hospitals NHS Trust.

“Survival rates for AML remain tragically low, with current treatment that involves intensive chemotherapy, often combined with a stem cell transplant, only curing a small proportion of patients. This important research helps build a fuller picture of what goes wrong genetically as this highly aggressive leukaemia develops. Understanding this process is key to developing targeted drugs for AML, allowing us to move away from gruelling and often ineffective chemotherapy-based treatments.”

Wellcome Sanger Institutewww.sanger.ac.uk/news/view/leukaemia-protective-role-y-chromosone-gene-discovered

Examining links between breast cancer, second primary cancer and inherited genetic mutations

Rates of inherited mutations in genes other than BRCA1/2 are twice as high in breast cancer patients who have had a second primary cancer – including, in some cases, different types of breast cancer – compared to patients who have only had a single breast cancer. But the rates of these mutations were still found to be low overall, meaning it’s difficult to assess whether and how these individual mutations may drive the development of cancer. The study from the Basser Center for BRCA in the Abramson Cancer Center of the University of Pennsylvania also investigated the use of polygenic risk scores – which have recently been added to some commercial clinical multiplex genetic testing panels. Kara N. Maxwell, MD, PhD, an instructor of Hematology-Oncology and the study’s lead author, presented the findings at the 2018 American Society of Clinical Oncology Annual.
Genetic testing can help identify patients have a genetic predisposition that puts them at risk for developing cancer. Recently, new therapies called PARP inhibitors have been FDA approved to specifically target cancers caused by certain mutations – such as BRCA1/2, which carry a lifetime breast cancer risk of as much as 85 percent and 50 percent for ovarian cancer, as well as higher risks of pancreatic, prostate and other cancers.
“We need to gain a better understanding of why patients who have multiple cancers may be susceptible to them, and that work needs to go beyond the common genes we’re already been looking at,” Maxwell said.
The team – led by Susan M. Domchek, MD, executive director of the Basser Center for BRCA, and Katherine L. Nathanson, MD, deputy director of the Abramson Cancer Center, specifically looked at patients who did not have a BRCA1/2 mutation and tested them for a panel of 15 different genetic mutations. They evaluated 891 patients who had a second primary cancer – breast or otherwise – after initial breast cancer and compared them to 1,928 who only had a single breast cancer. About eight percent of patients who had second primary cancers had mutations, compared to just four percent of patients from the single cancer cohort. The current threshold for whether or not genetic testing is recommended is five percent.
“Our data show that patients who have had multiple primary cancers should undergo genetic testing, and likely this holds true for a number of other types of second cancer,” Maxwell said. “However, the overall numbers are still low, which shows the level of uncertainty that still exists and highlights the need for further research.”
The research also evaluated polygenic risk scores, a somewhat controversial metric recently added to some commercial clinical multiplex genetic testing panels. Polygenic risk scores are determined by how many single nucleotide polymorphisms (SNPs) a person has. SNPs are common variants with smaller effect sizes, and if a patient has multiple of certain SNPs, they may be at a similar increased for cancer a as patients with a single rare mutation.
“Our study does not provide strong evidence of higher polygenic risk scores in patients with more than one breast cancer,” but many more patients will need to be studied to confirm this,” Maxwell said.

Penn Medicinewww.pennmedicine.org/news/news-releases/2018/june/beyond-brca-examining-links-between-breast-cancer-second-primary-cancer-inherited-genetic-mutations
 

Dicer cuts down on fats

The enzyme Dicer cleaves long precursors into short RNA molecules called microRNAs. A new study reveals how Dicer enhances energy metabolism and reduces levels of fat storage in macrophages, thus slowing the progression of atherosclerosis.
Atherosclerosis is one of the primary causes of premature death in modern societies. The condition is characterized by the deposition of fat-soluble molecules – principally cholesterol and triglycerides – on the inner walls of major blood vessels. This process triggers vascular inflammation and the formation of atherosclerotic plaques, which ultimately lead to narrowing of the arteries, thus impeding the flow of blood. Cells called macrophages are responsible for the uptake and disposal of the fatty deposits that induce plaque formation. However, depending on how they have been activated, macrophages can play an insidious role in the development of atherosclerosis. Inflammatory activation promotes inflammation, while ‘alternatively activated’ macrophages suppress inflammation reactions. The latter degrade triglycerides by means of fatty acid oxidation, but if this pathway operates sub-optimally – due to local inflammation, for example – they accumulate the engulfed fats, thus contributing to plaque development and increasing the risk of blood vessel blockage. A team of researchers in the Institute for Prophylaxis and Epidemiology of Cardiovascular Diseases at the LMU Medical Center, led by Professor Andreas Schober, has now shown that the enzyme Dicer plays an important role in the breakdown of triglycerides in alternatively activated macrophages.
Dicer slices long precursor RNAs into short snippets, which are known as microRNAs (miRNAs). miRNAs make a significant contribution to the regulation of gene activity. By binding to complementary nucleotide sequences in messenger RNAs (mRNAs), miRNAs prevent the synthesis of specific proteins. The Munich researchers used a mouse model system to study the impact of functional deletion of the Dicer gene in macrophages on energy metabolism. “We found that lack of Dicer in macrophages impairs their capacity for oxidative degradation of triglycerides. As a result, they accumulate more fat and develop into what are called foam cells“, Schober explains. Foam cells die at a higher rate than normal macrophages, which stimulates progression of atherosclerosis.
Schober and his colleagues went on to show that the effects of Dicer knockout on macrophage function are attributable to the loss of a single microRNA, named miR-10a, which is required for normal regulation of energy metabolism in these cells, and boosts the oxidative breakdown of the fatty acids in triglycerides. In addition, they identified the relevant target of miR-10a as the mRNA that codes for the ligand-dependent nuclear co-repressor protein (Lcor). “When the interaction between the two RNAs” (which reduces levels of the Lcor protein) “is inhibited, progression of atherosclerosis is accelerated, as in the case of the knockout of Dicer,” says Schober.
The discovery of this specific regulation of fatty acid metabolism in macrophages could lead to a novel therapeutic strategy for the treatment of atherosclerosis.

LMU Medical Center
www.en.uni-muenchen.de/news/newsarchiv/2018/schober_dicer.html

Organoid profiling personalizes treatments for pancreatic cancer

Patient-derived organoids, hollow spheres of cells cultured from tumours, can quickly and accurately predict how patients with pancreatic cancer respond to a variety of treatments, facilitating a precision-medicine approach to the deadly disease. The ability to use organoids as a treatment tool was investigated by an international team of researchers led by Dr. David Tuveson, M.D., Ph.D., Cold Spring Harbor Laboratory (CSHL) Professor and Chief Scientist for The Lustgarten Foundation.
“We’ve identified an approach to prioritize treatment strategies for pancreas cancer patients, with the goal of giving them the best shot at survival and the best shot at a good quality of life,” says Dr. Hervé Tiriac, a researcher in Tuveson’s lab and first author of the paper published today in Cancer Discovery.
With only 8 percent of patients surviving 5 years beyond their diagnosis, pancreatic cancer is one of the deadliest cancer types. Currently, surgical removal of the cancerous tissue is the only effective treatment, but because the disease progresses so quickly, only 15 percent of patients are eligible for the procedure. Surgery-ineligible patients can be treated with drugs or chemotherapy, but patient response is highly varied and there is no good method to determine which treatment is best for any given patient.
For several years, Tuveson has been honing organoid technology to improve research into the disease. Aside from taking only as little as six weeks to grow, a major advantage of organoids is that they can be derived from patients with even very advanced pancreatic cancer, using tiny biopsies.
In this latest development, the Tuveson team generated a library of 66 organoids derived from pancreatic ductal adenocarcinoma (PDAC) tumor specimens at various stages of the disease. The researchers demonstrated that the organoids provide an effective precision-medicine “pharmacotyping,” or drug-testing, pipeline. To do this, “we culture the organoid from the patient’s cancer and then test all possible standard-of-care drugs as well as experimental drugs,” Tiriac explains.
The team assessed RNA levels in individual organoids—a way to measure gene activity—to predict the sensitivity of an organoid to the five chemotherapies currently administered to pancreatic cancer patients. They found that three so-called “signatures” of gene activity in the organoids correctly identified patients who had responded well to these drugs. “The signatures should enable physicians to choose the best initial chemotherapy treatment for pancreatic cancer,” Tuveson says.
Tuveson and his team plan to further refine the gene signatures through additional experiments, and to test in clinical trials the ability of signatures found in organoids to predict the responses of pancreatic cancer patients.

Cold Spring Harbour Laboratory
www.cshl.edu/organoid-profiling-personalizes-treatments-for-pancreatic-cancer/

Blood mutations could contaminate genetic analyses of tumours

Genetic mutations in blood cells that have made their way into tumours could be red herrings that mislead physicians looking for genetic changes in tumours that are helping to drive the cancer. This finding is significant because physicians could make misinformed treatment decisions.
University of North Carolina Lineberger Comprehensive Cancer Center researchers and colleagues will report findings at the 2018 American Society of Clinical Oncology Annual Meeting on Monday, June 4, that show that blood cell mutations accounted for as many as 8 percent of the mutations identified in large-scale genetic sequencing efforts at two major academic centres.
“Next-generation sequencing of solid tumours is intended to identify acquired mutations within tumour tissue,” said the study’s first author Catherine C. Coombs, an associate member of UNC Lineberger and an assistant professor in the UNC School of Medicine Division of Hematology/Oncology. “The identification of acquired mutations in blood cells could lead to errors in interpretation of sequencing results.”
For the study, researchers reviewed data from patients with solid tumour cancers who had genetic sequencing tests performed by Foundation Medicine as part of their routine clinical care at the N.C. Cancer Hospital and the Moffitt Cancer Center between 2013 and 2017. They also analysed sequencing results for blood samples. A subset of patients at the N.C. Cancer Hospital had their tumours and their blood sequenced through UNCseq, a genetic sequencing clinical trial run by UNC Lineberger researchers. For patients at Moffitt Cancer Center, they compared Foundation Medicine results to sequencing results from banked blood samples.
The researchers analysed the data to identify mutations more commonly seen in blood cells. They found that “clonal haematopoiesis,” which are acquired mutations in blood cells, accounted for 8 percent of the mutations.
“The presence of clonal haematopoiesis mutations on next-generation sequencing reports from solid tumour biopsies can confound assay interpretation with the risk of misguided application of targeted therapies,” Coombs said.
Researchers say further work must be done to develop standard processes for differentiating mutations that occur in the blood versus the tumour in order to ensure accuracy in the tests for physicians who are using the sequencing results to choose personalized treatments for patients. In addition, the study shows an advantage to “paired” sequencing tests, which evaluate mutations in both the blood and the tumour.

University of North Carolina Lineberger Comprehensive Cancer Center
unclineberger.org/news/mutations-could-contaminate-genetic-analyses

High-sensitivity troponin test reduces risk of future heart attack

A blood test that measures the presence of heart-specific proteins called troponins is used by emergency clinics to diagnose myocardial infarction in patients with chest pain. For the past few years a newer laboratory method has been used at most hospitals in Sweden that is ten times more sensitive than the conventional troponin test. The high-sensitivity troponin test can discover heart attacks earlier so that treatment can commence, which is thought to improve the patients’ prognosis.
"But there is a lack of larger studies examining whether the high-sensitivity troponin test is of any significance for patients with newly diagnosed myocardial infarction in terms of survival or the risk of another heart attack," says study leader Dr. Martin Holzmann, associate professor of epidemiology at Karolinska Institutet’s Department of Medicine in Solna and physician at Karolinska University Hospital.
The study included all patients in Sweden who had had their first heart attack between 2009 and 2013. This gave a study population of almost 88,000 patients, 40,000 of whom had been diagnosed using the high-sensitivity troponin test and just over 47,000 using the conventional troponin test.
The researchers found that five per cent more myocardial infarctions were being diagnosed in hospitals that used the high-sensitivity troponin test. A year after the heart attack was registered there was no difference in mortality between the two groups, although the number of new heart attacks was lower in the group that had been diagnosed using the high-sensitivity troponin test.
"This surprised us," says Dr. Holzmann. "We didn’t think that the more sensitive test would affect the risk of future heart attacks."
The use of coronary angiography and balloon angioplasty was 16 and 13 per cent more common, respectively in the patients diagnosed with the high-sensitivity troponin test. In the USA, where the new test was not approved until 2017, there are fears that the more sensitive methods can entail a large increase in the number of examinations with no benefit to the patients.
"The increase we observed in our study was less than expected, which means that the high-sensitivity troponin test has enabled doctors to single out the patients who benefit from such intervention. We found no differences in medication between the two groups, so the differences in prognosis with fewer new heart attacks could be attributed to the fact that more coronary angiography and balloon dilation procedures have been performed on the right patients," says Dr. Holzmann, who also believes that the study supports the idea that the handful of hospitals in Sweden that still do not use the high-sensitivity troponin test should start to do so.

MedicalXpress
medicalxpress.com/news/2018-06-high-sensitivity-troponin-future-heart.html