Tag: heart failure

Categories : Cardiovascular DiseaseTags :

Tirzepatide Found to Protect against Worsening Heart Failure

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Right side heart failure. Credit: Scientific Animations CC4.0

The diabetes drug tirzepatide can reduce the risk of death or worsening heart failure for patients with heart failure, preserved heart pump function and obesity, new research from UVA Health reveals.

Researchers tested the GLP-1 receptor agonist in the SUMMIT clinical trial, where a total of 731 patients with diastolic heart failure and a body mass index (BMI) of 30 or above were randomised to receive injections of either tirzepatide or a harmless placebo. The researchers then followed the patients for a median period of two years. Tirzepatide is also prescribed as a weight loss drug in certain countries.

During that time, 56 placebo recipients died or suffered worsening heart failure, compared with only 36 of those receiving tirzepatide. Participants taking tirzepatide also lost 11.6% of their body weight.

“This class of drugs continue to show benefits far beyond weight loss,” said researcher Christopher Kramer, MD, chief of UVA Health’s Division of Cardiovascular Medicine. “This drug will become an important part of the armamentarium for patients with obesity-related heart failure and preserved heart function.”

Obesity and heart failure

Obesity is a major contributing factor to heart failure, so Kramer and his collaborators in the SUMMIT trial wanted to see if tirzepatide, a weight-loss drug already approved by the federal Food and Drug Administration, could help. 

The trial found that tirzepatide offered substantial benefits for managing diastolic heart failure, reducing deaths, preventing hospitalizations and generally benefiting recipients’ health and quality of life. For example, recipients saw improvements in how far they could walk in six minutes, as well as substantial decreases in a biological indictor used to measure inflammation and predict risk of serious cardiovascular events.

Side effects seen in the tirzepatide group consisted of gastrointestinal issues such as nausea and diarrhea, and these were mostly mild or moderate, the researchers reported Saturday at a meeting of the American Heart Association in Chicago.

Tirzepatide Findings

Kramer, a cardiovascular imager, also led a magnetic resonance imaging substudy looking at how tirzepatide affected recipients’ heart structure and function. The researchers found beneficial reductions in both left ventricular mass (weight of the heart) and in the amount of surrounding fat tissue. The reduction in LV mass correlated with the reduction in body weight, as well as with decreases in left ventricular volumes.

“This drug is reversing the abnormal properties of the heart brought on by obesity,” Kramer said. “There is much more to these drugs than weight loss alone.”

The findings from these studies by Kramer and his fellow researchers from SUMMIT are being published simultaneous with the American Heart meeting in Chicago in four separate manuscripts, including the New England Journal of Medicine, Nature Medicine, Circulation and the Journal of the American College of Cardiology.

Source: University of Virginia Health System

Categories : Cardiovascular Disease Mental HealthTags :

Beta Blockers may Also Cause Depression for Cardiac Patients

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Photo by Towfiqu Barbhuiya on Unsplash

Patients who have had a heart attack are typically treated using beta blockers. According to a Swedish study conducted earlier this year, this drug is unlikely to be needed for those heart patients who have a normal pumping ability. Now a sub-study at Uppsala University shows that there is also a risk that these patients will become depressed by the treatment.

“We found that beta blockers led to slightly higher levels of depression symptoms in patients who had had a heart attack but were not suffering from heart failure. At the same time, beta blockers have no life-sustaining function for this group of patients,” says Philip Leissner, a doctoral student in cardiac psychology and the study’s first author. The study was published in European Heart Journal Acute Cardiovascular Care.

Beta blockers are drugs that block the effects of adrenaline on the heart and have been used for decades as a basic treatment for all heart attack patients. In recent years, their importance has started to be questioned as new, successful treatments have begun to be developed. This is mainly the case for heart attack patients who do not suffer from heart failure.

The researchers wanted to look at the side effects of beta blockers, that is, whether they affect anxiety and depression levels. This is because older research and clinical experience suggests that beta blockers are linked to negative side effects such as depression, difficulty sleeping and nightmares.

Earlier this year, a major national study was conducted in Sweden, which found that those who received beta-blocking drugs were not protected from relapse or death compared to those who did not receive the drug. Leissner and his colleagues based their research on these findings and conducted a sub-study. It ran from 2018 to 2023 and involved 806 patients who had had a heart attack but no problems with heart failure. Half were given beta blockers and the other half were not. About 100 of the patients receiving beta blockers had been taking them since before the study, and the researchers observed more severe symptoms of depression in them.

“Most doctors used to give beta blockers even to patients without heart failure, but as the evidence in favour of doing so is no longer so strong, this should be reconsidered. We could see that some of these patients appear to be more at risk of depression. If the drug doesn’t make a difference to their heart, then they are taking it unnecessarily and at risk of becoming depressed,” adds Leissner.

Source: Uppsala University

Categories : Cardiovascular DiseaseTags :

Immunotherapy Blocks Scarring, Improves Cardiac Function in Heart Failure

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Right side heart failure. Credit: Scientific Animations CC4.0

A new study from Washington University School of Medicine in St. Louis suggests that a type of immunotherapy also may be an effective treatment strategy for heart failure by using an FDA-approved drug to block the signalling protein IL-1 beta. The study is published in Nature.

After a heart attack, viral infection or other injury to the heart, scar tissue often forms in the heart muscle, where it interferes with the heart’s normal contractions and plays a leading role in heart failure, a chronic condition which can only be slowed, not cured.

Studying human tissue samples as part of the new study, the researchers identified a type of fibroblast cell in the heart as the main culprit responsible for the formation of scar tissue in heart failure. To see if they could prevent scar formation, the scientists turned to mouse models of heart failure that have the very same type of fibroblasts. They used a therapeutic monoclonal antibody that blocks the formation of this harmful type of fibroblast, and succeeded in reducing the formation of scar tissue and improving heart function in the mice.

“After scar tissue forms in the heart, its ability to recover is dramatically impaired or impossible,” said cardiologist and senior author Kory Lavine, MD, PhD, a professor of medicine in the Cardiovascular Division at WashU Medicine. “Heart failure is a growing problem in the US and globally, affecting millions of people. Current treatments can help relieve symptoms and slow the progression, but there is a tremendous need for better therapies that actually stop the disease process and prevent the formation of new scar tissue that causes a loss of heart function. We are hopeful our study will lead to clinical trials investigating this immunotherapy strategy in heart failure patients.”

Fibroblasts have many roles in the heart, and parsing out the differences between various populations of these cells has been challenging. Some types of fibroblasts support the heart’s structural integrity and maintain good blood flow through the heart’s blood vessels, while others are responsible for driving inflammation and the development of scar tissue. Only recently, with the wide availability of the most advanced single cell sequencing technologies, could scientists peg which groups of cells are which.

“These various types of fibroblasts highlight newly recognised opportunities to craft treatment strategies that specifically block the type of fibroblasts that promote scarring and protect fibroblasts that maintain the structure of the heart, so the heart doesn’t rupture,” Lavine said. “Our research suggests that the fibroblasts that promote scarring in the injured heart are very similar to fibroblasts associated with cancer and other inflammatory processes. This opens the door to immunotherapies that potentially can stop the inflammation and resulting scar tissue.”

The research team, co-led by Junedh Amrute, a graduate student in Lavine’s lab, used genetic methods to demonstrate that a signaling molecule called IL-1 beta was important in a chain of events driving fibroblasts to create scar tissue in heart failure. With that in mind, they tested a mouse monoclonal antibody that blocks IL-1 beta and found beneficial effects in the mouse hearts. The mouse monoclonal antibody was provided by Amgen, whose scientists were also co-authors of the study. Monoclonal antibodies are proteins manufactured in the lab that modulate the immune system. The treatment reduced the formation of scar tissue and improved the pumping capacity of the mouse hearts, as measured on an echocardiogram.

At least two FDA-approved monoclonal antibodies, canakinumab and rilonacept, can block IL-1 signalling. These immunotherapies are approved to treat inflammatory disorders such as juvenile idiopathic arthritis and recurrent pericarditis, which is inflammation of the sac surrounding the heart.

One of these antibodies also has been evaluated in a clinical trial for atherosclerosis, a buildup of plaque that hardens the arteries. The trial, called CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcome Study), showed a benefit for study participants with atherosclerosis.

“Even though this trial was not designed to test this treatment in heart failure, there are hints in the data that the monoclonal antibody might be beneficial for patients with heart failure,” Lavine said. “Secondary analyses of the data from this trial showed that the treatment was associated with a sizable reduction in heart failure admissions compared with standard care. Our new study may help explain why.”

Even so, the IL-1 antibody used in the CANTOS study had some side effects, such as increased risk of infection, that could perhaps be reduced with a more targeted antibody that specifically blocks IL-1 signaling in cardiac fibroblasts, according to the researchers.

“We are hopeful that the combination of all of this evidence, including our work on the IL-1 beta pathway, will lead to the design of a clinical trial to specifically test the role of targeted immunotherapy in heart failure patients,” Lavine said.

Source: Washington University School of Medicine

Categories : Cardiovascular DiseaseTags :

A New Heart Failure Treatment Targets Abnormal Hormone Activity

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Right side heart failure. Credit: Scientific Animations CC4.0

Scientists have discovered a potential new treatment for heart failure with preserved ejection fraction (HFpEF), a type of heart disease that is notoriously difficult to treat. The diseased heart cells were found to have high levels of glucagon activity, a pancreatic hormone that raises blood glucose levels. The scientists then demonstrated that a drug that blocks the hormone’s activity can significantly improve heart function.

In heart failure, which is considered a global pandemic, the heart can no longer pump blood effectively. Globally, an estimated 64 million people live with this condition with HFpEF accounting for around half of the cases.

In HFpEF, the heart can pump normally but its muscles are too stiff to relax to re-fill the chambers with blood properly. It is often seen in older adults and people with multiple risk factors including high blood pressure (hypertension), obesity and diabetes. They typically have symptoms such as shortness of breath, fatigue and reduced ability to exercise. This is unlike heart failure with reduced ejection fraction (HFrEF), where heart muscle is weakened and pumping volume reduced.

There have been studies on how the heart is stressed by hypertension and metabolic diseases associated with obesity, such as diabetes, but these have been done in isolation of each other. This latest study, which was published in Circulation Research, addresses this gap by taking into account both stressors, revealing for the first time, the molecular pathway that contributes to HFpEF progression.

In pre-clinical studies, the team of scientists, which included collaborators from the University of Cincinnati College of Medicine, University of California Los Angeles, University of Toronto and University of North Carolina School of Medicine, investigated how stress from hypertension affected lean hearts versus diabetic/obese ones. In their findings, the lean models developed heart failure with reduced ejection fraction (HFrEF), typically observed in hypertensive patients. The obese models however, developed heart failure with preserved ejection fraction (HFpEF), proving that a combination of stressors give rise to the disease and providing a good model for further studies.

Using advanced single-cell RNA-sequencing technologies, the scientists were then able to study the expression of every detected gene in every single heart cell, allowing them to uncover specific genetic variations in cells associated with HFpEF. The scientists found that in the obese models, the most active genes were the ones driving the activity of glucagon.

Professor Wang Yibin, Director of the Cardiovascular & Metabolic Disorders Programme at Duke-NUS and senior author of the study, said:

“Under stress conditions such as high blood pressure and metabolic disorders like obesity and diabetes, we found that glucagon signalling becomes excessively active in heart cells. This heightened activity contributes to the development of heart failure with preserved ejection fraction (HFpEF) by increasing heart stiffness and impairing its ability to relax and fill with blood.”

The team then tested a drug that blocks the glucagon receptor in a pre-clinical model of HFpEF and found significant improvements in heart function, including reduced heart stiffness, enhanced relaxation, improved blood filling capacity and overall better heart performance.

Assistant Professor Chen Gao from the Department of Pharmacology, Physiology and Neurobiology at the University of Cincinnati College of Medicine; and the study’s first author, said:

“Our study shows strong evidence that a glucagon receptor blocker could work well to treat HFpEF. Repurposing this drug, which is already being tested in clinical trials for diabetes, could bypass the lengthy drug development process and provide quicker and more effective relief to millions of heart patients.”

Professor Patrick Tan, Senior Vice-Dean for Research at Duke-NUS, commented:

“With our ageing population, there will likely be more patients with multiple conditions, including heart failure, diabetes and hypertension, presenting a significant challenge to health systems. Uncovering the synergistic impact of such illnesses and their underlying mechanisms is key to better understanding the complex process of heart failure and developing an effective treatment for the disease.”  

The researchers hope to work with clinical partners to conduct clinical trials to test the glucagon receptor blocker in humans with HFpEF. If these succeed, it could become one of the first effective treatments for this challenging condition, significantly improving the quality of life for millions worldwide.

Source: Duke University

Categories : Cardiovascular DiseaseTags :

SA Heart Congress Unites Cardiologists for Better Care

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The SA Heart Annual Congress will take place from 8–10 November at the Sandton Convention Centre, Johannesburg. The three-day Congress, themed ‘Cardiology Connections,’ will promote collaboration and dialogue among local and international Cardiology professionals. The congress offers a unique platform for experts, practitioners, and researchers worldwide to share insights on the latest advancements and challenges in cardiovascular medicine.

The dynamic programme includes keynote speeches, panel discussions, workshops, and networking sessions. The agenda covers a comprehensive range of cardiology topics, designed to provide practical knowledge and inspire innovation in the field. Attendees will gain critical insights into the latest developments that have the potential to enhance patient care.

“We are excited to welcome a distinguished international and local faculty,” says Dr Ahmed Vachiat, SA Heart Congress Convenor. “At the core of SA Heart is the mission to advance cardiovascular care through education, research, and advocacy. By connecting healthcare professionals from across sectors, this Congress will drive forward our vision of improving cardiovascular care for all in South Africa. We are also grateful for the invaluable support of our local experts, whose contributions consistently uphold international standards of excellence.”

A significant focus this year is strengthening connections among various special interest groups, including the Society of Cardiovascular Interventions (SASCI), Cardiovascular Imaging Society of South Africa (CISSA), Cardiovascular Arrhythmia Society of South Africa (CASSA), Heart Failure Association of South Africa (HEFFSA), Intervention Society of Cardiovascular Allied Professionals (ISCAP), South African Society of Cardiovascular Research (SASCAR), and the Paediatric Society of Cardiology (PCSSA).

Joint sessions and interdisciplinary programmes will enable these groups to work together to enhance healthcare delivery for all patients in need of cardiac intervention and treatment. Workshops and scientific sessions will feature innovative learning approaches aimed at facilitating knowledge exchange and professional growth.

A cardiovascular team from the Mayo Clinic – Prof Vuyi Nkomo (Imaging Cardiologist), Prof Sorin Pislaru (Chair, Structural Heart Disease), and Dr Juan Crestanello (Chair, Cardiothoracic Surgery) – will conduct an echocardiography workshop and contribute to various specialist workshops on Friday morning, November 8th.

Dr Thomas Alexander, a respected interventional cardiologist based in India, will share insights on establishing STEMI networks in South Africa. Prof Stylianos Pyxaras from Germany and Dr Andrew Ludwiniec from the UK will discuss chronic total occlusions and complex coronary interventions. Prof Azfar Zaman and Prof Roy Gardner also from the UK and leaders in their field, as well as Prof Thierry Lefevre from France, will join esteemed local experts in addressing important cardiovascular topics.

A new addition to this year’s programme is the Imbizo on Rheumatology and Cardiac diseases. Over 40 Abstracts have been submitted and research sessions guided by SASCAR will be keeping delegates up to date with the latest in the field of Cardiology.

In addition, an excellent parallel paediatric programme will feature global leaders, Prof Krishna Kumar, from India and Prof McDaniel from the USA, with a pre-congress workshop and highly interactive sessions that will incorporate insights from local experts.

“This year, a Heartbeat Stage will feature insightful talks, engaging presentations, and a special networking address,” says Dr Vachiat. “We are honoured to have Dr Imtiaz Sooliman from Gift of the Givers, who will share his thoughts on ‘Connecting Hearts and Social Responsibility’.”

For more information, visit SA Heart.

Categories : Cardiovascular DiseaseTags :

Finerenone Reduces Worsening Heart Failure and Cardiovascular Death in Clinical Trial

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Right side heart failure. Credit: Scientific Animations CC4.0

Finerenone reduced the composite of total first and recurrent heart failure (HF) events (hospitalisations for HF or urgent HF visits) and cardiovascular death in patients with HF and mildly reduced or preserved ejection fraction, according to an international clinical trial led by investigators from Brigham and Women’s Hospital.

Heart failure events and cardiovascular death were less common in the finerenone group than in the placebo group. Overall, the rate of serious adverse events was similar across the groups, but rates of hyperkalaemia were higher for the group taking finerenone. Results were presented at the European Society of Cardiology Congress 2024 and published simultaneously in the New England Journal of Medicine.

“We saw benefit regardless of the ejection fraction and even in patients who were on other approved therapies,” said trial principal investigator and corresponding author Scott Solomon, MD, the director of the Clinical Trials Outcomes Center at Mass General Brigham and the Edward D. Frohlich Distinguished Chair at Brigham and Women’s Hospital. “This drug represents a new drug class that may become a pillar of therapy for this disease.”

HF is the progressive decline in the heart’s ability to fill with and pump blood. It affects over 60 million people worldwide. Approximately half of all people living with HF have mildly reduced or preserved left ventricular ejection fraction, a condition with limited treatment options. These findings suggest that the non-steroidal mineralocorticoid receptor antagonist finerenone could represent a new therapeutic option for patients.

The FINEARTS-HF trial, funded by Bayer, assigned 6000 patients to receive either finerenone or placebo in addition to their existing therapies. The trial’s limitations include few Black patients, although the percentage of Black patients was proportional to their regional population. “Our group continues to study novel therapies for heart failure,” Solomon said. “There’s huge residual risk in these patients and so more room for new therapies.“

Source: Brigham and Women’s Hospital

Categories : Cardiovascular DiseaseTags :

Study Uncovers Connections Between Obesity and Heart Failure at the Cellular Level

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Right side heart failure. Credit: Scientific Animations CC4.0

A new small study led by Johns Hopkins Medicine researchers recently published in the journal Nature Cardiovascular Research has revealed the impact of obesity on muscle structure in patients having a form of heart failure called heart failure with a preserved ejection fraction (HFpEF). They observed swollen mitochondria, lipid droplets and tattered muscle fibre bundles, all independent of diabetes status.

According to the Journal of Cardiac Failure, HFpEF represents more than half of all heart failure world-wide. Originally, this form of heart disease was associated with hypertension and along with this, excess muscle growth (hypertrophy) to help counter the pressures. Over the past two decades, HFpEF is occurring more often in patients with severe obesity and diabetes according to the Journal of the American College of Cardiology. However, there are still very few effective HFpEF therapies, and a challenge in developing therapies has been the lack of studies in human heart tissue to determine exactly what is abnormal. As hospitalisation and death rates in HFpEF patients are quite high, (30–40% over 5 years), understanding its underlying causes is critical.  

“HFpEF is a complex syndrome, involving abnormalities in many different organs”, says lead investigator David Kass, MD, Professor of Medicine at the Johns Hopkins University School of Medicine. “We call it heart failure (HF) because its symptoms are similar to those found in patients with hearts that are weak. However, with HFpEF, heart contraction seems fine, yet heart failure symptoms still exist. While many prior efforts to treat HFpEF using standard HF drugs have not worked, success has since come from drugs used to treat diabetes and obesity.”

More specifically, the drug used to treat diabetes, known as an SGLT2 inhibitor (sodium glucose transporter 2 inhibitor) is currently the only evidence-based drug for HFpEF that has improved not only its symptoms but also reduced long-term rehospitalisation rates and endpoints of mortality. The weight loss drug GLP1-receptor agonist has been tested and found to improve symptoms in patients with HFpEF, and ongoing studies are determining if a similar hard end-point (mortality reduction, hospitalisation for HF reduction) are also possible outcomes. As such, these drugs have already been shown to be effective not only in diabetes where they started, but also in HFpEF.

To perform the study, the research team obtained a small piece of muscle tissue from 25 patients who had been diagnosed with varying degrees of HFpEF caused by diabetes and obesity and compared them to heart tissue from 14 organ donors whose hearts were considered to be normal. They examined the muscle using an electron microscope that shows muscle structure at a very high magnification.  

Mariam Meddeb, MD, MS, cardiovascular disease specialist at the Johns Hopkins University School of Medicine, who conducted the study says that a scanning electron micrograph “provides a very clear picture inside the muscle cell, what we call ultrastructure, such as mitochondria that are the energy power plants, and sarcomeres (unit of muscle fibre) that generate force”.

The researchers found notable ultrastructural abnormalities were particularly present in tissue of the most obese patients who had HEpEF, which had mitochondria that were swollen, pale, and disrupted, had many fat droplets, and their sarcomeres appeared tattered. These abnormalities were not related to whether the patient had diabetes, and were less prominent in patients who were less obese.

“These results will help those trying to develop animal models of HFpEF, since they show what one wants to generate at this microscopic level,” notes Dr Kass. “It also raises the key question of whether reducing obesity, as is now being done with several drug therapies, will reverse these ultrastructural abnormalities, and in turn improve HFpEF outcome.”  

Source: John Hopkins Medicine

Categories : Cardiovascular DiseaseTags :

Is it Time to Stop Recommending Strict Salt Restriction in Heart Failure?

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Credit: Pixabay CC0

For decades, it’s been thought that people with heart failure should drastically reduce their dietary salt intake, but some studies have suggested that salt restriction could be harmful for these patients. A recent review in the European Journal of Clinical Investigation that assessed all relevant studies published between 2000 and 2023 has concluded that there is no proven clinical benefit to this strategy for patients with heart failure.

Most relevant randomised trials were small, and a single large, randomised clinical trial was stopped early due to futility. Although moderate to strict salt restriction was linked with better quality of life and functional status, it did not affect mortality and hospitalisation rates among patients with heart failure.

“Doctors often resist making changes to age-old tenets that have no true scientific basis; however, when new good evidence surfaces, we should make an effort to embrace it,” said author Paolo Raggi MD, PhD, of the University of Alberta.

Source: Wiley

Categories : Cardiovascular Disease GastrointestinalTags :

Inflammatory Bowel Disease may Increase Risk of Heart Failure

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Irritable bowel syndrome. Credit: Scientific Animations CC4.0

Inflammatory bowel disease (IBD) is associated with a slightly increased risk of heart failure up to 20 years after diagnosis, according to a comprehensive registry study from Karolinska Institutet published in the European Heart Journal.

The researchers analysed the risk of heart failure in over 80 000 patients with inflammatory bowel disease, that is, Crohn’s disease, ulcerative colitis or unclassified IBD, compared with 400 000 people from the general population, as part of the ESPRESSO study.

The results show that people with IBD have a 19% increased risk of developing heart failure up to 20 years after diagnosis. This corresponds to one extra heart failure case per 130 IBD patients in those 20 years, and the risk increase was seen regardless of the type of IBD. The highest risk of heart failure was seen in older patients, people with lower education and people with pre-existing cardiovascular-related disease at IBD diagnosis.

Contribute to new guidelines

“Both healthcare providers and patients should be aware of this increased risk, and it’s important that cardiovascular health is properly monitored,” says the study’s first author Jiangwei Sun, researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet. “We hope the results will raise the awareness of health workers as to the increased risk of heart failure in individuals with IBD and contribute to new guidelines for cardiovascular disease management in IBD patients.”

Comparing siblings with and without ABD, the risk increase was slightly lower, 10%, suggesting that genetics and early environmental factors shared within families may play a role. 

“We don’t know if there is a causal relationship, but we will continue to explore genetic factors and the role of IBD medications and disease activities on the risk of heart failure,” says the study’s senior author Professor Jonas F. Ludvigsson from the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet.

Source: Karolinska Institutet

Categories : Cardiovascular DiseaseTags :

New Advance against Heart Failure Caused by Y Chromosome Loss

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Chromosomes. Credit: NIH

Researchers have discovered a gene on the Y chromosome that contributes to the greater incidence of heart failure in men when the Y chromosome is lost to ageing.

Y chromosome loss in men occurs progressively throughout life and can be detected in approximately 40% of 70-year-old men. In 2022, Kenneth Walsh, PhD, at University of Virginia discovered that this loss can contribute to heart muscle scarring and lead to heart failure. (That finding was the first to directly link Y chromosome loss to a specific harm to men’s health; Y chromosome loss is increasingly thought to play a role in diseases ranging from Alzheimer’s to cancer.)

In an important follow-up finding published in Nature Cardiovascular Research, Walsh and his team have discovered how Y chromosome loss triggers changes in heart immune cells that make the cells more likely to cause scarring and heart failure.

Further, the researchers found they could reverse the harmful heart changes by giving lab mice a drug that targets the process of fibrosis that leads to the heart scarring, which could lead to a similar treatment for men.

“Our previous work identified that it was loss of the entire Y chromosome that contributed to heart disease in men,” said Walsh, the director of UVA’s Hematovascular Biology Center. “This new work identified a single gene on the Y chromosome that can account for the disease-promoting effects of Y chromosome loss.”

About Y chromosome loss

Unlike women, who have two X chromosomes, men have an X and a Y. For a long time, the genes found on the Y chromosome were not thought to play important roles in disease. Sex hormones, scientists thought, explained the differences in certain diseases in men and women. But Walsh’s groundbreaking work has helped change that perception. It also suggested an explanation for why heart failure is more common in men than women. (Cardiovascular disease, which includes heart failure, is the leading cause of death worldwide.)

Y chromosome loss occurs in only a small percentage of affected men’s cells. This results in what is called “mosaicism,” where genetically different cells occur within one individual. Researchers aren’t entirely sure why this partial Y chromosome loss occurs, but predominantly it strikes elderly men and men who smoke compared to those who don’t.

To better understand the effects of Y chromosome loss, Walsh and his team examined genes found on the Y chromosome to determine which might be important to heart scarring. One gene they looked at, Uty, helps control the operating instructions for immune cells called macrophages and monocytes, the scientists determined. When the Uty gene was disrupted, either individually or through Y chromosome loss, that triggered changes in the immune cells in lab mice. Suddenly, the macrophages were much more “pro-fibrotic,” or prone to scarring. This accelerated heart failure as well, the scientists found.

“The identification of a single gene on the Y chromosome provides information about a new druggable target to treat fibrotic diseases,” said Walsh, of UVA’s Division of Cardiovascular Medicine and Robert M. Berne Cardiovascular Research Center.

Walsh and his team were able to prevent the harmful changes in the mice’s macrophages by giving them a specially designed monoclonal antibody. This halted the harmful changes in the heart, suggesting the approach might, with further research, lead to a way to treat or avoid heart failure and other fibrotic diseases in men with Y chromosome loss.

“Currently, we are working with our clinician colleagues in the Division of Cardiovascular Medicine at UVA to assess whether loss of the Y chromosome in men is associated with greater scarring in the heart,” Walsh said. “This research will provide new avenues for understanding the causes of heart disease.”

Based on their findings, Walsh and his team believe that a small group of genes found on the Y chromosome may have big effects on a wide array of diseases. Their new work identifies mechanisms that may lead to this, and they are hopeful that further research will provide a much better understanding of unknown causes of sickness and death in men.

“This research further documents the utility of studying the genetics of mutations that are acquired after conception and accumulate throughout life,” Walsh said. “These mutations appear to be as important to health and lifespan as the mutations that are inherited from one’s parents. The study of these age-acquired mutations represents a new field of human genetics.”

Source: University of Virginia Health System