The Heart: Heart disease and stroke news and discussions

weatheriscool
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New miniature heart could help speed heart disease cures

by Andrew Thurston, Boston University
There's no safe way to get a close-up view of the human heart as it goes about its work: you can't just pop it out, take a look, then slot it back in. Scientists have tried different ways to get around this fundamental problem: they've hooked up cadaver hearts to machines to make them pump again, attached lab-grown heart tissues to springs to watch them expand and contract. Each approach has its flaws: reanimated hearts can only beat for a few hours; springs can't replicate the forces at work on the real muscle. But getting a better understanding of this vital organ is urgent: in America, someone dies of heart disease every 36 seconds, according to the Centers for Disease Control and Prevention.

Now, an interdisciplinary team of engineers, biologists, and geneticists has developed a new way of studying the heart: they've built a miniature replica of a heart chamber from a combination of nanoengineered parts and human heart tissue. There are no springs or external power sources—like the real thing, it just beats by itself, driven by the live heart tissue grown from stem cells. The device could give researchers a more accurate view of how the organ works, allowing them to track how the heart grows in the embryo, study the impact of disease, and test the potential effectiveness and side effects of new treatments—all at zero risk to patients and without leaving a lab.
https://medicalxpress.com/news/2022-04- ... sease.html
weatheriscool
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Researchers observe three types of hormone response to surgical disruption in cardiac patients
https://medicalxpress.com/news/2022-04- ... rdiac.html
by University of Bristol
Cardiac surgery patients may experience different levels of disruption to their body producing life-saving hormones during their operations, a new study reveals.

Major surgery and critical illness produce a potentially life-threatening systemic inflammatory response, which is counterbalanced by changes in adrenocorticotrophic hormone (ACTH) and cortisol.

The body's stress response system, known as the hypothalamic-pituitary-adrenal (HPA) axis, controls the production of these hormones as a vital part of patients' response to surgery, but researchers have found that there is no simple graded HPA response to cardiac surgery.

Research by experts at the Universities of Birmingham and Bristol, published today in Journal of The Royal Society Interface, shows cardiac surgery causes major dynamic changes in concentration of ACTH and cortisol, as well as their pattern of secretion.

Using novel mathematical techniques, researchers developed a model of HPA axis activity that predicts the physiological mechanisms responsible for different patterns of cortisol secretion.
weatheriscool
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Targeting molecular pathway that causes pulmonary arterial hypertension
https://medicalxpress.com/news/2022-05- ... nsion.html
by Scott Lafee, University of California - San Diego

Pulmonary arterial hypertension (PAH) is a type of high blood pressure in the lungs, in which blood vessels are narrowed, blocked or destroyed, causing the heart to work harder and, in time, result in cardiac weakness and failure.

The disease is relatively rare, but affects an estimated 100,000 persons in the United States, and results in 20,000 deaths annually. There is no cure.

In a study published May 4, 2022 in Science Translational Medicine, researchers at the University of California San Diego School of Medicine describe the underlying signaling pathway that results in PAH—and a novel monoclonal antibody therapy that blocks the abnormal blood vessel formation characterizing the disease.

At the cellular level, PAH progresses with proliferation of vascular smooth muscle cells (vSMC) that cause small arteries in the lungs to become narrowed, leading to progressively less oxygen in the blood. A research team, led by senior author Patricia A. Thistlethwaite, MD, Ph.D., professor of surgery in at UC San Diego School of Medicine and a cardiothoracic surgeon at UC San Diego Health, focused on overexpression of the NOTCH ligand JAGGED-1, a binding protein involved in cell signaling and, in this case, the development of small pulmonary vSMCs.
weatheriscool
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Researchers develop wireless implantable vascular monitoring system
https://medicalxpress.com/news/2022-05- ... cular.html
by Georgia Institute of Technology
Vascular diseases are public enemy number one: the leading killers worldwide, accounting for nearly a third of all human deaths on the planet.

Continuous monitoring of hemodynamics—blood flow through the vascular system—can improve treatments and patient outcomes. But deadly conditions like hypertension and atherosclerosis occur in long and twisting vascular system with arteries of varying diameter and curvature, and existing clinical devices are limited by their bulk, rigidity, and utility.

Georgia Institute of Technology researcher Woon-Hong Yeo and his collaborators are trying to improve the odds for patients with development of an implantable soft electronic monitoring system. Their new device, consisting of a smart stent and printed soft sensors, is capable of wireless real-time monitoring of hemodynamics without batteries or circuits.

"This electronic system is designed to wirelessly deliver hemodynamic data, including arterial pressure, pulse, and flow, to an external data acquisition system, and it is super small and thin, which is why we can use a catheter to deliver it, anywhere inside the body," said Yeo, whose team released its study this week in the journal Science Advances.
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Haywire T cells attack protein in "bad" cholesterol
https://medicalxpress.com/news/2022-05- ... terol.html
by La Jolla Institute for Immunology

Preventing atherosclerosis, the underlying cause of heart disease, means scientists need to understand how immune cells drive inflammation in the arteries.

The challenge is that the T cells involved in atherosclerosis are very rare and extremely hard to find in the bloodstream. "This is a classic needle-in-the-haystack problem," says La Jolla Institute for Immunology (LJI) Professor Klaus Ley, M.D.

But T cells can't hide forever. In a study published recently in Nature Cardiovascular Research, Ley and his colleagues describe a group of T cells that attack a protein called apolipoprotein B (APOB).

APOB is the main protein component of LDL, or "bad," cholesterol. Dangerous plaques can form in the arteries as LDL levels increase in the bloodstream. These plaques can drive inflammation, block blood flow, and even break apart to trigger strokes and heart attacks.
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Diagnostic procedure to speed personalized treatment of acute stroke
https://medicalxpress.com/news/2022-06- ... acute.html
by Swiss Federal Laboratories for Materials Science and Technology
A blood clot in the brain that blocks the supply of oxygen can cause an acute stroke. In this case, every minute counts. A team from Empa, the University Hospital in Geneva and the Hirslanden Clinic is currently developing a diagnostic procedure that can be used to start a tailored therapy in a timely manner, as they write in the current issue of the journal Scientific Reports.

There is no warning sign: From one moment to the next, entire brain areas are blocked. When a clot occludes a blood vessel, the oxygen supply to the brain is interrupted, and the affected person suffers an acute cerebral stroke. The life-threatening condition can manifest itself in many different ways: from muscle paralysis to loss of hearing or vision to unconsciousness. But one thing is certain: This is a medical emergency, and the time span until the vascular blockage is resolved must be as short as possible in order to save as many nerve cells as possible from dying. This is the only way to prevent permanent neurological damage.

Which treatment is best suited for this purpose is not always easy to determine in the required rush. Based on X-ray analysis and electron microscopy, a team from Empa, the Hirslanden Clinic and the University Hospital in Geneva is currently developing a method that should enable the optimal therapy to be identified in the shortest possible time. A first study has been published in the scientific journal Scientific Reports. This data should provide the basis for tailored treatment in the sense of personalized medicine.
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New understanding of congenital heart disease progression opens door to improved treatment options
https://medicalxpress.com/news/2022-06- ... tment.html
by Graciela Gutierrez, Baylor College of Medicine

A team of investigators from Baylor College of Medicine, Texas Heart Institute and Texas Children's Hospital uncovered new insights into the mechanisms underlying the progression of congenital heart disease (CHD)―a spectrum of heart defects that develop before birth and remain the leading cause of childhood death.

The research published in Nature represents the first reported single-cell genomics evidence of unique differences in heart muscle cells and immune systems of CHD patients. Uncovering these key differences and how these diseases progress provides an opening for researchers to devise new ways to treat CHD.

While the eventual outcome of heart failure in CHD is well documented, the underlying cause of declining heart function in these patients is still poorly understood. That knowledge gap in understanding has led to roadblocks in developing new therapies capable of extending a patient's life.
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caltrek
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A Major Step Forward for Organ Biofabrication
July 8, 2022

Introduction:
(EurekAlert) Heart disease — the leading cause of death in the U.S. — is so deadly in part because the heart, unlike other organs, cannot repair itself after injury. That is why tissue engineering, ultimately including the wholesale fabrication of an entire human heart for transplant, is so important for the future of cardiac medicine.

To build a human heart from the ground up, researchers need to replicate the unique structures that make up the heart. This includes recreating helical geometries, which create a twisting motion as the heart beats. It’s been long theorized that this twisting motion is critical for pumping blood at high volumes, but proving that has been difficult, in part because creating hearts with different geometries and alignments has been challenging.

Now, bioengineers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed the first biohybrid model of human ventricles with helically aligned beating cardiac cells, and have shown that muscle alignment does, in fact, dramatically increases how much blood the ventricle can pump with each contraction.
Read more here: https://www.eurekalert.org/news-releases/958323

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weatheriscool
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Creating an 'adult-like' mature human cardiac tissue

by Courtney Chandler, University of Connecticut
https://medicalxpress.com/news/2022-07- ... issue.html
Researchers in the Biomedical Engineering Department at UConn have developed a new cardiac cell-derived platform that closely mimics the human heart, unlocking potential for more thorough preclinical drug development and testing, and model for cardiac diseases.

The research, published in Cell Reports by Assistant Professor Kshitiz in collaboration with Dr. Junaid Afzal in the cardiology department at the University of California San Francisco, presents a method that accelerates maturation of human cardiac cells towards a state suitable enough to be a surrogate for preclinical drug testing.

"There is a very strong need to create human cardiac constructs for all sorts of applications. Small animal models just do not recapitulate human heart biology, and human samples are scarce," says Kshitiz. "This matters because all drugs need to be tested for their toxicity to heart. It is widely believed that a large number of them unnecessarily fail clinical trials because we do not have human samples to test them with."

Kshitiz and Afzal first identified the need to create a matured human cardiac tissue during their time together at Johns Hopkins Medicine.

"When methods were developed to differentiate human pluripotent stem cells to cardiac cells, it created a big hope that finally we will have human heart constructs to work with," said Afzal. "While it is straightforward to get human cardiac cells, they are similar to fetal cells. What we need is adult cells."
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Fast-acting immune cells provide powerful protection against stroke
https://medicalxpress.com/news/2022-08- ... erful.html
by University of Pittsburgh
A unique subset of white blood cells confers fast-acting and lasting protection against ischemic stroke in mice, University of Pittsburgh neurologists and immunologists reported in the Journal of Clinical Investigation today.

This study identified a novel subset of CD8+ regulatory-like T cells, or CD8+TRLs, as "first responders" to stroke. Attracted to the site of ischemic injury by a unique "homing" signal released by dying brain cells, CD8+TRLs reach the brain within 24 hours after stroke onset, where they release molecules that provide direct neuroprotective effects, as well as limit inflammation and secondary brain damage.

"The beauty of CD8+TRLs is in their fast response. They confer very potent protection to the brain, which can last a long time," said co-corresponding author Xiaoming Hu, M.D., Ph.D., associate professor of neurology at Pitt and a U.S. Department of Veterans Affairs (VA) investigator. "Most importantly, these cells are easily accessible because they circulate in the blood before they enter the injured brain."

"Creating shelf-stable and ready-to-use CD8+TRLs or developing a cocktail of neuroprotective signaling molecules released by those cells once they reach the brain could present effective future therapies against stroke and offer hope to hundreds of thousands of patients who are ineligible for treatments available to them currently," said co-senior author Jun Chen, M.D., Ph.D., professor of neurology at Pitt and a U.S. Department of VA investigator.
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