USF Health microbiome expert Hariom Yadav, PhD, has received a grant from the National Institute on Aging to help determine if a common medication can restore microbiome diversity in older patients who have a form of heart failure and, thus, prevent the subsequent problems that tend keep these patients inactive and cause their conditions to worsen.

Hariom Yadav, PhD, was recently recruited to lead the USF Microbiome Research Center and his research focuses on the gut-brain connection (gut-brain axis) in relation to cognitive function.

Dr. Yadav, associate professor in the Division of Digestive Diseases and Nutrition for the Department of Neurosurgery and Brain Repair and Internal Medicine in the USF Health Morsani College of Medicine and director of the USF Center for Microbiome Research in the Microbiomes Institute, is a co-principal investigator and is working with co-principal investigator and project lead Dalane Kitzman, MD, at Wake Forest University in Winston-Salem, North Carolina.

The 3-year NIH consortium project research, which will include patients diagnosed with heart failure with preserved ejection fraction (HFpEF), is titled “Repurposing of Metformin for Older Patients with HFpEF.”

Preclinical studies show that gut barriers, including mucin production, are reduced in older gut and cause ‘leaky gut’, which allows certain antigens to diffuse into blood circulation, thus causing systemic inflammation. Preliminary data also suggest that older HFpEF patients have markedly reduced microbiome diversity, including reduced production of beneficial metabolites such as butyrate, which maintain health and gut wall integrity, and may help reduce leaky gut.

Metformin prescription bottle. Metformin is a generic medication name and label was created by photographer.

Metformin is a generic FDA-approved medication used for diabetes. Earlier studies, including research in Dr. Yadav’s lab, shows that metformin decreases leaky gut by improving microbial diversity and increasing intestinal wall mucin production thereby reducing systemic inflammation and improving physical function in lab model studies.

This new study seeks to translate these findings to determine if metformin improves microbiome diversity, reduces leaky gut, and reduces the inflammation associated with HFpEF in patients, a common condition in older people, particular older women.

“Earlier research suggests that metformin can inhibit a root cause of systemic inflammation – leaky gut – and its adverse consequences which are highly relevant to HFpEF, including exercise intolerance, a known barrier for HFpEF patients for staying active,” Dr. Yadav said. “We propose to test repurposing of metformin, a promising medication for improving heart failure outcomes by improving gut leakiness and microbial diversity, and that metformin will restore gut microbiome diversity and increase gut wall mucin, which in turn will reduce leaky gut and systemic inflammation and improve physical function for HFpEF patients.”

This new study is a randomized, blinded, placebo-controlled trial over 20 weeks in 80 non-diabetic HFpEF patients age 60 and older. The Wake Forest and Atrium Health team will coordinate the patients, measuring physical function, provide a quality of life questionnaire, and collect stool and blood samples. The team in Dr. Yadav’s lab will examine the samples and measure microbiome diversity and the key markers of leaky gut and of inflammation.

This study is supported by the National Institute on Aging of the National Institutes of Health under Award Number U01AG076928.

Dr. Yadav is conducting similar research associated with leaky gut and inflammation, including their connections to Alzheimer’s disease and other related dementias.

USF Health-led research validates crucial role of the spleen in cardiac healing, suggests targeting lipid mediator S1P may offer a promising heart failure treatment

Tampa, FL (Aug. 23, 2021) — Although we can survive without a spleen, evidence continues to mount that this abdominal organ plays a more valuable role in our physiological defenses than previously suspected.

“The spleen holds a whole army of immune cells and signaling molecules that can be rapidly mobilized to respond whenever a major injury like a heart attack or viral invasion occurs,” said Ganesh Halade, PhD, an associate professor of cardiovascular sciences at the University of South Florida Health (USF Health) Morsani College of Medicine.

Principal investigator Ganesh Halade, PhD, is an associate professor of cardiovascular sciences at the USF Health Morsani College of Medicine and a member of the college’s Heart Institute. | Photo by Allison Long, USF Health Communications

Dr. Halade led a new preclinical study that analyzed the interactions of the lipid mediator sphingosine-1-phosphate (S1P) in the spleen and heart during the transition from acute to chronic heart failure. The researchers discovered new cardiac repair mechanisms to help shed light on spleen-heart coordination of physiological inflammation in a mouse model of heart failure.

The study appeared online August 20 in the American Journal of Physiology- Heart and Circulation.

“Simply put, we showed that the spleen and the heart work together through S1P for cardiac repair,” said principal investigator Dr. Halade, a member of the USF Health Heart Institute. “Our study also suggests that early detection of little or no S1P levels after a heart attack and targeted activation of this bioactive lipid mediator may provide a cardioprotective treatment for patients at high risk of heart failure.”

Dr. Halade and colleagues have defined connections between fatty acids, dysfunctional inflammation control, and heart failure. His laboratory focuses on discovering ways to prevent, delay or treat unresolved inflammation after a heart attack. In this latest study, the researchers turned their attention to where S1P is produced and its role in cardiac repair.

S1P is a lipid mediator dysregulated during inflammatory responses, including heart failure. Moreover, several groups have demonstrated the potential significance of this signaling molecule as a treatment target for heart failure triggered by heart attack and ischemia-reperfusion injury.

People can survive without a spleen, a fist-sized abdominal organ that helps fight infection. But its removal (due to abdominal trauma, or certain medical conditions) has been linked to an increased risk of death from ischemic heart disease.

The USF Health study captured time-dependent movement of S1P from the spleen through circulating blood plasma to the heart. The work was the first to quantify interactions between S1P and S1P receptor 1 (S1PR1) during the progression from acute to chronic heart failure, Dr. Halade said.

The researchers defined S1P/S1PR1 signaling in both mice and humans with heart failure after a heart attack. The otherwise young, healthy “risk-free” mice had no variable cardiovascular risk factors such as obesity, diabetes, hypertension, and aging commonly seen in a clinical setting. The researchers correlated the physiological data from the cardiac-repair mouse model experiments with what they observed in pathologically failing human hearts.

Among their key findings:

• Cardiac-specific S1P and S1PR1 levels were reduced in patients with ischemic heart failure.
• In the risk-free mice, physiological cardiac repair was facilitated by activation of S1P in the heart and the spleen. S1P/S1PR1 signaling increased in both organs from acute through chronic heart failure, helping to promote cardiac repair after heart attack.
• Increased plasma S1P indicates cardiac repair in the acute phase of heart failure.
• Selective activation of the S1P receptor in macrophages (immune cells that that help clear inflammation and guide tissue repair) suppressed biomarkers of inflammation and accelerated biomarkers of cardiac healing in mouse cells.

“This study provides another example that the spleen should not be underestimated, because it contributes to the foundation of our immune health as well as the root cause of inflammatory diseases, including cardiovascular disease,” Dr. Halade said.

The research was supported by grants from the National Institutes of Health and the U.S. Department of Veterans Affairs.  The University of South Florida team worked with collaborators at the University of Alabama at Birmingham and Hokkaido University, Japan.

USF Health preclinical study finds that inhibiting lipoxygenase with a drug alters
innate inflammatory response, delaying heart tissue repair after cardiac injury

TAMPA, Fla. (May 10, 2021) — Blocking the fat-busting enzyme lipoxygenase with a synthetic inhibitor throws the immune system’s innate inflammatory response out of whack, compromising cardiac repair during acute heart failure, USF Health researchers found.

Their new preclinical study was published April 13 in Biomedicine & Pharmacotherapy.

In search of individualized heart failure therapies, Ganesh Halade, PhD, leads a USF Health Heart Institute team studying unresolved inflammation after heart attack. | Photo by Allison Long, USF Health Communications

Acute heart failure – triggered by a heart attack, severely irregular heartbeats, or other causes — occurs suddenly when the heart cannot pump enough blood to meet the body’s demands.

Following a heart attack or any cardiac injury, signals to immune cells called leukocytes carefully control physiological inflammation. Normally, there are two distinct but overlapping processes: an acute inflammatory response (“get in” signal), where leukocytes travel from the spleen to the injured heart to start removing dead or diseased cardiac tissue, and a resolving phase (“get out” signal), where inflammation is cleared with the help of macrophages that arrive to further repair the damage and form a stable scar.

A delay in either the initiation of inflammation or its timely clearance (resolution) can lead to impaired cardiac healing and progression to heart failure, said study principal investigator Ganesh Halade, PhD, an associate professor of cardiovascular sciences at the USF Health Morsani College of Medicine and a member of the USF Health Heart Institute.

The USF Health researchers applied three investigational approaches (in vitro, ex vivo, and in vivo) to assess whether a potent lipoxygenase (12/15 LOX) inhibitor ML351 could selectively alter inflammatory responses in adult mice following cardiac injury similar to a heart attack. Previous studies by Dr. Halade’s laboratory reported that lipoxygenase-deficient mice showed improved cardiac repair and heart failure survival after cardiac injury.

“We wondered if blocking a lipoxygenase with an external pharmacological compound (drug) would have the same beneficial effect — but the answer was no,” Dr. Halade said. “Instead, the collective results of our study indicate that ML351 dysregulated control of the normal physiological pathway of inflammation in cardiac repair, causing collateral damage.”

In the mice treated mice with ML351, leukocyte recruitment to the site of cardiac injury was delayed, which subsequently amplified inflammation at the site. At the same time, instead of leaving once the repair job was done, the immune cells remained at the site beyond the typical acute (and beneficial) inflammatory response phase. Basically, the late arrival (get-in signal) and delayed clearance (get-out signal) of immune cells impaired cardiac repair, Dr. Halade said.

A delay in either the initiation of inflammation or its timely clearance (resolution) can lead to impaired cardiac healing and progression to heart failure.

The latest study helps explain one more piece of the puzzle about the important role of immune-mediated acute inflammation and its clearance – both in promoting cardiac health and stopping the progression of heart failure, Dr. Halade said. Lipoxygenases, fatty-acid modifying enzymes that control metabolic and immune signaling, can promote either resolving (beneficial) or nonresolving (harmful) inflammation, he added.

“The take-home message is do not mess with (block) the lipoxygenase. Preserve it, because it’s a key enzyme for our defensive, innate immune response,” he said. “Knowing how drugs interact with the body’s precisely-balanced immune responses will be critical for understanding mechanisms to prevent, delay or treat the unresolved inflammation influencing heart failure.”

The USF Health study was supported by grants from the NIH’s National Heart, Lung and Blood Institute and the National Institute of Diabetes and Digestive and Kidney Diseases.

In search of individualized heart failure therapies, Ganesh Halade leads a USF Health Heart Institute team studying unresolved inflammation after heart attack

//www.youtube.com/watch?v=KarBPXZs1rs

Short-term inflammation is one of the body’s key defense mechanisms to help repair injury and fight infection. But low-level inflammation that does not subside has been linked to many common chronic conditions, including cardiovascular diseases such as atherosclerosis, atrial fibrillation and heart failure.

Ganesh Halade, PhD, an associate professor of cardiovascular sciences at the USF Health Morsani College of Medicine, investigates the safe clearance of acute inflammation – and what happens at the molecular and cellular levels when initially beneficial inflammation becomes harmful to the heart.  His team at the USF Health Heart Institute works on bridging the gap between the immune-responsive metabolism of fat and cardiac health by more clearly defining two distinct but simultaneous processes: the inflammatory response and how inflammation is safely cleared, or resolved.

In particular, Dr. Halade’s laboratory focuses on discovering ways to prevent, delay or treat the unresolved inflammation after a heart attack, which plays a key role in the pathology leading to heart failure. Their goal is to contribute to individualized therapies that may account for possible sex, racial/ethnic or age-related physiological differences in heart failure, a leading cause of hospitalizations and deaths worldwide.

Ganesh Halade, PhD, associate professor of cardiovascular sciences, joined the USF Health Heart Institute in February 2020. [Photo by Allison Long, USF Health Communications]

“Although several treatments and devices exist to help manage heart failure, the challenge remains the growth of metabolic risk factors like obesity, diabetes, hypertension and aging that amplify heart failure – and inflammation underlies all these conditions,” Dr. Halade said. “We’re in the early stages of understanding how the inflammatory response becomes chronic, or unresolved” after heart attack-induced injury.

Honing in on “the roots”

Dr. Halade’s late father, a farmer in Nashik close to Mumbai, India, emphasized to his young son that if he wanted to make a difference in life to “look to the roots, rather than the fruits.”

That philosophy drives Dr. Halade’s research endeavors. “We focus on the root causes of inflammation so that we can successfully treat the chronic inflammation that leads to heart failure,” he said.

Dr. Halade (center) with his research team, postdoctoral fellow Bochra Tourki, PhD, (left) and research associate Vasundhara Kain, PhD, (right). [Allison Long, USF Health Communications]

Clinical trials of several anti-inflammatory therapies so far have failed to show benefit in heart failure patients. Dr. Halade suggests that the investigational compounds intended to suppress inflammation very early in the cardiovascular disease process likely disrupt the tight control of immune-responsive signaling needed for timely resolution of inflammation.

“The inflammatory response and its resolution are two sides of the same coin – and they roll together. Blocking one side will affect the other,” he explained. “So, we don’t want to block the ‘get in signal’ needed to promote the early, ‘good’ inflammation. We want to accelerate the ‘get out’ signal to immune cells, so that as soon as repair of cardiac injury is done the acute inflammation leaves without becoming chronic.”

Dr. Halade views a high-resolution image (below) of a normally beating heart. [Photos by Anne DeLotto Baier, USFH Research Communications]

Connecting dysfunctional inflammation control and heart failure

A class of immune-system molecules orchestrates the resolution of tissue inflammation, an active process essential for advancing cardiac healing after a heart attack. These specialized proresolving mediators, or SPMs, are signaling molecules that form when fatty acids metabolize in response to immune activation of leukocytes.

Dr. Halade’s work is helping uncover new details on how heart failure-inducing inflammation may be limited (without promoting immunosuppression) – either by administering pharmacological SPMs, or activating enzymes that help stimulate the body’s own SPMs.

Over the last two years, he has published significant findings in several leading journals (papers summarized below) making the connections between fatty acids, inflammation control, and heart failure. Among Dr. Halade’s study collaborators is Charles Serhan, PhD, of Harvard Medical School, a pioneer in the emerging field of inflammation resolution.

• Science Signaling: This study followed the time course of inflammation and its resolution in a mouse heart attack model. The research showed for the first time that the active inflammation-resolving phase coincided with the acute inflammatory response facilitating cardiac repair after a heart attack. Among other factors, the researchers looked at types and amounts of SPMs, and the expression of enzymes that synthesize SPMs, both in the spleen and at the injured site of the heart. Macrophages, a type of white blood cell, are needed to generate SPMs as opposed to other immune cells, they reported.

Dr. Halade’s laboratory focuses on discovering ways to prevent, delay or treat the unresolved inflammation after a heart attack, which plays a key role in the pathology leading to heart failure. [Anne DeLotto Baier]

• Journal of the American Heart Association: The preclinical study discovered male-female cardiac repair differences in heart failure survival after heart attack, including improved recovery of cardiac function and greater survival of acute and chronic heart failure in female mice. Females generated higher levels of a particular fatty acid-derived signaling molecule (EET; epoxyeicosatrienoic acids) known to facilitate healing after a heart attack.

• ESC Heart Failure: The researchers profiled bioactive lipids (inflammatory biomarkers) in blood samples from hospitalized Black and White patients soon after a severe heart attack. They found a potent SPM signature (resolvin E1) was significantly lower in Black men and women than in Whites. The study concluded bioactive lipids are key for the diagnosis and treatment of cardiac repair after heart attack to delay heart failure.

• The FASEB Journal: Halade and colleagues identified a mouse model to study heart failure with preserved ejection fraction (HFpeF), a common form of heart failure linked to age-related obesity. Using this unique model of obese aging, they defined how the deficiency of a single resolution receptor triggers obesity in mice at an early age, which can give rise to many of the molecular and cellular processes ultimately leading to HFpEF.

Vasundhara Kain (seated) and Bochra Tourki, look at slides for a paper on age-related obesity and heart failure. [Allison Long, USF Health Communications]

Insight into potential inflammation-resolving therapies

As they learn more about the metabolic and immune-responsive signals that control acute cardiac inflammation, researchers hope to harness the capacity of fatty acid-derived bioactive molecules to prevent, diagnose and treat heart failure, Dr. Halade said. SPMs are derived primarily from omega-3 fats in our diet – the polyunsaturated “good” fats in foods like salmon, avocados, almonds, and walnuts.

Some evidence indicates that omega 3-rich diets and/or SPM supplements, as well as getting enough exercise and quality sleep may help prevent the unresolved inflammation leading to heart failure, Dr. Halade said. If SPMs are not produced due to risk factors like obesity or aging, or because enzymes required to metabolize fatty acids are deficient, then drugs specifically designed to facilitate cardiac repair and calm inflammation might delay or treat heart failure, he added. Distinctive biochemical signatures acquired by analyzing SPMs or other metabolites might even be used to help diagnose heart failure or predict which treatments will work best for certain patients.

Dr. Halade joined USF Health this February from the University of Alabama at Birmingham, where he was a faculty member since 2013. He received his PhD in pharmacology from the University of Mumbai Institute of Chemical Technology in 2007. He completed two postdoctoral fellowships at the University of Texas Health Science Center in San Antonio. The first fellowship focused on nutritional immunology. The second was conducted with mentor Merry Lindsey, PhD, to examine the effects of obesity on post-heart attack cardiac structure and function.

Foods rich in omega-3 fatty acids (including salmon, walnuts and avocados), as well as enough exercise and quality sleep, may help prevent unresolved inflammation contributing to cardiovascular disease.

Dr. Halade’s research is supported by funding from the NIH’s National Heart, Lung and Blood Institute. In 2018, he received American Physiological Society Research Career Enhancement Award to train in lipidomics at the RIKEN Center for Integrative Medical Sciences in Japan.

His inflammation resolution research has been recognized with two awards for studies published in the American Journal of Physiology-Heart and Circulatory. An Article Impact Award 2020 was conferred this March by the American Physiological Society for Dr. Halade’s work defining the impact of the cancer drug doxorubicin on the heart and spleen. He also received a 2017 Best Paper Award from the Unbound Science Foundation. Dr. Halade is associate editor for the American Journal of Physiology-Heart and Circulatory and for Scientific Reports, and serves on the editorial boards of several other high-impact journals in cardiovascular sciences.

At left: Beneficial resolution of inflammation following cardiac repair. At right: Risk factors like aging, obesity and some medications can contribute to unresolved (chronic) inflammation, which impairs cardiac repair and can lead to heart failure. [Graphic courtesy of Ganesh Halade]

Some things you may not know about Dr. Halade

• As an undergraduate student in India, Dr. Halade won the gold medal in fencing at a statewide collegiate competition.
• To help promote a heart healthy lifestyle, he enjoys recreational bicycling and gardening in his backyard, where he grows vegetables and chiles.
• Halade lives in Tampa with his wife Dipti, an information technology engineer, and their son Arav, 13.

Top:  Sources of inflammation include injury (like damage from a heart attack), infection (viruses, bacteria or other pathogens), and factors associated with lifestyle (such as poor diet and lack of exercise). Below: Ways to help prevent unresolved cardiac inflammation associated with lifestyle. [Graphics courtesy of Ganesh Halade]

-Video by Allison Long, USF Health Communications and Marketing

USF Health-UAB study indicates that lipid mediators may offer new targets for more personalized heart failure diagnosis and treatment

The new study profiled bioactive lipids in blood samples collected from hospitalized black and white patients soon after a severe heart attack.

TAMPA, Fla (May 4, 2020) — Black men and women have higher incidences than whites of developing advanced heart failure following a heart attack. Despite racial disparities in heart attacks (a leading contributor to heart failure), and rehospitalizations and deaths caused by heart disease, the underlying physiology accounting for worse cardiovascular outcomes among blacks is poorly understood.

A new study published May 4 in ESC Heart Failure profiles bioactive lipids in blood samples from hospitalized black and white patients soon after a severe heart attack. The preliminary research was conducted by a team at the University of South Florida Health (USF Health) Morsani College of Medicine and the University of Alabama at Birmingham. The researchers wanted to delineate potential differences in the immune-responsive processes needed to safely clear (resolve) acute inflammation after heart attack-induced tissue injury, with the aim of finding more individualized therapies for heart failure.

“Metabolic and leukocyte-responsive signaling control the acute inflammation needed for timely cardiac repair after a heart attack. But inflammation that is not cleared and remains long-term plays a key role in the pathology leading to heart failure,” said lead author Ganesh Halade, PhD, associate professor of cardiovascular sciences at the Morsani College of Medicine and a member of the USF Health Heart Institute.

“Understanding race and sex-based differences in inflammation and its resolution will help us develop more personalized diagnoses and treatments to delay or prevent heart failure.”

A mouse model study published by Dr. Halade last month discovered that heart repair occurs faster in female mice than males after a heart attack, which improves survival and delays cardiac failure.

In this human study, the researchers collected blood plasma from 53 patients, grouped by race and sex, within 24 to 48 hours after a heart attack. Baseline acute injury caused by the heart attack was similar in all the patients, and so were their ages and body mass indexes. No significant sex-or race-specific differences were detected in total cholesterol, HDL, LDL or triglyceride levels – all indicators (biomarkers) currently used by clinicians to help predict risk and manage cardiovascular disease. Measures of various subtypes of leukocytes (cells that regulate immune fitness) were similar across all patients.

Lead author Ganesh Halade, PhD, associate professor of cardiovascular sciences, USF Health Morsani College of Medicine

Looking for distinct bioactive lipid “signatures,” or inflammatory biomarkers, that might predict poorer cardiovascular outcomes after heart attack, the researchers measured three major polyunsaturated fatty acids: arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). These omega fatty acids circulate in blood and depend upon what people eat. Also analyzed were dozens of specific proresolving mediator (SPM) indicators and a few other signaling molecules that form when these fatty acids metabolize in response to immune activation.

Overall, black patients showed higher concentrations of the three activated fatty acids after a heart attack than white patients, the researchers found. The comparative analyses of SPMs showed that resolvin E1, a potent proresolving mediator of inflammation derived from the fatty acid EPA, was significantly lower in black men and women than in whites. An earlier major clinical trial linked EPA with reduced ischemic events such as heart attack and stroke in patients with high risk for, or existing, cardiac disease, and another showed that high levels of EPA significantly decreased the risk of heart failure.

The researchers conclude that bioactive lipids are key for diagnosis and treatment of cardiac repair after heart attack to delay heart failure.

Randomized controlled clinical trials will be needed to definitively determine whether distinct SPM signatures can be used to predict, diagnose, treat or prevent heart failure following a heart attack, Dr. Halade said. “If we can stratify risk among larger patient groups to determine who is deficient in SPMs critical for cardiac repair, we may be able to restore those targeted SPMs to improve outcomes.”

The study was supported by grants from the National Institutes of Health.

Heart failure affects about 6.5 million adults nationwide and leads to one in 8 deaths each year, according to the Centers for Disease Control and Prevention. The condition usually develops as the heart gradually loses its ability to pump enough blood through the body.

A University of South Florida-led study of mouse cardiac healing may lead to more precise, sex-specific therapies for heart failure, a leading cause of death

TAMPA, Fla. (April 17, 2020) –  The short-term acute inflammatory response triggered to mend injured cardiac tissue following a heart attack can lead to weakening of the heart’s pumping function if the inflammation remains active over the long-term. Heart failure associated with this unresolved chronic cardiac inflammation has become a leading cause of death in the U.S. and worldwide, yet little is known about the differences in cardiac repair and safe clearance of inflammation between men and women.

Ganesh Halade, PhD, an associate professor of cardiovascular sciences at the University of South Florida Health (USF Health) Morsani College of Medicine and Heart Institute, looks for ways to delay or prevent heart failure — including targeted therapies that may account for potential physiological sex differences.

Ganesh Halade, PhD

Dr. Halade’s team delves into the details of metabolic and leukocyte responsive signaling that facilitate cardiac repair during acute inflammation after injury (like a heart attack) and the resolution thereafter. In particular, he studies how unresolved inflammation driven by a deficiency in fatty acid-derived signaling molecules influences heart failure. Known as specialized proresolving mediators (SPMs), these molecules are naturally made by the body (endogenous).

Now, a new study led by Dr. Halade has investigated the molecular and cellular processes underlying cardiac repair in male and female mice after a severe heart attack. The USF Health study, conducted with collaborator Charles N Serhan, PhD, DSc, at Harvard Medical School, reports that females showed improved heart failure survival characterized by differences in cardiac functional recovery and structure, more reparative immune cells and higher levels of epoxyeicosatrienoic acids (EETs), signaling molecules with anti-inflammatory effects.

The findings were published April 16 in the Journal of the American Heart Association.

“We discovered heart repair happens faster in the female mice than the males after heart attack, that improves survival and delays cardiac failure,” said Dr. Halade, the paper’s senior author.

His ongoing translational work may have applications for the development of sex-specific and other more precise heart failure therapies with fewer side effects due to endogenous nature of bioactive signaling molecules. Currently, men and women receive the same standard first-line medications (angiotensin converting enzyme/receptor inhibitors, diuretics, and beta-blockers) to manage mild-to-severe forms of heart failure.

For this study appearing in JAHA, the researchers used “risk-free” young, healthy mice to control for variable cardiovascular risk factors — such as obesity, insulin resistance, diabetes, hypertension and aging, — common in a clinical setting. They compared the risk-free male and female mice who underwent a procedure to induce severe heart attack with those that did not.

To frame the study, it helps to know that physiological inflammation after tissue injury has two steps — an acute response, where white blood cells rush to the heart to remove dead cardiac tissue, and a resolving phase, where inflammation is cleared with the help of macrophages that arrive to repair the damage, and form stable scar. Both responses are governed by ‘get in’ and ‘get out’ signals to leukocytes (a type of immune cell) infiltrating at the site of the heart muscle injured by the heart attack.

Among the key USF Health research findings:

• Following a heart attack, leukocyte infiltration to clear diseased cardiac muscle cells is coordinated by the production of SPMs that resolve inflammation and promote timely cardiac repair.
• Female mice showed better recovery of the heart’s capacity to pump blood compared to males. “Improvement in heart functional recovery is believed to be enabling the female mice to ‘bounce back’ and survive at a significantly higher rate than male mice after myocardial infarction (heart attack),” the authors wrote.
• Less post-MI scarring and adverse structural remodeling of heart muscle in female mice helps explain their improved recovery of cardiac function and survival in acute and chronic heart failure.
• While both male and female mice equally produced SPMs in response to massive heart attacks, the females generated higher levels of a particular lipid signaling molecule known as epoxyeicosatrienoic acid (EET) to facilitate healing after a heart attack.

“The beauty of these SPM and EET molecules is that they are endogenously biosynthesized and can be useful for clearing harmful inflammation in asthma and other diseases, not just heart failure,” Dr. Halade said.

The USF Health researchers plan to study these bioactive lipid signaling molecules after heart attack in men and women, and consider human-related variable factors absent in mice, such as race.

The study was supported by grants from the NIH’s National Institute of Heart Lung and Blood Institute (Dr. Halade) and the National Institute of General Medical Sciences (Dr. Serhan).

The University of South Florida-led study is another step toward more effective treatments for a population disproportionately affected by this chronic cardiovascular disease

TAMPA, Fla. (March 7, 2018) — Heart failure is more common, develops earlier and results in higher rates of illness and death in African Americans than in whites.

Now, the first genetic study of its kind to examine the genetic basis of heart failure in African Americans, led by the University of South Florida (USF), Tampa, Fla., has identified a genetic variation linked specifically to heart failure in this population.  The discovery could lead to more precise and effective treatments for African Americans, who are more likely to suffer from a common form of heart failure of unknown cause called idiopathic dilated cardiomyopathy (IDC). IDC is a condition in which the heart weakens, cannot pump blood properly and becomes progressively enlarged.

The National Institutes of Health-funded study was published Feb. 26 in the Journal of Personalized Medicine.

“We know that this form of heart failure has a worse prognosis in African Americans and does not respond as effectively to most therapies as compared to the same treatments in Caucasian individuals of European descent. Yet, there had never been a genome-wide association study performed exclusively in African Americans,” said senior author and project director Stephen B. Liggett, MD, professor of internal medicine and vice dean for research at the USF Health Morsani College of Medicine.

“We undertook this study because of the severe under-representation of African Americans in these types of trials, and, our idea that the genetic causes might be different in this population,” added Dr. Liggett, a member of the USF Health Heart Institute. “Our genome-wide analysis suggests that is indeed the case, and we may need to develop new drugs to target IDC in African Americans.”

The Genetics of African American Heart Failure consortium examined genetic variations in the genomes of 662 African-American patients recruited from five U.S. academic medical centers:  the University of Cincinnati College of Medicine, Duke University School of Medicine, Johns Hopkins University School of Medicine, University of Maryland College of Medicine, and the Virginia Commonwealth University School of Medicine. All the study participants had no history of heart attacks and were diagnosed with IDC.

The researchers found that a variation in one gene, called CACNB4, could contribute to causing IDC in African Americans.  That same genetic defect has not been found in white patients with IDC. More study is needed, Dr. Liggett said, but CACNB4 plays a key role in regulating calcium signaling important for cardiac muscle contraction, so a variation that interferes with the gene’s function may lead to diminished pumping of blood by the heart.

In addition, variations in other genes suggested an association with IDC in individuals with African-American ancestry.  So, the researchers mapped the biochemical pathways of these 1,000 genes, which created a network indicating the potential action by which these variations lead to IDC, and possible targets for new drugs.  The consortium’s analysis showed that genetic variations in African Americans account for 33 percent of the risk for IDC.   And, many genes forming the pathway map were involved in how calcium regulates the work of heart muscle cells.

Dr. Liggett and his collaborators use various research methods, including examining genetic variation in different ethnic groups, with the aim of understanding how to best devise new drugs for treatment or prevention of heart failure. “Every time we perform these genetic studies, we learn something new and find another piece of the puzzle,” he said, “Ultimately the dissection of this cardiovascular disease will lead to drugs that strike at damaging pathways with a high level of precision, resulting in personalized medicine for heart failure.”

Nearly 6 million people in the United States have heart failure, a figure projected to increase to 8 million by 2030, according to the American Heart Association.  The five-year mortality rates range from 30 to 50 percent, greater than for some cancers.

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USF Health’s mission is to envision and implement the future of health. It is the partnership of the USF Health Morsani College of Medicine, the College of Nursing, the College of Public Health, the College of Pharmacy, the School of Physical Therapy and Rehabilitation Sciences, the Biomedical Sciences Graduate and Postdoctoral Programs, and the USF Physicians Group. The University of South Florida, established in 1956 and located in Tampa, is a high-impact, global research university dedicated to student success. USF is ranked in the Top 30 nationally for research expenditures among public universities, according to the National Science Foundation. For more information, visit www.health.usf.edu

Studies led by USF’s Dr. Stephen Liggett shed light on genetic variability of adrenergic receptors and how they might best be used to treat disease

Dr. Stephen Liggett, who leads the research enterprise for the Morasani College of Medicine and for USF Health, also oversees a genomics laboratory working on NIH-funded studies. Behind him is a radioligand binding machine used to determine the number of receptors in each cell.

While significant progress has been made managing asthma over the last two decades, about half of all asthmatics achieve optimal control of this chronic inflammatory disease using currently available medications.  Similarly, only about 50 percent of patients with congestive heart failure, which occurs when the heart is too weak to pump enough blood to meet the body’s needs, have an average life expectancy of more than five years.

More still needs to be  known at the molecular level about these common diseases to identify potential new targets for drug therapies, said Stephen B. Liggett, MD, associate vice president for research at USF Health, vice dean for research at the Morsani College of Medicine, and professor of internal medicine and molecular pharmacology and physiology.

What ties these two diseases together are the receptors on cardiac muscle and on smooth muscle of the airways. Dr. Liggett’s laboratory helps shed light on the genetic variability of adrenergic receptors and on how these receptors can best be used for treatment. The genetic studies have been particularly useful in developing the concept of pharmacogenetics, a tailoring of therapy based on an individual’s genetic makeup, for heart failure and asthma.

“Twenty years ago we had a handful of medicines for high blood pressure, and today we don’t use any of them. Now, we have a whole new group of more effective (antihypertensive) drugs with much fewer side effects,” he said.  “And, I’m sure that one day, we’ll have more tools in our toolbox to better treat heart failure and asthma – drugs that work better for subgroups of people as defined by their genetic makeup and environmental exposures.”

 Dr. Liggett comments on some of his laboratory’s contributions to the field over his career.

The research team led by Dr. Liggett, center, includes Ashley Goss, Hiwot Zewdie, Donghwa Kim, PhD, and Maria Castano. Not pictured: Alexa Woo, PhD.

Mining a “superfamily” of receptors for better drug targets

Dr. Liggett leads a USF team that studies the genetic, molecular biology, structure and function of G-coupled protein receptors, or GPCRs, the largest family of human proteins.  More than 800 GPCRs have been discovered within cell membranes in the human body, Dr. Liggett said, and one or more of these receptors plays a role in virtually everything the body does, including controlling thoughts in the brain, sight and smell, uterine contraction and relaxation, blood pressure, cardiac, lung and kidney function, to name just a few.

Consequently, malfunctions of GPCR signaling pathways are implicated in many chronic diseases including asthma and cardiovascular diseases.  Already this “superfamily” of receptors accounts for nearly half the targets of all prescribed drugs. But, a deeper understanding of the dynamics of the GPCR signaling network and how it maintains a healthy cell or responds to pathogens could lead to the design of drugs that more precisely target diseases with greater effectiveness and fewer side effects.

Dr. Liggett began his work with GPCRs in 1988 as a Howard Hughes Institute postdoctoral research fellow in the Duke University Medical Center laboratory of mentor Robert Lefkowitz, MD. Dr. Lefkowitz was awarded the 2012 Nobel Prize in Chemistry with Brian Kobilka, MD, for groundbreaking discoveries revealing the inner workings of GPCRs.

Building upon his interest and advanced training in pulmonary and critical care medicine, Dr. Liggett began early in his career to concentrate on one of the classes of GPCRs known as adrenergic receptors, which are stimulated by the hormone epinephrine and the neurotransmitter norepinephrine. They are involved in increasing the rate and force of contraction of the heart, as well as constriction and dilation of blood vessels throughout the body and of airways in the lung. For the last 28 years, he has been continuously funded by the National Institutes of Health (NIH) to study the molecular basis of beta-adrenergic receptors in asthma.

Biological scientist Ashley Goss

Dr. Liggett is the principal investigator of a four-year, $1.12-million R01 grant from the NIH’s National Heart, Blood and Lung Institute (NHBLI) that seeks to understand how beta-adrenergic signaling is regulated to influence the development and treatment of asthma. Over his career, he has also been awarded millions of dollars in NIH funding to explore the role of genetic variations of GPCRs in heart failure, including whether those variations may alter how effectively drugs work in individual patients.

Bitter taste receptors in a new place

Dr. Liggett is also currently a project principal investigator for a five-year, $2-million NHBLI P01 grant examining how airway smooth muscle bitter taste receptors might be applied as new treatments for asthma and chronic obstructive pulmonary disease.

Using a genomics-based method that Dr. Liggett pioneered, his team had previously identified bitter taste receptors, initially thought only to exist on the tongue, deep inside the lung at the airway smooth muscle and demonstrated they act to open the airway. “When activated, they appear far superior to the beta-agonists commonly prescribed to patients to open their airways during an asthma attack,” said Dr. Liggett, who published the discovery and the need for alternatives to current bronchodilators in Nature Medicine and other journals.

Overall, discoveries emerging from Dr. Liggett’s research have yielded more than 250 peer-reviewed papers, many highly cited and appearing in top journals such as Nature Medicine, Science, Proceedings of the National Academy of Sciences, and the New England Journal of Medicine. His work has been cited by other papers more than 26,000 times. He also holds 18 patents detailing potential new targets for drug therapy or genetic variations of known drug targets and how they might be used to predict response to medications and customize treatment.

 The serendipity of finding bitter taste receptors on smooth airway muscle in the lungs

Laboratory assistant Hiwot Zewdie

Among some of his laboratory’s major findings:

– While at the University of Maryland, Dr. Liggett’s team worked with colleagues at the University of Wisconsin-Madison to sequence for the first time the entire genomes (more than 100 different strains) of all known rhinoviruses, a frequent cause of respiratory infections including the common cold. The groundbreaking work, published on the cover of Science, provided a powerful framework for large-scale, genome-based epidemiological studies and the design of antiviral agents or vaccines to combat rhinoviruses. “I originally suggested sequencing 10 strains, and then my collaborator asked why not do them all,” he said. “This made the difference between a mediocre proof-of-concept paper and a full article in Science. I learned that it is important to think big if you want to make a real difference”

–  Discovered and characterized genetic variations that may predict which patients with congestive heart failure respond best to a life-saving beta-blocker drug.  These landmark studies occurred over several years and were published in Nature Medicine twice, and the Proceedings of the National Academy of Sciences three times. “This is a good example of the progression of an idea over time, where every year or so an unexpected turn of events occurred, and new insight was gained,” he said.

– While at the University of Cincinnati, Dr. Liggett, working with colleagues at Washington University and Thomas Jefferson University, found that a genetic variation of an enzyme, which inhibits beta-adrenergic receptor signaling, confers “genetic beta-blockade” in cardiac muscle and protects against early death in African Americans with heart failure.  The findings, published in Nature Medicine, provided insight into individual variations in disease outcomes. Another key study from Cincinnati revealed that a certain combination of genetic variants within a single gene conferred low vs. excellent responses to inhaled beta-agonists in treating asthma. These combinations, called haplotypes, had never been identified in GPCRs. The work was published in Proceedings of the National Academy of Sciences.

Dr. Liggett’s groundbreaking research sequencing all known human rhinoviruses, a frequent cause of respiratory infections, was featured on the April 3, 2009 cover of the journal Science.

Advancing outside his field of study

Dr. Liggett joined USF Health in 2012 from the University of Maryland School of Medicine in Baltimore, where he was associate dean for interdisciplinary research and professor of medicine and physiology. He received his MD degree at the University of Miami and completed both a residency in internal medicine and fellowship in pulmonary diseases and critical care medicine at Washington University School of Medicine and Barnes Hospital in St. Louis, MO.

Within two years, he advanced from a postdoctoral research fellowship in Dr. Lefkowitz’s laboratory at Duke to tenured associate professor and director of pulmonary and critical care medicine at the University of Cincinnati College of Medicine.  By the time he left Cincinnati for the University of Maryland in 2005, he held an endowed chair in medicine and directed the university’s Cardiopulmonary Research Center.

Though he had no significant wet-lab experience, Dr. Liggett was fascinated by the emerging science called “molecular biology” and was undeterred from branching into a field of study in which he had no formal training.

He secured a position as assistant professor at Duke following his fellowship there, and figured out how to sequence adrenergic receptor genes from a patient’s blood. While routine now, such genetic testing had not been done previously.  He unexpectedly kept finding multiple variations (called polymorphisms or mutations) in genes coding for the same receptors, so he sought out the advice of some classic geneticists.  At the time, Dr. Liggett said, their traditional thought was modeled after diseases like cystic fibrosis — if a person had the genetic mutation they developed the disease, if the mutation was absent they did not.

“There was no consideration for common genetic variants and how they might affect disease risk, progression, or response to treatment. It simply was not in their thought process,” Dr. Liggett said. He was told “it’s probably nothing and don’t quit your day job.” He did not take their advice.

 Some advice Dr. Liggett would give to emerging young scientists

Assistant professor Donghwa Kim, PhD

Instead, he returned to the laboratory to sequence and clone receptors from many different populations with asthma and heart failure, showing that the receptor genes did indeed differ from one individual to another, generally with several common “versions.” His team also created “humanized” mice expressing the human genes for asthma and heart failure so they could begin to understand the physiology of the receptors. They began to find that some genetic alterations increased receptor function, some decreased the drug’s affinity to bind (responsiveness) to a receptor, and still others altered how the receptor was regulated.  And, through NIH-supported clinical trials, the researchers correlated outcomes observed in patients undergoing drug therapies with the genetic variations uncovered in the laboratory.

“If there’s a lesson to be learned here by young investigators, I’d say it’s that you can collect information from experts in the field, but you need to use your gut to ultimately decide on whether to pursue a line of research or not,” Dr. Liggett said.

Personalized medicine challenge: Common diseases, multiple genetic variations

Realizing personalized medicine’s full potential will require a better understanding of how environmental variables – including diet, exercise, the gastrointestinal microbiome (gut bacteria) and toxin exposure – combine with genetic variations to affect disease and its treatment, he said. “Personalized medicine faces its greatest challenges in the common diseases like asthma, atherosclerotic heart disease and heart failure, because they involve multiple variations in multiple genes that interact with the environment to give you a disease – and also provide a set-up for unique ways to treat the disease.”

Biological scientist Maria Castano

Dr. Liggett was one of the first physicians recruited for what would become the USF Health Heart Institute.  He recalls that he still had the letter of offer in his pocket when he stood before the Hillsborough County Commission in 2012 to help USF Health leadership pitch the need for a cardiovascular institute to include a focus on genomics-based personalized medicine.  The county joined the state in funding the project, and Dr. Liggett was instrumental in the early planning stages of the Heart Institute before the arrival of its founding director Dr. Samuel Wickline.  The institute is now under construction in downtown Tampa as part of the new Morsani College of Medicine facility, a key anchor of Water Street Tampa. Already, 21 of the 31 institute’s biomedical scientists who will investigate the root causes of heart and vascular diseases with the aim of finding new ways to detect, treat and prevent them, have been recruited.

“There’s an excitement here and philosophy of excellence that’s rewarding to see,” Dr. Liggett said. “We have a strategic plan in place, including moving ahead to expand research in cardiovascular disease, infectious disease and the microbiome, and the neurosciences. Our departments are recruiting at a good pace, and the faculty we’re bringing in all have NIH funding and are highly collaborative.”

Dr. Liggett is an elected fellow of the American Association for the Advancement of Science – one of only five Morsani College of Medicine faculty members to receive that prestigious honor.  He is also an elected Fellow of the National Academy of Inventors and the American College of Chest Physicians. Last year, he was one of 30 scientists nationwide selected to join The Research Exemplar Project – recognition of his outstanding reputation as a leader whose high-impact, federally-funded research yields novel and reproducible results.

Over his career, he has served on several NIH study sections and on the editorial board of high-impact journals relevant to fundamental biochemistry as well as heart and lung diseases.  He is currently editor-in-chief of the Journal of Personalized Medicine.

 The potential of new treatments for asthma and heart failure

Dr. Liggett holds 18 patents detailing potential new targets for drug therapy or genetic variations of known drug targets, which might be used to predict response to medications and customize treatment.

Some things you may not know about Dr. Liggett:

• He has asthma, which helps motivate his research toward finding better treatments for this common lung disease affecting one in 12 people in the United States.
• Restores vintage cars, primarily DeLoreans. Although he recently finished bringing a funky lime green 1974 Volkswagen Thing back to life, and over the holidays restored a 1973 VW camper. 

• Lives with wife Julie on the beach in Treasure Island, where they enjoy surfing, paddle boarding, and photography.
• Has three children – Elliott, an engineer at NASA’s Jet Propulsion Laboratory at Cal Tech in Pasadena, CA; Grace, who recently completed her master’s degree in public health at USF; and Mara, an undergraduate student studying social work at Florida Atlantic University, and two step-children — Madison, an undergraduate at the University of Florida, and Tripp, a senior at St. Petersburg Catholic High School. He also has three grandchildren, ages 2 to 9.

Photos by Sandra C. Roa, and audio clips by Eric Younghans, University Communications and Marketing

Personalized medicine research at University of South Florida strikes early for heart genes 

Tampa, FL (Oct. 16, 2012) — A landmark paper identifying genetic signatures that predict which patients will respond to a life-saving drug for treating congestive heart failure has been published by a research team co-led by Stephen B. Liggett, MD, of the University of South Florida.

The study, drawing upon a randomized placebo-controlled trial for the beta blocker bucindolol, appears this month in the  international online journal PLoS ONE.  In addition to Dr. Liggett, whose laboratory discovered and characterized the two genetic variations, Christopher O’Connor, MD, of Duke University Medical Center, and Michael Bristow, MD, PhD, of ARCA biopharma and the University of Colorado Anschutz Medical Campus, were leading members of the research team.

Dr. Stephen Liggett, who joined USF just four months ago to lead the University’s Center for Personalized Medicine and Genomics, was a senior author of the landmark paper.

The analysis led to a “genetic scorecard” for patients with congestive heart failure, a serious condition in which the heart can’t pump enough blood to meet the body’s needs, said Dr. Liggett, the study’s co-principal investigator and the new vice dean for research and vice dean for personalized medicine and genomics at the USF Morsani College of Medicine.

“We have been studying the molecular basis of heart failure in the laboratory with a goal of finding genetic variations in a patient’s DNA that alter how drugs work,” Dr. Liggett said.  “We took this knowledge from the lab to patients and found that we can indeed, using a two-gene test, identify individuals with heart failure who will not respond to bucindolol and those who have an especially favorable treatment response. We also identified those who will have an intermediate level of response.” The research has implications for clinical practice, because the genetic test could theoretically be used to target the beta blocker to patients the drug is likely to help. Equally important, its use could be avoided in patients with no likelihood of benefit, who could then be spared potential drug side effects.  Prospective studies are needed to confirm that bucindolol would be a better treatment than other classes of beta blockers for a subset of patients with health failure.

Dr. Liggett collaborated with medical centers across the United States, including the NASDAq-listed biotech company ARCA biopharma, which he co-founded in Denver, CO.   This genetic sub-study involved 1,040 patients who participated in the Beta-Blocker Evaluation of Survival Trial (BEST).  The researchers analyzed mortality, hospital admissions for heart failure exacerbations and other clinical outcome indicators of drug performance.

“The results showed that the choice of the best drug for a given patient, made the first time without a trial-and-error period, can be accomplished using this two-gene test,” Dr. Liggett said.

The genetic test discovered by the Liggett team requires less than 1/100^th of a teaspoon of blood drawn from a patient, from which DNA is isolated.  DNA is highly stable when frozen, so a single blood draw will suffice for many decades, Dr. Liggett said. And since a patient’s DNA does not change over their lifetime, as new discoveries are made and other tests need to be run, it would not be necessary to give another blood sample, he added.

This is part of the strategy for the USF Center for Personalized Medicine and Genomics. The discovery of genetic variations in diseases can be targeted to predict three new types of information: who will get a disease, how the disease will progress, and the best drug to use for treatment.

“In the not too distant future, such tests will become routine, and patient outcomes, and the efficiency and cost of medical care will be impacted in positive ways.  We also will move toward an era where we embrace the fact that one drug does not fit all,” Dr. Liggett said.  “If we can identify by straightforward tests which drug is best for which patient, drugs that work with certain smaller populations can be brought to the market, filling a somewhat empty pipeline of new drugs.”

This approach is applicable to most diseases, Dr. Liggett said, but the USF Center has initially concentrated on heart disease, because it is a leading cause of deaths, hospitalizations and lost productivity in the Tampa Bay region and Florida.  Dr. Liggett is a recent recruit to the USF Health Morsani College of Medicine, coming from the University of Maryland School of Medicine.  His work at USF has been supported by several National Institutes of Health grants and $2 million in funding from Hillsborough County.

Heart failure is characterized by an inability of the heart muscle to pump blood, resulting in dysfunction of multiple organs caused by poor blood and oxygen flow throughout the body.  An estimated 6 million Americans are living with heart failure, and more than half a million new cases are diagnosed each year.  About 50 percent of patients diagnosed with heart failure die within five years.  The economic burden of heart failure in the United States is estimated at $40 billion a year.

Article citation:
Christopher M. O’Connor, Mona Fiuzat, Peter E. Carson, Inder S. Anand, Jonathan F. Plehn, Stephen S. Gottlieb, Marc A. Silver, JoAnn Lindenfeld, Alan B. Miller, Michel White, Ryan Walsh, Penny Nelson, Allen Medway, Gordon Davis, Alastair D. Robertson, J. David Port, James Carr, Guinevere A. Murphy, Laura C. Lazzeroni, William T. Abraham, Stephen B. Liggett and Michael Bristow, “Combinatorial Pharmacogenetic Interactions of Bucindolol and β₁, α_2C Adrenergic Receptor Polymorphisms,” PLoS ONE   7(10): e44324. doi:10.1371/journal.pone.0044324

-USF Health-

USF Health’s mission is to envision and implement the future of health. It is the partnership of the USF Health Morsani College of Medicine, the College of Nursing, the College of Public Health, the College of Pharmacy, the School of Biomedical Sciences and the School of Physical Therapy and Rehabilitation Sciences; and the USF Physician’s Group. The University of South Florida is a global research university ranked 50^th in the nation by the National Science Foundation for both federal and total research expenditures among all U.S. universities.

Media contact:
Anne DeLotto Baier, USF Health Communications
(813) 974-3303 or abaier@health.usf.edu