Heart specialists at Johns Hopkins and elsewhere report what is believed to be the first wide-scale evidence linking severe overweight to prolonged inflammation of heart tissue and the subsequent damage leading to failure of the body’s blood-pumping organ.
The latest findings from the Multiethnic Study of Atherosclerosis (MESA), to be published in the May 6 issue of the Journal of the American College of Cardiology, appear to nail down yet one more reason for the estimated 72 million obese American adults to be concerned about their health, say scientists who conducted the research.
“The biological effects of obesity on the heart are quite profound,” says senior study investigator João Lima, M.D. “Even if obese people feel otherwise healthy, there are measurable and early chemical signs of damage to their heart, beyond the well-known implications for diabetes and high blood pressure.”
He adds that there is “now even more reason for them to lose weight, increase their physical activity and improve their eating habits.”
In the latest study, researchers conducted tests and tracked the development of heart failure in an ethnically diverse group of nearly 7,000 men and women, age 45 to 84, who were enrolled in the MESA study, starting in 2000.
Of the 79 who have developed congestive heart failure so far, 35 (44 percent) were physically obese, having a body mass index, or BMI, of 30 or greater. And on average, obese participants were found to have higher blood levels of interleukin 6, C-reactive protein and fibrinogen, key immune system proteins involved in inflammation, than non-obese adults.
A near doubling of average interleukin 6 levels alone accounted for an 84 percent greater risk of developing heart failure in the study population.
The researchers from five universities across the United States also found alarming links between inflammation and the dangerous mix of heart disease risk factors known as the metabolic syndrome. Its combined risk factors for heart disease and diabetes - high blood pressure, elevated blood glucose levels, excess abdominal fat and abnormal cholesterol levels, and particularly obesity - double a person’s chances of developing heart failure.
“More practically, physicians need to monitor their obese patients for early signs of inflammation in the heart and to use this information in determining how aggressively to treat the condition,” says Lima, a professor of medicine and radiology at the Johns Hopkins University School of Medicine and its Heart Institute.
All MESA study participants, who will be followed through to 2012, had no pre-existing symptoms of heart disease. Upon enrollment, they all underwent a physical exam, including weight and body measurements, blood analysis and an MRI scan to assess heart function.
“Our results showed that when the effects of other known disease risk factors - including race, age, sex, diabetes, high blood pressure, smoking, family history and blood cholesterol levels - were statistically removed from the analysis, inflammatory chemicals in the blood of obese participants stood out as key predictors of who got heart failure,” says Lima.
The chemicals are all known to be part of the body’s defensive response to disease. They are well-recognized for producing symptoms that stem from the widening of small blood vessels, including redness and fever, and the release of immune system cells that make blood vessels leak fluid into surrounding tissue, causing swelling and cell death. The inflammatory process eventually leads to cell damage and the buildup of scar tissue near the damaged areas.
In obese participants, interleukin 6, a chemical that activates white blood cells and drives inflammation, was higher than in non-obese participants.
Similarly, a near tripling of average levels of C-reactive protein in study participants increased the chance of heart failure by 36 percent.
C-reactive protein levels are widely known to rise dramatically and speed up the early stages of inflammation when cells swell up with fluid, leading to widespread arterial damage.
One-fifth higher than average blood levels of fibrinogen, best known for its role in blood clotting but also a major player in muscle scarring, bumped up the risk of heart failure by 37 percent.
When the inflammatory protein levels were included in the scientists’ statistical analysis, the heightened risk from obesity disappeared.
“What this tells us is that both obesity and the inflammatory markers are closely tied to each other and to heart failure,” says lead researcher Hossein Bahrami, M.D., M.P.H.
Each year, nearly 300,000 Americans die from heart failure.
Bahrami says study results also point to inflammation as a possible catalyst in metabolic syndrome. Increased blood levels of albuminuria, a chemical more known for its association with impaired kidney function and metabolic syndrome boosted risk of a progressively weakening heart nearly tenfold among MESA participants.
Bahrami, a senior cardiology research fellow at Hopkins, says “the basic evidence is building the case that inflammation may be the chemical route by which obesity targets the heart, and that inflammation may play an important role in the increased risk of heart failure in obese people, especially those with the metabolic syndrome.”
He notes that previous studies, also done at Hopkins, have shown that even moderate exercise to lose abdominal fat dramatically offsets the harmful effects of metabolic syndrome on heart function.
Bahrami says the team’s next steps are to determine how, over a longer timeframe, heart function changes with levels of inflammatory markers, and to see if alterations to the immune system proteins halts or speeds up disease.
WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf
First form of therapy for childhood dementia CLN2 developed
25.04.2018 | Universitätsklinikum Hamburg-Eppendorf
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology