Atherosclerosis -- the build-up of plaque in arteries, raising the risk for heart disease -- may not form the way we previously thought, according to a new study.


The discovery could change the way we treat cardiovascular disease, the leading cause of death[1] in the U.S. and around the world, researchers noted.


Research[2] from the University of Toronto and Massachusetts General Hospital, found that macrophages[3] -- white blood cells in tissue associated with inflammation -- replicate within the plaques to cause atherosclerosis[4] . Scientists originally thought the inflammatory macrophages collected mainly with the support of monocytes[5] -- white blood cells that respond to pathogens -- from the bloodstream.


“Our study shows that the accumulation of macrophages also depends on their proliferation locally within the developing plaque,” study researcher Clint Robbins, assistant professor in the laboratory medicine and pathobiology departments at the University of Toronto, said in a statement.


The new understanding of how macrophages reproduce within the plaque calls for the re-evaluation of current atherosclerosis therapy. Research has been concentrated on therapies that would block white cells from getting into the plaques, but not the growth of cells within the plaque.


Statin therapy is now used to lower blood lipids that contribute to plaque. With more research, scientists may use statins -- which also have anti-inflammatory properties -- to limit the spread of macrophages within the plaques.


Results of the study, published in the journal Nature Medicine, are based on mice subjects. More research is needed to know if findings are relevant to humans, though researchers did find evidence of macrophage growth in plaque on human carotid arteries. Scientists are interested in further finding if all macrophages or only subsets replicate within the plaque.




Loading Slideshow...



  • 1. Not Smoking


    While not entirely surprising, it doesn't make the message any less important: <a href="http://www.nhlbi.nih.gov/health/health-topics/topics/smo/" target="_hplink">Smoking kills</a>. The habit is considered the No. 1 cause of preventable death and sickness in the U.S.

    Specifically, <a href="http://www.nhlbi.nih.gov/health/health-topics/topics/smo/" target="_hplink">smoking cigarettes harms the heart</a> in that it damages heart and blood vessel function, thereby upping the risk of atherosclerosis (where your arteries harden), according to the National Institutes of Health.




  • 2. Being Physically Active


    Aerobic exercise is good for the heart in that it makes you take in more oxygen, helps you <a href="http://www.mayoclinic.com/health/aerobic-exercise/EP00002/NSECTIONGROUP=2" target="_hplink">keep to a healthy weight</a>, reduces plaque buildup in the arteries and helps to lower blood pressure, according to the Mayo Clinic.

    According to the Centers for Disease Control and Prevention, adults are recommended to get at least <a href="http://www.cdc.gov/physicalactivity/everyone/guidelines/adults.html" target="_hplink">150 minutes of aerobic exercise</a> a week (moderate to intense level), and also do muscle-strengthening at least twice a week.




  • 3. Maintaining Normal Blood Pressure Levels


    <a href="http://www.nhlbi.nih.gov/hbp/bp/bp.htm" target="_hplink">Blood pressure measurements</a> are written in terms of systolic over diastolic. Systolic pressure is "as the heart beats," according to the National Institutes of Health, while diastolic pressure is the relaxation of the heart between heartbeats.

    A person with a normal blood pressure level has a systolic blood pressure reading of 120 millimeters of mercury or less, and a diastolic blood pressure reading of 80 millimeters of mercury or less.

    A person is <a href="http://www.nhlbi.nih.gov/hbp/detect/categ.htm" target="_hplink">considered hypertensive</a> (has high blood pressure) when the systolic blood pressure is between 140 and 159, and the diastolic blood pressure is between 90 and 99.




  • 4. Maintaining Normal Blood Glucose Levels


    Having chronically <a href="http://diabetes.webmd.com/blood-glucose" target="_hplink">high levels of glucose</a>, a kind of sugar, in the blood can lead kidney and blood vessel damage, according to WebMD.

    Insulin, a hormone in the body, is responsible for helping the body's cells to <a href="http://www.medicinenet.com/insulin/article.htm" target="_hplink">use glucose in the blood</a>. However, if the body doesn't have enough insulin or isn't able to use it properly, then <a href="http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hyperglycemia.html" target="_hplink">blood sugar levels may rise</a>, according to the American Diabetes Association. High blood sugar is considered a diabetes complication.

    Tests to check for high blood glucose can help show whether a person has diabetes, and are used to <a href="http://diabetes.webmd.com/blood-glucose" target="_hplink">monitor someone with diabetes</a> over time, WebMD reported.




  • 5. Maintaining Normal Total Cholesterol Levels


    <a href="http://www.nhlbi.nih.gov/health/public/heart/chol/wyntk.htm" target="_hplink">High cholesterol</a> is a known risk factor for heart disease, because it causes hardening of arteries going to the heart, according to the National Institutes of Health. When part of the heart is deprived of blood, it could trigger a heart attack.

    The <a href="http://www.nhlbi.nih.gov/health/public/heart/chol/wyntk.htm" target="_hplink">optimum total cholesterol level</a> is 200 or fewer milligrams of cholesterol per deciliter of blood, while having a total cholesterol level of 200 to 239 milligrams per deciliter is considered borderline high. High total cholesterol is having 240 milligrams of cholesterol per deciliter of blood, or more, according to the National Institutes of Health.




  • 6. Having A Healthy Weight


    Calculating your body mass index (BMI, a ratio of weight to height) is a good starting point for knowing if you're at a <a href="http://www.cdc.gov/healthyweight/assessing/index.html" target="_hplink">healthy weight</a>, according to the Centers for Disease Control and Prevention. According to the BMI chart, having a BMI of 18.5 or below is considered "underweight" and a BMI of 18.5 to 24.9 is considered "normal" or healthy weight. A BMI of 25 to 29.9 is considered overweight, and a BMI of 30 and above is considered obese.

    <a href="http://www.nhlbisupport.com/bmi/" target="_hplink">Click here to calculate your BMI</a>.

    <a href="http://www.cdc.gov/healthyweight/assessing/index.html" target="_hplink">Waist circumference</a> can also give clues to your weight; a man may be at risk for health problems from obesity if his waist circumference is more than 40 inches, the CDC reported. For a non-pregnant woman, it's more than 35 inches.




  • 7. Eating A Healthy Diet


    While there are obviously differences in opinion depending on who you ask as to what you should or shouldn't eat for optimal health, there are some <a href="http://www.mayoclinic.com/health/heart-healthy-diet/NU00196" target="_hplink">heart-healthy nutrition rules</a> that remain true across the board. The Mayo Clinic reports that eating a diet low in cholesterol and "bad" fats (saturated and trans fats), with low-fat proteins (like lean meats, fish and beans), whole grains (with lots of fiber), and little sodium is good for your heart.

    For more nutrition advice, <a href="http://www.mayoclinic.com/health/healthy-diet/NU00200" target="_hplink">click over to the Mayo Clinic</a>.




  • Related Video


    Follow a heart healthy diet to reduce your risk of coronary disease.