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Hard Hearts



Many of us know that as people age, they become crankier. You might have that 85-year-old neighbor who refuses to let your dog on her lawn. You might have the penny-pinching grandma who holds up the line at the grocery store as she disputes why her twenty cents off a gallon of milk coupon was rejected. You have that old man in his 1998 Buick LeSabre who refuses to move out of the fast lane on the highway. It is very true that as people age, their heart hardens–literally.

According to Arjun Deb, a researcher at the University of Southern California, “The cardiovascular system is one soft tissue that gets calcified very easily.” This hardening of the heart might be a buildup of calcium in the blood vessels and tissues that compose the heart. The theory is that the calcification of the heart can be a result of many previous medical conditions in a patient, including diabetes, smoking, and cancer. However, studies have focused primarily on fibroblasts, which are the connective tissues in between cells; they are instrumental in healing wounds. After a tissue is injured or torn, fibrocyte cells in the vicinity become fibroblasts in order to restore the connective tissue in the affected area. Researchers believe that the calcification of these new fibroblasts causes the heart to harden because sometimes, these fibroblasts mutate and act more like osteoplasts, or bone tissue.

Studies have also shown that as the heart calcifies, more and more cells around it also start calcifying. These tests were primarily done on mice, which received various injuries to heart tissue. As bone-like fibroblasts formed, the tissue was removed and transferred onto the skin of healthy mice; their skin calcified within a month. In lab dishes, human cells gave the same results, which shows that the presence of these hard ossified tissues nearby can cause other cells nearby to do the same thing.

With this information, we can further examine the chemical processes in the heart. After a fibroblast calcifies, one particular protein, ENPP1, is released. This protein is most likely an agent in the calcification of the tissue. To eliminate the hardening, osteoporosis medicine can be given to the patient. In labs, it was shown that after mice received this osteoporosis medication, the heart tissue showed no signs of hardening. Yet a major drawback of this medication is that it is preventative rather than curative. It works only if used before the calcification occurs, and therefore, will be of little use in humans as people will not know the exact moment when their heart begins to harden.

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Edited by: Ruby Halfacre and Karen Yung