Images Link Psoriasis to Other Diseases
Despite many recent advances by specialists in understanding psoriasis, too many people, including some doctors, still believe that it is merely a skin problem. So says Dr. Nehal N. Mehta, whose latest research provides further evidence that psoriasis is more than skin deep.
Mehta, a preventive and nuclear cardiologist with the University of Pennsylvania Perelman School of Medicine, was lead author of a groundbreaking study, funded by the National Psoriasis Foundation, that used a sophisticated, highly advanced imaging technology to detect areas of inflammation in people with psoriasis.
As the researchers expected, the images did show inflamed skin and inflammation in blood vessels. But they were surprised to observe inflammation in other organs and joints in the patients with psoriasis, one of whom also had psoriatic arthritis. The evidence impressed Mehta and his associates, who believe the study provides further evidence that psoriasis and other inflammatory diseases are linked.
The images showed inflammation in the liver, joints, tendons and aorta, even though the study participants had no symptoms or apparent risk factors for diseases that affect those organs. The participants who did not have psoriasis did not show any increased inflammation in any of these locations.
The study, published in the Archives of Dermatology, adds to a growing body of evidence that people with psoriasis are at a higher risk for heart, joint and liver disease, even when they do not have any symptoms.
Mehta was especially interested to discover inflammation in the liver. "For the first time, a study showed liver inflammation is much higher in psoriasis patients when looking in real time," he said. This finding suggests why patients with psoriasis may have high cholesterol and blood sugars, as well as trouble with certain drugs, such as methotrexate or commonly used statin medications for cholesterol, which are metabolized by the liver.
For the study, Mehta's research team used a highly sensitive imaging technique called fluorodeoxyglucose positron emission tomography—computed tomography, or FDG-PET/CT, which produces images that detect the metabolic activity of tissues within the body. The study's purpose was to learn whether this technique could capture an image of inflammation beyond the skin in patients who have moderate to severe psoriasis to better understand why patients with psoriasis may be at higher risk for heart disease and diabetes.
The study produced two main findings. First, it showed that psoriasis as a disease affects the whole body, not just the skin (denoted by the arrows in the image on the previous page). It also showed that FDG-PET/CT imaging is effective for identifying inflammation in the blood vessels, joints and liver, as well as the skin of patients with psoriasis who have not yet shown symptoms of problems in these areas.
Mehta explains that FDG-PET/CT combines nuclear medicine—the branch of medicine that uses radiation and radioactive materials to diagnose and treat diseases—with two imaging technologies, PET and CT scans. It most frequently has been used for cancer imaging because this technique is able to show images of cancer cells, which are highly active, with great precision.
"This was a pilot study, meaning that it was the first attempt to test whether FDG-PET/CT can be used to detect inflammation in psoriasis and to understand if severe psoriasis affects critical organs beyond the skin," Mehta explained. "We have to keep in mind that the findings we report are based on a single study, and, thus, additional studies are necessary to confirm and extend our findings."
Commenting in Archives of Dermatology, University of Michigan researchers Drs. Johann E. Gudjonsson and Abhishek Aphale noted that, as one of the first studies to show objective evidence of inflammation in the blood vessels and liver of patients with psoriasis, Mehta's research "may eventually lead to earlier and more aggressive treatments and closer monitoring of patients with psoriasis."
Mehta says his next step in the research will be to test whether treating psoriasis with certain biologic drugs or with ultraviolet B phototherapy—treatments that reduce psoriasis inflammation—can also help calm inflammation throughout the body. He wants to understand whether these treatments will improve traditional and emerging risk factors for heart disease and diabetes.
He also hopes his research will raise awareness among medical providers who still consider psoriasis a cosmetic disease, and demonstrate the need to look beyond skin when confronting the disease.