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Raman spectroscopy reveals link between atherosclerosis, medial calcification
Raman spectroscopy quantified the distribution of specific mineral species, proteins and lipids in aortic tissue cross sections, according to a study published in Science Advances.
“We affirm that atherosclerosis is an aggravator of the aortic medial calcification,” Molly M. Stevens, PhD, professor of biomedical materials and regenerative medicine and the research director for biomedical material sciences in the Institute of Biomedical Engineering at Imperial College London, and colleagues wrote. “The difference in the mineral population in medial calcification in conjunction with atherosclerosis suggests a distinct mechanism compared to medial calcification in aging.”
The researchers analyzed Raman spectroscopy imaging of 41 tissues from 31 patients, including 10 patients without atherosclerosis younger than 50 years (average age, 27 years; male/female ratio = 0.67), nine patients without atherosclerosis older than 50 years (average age, 58 years; male/female ratio = 1.25), 12 patients with atherosclerotic nonplaque (average age, 57 years; male/female ratio = 0.5) and 10 patients with atherosclerotic plaque (average age, 57 years; male/female ratio = 0.43).
Patients with atherosclerotic plaque had levels of apatite, cholesterol and triglycerides at least five times higher compared with those in other groups (P < .01).
Whitlockite was mostly present in the aortic media (P < .01) and apatite was predominantly present in the aortic intima/plaque (P < .05) in patients without atherosclerosis younger than 50 years and those with atherosclerotic plaque.
“The results indicate that there is a significant increase of whitlockite relative to apatite in the aortic media with age, which is reversed by the presence of atherosclerotic plaque in the directly underlying media,” Stevens and colleagues wrote.
Low levels of beta-carotene were seen in both groups of patients with atherosclerotic plaque compared with patients without atherosclerosis younger than 50 years (P < .05). Levels were similar in both groups without atherosclerotic plaque.
“Our results indicate that in the event of atherosclerosis, a local change in the tissue environment is elicited that promotes the disproportionate accumulation of apatite within the atherosclerotic plaque and the directly underlying media,” Stevens and colleagues wrote. “This local phenomenon does not change the whitlockite-to-apatite ratios in the rest of the tissue, although it affects the aortic media directly underlying the plaque in a more complex way, increasing whitlockite and apatite levels.” – by Darlene Dobkowski
Disclosures: The authors report no relevant financial disclosures.