Identifying immune system changes in teens can help predict CVD risk in adulthood

Obesity-related immune system changes in adolescents, particularly black teens, were linked to a greater risk for the development of CVD in adulthood, according to study results presented at the American Heart Association’s Council on Hypertension Scientific Sessions.

“Monitoring differences in the circulatory immune profile by blood tests could be used to recognize at an earlier stage — adolescence, for instance — those individuals [who] are at risk of developing CVD in the future, and this could allow for preventive therapies that would reduce such risk,” Carmen De Miguel, PhD, a postdoctoral scholar at the University of Alabama at Birmingham, told Cardiology Today.

Carmen De Miguel

By analyzing the circulating immune cell phenotypes and activation status through fluorescence-activated cell sorting and determining the total whole blood cell counts, researchers compared T-cell levels and the activation status of lean vs. obese teens to determine the effect of obesity on inflammation. The researchers compared 100 white and black lean (BMI < 60th percentile) and obese (BMI ≥ 95th percentile) public school students in Augusta, Georgia, aged 14 to 20 years.

White teens displayed less systemic inflammation, marked by reduced numbers of T cells in the blood, in response to obesity (lean vs. obese: CD3+ cells, 29.4 ± 8.14% vs. 25.58 ± 7.53%, P = .007; CD4+ cells, 28.51 ± 7.29% vs. 25.95 ± 6.04%, P = .049; CD8+ cells, 5.12 ± 2.6% vs. 4.04 ± 1.64%, P = .013). This finding was similar in white teens regardless of sex.

Black teen boys had significantly decreased circulating CD8+ and activated CD8+ cells (lean vs. obese: 5.16 ± 2.45% vs. 5.51 ± 2.27% and 0.53 ± 0.49% vs. 60 ± 0.55%); however, this was not observed in black teen girls. According to the researchers, this finding may indicate that “activation of CD8+ cells may be important in the increased prevalence of cardiovascular disease in female African Americans,” they wrote in the abstract.

Researchers also found that white blood cell counts were increased in obese vs. lean teens (6.67 ± 2.16 x 103/mm³ vs. 5.67 ± 1.62 x 103/mm³). When results were normalized to those white blood cell counts, obesity was associated with significantly higher values of CD3+ and CD4+ cells, independent of sex and race.

In other results, the data highlighted a positive correlation between HDL and circulating CD4+ cell percentage in obese white teens and a negative correlation between HDL and activated T cells in obese black boys.

Because symptoms of CVD generally appear years before the disease, awareness of these changes may lead to early diagnosis and prevention of at-risk patients with CVD. De Miguel recommended that health professionals use blood tests taken during teen years to identify those at risk.

“This could allow for preventive therapies and help changing exercise and diet habits to make the teen less prone to heart disease in adulthood,” De Miguel said. – by Trish Shea, MA

Reference:

De Miguel C, et al. Abstract P619. Presented at: American Heart Association’s Council in Hypertension Scientific Sessions; Sept. 16-19, 2015; Washington, D.C.

Disclosure: De Miguel reports no relevant financial disclosures.