Functional aortic stiffness: role of CD4(+) T lymphocytes

Association of T-cell receptor repertoires and arterial stiffness in patients with essential hypertension

BACKGROUND

Abnormal immune responses, particularly T-cell activity, are linked to vascular complications in hypertension, but mechanisms remain unknown. Our study aims to explore the association between arterial stiffness, assessed by brachial-ankle pulse wave velocity (baPWV), and T-cell receptor (TCR) repertoires in essential hypertension patients, focusing on understanding the role of T cells in the development of arterial stiffness in this population.

METHODS

The study included 301 essential hypertension patients and 48 age-matched normotensive controls. Essential hypertension patients were stratified into high (baPWV ≥1400 cm/s, n = 213) and low (baPWV <1400 cm/s, n = 88) baPWV groups. High-throughput sequencing analyzed peripheral TCRβ repertoires.

RESULTS

Significant TCRβ repertoire differences were observed between essential hypertension and normotensive groups, as well as between high and low baPWV essential hypertension subgroups. Specifically, patients in the high baPWV group exhibited notable variations in the utilization of specific TCR beta joining (TRBJ) and variable (TRBV) genes compared to the low baPWV group. These alterations were accompanied by reduced TCRβ diversity (represented by diversity 50 s), increased percentages of the largest TCRβ clones, and a higher number of TCRβ clones exceeding 0.1%. The presence of specific TCRβ clones was detected in both groups. Furthermore, reduced diversity 50s and elevated percentages of the largest TCRβ clones were independently correlated with baPWV, emerging as potential risk factors for increased baPWV in essential hypertension patients.

CONCLUSION

TCR repertoires were independently associated with arterial stiffness in patients with essential hypertension, implicating a potential role for dysregulated T-cell responses in the pathogenesis of arterial stiffness in this patient population.Trial registration: ChiCTR2100054414.

Vascular dysfunction and body mass index in African adults with HIV

BACKGROUND

Impaired vascular compliance is common among persons with HIV (PWH) and a risk factor for cardiovascular disease (CVD), though many studies documenting this are from regions with a high prevalence of overweight and obesity. The prevalence and characteristics of impaired vascular compliance among PWH with low body mass index (BMI) is not well described, particularly in sub-Saharan Africa (SSA) where the majority of PWH live, a low BMI is more common, and the burden of CVD is rising.

AIM

To assess non-invasive vascular compliance measurements, including augmentation index (AIX), pulse wave velocity (PWV) and pulse waveforms, in underweight, normal weight, and overweight PWH on long-term antiretroviral therapy (ART) in SSA.

METHODS

A cross-sectional study among PWH on ART at the University Teaching Hospital in Lusaka, Zambia. All participants had been on a regimen of efavirenz, emtricitabine, and tenofovir disoproxil fumarate for five or more years. Carotid-femoral PWV (cfPWV), carotid-radial PWV (crPWV), and the corresponding augmentation indexes (cfAIX and crAIX), were measured in all participants, in addition to aortic pressure waveforms, classified as type A, B, C and D according to reflected wave timings and amplitude. Multiple linear regression assessed relationships between demographic and clinical factors with vascular measurement endpoints.

RESULTS

Ninety one PWH on long-term ART were enrolled; 38 (42%) were underweight (BMI < 18.5 kg/m²), 43 (47%) were normal weight (18.5-24.9 kg/m²) and 10 (11%) were overweight (> 25 kg/m²). Median age was 41, 40 and 40 years, among the three groups, respectively, and the proportion of women increased with BMI level. Overweight participants had a 39% higher cfAIX compared to normal-weight participants, while being underweight was associated with 27% lower cfAIX, after adjusting for age, sex and blood pressure (P = 0.02 and P = 0.01, respectively), but measurements of cfPWV, crPWV and crAIX did not differ.

CONCLUSION

Underweight PWH in SSA had lower cfAIX measurements compared to normal weight individuals, indicating less arterial stiffness. However, similar cfPWV, crPWV and crAIX values among the underweight and overweight PWH suggest a low BMI may not confer substantial protection against impaired vascular compliance as a contributor to CVD risk among individuals on ART.

The relationship between brachial-ankle pulse wave velocity and peripheral blood lymphocyte subsets in hypertensives: a cross-sectional study

Arteriosclerosis is the common pathological basis of hypertension-related target organ damage, and pulse wave velocity (PWV) is commonly used to assess the degree of arterial stiffness. Previous studies have reported the correlation between peripheral blood inflammatory indicators and PWV in hypertensives, but few studies examined the role of immune cells in arteriosclerosis in the context of human hypertension. In order to enrich the understanding of this topic, we conducted a cross-sectional study on hospitalized hypertensives in Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology from January 2015 to February 2017 to investigate the relationship between brachial-ankle pulse wave velocity (baPWV) and peripheral blood lymphocyte subsets. Sixty-four eligible patients were enrolled in our study. The patients' blood pressure, height, body weight, and baPWV were collected, along with the lab results of their peripheral complete blood count, blood chemistry, and lymphocyte subsets. We studied the Spearman correlation between baPWV and lymphocyte subsets and other variables. We further used multivariable stepwise linear regression analysis and the results showed that baPWV was significantly correlated with age, height, systolic blood pressure, and the level of T lymphocytes (CD3⁺CD45⁺) in hypertensive patients (β = 8.77, P = 0.006; β = -17.50, P = 0.001; β = 6.70, P = 0.002, and β = -7.093, P = 0.024, respectively). According to our findings, baPWV was independently and negatively correlated with the level of peripheral blood T lymphocytes in hypertensives, and infiltration of T lymphocytes into the vessels wall may be a key part of the immune mechanism of arteriosclerosis in hypertension.