Increased aortic stiffness in adults with chronic indeterminate Chagas disease

The relationship between Brucella infection and aortic stiffness in children

OBJECTIVE

In this study, it was aimed to show whether Brucella infection, which causes various cardiovascular complications in children, can lead to an increase in aortic stiffness with a noninvasive method, echocardiography.

METHODS

Children who were diagnosed with Brucella infection and who had tachycardia, chest pain and murmur that were not related to body temperature increase during the treatment were evaluated cardiologically and had echocardiographic examination, were included in the study. Aortic strain, aortic distensibility measurement results and aortic stiffness index of the patients in the patient and control groups were calculated.

RESULTS

Our study included 53 cases with a mean age of 11.43±4.13 years in the patient group and 68 cases with a mean age of 10.16±3.61 years in the control group. We found that systolic blood pressure was lower in the patient group than in the control group (p=0.014). In the analysis of laboratory parameters, blood glucose level was found to be significantly higher in the patient group (p=0.001). In the statistical evaluation of aortic strain, aortic stiffness index and aortic distensibility measurement results between the patient and control groups, no statistically significant difference was found between the groups (p=0.287, p=0.784, p=0.208).

CONCLUSION

In our study, where we tried to show a new parameter that could contribute to the increase in aortic stiffness, the results showed that Brucella infection was not a factor that increased aortic stiffness in the pediatric age group.

Trypanosoma cruzi Infection Promotes Vascular Remodeling and Coexpression of α-Smooth Muscle Actin and Macrophage Markers in Cells of the Aorta

Chagas disease is an emerging global health problem; however, it remains neglected. Increased aortic stiffness (IAS), a predictor of cardiovascular events, has recently been reported in asymptomatic chronic Chagas patients. After vascular injury, smooth muscle cells (SMCs) can undergo alterations associated with phenotypic switch and transdifferentiation, promoting vascular remodeling and IAS. By studying different mouse aortic segments, we tested the hypothesis that Trypanosoma cruzi infection promotes vascular remodeling. Interestingly, the thoracic aorta was the most affected by the infection. Decreased expression of SMC markers and increased expression of proliferative markers were observed in the arteries of acutely infected mice. In acutely and chronically infected mice, we observed cells coexpressing SMC and macrophage (Mo) markers in the media and adventitia layers of the aorta, indicating that T. cruzi might induce cellular processes associated with SMC transdifferentiation into Mo-like cells or vice versa. In the adventitia, the Mo cell functional polarization was associated with an M2-like CD206+arginase-1+ phenotype despite the T. cruzi presence in the tissue. Only Mo-like cells in inflammatory foci were CD206+iNOS+. In addition to the disorganization of elastic fibers, we found thickening of the aortic layers during the acute and chronic phases of the disease. Our findings indicate that T. cruzi infection induces a vascular remodeling with SMC dedifferentiation and increased cell populations coexpressing α-SMA and Mo markers that could be associated with IAS promotion. These data highlight the importance of studying large vessel homeostasis in Chagas disease.

Subject-Specific Pressure Normalization of Local Pulse Wave Velocity: Separating Intrinsic From Acute Load-Dependent Stiffening in Hypertensive Patients

Pulse wave velocity (PWV) is a powerful predictor of cardiovascular events. However, its intrinsic blood pressure (BP)-dependency complicates distinguishing between acute and chronic effects of increased BP on arterial stiffness. Based on the assumption that arteries exhibit a nearly exponential pressure-area (P-A) relationship, this study proposes a method to assess intersubject differences in local PWV independently from BP. The method was then used to analyze differences in local carotid PWV (cPWV) between hypertensive and healthy normotensive people before and after BP-normalization. Pressure (P) and diameter (D) waveforms were simultaneously acquired via tonometer at the left and ultrasound scanning at right common carotid artery (CCA), respectively, in 22 patients with Grade 1 or 2 hypertension and 22 age- and sex-matched controls. cPWV was determined using the D²P-loop method. Then, the exponential modeling of the P-area (A = πD²/4) relationships allowed defining a mathematical formulation to compute subject-specific changes in cPWV associated with BP changes, thus enabling the normalization of cPWV against intersubject differences in BP at the time of measurement. Carotid systolic BP (SBP) and diastolic BP (DBP) were, on average, 17.7 (p < 0.001) and 8.9 mmHg (p < 0.01) higher in hypertensives than controls, respectively. cPWV was 5.56 ± 0.86 m/s in controls and 6.24 ± 1.22 m/s in hypertensives. BP alone accounted for 68% of the cPWV difference between the two groups: 5.80 ± 0.84 vs. 6.03 ± 1.07 m/s after BP-normalization (p = 0.47). The mechanistic normalization of cPWV was in agreement with that estimated by analysis of covariance (ANCOVA). In conclusion, the proposed method, which could be easily implemented in the clinical setting, allows to assess the intersubject differences in PWV independently of BP. Our results suggested that mild hypertension in middle-aged subjects without target organ damage does not significantly alter the stiffness of the CCA wall independently of acute differences in BP. The results warrant further clinical investigations to establish the potential clinical utility of the method.