Reproducibility of circulating endothelial cell enumeration and activation in children and adolescents

Relationship of Endothelial Microparticles to Obesity and Cardiovascular Disease Risk in Children and Adolescents

Background

Microparticles and endothelial microparticles (EMPs) are implicated in accelerating cardiovascular disease (CVD); however, data in pediatrics are limited. We examined the relationship of microparticles and EMPs with adiposity and subclinical CVD risk measures in a pediatric population to determine their potential as biomarkers of CVD risk.

Methods and Results

A cross‐sectional study of youth (n=280; ages 8–20 years) with a range of body mass index categories was used. Microparticles, EMPs, and activated EMPs were measured by flow cytometry. %Body fat and %visceral adipose tissue were measured by dual X‐ray absorptiometry. Measures of arterial stiffness and vascular wall structure were obtained. Linear regression (with log‐transformed outcomes) and logistic regression were used to evaluate associations and all results were exponentiated. Youth with overweight/obesity and severe obesity had 2.50 (95% CI, 1.56–4.01) and 3.42 (95% CI, 2.15–5.43) times the geometric means of the total number of microparticles, respectively, compared with those with normal weight. Youth with overweight/obesity and severe obesity had 1.97 (95% CI, 1.09–3.55) and 2.34 (95% CI, 1.31–4.19) times the geometric means of the total number of EMPs, respectively, compared with those with normal weight. There were positive associations between the levels of both microparticles and EMPs with higher adiposity measures and poor CVD risk measures. Youth with higher adiposity showed 1.84 times the odds of having high levels of activated EMPs (%) (odds ratio, 1.84; 95% CI, 1.08–3.14) compared with those with normal weight.

Conclusions

Levels of microparticles, EMPs, and activated EMPs were positively associated with adiposity and poor subclinical CVD risk in a pediatric population.

Relationship of Circulating Endothelial Cells With Obesity and Cardiometabolic Risk Factors in Children and Adolescents

Background Circulating endothelial cells (CECs) reflect early changes in endothelial health; however, the degree to which CEC number and activation is related to adiposity and cardiovascular risk factors in youth is not well described. Methods and Results Youth in this study (N=271; aged 8-20 years) were classified into normal weight (body mass index [BMI] percentage <85th; n=114), obesity (BMI percentage ≥95th to <120% of the 95th; n=63), and severe obesity (BMI percentage ≥120% of the 95th; n=94) catagories. CEC enumeration was determined using immunohistochemical examination of buffy coat smears and activated CEC (percentage of vascular cell adhesion molecule-1 expression) was assessed using immunofluorescent staining. Cardiovascular risk factors included measures of body composition, blood pressure, glucose, insulin, lipid profile, C-reactive protein, leptin, adiponectin, oxidized low-density lipoprotein cholesterol, carotid artery intima-media thickness, and pulse wave velocity. Linear regression models examined associations between CEC number and activation with BMI and cardiovascular risk factors. CEC number did not differ among BMI classes (P>0.05). Youth with severe obesity had a higher degree of CEC activation compared with normal weight youth (8.3%; 95% CI, 1.1-15.6 [P=0.024]). Higher CEC number was associated with greater body fat percentage (0.02 per percentage; 95% CI, 0.00-0.03 [P=0.020]) and systolic blood pressure percentile (0.01 per percentage; 95% CI, 0.00-0.01 [P=0.035]). Higher degree of CEC activation was associated with greater visceral adipose tissue (5.7% per kg; 95% CI, 0.4-10.9 [P=0.034]) and non-high-density lipoprotein cholesterol (0.11% per mg/dL; 95% CI, 0.01-0.21 [P=0.039]). Conclusions Methods of CEC quantification are associated with adiposity and cardiometabolic risk factors and may potentially reflect accelerated atherosclerosis as early as childhood.

Associations between paediatric fatigue and eating behaviours

BACKGROUND

In adults, poor sleep quality is associated with increased obesogenic eating behaviours; less is known about this relationship in youth. The objectives of this study were to assess the strength of association between fatigue-related quality of life (QoL) and eating behaviours among youth and to describe the associations in participants with percent body fat (%BF) above and below the 90th percentile for sex and age.

METHODS

Caregiver-reported measures of fatigue (Pediatric QoL Multidimensional Fatigue Scale) and eating behaviours (Child Eating Behaviour Questionnaire) were obtained from participants aged 8-17 years. %BF was measured by iDXA and grouped by sex- and age-specific percentiles. Multiple linear regression adjusting for age, sex and race/ethnicity was used.

RESULTS

Of the 352 participants (49% male), 44.6% had %BF >90th percentile. General, sleep/rest and cognitive fatigue QoL was inversely associated with food approach behaviours: food responsiveness, enjoyment of food, emotional overeating and desire to drink. For participants with %BF >90th percentile, higher general fatigue QoL was associated with higher satiety responsiveness (0.13; 95% confidence interval [CI 0.03, 0.24]). For participants with %BF ≤90th percentile, higher general fatigue QoL was associated with less satiety responsiveness (-0.16; 95% CI [-0.31, -0.01]).

CONCLUSION

Less fatigue symptoms were associated with less behaviours associated with food approach among paediatric participants. For participants with %BF >90th percentile, less symptoms of general fatigues corresponded with more satiety. Though causation has yet to be established, youth with elevated %BF should be screened for fatigue symptoms and offered counselling on sleep hygiene or a sleep medicine referral to help mitigate weight gain.

Reproducibility of endothelial microparticles in children and adolescents

Aim: We assessed reproducibility of endothelial microparticles (EMPs) enumeration among youth. Methods & results: Four microparticle (MP) indices - total MP per microliter platelet free plasma (PFP), total EMPs per microliter PFP, percent activated EMPs and percent lactadherin positive (LACT[+]) of total EMPs - were measured at two visits (baseline and 7 ± 3 days follow-up) to determine reproducibility overall and by obesity status. We examined CD31+ or CD144+ with CD41-EMP events of size 0.3-1.0 μm. No statistically significant differences were observed between visits for any of the four MP indices. The within-participant and between-participant coefficient of variation was acceptable (range: 1.13-2.37) with good intraclass-correlation coefficient for all indices except total MP per microliter (range: 0.10-1.00). Conclusion: Total EMPs per microliter PFP, percent-activated EMPs and percent LACT(+) of total EMPs are reproducible among youth.

Determination of Bilateral Symmetry of Carotid Artery Structure and Function in Children and Adolescents

We compared the symmetry of carotid arteries in youth with high-resolution ultrasound. Participants (n=230 (121 females),13.8 ± 2.9 years old) were assessed for: intima media thickness (cIMT), lumen diameter (cLD), incremental elastic modulus (cIEM), diameter compliance (cDC), cross-sectional compliance (cCSC), diameter distensibility (cDD), and cross-sectional distensibility (cCSD). No significant differences (P >0.05 all) were found for cIMT (0.49 ± 0.09 mm vs. 0.49 ± 0.08 mm), cIEM (1095 ± 382 mmHg vs. 1116 ± 346mmHg), cDC (0.01 ± 0.0 mm/mmHg vs. 0.01 ± 0.0 mm/mmHg), cCSC (0.01 ± 0.001/mmHg vs. 0.01 ± 0.001/mmHg), cDD (14.0 ± 3.16% vs. 13.7 ± 3.18%), and cCSD (30.1 ± 7.37% vs. 29.4 ± 7.36%). Significant differences were found for cLD (6.06 ± 0.62 mm vs. 6.33 ± 0.64 mm, P <0.001). These data suggest that these values may be used interchangeably if one side is inaccessible.