Obesity is a disease in which long-term energy intake exceeds consumption, resulting in excessive energy stored in the form of fat and increased risk of diseases in various systems of the body [
Previous studies have reported that the levels of reactive oxygen species (ROS), C-reactive protein (CRP), and proinflammatory cytokines were significantly increased when endothelial dysfunction occurs, which led to the enhanced expression and secretion of some adhesion molecules, such as intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), and E-, L-, and P-selections, and consequently promoting the concentration of blood and the formation of small patches [
Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a widely investigated long noncoding RNA (lncRNA) and has been reported to be related with endothelial function [
In this study, the expression levels of MALTA1 and miR-320a in obese children and adolescents before and after exercise were examined, and their correlation with endothelial dysfunction was investigated by evaluating the levels of VCAM-1, ICAM-1, and E-selectin. The findings of this study may uncover the relationship between the MALAT1/miR-320a axis and the improved endothelial function induced by exercise.
This study retrospectively analyzed the data from 60 obese children and adolescents (age range of 8–16 years) who were admitted to Weifang People’s Hospital between May 2019 and August 2019. The following were inclusion criteria: (i) the body mass indexes (BMI) of the study objects were ≥23.9 kg/m2; (ii) none of the cases had cardiovascular diseases, kidney diseases, or chronic inflammation diseases; (iii) had no history of smoking and drinking; (iv) had no hormone medicine during the recent 6 months; and (v) had no physical activity restrictions or regular exercise habits. In addition, the cases with chronic diseases, endocrine diseases, dyskinesia, taking medications, smoking, allergies, thyroid diseases, cardiovascular diseases, and consumption of any supplement or oral antibiotics in previous 3 months were excluded. Only the data from children and adolescents who were in accord with the above criteria were collected and analyzed in this study. All the analyzed children and adolescents had BMI values more than or equal to the 95th percentile. Informed consent was obtained from the parents of the participants, and the study procedures were approved by the Ethics Committee of Weifang People’s Hospital.
Among the 60 obese children and adolescents, 40 cases (exercise group) were subjected to 12 weeks of diet control and exercise training and 20 cases (matched group) received diet control for 12 weeks, but still remained their previous life habits. For the diet control, all obese children and adolescents were required to appropriately reduce the intake of high-calorie and high-fat foods and increase the intake of vegetables and fruits. The carbohydrate ratio accounted for 40–50%, protein accounted for 20–30%, and fat accounted for 20–25%, and the intake of vitamins, trace elements, inorganic salts, and water was ensured. The energy intake was calculated based on the previously reported criteria [
The value and BMI and circumferences of the neck, waist, and hip were measured and recorded before and after the 8-week of exercise training by the same individuals [
After a 12-hour overnight fast, blood samples were collected from the participants before and after the intervention. Serum was isolated from the blood samples by centrifugation and stored at −20°C for further analyses. Total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), and fasting insulin (FIN) were measured using an automatic biochemical analyzer (HITACHI 7600, Japan). The homeostasis model of assessment of insulin resistance (HOMA-IR) was calculated.
The levels of endothelial dysfunction markers in serum samples, including VCAM-1 (Cat.
Total RNA was extracted from serum samples using TRIzol reagent (Invitrogen, Carlsbad, CA, USA). cDNA was synthesized from RNA using a PrimeScript RT reagent kit (TaKaRa, Shiga, Japan) following the manufacturer’s instruction. The relative expression of MALAT1 and miR-320a was measured using qPCR with SYBR green I Master Mix kit (Invitrogen, Carlsbad, CA, USA) on a 7500 Real-Time PCR System (Applied Biosystems, USA). GAPDH and U6 were used as internal controls for MALAT1 and miR-320a, respectively. The method of 2−ΔΔCt was used to calculate the final expression values.
SPSS 26.0 (SPSS Inc., Chicago, IL) and GraphPad 7.0 were (GraphPad Software, Inc., USA) were used to analyze the data of this study. The data were expressed as mean ± SD, and differences were compared using Student’s
The anthropometric data and blood data of the obese children and adolescents before and after the dietary and/or exercise intervention are given in Table
Comparisons of the baseline characteristics of obese children and adolescents before and after intervention.
Characteristics | Matched group ( | Exercise group ( | ||
---|---|---|---|---|
Before | After | Before | After | |
Age (years) | 12.05 ± 2.28 | 12.05 ± 2.28 | 12.30 ± 2.61ns | 12.30 ± 2.61 |
Gender (males/females) | 13/7 | 13/7 | 28/12ns | 28/12 |
BMI (kg/m2) | 29.33 ± 1.11 | 28.63 ± 0.94 | 29.33 ± 1.29ns | 26.09 ± 1.05 |
Neck circumference (cm) | 39.30 ± 3.99 | 39.10 ± 2.49 | 40.50 ± 4.16ns | 36.80 ± 2.71 |
Waist circumference (cm) | 93.00 ± 2.24 | 87.50 ± 1.90 | 92.20 ± 2.65ns | 78.10 ± 2.85 |
Hip circumference (cm) | 99.40 ± 2.67 | 96.20 ± 2.86 | 99.60 ± 2.55ns | 90.80 ± 2.88 |
TC (mM) | 4.86 ± 0.26 | 4.06 ± 0.17 | 4.82 ± 0.19ns | 3.44 ± 0.16 |
TG (mM) | 1.73 ± 0.27 | 0.90 ± 0.08 | 1.79 ± 0.22ns | 0.77 ± 0.06 |
LDL-C (mg/dL) | 91.77 ± 13.90 | 89.85 ± 13.76 | 92.64 ± 14.30ns | 85.08 ± 13.60 |
HDL-C (mg/dL) | 46.44 ± 9.04 | 49.72 ± 8.30 | 48.78 ± 9.58ns | 51.12 ± 5.70 |
HOMA-IR | 3.17 ± 1.55 | 3.01 ± 1.42 | 3.34 ± 1.63ns | 2.51 ± 0.97 |
BMI, body mass index; TC, total cholesterol; TG, triglyceride; LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment-insulin resistance; ns, no significance when compared to the data before intervention in the matched group.
The levels of endothelial dysfunction markers, including VCAM-1, ICAM-1, and E-selectin, were measured using ELISA assay, and the results shown in Table
Endothelial dysfunction markers in obese children and adolescents before and after intervention.
Indicators | Matched group ( | Exercise group ( | ||
---|---|---|---|---|
Before | After | Before | After | |
VCAM-1 (ng/mL) | 793.23 ± 19.16 | 782.21 ± 24.97 | 792.96 ± 36.00ns | 770.88 ± 36.13 |
ICAM-1 (ng/mL) | 245.91 ± 14.92 | 239.00 ± 15.15 | 242.30 ± 17.53ns | 218.58 ± 12.92 |
E-selectin (ng/mL) | 169.90 ± 77.77 | 143.76 ± 54.20 | 171.05 ± 60.59ns | 101.40 ± 37.54 |
VCAM-1, vascular cell adhesion molecule 1; ICAM-1, intercellular adhesion molecule 1; ns, no significance when compared to the data before intervention in the matched group.
The expression of MALAT1 and miR-320a measured by RT-qPCR is shown in Figure
Relative expression of MALAT1 and miR-320a in obese children and adolescents before and after intervention. (a) There was no difference in MALAT1 expression between the matched group and the exercise group, but 12-week exercise training in the exercise group significantly reduced the expression of MALAT1 compared to the matched group receiving only dietary control. (b) After exercise training, the expression of MALAT1 was decreased in obese children and adolescents. (c) There was no difference in miR-320a expression between the matched group and the exercise group, but 12-week exercise training in the exercise group significantly increased the expression of miR-320a compared to the matched group receiving only dietary control. (d) After the exercise training, the expression of miR-320a was elevated in obese children and adolescents. ns, no significance;
Correlations of MALAT1/miR-320a axis with the anthropometric features and blood indices after exercise were evaluated by the Pearson correlation method. The data listed in Table
Correlation of the MALAT1/miR-320a axis with the baseline features of obese children and adolescents after exercise.
Characteristics | MALAT1 expression | miR-320a expression | ||
---|---|---|---|---|
Age | 0.001 | 0.982 | −0.008 | 0.962 |
Gender | 0.090 | 0.579 | −0.027 | 0.867 |
BMI | 0.325 | 0.031 | −0.361 | 0.029 |
Neck circumference | 0.092 | 0.171 | −0.175 | 0.280 |
Waist circumference | 0.213 | 0.043 | −0.226 | 0.041 |
Hip circumference | 0.289 | 0.038 | −0.267 | 0.040 |
TC | 0.452 | 0.012 | −0.501 | 0.008 |
TG | 0.121 | 0.246 | −0.128 | 0.330 |
LDL-C | 0.512 | 0.008 | −0.499 | 0.010 |
HDL-C | −0.188 | 0.231 | 0.143 | 0.379 |
HOMA-IR | 0.446 | 0.025 | −0.431 | 0.028 |
BMI, body mass index; TC, total cholesterol; TG, triglyceride; LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostatic model assessment-insulin resistance.
To evaluate the correlation between changes in MALAT1/miR-320a axis and endothelial dysfunction after exercise in obese children and adolescents, the correlations of MALAT1 and miR-320a with VCAM-1, ICAM-1, and E-selectin levels were assessed. As shown in Figure
Correlation of MALAT1 and miR-320a levels with the levels of endothelial dysfunction markers. (a)–(c). The expression of MALAT1 was positively correlated with the levels of VCAM-1, ICAM-1, and E-selectin (all
The beneficial effects of exercise have been reported in various human diseases, especially in cardiovascular disorders [
Despite, it is well known that exercise can improve physical health, and the underlying mechanisms of exercise remain unclear. Emerging studies have emphasized the association of noncoding RNAs with exercise. For example, Liu et al. reported some lncRNAs that could be regulated by exercise training in insulin resistance-related vascular injury and proposed that the deregulated lncRNAs might be biomarkers to reflect vascular injury in high-fat diet-induced insulin resistance [
MALAT1 is a widely studied lncRNA, and its regulatory effects on cellular functions have been reported in different cell types [
miR-320a has been identified as a target of MALAT1 and participates in the regulation of endothelial function by MALAT1 [
Taken together, the data of this study confirmed the protective effects of exercise on endothelial dysfunction in obese children and adolescents and demonstrated that exercise training significantly reduces MALAT1 expression and increases miR-320a expression and that the MALAT1/miR-320a axis may be related with the alleviating effects of exercise on endothelial function in obese children and adolescents with obesity. The findings of this study further uncover the mechanisms underlying the beneficial effects of exercise on endothelial dysfunction, and the MALAT1/miR-320a axis may provide novel targets for the improvement of endothelial function in obese children and adolescents. This study have some limitations, which mainly include the limited sample size and the lack of verification using animal models. Further investigations are necessary to confirm the conclusion of this study using a larger study population. In addition, in vitro experiments using endothelial cells and obese animal models should be carried out to study the role of the MALAT1/miR-320a axis in the mechanisms of exercise.
The data used to support the findings of this study are available from the corresponding author upon request.
The experimental procedures were all in accordance with the guideline of the Ethics Committee of Weifang People’s Hospital.
Written informed consent for publication was obtained from each participant.
The authors declare that they have no conflicts of interest.
Wenkun Li and Qian Li contributed equally to this work. XZ analyzed and interpreted the data regarding. YY and HC performed the examination of cell. XZ and YW wrote and revised the manuscript. All authors read and approved the final manuscript.