Mirosława Urban

New atherosclerosis risk factors in obese, hypertensive and diabetic children and adolescents

UNLABELLED In the last few years it has been proved that risk factors for atherosclerosis are present in children and adolescents, and that already at this early age they are connected with anatomic, atheromatous changes in vessels. These changes can not be fully explained as occurring in young people exhibiting traditional risk factors for the disease. The aim of the study was to evaluate levels of several new atherosclerosis risk factors (lipoprotein (a) (Lp(a)), apolipoprotein A-I (Apo A-I), apolipoprotein B (Apo B), homocysteine (Hcy), fibrinogen (FB), tissue plasminogen activator (t-PA) and tissue plasminogen activator inhibitor type 1 (PAI-1)) in children and adolescents with traditional risk factors (obesity, hypertension, diabetes). MATERIALS AND METHODS The study group consisted of 285 children and adolescents aged 14.3 years. Children were divided according to their main disease into groups: group A, children with obesity (n=49); group B, children with obesity and coexisting hypertension (n=56); group C, children with hypertension (n=58) and group D, children with diabetes (n=122). Control group consisted of 79 healthy children and adolescents aged 14.1 years. Lp(a), Apo A-I and Apo B levels were estimated by use of immunoturbidimetric methods; total Hcy, FB, t-PA and PAI-1 were estimated by use of immunoenzymatic methods. RESULTS Lp(a) level in the total study group was 30 mg/dl and was over twice higher than in control group, 14 mg/dl. Apo A-I level was significantly lower in group A (127.6 mg/dl) and in group B (125.8 mg/dl) versus 135.6 mg/dl in controls. The level of Apo B was significantly higher in total study group (86.2 mg/dl) and in groups A, B and D versus 73.5 mg/dl in controls. Hcy was higher in group B (8 micromol/l) and in group C (9.4 micromol/l) versus 6.2 micromol/l in the control group. The FB level was higher in the total study group (276.7 mg/dl) and in groups A (318.8 mg/dl) and B (322.6 mg/dl) versus 252.8 mg/dl in controls. Significantly higher t-PA level was found in groups A (9 ng/ml) and B (9.7 ng/ml) versus 7.3 ng/ml in controls, and PAI-1 level was significantly higher in the total study group (62.3 ng/ml) and in groups A (73.8 ng/ml), B (78 ng/ml) and C (73 ng/ml) versus 42.4 ng/ml in the control group. Correlation analysis showed significant relationship between body mass index (BMI) and Apo B, Hcy, FB, t-PA and PAI-1. Blood pressure values correlated positively with Hcy. Correlations were verified in multiple regression analysis models: FB and t-PA levels depended on BMI, and Hcy depended on systolic blood pressure. CONCLUSIONS (1) Young obese, hypertensive and diabetic patients present significant disturbances in lipid metabolism, regarding mainly total cholesterol, LDL, triglycerides, as well as Lp(a), Apo A-I and Apo B levels. Unfavourable lipid profile is characteristic mainly for children with obesity and accompanying hypertension. (2) Elevated Hcy levels are found in children with hypertension. (3) Elevated FB level and diminished fibrinolytic activity are characteristic of obese children.

Relationship between endothelial dysfunction, carotid artery intima media thickness and circulating markers of vascular inflammation in obese hypertensive children and adolescents.

BACKGROUND Adhesion molecules released by dysfunctional endothelium are considered as markers of vascular inflammation in early atherosclerosis. Non-invasive ultrasound methods are now available to detect first preclinical signs of the disease. AIM To investigate the relationship between selected adhesion molecules and ultrasound indicators of early atherosclerosis: endothelial function measured by flow-mediated dilatation (FMD) and intima media thickness (IMT). PATIENTS The study group consisted of 85 children, mean age 14.6 years, of whom 22 were obese, 31 were hypertensive, and 32 obese and hypertensive. The control group included 26 healthy children. METHODS Adhesin concentrations were determined by ELISA. FMD and IMT were evaluated by ultrasound. RESULTS A positive correlation was found between sICAM-1 (soluble intercellular adhesion molecule 1) and IMT (r = 0.32, p = 0.013, 95% CI: 0.11 to 0.49) and a negative correlation between IMT and FMD (r = -0.26, p = 0.04, 95% CI: -0.43 to -0.04) in the whole study group. In the particular groups, we found significant correlations only in obese hypertensive children. sICAM-1 correlated positively with IMT (r = 0.52, p = 0.001, 95% CI: 0.2 to 0.72) and negatively with FMD (r = -0.31, p = 0.027, 95% CI: -0.6 to -0.2). sE-selectin correlated positively with IMT (r = 0.41, p = 0.012). In regression models, IMT correlated with sICAM-1 (beta = 0.37, p = 0.03) and body mass index (beta = 0.55, p = 0.02), and FMD correlated negatively with sICAM-1 (beta = -0.47, p = 0.04). CONCLUSIONS The association between inflammatory markers of the endothelium with impaired vasodilatation activity and the first atherosclerotic structural changes in the common carotid arteries were found in obese hypertensive children and adolescents. The coexistence of obesity and hypertension predisposes these young patients to closely related disturbances connected with early atherosclerosis.

The association of early atherosclerosis and retinopathy in adolescents with type 1 diabetes: preliminary report

Recent studies have shown a close correlation between advanced diabetic retinopathy and the late stages of atherosclerosis. The purpose of this study was to analyse the association between diabetic retinopathy and early atherosclerotic changes in adolescents with type 1 diabetes. We studied 28 adolescents with type 1 diabetes. Eight patients with nonproliferative retinopathy were compared with the remaining 20 patients, and with 11 healthy controls. The function of endothelium was assessed by measuring flow-mediated dilatation (FMD), the intima-media thickness (IMT) of the common carotid arteries and adhesion molecules (sICAM-1, sVCAM-1, sE-selectin). In the group with retinopathy FMD equalled 7.8±4.1% vs. 12.1±5.1% in the control group (p=0.04), and in the group without retinopathy, 7.6±5.5% (p=0.04 compared to controls). Higher IMT was found in all patients with diabetes in comparison with healthy controls: 0.49±0.06 mm vs. 0.42±0.03 mm (p=0.001). Patients with retinopathy had a significantly higher value of IMT in comparison not only with controls but also with patients without complications: 0.56±0.06 mm vs. 0.47±0.03 mm (p=0.0001). Adhesion molecule levels were not changed in patients with retinopathy. Higher IMT was found in adolescents with diabetic retinopathy in comparison with patients without complications, which may suggest that macrovascular changes are more advanced in these patients than in their diabetic peers without retinopathy.

Relationship between CTLA-4 and CD28 molecule expression on T lymphocytes and stimulating and blocking autoantibodies to the TSH-receptor in children with Graves' disease.

The present study was performed to elucidate the relationship between CTLA-4/CD28 molecules and stimulating (TSAb) and blocking (TBAb) antibodies to the TSH-receptor (TSH-R) in Graves’ disease. CD28 and CD152 (CTLA-4) are glycoprotein molecules which provide a potent costimulatory signal for T-cell activation and proliferation via interactions with their ligands, B7.1/B7.2 molecules, which are present on the surface of antigen-presenting cells. The aim of the study was to estimate the expression of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4, CD152), CD28, B7.1 (CD80), and B7.2 (CD86) molecules on peripheral blood cells in patients with Graves’ disease (GD) (n = 55, mean age 15.5 ± 5.1 years) and nontoxic nodular goiter (NTNG) (n = 55, mean age 15.2 ± 4.5 years), in comparison with sex and age-matched healthy control subjects (n = 55, mean age 15.2 ± 3.9 years). The expression of the costimulatory molecules on mononuclear cells was analyzed by three-color flow cytometry using a Coulter EPICS XL cytometer. Detection of TSAb and TBAb to the TSH-R using JPO9 CHO cells in unfractionated serum was measured by a highly sensitive commercial radioimmunoassay. When compared with healthy control subjects and euthyroid patients with GD, untreated patients with GD showed a significant increase of CD152+ (p < 0.001, p < 0.001) and CD28+ (p < 0.01, NS) T lymphocytes, respectively. After 6–12 months of methimazole therapy, the percentage of these cells in the peripheral blood of hyperthyroid patients returned to normal values. In addition, patients with GD showed an increase in the percentage of both B7.1 (3.8%) and B7.2 (18.4%) molecules on activated monocytes, compared to patients with NTNG (0.5% p < 0.05, 2.5% p < 0.01, respectively) and healthy control subjects (0.2% p < 0.05, 0.8% p < 0.003, respectively). In patients with untreated GD there was a statistically significant positive correlation between the expression of CTLA-4 on the surface of peripheral blood T cells and the index of TSAb antibodies (R = 0.54, p < 0.001) as well as a negative correlation with TBAb antibody titer (R = –0.58, p < 0.001). However, no such correlations were noted with regard to CD28 and anti-TPO, anti-TG, and TRAb antibodies. We conclude that changes in the expression of costimulatory molecules on the surface of peripheral blood T cells and their significant relationship with the level of antithyroid antibodies indicate an involvement of these molecules in the pathogenesis of GD.

Expression of Bcl-2 Family Proteins in Thyrocytes from Young Patients with Immune and Nonimmune Thyroid Diseases

The Bcl-2 family proteins that control homeostasis of cells play an important role in apoptosis. This group consists of antiapoptotic (Bcl-2, Bcl-XL) and proapoptotic (Bcl-2 associated protein X, Bax; B-cell homologous antagonist/killer, Bak) molecules. In the thyroid, abnormal apoptotic activity may be involved in a variety of diseases such as autoimmune thyroid diseases. The aim of the current study was to estimate the expression of pro- and antiapoptotic proteins in thyroid tissues from young patients with Graves’ disease (GD), nontoxic nodular goiter and toxic nodular goiter using Western Blot and immunohistochemistry. Identification of the antiapoptotic Bcl-2 and Bcl-XL molecules in the thyrocytes revealed higher expression of both proteins in patients with GD (assessed as +++/++ and ++/+, respectively). In adolescents with toxic and nontoxic nodular goiter, this expression was lower (Bcl-2 ++/+ , ++/+; Bcl-XL +, +). The tissue material was additionally subjected to Western Blot analysis, which in GD patients showed the presence of Bcl-2 and Bcl-XL in one band p26 kDa. In patients with toxic and nontoxic nodular goiter, the intensity of expression for these two antiapoptotic proteins was lower (referred to band 26 kDa for Bcl-2 and Bcl-XL). Identification of the proapoptotic proteins Bax and Bak revealed their predominance in thyrocytes of GD patients (+, ++/+, respectively) as compared to patients with toxic and nontoxic nodular goiter (0/+, 0/+ for Bax and 0/+, 0/+ for Bak). In GD patients, Western Blot analysis showed Bax expression in one band 21 kDa and Bak in two bands p50, p24 kDa. In patients with nodular goiter, the degree of expression of both proapoptotic proteins was lower and referred to band 21 kDa for Bax (toxic and nontoxic goiter) and 24 kDa for Bak (toxic goiter only). Patients with GD showed a statistically significant correlation between Bcl-2 expression and antibodies against receptor for thyroid stimulating hormone (R = 0.47, p < 0.03); however, such a correlation was not observed in patients with nodular goiter. In conclusion, our findings suggest that the changes in the expression of regulatory proteins of the Bcl-2 family in the thyroid follicular cells indicate the involvement of apoptosis in the pathogenesis of GD.

Heart rate turbulence in children--age and heart rate relationships.

Heart rate turbulence (HRT) is a chronotropic response of the sinus heart rhythm to ventricular premature beat (VPB). Children show decreasing heart rate together with the maturation of the autonomic nervous system. The aim of the research was to assess the relationship between HRT parameters, age, and heart rate and time domain heart rate variability (HRV) parameters in healthy children. Twenty-four-hour ECG Holter recording was performed on 398 healthy children. The mean RR interval preceding VPB, number of VPBs, and HRT parameters—turbulence onset (TO) and turbulence slope (TS)—were determined. We observed significant correlation among TS and mean RR and age. Children with prepubertal status have lower values of TS compared with those during puberty. According to given quartiles, upper for TO was ≥–0.8%, lower for TS was ≤4.56 ms/RR, 13 patients (3%) obtained abnormal both TO and TS. The correlations between HRT and HRV parameters were observed among the youngest children. Age and heart rate preceding VPB have no effect on HRT onset in children, whereas HRT slope is highly dependent on these variables. Our results support hypothesis that in older children HRT is dependent on autonomic tone and also determined by other intrinsic modulators.

Percentage of LFA-1+ and ICAM-1+ peripheral blood mononuclear cells in children and adolescents with type 1 diabetes does not distinguish patients with vascular complications.

There are only few studies evaluating lymphocytes activation in the diabetic vascular complications. ICAM-1/LFA-1 adhesion molecules not only participate in the lymphocyte T proliferation but also mediate leukocyte migration to the site of inflammation. We assess a relationship between the percentage of ICAM-1 and LFA-1 expressing PBMCs and the evolution of vascular complications in T1D in children and adolescents. The study was carried out on 60 children and adolescents with T1D (aged 9-20): (a) T1D lasting <5 years (n=20), (b) T1D lasting >5 years (n=20), without complications c) T1D lasting >5 years complicated with microalbuminuria, arterial hypertension, diabetic retinopathy (20 n). 20 healthy volunteers, age and sex matched constituted the control group. The expression of adhesion molecules was evaluated by using three-color flow cytometry. In children and adolescents with T1D <5 years, the percentage of ICAM-1+ and LFA-1+ PBMCs was decreased vs. controls (p<0.05 and p<0.001, respectively). Both in patients with T1D>5 years without vascular complications and in T1D with vascular disease the percentage of LFA-1+ T lymphocytes was significantly reduced in the peripheral blood (p<0.001 vs. healthy controls). In conclusion the percentage of LFA-1+ and ICAM-1+ PBMCs does not distinguish patients with vascular complications however decreased percentage of LFA-1+ PMBCs could serve as a nonspecific marker of the development of local inflammatory process in Type 1 diabetes.