Ákos Baráth

Haplotype analysis of the apolipoprotein A5 gene in obese pediatric patients

OBJECTIVE Apolipoprotein A5 (APOA5) gene variants have been shown to be associated with elevated TG levels; the T-1131C (rs662799) variant has been reported to confer risk for the metabolic syndrome in adult populations. Little is known about the APOA5 variants in pediatric population, no such information is available for pediatric obesity at all. Here we examined four haplotype-tagging polymorphisms (T-1131C, IVS3 + G476A [rs2072560], T1259C [rs2266788] and C56G [rs3135506]) and studied also the frequency of major naturally occurring haplotypes of APOA5 in obese children. METHODS The polymorphisms were analyzed in 232 obese children, and in 137 healthy, normal weight controls, using PCR-RFLP methods. RESULTS In the pediatric patients we could confirm the already known adult subjects based association of -1131C, IVS3 + 476A and 1259C variants with elevated triglyceride concentrations, both in obese patients and in the controls. The prevalence of the APOA5*2 haplotype (containing the minor allele of T-1131C, IVS3 + G476A and T1259C SNPs together) was 15.5% in obese children, and 5.80% in the controls (p<0.001); multiple logistic regression analysis revealed that this haplotype confers susceptibility for development of obesity (OR=2.87; 95% CI: 1.29-6.37; p≤0.01). By contrast, the APOA5*4 haplotype (with -1131C alone) did not show similar associations. Our findings also suggest that the APOA5*5 haplotype (1259C alone) can be protective against obesity (OR=0.25; 95% CI: 0.07-0.80; p<0.05). CONCLUSIONS While previous studies in adults demonstrated, that the APOA5 -1131C minor allele confers risk for adult metabolic syndrome, here we show, that the susceptibility nature of this SNP restricted to the APOA5*2 haplotype in pediatric obese subjects.

Roles of Paraoxonase and Oxidative Stress in Adolescents with Uraemic, Essential or Obesity-Induced Hypertension

Background/Aims: Paraoxonase 1 (PON1) is associated with high-density lipoproteins in the plasma, and is capable of hydrolysing oxidized lipids and preventing the oxidation of low-density lipoproteins. Oxidative stress and the PON1 (activity and Q192R polymorphism) were analysed in adolescent patients with essential (n = 49) or obesity-induced hypertension (n = 79), uraemic patients (n = 20), and also in obese normotensive patients (n = 60) and age-matched controls (n = 57). Methods: The PON1 activity was measured via paraoxon hydrolysis. The PON1 genotype was determined by real-time PCR. The levels of oxidized and reduced glutathione, the end-products of nitric oxide, cysteine, homocysteine and lipid peroxidation in the plasma were measured and related to the PON1 status. Results: There were no significant differences between the patient groups and the control group in the genotype distributions and the allele frequencies of the Q192R polymorphism. The PON activity was significantly lower (p < 0.001) in the uraemic hypertensive group than in the controls. The MDA concentration was significantly higher in the uraemic hypertensive (p < 0.001) and obese hypertensive (p < 0.05) patients. The plasma NOx concentrations were significantly lower (p < 0.001) and the ratio MDA/NOx were significantly higher in all four patient groups. The GSH levels were significantly lower in the patients with hypertension (p < 0.001) and obesity-induced hypertension (p < 0.05) than in the controls, while the GSSG level (p < 0.01) and the ratio GSSG/GSH (p < 0.05) was significantly higher in the uraemic hypertensive group. The plasma homocysteine level was significantly higher (p < 0.001) in the uraemic hypertensive patients as compared with the controls. Conclusions: We found no significant correlation between the biochemical parameters and neither genotypes nor enzyme activities. The PON1 status and the levels of certain biochemical parameters are independently associated with the hypertension in hypertensive and obese hypertensive patients, and the elevated levels of lipid peroxides and plasma homocysteine may contribute to the increased risk of cardiovascular complications in patients on haemodialysis.

Genetic polymorphisms and the risk of progressive renal failure in elderly Hungarian patients.

The relationship between renal disease progression and genetic polymorphism of enzymes influencing endothelial function remains incompletely understood. We genotyped three cohorts of elderly Hungarian patients: 245 patients with end‐stage renal disease (ESRD) on chronic hemodialysis (HD), 88 patients with mild chronic kidney disease (CKD), and 200 healthy controls. The underlying diagnoses of renal diseases were primary glomerulonephritis, interstitial nephritis, hypertension, diabetic nephropathy, and hereditary diseases. We examined genetic polymorphisms of eight candidate genes associated with endothelial function: endothelial constitutive nitric oxide synthase (ecNOS) T‐786C, endothelin‐1 G5727T, methylenetetrahydrofolate reductase (MTHFR) C677T, paraoxonase‐1 Q192R and M55L, angiotensinogen M235T, angiotensin‐converting enzyme (ACE) I/D and angiotensin II type 1 receptor A1166C gene. Six gene polymorphisms were detected by real‐time polymerase chain reaction with melting‐point analysis, and two via allele‐specific amplification and gel electrophoresis. Control group patients were in Hardy‐Weinberg equilibrium for all tested genotypes. In ESRD patients attributed to hypertension, the endothelin gene G5727T GG genotype occurred significantly less but GT genotype more frequently (P < 0.01 for both). In ESRD patients attributed to primary glomerulonephritis, more ACE DD and less ID genotypes were found (P < 0.02 for both) than in the controls. The underlying diagnosis may modify the association of genetic polymorphism and dialysis‐dependent ESRD.

Different pathomechanisms of essential and obesity-associated hypertension in adolescents

Obesity-induced hypertension and essential hypertension in lean patients are two different forms of hypertension. The main goal of this study was to test whether there are differences in biochemical parameters between subjects with obesity-associated hypertension and those with essential hypertension. We examined whether the biochemical responses to angiotensin-converting enzyme inhibitor (ACEI) ramipril therapy reveal properties of these two conditions that might explain the differences in clinical outcome. Before ramipril therapy, the hypertensive group exhibited increases in ACE activity (p<0.05), plasma malondialdehyde (MDA) concentration and the malondialdehyde/nitric oxide end-product ratio (MDA/NOx) (p<0.05), and decreases in xanthine oxidase (XO) activity (p<0.05) and plasma nitric oxide end-product (NOx) level (p<0.01). Before medication, plasma endothelin-1 (ET-1), plasma leptin, and leptin receptor levels were normal. Following ramipril treatment, ACE activity normalized. Before ACE inhibitor treatment, the obese-hypertensive group exhibited elevated levels of plasma ET-1 (p<0.05), plasma leptin (p<0.01), XO activity (p<0.05), plasma MDA and MDA/NOx (p<0.05), and reduced levels of plasma NOx(p<0.01) and leptin receptors (p<0.001). Following medication, the plasma NOx level, MDA/NOx, and XO activity returned to normal while ACE activity decreased (p<0.001). In patients with essential hypertension, NO availability and ACE activity, and in those with obesity-associated hypertension, hyperleptinemic effects, NO level, endothelin-1 concentration and XO activity, may be important factors in the pathology.

Microvascular reactivity in lean, overweight, and obese hypertensive adolescents

The microvascular responses to endothelium-dependent vasodilators (e.g., acetylcholine), endothelium-independent vasodilators (e.g., sodium nitroprusside), and to local heating were studied (for the first time) in adolescents with essential hypertension, grouped according to their body mass index. The forearm microvascular reactivities of thirty-three hypertensive adolescents (ten lean, 13 overweight, and ten obese) and 19 healthy controls were assessed by means of laser Doppler flowmetry. Blood levels of enzymatic and nonenzymatic antioxidants and malondialdehyde were determined. The perfusion increments in response to acetylcholine iontophoresis were not significantly attenuated in the patient groups as compared with the controls. Sodium nitroprusside (SNP) iontophoresis resulted in significantly smaller perfusion increments in the lean and obese hypertensives than in the controls (both p < 0.05). Similar responses to local heating (44°C) performed after either acetylcholine or SNP iontophoresis were observed at the respective measurement sites. As compared with the controls, we found elevated ratios of the whole blood oxidized and reduced glutathione in all the patient groups (all p < 0.001), increased erythrocyte catalase activities in the overweight hypertensives (p < 0.05), and decreased ratios of the plasma alpha-tocopherol and triglycerides in the obese hypertensive group (p < 0.05). Conclusion: The endothelium-dependent microvascular reactivity was not significantly attenuated in the hypertensive adolescents in contrast with the impaired endothelium-independent vasorelaxation in the lean and obese hypertensives.

International comparison of blood pressure and BMI values in schoolchildren aged 11–16 years

Aims:  This study comprised part of a larger cross‐sectional survey performed in Hungary in the period 2005–2006, which was designed first to reveal the representative age‐, gender‐ and height‐specific percentile values for the systolic blood pressure (SBP) and the diastolic blood pressure (DBP) in Hungarian children aged 11–16 years. The second aim was to determine the prevalence of overweight and obesity.

Blood pressure reference tables for Hungarian adolescents aged 11-16 years.

Background/Aims: Blood pressure (BP) during childhood is an established predictor of adult BP, which in turn predicts mortality in the event of cardiovascular disease. Reference data for systolic (SBP) and diastolic (DBP) BP are not available for Hungarian children (aged 11–14 years). The aim was to make up for this deficit. Methods: Analyses were performed on 14,504 Hungarian children aged 11–16 years. All measurements were made with a validated, automated device. Criteria described by international guidelines were used. Results: The 50th, 90th and 95th percentile BP values were defined by dividing the participating population into age-, gender- and height-specific subgroups. The SBP increased linearly with age to an apparent plateau at around the age of 15–16 years in both girls and boys, and there were similar increases in DBP and mean arterial pressure. Both the SBP and DBP revealed highly significant correlations in both genders with weight (SBP: r = 0.452, p < 0.01; DBP: r = 0.340, p < 0.01), height (SBP: r = 0.314, p < 0.01; DBP: r = 0.245, p < 0.01) and body mass index (SBP: r = 0.407, p < 0.01; DBP: r = 0.294, p < 0.01). Conclusion:The present study provides reference data on SBP and DBP, facilitating the diagnosis of essential hypertension in the 11- to 16-year age group.

Simultaneous determination of 3-hydroxypropionic acid, methylmalonic acid and methylcitric acid in dried blood spots: Second-tier LC-MS/MS assay for newborn screening of propionic acidemia, methylmalonic acidemias and combined remethylation disorders

Background and aims Increased propionylcarnitine levels in newborn screening are indicative for a group of potentially severe disorders including propionic acidemia (PA), methylmalonic acidemias and combined remethylation disorders (MMACBL). This alteration is relatively non-specific, resulting in the necessity of confirmation and differential diagnosis in subsequent tests. Thus, we aimed to develop a multiplex approach for concurrent determination of 3-hydroxypropionic acid, methylmalonic acid and methylcitric acid from the same dried blood spot (DBS) as in primary screening (second-tier test). We also set out to validate the method using newborn and follow-up samples of patients with confirmed PA or MMACBL. Methods The assay was developed using liquid chromatography–tandem mass spectrometry and clinically validated with retrospective analysis of DBS samples from PA or MMACBL patients. Results Reliable determination of all three analytes in DBSs was achieved following simple and fast (<20 min) sample preparation without laborious derivatization or any additional pipetting steps. The method clearly distinguished the pathological and normal samples and differentiated between PA and MMACBL in all stored newborn specimens. Methylcitric acid was elevated in all PA samples; 3-hydroxypropionic acid was also high in most cases. Methylmalonic acid was increased in all MMACBL specimens; mostly together with methylcitric acid. Conclusions A liquid chromatography–tandem mass spectrometry assay allowing simultaneous determination of the biomarkers 3-hydroxypropionic acid, methylmalonic acid and methylcitric acid in DBSs has been developed. The assay can use the same specimen as in primary screening (second-tier test) which may reduce the need for repeated blood sampling. The presented preliminary findings suggest that this method can reliably differentiate patients with PA and MMACBL in newborn screening. The validated assay is being evaluated prospectively in a pilot project for extension of the German newborn screening panel (‟Newborn screening 2020”; Newborn Screening Center, University Hospital Heidelberg).

Anyai és újszülöttkori B12-vitamin-hiány felismerése kiterjesztett újszülöttkori szűréssel

Absztrakt: Bevezetes: A csecsemőkori B12-vitamin-hiany sulyos neurodegenerativ betegsegkent jelenhet meg, es rendszerint vegetarianus etrend vagy anaemia perniciosa kovetkezteben letrejovő anyai hiany okozza. Korai felismeresevel es kezelesevel a potencialisan sulyos es irreverzibilis neurologiai karosodas megelőzhető. Biokemiailag a B12-vitamin-hiany metil-malonsav-, homocisztein- es propionil-karnitin-felhalmozodashoz vezet. A tandem tomegspektrometrias kiterjesztett ujszulottkori szűres azonosithatja az ujszulottkori es anyai B12-vitamin-hianyt, a propionil-karnitinnek es egyeb metabolitoknak az ujszulottek beszaritott vercseppmintajaban tortenő meresevel. Celkitűzes: A B12-vitamin-hiany szűresevel nyert tapasztalataink osszefoglalasa. Modszer: Retrospektiv modon elemeztuk a Szegedi Szűrőkozpontban diagnosztizalt B12-vitamin-hianyos csecsemők klinikai es laboratoriumi adatait. Eredmenyek: Magyarorszagon a kiterjesztett ujszulottkori szűres 2007-ben kerult bevezetesre. Kozpontunkban azota korulbelul 395...