Filia Apostolakou

Assessment of oxidative stress in patients with sickle cell disease: The glutathione system and the oxidant-antioxidant status.

Continuous reactive oxygen species (ROS) production in individuals with sickle cell disease (SCD) may alter their overall redox status and cause tissue damage. The aim of this study was to evaluate oxidative stress in patients with SCD using two new assays, FORT (free oxygen radical test) and FORD (free oxygen radical defense) along with assessment of glutathione system including superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GPx) activities, vitamins A, C and E, malondialdehyde (MDA), non-transferrin bound iron (NTBI) and nitric oxide (NO) concentrations. A total of 40 patients with SCD and 25 apparently healthy volunteers (control group) were enrolled in the study. Components of glutathione system, vitamins A, C, and E, and malondialdehyde were determined with reverse-phase HPLC, non-transferrin bound iron (NTBI) was assessed with atomic absorption spectroscopy using graphite furnace, superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GPx) activities were determined spectrophotometrically in red cell lysates, nitric oxide (NO) was detected colorimetrically, while FORT and FORD using colorimetric assays, as two point-of-care tests. The findings revealed significant impairment of the glutathione system indicated by reduced GSH(total) (p<0.00001), GSH(reduced) (p<0.00001) and GSSG (p>0.056) values of SCD patients compared to the control group. ROS expressed as FORT were significantly increased (p<0.00001), while antioxidant defense expressed as FORD was significantly reduced (p<0.02) in SCD group compared to the control group. Age and genotype of the patients as well as therapy of their disease appeared to play no role in their oxidative status.

FORT and FORD: two simple and rapid assays in the evaluation of oxidative stress in patients with type 2 diabetes mellitus.

The aim of the study was to evaluate the levels of free oxygen radicals and free oxygen radicals defense in patients with newly diagnosed type 2 diabetes mellitus (T2DM). The disease seems to be involved strongly in the production of reactive oxygen species. Forty-five patients with newly diagnosed T2DM and 20 apparently healthy individuals (control group) were included in the study. Reactive oxygen species were determined using the free oxygen radicals (FORT) test, which is based on the Fenton reaction. In this method, the hydroperoxides reacted with the transition metal ions liberated from the proteins and were converted to alkoxy and peroxy radicals. The radical species produced by the reaction, which are directly proportional to the quantity of lipid peroxides, interact with an additive that forms a radical molecule. Similarly, the free oxygen radicals defense (FORD) test uses preformed stable and colored radicals and determines the decrease in absorbance that is proportional to the blood antioxidant concentration. We found that (a) FORT levels were increased in diabetic patients (2.86 +/- 0.56 mmol/L H(2)O(2)) compared with controls (1.87 +/- 0.26 mmol/L H(2)O(2)) (P < .0001) and (b) FORD levels were lower in diabetic patients (1.23 +/- 0.18 mmol/L Trolox) compared with controls (1.34 +/- 0.14 mmol/L Trolox) (P < .01). The intraassay and interassay coefficients of variation were 3.7% and 6.2%, respectively, for FORT and 4.2% and 6.6%, respectively, for FORD. Determination of free oxygen radicals and free oxygen radicals defense seems to play an important role in the generation and evaluation of oxidative stress, an imbalance between oxidants and antioxidants that can lead to oxidative damage and is involved in the pathogenesis of several diseases, such as T2DM.

Serum lipid alterations in acute lymphoblastic leukemia of childhood.

Epidemiologic studies have indicated a relationship between serum lipids and cancer, and it is possible that lipid abnormalities are involved in the mechanism of oncogenesis. This study was performed to investigate serum lipid alterations in patients with acute lymphoblastic leukemia (ALL) at diagnosis and during remission of the disease. Plasma lipids and lipoproteins were measured at diagnosis, prior to the administration of induction treatment, and every 2 months for the first 12 months of the maintenance phase of chemotherapy in 64 patients with ALL. Nearly all patients demonstrated a predictable pattern of serum lipid alterations that consisted of extremely low levels of high-density lipoprotein cholesterol, elevated triglycerides, and elevated low-density lipoprotein cholesterol. Patients studied again during remission demonstrated a return to normal values, and the difference was statistically significant. The results suggest that at diagnosis of ALL an abnormality in lipid metabolism is present, which is reversed during remission.

Increased circulating High-Sensitivity Troponin T concentrations in children and adolescents with obesity and the metabolic syndrome: A marker for early cardiac damage?

OBJECTIVE Childhood obesity is associated with an increased risk for atherosclerosis mediated by the pathogenetic mechanisms that lead to the development of the Metabolic Syndrome (MetS). High-Sensitivity Troponin T (hs-TnT) is a specific marker of ischemic myocardial damage, whereas a minimal elevation of this biomarker has been found in adults with a high-risk for cardiovascular disease. We hypothesized that hs-TnT might be altered in obese children with and/or without the Mets. MATERIALS AND METHODS Fifty-seven (34 males) obese and 25 non-obese (6 males) children were assessed at the Childhood Obesity Clinic of our department. Obesity was defined using the IOTF criteria. Metabolic syndrome was defined with the IDF criteria. Hs-TnT was measured using an electrochemiluminescence-based assay. RESULTS The entire group of obese children had significantly higher hs-TnT concentrations [4.1 ± 3.4 ng/L] (p=0.029) than the non-obese ones [3.0 ± 0.2 ng/L), however, in both groups the levels of the cardiac biomarker were within the normal range. Comparison of the obese children with or without the MetS and the non-obese, revealed that those with the MetS had significantly higher hs-TnT (6.7±7.1 ng/L) than the obese without MetS (3.7 ± 2.1 ng/L) [p=0.044], and the non-obese [p=0.014]. Hs-TnT did not differ between the obese without MetS and the non-obese. CONCLUSIONS Circulating concentrations of hs-TnT in obese children with the MetS are higher than those of the obese without the MetS and the non-obese, suggesting that it is obesity-related metabolic changes rather than obesity per se linked to increased hs-TnT in children.

Correlation of NT-proBNP levels and cardiac iron concentration in patients with transfusion-dependent thalassemia major.

Iron-induced cardiotoxicity remains the leading cause of morbidity and mortality in patients with transfusion-dependent β-thalassemia major. Heart failure in these patients, which may be reversible but has a poor prognosis, is characterized by myocardial iron deposition-related early diastolic dysfunction. Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is a sensitive biomarker for the detection of asymptomatic left ventricular dysfunction. In this study, we prospectively evaluated plasma NT-proBNP levels in 187 adult patients aged 19-54 years with β-TM. Possible correlations with the proposed recently cardiac iron concentration based on an equation derived from heart T2* assessment by MRI: [Fe] = 45.0 × [T2*](-1.22) with [Fe] in milligrams per gram dry weight and T2* in milliseconds were explored. We found that: 143 patients had no cardiac hemosiderosis, defined as [Fe] < 1.1 mg/g dry weight, corresponding to T2* > 20 ms and 44 patients had cardiac hemosiderosis, defined as [Fe] > 1.2mg/g dry weight. The main results of the study showed that: a) NT-proBNP levels were markedly increased in thalassemic patients (152.2 ± 190.1 pg/mL, ranged from 6.0 to 1336.0 pg/mL compared to normal control levels 40.1 ± 19.7 pg/mL, p < 0.001, b) NT-proBNP levels were significantly higher in patients with cardiac hemosiderosis compared to patients without cardiac hemosiderosis (185.1 ± 78.0 vs 128.9 ± 20.2 pg/mL, p < 0.05), c) NT-proBNP levels correlated with [Fe] values (r = 0.387, p < 0.001). This correlation was significant in patients with cardiac hemosiderosis (r = 0.520, p < 0.001), but not in patients without cardiac hemosiderosis (p > 0.1), and d) no significant correlation was found between NT-proBNP levels and left ventricular ejection fraction values, (p > 0.3). Our study demonstrated for first time the significant association of NT-proBNP levels and cardiac iron concentration in patients with β-thalassemia major linking blood chemistry and imaging techniques. Multicenter studies of these parameters during iron chelation therapies are needed to validate their association and further exploit its clinical use.

Disparity in circulating adiponectin multimers between term and preterm infants

Abstract Aims: To study circulating levels and distribution of adiponectin multimers [low molecular weight (LMW)-, medium molecular weight (MMW)- and high molecular weight (HMW)-adiponectin] in preterm and full-term infants. Methods: Total serum adiponectin and its multimers were measured in 40 healthy infants at the age of one month and associations with anthropometric parameters [body weight and length, body mass index (BMI)], weight gain and metabolic indices (glucose, insulin) were examined. Twenty of the infants were born preterm (gestational age 33.2±1.6 weeks). Results: LMW-adiponectin level and its fractional ratio to total adiponectin were significantly higher in full-term than in preterm infants (P<0.001 and P<0.01, respectively), whereas, MMW-adiponectin level and its ratio were significantly lower (P=0.03 and P=0.01, respectively). HMW-adiponectin did not differ significantly between full-term and preterm infants and accounted for almost 60% of total adiponectin levels in both groups. HMW-adiponectin, but not MMW adiponectin or LMW adiponectin, correlated significantly with anthropometric measurements, similarly to total adiponectin; in addition, HMW adiponectin correlated significantly with weight gain. Conclusions: HMW adiponectin is the most prevalent form in infants. Circulating levels and distribution of MMW- and LMW-adiponectin differ between full-term and preterm infants, but the role of these adiponectin multimers needs to be studied further.

Growth Differentiation Factor 15 Is a New Biomarker for Survival and Renal Outcomes in Light Chain (AL) Amyloidosis

Growth differentiation factor-15 (GDF-15) improves prognostication in patients with cardiovascular disorders in addition to conventional cardiac markers (N-terminal pro B-type natriuretic peptide [NT-proBNP], troponins [Tns]) and has shown prognostic value in patients with renal diseases. In patients with light chain (AL) amyloidosis, cardiac involvement is the major determinant of prognosis, and cardiac markers define prognosis, whereas biomarkers of renal involvement stratify renal risk. We explored the prognostic importance of serum level of GDF-15 in patients with AL amyloidosis in 2 independent cohorts. The prognostic value of GDF-15 level was initially evaluated in a cohort of 107 consecutive previously untreated patients with AL amyloidosis from Athens, Greece, and was then validated in a second cohort of 202 consecutive previously untreated patients from Pavia, Italy. High GDF-15 level was associated with a higher risk of early death and poor overall survival independently of NT-proBNP and high-sensitivity TnT (hsTnT) or hsTnI levels. At the 6-month landmark, reduction of GDF-15 level ≥25% was associated with improved outcome. GDF-15 level ≥4000 pg/mL was associated with a high risk of progression to dialysis, independently of renal risk defined by estimated glomerular filtration rate and proteinuria, in both cohorts; failure to reduce GDF-15 below this level was associated with increased risk at either the 3- or 6-month landmark, independently of the established renal response or progression criteria. In conclusion, GDF-15 has prognostic implications for different outcomes in patients with AL and adds prognostic information independent of that provided by cardiac and renal risk biomarkers.

Hair cortisol concentrations exhibit a positive association with salivary cortisol profiles and are increased in obese prepubertal girls

Abstract Cortisol, a key mediator of the stress response, has been associated with obesity and metabolic syndrome manifestations as early as in childhood. Scalp hair cortisol has been proposed as a reliable index of long-term circulating cortisol. We aimed to investigate whether obese prepubertal girls have higher scalp hair cortisol than normal-weight controls and whether hair cortisol levels are correlated with salivary cortisol concentrations in these groups. In this cross-sectional study, 25 obese girls and 25 normal-weighted, age-matched girls were enrolled. Anthropometric evaluation, blood chemistry and salivary cortisol measurements were performed, and body mass index (BMI) and areas under the curve with respect to ground (AUCg) were calculated. Hair cortisol determination was performed with liquid chromatography–tandem mass spectrometry. Both hair cortisol concentrations and salivary cortisol AUCs were higher in the obese than the normal-weight girls (p < .001 and p = .002, respectively). A positive correlation between hair cortisol and BMI Z-score was found (rho = .327, p = .025), while hair cortisol correlated positively with salivary cortisol AUCg (rho = .3, p = .048). We conclude that obese prepubertal girls have higher hair and salivary cortisol concentrations than their age-matched lean counterparts. Hair cortisol assessment seems to be a sensitive method of evaluating systemic cortisol exposure, which is supported by our finding that hair cortisol is associated with salivary concentrations of the hormone. Lay Summary: Cortisol is the key hormone of the stress response. Childhood obesity has been associated with cortisol production dysregulation. Our findings suggest a positive association between obesity in prepubertal girls and elevated cortisol concentrations, measured in saliva and hair.

Increased placental growth factor (PlGF) concentrations in children and adolescents with obesity and the metabolic syndrome.

OBJECTIVE: Childhood obesity and the Metabolic Syndrome (MetS) are associated with an increased risk for early onset endothelial dysfunction and atherosclerosis. Placental growth factor (PlGF), a member of the vascular endothelial growth factor family, plays an important role in atherosclerosis by stimulating angiogenesis and atherogenic migration of monocytes/macrophages into the arterial wall. The aim of this study was to investigate differences in circulating PlGF concentrations between children with obesity/metabolic syndrome and non-obese children. We have previously shown increased high-sensitivity troponin (hs-TnT) concentrations in children with MetS from the same cohort. DESIGN: Fifty-seven obese (49 without and 8 with MetS) and 25 non-obese children (controls) were assessed at the Childhood Obesity Clinic of our Department. Obesity was defined using the IOTF criteria. MetS was defined based on the IDF criteria. PlGF was measured using electrochemiluminescence methodology. RESULTS: Mean PIGF concentrations of obese children were significantly higher (p=0.048) compared with those of the controls. Analysis of the three groups, the obese (without MetS), the MetS and the control, demonstrated a significant difference in PlGF concentrations (p=0.035). Subgroup analysis revealed increased PlGF concentrations in children with the MetS compared to the controls (p=0.009). Troponin had a significant positive correlation with PlGF overall (p=0.003) and in the obese group (p=0.046). CONCLUSIONS: Increased serum concentrations of PlGF, a biomarker of angiogenesis, are found in obese children with the MetS compared to non-obese controls, whereas PlGF correlated positively with troponin. Longitudinal studies may reveal the prognostic role of this biomarker in the progression of atherosclerosis in obese children with the MetS.

Mothers’ parenting stress is associated with salivary cortisol profiles in children with attention deficit hyperactivity disorder

Abstract The aim of this study was to explore the relation between mothers’ parenting stress and the functioning of the hypothalamic–pituitary–adrenal axis (HPAA), as expressed by daily salivary cortisol concentrations, in their children diagnosed with attention deficit hyperactivity disorder (ADHD). Seventy-five children aged 6–11 years diagnosed with ADHD predominant hyperactive-impulsive/combined (ADHD–HI/C, N = 49) and inattentive symptoms (ADHD–I, N = 26) and 45 healthy peers and their mothers participated in the study. Μothers completed measures assessing their children’s ADHD status, perceived parenting stress (Parenting Stress Index – Short Form, PSI–SF), mothers’ symptoms of psychopathology, social support and socioeconomic status. Children’s salivary cortisol samples were collected at six different time points on a single day. Mothers of children with ADHD–HI/C reported higher levels of parenting stress than mothers of children with ADHD–I and controls. All PSI–SF subscales showed significant associations with children’s cortisol awakening response (CAR) in both ADHD groups, with the exception of the parental distress subscale in the ADHD–I group. In both ADHD groups, the parent–child dysfunctional interaction subscale, the difficult child subscale and the PSI total score were significantly associated with children’s CAR. An interrelation is revealed between mothers’ high levels of parenting stress and HPAA functioning in children with ADHD. In this population, CAR has been identified as a sensitive peripheral measure of HPAA functioning in children. Lay summaryThis study showed that in families of children diagnosed with ADHD, there is a complex relation between the mothers’ high levels of parenting stress and children’s atypical hypothalamic–pituitary–adrenal axis functioning.