Michael Karamouzis

Increase in Oxidative Stress but Not in Antioxidant Capacity with Advancing Stages of Chronic Kidney Disease

Background/Aims: Increased oxidative stress in chronic kidney disease (CKD) was suggested to be both a cause and an effect of renal injury. However, the evolution of oxidant stress from early stages of renal function decline is not fully clear. This study aimed to determine the oxidant-antioxidant balance across the whole range of renal function. Methods: A total of 116 patients with CKD (85 predialysis patients divided into groups according to CKD stage, and 31 patients with end-stage renal disease (ESRD) on hemodialysis treatment), as well as 29 healthy subjects were evaluated. Plasma levels of 15-F2t-isoprostane (15-F2t-IsoP), a valid marker of oxidant stress, as well as total antioxidant capacity (TAC) and serum levels of vitamin E were measured in all participants. Results: Plasma 15-F2t-IsoP levels were higher in predialysis and ESRD patients compared to healthy subjects and were progressively increasing with advancing CKD stages (p < 0.001). In contrast, plasma TAC was similar between healthy subjects and predialysis patients, and presented a small reduction in ESRD patients (p < 0.001). Vitamin E levels were higher in healthy subjects compared to any other group (p < 0.001) and slightly higher in ESRD patients compared to predialysis patients (p < 0.01), but did not differ significantly between the groups of predialysis patients. Plasma 15-F2t-IsoP levels were inversely correlated with estimated glomerular filtration rate in predialysis patients (r = –0.65, p < 0.001). Conclusions: This study shows that 15-F2t-IsoP levels increase progressively with advancing CKD stages, whereas TAC and vitamin E levels remain rather stable with the loss of renal function and change only in patients with ESRD.

Insulin improves clinical status of patients with cystic-fibrosis-related diabetes mellitus.

Cystic‐fibrosis‐related diabetes mellitus is frequently underdiagnosed and associated with deterioration of overall clinical status. The purpose of this prospective study was to investigate the influence of insulin on nutrition, lung function and clinical status of cystic fibrosis patients. For a period of 5y, and at 6‐mo intervals, body mass index, forced expiratory volume in 1 sec, Shwachman score, intravenous glucose tolerance test and first‐phase insulin response were determined in 30 cystic fibrosis patients (age range 10–35 y) with exocrine pancreatic insufficiency. During the study period, six patients (3M and 3F; age range 15–22 y) developed diabetes and required insulin therapy. The decrease of first‐phase insulin response coincided with deterioration of nutritional and clinical status, which improved significantly 6 mo after the institution of insulin.

Enhanced oxidative stress and platelet activation combined with reduced antioxidant capacity in obese prepubertal and adolescent girls with full or partial metabolic syndrome.

In adults, obesity is a main factor implicated in increased oxidative stress (OS), platelet activation (PA) and impaired antioxidant status (AS), all predisposing factors for cardiovascular disease leading to increased morbidity and mortality. Furthermore, the metabolic syndrome (MetS) is an important cardiovascular risk factor, which progressively develops and may already be present during late childhood or adolescence. However, scarce data exist on oxidative-antioxidant balance and PA in childhood and adolescence in the presence of partial (PMetS) or full MetS. The aim of the study was to evaluate OS, PA, and AS in prepubertal and adolescent obese girls with partial or full MetS. 96 girls with a clinical and metabolic evaluation for obesity and 44 healthy normal-weight sex- and age-matched girls were studied. IDF-adopted criteria were used to define full and partial MetS and the patient population was divided into 4 groups: the first comprised 31 pre-pubertal girls with PMetS (PR-PMetS), the second 37 adolescents with PMetS (AD-PMetS), the third 10 prepubertal girls with full MetS (PR-MetS), and the fourth 18 adolescents with full MetS (AD-MetS). The OS was evaluated by measuring plasma 15-F(2t)-Isoprostane levels (15-F(2t)-IsoP) and protein carbonyls, PA by thromboxane B(2) levels (TXB(2)), and AS by serum vitamin E and plasma total antioxidant capacity (TAC) levels. 15-F(2t)-IsoP, protein carbonyls, and TXB(2) levels were significantly gradually amplified, and vitamin E and TAC reduced, and significantly correlated with obesity from childhood to adolescence and from partial to full MetS. This study demonstrates the loss of the normal homeostatic balance between oxidant-antioxidant state in obese children and adolescents with manifestations of partial and full MetS.

Insulin resistance and hyperinsulinemia in prepubertal obese children.

BACKGROUND Tissue resistance to insulin has been demonstrated in obese individuals. Pancreatic beta-cells respond to the reduced tissue sensitivity with increased insulin secretion so that glucose homeostasis is maintained. OBJECTIVE The purpose of this prospective study was to investigate the presence of hyperinsulinemia and insulin resistance in obese children and adolescents. SUBJECTS AND METHODS Fasting glucose (FG) and insulin (FI) levels and fasting glucose to insulin ratio (FGIR) were measured in 26 obese prepubertal children and 20 obese adolescents, as compared to 20 non-obese prepupertal children and 20 adolescents with normal body weight. Furthermore, obese children and adolescents underwent an oral glucose tolerance test with measurements of glucose and insulin 2 hours post glucose load. RESULTS In 14/26 (54%) obese prepubertal children and in 16/20 (80%) obese adolescents FI was >24 microU/ml. FGIR was <6 in 23/26 (88%) prepubertal obese children and in all obese adolescents. All non-obese prepubertal children and adolescents had normal FI. However, FGIR was <6 in 6/20 (30%) non-obese prepubertal children and in 15/20 (75%) non-obese adolescents. CONCLUSION Hyperinsulinemia and insulin resistance are already present in prepubertal obese children. As hyperinsulinemia is a potentially reversible condition and the complications related to it may be prevented, early measurements should be undertaken so that obese children lose body weight before the onset of puberty which may enhance the problem of insulin insensitivity.

Morning and Evening Plasma Melatonin and Dexamethasone Suppression Test in Patients with Nonseasonal Major Depressive Disorder from Northern Greece (Latitude 40–41.5°)

Introduction: The present study aimed to search for correlations between melatonin (MT) levels and the dexamethasone suppression test (DST) and clinical variables. Methods: Fifty depressed patients aged 21–60 years took part in the study. The Schedules for Clinical Assessment in Neuropsychiatry, version 2.0, and the International Personality Disorders Examination were used for diagnosis. Psychometric assessment included the Hamilton Depression Rating Scale, the Hamilton Anxiety Scale, the General Assessment of Funtioning Scale, the Newcastle scales and the Diagnostic Melancholia Scale. The DST and 9.00 and 23.00 h MT values were assessed. Statistical analysis included Student’s t test, Pearson product moment correlation coefficient and forward stepwise multiple linear regression analysis. Results: Melancholic patients had lower 23.00 h MT values in comparison to the rest of the patients and the atypical and ‘undifferentiated’ patients. Conclusion: The current study shows that low MT values were closely related to melancholic depression. Distinct quality of mood, psychomotor agitation or retardation and anorexia or weight loss seemed to be responsible for this relationship.

Autoantibodies Predicting Diabetes mellitus Type I in Celiac Disease

Celiac disease (CD) and diabetes mellitus type I (DM-I) are both autoimmune diseases. Abnormal first-phase insulin response (FPIR) is associated with the prediabetic phase. Glutamic acid decarboxylase (GAD) and islet cell antibodies (ICAs) – especially the tyrosine phosphatase-like protein IA-2 antibodies – are considered to be serological markers of DM-I future development. The aim of this study is to investigate the presence of autoantibodies (GAD, IA-2) in individuals with CD, on a gluten-free diet, who have normal intestinal morphology. Thirty patients with CD (4–22, mean 15 years), 30 newly diagnosed diabetic children (2.5–16, mean 10 years) and 30 healthy subjects (7–35, mean 18 years) were investigated. Serum GAD and IA-2 autoantibodies were assessed by a quantitative enzyme-linked immunosorbent assay (ELISA) method in all patients and controls. Seven CD patients (23%), 28 diabetic children (93%) and none in the control group had positive GAD and IA-2 antibodies. The FPIR was normal in CD patients (≥46 mU/l). Conclusions: GAD and IA-2 antibodies are detected in 23% of patients with CD. These patients may be at risk to develop DM-I. Regular follow-up and determination of FPIR for the early diagnosis of the prediabetic phase in patients with CD having circulating autoantibodies is recommended.

Osteopenia in Children and Adolescents with Hyperprolactinemia

Three patients with hyperprolactinemia due to pituitary adenomas (two patients) or empty sella (one patient) and osteopenia are described. Their ages at presentation ranged from 8 to 17 years. Each patient was treated with cabergoline. Serum prolactin levels became normal in all patients within one month. Bone density and pubertal stage improved after 12 months of treatment.

Islet autoantibodies and insulin dependent diabetes mellitus in cystic fibrosis.

Cystic fibrosis-related diabetes mellitus (CF-DM) is thought to be secondary to beta-cell destruction by fibrous tissue replacing the exocrine pancreas. The aim of this study was to investigate the hypothesis that other factors may also be responsible. Glutamic acid decarboxylase (GAD) and islet cell (IA-2) antibodies were measured by quantitative ELISA in a group of patients with CF (n=30) in comparison to a group of newly diagnosed DM type 1 (IDDM) patients (n=30) and normal subjects (n=30). GAD antibodies were positive (>32 ng/ml) in 50% of the CF, 93% of the IDDM and 0% of the control group. IA-2 antibodies were detected (>0.9 U/ml) in 40% of the CF, 93% of the IDDM and 0% of the control group. Among the fifteen CF patients with positive GAD and IA-2 antibodies, four already had IDDM and another five abnormally low (<45 mU/l) first phase insulin response (FPIR) indicating a prediabetic state. We conclude that factors other than mechanical may be involved in the development of CFDM. The presence of autoantibodies predicting IDDM supports the hypothesis that CF-DM may have a multifactorial pathogenesis.

Early Decreases in Plasma Lipid Transfer Proteins During Weight Reduction

Objective: To determine the effect of short‐term weight loss in obese women on concentrations of plasma cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP), two new risk factors for cardiovascular disease.

Plasma TSH, T3, T4 and cortisol responses to swimming at varying water temperatures.

The acute effect of 30-min swimming at a moderate speed, at three water temperatures (20, 26 and 32 degrees C) on plasma thyroid stimulating hormone (TSH), free thyroxine (F.T4), triiodothyronine (T3) and cortisol concentrations was studied in 15 élite male swimmers. Blood was sampled before and immediately after the events. The heart rate, which was continuously monitored during exercise, had the highest response at 32 degrees C and the lowest at 20 degrees C. Blood lactate concentrations were found to be similar after the three tests. Plasma TSH and F.T4 were found to be significantly increased (by 90.4% and 45.7% respectively) after swimming at 20 degrees C, decreased at 32 degrees C (by 22.3% and 10.1% respectively) and unchanged at 26 degrees C. Exercise at these three water temperatures did not significantly affect T3. Finally, plasma cortisol was found to be increased after swimming at 32 degrees C (by 82.8%) and 26 degrees C (by 46.9%), but decreased at 20 degrees C (by 6.1%).