Evangelos D. Papakonstantinou

Homocysteine and other vascular risk factors in patients with phenylketonuria on a diet

The aim of this study was to investigate the known risk factors, such as lipids, homocysteine and endothelin, for the development of coronary artery disease (CAD) in phenylketonuria (PKU) patients, depending on their diet. The PKU patients (n= 74) were divided into two groups. Group A (n= 34; mean age 6.78 ± 1.5 y) adhered strictly to a diet and group B (n= 40; mean age 8.0 ± 3.2 y) did not comply with the diet. The control group comprised 50 healthy non‐PKU children. All groups were evaluated for blood levels of homocysteine and vitamin B6 by high‐performance liquid chromatography, vitamin B12 and folate in serum by a radioassay, lipids by a routine method, and lipoprotein(a) and endothelin‐1 with an immunoassay. Homocysteine levels (28.65 ± 3.3 μmol 1‐1) were increased in group A compared with group B (6.86 ± 1.6 μmol 1‐1) and the controls (6.9 ± 2.0 μmol 1‐1) (p > 0.001). Vitamin B6 (10.7 ± 10.9 nmol 1‐1), vitamin B12 (98.5 ± 22.3 pmol 1‐1), folate (2.35 ± 1.3 nmol 1‐1) and lipids were decreased in group A. The other vascular risk factors, which were not dependent on diet [lipoprotein(a) and endothelin‐1], did not differ among the three groups.

Psychological and sympatho‐adrenal status in patients with cystic acne

Patients with cystic acne (CA) frequently report feeling self conscious, anxiety and social isolation.

The Effect of Isotretinoin on Biotinidase Activity

Background: Among the reaction and effects of isotretinoin, mucocutaneous reactions, xerosis and erythema of the skin as well as elevation of liver enzymes and lipids except high density lipoprotein have been reported. Objective: Since biotinidase is mainly produced in the liver and partial biotinidase deficiency causes dermatological manifestations, seborrheic dermatitis, alopecia etc., isotretinoin side effects in relation to biotinidase activity were studied. Methods: Forty-two (n = 42) patients with severe cystic acne had liver function tests, lipid estimations, serum biotin as well as biotinidase activity evaluations before (value 1) and on the 30th day (value 2) of treatment with isotretinoin monotherapy (Roaccutane 0.5 mg/kg/24 h). The same laboratory tests were evaluated in 50 controls only once. Moreover, the effect of isotretinoin on a known plasma biotinidase activity was evaluated after incubation in vitro with various concentrations of the drug. Results: A statistically significant elevation of liver enzymes and lipids, except high density lipoprotein, was observed at the end of this study. On the contrary, biotinidase activity was found to be significantly decreased as compared to the initial values (value 1 = 4.70 ± 0.89 nmol/min/l, value 2 = 2.50 ± 0.8 nmol/min/l, p < 0.001) and to controls (5.2 ± 0.9 nmol/min/l vs. value 2 = 2.50 ± 0.8 nmol/min/l, p < 0.001). Additionally, biotin levels showed no significant alterations and the in vitro incubation of the enzyme with various concentrations of the drug exhibited no effect on its activity. Conclusion: It is suggested that isotretinoin isomers-metabolites act in the liver, resulting in low biotinidase activity.

Evidence for the participation of the stimulated sympathetic nervous system in the regulation of carnitine blood levels of soccer players during a game

Catecholamines and carnitine blood levels are closely implicated with training. The aim of the study was to investigate the effect of sympathetic nervous system stimulation on carnitine and its fraction levels during training. Blood was obtained from 14 soccer players pregame, at intermission, and postgame. Catecholamines were measured with high-performance liquid chromatography methods; muscle enzymes creatine kinase and lactate dehydrogenase as well as lactate, pyruvate, and total antioxidant status with commercial kits; and carnitine and fraction levels with tandem mass spectrometry. Total antioxidant status (2.97 +/- 0.13 vs 0.96 +/- 0.10 mmol/L, P < .01) as well as free carnitine levels (20.47 +/- 4.0 vs 12.30 +/- 2.8 micromol/L, P < .001) were remarkably decreased especially postgame. Total acylcarnitines (5.20 +/- 1.8 vs 9.42 +/- 3.0 micromol/L, P < .001) and especially total very long-chain acylcarnitines (0.80 +/- 0.01 vs 1.85 +/- 0.03 micromol/L, P < .001) as well as catecholamine levels (adrenaline: 230 +/- 31 vs 890 +/- 110 pmol/L, P < .01; noradrenaline: 1.53 +/- 0.41 vs 3.7 +/- 0.6 nmol/L, P < .01) were significantly increased in players postgame. A statistically significant inverse correlation was found between adrenaline and free carnitine (r = -0.51, P < .01); and a positive correlation was found between adrenaline, total acylcarnitines (r = 0.58, P < .01), and total long-chain acylcarnitine (r = 0.49, P < .01). The significant positive correlation of adrenaline levels with total acylcarnitine and total long-chain acylcarnitine blood levels in athletes as well as the inverse correlation with free carnitine levels may indicate participation of the stimulated sympathetic nervous system in the regulation of some carnitine fraction levels during exercise.

Plasma Leptin Concentrations in Phenylketonuric Patients

High levels of phenylalanine (Phe) in blood have been shown to reduce dopamine (DA) and noradrenaline (NA) production. Leptin levels rise with increasing adiposity in rodents and humans acting as a negative feedback adipostatic signal to brain centers. The aim of this study was to evaluate leptin plasma levels in phenylketonuria (PKU) patients adhering to their special diet and in those on a ‘loose diet’. Forty-nine patients with classical PKU were divided into two groups. Those in group A (n = 21) adhered very strictly to their diet (Phe: 0.15 ± 0.04 mmol/l) and those in group B (n = 28) were on a ‘loose diet’ (Phe: 0.8 ± 0.04 mmol/l). Thirty healthy children of comparable age served as controls. Both patients and controls were in pubertal stage 0 (Tanner). BMI (kg/m2) was evaluated in all the members of the groups. Their daily nutrients were calculated with a 7-day dietary protocol. Leptin was evaluated by RIA, and Phe and Tyrosine with an amino acid autoanalyser. Adrenaline (A), NA and DA were measured by an HPLC method. Plasma leptin in group B patients (28.4 ± 2.0 ng/ml) was significantly increased as compared to group A patients (16.8 ± 2.6 ng/ml) and controls (17.8 ± 3.0 ng/ml; p < 0.001). Plasma DA, A, and NA in group B was lower than in group A and controls. Additionally, leptin negatively correlated with A and DA, whereas Phe positively correlated with the hormone in all groups. Leptin, also, correlated with BMI only in group A and controls. Additionally, the hormone negatively correlated with the total energy intake only in group A (r = –0.43, p < 0.01) and in controls (r = –0.040, p < 0.01). It is suggested that the disregulation of the neuroendocrine system as well as the high Phe blood levels might play an important role in the increased leptin concentrations in PKU patients on a ‘loose diet’.

The effect of the mode of delivery on maternal-neonatal interleukin-6, biogenic amine and their precursor amino acid concentrations.

Abstract Background: Biogenic amine, adrenaline, noradrenaline, dopamine and 5-hydroxy-tryptamine (5-HT) levels are related to interleukin-6 (IL-6) plasma concentrations and endurance exercise. The aim of our study was to investigate the effect of the mode of delivery on maternal-neonatal IL-6, biogenic amine and their precursor amino acid levels. Methods: Some women with normal pregnancy (n=56) were divided into two groups: group A (n=26) with normal labor and vaginal delivery, and group B (n=30) with scheduled cesarean section. Blood was obtained from the mothers at the beginning of labor and immediately after delivery (pre- vs. post-delivery), as well as from the umbilical cord (CB). Total antioxidant status (TAS) and IL-6 levels were measured with commercial kits, the precursor amino acids, tyrosine and tryptophan with tandem mass spectrometry and the biogenic amine blood levels with HPLC methods, respectively. Results: TAS, IL-6, biogenic amine and their precursor amino acid blood levels were similar in the two groups of mothers pre-delivery. TAS levels were reduced, whereas the amino acids, the catecholamine, 5-HT and IL-6 levels were increased post-delivery and in the CB of group A and unaltered in group B at the same time of the study. Conclusions: During a vaginal delivery process, the low TAS, the increased levels of the studied amino acids, the catecholamines, 5-HT and IL-6 may be due to the activation of the neuroendocrine system and the participation of skeletal and uterine muscles. The mode of delivery may be taken into account when IL-6 plasma levels are evaluated as an anti-inflammatory index perinatally. Clin Chem Lab Med 2008;46:1624–30.

The effect of the mode of delivery on the maternal-neonatal carnitine blood levels and antioxidant status

Abstract Background: Carnitine blood levels are closely related to β-oxidation and implicated with strenuous muscle contractions. Normal delivery process is characterized by the participation of the uterus and most skeletal muscles. Methods: Women with normal pregnancy (n=56) were divided into two groups. Group A (n=26) with normal labor and vaginal delivery and group B (n=30) with scheduled cesarean section. Blood was obtained from the mothers at the beginning of labor and immediately after delivery (pre- vs. post-delivery), as well as from the cord blood (CB). Total antioxidant status (TAS) was measured with a commercial kit and carnitine was measured in blood spots on Guthrie cards with tandem-mass spectrometry. Results: TAS and carnitine levels were similar in all the groups pre-delivery. In contrast, TAS and carnitine levels were significantly lower in group A than in group B post-delivery. Remarkably lower TAS and carnitine levels were measured in the CB of neonates of group A as compared to the CB of neonates of group B. Conclusions: The lower TAS and carnitine levels measured in group A as compared to group B post-delivery may be due to uterus and skeletal muscle contraction during a normal labor process. Infants born with scheduled cesarean section are benefited with high carnitine levels to face oxidation perinatally. Clin Chem Lab Med 2008;46:680–6.

Haemostatic variables in phenylketonuric children under dietary treatment

SummaryClassical phenylketonuria (PKU) (McKusick 261600) is an inborn error of metabolism treated by a controlled low-phenylalanine (Phe) diet started as soon as possible in the first days of life. Such a diet can be achieved with vegetable protein and can be considered non-atherogenic because of the reduction of animal products. Thirty patients with PKU were classified into two groups according to their annual mean Phe levels. Their daily protein intake was largely replaced by PKU2 Milupa which contains a mixture of amino acids. The product has no phenylalanine or fat of any kind. Thirty-eight (38) individuals of comparable age were used as controls. Group A (n=15) had good compliance with the special diet (Phe mean 192±115 µmol/L); group B (n=15) did not strictly adhere to the diet (Phe mean 595±263 µmol/L). Certain haemostatic components (factors I, VII, VIII, and X, antithrombin III, protein C, and plasminogen) and lipid variables (cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, very-low-density lipoprotein) as well as Phe levels were estimated. All the haemostatic factors studied were found within the normal range with the exception of a significant reduction in protein C in both groups of PKU patients. Furthermore, a statistically significant reduction in factor VII and X concentrations was observed in patients on strict diet. Cholesterol and low-density lipoprotein concentrations were significantly lower in PKU children compared to normal controls. It is suggested that even though the special diet of PKU children, especially in group A, is rich in vegetables, the reduced fat intake might have impaired the absorption of vitamin K and its delivery to the site of synthesis of vitamin K-dependent haemostatic factors.

The effect of diet on Paraoxonase 1/Arylesterase activities in patients with disorders of galactose metabolism.

Objective  To investigate the effects of diet on the antiatherogenic enzyme Paraoxonase 1/Arylesterase (PON1/Aryl) activities in patients with disorders of galactose metabolism.

Biotin recycling impairment in phenylketonuric children with seborrheic dermatitis

Objective To investigate the effect of a therapeutic diet on serum biotin levels and to explain the seborrheic dermatitis in phenylketonuric (PKU) patients on a “loose” diet.