José Angel Prieto

Persistence of essential fatty acid deficiency in cystic fibrosis despite nutritional therapy.

To study the evolution of plasma fatty acid composition of patients with cystic fibrosis (CF) in relation to nutritional status, pancreatic function, and development of CF-related liver disease (CFRLD) and diabetes mellitus, 24 CF pediatric patients with stable pulmonary disease were studied before and after an approximate period of 8 y. Nutritional status, pulmonary function, pancreatic function, and presence of CFRLD or diabetes mellitus were recorded. Results were compared with data obtained in 83 healthy children. Patients with CF have significantly lower linoleic acid (LA), docosahexaenoic acid (DHA), lignoceric acid, and LA × DHA product and higher oleic acid, mead acid, dihomo-γ-linoleic acid, and docosapentaenoic acid (DPA). Comparison of samples taken at first and second studies revealed a significant decrease in LA levels and lignoceric acid associated with a significant increase in dihomo-γ-linoleic acid levels. Patients with CFRLD showed significantly higher mead acid/arachidonic acid ratio and lower total ω6 polyunsaturated fatty acids content. There was no relation of plasma fatty acids composition with pancreatic function, pulmonary function, or diabetes mellitus. Follow-up of patients with CF shows that essential fatty acids deficiency, particularly in LA and DHA content, persisted unmodified along time despite an adequate nutritional therapy. Future studies after supplementation with ω3 polyunsaturated fatty acids should be undertaken.

Fatty acid deficiency profile in children with food allergy managed with elimination diets

Aim: To evaluate plasma fatty acid (FA) composition of children with food allergy undergoing elimination diets that avoided the offending antigens.

Fatty acid profile in patients with phenylketonuria and its relationship with bone mineral density

BackgroundPatients with phenylketonuria (PKU) undergo a restrictive vegan-like diet, with almost total absence of n-3 fatty acids, which have been proposed as potential contributors to bone formation in the healthy population. The PKU diet might lead these patients to bone mass loss and, consequently, to the development of osteopenia/osteoporosis. Therefore, we proposed to analyze their plasma fatty acid profile status and its relationship with bone health.MethodsWe recruited 47 PKU patients for this cross-sectional study and divided the cohort into three age groups (6–10 years, 11–18 years, 19–42 years). We measured their plasma fatty acid profile and bone mineral density (BMD) (both at the femoral neck and the lumbar spine). Seventy-seven healthy controls also participated as reference values of plasma fatty acids.ResultsDocosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and total n-3 fatty acids were significantly diminished in PKU patients compared with healthy controls. DHA, EPA, and total n-3 fatty acids were also positively associated with bone mineral density (r = 0.83, p = 0.010; r = 0.57, p = 0.006; r = 0.73, p = 0.040, respectively). There was no association between phenylalanine (Phe), Index of Dietary Control (IDC), calcium, 25-hydroxivitamin D concentrations, daily calcium intake, and BMD.ConclusionOur results suggest a possible influence of essential fatty acids over BMD in PKU patients. The lack of essential n-3 fatty acids intake in the PKU diet might affect bone mineralization. Further clinical trials are needed to confirm the effect of the n-3 essential fatty acids on bone accrual in a cohort of PKU patients.

Arachidonic acid content in adipose tissue is associated with insulin resistance in healthy children.

Background: The fatty acid composition of membrane structural lipids, which is partly dependent on dietary intake, is associated with insulin action. Aim: To examine the association between fatty acid composition of adipose tissue and skeletal muscle phospholipids with insulin resistance markers in a healthy pediatric population. Methods: Using a cross-sectional design, we studied 83 healthy children divided into 3 groups, ages 2 to 5, 6 to 10 and more than 10 years. Measurements: Fatty acid composition of adipose tissue triacylglycerols and skeletal muscle phospholipids, plasma lipid profile and fasting plasma levels of glucose and insulin were measured. Results: There was a linear increase of insulinemia, glycemia and homeostasis adipose tissue model assessment (HOMA) index throughout the pediatric age range. Linoleic acid proportion in skeletal muscle and arachidonic acid proportion in adipose tissue also increased significantly with age. An age-independent positive correlation between insulinemia or HOMA index and arachidonic acid content in adipose tissue triacylglycerols (r = 0.47, P < 0.001) was found. An age-dependent negative correlation was present between insulinemia or HOMA index and oleic acid content in skeletal muscle phospholipids (r = −0.30, P = 0.03 and r = −0.28, P < 0.04, respectively). Trans fatty acids content did not correlate with any marker of insulin resistance. Conclusion: Healthy children present a prepubertal increase of insulin resistance, which is significantly correlated with arachidonic acid content in adipose tissue.

Determination of creatine and guanidinoacetate by GC-MS: Study of their stability in urine at different temperatures

OBJECTIVES Evaluation of a GC-MS method using N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) as the silylating agent for GC-MS. Study of the stability of creatine and guanidinoacetate in urine. DESIGN AND METHODS 22 urines were kept at RT, 4 degrees C and -30 degrees C for 15 days. RESULTS MTBSTFA produces a single chromatographic peak in contrast with other derivatizing agents. Creatine concentration increases at room temperature (326% on average), and at 4 degrees C (75%). However, detection decreases after freezing (-37%). Guanidinoacetate is stable, but decreases after freezing (-37%). Sonication before analysis is crucial to obtain repetitive results. CONCLUSIONS A modified GC-MS method has been validated and the conditions for preservation of the urine have been established.

Fatty acid composition of skeletal muscle and adipose tissue in Spanish infants and children

There is a relationship between the fatty acid profile in skeletal muscle phospholipids and peripheral resistance to insulin in adults, but similar data have not been reported in infancy and childhood. The objective of this study was to investigate the fatty acid composition of skeletal muscle and adipose tissue across the paediatric age range. The fatty acid profile of skeletal muscle phospholipids and adipose tissue triacylglycerols was analysed in ninety-three healthy Spanish infants and children distributed into four groups: group 1 (0 to <2 years, n 10); group 2 (2 to <5 years, n 41); group 3 (5 to <10 years, n 24); group 4 (10 to 15 years, n 18). In skeletal muscle phospholipids, oleic acid (18: 1n-9cis) content decreased significantly whereas that of linoleic (18: 2n-6) acid increased significantly with age (P for trend <0.01). In adipose tissue, the contents of triacylglycerol and linoleic acid increased significantly across the paediatric age range (P for trend <0.01), whereas dihomo-gamma-linolenic (20: 3n-6) and arachidonic (20: 4n-6) showed significant differences between groups. The variations in fatty acid composition observed with age indicated an imbalance in dietary n-3/n-6 long-chain PUFA.

The Arginine-Creatine Pathway is Disturbed in Children and Adolescents With Renal Transplants

Cardiovascular disease is an important cause of morbidity in recipients of renal transplants. The aim of the present study was to analyze the status of the arginine-creatine pathway in such patients, given the relationship between the arginine metabolism and both renal function and the methionine-homocysteine cycle. Twenty-nine children and adolescents (median age 13, range 6–18 years), who had received a renal allograft 14.5–82.0 months before, were recruited for the study. On immunosuppressive therapy, all patients evidenced an adequate level of renal function. Plasma concentrations of homocysteine and glycine were significantly higher, whereas urinary excretions of guanidinoacetate and creatine were significantly lower than controls. Urinary excretions of guanidinoacetate and creatine correlated positively with creatinine clearance. Urinary excretion of creatine was negatively correlated with plasma concentration of homocysteine. The demonstration of disturbances in the arginine-creatine pathway in patients with well-functioning renal transplants and in absence of chronic renal failure represents a novel finding. We speculate that the low urinary excretion of guanidinoacetate and creatine is probably related to the nephrotoxic effect of immunosuppressive therapy and to defective methylation associated with the presence of hyperhomocysteinemia.

Abnormalities in plasma fatty acid composition in human immunodeficiency virus-infected children treated with protease inhibitors.

AIM To study plasma fatty acid composition in human immunodeficiency virus-infected children treated with protease inhibitors and its relation with other components of the metabolic syndrome observed after this therapy. DESIGN Cross-sectional study from collected clinical database. SUBJECTS 17 children with HIV infection treated with protease inhibitors. Nine patients received ritonavir (20-30 mg/kg/d) and the remaining eight received nelfinavir (60-90 mg/kg/d). Duration of protease inhibitors treatment was 711+/-208 d. As controls, we used 112 matched blood samples from apparently healthy children admitted for minor surgical procedures. METHODS Plasma fatty acids were determined using a Hewlett Packard GC 5890 gas chromatograph. RESULTS Plasma levels of cholesterol and triglycerides and insulin-like growth factor 1 (IGF-1) tended to be high in protease inhibitor-treated patients. Plasma content of omega6 long-chain polyunsaturated fatty acids and, in particular, of the highly unsaturated 22ratio4omega6 and 22ratio5omega6, was significantly increased. Also, infected children had increased Delta6 and Delta4 desaturase activities and decreased Delta5 desaturase activity. Significant correlations were present between plasma IGF-1 level and plasma triglycerides, plasminogen activator inhibitor-1 activity and Delta6 desaturase activity. CONCLUSION HIV-infected, protease inhibitor-treated children exhibit a metabolic syndrome which is associated with significant changes in plasma fatty acid composition. These changes are similar to those observed in situations of insulin resistance and are linked to variations in plasma IGF-1 concentration.

Comparison of plasma and dry blood spots as samples for the determination of nitisinone (NTBC) by high-performance liquid chromatography-tandem mass spectrometry. Study of the stability of the samples at different temperatures

UNLABELLED Tyrosinemia is an inborn error of metabolism characterized by the accumulation of tyrosine as well as toxic by-products. NTBC or nitisinone is a drug currently used for the treatment of tyrosinemia that avoids the formation of these toxic substances. This paper presents the determination of NTBC in plasma and dry blood spots by high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry. The concentration of NTBC in matched plasma-dry blood spots was compared and the study of degradation of NTBC in plasma and dry spots at different temperatures is presented. METHOD For sample preparation, plasma proteins were precipitated with acetonitrile and 3-mm discs were extracted with methanol. ESI(+) was used as inozation method and the analytes were detected by multiple reaction monitoring using the transitions 330>218 for NTBC and 340>228 for mesotrione, used as internal standard. RESULTS There is good correlation between concentrations obtained in dry blood spots and plasma (r(2)=0.83), although values are 2.4 times higher in plasma samples. NTBC in plasma is stable at least for 45 days frozen at -30°C and refrigerated at 4°C. However, it shows slow decomposition at room temperature, approximately 30% after 45 days. The method shows good precision, accuracy and linearity and the detection limit is 50 nmol/L and paper samples are appropriate for the monitorization of NTBC.

Effect of docosahexaenoic acid administration on plasma lipid profile and metabolic parameters of children with methylmalonic acidaemia

SummaryAim. To evaluate the effect of administration of docosahexaenoic acid (DHA) on dyslipidaemia, plasma fatty acid composition and metabolic parameters of children with isolated methylmalonic acidaemia (MMA) (McKusick 25100).Methods. Four children (3 male, 1 female) with MMA (mut(0)), participated in a crossover, randomized study of DHA administration (25 mg/kg per day, divided into three daily doses). The control group comprised 56 healthy children, aged 10± 2.7 years, (51 male, 5 female), who were followed in our clinic owing to possible familial risk of cardiovascular disease.Results. The comparison of plasma fatty acid composition of children with MMA versus control children demonstrated that the patients had significantly higher values for oleic acid (p = 0.004) and linolenic acid (p = 0.008). No differences were observed in the levels of DHA and arachidonic acid. Plasma concentrations of insulin, glycine, ammonia, total cholesterol and cholesterol fractions did not change with DHA administration. No significant changes were observed in urinary excretion of methylmalonic acid. As expected, the percentage of DHA and n−3 fatty acids in plasma increased significantly after therapy (p = 0.005 and 0.014, respectively). The most remarkable result was a decrease of plasma levels of triglycerides after DHA therapy (p = 0.014).Conclusion. As previously found in normal children, dietary supplementation with DHA decreases the triglyceride levels, normalizing the hypertriglyceridaemia of these children without any evidence of short-term adverse effects.