Supplementation with a powdered blend of PUFAs normalizes DHA and AA levels in patients with PKU

Plasma Phospholipidomic Profile Differs between Children with Phenylketonuria and Healthy Children

Phenylketonuria (PKU) is a disease of the catabolism of phenylalanine (Phe), caused by an impaired function of the enzyme phenylalanine hydroxylase. Therapeutics is based on the restriction of Phe intake, which mostly requires a modification of the diet. Dietary restrictions can lead to imbalances in specific nutrients, including lipids. In the present study, the plasma phospholipidome of PKU and healthy children (CT) was analyzed by hydrophilic interaction liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. Using this approach, 187 lipid species belonging to nine different phospholipid classes and three ceramides were identified. Principal component analysis of the lipid species data set showed a distinction between PKU and CT groups. Univariate analysis revealed that 146 species of phospholipids were significantly different between both groups. Lipid species showing significant variation included phosphatidylcholines, containing polyunsaturated fatty acids (PUFA), which were more abundant in PKU. The high level of PUFA-containing lipid species in children with PKU may be related to a diet supplemented with PUFA. This study was the first report comparing the plasma polar lipidome of PKU and healthy children, highlighting that the phospholipidome of PKU children is significantly altered compared to CT. However, further studies with larger cohorts are needed to clarify whether these changes are specific to phenylketonuric children.

Effect of fasting status and other pre-analytical variables on quantitation of long-chain fatty acids in red blood cells

Long-chain fatty acids (LCFAs), including omega-3 and omega-6 fatty acids, play essential roles in health maintenance and outcomes. Insufficient intake or the inability to absorb LCFAs from the diet can cause a number of health problems. Evaluation of fatty acid profiles in plasma, serum or red blood cells (RBCs) is routinely used to monitor patients at risk of developing deficiency. Quantitation of LCFAs in RBCs offers advantages over serum/plasma due to low intra-individual variability. Fatty acid composition in RBCs also reflects long-term dietary intake, providing additional information about the patient's nutritional status. However, the literature does not currently address the impact of pre-analytical factors (conditions of RBC collection, sample handling and short-term storage) on LCFA measurements. This study evaluated the effect of several anticoagulants, interferents, different storage conditions and fasting status on quantitation of the twenty-one most abundant LCFAs in RBCs by gas chromatography negative chemical ionization-mass spectrometry (GCNCI-MS). LCFA results were assessed quantitatively (nmol/mL) or as a percent of total. Most common tube types (containing citrate, sodium heparin or EDTA) were all appropriate for blood collection. Whole blood and lysed RBCs were stable at least 24 h at room temperature and up to 7 days refrigerated. Lysed RBCs were also stable for up to three freeze/thaw cycles. The presence of icterus or lipemia did not affect results. LCFAs concentrations in RBCs did not change ~4 h after high-fat intake when the lipid concentration in circulation reaches a peak, while plasma levels of most fatty acids increased up to 40% in response. In summary, RBCs are a reliable sample type for LCFA quantitation in the clinical laboratory. In contrast to plasma or serum, RBCs isolated from non-fasting, hemolyzed or lipemic whole blood specimens are all acceptable for testing. Therefore, RBCs might be a preferable sample type for evaluation of nutritional status of young pediatric patients and in patients with conditions associated with hemolytic anemia or hyperlipidemia.

Effects of omega-3 fatty acids supplementation on inflammatory parameters after chronic administration of L-tyrosine

Tyrosinemia type II is an autosomal recessive inborn error of metabolism caused by hepatic cytosolic tyrosine aminotransferase deficiency. Importantly, this disease is associated with neurological and developmental abnormalities in many patients. Considering that the mechanisms underlying neurological dysfunction in hypertyrosinemic patients are poorly understood, in the present work we investigated the levels of cytokines - tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-10 - in cerebellum, hippocampus, striatum of young rats exposed to chronic administration of L-tyrosine. In addition, we also investigated the impact of the supplementation with Omega-3 fatty acids (n-3 PUFA) on the rodent model of Tyrosinemia. Notably, previous study demonstrated an association between L-tyrosine toxicity and n-3 PUFA deficiency. Our results showed a significant increase in the levels of pro- and anti-inflammatory cytokines in brain structures when animals were administered with L-tyrosine. Cerebral cortex and striatum seem to be more susceptible to the inflammation induced by tyrosine toxicity. Importantly, n-3 PUFA supplementation attenuated the alterations on cytokines levels induced by tyrosine exposure in brain regions of infant rats. In conclusion, the brain inflammation is also an important process related to tyrosine neurotoxicity observed in the experimental model of Tyrosinemia. Finally, n-3 PUFA supplementation could be considered as a potential neuroprotective adjunctive therapy for Tyrosinemias, especially type II.

Body Composition and Circulating Polyunsaturated Fatty Acids at Age 6 Years: A Longitudinal Pilot Study

Maternal polyunsaturated fatty acid (PUFA) status during pregnancy may influence birth outcomes and offspring adiposity during childhood. Cord blood PUFA levels associate positively with maternal PUFA and negatively with the newborn's abdominal adiposity. However, longitudinal, prospective studies consistently evaluating maternal and cord blood and PUFA levels in childhood and their association with the child's body composition are so far lacking. In a population of 16 apparently healthy children born appropriate for gestational age and followed longitudinally since birth, we assessed circulating PUFA (by gas chromatography) in maternal, cord, and peripheral blood at age 6 years and studied their correlation with body composition (by absorptiometry) and endocrine-metabolic variables at age 6 years. No associations were found among parameters of body composition and endocrine-metabolic variables at age 6 years and maternal, cord blood or circulating PUFA in peripheral blood. Maternal levels of n-6 linoleic acid, total n-6, and the ratio of n-6:n-3 correlated with their corresponding PUFA levels at age 6 years. In conclusion, in this pilot study, maternal, cord blood, and children's circulating PUFA do not appear to have an impact on body composition and endocrine-metabolic status at the age of 6 years. The close association between maternal PUFA and offspring PUFA at that age may reflect a similarity in nutritional habits in the mother and child.

Omega-3 fatty acid supplementation can prevent changes in mitochondrial energy metabolism and oxidative stress caused by chronic administration of L-tyrosine in the brain of rats

Deficiency of hepatic enzyme tyrosine aminotransferase characterizes the innate error of autosomal recessive disease Tyrosinemia Type II. Patients may develop neurological and developmental difficulties due to high levels of the amino acid tyrosine in the body. Mechanisms underlying the neurological dysfunction in patients are poorly known. Importantly, Tyrosinemia patients have deficient Omega-3 fatty acids (n-3 PUFA). Here, we investigated the possible neuroprotective effect of the treatment with n-3 PUFA in the alterations caused by chronic administration of L-tyrosine on important parameters of energetic metabolism and oxidative stress in the hippocampus, striatum and cerebral cortex of developing rats. Chronic administration of L-tyrosine causes a decrease in the citrate synthase (CS) activity in the hippocampus and cerebral cortex, as well as in the succinate dehydrogenase (SDH) and isocitrate dehydrogenase (IDH) activities, and an increase in the α-ketoglutarate dehydrogenase activity in the hippocampus. Moreover, in the striatum, L-tyrosine administration caused a decrease in the activities of CS, SDH, creatine kinase, and complexes I, II-III and IV of the mitochondrial respiratory chain. We also observed that the high levels of L-tyrosine are related to oxidative stress in the brain. Notably, supplementation of n-3 PUFA prevented the majority of the modifications caused by the chronic administration of L-tyrosine in the cerebral enzyme activities, as well as ameliorated the oxidative stress in the brain regions of rats. These results indicate a possible neuroprotective and antioxidant role for n-3 PUFA and may represent a new therapeutic approach and potential adjuvant therapy to Tyrosinemia Type II individuals.

Modulation of Adipocyte Differentiation and Proadipogenic Gene Expression by Sulforaphane, Genistein, and Docosahexaenoic Acid as a First Step to Counteract Obesity

Obesity is characterized by excess body fat accumulation due to an increase in the size and number of differentiated mature adipocytes. Adipocyte differentiation is regulated by genetic and environmental factors, and its inhibition could represent a strategy for obesity prevention and treatment. The current study was designed with two aims: (i) to evaluate the changes in the expression of adipogenic markers (C/EBPα, PPARγ variant 1 and variant 2, and GLUT4) in 3T3-L1 murine preadipocytes at four stages of the differentiation process and (ii) to compare the effectiveness of sulforaphane, genistein, and docosahexaenoic acid in reducing lipid accumulation and modulating C/EBPα, PPARγ1, PPARγ2, and GLUT4 mRNA expression in mature adipocytes. All bioactive compounds were shown to suppress adipocyte differentiation, although with different effectiveness. These results set the stage for further studies considering natural food constituents as important agents in preventing or treating obesity.

Metabolomic Insights into the Nutritional Status of Adults and Adolescents with Phenylketonuria Consuming a Low-Phenylalanine Diet in Combination with Amino Acid and Glycomacropeptide Medical Foods

BACKGROUND

Nutrient status in phenylketonuria (PKU) requires surveillance due to the restrictive low-Phe diet in combination with amino acid medical foods (AA-MF) or glycomacropeptide medical foods (GMP-MF). Micronutrient profiles of medical foods are diverse, and optimal micronutrient supplementation in PKU has not been established.

METHODS

In a crossover design, 30 participants with PKU were randomized to consume AA-MF and Glytactin™ GMP-MF in combination with a low-Phe diet for 3 weeks each. Fasting venipunctures, medical food logs, and 3-day food records were obtained. Metabolomic analyses were completed in plasma and urine by Metabolon, Inc.

RESULTS

The low-Phe diets in combination with AA-MF and GMP-MF were generally adequate based on Dietary Reference Intakes, clinical measures, and metabolomics. Without micronutrient supplementation of medical foods, >70% of participants would have inadequate intakes for 11 micronutrients. Despite micronutrient supplementation of medical foods, inadequate intakes of potassium in 93% of participants and choline in >40% and excessive intakes of sodium in >63% of participants and folic acid in >27% were observed. Sugar intake was excessive and provided 27% of energy.

CONCLUSIONS

Nutrient status was similar with AA-MF and Glytactin GMP-MF. More research related to micronutrient supplementation of medical foods for the management of PKU is needed.

Is cytotoxicity a determinant of the different in vitro and in vivo effects of bioactives?

BACKGROUND

Foodstuffs of both plant and animal origin contain a wide range of bioactive compounds. Although human intervention studies are mandatory to assess the health effects of bioactives, the in vitro approach is often used to select the most promising molecules to be studied in vivo. To avoid misleading results, concentration and chemical form, exposure time, and potential cytotoxicity of the tested bioactives should be carefully set prior to any other experiments.

METHODS

In this study the possible cytotoxicity of different bioactives (docosahexaenoic acid, propionate, cyanidin-3-O-glucoside, protocatechuic acid), was investigated in HepG2 cells using different methods. Bioactives were supplemented to cells at different concentrations within the physiological range in human blood, alone or in combination, considering two different exposure times.

RESULTS

Reported data clearly evidence that in vitro cytotoxicity is tightly related to the exposure time, and it varies among bioactives, which could exert a cytotoxic effect even at a concentration within the in vivo physiological blood concentration range. Furthermore, co-supplementation of different bioactives can increase the cytotoxic effect.

CONCLUSIONS

Our results underline the importance of in vitro cytotoxicity screening that should be considered mandatory before performing studies aimed to evaluate the effect of bioactives on other cellular parameters. Although this study is far from the demonstration of a toxic effect of the tested bioactives when administered to humans, it represents a starting point for future research aimed at verifying the existence of a potential hazard due to the wide use of high doses of multiple bioactives.

Newborns with lower levels of circulating polyunsaturated fatty acids (PUFA) are abdominally more adipose

BACKGROUND

Maternal nutrition is the main source of Poly-Unsaturated Fatty Acids (PUFA) for the fetus. PUFA may influence the accumulation of fat in early life.

OBJECTIVES & METHODS

In 33 breastfed infants born appropriate-for-gestational-age, we studied whether body composition (judged by absorptiometry at 2 wk and 4 mo) relates to PUFA levels (assessed by gas chromatography) in the maternal or fetal circulation at birth.

RESULTS

Abdominal fat at 2 wk associated negatively to umbilical-cord levels of separate PUFA (linoleic, arachidonic, eicosapentanoic and docosahexaenoic acid; all P between 0.001 and 0.015). Collectively, the assessed n-6 PUFA on one hand and the n-3 PUFA on the other hand associated negatively to the absolute amount of abdominal fat (in grams; P = 0.001 and P = 0.002, respectively) and to the relative amount of abdominal fat (fraction of total fat; P = 0.001 and P = 0.006, respectively). No other significant associations were observed.

CONCLUSION

In conclusion, newborns with lower levels of circulating PUFA were found to be abdominally more adipose. The mechanisms underpinning these associations remain to be determined.