Lipid changes in the metabolome of a single case study with maple syrup urine disease (MSUD) after five days of improved diet adherence of controlled branched-chain amino acids (BCAA).

BACKGROUND: Distinguishing systemic metabolic disruptions in maple syrup urine disease (MSUD) beyond amino acid pathways is under-investigated, yet important to understanding disease pathology and treatment options. METHODS: An adolescent female (15 years) with MSUD without liver transplant, attended 2 study visits, 5 days apart. Medical diet adherence was determined based on her 3-day diet records and plasma branched-chain amino acid (BCAA) concentrations at both study visits. Plasma from a single age- and sex-matched control (MURDOCK Study, Duke University) and the case patient were analyzed with UPLC/MS/MS for intensity (m/z), annotated, and normalized against a median of 1 (Metabolon, Morrisville NC). Differences between case/control and 5-day comparisons were defined as ≥ Ç€ 0.5 ǀ. RESULTS: 434 lipid metabolites were identified across samples; 90 (20.7%) were higher and 120 (27.6%) lower in the MSUD case at baseline compared with control. By study visit 2, plasma BCAA had declined, while 48 (53%) of elevated lipids and 14 (11.7%) of lower lipid values had moved to within ǀ 0.5 ǀ of control. Most shifts towards control by day 5 were seen in long-chain fatty acid intermediates (42%) and acylcarnitines (32%). Although androgenic (28%) and bile acid (23%) metabolites increased towards control, neither reached control level by day 5. DISCUSSION: This comparative metabolomics study in a single MSUD case and healthy control suggests intrinsic differences in MSUD lipid metabolism potentially influenced by therapeutic diet. Findings suggest influences on hormone regulation, fatty acid oxidation, and bile acid synthesis, but further studies are needed to confirm an association between MSUD and lipid dysregulation. SYNOPSIS: Within 5 days of improved dietary adherence, a single MSUD case experienced substantial changes in lipid markers potentially related to changes in plasma branched-chain amino acids.

Large neutral amino acid status in association with P:T ratio and diet in adult and pediatric patients with phenylketonuria.

BACKGROUND: Intake of large neutral amino acids (LNAA) may inhibit phenylalanine (PHE) transport across the blood brain barrier and assist with blood PHE control in patients with phenylketonuria (PKU). We evaluated the interrelationship between LNAA in plasma and diet on Phe:Tyr (P:T) ratio in patients with PKU and the influence of dietary factors on plasma LNAA markers. METHODS: Plasma amino acid values and 3-day food record analysis from two studies (34 male/30 female; age 4.6-47 years) were examined. For pediatrics (<18 years) and adults (≥18 years) the relationship between P:T ratio, plasma LNAA, and dietary intake patterns were investigated. RESULTS: Dietary factors influencing P:T ratio included intake of total protein (g/kg), medical food (MF) protein (g/kg, % below Rx), and LNAA (g) in the full cohort (P < .05). Associations were found between plasma valine and other dietary and plasma LNAA in pediatrics (P < .05) and plasma LNAA with dietary LNAA intake in adults (P = .019). Plasma P:T ratio was inversely associated with plasma LNAA concentrations in both age groups (P < .05). Aside from histidine in pediatrics (P = .024), plasma LNAA did not differ by having plasma PHE levels within or above the therapeutic range (120-360 µmol/L). Plasma LNAA in both age groups was similar to reported healthy control values. CONCLUSION: P:T ratio is significantly tied to dietary LNAA, adherence to MF Rx, and plasma LNAA concentrations. Additionally, P:T ratio and valine may be effective clinical proxies for determining LNAA metabolic balance and LNAA quality of the diet in patients with PKU.

One-year follow-up of B vitamin and Iron status in patients with phenylketonuria provided tetrahydrobiopterin (BH4).

BACKGROUND: People with Phenylketonuria (PKU) who respond to tetrahydrobiopterin (BH4) often decrease dependence on medical food (MF) following increased phenylalanine (phe) tolerance. Responders to BH4 may experience a reduction in certain nutrients if not compensated through intact foods or supplements. This study investigated B6, B12, folate, and iron status based on blood levels and dietary intake in patients with PKU responsive to BH4 over 1 year. METHODS: Fifty-eight patients with PKU, ages 4-50 years were recruited and initiated on BH4 therapy. Patients were monitored for BH4 response, and nutritional status was recorded at regular intervals over 12 months. The analysis included 33 patients with known BH4 response status and complete nutritional data. Nutrient intake was determined by National Data System for Research (NDSR) analysis of self reported 3 day diet records and compared to Dietary Reference Intakes (DRIs). Blood biomarkers were analyzed by Quest Diagnostics and compared to laboratory reference ranges. Patient laboratory values were compared to controls from the National Health and Examination Survey (NHANES). Differences in nutrient intakes across time points were examined, stratified by age, using nonparametric methods. Statistical analyses were completed with SAS 9.4, with significance set at α = 0.05. RESULTS: Medical food intake declined among pediatric (p < 0.01) and adult (p = 0.06) BH4 responders over 1 year. Among those < 18 years of age, mean percent of calories obtained from MF declined from 21.3 to 4.7%. In adults, percent calories from MF dropped from 19.5 to 4.0%. Though maintaining laboratory and dietary values within reference ranges, responders < 18 years experienced a significant decline in serum B12 (p = 0.01), dietary folate (p = 0.006), and dietary iron (p = 0.004) over the study. CONCLUSION: Although mean dietary and laboratory values for B12, B6, folate, and iron in BH4 responders and non-responders were adequate at baseline and 12-month follow-up, responders experienced a significant decline in serum B12 over 1 year, which may be explained by decreased intake of fortified MF. Both response groups had lower serum B12 than NHANES controls at baseline and 12 months. Results indicate a need to monitor B12 concentrations and consider micronutrient supplementation, with special attention to pediatric patients with PKU.

Protein intake and physical activity are associated with body composition in individuals with phenylalanine hydroxylase deficiency.

OBJECTIVE: Determine whether body composition as it relates to dietary protein in patients with phenylalanine hydroxylase (PAH) deficiency is associated with genotype, dietary factors, and lifestyle choices. METHODS: We examined associations between protein intake (intact and medical foods: MF) and body composition in PAH-deficient patients along with, physical activity, and genotype. Protein intakes (total, intact, and MF) were analysed from three-day food records with Nutrition Data System for Research (NDSR) in 59 children and 27 adults (N=86, median age=16.0years). The severity of PAH deficiency was classified using the genotype assigned value method (AV sum). Physical activity was assessed using a study-developed question (light vs. intense activity). Body composition was measured by DXA, including android:gynoid ratio (A:G), fat-free mass index (FFMI), fat mass index (FMI), and FMI:FFMI ratio. RESULTS: High intact protein intake was associated with high FFMI (rs=0.75, p=0.008) and low FMI:FFMI (rs=-0.59, p=0.04) in adults. Only in children, MF protein (rs=0.38, p=0.04) was directly proportional to FFMI. Median intact protein intakes of adults (25.1 vs. 9.9g/d, p<0.001) and children (11 vs. 6g/d, p<0.001) were higher than prescribed. Only in adults, the actual median MF protein intake was lower than prescribed (53 vs. 60g/d, p=0.03). In adults and children, light activity was associated with higher fat mass indices compared to intense activity (adults: FMI:FFMI: ß=1.1, p=0.001, children: FMI:FFMI: ß=1.1, p=0.007; FMI ß=2.1, p=0.01; A:G ß=1.1, p=0.04). All associations remained significant after covariate adjustment. Genotype was not associated with body composition. CONCLUSIONS: Although fat-free mass in adults was positively associated with intact protein intake, it should be consumed as prescribed per individual tolerance to maintain plasma Phe concentrations within treatment range. In children, total protein maximized with MF should be encouraged to promote lean mass. Nutrition counselling could be complemented with physical activity recommendations for optimal clinical outcomes.

Updated, web-based nutrition management guideline for PKU: An evidence and consensus based approach.

BACKGROUND: In 2014, recommendations for the nutrition management of phenylalanine hydroxylase deficiency were published as a companion to the concurrently published American College of Medical Genetics and Genomics guideline for the medical treatment of phenylketonuria (PKU). These were developed primarily from a summary of findings from the PKU scientific review conference sponsored by the National Institutes of Health and Agency for Healthcare Research & Quality along with additional systematic literature review. Since that time, the Genetic Metabolic Dietitians International and the Southeast Regional Newborn Screening and Genetics Collaborative have partnered to create a web-based technology platform for the update and development of nutrition management guidelines for inherited metabolic disorders. OBJECTIVE: The purpose of this PKU guideline is to establish harmonization in treatment and monitoring, to guide the integration of nutrition therapy in the medical management of PKU, and to improve outcomes (nutritional, cognitive, and developmental) for individuals with PKU in all life stages while reducing associated medical, educational, and social costs. METHODS: Six research questions critical to PKU nutrition management were formulated to support guideline development: Review, critical appraisal, and abstraction of peer-reviewed studies and unpublished practice literature, along with expert Delphi survey feedback, nominal group process, and external review from metabolic physicians and dietitians were utilized for development of recommendations relevant to each question. Recommendations address nutrient intake, including updated protein requirements, optimal blood phenylalanine concentrations, nutrition interventions, monitoring parameters specific to life stages, adjunct therapies, and pregnancy and lactation. Recommendations were graded using a rigorous system derived from the Academy of Nutrition and Dietetics. RESULTS AND CONCLUSION: These guidelines, updated utilizing a thorough and systematic approach to literature analysis and national consensus process, are now easily accessible to the global community via the newly developed digital platform. For additional details on specific topics, readers are encouraged to review materials on the online portal: https://GMDI.org/.

Modeling correlates of low bone mineral density in patients with phenylalanine hydroxylase deficiency.

Phenylalanine hydroxylase (PAH) deficiency is an inherited metabolic disorder requiring life-long restriction of dietary protein and phenylalanine-free medical food. Low bone mineral density (BMD) is reported, but factors associated with BMD Z-score (standard deviations from normal) are unknown. We examined associations between clinical and dietary parameters and total BMD Z-score in PAH deficiency patients, and developed models to predict Z-score. Data collected from patients >4 years of age (n = 88; mean age = 18.8 y; 61 % female) included demographic, clinical, laboratory, and dietary intakes. Adjusted Spearman's correlation coefficients were calculated between parameters and TBMD Z-score, measured by dual energy x-ray absorptiometry (DXA). Parameters approaching significance (p-value < 0.10) were candidate predictors for four linear regression models predicting TBMD Z-score. To validate, model-predicted Z-scores were compared to DXA Z-scores. Mean TBMD Z-score was -0.326; 18 (20.4 %) had Z-score < -1. Z-scores were positively correlated with dietary vitamin D, calcium, and medical food intake and compliance with prescription, and negatively with dietary carbohydrate, sugar, caffeine intake, glycemic load, and prescribed medical food (grams protein/day; p-value < 0.05). The best model included medical food compliance, medical food intake, caffeine intake, and bone-specific alkaline phosphatase (r-square = 0.364). This model predicted Z-score category [normal or low (<-1)] with sensitivity = 66.7 %, likelihood ratio = 14.7, and AUC = 0.83 compared to DXA Z-score. No subjects had low BMD for chronological age (Z-score ≤ -2). Compliance with medical food prescription was the strongest predictor of TBMD Z-score. One model, if validated in a separate sample of patients with more cases of low BMD, showed potential to estimate TBMD Z-score using routine clinical patient parameters.

Longitudinal quality of life analysis in a phenylketonuria cohort provided sapropterin dihydrochloride.

BACKGROUND: Sapropterin dihydrochloride effectively lowers plasma phenylalanine (Phe) for at least a third of phenylketonuria (PKU) patients, with potential for increased dietary Phe tolerance and decreased medical food requirement. OBJECTIVE: To investigate long-term quality of life (QOL) in patients with phenylketonuria (PKU) who took sapropterin (BH4, Kuvan®) for up to one year. METHODS: 37 PKU patients, ages 10-49 years, were asked to complete a PKU-specific self-report QOL questionnaire (QOLQ) at baseline, 1, 4, 8, and 12 months. Questions were scored on a 5-point Likert scale under 5 sub-sections measuring Impact, Worries, Satisfaction, Support, and General wellbeing in relation to PKU. Responders with a plasma Phe decrease ≥ 15% after 1 month on sapropterin remained on the drug; Nonresponders ceased sapropterin after the trial month. Responders able to relax medical diet and maintain plasma Phe control were classified as Definitive; Responders unable to relax medical diet were classified as Provisional. All patients were routinely monitored by a registered dietitian. Data was analyzed in SPSS 19.0 using regression techniques. RESULTS: Of 17 Responders, 11 could maintain adequate Phe control on a less restrictive diet. One year mean Impact sub-score trends improved significantly for all sapropterin response groups, with greatest improvement among Definitive Responders (p < 0.0001). Satisfaction sub-scores also improved for Definitive Responders (p = 0.001). Trends for Total QOL score improved significantly over time for both Definitive (p = 0.001) and Provisional Responders (p = 0.028). Improvements in Definitive Responder scores were associated with increased Phe tolerance (Impact: p < 0.0001, Satisfaction: p = 0.022, Total QOL: p = 0.005) and MF adjustment (Satisfaction: p = 0.014, Total QOL: p = 0.026). Other sub-section scores remained steady, unaffected by sapropterin response or diet modification. CONCLUSION: Increased Phe tolerance and reduced MF requirement in sapropterin Definitive Responders improves QOL perception across one year, specifically for life impact and satisfaction.

The effects of sapropterin on urinary monoamine metabolites in phenylketonuria.

BACKGROUND: Sapropterin dihydrochloride (BH4, tetrahydrobiopterin) can lower plasma phenylalanine (Phe) concentrations for a subset of patients with phenylketonuria (PKU), an inborn error of metabolism. Studies suggest that monoamine neurotransmitter concentrations are low in PKU patients. Sapropterin functions as a cofactor for hydroxylases specific to Phe, tyrosine, and tryptophan metabolism, pathways essential for catecholamine and serotonin synthesis. OBJECTIVE: The objective of this study is to determine the impact of sapropterin on monoamine neurotransmitter status in patients with PKU. DESIGN: 58 PKU subjects were provided 20 mg/kg of sapropterin for 1 month. Those who responded with at least a 15% decrease in plasma Phe received sapropterin for 1 year, while Non-responders discontinued it. After an additional 3 months, Responders who demonstrated increased Phe tolerance and decreased medical food dependence were classified as Definitive, whereas Responders unable to liberalize their diet without compromising plasma Phe control were identified as Provisional. At study visits, patients provided blood for plasma amino acids, 3-day diet records, and 12-hour urine samples analyzed for epinephrine (E), dopamine (DA), dihydroxyphenylacetate (DOPAC), homovanillic acid (HVA), 3-methoxytyramine (3MT), serotonin (5HT), and 5-hydroxyindole acetic acid (5HIAA) using HPLC with electrochemical detection. RESULTS: Compared with healthy non-PKU controls, subjects with PKU had significantly lower baseline concentrations of DA, HVA, 3MT, 5HT, and 5HIAA (p < 0.001 for all). Medical food protein intake had a direct association with DA, HVA, 5HT, and 5HIAA during the study (p < 0.05 for all), while plasma Phe had an inverse association with these markers (p < 0.01 for all). DOPAC was also associated with plasma Phe throughout the year (p = 0.035), although not at baseline. Patients with PKU had a significant increase in HVA (p = 0.015) after 1 month of sapropterin. When stratifying by Responder and Non-Responder status, significance of HVA increase in Non-responders (p = 0.041) was confirmed, but not in Responders (p = 0.081). A declining trend in urinary 5HIAA, significant only after controlling for plasma Phe (p = 0.019), occurred for Definitive Responders during the 1-year study. CONCLUSION: Urinary monoamine concentrations are low in patients with PKU and are influenced by oral sapropterin and medical food intake, highlighting the importance of these therapies to neurotransmitter metabolism in phenylketonuria.

Accuracy of six anthropometric skinfold formulas versus air displacement plethysmography for estimating percent body fat in female adolescents with phenylketonuria.

BACKGROUND: The reliability of studies investigating biological and therapeutic factors that influence body composition in PKU patients depends on accurate anthropometric measurements. OBJECTIVE: To determine the precision of six anthropometric skinfold equations versus air displacement plethysmography (ADP) for predicting body fat (BF) percentage in female adolescents with PKU. DESIGN: Skinfold and ADP measurements were recorded from a cross section of 59 female patients with PKU, ages 10-19 years. Anthropometric measures were used to calculate percent BF using equations published by Peterson et al., Loftin et al. (TAAG), Slaughter et al., Wilmore and Behnke, Durnin and Womersley, and Jackson et al. Bland-Altman agreement analysis and Lin's concordance correlation coefficient (ρ c) were used to determine the precision of each equation compared with percent BF determined by ADP. RESULTS: Adolescent females with PKU had a mean BF content of 33% measured by ADP, with an inverse association to birth cohort (r = -0.3, P = 0.016). Based on the Bland-Altman method for evaluating agreement, only Peterson's equation did not differ significantly from ADP percent BF results (P = 0.23). Peterson's skinfold equation yielded percent BF estimates with the smallest mean difference from ADP and the smallest standard deviation (0.76 ± 4.8), whereas Slaughter's equation had the largest (-7.7 ± 7.4). Loftin's TAAG equation had the least mean percent error (2.2%), while Slaughter's equation had the highest (19%). Both TAAG and Peterson's equations had the highest concordance correlation coefficients (ρ c = 0.8, ρ c = 0.8), while Slaughter's equation had the lowest (ρ c = 0.3). CONCLUSIONS: Peterson's equation is a precise surrogate for ADP when estimating percent BF in female adolescents with PKU, though Loftin's TAAG equation is also effective. Observed decreases in adiposity correlating with birth cohort could reflect steady improvements in patient nutrition care.

BH(4) therapy impacts the nutrition status and intake in children with phenylketonuria: 2-year follow-up.

The impact of tetrahydrobiopterin (BH(4)) treatment on phenylalanine tolerance, medical-food consumption, and nutrition status in patients with phenylketonuria (PKU) was investigated. Six children (5-12 years) with well-controlled PKU, responding to a BH(4) dose of 20 mg/kg per day, were assessed for 24 months. Mean dietary phenylalanine tolerance increased from 421 ± 128 to 1470 ± 455 mg/day. Height Z scores significantly improved from 0.25 ± 0.99 at baseline to 0.53 ± 1.16 at 24 months (p for trend < 0.001). Patients tolerated more phenylalanine and more intact protein and required less medical food (protein supplement). Improved linear growth and nutrition status was seen over the course of the 24-month follow-up. Due to the variation in phenylalanine tolerance, dietary recommendations should be tailored to the patient's individual requirements.

Citrus polymethoxylated flavones improve lipid and glucose homeostasis and modulate adipocytokines in fructose-induced insulin resistant hamsters.

The present study was undertaken to determine whether supplementation with polymethoxylated flavones (PMFs) could ameliorate the fructose-induced hypertriglyceridemia and other metabolic abnormalities associated with insulin resistance (IR) in hamsters. Following feeding with the fructose diet, hamsters were supplemented orally with PMF-L or PMF-H (62.5 and 125 mg/kg/day) for 4 weeks. Both PMF-treated groups showed a statistically significant (p<0.05) decrease in serum triglyceride (TG) and cholesterol levels compared to the fructose-fed control group. The fructose control group at the end of the study showed elevated serum insulin and impaired insulin sensitivity (glucose intolerance). On the other hand, PMF-supplemented groups showed a reversal in these metabolic defects, including a decrease in insulin level and an improvement in glucose tolerance. PMF supplementation also reduced TG contents in the liver and heart and was able to regulate adipocytokines by significantly suppressing TNF-alpha, INF-gamma, IL-1beta and IL-6 expression and increasing adiponectin in IR hamsters. The mechanism of PMF on the activation of peroxisome proliferator-activated receptors (PPAR) was also explored. PMF-H supplementation significantly increased PPARalpha and PPARgamma protein expression in the liver. This is the first report of positive effects of PMF on adipocytokine production and on PPAR expression in IR hamsters. This study suggests that PMF can ameliorate hypertriglyceridemia and its anti-diabetic effects may occur as a consequence of adipocytokine regulation and PPARalpha and PPARgamma activation.

Green tea leaf extract improves lipid and glucose homeostasis in a fructose-fed insulin-resistant hamster model.

The present study evaluated the effect of green tea (Camellia sinensis L.) leaf extract on triglyceride and glucose homeostasis in a fructose-fed hypertriglyceridemic, insulin-resistant hamster model. There was a significant decrease in plasma triglyceride levels following supplementation of the green tea epigallocatechin gallate-enriched extract (42% at 150 mg/(kg day) to 62% at 300 mg/(kg day) for 4 weeks). Compared to baseline, the fructose control group at the end of the study showed elevated serum insulin and apolipoprotein B levels, and decreased serum adiponectin levels. The fructose/green tea extract group showed a reversal in all of these metabolic defects, including an improvement in glucose levels during a glucose tolerance test. Triglyceride content was also examined in various tissues and compared to the control fructose group; supplementation of the green tea extract (300 mg/kg) reduced triglyceride content in liver and heart tissues. There was molecular evidence of improved lipid and glucose homeostasis based on peroxisome proliferator-activated receptor (PPAR) protein expression. Compared to the control fructose group, supplementation of the green tea extract (300 mg/kg) significantly increased PPARalpha and PPARgamma protein expression. In summary, the data suggest that intake of the green tea extract ameliorated the fructose-induced hypertriglyceridemia and the insulin-resistant state in part through PPAR.