Early Development of Newborn Screening for HCU and Current Challenges

Classic homocystinuria (HCU) was added to newborn screening (NBS) by Robert Guthrie a few years after the disorder was first described. The justification for NBS was similar to that for PKU, that presymptomatic identification and early dietary treatment would prevent the clinical consequences, which, for HCU, are mental deficiency, ectopia lentis, skeletal abnormalities, and thromboembolism. It was assumed that identifying increased methionine in the screening blood specimen would identify all affected neonates. However, it is now clear that many with HCU are missed by NBS, mainly because the methionine level in the first days of life is normal or below the cutoff level in the NBS program. This includes virtually all of those with B6-responsive HCU. Thus, a more effective method of NBS for HCU should be considered. Included among the possibilities are decreasing the methionine cutoff level, requiring an increase in the Met/Phe ratio if the methionine level is not at or greater than the cutoff level, using methionine as the primary screen with homocysteine as a second-tier test, or replacing methionine with homocysteine as the primary screen. Homocysteine is the primary metabolite that increases in HCU, while the methionine increase is secondary, so homocysteine is usually increased before the increase in methionine, almost always during the first few days of life. Finally, targeted gene screening might be considered. All of these possibilities would impose added expense and labor to NBS, so meeting these challenges would likely require a regional or national effort.

Influence of bisoprolol and nebivolol on the spectrum of substituted amino acids in blood plasma of patients with stable angina

For many years, ß-blockers have been used to treat patients with coronary heart disease. In patients with stable angina, the effect of ß-blockers on the amino acid spectrum of blood serum has been studied. Its violation is considered as one of the pathogenetic links in the development of atherosclerosis. The study showed a more efficient action of nebivolol compared to bisoprolol on the amino acid imbalance. In patients with stable angina against the background of antianginal therapy, which included bisoprolol and nebivolol, there was a significant decrease in the total amount of amino acids, the amount of essential amino acids, and the amount of essential amino acids compared to the treatment. Against the background of the nebivolol treatment, there is a positive dynamics of sulfur-containing amino acids (methionine level was maintained, taurine level was significantly increased, cystine level was normalized), isoleucine level was normalized, which indirectly indicates cardioprotective and angiprotective effect of nebivolol.

FURTHER STUDIES ON URINARY 3-METHYLHISTIDINE EXCRETION AS AN INDIRECT INDEX OF DIETARY AMINO ACID ADEQUACY IN RATS

As a further step in the determination of the sen­sitivity of urinary 3-methylhistidine (3-MeH) to essential amino acid adequacy in diet, 36 male albino rats of the Wistar strain were divided into six groups +of six rats per group. Each group with an initial .mean live weight of 106.52 ± 0.54g was fed in in­dividual metabolic cages on a basal diet sup­plemented with graded levels of DL-methionine. Total methionine in diet ranged between 0.25 and 1.05%. The study lasted 10 days. The response of urinary 3-methylhistidine excretion to the graded levels of methionine in diet was compared to responses obtained from growth performance characteristics, plasma urea concentration, liver nitrogen and creatinine excretion. With the excep­tion of feed intake, all other indices of dietary pro­tein adequcy and efficient amino acid utilization viz growth rate, protein efficiency ratio, serum urea concentration, and creatinine excretion were significantly (P 0.05) to P 0.01) influenced by dietary methionine level. Maximum growth rate, liver N and urinary 3-methylhistidine were observed. in rats given 0.45% total methionine in diet. Supplementing the basal diet to contain 0.45% total,' methonine significantly (P 0.01) decreased serum urea concentration. Urinary 3-methylhistidlne excre­tion was found by regression analysis to be positively correlated to body weight gain (r = 0.73), feed intake (r = 0.61), urinary creatinine excretion (r = 0.74) and liver N (0.72) but negatively correlated to dietary methionine level (r = —0.41). We suggested that urinary 3-MeH excretion be added to the list of available indicts for dietary amino acid adequacy.

BIỂU HIỆN GEN SINH CƠ Ở GÀ RI LAI VÀ LƯƠNG PHƯỢNG KHI ĐƯỢC NUÔI BẰNG CÁC KHẨU PHẦN CÓ MỨC METHIONINE KHÁC NHAU

The aim of this study was to investigate the effects of methionine concentrations in diet on the expression of myogenic genes in Ri hybrid and Luong Phuong chickens at 12 weeks of age. A total of 240 Ri hybrid and 240 Luong Phuong one-day-old chickens of uniform body weight was divided into a 2 × 3 factorial arrangement of treatments with four replicate cages of 20 chicks per treatment. Six treatments were set up including 2 chicken types and three diets with low, adequate, high methionine concentrations compared to methionine level recommended by Evonik (2010) for colored chickens. At 12 weeks of age, 36 chickens from 2 groups were randomly chosen for the absolute and relative breast muscle weight calculation, and myogenic gene expression evaluation (myostatin, myf5, MEF2B) in breast muscle using RT-realtime PCR technique. The results showed that using the 0.08% higher of methionine level in diets than Evonik recommendation (2010) improved the absolute weight of breast muscle of the two colored chicken groups. The addition of methionine with 0.08% higher than Evonik recommendation (2010) decreased myostatin and increased MEF2B gene expression in Ri hybrid. On the other hand, using the 0.08% lower of methionine level in diets had no effect on gene expression of the three myogenic genes (myostatin, myf5 and MEF2B) comparing to using the adequate methionine diets. In the case of Luong Phuong chickens, the increasing methionine level in diets reduced myostatin gene expression, but increased myf5 and MEF2B gene expression.

EFFECT OF SALINITY CHANGES ON METHIONINE CONTENT IN TIGER GROUPER JUVENILE (Epinephelus fuscoguttatus)

This study was conducted to determine the effect of water salinity changes on methionine content in tiger grouper juvenile (Epinephelus fuscoguttatus). A total of 2,560 tiger grouper juveniles were used and divided into five groups consist of 1 control group (without exposed to salinity changes) and 4 treatment groups. The salinity was changed every 2, 3, 4, and 6 hours in treatment A, B, C, and D, respectively. Salinity levels were changed during 24 hours by lowering salinity level from 32 psu to 22 psu. Twenty five of fish were collected from each treatment for methionine content analysis. Data were analysed using one way analysis of variance (ANOVA). The results showed that there was a decrease in methionine content in all treatments. A significant decrease (P0.05) of methionine content in treatment A, B, and C were observed after 20 hours (1.15%), 18 hours (1.27%), and 16 hours (1.24%), respectively. While at 0 hours (control), the methionine content was 2.02%. Methionine level in treatment D was not significantly different (P0.05) compared to control group. As conclusion, rearing the tiger grouper juvenile with salinity fluctuations every 6 hours did not lead to methionine deficiency.

THE VALUE OF SULPHUR-CONTAINING AMINO-ACIDS IN BLOOD PLASMA AS PROGNOSTIC MARKERS OF COMPLICATED COURSE OF ST-SEGMENT ELEVATION MYOCARDIAL INFARCTION (STEMI) WITHOUT REPERFUSION THERAPY

Relevance. The sulfation of homocysteine is an important element in protecting cells against ischemic-reperfusion injury. In clinical studies the positive effect of N-acetylcysteine ​​on the reduction of necrosis was found in patients with STEMI. Objective of this study was to evaluate the baseline levels of sulphur-containing amino acids in plasma as predictors of early (on the day of admission) systolic dysfunction of left ventricle (SDLV) and acute heart failure (HF) in patients with STEMI without reperfusion therapy (RT). Material and methods. 92 patients with STEMI without RT were examined. The content of free plasma sulphur-containing aminо acids (homocysteine, cysteine ​​and methionine) was investigated on the day of admission by ion-exchanged liquid-column chromatography. Results. The complications of STEMI were associated with increased baseline levels of sulphur-containing aminо acids, especially, cysteine ​​and methionine. Its levels were significantly higher (at 71.7%, р<0.01, and 41.3%, р<0.05, respectively) in patients with early SDLV compared with patients with ejection fraction of left ventricle (LVEF) >40%. The multivariate logistic regression analysis revealed that the baseline level of cysteine in patients with STEMI remained an independent predictor of early (on the day of admission) SDLV (OR=17.4, p<0.001) after adjustment for anamnestic and laboratory factors. The sensitivity and specificity of baseline cysteine ​​level >0.49 mg/dl as a marker of early SDLV were 73.9% and 65.2% respectively (AUC=0.72, p=0.006). The multivariate analysis revealed that the baseline level of methionine was an independent predictor of acute HF on the day of admission after adjustment for laboratory factors (OR=25.9, p<0.001). Also methionine was an independent predictor of persistent / late HF on third day or later in total sampling (OR=25.9, p<0.001) after adjustment for demographic, anamnestic and clinic factors (OR=68.7, p<0.0001), as well as after adjustment for laboratory risk factors (OR=42.5, p<0.0001). The sensitivity and specificity of baseline methionine ​​level >0.31 mg/dl as a marker of persistent / late HF were 87.5% and 63.3% respectively (AUC = 0.77, p <0.0001). Also the baseline level of methionine was an independent predictor of persistent / late HF in patients with EFLV >40% after adjustment for demographic and anamnestic factors (OR=113.3, p <0,0001). The sensitivity and specificity of methionine ​​level >0.41 mg/dl as a marker of persistent / late HF in patients with EFLV >40% were 80.0% and 81.0% respectively (AUC=0.80, р<0.0001). Conclusions. The complicated course of STEMI without RT is associated with increased level of sulphur-containing aminо acids, especially, cysteine ​​and methionine. A higher level of cysteine ​​is associated with early SDLV independently from anamnesis risk factors and creatinine level in plasma. The risk of persistent / late HF (on third day and later) is associated with a higher level of methionine independently from demographic, anamnestic, clinical and laboratory factors risk.