Cysteine supplementation improves the erythrocyte glutathione synthesis rate in children with severe edematous malnutrition

Alzheimer's Disease: A Review of Pathology, Current Treatments, and the Potential Therapeutic Effect of Decreasing Oxidative Stress by Combined Vitamin D and l-Cysteine Supplementation

Significance: Excess oxidative stress and neuroinflammation are risk factors in the onset and progression of Alzheimer's disease (AD) and its association with amyloid-β plaque accumulation. Oxidative stress impairs acetylcholine (ACH) and N-methyl-d-aspartate receptor signaling in brain areas that function in memory and learning. Glutathione (GSH) antioxidant depletion positively correlates with the cognitive decline in AD subjects. Treatments that upregulate GSH and ACH levels, which simultaneously decrease oxidative stress and inflammation, may be beneficial for AD. Recent Advances: Some clinical trials have shown a benefit of monotherapy with vitamin D (VD), whose deficiency is linked to AD or with l-cysteine (LC), a precursor of GSH biosynthesis, in reducing mild cognitive impairment. Animal studies have shown a simultaneous decrease in ACH esterase (AChE) and increase in GSH; combined supplementation with VD and LC results in a greater decrease in oxidative stress and inflammation, and increase in GSH levels compared with monotherapy with VD or LC. Therefore, cosupplementation with VD and LC has the potential of increasing GSH, downregulation of oxidative stress, and decreased inflammation and AChE levels. Future Directions: Clinical trials are needed to determine whether safe low-cost dietary supplements, using combined VD+LC, have the potential to alleviate elevated AChE, oxidative stress, and inflammation levels, thereby halting the onset of AD. Goal of Review: The goal of this review is to highlight the pathological hallmarks and current Food and Drug Administration-approved treatments for AD, and discuss the potential therapeutic effect that cosupplementation with VD+LC could manifest by increasing GSH levels in patients. Antioxid. Redox Signal. 40, 663-678.

Protein intake affects erythrocyte glutathione synthesis in young healthy adults in a repeated-measures trial

BACKGROUND

In 2005, the Institute of Medicine advised using methods other than nitrogen balance (NB) for determining protein requirements. Since then, protein requirements using indicator amino acid oxidation (IAAO) have been published and are higher than NB. Glutathione (GSH), a tripeptide of cysteine, glutamate, and glycine, is a principal antioxidant that can be used as a functional indicator of protein adequacy.

OBJECTIVES

The aim of this study was to measure changes in erythrocyte GSH kinetics [fractional synthesis rate (FSR) and absolute synthesis rate (ASR)] in healthy adults following a range of protein intakes at and above the current recommendations.

METHODS

Sixteen healthy adults [8 males and 8 females, aged 25.6 ± 0.9 y (mean ± SEM)] were studied at 4 of 6 protein intakes ranging from 0.6 to 1.5 g⋅kg-1⋅d-1. Erythrocyte GSH kinetics were assessed during a 7-h infusion of [U-13C2-15N]glycine following 2 d of adaptation to each protein intake. Blood and urine tests were performed to measure oxidative stress markers, plasma homocysteine, triglycerides, plasma amino acid concentrations, 5-L-oxoproline (5-OP), and urinary sulfate. The protein intake that maximized GSH synthesis was determined using mixed-effect change-point regression in R. Primary and secondary outcomes were analyzed using linear mixed-effects and repeated-measures analysis of variance with Tukey's post hoc test.

RESULTS

The protein intake that maximized GSH FSR at 78%⋅d-1 was 1.0 g⋅kg-1⋅d-1 (95% confidence interval: 0.63, 1.39). GSH ASR was significantly lower at 0.6 and 0.8 g⋅kg-1⋅d-1 than at 1.5 g⋅kg-1⋅d-1 (2.03 and 2.17, respectively, compared with 3.71 mmol⋅L-1⋅d-1). Increasing the protein intake led to increased urinary sulfate but did not affect erythrocyte GSH concentration, plasma oxidative stress markers, triglycerides, homocysteine, or 5-OP.

CONCLUSIONS

A protein intake of 1.0 g⋅kg-1⋅d-1 maximized GSH synthesis, which is in agreement with earlier IAAO-derived protein requirements of 0.93 to 1.2 g⋅kg-1⋅d-1. These findings suggest that recommendations based on NB (0.66 g⋅kg-1⋅d-1) may underestimate protein needs for adequate health. This trial was registered at clinicaltrials.gov as NCT02971046.

A cost-effective, "mix & act" G-quadruplex/Cu (II) metal-nanozyme-based ratiometric fluorescent platform for highly sensitive and selective cysteine/bleomycin detection and multilevel contrary logic computing

Versatile nanozymes with fascinating catalytic properties provide inspiring and effective options for biosensing and pharmaceutical analysis. Herein, we report the first nanozyme-based ratiometric fluorescent platform for cysteine (Cys) and bleomycin (BLM) detection by harnessing the cost-effective and "mix & act" G-quadruplex/Cu(II) (G4/Cu) metal-nanozyme with satisfactory peroxidase-like activity, which was fully proven by circular dichroism (CD), electron paramagnetic resonance (EPR) spectra and reactive oxygen species (ROS) scavenging experiments. Based on the catalytic oxidation of G4/Cu metal-nanozyme toward two fluorescent substrates (Amplex Ultrared, AU; Scopoletin, Sc) with opposite responses in the presence of H2O2, and the specific interaction between Cu2+ and targets, we achieved the highly sensitive detection of Cys and BLM. Through recording the fluorescence changes of AU (emission at 590 nm, F590) and Sc (emission at 465 nm, F465), we obtained good linear relationships between ratiometric fluorescence values (F590/F465) and variable contents of targets, resulting in the competitive LODs of Cys (6.7 nM) and BLM (10 nM), respectively. Moreover, this platform presented high selectivity (without the need for masking agent) and acceptable performance in human serum samples. Furthermore, a library of DNA contrary logic pairs (CLPs) and multilevel concatenated circuits were fabricated based on the reverse dual-output of the above platform, enriching the building blocks of biocomputing. This work not only enlightened the design of affordable, "mix & act" type nanozyme-based ratiometric biosensors with high reliability, but also facilitated the pluralistic application of nucleic acid-templated nanozymes to innovative biocomputing.

A new lysosome-targeted Cys probe and its application in biology and food samples

Cysteine (Cys) is a sulfur-containing amino acid that plays an important role in living systems. The most common way to supplement the body with exogenous Cys is through the consumption of Cys-rich foods. Therefore, it is important to detect and analyze Cys in living systems and food samples. However, most of the Cys fluorescent probes developed so far are limited to the detection of the cellular environment only, and very few probes can take into account the detection of Cys in plant roots and food samples. In this paper, a novel fluorescent probe LN-NCS targeting the detection of Cys in lysosomes was designed and synthesized by modifying the naphthalimide fluorophore. The probe LN-NCS has a large Stokes shift (140 nm), low cytotoxicity, low detection limit (16.3 nM), and high selectivity, and probe LN-NCS reacts with Cys to produce the compound LN-NH2 with good fluorescence quantum yield (Ф = 0.81). Probe LN-NCS can be used to detect Cys in cells, zebrafish, plant roots, food samples, and environmental water samples. In addition, by modeling cellular inflammation, we have demonstrated that probe LN-NCS can detect changes in Cys concentration induced by cellular inflammation, providing a potential tool to better study the cellular inflammatory environment.

A Novel Fluorescence Probe Based on Azamonardine for Detecting and Imaging Cysteine in Cells and Zebrafish with High Selectivity and Sensitivity

A novel fluorescent probe based on azamonardine (Aza) fluorophore was designed and synthesized for the highly selective detection of cysteine (Cys) in vivo and in vitro. After reacting with acryloyl chloride, the fluorescence of Aza is effectively quenched, resulting in the formation of the Aza-acryl probe. Upon the addition of Cys, the ester bond of Aza-acryl is cleaved, releasing a new compound (Compound 1) with strong fluorescence, thereby achieving fluorescence turn-on detection of Cys. The structure of Aza-acryl was characterized using X-ray crystallography and NMR spectroscopy. Additionally, density functional theory was employed to elucidate the quenching mechanism of the acyl group on the Aza. Aza-acryl exhibits high selectivity towards Cys and distinguishes it from other biothiols such as homocysteine (Hcy) and glutathione (GSH). The mechanism of Aza-acryl for detecting Cys was investigated through HPLC, NMR spectroscopy, high-resolution mass spectrometry, and reaction kinetics experiments. Aza-acryl demonstrates excellent imaging capabilities for Cys in cells and zebrafish, providing a reliable and selectable tool for the detection and imaging of Cys in biological systems.

Rational design of a novel acryl-modified CQDs fluorescent probe for highly selective detection and imaging of cysteine in vitro and in vivo

A novel fluorescent nanoprobe CQDs-O-Acryl has been designed and synthesized to directly and accurately identify Cys over other biothiols in PBS (10 mM, pH 7.4) buffer. The carbon quantum dots (CQDs-OH) (λ_ex/em maxima = 495/525 nm) were fabricated by a solvothermal method using resorcinol as the carbon source. The CQDs-O-Acryl was achieved through covalently grafting the acryloyl group on the surface of carbon quantum dots by nuclear reaction based on static quenching. The structure and morphology of CQDs-OH and CQDs-O-Acryl have been characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis absorption spectroscopy. Upon the addition of Cys, the ester bond of CQDs-O-Acryl has been broken, and the free CQDs were released by conjugated addition and cyclization reactions successively, emitting strong green fluorescence at 525 nm (λ_ex = 495 nm). Under the optimized conditions, CQDs-O-Acryl exhibited good sensing of Cys within the range 0.095-16 μM (the LOD of 0.095 μM). Due to the high sensitivity, reliability, fast fluorescence response (10 min), and low toxicity of CQDs-O-Acryl, it was successfully applied to fluorescence imaging of Cys in A549 cells and zebrafish.

A "turn-on" inverse opal photonic crystal fluorescent sensing film for detection of cysteine and its bioimaging of living cells

A "turn-on" inverse opal photonic crystal fluorescent sensing film infiltrated with a coumarin derivative is reported for the reliable and accurate detection of cysteine in human serum and fluorescence imaging of living cells. The coumarin derivative containing allyl ester specifically reacts with cysteine by ammonolysis to generate a fluorescent product whose emission wavelength is at ~ 535 nm, providing a selective fluorescence detection for cysteine. The emitted fluorescence is significantly enhanced due to the slow photon effect derived from the photonic crystal film. This is because the emission wavelength is overlapped with the blue-band edge of the photonic stopband of the selected inverse opal film. The fluorescence enhancement effect endows the prepared inverse opal film with highly sensitive detection with a limit of detection of 3.23 × 10^-9 mol/L and a wide linear detection range of 1 × 10^-7 - 1 × 10^-3 mol/L. A fast response within 30 s toward cysteine is also achieved due to the three-dimensional interconnected macroporous structure with a high-specific surface area of the inverse opal film. The prepared inverse opal fluorescent sensing film has been successfully applied to the detection of cysteine in human serum and bioimaging of living cells. In the diluted human serum, the recoveries for the detection of cysteine were 97.92 - 107.20%, and the relative standard deviations were 2.61-9.04%, demonstrating the potential applicability of the inverse opal fluorescent sensing film to real sample analysis. The method may provide a universal strategy for constructing various photonic crystal fluorescent sensing films by using different fluorescent probes.

A simple lysosome-targeted fluorescent probe based on flavonoid for detection of cysteine in living cells

Cysteine (Cys) is one of the most important biothiols that plays a crucial role in many physiological and pathological processes, and therefore it is of great importance to detect and analyze Cys in subcellular environments, such as in lysosomes. However, only a few fluorescent probes were reported to be capable of detecting Cys in lysosomes selectively. In this wok, we designed and developed a simple, accessible flavone-based fluorescent probe LFA for detecting Cys in lysosomes. Morpholine was employed as the targeting unit for lysosome, and acrylate group was chosen as the Cys-response unit. The probe was easily prepared by a two-step procedure and displayed large Stokes shift, high sensitivity, turn-on response toward Cys over homocysteine (Hcy), glutathione (GSH), and other amino acids. With low cytotoxicity and good cell permeability, the probe could be successfully applied for fluorescence imaging of Cys in living cells. Furthermore, colocalization experiment revealed that lysosomal-targetable ability of LFA was significant. These results indicated that such simple fluorescent probe could provide a promising tool for detection of lysosomal Cys in living biological systems.

Refeeding Syndrome Developed in a Patient With Kwashiorkor Can Mimic Findings of Mitochondrial Disorder

Kwashiorkor is a serious nutritional disease. The 7-month-old male patient presented with severe metabolic acidosis and elevated liver enzymes. His condition was similar to fatty acid oxidation defect. He was taken to the hospital on the previous day with complaints of poor sucking and difficulty breathing. Treatment of upper respiratory tract infection was provided and then he returned to his home. He was cyanotic in bed after 12 hours. The patient, who was taken to the hospital unconscious and not fed for 12 hours, was not given any food orally in the first health center. Until laboratory tests are done, only iv electrolyte and a fluid containing dextrose were given. When the laboratory results were found to be significantly pathological, he was urgently referred to our hospital 4 hours after the admission. The content of the iv treatment applied at the time of referral was not clearly written. Low electrolytes, uric acid, liver enzymes, urea and creatinine elevation were detected at an outer center. Ketosis, lactic acidosis and dibasic aciduria were detected in urine organic acid analysis. He was diagnosed with Kwashiorkor and refeeding syndrome according to the clinical and laboratory findings. His complaints improved with appropriate treatment.

One-carbon metabolism in children with marasmus and kwashiorkor

BACKGROUND

Kwashiorkor is a childhood syndrome of edematous malnutrition. Its precise nutritional precipitants remain uncertain despite nine decades of study. Remarkably, kwashiorkor's disturbances resemble the effects of experimental diets that are deficient in one-carbon nutrients. This similarity suggests that kwashiorkor may represent a nutritionally mediated syndrome of acute one-carbon metabolism dysfunction. Here we report findings from a cross-sectional exploration of serum one-carbon metabolites in Malawian children.

METHODS

Blood was collected from children aged 12-60 months before nutritional rehabilitation: kwashiorkor (N = 94), marasmic-kwashiorkor (N = 43) marasmus (N = 118), moderate acute malnutrition (N = 56) and controls (N = 46). Serum concentrations of 16 one-carbon metabolites were quantified using LC/MS techniques, and then compared across participant groups.

FINDINGS

Twelve of 16 measured one-carbon metabolites differed significantly between participant groups. Measured outputs of one-carbon metabolism, asymmetric dimethylarginine (ADMA) and cysteine, were lower in marasmic-kwashiorkor (median µmol/L (± SD): 0·549 (± 0·217) P = 0·00045 & 90 (± 40) P < 0·0001, respectively) and kwashiorkor (0·557 (± 0·195) P < 0·0001 & 115 (± 50) P < 0·0001), relative to marasmus (0·698 (± 0·212) & 153 (± 42)). ADMA and cysteine were well correlated with methionine in both kwashiorkor and marasmic-kwashiorkor.

INTERPRETATION

Kwashiorkor and marasmic-kwashiorkor were distinguished by evidence of one-carbon metabolism dysfunction. Correlative observations suggest that methionine deficiency drives this dysfunction, which is implicated in the syndrome's pathogenesis. The hypothesis that kwashiorkor can be prevented by fortifying low quality diets with methionine, along with nutrients that support efficient methionine use, such as choline, requires further investigation.

FUNDING

The Hickey Family Foundation, the American College of Gastroenterology, the NICHD, and the USDA/ARS.

Beneficial Effects of Plant Extracts and Bioactive Food Components in Childhood Supplementation

The pivotal role of childhood nutrition has always roused a growing interest from the scientific community. Plant extracts and bioactive dietary components play a significant role in the maintenance of human health and wellness, with the potential to modulate risk factors and manage symptoms for a large number of common childhood disorders such as memory impairment, respiratory illnesses, gastrointestinal disorders, metabolic derangements, and pathologies related to the oral cavity. This review is designed to highlight the health benefits of botanical extracts and bioactive dietary components in children as evidenced by clinical trials, considering their safety with regards to childhood sensibilities. The supplementation of children with the herbal extracts or bioactive components mentioned in this review leads to the conclusion that they are useful for treating various ailments, with no serious adverse events being reported. However, for the limited number of investigations specifically focused on the safety of such products in children, time is needed to expand the literature data covering the safety of childhood supplementation with botanical extract and bioactive food components.

Dietary intake of sulfur amino acids and risk of kwashiorkor malnutrition in eastern Democratic Republic of the Congo

BACKGROUND

Kwashiorkor is an often-fatal type of severe acute malnutrition affecting hundreds of thousands of children annually, but whose etiology is still unknown. Evidence suggests inadequate sulfur amino acid (SAA) status may explain many signs of the condition but studies evaluating dietary protein intake in relation to the genesis of kwashiorkor have been conflicting. We know of no studies of kwashiorkor that have measured dietary SAAs.

OBJECTIVES

We aimed to determine whether children in a population previously determined to have high prevalence of kwashiorkor [high-prevalence population (HPP)] have lower dietary intakes of SAAs than children in a low-prevalence population (LPP).

METHODS

A cross-sectional census survey design of 358 children compared 2 previously identified adjacent populations of children 36-59 mo old in North Kivu Province of the Democratic Republic of the Congo. Data collected included urinary thiocyanate (SCN), cyanogens in cassava-based food products, recent history of illness, and a 24-h quantitative diet recall for the child.

RESULTS

The HPP and LPP had kwashiorkor prevalence of 4.5% and 1.7%, respectively. A total of 170 children from 141 households in the LPP and 169 children from 138 households in the HPP completed the study. A higher proportion of HPP children had measurable urinary SCN (44.8% compared with 29.4%, P < 0.01). LPP children were less likely to have been ill recently (26.8% compared with 13.6%, P < 0.01). Median [IQR] intake of SAAs was 32.4 [22.9-49.3] mg/kg for the LPP and 29.6 [18.1-44.3] mg/kg for the HPP (P < 0.05). Methionine was the first limiting amino acid in both populations, with the highest risk of inadequate intake found among HPP children (35.1% compared with 23.6%, P < 0.05).

CONCLUSIONS

Children in a population with a higher prevalence of kwashiorkor have lower dietary intake of SAAs than children in a population with a lower prevalence. Trial interventions to reduce incidence of kwashiorkor should consider increasing SAA intake, paying particular attention to methionine.

A fluorescent probe with dual acrylate sites for discrimination of different concentration ranges of cysteine in living cells

Monitoring of cysteine (Cys) is of significant importance for studying Cys-involved biological functions and clinically diagnosing Cys-related diseases. Recently, few fluorescent probes with two different reacting sites were reported to be capable of sensing different concentration ranges of Cys with distinct fluorescence signals, particularly suiting for bioimaging. However, due to relative sophisticated synthesis and moderate selectivity, the applications of these probes were still severely restricted. In this work, we proposed a novel probe design strategy by utilizing two same reacting groups, instead of two different reacting groups, to simplify the synthesis route and minimize the interference from competing species. Same reacting groups in a probe with different steric hindrances could exhibit different reactivities to Cys. This probe showed distinguishable fluorescence peak wavelengths towards low and high concentration ranges of Cys, giving green and blue emissions, respectively. Moreover, this probe was successfully applied for monitoring of Cys concentration in living cells. We believe this work provided a simpler strategy for dual-site fluorescent probes to sense difference concentration ranges of Cys, which may inspire more probe design in future.

Metabolomic changes in severe acute malnutrition suggest hepatic oxidative stress: a secondary analysis

Severe acute malnutrition (SAM), due to poor energy and/or protein intake, is associated with poor growth, depressed immune function, and long-term impacts on metabolic function. As the liver is a major metabolic organ and malnutrition poses metabolic stress, we hypothesize that SAM will be associated with alterations in the hepatic metabolome reflective of oxidative stress, gluconeogenesis, and ketogenesis. Thus, the purpose of this secondary analysis was to understand how SAM alters hepatic metabolism using a piglet model. Weanling piglets were feed either a reference (REF) or protein-energy deficient diet (MAL) for 5 weeks. After dietary treatment MAL piglets were severely underweight (weight-for-age Z-score of -3.29, Welch's t test, P = .0007), moderately wasted (weight-for-length Z-score of-2.49, Welch's t test, P = .003), and tended toward higher hepatic triglyceride content (Welch's t test, P = .07). Hematologic and blood biochemical measurements were assessed at baseline and after dietary treatment. The hepatic metabolome was investigated using ¹H-NMR spectroscopy. Hepatic concentrations of betaine, cysteine, and glutathione tended to be lower in MAL (Welch's t test with FDR correction, P < .1), while inosine, lactate, and methionine sulfoxide concentrations were higher in MAL (inosine: P = .0448, lactate: P = .0258, methionine sulfoxide: P = .0337). These changes suggest that SAM is associated with elevated hepatic oxidative stress, increased gluconeogenesis, and alterations in 1-carbon metabolism.

Amino acid-enriched plant-based RUTF treatment was not inferior to peanut-milk RUTF treatment in restoring plasma amino acid levels among patients with oedematous or non-oedematous malnutrition

Ready-to-use therapeutic food (RUTF) with adequate quality protein is used to treat children with oedematous and non-oedematous severe acute malnutrition (SAM). The plasma amino acid (AA) profile reflects the protein nutritional status; hence, its assessment during SAM treatment is useful in evaluating AA delivery from RUTFs. The objective was to evaluate the plasma AAs during the treatment of oedematous and non-oedematous SAM in community-based management of acute malnutrition (CMAM) using amino acid-enriched plant-based RUTFs with 10% milk (MSMS-RUTF) or without milk (FSMS-RUTF) compared to peanut milk RUTF (PM-RUTF). Plasma AA was measured in a non-blinded, 3-arm, parallel-group, simple randomized controlled trial conducted in Malawi. The RUTFs used for SAM were FSMS-RUTF, MSMS-RUTF or PM-RUTF. A non-inferiority hypothesis was tested to compare plasma AA levels from patients treated with FSMS-RUTF or MSMS-RUTF with those from patients treated with PM-RUTF at discharge. For both types of SAM, FSMS-RUTF and MSMS-RUTF treatments were non-inferior to the PM-RUTF treatment in restoration of the EAA and cystine except that for FSMS-RUTF, methionine and tryptophan partially satisfied the non-inferiority criteria in the oedematous group. Amino-acid-enriched milk-free plant-source-protein RUTF has the potential to restore all the EAA, but it is possible that enrichment with amino acids may require more methionine and tryptophan for oedematous children.

Neurobehavioral and immune-toxic impairments induced by organic methyl mercury dietary exposure in Nile tilapia Oreochromis niloticus

Although substantial knowledge of mercury toxicity in fish has been assembled; until now, studies investigating the toxic impacts in Nile tilapia (Oreochromis niloticus) following dietary exposure to organic methyl mercury (MeHg) are less prolific. Accordingly, the current study aimed to evaluate the impacts of MeHg on neurobehavioral and immune integrity in Nile tilapia after dietary exposure. Two hundred and twenty-five juvenile Nile tilapia (19.99 ± 0.33 g) were allocated into five groups in triplicates (15 fish/replicate). G1, G2, G3, G4, and G5. O. niloticus were fed corresponding basal diets containing 0, 0.5, 1, 1.5, and 2 mg/kg diet MeHg chloride (MeHgCl) daily for 30 days, zero value represented the control G1 group. The results showed that MeHg induced significant alterations in O. niloticus behavior, the swimming behavior was significantly decreased, while scratching, biting, and fin tugging behaviors were significantly augmented. Moreover; chasing, mouth pushing, and butting behaviors were significantly increased in all the exposed groups. MeHg significantly decreased brain acetylcholine esterase (AChE) and serum immunoglobulin M (IgM) levels in all the exposed groups. Meanwhile, serum levels of lysozyme (LYZ), nitric oxide (NO), superoxide dismutase (SOD) malondialdehyde (MDA), protein carbonyl (PCO), and 8 hydroxy 2 deoxyguanosine (8OH2dG) were significantly elevated in all the exposed groups except for serum reduced glutathione (GSH) content was significantly decreased implying oxidative stress (OS), lipid peroxidation (LPO), protein, DNA damage and impaired immune response of the exposed tilapia. MeHg significantly altered transcriptional expression of immune-related genes including (TNF-α, IL-1β, and IL-8, and IL-10) in all the exposed groups. From the obtained outcomes, the present research is the premier to investigate that dietary MeHg exposure in O. niloticus significantly induced neurobehavioral and immune defense impairments in a dose-related manner. This study exhibits that dietary MeHg may pose a potential threat to the O. niloticus populations.

Amino Acids in Endoplasmic Reticulum Stress and Redox Signaling

Proteins are the chains of amino acids linked via peptide bonds. In cells, newly synthesized proteins are modified and folded in the endoplasmic reticulum (ER) and matured to be functional proteins before they are transported to other tissues or organs. In addition to protein synthesis, the ER is also a stress-sensing organelle for diverse biological functions, such as calcium storage, lipid synthesis, and cellular metabolism. Nutrient deprivation, accumulation of reactive oxygen species, and other intracellular insults can activate ER stress and unfolded protein response (UPR) to restore homeostasis. Dysfunction of the ER influences cellular physiology and metabolism, and contributes to the pathogenesis of various diseases. Amino acids are the building blocks for proteins of eukaryotic organisms. Both in vivo and in vitro studies have found that amino acids can function as signaling molecules to regulate gene expression, cell proliferation and apoptosis, immune response, and antioxidant capacity in numerous biological processes. Importantly, several lines of studies have indicated that amino acids regulate the abundances of proteins implicated in UPR and the redox state, therefore restoring the intracellular homeostasis. Amino acids play an important role in regulating ER stress and redox homeostasis in animal cells for their survival, growth, and development.

Glucose-6-Phosphate Dehydrogenase Deficiency Activates Endothelial Cell and Leukocyte Adhesion Mediated via the TGFβ/NADPH Oxidases/ROS Signaling Pathway

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common genetic inherited trait among humans, affects ~7% of the global population, and is associated with excess risk of cardiovascular disease (CVD). Transforming growth factor-β (TGF-β) regulates immune function, proliferation, epithelial-mesenchymal transition, fibrosis, cancer, and vascular dysfunction. This study examined whether G6PD deficiencies can alter TGF-β-mediated NADPH oxidases (NOX) and cell adhesion molecules (CAM) in human aortic endothelial cells (HAEC). Results show that treatment with high glucose and the saturated free fatty acid palmitate significantly downregulated G6PD; in contrast, mRNA levels of TGF-β components, NOX and its activity, and reactive oxygen species (ROS) were significantly upregulated in HAEC. The expression levels of TGF-β and its receptors, NOX and its activity, and ROS were significantly higher in HG-exposed G6PD-deficient cells (G6PD siRNA) compared to G6PD-normal cells. The protein levels of adhesion molecules (ICAM-1 and VCAM-1) and inflammatory cytokines (MCP-1 and TNF) were significantly increased in HG-exposed G6PD-deficient cells compared to G6PD-normal cells. The adherence of monocytes (SC cells) to HAEC was significantly elevated in HG-treated G6PD-deficient cells compared to control cells. Pharmacological inhibition of G6PD enhances ROS, NOX and its activity, and endothelial monocyte adhesion; these effects were impeded by NOX inhibitors. The inhibition of TGF-β prevents NOX2 and NOX4 mRNA expression and activity, ROS, and adhesion of monocytes to HAEC. L-Cysteine ethyl ester (cell-permeable) suppresses the mRNA levels of TGF-β and its receptors, along with NOX2 and NOX4, and decreases NOX activity, ROS, and adhesion of monocytes to HAEC. This suggests that G6PD deficiency promotes TGF-β/NADPH oxidases/ROS signaling, the expression of ICAM-1 and VCAM-1, and the adhesion of leukocytes to the endothelial monolayer, which can contribute to a higher risk for CVD.

Substitution of Dietary Sulfur Amino Acids by dl-2-Hydroxy-4-Methylthiobutyric Acid Reduces Fractional Glutathione Synthesis in Weaned Piglets

BACKGROUND

Cys is limiting for reduced glutathione (GSH) synthesis and can be synthesized from Met. We hypothesized that the dietary Met hydroxyl analogue dl-2-hydroxy-4-methylthiobutyric acid (dl-HMTBA) affects Cys and GSH metabolism and oxidative stress defense differently than Met.

OBJECTIVE

The objective was to elucidate whether dl-HMTBA supplementation of a Met-deficient diet affects Cys flux, GSH fractional synthetic rate (FSR), and the basal oxidative stress level relative to Met supplementation in pigs.

METHODS

Twenty-nine male German Landrace piglets aged 28 d were allocated to 3 dietary groups: a basal diet limiting in Met (69% of Met plus Cys requirement) supplemented with either 0.15% l-Met (LMET; n = 9), 0.15% dl-Met (DLMET; n = 11), or 0.17% dl-HMTBA (DLHMTBA; n = 9) on an equimolar basis. At age 54 d the pigs received a continuous infusion of [1-13C]-Cys to calculate Cys flux and Cys oxidation. After 3 d, GSH FSR was determined by [2,2-2H2]-glycine infusion, and RBC GSH and oxidized GSH concentrations were measured. At age 62 d the animals were killed to determine hepatic mRNA abundances of enzymes involved in GSH metabolism, GSH concentrations, and plasma oxidative stress defense markers.

RESULTS

The Cys oxidation was 21-39% and Cys flux 5-15% higher in the fed relative to the feed-deprived state (P < 0.001). On average, GSH FSR was 49% lower (P < 0.01), and RBC GSH and total GSH concentrations were 12% and 9% lower, respectively, in DLHMTBA and DLMET relative to LMET pigs (P < 0.05). In the feed-deprived state, Gly flux, the GSH:oxidized glutathione (GSSG) ratio, RBC GSSG concentrations, plasma oxidative stress markers, and the hepatic GSH content did not differ between groups.

CONCLUSIONS

Although GSH FSR was higher in LMET compared with DLMET or DLHMTBA feed-deprived pigs, these differences were not reflected by lower oxidative stress markers and antioxidant defense enzymes in LMET pigs.

L-glutamine for sickle cell disease: Knight or pawn?

Oxidative stress is an important contributor to the pathophysiology of sickle cell disease. The pathways involved are complex and interlinked. L-glutamine is an amino acid with myriad roles in the body, including the synthesis of antioxidants, such as reduced glutathione and the cofactors NAD(H) and NADP(H), as well as nitric oxide—so it has therapeutic potential as an antioxidant. However, the relative impact of L-glutamine on the redox environment in red blood cells in sickle cell disease is not fully understood, and there are few therapeutic trials in sickle cell disease. Following the FDA approval of L-glutamine for sickle cell disease, more research is still needed to understand its clinical effects and role in therapy.

Optimized one-pot derivatization and enantioseparation of cysteine: Application to the study of a dietary supplement

Cysteine is a sulfur-containing amino acid which plays an outstanding role in many biological pathways in mammals. The analysis and quantification of native cysteine remains a critical issue due to its highly reactive thiol group evolving to the disulfide cystine derivative through oxidation reaction. Aimed at improving the derivative stability, cysteine was labelled with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), which reacts with both amino and thiol groups. The derivatization was optimized and the chemical identity of the reaction product was assessed via high-resolution mass spectrometry. The NBD-cysteine derivative resulted stable for 10 days. This derivative was enantioresolved (α and R_S equal to 1.25 and 2.70, respectively) thanks to a (R,R)-Whelk-O1 phase with the following chromatographic setting: eluent, MeOH/water-90/10 (v/v) with 15 mM ammonium formate (pwsH 6.0); column temperature, 35 °C; flow rate, 1.0 mL/min. The developed method was validated following the ICH guidelines and applied for the quality control of a L-cysteine containing dietary supplement.

Protein and amino acids for skeletal muscle health in aging

Proteins and its building blocks, amino acids, have many physiological roles in the body. While some amino acids can be synthesized endogenously, exogenous protein and amino acids are necessary to maintain homeostasis. Because skeletal muscle contains a large portion of endogenous protein and plays important roles in movement, regulation, and metabolism, imbalanced protein and amino acid availability may result in clinical conditions including skeletal muscle atrophy, impaired muscle growth or regrowth, and functional decline. Aging is associated with changes in protein metabolism and multiple physiological and functional alterations in the skeletal muscle that are accentuated by decreased dietary protein intake and impaired anabolic responses to stimuli. Inactivity and chronically elevated inflammation of the skeletal muscle can initiate and/or augment pathological remodeling of the tissue (i.e., increase of fat and fibrotic tissues and atrophy of the muscle). Defining an adequate amount of dietary protein that is appropriate to maintain the availability of amino acids for biological needs is necessary but is still widely debated for older adults. This chapter will provide (i) an overview of dietary protein and amino acids and their role in skeletal muscle health; (ii) an overview of skeletal muscle structure and function and the deterioration of muscle that occurs with advancing age; (iii) a discussion of the relationship between protein/amino acid metabolism and skeletal muscle decline with aging; and (iv) a brief discussion of optimal protein intakes for older adults to maintain skeletal muscle health in aging.

Thiol-Redox Regulation in Lung Development and Vascular Remodeling

Significance: Redox homeostasis is finely tuned and governed by distinct intracellular mechanisms. The dysregulation of this either by external or internal events is a fundamental pathophysiologic base for many pulmonary diseases. Recent Advances: Based on recent discoveries, it is increasingly clear that cellular redox state and oxidation of signaling molecules are critical modulators of lung disease and represent a final common pathway that leads to poor respiratory outcomes. Critical Issues: Based on the wide variety of stimuli that alter specific redox signaling pathways, improved understanding of the disease and patient-specific alterations are needed for the development of therapeutic targets. Further Directions: For the full comprehension of redox signaling in pulmonary disease, it is essential to recognize the role of reactive oxygen intermediates in modulating biological responses. This review summarizes current knowledge of redox signaling in pulmonary development and pulmonary vascular disease.

Nutrition rehabilitation of children with severe acute malnutrition: Revisiting studies undertaken by the National Institute of Nutrition

Severe acute malnutrition (SAM) in children under five years is an important public health problem due to associated high mortality and long-term health consequences. Research on the dietary causes of SAM, especially the role and relative importance of dietary protein, in the aetiology of oedematous malnutrition, has led to considerable debates and controversies. The present article revisits some of the debates in this field, where the researchers at the National Institute of Nutrition (NIN), Hyderabad, India, with their pioneering work, have contributed to the global literature on the various facets of the disease. Highlighting the importance of energy as a bigger problem than protein malnutrition is a noteworthy contribution of NIN's research. It is, however, important to examine the protein quality of the diets in light of the new information on the lysine requirements. The article argues that the currently dominating hypothesis of free radical theory requires a critical review of the supporting evidence. Over the past few decades, the research has focused on low-cost diets using locally available foods. The article also argues that solutions based on local foods, being acceptable and sustainable, need to be strengthened for their effective delivery through the existing nutrition programmes. Recent evidence shows that the use of ready-to-use therapeutic foods (RUTF) with high micronutrient density may be linked with higher mortality possibly due to the high iron content, which could be counterproductive. There are several unaddressed concerns regarding the potential long-term impact of consumption of RUTF in children with SAM. More evidence and a cautious approach are, therefore, needed before implementing these solutions.

Hyperglycemia (high-glucose) decreases L-cysteine and glutathione levels in cultured monocytes and blood of Zucker diabetic rats

L-Cysteine (LC) is an essential precursor of GSH biosynthesis. GSH is a major physiological antioxidant, and its depletion increases oxidative stress. Diabetes is associated with lower blood levels of LC and GSH. The mechanisms leading to a decrease in LC in diabetes are not entirely known. This study reports a significant decrease in LC in human monocytes exposed to high glucose (HG) concentrations as well as in the blood of type 2 diabetic rats. Thus, a significant decrease in the level of LC in response to exposure to HG supports the assertion that uncontrolled hyperglycemia contributes to a reduction of blood levels of LC and GSH seen in diabetic patients. Increased requirement of LC to replace GSH needed to scavenge excess ROS generated by hyperglycemia can result in lower levels of LC and GSH. Animal and human studies report that LC supplementation improves GSH biosynthesis and is beneficial in lowering oxidative stress and insulin resistance. This suggests that hyperglycemia has a direct role in the impairment of LC and GSH homeostasis in diabetes.

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism.

Glucose-6-phosphate dehydrogenase deficiency increases cell adhesion molecules and activates human monocyte-endothelial cell adhesion: Protective role of l-cysteine

Glucose-6-phosphate dehydrogenase is a major enzyme that supplies the reducing agent nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), which is required to recycle oxidized/glutathione disulfide (GSSH) to reduced glutathione (GSH). G6PD-deficient cells are susceptible to oxidative stress and a deficiency of GSH. Endothelial dysfunction is characterized by the loss of nitric oxide (NO) bioavailability, which regulates leukocyte adhesion to endothelium. G6PD-deficient endothelial cells (EC) demonstrate reduced expression of endothelial nitric oxide synthase (eNOS) and NO levels along with reduced GSH. Whether G6PD deficiency plays any role in EC dysfunction is unknown. The chronic inflammation commonly seen in those with metabolic syndrome, characterized by elevated levels of tumor necrosis factor (TNF) and monocyte chemoattractant protein 1 (MCP-1), provided an incentive for investigation of these cytokines as well. A GSH/G6PD-deficient model was created using human umbilical vein endothelial cells (HUVEC) treated with either buthionine sulfoximine (BSO), a pharmacological inhibitor of the rate-limiting enzyme of GSH biosynthesis (γ-glutamylcysteine synthetase), or with 6-aminonicotinamide (6-AN), an inhibitor of G6PD or G6PD siRNA. Normal and G6PD-deficient cells were also treated with pro-atherosclerotic stimuli such as high glucose, TNF, and MCP-1. After inhibiting or knocking down G6PD/GSH, the capacity of endothelial cells for monocyte recruitment was assessed by determining the expression of the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), which was upregulated by G6PD deficiency and accompanied by the presence of the oxidative stress markers NADPH oxidase 4 (NOX4), inducible nitric oxide synthase (iNOS), and reactive oxygen species (ROS). Treatment with the inhibitors BSO and 6-AN caused increased levels of adhesion molecule mRNA and monocyte-EC adhesion. Following treatment with high glucose, G6PD-deficient cells showed an increase in levels of ICAM-1 and VCAM-1 mRNA, as well as monocyte-EC adherence, compared with results seen in control cells. Treatment with l-cysteine (a precursor of GSH) protected endothelial cells by increasing GSH and attenuating ROS, ICAM-1, VCAM-1, and monocyte-EC adhesion. These results suggest that G6PD/GSH deficiency plays a role in endothelial dysfunction and that supplementation with l-cysteine can restore GSH levels and reduce the EC activation markers in G6PD-deficient conditions.

Gut microbial features can predict host phenotype response to protein deficiency

Malnutrition remains a major health problem in low- and middle-income countries. During low protein intake, <0.67 g/kg/day, there is a loss of nitrogen (N2 ) balance, due to the unavailability of amino acid for metabolism and unbalanced protein catabolism results. However, there are individuals, who consume the same low protein intake, and preserve N2 balance for unknown reasons. A novel factor, the gut microbiota, may account for these N2 balance differences. To investigate this, we correlated gut microbial profiles with the growth of four murine strains (C57Bl6/J, CD-1, FVB, and NIH-Swiss) on protein deficient (PD) diet. Results show that a PD diet exerts a strain-dependent impact on growth and N2 balance as determined through analysis of urinary urea, ammonia and creatinine excretion. Bacterial alpha diversity was significantly (P < 0.05, FDR) lower across all strains on a PD diet compared to normal chow (NC). Multi-group analyses of the composition of microbiomes (ANCOM) revealed significantly differential microbial signatures between the four strains independent of diet. However, mice on a PD diet demonstrated differential enrichment of bacterial genera including, Allobaculum (C57Bl6/J), Parabacteroides (CD-1), Turicibacter (FVB), and Mucispirillum (NIH-Swiss) relative to NC. For instance, selective comparison of the CD-1 (gained weight) and C57Bl6/J (did not gain weight) strains on PD diet also demonstrated significant pathway enrichment of dihydroorodate dehydrogenase, rRNA methyltransferases, and RNA splicing ligase in the CD-1 strains compared to C57Bl6/J strains; which might account in their ability to retain growth despite a protein deficient diet. Taken together, these results suggest a potential relationship between the specific gut microbiota, N2 balance and animal response to malnutrition.

Effects of the Usage of l-Cysteine (l-Cys) on Human Health

This review summarizes recent knowledge about the use of the amino acid l-Cysteine (l-Cys) through diet, nutritional supplements or drugs with the aim to improve human health or treat certain diseases. Three databases (PubMed, Scopus, and Web of Science) and different keywords have been used to create a database of documents published between 1950 and 2017 in scientific journals in English or Spanish. A total of 60,885 primary publications were ultimately selected to compile accurate information about the use of l-Cys in medicine and nutritional therapies and to identify the reported benefits of l-Cys on human health. The number of publications about the use of l-Cys for these purposes has increased significantly during the last two decades. This increase seems to be closely related to the rise of nutraceutical industries and personalized medicine. The main evidence reporting benefits of l-Cys usage is summarized. However, the lack of accurate information and studies based on clinical trials hampers consensus among authors. Thus, the debate about the role and effectiveness of supplements/drugs containing l-Cys is still open.

Comparative effects of acute-methionine loading on the plasma sulfur-amino acids in NAC-supplemented HIV+ patients and healthy controls

In this study, an acute overloading of methionine (MetLo) was used to investigate the trassulfuration pathway response comparing healthy controls and HIV+ patients under their usual diet and dietary N-acetyl-L-cysteine (NAC) supplementation. MetLo (0.1 g Met/kg mass weight) was given after overnight fasting to 20 non-HIV+ control subjects (Co) and 12 HIV+ HAART-treated patients. Blood samples were taken before and after the MetLo in two different 7-day dietary situations, with NAC (1 g/day) or with their usual diet (UD). The amino acids (Met, Hcy, Cys, Tau, Ser, Glu and Gln) and GSH were determined by HPLC and their inflow rate into circulation (plasma) was estimated by the area under the curve (AUC). Under UD, the HIV+ had lower plasma GSH and amino acids (excepting Hcy) and higher oxidative stress (GSSG/GSH ratio), similar remethylation (RM: Me/Hcy + Ser ratio), transmethylation (TM; Hcy/Met ratio) and glutaminogenesis (Glu/Gln ratio), lower transsulfuration (TS: Cys/Hcy + Ser ratio) and Cys/Met ratio and, higher synthetic rates of glutathione (GG: GSH/Cys ratio) and Tau (TG: Tau/Cys ratio). NAC supplementation changed the HIV pattern by increasing RM above control, normalizing plasma Met and TS and, increasing plasma GSH and GG above controls. However, plasma Cys was kept always below controls probably, associatively to its higher consumption in GG (more GSSG than GSH) and TG. The failure of restoring normal Cys by MetLo, in addition to NAC, in HIV+ patients seems to be related to increased flux of Cys into GSH and Tau pathways, probably strengthening the cell-antioxidant capacity against the HIV progression (registered at http://www.clinicaltrials.gov , NCT00910442).

Oxidation Resistance of the Sulfur Amino Acids: Methionine and Cysteine

Sulfur amino acids are a kind of amino acids which contain sulfhydryl, and they play a crucial role in protein structure, metabolism, immunity, and oxidation. Our review demonstrates the oxidation resistance effect of methionine and cysteine, two of the most representative sulfur amino acids, and their metabolites. Methionine and cysteine are extremely sensitive to almost all forms of reactive oxygen species, which makes them antioxidative. Moreover, methionine and cysteine are precursors of S-adenosylmethionine, hydrogen sulfide, taurine, and glutathione. These products are reported to alleviate oxidant stress induced by various oxidants and protect the tissue from the damage. However, the deficiency and excess of methionine and cysteine in diet affect the normal growth of animals; thereby a new study about defining adequate levels of methionine and cysteine intake is important.

Fluorescent coumarin-based probe for cysteine and homocysteine with live cell application

Cysteine (Cys) and homocysteine (Hcy) are two of important biological thiols and function as important roles in several biological processes. The development of Cys and Hcy probes will help to explore the functions of biothiols in biological systems. In this work, a new coumarin-based probe AC, containing an acryloyl moiety, was developed for Cys and Hcy detection in cells. Cys and Hcy undergo a nucleophilic addition and subsequent cyclization reaction to remove to the acryloyl group and yield a fluorescent product, 7-hydroxylcomuarin. The probe AC showed good selectivity for cysteine and homocysteine over glutathione and other amino acids and had low detection limits of 65nM for Cys and 79nM for Hcy, respectively. Additionally, confocal imaging experiments demonstrated that the probe AC can be applied to visualize Cys and Hcy in living cells.

Dietary thiols in exercise: oxidative stress defence, exercise performance, and adaptation

Endurance athletes are susceptible to cellular damage initiated by excessive levels of aerobic exercise-produced reactive oxygen species (ROS). Whilst ROS can contribute to the onset of fatigue, there is increasing evidence that they play a crucial role in exercise adaptations. The use of antioxidant supplements such as vitamin C and E in athletes is common; however, their ability to enhance performance and facilitate recovery is controversial, with many studies suggesting a blunting of training adaptations with supplementation. The up-regulation of endogenous antioxidant systems brought about by exercise training allows for greater tolerance to subsequent ROS, thus, athletes may benefit from increasing these systems through dietary thiol donors. Recent work has shown supplementation with a cysteine donor (N-acetylcysteine; NAC) improves antioxidant capacity by augmenting glutathione levels and reducing markers of oxidative stress, as well as ergogenic potential through association with delayed fatigue in numerous experimental models. However, the use of this, and other thiol donors may have adverse physiological effects. A recent discovery for the use of a thiol donor food source, keratin, to potentially enhance endogenous antioxidants may have important implications for endurance athletes hoping to enhance performance and recovery without blunting training adaptations.

Molecular Evidence for Differential Long-term Outcomes of Early Life Severe Acute Malnutrition

BACKGROUND

Severe acute malnutrition (SAM) in infants may present as one of two distinct syndromic forms: non-edematous (marasmus), with severe wasting and no nutritional edema; or edematous (kwashiorkor) with moderately severe wasting. These differences may be related to developmental changes prior to the exposure to SAM and phenotypic changes appear to persist into adulthood with differences between the two groups. We examined whether the different response to SAM and subsequent trajectories may be explained by developmentally-induced epigenetic differences.

METHODS

We extracted genomic DNA from muscle biopsies obtained from adult survivors of kwashiorkor (n=21) or marasmus (n=23) and compared epigenetic profiles (CpG methylation) between the two groups using the Infinium® 450K BeadChip array.

FINDINGS

We found significant differences in methylation of CpG sites from 63 genes in skeletal muscle DNA. Gene ontology studies showed significant differential methylation of genes in immune, body composition, metabolic, musculoskeletal growth, neuronal function and cardiovascular pathways, pathways compatible with the differences in the pathophysiology of adult survivors of SAM.

INTERPRETATION

These findings suggest persistent developmental influences on adult physiology in survivors of SAM. Since children who develop marasmus have lower birth weights and after rehabilitation have different intermediary metabolism, these studies provide further support for persistent developmentally-induced phenomena mediated by epigenetic processes affecting both the infant response to acute malnutrition and later life consequences.

FUNDING

Supported by a Grant from the Bill and Melinda Gates Foundation (Global Health OPP1066846), Grand Challenge "Discover New Ways to Achieve Healthy Growth."

EVIDENCE BEFORE THIS STUDY

Previous research has shown that infants who develop either kwashiorkor or marasmus in response to SAM differ in birth weight and subsequently have different metabolic patterns in both infancy and adulthood.

ADDED VALUE OF THIS STUDY

This study demonstrates epigenetic differences in the skeletal muscle of adult survivors of marasmus versus kwashiorkor and these differences are in genes that may underlie the longer-term consequences.

IMPLICATIONS OF ALL THE AVAILABLE EVIDENCE

These data are compatible with the different clinical responses to SAM arising from developmentally-induced epigenetic changes laid down largely before birth and provide evidence for the predictive adaptive response model operating in human development.

Effect of N-acetyl cysteine and glycine supplementation on growth performance, glutathione synthesis, anti-oxidative and immune ability of Nile tilapia, Oreochromis niloticus

An 8-week feeding trial was conducted to evaluate the effect of N-acetyl cysteine (NAC) and glycine supplementation on growth performance, glutathione (GSH) synthesis, anti-oxidative and immune ability of Nile tilapia, Oreochromis niloticus. Four practical diets were formulated, control, control +0.2% NAC, control +0.5% glycine, control +0.2% NAC +0.5% glycine. Each diet was randomly assigned to quadruplicate groups of 30 fish (approximately 9.5 g). The weight gain and specific growth rate were significantly increased with the supplementation of NAC and glycine. While they had no effect on feed efficiency feed intake and survival. Glutathion peroxidase (GPx) was increased by NAC and γ-glutamine cysteine synthase (γ-GCS) in plasma were increased by glycine. After the feeding trail, fish were challenged by Streptococcus iniae, fish fed the diet supplemented with NAC obtained significantly higher survival rate after 72 h challenge test. NAC also decreased malonaldehyde (MDA) in liver, increased glutathione S-transferase (GST) activity in plasma, up-regulated mRNA expression of Superoxide dismutase (SOD) and GPx in liver and headkidney. Dietary supplementation of glycine increased the anti-oxidative ability of tilapia through increase anti-oxidative enzyme activity (SOD, glutathione reductase, myeloperoxidase) and up-regulate anti-oxidative gene expression (SOD). Immune ability only enhanced by the supplementation of NAC through increased interleukin-1β (IL-1β) mRNA expression. These results clearly indicated that the supplementation of NAC and glycine can significantly improve the growth performance of tilapia, and NAC also enhance the anti-oxidative and immune capacity of tilapia, glycine could only enhance the anti-oxidative ability.

Developmental contributions to macronutrient selection: a randomized controlled trial in adult survivors of malnutrition

Background and objectives: Birthweight differences between kwashiorkor and marasmus suggest that intrauterine factors influence the development of these syndromes of malnutrition and may modulate risk of obesity through dietary intake. We tested the hypotheses that the target protein intake in adulthood is associated with birthweight, and that protein leveraging to maintain this target protein intake would influence energy intake (EI) and body weight in adult survivors of malnutrition.

Methodology: Sixty-three adult survivors of marasmus and kwashiorkor could freely compose a diet from foods containing 10, 15 and 25 percentage energy from protein (percentage of energy derived from protein (PEP); Phase 1) for 3 days. Participants were then randomized in Phase 2 (5 days) to diets with PEP fixed at 10%, 15% or 25%.

Results: Self-selected PEP was similar in both groups. In the groups combined, selected PEP was 14.7, which differed significantly (P < 0.0001) from the null expectation (16.7%) of no selection. Self-selected PEP was inversely related to birthweight, the effect disappearing after adjusting for sex and current body weight. In Phase 2, PEP correlated inversely with EI (P = 0.002) and weight change from Phase 1 to 2 (P = 0.002). Protein intake increased with increasing PEP, but to a lesser extent than energy increased with decreasing PEP.

Conclusions and implications: Macronutrient intakes were not independently related to birthweight or diagnosis. In a free-choice situation (Phase 1), subjects selected a dietary PEP significantly lower than random. Lower PEP diets induce increased energy and decreased protein intake, and are associated with weight gain.

Parkinson's disease managing reversible neurodegeneration

Traditionally, the Parkinson's disease (PD) symptom course has been classified as an irreversible progressive neurodegenerative disease. This paper documents 29 PD and treatment-induced systemic depletion etiologies which cause and/or exacerbate the seven novel primary relative nutritional deficiencies associated with PD. These reversible relative nutritional deficiencies (RNDs) may facilitate and accelerate irreversible progressive neurodegeneration, while other reversible RNDs may induce previously undocumented reversible pseudo-neurodegeneration that is hiding in plain sight since the symptoms are identical to the symptoms being experienced by the PD patient. Documented herein is a novel nutritional approach for reversible processes management which may slow or halt irreversible progressive neurodegenerative disease and correct reversible RNDs whose symptoms are identical to the patient's PD symptoms.

Antioxidant and Anti-Inflammatory Activities of Kenyan Leafy Green Vegetables, Wild Fruits, and Medicinal Plants with Potential Relevance for Kwashiorkor

Background. Inflammation, together with related oxidative stress, is linked with the etiology of kwashiorkor, a form of severe acute malnutrition in children. A diet rich in anti-inflammatory and antioxidant phytochemicals may offer potential for the prevention and treatment of kwashiorkor. We selected and assayed five leafy green vegetables, two wild fruits, and six medicinal plants from Kenya for their antioxidant and anti-inflammatory properties. Consensus regarding medicinal plant use was established from ethnobotanical data. Methods. Antioxidant activity and phenolic content were determined using the oxygen radical absorbance capacity (ORAC) assay and Folin-Ciocalteu procedure, respectively. Anti-inflammatory activity was assessed in vitro targeting the inflammatory mediator tumour necrosis factor-alpha (TNF-α). Results. Mangifera indica (leaves used medicinally) showed the greatest antioxidant activity (5940 ± 632 µM TE/µg) and total phenolic content (337 ± 3 mg GAE/g) but Amaranthus dubius (leafy vegetable) showed the greatest inhibition of TNF-α (IC₅₀ = 9 ± 1 μg/mL), followed by Ocimum americanum (medicinal plant) (IC₅₀ = 16 ± 1 μg/mL). Informant consensus was significantly correlated with anti-inflammatory effects among active medicinal plants (r² = 0.7639,  P = 0.0228). Conclusions. Several plant species commonly consumed by Kenyan children possess activity profiles relevant to the prevention and treatment of kwashiorkor and warrant further investigation.

Nutritional and other types of oedema, albumin, complex carbohydrates and the interstitium - a response to Malcolm Coulthard's hypothesis: Oedema in kwashiorkor is caused by hypo-albuminaemia

The various types of oedema in man are considered in relation to Starling's hypothesis of fluid movement from capillaries, with the main emphasis on nutritional oedema and the nephrotic syndrome in children. It is concluded that each condition has sufficient anomalous findings to render Starling's hypothesis untenable. The finding that the endothelial glycocalyx is key to control of fluid movement from and into the capillaries calls for complete revision of our understanding of oedema formation. The factors so far known to affect the function of the glycocalyx are reviewed. As these depend upon sulphated proteoglycans and other glycosaminoglycans, the argument is advanced that the same abnormalities will extend to the interstitial space and that kwashiorkor is fundamentally related to a defect in sulphur metabolism which can explain all the clinical features of the condition, including the formation of oedema.

Metabolic and nutritional support of critically ill patients: consensus and controversies

The results of recent large-scale clinical trials have led us to review our understanding of the metabolic response to stress and the most appropriate means of managing nutrition in critically ill patients. This review presents an update in this field, identifying and discussing a number of areas for which consensus has been reached and others where controversy remains and presenting areas for future research. We discuss optimal calorie and protein intake, the incidence and management of re-feeding syndrome, the role of gastric residual volume monitoring, the place of supplemental parenteral nutrition when enteral feeding is deemed insufficient, the role of indirect calorimetry, and potential indications for several pharmaconutrients.

Effect of High-Dose Cysteine Supplementation on Erythrocyte Glutathione: A Double-Blinded, Randomized Placebo-Controlled Pilot Study in Critically Ill Neonates

BACKGROUND

This study's objective was to determine if parenteral cysteine when compared with isonitrogenous noncysteine supplementation increases erythrocyte reduced glutathione (GSH) in neonates at high risk for inflammatory injury.

MATERIAL AND METHODS

Neonates with a score for neonatal acute physiology >10 requiring mechanical ventilation and parenteral nutrition (PN) were randomized in a double-blinded, placebo-controlled study to receive parenteral cysteine-HCl (CYS group) or additional PN amino acids (ISO group) at 121 mg/kg/d for ≥7 days. A 6-hour [(13)C2] glycine IV infusion was administered at study week 1 to determine the fractional synthetic rate of GSH (FSR-GSH).

RESULTS

Baseline characteristics were similar between the CYS (n = 17) and ISO groups (n = 21). Erythrocyte GSH and total glutathione concentrations, GSH:oxidized GSH (GSSG), and FSR-GSH after treatment were not different between groups. However, the CYS group had a larger individual positive change in GSH and total glutathione (infusion day - baseline) compared with the ISO group (P = .02 for each). After adjusting for treatment, a lower enrollment weight and rate of red blood cell transfusion were associated with a decreased change in total glutathione and GSH (P < .05 for each).

CONCLUSION

When compared with isonitrogenous noncysteine supplementation, high-dose cysteine supplementation for at least 1 week in critically ill neonates resulted in a larger and more positive individual change in GSH. Smaller infants and those who received transfused blood demonstrated less effective change in GSH with cysteine supplementation. The benefit of cysteine remains promising and deserves further investigation.

Efficacy of screening immune system function in at-risk newborns

This paper explores the introduction of a screening test to highlight impaired immune system status for newborn infants and its efficacy as a preventative clinical measure. Moreover, it is suggested that screening of the infantile immune system has the potential to highlight susceptibility to a range of infant and childhood diseases, bestowing an opportunity to introduce early intervention to reduce the incidence of these diseases. Development of the neonatal immune system is an important health issue, implicated in many childhood problems such as allergies, infection, and autoimmunity. The neonate has a limited immune system and ability to combat bacteria. Depleted levels of the tripeptide reduced glutathione (GSH) have been linked to numerous conditions and its intracellular level is acknowledged as an indicator of immune system function. Introduction of an immune system screening programme for infants is formally reviewed and assessed. Several benefits are reported in the treatment of impaired immune systems, a trial screening programme is proposed for at-risk infants to gather further evidence as to its efficacy. Infants at risk of impaired immune system function include cystic fibrosis, premature infants, and low birth weight infants. The interventions include breastfeeding, milk banks, and appropriate formula to support the immune system.

Effects of randomized supplementation of methionine or alanine on cysteine and glutathione production during the early phase of treatment of children with edematous malnutrition

BACKGROUND

We have shown that a low glutathione concentration and synthesis rate in erythrocytes are associated with a shortage of protein-derived cysteine in children with edematous severe acute malnutrition (SAM).

OBJECTIVE

We tested the hypothesis that methionine supplementation may increase protein-derived cysteine and upregulate cysteine synthesis, thereby improving glutathione synthesis during the early treatment of edematous SAM.

DESIGN

The cysteine flux, its de novo synthesis and release from protein breakdown, and erythrocyte glutathione synthesis rate were measured in 12 children with edematous SAM in the fed state by using stable isotope tracers at 3 clinical phases as follows: 3 ± 1 d (±SE) [clinical phase 1 (CP1)], 8 ± 1 d [clinical phase 2 (CP2)], and 14 ± 2 d (clinical phase 3) after admission. Subjects were randomly assigned to receive equimolar supplements (0.5 mmol ⋅ kg(-1) ⋅ d(-1)) of methionine or alanine (control) immediately after CP1.

RESULTS

In the methionine compared with the alanine group, cysteine flux derived from protein breakdown was faster at CP2 than CP1 (P < 0.05), and the change in plasma cysteine concentration from CP1 to CP2 was greater (P < 0.05). However, there was no evidence of a difference in cysteine de novo synthesis and its total flux or erythrocyte glutathione synthesis rate and concentration between groups.

CONCLUSIONS

Methionine supplementation increased cysteine flux from body protein but had no significant effect on glutathione synthesis rates. Although cysteine is made from methionine, increased dietary cysteine may be necessary to partially fulfill its demand in edematous SAM because glutathione synthesis rates and concentrations were less than previous values shown at full recovery. This study was registered at clinicaltrials.gov as NCT00473031.

Dietary supplementation with aromatic amino acids increases protein synthesis in children with severe acute malnutrition

Although 2 earlier studies reported that aromatic amino acid (AAA) supplementation of children with severe acute malnutrition (SAM) improved whole-body protein anabolism during the early postadmission (maintenance) phase of rehabilitation, it is not known whether this positive effect was maintained during the catch-up growth and recovery phases of treatment. This study aimed to determine whether supplementation with an AAA cocktail (330 mg · kg(-1) · d(-1)) vs. isonitrogenous Ala would improve measures of protein kinetics in 22 children, aged 4-31 mo, during the catch-up growth and recovery phases of treatment for SAM. Protein kinetics were assessed by measuring leucine, phenylalanine, and urea kinetics with the use of standard stable isotope tracer methods in the fed state. Supplementation started at the end of the maintenance period when the children were clinically/metabolically stable and continued up to full nutritional recovery. Three experiments were performed: at the end of maintenance (at ∼13 d postadmission), at mid-catch-up growth (at ∼23 d post- admission when the children had replenished 50% of their weight deficit), and at recovery (at ∼48 d postadmission when they had achieved at least 90% weight for length). Children in the AAA group had significantly faster protein synthesis compared with those in the Ala group at mid-catch-up growth (101 ± 10 vs. 72 ± 7 μmol phenylalanine · kg(-1) · h(-1); P < 0.05) and better protein balance at mid-catch-up growth (49 ± 5 vs. 30 ± 2 μmol phenylalanine · kg(-1) · h(-1); P < 0.05) and at recovery (37 ± 8 vs. 11 ± 3 μmol phenylalanine · kg(-1) · h(-1); P < 0.05). We conclude that dietary supplementation with AAA accelerates net protein synthesis in children during nutritional rehabilitation for SAM.

Cascade sensing of gold and thiols with imidazole-bearing functional porphyrins

An imidazole-bearing zinc porphyrin (PZn) has been designed for the selective detection of Au³⁺, and the porphyrin and gold complex (PZn·Au³⁺) can additionally be used to identify gold-binding functional groups such as cysteine residues and other mercaptans.

Effects of antioxidants on glutathione levels and clinical recovery from the malnutrition syndrome kwashiorkor – a pilot study

Kwashiorkor is a severe edematous form of malnutrition with high prevalence and lethality in many African countries, and repeatedly has been reported to be associated with oxidative stress. The therapy of kwashiorkor is still ineffective. In this pilot study, we tested the hypothesis that oral application of thiol-containing antioxidants increases glutathione status and is beneficial for the clinical recovery of kwashiorkor patients. The longitudinal clinical intervention study was carried out at St Joseph's Hospital, Jirapa, Ghana. Children with severe kwashiorkor were randomly assigned to either a standard treatment (ST) receiving a therapeutic protocol based on the recommendations of the WHO or to one of three study groups receiving in addition 2 x 600 mg reduced glutathione or 2 x 50 mg alpha-lipoic acid or 2 x 100 mg N-acetylcysteine per day. Patients were followed up clinically and biochemically for 20 days and compared with 37 healthy controls. Both glutathione and alpha-lipoic acid supplementation had positive effects on survival. Also, the blood glutathione concentrations correlated positively with survival rates. Furthermore, the initial skin lesions, glutathione and total protein concentrations were found to be strong predictors of survival. The data strongly suggest that a therapy restoring the antioxidative capacity by applying cysteine equivalents in the form of glutathione and/or alpha-lipoic acid is beneficial for biochemical and clinical recovery of kwashiorkor patients.