Cysteine Supplementation Research Articles

Efficacy of N-Acetylcysteine (NAC) Against Malondialdehyde (MDA) Levels in Diabetic Cataracts: In vivo Study

Background: Diabetes mellitus is a systemic condition that affects various organs, including the eyes. N-acetylcysteine ​​(NAC) functions as an antioxidant because it belongs to a thiol group synthesis glutathione. However, the availability of cysteine ​​in the body is only 15%, so cysteine ​​supplementation can help with oxidative stress in diabetic cataracts. That it will prevent the reaction of lipid peroxidase and the formation of PUFA in the lens membrane, which causes damage to lens cells and is characterized by an increase in malondialdehyde. This study aims to determine the comparison of malondialdehyde levels in the lenses of diabetic cataract rats given or without topical NAC.
 Methods: 36 rats were divided into the control group (received streptozotocin) and treatment group (received streptozotocin and topical NAC. Intraperitoneal injection of streptozotocin was given 90 mg/kg BW and performed once a week for 3 weeks. GDP examination was performed the next day after the rats fasted for 16 hours from the vein. In the tail, GDP > 110 mg/dl categorized as diabetes. Topical NAC was given 4 times per day for 3 weeks. At the end of the study, the lens was extracted for the measurement of malondialdehyde.
 Results: The mean MDA levels in the control group were higher (2.90±0.71nmol/ml) than in the treatment group (2.33±0.38nmol/ml), p<0.05.
 Conclusion: NAC was effective in reducing oxidative stress levels in diabetic cataract lenses by lowering MDA levels better than the group that did not receive MDA in vivo.

Effect of heat exposure on the growth and developmental competence of bovine oocytes derived from early antral follicles

In dairy cows, low fertility caused by summer heat stress continues into the cooler autumn season. This can be caused by impaired oocyte quality in small growing follicles during summer. Here, we subjected oocyte–cumulus–granulosa complexes (OCGCs) derived from early antral follicles (0.5–1 mm) to in vitro growth (IVG) culture under two different temperature settings (the control and heat shock groups), and evaluated effects of heat exposure on growth and developmental competence of oocytes, factors affecting the developmental competence of oocytes (steroidogenesis of granulosa cells, oxidative stress in oocytes, and cell-to-cell communication between oocytes and somatic cells). Oocyte diameters after culture were smaller in the heat shock group. Although nuclear maturation and cleavage rates were similar between the groups, blastocyst rates were lower in the heat shock group (0.0%) than in the control group (27.7%), and reduced glutathione (GSH) levels in oocytes were lower in the heat shock group. Supplementation of cysteine, which stimulates GSH synthesis, increased GSH level and improved blastocyst rate of heat shocked oocytes (27.9%). These results suggest that heat exposure impairs the growth and developmental competence of oocytes in early antral follicles through GSH depletion, which can induce low fertility during summer and the following autumn.

Role of cysteine in the improvement of γ-aminobutyric acid production by nonproteolytic Levilactobacillus brevis in coculture with Streptococcus thermophilus

Previous research has showed that nonproteolytic Levilactobacillus brevis 145 (L) in coculture with Streptococcus thermophilus 1275 (S), not Lactobacillus delbrueckii ssp. bulgaricus (Lbu), was able to produce γ-aminobutyric acid (GABA) during milk fermentation in the presence of monosodium glutamate (MSG). It was assumed that differences of casein hydrolysis patterns between Strep. thermophilus 1275 and L. bulgaricus caused the phenomenon. Moreover, the GABA content was low and residual MSG was high in SL-fermented milk. In our research, comparison of peptide profiles determined by liquid chromatography/tandem mass spectrometry showed that αS2-casein, β-casein, and κ-casein degradation by L. bulgaricus and Strep. thermophilus varied. Importantly, the peptide number in the L and Lbu coculture group increased compared with the Lbu monoculture group, whereas the peptide number in the SL coculture group decreased in comparison with S monoculture group, suggesting that L. bulgaricus was not able to provide peptides for the growth of Lb. brevis 145. Furthermore, we found that after supplementation with cysteine (50 mg/L) during milk fermentation by SL, 10 g/L MSG was converted into 4.8 g/L GABA with a minimum level of residual MSG, viable cell counts of Lb. brevis and lactic acid production were increased, and the casein hydrolysis pattern was not influenced. Moreover, sulfhydryl group-containing chemicals including cystine, reduced glutathione, and oxidized glutathione showed effects similar to that of cysteine in improving GABA production. Finally, when L. bulgaricus YIB2 was combined with SL, supplementation of cysteine was also able to significantly improve GABA production.

Cysteine supplementation enhanced inhibitor tolerance of Zymomonas mobilis for economic lignocellulosic bioethanol production

Inhibitors in lignocellulosic hydrolysates are toxic to Zymomonas mobilis and reduce its bioethanol production. This study revealed cysteine supplementation enhanced furfural tolerance in Z. mobilis with a 2-fold biomass increase. Transcriptomic study illustrated that cysteine biosynthesis pathway was down-regulated while cysteine catabolism was up-regulated with cysteine supplementation. Mutants for genes involved in cysteine metabolism were constructed, and metabolites in cysteine metabolic pathway including methionine, glutathione, NaHS, glutamate, and pyruvate were supplemented into media. Cysteine supplementation boosted glutathione synthesis or H2S release effectively in Z. mobilis leading to the reduced accumulation of reactive oxygen species (ROS) induced by furfural, while pyruvate and glutamate produced in the H2S generation pathway promoted cell growth by serving as the carbon or nitrogen source. Finally, cysteine supplementation was confirmed to enhance Z. mobilis tolerance against ethanol, acetate, and corncob hydrolysate with an enhanced ethanol productivity from 0.38 to 0.55 g−1∙L−1∙h−1.

Protecting Effects of N-acetyl Cysteine Supplementation Against Lead and Cadmium-Induced Brain Toxicity in Rat Models

We aimed to investigate mitigating effects of N-acetylcysteine (NAC) on the oxidative stress, apoptosis and Parkinson's disease (PD)-related genes in the brain tissue of male rats exposed to continuous doses of cadmium and lead. Rats were randomly divided into five groups, including G1 (control), G2 (continuous dose of Cd), G3 (continuous dose of Pb), G4 (continuous dose of Cd + NAC), and G5 (continuous dose of Pb + NAC). Biomarkers of oxidative stress, malondialdehyde (MDA), and total antioxidant capacity (TAC) were measured. Expression of PD- and apoptosis-related genes was considered using RT-PCR. Chronic exposure to these heavy metals was associated with accumulation of Pb and Cd in the brain and blood and caused severe morphological changes in the brain, as well as decreased body and brain weights. Continuous exposure to Cd and Pb significantly decreased TAC content and SOD expression but increased MDA level in the brain tissues (P < 0.001). A significant increase was observed in expression of PD-related genes, Parkin, Pink1, LRRK2, SNCA, and Caspase-3 in the brain tissues following exposure to Cd and Pb. Pb exhibited stronger toxicity on the brain tissue compared to Cd. NAC supplementation not only improved morphological changes, but also compensated antioxidant capacity and expression of apoptosis- and PD-related genes in the brain tissues when compared to rats exposed to Pb and Cd alone. Chronic exposure to Pb and Cd is strongly associated with accumulation of these heavy metals in the brain, morphological changes, antioxidants depletion, oxidative stress, and brain cells apoptosis. Changes in expression of PD-related genes indicate the higher risk of PD among individuals who are chronically exposed to these heavy metals. NAC can protect brain tissue against Pb and Cd toxicity by elevating antioxidants capacity, mitigating oxidative stress, apoptosis, and down-regulating of PD-related genes.

Biosynthesis of Poly(3HB-co-3HP) with Variable Monomer Composition in Recombinant Cupriavidus necator H16.

Polyhydroxyalkanoates are attractive alternatives to traditional plastics. However, although polyhydroxybutyrate (PHB) is produced in large quantities by Cupriavidus necator H16, its properties are far from ideal for the manufacture of plastic products. These properties may be improved through its coproduction with 3-hydroxypropionate (3HP), which leads to the formation of the copolymer poly(3-hydroxybutyrate-co-3-hydroxypropionate) (poly(3HB-co-3HP). To achieve this, a pathway was designed to enable C.necator H16 to convert β-alanine to 3HP. The initial low levels of incorporation of 3HP into the copolymer were overcome by the overproduction of the native propionyl-CoA transferase together with PHA synthase from Chromobacterium sp. USM2. Following optimization of 3HP incorporation into the copolymer, the molar fraction of 3HP could be controlled by cultivation in medium containing different concentrations of β-alanine. Between 0 and 80 mol % 3HP could be achieved. Further supplementation with 2 mM cysteine increased the maximum 3HP molar fraction to 89%. Additionally, the effect of deletions of the phaA and phaB1 genes of the phaCAB operon on 3HP molar fraction were investigated. A phaAB1 double knockout resulted in a copolymer containing 91 mol % 3HP without the need for cysteine supplementation.

217 Comparative Effects of Dietary Methionine and Cysteine Supplementation on Redox Status and Intestinal Integrity in Immunologically Challenged-weaned Pigs

Abstract The aim was to investigate the effects of dietary Met and Cys supplementation in immunologically challenged-weaned pigs. Forty weaned piglets (6.51 ± 0.29 kg) were randomly allocated to five treatments and fed the assigned diets for 9 days. The treatments included: (1) sham-challenged control (SCC), (2) challenged control (CC), (3) MET (CC + 0.1% DL-Met supplementation), (4) CYS (CC + 0.1% L-Cys supplementation), and (5) MET+CYS (CC + 0.1% DL-Met and 0.1% L-Cys supplementation). Piglets were intramuscularly injected with either lipopolysaccharides (LPS; 30 μg/kg) or saline solution on day 7. All data were analyzed using single degree of freedom contrasts in the mixed procedure of SAS to test the effect of LPS challenge, Met supplementation, Cys supplementation, and Met × Cys supplementation. The CC group had lower (P &amp;lt; 0.05) villi height and villi surface area and glutathione (GSH) concentration and higher (P &amp;lt; 0.05) flux of 4-kDa fluorescein isothiocyanate dextran (FD4) in the jejunum than SCC group. Dietary Cys supplementation increased (P &amp;lt; 0.05) villi surface area, GSH concentration and reduced GSH: oxidized GSH and decreased (P &amp;lt; 0.05) the flux of FD4 in the jejunum. Dietary Met supplementation enhanced (P &amp;lt; 0.05) hepatic GSH content. Pigs in the MET group had greater mRNA abundance of IL-6 and IL-10 (P &amp;lt; 0.05) and lower serum IL-8 concentration than those in the CC group. There were Met × Cys interactions (P &amp;lt; 0.05) in serum IL-4 and IL-8 concentrations and hepatic Trolox equivalent antioxidant capacity. In conclusion, dietary L-Cys supplementation restored intestinal integrity and GSH concentration that were affected by LPS challenge. Dietary DL-Met supplementation improved hepatic GSH and reduced systemic inflammatory response, but antagonistic interaction with dietary Cys supplementation was observed in inflammatory response and redox status.

Cysteine improves boar sperm quality via glutathione biosynthesis during the liquid storage.

ObjectiveSperm is particularly susceptible to reactive oxygen species (ROS) stress. Glutathione (GSH) is an endogenous antioxidant that regulates sperm redox homeostasis. However, it is not clear whether boar sperm could utilize cysteine for synthesis GSH to protect sperm quality from ROS damage. Therefore, the present study was undertaken to elucidate the mechanism of how cysteine is involved in protecting boar sperm quality during liquid storage.MethodsSperm motility, membrane integrity, lipid peroxidation, 4-hydroxyIlonenal (4-HNE) modifications, mitochondrial membrane potential, as well as the levels of ROS, GSH, and, ATP were evaluated. Moreover, the enzymes (GCLC: glutamate cysteine ligase; GSS: glutathione synthetase) that are involved in glutathione synthesis from cysteine precursor were detected by western blotting.ResultsCompared to the control, addition of 1.25 mM cysteine to the liquid storage significantly increased boar sperm progressive motility, straight-line velocity, curvilinear velocity, beat-cross frequency, membrane integrity, mitochondrial membrane potential, ATP level, acrosome integrity, activities of superoxide dismutase and catalase, and GSH level, while reducing the ROS level, lipid peroxidation and 4-HNE modifications. It was also observed that the GCLC and GSS were expressed in boar sperm. Interestingly, when we used menadione to induce sperm with ROS stress, the menadione associated damages were observed to be reduced by the cysteine supplementation. Moreover, compared to the cysteine treatment, the γ-glutamylcysteine synthetase (γ-GCS) activity, GSH level, mitochondrial membrane potential, ATP level, membrane integrity and progressive motility in boar sperm were decreased by supplementing with an inhibitor of GSH synthesis, buthionine sulfoximine.ConclusionThese data suggest that boar sperm could biosynthesize the GSH from cysteine in vitro. Therefore, during storage, addition of cysteine improves boar sperm quality via enhancing the GSH synthesis to resist ROS stress.

Improvement of the Rhizoremediation efficiency of PAHs contaminated soil under cysteine treatment along with modeling

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of pollutants with mutagenic and carcinogenic properties. This study aimed to assess the effects of cysteine on the growth and resistance of the Festuca plant against PAHs-induced stress. The experiment was designed in six different groups and included control, contaminated soil with pyrene (Py) and phenanthrene (Phe) (200, 300, and 400 mg kg−1), and supplementation with cysteine (100, 200 mg L-1), all with or without the cultivation of Festuca grass. During the two 45- and 90-day periods, changes in the population of bacteria, the activity of soil enzymes: dehydrogenase (DHA) and peroxidase (POD), and the level of pyrene and phenanthrene removal were investigated. Furthermore, the Response Surface Methodology (RSM) model was also applied to determine the relationships between input and response parameters. Then, using the sensitivity analysis by Monte Carlo simulation, the effect of the examined parameters on the response parameters was determined. The results demonstrated that cysteine supplementation, along with Festuca cultivation, increased the number of bacteria, improved the activity of enzymes, and elevated the elimination of PAHs (p-value < 0.05).

Role of Pomegranate Peel Extract and N-Acetyl cysteine supplementation on Paracetamol-Induced Nephrotoxicity in Adult Male Albino Rats

Role of Pomegranate Peel Extract and N-Acetyl cysteine supplementation on Paracetamol-Induced Nephrotoxicity in Adult Male Albino Rats

Antioxidant supplementation ameliorates bull sperm parameters and fertilizing ability following the freeze-thaw process

This study's goal was to reveal the effects of antioxidant supplementation on motility, motion characters, morphology, DNA integrity, and fertilizing potential of cryopreserved bovine sperm. The ejaculates were collected from three Holstein bulls. At least ten ejaculates were collected per bull. The ejaculates were immediately separated into five aliquots, diluted in the Cryobos (Magapor Co. Ltd., Zaragoza, Spain) commercial extender, including 2.5 mM taurine, 2.5 mM cysteine, 2.5 mM methionine, 2.5 mM glutamine, and no additives were used. Afterward, they were frozen in 0.25 mL French straws, and liquid nitrogen was used for the storage of semen. The supplementation of methionine resulted in a higher subjective motility rate in comparison with the other groups. Taurine led to the lowest post-thawed CASA motility rate (p < 0.05). The addition of antioxidants did not cause any improvements in sperm motion characteristics when compared to the controls (p > 0.05). Cysteine led to a higher protection of acrosome abnormality, in comparison with the other groups (p < 0.05). For the comet test, the minimum percentage of sperm with damaged DNA was obtained in the groups with cysteine and glutamine (p < 0.05). There was not any significant difference among the groups in terms of pregnancy rates (p > 0.05). In conclusion, cysteine supplementation to the semen extender prior to freezing ameliorated the post-thawed semen quality.

EP019 - TRMU deficiency: a broad clinical spectrum responsive to cysteine supplementation

eP019 - TRMU deficiency: a broad clinical spectrum responsive to cysteine supplementation

Oxidative stress induces EGFR inhibition-related skin cell death

Cutaneous side effects are often observed in patients treated with chemotherapeutic agents, including those treated with epidermal growth factor receptor (EGFR) inhibitors. These side effects are not fatal but often require dose reduction of chemotherapies. The mechanisms of epidermal growth factor receptor inhibition-related dermatologic toxicities are unclear, and prophylactic approaches are not well-established. To explore the mechanisms of the cutaneous side effects induced by epidermal growth factor receptor inhibition, we analyzed the metabolome using human keratinocyte cells. We first demonstrated that afatinib and lapatinib induced apoptosis in HaCaT cells. Using liquid chromatography-mass spectrometry, we detected 676 and 482 metabolites and compounds in the cells and media, respectively. We observed diverse metabolic alterations, including glycolysis, TCA metabolism, and polyamine metabolism, and also found a change in glutathione metabolites after epidermal growth factor receptor inhibition, which led to the accumulation of reactive oxygen species. Supplementation of N-acetyl cysteine partly rescued the afatinib-induced apoptosis, suggesting that reactive oxygen species are involved in the cytotoxicity of skin cells. We observed epidermal growth factor receptor inhibitor-associated comprehensive metabolic changes in human keratinocyte cells, suggesting that oxidative stress evokes cutaneous side effects induced by EGFR inhibition.

Application of metabolic modeling for targeted optimization of high seeding density processes.

Process intensification by application of perfusion mode in pre‐stage bioreactors and subsequent inoculation of cell cultures at high seeding densities (HSD) has the potential to meet the increasing requirements of future manufacturing demands. However, process development is currently restrained by a limited understanding of the cell's requirements under these process conditions. The goal of this study was to use extended metabolite analysis and metabolic modeling for targeted optimization of HSD cultivations. The metabolite analysis of HSD N‐stage cultures revealed accumulation of inhibiting metabolites early in the process and flux balance analysis led to the assumption that reactive oxygen species (ROS) were contributing to the fast decrease in cell viability. Based on the metabolic analysis an optimized feeding strategy with lactate and cysteine supplementation was applied, resulting in an increase in antibody titer of up to 47%. Flux balance analysis was further used to elucidate the surprisingly strong synergistic effect of lactate and cysteine, indicating that increased lactate uptake led to reduced ROS formation under these conditions whilst additional cysteine actively reduced ROS via the glutathione pathway. The presented results finally demonstrate the benefit of modeling approaches for process intensification as well as the potential of HSD cultivations for biopharmaceutical manufacturing.

TRMU deficiency: A broad clinical spectrum responsive to cysteine supplementation

TRMU is a nuclear gene crucial for mitochondrial DNA translation by encoding tRNA 5-methylaminomethyl-2-thiouridylate methyltransferase, which thiolates mitochondrial tRNA. Biallelic pathogenic variants in TRMU are associated with transient infantile liver failure. Other less common presentations such as Leigh syndrome, myopathy, and cardiomyopathy have been reported. Recent studies suggested that provision of exogenous L-cysteine or N-acetylcysteine may ameliorate the effects of disease-causing variants and improve the natural history of the disease. Here, we report six infants with biallelic TRMU variants, including four previously unpublished patients, all treated with exogenous cysteine. We highlight the first report of an affected patient undergoing orthotopic liver transplantation, the long-term effects of cysteine supplementation, and the ability of the initial presentation to mimic multiple inborn errors of metabolism. We propose that TRMU deficiency should be suspected in all children presenting with persistent lactic acidosis and hypoglycemia, and that combined N-acetylcysteine and L-cysteine supplementation should be considered prior to molecular diagnosis, as this is a low-risk approach that may increase survival and mitigate the severity of the disease course.

A recurring NFS1 pathogenic variant causes a mitochondrial disorder with variable intra-familial patient outcomes

Iron‑sulfur clusters (FeSCs) are vital components of a variety of essential proteins, most prominently within mitochondrial respiratory chain complexes I-III; FeS assembly and distribution is performed via multi-step pathways. Variants affecting several proteins in these pathways have been described in genetic disorders, including severe mitochondrial disease. Here we describe a Christian Arab kindred with two infants that died due to mitochondrial disorder involving FeS containing respiratory chain complexes and a third sibling who survived the initial crisis. A homozygous missense variant in NFS1: c.215G>A; p.Arg72Gln was detected by whole exome sequencing. The NFS1 gene encodes a cysteine desulfurase, which, in complex with ISD11 and ACP, initiates the first step of FeS formation. Arginine at position 72 plays a role in NFS1-ISD11 complex formation; therefore, its substitution with glutamine is expected to affect complex stability and function. Interestingly, this is the only pathogenic variant ever reported in the NFS1 gene, previously described once in an Old Order Mennonite family presenting a similar phenotype with intra-familial variability in patient outcomes. Analysis of datasets from both populations did not show a common haplotype, suggesting this variant is a recurrent de novo variant.Our report of the second case of NFS1-related mitochondrial disease corroborates the pathogenicity of this recurring variant and implicates it as a hot-spot variant. While the genetic resolution allows for prenatal diagnosis for the family, it also raises critical clinical questions regarding follow-up and possible treatment options of severely affected and healthy homozygous individuals with mitochondrial co-factor therapy or cysteine supplementation.

Enteropeptidase inhibitor SCO-792 effectively prevents kidney function decline and fibrosis in a rat model of chronic kidney disease.

BackgroundInhibiting enteropeptidase, a gut serine protease regulating protein digestion, suppresses food intake and ameliorates obesity and diabetes in mice. However, the effects of enteropeptidase inhibition on kidney parameters are largely unknown. Here, we evaluated the chronic effects of an enteropeptidase inhibitor, SCO-792, on kidney function, albuminuria and kidney pathology in spontaneously hypercholesterolaemic (SHC) rats, a rat chronic kidney disease (CKD) model.MethodsSCO-792, an orally available enteropeptidase inhibitor, was administered [0.03% and 0.06% (w/w) in the diet] to 20-week-old SHC rats showing albuminuria and progressive decline in glomerular filtration rate (GFR) for five weeks. The effects of SCO-792 and the contribution of amino acids to these effects were evaluated.ResultsSCO-792 increased the faecal protein content, indicating that SCO-792 inhibited enteropeptidase in SHC rats. Chronic treatment with SCO-792 prevented GFR decline and suppressed albuminuria. Moreover, SCO-792 improved glomerulosclerosis and kidney fibrosis. Pair feeding with SCO-792 (0.06%) was less effective in preventing GFR decline, albuminuria and renal histological damage than SCO-792 treatment, indicating the enteropeptidase-inhibition-dependent therapeutic effects of SCO-792. SCO-792 did not affect the renal plasma flow, suggesting that its effect on GFR was mediated by an improvement in filtration fraction. Moreover, SCO-792 increased hydrogen sulphide production capacity, which has a role in tissue protection. Finally, methionine and cysteine supplementation to the diet abrogated SCO-792-induced therapeutic effects on albuminuria.ConclusionsSCO-792-mediated inhibition of enteropeptidase potently prevented GFR decline, albuminuria and kidney fibrosis; hence, it may have therapeutic potential against CKD.

Effect of glutamine and cysteine supplementation on quality of cryopreserved sperm of South American silver catfish

The aim of this study was to investigate the effects of different concentrations of glutamine (experiment 1) and glutamine + cysteine (experiment 2) on post-thaw sperm quality of South American silver catfish (Rhamdia quelen). The sperm was cryopreserved in cryoprotectant solution (fructose 50 g/L, powdered milk 50 g/L and methanol 100 ml/L) containing different glutamine concentrations (0, 2.5 and 5 mM; experiment 1) and a combination of glutamine (2.5 and 5 mM) and cysteine (2.5 and 5 mM; experiment 2). In experiment 1: glutamine supplementation groups increased DNA fragmentation; the concentration of carbonyl groups was lower and the concentration of sulfhydryl groups was higher in control; a higher activity of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and glutathione peroxidase (GPx) enzymes was observed in the 2.5 and 5 mM groups. In experiment 2: the group with 5 mM of cysteine +5 mM of glutamine presented the higher DNA damage; treatments with 5 mM of glutamine presented the higher concentration of carbonyl groups and a higher activity of CAT and GST. The findings of this study show that glutamine and cysteine, at the concentrations evaluated in this study, does not present satisfactory results but rather damaging effects on sperm quality of R. quelen.

The effect of cysteine and glutamine on human sperm functional parameters during vitrification.

Assuming the adverse effects of reactive oxygen species (ROS) on sperm function, this study was conducted to assess the effects of cysteine and glutamine as effective antioxidants on human sperm parameters under vitrification. Twenty normozoospermic samples were used. The samples were subjected to a vitrification process and cysteine (5 and 10mM) and glutamine (10 and 15mM). The sperm motility parameters, mitochondrial membrane potential (MMP), plasma membrane integrity (PMI), DNA damage and intracellular ROS damage were assessed for each sample. Statistical analyses showed that motility, mitochondrial membrane potential and DNA damage decreased in the vitrified groups with cysteine 5, 10mM and glutamine 10, 15mM separately. Also intracellular ROS increased significantly compared to the fresh group (p<.05). No significant differences were observed for PMI compared with the fresh group (p>.05). Supplementation of cysteine and glutamine in both concentrations separately decreased intracellular ROS and DNA damage of spermatozoa with significant increase in PMI, MMP and progressive motility compared to vitrified control group (p<.05). The results showed no significant effect of a specific concentration in cysteine and glutamine on sperm parameters compared to other concentrations. Both amino acids have the potential to improve the harmful effects of freezing on sperm parameters.

Docosahexaenoic acid inhibits the proliferation of Kras/TP53 double mutant pancreatic ductal adenocarcinoma cells through modulation of glutathione level and suppression of nucleotide synthesis.

The treatment of cancer cells obtained by blocking cellular metabolism has received a lot of attention recently. Previous studies have demonstrated that Kras mutation-mediated abnormal glucose metabolism would lead to an aberrant cell proliferation in human pancreatic ductal adenocarcinoma (PDAC) cells. Previous literature has suggested that consumption of fish oil is associated with lower risk of pancreatic cancer. In this study, we investigated the anti-cancer effects of docosahexaenoic acid (DHA) in human PDAC cells in vitro and in vivo. Omega-3 polyunsaturated fatty acids (PUFAs) such as DHA and eicosapentaenoic acid (EPA) significantly inhibited the proliferation of human PDAC cells. The actions of DHA were evaluated through an induction of cell cycle arrest at G1 phase and noticed a decreased expression of cyclin A, cyclin E and cyclin B proteins in HPAF-II cells. Moreover, it was found that co-treatment of DHA and gemcitabine (GEM) effectively induced oxidative stress and cell death in HPAF-II cells. Interestingly, DHA leads to an increased oxidative glutathione /reduced glutathione (GSSG/GSH) ratio and induced cell apoptosis in HPAF-II cells. The findings in the study showed that supplementation of GSH or N-Acetyl Cysteine (NAC) could reverse DHA-mediated cell death in HPAF-II cells. Additionally, DHA significantly increased cellular level of cysteine, cellular NADP/NADPH ratio and the expression of cystathionase (CTH) and SLCA11/xCT antiporter proteins in HPAF-II cells. The action of DHA was, in part, associated with the inactivation of STAT3 cascade in HPAF-II cells. Treatment with xCT inhibitors, such as erastin or sulfasalazine (SSZ), inhibited the cell survival ability in DHA-treated HPAF-II cells. DHA also inhibited nucleotide synthesis in HPAF-II cells. It was demonstrated in a mouse-xenograft model that consumption of fish oil significantly inhibited the growth of pancreatic adenocarcinoma and decreased cellular nucleotide level in tumor tissues. Furthermore, fish oil consumption induced an increment of GSSG/GSH ratio, an upregulation of xCT and CTH proteins in tumor tissues. In conclusion, DHA significantly inhibited survival of PDAC cells both in vitro and in vivo through its recently identified novel mode of action, including an increment in the ratio of GSSG/GSH and NADP/NADPH respectively, and promoting reduction in the levels of nucleotide synthesis.