The biochemical basis of antioxidant therapy in critical illness

Effects of a Saccharomyces cerevisiae fermentation product-supplemented diet on circulating immune cells and oxidative stress markers of dogs

Feeding Saccharomyces cerevisiae fermentation product (SCFP) has previously altered fecal microbiota, fecal metabolites, and immune function of adult dogs. The objective of this study was to investigate measures of skin and coat health, changes in circulating immune cell numbers and activity, antioxidant status, and oxidative stress marker concentrations of healthy adult dogs fed a SCFP-supplemented extruded diet. Sixteen adult English Pointer dogs (8 M, 8 F; mean age = 6.7 ± 2.1 yr; mean BW = 25.9 ± 4.5 kg) were used in a randomized crossover design study. All dogs were fed a control diet for 4 wk, then randomly assigned to either the control or SCFP-supplemented diet (0.13% of active SCFP) and fed to maintain BW for 10 wk. A 6-wk washout preceded the second 10-wk experimental period with dogs receiving opposite treatments. After baseline/washout and treatment phases, skin and coat were scored, and pre and postprandial blood samples were collected. Transepidermal water loss (TEWL), hydration status, and sebum concentrations were measured (back, inguinal, ear) using external probes. Oxidative stress and immune cell function were measured by ELISA, circulating immune cell percentages were analyzed by flow cytometry, and mRNA expression of oxidative stress genes was analyzed by RT-PCR. Change from baseline data was analyzed using the Mixed Models procedure of SAS 9.4. Sebum concentration changes tended to be higher (P < 0.10; inguinal, ear) in SCFP-fed dogs than in controls. TEWL change was lower (P < 0.05) on the back of controls, but lower (P = 0.054) on the ear of SCFP-fed dogs. Delayed-type hypersensitivity response was affected by diet and time post-inoculation. Other skin and coat measures and scores were not affected by diet. Changes in unstimulated lymphocytes and stimulated IFN-γ secreting T cells were lower (P < 0.05) in SCFP-fed dogs, while changes in stimulated T cells were lower (P < 0.05) in control-fed dogs. Upon stimulation, the percentage of cytotoxic T cells delta trended lower (P < 0.10) in SCFP-fed dogs. Change in serum superoxide dismutase concentrations was higher (P < 0.05) and change in catalase mRNA expression was lower (P < 0.05) in SCFP-fed dogs. All other measurements of immune cell populations, oxidative stress markers, and gene expression were unaffected by treatment. In conclusion, our data suggest that SCFP positively impacts indicators of skin and coat health of dogs, modulates immune responses, and enhances some antioxidant defense markers.

Targeted antioxidants as therapeutics for treatment of pneumonia in the elderly

Community acquired pneumonia is a leading cause of mortality in the United States. Along with predisposing comorbid health status, age is an independent risk factor for determining the outcome of pneumonia. Research over the last few decades has contributed to better understanding the underlying immunodysregulation and imbalanced redox homeostasis tied to this aged population group that increases susceptibility to a wide range of pathologies. Major approaches include targeting oxidative stress by reducing ROS generation at its main sources of production which includes the mitochondrion. Mitochondria-targeted antioxidants have a number of molecular strategies that include targeting the biophysical properties of mitochondria, mitochondrial localization of catalytic enzymes, and mitigating mitochondrial membrane potential. Results of several antioxidant studies both in vitro and in vivo have demonstrated promising potential as a therapeutic in the treatment of pneumonia in the elderly. More human studies will need to be conducted to evaluate its efficacy in this clinical setting.

Antioxidants reduce oxidative stress in follicular fluid of aged women undergoing IVF

BACKGROUND

The status characterized by the imbalance between pro-oxidants and antioxidants molecules, defined as oxidative stress, has been suggested to be involved in the pathogenesis of subfertility in females. This study aims to evaluate the impact of a complete micronutrients supplementation on oxidative stress levels in follicular microenvironment as well as on in vitro fertilization (IVF) outcome.

METHODS

This preliminary study was conducted between January 2014 and July 2015 at the Siena University Hospital Infertility Clinic. Serum and follicular fluid were collected from infertile women aged > 39 years who underwent two in vitro fertilization cycles: in the first cycle they were treated with GnRH-antagonist protocol and gonadotropins for controlled ovarian hyperstimulation, whereas in the second cycle ovarian stimulation protocol was associated to micronutrients supplementation, starting three months earlier. Protein oxidation levels and total antioxidant capacity in serum and in follicular fluid were evaluated in IVF cycles with or without micronutrients supplementation. Differences in IVF outcome parameters were statistically evaluated.

RESULTS

Two-dimensional electrophoresis analyses demonstrated that when patients assumed micronutrients before IVF cycles, follicular fluid and serum proteins were protected from oxidative damage. Comparable results were obtained when total antioxidant capacity was measured. Moreover, the mean number of good quality oocytes retrieved when patients received micronutrients supplementation was significantly increased.

CONCLUSION

The additional treatment with micronutrients, starting three months before IVF cycles, protects the follicular microenvironment from oxidative stress, thus increasing the number of good quality oocytes recovered at the pick up.

Transcriptional reprogramming of metabolic pathways in critically ill patients

Background

Critical illness causes a shift away from mitochondrial metabolism towards a greater dependence on glycolysis. This metabolic shift is thought to be associated with lactic acidosis, organ dysfunction and poor clinical outcomes. The current paradigm is that low oxygen supply causes regional hypoxia, which in turn drives such a metabolic shift. In this study, we evaluated whether the shift towards glycolysis can also occur in cells where oxygen supply is plentiful.

Methods

We used circulating blood cells from non-hypoxic critically ill patients (n = 47) as a model to study cellular metabolism in a normal oxygen milieu. We measured the transcriptomic profiles of canonical metabolic pathways in these cells and compared them to cells obtained from healthy controls (n = 18).

Results

Transcriptomic profiling revealed a significant reprogramming of metabolic pathways during critical illness. In well-oxygenated cells, there was a reduced expression of tricarboxylic acid cycle genes and genes associated with pyruvate entry into the mitochondria suggesting decreased mitochondrial oxidation. In contrast, glycolysis was accelerated, as reflected by an up-regulation of genes coding for enzymes of early and late glycolytic pathway that were associated with increased lactate production. The pentose phosphate pathway genes for NADPH production were also up-regulated suggesting enhanced antioxidant production during increased oxidative stress.

Conclusions

Contrary to the established paradigm, aerobic glycolysis does occur in non-hypoxic cells during critical illness and its occurrence may represent an adaptive strategy common to cells under increased oxidative stress. Further study of this previously under-recognized metabolic phenomenon might identify novel drug target for antioxidant therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s40635-016-0094-1) contains supplementary material, which is available to authorized users.

Protein modification as oxidative stress marker in follicular fluid from women with polycystic ovary syndrome: the effect of inositol and metformin

PURPOSE

The purpose of this study was to evaluate the oxidative stress status (OS) of follicular fluid (FF) and the oocyte quality in women with polycystic ovary syndrome (PCOS) undergoing different ovarian stimulation protocols.

METHODS

FF samples were collected after gonadotropin administration in association or not with metformin or D-chiro-inositol (DCI). OS status was then evaluated by checking the follicular fluid protein oxidation profile after specific labeling of aminoacidic free-SH groups, and two-dimensional electrophoresis followed by qualitative and semiquantitative analysis. Oocyte quality was assessed by international morphological criteria.

RESULTS

Our data indicated that both treatments, even if to different extent, recovered a significantly high level of free-SH groups in FF proteins of PCOS women clearly indicating a decrease of OS level with respect to that found in FF samples from gonadotropins alone treated women. A higher number of good quality MII oocytes was also observed in DCI (P < 0.05) or metformin (P < 0.05) study groups in comparison to untreated control group.

CONCLUSION

A natural supplement and a drug both showed a statistically significant positive effect on follicular milieu by decreasing the oxidative damage on FF proteins, as well as in recovering good quality oocytes.

The need for evidence based nutritional guidelines for pediatric acute lymphoblastic leukemia patients: acute and long-term following treatment

High survival rates for pediatric leukemia are very promising. With regard to treatment, children tend to be able to withstand a more aggressive treatment protocol than adults. The differences in both treatment modalities and outcomes between children and adults make extrapolation of adult studies to children inappropriate. The higher success is associated with a significant number of children experiencing nutrition-related adverse effects both in the short and long term after treatment. Specific treatment protocols have been shown to deplete nutrient levels, in particular antioxidants. The optimal nutrition prescription during, after and long-term following cancer treatment is unknown. This review article will provide an overview of the known physiologic processes of pediatric leukemia and how they contribute to the complexity of performing nutritional assessment in this population. It will also discuss known nutrition-related consequences, both short and long term in pediatric leukemia patients. Since specific antioxidants have been shown to be depleted as a consequence of therapy, the role of oxidative stress in the pediatric leukemia population will also be explored. More pediatric studies are needed to develop evidence based therapeutic interventions for nutritional complications of leukemia and its treatment.

Protein modification as oxidative stress marker in normal and pathological human seminal plasma

OBJECTIVE

Our study aims to assess the oxidative stress status of seminal plasma from normozoospermic, azoospermic, and leukocytospermic males, since abnormal sperm and leukocytes in human ejaculates are the main source of reactive oxygen species (ROS) which lead to oxidative damages. For this purpose we applied a biochemical approach to the assessment of the oxidative stress status by using two-dimensional (2D) electrophoresis to check the level of protein oxidation after specific labeling of free thiol (-SH) groups.

METHODS

Seminal plasma samples from normal and pathological males were analyzed by a luminol-based chemiluminescent assay. The same samples after specific labeling of free -SH groups with 3-N-maleimidopropionyl biocytin, were analyzed by 2D electrophoresis and computer-assisted semiquantitative determination of the amount of free -SH groups.

RESULTS

Using a standard chemiluminescence assay, we demonstrated a high, low and normal level of ROS, respectively, in seminal plasma from leukocytospermic, azoospermic, and normozoospermic subjects. By 2D electrophoresis and streptavidin blotting of specifically labeled free -SH groups of proteins, we detected in the same samples a higher level of oxidated -SH groups comparable between azoospermic and leukocytospermic samples, whereas a significantly higher level of free -SH groups was detected in normozoospermic subjects.

DISCUSSION

Our results demonstrated that a pathological oxidative stress status in seminal plasma may be revealed by the levels of the protein free -SH groups, both in the presence or absence of cells.

Nutrition, immunology, and genetics: future perspectives

This review surveys some of the areas in which nutrients have been shown to have an impact on specific immune functions, the use of molecular and genetic tools to study molecular responses to dietary factors,and the metabolic consequences of food. It also explores the relationships between nutrient molecules, genetic polymorphisms, and the biological system as a whole, while providing a short introduction to nutrition immunology, nutrient-gene interactions and the novel technologies employed in nutrigenomics and nutrigenetics research.

Molecular mechanisms behind clinical benefits of intensive insulin therapy during critical illness: glucose versus insulin

High blood glucose levels have been associated with morbidity and poor outcome in critically ill patients, irrespective of underlying pathology. In a large, randomised, controlled study the use of insulin therapy to maintain normoglycaemia for at least a few days improved survival and reduced morbidity of patients who are in a surgical intensive care unit (ICU). Since the publication of this landmark study, several other investigators have provided support for, whereas others have questioned, the beneficial effects of intensive insulin therapy. In this review, we discuss the investigated potential molecular mechanisms behind the clinical benefits of intensive insulin therapy. We first describe the molecular origin of hyperglycaemia and the impact of the therapy on insulin sensitivity. Next, the molecular basis of glucose toxicity in critical illness and the impact of intensive insulin therapy hereon are described, as well as other non-glucose-toxicity-related metabolic effects of intensive insulin therapy.

Transsulfuration pathway defects and increased glutathione degradation in severe acute pancreatitis

Glutathione depletion is a consistent feature of the progression of mild to severe acute pancreatitis. In this study, we examined the temporal relationship between cysteine, homocysteine, and cysteinyl-glycine levels; total reduced erythrocyte glutathione; gamma-glutamyl transpeptidase activity; and disease severity. Initially, cysteine concentration was low, at levels similar to those of healthy controls. However, glutathione was reduced whilst cysteinyl glycine and gamma-glutamyl transpeptidase activity were increased in both mild and severe attacks. As the disease progressed, glutathione and cysteinyl glycine were further increased in mild attacks and cysteine levels correlated with homocysteine (r = 0.8, P < 0.001) and gamma-glutamyl transpeptidase activity (r = 0.75, P < 0.001). The progress of severe attacks was associated with glutathione depletion, reduced gamma-glutamyl transpeptidase activity, and increased cysteinyl glycine that correlated with glutathione depletion (r = 0.99, P = 0.01). These results show that glutathione depletion associated with severe acute pancreatitis occurs despite an adequate cysteine supply and could be attributed to heightened oxidative stress coupled to impaired downstream biosynthesis.

L-alanyl-L-glutamine-supplemented parenteral nutrition decreases infectious morbidity rate in patients with severe acute pancreatitis

BACKGROUND

The effect of parenteral GLN on recovery from severe acute pancreatitis has not been thoroughly investigated. The aims of this study were to determine whether parenteral GLN improves nutrition status and immune function, and to determine its ability to reduce morbidity and mortality in patients with this condition.

METHODS

In a randomized clinical trial, 44 patients with severe acute pancreatitis were randomly assigned to receive either standard PN (n = 22) or l-alanyl-l-glutamine-supplemented PN (n = 22) after hospital admission. Nitrogen balance, counts of leukocytes, total lymphocytes, and CD4 and CD8 subpopulations, and serum levels of immunoglobulin A, total protein, albumin, C-reactive protein, and serum interleukin (IL)-6 and IL-10 were measured on days 0, 5, and 10. Hospital stay, infectious morbidity, and mortality were also evaluated.

RESULTS

Demographics, laboratory characteristics, and pancreatitis etiology and severity at entry to the study were similar between groups. The study group exhibited significant increases in serum IL-10 levels, total lymphocyte and lymphocyte subpopulation counts, and albumin serum levels. Nitrogen balance also improved to positive levels in the study group and remained negative in the control group. Infectious morbidity was more frequent in the control group than in the study group. The duration of hospital stay was similar between groups, as was mortality.

CONCLUSION

The results suggest that treatment of patients with GLN-supplemented PN may decrease infectious morbidity rate compared with those who treated with nonenriched PN.

The role of nutrients in modulating disease

The role of nutrition in the management of diseases has often centred on correcting apparent nutrient deficiencies or meeting estimated nutritional requirements of patients. Nutrition has traditionally been considered a supportive measure akin to fluid therapy and rarely it has been considered a primary means of ameliorating diseases. Recently, however, further understanding of the underlying mechanisms of various disease processes and how certain nutrients possess pharmacological properties have fuelled an interest in exploring how nutritional therapies themselves could modify the behaviour of various conditions. Nutrients such as omega-3 fatty acids, antioxidants and certain amino acids such as arginine and glutamine have all been demonstrated to have at least the potential to modulate diseases. Developments in the area of critical care nutrition have been particularly exciting as nutritional therapies utilising a combination of approaches have been shown to positively impact outcome beyond simply proving substrate for synthesis and energy. Application of certain nutrients for the modulation of diseases in veterinary patients is still in early stages, but apparent successes have already been demonstrated, and future studies are warranted to establish optimal approaches. This review describes the rationale of many of these approaches and discusses findings both in human beings and in animals, which may guide future therapy.

Glutamine in critical care: current evidence from systematic reviews

Glutamine, the most abundant amino acid in the body, is thought to become conditionally essential in critical illness. Some of the important roles for glutamine are as a carrier for inter-organ N, a preferred fuel for enterocytes and cells of the immune system, a substrate for renal NH3 formation and a precursor for glutathione. Mechanisms by which glutamine could improve recovery include attenuating oxidant damage and inflammatory cytokine production, reducing gut bacterial translocation and improving N balance. The present systematic review has found trends to suggest that parenteral and enteral glutamine supplementation reduce mortality, the development of infection and organ failure in critical illness. Trials of parenteral nutrition containing glutamine with patients after elective surgery also suggest reduction of infection, but it is unlikely that glutamine-containing parenteral nutrition would be used for such patients. The evidence base is limited by the quality of the reported trials and the suggestion that there is publication bias, with trials suggesting reduced infection being more likely to be published.