Changes in macrophage and lymphocyte functions in guinea-pigs after different amounts of vitamin E ingestion

Water-Soluble Vitamin E-Tocopheryl Phosphate

The hydrophobicity of vitamin E poses transport and metabolic challenges to regulate its bioavailability and to prevent its accumulation in lipid-rich tissues such as adipose tissue, brain, and liver. Water-soluble precursors of vitamin E (α-tocopherol, αT), such as its esters with acetate (αTA), succinate (αTS), or phosphate (αTP), have increased solubility in water and stability against reaction with free radicals, but they are rapidly converted during their uptake into the lipid-soluble vitamin E. Therefore, the bioavailability of these precursors as intact molecules is low; nevertheless, at least for αTS and αTP, the recent research has revealed unique regulatory effects on signal transduction and gene expression and the modulation of cellular events ranging from proliferation, survival/apoptosis, lipid uptake and metabolism, phagocytosis, long term potentiation, cell migration, telomere maintenance, and angiogenesis. Moreover, water-soluble derivatives of vitamin E including some based on αTP are increasingly used as components of nanocarriers for enhanced and targeted delivery of drugs and other molecules (vitamins, including αT and αTP itself, vitamin D3, carnosine, caffeine, docosahexaenoic acid (DHA), insulin) and cofactors such as coenzyme Q10. In this review, the chemical characteristics, transport, metabolic pathways, and molecular mechanisms of action of αTP in cells and tissues are summarized and put into perspective with its possible role in the prevention of a number of diseases.

α-Tocopheryl Phosphate Induces VEGF Expression via CD36/PI3Kγ in THP-1 Monocytes

The CD36 scavenger receptor binds several ligands and mediates ligand uptake and ligand-dependent signal transduction and gene expression, events that may involve CD36 internalization. Here we show that CD36 internalization in THP-1 monocytes is triggered by α-tocopherol (αT) and more strongly by α-tocopheryl phosphate (αTP) and EPC-K1, a phosphate diester of αTP and L-ascorbic acid. αTP-triggered CD36 internalization is prevented by the specific covalent inhibitor of selective lipid transport by CD36, sulfo-N-succinimidyl oleate (SSO). Moreover, SSO inhibited the CD36-mediated uptake of 14C-labelled αTP suggesting that αTP binding and internalization of CD36 is involved in cellular αTP uptake, whereas the uptake of αT was less affected. Similar to that, inhibition of selective lipid transport of the SR-BI scavenger receptor resulted mainly in reduction of αTP and not αT uptake. In contrast, uptake of αT was mainly inhibited by Dynasore, an inhibitor of clathrin-mediated endocytosis, suggesting that the differential regulatory effects of αTP and αT on signaling may be influenced by their different routes of uptake. Interestingly, αTP and EPC-K1 also reduced the neutral lipid content of THP-1 cells and the phagocytosis of fluorescent Staphylococcus aureus bioparticles. Moreover, induction of the vascular endothelial growth factor (VEGF) promoter activity by αTP occurred via CD36/PI3Kγ/Akt, as it could be inhibited by specific inhibitors of this pathway (SSO, Wortmannin, AS-605240). These results suggest that αTP activates PI3Kγ/Akt signaling leading to VEGF expression in monocytes after binding to and/or transport by CD36, a receptor known to modulate angiogenesis in response to amyloid beta, oxLDL, and thrombospondin. J. Cell. Biochem. 118: 1855-1867, 2017. © 2017 Wiley Periodicals, Inc.

Comparative study of peritoneal macrophage functions in mice receiving lethal and non-lethal doses of LPS

In previous studies, we have observed changes in several functions of peritoneal macrophages from female BALB/c mice with lethal endotoxic shock caused by intraperitoneal injection of Escherichia coli O55:B5 lipopolysaccharide (LPS; 100 mg/kg), which were associated with a high production of superoxide anion and tumor necrosis factor alpha (TNF-α). In the present work, both a lethal dose (250 mg/kg) and a non-lethal dose (100 mg/kg) of LPS were used in female Swiss mice. In peritoneal macrophages, the following functions were studied at 2, 4, 12 and 24 h after LPS injection: adherence to substrate, chemotaxis, ingestion of particles, and superoxide anion and TNF-α production. In both groups, the results showed a stimulation of adherence, ingestion and superoxide production as well as a decrease of chemotaxis, whereas TNF-α could not be detected in either of the two groups. These effects were more evident with the 250 mg/kg dose, especially as regards superoxide anion production, which was higher in the animals treated with a lethal dose of LPS.

Fat Soluble Vitamins and Immune System: An Overview

The immune system guards against invasion by foreign microrganisms and molecules. In this way, it protects from fatal illnesses and communicable diseases. Its proper functioning is fundamental for survival.

Research has demonstrated that proper nutrition plays a crucial role in the prevention of chronic disease. Protein-energy malnutrition is associated with a significant impairment of cell-mediated immunity, phagocyte function, the complement system, secretory immunoglobulin A antibody concentrations, and cytokine production. Deficiency of single nutrients also results in altered immune responses; this is observed even when the deficiency state is relatively mild. Of the micronutrients, zinc, selenium, iron, copper, vitamins A,C,E and B, and folic acid have important influences on the immune response.

It is now apparent that vitamin E and β-carotene have more subtle roles and that deficient dietary intake of these vitamins increases susceptibility to certain cancers and cardiovascular disease. This reflects, in part, the antioxidant properties of the vitamins and their ability to reduce free radical-mediated damage to DNA, proteins and lipid membranes. These findings have considerable practical and public health significance. The aim of this review is to give an up-to date account of the roles of selected fat-soluble vitamins in health and disease.

Modulation of ROS levels in fibroblasts by altering mitochondria regulates the process of wound healing

Mitochondria are the major source of reactive oxygen species (ROS) in fibroblasts which are thought to be crucial regulators of wound healing with a potential to affect the expression of nuclear genes involved in this process. ROS generated by mitochondria are involved in all stages of tissue repair process but the regulation of ROS-generating system in fibroblasts still remains poorly understood. The purpose of this study was to better understand molecular mechanisms of how the regulation of ROS levels generated by mitochondria may influence the process of wound repair. Cybrid model system of mtDNA variations was used to study the functional consequences of altered ROS levels on wound healing responses in a uniform nuclear background of cultured ρ(0) fibroblasts. Mitochondrial ROS in cybrids were modulated by antioxidants that quench ROS to examine their ability to close the wound. Real-time PCR arrays were used to investigate whether ROS generated by specific mtDNA variants have the ability to alter expression of some key nuclear-encoded genes central to the wound healing response and oxidative stress. Our data suggest levels of mitochondrial ROS affect expression of some nuclear encoded genes central to wound healing response and oxidative stress and modulation of mitochondrial ROS by antioxidants positively affects in vitro process of wound closure. Thus, regulation of mitochondrial ROS-generating system in fibroblasts can be used as effective natural redox-based strategy to help treat non-healing wounds.

Vitamin E and wound healing: an evidence-based review

Vitamin E has been demonstrated to modulate cellular signalling, gene expression and affect wounds infected with methicillin-resistant Staphylococcus aureus (MRSA), thus influencing wound healing. This evidence-based review aimed to identify and evaluate current research assessing the properties of vitamin E in relation to wound healing, through its role as an antioxidant and its influence on connective tissue growth factor (CTGF), MRSA and gene transcription. Literature dated from 1996 to 2012, published in English, involving either animals or adult humans with an acute or chronic wound were included. The databases that contained relevant articles were narrowed down to four, and a total of 33 identified studies were included. The literature review revealed that there is a significant dearth of robust studies establishing the effects of vitamin E on wound healing, and further research is clearly warranted.

Vitamin E restriction in the diet enhances phagocytic activation by dichloroacetate and trichloroacetate in mice

The effects of a vitamin E-restricted diet on the induction of phagocytic activation by dichloroacetate (DCA) and trichloroacetate (TCA) was investigated. Groups of B6C3F1 male mice were either kept on standard diet (Std diet group) or diet that had the vitamin provided only by its natural ingredients (Low-E diet group). The animals in each diet group were administered 77 mg of DCA or TCA/ kg/day, or 5 ml/kg water (controls), by gavage, for 13 weeks. Thereafter, peritoneal lavage cells (PLC) were assayed for superoxide anion (SA), tumor necrosis factor (TNF)-α, and myeloperoxidase (MPO), as well as for the activities of the anti-oxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). SA and TNFα production, as well as MPO, SOD, CAT and GSH-Px activities were significantly increased in the cells from the Low-E diet group treated with the compounds as compared with cells from hosts in the Std-diet group that received the corresponding treatments. The results indicate that consumption of a Vitamin E-restricted diet enhances the induction of phagocytic activation by DCA and TCA, a mechanism that was previously suggested to be an initial adaptive/protective response against the compounds long-term effects.

Vitamin E ingestion improves several immune functions in elderly men and women

The effects of diet supplementation with the antioxidant vitamin E (200 mg daily) on several blood neutrophil, lymphocyte and natural killer cell functions have been investigated in healthy elderly men and women before supplementation, after 3 months of supplementation and 6 months after the end of supplementation (post-supplementation). In parallel, samples of healthy adult men and women were used as age controls. In elderly men and women, an impairment of immune functions was observed in comparison with the respective adult controls and the intake of vitamin E resulted in a significant enhancement of immune parameters in both elderly men and women, bringing their values close to those in the adults. These effects were not found in post-supplementation samples in several but not in all functions. The present findings suggest that supplementation with vitamin E can produce an improvement of immune functions and therefore of health in aged people.

Effects of dietary fish oil and vitamin E supplementation on canine lymphocyte proliferation evaluated using a flow cytometric technique

Lymphocyte proliferation and peripheral blood mononuclear cell (PBMC) production of PGE(2) were assayed in 15 healthy dogs fed a basal diet supplemented with either sunflower oil (Group Sunflower oil), sunflower oil and menhaden fish oil (Group Fish oil), or sunflower oil and menhaden fish oil plus alpha-tocopherol acetate for 12 weeks (Group Fish oil + E). Lymphocyte proliferation was determined by a flow cytometric technique utilizing the fluorochrome carboxyfluorescein diacetate succinimidyl ester (CFSE). The PBMC supernatant PGE(2) concentration was assayed using a competitive enzyme-linked immunoassay. Group Fish oil had a significant decrease in lymphocyte proliferation at week 12. PBMC production of PGE(2) was decreased in all three groups but only significantly reduced in groups receiving fish oil supplementation. Based on these results, this level of fish oil supplementation appears to suppress the lymphoproliferative response in healthy, young dogs but this response can be attenuated by high levels of dietary vitamin E supplementation. Furthermore, fish oil-induced reduction in lymphocyte proliferation appears to manifest through a PGE(2)-independent mechanism and is not associated with increased lipid peroxidation.

Early maternal deprivation and neonatal single administration with a cannabinoid agonist induce long-term sex-dependent psychoimmunoendocrine effects in adolescent rats

Maternal deprivation [24h on postnatal day 9] might represent an animal model of schizophrenia and behavioural and neurochemical alterations observed in adulthood may be mediated by hippocampal impairments induced by abnormally increased glucocorticoids due to neonatal stress. We aimed to provide new data for psychoimmunoendocrine characterization of this animal model by evaluating its effects in adolescent rats of both genders. In previous studies we found that cannabinoid compounds counteracted the enhanced impulsivity of maternally deprived animals and that the cannabinoid receptor agonist WIN 55,212-2 showed neuroprotective properties in neonatal rats. So, we hypothesised that this compound could counteract at least some of the detrimental effects that we expected to find in maternally deprived animals. Accordingly, the drug was administered immediately after the maternal deprivation period. Maternally deprived males showed significantly decreased motor activity in the holeboard and the plus-maze. The cannabinoid agonist induced, exclusively in males, a significant anxiogenic-like effect, which was reversed by maternal deprivation. In the forced swimming test, both treatments independently induced depressive-like responses. Maternal deprivation reduced immunological function whereas the drug exerted tissue-dependent effects on the immune parameters analysed. Maternally deprived females showed reduced corticosterone levels whereas the cannabinoid agonist increased hormone concentration in all groups. In general, the results show detrimental effects of both treatments as well as intriguing interactions, notably in relation to emotional behaviour and certain immunological responses.

Dietary supplementation with antioxidants improves functions and decreases oxidative stress of leukocytes from prematurely aging mice

OBJECTIVES

Aging is accompanied by chronic inflammation and oxidative stress, which lead to a marked impairment of immune function and therefore increased mortality. This study assessed the effect of dietary supplementation, for 15 wk, with 5% and 20% (w/w) of biscuits enriched with nutritional doses of vitamins C and E, zinc, selenium, and beta-carotenes on function and oxidative stress parameters of peritoneal leukocytes from middle-aged, prematurely aging mice (PAM) and non-prematurely aging mice (NPAM).

METHODS

After supplementation we measured leukocyte functions (adherence, chemotaxis, phagocytosis, intracellular reactive oxygen species levels, lymphoproliferation, natural killer activity, and interleukin-2 release), antioxidant defenses (superoxide dismutase, glutathione peroxidase, and reduced glutathione), oxidant compounds (extracellular O(2)(-), glutathione disulfide, glutathione disulfide/reduced glutathione ratio, tumor necrosis factor-alpha, nitric oxide, and prostaglandin E(2)), and lipid and DNA oxidative damage, measured by malondialdehyde and 8-oxo,7,8-dihydro-2'-deoxyguanosine levels, respectively.

RESULTS

In general, leukocyte functions were improved and redox homeostasis was restored after intake of antioxidants. In consequence, malondialdehyde and 8-oxo,7,8-dihydro-2'-deoxyguanosine in PAM and NPAM were strikingly decreased after 5% and 20% supplementation (malondialdehyde, P < 0.001 in PAM; P < 0.01 in NPAM after both treatments; 8-oxo,7,8-dihydro-2'-deoxyguanosine, P < 0.01 after 5% supplementation and P < 0.001 after 20% supplementation in PAM and NPAM). Moreover, the effect of the antioxidants was stronger in PAM than in NPAM, and 20% supplementation was more effective than 5%.

CONCLUSION

Our data suggest that improvement of leukocyte function and restoration of redox balance after consumption of adequate levels of antioxidants from adulthood may be useful to attain healthy aging, especially in animals with premature aging.

Improvement of leukocyte functions in prematurely aging mice after five weeks of diet supplementation with polyphenol-rich cereals

OBJECTIVE

We investigated the beneficial effects of diet supplementation with two types of cereals naturally rich in polyphenolic compounds on several functions of peritoneal leukocytes from prematurely aging mice (PAM).

METHODS

Two-hundred sixty healthy mice, 8 wk of age, were recruited and their behavioral responses were tested in a simple T-maze to identify PAM. Then the mice were fed a diet supplemented with 20% (wt/wt) of two different cereal fractions, named B (wheat germ) and C (buckwheat flour), rich in polyphenols (gallic acid, catechin, p-hydroxybenzoic acid, vanillic acid, p-coumaric acid, sinapic acid, ferulic acid, quercetin, and rutin), or a standard diet (controls) for 5 wk. Several parameters of innate (adherence to tissues, chemotaxis, phagocytosis, microbicidal capacity, and natural killer activity) and acquired immune (lymphoproliferation and interleukin-2 release) responses were measured.

RESULTS

The PAM control group showed worse immune functions (P < 0.001 to 0.05) compared with the non-PAM control group. The PAM group that received cereal B showed increases in phagocytosis (P < 0.01), microbicidal activity (P < 0.001 to 0.01), natural killer activity (P < 0.001) and lymphoproliferation in response to lipopolysaccharide (P < 0.01) and interleukin-2 release (P < 0.001), and the PAM group that received cereal C showed a similar pattern, with increases in macrophage chemotaxis (P < 0.01), phagocytosis (P < 0.01), microbicidal activity (P < 0.001 to 0.01), natural killer activity (P < 0.01), lymphoproliferative response to concanavalin A and lipopolysaccharide (P < 0.001), and interleukin-2 release (P < 0.001).

CONCLUSIONS

Dietary supplementation with polyphenol-rich cereals appears to have a protective effect on immune cell functions in mice with premature senescence. Thus, regular intake of these compounds could delay normal aging and improve quality of life.

Improvement of leukocyte functions in young prematurely aging mice after a 5-week ingestion of a diet supplemented with biscuits enriched in antioxidants

In our previous studies, diet supplementation with therapeutic thiolic antioxidants improved the function of peritoneal leukocytes from mice, especially in adult prematurely aging mice (PAM). In the present work, we have studied the effects of ingestion during 5 weeks of a diet supplemented with 20% (wt/wt) of biscuits enriched with antioxidants (vitamin C, vitamin E, beta-carotene, zinc, and selenium) on several immune functions of peritoneal leukocytes from young PAM. The results show that, in macrophages, chemotaxis and phagocytosis as well as the intracellular free radical levels, which are depressed in PAM in comparison with the control nonprematurely aging mice (NPAM), increase after supplementation, especially in the PAM. An increase also occurs in lymphocyte chemotaxis, proliferative response to the mitogen concanavalin A, and interleukin-2 release, as well as in natural killer cell activity. However, the release of tumor necrosis factor-alpha, which increases with aging, decreases after 5 weeks of supplementation. As a well preserved function of the immune system is an excellent marker of health and longevity, the improvement of leukocyte functions after ingestion of the present diet suggests that this antioxidant supplementation may be useful for the preservation of health and functional longevity in aging populations.

Changes with ageing in several leukocyte functions of male and female rats

The impairment of the immune system with aging, or 'immunosenescence', appears to contribute to the increased morbidity and mortality of aged subjects. T cell functions and Natural Killer activity seem to be the immune responses most affected by ageing. Since the immune system works more efficiently in females than in males, we have studied the changes of several immune functions with age in rats of both sexes. In addition, we have investigated if ovariectomy, a model of menopause in rats, produces a loss of this gender-related advantage. In the present work, the changes with age (2, 6, 12, 14, 18, 22 and 24 months old) in lymphocyte chemotaxis, T lymphoproliferative response to the mitogen ConA, IL-2 release and Natural Killer activity of cells from axillary nodes and spleen of male and female rats as well as of females ovariectomized at 12 months of age have been studied. An age-related decrease was found in all investigated functions, with a slightly different evolution depending on the immune organ and gender considered. In general, the data obtained show that a certain degree of immunosenescence takes place with age in rats, with males being less immunocompetent than intact age-matched females, but showing an immune response similar to that of ovariectomized animals.

Oil-in-water lipid emulsions: implications for parenteral and ocular delivering systems

Lipid emulsions (LEs) are heterogenous dispersions of two immiscible liquids (oil-in-water or water-in-oil) and they are subjected to various instability processes like aggregation, flocculation, coalescence and hence eventual phase separation according to the second law of thermodynamics. However, the physical stability of the LE can substantially be improved with help of suitable emulsifiers that are capable of forming a mono- or multi-layer coating film around the dispersed liquid droplets in such a way to reduce interfacial tension or to increase droplet-droplet repulsion. Depending on the concentrations of these three components (oil-water-emulsifier) and the efficiency of the emulsification equipments used to reduce droplet size, the final LE may be in the form of oil-in-water (o/w), water-in-oil (w/o), micron, submicron and double or multiple emulsions (o/w/o and w/o/w). The o/w type LEs (LE) are colloidal drug carriers, which have various therapeutic applications. As an intravenous delivery system it incorporates lipophilic water non-soluble drugs, stabilize drugs that tend to undergo hydrolysis and reduce side effects of various potent drugs. When the LE is used as an ocular delivery systems they increase local bioavailability, sustain the pharmacological effect of drugs and decrease systemic side effects of the drugs. Thus, the rationale of using LE as an integral part of effective treatment is clear. Following administration of LE through these routes, the biofate of LE associated bioactive molecules are somehow related to the vehicles disposition kinetics inside blood or eyeball. However, the LE is not devoid from undergoing various bio-process while exerting their efficacious actions. The purpose of this review is therefore to give an implication of LE for parenteral and ocular delivering systems.

Macrophage involvement for successful degeneration of apoptotic organs in the colonial urochordate Botryllus schlosseri

Apoptosis is an important tool for shaping developing organs and for maintaining cellular homeostasis. In the colonial urochordate Botryllus schlosseri, apoptosis is also the hallmark end point in blastogenesis, a cyclical and weekly developmental phenomenon. Then the entire old generation of zooids are eliminated (resorbed) by a process that lasts 24-36 h. Administration of the antioxidant butylated hydroxytoluene (BHT) resulted in resorption being arrested by 1-8 days on average. At high doses (2.5-15.0 mg BHT l(-1)) resorption was completed only after removal of BHT. Colonies that were not removed in time, died. In treated colonies, although DNA fragmentation was high, tissues and organs that would normally have died, survived, and the general oxidative levels of lipids were reduced. Blood vessels were widened, containing aggregates of blood cells with a significantly increased proportion of empty macrophage-like cells without inclusion. In colonies rescued from BHT treatment, resorption of zooids started immediately and was completed within a few days. We propose three possible mechanisms as to how BHT may affect macrophage activity: (1) by interrupting signals that further promote apoptosis; (2) through the respiratory burst initiated following a phagocytic stimulus; and (3) by reducing lipid oxidation and changing cell surface markers of target cells. Our results point, for the first time, to the role of phagocytic cells in the coordination of death and clearance signals in blastogenesis.

Effect of Vitamin E Supplementation on Various Functional Properties of Macrophages and Neutrophils Obtained from Weaned Piglets

Sixteen piglets were used to determine the effect of vitamin E supplementation on several functional properties of macrophages and neutrophils obtained from weaned piglets. Piglets, immediately following weaning, were assigned to one of three experimental groups: control (no vitamin E supplementation), low level of vitamin E supplementation (100 mg DL-alpha-tocopheryl acetate/kg diet) and high level of vitamin E supplementation (300 mg DL-alpha-tocopheryl acetate/kg diet). Supplementation of vitamin E lasted for a period of 36 days, following a 3-day adaptation period after weaning. Blood samples were collected on days 0, 12, 24 and 36 of the experimental period, monocytes/macrophages and neutrophils were isolated and the following parameters were determined in macrophages and neutrophils activated by phorbol myristate acetate: total cell-associated and membrane-bound urokinase plasminogen activator (u-PA) activity and superoxide anion production. Results showed that macrophages and neutrophils isolated from piglets that received supplemental vitamin E had higher (P < 0.05) total and membrane-bound u-PA activities as well as higher (P < 0.05) superoxide anion production compared with the values of the corresponding cells obtained from control piglets on day 12 of the experimental period. Both levels of vitamin E supplementation (low and high) were equally effective. In contrast, vitamin E supplementation had no effect (P > 0.05) on total and membrane-bound u-PA activities and superoxide anion production by porcine macrophages and neutrophils on days 24 and 36 of the experimental period. In conclusion, the low level of vitamin E supplementation is recommended for piglets for the first 2 weeks after weaning.

Regulation of macrophage function by the antioxidant N-acetylcysteine in mouse-oxidative stress by endotoxin

Changes in several functions of peritoneal macrophages from mice with oxidative stress caused by intraperitoneal injection of endotoxin (Escherichia coli lipopolysaccharide, LPS) (100 mg/kg), and associated with a high production of reactive oxygen species (ROS), have been observed in our previous studies. Antioxidants such as N-acetylcysteine (NAC) are free radical scavengers that improve and modulate the immune response, especially in oxidative stress situations. Therefore, in the present work, we have studied the effects of the administration of NAC (150 mg/kg i.p.) on different functions of peritoneal macrophages from Swiss mice suffering that oxidative stress, caused by LPS (100 mg/kg). NAC was injected 30 min after LPS injection, and the peritoneal macrophages were obtained at 2, 4, 12, and 24 h after endotoxin injection. The following functions, key stages of the phagocytic process, were studied: adherence to substrate, chemotaxis, ingestion of particles, and production of ROS (reactive oxygen species), as well as tumor necrosis factor (TNFalpha) release. The decrease in chemotaxis and the increase in adherence, ingestion, superoxide anion production, and TNFalpha release shown by macrophages from animals with oxidative stress were counteracted by NAC injection. These data suggest that NAC administration may be useful for the treatment of oxidative stress-linked endotoxic shock, modulating the function of macrophages, specifically in decreasing the production of ROS and of inflammatory cytokines such as TNFalpha.

A diet supplemented with thiolic anti-oxidants improves leucocyte function in two strains of prematurely ageing mice

1. According to previous studies, Swiss mice of the same age showed striking interindividual differences in behaviour when exposed to a T-maze test, with a slow performance being linked to an impaired immune function, hyperemotional response to stress and a shorter life span compared with mice that quickly explore the maze. These facts led us to propose the slow mice as a model of prematurely ageing mice (PAM). 2. In the present study, we investigated whether this prematurely ageing model could be found in other strains of mice, such as BALB/c mice, by analysing several lymphocytes functions, such as adherence, chemotaxis, proliferative response to the mitogen concanavalin A (Con A), interleukin (IL)-2 release and natural killer (NK) activity. In addition, we tested the probable beneficial effects on these functions of dietary supplementation with thioproline (TP) plus N-acetylcysteine (NAC; 0.1% w/w of each anti-oxidant) in female Swiss and BALB/c mice. 3. Our model of premature ageing, previously reported in Swiss mice, has also been reproduced in the inbred BALB/c mouse strain, in which PAM showing an immunosenescence in several lymphocyte functions, such as lower chemotaxis, proliferative response to Con A, IL-2 release and NK activity, as well as higher adherence, were observed. A short-term (5 week) ingestion of TP + NAC by female Swiss and BALB/c mice improved leucocyte function, increasing chemotaxis, the proliferative response to Con A, IL-2 release and NK activity and decreasing the adherence of lymphocytes. These effects are greatest in cells from PAM of both strains. 4. In conclusion, our model of premature ageing has been reproduced in an inbred strain. In addition, the ingestion of a diet supplemented with two thiolic anti-oxidants, such as NAC and TP, has been shown to be beneficial to the immune response in PAM.

Serum neopterin monitoring and vitamin E-modified, regenerated hemodialyzer membrane influence on biocompatibility

The exposure of blood to hemodialysis membranes results in numerous phenomena and/or complications in hemodialyzed patients, which have an influence on the quality of life (QOL) of those patients. A vitamin E-modified regenerated cellulose membrane (E-membrane) was developed to act as a scavenger for reactive oxygen species causing complications in hemodialysis patients. Neopterin (NEOP) is a metabolite derived from guanosine triphosphate with the production and release of NEOP being induced in monocytes and macrophages by cytokines such as interferon-gamma (IFN-gamma). Serum neopterin levels are shown to be a reactive marker of bioincompatibility of dialysis membranes in hemodialysis patients. The following report evaluates the usefulness of serum NEOP as a marker for the biocompatibility of the E-membrane hemodialyzer in a clinical study. In the clinical study, where extracorporeal ultrafiltration strategies with E-membranes were employed, the serum levels of NEOP were lower than those in patients using cellulose triacetate membranes (C-membranes). In the long-term evaluation of the biocompatibility of E- and C-membranes, the increase of serum neopterin levels in the C-membrane was higher than those in the E-membrane. In conclusion, the evaluation of serum neopterin levels during hemodialysis shows that the E-membrane has a good biocompatibility in hemodialyzed patients.

Parenteral lipid emulsions and phagocytic systems

Lipid emulsions (LE) for parenteral use are complex emulsions containing fatty acids, glycerol, phospholipids and tocopherol in variable amounts and concentrations. In clinical practice, LE have been employed for more than 30 years. Fatty acids may have different impacts on phagocytic cells according to their structure. Experimental and clinical studies have consistently shown that LE modify monocyte/macrophage and polymorphonuclear phagocytosis. The inhibitory effect of LE on the functional activity of the phagocytic system, although still clinically controversial, may have a harmful impact because total parenteral nutrition with lipids may be recommended in hypercatabolic conditions where inflammation and infection are present. LE based on triglycerides containing long chain fatty acids (termed long chain triglycerides or LCT) are the main parenteral fat source and are typically rich in n-6 polyunsaturated fatty acids. They may have adverse effects on the immune system, especially when given in high doses over a short period of time. However when administered properly they can be used safely. LE containing medium chain triglycerides (MCT) may have some advantages because of their positive effects on polymorphonuclear cells, macrophages, and cytokine production, particularly in critically ill or immunocompromised patients. New parenteral LE containing n-3 polyunsaturated fatty acids or monounsaturated olive oil are already available in Europe. Judicious use of these new LE is mandatory especially relating on their potential impact on the immune system. New experimental and clinical studies are required to further establish the role of LE in clinical nutrition.