[Oxygen and the superoxide anion. Modulation of NADPH oxidase?]

Oxidative stress which results from an imbalance between oxidant production and antioxidant defense mechanisms can promote modifications of lipids, proteins and nucleic acids. This review focuses on the different pathways leading to Reactive Oxygen Species (ROS) production in particular on NADPH oxidase activation. This enzyme is localized in numerous cells including phagocytes and vascular cells and composed of membrane and cytosolic sub-units. The activation of the NADPH oxidase is largely involved in inflammation associated diseases such as asthma, Systemic Inflammatory Response Syndrome and aging associated diseases such as atherosclerosis and neurodeneratives diseases. The modulation of NADPH oxidase could be a way to limit or prevent the development of these diseases.

[Local exercise and oxidative stress in chronic obstructive broncho-pneumopathies: preliminary results]

The role of altered peripheral muscle function in exercise intolerance of chronic obstructive pulmonary disease (COPD) is now well established. However, the mechanisms underlying this phenomen, have not been determined. One hypothesis is that the oxidative stress, that leads to tissue injury may be involved. A recent study has shown that general exercise caused systemic oxidative stress in COPD patients. However, the origin of this stress was not absolutely clear: airways, muscle, both, or other? The aim of this study was first to determine with a systemic approach, whether systemic oxidative stress occur in patients who perform local exercise and then with a muscular needle biopsy approach, to confirm the muscular origin of this oxidative stress.

METHODS

In each approach, 7 COPD patients moderate to severe and 7 age-matched subjects performed an endurance test consisting of dynamic strength of the quadriceps against 40% (systemic approach) or 30% (biopsy approach) of maximal voluntary strength at an imposed regular pace until exhaustion.

RESULTS

The results showed in each approach, that endurance test duration was significantly decreased in the COPD patients (p < 0.05). In systemic approach, the results showed that blood vitamin E at rest was significantly decreased in the COPD (p < 0.001), with a significant increase in superoxide anion release by stimulated phagocytes (p < 0.001). Local exercise induced, only in COPD, a significant increase in serum MDA (p < 0.05), which is an index of oxidative stress. In the biopsy approach, the results showed that local exercise induced in COPD an increase in muscular levels of MDA. A significant increase in muscular peroxidase glutathion activity (antioxidant) occurred after exercise only in normal subjects (p < 0.05). In conclusion, this study in COPD, confirms the altered peripheral muscle function, reveals a deficit in blood vitamin E and suggest that local muscular exercise causes a muscular oxidative stress in these patients. Further studies are needed to confirm these results and evaluate the implication of this oxidative stress in the myopathy of COPD.

[Oxidative stress, hemo-incompatibility and complications of long-term dialysis]

Oxidative stress which results from an imbalance between oxidant production and antioxidant defense mechanisms is now a well recognized pathogenesis factor that could be implicated in the hemodialysis (HD)-related pathology. This review focuses on: 1) factors that may be responsible for oxidative stress in HD patients (hemoincompatibility of the dialysis system--hemoreactivity of the membrane and trace amounts of endotoxins- and uremia per se); 2) implication of such phenomenon in long term complications including anemia, amyloidosis, accelerated atherosclerosis and malnutrition and finally and 3) prevention ways consisting in improving the hemocompatibility of the dialysis system and supplementing the deficiency patients with antioxidants.

Wine phenolic antioxidants inhibit AP-1 transcriptional activity

Some of the beneficial effects of moderate wine consumption may be related to the antioxidant properties of polyphenolic compounds containing tannins, flavonoids, and phenolic acids. Cellular actions have recently been reported and may involve the modulation of transcriptional factors such as AP-1 (activator protein-1), which controls the expression of various genes implicated in inflammation processes, cell differentiation, and proliferation. The aim of this study was to evaluate the modulation of AP-1 activity by the phenolic acids (gallic, caffeic, protocatechic, paracoumaric, sinapic, and ferulic acids) that are present in wine and to compare their modulating pathways to those of lipophilic or hydrophilic "chain-breaking" antioxidants (such as DL-alpha-tocopherol or trolox) vitamin C, nitric oxide, and reduced glutathione. AP-1 response was studied on a cell line (MTLN) derived from MCF-7 cells transfected with luciferase gene under TRE sequence control. After stimulation by phorbol 12-myristate 13-acetate (PMA; 100 nM, 6 h, 10(-7) M), luciferase activity was determined by a luminescence method in the presence of luciferine/coenzyme A solution using a luminometer (LKB 1251, Finland). Antioxidants to be tested were incubated with cells in the presence or absence of PMA. Stimulation with PMA resulted in an AP-1-mediated increase in luciferase gene expression corresponding to an 8-fold increase in luciferase activity. After stimulation by PMA, a dose-dependent inhibition of AP-1 was observed with the six phenolic acids in the 20 nM-20 microM concentration range: gallic acid > caffeic > protocatechic, paracoumaric, sinapic acids > ferulic acid. Inhibition was more pronounced with phenolic acids than with DL-alpha-tocopherol (IC(50) = 5 +/- 4.5 microM for gallic acid vs 85 +/- 11 microM for vitamin E). None of the hydrophilic antioxidants inhibited PMA-induced AP-1 activation. None of the antioxidants tested in the absence of PMA stimulation induced any activation or inhibition of AP-1. Our results suggest that phenolic acids may act directly on cell signaling via inhibition of AP-1 transcriptional activity. In addition to preventing LDL oxidation in the arterial wall, our observations indicate that phenolic acids have a cell-mediated capacity to prevent some of the processes involved in atherosclerosis in a plasma concentration range compatible with nutritional intakes.

[Simvastatin attenuates cardiovascular effects and oxidative stress induced by angiotensin II]

The effects of an HMG-CoA reductase inhibitor, simvastatin (statin, 60 mg/Kg/24 h by forced feeding), were studied on the development of hypertension, cardiac hypertrophy and oxidating stress induced by chronic perfusion of angiotensin II (ANG II, 200 ng/Kg/min s.c., for 10 days) in the rat. The statin was giver 24 hours before, and during the 10 days of ANG II. At the end of the study, mean blood pressure was measured and blood sampling performed under anaesthesia (sodium pentobarbital). The cardiac mass index was measured (cardiac mass/body weight, mg/Kg). TBARS (thiobarbituric acid reactive substances), representing the index of lipid peroxidation, was assessed by fluorimetry. The statin attenuated the development of hypertension (131 +/- 9 vs 164 +/- 4 mmHg) and the increase in cardiac mass (3.13 +/- 0.09 vs 3.46 +/- 0.09 mg/g) associated with ANG II. The overproduction of TBARS induced by ANG II was partially prevented by simvastatin (598 +/- 40 vs 794 +/- 79 pmol/mL). These results indicate that simvastatin attenuates the cardiovascular effects and lipid peroxidation induced by chronic administration of angiotensin II.

Rationale for antioxidant supplementation in hemodialysis patients

Oxidative stress, which results from an imbalance between reactive oxygen species (ROS) production and antioxidant defense mechanisms, is now a well recognized pathogenic process in hemodialysis (HD) patients that could be involved in dialysis-related pathologies such as accelerated atherosclerosis, amyloidosis and anemia. This review is aimed at evaluating the rationale for preventive intervention against oxidative damage during HD as well as the putative causal factors implicated in this imbalance. The antioxidant system is severely impaired in uremic patients and impairment increases with the degree of renal failure. HD further worsens this condition mainly by losses of hydrophilic unbound small molecular weight substances such as vitamin C, trace elements and enzyme regulatory compounds. Moreover, inflammatory state due to the hemo-incompatibility of the dialysis system plays a critical role in the production of oxidants contributing further to aggravate the pro-oxidant status of uremic patients. Prevention of ROS overproduction can be achieved by improvement of dialysis biocompatibility, a main component of adequate dialysis, and further complimented by antioxidant supplementation. This could be achieved either orally or via the extracorporeal circuit. Antioxidants such as vitamin E could be bound on dialyzer membranes. Alternatively, hemolipodialysis consisting of loading HD patients with vitamin C or E via an ancillary circuit made of vitamin E-rich liposomes may be used.

The relationship between apolipoprotein E4 and lipid metabolism is impaired in Alzheimer's disease

BACKGROUND

Human apolipoprotein (Apo) E4 (ApoE4) is an important determinant of lipid metabolism and cell-to-cell cholesterol transport. It is also a major genetic risk factor for both vascular disease and familial and sporadic late-onset Alzheimer's disease (AD). Since vascular pathology could dramatically reduce neuronal reserve capacity, a biological chain of events between ApoE4, hypercholesterolemia and AD has been postulated. The aim of the present study is to explore the relationship between lipid metabolism and ApoE isoforms in a large series of elderly subjects in relation to the presence or absence of AD.

METHODS

Of 332 referrals to a neurology clinic specializing in memory disorders, 146 were given a diagnosis of AD (age, mean +/- SD 76 +/- 13.1 years, 64.4% women) according to DSM-IIIR criteria. One hundred and seventy-six subjects were included as controls (age 80 +/- 5.6 years, 58% women). The ApoE phenotype was determined by the isoelectrofocalization method, cholesterol, triglycerides, phospholipids, ApoA and ApoB were determined by routine chemistry.

FINDINGS

A significant association was observed between the E4 allele and AD (chi2 = 13, p < 0.001) only below age 80. In the control group, cholesterol levels were found to be significantly higher in men but not in women with an E4 allele (6.35 +/- 1.3 mmol/l) as opposed to those without (5.8 +/- 1.2 mmol/l). ApoB levels were also found to be higher in the presence of ApoE4, with no gender effect. Within the AD group no significant relationship was found between ApoE4 and cholesterol levels (mean 6.05 +/- 0.9 mmol/l in E4-AD subjects versus 5.8 +/- 1.21 mmol/l in non-E4-AD subjects). Similar observations were made in relation to triglycerides and phospholipids.

INTERPRETATION

Our results demonstrate the disappearance of the ApoE4-raising effect on serum cholesterol, triglyceride and phospholipid levels in AD suggesting a more complex relationship between AD and lipid metabolism than has previously been supposed. This lipid abnormality may further contribute to the progression of AD.

Discrepancies between apolipoprotein E phenotyping and genotyping in the elderly

We estimated the frequencies of phenotype (isoelectric focusing; IEF) vs. genotype (PCR/Hhal) discordance in a sample of an aged population (> 65 years). Both phenotype and genotype techniques have been used in the study of apolipoprotein E (apoE) polymorphism in 125 elderly subjects. The discordance between phenotype and genotype was unresolved in 11 (8.8%) of the 125 unrelated subjects studied. We observed a significant association between the presence of the E4 allele and both Alzheimer's disease (chi2 = 13, p < 0.001) and increased cholesterol concentration (Mann Whitney, p < 0.03). These relationships were not affected by the techniques used. Our results indicate that transcriptional modulation and post-transductional modifications in normal ageing and in aged-related diseases may explain in part discrepancies between gene analysis and protein characterisation.

Antilymphocyte globulins versus OKT3 as prophylactic treatment in highly sensitized renal transplant recipients

Monoclonal antibodies were proposed as an effective prophylactic immunosuppressive treatment in highly sensitized patients (HSP). In this study we compared the results obtained in HSP treated with OKT3 or antilymphocyte globulins (ALG). From January 1989 to January 1993, 38 transplantations were performed in patients with high panel reactive antibodies (PRA > 50%). The group comprised 22 women and 16 men, mean age 45 +/- 2 (23-67) years; ten were second grafts and two were third grafts. Peak PRA was > or = 80% in 24 sensitized patients and 50-80% in 14 sensitized patients. Patients were randomly assigned to either prophylactic OKT3 (n = 15) or ALG (n = 23). Oral cyclosporin A (10 mg/kg) was started at day 8 in the OKT3 group and when the serum creatinine level decreased to 200 micromol/l in the ALG group. OKT3 was systematically withdrawn on day 10 but ALG was stopped only when total blood cyclosporin A concentration reached 150-200 ng/ml. In both groups, azathioprine (150 mg/day) and prednisolone were given. During the first months, 6/15 grafts were lost in the OKT3 group (three hyperacute rejections, one renal vein thrombosis, one steroid-resistant rejection, one death); in the ALG group 4/23 grafts were lost (one hyperacute rejection, two steroid-resistant rejections, one death). Side effects were significantly more frequent in the OKT3 group than in the ALG group. After 12 months of follow up, the graft survival was 71% (27/38) and did not significantly differ (log-rank test, NS) between the OKT3 (60%, 9/15) and the ALG group (78%, 18/23). We conclude that the use of the monoclonal antibody OKT3 as a prophylactic agent in HSP does not improve the early graft survival when compared with prophylactic ALG. Polyclonal antibodies, which react with many epitopes and are much better tolerated seem to offer a good strategy for induction therapy in this population.

Why hemodialysis patients are in a prooxidant state? What could be done to correct the pro/antioxidant imbalance

Oxidative stress which results from an imbalance between reactive oxygen species production and antioxidant defense mechanisms is now well recognized in hemodialysis (HD) patients and could be involved in dialysis-related pathologies such as accelerated atherosclerosis, amyloidosis and anemia. In order to evaluate the rationale for preventive intervention against oxidative damage during HD, we review the factors that are implied and may be responsible for the imbalance between pro- and antioxidative mechanisms. The inflammatory state mainly due to hemobioincompatibility of the dialysis system plays a critical role in the production of free oxygen radical species contributing by this way to worsen the prooxidant status of uremic patients. Two factors largely contribute to the stimulation of the NADPH oxidase: hemoreactivity of the membrane and trace amounts of endotoxins. The antioxidant system is severely impaired in uremic patients and gradually altered with the degree of renal failure. HD could further impair this antioxidant system mainly by losses of (a) hydrophilic unbound small-molecular-weight substances such as vitamin C, (b) trace elements and (c) enzyme-regulatory compounds. Two main axes may be proposed in order to prevent and/or to decrease oxidative stress in HD patients. One consists in improving the hemocompatibility of the dialysis system mainly by using a dialyzer with low hemoreactivity and ultrapure, sterile, nonpyrogenic dialysate. The other consists in supplementing the deficiency patients with antioxidants. This could be achieved by oral or perdialytic supplementation. Vitamin E could be bound on dialyzer membrane. Alternatively, hemolipodialysis consists in loading HD patients with vitamin C or E via an ancillary circuit made of vitamin E-rich liposomes. The presence of liposomes could also facilitate the removal of hydrophobic prooxidative substances.

Serum fatty acid imbalance in bone loss: example with periodontal disease

Among the numerous factors of bone remodelling, the local action of arachidonic acid metabolites together with cytokines, is particularly important, especially that of prostaglandin PGE2. It has been suggested that the alveolar bone destruction in periodontal disease and osteoporosis can be treated by reducing the ratio of arachidonic acid in phospholipids, which would diminish prostaglandin production. The aim of this study was to evaluate the main serum polyunsaturated fatty acids and a possible alteration in the level of arachidonic acid in patients suffering from periodontal bone loss. Of the 105 patients who participated the study, 78 were suffering from periodontal bone loss and 27 served as a control group. The fatty acids were measured in serum by gas-chromatography. The results showed that the level of fatty acids of the n-6 pathway was higher in our patients with bone loss than in the control group, whereas the reverse was observed with fatty acids of the n-3 pathway. In conclusion, our patients' bone losses are linked with an imbalance between n-6 and n-3 fatty acids, which seems to justify a diet increase in 20- and 22-carbon fatty acids.

Cholesterol biosynthesis in normocholesterolemic patients after cholesterol removal by plasmapheresis

Plasmapheresis and low-density lipoprotein (LDL)-apheresis are recognized procedures for the treatment of hyperlipidemia resistant to diet and lipid-lowering drugs and provide information on cholesterol synthesis in hypercholesterolemic patients. However, cholesterol synthesis after acute cholesterol removal from plasma has never been investigated in normocholesterolemic patients. In this study, cholesterol synthesis was evaluated in three normocholesterolemic patients by determination of plasma lathosterol, lathosterol-to-cholesterol ratio, and plasma mevalonic acid. In a short-term kinetic study, samples were collected before and after plasmapheresis and every 6 hours during 24 hours. In the second part of the study, cholesterol synthesis was evaluated daily for 3 days. In normocholesterolemic patients, cholesterol returns to basal levels in 3 days. However, cholesterol removal did not result in a significant increase in lathosterol-to-cholesterol ratio or in plasma mevalonic acid, despite a slight increase in lathosterol. In contrast, when repeated plasma exchanges induced a dramatic hypocholesterolemia (< 1 mmol/liter), an acute but transient stimulation of cholesterol synthesis was observed (lathosterol/cholesterol ratio and MVA, respectively, increase from 8.2 to 22.3 and from 28 nmol/liter to 98 nmol/liter). This study shows that cholesterol synthesis is not stimulated by plasmapheresis in normocholesterolemic patients but is enhanced in dramatic hypocholesterolemic patients (< 1 mmol/liter).

Protective effects of high-density lipoprotein against oxidative stress are impaired in haemodialysis patients

INTRODUCTION

Cardiovascular diseases represent the major cause of mortality in haemodialysis (HD) patients. Oxidized low-density lipoprotein (Ox-LDL) is a major cardiovascular risk factor, implicated in atherosclerotic plaque formation. It has been suggested that high-density lipoprotein (HD) has the capacity to reduce the oxidative modifications of LDL. The aim of this study is to analyse the protective effects of HDL in HD patients.

METHODS

In vitro copper-induced LDL oxidation was evaluated in 12 patients with chronic renal failure (mean age 61.0+/-12.8 years) and compared to 25 healthy subjects (mean age 57.3+/-19.2 years). LDL were incubated in oxygen-saturated PBS, LDL oxidation was initiated by Cu (II) in the presence and absence of HDL and assessed by measuring the absorbance (abs) increase at 234 nm due to conjugated diene formation. Duration of lag time, maximum velocity (V(max.)) of lipid peroxidation, oxidation slope and half-time of maximum diene formation (T (1/2)) were obtained by kinetic modelling analysis.

RESULTS

HDL (1.06+/-0.31 vs 1.23+/-0.39 mmol/l) and Apo AI (1. 17+/-0.39 vs 1.49+/-0.20 g/l) levels were decreased in HD patients. In the absence of HDL, LDL obtained from HD patients showed an enhanced susceptibility to oxidation in vitro as demonstrated by the significant decrease in lag time (54.5+/-22.2 vs 79.4+/-37.8 min) and a significant increase in V(max.) (0.026+/-0.006 vs 0.017+/-0. 005 abs/min). In all cases, HDL (from 0.1 to 2 microM) prevented LDL oxidation in vitro; however, this effect was significantly reduced in HD patients: increase in lag time 54.2% vs 150.4% in HD vs controls; increase in T (1/2) 52.2% vs 124.6% in HD vs controls; decrease in V(max). 13.5% vs 38.5% in HD vs controls.

CONCLUSIONS

These results suggest that qualitative abnormalities such as an impairment of HDL-associated enzymes are associated with a decrease of HDL levels during HD. Hence, in addition to the known impairment of reverse cholesterol transport, the reduction of HDL protective capacity against oxidative stress could be involved in the development of HD-induced atherosclerosis.

Risk factors for cortical, nuclear, and posterior subcapsular cataracts: the POLA study. Pathologies Oculaires Liées à l'Age

The POLA (Pathologies Oculaires Liées à L'Age) Study is a population-based study of cataract and age-related macular degeneration and their risk factors being carried out among 2,584 residents of Sète, southern France, aged 60-95 years. Recruitment took place between June 1995 and July 1997. Cataract classification was based on a standardized lens examination by slit lamp, according to Lens Opacities Classification System III. This paper presents results obtained from cross-sectional analysis of the first phase of the study. In polytomous logistic regression analyses, an increased risk of cataract was found for female sex (cataract surgery: odds ratio (OR) = 3.03; cortical cataract: OR = 1.67), brown irises (cortical, nuclear, and mixed cataracts: OR = 1.61), smoking (cataract surgery: OR = 2.34 for current smokers and OR = 3.75 for former smokers), known diabetes of 10 or more years' duration (posterior subcapsular, cortical, and mixed cataracts and cataract surgery: OR = 2.72), use of oral corticosteroids for at least 5 years (posterior subcapsular cataract: OR = 3.25), asthma or chronic bronchitis (cataract surgery: OR = 2.04), cancer (posterior subcapsular cataract: OR = 1.92), and cardiovascular disease (cortical cataract: OR = 1.96). Decreased risk of cataract was found with higher education (all types of cataract and cataract surgery: OR = 0.59), hypertension (cataract surgery: OR = 0.57), and high plasma retinol levels (nuclear and mixed cataracts and cataract surgery: OR = 0.75 for a 1-standard-deviation increase). Most of the risk factors identified in this study confirm the findings of other studies. The association of cataract with plasma retinol level requires further investigation.

Tau and apo E in CSF: potential aid for discriminating Alzheimer's disease from other dementias

To evaluate the usefulness of tau proteins as biological markers in the diagnosis of dementia of the Alzheimer type (DAT), we analyzed the concentration of tau proteins in 253 cerebrospinal fluid (CSF) samples from patients with or without neurological disorders. Our study showed a significant increase of the mean CSF tau concentration in DAT patients compared with that from non-DAT patients. Interestingly, a significative decrease of CSF tau in patients with frontotemporal dementia was found. We also observed a positive correlation between the CSF-tau concentration and the number of apoepsilon4 alleles. The CSF apolipoprotein E concentration was evaluated and revealed no variation between the groups, although we observed a significant correlation between CSF tau and apolipoprotein E in DAT patients.

Age-related macular degeneration and antioxidant status in the POLA study. POLA Study Group. Pathologies Oculaires Liées à l'Age

OBJECTIVE

To give the levels of antioxidant nutrients in relation to age-related macular degeneration (AMD).

METHODS

Pathologies Oculaires Liees a l'Age is a population-based study on cataract and AMD and their risk factors, carried out on 2584 inhabitants of Sete, France. Age-related macular degeneration was defined by findings from fundus photographs according to an international classification. Biological measurements were taken from fasting blood samples.

RESULTS

After multivariate adjustment, plasma alpha-to-copherol levels showed a weak negative association with late AMD (P = .07). Lipid-standardized plasma alpha-tocopherol levels showed a significant negative association with late AMD (P= .003): the risk of late AMD was reduced by 82% in the highest quintile compared with the lowest. Similarly, lipid-standardized plasma alpha-tocopherol levels were inversely associated with early signs of AMD (odds ratio, 0.72 [95% confidence interval, 0.53-0.98]; P=.04). No associations were found with plasma retinol and ascorbic acid levels or with red blood cell glutathione values.

COMMENT

These results suggest that vitamin E may provide protection against AMD. Only randomized interventional studies could prove the protective effect of vitamin E on AMD.

[Kinetic modeling of LDL oxidation using software (NELOP program) and validation in a population at vascular risk]

Oxidized LDL (low density lipoprotein) are considered to be the major initiating event in atherogenesis. In vitro models have been studied but no mathematic modeling can assess quantitatively the oxidability of LDL and antioxidant effects. We have developed a mathematic modeling allowing quantification of different kinetic parameters to LDL oxidation. This model has been validated by means of a software (software NELOP) in normal population (HV) and in a cardiovascular risk population, hemodialysis (HD). LDL are collected and purified by sequential ultracentrifugations from 12 healthy volunteers and hemodialysis patients. LDL oxidability (0.1 microM) is initiated by 5 microM copper and monitored continuously by conjugated diene production. All parameters are evaluated and correlated to those obtained by NELOP. Significant correlations between measured and calculated parameters (Vmax: r2 = 0.99, p < 0.05) allow to validate NELOP in both populations. Our results show that hemodialysis LDL present an enhanced susceptibility to copper induced oxidation (lag time: 96.6 +/- 48.6 mn in HV versus 54.5 +/- 22.2 mn in HD). NELOP seems to be a useful tool to evaluate LDL oxidation in cardiovascular risk populations.

Differences between polyunsaturated fatty acid status of non-institutionalised elderly women and younger controls: a bioconversion defect can be suspected

OBJECTIVE

To evaluate the polyunsaturated fatty acid (PUFA) status in non-institutionalised elderly women and to detect a possible essential fatty acid bioconversion defect.

DESIGN AND SUBJECTS

The fatty acid composition of total plasma lipids, plasma triglycerides (TG), cholesterol esters (CE), phospholipids (PL), and erythrocytes was determined by capillary column gas-liquid chromatography in a sample of 200 non-institutionalised healthy elderly women over 75 years of age. The data were compared with those of a control group of 50 young female volunteers aged 20-48 y.

RESULTS

In elderly women, the n-6 series precursor, linoleic acid (18:2 n-6), was lower in TG and CE (P = 0.029 and 0.014, respectively). In CE, this fatty acid was highly correlated with vegetable and vegetal fat intakes (P < 0.0001), suggesting a lower dietary supply than in controls. Higher percentages of 16:1 n-7 were found in all the plasma lipid fractions in elderly women, especially in CE (P < 0.0001). The ratios 20:4 n-6/20:3 n-6 and 22:6 n-3/20:5 n-3 were significantly lower in PL from elderly women (P < 0.005 and P < 0.002, respectively), raising the question of the efficiency of the terminal steps of 20:4 n-6 and 22:6 n-3 biosynthesis. Dietary investigations in elderly women indicated that a high dietary protein intake via meat probably contributed to the supply of 20:4 n-6 and thus maintained the status of this fatty acid, despite the suspected altered biosynthesis.

CONCLUSION

The PUFA status in the elderly women group could be more fragile and dependent on exogenous supply of long-chain PUFAs than previously suspected.