Serum Selenium Status and Its Interrelationship with Serum Biomarkers of Thyroid Function and Antioxidant Defense in Hashimoto's Thyroiditis.

Selenium (Se) deficiency has been implicated in the pathogenesis of Hashimoto's thyroiditis (HT), although the available evidence is limited. The present study aimed to explore the interrelationships between serum Se status with measures of thyroid function and antioxidant defense in new cases of HT patients with hypoechogenic thyroid. HT patients (n = 49) and matched controls (n = 50) were recruited. Selenium, thyroid hormone panel, thyroid volume (TVol), glutathione (GSH), glutathione peroxidase3 (GPx3) activity, urinary iodine concentration (UIC), and urinary creatinine (Cr) were assessed. HT patients exhibited lower Se levels compared to controls (p < 0.001) with the rates of Se-deficient (<0.85 µmol/L) participants being 58.8% and 34%, respectively. Se-deficient patients exhibited higher thyroid stimulating hormone (TSH), Thyroid volume (TVol), thyroglobulin, antibody-titers, GPx3 activity and UIC/Cr compared to Se-sufficient patients (all p < 0.001). In the Se-deficient patients, inverse correlations were seen between Se-levels with TSH, TVol, and Thyroid peroxidase antibody (TPO-Ab) (all p < 0.001). This study is the first to uncover that coexisting Se-deficiency and elevated iodine in HT may enhance autoimmune reactions and accelerate the deterioration of thyroid function through oxidative stress. Our study also highlights the importance of optimal Se status in this disease, thus providing a rationale for the execution of intervention trials for the evaluation of the clinical benefits of antioxidant-status improvement in HT.

Isoprostane in systemic sclerosis: A systematic review and meta-analysis.

OBJECTIVES: To further the knowledge of oxidative stress in systemic sclerosis (SSc), we performed a systematic review and meta-analysis on studies measuring isoprostane, a vasoactive agent deriving from arachidonic acid and implicated in the vasculopathy of SSc. METHODS: Systematic search following the PRISMA guidelines in PubMed and EMBASE between January-1990/December-2017 using the terms: oxidative stress, isoprostane, systemic sclerosis and scleroderma. RESULTS: After the screening process, 8 studies including 240 SSc patients and 192 controls were included in the systematic review and meta-analysis, 6 investigating urinary and 2 serum isoprostane: random effect meta-analysis revealed isoprostane overgeneration in SSc (p < .001) with wide heterogeneity (I2 = 75%). Subgroup analysis on urinary isoprostane favoured excess excretion in SSc (p = .009) with slightly lower heterogeneity (I2 = 67%); further subgroup analysis according to unit of measurement revealed no increased isoprostane excretion when expressed as pg/mg creatinine but increased when expressed as pmol/mmol creatinine (p = .05) with medium heterogeneity (I2 = 32%). Subgroup analysis on serum isoprostane favoured overproduction in SSc (p < .0001) with no heterogeneity. CONCLUSION: There is some evidence for isoprostane overgeneration in SSc that confirms the occurrence of oxidative stress in this setting: further prospective studies with specified outcomes are needed to evaluate the prognostic value of this functional biomarker.

Lipopolysaccharide-Induced VEGF Production and Ambient Oxidative Stress in Type 2 Diabetes.

Context: Oxidative stress is implicated in the development of vascular disease and is associated with an upregulation of vascular endothelial growth factor (VEGF), which is pathogenetically linked to the microvascular complications of diabetes. Patients of African origin have an increased susceptibility to microvascular kidney disease compared with white patients; the reasons and mechanisms that contribute to this vulnerability are unclear. Objectives: To investigate whether there are ethnic differences in lipopolysaccharide-induced monocyte VEGF production in whole blood cell cultures. In addition, to assess whether stimulated VEGF production is related to prevailing oxidative stress assessed by plasma lipid hydroperoxides (LOOHs) and α-tocopherol. Design and Setting: Cross-sectional study at a secondary care center in North London, United Kingdom, serving an inner-city community of 154,000 adults. Patients: African-Caribbean and white patients with type 2 diabetes mellitus [(T2DM); n = 52]. Results: Lipopolysaccharide-induced production of VEGF in whole blood cultures [61.8 (31.9) pg/mL to 78.4 (6.0) pg/mL; P < 0.001] correlated positively with LOOH levels (r = 0.3, P = 0.04) and was significantly higher in African-Caribbean than white patients with T2DM [404 (207.5) vs 268.8 (137.0)] pg/mL ×109/L monocytes; P = 0.018]. Plasma α-tocopherol concentration was higher in Caucasian (white) patients [40.3 (18.3) vs 30.0 (9.6)] µmol/L; P = 0.04] compared with African-Caribbean patients. Conclusions: This study suggests that the redox environment influences VEGF production in response to proinflammatory stimuli in T2DM. The differential responsiveness by ethnic origin may be of relevance in the variations in susceptibility to the long-term microvascular complications.

Oxidative/nitrative stress in the pathogenesis of systemic sclerosis: are antioxidants beneficial?

Systemic sclerosis (SSc) is a multisystem autoimmune disease: characterised from the clinical side by progressive vasculopathy and fibrosis of the skin and different organs and from the biochemical side by fibroblast deregulation with excessive production of collagen and increased expression of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4). The latter contributes to an overproduction of reactive oxygen species that through an autocrine loop maintains NOX4 in a state of activation. Reactive oxygen and nitrogen species are implicated in the origin and perpetuation of several clinical manifestations of SSc having vascular damage in common; attempts to dampen oxidative and nitrative stress through different agents with antioxidant properties have not translated into a sustained clinical benefit. Objective of this narrative review is to describe the origin and clinical implications of oxidative and nitrative stress in SSc, with particular focus on the central role of NOX4 and its interactions, to re-evaluate the antioxidant approaches so far used to limit disease progression, to appraise the complexity of antioxidant treatment and to touch on novel pathways elements of which may represent specific treatment targets in the not so distant future.

Oxidative stress predicts progression of peripheral and cardiac autonomic nerve dysfunction over 6 years in diabetic patients.

Oxidative stress is implicated in the pathogenesis of experimental diabetic neuropathy, but prospective studies in diabetic patients are lacking. We aimed to evaluate whether the plasma levels of various biomarkers of oxidative stress predict the progression of diabetic neuropathy and mortality over 6 years. We followed 89 diabetic patients aged 54 ± 14 years (59 % with polyneuropathy), 72 of whom underwent nerve function reassessment after 6.2 ± 0.8 years, whereas 17 died after 4.2 ± 1.0 years. Plasma markers of oxidative stress at baseline included superoxide anion, hypochlorous acid, peroxynitrite, 8-iso-prostaglandin F2α, vitamin E/lipid ratio, and vitamin C. Neuropathy was assessed by symptoms and deficits, motor and sensory nerve conduction velocity (MNCV, SNCV), vibration perception thresholds (VPT), thermal detection thresholds, and heart rate variability (HRV). Despite a reduction in HbA1c by 1.4 ± 1.6 % (p < 0.001), median SNCV, sural SNCV, peroneal MNCV, malleolar VPT, and warm TDT deteriorated after 6 years (all p < 0.05). In multivariate models, increased superoxide generation was associated with a decline in median SNCV (ß = -0.997; p = 0.036) and deterioration in HRV at rest (OR 1.63 [95 % CI 1.09-2.44]; p = 0.017) over 6 years. Low vitamin E/lipid ratio tended to predict a decrease in peroneal MNCV (ß = 0.781; p = 0.057) and an increase in malleolar VPT (ß = -0.725; p = 0.077). Plasma superoxide generation was associated with an increased risk of mortality (HR 23.2 [95 % CI 1.05-513]; p = 0.047). In conclusion, increased plasma superoxide generation predicted the decline in sensory and cardiac autonomic nerve function and mortality over 6 years in diabetic patients, but larger studies are required for confirmation.

Plasma glutathione peroxidase activity in kidney recipients with and without adverse outcome.

Kidney function is routinely monitored utilizing classic biochemical parameters including serum or plasma creatinine (Cr), and blood urea nitrogen (BUN) concentrations. This study demonstrates that the simultaneous assessment of plasma glutathione peroxidase (pGPx) and Cr levels provides a better strategy for the immediate follow-up of kidney function in organ recipients. Kidney recipients (Krs; n = 22) were recruited. Blood sampling schedule commenced at day 1 (pre-transplantation) and post-transplantation days (i.e., everyday from 1 until day 14, and thereafter on days 21, 28, 35, 42, 49, and 56). pGPx was measured spectrophotometrically. Candidates for transplantation exhibited lower pGPx than control subjects (42 ± 24 vs. 143 ± 31 U/L; p < 0.005). In Krs with a stable post-transplant outcome, pGPx increased to a maximum at day 28 (214 ± 61 U/L). In a Kr diagnosed with acute tubulonecrosis, pGPx provided a better predictive value (threefold increase) than Cr. In a Kr diagnosed with acute rejection, the increment in Cr values was found to be more pronounced than in pGPx values. The pGPx test is simple, inexpensive and automatable, and should be a valuable diagnostic tool of kidney function in organ recipients with and without troublesome outcome for the follow-up during hospitalization period.

Nutritional iodine status in gestation and its relation to geographic features in Urmia County of northwest Iran.

BACKGROUND: Iodine is an important component for the proper function of the thyroid and fetal development. OBJECTIVE: To evaluate the influence of geographic variation on nutritional iodine status during pregnancy. METHODS: Four hundred eighty-nine women in the first trimester of pregnancy were enrolled. Of these, 419 (85.5%) were from the plain districts and 70 (14.5%) from mountainous regions. Data were obtained on demographic characteristics and accessibility of iodized salt, and samples of table salt were collected. In the third trimester, 322 women remained in the study: 281 (87.2%) from the plains and 41 (12.8%) from the mountainous regions. Salt and urine samples were analyzed for iodine content. RESULTS: All participants stated that they used iodized table salt. The proportion of salt samples with optimal iodine content (30 ppm) from the plains and mountain regions were 68.7% and 88%, respectively. The median urinary iodine content (UIC) in the plains area in the first and third trimesters was 82 and 119 microg/L, respectively. The corresponding values in the mountain region were 34.5 microg/L and 76 microg/L. The prevalence of subjects with an inadequate iodine intake (UIC < 150 microg/L) in first and third trimester in the plains and mountain regions were 84.5% and 66.9% vs 98.6% and 90.2%, respectively. CONCLUSIONS: The prevalence of pregnant women exhibiting UIC < 150 microg/L in the mountain region was substantially higher than those in the plain district. Our findings also show that the current strategy for eradication of iodine deficiency in school-aged children would not fulfill iodine requirements in pregnancy and that additional source(s) of iodine are required to prevent the adverse effects of iodine deficiency in pregnancy. Further studies are needed to address the cause(s) for the rapid depletion of iodine stores in pregnancy.

Key issues in F2-isoprostane analysis.

A large body of evidence indicates that measurement of F2-isoprostanes, specific prostaglandin F2-like compounds derived from the non-enzymatic peroxidation of arachidonic acid, is a reliable biomarker of oxidant stress in the human body. Since the discovery of F2-isoprostanes in the early 1990s, a variety of analytical approaches has been introduced for the quantification of these novel compounds. The aim of the present review is to shed light on the available gas chromatographic-mass spectrometric assays for the measurement of plasma or urinary F2-isoprostanes and to highlight a number of issues which need to be addressed in order to implement F2-isoprostane measurement as a gold-standard biomarker of oxidative stress in biological samples.

Impact of diabetic polyneuropathy and cardiovascular autonomic neuropathy on the excretion of urinary 8-epi-PGF2alpha and its metabolites (2, 3-dinor and 2, 3-dinor-5, 6-dihydro).

The objective of this study was to establish if diabetes in the presence of polyneuropathy (PN) and/or cardiovascular autonomic neuropathy (CAN) is associated with alterations in the amounts of 8-epi-PGF2alpha (IP) and its metabolites including 2, 3-dinor-8-epi-PGF2alpha (dinor-IP) and 2, 3-dinor-5, 6 dihydro-8-epi-PGF2alpha (dinor-dihydro-IP) in urine. Mass spectrometric separation showed that excretion of IP was similar in the PN + /CAN- and PN+/CAN+ groups but higher than in the PN-/CAN- group (n = 103, 22 and 60, respectively; P < 0.05). By contrast, excretion of dinor-IP or dinor-dihydro-IP were similar in the PN-/CAN- and PN+/CAN- groups but higher than in PN+/CAN+ group. Correlations were obtained between IP and dinor-IP or dinor-dihydro-IP (r = 0.30; P < 0.001 and r = 0.31; P < 0.001, respectively). A significant association was also observed between dinor-IP and dinor-dihydro-IP (r = 0.48; P < 0.001). In conclusion, these biomarkers should prove useful in studies evaluating the impact of therapeutic drugs or antioxidant interventions aimed at delaying the onset of diabetic complications.

The use of pholasin as a probe for the determination of plasma total antioxidant capacity.

BACKGROUND AND OBJECTIVES: Total antioxidant capacity (TAC) reflects the capacity of plasma, or other body fluid, to resist oxidation. The aim of the present study was to assess the prognostic value of Pholasin as a probe for the determination of plasma TAC. DESIGN AND METHODS: Plasma samples either oxidised using the free radical generator 2'-azobis-(2-amidinopropane) hydrochloride (AAPH) at 60 degrees C for 180 min or obtained from diabetic (type 1 and type 2) patients (n = 61 and 124, respectively) with or without polyneuropathy (PN) and/or cardiovascular autonomic neuropathy (CAN) and control subjects (n = 70) were analysed for TAC status. TAC was assessed using two versions of Analysis By Emitted Light (ABEL) tests including quenching of Pholasin chemiluminescence (QPC) with peroxynitrite (ONOO(-)-QPC) and with superoxide anion (O2(-)-QPC). RESULTS: The utilisation of AAPH to induce peroxyl radical mediated plasma oxidation produced a significant decrease in TAC as assessed by ONOO(-)-QPC and O2(-)-QPC assays in a time-dependent manner. Type 1 and type 2 diabetic patients without PN and/or CAN had lower TAC (ONOO(-)-QPC and O2(-)-QPC) than in control subjects. Further alterations in TAC were noted in the presence of PN and/or CAN. Correlations were found between TAC (ONOO(-)-QPC and O2(-)-QPC) values on duration of diabetes and neurological impairment score-lower limb (NIS-LL) in type 1 diabetic patients. CONCLUSIONS: This study has established that the ONOO(-)-QPC and O2(-)-QPC versions of the ABEL test fulfil the criteria in terms of simplicity, sensitivity and reliability for the measurement of plasma TAC. These biomarkers may prove useful in studies evaluating the impact of therapeutic drugs or antioxidant interventions aimed at delaying the onset of complications in clinical conditions associated with oxidative stress.

Race-specific differences in antioxidant enzyme activity in patients with type 2 diabetes: a potential association with the risk of developing nephropathy.

OBJECTIVE: Lipid hydroperoxide, a marker of oxidative stress, is linked to the development of nephropathy and is reportedly higher in patients of African origin compared with Caucasians. This may be relevant to race-specific differences in susceptibility to nephropathy. We investigated whether alterations in antioxidant enzyme activity could account for this biochemical phenotype and examined the relationship with conventional markers of renal disease. RESEARCH DESIGN AND METHODS: Two hundred seventeen individuals were studied. Patients with type 2 diabetes (n = 75) of African and Caucasian origin were matched by sex and racial origin with healthy control subjects (n = 142). Plasma total superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity were spectrophotometrically measured, and total cholesterol and triglycerides were measured by enzymatic methods. RESULTS: SOD activity was higher and GPx activity lower in patients with diabetes than in healthy control subjects (573 +/- 515 vs. 267 +/- 70 units/l, P < 0.001 and 150 +/- 93 vs. 178 +/- 90 units/l, P = 0.019, respectively). Patients of African origin with diabetes had lower GPx and higher SOD activity compared with Caucasian patients (126 +/- 82 vs. 172 +/- 97 units/l, P = 0.03 and 722 +/- 590 vs. 445 +/- 408 units/l, P = 0.002, respectively). Patients of African origin with normal urinary albumin excretion had significantly higher plasma creatinine concentrations (100.7 +/- 14.2 vs. 88.1 +/- 14.9 micromol/l, P = 0.007) and lower GPx activity (99.0 +/- 72.4 vs. 173.7 +/- 107.4 units/l, P = 0.02) compared with those of Caucasian origin. African origin was an independent predictor of elevated SOD (P = 0.007) and reduced GPx activity (P = 0.02) in regression analysis. CONCLUSIONS: SOD and GPx enzyme activities vary according to race and could account for differences in lipid hydroperoxide. In patients of African origin, susceptibility to renal disease may be associated with lowered GPx activity.

Circulating vitamin E, transforming growth factor beta1, and the association with renal disease susceptibility in two racial groups with type 2 diabetes.

BACKGROUND: End-stage renal disease caused by diabetes disproportionately affects patients of African origin. The biological mechanism(s) for this observation is unclear. Emerging data from cross-sectional studies suggest that increased oxidative stress and the cytokine, transforming growth factor beta(1), are associated with this phenomenon. Therefore, a pathway involving these factors could alter the vulnerability to renal disease and impact adversely on the rate of loss of renal function. METHODS: We assessed the relationship between renal function, oxidative stress, and transforming growth factor beta(1) in 58 patients with type 2 diabetes of African and Caucasian origin over 174 patient-years of follow-up. Oxidative stress was assessed by measuring plasma lipid hydroperoxide and vitamin E in the postprandial state. Creatinine clearance was calculated from the Cockcroft-Gault equation. Patients received standardized management of hypertension, hyperglycemia, and hypercholesterolemia. Data were adjusted by multiple regression analysis to account for potential confounders. RESULTS: Lipid hydroperoxide was higher and vitamin E lower, while there was no difference in fasting transforming growth factor beta(1) between the African (N= 22) and Caucasian (N= 36) patients [5.1(1.2) vs. 4.3 (1.8) micromol/L; P= 0.02 and 29.8 (10.8) vs. 41.3(19.7) micromol/L; P= 0.02 and 6.33 (5.5) vs. 6.84 (3.9) ng/mL; P= 0.73], respectively. The mean (95% confidence interval) of the difference in creatinine clearance between the patients of African and Caucasian origin was -12.5 (-23.4 to -1.7) mL/min; P= 0.015 at baseline, the magnitude of which increased to -17.5 (-28.4 to -6.5) mL/min; P= 0.002 after 3 years. The fall in creatinine clearance from baseline among the patients of African origin was greater for lower levels of vitamin E (rho = 0.48; P= 0.03). Final plasma creatinine was significantly higher in the African patients compared with the Caucasian patients [109.0 (25.8) vs. 94.0 (20.0) micromol/L; P= 0.0017]. In regression analysis, vitamin E was a significant and independent predictor of plasma creatinine (t -3.17, P= 0.003). CONCLUSION: In these patients with type 2 diabetes, vitamin E is a determinant of renal function, and may explain some of the racial differences in renal disease susceptibility that precedes the divergence in incidence of end-stage renal disease.

Oxidative stress and antioxidant defense in relation to the severity of diabetic polyneuropathy and cardiovascular autonomic neuropathy.

OBJECTIVE: Oxidative stress resulting from enhanced free-radical formation and/or a defect in antioxidant defenses has been implicated in the pathogenesis of experimental diabetic neuropathy. The objective of this study was to evaluate plasma levels of various biomarkers of oxidative stress in diabetic subjects in relation to the presence or absence of polyneuropathy (PN) and/or cardiovascular autonomic neuropathy (CAN). RESEARCH DESIGN AND METHODS: Plasma 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)), superoxide anion (O(2)(.-)) generation, lag phase to peroxidation by peroxynitrite (ONOO(-)), vitamin E-to-lipid ratio, and vitamin C were measured in nonsmoking diabetic patients without PN and CAN (PN(-)/CAN(-) group; n = 62), in a group with PN but without CAN (PN(+)/CAN(-) group; n = 105), in those with both PN and CAN (PN(+)/CAN(+) group; n = 22), and in healthy control subjects (n = 85). RESULTS: All three markers of oxidative stress were significantly increased, and both markers of antioxidant defense were decreased in the PN(+)/CAN(-) group compared with the control group (all P < 0.05). PN(-)/CAN(-) subjects showed a significant increase compared with control subjects for 8-iso-PGF(2alpha), O(2)(.-), and ONOO(-) and a decrease for the vitamin E-to-lipid ratio (all P < 0.05). In the PN(+)/CAN(-) group, a significant increase compared with the PN(-)/CAN(-) group was noted for O(2)(.-), whereas the vitamin E-to-lipid ratio and vitamin C were reduced (all P < 0.05). No significant differences were noted between the PN(+)/CAN(-) and PN(+)/CAN(+) groups for each of the five markers of oxidative stress. In multivariate models, O(2)(.-) and ONOO(-) were independently associated with neuropathic deficits, but diabetes duration and triglyceride levels were also independent determinants. CONCLUSIONS: Oxidative stress is enhanced in diabetic patients before the development of PN but to an even higher degree in those with PN, without further significant increase in relation to superimposed autonomic neuropathy. However, apart from oxidative stress, diabetes duration and triglyceride levels are also related to the severity of PN.

Early oxidative stress in the diabetic kidney: effect of DL-alpha-lipoic acid.

Oxidative stress is implicated in the pathogenesis of diabetic nephropathy. The attempts to identify early markers of diabetes-induced renal oxidative injury resulted in contradictory findings. We characterized early oxidative stress in renal cortex of diabetic rats, and evaluated whether it can be prevented by the potent antioxidant, DL-alpha-lipoic acid. The experiments were performed on control rats and streptozotocin-diabetic rats treated with/without DL-alpha-lipoic acid (100 mg/kg i.p., for 3 weeks from induction of diabetes). Malondialdehyde plus 4-hydroxyalkenal concentration was increased in diabetic rats vs. controls (p <.01) and this increase was partially prevented by DL-alpha-lipoic acid. F(2) isoprostane concentrations (measured by GCMS) expressed per either mg protein or arachidonic acid content were not different in control and diabetic rats but were decreased several-fold with DL-alpha-lipoic acid treatment. Both GSH and ascorbate (AA) levels were decreased and GSSG/GSH and dehydroascorbate/AA ratios increased in diabetic rats vs. controls (p <.01 for all comparisons), and these changes were completely or partially (AA) prevented by DL-alpha-lipoic acid. Superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione transferase, and NADH oxidase, but not catalase, were upregulated in diabetic rats vs. controls, and these activities, except glutathione peroxidase, were decreased by DL-alpha-lipoic acid. In conclusion, enhanced oxidative stress is present in rat renal cortex in early diabetes, and is prevented by DL-alpha-lipoic acid.

Analysis of monohydroxyeicosatetraenoic acids and F2-isoprostanes as markers of lipid peroxidation in rat brain mitochondria.

We have introduced two specific techniques for the quantitative measurement of monohydroxyeicosatetraenoic acids (HETEs) and F2-isoprostanes by gas chromatography-mass spectrometry/negative ion chemical ionization (GC-MS/NICI) to study lipid peroxidation in isolated rat brain mitochondria by iron/ascorbate. The analysis of HETEs involved hydrogenation, solid phase extraction on a C18-cartridge, formation of pentafluorobenzyl bromide and trimethylsilyl ether derivatives. In the case of F2-isoprostanes, the analytical procedure was similar to that of HETEs except that the hydrogenation step was omitted. We found that HETE content (sum of 5-, 8-12-, and 15-isomers) in freshly prepared rat brain mitochondria was 220 +/- 40pmol/mg protein. The corresponding content for the F2-isoprostane, 8-iso-PGF2alpha, was 0.21 +/-+/- 0.10 pmol/mg protein. HETEs and 8-iso-PGF2alpha were predominantly present in the esterified form. The content of both HETEs and 8-iso-PGF2alpha were increased in presence of iron/ascorbate as oxidation system. After 30 min incubation with Fe2+ ascorbate, the content of HETE isomers was increased about 6-fold compared with baseline levels whereas that for 8-iso-PGF2alpha was elevated 100-fold. Formation of HETEs and F2-isoprostanes corresponded to the consumption of arachidonic acid (AA) and alpha-tocopherol, respectively. There were almost no changes in the content of free (non-esterified) HETEs and 8-iso-PGF2alpha during the course of iron/ascorbate induced oxidation of the brain mitochondria. Our data provide the first direct evidence for the presence of HETEs and F2-isoprostanes in freshly isolated rat brain mitochondria and that esterified HETEs and 8-iso-PGF2alpha are predominantly generated during iron/ascorbate induced lipid peroxidation. Sensitive quantification of these products of non-enzymatic lipid peroxidation as indicators of oxidant injury opens new areas of investigation regarding the role of free radicals in the pathogenesis of human diseases. In addition, HETEs and F2-isoprostanes may be important mediators for mitochondrial functions.