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Growing evidence suggests that overall and abdominal obesity might lead to oxidative stress (OxS), which, in turn, plays a key role in the pathogenesis of a wide spectrum of diseases. In this study, for the first time, we compared the correlations of indirect, i.e. anthropometric, and direct, by dual energy X-ray absorptiometry (DXA), measures of body fat with circulatory OxS markers in women. To address this issue, we assessed central and total body fat mass (FM) by DXA, and serum levels of advanced oxidation protein products (AOPP), thiols and hydroperoxides in 275 healthy women (age 21-65 years; body mass index [BMI] 21.1-32.0 kg/m(2); waist circumference [WC] 60.1-109.9 cm). Among the markers considered in the study, only hydroperoxides levels, i.e. by-products of lipid peroxidation, were significantly (p0.05 for all) and positively correlated to body fat accumulation after controlling for confounding factors. In particular, this marker was found to be similarly associated with DXA-derived total FM, total FM % and trunk FM as well as with WC. Of note, hydroperoxides appeared to be correlated with abdominal but not with general obesity, as classified according to standard WC and BMI cut-offs, respectively. In conclusion, taken together our data demonstrated that, at least in women, the measurement of body FM by DXA has no advantage over the simpler and cheaper WC with regard to their associations with systemic OxS markers. Moreover, WC emerged as a superior potential predictor of OxS compared to the other most commonly used anthropometric measures (including BMI and waist to hip ratio).

Background High-density lipoprotein (HDL)-bound paraoxonase-1 (PON-1) is mechanistically related to oxidative stress, inflammation and atherosclerosis and this multirole nature positions the enzyme as potential pathogenic player and candidate biomarker for many diseases. Our previous results suggest a significant derangement in redox balance already present in the prodromal stage of dementia and an association between decline serum PON-1 activities and conversion of mild cognitive impairment (MCI) to late onset Alzheimer’s disease (LOAD) or vascular dementia (VAD). Download : Download high-res image (185KB) Download : Download full-size image Aims 1) evaluate the role of PON-1 in a larger population, including patients with LOAD-VAD mixed dementia (MD); 2) explore a possible association between PON-1 and multiple sclerosis (MS); 3) evaluate if cerebrospinal fluid (CSF) levels of PON-1 activities might be useful biomarkers for MS. Results We found that serum arylesterase, but not paraoxonase, levels of PON-1 were significantly lower in patients affected by MCI (n=232), VAD (n=65), LOAD (n=175), MD (n=88) as well as those with MS (n=104) as compared to healthy controls. Notably, the most pronounced decline in this activity was shown by MD (-18%, p Conclusion Overall our data suggest that a depressed arylesterase activity could be a common denominator of different neurological diseases which, independently of their ethiopathogenesis and pathophysiology, appear to be all characterized by an altered systemic redox balance.

Retinal diseases (RD), including diabetic retinopathy, are among the most important eye diseases in industrialized countries. RD is characterized by abnormal angiogenesis associated with an increase in cell proliferation and apoptosis. Hypoxia could be one of the triggers of the pathogenic mechanism of this disease. A key regulatory component of the cell's hypoxia response system is hypoxia-inducible factor 1 alpha (HIF-1α). It has been demonstrated that the induction of HIF-1α expression can be also achieved in vitro by exposure with cobalt chloride (CoCl2), leading to an intracellular hypoxia-like state. In this study we have investigated the effects of CoCl2 on human retinal epithelium cells (hRPE), which are an integral part of the blood-retinal barrier, with the aim to determine the possible role of oxidative stress in chemical hypoxia-induced damage in retinal epithelial cells. Our data showed that CoCl2 treatment is able to induce HIF-1α expression, that parallels with the formation of reactive oxygen species (ROS) and the increase of lipid 8-isoprostanes and 4-hydroxynonenal (4-HNE) protein adducts levels. In addition we observed the activation of the redox-sensitive transcription factor nuclear factor-kappaB (NFkB) by CoCl2 which can explain the increased levels of vascular endothelial growth factor (VEGF). The increased number of dead cells seems to be related to an apoptotic process. Taken together these evidences suggest that oxidative stress induced by hypoxia might be involved in RD development through the stimulation of two key-events of RD such as neo-angiogenesis and apoptosis.

Abstract: 6-Phosphogluconate dehydrogenase catalyzes the oxidative decarboxylation of 6-phosphogluconate to ribulose 5-phosphate through an oxidation, a decarboxylation and a tautomerization. The two subunits in the crystals of the dimeric sheep liver enzyme have the same conformation, as the apoenzyme and with the substrate or coenzyme. An hypothesis is now advanced that in solution, during catalysis, the two subunits have a different alternating role and thus a functional asymmetry.

The aim of the present study was to investigate whether accumulation of central fat is correlated with systemic oxidative stress (OxS) in non-obese apparently healthy postmenopausal women. Serum parameters of OxS (hydroperoxides and non-enzymatic antioxidants) along with body fat distribution, as assessed by dual-energy-X-ray absorptiometry (DXA), were evaluated in 134 non-obese postmenopausal women. Multiple regression analysis showed that central (trunk) fat significantly correlated with both markers of OxS independently of confounding factors (i.e. BMI, smoking, age, hypertension, legs and arms fat mass). In specific, the standardized regression coefficient was positive for hydroperoxides (β = 0.324, p

The aim of the present study was to analyze the protein composition of ductal breast carcinoma and the surrounding normal tissue in individual patients using comparative 2D proteomics and mass spectrometry to detect candidate disease biomarkers for diagnosis and prognosis. Samples of normal and cancerous tissue obtained form 28 patients were analyzed. Chaperonins and cytoskeletal proteins predominated among the 11 proteins for which major changes in abundance were detected. Of these 11 proteins with an altered expression, 2 had a decreased expression and 9 had an increased expression. In addition, the abundance of a few cytokeratins was also altered; however, they were not capable of serving as specific circulatory biomarkers. The proteins which we observed to exhibit an altered expression in infiltrating ductal breast carcinoma may be exploited as novel targets for therapeutic interventions or represent novel diagnostic/prognostic markers for the early detection of aggressive tumors, particularly those with multridrug-resistant phenotypes during the earlier stages of the disease.

Background: Post-menopausal osteoporosis (PO) affecting a large fraction of elderly women, is triggered by the decline in 17β-estradiol (E2) level. Experimental studies in animal models and cell cultures have suggested that the fall in E2 might contribute to developing oxidative stress (OS) which in turn is believed to play an important role in PO pathogenesis. The scarcity of human studies focusing on this issue prompted us to investigate the effects of the reproductive and post-reproductive phase of women’s life on OS and bone health. Methods: Serum parameters of oxidative challenge (lipid hydroperoxides and protein advanced oxidation products) and antioxidant defence (total serum antioxidants levels) along with bone mineral density (BMD) at femoral neck and lumbar spine were assessed in a sample of 191 women (98 pre- and 93 post-menopausal, of whom 30 osteoporotic). Results: Pearson’s correlation analysis unveiled that spinal BMD was negatively correlated with lipid hydroperoxides in overall postmenopausal subsample (r=–0.251, p=0.012), while no significant link between these two variables was detected in women in reproductive age (r=–0.022, p=0.833). Noteworthy, stepwise multiple regression analysis showed that the association found in post-menopausal women retained significance after adjusting for potential confounding factors (p=0.001). Conclusions: Our data showed that markers of oxidative challenge are associated with bone loss in women in post-menopausal status. We suggest that menopause-related estrogen withdrawal might contribute to make bone more vulnerable to oxidative injury thereby increasing the risk of PO development.

The present study aimed to investigate any associations between parameters of body fat mass distribution and levels of serum uric acid (sUA), a well-documented cardiovascular risk factor, among non-obese women ranging from pre- to post-menopausal status.In this cross-sectional population-based study we assessed body fat distribution by dual-energy-X-ray absorptiometry (DXA), and sUA levels in 101 pre- and 134 post-menopausal non-obese apparently healthy women.Multivariate stepwise regression analysis revealed that sUA was independently associated to the indicators of overall fatness, i.e. body mass index (β=0.339, p0.001) and DXA-assessed total and percentage body fat (β=0.366, p0.001 and β=0.412, p0.001, respectively), only among post-menopausal women. Within this sample subset, trunk (i.e. central) fat mass emerged as a strong predictor of sUA (β=0.408, p0.001), after taking the potential confounders (including body mass index) into account.Central fat accumulation was found to be independently associated with higher sUA levels among non-obese women in post- but not among those in pre-menopause.

A large body of evidences obtained in human and animal brain tissue suggest a role of oxidative stress (OxS) in the pathogenesis of late onset Alzheimer's disease (LOAD); on the contrary, data on peripheral markers of OxS in LOAD are still controversial. We evaluated the serum levels of products of lipid peroxidation, hydroperoxides, advanced oxidation protein products, total and residual antioxidant power, thiols, and uric acid in a sample of 334 older individuals: 101 LOAD patients, 134 patients with mild cognitive impairment (MCI), and 99 controls. At univariate analysis, serum hydroperoxides were higher while residual antioxidant power was lower in MCI and LOAD compared with in controls. By multivariate logistic regression analysis we found that, compared with controls, high levels (over median value) of serum hydroperoxides were independently associated with an increase in the likehood of having MCI (Odd Ratio: 2.59, 95% Confidence Interval: 1.08-6.21) or LOAD (OR: 4.09, 95%CI: 1.36-11.81). Furthermore, low levels of residual antioxidant power (below the median value) were associated with increased risk of having MCI (OR: 3.97, 95% CI: 1.62-9.72), but not dementia (OR: 2.31, 95%CI: 0.83-6.63). Our study suggests that a systemic redox-imbalance leading to OxS might be associated not only with LOAD but also with MCI.

Subunit T of the native muscle troponin complex is a recognised substrate of transglutaminase both in vitro and in situ with formation of isopeptide bonds. Using a proteomic approach, we have now determined the precise site of in vitro labelling of the protein. A preparation of troponin purified from ether powder from mixed rabbit skeletal muscles was employed as transglutaminase substrate. The only isoform TnT2F present in our preparation was recognised as acyl-substrate by human type 2 transglutaminase which specifically modified glutamine 13 in the N-terminal region. During the reaction, the troponin protein complex was polymerized. Results are discussed in relation to the structure of the troponin T subunit, in the light of the role of troponins in skeletal and cardiac muscle diseases, and to the rules governing glutamine side chain selection by tissue transglutaminase.

The reductive carboxylation of ribulose-5-phosphate (Ru5P) by 6-phosphogluconate dehydrogenase (6PGDH) from Candida utilis was investigated using kinetic isotope effects. The intrinsic isotope effect for proton abstraction from Ru5P was found at 4.9 from deuterium isotope effects on V and V/K and from tritium isotope effects on V/K. The presence of 6-phosphogluconate (6PG) in the assay mixture changes the magnitude of the observed isotope effects. In the absence of 6PG (D)(V/K) and (D)(V) are 1.68 and 2.46, respectively, whereas the presence of 6PG increases (D)(V/K) to 2.84 and decreases (D)(V) to 1.38. A similar increase of (T)(V/K) is observed as 6PG builds up in the reaction mixture. These data indicate that in the absence of 6PG, a slow step, which precedes the chemical process, is rate-limiting for the reaction, whereas in the presence of 6PG, the rate-limiting step follows the isotope-sensitive step. Kinetic analysis of reductive carboxylation shows that 6PG at low concentrations decreases the K(m) of Ru5P, whereas at higher concentrations, the usual competitive pattern is observed. These data indicate that full activity of 6PGDH is achieved when one subunit carries out the catalysis and the other subunit carries an unreacted 6PG. Thus, 6PG is like an allosteric activator of 6PGDH.

The transamidating activity of tissue transglutaminase is regulated by the ligands calcium and GTP, via conformational changes which facilitate or interfere with interaction with the peptidyl-glutamine substrate. We have analysed binding of these ligands by calorimetric and computational approaches. In the case of GTP we have detected a single high affinity site (K (D) approximately 1 microM), with moderate thermal effects suggestive that binding GTP involves replacement of GDP, normally bound to the protein. On line with this possibility no significant binding was observed during titration with GDP and computational studies support this view. Titration with calcium at a high cation molar excess yielded a complex binding isotherm with a number of "apparent binding sites" in large excess over those detectable by equilibrium dialysis (6 sites). This binding pattern is ascribed to occurrence of additional thermal contributions, beyond those of binding, due to the occurrence of conformational changes and to catalysis itself (with protein self-crosslinking). In contrast only one site for binding calcium with high affinity (K (D) approximately 0.15 microM) is observed with samples of enzyme inactivated by alkylation at the active site (to prevent enzyme crosslinkage and thermal effects of catalysis). These results indicate an intrinsic ability of tissue transglutaminase to bind calcium with high affinity and the necessity of careful reassessment of the enzyme regulatory pattern in relation to the concentrations of ligands in living cells, taking also in account effects of ligands on protein subcellular compartimentation.

To investigate the role of menopause, body mass index (BMI) and aging on body fat distribution in women.In this population-based cross-sectional study, 335 women (126 in pre-menopause, 75 in peri-menopause and 134 in post-menopause according to Stages of Reproductive Aging Workshop criteria) were evaluated for body mass composition and fat distribution by dual X-ray absorptiometry procedure. A sub-group of 79 women with similar age and BMI was extracted from the sample to examine the relative influence of BMI in body fat distribution.ANCOVA analysis of total sample showed an age-independent increase of total fat mass (p0.001) and percentage on total weight (p0.001), arms fat mass (p0.01), legs fat mass percentage on total fat (p0.05) and trunk fat mass (p0.001) and percentage (p0.05) in peri- and post- with respect to pre-menopausal women. In the sub-sample including age and BMI matched women the difference of regional fat parameters among menopausal status was no more statistically significant.BMI, and not age, is the main determinant of the increase of body fat mass (total and abdominal) observed during the menopausal transition.

To evaluate the role of menopause on the regional composition and distribution of fat in women and eventual correlations with the oxidative state.In this observational clinical investigation, 90 women (classified for menopause status according to Stages of Reproductive Aging Workshop criteria) were evaluated for body mass composition and fat distribution by dual-energy x-ray absorptiometry and for oxidative status by determination of serum hydroperoxide levels and residual antioxidant activity.Total body fat mass increases significantly in postmenopause (P0.05) by 22% in comparison with premenopause, with specific increases in fat deposition at the level of trunk (abdominal and visceral) (P0.001) and arms (P0.001). Concomitantly, the antioxidant status increases significantly (P0.001) by 17%. When data were adjusted for age by analysis of covariance, statistical significance disappeared for the increase in fat mass, but it was retained for antioxidant status (P0.05). Both antioxidant status and hydroperoxide level increased with trunk fat mass, as shown by linear correlation analysis (r = 0.46, P0.001 and r = 0.26, P0.05, respectively).The results of our investigation demonstrate that fat content increases in the upper part of the body (trunk and arms) in postmenopause and that age is the main determinant of this increase. During the comparison of premenopausal and postmenopausal women, we also detected a significant increase in antioxidant status. Apparently this change is mainly related to menopausal endocrine and fat changes.

6-Phosphogluconate dehydrogenase is a potential target for new drugs against African trypanosomiasis. Phosphorylated aldonic acids are strong inhibitors of 6-phosphogluconate dehydrogenase, and 4-phospho-d-erythronate (4PE) and 4-phospho-d-erythronohydroxamate are two of the strongest inhibitors of the Trypanosoma brucei enzyme. Binding of the substrate 6-phospho-d-gluconate (6PG), the inhibitors 5-phospho-d-ribonate (5PR) and 4PE, and the coenzymes NADP, NADPH and NADP analogue 3-amino-pyridine adenine dinucleotide phosphate to 6-phospho-d-gluconate dehydrogenase from T. brucei was studied using isothermal titration calorimetry. Binding of the substrate (K(d) = 5 microm) and its analogues (K(d) =1.3 microm and K(d) = 2.8 microm for 5PR and 4PE, respectively) is entropy driven, whereas binding of the coenzymes is enthalpy driven. Oxidized coenzyme and its analogue, but not reduced coenzyme, display a half-site reactivity in the ternary complex with the substrate or inhibitors. Binding of 6PG and 5PR poorly affects the dissociation constant of the coenzymes, whereas binding of 4PE decreases the dissociation constant of the coenzymes by two orders of magnitude. In a similar manner, the K(d) value of 4PE decreases by two orders of magnitude in the presence of the coenzymes. The results suggest that 5PR acts as a substrate analogue, whereas 4PE mimics the transition state of dehydrogenation. The stronger affinity of 4PE is interpreted on the basis of the mechanism of the enzyme, suggesting that the inhibitor forces the catalytic lysine 185 into the protonated state.

The diatomic molecule of oxygen contains two uncoupled electrons and can therefore undergo reduction, yielding several different oxygen metabolites, which are collectively called Reactive Oxygen Species or ROS. They are invariably produced in aerobic environments through a variety of mechanisms, which include electron "leakage" during biologic oxidations, action of flavin dehydrogenases and specific membrane associated secretion, as well as by physical activation of oxygen by irradiation, e.g. UV sun-light. Organisms have developed efficient protective mechanisms against excessive accumulation of ROS, which include superoxide anion, hydrogen peroxide and hydroxyl radical, since all these metabolites are highly reactive and affect almost every kind of organism, either directly or through conversion into other derivatives, notably NO-derived radicals or RNS. Depending on their tissue concentration they can either exert beneficial physiologic effects (control of gene expression and mitogenesis) or damage cell structures, including lipids and membranes, proteins and nucleic acids, leading to cell death. In this brief overview we summarize the present state-of-the-art, restricting the discussion to the role of ROS in physiology and pathology, not taking into account RNS. Discussion will focus on basic chemical and biochemical features of ROS, underlining how ROS can promote severe diseases, including neoplastic, cardiovascular and neurodegenerative diseases. This brief discussion should clarify the present huge interest in ROS, in the perspective to develop new and specific therapeutic approaches.

Purified bile salt hydrolase from bile-adapted Xanthomonas maltophilia displays Michaelis-Menten kinetics on cholylglycine and cholyltaurine and hydrolyzes bile salts also in crude bovine bile. The protein is a dimer and is resistant to proteinases and to heating at 55 to 60°C for up to 60 min, in agreement with calorimetric data.

Objective At present, there is growing demand for alternative, or additional, treatments to hormone replacement therapy for menopause-related hot flashes (HF). Antioxidant supplements have been recently proposed as possible candidates for this purpose, regardless of the absence of clear evidence in support of a link between these vasomotor symptoms and oxidative stress (OxS). The aim of our study was to evaluate the association between HF and OxS serum markers in a large sample of middle-aged women. Materials and methods We conducted a cross-sectional study on 245 perimenopausal and early postmenopausal women (age 45–60 years). The variables examined were presence of self-reported HF and levels of 8-iso-prostaglandin F2α, 8-OH-deoxy-2′-guanosine, advanced oxidation protein products, total antioxidant power, uric acid, thiols, and paroxonase-1. Results Seventy-six women (31%) reported to suffer from HF (either medium or high intensity). None of the peripheral markers of OxS examined was found to be significantly associated with the presence of HF. Conclusion Taken together, our data suggest that systemic OxS might not be implicated with the onset of the climacteric vasomotor symptoms that most commonly affect women experiencing perimenopause and early postmenopause.

Background: The prevalence and prognostic implications of metabolic syndrome (MetS) in patients infected by the SARS-CoV-2 remain unclear. We performed a systematic review and meta-analysis of prevalence and mortality risk in COVID-19 patients with MetS. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in abstracting data and assessing validity. We searched MEDLINE and Scopus to locate every article published up to 1 September 2021, reporting data on MetS among COVID-19 patients. The pooled prevalence of MetS was calculated using a random effects model and presented using the related 95% confidence interval (CI), while the mortality risk was estimated using the Mantel-Haenszel random effects models with odds ratio (OR) and related 95% CI. Statistical heterogeneity was measured using the Higgins I2 statistic. Results: Six studies, enrolling 209.569 COVID-19 patients [mean age 57.2 years, 114.188 males (54.4%)] met the inclusion criteria and were included in the final analysis. The pooled prevalence of dyslipidaemia was 20.5% of cases (95% CI: 6.7–47.8%, p = 0.03), with high heterogeneity (I2 = 98.9%). Pre-existing MetS was significantly associated with higher risk of short-term mortality (OR: 2.30, 95% CI: 1.52–3.45, p < 0.001), with high heterogeneity (I2 = 89.4%). Meta-regression showed a direct correlation with male gender (p = 0.03), hypertension (p < 0.001), DM (p = 0.01) and hyperlipidaemia (p = 0.04), but no effect when considering age (p = 0.75) and chronic pulmonary disease (p = 0.86) as moderators. Conclusions: MetS represents a major comorbidity in about 20% of COVID-19 patients and it is associated with a 230% increased risk of short-term mortality.