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Aims: Mitochondrial dysfunction and inflammation are at the core of axonal degeneration in several multifactorial neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease, and Parkinson's disease. The transcriptional coregulator RIP140/NRIP1 (receptor-interacting protein 140) modulates these functions in liver and adipose tissue, but its role in the nervous system remains unexplored. Here, we investigated the impact of RIP140 in the Abcd1- mouse model of X-linked adrenoleukodystrophy (X-ALD), a genetic model of chronic axonopathy involving the convergence of redox imbalance, bioenergetic failure, and chronic inflammation. Methods and results: We provide evidence that RIP140 is modulated through a redox-dependent mechanism driven by very long-chain fatty acids (VLCFAs), the levels of which are increased in X-ALD. Genetic inactivation of RIP140 prevented mitochondrial depletion and dysfunction, bioenergetic failure, inflammatory dysregulation, axonal degeneration and associated locomotor disabilities in vivo in X-ALD mouse models. Conclusions: Together, these findings show that aberrant overactivation of RIP140 promotes neurodegeneration in X-ALD, underscoring its potential as a therapeutic target for X-ALD and other neurodegenerative disorders that present with metabolic and inflammatory dyshomeostasis. This study was funded by the Institute of Health Carlos III through projects FIS PI14/01115 and FIS PI17/00134 to M.P.O., FIS PI13/00584 and FIS PI14/00328 to R.P., FIS PI19/0108 to S.F., and FIS PI14/00410, FIS PI17/00916, and FIS PI20/00759 to A.P. and was co-funded by the European Regional Development Fund (ERDF, a way to build Europe). This study was funded by the Institute of Health Carlos III through grants PFIS FI12/00457 to P.R-R. and Miguel Servet program CPII16/00016 to S.F. and co-funded by the European Social Fund (ESF, investing in your future). This study was supported by the European Commission (FP7-241622 to A.P.); the Autonomous Government of Catalonia (2014SGR168 to R.P. and 2017SGR1206 to A.P.); and the Center for Biomedical Research on Rare Diseases (CIBERER), an initiative of the Institute of Health Carlos III (M.R.). Locomotor experiments were performed by the SEFALer unit F5 led by A.P., which belongs to the CIBERER structure. We thank the CERCA Program/Generalitat de Catalunya for institutional support.

Introduccion. Entre los principales componentes lipidicos de las membranas celulares se encuentran los glicerofosfolipidos (GFL), que se sintetizan en una via de novo a partir del diacilglicerol (DAG). El perfil lipidico es una caracteristica optimizada asociada con la longevidad animal. En este contexto, hipotetizamos que la tasa de biosintesis de DAGs y, por extension, de GFL, guarda una relacion con la longevidad de una especie animal. Material y metodos. Se realiza un analisis lipidomico basado en espectrometria de masas del plasma de 11 especies de mamiferos que cubren un rango de longevidad maxima de 3,5 a 120 anos. La identificacion de especies lipidicas se basa en masa exacta, tiempo de retencion y distribucion isotopica. Se aplica un test ANOVA para obtener las especies lipidicas diferenciales entre las especies y la correlacion de Spearman para establecer su asociacion con la longevidad. Los analisis estadisticos se realizaron con el programa SPSS y el software para el analisis metabolomico Metaboanalyst. Resultados. Entre las 1061 especies moleculares lipidicas diferenciales se identifican 47 DAGs, 14 de los cuales presentan una correlacion significativa y negativa con la longevidad animal. El analisis multivariante muestra que solamente con estos 14 DAGs somos capaces de discriminar una especie animal y su longevidad maxima. Conclusiones. Estos resultados sugieren que las especies longevas tienen una menor tasa de biosintesis de novo de GFL, posiblemente asociada a una menor tasa de recambio de los lipidos de membrana, lo que conllevaria un menor coste energetico.

Oxidative damage and inflammation coexist in healthy human brain aging. The present study analyzes levels of protein adduction by lipid peroxidation (LP) end-products neuroketal (NKT) and malondialdehyde (MDA), as markers of protein oxidative damage, cycloxygenase-2 (COX-2) levels, as a marker of inflammation, and cytochrome P450 2J2 (CYP2J2), responsible of generation of neuroprotective products, in twelve brain regions in normal middle-aged individuals (MA) and old-aged (OA) individuals. In addition, levels of these markers were evaluated as a function of age as a continuous variable and correction for multiple comparisons. Selection of regions was based on their different vulnerability to prevalent neurodegenerative diseases in aging. Our findings show region-dependent LP end-products, COX-2 and CYP2J2 changes in the aging human brain. However, no clear relationship can be established between NKT, MDA, COX-2 and CYP2J2 levels, and regional vulnerability to neurodegeneration in old age.

Maximum longevity (ML) varies significantly across animal species, but the underlying molecular mechanisms remain poorly understood. Recent studies and omics approaches suggest that phenotypic traits of ML could to converge in the mammalian target of rapamycin (mTOR) signalling pathway. The present study is a comparative approach using heart tissue from 8 mammalian species with a ML ranging from 3.5 to 46 years. Gene expression, protein content, and concentration of regulatory metabolites of the mTOR complex 1 (mTORC1) were measured using droplet digital PCR, western blot and mass spectrometry, respectively. Our results demonstrate 1) the existence of differences species-specific in gene expression and protein content of mTORC1; 2) that the achievement of a longevity phenotype requires decreased and inhibited mTORC1; 3) decreased content of mTORC1 activators in long-lived animals, and 4) independence of phylogeny relationships on these changes. Altogether, our findings support mTORC1 down-regulation to achieve a longevous phenotype. This work was supported by the Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (grant number PI14/00328), the Spanish Ministry of Science, Innovation and Universities (RTI2018-099200-B-I00), and the Generalitat of Catalonia, Agency for Management of University and Research Grants (2017SGR696) and Department of Health (SLT002/16/00250) to R.P. This study has been co-financed by FEDER funds from the European Union (“A way to build Europe”).

Aging is a multifactorial process which affects all animals. Aging as a result of damage accumulation is the most accepted explanation but the proximal causes remain to be elucidated. There is also evidence indicating that aging has an important genetic component. Animal species age at different rates and specific signaling pathways, such as insulin/insulin-like growth factor, can regulate life span of individuals within a species by reprogramming cells in response to environmental changes. Here, we use an unbiased approach to identify novel factors that regulate life span in Drosophila melanogaster. We compare the transcriptome and metabolome of two wild-type strains used widely in aging research: short-lived Dahomey and long-lived Oregon R flies. We found that Dahomey flies carry several traits associated with short-lived individuals and species such as increased lipoxidative stress, decreased mitochondrial gene expression, and increased Target of Rapamycin signaling. Dahomey flies also have upregulated octopamine signaling known to stimulate foraging behavior. Accordingly, we present evidence that increased foraging behavior, under laboratory conditions where nutrients are in excess increases damage generation and accelerates aging. In summary, we have identified several new pathways, which influence longevity highlighting the contribution and importance of the genetic component of aging., This work was supported by the European Research Council (260632 - ComplexI&Aging to A.S.); the Academy of Finland (252048 to A.S); the Biotechnology and Biological Sciences Research Council (BB/M023311/1 to A.S.); the Centre for International Mobility (CIMO) (TM-12–8391 and TM-13–8919 to N.G.); the Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (PI14/00328 to R.P. and PI17/01286 to P.N.); the Autonomous Government of Catalonia (2017SGR696 and SLT002/16/00250 to R.P.); the Ministry of Education and Science of Ukraine (grant number 0117U006426 to O.L.); FEDER funds from the European Union (“A way to build Europe” to R.P.); and the Doctoral Programme in Medicine and Life Sciences of University of Tampere (to T.R). R.S is a Sir Henry Wellcome Postdoctoral Fellow funded by Wellcome (204715/Z/16/Z).

// Mariona Jove 1, * , Irene Pradas 1, * , Alba Naudi 1, * , Susana Rovira-Llopis 2 , Celia Banuls 2 , Milagros Rocha 2 , Manuel Portero-Otin 1 , Antonio Hernandez-Mijares 2, 3, 4, # , Victor M. Victor 2, 5, # and Reinald Pamplona 1, # 1 Department of Experimental Medicine, Lleida University-Institute for Research in Biomedicine of Lleida (UdL-IRBLleida), 25198 Lleida, Spain 2 Foundation for the Promotion of Healthcare and Biomedical Research in the Valencian Community (FISABIO), Service of Endocrinology, University Hospital Dr. Peset, 46017 Valencia, Spain 3 Fundacion Investigacion Hospital Clinico Universitario/INCLIVA, Valencia University, 46010 Valencia, Spain 4 Department of Medicine, Valencia University, 46010 Valencia, Spain 5 Department of Physiology, Valencia University, 46010 Valencia, Spain * These authors contributed equally to this work # These authors share co-senior authorship Correspondence to: Victor M. Victor, email: victor.victor@uv.es Reinald Pamplona, email: reinald.pamplona@mex.udl.cat Keywords: cell signaling molecules; glycerophospholipids; free fatty acids; lipidomics; lipid de novo biosynthesis Received: October 03, 2017 Accepted: December 04, 2017 Published: December 17, 2017 ABSTRACT Purpose: In this work, a non-targeted approach was used to unravel changes in the plasma lipidome of PCOS patients. The aim is to offer new insights in PCOS patients strictly selected in order to avoid confounding factors such as dyslipemia, obesity, altered glucose/insulin metabolism, cardiovascular disease, or cancer. Results: Multivariate statistics revealed a specific lipidomic signature for PCOS patients without associated pathologies. This signature implies changes, mainly by down-regulation, in glycerolipid, glycerophospholipid and sphingolipid metabolism suggesting an altered biosynthetic pathway of glycerophospholipids and cell signaling as second messengers in women with PCOS. Conclusions: Our study confirms that a lipidomic approach discriminates a specific phenotype from PCOS women without associated pathologies from healthy controls. Methods: In a cross-sectional pilot study, data were obtained from 34 subjects, allocated to one of two groups: a) lean, healthy controls ( n = 20), b) PCOS patients ( n = 14) with diagnosis based on hyperandrogenaemia, oligo-anovulation and abnormal ovaries with small follicular cysts. A detailed biochemical characterization was made and lipidomic profiling was performed via an untargeted approach using LC-ESI-QTOF MS/MS.

X-Adrenoleukodystrophy (X-ALD) and its adult-onset, most prevalent variant adrenomyeloneuropathy (AMN) are caused by mutations in the peroxisomal transporter of the very long-chain fatty acid ABCD1. AMN patients classically present spastic paraparesis that can progress over decades, and a satisfactory treatment is currently lacking. Oxidative stress is an early culprit in X-ALD pathogenesis. A combination of antioxidants halts the clinical progression and axonal damage in a murine model of AMN, providing a strong rationale for clinical translation. In this phase II pilot, open-label study, 13 subjects with AMN were administered a high dose of α-tocopherol, N-acetylcysteine, and α-lipoic acid in combination. The primary outcome was the validation of a set of biomarkers for monitoring the biological effects of this and future treatments. Functional clinical scales, the 6-minute walk test (6MWT), electrophysiological studies, and cerebral MRI served as secondary outcomes. Most biomarkers of oxidative damage and inflammation were normalized upon treatment, indicating an interlinked redox and inflammatory homeostasis. Two of the inflammatory markers, MCP1 and 15-HETE, were predictive of the response to treatment. We also observed a significant decrease in central motor conduction time, together with an improvement or stabilization of the 6MWT in 8/10 subjects. This study provides a series of biomarkers that are useful to monitor redox and pro-inflammatory target engagement in future trials, together with candidate biomarkers that may serve for patient stratification and disease progression, which merit replication in future clinical trials. Moreover, the clinical results suggest a positive signal for extending these studies to phase III randomized, placebo-controlled, longer-term trials with the actual identified dose. ClinicalTrials.gov Identifier: NCT01495260. This study was funded by grants from the Spanish Ministry of Health, Social Services and Equality (EC10-137), the Spanish Institute Health Carlos III (ICI14/0076) (co-funded by European Regional Development Fund, a way to build Europe), the Hesperia Foundation, the European Commission (Leukotreat FP7-241622), and the Autonomous Government of Catalonia (2014SGR1430; 2017SGR1206) to Aurora Pujol. Montserrat Ruiz was funded by the Center for Biomedical Research on Rare Diseases, an initiative of the Institute of Health Carlos III. Stéphane Fourcade was funded by Miguel Servet Program (CPII16/00016) (co-funded by European Social Fund, investing in your future). Alba Naudí, Manuel Portero-Otín, and Reinald Pamplona have received funding support from the Spanish Ministry of Science and Innovation (BFU2009-11879/BFI).

Objective: This study aimed to characterize the differences in protein oxidation biomarkers in adipose tissue (AT) as an indicator of AT metabolism and bariatric surgery weight‐loss success. Methods: A human model, in which sixty‐five individuals with obesity underwent bariatric surgery, and a diet‐induced obesity animal model, in which animals were treated for 2 months with normocaloric diets, were analyzed to determine the associations between AT protein oxidation and body weight loss. Protein oxidative biomarkers were determined by gas chromatography/mass spectrometry in AT from human volunteers before the surgery, as well as 2 months after a diet treatment in the animal model. Results: The levels of carboxyethyl‐lysine (CEL) and 2‐succinocystein (2SC) in both visceral and subcutaneous AT before the surgery directly correlated with greater weight loss in both human and animal models. 2SC levels in subcutaneous AT greater than 4.7 × 106 μmol/mol lysine (95% CI: 3.4 × 106 to 6.0 × 106) may predict greater weight loss after bariatric surgery (receiver operating characteristic curve area = 0.8222; P = 0.0047). Additionally, it was observed that individuals with diabetes presented lower levels of CEL and 2SC in subcutaneous AT (P = 0.0266 and P = 0.0316, respectively) compared with individuals without diabetes. Conclusions: CEL and 2SC in AT are useful biomarkers of AT metabolism and predict the individual's ability to reduce body weight after bariatric surgery. This research was supported by the Spanish National Health Institute (Instituto de Salud Carlos III) Grant Number PI15/00332 and PI17/00134.

Ethnopharmacological relevance Ginseng is a widely used ingredient in several traditional Chinese medicine formulation, mainly as a prophylactic and restorative agent. Ginseng's Chinese traditional formulations have shown protective effects against atherosclerosis, suggesting that ginseng may be useful for the treatment of metabolic disorders. Aim of the study To evaluate whether the supplementation with Panax ginseng (PG) has an effect on blood lipid profile in humans. Materials and methods A meta-analysis and a systematic review were conducted to evaluate the effects of PG on blood lipid profile. Results A total of 18 studies met the inclusion criteria, from which 10 studies were performed in volunteers with at least one component of metabolic syndrome, 3 in postmenopausal women, 2 in healthy volunteers and 3 with other types of inclusion criteria. The doses employed ranged from 0.2 to 20 g/day (median 3 g/day, 95% CI 1.7, 5.8), while the treatment time ranged from 2 to 12 weeks (median 8 weeks, 95% CI 6, 9). Few studies reported the composition of the PG extract employed. The main ginsenosides reported were Rb1 and Rg1 (content ranging from Rb1 0.023-6.44 mg/g and Rg1 0.028-3.21 mg/g). Significant modification in blood profile was described in 7 studies, in which 5 studies observed a reduction in total cholesterol, 4 in LDL-cholesterol, and 2 in triacylglycerides. The meta-analysis of 10 studies in volunteers with parameters related with metabolic syndrome describes that PG may induce a mean difference compared to a placebo of −2.30 (95% CI -3.79,-0.80) and −1.47 (95% CI -1.90,-1.05) mg/dL per g/day of PG in the levels of total and LDL-cholesterol, with no significant effects in HDL-cholesterol and triacylglycerides. Conclusions PG extract may induce an improvement in blood lipid profile mainly by a reduction in total and LDL-cholesterol levels.

Tau P301S transgenic mice (PS19 line) are used as a model of frontotemporal lobar degeneration (FTLD)-tau. Behavioral alterations in these mice begin at approximately 4 months of age. We analyzed molecular changes related to disease progression in these mice. Hyperphosphorylated 4Rtau increased in neurons from 1 month of age in entorhinal and piriform cortices to the neocortex and other regions. A small percentage of neurons developed an abnormal tau conformation, tau truncation, and ubiquitination only at 9/10 months of age. Astrocytosis, microgliosis, and increased inflammatory cytokine and immune mediator expression also occurred at this late stage; hippocampi were the most markedly affected. Altered mitochondrial function, increased reactive oxygen species production, and limited protein oxidative damage were observed in advanced disease. Tau oligomers were only present in P301S mice, they were found in somatosensory cortex and hippocampi at the age of 3 months, and they increased across time in the somatosensory cortex and were higher and sustained in hippocampi. Age-related modifications in lipid composition occurred in both P301S and wild-type mice with regional and phenotypic differences; however, changes of total lipids did not seem to have pathogenic implications. Apoptosis only occurred in restricted regions in late disease. The complex tau pathology, mitochondrial alterations, oxidative stress damage, glial reactions, neuroinflammation, and cell death in P301S mice likely parallel those in FTLD-tau. Thus, therapies should focus first on abnormal tau rather than secondary events that appear late in the course of FTLD-tau.

Fatty acids are key components in the structural diversity of lipids and play a strategic role in the functional properties of lipids which determine the structural and functional integrity of neural cell membranes, the generation of lipid signaling mediators, and the chemical reactivity of acyl chains. The present study analyzes the profile of lipid fatty acid composition of membranes of human frontal cortex area 8 in individuals ranging from 40 to 90 years old. Different components involved in polyunsaturated fatty acid biosynthesis pathways, as well as adaptive defense mechanisms involved in the lipid-mediated modulation of inflammation, are also assessed. Our results show that the lipid profile in human frontal cortex is basically preserved through the adult life span to decay at advanced ages, which is accompanied by an adaptive proactive anti-inflammatory response possibly geared to ensuring cell survival and function.

The nuclear factor erythroid 2-like 2 (NRF2) is the master regulator of endogenous antioxidant responses. Oxidative damage is a shared and early-appearing feature in X-linked adrenoleukodystrophy (X-ALD) patients and the mouse model (Abcd1 null mouse). This rare neurometabolic disease is caused by the loss of function of the peroxisomal transporter ABCD1, leading to an accumulation of very long-chain fatty acids and the induction of reactive oxygen species of mitochondrial origin. Here, we identify an impaired NRF2 response caused by aberrant activity of GSK-3b. We find that GSK-3b inhibitors can significantly reactivate the blunted NRF2 response in patients’ fibroblasts. In the mouse models (Abcd1 and Abcd1 /Abcd2 / mice), oral administration of dimethyl fumarate (DMF/BG12/Tecfidera), an NRF2 activator in use for multiple sclerosis, normalized (i) mitochondrial depletion, (ii) bioenergetic failure, (iii) oxidative damage, and (iv) inflammation, highlighting an intricate cross-talk governing energetic and redox homeostasis in XALD. Importantly, DMF halted axonal degeneration and locomotor disability suggesting that therapies activating NRF2 hold therapeutic potential for X-ALD and other axonopathies with impaired GSK- 3b/NRF2 axis. This study was supported by grants from the Spanish Institute for Health Carlos III and “Fondo Europeo de Desarrollo Regional (FEDER), Union Europea, una manera de hacer Europa” [PFIS FI12/00457] to P.R-R., [FIS PI14/ 01115, FIS PI17/00134] to M.P.O., [FIS PI13/00584, FIS PI14/00328] to R.P., [FIS PI11/01043, FIS PI14/00410, FIS PI17/00916] to A.P., [Miguel Servet program CP11/00080, CPII16/00016, FIS PI15/00857] to S.F.; the European Commission [FP7-241622] to A.P., the European Leukodystrophy Association [ELA2012-033C1] to A.P; the Autonomous Government of Catalonia [SGR 2017SGR696] to R.P. and [SGR 2014SGR1430; 2017SGR1206] to A.P.; and the Centre for Biomedical Research on Rare Diseases (CIBERER) to N.L. and M.R. Locomotor experiments were performed by the SEFALer unit F5 (CIBERER) led by A.P.

Objective:The aim of this study was to investigate the usefulness of Alzheimer’s disease Cerebrospinal Fluid (CSF) biomarkers in predicting the progression to dementia in patients with Mild Cognitive Impairment (MCI).Methods:One hundred and thirteen patients were consecutively recruited from April 2012 to April 2014. Measurement of CSF biomarkers (amyloid-β42 (Aβ42), total tau (t-tau) and phosphorylated tau (p-tau)) and a neuropsychological evaluation were performed for all patients. We categorized patients with MCI as A+A- and N+N- based on the presence/absence of amyloid pathology and neurodegeneration, respectively.Results:Of 72 patients with MCI, 26 (36%) progressed to dementia. These patients had lower CSF Aβ42 levels and higher p-tau and t-tau levels at baseline. The proportion that progressed to dementia was 14.3% (2/14), 36.8% (7/19), 66.7% (4/6) and 75% (12/16) in the A-N-, A+N-, A-N+ (SNAP), and A+N+ patients, respectively (p < 0.05). There were significant differences in the probability of progression from amnestic MCI (aMCI) to AD between the A+N+ and A-N- patients (OR = 8.1, 95% CI 1.5-42.3, p = 0.001) but not between SNAP (OR = 7.3, 95% CI 0.9-61, p = 0.02) or A+N- (OR = 2.1, 95% CI 0.4 to 10.4, p = 0.15) patients compared to the A-N- subgroup. None of the biomarker profiles of the subgroups predicted the time until the progression to AD.Conclusion:The use of CSF AD biomarkers in clinical practice improves the certainty of diagnosis and prognosis of patients, especially in patients in the prodromal phase or in patients with atypical presentations.

The evolution of lifespan is a central question in evolutionary biology, begging the question why there is so large variation among taxa. Specifically, a central quest is to unravel proximate causes of ageing. Here, we show that the degree of unsaturation of liver fatty acids predicts maximum lifespan in 107 bird species. In these birds, the degree of fatty acid unsaturation is positively related to maximum lifespan across species. This is due to a positive effect of monounsaturated fatty acid content, while polyunsaturated fatty acid content negatively correlates with maximum lifespan. Furthermore, fatty acid chain length unsuspectedly increases with maximum lifespan independently of degree of unsaturation. These findings tune theories on the proximate causes of ageing while providing evidence that the evolution of lifespan in birds occurs in association with fatty acid profiles. This suggests that studies of proximate and ultimate questions may facilitate our understanding of these central evolutionary questions.

A molecular description of the mechanisms by which aging is produced is still very limited. Here, we have determined the plasma metabolite profile by using high-throughput metabolome profiling technologies of 150 healthy humans ranging from 30 to 100 years of age. Using a nontargeted approach, we detected 2,678 metabolite species in plasma, and the multivariate analyses separated perfectly two groups indicating a specific signature for each gender. In addition, there is a set of gender-shared metabolites, which change significantly during aging with a similar tendency. Among the identified molecules, we found vitamin D2-related compound, phosphoserine (40:5), monoacylglyceride (22:1), diacylglyceride (33:2), and resolvin D6, all of them decreasing with the aging process. Finally, we found three molecules that directly correlate with age and seven that inversely correlate with age, independently of gender. Among the identified molecules (6 of 10 according to exact mass and retention time), we found a proteolytic product (l-γ-glutamyl-l-leucine), which increased with age. On the contrary, a hydroxyl fatty acid (25-hydroxy-hexacosanoic), a polyunsaturated fatty acid (eicosapentaenoic acid), two phospholipids (phosphocholine [42:9]and phosphoserine [42:3]) and a prostaglandin (15-keto-prostaglandin F2α) decreased with aging. These results suggest that lipid species and their metabolism are closely linked to the aging process.

Oxidative stress and mitochondrial failure are prominent factors in the axonal degeneration process. In this study, we demonstrate that sirtuin 1 (SIRT1), a key regulator of the mitochondrial function, is impaired in the axonopathy and peroxisomal disease X-linked adrenoleukodystrophy (X-ALD). We have restored SIRT1 activity using a dual strategy of resveratrol treatment or by the moderate transgenic overexpression of SIRT1 in a X-ALD mouse model. Both strategies normalized redox homeostasis, mitochondrial respiration, bioenergetic failure, axonal degeneration and associated locomotor disabilities in the X-ALD mice. These results indicate that the reactivation of SIRT1 may be a valuable strategy to treat X-ALD and other axonopathies in which the control of redox and energetic homeostasis is impaired. This work was supported by grants from the European Commission [FP7-241622], the Spanish Institute for Health Carlos III [FIS PI11/01043], the Oliver’s Army Foundation, the Government of Catalonia [2009SGR85 to AP], the Spanish Institute for Health Carlos III [Miguel Servet program CP11/00080 to S.F.], the European Leukodystrophy Association (ELA) [ELA 2010-020F1 to SF, ELA 2013-003F1 to LM], the Spanish Ministry of Education [FPU program AP2008-03728 to LM]. JG held an IDIBELL PhD fellowship. The studies conducted at the Experimental Medicine Department were supported in part by R+D grants from the Spanish Ministry of Science and Innovation [BFU2009-11879/BFI], the Spanish Ministry of Health [PI081843, PI1300584], the Government of Catalonia [2009SGR735], the 'La Caixa' Foundation and COST B35 Action of the European Union. CIBERER and CIBERNED are initiatives of the Spanish Institute for Health Carlos III.

Human brain aging is the physiological process which underlies as cause of cognitive decline in the elderly and the main risk factor for neurodegenerative diseases such as Alzheimer's disease. Human neurons are functional throughout a healthy adult lifespan, yet the mechanisms that maintain function and protect against neurodegenerative processes during aging are unknown. Here we show that protein oxidative and glycoxidative damage significantly increases during human brain aging, with a breakpoint at 60 years old. This trajectory is coincident with a decrease in the content of the mitochondrial respiratory chain complex I–IV. We suggest that the deterioration in oxidative stress homeostasis during aging induces an adaptive response of stress resistance mechanisms based on the sustained expression of REST, and increased or decreased expression of Akt and mTOR, respectively, over the adult lifespan in order to preserve cell neural survival and function. R.C. received predoctoral fellowships from the Autonomous Government of Catalonia. We thank T. Yohannan for editorial help. Research reported in this publication was supported by the Spanish Ministry of Economy and Competitiveness, Institute of Health Carlos III (FIS Grants PI14/00757 and PI14/00328), and the Autonomous Government of Catalonia (2014SGR69 and 2014SGR168) to I.F. and R.P. This study was co-financed by FEDER funds from the European Union (‘a way to build Europe’).

Neurons in the mature human central nervous system (CNS) perform a wide range of motor, sensory, regulatory, behavioral, and cognitive functions. Such diverse functional output requires a great diversity of CNS neuronal and non-neuronal populations. Metabolomics encompasses the study of the complete set of metabolites/low-molecular-weight intermediates (metabolome), which are context-dependent and vary according to the physiology, developmental state, or pathologic state of the cell, tissue, organ, or organism. Therefore, the use of metabolomics can help to unravel the diversity-and to disclose the specificity-of metabolic traits and their alterations in the brain and in fluids such as cerebrospinal fluid and plasma, thus helping to uncover potential biomarkers of aging and neurodegenerative diseases. Here, we review the current applications of metabolomics in studies of CNS aging and certain age-related neurodegenerative diseases such as Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis. Neurometabolomics will increase knowledge of the physiologic and pathologic functions of neural cells and will place the concept of selective neuronal vulnerability in a metabolic context.

Resumen Introduccion El concepto de «vulnerabilidad neuronal selectiva» se refiere a la diferente sensibilidad de las poblaciones neuronales del sistema nervioso frente a diversos procesos que causan dano o muerte celular y que conllevan la neurodegeneracion. Dado que el estres oxidativo desempena un papel crucial en el proceso fisiologico de envejecimiento y este se invoca como un mecanismo etiopatogenico y/o fisiopatologico de la neurodegeneracion, en el presente trabajo se propone que las bases moleculares de la vulnerabilidad neuronal selectiva estan relacionadas con las adaptaciones celulares al estres oxidativo. Material y metodos Con esta idea, se ha procedido a la seleccion de 5 regiones diferentes del sistema nervioso central de individuos sanos (n = 7) para: i) evaluar el perfil en acidos grasos de los lipidos de membrana mediante metodos cromatograficos; ii) determinar la susceptibilidad de membrana a la peroxidacion lipidica, y iii) reconocer mecanismos implicados en su regulacion. Resultados Los resultados muestran diferencias significativas interregionales en el perfil de acidos grasos, basicamente debidas al contenido de monoinsaturados y poliinsaturados con mas de 3 dobles enlaces; que dichos cambios, a su vez, inducen diferencias significativas en sus susceptibilidades a la peroxidacion, y que dichas diferencias se pueden adscribir a la actividad desaturasa. Conclusiones Asi pues, la aproximacion comparativa interregional parece confirmar la idea del grado de insaturacion de una membrana celular como caracteristica clave de la vulnerabilidad neuronal selectiva.

X-linked adrenoleukodystrophy is a neurometabolic disorder caused by inactivation of the peroxisomal ABCD1 transporter of very long-chain fatty acids. In mice, ABCD1 loss causes late onset axonal degeneration in the spinal cord in association with locomotor disability resembling the most common phenotype in patients, adrenomyeloneuropathy. Increasing evidence indicates that oxidative stress and bioenergetic failure play major roles in the pathogenesis of X-linked adrenoleukodystrophy. In this study, we aimed to evaluate whether mitochondrial biogenesis is affected in X-linked adrenoleukodystrophy. We demonstrated that Abcd1 null mice show reduced mitochondrial DNA concomitant with downregulation of mitochondrial biogenesis pathway driven by PGC-1α/PPARγ and reduced expression of mitochondrial proteins cytochrome c, NDUFB8 and VDAC. Moreover, we show that the oral administration of pioglitazone, an agonist of PPARγ, restored mitochondrial content and expression of master regulators of biogenesis, neutralized oxidative damage to proteins and DNA, and reversed bioenergetic failure in terms of ATP levels, NAD+/NADH ratios, pyruvate kinase and glutathione reductase activities. Most importantly, the treatment halted locomotor disability and axonal damage in X-linked adrenoleukodystrophy mice. These results lend support to the use of pioglitazone in clinical trials with patients with adrenomyeloneuropathy and reveal novel molecular mechanisms of action of pioglitazone in neurodegeneration. Future studies should address the effects of this anti-diabetic drug on other axonopathies in which oxidative stress and mitochondrial dysfunction are contributing factors. This work was supported by grants from the European Commission [FP7-241622], the European Leukodystrophy Association [ELA2009-036C5, ELA2008-040C4], the Spanish Institute for Health Carlos III [FIS PI11/01043], the Autonomous Government of Catalonia [2009SGR85 to A.P.], the Spanish Institute for Health Carlos III [Miguel Servet program CP11/ 00080 to S.F.], the COST action [BM0604 to A.P.]. S.F. was a fellow of the European Leukodystrophy Association [ELA 2010- 020F1]. L.M. is a fellow of the Spanish Ministry of Education [FPU program: AP2008-03728]. J.G. was a fellow of IDIBELL. The studies conducted at the Experimental Medicine Department were supported in part by R +D grants from the Spanish Ministry of Science and Innovation [BFU2009-11879/BFI], the Spanish Ministry of Health [PI081843], the Autonomous Government of Catalonia [2009SGR735], the ‘La Caixa’ Foundation and COST B35 Action of the European Union. The CIBER on Rare Diseases (CIBERER) and the CIBER on Neurodegenerative Diseases (CIBERNED) are initiatives of the ISCIII.

Membrane lipid composition is an important correlate of the rate of aging of animals. Dietary methionine restriction (MetR) increases lifespan in rodents. The underlying mechanisms have not been elucidated but could include changes in tissue lipidomes. In this work, we demonstrate that 80% MetR in mice induces marked changes in the brain, spinal cord, and liver lipidomes. Further, at least 50% of the lipids changed are common in the brain and spinal cord but not in the liver, suggesting a nervous system-specific lipidomic profile of MetR. The differentially expressed lipids includes (a) specific phospholipid species, which could reflect adaptive membrane responses, (b) sphingolipids, which could lead to changes in ceramide signaling pathways, and (c) the physiologically redox-relevant ubiquinone 9, indicating adaptations in phase II antioxidant response metabolism. In addition, specific oxidation products derived from cholesterol, phosphatidylcholine, and phosphatidylethanolamine were significantly decreased in the brain, spinal cord, and liver from MetR mice. These results demonstrate the importance of adaptive responses of membrane lipids leading to increased stress resistance as a major mechanistic contributor to the lowered rate of aging in MetR mice. © 2013 American Chemical Society.

Lipids played a determinant role in the evolution of the brain. It is postulated that the morphological and functional diversity among neural cells of the human central nervous system (CNS) is projected and achieved through the expression of particular lipid profiles. The present study was designed to evaluate the differential vulnerability to oxidative stress mediated by lipids through a cross-regional comparative approach. To this end, we compared 12 different regions of CNS of healthy adult subjects, and the fatty acid profile and vulnerability to lipid peroxidation, were determined by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS), respectively. In addition, different components involved in PUFA biosynthesis, as well as adaptive defense mechanisms against lipid peroxidation, were also measured by western blot and immunohistochemistry, respectively. We found that: i) four fatty acids (18.1n-9, 22:6n-3, 20:1n-9, and 18:0) are significant discriminators among CNS regions; ii) these differential fatty acid profiles generate a differential selective neural vulnerability (expressed by the peroxidizability index); iii) the cross-regional differences for the fatty acid profiles follow a caudal-cranial gradient which is directly related to changes in the biosynthesis pathways which can be ascribed to neuronal cells; and iv) the higher the peroxidizability index for a given human brain region, the lower concentration of the protein damage markers, likely supported by the presence of adaptive antioxidant mechanisms. In conclusion, our results suggest that there is a region-specific vulnerability to lipid peroxidation and offer evidence of neuronal mechanisms for polyunsaturated fatty acid biosynthesis in the human central nervous system.

Rapamycin consistently increases longevity in mice although the mechanism of action of this drug is unknown. In the present investigation we studied the effect of rapamycin on mitochondrial oxidative stress at the same dose that is known to increase longevity in mice (14 mg of rapamycin/kg of diet). Middle aged mice (16 months old) showed significant age-related increases in mitochondrial ROS production at complex I, accumulation of mtDNA fragments inside nuclear DNA, mitochondrial protein lipoxidation, and lipofuscin accumulation compared to young animals (4 months old) in the liver. After 7 weeks of dietary treatment all those increases were totally or partially (lipofuscin) abolished by rapamycin, middle aged rapamycin-treated animals showing similar levels in those parameters to young animals. The decrease in mitochondrial ROS production was due to qualitative instead of quantitative changes in complex I. The decrease in mitochondrial protein lipoxidation was not due to decreases in the amount of highly oxidizable unsaturated fatty acids. Rapamycin also decreased the amount of RAPTOR (of mTOR complex) and increased the amounts of the PGC1-α and ATG13 proteins. The results are consistent with the possibility that rapamycin increases longevity in mice at least in part by lowering mitochondrial ROS production and increasing autophagy, decreasing the derived final forms of damage accumulated with age which are responsible for increased longevity. The decrease in lipofuscin accumulation induced by rapamycin adds to previous information suggesting that the increase in longevity induced by this drug can be due to a decrease in the rate of aging. © 2016 Elsevier Inc. Sin financiación 3.340 JCR (2016) Q1, 12/49 Geriatrics and Gerontology UEM

Maillard reaction contributes to the chemical modification and cross-linking of proteins. This process plays a significant role in the aging process and determination of animal longevity. Oxidative conditions promote the Maillard reaction. Mitochondria are the primary site of oxidants due to the reactive molecular species production. Mitochondrial proteome cysteine residues are targets of oxidative attack due to their specific chemistry and localization. Their chemical, non-enzymatic modification leads to dysfunctional proteins, which entail cellular senescence and organismal aging. Previous studies have consistently shown that caloric and methionine restrictions, nutritional interventions that increase longevity, decrease the rate of mitochondrial oxidant production and the physiological steady-state levels of markers of oxidative damage to macromolecules. In this scenario, we have detected S-(carboxymethyl)-cysteine (CMC) as a new irreversible chemical modification in mitochondrial proteins. CMC content in mitochondrial proteins significantly correlated with that of the lysine-derived analog N e-(carboxymethyl)-lysine. The concentration of CMC is, however, one order of magnitude lower compared with CML likely due in part to the lower content of cysteine with respect to lysine of the mitochondrial proteome. CMC concentrations decreases in liver mitochondrial proteins of rats subjected to 8.5 and 25 % caloric restriction, as well as in 40 and 80 % methionine restriction. This is associated with a concomitant and significant increase in the protein content of sulfhydryl groups. Data presented here evidence that CMC, a marker of Cys-AGE formation, could be candidate as a biomarker of mitochondrial damage during aging.

Membrane unsaturation plays an important role in the aging process and the determination of inter-species animal longevity. Furthermore, the accumulation of oxidation-derived molecular damage to cellular components particularly in the nervous and immune systems over time leads to homeostasis loss, which highly influences age-related morbidity and mortality. In this context, it is of great interest to know and discern the degree of membrane unsaturation and the steady-state levels of oxidative damage in both physiological systems from long-lived subjects. In the present work, adult (28 ± 4 weeks), old (76 ± 4 weeks) and exceptionally old (128 ± 4 weeks) BALB/c female mice were used. Brain and spleen were analysed for membrane fatty acid composition and specific markers of protein oxidation, glycoxidation and lipoxidation damage, i.e. glutamic semialdehyde, aminoadipic semialdehyde, carboxyethyl-lysine, carboxymethyl-lysine and malondialdehyde-lysine, by gas chromatography-mass spectrometry. The results showed significantly lower peroxidizability index in brain and spleen from exceptionally old animals when compared to old specimens. The higher membrane resistance to lipid peroxidation and lower lipoxidation-derived molecular damage found in exceptionally old animals was associated with a significantly lower desaturase activity and peroxisomal β-oxidation. Protein oxidation markers in brain and spleen from adult and exceptionally old animals showed similar levels, which were higher in old mice. In addition, the higher levels of the glycoxidation-derived marker observed in exceptionally old animals, as well as in adult mice, could be considered as a good indicator of a better bioenergetic state of these animals when compared to the old group. In conclusion, low lipid oxidation susceptibility and maintenance of adult-like protein lipoxidative damage could be key mechanisms for longevity achievement.

Oxidative stress has been implicated in diabetes long-term complications. In this paper, we summarize the growing evidence suggesting that hyperglycemia-induced overproduction of superoxide by mitochondrial electron transport chain triggers a maladaptive response by affecting severalmetabolic and signaling pathways involved in the pathophysiology of cellular dysfunction and diabetic complications. In particular, it is our goal to describe physiological mechanisms underlying the mitochondrial free radical production and regulation to explain the oxidative stress derived from a high intracellular glucose concentration and the resulting maladaptive response that leads to a cellular dysfunction and pathological state. Finally, we outline potential therapies for diabetes focused to the prevention of mitochondrial oxidative damage. Investigations of the authors of this paper have been supported by Grants ref. BFI2003-01287, BFU2006-14495/BFI and BFU2009-11879/BFI; Reticef RD06/0013/0012, and 2005SGR00101, and 2009SGR735 from the Ministry of Science and Innovation, Ministry of Health, and the Autonomous Government of Catalonia, respectively.

Objective Axonal degeneration is a main contributor to disability in progressive neurodegenerative diseases in which oxidative stress is often identified as a pathogenic factor. We aim to demonstrate that antioxidants are able to improve axonal degeneration and locomotor deficits in a mouse model of X-adrenoleukodystrophy (X-ALD). Methods X-ALD is a lethal disease caused by loss of function of the ABCD1 peroxisomal transporter of very long chain fatty acids (VLCFA). The mouse model for X-ALD exhibits a late onset neurological phenotype with locomotor disability and axonal degeneration in spinal cord resembling the most common phenotype of the disease, adrenomyeloneuropathy (X-AMN). Recently, we identified oxidative damage as an early event in life, and the excess of VLCFA as a generator of radical oxygen species (ROS) and oxidative damage to proteins in X-ALD. Results Here, we prove the capability of the antioxidants N-acetyl-cysteine, α-lipoic acid, and α-tocopherol to scavenge VLCFA-dependent ROS generation in vitro. Furthermore, in a preclinical setting, the cocktail of the 3 compounds reversed: (1) oxidative stress and lesions to proteins, (2) immunohistological signs of axonal degeneration, and (3) locomotor impairment in bar cross and treadmill tests. Interpretation We have established a direct link between oxidative stress and axonal damage in a mouse model of neurodegenerative disease. This conceptual proof of oxidative stress as a major disease-driving factor in X-AMN warrants translation into clinical trials for X-AMN, and invites assessment of antioxidant strategies in axonopathies in which oxidative damage might be a contributing factor. Ann Neurol 2011

Mitochondria-related oxidative damage is a primary event in aging and age-related neurodegenerative disorders. Some dietary treatments, such as antioxidant supplementation or the enrichment of mitochondrial membranes with less oxidizable fatty acids, reduce lipid peroxidation and lengthen life span in rodents. This study compares life-long feeding on monounsaturated fatty acids (MUFAs), such as virgin olive oil, and n-6 polyunsaturated fatty acids, such as sunflower oil, with or without coenzyme Q10 supplementation, with respect to age-related molecular changes in rat brain mitochondria. The MUFA diet led to diminished age-related phenotypic changes, with lipoxidation-derived protein markers being higher among the older animals, whereas protein carbonyl compounds were lower. It is noteworthy that the MUFA diet prevented the age-related increase in levels of mitochondrial DNA deletions in the brain mitochondria from aged animals. The findings of this study suggest that age-related oxidative stress is related, at the mitochondrial level, to other age-related features such as mitochondrial electron transport and mtDNA alterations, and it can be modulated by selecting an appropriate dietary fat type and/or by suitable supplementation with low levels of the antioxidant/electron carrier molecule coenzyme Q.

Anabolic androgenic steroids are used in the sport context to enhance muscle mass and strength and to increase muscle fatigue resistance. Since muscle fatigue has been related to oxidative stress caused by an exercise-linked reactive oxygen species (ROS) production, we investigated the potential effects of a treatment with the anabolic androgenic steroid stanozolol against oxidative damage induced on rat skeletal muscle mitochondria by an acute bout of exhaustive exercise. Mitochondrial ROS generation with complex I- and complex II-linked substrates was increased in exercised control rats, whereas it remained unchanged in the steroid-treated animals. Stanozolol treatment markedly reduced the extent of exercise-induced oxidative damage to mitochondrial proteins, as indicated by the lower levels of the specific markers of protein oxidation, glycoxidation, and lipoxidation, and the preservation of the activity of the superoxide-sensitive enzyme aconitase. This effect was not due to an enhancement of antioxidant enzyme activities. Acute exercise provoked changes in mitochondrial membrane fatty acid composition characterized by an increased content in docosahexaenoic acid. In contrast, the postexercise mitochondrial fatty acid composition was not altered in stanozolol-treated rats. Our results suggest that stanozolol protects against acute exercise-induced oxidative stress by reducing mitochondrial ROS production, in association with a preservation of mitochondrial membrane properties.

The interruption of the β-adrenergic receptor signaling at the level of adenylyl cyclase (AC) by specifically knocking out (KO) the AC5 gene activates the RAF/MEK/ extracellular signal-regulated kinase (ERK) signaling pathway, delays bone and heart aging, and increases mean and maximum longevity in mice. However, the mechanisms involved in life extension in this animal model with increased longevity have not been clarified, although a decrease in oxidative stress has been proposed as mediator. Two traits link longevity and oxidative stress. Long-lived mammals and birds have a low rate of mitochondrial reactive oxygen species (mitROS) generation and a low degree of membrane fatty acid unsaturation, but these key factors have not been studied in AC5 KO mice. In the present investigation, male C57BL/6 mice were treated with the β-blocker atenolol in drinking water, and oxidative stress-related parameters were measured in the heart. Atenolol treatment did not change the rate of mitROS production and oxidative damage to mitDNA (8-oxo-7,8-dihydro-2'-deoxyguanosine [8-oxodG]), but strongly decreased the degree of fatty acid unsaturation and the peroxidizability index, mainly due to decreases in 22:6n-3 and 20:4n-6 and to increases in 18:1n-9, 16:1n-7 and 16:0 in the atenolol group. Protein oxidation and lipoxidation were lower in the atenolol group than in the controls. The mitochondrial complex I and IV content and the amount of p-ERK1/2 signaling proteins were significantly higher in the atenolol-treated than in the control animals. These results support the idea that the increased longevity of the AC5 KO mice can be due in part to an ERK signaling-mediated stress-resistance due to a decrease in fatty acid unsaturation, leading to lower lipid peroxidation and decreased lipoxidation-derived damage to cellular proteins.

Resumen Las proteinas mitocondriales pueden ser modificadas por reacciones de glicacion inducidas por compuestos dicarbonilo procedentes del metabolismo tales como el glioxal y el metilglioxal. Estas modificaciones provocan cambios estructurales y funcionales en las proteinas implicadas. La modificacion del proteoma mitocondrial por estos compuestos dicarbonilo puede inducir disfuncion mitocondrial y acentuar un estado de estres oxidativo. Asi, estas modificaciones quimicas podrian jugar un papel clave en el proceso fisiologico de envejecimiento y patologias asociadas a la edad, donde se han evidenciado tanto defectos de la actividad mitocondrial como incrementos de compuestos dicarbonilo. Identificar las proteinas mitocondriales especificamente modificadas, aseverar los cambios funcionales derivados y sus implicaciones constituyen lineas de investigacion que tendran su desarrollo en los proximos anos.

Mutations in mitochondrial oxidative phosphorylation complex I are associated with multiple pathologies, and complex I has been proposed as a crucial regulator of animal longevity. In yeast, the single-subunit NADH dehydrogenase Ndi1 serves as a non-proton-translocating alternative enzyme that replaces complex I, bringing about the reoxidation of intramitochondrial NADH. We have created transgenic strains of Drosophila that express yeast NDI1 ubiquitously. Mitochondrial extracts from NDI1 -expressing flies displayed a rotenone-insensitive NADH dehydrogenase activity, and functionality of the enzyme in vivo was confirmed by the rescue of lethality resulting from RNAi knockdown of complex I. NDI1 expression increased median, mean, and maximum lifespan independently of dietary restriction, and with no change in sirtuin activity. NDI1 expression mitigated the aging associated decline in respiratory capacity and the accompanying increase in mitochondrial reactive oxygen species production, and resulted in decreased accumulation of markers of oxidative damage in aged flies. Our results support a central role of mitochondrial oxidative phosphorylation complex I in influencing longevity via oxidative stress, independently of pathways connected to nutrition and growth signaling.

X-linked adrenoleukodystrophy (X-ALD) is a fatal, axonal demyelinating, neurometabolic disease. It results from the functional loss of a member of the peroxisomal ATP-binding cassette transporter subfamily D (ABCD1), which is involved in the metabolism of very long-chain fatty acids (VLCFA). Oxidative damage of proteins caused by excess of the hexacosanoic acid, the most prevalent VLCFA accumulating in X-ALD, is an early event in the neurodegenerative cascade. We demonstrate here that valproic acid (VPA), a widely used anti-epileptic drug with histone deacetylase inhibitor properties, induced the expression of the functionally overlapping ABCD2 peroxisomal transporter. VPA corrected the oxidative damage and decreased the levels of monounsaturated VLCFA (C26:1 n-9), but not saturated VLCFA. Overexpression of ABCD2 alone prevented oxidative lesions to proteins in a mouse model of X-ALD. A 6-month pilot trial of VPA in X-ALD patients resulted in reversion of the oxidative damage of proteins in peripheral blood mononuclear cells. Thus, we propose VPA as a promising novel therapeutic approach that warrants further clinical investigation in X-ALD. This work was supported by grants from the European Commission (LSHM-CT2004-502987 and FP7-241622), the European Leukodystrophy Association (ELA 2006-043I4), the Spanish Institute for Health Carlos III (FIS PI080991 and FIS PI051118) and the Autonomous Government of Catalonia (2009SGR85) to A.P. S.F. was a fellow of the European Leukodystrophy Association (ELA 2007-018F4). S.K. also received a grant from the European Leukodystrophy Association (ELA 2006-031I4). The work was developed under the COST action BM0604 (to A.P.). The CIBER de Enfermedades Raras is an initiative of the ISCIII. Work carried out at the Department of Experimental Medicine was supported in part by I + D grants from the Spanish Ministry of Science and Innovation (AGL2006-12433 and BFU2009-11879/BFI), the Spanish Ministry of Health (RD06/0013/0012 and PI081843), the Autonomous Government of Catalonia (2009SGR735), ‘La Caixa’ Foundation and COST B35 Action from the European Union. A.N. received a predoctoral fellowship from ‘La Caixa’ Foundation.

Methionine restriction without energy restriction increases, like caloric restriction, maximum longevity in rodents. Previous studies have shown that methionine restriction strongly decreases mitochondrial reactive oxygen species (ROS) production and oxidative damage to mitochondrial DNA, lowers membrane unsaturation, and decreases five different markers of protein oxidation in rat heart and liver mitochondria. It is unknown whether methionine supplementation in the diet can induce opposite changes, which is also interesting because excessive dietary methionine is hepatotoxic and induces cardiovascular alterations. Because the detailed mechanisms of methionine-related hepatotoxicity and cardiovascular toxicity are poorly understood and today many Western human populations consume levels of dietary protein (and thus, methionine) 2-3.3 fold higher than the average adult requirement, in the present experiment we analyze the effect of a methionine supplemented diet on mitochondrial ROS production and oxidative damage in the rat liver and heart mitochondria. In this investigation male Wistar rats were fed either a L-methionine-supplemented (2.5 g/100 g) diet without changing any other dietary components or a control (0.86 g/100 g) diet for 7 weeks. It was found that methionine supplementation increased mitochondrial ROS generation and percent free radical leak in rat liver mitochondria but not in rat heart. In agreement with these data oxidative damage to mitochondrial DNA increased only in rat liver, but no changes were observed in five different markers of protein oxidation in both organs. The content of mitochondrial respiratory chain complexes and AIF (apoptosis inducing factor) did not change after the dietary supplementation while fatty acid unsaturation decreased. Methionine, S-AdenosylMethionine and S-AdenosylHomocysteine concentration increased in both organs in the supplemented group. These results show that methionine supplementation in the diet specifically increases mitochondrial ROS production and mitochondrial DNA oxidative damage in rat liver mitochondria offering a plausible mechanism for its hepatotoxicity.

Previous studies have shown that the decrease in mitochondrial reactive oxygen species (mitROS) generation and oxidative damage to mitochondrial DNA (mtDNA) that occurs during life extending dietary restriction also occurs during protein or methionine restriction, whereas it does not take place during carbohydrate or lipid restriction. In order to study the possible effects of other amino acids, in this investigation all the dietary amino acids, except methionine, were restricted by 40% in male Wistar rats (RESTAAS group). After 6-7 weeks, experimental parameters were measured in the liver. Amino acid restriction did not change the levels of the methionine metabolites S-adenosylmethionine and S-adenosylhomocysteine, mitochondrial oxygen consumption and ROS generation, oxidative damage to mtDNA, amounts of the respiratory complexes I-IV, and the mitochondrial biogenesis factors PGC-1alpha and NRF-2. On the other hand, adenylate energy charge, mitochondrial protein oxidation, lipooxidation and glycooxidation, the degree of mitochondrial fatty acid unsaturation, and the amount of the apoptosis inducing factor (AIF) were decreased in the RESTAAS group. Amino acid restriction also increased SIRT1 protein. These results, together with previous ones, strongly suggest that the decrease in mitROS generation and oxidative damage to mtDNA that occurs during dietary restriction is due to restriction of a single aminoacid: methionine. They also show for the first time that restriction of dietary amino acids different from methionine decreases mitochondrial protein oxidative modification and AIF, and increases SIRT1, in rat liver.

Aging plays a central role in the occurrence of neurodegenerative diseases. Caloric restriction (CR) mitigates oxidative stress by decreasing the rate of generation of endogenous damage, a mechanism that can contribute to the slowing of the aging rate induced by this intervention. Various reports have recently linked methionine to aging, and methionine restriction (MetR) without energy restriction also increases life span. We have thus hypothesized that MetR can be responsible, at least in part, for the decrease in endogenous oxidative damage in CR. In this investigation we subjected male rats to exactly the same dietary protocol of MetR that is known to increase their life span. We have found that MetR: (1) decreases the mitochondrial complex I content and activity, as well as complex III content, while the complex II and IV, the mitochondrial flavoprotein apoptosis-inducing factor (AIF) and ATP content are unchanged; (2) increases the mitochondrial biogenesis factor PGC-1alpha; (3) increases the resistance of brain to metabolic and oxidative stress by increasing mitochondrial uncoupling protein 4 uncoupling protein 4 (UCP4); and (4) decreases mitochondrial oxidative DNA damage and all five different markers of protein oxidation measured and lowers membrane unsaturation in rat brain. No changes were detected for protein amino acid composition. These beneficial MetR-induced changes likely derived from metabolic reprogramming at the cellular and tissue level can play a key role in the protection against aging-associated neurodegenerative disorders.

Previous studies have consistently shown that 40% caloric restriction (CR) decreases the rate of mitochondrial ROS production and steady-state levels of markers of oxidative damage to macromolecules including mitochondrial DNA. However, few investigations have studied whether these changes also occur in lower CR regimes. This is of potential interest since moderate levels of dietary restriction are more practicable for humans. In this investigation male Wistar rats were subjected to 8.5% and 25% caloric restriction. Neither 8.5% nor 25% CR changed mitochondrial ROS production, oxygen consumption or mtDNA oxidative damage in rat liver mitochondria. However, both 8.5% and 25% CR significantly decreased the five different markers of protein oxidation, glycoxidation and lipoxidation measured, aminoadipic and glutamic semialdehyde, carboxyethyl-lysine, carboxymethyl-lysine, and malondialdehyde-lysine. The fatty acid composition of liver mitochondria was also affected and led to a moderate decrease in the degree of membrane unsaturation in both 8.5% and 25% CR. While 8.5% CR only affected complex I concentration (which was decreased), 25% CR decreased complexes I and IV and increased complexes II and III of the respiratory chain. Apoptosis-inducing factor (AIF) significantly decreased in 25% CR but not in 8.5% CR. The results show that moderate levels of caloric restriction can have beneficial effects including decreases in oxidative protein modification and a lower sensitivity of membranes to lipid peroxidation, in association with a reprogramming of the respiratory chain complexes and AIF content.

Lipids stimulated and favored the evolution of the brain. Adult human brain contains a large amount of lipids, and the largest diversity of lipid classes and lipid molecular species. Lipidomics is defined as "the full characterization of lipid molecular species and of their biological roles with respect to expression of proteins involved in lipid metabolism and function, including gene regulation." Therefore, the study of brain lipidomics can help to unravel the diversity and to disclose the specificity of these lipid traits and its alterations in neural (neurons and glial) cells, groups of neural cells, brain, and fluids such as cerebrospinal fluid and plasma, thus helping to uncover potential biomarkers of human brain aging and Alzheimer disease. This review will discuss the lipid composition of the adult human brain. We first consider a brief approach to lipid definition, classification, and tools for analysis from the new point of view that has emerged with lipidomics, and then turn to the lipid profiles in human brain and how lipids affect brain function. Finally, we focus on the current status of lipidomics findings in human brain aging and Alzheimer's disease pathology. Neurolipidomics will increase knowledge about physiological and pathological functions of brain cells and will place the concept of selective neuronal vulnerability in a lipid context.

Plasma lipidomic profile is species specific and an optimized feature associated with animal longevity. In the present work, the use of mass spectrometry technologies allowed us to determine the plasma lipidomic profile and the fatty acid pattern of healthy humans with exceptional longevity. Here, we show that it is possible to define a lipidomic signature only using 20 lipid species to discriminate adult, aged and centenarian subjects obtaining an almost perfect accuracy (90%-100%). Furthermore, we propose specific lipid species belonging to ceramides, widely involved in cell-stress response, as biomarkers of extreme human longevity. In addition, we also show that extreme longevity presents a fatty acid profile resistant to lipid peroxidation. Our findings indicate that lipidomic signature is an optimized feature associated with extreme human longevity. Further, specific lipid molecular species and lipid unsaturation arose as potential biomarkers of longevity.

The evolution of lifespan is a central question in evolutionary biology, begging the question why there is so large variation among taxa. Specifically, a central quest is to unravel proximate causes of ageing. Here, we show that the degree of unsaturation of liver fatty acids predicts maximum lifespan in 107 bird species. In these birds, the degree of fatty acid unsaturation is positively related to maximum lifespan across species. This is due to a positive effect of monounsaturated fatty acid content, while polyunsaturated fatty acid content negatively correlates with maximum lifespan. Furthermore, fatty acid chain length unsuspectedly increases with maximum lifespan independently of degree of unsaturation. These findings tune theories on the proximate causes of ageing while providing evidence that the evolution of lifespan in birds occurs in association with fatty acid profiles. This suggests that studies of proximate and ultimate questions may facilitate our understanding of these central evolutionary questions.

It has been described that dietary cysteine reverses many of the beneficial changes induced by methionine restriction in aging rodents. In this investigation male Wistar rats were subjected to diets low in methionine, supplemented with cysteine, or simultaneously low in methionine and supplemented with cysteine. The results obtained in liver showed that cysteine supplementation reverses the decrease in mitochondrial ROS generation induced by methionine restriction at complex I. Methionine restriction also decreased various markers of oxidative and non-oxidative stress on mitochondrial proteins which were not reversed by cysteine. Instead, cysteine supplementation also lowered protein damage in association with decreases in mTOR activation. The results of the present study add the decrease in mitochondrial ROS production to the various beneficial changes induced by methionine restriction that are reversed by cysteine dietary supplementation.

Lipids stimulated and favored the evolution of the brain. Adult human brain contains a large amount of lipids, and the largest diversity of lipid classes and lipid molecular species. Lipidomics is defined as "the full characterization of lipid molecular species and of their biological roles with respect to expression of proteins involved in lipid metabolism and function, including gene regulation." Therefore, the study of brain lipidomics can help to unravel the diversity and to disclose the specificity of these lipid traits and its alterations in neural (neurons and glial) cells, groups of neural cells, brain, and fluids such as cerebrospinal fluid and plasma, thus helping to uncover potential biomarkers of human brain aging and Alzheimer disease. This review will discuss the lipid composition of the adult human brain. We first consider a brief approach to lipid definition, classification, and tools for analysis from the new point of view that has emerged with lipidomics, and then turn to the lipid profiles in human brain and how lipids affect brain function. Finally, we focus on the current status of lipidomics findings in human brain aging and Alzheimer's disease pathology. Neurolipidomics will increase knowledge about physiological and pathological functions of brain cells and will place the concept of selective neuronal vulnerability in a lipid context.

Aging and age-related diseases are one of the most important health issues that the world will confront during the 21st century. Only by understanding the proximal causes will we be able to find treatments to reduce or delay the onset of degenerative diseases associated with aging. Currently, the prevalent paradigm in the field is the accumulation of damage. However, a new theory that proposes an alternative explanation is gaining momentum. The hyperfunction theory proposes that aging is not a consequence of a wear and tear process, but a result of the continuation of developmental programs during adulthood. Here we use Drosophila melanogaster, where evidence supporting both paradigms has been reported, to identify which parameters that have been previously related with lifespan best predict the rate of aging in wild type flies cultured at different temperatures. We find that mitochondrial function and mitochondrial reactive oxygen species (mtROS) generation correlates with metabolic rate, but not with the rate of aging. Importantly, we find that activation of nutrient sensing pathways (i.e. insulin-PI3K/Target of rapamycin (Tor) pathway) correlates with lifespan, but not with metabolic rate. Our results, dissociate metabolic rate and lifespan in wild type flies and instead link nutrient sensing signaling with longevity as predicted by the hyperfunction theory. This study was supported by the European Research Council (ERC Starting Grant to A.S.), the Academy of Finland (Research Academy Fellowship to A.S), the Spanish Ministry of Economy and Competitiveness (BFU2009-11879/BFI; RD12/0043/0018 and PI1400328 to R.P.), and the Autonomous Government of Catalonia (2014SGR168 to R.P).