Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 83
Filtrar
1.
J Epidemiol ; 2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33642515

RESUMO

AIMS: As the proportion of visceral (VAT) to subcutaneous adipose tissue (SAT) may contribute to type 2 diabetes (T2D) development, we examined this relation in a cross-sectional design within the Multiethnic Cohort that includes Japanese Americans known to have high VAT. The aim was to understand how ectopic fat accumulation differs by glycemic status across ethnic groups with disparate rates of obesity, T2D, and propensity to accumulate VAT. METHODS: In 2013-16, 1,746 participants aged 69.2 (2.7) years from five ethnic groups completed questionnaires, blood collections, and whole-body DXA and abdominal MRI scans. Participants with self-reported T2D and/or medication were classified as T2D, those with fasting glucose >125 and 100-125 mg/dL as undiagnosed cases (UT2D) and prediabetes (PT2D), respectively. Using linear regression, we estimated adjusted means of adiposity measures by T2D status. RESULTS: Overall, 315 (18%) participants were classified as T2D, 158 (9%) as UT2D, 518 (30%) as PT2D, and 755 (43%) as normoglycemic (NG) with significant ethnic differences (p<0.0001). In fully adjusted models, VAT, VAT/SAT, and percent liver fat increased significantly from NG, PT2D, UT2D, to T2D (p<0.001). Across ethnic groups, the VAT/SAT ratio was lowest for NG participants and highest for T2D cases. Positive trends were observed in all groups except African Americans, with highest VAT/SAT in Japanese Americans. CONCLUSIONS: These findings indicate that VAT plays an important role in T2D etiology, in particular among Japanese Americans with high levels of ectopic adipose tissue, which drives the development of T2D to a greater degree than in other ethnic groups.

2.
Brain Res ; 1747: 147030, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32745658

RESUMO

The APOE Ɛ4 genotype is the most prevalent genetic risk for Alzheimer's disease (AD). Women carriers of Ɛ4 have higher risk for an early onset of AD than men. Human imaging studies suggest apolipoprotein Ɛ4 may affect brain structures associated with cognitive decline in AD many years before disease onset. It was hypothesized that female APOE Ɛ4 carriers would present with decreased cognitive function and neuroradiological evidence of early changes in brain structure and function as compared to male carriers. Six-month old wild-type (WT) and human APOE Ɛ4 knock-in (TGRA8960), male and female Sprague Dawley rats were studied for changes in brain structure using voxel-based morphometry, alteration in white and gray matter microarchitecture using diffusion weighted imaging with indices of anisotropy, and functional coupling using resting state BOLD functional connectivity. Images from each modality were registered to, and analyzed, using a 3D MRI rat atlas providing site-specific data on over 168 different brain areas. Quantitative volumetric analysis revealed areas involved in memory and arousal were significantly different between Ɛ4 and wild-type (WT) females, with few differences between male genotypes. Diffusion weighted imaging showed few differences between WT and Ɛ4 females, while male genotypes showed significant different measures in fractional anisotropy and apparent diffusion coefficient. Resting state functional connectivity showed Ɛ4 females had greater connectivity between areas involved in cognition, emotion, and arousal compared to WT females, with male Ɛ4 showing few differences from controls. Interestingly, male Ɛ4 showed increased anxiety and decreased performance in spatial and episodic memory tasks compared to WT males, with female genotypes showing little difference across behavioral tests. The sex differences in behavior and diffusion weighted imaging suggest male carriers of the Ɛ4 allele may be more vulnerable to cognitive and emotional complications compared to female carriers early in life. Conversely, the data may also suggest that female carriers are more resilient to cognitive/emotional problems at this stage of life perhaps due to altered brain volumes and enhanced connectivity.

3.
Hepatol Commun ; 4(8): 1112-1123, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32766472

RESUMO

The global rise in fatty liver is a major public health problem. Thus, it is critical to identify both global and population-specific genetic variants associated with liver fat. We conducted a genome-wide association study (GWAS) of percent liver fat and nonalcoholic fatty liver disease (NAFLD) assessed by magnetic resonance imaging in 1,709 participants from the population-based Multiethnic Cohort Adiposity Phenotype Study. Our participants comprised older adults of five U.S. racial/ethnic groups: African Americans (n = 277), Japanese Americans (n = 424), Latinos (n = 348), Native Hawaiians (n = 274), and European Americans (n = 386). The established missense risk variant rs738409 located in patatin-like phospholipase domain containing 3 (PNPLA3) at 22q13 was confirmed to be associated with percent liver fat (P = 3.52 × 10-15) but more strongly in women than men (P heterogeneity = 0.002). Its frequency correlated with the prevalence of NAFLD across the five ethnic/racial groups. Rs738409 was also associated with homeostasis model assessment of insulin resistance (HOMA-IR) (beta = 0.028; P = 0.009) and circulating levels of insulin (beta = 0.022; P = 0.020) and alanine aminotransferase (beta = 0.016; P = 0.030). A novel association of percent liver fat with rs77249491 (located at 6q13 between limb region 1 domain containing 1 [LMBRD1] and collagen type XIX alpha 1 chain [COL19A1] (P = 1.42 × 10-8) was also observed. Rs7724941 was associated with HOMA-IR (beta = 0.12; P = 0.0005), insulin (beta = 0.11; P = 0.0003), triglycerides (beta = 0.059; P = 0.01), high-density lipoprotein (beta = -0.046; P = 0.04), and sex hormone binding globulin (beta = -0.084; P = 0.0012). This variant was present in Japanese Americans (minor allele frequency [MAF], 8%) and Native Hawaiians (MAF, 2%). Conclusion: We replicated the PNPLA3 rs738409 association in a multiethnic population and identified a novel liver fat risk variant in Japanese Americans and Native Hawaiians. GWASes of percent liver fat in East Asian and Oceanic populations are needed to replicate the rs77249491 association.

4.
Cancer Epidemiol Biomarkers Prev ; 29(5): 966-973, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32132150

RESUMO

BACKGROUND: Visceral adipose tissue (VAT) may play a greater role than subcutaneous fat in increasing cancer risk but is poorly estimated in epidemiologic studies. METHODS: We developed a VAT prediction score by regression equations averaged across 100 least absolute shrinkage and selection operator models in a cross-sectional study of 1,801 older adults in the Multiethnic Cohort (MEC). The score was then used as proxy for VAT in case-control studies of postmenopausal breast (950 case-control pairs) and colorectal (831 case-control pairs) cancer in an independent sample in MEC. Abdominal MRI-derived VAT; circulating biomarkers of metabolic, hormonal, and inflammation dysfunctions; and ORs for incident cancer adjusted for BMI and other risk factors were assessed. RESULTS: The final score, composed of nine biomarkers, BMI, and height, explained 11% and 15% more of the variance in VAT than BMI alone in men and women, respectively. The area under the receiver operator curve for VAT >150 cm2 was 0.90 in men and 0.86 in women. The VAT score was associated with risk of breast cancer [OR (95% confidence interval [CI]) by increasing tertiles: 1.00, 1.09 (0.86-1.39), 1.48 (1.16-1.89); P trend = 0.002] but not with colorectal cancer (P = 0.84), although an association [1.00, 0.98 (0.68-1.39), 1.24 (0.88-1.76); P trend = 0.08] was suggested for this cancer after excluding cases that occurred within 7 years of blood draw (P heterogeneity = 0.06). CONCLUSIONS: The VAT score predicted risks of postmenopausal breast cancer and can be used for risk assessment in diverse populations. IMPACT: These findings provide specific evidence for a role of VAT in breast cancer.

5.
Mass Spectrom Rev ; 39(1-2): 35-54, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-30024655

RESUMO

This review discusses the integration of liquid chromatography (LC), mass spectrometry (MS), and nuclear magnetic resonance (NMR) in the comprehensive analysis of small molecules from complex matrices. We first discuss the steps taken toward making the three technologies compatible, so as to create an efficient analytical platform. The development of online LC-MS-NMR, highlighted by successful applications in the profiling of highly concentrated analytes (LODs 10 µg) is discussed next. This is followed by a detailed overview of the alternative approaches that have been developed to overcome the challenges associated with online LC-MS-NMR that primarily stem from the inherently low sensitivity of NMR. These alternative approaches include the use of stop-flow LC-MS-NMR, loop collection of LC peaks, LC-MS-SPE-NMR, and offline NMR. The potential and limitations of all these approaches is discussed in the context of applications in various fields, including metabolomics and natural product discovery.

6.
Sci Rep ; 9(1): 16681, 2019 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-31723161

RESUMO

We explored the predictive value of a neurobehavioral performance assessment under rested baseline conditions (evaluated at 8 hours awake following 8 hours of sleep) on neurobehavioral response to moderate sleep loss (evaluated at 20 hours awake two days later) in 151 healthy young participants (18-30 years). We defined each participant's response-to-sleep-loss phenotype based on the number of attentional failures on a 10-min visual psychomotor vigilance task taken at 20 hours awake (resilient: less than 6 attentional failures, n = 26 participants; non-resilient: 6 or more attentional failures, n = 125 participants). We observed that 97% of rested participants with 2 or more attentional failures (n = 73 of 151) and 100% of rested participants with 3 or more attentional failures (n = 57 of 151) were non-resilient after moderate sleep loss. Our approach can accurately identify a significant proportion of individuals who are at high risk for neurobehavioral performance impairment from staying up late with a single neurobehavioral performance assessment conducted during rested conditions. Additional methods are needed to predict the future performance of individuals who are not identified as high risk during baseline.


Assuntos
Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Descanso/fisiologia , Privação do Sono/fisiopatologia , Sono/fisiologia , Vigília/fisiologia , Adolescente , Adulto , Atenção , Ritmo Circadiano , Cognição , Feminino , Humanos , Masculino , Estudos Prospectivos , Adulto Jovem
7.
Sci Rep ; 9(1): 12102, 2019 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-31431644

RESUMO

There are strong individual differences in performance during sleep deprivation. We assessed whether baseline features of Psychomotor Vigilance Test (PVT) performance can be used for classifying participants' relative attentional vulnerability to total sleep deprivation. In a laboratory, healthy adults (n = 160, aged 18-30 years) completed a 10-min PVT every 2 h while being kept awake for ≥24 hours. Participants were categorized as vulnerable (n = 40), intermediate (n = 80), or resilient (n = 40) based on their number of PVT lapses during one night of sleep deprivation. For each baseline PVT (taken 4-14 h after wake-up time), a linear discriminant model with wrapper-based feature selection was used to classify participants' vulnerability to subsequent sleep deprivation. Across models, classification accuracy was about 70% (range 65-76%) using stratified 5-fold cross validation. The models provided about 78% sensitivity and 86% specificity for classifying resilient participants, and about 70% sensitivity and 89% specificity for classifying vulnerable participants. These results suggest features derived from a single 10-min PVT at baseline can provide substantial, but incomplete information about a person's relative attentional vulnerability to total sleep deprivation. In the long term, modeling approaches that incorporate baseline performance characteristics can potentially improve personalized predictions of attentional performance when sleep deprivation cannot be avoided.


Assuntos
Atenção/fisiologia , Desempenho Psicomotor , Privação do Sono/fisiopatologia , Vigília/fisiologia , Adolescente , Adulto , Nível de Alerta/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Individualidade , Modelos Lineares , Masculino , Tempo de Reação/fisiologia , Adulto Jovem
8.
Am J Epidemiol ; 188(6): 991-1012, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31155658

RESUMO

The Consortium of Metabolomics Studies (COMETS) was established in 2014 to facilitate large-scale collaborative research on the human metabolome and its relationship with disease etiology, diagnosis, and prognosis. COMETS comprises 47 cohorts from Asia, Europe, North America, and South America that together include more than 136,000 participants with blood metabolomics data on samples collected from 1985 to 2017. Metabolomics data were provided by 17 different platforms, with the most frequently used labs being Metabolon, Inc. (14 cohorts), the Broad Institute (15 cohorts), and Nightingale Health (11 cohorts). Participants have been followed for a median of 23 years for health outcomes including death, cancer, cardiovascular disease, diabetes, and others; many of the studies are ongoing. Available exposure-related data include common clinical measurements and behavioral factors, as well as genome-wide genotype data. Two feasibility studies were conducted to evaluate the comparability of metabolomics platforms used by COMETS cohorts. The first study showed that the overlap between any 2 different laboratories ranged from 6 to 121 metabolites at 5 leading laboratories. The second study showed that the median Spearman correlation comparing 111 overlapping metabolites captured by Metabolon and the Broad Institute was 0.79 (interquartile range, 0.56-0.89).


Assuntos
Epidemiologia/organização & administração , Saúde Global , Metabolômica/organização & administração , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Índice de Massa Corporal , Criança , Métodos Epidemiológicos , Feminino , Comportamentos Relacionados com a Saúde , Testes Hematológicos , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores Socioeconômicos , Adulto Jovem
9.
Oper Neurosurg (Hagerstown) ; 16(5): 607-613, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30169686

RESUMO

BACKGROUND: The posterior cervical keyhole (KH) laminoforaminotomy has been described to involve the lateral portion of cervical laminae of the upper vertebra alone (small KH) or of both upper and lower vertebrae (large KH). OBJECTIVE: To microscopically compare the two keyhole techniques in terms of their ability to expose the corresponding cervical roots. METHODS: Ten cadaveric specimens were operated bilaterally from C3-4 to C6-7 level to expose a total of 80 nerve roots. The large KH was applied to the left side, the small KH to the right side. The maximal length of exposed nerve roots was measured under microscope. The virtual optimal KH surface area was determined using digital software. Each root was inspected for exposure of its root and axilla. RESULTS: The maximal exposed nerve root length on the large KH side was significantly larger than on the small KH side at C3-4, C5-6, and C6-7 levels (P = .031, P = .002, P = .003). No significance was reported for C4-5 (P = .06). We could expose right axillae in (3/40) and left axillae in (33/40; P < .001). Optimal keyhole surface areas were 37.9, 38.2, 38.7, and 46.2 mm2 in craniocaudal order. CONCLUSION: Large KH defects involving both upper and lower laminae and facets can expose the roots to greater extent than small KH defects at C3-4, C5-6, and C6-7 levels. Large KH defects may allow better exposure of nerve roots axillae than small KH defects.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Foraminotomia/métodos , Laminectomia/métodos , Raízes Nervosas Espinhais/diagnóstico por imagem , Raízes Nervosas Espinhais/cirurgia , Cadáver , Vértebras Cervicais/patologia , Humanos , Raízes Nervosas Espinhais/patologia
10.
Gastroenterology ; 156(4): 966-975.e10, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30445012

RESUMO

BACKGROUND & AIMS: We compared fat storage in the abdominal region among individuals from 5 different ethnic-racial groups to determine whether fat storage is associated with disparities observed in metabolic syndrome and other obesity-associated diseases. METHODS: We collected data from 1794 participants in the Multiethnic Cohort Study (60-77 years old; of African, European [white], Japanese, Latino, or Native Hawaiian ancestry) with body mass index values of 17.1-46.2 kg/m2. From May 2013 through April 2016, participants visited the study clinic to undergo body measurements, an interview, and a blood collection. Participants were evaluated by dual-energy x-ray absorptiometry and abdominal magnetic resonance imaging. Among ethnic groups, we compared adiposity of the trunk, intra-abdominal visceral cavity, and liver, adjusting for total fat mass; we evaluated the association of adult weight change with abdominal adiposity; and we examined the prevalence of metabolic syndrome mediated by abdominal adiposity. RESULTS: Relative amounts of trunk, visceral, and liver fat varied significantly with ethnicity-they were highest in Japanese Americans, lowest in African Americans, and intermediate in the other groups. Compared with African Americans, the mean visceral fat area was 45% and 73% greater in Japanese American men and women, respectively, and the mean measurements of liver fat were 61% and 122% greater in Japanese American men and women. The visceral and hepatic adiposity associated with weight gain since participants were 21 years old varied in a similar pattern among ethnic-racial groups. In the mediation analysis, visceral and liver fat jointly accounted for a statistically significant fraction of the difference in metabolic syndrome prevalence, compared with white persons, for African Americans, Japanese Americans, and Native Hawaiian women, independently of total fat mass. CONCLUSIONS: In an analysis of data from the participants in the Multiethnic Cohort Study, we found extensive differences among ethnic-racial groups in the propensity to store fat intra-abdominally. This observation should be considered by clinicians in the prevention and early detection of metabolic disorders.


Assuntos
Adiposidade , Grupos Étnicos/estatística & dados numéricos , Gordura Intra-Abdominal , Síndrome Metabólica/etnologia , Absorciometria de Fóton , Afro-Americanos/estatística & dados numéricos , Idoso , Americanos Asiáticos/estatística & dados numéricos , Composição Corporal , Grupo com Ancestrais do Continente Europeu/estatística & dados numéricos , Feminino , Hawaii/etnologia , Hispano-Americanos/estatística & dados numéricos , Humanos , Gordura Intra-Abdominal/diagnóstico por imagem , Japão/etnologia , Fígado/diagnóstico por imagem , Imagem por Ressonância Magnética , Masculino , Grupo com Ancestrais Oceânicos/estatística & dados numéricos , Prevalência , Tronco/diagnóstico por imagem , Estados Unidos/epidemiologia , Ganho de Peso
11.
Proc Natl Acad Sci U S A ; 116(2): 650-659, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30584104

RESUMO

Neuritic retraction in the absence of overt neuronal death is a shared feature of normal aging and neurodegenerative disorders, but the intracellular mechanisms modulating this process are not understood. We propose that cumulative distal mitochondrial protein damage results in impaired protein import, leading to mitochondrial dysfunction and focal activation of the canonical apoptosis pathway in neurites. This is a controlled process that may not lead to neuronal death and, thus, we term this phenomenon "neuritosis." Consistent with our hypothesis, we show that in primary cerebrocortical neurons, mitochondrial distance from the soma correlates with increased mitochondrial protein damage, PINK1 accumulation, reactive oxygen species production, and decreased mitochondrial membrane potential and depolarization threshold. Furthermore, we demonstrate that the distance-dependent mitochondrial membrane potential gradient exists in vivo in mice. We demonstrate that impaired distal mitochondria have a lower threshold for focal/nonlethal neuritic caspase-3 activation in normal neurons that is exacerbated in aging, stress, and neurodegenerative conditions, thus delineating a fundamental mechanistic underpinning for synaptic vulnerability.


Assuntos
Apoptose , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Neuritos/metabolismo , Doenças Neurodegenerativas/metabolismo , Animais , Caspase 3/genética , Caspase 3/metabolismo , Camundongos , Camundongos Transgênicos , Mitocôndrias/genética , Mitocôndrias/patologia , Neuritos/patologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo
12.
JCI Insight ; 3(21)2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30385734

RESUMO

Hypertriglyceridemia is an independent risk factor for cardiovascular disease. Dietary interventions based on protein restriction (PR) reduce circulating triglycerides (TGs), but underlying mechanisms and clinical relevance remain unclear. Here, we show that 1 week of a protein-free diet without enforced calorie restriction significantly lowered circulating TGs in both lean and diet-induced obese mice. Mechanistically, the TG-lowering effect of PR was due, in part, to changes in very low-density lipoprotein (VLDL) metabolism both in liver and peripheral tissues. In the periphery, PR stimulated VLDL-TG consumption by increasing VLDL-bound APOA5 expression and promoting VLDL-TG hydrolysis and clearance from circulation. The PR-mediated increase in Apoa5 expression was controlled by the transcription factor CREBH, which coordinately regulated hepatic expression of fatty acid oxidation-related genes, including Fgf21 and Ppara. The CREBH-APOA5 axis activation upon PR was intact in mice lacking the GCN2-dependent amino acid-sensing arm of the integrated stress response. However, constitutive hepatic activation of the amino acid-responsive kinase mTORC1 compromised CREBH activation, leading to blunted APOA5 expression and PR-recalcitrant hypertriglyceridemia. PR also contributed to hypotriglyceridemia by reducing the rate of VLDL-TG secretion, independently of activation of the CREBH-APOA5 axis. Finally, a randomized controlled clinical trial revealed that 4-6 weeks of reduced protein intake (7%-9% of calories) decreased VLDL particle number, increased VLDL-bound APOA5 expression, and lowered plasma TGs, consistent with mechanistic conservation of PR-mediated hypotriglyceridemia in humans with translational potential as a nutraceutical intervention for dyslipidemia.


Assuntos
Dieta com Restrição de Proteínas/efeitos adversos , Lipoproteínas VLDL/sangue , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Triglicerídeos/sangue , Animais , Apolipoproteína A-V , Apolipoproteínas/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , Dieta com Restrição de Proteínas/métodos , Feminino , Humanos , Hidrólise , Hipertrigliceridemia/complicações , Hipertrigliceridemia/epidemiologia , Metabolismo dos Lipídeos , Lipoproteínas VLDL/metabolismo , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Proteínas Serina-Treonina Quinases/deficiência , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Triglicerídeos/metabolismo
13.
Anal Chem ; 90(22): 13523-13532, 2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30265528

RESUMO

Lipidomics requires the accurate annotation of lipids in complex samples to enable determination of their biological relevance. We demonstrate that unintentional in-source fragmentation (ISF, common in lipidomics) generates ions that have identical masses to other lipids. Lysophosphatidylcholines (LPC), for example, generate in-source fragments with the same mass as free fatty acids and lysophosphatidylethanolamines (LPE). The misannotation of in-source fragments as true lipids is particularly insidious in complex matrixes since most masses are initially unannotated and comprehensive lipid standards are unavailable. Indeed, we show such LPE/LPC misannotations are incorporated in the data submitted to the National Institute of Standards and Technology (NIST) interlaboratory comparison exercise. Computer simulations exhaustively identified potential misannotations. The selection of in-source fragments of highly abundant lipids as features, instead of the correct recognition of trace lipids, can potentially lead to (i) missing the biologically relevant lipids (i.e., a false negative) and/or (ii) incorrect assignation of a phenotype to an incorrect lipid (i.e., false positive). When ISF is not eliminated in the negative ion mode, ∼40% of the 100 most abundant masses corresponding to unique phospholipids measured in plasma were artifacts from ISF. We show that chromatographic separation and ion intensity considerations assist in distinguishing precursor ions from in-source fragments, suggesting ISF may be especially problematic when complex samples are analyzed via shotgun lipidomics. We also conduct a systematic evaluation of electrospray ionization (ESI) source parameters on an Exactive equipped with a heated electrospray ionization (HESI-II) source with the objective of obtaining uniformly appropriate source conditions for a wide range of lipids, while, at the same time, reducing in-source fragmentation.


Assuntos
Fosfolipídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Simulação por Computador
14.
Proc Natl Acad Sci U S A ; 114(30): 7981-7986, 2017 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-28630339

RESUMO

Brown adipose tissue (BAT) mitochondria exhibit high oxidative capacity and abundant expression of both electron transport chain components and uncoupling protein 1 (UCP1). UCP1 dissipates the mitochondrial proton motive force (Δp) generated by the respiratory chain and increases thermogenesis. Here we find that in mice genetically lacking UCP1, cold-induced activation of metabolism triggers innate immune signaling and markers of cell death in BAT. Moreover, global proteomic analysis reveals that this cascade induced by UCP1 deletion is associated with a dramatic reduction in electron transport chain abundance. UCP1-deficient BAT mitochondria exhibit reduced mitochondrial calcium buffering capacity and are highly sensitive to mitochondrial permeability transition induced by reactive oxygen species (ROS) and calcium overload. This dysfunction depends on ROS production by reverse electron transport through mitochondrial complex I, and can be rescued by inhibition of electron transfer through complex I or pharmacologic depletion of ROS levels. Our findings indicate that the interscapular BAT of Ucp1 knockout mice exhibits mitochondrial disruptions that extend well beyond the deletion of UCP1 itself. This finding should be carefully considered when using this mouse model to examine the role of UCP1 in physiology.


Assuntos
Aclimatação/fisiologia , Tecido Adiposo Marrom/metabolismo , Temperatura Baixa , Transporte de Elétrons , Proteína Desacopladora 1/deficiência , Animais , Cálcio/metabolismo , Feminino , Masculino , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Espécies Reativas de Oxigênio/metabolismo , Proteína Desacopladora 1/genética
15.
Brain Inj ; 31(10): 1376-1381, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28627942

RESUMO

PRIMARY OBJECTIVE: There is a need to understand pathologic processes of the brain following mild traumatic brain injury (mTBI). Previous studies report axonal injury and oedema in the first week after injury in a rodent model. This study aims to investigate the processes occurring 1 week after injury at the time of regeneration and degeneration using diffusion tensor imaging (DTI) in the impact acceleration rat mTBI model. RESEARCH DESIGN: Eighteen rats were subjected to impact acceleration injury, and three rats served as sham controls. Seven days post injury, DTI was acquired from fixed rat brains using a 7T scanner. Group comparison of Fractional Anisotropy (FA) values between traumatized and sham animals was performed using Tract-Based Spatial Statistics (TBSS), a method that we adapted for rats. MAIN OUTCOMES AND RESULTS: TBSS revealed white matter regions of the brain with increased FA values in the traumatized versus sham rats, localized mainly to the contrecoup region. Regions of increased FA included the pyramidal tract, the cerebral peduncle, the superior cerebellar peduncle and to a lesser extent the fibre tracts of the corpus callosum, the anterior commissure, the fimbria of the hippocampus, the fornix, the medial forebrain bundle and the optic chiasm. CONCLUSION: Seven days post injury, during the period of tissue reparation in the impact acceleration rat model of mTBI, microstructural changes to white matter can be detected using DTI.


Assuntos
Concussão Encefálica/diagnóstico por imagem , Imagem de Tensor de Difusão , Regeneração Nervosa/fisiologia , Substância Branca/diagnóstico por imagem , Animais , Anisotropia , Masculino , Modelos Animais , Projetos Piloto , Ratos , Ratos Sprague-Dawley
16.
Anal Chem ; 88(18): 9103-10, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27532481

RESUMO

Lipids from different classes sometimes can exhibit the same exact mass upon electrospray ionization; this presents an analytical challenge in lipidomics. In the negative ionization mode, for example, this can occur with phosphatidylcholines (PCs) and phosphatidylserines (PSs), making them indistinguishable in the absence of fragmentation data. PSs are found at low concentrations in biological samples, making MS/MS spectra difficult to obtain. Moreover, while PCs and PSs are distinguishable in the positive mode, PSs do not ionize as well as PCs, and their ionization is suppressed by the PCs. Here, we show that, in the negative ionization mode, substituting protiated LC-MS additives with their deuterated forms provides a way to distinguish PCs and PSs without chemical derivatization. The method described leverages the differential ionization mechanism of PCs and PSs. PCs are ionized via adduction with salts, whereas PSs ionize via hydrogen abstraction. Substituting the salts used for LC-MS with their deuterated form shifts the mass of PCs by the number of deuterium atoms in the salt, while the mass of PSs remains the same. This comparative shift enables their direct differentiation. We demonstrate that the use of deuterated formate shifts the mass of PCs and provides a direct method to distinguish PCs and PSs, even at biologically relevant low concentrations. The utility of the method was established and validated in the simultaneous analysis of PCs and PSs in lipid extracts from isolated liver mitochondria in two different rat strains. Thirteen low concentration PSs were identified that would otherwise not have been distinguishable from low concentration PCs.


Assuntos
Espectrometria de Massas/métodos , Mitocôndrias Hepáticas/química , Fosfatidilcolinas/análise , Fosfatidilserinas/análise , Animais , Cromatografia Líquida/métodos , Deutério/análise , Masculino , Ratos
17.
Adipocyte ; 5(2): 163-74, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27386152

RESUMO

The adipose organ, which comprises brown, white and beige adipocytes, possesses remarkable plasticity in response to feeding and cold exposure. The development of beige adipocytes in white adipose tissue (WAT), a process called browning, represents a promising route to treat metabolic disorders. While surgical procedures constantly traumatize adipose tissue, its impact on adipocyte phenotype remains to be established. Herein, we studied the effect of trauma on adipocyte phenotype one day after sham, incision control, or surgical injury to the left inguinal adipose compartment. Caloric restriction was used to control for surgery-associated body temperature changes and weight loss. We characterized the trauma-induced cellular and molecular changes in subcutaneous, visceral, interscapular, and perivascular adipose tissue using histology, immunohistochemistry, gene expression, and flow cytometry analysis. After one day, surgical trauma stimulated adipose tissue browning at the site of injury and, importantly, in the contralateral inguinal depot. Browning was not present after incision only, and was largely independent of surgery-associated body temperature and weight loss. Adipose trauma rapidly recruited monocytes to the injured site and promoted alternatively activated macrophages. Conversely, PDGF receptor-positive beige progenitors were reduced. In this study, we identify adipose trauma as an unexpected driver of selected local and remote adipose tissue browning, holding important implications for the biologic response to surgical injury.

18.
NPJ Aging Mech Dis ; 2: 16022, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28721274

RESUMO

Accumulation of DNA damage is intricately linked to aging, aging-related diseases and progeroid syndromes such as Cockayne syndrome (CS). Free radicals from endogenous oxidative energy metabolism can damage DNA, however the potential of acute or chronic DNA damage to modulate cellular and/or organismal energy metabolism remains largely unexplored. We modeled chronic endogenous genotoxic stress using a DNA repair-deficient Csa-/-|Xpa-/- mouse model of CS. Exogenous genotoxic stress was modeled in mice in vivo and primary cells in vitro treated with different genotoxins giving rise to diverse spectrums of lesions, including ultraviolet radiation, intrastrand crosslinking agents and ionizing radiation. Both chronic endogenous and acute exogenous genotoxic stress increased mitochondrial fatty acid oxidation (FAO) on the organismal level, manifested by increased oxygen consumption, reduced respiratory exchange ratio, progressive adipose loss and increased FAO in tissues ex vivo. In multiple primary cell types, the metabolic response to different genotoxins manifested as a cell-autonomous increase in oxidative phosphorylation (OXPHOS) subsequent to a transient decline in steady-state NAD+ and ATP levels, and required the DNA damage sensor PARP-1 and energy-sensing kinase AMPK. We conclude that increased FAO/OXPHOS is a general, beneficial, adaptive response to DNA damage on cellular and organismal levels, illustrating a fundamental link between genotoxic stress and energy metabolism driven by the energetic cost of DNA damage. Our study points to therapeutic opportunities to mitigate detrimental effects of DNA damage on primary cells in the context of radio/chemotherapy or progeroid syndromes.

19.
J Vasc Surg ; 63(2): 500-9.e1, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25124359

RESUMO

OBJECTIVE: Whereas chronic overnutrition is a risk factor for surgical complications, long-term dietary restriction (reduced food intake without malnutrition) protects in preclinical models of surgical stress. Building on the emerging concept that acute preoperative dietary perturbations can affect the body's response to surgical stress, we hypothesized that short-term high-fat diet (HFD) feeding before surgery is detrimental, whereas short-term nutrient/energy restriction before surgery can reverse negative outcomes. We tested this hypothesis in two distinct murine models of vascular surgical injury, ischemia-reperfusion (IR) and intimal hyperplasia (IH). METHODS: Short-term overnutrition was achieved by feeding mice a HFD consisting of 60% calories from fat for 2 weeks. Short-term dietary restriction consisted of either 1 week of restricted access to a protein-free diet (protein/energy restriction) or 3 days of water-only fasting immediately before surgery; after surgery, all mice were given ad libitum access to a complete diet. To assess the impact of preoperative nutrition on surgical outcome, mice were challenged in one of two fundamentally distinct surgical injury models: IR injury to either kidney or liver, or a carotid focal stenosis model of IH. RESULTS: Three days of fasting or 1 week of preoperative protein/energy restriction attenuated IH development measured 28 days after focal carotid stenosis. One week of preoperative protein/energy restriction also reduced plasma urea, creatinine, and damage to the corticomedullary junction after renal IR and decreased aspartate transaminase, alanine transaminase, and hemorrhagic necrosis after hepatic IR. However, exposure to a HFD for 2 weeks before surgery had no significant impact on kidney or hepatic function after IR or IH after focal carotid stenosis. CONCLUSIONS: Short-term dietary restriction immediately before surgery significantly attenuated the vascular wall hyperplastic response and improved IR outcome. The findings suggest plasticity in the body's response to these vascular surgical injuries that can be manipulated by novel yet practical preoperative dietary interventions.


Assuntos
Restrição Calórica , Estenose das Carótidas/dietoterapia , Dieta com Restrição de Proteínas , Rim/irrigação sanguínea , Fígado/irrigação sanguínea , Neointima , Traumatismo por Reperfusão/prevenção & controle , Animais , Biomarcadores/sangue , Estenose das Carótidas/etiologia , Estenose das Carótidas/patologia , Creatinina/sangue , Dieta Hiperlipídica , Modelos Animais de Doenças , Ingestão de Energia , Rim/patologia , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Cuidados Pré-Operatórios , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/patologia , Fatores de Tempo , Ureia/sangue
20.
J Vasc Surg ; 63(1): 171-6.e1, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25264363

RESUMO

OBJECTIVE: Substantial proportions of autogenous arteriovenous fistulas (AVFs) for hemodialysis access fail to mature for unclear reasons. AVFs develop in a large mass of surrounding adipose tissue that is increasingly recognized as an active participant in the vascular response to injury via paracrine and endocrine mechanisms. We thus hypothesized that baseline phenotypic characteristics of the adipose tissue juxtaposed to the developing AVF associate with subsequent inward or outward vein wall remodeling. METHODS: Clinical data and subcutaneous adipose tissue were collected from 22 consented patients undergoing AVF creation. Tissue was assayed (protein levels) for interleukin (IL)-6, IL-8, leptin, tumor necrosis factor-α, monocyte chemoattractant protein-1 (MCP-1), resistin, and adiponectin. Vein dimensions were acquired by duplex ultrasound imaging, preoperatively and at 4 to 6 weeks postoperatively, 1 cm cephalad to the arteriovenous anastomosis, which is the most common location of AVF stenosis). RESULTS: The vein at the assayed location outwardly remodeled 55.7% on average (median before, 3.7 mm; median after, 4.7 mm; P = .005). The preoperative vein diameter failed to correlate with postoperative size at the point of assay (R = 0.31; P = .155) unless two outliers were excluded (R = 0.64; P = .002). After removal of the same outliers, the correlation coefficient between venous diameter change (preoperative vs postoperative) and IL-8, tumor necrosis factor-α, MCP-1, resistin, and adiponectin was -0.49, -0.79, -0.66, -0.64, and -0.69, respectively (P < .05). Postoperative AVF flow volume correlated with MCP-1 (R = -0.53; P < .05) and adiponectin (R = -0.47; P < .05). CONCLUSIONS: These data reveal a novel relationship between local adipose phenotype and the eventual venous wall response to hemodynamic perturbation in humans. The predictive value of these mediators generally equaled or exceeded that of preoperative vein size. Beyond providing mechanistic insights into vascular wall adaptations due to flow perturbations, this discovery suggests that strategies focused on altering adipose tissue biology may improve AVF maturation.


Assuntos
Derivação Arteriovenosa Cirúrgica/efeitos adversos , Oclusão de Enxerto Vascular/etiologia , Diálise Renal , Gordura Subcutânea/metabolismo , Remodelação Vascular , Veias/cirurgia , Idoso , Biomarcadores/metabolismo , Feminino , Oclusão de Enxerto Vascular/diagnóstico , Oclusão de Enxerto Vascular/metabolismo , Oclusão de Enxerto Vascular/fisiopatologia , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Estudos Prospectivos , Fatores de Risco , Fatores de Tempo , Falha de Tratamento , Ultrassonografia Doppler de Pulso , Veias/diagnóstico por imagem , Veias/fisiopatologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...