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1.
Front Oncol ; 9: 1241, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31803619

RESUMO

Purpose: To retrospectively identify the relationships between both CT morphological features and histogram parameters with pulmonary metastasis in patients with colorectal cancer (CRC) and compare the efficacy of single-slice and whole-lesion histogram analysis. Methods: Our study enrolled 196 CRC patients with pulmonary nodules (136 in the training dataset and 60 in the validation dataset). Twenty morphological features of contrast-enhanced chest CT were evaluated. The regions of interests were delineated in single-slice and whole-tumor lesions, and 22 histogram parameters were extracted. Stepwise logistic regression analyses were applied to choose the independent factors of lung metastasis in the morphological features model, the single-slice histogram model and whole-lesion histogram model. The areas under the curve (AUC) was applied to quantify the predictive accuracy of each model. Finally, we built a morphological-histogram nomogram for pulmonary metastasis prediction. Results: The whole-lesion histogram analysis (AUC of 0.888 and 0.865 in the training and validation datasets, respectively) outperformed the single-slice histogram analysis (AUC of 0.872 and 0.819 in the training and validation datasets, respectively) and the CT morphological features model (AUC of 0.869 and 0.845 in the training and validation datasets, respectively). The morphological-histogram model, developed with significant morphological features and whole-lesion histogram parameters, achieved favorable discrimination in both the training dataset (AUC = 0.919) and validation dataset (AUC = 0.895), and good calibration. Conclusions: CT morphological features in combination with whole-lesion histogram parameters can be used to prognosticate pulmonary metastasis for patients with colorectal cancer.

2.
Pharmacol Res Perspect ; 7(6): e00543, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31832204

RESUMO

Anacetrapib is an inhibitor of cholesteryl ester transfer protein (CETP) previously under development as a lipid-modifying agent that reduces LDL-cholesterol and increases HDL-cholesterol in hypercholesterolemic patients. Anacetrapib demonstrates a long terminal half-life and accumulates in adipose tissue, which contributes to a long residence time of anacetrapib. Given our previous report that anacetrapib distributes into the lipid droplet of adipose tissue, we sought to understand whether anacetrapib affected adipose function, using a diet-induced obese (DIO) mouse model. Following 20 weeks of treatment with anacetrapib (100 mg/kg/day), levels of the drug increased to approximately 0.6 mmol/L in white adipose tissue. This level of anacetrapib was not associated with any impairment in adipose functionality as evidenced by a lack of any reduction in biomarkers of adipose functionality (plasma adiponectin, leptin, insulin; adipose adiponectin, leptin mRNA). In DIO wild-type (WT) mice treated with anacetrapib for 2 weeks and then subjected to 30% food restriction during washout to induce weight loss (18%) and fat mass loss (7%), levels of anacetrapib in adipose and plasma were not different between food restricted and ad lib-fed mice. These data indicate that despite deposition and long-term residence of ~0.6 mmol/L levels of anacetrapib in adipose tissue, adipose tissue function appears to be unaffected in mice. In addition, these data also indicate that even with severe caloric restriction and acute loss of fat mass, anacetrapib does not appear to be mobilized from the fat depot, thereby solidifying the role of adipose as a long-term storage site of anacetrapib.

3.
Drug Metab Dispos ; 47(3): 227-233, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30567880

RESUMO

Anacetrapib is an inhibitor of cholesteryl ester transfer protein (CETP), associated with reduction in LDL cholesterol and increase in HDL cholesterol in hypercholesterolemic patients. Anacetrapib was not taken forward into filing/registration as a new drug for coronary artery diease, despite the observation of a ∼9% reduction in cardiovascular risk in a large phase III cardiovascular outcomes trial (REVEAL). Anacetrapib displayed no adverse effects throughout extensive preclinical safety evaluation, and no major safety signals were observed in clinical trials studying anacetrapib, including REVEAL. However, anacetrapib demonstrated a long terminal half-life in all species, thought to be due, in part, to distribution into adipose tissue. We sought to understand the dependence of anacetrapib's long half-life on adipose tissue and to explore potential mechanisms that might contribute to the phenomenon. In mice, anacetrapib localized primarily to the lipid droplet of adipocytes in white adipose tissue; in vitro, anacetrapib entry into cultured human adipocytes depended on the presence of a mature adipocyte and lipid droplet but did not require active transport. In vivo, the entry of anacetrapib into adipose tissue did not require lipase activity, as the distribution of anacetrapib into adipose was-not affected by systemic lipase inhibition using poloaxamer-407, a systemic lipase inhibitor. The data from these studies support the notion that the entry of anacetrapib into adipose tissue/lipid droplets does not require active transport, nor does it require mobilization or entry of fat into adipose via lipolysis.


Assuntos
Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Proteínas de Transferência de Ésteres de Colesterol/antagonistas & inibidores , Gotículas Lipídicas/metabolismo , Oxazolidinonas/farmacologia , Adipócitos/citologia , Tecido Adiposo/citologia , Animais , Linhagem Celular , HDL-Colesterol/sangue , HDL-Colesterol/metabolismo , LDL-Colesterol/sangue , LDL-Colesterol/metabolismo , Meia-Vida , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases , Hipercolesterolemia/sangue , Hipercolesterolemia/tratamento farmacológico , Lipase/antagonistas & inibidores , Lipase/metabolismo , Lipólise/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxazolidinonas/administração & dosagem , Oxazolidinonas/uso terapêutico , Poloxâmero/farmacologia , Distribuição Tecidual/efeitos dos fármacos
4.
Eur Radiol ; 29(2): 889-897, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29967956

RESUMO

OBJECTIVES: To identify the radiomics signature allowing preoperative discrimination of lung invasive adenocarcinomas from non-invasive lesions manifesting as ground-glass nodules. METHODS: This retrospective primary cohort study included 160 pathologically confirmed lung adenocarcinomas. Radiomics features were extracted from preoperative non-contrast CT images to build a radiomics signature. The predictive performance and calibration of the radiomics signature were evaluated using intra-cross (n=76), external non-contrast-enhanced CT (n=75) and contrast-enhanced CT (n=84) validation cohorts. The performance of radiomics signature and CT morphological and quantitative indices were compared. RESULTS: 355 three-dimensional radiomics features were extracted, and two features were identified as the best discriminators to build a radiomics signature. The radiomics signature showed a good ability to discriminate between invasive adenocarcinomas and non-invasive lesions with an accuracy of 86.3%, 90.8%, 84.0% and 88.1%, respectively, in the primary and validation cohorts. It remained an independent predictor after adjusting for traditional preoperative factors (odds ratio 1.87, p < 0.001) and demonstrated good calibration in all cohorts. It was a better independent predictor than CT morphology or mean CT value. CONCLUSIONS: The radiomics signature showed good predictive performance in discriminating between invasive adenocarcinomas and non-invasive lesions. Being a non-invasive biomarker, it could assist in determining therapeutic strategies for lung adenocarcinoma. KEY POINTS: • The radiomics signature was a non-invasive biomarker of lung invasive adenocarcinoma. • The radiomics signature outweighed CT morphological and quantitative indices. • A three-centre study showed that radiomics signature had good predictive performance.


Assuntos
Adenocarcinoma de Pulmão/diagnóstico por imagem , Adenocarcinoma de Pulmão/patologia , Biomarcadores Tumorais , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Tomografia Computadorizada Multidetectores/métodos , Cuidados Pré-Operatórios/métodos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Interpretação de Imagem Radiográfica Assistida por Computador , Estudos Retrospectivos
5.
Eur Radiol ; 29(1): 439-449, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29948074

RESUMO

OBJECTIVES: To develop and validate a clinical-radiomics nomogram for preoperative prediction of lung metastasis for colorectal cancer (CRC) patients with indeterminate pulmonary nodules (IPN). METHODS: 194 CRC patients with lung nodules were enrolled in this study (136 in the training cohort and 58 in the validation cohort). To evaluate the probability of lung metastasis, we developed three models, the clinical model with significant clinical risk factors, the radiomics model with radiomics features constructed by the least absolute shrinkage and selection operator algorithm, and the clinical-radiomics model with significant variables selected by the stepwise logistic regression. The Akaike information criterion (AIC) was used to compare the relative strength of different models, and the area under the curve (AUC) was used to quantify the predictive accuracy. The nomogram was developed based on the most appropriate model. Decision-curve analysis was applied to assess the clinical usefulness. RESULTS: The clinical-radiomics model (AIC = 98.893) with the lowest AIC value compared with that of the clinical-only model (AIC = 138.502) or the radiomics-only model (AIC = 116.146) was identified as the best model. The clinical-radiomics nomogram was also successfully developed with favourable discrimination in both training cohort (AUC = 0.929, 95% CI: 0.885-0.974) and validation cohort (AUC = 0.922, 95% CI: 0.857-0.986), and good calibration. Decision-curve analysis confirmed the clinical utility of the clinical-radiomics nomogram. CONCLUSIONS: In CRC patients with IPNs, the clinical-radiomics nomogram created by the radiomics signature and clinical risk factors exhibited favourable discriminatory ability and accuracy for a metastasis prediction. KEY POINTS: • Clinical features can predict lung metastasis of colorectal cancer patients. • Radiomics analysis outperformed clinical features in assessing the risk of pulmonary metastasis. • A clinical-radiomics nomogram can help clinicians predict lung metastasis in colorectal cancer patients.


Assuntos
Algoritmos , Neoplasias Colorretais/secundário , Neoplasias Pulmonares/diagnóstico , Nódulos Pulmonares Múltiplos/diagnóstico , Nomogramas , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
6.
Am J Physiol Endocrinol Metab ; 315(3): E416-E424, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29509438

RESUMO

Numerous studies have implicated dyslipidemia as a key factor in mediating insulin resistance. Ceramides have received special attention since their levels are inversely associated with normal insulin signaling and positively associated with factors that are involved in cardiometabolic disease. Despite the growing literature surrounding ceramide biology, there are limited data regarding the activity of ceramide synthesis and turnover in vivo. Herein, we demonstrate the ability to measure ceramide kinetics by coupling the administration of [2H]water with LC-MS/MS analyses. As a "proof-of-concept" we determined the effect of a diet-induced alteration on ceramide flux; studies also examined the effect of myriocin (a known inhibitor of serine palmitoyltransferase, the first step in sphingosine biosynthesis). Our data suggest that one can estimate ceramide synthesis and draw conclusions regarding the source of fatty acids; we discuss caveats in regards to method development in this area.


Assuntos
Ceramidas/farmacocinética , Animais , Cromatografia Líquida de Alta Pressão , Óxido de Deutério/farmacocinética , Dieta , Inibidores Enzimáticos , Ácidos Graxos Monoinsaturados/farmacologia , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Traçadores Radioativos , Serina C-Palmitoiltransferase/antagonistas & inibidores , Espectrometria de Massas em Tandem
8.
Nature ; 550(7675): 255-259, 2017 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-28953886

RESUMO

Under homeostatic conditions, animals use well-defined hypothalamic neural circuits to help maintain stable body weight, by integrating metabolic and hormonal signals from the periphery to balance food consumption and energy expenditure. In stressed or disease conditions, however, animals use alternative neuronal pathways to adapt to the metabolic challenges of altered energy demand. Recent studies have identified brain areas outside the hypothalamus that are activated under these 'non-homeostatic' conditions, but the molecular nature of the peripheral signals and brain-localized receptors that activate these circuits remains elusive. Here we identify glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) as a brainstem-restricted receptor for growth and differentiation factor 15 (GDF15). GDF15 regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses; we show that Gfral knockout mice are hyperphagic under stressed conditions and are resistant to chemotherapy-induced anorexia and body weight loss. GDF15 activates GFRAL-expressing neurons localized exclusively in the area postrema and nucleus tractus solitarius of the mouse brainstem. It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitute part of the 'emergency circuit' that shapes feeding responses to stressful conditions. GDF15 levels increase in response to tissue stress and injury, and elevated levels are associated with body weight loss in numerous chronic human diseases. By isolating GFRAL as the receptor for GDF15-induced anorexia and weight loss, we identify a mechanistic basis for the non-homeostatic regulation of neural circuitry by a peripheral signal associated with tissue damage and stress. These findings provide opportunities to develop therapeutic agents for the treatment of disorders with altered energy demand.


Assuntos
Peso Corporal/fisiologia , Tronco Encefálico/metabolismo , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Fator 15 de Diferenciação de Crescimento/metabolismo , Animais , Tronco Encefálico/citologia , Tronco Encefálico/efeitos dos fármacos , Núcleo Central da Amígdala/citologia , Núcleo Central da Amígdala/fisiologia , Ingestão de Alimentos/fisiologia , Metabolismo Energético/fisiologia , Comportamento Alimentar , Feminino , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/deficiência , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Fator 15 de Diferenciação de Crescimento/genética , Fator 15 de Diferenciação de Crescimento/farmacologia , Homeostase , Masculino , Camundongos , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Núcleos Parabraquiais/citologia , Núcleos Parabraquiais/fisiologia , Estresse Psicológico
10.
J Pharmacol Exp Ther ; 363(1): 80-91, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28724692

RESUMO

Drug discovery and development efforts are largely based around a common expectation, namely, that direct or indirect action on a cellular process (e.g., statin-mediated enzyme inhibition or insulin-stimulated receptor activation) will have a beneficial impact on physiologic homeostasis. To expand on this, one could argue that virtually all pharmacologic interventions attempt to influence the flow of "traffic" in a biochemical network, irrespective of disease or modality. Since stable isotope tracer kinetic methods provide a measure of traffic flow (i.e., metabolic flux), their inclusion in study designs can yield novel information regarding pathway biology; the application of such methods requires the integration of knowledge in physiology, analytical chemistry, and mathematical modeling. Herein, we review the fundamental concepts that surround the use of tracer kinetics, define basic terms, and outline guiding principles via theoretical and experimental problems. Specifically, one needs to 1) recognize the types of biochemical events that change isotopic enrichments, 2) appreciate the distinction between fractional turnover and flux rate, and 3) be aware of the subtle differences between tracer kinetics and pharmacokinetics. We hope investigators can use the framework presented here to develop applications that address their specific questions surrounding biochemical flux, and thereby gain insight into the pathophysiology of disease states, and examine pharmacodynamic mechanisms.


Assuntos
Descoberta de Drogas/métodos , Análise do Fluxo Metabólico/métodos , Animais , Humanos , Marcação por Isótopo , Isótopos/química , Água/química , Água/metabolismo
11.
J Lipid Res ; 58(8): 1561-1578, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28583918

RESUMO

GPR40 and GPR120 are fatty acid sensors that play important roles in glucose and energy homeostasis. GPR40 potentiates glucose-dependent insulin secretion and demonstrated in clinical studies robust glucose lowering in type 2 diabetes. GPR120 improves insulin sensitivity in rodents, albeit its mechanism of action is not fully understood. Here, we postulated that the antidiabetic efficacy of GPR40 could be enhanced by coactivating GPR120. A combination of GPR40 and GPR120 agonists in db/db mice, as well as a single molecule with dual agonist activities, achieved superior glycemic control compared with either monotherapy. Compared with a GPR40 selective agonist, the dual agonist improved insulin sensitivity in ob/ob mice measured by hyperinsulinemic-euglycemic clamp, preserved islet morphology, and increased expression of several key lipolytic genes in adipose tissue of Zucker diabetic fatty rats. Novel insights into the mechanism of action for GPR120 were obtained. Selective GPR120 activation suppressed lipolysis in primary white adipocytes, although this effect was attenuated in adipocytes from obese rats and obese rhesus, and sensitized the antilipolytic effect of insulin in rat and rhesus primary adipocytes. In conclusion, GPR120 agonism enhances insulin action in adipose tissue and yields a synergistic efficacy when combined with GPR40 agonism.


Assuntos
Tecido Adiposo/metabolismo , Diabetes Mellitus Experimental/metabolismo , Lipólise , Receptores Acoplados a Proteínas-G/metabolismo , Tecido Adiposo/efeitos dos fármacos , Animais , Células CHO , Cricetinae , Cricetulus , Diabetes Mellitus Experimental/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Resistência à Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/fisiopatologia , Lipólise/efeitos dos fármacos , Masculino , Camundongos , Ratos , Receptores Acoplados a Proteínas-G/agonistas
12.
J Lipid Res ; 57(12): 2150-2162, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27707816

RESUMO

SREBP cleavage-activating protein (SCAP) is a key protein in the regulation of lipid metabolism and a potential target for treatment of dyslipidemia. SCAP is required for activation of the transcription factors SREBP-1 and -2. SREBPs regulate the expression of genes involved in fatty acid and cholesterol biosynthesis, and LDL-C clearance through the regulation of LDL receptor (LDLR) and PCSK9 expression. To further test the potential of SCAP as a novel target for treatment of dyslipidemia, we used siRNAs to inhibit hepatic SCAP expression and assess the effect on PCSK9, LDLR, and lipids in mice and rhesus monkeys. In mice, robust liver Scap mRNA knockdown (KD) was achieved, accompanied by dose-dependent reduction in SREBP-regulated gene expression, de novo lipogenesis, and plasma PCSK9 and lipids. In rhesus monkeys, over 90% SCAP mRNA KD was achieved resulting in approximately 75, 50, and 50% reduction of plasma PCSK9, TG, and LDL-C, respectively. Inhibition of SCAP function was demonstrated by reduced expression of SREBP-regulated genes and de novo lipogenesis. In conclusion, siRNA-mediated inhibition of SCAP resulted in a significant reduction in circulating PCSK9 and LDL-C in rodent and primate models supporting SCAP as a novel target for the treatment of dyslipidemia.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/genética , Lipídeos/sangue , Proteínas de Membrana/genética , Pró-Proteína Convertase 9/genética , RNA Interferente Pequeno/genética , Receptores de LDL/genética , Animais , Feminino , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Hipolipemiantes/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lipogênese , Fígado/enzimologia , Macaca mulatta , Masculino , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Pró-Proteína Convertase 9/metabolismo , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de LDL/metabolismo , Transdução de Sinais , Sinvastatina/farmacologia , Proteínas de Ligação a Elemento Regulador de Esterol/genética , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo
13.
Am J Physiol Endocrinol Metab ; 311(6): E911-E921, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27651111

RESUMO

Aberrant regulation of glucose production makes a critical contribution to the impaired glycemic control that is observed in type 2 diabetes. Although isotopic tracer methods have proven to be informative in quantifying the magnitude of such alterations, it is presumed that one must rely on venous access to administer glucose tracers which therein presents obstacles for the routine application of tracer methods in rodent models. Since intraperitoneal injections are readily used to deliver glucose challenges and/or dose potential therapeutics, we hypothesized that this route could also be used to administer a glucose tracer. The ability to then reliably estimate glucose flux would require attention toward setting a schedule for collecting samples and choosing a distribution volume. For example, glucose production can be calculated by multiplying the fractional turnover rate by the pool size. We have taken a step-wise approach to examine the potential of using an intraperitoneal tracer administration in rat and mouse models. First, we compared the kinetics of [U-13C]glucose following either an intravenous or an intraperitoneal injection. Second, we tested whether the intraperitoneal method could detect a pharmacological manipulation of glucose production. Finally, we contrasted a potential application of the intraperitoneal method against the glucose-insulin clamp. We conclude that it is possible to 1) quantify glucose production using an intraperitoneal injection of tracer and 2) derive a "glucose production index" by coupling estimates of basal glucose production with measurements of fasting insulin concentration; this yields a proxy for clamp-derived assessments of insulin sensitivity of endogenous production.


Assuntos
Glicemia/metabolismo , Indicadores e Reagentes , Animais , Glicemia/efeitos dos fármacos , Isótopos de Carbono , Dieta Hiperlipídica , Feminino , Técnica Clamp de Glucose , Hipoglicemiantes/farmacologia , Injeções Intraperitoneais , Injeções Intravenosas , Resistência à Insulina , Cinética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Projetos Piloto , Ratos , Ratos Sprague-Dawley , Ratos Zucker , Rosiglitazona , Tiazolidinedionas/farmacologia
14.
Eur Radiol ; 26(9): 2947-55, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26787604

RESUMO

PURPOSE: To explore the value of in-line phase-contrast imaging with computed tomography (ILPCI-CT) by synchrotron radiation (SR) for liver fibrosis. MATERIALS AND METHODS: Liver fibrosis models were set up in 13 BALB/c mice by peritoneal injections of thioacetamide and evaluated by ILPCI-CT. Histological staging was used to categorize liver fibrosis into normal, mild fibrosis and advanced fibrosis groups. Microvessel density (MVD), the ratio of total vessel length to volume (L/V), the ratio of total number of branching points to liver volume (P/V) and the distribution of vessel diameter were assessed. RESULTS: The CT images showed slightly high-density shadows around the portal tracts in the fibrosis group. Three-dimensional reconstruction can detect vascular and nodular changes on the surface of fibrotic livers. The MVDs between the three groups were significantly different (P = 0.024). L/V was significantly different between the three groups (P = 0.014). There was a positive correlation between MVD and P/V. CONCLUSION: Fibrous material can be detected by ILPCI-CT even in the early stage of fibrosis. MVD, L/V, P/V and the distribution of vessel diameter were consistent with fibrosis-related angiogenesis progress. Three-dimensional reconstruction is a promising method to visualize morphological changes of the fibrotic liver. KEY POINTS: • ILPCI-CT can detect fibrous material even in the early stage of liver fibrosis. • MVD, L/V, P/V, and the distribution of vascular diameter reflect pathological angiogenesis. • 3D reconstruction could be a promising approach for detecting liver fibrosis.


Assuntos
Cirrose Hepática/diagnóstico por imagem , Cirrose Hepática/patologia , Microvasos/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Animais , Modelos Animais de Doenças , Fibrose , Masculino , Camundongos , Camundongos Endogâmicos BALB C
15.
Anal Bioanal Chem ; 408(1): 97-105, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26511226

RESUMO

Oxylipins are oxidation products of polyunsaturated fatty acids (PUFAs) that affect a broad range of physiological processes, including cell proliferation, inflammation, inflammation resolution, and vascular function. Moreover, oxylipins are readily detectable in plasma, and certain subsets of oxylipins have been detected in human atherosclerotic lesions. Taken together, we set out to produce a detailed quantitative assessment of plasma and plaque oxylipins in a widely used model of atherosclerosis, to identify potential biomarkers of disease progression. We administered regular chow or regular chow supplemented with 0.5% cholesterol (HC) to male New Zealand white rabbits for 12 weeks to induce hypercholesterolemia and atherosclerosis. Our targeted lipidomic analyses of oxylipins on plaques isolated from rabbits fed the HC diet detected 34 oxylipins, 28 of which were in compliance with our previously established quality control acceptance criteria. The arachidonic acid (AA) metabolite derived from the COX pathway, 6-keto-PGF1α was the most abundant plaque oxylipin, followed by the linoleic acid (LA) metabolites 9-HODE, 13-HODE and 9,12,13-TriHOME and the arachidonic acid (AA)-derivatives 11-HETE and 12-HETE. We additionally found that the most abundant oxylipins in plasma were three of the five most abundant oxylipins in plaque, namely 11-HETE, 13-HODE, and 9-HODE. The studies reported here make the first step towards a comprehensive characterization of oxylipins as potentially translatable biomarkers of atherosclerosis.


Assuntos
Hipercolesterolemia/sangue , Oxilipinas/sangue , Placa Aterosclerótica/sangue , Animais , Cromatografia Líquida de Alta Pressão , Ácidos Graxos Insaturados/metabolismo , Humanos , Hipercolesterolemia/metabolismo , Masculino , Espectrometria de Massas , Oxilipinas/metabolismo , Placa Aterosclerótica/metabolismo , Coelhos
16.
J Med Chem ; 58(23): 9345-53, 2015 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-26561979

RESUMO

DGAT2 plays a critical role in hepatic triglyceride production, and data suggests that inhibition of DGAT2 could prove to be beneficial in treating a number of disease states. This article documents the discovery and optimization of a selective small molecule inhibitor of DGAT2 as well as pharmacological proof of biology in a mouse model of triglyceride production.


Assuntos
Diacilglicerol O-Aciltransferase/antagonistas & inibidores , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Isoquinolinas/química , Isoquinolinas/farmacologia , Triglicerídeos/metabolismo , Animais , Diacilglicerol O-Aciltransferase/metabolismo , Descoberta de Drogas , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacocinética , Humanos , Isoquinolinas/administração & dosagem , Isoquinolinas/farmacocinética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Triglicerídeos/sangue
17.
Methods Enzymol ; 561: 331-58, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26358910

RESUMO

Stable isotope tracers are widely used to quantify metabolic rates, and yet a limited number of studies have considered the impact of analytical error on estimates of flux. For example, when estimating the contribution of de novo lipogenesis, one typically measures a minimum of four isotope ratios, i.e., the precursor and product labeling pre- and posttracer administration. This seemingly simple problem has 1 correct solution and 80 erroneous outcomes. In this report, we outline a methodology for evaluating the effect of error propagation on apparent physiological endpoints. We demonstrate examples of how to evaluate the influence of analytical error in case studies concerning lipid and protein synthesis; we have focused on (2)H2O as a tracer and contrast different mass spectrometry platforms including GC-quadrupole-MS, GC-pyrolysis-IRMS, LC-quadrupole-MS, and high-resolution FT-ICR-MS. The method outlined herein can be used to determine how to minimize variations in the apparent biology by altering the dose and/or the type of tracer. Likewise, one can facilitate biological studies by estimating the reduction in the noise of an outcome that is expected for a given increase in the number of replicate injections.


Assuntos
Marcação por Isótopo/métodos , Espectrometria de Massas/métodos , Metabolismo , Animais , Isótopos de Carbono , Cromatografia Gasosa/métodos , Cromatografia Líquida/métodos , Óxido de Deutério , Humanos , Razão Sinal-Ruído
18.
J Lipid Res ; 56(11): 2183-95, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26373568

RESUMO

Glucagon and insulin have opposing action in governing glucose homeostasis. In type 2 diabetes mellitus (T2DM), plasma glucagon is characteristically elevated, contributing to increased gluconeogenesis and hyperglycemia. Therefore, glucagon receptor (GCGR) antagonism has been proposed as a pharmacologic approach to treat T2DM. In support of this concept, a potent small-molecule GCGR antagonist (GRA), MK-0893, demonstrated dose-dependent efficacy to reduce hyperglycemia, with an HbA1c reduction of 1.5% at the 80 mg dose for 12 weeks in T2DM. However, GRA treatment was associated with dose-dependent elevation of plasma LDL-cholesterol (LDL-c). The current studies investigated the cause for increased LDL-c. We report findings that link MK-0893 with increased glucagon-like peptide 2 and cholesterol absorption. There was not, however, a GRA-related modulation of cholesterol synthesis. These findings were replicated using structurally diverse GRAs. To examine potential pharmacologic mitigation, coadministration of ezetimibe (a potent inhibitor of cholesterol absorption) in mice abrogated the GRA-associated increase of LDL-c. Although the molecular mechanism is unknown, our results provide a novel finding by which glucagon and, hence, GCGR antagonism govern cholesterol metabolism.


Assuntos
Colesterol/sangue , Pirazóis/farmacologia , Receptores de Glucagon/antagonistas & inibidores , beta-Alanina/análogos & derivados , Animais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos , Humanos , Hipercolesterolemia/induzido quimicamente , Concentração Inibidora 50 , Absorção Intestinal , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pirazóis/efeitos adversos , beta-Alanina/efeitos adversos , beta-Alanina/farmacologia
19.
J Zhejiang Univ Sci B ; 16(6): 524-32, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26055914

RESUMO

The energy homeostasis-associated (Enho) gene encodes a secreted protein, adropin, which regulates the expression of hepatic lipogenic genes and adipose tissue peroxisome proliferator-activated receptor γ, a major regulator of lipogenesis. In the present study, the porcine (Sus scrofa) homologue of the Enho gene, which was named pEnho, was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using oligonucleotide primers derived from in silico sequences. The gene sequence was submitted into the GenBank of NCBI, and the access number is GQ414763. The pEnho encodes a protein of 76 amino acids which shows 75% similarity to Homo sapiens adropin. The expression profile of pEnho in tissues (liver, muscle, anterior jejunum, posterior jejunum, and ileum) was determined by quantitative real-time RT-PCR. pEnho was localized on porcine chromosome 10 and no introns were found. In conclusion, pEnho was cloned and analysed with the aim of increasing knowledge about glucose and lipid metabolism in piglets and helping to promote the health and growth of piglets through adropin regulation.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Suínos/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Dados de Sequência Molecular , Especificidade de Órgãos , Suínos/genética , Distribuição Tecidual
20.
Eur J Pharmacol ; 762: 256-62, 2015 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-26049012

RESUMO

The increase in high density lipoprotein (HDL)-cholesterol observed with cholesteryl ester transfer protein (CETP) inhibition is commonly attributed to blockade of cholesteryl ester (CE) transfer from HDL to low density lipoprotein particles. In vitro, it has been observed that CETP can mediate transfer of CE between HDL particles ("homotypic transfer"), and it is postulated that this contributes to HDL remodeling and generation of anti-atherogenic pre-beta HDL. Inhibition of CETP could limit this beneficial remodeling and reduce pre-beta HDL levels. We observed that anacetrapib does not reduce pre-beta HDL in vivo, but the role of HDL homotypic transfer was not examined. This study evaluated the effects of anacetrapib on homotypic transfer from HDL3 to HDL2 in vivo using deuterium-labeled HDL3, and compared this to in vitro settings, where homotypic transfer was previously described. In vitro, both anacetrapib and dalcetrapib inhibited transfer of CE from HDL3 to HDL2 particles. In CETP transgenic mice, anacetrapib did not inhibit the appearance of labeled CE derived from HDL3 in HDL2 particles, but rather promoted the appearance of labeled CE in HDL2. We concluded that inhibition of CETP by anacetrapib promoted HDL particle remodeling, and does not impair the flux of cholesterol ester into larger HDL particles when studied in vivo, which is not consistent with in vitro observations. We further conclude, therefore, that the in vitro conditions used to examine HDL-to-HDL homotypic transfer may not recapitulate the in vivo condition, where multiple mechanisms contribute to cholesteryl ester flux into and out of the HDL pool.


Assuntos
Anticolesterolemiantes/farmacologia , Proteínas de Transferência de Ésteres de Colesterol/antagonistas & inibidores , Ésteres do Colesterol/metabolismo , HDL-Colesterol/química , HDL-Colesterol/metabolismo , Oxazolidinonas/farmacologia , Compostos de Sulfidrila/farmacologia , Animais , VLDL-Colesterol/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL
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