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1.
J Clin Invest ; 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31805015

RESUMO

BACKGROUND: An increase in intrahepatic triglyceride (IHTG) is the hallmark feature of nonalcoholic fatty liver disease (NAFLD) and is decreased by weight loss. Hepatic de novo lipogenesis (DNL) contributes to steatosis in people with NAFLD. The physiological factors that stimulate hepatic DNL and the effect of weight loss on hepatic DNL are not clear. METHODS: Hepatic DNL, 24-h integrated plasma insulin and glucose concentrations, and both liver and whole-body insulin sensitivity were determined in people who were lean (n = 14), obese with normal IHTG content (Obese, n = 26) and obese with NAFLD (Obese-NAFLD, n = 27). Hepatic DNL was assessed by using the deuterated water method corrected for the potential confounding contribution of adipose tissue DNL. Liver and whole-body insulin sensitivity were assessed by using the hyperinsulinemic-euglycemic clamp procedure in conjunction with glucose tracer infusion. Six subjects in the Obese-NAFLD group were also evaluated before and after 10% diet-induced weight loss. RESULTS: The contribution of hepatic DNL to IHTG-palmitate was 11%, 19% and 38% in the Lean, Obese and Obese-NAFLD groups, respectively. Hepatic DNL was inversely correlated with hepatic and whole-body insulin sensitivity, but directly correlated with 24-h plasma glucose and insulin concentrations. Weight loss decreased IHTG content, in conjunction with a decrease in hepatic DNL and 24-h plasma glucose and insulin concentrations. CONCLUSIONS: These data suggest hepatic DNL is an important regulator of IHTG content, and that increases in circulating glucose and insulin stimulate hepatic DNL in people with NAFLD. Weight loss decreases IHTG content, at least in part, by decreasing hepatic DNL.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31837264

RESUMO

CONTEXT: The effect of sotagliflozin (a dual sodium-glucose cotransporter [SGLT]2 and SGLT1 inhibitor) on intestinal glucose absorption has not been investigated in humans. OBJECTIVE: To measure rate of appearance of oral glucose (RaO) using a dual glucose tracer method following standardized mixed meals taken after single sotagliflozin or canagliflozin doses. SETTING: Clinical research organization. DESIGN AND PARTICIPANTS: In double-blind, three-period crossover study NCT01916863, 24 healthy participants were randomized to two cohorts of 12 participants. Within each cohort, participants were randomly assigned single oral doses of either sotagliflozin 400 mg, canagliflozin 300 mg, or placebo on each of test days 1, 8, and 15. On test days, Cohort 1 had breakfast containing [6,6-2H2] glucose 0.25 hours postdose and lunch containing [1-2H1] glucose 5.25 hours postdose; Cohort 2 had breakfast containing no labeled glucose 0.25 hours postdose and lunch containing [6,6-2H2] glucose 4.25 hours postdose. All participants received a 10-15-hour continuous [U-13C6] glucose infusion starting 5 hours before their first [6,6-2H2] glucose-containing meal. MAIN OUTCOME: RaO, postprandial glucose (PPG), and postprandial insulin. RESULTS: Sotagliflozin and canagliflozin decreased AUC0-1 hour and/or AUC0-2 hours for RaO, PPG, and insulin after breakfast and/or the 4.25-hour postdose lunch (P<0.05 versus placebo). After the 5.25-hour postdose lunch, sotagliflozin lowered RaO AUC0-1 hour and PPG AUC0-5 hours versus both placebo and canagliflozin (P<0.05). CONCLUSIONS: Sotagliflozin delayed and blunted intestinal glucose absorption after meals, resulting in lower PPG and insulin levels, likely due to prolonged local inhibition of intestinal SGLT1 that persisted for ≥5 hours after dosing.

3.
J Biol Chem ; 294(23): 9213-9224, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31053639

RESUMO

Chronic or excess glucocorticoid exposure causes lipid disorders such as hypertriglyceridemia and hepatic steatosis. Angptl4 (angiopoietin-like 4), a primary target gene of the glucocorticoid receptor in hepatocytes and adipocytes, is required for hypertriglyceridemia and hepatic steatosis induced by the synthetic glucocorticoid dexamethasone. Angptl4 has also been shown to be required for dexamethasone-induced hepatic ceramide production. Here, we further examined the role of ceramide-mediated signaling in hepatic dyslipidemia caused by chronic glucocorticoid exposure. Using a stable isotope-labeling technique, we found that dexamethasone treatment induced the rate of hepatic de novo lipogenesis and triglyceride synthesis. These dexamethasone responses were compromised in Angptl4-null mice (Angptl4-/-). Treating mice with myriocin, an inhibitor of the rate-controlling enzyme of de novo ceramide synthesis, serine palmitoyltransferase long-chain base subunit 1 (SPTLC1)/SPTLC2, decreased dexamethasone-induced plasma and liver triglyceride levels in WT but not Angptl4-/- mice. We noted similar results in mice infected with adeno-associated virus-expressing small hairpin RNAs targeting Sptlc2. Protein phosphatase 2 phosphatase activator (PP2A) and protein kinase Cζ (PKCζ) are two known downstream effectors of ceramides. We found here that mice treated with an inhibitor of PKCζ, 2-acetyl-1,3-cyclopentanedione (ACPD), had lower levels of dexamethasone-induced triglyceride accumulation in plasma and liver. However, small hairpin RNA-mediated targeting of the catalytic PP2A subunit (Ppp2ca) had no effect on dexamethasone responses on plasma and liver triglyceride levels. Overall, our results indicate that chronic dexamethasone treatment induces an ANGPTL4-ceramide-PKCζ axis that activates hepatic de novo lipogenesis and triglyceride synthesis, resulting in lipid disorders.

4.
Sci Transl Med ; 11(492)2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-31092695

RESUMO

Sebum plays important physiological roles in human skin. Excess sebum production contributes to the pathogenesis of acne vulgaris, and suppression of sebum production reduces acne incidence and severity. We demonstrate that sebum production in humans depends on local flux through the de novo lipogenesis (DNL) pathway within the sebocyte. About 80 to 85% of sebum palmitate (16:0) and sapienate (16:1n10) were derived from DNL, based on stable isotope labeling, much higher than the contribution of DNL to triglyceride palmitate in circulation (~20%), indicating a minor contribution by nonskin sources to sebum lipids. This dependence on local sebocyte DNL was not recapitulated in two widely used animal models of sebum production, Syrian hamsters and Göttingen minipigs. Confirming the importance of DNL for human sebum production, an acetyl-CoA carboxylase inhibitor, ACCi-1, dose-dependently suppressed DNL and blocked synthesis of fatty acids, triglycerides, and wax esters but not free sterols in human sebocytes in vitro. ACCi-1 dose-dependently suppressed facial sebum excretion by ~50% (placebo adjusted) in human individuals dosed orally for 2 weeks. Sebum triglycerides, wax esters, and free fatty acids were suppressed by ~66%, whereas non-DNL-dependent lipid species, cholesterol, and squalene were not reduced, confirming selective modulation of DNL-dependent lipids. Last, individuals with acne vulgaris exhibited increased sebum production rates relative to individuals with normal skin, with >80% of palmitate and sapienate derived from DNL. These findings highlight the importance of local sebocyte DNL for human skin sebaceous gland biology and illuminate a potentially exploitable therapeutic target for the treatment of acne vulgaris.

5.
Diabetes ; 68(6): 1168-1177, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30936147

RESUMO

Patterns of abdominal fat distribution (for example, a high vs. low visceral adipose tissue [VAT]/[VAT + subcutaneous adipose tissue (SAT)] ratio), independent of obesity, during adolescence carry a high risk for insulin resistance and type 2 diabetes. Longitudinal follow-up of a cohort of obese adolescents has recently revealed that a high ratio (high VAT/[VAT + SAT]) is a major determinant of fatty liver and metabolic impairment over time, with these effects being more pronounced in girls than in boys. To unravel the underlying metabolic alterations associated with the unfavorable VAT/(VAT + SAT) phenotype, we used the 2H2O labeling method to measure the turnover of adipose lipids and cells in the subcutaneous abdominal and gluteal/femoral adipose tissue (SAT) of weight-stable obese adolescent girls with a similar level of obesity but discordant VAT/(VAT + SAT) ratios. Girls with the unfavorable (high VAT/[VAT + SAT]) phenotype exhibited higher in vivo rates of triglyceride (TG) turnover (representing both lipolysis and synthesis at steady state), without significant differences in de novo lipogenesis in both abdominal and gluteal depots, compared with obese girls with the favorable phenotype. Moreover, mature adipocytes had higher turnover, with no difference in stromal vascular cell proliferation in both depots in the metabolically unfavorable phenotype. The higher TG turnover rates were significantly correlated with higher intrahepatic fat stores. These findings are contrary to the hypothesis that impaired capacity to deposit TGs or proliferation of new mature adipocytes are potential mechanisms for ectopic fat distribution in this setting. In summary, these results suggest that increased turnover of TGs (lipolysis) and of mature adipocytes in both abdominal and gluteal SAT may contribute to metabolic impairment and the development of fatty liver, even at this very early stage of disease.


Assuntos
Adipócitos/metabolismo , Distribuição da Gordura Corporal , Obesidade/metabolismo , Gordura Subcutânea/metabolismo , Triglicerídeos/metabolismo , Absorciometria de Fóton , Adolescente , Óxido de Deutério , Feminino , Humanos , Gordura Intra-Abdominal/diagnóstico por imagem , Metabolismo dos Lipídeos , Lipogênese , Imagem por Ressonância Magnética , Obesidade Abdominal/diagnóstico por imagem , Obesidade Abdominal/metabolismo , Gordura Subcutânea/diagnóstico por imagem , Adulto Jovem
6.
J Cachexia Sarcopenia Muscle ; 10(1): 14-21, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30900400

RESUMO

Sarcopenia has been described as the age-associated decrease in skeletal muscle mass. However, virtually every study of sarcopenia has measured lean body mass (LBM) or fat free mass (FFM) rather than muscle mass, specifically. In a number of published sarcopenia studies, LBM or FFM is referred to as muscle mass, leading to an incorrect assumption that measuring LBM or FFM is an accurate measure of muscle mass. As a result, the data on the effects of changes in LBM or FFM in older populations on outcomes such as functional capacity, disability, and risk of injurious falls have been inconsistent resulting in the conclusion that muscle mass is only weakly related to these outcomes. We review and describe the assumptions for the most commonly used measurements of body composition. Dual-energy X-ray absorptiometry (DXA) has become an increasingly common tool for the assessment of LBM or FFM and appendicular lean mass as a surrogate, but inaccurate, measurement of muscle mass. Other previously used methods (total body water, bioelectric impedance, and imaging) also have significant limitations. D3 -Creatine (D3 -Cr) dilution provides a direct and accurate measurement of creatine pool size and skeletal muscle mass. In a recent study in older men (MrOS cohort), D3 -Cr muscle mass was associated with functional capacity and risk of injurious falls and disability, while assessments of LBM or appendicular lean mass by DXA were only weakly or not associated with these outcomes. Inaccurate measurements of muscle mass by DXA and other methods have led to inconsistent results and potentially erroneous conclusions about the importance of skeletal muscle mass in health and disease. The assessment of skeletal muscle mass using the D3 -Cr dilution method in prospective cohort studies may reveal sarcopenia as a powerful risk factor for late life disability and chronic disease.

7.
Cell Mol Life Sci ; 76(12): 2425-2447, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30788515

RESUMO

RDH1 is one of the several enzymes that catalyze the first of the two reactions to convert retinol into all-trans-retinoic acid (atRA). Here, we show that Rdh1-null mice fed a low-fat diet gain more weight as adiposity (17% males, 13% females) than wild-type mice by 20 weeks old, despite neither consuming more calories nor decreasing activity. Glucose intolerance and insulin resistance develop following increased adiposity. Despite the increase in white fat pads, epididymal white adipose does not express Rdh1, nor does muscle. Brown adipose tissue (BAT) and liver express Rdh1 at relatively high levels compared to other tissues. Rdh1 ablation lowered body temperatures during ambient conditions. Given the decreased body temperature, we focused on BAT. A lack of differences in BAT adipogenic gene expression between Rdh1-null mice and wild-type mice, including Pparg, Prdm16, Zfp516 and Zfp521, indicated that the phenotype was not driven by brown adipose hyperplasia. Rather, Rdh1 ablation eliminated the increase in BAT atRA that occurs after re-feeding. This disruption of atRA homeostasis increased fatty acid uptake, but attenuated lipolysis in primary brown adipocytes, resulting in increased lipid content and larger lipid droplets. Rdh1 ablation also decreased mitochondrial proteins, including CYCS and UCP1, the mitochondria oxygen consumption rate, and disrupted the mitochondria membrane potential, further reflecting impaired BAT function, resulting in both BAT and white adipose hypertrophy. RNAseq revealed dysregulation of 424 BAT genes in null mice, which segregated predominantly into differences after fasting vs after re-feeding. Exceptions were Rbp4 and Gbp2b, which increased during both dietary conditions. Rbp4 encodes the serum retinol-binding protein-an insulin desensitizer. Gbp2b encodes a GTPase. Because Gbp2b increased several hundred-fold, we overexpressed it in brown adipocytes. This caused a shift to larger lipid droplets, suggesting that GBP2b affects signaling downstream of the ß-adrenergic receptor during basal thermogenesis. Thus, Rdh1-generated atRA in BAT regulates multiple genes that promote BAT adaptation to whole-body energy status, such as fasting and re-feeding. These gene expression changes promote optimum mitochondria function and thermogenesis, limiting adiposity. Attenuation of adiposity and insulin resistance suggests that RDH1 mitigates metabolic syndrome.


Assuntos
Tecido Adiposo Marrom/fisiologia , Adiposidade , Jejum , Hidroxiesteroide Desidrogenases/metabolismo , Tretinoína/metabolismo , Animais , Dieta com Restrição de Gorduras , Ingestão de Alimentos , Metabolismo Energético , Feminino , Deleção de Genes , Intolerância à Glucose/genética , Intolerância à Glucose/metabolismo , Hidroxiesteroide Desidrogenases/genética , Resistência à Insulina , Metabolismo dos Lipídeos , Masculino , Camundongos Endogâmicos C57BL , Termogênese , Vitamina A/metabolismo
9.
Clin Infect Dis ; 69(3): 542-545, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30590481

RESUMO

In a pilot study, heavy water labeling was used to determine hepatitis B surface antigen (HBsAg) turnover rates in chronic hepatitis B (CHB) patients. The mean (standard deviation) half-life of HBsAg in blood was 6.7 (5.5) days, which reflects recent production in the liver and supports strategies aimed at reducing HBsAg production in CHB patients.

10.
Methods Mol Biol ; 1881: 129-151, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30350203

RESUMO

Cell proliferation plays a central role in the pathogenesis of every neoplastic disease as well as many other types of illness. Labeling of newly replicated DNA with deuterium (2H), a nonradioactive isotope of hydrogen, administered to the patients in drinking water (2H2O) is a safe and reliable method to measure the in vivo birth rates of cells. Here, we describe a protocol to measure chronic lymphocytic leukemia B-cell birth/proliferation and death rates over time using this approach.


Assuntos
Linfócitos B/patologia , Desoxirribose/análise , Óxido de Deutério/administração & dosagem , Cromatografia Gasosa-Espectrometria de Massas/métodos , Leucemia Linfocítica Crônica de Células B/patologia , Apoptose , Linfócitos B/metabolismo , Proliferação de Células , DNA/química , DNA/isolamento & purificação , Replicação do DNA , Desoxirribose/química , Óxido de Deutério/química , Cromatografia Gasosa-Espectrometria de Massas/instrumentação , Humanos , Cinética , Leucemia Linfocítica Crônica de Células B/sangue
11.
Arthritis Rheumatol ; 71(3): 431-440, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30277008

RESUMO

OBJECTIVE: Adoptive Treg cell therapy has great potential to treat autoimmune disease. Currently, very little is known about how these cells impact inflamed tissues. This study was undertaken to elucidate how autologous Treg cell therapy influences tissue inflammation in human autoimmune disease. METHODS: We describe a systemic lupus erythematosus (SLE) patient with active skin disease who received adoptive Treg therapy. We comprehensively quantified Treg cells and immune activation in peripheral blood and skin, with data obtained at multiple time points posttreatment. RESULTS: Deuterium tracking of infused Treg cells revealed the transient presence of cells in peripheral blood, accompanied by increased percentages of highly activated Treg cells in diseased skin. Flow cytometric analysis and whole transcriptome RNA sequencing revealed that Treg cell accumulation in skin was associated with a marked attenuation of the interferon-γ pathway and a reciprocal augmentation of the interleukin-17 (IL-17) pathway. This phenomenon was more pronounced in skin relative to peripheral blood. To validate these findings, we investigated Treg cell adoptive transfer of skin inflammation in a murine model and found that it also resulted in a pronounced skewing away from Th1 immunity and toward IL-17 production. CONCLUSION: We report the first case of a patient with SLE treated with autologous adoptive Treg cell therapy. Taken together, our results suggest that this treatment leads to increased activated Treg cells in inflamed skin, with a dynamic shift from Th1 to Th17 responses.


Assuntos
Terapia Baseada em Transplante de Células e Tecidos/métodos , Imunoterapia Adotiva/métodos , Lúpus Eritematoso Sistêmico/terapia , Feminino , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Pessoa de Meia-Idade , Linfócitos T Reguladores/imunologia
12.
J Gerontol A Biol Sci Med Sci ; 74(6): 844-852, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-29897420

RESUMO

BACKGROUND: Direct assessment of skeletal muscle mass in older adults is clinically challenging. Relationships between lean mass and late-life outcomes have been inconsistent. The D3-creatine dilution method provides a direct assessment of muscle mass. METHODS: Muscle mass was assessed by D3-creatine (D3Cr) dilution in 1,382 men (mean age, 84.2 years). Participants completed the Short Physical Performance Battery (SPPB); usual walking speed (6 m); and dual x-ray absorptiometry (DXA) lean mass. Men self-reported mobility limitations (difficulty walking 2-3 blocks or climbing 10 steps); recurrent falls (2+); and serious injurious falls in the subsequent year. Across quartiles of D3Cr muscle mass/body mass, multivariate linear models calculated means for SPPB and gait speed; multivariate logistic models calculated odds ratios for incident mobility limitations or falls. RESULTS: Compared to men in the highest quartile, those in the lowest quartile of D3Cr muscle mass/body mass had slower gait speed (Q1: 1.04 vs Q4: 1.17 m/s); lower SPPB (Q1: 8.4 vs Q4: 10.4 points); greater likelihood of incident serious injurious falls (odds ratio [OR] Q1 vs Q4: 2.49, 95% confidence interval [CI]: 1.37, 4.54); prevalent mobility limitation (OR Q1 vs Q4,: 6.1, 95% CI: 3.7, 10.3) and incident mobility limitation (OR Q1 vs Q4: 2.15 95% CI: 1.42, 3.26); p for trend < .001 for all. Results for incident recurrent falls were in the similar direction (p = .156). DXA lean mass had weaker associations with the outcomes. CONCLUSIONS: Unlike DXA lean mass, low D3Cr muscle mass/body mass is strongly related to physical performance, mobility, and incident injurious falls in older men.

13.
Mol Cell Endocrinol ; 479: 147-158, 2019 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-30342056

RESUMO

OBJECTIVE: Estrogens play a key role in the distribution of adipose tissue and have their action by binding to both estrogen receptors (ER), α and ß. Although ERß has a role in the energy metabolism, limited data of the physiological mechanism and metabolic response involved in the pharmacological activation of ERß is available. METHODS: For clinical relevance, non-ovariectomized female mice were subjected to high fat diet together with pharmacological (DIP - 4-(2-(3,5-dimethylisoxazol-4-yl)-1H-indol-3-yl)phenol) interventions to ERß selective activation. The physiological mechanism was assessed in vivo by magnetic resonance imaging and spectroscopy, and oral glucose and intraperitoneal insulin tolerance test before and after DIP treatment. Liver and adipose tissue metabolic response was measured in HFD + vehicle and HFD + DIP by stable isotope, RNA sequencing and protein content. RESULTS: HFD-fed females treated with DIP had a tissue-specific response towards ERß selective activation. The metabolic profile showed an improved fasting glucose level, insulin sensitivity and reduced liver steatosis. CONCLUSIONS: Our data demonstrate that selective activation of ERß exerts a tissue-specific activity which promotes a beneficial effect on whole body metabolic response to obesity.


Assuntos
Tecido Adiposo/metabolismo , Metabolismo Energético , Receptor beta de Estrogênio/metabolismo , Mitocôndrias/metabolismo , Obesidade/metabolismo , Biogênese de Organelas , Animais , Feminino , Perfilação da Expressão Gênica , Isoxazóis , Ligantes , Lipogênese , Lipólise , Fígado/metabolismo , Camundongos Endogâmicos C57BL
14.
J Lipid Res ; 59(9): 1738-1744, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29910190

RESUMO

The storage of lipids in the form of triglycerides (TGs) and the de novo synthesis (lipogenesis) of fatty acids from nonlipid precursors [de novo lipogenesis (DNL)] are important functions of adipose tissue (AT) that influence whole-body metabolism. Yet, few studies have reported in vivo estimates of adipose lipid kinetics in humans. Fifty-two women with obesity (27 African-American and 25 Caucasian; 29.7 ± 5.5 years; BMI 32.2 ± 2.8 kg/m2; 44.3 ± 4.0% body fat) were enrolled in the study. In vivo synthesis (or replacement) of TGs (fTG) as well as the synthesis of the fatty acid, palmitate [a measure of adipose DNL (fDNL)], were assessed using an 8 week incorporation of deuterium into lipids (glycerol and palmitate moieties of TGs) in subcutaneous abdominal (scABD) and subcutaneous femoral (scFEM) AT. We report, for the first time, significant race differences in both TG synthesis and absolute DNL, with Caucasians having higher fTG and fDNL as compared with African-Americans. The DNL contribution to newly synthesized TG (corrected fDNL) was not different between races. Interestingly, our findings also show that the scFEM adipose depot had higher TG replacement rates relative to the scABD. Finally, the replacement rate of TG (fTG) was negatively correlated with changes in body weight over the 8 week labeling period. Our results provide the first evidence that in vivo TG replacement (synthesis and breakdown) rates differ by ethnicity. In addition, TG turnover varies by depot location in humans, implying an increased capacity for TG storage and higher lipolytic activity in the scFEM AT.


Assuntos
Tecido Adiposo/metabolismo , Grupos de Populações Continentais , Metabolismo dos Lipídeos , Adolescente , Adulto , Peso Corporal , Feminino , Voluntários Saudáveis , Humanos , Cinética , Obesidade/etnologia , Obesidade/metabolismo , Obesidade/patologia , Adulto Jovem
15.
J Cachexia Sarcopenia Muscle ; 9(3): 540-546, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29663711

RESUMO

BACKGROUND: Muscle mass can be measured directly in vivo by isotope dilution, using Creatine-(methyl-d3 ) monohydrate (D3 -Cr) by mouth followed by measurement of the steady-state enrichment of D3 -creatinine (D3 -Crn) in urine. Isotope dilution methods require knowledge of the amount of tracer delivered to the pool of interest. In a subset of human subjects, a small amount of orally administered D3 -Cr 'spills' into urine after absorption and prior to transport into skeletal muscle cells. The objectives were to develop a method to correct for spillage to compare the estimate of muscle mass by D3 -Cr dilution to other assessments of fat-free mass. METHODS: Subjects (19 males, 23-81 years old; 20 females, 20-77 years old) ingested a single dose of 60 mg D3 -Cr and urine was collected prior to and daily for 4 days following the dose. Fasting morning urine samples was assessed for D3 -Cr, total Cr, D3 -Crn, and total Crn concentrations, as well as isotopic enrichments of D3 -Crn, by LC/MS. The 24-h urine collections over 3 days after the dose of D3 -Cr were also performed to determine D3 -Cr spillage. Total body water, fat mass, and fat-free mass were assessed by bioelectrical impedance spectroscopy (BIS). RESULTS: Spillage of D3 -Cr in the urine was greater in women than men. D3 -Crn enrichment and the ratio of Cr/Crn were used in an algorithm to calculate Cr pool size and muscle mass. Specifically, an algorithm was developed for the estimation of spillage based on the relationship between the fasting Cr/Crn ratio and the cumulative proportion of the D3 -Cr dose excreted over 3 days based on 24-h urine collections. Muscle mass corrected using the algorithm based on fasting urine levels correlated (r = 0.9967, P < 0.0001) with that corrected by measuring D3 -Cr dose excreted. Muscle mass measured by D3 -Crn enrichment also correlated (r = 0.8579, P < 0.0001, algorithm corrected) with that measured by 24-h Crn excretion. Muscle mass measured by D3 -Cr dilution method correlated with intracellular water by BIS, whether using spillage corrected by the algorithm (r = 0.9041, P < 0.0001) or measured by 3 day D3 -Cr losses (r = 0.91, P < 0.0001) and similarly correlated with fat-free mass by BIA (r = 0.8857 and 0.8929, P < 0.0001, respectively). CONCLUSIONS: The D3 -Cr dilution method is further validated here as a non-invasive, easy-to-use test for measuring muscle mass. The technical issue of D3 -Cr spillage can be corrected for with a simple algorithm based on fasting spot urine samples. Muscle mass by Cr dilution potentially has broad applications in clinical and research settings.


Assuntos
Creatina/administração & dosagem , Creatina/urina , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Biomarcadores , Creatina/farmacocinética , Creatinina/urina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Tamanho do Órgão , Urinálise , Adulto Jovem
16.
Clin Gastroenterol Hepatol ; 16(12): 1983-1991.e3, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29705265

RESUMO

BACKGROUND & AIMS: Increased de novo lipogenesis (DNL) contributes to the pathogenesis of nonalcoholic steatohepatitis (NASH). Acetyl-CoA carboxylase catalyzes the rate-limiting step in DNL. We evaluated the safety and efficacy of GS-0976, a small molecule inhibitor of acetyl-CoA carboxylase, in patients with NASH. METHODS: In an open-label prospective study, patients with NASH (n = 10) received GS-0976 20 mg orally once daily for 12 weeks. NASH was diagnosed based on a proton density fat fraction estimated by magnetic resonance imaging (MRI-PDFF) ≥10% and liver stiffness by magnetic resonance elastography (MRE) ≥2.88 kPa. The contribution from hepatic DNL to plasma palmitate was measured by 14 days of heavy water labeling before and at the end of treatment. We performed the same labelling protocol in an analysis of healthy volunteers who were not given DNL (controls, n = 10). MRI-PDFF and MRE at baseline, and at weeks 4 and 12 of GS-0976 administration, were measured. We analyzed markers of liver injury and serum markers of fibrosis. RESULTS: The contribution of hepatic DNL to plasma palmitate was significantly greater in patients with NASH compared with controls (43% vs 18%) (P = .003). After 12 weeks administration of GS-0976, the median hepatic DNL was reduced 22% from baseline in patients with NASH (P = .004). Compared with baseline, reductions in MRI-PDFF at week 12 (15.7% vs 9.1% at baseline; P = .006), liver stiffness by MRE (3.4 kPa vs 3.1 kPa at baseline; P = .049), TIMP metallopeptidase inhibitor 1 (275 ng/mL vs 244 ng/mL at baseline; P = .049), and serum level of alanine aminotransferase (101 U/L vs 57 U/L at baseline; P = .23) were consistent with decreased hepatic lipid content and liver injury. At week 12, 7 patients (70%) had a ≥30% decrease in MRI-PDFF. CONCLUSION: In an open-label study, patients with NASH given GS-0976 for 12 weeks had reduced hepatic DNL, steatosis, and markers of liver injury. ClinicalTrials.gov no: NCT02856555.


Assuntos
Acetil-CoA Carboxilase/antagonistas & inibidores , Inibidores Enzimáticos/administração & dosagem , Isobutiratos/administração & dosagem , Lipogênese/efeitos dos fármacos , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/dietoterapia , Hepatopatia Gordurosa não Alcoólica/patologia , Oxazóis/administração & dosagem , Pirimidinas/administração & dosagem , Administração Oral , Adolescente , Adulto , Idoso , Técnicas de Imagem por Elasticidade , Inibidores Enzimáticos/efeitos adversos , Feminino , Humanos , Isobutiratos/efeitos adversos , Fígado/diagnóstico por imagem , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oxazóis/efeitos adversos , Estudos Prospectivos , Pirimidinas/efeitos adversos , Resultado do Tratamento , Adulto Jovem
17.
JCI Insight ; 3(5)2018 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-29515023

RESUMO

Excess lipid accumulation is an early signature of nonalcoholic fatty liver disease (NAFLD). Although liver receptor homolog 1 (LRH-1) (encoded by NR5A2) is suppressed in human NAFLD, evidence linking this phospholipid-bound nuclear receptor to hepatic lipid metabolism is lacking. Here, we report an essential role for LRH-1 in hepatic lipid storage and phospholipid composition based on an acute hepatic KO of LRH-1 in adult mice (LRH-1AAV8-Cre mice). Indeed, LRH-1-deficient hepatocytes exhibited large cytosolic lipid droplets and increased triglycerides (TGs). LRH-1-deficient mice fed high-fat diet displayed macrovesicular steatosis, liver injury, and glucose intolerance, all of which were reversed or improved by expressing wild-type human LRH-1. While hepatic lipid synthesis decreased and lipid export remained unchanged in mutants, elevated circulating free fatty acid helped explain the lipid imbalance in LRH-1AAV8-Cre mice. Lipidomic and genomic analyses revealed that loss of LRH-1 disrupts hepatic phospholipid composition, leading to lowered arachidonoyl (AA) phospholipids due to repression of Elovl5 and Fads2, two critical genes in AA biosynthesis. Our findings reveal a role for the phospholipid sensor LRH-1 in maintaining adequate pools of hepatic AA phospholipids, further supporting the idea that phospholipid diversity is an important contributor to healthy hepatic lipid storage.


Assuntos
Metabolismo dos Lipídeos , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/patologia , Receptores Citoplasmáticos e Nucleares/metabolismo , Acetiltransferases/metabolismo , Fatores Etários , Animais , Ácidos Araquidônicos/metabolismo , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Ácidos Graxos Dessaturases/metabolismo , Hepatócitos/metabolismo , Humanos , Fígado/citologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/etiologia , Fosfolipídeos/metabolismo , Cultura Primária de Células , Receptores Citoplasmáticos e Nucleares/genética , Transgenes/genética
18.
Am J Physiol Endocrinol Metab ; 315(1): E126-E132, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29558206

RESUMO

Fructose feeding increases hepatic de novo lipogenesis (DNL) and is associated with nonalcoholic fatty liver disease. Little is known, however, about individual variation in susceptibility to fructose stimulation of DNL. In this three-period crossover study, 17 healthy male subjects were enrolled to evaluate the within- and between-subject variability of acute fructose feeding on hepatic fractional DNL. During each assessment, [1-13C1]acetate was infused to measure DNL in the fasting state and during fructose feeding. Subjects randomly received a high dose of fructose (10 mg·kg fat-free mass-1·min-1) on two occasions and a low dose (5 mg·kg fat-free mass-1·min-1) on another. Fructose solutions were administered orally every 30 min for 9.5 h. Ten subjects completed all three study periods. DNL was assessed as the fractional contribution of newly synthesized palmitate into very-low-density lipoprotein triglycerides using mass isotopomer distribution analysis. Mean fasting DNL was 5.3 ± 2.8%, with significant within- and between-subject variability. DNL increased dose dependently during fructose feeding to 15 ± 2% for low- and 29 ± 2% for high-dose fructose. The DNL response to high-dose fructose was very reproducible within an individual ( r = 0.93, P < 0.001) and independent of fasting DNL. However, it was variable between individuals and significantly correlated to influx of unlabeled acetyl-CoA ( r = 0.7, P < 0.001). Unlike fasting DNL, fructose-stimulated DNL is a robust and reproducible measure of hepatic lipogenic activity for a given individual and may be a useful indicator of metabolic disease susceptibility and treatment response.


Assuntos
Frutose/farmacologia , Lipogênese/efeitos dos fármacos , Fígado/metabolismo , Acetatos/metabolismo , Acetilcoenzima A/metabolismo , Adulto , Estudos Cross-Over , Relação Dose-Resposta a Droga , Humanos , Lipídeos/sangue , Fígado/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Palmitatos/metabolismo , Triglicerídeos/metabolismo , Adulto Jovem
19.
J Physiol ; 596(11): 2091-2120, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29532476

RESUMO

KEY POINTS: Strategies to enhance the loss of fat while preserving muscle mass during energy restriction are of great importance to prevent sarcopenia in overweight older adults. We show for the first time that the integrated rate of synthesis of numerous individual contractile, cytosolic and mitochondrial skeletal muscle proteins was increased by resistance training (RT) and unaffected by dietary protein intake pattern during energy restriction in free-living, obese older men. We observed a correlation between the synthetic rates of skeletal muscle-derived proteins obtained in serum (creatine kinase M-type, carbonic anhydrase 3) and the synthetic rates of proteins obtained via muscle sampling; and that the synthesis rates of these proteins in serum revealed the stimulatory effects of RT. These results have ramifications for understanding the influence of RT on skeletal muscle and are consistent with the role of RT in maintaining muscle protein synthesis and potentially supporting muscle mass preservation during weight loss. ABSTRACT: We determined how the pattern of protein intake and resistance training (RT) influenced longer-term (2 weeks) integrated myofibrillar protein synthesis (MyoPS) during energy restriction (ER). MyoPS and proteome kinetics were measured during 2 weeks of ER alone and 2 weeks of ER plus RT (ER + RT) in overweight/obese older men. Participants were randomized to consume dietary protein in a balanced (BAL: 25% daily protein per meal × 4 meals) or skewed (SKEW: 7:17:72:4% daily protein per meal) pattern (n = 10 per group). Participants ingested deuterated water during the consecutive 2-week periods, and skeletal muscle biopsies and serum were obtained at the beginning and conclusion of ER and ER + RT. Bulk MyoPS (i.e. synthesis of the myofibrillar protein sub-fraction) and the synthetic rates of numerous individual skeletal muscle proteins were quantified. Bulk MyoPS was not affected by protein distribution during ER or ER + RT (ER: BAL = 1.24 ± 0.31%/day, SKEW = 1.26 ± 0.37%/day; ER + RT: BAL = 1.64 ± 0.48%/day, SKEW = 1.52 ± 0.66%/day) but was ∼26% higher during ER + RT than during ER (P = 0.023). The synthetic rates of 175 of 190 contractile, cytosolic and mitochondrial skeletal muscle proteins, as well as synthesis of muscle-derived proteins measured in serum, creatine kinase M-type (CK-M) and carbonic anhydrase 3 (CA-3), were higher during ER + RT than during ER (P < 0.05). In addition, the synthetic rates of CK-M and CA-3 measured in serum correlated with the synthetic rates of proteins obtained via muscle sampling (P < 0.05). This study provides novel data on the skeletal muscle adaptations to RT and dietary protein distribution.


Assuntos
Dieta Redutora/métodos , Proteínas na Dieta/administração & dosagem , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Obesidade/fisiopatologia , Proteoma/análise , Treinamento de Resistência , Idoso , Índice de Massa Corporal , Metabolismo Energético , Humanos , Masculino , Miofibrilas/metabolismo , Obesidade/terapia
20.
Alcohol Clin Exp Res ; 42(3): 492-499, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29220547

RESUMO

BACKGROUND: Insulin resistance (IR) is associated with hepatitis C virus (HCV), and Latinos are both at risk of IR and are disproportionately affected by HCV. Moderate alcohol consumption improves insulin sensitivity and may modify HCV-associated IR. We investigated the impact of moderate alcohol discontinuation on insulin sensitivity and secretion in Latinos using direct measurements. METHODS: Twenty-five nondiabetic, noncirrhotic Latino adults without (n = 17) or with (n = 8) HCV underwent 3-day metabolic assessment before and after prescription of 6 weeks of moderate alcohol discontinuation. Peripheral IR was measured via steady-state plasma glucose (SSPG) and hepatic IR using endogenous glucose production during a 2-step 240-minute insulin suppression test. Insulin secretion was measured using graded glucose infusion test. RESULTS: Baseline mean age was 46 ± 11 years, 63% male, 29% had HCV, and mean body mass index was 27 ± 4 kg/m2 . Compared to non-HCV, HCV patients had a higher median SSPG (132 vs. 98.8 mg/dl, p = 1.0), hepatic IR (13.5 vs. 11.3, p = 0.24), and insulin secretion rate (ISR-AUC, 1,290 vs. 1,250 pmol/min, p = 0.98). After confirmed alcohol discontinuation, hepatic IR was the only parameter that changed significantly (increased, mean change 2.6 ± 4.8, p = 0.02). Higher baseline alanine aminotransferase (ALT) was also associated with a greater change in hepatic IR (average 4.0 points/ALT doubling, p = 0.004), and HCV was associated with a lesser change (average -7.3 points, p = 0.002), independent of ALT. CONCLUSIONS: Short-term moderate alcohol discontinuation adversely impacted hepatic IR in Latinos which was influenced by level of ALT at baseline independent of etiology. Although reduction in ALT through weight loss and HCV eradication remains a priority in improving IR, the observed nonharmful effect of moderate alcohol use represents a potentially confounding variable that warrants further study.


Assuntos
Abstinência de Álcool , Consumo de Bebidas Alcoólicas/metabolismo , Hepatite C Crônica/metabolismo , Hispano-Americanos , Resistência à Insulina , Secreção de Insulina , Insulina/metabolismo , Adulto , Alanina Transaminase/metabolismo , Aspartato Aminotransferases/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
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