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Chen S, Xi M, Gao F, Li M, Dong T, Geng Z, Liu C, Huang F, Wang J, Li X, Wei P, Miao F. Evaluation of mulberry leaves’ hypoglycemic properties and hypoglycemic mechanisms. Front Pharmacol 2023; 14:1045309. [PMID: 37089923 PMCID: PMC10117911 DOI: 10.3389/fphar.2023.1045309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 03/31/2023] [Indexed: 04/08/2023] Open
Abstract
The effectiveness of herbal medicine in treating diabetes has grown in recent years, but the precise mechanism by which it does so is still unclear to both medical professionals and diabetics. In traditional Chinese medicine, mulberry leaf is used to treat inflammation, colds, and antiviral illnesses. Mulberry leaves are one of the herbs with many medicinal applications, and as mulberry leaf study grows, there is mounting evidence that these leaves also have potent anti-diabetic properties. The direct role of mulberry leaf as a natural remedy in the treatment of diabetes has been proven in several studies and clinical trials. However, because mulberry leaf is a more potent remedy for diabetes, a deeper understanding of how it works is required. The bioactive compounds flavonoids, alkaloids, polysaccharides, polyphenols, volatile oils, sterols, amino acids, and a variety of inorganic trace elements and vitamins, among others, have been found to be abundant in mulberry leaves. Among these compounds, flavonoids, alkaloids, polysaccharides, and polyphenols have a stronger link to diabetes. Of course, trace minerals and vitamins also contribute to blood sugar regulation. Inhibiting alpha glucosidase activity in the intestine, regulating lipid metabolism in the body, protecting pancreatic -cells, lowering insulin resistance, accelerating glucose uptake by target tissues, and improving oxidative stress levels in the body are some of the main therapeutic properties mentioned above. These mechanisms can effectively regulate blood glucose levels. The therapeutic effects of the bioactive compounds found in mulberry leaves on diabetes mellitus and their associated molecular mechanisms are the main topics of this paper’s overview of the state of the art in mulberry leaf research for the treatment of diabetes mellitus.
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Affiliation(s)
- Sikai Chen
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Miaomiao Xi
- The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, China
- Xi’an TANK Medicinal Biology Institute, Xi’an, China
| | - Feng Gao
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Min Li
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - TaiWei Dong
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Zhixin Geng
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Chunyu Liu
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Fengyu Huang
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Jing Wang
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Xingyu Li
- Shaanxi University of Chinese Medicine, Xianyang, China
| | - Peifeng Wei
- Shaanxi University of Chinese Medicine, Xianyang, China
- The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, China
- *Correspondence: Peifeng Wei, ; Feng Miao,
| | - Feng Miao
- The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, China
- *Correspondence: Peifeng Wei, ; Feng Miao,
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Metabolic Flexibility During Exercise in Children with Overweight/Obesity Versus Children who are Lean. Pediatr Exerc Sci 2022; 35:92-98. [PMID: 36370706 DOI: 10.1123/pes.2021-0229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 08/09/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022]
Abstract
PURPOSE This study examined metabolic flexibility with respect to fat metabolism during exercise in children who are lean (n=11; 10.9[0.9] y) and overweight/obese (OW/OB; n=9; 10.3[1.2] y). METHOD Participants were grouped based on body mass index percentiles for age and sex. Groups were mixed in age and sex. Participants completed two 20-minute exercise bouts on a cycle ergometer, separated by a 10-minute rest. Bout 1 consisted of 10 minutes at 50% VO2peak and 10 minutes at 75% VO2peak. Bout 2 was 20 minutes at 50% VO2peak. Absolute fat oxidation rate (FOR), FOR relative to body mass, FOR relative to fat-free mass, and proportional fat use were measured at 10 minutes of bout 1 and 5, 10, 15, and 20 minutes of bout 2. RESULTS Absolute FOR was higher in the OW/OB group (range: 117.8 [55.1]-206.2 [48.3] mg·min-1) than in the lean group (81.1 [32.2]-152.2 [38.2] mg·min-1); however, there were no significant main effects for group or significant interactions for proportional fat use, FOR relative to body mass, or FOR relative to fat-free mass. CONCLUSION Children in this age range who are overweight/obese do not display impaired metabolic flexibility with respect to fat metabolism during exercise.
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Shibib L, Al-Qaisi M, Ahmed A, Miras AD, Nott D, Pelling M, Greenwald SE, Guess N. Reversal and Remission of T2DM - An Update for Practitioners. Vasc Health Risk Manag 2022; 18:417-443. [PMID: 35726218 PMCID: PMC9206440 DOI: 10.2147/vhrm.s345810] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/10/2022] [Indexed: 01/04/2023] Open
Abstract
Over the past 50 years, many countries around the world have faced an unchecked pandemic of obesity and type 2 diabetes (T2DM). As best practice treatment of T2DM has done very little to check its growth, the pandemic of diabesity now threatens to make health-care systems economically more difficult for governments and individuals to manage within their budgets. The conventional view has been that T2DM is irreversible and progressive. However, in 2016, the World Health Organization (WHO) global report on diabetes added for the first time a section on diabetes reversal and acknowledged that it could be achieved through a number of therapeutic approaches. Many studies indicate that diabetes reversal, and possibly even long-term remission, is achievable, belying the conventional view. However, T2DM reversal is not yet a standardized area of practice and some questions remain about long-term outcomes. Diabetes reversal through diet is not articulated or discussed as a first-line target (or even goal) of treatment by any internationally recognized guidelines, which are mostly silent on the topic beyond encouraging lifestyle interventions in general. This review paper examines all the sustainable, practical, and scalable approaches to T2DM reversal, highlighting the evidence base, and serves as an interim update for practitioners looking to fill the practical knowledge gap on this topic in conventional diabetes guidelines.
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Affiliation(s)
- Lina Shibib
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Mo Al-Qaisi
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Ahmed Ahmed
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Alexander D Miras
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - David Nott
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Marc Pelling
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Stephen E Greenwald
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
| | - Nicola Guess
- School of Life Sciences, Westminster University, London, UK
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Averyanova IV. Age-related blood biochemical changes (lipid metabolism) in healthy young and mature men living under the North conditions. Klin Lab Diagn 2021; 66:728-732. [PMID: 35020285 DOI: 10.51620/0869-2084-2021-66-12-728-732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Metabolic disorders (dyslipidemias) are currently crucial since they develop cardiovascular diseases. The work was aimed at studying age dynamics and its correlation with severity of dyslipidemia in basic lipid metabolism variables (in different age groups). MATERIALS AND METHODS Examinees were Caucasians born and permanently residing in Magadan region: 55 mature men and 147 young men (mean ages were 36.8±0.8 and 18.7±0.8 yr, respectively). Blood serum lipid metabolism was examined by colorimetric and photometric method using AU 680 (Beckman Coulter, USA). RESULTS The data of obtained lipidogram showed dependence of rise in all indicators on subjective older age with higher percentage of dyslipidemia and increase in calculated indices reflecting degree of the lipid profile atherogenicity. CONCLUSION Overall, the North study revealed a safer lipid profile in group of younger men, while biochemical picture of older residents demonstrated increased values. Lipid atherogenicity is a very alarming factor in developing cardiovascular diseases, and a predictor of risks for metabolic syndrome.
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Goda Y, Yamanaka D, Nishi H, Masuda M, Kamei H, Kumano M, Ito K, Katsumata M, Yamanouchi K, Kataoka N, Hakuno F, Takahashi SI. Dietary lysine restriction induces lipid accumulation in skeletal muscle through an increase in serum threonine levels in rats. J Biol Chem 2021; 297:101179. [PMID: 34508782 PMCID: PMC8488598 DOI: 10.1016/j.jbc.2021.101179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 08/23/2021] [Accepted: 09/07/2021] [Indexed: 11/02/2022] Open
Abstract
We previously reported that dietary amino acid restriction induces the accumulation of triglycerides (TAG) in the liver of growing rats. However, differences in TAG accumulation in individual cell types or other tissues were not examined. In this study, we show that TAG also accumulates in the muscle and adipose tissues of rats fed a low amino acid (low-AA) diet. In addition, dietary lysine restriction (low-Lys) induces lipid accumulation in muscle and adipose tissues. In adjusting the nitrogen content to that of the control diet, we found that glutamic acid supplementation to the low-AA diet blocked lipid accumulation, but supplementation with the low-Lys diet did not, suggesting that a shortage of nitrogen caused lipids to accumulate in the skeletal muscle in the rats fed a low-AA diet. Serum amino acid measurement revealed that, in rats fed a low-Lys diet, serum lysine levels were decreased, while serum threonine levels were significantly increased compared with the control rats. When the threonine content was restricted in the low-Lys diet, TAG accumulation induced by the low-Lys diet was completely abolished in skeletal muscle. Moreover, in L6 myotubes cultured in medium containing high threonine and low lysine, fatty acid uptake was enhanced compared with that in cells cultured in control medium. These findings suggest that the increased serum threonine in rats fed a low-Lys diet resulted in lipid incorporation into skeletal muscle, leading to the formation of fatty muscle tissue. Collectively, we propose conceptual hypothesis that "amino-acid signal" based on lysine and threonine regulates lipid metabolism.
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Affiliation(s)
- Yuki Goda
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Daisuke Yamanaka
- Department of Veterinary Medical Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroki Nishi
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masato Masuda
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroyasu Kamei
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Mikako Kumano
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Koichi Ito
- Department of Veterinary Medical Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Masaya Katsumata
- School of Veterinary Science, Azabu University, Sagamihara, Kanagawa, Japan
| | - Keitaro Yamanouchi
- Department of Veterinary Medical Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Naoyuki Kataoka
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Fumihiko Hakuno
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
| | - Shin-Ichiro Takahashi
- Departments of Animal Sciences and Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
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Walther CP, Ix JH, Biggs ML, Kizer JR, Navaneethan SD, Djoussé L, Mukamal KJ. Nonesterified Fatty Acids and Kidney Function Decline in Older Adults: Findings From the Cardiovascular Health Study. Am J Kidney Dis 2021; 78:259-267. [PMID: 33548344 DOI: 10.1053/j.ajkd.2020.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/30/2020] [Indexed: 11/11/2022]
Abstract
RATIONALE & OBJECTIVE Circulating nonesterified fatty acids (NEFAs) make up a small portion of circulating lipids but are a metabolically important energy source. Excessive circulating NEFAs may contribute to lipotoxicity in many tissues, including the kidneys. We investigated the relationship between total circulating NEFA concentration and kidney outcomes in older, community-dwelling adults. STUDY DESIGN Prospective cohort study. SETTING & PARTICIPANTS 4,698 participants≥65 years of age in the Cardiovascular Health Study who underwent total fasting serum NEFA concentration measurements in 1992-1993. EXPOSURE Fasting serum NEFA concentration at one time point. OUTCOME Three primary outcomes: estimated glomerular filtration rate (eGFR) decline of≥30%, the composite of eGFR decline≥30% or kidney failure with replacement therapy, and change in eGFR. These outcomes were assessed over 4- and 13-year periods. ANALYTICAL APPROACH Logistic regression for the dichotomous outcomes and mixed effects models for the continuous outcome, with sequential adjustment for baseline covariates. Inverse probability of attrition weighting was implemented to account for informative attrition during the follow-up periods. RESULTS Serum NEFA concentrations were not independently associated with kidney outcomes. In unadjusted and partially adjusted analyses, the highest quartile of serum NEFA concentration (compared with lowest) was associated with a higher risk of≥30% eGFR decline at 4 years and faster rate of decline of eGFR. No associations were evident after adjustment for comorbidities, lipid levels, insulin sensitivity, medications, and vital signs: the odds ratio for the eGFR decline outcome was 1.33 (95% CI, 0.83-2.13), and the difference in eGFR slope in the highest versus lowest quartile of serum NEFA concentration was-0.15 (95% CI, -0.36 to 0.06) mL/min/1.73m2 per year. LIMITATIONS Single NEFA measurements, no measurements of post-glucose load NEFA concentrations or individual NEFA species, no measurement of baseline urine albumin. CONCLUSIONS A single fasting serum NEFA concentration was not independently associated with long-term adverse kidney outcomes in a cohort of older community-living adults.
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Affiliation(s)
- Carl P Walther
- Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, TX.
| | - Joachim H Ix
- Nephrology Section, Veterans Affairs San Diego Healthcare System, and Division of Nephrology-Hypertension, University of California-San Diego, La Jolla, CA
| | - Mary L Biggs
- Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA
| | - Jorge R Kizer
- Cardiology Section, San Francisco Veterans Affairs Healthcare System, and Departments of Medicine, Epidemiology and Biostatistics, University of California-San Francisco, San Francisco, CA
| | - Sankar D Navaneethan
- Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, TX; Section of Nephrology, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX
| | - Luc Djoussé
- Division of Aging, Department of Medicine, Brigham and Women's Hospital, and Boston Veterans Affairs Healthcare System, Boston, MA
| | - Kenneth J Mukamal
- Division of General Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA
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Wang H, Tang C, Gao Z, Huang Y, Zhang B, Wei J, Zhao L, Tong X. Potential Role of Natural Plant Medicine Cyclocarya paliurus in the Treatment of Type 2 Diabetes Mellitus. J Diabetes Res 2021; 2021:1655336. [PMID: 34988228 PMCID: PMC8723876 DOI: 10.1155/2021/1655336] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/11/2021] [Accepted: 11/19/2021] [Indexed: 12/17/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a common chronic metabolic disease that has become increasingly prevalent worldwide. It poses a serious threat to human health and places a considerable burden on global social medical work. To meet the increasing demand for T2DM treatment, research on hypoglycemic drugs is rapidly developing. Cyclocarya paliurus (Batal.) Iljinskaja is a medicinal plant that grows in China. The leaves of C. paliurus contain polysaccharides, triterpenoids, and other chemical components, which have numerous health benefits. Therefore, the use of this plant has attracted extensive attention in the medical community. Over the past few decades, contemporary pharmacological studies on C. paliurus extracts have revealed that it has abundant biological activities. Multiple in vitro and in vivo experiments have shown that C. paliurus extracts are safe and can play a therapeutic role in T2DM through anti-inflammatory and antioxidation activities, and intestinal flora regulation. Its efficacy is closely related to many factors, such as extraction, separation, purification, and modification. Based on summarizing the existing extraction methods, this article further reviews the potential mechanism of C. paliurus extracts in T2DM treatment, and we aimed to provide a reference for future research on natural plant medicine for the prevention and treatment of T2DM and its related complications.
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Affiliation(s)
- Han Wang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, China
| | - Cheng Tang
- Changchun University of Chinese Medicine, China
| | - Zezheng Gao
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, China
| | - Yishan Huang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, China
| | - Boxun Zhang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, China
| | - Jiahua Wei
- Changchun University of Chinese Medicine, China
| | - Linhua Zhao
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, China
| | - Xiaolin Tong
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, China
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Similar rates of fat oxidation during graded submaximal exercise in women of different body composition. PLoS One 2020; 15:e0242551. [PMID: 33206727 PMCID: PMC7673546 DOI: 10.1371/journal.pone.0242551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/04/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Moderate intensity exercise ranging 40-60% of maximum oxygen uptake is advised to promote energy expenditure and fat oxidation in overweight and obese people. Although fat oxidation has been shown to be highly variable among individual, there is still a relative uncertainty regarding exercise prescription for women specifically. This article aimed to determine whether indicators of body composition can be used to narrow the exercise intensity range for exercise prescription in women. METHODS A total of 35 healthy women (age 30.8±9.5 yr) classified according to their BMI in normal weight (NOR; ≤24.9 kg·m2), overweight (OVW; 25-29.9 kg·m2) and obese groups (OBE; ≥30 kg·m2) completed a submaximal graded test (intensities eliciting ~30%, 40%, 50% and 60% of maximum oxygen uptake). Blood lactate, perceived exertion and absolute and relative substrate oxidation for fat (OXFAT) and carbohydrates (OXCHO) were measured at each stage. RESULTS Perceived exertion and blood lactate increased as a function of exercise but did not differ across groups. There were no significant changes in absolute and relative OXFAT across groups, or as a function of exercise intensity. Peak OXFAT occurred at the 40%, 50% and 40% stages for NOR, OVW and OBE groups, respectively, with no significant differences across groups. CONCLUSION We measured no differences, but considerable inter-individual variation, in fat oxidation in women of different body composition. This result is in agreement with previous research based on exercise performed at constant rate and in independent participant groups. Our findings do not support the fat oxidation hypothesis, and further emphasise the perspective that exercise prescription should be individualised and likely be based on considerations other than substrate oxidation.
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Abstract
PURPOSE OF REVIEW Dementia is rapidly growing as sources of morbidity and mortality as the US population ages, but its pathophysiology remains poorly understood. As a result, no disease-modifying treatments currently exist. We review the evidence that nonesterified fatty acids may play a key role in this condition. RECENT FINDINGS Nonesterified fatty acids appear to influence several pathways leading to dementia. In addition to their vascular effects, these moieties cross the blood-brain barrier, where they are toxic to several cell types. They may also influence insulin metabolism in the brain directly and indirectly, and some drugs that lower circulating levels appear to slow cognitive decline and brain atrophy in diabetes. SUMMARY Nonesterified fatty acids may contribute to dementia, much as they do to diabetes and cardiovascular disease. Several therapeutic agents lower circulating levels of nonesterified fatty acids and should be tested for their potential preventive effects on cognitive decline in healthy populations before irreversible neuronal attrition occurs.
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Affiliation(s)
- Kenneth J Mukamal
- Beth Israel Deaconess Medical Center, General Medicine, Brookline, Massachusetts, USA
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Juárez-Rojas JG, Torre-Villalvazo I, Medina-Urrutia AX, Reyes-Barrera J, Sainz-Escárrega VH, Posadas-Romero C, Macías-Cruz A, Jorge-Galarza E. Participation of white adipose tissue dysfunction on circulating HDL cholesterol and HDL particle size in apparently healthy humans. Int J Obes (Lond) 2019; 44:920-928. [PMID: 31792333 DOI: 10.1038/s41366-019-0493-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 10/15/2019] [Accepted: 11/17/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To use the combined presence of the elevated insulin resistance index in adipose tissue (Adipo-IR) and low values of adiponectin as a marker of dysfunctional adipose tissue, and to analyze its possible association with low values of high-density lipoprotein cholesterol (HDL-C) and small size of HDL particles. RESEARCH DESIGN AND METHODS The analysis included 253 subjects with functional adipose tissue and 253 with dysfunctional adipose tissue, considering similar gender, age, and body mass index (BMI). Adipo-IR was considered when index values (free fatty acids × insulin concentrations) were ≥75th percentile. Low levels of adiponectin were considered when concentration in serum was <25th percentile (determined by ELISA). HDL size was estimated by a quantitative validated equation. Small HDL size was considered when values were <25th percentile. RESULTS When comparing subjects with functional adipose tissue with those of dysfunctional adipose tissue, the latter had a higher prevalence of low HDL-C (51.4% vs. 64.0%; p = 0.004) and small HDL (56.9% vs. 67.6%; p = 0.009). Multivariate analysis indicated that independently from other metabolic risk factors, dysfunction of adipose tissue is significantly associated with low HDL-C (OR: 1.624 [CI 95%: 1.100-2.397]) and small HDL (OR: 1.462 [CI 95%: 1.000-2.139]). Adding BMI, waist circumference, and subcutaneous or visceral adipose tissue did not modify the association. CONCLUSIONS Dysfunction of adipose tissue is associated with a 65 and 50% higher probability of having low HDL-C and small HDL. Identification of dysfunctional adipose tissue could be a useful tool in the clinical setting to prevent the cardiometabolic risk independently from adiposity.
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Affiliation(s)
- Juan G Juárez-Rojas
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Ivan Torre-Villalvazo
- Department of Nutrition Physiology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Aida X Medina-Urrutia
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Juan Reyes-Barrera
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Víctor H Sainz-Escárrega
- Department of Cardiothoracic Surgery, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Carlos Posadas-Romero
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Alejandro Macías-Cruz
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Esteban Jorge-Galarza
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico.
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Ortiz R, Kluwe B, Odei J, Echouffo Tcheugui JB, Sims M, Kalyani RR, Bertoni AG, Golden SH, Joseph JJ. The association of morning serum cortisol with glucose metabolism and diabetes: The Jackson Heart Study. Psychoneuroendocrinology 2019; 103:25-32. [PMID: 30623794 PMCID: PMC6450778 DOI: 10.1016/j.psyneuen.2018.12.237] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/23/2018] [Accepted: 12/27/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Serum cortisol levels have been associated with type 2 diabetes (T2D). However, the role of cortisol in glycemia and T2D is not fully elucidated among African Americans (AAs). We hypothesized that among AAs morning serum cortisol would be positively associated with glycemic measures and prevalent T2D. METHODS We examined the cross-sectional association of baseline morning serum cortisol with fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β), and prevalent T2D in the Jackson Heart Study. Linear regression models were used to examine the association of log-transformed cortisol with glycemic traits, stratified by T2D status. Logistic regression was used to examine the association of log-transformed cortisol with prevalent T2D. Models were adjusted for age, sex, education, occupation, systolic blood pressure, waist circumference, physical activity, smoking, beta-blocker/hormone replacement medications and cortisol collection time. RESULTS Among 4,206 AAs (mean age 55 ± 13 years, 64% female), 19% had prevalent T2D. A 100% increase in cortisol among participants without diabetes was associated with 2.7 mg/dL (95% CI: 2.0, 3.3) higher FPG and a 10.0% (95% CI: -14.0, -6.0) lower HOMA-β with no significant association with HbA1c or HOMA-IR. In participants with diabetes, a 100% increase in cortisol was associated with a 23.6 mg/dL (95% CI: 13.6, 33.7) higher FPG and a 0.6% (95% CI: 0.3, 0.9) higher HbA1c. Among all participants, quartile 4 vs. 1 of cortisol was associated with a 1.26-fold (95% CI: 1.75, 2.91) higher odds of prevalent T2D. CONCLUSION Higher morning serum cortisol was associated with higher FPG and lower β-cell function among participants without T2D and higher FPG and HbA1c in participants with diabetes. Among all participants, higher cortisol was associated with higher odds of T2D. These findings support a role for morning serum cortisol in glucose metabolism among AAs.
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Affiliation(s)
- Robin Ortiz
- Departments of Internal Medicine and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
| | | | - James Odei
- Division of Biostatistics, The Ohio State University College of Public Health, Columbus, OH
| | | | - Mario Sims
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS
| | - Rita R. Kalyani
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Alain G. Bertoni
- Division of Public Health Sciences, Wake Forest School of Medicine, Winston Salem, NC
| | - Sherita H. Golden
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Joshua J. Joseph
- Department of Medicine, The Ohio State University College of Medicine, Columbus, OH
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Resorlu M, Karatag O, Toprak CA, Ozturk MO. Neglected areas on thorax computed tomography evaluation in patients with chronic obstructive pulmonary disease: Paravertebral muscles and para-aortic adipose tissue. J Med Imaging Radiat Oncol 2018; 62:487-492. [PMID: 29457360 DOI: 10.1111/1754-9485.12716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 01/20/2018] [Indexed: 01/22/2023]
Abstract
INTRODUCTION This study, investigated the para-aortic adipose tissue cross-sectional area, a novel predictor of cardiovascular diseases and degenerative changes in the paravertebral muscles, in patients with chronic obstructive pulmonary disease (COPD). METHOD One hundred cases diagnosed as COPD and 50 healthy individuals with similar demographic characteristics were evaluated. Para-aortic adipose tissue cross-sectional area (mm2 ), subcutaneous adipose tissue thickness (mm), paravertebral muscle area (mm2 ) and fat deposition in muscle tissue were assessed radiologically. RESULTS Paravertebral muscle mass was lower in the patient group compared to the healthy individuals (471.41 ± 157.71 mm2 and 561.58 + 151.03 mm2 , respectively; P = 0.001). Paravertebral muscle attenuation values were also lower in the patient group, and the grade of deposition increased (P = 0.012 and P = 0.045, respectively). Although subcutaneous adipose tissue thicknesses were similar in the patient and control groups, para-aortic adipose tissue cross-sectional area was higher in the patients with COPD than in the control group (439.34 ± 267.17 mm2 and 333.82 ± 165.23 mm2 , respectively, P = 0.012). The correlation between subcutaneous adipose tissue and para-aortic adipose tissue observed in the healthy group was not present in the subjects with COPD. CONCLUSION Chronic obstructive pulmonary disease causes morphological changes in paravertebral muscles and para-aortic adipose tissue. Degenerative changes in the paravertebral muscles occur secondary to systemic inflammation, comorbidity and drugs used in COPD. Factors such as insulin resistance and steroid use result in an increase in para-aortic adipose tissue mass.
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Affiliation(s)
- Mustafa Resorlu
- Department of Radiology, Faculty of Medicine, Canakkale Onsekiz Mart University, Canakkale, Turkey
| | - Ozan Karatag
- Department of Radiology, Faculty of Medicine, Canakkale Onsekiz Mart University, Canakkale, Turkey
| | - Canan A Toprak
- Department of Radiology, Faculty of Medicine, Canakkale Onsekiz Mart University, Canakkale, Turkey
| | - Muhsin O Ozturk
- Department of Radiology, Faculty of Medicine, Canakkale Onsekiz Mart University, Canakkale, Turkey
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13
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In vivo triglyceride synthesis in subcutaneous adipose tissue of humans correlates with plasma HDL parameters. Atherosclerosis 2016; 251:147-152. [PMID: 27323227 DOI: 10.1016/j.atherosclerosis.2016.06.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUNDS AND AIMS Low concentrations of plasma HDL-C are associated with the development of atherosclerotic cardiovascular diseases and type 2 diabetes. Here we aimed to explore the relationship between the in vivo fractional synthesis of triglycerides (fTG) in subcutaneous (s.q.) abdominal adipose tissue (AT), HDL-C concentrations and HDL particle size composition in non-diabetic humans. METHODS The fTG in s.q. abdominal AT was measured in 16 non-diabetic volunteers (7 women, 9 men; Age: 49 ± 20 years; BMI: 31 ± 5 kg/m; Fasting Plasma Glucose: 90 ± 10 mg/dl) after (2)H2O labeling. HDL-C concentration and subclasses, large (L-HDL), intermediate (I-HDL) and small (S-HDL) were measured. RESULTS Linear regression analyses demonstrated significant associations of fTG with plasma concentration of HDL-C (r = 0.625,p = 0.009) and percent contribution of L-HDL (r = 0.798,p < 0.001), I-HDL (r = -0.765,p < 0.001) and S-HDL (r = -0.629, p = 0.009). When analyses were performed by gender, the associations remained significant in women (HDL-C: r = 0.822,p = 0.023; L-HDL: r = 0.892,p = 0.007; I-HDL: r = -0.927,p = 0.003) but not men. CONCLUSIONS Our study demonstrated an in vivo association between subcutaneous abdominal adipose tissue lipid dynamics and HDL parameters in humans, but this was true for women not men. Positive association with L-HDL and negative with I-HDL suggest that subcutaneous abdominal adipose tissue lipid dynamics may play an important role in production of mature functional HDL particles. Further studies evaluating the mechanism responsible for these associations and the observed gender differences are important and warranted to identify potential novel targets of intervention to increase the production of atheroprotective subclasses of HDL-Cs and thus decreasing the risks of development of atherosclerotic conditions.
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14
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Sarafian D, Schutz Y, Montani JP, Dulloo AG, Miles-Chan JL. Sex difference in substrate oxidation during low-intensity isometric exercise in young adults. Appl Physiol Nutr Metab 2016; 41:977-84. [PMID: 27540628 DOI: 10.1139/apnm-2016-0127] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Low-intensity physical activity is increasingly promoted as an alternative to sedentary behavior. However, much research to date has focused on moderate- to vigorous-intensity physical activity, and in particular dynamic work, with the effect of low-intensity isometric exercise (<4 METs) on substrate utilization yet to be explored. Here we investigate the effects of such exercise on respiratory quotient (RQ) and determine the extent of intra- and inter-individual variability in response. Energy expenditure, RQ, and substrate oxidation were measured by ventilated-hood indirect calorimetry at rest and in response to standardized, intermittent, low-level isometric leg-press exercises at 5 loads (+5, +10, +15, +20, +25 kg) in 26 healthy, young adults. Nine participants repeated the experiment on 3 separate days to assess within-subject, between-day variability. There was no significant difference in energy cost and heart rate responses to low-intensity isometric exercise (<2 METs) between men and women. However, a sex difference was apparent in terms of substrate oxidation - with men increasing both fat and carbohydrate oxidation, and women only increasing fat oxidation while maintaining carbohydrate oxidation at baseline, resting levels. This sex difference was repeatable and persisted when substrate oxidation was adjusted for differences in body weight or body composition. Individual variability in RQ was relatively low, with both intra- and inter-individual coefficients of variation in the range of 3%-6% in both sexes. These results suggest that women preferentially increase fat oxidation during low-level isometric exercise. Whether such physical activity could be incorporated into treatment/prevention strategies aimed at optimizing fat oxidation in women warrants further investigation.
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Affiliation(s)
- Delphine Sarafian
- Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.,Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
| | - Yves Schutz
- Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.,Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
| | - Jean-Pierre Montani
- Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.,Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
| | - Abdul G Dulloo
- Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.,Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
| | - Jennifer L Miles-Chan
- Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland.,Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
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Hioki M, Kanehira N, Koike T, Saito A, Takahashi H, Shimaoka K, Sakakibara H, Oshida Y, Akima H. Associations of intramyocellular lipid in vastus lateralis and biceps femoris with blood free fatty acid and muscle strength differ between young and elderly adults. Clin Physiol Funct Imaging 2015; 36:457-463. [DOI: 10.1111/cpf.12250] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/04/2015] [Indexed: 01/07/2023]
Affiliation(s)
- Maya Hioki
- Graduate School of Medicine; Nagoya University; Showa-ku Nagoya Aichi Japan
| | - Nana Kanehira
- School of Health and Nutrition; Tokaigakuen University; Tenpaku Nagoya Aichi Japan
| | - Teruhiko Koike
- Research Center of Health, Physical Fitness & Sports; Nagoya University; Chikusa-ku Nagoya Aichi Japan
| | - Akira Saito
- Graduate School of Education and Human Development; Nagoya University; Chikusa-ku Nagoya Aichi Japan
- Japan Society for the Promotion of Science; Tokyo Japan
| | | | - Kiyoshi Shimaoka
- School of Sport and Health Science; Tokaigakuen University; Ukigai Miyoshi Aichi Japan
| | | | - Yoshiharu Oshida
- Research Center of Health, Physical Fitness & Sports; Nagoya University; Chikusa-ku Nagoya Aichi Japan
| | - Hiroshi Akima
- Research Center of Health, Physical Fitness & Sports; Nagoya University; Chikusa-ku Nagoya Aichi Japan
- Graduate School of Education and Human Development; Nagoya University; Chikusa-ku Nagoya Aichi Japan
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16
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Increased pyruvate dehydrogenase kinase expression in cultured myotubes from obese and diabetic individuals. Eur J Nutr 2014; 54:1033-43. [DOI: 10.1007/s00394-014-0780-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
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17
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Kelsey MM, Forster JE, Van Pelt RE, Reusch JEB, Nadeau KJ. Adipose tissue insulin resistance in adolescents with and without type 2 diabetes. Pediatr Obes 2014; 9:373-80. [PMID: 23861170 PMCID: PMC4285336 DOI: 10.1111/j.2047-6310.2013.00189.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/17/2013] [Accepted: 05/24/2013] [Indexed: 12/30/2022]
Abstract
BACKGROUND The incidence of type 2 diabetes mellitus (T2D) is increasing in youth, yet little is known about the underlying pathophysiology. Decreased insulin suppression of lipolysis and elevated non-esterified free fatty acid (NEFA) concentrations are known to be associated with insulin resistance and T2D in adults, but less is known about the relationship in adolescents. OBJECTIVES This study aimed to assess adipose tissue insulin resistance (IR; insulin suppression of lipolysis) and its metabolic correlates in lean, obese and T2D adolescents. METHODS Forty-seven lean, obese and T2D youth underwent hyperinsulinaemic (80 mU*m(-2) *min(-1)) euglycaemic clamps. NEFAs were measured at baseline and during steady state. Insulin-mediated suppression of lipolysis (%NEFA suppression from baseline) was calculated, and metabolic risk factors were assessed by %NEFA suppression tertile. RESULTS There was expected variability in %NEFA suppression within obese and T2D youth, but a subset had significantly reduced suppression of lipolysis. NEFA suppression tertile was significantly inversely associated with fasting triglycerides (P = 0.0001), log alanine aminotransferase (ALT; P = 0.02) and low-density lipoprotein cholesterol (P = 0.0002). CONCLUSIONS Marked adipose tissue IR occurs in some obese and T2D adolescents, which may result in release of triglycerides into the circulation and liver deposition of fatty acids, as evidenced by higher ALT in poor NEFA suppressors.
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Affiliation(s)
- Megan M Kelsey
- University of Colorado Anschutz Medical Campus, Department of Pediatrics,Children’s Hospital Colorado
| | - Jeri E Forster
- University of Colorado Anschutz Medical Campus, Department of Biostatistics and Informatics, Colorado School of Public Health
| | | | - Jane EB Reusch
- University of Colorado Anschutz Medical Campus, Department of Medicine
| | - Kristen J Nadeau
- University of Colorado Anschutz Medical Campus, Department of Pediatrics,Children’s Hospital Colorado
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18
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Rodriguez S, Ellis JM, Wolfgang MJ. Chemical-genetic induction of Malonyl-CoA decarboxylase in skeletal muscle. BMC BIOCHEMISTRY 2014; 15:20. [PMID: 25152047 PMCID: PMC4236586 DOI: 10.1186/1471-2091-15-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 08/13/2014] [Indexed: 01/02/2023]
Abstract
Background Defects in skeletal muscle fatty acid oxidation have been implicated in the etiology of insulin resistance. Malonyl-CoA decarboxylase (MCD) has been a target of investigation because it reduces the concentration of malonyl-CoA, a metabolite that inhibits fatty acid oxidation. The in vivo role of muscle MCD expression in the development of insulin resistance remains unclear. Results To determine the role of MCD in skeletal muscle of diet induced obese and insulin resistant mouse models we generated mice expressing a muscle specific transgene for MCD (Tg-fMCDSkel) stabilized posttranslationally by the small molecule, Shield-1. Tg-fMCDSkel and control mice were placed on either a high fat or low fat diet for 3.5 months. Obese and glucose intolerant as well as lean control Tg-fMCDSkel and nontransgenic control mice were treated with Shield-1 and changes in their body weight and insulin sensitivity were determined upon induction of MCD. Inducing MCD activity >5-fold in skeletal muscle over two weeks did not alter body weight or glucose intolerance of obese mice. MCD induction further potentiated the defects in insulin signaling of obese mice. In addition, key enzymes in fatty acid oxidation were suppressed following MCD induction. Conclusion Acute induction of MCD in the skeletal muscle of obese and glucose intolerant mice did not improve body weight and decreased insulin sensitivity compared to obese nontransgenic controls. Induction of MCD in skeletal muscle resulted in a suppression of mitochondrial oxidative genes suggesting a redundant and metabolite driven regulation of gene expression.
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Affiliation(s)
| | | | - Michael J Wolfgang
- Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, 725 N, Wolfe St,, 475 Rangos Building, Baltimore, Maryland 21205, USA.
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19
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Mizgier ML, Casas M, Contreras-Ferrat A, Llanos P, Galgani JE. Potential role of skeletal muscle glucose metabolism on the regulation of insulin secretion. Obes Rev 2014; 15:587-97. [PMID: 24618283 DOI: 10.1111/obr.12166] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/31/2014] [Accepted: 02/09/2014] [Indexed: 01/03/2023]
Abstract
Pancreatic beta cells sense glucose flux and release as much insulin as required in order to maintain glycaemia within a narrow range. Insulin secretion is regulated by many factors including glucose, incretins, and sympathetic and parasympathetic tones among other physiological factors. To identify the mechanisms linking obesity-related insulin resistance with impaired insulin secretion represents a central challenge. Recently, it has been argued that a crosstalk between skeletal muscle and the pancreas may regulate insulin secretion. Considering that skeletal muscle is the largest organ in non-obese subjects and a major site of insulin- and exercise-stimulated glucose disposal, it appears plausible that muscle might interact with the pancreas and modulate insulin secretion for appropriate peripheral intracellular glucose utilization. There is growing evidence that muscle can secrete so-called myokines that can have auto/para/endocrine actions. Although it is unclear in which direction they act, interleukin-6 seems to be a possible muscle-derived candidate protein mediating such inter-organ communication. We herein review some of the putative skeletal muscle-derived factors mediating this interaction. In addition, the evidence coming from in vitro, animal and human studies that support such inter-organ crosstalk is thoroughly discussed.
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Affiliation(s)
- M L Mizgier
- Departmento de Nutrición, Diabetes y Metabolismo, Pontificia Universidad Católica de Chile, Santiago, Chile
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20
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Dennedy MC, Vidal-Puig A. Review Article: An Adipocentric View of the Metabolic Syndrome and Cardiovascular Disease. CURRENT CARDIOVASCULAR RISK REPORTS 2014. [DOI: 10.1007/s12170-014-0379-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Bernard JJ, Lou YR, Peng QY, Li T, Vakil PR, Ding N, Laskin JD, Dong Z, Conney AH, Lu YP. Parametrial fat tissue from high fat diet-treated SKH-1 mice stimulates transformation of mouse epidermal JB6 cells. ACTA ACUST UNITED AC 2014; 5:2157-2518. [PMID: 25821644 DOI: 10.4172/2157-2518.1000183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Our previous studies indicated that decreasing visceral adipose tissue by surgical removal of the parametrial fat pads inhibited UVB-induced carcinogenesis in SKH-1 mice fed a high fat diet (HFD), but not a low fat diet (LFD) indicating that the parametrial fat tissue from mice fed a HFD played a role in skin carcinogenesis. OBJECTIVE In the present study, we sought to investigate how a HFD may influence the intrinsic properties of the parametrial fat tissue to influence UVB-induced skin tumor formation. METHODS AND RESULTS Immunohistochemical staining, adipokine array, and flow cytometry showed that parametrial fat tissue from mice fed a HFD had a higher density of macrophage-fused dead adipocytes (crown-like structures), more adipokines, and stimulated the production of more reactive oxygen species compared with parametrial fat tissue from mice fed a LFD. These differences between parametrial fat tissue from mice fed a HFD and LFD were associated with their effect on the in vitro transformation of mouse epidermal JB6 cells. Our results indicated that fat tissue filtrate (an aqueous filtrate made from the parametrial fat pad) from mice fed a HFD enhanced the conversion of JB6 cells from an epithelial-like morphology to cells with a fibroblast-like morphology to a greater extent than fat tissue filtrate from mice fed a LFD. Studies indicated that the fibroblast-like cells had decreased levels of E-cadherin, increased levels of Twist as assayed by western blot. Fat tissue filtrate made from the parametrial fat tissue of mice fed a HFD had 160% more transforming activity than that from mice fed a LFD and formed malignant mesenchymal tumors in vivo. CONCLUSION These studies provide the first in vitro demonstration of a parametrial fat tissue-induced transformation of an epidermal cell.
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Affiliation(s)
- Jamie J Bernard
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - You-Rong Lou
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Qing-Yun Peng
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Tao Li
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Priyal R Vakil
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Ning Ding
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Jeffrey D Laskin
- Department of Environmental and Occupational Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School
| | - Zigang Dong
- The Hormel Institute, University of Minnesota, Austin, MN 55912
| | - Allan H Conney
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Yao-Ping Lu
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
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Hoppeler H, Baum O, Lurman G, Mueller M. Molecular mechanisms of muscle plasticity with exercise. Compr Physiol 2013; 1:1383-412. [PMID: 23733647 DOI: 10.1002/cphy.c100042] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The skeletal muscle phenotype is subject to considerable malleability depending on use. Low-intensity endurance type exercise leads to qualitative changes of muscle tissue characterized mainly by an increase in structures supporting oxygen delivery and consumption. High-load strength-type exercise leads to growth of muscle fibers dominated by an increase in contractile proteins. In low-intensity exercise, stress-induced signaling leads to transcriptional upregulation of a multitude of genes with Ca(2+) signaling and the energy status of the muscle cells sensed through AMPK being major input determinants. Several parallel signaling pathways converge on the transcriptional co-activator PGC-1α, perceived as being the coordinator of much of the transcriptional and posttranscriptional processes. High-load training is dominated by a translational upregulation controlled by mTOR mainly influenced by an insulin/growth factor-dependent signaling cascade as well as mechanical and nutritional cues. Exercise-induced muscle growth is further supported by DNA recruitment through activation and incorporation of satellite cells. Crucial nodes of strength and endurance exercise signaling networks are shared making these training modes interdependent. Robustness of exercise-related signaling is the consequence of signaling being multiple parallel with feed-back and feed-forward control over single and multiple signaling levels. We currently have a good descriptive understanding of the molecular mechanisms controlling muscle phenotypic plasticity. We lack understanding of the precise interactions among partners of signaling networks and accordingly models to predict signaling outcome of entire networks. A major current challenge is to verify and apply available knowledge gained in model systems to predict human phenotypic plasticity.
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Affiliation(s)
- Hans Hoppeler
- Institute of Anatomy, University of Bern, Bern, Switzerland.
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Mor A, Tabone L, Omotosho P, Torquati A. Improved insulin sensitivity after gastric bypass correlates with decreased total body fat, but not with changes in free fatty acids. Surg Endosc 2013; 28:1489-1493. [PMID: 24317547 DOI: 10.1007/s00464-013-3338-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/12/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND Increased plasma free fatty acids (FFAs) are considered one of the key elements in the pathogenesis of insulin resistance (IR) and type 2 diabetes (T2DM). We hypothesize that, in diabetic patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB), a postoperative decrease in FFA will correlate with improved insulin sensitivity (Si). METHODS A total of 30 obese [body mass index ((BMI) >35 kg/m(2)] patients with a diagnosis of T2DM were studied preoperatively and 12 months after LRYGB in a prospective cohort study. Collected data included intravenous glucose tolerance test (IVGTT), total body composition by dual-energy X-ray absorptiometry and plasma levels of FFA. Si analysis from the IVGTT was estimated from minimal model analysis. Pre- and postoperative variables were compared using a paired sample t test. Relationships between changes in variables were determined with Pearson's correlation test. RESULTS Twelve months after LRYGB the study population showed a significant decrease in BMI (p = 0.001), FFA (p = 0.03), and total body fat (p = 0.03), with an increase in Si (p = 0.001). Postoperative changes in Si significantly correlated (Pearson's r = -0.53, p = 0.01) with change in total body fat, but not with changes in plasma FFA (Pearson's r = -0.22, p = 0.31). CONCLUSIONS Our study challenges the notion that IR is mediated to a significant degree by changes in plasma FFA concentration. Instead, changes in adiposity and consequently changes in adipokine release can be the key players in determining remission of T2DM after LRYGB.
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Cornall LM, Mathai ML, Hryciw DH, McAinch AJ. Is GPR119 agonism an appropriate treatment modality for the safe amelioration of metabolic diseases? Expert Opin Investig Drugs 2013; 22:487-98. [DOI: 10.1517/13543784.2013.775245] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Surgical removal of the parametrial fat pads stimulates apoptosis and inhibits UVB-induced carcinogenesis in mice fed a high-fat diet. Proc Natl Acad Sci U S A 2012; 109:9065-70. [PMID: 22615388 DOI: 10.1073/pnas.1205810109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Removal of the parametrial fat pads (partial lipectomy) from female SKH-1 mice fed a high-fat diet inhibited UVB-induced carcinogenesis, but this was not observed in mice fed a low-fat chow diet. Partial lipectomy in high-fat-fed mice decreased the number of keratoacanthomas and squamous cell carcinomas per mouse by 76 and 79%, respectively, compared with sham-operated control mice irradiated with UVB for 33 wk. Immunohistochemical analysis indicated that partial lipectomy increased caspase 3 (active form) positive cells by 48% in precancerous epidermis away from tumors, by 68% in keratoacanthomas, and by 224% in squamous cell carcinomas compared with sham-operated control mice. In addition, partial lipectomy decreased cell proliferation away from tumors and in tumors. RT-PCR analysis for adipokines revealed that mRNAs for TIMP1, MCP1, and SerpinE1 (proinflammatory/antiapoptotic cytokines) in the parametrial fat pads of sham-operated control mice were 54- to 83-fold higher than levels in compensatory fat that returned after surgery in partially lipectomized mice at the end of the tumor study. Feeding mice high-fat diets for 2 wk increased levels of TIMP1 and other adipokines in serum and epidermis, and these increases were inhibited by removal of the parametrial fat pads. Our results are a unique demonstration that surgical removal of a specific tissue fat results in inhibition of carcinogenesis in obese mice. This inhibition was associated with an increase in apoptosis and a decrease in proliferation in tumors and in precancerous areas away from tumors.
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Goodpaster BH, Delany JP, Otto AD, Kuller L, Vockley J, South-Paul JE, Thomas SB, Brown J, McTigue K, Hames KC, Lang W, Jakicic JM. Effects of diet and physical activity interventions on weight loss and cardiometabolic risk factors in severely obese adults: a randomized trial. JAMA 2010; 304:1795-802. [PMID: 20935337 PMCID: PMC3082279 DOI: 10.1001/jama.2010.1505] [Citation(s) in RCA: 346] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
CONTEXT The prevalence of severe obesity is increasing markedly, as is prevalence of comorbid conditions such as hypertension and type 2 diabetes mellitus; however, apart from bariatric surgery and pharmacotherapy, few clinical trials have evaluated the treatment of severe obesity. OBJECTIVE To determine the efficacy of a weight loss and physical activity intervention on the adverse health risks of severe obesity. DESIGN, SETTING, AND PARTICIPANTS Single-blind randomized trial conducted from February 2007 through April 2010 at the University of Pittsburgh. Participants were 130 (37% African American) severely obese (class II or III) adult participants without diabetes recruited from the community. INTERVENTIONS One-year intensive lifestyle intervention consisting of diet and physical activity. One group (initial physical activity) was randomized to diet and physical activity for the entire 12 months; the other group (delayed physical activity) had the identical dietary intervention but with physical activity delayed for 6 months. MAIN OUTCOME MEASURES Changes in weight. Secondary outcomes were additional components comprising cardiometabolic risk, including waist circumference, abdominal adipose tissue, and hepatic fat content. RESULTS Of 130 participants randomized, 101 (78%) completed the 12-month follow-up assessments. Although both intervention groups lost a significant amount of weight at 6 months, the initial-activity group lost significantly more weight in the first 6 months compared with the delayed-activity group (10.9 kg [95% confidence interval {CI}, 9.1-12.7] vs 8.2 kg [95% CI, 6.4-9.9], P = .02 for group × time interaction). Weight loss at 12 months, however, was similar in the 2 groups (12.1 kg [95% CI, 10.0-14.2] vs 9.9 kg [95% CI, 8.0-11.7], P = .25 for group × time interaction). Waist circumference, visceral abdominal fat, hepatic fat content, blood pressure, and insulin resistance were all reduced in both groups. The addition of physical activity promoted greater reductions in waist circumference and hepatic fat content. CONCLUSION Among patients with severe obesity, a lifestyle intervention involving diet combined with initial or delayed initiation of physical activity resulted in clinically significant weight loss and favorable changes in cardiometabolic risk factors. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00712127.
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Affiliation(s)
- Bret H Goodpaster
- Division of Endocrinology and Metabolism, Department of Medicine, School of Medicine, University of Pittsburgh, MUH N810, 3459 Fifth Ave, Pittsburgh, PA 15213, USA.
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Albu JB, Heilbronn LK, Kelley DE, Smith SR, Azuma K, Berk ES, Pi-Sunyer FX, Ravussin E. Metabolic changes following a 1-year diet and exercise intervention in patients with type 2 diabetes. Diabetes 2010; 59:627-33. [PMID: 20028945 PMCID: PMC2828653 DOI: 10.2337/db09-1239] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To characterize the relationships among long-term improvements in peripheral insulin sensitivity (glucose disposal rate [GDR]), fasting glucose, and free fatty acids (FFAs) and concomitant changes in weight and adipose tissue mass and distribution induced by lifestyle intervention in obese individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS We measured GDR, fasting glucose, and FFAs during a euglycemic clamp and adipose tissue mass and distribution, organ fat, and adipocyte size by dual-energy X-ray absorptiometry, CT scan, and adipose tissue biopsy in 26 men and 32 women in the Look-AHEAD trial before and after 1 year of diet and exercise aimed at weight loss. RESULTS Weight and fasting glucose decreased significantly (P < 0.0001) and significantly more in men than in women (-12 vs. -8% and -16 vs. -7%, respectively; P < 0.05), while FFAs during hyperinsulinemia decreased and GDR increased significantly (P < 0.00001) and similarly in both sexes (-53 vs. -41% and 63 vs. 43%; P = NS). Men achieved a more favorable fat distribution by losing more from upper compared with lower and from deeper compared with superficial adipose tissue depots (P < 0.01). Decreases in weight and adipose tissue mass predicted improvements in GDR but not in fasting glucose or fasting FFAs; however, decreases in FFAs during hyperinsulinemia significantly determined GDR improvements. Hepatic fat was the only regional fat measure whose change contributed independently to changes in metabolic variables. CONCLUSIONS Patients with type 2 diabetes undergoing a 1-year lifestyle intervention had significant improvements in GDR, fasting glucose, FFAs and adipose tissue distribution. However, changes in overall weight (adipose tissue mass) and hepatic fat were the most important determinants of metabolic improvements.
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Affiliation(s)
- Jeanine B Albu
- Department of Medicine, St. Luke's-Roosevelt Hospital Center, Columbia University, New York, New York, USA.
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Gastaldelli A, Casolaro A, Ciociaro D, Frascerra S, Nannipieri M, Buzzigoli E, Ferrannini E. Decreased whole body lipolysis as a mechanism of the lipid-lowering effect of pioglitazone in type 2 diabetic patients. Am J Physiol Endocrinol Metab 2009; 297:E225-30. [PMID: 19417125 DOI: 10.1152/ajpendo.90960.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pioglitazone has been shown to reduce fasting triglyceride levels. The mechanisms of this effect have not been fully elucidated, but decreased lipolysis may contribute to blunt the hypertriglyceridemic response to a meal. To test this hypothesis, we studied 27 type 2 diabetes mellitus (T2DM) patients and 7 sex-, age-, and body mass index-matched nondiabetic controls. Patients were randomized to pioglitazone (45 mg/day) or placebo for 16 wk. Whole body lipolysis was measured [as the [(2)H(5)]glycerol rate of appearance (R(a))] in the fasting state and for 6 h following a mixed meal. Compared with controls, T2DM had higher postprandial profiles of plasma triglycerides, free fatty acid (FFA), and beta-hydroxybutyrate, and a decreased suppression of glycerol R(a) (P < 0.04) despite higher insulin levels [268 (156) vs. 190 (123) pmol/l, median (interquartile range)]. Following pioglitazone, triglycerides and FFA were reduced (P = 0.05 and P < 0.04, respectively), and glycerol R(a) was more suppressed [-40 (137) vs. +7 (202) mumol/min of placebo, P < 0.05] despite a greater fall in insulin [-85 (176) vs. -20 (58) pmol/l, P = 0.05]. We conclude that, in well-controlled T2DM patients, whole body lipolysis is insulin resistant, and pioglitazone improves the insulin sensitivity of lipolysis.
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Affiliation(s)
- Amalia Gastaldelli
- Department of Internal Medicine, University of Pisa, Via Roma, 67, 56100 Pisa, Italy
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Sparks LM, Ukropcova B, Smith J, Pasarica M, Hymel D, Xie H, Bray GA, Miles JM, Smith SR. Relation of adipose tissue to metabolic flexibility. Diabetes Res Clin Pract 2009; 83:32-43. [PMID: 19038471 PMCID: PMC2749984 DOI: 10.1016/j.diabres.2008.09.052] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 09/18/2008] [Accepted: 09/30/2008] [Indexed: 12/25/2022]
Abstract
Metabolic flexibility is the capacity for skeletal muscle to shift reliance between lipids and glucose during fasting or in response to insulin. We hypothesized that body fat, adipose tissue characteristics, e.g. larger adipocytes, presence of inflammatory gene markers and impaired suppression of non-esterified fatty acids (NEFAs) during insulin infusion might be related to metabolic flexibility. We measured changes in respiratory quotient (DeltaRQ) before and during euglycemic-hyperinsulinemic clamp in healthy young males. Body fat by DXA, laboratory measurements, abdominal subcutaneous adipose tissue biopsies and fat cell size (FCS) were obtained after an overnight fast. Gene expression for 17 adipose tissue genes related to lipid synthesis, uptake, oxidation and storage, lipolysis and inflammation were measured. Reduced metabolic flexibility was associated with higher body fat, larger FCS and impaired insulin suppression of NEFAs. Metabolic flexibility was associated with higher serum adiponectin levels. Lower adipose tissue gene expression for inflammation markers was associated with greater NEFA suppression by insulin and metabolic flexibility. Combined, these results indicate that body fat, larger adipocytes, failure of insulin to suppress NEFAs, decreased adiponectin levels and inflammation markers in adipose tissue are associated with decreased insulin-stimulated glucose uptake and oxidation, which is an important component of reduced metabolic flexibility.
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Affiliation(s)
- Lauren M Sparks
- Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
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30
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Riddell MC, Jamnik VK, Iscoe KE, Timmons BW, Gledhill N. Fat oxidation rate and the exercise intensity that elicits maximal fat oxidation decreases with pubertal status in young male subjects. J Appl Physiol (1985) 2008; 105:742-8. [PMID: 18535137 DOI: 10.1152/japplphysiol.01256.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The range of exercise intensities that elicit high fat oxidation rates (FOR) in youth and the influence of pubertal status on peak FOR are unknown. In a longitudinal design, we compared FOR over a range of exercise intensities in a small cohort of developing prepubertal male subjects. Five boys all at Tanner stage 1 (ages 11-12 yr) and nine men (ages 20-26 yr) underwent an incremental cycle ergometry test to volitional exhaustion. FOR curves were determined from indirect calorimetry during the final 30 s of each increment. The same protocol was duplicated annually in the boys as they progressed through puberty. The peak FOR was considerably higher (P<0.05) in boys at Tanner 1 (8.6+/-1.5 mg.kg lean body mass(-1).min(-1)) (mean+/-SD) compared with men (4.2+/-1.1 mg.kg lean body mass(-1).min(-1)). FOR dropped as boys developed through puberty (Tanner 2/3 peak rate=7.6+/-0.6 mg.kg lean body mass(-1).min(-1); Tanner 4 peak rate=5.4+/-1.8 mg.kg lean body mass(-1).min(-1), main effect of Tanner stage; P<0.05) to the levels found in men (not significant). The exercise intensity that elicited peak FOR was higher in the boys at Tanner 1 [56+/-6% peak aerobic power (VO2 peak)] than in men (31+/-4% VO2 peak) (P<0.001). This value tended to decrease by Tanner stage 4 (45+/-10% VO2 peak, main effect of Tanner stage; P=0.06). We conclude that, compared with men, prepubertal boys have higher relative FOR throughout a wide range of exercise intensities and that FOR drops as boys develop through puberty.
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Affiliation(s)
- M C Riddell
- School of Kinesiology and Health Science, Faculty of Health, York University, 4700 Keele St., Toronto, ON, Canada M3J 1P3.
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31
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Galgani JE, Heilbronn LK, Azuma K, Kelley DE, Albu JB, Pi-Sunyer X, Smith SR, Ravussin E. Metabolic flexibility in response to glucose is not impaired in people with type 2 diabetes after controlling for glucose disposal rate. Diabetes 2008; 57:841-5. [PMID: 18285553 PMCID: PMC2756651 DOI: 10.2337/db08-0043] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Compared with nondiabetic subjects, type 2 diabetic subjects are metabolically inflexible with impaired fasting fat oxidation and impaired carbohydrate oxidation during a hyperinsulinemic clamp. We hypothesized that impaired insulin-stimulated glucose oxidation is a consequence of the lower cellular glucose uptake rate in type 2 diabetes. Therefore, we compared metabolic flexibility to glucose adjusted for glucose disposal rate in nondiabetic versus type 2 diabetic subjects and in the latter group after 1 year of lifestyle intervention (the Look AHEAD [Action For Health in Diabetes] trial). RESEARCH DESIGN AND METHODS Macronutrient oxidation rates under fasting and hyperinsulinemic conditions (clamp at 80 mU/m(2) per min), body composition (dual-energy X-ray absorptiometry), and relevant hormonal/metabolic blood variables were assessed in 59 type 2 diabetic and 42 nondiabetic individuals matched for obesity, sex, and race. Measures were repeated in diabetic participants after weight loss. RESULTS Metabolic flexibility to glucose (change in respiratory quotient [RQ]) was mainly related to insulin-stimulated glucose disposal rate (R(2) = 0.46, P < 0.0001) with an additional 3% of variance accounted for by plasma free fatty acid concentration at the end of the clamp (P = 0.03). The impaired metabolic flexibility to glucose observed in type 2 diabetic versus nondiabetic subjects (Delta RQ 0.06 +/- 0.01 vs. 0.10 +/- 0.01, respectively, P < 0.0001) was no longer observed after adjusting for glucose disposal rate (P = 0.19). Additionally, the increase in metabolic flexibility to glucose after weight loss was accounted for by the concomitant increase in insulin-stimulated glucose disposal rate. CONCLUSIONS This study suggests that metabolic inflexibility to glucose in type 2 diabetic subjects is mostly related to defective glucose transport.
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Affiliation(s)
- Jose E. Galgani
- Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - Leonie K. Heilbronn
- Pennington Biomedical Research Center, Baton Rouge, Louisiana
- Garvan Institute of Medical Research, New South Wales, Australia
| | - Koichiro Azuma
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - David E. Kelley
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jeanine B. Albu
- New York Obesity Research Center, St. Luke's Roosevelt Hospital Center, New York, New York
| | - Xavier Pi-Sunyer
- New York Obesity Research Center, St. Luke's Roosevelt Hospital Center, New York, New York
| | - Steven R. Smith
- Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, Louisiana
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GOHDA T, GOTOH H, TANIMOTO M, SATO M, IO H, KANEKO K, HAMADA C, TOMINO Y. Relationship between Abdominal Fat Accumulation and Insulin Resistance in Hemodialysis Patients. Hypertens Res 2008; 31:83-8. [DOI: 10.1291/hypres.31.83] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
There has been an increase in the concern about preventing type 2 diabetes mellitus (T2DM), a disease with great and increasing prevalence. The prevalence of obesity, physical inactivity, Western processed diet, important risk factors for the development of T2DM, are also rising. Free fatty acids are increased in obesity and reduce insulin clearance and increase hepatic glucose production. Implementation of a healthy lifestyle has been show to slow the progression of impaired glucose tolerance to T2DM. Orlistat is an inhibitor of lipase activity, with proved efficacy in body weight reduction and long-term management of obesity and more favorable effects on carbohydrate metabolism and it was prospectively shown in XENDOS study that orlistat promoted long-term weight loss and prevented T2DM onset in obese individuals with normal and impaired glucose tolerance at baseline over four years. This benefit could be associated to the weight loss itself, to the limited absorption of lipids and reduction of plasma free fatty acids, to increased production of incretins or to modulation of secretion of cytokines by adipocytes, all effects secondary to orlistat treatment. A proposed strategy is to identify subjects at highest risk to receive a drug intervention, using lifestyle interventions alone at the community level.
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Affiliation(s)
- Marcio C Mancini
- Obesity and Metabolic Syndrome Group, Endocrinology and Metabolism Department, Faculty of Medicine, University of São Paulo, São Paulo, SP, Brazil.
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35
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Wang CP, Chung FM, Shin SJ, Lee YJ. Congenital and environmental factors associated with adipocyte dysregulation as defects of insulin resistance. Rev Diabet Stud 2007; 4:77-84. [PMID: 17823691 PMCID: PMC2036262 DOI: 10.1900/rds.2007.4.77] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The metabolic syndrome refers to insulin resistance and its associated cluster of related cardiovascular metabolic risk factors including type 2 diabetes, hypertension, dyslipidemia and central obesity. Although many hypotheses and facts have been proposed to explain the interaction between genetic and environmental causes of this syndrome, the primary etiology of the metabolic syndrome is adipose tissue dysregulation. Firstly, the thrifty genotype and phenotype hypothesis may explain the endemic increase in type 2 diabetes and cardiovascular disease in developing countries and elucidates the congenital susceptibility and environmental triggering of the metabolic syndrome. Secondly, over-nutrition leads to fatty acid (FA) accumulation in adipocytes and to an overflow to ectopic fat storage organs. This causes functional changes in adipocytes shifting the intra-cellular metabolic pathway toward insulin resistance. Thirdly, obese subjects exhibit increased fat cell size and over-secretion of biologic adipocytokines. Fourthly, failure to adequately develop adipose tissue mass, as seen in lipodystrophy cases, causes severe insulin resistance and diabetes. Lastly, similar to human type 2 diabetes, Psammonys obesus, a desert rat which feeds mainly on low-calorie vegetation, develops the metabolic syndrome when given a diet of calorie rich food. The above evidence indicates adipocyte dysregulation and secretion of FA as well as certain molecules from overloaded adipocytes/adipokines contribute to the pathogenesis of impaired insulin secretion and insulin resistance, endothelial dysfunction, a pro-inflammatory state and promote progression of atherosclerosis. The metabolic syndrome is a modern disease resulting adipocyte dysmetabolism resulting from the paradox of the slow human evolution combined with rapid environmental changes.
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Affiliation(s)
- Chao-Ping Wang
- Division of Cardiology, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung, 82445 Taiwan
| | - Fu-Mei Chung
- Division of Cardiology, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung, 82445 Taiwan
| | - Shyi-Jang Shin
- Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, 80307 Taiwan
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Azuma K, Heilbronn LK, Albu JB, Smith SR, Ravussin E, Kelley DE. Adipose tissue distribution in relation to insulin resistance in type 2 diabetes mellitus. Am J Physiol Endocrinol Metab 2007; 293:E435-42. [PMID: 17440034 PMCID: PMC5684697 DOI: 10.1152/ajpendo.00394.2006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Insulin resistance (IR) is typically more severe in obese individuals with type 2 diabetes (T2DM) than in similarly obese non-diabetics but whether there are group differences in body composition and whether such differences contribute to the more severe IR of T2DM is uncertain. DEXA and regional CT imaging were conducted to assess adipose tissue (AT) distribution and fat content in liver and muscle in 67 participants with T2DM (F39/M28, age 60 +/- 7 yr, BMI 34 +/- 3 kg/m(2)) and in 35 similarly obese, non-DM volunteers (F20/M15, age 55 +/- 8 yr, BMI 33 +/- 2 kg/m(2)). A biopsy of subcutaneous abdominal AT was done to measure adipocyte size. A glucose clamp was performed at an insulin infusion of 80 mU x min(-1) x m(-2). There was more severe IR in T2DM (6.1 +/- 2.3 vs. 9.9 +/- 3.3 mg x min(-1) x kg FFM(-1); P < 0.01). Group comparisons of body composition parameters was performed after adjusting for the effect of age, gender, race, height and total fat mass (FM). T2DM was associated with less leg FM (-1.2 +/- 0.4 kg, P < 0.01), more trunk FM (+1.1 +/- 0.4 kg, P < 0.05), greater hepatic fat (P < 0.05), and more subfascial adipose tissue around skeletal muscle (P < 0.05). There was a significant group x sex interaction for VAT (P < 0.01), with greater VAT in women with T2DM (P < 0.01). Mean adipocyte size (AS) did not significantly differ across groups, and smaller AS was associated with increased leg FM, whereas larger AS was related to more trunk FM (both P < 0.05). Group differences in IR were less after adjusting for group differences in leg FM, trunk FM, and hepatic fat, but these adjustments only partially accounted for the greater severity of IR in T2DM. In summary, T2DM, compared with similarly obese nondiabetic men and women, is associated with less leg FM and greater trunk FM and hepatic fat.
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Affiliation(s)
- Koichiro Azuma
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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Abstract
Obesity and impaired glucose tolerance are associated with a greater risk for a number of conditions, including insulin resistance, diabetes mellitus, hypertension, dyslipidemia, coagulation abnormalities, inflammatory markers, and coronary heart disease. Lifestyle changes can delay or prevent the development of type 2 diabetes in patients with obesity and impaired glucose tolerance. The risks improve with weight loss and increased physical activity. A decrease of 7% to 10% or more from baseline weight can have a significant effect. This has now been documented in a number of randomized, controlled studies.
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Affiliation(s)
- F Xavier Pi-Sunyer
- Columbia University, St. Luke's-Roosevelt Hospital Center, 1111 Amsterdam Avenue, New York, NY 10025, USA.
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Ukropcova B, Sereda O, de Jonge L, Bogacka I, Nguyen T, Xie H, Bray GA, Smith SR. Family history of diabetes links impaired substrate switching and reduced mitochondrial content in skeletal muscle. Diabetes 2007; 56:720-7. [PMID: 17327442 DOI: 10.2337/db06-0521] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Insulin resistance is associated with metabolic inflexibility, impaired switching of substrate oxidation from fatty acids to glucose in response to insulin. Impaired switching to fat oxidation in response to a high-fat diet (HFD) is hypothesized to contribute to insulin resistance. The objective of this study was to test the hypothesis that defects in substrate switching in response to insulin and a HFD are linked to reduced mitochondrial biogenesis and occur before the development of diabetes. Metabolic flexibility was measured in young sedentary men with (n = 16) or without (n = 34) a family history of diabetes by euglycemic-hyperinsulinemic clamp. Flexibility correlated with fat oxidation measured in a respiratory chamber after a 3-day HFD. Muscle mitochondrial content was higher in flexible subjects with high fat oxidation after a HFD and contributed 49% of the variance. Subjects with a family history of diabetes were inflexible and had reduced HFD-induced fat oxidation and muscle mitochondrial content but did not differ in the amount of body or visceral fat. Metabolic inflexibility, lower adaptation to a HFD, and reduced muscle mitochondrial mass cluster together in subjects with a family history of diabetes, supporting the role of an intrinsic metabolic defect of skeletal muscle in the pathogenesis of insulin resistance.
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Affiliation(s)
- Barbara Ukropcova
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA
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Tarnopolsky MA, Rennie CD, Robertshaw HA, Fedak-Tarnopolsky SN, Devries MC, Hamadeh MJ. Influence of endurance exercise training and sex on intramyocellular lipid and mitochondrial ultrastructure, substrate use, and mitochondrial enzyme activity. Am J Physiol Regul Integr Comp Physiol 2006; 292:R1271-8. [PMID: 17095651 DOI: 10.1152/ajpregu.00472.2006] [Citation(s) in RCA: 296] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Impaired mitochondrial function and structure and intramyocellular lipid (IMCL) accumulation have been associated with obesity and Type 2 diabetes. We examined whether endurance exercise training and sex influenced IMCL and mitochondrial morphology using electron microscopy, whole-body substrate use, and mitochondrial enzyme activity. Untrained men (n = 5) and women (n = 7) were tested before and after 7 wk of endurance exercise training. Testing included 90 min of cycle ergometry at 60% Vo(2 peak) with preexercise muscle biopsies analyzed for IMCL and mitochondrial size/area using electron microscopy and short-chain beta-hydroxyacyl-CoA dehydrogenase (SCHAD) and citrate synthase (CS) enzyme activity. Training increased the mean lipid area density (P = 0.090), the number of IMCL droplets (P = 0.055), the number of IMCL droplets in contact with mitochondria (P = 0.010), the total mitochondrial area (P < 0.001), and the size of individual mitochondrial fragments (P = 0.006). Women had higher mean lipid area density (P = 0.030) and number of IMCL droplets (P = 0.002) before and after training, but higher individual IMCL area only before training (P = 0.013), compared with men. Women oxidized more fat (P = 0.027) and less carbohydrate (P = 0.032) throughout the study. Training increased Vo(2 peak) (P < 0.001), %fat oxidation (P = 0.018), SCHAD activity (P = 0.003), and CS activity (P = 0.042). In summary, endurance exercise training increased IMCL area density due to an increase in the number of lipid droplets, whereas the increase in total mitochondrial area was due to an increase in the size of individual mitochondrial fragments. In addition, women have higher IMCL content compared with men due mainly to a greater number of individual droplets. Finally, endurance exercise training increased the proportion of IMCL in physical contact with mitochondria.
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Affiliation(s)
- Mark A Tarnopolsky
- Department of Pediatrics and Medicine, Rm. 2H26, McMaster University Medical Centre, 1200 Main St. West, Hamilton, Ontario L8N 3Z5, Canada.
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Abstract
The clinical efficacy of currently available thiazolidinediones (TZDs) in improving glycaemic control and ameliorating several risk factors for cardiovascular disease (linked to their insulin-sensitising actions as well as direct vascular effects) is well established. Treatment-associated weight gain, however, which has been identified as a class effect of the TZDs, is seen in a number of patients. The magnitude of weight gain correlates in part with improved metabolic control, i.e. better responders are more prone to increases in body weight. The cardiovascular risk associated with obesity appears to be depot specific; while peripheral obesity is associated with a low risk of cardiovascular complications, central obesity confers a greater degree of risk. Evidence is reviewed that increases in body weight associated with TZD treatment are associated with neutral effects (or even, decreases) in visceral fat, the adipose depot that is associated with central obesity.
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Affiliation(s)
- J Wilding
- Diabetes and Endocrinology Clinical Research Group, Department of Medicine, Clinical Sciences Centre,University Hospital Aintree, Liverpool, UK.
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Hadigan C, Kamin D, Liebau J, Mazza S, Barrow S, Torriani M, Rubin R, Weise S, Fischman A, Grinspoon S. Depot-specific regulation of glucose uptake and insulin sensitivity in HIV-lipodystrophy. Am J Physiol Endocrinol Metab 2006; 290:E289-98. [PMID: 16131513 PMCID: PMC3197775 DOI: 10.1152/ajpendo.00273.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Altered fat distribution is associated with insulin resistance in HIV, but little is known about regional glucose metabolism in fat and muscle depots in this patient population. The aim of the present study was to quantify regional fat, muscle, and whole body glucose disposal in HIV-infected men with lipoatrophy. Whole body glucose disposal was determined by hyperinsulinemic clamp technique (80 mU x m(-2) x min(-1)) in 6 HIV-infected men and 5 age/weight-matched healthy volunteers. Regional glucose uptake in muscle and subcutaneous (SAT) and visceral adipose tissue (VAT) was quantified in fasting and insulin-stimulated states using 2-deoxy-[18F]fluoro-D-glucose positron emission tomography. HIV-infected subjects with lipoatrophy had significantly increased glucose uptake into SAT (3.8 +/- 0.4 vs. 2.3 +/- 0.5 micromol x kg tissue(-1) x min(-1), P < 0.05) in the fasted state. Glucose uptake into VAT did not differ between groups. VAT area was inversely related with whole body glucose disposal, insulin sensitivity, and muscle glucose uptake during insulin stimulation. VAT area was highly predictive of whole body glucose disposal (r2 = 0.94, P < 0.0001). This may be mediated by adiponectin, which was significantly associated with VAT area (r = -0.75, P = 0.008), and whole body glucose disposal (r = 0.80, P = 0.003). This is the first study to directly demonstrate increased glucose uptake in subcutaneous fat of lipoatrophic patients, which may partially compensate for loss of SAT. Furthermore, we demonstrate a clear relationship between VAT and glucose metabolism in multiple fat and muscle depots, suggesting the critical importance of this depot in the regulation of glucose and highlighting the significant potential role of adiponectin in this process.
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Affiliation(s)
- C Hadigan
- Program in Nutritional Metabolism, Massachusetts General Hospital, 55 Fruit St., LON 207, Boston, MA 02114, USA.
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Bos G, Snijder MB, Nijpels G, Dekker JM, Stehouwer CDA, Bouter LM, Heine RJ, Jansen H. Opposite contributions of trunk and leg fat mass with plasma lipase activities: the Hoorn study. ACTA ACUST UNITED AC 2006; 13:1817-23. [PMID: 16286530 DOI: 10.1038/oby.2005.221] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Lipoprotein lipase (LPL) and hepatic lipase (HL) are essential in hydrolysis of triglyceride-rich lipoproteins. LPL activity is negatively, whereas HL activity is positively, associated with total body fat. We determined the associations of trunk and leg fat mass with plasma LPL and HL activities in a cross-sectional study. RESEARCH METHODS AND PROCEDURES LPL and HL activities were determined in post-heparin plasma in a sample of 197 men and 209 women, 60 to 87 years of age. A total body DXA scan was performed to determine trunk and leg fat mass. RESULTS In women, but not in men, trunk fat mass was negatively associated with LPL activity, whereas leg fat mass was positively associated, after mutual adjustment and adjustment for age. Standardized betas (95% confidence interval) for trunk and leg fat mass were -0.24 (-0.41; -0.08) and 0.14 (-0.02; 0.31), respectively (interaction by sex, p = 0.03). Larger trunk fat mass was associated with higher HL activity in men [0.48 (0.28; 0.68)] and women [0.40 (0.24; 0.56)]. A negative association of leg fat mass and HL activity was observed in men, although not statistically significant [-0.13 (-0.33; 0.06)], and in women [-0.28 (-0.38; -0.18)]. DISCUSSION Abdominal fat is associated with unfavorable and femoral fat with favorable LPL and HL activities in plasma.
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Affiliation(s)
- Griët Bos
- Institute for Research in Extramural Medicine, VU University Medical Center, Amsterdam, The Netherlands.
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Abstract
For many years adipose tissue was viewed as the site where excess energy was stored, in the form of triglycerides (TGs), and where that energy, when needed elsewhere in the body, was released in the form of fatty acids (FAs). Recently, it has become clear that when the regulation of the storage and release of energy by adipose tissue is impaired, plasma FA levels become elevated and excessive metabolism of FA, including storage of TGs, occurs in nonadipose tissues. Most recently, work by several laboratories has made it clear that in addition to FA, adipose tissue communicates with the rest of the body by synthesizing and releasing a host of secreted molecules, collectively designated as adipokines. Several recent reviews have described how these molecules, along with FA, significantly effect total body glucose metabolism and insulin sensitivity. Relatively little attention has been paid to the effects of adipokines on lipid metabolism. In this review, we will describe, in detail, the effects of molecules secreted by adipose tissue, including FA, leptin, adiponectin, resistin, TNF-alpha, IL-6, and apolipoproteins, on lipid homeostasis in several nonadipose tissues, including liver, skeletal muscle, and pancreatic beta cells.
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Affiliation(s)
- Yi-Hao Yu
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
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Cha BS, Ciaraldi TP, Park KS, Carter L, Mudaliar SR, Henry RR. Impaired fatty acid metabolism in type 2 diabetic skeletal muscle cells is reversed by PPARgamma agonists. Am J Physiol Endocrinol Metab 2005; 289:E151-9. [PMID: 15727952 DOI: 10.1152/ajpendo.00141.2004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The impact of type 2 diabetes on the ability of muscle to accumulate and dispose of fatty acids and triglycerides was evaluated in cultured muscle cells from nondiabetic (ND) and type 2 diabetic (T2D) subjects. In the presence of 5 microM palmitate, T2D muscle cells accumulated less lipid than ND cells (11.5 +/- 1.2 vs. 15.1 +/- 1.4 nmol/mg protein, P < 0.05). Chronic treatment (4 days) with the peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist troglitazone increased palmitate accumulation, normalizing uptake in T2D cells. There were no significant differences between groups with regard to the relative incorporation of palmitate into neutral lipid species. This distribution was also unaffected by troglitazone treatment. beta-Oxidation of both long-chain (palmitate) and medium-chain (octanoate) fatty acids in T2D muscle cells was reduced by approximately 40% compared with ND cells. Palmitate oxidation occurred primarily in mitochondrial ( approximately 40-50% of total) and peroxisomal (20-30%) compartments. The diabetes-related defect in palmitate oxidation was localized to the mitochondrial component. Both palmitate and octanoate oxidation were stimulated by a series of thiazolidinediones. Oxidation in T2D muscle cells was normalized after treatment. Troglitazone increased the mitochondrial component of palmitate oxidation. Skeletal muscle cells from T2D subjects express defects in free fatty acid metabolism that are retained in vitro, most importantly defects in beta-oxidation. These defects can be corrected by treatment with PPARgamma agonists. Augmentation of fatty acid disposal in skeletal muscle, potentially reducing intramyocellular triglyceride content, may represent one mechanism for the lipid-lowering and insulin-sensitizing effects of thiazolidinediones.
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Affiliation(s)
- Bong-Soo Cha
- Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA
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45
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Tamura Y, Tanaka Y, Sato F, Choi JB, Watada H, Niwa M, Kinoshita J, Ooka A, Kumashiro N, Igarashi Y, Kyogoku S, Maehara T, Kawasumi M, Hirose T, Kawamori R. Effects of diet and exercise on muscle and liver intracellular lipid contents and insulin sensitivity in type 2 diabetic patients. J Clin Endocrinol Metab 2005; 90:3191-6. [PMID: 15769987 DOI: 10.1210/jc.2004-1959] [Citation(s) in RCA: 227] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Insulin resistance is associated with the circulating free fatty acid (FFA) level and intracellular lipid content in muscle and liver. We investigated the effect of 2-wk diet and exercise therapy on total adiposity, circulating FFA, intracellular lipid content in muscle and liver, and peripheral insulin sensitivity. Type 2 diabetic patients were divided into a diet group (n = 7) and a diet plus exercise group (n = 7). We performed a hyperinsulinemic-euglycemic clamp study before and after treatment. Intramyocellular lipid (IMCL) in the tibialis anterior muscle and intrahepatic lipid (IHL) were evaluated by (1)H-magnetic resonance spectroscopy. Fasting FFA were not altered, and total body fat showed a slight, but significant, decrease in both groups after treatment. IMCL was decreased by 19%, and the glucose infusion rate was increased by 57% in the diet plus exercise group, whereas neither IMCL nor glucose infusion rate was significantly altered in the diet group. However, IHL showed a significant decrease in both groups. In summary, we found that 2 wk of diet and exercise decreased IMCL and increased muscle insulin-mediated glucose uptake, whereas diet with or without exercise decreased IHL. These effects were evident despite a small decrease in body fat and were observed independently of fasting FFA levels.
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Affiliation(s)
- Yoshifumi Tamura
- Department of Medicine, Metabolism and Endocrinology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
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Bertoldo A, Price J, Mathis C, Mason S, Holt D, Kelley C, Cobelli C, Kelley DE. Quantitative assessment of glucose transport in human skeletal muscle: dynamic positron emission tomography imaging of [O-methyl-11C]3-O-methyl-D-glucose. J Clin Endocrinol Metab 2005; 90:1752-9. [PMID: 15613423 DOI: 10.1210/jc.2004-1092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Insulin-stimulated glucose transport in skeletal muscle is regarded as a key determinant of insulin sensitivity, yet isolation of this step for quantification in human studies is a methodological challenge. One notable approach is physiological modeling of dynamic positron emission tomography (PET) imaging using 2-[18-fluoro]2-deoxyglucose ([(18)F]FDG); however, this has a potential limitation in that deoxyglucose undergoes phosphorylation subsequent to transport, complicating separate estimations of these steps. In the current study we explored the use of dynamic PET imaging of [(11)C]3-O-methylglucose ([(11)C]3-OMG), a glucose analog that is limited to bidirectional glucose transport. Seventeen lean healthy volunteers with normal insulin sensitivity participated; eight had imaging during basal conditions, and nine had imaging during euglycemic insulin infusion at 30 mU/min.m(2). Dynamic PET imaging of calf muscles was conducted for 90 min after the injection of [(11)C]3-OMG. Spectral analysis of tissue activity indicated that a model configuration of two reversible compartments gave the strongest statistical fit to the kinetic pattern. Accordingly, and consistent with the structure of a model previously used for [(18)F]FDG, a two-compartment model was applied. Consistent with prior [(18)F]FDG findings, insulin was found to have minimal effect on the rate constant for movement of [(11)C]3-OMG from plasma to tissue interstitium. However, during insulin infusion, a robust and highly significant increase was observed in the kinetics of inward glucose transport; this and the estimated tissue distribution volume for [(11)C]3-OMG increased 6-fold compared with basal conditions. We conclude that dynamic PET imaging of [(11)C]3-OMG offers a novel quantitative approach that is both chemically specific and tissue specific for in vivo assessment of glucose transport in human skeletal muscle.
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Charbonnel B, Roden M, Urquhart R, Mariz S, Johns D, Mihm M, Widel M, Tan M. Pioglitazone elicits long-term improvements in insulin sensitivity in patients with type 2 diabetes: comparisons with gliclazide-based regimens. Diabetologia 2005; 48:553-60. [PMID: 15739120 DOI: 10.1007/s00125-004-1651-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 11/12/2004] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Recent studies have demonstrated that pioglitazone (PIO) has beneficial effects on insulin sensitivity compared with placebo in patients with type 2 diabetes. The effects of PIO and gliclazide (GLIC)-based therapy on insulin sensitivity have not previously been directly compared. This analysis aimed to compare the effects of 52 weeks of treatment with PIO (30-45 mg/day) and GLIC (80-320 mg/day), both titrated to maximum tolerable doses, as monotherapy or in combination with metformin (MET), on insulin sensitivity and lipid parameters known to be related to insulin sensitivity in patients with type 2 diabetes. METHODS We performed an analysis of 1,880 patients with inadequately controlled type 2 diabetes (HbA1c 7.5-11.0%) who were participants in two parallel-group, double-blind, double-dummy, randomised, multicentre, clinical trials. Measures of insulin sensitivity and lipids were assessed. RESULTS The PIO- and GLIC-based regimens produced similar levels of glycaemic control (HbA1c). In both trials, insulin sensitivity as assessed using the homeostasis model assessment was improved in patients receiving PIO, but decreased in those receiving GLIC (mean change, baseline to endpoint: PIO 15.5, GLIC -15.6; p<0.001 and PIO+MET 18.9, GLIC+MET -5.3; p<0.001). Improvements in the atherogenic index of plasma (mean change: PIO -0.17, GLIC -0.08; p<0.001 and PIO+MET -0.17, GLIC+MET -0.02; p<0.001), triglycerides (mean change, mmol/l: PIO+MET -0.62, GLIC+MET -0.22; p<0.001) and NEFA (mean change, mmol/l: PIO+MET -0.12, GLIC+MET-0.05; p<0.001) were greater in PIO-treated patients than in patients receiving GLIC. CONCLUSIONS/INTERPRETATION The PIO-based regimens resulted in improved insulin sensitivity and more favourable insulin sensitivity-related lipid profiles compared with the GLIC-based regimens. These benefits may be important in the management of cardiovascular risk in patients with type 2 diabetes.
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Affiliation(s)
- B Charbonnel
- Endocrinology Clinic, Hotel Dieu Hospital, Nantes, France
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Bülow B, Link K, Ahrén B, Nilsson AS, Erfurth EM. Survivors of childhood acute lymphoblastic leukaemia, with radiation-induced GH deficiency, exhibit hyperleptinaemia and impaired insulin sensitivity, unaffected by 12 months of GH treatment. Clin Endocrinol (Oxf) 2004; 61:683-91. [PMID: 15579181 DOI: 10.1111/j.1365-2265.2004.02149.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Adult survivors of childhood acute lymphoblastic leukaemia (ALL) often exhibit GH deficiency (GHD), due to prophylactic cranial radiotherapy (CRT). It is not known whether the observed risk for adiposity in these patients is associated with impaired insulin sensitivity and whether the insulin sensitivity is affected by GH replacement therapy. SUBJECTS AND DESIGN Eleven patients with GHD (median age 29 years), previously given prophylactic CRT for ALL, and 11 sex-, age- and body mass index (BMI)-matched controls were investigated with bioimpedance analysis (BIA) and analysis of serum leptin, serum free fatty acids (FFA) and serum insulin. Insulin sensitivity was measured by a euglycaemic-hyperinsulinaemic clamp technique (IS-clamp). Moreover, the effects of 12 months of individually titrated GH treatment (median dose 0.5 mg/day) on these parameters were investigated. RESULTS At baseline, the patients had lower fat free mass (FFM) (P = 0.003), higher percentage fat mass (FM) (P = 0.05), serum insulin (P = 0.02) and serum leptin/kg FM (P = 0.01) than controls. The patients had a tendency towards impaired IS-clamp (P = 0.06), which disappeared after correction for body composition (IS-clamp/kg FFM; P > 0.5). In the patients, time since CRT was positively correlated with percentage FM (r = 0.70, P = 0.02), and there was an independent negative association between serum FFA and IS-clamp (P = 0.05). Twelve months of GH treatment increased serum IGF-I (P = 0.003) and FFM (P = 0.02) and decreased percentage FM (P = 0.03), but no significant changes were seen in serum leptin/kg FM, serum FFA, FFA-clamp, serum insulin or IS-clamp (all, P > or = 0.2). CONCLUSIONS Young adult survivors of childhood ALL with GHD had increased fat mass, hyperleptinaemia and impaired insulin sensitivity, which could be a consequence of radiation-induced impairment of GH secretion or mediated by other hypothalamic dysfunctions, such as leptin resistance or other unknown factors, affected by CRT. Twelve months of individualized GH replacement therapy led to positive effects on body composition, but the hyperleptinaemia, hyperinsulinaemia and the impaired insulin sensitivity remained unchanged.
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Freedland ES. Role of a critical visceral adipose tissue threshold (CVATT) in metabolic syndrome: implications for controlling dietary carbohydrates: a review. Nutr Metab (Lond) 2004; 1:12. [PMID: 15530168 PMCID: PMC535537 DOI: 10.1186/1743-7075-1-12] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Accepted: 11/05/2004] [Indexed: 12/25/2022] Open
Abstract
There are likely many scenarios and pathways that can lead to metabolic syndrome. This paper reviews mechanisms by which the accumulation of visceral adipose tissue (VAT) may contribute to the metabolic syndrome, and explores the paradigm of a critical VAT threshold (CVATT). Exceeding the CVATT may result in a number of metabolic disturbances such as insulin resistance to glucose uptake by cells. Metabolic profiles of patients with visceral obesity may substantially improve after only modest weight loss. This could reflect a significant reduction in the amount of VAT relative to peripheral or subcutaneous fat depots, thereby maintaining VAT below the CVATT. The CVATT may be unique for each individual. This may help explain the phenomena of apparently lean individuals with metabolic syndrome, the so-called metabolically normal weight (MONW), as well as the obese with normal metabolic profiles, i.e., metabolically normal obese (MNO), and those who are "fit and fat." The concept of CVATT may have implications for prevention and treatment of metabolic syndrome, which may include controlling dietary carbohydrates. The identification of the CVATT is admittedly difficult and its anatomical boundaries are not well-defined. Thus, the CVATT will continue to be a work in progress.
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Affiliation(s)
- Eric S Freedland
- Boston University School of Medicine, 5 Bessom Street, No, 318, Marblehead, MA 01945, USA.
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Driscoll SD, Meininger GE, Ljungquist K, Hadigan C, Torriani M, Klibanski A, Frontera WR, Grinspoon S. Differential effects of metformin and exercise on muscle adiposity and metabolic indices in human immunodeficiency virus-infected patients. J Clin Endocrinol Metab 2004; 89:2171-8. [PMID: 15126538 DOI: 10.1210/jc.2003-031858] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The HIV-lipodystrophy syndrome is associated with fat redistribution and metabolic abnormalities, including insulin resistance (IR). The mechanisms and treatment strategies for IR in HIV-lipodystrophy are unclear, but data suggest that intramuscular lipids contribute to IR in this population. We previously showed that metformin and exercise improve hyperinsulinemia more than metformin alone in HIV-lipodystrophy. Now we investigate the effects of these treatment strategies on thigh muscle adiposity measured by computed tomography and additional body composition measures. Twenty-five HIV-infected patients on stable antiretroviral therapy with hyperinsulinemia and fat redistribution participated in a prospective, randomized, 3-month study of metformin alone or metformin and resistance training three times a week. Thigh muscle adiposity decreased significantly more as shown by increased muscle attenuation [2.0 (range, 0.5-5.0) vs. -1.0 (-3.5-0), P = 0.04] and sc leg fat tended to decrease more [-3.3 (-7.5-4.3) vs. 0.8 (-2.1-9.5), P = 0.06] in the combined treatment group in comparison with metformin alone. In multivariate analysis, change in thigh muscle adiposity remained a significant predictor of change in insulin (P = 0.04), controlling for changes in other body composition measurements. These data suggest that muscle adiposity, in addition to other fat depots, is an important determinant of hyperinsulinemia and that exercise has complex effects on regional fat depots in HIV-infected patients. Reduction in muscle adiposity may be an important mechanism by which exercise improves hyperinsulinemia in this population.
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Affiliation(s)
- Susan D Driscoll
- Program in Nutritional Metabolism, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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