Total Body Energy Expenditure Research Articles

Moringa (Moringa oleifera) leaves aqueous extract enhances fibronectin type III domain-containing protein 5 gene expression and serum irisin liberation in an obesity model

Background Obesity, a risk agent for many chronic diseases, leads to increased mortality and poses one of the major public health problems. Objective This study aimed to investigate the thermogenic and antiobese efficiency of Moringa aqueous extract (MAE) on obese-modeled rats. Materials and methods Adult male rats (150–170 g) were randomly divided into four groups, with 10 animals each, as follows: (a) healthy rats served as control, (b) healthy rats administrated with MAE (400 mg/kg/day), (c) obese-modeled rats, and (d) obese-modeled rats treated with MAE. Results After 30 consecutive days of treatment, the obtained results declared that MAE possessed antiobesity, thermogenic, antilipidemic, and antiinflammatory potential. MAE succeeded significantly in reduction of the BMI and serum leptin level coupled with up-regulation of fibronectin type III domain-containing protein 5 gene mRNA expression and serum irisin level. It clearly increased serum paraoxonase-1 activity and improved lipid profile values. Moreover, it markedly reduced serum tumor necrosis factor α and increased antioxidant activity, which was achieved from the marked improvement in malondialdehyde, nitric oxide, catalase, superoxide dismutase, and glutathione values in cardio-hepatic tissues. These findings were confirmed by the regeneration of the hepatic histopathological structure. Conclusion MAE, as a food supplement, could play a beneficial role in management of obesity and restoring its complications. This could be exhibited through multiple pathways, mainly via upregulation of fibronectin type III domain-containing protein 5 gene expression and production of the soluble myokine ‘irisin,’ which is responsible for browning of white adipose tissue as well as increment of total body energy expenditure.

Factors influencing basal metabolism of Czechs of working age from South Moravia.

Basal metabolic rate (BMR) is the main part of the total body energy expenditure. The value of BMR is individual and depends on a lot of factors. The goal of the research was to discover the influence of anthropometric parameters, age and gender, on changes of the BMR values. A total of 177 individuals of Czech Caucasian origin from South Moravia (BMI 27.3 ± 7.88 kg/m2) aged 18-55 (117 women, 60 men) were included in the study. Selected anthropometric characteristics were measured using a stadiometer (SECA 213) and bioelectrical impedance analysis (Inbody 230). BMR was measured by indirect calorimetry (Cortex Metalyzer 3B). The measured values were statistically evaluated by the regression analysis and least square method (LSM). From the following results that the factors that influence the BMR value statistically significantly (p < 0.05) are: age, gender, body mass index, total body water, and percent of body fat. Body fat and age have both an indirect impact on the basal metabolic rate of the Czech population in working age. However, BMI and the total body water were discovered to have a direct influence on the BMR.

The Effects of Single versus Multiple Sets of Leg Presses on Myocardial Energy Expenditure

A popular trend in exercise regimes is to maximize the amount of work done in a minimum amount of time or maximize work by minimizing rest intervals. It is hoped that reduced rest time will result in dramatic fitness gains. To date, however, no differences in total energy expenditures have been found between high and low rest interval protocols. Unfortunately, total energy expenditures do reflect the metabolic strain experienced by the cardiac tissue. Rather, the rate pressure product [RPP = Systolic blood pressure × heart rate/1,000] has been recommended as a good index to assess cardiovascular metabolic stress, and to help determine the intensity and duration of exercise in developing fitness. PURPOSE: To determine if cardiac energy expenditure (i.e. RPP) differs between high rest (multiple sets) and low rest (single set) exercise protocols. METHODS: 14 untrained college students (5 male, 9 female; Age: 21.1 ± 0.2 years) participated in the study. Exercise intervention consisted of 2 days of multiple sets (4 sets,10 reps @ 150% body weight, 3 min interset rest) and 2 days of single set (40 reps @ 150% body weight) leg presses, randomly assigned in a balanced crossover order. At least 2 days separated each session and all sets were completed as fast as possible. HR and SBP were obtained on the right arm with an automated blood pressure machine at both pre-exercise and immediate post set completion. A paired T-test was used to compare the difference between the average final post set RPP of two trials of each exercise type. RESULTS: Multiple sets RPP (13.7± 0.8) was significantly less (t=6.5×10-5, p<0.05) than the single set RPP (17.5 ± 0.8). CONCLUSION: Contrary to total body energy expenditure research, a single set of exercise exerts more metabolic stress on the cardiovascular system than doing the same work with several rest intervals. Thus, single set of exercise could be used to train when attempting to train cardiac tissue, but multiple sets of exercise is recommended for people with compromised cardiovascular systems.

Irisin attenuates oxidized low-density lipoprotein impaired angiogenesis through AKT/mTOR/S6K1/Nrf2 pathway.

It is known that irisin increases total body energy expenditure, decreases body weight, and enhances insulin sensitivity. Although previous studies have demonstrated that irisin induces vascular endothelial cell (EC) angiogenesis, the molecular mechanisms underlying irisin-induced angiogenesis under conditions reflecting atherosclerosis are not known. The aim of the present study is to investigate whether irisin could inhibit oxidized low-density lipoprotein (oxLDL) impaired angiogenesis. We investigated the effect of irisin on angiogenesis in vitro by evaluating cell viability, cell migration, and the capacity to form capillary-like tubes using human umbilical vein endothelial cells and human microvascular endothelial cells (HUVECs and HMEC-1) that were treated with oxLDL. We also evaluated the effects of irisin on angiogenesis in vivo by Matrigel plug angiogenesis assay and in a chicken embryo membrane (CAM) model. Our results demonstrated that irisin increased oxLDL-treated EC viability as well as migration and tube formation. Moreover, oxLDL inhibited angiogenic response in vivo, both in the Matrigel plug angiogenesis assay and in the CAM model, and was attenuated by irisin. Furthermore, irisin decreased apoptosis, inflammatory cytokines, and intracellular reactive oxygen species (ROS) levels in oxLDL-treated EC. In addition, we found that irisin upregulated pAkt/mTOR/Nrf2 in oxLDL-treated EC. Both mTOR/Nrf2 shRNA and LY294002 could inhibit the protective effect of irisin. Taken together these results, they suggested that irisin attenuates oxLDL-induced vascular injury by activating the Akt/mTOR/Nrf2 pathway. Our findings suggest that irisin attenuates oxLDL-induced blood vessel injury.

Method and rationale for recalculating dilution spaces to a single, common time point in doubly labeled water studies.

The doubly labeled water (DLW) method has become widely used in studies of energy expenditure and body composition. Researchers differ in the analytical methods used to calculate the dilution spaces for deuterium and oxygen-18. Some determine dilution spaces using isotope enrichments extrapolated to the instant of dosing with DLW (slope-intercept method), but others use measured enrichments from body water samples obtained 3-10 h after dosing (plateau method). These differences limit the comparability of analyses across labs. I derive a simple mathematical approach for recalculating reported dilution spaces to any time point post dosing, using reported dilution spaces and rates of isotope depletion. Simulated data are used to examine the effects of different dilution space protocols. Recalculating dilution spaces enables researchers to determine outcome variables of interest (e.g., total body water, energy expenditure, and water throughput) from different labs under a unified protocol for determining dilution spaces, and improves comparisons among studies. Differences between dilution space protocols can lead to substantial differences in outcome variables of interest in DLW studies. When comparing results of DLW studies that employ different dilution space protocols, dilution spaces should be recalculated for a common time point, and outcome variables recalculated as needed, prior to comparison across studies.

Ilex paraguariensis modulates fat metabolism in Caenorhabditis elegans through purinergic system (ADOR-1) and nuclear hormone receptor (NHR-49) pathways.

Ilex paraguariensis is a well-known plant that is widely consumed in South America, primarily as a drink called mate. Mate is described to have stimulant and medicinal properties. Considering the potential anti-lipid effects of I. paraguariensis infusion, we used an extract of this plant as a possible modulator of fat storage to control lipid metabolism in worms. Herein, the I. paraguariensis-dependent modulation of fat metabolism in Caenorhabditis elegans was investigated. C. elegans were treated with I. paraguariensis aqueous extract (1 mg/ml) from L1 larvae stage until adulthood, to simulate the primary form of consumption. Expression of adipocyte triglyceride lipase 1 (ATGL-1) and heat shock protein 16.2, lipid accumulation through C1-BODIPY-C12 (BODIPY) lipid staining, behavioral parameters, body length, total body energy expenditure and overall survival were analyzed. Total body energy expenditure was determined by the oxygen consumption rate in N2, nuclear hormone receptor knockout, nhr-49(nr2041), and adenosine receptor knockout, ador-1(ox489) strains. Ilex paraguariensis extract increased ATGL-1 expression 20.06% and decreased intestinal BODIPY fat staining 63.36%, compared with the respective control group, without affecting bacterial growth and energetic balance, while nhr-49(nr2041) and ador-1(ox489) strains blocked the worm fat loss. In addition, I. paraguariensis increased the oxygen consumption in N2 worms, but not in mutant strains, increased N2 worm survival following juglone exposure, and did not alter hsp-16.2 expression. We demonstrate for the first time that I. paraguariensis can decrease fat storage and increase body energy expenditure in worms. These effects depend on the purinergic system (ADOR-1) and NHR-49 pathways. Ilex paraguariensis upregulated the expression of ATGL-1 to modulate fat metabolism. Furthermore, our data corroborates with other studies that demonstrate that C. elegans is a useful tool for studies of fat metabolism and energy consumption.

Isolation, Expansion, and Adipogenic Induction of CD34+CD31+ Endothelial Cells from Human Omental and Subcutaneous Adipose Tissue.

Obesity is accompanied by an extensive remodeling of adipose tissue primarily via adipocyte hypertrophy. Extreme adipocyte growth results in a poor response to insulin, local hypoxia, and inflammation. By stimulating the differentiation of functional white adipocytes from progenitors, radical hypertrophy of the adipocyte population can be prevented and, consequently, the metabolic health of adipose tissue can be improved along with a reduction of inflammation. Also, by stimulating a differentiation of beige/brown adipocytes, the total body energy expenditure can be increased, resulting in weight loss. This approach could prevent the development of obesity co-morbidities such as type 2 diabetes and cardiovascular disease. This paper describes the isolation, expansion, and differentiation of white and beige adipocytes from a subset of human adipose tissue endothelial cells that co-express the CD31 and CD34 markers. The method is relatively cheap and is not labor-intensive. It requires access to human adipose tissue and the subcutaneous depot is suitable for sampling. For this protocol, fresh adipose tissue samples from morbidly obese subjects [body mass index (BMI) >35] are collected during bariatric surgery procedures. Using a sequential immunoseparation from the stromal vascular fraction, enough cells are produced from as little as 2-3 g of fat. These cells can be expanded in culture over 10-14 days, can be cryopreserved, and retain their adipogenic properties with passaging up to passage 5-6. The cells are treated for 14 days with an adipogenic cocktail using a combination of human insulin and the PPARγ agonist-rosiglitazone. This methodology can be used for obtaining proof of concept experiments on molecular mechanisms that drive adipogenic responses in adipose endothelial cells, or for screening new drugs that can enhance the adipogenic response directed either towards white or beige/brown adipocyte differentiation. Using small subcutaneous biopsies, this methodology can be used to screen out non-responder subjects for clinical trials aimed to stimulate beige/brown and white adipocytes for the treatment of obesity and co-morbidities.

Pyruvate dehydrogenase complex plays a central role in brown adipocyte energy expenditure and fuel utilization during short-term beta-adrenergic activation

Activation of brown adipose tissue (BAT) contributes to total body energy expenditure through energy dissipation as heat. Activated BAT increases the clearance of lipids and glucose from the circulation, but how BAT accommodates large influx of multiple substrates is not well defined. The purpose of this work was to assess the metabolic fluxes in brown adipocytes during β3-adrenergic receptor (β3-AR) activation.T37i murine preadipocytes were differentiated into brown adipocytes and we used Seahorse respirometry employing a set of specific substrate inhibitors in the presence or absence of β3-AR agonist CL316,243. The main substrate used by these brown adipocytes were fatty acids, which were oxidized equally during activation as well as during resting condition. [U-13C]-glucose tracer-based metabolomics revealed that the flux through the TCA cycle was enhanced and regulated by pyruvate dehydrogenase (PDH) activity. Based on 13C-tracer incorporation in lipids, it appeared that most glucose was oxidized via TCA cycle activity, while some was utilized for glycerol-3-phosphate synthesis to replenish the triglyceride pool. Collectively, we show that while fatty acids are the main substrates for oxidation, glucose is also oxidized to meet the increased energy demand during short term β3-AR activation. PDH plays an important role in directing glucose carbons towards oxidation.

Both experimental hypothyroidism and hyperthyroidism increase cardiac irisin levels in rats.

Irisin is a newly discovered myokine and adipokine that increases total body energy expenditure. The aim of this study was to determine the effect of experimental hypothyroidism and hyperthyroidism on the levels of irisin in heart tissue in rats. The study was performed on the 40 male Sprague-Dawley rats. Experimental groups were designed as; Control, Hypothyroidism, Hypothyroidism+L-Thyroxine, Hyperthyroidism and Hyperthyroidism + PTU. Following 3 weeks experimental period, irisin levels were determined in heart tissues. Hypothyroidism group values of irisin were higher than in the control group, but lower than in the hyperthyroidism group. The hyperthyroidism group had the highest levels of cardiac irisin. The results of the study showed that the experimental hypothyroidism and hyperthyroidism increased the heart irisin levels, but the increase in the hyperthyroidism group was much higher than in the hypothyroidism group. However, treatment of hypothyroidism and hyperthyroidism corrected cardiac irisin levels (Fig. 1, Ref. 28).

Study of Serum Irisin in Patients with Thyroid Dysfunction

Background: irisin, identified as a proteolytic cleavage product of the fibronectin type III domain-containing protein 5 (FNDC5), It is a novel myokine secreted by contracting skeletal muscle, possibly mediating some exercise health benefits via ‘browning’ of white adipose tissue. Irisin causes a significant increase in total body energy expenditure and resistance to obesity-associated insulin resistance in mice, while controversy still exists concerning irisin origin, regulation and function in humans. Aim of the work: our study aimed to detect relation of thyroid status (hypo, hyperthyroid) with serum irisin, ck and peripheral neuropathy. Patient and methods: this study was conducted on 60 candidates consisted of 40 patients with thyroid dysfunction selected from Endocrine outpatient Clinic and Inpatient Department of Ain Shams University Hospitals and 20 healthy volunteers from April 2016 to October 2016. Informed consent was obtained from all participants. Patients of both genders, age more than 18 years old, 20 patients with hypothyroidism, 20 patients with hyperthyroidism and 20 healthy volunteers. We excluded significant renal, hepatic and cardiac disease, severe associated acute illness or depression, pregnant females, diabetes, hypercortisolism, hypocortisolism, muscular or neurological disorders, routinely taking drugs as statins, intensively involved in a sport or any strenuous physical activity. All participants were subjected to full medical history taking, general clinical examination and laboratory investigations as thyroid and thyroid-related hormone concentrations as well as a thyroid ultrasound examination and thyroid scan for patients with hyperthyroidism. Serum irisin level, CK and nerve conduction velocity were measured. Results: irisin level was higher in hyperthyroid group than euthyroid group with a significant difference. In comparison with normal NCV candidates and reduced NCV candidates with other variables there was only border line significant difference with irisin p-value. Non significant value of irisin and CK level were detected for diagnosis of hypothyroidism. Irisin has highly significant value for diagnosis of hyperthyroidism with (sen 95%, sp 42.5). Increased BMI is the only independent predictor for hypothyroidism by using multivariable binary logistic regression analysis. Decreased BMI and irisin are independent predictors for hyperthyroidism. Conclusion: serum irisin level is one of predictors for hyperthyroidism, on the other hand irisin does not have a significant value to predict hypothyroidism. Serum irisin was found to be higher in patients with hyperthyroidism in comparison with euthyroid participant with non statistically significant difference between hypo and hyperthyroidism. Serum CK level does not have a significant value in diagnosis of thyroid dysfunction (hypothyroidism or hyperthyroidism). Serum irisin level was low in thyroid dysfunction cases with delayed NCV compared to thyroid dysfunction cases and normal NCV with border line significant difference.

Abstract 447: ZAG promotes cachexia-associated white adipose tissue browning and energy wastage

Abstract Cancer cachexia is a complex condition of tissue wasting that affects up to 80% of cancer patients. To date, there is no effective treatment for cachexia due to the complex nature of this condition. Energy wasting in cachexia is caused by excessive lipid and protein turnover in the body, browning of white adipose tissue (WAT), and futile metabolic cycling such as glucose recycling between the liver and tumor. Therefore, identifying and inhibiting factors that promote WAT browning, and glucose and lipid recycling can reduce energy wasting and ameliorate cachexia in cancer patients. Zinc-α2-glycoprotein (ZAG), a lipid mobilizing factor secreted by multiple cancers, has been shown to promote lipolysis and inhibit lipogenesis in WAT. However, whether ZAG plays any role beyond lipolysis and participates in other energy wasting mechanisms of cachexia such as glucose and lipid recycling, and WAT browning has not been explored. Our initial studies indicate that while ZAG is highly expressed in the heart, kidney, and liver of wild-type mice, the basal expression of ZAG is very low in WAT at both the mRNA and protein levels. To investigate the metabolic functions of ZAG in vivo, ZAG-expressing 293 cells were implanted subcutaneously in athymic nude mice, and analyzed them after 3 and 6 weeks. We detected a 3-fold increase in the circulating plasma levels of ZAG. Importantly, the increase in ZAG levels was associated with a decrease in body weight gain without any differences in food consumption and physical activity. Morphological examination of eFAT pads of ZAG-cell implanted mice showed smaller size compared to controls. In addition, histological examination of eFAT showed cell shrinkage and almost complete depletion of fat stores, suggesting enhanced lipolysis in the WAT. Notably, ZAG induced the expression of beige, mitochondrial, and thermogenesis genes at mRNA level in the eFAT. Moreover, the expression of brown adipocyte-specific thermogenic genes such as Ebf2, Prdm16, PGC1α, UCP1, SRC1 and IRF4 were strongly induced at the protein level in eWAT of ZAG-cell implanted mice suggesting that ZAG causes WAT browning. Furthermore, metabolic analysis revealed increased O2 consumption and heat production in ZAG-cell implanted mice compared to controls indicating increased total body energy expenditure. ZAG-cell implanted mice also displayed reduced respiratory exchange ratio indicating increased consumption of lipids. Overall, our findings suggest that ZAG functions beyond lipolysis and causes significant energy wasting by causing WAT browning and promoting glucose and lipid catabolism in the beige cells. These findings suggest that ZAG plays a predominant role in the development of cachexia, and thus, may represent a novel therapeutic target to block energy wasting and delay or prevent cachexia in cancer patients. Citation Format: Sawsan Elattar, Satyanarayana Ande. ZAG promotes cachexia-associated white adipose tissue browning and energy wastage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 447. doi:10.1158/1538-7445.AM2017-447

Exercise-induced irisin in bone and systemic irisin administration reveal new regulatory mechanisms of bone metabolism

Irisin is a polypeptide hormone derived from the proteolytic cleavage of fibronectin-type III domain-containing 5 (FNDC5) protein. Once released to circulation upon exercise or cold exposure, irisin stimulates browning of white adipose tissue (WAT) and uncoupling protein 1 (UCP1) expression, leading to an increase in total body energy expenditure by augmented UCP1-mediated thermogenesis. It is currently unknown whether irisin is secreted by bone upon exercise or whether it regulates bone metabolism in vivo. In this study, we found that 2 weeks of voluntary wheel-running exercise induced high levels of FNDC5 messenger RNA as well as FNDC5/irisin protein expression in murine bone tissues. Increased immunoreactivity due to exercise-induced FNDC5/irisin expression was detected in different regions of exercised femoral bones, including growth plate, trabecular bone, cortical bone, articular cartilage, and bone–tendon interface. Exercise also increased expression of osteogenic markers in bone and that of UCP1 in WAT, and led to bodyweight loss. Irisin intraperitoneal (IP) administration resulted in increased trabecular and cortical bone thickness and osteoblasts numbers, and concurrently induced UCP1 expression in subcutaneous WAT. Lentiviral FNDC5 IP administration increased cortical bone thickness. In vitro studies in bone cells revealed irisin increases osteoblastogenesis and mineralization, and inhibits receptor activator of nuclear factor-kB ligand (RANKL)-induced osteoclastogenesis. Taken together, our findings show that voluntary exercise increases irisin production in bone, and that an increase in circulating irisin levels enhances osteogenesis in mice.

SERUM IRISIN LEVEL INCREASES THROUGHOUT THE GESTATIONAL PERIOD AND IT DOES NOT PLAY A ROLE IN DEVELOPMENT OF GESTATIONAL DIABETES MELLITUS.

Irisin is a recently discovered novel adipomyokine that induces an increase in total body energy expenditure, improves insulin sensitivity and glucose tolerance. It has been shown that circulating levels of irisin are low in patients with obesity, diabetes mellitus and impaired glucose tolerance. However, the information about the level of circulating irisin in gestational diabetes mellitus (GDM) is controversial. Serum irisin was measured by an ELISA in a longitudinal prospective cohort study in 221 women. There were 156 healthy pregnant and 65 women with GDM. Circulating irisin levels were significantlly higher in the middle pregnancy compared with early pregnancy levels in healthy pregnant women and in women with GDM. Serum irisin levels were found to be lower in GDM compared to healthy pregnant women during first trimester but the difference was not observed throughout the pregnancy and it was comparable in middle pregnancy. There was a significant inverse correlation of BMI with serum irisin (r = -0.193, p = 0.004) and between HbA1c and mean glucose of OGTT with serum irisin (r =-0.377, p =0.0001) and (r = -0.147, p:0.03) in the early pregnancy of pregnant women repectively. The present study shows that serum irisin level increases throughout the gestational period from early to middle pregnancy in women with GDM, but there is no effect of irisin on the development of GDM.

Effect of yoga training on lipid metabolism in industrial workers with reference to body constitution (Prakriti)

IntroductionThe progressive increase in dyslipidemia and physical inactivity are considered to be major risk factors for the onset of non communicable diseases. Awareness of body constitution plays a vital role to regularise optimum health. The present study was planned to evaluate the effect of yoga practices on lipid metabolism with reference to specific body constitution (Prakriti). MethodsA self-as-control study was conducted on 36 male healthy volunteers between age group of 30–58 years. Their prakriti analysis was done using standardized, validated questionnaire and were divided into Vata-Pitta (n = 16) and Pitta-Kapha (n = 20) groups. The assessment of lipid profile was done in fasting blood samples before and after 12 weeks of yoga training. Data were analyzed using paired t-test and independent t-test. ResultsAfter yoga intervention, the result of within group comparison revealed that in Vata-Pitta (V-P) group, significant decrease in the levels of TC, LDL (p < 0.001) and significant increase in HDL (p < 0.01) was observed. While, Pitta-Kapha (P-K) group showed significant decrease in TC (p < 0.001), TG (p < 0.01), LDL (p < 0.001) and VLDL (p < 0.05) levels. Further, the results between groups revealed that P-K group has significantly higher baseline levels of TC, TG and VLDL as compared to V-P group (p < 0.05). ConclusionThe study concludes that yoga practices can effectively regulate lipid metabolism and total body energy expenditure with reference to specific constitutional type (Prakriti) that may act as a tool to assess magnitude of metabolic functions.

Muscle activation and energy expenditure of sedentary behavior alternatives in young and old adults

The physiological mechanisms that underlie the metabolic benefits of breaking up sedentary behavior (SB) have yet to be determined. The purpose of this study is to compare energy expenditure (EE) and muscle activation (MA) responses to sitting and four SB alternatives in younger and older adults. Twenty-two adults, grouped by age (21–35 and 62–76 years), completed five randomly ordered 20 min tasks: (1) continuous sitting (Sit), (2) sitting on a stability ball (Ball), (3) continuous standing (Stand), (4) sitting interrupted by walking (S/W), and (5) sitting interrupted by standing (S/S). Muscle activation of two upper (trapezius and erector spinae) and two lower (rectus femoris and medial gastrocnemius) body muscles and total body EE were measured continuously. A linear mixed model using gender and age as a covariate with Bonferroni adjustment were used to determine significant differences between tasks. Collectively, S/W produced significantly higher MA and EE compared with Sit (p < 0.001). Stand and Ball provided significantly greater EE, but not MA, compared to Sit (p < 0.05), while S/S did not significantly change EE or MA compared to Sit. There were no net EE differences when comparing age groups across the tasks. Upper body MA was not consistent in both age groups across tasks. Specifically, during S/W the upper body MA of older adults (9.7 ± 1.5% MVC) was double that of young adults (4.8 ± 0.7% MVC, p = 0.006). Lower body MA responded similarly to all tasks in both age groups. Disrupting sitting with walking produced the largest increase in EE and MA compared to other SB alternatives in both age groups. These results are important considering the wide use of SB alternatives by researchers and public health practitioners.

Irisin Induces Angiogenesis in Human Umbilical Vein Endothelial Cells In Vitro and in Zebrafish Embryos In Vivo via Activation of the ERK Signaling Pathway

As a link between exercise and metabolism, irisin is assumed to be involved in increased total body energy expenditure, reduced body weight, and increased insulin sensitivity. Although our recent evidence supported the contribution of irisin to vascular endothelial cell (ECs) proliferation and apoptosis, further research of irisin involvement in the angiogenesis of ECs was not conclusive. In the current study, it was found that irisin promoted Human Umbilical Vein Endothelial Cell (HUVEC) angiogenesis via increasing migration and tube formation, and attenuated chemically-induced intersegmental vessel (ISV) angiogenic impairment in transgenic TG (fli1: GFP) zebrafish. It was further demonstrated that expression of matrix metalloproteinase (MMP) 2 and 9 were also up-regulated in endothelial cells. We also found that irisin activated extracellular signal–related kinase (ERK) signaling pathways. Inhibition of ERK signaling by using U0126 decreased the pro-migration and pro-angiogenic effect of irisin on HUVEC. Also, U0126 inhibited the elevated expression of MMP-2 and MMP-9 when they were treated with irisin. In summary, these findings provided direct evidence that irisin may play a pivotal role in maintaining endothelium homeostasis by promoting endothelial cell angiogenesis via the ERK signaling pathway.

Selective Impairment of Glucose but Not Fatty Acid or Oxidative Metabolism in Brown Adipose Tissue of Subjects With Type 2 Diabetes.

Spontaneous glucose uptake by brown adipose tissue (BAT) is lower in overweight or obese individuals and in diabetes. However, BAT metabolism has not been previously investigated in patients with type 2 diabetes during controlled cold exposure. Using positron emission tomography with (11)C-acetate, (18)F-fluoro-deoxyglucose ((18)FDG), and (18)F-fluoro-thiaheptadecanoic acid ((18)FTHA), a fatty acid tracer, BAT oxidative metabolism and perfusion and glucose and nonesterified fatty acid (NEFA) turnover were determined in men with well-controlled type 2 diabetes and age-matched control subjects under experimental cold exposure designed to minimize shivering. Despite smaller volumes of (18)FDG-positive BAT and lower glucose uptake per volume of BAT compared with young healthy control subjects, cold-induced oxidative metabolism and NEFA uptake per BAT volume and an increase in total body energy expenditure did not differ in patients with type 2 diabetes or their age-matched control subjects. The reduction in (18)FDG-positive BAT volume and BAT glucose clearance were associated with a reduction in BAT radiodensity and perfusion. (18)FDG-positive BAT volume and the cold-induced increase in BAT radiodensity were associated with an increase in systemic NEFA turnover. These results show that cold-induced NEFA uptake and oxidative metabolism are not defective in type 2 diabetes despite reduced glucose uptake per BAT volume and BAT "whitening."

Perinatal lead (Pb) exposure results in sex-specific effects on food intake, fat, weight, and insulin response across the murine life-course.

Developmental lead (Pb) exposure has been associated with lower body weight in human infants and late onset obesity in mice. We determined the association of perinatal Pb exposure in mice with changes in obesity-related phenotypes into adulthood. Mice underwent exposure via maternal drinking water supplemented with 0 (control), 2.1 (low), 16 (medium), or 32 (high) ppm Pb-acetate two weeks prior to mating through lactation. Offspring were phenotyped at ages 3, 6, and 9 months for energy expenditure, spontaneous activity, food intake, body weight, body composition, and at age 10 months for glucose tolerance. Data analyses were stratified by sex and adjusted for litter effects. Exposed females and males exhibited increased energy expenditure as compared to controls (p<0.0001 for both). In females, horizontal activity differed significantly from controls (p = 0.02) over the life-course. Overall, food intake increased in exposed females and males (p<0.0008 and p<0.0001, respectively) with significant linear trends at 9 months in females (p = 0.01) and 6 months in males (p<0.01). Body weight was significantly increased in males at the medium and high exposures (p = 0.001 and p = 0.006). Total body fat differed among exposed females and males (p<0.0001 and p<0.0001, respectively). Insulin response was significantly increased in medium exposure males (p<0.05). Perinatal Pb exposure at blood lead levels between 4.1 µg/dL and 32 µg/dL is associated with increased food intake, body weight, total body fat, energy expenditure, activity, and insulin response in mice. Physiological effects of developmental Pb exposure persist and vary according to sex and age.

Serum irisin concentration in women with gestational diabetes

Irisin is a novel myokine and adipokine which induces an increase in total body energy expenditure, improving insulin sensitivity and glucose tolerance in experimental animals. In the present study, serum irisin concentration was measured by an enzyme immunoassay in 130 women with gestational diabetes mellitus (GDM) and 140 BMI-matched patients with normal glucose tolerance (NGT). Median irisin level was significantly lower in the patients with GDM than in the NGT subjects (1703.3 [1354.8–2097.9 ng/ml] versus 1873.8 [1519.8–2294.8 ng/ml], p = 0.01); however, 3 months after childbirth its concentrations did not differ markedly between the two groups (1165.9 [872.1–1497.5] ng/ml versus 1139.0 [984.0–1376.7] ng/ml). In the whole group, irisin concentration correlated negatively with 2 h glucose level (R = −0.14, p = 0.03). In the women with NGT, irisin concentration correlated positively with ISOGTT (R = 0.22, p = 0.04) and the disposition index (DI120) (R = 0.24, p = 0.03), as well as negatively with 2 h insulin level (R = −0.23, p = 0.03) and HOMA-IR (R = −0.24, p = 0.02). Multiple regression analysis revealed that 2 h glucose and DI120 were the only variables significantly influencing serum irisin (β = 0.158, p = 0.03 and β = 0.159, p = 0.02, respectively). Our results suggest that serum irisin concentration increases markedly in pregnant women, but this increase seems to be significantly lower in patients with GDM.

Angiopoietin-like 4: An endogenous break of intestinal lipid digestion

Angiopoietin-like 4: An endogenous break of intestinal lipid digestion