Assessment of energy expenditure using doubly labeled water, physical activity by accelerometer and reported dietary intake in Japanese men with type 2 diabetes: A preliminary study.

The aim of the present study was to determine the total energy expenditure, physical activity and dietary intake of men with type 2 diabetes mellitus and control participants without type 2 diabetes mellitus who were matched for age and body mass index. The participants in the present study were 12 well-controlled type 2 diabetes mellitus patients and 10 controls, aged 40-75 years, with a body mass index <30 kg/m2 . Total energy expenditure under free-living conditions was assessed using the doubly labeled water method, and physical activity was measured using a triaxial accelerometer. Dietary intake was assessed using a self-recorded food intake diary during the measurement period. Participants were instructed to record their dietary intake over 3 days, including 2 weekdays. Total energy expenditure was not significantly different between the groups (P = 0.153), nor were energy (P = 0.969) or macronutrient intakes. In conclusion, when age and body mass index are matched, total energy expenditure and self-reported energy intake are not significantly different between type 2 diabetes mellitus patients and healthy controls.

Implications of the variation in biological 18 O natural abundance in body water to inform use of Bayesian methods for modelling total energy expenditure when using doubly labelled water.

RATIONALE: Variation in 18 O natural abundance can lead to errors in the calculation of total energy expenditure (TEE) when using the doubly labelled water (DLW) method. The use of Bayesian statistics allows a distribution to be assigned to 18 O natural abundance, thus allowing a best-fit value to be used in the calculation. The aim of this study was to calculate within-subject variation in 18 O natural abundance and apply this to our original working model for TEE calculation. METHODS: Urine samples from a cohort of 99 women, dosed with 50 g of 20% 2 H2 O, undertaking a 14-day breast milk intake protocol, were analysed for 18 O. The within-subject variance was calculated and applied to a Bayesian model for the calculation of TEE in a separate cohort of 36 women. This cohort of 36 women had taken part in a DLW study and had been dosed with 80 mg/kg body weight 2 H2 O and 150 mg/kg body weight H2 18 O. RESULTS: The average change in the δ18 O value from the 99 women was 1.14‰ (0.77) [0.99, 1.29], with the average within-subject 18 O natural abundance variance being 0.13‰2 (0.25) [0.08, 0.18]. There were no significant differences in TEE (9745 (1414), 9804 (1460) and 9789 (1455) kJ/day, non-Bayesian, Bluck Bayesian and modified Bayesian models, respectively) between methods. CONCLUSIONS: Our findings demonstrate that using a reduced natural variation in 18 O as calculated from a population does not impact significantly on the calculation of TEE in our model. It may therefore be more conservative to allow a larger variance to account for individual extremes.

Historical and contemporary stable isotope tracer approaches to studying mammalian protein metabolism.

Over a century ago, Frederick Soddy provided the first evidence for the existence of isotopes; elements that occupy the same position in the periodic table are essentially chemically identical but differ in mass due to a different number of neutrons within the atomic nucleus. Allied to the discovery of isotopes was the development of some of the first forms of mass spectrometers, driven forward by the Nobel laureates JJ Thomson and FW Aston, enabling the accurate separation, identification, and quantification of the relative abundance of these isotopes. As a result, within a few years, the number of known isotopes both stable and radioactive had greatly increased and there are now over 300 stable or radioisotopes presently known. Unknown at the time, however, was the potential utility of these isotopes within biological disciplines, it was soon discovered that these stable isotopes, particularly those of carbon (13 C), nitrogen (15 N), oxygen (18 O), and hydrogen (2 H) could be chemically introduced into organic compounds, such as fatty acids, amino acids, and sugars, and used to "trace" the metabolic fate of these compounds within biological systems. From this important breakthrough, the age of the isotope tracer was born. Over the following 80 yrs, stable isotopes would become a vital tool in not only the biological sciences, but also areas as diverse as forensics, geology, and art. This progress has been almost exclusively driven through the development of new and innovative mass spectrometry equipment from IRMS to GC-MS to LC-MS, which has allowed for the accurate quantitation of isotopic abundance within samples of complex matrices. This historical review details the development of stable isotope tracers as metabolic tools, with particular reference to their use in monitoring protein metabolism, highlighting the unique array of tools that are now available for the investigation of protein metabolism in vivo at a whole body down to a single protein level. Importantly, it will detail how this development has been closely aligned to the technological development within the area of mass spectrometry. Without the dedicated development provided by these mass spectrometrists over the past century, the use of stable isotope tracers within the field of protein metabolism would not be as widely applied as it is today, this relationship will no doubt continue to flourish in the future and stable isotope tracers will maintain their importance as a tool within the biological sciences for many years to come. © 2016 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc. Mass Spec Rev.

Application of Bayesian analysis to the doubly labelled water method for total energy expenditure in humans.

RATIONALE: The doubly labelled water (DLW) method is the reference method for the estimation of free-living total energy expenditure (TEE). In this method, where both 2 H and 18 O are employed, different approaches have been adopted to deal with the non-conformity observed regarding the distribution space for the labels being non-coincident with total body water. However, the method adopted can have a significant effect on the estimated TEE. METHODS: We proposed a Bayesian reasoning approach to modify an assumed prior distribution for the space ratio using experimental data to derive the TEE. A Bayesian hierarchical approach was also investigated. The dataset was obtained from 59 adults (37 women) who underwent a DLW experiment during which the 2 H and 18 O enrichments were measured using isotope ratio mass spectrometry (IRMS). RESULTS: TEE was estimated at 9925 (9106-11236) [median and interquartile range], 9646 (9167-10540), and 9,638 (9220-10340) kJ·day-1 for women and at 13961 (12851-15347), 13353 (12651-15088) and 13211 (12653-14238) kJ·day-1 for men, using normalized non-Bayesian, independent Bayesian and hierarchical Bayesian approaches, respectively. A comparison of hierarchical Bayesian with normalized non-Bayesian methods indicated a marked difference in behaviour between genders. The median difference was -287 kJ·day-1 for women, and -750 kJ·day-1 for men. In men there is an appreciable compression of the TEE distribution obtained from the hierarchical model compared with the normalized non-Bayesian methods (range of TEE 11234-15431 kJ·day-1 vs 10786-18221 kJ·day-1 ). An analogous, yet smaller, compression is seen in women (7081-12287 kJ·day-1 vs 6989-13775 kJ·day-1 ). CONCLUSIONS: The Bayesian analysis is an appealing method to estimate TEE during DLW experiments. The principal advantages over those obtained using the classical least-squares method is the generation of potentially more useful estimates of TEE, and improved handling of outliers and missing data scenarios, particularly if a hierarchical model is used.

Noninvasive assessment of tissue-engineered graft viability by oxygen-17 magnetic resonance spectroscopy.

Transplantation of macroencapsulated tissue-engineered grafts (TEGs) is being investigated as a treatment for type 1 diabetes, but there is a critical need to measure TEG viability both in vitro and in vivo. Oxygen deficiency is the most critical issue preventing widespread implementation of TEG transplantation and delivery of supplemental oxygen (DSO) has been shown to enhance TEG survival and function in vivo. In this study, we demonstrate the first use of oxygen-17 magnetic resonance spectroscopy (17 O-MRS) to measure the oxygen consumption rate (OCR) of TEGs and show that in addition to providing therapeutic benefits to TEGs, DSO with 17 O2 can also enable measurements of TEG viability. Macroencapsulated TEGs containing ßTC3 murine insulinoma cells were prepared with three fractional viabilities and provided with 17 O2 . Cellular metabolism of 17 O2 into nascent mitochondrial water (H217 O) was monitored by 17 O-MRS and, from the measured data, OCR was calculated. For comparison, OCR was simultaneously measured on a separate, but equivalent sample of cells with a well-established stirred microchamber technique. OCR measured by 17 O-MRS agreed well with measurements made in the stirred microchamber device. These studies confirm that 17 O-MRS can quantify TEG viability noninvasively. Biotechnol. Bioeng. 2017;114: 1118-1121. © 2016 Wiley Periodicals, Inc.

Electron spray ionization mass spectrometry and 2D 31P NMR for monitoring 18O/16O isotope exchange and turnover rates of metabolic oligophosphates.

A new method was here developed for the determination of (18)O-labeling ratios in metabolic oligophosphates, such as ATP, at different phosphoryl moieties (α-, ß-, and γ-ATP) using sensitive and rapid electrospray ionization mass spectrometry (ESI-MS). The ESI-MS-based method for monitoring of (18)O/(16)O exchange was validated with gas chromatography-mass spectrometry and 2D (31)P NMR correlation spectroscopy, the current standard methods in labeling studies. Significant correlation was found between isotopomer selective 2D (31)P NMR spectroscopy and isotopomer less selective ESI-MS method. Results demonstrate that ESI-MS provides a robust analytical platform for simultaneous determination of levels, (18)O-labeling kinetics and turnover rates of α-, ß-, and γ-phosphoryls in ATP molecule. Such method is advantageous for large scale dynamic phosphometabolomic profiling of metabolic networks and acquiring information on the status of probed cellular energetic system.

Maximal sustained levels of energy expenditure in humans during exercise.

UNLABELLED: Migrating birds have been able to sustain an energy expenditure (EE) that is five times their basal metabolic rate. Although humans can readily reach these levels, it is not yet clear what levels can be sustained for several days. PURPOSE: The study's purposes were 1) to determine the upper limits of human EE and whether or not those levels can be sustained without inducing catabolism of body tissues and 2) to determine whether initial body weight is related to the levels that can be sustained. METHODS: We compiled data on documented EE as measured by doubly labeled water during high levels of physical activity (minimum of five consecutive days). We calculated the physical activity level (PAL) of each individual studied (PAL = total EE / basal metabolic rate) from the published data. Correlations were run to examine the relationship between initial body weight and body weight lost with both total EE and PAL. RESULTS: The uppermost limit of EE was a peak PAL of 6.94 that was sustained for 10 consecutive days of a 95-d race. Only two studies reported PALs above 5.0; however, significant decreases in body mass were found in each study (0.45-1.39 kg·wk(-1) of weight loss). To test whether initial weight affects the ability to sustain high PALs, we found a significant positive correlation between TEE and initial body weight (r = 0.46, P < 0.05) but no correlation between PAL and body weight (r = 0.27, not statistically significant). CONCLUSIONS: Some elite humans are able to sustain PALs above 5.0 for a minimum of 10 d. Although significant decreases in body weight occur at this level, catabolism of body tissue may be preventable in situations with proper energy intake. Further, initial body weight does not seem to affect the sustainability of PALs.

Error assessment of nitrogen and oxygen isotope ratios of nitrate as determined via the bacterial denitrification method.

Currently, bacterial denitrification is becoming the accepted method for delta(15)N- and delta(18)O-NO(3)(-) determination. However, proper correction methods with international references (USGS32, USGS34 and USGS35) are needed. As a consequence, it is important to realize that the corrected isotope values are derived from a combination of several other measurements with associated uncertainties. Therefore, it is necessary to consider the propagated uncertainty on the final isotope value. This study demonstrates how to correctly estimate the uncertainty on corrected delta(15)N- and delta(18)O-NO(3)(-) values using a first-order Taylor series approximation. The bacterial denitrification method errors from 33 batches of 561 surface water samples varied from 0.2 to 2.1 per thousand for delta(15)N-NO(3)(-) and from 0.7 to 2.3 per thousand for delta(18)O-NO(3)(-), which is slightly wider than the machine error, which varied from 0.2 to 0.6 per thousand for delta(15)N-N(2)O and from 0.4 to 1.0 per thousand for delta(18)O-N(2)O. The overall uncertainties, which are composed of the machine error and the method error, for the 33 batches ranged from 0.3 to 2.2 per thousand for delta(15)N-NO(3)(-) and from 0.8 to 2.5 per thousand for delta(18)O-NO(3)(-). In addition, the mean corrected delta(15)N and delta(18)O values of 132 KNO(3)-IWS (internal working standard) measurements were computed as 8.4 +/- 1.0 per thousand and 25.1 +/- 2.0 per thousand, which is a slight underestimation for delta(15)N and overestimation for delta(18)O compared with the accepted values (delta(15)N = 9.9 +/- 0.3 per thousand and delta(18)O = 24.0 +/- 0.3 per thousand). The overall uncertainty of the bacterial denitrification method allows the use of this method for source identification of NO(3)(-).

Markov-chain-based heteroscedastic regression model for the analysis of high-resolution enzymatically 18O-labeled mass spectra.

The enzymatic (18)O-labeling is a useful technique for reducing the influence of the between-spectrum variability on the results of mass-spectrometry experiments. A limitation of the technique is the possibility of an incomplete labeling, which may result in biased estimates of the relative peptide abundance. We propose a Markov-chain-based regression model with heterogeneous residual variance, which corrects for the possible bias. Our method does not require extra experimental steps, as proposed in the approaches proposed previously in the literature. On the other hand, it includes some of the alternative approaches as a special case. Moreover, our modeling approach offers additional advantages over the previously developed methods, including the possibility of the analysis of multiple technical replicates for samples from different biological conditions, with an assessment of the between-spectra and biological variability.

Energy expenditure during a single-handed transatlantic yacht race.

BACKGROUND: The popularity of sports that expose people to consecutive days of high-intensity physical activity continues to increase. The ability to adequately nourish the human body to sustain the required level of competitive performance may be a key contributor to success in such events. METHODS: The energy expenditure of a male competitor in a single-handed, transatlantic race (Transat 2004) was assessed using the doubly-labelled water technique. RESULTS: Mean total daily energy expenditure (TDEE) during the race (13 days) was 14.5 MJ/day with a peak expenditure of 18.6 MJ during the most physically demanding 24-hour period. DISCUSSION: This mean TDEE was approximately 25% lower than that reported in a previous study (14.5 vs. 19.3 MJ/day) for a 13-day leg of a fully crewed offshore race. The difference in results was probably due to the fact that in the previous study, the crew operated in "watches" (work shifts), affording each crew member greater opportunity to eat, rest and sleep. Effective planning and efficient management of resources is essential to the success of the solo sailor. However, the extent to which maintenance of energy balance underpins competitive success remains to be established. To maintain energy balance during the race, a mean daily energy intake of 14.5 MJ/day was necessary for the subject in this study. However, this mean value for energy intake would have been inadequate to match the peak energy expended during the most physically demanding 24 hours of the race.

Effect of late-onset sepsis on energy expenditure in extremely premature infants.

The purpose of this study was to compare total energy expenditure (TEE) in extremely premature infants during and after an episode of sepsis. We hypothesized that TEE in the sepsis group (SEP) would be higher during the septic period and higher than an age-matched control group (CTL). We further hypothesized that the TEE of the SEP group during the recovery period would be similar to that of the CTL group. The doubly labeled water method was used to determine TEE in both groups. Infant characteristics were as follows: SEP group, n = 10, gestation = 26 +/- 1 wk, birth weight = 854 +/- 218 g; CTL group, n = 10, gestation = 26 +/- 1 wk, birth weight = 880 +/- 158 g. TEE of the SEP group during the septic period was significantly greater than during the recovery period (96 +/- 25 kcal/kg/d versus 55 +/- 17 kcal/kg/d) and significantly greater than the CTL group during the first study period (96 +/- 25 kcal/kg/d versus 67 +/- 12 kcal/kg/d). TEE in the SEP group during the recovery period was similar to the CTL group. These increases in TEE may contribute to impaired growth and need to be considered when providing nutritional support for extremely premature infants.

Assessment of the amount of body water in the Red Knot (Calidris canutus): an evaluation of the principle of isotope dilution with 2H, (17)O, and (18)O as measured with laser spectrometry and isotope ratio mass spectrometry.

We have used the isotope dilution technique to study changes in the body composition of a migratory shorebird species (Red Knot, Calidris canutus) through an assessment of the amount of body water in it. Birds were quantitatively injected with a dose of water with elevated concentrations of 2H, (17)O, and (18)O. Thereafter, blood samples were taken and distilled. The resulting water samples were analysed using an isotope ratio mass spectrometry (for 2H and (18)O only) and a stable isotope ratio infrared laser spectrometry (2H, (17)O, and (18)O) to yield estimates of the amount of body water in the birds, which in turn could be correlated to the amount of body fat. Here, we validate laser spectrometry against mass spectrometry and show that all three isotopes may be used for body water determinations. This opens the way to the extension of the doubly labelled water method, used for the determination of energy expenditure, to a triply labelled water method, incorporating an evaporative water loss correction on a subject-by-subject basis or, alternatively, the reduction of the analytical errors by statistically combining the (17)O and (18)O measurements.

Total energy expenditure estimated using a foot-contact pedometer.

BACKGROUND: Total energy expenditure (TEE) assessment using pedometers provide an easy and less expensive method than doubly labeled water (DLW). This study assessed TEE by a new pedometry method (TEEpedo) compared to the doubly labeled water method (TEEdlw). MATERIAL/METHODS: Shipboard sailors (7 men, age: 23.0+/-3.9 yrs; ht: 180.2+/-6.5 cm; wt: 83.8+/-11.8 kg, and 10 women, age: 24.7+/-4.4 yrs; ht: 165.2+/-8.0 cm; wt: 63.5+/-14.0 kg) (Mean +/-SD) were studied for 8 days. The energy cost of activity was estimated using (a) total body weight, (b) foot-ground contact times [Tc] during running, walking, and non-exercise activity [NEAT], and (c) the known proportion of time spent in each activity category. Resting metabolic rate (RMR) was estimated from lean body mass. RESULTS: TEEPEDO was calculated as: TEEpedo (MJ) = (1440 x [%Run Time x ((0.0761 x [Total Body Weight/TcRun]) - 7.598) +%Walk Time x ((0.056 x [Total Body Weight/TcWalk]) - 2.938) + (%NEAT Time x 0.1 x [RMR/Minute])] + RMR)/239. This method, explained 79% of the variance of TEEpedo with a 95% confidence interval of +/-0.81 MJ/day, relative to TEEdlw (12.55+/-3.3MJ/day). Mean TEEpedo (12.65+/-3.1 MJ/day) did not differ from mean TEEdlw (p=0.95). CONCLUSIONS: At TEEs >14 MJ/day, the TEEpedo method underestimated actual TEE, possibly due to unaccounted for upper body exercise. At more moderate TEEs of 9 to 14 MJ/day, the Tc pedometry method provided accurate estimates of TEE.

Centile reference charts for total energy expenditure in infants from 1 to 12 months.

BACKGROUND: A knowledge of energy expenditure in infancy is required for the estimation of recommended daily amounts of food energy, for designing artificial infant feeds, and as a reference standard for studies of energy metabolism in disease states. OBJECTIVES: The objectives of this study were to construct centile reference charts for total energy expenditure (TEE) in infants across the first year of life. METHODS: Repeated measures of TEE using the doubly labeled water technique were made in 162 infants at 1.5, 3, 6, 9 and 12 months. In total, 322 TEE measurements were obtained. The LMS method with maximum penalized likelihood was used to construct the centile reference charts. Centiles were constructed for TEE expressed as MJ/day and also expressed relative to body weight (BW) and fat-free mass (FFM). RESULTS: TEE increased with age and was 1.40,1.86, 2.64, 3.07 and 3.65 MJ/day at 1.5, 3, 6, 9 and 12 months, respectively. The standard deviations were 0.43, 0.47, 0.52,0.66 and 0.88, respectively. TEE in MJ/kg increased from 0.29 to 0.36 and in MJ/day/kg FFM from 0.36 to 0.48. CONCLUSIONS: We have presented centile reference charts for TEE expressed as MJ/day and expressed relative to BW and FFM in infants across the first year of life. There was a wide variation or biological scatter in TEE values seen at all ages. We suggest that these centile charts may be used to assess and possibly quantify abnormal energy metabolism in disease states in infants.

Validation of three alternative methods to measure total energy expenditure against the doubly labeled water method for older Japanese men.

In a previous study using young Japanese men as subjects, Ebine et al. found that accelerometer (AC) represents a promising technique for measuring free-living total energy expenditure (TEE) when compared to activity records (AR) and heart rate monitoring (HR). Thus, the present study was designed to validate the use of an AC and to determine whether or not the previous findings regarding the three alternative field methods (AC, AR, and HR) could be extended to older Japanese men (n = 24; mean +/- SD age 48 +/- 10 y, body mass index 23.1 +/- 2.7 kg/m2 and body fat 18.7 +/- 4.8%). TEE values obtained over a 3 d period by AR, HR, and AC (3dAC), and AC over a 14 d period (14dAC) were simultaneously validated against TEE measured by the doubly labeled water (DLW) method applied within a 14 d period. TEE values obtained by AR, HR, 3dAC, and 14dAC ranged from 1,750 to 3,447 kcal/d, 1,691 to 5,286 kcal/d, 1,716 to 2,765 kcal/d, and 1,700 to 2,855 kcal/d, respectively. Expenditures obtained by HR were similar to those obtained using the DLW method, with a mean difference of 57 +/- 603 kcal/d (2%), but those obtained using AR, 3dAC, and 14dAC differed substantially from the DLW method, with mean differences of -335 +/- 289 kcal/d (12%), -542 +/- 249kcal/d (-19%), and -566 +/- 223kcal/d (-20%), respectively. AR, HR, 3dAC, and 14dAC were significantly correlated with the DLW method, with r values of 0.76 (p < 0.0001), 0.67 (p < 0.001), 0.78 (p < 0.0001), and 0.83 (p < 0.0001), respectively. Intra-individual variation indicated by the coefficient of variation (CV) was significantly higher for HR (15 +/- 11%, p < 0.001) than for AR (7 +/- 4%), 3dAC (7 +/- 5%), and 14dAC (8 +/- 31%). The same findings were obtained using Bland and Altman plots at the population level. Interestingly, 3dAC and 14dAC were significantly correlated with r = 0.97 (p < 0.0001), with a lower mean difference of 24 kcal/d. These results suggest that, same as the previous study, AC is superior to HR in estimating TEE, and seems to be satisfactory for estimation at both group and individual levels, particularly for large-scale studies of older individuals when compared to the DLW method. However, some modifications of the AC method may be needed to compensate for the underestimation of TEE.

Energy intake by multiple pass 24 h recall and total energy expenditure: a comparison in a representative sample of 3-4-year-olds.

The accuracy of the multiple pass 24 h recall for assessment of habitual energy intake in pre-school children is unclear. The primary aim of this study was to assess its accuracy by comparison with measurement of total energy expenditure by doubly-labelled water in a representative sample of forty-one 3-4-year-olds. The recall method was well tolerated by subjects and was administered quickly and easily. However, it produced estimates of energy intake which significantly exceeded measures of total energy expenditure from doubly-labelled water, mean paired difference 660 kJ/d (P<0.01). Agreement between the two methods was poor at the individual level: limits of agreement 660+/-3018 kJ/d. Error and imprecision in both methods contribute to individual differences, but the present study suggests that the multiple pass 24 h recall does not provide accurate estimates of dietary energy intake in individual children.