Indirect Calorimetry Measurements Research Articles

Tangzhiping Decoction Improves Glucose and Lipid Metabolism and Exerts Protective Effects Against White Adipose Tissue Dysfunction in Prediabetic Mice.

Prediabetes, characterized by a series of metabolic abnormalities, increases the risk of diabetes and cardiovascular diseases. Tangzhiping (TZP), a clinically validated traditional Chinese medicine formula, is used to treat impaired glucose tolerance. However, the underlying mechanism of TZP in intervening prediabetes is not fully elucidated. The current study aimed to evaluate the protective effect of TZP against prediabetes mice and explore its potential mechanism. After establishing a prediabetic animal model through 12 weeks of high-fat diet (HFD) feeding, mice were subjected to TZP for 8 weeks. Various parameters related to body weight, glucose and lipid metabolism, and insulin sensitivity were measured. Histopathological examinations observed adipose cell size and liver lipid deposition. The Sable Promethion system assessed energy metabolism activity. Transcriptomic analysis of Epididymal white adipose tissue (EWAT) identified enriched pathways and genes. The key genes in the enriched pathways were identified through RT-PCR. Our data revealed that the administration of TZP reduced body weight and fat mass in a prediabetes mouse model. TZP normalized the glucose and insulin levels, improved insulin resistance, and decreased plasma TC and FFA. The alleviation of adipose tissue hypertrophy and lipid deposition by TZP was demonstrated through pathological examination. Indirect calorimetry measurements indicated a potential increase in VO2 and EE levels with TZP. The results of EWAT transcription showed that TZP reversed pathways and genes related to inflammation and catabolic metabolism. RT-PCR demonstrated that the mRNA expression of inflammation and lipolysis, including Tlr2, Ccr5, Ccl9, Itgb2, Lipe, Pnpla2, Cdo1, Ces1d, Echs1, and Acad11, were changed by TZP treatment. TZP effectively alleviates obesity, impaired glucose and lipid metabolism, and insulin resistance. The effect of TZP might be associated with the regulation of gene expression in dysfunctional adipose tissue.

Impact of date-based energy bar intake on postprandial appetite, metabolism and thermogenesis

Research studies suggest that date-palm (Phoenix dactylifera L.) fruits provide a superior nutritional and health benefits, compared to other fruits (1). They are rich source of many essential nutrients including carbohydrates, dietary fibre, vitamins, minerals, phytochemicals, and antioxidants. The date palm fruits are produced in many countries around the world and about 10-15% of the total production is lost or sold extremely at low prices (2, 3). Despite these, date fruits have been rarely used as an ingredient in commercially available energy bars. The aim of this study is to investigate the impact of newly formulated date-based energy bar (DBEB) (4) intake on subjective appetite, postprandial metabolism, energy substrate oxidation and diet-induced thermogenesis (DIT).Twenty-seven healthy male adults (mean ± SD, aged 20.8 ± 3.5 years with body weight of 66 ± 8 kg) participated in a randomised crossover design study. Each participant conducted two experimental arms and was investigated prior to (baseline) and for three-hours after consumption of either a date- based energy bar (DBEB) or an isocaloric and macronutrient matched mixed fruit-based energy bar (FBEB) as control arm. The DBEB contained significantly less fructose and glucose, but more sucrose and fibre than FBEB. Both experimental arms involved blood sampling, subjective appetite, and indirect calorimetry measurements. At the end of each experiment, an ad libitum buffet meal was provided. Data analysis used descriptive statistics, paired t-test, and two-way ANOVA.Time-averaged composite appetite and satiety scores were not significantly different between control (FBEB) and DBEB arms. Energy intake during ad libitum buffet was also not different between arms. Metabolic rate measured at baseline and during post-ingestion of the bars were not significantly different between FBEB and DBEB arms (arm effect, P>0.05). Thermic effect of bars calculated as percentage increase in metabolic rate above RMR during whole postprandial duration was (mean ± SE) 9.5 ± 1.6 % in DBEB arm and 8.7 ± 1.3 % in the FBEB arm (arm effect, P>0.05). Rates of carbohydrate and fat oxidation were also not different between the two arms (arm effect, P>0.05) Time-averaged concentrations of blood glucose, insulin and triglycerides were similar between the study arms.The obtained results suggest that energy bars based on dates or mixed fruits produce similar effects on postprandial appetite, fat and carbohydrate oxidation, thermic effect and cardiometabolic risk factors. Date fruits can be used as rich source for carbohydrate and energy. However, future research should investigate the impact of date-based energy bars on antioxidant capacity and other health related markers.

Objective Assessment of Physical Activity at Home Using a Novel Floor-Vibration Monitoring System: Validation and Comparison With Wearable Activity Trackers and Indirect Calorimetry Measurements.

The self-monitoring of physical activity is an effective strategy for promoting active lifestyles. However, accurately assessing physical activity remains challenging in certain situations. This study evaluates a novel floor-vibration monitoring system to quantify housework-related physical activity. This study aims to assess the validity of step-count and physical behavior intensity predictions of a novel floor-vibration monitoring system in comparison with the actual number of steps and indirect calorimetry measurements. The accuracy of the predictions is also compared with that of research-grade devices (ActiGraph GT9X). The Ocha-House, located in Tokyo, serves as an independent experimental facility equipped with high-sensitivity accelerometers installed on the floor to monitor vibrations. Dedicated data processing software was developed to analyze floor-vibration signals and calculate 3 quantitative indices: floor-vibration quantity, step count, and moving distance. In total, 10 participants performed 4 different housework-related activities, wearing ActiGraph GT9X monitors on both the waist and wrist for 6 minutes each. Concurrently, floor-vibration data were collected, and the energy expenditure was measured using the Douglas bag method to determine the actual intensity of activities. Significant correlations (P<.001) were found between the quantity of floor vibrations, the estimated step count, the estimated moving distance, and the actual activity intensities. The step-count parameter extracted from the floor-vibration signal emerged as the most robust predictor (r2=0.82; P<.001). Multiple regression models incorporating several floor-vibration-extracted parameters showed a strong association with actual activity intensities (r2=0.88; P<.001). Both the step-count and intensity predictions made by the floor-vibration monitoring system exhibited greater accuracy than those of the ActiGraph monitor. Floor-vibration monitoring systems seem able to produce valid quantitative assessments of physical activity for selected housework-related activities. In the future, connected smart home systems that integrate this type of technology could be used to perform continuous and accurate evaluations of physical behaviors throughout the day.

Accuracy of the SenseWear Armband during Short Bouts of Exercise.

A goal of mobile monitoring is to approximate metabolic energy expenditure (EE) during activities of daily living and exercise. Many physical activity monitors are inaccurate with respect to estimated EE and differentiating between activities that occur over short intervals. The objective of our study was to assess the validity of the SenseWear Armband (SWA) compared to indirect calorimetry (IC) during short intervals of walking and running. Twenty young, fit participants walked (preferred speed) and ran (75%, 85%, and 95% of predicted VO2max run speeds) on a treadmill. EE estimates from IC, SWA, and prediction equations that used the SWA, speed, and heart rate were examined during each 4 min interval and across the whole protocol (Total). The level of significance was p < 0.05. The SWA overestimated EE relative to IC by 1.62 kcal·min-1 while walking and 1.05 kcal·min-1 while running at 75%. However, it underestimated EE at the 85% (0.05 kcal·min-1) and 95% (0.92 kcal·min-1) speeds, but not significantly, and overestimated total EE by 28.29 kcal. Except for walking, our results suggest that the SWA displayed a good level of agreement (ICC = 0.76 to 0.84) with IC measures. Activity-specific algorithms using SWA, speed, and heart rate improved EE estimates, based on the standard error of the estimates, but perhaps not enough to justify extra sensors. The SWA may enable EE estimation of locomotion outside the laboratory, including those with short bouts of high intensity activity, but continued development of the SWA, or devices like it, is needed to enable accurate monitoring.

Metabolic Costs of Walking with Weighted Vests.

The US Army Load Carriage Decision Aid (LCDA) metabolic model is used by militaries across the globe and is intended to predict physiological responses, specifically metabolic costs, in a wide range of dismounted warfighter operations. However, the LCDA has yet to be adapted for vest-borne load carriage, which is commonplace in tactical populations, and differs in energetic costs to backpacking and other forms of load carriage. The purpose of this study is to develop and validate a metabolic model term that accurately estimates the effect of weighted vest loads on standing and walking metabolic rate for military mission-planning and general applications. Twenty healthy, physically active military-age adults (4 women, 16 men; age, 26 ± 8 yr old; height, 1.74 ± 0.09 m; body mass, 81 ± 16 kg) walked for 6 to 21 min with four levels of weighted vest loading (0 to 66% body mass) at up to 11 treadmill speeds (0.45 to 1.97 m·s -1 ). Using indirect calorimetry measurements, we derived a new model term for estimating metabolic rate when carrying vest-borne loads. Model estimates were evaluated internally by k -fold cross-validation and externally against 12 reference datasets (264 total participants). We tested if the 90% confidence interval of the mean paired difference was within equivalence limits equal to 10% of the measured walking metabolic rate. Estimation accuracy, precision, and level of agreement were also evaluated by the bias, standard deviation of paired differences, and concordance correlation coefficient (CCC), respectively. Metabolic rate estimates using the new weighted vest term were statistically equivalent ( P < 0.01) to measured values in the current study (bias, -0.01 ± 0.54 W·kg -1 ; CCC, 0.973) as well as from the 12 reference datasets (bias, -0.16 ± 0.59 W·kg -1 ; CCC, 0.963). The updated LCDA metabolic model calculates accurate predictions of metabolic rate when carrying heavy backpack and vest-borne loads. Tactical populations and recreational athletes that train with weighted vests can confidently use the simplified LCDA metabolic calculator provided as Supplemental Digital Content to estimate metabolic rates for work/rest guidance, training periodization, and nutritional interventions.

An evaluation of intensive care nurses' performance of indirect calorimetry measurements.

Indirect calorimetry (IC) is the gold standard to monitor energy expenditure in critically ill patients. In several intensive care units (ICUs), nurses are responsible for carrying out the measurements. The aim of this study was to assess nurses' perception of their involvement in IC. This was a prospective survey conducted in the surgical ICU of a French university hospital after 18 months of use of the Q-NRG + ® calorimeter (COSMED©, Italy). All nurses who have used the calorimeter in the previous 6 months in this ICU were questioned through a questionnaire about their theoretical and practical knowledge and experience in using it. The participation rate was 93% (28/30 surveyed). All the respondents understood the objectives of performing an IC and 23 of them (82%) had used the device at least once in the previous 6 months. All the users thought it was pertinent that ICU nurses were in charge of the IC measurements, 16 of them (70%) reported having been formally trained, mostly by a colleague, and 17 (77%) felt comfortable with the device after 2 to 5 uses. The five non-users (8%) did not have the opportunity to do so. Theoretical and practical knowledge could be improved as only 5 of the users (22%) declared to know the main criteria of reliability of the IC measurement and 4 of them (18%) declared to know the maintenance and cleaning protocol of the device. Nurses quickly felt comfortable with the Q-NRG + ® in this ICU. Formal initial and ongoing training of all staff completing IC is essential to perform IC measurements safely and to obtain reliable and interpretable results in practice. Involving the nursing team in nutritional care, even if it is technical, seems to bring satisfaction in terms of overall patient care.

The screening and monitoring of type 2 diabetes by indirect calorimetry

An increasing amount of study is being dedicated to the identification of biomarkers associated with type 2 diabetes, with particular emphasis on the field of Metabonomics. To screen and prevent type 2 diabetes, indirect calorimetry measures real-time oxygen consumption (V_02) and carbon dioxide production (V_C02) and measures an individuals metabolic tendency which is the ratio of glucose and fat as energy substrate for a specific activity. A person with aberrant glucose metabolism after measurement may have type 2 diabetes. Adjusting food intake helps type 2 diabetics control blood glucose. Now, type 2 diabetes become personalized. In other words, type 2 diabetes needs to be analysed case by case. The population can be divided into different categories in terms of metabolic adjustment. After classification, indirect calorimetry can be used in clinical research whose purposes are to screen, prevent and treat type 2 diabetes. This paper uses literature reviews to summarize the genetic factors and environmental factors of type 2 diabetes, explain the necessity and limitations for screening, monitoring, preventing and curing type 2 diabetes, and the reasons for calorimetry can screen and monitor type 2 diabetes and how to calculate the percentage of energy substrates for a certain activity.

Can a modified ketogenic diet be a nutritional strategy for patients with McArdle disease? Results from a randomized, single-blind, placebo-controlled, cross-over study

McArdle disease is caused by myophosphorylase deficiency leading to blocked glycogenolysis in skeletal muscle. Consequently, individuals with McArdle disease have intolerance to physical activity, muscle fatigue, and pain. These symptoms vary according to the availability of alternative fuels for muscle contraction. In theory, a modified ketogenic diet (mKD) can provide alternative fuels in the form of ketone bodies and potentially boost fat oxidation. This randomized, single-blind, placebo-controlled, cross-over study aimed to investigate if a mKD improves exercise capacity in individuals with McArdle disease. Participants were randomized to follow a mKD (75-80% fat, 15% protein, 5-10% carbohydrates) or placebo diet (PD) first for three weeks, followed by a wash-out period, and then the opposite diet. The primary outcome was change in heart rate during constant-load cycling. Secondary outcomes included change in plasma metabolites, perceived exertion, indirect calorimetry measures, maximal exercise capacity, and patient-reported outcomes. Fifteen out of 20 patients with genetically verified McArdle disease completed all study visits, and 14 were included in the data analyses. We found that the mKD induced a metabolic shift towards increased fat oxidation (∼60% increase), and a 19-fold increase in plasma β-hydroxybutyrate (p<0.05). The mKD did not improve heart rate responses during constant-load cycling but did improve patient-reported outcomes and maximal exercise capacity (∼20% increase) compared to the PD. The mKD did not alleviate all McArdle disease-related symptoms but did induce some positive changes. To date, no satisfactory treatment options exist other than exercise training. To that end, a mKD can be a possible nutritional strategy for some individuals with McArdle disease who are motivated to undertake a restrictive diet. clinical trials.gov: NCT04044508.

Indirect calorimetry measurements in critically ill patients: The 1st data from the Republic of Ireland

Indirect calorimetry measurements in critically ill patients: The 1st data from the Republic of Ireland

Two-hour indirect calorimetry measurement as a predictor of 24-hour energy expenditure in critically ill surgical patients: A longitudinal study.

Measuring energy expenditure (EE) by indirect calorimetry (IC) has become the gold standard tool for critically ill patients to define energy targets and tailor nutrition. Debate remains as to the optimal duration of measurements or the optimal time of day in which to perform IC. In this retrospective longitudinal study, we analyzed results of daily continuous IC in 270 mechanically ventilated, critically ill patients admitted to the surgical intensive care unit in a tertiary medical center and compared measurements performed at different hours of the day. A total of 51,448 IC hours was recorded, with an average 24-h EE of 1523 ± 443 kcal/day. Night shift (00:00-8:00) was found to have significantly lower EE measurements (mean, 1499 ± 439 kcal/day) than afternoon (16:00-00:00; mean, 1526 ± 435 kcal/day) and morning (8:00-16:00; mean, 1539 ± 462 kcal/day) measurements (P < 0.001 for all). The bi-hourly time frame that most closely resembled the daily mean was 18:00-19:59, with a mean of 1521 ± 433 kcal/day. Daily EE measurements of the continuous IC at days 3-7 of admission showed a trend toward a daily increase in 24-h EE, but the difference was not statistically significant (P = 0.081). Periodic measurements of EE can differ slightly when performed at various hours of the day, but the error range is small and may not necessarily have a clinical impact. When continuous IC is not available, a 2-h EE measurement between 18:00 and 19:59 can serve as a reasonable alternative.

Resting energy expenditure measured by indirect calorimetry in mechanically ventilated patients during ICU stay and post-ICU hospitalization: A prospective observational study

PurposeThe metabolic course during and after critical illness is unclear. We performed repeated indirect calorimetry (IC) measurements during ICU- and post-ICU hospitalization to determine resting energy expenditure (REE). MethodsProspective observational design. In ventilated ICU patients, IC measurements were performed every three days until hospital discharge. Measured REE as predicted by the Harris-Benedict equation (HBE-REE) and 25 kcal/adjusted body weight/day (25-REE) were compared. ResultsIn 56 patients (38% females, 71[13]years, BMI 29(27;31)kg/m2), 189 ICU IC measurements were performed. Measured REE did not differ from HBE-REE at ICU admission, but was lower than 25-REE. Measured REE was increased compared to baseline on ICU-admission-day four (29(29–30)kcal/kg/day; mean difference 3.1(1.4–4.9)kcal/kg/day, p < 0.001) and thereafter during ICU admission. During post-ICU ward stay, 44 measurements were performed in 23 patients, showing a higher mean REE than during ICU stay (33(31–35)kcal/kg/day; mean difference 2.6(1.2–3.9)kcal/kg/day, p < 0.001). The REE in the ICU and ward was >110% of HBE-REE from day four onwards. ConclusionsCritically ill mechanically ventilated patients were shown to have a resting energy expenditure (REE) > 110% of predicted REE on ICU admission day four and thereafter. Indirect calorimetry measurements suggest that the mean energy requirements during post-ICU hospitalization are higher than those in the ICU.

DYNAMIC METABOLIC CHANGES OBSERVED IN AN LPS-INDUCED SYSTEMIC INFLAMMATION RAT MODEL USING CONTINUOUS LONG-TERM INDIRECT CALORIMETRY EXPERIMENTS.

Background : Nutritional management is crucial for severely ill patients. Measuring metabolism is believed to be necessary for the acute sepsis phase to accurately estimate nutrition. Indirect calorimetry (IDC) is assumed to be useful for acute intensive care; however, there are few studies on long-term IDC measurement in patients with systemic inflammation. Methods : Rats were categorized into the LPS received or control groups; LPS rats were categorized into underfeeding (UF), adjusted feeding (AF), and overfeeding (OF) groups. Indirect calorimetry measurement was performed until 72 or 144 h. Body composition was measured at -24 and 72 or 144 h, and tissue weight was measured at 72 or 144 h. Results : Low energy consumption and loss of diurnal variation of resting energy expenditure were observed in the LPS group compared with the control group until 72 h, after which the LPS group recovered. The resting energy expenditure in the OF group was higher than that in the UF and AF groups. In the first phase, low energy consumption was observed in all groups. In the second and third phases, higher energy consumption occurred in the OF group than in the UF and AF groups. In the third phase, diurnal variation recovered in all groups. Muscle atrophy caused body weight loss, but fat tissue loss did not occur. Conclusions : We observed metabolic changes with IDC during the acute systemic inflammation phase owing to differences in calorie intake. This is the first report of long-term IDC measurement using the LPS-induced systemic inflammation rat model.

Measuring energy requirements during pulmonary exacerbations of cystic fibrosis using indirect calorimetry

ObjectiveThe energy demands of individuals with cystic fibrosis (CF) vary depending on pancreatic function, body composition, lung function, and clinical status. In clinical practice, predictive equations are used to determine energy requirements yet do not reliably account for these factors. Research regarding energy requirements during CF pulmonary exacerbation (CFPEx) and clinical stability is conflicting. The aim of this study was to investigate potential within-individual changes in measured resting energy expenditure (mREE) using indirect calorimetry (IC) at the commencement and completion of intravenous antibiotic treatment (IVABx) for CFPEx and during clinical stability. Secondary aims were to investigate potential differences between predicted resting energy expenditure (pREE) using Schofield equation and correlations between clinical factors with mREE. MethodsBody composition using bioimpedance analysis and mREE were conducted at three time points: commencement of IVABx; completion of IVABx; and clinically stable period thereafter. ResultsTwenty-eight adults with CF completed at least one valid IC measurement. No significant within-person changes in mREE and body composition parameters were observed across time points. The mREE was positively correlated with fat-free mass (kg; r = 0.6; P = 0.008). The mREE was significantly higher than pREE at all time points with the mREE/pREE ratio elevated at time point 1:118% ± 19.5%; time point 2: 112% ± 13.2%; and time point 3: 122 ± 14.3%. ConclusionThe mREE remained stable during CFPEx and clinical stability. The pREE underestimated mREE and application of injury factor adjustment of 110% to 130% could potentially account for this discrepancy. The potential role of IC and body composition in individualizing CF nutritional assessment and prescription requires further exploration.

Effects of physical exercise on glycemic metabolism, aerobic capacity and structure of brown adipose tissue in diabetic animals

The ability of brown adipose tissue (BAT) and aerobic physical exercise (AET) to improve energy metabolism is widely known. Since AET has been used as an insulin- sensitizing therapy for diabetes, here we tested whether the effects of AET on the glycemic metabolism and aerobic capacity of diabetic animals are accompanied by structural changes in BAT. Adult male C57BL6/J mice were assigned into groups: non-diabetic sedentary (NDS, n=6), non-diabetic trained (NDT, n=6), diabetic sedentary (DS, n=4) and diabetic trained (DT, n=7). Diabetes was induced by high-fat and -fructose diet and intraperitoneal injection of streptozotocin (120 mg/g). AET consisted of 8-wk running session of 60 min at 60% of maximal speed, 5 days/wk. Experimental procedures were approved by Ethics Committees from Faculty of Medicine and from School of Arts, Science and Humanities of University of São Paulo (#1473/2020 and #001/2020, respectively). Initial body weight (BW) did not differ among groups, however the DS and DT groups had lower final BW compared with NDS. The BW gain of DS group was lower compared with NDS group. Food consumption (Kcal/animal/day) was higher in DT group compared with NDS and NDT. The DS and DT groups had higher fasting blood glucose, and DS group had greater area under the curve on the glucose tolerance test than the NDS and NDT groups. Indirect calorimetry measurement at rest revealed no difference in the variables oxygen uptake (VO2), carbon dioxide expiration (VCO2), respiratory exchange ratio (RER), energy expenditure (EE), carbohydrate and fat oxidation among groups. During maximal exercise test, NDT and DT increased the time to exhaustion, maximal speed, intensity corresponding to the VO2máx (iVO2) compared with NDS and DS. An increase in VO2máx and VCO2máx was observed in NDT group compared with DS and DT group. No differences were observed in the weight of white adipose tissue depots (retroperitoneal, periepididymal and subcutaneous), interscapular brown adipose tissue (iBAT), skeletal muscle (gastrocnemius and soleus), and other organs (heart, lung, and kidney). Morphometric analysis of the iBAT revealed that the area, diameter, volume, mass, frequency of lipid droplet distribution by size (small, medium, large, and very large) and amount of lipid droplets did not differ among groups, however, collagen deposition in the iBAT increased in the DS and DT groups compared with NDS group. In conclusion, the AET-induced improvement in glucose tolerance and aerobic capacity in diabetic animals is not accompanied by changes in morphometry and collagen deposition in the iBAT. This study was supported by grants from the São Paulo Research Foundation (FAPESP) #2020/15748-4 and #2020/12005-0. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A homeostatic metabolic role for estrogen receptor α in the subfornical organ

Approximately 70% of American adults are considered overweight or obese putting them at increased risk for metabolic syndrome, which includes a constellation of abnormalities that can result in cardiovascular disease, type II diabetes, and fatty liver. Sexual dimorphism in metabolic syndrome is clearly established. Adult men display increased prevalence of metabolic syndrome comorbidities when compared to fertile women. However, post-menopause, the incidence of metabolic syndrome in women significantly increases. It is widely proposed that the increased post-menopausal incidence of metabolic syndrome is due, in part, to estrogen deficiency. Within the brain, estrogen regulates metabolism primarily through actions on estrogen receptor alpha (ERα). While a major emphasis has been placed on hypothalamic nuclei, whether there is a distributed neural network of ERα that works through autonomic and endocrine actions to influence metabolism remains incompletely defined. We have recently shown a critical role for the subfornical organ (SFO), a circumventricular region that lies outside the blood barrier, in the regulation of peripheral metabolism in males. However, whether this brain nucleus and further estrogen signaling within this region is involved the control of metabolism in females is unknown. Taken together, we hypothesized that ERα in the SFO may regulate peripheral metabolism in female mice during obesity. To investigate this, 6 wk old female ESRα flox mice received targeted SFO microinjections of AAV-Cre-GFP and titer matched control AAV-LacZ-GFP. Following 2 wks of viral incorporation, mice were fed a high fat diet (HFD; 60% kcal from fat) for 10 weeks. Indirect calorimetry measurements indicated that SFO ERα removal resulted inhyperphagic behavior during HFD feeding (Cumulative food intake: 27.4±2.7 g vs 37.5±3.3 g, GFP vs. Cre, n=7-8, p&lt;0.05) that was counterbalanced by increased energy expenditure (0.46±0.02 vs. 0.51±0.02 kcal/hr, GFP vs. Cre, n=7-8, p&lt;0.05) resulting in no influence on body weight (ΔBody weight: 18.9±3.2 vs. 20.3±1.6 g, GFP vs. Cre, n=4, p&gt;0.05) or adiposity. Interestingly, SFO ERα knockdown exacerbated hepatic steatosis during diet-induced obesity (Oil Red staining, 8.8±1.9 vs 18.8±2.8 au x 107, GFP vs. Cre, n=7-8, p&lt;0.05), although this was in contrast to improved whole-body glucose tolerance in response to an i.p. glucose load (6.1±0.2 vs 4.7±0.5 AUC x 104, GFP vs. Cre, n=5-6, p&lt;0.05) and upregulation of skeletal muscle long-chain fatty acid b-oxidation genes (e.g. Cpt1: 2.3±0.7 Cre fold GFP, n=4-5, p&lt;0.05). Finally, deletion of SFO ERα was associated with a reduction in circulating estrogen during obesity (80.0±4.3 vs 45.2±12.5 pg/mL, GFP vs. Cre, n=3-4, p=0.06). Collectively, these findings indicate that SFO ERα may differentially regulate target organs during obesity and points to a complex set of interactions whereby SFO estrogen signaling can both positively and negatively regulate peripheral metabolism. R01DK117007, R01HL141393, F31 NIDDK12829388 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Measuring Energy Requirements of Traumatic Brain Injury Patients in Pediatric Intensive Care With Indirect Calorimetry: A Comparison With Empiric Methods.

Energy requirements following moderate or severe pediatric traumatic brain injury (TBI) have not been fully elucidated. Indirect calorimetry (IC) is the gold standard for measuring resting energy expenditure (MREE) in PICU. However, technical complexity limits its use. We aimed to determine whether MREE differs from standard of care energy estimation and delivery in a cohort of pediatric patients following moderate to severe TBI during PICU admission. Retrospective case series study. Single-center, 16-bed general PICU in Canada between May 2011 and January 2019. Children (0-18 yr) admitted to a PICU for moderate (Glasgow Coma Scale [GCS] 9-12) to severe TBI (GCS < 9) and had an IC study performed while mechanically ventilated. None. During the study period, 245 patients were admitted with the diagnosis of trauma with TBI. The study includes a convenience sample of 26 patients with severe ( n = 23) and moderate ( n = 3) TBI who underwent a total of 34 IC measurements. MREE varied considerably from 29% to 144% of predicted energy expenditure. Using Bland-Altman comparative analysis, neither Schofield nor World Health Organization predictive equations were in agreement with MREE. Only one measurement revealed that the patient was appropriately fed (energy provided in nutrition support was within 10% of MREE); 10 (38%) measurements revealed overfeeding and 15 (58%) underfeeding at the time of testing. The present study adds to the small body of literature highlighting the limitations of predictive equations to evaluate energy requirements following moderate to severe pediatric TBI. IC, when feasible, should be used as the preferred method to orient PICU teams to feed such vulnerable patients.

Single-FiO2 lung modelling with machine learning: a computer simulation incorporating volumetric capnography

We investigated whether machine learning (ML) analysis of ICU monitoring data incorporating volumetric capnography measurements of mean alveolar PCO2 can partition venous admixture (VenAd) into its shunt and low V/Q components without manipulating the inspired oxygen fraction (FiO2). From a 21-compartment ventilation / perfusion (V/Q) model of pulmonary blood flow we generated blood gas and mean alveolar PCO2 data in simulated scenarios with shunt values from 7.3% to 36.5% and a range of FiO2 settings, indirect calorimetry and cardiac output measurements and acid- base and hemoglobin oxygen affinity conditions. A ‘deep learning’ ML application, trained and validated solely on single FiO2 bedside monitoring data from 14,736 scenarios, then recovered shunt values in 500 test scenarios with true shunt values ‘held back’. ML shunt estimates versus true values (n = 500) produced a linear regression model with slope = 0.987, intercept = -0.001 and R2 = 0.999. Kernel density estimate and error plots confirmed close agreement. With corresponding VenAd values calculated from the same bedside data, low V/Q flow can be reported as VenAd—shunt. ML analysis of blood gas, indirect calorimetry, volumetric capnography and cardiac output measurements can quantify pulmonary oxygenation deficits as percentage shunt flow (V/Q = 0) versus percentage low V/Q flow (V/Q > 0). High fidelity reports are possible from analysis of data collected solely at the operating FiO2.

Accuracy of Resting Metabolic Rate Prediction Equations in Sport Climbers

Resting metabolic rate (RMR) represents the energy required to maintain vital body functions. In dietary practice, RMR is determined by predictive equations on the basis of using body weight or fat-free mass. Our study aimed to assess whether predictive equations used to estimate RMR are reliable tools for estimating the energy requirements of sport climbers. The study included 114 sport climbers whose RMR was measured with a Fitmate WM. Anthropometric measurements were performed with X-CONTACT 356. The resting metabolic rate was measured by indirect calorimetry and was compared with the RMR estimated by 14 predictive equations on the basis of using body weight/fat-free mass. All equations underestimated RMR in male and female climbers, except for De Lorenzo's equation in the group of women. The De Lorenzo equation demonstrated the highest correlation with RMR in both groups. The results of the Bland-Altman tests revealed an increasing measurement error with increasing metabolism for most of the predictive equations in male and female climbers. All equations had low measurement reliability according to the intraclass correlation coefficient. Compared with the indirect calorimetry measurement results, none of the studied predictive equations demonstrated high reliability. There is a need to develop a highly reliable predictive equation to estimate RMR in sport climbers.

Revised Harris-Benedict Equation: New Human Resting Metabolic Rate Equation.

This paper contains a revision of the Harris-Benedict equations through the development and validation of new equations for the estimation of resting metabolic rate (RMR) in normal, overweight, and obese adult subjects, taking into account the same anthropometric parameters. A total of 722 adult Caucasian subjects were enrolled in this analysis. After taking a detailed medical history, the study enrolled non-hospitalized subjects with medically and nutritionally controlled diseases such as diabetes mellitus, cardiovascular disease, and thyroid disease, excluding subjects with active infections and pregnant or lactating women. Measurement of somatometric characteristics and indirect calorimetry were performed. The values obtained from RMR measurement were compared with the values of the new equations and the Harris-Benedict, Mifflin-St Jeor, FAO/WHO/UNU, and Owen equations. New predictive RMR equations were developed using age, body weight, height, and sex parameters. RMR males: (9.65 × weight in kg) + (573 × height in m) - (5.08 × age in years) + 260; RMR females: (7.38 × weight in kg) + (607 × height in m) - (2.31 × age in years) + 43; RMR males: (4.38 × weight in pounds) + (14.55 × height in inches) - (5.08 × age in years) + 260; RMR females: (3.35 × weight in pounds) + (15.42 × height in inches) - (2.31 × age in years) + 43. The accuracy of the new equations was tested in the test group in both groups, in accordance with the resting metabolic rate measurements. The new equations showed more accurate results than the other equations, with the equation for men (R-squared: 0.95) showing better prediction than the equation for women (R-squared: 0.86). The new equations showed good accuracy at both group and individual levels, and better reliability compared to other equations using the same anthropometric variables as predictors of RMR. The new equations were created under modern obesogenic conditions, and do not exclude individuals with regulated (dietary or pharmacological) Westernized diseases (e.g., cardiovascular disease, diabetes, and thyroid disease).

Nutrition Therapy Promotes Overall Survival in Cachectic Cancer Patients through a New Proposed Chemical-Physical Pathway: The TiCaCONCO Trial (A Randomized Controlled Single-Blinded Trial)

Cancer threatens nutritional status, and many patients will become cachectic with a negative impact on prognosis. In the TiCaCo pilot trial, we showed a positive effect of calorie matching Nutrition Therapy on both morbidity and mortality. We attempt to validate these results in the TiCaCONCO trial. In a prospective, randomized, single-blinded, controlled trial, patients were treated with either intensive, individual biometric parameter-oriented dietary counseling (nutrition therapy or NT) for a maximum period of three months, or regular dietary counseling (control or CT), before and during conventional cancer treatment. Sixty patients were enrolled over a two-year period, with 30 receiving nutrition therapy and 30 being controls. The primary endpoint was overall survival (OS). Overall survival at 12 months in all patients was 47% (14/30 patients) in the CT group with a median OS of 45.5 weeks, and 73% (22/30 patients) in the NT group with a median OS that was undefined (i.e., cannot be calculated, as &gt;50% of patients in the NT group were still alive at the end of the study) (p = 0.0378). The survival difference still exists when only male patients are analyzed, but is not observed in female patients. Biophysical measurements were performed at 0, 3, and 12 months in all patients. In men, the differences between CT vs NT were statistically significant for body hydration (p = 0.0400), fat mass (p = 0.0480), total energy expenditure (p = 0.0320), and median overall survival at 12 months (p = 0.0390). At 3 months (end of the intervention), the differences between CT vs NT for body hydration were 73 ± 3% vs. 75 ± 5%, for fat mass 14 ± 4% vs. 19 ± 5%, and for total energy expenditure 2231 ± 637 Kcal vs. 2408 ± 369 Kcal. In women, the differences between CT vs NT were not statistically significant for body hydration (p = 1.898), fat mass (p = 0.9495), total energy expenditure (p = 0.2875) and median overall survival at 12 months (p = 0.6486). At 3 months (end of the intervention), the differences between CT vs. NT for body hydration were 74 ± 2% vs. 78 ± 5%, for fat mass 25 ± 7% vs. 29 ± 19%, and for TEE 1657 ± 297 Kcal vs. 1917 ± 120 Kcal. Nutrition Therapy, based on patient-specific biophysical parameters, including the measurement of metabolism by indirect calorimetry and body composition measurements by BIA, improves overall survival, at least in men. The mechanism would be increasing extra energy for the body, which is necessary to fight off cancer.