BACKGROUND: Evaluating energy expenditure is important for establishing optimal goals for nutrition treatment. However, indirect calorimetry, the reference standard for measuring energy expenditure, is difficult to apply widely in clinical practice.
OBJECTIVE: To test the consistency of bioelectrical impedance analysis (BIA) relative to indirect calorimetry for evaluating energy expenditure in critically ill patients.
METHODS: A cross-sectional study of 140 critically ill adult patients was conducted. Within 24 hours of a patient being transferred to the intensive care unit, trained researchers assessed the patient\'s energy expenditure by use of BIA and indirect calorimetry simultaneously. Consistency of the 2 measurements was detected by intraclass correlation coefficients with a 2-way random-effects model. Factors affecting consistency were analyzed.
RESULTS: Median energy expenditure measured by indirect calorimetry was 1430.0 kcal/d (IQR, 1190.5-1650.8 kcal/d). Median energy expenditure measured by BIA was 1407.0 kcal/d (IQR, 1248.5-1563.5 kcal/d). The correlation coefficient between indirect calorimetry and BIA was 0.813 (95% CI, 0.748-0.862; P < .001). The consistency of the 2 measurements was lower in patients with comorbidities than in those without (P = .004).
CONCLUSIONS: Results of BIA were highly consistent with indirect calorimetry assessments of energy expenditure in critically ill patients. Few factors except comorbidity affect the accuracy of BIA when assessing energy expenditure. Therefore, as a low-cost, easy-to-use, and noninvasive method, BIA is a valuable clinical tool for assessing energy expenditure in critically ill patients.

Blood lactate concentration during exercise is a reliable indicator of energy metabolism and endurance performance. Lactate is also present in sweat, and sweating plays an important role in thermoregulation, especially in hot conditions. Recently, wearable sensors have enabled the real-time and noninvasive measurement of sweat lactate concentration, potentially serving as an alternative indicator of blood lactate response. However, the evidence regarding the relationship between sweat and blood lactate responses during incremental exercise in hot conditions is lacking. In a randomized cross-over design, six highly trained male runners completed two incremental treadmill tests under normal (20°C/50%RH) or hot (30°C/50%RH) conditions. The tests include 3-min running stages and 1-min recovery, starting at 12 km/h and increasing by 1 km/h at each stage. Blood and sweat lactate concentrations were measured at each stage to determine blood and sweat lactate thresholds (LT). Blood lactate concentrations were higher under hot conditions (p < 0.01), but there was no difference in the response pattern or velocity at blood LT between conditions. Significant early increase (p < 0.01) in sweat lactate and low velocity at sweat LT (p < 0.05) were observed under hot conditions. A significant correlation between blood and sweat lactate concentrations was found under normal conditions (p < 0.001) but not under hot conditions, and no significant correlations were observed between the velocity at blood and sweat LT. In conclusion, sweat lactate concentration does not consistently reflect blood lactate concentration during incremental exercise.

Acute myeloid leukemia (AML), one of the most common types of leukemia, is characterized by its high malignancy and rapid progression with a 5-year survival rate of less than 30%. The incidence and mortality rates of AML are increasing with age. Over the past few decades, progress in AML treatment has been relatively slow. While traditional approaches such as chemotherapy and hematopoietic stem cell transplantation have significant limitations including treatment toxicity and chemotherapy resistance, recent advancements in the in-depth study of AML mechanisms have made targeted therapy a new option for AML treatment. Metabolic reprogramming is one of the key features of cancer, and mitochondrial dysfunction has been widely studied in various cancers. Mitochondrial dysfunction is prevalent in AML cells and closely associated with the development of AML. The AML cells exhibit significant differences from normal hematopoietic cells in energy metabolism, autophagy, apoptosis, and other aspects. Given that mitochondria are at the core of cellular energy metabolism, inhibiting pathways related to mitochondrial function holds significant potential for AML treatment. This review aims to explore recent advances on the role of mitochondrial dysfunction in AML cell survival, potential therapeutic targets in mitochondria, and related targeted drugs, aiming to provide ideas for the development of targeted therapies for AML.

New Zealand blackcurrant (NZBC) is known to alter exercise-induced physiological and metabolic responses with chronic (i.e., 7 days) dosing. We examined the effects of acute intake of New Zealand blackcurrant (NZBC) extract on 4 h indoor cycling-induced physiological and metabolic responses in a male amateur Ironman athlete (age: 49 years; BMI: 24.3 kg·m-2; V˙O2max: 58.6 mL·kg-1·min-1; maximal aerobic power: 400 W; history: 14 Ironman events in 16 years) three weeks before competition. Indirect calorimetry was used and heart rate was recorded at 30 min intervals during 4 h indoor (~22.4 °C, relative humidity: ~55%) constant power (165 W) cycling on a Trek Bontrager connected to a Kickr smart trainer. Blood lactate and rating of perceived exertion (RPE) were taken at 60 min intervals. Study was a single-blind placebo-controlled study with capsules (4 × 105 mg anthocyanins) taken 2 h before starting the 4 h of cycling. Water was allowed ad libitum with personalised consumption of gels [a total of eight with three with caffeine (100 mg)], two bananas and 8 × electrolyte capsules (each 250 mg sodium and 125 mg potassium) at personalised time-points. With NZBC extract (CurraNZ), during 4 h of cycling (mean of 8 measurements), minute ventilation was 8% lower than placebo. In addition, there was no difference for oxygen uptake, with carbon dioxide production found to be 4% lower with NZBC extract. With the NZBC extract, the ventilatory equivalents were lower for oxygen and carbon dioxide by 5.5% and 3.7%; heart rate was lower by 10 beats·min-1; lactate was 40% different with lower lactate at 2, 3 and 4 h; RPE was lower at 2, 3 and 4 h; and carbohydrate oxidation was 11% lower. With NZBC extract, there was a trend for fat oxidation to be higher by 13% (p = 0.096), with the respiratory exchange ratio being lower by 0.02 units. Acute intake of New Zealand blackcurrant extract (420 mg anthocyanins) provided beneficial physiological and metabolic responses during 4 h of indoor constant power cycling in a male amateur Ironman athlete 3 weeks before a competition. Future work is required to address whether acute and chronic dosing strategies with New Zealand blackcurrant provide a nutritional ergogenic effect for Ironman athletes to enhance swimming, cycling and running performance.

While an intensity-dependent post-exercise decrease in energy intake (EI) has been described in adolescents with obesity, studies invariably used ad libitum meals, limiting then any conclusions regarding the effect of exercise on post-meal appetitive responses that can be also impacted by the ad libitum nature of the meal. This study analyses appetite and food-reward related responses to a fixed meal after an acute exercise, also exploring the associations between substrate use during exercise and overall daily EI in adolescents with obesity. Thirteen adolescents with obesity (12-16 years, 5 males) randomly complete 2 experimental sessions: (i) a control condition (CON); (ii) a 30-min moderate intensity (65% VO2peak) cycling condition (EX). Energy expenditure and substrate oxidation were measured during both 30 min of rest (CON) or exercise (EX). Ad libitum EI, macronutrient intake and relative EI were assessed at dinner, subjective appetite sensations taken at regular intervals and food reward measured before and after lunch as well as before dinner. Energy and macronutrient intake did not differ between conditions, as well as appetite feelings. A time effect (p = 0.012) was observed between pre and post meal for choice fat bias in both conditions but was only significant within the CON condition (p = 0.004). CHO oxidation during exercise was found correlated with both EI (r = 0.586, p = 0.045), pre-lunch hunger (r = 0.624, p = 0.030), daily AUC for hunger and DTE (r = 0.788, p = 0.002 and r = 0.695; p = 0.012 respectively). This exploratory study highlights that acute exercise might not affect subsequent appetite responses when using a fixed test meal in adolescents with obesity.

We conducted a small, open-label, pilot study of daratumumab to explore target engagement, safety, and potential efficacy in patients with mild to moderate Alzheimer\'s disease. Daratumumab SC 1800 mg was given subcutaneously weekly for 8 weeks, then every 2 weeks for 16 weeks. Flow cytometry to measure the CD38+ proportion of CD8 + CD4- T cells and cognitive assessments were performed at baseline, day 176, and day 246. Daratumumab significantly reduced CD38 + CD8 + CD4- T cells after 24 weeks and this effect persisted 11 weeks thereafter. There was no hematological toxicity or unexpected adverse events. Responder analysis showed no improvement on cognitive outcome measures.

OBJECTIVE: In recent times, the complexity of food styles and meal content has increased, leading to significant variations in macronutrient composition between meals. This phenomenon has coincided with a rise in obesity rates. We aimed to determine whether a large variation in macronutrient composition between meals results in reduced fat oxidation.
METHODS: A cross-over study was conducted with 13 healthy young men, using whole-body indirect calorimetry to test 24-h energy metabolic responses under three conditions: regular meals (R), high-carbohydrate breakfast (CB), or high-fat breakfast (FB), each with different macronutrient contents. The R condition included three meals daily with the same macronutrient composition. The CB condition included a high-carbohydrate meal at breakfast, high-fat meal at lunch, and high-carbohydrate meal at dinner. The FB condition included a high-fat meal at breakfast, high-carbohydrate meal at lunch, and high-carbohydrate meal at dinner. The daily macronutrient compositions were similar across the three conditions, except that CB and FB had larger variations in carbohydrate-fat balance between meals than R. The participants were tested in random order. During the dietary intervention, we compared 24-h whole-body metabolic parameters, including substrate oxidation (e.g., 24 h respiratory quotient [RQ]).
RESULTS: No significant differences were observed in the measures of energy expenditure among the three conditions. However, after adjusting for the sleeping RQ on a preceding day, the estimated 24hRQ was lower under the FB condition (0.845) than under the R (0.854, P = 0.0077 vs. FB) and CB conditions (0.853, P = 0.016 vs. FB). No difference was observed in the magnitude of the 5-h RQ change from lunch to dinner under the CB condition and in the magnitude of change from breakfast to lunch under the FB condition.
CONCLUSIONS: A large variation in the carbohydrate-fat balance between meals does not decrease daily fat oxidation. An FB may increase daily fat oxidation compared to a CB when the daily food quotient is constant, but this increase may not be owing to the upregulation of fat burning on a daily basis.

OBJECTIVE: Accurately estimating resting energy requirements is crucial for optimizing energy intake, particularly in the context of patients with varying energy needs, such as individuals with cancer. We sought to evaluate the agreement between resting energy expenditure (REE) predicted by 40 equations and that measured by reference methods in women undergoing active breast cancer treatment stage (I-IV) and post-completion (i.e., survivors).
METHODS: Data from 4 studies were combined. REE values estimated from 40 predictive equations identified by a systematic search were compared with REE assessed by indirect calorimetry (IC) using a metabolic cart (MC-REE N = 46) or a whole-room indirect calorimeter (WRIC-REE N = 44). Agreement between methods was evaluated using Bland-Altman and Lin\'s concordance coefficient correlation (Lin\'s CCC).
RESULTS: Ninety participants (24 % survivors, 61.1% had early-stage breast cancer I or II, mean age: 56.8 ± 11 years; body mass index: 28.7 ± 6.4 kg/m2) were included in this analysis. Mean MC-REE and WRIC-REE values were 1389 ± 199 kcal/day and 1506 ± 247 kcal/day, respectively. Limits of agreement were wide for all equations compared to both MC and WRIC (∼300 kcal for both methods), including the most commonly used ones, such as Harris-Benedict and Mifflin ST. Jeor equations; none had a bias within ±10% of measured REE, and all had low agreement per Lin\'s CCC analysis (<0.90). The Korth equation exhibited the best performance against WRIC and the Lvingston-Kohlstadt equation against MC. Similar patterns of bias were observed between survivors and patients and between patients with stages I-III versus IV cancer.
CONCLUSIONS: Most equations failed to accurately predict REE at the group level, and none were effective at the individual level. This inaccuracy has significant implications for women with or surviving breast cancer, who may experience weight gain, maintenance, or loss due to inaccurate energy needs estimations. Therefore, our research underscores the need for further efforts to improve REE estimation.

BACKGROUND: The study investigates the correlation between muscle mass and physical activity level measured objectively and subjectively in older adults who fall or are at high risk of falling.
METHODS: FITNESS (Fall Interest to Target Newly Sarcopenic Society) is a multi-center (French university hospitals of Angers, Lille, Limoges and Orléans), cross-sectional, observational study of routine care within a French multidisciplinary hospital consultation. Inclusion criteria were ≥ 75 years old, living at home and consulting for fall or gait disorder. A standardized geriatric assessment, muscle mass evaluation by impedancemetry, physical activity by continuous actimetry (5 days) and Incidental and Planned Exercise Questionnaire (IPEQ) were performed at patient inclusion.
RESULTS: 170 people aged 75 and over were included in the FITNESS study (mean age 82.9 ±4.7 years, women 72.9%). Muscle mass (whole body and lower limbs) correlated with active energy expenditure (AEE, ρ whole body = 0.32, p-value < 0.001; ρ lower limbs = 0.25, p-value = 0.003), but not with number of daily steps, nor with IPEQ score. Multivariate analysis of whole-body muscle mass showed a positive and significant association with AEE and albumin levels and for lower limb muscle mass, a positive association with AEE and Charlson.
CONCLUSIONS: This study suggests that in the particular population of older adults who fall and/or are at high risk of falling, loss of muscle mass correlates with reduced physical activity. So subjects who fall or at high risk of falling constitute a special group for whom the fight against sedentary lifestyles and the maintenance of physical activity should be a dual priority.

BACKGROUND: Slower gait speed may be driven by greater energy deficits and fatigability among older adults. We examined associations of walking energetics and perceived physical fatigability with gait speed among slower and faster walkers. Additionally, we used statistical mediation to examine the role of fatigability in the associations of walking energetics and gait speed using the Study of Muscle, Mobility and Aging (SOMMA).
METHODS: Perceived physical fatigability was assessed using the Pittsburgh Fatigability Scale (PFS) Physical score (range 0-50, higher = greater). A 3-phase cardiopulmonary exercise treadmill test collected peak oxygen consumption (VO2peak, mL/kg/min), energetic cost of walking (ECW, mL/kg/m), and cost-capacity ratio (VO2/VO2peak*100, %). Slower (<1.01 m/s) versus faster (≥1.01 m/s) walkers were classified using median 4-m gait speed. Linear regressions and statistical mediation analyses were conducted.
RESULTS: Slower walkers had lower VO2peak, higher ECW at preferred walking speed (PWS), and greater PFS Physical score compared to faster walkers (all p < .05; N = 849). One standard deviation (1-SD) higher VO2peak was associated with 0.1 m/s faster gait speed, while 1-SD higher ECW PWS, cost-capacity ratio at PWS and slow walking speed (SWS), and PFS Physical score were associated with 0.02-0.23 m/s slower gait speed. PFS Physical score was a significant statistical mediator in the associations between VO2peak (15.2%), SWS cost-capacity ratio (15.9%), and ECW PWS (10.7%) with gait speed and was stronger among slower walkers.
CONCLUSIONS: Slower walkers may be more influenced by perceptions of fatigue in addition to walking energetics. Our work highlights the importance of targeting both energetics and perceived fatigability to prevent mobility decline.