Changes in energy metabolism after induction therapy in patients with severe or moderate ulcerative colitis

We investigated the changes in energy expenditure during induction therapy in patients with severe or moderate ulcerative colitis. Thirteen patients (10 men, 3 women; mean age, 36.5 years) with ulcerative colitis admitted to the Shiga University Hospital were enrolled in this study. We measured the resting energy expenditure and respiratory quotients of these patients before and after induction therapy with indirect calorimetry. We analyzed the changes of nutritional status and serum inflammatory cytokine levels and also evaluated the relationship between energy metabolism and disease activity by using the Seo index and Lichtiger index. The resting energy expenditure was 26.3 ± 3.8 kcal/kg/day in the active stage and significantly decreased to 23.5 ± 2.4 kcal/kg/day after induction therapy (p<0.01). The resting energy expenditure changed in parallel with the disease activity index and C-reactive protein and inflammatory cytokine levels. The respiratory quotient significantly increased after induction therapy. Thus, moderate to severe ulcerative colitis patients had a hyper-metabolic status, and the energy metabolism of these patients significantly changed after induction therapy. Therefore, we recommend that nutritional management with 30–34 kcal/kg/day (calculated as measured resting energy expenditure × activity factor, 1.3) may be optimal for hospitalized ulcerative colitis patients.     

慢加急性肝衰竭患者的能量代谢状况

目的：探讨慢加急性肝衰竭（ ACLF）患者住院期间的动态能量代谢状况,为个体化的临床营养支持提供理论依据。方法应用美国MedGraphics CCM／D营养代谢测试系统（代谢车）测定24例好转的ACLF患者（存活组）及9例死亡的ACLF患者（死亡组）入院、住院期间、出院／死亡时的能量代谢指标及生化指标。结果存活组出院时REE／pREE与入院比较差异无统计学意义。死亡组住院期间REE／pREE与存活组比较差异有统计学意义（P＝0.008）。入院时两组呼吸商（RQ）值、碳水化合物氧化率（CHO％）均偏低,差异无统计学意义。存活组出院时RQ值及CHO％均有所上升,与入院时比较差异有统计学意义（ P＜0.05）。死亡组死亡时RQ值及CHO％均降低,RQ、CHO％与存活组出院时比较差异有统计学意义（ P＝0.006）。 Pearson相关分析显示, REE／pREE与直接胆红素、总胆汁酸、白细胞计数呈正相关,与凝血酶原活动度呈负相关。 RQ、CHO％与凝血酶原活动度、总胆固醇呈正相关,与直接胆红素、白细胞计数呈负相关。结论 ACLF患者治疗过程中趋于低代谢的状态有助于病情恢复,有利于改善患者预后;呼吸商及三大营养底物氧化比例的变化比静息能量代谢更敏感,是ACLF营养干预治疗中重要的、较好的监测指标;PTA及TC与代谢指标变化一致且灵敏,可间接体现患者的能量代谢状态。     

Discrete TrkB-expressing neurons of the dorsomedial hypothalamus regulate feeding and thermogenesis

Mutations in the TrkB neurotrophin receptor lead to profound obesity in humans, and expression of TrkB in the dorsomedial hypothalamus (DMH) is critical for maintaining energy homeostasis. However, the functional implications of TrkB-fexpressing neurons in the DMH (DMH^TrkB) on energy expenditure are unclear. Additionally, the neurocircuitry underlying the effect of DMH^TrkB neurons on energy homeostasis has not been explored. In this study, we show that activation of DMH^TrkB neurons leads to a robust increase in adaptive thermogenesis and energy expenditure without altering heart rate or blood pressure, while silencing DMH^TrkB neurons impairs thermogenesis. Furthermore, we reveal neuroanatomically and functionally distinct populations of DMH^TrkB neurons that regulate food intake or thermogenesis. Activation of DMH^TrkB neurons projecting to the raphe pallidus (RPa) stimulates thermogenesis and increased energy expenditure, whereas DMH^TrkB neurons that send collaterals to the paraventricular hypothalamus (PVH) and preoptic area (POA) inhibit feeding. Together, our findings provide evidence that DMH^TrkB neuronal activity plays an important role in regulating energy expenditure and delineate distinct neurocircuits that underly the separate effects of DMH^TrkB neuronal activity on food intake and thermogenesis.

Impairments in energy homeostasis resulting from the compound effects of overeating and sedentary lifestyles have led to a profound increase in the rate of obesity around the world (1). Therapeutic strategies aimed at combating obesity by increasing energy expenditure or decreasing appetite have commonly failed due to counterregulatory mechanisms (2) and adverse side effects on cardiovascular physiology (3–5). To achieve safe and sustained weight loss, it will be essential to understand the mechanisms that govern and coordinate discrete physiological processes that contribute to energy homeostasis.Adaptive thermogenesis is the process by which energy is converted into heat and occurs primarily in brown adipose tissue (BAT) in response to environmental cues (6). BAT has a particularly high capacity for dissipating energy from fat and thus represents an important component of energy homeostasis. The dorsomedial hypothalamus (DMH) in the brain is centrally positioned in an established thermoregulatory neurocircuit, receiving inputs from the preoptic area (POA) (7–9) and sending excitatory projections to preautonomic neurons in the raphe pallidus (RPa) (10–13) that promote sympathetic activity in BAT, leading to increased thermogenesis. Direct chemical stimulation of the DMH (14) or activation of select populations of thermogenic DMH neurons (9, 11, 12, 15) leads to increased body temperature and energy expenditure but also significantly increases heart rate and blood pressure (12, 13, 15, 16). An inability to target increased sympathetic tone specifically in BAT without affecting other target tissues has greatly hampered strategies to treat obesity by targeting thermogenesis (4, 5).In addition to its influence on energy expenditure, the DMH also represents an important brain region in the regulation of feeding (17–19). Lesioning studies support an orexigenic role for the DMH (17), which can promote food intake through inhibitory projections to either the paraventricular hypothalamus (PVH) (18) or the arcuate nucleus (ARC) (20). Despite these early findings, evidence has also emerged that demonstrates the importance of anorexigenic populations of DMH neurons (19, 21, 22). We previously established that the activity of DMH neurons expressing the neurotrophin receptor TrkB (DMH^TrkB) is important for regulating feeding, showing that activation of DMH^TrkB neurons suppresses feeding and that deletion of the TrkB-encoding Ntrk2 gene in the DMH results in hyperphagia and obesity (21). Furthermore, humans with mutations in the TrkB-encoding NTRK2 gene exhibit severe obesity and impaired thermoregulation (23). However, it is unclear whether activation of DMH^TrkB neurons has a direct influence on adaptive thermogenesis. Additionally, the neurocircuitry through which DMH^TrkB neurons govern feeding or energy expenditure is unknown.Here, we demonstrate that DMH^TrkB neuronal activity potently promotes energy expenditure by elevating thermogenesis and physical activity with a notable lack of influence on heart rate and blood pressure. We further reveal that DMH^TrkB neurons send diverging projections to the RPa or the POA and PVH to differentially regulate energy expenditure and food intake, respectively.     

Energy utilization associated with regular activity breaks and continuous physical activity: A randomized crossover trial

Aims

To quantify and compare energy utilization associated with prolonged sitting alone, or interrupted with regular activity breaks and/or an additional bout of continuous physical activity.

Self‐report use‐of‐time tools for the assessment of physical activity and sedentary behaviour in young people: systematic review

Regular physical activity and limiting extended periods of sitting are two behaviours critical for the prevention of obesity in young people. The purpose of the systematic review was to synthesize the psychometric evidence for self‐report use‐of‐time tools that assess these behaviours. Articles were retrieved that reported reliability and/or validity for use‐of‐time tools in participants aged 18 years or under. Outcome variables were physical activity, sedentary behaviour and energy expenditure. Study quality was appraised, and the results summarized narratively. Sixteen studies and six different tools were identified. The tools were the Previous Day Physical Activity Recall, the Three‐Day Physical Activity Recall, the Physical Activity Interview, the Computerized Activity Recall, the Activitygram, and the Multimedia Activity Recall for Children and Adolescents. Overall, tools indicated moderate validity compared with objective and criterion comparison methods. Generally, validity correlation coefficients were in the range of 0.30–0.40. Correlation coefficients for test–retest reliability ranged widely from 0.24 to 0.98. Conclusion: Use‐of‐time tools have indicated moderate reliability and validity for the assessment of physical activity and energy expenditure. Future research should focus on using criterion methods and on validating specifically for sedentary behaviour outcomes. Implementation of these tools for population surveillance should be considered.     

Evaluation of activity monitors in manual wheelchair users with paraplegia

Abstract

Objective: The aim of this study was to evaluate the performance of SenseWear^® (SW) and RT3 activity monitors (AMs) in estimating energy expenditure (EE) in manual wheelchair users (MWUs) with paraplegia for a variety of physical activities.

Methods: Twenty-four subjects completed four activities including resting, wheelchair propulsion, arm-ergometry exercise, and deskwork. The criterion EE was measured by a K4b2 portable metabolic cart. The EE estimated by the SW and RT3 were compared with the criterion EE by the absolute differences and absolute percentage errors. Intraclass correlations and the Bland and Altman plots were also used to assess the agreements between the two AMs and the metabolic cart. Correlations between the criterion EE and the estimated EE and sensors data from the AMs were evaluated.

Results: The EE estimation errors for the AMs varied from 24.4 to 125.8% for the SW and from 22.0 to 52.8% for the RT3. The intraclass correlation coefficients (ICCs) between the criterion EE and the EE estimated by the two AMs for each activity and all activities as a whole were considered poor with all the ICCs smaller than 0.75. Except for deskwork, the EE from the SW was more correlated to the criterion EE than the EE from the RT3.

Conclusion: The results indicate that neither of the AMs is an appropriate tool for quantifying physical activity in MWUs with paraplegia. However, the accuracy of EE estimation could be potentially improved by building new regression models based on wheelchair-related activities.