Energy Expenditure In Cancer Research Articles

Circadian Rhythm in Energy Expenditure in Cancer In-and Out-Patients: A Comparative Study

Unlike normal humans, an alteration in circadian pattern in energy expenditure (EE) has been observed in cancer patients. In the current cross sectional study we examined rhythm characteristics of EE in cancer in- (n = 30) and out-patients (n = 26), and healthy controls (n = 30). EE was assessed non-invasively using an electronic device - the Actical, programmed with data sampling epoch of 60 seconds. All patients and control subjects wore instrument on their non-dominant hand for 3- 4 consecutive days. Cosinor rhythmometry was used to determine the rhythm characteristics, such as 24-h average/Mesor, amplitude, and peak/acrophase of EE. Circadian and rhythm quotients were derived from the rhythm characteristics. Two- way ANOVA was employed to determine the effects of factors, ‘group’ and ‘gender’ on rhythm characteristics. A significant circadian rhythm in EE was validated in all groups. However, rhythm detection ratio, at 12 h period, was found to be low in both cancer in- and out-patients as compared to controls. Factor ‘group’ produced significant effect on 24 -h average, amplitude, acrophase, rhythm quotient and circadian quotient of EE rhythm. However, effects of factor ‘gender’ and interaction of both factors was significant on circadian quotient only. At the group level, rhythm characteristics, namely 24-h average, amplitude, and circadian quotient of three groups varied from each other significantly in the following order: in - patient < out-patient < control. In conclusion, EE rhythm deteriorated in both in- and out-patients as compared to control subjects, although the deterioration was more pronounced in cancer in-patients. We suggest that further extensive investigation involving larger sample should be carried out to validate the above findings.

Inorganic polyphosphate as an energy source in tumorigenesis.

Cancer cells have high demands for energy to maintain their exceedingly proliferative growth. However, the mechanism of energy expenditure in cancer is not well understood. We hypothesize that cancer cells might utilize energy-rich inorganic polyphosphate (polyP), as energetic reserve. PolyP is comprised of orthophosphates linked by phosphoanhydride bonds, as in ATP. Here, we show that polyP is highly abundant in several types of cancer cells, including brain tumor-initiating cells (BTICs), i.e., stem-like cells derived from a mouse brain tumor model that we have previously described. The polymer is avidly consumed during starvation of the BTICs. Depletion of ATP by inhibiting glycolysis and mitochondrial ATP-synthase (OXPHOS) further decreases the levels of polyP and alters morphology of the cells. Moreover, enzymatic hydrolysis of the polymer impairs the viability of cancer cells and significantly deprives ATP stores. These results suggest that polyP might be utilized as a source of phosphate energy in cancer. While the role of polyP as an energy source is established for bacteria, this finding is the first demonstration that polyP may play a similar role in the metabolism of cancer cells.

MON-P099: Predicting Energy Expenditure in Cancer: Impact of Body Composition, Tumour Stage and Inflammation

MON-P099: Predicting Energy Expenditure in Cancer: Impact of Body Composition, Tumour Stage and Inflammation

Key determinants of energy expenditure in cancer and implications for clinical practice.

Great discrepancies exist in the reported prevalence of altered energy metabolism (hypo- or hypermetabolism) in cancer patients, which is likely due to the vast array of phenomena that can affect energy expenditure in these patients. The purpose of this review was to critically evaluate key determinants of energy expenditure in cancer and the relevance for clinical practice. Resting energy expenditure (REE) is the largest and most commonly measured component of total energy expenditure. In addition to the energetic demand of the tumor itself, REE may be increased due to changes in inflammation, body composition and brown adipose tissue activation. Energy expenditure from physical activity is often lower in cancer compared with healthy populations, and there is evidence to suggest that the thermic effect of food might also be blunted and affected by cancer therapy. Although accurate assessment of energy metabolism is a cornerstone of adequate nutritional therapy, prediction methods often do not capture the true energy expenditure of most cancer patients. In fact, limits of agreement of prediction equations may range from 40% below to 30% above measured REE. Such variability highlights the need for a more comprehensive understanding of energy expenditure in cancer and the value of accurately assessing the energy needs of these patients.

How Elevated is Resting Energy Expenditure in Cancer: A Meta-Analysis

How Elevated is Resting Energy Expenditure in Cancer: A Meta-Analysis

Energy Expenditure in Cancer

Energy Expenditure in Cancer

Energy expenditure in cancer

Energy expenditure as a factor in both the pathogenesis of cancer cachexia and in the clinical course of a malignancy has received relatively little attention in the oncology nursing literature. Nursing interventions that are done to influence nutritional status and day-to-day functional abilities of cancer patients may be compromised by alterations in energy requirements and availability of nutrients. Energy expenditure as one clinical manifestation of cancer and current measurement techniques for assessing energy expenditure are described. By becoming more familiar with the current state of knowledge of aberrations in energy expenditure that accompany cancer, nurses may be able to anticipate more accurately patterns of patient debility and to incorporate more refined strategies for assisting patients and families to cope with changes.