scholarly journals Part 1 Substrate metabolism in the metabolic response to injury

2000 ◽  
Vol 59 (3) ◽  
pp. 447-449 ◽  
Author(s):  
J. A. Romijn

In healthy subjects the metabolic response to starvation invokes regulatory mechanisms aimed at conservation of protein mass. This response is characterized by a decrease in energy expenditure and a progressive decrease in urinary N excretion. Many non-endocrine diseases induce anorexia and a decrease in food intake. However, in contrast to the metabolic reaction to starvation in healthy subjects, anorectic patients with serious diseases have increased energy expenditure and protein catabolism, associated with profound neuroendocrine alterations. These neuroendocrine changes are induced by two mechanisms. First, afferent nerves inform the central nervous system of tissue injury which results in neuroendocrine activation. Second, tissue injury stimulates the production of inflammatory mediators, which in turn results in neuroendocrine and metabolic effects. Although these metabolic changes enable the organism to survive short-lasting diseases by using endogenous substrates, in protracted serious diseases these changes will result in loss of functioning protein mass and may endanger survival. Moreover, tissue injury alters the metabolic responses to nutrition, reflected in the persistence of catabolism as long as serious tissue injury remains.

2018 ◽  
Vol 19 (9) ◽  
pp. 2569 ◽  
Author(s):  
María García ◽  
Patricia Pazos ◽  
Luis Lima ◽  
Carlos Diéguez

Obesity rates and the burden of metabolic associated diseases are escalating worldwide Energy burning brown and inducible beige adipocytes in human adipose tissues (ATs) have attracted considerable attention due to their therapeutic potential to counteract the deleterious metabolic effects of nutritional overload and overweight. Recent research has highlighted the relevance of resident and recruited ATs immune cell populations and their signalling mediators, cytokines, as modulators of the thermogenic activity of brown and beige ATs. In this review, we first provide an overview of the developmental, cellular and functional heterogeneity of the AT organ, as well as reported molecular switches of its heat-producing machinery. We also discuss the key contribution of various interleukins signalling pathways to energy and metabolic homeostasis and their roles in the biogenesis and function of brown and beige adipocytes. Besides local actions, attention is also drawn to their influence in the central nervous system (CNS) networks governing energy expenditure.


2011 ◽  
Vol 70 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Federico Bozzetti

The metabolic response to surgical trauma is mainly characterised by an increase in BMR, a negative N balance, increased gluconeogenesis and increased synthesis of acute-phase proteins. These reactions aim at ensuring the availability of endogenous substrates for healing wounds while the synthesis of acute-phase proteins enhances the scavenging process and helps repair. However, if this process is excessive or continues for too long, it leads to a progressive depletion of body compartment with a consequent adverse outcome. Obviously, the severity of such depletion is magnified if the patient is starving or is already malnourished and the consumption of lean body mass is not compensated by an exogenous supply of nutrients. The nutritional control of this metabolic reaction represents the traditional rationale for nutritional support of surgical patients. Subsequent data have shown that the negative effects of starvation are not simply due to the starvation per se but due to the starving gut, and peri-operative enteral nutrition has proven successful in blunting the metabolic response after injury and improving protein kinetics, net balance and amino acid flux across peripheral tissue and consequently in decreasing the complications. Finally, further clinical research has shown that many post-operative infections may result from immune suppression and that such state might be reversed to some degree by modulation of the immune response through specialised nutritional support in surgical patients, regardless of their nutritional status. This paper will focus on the updated evidence-based research on peri-operative nutrition (parenteral, enteral and immune-enhancing) in patients undergoing major surgery.


2000 ◽  
Vol 98 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Matthew D. BARBER ◽  
Donald C. MCMILLAN ◽  
Tom PRESTON ◽  
James A. ROSS ◽  
Kenneth C. H. FEARON

Weight-losing patients with advanced cancer often fail to gain weight with conventional nutritional support. This suboptimal response might be explained, in part, by an increased metabolic response to feeding. It has been suggested that eicosapentaenoic acid (EPA) can modify beneficially the metabolic response to cancer. The aim of the present study was to examine the metabolic response to feeding in cancer and the effects of an EPA-enriched oral food supplement on this response. A total of 16 weight-losing, non-diabetic patients with unresectable pancreatic adenocarcinoma and six healthy, weight-stable controls were studied by indirect calorimetry in the fasting and fed states. Body composition was estimated by bioimpedence analysis. Cancer patients were then given a fish-oil-enriched nutritional supplement providing 2 g of EPA and 2550 kJ daily, and underwent repeat metabolic study after 3 weeks of such supplementation. At baseline, resting energy expenditure whether expressed per kg body weight, lean body mass or body cell mass was significantly greater in the cancer patients compared with controls. Fat oxidation was significantly higher in the fasting state in cancer patients [median 1.26 g·kg-1·min-1 (interquartile range 0.95–1.38)] than in controls [0.76 g·kg-1·min-1 (0.62–0.92); P < 0.05]. Over the 4 h feeding period, changes in insulin and glucose concentrations in cancer patients suggested relative glucose intolerance. In response to oral meal feeding, the percentage change in the area under the curve of energy expenditure was significantly lower in the cancer patients [median 7.9% (interquartile range 3.4–9.0)] than in controls [12.6% (9.9–15.1); P < 0.01]. After 3 weeks of the EPA-enriched supplement, the body weight of the cancer patients had increased and the energy expenditure in response to feeding had risen significantly [9.6% (6.3–12.4)], such that it was no different from baseline healthy control values. Similarly, fasting fat oxidation fell to 1.02 g·kg-1·min-1 (0.8–1.18), again no longer significantly different from baseline healthy control values. While weight-losing patients with advanced pancreatic cancer have an increased resting energy expenditure and increased fat oxidation, the energy cost of feeding is, in fact, reduced. Provision of a fish-oil-enriched nutritional supplement results in some normalization of the metabolic response in both the fasted and fed states, in association with an improvement in nutritional status.


1974 ◽  
Vol 52 (3) ◽  
pp. 575-582 ◽  
Author(s):  
Jeremy S. D. Winter

The effects of exhausting bicycle exercise at close to maximal work capacity upon circulating levels of hormones and energy substrates in 4 fasting growth-hormone-deficient and 15 fasting healthy subjects (aged 13–18 years) have been studied. As expected, only the healthy subjects showed a rise in plasma growth hormone (GH) levels. In both groups plasma insulin tended to fall, but the decline was more prolonged in the GH-de-ficient group. Plasma Cortisol levels rose in both groups with the exception of one adrenocorticotropin (ACTH)-deficient subject. Blood sugar levels were well-maintained in all but this ACTH-deficient subject, whereas both groups showed marked lactate accumulation. Both groups demonstrated an initial fall and then a secondary rise in serum free fatty acid concentrations; however, fatty acid levels were lower in the GH-deficient group and there was no post-exercise overshoot, suggesting a possible reduction in the effectiveness of lipid mobilization.


1992 ◽  
Vol 55 (4) ◽  
pp. 851-856 ◽  
Author(s):  
J E Swanson ◽  
D C Laine ◽  
W Thomas ◽  
J P Bantle

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.


2019 ◽  
Author(s):  
Vanessa Teckentrup ◽  
Sandra Neubert ◽  
João C. P. Santiago ◽  
Manfred Hallschmid ◽  
Martin Walter ◽  
...  

AbstractMetabolic feedback between the gut and the brain relayed via the vagus nerve contributes to energy homeostasis. We investigated in healthy adults whether non-invasive stimulation of vagal afferents impacts energy homeostasis via efferent effects on metabolism or digestion. In a randomized crossover design, we applied transcutaneous auricular vagus nerve stimulation (taVNS) while recording efferent metabolic effects using simultaneous electrogastrography (EGG) and indirect calorimetry. We found that taVNS reduced gastric myoelectric frequency (p =.008), but did not alter resting energy expenditure. We conclude that stimulating vagal afferents induces gastric slowing via vagal efferents without acutely affecting net energy expenditure at rest. Collectively, this highlights the potential of taVNS to modulate digestion by activating the dorsal vagal complex. Thus, taVNS-induced changes in gastric frequency are an important peripheral marker of brain stimulation effects.


2021 ◽  
Vol 12 ◽  
Author(s):  
Christopher A. M. Bannon ◽  
Daniel Border ◽  
Petra Hanson ◽  
John Hattersley ◽  
Martin O. Weickert ◽  
...  

PurposeTo compare metabolic effects of modified release hydrocortisone (MR-HC) with standard hydrocortisone (HC) therapies in adults with Adrenal Insufficiency (AI).MethodsAdult patients (n = 12) with AI, established on HC therapy, were recruited from Endocrinology clinics at University Hospitals Coventry and Warwickshire (UHCW), UK. Baseline (HC) metabolic assessments included fasting serum HbA1C, lipid and thyroid profiles, accurate measures of body composition (BodPod), and 24-h continuous measures of energy expenditure including Sleeping Metabolic Rate (SMR) using indirect calorimetry within the Human Metabolism Research Unit, UHCW. All participants then switched HC to MR-HC with repeat (MR-HC) metabolic assessments at 3 months. Paired-sample t-tests were used for data comparisons between HC and MR-HC assessments: P-value &lt;0.05 was considered significant.ResultsFollowing exclusion of 2 participants, analyses were based on 10 participants. Compared with baseline HC data, following 3 months of MR-HC therapy mean fat mass reduced significantly by −3.2 kg (95% CI: −6.0 to −0.4). Mean (SD) baseline HC fat mass vs repeat MR-HC fat mass: 31.9 kg (15.2) vs 28.7 kg (12.8) respectively, P = 0.03. Mean SMR increased significantly by +77 kcal/24 h (95% CI: 10–146). Mean (SD) baseline HC SMR vs repeat MR-HC SMR: 1,517 kcal/24 h (301) vs 1,594 kcal/24 h (344) respectively, P = 0.03. Mean body fat percentage reduced significantly by −3.4% (95% CI: −6.5 to −0.2). Other measures of body composition, energy expenditure, and biochemical analytes were equivalent between HC and MR-HC assessments.ConclusionsIn adults with AI, switching from standard HC to MR-HC associates with early metabolic benefits of reduced fat mass and increased SMR.


1995 ◽  
Vol 268 (5) ◽  
pp. E813-E819 ◽  
Author(s):  
J. M. Stouthard ◽  
J. A. Romijn ◽  
T. Van der Poll ◽  
E. Endert ◽  
S. Klein ◽  
...  

Interleukin-6 (IL-6) is one of the major circulating cytokines in catabolic states. To investigate its endocrinologic and metabolic actions in vivo, we studied eight patients with metastatic renal cell cancer two times, once during infusion of saline (control) and once during a 4-h infusion of 150 micrograms recombinant human IL-6 (rhIL-6). Rates of appearance (Ra) of glucose and free fatty acids (FFA) in plasma were measured by using the isotope dilution method. Energy expenditure and substrate oxidation were determined by indirect calorimetry. rhIL-6 induced increases in plasma norepinephrine (+261 +/- 97%, P < 0.001), cortisol (+210 +/- 48%, P < 0.001), and glucagon (+70 +/- 18%, P < 0.001), in resting energy expenditure (+25 +/- 2%, P < 0.001 vs. control), and in plasma FFA concentration (+60 +/- 30%, P < 0.001), FFA Ra (+105 +/- 18%, P < 0.001), and fat oxidation (+38 +/- 16%, P < 0.001). Glucose Ra increased by 20 +/- 5% (P < 0.01) during rhIL-6 infusion with a concomitant increase in the metabolic clearance rate of glucose. In conclusion, our data demonstrate that rhIL-6 induces many of the endocrinologic and metabolic changes found in catabolic states and thus may mediate some of the metabolic effects previously ascribed to other cytokines.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Amy C Burke ◽  
Dawn E Telford ◽  
Brian G Sutherland ◽  
Jane Y Edwards ◽  
Murray W Huff

Previously, we have shown that intervention by the addition of the citrus flavonoid naringenin to a chow diet enhances the reversal of diet-induced metabolic dysregulation, obesity, and atherosclerosis. However, the metabolic effects of naringenin in the absence of obesity and metabolic dysregulation are unknown. In the present study, we assessed the effect of naringenin supplementation to a chow diet on plasma lipids, adiposity, respiratory exchange ratio (RER), ambulatory activity and tissue lipolysis. For 8 weeks, Ldlr -/- mice were fed an isoflavone-free chow diet supplemented with or without 3% naringenin. Over 8 weeks, there was no difference in caloric intake between the two groups. Naringenin supplementation reduced plasma VLDL-cholesterol (C) (-46%; P <0.05), VLDL-triglycerides (-43%; P <0.05), and LDL-C (-27%; P <0.05) compared to mice consuming chow alone. Chow-fed mice maintained body weight, whereas mice fed chow with naringenin were ~1.4 g lighter ( P <0.05) with significantly reduced adiposity (-48%; P <0.05). Histological analysis of epididymal white adipose tissue showed naringenin supplementation reduced adipocyte size and number. Between 6 and 8 weeks of diet, mice were assessed in metabolic cages. Naringenin supplementation had no effect on food intake, ambulatory activity or energy expenditure during both the light and dark cycles. Consistently, naringenin-treated mice had significantly lower RER compared to mice fed chow alone (0.97 vs 0.99; P <0.05). This difference was driven by a significant suppression in RER during the light cycle (0.96 vs 1.00; P <0.05), but not the dark cycle (0.97 vs 0.98 N.S ), suggesting an enhanced starvation response. Triglyceride lipolysis was highest in white adipose tissue, followed by liver and muscle. Naringenin supplementation to chow increased the lipolytic rate in adipose, but not in muscle or liver, suggesting reduced adiposity was related to increased expression of ATGL or HSL. In conclusion, compared to chow alone, naringenin supplementation reduced plasma lipids and decreased body weight via increased adipose tissue lipolysis and suppressed RER, with no change in energy expenditure.


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