Effect of hypoenergetic feeding and refeeding on muscle and mononuclear cell activities of mitochondrial complexes I--IV in enterally fed rats

Reduced metabolic capacity in fast and slow skeletal muscle via oxidative stress and the energy-sensing of AMPK/SIRT1 in malnutrition

The effects of malnutrition on skeletal muscle result in not only the loss of muscle mass but also fatigue intolerance. It remains unknown whether the metabolic capacity is related to the fiber type composition of skeletal muscle under malnourished condition although malnutrition resulted in preferential atrophy in fast muscle. The purpose of the present study was to investigate the effects of metabolic capacity in fast and slow muscles via the energy-sensing of AMPK and SIRT1 in malnutrition. Wistar rats were randomly divided into control and malnutrition groups. The rats in the malnutrition group were provided with a low-protein diet, and daily food intake was limited to 50% for 12 weeks. Malnutrition with hypoalbuminemia decreased the body weight and induced the loss of plantaris muscle mass, but there was little change in the soleus muscle. An increase in the superoxide level in the plasma and a decrease in SOD-2 protein expression in both muscles were observed in the malnutrition group. In addition, the expression level of AMPK in the malnutrition group increased in both muscles. Conversely, the expression level of SIRT1 decreased in both muscles of the malnutrition group. In addition, malnutrition resulted in a decrease in the expression levels of PGC-1α and PINK protein, and induced a decrease in the levels of two key mitochondrial enzymes (succinate dehydrogenase and citrate synthase) and COX IV protein expression in both muscles. These results indicate that malnutrition impaired the metabolic capacity in both fast and slow muscles via AMPK-independent SIRT1 inhibition induced by increased oxidative stress.

Fast digestive, leucine-rich, soluble milk proteins improve muscle protein anabolism, and mitochondrial function in undernourished old rats

SCOPE

One strategy to manage malnutrition in older patients is to increase protein and energy intake. Here, we evaluate the influence of protein quality during refeeding on improvement in muscle protein and energy metabolism.

METHODS AND RESULTS

Twenty-month-old male rats (n = 40) were fed 50% of their spontaneous intake for 12 weeks to induce malnutrition, then refed ad libitum with a standard diet enriched with casein or soluble milk proteins (22%) for 4 weeks. A 13C-valine was infused to measure muscle protein synthesis and expression of MuRF1, and MAFbx was measured to evaluate muscle proteolysis. mTOR pathway activation and mitochondrial function were assessed in muscle. Malnutrition was associated with a decrease in body weight, fat mass, and lean mass, particularly muscle mass. Malnutrition decreased muscle mTOR pathway activation and protein FSR associated with increased MuRF1 mRNA levels, and decreased mitochondrial function. The refeeding period partially restored fat mass and lean mass. Unlike the casein diet, the soluble milk protein diet improved muscle protein metabolism and mitochondrial function in old malnourished rats.

CONCLUSIONS

These results suggest that providing better-quality proteins during refeeding may improve efficacy of renutrition in malnourished older patients.

Energy, Protein, Carbohydrate, and Lipid Intakes and Their Effects on Morbidity and Mortality in Critically Ill Adult Patients: A Systematic Review

The guidelines for nutritional support in critically ill adult patients differ in various aspects. The optimal amount of energy and nutritional substrates supplied is important for reducing morbidity and mortality, but unfortunately this is not well known, because the topic is complex and every patient is individual. The aim of this review was to gather recent pertinent information concerning the nutritional support of critically ill patients in the intensive care unit (ICU) with respect to the energy, protein, carbohydrate, and lipid intakes and the effect of their specific utilization on morbidity and mortality. Enteral nutrition (EN) is generally recommended over parenteral nutrition (PN) and is beneficial when administered within 24-48 h after ICU admission. In contrast, early PN does not provide substantial advantages in terms of morbidity and mortality, and the time when it is safe and beneficial remains unclear. The most advantageous recommendation seems to be administration of a hypocaloric (<20 kcal · kg^-1 · d^-1), high-protein diet (amino acids at doses of ≥2 g · kg^-1 · d^-1), at least during the first week of critical illness. Another important factor for reducing morbidity is the maintenance of blood glucose concentrations at 120-150 mg/dL, which is accomplished with the use of insulin and lower doses of glucose of 1-2 g · kg^-1 · d^-1, because this prevents the risk of hypoglycemia and is associated with a better prognosis according to recent studies. A fat emulsion is used as a source of required calories because of insulin resistance in the majority of patients. In addition, lipid oxidation in these patients is ∼25% higher than in healthy subjects.

Hypocaloric Feeding of the Critically Ill

During critical illness, the stress response causes accelerated gluconeogenesis and lipolysis, leading to hyperglycemia and elevated serum triglyceride levels. The traditional nutrition support strategy of meeting or exceeding calorie requirements may compound the metabolic alterations of the stress response. Hypocaloric nutrition support has the potential to provide nutrition support without exacerbating the stress response. Studies have shown hypocaloric nutrition support to be safe and to achieve nitrogen balance comparable with traditional regimens. Benefits shown include improved glycemic control, decreased intensive care unit (ICU) length of stay (LOS), and decreased ventilator days and infection rate; however, not all studies have produced identical results. Providing adequate dietary protein has emerged as an important factor in efficacy of the hypocaloric regimen. Although it is inconclusive, currently available research suggests that a nutrition support goal of 10-20 kcal/kg of ideal or adjusted weight and 1.5-2 g/kg ideal weight of protein may be beneficial during the acute stress response. Well-designed, randomized, controlled studies with adequate sample size that evaluate relevant clinical outcomes such as mortality, ICU LOS, and infection while controlling for factors such as glycemic control, severity of illness, incorporation of calories from all sources, in addition to feeding regimens, are needed to definitively determine the effects of hypocaloric nutrition support.

Impact of decreasing energy intakes in major burn patients: A 15-year retrospective cohort study

BACKGROUND & AIMS

Nutritional therapy is particularly important after major burn injury and specific nutritional guidelines have been developed. The study aimed at evaluating the impact of the changes in our nutritional practice, general compliance with the guidelines and potential consequences.

METHODS

Retrospective analysis of prospectively collected data in burn patients requiring intensive care (ICU) between 1999 and 2014.

INCLUSION CRITERIA

admission on day 1, full treatment and length of ICU stay >7 days. Four periods (P) were defined by protocol changes (P1: 1999-2001, P2: 2002-2005, P3: 2006-2010, P4: 2011-2014). Collected data: demographic and nutritional data, infectious complications, weights, CRP and prealbumin concentrations during the first 21 days.

RESULTS

240 patients were included (median age 43 years, burned area 25%). Measured energy expenditure (MEE) was stable through all periods but the prescribed caloric target decreased significantly, and below MEE (P1: 33 kcal/kg, IQR 7, P4: 28 kcal/kg, IQR 8, p < 0.001). Energy delivery ended decreasing below 30 kcal/kg/day (P1: 30 kcal/kg, IQR 23, P4: 25 kcal/kg, IQR 12, p < 0.001). Protein intakes increased due the use of high protein solutions and glutamine (P1: 1.04 g/kg, IQR 0.90, P4: 1.26, IQR 0.99, p < 0.001). Weight loss by day 21 increased significantly according to area under the curve (P1: 701, IQR 38, P2: 722, IQR 51, P4: 689 IQR 63, p = 0.02). Prealbumin levels decreased with energy decrease (P1: 150 mg/L, IQR 110, P4: 80 mg/L, IQR 70, p = 0.003).

CONCLUSIONS

The observed reduction of the energy delivery <30 kcal/kg was associated with a supplemental weight loss and lower prealbumin concentrations.

Selenium and zinc protect brain mitochondrial antioxidants and electron transport chain enzymes following postnatal protein malnutrition

AIMS

Selenium (Se) and zinc (Zn) are trace elements required for optimal brain functions. Thus, the role of Se and Zn against protein malnutrition induced oxidative stress on mitochondrial antioxidants and electron transport chain (ETC) enzymes from rats' brain were investigated.

MAIN METHODS

Normal protein (NP) and low protein (LP) rats were fed with diets containing 16% and 5% casein respectively for a period of 10weeks. Then the rats were supplemented with Se and Zn at a concentration of 0.15mgL(-1) and 227mgL(-1) in drinking water for 3weeks after which the rats were sacrificed.

KEY FINDINGS

The results obtained from the study showed significant (p<0.05) increase in lipid peroxidation (LPO), ROS production, oxidized glutathione (GSSG) levels and mitochondrial swelling and significant (p<0.05) reductions in catalase (CAT) and Mn-superoxide dismutase (Mn-SOD) activities, glutathione (GSH) levels, GSH/GSSG ratio and MTT reduction as a result of LP ingestion. The activities of mitochondrial ETC enzymes were also significantly inhibited in both the cortex and cerebellum of LP-fed rats. Supplementation with either Se or Zn restored the alterations in all the parameters.

SIGNIFICANCE

The study showed that Se and Zn might be beneficial in protecting mitochondrial antioxidants and ETC enzymes against protein malnutrition induced oxidative stress.

Permissive Underfeeding or Standard Enteral Feeding in Critically Ill Adults

BACKGROUND

The appropriate caloric goal for critically ill adults is unclear. We evaluated the effect of restriction of nonprotein calories (permissive underfeeding), as compared with standard enteral feeding, on 90-day mortality among critically ill adults, with maintenance of the full recommended amount of protein in both groups.

METHODS

At seven centers, we randomly assigned 894 critically ill adults with a medical, surgical, or trauma admission category to permissive underfeeding (40 to 60% of calculated caloric requirements) or standard enteral feeding (70 to 100%) for up to 14 days while maintaining a similar protein intake in the two groups. The primary outcome was 90-day mortality.

RESULTS

Baseline characteristics were similar in the two groups; 96.8% of the patients were receiving mechanical ventilation. During the intervention period, the permissive-underfeeding group received fewer mean (±SD) calories than did the standard-feeding group (835±297 kcal per day vs. 1299±467 kcal per day, P<0.001; 46±14% vs. 71±22% of caloric requirements, P<0.001). Protein intake was similar in the two groups (57±24 g per day and 59±25 g per day, respectively; P=0.29). The 90-day mortality was similar: 121 of 445 patients (27.2%) in the permissive-underfeeding group and 127 of 440 patients (28.9%) in the standard-feeding group died (relative risk with permissive underfeeding, 0.94; 95% confidence interval [CI], 0.76 to 1.16; P=0.58). No serious adverse events were reported; there were no significant between-group differences with respect to feeding intolerance, diarrhea, infections acquired in the intensive care unit (ICU), or ICU or hospital length of stay.

CONCLUSIONS

Enteral feeding to deliver a moderate amount of nonprotein calories to critically ill adults was not associated with lower mortality than that associated with planned delivery of a full amount of nonprotein calories. (Funded by the King Abdullah International Medical Research Center; PermiT Current Controlled Trials number, ISRCTN68144998.).

Effect of nutritional support on mitochondrial complex I activity in malnourished patients with anorexia nervosa

Previous studies have shown a reduction in lymphocyte mitochondrial complex I activity (CIA) in malnourished patients, which is restored after refeeding. Our aim was to evaluate the usefulness of CIA as an indicator of nutritional status in anorexia nervosa patients. Twelve malnourished anorexia nervosa females (mean age, 24.5 years) were admitted to the Eating Disorders Unit. Basal and weekly anthropometrics, bioelectric impedance (BIA), body composition, and CIA were performed until discharge. Patients were matched to 25 healthy females and refeeding was adjusted according to the Unit’s protocol. Statistics were used as appropriated and significance was reached at p < 0.05. Patients showed a significant reduction in body mass index, fat mass and fat free mass (FFM), triceps skinfold, and waist circumference on admission as compared with the control group. Parameters improved during hospitalization, but they failed to reach normal values at discharge. Compared with controls, CIA was significantly lower in patients on admission (2.16 vs. 5.68 nmol·min−1·mg protein−1). Refeeding and weight gain did not restore CIA. A positive association (r2= 0.69) was found between FFM and CIA in patients at discharge. Malnourished females with anorexia nervosa have lower CIA than controls that is not recovered after refeeding. This could be because of a low FFM exacerbated by physical inactivity while in hospital.

Lymphocytes mitochondrial physiology as biomarker of energy metabolism during fasted and fed conditions

Mitochondria are central coordinators of energy metabolism, and changes of their physiology have long been associated with metabolic disorders. Thus, observations of energy dynamics in different cell types are of utmost importance. Therefore, tools with quick and easy handling are needed for consistent evaluations of such interventions. In this paper, our main hypothesis is that during different nutritional situations lymphocytes mitochondrial physiology could be associated with the metabolism of other cell types, such as cardiomyocytes, and consequently be used as metabolic biomarker. Blood lymphocytes and heart muscle fibers were obtained from both fed and 24 h-fasted mice, and mitochondrial analysis was assessed by high-resolution respirometry and western blotting. Carbohydrate-linked oxidation and fatty acid oxidation were significantly higher after fasting. Carnitine palmitoil transferase 1 and uncouple protein 2 contents were increased in the fasted group, while the glucose transporters 1 and 4 and the ratio phosphorylated AMP-activated protein kinase/AMPK did not change between groups. In summary, under a nutritional status modification, mitochondria demonstrated earlier adaptive capacity than other metabolic sensors such as glucose transporters and AMPK, suggesting the accuracy of mitochondria physiology of lymphocytes as biomarker for metabolic changes.

Metabolic conditioning to attenuate the adverse effects of perioperative fasting and improve patient outcomes

PURPOSE OF REVIEW

To review recent articles, published between October 2009 and September 2011, that examined the adverse metabolic consequences of perioperative fasting and interventions that may be utilized to minimize these effects.

RECENT FINDINGS

Fasting induces metabolic stress and insulin resistance consequent upon effects on cellular mitochondria, gene and protein expression. Development of perioperative insulin resistance leads to increased postoperative morbidity and mortality. Preoperative carbohydrate loading attenuates insulin resistance via effects on cellular gene and protein expression, but its effects on clinical outcomes remain unclear. Perioperative arginine-supplemented diets were shown to be associated with significant reductions in infectious complications and length of hospital stay in patients undergoing elective surgery. Perioperative metabolic conditioning using glutamine and L-carnitine may be used to modulate insulin sensitivity but further studies need to determine whether these interventions result in clinical benefit. Finally, energy and protein provision to critically ill patients remains inadequate and is hampered by a number of factors including reliance on inaccurate means of estimating energy expenditure and enteral feed tolerance, conflicting data on the effects of energy deficit on clinical outcomes, and poor methodological quality of studies of perioperative nutritional interventions.

SUMMARY

Numerous perioperative interventions are available, which if utilized should help attenuate the adverse effects of perioperative fasting and lead to improved patient outcomes.

Short-term starvation and mitochondrial dysfunction - a possible mechanism leading to postoperative insulin resistance

BACKGROUND

Preoperative starvation results in the development of insulin resistance. Measures to attenuate the development of insulin resistance, such as preoperative carbohydrate loading, lead to clinical benefits. However, the mechanisms that underlie the development of insulin resistance during starvation and its attenuation by preoperative carbohydrate loading remain to be defined. Insulin resistance associated with type 2 diabetes and ageing has been linked to mitochondrial dysfunction. The metabolic consequences of preoperative starvation and carbohydrate loading and mechanisms linking insulin resistance to impaired mitochondrial function are discussed.

METHODS

Searches of the Medline and Science Citation Index databases were performed using various key words in combinations with the Boolean operators AND, OR and NOT. Key journals, nutrition and metabolism textbooks and the reference lists of key articles were also hand searched.

RESULTS

Animal studies have shown that short-term energy deprivation decreases mitochondrial ATP synthesis capacity and complex activity, and increases oxidative injury. Furthermore, evidence from human studies suggests that the development of insulin resistance during starvation may be linked to impaired mitochondrial function.

CONCLUSIONS

There is evidence from animal studies that short-term starvation causes mitochondrial dysfunction. Future studies should investigate whether mitochondrial dysfunction underlies the development of insulin resistance in patients undergoing elective surgery.

Does white wine qualify for French paradox? Comparison of the cardioprotective effects of red and white wines and their constituents: resveratrol, tyrosol, and hydroxytyrosol

It is generally believed that the French paradox is related to the consumption of red wine and not other varieties of wine, including white wine or champagne. Some recent studies have indicated that white wine could also be as cardioprotective as red wine. The present investigation compares the cardioprotective abilities of red wine, white wine, and their principal cardioprotective constituents. Different groups of rats were gavaged with red wine, white wine, resveratrol, tyrosol, and hydroxytyrosol. Red wine and its constituent resveratrol and white wine and its constituents tyrosol and hydroxytyrosol all showed different degrees of cardioprotection as evidenced by their abilities to improve postischemic ventricular performance, reduce myocardial infarct size and cardiomyocyte apoptosis, and reduce peroxide formation. It was discovered in this study that although each of the wines and their components increased the enzymatic activities of the mitochondrial complex (I-IV) and citrate synthase, which play very important roles in oxidative phosphorylation and ATP synthesis, some of the groups were more complex-specific in inducing the activity compared to the other groups. Cardioprotective ability was further confirmed by increased expression of phospho-Akt, Bcl-2, eNOS, iNOS, COX-1, COX-2, Trx-1, Trx-2, and HO-1. The results of this study suggest that white wine can provide cardioprotection similar to red wine if it is rich in tyrosol and hydroxytyrosol.

Nutrition support of the traumatically injured warfighter

Major trauma induces metabolic alterations that contribute to the systemic immune suppression in severely injured patients and increase the risk of infection and posttraumatic organ failure. Nutrition modulation of cellular processes has evolved into a high-priority therapy, backed by substantial scientific evidence. The appropriate selection, timing, and dose of nutrients required for metabolic resuscitation must be individualized and goal directed. Ideally, the nutritional interventions for warfighters will be developed strategically based on the extent of injuries and underlying deficiencies and will be designed to provide the nutrients necessary to balance hypermetabolic processes, heal wounds, and promote optimal recovery.

Activities of respiratory chain complexes in isolated platelets in females with anorexia nervosa

OBJECTIVE

A broad spectrum of endocrine and biochemical disturbances was observed in patients with anorexia nervosa. In addition, metabolic changes may concern the efficiency of mitochondrial energy generating system. In our study we analyzed the activities of respiratory chain complexes in females with anorexia nervosa.

METHOD

The activities of respiratory chain complexes I, II, IV, I + III, and citrate synthase serving as the control enzyme were measured spectrophotometrically in isolated platelets in 36 females with anorexia nervosa (BMI 15 +/- 1.7) at the age 18-35 years and in 37 age related female controls (BMI 21 +/- 2.2).

RESULTS

In females with anorexia nervosa, the activities of respiratory chain complexes I and II in isolated platelets were significantly higher in comparison with controls. No differences were found in the activities of complexes IV and I + III and citrate synthase.

CONCLUSION

Our results suggest higher efficiency of some respiratory chain complexes in platelets in females with anorexia nervosa.

Mitochondrial defects and oxidative damage in patients with peripheral arterial disease

Abnormal mitochondrial function is present in patients with peripheral arterial disease and may contribute to its clinical manifestations. However, the specific biochemical mitochondrial defects and their association with increased oxidative stress have not been fully characterized. Gastrocnemius muscle was obtained from peripheral arterial disease patients (n = 25) and age-matched controls (n = 16) and mitochondrial parameters were measured. Complexes I through IV of the electron transport chain were individually evaluated to assess for isolated defects. Muscle was also evaluated for protein and lipid oxidative changes by measuring the levels of protein carbonyls, lipid hydroperoxides, and total 4-hydroxy-2-nonenal binding and for the activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. Mitochondrial electron transport chain complexes I, III, and IV in arterial disease patients demonstrated significant reductions in enzymatic activities and mitochondrial respiration compared to controls. Oxidative stress biomarker analysis demonstrated significantly increased levels of protein carbonyls, lipid hydroperoxides, and 4-hydroxy-2-nonenal compared to control muscle. Antioxidant enzyme activities were altered, with a significant decrease in superoxide dismutase activity and significant increases in catalase and glutathione peroxidase. Peripheral arterial disease is associated with abnormal mitochondrial function and evidence of significant oxidative stress.

Effect of feeding malnourished patients for 1 mo on mitochondrial complex I activity and nutritional assessment measurements

BACKGROUND

We showed previously that the activity of complex I (the first enzyme of the electron transport chain) in peripheral blood mononuclear cells decreases with malnutrition and increases to a subnormal value after 1 wk of refeeding, but the traditional markers of nutritional status do not do so.

OBJECTIVE

The aim of this study was to ascertain whether a period of nutritional intervention longer than 1 wk would normalize complex I activity and traditional markers of nutritional status.

DESIGN

Fifteen malnourished patients (7 women and 8 men) with > or =10% body weight loss over the previous 6 mo were studied on the day of their admission to hospital and 7, 14 and 30 d after the beginning of nutritional support. Complex I activity in peripheral blood mononuclear cells, weight, height, body composition, body water compartments, dietary intake, and serum albumin concentrations were measured on each occasion. The results before and during nutritional intervention were compared with values obtained in 30 healthy volunteers (17 women and 13 men).

RESULTS

Complex I activity increased significantly after the first week of refeeding (P < 0.001) and reached a normal value after 1 mo of nutritional supplementation. Among the classic markers of nutritional status, only the ratio of extracellular water to intracellular water tended to decrease over the refeeding period.

CONCLUSION

Complex I activity increases rapidly and is normalized by refeeding at a time when other markers of nutritional status do not change significantly.

Effect of malnutrition and short-term refeeding on peripheral blood mononuclear cell mitochondrial complex I activity in humans

BACKGROUND

Previous investigations in rats have shown that the first enzyme of the mitochondrial electron transport chain (complex I) is altered in peripheral blood mononuclear cells (PBMCs) and muscle by dietary manipulations.

OBJECTIVE

We hypothesized that similar changes would occur in human PBMCs as a result of dietary malnutrition and short-term refeeding irrespective of the presence or absence of active inflammatory bowel disease (IBD).

DESIGN

Fourteen malnourished patients with active IBD, 13 malnourished patients without IBD, and 42 healthy subjects were investigated. Complex I activity, body mass index, body composition, energy and protein intakes, and resting energy expenditure were measured. Five patients without IBD and 6 patients with IBD were investigated after 7 d of refeeding.

RESULTS

In patients without IBD, weight loss was mainly due to a loss of fat mass. In contrast, weight loss in IBD patients was due to a loss of both fat-free mass and fat mass. Complex I activity was reduced to the same degree in both groups of patients and was significantly lower than that observed in healthy subjects. In both groups of patients, complex I activity correlated significantly with body weight, body mass index, percentage weight loss, and fat mass. Complex I activity increased significantly after 1 wk of refeeding in both groups of patients before observed changes of measured nutritional assessment indexes.

CONCLUSION

Our study showed that mitochondrial complex I activity measured in PBMCs seems to be a specific marker of dietary malnutrition and responds rapidly to refeeding.

Effect of hypoenergetic feeding on muscle oxidative phosphorylation and mitochondrial complex I-IV activities in rats

BACKGROUND

Previous studies showed that malnutrition reduces the activity of complexes I, II, and III in the mitochondria of skeletal muscle.

OBJECTIVE

We hypothesized that malnutrition would influence oxidative phosphorylation and mitochondrial complex activity in the skeletal muscle of rats.

DESIGN

Thirty-two rats were assigned either to a control group with an ad libitum intake of 364 kJ/d or to a hypoenergetic group with an intake of 92 kJ/d. Eleven of these rats received the hypoenergetic diet for 10 d, 2 for 5 d, 2 for 6 d, 2 for 7 d, and 1 each for 8 and 11 d to achieve a distributed weight loss. Ten controls were fed for 10 d, 2 for 7 d, and 1 for 5 d, to match day 10, day 5, and the midpoint (day 7) of 6-8 d of hypoenergetic feeding. The 2 diets provided the same volume, electrolytes, vitamins, and trace elements but different amounts of energy.

RESULTS

A significant relation was observed between weight loss and the state 4 and 3 oxidation rates with pyruvate + malate and for state 3 glutamate + malate and succinate + rotenone but not with tetramethyl-p-phenylenediamine + ascorbate + antimycin A (TMPD). Similarly, a significant relation was observed between the degree of weight loss and complex I and III activities but not with complex II and IV activities.

CONCLUSIONS

The complex activities of the mitochondrial oxidative phosphorylation chain in muscle were depressed selectively with energy deprivation when compared with normally fed rats. These findings may partly explain the mechanism of reduced muscle energetics in energy malnutrition.