Mitochondrial function after associating liver partition and portal vein ligation for staged hepatectomy in an experimental model.

BACKGROUND: Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a two-stage strategy to induce rapid regeneration of the remnant liver. The technique has been associated with high mortality and morbidity rates. This study aimed to evaluate mitochondrial function, biogenesis and morphology during ALPPS-induced liver regeneration. METHODS: Male Wistar rats (n = 100) underwent portal vein ligation (PVL) or ALPPS. The animals were killed at 0 h (without operation), and 24, 48, 72 or 168 h after intervention. Regeneration rate and proliferation index were assessed. Mitochondrial oxygen consumption and adenosine 5'-triphosphate (ATP) production were measured. Mitochondrial biogenesis was evaluated by protein level measurements of peroxisome proliferator-activated receptor γ co-activator (PGC) 1-α, nuclear respiratory factor (NRF) 1 and 2, and mitochondrial transcription factor α. Mitochondrial morphology was evaluated by electron microscopy. RESULTS: Regeneration rate and Ki-67 index were significantly raised in the ALPPS group compared with the PVL group (regeneration rate at 168 h: mean(s.d.) 291·2(21·4) versus 245·1(13·8) per cent, P < 0·001; Ki-67 index at 24 h: 86·9(4·6) versus 66·2(4·9) per cent, P < 0·001). In the ALPPS group, mitochondrial function was impaired 48 h after the intervention compared with that in the PVL group (induced ATP production); (complex I: 361·9(72·3) versus 629·7(165·8) nmol per min per mg, P = 0·038; complex II: 517·5(48·8) versus 794·8(170·4) nmol per min per mg, P = 0·044). Markers of mitochondrial biogenesis were significantly lower 48 and 72 h after ALPPS compared with PVL (PGC1-α at 48 h: 0·61-fold decrease, P = 0·045; NRF1 at 48 h: 0·48-fold decrease, P = 0·028). Mitochondrial size decreased significantly after ALPPS (0·26(0·05) versus 0·40(0·07) µm2 ; P = 0·034). CONCLUSION: Impaired mitochondrial function and biogenesis, along with the rapid energy-demanding cell proliferation, may cause hepatocyte dysfunction after ALPPS. Surgical relevance Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a well known surgical strategy that combines liver partition and portal vein ligation. This method induces immense regeneration in the future liver remnant. The rapid volume increase is of benefit for resectability, but the mortality and morbidity rates of ALPPS are strikingly high. Moreover, lagging functional recovery of the remnant liver has been reported recently. In this translational study, ALPPS caused an overwhelming inflammatory response that interfered with the peroxisome proliferator-activated receptor γ co-activator 1-α-coordinated, stress-induced, mitochondrial biogenesis pathway. This resulted in the accumulation of immature and malfunctioning mitochondria in hepatocytes during the early phase of liver regeneration (bioenergetic destabilization). These findings might explain some of the high morbidity if confirmed in patients.

Does exercise reduce brain oxidative stress? A systematic review.

The aim of the present systematic review was to investigate the influence of different exercise programs on brain oxidative stress. A search of the literature was conducted up to 1 December 2012 across five databases: PUBMED, SCOPUS, SPORTS DISCUS, Web of Science, and The Cochrane Library. The search strategy used in the electronic databases mentioned was established as: (swim* OR exercise OR training) AND ("oxidative stress" AND brain) for each database. A methodological quality assessment valuation/estimation was additionally carried out in the final sample of studies. Of 1553 potentially eligible papers, 19 were included after inclusion and exclusion criteria. The methodological quality assessment showed a total score in the Quality Index between 40% and 80%, with a mean quality of 56.8%. Overall, regular moderate aerobic exercise appears to promote antioxidant capacity on brain. In contrast, anaerobic or high-intensity exercise, aerobic-exhausted exercise, or the combination of both types of training could deteriorate the antioxidant response. Future investigations should be focused on establishing a standardized exercise protocol, depending on the exercise metabolism wanted to test, which could enhance the objective knowledge in this topic.

Brain-derived neurotrophic factor treatment increases the skeletal muscle glucose transporter 4 protein expression in mice.

The purpose of the present study was to investigate whether peripheral brain-derived neurotrophic factor (BDNF) treatment induced metabolic adaptations in mouse skeletal muscle. BDNF (20 mg/kg/day) was injected subcutaneously for successive 14 days. BDNF treatment significantly reduced the total food intake and inhibited the weight gain in comparison to the control group. The glucose transporter 4 (GLUT4) protein expression in the gastrocnemius muscle was significantly increased by BDNF treatment in comparison to the control and pair-fed groups. Neither the oxidative nor the glycolytic enzyme activities in the gastrocnemius muscle changed after the BDNF treatment. These results suggest that the peripheral BDNF treatment promotes the skeletal muscle GLUT4 protein expression as well as hypophagia.

The effect of exercise and oxidant-antioxidant intervention on the levels of neurotrophins and free radicals in spinal cord of rats.

STUDY DESIGN: This study was designed to investigate the effects of oxidant and antioxidant treatment, as well as regular exercise, on neurotrophin levels in the spinal cord of rats. OBJECTIVES: Reactive oxygen species (ROS) play a role in neurodegenerative diseases, but ROS at moderate levels could stimulate biochemical processes through redox-sensitive transcription. METHODS: Exercised or sedentary animals were injected subcutaneously with hydrogen peroxide (H(2)O(2)), N-tert butyl-alpha-phenyl nitrone (PBN) or saline for the last 2 weeks of a 10-week experimental period to challenge redox balance. Free radical (FR) concentration was evaluated in the spinal cord by electron spin resonance, protein carbonyls, brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) levels and the mRNA expression of BDNF receptor and tyrosine kinase receptor B (TrKB). SETTING: Research Institute of Sport Science, Semmelweis University, Budapest, Hungary. RESULTS: Exercise or PBN decreased the concentration of FR, whereas the carbonyl content did not change. BDNF was significantly decreased in exercised sham and sedentary PBN-treated groups, and its content correlated with the level of FR. GDNF was significantly increased in sedentary H(2)O(2)-treated groups. No differences were observed in TrkB mRNA expression among groups. CONCLUSIONS: Results suggest that regular exercise alone and PBN in sedentary animals can successfully decrease FR levels in the spinal cord. Redox alteration seems to affect the levels of GDNF and BDNF, which might have clinical consequences, as neurotrophins play an important role in cellular resistance and regeneration.

Muscle soreness-induced reduction in force generation is accompanied by increased nitric oxide content and DNA damage in human skeletal muscle.

We examined the effect of exercise-induced muscle soreness on maximal force generation, tissue nitric oxide (NO) and 8-hydroxydeoxyguanosine (8-OHdG) content in human skeletal muscle. Female volunteers were assigned to control (C) and muscle soreness (MS) groups (n = 6 in each). MS group performed 200 eccentric muscle actions of the rectus femoris to induce muscle soreness. Maximal force generation was measured 24 h before and after exercise in both groups. Needle biopsy samples were assayed for NO content with electron spin resonance spectroscopy after ex vivo spin trapping, and 8-OHdG content were measured with an enzyme-linked immuno assay. Maximal force decreased by 11+/-5.4% (p < .05) 24 h after exercise in MS group. Muscle soreness increased NO and 8-OHdG contents from their control values of 0.39+/-0.08 arbitrary units and 0.035+/-0.004 pmol/micromol DNA to 0.96+/-0.05 (p < .05) arbitrary units and 0.044+/-0.005 (p < .05) pmol/micromol DNA, respectively. This is the first demonstration that muscle soreness-induced decrease in maximal force generation is a result of an increase in muscular NO content and associated with enhanced formation of 8-OHdG in human skeletal muscle.

High altitude training increases reactive carbonyl derivatives but not lipid peroxidation in skeletal muscle of rats.

The oxidative stress related consequences of physical training at high altitude are not known. The hypothesis was tested that physical training and exposure to high altitude have adverse effects on free radical generation and activities of antioxidant enzymes. The present results showed that 4 weeks of exercise at an altitude of 4000 m increased the activity of Mn-SOD in both white and red types of skeletal muscle. The activities of Cu,Zn-SOD, catalase, and glutathione peroxidase, as well as the level of lipid peroxidation measured by TBARS and lipid hydroperoxides, did not change significantly. In contrast, the level of reactive carbonyl derivatives measured by anti-2,4-dinitrophenylhydrazone antibodies and spectrophotometry showed an increase in both types of muscle of altitude trained rats compared with sea level trained and control groups. It was suggested that the oxidative modification of certain amino acids is due to the increasing gap between activity of SOD and peroxide scavenging enzymes, which results in increases in the number of hydrogen peroxide molecules. Thus, since the mechanism of generation and/or the mode of action of radicals resulting in lipid peroxidation and protein oxidation appears to be different in vivo, both processes should be studied during oxidative stress.

The effect of exercise training on oxidative damage of lipids, proteins, and DNA in rat skeletal muscle: evidence for beneficial outcomes.

Moderate daily exercise is known to be beneficial to health, reducing risks of a number of age-related disorders. Molecular mechanisms that bring about these effects are not clear. In contrast, it has been claimed that some types of prolonged physical exertion are detrimental to health because active oxygen species are generated excessively by enhanced oxygen consumption. Using two age groups of rats, young (4 week) and middle aged (14 months), we investigated the effects of long-term swimming training on the oxidative status of phospholipids, proteins, and DNA. The concentration of thiobarbituric acid reactive substances and 4-hydroxynonenal protein adducts did not differ in the gastrocnemius muscle between exercised and nonexercised animals in the two age groups. The extent of carbonylation in a protein of molecular weight around 29 KDa and the amount of 8-hydroxydeoxyguanosine in nuclear DNA were smaller (p<.05) in the exercised rats than in the sedentary animals. Activities of DT-diaphorase (C1: 29.3+/-1.9; C2: 36.1+/-2.6; E1: 27.2+/-1.3; C2: 33.4+/-2.9 nmol/mg protein) and proteasome, a major proteolytic enzyme for oxidatively modified proteins were significantly higher in the exercised animals of both age groups (p<.05). The adaptive response against oxidative stress induced by moderate endurance exercise constitutes a beneficial effect of exercise.

Carbonylated proteins in aging and exercise: immunoblot approaches.

Protein carbonyls were studied in aging and exercise by immunoblot followed by one- or two-dimensional polyacrylamide gel electrophoresis using antibodies against 2,4-dinitrophenylhydrazones. Proteins of rat kidneys exhibited significant age-related increase in the amount of carbonyl while those of the brain and liver did not. Major carbonylated proteins in the kidney included serum albumin. In nematodes in which protein carbonyls increased with age, one of the carbonylated proteins was identified as vitellogenin, an egg-yolk protein. A possible biological significance of this protein present in abundance even after egg-laying stages is discussed in terms of protection against oxidative stress. Exhaustive exercise induced significant increase in the carbonylation of selected but unidentified proteins in the lung. This oxidative stress might be caused by xanthine oxidase in this tissue and hypoxanthine derived from ATP-depleted muscles. Exercise at high altitude caused higher carbonylation of the skeletal muscle proteins, most notably a protein likely to be actin, than that at sea level but no significant difference was observed in lipid peroxidation. These studies emphasize the value of immunoblot analysis of tissue protein carbonyls in a variety of situations where oxidative stress is likely involved.

Regular exercise improves cognitive function and decreases oxidative damage in rat brain.

The biochemical mechanisms by which regular exercise significantly benefits health and well being, including improved cognitive function, are not well understood. Four-week-old (young) and 14-month-old (middle aged) Wistar rats were randomly assigned to young control and young exercised, middle-aged control and middle-aged exercised groups. Exercise groups were exposed to a swimming regime of 1 h a day, 5 days a week for 9 weeks. The passive avoidance test showed that middle-aged exercised rats had significantly (P<0.05) better short- (24 h) and long-term (72 h) memory than aged-matched control rats. Conditioned pole-jumping avoidance learning was improved markedly in both age groups by exercise. Brain thiobarbituric acid-reactive substances and 8-hydroxy-2'deoxyguanosine content in the DNA did not change significantly, while the protein carbonyl levels decreased significantly (P<0.05) in both exercised groups. This decrease was accompanied by an increase in the chymotrypsin-like activity of proteasome complex in the exercised groups, whereas trypsin-like activity did not differ significantly between all groups. The DT-diaphorase activity increased significantly (P<0.05) in the brain of young exercised animals. These data show that swimming training improves some cognitive functions in rats, with parallel attenuation of the accumulation of oxidatively damaged proteins.

Single bout of exercise eliminates the immobilization-induced oxidative stress in rat brain.

We were interested in the effects of immobilization (IM), a single bout of exercise (E) and immobilization followed by exercise (EIM) on memory and oxidative damage of macromolecules in hippocampus of rat brain. Eight hours of IM resulted in impairment of passive avoidance test (memory retrieval deficit) and increased latency to start locomotion in an open-field test. Two hours of swimming did not significantly alter the memory retrieval deficit and latency, while the EIM group had longer latency and similar memory than control and E groups. The oxidative damage of lipids, proteins and nuclear DNA increased significantly in IM group and no increase was observed in E and EIM animals. The activity of proteasome was not altered in any groups. The activity of glutamine synthetase (GS) was decreased in IM group (P < 0.05), this down regulation was not observed in E and EIM groups. These data suggest that oxidative damage of macromolecules is associated with impaired cognitive function. Single bout of exercise after immobilization eliminates the oxidative damage of macromolecules and normalizes memory function, probably by its ability to restore the activity level of GS and eliminate the consequences of immobilization-induced prolonged efflux of glutamate.

Implications of protein degradation in aging.

Aging is characterized by accumulation of potentially harmful altered proteins that could lead to gradual deterioration of cellular functions and eventually result in increased probability of death. Metabolic turnover of proteins thus plays an essential role in maintaining the life of an organism. In this article we summarize our current knowledge on age-related changes in protein turnover with special reference to degradation. Increase in half-life of proteins with advancing age is well documented. Qualitative rather than quantitative changes of proteasomes appear to be responsible for this change. Dietary restriction and moderate long-term exercise seem to restore higher proteasome activity and turnover rate of proteins in aged animals.

Relationship between cold tolerance and generation of suppressor macrophages during acute cold stress.

Acute cold stress induces suppressor macrophages expressing large numbers of receptors to the crystallizable fragment (Fc) portion of immunoglobulin G (MAC-1+ FcgammaRII/IIIbright cells), resulting in the immunosuppression of splenocyte mitogenesis. The generation of MAC-1+ FcgammaRII/IIIbright cells is mediated by the action of glucocorticoids (GCs) through the GC-receptor. In the present study, the generation of MAC-1+ FcgammaRII/IIIbright cells in peritoneal exudate cells was closely related to the decrease of rectal temperature during 3-day exposure to 5 degrees C. We next investigated the effects of improved cold tolerance on the generation of MAC-1+ FcgammaRII/IIIbright cells during acute cold stress. Mice were adapted to cold by exposure to 5 degrees C for 3 wk (cold-acclimated mice) and then reexposed to 5 degrees C for 3 h (acute cold stress) after living at 25 degrees C for 24 h. The rectal temperature of cold-acclimated mice was not decreased by the acute cold stress. In addition, the proportion of MAC-1+ FcgammaRII/IIIbright cells in peritoneal exudate cell population from cold-acclimated mice was unaffected by the acute cold stress. The cold acclimation significantly attenuated the increases in serum corticosterone levels and the expression of the GC-receptor mRNA on peritoneal exudate cells in response to acute cold stress. These results suggest that the altered GC response to acute cold stress by the improvement of cold tolerance inhibits the generation of suppressor macrophages during acute cold stress.

Superoxide dismutase derivative reduces oxidative damage in skeletal muscle of rats during exhaustive exercise.

A superoxide dismutase derivative (SM-SOD) that circulates and is bound to albumin with a half-life of 6 h was injected intraperitoneally into rats before exhaustive treadmill running to study its antioxidant scavenging capacity in the plasma and soleus and tibialis muscles. The exercise induced a marked increase in xanthine oxidase activity in plasma and an increase in thiobarbituric acid-reactive substances in the plasma as well as in the soleus and tibialis muscles of nonadministered rats immediately after the exercise. The immunoreactive content and activity of both SOD isoenzymes (Cu,Zn-SOD and Mn-SOD) of the nonadministered rats increased in the soleus and tibialis muscles immediately after running. SM-SOD treatment definitely attenuated the degree of the increase in thiobarbituric acid-reactive substances and xanthine oxidase in all samples examined immediately after exercise. Glutathione peroxidase activity significantly increased in the soleus muscle of nonadministered rats 1 day after running, whereas catalase activity remained unchanged throughout the experimental period. These results suggest that a single bout of exhaustive exercise induces oxidative stress in skeletal muscle of rats and that this oxidative stress can be attenuated by exogenous SM-SOD.

Adaptation to exercise-induced oxidative stress: from muscle to brain.

Exercise increases the generation of reactive oxygen and nitrogen species (RONS) and by causing adaptation, could decrease the incidence of RONS-associated diseases. A single bout of exercise, depending upon intensity and duration, can cause an increase in antioxidant enzyme activity, decrease levels of thiols and antioxidant vitamins, and result in oxidative damage as a sign of incomplete adaptation. Increased levels of RONS and oxidative damage are initiators of a specific adaptive response, such as the stimulation of the activation of antioxidant enzymes, thiols, and enhanced oxidative damage repair. Regular exercise has the capability to develop compensation to oxidative stress, resulting in overcompensation against the increased level of RONS production and oxidative damage. Regular exercise causes adaptation of the antioxidant and repair systems, which could result in a decreased base level of oxidative damage and increased resistance to oxidative stress.

Changes in urine 8-hydroxydeoxyguanosine levels of super-marathon runners during a four-day race period.

We have determined the urinary 8-hydroxydeoxyguanosine (8-OHdG) levels of five well trained supra-marathon runners during a four-day race. The daily running distances of the four-day race were the following; 93 km, 120 km, 56 km and 59 km, respectively. Pre-race and post-race urine samples were collected on each day and analyzed by a monoclonal antibody technique. The urinary 8-OHdG content increased significantly on the first day and tended to decrease from the third day. By the fourth day 8-OHdG content was significantly less than measured on the first three days. The serum creatine kinase activity changed in a similar fashion, showing a large increase (P<0.001) up to the third day when it decreased significantly from the peak value (P<0.05). We conclude that extreme physical exercise causes oxidative DNA damage to well trained athletes. However, repeated extreme exercise-induced oxidative stress does not propagate on increase of urinary 8-OHdG, but rather causes an adaptation leading to normalization of oxidative DNA damage.

The effect of high altitude and caloric restriction on reactive carbonyl derivatives and activity of glutamine synthetase in rat brain.

Both exposure to high altitude (HA) and caloric restriction (CR) may influence free radical generation. The aim of the present study was to evaluate the effects of 4 wk chronic exposure to 4,000m of HA and CR (60% of CR of control (C) rats) on protein oxidation in brain. Eighteen rats with similar body mass were assigned to CR, HA and C rats. Reactive carbonyl derivatives (RCD), marker of protein oxidation, were measured by Western blot. In addition, the activity and protein content of glutamine synthetase (GS) were determined. The body mass of C rats was significantly higher (P< 0.001) than that of HA and CR groups. The quantified signal intensity of RCD was significantly stronger in C rats than in HA and CR rats. The activity of GS was significantly increased in CR rats, while the protein content of GS was decreased in HA rats compared to C group. The data suggest that both HA and CR decreases the accumulation of RCD in the brain, however the mechanism of the decrease seems to be different during HA and CR.

Telomerase activity is not altered by regular strenuous exercise in skeletal muscle or by sarcoma in liver of rats.

Telomerase is a specialized ribonucleoprotein enzyme complex which prevents the loss of the telomere. The activity of telomerase can be up- and down-regulated by various oxidative stresses but the effect of physical exercise is not known, whereas the modifying effect of cancer on telomerase activity is well documented. In the first study, we investigated the effect of mild and strenuous exercise training on telomerase activity, assessed by a PCR ELISA kit. No alteration in telomerase activity was detected. In the second investigation, solid sarcoma cells were transplanted to control, exercise trained or exercise trained and still exercising mice. On the 16th day after the transplantation, the size of tumors in the exercise trained group was 72% and in the exercising group 57% (P < 0.05) of that in the controls. Telomerase activity and 8-hydroxy-2'-deoxyguanosine levels in the liver were not significantly altered by exercise and/or sarcoma. We conclude that mild and strenuous exercise training does not significantly affect the activity of telomerase in the systems studied. Exercise training during sarcoma significantly retards the development of tumors and could possibly serve as a positive adjunct to treatment.

Optimized biogas-fermentation by neural network control.

In this work several feed-forward back-propagation neural networks (FFBP) were trained in order to model, and subsequently control, methane production in anaerobic digesters. To produce data for the training of the neural nets, four anaerobic continuous stirred tank reactors (CSTR) were operated in steady-state conditions at organic loading rates (Br) of about 2 kg x m(-3) x d(-1) chemical oxygen demand (COD), and disturbed by pulse-like increase of the organic loading rate. For the pulses additional carbon sources were added to the basic feed (surplus- and primary sludge) to simulate cofermentation and to increase the COD. Measured parameters were: gas composition, methane production rate, volatile fatty acid concentration, pH, redox potential, volatile suspended solids and COD of feed and effluent. A hierarchical system of neural nets was developed and embedded in a Decision Support System (DSS). A 3-3-1 FFBP simulated the pH with a regression coefficient of 0.82. A 9-3-3 FFBP simulated the volatile fatty acid concentration in the sludge with a regression coefficient of 0.86. And a 9-3-2 FFBP simulated the gas production and gas composition with a regression coefficient of 0.90 and 0.80 respectively. A lab-scale anaerobic CSTR controlled by this tool was able to maintain a methane concentration of about 60% at a rather high gas production rate of between 5 to 5.6 m3 x m(-3) x d(-1).

The redox-associated adaptive response of brain to physical exercise.

Reactive oxygen species (ROS) are continuously generated during metabolism. ROS are involved in redox signaling, but in significant concentrations they can greatly elevate oxidative damage leading to neurodegeneration. Because of the enhanced sensitivity of brain to ROS, it is especially important to maintain a normal redox state in brain and spinal cord cell types. The complex effects of exercise benefit brain function, including functional enhancement as well as its preventive and therapeutic roles. Exercise can induce neurogenesis via neurotrophic factors, increase capillarization, decrease oxidative damage, and enhance repair of oxidative damage. Exercise is also effective in attenuating age-associated loss in brain function, which suggests that physical activity-related complex metabolic and redox changes are important for a healthy neural system.

Correlations of psycho-physiological parameters influencing the physical fitness of aged women.

Regular assessment of psycho-physiological parameters in aged subjects helps to clarify physical and mental conditions which are important in the prevention of health-endangering events to assure a healthy aging. Thirty older care female residents consented voluntarily to participate in the study. The somatic and psycho-physiological parameters recorded were handgrip force, disjunctive reaction time, balance control and whole body movement coordination, the electrocardiogram and heart rate variability. Significant correlations were found between (a) reaction time and balance control efficiency (r = -0.567, p < 0.009), (b) reaction time and movement coordination accuracy (r = -0.453, p < 0.045), (c) cardiac state and movement coordination accuracy (r = 0.545, p < 0.016), (d) cardiac stress and cardiac state (r = -0.495, p < 0.031), and (e) cardiac stress and force (r = -0.822, p < 0.045). In conclusion, for the aim of establishing basic battery tests for assessing psycho-physiological condition of physical fitness our results emphasize the importance of systematic physical activity, endurance and strength training supporting muscle force, balance control and whole-body movement coordination, in addition to improving the cardiac stress index level. The strong interrelation among these parameters allows the drawing of a more complete view regarding the health condition of aged individuals.