Sara Ghezzal

Muscle mass optimization prevents experimental hepatic encephalopathy.

Sara Ghezzal, Marc-André Clément, Cristina R. Bosoi, Roxanne Beauchamp, Mélanie Tremblay, Christopher F. Rose, Chantal Bémeur.

Background: Malnutrition is an important prognostic factor potentially influencing clinical outcome of patients suffering from chronic liver disease (cirrhosis; CLD). Malnutrition exacerbates severe muscle loss and hepatic encephalopathy (HE) in cirrhotic patients. New management strategies focussing on improving nutritional status and attenuating CLD-related complications are an unmet clinical need. Aims: We hypothesize supplementation with branched-chain amino acid leucine (LEU) and exercise training (EX) could possibly attenuate muscle mass loss and prevent HE (characterized by brain edema as well as cognitive and psychomotor impairments) in CLD. Methods: CLD was induced in rats following 6-week bile-duct ligation (BDL). Five experimental groups were tested; 1) BDL; 2) BDL + LEU; 3) BDL + EX; 4) BDL + LEU + EX; 5) Sham-operated rats. One week following BDL, rats were submitted to 15 min EX (10 cm/s) every other day and BDL rats receiving LEU, were gavaged daily (1.35 mg/kg) for five weeks. Body weight, muscle (gastrocnemius) mass, metabolic state (calculation of energy expenditure independent of food intake and fecal mass), cerebral edema (specific gravity method) and cognitive/psychomotor function (open-field test; anxiety-like behavior assessment and novel object recognition test; memory testing) were measured in all groups. Results: BDL rats gained less body weight compared to sham-operated rats (125.0±24.9 g vs 226.0±38.5 g; P<0.05). LEU-treated BDL rats display an improvement in brain edema (78.50±0.03% vs 80.27±0.14%; P<0.05), muscle mass (5.48±0.90 g/kg vs 4.83±0.11 g/kg; P<0.05) and circumference (15.6±0.8 cm/kg vs 13.1±0.7 cm/kg ; P<0.05) and metabolic activity (27.48±1.15 vs 32.99±2.35; P<0.05), which was further ameliorated with EX, compared to BDL animals. In addition, BDL rats receiving LEU and EX exhibited less anxiety-like behavior (4.9±1.2 s vs 2.2±0.9 s passed in the center; P<0.01) as well as better novel object recognition memory (69.6±15.2% vs 25.4±9.6%; P<0.01), in comparison with BDL rats. Conclusions: Our results demonstrate that supplemental LEU along with EX reduces body weight and muscle mass loss, improves metabolic activity, attenuates brain edema and improve cognitive and psychomotor function. These findings suggest that strategies aiming at improving nutritional status will attenuate muscle mass loss, reduce the risk of developing HE and therefore improve quality of life and decrease mortality in CLD. LEU supplementation and EX could rapidly be translated into clinical practice. Funding Agency: CIHR.

Beneficial effects of muscle mass optimization using leucine supplementation and exercise training in the prevention of hepatic encephalopathy in experimental cirrhosis.

Chantal *Bémeur, Sara Ghezzal, Marc-André Clément, Cristina R. Bosoi, Roxanne Beauchamp, Mélanie Tremblay, Christopher F. Rose, Chantal Bémeur.

Oral

Optimizing muscle mass: therapeutic target to prevent experimental hepatic encephalopathy.

Chantal *Bémeur, Sara Ghezzal, Marc-André Clément, Cristina R. Bosoi, Roxanne Beauchamp, Mélanie Tremblay, Christopher F. Rose, Chantal Bémeur.

Background: Malnutrition is an important prognostic factor potentially influencing clinical outcome of patients suffering from chronic liver disease (cirrhosis; CLD). Malnutrition, considered a consequence of metabolic disturbances (hypermetabolism), exacerbates severe muscle loss and hepatic encephalopathy (HE) (complex neuropsychiatric disorder) in cirrhotic patients. New management strategies focussing on improving nutritional status and attenuating CLD-related complications are an unmet clinical need. We hypothesize supplementation with branched-chain amino acid leucine (LEU) and exercise training (EX) could possibly attenuate muscle mass loss and prevent HE (characterized by brain edema as well as cognitive and psychomotor impairments) in CLD. Methods: CLD was induced in rats following 6-week bile-duct ligation (BDL). Five experimental groups were tested; 1) BDL; 2) BDL + LEU; 3) BDL + EX; 4) BDL + LEU + EX; 5) Sham-operated rats. One week following BDL, rats were gavaged with LEU (1.35 mg/kg) daily and submitted to 15 min EX (10 cm/s) every other day for 5 weeks. Body weight, muscle (gastrocnemius) mass, metabolic state (calculation of energy expenditure independent of food intake and fecal mass), cerebral edema (specific gravity method) and cognitive/psychomotor function (open-field test; anxiety-like behavior assessment and novel object recognition test; memory testing) were measured. Results: BDL rats gained less body weight compared to sham-operated rats (125.0g ± 24.9 vs 226.0g ± 38.5; p<0.05). LEU-treated BDL rats display an improvement in brain edema (78.50% ± 0.03 vs 80.27% ± 0.14; p<0.05), muscle mass (5.48g/kg ± 0.90 vs 4.83g/kg ± 0.11; p<0.05) and circumference (15.6cm/kg ± 0.8 vs 13.1cm/kg ± 0.7; p<0.05) and metabolic activity (27.48 ± 1.15 vs 32.99 ± 2.35; p<0.05), which was further ameliorated with EX, compared to BDL animals. In addition, BDL rats receiving LEU and EX exhibited less anxiety-like behavior (4.9s ± 1.2 vs 2.2s ± 0.9 passed in the center; p<0.01) as well as better novel object recognition memory (69.6 ± 15.2% vs 25.4 ± 9.6%; p<0.01), in comparison with BDL rats. Conclusion: Our results demonstrate that supplemental LEU along with EX recovers body weight loss, increases muscle mass, improves metabolic activity, attenuates brain edema and improves cognitive and psychomotor function. These findings suggest that strategies aiming at improving nutritional status will attenuate muscle mass loss and reduce the risk of developing HE. This in turn will improve quality of life, decrease mortality and enhance outcome post-liver transplantation. LEU supplementation and EX could rapidly be translated into clinical practice.

Beneficial effects of muscle mass optimization using leucine supplementation and exercise training in the prevention of hepatic encephalopathy in experimental cirrhosis.

Chantal *Bémeur, Sara Ghezzal, Marc-André Clément, Cristina R. Bosoi, Roxanne Beauchamp, Mélanie Tremblay, Christopher F. Rose, Chantal Bémeur.

Background: Malnutrition is an important prognostic factor potentially influencing clinical outcome of patients suffering from chronic liver disease (cirrhosis; CLD). Malnutrition, considered a consequence of metabolic disturbances (hypermetabolism), exacerbates severe muscle loss and hepatic encephalopathy (complex neuropsychiatric disorder) in cirrhotic patients. New management strategies focussing on improving nutritional status and attenuating CLD-related complications are an unmet clinical need. We hypothesize supplementation with branched-chain amino acid leucine (LEU) and exercise training (EX) could possibly attenuate muscle mass loss and prevent hepatic encephalopathy (characterized by brain edema as well as cognitive and psychomotor impairments) in CLD. Methods: CLD was induced in rats following 6-week bile-duct ligation (BDL). Five experimental groups were tested; 1) BDL; 2) BDL + LEU; 3) BDL + EX; 4) BDL + LEU + EX; 5) Sham-operated rats. One week following BDL, rats were submitted to 15 min EX (10 cm/s) every other day and BDL rats receiving LEU, were gavaged daily (1.35 mg/kg) for 5 weeks. Body weight, muscle (gastrocnemius) mass, metabolic state (calculation of energy expenditure independent of food intake and fecal mass), cerebral edema (specific gravity method) and cognitive/psychomotor function (open-field test; anxiety-like behavior assessment and novel object recognition test; memory testing) were measured in all groups. Results: BDL rats gained less body weight and muscle mass compared to sham-operated rats. LEU-treated BDL rats display an improvement in brain edema, muscle mass and circumference and metabolic activity, which was further ameliorated with EX. In addition, BDL rats receiving LEU and EX exhibited less anxiety-like behavior as well as better novel object recognition memory. Conclusion: Our results demonstrate that supplemental LEU along with EX reduces body weight and muscle mass loss, improves metabolic activity, attenuates brain edema and improve cognitive and psychomotor function. These findings suggest that strategies aiming at improving nutritional status will attenuate muscle mass loss, reduce the risk of developing hepatic encephalopathy and therefore improve quality of life and decrease mortality in CLD. LEU supplementation and EX could rapidly be translated into clinical practice.

Beneficial effects of muscle mass optimization using leucine supplementation and exercise training in the prevention of hepatic encephalopathy in experimental cirrhosis.

Sara Ghezzal, Marc-André Clément, Cristina R. Bosoi, Roxanne Beauchamp, Mélanie Tremblay, Christopher F. Rose, Chantal Bémeur.

Aims: The pathogenesis of hepatic encephalopathy (HE) is multifactorial. Even though ammonia is the central component in the pathogenesis of HE, oxidative stress is believed to play a role in exacerbating the neuropsychological effects of ammonia in patients with liver disease. With new, highly sensitive imaging techniques, brain edema is observed in HE patients. We previously demonstrated that portacaval shunted hyperammonemic rats do not develop oxidative stress or brain edema. In order to define a synergistic effect between hyperammonemia and systemic oxidative stress, the present study investigates the role of oxidative stress in the pathogenesis of brain edema in PCA rats following glutathione depletion by diethyl maleate (DEM). Methods: In the first set of experiments, we evaluated the effect of DEM in PCA and SHAM-operated control rats by injecting DEM at a dose of 0.4 and 1 mg/kg/day intraperitoneally for 10 days starting at day 18 after surgery. Rats were sacrificed at day 28 and oxidative stress was evaluated by arterial malon-dialdehyde (MDA, commercial kit). In the second set of experiments, 1 mg/kg/day DEM was used to induce oxidative stress. Ammonia (commercial kit) as well as other different oxidative stress markers: reactive oxygen species (DCFDA fluorescence technique), and 4-hydroxy-2-nonenal (HNE, Western blot) were assessed in arterial plasma and frontal cortex tissue. Brain water content was measured in the frontal cortex using a specific gravimetric technique. Results: DEM at 1 mg/kg/day (not 0.4 mg/kg/day) induced a significant increase in MDA levels in PCA rats. No increase in MDA was detected following either dose of DEM in SHAM-operated controls. Ammonia levels in both DEM-treated and non-treated PCA rats were significantly increased vs respective sham-operated controls (p<0.001) and remained unchanged between non-treated and DEM-treated PCA groups (p>0.05). An increase in brain water content was observed in DEM-treated PCA rats vs non-treated PCA rats (PCA+DEM: 78.45 ± 0.13% vs PCA: 77.38 ± 0.11, p< 0.001). Although no significant changes in reactive oxygen species were observed, there was an increase in plasma levels of HNE in DEM-treated PCA rats compared to non-treated PCA rats. No significant changes in any oxidative stress markers were observed in the frontal cortex. Conclusions: DEM treatment in PCA rats induced systemic oxidative stress but not central oxidative stress. This, imposed on hyperammonemia, was accompanied by the onset of brain edema in rats with PCA. Oxidative stress and brain edema were not detected in SHAM-operated rats, which were not hyperammonemic. Our findings suggest a synergistic effect between hyperammonemia and systemic oxidative stress is implicated in the pathogenesis of brain edema in hepatic encephalopathy.

Sara Ghezzal

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