Limits...
Role of choline deficiency in the Fatty liver phenotype of mice fed a low protein, very low carbohydrate ketogenic diet.

Schugar RC, Huang X, Moll AR, Brunt EM, Crawford PA - PLoS ONE (2013)

Bottom Line: C57BL/6J mice maintained on the two 5% kcal protein diets induced the most significant ketoses, which was only partially diminished by choline replacement.Key effects of the 5% kcal protein diet - weight loss, hepatic fat accumulation, and mitochondrial ultrastructural disarray and bioenergetic dysfunction - were mitigated by choline repletion.These studies indicate that synergistic effects of protein restriction and choline deficiency influence integrated metabolism and hepatic pathology in mice when nutritional fat content is very high, and support the consideration of dietary choline content in ketogenic diet studies in rodents to limit hepatic mitochondrial dysfunction and fat accumulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Center for Cardiovascular Research, Washington University, St. Louis, Missouri, USA.

ABSTRACT
Though widely employed for clinical intervention in obesity, metabolic syndrome, seizure disorders and other neurodegenerative diseases, the mechanisms through which low carbohydrate ketogenic diets exert their ameliorative effects still remain to be elucidated. Rodent models have been used to identify the metabolic and physiologic alterations provoked by ketogenic diets. A commonly used rodent ketogenic diet (Bio-Serv F3666) that is very high in fat (~94% kcal), very low in carbohydrate (~1% kcal), low in protein (~5% kcal), and choline restricted (~300 mg/kg) provokes robust ketosis and weight loss in mice, but through unknown mechanisms, also causes significant hepatic steatosis, inflammation, and cellular injury. To understand the independent and synergistic roles of protein restriction and choline deficiency on the pleiotropic effects of rodent ketogenic diets, we studied four custom diets that differ only in protein (5% kcal vs. 10% kcal) and choline contents (300 mg/kg vs. 5 g/kg). C57BL/6J mice maintained on the two 5% kcal protein diets induced the most significant ketoses, which was only partially diminished by choline replacement. Choline restriction in the setting of 10% kcal protein also caused moderate ketosis and hepatic fat accumulation, which were again attenuated when choline was replete. Key effects of the 5% kcal protein diet - weight loss, hepatic fat accumulation, and mitochondrial ultrastructural disarray and bioenergetic dysfunction - were mitigated by choline repletion. These studies indicate that synergistic effects of protein restriction and choline deficiency influence integrated metabolism and hepatic pathology in mice when nutritional fat content is very high, and support the consideration of dietary choline content in ketogenic diet studies in rodents to limit hepatic mitochondrial dysfunction and fat accumulation.

Show MeSH

Related in: MedlinePlus

Roles of varying protein and choline nutrient contents in very high fat, low protein, very low carbohydrate diet-induced hepatic steatosis.(A) Liver weight/body weight ratios after 6 weeks on the diets. n=5-10 mice/group. c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. See end of this legend for description of the individual comparisons depicted by each letter. (B) Biochemical quantification of hepatic TAG content, normalized to liver mass. n=5-10 mice/group. a, p≤0.05 for LP/C- and p≤0.01 for VLP/C-; b, p≤0.05; c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. (C) Serum alanine aminotransferase (ALT) concentrations. n=4-6 mice/group. c, p≤0.05. Data are presented as means±SEM. a, significant difference compared to chow; b, significant difference attributable to decrease in protein content (from 10% kcal to 5% kcal) at a fixed choline content; c, significant difference attributable to restriction in choline content (from 5.3 g/kg to 0.3 g/kg) at a fixed protein content; by 1-way ANOVA with Tukey’s post hoc testing.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3756977&req=5

pone-0074806-g002: Roles of varying protein and choline nutrient contents in very high fat, low protein, very low carbohydrate diet-induced hepatic steatosis.(A) Liver weight/body weight ratios after 6 weeks on the diets. n=5-10 mice/group. c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. See end of this legend for description of the individual comparisons depicted by each letter. (B) Biochemical quantification of hepatic TAG content, normalized to liver mass. n=5-10 mice/group. a, p≤0.05 for LP/C- and p≤0.01 for VLP/C-; b, p≤0.05; c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. (C) Serum alanine aminotransferase (ALT) concentrations. n=4-6 mice/group. c, p≤0.05. Data are presented as means±SEM. a, significant difference compared to chow; b, significant difference attributable to decrease in protein content (from 10% kcal to 5% kcal) at a fixed choline content; c, significant difference attributable to restriction in choline content (from 5.3 g/kg to 0.3 g/kg) at a fixed protein content; by 1-way ANOVA with Tukey’s post hoc testing.

Mentions: To determine the effects of dietary protein and choline levels on hepatic structure and function, we quantified hepatic mass and intrahepatic triglyceride content after 6 weeks on each diet. Mice fed either choline restricted diet (VLP/C- or LP/C-) exhibited liver weight to body weight ratios that were ~25% increased compared to mice fed the choline replete diets (LP/C+ and VLP/C+) (Figure 2A). Additionally, normalized liver weights of mice fed either choline replete paste diet were ~13% smaller compared to chow-fed mice. Hepatic TAG content in mice maintained on VLP/C- (21.5±4.2 mg/g tissue) was markedly higher than that of mice from any of the other paste diet cohorts (Figure 2B). Hepatic TAG content in mice maintained on the LP/C- diet was significantly higher than those of mice maintained on LP/C+, VLP/C+, or chow control, indicating that choline restriction in the context of a very high fat diet predisposes to increased hepatic TAG content and that this is exacerbated by severe protein limitation. Serum alanine ALT activities were significantly elevated in both cohorts maintained on the choline restricted diets, independent of protein content (Figure 2C).


Role of choline deficiency in the Fatty liver phenotype of mice fed a low protein, very low carbohydrate ketogenic diet.

Schugar RC, Huang X, Moll AR, Brunt EM, Crawford PA - PLoS ONE (2013)

Roles of varying protein and choline nutrient contents in very high fat, low protein, very low carbohydrate diet-induced hepatic steatosis.(A) Liver weight/body weight ratios after 6 weeks on the diets. n=5-10 mice/group. c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. See end of this legend for description of the individual comparisons depicted by each letter. (B) Biochemical quantification of hepatic TAG content, normalized to liver mass. n=5-10 mice/group. a, p≤0.05 for LP/C- and p≤0.01 for VLP/C-; b, p≤0.05; c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. (C) Serum alanine aminotransferase (ALT) concentrations. n=4-6 mice/group. c, p≤0.05. Data are presented as means±SEM. a, significant difference compared to chow; b, significant difference attributable to decrease in protein content (from 10% kcal to 5% kcal) at a fixed choline content; c, significant difference attributable to restriction in choline content (from 5.3 g/kg to 0.3 g/kg) at a fixed protein content; by 1-way ANOVA with Tukey’s post hoc testing.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756977&req=5

pone-0074806-g002: Roles of varying protein and choline nutrient contents in very high fat, low protein, very low carbohydrate diet-induced hepatic steatosis.(A) Liver weight/body weight ratios after 6 weeks on the diets. n=5-10 mice/group. c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. See end of this legend for description of the individual comparisons depicted by each letter. (B) Biochemical quantification of hepatic TAG content, normalized to liver mass. n=5-10 mice/group. a, p≤0.05 for LP/C- and p≤0.01 for VLP/C-; b, p≤0.05; c, p≤0.05 for LP/C- and p≤0.01 for VLP/C-. (C) Serum alanine aminotransferase (ALT) concentrations. n=4-6 mice/group. c, p≤0.05. Data are presented as means±SEM. a, significant difference compared to chow; b, significant difference attributable to decrease in protein content (from 10% kcal to 5% kcal) at a fixed choline content; c, significant difference attributable to restriction in choline content (from 5.3 g/kg to 0.3 g/kg) at a fixed protein content; by 1-way ANOVA with Tukey’s post hoc testing.
Mentions: To determine the effects of dietary protein and choline levels on hepatic structure and function, we quantified hepatic mass and intrahepatic triglyceride content after 6 weeks on each diet. Mice fed either choline restricted diet (VLP/C- or LP/C-) exhibited liver weight to body weight ratios that were ~25% increased compared to mice fed the choline replete diets (LP/C+ and VLP/C+) (Figure 2A). Additionally, normalized liver weights of mice fed either choline replete paste diet were ~13% smaller compared to chow-fed mice. Hepatic TAG content in mice maintained on VLP/C- (21.5±4.2 mg/g tissue) was markedly higher than that of mice from any of the other paste diet cohorts (Figure 2B). Hepatic TAG content in mice maintained on the LP/C- diet was significantly higher than those of mice maintained on LP/C+, VLP/C+, or chow control, indicating that choline restriction in the context of a very high fat diet predisposes to increased hepatic TAG content and that this is exacerbated by severe protein limitation. Serum alanine ALT activities were significantly elevated in both cohorts maintained on the choline restricted diets, independent of protein content (Figure 2C).

Bottom Line: C57BL/6J mice maintained on the two 5% kcal protein diets induced the most significant ketoses, which was only partially diminished by choline replacement.Key effects of the 5% kcal protein diet - weight loss, hepatic fat accumulation, and mitochondrial ultrastructural disarray and bioenergetic dysfunction - were mitigated by choline repletion.These studies indicate that synergistic effects of protein restriction and choline deficiency influence integrated metabolism and hepatic pathology in mice when nutritional fat content is very high, and support the consideration of dietary choline content in ketogenic diet studies in rodents to limit hepatic mitochondrial dysfunction and fat accumulation.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Center for Cardiovascular Research, Washington University, St. Louis, Missouri, USA.

ABSTRACT
Though widely employed for clinical intervention in obesity, metabolic syndrome, seizure disorders and other neurodegenerative diseases, the mechanisms through which low carbohydrate ketogenic diets exert their ameliorative effects still remain to be elucidated. Rodent models have been used to identify the metabolic and physiologic alterations provoked by ketogenic diets. A commonly used rodent ketogenic diet (Bio-Serv F3666) that is very high in fat (~94% kcal), very low in carbohydrate (~1% kcal), low in protein (~5% kcal), and choline restricted (~300 mg/kg) provokes robust ketosis and weight loss in mice, but through unknown mechanisms, also causes significant hepatic steatosis, inflammation, and cellular injury. To understand the independent and synergistic roles of protein restriction and choline deficiency on the pleiotropic effects of rodent ketogenic diets, we studied four custom diets that differ only in protein (5% kcal vs. 10% kcal) and choline contents (300 mg/kg vs. 5 g/kg). C57BL/6J mice maintained on the two 5% kcal protein diets induced the most significant ketoses, which was only partially diminished by choline replacement. Choline restriction in the setting of 10% kcal protein also caused moderate ketosis and hepatic fat accumulation, which were again attenuated when choline was replete. Key effects of the 5% kcal protein diet - weight loss, hepatic fat accumulation, and mitochondrial ultrastructural disarray and bioenergetic dysfunction - were mitigated by choline repletion. These studies indicate that synergistic effects of protein restriction and choline deficiency influence integrated metabolism and hepatic pathology in mice when nutritional fat content is very high, and support the consideration of dietary choline content in ketogenic diet studies in rodents to limit hepatic mitochondrial dysfunction and fat accumulation.

Show MeSH
Related in: MedlinePlus