Manifestations of fasting-induced fatty liver and rapid recovery from steatosis in voles fed lard or flaxseed oil lipids

Protective Effect of α-Linolenic Acid on Non-Alcoholic Hepatic Steatosis and Interleukin-6 and -10 in Wistar Rats

Consumption of omega-3 (n-3) polyunsaturated fatty acids (PUFA) is related to improvement in the inflammatory response associated with decreases in metabolic disorders of obesity, such as low-grade inflammation and hepatic steatosis. Linseed (Linum usitatissimum) oil is a primary source of n-3 fatty acids (FAs) of plant origin, particularly α-linolenic acid, and provides an alternative for the ingestion of n-3 PUFA by persons allergic to, or wishing to avoid, animal sources. In our study, we evaluated the effect of the consumption of different lipidic sources on metabolic and inflammatory parameters in Wistar rats. We split 56 male rats into four groups that were fed for 60 days with the following diets: sesame oil, (SO, Sesamum indicum), linseed oil (LO), SO + LO (SLO), and a control group (CG) fed with animal fat. Our results reveal that the use of LO or SLO produced improvements in the hepatic tissue, such as lower values of aspartate aminotransferase, liver weight, and hepatic steatosis. LO and SLO reduced the weight of visceral fats, weight gain, and mediated the inflammation through a decrease in interleukin (IL)-6 and increase in IL-10. Though we did not detect any significant differences in the intestine histology and the purinergic system enzymes, the consumption of α-linolenic acid appears to contribute to the inflammatory and hepatic modulation of animals compared with a diet rich in saturated FAs and or unbalanced in n-6/n-3 PUFAs, inferring possible use in treatment of metabolic disorders associated with obesity and cardiovascular diseases.

Daily Fasting Improves Health and Survival in Male Mice Independent of Diet Composition and Calories

The importance of dietary composition and feeding patterns in aging remains largely unexplored, but was implicated recently in two prominent nonhuman primate studies. Here, we directly compare in mice the two diets used in the primate studies focusing on three paradigms: ad libitum (AL), 30% calorie restriction (CR), and single-meal feeding (MF), which accounts for differences in energy density and caloric intake consumed by the AL mice. MF and CR regimes enhanced longevity regardless of diet composition, which alone had no significant impact within feeding regimens. Like CR animals, MF mice ate quickly, imposing periods of extended daily fasting on themselves that produced significant improvements in morbidity and mortality compared with AL. These health and survival benefits conferred by periods of extended daily fasting, independent of dietary composition, have major implications for human health and clinical applicability.

Free fatty acids profile among lean, overweight and obese non-alcoholic fatty liver disease patients: a case - control study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) given its association with obesity and diabetes may perhaps exert distinct free fatty acids (FFA) pattern, but the understanding of this phenomenon is limited. To this effect, we evaluated FFA profiles among healthy subjects and NAFLD patients stratified by body weight, to identify FFA valuable for early diagnosis of NAFLD.

METHODS

Serum FFA profiles of healthy and NAFLD (lean, overweight and obese) subjects was determined using gas chromatography-mass spectrometry (GC-MS) and distinctions in FFA patterns were evaluated using one-way ANOVA while Receiver operating characteristics (ROC) and logistic regression models were used to explore FFA significant for diagnosing NAFLD.

RESULTS

NAFLD patients presented significantly higher (P < 0.05) serum FFA profiles compared to healthy controls (HC). While total FFA profiles were insignificantly different between lean (2093.33 ± 558.11 μg/ml) and overweight (2420.81 ± 555.18 μg/ml) NAFLD patients, obese NAFLD (2739.01 ± 810.35 μg/ml) presented most significantly elevated (P < 0.05) total FFA profiles compared with HC. Of the four FFA; myristic acid (14:0), palmitoleic acid (16:1), γ-linolenic acid (γ-18:3) and cis-7,10,13,16,19-docosapentaenoic acid (22:5), selected in ROC analysis given their high Youden's index and AUC, only 14:0; 5.58(1.37, 22.76) and 16:1; 4.36(1.34, 14.13) had statistical significant odd ratios.

CONCLUSION

Our findings suggest 14:0 and 16:1 are promising for early diagnosis of NAFLD.

De novo lipogenesis is suppressed during fasting but upregulated at population decline in cyclic voles

Arvicolines are susceptible to the development of fatty liver during short-term fasting. We examined the potential role of de novo lipogenesis (DNL) (i) in the development of fasting-induced fatty liver and (ii) during a population cycle by measuring the mRNA expression of acetyl-CoA carboxylase-1 (ACC1) and fatty acid synthase (FAS). Laboratory voles (Microtus oeconomus and Microtus arvalis) were fed or fasted for 12 or 18 h and their liver mRNA levels were determined. Both species showed decreased mRNA expression of ACC1 and FAS during fasting. This suggests that DNL does not participate in the development of fatty liver in voles, different from human non-alcoholic fatty liver disease. In wild bank voles (Myodes glareolus), the mRNA levels of the genes of interest were higher during the population decline compared to the increase phase. In conclusion, DNL was suppressed during acute fasting but upregulated during a long-term population decline-a period of purported scarcity of high-quality food.

The expression characteristics of mt-ND2 gene in chicken

Subunit 2 of NADH dehydrogenase (ND2) is encoded by the mt-ND2 gene and plays a critical role in controlling the production of the mitochondrial reactive oxygen species. Our study focused on exploring the mt-ND2 tissue expression patterns and the effects of energy restriction and dietary fat (linseed oil, corn oil, sesame oil or lard) level (2.5% and 5%) on its expression in chicken. The results showed that mt-ND2 gene was expressed in the 15 tissues of hybrid chickens with the highest level in heart and lowest level in pancreas tissue; 30% energy restriction did not significantly affect mt-ND2 mRNA level in chicken liver tissue. Both the mt-ND2 mRNA levels in chicken pectoralis (p < 0.05) and hepatic tissues (p < 0.05) at 42 d-old were affected by the type of dietary fats in 5% level, while not in abdominal fat tissues. The expression of mt-ND2 in hepatic tissues was down-regulated with chicken age (p < 0.01). The interactive effect of dietary fat types with chicken age (p < 0.05) was significant on mt-ND2 mRNA level. The study demonstrated that mt-ND2 gene was extensively expressed in tissues, and the expression was affected by dietary fat types and chicken age.

Physiological condition of bank voles (Myodes glareolus) during the increase and decline phases of the population cycle

The dynamics of animal populations are greatly influenced by interactions with their natural enemies and food resources. However, quantifying the relative effects of these factors on demographic rates remains a perpetual challenge for animal population ecology. Food scarcity is assumed to limit the growth and to initiate the decline of cyclic herbivore populations, but this has not been verified with physiological health indices. We hypothesized that individuals in declining populations would exhibit signs of malnutrition-induced deterioration of physiological condition. We evaluated the association of body condition with population cycle phase in bank voles (Myodes glareolus) during the increase and decline phases of a population cycle. The bank voles had lower body masses, condition indices and absolute masses of particular organs during the decline. Simultaneously, they had lower femoral masses, mineral contents and densities. Hemoglobin and hematocrit values and several parameters known to respond to food deprivation were unaffected by the population phase. There were no signs of lymphopenia, eosinophilia, granulocytosis or monocytosis. Erythrocyte counts were higher and plasma total protein levels and tissue proportions of essential polyunsaturated fatty acids lower in the population decline. Ectoparasite load was lower and adrenal gland masses or catecholamine concentrations did not suggest higher stress levels. Food availability seems to limit the size of voles during the decline but they can adapt to the prevailing conditions without clear deleterious health effects. This highlights the importance of quantifying individual health state when evaluating the effects of complex trophic interactions on the dynamics of wild animal populations.

Evidence of endoplasmic reticulum stress and liver inflammation in the American mink Neovison vison with benign hepatic steatosis

We investigated the presence of inflammatory signs in the progression of fatty liver disease induced by fasting. Sixty standard black American mink (Neovison vison) were fasted for 0, 1, 3, 5, or 7 days and one group for 7 days followed by re-feeding for 28 days. Liver sections were evaluated histologically and liver mRNA levels indicating endoplasmic reticulum (ER) stress, adipogenic transformation, and inflammation were assessed by quantitative real-time PCR. After 3 days of fasting, the mink had developed moderate liver steatosis. Increased hyaluronan reactivity in lymphocytic foci but no Mallory-Denk bodies were seen in livers of the mink fasted for 5-7 days. Up-regulation of glucose-regulated protein, 78 kDa was observed on day 7 indicating ER stress, especially in the females. Liver lipoprotein lipase and monocyte chemoattractant protein 1 mRNA levels increased in response to 5-7 days of food deprivation, while tumor necrosis factor α (TNF-α) was the highest in the mink fasted for 5 days. The expression of the genes of interest, except for TNF-α, correlated with each other and with the liver fat content. The mRNA levels were found to change more rapidly below n-3/n-6 polyunsaturated fatty acid ratio threshold of 0.15. Following re-feeding, hepatocyte morphology and mRNA abundance returned to pre-fasting levels. Within the studied timeframe, evidence for ER stress, adipogenic transformation, and liver inflammation suggested incipient transition from steatosis to steatohepatitis with potential for development of more severe liver disease. This may present a possibility to influence disease progression before histologically observable steatohepatitis.