Lack of gut microbiome recovery with spinal cord injury rehabilitation

Spinal cord injury (SCI) is a devastating event that significantly changes daily function and quality of life and is linked to bowel and bladder dysfunction and frequent antibiotic treatment. We aimed to study the composition of the gut microbiome in individuals with SCI during the initial sub-acute rehabilitation process and during the chronic phase of the injury. This study included 100 fecal samples from 63 participants (Median age 40 years, 94% males): 13 cases with SCI in the sub-acute phase with 50 longitudinal samples, 18 cases with chronic SCI, and 32 age and gender-matched controls. We show, using complementary methods, that the time from the injury was a dominant factor linked with gut microbiome composition. Surprisingly, we demonstrated a lack of gut microbial recovery during rehabilitation during the sub-acute phase, with further deviation from the non-SCI control group in the chronic ambulatory SCI group. To generalize the results, we were able to show significant similarity of the signal when comparing to a previous cohort with SCI, to subjects from the American Gut Project who reported low physical activity, and to subjects from another population-based cohort who reported less normal stool consistency. Restoration of the microbiome composition may be another desirable measure for SCI recovery in the future, but further research is needed to test whether such restoration is associated with improved neurological outcomes and quality of life.

Effects of high oleic acid peanuts on mice's liver and adipose tissue metabolic parameters and gut microbiota composition

This study aimed to investigate the effects of two types of peanuts, regular Hanoch (HN) and a new high-oleic cultivar., Hanoch-Oleic (HO), on metabolic parameters and gut microbiota composition. Male C57BL/6 mice were fed with a normal diet (ND) or ND supplemented with HN (NDh) or HO (NDo). Following 18 weeks of diet regimen, the NDo group exhibited reduced body weight and peri-gonadal adipose-to-body weight ratio, paralleled to lesser food consumption. Although blood levels of total cholesterol, HDL-cholesterol, free fatty acids, and liver enzyme levels did not differ between groups, decreased insulin sensitivity was found in the NDh group. Within adipose tissue, the expression of lipolytic and lipogenic enzymes was higher, while those related to lipid oxidation were lower in the NDh group compared to the NDo group. Additionally, HO peanuts consumption promoted the establishment of a healthy microbiota, with an enhanced abundance of Bifidobacterium, Lactobacillus, and Coprococcus genera. In conclusion, the inclusion of the HO peanut cultivar., rather than the conventional peanut cultivar., in a balanced diet was related to better metabolic outcomes and was linked to a favorable microbiota profile.

Chiliadenus iphionoides Reduces Body Weight and Improves Parameters Related to Hepatic Lipid and Glucose Metabolism in a High-Fat-Diet-Induced Mice Model of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has become an epidemic with increasing prevalence. Limited treatment options and poor adherence emphasize the urgent need for novel therapies for the treatment and/or prevention of NAFLD. Bioactive natural compounds found in medicinal plants are promising as novel therapeutic agents for NAFLD. Chiliadenus iphionoides, a medicinal plant with several health-promoting properties, is an encouraging candidate. The current study aimed to elucidate the metabolic effects of C. iphionoides consumption in a high-fat-diet (HFD)-induced model of NAFLD. Male C57BL/6J mice (n = 40, 7–8-week-old) were fed a HFD (60% fat) with/without 0.5 or 2.5 gr C. iphionoides for fifteen weeks. Diet supplementation with C. iphionoides significantly ameliorated HFD-induced weight gain. Likewise, liver and adipose tissue weights were profoundly lower in the C. iphionoides-fed groups. Reduced liver steatosis in those groups was corroborated by histology, plasma liver enzyme levels, and lipid profile, indicating improved liver function and lipid metabolism in addition to enhanced insulin sensitivity. The addition of C. iphionoides to an obesogeneic diet can beneficially alleviate metabolic alterations and may be a practicable strategy for the management of NAFLD.

Metabolic and Microbiome Alterations Following the Enrichment of a High-Fat Diet With High Oleic Acid Peanuts Versus the Traditional Peanuts Cultivar in Mice

A new Israeli-developed peanut cultivar, “Hanoch-Oleic” (HO), uniquely contains enlarged oleic acid contents and was designed to confer additional beneficial effects over the traditional cultivar, “Hanoch” (HN). This work elucidates metabolic changes and microbiota adaptations elicited by HO addition to a high-fat diet (HFD). Male C57BL/6 mice were fed for 18 weeks with a normal diet or a HFD with/without the addition of HN (HFDh) or HO (HFDo). Body-weight did not differ between HFD-fed mice groups, while liver and adipose weight were elevated in the HFDh and HFD groups, respectively. Insulin-sensitivity (IS) was also decreased in these groups, though to a much greater extent in the traditional peanuts-fed group. Modifications in lipids metabolism were evident by the addition of peanuts to a HFD. Liver inflammation seems to return to normal only in HFDh. Peanuts promoted an increase in α-diversity, with HFDo exhibiting changes in the abundance of microbiota that is primarily associated with ameliorated gut health and barrier capacity. In conclusion, the HO cultivar appears to be metabolically superior to the traditional peanut cultivar and was associated with an improved inflammatory state and microbial profile. Nevertheless, IS-negative effects reinforced by peanuts addition, predominantly NH, need to be comprehensively defined.

Broccoli consumption attenuates inflammation and modulates gut microbiome composition and gut integrity-related factors in mice fed with a high-fat high-cholesterol diet

Background: Nonalcoholic fatty-liver disease (NAFLD) is a global health problem associated with gut dysbiosis and intestinal permeability. Broccoli is a natural source of bioactive phytochemicals, characterized by health-promoting properties. Objective: This study evaluated the effect of broccoli florets and stalks on liver fat accumulation, inflammation, gut microbiome, and intestinal barrier integrity. Design: Male C57BL/6J mice (n = 32, 8-week-old) were fed with a high-fat high-cholesterol diet (HFCD) with/without 15% broccoli (florets or stalks) for 7 weeks. Liver damage was evaluated by changes in glucose response and histological and biochemical parameters. Protein and gene expressions related to liver inflammation were examined. The effect of broccoli on microbiota population together with genes related to barrier integrity in the gut was investigated. Results: Dietary broccoli improved the glycemic response assessed by oral glucose tolerance test (OGTT). Histological evaluation showed no change in hepatic steatosis. Broccoli consumption also attenuated inflammation as revealed by lower inducible nitric oxide synthase (iNOS) and serum amyloid A1 (SAA1) expression levels in broccoli-supplemented groups. Gut microbiota analysis demonstrated elevated Acidifaciens and reduced Mucispirillum schaedleri abundance in the stalks group, whereas Proteobacteria strains abundance was increased in the florets group. Gut integrity remained unchanged. Conclusion: Broccoli supplementation improves glucose tolerance, attenuates liver inflammation, and alters microbial composition, but does not affect gut integrity. This research provides new evidence on the effects of dietary broccoli under HFCD.

Broccoli Florets Supplementation Improves Insulin Sensitivity and Alters Gut Microbiome Population-A Steatosis Mice Model Induced by High-Fat Diet

Nonalcoholic fatty liver disease (NAFLD) is linked to obesity, type 2 diabetes, hyperlipidemia, and gut dysbiosis. Gut microbiota profoundly affects the host energy homeostasis, which, in turn, is affected by a high-fat diet (HFD) through the liver-gut axis, among others. Broccoli contains beneficial bioactive compounds and may protect against several diseases. This study aimed to determine the effects of broccoli supplementation to an HFD on metabolic parameters and gut microbiome in mice. Male (7–8 weeks old) C57BL/J6 mice were divided into four groups: normal diet (ND), high-fat diet (HFD), high-fat diet+10% broccoli florets (HFD + F), and high-fat diet + 10% broccoli stalks (HFD + S). Liver histology and serum biochemical factors were evaluated. Alterations in protein and gene expression of the key players in lipid and carbohydrate metabolism as well as in gut microbiota alterations were also investigated. Broccoli florets addition to the HFD significantly reduced serum insulin levels, HOMA-IR index, and upregulated adiponectin receptor expression. Conversely, no significant difference was found in the group supplemented with broccoli stalks. Both broccoli stalks and florets did not affect fat accumulation, carbohydrate, or lipid metabolism-related parameters. Modifications in diversity and in microbial structure of proteobacteria strains, Akermansia muciniphila and Mucispirillum schaedleri were observed in the broccoli-supplemented HFD-fed mice. The present study suggests that dietary broccoli alters parameters related to insulin sensitivity and modulates the intestinal environment. More studies are needed to confirm the results of this study and to investigate the mechanisms underlying these beneficial effects.

Dietary broccoli improves markers associated with glucose and lipid metabolism through modulation of gut microbiota in mice

OBJECTIVE

Broccoli is a "functional food" that contains bioactive compounds and phytochemicals that have beneficial health-promoting effects. This study aimed at investigating the effects of broccoli consumption on lipid and glucose metabolism and gut microbiota.

METHODS

Male C57BL/6J mice (7-8 wk old) were fed ad libitum with a normal diet supplemented with or without 10% (w/w) broccoli florets or broccoli stalks. Oral glucose tolerance tests were performed at week 15. After 17 wk, blood and tissues were collected. Serum parameters, histology, gene and protein expression, and intestinal microbiota composition were evaluated.

RESULTS

Stalk supplementation led to reductions in fasting glucose levels, serum insulin, and the homeostasis model assessment-insulin resistance (HOMA-IR) index. Liver enzymes improved in both experimental groups, and broccoli florets decreased total triacylglycerols. The stalks group had elevated fatty acid oxidation-related genes and proteins (AMPK, PPARα, and CPT1). Diverse microbiota populations were observed in both broccoli groups. Broccoli stalks were found to be richer in Akkermansia muciniphila, while broccoli florets reduced Mucispirillum schaedleri abundance and increased bacterial richness.

CONCLUSIONS

Long-term whole broccoli supplementation decreased inflammation, improved lipid parameters and insulin sensitivity, and altered the gut microbiome in mice. Our data provide new information regarding the potential benefits of broccoli stalks in metabolic parameters.

Cannabis Extracts Affected Metabolic Syndrome Parameters in Mice Fed High-Fat/Cholesterol Diet

Introduction: Nonalcoholic fatty liver disease (NAFLD) is associated with metabolic syndrome, which often includes obesity, diabetes, and dyslipidemia. Several studies in mice and humans have implicated the involvement of the gut microbiome in NAFLD. While cannabis may potentially be beneficial for treating metabolic disorders such as NAFLD, the effects of cannabis on liver diseases and gut microbiota profile are yet to be addressed. In this study, we evaluated the therapeutic effects of cannabis strains with different cannabinoid profiles on NAFLD progression. Materials and Methods: NAFLD was induced by feeding mice a high-fat/cholesterol diet (HFCD) for 6 weeks. During this period, cannabis extracts were administrated orally at a concentration of 5 mg/kg every 3 days. Profile of lipids, liver enzymes, glucose tolerance, and gene expression related to carbohydrate lipid metabolism and liver inflammation were analyzed. The effect of cannabis strains on microbiota composition in the gut was evaluated. Results: A cannabidiol (CBD)-rich extract produced an increase in inflammatory related gene expression and a less diverse microbiota profile, associated with increased fasting glucose levels in HFCD-fed mice. In contrast, mice receiving a tetrahydrocannabinol (THC)-rich extract exhibited moderate weight gain, improved glucose response curves, and a decrease in liver enzymes. Conclusions: The results of this study indicate that the administration of cannabis containing elevated levels of THC may help ameliorate symptoms of NAFLD, whereas administration of CBD-rich cannabis extracts may cause a proinflammatory effect in the liver, linked with an unfavorable change in the microbiota profile. Our preliminary data suggest that these effects are mediated by mechanisms other than increased expression of the endocannabinoid receptors cannabinoid receptor 1 (CB1) and CB2.

High oleic peanuts improve parameters leading to fatty liver development and change the microbiota in mice intestine

Background

Oleic-acid consumption can possibly prevent or delay metabolic diseases. In Israel, a Virginia-type peanut cultivar with a high content of oleic acid has been developed.

Objective

This study examined the effect of consuming high oleic peanuts (D7) on the development of fatty liver compared to the standard HN strain.

Design

The two peanut cultivars were added to normal diet (ND) and high-fat (HF) mouse diet. Male C57BL/6 mice were fed for 8 and 10 weeks on a 4% D7, 4% HN, or control diet. At the end of the experiments, blood and tissues were collected. Triglyceride, lipid levels, histology, and protein expression were examined. The diets’ effects on intestinal microbiota were also evaluated.

Results

Both D7 and HFD7 led to a reduction in plasma triglycerides. Lipids, triglycerides, and free fatty acids in the liver were low in diets containing D7. Additionally, CD36 expression decreased in the D7 group. Consumption of D7 led to higher Prevotella levels, and consumption of ND that contained HN or D7 led to a lower Firmicutes/Bacteroidetes ratio.

Conclusion

These findings suggest that consumption of peanuts high in oleic acid (D7) may have the potential to delay primary fatty liver symptoms.

Effect of dietary oils from various sources on carbohydrate and fat metabolism in mice

Background

Dietary oils differ in their fatty acid composition and the presence of additional microcomponents (antioxidants, etc.). These differences are thought to invoke different biochemical pathways, thus affecting fats and carbohydrates metabolism differently. Olive oil (OO) and soybean oil (SO) are common vegetable oils in the local cuisine. Peanuts oils of local varieties are viewed as potential sources of dietary vegetable oils, especially in the food industry.

Objective

We examined the effect of four different dietary vegetable oils on carbohydrate and lipid metabolism in mice. The selected oils were OO, high in oleic acid, extracted from cultivated high oleic acid peanut (C-PO), regular peanut oil (PO), and SO.

Design

In this study, 32 male C57BL/6J mice were randomly divided into four groups (n = 8 in each group) and were fed with four different diets enriched with 4% (w/w) dietary vegetable oils (OO, C-PO, PO, or SO). After 10 weeks, the mice were sacrificed. Western blot was used to examine proteins such as phospho-AMP-activated protein kinase (p-AMPK), ace-tyl-CoA carboxylase (ACC), cluster of differentiation 36 (CD36), and Sirtuin 1 (SIRT1), whereas real-time polymerase chain reaction (PCR) was used to examine the expression of sterol regulatory element-binding protein-1c (SREBP-1C), fatty acid synthase (FAS), glucose-6-phosphatase (G6Pase), and CD36 transcripts.

Results

In mice-fed SO, lipid accumulation was predominately in adipose tissue, accompanied a tendency decrease in insulin sensitivity. Mice-fed OO had lower plasma triglycerides (TG) and increased hepatic CD36 gene expression. The C-PO group presented lower messenger RNA (mRNA) levels in the liver for all examined genes: SREBP-1c, FAS, G6Pase, and CD36. There were no significant differences in weight gain, plasma cholesterol and high-density lipoprotein (HDL) cholesterol levels, hepatic ACC, SIRT1, AMPK, and CD36 protein levels or in liver function among the diets.

Discussion

It seems that as long as fat is consumed in moderation, oil types may play a lesser role in the metabolism of healthy individuals.

Conclusion

This finding has the potential to increase flexibility in choosing oil types for consumption.

Utilization of a Deep Learning Algorithm for Microscope-Based Fatty Vacuole Quantification in a Fatty Liver Model in Mice

Quantification of fatty vacuoles in the liver, with differentiation from lumina of liver blood vessels and bile ducts, is an example where the traditional semiquantitative pathology assessment can be enhanced with artificial intelligence (AI) algorithms. Using glass slides of mice liver as a model for nonalcoholic fatty liver disease, a deep learning AI algorithm was developed. This algorithm uses a segmentation framework for vacuole quantification and can be deployed to analyze live histopathology fields during the microscope-based pathology assessment. We compared the manual semiquantitative microscope-based assessment with the quantitative output of the deep learning algorithm. The deep learning algorithm was able to recognize and quantify the percent of fatty vacuoles, exhibiting a strong and significant correlation (r = 0.87, P < .001) between the semiquantitative and quantitative assessment methods. The use of deep learning algorithms for difficult quantifications within the microscope-based pathology assessment can help improve outputs of toxicologic pathology workflows.

Utilization of a Deep Learning Algorithm for Microscope-Based Fatty Vacuole Quantification in a Fatty Liver Model in Mice

Quantification of fatty vacuoles in the liver, with differentiation from lumina of liver blood vessels and bile ducts, is an example where the traditional semiquantitative pathology assessment can be enhanced with artificial intelligence (AI) algorithms. Using glass slides of mice liver as a model for nonalcoholic fatty liver disease, a deep learning AI algorithm was developed. This algorithm uses a segmentation framework for vacuole quantification and can be deployed to analyze live histopathology fields during the microscope-based pathology assessment. We compared the manual semiquantitative microscope-based assessment with the quantitative output of the deep learning algorithm. The deep learning algorithm was able to recognize and quantify the percent of fatty vacuoles, exhibiting a strong and significant correlation (r = 0.87, P < .001) between the semiquantitative and quantitative assessment methods. The use of deep learning algorithms for difficult quantifications within the microscope-based pathology assessment can help improve outputs of toxicologic pathology workflows.

The effect of a low-carbohydrate high-fat diet and ethnicity on daily glucose profile in type 2 diabetes determined by continuous glucose monitoring

BACKGROUND AND AIMS

Nutrition is an integral part of type 2 diabetes (T2DM) treatment, but the optimal macronutrient composition is still debated and previous studies have not addressed the role of ethnicity in dietary response. The current study aims were to compare the effect of short-term glycemic response to low-carbohydrate high-fat (LC-HF) diet vs. high-carbohydrate low-fat (HC-LF) diet using continuous glucose monitoring (CGM) and to evaluate the response of individuals with T2DM of Yemenite (Y-DM) and non-Yemenite origin (NY-DM).

METHODS

Twenty T2DM males, ten Y-DM and ten NY-DM underwent meal tolerance test and indexes of insulin resistance and secretion were calculated. Subsequently, patients were connected to CGM to assess daily glycemic control and glucose variability in response to isocaloric HC-LF or LC-HF diet, receiving each diet for 2 days by providing prepared meals. Daily glucose levels, area under the glucose curve (G-AUC) and parameters of glucose variability [standard deviation (SD), mean amplitude of glycemic excursions (MAGE) and mean absolute glucose (MAG)] were evaluated.

RESULTS

The LC-HF resulted in a significantly lower G-AUC (p < 0.001) and in lower variability parameters (p < 0.001) vs. the HC-LF diet. However, Y-DM showed less reduction in glucose variability indices upon diet-switching vs. NY-DM; MAGE decreased, respectively, by 69% vs. 89%, p = 0.043 and MAG by 34% vs. 45%, p = 0.007 in Y-DM compared to NY-DM.

CONCLUSIONS

These results suggest that LC-HF diet is effective in reducing glycemic fluctuation in T2DM and that ethnicity may have a role in the response to dietary regime.

Fenugreek galactomannan and citrus pectin improve several parameters associated with glucose metabolism and modulate gut microbiota in mice

OBJECTIVE

Galactomannans derived from fenugreek confer known health benefits; however, there is little information regarding health benefits of citrus pectin (CP) and its association with gut microbiome metabolites. The aim of this study was to examine links between galactomannan and CP consumption, microbiota development, and glucose metabolism.

DESIGN

Male C57 BL/6 J mice ages 7 to 8 wk were fed ad libitum with a normal diet or one supplemented with 15% of either galactomannan or CP. At 3 wk, an oral glucose tolerance test was performed. Animals were sacrificed at 4 wk and relevant organs were harvested.

RESULTS

Fiber enrichment led to reductions in weight gain, fasting glucose levels, and total serum cholesterol (P < 0.05). Compared with mice fed the normal diet, microbiota populations were altered in both fiber groups and were found to be richer in Bacteroidetes rather than Firmicutes (P < 0.05). The modification was significantly greater in galactomannan-fed than in CP-fed mice (P < 0.0001). Also, enhanced levels of the short-chain fatty acid (SCFA) propionate were found in the cecal contents of CP-fed animals (P < 0.05). Protein expression levels of monocarboxylate transporter 1, which may promote transport of SCFA, were measured in the large intestines after fiber consumption. Enhanced adenosine monophosphate-activated protein kinase (AMPK) activation was observed in livers of galactomannan-fed mice (P < 0.05).

CONCLUSION

Consumption of diets containing soluble fibers, as used in this study, resulted in gut microbiota comprising a healthier flora, and led to positive effects on weight, glycemic control, and liver β oxidation via AMPK.

Non-alcoholic fatty liver disease, to struggle with the strangle: Oxygen availability in fatty livers

Nonalcoholic fatty liver diseases (NAFLD) is one of the most common chronic liver disease in Western countries. Oxygen is a central component of the cellular microenvironment, which participate in the regulation of cell survival, differentiation, functions and energy metabolism. Accordingly, sufficient oxygen supply is an important factor for tissue durability, mainly in highly metabolic tissues, such as the liver. Accumulating evidence from the past few decades provides strong support for the existence of interruptions in oxygen availability in fatty livers. This outcome may be the consequence of both, impaired systemic microcirculation and cellular membrane modifications which occur under steatotic conditions. This review summarizes current knowledge regarding the main factors which can affect oxygen supply in fatty liver.

Prolonged feeding with green tea polyphenols exacerbates cholesterol-induced fatty liver disease in mice

SCOPE

This study investigated the potential deleterious impact of dietary supplementation with green tea extract (GTE) on the progression of fatty liver disease, in a mouse model of cholesterol-induced steatohepatitis that represents chronic liver injury.

METHODS AND RESULTS

Male C57BL mice (n = 32, 8-wk-old) were fed for 6 wk with one of the following diets: normal control diet (ND, Con), Con + 1% w/w polyphenols from GTE (Con + GTE); high cholesterol diet, Con + 1% cholesterol + 0.5% cholate w/w (HCD); HCD + 1% green tea polyphenols w/w (HCD + GTE). Hepatic steatosis, oxidative, and inflammatory markers and bile acid synthesis pathways were measured. HCD supplementation resulted in hepatic steatosis and liver damage. In animals supplemented with the HCD + GTE an exacerbated hepatic steatosis, oxidative stress, and inflammatory response were observed compared to HCD supplemented animals. HCD + GTE supplementation elevated blood levels of liver enzymes and serum bile acids compared HCD-treated animals. HCD + GTE supplementation altered bile acid synthesis in the cholesterol clearance pathway, inducing a shift from the classically regulated CYP7A1 pathway to the alternative acidic pathway.

CONCLUSION

Prolonged GTE supplementation dramatically increased hepatic oxidative stress, inflammation and liver injury, and altered the bile acid synthesis pathway in mice fed a HCD.

Early beta-cell dysfunction characterizes males with type 2 diabetes of Yemenite origin

AIMS

The aim of the current study was to characterize β-cell function, insulin sensitivity and line of inheritance in patients with recent-onset type 2 diabetes of Yemenite and non-Yemenite Jewish origin.

METHODS

A cohort study including 121 GAD negative diabetic patients, 59 of Yemenite and 62 of non-Yemenite origin, treated by diet ± oral antihyperglycemic monotherapy who underwent 180-min meal tolerance test (MMT). Based on MMT, indexes of insulin resistance and secretion were calculated.

RESULTS

There were no significant differences in age, sex, diabetes duration, BMI, HbA1c and lipid profile. A significant difference was found in family history of diabetes: 63 % of patients of Yemenite origin had maternal inheritance versus 35 % in the non-Yemenite origin (p < 0.001). Both indexes of β-cell function, the insulinogenic and the disposition indexes were significantly lower in patients of Yemenite origin compared with non-Yemenite origin (0.66 ± 0.4 vs. 0.93 ± 0.8, p = 0.04; 2.3 ± 1.8 vs. 3.3 ± 3.3, p = 0.04, respectively) with no difference in insulin sensitivity. When females and males were analyzed separately, the difference in maternal inheritance remained significant in both, but the difference in β-cell function indexes was observed only in males (p = 0.03, p = 0.01, respectively).

CONCLUSIONS

Males with recent-onset diabetes of Yemenite origin have a significant reduction of β-cell function and reduced ability to compensate for insulin resistance compared with diabetic males of non-Yemenite origin. Both males and females of Yemenite origin have a significantly higher maternal inheritance of diabetes. These data suggest different underlying mechanisms leading to early loss of β-cell in diabetic males of Yemenite origin.

Concentrating carbohydrates before sleep improves feeding regulation and metabolic and inflammatory parameters in mice

New evidance highlights the importance of food timing. Recently, we showed that a low-calorie diet with carbohydrates eaten mostly at dinner changed diurnal hormone secretion and led to greater weight loss and improved metabolic status in obese people. Herein, we set out to test whether concentrated-carbohydrates diet (CCD), in which carbohydrates are fed only before sleep, leads to an improved metabolic status in mouse hypothalamus and peripheral tissues. Diet-induced obese mice were given concentrated or distributed carbohydrate diet for 6 weeks. Obese mice fed CCD ate 8.3% less, were 9.3% leaner and had 39.7% less fat mass. Leptin, ghrelin and adiponectin displayed altered secretion. In addition, these mice exhibited an improved biochemical and inflammatory status. In the hypothalamus, anorexigenic signals were up-regulated and orexigenic signals were down-regulated. In peripheral tissues, CCD promoted adiponectin signaling, repressed gluconeogenesis, enhanced lipid oxidation and lowered inflammation, thus ameliorating the major risk factors of obesity.

Glabridin, an isoflavan from licorice root, downregulates iNOS expression and activity under high-glucose stress and inflammation

SCOPE

In females, hyperglycemia abolishes estrogen-vascular protection, leading to inflammation and oxidative stress that are related to diabetes-associated cardiovascular complications. Such knowledge led us to examine the potential of glabridin, as a replacement of estrogen anti-inflammatory activity under high-glucose conditions.

METHODS AND RESULTS

In macrophage-like cells, chronic glucose stress (28 and 44 mM) upregulated inducible nitric oxide synthase (iNOS) mRNA expression by 42 and 189%, respectively. Pretreatment with glabridin, under chronic glucose stress, downregulated the LPS-induced nitric oxide secretion and nitrotyrosine formation, by 39 and 21%, respectively. Pretreatment with estradiol did not prevent the LPS-induced nitrotyrosine formation. Furthermore, glabridin, brought about a decrease in the LPS-induced iNOS mRNA expression by 48%, as compared to cells pretreated with estradiol. Glabridin decreased protein levels of liver iNOS by 69% in adult mouse offspring which developed hyperglycemia after early fetal exposure to a saturated fatty acid-enriched maternal diet. Glabridin also decreased liver nitrotyrosine levels in offspring of regular diet-fed mothers after further receiving high-fat diet.

CONCLUSION

Such results indicate that glabridin retains anti-inflammatory abilities to regulate the synthesis and activity of iNOS under high-glucose levels, implying that a glabridin supplement may serve as an anti-inflammatory agent in diabetes-related vascular dysfunction.

Nutrition targeting by food timing: time-related dietary approaches to combat obesity and metabolic syndrome

Effective nutritional guidelines for reducing abdominal obesity and metabolic syndrome are urgently needed. Over the years, many different dietary regimens have been studied as possible treatment alternatives. The efficacy of low-calorie diets, diets with different proportions of fat, protein, and carbohydrates, traditional healthy eating patterns, and evidence-based dietary approaches were evaluated. Reviewing literature published in the last 5 y reveals that these diets may improve risk factors associated with obesity and metabolic syndrome. However, each diet has limitations ranging from high dropout rates to maintenance difficulties. In addition, most of these dietary regimens have the ability to attenuate some, but not all, of the components involved in this complicated multifactorial condition. Recently, interest has arisen in the time of day foods are consumed (food timing). Studies have examined the implications of eating at the right or wrong time, restricting eating hours, time allocation for meals, and timing of macronutrient consumption during the day. In this paper we review new insights into well-known dietary therapies as well as innovative time-associated dietary approaches for treating obesity and metabolic syndrome. We discuss results from systematic meta-analyses, clinical interventions, and animal models.

The impact of a Web-based app (eBalance) in promoting healthy lifestyles: randomized controlled trial

Background

The use of Web-based apps to promote a healthy lifestyle is increasing, although most of these programs were not assessed using suitable epidemiological methods. We evaluated the effectiveness of a newly developed Web-based app in promoting a healthy lifestyle and educating adults on such lifestyles. We also analyzed predictors for success in acquiring and maintaining a healthy lifestyle.

Objective

Our aim was to compare people receiving a new Web-based app with people who got an introductory lecture alone on healthy lifestyle, weight change, nutritional knowledge, and physical activity, and to identify predictors of success for maintaining a healthy lifestyle.

Methods

Subjects were recruited from the community and were randomized into intervention and control groups. The intervention subjects received access to the app without any face-to-face support; the control subjects continued their standard lifestyle. Measurements were taken by the researcher at baseline and after 14 weeks and included weight and waist circumference. Nutritional knowledge, diet quality, and physical activity duration were obtained using online questionnaires. The new Web-based app was developed based on current US Department of Agriculture and Israel Ministry of Health recommendations for healthy lifestyle. The app provides tools for monitoring diet and physical activity while instructing and encouraging healthy diet and physical activity.

Results

Out of 99 subjects who were randomized into app and control groups, 85 participants (86%) completed the study, 56 in the intervention and 29 in the control group. The mean age was 47.9 (SD 12.3) years, and mean Body Mass Index was 26.2 (SD 3.9). Among the intervention group only, frequency of app use was 2.7 (SD 1.9) days/week. The mean change in physical activity was 63 (SD 20.8) minutes in the app group and -30 (SD 27.5) minutes in the control group (P=.02). The mean weight change was -1.44 (SD 0.4) kg in the app group and -0.128 (SD 0.36) kg in the control group (P=.03). Knowledge score increased significantly in the app group, 76 (SD 7.5) to 79 (SD 8.7) at the end of the study (P=.04) compared with the control group. Diet quality score also increased significantly at the end of the study, from 67 (SD 9.8) to 71 (SD 7.6; P<.001) in contrast to the control group. Success score (represents the success in maintaining healthy lifestyle) was higher among the app group (68%) compared with 36% in the control group (P<.001). The app frequency of use was significantly related to a higher success score (P<.001).

Conclusions

We showed a positive impact of a newly developed Web-based app on lifestyle indicators during an intervention of 14 weeks. These results are promising in the app’s potential to promote a healthy lifestyle, although larger and longer duration studies are needed to achieve more definitive conclusions.

Trial Registration

Clinicaltrial.gov number: NCT01913496; http://www.clinicaltrials.gov/ct2/show/NCT01913496 (Archived by WebCite at http://www.webcitation.org/6WSTUEPuJ).

Mechanism for HIF-1 activation by cholesterol under normoxia: a redox signaling pathway for liver damage

Cholesterol and chronic activation of hypoxia-inducible factor-1 (HIF-1) have been separately implicated in the pathogenesis and progression of liver diseases. In AML12 hepatocytes increased HIF-1α protein accumulation was evident after 2 h of incubation with cholesterol, whereas enhanced HIF-1 transcriptional activity was observed after 6 h. Investigations into the molecular mechanism have shown that cholesterol inhibited HIF-1α degradation. Mitochondrial dysfunction and enhanced mitochondrial reactive oxygen species (ROS) generation were observed in 2-h cholesterol-treated cells along with augmented nitric oxide (NO) levels. Further analysis indicated that HIF-1α stabilization at later time (6h), but not after 2h, of incubation with cholesterol was dependent on NO production. To elucidate the role of mitochondrial dysfunction in HIF-1α stabilization, mitochondrial DNA-depleted hepatocytes were prepared. In these cells the ability of cholesterol to activate the HIF-1 pathway was abolished. Similarly, catalase overexpression also attenuated cholesterol-induced HIF-1α accumulation. These results demonstrate that cholesterol promotes HIF-1 activation in a ROS- and NO-dependent manner. Chronic liver activation of HIF-1 by cholesterol may mediate its deleterious effects in the liver.

Big breakfast rich in protein and fat improves glycemic control in type 2 diabetics

OBJECTIVE

Our goal was to evaluate the effect of breakfast size and composition on body weight, glycemic control, and metabolic markers in adults with type 2 diabetes mellitus (T2DM).

METHODS

59 overweight/obese adults with T2DM were randomized to one of two isocaloric diabetic diets for 3 months; big breakfast (BB), breakfast was rich in fat and protein and provided 33% of total daily energy or small breakfast (SB), breakfast was rich in carbohydrates and provided 12.5% of total daily energy.

RESULTS

Although body weight was reduced similarly in both groups, the BB group showed greater HbA1c and systolic blood pressure reductions (HbA1c: -4.62% vs. -1.46%, p = 0.047; SBP -9.58 vs. -2.43 mmHg; p = 0.04). T2DM medication dose was reduced in a greater proportion of the BB participants (31% vs. 0%; p = 0.002) while in the SB, a greater proportion of participants had a dose increases (16.7% vs. 3.4%; p = 0.002). Hunger scores were lower in the BB group and greater improvements in fasting glucose were observed in the BB group.

CONCLUSIONS

A simple dietary manipulation enriching breakfast with energy as protein and fat appears to confer metabolic benefits and might be a useful alternative for the management of T2DM.

A novel antihypoglycemic role of inducible nitric oxide synthase in liver inflammatory response induced by dietary cholesterol and endotoxemia

AIMS

The current study aim was to elucidate the antihypoglycemic role and mechanism of inducible nitric oxide synthase (iNOS) under inflammatory stress.

METHODS

Liver inflammatory stress was induced in wild-type (WT) and iNOS-knockout (iNOS(-/-)) mice by lipopolysaccharide (LPS) (5 mg/kg) with and without the background of nonalcoholic steatohepatitis (NASH)-Induced by high cholesterol diet (HCD, 6 weeks).

RESULTS

HCD led to steatohepatitis in WT and iNOS(-/-) mice. LPS administration caused marked liver inflammatory damage only in cholesterol-fed mice, which was further exacerbated in the absence of iNOS. Glucose homeostasis was significantly impaired and included fatal hypoglycemia and inhibition of glycogen decomposition. In iNOS(-/-) hypoxia-inducible factor-1 (HIF1), signaling was impaired compared to control WT. Using hydrodynamic gene transfer method HIF1α was expressed in the livers of iNOS(-/-) mice, and significantly ameliorated cholesterol and LPS-induced liver damage. WT mice overexpressing HIF1α exhibited higher blood glucose levels and lower glycogen contents after LPS injection. Conversely, induction of HIF1α was not effective in preventing LPS-induced glucose lowering effect in iNOS(-/-) mice. The critical role of NO signaling in hepatocytes glucose output mediated by HIF1 pathway was also confirmed in vitro. Results also demonstrated increased oxidative stress and reduced heme oxygenase-1 mRNA in the livers of iNOS(-/-) mice. Furthermore, the amounts of plasma tumor necrosis factor-α (TNFα) and intrahepatic TNFα mRNA were significantly elevated in the absence of iNOS.

INNOVATION AND CONCLUSION

These data highlight the essential role of iNOS in the glycemic response to LPS in NASH conditions and argues for the beneficial effects of iNOS.

Changes in daily leptin, ghrelin and adiponectin profiles following a diet with carbohydrates eaten at dinner in obese subjects

BACKGROUND AND AIMS

Our recently published randomised clinical trial evaluated the effect of a low-calorie diet with carbohydrates eaten at dinner. This dietary pattern led to lower hunger scores, and better anthropometric, biochemical and inflammatory outcomes compared to a standard low-calorie diet. In the same study, changes in diurnal secretion patterns of leptin, ghrelin and adiponectin were investigated.

METHODS AND RESULTS

Seventy-eight police officers (body mass index (BMI) > 30) were randomly allocated to experimental (carbohydrates at dinner) or control weight loss diets for 6 months. Sixty-three subjects finished the programme. On days 0, 7, 90 and 180 blood samples and hunger scores were collected every 4 h from 8:00 to 20:00. Hormonal profiles were available for 39. The dietary manipulation led to changes in daylight hormonal profiles in the experimental group. Leptin's secretion curve became convex, with a nadir later in the day (significant difference compared to baseline at morning and evening, p = 0.023, p = 0.021, respectively). Ghrelin's secretion curve became concave, peaking only in the evening hours. Adiponectin's curve was elevated only after the experimental diet (significant difference compared to baseline at afternoon, p = 0.044).

CONCLUSIONS

We propose that a low-calorie diet with carbohydrates eaten at dinner can modulate daytime hormonal profiles. Taken together with our earlier results, we believe this diet regime may prevent mid-day hunger, better support weight loss and improve metabolic outcomes compared to conventional weight loss diets. The trial is registered at controlled-trials.com, ISRCTN37829376, December 2009.

Dexamethasone induces high-amplitude rhythms in preadipocytes, but hinders circadian expression in differentiated adipocytes

Glucocorticoids induce circadian gene expression in cultured cells and change the phase of circadian gene expression in vivo. In addition, glucocorticoids induce differentiation of preadipocyte to adipocytes. We set out to test the effect of dexamethasone, a glucocorticoid receptor agonist, on circadian rhythms in 3T3-L1 differentiated adipocytes. Our results show that differentiated adipocytes exhibit robust circadian rhythms without dexamethasone. Dexamethasone induces phase changes and increases the amplitude of circadian gene expression in nondifferentiated 3T3-L1 preadipocytes. However, dexamethasone had an opposite effect on differentiated adipocytes, leading to low-amplitude circadian expression. In conclusion, although glucocorticoids reset circadian rhythms, once rhythms are reset, glucocorticoid administration hinders circadian expression.

Nitric oxide, can it be only good? Increasing the antioxidant properties of nitric oxide in hepatocytes by YC-1 compound

The aim of the study was to evaluate the effect of Nitric oxide (NO) on redox changes and fat accumulation in hepatocytes. AML-12 hepatocytes were exposed to the NO donor Diethylenetriamine-NONOate (DETA-NO). DETA-NO led to a dose- and time-dependent increase in lipid accumulation in the cells, measured by Nile red fluorescence. Exposure of the cells to 1mM DETA-NO for 24h increased reactive oxygen species production, mainly peroxides. At the same time, NO induced elevation of reduced glutathione (GSH) and a mild activation of the antioxidant transcription factors Hypoxia-inducible factor 1α (HIF1α) and NF-E2 related factor 2 (Nrf-2). We used 100 μM YC-1 to inhibit HIF1α activity and induce activation of soluble Guanylate Cyclase (sGC). YC-1 alone did not affect fat accumulation, and only moderately increased the expression of Nrf-2-targeted genes Heme oxygenase 1 (Hmox1), NAD(P)H dehydrogenase (quinone 1) (Nqo1) and Glutathione S-transferase α1 (Gstα1). However, YC-1 abolished the negative effect of NO on fat accumulation when administered together. Strikingly, YC-1 potentiated the effect of NO on Nrf-2 activation, thus increasing dramatically the antioxidant properties of NO. Moreover, YC-1 intensified the effect of NO on the expression of peroxisome-proliferator-activated receptor-gamma co-activator 1α (PGC1α) and mitochondrial biogenesis markers. This study suggests that YC-1 may shift the deleterious effects of NO into the beneficial ones, and may improve the antioxidant properties of NO.

Metformin affects the circadian clock and metabolic rhythms in a tissue-specific manner

Metformin is a commonly-used treatment for type 2 diabetes, whose mechanism of action has been linked, in part, to activation of AMP-activated protein kinase (AMPK). However, little is known regarding its effect on circadian rhythms. Our aim was to evaluate the effect of metformin administration on metabolism, locomotor activity and circadian rhythms. We tested the effect of metformin treatment in the liver and muscle of young lean, healthy mice, as obesity and diabetes disrupt circadian rhythms. Metformin led to increased leptin and decreased glucagon levels. The effect of metformin on liver and muscle metabolism was similar leading to AMPK activation either by liver kinase B1 (LKB1) and/or other kinases in the muscle. AMPK activation resulted in the inhibition of acetyl CoA carboxylase (ACC), the rate limiting enzyme in fatty acid synthesis. Metformin also led to the activation of liver casein kinase I α (CKIα) and muscle CKIε, known modulators of the positive loop of the circadian clock. This effect was mainly of phase advances in the liver and phase delays in the muscle in clock and metabolic genes and/or protein expression. In conclusion, our results demonstrate the differential effects of metformin in the liver and muscle and the critical role the circadian clock has in orchestrating metabolic processes.

Fatty acids-stress attenuates gluconeogenesis induction and glucose production in primary hepatocytes

BACKGROUND

Hepatic gluconeogenesis tightly controls blood glucose levels in healthy individuals, yet disorders of fatty acids (FAs) oxidation are characterized by hypoglycemia. We studied the ability of free-FAs to directly inhibit gluconeogenesis, as a novel mechanism that elucidates the hypoglycemic effect of FAs oxidation defects.

METHODS

Primary rat hepatocytes were pre-treated with FAs prior to gluconeogenic stimuli with glucagon or dexamethasone and cAMP.

RESULTS

Pre-treatment with 1 mM FAs (mixture of 2:1 oleate:palmitate) for 1 hour prior to gluconeogenic induction, significantly decreases the induced expression of the gluconeogenic genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6pase) as well as the induced glucose production by the cells. The inhibitory effect of FAs upon gluconeogenesis is abolished when pre-treatment is elongated to 18 hours, allowing clearance of FAs into triglycerides by the cells. Replacement of palmitate with the non-metabolic fatty acid 2-bromopalmitate inhibits esterification of FAs into triglycerides. Accordingly, the increased exposure to unesterified-FAs allows their inhibitory effect to be extended even when pre-treatment is elongated to 18 hours. Similar changes were caused by FAs to the induction of peroxisome-proliferator-activated receptor-γ coactivator 1α (PGC1α) expression, indicating this transcriptional coactivator as the mediating link of the effect. This inhibitory effect of FAs upon gluconeogenic induction is shown to involve reduced activation of cAMP response element-binding (CREB) transcription factor.

CONCLUSIONS

The present results demonstrate that free-FAs directly inhibit the induced gluconeogenic response in hepatocytes. Hence, high levels of free-FAs may attenuate hepatic gluconeogenesis, and liver glucose output.

Timed high-fat diet resets circadian metabolism and prevents obesity

Disruption of circadian rhythms leads to obesity and metabolic disorders. Timed restricted feeding (RF) provides a time cue and resets the circadian clock, leading to better health. In contrast, a high-fat (HF) diet leads to disrupted circadian expression of metabolic factors and obesity. We tested whether long-term (18 wk) clock resetting by RF can attenuate the disruptive effects of diet-induced obesity. Analyses included liver clock gene expression, locomotor activity, blood glucose, metabolic markers, lipids, and hormones around the circadian cycle for a more accurate assessment. Compared with mice fed the HF diet ad libitum, the timed HF diet restored the expression phase of the clock genes Clock and Cry1 and phase-advanced Per1, Per2, Cry2, Bmal1, Rorα, and Rev-erbα. Although timed HF-diet-fed mice consumed the same amount of calories as ad libitum low-fat diet-fed mice, they showed 12% reduced body weight, 21% reduced cholesterol levels, and 1.4-fold increased insulin sensitivity. Compared with the HF diet ad libitum, the timed HF diet led to 18% lower body weight, 30% decreased cholesterol levels, 10% reduced TNF-α levels, and 3.7-fold improved insulin sensitivity. Timed HF-diet-fed mice exhibited a better satiated and less stressed phenotype of 25% lower ghrelin and 53% lower corticosterone levels compared with mice fed the timed low-fat diet. Taken together, our findings suggest that timing can prevent obesity and rectify the harmful effects of a HF diet.

Oxidative stress impairs HIF1α activation: a novel mechanism for increased vulnerability of steatotic hepatocytes to hypoxic stress

Steatosis increases the sensitivity of hepatocytes to hypoxic injury. Thus, this study was designed to elucidate the role of hypoxia-inducible factor-1α (HIF1α) in steatotic hepatocytes during hypoxia. AML12 hepatocytes and isolated rat hepatocytes were treated with a free fatty acid mixture of oleate and palmitate (2:1, 1 mM) for 18 h, which generated intrahepatocyte fat accumulation. The cells were then exposed to hypoxia (1% oxygen, 6-24 h). After hypoxia, a further increase in cellular fat accumulation was seen. In steatotic hepatocytes, a decreased HIF1α activation by hypoxia was observed. The capacity of these cells to express HIF1α-dependent genes responsible for the utilization of nutrients for energy was also impaired. This resulted in significantly lower intracellular ATP levels and greater cell death in steatotic hepatocytes compared with control hepatocytes. In contrast, overexpression of constitutively active HIF1α significantly increased cell viability as well as ATP and GLUT1 mRNA levels in steatotic hepatocytes under hypoxia. Hypoxia significantly enhanced HIF1α mRNA levels in control but not in steatotic hepatocytes. Concomitantly, an increase in oxidative stress was found in steatotic hepatocytes under hypoxic conditions compared with control cells. This included higher reactive oxygen species generation, lower cellular and nuclear GSH levels, and higher accumulation of 4-hydroxynonenal protein adducts. Hypoxia-mediated oxidative stress was accompanied by inactivation of basal nuclear factor-κB (NF-κB) DNA binding. Treatment with N-acetyl-l-cysteine, a reducing agent, improved NF-κB DNA-binding capacity and restored HIF1α induction. Conversely, overexpression of an NF-κB super-suppressor in control hepatocytes (IκBαΔN-transfected cells) resulted in complete inhibition of HIF1α expression, confirming that indeed NF-κB regulates HIF1α expression in hypoxic hepatocytes. In conclusion, hypoxia in combination with hepatic steatosis was shown to promote augmented oxidative stress, leading to NF-κB inactivation and impaired HIF1α induction and thereby increased susceptibility to hypoxic injury.

Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats

Olive tree (Olea europaea L.) leaves have been widely used in traditional remedies in European and Mediterranean countries as extracts, herbal teas, and powder. They contain several potentially bioactive compounds that may have hypoglycemic properties. To examine the efficacy of 500 mg oral olive leaf extract taken once daily in tablet form versus matching placebo in improving glucose homeostasis in adults with type 2 diabetes (T2DM). In this controlled clinical trial, 79 adults with T2DM were randomized to treatment with 500 mg olive leaf extract tablet taken orally once daily or matching placebo. The study duration was 14 weeks. Measures of glucose homeostasis including Hba1c and plasma insulin were measured and compared by treatment assignment. In a series of animal models, normal, streptozotocin (STZ) diabetic, and sand rats were used in the inverted sac model to determine the mechanism through which olive leaf extract affected starch digestion and absorption. In the randomized clinical trial, the subjects treated with olive leaf extract exhibited significantly lower HbA1c and fasting plasma insulin levels; however, postprandial plasma insulin levels did not differ significantly by treatment group. In the animal models, normal and STZ diabetic rats exhibited significantly reduced starch digestion and absorption after treatment with olive leaf extract compared with intestine without olive leaf treatment. Reduced digestion and absorption was observed in both the mucosal and serosal sides of the intestine. Though reduced, the decline in starch digestion and absorption did not reach statistical significance in the sand rats. Olive leaf extract is associated with improved glucose homeostasis in humans. Animal models indicate that this may be facilitated through the reduction of starch digestion and absorption. Olive leaf extract may represent an effective adjunct therapy that normalizes glucose homeostasis in individuals with diabetes.

Anti-diabetic activity of Chiliadenus iphionoides

ETHNOPHARMACOLOGICAL RELEVANCE

Chiliadenus iphionoides (Boiss. & Blanche) Brullo (Asteraceae), a small aromatic shrub found throughout Israel, is used traditionally in the treatment of diabetes mellitus. In this study, Chiliadenus iphionoides anti-diabetic activity was characterized using cellular and animal models.

MATERIALS AND METHODS

Pancreatic β cells, adipocytes, and skeletal myotubes were treated with an ethanolic extract of Chiliadenus iphionoides to study the extract's effects on insulin secretion and glucose uptake. The sand rat (Psammomys obesus) was used to study Chiliadenus iphionoides acute and long term effects in vivo. An oral starch tolerance test was performed as well as a 30 day feeding study.

RESULTS

Chiliadenus iphionoides extract increased insulin secretion in β cells as well as glucose uptake in adipocytes and skeletal myotubes. The extract also displayed hypoglycemic activity in the diabetic sand rat.

CONCLUSIONS

Chiliadenus iphionoides exhibits considerable anti-diabetic activity, although the mechanism of action remains to be determined.

Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner

This study was designed to investigate the effect of a low-calorie diet with carbohydrates eaten mostly at dinner on anthropometric, hunger/satiety, biochemical, and inflammatory parameters. Hormonal secretions were also evaluated. Seventy-eight police officers (BMI >30) were randomly assigned to experimental (carbohydrates eaten mostly at dinner) or control weight loss diets for 6 months. On day 0, 7, 90, and 180 blood samples and hunger scores were collected every 4 h from 0800 to 2000 hours. Anthropometric measurements were collected throughout the study. Greater weight loss, abdominal circumference, and body fat mass reductions were observed in the experimental diet in comparison to controls. Hunger scores were lower and greater improvements in fasting glucose, average daily insulin concentrations, and homeostasis model assessment for insulin resistance (HOMA(IR)), T-cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels were observed in comparison to controls. The experimental diet modified daily leptin and adiponectin concentrations compared to those observed at baseline and to a control diet. A simple dietary manipulation of carbohydrate distribution appears to have additional benefits when compared to a conventional weight loss diet in individuals suffering from obesity. It might also be beneficial for individuals suffering from insulin resistance and the metabolic syndrome. Further research is required to confirm and clarify the mechanisms by which this relatively simple diet approach enhances satiety, leads to better anthropometric outcomes, and achieves improved metabolic response, compared to a more conventional dietary approach.

Impaired liver glucose production in a murine model of steatosis and endotoxemia: protection by inducible nitric oxide synthase

This study hypothesized that upregulation of inducible nitric oxide synthase (iNOS) would preserve the metabolic status of the liver under conditions of steatosis and acute inflammation. Wild-type C57BL/6J and C57BL/6 iNOS-knockout (-/-) mice were fed a choline-deficient ethionine-supplemented diet (CDE). Mice were also injected with 5 mg/kg lipopolysaccharide (LPS) to induce endotoxemia. Consumption of the CDE diet led to steatosis of the liver and decreased expression of the gluconeogenic genes compared with controls. LPS treatment exacerbated these effects because of inhibition of PGC-1alpha expression, which resulted in hypoglycemia. In steatotic livers, LPS-induced iNOS expression was enhanced. Comparison between wild-type and iNOS-knockout mice under these conditions demonstrated a protective role of iNOS against fatal hypoglycemia. Nitric oxide (NO) signaling effects were confirmed by treatment of hepatocytes in culture with an NO donor, which resulted in increased expression of PGC-1alpha and gluconeogenic genes. In conclusion, iNOS was found to act as a protective protein and provides a possible mechanism by which the liver preserves glucose homeostasis under stress.

Infusion of a lipid emulsion modulates AMPK and related proteins in rat liver, muscle, and adipose tissues

The primary objective of this study was to investigate the impact of lipid oversupply on the AMPK pathway in skeletal muscle, liver, and adipose tissue. Male Wistar rats were infused with lipid emulsion (LE) or phosphate-buffered saline for 5 h/day for 6 days. Muscles exposed to LE for 6 days exhibited increased AMPK and acetyl-CoA carboxylase (ACC) phosphorylation, along with a greater association between AMPK and Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK). No differences in muscle protein phosphatase 2C (PP2C) activity, LKB1 phosphorylation or AMPK and LKB1 association were observed. Muscle ACCbeta, and adiponectin receptor 1 (AdipoR1) mRNA levels and PPARgamma-co-activator 1alpha (PGC1alpha) protein levels were also increased in LE-treated rats. In contrast, AMPK and ACC phosphorylation decreased and PP2C activity increased in rat livers exposed to LE. Hepatic mRNA levels of ACCalpha, PPARalpha, AdipoR1, AdipoR2, and sterol regulatory element-binding protein-1c (SREBP1c) were also reduced after LE infusion. In adipose tissue, there was no significant alteration in AMPK or ACC phosphorylation. These results demonstrate that following lipid oversupply the AMPK pathway was enhanced in rat skeletal muscle while diminished in the liver and was unchanged in adipose tissue. CaMKK in skeletal muscle and PP2C in the liver, at least in part, appear to mediate these alterations. Alterations in AMPK pathway in the liver induced metabolic defects associated with lipid oversupply.

High-fat diet followed by fasting disrupts circadian expression of adiponectin signaling pathway in muscle and adipose tissue

The circadian clock controls energy homeostasis by regulating circadian expression of proteins involved in metabolism. Disruption of circadian rhythms leads to obesity and metabolic disorders. Little is known regarding the control of the biological clock over adiponectin signaling pathway in adipose tissue, the adiponectin producer, and muscle, an adiponectin target tissue under fasting, low-fat (LF), or high-fat (HF) diet. Mice were fed LF or HF diet for 7 weeks and fasted on the last day. The circadian mRNA expression of clock genes and components of adiponectin metabolic pathway (mAdipoR1, mAdipoR2, mPparalpha, mPpargamma, mAmpk, and mAcc) in the muscle and adipose tissue were tested. Using average daily levels of multiple time points around the circadian cycle, we assessed mRNA levels of the different adiponectin signaling components. In addition, serum glucose, adiponectin, and insulin were measured. Under LF diet, adiponectin signaling pathway components exhibited circadian rhythmicity at the mRNA levels. Fasting and HF diet followed by fasting disrupted this circadian expression causing a phase advance or delay, respectively. Changes were also found in the expression levels of adiponectin receptor, mAmpk, mAcc, mPparalpha, and mPpargamma reflecting a defect in adiponectin signaling. As both peroxisome proliferator-activated receptor alpha (PPARalpha) and mAMPK are linked to the core clock mechanism, they could mediate the disruptions seen in clock gene expression under HF diet. In turn, the circadian clock affects the daily rhythm of these adiponectin signaling components.

Triacylglycerol-induced impairment in mitochondrial biogenesis and function in J774.2 and mouse peritoneal macrophage foam cells

The aim of this study was to detect mitochondrial alterations in J774.2 macrophages and mouse peritoneal macrophages (MPM) foam cells. J774.2 and MPM cells were exposed to triacylglycerol (TG) emulsion (1 mg/ml) for induction of fat accumulation. Impairment of mitochondrial function was reflected by reduced cellular ATP production and decreased expression of subunits of mitochondrial complexes I and III. The expression of subunit IV of complex IV remained unchanged, however, the content of its precursor in cells increased. Inhibitors of mitochondrial complexes, rotenone (0.1 microM) and myxothiazol (25 nM), protected the viability in TG-loaded macrophages. The exposure to TG caused downregulation of PPARgamma coactivator (PGC)-1alpha and nuclear respiratory factor (NRF)-1. Activation of peroxisome proliferator-activated receptors attenuated reactive oxygen species production in the foam cells. Treatment with antioxidant N-acetylcysteine (NAC) prevented lipid-mediated mitochondrial and cellular damage. In conclusion, this study demonstrates the important role of mitochondrial biogenesis dysfunction in TG-induced lipotoxicity in macrophages.

High-fat diet delays and fasting advances the circadian expression of adiponectin signaling components in mouse liver

The circadian clock controls energy homeostasis by regulating circadian expression and/or activity of enzymes involved in metabolism. Disruption of circadian rhythms may lead to obesity and metabolic disorders. We tested whether the biological clock controls adiponectin signaling pathway in the liver and whether fasting and/or high-fat (HF) diet affects this control. Mice were fed low-fat or HF diet and fasted on the last day. The circadian expression of clock genes and components of adiponectin metabolic pathway in the liver was tested at the RNA, protein, or enzyme activity level. In addition, serum levels of glucose, adiponectin, and insulin were measured. Under low-fat diet, adiponectin signaling pathway components exhibited circadian rhythmicity. However, fasting and HF diet altered this circadian expression; fasting resulted in a phase advance, and HF diet caused a phase delay. In addition, adenosine monophosphate-activated protein kinase levels were high during fasting and low during HF diet. Changes in the phase and daily rhythm of clock genes and components of adiponectin signaling pathway as a result of HF diet may lead to obesity and may explain the disruption of other clock-controlled output systems, such as blood pressure and sleep/wake cycle, usually associated with metabolic disorders.