Impact of nutrition and obesity on chronic liver disease

Emerging N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD quinone in paired human plasma and urine from Tianjin, China: Preliminary assessment with demographic factors

With increasing concerns about N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD-quinone (6PPD-Q), relevant environmental investigations and toxicological research have sprung up in recent years. However, limited information could be found for human body burden assessment. This work collected and analyzed 200 samples consisting of paired urine and plasma samples from participants (50 male and 50 female) in Tianjin, China. Low detection frequencies (DF, <15 %) were found except for urinary 6PPD-Q (86 %), which suggested the poor residue tendency of 6PPD and 6PPD-Q in blood. The low DFs also lead to no substantial association between two chemicals. Data analysis based on urinary 6PPD-Q showed a significant difference between males and females (p < 0.05). No significant correlation was found for other demographic factors (Body Mass Index (BMI), age, drinking, and smoking). The mean values of daily excretion (ng/kg bw/day) calculated using urinary 6PPD-Q for females and males were 7.381 ng/kg bw/day (female) and 3.360 ng/kg bw/day (male), and apparently female suffered higher daily exposure. Further analysis with daily excretion and ALT (alanine aminotransferase)/TSH (thyroid stimulating hormone)/ blood cell analysis indicators found a potential correlation with 6PPD-Q daily excretion and liver/immune functions. Considering this preliminary assessment, systematic research targeting the potential organs at relevant concentrations is required.

Bariatric surgery, obesity and liver transplantation

The obesity epidemic has profoundly impacted the epidemiology and trends of liver disease. In the current era, non-alcoholic fatty liver disease (NAFLD) progressing to non-alcoholic steatohepatitis (NASH) has emerged as the second leading indication for liver transplant (LT) and has been associated with the rising rates of hepatocellular carcinoma (HCC) with and without underlying cirrhosis. Obesity has been associated with poor post-transplant outcomes including lower patient and graft survival; higher risk of post-operative metabolic complications; poor wound healing; and higher infection rates. Bariatric surgery is currently the most effective management of morbid obesity and has been offered to patients both in the pre and post LT setting. The techniques attempted in LT recipients most commonly include sleeve gastrectomy (SG), gastric bypass surgery with few cases of gastric banding and biliopancreatic diversion. However, there is lack of evidence-based data on the optimal management for patients with obesity and who are liver transplant candidates and/or recipients. In the following discussion, we present the highlights from a review of the literature.

Inhibition of PU.1 ameliorates metabolic dysfunction and non-alcoholic steatohepatitis

BACKGROUND & AIMS

Obesity is a well-established risk factor for type 2 diabetes (T2D) and non-alcoholic steatohepatitis (NASH), but the underlying mechanisms remain incompletely understood. Herein, we aimed to identify novel pathogenic factors (and possible therapeutic targets) underlying metabolic dysfunction in the liver.

METHODS

We applied a tandem quantitative proteomics strategy to enrich and identify transcription factors (TFs) induced in the obese liver. We used flow cytometry of liver cells to analyze the source of the induced TFs. We employed conditional knockout mice, shRNA, and small-molecule inhibitors to test the metabolic consequences of the induction of identified TFs. Finally, we validated mouse data in patient liver biopsies.

RESULTS

We identified PU.1/SPI1, the master hematopoietic regulator, as one of the most upregulated TFs in livers from diet-induced obese (DIO) and genetically obese (db/db) mice. Targeting PU.1 in the whole liver, but not hepatocytes alone, significantly improved glucose homeostasis and suppressed liver inflammation. Consistently, treatment with the PU.1 inhibitor DB1976 markedly reduced inflammation and improved glucose homeostasis and dyslipidemia in DIO mice, and strongly suppressed glucose intolerance, liver steatosis, inflammation, and fibrosis in a dietary NASH mouse model. Furthermore, hepatic PU.1 expression was positively correlated with insulin resistance and inflammation in liver biopsies from patients.

CONCLUSIONS

These data suggest that the elevated hematopoietic factor PU.1 promotes liver metabolic dysfunction, and may be a useful therapeutic target for obesity, insulin resistance/T2D, and NASH.

LAY SUMMARY

Expression of the immune regulator PU.1 is increased in livers of obese mice and people. Blocking PU.1 improved glucose homeostasis, and reduced liver steatosis, inflammation and fibrosis in mouse models of non-alcoholic steatohepatitis. Inhibition of PU.1 is thus a potential therapeutic strategy for treating obesity-associated liver dysfunction and metabolic diseases.

The Complex Interactions Between Obesity, Metabolism and the Brain

Obesity is increasing at unprecedented levels globally, and the overall impact of obesity on the various organ systems of the body is only beginning to be fully appreciated. Because of the myriad of direct and indirect effects of obesity causing dysfunction of multiple tissues and organs, it is likely that there will be heterogeneity in the presentation of obesity effects in any given population. Taken together, these realities make it increasingly difficult to understand the complex interplay between obesity effects on different organs, including the brain. The focus of this review is to provide a comprehensive view of metabolic disturbances present in obesity, their direct and indirect effects on the different organ systems of the body, and to discuss the interaction of these effects in the context of brain aging and the development of neurodegenerative diseases.

Vitamin B6 improves blood parameters in rats fed a protein-deficient diet and subjected to moderate, long-term exercise

Vitamin B₆ is necessary for many enzymatic pathways (glucose and lipid metabolism, DNA/RNA synthesis, or modulation of gene expression) and affects immune cell function and blood-forming processes. We hypothesised that supplementing a protein-deficient diet with vitamin B₆ may reduce the negative impact of protein malnutrition. Here, we evaluated the effect of moderate, long-term exercise (ninety days) on selected blood parameters in rats fed a normal diet, a protein-deficient diet, or a protein-deficient diet supplemented with vitamin B₆. Selected haematological, immunological, and biochemical parameters were examined. A protein-deficient diet lasting 90 days caused significant reduction in body mass, increased activity of aminotransferases (asparagine and alanine), an increased percentage of innate cells in the blood, and decreased haemoglobin concentration in the blood. Adding vitamin B₆ significantly increased body and muscle mass, decreased liver parameters, and caused normalisation of haemoglobin concentration and the proportion of white blood cells in the blood. These results indicate that vitamin B₆ supplementation significantly improves the health of protein-malnourished rats and paves the way for the development of novel anti-malnutrition therapies.

Associations between fatty liver index and asymptomatic intracranial vertebrobasilar stenosis in Chinese population

Metabolic diseases such as type 2 diabetes mellitus (T2DM) and metabolic syndromes (MetS) have been recognized as the important risk factors for asymptomatic intracranial vertebrobasilar stenosis (IVBS). Although fatty liver index (FLI) is significantly related with these diseases, the association between FLI and IVBS remains unclear. In the present study, 2368 participants (30–75 years) were recruited from a Chinese prospective cohort study of PMMJS. Amongst them, 2281 individuals who did not have IVBS at baseline were enrolled in the 6-year following-up study. In cross-sectional analysis based on the baseline characteristics, the results showed that FLI was positively related with IVBS prevalence. Compared to the participants with FLI < 30, the adjusted OR (95% CI) of IVBS was 2.07 (1.18, 3.62) and 2.85 (1.39, 5.18) in the groups of 30 ≤ FLI < 60 and FLI ≥ 60, respectively. In longitudinal analysis, the results showed that the participants with FLI ≥ 60 had an increased risk of asymptomatic IVBS compared to those with FLI < 30 [adjusted HR (95%CI): 1.65 (1.05, 2.60)]. Moreover, exclusion of persons with hypertension, T2DM and MetS did not alter the associations between FLI and asymptomatic IVBS. Therefore, our results suggest that elevated FLI is an independent risk factor for asymptomatic IVBS in Chinese adults.

Malnutrition and Nutritional Support in Alcoholic Liver Disease: a Review

Malnutrition is associated with alcoholic liver disease (ALD) and related complications such as hepatic encephalopathy and increased rate of infections. Avoidance of prolonged fasting and overly restrictive diets is important to avoid poor nutrition. Adequate intake of calories, protein, and micronutrients via frequent small meals and evening supplements and/or enteral and parenteral nutrition when indicated has been associated with reduced mortality and morbidity in patients with ALD. Modification of protein/fat sources and composition in addition to probiotic supplementation are promising interventions for decreased progression of ALD and its complications.

Nutrition Interventions for Chronic Liver Diseases and Nonalcoholic Fatty Liver Disease

The progressively increasing rates of obesity have led to a worldwide epidemic of nonalcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome. It is currently the most common cause of liver disease worldwide and projected to be the leading indication for liver transplantation in the United States by 2020. NAFLD is associated with both liver-related and overall mortality. Undoubtedly, nutrition interventions are key in the treatment of NAFLD, to reverse the disease, and prevent disease progression, complications, and associated comorbidities, including cardiovascular disease and diabetes.

Diagnosis and treatment of nutritional deficiencies in alcoholic liver disease: Overview of available evidence and open issues

Malnutrition is common in alcoholic liver disease and is associated with high rates of complications and mortality. In this article, the current literature was reviewed to highlight the relevance of proper nutritional management providing levels of evidence, when available. A PubMed search was performed for English-language publications from 1980 through 2014 with the keywords: alcoholic liver disease, nutritional deficiencies, nutritional support, enteral nutrition, parenteral nutrition, and protein-energy malnutrition. Manuscripts focused on nutritional approach in patients with alcoholic liver disease were selected. Although nutritional support for malnourished patients improves the outcome of hospitalization, surgery, transplantation and reduces the complications of liver disease and the length of hospital stay, specific guidelines are scanty. Both enteral and parenteral nutrition appear to improve nutritional parameters and liver function; however data on survival is often conflicting. As micronutrient depletion is common in alcoholic liver disease and each deficiency produces specific sequelae, all cirrhotic patients should be screened at baseline for deficiencies of micronutrient and supplemented as needed. In summary, protein-energy malnutrition and micronutrient depletion are clinical concerns in alcoholic liver disease. Nutritional therapy, including enteral nutrition, parenteral nutrition and micronutrient supplementation should be part of the multidisciplinary management of these patients.

The influence of vitamin B12 supplementation on the level of white blood cells and lymphocytes phenotype in rats fed a low-protein diet

Protein malnutrition has a negative effect on body composition and some blood parameters, especially in the young growing organism. One of nutritional factors which could protect against negative consequences of protein deficiency may be B group vitamins. The aim of the study was to investigate the effect of vitamin B12 supplementation on the immune system in rats fed a standard and a low-protein diet. Rats were fed a control (20% of energy from protein) or a protein-deficient diet (4.5% of energy from protein). Half of animals in each group were additionally supplemented with vitamin B12 (300% of the daily intake). The white blood cells analysis and lymphocytes immunophenotyping (number and percentage) were performed. Low-protein diets caused disturbances in WBC and lymphocyte subpopulations in both short- (30-day) as well as long-term periods (90-day). Vitamin B12 supplementation significantly reduced the negative impact of protein malnutrition after 30 days, however had no effect on long-term malnutrition. Furthermore, vitamin B12 addition in rats fed a control diet did not affect the studied parameters. This observation opens the promise of use of vitamin B12 supplementation to improve immune system parameters in protein malnourished organisms.