Second World Congress on the Insulin Resistance Syndrome: insulin resistance syndrome and nonalcoholic fatty liver disease

Diabetes and Cancer: Metabolic Association, Therapeutic Challenges, and the Role of Natural Products

Cancer is considered the second leading cause of death worldwide and in 2018 it was responsible for approximately 9.6 million deaths. Globally, about one in six deaths are caused by cancer. A strong correlation was found between diabetes mellitus and carcinogenesis with the most evident correlation was with type 2 diabetes mellitus (T2DM). Research has proven that elevated blood glucose levels take part in cell proliferation and cancer cell progression. However, limited studies were conducted to evaluate the efficiency of conventional therapies in diabetic cancer patients. In this review, the correlation between cancer and diabetes will be discussed and the mechanisms by which the two diseases interact with each other, as well as the therapeutics challenges in treating patients with diabetes and cancer with possible solutions to overcome these challenges. Natural products targeting both diseases were discussed with detailed mechanisms of action. This review will provide a solid base for researchers and physicians to test natural products as adjuvant alternative therapies to treat cancer in diabetic patients.

The clinical application of metformin in children and adolescents: A short update

Metformin is a widely used drug that results in clear benefits in relation to glucose metabolism and diabetes-related complications. The global increase in the prevalence of obesity among children and adolescents is accompanied by the appearance and increasing prevalence of insulin resistance, prediabetes, and type 2 diabetes mellitus (T2DM). In addition, children, and adolescents with premature pubarche and polycystic ovary have considerable degree of insulin resistance. The insulin sensitizing actions of metformin encouraged many investigators and physician to use it as the key drug in these conditions for both prevention and treatment. However, long term-controlled studies are still required to assess the degree and duration of effectiveness and safety of using metformin. This review tries to update physicians about the main and the new therapeutic perspectives of this drug.

CDK4/6 Inhibitors in Breast Cancer Treatment: Potential Interactions with Drug, Gene, and Pathophysiological Conditions

Palbociclib, ribociclib, and abemaciclib belong to the third generation of cyclin-dependent kinases inhibitors (CDKis), an established therapeutic class for advanced and metastatic breast cancer. Interindividual variability in the therapeutic response of CDKis has been reported and some individuals may experience increased and unexpected toxicity. This narrative review aims at identifying the factors potentially concurring at this variability for driving the most appropriate and tailored use of CDKis in the clinic. Specifically, concomitant medications, pharmacogenetic profile, and pathophysiological conditions could influence absorption, distribution, metabolism, and elimination pharmacokinetics. A personalized therapeutic approach taking into consideration all factors potentially contributing to an altered pharmacokinetic/pharmacodynamic profile could better drive safe and effective clinical use.

Thiazolidinediones for nonalcoholic steatohepatitis: A meta-analysis of randomized clinical trials

The findings regarding the effects of thiazolidinediones (TZDs) in nonalcoholic steatohepatitis (NASH) patients have been inconsistent, and the assessment of different clinical variables for evaluating the effects of TZDs confound a direct comparison of the results of different randomized clinical trials (RCTs), especially with regard to lifestyle changes. In this paper, we performed a meta-analysis of randomized controlled trials to clarify the effects of TZD treatment with and without lifestyle changes on histological markers of NASH and clinical variables related to insulin resistance (IR), hyperlipidemia, and obesity. We searched the literature using the following MeSH terms: "nonalcoholic steatohepatitis," "non-alcoholic steatohepatitis," "thiazolidinedione," "pioglitazone," "rosiglitazone," "randomized," and "clinical trial." Five eligible RCTs were selected, in which patients were treated with either pioglitazone or rosiglitazone, with or without lifestyle changes. We compared the effects of TZD treatment on hepatic fibrosis, lobular inflammation, IR improvement, fasting serum insulin, adiposity, and dyslipidemia between the various studies using fixed and random effects models, and heterogeneity in clinical outcomes was assessed. Significant improvement in hepatic fibrosis did not occur among the patients treated with TZDs alone or in those who underwent both lifestyle changes and TZD therapy. Lobular inflammation decreased in NASH patients who received TZD treatment and in those who underwent both TZD therapy and lifestyle changes. Although TZD treatment resulted in no significant improvement in IR, NASH patients who underwent both lifestyle changes and TZD therapy experienced a significantly greater reduction in their fasting insulin level than that observed in the control patients, whereas patients treated with TZDs alone did not. Although TZD-treated patients experienced significantly greater weight gain than the control patients, TZD treatment had no significant impact on body-mass index, percentage of body fat, or serum levels of cholesterol and triglyceride. Our findings indicate that additional variables should be assessed to obtain a more comprehensive evaluation of the effects of TZD treatment on IR and comorbidity risk factors in NASH patients, and suggest that including lifestyle changes and additional insulin-sensitizing agents in TZD regimens might improve the benefits of TZD therapy for NASH.

Association between lipoprotein(a) and nonalcoholic fatty liver disease among Korean adults

BACKGROUND

Lipoprotein(a) [Lp(a)] and nonalcoholic fatty liver disease (NAFLD) are risk factors for cardiovascular diseases. We investigated the relationship between Lp(a) concentrations and NAFLD among Korean adults.

METHODS

A total of 2242 nondiabetic subjects undergoing routine health screening examination were enrolled. Anthropometric and biochemical parameters, including Lp(a) were measured. NAFLD were assessed by ultrasonography. Adjusted Odds ratios for the presence of NAFLD according to Lp(a) tertiles were estimated using logistic regression.

RESULTS

Subjects were grouped according to the severity of NAFLD and Lp(a) concentrations. Lp(a) concentrations were decreased across the severity of NAFLD and the prevalence of NAFLD decreased with the Lp(a) tertiles. Compared with subjects in the lowest tertile of Lp(a), those in the highest tertile had higher total cholesterol and LDL-C concentrations and lower body mass index, blood pressure, fasting glucose, triglyceride, ALT, and HOMA-IR concentrations. In the logistic regression analysis after adjusting for multiple risk factors, the relationship between Lp(a) concentrations and the presence of NAFLD remained significant. However, this association was attenuated after adjusting for insulin resistance.

CONCLUSIONS

Lp(a) was inversely associated with the presence of NAFLD, but it was not an independent risk factor for NAFLD among Korean adults.

Identification of reciprocal causality between non-alcoholic fatty liver disease and metabolic syndrome by a simplified Bayesian network in a Chinese population

OBJECTIVES

It remains unclear whether non-alcoholic fatty liver disease (NAFLD) is a cause or a consequence of metabolic syndrome (MetS). We proposed a simplified Bayesian network (BN) and attempted to confirm their reciprocal causality.

SETTING

Bidirectional longitudinal cohorts (subcohorts A and B) were designed and followed up from 2005 to 2011 based on a large-scale health check-up in a Chinese population.

PARTICIPANTS

Subcohort A (from NAFLD to MetS, n=8426) included the participants with or without NAFLD at baseline to follow-up the incidence of MetS, while subcohort B (from MetS to NAFLD, n=16,110) included the participants with or without MetS at baseline to follow-up the incidence of NAFLD.

RESULTS

Incidence densities were 2.47 and 17.39 per 100 person-years in subcohorts A and B, respectively. Generalised estimating equation analyses demonstrated that NAFLD was a potential causal factor for MetS (relative risk, RR, 95% CI 5.23, 3.50 to 7.81), while MetS was also a factor for NAFLD (2.55, 2.23 to 2.92). A BN with 5 simplification strategies was used for the reciprocal causal inference. The BN's causal inference illustrated that the total effect of NAFLD on MetS (attributable risks, AR%) was 2.49%, while it was 19.92% for MetS on NAFLD. The total effect of NAFLD on MetS components was different, with dyslipidemia having the greatest (AR%, 10.15%), followed by obesity (7.63%), diabetes (3.90%) and hypertension (3.51%). Similar patterns were inferred for MetS components on NAFLD, with obesity having the greatest (16.37%) effect, followed by diabetes (10.85%), dyslipidemia (10.74%) and hypertension (7.36%). Furthermore, the most important causal pathway from NAFLD to MetS was that NAFLD led to elevated GGT, then to MetS components, while the dominant causal pathway from MetS to NAFLD began with dyslipidaemia.

CONCLUSIONS

The findings suggest a reciprocal causality between NAFLD and MetS, and the effect of MetS on NAFLD is significantly greater than that of NAFLD on MetS.

Effect of combined prescription and separate prescription of promoting blood circulation and removing blood stasis traditional Chinese medicine on expression of SOCS-3 and SREBP-1c in diabetic fatty liver in rats

AIM: To investigate the effect of promoting blood circulation and removing blood stasis traditional Chinese medicine on the expression of suppressors of cytokine signaling protein-3 (SOCS-3) and sterol regulatory element binding protein-1c (SREBP-1c) in diabetic fatty liver in rats and to explore potential mechanisms involved.

METHODS: Fifty healthy male Sprague-Dawley rats were randomly divided into five groups: a normal group, a model group, a promoting blood circulation group (salvia miltiorrhiza, rhizoma ligustici, wallichii), a removing blood stasis group (leech, lumbricus), and a combination group (salvia miltiorrhiza, rhizoma ligustici, wallichii, leech, lumbricus). Diabetes was induced with streptozocin (50 mg/kg i.p.) in all the groups except for the normal group. The three treatment groups were intragastrically treated with Chinese traditional medicine which can promote blood circulate and/or remove stasis once a day for 12 wk. Triglyceride (TG) and cholesterol (TC) were measured using biochemical methods. The expression of SOCS-3 and SREBP-1c mRNAs was determined by RT-PCR.

RESULTS: Compared to the normal group, the levels of TG and TC were significantly increased in the model group (6.80 mmol/L ± 0.19 mmol/L, 5.36 mmol/L ± 0.24 mmol/L, 5.37 mmol/L ± 0.25 mmol/L, 5.01 mmol/L ± 0.22 mmol/L vs 3.55 mmol/L ± 0.28 mmol/L, all P < 0.05; 2.26 mmol/ ± 0.27 mmol/L, 1.83 mmol/L ± 0.25 mmol/L, 1.82 mmol/L ± 0.23 mmol/L, 1.58 mmol/L ± 0.19 mmol/L vs 1.35 mmol/L ± 0.16 mmol/L, all P < 0.05); however, the levels of TG and TC were significantly lower in each drug intervention group than in the model group (5.36 mmol/L ± 0.24 mmol/L, 5.37 mmol/L ± 0.25 mmol/L, 5.01 mmol/L ± 0.22 mmol/L vs 6.80 mmol/L ± 0.19 mmol/L, all P < 0.05; 1.83 mmol/L ± 0.25mmol/L, 1.82 mmol/L ± 0.23 mmol/L, 1.58 mmol/L ± 0.19 mmol/L vs 2.21 mmol/L ± 0.21 mmol/L, all P < 0.05). The levels of TG and TC were significantly higher in the promoting blood circulation group and removing blood stasis group than in the combination group (5.01 mmol/L ± 0.22 mmol/L vs 5.36 mmol/L ± 0.24 mmol/L, 5.37 mmol/L ± 0.25 mmol/L, both P < 0.05; 1.58 mmol/L ± 0.19 mmol/L vs 1.83 mmol/L ± 0.25 mmol/L, 1.82 mmol/L ± 0.23 mmol/L, both P < 0.05). There was no significant change in the levels of TG and TC between the promoting blood circulation group and removing blood stasis group. Compared to the model group, liver steatosis was significantly reduced in each drug intervention group; however, liver steatosis was significantly more serious in the promoting blood circulation group and removing blood stasis group than in the combination group. Compared to the normal group, the expression of SOCS-3 and SREBP-1c mRNAs was significantly increased in the model group (0.885 ± 0.227, 0.778 ± 0.005, 0.633 ± 0.678, 0.475 ± 0.012 vs 0.189 ± 0.002, all P < 0.05; 0.861 ± 0.020, 0.751 ± 0.003, 0.600 ± 0.005, 0.382 ± 0.014 vs 0.176 ± 0.001, all P < 0.05). However, the expression of SOCS-3 and SREBP-1c mRNAs was significantly lower in each drug intervention group than in the model group (0.778 ± 0.005, 0.633 ± 0.678, 0.475 ± 0.012 vs 0.885 ± 0.227, both P < 0.05; 0.751 ± 0.003, 0.600 ± 0.005, 0.382 ± 0.014 vs 0.861 ± 0.020, both P < 0.05). The expression of SOCS-3 and SREBP-1c mRNAs was significantly higher in the promoting blood circulation group and removing blood stasis group than in the combination group (0.751 ± 0.003, 0.600 ± 0.005 vs 0.382 ± 0.014, both P < 0.05; 0.778 ± 0.005, 0.633 ± 0.678 vs 0.475 ± 0.012, both P < 0.05).

CONCLUSION: Both combined prescription and separate prescription of promoting blood circulation and removing blood stasis traditional Chinese medicine can alleviate fatty liver in rats possibly by decreasing the expression of SOCS-3 and SREBP-1c mRNAs. Combined prescription is better than separate prescription in alleviating fatty liver.

The alanine aminotransferase to triglycerides ratio as a marker to identify nonalcoholic fatty liver disease

OBJECTIVE

The aim of this study was to determine whether the alanine aminotransferase to triglycerides (ALT/TGL) ratio is useful to identify nonalcoholic fatty liver disease (NAFLD) in asymptomatic overweight and obese women.

METHODS

Asymptomatic overweight and obese women aged 20-65 years were enrolled in a cross-sectional study for evaluating their ALT/TGL ratio, which was considered as a diagnostic test for identifying NAFLD. Alcohol consumption of at least 20 g/week, smoking, positive markers of viral or autoimmune hepatitis, a previous diagnosis of acute or chronic liver disease, renal failure, glomerulopathies, neoplasia, cardiovascular disease, and intake of contraceptives or hepatotoxic drugs were the exclusion criteria. The sensitivity, specificity, and predictive values were calculated. The optimal ALT/TGL ratio to identify NAFLD was determined using a receiver operating characteristic scatter plot analysis.

RESULTS

A total of 412 asymptomatic women, average age of 45.1 ± 10.5 years, were enrolled, 199 (48.3%) without NAFLD and 213 (51.7%) with NAFLD. The best cut-off point of the ALT/TGL ratio to identify NAFLD was 7.0, which showed the highest sensitivity (84.0%) and specificity (91.0%). For this cut-off point, the positive and negative predictive values were 91.8 and 84.3%, respectively. The weighted κ test showed a good agreement between the ALT/TGL ratio and the hepatic ultrasound in the identification of NAFLD (κ = 0.758).

CONCLUSION

The results of this study indicate that the ALT/TGL ratio has a high sensitivity and specificity to identify NAFLD, suggesting that it could be a useful marker to recognize NAFLD in asymptomatic overweight and obese women.

Non-alcoholic fatty liver disease impairs hippocampal-dependent memory in male rats

Non-alcoholic fatty liver disease (NAFLD) is a disorder observed in children and adults characterized by an accumulation of liver fat (>5% wet weight) in the absence of excessive alcohol intake. NAFLD affects 10 to 30% of the American population and is the most common cause of liver disease in the United States. NAFLD leads to serious disturbances in cardiovascular and hormonal function; however, possible effects on brain function have been overlooked. The aims of the present study were to test whether diet-induced NAFLD impairs hippocampal-dependent memory and to determine whether any observed deficits are associated with changes in hippocampal insulin signaling or concentrations of brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1). Post-weanling male Sprague-Dawley rats were fed a high fructose (60% of calories) or control diet for 12 weeks and then trained and tested in a spatial water maze. NAFLD was confirmed with postmortem measures of liver mass and liver lipid concentrations. NAFLD did not affect acquisition of the spatial water maze, but did impair retention tested 48 h later. Specifically, both groups demonstrated similar decreases in latency to swim to the escape platform over training trials, but on the memory test NAFLD rats took longer to reach the platform and made fewer visits to the platform location than control diet rats. There were no differences between the groups in terms of insulin-stimulated phosphorylation of insulin receptor β subunit (IR-β) and protein kinase B (PKB/AKT) in hippocampal slices or hippocampal BDNF or IGF-1 concentrations. Thus, these data indicate that NAFLD impairs hippocampal-dependent memory function and that the deficit does not appear attributable to alterations in hippocampal insulin signaling or hippocampal BDNF or IGF-1 concentrations.

Protective effect of alcohol consumption for fatty liver but not metabolic syndrome

AIM: To investigate the effect of alcohol on the metabolic syndrome (MS) and fatty liver in Japanese men and women.

METHODS: A cross-sectional study was conducted in a medical health checkup program at a general hospital. This study involved 18 571 Japanese men and women, 18-88 years of age, with a mean body mass index of 22.6 kg/m². A standardized questionnaire was administered. The total amount of alcohol consumed per week was calculated, and categorized into four grades. Fatty liver was examined by ultrasound modified criteria of the revised National Cholesterol Education Program Adult Treatment Panel III and the new International Diabetes Federation.

RESULTS: The prevalence of fatty liver decreased in men and women with light to moderate alcohol consumption, whereas the prevalence of MS was not so changed. The prevalence of fatty liver of any grade in men was lower than that in those with no or minimal alcohol consumption. In women with light to moderate alcohol consumption, prevalence of fatty liver was lower than that in women with no or minimal alcohol consumption. By logistic regression analysis, the odds ratio (OR) for MS in women with light alcohol consumption was decreased to < 1.0, but this change was not clear in men. The OR for fatty liver was clearly < 1.0 in men with any level of alcohol consumption and in women with light to moderate consumption.

CONCLUSION: Light to moderate alcohol consumption has a favorable effect for fatty liver, but not for MS in Japanese men and women.

L-carnitine ameliorated fatty liver in high-calorie diet/STZ-induced type 2 diabetic mice by improving mitochondrial function

BACKGROUND

There are an increasing number of patients suffering from fatty liver caused by type 2 diabetes. We intended to study the preventive and therapeutic effect of L-carnitine (LC) on nonalcoholic fatty liver disease (NAFLD) in streptozotocin (STZ)-induced type 2 diabetic mice and to explore its possible mechanism.

METHODS

Thirty male Kungming mice were randomly divided into five groups: control group, diabetic group, pre-treatment group (125 mg/kg BW), low-dose (125 mg/kg BW) therapeutic group and high-dose (250 mg/kg BW) therapeutic group. The morphology of hepatocytes was observed by light and electron microscopy. LC and ALC (acetyl L-carnitine) concentrations in the liver were determined by high-performance liquid chromatography (HPLC). Moreover, liver weight, insulin levels and free fatty acid (FFA) and triglyceride (TG) levels in the liver and plasma were measured.

RESULTS

Average liver LC and ALC levels were 33.7% and 20% lower, respectively, in diabetic mice compared to control mice (P < 0.05). After preventive and therapeutic treatment with LC, less hepatocyte steatosis, clearer crista and fewer glycogen granules in the mitochondria were observed. Decreased liver weight, TG levels, and FFA concentrations (P < 0.05) in the liver were also observed after treatment with LC in diabetic mice. Moreover, liver LC and ALC levels increased upon treatment with LC, whereas the ratio of LC and ALC decreased significantly (P < 0.01).

CONCLUSION

LC supplements ameliorated fatty liver in type 2 diabetic mice by increasing fatty acid oxidation and decreasing the LC/ALC ratio in the liver. Therefore, oral administration of LC protected mitochondrial function in liver.

Thermal and refining processes, not fermentation, tend to reduce lipotropic capacity of plant-based foods

Plant-based foods (PBF) are relevant and diversified sources of lipotropes, which are compounds preventing excess hepatic fat deposits. In a first study, we defined the lipotropic capacity (LC, %) of raw PBF as the means of 8 lipotrope densities (LD, mg/100 kcal), each expressed relative to that of a reference food ranking the highest considering its mean 8 LD ranks (LC(raw asparagus)=100%) (A. Fardet, J.-F. Martin and J. M. Chardigny, J. Food Comp. Anal., 2011, DOI: 10.1016/j.jfca.2011.1003.1013). We showed that vegetables appeared as the best source of lipotropes on a 100 kcal-basis compared to legumes, cereals, fruits and nuts. The main objective of this second study was to quantify the effect of processing on LD and LC of raw PBF based on lipotrope contents collected in a USDA (United State Department of Agriculture) database and the literature, i.e. betaine, choline, myo-inositol, methionine, magnesium, niacin, pantothenic acid and folate contents. Choline and betaine densities were not significantly affected by processing while methionine and lipotropic micronutrient densities were significantly decreased, especially for magnesium, pantothenate and folates. Myo-inositol density decreases were insignificant due to lower product number resulting from limited literature data. Lipotropic micronutrient densities were more affected by processing than other densities. Fermentations increased betaine (median change of +32%) and choline (+34%) densities. Canning and boiling vegetables increased choline densities (+26%). Globally, processing significantly reduced LC by ∼20%, fermentations being less drastic (median change of -5%) than refining (-33%) and thermal treatments (-16%). More specifically, canning increased LC of beetroot (536 vs 390%) and common bean (40 vs 36%) as fermentation towards LC grape (14 vs 7% for wine). Results were then mainly discussed based on percentages of lipotrope content changes on a dry-weight basis. Results of this study also showed that the LC is quite a relevant index to estimate effect of processing on lipotropic potential of PBF.

Altered distribution of caveolin-1 in early liver steatosis

BACKGROUND

Caveolin-1, the main structural protein of caveolae, is involved in cholesterol homoeostasis, transcytosis, endocytosis and signal transduction and thought to play an important role in lipidogenesis. Little is known about the pathophysiological role of caveolin-1 in nonalcoholic fatty liver disease (NAFLD), a condition frequently associated with the metabolic syndrome and characterized by abnormal accumulation of intrahepatic triglycerides with a potentially harmful risk of evolution to liver fibrosis, cirrhosis and hepatocellular carcinoma.

MATERIALS AND METHODS

Liver steatosis (micro/macrovesicular) was induced in adult rats fed a choline-deficient diet for 14days and compared with a control normal diet. The expression and subcellular distribution of caveolin-1 was assessed using light and electron microscopy by immunohistochemical and immunocytochemical techniques and by Western blotting.

RESULTS

Caveolin-1 was mainly associated with the hepatocyte basolateral plasma membrane. Fatty hepatocytes were characterized by a significant increase in the expression of caveolin-1 around and within the lipid droplets as well as in the inner membrane of mitochondria.

CONCLUSIONS

Our data suggest the involvement of caveolin-1 in the case of abnormal lipogenesis and mitochondrial function typical of steatotic hepatocytes in NAFLD. Addressing the role played by caveolin-1 in liver membranes in NAFLD may help future therapeutic choices in a frequent metabolic liver disease.

Hepatic steatosis, carotid atherosclerosis and metabolic syndrome: the STEATO Study

PURPOSE

Hepatic steatosis is frequently observed in subjects with metabolic syndrome (MS). In type 2 diabetics, it is independently associated with cardiovascular diseases. In order to confirm and extend this finding, a large group of patients with risk factors for atherosclerosis was studied.

METHODS

Carotid atherosclerosis was investigated by echo-Doppler, and hepatic steatosis by ultrasound and transaminase values. Strict exclusion criteria were chosen in order to avoid secondary forms of fatty liver and interference on transaminase values.

RESULTS

Among 970 enrolled patients, about 20% were diabetics, half had MS and 76% presented echographic hepatic steatosis. In multivariate analyses, fatty liver and MS were associated with carotid atherosclerosis [odds ratio (95% confidence intervals) 2.15 (1.27-3.63) and 1.72(1.12-2.64), respectively], whereas HOMA index was not. Aspartate aminotransferase and alanine aminotransferase were not independently associated with carotid atherosclerosis, whereas gamma-glutamyl transferase showed a link with atherosclerosis beyond MS and steatosis presence. The analyses of the 780 non diabetics recruited showed similar results.

CONCLUSIONS

The results of the present study demonstrate that hepatic steatosis measured by echography is associated with carotid atherosclerosis in a large population mostly carrying cardiovascular or metabolic risk factors, independently of MS, cardiovascular diseases, diabetes mellitus and/or insulin resistance.

Elevated alanine aminotransferase levels predict mortality from cardiovascular disease and diabetes in Koreans

OBJECTIVE

Metabolic syndrome is associated with increased cardiovascular morbidity and mortality. Nonalcoholic fatty liver disease (NAFLD) is closely associated with metabolic syndrome. This study investigated the relationship between elevated alanine aminotransferase (ALT) levels, as a proxy marker of NAFLD, and death from cardiovascular disease (CVD) or diabetes in a Korean population.

METHODS

The study population consisted of 37,085 patients who underwent health examinations at the Health Promotion Center of the Asan Medical Center, Seoul, Korea, in 2000 and 2001. Individuals with viral hepatitis or alcoholic liver disease were excluded from the study. The relationship between baseline ALT levels and CVD- or diabetes-related mortality was determined for a median period of 5.0 years.

RESULTS

A total of 407 deaths occurred during the follow-up period, with 91 deaths resulting from CVD or diabetes. The multivariate relative risk (RR) and 95% confidence interval (CI) for CVD- or diabetes-related mortality in patients with ALT levels >40IU/L were 2.26 (1.22-4.19). The multivariate RR and 95% CI for CVD- or diabetes-related mortality in patients with the highest quartile of ALT levels (> or =31IU/L) were 2.28 (95% CI: 1.02-5.08) when the lowest quartile (< or =15IU/L) was used as a reference.

CONCLUSION

Our findings demonstrate that elevated ALT levels are independently associated with increased CVD- or diabetes-related mortality in Koreans. Thus, elevated ALT levels, as a marker for NAFLD, may serve as a surrogate predictor of CVD- or diabetes-related mortality among the Korean population.

The metabolic syndrome

The "metabolic syndrome" (MetS) is a clustering of components that reflect overnutrition, sedentary lifestyles, and resultant excess adiposity. The MetS includes the clustering of abdominal obesity, insulin resistance, dyslipidemia, and elevated blood pressure and is associated with other comorbidities including the prothrombotic state, proinflammatory state, nonalcoholic fatty liver disease, and reproductive disorders. Because the MetS is a cluster of different conditions, and not a single disease, the development of multiple concurrent definitions has resulted. The prevalence of the MetS is increasing to epidemic proportions not only in the United States and the remainder of the urbanized world but also in developing nations. Most studies show that the MetS is associated with an approximate doubling of cardiovascular disease risk and a 5-fold increased risk for incident type 2 diabetes mellitus. Although it is unclear whether there is a unifying pathophysiological mechanism resulting in the MetS, abdominal adiposity and insulin resistance appear to be central to the MetS and its individual components. Lifestyle modification and weight loss should, therefore, be at the core of treating or preventing the MetS and its components. In addition, there is a general consensus that other cardiac risk factors should be aggressively managed in individuals with the MetS. Finally, in 2008 the MetS is an evolving concept that continues to be data driven and evidence based with revisions forthcoming.

Metabolic syndrome as a risk factor for nonalcoholic fatty liver disease

BACKGROUND

Metabolic syndrome has been linked to nonalcoholic fatty liver disease (NAFLD).

OBJECTIVES

The purpose of the current study was to evaluate metabolic syndrome as a risk factor for NAFLD in Taiwanese adults.

METHODS

A cross-sectional study was conducted in which 876 subjects were enrolled. The diagnosis of NAFLD was made by abdominal ultrasonography. The Asia-Pacific modification of the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III guidelines was used to establish the diagnosis of metabolic syndrome.

RESULTS

NAFLD was diagnosed in 373 (42.6%) of the study population. Metabolic syndrome was diagnosed in 202 (23.1%) of the study population, and it was independently associated with NAFLD (odds ratio [OR] = 2.37; P < 0.001). Among the components of metabolic syndrome, hypertriglyceridemia (OR = 2.24; P < 0.001), hyperglycemia (OR = 2.23; P = 0.001), increased waist circumference (OR = 1.76; P = 0.013), and the diagnostic components of metabolic syndrome were independently associated with NAFLD.

CONCLUSION

Metabolic syndrome and some of its diagnostic components are independent risk factors for NAFLD.

Severe liver steatosis correlates with nitrosative and oxidative stress in rats

BACKGROUND

Little is known about nitric oxide (NO) metabolism and redox changes with hepatocyte adipocytic transformation. The aims of this study were to investigate the changes occurring in plasma and hepatic NO metabolites and redox balance in a rat experimental model of simple fatty liver, and to relate plasma with hepatic and mitochondrial changes at different degrees of steatosis.

MATERIALS AND METHODS

Circulating and hepatic redox active and nitrogen regulating molecules thioredoxin, glutathione, protein thiols (PSH), mixed disulfides (PSSG), NO metabolites nitrosothiols, nitrite plus nitrate (NOx), and lipid peroxides (TBARs) were measured in rats fed a choline deprived (CD) diet for 30 days.

RESULTS

At histology, the CD diet resulted in hepatocellular steatosis (75% of liver weight at day 30) with no signs of necro-inflammation. In plasma, thioredoxin, nitrosothiols and NOx were unchanged, while TBARs levels increased significantly and were positively related with hepatic TBARs (r = 0.87, P < 0.001) and lipid content (r = 0.90, P < 0.001). In the liver, glutathione initially increased (day 3) and then decreased. From day 14, PSH decreased and NO derivatives increased. Thioredoxin 1 had initially increased (days 7-14) and then decreased. In the mitochondria, on day 14, nitrosothiols were inversely related to thioredoxin 2 (r = 0.988, P < 0.05); on day 30, PSH were decreased by 70%, PSSG were doubled and related with nitrosothiols levels (r = 0.925, P < 0.001).

CONCLUSION

Adipocytic transformation of hepatocytes is accompanied by major interrelated modifications of redox parameters and NO metabolism especially at mitochondrial level, suggesting an early adaptive protective response but also an increased predisposition towards pro-oxidant insults.

Should nonalcoholic fatty liver disease be included in the definition of metabolic syndrome? A cross-sectional comparison with Adult Treatment Panel III criteria in nonobese nondiabetic subjects

OBJECTIVE

The ability of the Adult Treatment Panel III (ATP III) criteria of metabolic syndrome to identify insulin-resistant subjects at increased cardiovascular risk is suboptimal, especially in the absence of obesity and diabetes. Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance and is emerging as an independent cardiovascular risk factor. We compared the strength of the associations of ATP III criteria and of NAFLD to insulin resistance, oxidative stress, and endothelial dysfunction in nonobese nondiabetic subjects.

RESEARCH DESIGN AND METHODS

Homeostasis model assessment of insulin resistance (HOMA-IR) >2, oxidative stress (nitrotyrosine), soluble adhesion molecules (intracellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin), and circulating adipokines (tumor necrosis factor-alpha, leptin, adiponectin, and resistin) were cross-sectionally correlated to ATP III criteria and to NAFLD in 197 unselected nonobese nondiabetic subjects.

RESULTS

NAFLD more accurately predicted insulin resistance than ATP III criteria: sensitivity 73 vs. 38% (P = 0.0001); positive predictive value: 81 vs. 62% (P = 0.035); negative predictive value 87 vs. 74% (P = 0.012); positive likelihood ratio 4.39 vs. 1.64 (P = 0.0001); and negative likelihood ratio 0.14 vs. 0.35 (P = 0.0001). Adding NAFLD to ATP III criteria significantly improved their diagnostic accuracy for insulin resistance. Furthermore, NAFLD independently predicted HOMA-IR, nitrotyrosine, and soluble adhesion molecules on logistic regression analysis; the presence of NAFLD entailed more severe oxidative stress and endothelial dysfunction, independent of adiposity or any feature of the metabolic syndrome in insulin-resistant subjects.

CONCLUSIONS

NAFLD is more tightly associated with insulin resistance and with markers of oxidative stress and endothelial dysfunction than with ATP III criteria in nonobese nondiabetic subjects and may help identify individuals with increased cardiometabolic risk in this population.

Hepatic steatosis and increased adiposity in mice consuming rapidly vs. slowly absorbed carbohydrate

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is fast becoming a major public health concern, coincident with the increasing prevalence of obesity. Although lifestyle greatly influences development of NAFLD, the specific dietary causes remain largely unknown. The purpose of this study was to determine whether a diet high in rapidly absorbed carbohydrate (RAC) vs. slowly absorbed carbohydrate (SAC), controlled for confounding dietary factors, causes NAFLD in mice with similar body weight. An animal model was chosen because of logistical and ethical challenges to conducting this study in humans.

RESEARCH METHODS AND PROCEDURES

Male 129SvPas mice were fed diets high in either RAC (amylopectin; high glycemic index) or SAC (amylose; low glycemic index) for 25 weeks. Diets were controlled for macronutrient and micronutrient content, differing only in starch type. Body weight and composition were measured throughout the study. Hepatic and plasma triacylglycerol concentrations were quantified at the end of the study.

RESULTS

Body weight was not significantly different between the two groups. However, total body adiposity increased twice as much, in absolute terms, in the mice fed RAC vs. SAC (12.2 +/- 2.9% vs. 6.1 +/- 4.2%, p < 0.0001). Hepatic triacylglycerol content was 2-fold greater in the RAC group (20.7 +/- 9.4 vs. 9.6 +/- 4.9 mg/g, p = 0.01). In addition, plasma insulin and triacylglycerol concentrations were higher in the RAC group.

DISCUSSION

A diet high in RAC causes accumulation of fat in liver, adipose tissue, and plasma in mice. Therefore, a low glycemic index diet may help prevent or treat NAFLD in humans.

Ultrasonographic evaluation of liver volume and the metabolic syndrome in obese women

Non-alcoholic fatty liver disease is a common finding in obese subjects, and increasing evidence has been provided suggesting that it represents the hepatic component of the metabolic syndrome. The aim of this study was to evaluate whether the extent of liver enlargement is related to the severity of the metabolic syndrome in obese women. The relationship between ultrasound- measured hepatic left lobe volume (HLLV) and various features of the metabolic syndrome was evaluated in 85 obese women. The mean+/-SD value of HLLV in obese women was 431+/-214 ml (range 46-1019 ml) while it was 187+/-31 ml (range 143-258 ml) in lean subjects. In a multiple logistic regression analysis, ultrasound-measured intra-abdominal fat was the only anthropometric measure independently associated with HLLV. A strong positive association was found between HLLV and serum liver enzymes, triglycerides, glucose, insulin, uric acid, C reactive protein, systolic and diastolic blood pressure, while a negative correlation was observed between HLLV and HDL cholesterol. The values of HLLV corresponding to the cut-off values of various risk factors for the diagnosis of the metabolic syndrome were calculated, yielding a mean value of 465 ml. In conclusion, ultrasound measurement of HLLV represents a simple, reliable and low-cost tool for the evaluation of liver involvement in the metabolic syndrome. The strong association between liver enlargement and various cardiovascular risk factors associated with insulin resistance supports the role of liver steatosis as an important link among the many facets of the metabolic syndrome in human obesity.

Hepatitis C infection and diabetes

Since the discovery of the hepatitis C virus (HCV) in 1989, attention has been paid to the association of chronic HCV infection and the development of diabetes. The risk factors for diabetes include older age, HCV genotype 3, severe liver fibrosis, family history of diabetes, and liver/kidney transplantation. Emerging evidence in animals and humans has shown that HCV infection induces hepatic steatosis and increases tumor necrosis factor-alpha level, both resulting in the development of insulin resistance and subsequent type 2 diabetes. It is suggested that the presence of diabetes and hepatic steatosis may enhance fibrosis progression, hepatocellular carcinoma, and atherosclerosis. Interferon is reportedly associated with improved glucose tolerance. However, interferon might enhance underlying autoimmunity against beta cells, leading to overt type 1 diabetes that is genetically predisposed or give rise to hyperglycemia, resulting in the development of type 2 diabetes. In light of the national epidemic of type 2 diabetes, the link between HCV and diabetes would be a major public health problem. Further clinical researches are awaited in order to effectively detect, prevent, and treat HCV-associated type 2 diabetes, which would also slow the progression of hepatitis C itself.

Adipokines in NASH: postprandial lipid metabolism as a link between adiponectin and liver disease

Circulating levels of four adipokines (adiponectin, TNF-alpha, leptin, and resistin) and the postprandial lipid and adiponectin responses to an oral fat load were assessed in 25 non-obese, non-diabetic patients with biopsy-proven nonalcoholic steatohepatitis (NASH) and correlated with metabolic indices and liver histology. Circulating adiponectin was lower in NASH compared with controls (5,476 +/- 344 vs. 11,548 +/- 836 ng/mL; P = .00001) and on multiple regression analysis correlated negatively with liver steatosis, necroinflammation (OR = 5.0; P = .009), and fibrosis (OR = 8.0; P = .003). The magnitude of postprandial lipemia was significantly higher in NASH than in controls and was related to fasting adiponectin (beta = -0.78; P = .00003). Controls showed a significant increase in serum adiponectin in response to the fat load, whereas patients with NASH showed a slight decrease. Postprandial free fatty acids response correlated inversely with adiponectin response in both groups and independently predicted the severity of liver steatosis in NASH (beta = 0.51; P = .031). In conclusion, hypoadiponectinemia is present before overt diabetes and obesity appear and correlates with the severity of liver histology in NASH. Impaired postprandial lipid metabolism may be an additional mechanism linking hypoadiponectinemia and NASH and posing a higher cardiovascular risk to these subjects. The mechanism(s) underlying these differences are unknown, but the type of dietary fat seems to play a role. These findings may have important pathogenetic and therapeutic implications in both liver and metabolic disease.