Metabolic syndrome:A review of the role of vitamin D in mediating susceptibility and outcome

Despite the well-recognised role of vitamin D in a wide range of physiological processes,hypovitaminosis is common worldwide(prevalence 30%-50%) presumably arising from inadequate exposure to ultraviolet radiation and insufficient consumption.While generally not at the very low levels associated with rickets,hypovitaminosis D has been implicated in various very different,pathophysiological processes.These include putative effects on the pathogenesis of neoplastic change,inflammatory and demyelinating conditions,cardiovascular disease(CVD) and diabetes.This review focuses on the association between hypovitaminosis D and the metabolic syndrome as well as its component characteristics which are central obesity,glucose homeostasis,insulin resistance,hypertension and atherogenic dyslipidaemia.We also consider the effects of hypovitaminosis D on outcomes associated with the metabolic syndrome such as CVD,diabetes and non-alcoholic fatty liver disease.We structure this review into 3 distinct sections; the metabolic syndrome,vitamin D biochemistry and the putative association between hypovitaminosis D,the metabolic syndrome and cardiovascular risk.

Female spontaneously diabetic Torii fatty rats develop nonalcoholic steatohepatitis-like hepatic lesions

AIM:To investigate the histological features of the liver in spontaneously diabetic Torii(SDT) fatty rats compared with age-matched Sprague-Dawley(SD) rats.METHODS:Female SDT Leprfa(SDT fatty) rats and age-matched SD rats were fed ad libitum. Body weight and biochemical parameters,such as serum glucose,triglyceride(TG),total cholesterol(TC),alanine aminotransferase(ALT) and aspartate aminotransferase(AST) levels as well as fatty acid and TG accumulation in the liver were evaluated at 8 wk of age in the nonfasting state and at 8-wk intervals from 8 to 40 wk of age. Histopathological examinations of the liver were performed using hematoxylin and eosin and Sirius Red staining as well as double staining for ED-1 and toluidine blue. The expression of genes involved in TG synthesis,inflammation,and fibrosis was examined in the liver.RESULTS:SDT fatty rats showed significantly increased body weight compared with SD rats. Serum glucose,TG,and TC levels were significantly higher in SDT fatty rats compared with SD rats. The serum AST and ALT levels in SDT fatty rats were significantly elevated at 8 wk of age compared with the levels in SD rats. Hepatic TG content was marked in SDT fatty rats from 8 to 32 wk of age. Histopathologically,severe hepatosteatosis accompanied by inflammation was observed at 8 wk of age,and fibrosis started to occur at 32 wk of age. Furthermore,Sirius Red and ED-1 staining were increased in the liver at 32 wk of age. Hepatic gene expression related to TG synthesis,inflammation and fibrosis tended to increase in SDT fatty rats compared with SD rats,and the gene expression related to TG secretion was decreased in SDT fatty rats compared with SD rats. CONCLUSION:Female SDT fatty rats have the potential to become an important animal model of nonalcoholic steatohepatitis with type 2 diabetes and obesity.

Increased serum soluble lectin-like oxidized low-density lipoprotein receptor-1 levels in patients with biopsy-proven nonalcoholic fatty liver disease

AIM: To analyze the relationship between the serum lectin-like oxidized low-density lipoprotein receptor-1(LOX-1) levels and clinical and histopathological features of biopsy-confirmed nonalcoholic fatty liver disease(NAFLD) patients.METHODS: Fifty-three consecutive,biopsy-proven NAFLD patients(31 males and 22 females,mean age 42.5 ± 9.6 years) and 26 age- and gender-matched,healthy controls(14 males and 12 females,mean age 39 ± 10.7 years) were included.The patientswith NAFLD were consecutive patients who had been admitted to the hepatology outpatient clinic within the last year and had been diagnosed with NAFLD as the result of liver biopsy.The healthy controls were individuals who attended the outpatient clinic for routine health control and had no known chronic illnesses.The histological evaluation was conducted according t o t he N AF LD ac t ivi ty scoring syst em recommended by The National Institute of Diabetes and Digestive and Kidney Diseases Nonalcoholic Steatohepatitis Clinical Research Network.The serum LOX-1 levels were measured using an ELISA kit(Life Science Inc.USCN.Wuhan,Catalog No.E1859Hu) in both patients and healthy controls.A receiver operating characteristic(ROC) curve analysis was used to identify the optimal cutoff value of LOX-1 and thereby distinguish between patients with nonalcoholic steatohepatitis(NASH) and healthy controls.A P-value < 0.05 was considered statistically significant.RESULTS: NAFLD and healthy control groups were similar in terms of age and sex.NAFLD patients consisted of 8 patients with simple steatosis(15%),27 with borderline NASH(51%) and 18 with definitive NASH(34%).Metabolic syndrome was found in 62.2% of the patients with NAFLD.The mean serum LOX-1 level in biopsy-proven NAFLD patients was 8.49 ± 6.43 ng/m L compared to 4.08 ± 4.32 ng/m L in healthy controls(P = 0.001).The LOX-1 levels were significantly different between controls,simple steatosis and NASH(borderline+definite) cases(4.08 ± 4.32 ng/m L,6.1 ± 6.16 ng/m L,8.92 ± 6.45 ng/m L,respectively,P = 0.004).When the cut-off value for the serum LOX-1 level was set at 5.35 ng/m L,and a ROC curve analysis was performed to distinguish between steatohepatitis patients and controls; the sensitivity and specificity of the serum LOX-1 level were 69.8% and 69.2%,respectively.CONCLUSION: The serum LOX-1 levels were significantly higher in NAFLD patients than in healthy controls.Additionally,the serum LOX-1 levels could differentiate between steatohepatitis patients and healthy controls.

Non-alcoholic fatty liver disease and beneficial effects of dietary supplements

I read with great interest the review published by Eslamparast et al, on the dietary supplements with hepato-protective properties, and their proposed mechanisms to protect against non-alcoholic fatty liver disease. In this way, recently, our study group reported the efficacy of the Mediterranean diet associated to an antioxidant complex, to improve in overweight patientsnot only anthropometric parameters, but also insulinresistance, lipid serum levels, and intra-hepatic fat accumulation.

Non-alcoholic fatty liver disease: What the clinician needs to know

Non-alcoholic fatty liver disease(NAFLD) is the most frequent cause of liver disease in the Western world. Furthermore, it is increasing worldwide, paralleling the obesity pandemic. Though highly frequent, only about one fifth of affected subjects are at risk of developing the progressive form of the disease, non-alcoholic steatohepatitis with fibrosis. Even in the latter, liver disease is slowly progressive, though, since it is so prevalent, it is already the third cause of liver transplantation in the United States, and it is predicted to get to the top of the ranking in few years. Of relevance, fatty liver is also associated with increased overall mortality and particularly increased cardiovascular mortality. The literature and amount of published papers on NAFLD is increasing as fast as its prevalence, which makes it difficult to keep updated in this topic. This review aims to summarize the latest knowledge on NAFLD, in order to help clinicians understanding its pathogenesis and advances on diagnosis and treatment.