| 1. |
- Hyysalo, Jenni, et al.
(författare)
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Genetic variation in PNPLA3 but not APOC3 influences liver fat in non-alcoholic fatty liver disease
- 2012
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Ingår i: Journal of Gastroenterology and Hepatology. - : Wiley. - 0815-9319. ; 27:5, s. 951-956
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aim: A recent study in Indian subjects suggested common variants in apolipoprotein C3 (APOC3) (T-455C at rs2854116 and C-482T at rs2854117) to contribute to non-alcoholic fatty liver disease (NAFLD), plasma apoC3 and triglyceride concentrations. Our aim was to determine the contribution of genetic variation in APOC3 on liver fat content and plasma triglyceride and apoC3 concentrations in a larger European cohort. Methods: Atotal of 417 Finnish individuals were genotyped for rs2854116 and rs2854117 in APOC3 and the known rs738409 in patatin-like phospholipase domain-containing protein 3 (PNPLA3) influencing liver fat. Plasma apoC3 concentration was measured enzymatically, and liver fat by proton magnetic resonance spectroscopy. Results: APOC3 wild-type homozygotes and variant allele (T-455C or C-482T or both) carriers did not differ with regard to liver fat, apoC3 concentrations, triglyceride-, high density lipoprotein-, fasting plasma glucose, insulin-, alanine aminotransferase-and aspartate aminotransferase-concentrations, nor was there a difference in prevalence of NAFLD. In contrast, carriers of the PNPLA3 GG genotype at rs738409 had a 2.7-fold (median 11.3%) higher liver fat than those with the CC (median 4.2%) genotype. The PNPLA3 rs738409 was also an independent predictor of liver fat, together with age, gender, and body mass index. Conclusion: Genetic variants in PNPLA3 but not APOC3 contribute to the variance in liver fat content due to NAFLD.
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| 2. |
- Kotronen, Anna, et al.
(författare)
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Prediction of Non-Alcoholic Fatty Liver Disease and Liver Fat Using Metabolic and Genetic Factors
- 2009
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Ingår i: Gastroenterology. - : Elsevier BV. - 1528-0012 .- 0016-5085. ; 137:3, s. 865-872
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Our aims were to develop a method to accurately predict non-alcoholic fatty liver disease (NAFLD) and liver fat content based on routinely available clinical and laboratory data and to test whether knowledge of the recently discovered genetic variant in the PNPLA3 gene (rs738409) increases accuracy of the prediction. METHODS: Liver fat content was measured using proton magnetic resonance spectroscopy in 470 subjects, who were randomly divided into estimation (two thirds of the subjects, n = 313) and validation (one third of the subjects, n = 157) groups. Multivariate logistic and linear regression analyses were used to create an NAFLD liver fat score to diagnose NAFLD and liver fat equation to estimate liver fat percentage in each individual. RESULTS: The presence of the metabolic syndrome and type 2 diabetes, fasting serum (fS) insulin, FS-aspartate aminotransferase (AST), and the AST/alanine aminotransferase ratio were independent predictors of NAFLD. The score had an area under the receiver operating characteristic curve of 0.87 in the estimation and 0.86 in the validation group. The optimal cut-off point of -0.640 predicted increased liver fat content with sensitivity of 86% and specificity of 71%. Addition of the genetic information to the score improved the accuracy of the prediction by only <1%. Using the same variables, we developed a liver fat equation from which liver fat percentage of each individual could be estimated. CONCLUSIONS: The NAFLD liver fat score and liver fat equation provide simple and noninvasive tools to predict NAFLD and liver fat content.
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| 3. |
- Llaurado, Gemma, et al.
(författare)
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Liver Fat Content and Hepatic Insulin Sensitivity in Overweight Patients With Type 1 Diabetes
- 2015
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 100:2, s. 607-616
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Patients with type 1 diabetes mellitus (T1DM) lack the portal/peripheral insulin gradient, which might diminish insulin stimulation of hepatic lipogenesis and protect against development of nonalcoholic fatty liver disease (NAFLD). We compared liver fat content and insulin sensitivity of hepatic glucose production and lipolysis between overweight T1DM patients and nondiabetic subjects. Materials and Methods: We compared 32 overweight adult T1DM patients and 32 nondiabetic subjects matched for age, body mass index (BMI), and gender. Liver fat content was measured using proton magnetic resonance spectroscopy (H-1-MRS), body composition by magnetic resonance imaging, and insulin sensitivity using the euglycemic-hyperinsulinemic clamp technique (insulin 0.4 mU/kg.min combined with infusion of D-[3-H-3] glucose). We also hypothesized that low liver fat might protect from obesity-associated increases in insulin requirements and, therefore, determined insulin requirements across BMI categories in 3164 T1DM patients. Results: Liver fat content was significantly lower in T1DM patients than in nondiabetic subjects (0.6% [25th-75th quartiles, 0.3%-1.1%] vs 9.0% [ 3.0%-18.0%]; P<.001). The endogenous rate of glucose production (R-a) during euglycemic hyperinsulinemia was significantly lower (0.4 [-0.7 to 0.8] mg/kg fat-free mass.min vs 0.9 [0.2-1.6] fat-free mass.min; P=.012) and the percent suppression of endogenous R-a by insulin was significantly greater (89% [78%-112%] vs 77% [50%-94%]; p=.009) in T1DM patients than in nondiabetic subjects. Serum nonesterified fatty acid concentrations during euglycemic hyperinsulinemia were significantly lower (78.5 [33.0-155.0] vs 306 [200.0-438.0] mu mol/L; P<.001) and the percent suppression of nonesterified fatty acids significantly higher (89.1% [78.6%-93.3%] vs 51.4% [36.5%-71.1%]; P<.001) in T1DM patients than in nondiabetic subjects. Insulin doses were similar across BMI categories. Conclusions: T1DM patients might be protected from steatosis and hepatic insulin resistance. Obesity may not increase insulin requirements in T1DM.
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| 4. |
- Petaja, Elina M., et al.
(författare)
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Adipocyte Size is Associated with NAFLD Independent of Obesity, Fat Distribution, and PNPLA3 Genotype
- 2013
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Ingår i: Obesity. - : Wiley. - 1930-739X .- 1930-7381. ; 21:6, s. 1174-1179
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Adipocyte hypertrophy has been suggested to be causally linked with inflammation and systemic insulin resistance. The aim of the study was to determine whether increased adipocyte size is associated with increased liver fat content due to nonalcoholic fatty liver disease (NAFLD) in humans independent of obesity, fat distribution and genetic variation in the patatin-like phospholipase domain-containing 3 gene (PNPLA3; adiponutrin) at rs738409. Design and Methods: One hundred nineteen non-diabetic subjects in a cross-sectional study with a median age of 39 (26-53) years, mean +/- SD BMI of 30.0 +/- 5.7 kg m(-2) were studied. Abdominal subcutaneous (SC) adipocyte size, liver fat [proton magnetic resonance spectroscopy (H-1-MRS)], intra-abdominal (IA), and abdominal SC adipose tissue volumes [magnetic resonance imaging (MRI)] and the PNPLA3 genotype at rs738409 were determined. Univariate and multiple linear regression analysis were used to identify independent predictors of liver fat content. Results: In multiple linear regression analysis, age, gender, BMI, the IA/SC ratio, and PNPLA3 genotype explained 42% of variation in liver fat content. Addition of adipocyte size (P < 0.0001) to the model increased the percent of explanation to 53%. Thus, 21% of known variation in liver fat could be explained by adipocyte size alone. Conclusions:: Increased adipocyte size highly significantly contributes to liver fat accumulation independent of other causes.
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| 5. |
- Sevastianova, Ksenia, et al.
(författare)
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Genetic variation in PNPLA3 (adiponutrin) confers sensitivity to weight loss-induced decrease in liver fat in humans
- 2011
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 1938-3207 .- 0002-9165. ; 94:1, s. 104-111
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Tidskriftsartikel (refereegranskat)abstract
- Background: The rs738409 C -> G single nucleotide polymorphism in the patatin-like phospholipase domain-containing 3 (PNPLA3; adiponutrin) leads to a missense mutation (I148M), which is associated with increased liver fat but not insulin resistance. The I148M mutation impedes triglyceride hydrolysis in vitro, and its carriers have an increased risk of developing severe liver disease. Objective: We explored whether the rs738409 PNPLA3 G allele influences the ability of weight loss to decrease liver fat or change insulin sensitivity. Design: We recruited 8 subjects who were homozygous for the rs738409 PNPLA3 G allele (PNPLA3-148MM) and 10 who were homozygous for the rs738409 PNPLA3 C allele (PNPLA3-148II). To allow comparison of changes in liver fat, the groups were matched with respect to baseline age, sex, body mass index, and liver fat. The subjects were placed on a hypocaloric low-carbohydrate diet for 6 d. Liver fat content (proton magnetic resonance spectroscopy), whole-body insulin sensitivity of glucose metabolism (euglycemic clamp technique), and lipolysis ([H-2(5)] glycerol infusion) were measured before and after the diet. Results: At baseline, fasting serum insulin and C-peptide concentrations were significantly lower in the PNPLA3-148MM group than in the PNPLA3-148II group, as predicted by study design. Weight loss was not significantly different between groups (PNPLA3-148MM: -3.1 +/- 0.5 kg; PNPLA3-148II: -3.1 +/- 0.4 kg). Liver fat decreased by 45% in the PNPLA3-148MM group (P < 0.001) and by 18% in the PNPLA3-148II group (P < 0.01). Conclusion: Weight loss is effective in decreasing liver fat in subjects who are homozygous for the rs738409 PNPLA3 G or C allele. This trial was registered at www.hus.fi as 233775. Am J Clin Nutr 2011;94:104-11.
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| 6. |
- Suomalainen, Anu, et al.
(författare)
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FGF-21 as a biomarker for muscle-manifesting mitochondrial respiratory chain deficiencies: a diagnostic study.
- 2011
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Ingår i: Lancet neurology. - 1474-4465. ; 10:9, s. 806-818
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Muscle biopsy is the gold standard for diagnosis of mitochondrial disorders because of the lack of sensitive biomarkers in serum. Fibroblast growth factor 21 (FGF-21) is a growth factor with regulatory roles in lipid metabolism and the starvation response, and concentrations are raised in skeletal muscle and serum in mice with mitochondrial respiratory chain deficiencies. We investigated in a retrospective diagnostic study whether FGF-21 could be a biomarker for human mitochondrial disorders. METHODS: We assessed samples from adults and children with mitochondrial disorders or non-mitochondrial neurological disorders (disease controls) from seven study centres in Europe and the USA, and recruited healthy volunteers (healthy controls), matched for age where possible, from the same centres. We used ELISA to measure FGF-21 concentrations in serum or plasma samples (abnormal values were defined as >200 pg/mL). We compared these concentrations with values for lactate, pyruvate, lactate-to-pyruvate ratio, and creatine kinase in serum or plasma and calculated sensitivity, specificity, and positive and negative predictive values for all biomarkers. FINDINGS: We analysed serum or plasma from 67 patients (41 adults and 26 children) with mitochondrial disorders, 34 disease controls (22 adults and 12 children), and 74 healthy controls. Mean FGF-21 concentrations in serum were 820 (SD 1151) pg/mL in adult and 1983 (1550) pg/mL in child patients with respiratory chain deficiencies and 76 (58) pg/mL in healthy controls. FGF-21 concentrations were high in patients with mitochondrial disorders affecting skeletal muscle but not in disease controls, including those with dystrophies. In patients with abnormal FGF-21 concentrations in serum, the odds ratio of having a muscle-manifesting mitochondrial disease was 132·0 (95% CI 38·7-450·3). For the identification of muscle-manifesting mitochondrial disease, the sensitivity was 92·3% (95% CI 81·5-97·9%) and specificity was 91·7% (84·8-96·1%). The positive and negative predictive values for FGF-21 were 84·2% (95% CI 72·1-92·5%) and 96·1 (90·4-98·9%). The accuracy of FGF-21 to correctly identify muscle-manifesting respiratory chain disorders was better than that for all conventional biomarkers. The area under the receiver-operating-characteristic curve for FGF-21 was 0·95; by comparison, the values for other biomarkers were 0·83 lactate (p=0·037, 0·83 for pyruvate (p=0·015), 0·72 for the lactate-to-pyruvate ratio (p=0·0002), and 0·77 for creatine kinase (p=0·013). INTERPRETATION: Measurement of FGF-21 concentrations in serum identified primary muscle-manifesting respiratory chain deficiencies in adults and children and might be feasible as a first-line diagnostic test for these disorders to reduce the need for muscle biopsy. FUNDING: Sigrid Jusélius Foundation, Jane and Aatos Erkko Foundation, Molecular Medicine Institute of Finland, University of Helsinki, Helsinki University Central Hospital, Academy of Finland, Novo Nordisk, Arvo and Lea Ylppö Foundation.
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