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1.  DEPDC5 variants increase fibrosis progression in Europeans with chronic hepatitis C virus infection 
Hepatology (Baltimore, Md.)  2015;63(2):418-427.
Chronic hepatitis C virus (HCV) infection may progress to cirrhosis and hepatocellular carcinoma (HCC). Recently, two genetic variants, DEPDC5 rs1012068 and MICA rs2596542, were associated with the onset of HCC in Asian subjects with chronic HCV infection. The aim of the present study was to analyze whether DEPDC5 and MICA genetic variants were associated with liver disease progression in European subjects with chronic HCV infection. In a Northern Italian discovery cohort (n = 477), neither DEPDC5 rs1012068 nor MICA rs2596542 were associated with HCC (n = 150). However, DEPDC5 rs1012068 was independently associated with cirrhosis (n = 300; P = 0.049). The association of rs1012068 with moderate to severe fibrosis was confirmed in an independent cross‐sectional German cohort (n = 415; P = 0.006). Furthermore, DEPDC5 rs1012068 predicted faster fibrosis progression in a prospective cohort (n = 247; P = 0.027). Next, we examined the distribution of nonsynonymous DEPDC5 variants in the overall cross‐sectional cohort (n = 912). The presence of at least one variant increased the risk of moderate/severe fibrosis by 54% (P = 0.040). To understand the molecular mechanism underlying the genetic association of DEPDC5 variants with fibrosis progression, we performed in vitro studies on immortalized hepatic stellate cells (LX‐2). In these cells, down‐regulation of DEPDC5 resulted in increased expression of β‐catenin and production of its target matrix metallopeptidase 2 (MMP2), a secreted enzyme involved in fibrosis progression. Conclusion: DEPDC5 variants increase fibrosis progression in European subjects with chronic HCV infection. Our findings suggest that DEPDC5 down‐regulation may contribute to HCV‐related fibrosis by increasing MMP2 synthesis through the β‐catenin pathway. (Hepatology 2016;63:418–427)
PMCID: PMC4737289  PMID: 26517016
2.  The androgen receptor confers protection against diet-induced atherosclerosis, obesity, and dyslipidemia in female mice 
The FASEB Journal  2014;29(4):1540-1550.
Androgens have important cardiometabolic actions in males, but their metabolic role in females is unclear. To determine the physiologic androgen receptor (AR)–dependent actions of androgens on atherogenesis in female mice, we generated female AR-knockout (ARKO) mice on an atherosclerosis-prone apolipoprotein E (apoE)–deficient background. After 8 weeks on a high-fat diet, but not on a normal chow diet, atherosclerosis in aorta was increased in ARKO females (+59% vs. control apoE-deficient mice with intact AR gene). They also displayed increased body weight (+18%), body fat percentage (+62%), and hepatic triglyceride levels, reduced insulin sensitivity, and a marked atherogenic dyslipidemia (serum cholesterol, +52%). Differences in atherosclerosis, body weight, and lipid levels between ARKO and control mice were abolished in mice that were ovariectomized before puberty, consistent with a protective action of ovarian androgens mediated via the AR. Furthermore, the AR agonist dihydrotestosterone reduced atherosclerosis (−41%; thoracic aorta), subcutaneous fat mass (−44%), and cholesterol levels (−35%) in ovariectomized mice, reduced hepatocyte lipid accumulation in hepatoma cells in vitro, and regulated mRNA expression of hepatic genes pivotal for lipid homeostasis. In conclusion, we demonstrate that the AR protects against diet-induced atherosclerosis in female mice and propose that this is mediated by modulation of body composition and lipid metabolism.—Fagman, J. B., Wilhelmson, A. S., Motta, B. M., Pirazzi, C., Alexanderson, C., De Gendt, K., Verhoeven, G., Holmäng, A., Anesten, F., Jansson, J.-O., Levin, M., Borén, J., Ohlsson, C., Krettek, A., Romeo, S., Tivesten, A. The androgen receptor confers protection against diet-induced atherosclerosis, obesity, and dyslipidemia in female mice.
PMCID: PMC4470404  PMID: 25550469
genetically altered mice; metabolism; sex hormones
3.  PNPLA3 has retinyl-palmitate lipase activity in human hepatic stellate cells 
Human Molecular Genetics  2014;23(15):4077-4085.
Retinoids are micronutrients that are stored as retinyl esters in the retina and hepatic stellate cells (HSCs). HSCs are key players in fibrogenesis in chronic liver diseases. The enzyme responsible for hydrolysis and release of retinyl esters from HSCs is unknown and the relationship between retinoid metabolism and liver disease remains unclear. We hypothesize that the patatin-like phospholipase domain-containing 3 (PNPLA3) protein is involved in retinol metabolism in HSCs. We tested our hypothesis both in primary human HSCs and in a human cohort of subjects with non-alcoholic fatty liver disease (N = 146). Here we show that PNPLA3 is highly expressed in human HSCs. Its expression is regulated by retinol availability and insulin, and increased PNPLA3 expression results in reduced lipid droplet content. PNPLA3 promotes extracellular release of retinol from HSCs in response to insulin. We also show that purified wild-type PNPLA3 hydrolyzes retinyl palmitate into retinol and palmitic acid. Conversely, this enzymatic activity is markedly reduced with purified PNPLA3 148M, a common mutation robustly associated with liver fibrosis and hepatocellular carcinoma development. We also find the PNPLA3 I148M genotype to be an independent (P = 0.009 in a multivariate analysis) determinant of circulating retinol-binding protein 4, a reliable proxy for retinol levels in humans. This study identifies PNPLA3 as a lipase responsible for retinyl-palmitate hydrolysis in HSCs in humans. Importantly, this indicates a potential novel link between HSCs, retinoid metabolism and PNPLA3 in determining the susceptibility to chronic liver disease.
PMCID: PMC4082369  PMID: 24670599
4.  Cardiovascular Events After Bariatric Surgery in Obese Subjects With Type 2 Diabetes 
Diabetes Care  2012;35(12):2613-2617.
Obese individuals with type 2 diabetes have an increased risk of cardiovascular disease. The effect of bariatric surgery on cardiovascular events in obese individuals with type 2 diabetes remains to be determined. The Swedish Obese Subjects (SOS) study is a prospective, controlled intervention study that examines the effects of bariatric surgery on hard end points. The aim of the present study was to examine the effect of bariatric surgery on cardiovascular events in the SOS study participants with type 2 diabetes.
All SOS study participants with type 2 diabetes at baseline were included in the analyses (n = 345 in the surgery group and n = 262 in the control group). Mean follow-up was 13.3 years (interquartile range 10.2–16.4) for all cardiovascular events.
Bariatric surgery was associated with a reduced myocardial infarction incidence (38 events among the 345 subjects in the surgery group vs. 43 events among the 262 subjects in the control group; log-rank P = 0.017; adjusted hazard ratio [HR] 0.56 [95% CI 0.34–0.93]; P = 0.025). No effect of bariatric surgery was observed on stroke incidence (34 events among the 345 subjects in the surgery group vs. 24 events among the 262 subjects in the control group; log-rank P = 0.852; adjusted HR 0.73 [0.41–1.30]; P = 0.29). The effect of surgery in reducing myocardial infarction incidence was stronger in individuals with higher serum total cholesterol and triglycerides at baseline (interaction P value = 0.02 for both traits). BMI (interaction P value = 0.12) was not related to the surgery outcome.
Bariatric surgery reduces the incidence of myocardial infarction in obese individuals with type 2 diabetes. Preoperative BMI should be integrated with metabolic parameters to maximize the benefits of bariatric surgery.
PMCID: PMC3507566  PMID: 22855732
5.  Monitoring of Lipids, Enzymes, and Creatine Kinase in Patients on Lipid-Lowering Drug Therapy 
Current Cardiology Reports  2013;15(9):397.
A number of plasma lipid parameters have been used to estimate cardiovascular risk and to be targets for treatment to reduce risk. Most risk algorithms are based on total cholesterol (T-C) or low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), and most intervention trials have targeted the LDL-C levels. Emerging measures, which in some cases may be better for risk calculation and as alternative treatment targets, are apolipoprotein B and non-HDL-C. Other lipid measures that may contribute in risk analysis are triglycerides (TG), lipoprotein(a), and lipoprotein-associated phospholipase A2. The primary treatment target in cardiovascular prevention is LDL-C, and potential alternative targets are apoB and non-HDL-C. In selected individuals at high cardiovascular (CV) risk, TG should be targeted, but HDL-C, Lp(a), and ratios such as LDL-C/HDL-C or apoB/apoAI are not recommended as treatment targets. Lipids should be monitored during titration to targets. Thereafter, lipids should be checked at least once a year or more frequently to improve treatment adherence if indicated. Monitoring of muscle and liver enzymes should be done before the start of treatment. In stable conditions during treatment, the focus should be on clinical symptoms that may alert muscle or liver complications. Routine measurement of CK or ALT is not necessary during treatment with statins.
PMCID: PMC3751280  PMID: 23888382
Dyslipidemia; Cardiovascular prevention; Statin; Lipoprotein; Myalgia; Treatment; Lipids; Enzymes; Creatine kinase; Lipid-lowering drug therapy
6.  PNPLA 3 I148M genetic variant associates with insulin resistance and baseline viral load in HCV genotype 2 but not in genotype 3 infection 
BMC Medical Genetics  2012;13:82.
Hepatic steatosis in HCV patients has been postulated as a risk factor associated with a higher frequency of fibrosis and cirrhosis. A single genetic variant, PNPLA3 I148M, has been widely associated with increased hepatic steatosis. Previous studies of the PNPLA3 I148M sequence variant in HCV infected individuals have reported an association between this variant and prevalence of steatosis, fibrosis, and cirrhosis. To evaluate the impact of PNPLA3 I148M variant on metabolic traits and treatment response in HCV genotype 2 and 3 infected patients.
Three hundred and eighty-two treatment naïve HCV genotype 2 or 3 infected patients were included in a phase III, open label, randomized, multicenter, investigator-initiated trial (the NORDynamIC study), in which pretreatment liver biopsies were mandatory. PNPLA3I148M genotyping was performed in a total of 359 Caucasian patients.
In HCV genotype 2 infected patients carrying the PNPLA3 148M allele, there was significantly increased insulin resistance (P = 0.023) and lower viral load (P = 0.005) at baseline as well as the first seven days of antiviral treatment. These results were not observed in HCV genotype 3 infected patients.
Our results suggest a possible association between the PNPLA3 148M allele and insulin resistance as well as baseline viral load in HCV genotype 2, but not in genotype 3.
PMCID: PMC3495049  PMID: 22978414
Hepatitis C; PNPLA 3; Insulin resistance; Viral load
7.  Paradoxical Lower Serum Triglyceride Levels and Higher Type 2 Diabetes Mellitus Susceptibility in Obese Individuals with the PNPLA3 148M Variant 
PLoS ONE  2012;7(6):e39362.
Obesity is highly associated with elevated serum triglycerides, hepatic steatosis and type 2 diabetes (T2D). The I148M (rs738409) genetic variant of patatin-like phospholipase domain-containing 3 gene (PNPLA3) is known to modulate hepatic triglyceride accumulation, leading to steatosis. No association between PNPLA3 I148M genotype and T2D in Europeans has been reported. Aim of this study is to examine the relationship between PNPLA3 I148M genotypes and serum triglycerides, insulin resistance and T2D susceptibility by testing a gene-environment interaction model with severe obesity.
Methods and Findings
PNPLA3 I148M was genotyped in a large obese cohort, the SOS study (n = 3,473) and in the Go-DARTS (n = 15,448), a T2D case-control study. Metabolic parameters were examined across the PNPLA3 I148M genotypes in participants of the SOS study at baseline and at 2- and 10-year follow up after bariatric surgery or conventional therapy. The associations with metabolic parameters were validated in the Go-DARTS study. Serum triglycerides were found to be lower in the PNPLA3 148M carriers from the SOS study at baseline and from the Go-DARTS T2D cohort. An increased risk for T2D conferred by the 148M allele was found in the SOS study (O.R. 1.09, 95% C.I. 1.01-1.39, P = 0.040) and in severely obese individuals in the Go-DARTS study (O.R. 1.37, 95% C.I. 1.13-1.66, P = 0.001). The 148M allele was no longer associated with insulin resistance or T2D after bariatric surgery in the SOS study and no association with the 148M allele was observed in the less obese (BMI<35) individuals in the Go-DARTS study (P for interaction  = 0.002). This provides evidence for the obesity interaction with I48M allele and T2D risk in a large-scale cross-sectional and a prospective interventional study.
Severely obese individuals carrying the PNPLA3 148M allele have lower serum triglyceride levels, are more insulin resistant and more susceptible to T2D. This study supports the hypothesis that obesity-driven hepatic lipid accumulation may contribute to T2D susceptibility.
PMCID: PMC3377675  PMID: 22724004
8.  The COBLL1 C allele is associated with lower serum insulin levels and lower insulin resistance in overweight and obese children 
Background Childhood obesity is a growing epidemic worldwide, and it is associated with metabolic complications, such as insulin resistance. Recently, a genetic variation (rs7607980) in the COBLL1 gene has been associated with lower insulin resistance in adults. The aim of the study was to investigate if the association between COBLL1 rs7607980 genetic variant and lower insulin resistance was present early in life.
Methods This sequence variant was genotyped in 878 overweight and obese children (mean age: 10 years) from Sardinia, Italy, from the outpatient clinic of the Pediatric Endocrine Unit, at the Regional Hospital for Microcitaemia in Cagliari. Insulin resistance was assessed by measurement of fasting circulating insulin levels before and after an oral glucose tolerance test and by HOMA-IR.
Results The COBLL1 rs7607980 C allele was associated with lower fasting insulin and HOMA-IR levels (p = 0.002 and p = 0.035, respectively) in overweight and obese children. Importantly, lower insulin levels were also observed 2 h after oral glucose tolerance test in C allele carriers (p = 0.009).
Conclusions The present study shows for the first time, the association between COBLL1 rs7607980 C allele, lower serum insulin levels and lower insulin resistance in overweight and obese children. Copyright © 2013 John Wiley & Sons, Ltd.
PMCID: PMC3799017  PMID: 23463496
COBLL1; insulin resistance; children; genetics; obesity; rs7607980

Results 1-8 (8)