Effective treatment of steatosis and steatohepatitis by fibroblast growth factor 1 in mouse models of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder and is strongly associated with obesity and type 2 diabetes. Currently, there is no approved pharmacological treatment for this disease, but improvement of insulin resistance using peroxisome proliferator-activated receptor-γ (PPARγ) agonists, such as thiazolidinediones (TZDs), has been shown to reduce steatosis and steatohepatitis effectively and to improve liver function in patients with obesity-related NAFLD. However, this approach is limited by adverse effects of TZDs. Recently, we have identified fibroblast growth factor 1 (FGF1) as a target of nuclear receptor PPARγ in visceral adipose tissue and as a critical factor in adipose remodeling. Because FGF1 is situated downstream of PPARγ, it is likely that therapeutic targeting of the FGF1 pathway will eliminate some of the serious adverse effects associated with TZDs. Here we show that pharmacological administration of recombinant FGF1 (rFGF1) effectively improves hepatic inflammation and damage in leptin-deficient ob/ob mice and in choline-deficient mice, two etiologically different models of NAFLD. Hepatic steatosis was effectively reduced only in ob/ob mice, suggesting that rFGF1 stimulates hepatic lipid catabolism. Potentially adverse effects such as fibrosis or proliferation were not observed in these models. Because the anti-inflammatory effects were observed in both the presence and absence of the antisteatotic effects, our findings further suggest that the anti-inflammatory property of rFGF1 is independent of its effect on lipid catabolism. Our current findings indicate that, in addition to its potent glucose-lowering and insulin-sensitizing effects, rFGF1 could be therapeutically effective in the treatment of NAFLD.Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in developed countries and is strongly associated with obesity and type 2 diabetes (1). NAFLD refers to a wide spectrum of liver disorders ranging from simple fatty liver (steatosis) to nonalcoholic steatohepatitis (NASH) with increased risk of developing progressive fibrosis, cirrhosis, and liver cancer (2).Treatment options for NAFLD are limited and are directed mainly at weight loss or pharmacological improvement of insulin resistance (3). Although no pharmacologic therapy has been approved, the thiazolidinedione (TZD) class of insulin sensitizers has been demonstrated to improve steatosis, steatohepatitis, and liver function in mice and patients with NAFLD (1). TZDs improve insulin sensitivity through activation of nuclear receptor peroxisome proliferator-activated receptor-gamma (PPARγ), which reduces insulin resistance in adipose tissue, liver, and skeletal muscle (4). The exact mechanism by which PPARγ exerts its beneficial effects on NAFLD is not completely understood, but it is believed that improved hepatic insulin sensitivity enhances lipid oxidation and reduces hepatic lipogenesis, thereby reducing steatosis (5). In addition, increased peripheral insulin sensitivity may reduce lipolysis in white adipose tissue and thereby limit ectopic fat accretion.PPARγ and its activators also have broad anti-inflammatory effects. On one hand, PPARγ has been shown to attenuate the expression and secretion of proinflammatory cytokines (including IL-1β and TNF-α) associated with M1 macrophages (6); on the other hand, it reduces macrophage activity via transrepression of NF-κB (7). Despite their efficacy in glycemic control and reduction of steatosis, TZDs are associated with various serious adverse side effects, including weight gain, fluid retention, osteoporosis, and cardiovascular toxicity, which have strongly limited their clinical use (4). These limitations highlight the need for novel approaches such as more selective PPARγ agonists or direct activation of downstream targets.Recently we have identified fibroblast growth factor 1 (FGF1) as a target of PPARγ in visceral adipose tissue and as a critical factor in adipose remodeling (8). Mice with an FGF1 deficiency displayed a severe diabetic phenotype with increased inflammation and fibrosis in adipose tissue. Conversely, pharmacological treatment with recombinant FGF1 (rFGF1) has a potent insulin-sensitizing effect at the systemic level, and in the liver it effectively reduces steatosis in ob/ob mice (9). It remains unclear, however, if and to what extent the hepatic effects of FGF1 are direct or indirect.In this study we used two etiologically different models of NAFLD to determine the mechanism by which rFGF1 improves liver disease: leptin-deficient ob/ob mice, which develop steatosis primarily through excessive food intake, and mice with a dietary choline deficiency, which develop steatosis primarily as a result of a defect in hepatic lipid catabolism (10). Interestingly, we found that rFGF1 effectively reverses steatosis in ob/ob mice but not in mice with a dietary choline deficiency, suggesting that rFGF1 stimulates hepatic lipid catabolism. rFGF1 treatment improved steatohepatitis and plasma alanine transaminase activity (ALT) in both models, indicating that the effects of rFGF1 on hepatic inflammation and liver function are independent of its antisteatotic properties. Together our results provide insight into the mechanism by which rFGF1 improves NAFLD and highlight its potential therapeutic value in the treatment of different aspects of liver disease.     

Implementation of Clinical Pharmacogenomics within a Large Health System: From Electronic Health Record Decision Support to Consultation Services

The number of clinically relevant gene‐based guidelines and recommendations pertaining to drug prescribing continues to grow. Incorporating gene–drug interaction information into the drug‐prescribing process can help optimize pharmacotherapy outcomes and improve patient safety. However, pharmacogenomic implementation barriers exist such as integration of pharmacogenomic results into electronic health records (EHRs), development and deployment of pharmacogenomic decision support tools to EHRs, and feasible models for establishing ambulatory pharmacogenomic clinics. We describe the development of pharmacist‐managed pharmacogenomic services within a large health system. The Clinical Pharmacogenetics Implementation Consortium guidelines for HLA‐B*57:01‐abacavir, HLA‐B*15:02‐carbamazepine, and TPMT‐thiopurines (i.e., azathioprine, mercaptopurine, and thioguanine) were systematically integrated into patient care. Sixty‐three custom rules and alerts (20 for TPMT‐thiopurines, 8 for HLA‐B*57:01‐abacavir, and 35 for HLA‐B*15:02‐anticonvulsants) were developed and deployed to the EHR for the purpose of providing point‐of‐care pharmacogenomic decision support. In addition, a pharmacist and physician‐geneticist collaboration established a pharmacogenomics ambulatory clinic. This clinic provides genetic testing when warranted, result interpretation along with pharmacotherapy recommendations, and patient education. Our processes for developing these pharmacogenomic services and solutions for addressing implementation barriers are presented.     

Tubular network formation protects mitochondria from autophagosomal degradation during nutrient starvation

Mitochondria are highly dynamic organelles that mediate essential cell functions such as apoptosis and cell-cycle control in addition to their role as efficient ATP generators. Mitochondrial morphology changes are tightly regulated, and their shape can shift between small, fragmented units and larger networks of elongated mitochondria. We demonstrate that mitochondrial elements become significantly elongated and interconnected shortly after nutrient depletion. This mitochondrial morphological shift depends on the type of starvation, with an additive effect observed when multiple nutrients are depleted simultaneously. We further show that starvation-induced mitochondrial elongation is mediated by down-regulation of dynamin-related protein 1 (Drp1) through modulation of two Drp1 phosphorylation sites, leading to unopposed mitochondrial fusion. Finally, we establish that mitochondrial tubulation upon nutrient deprivation protects mitochondria from autophagosomal degradation, which could permit mitochondria to maximize energy production and supply autophagosomal membranes during starvation.     

In vivo diagnosis of murine pancreatic intraepithelial neoplasia and early-stage pancreatic cancer by molecular imaging

Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with poor patient outcome often resulting from late diagnosis in advanced stages. To date methods to diagnose early-stage PDAC are limited and in vivo detection of pancreatic intraepithelial neoplasia (PanIN), a preinvasive precursor of PDAC, is impossible. Using a cathepsin-activatable near-infrared probe in combination with flexible confocal fluorescence lasermicroscopy (CFL) in a genetically defined mouse model of PDAC we were able to detect and grade murine PanIN lesions in real time in vivo. Our diagnostic approach is highly sensitive and specific and proved superior to clinically established fluorescein-enhanced imaging. Translation of this endoscopic technique into the clinic should tremendously improve detection of pancreatic neoplasia, thus reforming management of patients at risk for PDAC.     

EPIBLASTER-fast exhaustive two-locus epistasis detection strategy using graphical processing units

Detection of epistatic interaction between loci has been postulated to provide a more in-depth understanding of the complex biological and biochemical pathways underlying human diseases. Studying the interaction between two loci is the natural progression following traditional and well-established single locus analysis. However, the added costs and time duration required for the computation involved have thus far deterred researchers from pursuing a genome-wide analysis of epistasis. In this paper, we propose a method allowing such analysis to be conducted very rapidly. The method, dubbed EPIBLASTER, is applicable to case-control studies and consists of a two-step process in which the difference in Pearson's correlation coefficients is computed between controls and cases across all possible SNP pairs as an indication of significant interaction warranting further analysis. For the subset of interactions deemed potentially significant, a second-stage analysis is performed using the likelihood ratio test from the logistic regression to obtain the P-value for the estimated coefficients of the individual effects and the interaction term. The algorithm is implemented using the parallel computational capability of commercially available graphical processing units to greatly reduce the computation time involved. In the current setup and example data sets (211 cases, 222 controls, 299468 SNPs; and 601 cases, 825 controls, 291095 SNPs), this coefficient evaluation stage can be completed in roughly 1 day. Our method allows for exhaustive and rapid detection of significant SNP pair interactions without imposing significant marginal effects of the single loci involved in the pair.     

Effect of rituximab on physical function and quality of life in patients with rheumatoid arthritis previously untreated with methotrexate

Objective

To assess the effect of rituximab plus methotrexate (MTX) compared with MTX alone on patient‐reported outcomes (PROs) and health‐related quality of life (HRQOL) in patients with active early rheumatoid arthritis (RA) previously untreated with MTX.

Methods

Patients with active early RA were randomized to groups receiving placebo, rituximab 500 mg, or rituximab 1,000 mg. Rituximab was given by intravenous infusion on days 1 and 15. From week 24, patients with a Disease Activity Score in 28 joints–erythrocyte sedimentation rate of ≥2.6 were eligible for retreatment. Physical function was assessed by Health Assessment Questionnaire (HAQ) disability index (DI) and Short Form 36 (SF‐36) scores. Patients achieving a minimal clinically important difference (MCID) for PROs were determined. Additional PROs, including fatigue and pain, were assessed.

Results

A total of 748 patients were randomized and received the study drug. Patient characteristics were well balanced. At week 52, treatment with rituximab in both dose groups showed significant improvements in the HAQ DI compared to the MTX alone group (?0.905 and ?0.916 in the rituximab 500 mg plus MTX and 1,000 mg plus MTX groups, respectively, versus ?0.628 in the MTX alone group; P < 0.0001). Higher proportions of patients achieved MCID in the HAQ DI in the rituximab plus MTX groups compared to MTX alone. Treatment with rituximab plus MTX led to a significant reduction in the SF‐36 physical component summary for both rituximab dose groups, but did not show statistically significant differences in the SF‐36 mental component summary. Compared to the MTX alone group, both doses of rituximab plus MTX were associated with significant reductions in the patient global assessment of disease activity and pain, and a significantly higher improvement in Functional Assessment of Chronic Illness Therapy–Fatigue scores from baseline to 52 weeks.

Conclusions

Rituximab plus MTX was associated with significant improvement in physical function and HRQOL outcomes compared with MTX alone in patients previously untreated with MTX.

     

Serotonin transporter gene and childhood trauma--a G × E effect on anxiety sensitivity

Background: Genetic factors and environmental factors are assumed to interactively influence the pathogenesis of anxiety disorders. Thus, a gene–environment interaction (G × E) study was conducted with respect to anxiety sensitivity (AS) as a promising intermediate phenotype of anxiety disorders. Method: Healthy subjects ( N = 363) were assessed for AS, childhood maltreatment (Childhood Trauma Questionnaire), and genotyped for functional serotonin transporter gene variants (5‐HTTLPR/5‐HTT rs25531). The influence of genetic and environmental variables on AS and its subdimensions was determined by a step‐wise hierarchical regression and a multiple indicator multiple cause (MIMIC) model. Results: A significant G × E effect of the more active 5‐HTT genotypes and childhood maltreatment on AS was observed. Furthermore, genotype (LL)–childhood trauma interaction particularly influenced somatic AS subdimensions, whereas cognitive subdimensions were affected by childhood maltreatment only. Conclusions: Results indicate a G × E effect of the more active 5‐HTT genotypes and childhood maltreatment on AS, with particular impact on its somatic subcomponent. Depression and Anxiety, 2011. © 2011 Wiley Periodicals, Inc.