The MHC Class II Antigen-Processing and Presentation Pathway Is Dysregulated in Type 1 Diabetes.

Peptide loading of MHC class II (MHCII) molecules is facilitated by HLA-DM (DM), which catalyzes CLIP release, stabilizes empty MHCII, and edits the MHCII-bound peptide repertoire. HLA-DO (DO) binds to DM and modulates its activity, resulting in an altered set of peptides presented at the cell surface. MHCII-peptide presentation in individuals with type 1 diabetes (T1D) is abnormal, leading to a breakdown in tolerance; however, no direct measurement of the MHCII pathway activity in T1D patients has been performed. In this study, we measured MHCII Ag-processing pathway activity in humans by determining MHCII, MHCII-CLIP, DM, and DO levels by flow cytometry for peripheral blood B cells, dendritic cells, and monocytes from 99 T1D patients and 97 controls. Results showed that MHCII levels were similar for all three APC subsets. In contrast, MHCII-CLIP levels, independent of sex, age at blood draw, disease duration, and diagnosis age, were significantly increased for all three APCs, with B cells showing the largest increase (3.4-fold). DM and DO levels, which usually directly correlate with MHCII-CLIP levels, were unexpectedly identical in T1D patients and controls. Gene expression profiling on PBMC RNA showed that DMB mRNA was significantly elevated in T1D patients with residual C-peptide. This resulted in higher levels of DM protein in B cells and dendritic cells. DO levels were also increased, suggesting that the MHCII pathway maybe differentially regulated in individuals with residual C-peptide. Collectively, these studies show a dysregulation of the MHCII Ag-processing pathway in patients with T1D.

Population Pharmacokinetics and Exposure-Response Modeling Analyses of Golimumab in Children and Young Adults With Recently Diagnosed Type 1 Diabetes.

Golimumab was recently evaluated in a phase 2a, randomized, double-blind, placebo-controlled, multicenter study (T1GER study) for safety and efficacy in children and young adults with newly diagnosed type 1 diabetes (T1D). Golimumab showed significant treatment effect where endogenous insulin production was preserved and clinical and metabolic parameters were improved. The objective of this report was to evaluate pharmacokinetic (PK) and pharmacodynamic data from the T1GER study by developing a population pharmacokinetic (PopPK) model and performing exposure-response (ER) analyses. The PopPK model was developed using data from the T1D study and 2 other pediatric studies with golimumab in ulcerative colitis and in polyarticular juvenile idiopathic arthritis. A 1-compartment model with first-order absorption and elimination was applied to describe the concentration-time profiles. Typical parameters normalized to the values in subjects with a standard weight of 70 kg were apparent clearance, 0.850 L/day; apparent volume of distribution, 16.0 L; and absorption rate constant, 1.01/day. From the ER analyses, no clear trends were observed for changes in both C-peptide area under the concentration-time curve and hemoglobin A1c levels for the relatively narrow exposure ranges following the body surface area-based dosing regimen used in this study. In conclusion, the developed PopPK model was able to adequately describe the observed PK of golimumab in patients with T1D. Although golimumab showed significant treatment effect, the ER analyses did not show clear trends within the active treatment group, which may indicate that the exposure from this T1D-specific dosing regimen was at the plateau of the ER curve.

Two-Year Follow-up From the T1GER Study: Continued Off-Therapy Metabolic Improvements in Children and Young Adults With New-Onset T1D Treated With Golimumab and Characterization of Responders.

OBJECTIVE: The T1GER (A Study of SIMPONI to Arrest ß-Cell Loss in Type 1 Diabetes) study showed many metabolic benefits of the tumor necrosis factor-α blocker golimumab in children and young adults with type 1 diabetes (T1D). Off-therapy effects are reported. RESEARCH DESIGNS AND METHODS: T1GER was a phase 2, placebo-controlled, randomized trial in which golimumab or placebo was administered for 52 weeks to participants 6-21 years old diagnosed with T1D within 100 days of randomization. Assessments occurred during the 52-week on-therapy and 52-week off-therapy periods. RESULTS: After treatment was stopped, C-peptide area under the curve (AUC) remained greater in the treatment versus control group. At weeks 78 and 104, the golimumab group had lower reductions in the 4-h C-peptide AUC baseline than the placebo group, where specifically the golimumab group had reductions of 0.31 and 0.41 nmol/L, and the placebo group had reductions of 0.64 and 0.74 nmol/L. There were also trends in less insulin use, higher peak C-peptide levels and those in partial remission, and higher peak C-peptide levels in the golimumab group. Golimumab responders, defined as having an increase or minimal loss of C-peptide AUC and/or being in partial remission at week 52, showed even greater improvements in most metabolic parameters on and off therapy and had less hypoglycemia during the off-therapy period versus placebo. Adverse events, including infections, were similar between the groups during all time periods of the study. CONCLUSIONS: In children and young adults with new-onset T1D, golimumab preserved endogenous ß-cell function and resulted in other favorable metabolic parameters on and off therapy. A subpopulation had disease stabilization while on therapy, with improved metabolic parameters off therapy.

Golimumab and Beta-Cell Function in Youth with New-Onset Type 1 Diabetes.

BACKGROUND: Type 1 diabetes is an autoimmune disease characterized by progressive loss of pancreatic beta cells. Golimumab is a human monoclonal antibody specific for tumor necrosis factor α that has already been approved for the treatment of several autoimmune conditions in adults and children. Whether golimumab could preserve beta-cell function in youth with newly diagnosed overt (stage 3) type 1 diabetes is unknown. METHODS: In this phase 2, multicenter, placebo-controlled, double-blind, parallel-group trial, we randomly assigned, in a 2:1 ratio, children and young adults (age range, 6 to 21 years) with newly diagnosed overt type 1 diabetes to receive subcutaneous golimumab or placebo for 52 weeks. The primary end point was endogenous insulin production, as assessed according to the area under the concentration-time curve for C-peptide level in response to a 4-hour mixed-meal tolerance test (4-hour C-peptide AUC) at week 52. Secondary and additional end points included insulin use, the glycated hemoglobin level, the number of hypoglycemic events, the ratio of fasting proinsulin to C-peptide over time, and response profile. RESULTS: A total of 84 participants underwent randomization - 56 were assigned to the golimumab group and 28 to the placebo group. The mean (±SD) 4-hour C-peptide AUC at week 52 differed significantly between the golimumab group and the placebo group (0.64±0.42 pmol per milliliter vs. 0.43±0.39 pmol per milliliter, P<0.001). A treat-to-target approach led to good glycemic control in both groups, and there was no significant difference between the groups in glycated hemoglobin level. Insulin use was lower with golimumab than with placebo. A partial-remission response (defined as an insulin dose-adjusted glycated hemoglobin level score [calculated as the glycated hemoglobin level plus 4 times the insulin dose] of ≤9) was observed in 43% of participants in the golimumab group and in 7% of those in the placebo group (difference, 36 percentage points; 95% CI, 22 to 55). The mean number of hypoglycemic events did not differ between the trial groups. Hypoglycemic events that were recorded as adverse events at the discretion of investigators were reported in 13 participants (23%) in the golimumab group and in 2 (7%) of those in the placebo group. Antibodies to golimumab were detected in 30 participants who received the drug; 29 had antibody titers lower than 1:1000, of whom 12 had positive results for neutralizing antibodies. CONCLUSIONS: Among children and young adults with newly diagnosed overt type 1 diabetes, golimumab resulted in better endogenous insulin production and less exogenous insulin use than placebo. (Funded by Janssen Research and Development; T1GER ClinicalTrials.gov number, NCT02846545.).

Parent Preferences for Delaying Insulin Dependence in Children at Risk of Stage III Type 1 Diabetes.

Background: Autoantibody screening in type 1 diabetes (T1D) may reduce the chances of potentially life-threatening diabetic ketoacidosis (DKA) at diagnosis by allowing individuals at risk of progression to more actively monitor for and/or manage progression to insulin dependence. We investigated parents' preferences for treatments to delay the onset of insulin dependence in children who are at high risk of developing Stage III T1D. Methods: A web-based survey (n = 1501) was administered to a stratified sample of parents (children <18 years) in the United States from an online panel. Parents were told to hypothetically assume that their youngest child would become insulin dependent within 6 months or 2 years and were offered a series of choices between no treatment and two hypothetical treatments that would delay insulin dependence. Random-parameters logit analysis and maximum acceptable risks were used to evaluate the relative importance of treatment benefits and risks. Results: Most parents chose at least one active treatment (2% always chose monitoring only). For parents of children without T1D (n = 901), delaying insulin dependence and reducing the risk of long-term health complications and serious infection were the most important treatment attributes. In addition, parents of children with T1D (n = 600) also valued reducing the risk of hospitalizations due to DKA. Conclusions: When told to assume their child would develop Stage III T1D, most parents considered active treatments to delay progression. For medicines under development to delay insulin dependence in T1D, the preferences expressed in this survey provide guidance on acceptable benefit-risk trade-offs.

Type 1 Diabetes: Disease Stratification.

Type 1 diabetes, a disorder characterized by immune-mediated loss of functional pancreatic beta cells, is a disease continuum with specific presymptomatic stages with defined risk of progression to symptomatic disease. Prognostic biomarkers have been developed for disease staging and for stratification of subjects that address the heterogeneity in rate of disease progression. Using biomarkers for stratification of subjects at different stages of type 1 diabetes will enable smaller and shorter intervention clinical trials with greater effect size. Addressing the heterogeneity of the disease will allow precision medicine-based approaches to prevention and interception of presymptomatic stages of disease and treatment and cure of symptomatic disease.

Small-molecule inhibitors of FABP4/5 ameliorate dyslipidemia but not insulin resistance in mice with diet-induced obesity.

Fatty acid binding protein-4 (FABP4) and FABP5 are two closely related FA binding proteins expressed primarily in adipose tissue and/or macrophages. The small-molecule FABP4 inhibitor BMS309403 was previously reported to improve insulin sensitivity in leptin-deficient Lep(ob)/Lep(ob) (ob/ob) mice. However, this compound was not extensively characterized in the more physiologically relevant animal model of mice with diet-induced obesity (DIO). Here, we report the discovery and characterization of a novel series of FABP4/5 dual inhibitors represented by Compounds 1-3. Compared with BMS309403, the compounds had significant in vitro potency toward both FABP4 and FABP5. In cell-based assays, Compounds 2 and 3 were more potent than BMS309403 to inhibit lipolysis in 3T3-L1 adipocytes and in primary human adipocytes. They also inhibited MCP-1 release from THP-1 macrophages as well as from primary human macrophages. When chronically administered to DIO mice, BMS309403 and Compound 3 reduced plasma triglyceride and free FA levels. Compound 3 reduced plasma free FAs at a lower dose level than BMS309403. However, no significant change was observed in insulin, glucose, or glucose tolerance. Our results indicate that the FABP4/5 inhibitors ameliorate dyslipidemia but not insulin resistance in DIO mice.

Gender-dependent effect of Gpbar1 genetic deletion on the metabolic profiles of diet-induced obese mice.

G-protein-coupled bile acid receptor 1 (GPBAR1/TGR5/M-Bar/GPR131) is a cell surface receptor involved in the regulation of bile acid metabolism. We have previously shown that Gpbar1-null mice are resistant to cholesterol gallstone disease when fed a lithogenic diet. Other published studies have suggested that Gpbar1 is involved in both energy homeostasis and glucose homeostasis. Here, we examine the functional role of Gpbar1 in diet-induced obese mice. We found that body weight, food intake, and fasted blood glucose levels were similar between Gpbar1-null mice and their wild-type (WT) littermates when fed a chow or high-fat diet (HFD) for 2 months. However, insulin tolerance tests revealed improved insulin sensitivity in male Gpbar1(-/-) mice fed chow, but impaired insulin sensitivity when fed a HFD. In contrast, female Gpbar1(-/-) mice exhibited improved insulin sensitivity when fed a HFD compared with their WT littermates. Female Gpbar1(-/-) mice had significantly lower plasma cholesterol and triglyceride levels than their WT littermates on both diets. Male Gpbar1(-/-) mice on HFD displayed increased hepatic steatosis when compared with Gpbar1(+)(/)(+) males and Gpbar1(-/-) females on HFD. These results suggest a gender-dependent regulation of Gpbar1 function in metabolic disease.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) affects gene expression pathways beyond cholesterol metabolism in liver cells.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) induces degradation of low-density lipoprotein receptor (LDLR) in the liver. It is being pursued as a therapeutic target for LDL-cholesterol reduction. Earlier genome-wide gene expression studies showed that PCSK9 over-expression in HepG2 cells resulted in up-regulation of genes in cholesterol biosynthesis and down-regulation of genes in stress response pathways; however, it was not known whether these changes were directly regulated by PCSK9 or were secondary to PCSK9-induced changes to the intracellular environment. In order to further understand the biological function of PCSK9 we treated HepG2 cells with purified recombinant wild type (WT) and D374Y gain-of-function PCSK9 proteins for 8, 24, and 48 h, and used microarray analysis to identify genome-wide expression changes and pathways. These results were compared to the changes induced by culturing HepG2 cells in cholesterol-free medium, mimicking the intracellular environment of cholesterol starvation. We determined that PCSK9-induced up-regulation of cholesterol biosynthesis genes resulted from intracellular cholesterol starvation. In addition, we identified novel pathways that are presumably regulated by PCSK9 and are independent of its effects on cholesterol uptake. These pathways included "protein ubiquitination," "xenobiotic metabolism," "cell cycle," and "inflammation and stress response." Our results indicate that PCSK9 affects metabolic pathways beyond cholesterol metabolism in HepG2 cells.

Targeting PCSK9 for the treatment of hypercholesterolemia.

PCSK9 (proprotein convertase subtilisin/kexin type 9) mediates the post-translational degradation of the LDL receptor (LDLR) and, as a result, modulates serum levels of LDL-cholesterol (LDL-C). Individuals with gain-of-function mutations in the PCSK9 gene exhibit high serum levels of LDL-C, while those with loss-of-function mutations have low serum levels of LDL-C and are protected from heart disease. Similarly, mice lacking the expression of PCSK9 exhibit higher levels of LDLR in the liver and reduced serum cholesterol, while the overexpression of PCSK9 reduces LDLR and results in increased serum cholesterol. Thus, as a novel, validated target for controlling serum levels of LDL-C, PCSK9 has attracted research attention. The biological inhibition of PCSK9 appears feasible, and preclinical programs based on RNAi targeting of the protein are at an advanced stage. In contrast, the development of conventional small-molecule therapeutics to inhibit PCSK9 continues to present challenges.

GPR119 is required for physiological regulation of glucagon-like peptide-1 secretion but not for metabolic homeostasis.

G protein-coupled receptor 119 (GPR119) is expressed in pancreatic islets and intestine, and is involved in insulin and incretin hormone release. GPR119-knockout (Gpr119(-/-)) mice were reported to have normal islet morphology and normal size, body weight (BW), and fed/fasted glucose levels. However, the physiological function of GPR119 and its role in maintaining glucose homeostasis under metabolic stress remain unknown. Here, we report the phenotypes of an independently generated line of Gpr119(-/-) mice under basal and high-fat diet (HFD)-induced obesity. Under low-fat diet feeding, Gpr119(-/-) mice show normal plasma glucose and lipids, but have lower BWs and lower post-prandial levels of active glucagon-like peptide 1 (GLP-1). Nutrient-stimulated GLP-1 release is attenuated in Gpr119(-/-) mice, suggesting that GPR119 plays a role in physiological regulation of GLP-1 secretion. Under HFD-feeding, both Gpr119(+)(/)(+) and Gpr119(-/-) mice gain weight similarly, develop hyperinsulinemia and hyperleptinemia, but not hyperglycemia or dyslipidemia. Glucose and insulin tolerance tests did not reveal a genotypic difference. These data show that GPR119 is not essential for the maintenance of glucose homeostasis. Moreover, we found that oleoylethanolamide (OEA), reported as a ligand for GPR119, was able to suppress food intake in both Gpr119(+)(/)(+) and Gpr119(-/-) mice, indicating that GPR119 is not required for the hypophagic effect of OEA. Our results demonstrate that GPR119 is important for incretin and insulin secretion, but not for appetite suppression.

Nmur1-/- mice are not protected from cutaneous inflammation.

Neuromedin U (Nmu) is a neuropeptide expressed primarily in the gastrointestinal tract and central nervous system. Previous reports have identified two G protein-coupled receptors (designated Nmur1 and Nmur2) that bind Nmu. Recent reports suggest that Nmu mediates immune responses involving mast cells, and Nmur1 has been proposed to mediate these responses. In this study, we generated mice with an Nmur1 deletion and then profiled the responses of these mice in a cutaneous inflammation model utilizing complete Freund's adjuvant (CFA). We report here that mice lacking Nmur1 had normal inflammation responses with moderate changes in serum cytokines compared to Nmur1(+/+) littermates. Although differences in IL-6 were observed in mice lacking Nmu peptide, these mice exhibited a normal response to CFA. Our data argues against a major role for Nmur1 in mediating the reported inflammatory functions of NmU.

Lack of FFAR1/GPR40 does not protect mice from high-fat diet-induced metabolic disease.

OBJECTIVE: FFAR1/GPR40 is a G-protein-coupled receptor expressed predominantly in pancreatic islets mediating free fatty acid-induced insulin secretion. However, the physiological role of FFAR1 remains controversial. It was previously reported that FFAR1 knockout (Ffar1(-/-)) mice were resistant to high-fat diet-induced hyperinuslinemia, hyperglycemia, hypertriglyceridemia, and hepatic steatosis. A more recent report suggested that although FFAR1 was necessary for fatty acid-induced insulin secretion in vivo, deletion of FFAR1 did not protect pancreatic islets against fatty acid-induced islet dysfunction. This study is designed to investigate FFAR1 function in vivo using a third line of independently generated Ffar1(-/-) mice in the C57BL/6 background. RESEARCH DESIGN AND METHODS: We used CL-316,243, a beta3 adrenergic receptor agonist, to acutely elevate blood free fatty acids and to study its effect on insulin secretion in vivo. Ffar1(+/+) (wild-type) and Ffar1(-/-) (knockout) mice were placed on two distinct high-fat diets to study their response to diet-induced obesity. RESULTS: Insulin secretion was reduced by approximately 50% in Ffar1(-/-) mice, confirming that FFAR1 contributes significantly to fatty acid stimulation of insulin secretion in vivo. However, Ffar1(+/+) and Ffar1(-/-) mice had similar weight, adiposity, and hyperinsulinemia on high-fat diets, and Ffar1(-/-) mice showed no improvement in glucose or insulin tolerance tests. In addition, high-fat diet induced comparable levels of lipid accumulation in livers of Ffar1(+/+) and Ffar1(-/-) mice. CONCLUSIONS: FFAR1 is required for normal insulin secretion in response to fatty acids; however, Ffar1(-/-) mice are not protected from high-fat diet-induced insulin resistance or hepatic steatosis.

PCSK9 binds to multiple receptors and can be functionally inhibited by an EGF-A peptide.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low density lipoprotein receptor (LDLR) and induces its internalization and degradation. PCSK9 binding to LDLR is mediated through the LDLR epidermal growth factor-like repeat A (EGF-A) domain. We show for the first time that an EGF-A peptide inhibits PCSK9-mediated degradation of LDLR in HepG2 cells. In addition to LDLR, we show that PCSK9 also binds directly to ApoER2 and mouse VLDLR. Importantly, binding of PCSK9 to either LDLR or mouse VLDLR was effectively inhibited by EGF-A while binding to ApoER2 was less affected. In contrast, LDL receptor-associated protein (RAP), which interacts with LDL receptor repeat type A (LA) domains, inhibited PCSK9 binding to ApoER2 with greater efficacy than either LDLR or mVLDLR. These data demonstrate that while PCSK9 binds several receptors via its EGF-A binding domain, additional contacts with other receptor domains are also involved.

P518/Qrfp sequence polymorphisms in SAMP6 osteopenic mouse.

Mice lacking GPR103A expression display osteopenia. Analysis of mouse quantitative trait loci literature associated with bone mineral density suggested GPR103A ligand P518/Qrfp (chromosome 2qB) as a candidate osteoporosis gene. Promoter and coding regions of mouse P518/Qrfp were sequenced from genomic DNA obtained from the osteoporosis-prone strain SAMP6 and control strains SAMR1, A/J, AKR/J, BALB/c, C3H/HeJ, C57BL/6J, and DBA/2J. Four single-nucleotide polymorphisms (SNPs) were identified in only SAMP6 genomic DNA, g.-1773 T-->C, g.110 A-->G (N37S), g.188 G-->A (R63K), and g.135 T-->C (H45H). The promoter SNP generated a novel neuron-restrictive silencing factor binding site, a repressor that decreases gene expression in nonneuronal tissues. TaqMan analysis demonstrated fivefold lower P518/Qrfp liver expression in SAMP6 versus SAMR1 or C57BL/6J control strains. Tissue distribution of human, mouse, and rat P518/Qrfp and its receptors showed expression in bone and spinal cord. A direct role for P518/Qrfp function in maintaining bone mineral density is suggested.

Murine CXCR1 is a functional receptor for GCP-2/CXCL6 and interleukin-8/CXCL8.

Functional interleuin-8 (IL-8) receptors (IL-8RA and IL-8RB: CXCR1 and CXCR2, respectively) have been described in human, monkey, dog, rabbit, and guinea pig. Although three IL-8R homologues have been found in rat, only one of these, rat CXCR2, appears to be functional based on responsiveness to ligands. Similarly, CXC chemokines induce biological responses through the murine homolog of CXCR2, but the identification of functional rodent CXCR1 homologues has remained elusive. We have identified and characterized the mouse CXCR1 homologue (mCXCR1). Murine CXCR1 shares 68 and 88% amino acid identity with its human and rat counterparts, respectively. Similar to the tissue distribution pattern of rat CXCR1, we found murine CXCR1 mRNA expression predominantly in lung, stomach, bone marrow, and leukocyte-rich tissues. In contrast to previous reports, we determined that mCXCR1 is a functional receptor. We show predominant engagement of this receptor by mouse GCP-2/CXCL6, human GCP-2, and IL-8/CXCL8 by binding, stimulation of GTPgammaS exchange, and chemotaxis of mCXCR1-transfected cells. Furthermore, murine CXCR1 is not responsive to the human CXCR2 ligands ENA-78/CXCL5, NAP-2/CXCL7, GRO-alpha, -beta, -gamma/CXCL1-3, or rat CINC-1-3. In addition, we show concomitant elevation of mCXCR1 and its proposed major ligand, GCP-2, positively correlated with paw swelling in murine collagen-induced arthritis. This report represents the first description of a functional CXCR1-like receptor in rodents.

An acute care surgery model improves outcomes in patients with appendicitis.

OBJECTIVE: To compare outcomes of appendectomy in an Acute Care Surgery (ACS) model to that of a traditional home-call attending surgeon model. SUMMARY BACKGROUND DATA: Acute care surgery (ACS, a combination of trauma surgery, emergency surgery, and surgical critical care) has been proposed as a practice model for the future of general surgery. To date, there are few data regarding outcomes of surgical emergencies in the ACS model. METHODS: Between September 1999 and August 2002, surgical emergencies were staffed at the faculty level by either an in-house trauma/emergency surgeon (ACS model) or a non-trauma general surgeon taking home call (traditional [TRAD] model). Coverage alternated monthly. Other aspects of hospital care, including resident complement, remained unchanged. We retrospectively reviewed key time intervals (emergency department [ED] presentation to surgical consultation; surgical consultation to operation [OR]; and ED presentation to OR) and outcomes (rupture rate, negative appendectomy rate, complication rate, and hospital length of stay [LOS]) for patients treated in the ACS and TRAD models. Questions of interest were examined using chi tests for discrete variables and independent sample t test for comparison of means. RESULTS: During the study period, 294 appendectomies were performed. In-house ACS surgeons performed 167 procedures, and the home-call TRAD surgeons performed 127 procedures. No difference was found in the time from ED presentation to surgical consultation; however, the time interval from consultation to OR was significantly decreased in the ACS model (TRAD 7.6 hours vs. ACS 3.5 hours, P < 0.05). As a result, the total time from ED presentation to OR was significantly shorter in the ACS model (TRAD 14.0 hours vs. ACS 10.1 hour, P < 0.05). Rupture rates were decreased in the ACS model (TRAD 23.3% vs. ACS 12.3%, P < 0.05); negative appendectomy rates were similar. The complication rate in the ACS model was decreased (TRAD 17.4% vs. ACS 7.7%, P < 0.05), as was the hospital LOS (TRAD 3.5 days vs. ACS 2.3 days, P < 0.001). CONCLUSIONS: In patients with acute appendicitis, the presence of an in-house acute care surgeon significantly decreased the time to operation, rupture rate, complication rate, and hospital length of stay. The ACS model appears to improve outcomes of acute appendicitis compared with a TRAD home-call model. This study supports the efficacy and efficiency of the ACS model in the management of surgical emergencies.

Targeted deletion of Gpbar1 protects mice from cholesterol gallstone formation.

The Gpbar1 [G-protein-coupled BA (bile acid) receptor 1] is a recently identified cell-surface receptor that can bind and is activated by BAs, but its physiological role is unclear. Using targeted deletion of the Gpbar1 gene in mice, we show that the gene plays a critical role in the maintenance of bile lipid homoeostasis. Mice lacking Gpbar1 expression were viable, developed normally and did not show significant difference in the levels of cholesterol, BAs or any other bile constituents. However, they did not form cholesterol gallstones when fed a cholic acid-containing high-fat diet, and liver-specific gene expression indicated that Gpbar1-deficient mice have altered feedback regulation of BA synthesis. These results suggest that Gpbar1 plays a critical role in the formation of gallstones, possibly via a regulatory mechanism involving the cholesterol 7alpha-hydroxylase pathway.

The evolving role of interventional radiology in trauma care.

BACKGROUND: Although the traditional role of radiology in trauma care has been diagnostic, therapeutic interventional radiology (IR) techniques have now become essential in the management of many injuries. We hypothesized that IR has evolved at our institution over the last decade from a largely diagnostic to a more therapeutic role in the care of the injured patient. METHODS: Demographic information, computed tomographic scans of the chest and abdomen, and angiographic procedures (APs) performed within 48 hours of admission were reviewed in all patients evaluated at a Level I trauma center for the periods 1993 to 1995 and 2000 to 2002. All APs performed with the intent to embolize, stent, or insert a device into a vessel were designated as therapeutic. Analysis by means of chi provided between-group comparisons for questions of interest and the Student's t test was used for comparison of means. RESULTS: A total of 4,750 patients were reviewed, 1,677 from the time period 1993 to 1995 and 3,073 from the period 2000 to 2002. Overall injury severity as measured by the Injury Severity Score (ISS) was similar in both groups (9.6 vs. 9.9, p = not significant). The number of angiograms obtained decreased significantly from 7.1% to 4.0% of all patients (p < 0.01). Concurrently, the fraction of all angiograms that were considered therapeutic rose from 10% to 22% (p < 0.05). The overall number of aortic arch angiograms decreased over time (from 3.6% to 0.9%, p < 0.01), and the percentage of positive examinations increased from 5.0% to 21.4%. In comparison, the number of computed tomographic scans of the chest increased from 1.6% of all patients to 10.8% (p < 0.01). CONCLUSION: Axial imaging studies are being used more frequently to screen trauma patients for injury. Concurrently, diagnostic APs are less frequently performed but are more frequently positive. In addition, IR studies are increasingly focused on therapeutic intervention. IR program development and support is an integral aspect of modern trauma care. These findings have prompted our institution to equip the IR suite to function as an active resuscitation area similar to the trauma bay and intensive care unit.