Variability of cyclosporine concentrations by HPLC and TDX monoclonal assay methods, application of a correction factor, and description of a novel clinical approach to determine the practical consequences of changing assay technique.

Cyclosporine (CSA) is an immunosuppressant used for the prevention of graft rejection and graft-versus-host disease (GVHD) during hematopoietic stem cell transplantation. Therapeutic drug monitoring (TDM) is recommended to ensure efficacy and prevent toxicity. Several immunoassay assay are commercially available for measuring CSA drug concentrations.

[Hyperlipidemia in hepatic MED1 deficient mice in response to fasting].

MED1 is a key transcription co-activator subunit of the Mediator complex that is essential for RNA polymerase II-dependent transcription. MED1 functions as a co-activator for PPARs and other nuclear receptors and transcription factors, and plays an important role in lipid metabolism. To examine how MED1 might affect plasma lipids, plasma triglyceride, cholesterol levels, and lipoprotein profiles, were measured in MED1(deltaLiv) mice fasted for 24, 48 and 72 hours.

Sustained activation of PPARα by endogenous ligands increases hepatic fatty acid oxidation and prevents obesity in ob/ob mice.

Obesity, a major health concern, results from an imbalance between energy intake and expenditure. Leptin-deficient ob/ob mice are paradigmatic of obesity, resulting from excess energy intake and storage. Mice lacking acyl-CoA oxidase 1 (Acox1), the first enzyme of the peroxisomal fatty acid β-oxidation system, are characterized by increased energy expenditure and a lean body phenotype caused by sustained activation of peroxisome proliferator-activated receptor α (PPARα) by endogenous ligands in liver that remain unmetabolized in the absence of Acox1.

Progressive endoplasmic reticulum stress contributes to hepatocarcinogenesis in fatty acyl-CoA oxidase 1-deficient mice.

Fatty acyl-coenzyme A oxidase 1 (ACOX1) knockout (ACOX1(-/-)) mice manifest hepatic metabolic derangements that lead to the development of steatohepatitis, hepatocellular regeneration, spontaneous peroxisome proliferation, and hepatocellular carcinomas. Deficiency of ACOX1 results in unmetabolized substrates of this enzyme that function as biological ligands for peroxisome proliferator-activated receptor-α (PPARα) in liver. Here we demonstrate that sustained activation of PPARα in ACOX1(-/-) mouse liver by these ACOX1 substrates results in endoplasmic reticulum (ER) stress.

Transcription coactivator mediator subunit MED1 is required for the development of fatty liver in the mouse.

Unlabelled: Peroxisome proliferator-activated receptor-γ (PPARγ), a nuclear receptor, when overexpressed in liver stimulates the induction of adipocyte-specific and lipogenesis-related genes and causes hepatic steatosis. We report here that Mediator 1 (MED1; also known as PBP or TRAP220), a key subunit of the Mediator complex, is required for high-fat diet-induced hepatic steatosis as well as PPARγ-stimulated adipogenic hepatic steatosis. Mediator forms the bridge between transcriptional activators and RNA polymerase II.

Coactivators in PPAR-Regulated Gene Expression.

Peroxisome proliferator-activated receptor (PPAR)alpha, beta (also known as delta), and gamma function as sensors for fatty acids and fatty acid derivatives and control important metabolic pathways involved in the maintenance of energy balance. PPARs also regulate other diverse biological processes such as development, differentiation, inflammation, and neoplasia. In the nucleus, PPARs exist as heterodimers with retinoid X receptor-alpha bound to DNA with corepressor molecules.

Transcription coactivator PBP/MED1-deficient hepatocytes are not susceptible to diethylnitrosamine-induced hepatocarcinogenesis in the mouse.

Nuclear receptor coactivator [peroxisome proliferator-activated receptor-binding protein (PBP)/mediator subunit 1 (MED1)] is a critical component of the mediator transcription complex. Disruption of this gene in the mouse results in embryonic lethality. Using the PBP/MED1 liver conditional null (PBP/MED1(DeltaLiv)) mice, we reported that PBP/MED1 is essential for liver regeneration and the peroxisome proliferator-activated receptor alpha ligand Wy-14,643-induced receptor-mediated hepatocarcinogenesis.

Conditional ablation of mediator subunit MED1 (MED1/PPARBP) gene in mouse liver attenuates glucocorticoid receptor agonist dexamethasone-induced hepatic steatosis.

Glucocorticoid receptor (GR) agonist dexamethasone (Dex) induces hepatic steatosis and enhances constitutive androstane receptor (CAR) expression in the liver. CAR is known to worsen hepatic injury in nonalcoholic hepatic steatosis. Because transcription coactivator MED1/PPARBP gene is required for GR- and CAR-mediated transcriptional activation, we hypothesized that disruption of MED1/PPARBP gene in liver cells would result in the attenuation of Dex-induced hepatic steatosis.

Mechanisms of hepatic steatosis in mice fed a lipogenic methionine choline-deficient diet.

The methionine choline-deficient (MCD) diet results in liver injury similar to human nonalcoholic steatohepatitis (NASH). The aims of this study were to define mechanisms of MCD-induced steatosis in insulin-resistant db/db and insulin-sensitive db/m mice. MCD-fed db/db mice developed more hepatic steatosis and retained more insulin resistance than MCD-fed db/m mice.

Simvastatin causes the formation of cholesterol-rich remnants in mice lacking apoE.

Mice that lack apolipoprotein E (apoE) display a severe hypercholesterolemia, caused by the accumulation of apolipoprotein B-48 (apoB-48)-carrying remnants of chylomicrons and very-low-density lipoproteins in the plasma. Statins are potent inhibitors of cholesterol synthesis that, when administered to mice lacking apoE, cause paradoxical further increases in plasma cholesterol levels. In the present study, we examined the mechanisms responsible for this phenomenon.

Enhanced abdominal aortic aneurysm in TIMP-1-deficient mice.

Background: Matrix metalloproteinases (MMPs) are known elastolytic mediators of abdominal aortic aneurysm (AAA) degeneration, and their activity is tightly regulated by the presence of tissue inhibitors of MMPs (TIMPs). Imbalances in this system may be instrumental in compromising arterial wall integrity. The aim of this study was to show that, in an elastase-induced murine model of aneurysm formation, TIMP-1 has a protective effect.

The peroxisome proliferator-activated receptor alpha (PPARalpha) agonist ciprofibrate inhibits apolipoprotein B mRNA editing in low density lipoprotein receptor-deficient mice: effects on plasma lipoproteins and the development of atherosclerotic lesions.

Low density lipoprotein receptor (LDLR)-deficient mice fed a chow diet have a mild hypercholesterolemia caused by the abnormal accumulation in the plasma of apolipoprotein B (apoB)-100- and apoB-48-carrying intermediate density lipoproteins (IDL) and low density lipoproteins (LDL). Treatment of LDLR-deficient mice with ciprofibrate caused a marked decrease in plasma apoB-48-carrying IDL and LDL but at the same time caused a large accumulation of triglyceride-depleted apoB-100-carrying IDL and LDL, resulting in a significant increase in plasma cholesterol levels. These plasma lipoprotein changes were associated with an increase in the hepatic secretion of apoB-100-carrying very low density lipoproteins (VLDL) and a decrease in the secretion of apoB-48-carrying VLDL, accompanied by a significant decrease in hepatic apoB mRNA editing.

Salmonella enterica serovar Typhimurium requires nonsterol precursors of the cholesterol biosynthetic pathway for intracellular proliferation.

We have previously shown that Salmonella enterica serovar Typhimurium infection perturbs the host cholesterol biosynthetic pathway. Here we show that inhibiting the first step of this pathway (3-hydroxy-3-methylglutaryl coenzyme A reductase) reduces the growth of intracellular S. enterica serovar Typhimurium and has no effect on extracellular bacterial growth.

Overexpression of SR-BI by adenoviral vector reverses the fibrateinduced hypercholesterolemia of apolipoprotein E-deficient mice.

The hypercholesterolemia characteristic of apolipoprotein (apoE)-deficient mice fed on a regular chow diet is caused by the abnormal accumulation of apoB-48-carrying remnants of chylomicrons and very low density lipoproteins in the plasma. Treatment of apoE-deficient mice with ciprofibrate or other peroxisome proliferator-activated receptor alpha agonists severely aggravates their hypercholesterolemia by interfering with one or more mechanisms of remnant removal from the circulation that do not require mediation by apoE (Fu, T., Kashireddy, P.

Pigment epithelium-derived factor regulates the vasculature and mass of the prostate and pancreas.

Angiogenesis sustains tumor growth and metastasis, and recent studies indicate that the vascular endothelium regulates tissue mass. In the prostate, androgens drive angiogenic inducers to stimulate growth, whereas androgen withdrawal leads to decreased vascular endothelial growth factor, vascular regression and epithelial cell apoptosis. Here, we identify the angiogenesis inhibitor pigment epithelium-derived factor (PEDF) as a key inhibitor of stromal vasculature and epithelial tissue growth in mouse prostate and pancreas.

The peroxisome-proliferator-activated receptor alpha agonist ciprofibrate severely aggravates hypercholesterolaemia and accelerates the development of atherosclerosis in mice lacking apolipoprotein E.

Mice lacking apolipoprotein E (apoE) are characterized by severe hypercholesterolaemia, caused by an abnormal accumulation of apolipoprotein B-48 (apoB-48)-carrying remnants of chylomicrons and very-low-density lipoproteins (VLDL) in the plasma, and by the spontaneous development of atherosclerotic lesions. Ciprofibrate is a hypolipidaemic compound that acts primarily by enhancing the oxidation of fatty acids in the liver and, consequently, decreasing the production of hepatic VLDL. In the present study, homozygous apoE-deficient mice were fed with a normal chow diet, supplemented with ciprofibrate.

Macrophage uptake of low-density lipoprotein bound to aggregated C-reactive protein: possible mechanism of foam-cell formation in atherosclerotic lesions.

Foam cells found in atherosclerotic lesions are believed to derive from macrophages that take up aggregated low-density lipoprotein (LDL) particles bound to the extracellular matrix of arterial walls. C-reactive protein (CRP) is an acute-phase protein found in atherosclerotic lesions, which when immobilized on a solid phase, can bind and cluster LDL particles in a calcium-dependent manner. In the present study, we examined whether CRP-bound aggregated LDL could be taken up by macrophages in culture.

Prediction of 24-hour protein excretion in pregnancy with a single voided urine protein-to-creatinine ratio.

Objective: This study was undertaken to validate the prediction of 24- hour urine protein excretion by a single voided urine protein-to-creatinine (P:C) ratio in a hospitalized pregnant population at our institution. We sought to evaluate the ability of serial single voided P:C ratios to follow the course of proteinuria.

Study Design: Pregnant patients who were admitted to the antepartum unit at Northwestern Memorial Hospital and who were undergoing a 24-hour urine collection for the quantitation of proteinuria were recruited.

Circulating cardiac troponin I levels in Kawasaki disease.

In addition to the vascular findings of Kawasaki disease (KD), clinical, electrocardiographic, and/or echocardiographic signs of myocarditis are recognizable in the acute phase of KD in many patients. The mechanism of myocarditis and an association with the development of subsequent coronary artery abnormalities in KD is unknown. Previous studies of serum cardiac troponin I (cTnI) measurements in pediatric populations have suggested a possible utility of measurements in diagnosis and follow-up of KD.

Plasma clearance and liver uptake of chylomicron remnants generated by hepatic lipase lipolysis: evidence for a lactoferrin-sensitive and apolipoprotein E-independent pathway.

Chylomicrons labeled with [3H]cholesterol and [14C]triglyceride fatty acids were lipolyzed by hepatic lipase (HL) in vitro and then injected intravenously into normal mice fed low- or high-fat diets, and into apolipoprotein (apo) E-deficient mice. In normal mice fed the high-fat diet and injected with non-lipolyzed chylomicrons, the plasma clearance and hepatic uptake of the resulting [3H]cholesterol-labeled remnants was markedly inhibited. In contrast, chylomicrons lipolyzed by HL were taken up equally rapidly by the livers of mice fed the low- and high-fat diets.

Binding of fatty acid ethyl esters to albumin for transport to cells in culture.

Fatty acid ethyl esters (FAEE) are non-oxidative products of ethanol metabolism that have been proposed to mediate pathological changes in various organs and tissues resulting from excessive ethanol consumption. Evidence supporting this proposal is scant, however, mainly because of the lack of adequate methods with which to solubilize the highly hydrophobic FAEE in aqueous medium for testing under physiological conditions. In this report we describe a simple and practical method for solubilizing FAEE in aqueous medium by binding them to albumin.

Fatty acid ethyl ester synthesis by the isolated perfused rat heart.

Fatty acid ethyl esters (FAEEs), nonoxidative by-products of ethanol metabolism, are found in various tissues and plasma after ethanol ingestion and may be responsible for some of the pathological changes observed in alcohol-consuming individuals. Previous studies demonstrated that several different enzymes, including lipoprotein lipase (LPL), can catalyze FAEE synthesis in vitro. We report that LPL catalyzes FAEE synthesis in isolated rat hearts perfused with chylomicrons in the presence of ethanol.

The role of lipoprotein lipase and apoprotein E in the recognition of chylomicrons and chylomicron remnants by cultured isolated mouse hepatocytes.

Lipoprotein lipase (LPL) has been proposed to play a role in the uptake of chylomicron remnants by hepatocytes by mediating the binding of these lipoproteins to cell-surface glycosaminoglycans and to the low-density-lipoprotein receptor-related protein (LRP). This proposal is based on studies that examined the binding of chylomicrons to HepG2 cells, fibroblasts and Chinese hamster ovary cells in culture, in the presence of large amounts of LPL [Beisiegel (1995) Curr. Opin.

Uptake of chylomicron remnants and hepatic lipase-treated chylomicrons by a non-transformed murine hepatocyte cell line in culture.

AML 12 is a recently established differentiated, non-transformed hepatocyte cell line derived from mice transgenic for transforming growth factor alpha (Wu et al. (1994) Proc. Natl.

Mild dyslipidemia in mice following targeted inactivation of the hepatic lipase gene.

In order to gain better understanding of the function of hepatic lipase (HL) in vivo, we have generated mice that lack HL using gene targeting in embryonic stem cells. No mRNA for HL was detected in the liver of homozygous mutants, and no HL activity was detected in their plasma. Total cholesterol levels in plasma of mutant mice were increased by about 30% compared with wild type animals.