Absorption, distribution and excretion of GT31-104, a novel bile acid sequestrant, in rats and dogs after acute and subchronic administration

The Novel Phosphate and Bile Acid Sequestrant Polymer SAR442357 Delays Disease Progression in a Rat Model of Diabetic Nephropathy

As a gut-restricted, nonabsorbed therapy, polymeric bile acid sequestrants (BAS) play an important role in managing hyperlipidemia and hyperglycemia. Similarly, nonabsorbable sequestrants of dietary phosphate have been used for the management of hyperphosphatemia in end-stage renal disease. To evaluate the potential utility of such polymer sequestrants to treat type 2 diabetes (T2D) and its associated renal and cardiovascular complications, we synthesized a novel polymeric sequestrant, SAR442357, possessing optimized bile acid (BA) and phosphate sequestration characteristics. Long-term treatment of T2D obese ^cZucker fatty/Spontaneously hypertensive heart failure F1 hybrid (ZSF1) with SAR442357 resulted in enhanced sequestration of BAs and phosphate in the gut, improved glycemic control, lowering of serum cholesterol, and attenuation of diabetic kidney disease (DKD) progression. In comparison, colesevelam, a BAS with poor phosphate binding properties, did not prevent DKD progression, whereas losartan, an angiotensin II receptor blocker that is widely used to treat DKD, showed no effect on hyperglycemia. Analysis of hepatic gene expression levels of the animals treated with SAR442357 revealed upregulation of genes responsible for the biosynthesis of cholesterol and BAs, providing clear evidence of target engagement and mode of action of the new sequestrant. Additional hepatic gene expression pathway changes were indicative of an interruption of the enterohepatic BA cycle. Histopathological analysis of ZSF1 rat kidneys treated with SAR442357 further supported its nephroprotective properties. Collectively, these findings reveal the pharmacological benefit of simultaneous sequestration of BAs and phosphate in treating T2D and its associated comorbidities and cardiovascular complications. SIGNIFICANCE STATEMENT: A new nonabsorbed polymeric sequestrant with optimum phosphate and bile salt sequestration properties was developed as a treatment option for DKD. The new polymeric sequestrant offered combined pharmacological benefits including glucose regulation, lipid lowering, and attenuation of DKD progression in a single therapeutic agent.

Goal achievement of HbA1c and LDL-cholesterol in a randomized trial comparing colesevelam with ezetimibe: GOAL-RCT

AIM

To compare the efficacy and safety of colesevelam and ezetimibe as second-line low density lipoprotein-cholesterol (LDL-c)-lowering options in type 2 diabetes (T2D).

MATERIALS AND METHODS

GOAL-RCT is a 24-week, open-label, randomized, pragmatic clinical trial. Subjects with T2D with uncontrolled HbA1c (7.1%-10%) and LDL-c (>2.0 mmol/L) were randomized 1:1 to colesevelam 3.75 g or ezetimibe 10 mg daily. The primary composite outcome was the proportion of participants achieving an LDL-c target of ≤2.0 mmol/L and HbA1c target of ≤7.0%. Intention to treat analysis was performed.

RESULTS

Two hundred subjects were enrolled: mean age 59 ± 10 years; mean HbA1c 8.0%; mean LDL-c 2.5 mmol/L; 97% on statin therapy. The primary composite outcome was achieved by similar proportions of participants with colesevelam (14.6%) and ezetimibe (10.5%) (P_{non-inferiority}  < .001, P_superiority = .41). LDL-c reduction from baseline was less with colesevelam compared with ezetimibe (14.0% vs. 23.2%, P < .01), as was the proportion of subjects achieving an LDL-c target of ≤2.0 mmol/L (47.6% and 67.0%, respectively; P = .007). Mean HbA1c was reduced with colesevelam (-0.26 ± 0.10%), while no change was observed with ezetimibe (difference P = .06). Adverse events and discontinuation rates were higher for colesevelam (20.2% and 31.1%) compared with ezetimibe (7.2% and 6.2%), respectively.

CONCLUSIONS

Among subjects with T2D, the initiation of colesevelam or ezetimibe led to similar achievement of primary composite outcome (LDL-c and HbA1c within target), with ezetimibe recording a greater LDL-c reduction and better tolerability than colesevelam.

The Role of the Gut Microbiota in Bile Acid Metabolism

The gut microbiota has been considered a cornerstone of maintaining the health status of its human host because it not only facilitates harvesting of nutrients and energy from ingested food, but also produces numerous metabolites that can regulate host metabolism. One such class of metabolites, the bile acids, are synthesized from cholesterol in the liver and further metabolized by the gut microbiota into secondary bile acids. These bioconversions modulate the signaling properties of bile acids through the nuclear farnesoid X receptor and the G protein-coupled membrane receptor 5, which regulate diverse metabolic pathways in the host. In addition, bile acids can regulate gut microbial composition both directly and indirectly by activation of innate immune response genes in the small intestine. Therefore, host metabolism can be affected by both microbial modifications of bile acids, which leads to altered signaling via bile acid receptors, and by alterations in the composition of the microbiota. In this review, we mainly describe the interactions between bile acids and intestinal microbiota and their roles in regulating host metabolism, but we also examine the impact of bile acid composition in the gut on the intestinal microbiome and on host physiology.

Bile acid sequestrants for glycemic control in patients with type 2 diabetes: A systematic review with meta-analysis of randomized controlled trials

AIM

To evaluate the effects of bile acid sequestrants (BASs) versus placebo, no intervention or active comparators on glycemic control in type 2 diabetes.

METHODS

Data were retrieved and a systematic review with meta-analyses was performed. We evaluated bias control and subgroup and sensitivity analyses were performed to evaluate heterogeneity and bias.

RESULTS

We included 17 trials with a total of 2950 patients randomized to BASs (colesevelam or colestimide) versus placebo, no intervention, statins or sitagliptin. Random-effects meta-analysis showed that patients randomized to BASs had a lower hemoglobin A_1c at the end of treatment compared with the control group (mean difference-0.55%; 95% confidence interval-0.64 to -0.46). Analysis of trials with low risk of bias in all domains confirmed the findings. Data on adverse events were limited. There were no differences between trials stratified by the control group and no evidence of publication bias or small study effects.

CONCLUSIONS

Our analyses found that BAS treatment improves glycemic control. The size of the effect was clinically relevant and despite limited safety data, our findings support the inclusion of BASs in current diabetes management algorithms for type 2 diabetes.

Dietary Administration of Colesevelam Hydrochloride Does Not Affect Fertility or Reproductive Performance in Rats

Colesevelam hydrochloride (HCl) (WelChol; Sankyo Pharma) is a novel, highly potent, bile acid-binding polymer used for the treatment of hypercholesterolemia. The primary aim of this study was to determine the effects of dietarily administered colesevelam HCl on fertility and reproductive performance parameters. To assess these effects, sexually mature Sprague-Dawley rats were randomized to one of five treatment groups: feed alone, feed plus control article (SigmaCell), or feed plus colesevelam HCl 200, 1000, or 2000 mg/kg/day. Male and female rats were administered the appropriate group agent for 28 and 15 days, respectively, and were subsequently paired together for cohabitation and mating. Females continued to receive the test agent in their dietary formulation through presumed gestation day (GD) 7. Presumed pregnant females underwent cesarean section on GD 20. Food consumption rate, body weight, gross necropsy, and standard preclinical tests for reproduction and fertility were performed for each test animal. No statistically significant differences were found between control and drug-treated groups for any tested endpoints of reproduction. All animals placed in cohabitation successfully mated. Uterine and litter end points were unaffected by dosages of colesevelam HCl as high as 2000 mg/kg/day. There were no significant differences between treatment group litter averages in the number of corpora lutea, implantation sites, litter size, live fetuses, body weights, early/late resorptions, and the number of dams with viable fetuses. In addition, no external alterations of fetal morphology were attributable to treatment with colesevelam HCl when administered up to the embryo implantation stage. In male animals, no significant differences were found between the colesevelam HCl and control study groups in the average caudal epididymal sperm count or sperm concentration, total number of motile and nonmotile sperm, and the total percentage of motile sperm. Based on these data, colesevelam HCl does not have any significant adverse reproductive or fertility effects in rats, even when administered at doses approximately 30 times greater than the approved clinical dose.

Achieving glycemic control in elderly patients with type 2 diabetes: a critical comparison of current options

The prevalence of type 2 diabetes mellitus (T2DM) is increasing in the elderly. Because of the unique characteristics of elderly people with T2DM, therapeutic strategy and focus should be tailored to suit this population. This article reviews the guidelines and studies related to older people with T2DM worldwide. A few important themes are generalized: 1) the functional and cognitive status is critical for older people with T2DM considering their life expectancy compared to younger counterparts; 2) both severe hypoglycemia and persistent hyperglycemia are deleterious to older adults with T2DM, and both conditions should be avoided when determining therapeutic goals; 3) recently developed guidelines emphasize the avoidance of hypoglycemic episodes in older people, even in the absence of symptoms. In addition, we raise the concern of glycemic variability, and discuss the rationale for the selection of current options in managing this patient population.

Bile acid sequestrants: glucose-lowering mechanisms and efficacy in type 2 diabetes

Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid and glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption of the enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose-lowering effect in patients with type 2 diabetes remain unclear. This article offers a review of the mechanisms behind the glucose-lowering effect of BASs, and the efficacy of BASs in the treatment of type 2 diabetes.

Colesevelam for type 2 diabetes mellitus

BACKGROUND

Colesevelam is a second-generation bile acid sequestrant that has effects on both blood glucose and lipid levels. It provides a promising approach to glycaemic and lipid control simultaneously.

OBJECTIVES

To assess the effects of colesevelam for type 2 diabetes mellitus.

SEARCH METHODS

Several electronic databases were searched, among these The Cochrane Library (Issue 1, 2012), MEDLINE, EMBASE, CINAHL, LILACS, OpenGrey and Proquest Dissertations and Theses database (all up to January 2012), combined with handsearches. No language restriction was used.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared colesevelam with or without other oral hypoglycaemic agents with a placebo or a control intervention with or without oral hypoglycaemic agents.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the trials and extracted the data. We evaluated risk of bias of trials using the parameters of randomisation, allocation concealment, blinding, completeness of outcome data, selective reporting and other potential sources of bias.

MAIN RESULTS

Six RCTs ranging from 8 to 26 weeks investigating 1450 participants met the inclusion criteria. Overall, the risk of bias of these trials was unclear or high. All RCTs compared the effects of colesevelam with or without other antidiabetic drug treatments with placebo only (one study) or combined with antidiabetic drug treatments. Colesevelam with add-on antidiabetic agents demonstrated a statistically significant reduction in fasting blood glucose with a mean difference (MD) of -15 mg/dL (95% confidence interval (CI) -22 to - 8), P < 0.0001; 1075 participants, 4 trials, no trial with low risk of bias in all domains. There was also a reduction in glycosylated haemoglobin A1c (HbA1c) in favour of colesevelam (MD -0.5% (95% CI -0.6 to -0.4), P < 0.00001; 1315 participants, 5 trials, no trial with low risk of bias in all domains. However, the single trial comparing colesevelam to placebo only (33 participants) did not reveal a statistically significant difference between the two arms - in fact, in both arms HbA1c increased. Colesevelam with add-on antidiabetic agents demonstrated a statistical significant reduction in low-density lipoprotein (LDL)-cholesterol with a MD of -13 mg/dL (95% CI -17 to - 9), P < 0.00001; 886 participants, 4 trials, no trial with low risk of bias in all domains. Non-severe hypoglycaemic episodes were infrequently observed. No other serious adverse effects were reported. There was no documentation of complications of the disease, morbidity, mortality, health-related quality of life and costs.

AUTHORS' CONCLUSIONS

Colesevelam added on to antidiabetic agents showed significant effects on glycaemic control. However, there is a limited number of studies with the different colesevelam/antidiabetic agent combinations. More information on the benefit-risk ratio of colesevelam treatment is necessary to assess the long-term effects, particularly in the management of cardiovascular risks as well as the reduction in micro- and macrovascular complications of type 2 diabetes mellitus. Furthermore, long-term data on health-related quality of life and all-cause mortality also need to be investigated.

Colesevelam hydrochloride: evidence for its use in the treatment of hypercholesterolemia and type 2 diabetes mellitus with insights into mechanism of action

Colesevelam hydrochloride is a molecularly engineered, second-generation bile acid sequestrant demonstrating enhanced specificity for bile acids which has been approved for use as adjunctive therapy to diet and exercise as monotherapy or in combination with a β-hydroxymethylglutaryl-coenzyme A reductase inhibitor for the reduction of elevated low-density lipoprotein cholesterol in patients with primary hypercholesterolemia. It is also the only lipid-lowering agent currently available in the United States which has been approved for use as adjunctive therapy in patients with type 2 diabetes mellitus whose glycemia remains inadequately controlled on therapy with metformin, sulfonylurea, or insulin. With the recent emphasis upon drug safety by the Food and Drug Administration and various consumer agencies, it is fitting that the role of nonsystemic lipid-lowering therapies such as bile acid sequestrants – with nearly 90 years of in-class, clinically safe experience – should be reexamined. This paper presents information on the major pharmacologic effects of colesevelam, including a discussion of recent data derived from both in vitro and in vivo rodent and human studies, which shed light on the putative mechanisms involved.

Role of colesevelam in managing heterozygous familial hypercholesterolemia in adolescents and children

BACKGROUND

Colesevelam hydrochloride is a synthetic, nonsystemically absorbed polymer that functions as a bile acid sequestrant for the treatment of hypercholesterolemia. Recently, colesevelam was investigated for the treatment of heterozygous familial hypercholesterolemia (HeFH) in the pediatric/adolescent population aged 10-17 years.

OBJECTIVE

The purpose of this article is to review the disease state of HeFH in children and adolescents, review the pharmacologic mechanism of action, kinetics, and safety profile of colesevelam, analyze the results of a recent clinical trial of colesevelam in the pediatric/adolescent HeFH population, and discuss the role of colesevelam as a viable treatment option for HeFH.

METHODS

A literature search using Medline (1966-03 May 2010), PubMed (1950-03 May 2010), Science Direct (1994-03 May 2010), and International Pharmaceutical Abstracts (2004-2010) was performed using the search term colesevelam. English language, original research, and review articles were examined, and citations from these articles were also assessed. The manufacturer's prescribing information and the Food and Drug Administration review of the new drug application for the powder formulation were also examined.

RESULTS

A 32-week trial was performed investigating the efficacy of colesevelam as monotherapy or combination therapy with a stable statin regimen. Upon completion of the trial, significant benefits were found in regard to the treatment of HeFH and the lowering of low-density lipoprotein cholesterol, total cholesterol, and other secondary measures. Safety and tolerability were also examined throughout the duration of the clinical trial, with adverse drug reactions considered mild in severity.

CONCLUSION

Colesevelam has been shown to reduce low-density lipoprotein cholesterol levels significantly in pediatric/adolescent patients with HeFH, while maintaining a mild side effect profile. Although further research would be beneficial for long-term effects in this population, colesevelam should be considered when developing a treatment regimen for HeFH in the pediatric/adolescent population.

Colesevelam hydrochloride for the treatment of type 2 diabetes mellitus

BACKGROUND

Colesevelam hydrochloride is a bile acid sequestrant approved in January 2008 by the US Food and Drug Administration (FDA) for the treatment of adult patients with type 2 diabetes mellitus (DM) in combination with a sulfonylurea, metformin, and/or insulin therapy.

OBJECTIVE

The purpose of this article was to review the pharmacology, pharmacokinetics, efficacy, adverse effects and tolerability, drug-drug interactions, contraindications/precautions, dosage and administration, pharmacoeconomics, and the overall role of colesevelam in the management of adult patients with type 2 DM.

METHODS

A literature search using MEDLINE (1966-October 27, 2008), PubMed (1950-October 27, 2008), Science Direct (1994-October 27, 2008), Web of Science (1980-October 27, 2008), American Diabetes Association Scientific Abstracts (2004-2008), and International Pharmaceutical Abstracts (1970-October 27, 2008) was performed using the term colesevelam. English-language, original research and review articles were examined, and citations from these articles were assessed. Manufacturer prescribing information and the FDA review of the new drug application for colesevelam were also examined.

RESULTS

Colesevelam is a hydrophilic, water-insoluble polymer, with negligible absorption and systemic distribution, that is excreted primarily in the feces. Through a mechanism still under investigation, colesevelam effectively lowers glycosylated hemoglobin (HbA(1c)) when used in combination with a sulfonylurea, metformin, and/or insulin therapy. Three completed, published Phase III clinical trials investigating colesevelam for the treatment of type 2 DM were evaluated for information, data, and conclusions. At dosing of 1.875 g BID or 3.75 g once daily in combination with one of the aforementioned agents versus placebo, reductions in HbA(1c) in all 3 Phase III clinical trials of colesevelam ranged from 0.5% to 0.7% (P < 0.02). In clinical trials, colesevelam was well tolerated, with hypoglycemia occurring in approximately 3% of studied patients.

CONCLUSIONS

When used in combination with a sulfonylurea, metformin, and/or insulin therapy, colesevelam has been reported to significantly reduce HbA(1c) in adult patients with type 2 DM. Colesevelam's role in the management of type 2 DM remains undefined, however; further investigation into its mechanism of action and long-term efficacy and safety should be performed.

Cholesterol absorption inhibitors as a therapeutic option for hypercholesterolaemia

The development of cholesterol-lowering drugs (including a variety of statins, bile acid-binding resins and recently discovered inhibitors of cholesterol absorption) has expanded the options for cardiovascular prevention. Recent treatment guidelines emphasise that individuals at substantial risk for atherosclerotic coronary heart disease should meet defined targets for LDL cholesterol concentrations. Combination therapy with drugs that have different or complementary mechanisms of action is often needed to achieve lipid goals. Existing approaches to the treatment of hypercholesterolaemia are still ineffective in halting the progression of coronary artery disease in some patients despite combination therapies. Other patients are resistant to conventional drug treatment and remain at high risk for the development and progression of atherosclerotic cardiovascular disease and alternative approaches are needed. The discovery and development of ezetimibe (a novel, selective and potent cholesterol absorption inhibitor) has advanced the treatment of hypercholesterolaemia. New agents including the phytostanol preparation FM-VP4 and inhibitors of acyl coenzyme A:cholesterol acyltransferase, the apical Na(+)-dependent bile acid transporter and microsomal triglyceride transfer protein may also play a future role in combination therapy. This review focuses on the recent progress in the molecular mechanisms of intestinal cholesterol absorption and transport, and novel therapeutic approaches to inhibit the cholesterol absorption process.

Colesevelam hydrochloride does not cause maternal or fetal toxicity in rats and rabbits

WelChol (colesevelam hydrochloride), a bile acid sequestrant for the treatment of hypercholesterolemia, was evaluated for adverse effects on reproduction and fetal development using standard preclinical tests. During gestation, Sprague-Dawley rats used in the developmental toxicity study received feed, feed/control article or feed plus 300, 1,000 or 3,000 mg/kg/day colesevelam whereas rats in the pre- and postnatal toxicity study received vehicle or 100, 300 or 1,000 mg/kg/day colesevelam via gavage. New Zealand white rabbits received control or 100, 500 or 1,000 mg/kg/day colesevelam via gavage. No deaths, premature deliveries or gross pathologic lesions were observed up to gestation day (GD) 20 for rats and GD 28 for rabbits. No significant differences in the number of pregnant animals, average litter size, percentage of viable fetuses, fetal body weights, number of corpora lutea, fetal viability, or gross malformations were observed versus controls. Pre- and postnatal effects were assessed in pregnant rats receiving 100, 300 or 1,000 mg/kg/day colesevelam from GD 6 to postpartum day 22. Gestation, parturition and lactation in F(0) generation dams were similar between treatment and control groups. Colesevelam did not affect physical or neurological development or induce gross pathological changes in F(1) generation rats. Colesevelam does not produce developmental toxicity in rats or rabbits, nor does it exhibit pre- or postnatal toxicity in rats at the tested doses.

Colesevelam hydrochloride: a novel bile acid-binding resin

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, and adverse effects of colesevelam hydrochloride, a bile acid-binding resin.

METHODS

MEDLINE searches (1966-June 2000) and manufacturer prescribing literature were employed to find articles on colesevelam. Additional studies and abstracts were identified from the bibliographies of reviewed literature.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from data sources were evaluated, and all information deemed relevant was included in this review. Priority was given to randomized, double-blind, placebo-controlled studies.

FINDINGS

Colesevelam HCl is a nonabsorbed hydrogel with bile acid sequestrant properties. Monotherapy using colesevelam in once-daily or two divided daily doses of 1.5-4.5 g has produced significant reductions in total cholesterol and low-density lipoprotein (LDL) cholesterol. Mean LDL cholesterol decreases to 20% have been noted when the patient is on 3.75-4.5 g/d. Increases in high-density lipoprotein (HDL) cholesterol have been observed (up to 9%), whereas triglycerides (TG) have increased significantly to 25% in some studies. In unpublished studies, combined use of colesevelam plus hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor have produced greater reductions in LDL cholesterol than either the statin or colesevelam administered alone. The efficacy of colesevelam monotherapy is slightly less than or similar to cholestyramine or colestipol in decreasing LDL cholesterol, although colesevelam is more potent on a gram-to-gram basis. Adverse effects have been minimal with colesevelam in published studies; this suggests an advantage over cholestyramine or colestipol therapy. Colesevelam appears to be more cost-effective than the packet dosage form of the brand formulation of the older bile acid resins. Care in selection of an appropriate agent should be exercised when considering the issues of adverse effects and palatability.

CONCLUSIONS

Colesevelam alone or combined with an HMG-CoA reductase inhibitor is effective in the reduction of total and LDL cholesterol. Since colesevelam is formulated as a tablet, problems with palatability such as with the powder formulation of the bile acid-binding resins are likely to be eliminated.

Colesevelam

Colesevelam, a bile acid sequestrant used in the treatment of patients with hypercholesterolemia, is a lipid-lowering polymer that has high affinity for bile acids. In animals colesevelam was not systemically absorbed after oral administration and was rapidly eliminated via the gastrointestinal tract. Colesevelam did not alter the serum concentrations or pharmacokinetic properties of drugs from several different classes in healthy volunteers. Colesevelam administered orally in patients with primary hypercholesterolemia significantly reduced serum levels of low density lipoprotein (LDL)-cholesterol and total cholesterol. This lipid-lowering activity was sustained during short (6 weeks) and longer term (24 weeks) treatment. Combination therapy with colesevelam plus hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (lovastatin, simvastatin or atorvastatin) was associated with additive reductions in serum levels of LDL-cholesterol and total cholesterol, relative to either agent alone. Colesevelam treatment was well tolerated and lacked severe gastrointestinal adverse events typical of other bile acid sequestrants (bloating, flatulence, heartburn and nausea). The most frequently reported adverse events were constipation and dyspepsia. In humans colesevelam did not induce clinically significant changes in serum levels of vitamins, coagulation parameters or liver enzymes.

Neither intestinal sequestration of bile acids nor common bile duct ligation modulate the expression and function of the rat ileal bile acid transporter

The regulatory responses of bile acid (BA) transport in the terminal ileum to perturbations in BA homeostasis are complex, and conflicting results have been reported by different investigators. These studies were designed to examine the response of this system to a reduction in ileal bile salt concentrations at both a functional and molecular level. Common bile duct ligation (BDL) or feeding of a novel bile acid-binding compound, GT31-104HB, for 7 days were used to reduce ileal apical membrane bile salt flux. Apical bile acid transport function was assessed by examining sodium-dependent uptake of [3H]-taurocholate (TC) into brush border membrane vesicles (BBMV). Expression of the apical sodium-dependent bile acid transporter (ASBT) and the ileal lipid-binding protein (ILBP) were assessed by Western blotting with quantitation using [125I]-labeled secondary antibody and a phosphorimager. Neither common BDL nor intestinal sequestration of BA led to a change in ileal bile acid transport function or the expression of the ASBT or the ILBP. These results indicate that a reduction in presentation of bile salts to the apical surface of the terminal ileum does not modulate the expression of the genes involved in their transport.