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PubMedDate not supplied

The fate of the orally administered bile acid sequestrant, polidexide, in humans.

1. The metabolic fate of the insoluble bile acid sequestrant polidexide, (poly-[2-(diethylamino)ethyl] polyglycerylenedextran hydrochloride), was studied in four adult humans following the oral administration of the 14C-labelled substance. 2. The mean cumulative recovery of 14C in faeces was 95-3% (s.e.m. = 1-1) of the administered dose, while mean cumulative recovery in urine was 0-37% (s.e.m. = 0-13) of the oral dose. 3. Only background levels of radioactivity were detectable in plasma samples taken 1-3 days after administration of tracer. 4. The findings suggested that polidexide was not absorbed from the gastrointestinal in man to any significant degree.

Adult↗
PubMed1977

Effects of colestipol hydrochloride and neomycin sulfate on cholesterol turnover in the rat.

Three groups of male rats were fed diets containing the bile acid sequestrant colestipol hydrochloride (1%), neomycin sulfate (0.25%), or basic diet during the test. After 15 days, each rat was injected IV with 3.9 muCi cholesterol-1,2(-3)H complexed with serum lipoproteins; specific radioactivity of the total serum cholesterol was measured at several time intervals for a period of 7 weeks. Computer analysis of the data indicated that the turnover of cholesterol could best be fitted by a three-pool model. In pool 1, colestipol HC1 caused a significant increase in production rate (10.09 to 15.96 mg/day) and the excretion rate constant (0.53 to 0.79 day-1) of cholesterol without significantly altering the size of the pool or serum cholesterol concentrations. These results are compatible with an agent capable of binding bile acids in the rat but do not cause a decrease of the sterol pool because of an adequate compensatory increase in cholesterol biosynthesis. Neomycin SO4 caused a significant reduction in serum cholesterol (9%) without altering turnover parameters and apparently exerts its hypocholesterolemia by some mechanism other than bile acid sequestration.

Animals↗
PubMed2025

The Effect of Colesevelam on the Microbiome in Postoperative Crohn's Disease.

BACKGROUND: While surgery plays a pivotal role in the management of ileal Crohn's disease, the risk of endoscopic recurrence following an ileocaecal resection can be greater than 65% within 12 months of surgery. More than 90% of patients with Crohn's disease have a concomitant diagnosis of bile acid diarrhea following an ileal resection. This pilot study aimed to assess whether the use of bile acid sequestrants in patients with Crohn's disease who have undergone a primary terminal ileal resection with concomitant bile acid diarrhea can alter the microbiome and prevent disease recurrence. METHODS: Patients with Crohn's disease who underwent a primary terminal ileal resection and had symptoms of diarrhea within 1-3 months of surgery underwent 75SeHCAT testing for bile acid diarrhea. If positive (75SeHCAT&#x2005;&#x2264;&#x2005;15%), patients were treated with colesevelam and stool samples were collected at 4 weeks, 8 weeks, and 6-12 months posttreatment. If negative (75SeHCAT&#x2005;>&#x2005;15%), treatment was not given and were reviewed in the clinic as per local guidelines. All patients underwent a 6-12 month postoperative colonoscopy where further stool samples and mucosal biopsies were taken. Disease activity was established using the endoscopic Rutgeert's score, with disease remission defined as Rutgeert's score <i2 and disease recurrence &#x2265;i2. 16S ribosomal RNA gene analysis was undertaken for the collected fecal and mucosal samples to assess &#x3b1;/&#x3b2;-diversity and microbial composition. RESULTS: A total of 14 patients who completed the study, 10 of whom had a 75SeHCAT positive diagnosis of bile acid diarrhea and were started on treatment with colesevelam. Four patients did not require treatment as 3 were asymptomatic and 1 had a negative 75SeHCAT scan. Three of the fourteen patients had disease recurrence at their 6-12 month postoperative colonoscopy assessment, of which 1 patient was taking colesevelam and 2 patients were not taking colesevelam. A total of 44 fecal samples and 44 mucosal biopsies underwent 16S ribosomal RNA gene analysis to assess &#x3b1;/&#x3b2;-diversity and microbial composition. In the colesevelam treated patients there was no significant difference in &#x3b1;/&#x3b2;-diversity pre- and posttreatment. Pretreatment, the 3 most abundant bacterial classes in all patients were Bacteroidia, Clostridia, and Gammaproteobacteria. Following 6-12 months of treatment, out of the 9 patients on colesevelam, 5/9 (55.6%) had a reduction in Bacteroidia, 9/9 (100%) had an increase in Clostridia, and 7/9 (77.8%) had a reduction in Gammaproteobacteria. Of the 2 patients not given colesevelam, one showed a reduction in Bacteroidia, increase in Clostridia and a reduction in Gammaproteobacteria. CONCLUSIONS: This small pilot study demonstrated that patients who were given colesevelam, were more likely to be in disease remission at their 6-12 months colonoscopy review compared with those not treated. Furthermore, treatment with colesevelam may have a role in altering the microbiome to help maintain remission states in postoperative Crohn's disease. Larger mechanistic studies are now needed to confirm these findings and demonstrate statistical significance as well as investigate whether this benefit may be present even in those patients with 75SeHCAT negative disease.

Humans↗
PubMed1978

Prevalence of gallstones in hyperlipidemia and incidence during treatment with clofibrate and/or cholestyramine.

The present study provides no evidence that the prevalence of gallstones is increased in patients with hyperlipidemia. During the first year of treatment with clofibrate, the incidence of new gallstones appears to increase 8-fold. Cholestyramine, in doses of 16 g per day, does not seem to increase the incidence of stones, either when given alone or with clofibrate. Further studies on the cumulative risk of clofibrate and the long-term effect of clofibrate on biliary lipid composition are necessary to adequately define the risk/benefit ratio of this medication--with or without bile acid sequestrants. It is highly desirable to ascertain whether the concurrent administration of agents such as chenodeoxycholic or ursodeoxycholic acids could beneficially affect bile lipid composition and hence protect against gallstone formation during the initial period of clofibrate treatment.

Cholelithiasis↗
PubMed1975

Effect of dietary fibre on gallstone formation in hamsters.

This study aimed at investigating the effect of different sources of dietary fibre on gallstone formation in hamsters. The substances studied were pectin, lignin and psyllium hydrocolloid. The two latter compounds protected hamsters against cholesterol gallstone formation. Lignin resulted in a decrease of the deoxycholic acid conentration and in a rise of the cholic/chenodeoxycholic acid ratio. These changes which are similar to those observed with cholestyramine suggest that lignin acts as a bile acid sequestrant. Psyllium hydrocolloid effected a similar shift of the cholic/chenodeoxycholic acid ratio but it also resulted in a rise of the deoxycholic concentration. This latter finding is not compatible with a bile acid sequestering role of this compound. The addition of alcohol to the drinking-water resulted in the formation of stones rich in pigment. Under these conditions the tendency to form such stones was not checked by either of the investigated substances.

Animals↗
PubMed1978

Characterization of the microsomal steroid-8-ene isomerase of cholesterol biosynthesis.

Rat liver microsomes contain an enzyme that catalyzes the isomerization of the nuclear double bond of steroids from the 8(9) position to the 7(8) position. The enzyme is most active with zymosterol, 5alpha-cholesta-8,24-dien-3beta-ol, which is a precursor of cholesterol. Properties of the microsomal isomerase have now been studied, and preliminary data are reported on both regulation of enzymic activity and first steps in the solubilization of the enzyme from membranes. After a brief lag period, the velocity of isomerase is relatively constant for about 5 min of incubation, and then isomerization subsides. The apparent Michaelis constant (52-70 micro M) is difficult to determine accurately, due to these complex kinetic changes. V(max) is 4.0-4.7 nmol/min per mg of microsomal protein. The apparent specific activity is more than ten times that of liver microsomal methyl sterol oxidase. The maximal specific activity of microsomal isomerase is approximately doubled when rats are fed an intestinal bile acid sequestrant, cholestyramine. Changes in specific activity of isomerase parallel changes in activities of other microsomal enzymes of cholesterol biosynthesis, such as 3-hydroxy-3-methylglutaryl-CoA reductase and 4-methyl sterol oxidase. Isomerase activity is destroyed by phospholipase A digestion, high concentration of bile salts, and solvent extraction, all of which are known either to remove phospholipid or to alter microsomal membrane integrity. On the other hand, isomerase remains active in the presence of a mild, nonionic detergent, Triton WR-1339; thus, solubilization with nonionic detergents is under study.

Animals↗
PubMed1976

Nonisotopic method for estimating cholesterogenesis in the rat.

Influence of several compounds on sterol production was determined from serum desmosterol (D) levels in rats treated with U-18666A:3beta-(2-diethylaminoethoxy) androst-5-en-17-one HCl. U-18666A blocks biosynthesis of cholesterol (C) by inhibiting conversion from D to C. Diets containing C (2%), the bile acid sequestrant colestipol HCl (1%), clofibrate (0.2%), combination of colestipol HCl and clofibrate, or basal diet were fed to normal or U-18666A (3 mg/kg/d) mald rats for 2 weeks. In normal rats, C feeding increased serum C levels (39%), colestipol HC l had no significant effect, while clofibrate or the combination with colestipated rats, C feeding reduced D concentration (30 to 13 mg/dl) indicating inhibition of synthesis via negative feedback system. Colestipol HCl increased D level (33%) and reduced C (60%) indicating increased synthesis; results are compatible with an agent capable of binding bile acids in the rat which can compensate for loss of these acids by increasing sterol synthesis. Compared to control, clofibrate reduced serum C (33%) and D (43%); in combination with colestipol HCl it inhibited the increased synthesis caused by the latter. Clofibrate appears to be an inhibitor of C biosynthesis. Also, tests with other compounds make it apparent that the U-18666A-treated rat model system can be useful in evaluating cholesterogenesis.

Androstenes↗
PubMed1976

Colestipol in familial type II hyperlipoproteinemia: a three-year trial.

Colestipol, a new bile acid sequestrant polymer, has been shown to lower the serum cholesterol level more than 30% in 13 patients with familial type II hyperlipoproteinemia. Placebo for 6 wk was followed by colestipol for periods up to 36 mo. A slight but not significant increase of serum triglyceride concentrations was observed during the first 18 no, but they returned to values under the baseline level thereafter. No signs of impaired intestinal fat resorption were noted. Side effects were primarily gastrointestinal (mild and transient constipation). Colestipol seems to be an effective and safe drug in the treatment of the famiial type II hyperlipoproteinemia, without escape phenonmenon.

Adolescent↗
PubMedDate not supplied

Clofibrate-induced low density liporotein elevation. Therapeutic implications and treatment by colestipol resin.

Plasma lipid and lipoprotein responses to clofibrate were assessed in fifteen hypertriglyceridemic patients for the purpose of ascertaining low-density lipoprotein (LDL) changes. Subjects were grouped into either Type IV (11) or IIB (4) subgroups according to initial LDL level. Clofibrate was without effect on LDL in the IIB group, but consistent, often large, elevations were noted in Type IV cases (mean increase, 37.6%, P less than 0.001). In the IIB subgroup, addition of the bile-acid sequestrant, colestipol, lowered LDL (27.8%, P less 0.02) and total cholesterol (21.3%, P less 0.01) below pre-treatment values. In the Type IV subgroup, LDL fell to 19.5% above baseline (P great than 0.05). Significant LDL elevations induced by clofibrate in three of six subjects were restored to initial levels. In both groups, triglycerides and very-low density lipoproteins (VLDL) were not affected. The efficacy of colestipol in reducing LDL levels, expressed as either absolute or percentage reductions, increased as a function of increasing post-clofibrate LDL concentration (r = 0.84, P less than 0.001). In these subjects the level of LDL after treatment with clofibrate depended upon their LDL level prior to drug therapy, the effect of clofibrate on this level, and lipoprotein phenotype. Thus colestipol was most effective in IIB subjects, Type IV subjects with the lowest baseline VLDL and hence reciprocally highest LDL, and Type IV individuals who exhibited the largest LDL induction by clofibrate. The reported ineffectiveness of clofibrate on mortality and morbidity in patients with established coronary heart disease might be related to elevations and infrequent reductions of LDL. From the perspective of lipoprotein lowering, the combination with colestipol appears more favorable.

Adult↗
PubMedDate not supplied

Results of colestipol therapy in Type II hyperlipoproteinemia.

Twenty-five patinets with well defined Type ii hyperlipoproteinemia were treated with a divided 15 g daily dose of colestipol, a bile acid sequestrant, for periods of up to 20 months. The patients were divided into 3 groups: Those with no obvious sequelae, those with arcus corneae, xanthomas, and/or xanthelasmas only, and those with atherosclerotic complications. Colestipol lowered plasma cholesterol in all 3 groups, but reduced it to normal or near-normal levels in only 9 of the 25 patients (36%). The response of plasma triglycerides was highly varible; the mean for each group was elevated by the drug. Colestipol was well-tolerated and its effect did not diminish with time. It is a useful drug in the treatment of hypercholesterolemia.

Adolescent↗
PubMed1979

The effects of cholestyramine on high density lipoprotein metabolism.

This study on 4 type II hyperlipoproteinaemic subjects examines the effects of pharmacologic doses (8 g twice daily) of the bile acid sequestrant cholestyramine on the plasma distribution and chemical composition of the high density lipoprotein subfractions, HDL2 and HDL3, and describes the influence of the drug on the metabolism of the major HDL aporoteins, apolipoprotein A-I and A-II. Cholestyramine lowered plasma low density lipoprotein cholesterol (32%; P less than 0.05) without affecting the level of that lipid in very low density or high density lipoproteins. However, the plasma HDL2/HDL3 ratio and apolipoprotein A-I concentration rose significantly on treatment, while apolipoprotein A-II remained unchanged. The rise in apolipoprotein A-I derived from an increase in its synthetic rate and produced a relative enrichment of the protein with respect to apolipoprotein A-II in both HDL subfractions. These results demonstrate the cholestyramine treatment affects HDL metabolism in a way which, according to current concepts, may prove beneficial to the recipient.

Apolipoproteins↗
PubMed1979

Use of combined diet and colestipol in long-term (7--7 1/2 years) treatment of patients with type II hyperlipoproteinemia.

Long-term effects of diet and colestipol (a bile acid sequestrant) were studied in 25 patients with familial type II hyperlipoproteinemia. Serum lipids and body weights of an initial group of 30 patients were stabilized by low cholesterol-saturated fat-refined carbohydrate diet and the patients were then randomized into placebo and drug-treatment groups. After explaining that the drug is nontoxic and effective in lowering serum lipids, total cholesterol (C) and low-density lipoprotein cholesterol (LDL-C), colestipol (30 g/day) and diet were given to the 25 patients who remained in the long-term follow-up program. The treatment resulted in highly significant lowering of serum lipids (mg/dl, mean +/- SEM): C and LDL-C from 412.7 +/- 24.4 and 331.1 +/- 22.8 to 270 +/- 11.0 and 188.1 +/- 13.8, respectively (p less than 0.001 in each instance) over 7--7 1/2 years. Although we observed no absolute increase in high density lipoprotein (HDL), the HDL/LDL ratio was elevated. Long-term colestipol and diet treatment reduced the xanthoma size and stabilized serially angiographically visualized atherosclerotic lesions in 21 of the 25 patients who showed a satisfactory hypolipemic response. It did not cause nutritional or metabolic disturbances.

Adult↗
PubMed1978

Thyroid hormone and thyrotropin levels in patients placed on colestipol hydrochloride.

Bile acid sequestrant resins can bind T4 in vitro and in the gut. Therefore, the effect of colestipol HCl on thyroid function was studied prospectively in 17 subjects with type II hyperlipoproteinemia. Serum T4, T3, T3 resin uptake, and TSH levels were measured before and during therapy. No change in T4 levels and only small transient, but significant, decreases in T3 were noted in a minority of patients; TSH levels did not change. Small increases in T3 resin uptake were noted. We conclude that no major alterations in thyroid function occurred with colestipol therapy.

Colestipol↗
PubMed2026

Machine Learning in Hyperlipidaemia Research: Screening and Experimental Insights into Lipid Metabolism Modulators.

Hyperlipidemia, characterized by elevated blood lipid levels, represents a major global health concern due to its strong association with cardiovascular disease, diabetes, and metabolic syndrome. While current therapies - such as statins, fibrates, bile acid sequestrants, and PCSK9 inhibitors - are effective in controlling hyperlipidemia, they are often associated with adverse effects, potential drug resistance, and suboptimal efficacy in certain patient populations. All of the above underscore the urgent need for safer and more effective therapeutic alternatives. Among the major molecular targets involved in the regulation of lipid metabolism are HMG-CoA reductase, PCSK9, peroxisome proliferator-activated receptors (PPARs), cholesteryl ester transfer protein (CETP), and nuclear receptors, including the liver X receptor (LXR) and farnesoid X receptor (FXR), which are also targets for future antihyperlipidemic drug development. Recent advancements in artificial intelligence (AI) and machine learning (ML) have significantly transformed and accelerated drug discovery by enabling the processing of vast amounts of genomic, proteomic, and chemical data. Furthermore, ML tools such as quantitative structure-activity relationship (QSAR) modelling, deep learning, random forest, and support vector machines (SVM) have proven predictive and effective in identifying novel lipid metabolism modulators, thereby enhancing the efficacy and accuracy of virtual screening. Meanwhile, molecular docking has become an integral part of structure-based drug design (SBDD), and software such as AutoDock, Glide, and GOLD have proven effective in generating accurate ligand-target docking models. Molecular docking, together with ML-based approaches, enables the identification of potent and selective drug candidates. Overall, the combination of ML and molecular docking offers an efficient and accurate platform for antihyperlipidemic drug discovery, helping to overcome the limitations of currently available therapeutic strategies.

HMG-CoA reductase↗
PubMed1975

Treatment of pruritus in cholestasis of pregnancy with a new anion exchange resin (Secholex).

Anion exchange resins form a non-absorbable complex with bile acids in the intestine, thus removing bile acids from the enterohepatic circulation and facilitating bile acid excretion in the faeces. A new bile acid sequestrant (PDX chloride, Secholex) was evaluated for the relief of pruritus in cholestasis of pregnancy (CP) in 31 women. CP was verified by the presence of the abnormal lipoprotein X in serum and the clinical series was divided into two degrees of severity, pruritus gravidarum (PG) and hepatosis of pregnancy (HP) based on liver function tests. Eleven of 31 women discontinued treatment because of gastro-intestinal side effects. Of the 20 women continuing the study for more than one week, all with a milder form of cholestasis, PG (n=8), experienced relief of pruritus, while some relief was obtained in 75% of the women with HP. After up to 4 weeks administration of Secholex, no obvious interference with fat absorption was evident judging from the serum lecithin content of linoleic and arachidonic acids. A reduction in serum folic acid might indicate an interaction in folic acid absorption. An expected reduction in serum cholesterol levels which are characteristically increased in CP, was not achieved by the administration of Secholex.

Anion Exchange Resins↗