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PubMed2005

In vitro study of the adsorption characteristics of drugs.

The adsorption characteristics of eight adsorbents, cholestyramine, colestimide, aluminum silicate, sucralfate, aluminum hydroxide, calcium polystyrene sulfonate, carbon sphere and medicinal carbon, on the drugs such as methotrexate, antidepressants, mizoribine and ciprofloxacin hydrochloride were investigated in vitro. Medicinal carbon showed an excellent adsorption of all the tested drugs while the carbon spheres showed a high but slow adsorption characteristic. Cholestyramine and colestimide showed a higher adsorption in methotrexate than the other adsorbents. Aluminum silicate and calcium polystyrene sulfonate showed higher adsorption in four antidepressants, clomipramine hydrochloride, imipramine hydrochloride, mianserin hydrochloride and trazodone hydrochloride. In mizoribine, there were no adsorbents that showed higher adsorption except for the medicinal carbon. In ciprofloxacin hydrochloride, aluminum preparations and calcium polystyrene sulfonate showed higher adsorption characteristics. It is suggested that several adsorbents are potentially useful treatments for drug overdoses, but that these adsorbents have the possibility of decreasing the effects of the co-administered medicines.

Adsorption↗

PubMed2000

Studies on adsorption characteristics of bile acids and methotrexate to a new type of anion-exchange resin, colestimide.

The adsorption characteristics of various bile acids and methotrexate to a new type of anion-exchange resin, colestimide, were studied in vitro and compared with those to cholestyramine. For bile acids, colestimide was shown to have a higher capacity than cholestyramine. For example, approximately 1.4-fold higher for cholic acid and 2.0-fold for deoxycholic acid in water. In the presence of physiological anions, the degree of adsorption of cholic acid to both resins was greatly reduced, whereas adsorption of deoxycholic acid was only slightly reduced. Furthermore, the bed-volume of colestimide swelled about 6.8-fold in water, hence the anion-exchange groups of this resin are expected to be able to function effectively in adsorption of bile acids in the gut. In addition, colestimide was found to have high adsorption capacity for methotrexate, not only in water but also in media containing various physiological anions, and thus it is suggested that colestimide is a potential oral antidote to reduce possible toxicity by methotrexate through interruption of enterohepatic circulation.

Anion Exchange Resins↗

PubMedDate not supplied

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.

Adult↗

PubMed1997

Lack of deafness in Crigler-Najjar syndrome type 1: a patient survey.

We performed a questionnaire survey about 42 patients with Crigler-Najjar syndrome type 1 who were currently alive. Information was obtained on their age, sex, birth weight, gestation, parental consanguinity, other family members affected, age of onset of jaundice, neonatal and postneonatal bilirubin values, neonatal and postneonatal therapy, problems faced with phototherapy, liver transplantation, current growth status, current neurologic status, and the status of hearing. Patients were between 2 months and 21 years of age. There were 18 males and 24 females. Thirty-nine patients had been born at full term gestation and 3 had been preterm. Jaundice was noted on postnatal day 1 in 34%, between days 2 and 4 in 55%, and after day 11 of life in 11% of patients. In the neonatal period bilirubin values (mean +/- SD) were typically 19.8 +/- 4.5 mg/dL. Eighty-six percent of patients had neonatal peak bilirubin values of >20 mg/dL. Parental consanguinity was present in 44% and a history of Gilbert's disease in one parent was present in 10% of patients. Causes of exacerbations of jaundice reported were respiratory infections, febrile illnesses, vaccinations, fasting, surgery, emotional stress, and noncompliance with treatment. Neonatal therapy consisted of exchange transfusion in 28%, phototherapy in 79%, phenobarbitone in 20%, and cholestyramine, albumin, infusions, and plasmapheresis in one case each. The mainstay of postneonatal therapy was home phototherapy for 10 to 16 hours, primarily at night during sleep, using blue lights or a combination of blue and fluorescent lights. Some patients used innovatively designed phototherapy units. Problems reported with phototherapy were decreased effectiveness with age, poor compliance, restriction of activity and play, inability to travel or take vacations, irritation from eye shades, difficulty keeping eye protection on, difficulties in temperature maintenance, tanning of the skin, embarrassment from the need to be nearly nude during phototherapy, and difficulty in procuring phototherapy lamps. Other therapies that had been tried included oral agar, albumin infusions, antioxidants, acupuncture, bilirubin oxidase, calcium infusions, clofibrate, cruciferous vegetables, cholestyramine, chlorpromazine, flumecinol, plasmapheresis, tin mesoporphyrin, ursodeoxycholic acid, and urinary alkalinization. Fifteen children had undergone liver transplantation (5 auxiliary and 10 orthotopic). All 42 patients are reportedly of normal height and weight. Neurodevelopmental status is said to be normal in 77% of patients. Two patients have kernicterus, 4 have cerebellar symptoms, and 1 each has developmental delay, mild intention tremor, and mild speech delay. Hearing was reported to be normal in 94% of patients. The 2 children with hearing loss have conductive loss from otitis media. With home phototherapy prolonged, survival free of neurologic deficits is possible in Crigler-Najjar syndrome type 1, but there are many problems associated with phototherapy. Avoiding exacerbations of jaundice is an important aspect of management. Liver transplantation offers the prospect of cure but its risk versus benefit ratio is undetermined. Hearing loss was absent in the patients surveyed despite prolonged exposure to high bilirubin levels, which suggests that bilirubin may not be as ototoxic as is commonly believed.

Adolescent↗

PubMed1988

The future of pharmacological therapy for risk factor reduction. Hyperlipidaemia.

The European Atherosclerosis Society has produced guidelines for the drug treatment of hyperlipidaemia. This, of necessity, is lifelong and therefore should be prescribed only after exclusion of secondary causes for the disorder, after dietary advice has failed to produce desirable plasma lipid levels and after careful consideration of the individual case. A plasma lipid-lowering drug should be efficacious on a long term basis on plasma lipid levels, should fulfil conditions for long term compliance regarding simplicity of administration and lack of subjective side effects, have a documented effect on the clinical endpoint (e.g. myocardial infarction) and be safe on a long term basis. Based on these conditions, plasma lipid-lowering drugs can be classed as first- or second-line treatments. At present, examples of first-line drugs are cholestyramine, nicotinic acid and gemfibrozil, while second-line drugs are lovastatin, simvastatin, probucol and 'third generation' fibrates. With increasing experience with the newer drugs regarding clinical efficacy and long term safety, one hopes that lovastatin, simvastatin and probucol will fulfil all criteria and become first-line drugs. These have advantages over cholestyramine and nicotinic acid in terms of better patient compliance.

Cholesterol↗

PubMed1999

Pharmacoeconomic consequences of variable patient compliance with prescribed drug regimens.

Variable compliance with prescribed drug regimens is a leading source of variability in drug response. Specifics differ by drug and disease. The role of variable compliance was clearly defined in 2 trials of lipid-lowering agents, cholestyramine and gemfibrozil, in which exceptionally careful measurements of compliance were made, which has not been done in later trials. Economic consequences of variable compliance are estimated by converting dose-dependent changes in absolute risk of incident coronary disease into the unicohort format, which designates how many patients must be treated to prevent, in a given time, a defined 'coronary event'. Two strong influences on the costs of treatment are: (i) the shape of the relation between drug intake and risk reduction; and (ii) the strength of the linkage between intake and prescription refills. The intake-effect relation for cholestyramine is linear, making compliance-neutral the cost to prevent 1 coronary event, provided that refills match intake. If refills exceed intake, treatment costs rise. The intake-effect relation for gemfibrozil is more typically nonlinear, so poorer compliers purchase and take the drug in amounts that have little benefit, increasing the cost to prevent 1 coronary event. If refills run at a higher rate than intake, costs increase still further. A key question for future study is: do policies that encourage timely refills increase compliance enough to offset their potential to waste money in the purchasing of an untaken drug?

Cost of Illness↗

PubMed2006

Cost effectiveness of adding ezetimibe to atorvastatin therapy in patients not at cholesterol treatment goal in Canada.

INTRODUCTION: This analysis compared the cost effectiveness of adding ezetimibe to atorvastatin therapy versus atorvastatin titration or adding cholestyramine (a resin) for patients at high risk of a coronary artery disease (CAD) event who did not reach target cholesterol levels on their current atorvastatin dosage. The primary analysis focused on 65-year-old patients with low-density lipoprotein cholesterol (LDL-C) levels of 3.1 or 3.6 mmol/L with a treatment goal of <2.5 mmol/L, classified as very high risk according to the 2000 Canadian Guidelines for Management and Treatment of Hyperlipidaemia. METHODS: A previously developed Markov model was utilised to capture the cost and clinical consequences of lipid-lowering therapy in primary and secondary prevention of CAD. Comparisons between treatment strategies were made using ICERs (cost per QALY) from a Canadian Ministry of Health perspective. The effects of lipid-lowering therapies were based on clinical trial data. The risks of CAD events were estimated using Framingham Heart Study risk equations. Treatment costs and the costs of acute and long-term care for CAD events were included in the analysis. Costs (Canadian dollar, 2002 values) and outcomes were discounted at 5% per annum. RESULTS: Ezetimibe added to atorvastatin therapy compared with treatment with the most common fixed atorvastatin daily dosage (10 mg) or with common atorvastatin titration strategies (up to 20 mg daily; up to 40 mg daily) resulted in cost per QALY estimates ranging from 25,344 to 44,332 Canadian dollars. The addition of ezetimibe to atorvastatin therapy was less costly and more effective than the addition of cholestyramine (dominant). CONCLUSION: Our analysis suggests that adding ezetimibe to atorvastatin for patients not achieving treatment goals with their current atorvastatin dose produces greater clinical benefits than treatment with a fixed-dose atorvastatin or atorvastatin titration at an increased overall cost. The cost-effectiveness ratios provide strong evidence for the adoption of ezetimibe within the Canadian healthcare system.

Adult↗

PubMed1984

The changes in plasma lipoproteins in a case of heterozygous familial hypercholesterolemia after plasmapheresis.

The changes in plasma lipoproteins after plasmapheresis were estimated in a case of heterozygous familial hypercholesterolemia. Two and a half liters of plasma were exchanged with the same volume of Plasmanate. The effects of cholestyramine on the changes in plasma lipoproteins were also studied after the second plasmapheresis. Fasting plasma was collected serially, and plasma VLDL, IDL, LDL1 (1.019 less than d less than 1.045), LDL2 (1.045 less than d less than 1.063), HDL2 (1.063 less than d less than 1.125) and HDL3 (d greater than 1.125) were separated by ultracentrifugation. The cholesterol and apoprotein contents in these lipoprotein fractions were analyzed. Apoprotein AI, AII, B, CII and E were measured by single radial immunodiffusion. VLDL-C and plasma apoprotein CII and E increased very rapidly. The IDL-C increase was slightly slower than that of VLDL-C. LDL1-C continued to increase for three weeks, but LDL2-C reached a plateau around a week after plasmapheresis and declined thereafter. The change of apoprotein B was similar to that of cholesterol in VLDL, IDL, LDL1 and LDL2. Cholesterol amounts in HDL2 and HDL3 changed in a parallel manner, as did apoprotein AI and AII. HDL2 and HDL3 reached their preplasmapheresis levels in a week. Cholestyramine did not inhibit the increase of VLDL, IDL, LDL1 or LDL2 in this case.

Adult↗

PubMed2000

Carboxypeptidase G2 rescue in delayed methotrexate elimination in renal failure.

We report here the case of a 68-year-old woman who presented severe renal failure following the first cycle of high dose methotrexate (HDMTX) for the treatment of a cerebral malignant lymphoma. Before HDMTX administration, serum creatinine value was normal and three days after HDMTX, it reached 457 micromol/L. Leucovorin rescue, hemodialysis and cholestyramine did not increase MTX clearance. Because of the persistence of renal failure, and the high risk of important hematological side-effects associated with high MTX plasma levels, the patient received carboxypeptidase G2 (CPDG2). This allowed MTX plasma levels to decrease by 80% in 15 minutes. No side effects were observed and renal function normalized rapidly. In some patients, when high-dose leucovorin associated with hemodialysis and cholestyramine are unable to restore normal MTX clearance, CPDG2 should be considered because it may represent a safe and efficient alternative for the management of MTX intoxication.

Aged↗

PubMed1997

Microvillus inclusion disease in two Korean infants.

We report two cases of microvillus inclusion disease and these are the first cases in Korea. The two babies (one baby had a sibling who died of diarrhea in the neonatal period) had excreted their stools up to 200 ml/kg per day since several days after birth. Workup's included extensive infectious, immunologic, hormonal and rheumatologic studies, all of which were negative or normal. Diagnosis rested on the ultrastructural finding of intracytoplasmic inclusions that contained intact microvilli on electron microscopy. We tried somatostatin analogue (octreotide, 4 micrograms/kg/day), cholestyramine (up to 4g t.i.d.), steroid (prednisone, 2 mg/kg/day) and intravenous epidermal growth factor (100 ng/kg/hr for 2 weeks), but there was mild improvement with cholestyramine (decrease stool volume) and epidermal growth factor (increase the number of microvilli per cell) but no improvement was noted with the other treatments. Although it is a rare disorder and the prognosis of microvillus inclusion disease is poor, it must be considered if an infant has chronic secretory diarrhea.

Diarrhea, Infantile↗

PubMed2000

Sorption of fluoroacetate (compound 1080) by Colestipol, activated charcoal and anion-exchange in resins in vitro and gastrointestinal decontamination in rats.

The sorption of sodium fluoroacetate (FA) by activated charcoal (AC) and 5 anion exchange resins (AERs) was tested in 2 simulated gastrointestinal (GI) fluids. Each sorbent was incubated with FA in a shaker-water-bath at 37 C for 24 h. Supernatant was removed and filtered, and the concentration of FA was determined by gas chromatographic detection of the dichloroaniline derivative. Under simulated gastric conditions (0.1 M HCl at approximately pH 1.5), the sorbents removed the following proportions of FA from solution: Carbosorb AC, 87 +/- 2%; cholestyramine, 28 +/- 7%; colestipol, 96 +/- 0%; Amberlite IRA-96, 70 +/- 2%; DEAE-Sephadex, 7 +/- 4%; Chitosan, 66 +/- 2%. Under simulated intestinal conditions (0.05 M sodium phosphate at approximately pH 7.4), binding was as follows: Carbosorb AC, 68 +/- 4%; cholestyramine, 53 +/- 5%; colestipol, 46 +/- 2%; AmberliteIRA-96, 10 +/- 20%; DEAE-Sephadex, 64 +/- 7%; Chitosan, 5 +/- 2%. All findings differed significantly from control, with the exception of Amberlite IRA-96 and Chitosan in phosphate buffer, and DEAE-Sephadex in HCI. In a second study, rats were given 5 mg FA/kg, and then gavaged with 2 g/kg Carbosorb AC, colestipol or bentonite. Over 4 h, the area under the curve of serum FA versus time (AUC) decreased by 39% in the rats treated with colestipol and 42% in those treated with bentonite. In contrast, Carbosorb AC did not affect the AUC,yet increased Tmax In another study, mortality was assessed 96 h after rats were orally dosed with 5 mg FA/kg followed by gavage with 2 g/kg Carbosorb AC, colestipol or water immediatey or 30 min after dosing. When the sorbents were given immediately, mortality was the same as control (75%). Surprisingiy, the 30-min delay resulted in lower mortality in colestipol-treated rats, (approximately 38%) compared to 100% in the group treated with Carbosorb AC. Before any recommendation can be made regarding the use of colestipol as a GI decontaminant, the latter findings require confirmation in an intensive care setting. The potential for synergistic effects with 2 or more sorbents also warrant investigating.

Adsorption↗

PubMedDate not supplied

[Small bowel overgrowth: a frequent complication after abdominal surgery in newborns].

BACKGROUND/PURPOSE: Surgery for congenital or acquired gastroenterological disorders, and particularly that associated with short bowel, is not infrequently complicated by Small Bowel Bacterial Over growth (SBBO). Aim of this study is to evaluate the clinical course of children undergoing bowel surgery in the newborn period, assessing the development of SBBO and the response to intensive treatment with a "bowel cocktail" of gentamycin, metronidazole and cholestyramine. METHODS: 17 children with various conditions were studied clinically and by Breath Hydrogen Test (fasting and after glucose). 14 children underwent more than one procedure. All children were treated with overall "bowel cocktail" of gentamycin, metronidazole and cholestyramine. RESULTS: 5 children recovered after one course of treatment and 11 children relapsed at least once and required further courses of therapy. One child died from TPN related liver failure and another following a liver and small bowel transplant for short bowel syndrome. A third child required total intestinal tube splinting according to Sauer and another one required a tapering of the preatretic enlarged jejunal loop. CONCLUSIONS: Our study suggests that children undergoing bowel surgery in the neonatal period and those having more than one procedure are at greater risk of developing small bowel bacterial overgrowth postoperatively. Interestingly, loss of the ileocecal valve was not associated with an increased risk of bacterial overgrowth.

Child↗

PubMed2000

DMP-504 (DuPont Pharmaceuticals Co).

DMP-504 is a novel hydrogel bile acid sequestrant being developed by DuPont for the potential treatment of primary moderate hypercholesterolemia. It is in phase III trials. Equilibrium binding studies coupled with computer simulation of human bile flow predict that DMP-504 could be 3- to 4-fold more potent than cholestyramine in a clinical setting. Preclinical pharmacology studies demonstrate DMP-504 is 6-fold more potent than cholestyramine at decreasing serum cholesterol in hamsters. Clinical studies, at doses ranging from 0.9 to 7.2 g/day, indicate that DMP-504 is well tolerated and decreases LDL-cholesterol by up to 34%. As of June 1997, DuPont was seeking to outlicense DMP-504, which will be marketed in an easy-to-swallow, non-gritty tablet.

Journal Article↗

PubMed2006

Nicotinic acid: new/old drug. Immediate or sustained release: too risky for a drug with no proven benefit.

(1) For patients with hypercholesterolaemia requiring primary or secondary prevention, pravastatin, simvastatin and atorvastatin have a proven benefit in terms of mortality and/or morbidity. Gemfibrozil and cholestyramine have a proven impact on morbidity. (2) The lipid-lowering properties of immediate-release nicotinic acid have been known for about 50 years, as have its frequent and sometimes severe adverse effects. About 70% of patients experience cutaneous flushing, and 20-30% develop gastrointestinal adverse effects. Hepatotoxic effects occur in about 2% of patients, especially in those using high daily doses or sustained-release formulations. (3) The clinical evaluation of immediate-release nicotinic acid is mainly based on two comparative placebo-controlled trials. One, involving 5000 patients monitored on average for 15 years, showed no effect on survival. One trial suggested that immediate-release nicotinic acid reduced the risk of recurrent myocardial infarction. (4) Sustained-release nicotinic acid has not been evaluated in terms of its effect on morbidity or mortality. It has been shown to lower LDL cholesterol and triglyceride levels and to raise the HDL cholesterol level. (5) This new pharmaceutical formulation has a profile and frequency of known adverse effects similar to those of immediate-release nicotinic acid. (6) When hypercholesterolaemia persists despite an appropriate diet, it is best to use one drug with a proven preventive impact on mortality and/or morbidity. This is not the case for sustained-release nicotinic acid. (7) When statin therapy is inadequate, it remains to be shown whether adding another cholesterol-lowering drug is beneficial in terms of morbidity and mortality. If, in rare cases, combination with a statin is envisaged, it is best to use gemfibrozil or cholestyramine. Note that gemfibrozil should only be combined with a statin with the greatest caution.

Anticholesteremic Agents↗

PubMed1990

Platelet reactivity and arachidonic acid metabolism in type II hyperlipoproteinaemia and its modification by cholesterol-lowering agents.

A significant percentage of patients suffering from a selective increase in plasma LDL cholesterol (type IIa hyperlipoproteinaemia) exhibits increased platelet reactivity. This includes enhanced platelet responsiveness against a variety of platelet-stimulating agents ex vivo and enhanced arachidonic acid metabolism associated with increased generation of arachidonic acid metabolites (thromboxane A2, 12-HETE) and secretion of platelet-storage products. It is possible, but not proven, that an elevated cholesterol content in the platelet membranes forms a common denominator for these responses. Agents that lower total plasma or LDL cholesterol in hypercholesterolaemic patients by interfering with cholesterol reabsorption from the gut (cholestyramine, cholestipol) or reduction of hepatic VLDL release (fibrates) do not appear to interfere with platelet hyperreactivity and do not change platelet-derived thromboxane formation. There is also no correlation with the action of these agents on total plasma and LDL cholesterol. A different situation might exist with inhibitors of the HMG-CoA reductase, which have been found to reduce platelet hyperreactivity and thromboxane formation. However, this finding requires further confirmation in controlled, prospective, large trials. There is increasing evidence that patients with type II hyperlipoproteinaemia have a significant (by about 50%) reduced number of specific prostacyclin binding sites at the platelet membrane that might be involved in the reduced inhibition of platelet function by prostacyclin. Normalization of the reduced responsiveness against prostacyclin has also been demonstrated for cholestyramine and simvastatin. However, so far this issue has not been addressed for the other lipid-lowering compounds.

Anticholesteremic Agents↗

PubMed1990

[Guidelines for the treatment of hypercholesterolemia].

The prevalence of mild and moderate hypercholesterolemia among the middle-aged population of the G.D.R. is about 30%. Thus, this is the most important risk factor for coronary heart diseases. Primary therapeutic techniques are elimination of overweight, low-fat diet, rich in monoenic and polyenic acids, and increase of physical activity. When by these measures a decrease of cholesterol to 5.2-5.5 mmol/l is not achieved the introduction of lipid drugs is to be considered in dependence on the individual risk (associated risk factors like smoking, hypertension, diabetes, low HDL-cholesterol). In case of mild to moderate polygenic hypercholesterolemia cholestyramine, nicotinic acid and modern fibrates have the priority. Familial hypercholesterolemia demands as a rule the introduction of statins (e.g. lovastatin) or combinations of the above mentioned lipid drugs or the combination of cholestyramine and lovastatin, resp. In this way the prognosis even of patients with severe familial hypercholesterolemia can be improved decisively. Considering the fact that this would be a life-accompanying therapy a thorough consideration of the risk/benefit ratio and an adequate medical supervision are necessary.

Cholesterol, Dietary↗

PubMed1990

[Changes in lipoproteins and hormones induced by diet and drugs in patients with polygenic hypercholesterolemia. Predictive value of the determination of low density lipoprotein receptor activity].

To assess its hypolipidemic predictive value, maximally induced low density lipoprotein receptor activity was measured in vitro in peripheral blood lymphocytes from 20 polygenic hypercholesterolemic patients prior to their recruitment into a rigorous dietary and pharmacological treatment program. The subjects in the diet program demonstrated significant beneficial changes in plasma, LDL and HDL cholesterol concentrations. After 12 weeks, those patients who had not had reductions in LDL cholesterol to within the reference range had cholestyramine and/or bezafibrate supplements to the diet for a further 6 weeks. The beneficial trends continue. The initial LDL receptor values correlated well with pre-treatment LDL cholesterol and plasma cholesterol and apoprotein B concentrations, and with the percentage change induced by diet and by diet supplemented with bezafibrate and cholestyramine. During the trial the only significant variations in plasmatic hormones were observed in TSH and T3 concentrations, but always within the reference range. In polygenic hypercholesterolemic patients in whom LDL receptor activity is high, treatment with diet alone may be sufficient whereas those with low receptor activity would require specific pharmacological intervention.

Adult↗

PubMed1990

Aneurysm formation in experimental atherosclerosis: relationship to plaque evolution.

To determine whether aneurysms form in experimental diet-induced atherosclerosis, we reviewed our experience with cynomolgus monkeys (n = 268) and rhesus monkeys (n = 175) fed an atherogenic diet for various lengths of time. Many animals in long-term experiments were fed "regression" diets and cholestyramine to lower cholesterol levels after lesions were established. No aneurysms were found in animals on normal diet. There were no aneurysms in 252 animals fed an atherogenic diet with or without regression for 12 months or less. However, aneurysms formed in 13% of cynomolgus monkeys (4 of 31) and 1% (1 of 107) rhesus monkeys on an atherogenic regimen for 16 to 24 months. Four of the five animals with aneurysms were on a regression diet and cholestyramine for 4 to 12 months. The fifth was fed the atherogenic diet for 20 months without subsequent regression. Aneurysms were prominent and involved the thoracic and abdominal aorta, innominate artery, carotid arteries, iliac and femoral arteries, and formed in areas most involved with plaque formation in both species. Histologic evidence was found of thinning of the media and atrophy with loss of normal architecture. The higher incidence of aneurysms in cynomolgus monkeys was associated with greater media destruction than was noted in the rhesus. These data support the thesis that aneurysm formation is a manifestation of atherosclerosis. In primate atherosclerosis, aneurysms form only after prolonged exposure to the atherogenic regimen, even in the presence of declining serum cholesterol levels. Matrix fibers in plaques may provide structural support to the aortic wall where there is underlying atrophy of the media. With time or declining serum cholesterol levels or both, plaques may atrophy leaving an aortic wall too thin to support increasing mural tension, leading to aneurysmal enlargement.

Animals↗