The effect of ethynyl oestradiol on biliary lipid composition in young men

Cholesterol cholelithiasis in pregnant women: pathogenesis, prevention and treatment

Epidemiological and clinical studies have found that gallstone prevalence is twice as high in women as in men at all ages in every population studied. Hormonal changes occurring during pregnancy put women at higher risk. The incidence rates of biliary sludge (a precursor to gallstones) and gallstones are up to 30 and 12%, respectively, during pregnancy and postpartum, and 1-3% of pregnant women undergo cholecystectomy due to clinical symptoms or complications within the first year postpartum. Increased estrogen levels during pregnancy induce significant metabolic changes in the hepatobiliary system, including the formation of cholesterol-supersaturated bile and sluggish gallbladder motility, two factors enhancing cholelithogenesis. The therapeutic approaches are conservative during pregnancy because of the controversial frequency of biliary disorders. In the majority of pregnant women, biliary sludge and gallstones tend to dissolve spontaneously after parturition. In some situations, however, the conditions persist and require costly therapeutic interventions. When necessary, invasive procedures such as laparoscopic cholecystectomy are relatively well tolerated, preferably during the second trimester of pregnancy or postpartum. Although laparoscopic operation is recommended for its safety, the use of drugs such as ursodeoxycholic acid (UDCA) and the novel lipid-lowering compound, ezetimibe would also be considered. In this paper, we systematically review the incidence and natural history of pregnancy-related biliary sludge and gallstone formation and carefully discuss the molecular mechanisms underlying the lithogenic effect of estrogen on gallstone formation during pregnancy. We also summarize recent progress in the necessary strategies recommended for the prevention and the treatment of gallstones in pregnant women.

Is there a link between oestrogen therapy and gallbladder disease?

Cholelithiasis is the most common form of benign gallbladder disease that results in major heath expenditure. Female sex hormones are causally related to cholesterol gallstone disease, which are more common in women than in men. The risk of development of cholelithiasis is further enhanced by the use of exogenous female sex hormones and by pregnancy. Oestrogens are used in oral contraceptives and in hormone replacement therapy (HRT). Oral contraceptives do not pose a greater risk for gallbladder disease. The findings from two randomised, controlled trials, the Heart and Oestrogen/Progestin Replacement Study and the Women's Health Initiative postmenopausal hormone trial, unequivocally confirm that oral oestrogen use in postmenopausal women is causally associated with gallbladder disease, and the magnitude of the effect is not influenced greatly by the presence or absence of progestins. A cautious approach should be observed when prescribing HRT. Women must be informed about the effect of oestrogen use on increased risk of benign gallbladder disease. HRT should be used in the lowest possible dose for the shortest possible time. Women harbouring asymptomatic gallstones should not receive oestrogens because of the possibility of developing cholecystitis.

Drug-induced gallbladder disease. Incidence, aetiology and management

A great variety of drugs is reported to induce gallbladder disease by various pathogenetic mechanisms. Early epidemiological studies indicated a doubled risk of gallbladder disease in women taking oral contraceptives. More recent studies, however, have failed to confirm those findings; these conflicting results might be explained by the different methods used to define gallbladder disease. It was shown that the lithogenic index of the bile is increased during intake of oral contraceptives. Estrogens cause hypersecretion of cholesterol in bile, due to increase in lipoprotein uptake by the hepatocyte. Progesterone inhibits acyl coenzyme A-cholesterol acyl transferase (ACAT) activity, causing delayed conversion of cholesterol to cholesterol esters. Of the lipid lowering drugs, only clofibrate has been shown to increase the risk for gallstone formation. The other fibric acid derivatives have similar properties, but clinical experience is not as extensive. They seem to be inhibitors of the ACAT enzyme system, thereby rendering bile more lithogenic. Conflicting epidemiological data exist regarding the induction of acute cholecystitis by thiazide diuretics. Ceftriaxone, a third-generation cephalosporin, is reported to induce biliary sludge in 25 to 45% of patients, an effect which is reversible after discontinuing the drug. The sludge is occasionally a clinical problem. It was clearly demonstrated that this sludge is caused by precipitation of the calcium salt of ceftriaxone excreted in the bile. Long term use of octreotide is complicated by gallstone formation in approximately 50% of patients after 1 year of therapy, due to gallbladder stasis. Hepatic artery infusion chemotherapy by implanted pump is shown to be associated with a very high risk of chemically induced cholecystitis. Prophylactic cholecystectomy at the time of pump implantation is therefore advocated. Some drugs, such as erythromcyin or ampicillin, are reported to cause hypersensitivity-induced cholecystitis. Furthermore, there are reports on the influence of cyclosporin, dapsone, anticoagulant treatment, and narcotic and anticholinergic medication in causing gallbladder disease.

Different hepatobiliary effects of oral and transdermal estradiol in postmenopausal women

Estrogen-replacement therapy is important for the prevention of postmenopausal osteoporosis. However, oral synthetic and conjugated estrogens increase biliary cholesterol saturation index and risk of gallstone disease. To examine whether transdermal estrogen administration could avoid these adverse effects, 17 postmenopausal women were treated with transdermal estradiol (Estraderm TTS; Ciba-Geigy, Arnhem, The Netherlands), 100 micrograms/day for 4 weeks, and after 1 month without therapy, with oral estradiol (Progynova; Schering, Weesp, The Netherlands), 2 mg/day for 4 weeks. The increase in the serum estradiol level was much higher during transdermal than oral estradiol administration. On the contrary, the increase in the serum estrone level was much more pronounced during oral treatment. Both modes of treatment led to a similar reduction of urinary calcium excretion. A highly significant decrease in serum phosphate levels was found during transdermal therapy. Biliary cholesterol saturation index did not change during transdermal therapy (mean +/- SEM, 1.25 +/- 0.06 before and 1.22 +/- 0.07 at the end of transdermal therapy; P = NS). A slight increase in cholesterol saturation index that did not reach statistical significance was found during oral therapy (1.28 +/- 0.09 before and 1.36 +/- 0.09 during oral treatment). However, the subgroup of women with strong increases in serum estrone levels during oral estradiol therapy (greater than 0.5 pmol/mL; n = 8) generally had increased biliary cholesterol saturation index, a decrease in relative percentage chenodeoxycholic acid in bile, and increased serum sex hormone-binding globulin levels during oral treatment. Cholesterol monohydrate crystals were never found in duodenal biles during either treatment. This study indicates that transdermal estradiol does not induce lithogenic bile. On the contrary, oral estradiol leads to lithogenic bile in a subgroup of women with strong increases in serum estrone levels during oral treatment.

Mechanisms of gallstone formation in women. Effects of exogenous estrogen (Premarin) and dietary cholesterol on hepatic lipid metabolism

Our aim was to define mechanisms whereby conjugated estrogens (Premarin, exogenous estrogen; Ayerst Laboratories, New York) increase the risk of developing cholesterol gallstones and to determine the role, if any, of dietary cholesterol. We studied gallbladder motor function, biliary lipid composition and secretion, cholesterol absorption, cholesterol synthesis and esterification by peripheral blood mononuclear cells, the clearance of chylomicron remnants, and bile acid kinetics in 29 anovulatory women. 13 were studied on both a low (443 +/- 119 mumol/d) and high (2,021 +/- 262 mumol/d) cholesterol diet. Premarin increased the lithogenic index of bile (P less than 0.05), increased biliary cholesterol secretion (P less than 0.005), lowered chenodeoxycholate (CDCA) pool (P less than 0.001) and synthesis (P less than 0.05), altered biliary bile acid composition [( CA + DCA]/CDCA increases, P less than 0.005), stimulated cholesterol esterification (P less than 0.03), and enhanced the clearance of chylomicron remnants (P = 0.07). Increases in dietary cholesterol stimulated the biliary secretion of cholesterol (P = 0.07), bile acid (P less than 0.05), phospholipid (P = 0.07), and as a result, did not alter lithogenic index. The reduction in CDCA pool and synthesis by Premarin was reversed by increasing dietary cholesterol. Off Premarin, only 24% of the increase in cholesterol entering the body in the diet was recovered as biliary cholesterol or newly synthesized bile acid. On Premarin, 68% of this increase in cholesterol was recovered as these biliary lipids. We conclude that Premarin increases biliary cholesterol by enhancing hepatic lipoprotein uptake and inhibiting bile acid synthesis. These actions of Premarin divert dietary cholesterol into bile.

Estrogen-induced gallstone formation in males. Relation to changes in serum and biliary lipids during hormonal treatment of prostatic carcinoma

To assess if and by which mechanisms pharmacological estrogen treatment induces gallstone disease, we examined patients with recently diagnosed prostatic cancer randomly allocated to estrogen therapy (n = 37) or orchidectomy (n = 35). According to gallbladder ultrasonography, after 1 yr new gallstones had developed in 5 of 28 estrogen-treated patients, compared with 0 of 26 orchidectomized patients (P = 0.03). Estrogen therapy for 3 mo increased the relative concentration of cholesterol and cholesterol saturation of bile by approximately 30% (n = 10). Serum LDL cholesterol was reduced by approximately 40%, and its relative change related inversely to that of bile cholesterol (Rs = -0.77). There were no changes in biliary or serum lipids after orchidectomy (n = 9). Secretion rates of biliary lipids were measured with a duodenal perfusion technique. Patients on chronic estrogen therapy (n = 5) had approximately 40% higher biliary excretion rates of cholesterol than age-matched controls (n = 7). Phospholipid secretion was also higher, but no difference in bile acid secretion was found. We conclude that an increased hepatic secretion of cholesterol results in increased cholesterol saturation of bile and an enhanced rate of gallstone formation during estrogen treatment. The changes in bile cholesterol seem to be related to the induced changes in serum lipoprotein metabolism.

Ethinylestradiol stimulates a biliary cholesterol-phospholipid cosecretion mechanism in the hamster

The mechanism of ethinylestradiol-induced biliary secretion of excess cholesterol, a potential causative factor of cholesterol gallstones, is not yet known. It might be related to altered bile acid metabolism, since the rate of cholesterol and phospholipid secreted into bile is thought to be influenced by the hydrophobicity of the bile acid species secreted. We therefore studied the effect of ethinylestradiol on bile acid metabolism and on secretory relationships between taurocholate and cholesterol/phospholipids in bile. Litter-matched Syrian female hamsters (80 to 100 gm body weight) were injected subcutaneously with either 0.2 ml per day corn oil (controls) or a pharmacologic dose of 5 mg per kg per day ethinylestradiol in corn oil (EE-hamsters; n = 6) for 5 days. On Day 6, bile was collected for 60 min (basal secretory rate) via a bile duct fistula after exclusion of the gallbladder. Then, a graded infusion of taurocholate was given for 110 to 130 min. Secretory rates (nmoles.min-1.-1 liver) for bile acids, cholesterol and phospholipids were determined and their mutual "linkage coefficients" (nmoles of secretory increment per 1 nmole of bile acid secreted) calculated by linear regression analysis. EE-hamsters had higher (p less than 0.02) basal secretory rates of cholesterol (0.71 +/- 0.21 vs. 0.45 +/- 0.10) and phospholipids (5.74 +/- 1.04 vs. 4.21 +/- 0.73) than controls at comparable bile flow and bile salt secretion rates. Cholic acid pool size and the fractional composition of bile acid species in bile were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Gall stones in a Danish population: fertility period, pregnancies, and exogenous female sex hormones

From a cross sectional study of gall stone disease ascertained by ultrasonography, the prevalence in relation to age at menarche, use of oral contraceptives, childbirths, breastfeeding, abortions, age at menopause, and menopausal hormone therapy was assessed. The random sample comprised 2301 women of Danish origin aged 30, 40, 50, and 60 years, of whom 1765 (77%) attended the investigation. Gall stone disease was significantly associated with young age at menarche, abortions, and multiple childbirth. Use of oral contraceptives was significantly associated with gall stone disease in univariate analysis, but not in multivariate analysis. Breastfeeding, age at menopause and menopausal hormone therapy were not associated with gall stones. These determining variables seemed sufficient to explain the higher prevalence of gall stone disease in women than in men.

Increased risk of cholecystectomy in users of supplemental estrogen

We report the results of an analysis of information from a prospective cohort study of women examining the association between cholecystectomy and use of supplemental estrogens (never, current, and past use). There were 55 cases of cholecystectomy in those who had never used estrogen and 105 cases in those who had ever used estrogen. After adjustment for age, the relative risk of cholecystectomy in those who had ever used estrogen was 2.1 (95% confidence interval, 1.5-3.0). In women classified as current users based on information available in 1977, the relative risk of gallbladder disease was 2.7 (95% confidence interval, 1.8-4.0) and in past users as of this date, it was 1.6 (95% confidence interval, 1.1-2.5). When cases known to have reinitiated estrogen use after 1977 are removed from the numerator for past users and added to the numerator for current users, the relative estimate for past use decreased to 1.1 (95% confidence interval, 0.7-1.8), and the risk estimate for current use increased to 3.9 (95% confidence interval, 2.6-5.9). Although an increase in the risk of gallbladder disease in women using supplemental estrogens has been consistently observed in previous studies, the risk after cessation of use has received little attention but could be important. Our data suggest the possibility that the risk of gallbladder disease in estrogen users persists after use of the drug ceases. An increase in the risk of cholecystectomy in estrogen users that persists after drug use ends is plausible if estrogen-induced increases in the lithogenicity of bile cause gallstones to form during drug use and if these gallstones fail to dissolve even after bile lithogenicity returns to normal upon cessation of use. The effect of estrogen use on the gallbladder should be considered in weighing the net risk-benefit ratio of these drugs.

The effect of a progestin-only oral contraceptive on biliary lipid composition in the cat

Following a control period of 5 weeks, 3 female cats with chronic gastric and duodenal fistulae were given 37.5 micrograms of the progestin D-norgestrel for 15 weeks. The study was continued for 8 weeks after withdrawal of treatment. Bile was collected via the duodenal fistula at 7-10 day intervals. During treatment the combined molar percentage of biliary cholesterol of all cats (4.2 +/- 0.4, n = 34) was significantly lower than during the control period (8.2 +/- 1.3, n = 11) [P = 0.001], and remained depressed after treatment withdrawal (5.5 +/- 1.0, n = 11) [P = 0.02]. The molar percentage of phospholipids remained unchanged in all animals, and that of total bile acids increased during treatment in one animal. As assessed by triangular coordinate plotting, the bile of each animal became less saturated with cholesterol during norgestrel administration. These results support the concept that the oestrogen component may be a major factor in the development of increased biliary cholesterol saturation in users of mixed-type oral contraceptives.

The effect of drugs on bile flow and composition. An overview

Many drugs are eliminated via the hepatobiliary route, after biotransformation in the liver. Some of them may affect bile flow and/or the hepatic secretion of biliary lipids such as bile acids, cholesterol and phospholipids. Bile acids are the most potent agents which increase bile flow, especially unconjugated bile acids. Other drugs which increase bile flow include phenobarbitone (phenobarbital), theophylline, glucagon and insulin. In contrast, ethacrynic acid, amiloride, ouabain, oestrogens and chlorpromazine are among those agents which decrease bile flow. Biliary bile acid secretion is altered by a variety of drugs, including cheno- and ursodeoxycholic acids (CDCA and UCDA), the bile acid sequestrants cholestyramine and colestipol, and ethinyloestradiol. The composition of bile can also be altered by drug therapy. Thus, clofibrate increases biliary cholesterol secretion, and reduces bile acid concentrations, without altering biliary phospholipid concentrations. However, other clofibrate derivatives may produce changes of a different pattern, suggesting that the risk of developing gallstones may differ for each derivative. Nicotinic acid and d-thyroxine also increase biliary cholesterol saturation, while CDCA and UDCA reduce biliary cholesterol concentration. The potential consequences of drug-induced changes in bile flow and composition extend to the liver, the gallbladder and the intestine. If adverse effects are to be avoided, further study in this often overlooked area is required.

Effects of short-term treatment with a combined oestrogen-progestin oral contraceptive on biliary lipids and cholesterol saturation index in young women

The effect of daily ingestion for 7 days of ethinyloestradiol (30 micrograms) plus DL-norgestrel [0.5 mg] (Eugynon-30) on the lipid composition of duodenal bile in 8 healthy young women was investigated from the fifth day after onset of menstrual bleeding. This treatment did not significantly affect the concentrations of cholesterol, phospholipid and total bile acids expressed as mmol/l, nor the mean molar percentage of phospholipid. However, the treatment caused a significant increase in the mean molar percentage of cholesterol which was accompanied by a significant decrease in the mean molar percentage of total bile acids. The cholesterol saturation index of the bile of 7 subjects was elevated after treatment while both serum cholesterol and testosterone were significantly reduced. The results show that administration to healthy young women, not previously exposed to oral contraceptives, with a low oestrogen-progestin preparation for only 7 days produces a more lithogenic bile, accompanied by a decrease in serum cholesterol and plasma testosterone concentrations.

Effect of synthetic oestrogens and progestagens in oral contraceptives on bile lipid composition

The prevalence of cholesterol gall stones in young women has increased since the introduction of oral contraceptives. The synthetic female sex hormones used in these preparations, increase the degree of cholesterol saturation in bile. To determine whether oestrogens, progestagens, or both, are responsible for the change in biliary cholesterol saturation index, a prospective randomised, controlled study was performed. A significant increase in the cholesterol saturation index of bile was observed when either 30 micrograms ethinyloestradiol plus 150 micrograms norgestrel (p = 0.01) or 50 micrograms ethinyloestradiol plus 250 micrograms norgestrel (p less than 0.01) were ingested daily for two months. No change in the cholesterol saturation index was observed when 30 micrograms ethinyloestradiol alone, or 30 micrograms ethinyloestradiol plus 2.5 mg norethisterone were used. The mechanism for the increase in cholesterol saturation index did not appear to involve bile acid metabolism. These results indicate that the progestagen, norgestrel, and not as previously thought the oestrogen, ethinyloestradiol, is responsible for the increase in cholesterol saturation of bile which accompanies the use of oral contraceptives.

High-density lipoprotein cholesterol: methods and clinical significance

The known limitations and advantages of methods for determining serum high-density lipoprotein (HDL) cholesterol concentration are reviewed with special emphasis on the applicability of each method to clinical medicine. The evidence for and against the relevance of serum HDL cholesterol to the prediction of the likelihood of an individual man or woman developing clinically evident ischemic heart disease is discussed. The possibility that HDL subfractions may be more relevant to this issue is also discussed. Information about serum HDL cholesterol concentration in diseases other than ischemic heart disease is reviewed. The effect of diet, body-weight, exercise, cigarette-smoking, alcohol intake, and hyperlipoproteinemia and the effect of modification of these factors on serum HDL cholesterol levels is discussed. Finally, a practical approach to the patient with a low concentration of serum HDL cholesterol is suggested.