Effects of pravastatin and ursodeoxycholic acid on cholesterol and bile acid metabolism in patients with cholesterol gallstones

Grading operative findings at laparoscopic cholecystectomy- a new scoring system

INTRODUCTION

Variation in outcomes from surgery is a major challenge and defining surgical findings may help set benchmarks, which currently do not exist in laparoscopic cholecystectomy. This study outlines a new surgical scoring system incorporating key operative findings.

METHODS

English language studies (from January 1965 to July 2014) pertaining to severity scoring and predictors of difficult laparoscopic cholecystectomy were searched for in PubMed, Embase and Cochrane databases using the search terms 'Laparoscopic cholecystectomy or Lap chole' and/or 'Scoring Index or Grading system or Prediction of difficulty or Conversion to open' in various combinations. Cross-referencing from papers retrieved in the original search identified additional articles.

RESULTS

Sixteen published papers report a gallbladder (GB) scoring system, but all relate to pre-operative clinical and imaging findings, rather than operative findings. The current scoring system, using operative findings incorporates the appearance of the GB, presence of GB distension, ease of access, potential biliary complications and time taken to identify cystic duct and artery. A score of <2 would imply mild difficulty, 2-4 moderate, 5-7 severe and 8-10 extreme.

CONCLUSION

This paper reports one of the first operative classifications of findings at laparoscopic cholecystectomy. It has the potential to allow benchmarks for international collaboration of operative and patient outcomes in patients undergoing laparoscopic cholecystectomy.

Atorvastatin induces bile acid-synthetic enzyme Cyp7a1 by suppressing FXR signaling in both liver and intestine in mice

Statins are effective cholesterol-lowering drugs to treat CVDs. Bile acids (BAs), the end products of cholesterol metabolism in the liver, are important nutrient and energy regulators. The present study aims to investigate how statins affect BA homeostasis in the enterohepatic circulation. Male C57BL/6 mice were treated with atorvastatin (100 mg/kg/day po) for 1 week, followed by BA profiling by ultra-performance LC-MS/MS. Atorvastatin decreased BA pool size, mainly due to less BA in the intestine. Surprisingly, atorvastatin did not alter total BAs in the serum or liver. Atorvastatin increased the ratio of 12α-OH/non12α-OH BAs. Atorvastatin increased the mRNAs of the BA-synthetic enzymes cholesterol 7α-hydroxylase (Cyp7a1) (over 10-fold) and cytochrome P450 27a1, the BA uptake transporters Na⁺/taurocholate cotransporting polypeptide and organic anion transporting polypeptide 1b2, and the efflux transporter multidrug resistance-associated protein 2 in the liver. Noticeably, atorvastatin suppressed the expression of BA nuclear receptor farnesoid X receptor (FXR) target genes, namely small heterodimer partner (liver) and fibroblast growth factor 15 (ileum). Furthermore, atorvastatin increased the mRNAs of the organic cation uptake transporter 1 and cholesterol efflux transporters Abcg5 and Abcg8 in the liver. The increased expression of BA-synthetic enzymes and BA transporters appear to be a compensatory response to maintain BA homeostasis after atorvastatin treatment. The Cyp7a1 induction by atorvastatin appears to be due to suppressed FXR signaling in both the liver and intestine.

[Effect of ursodeoxycholic acid combined with statins in hypercholesterolemia treatment: a prospective clinical trial]

INTRODUCTION

A possible synergistic effect of the combination treatment with statins and ursodeoxycholic acid (UDCA) for reduction of total cholesterol and LDL cholesterol plasma levels has been suggested.

PATIENTS AND METHODS

Random prospective clinical trial in 48 patients with primary or family hypercholesterolemia nonrespondent to simvastatin or atorvastatin treatment. The patients were assigned to a double statin dose group or to a group of combined treatment with simvastatin or atorvastatin and ursodeoxycholic acid for 4 months. Total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides plasma levels were evaluated.

RESULTS

The administration of simvastatin 20 mg/day + UDCA 300 mg/day yielded significantly greater reduction of LDL cholesterol plasma levels compared with the group of patients treated with simvastatin 40 mg/day (118.8 +/- 8.6 vs 154.8 +/- 12.2, respectively; p = 0.0034). Moreover, addition of atorvastatin 20 mg/day to UDCA 300 mg/day was more effective that atorvastatin 40 mg/day in single-dose for LDL cholesterol reduction after 4 months of treatment (94.6 +/- 6.1 versus 138.7 +/- 9.0, respectively; p = 0.0037). No significant adverse effects were observed in any of the analyzed groups.

CONCLUSIONS

Our results suggest the effectiveness of combination therapy with statins at low doses and UDCA in the treatment of patients with primary or family hypercholesterolemia initially nonrespondent to low doses of simvastatin or atorvastatin.

The sedimentable sterols in gallstone patients before and during ursodeoxycholic acid and simvastatin treatments

BACKGROUND

The insoluble material in supersaturated bile is prerequisite for the formation of gallstones. We therefore studied the biliary precipitable and soluble cholesterol and noncholesterol sterols, including the cholesterol precursor sterols (including lanosterol and lathosterols), and the plant sterols campesterol and sitosterol, and cholestanol, which usually reflect cholesterol synthesis and absorption, respectively, before and after a 6-month treatment with ursodeoxycholic acid (UCDA), 15.4 +/- 4 mg/kg/day (standard error of the mean) or simvastatin (40 mg/day) in 21 patients with cholesterol gallstones, to obtain further information about the factors contributing to the formation of gallstones.

METHODS

The sediment and supernatant fractions of duodenal bile samples were separated by ultracentrifugation and analyzed with gas-liquid chromatography.

RESULTS

At the base line (n = 21) 50% +/- 3% of biliary cholesterol and a variable amount of the noncholesterol sterols (from 14% of lanosterol to 62% of cholestanol) were in the sediment fraction. The pattern of the noncholesterol sterols in the sediment resembled that of gallstones described previously. At base line body mass index was positively related to the percentage of precipitable cholesterol in bile (r = 0.46, P < 0.05), and the serum sitosterol proportion negatively related to the molar percentage of biliary cholesterol and positively to that of bile acids (r = -0.46 and r = 0.50, P < 0.05 for both). UDCA decreased the precipitable percentage of cholesterol from 46% to 31% (P < 0.03) and simvastatin from 57% to 42% (P = 0.05). Both drugs also decreased the precipitable percentages of lathosterols and cholestanol while increasing that of lanosterol. In relation to cholesterol, the sediment to supernatant ratios of all methylsterols were increased, whereas those of polar lathosterols tended to decrease during UDCA treatment.

CONCLUSIONS

Patients with high body mass index have more precipitable cholesterol in their bile. Although both UDCA and simvastatin decreased the precipitable cholesterol, the bile still contained one-third of its cholesterol in the sedimentable form.

Short-term effects of 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor on cholesterol and bile acid synthesis in humans

Competitive inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase improve hypercholesterolemia. However, reports about the effects of these agents on bile acid synthesis, the metabolic pathway of cholesterol, are conflicting. We studied the short-term effect on one of these agents, pravastatin, on bile acid synthesis. Six male volunteers were given 40 mg of pravastatin. Plasma mevalonate level (which reflects cholesterol synthesis) and 7 alpha-hydroxy-4-cholesten-3-one level (which reflects bile acid synthesis) were measured every 2 h for 8 h. These plasma levels were compared to those of the same volunteers without pravastatin. Plasma mevalonate level after 2 h was lower than control (3.0 +/- 1.1 ng/mL vs. 6.7 +/- 2.5, mean +/- SD; P < 0.05). This decrease continued for 8 h (2.5 +/- 0.8 vs. 5.2 +/- 1.5; P < 0.05). On the other hand, plasma 7 alpha-hydroxy-4-cholesten-3-one level did not change until after 6 h; then at 8 h it was lower than control (15.7 +/- 11.8 ng/mL vs. 24.7 +/- 16.9; P < 0.05). According to three-way layout analysis of variance, mevalonate level was influenced by both pravastatin treatment (P < 0.01) and time-course (P < 0.01). On the other hand, the 7 alpha-hydroxy-4-cholesten-3-one level was affected by both individual difference (P < 0.01) and time course (P < 0.01), but pravastatin treatment did not influence this compound. This indicates that bile acid synthesis was influenced by pravastatin, although cholesterol synthesis was inhibited. The short-term inhibition of cholesterol synthesis did not affect bile acid synthesis.

Clinical pharmacokinetics of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is the key enzyme of cholesterol synthesis. HMG-CoA reductase inhibitors are potent reversible inhibitors of this enzyme, which act by competing for the substrate HMG-CoA. This review is mainly devoted to the 4 main HMG-CoA reductase inhibitors used today: lovastatin, simvastatin, pravastatin and fluvastatin. Depending upon the dosage, these drugs are able to reduce plasma cholesterol levels by more than 40%. After absorption, each undergoes extensive hepatic first-pass metabolism. Up to 5 primary metabolites are formed, some of which are active inhibitors. The elimination half-lives vary from 0.5 to 3.5 hours and excretion is mainly via the faeces. A limited number of drug interactions has been reported. Increases in liver enzymes and muscle creatine kinase activity are among the most severe adverse effects. These powerful drugs should be reserved for patients with high plasma cholesterol levels and/or those with cardiovascular disease. New therapeutic approaches to atherosclerosis are currently under investigation. HMG-CoA reductase inhibitors are the cornerstone of this research.

Effects of long-term treatment with low-dose pravastatin on biliary lipid and bile acid composition in patients with nonfamilial hyperlipoproteinemia

We tested the possibility that pravastatin, a competitive inhibitor of hepatic hydroxymethyl glutaryl coenzyme A (HMG CoA) reductase, would alter cholesterol saturation of gallbladder bile by decreasing its cholesterol saturation index and/or degree of fatty acyl chain unsaturation in lecithin. Eighteen patients with type IIa hyperlipoproteinemia were treated with pravastatin 10 mg/d for 12 months. Gallbladder bile samples were aspirated with a duodenal tube by stimulating gallbladder contraction with intramuscular administration of cerulein before and after treatment. Serum cholesterol level was significantly reduced by 20% after 3 months, and this level was maintained after 12 months. In contrast, the cholesterol saturation index of gallbladder bile was not altered after 3 months (1.52 +/- 0.20 v 1.70 +/- 0.24), but it decreased significantly after 12 months (0.95 +/- 0.11, P < .01). The degree of fatty acyl chain unsaturation tended to decrease, although this was not statistically significant except for the decrease in molar percent of linoleate after 3 months. These findings suggest that long-term treatment with an inhibitor of HMG CoA reductase improves bile lithogenicity even at a comparatively low dose, and can decrease the incidence and complications of cholesterol gallstones.