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Abstract

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Statin therapy may target both hypercholesterolemia and cholestasis in primary biliary cirrhosis (PBC). However, little is known about the efficacy and safety of statins in PBC. The aim of this single-center study was therefore to prospectively examine the effects of atorvastatin on serum markers of cholestasis, aminotransferases, and lipid and bile acid metabolism as well as inflammatory and immunological markers in patients with PBC. Fifteen patients with early-stage PBC and an incomplete biochemical response to ursodeoxycholic acid (UDCA) therapy (defined as alkaline phosphatase 1.5-fold above the upper limit of normal after 1 year) were treated with atorvastatin 10 mg/day, 20 mg/day, and 40 mg/day for 4 weeks, respectively. Serum levels of alkaline phosphatase increased during atorvastatin 20 mg and 40 mg (P < 0.05), whereas leucine aminopeptidase and γ-glutamyltransferase remained unchanged. No statistical differences in overall serum ALT, AST, bilirubin, and IgM levels were observed. However, atorvastatin was discontinued in 1 out of 15 patients because of ALT 2-fold above baseline, and 2 patients showed ALT elevations 3-fold above the upper limit of normal at the end of the atorvastatin treatment period. Serum total cholesterol and low-density lipoprotein cholesterol levels decreased by 35% and 49%, respectively (P < 0.001). Precursors of cholesterol biosynthesis (lanosterol, desmosterol, lathosterol) showed a similar pattern. No changes in serum bile acid levels and composition were observed during treatment. Conclusion: Atorvastatin does not improve cholestasis in PBC patients with an incomplete biochemical response to UDCA but effectively reduces serum cholesterol levels. (HEPATOLOGY 2007.)

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by immunomediated destructive cholangitis that ultimately leads to ductopenia, biliary fibrosis, and cirrhosis.1, 2 Ursodeoxycholic acid (UDCA) 12-15 mg/kg/day is currently considered the standard therapy for PBC.3, 4 However, 39% to 67% of patients may show an incomplete biochemical response to UDCA.5, 6 Whereas patients with a complete biochemical response have a normal survival compared with the general population,5 patients with an incomplete biochemical response to UDCA remain at increased risk for progression to cirrhosis.6 Therefore, additional therapeutic options for the treatment of PBC may be necessary.

PBC is associated with hypercholesterolemia in 75% to 95% of cases,7–9 but its relevance in the risk of cardiovascular diseases is still controversial.10–15 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, also known as statins, are well established in the management of dyslipidemia. Their potential to reduce the concentration of low-density lipoprotein cholesterol (LDL-C) results in decreased cardiovascular morbidity and mortality.16–20 Statins are generally well tolerated and are not associated with an increased risk of hepatotoxicity in patients with nonalcoholic fatty liver disease21–24 or chronic hepatitis C.25, 26 However, limited data on safety of statins in chronic cholestatic liver diseases have been reported in small numbers of patients.27–30

We have demonstrated previously in mice that atorvastatin stimulates the expression of genes involved in bile formation and thus ameliorates cholestasis as reflected by reduced serum bile acid levels in bile duct–ligated mice.31, 32 Additional beneficial effects of statins in cholestasis could result from a stimulation of bile acid metabolism, detoxification, and transport, which are predicted to counteract bile acid toxicity.33 Part of these statin effects could be explained by activation of nuclear receptors such as the pregnane X receptor/sterol X receptor and peroxisome proliferator–activated receptor-α,31, 34–36 because these nuclear receptors have been shown to regulate transport and metabolism of biliary constituents.33 Thus, statins may be considered nuclear receptor–targeted agents that are already available for the treatment of liver disease. Moreover, anti-inflammatory and immunomodulatory effects observed in other immunomediated disorders such as rheumatoid arthritis and multiple sclerosis could also be beneficial in PBC.37, 38 However, very little is known about the effects of statin therapy on cholestasis in PBC.27–30

The aim of this study was to prospectively examine the effects of atorvastatin on serum markers of cholestasis, aminotransferases, and lipid and bile acid metabolism as well as inflammatory and immune markers in PBC patients with an incomplete biochemical response to UDCA.

Patients and Methods

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Study Design.

This study was designed as prospective, single-center, single-blinded dose-finding study with a step-up dosage protocol of atorvastatin. A 4-week placebo run-in period was followed by an active treatment phase with atorvastatin 10 mg/day, 20 mg/day, and 40 mg/ day for 4 weeks, respectively, in addition to UDCA, which was continued during the entire study period. Finally, there was a follow-up visit 8 weeks after discontinuation of atorvastatin. The study was approved by the local ethics committee, and written informed consent was obtained from all participants before enrollment. Inclusion criteria were early-stage PBC (stage I-II on liver biopsy and/or positive antimitochondrial antibodies), an incomplete biochemical response to standard UDCA therapy6 (defined as an alkaline phosphatase (AP) level of at least 1.5-fold above the upper limit of normal (ULN) after 1 year of UDCA treatment; average dose 11.3 mg/kg/day) and optionally elevated total cholesterol (200-500 mg/dl). On average, liver biopsy was performed 9 years before study enrollment. Progression to clinically relevant cirrhosis at the time of study recruitment is extremely unlikely as suggested by normal spleen size on abdominal ultrasound, normal platelet count, prothrombin time, serum albumin, and low model for end-stage liver disease score (Table 1). Out of a total number of 123 UDCA-treated PBC patients at our Liver Outpatient Clinic, 60 patients (49%) had an incomplete biochemical response to UDCA (Fig. 1). Out of these, 18 patients were eligible for the study and gave informed consent to participate.

Table 1. Baseline Characteristics of Patients with PBC
CharacteristicValue
  1. NOTE. Values are expressed as the mean ± SD or as n (%).

  2. Abbreviations: BMI, body mass index; MELD, model for end-stage liver disease.

Females15 (100)
Age (years)56 ± 10
BMI (kg/m2)27.3 ± 6.4
Waist circumference (cm)86 ± 10
Alcohol (<40 g/w)7 (46.7)
No alcohol8 (53.3)
MELD score2 ± 2
Smoker (former and current)3 (20.0)
Diabetes mellitus2 (13.3)
Arterial hypertension4 (26.7)
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Figure 1. Enrollment of PBC patients. AP, alkaline phosphatase; PBC, primary biliary cirrhosis; UDCA, ursodeoxycholic acid.

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Exclusion criteria were PBC stage III-IV at the time of liver biopsy, age older than 75 years, decompensated liver disease (Child-Pugh class B/C, presence of ascites, esophageal varices), AST or ALT more than 3-fold above the ULN, creatine phosphokinase more than 5 times the ULN or 3 times the ULN with muscle pain, tenderness or weakness, severe renal dysfunction, nephrotic syndrome, known hypersensitivity to statins, pregnancy or breastfeeding, and premenopausal women without safe contraception.

Criteria for discontinuation included elevations of ALT or creatine phosphokinase more than 3-fold above the ULN, increase of ALT or AP 2-fold above baseline, creatine phosphokinase more than 5 times the ULN or 3 times the ULN with muscle pain, tenderness or weakness, and allergic reaction to study medication. Three patients did not continue the study before initiation of atorvastatin therapy, 2 for personal reasons and 1 because of gastrointestinal side effects of the placebo medication. In 1 patient, treatment had to be discontinued because of an ALT increase above 2-fold of baseline at atorvastatin 10 mg. Two patients at atorvastatin 40 mg showed an ALT elevation 3-fold above the ULN at the end of the atorvastatin treatment period. All patient data up to the date of discontinuation were included in an intention-to-treat analysis.

Patients were classified as smokers (former and current) or nonsmokers. Alcohol consumption in patients was classified as positive if they were not completely abstinent. In these cases, the patients only occasionally consumed alcohol and a dose greater than 40 g/week was never exceeded. Subjects were classified as diabetic if they were treated with insulin or oral antidiabetics. Arterial hypertension was considered present if the systolic blood pressure was ≥140 mm Hg and the diastolic blood pressure was ≥90 mm Hg or if the current medication included antihypertensive drugs.

Laboratory Analysis.

AP, ALT, AST, γ-glutamyltransferase, bilirubin, and creatine phosphokinase were measured using enzymatic reagents (Roche Diagnostics, Mannheim, Germany) and analyzed with a Modular (Roche Diagnostics). Leucine aminopeptidase was measured enzymatically (Randox, Crumlin, United Kingdom) on a Hitachi 917 from Roche. AP isoenzymes were determined by quantitative agarose gel electrophoresis (Helena BioSciences, Gateshead, United Kingdom).

IgM, IgG, and IgA were determined by immunonephelometry (Dade Behring, Marburg, Germany). “Sensitive” C-reactive protein was measured via immunonephelometry (Dade Behring, Marburg, Germany). Fibrinogen was measured according to Clauss (Dade Behring, Marburg, Germany). Antimitochondrial antibody titers were assessed using a standard immunofluorescence method on rat kidney slices; specificity was confirmed using ELISA with recombinant M2 antigen (Phadia, Freiburg, Germany).

Lipoproteins were separated using a combined ultracentrifugation/precipitation method (β-quantification).39 Cholesterol, triglycerides, and phospholipids were measured using enzymatic reagents (Wako Chemicals, Neuss, Germany). Apolipoprotein AI, apolipoprotein B and lipoprotein(a) were determined via immunoturbidimetry (Greiner, Flacht, Germany). Lipid and apolipoprotein analyses were performed on an Olympus AU640 (Olympus Diagnostika, Hamburg, Germany).

Mevalonic acid was determined in plasma via gas chromatography/mass spectrometry using d4-mevalonic acid lactone as an internal standard.40 Mevalonic acid was converted to the corresponding lactone, extracted into ethyl acetate, purified via silica gel chromatography, and eluted with dichloromethane:methanol (95:5 v/v). After derivatization with N-methyl-N-trimethylsilyltrifluoro-acetamide (containing 1% trimethylchlorosilane)/pyridine (2:1 v/v) at room temperature, samples were analyzed via electron ionization gas chromatography/mass spectrometry in single-ion–monitoring mode using ions at m/z 233 for the target and m/z 237 for the internal standard ion. The method was validated in a range from 0.5 to 128 ng mevalonic acid lactone/ml for plasma. The concentrations were calculated as mevalonic acid lactone and converted to mevalonic acid (factor 1.14), thus meeting all established validation acceptance criteria.

Cholesterol precursors (lanosterol, desmosterol, lathosterol), sterol metabolites (cholestanol, 7-hydroxysterol, 27-hydroxysterol) and phytosterols (campesterol, sitosterol, stigmasterol, brassicasterol) were determined after saponification (50% KOH), extraction (hexane), purification by silica gel chromatography and derivatization (N-methyl-N-trimethylsilyltrifluoro-acetamide containing 1% trimethylchlorosilane)/pyridine (2:1 v/v) at 25°C of plasma samples on gas chromatography/mass spectrometry using electron ionization and single-ion– monitoring of corresponding ions. Quantitation was performed using epicoprostanol as internal standard and correlation of peak area ratios in linear regression.

Bile acids (cholic acid, deoxycholic acid, chenodeoxycholic acid, lithocholic acid, ursodeoxycholic acid) were determined as unconjugated acids and as taurine and glycine conjugates using a tandem mass spectrometry method. The free acids and the corresponding conjugates were measured by 3 different MRM (multiple reaction monitoring) experiments within 1 high-performance liquid chromatography run, due to different ionization and fragmentation properties. High-performance liquid chromatography was performed on a reversed-phase (C18) column using a methanol/water gradient for chromatographic solution of isobaric bile acids. Quantitation was performed by the use of deuterated internal standards and correlation of peak area ratios in linear regression.

Statistical Analysis.

Continuous clinical and biological variables for PBC patients were analyzed by repeated-measures ANOVA. Nonparametric between-group comparisons were performed using the Friedman test. A value of P < 0.05 was considered statistically significant. The SPSS 14.0 statistical package (SPSS Inc, Chicago, IL) was used for all analyses.

Results

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

Baseline characteristics of patients with PBC are shown in Table 1. Seven patients had normal weight (body mass index <25 kg/m2), 6 patients were overweight (body mass index 25-30 kg/m2), and 1 patient was obese (body mass index 47 kg/m2). Body mass index and waist circumference did not change during therapy with lipid-lowering drugs.

Effects of Atorvastatin on Serum Liver Enzymes.

Serum levels of AP as indirect biochemical marker of cholestasis and primary efficacy parameter did not improve under statin therapy. Surprisingly, levels of AP even increased significantly during active treatment with atorvastatin 20 mg/day and 40 mg/day by 18% and 24%, respectively (Table 2). The average increase of AP by 11% at the starting dose atorvastatin 10 mg/day, however, did not reach statistical significance (Table 2). One and two out of fifteen patients had a pronounced (>50% of baseline) increase of AP at atorvastatin 10 mg/day and 40 mg/day, respectively. The individual changes of serum AP levels under 10 and 40 mg/day atorvastatin therapy are shown in Fig. 2A–B. AP levels returned to baseline at the follow-up visit after discontinuation of atorvastatin. Analysis of the AP isoenzymes revealed a preponderance of the liver fraction. Of note, no significant differences in serum levels of other biochemical markers of cholestasis such as γ-glutamyltransferase and leucine aminopeptidase were observed during statin therapy.

Table 2. Serum Liver Enzymes and Inflammatory Markers of Patients With PBC
 Baseline (Week 0)Atorvastatin 10 mg/day (Week 4)Atorvastatin 20 mg/day (Week 8)Atorvastatin 40 mg/day (Week 12)Follow-up (Week 20)
  • NOTE. Values are expressed as the mean ± SD or as the median (25th-75th percentile).

  • Abbreviations: AP, alkaline phosphatase; CK, creatine phosphokinase; CRP, C-reactive protien; GGT, γ-glutamyltransferase; LAP, leucine aminopeptidase.

  • *

    P < 0.05 versus baseline.

AP (U/l)211 ± 55235 ± 66250 ± 68*261 ± 62*205 ± 57
GGT (U/l)156 ± 82155 ± 82149 ± 86154 ± 90158 ± 92
LAP (U/l)19 ± 817 ± 1020 ± 1121 ± 1122 ± 10
ALT (U/l)46 ± 1644 ± 19*49 ± 1995 ± 11152 ± 24
AST (U/l)40 ± 1139 ± 1045 ± 1483 ± 7943 ± 19
Bilirubin (mg/dl)0.7 ± 0.30.8 ± 0.40.8 ± 0.50.8 ± 0.30.8 ± 0.5
IgM (g/l)3.1 ± 1.73.0 ± 1.5*3.1 ± 1.63.2 ± 1.53.2 ± 1.7
IgG (g/l)13.8 ± 3.313.9 ± 3.514.4 ± 3.414.5 ± 3.414.1 ± 4.1
IgA (g/l)2.1 ± 1.12.1 ± 1.12.2 ± 1.02.2 ± 1.02.2 ± 1.2
CK (U/l)96 ± 102104 ± 95107 ± 96126 ± 123126 ± 197
CRP (mg/l)3.7 (2.1-4.8)3.2 (2.1-6.3)5.3 (1.9-7.6)3.8 (2.3-6.2)3.1 (2.3-3.9)
Fibrinogen (mg/dl)418 ± 100445 ± 97452 ± 66435 ± 88403 ± 94
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Figure 2. Changes of serum concentrations of alkaline phosphatase (AP) at baseline versus treatment with (A) atorvastatin (ATV) 10 mg/day and (B) atorvastatin 40 mg/day and changes of serum concentrations of ALT at baseline versus (C) atorvastatin 10 mg/day and (D) atorvastatin 40 mg/day.

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Administration of low doses of atorvastatin did not influence serum aminotransferase levels. Atorvastatin 40 mg/day resulted in elevated AST and ALT levels (≈2 times the ULN) compared with baseline, although this did not reach statistical significance due to the heterogeneity of the individual ALT response shown in Fig. 2D. One patient at atorvastatin 10 mg/day (Fig. 2C) and 4 patients at atorvastatin 40 mg/day (Fig. 2D) showed a profound (>100% of baseline) increase of ALT. In 1 patient treatment had to be discontinued because of an ALT increase 2-fold above baseline at atorvastatin 10 mg/day and 2 patients showed ALT elevations 3-fold above the ULN at the end of atorvastatin 40 mg/day treatment. It is important to note that the vast majority of study participants had only a slight increase or even a decrease of ALT during treatment (Fig. 2C-D).

Effects of Atorvastatin on Serum Bile Acid Composition.

Total bile acid serum levels, levels of unconjugated as well as taurine- and glycine-conjugated cholic acid, deoxycholic acid, chenodeoxycholic acid, lithocholic acid, UDCA were not significantly influenced by statin therapy (Table 3).

Table 3. Serum Bile Acid Composition of Patients with PBC
 Baseline (Week 0)Atorvastatin 10 mg/day (Week 4)Atorvastatin 20 mg/day (Week 8)Atorvastatin 40 mg/day (Week 12)Follow-up (Week 20)
  • NOTE. Values are expressed as the mean ± SD.

  • Abbreviations: DCA, deoxycholic acid; GCA, glcyo-cholic acid; GCDCA, glcyo-chenodeoxycholic acid; GDCA, glcyo-deoxycholic acid; GLCA, glyco-lithocholic acid; GUDCA, glcyo-ursodeoxycholic acid; TCA, tauro-cholic acid; TUDCA, tauro-ursodeoxycholic acid; UDCA, ursodeoxycholic acid.

  • *

    *P < 0.05 versus baseline.

TUDCA (ng/ml)130 ± 12495 ± 9567 ± 5688 ± 80168 ± 184
TCA (ng/ml)88 ± 144103 ± 14680 ± 158374 ± 597351 ± 550
GCA (ng/ml)151 ± 13989 ± 93*109 ± 126150 ± 178126 ± 170
GUDCA (ng/ml)1,269 ± 1,520911 ± 1,000904 ± 8571,153 ± 1,270837 ± 980
GCDCA (ng/ml)352 ± 373219 ± 204249 ± 246313 ± 292232 ± 299
GDCA (ng/ml)177 ± 167148 ± 83130 ± 162122 ± 189137 ± 173
GLCA (ng/ml)42 ± 3736 ± 1138 ± 1634 ± 1035 ± 13
UDCA (ng/ml)467 ± 565670 ± 645222 ± 209345 ± 328368 ± 490
DCA (ng/ml)47 ± 4949 ± 2931 ± 3366 ± 11035 ± 37

Effects of Atorvastatin on Serum Lipids and Lipoproteins.

The recruited PBC patients were hypercholesterolemic with a mean value of baseline LDL cholesterol (LDL-C) of 180 mg/dl (Table 4). Atorvastatin 10 mg/day significantly reduced LDL-C by 41%. The maximal LDL-C–lowering effect (≈49%) was achieved at atorvastatin 40 mg/day. Total apolipoprotein B and apolipoprotein B in LDL were significantly decreased (up to 48%) by atorvastatin. In line with this observation, significantly lower concentrations of total cholesterol were found during treatment. In addition, levels of LDL triglycerides were significantly decreased (up to 25%) during therapy, while no significant changes were observed in concentrations of very LDL cholesterol and very LDL triglycerides. Accordingly, total triglycerides were significantly decreased after administration of atorvastatin, except for the lowest dose. PBC patients had high concentrations of high-density lipoprotein cholesterol (HDL-C) at baseline (Table 4). HDL-C remained unchanged, whereas levels of apolipoprotein AI were reduced at atorvastatin 20 mg/day and 40 mg/day.

Table 4. Serum Lipids and Lipoproteins of Patients with PBC
 Baseline (Week 0)Atorvastatin 10 mg/day (Week 4)Atorvastatin 20 mg/day (Week 8)Atorvastatin 40 mg/day (Week 12)Follow-up (Week 20)
  • NOTE. Values are the mean ± SD or as the median (25th-75th percentile).

  • *

    P < 0.001 versus baseline.

  • P < 0.05 versus baseline.

Cholesterol (mg/dl)237 ± 48170 ± 37*159 ± 27*156 ± 45*244 ± 62
Triglycerides (mg/dl)106 ± 4788 ± 3686 ± 2591 ± 46108 ± 39
Phospholipids (mg/dl)300 ± 50245 ± 53*236 ± 39*236 ± 54*304 ± 67
Apolipoprotein AI (mg/dl)188 ± 20180 ± 32178 ± 24*174 ± 24188 ± 32
Apolipoprotein B (mg/dl)115 ± 2975 ± 18*68 ± 16*66 ± 27*117 ± 35
Lipoprotein(a) (mg/dl)31 (20-45)26 (22-41)28 (18-52)31 (22-40)23 (19-47)
Very LDL cholesterol (mg/dl)7 ± 1114 ± 911 ± 1310 ± 1513 ± 14
Very LDL triglycerides (mg/dl)55 ± 3856 ± 2547 ± 1852 ± 4162 ± 26
LDL cholesterol (mg/dl)180 ± 63107 ± 27*93 ± 20*91 ± 41*171 ± 63
LDL triglycerides (mg/dl)36 ± 1128 ± 728 ± 827 ± 8*31 ± 15
LDL apoB (mg/dl)120 ± 4074 ± 16*64 ± 16*63 ± 24*113 ± 38
HDL cholesterol (mg/dl)69 ± 1167 ± 1666 ± 1962 ± 965 ± 13

Effects of Atorvastatin on Mevalonic Acid, Cholesterol Precursors, and Metabolites.

No significant changes were observed in mevalonic acid levels during statin treatment (Table 5). Atorvastatin 10 mg/day significantly reduced the precursors of cholesterol biosynthesis such as lanosterol, desmosterol, and lathosterol by 67%, 42%, and 62%, respectively (Table 5). A more powerful reduction of these sterols was achieved by atorvastatin 40 mg/day. A similar significant decrease of cholesterol metabolite concentrations (cholestanol, 7-hydroxysterol, and 27-hydroxysterol) was found during statin therapy. However, atorvastatin had no statistically significant effect on phytosterols like campesterol, sitosterol, stigmasterol, and brassicasterol (data not shown).

Table 5. Mevalonic Acid, Cholesterol Precursors, and Metabolites of Patients with PBC
 Baseline (Week 0)Atorvastatin 10 mg/day (Week 4)Atorvastatin 20 mg/day (Week 8)Atorvastatin 40 mg/day (Week 12)Follow-up (Week 20)
  • NOTE. Values are expressed as the mean ± SD.

  • *

    P < 0.05 versus baseline.

  • P < 0.001 versus baseline.

Mevalonic acid (ng/ml)2.8 ± 3.03.7 ± 3.15.7 ± 4.12.8 ± 1.82.9 ± 2.9
Lanosterol (ng/ml)99 ± 4333 ± 11*23 ± 12*28 ± 23*68 ± 33
Desmosterol (ng/ml)1,401 ± 712816 ± 354*563 ± 230*602 ± 423*1,395 ± 672
Lathosterol (ng/ml)2,738 ± 1,2421,053 ± 432671 ± 273790 ± 786*2,403 ± 1,050
Cholestanol (ng/ml)5,650 ± 1,4524,843 ± 1,360*3,909 ± 926*3,873 ± 1,100*5,282 ± 1,700
27-OH-cholesterol (ng/ml)273 ± 89147 ± 61*125 ± 65*156 ± 47*203 ± 107
7-OH-cholesterol (ng/ml)51 ± 2822 ± 19*23 ± 12*32 ± 3226 ± 22

Effects of Atorvastatin on Serum Inflammatory and Immune Markers.

Atorvastatin significantly reduced levels of IgM at the lowest dose of atorvastatin (Table 2). Other immunoglobulins, antimitochondrial antibody titers, C-reactive protein, and fibrinogen did not change significantly.

Discussion

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

In the present study, we examined atorvastatin as novel nuclear receptor–targeted therapeutic approach in patients with PBC and an incomplete biochemical response to UDCA.6 Based on experimental findings in cholestatic animals, we hypothesized that activation of nuclear receptors by atorvastatin may improve cholestasis via modulation of bile formation and induction of hepatic bile acid/bilirubin metabolizing and detoxifying enzymes.31, 32 Statins have previously been shown to act, at least in part, as agonists for the nuclear pregnane X receptor.41 Stimulation of pregnane X receptor/sterol X receptor reduces bilirubin and serum bile acid levels in humans and rodents.31, 42 Moreover, statins have been shown to stimulate biliary excretion of phospholipids34, 35 that may further protect bile ducts from immunomediated injury in PBC.43, 44 This may be explained by activation of the nuclear peroxisome proliferator–activated receptor-α,45 which is predicted to modulate biliary bile acid/phospholipid ratio via increased biliary phospholipid secretion and increased cholangiocellular reabsorption of biliary bile acids,31, 46 resulting in less aggressive bile.

In our study, however, AP as a primary efficacy parameter and marker of cholestasis did not improve during active treatment. Surprisingly, serum AP levels even increased by approximately 24% at atorvastatin 40 mg/day. However, other biochemical serum markers of cholestasis such as γ-glutamyltransferase, leucine aminopeptidase, and serum bile acid levels remained unchanged, suggesting that this finding may instead reflect a mechanism specific for AP and not necessarily indicate aggravation of biochemical cholestasis. As such, statins could induce AP expression via activation of nuclear receptors such as the vitamin D receptor.47, 48 In contrast to Ritzel et al,30 who reported an improvement of serum AP and γ-glutamyltransferase levels, our study was restricted to patients with an incomplete biochemical response to UDCA who may represent a selected difficult-to-treat patient subpopulation. We focused on this patient group because such patients remain at increased risk for disease progression5 and may be at the most urgent need for development of novel therapeutic regimens. However, the differing effects between simvastatin and atorvastatin may also be due to the use of a different compound.

Statin therapy did not affect serum bilirubin and bile acid concentrations. However, it has to be kept in mind that patients with early PBC stage recruited in our study, still have normal bilirubin and bile acid levels. Therefore, it cannot be excluded that statins could have an impact on bile acid and bilirubin detoxification in more advanced PBC with elevated serum bile acid and bilirubin levels.

Statins are frequently prescribed drugs in Western countries and generally have an excellent safety profile. However, these drugs have long been considered at least relatively contraindicated in patients with underlying chronic liver disease. Although there are encouraging data about safety on statins in chronic liver disorders and elevated ALT levels, in particular with fatty liver,21, 22, 25 little is known about their safety in cholestatic liver diseases. In this study, patients with early-stage PBC developed only mildly elevated aminotransferases, and statins were generally well tolerated. Nevertheless, individual patients may be at risk, because atorvastatin treatment had to be discontinued in 1 out of 15 patients due to an ALT level 2-fold above baseline at atorvastatin 10 mg/day, and 2 patients showed ALT elevations more than 3 times the ULN at the end of atorvastatin 40 mg/day treatment. Our criteria for discontinuation (more than 2-fold above baseline) may be considered very stringent, but they were chosen given the lack of experience of statin therapy in patients with cholestatic liver diseases at the time of study initiation. Interestingly, serum aminotransferase elevations were not observed in PBC patients treated with simvastatin,30 which may indicate a lower potential for hepatotoxicity of this drug.24 However, the number of patients in the present and previous studies was too small for making final conclusions regarding drug tolerance in a rare condition such as PBC. Of note, statins have recently been suggested to be useful for the treatment of portal hypertension,49 and further studies will have to explore their safety in patients with advanced PBC and cirrhosis. Our results indicate that patients with PBC should be closely monitored with serial liver function tests during atorvastatin therapy.

Although the exact etiology of PBC is unknown, autoimmune-mediated bile duct injury plays a critical role.1 Antimitochondrial antibodies and elevated levels of IgM are typical for PBC.1 Of note, statins may mediate anti-inflammatory and immunomodulatory effects in other autoimmune disorders such as rheumatoid arthritis and multiple sclerosis.30, 37, 38 In the present study, atorvastatin 10 mg/day significantly decreased IgM levels, but the changes were minimal. Antimitochondrial antibody titers, C-reactive protein, and fibrinogen remained unchanged, and higher statin doses no longer had a significant effect on IgM levels. However, antimitochondrial antibodies are only surrogate parameters and may not be of pathophysiological relevance.1, 3 Because T cell response was not assessed, it cannot be excluded that long-term statin therapy (with lower doses) could have beneficial immunomodulatory effects on the course of PBC which may deserve further investigations.

Statin therapy may also be indicated for treatment of dyslipidemia associated with PBC, although this remains controversial. Because most early diagnosed PBC patients have a slow progression of their underlying liver disease, cardiovascular risk factors may become more and more relevant as prognostic factors. Hypercholesterolemia may constitute a major risk factor for cardiovascular disease in PBC.50 Early and intermediate stages of PBC have mildly elevated very LDL-C and LDL-C and markedly increased HDL-C and are associated with an increased cardiovascular risk, while advanced PBC exhibits markedly elevated LDL-C and decreased HDL-C.8, 12, 13 Hypercholesterolemia seems to be associated with increased carotid artery intima media thickness and carotid stenosis in hypertensive or older PBC patients who will benefit from lipid-lowering medication.10 We therefore examined the lipoprotein pattern under statin therapy in our patients. Atorvastatin significantly reduced concentrations of LDL-C, one of the most important predictors of atherosclerosis and coronary artery disease. In accordance with this finding, atherogenic lipoproteins including LDL apolipoprotein B and total apolipoprotein B as well as total cholesterol were also significantly decreased during lipid-lowering therapy. Notably high levels of LDL-triglycerides, in addition to elevations in LDL-C, were found in PBC patients. Recently, it was shown that alterations of LDL metabolism characterized by high LDL-triglycerides are related to coronary artery disease, systemic low-grade inflammation, and vascular damage.51 These alterations in LDL may also contribute to an unsatisfactory vascular status. Finally, PBC patients who are candidates for liver transplantation should have no pre-existing advanced stages of atherosclerosis, which may be further aggravated by subsequent immunosuppressive therapy.

In summary, this study demonstrates that atorvastatin does not improve cholestasis in patients with early-stage PBC not responding to standard UDCA treatment. In these patients, low-dose statin therapy effectively lowered serum cholesterol levels. Future clinical studies will have to determine the safety and efficacy of long-term treatment with low-dose statins (including drugs alternative to atorvastatin) on dyslipidemia, cardiovascular risk factors, and vascular function in patients with PBC.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References

The excellent technical assistance of Sabine Kern and Sabine Paulitsch is gratefully acknowledged. We also thank the Pharmacy of the University Hospital Graz, for the preparation of the study medication.

References

  1. Top of page
  2. Abstract
  3. Patients and Methods
  4. Results
  5. Discussion
  6. Acknowledgements
  7. References
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    Trauner M, Boyer JL. Cholestatic syndromes. Curr Opin Gastroenterol 2003; 19: 216-231.
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    Levy C, Lindor KD. Current management of primary biliary cirrhosis and primary sclerosing cholangitis. J Hepatol 2003; 38( Suppl 1): S24-S37.
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    Paumgartner G, Beuers U. Mechanisms of action and therapeutic efficacy of ursodeoxycholic acid in cholestatic liver disease. Clin Liver Dis 2004; 8: 67-81.
  • 5
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