Oral Bile Acid Treatment in Two Japanese Patients With Zellweger Syndrome

Abstract

Zellweger syndrome is an autosomal recessive disease manifest as multiple congenital anomalies that include hypotonia, psychomotor retardation, craniofacial dysmorphism, and hepatomegaly with liver dysfunction. This well-characterized disease has been shown to result from the absence of functional peroxisomes. Liver dysfunction in Zellweger syndrome, attributable to overproduction and accumulation of cholestanoic acids, may be exacerbated by diminished primary bile acid synthesis. Setchell et al. (1) described clinical and biochemical responses in a patient with Zellweger syndrome who was treated with primary bile acids. We therefore examined the clinical and biochemical responses to chenodeoxycholic acid (CDCA) or ursodeoxycholic acid (UDCA) treatment in two Japanese patients with Zellweger syndrome. We paid particular attention to serum and urinary bile acid profiles before and during CDCA or UDCA treatment. CASE REPORTS Patient 1 This female patient was the second infant born to parents who are second cousins. The first child had died of Zellweger syndrome at 5 months of age. This second infant had a normal delivery after 37 weeks and 5 days of gestation. Birth weight was 2360 g. At birth, the infant had pitting edema, profound hypotonia, and tachypnea in addition to the abnormal skull shape and appearance typical of Zellweger syndrome. Radiographs of the knees revealed typical patellar calcifications. Routine laboratory studies added no significant information. In serum, excessive very long-chain fatty acids were evident, with markedly elevated C26/C22 (0.508) and C24/C22 ratios (1.535), consistent with a defect in peroxisomal fatty acid oxidation. Increased amounts of organic acids, specifically p-hydroxyphenyllactate, p-hydroxyphenylpyruvate, and 3–6-epodeoxytetradecanediate, were identified in the urine. We detected the cholestanoic acids 3α,7α,12α-trihydroxy-5β-cholestan-26-oic acid (THCA) and 3α,7α-dihydroxy-5β-cholestan-26-oic acid (DHCA) in the urine by bile acid analysis using gas chromatography mass spectrometry (GC-MS). Hepatomegaly and signs of liver dysfunction became apparent. Serum alanine aminotransferase (ALT; 90 IU/L), aspartate aminotransferase (AST; 264 IU/L), and total bilirubin (15.3 mg/dL) concentrations were increased markedly. Beginning at 1 month of age, the patient was given 100 mg/kg docosahexanoic acid (DHA) daily. CDCA treatment was given at 3 months of age at 15 mg/kg daily. Thereafter, total bilirubin gradually increased. At that point, CDCA treatment was discontinued; although total bilirubin decreased, transaminase activities increased. Therefore, we started UDCA treatment (10 mg/kg daily). At 10 months of age, the patient died of respiratory and liver failure. Patient 2 This male patient was the first infant born to healthy parents with no consanguinity. His delivery was normal after 38 weeks of gestation. Birth weight was 2616 g, and length was 47 cm. At birth, he had profound hypotonia, and subsequently he experienced jaundice and cream-colored stools. At 23 days of age, laboratory investigations showed normal values except for increased serum ALT (112 IU/L), AST (350 IU/L), and total bilirubin concentrations (5.1 mg/dL). Hepatobiliary scintigraphy showed no gastrointestinal excretion. He was diagnosed with neonatal cholestatic syndrome, and open liver biopsy was performed immediately. After biopsy, UDCA treatment (10 mg/kg daily) was started. Histologic findings included severe cholestasis and a moderate increase in fibrosis in the portal area. At 5 months of age, urinary bile acid analysis was performed by GC-MS; we detected the cholestanoic acids THCA and DHCA. We then diagnosed the patient with Zellweger syndrome. Radiographs showed typical calcification of the patella. Patient serum exhibited markedly elevated C26/C22 (0.118), C25/C22 (0.109), and C24/C22 ratios (2.330) and an excess of very-long-chain fatty acids. After diagnosis, we initiated CDCA (5 mg/kg daily) and DHA (50 mg/kg daily) combined with UDCA treatment (10 mg/kg daily). Abnormal liver function improved after oral bile acid treatment, and therefore we temporarily interrupted treatment. However, the serum activities of transaminases gradually increased. We then started CDCA treatment (5 mg/kg daily), followed by combined CDCA (5 mg/kg daily) and UDCA (10 mg/kg daily) treatment. However, at 7 months of age, the patient died of respiratory failure. Associations between oral bile acid treatment and laboratory findings including serum ALT and total bilirubin in both patients are discussed below. We did not perform analysis of pipecolic acid. Bile Acid Analysis Serum and urine samples were obtained to examine the effect of CDCA or UDCA during oral bile acid treatment. Samples were stored at −25°C until analysis. The concentration of individual bile acids in the urine was corrected for creatinine (Cr) concentration in each subject and expressed as micromoles per millimole of Cr. In the standard procedure, samples of human biologic fluids were routinely prepared for GC-MS analysis as described previously (2). Serum Very-long-chain Fatty Acids In patient 1, the C24/C22 ratio (1.535) before DHA treatment exceeded the normal range (0.628 to 0.977), and increased to 2.294 during DHA treatment. However, the C24/C22 ratio decreased modestly to 2.055 after addition of CDCA treatment at 3 months of age. No significant changes were seen subsequently in this ratio. In patient 2, the C24/C22 ratio decreased somewhat from 2.330 to 1.946 after 1 week of DHA and CDCA treatment, and further assays were not performed. Serum ALT, Total Bilirubin, and Bile Acids and Urinary Bile Acids Before treatment in patient 1 (Fig. 1), we detected large quantities of THCA and DHCA in the urine (combined amount, 9.59 μmol/mmol Cr, representing 50.7% of total bile acids) and the serum (52.45 μmol/L, 82.9%), with the major cholestanoic acid being THCA. During CDCA treatment alone (15 mg/kg daily), concentrations of CDCA increased remarkably in the urine (from 1.46 to 343.44 μmol/mmol Cr, from 7.7% of total bile acids to 84.2%) and in the serum (from 8.05 to 311.72 μmol/L; from 12.7% to 96.5%). Considered together, THCA and DHCA decreased remarkably in the urine (from 52.45 to 5.79 μmol/mmol Cr, from 82.9% of total bile acids to 1.8%) and in the serum (from 9.59 to 0.88 μmol/L, from 50.7% to 0.2%). However, total bilirubin increased from 17.1 to 36.0 mg/dL. At that point, we stopped CDCA treatment and total bilirubin decreased but ALT increased. At that time, concentrations of THCA and DHCA in the serum again were increased, and the main cholestanoic acid was DHCA. Therefore, we initiated UDCA treatment alone (10 mg/kg daily). Again considered together, concentrations of THCA and DHCA in the serum decreased from 43.74 μmol/L (95.8% of total bile acids) to 36.56 μmol/L (46.6%). However, total bile acids in the serum increased from 45.65 μmol/L to 78.39 μmol/L during UDCA treatment alone.FIG. 1.: Time course of laboratory findings in patient 1. CDCA, chenodeoxycholic acid; T.Bil, total bilirubin; ALT, alanine aminotransferase; UDCA, ursodeoxycholic acid; THCA, 3α,7α,12α-trihydroxy-5β-cholestan-26-oic acid; DHCA, 3α,7α-dihydroxy-5β-cholestan-26-oic acid; TBA, total bile acids; Cr, creatinine.In patient 2 (Fig. 2), we detected large amounts of THCA and DHCA in the serum (together, 7.21 μmol/L and 33.3% of total bile acids) before treatment. After UDCA treatment alone (10 mg/kg daily), concentrations of THCA and DHCA in the serum decreased remarkably (together, 1.29 μmol/L, representing 1.4%). Moreover, after combined treatment with UDCA and CDCA (5 mg/kg daily), concentrations of THCA and DHCA decreased remarkably in the urine (together, from 7.01 μmol/mmol or 26.2% to 4.31 μmol/mmol Cr or 12.7%) and in serum (from 1.29 μmol/L or 1.4% to 0.30 μmol/L or 0.9%). Total bilirubin and ALT also decreased from 1.1 to mg/dL 0.5 mg/dL and from 81 IU/L to 39 IU/L, respectively. At that point, treatment was suspended, but serum ALT increased, along with the percentage of THCA in the total bile acids in the urine and the serum. We resumed treatment with CDCA, and the percentage of THCA in the total bile acids decreased, but serum ALT continued to increase. Finally, we returned to combined CDCA and UDCA treatment. As a result, serum concentrations of ALT gradually decreased (from 401 to 82 IU/L), as did THCA (from 1.16 μmol/L or 3.0% of total bile acids to 0.21 μmol/L or 1.3%).FIG. 2.: Time course of laboratory findings in patient 2. CDCA, chenodeoxycholic acid; T.Bil, total bilirubin; ALT, alanine aminotransferase; UDCA, ursodeoxycholic acid; THCA, 3α,7α,12α-trihydroxy-5β-cholestan-26-oic acid; DHCA, 3α,7α-dihydroxy-5β-cholestan-26-oic acid; TBA, total bile acids; Cr, creatinine.DISCUSSION Balistreri (3) and Jacquemin et al. (4) suggested that UDCA treatment may be effective in treating children with progressive familial intrahepatic cholestasis or inborn errors of bile acid biosynthesis. The use of UDCA as a therapeutic agent in such cases is based on the hypothesis that this nontoxic hydrophilic bile acid may reverse the potential hepatotoxicity of endogenous bile acids that accumulate during cholestasis. Hepatic biosynthesis of bile acids from cholesterol is moderately increased or, at worst, unchanged by administration of UDCA (5). Moreover, administration of UDCA increases the rate of biliary excretion of endogenous bile acids and limits their return to the liver by inhibiting intestinal reabsorption (6). In our patients, UDCA treatment decreased concentrations of THCA, DHCA, and total bile acids in serum and urine. Therefore, UDCA treatment may be the best choice currently available for treating liver dysfunction in Zellweger syndrome. Primary bile acids administered as replacement therapy enter the enterohepatic circulation and down-regulate activity of cholesterol 7α-hydroxylase (1,7). Details of the bile acid synthetic pathway, which are of value in understanding the basis for therapy, have been reviewed (8). In our patients, concentrations of THCA and DHCA in the serum and the urine gradually decreased after CDCA treatment (Figs. 1 and 2). Treatment with CDCA is effective in decreasing accumulation of unusual bile acids such as THCA and DHCA in hepatocytes. However, in our patients, the concentration of CDCA in serum and urine increased gradually during CDCA treatment, and patients experienced severe liver dysfunction. Dosage of CDCA may be an important issue. In patient 1, activity of 12α-hydroxylase presumably was decreased due to liver dysfunction after CDCA treatment, and concentrations of CDCA and DHCA were increased to a greater extent than those of cholic acid and THCA in the serum. Unfortunately, improvement of growth and neurologic status was not achieved during combined oral bile acid and DHA treatment. Therefore, irreversible toxicity to the brain and liver from DHCA and THCA may have occurred. According to Setchell et al. (1), liver dysfunction due to the accumulation of the cholestanoic acids THDA and DHCA in a patient with Zellweger syndrome was improved with primary bile acid therapy. When we tried CDCA treatment for a Japanese patient with Zellweger syndrome (patient 1), concentrations of cholestanoic acids in serum and urine were decreased remarkably by CDCA treatment alone (15 mg/kg daily). Concentrations of CDCA, and its relative contribution to total bile acids, increased remarkably in serum and urine. As a result, patient 1 experienced liver dysfunction with increased ALT and total bilirubin concentrations. Liver dysfunction improved somewhat after discontinuing CDCA treatment and substituting UDCA treatment (10 mg/kg daily). In another Japanese patient (patient 2), concentrations of total bile acids and cholestanoic acids in serum and urine, and increased ALT and total bilirubin, were decreased satisfactorily by UDCA treatment alone (10 mg/kg daily). Moreover, combined treatment with UDCA and CDCA (5 mg/kg daily) was more effective than either UDCA or CDCA treatment alone in decreasing concentrations of total bile acids and cholestanoic acids in serum and urine, and the combination also more effectively decreased elevation of ALT and total bilirubin. The rationale for combined treatment with UDCA and CDCA was to increase the rate of biliary excretion of endogenous bile acids by administration of UDCA, and to use CDCA administration to reduce the activity of cholesterol 7α-hydroxylase, which supplies metabolites to the blocked peroxisomal portion of the bile acid synthetic sequence. In conclusion, we suggest UDCA (10 mg/kg daily) and low-dose CDCA (5 mg/kg daily) as combined treatment for liver dysfunction in patients with Zellweger syndrome, which may prevent progressive liver dysfunction due to accumulation of cholestanoic acids in the early stage after diagnosis. Only one previous patient with Zellweger syndrome who was given oral bile acid treatment had been reported (1), and further studies of more patients are required to fully evaluate the potential of oral bile acid treatment for patients with this severe disease. These observations should include evaluation of the effect of combined UDCA and CDCA therapy on THCA and DHCA excretion with data obtained at short intervals, such as every 1 to 2 weeks, during the entire treatment protocol.