The relief of bone pain in primary biliary cirrhosis with calcium infusions

Symptoms of PBC - Pathophysiology and management

Primary biliary cholangitis is a chronic cholestatic liver disease characterised by progressive bile duct damage and, ultimately, biliary cirrhosis. Though up to fifty percent of the patients can be asymptomatic at presentation, symptoms when present are frequently debilitating with significant impact on quality of life and functional status. Characteristic symptoms include pruritus, fatigue and an increasingly recognised mild cognitive impairment. With the exception of pruritus, the "classic" cholestatic symptom, therapeutic options to treat PBC related symptoms are currently limited leaving patients with often significant residual problems. Symptoms can frequently contribute to depression and social isolation further compounding the quality of life impairment. There is need to better understand the current therapeutic options available in order to optimise their use, and to explore newer avenues to understand the pathophysiology of the symptom-generating processed in PBC in order to develop new therapies.

Mycophenolate mofetil for the treatment of primary biliary cirrhosis in patients with an incomplete response to ursodeoxycholic acid

BACKGROUND & AIMS

Despite evidence for therapeutic efficacy with ursodeoxycholic acid (UDCA) in primary biliary cirrhosis (PBC), only 30-50% of patients achieve complete biochemical remission within 1 year of therapy. Mycophenolate mofetil (MMF) is an immunosuppressive medication that inhibits T and B lymphocyte proliferation. The aim of this investigation was to determine the safety and estimated efficacy of MMF in patients with PBC.

METHODS

Twenty-five patients with incomplete responses to UDCA (defined as persistent elevation of serum alkaline phosphatase > or =2 times the upper limit of normal) received MMF 1 g daily to a maximum of 3 g daily with UDCA (13-15 mg/kg per day) for 1 year. Liver biochemistries were determined at 3-month intervals with Mayo Risk Score calculated at baseline and end of therapy.

RESULTS

Nineteen (76%) patients completed 1 year of therapy. Despite improvements in serum alkaline phosphatase (920 +/- 308 vs. 709 +/- 242 IU/L, P = 0.001) and AST (65 +/- 31 vs. 51 +/- 19 IU/L, P = 0.007) levels, these findings were clinically insignificant. Exploratory analysis revealed a strong correlation between advanced PBC defined by higher Mayo Risk Score and reduction in serum alkaline phosphatase levels (r = -0.74, P = 0.006). Six patients (24%) did not complete therapy; adverse drug events were responsible for study withdrawal in 3 individuals. Adverse reactions that resolved spontaneously or by dose reduction occurred in 13 patients.

CONCLUSIONS

MMF is not associated with important clinical benefits in PBC based on the results of this pilot investigation.

Transdermal hormone replacement therapy improves vertebral bone density in primary biliary cirrhosis: results of a 1-year controlled trial

BACKGROUND

Retrospective studies have suggested that hormone replacement therapy may reduce the rate of bone loss in primary biliary cirrhosis, but no controlled data are available.

METHODS

Forty-two post-menopausal women with primary biliary cirrhosis were treated with calcium and vitamin D, either alone (n = 21) or together with transdermal hormone replacement therapy (n = 21). Bone densitometry was performed at baseline and at 1 year, and serum and urinary markers of bone turnover were measured at three-monthly intervals.

RESULTS

At entry, 17 patients (40%) had spinal or femoral osteopenia (T score - 1 to - 2.5) and nine (21%) had osteoporosis (T < - 2.5). In those given hormone replacement therapy, there was a significant decrease in the mean urinary deoxypyridinoline :creatinine ratios at 3 months (7.8 vs. 6.1 nm/mm creatinine for no hormone replacement therapy vs. hormone replacement therapy; P = 0.04) and a 48% reduction in urinary calcium excretion at 1 year (0.66 vs. 0.32 mm/mm creatinine; P = 0.01). Repeat bone densitometry at 1 year revealed a 2.25% increase in the hormone replacement therapy group (P = 0.02), compared with a non-significant 0.87% decrease in L2-L4 bone mineral density in those not given hormone replacement therapy. Both treatment regimens were well tolerated, with no increase in cholestasis.

CONCLUSIONS

Compared with calcium and vitamin D alone, supplemental treatment with transdermal hormone replacement therapy for 1 year improved the vertebral bone density and urinary markers of bone turnover in post-menopausal women with primary biliary cirrhosis.

Management of osteoporosis in primary biliary cirrhosis

Osteoporosis is not a significant problem in the majority of patients with primary biliary cirrhosis (PBC). However, substantial bone-related morbidity may occur in patients with advanced disease, in particular after liver transplantation. The cause of osteoporosis in PBC is multifactorial, and pathophysiological mechanisms specifically related to PBC have not been defined. In general, the principles of management followed in post-menopausal osteoporosis also apply in chronic liver disease. Dual energy X-ray absorptiometry is currently the method of choice for monitoring bone mineral density. Avoidance of conditions with potential negative effects on bone mass, and maintaining adequate serum vitamin D levels and calcium intake form the cornerstone in preventing osteoporosis. Bisphosphonates are the most logical choice when specific medical treatment of PBC-associated osteoporosis is indicated, as well as for preventing bone loss during glucocorticoid treatment and after liver transplantation. Recent studies suggest that active vitamin D analogues are effective alternatives in the post-transplant setting.

Primary biliary cirrhosis

Primary biliary cirrhosis is a chronic liver disease of unknown etiology characterized by slowly progressive intrahepatic cholestasis due to an inflammatory destruction of small intrahepatic bile ducts. The clinical course of PBC is variable ranging from a few years in rapidly progressive cases to a normal life-expectancy in a proportion of asymptomatic cases. The typical patient is a middle-aged woman who may present with pruritus, increasing pigmentation of the skin, and eventually jaundice. The level of serum alkaline phosphatase is almost invariably elevated, serum mitochondrial antibodies are present in more than 90 per cent, and an elevated serum IgM is usually present. PBC is associated with many immunologic abnormalities and appears to be a classic autoimmune disease. Some of the immune defects may be epiphenomena; others such as a marked defect in suppressor T cell function seem to be related to the pathogenesis of the disease. All drug therapy that is aimed at slowing the disease process is experimental. A place for immunosuppressive drugs in the management of PBC would be anticipated. However, no drug has to date been definitively shown to have a beneficial effect on the disease. Currently, the main treatments used are aimed at preventing or correcting the complications of intractable cholestasis. Patients with PBC and evidence of hepatic decompensation and/or poor quality of life make good candidates for liver transplantation. The current aim of therapy is to find an effective regime of immunosuppression that will make hepatic transplantation redundant for this disease.

Metabolic bone disease in primary biliary cirrhosis at presentation

Metabolic bone disease, particularly osteoporosis, is a complication of advanced primary biliary cirrhosis, but the extent of the problem is unclear. We present 33 patients who were investigated for bone disease at the time of diagnosis of their liver disease and who had received no prior treatment likely to influence their bones. Iliac crest bone biopsy showed no patient with osteoporosis, and mild osteomalacic changes in 1 patient. Slight elevations in appositional rate, osteoid volume, and resorption surface were compatible with a state of high bone turnover. Photon absorptiometry revealed a low forearm bone mineral content in 3 of 25 patients, calcium absorption was below normal in 14 of 24 patients, and there was evidence of fat malabsorption in 11 of 25 patients. Five patients also had low serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D. Thus, little evidence of significant metabolic bone disease was found in this group by these methods, but abnormalities were seen, such as poor calcium absorption, that may predispose to its later development.

Vitamin D deficiency, osteomalacia, and primary biliary cirrhosis. Response to orally administered vitamin D3

Five patients with primary biliary cirrhosis and vitamin D deficiency (serum 25-hydroxyvitamin D less than 6 ng/ml) are presented. All patients had low serum 24,25-dihydroxyvitamin D3 concentrations. Three patients had histological osteomalacia, negative calcium balance, and subnormal serum 1,25-dihydroxyvitamin D3. Malabsorption of a standard dose of [3H]vitamin D3 was found in three of four patients with steatorrhea, enabling the effective dose of vitamin D3 given to be calculated. Oral vitamin D3 400-4000 IU/day (effectively 400-1860 IU/day) resulted in a return to normal of the serum vitamin D metabolites, correction of the impaired intestinal calcium absorption and healing of the osteomalacia. Increases in serum calcium, phosphate, and the renal tubular reabsorption of phosphate occurred with a concomitant decrease in serum parathyroid hormone. It is suggested that osteomalacia in primary biliary cirrhosis is the end result of vitamin D deficiency; the hepatic and renal hydroxylations of vitamin D are normal and target tissues are responsive to endogenously produced metabolites of vitamin D.

Vitamin D metabolism in acute and chronic cholestasis

To study the effects of acute and chronic cholestasis on vitamin D metabolism we investigated six cases of acute extrahepatic obstructive jaundice and eight cases of primary biliary cirrhosis (PBC) (three supplemented with vitamin D). Plasma 25-hydroxyvitamin D (25OHD) was low in the patients with PBC unsupplemented with vitamin D but normal in obstructive jaundice. None of the patients with PBC showed radiological or histological evidence of osteomalacia. In PBC, dietary intake of vitamin D was low but response to ultra-violet irradiation of the skin was normal even in those with a considerably raised serum bilirubin. Patients with PBC or obstructive jaundice had low levels of 25 hydroxyvitamin D binding protein which correlated with the serum albumin. The half-life of intravenously injected (3)H vitamin D(3) ((3)HD(3)) and the subsequent production of (3)H 25OHD were normal in all the patients with obstructive jaundice and in most with PBC. The two patients with PBC who produced less (3)H 25OHD than expected were receiving vitamin D supplements. The urinary tritium ((3)H) excretion after the injection of (3)HD(3) correlated with the serum bilirubin. After the injection of (3)H 25OHD(3) the urinary excretion of (3)H was minimal and did not correlate with the serum bilirubin, suggesting that the radioactivity appearing in the urine after the (3)H vitamin D(3) injection was associated with vitamin D metabolites other than 25OHD. Factors contributing to the low plasma 25OHD in primary biliary cirrhosis may be a low dietary intake of vitamin D, inadequate exposure to ultra-violet light, and a tendency to urinary wastage of vitamin D metabolites.

Effect of oral 1,25 dihydroxycholecalciferol on calcium and phosphate malabsorption in primary biliary cirrhosis

Changes in calcium and phosphate absorption in response to treatment with small doses of oral 1,25 (OH)2D3 were studied in 10 patients with primary biliary cirrhosis by means of a combined radio-isotope technique. There was a marked improvement in the fractional rates of absorption of calcium (P less than 0.01) and phosphate (0.05 P less than 0.1) after treatment. This implies than there is no end organ unresponsiveness to the action of active Vitamin D metabolites at the intestinal level in primary biliary cirrhosis.

Parenteral 1,25-dihydroxycholecalciferol in hepatic osteomalacia

Despite regular long-term parenteral vitamin D2 treatment, four patients with biliary cirrhosis had multiple symptoms of bone disease and bone biopsy specimens showed osteomalacia without osteoporosis. Three patients also had a proximal myopathy. Plasma calcium values (after correction for albumin), phosphorus, magnesium, and serum 25-hydroxy-vitamin D were within normal limits. Treatment with 1,25-dihydroxy-cholecalciferol (1,25-(OH)2D3) relieved symptoms in three of the four patients and improved those in the fourth. Histological examination of bone showed improvement in all four patients, but serum and urinary biochemical changes were not pronounced. We conclude that 1,25-(0H)2D3 treatment has a beneficial effect on bone and muscle in hepatic osteomalacia, either because vitamin D 1-hydroxylation fails in biliary cirrhosis or because hepatic osteomalacia is resistant to vitamin D2 metabolites.

Absorption, hydroxylation, and excretion of vitamin D3 in primary biliary cirrhosis

Oral vitamin D3 was poorly absorbed by 4 out of 6 patients with primary biliary cirrhosis; absorption was negatively correlated with faecal fat excretion. 25-hydroxylation of vitamin D3 given by mouth or intravenously was not impaired in the patients compared with controls of similar vitamin-D nutritional status. Urinary radioactivity derived from the intravenous dose of vitamin D3 was significantly greater in patients than in controls and was positively correlated with the serum-bilirubin concentration. Excretion in the urine may lead to loss of administered and endogenous vitamin D and thus contribute to vitamin-D deficiency in patients with primary biliary cirrhosis.

25-Hydroxylation of vitamin D in primary biliary cirrhosis

The ability to 25-hydroxylate vitamin D was investigated in thirty-nine patients with symptomatic primary biliary cirrhosis (P.B.C.). In seven previously untreated patients serum-25-hydroxy-vitamin-D (25-OHD) concentration increased after regular monthly injections of vitamin D. After a single injection of vitamin D in eight P.B.C. patients serum-25-OHD did not change significantly over 12 days; in contrast there were significant increases in eight normal subjects and in seven patients with nutritional osteomalacia. Twenty-three of twenty-five P.B.C. patients on regular vitamin-D therapy had normal serum-25-OHD values. These results indicate that serum-25-OHD concentrations become normal in P.B.C. if adequate amounts of vitamin D are presented to the liver as substrate.

Renal handling of sodium, water and divalent ions in patients with primary biliary cirrhosis

1) Fluid retention and ascites are rarely seen in patients with primary biliary cirrhosis (PBC). In an attempt to clarify this clinical observation, renal handling of sodium, water and divalent ions was studied during extracellular volume expansion (ECVE) and maximal suppression of antidiuretic hormone (ADH) secretion in 5 patients with PBC and 9 normal subjects. 2) Mean fractional excretion of sodium, water, phosphate and calculated fractional distal delivery of sodium were significantly greater in patients with PBC as compared with normal controls. Fractional CH20 for given fractional urine flow was similar in patients with PBC and normals. 3) The data suggest that patients with PBC have a greater diminution of proximal tubular reabsorption of sodium in response to ECVE than controls. This augmented elimination of salt during ECVE in patients with PBC may explain the rarity of ascites and edema in this type of cirrhosis.

Comparison of vitamin D and 25-hydroxy-vitamin-D in the therapy of primary biliary cirrhosis

Skeletal demineralisation and low serum concentrations of 25-hydroxy-vitamin-D were observed in patients with primary biliary cirrhosis. Neither oral nor parenteral vitamin-D increased 25-hydroxy-vitamin-D in serum or prevented further skeletal demineralisation. In contrast, oral 25-hydroxy-vitamin-D increased serum-25-hydroxy-vitamin D concentrations in all patients, and bone mineral content either improved or stabilised in all but one, 25-hydroxy-vitamin-D may be the preferred form of vitamin-D therapy in primary biliary cirrhosis.