25-Hydroxylation of vitamin D in primary biliary cirrhosis

Impact of Vitamin D Status in Chronic Liver Disease

BACKGROUND

Vitamin D deficiency is extremely common in chronic liver disease (CLD) patients. Up to 93% of these patients have some degree of vitamin D insufficiency. Liver plays an important role in the metabolism and pleiotropic functions of vitamin D. Vitamin D deficiency has been associated with increased mortality, bacterial infections, portal hypertension complications, and fibrosis severity. We aimed to determine the impact of vitamin D level in CLD.

METHODS

One hundred fifty individuals consisting of 75 cirrhotic patients (cases) and 75 respective attendants (controls) were enrolled between July 2015 and July 2017. A detailed clinical and laboratory evaluation was done along with estimation of vitamin D level. Unpaired t-test and analysis of variance was used to compare difference in the level of continuous variables between different groups. Linear regression analysis was performed to analyze the correlation between vitamin D deficiency and severity of liver disease.

RESULTS

The age of patients ranged from 18 years to 69 years with mean of 48.85 ± 13.6 years in the case group and 46.57 ± 17.24 years in the control group. Out of 75 CLD patients, vitamin D deficiency (<20 ng/dl) was found in 31 (41.4%) patients, out of which 14(18.7%) suffered from severe vitamin D deficiency (<10 ng/ml). On applying analysis of variance test, there was significant difference in vitamin D level and serum albumin and serum bilirubin (P < 0.05). On linear regression, vitamin D level showed significant negative correlation with Child-Pugh score (r = -0.7379, P < 0.0001) and Model For End-Stage Liver Disease score (r = -0.6671, P < 0.0001).

CONCLUSION

Our study concluded that CLD is associated with a significantly low level of vitamin D, which was independent to patient's gender, body mass index, residence, and education level. The findings of our study suggest that awareness of serum vitamin D level in patients with CLD is important. Further studies are required to validate the importance of vitamin D levels and impact of vitamin D supplementation on CLD.

Autophagy, apoptosis, vitamin D, and vitamin D receptor in hepatocellular carcinoma associated with hepatitis C virus

The aims of this study were to investigate the interplay between autophagy and apoptosis and to investigate the association between both of autophagy and apoptosis and vitamin D and its receptor in hepatitis C virus (HCV) viral infection and its implication in the progression into hepatocellular carcinoma (HCC).A cross-sectional study where serum levels of microtubule-associated protein 1A/1B-light chain 3 (LC3); marker of autophagy, caspase-3; marker of apoptosis, vitamin D3 and vitamin D receptor (VDR) were measured in healthy subjects as well as HCV and HCV-HCC patients using enzyme-linked immunosorbent assay technique.Collectively, the liver profile revealed hepatic dysfunctions in HCV patients with or without HCC. A significant reduction in the serum concentration levels LC3 and caspase-3 were observed referring to the down regulation of autophagy and host-mediated apoptosis in HCV patients with or without HCC. Deficiency of vitamin D and decreased levels of its receptor were observed in HCV and HCV-HCC patients.The perturbation in vitamin D/VDR axis, which modulates both of autophagy and apoptosis in HCV infection, may point out to its involvement and implication in the pathogenesis of HCV infection and the development of HCV-related HCC. Therefore, supplementation with vitamin D may not be the only solution to restore the vital biological functions of vitamin D but VDR-targeted therapy may be of great importance in this respect.

Vitamin D status in patients with cirrhosis of the liver and their relatives-A case control study from North India

BACKGROUND AND AIM

Liver diseases interfere with the production of the metabolites of vitamin D required for activation, thus resulting in abnormal calcium and bone metabolism. Previous studies show inconsistent results of vitamin D level in non-cholestatic liver diseases. Our aim was to determine the prevalence of vitamin D insufficiency in cirrhosis as compared to apparently normal relatives and its relationship with etiology and severity.

METHODS

One hundred and sixty cirrhotic patients attending the Department of Gastroenterology and Hepatology, M L N Medical College, Allahabad, were enrolled, and 25-hydroxy vitamin D [25(OH)D] and calcium levels assessed. Vitamin D status was graded as insufficiency (20-30 ng/mL), deficiency (<20 ng/mL), and severe deficiency (<7 ng/mL). 25(OH)D levels of patients were compared with those of their healthy family members.

RESULTS

Forty-six percent of the normal population had 25(OH)D inadequacy, whereas 51.85% of patients with cirrhosis had 25(OH)D deficiency, and 28.12% had insufficiency. Thus, 80% of patients with cirrhosis of the liver had some form of vitamin D inadequacy. 12.5% of cirrhotics had severe vitamin D deficiency. Serum calcium (Ca⁺⁺) was not significantly different between the patients and control group. The etiology of cirrhosis had no relation with vitamin D levels. Prevalence of deficiency and insufficiency increased with increasing age and mean Child-Turcotte-Pugh and model for end-stage liver disease scores.

CONCLUSION

Vitamin D insufficiency is highly prevalent in patients with cirrhosis irrespective of etiology and significantly more common than their healthy relatives. Measurement of 25(OH) vitamin D and replacement may be considered as part of the overall management of patients with cirrhosis of the liver as well as apparently healthy individuals.

Novel insights on nutrient management of sarcopenia in elderly

Sarcopenia is defined as a syndrome characterized by progressive and generalized loss of muscle mass and strength. The more rationale approach to delay the progression of sarcopenia is based on the combination of proper nutrition, possibly associated with the use of dietary supplements and a regular exercise program. We performed a narrative literature review to evaluate the till-now evidence regarding (1) the metabolic and nutritional correlates of sarcopenia; (2) the optimum diet therapy for the treatment of these abnormalities. This review included 67 eligible studies. In addition to the well recognized link between adequate intake of proteins/amino acids and sarcopenia, the recent literature underlines that in sarcopenic elderly subjects there is an unbalance in vitamin D synthesis and in omega-6/omega-3 PUFA ratio. Given the detrimental effect of these metabolic abnormalities, a change in the lifestyle must be the cornerstone in the treatment of sarcopenia. The optimum diet therapy for the sarcopenia treatment must aim at achieving specific metabolic goals, which must be reached through accession of the elderly to specific personalized dietary program aimed at achieving and/or maintaining muscle mass; increasing their intake of fish (4 times/week) or taking omega-3 PUFA supplements; taking vitamin D supplementation, if there are low serum levels.

Common genetic variation in vitamin D metabolism is associated with liver stiffness

Recently, genome-wide studies identified genetic variants that affect serum 25-hydroxyvitamin D levels in healthy populations (rs12785878, near dehydrocholesterol reductase, DHCR7; rs10741657, at CYP2R1; and rs7041, at vitamin D binding protein, GC). Because vitamin D deficiency is associated with advanced liver disease, we hypothesized that these variants are associated with 25(OH)-vitamin D levels and liver fibrosis. Overall, 712 Caucasian patients with chronic liver diseases were included. Liver fibrosis was assessed by transient elastography (TE) and/or histology. Serum levels of 25(OH)-vitamin D were correlated with TE and fibrosis stages. Genotypes were determined using TaqMan assays and tested for association with vitamin D and liver stiffness. Serum 25(OH)-vitamin D levels were inversely correlated with liver stiffness and histology (P < 0.001). Homozygous carriers of the rare DHCR7 allele or the common CYP2R1 allele presented with reduced 25(OH)-vitamin D levels (P < 0.05). The variant rs12785878 in the DHCR7 locus was associated with liver stiffness in both patients with TE <7.0 kPa and TE between 7.0 and 9.5 kPa. 25(OH)-vitamin D levels correlated with sunshine hours at the time of inclusion (P < 0.001).

CONCLUSION

Common variation in 25(OH)-vitamin D metabolism is associated with liver stiffness in patients presenting with low to moderately increased elasticity. Although the susceptible DHCR7 genotype confers small risk, we speculate that the observed stiffness differences indicate a stronger influence of 25(OH)-vitamin D on initiation rather than progression of hepatic fibrosis.

The evaluation of bone mineral density in patients with nonalcoholic fatty liver disease

BACKGROUND AND AIM

Nonalcoholic fatty liver diseases (NAFLD) are a clinical spectrum of disorders, of which nonalcoholic steatohepatitis (NASH) is the most strongly associated with inflammation. Inflammation is a known risk factor for low bone mass in the body. The primary goal of the present study was to evaluate the association between bone mineral density and liver function in patients with NASH.

MATERIALS AND METHODS

Consenting patients with a diagnosis of NAFLD were included in the study. Extent of fatty change was graded based on ultrasonographic appearance (Grade 1, mild; Grade 2, moderate; Grade 3, severe). Bone mineral density was measured using the dual-energy x-ray absorptiometry method. ALT and hs-CRP were considered as noninvasive marker of NASH. According to ALT levels, patients were divided into two subgroups.

RESULTS

A total of 102 patients with NAFLD and 54 healthy controls participated in the study. None of the patients with NAFLD had an abnormal bone mineral density. Furthermore, there was no difference between groups with regard to serum vitamin D levels. A subgroup analysis revealed that female patients with elevated serum ALT level had significantly lower bone mineral densities and higher hsCRP levels than female patients with normal ALT levels. The difference in vitamin D levels and body mass indices between the same subgroups was statistically insignificant.

CONCLUSIONS

Simple steatosis of the liver does not affect bone mineral density. However, in a subgroup of patients with NAFLD, the presence of elevated serum ALT and hs-CRP levels, which are suggestive of NASH, was associated with lower bone mineral densities. Better understanding of the biological basis and the complex interactions between NAFLD and bone mass may help guide the clinical management of bone diseases associated with inflammation of the liver.

Prevalence of vitamin D deficiency in chronic liver disease

Vitamin D deficiency has been associated with cholestatic liver disease such as primary biliary cirrhosis. Some studies have suggested that cirrhosis can predispose patients to development of osteoporosis because of altered calcium and vitamin D homeostasis. The aim of this study was to determine the prevalence of vitamin D deficiency in patients with chronic liver disease.

METHODS

One hundred and eighteen consecutive patients (43 with hepatitis C cirrhosis, 57 with hepatitis C but no cirrhosis, 18 with nonhepatitis C-related cirrhosis) attending the University of Tennessee Hepatology Clinic had their 25-hydroxyvitamin D level measured. Severity of vitamin D deficiency was graded as mild (20-32 ng/ml), moderate (7-19 ng/ml) or severe (<7 ng/ml), normal being >32 ng/ml.

RESULTS

Of patients, 109/118 (92.4%) had some degree of vitamin D deficiency. In the hepatitis C cirrhosis group, 16.3% (7/43) had mild, 48.8% (21/43) had moderate, and 30.2% (13/43) had severe vitamin D deficiency. In the hepatitis C noncirrhotic group, 22.8% (19/57) had mild, 52.6% (30/57) had moderate, and 14% (8/57) had severe vitamin D deficiency. In the nonhepatitis C-related cirrhosis group, 38.9% (7/18) had mild, 27.8% (5/18) had moderate, and 27.8% (5/18) had severe vitamin D deficiency. Severe vitamin D deficiency (<7 ng/ml) was more common among patients with cirrhosis compared with noncirrhotics (29.5% versus 14.1%, P value=0.05). Female gender, African American race, and cirrhosis were independent predictors of severe vitamin D deficiency in chronic liver disease.

CONCLUSION

Vitamin D deficiency is universal (92%) among patients with chronic liver disease, and at least one-third of them suffer from severe vitamin D deficiency. African American females are at highest risk of vitamin D deficiency.

Current understanding of osteoporosis associated with liver disease

Osteoporosis is a common complication of many types of liver disease. Research into the pathogenesis of osteoporosis has revealed that the mechanisms of bone loss differ between different types of liver disease. This Review summarizes our current understanding of osteoporosis associated with liver disease and the new advances that have been made in this field. The different mechanisms by which cholestatic and parenchymal liver disease can lead to reduced bone mass, the prevalence of osteopenia and osteoporosis in patients with early and advanced liver disease, and the influence of osteoporotic fractures on patient survival are discussed along with the advances in our understanding of the molecular pathways associated with bone loss. The role of the CSF1-RANKL system and that of the liver molecule, oncofetal fibronectin, a protein that has traditionally been viewed as an extracellular matrix protein are also discussed. The potential impact that these advances may have for the treatment of osteoporosis associated with liver disease is also reviewed.

Vitamin D and parathyroid hormone in outpatients with noncholestatic chronic liver disease

BACKGROUND & AIMS

The liver plays a central role in vitamin D metabolism. Our aim was to determine the prevalence and type of vitamin D-parathyroid hormone (PTH) disturbance in ambulatory patients with noncholestatic chronic liver disease (CLD) and its relationship with disease severity and liver function.

METHODS

We studied 100 consecutive outpatients (63 men, 37 women; mean age, 49.0 +/- 12.1 [SD] y) with noncholestatic CLD caused by alcohol (n = 40), hepatitis C (n = 38), hepatitis B (n = 12), autoimmune hepatitis (n = 4), hemochromatosis (n = 4), and nonalcoholic steatohepatitis (n = 2); 51 patients had cirrhosis. Serum concentrations of 25-hydroxyvitamin D (25[OH]D), PTH, calcium, phosphate, magnesium, creatinine, and liver function tests were determined.

RESULTS

Serum 25(OH)D levels were inadequate in 91 patients: vitamin D deficiency (<50 nmol/L) was found in 68 patients and vitamin D insufficiency (50-80 nmol/L) was found in 23 patients. Secondary hyperparathyroidism (serum PTH, >6.8 pmol/L) was present in 16 patients. The prevalence of vitamin D deficiency was significantly higher in cirrhotic vs noncirrhotic patients (86.3% vs 49.0%; P = .0001). In Child-Pugh class C patients, 25(OH)D levels were significantly lower than in class A patients (22.7 +/- 10.0 nmol/L vs 45.8 +/- 16.8 nmol/L; P < .001). Serum 25(OH)D independently correlated with international normalized ratio (negatively; P = .018) and serum albumin (positively; P = .007). Serum 25(OH)D levels of less than 25 nmol/L predicted coagulopathy, hyperbilirubinemia, hypoalbuminemia, increased alkaline phosphatase, and anemia and thrombocytopenia.

CONCLUSIONS

Vitamin D inadequacy is common in noncholestatic CLD and correlates with disease severity, but secondary hyperparathyroidism is relatively infrequent. Management of CLD should include assessment of vitamin D status in all patients and replacement when necessary.

Vitamin D replacement for cirrhosis-related bone disease

The osteoporotic fracture rate in patients with chronic liver disease is approximately twice that of age-matched, control individuals. About 66% of patients with moderately severe cirrhosis and 96% of patients awaiting liver transplantation have vitamin D deficiency. Studies have shown a strong correlation between vitamin D deficiency and bone density, particularly in the hip. Previous studies of vitamin D therapy in cirrhosis-related bone disease have had major design flaws. Most reports and guidelines on the treatment of hepatic bone disease have concluded that vitamin D deficiency does not have a significant pathogenetic role in the development of osteoporosis in cirrhosis, and that there is no evidence for a therapeutic effect of vitamin D supplementation. Conversely, it is generally recommended that patients with cirrhosis and low bone density should receive calcium and vitamin D supplementation; yet there is a paucity of reliable data on the optimal doses to use, as well as a lack of clearly demonstrated benefit. We believe that clinical trials of vitamin D therapy in these patients with liver disease are warranted. As low-dose oral supplementation often will not normalize vitamin D levels or suppress parathyroid hormone activity in cirrhotic patients, high-dose, parenteral vitamin D might be preferable, but further long-term studies are required to assess the benefits and safety of this approach.

Evaluation and management of osteoporosis in liver disease

This article discusses the clinical importance of hepatic osteopenia, the identification of risk factors for the individual patient, and the selection of patients, timing, and methods for diagnostic screening. General supportive measures to maximize bone health should be used in all patients at risk. In addition, for the patient with established osteoporosis, specific therapeutic measures may be justified, despite the lack of adequate randomized trials of these agents in patients with hepatic osteopenia.

Calcium-parathyroid hormone-vitamin D axis and metabolic bone disease in chronic viral liver disease

BACKGROUND

The main process involved in hepatic osteodystrophy seems to be osteoporosis, but decreased 25-hydroxylation of vitamin D might lead to osteomalacia and secondary hyperparathyroidism.

METHODS AND RESULTS

We studied bone mineral density (BMD) by using DEXA-Expert Lunar, biochemical markers of bone turnover and calcium-parathyroid hormone (PTH)-vitamin D axis in 100 patients with chronic viral hepatitis secondary to hepatitis C virus: 49 non-cirrhotic (NCir) and 51 with cirrhosis (Cir) confirmed by liver biopsy and/or clinical and biochemical features. When compared to the age-matched population, 25% of the patients had low BMD at the lumbar spine (LS), 26.2% at Ward's triangle, 15.5% at the femoral neck (FN), and 20.2% at the trochanter. No difference was found either between Cir and NCir groups or between sexes. Urinary N-telopeptide was increased in 31.86% of the patients, and negatively correlated with BMD at the LS and trochanter (P < 0.02). Serum bone-specific alkaline phosphatase was elevated in 21% of the patients and negatively correlated with BMD at the trochanter and Ward's triangle (P < 0.02). Fasting 25-hydroxyvitamin D was low in only three Cir patients, with no difference between the Cir and NCir groups, but it was higher in men (51.8 +/- 16.0 ng/mL) compared to women (40.4 +/- 14.4 ng/mL; P = 0.001). Fasting serum calcium was lower in Cir than NCir patients, P = 0.019. Fasting intact PTH was elevated in 42% of the patients, but the mean serum levels were similar in Cir and NCir groups.

CONCLUSION

We found no evidence of vitamin D deficiency, but cannot exclude the participation of PTH in the high bone turnover and bone loss in the population with chronic viral hepatitis.

Vitamin D deficiency and secondary hyperparathyroidism in the elderly: consequences for bone loss and fractures and therapeutic implications

Vitamin D deficiency is common in the elderly, especially in the housebound and in geriatric patients. The establishment of strict diagnostic criteria is hampered by differences in assay methods for 25-hydroxyvitamin D. The synthesis of vitamin D3 in the skin under influence of UV light decreases with aging due to insufficient sunlight exposure, and a decreased functional capacity of the skin. The diet contains a minor part of the vitamin D requirement. Vitamin D deficiency in the elderly is less common in the United States than elsewhere due to the fortification of milk and use of supplements. Deficiency in vitamin D causes secondary hyperparathyroidism, high bone turnover, bone loss, mineralization defects, and hip and other fractures. Less certain consequences include myopathy and falls. A diet low in calcium may cause an increased turnover of vitamin D metabolites and thereby aggravate vitamin D deficiency. Prevention is feasible by UV light exposure, food fortification, and supplements. Vitamin D3 supplementation causes a decrease of the serum PTH concentration, a decrease of bone turnover, and an increase of bone mineral density. Vitamin D3 and calcium may decrease the incidence of hip and other peripheral fractures in nursing home residents. Vitamin D3 is recommended in housebound elderly, and it may be cost-effective in hip fracture prevention in selected risk groups.

Osteoporosis

Osteopenia, in the form of osteoporosis, is a common complication of chronic cholestatic liver diseases and, although its cause is poorly understood, it appears to be intimately related to the cholestasis itself. With more patients surviving longer with successful liver transplantation, the clinical significance of such osteopenia has increased, and a traumatic fracturing has become a major cause of morbidity in this patient population. Noninvasive diagnosis is easy, and serial measurements allow assessment of disease progression. Although no effective therapy can treat or prevent this complication, supportive measures can improve skeletal well-being, especially in high-risk individuals who are candidates for liver transplantation.

Amount and composition of bone minerals in chronic liver disease

Alterations in bone mineral are a common complication of chronic liver disease. The aim of the current study was to assess bone mineral status in patients with chronic liver disease not treated with corticosteroids and to investigate any possible correlation with the histological stage of liver disease. Bone mineral status in 27 patient with chronic active hepatitis, and 17 with active cirrhosis was compared to that of matched controls. Partial body neutron activation analysis was applied for measuring hand bone phosphorus, single-photon absorptiometry for measuring forearm bone mineral content, and dual-energy x-ray absorptiometry for measuring spinal bone mineral density. These noninvasive measurements were supplemented with data obtained by high resolution radiography and biochemistry. Decreased metacarpal cortical thickness was found in five patients, all in the cirrhotic group. In addition, both mean intact parathyroid hormone and 25-hydroxyvitamin D levels were reduced in this group of patients. The mean values of the quantities assessed by the in vivo techniques in patients in the early stages of the hepatic disease did not differ statistically from those of matched normal controls. On the contrary, these quantities were reduced by 9% in the patients at the late stages relative to controls. In conclusion, only the late stages of liver disease are associated with an increased risk of fractures.

Bone disease in cholestatic liver disease

Osteopenia in the form of osteoporosis is a common clinical problem associated with chronic cholestatic liver disease, and clinical morbidity from atraumatic fractures is increasing as more patients with PBC and PSC undergo successful liver transplantation. In the absence of symptomatic fractures, the clinical diagnosis may not be evident and must be sought by specific means to assess bone mineral density. The clinical problem has now been defined, but much remains unknown, from etiologic mechanisms to effective therapies. At present, it seems reasonable to provide aggressive supportive therapy in an attempt to maximize skeletal well-being until more effective therapies for osteopenia become available.

Vitamin D and osteocalcin levels in liver transplant recipients. Is osteocalcin a reliable marker of bone turnover in such cases?

Patients with advanced liver disease are at increased risk for the development of hepatic osteodystrophy in the form of either osteomalacia or osteoporosis. The pathogenesis of these two bone diseases is multifactorial and includes, among other factors, alterations in vitamin D metabolism, malnutrition and hypogonadism. Little is known regarding vitamin D metabolism and the osteoblastic activity in liver transplant recipients. In order to clarify these issues, vitamin D metabolites and osteocalcin levels were measured prior to and 30 days following liver transplantation in 30 cirrhotic patients of various etiologies. While the mean plasma concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D of the entire group of 30 patients were significantly greater prior to orthotopic liver transplantation (OLTx) as compared to those after OLTx (11.5 +/- 8.6 vs. 7.4 +/- 5.8 ng/ml, p = 0.0066 and 41.0 +/- 34.6 vs. 20.4 +/- 11.0 pg/ml, p = 0.0003, respectively), no significant changes in osteocalcin concentrations pre- or post-transplantation could be demonstrated (5.2 +/- 3.0 vs. 6.4 +/- 4.1 ng/ml, p = 0.51). Furthermore, no correlation between the plasma concentration of osteocalcin and either vitamin D metabolite, the prothrombin time or cyclosporine levels was found. The reasons for the normal levels of osteocalcin prior to OLTx can be explained by the fact that in vitamin-K-deficient states osteocalcin is predominantly decarboxylated and, therefore, a smaller proportion is bound to bone and/or the synthesis of osteocalcin is partially modulated by 1,25-dihydroxyvitamin D, the level of which has been found to be normal.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Aluminum and chronic renal failure: sources, absorption, transport, and toxicity

In normal subjects the gastrointestinal tract is a relatively impermeable barrier to aluminum with a low fractional absorption rate for this metal ion. Aluminum absorbed from the gastrointestinal tract is normally excreted by the kidneys; in the presence of impaired renal function aluminum is retained and accumulates in body tissues. Aluminum-containing medications are given, by mouth, to patients with chronic renal failure as phosphate-binding agents for the therapeutic control of hyperphosphatemia. Patients with chronic renal failure are also exposed to aluminum in domestic tap-water supplies used either for drinking or, in those on dialysis treatment, in the preparation of their dialysate. In patients with end-stage chronic renal failure, particularly in those on treatment by hemodialysis, the accumulation of aluminum in bone, brain, and other tissues is associated with toxic sequelae. An increased brain content of aluminum appears to be the major etiological factor in the development of a neurological syndrome called either "dialysis encephalopathy" or "dialysis dementia"; an increased bone content causes a specific form of osteomalacia. An excess of aluminum also appears to be an etiological factor in a microcytic, hypochromic anemia that occurs in some patients with chronic renal failure on long-term treatment with hemodialysis. The various mechanisms involved in the toxic phenomena associated with the accumulation of aluminum in body tissues have not been clearly defined but are the subject of extensive investigations.

Severe cholestasis leads to vitamin D depletion without perturbing its C-25 hydroxylation in the dog

The role of the liver as a contributory factor in the vitamin D deficiency of cholestatic liver disease has been studied in vivo in dogs with chronic bile duct ligation, whereas controls underwent diversion of the bile flow through the urinary bladder via a choledococystostomy anastomosis. The hepatic extraction of vitamin D3 was evaluated by the multiple indicator dilution technique, and the formation of 25-hydroxyvitamin D3 was assessed by directly sampling the hepatic effluent for up to 150 min after vitamin D3 administration. The serum and hemodynamic data indicate that dogs with chronic bile duct ligation had severe cholestasis and hepatocellular injury; histologically, macronodular cirrhosis was present. Dogs with choledococystostomy anastomosis had normal livers and normal liver function. The data indicate that the absence of normal bile flow into the intestinal lumen led to a progressive depletion of vitamin D reserve in both animals with choledococystostomy anastomosis and those with chronic bile duct ligation. However, neither the hepatic fractional extraction of vitamin D3, its hepatic clearance nor its transformation into 25-hydroxyvitamin D3 was significantly changed by chronic bile duct ligation. The results of the present studies indicate that the hepatic handling of vitamin D3 including its C-25 hydroxylation, is well preserved in the presence of severe cholestasis. They also suggest that the state of vitamin D depletion which often accompanies chronic cholestatic liver disease can largely be accounted for by factors such as secondary malabsorption of the vitamin due to the absence of adequate amounts of bile salts in the intestinal lumen, or by other factors which seem independent of the hepatic metabolism of vitamin D.

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.

Hyperparathyroidism, cirrhosis, and portacaval shunt. A new clinical syndrome

This is a report of six patients with cirrhosis of the liver in whom primary hyperparathyroidism occurred due to a solitary parathyroid adenoma 3 months to 9 years after undergoing emergency portacaval shunt for hemorrhage from esophageal varices. The presenting symptoms in all six patients were weakness and bone pain. Three patients had a bone fracture after insignificant trauma, one and probably two passed kidney stones, and a duodenal ulcer developed in two. Bone x-ray films showed generalized osteoporosis in all patients. Renal function and arterial blood pH were within normal limits in every patient. The diagnosis of primary hyperparathyroidism in each patient was based on repeated demonstrations of hypercalcemia, hypophosphatemia, and markedly elevated serum immunoreactive parathyroid hormone concentrations. In all six patients, removal of the parathyroid adenoma resulted in disappearance of symptoms; normalization of serum calcium, phosphorus, and immunoreactive parathyroid hormone levels; and in four of the six, improvement in radiographic evidence of osteoporosis during follow-up of from 1 to 6 years. The association of cirrhosis, portacaval shunt, and primary hyperparathyroidism has not been documented previously. Our six patients with primary hyperparathyroidism constitute 3.4 percent of 174 survivors of emergency portacaval shunt in a series of 264 unselected, consecutive patients with cirrhosis and bleeding esophageal varices. Hepatic osteodystrophy is known to have occurred in only 11 of these 174 survivors. Primary hyperparathyroidism may be a more common cause of hepatic osteodystrophy than has been previously recognized, and should be considered in patients with cirrhosis in whom weakness, bone pain, and bone demineralization develop, particularly if they have a portacaval anastomosis.

Vitamin D and mineral metabolism in intrahepatic cholestasis of pregnancy

Serum concentrations of 25(OH)D, 24,25(OH)2D, 1,25(OH)2D, total protein, calcium, phosphorus, magnesium and alkaline phosphatase were measured in patients with intrahepatic cholestasis of pregnancy and in control subjects at the third trimester of pregnancy and at delivery. 25(OH)D levels of 40.5 +/- 21.5 nmol/l in the patient group were initially significantly (P less than 0.01) higher than the value of 26.3 +/- 9.5 nmol/l in the control group and decreased significantly (P less than 0.01) to 26.0 +/- 16.3 nmol/l at delivery. The levels of active 1,25(OH)2D and inactive 24,25(OH)2D did not alter in either group. Also the concentrations of calcium, phosphorus and magnesium remained unchanged in both groups. No significant differences in fetal vitamin D metabolites were observed between patients and controls, and the other analysed fetal parameters were similar in both groups. Cholestyramine and/or phenobarbital treatment had no influence on vitamin D metabolites. Since levels of 1,25(OH)2D and mineral parameters remained normal and a change in 25(OH)D concentrations was only transient, the clinical role of 25(OH)D variations cannot be substantial.

Bone disease in primary biliary cirrhosis: increased bone resorption and turnover in the absence of osteoporosis or osteomalacia

The role of vitamin D in hepatic osteodystrophy was examined. Eleven unselected patients with primary biliary cirrhosis (PBC) were assessed for disorders of mineral and vitamin D metabolism. Six were not receiving supplementary vitamin D, and five were being treated with oral vitamin D (50,000 IU daily). Serum levels of 25-hydroxyvitamin D were normal in all patients receiving oral therapy and in 4 of 6 untreated patients. Levels of serum 1,25-dihydroxyvitamin D and 24,25-dihydroxyvitamin D were normal or near normal in all patients. Studies were repeated after 6 months of therapy with parenteral vitamin D2 (100,000 IU i.m. monthly) in 7 patients. Initial bone histomorphometry revealed no evidence of osteomalacia or osteoporosis. However, the bone resorption surface of trabecular bone was increased. This abnormality was no longer present on repeat bone biopsies obtained after parenteral vitamin D therapy, and bone formation had decreased. In addition, trabecular bone volume remained normal in the face of the lower rate of bone formation. Increased bone resorption surface in the absence of osteoporosis or osteomalacia has not been previously described in PBC. Improvement in this bone parameter, associated with the finding of a decrease in the formation of bone and in hydroxyproline excretion in urine after parenteral vitamin D, suggests that increased turnover may be an early feature of the bone disease which complicates PBC and that parenteral vitamin D may retard the rate at which hepatic osteodystrophy develops in chronic cholestatic liver disease.

Comparison of vitamin E and 25-hydroxyvitamin D absorption during childhood cholestasis

To characterize differences in intestinal absorption of fat-soluble vitamins during cholestasis, intestinal absorption of vitamin E was compared with that of 25-hydroxyvitamin D in eight infants and young children with prolonged neonatal cholestasis. Oral tolerance tests were performed using 100 IU/kg/dose dl-alpha-tocopherol and 10 micrograms/kg/dose 25-hydroxyvitamin D. Mean vitamin E absorption was only 1.0% to 1.9% of that of control children, whereas 25-hydroxyvitamin D absorption was 22.5% to 25.1% of that of controls. Although intestinal absorption of both vitamins is impaired during cholestasis, the severity of vitamin E malabsorption far exceeds that of 25-hydroxyvitamin D.

Hepatic osteodystrophy in primary biliary cirrhosis: a possible defect in Kupffer cell mediated cleavage of parathyroid hormone

Twelve of fourteen female patients with primary biliary cirrhosis, receiving vitamin D supplementation, exhibited unequivocal signs of osteoporosis but not of osteomalacia. Vitamin D treatment reproduced normal 25-hydroxyvitamin D levels in all but two patients and the 1,25 and 24,25-dihydroxyvitamin D metabolic pathways appeared to be unimpaired. A possible mechanism for the vitamin D resistant osteoporosis has been identified following the observation that, in those patients with severe cirrhosis, the circulating concentration of intact PTH was elevated. The increase in intact hormone appears to be at the expense of the carboxyl-regional PTH produced by hepatic Kupffer cell mediated cleavage of intact PTH. As a defect in Kupffer cell function is documented in primary biliary cirrhosis we postulate that the increased intact PTH/decreased carboxyl-regional PTH concentrations arise as a result of diminished Kupffer cell mediated cleavage. The reduced generation of cleaved PTH, due to this loss of Kupffer cell activity, would thus contribute to the development of osteoporosis in primary biliary cirrhosis.

Unusual sialilation of the serum DBP associated with the Gc 1 allele in alcoholic cirrhosis of the liver

The serum level of the 'vitamin D binding protein' (DBP) or Gc ('group-specific component'), its phenotype distribution and the quantitative estimation of the different electrophoretic isoforms were determined in a sample of healthy individuals (blood donors) and in patients with alcoholic hepatitis. It is shown that the serum DBP levels and the amount of the different electrophoretic isoforms are influenced by the protein phenotypes. In the patients an increased frequency of the Gc 1 allele is noticed. For the first time, an unusual form of the apo DBP protein was detected but only in the sera of the Gc 1 allele carriers. The protein form investigated by analytical procedures presents one more sialic acid residue than the usual Gc 1 protein. This unusual metabolic transformation of the DBP is mostly observed among male patients and is often associated with a deteriorating clinical outcome.

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.

Intestinal absorption and 25-hydroxylation of vitamin D in patients with primary biliary cirrhosis

The absorption, metabolism, and excretion of vitamin D3 was studied in eight women with an established diagnosis of primary biliary cirrhosis (PBC), and the results were compared with those obtained from eight healthy women of a similar age. Four patients had hyperbilirubinemia, low serum calcium levels, and a reduced mineral content of the bone, whereas the other four were presymptomatic with respect to bone disease. Vitamin D absorption was studied after oral administration of tritiated vitamin D, and the appearance of serum radioactivity was recorded. After this, the liver 25-hydroxylation of vitamin D was studied by administering an intravenous dose of tritiated vitamin D and then chromatographing serum samples to determine the radioactivity of the 25-OH D fraction. All PBC patients had normal 25-hydroxylation capacity of the vitamin, and there was no difference in the urinary excretion of radioactivity. On the other hand, the intestinal absorption of vitamin D was severely impaired both in the symptomatic and asymptomatic patients. The absorption of the vitamin was negatively correlated to the amount of fecal fat, and the results suggest that low serum levels of 25-OH D in symptomatic PBC seem to be caused by the steatorrhea, whereas hepatic conversion of vitamin D into 25-OH D seems to be well preserved even in patients with hyperbilirubinemia and signs of osteomalacia. The absorption-metabolism test may be a valuable tool in the study of patients with cholestatic liver disease for determining the nature of the vitamin D deficiency and the logical form of substitution therapy.

Hepatic vitamin D 25-hydroxylase: inhibition by bile duct ligation or bile salts

Bone disease and low serum levels of 25-hydroxyvitamin D are prevalent in cholestatic syndromes such as primary biliary cirrhosis and biliary atresia. Defective hydroxylation, along with malabsorption of vitamin D, could be a factor in 25-hydroxyvitamin D depletion. To assess hepatic hydroxylation during experimental cholestasis, we studied vitamin D 25-hydroxylase activity in liver homogenates of rats after 7, 14, and 21 days of bile duct ligation. We have also studied the effects of bile acids on this enzyme in vitro. Hepatic 25-hydroxylation was depressed after 7 days ligation in only 1 of 4 animals, but by 14 days, all animals showed a marked reduction with a mean decrease of 64% in specific activity. Total liver enzyme activity was reduced by 43% at 14 days. In the ligated animals, liver histology showed progressive bile stasis, focal necrosis, bile ductular proliferation, periductular and periportal inflammation, and fibrosis. Addition of bile acids to the in vitro assay in concentrations approximating those found in cholestasis produced marked inhibition of vitamin D 25-hydroxylase activity.

Vitamin D prophylaxis and osteomalacia in chronic cholestatic liver disease

Bone histology was examined in 32 patients with chronic cholestatic liver disease, of whom just over one half were receiving high-dose parenteral vitamin D therapy. Four patients had histological evidence of osteomalacia; two of these were receiving vitamin D therapy, and showed only very mild osteomalacia, while the remaining two untreated patients had more severe bone disease. Plasma 25-hydroxyvitamin D levels were normal in all vitamin D-treated patients, and serum calcium concentrations were significantly higher in the treated group. Clinical symptoms and biochemical and radiological findings were unreliable in predicting osteomalacia. It is concluded that osteomalacia is uncommon in patients with chronic cholestatic liver disease irrespective of whether or not they are receiving vitamin D therapy. However, high-dose parenteral vitamin D prophylaxis protects against vitamin D deficiency and may also prevent the development of severe bone disease.

Perspective in liver disease: An Irish experience

CONCLUSIONS

Graves travelled extensively and on one trip to Italy in 1819 he was joined by a man he describes as of rough exterior and being more "like a ship's mate" (Widdess, 1963). This man sketched extensively and was in fact the famous English painter - J. M. W. Turner. Graves, who was also sketching, was under no illusion as to who was the master and remarked later to Stokes - "When we compared drawings, the effect was strange. Not a single stroke in Turner's drawing was like nature … and yet my work was worthless in comparison to his. The whole glory of the scene was there". Graves acknowledged Turner's mastery in the field of sketching. No one can deny that this extra-ordinary man, with his clinical observations, deserves his eminent place in Irish medicine. Indeed continued studies of his writings can still prove beneficial to the present day scholar.

Plasma vitamin D-binding globulin in vitamin D deficiency, pregnancy and chronic liver disease

Plasma concentrations of vitamin D-binding globulin were measured by radial immunodiffusion in healthy subjects, pregnancy, and during oestrogen therapy. Subjects with disorders of vitamin D metabolism (dietary deficiency, malabsorption, anticonvulsant therapy, chronic liver disease) were also studied. Neither sex nor age influenced the plasma vitamin D-binding globulin concentration in healthy subjects, but there was a significant increase in concentration during pregnancy and oestrogen therapy. Elevated levels were found in vitamin D deficient elderly but not younger subjects, while levels in subjects with chronic liver disease were significantly reduced. Normal levels of vitamin D-binding globulin were present in hypervitaminosis D and no vitamin D-binding globulin was detected in human milk. No correlation was observed between plasma 25-hydroxycholecalciferol levels and plasma vitamin D-binding globulin concentrations.

Phosphate metabolism in chronic liver disease

Phosphate metabolism was investigated in 26 patients with a spectrum of liver diseases and mean fasting plasma phosphate concentrations were in the low normal range. A standard oral load of phosphate was used to test absorption and was subnormal in the majority of patients with large bile-duct obstruction and alcoholic liver disease. Subnormal results were also seen in patients with primary biliary cirrhosis and cirrhosis secondary to chronic active hepatitis. These abnormalities appeared to be related to vitamin-D deficiency. Tubular reabsorption of phosohate was markedly reduced in 3 of 14 patients. The therapeutic implications of phosphate status in liver disease are important.

Formation of vitamin D metabolites from 3H- and 14C-radiolabelled vitamin D-3 in chronic liver diseases

Four of the eight patients studied were vitamin D replete and 4 vitamin D depleted as judged by serum 25-hydroxy vitamin D (25-OHD) concentration. Three of the 4 vitamin D depleted patients (including 2 with histological osteomalacia) formed radioactive 1,25-dihydroxycholecalciferol. One of the four vitamin D replete patients formed 1,25-dihydroxycholecalciferol but all formed 24,25-dihydroxycholecalciferol. This study suggests that patients with liver disease form dihydroxy vitamin D metabolites in an appropriate manner.

Serum 25-hydroxyvitamin D levels in thalassaemia

Serum 25-hydroxyvitamin D levels were measured in 36 thalassaemic children and 27 controls aged 5-15 years. Blood specimens were collected from the beginning of April until the end of October 1976. We considered as the winter period the first 3 months and the summer period the last 4 months. We found that (a) thalassaemic children had lower levels of serum 25-hydroxyvitamin D than controls: (b) there was a seasonal variation of serum 25-hydroxyvitamin D in both groups; and (c) the thalassaemic children had malabsorption of vitamin D. We suggest that the bone lesions in thalassaemic children are related to vitamin D deficiency.

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.