The hepatic conversion of vitamin D in alcoholics with varying degrees of liver affection

Micro-ribonucleic acids: potential noninvasive biomarkers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies globally. Each year, more than 500,000 people worldwide are diagnosed with HCC. The onset of HCC is typically unnoticeable, and the prognosis is usually poor. The early diagnosis of HCC and dynamic monitoring of this disease can contribute to more effective therapeutic interventions and improve patient outcomes. To achieve early diagnosis, more sensitive, specific, and easily detectable biomarkers are necessary. Recently, scientists have focused on identifying novel, sensitive, and minimally invasive or noninvasive biomarkers. Micro-ribonucleic acids (miRNAs) are a class of endogenous noncoding single-stranded RNAs that regulate gene expression at the posttranscriptional level. By negatively regulating target-gene expression, miRNAs play a critical role in diverse biological processes, including apoptosis, proliferation, differentiation, and developmental timing. Unique changes in miRNA expression in serum or plasma samples from HCC patients have been reported, suggesting that miRNAs may serve as novel noninvasive biomarkers for diagnosing HCC and evaluating therapeutic responses or as potential therapeutic targets in HCC. This review focuses on recent progress in understanding the role of miRNAs in HCC pathogenesis and progression, and highlights their diagnostic and prognostic value for HCC patients.

Impairment of vitamin D and bone metabolism in patients with bypass operation for obesity

Thirty-four patients were studied 2--6 years after jejunoileal bypass for morbid obesity. The serum concentration of 25-hydroxyvitamin D (25-OHD) were reduced and related to the frequency fo stools and to the weight reduction. Fifteen patients were not able to normalize serum 25-OHD following a long-term regular vitamin D intake. The serum immunoreactive parathyroid hormone concentration (iPTH) and the alkaline phosphatase levels were elevated in this group, indicating a secondary hyperparathyroidism. The mean bone mineral content of the forearm was reduced 3--6 years after the operation, most severely in those with elevated serum iPTH. The desired weight reduction by jejunoileal shunt was obtained at the expense of a severely disturbed vitamin D metabolism. We suggest, that all patients with an intestinal bypass for obesity should receive regular vitamin D supplement, and serum 25-OHD should be measured in order to monitor the effect of therapy.

Chronic ethanol consumption leads to disruption of vitamin D3 homeostasis associated with induction of renal 1,25 dihydroxyvitamin D3-24-hydroxylase (CYP24A1)

Bone loss resulting from chronic ethanol (EtOH) abuse is frequently accompanied by altered vitamin D3 homeostasis. In the current study, we examined EtOH effects in a female rat model in which control or EtOH-containing diets were infused intragastrically. EtOH treatment reduced plasma 1,25-dihydroxycholecalciferol (1,25 (OH)2 D3) coincident with a decrease in renal CYP27B1 (25(OH)D3 1alpha-hydroxylase) mRNA and an increase in expression of renal CYP24A1 (1,25 (OH)2 D3- 24-hydroxylase). EtOH induction of CYP24A1 occurred as a result of increased transcription and was also observed in vitro in primary cultures of rat renal proximal tubule cells (RPTCs) and in NRK-52E cells. Synergistic induction of CYP24A1 by EtOH in combination with 1,25 (OH)2 D3 was observed. The major EtOH metabolizing enzymes, alcohol dehydrogenase-1 and CYP2E1, were induced by EtOH in RPTCs. Inhibition of EtOH metabolism by 4-methylpyrazole inhibited the induction of CYP24A1 mRNA. CYP24A1 mRNA induction in RPTCs was also inhibited by the protein synthesis inhibitor cycloheximide. CYP24A1 was also induced after hydrogen peroxide treatment, and EtOH treatment of RPTCs resulted in production of reactive oxygen species as measured by flow cytometry using the fluorescent probe dichlorofluorescin acetate. In addition, inhibition of MAPK signaling pathways with the MAPK kinase inhibitor U0126 or the p38 inhibitor SB203580 inhibited EtOH induction of CYP24A1. Our data suggest that EtOH reduces circulating 1,25 (OH)2 D3 concentrations as the result of CYP24A1 induction that is mediated via MAPK activation resulting from renal oxidative stress produced by local metabolism of EtOH via CYP2E1 and antidiuretic hormone-1.

Alcohol, osteoporosis, and bone regulating hormones

The mechanism of the production of ethanol-associated osteopenia seems to be a direct effect of alcohol on bone cells and an indirect or modulating effect through mineral regulating hormones such as vitamin D metabolites, parathyroid hormone, and calcitonin. The modulating effects of these hormones on bone and mineral metabolism in acute and chronic alcohol consumption is discussed herein.

Bone and the 'comforts of life'

Coffee drinking, smoking and especially alcohol abuse are considered to be risk factors for fractures and osteoporosis. Caffeine causes acute increase in urinary calcium excretion, but epidemiological evidence for the effects of coffee consumption on the risk of fractures is contradictory. Many, (but not all) studies point to decreased bone mass or increased fracture risk in smokers. Alcohol abuse is associated with deleterious changes in bone structure detected by histomorphometry, and with a decrease in bone mineral density (BMD). These changes may also be produced by factors commonly associated with alcohol abuse, e.g. nutritional deficiencies, liver damage and hypogonadism. Alcohol, however, has clear-cut direct effects on bone and mineral metabolism. Acute alcohol intoxication causes transitory hypoparathyroidism with resultant hypocalcaemia and hypercalciuria. As assessed by serum osteocalcin levels, prolonged moderate drinking decreases the function of osteoblasts, the bone-forming cells. In addition, chronic alcoholics are characterized by low serum levels of vitamin D metabolites. Thus, alcohol seems to have a direct toxic effect on bone and mineral metabolism. In contrast, it has recently been reported that moderate alcohol consumption by postmenopausal women may have a beneficial effect on bone.

Alcoholism-associated spinal and femoral bone loss in abstinent male alcoholics, as measured by dual X-ray absorptiometry

Although alcoholism is a known risk factor for osteoporosis, there are few published reports on alcoholism-associated bone loss. To study alcoholism-associated bone loss, this study used a dual X-ray absorptiometry (DXA) densitometer to measure lumbar and femoral bone mineral density (BMD) in a previously little-studied population: 32 relatively healthy, nonhospitalized, Caucasian, alcoholic men with a period of abstinence longer than that previously studied (median abstinence 4.0 months, range 3 days-36 months). DXA is a new, highly precise densitometric method with many advantages over the methods used in previous studies. The subjects had statistically significant bone loss at three sites: lumbar spine, femoral neck, and Ward's triangle (multiple correction adjusted two-tailed P < 0.008). Compared to the mean BMD of sex-, age-, and race-matched norms, the subjects' average femoral neck, Ward's triangle, and lumbar BMDs were, respectively, 0.56, 0.69, and 0.57 standard deviations (SDs) below the normative values.

Effects of 3 weeks' moderate alcohol intake on bone and mineral metabolism in normal men

To study the effects of prolonged moderate alcohol intake on bone and mineral metabolism, 60 g/day of ethanol was administered to 10 healthy male volunteers during 3 weeks. The drinking period was preceded and followed by an abstinence period of 3 weeks. The serum level of osteocalcin decreased by 30% towards the end of the alcohol period (P less than 0.01), recovering by 25% after the termination of drinking (P less than 0.01). The serum level of intact parathyroid hormone increased to the end of the drinking period (P less than 0.05). After stopping drinking it came back to baseline (P less than 0.05) within a week. The serum levels of 25(OH)D3, 1,25(OH)2D3, 24,25(OH)2D3, the serum and urinary levels of calcium, and the intestinal absorption of calcium measured by stable strontium remained practically unchanged throughout the whole observation period. We conclude that prolonged moderate alcohol intake impairs osteoblastic function, leading to lowered serum levels of osteocalcin, but it does not derange vitamin D metabolism.

Transient hypoparathyroidism during acute alcohol intoxication

BACKGROUND

Persons with chronic alcoholism frequently have hypocalcemia, hypomagnesemia, and osteoporosis. The short-term effects of alcohol ingestion on calcium and magnesium metabolism are poorly understood, however.

METHODS

We measured serum calcium, magnesium, and phosphate concentrations in 17 normal men and 7 normal women before and at intervals up to 16 hours after the ingestion of 1.2 to 1.5 g of alcohol per kilogram of body weight over a 3-hour period (doses sufficient to cause acute intoxication). Urinary excretion of calcium, magnesium, and phosphate and serum calciotropic hormone levels were measured in 16 of these subjects. As a control, the same measurements were made after the ingestion of fruit juice instead of alcohol.

RESULTS

The mean (+/- SE) peak blood alcohol level in the men was 37.5 +/- 1.6 mmol per liter, and in the women it was 38.0 +/- 3.2 mmol per liter. In the men the mean serum parathyroid hormone concentration decreased from 16.1 +/- 2.1 to 6.8 +/- 0.9 ng per liter at the end of the three-hour drinking period. The value at this time was 30 percent of that at the end of the three-hour session during which the men drank fruit juice (P = 0.004). The serum concentration of ionized calcium reached a nadir eight hours after the beginning of alcohol administration (decreasing from 1.18 +/- 0.01 to 1.15 +/- 0.01 mmol per liter; P less than 0.001 as compared with values during the fruit-juice study), and urinary excretion of calcium increased from 0.34 +/- 0.08 to 0.36 +/- 0.08 mmol per hour (P less than 0.01 as compared with values during the fruit-juice study). Serum parathyroid hormone levels exceeded base-line values during the last 4 hours of the 16-hour study period; this increase was accompanied by a decrease in the urinary excretion of calcium. Both serum levels of magnesium (in the first 6 hours) and urinary levels (in the first 12 hours) increased after the ingestion of alcohol. In the women, serum parathyroid hormone levels decreased from 29.2 +/- 2.8 to 17.3 +/- 2.6 ng per liter two hours after the administration of alcohol was begun (P less than 0.001) and increased above base-line values during the last four hours of the study period. The serum concentration of ionized calcium decreased from 1.20 +/- 0.01 to 1.16 +/- 0.01 mmol per liter, reaching a nadir 8 to 12 hours after alcohol administration was begun (P less than 0.001).

CONCLUSIONS

Short-term alcohol administration causes transitory hypoparathyroidism. This decline in the secretion of parathyroid hormone accounts at least in part for the transient hypocalcemia, hypercalciuria, and hypermagnesuria that follow alcohol ingestion.

In micronodular cirrhosis, hepatocytes retain a normal C-25 hydroxylation capacity toward vitamin D3: a study using the rat carbon tetrachloride-induced cirrhotic model

To test further the competence of the cirrhotic liver to metabolize vitamin D3 at C-25, hepatocytes were isolated from controls and from CCl4-induced cirrhotic rat livers, as well as from partially hepatectomized rats. The transformation of D3 into 25-hydroxyvitamin D3 was studied in the presence of 10(7) hepatocytes at D3 concentrations of 20 nmol/L to 15.4 mumol/L. Histologically, micronodular cirrhosis was present in all CCl4-treated rats, whereas controls had normal livers; portal venous pressure (p less than 0.008) and intrahepatic collagen content (p less than 0.0001) were significantly increased in CCl4-treated rats, whereas no difference was found between the two groups in the total and ionized serum calcium, D3 metabolites, ALT, AST and alkaline phosphatase. Cytochrome P-450 was 0.27 +/- 0.02 and 0.25 +/- 0.02 nmol/10(6) hepatocytes in controls and cirrhotic rats (N.S.), and it significantly increased in both groups after phenobarbital or 3-methylcholanthrene administration (p less than 0.0001). 25-Hydroxyvitamin D3 formation was best described by power law equations and varied between 0.02 +/- 0.0004 and 29.57 +/- 2.8 in controls, and 0.024 +/- 0.0004 and 32.0 +/- 7.0 pmol.hr-1.10(6) hepatocytes-1 in cirrhotic rats. No statistically significant difference was found in the slopes of the 25-hydroxyvitamin D3 formation, but the y-axis intercept was found to be lower in cirrhotic rats under basal resting conditions (p less than 0.005). Inducers of the mixed function oxidases significantly increased 25-hydroxyvitamin D3 formation in controls as well as in cirrhotic rats (p less than 0.005). Moreover, both groups were found to respond similarly to the addition of modulators of the enzyme such as the calcium ionophore A23187 and parathyroid hormone. Partial hepatectomy was also without effect on the activation of D3. Furthermore, the cell sequestration of D3 was also found to be unperturbed in hepatocytes obtained from either cirrhotic or partially hepatectomized livers. The data indicate that in well-compensated micronodular cirrhosis, the C-25 hydroxylation of D3 is generally intrinsically normal at the cellular level and that it also remains fully responsive to in vivo and in vitro modulators of its activity.

Abnormal vitamin D3 metabolism in patients with primary Sjögren's syndrome

Recent studies have suggested that vitamin D3 may have an immunoregulatory role in vitro. The vitamin D3 metabolism in 35 patients with primary Sjögren's syndrome was investigated by measuring blood concentrations of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-(OH)2D3) and 25-hydroxyvitamin D3 (25-OHD3), as well as phenotypes and blood concentrations of Gc globulin, the main vitamin D3 binding protein in the blood. 25-OHD3 concentrations were diminished, but those of 1 alpha,25-(OH)2D3 were normal. There was no significant difference between the distribution of Gc phenotypes in the patients with primary Sjögren's syndrome and normal controls. Likewise, blood concentrations of Gc globulin corresponded to normal values. Among patients with increased concentrations of IgM rheumatoid factor there was a significant negative correlation between the serum titres of IgM rheumatoid factor and 25-OHD3 concentrations.

Deranged vitamin D metabolism but normal bone mineral density in Finnish noncirrhotic male alcoholics

To study the effect of prolonged ethanol consumption on calcium metabolism and on the prevalence of osteoporosis we examined 38 Finnish noncirrhotic male alcoholics (30-55 years of age) with dietary interviews and biochemical measurements and by measuring the bone mineral content of the forearm using single photon absorptiometry (SPA) and the bone mineral density of the spine, humerus and proximal femur using nonquantified computer tomography (CT) and dual-energy x-ray absorptiometry (DEXA). In comparison two groups of healthy controls were studied. The mean daily dietary intake of calcium was 1.3 g in the patients and 1.2 g in the controls. The dietary intake of vitamin D was equal in the study groups, too. The serum levels of calcium, phosphate and parathyroid hormone did not show any difference between the patients and controls but in the alcoholics the urinary excretion of calcium was reduced by 42% (p less than 0.0001) as compared to the controls. The serum levels of 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, and 24,25-dihydroxyvitamin D3 were reduced in the alcoholics by 40% (p less than 0.0001), 23% (p less than 0.01), and 48% (p less than 0.0001), respectively, as compared to the controls. The alcoholic men had normal levels of serum testosterone and they did not have hypercortisolism. The bone mineral content of the dominant forearm measured by SPA was similar in the study groups as were the bone mineral densities (BMD) of the lumbar and humeral areas measured by CT. The BMD at the lumbar, femoral neck, Ward's triangle and trochanter sites measured by DEXA did not differ, either.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone changes in alcoholic liver cirrhosis. A histomorphometrical analysis of 52 cases

Bone biopsies of 52 histologically confirmed alcoholic cirrhotic patients and 15 age- and sex-matched controls have been histomorphometrically analyzed determining trabecular bone volume (TBV), mineralized bone volume (MBV), and osteoid volume (OV). We also determined serum PTH, 25-OH-D3, calcitonin, FSH, LH, estradiol, testosterone, T3 and T4, urine cortisol, routine liver function tests, serum and urinary calcium, phosphorus, and magnesium. We found a high prevalence of osteoporosis: TBV was significantly lower in cirrhotic patients (T = 7.23, P less than 0.001), 41 of them being in the range of osteoporosis; none of them had osteomalacia. Levels of all the above-mentioned hormones and electrolytes were almost normal, and no correlation was found between them and liver function tests, as occurred with the bone parameters.

Hepatic handling of vitamin D3 in micronodular cirrhosis: a structure-function study in the rat

The response to vitamin D3 (D3) was studied in a model of micronodular cirrhosis induced by CCl4. The uptake and C-25 hydroxylation of D3 were then studied in isolated-perfused liver preparations. CCl4-treated rats had a significantly lower fractional hepatic D3 uptake than controls; they also had lower 25-hydroxyvitamin D3 (25(OH)D3) concentrations in both liver and perfusate following 150 min of perfusion. CCl4 induced a wide spectrum of hepatic morphologic changes ranging from mild to large collagen infiltration, but micronodular cirrhosis was present in more than 90% of the animals. Histomorphometric analysis of the liver indicated an overall highly significant increase in the volume density (Vv) of collagen infiltration, and a reduction in the Vv normal hepatocytes following CCl4. Linear relationships were also observed between the Vv normal hepatocytes and the liver, perfusate, and total 25(OH)D3, while the 25(OH)D3 production decreased in a logarithmic fashion as the collagen infiltration of the liver parenchyma increased. These data show that the overall production of 25(OH)D3 is decreased in micronodular cirrhosis; they also indicate, however, that the D3-25 hydroxylase seems to stay unimpaired in the remaining hepatocytes of the diseased liver, and that the Vv normal hepatocytes constitute one of the major determinants of the 25(OH)D3 production by the cirrhotic rat liver.

Calcium status and calcium-regulating hormones in alcoholics

To elucidate effects of chronic ethanol consumption on clinical chemical parameters reflecting overall calcium homeostasis 34 hospitalized male alcoholics and 35 age-matched controls were studied during the winter season. Serum concentrations of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 were reduced by 28% (p less than 0.01) and 24% (p less than 0.02) among the alcoholics as compared to the controls, respectively. Dietary intake of vitamin D3 did not differ significantly between the groups. The calcium level was below lower limit of reference in nine alcoholics (26%). Serum concentrations of parathyroid hormone and phosphorus were within normal ranges in both groups, and no differences were observed in levels of magnesium, vitamin D-binding protein, calcitonin, or alkaline phosphatase. In conclusion, it is possible that the activities of enzymes crucial in vitamin D3 metabolism may be altered in alcoholics.

Free 25-hydroxyvitamin D levels are normal in subjects with liver disease and reduced total 25-hydroxyvitamin D levels

We determined the free fraction of 25-dihydroxyvitamin D (25OHD) in the serum of subjects with clinical evidence of liver disease and correlated these measurements to the levels of vitamin D binding protein and albumin. These subjects when compared to normal individuals had lower total 25OHD levels, higher percent free 25OHD levels, but equivalent free 25OHD levels. These subjects also had reduced vitamin D binding protein and albumin concentrations. The total concentration of 25OHD correlated positively with both vitamin D binding protein and albumin, whereas the percent free 25OHD correlated negatively with vitamin D binding protein and albumin. The free 25OHD levels did not correlate with either vitamin D binding protein or albumin. We conclude that total vitamin D metabolite measurements may be misleading in the evaluation of the vitamin D status of patients with liver disease, and recommend that free 25OHD levels also be determined before making a diagnosis of vitamin D deficiency.

Disorders of divalent ions and vitamin D metabolism in chronic alcoholism

This chapter reviews the pathogenesis of disordered divalent mineral and bone metabolism in alcoholism, emphasizing the role of impaired vitamin D physiology. Normally, vitamin D metabolites are derived principally from cholecalciferol, which is synthesized in the skin via the energy of sunlight. Most alcoholics have subnormal levels of 25-hydroxyvitamin D [25(OH)D]. Those with Laennec's cirrhosis also have low levels of vitamin D binding protein due to impaired hepatic protein synthesis and as a result, have low serum concentrations of total, but not free, 1,25-dihydroxyvitamin D. The causes of 25(OH)D deficiency in alcoholics include reduced hepatic 25-hydroxylase activity, lack of sun exposure, inadequate dietary intake, and malabsorption. Hypomagnesemia and hypophosphatemia, which are very common in hospitalized alcoholics, result from deficient intake, malabsorption, excessive renal losses, and cellular uptake of both ions. Hypocalcemia in alcoholics is caused primarily by hypoalbuminemia but can result also from deficient intake, malabsorption, hypomagnesemia, and renal calcium wastage. Low vitamin D activity may contribute significantly to the calcium and phosphate deficiencies. Osteoporosis is extremely common in alcoholics whereas osteomalacia is exceptional. However, both bone disorders respond well to vitamin D therapy. Thus, alcoholics should be screened periodically for vitamin D deficiency and osteopenia, and when either is detected they should receive vitamin D supplements.

Low serum 25-hydroxyvitamin D in hereditary hemochromatosis: relation to iron status

Under normal conditions, vitamin D absorbed from the diet or synthesized in the skin is transported to the liver where it undergoes hydroxylation. The purpose of this study was to determine whether excess hepatic iron affects this process and the subsequent production of 1,25-dihydroxyvitamin D (1,25-[OH]2D) in the kidney. Mean serum 25-hydroxyvitamin D (25-OHD) concentrations in untreated hereditary hemochromatosis were 13 +/- 6 (SD) in 9 patients with cirrhosis, 13 +/- 6 in 5 patients with hepatic fibrosis, and 22 +/- 6 in 10 patients with normal hepatic architecture aside from siderosis and were significantly lower than the levels found in 24 controls matched for age, sex, and season, p less than 0.05. The mean serum 25-OHD levels in the two groups with hemochromatosis and hepatic damage were significantly lower than the value in the group with normal hepatic architecture, p less than 0.05. Serum 25-OHD levels in individual patients were inversely related to the size of body iron stores as measured by exchangeable body iron, r = -0.64, or serum ferritin, r = -0.47, p less than 0.05. In 15 patients removal of excess body iron by venesection therapy produced a significant increase in the mean serum 25-OHD from 20 ng/ml to 30 ng/ml, p less than 0.05. In contrast, mean serum 1,25-[OH]2D levels were similar in iron-loaded and control subjects, indicating that the regulation of this metabolite was intact in patients with hemochromatosis. The results reveal that the low serum 25-OHD concentration in patients with hemochromatosis is directly related to the extent of iron loading and it is improved by venesection therapy.

Metabolic bone disease in alcoholic cirrhosis: a comparison of the effect of vitamin D2, 25-hydroxyvitamin D, or supportive treatment

In a study of 56 alcoholics with liver cirrhosis, 18 (32%) had decreased bone density and low levels of serum 25-hydroxyvitamin D (25-OH-D) (less than 20 ng per ml). To compare the efficacy of vitamin D2 and 25-OH-D treatment in correcting the metabolic bone disease in alcoholic cirrhosis, the 18 patients were randomized in the following manner, in groups of six patients each: Group 1, control (received no supplemental vitamin D treatment); Group 2, given vitamin D2 (50,000 IU p.o.) two to three times weekly, and Group 3, treated with 25-OH-D (20 to 50 mg p.o.) daily as required to attain normal serum 25-OH-D levels. The study period lasted 6 to 12 months (mean, 10.7 months). Initial histomorphometric study of transiliac bone biopsy with double tetracycline labeling in nine patients in whom biopsy was feasible showed only osteoporosis without evidence of osteomalacia. By the end of the study, serum 25-OH-D levels in the control group (Group 1) raised slightly while showing marked improvement in Groups 2 and 3. Bone density results remained unchanged in control patients but demonstrated a significant increase in both treatment groups. Vitamin D2 and 25-OH-D were equally effective in increasing bone density measurements. Posttreatment biopsies were performed in three patients of Group 2 and two patients of Group 3. While the histomorphometric results in Group 3 were not conclusive, in Group 2 improvement in static measures of bone remodeling was noted. Osteoporosis is the usual form of bone disease in alcoholic cirrhosis and a response to either vitamin D2 or 25-OH-D treatment is suggested.

Phosphorus administration in patients with profound hypophosphatemia

The influence of severe hypophosphatemia (less than or equal to 1.0 mg/dl) on vitamin D metabolism was prospectively determined in 11 patients before and after intravenous phosphorus administration. Evidence of liver dysfunction was present in ten patients. The mean (+/- SE) plasma 25 hydroxycholecalciferol [25(OH)D] was significantly decreased before phosphorus therapy when compared to control subjects (9.4 +/- 1.3 vs. 17.8 +/- 1.3 ng/ml, P less than 0.001). With phosphorus administration, serum phosphorus increased from 0.59 +/- 0.07 to 2.58 +/- 0.09 mg/dl while 1,25 dihydroxycholecalciferol [1,25(OH)2D] decreased from 34.6 +/- 4.3 to 14.3 +/- 2.9 pg/ml (P less than 0.001). Plasma 25(OH)D, plasma immunoreactive PTH (both amino and carboxyterminal) and serum calcium did not change after phosphorus administration, suggesting that phosphorus alone was responsible for the change in plasma 1,25(OH)2D concentration. An inverse correlation was found between serum phosphorus and plasma 1,25(OH)2D (r = -0.62, P less than 0.005). In addition, a direct correlation was observed between plasma 25(OH)D and 1,25(OH)2D both before (r = 0.66, P less than 0.005) and after (r = 0.74, P less than 0.005) phosphorus administration. Thus, the decrease in 1,25(OH)2D levels with phosphorus therapy suggests a role of serum phosphate in the regulation of this sterol, and hypophosphatemia or phosphorus depletion may change the relationship of substrate [25(OH)D] to product [1,25(OH)2D].

Evidence for secondary hyperparathyroidism in the osteomalacia associated with chronic liver disease

Previous reports have suggested that secondary hyperparathyroidism is extremely uncommon in hepatic osteomalacia. This, together with other findings, has led to suggestions that in chronic liver disease there may be selective resistance of bone to vitamin D or a specific bone mineralization defect unrelated to Vitamin D. To examine these possibilities, twenty-five patients with chronic liver disease have been studied by bone biopsy, serum calcium and inorganic phosphate, plasma 25-hydroxyvitamin D, plasma immunoreactive parathormone (iPTH), fasting urine cAMP, fasting renal tubular maximal reabsorptive capacity for phosphate (TmP/GFR) and fine grain hand x-rays. Nine of the patients had osteomalacia on bone biopsy, eight of these had subnormal levels of plasma 25-hydroxyvitamin D and the other had a borderline result. Based on the consensus of all the tests, five of these had evidence of secondary hyperparathyroidism. Plasma iPTH was higher in patients with osteomalacia than in patients without osteomalacia (P less than 0.01) or controls (P less than 0.01). Urine cAMP was higher in patients with osteomalacia than in patients without osteomalacia (P less than 0.001) or controls (P less than 0.01). TmP/GFR was significantly lower in patients with osteomalacia than in controls (P less than 0.05) but not significantly different from patients without osteomalacia. The findings of this study indicate that hyperparathyroidism occurs in a substantial proportion of patients with the osteomalacia of chronic liver disease. Moreover, osteomalacia in chronic liver disease is clearly related to reduced levels of plasma 25-hydroxyvitamin D. We conclude that hepatic osteomalacia is a vitamin D deficiency state and there is no need to suggest an unusual aetiology.

Vitamin and mineral nutrition in chronic alcoholics including patients with Korsakoff's psychosis

1. A group of 129 patients with chronic alcoholism were assessed for their nutritional status with respect to certain minerals and vitamins, and compared with control subjects. 2. In all subjects the plasma values were normal for calcium, magnesium and zinc. 3. As in other studies a seasonal variation was found in the plasma levels of 25-hydroxyvitamin D in the control subjects and the alcoholic subjects; in all seasons lower levels were found in the alcoholics than in the controls, but none of the alcoholic patients had results in the range found in osteomalacia. 4. The alcoholic subjects had low levels of ascorbic acid both in the plasma and in the leucocytes. 5. Although vitamin A and beta-carotene levels were within the reference range, the results in alcoholics were found to be lower than in the control subjects. 6. We suggest that subclinical vitamin deficiencies other than thiamine deficiency contribute to the cerebral impairment frequently found in alcoholism.