Acute effects of calcium infusion on hydroxyproline

Analysis of 645 patients with primary hyperparathyroidism with special references to cholelithiasis

OBJECTIVE The clinical picture of primary hyperparathyroidism (PHPT) has changed during the past 50 years. It is currently unknown whether or not PHPT is associated with an increased risk of cholelithiasis.

PATIENTS

To determine the frequency of cholelithiasis in PHPT we analyzed 645 consecutive patients seen at Prague University Hospital from 1992 through 2002 and compared them with a of normocalcaemic control group.

METHODS

We investigated 645 patients with proven PHPT (518 female and 127 males aged 20-80 years) during a period of 10 years. To determine the frequency of cholelithiasis in normal population we analyzed 2,015 patients receiving periodic health examination at an outpatient ward from January 1998 to December 1998 (1505 females and 510 males aged 24-85 years). A detailed history, physical examination, biochemical measurements and abdominal ultrasonography were done.

RESULTS

Cholelithiasis was proven in 157 of 518 women (30.3%) and in 11 of 127 men (8.66%) with PHPT. Their mean age was 59.67+/-12 years in women and 56.0+/-10 years in men. In the control group 260 of 1505 women (17.27%) and 54 of the 510 men (10.58%) had cholelithiasis. The mean age was 64.55+/-13.8 years in women and 61.2+/-12.4 in men. Only in the case of women, the difference was highly statistically significant (p<0.001). There were no significant differences between the mean values for the serum calcium level, bone alkaline phosphatase, total cholesterol, urinary hydroxyproline and body mass index in hyperparathyroid patients with and without cholelithiasis. However the hyperparathyroid women with cholelithiasis had an increased concentration of parathyroid hormone (236.1+/-56 pg/ml) compared with hyperparathyroid women without cholelithiasis (179.0+/-45 pg/ml), p<0.01.

CONCLUSION

The mechanism of PTH associated gallstone formation may involve inhibition of gallblader emptying, hepatic bile secretion and sphincter Oddi motility as well as modification of bile composition. While it might be difficult to prove it seems likely that the association of cholelithiasis with primary hyperparathyroidism in women with a high concentration of parathyroid hormone is more than merely coincidental and from our study it is obvious that a significant association exists.

The effects of three-month intravenous ibandronate on bone mineral density and bone remodeling in Klinefelter's syndrome: the influence of vitamin D deficiency and hormonal status

The aim of this study was to evaluate the effects of a 2-year treatment with intravenous ibandronate (2 mg every 3 months) and calcium (1000 mg daily) on bone mineral density (BMD) and bone markers in 14 patients with Klinefelter's syndrome who served as their own controls. During the follow-up of 5.9 years before the treatment was started, the mean rates of bone loss per year were 1.3, 0.9, and 0.6% in the lumbar spine, femoral neck, and total body, respectively. The rate of bone loss from the spine was significantly inversely related to both serum estradiol and testosterone. At the onset of treatment, the average age of the patients was 55.2 years (48-64 years), and T score, mean +/- SD, at the lumbar spine was -2.6 +/- 1.0. After 6 months, the mean serum CTX and PINP decreased by 39 and 55% below the pretreatment concentrations, respectively (P < 0.05). After 12 months of treatment, the patients gained mean +/- SD, 7.8 +/- 2.3% of BMD in the lumbar spine, 3.8 +/- 4.0% in the femoral neck, and 4.7 +/- 2.2% in the total body (P < 0.05). During the second year of treatment, all patients also received 700 IU of vitamin D daily. After 24 months of treatment, the patients gained 10.1 +/- 4.3% of BMD in the lumbar spine, 6.7 +/- 5.5% in the femoral neck, and 5.5 +/- 2.5% in the total body. The increase in BMD in the second year of ibandronate treatment was not significant. The rate of gain of BMD in the femoral neck was positively related to serum concentrations of testosterone and inversely related to 25-hydroxyvitamin D (P < 0.005). After the discontinuation of treatment, serum CTX and PINP increased to the pretreatment levels, and the lumbar spine and femur neck BMD decreased (P < 0.05). In conclusion, ibandronate was effective in increasing BMD at all sites, but the effects were adversely influenced by vitamin D insufficiency or deficiency. The overall changes in biochemical markers of bone remodeling were consistent with the antiresorptive effect of the drug.

Comparison of biochemical markers of bone remodelling in the assessment of the effects of alendronate on bone in postmenopausal osteoporosis

The effects of alendronate treatment on biochemical markers of bone remodelling and bone mineral density (BMD) were studied in 30 Caucasian women (postmenopausal for at least 3 years, age 42-76 years, with BMD of the lumbar spine at least 2 S.D. below the mean for mature, premenopausal women). The patients were randomly assigned to receive alendronate (10 mg/day) or placebo for 12 months (double blind). The study was subsequently extended to a second year of open alendronate treatment. The treatment with alendronate resulted in a significant and progressive increase in BMD of the lumbar spine and femoral neck. Under the treatment, the maximal decrease of biochemical markers of bone remodelling (osteocalcin in plasma, bone-specific alkaline phosphatase, N-terminal propeptide of type I procollagen and C-terminal telopeptide of type I collagen in serum, and cross-linked amino-terminal N-telopeptide and total hydroxyproline in urine) was observed at 6 months with no further change during the 2-year period. There were no significant differences in discriminating between patients treated for 1 year with alendronate or placebo using either the percentage change in spine BMD at month 12, or a single measurement of the marker at month 6, or log (percent of baseline at month 6 of value of the marker). In this respect, the power of all the biochemical markers were comparable. The markers are a valuable adjunct to the measurements of BMD, especially in the patients not showing an increase of 3% or more at the lumbar spine BMD after 1 year of treatment.

Beta 2-microglobulin does not behave as a biological marker of bone remodeling in patients with primary hyperparathyroidism

Parathormone has been shown to increase the secretion and production of lysosomal enzymes including tartrate-resistant acid phosphatase. All our 68 patients with proven primary hyperparathyroidism had signs of hyperparathyroid bone disease. Tartrate-resistant acid phosphatase and bone alkaline phosphatase activities are raised as a result of enhanced bone remodelling. Serum beta 2-microglobulin concentration in patients with primary hyperparathyroidism was normal 1.6 (1.4-1.8) mg/l versus 1.8 (1.7-2.2) mg/l in 51 control subjects. In hyperparathyroid patients, serum beta 2-microglobulin concentration does not correlate with plasma tartrate-resistant acid phosphatase activity which is known to be a sensitive biological marker of bone remodelling (r = 0.088). Our findings indicate that serum beta 2-microglobulin does not behave as a biological marker of remodelling in patients with enhanced remodelling in primary hyperparathyroidism.

Galactosyl hydroxylysine in assessment of Paget's bone disease

Urinary galactosyl hydroxylysine/creatinine ratio (GHL) was used to assess rates of bone collagen degradation and the activity of the pagetic lesion as well as for monitoring the rate and degree of suppression of bone resorption over 1 year in patients treated with 30 mg of intravenous pamidronate for 3 consecutive days. The clinical utility of GHL was compared with that of urinary hydroxyproline/creatinine and deoxypyridinoline/creatinine and with bone isoenzyme of serum alkaline phosphatase. The results suggest that GHL is a quantitative marker of the activity of Paget's bone disease. GHL is less sensitive than hydroxyproline, deoxypyridinolone and bone alkaline phosphatase in monitoring treatment of Paget's disease. The assay of GHL is easier, faster and less costly than that of hydroxyproline or deoxypyridinoline and it can be easily standardized.

Biochemical assessment of bone loss in patients on long-term thyroid hormone treatment

To test conditions under which thyroid hormone might be deleterious to bone, we studied a group of 58 patients who had undergone thyroidectomy because of thyroid cancer 1 to 21 years previously and were treated with steady doses of exogenous thyroid hormone. Vertebral bone density (BMD Z-score) was significantly reduced and biochemical indices of bone resorption (urinary hydroxyproline and plasma tartrate-resistant acid phosphatase activity) and of osteoblastic activity (plasma osteocalcin and bone isoenzyme of serum alkaline phosphatase) as well as the calculated prevalence of bone resorption relative to osteoblastic activity (HBP) were significantly increased in thyroid hormone-treated post-menopausal women but not in men and premenopausal women. The HBP as well as the biochemical indices of bone remodeling were significantly negatively correlated with serum TSH levels. In treated patients, BMD Z-score was significantly dependent on the HBP, menopausal state, duration of treatment and serum TSH levels. In conclusion, the further increase in bone resorption by thyroid hormone is predisposed by menopausal changes in bone turnover. The simultaneous evaluation of biochemical indices of bone resorption and formation improves the assessment of bone loss in patients treated with thyroid hormone in a suppressive dose.

The application of plasma tartrate-resistant acid phosphatase to assess changes in bone resorption in response to artificial menopause and its treatment with estrogen or norethisterone

Plasma tartrate-resistant acid phosphatase (TR ACP), urinary hydroxyproline excretion (UH), serum osteocalcin, and bone alkaline phosphatase isozyme were determined in a prospective study in 31 women who had undergone bilateral ovariectomy (OOX). Nine patients were followed up for 1 year without treatment and for the following 3 years when on mestranol (M) substitution. On the basis of UH, 22 patients were identified as having increased bone resorption (BR) within 3 months of OOX. Subsequently, 11 patients were treated with transdermal estradiol (E2) and 11 patients with norethisterone (norethindrone, NE). In untreated patients, the biochemical indices of BR peaked 3-6 months following OOX and biochemical indices of bone formation (BF) continued to increase from 3 until 12 months. The substitution with both E2 or M resulted in normalization in serum and urinary calcium, serum phosphate, renal threshold phosphate concentration (TmPO4/GRF), and biochemical indices of BR within 4 months of treatment. Biochemical indices of BF normalized within 6 months of treatment. In the M-treated group, these effects continued for 3 years of the follow-up. The hormonal substitution had a protective effect on cortical and lumbar spine bone mass. A significant decrease, but not to normal values, in biochemical indices of BR and a persistent elevation in indices of BF were found in NE-treated patients. Unlike E2, NE does not depress osteoblastic function. There is strong evidence supporting the utility of measurements of TR ACP in plasma in examination of women who had ovariectomies and in assessement of the efficacy of treatment.

Bone demineralization, biochemical indices of bone remodeling, and estrogen replacement therapy in adults with Turner's syndrome

The study centered on a controversy about whether long-term estrogen replacement therapy may ameliorate the osteoporosis seen in patients with Turner's syndrome. This study comprised 26 adult patients with Turner's syndrome (9 treated and 17 untreated or insufficiently treated) and 12 adult women with pure gonadal dysgenesis (8 untreated and 4 treated). A low bone density below -2 standard deviations from the age- and sex-matched predicted normal mean was documented by dual-photon absorptiometry of the lumbar spine in all the untreated and insufficiently treated patients, but only in 6 treated patients. The biochemical indices of bone resorption (urinary hydroxyproline excretion and plasma tartrate-resistant acid phosphatase activity), as well as osteoblastic function (serum osteocalcin and bone alkaline phosphatase isoenzyme), were significantly increased in untreated and insufficiently treated patients compared with treated patients. A significant negative correlation was found between biochemically documented osteoresorption and spinal bone mineral density corrected for age of the patients. Significant positive correlations were found between serum osteocalcin and bone alkaline phosphatase isoenzyme and between biochemical indices of bone resorption and formation. Although in the patients there was an evidence of a high bone remodeling rate, the rate of bone mass loss seemed to be low, comparable with that seen in oophorectomized women who had already passed their accelerated phase of bone loss. The results indicate that long-term hormonal replacement therapy is justified in gonadal dysgenesis, regardless of the karyotype of the patient, to prevent further bone mass loss.

Primary hyperparathyroidism and hyperuricaemia are associated but not correlated with indicators of bone turnover

Urate metabolism was studied in 53 patients with primary hyperparathyroidism. They had compared to controls significantly higher serum urate and reduction of the clearance of urate. In 14 of the tested patients with primary hyperparathyroidism serum urate was increased above normal limits. Six months after parathyroidectomy serum urate fell significantly from 365.3 +/- 75.7 mumol/l to 265.7 +/- 48.3 mumol/l, in 26 patients where urate measurements were available before as well as after surgery. Serum urate levels in our patients with primary hyperparathyroidism did not correlate with clearance of urate. Levels of serum urate cannot be entirely explained by the decrease in renal clearance of urate. Serum urate levels did not correlate with severity of skeletal changes expressed by serum B-ALP and urinary excretion of hydroxyproline. These results suggest that parathormone does not increase the part of the urate pool coming from the nucleic acids of the increased bone metabolism.

Age and sex dependency of the biochemical indices of bone remodelling

The values for the bone isoenzyme of serum alkaline phosphatase peak in the first two years of age, between 6 and 7 years of age, before the end of puberty and in the postmenopause. A population between the ages of 29 and 45 provides a reference population to which all other age groupings can be compared. A significant positive correlation was found between bone isoenzyme of serum alkaline phosphatase and urinary hydroxyproline excretion in children as well as after puberty. However, in the children the urinary hydroxyproline excretion was significantly higher when compared with the bone isoenzyme of alkaline phosphatase. A significant positive correlation was found between the bone isoenzyme of alkaline phosphatase and plasma tartrate-resistant acid phosphatase, irrespective of age and sex. The biochemical indices of bone remodelling correlated significantly with the growth rate in children and adolescents. The results are in good agreement with the concept of the coupling of bone formation to bone resorption.

Biochemical assessment of bone disease in multiple myeloma

In patients with multiple myeloma, with moderate and severe bone disease, the urinary hydroxyproline excretion was disproportionately elevated with respect to the activity of bone isoenzyme of alkaline phosphatase when compared with the relationship between the variables observed in 58 age- and sex-matched controls and in 50 healthy young subjects. A significant positive correlation was found between urinary hydroxyproline excretion and the clinical variables related to the extent of bone involvement in multiple myeloma (X-rays, patient's performance status, anaemia). In 9 out of 13 patients with moderate and severe bone disease the chemotherapy-induced remission was associated with a significant (p less than 0.05) rise in the activity of bone isoenzyme of alkaline phosphatase and decrease (p less than 0.005) in urinary hydroxyproline excretion. In successfully treated patients, the relationship between the biochemical variables indicated increased but proportionate extents of whole-body rates of bone formation and resorption. This was not the case in patients in whom no chemotherapy-induced remission was noted. The simultaneous evaluation of the activity of bone isoenzyme of serum alkaline phosphatase and urinary excretion of hydroxyproline improves the assessment of bone involvement in multiple myeloma and the efficacy of treatment.

Relationship of plasma tartrate resistant acid phosphatase to the bone isoenzyme of serum alkaline phosphatase in hyperparathyroidism

In 46 patients with primary hyperparathyroidism, in 21 non-dialysed patients with advanced renal failure, and in 52 patients on hemodialysis, a significant positive correlation was found between bone isoenzyme of serum alkaline phosphatase and plasma tartrate resistant acid phosphatase. In primary hyperparathyroidism, a significant positive correlation was found between the radiological degree of osteodystrophy and the biochemical parameters of bone remodelling. After removal of the parathyroid adenoma, only the tartrate-resistant acid phosphatase decreased to normal limits. Plasma tartrate resistant acid phosphatase was most significantly influenced by serum immunoreactive parathyroid hormone levels. In chronic renal failure, bone isoenzyme of serum alkaline phosphatase was most significantly influenced by serum immunoreactive parathyroid hormone levels, by hypocalcemia and by duration of hemodialysis. The results confirm that in hyperparathyroidism the extent of the whole-body rates of bone resorption and formation are approximately equal. The biochemical parameters can be used for serial assessment of the course of the disease but are not specific for diagnosis.

Bone isoenzyme of serum alkaline phosphatase in diabetes mellitus

Increased activity of bone isoenzyme of serum alkaline phosphatase was found in 52, 82 and 72% of the patients on dietary, oral agents, and insulin regimens, respectively. Significant positive correlations between the activity of bone isoenzyme and urinary hydroxyproline excretion in diabetes are similar to those found in osteoporosis. In stepwise regression analysis, negative correlations were found between the parameters of turnover of bone organic matrix and serum calcium levels; the influence of blood glucose levels in the expression of the biochemical parameters of bone metabolism was most pronounced in patients on oral agents. The results explain moderate hyperphosphatasia, known in diabetes, and support a metabolic etiology for the bone disease in diabetes mellitus.

Bone isoenzyme of serum alkaline phosphatase in acromegaly

In 37 patients with active acromegaly and in 15 patients with inactive acromegaly, activity of bone isoenzyme of serum alkaline phosphatase correlated (P less than 0.001) with serum concentration of immunoreactive growth hormone. By using stepwise regression analysis, the predication of serum growth hormone values based on serum levels of bone isoenzyme of serum alkaline phosphatase, gamma-glutamyl transferase and calcium in these patients with acromegaly was within 1 S.D. range in 37 patients and in only 2 patients was it out of 2 S.D. range. By using discriminant analysis, based on bone and liver isoenzymes of serum alaline phosphatase and urinary hydroxyproline excretion, 87%, 60% and 97% of the classification of patients with active and inactive acromegaly and healthy adults, respectively, was correct. The multivariate approach offers a quantitative appraisal of the biochemical parameters of peripheral growth hormone action used as an indicator of growth hormone concentration in patients with acromegaly.

Relationship of the activity of the bone isoenzyme of serum alkaline phosphatase to urinary hydroxyproline excretion in metabolic and neoplastic bone diseases

A significant correlation between the activity of the bone isoenzyme or serum alkaline phosphatase and the urinary hydroxyproline excretion in osteomalacia, osteoporosis, primary hyperparathyroidism with osteodystrophy, Paget's disease, secondary bone tumours, and in a control group was found (P less than 0.001). This close correlation was not observed between these variables in patients with active acromegaly. Diagnosis determined from these indices of formation and turnover of bone matrix agreed with that established by histological and histochemical examination of bone, by X-ray investigation of the skeleton, and by the radionuclear 85Sr test. The relationship between the activity of bone isoenzyme and urinary hydroxyproline excretion differed in metabolic bone diseases with a high bone turnover, in patients with osteoporosis and in patients with early osteoclastic bone metastases.