Luisa Alvarez

Alendronate is more effective than etidronate for increasing bone mass in osteopenic patients with primary biliary cirrhosis.

OBJECTIVES:Osteopenia increases the morbidity of primary biliary cirrhosis (PBC). In this study, we have compared two bisphosphonates, alendronate and cyclical etidronate, that inhibit osteoclast-mediated bone resorption and have examined their effects on bone mass in patients with this disease.METHODS:A total of 32 women with PBC were randomly assigned to receive alendronate (10 mg/day) or etidronate (400 mg/day) for 14 days every 3 months. Bone mineral density of the lumbar spine and proximal femur were measured initially and every 6 months. Bone fractures and markers of bone mineral metabolism were also evaluated.RESULTS:Sixteen patients were allocated to each group, which were comparable with respect to the severity of PBC and osteopenia. Thirteen patients in each group completed the 2-yr trial. Both treatments increased bone mineral density after 2 yr, although the increase at the lumbar spine and at the proximal femur was significantly higher in patients receiving alendronate than in patients on etidronate. This higher effect of alendronate paralleled with changes in the biochemical markers of bone turnover. No patient developed new vertebral fractures, but new peripheral fractures were detected in two patients on alendronate and in one on etidronate. There were no serious adverse effects. Neither treatment impaired liver function or cholestasis.CONCLUSIONS:Alendronate effectively increases bone mass and has greater antiresorptive power than etidronate in patients with primary biliary cirrhosis, and is associated with minor or no side effects.

Etidronate versus fluoride for treatment of osteopenia in primary biliary cirrhosis : Preliminary results after 2 years

BACKGROUND & AIMS Because osteopenia increases morbidity of primary biliary cirrhosis (PBC), the effects of cyclical etidronate vs. sodium fluoride on bone mass were compared in patients with PBC. METHODS Thirty-two women with PBC were randomly assigned to receive etidronate (400 mg/day during 14 days every 3 months) or fluoride (50 mg/day, enteric-coated tablets). Bone mineral density of the lumbar spine and proximal femur were measured initially and every 6 months. Bone fractures were also evaluated. RESULTS Sixteen patients were allocated into each group, which were comparable with respect to the severity of PBC and osteopenia. Thirteen patients with etidronate and 10 patients with fluoride completed 2 years in the study. In the etidronate group, bone mineral density increased in the lumbar spine (P = 0.02) and did not change in the proximal femur. In the fluoride group, lumbar bone mineral density did not change but femoral bone mass decreased, particularly in the Wards triangle. Two patients in the fluoride and none in the etidronate group developed new vertebral fractures, and the number of new nonvertebral fractures was similar in both groups. Neither treatment impaired liver function or cholestasis. CONCLUSIONS Cyclical etidronate is more effective and better tolerated than sodium fluoride in preventing bone loss in PBC.

Collagen‐Related Markers of Bone Turnover Reflect the Severity of Liver Fibrosis in Patients with Primary Biliary Cirrhosis

The influence of a nonskeletal disease with increased connective tissue synthesis or degradation in the collagen‐related markers of bone turnover has been evaluated in 34 women with primary biliary cirrhosis (PBC; age range 41–81 years), a disease with increased hepatic fibrosis, often associated with osteoporosis. Serum osteocalcin (BGP), and carboxy‐terminal (PICP) and amino‐terminal (PINP) propeptides of type I collagen were assessed as indexes of bone formation, whereas serum tartrate‐resistant acid phosphatase (TRAP), and cross‐linked carboxy‐terminal telopeptide of type I collagen (ICTP), and urinary hydroxyproline (HYP), pyridinoline (PYR), deoxypyridinoline (DPYR), and type I collagen cross‐linked N‐ (NTX) and C‐telopeptide (CTX) were measured as markers of bone resorption. The histologic stage of the disease and serum amino‐terminal propeptide of type III collagen (PIIINP) as an index of liver fibrogenesis were also evaluated. BGP levels were significantly lower, whereas PICP and PINP levels were higher in patients than in controls. Among the bone resorption markers, serum ICTP and urinary PYR, DPYR, HYP, NTX, and CTX levels were significantly higher in patients than in controls. Serum PIIINP levels were also increased in PBC patients. BGP did not correlate with PICP and PINP, but these markers of bone formation as well as ICTP, PYR, DPYR, and NTX correlated with serum PIIINP levels. Serum TRAP did not correlate with collagen‐related markers of bone resorption. Moreover, patients with PIIINP and bilirubin above normal levels had higher PICP, PINP, ICTP PYR, DPYR, CTX, and NTX. These markers correlated with the histologic stage of the disease, but not with osteopenia measured by densitometric procedures in 22 patients. In conclusion, collagen‐related markers of bone turnover do not reflect bone remodeling in PBC. The close association of these markers with PIIINP and the clinical and histologic stage of the liver disease suggests that they are influenced by liver collagen metabolism.

Usefulness of biochemical markers of bone turnover in assessing response to the treatment of paget’s disease

The aim of this study was to investigate the usefulness of biochemical markers of bone turnover for monitoring treatment efficacy of Pagets disease of bone, and also to evaluate the utility of biological variation data in choosing the best markers for assessment of biochemical response to therapy. Thirty-eight patients with Pagets disease were included in a prospective study. All received 400 mg/day of oral tiludronate for 3 months. In 31 patients that completed treatment, biochemical markers were measured at baseline and at 1 and 6 months after treatment ended. In serum we determined the levels of total alkaline phosphatase (tAP), bone alkaline phosphatase (bAP), procollagen type I N-terminal propeptide (PINP), and C-terminal telopeptide of type I collagen (sCTx). Urine samples were analyzed for hydroxyproline (Hyp) and for C- and N-terminal telopeptides of type I collagen (CTx and NTx, respectively). Quantitative bone scintigraphy was performed at baseline and at 6 months after discontinuation of therapy. A ratio for monitoring response to treatment was obtained for each marker. This ratio reflected the size of treatment response of the marker in relation to the value of its critical difference. Thus, ratio values of >1 indicated a significant decrease of the marker after therapy. In addition, response to therapy was evaluated according to disease activity. Mean values of all markers of bone turnover decreased significantly after therapy. Serum bAP and PINP and urinary NTx showed the highest percentage reduction (between 58% and 68%). Furthermore, serum bAP and PINP showed the highest ratios for monitoring changes induced by treatment, followed by serum tAP and urinary NTx. sCTx and urinary CTx as well as Hyp showed mean ratios for monitoring changes of <1, indicating a low sensitivity for monitoring treatment. Patients with polyostotic disease showed a continuous decrease in mean values for all markers at 6 months from the end of therapy, whereas, in monostotic patients, there was a trend toward increased levels at this timepoint. In conclusion, serum bAP and PINP were the most sensitive markers for monitoring treatment efficacy in Pagets disease, although serum tAP and urinary NTx were also sensitive markers for monitoring changes. Data on biological variation are useful for assessing actual changes induced by treatment.

Components of Biological Variation of Biochemical Markers of Bone Turnover in Paget's Bone Disease

The aims of this study were to evaluate the components of biological variation of the new markers of bone turnover in patients with Pagets bone disease and to compare the results with data obtained in healthy subjects. Fifteen patients with Pagets disease in a stable period of the disease and 12 healthy premenopausal women were included for a 1 year follow-up study. Within- and between-subject biological variation, indices of individuality, and critical differences were evaluated for the following biochemical markers: in serum, total (tAP), and bone (bAP) alkaline phosphatases, procollagen type I N-terminal propeptide (PINP) and beta-carboxyterminal telopeptide of type I collagen (sCTx); in urine, hydroxyproline (Hyp), and amino (NTx) and beta-carboxyterminal (CTx) telopeptides of collagen type I. Serum markers of bone turnover showed lower biological variability than urinary markers. Within-subject biological variation was higher in pagetic patients than in healthy subjects for all serum markers. In both groups, bAP presented the lowest within-subject biological variation. In pagetic patients, all markers presented indices of individuality of <0.6, indicating their usefulness for patient monitoring. Critical differences were lower for serum markers than for urinary markers. Among pagetic patients, serum bAP and PINP showed the lowest critical differences with values close to 30%, whereas urinary CTx presented the highest critical differences (near 70%). Conversely, in healthy subjects, tAP was the marker with the lowest critical differences, being two-fold higher in pagetic patients. This study confirms the lower sensitivity of urinary markers to detect significant changes and indicates that data obtained on biological variations from healthy populations cannot always be extrapolated to pathological conditions. In addition, serum bAP and PINP seem to be the markers that best reflect a significant change in activity of Pagets disease.

Biochemical markers of bone turnover after surgical menopause and hormone replacement therapy

The objective of this study was to evaluate the effect of surgical menopause and hormone replacement therapy (HRT) on the new biochemical markers of bone turnover. Fourteen women who had undergone surgical menopause and began HRT 3 months after surgery were recruited for a 1-year study. Results were compared with a control group of 31 healthy premenopausal women of similar age. Serum samples were obtained to determine total alkaline phosphatase, bone alkaline phosphatase, propeptides carboxy- and amino-terminal of type I procollagen (PICP, PINP), osteocalcin, tartrate-resistant acid phosphatase, and carboxy-terminal telopeptides of type I collagen (ICTP and serum CTX). Urine samples were analyzed for hydroxyproline, pyridinoline, deoxypyridinoline, alpha- and beta-carboxy-terminal telopeptides of type I collagen (alpha-CTX and beta-CTX), and amino-terminal telopeptide of type I collagen (NTX). Determinations were performed after 3 months of surgical menopause and after 3 and 9 months of HRT. All biochemical markers increased after menopause, and most of them normalized after 9 months of HRT. Serum PINP showed the highest proportion of increased values after surgery among bone formation markers (62%), as well as the highest mean percent increase (101%). Among bone resorption markers in postmenopausal women, urinary beta-CTX, alpha-CTX, NTX, and serum CTX showed the highest proportion of increased values (100%, 67%, 58%, 58%, respectively) as well as the greatest mean percent increase. They were also the markers with the most marked response to HRT. In conclusion, serum PINP is the most sensitive marker of bone formation, whereas beta-CTX is the most sensitive marker of bone resorption after surgical menopause. In addition, both markers showed the highest response after HRT.

Non‐Isomerized C‐Telopeptide Fragments Are Highly Sensitive Markers for Monitoring Disease Activity and Treatment Efficacy in Paget's Disease of Bone

A new resorption assay measuring non‐isomerized collagen type I C‐telopeptide fragments (α‐α CTX) was evaluated in a cohort comprising 32 Pagetic patients and 48 healthy controls. α‐α CTX was found to be a sensitive marker for assessing disease activity and monitoring treatment efficacy in Pagets disease of bone compared with isomerized CTX (β‐β CTX) and a number of other established bone turnover markers.

Lithocholic acid downregulates vitamin D effects in human osteoblasts.

Eur J Clin Invest 2010; 40 (1): 25–34

Effects of bilirubin and sera from jaundiced patients on osteoblasts: Contribution to the development of osteoporosis in liver diseases†

Low bone formation is considered to be the main feature in osteoporosis associated with cholestatic and end‐stage liver diseases, although the consequences of retained substances in chronic cholestasis on bone cells have scarcely been studied. Therefore, we analyzed the effects of bilirubin and serum from jaundiced patients on viability, differentiation, mineralization, and gene expression in the cells involved in bone formation. The experiments were performed in human primary osteoblasts and SAOS‐2 human osteosarcoma cells. Unconjugated bilirubin or serum from jaundiced patients resulted in a dose‐dependent decrease in osteoblast viability. Concentrations of bilirubin or jaundiced serum without effects on cell survival significantly diminished osteoblast differentiation. Mineralization was significantly reduced by exposure to 50 μM bilirubin at all time points (from −32% to −55%) and jaundiced sera resulted in a significant decrease on cell mineralization as well. Furthermore, bilirubin down‐regulated RUNX2 (runt‐related transcription factor 2) gene expression, a basic osteogenic factor involved in osteoblast differentiation, and serum from jaundiced patients significantly up‐regulated the RANKL/OPG (receptor activator of nuclear factor‐κB ligand/osteoprotegerin) gene expression ratio, a system closely involved in osteoblast‐induced osteoclastogenesis. Conclusion: Besides decreased cell viability, unconjugated bilirubin and serum from jaundiced patients led to defective consequences on osteoblasts. Moreover, jaundiced serum up‐regulates the system involved in osteoblast‐induced osteoclastogenesis. These results support the deleterious consequences of increased bilirubin in advanced chronic cholestasis and in end‐stage liver diseases, resulting in disturbed bone formation related to osteoblast dysfunction. (HEPATOLOGY 2011)

Effect of hemodialysis and renal failure on serum biochemical markers of bone turnover

The aim of the present study was to evaluate the effect of hemodialysis and renal failure on serum bone markers. Serum total alkaline phosphatase (TAP), procollagen type I aminoterminal propeptide (PINP), and Β-carboxyterminal telopeptide of type I collagen (Β-CTX), as well as intact parathyroid hormone (iPTH), creatinine, and total protein were measured in 14 patients with endstage renal disease (ESRD) before and at 1, 2, and 4 h during a hemodialysis session, and at the same sampling interval in 6 renal transplant recipients. The results were compared to those obtained in 20 healthy adults. All patients showed increased baseline mean values of PINP, Β-CTX, and iPTH. Β-CTX differed significantly between hemodialysis patients and renal transplant recipients. TAP and Β-CTX were the only markers which correlated with iPTH (P ≪ 0.05) and creatinine values (P ≪ 0.001), respectively. Renal transplant recipients did not show significant variations in the evolution of mean values of bone markers throughout the study, whereas, during the dialysis period, all the bone markers analyzed in the study showed a significant change. The change differed depending on the marker considered: Β-CTX showed a significant decrease at the end of the session, TAP increased at this time and, although PINP showed an initial increase during hemodialysis, no significant changes were observed at the end of the session. We conclude that bone markers are significantly influenced by hemodialysis, especially serum TAP and Β-CTX. ESRD is associated with an increase in these bone markers, in some cases related to iPTH values and in others to glomerular function. These findings should be taken into account when evaluating bone markers in these patients.