Potential protection by cyclosporin against glucocorticoid effects on bone

Ethnic Differences in Osteoporosis After Cardiac Transplantation

Cardiac transplantation is associated with a high risk of fracture. African Americans (AAs) are believed to have a lower risk of osteoporosis than Caucasians, but it is not clear whether they are also protected from osteoporosis resulting from the use of glucocorticoids and/or organ transplantation. We examined possible ethnic differences in 33 cardiac transplant recipients (16 AAs) in a cross-sectional analysis. In addition to bone mineral density and vertebral fracture assessment, we also compared biochemical variables, trabecular bone score, total body dual-energy X-ray absorptiometry, and disability. Overall fracture rates were low in both groups, with only 6 total subjects with fractures on vertebral fracture assessment or history of fracture. While T-scores were similar between groups, Z-scores were lower in AA with the difference reaching statistical significance when controlling for important covariates. The trabecular bone score was also lower in AAs than in Caucasians even when adjusting for age and tissue thickness (1.198 ± 0.140 vs 1.312 ± 0.140, p = 0.03). While AAs are generally thought to be protected from osteoporosis, our study instead suggests that AAs may be at higher risk of bone deterioration after cardiac transplantation and may need to be managed more aggressively than suggested by current guidelines.

Osteoprotegerin and receptor activator of nuclear factor-kappaB ligand system in the early post-operative period of liver transplantation

BACKGROUND

The precise mechanism that leads to accelerated bone resorption in the early post-transplant period remains unclear. Recent data suggest that osteoprotegerin (OPG) and its ligand receptor activator of nuclear factor-kappaB ligand (RANKL) constitute a novel cytokine system that can influence the function of both bone and immune cells. The aim of our study was to assess OPG and RANKL concentrations in the early post-operative period of liver transplantation.

METHODS

Serum OPG and RANKL levels were measured in 30 patients who underwent liver transplantation at 1, 7 and 14 d post-operatively. These values were compared with 22 age- and sex-matched healthy controls. Plasma sodium, creatinine, aspartate-aminotransferase, alanine-amino transferase, gamma-glutamyl transferase, alkaline phosphatase, bilirubin, albumin, prothrombin time, tacrolimus and cyclosporine levels were measured in each patient.

RESULTS

We found a significant increase in OPG levels in the early post-operative period compared with the control group: day 1 (10.42 pmol/L, range 3.80-17.50 vs. 3.91 pmol/L, range 1.20-6.60; p = 0.0001), day 7 (6.90 pmol/L, range 3.00-15.30 vs. 3.91 pmol/L, range 1.20-6.60; p = 0.0001) and day 14 (5.76 pmol/L, range 2.60-10.70 vs. 3.91 pmol/L, range 1.20-6.60; p = 0.001). Similarly, serum RANKL levels were significantly higher than in the control group in this period, day 1 (0.123 pmol/L, range 0.010-0.420 vs. 0.054 pmol/L, range 0.010-0.300; p = 0.02), day 7 (0.236 pmol/L, range 0.010-0.720 vs. 0.054 pmol/L, range 0.010-0.300; p = 0.0004) and day 14 (0.137 pmol/L, range 0.010-0.520 vs. 0.054 pmol/L, range 0.010-0.300; p = 0.007). No correlation was found between OPG levels and RANKL, ischemic times, liver function tests, albumin, sodium or creatinine concentrations and tacrolimus or cyclosporine levels.

CONCLUSIONS

A significant amount of OPG and RANKL is released in the early post-transplant period of liver transplantation. This might be explained by an activation of the immune system caused by the allograft. Therefore, the RANKL/OPG system may be involved in the pathophysiological evolution of transplantation osteoporosis.

Clodronate treatment of established bone loss in cardiac recipients: a randomized study

BACKGROUND

Bone loss has been reported as a complication after heart transplantation (HTx), and the increase in bone fractures is an effective problem. Treatment of osteoporosis has obtained mixed results. In this study we evaluate the effect of treatment with an oral bisphosphonate.

METHODS

Sixty-four patients with low mineral density 6 months after HTx were randomized as follows: Group A received oral clodronate (1600 mg/day in two divided doses), and Group B received placebo. Every patient was also treated with 2000 mg/day of oral calcium carbonate. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry at the lumbar spine, 1/3 and 1/10 of the distal nondominant forearm before and after 12 months of treatment. Laboratory tests were performed at 3, 6, and 12 months of treatment.

RESULTS

All patients demonstrated manifest bone loss 6 months after HTx compared with normal non-HTx controls (P=0.0001). After 1 year of clodronate therapy, BMD at the lumbar spine increased from 0.77+/-1.4 g/cm(2) to 0.86 g/cm(2) (P=0.02). Laboratory tests did not show any significant variation, except for the bone isoenzyme of alkaline phosphatase, which showed a significant decrease after 1 year of treatment. The incidence of new fractures was 9.3% in the placebo group and 0% in the clodronate group. Therapy was well tolerated without impact on graft function.

CONCLUSIONS

One year of clodronate therapy induced a significant increase in BMD at the lumbar spine in our HTx patients. Treatment was well tolerated without onset of new bone fractures.

Prevention of osteoporosis after cardiac transplantation: a prospective, longitudinal, randomized, double-blind trial with calcitriol

BACKGROUND

Accelerated bone loss is a well-recognized complication after cardiac transplantation (HTx) due to immunosuppressive therapy. The purpose of this prospective, longitudinal, randomized, placebo-controlled, double-blind study was to investigate the effect of calcitriol (1,25-dihydroxyvitamin D3) in the prevention of bone loss and fracture rate after HTx.

METHODS

Basic therapy included 1000 mg of calcium daily and sex hormone replacement in hypogonadal patients. A total of 132 patients (111 male, 21 female; mean age: 51+/-10 years; 35+/-25 months after HTx) were randomized to 0.25 microg of calcitriol or placebo. Bone mineral density (BMD, g/cm2; T score, %) of the lumbar spine and x-rays for the assessment of vertebral fractures were performed at baseline and after 12, 24, and 36 months. Biochemical indexes of mineral metabolism were measured every 3 months.

RESULTS

Overall BMD was significantly decreased after HTx (T score 87+/-13%). BMD increased continuously within the study period in the calcitriol group (1 year: 2.2+/-4.8%; 2 years: 3.9+/-5.4%; 3 years: 5.7+/-4.4%) as well as in the placebo group (1 year: 1.8+/-4.9%; 2 years: 3.7+/-6.5%; 3 years: 6.1+/-7.8%) without statistical difference between the groups. Fracture incidence was low during the study interval (1 year: 2.0%; 2 years: 3.4%; 3 years: 0%). Hypogonadism (20%) was associated with a lower BMD (78+/-12% vs. 88+/-12%; P<0.01) and a higher increase (35%) after hormone replacement in comparison to normogonadal patients. Increased intact parathyroid hormone and bone resorption markers decreased significantly during therapy.

CONCLUSIONS

Calcium supplementation and sex hormone replacement in hypogonadism proved a sufficient long-term prevention therapy to improve decreased BMD and to prevent fractures after HTx. Besides immunosuppression, both concomitant hypogonadism and secondary hyperparathyroidism play a major role in the long-term bone loss and should therefore be monitored and treated adequately. Low-dose calcitriol demonstrated no significant extra benefit regarding BMD and fracture rate in the long-term period after HTx.

Reduced bone mineral density in men after heart transplantation

Heart transplantation is associated with rapid bone loss and an increased prevalence and incidence of fractures. The aim of the present study was to compare the bone mineral density (BMD) of 30 heart transplant (HT) recipients to that of 31 chronic heart failure (CHF) patients waiting for transplantation and to determine their biochemical markers of bone resorption and hormone levels. The BMD of lumbar spine and proximal femur was determined by dual-energy X-ray absorptiometry. Anteroposterior and lateral radiographs of the thoracic and lumbar spine were also obtained. The mean age of the two groups did not differ significantly. Mean time of transplantation was 25.4 +/- 21.1 months (6 to 88 months). Except for the albumin levels, which were significantly higher, and magnesium levels, which were significantly lower in HT patients when compared to CHF patients, all other biochemical parameters and hormone levels were within the normal range and similar in the two groups. Both groups had lower BMD of the spine and proximal femur compared to young healthy adults. However, the mean BMD of HT patients was significantly lower than in CHF patients at all sites studied. Bone mass did not correlate with time after transplantation or cumulative dose of cyclosporine A. There was a negative correlation between BMD and the cumulative dose of prednisone. These data suggest that bone loss occurs in HT patients mainly due to the use of corticosteroids and that in 30% of the patients it can be present before transplantation. It seems that cyclosporine A may also play a role in this loss.

Prevention of bone loss in cardiac transplant recipients. A comparison of biphosphonates and vitamin D

Bone mineral density is already abnormally reduced at the moment of cardiac transplantation and bone loss occurs at an impressive rate in the first postoperative year. The aim of the study was to compare two prophylactic medical regimens as to their efficacy in mitigating bone loss after transplantation. Forty-eight consecutive recipients were randomized to receive either alternating calcium carbonate and disodium etidronate (group A) or a daily supplement of calcium carbonate and alphacalcidol (group B). Bone mineral density measurements were performed immediately before hospital discharge and 6, 12, and 24 months after surgery using dual energy X-ray absorptiometry. Clinical events were recorded and roentgenograms of the spine were performed postoperatively and 1 and 2 years later. In both treatment groups bone loss remained significant at the level of the lumbar spine in the first postoperative year (P<0.005) and at the level of the femoral neck in the first (P<0.005) and the second (P<0.06) year after transplantation. Six months after transplantation, however, patients receiving alphacalcidol had a significant reduction in bone loss at the level of the lumbar spine (P=0.047) and at the level of the femoral neck (P=0.043). At the level of the femoral neck this decrease in bone loss was even more pronounced in the second postoperative year (P<0.001). In the group of patients treated with disodium etidronate, 4 recipients needed additional hospitalizations for treatment of symptomatic fractures at the level of the lumbar spine or the femoral neck. No such events happened in recipients receiving vitamin D supplements. Prophylactic administration of calcium carbonate and alphacalcidol after cardiac transplantation reduces bone loss and seems to decrease osteoporotic complications.

Bone loss after liver transplantation is not prevented by cyclical etidronate, calcium and alphacalcidol. The Liver Transplant Group, Groningen

After orthotopic liver transplantation (OLT) bone mass rapidly declines and vertebral fracture rate increases. We studied bone loss and parameters of bone turnover in 53 consecutive patients. In an attempt to reduce bone loss the patients were prophylactically treated with cyclical etidronate in addition to daily 1 alpha-hydroxyvitamin D3 and calcium. During the first 3 months after transplantation median lumbar spinal bone mineral density (BMD) decreased 4.5%; subsequently no significant changes occurred. Median hip BMD continued to fall during the first post-transplantation year and deteriorated 7% over the whole study period. New vertebral fractures were seen in 25% of the patients, which is not lower than previously reported rates in patients not receiving cyclical etidronate. Parathyroid hormone levels increased after OLT (p = 0.01), but remained within normal ranges. Urinary hydroxyproline levels were increased and normalized in the second half-year after OLT. Elevated fasting calciuria increased further after OLT. 1,25-Dihydroxy-vitamin D3 levels were lowered pre-OLT (25 vs 66 pmol/ 1, p < 0.001) and normalized at 3 months after OLT. Serum osteocalcin concentrations remained unchanged and were reduced compared with levels in healthy controls. In summary, increased bone resorption occurs after OLT with persistent decreased bone formation, leading to vertebral fracture in 25% of patients. Etidronate, 1 alpha-calcidol and calcium treatment did not prevent bone loss.

Bone mineral status in end-stage liver disease and the effect of liver transplantation

BACKGROUND

The aim of this study was to determine bone mass at different skeletal sites in patients with end-stage liver disease and the effect of liver transplantation on bone mineralization.

METHODS

Bone mineral density in different skeletal regions was measured by photon absorptiometry in 25 patients with chronic liver disease, and the measurements were repeated in nine patients after orthotopic liver transplantation.

RESULTS

In patients with liver failure bone mass values were not significantly different from those of controls. After liver transplantation bone mass decreased significantly during the first 6 posttransplant months at the distal radius, lumbar spine, and femur (p < 0.01) and was still below pretransplant values at the 12th posttransplant month. Serum osteocalcin increased significantly from the 3rd month after transplantation (from 6.9 +/- 4.4 to 12.0 +/- 6.5 micrograms/l; p < 0.0001) and remained increased throughout the first posttransplant year.

CONCLUSION

Early and accelerated bone loss occurred after liver transplantation. This bone reduction seems to be mainly the result of increased bone resorption, possibly related to corticosteroid therapy.

Calcitonin and bisphosphonates treatment in bone loss after liver transplantation

Osteopenia is a major complication of orthotopic liver transplantation (OLT). However, no effective therapy for bone disease has been defined. We have studied vertebral bone mineral density (VMD) and fasting serum markers of bone formation [bone gla protein (BGP), procollagen I carboxyterminal peptide (PICP)] and metabolism (serum Ca, P, intact parathyroid hormone (iPTH), 25OHD3 and 1,25(OH)2D3) in 120 patents after OLT. VMD was measured by dual-energy X-ray absorptiometry (DXA) using a Hologic QDR 1000 densitometer on two occasions, 12 months apart. Patients with OLT had a VBD significantly lower compared with age- and sexed-matched Spanish controls (P < 0.05). Prevalence of osteoporosis (Z score below -2 SD) was 35.8%. Serum BGP (8.6 +/- 0.7 ng/ml) and PICP (222.9 +/- 81.9 ng/dl) were higher than those of controls. However, serum calcium, phosphorus, iPTH, 25OHD3, and 1,25(OH)2D3 were within normal range. Patients with osteoporosis were randomly treated with 40 IU/day of calcitonin i.m. (Diatin, Ferrer Int. Laboratories) (n = 17) or 400 mg p.o., 15 days every 3 months, of sodium ethiodronate (Difosfen, Rubio Laboratories) (n = 23). All patients received 500 mg/12 hours of elemental calcium p.o. After 12 months of treatment, a significant increment of vertebral mineral density (VMD) was observed (6.4% and 8.2%, respectively). Serum BGP and PICP values remained elevated without a difference between the two drugs. Our results indicate that antiresorptive drugs may be of benefit in the high turnover osteoporosis of OLT recipients.

Timing and quantification of bone loss in cardiac transplant recipients

To evaluate osteopenic bone disease in heart transplant patients, we prospectively measured bone mineral density (BMD) in 33 consecutive male recipients before hospital discharge and 1 year later, using dual photon absorptiometry. At hospital discharge BMD measurement at the lumbar spine was 90% of that expected in healthy age- and sex-matched controls (p = 0.005). One year later BMD had further decreased by 8.5% at the lumber spine and by 10.4% at the femoral neck (P = 0.0001). Five patients suffered vertebral compression fractures during the 1st postoperative year. Our results indicate that osteopenia of the lumbar spine is already present at the time of hospital discharge after transplantation and that further bone loss occurs at considerable rate during the 1st postoperative year at the lumber spine and at the femoral neck.

Parathyroid function in cardiac transplant patients: evaluation during physical exercise

The survival rate of heart transplant patients has increased considerably since the development of new immunosuppressive drugs. In the long term, however, cardiac transplantation results in a high incidence of osteoporosis which represents a major functional handicap. To examine whether patients in the early stages have impaired phosphocalcic metabolism, intact parathyroid hormone (PTH 1-84), native osteocalcin, ionized Ca++ and pH were measured at rest and during muscular exercises a dynamic test used to override circadian and ultradian PTH variations. A group of 12 patients receiving the usual immunosuppressive therapy, which is mainly an association of cyclosporin and prednisolone, and 8 sedentary control subjects performed a square-wave endurance test at the same relative intensity for 30 min. No patient had previous bone disease and the period since transplantation was 12.2 +/- 2.7 months. For the transplant patients, initial PTH concentrations and responses to exercise were higher (P < 0.01) compared to the control subjects with a dramatic increase after 10 min of recovery. From higher (P < 0.001) resting concentrations, osteocalcin further increased during exercise (P < 0.01) in the heart transplant group but not in the control subjects. In both groups pH showed the same time-course with a rapid fall during exercise (P < 0.05) and Ca++ concentrations increased during the exercise period. (P < 0.01 for patients; P < 0.05 for controls) with a significant fall in both groups after 10 min of recovery (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Bone loss after orthotopic liver transplantation

PURPOSE

We assessed changes in body composition and bone loss following liver transplantation to determine if bone loss is related to the underlying liver disease or to other factors such as sex, menopause, or graft rejection episodes.

PATIENTS AND METHODS

Our cross-sectional study component compared bone mass and body composition in 31 patients at 1 year after liver transplantation versus 33 pregraft patients with chronic liver disease. Bone mass was measured by dual energy X-ray absorptiometry (DXA) using anteroposterior views of the total body to determine bone mineral content (BMC), and of the lumbar spine to assess bone mineral density (BMD). The body fat content was also determined by DXA. Radiographs of the thoracic and lumbar spine were also obtained. In our longitudinal study component, 16 patients from the pregraft group underwent bone mass assessment again 1 year after transplantation.

RESULTS

Graft patients and pregraft patients both had reduced lumbar spine BMD compared to age- and sex-matched normal values (P < 0.001). A 4.75% increase in body fat content was observed after liver transplantation (P < 0.05). In the cross sectional study, bone mass of the spine and total body were not different in pre- and posttransplantation patients. However, the longitudinal study revealed significant decreases in spinal BMD and total body BMC, with a mean 3.5% decrease and a rate of loss of 0.55% per month. In addition, a dramatically high prevalence (29%) of vertebral fractures was observed in grafted patients, contrasting with a low prevalence (8.4%) of fractures in pregraft patients. Menopause, primary biliary cirrhosis, and chronic alcohol abuse were the principal contributing factors for osteoporosis. Patients with vertebral fractures had a marked 17.4% decrease of the lumbar spine BMD (P < 0.001) and a 22% decrease in total BMC when compared to patients without fractures (P < 0.01).

CONCLUSION

Patients with orthotopic liver transplantation for chronic liver disease evaluated 1 year after transplantation have a high prevalence of vertebral fractures. Cross sectionally, bone mass was not different in patients before and after transplantation, but the longitudinal study showed that liver transplantation induced a marked and rapid bone loss. Bone loss due to transplantation could enhance the risk of new vertebral fractures, as shown by the high prevalence of vertebral fractures. These results emphasize the need to identify patients with low bone mass by bone densitometry before transplantation.

Mechanisms of rapid bone loss following cardiac transplantation

Rapid bone loss after orthoptic cardiac transplantation (OHTX) is a major problem; however, the mechanisms are poorly understood. To investigate these mechanisms we measured biochemical and hormonal indices of bone turnover serially in 25 patients (21 men, 4 women) after OHTX. Serum osteocalcin was reduced immediately post-OHTX (2.2 +/- 0.5 ng/ml) but rose significantly by 6 and 12 months (14.1 +/- 2.5 and 15.7 +/- 2.2 respectively). Bone resorption indices (urinary hydroxyproline/creatinine and calcium/creatinine ratios) were increased immediately post-OHTX but fell by 6 months. Serum testosterone was reduced in males but recovered towards normal values by 6-12 months. Regression analysis showed lumbar bone loss was predicted independently by the change in both serum osteocalcin and testosterone. The data suggest that bone loss post-OHTX is due to a combination of accelerated turnover and hypogonadism.

Immunosuppressive therapy and the skeleton

Glucocorticoids and other immunosuppressive drugs, such as cytoclosporine A, are increasingly used today. One of the most common clinical situations in which they are prescribed is for immunosuppression after organ transplantation. These drugs have diverse effects on the skeleton, however, and one of the most common sequelae of organ transplantation is osteoporosis and fractures. Patients treated with immunosuppressive drugs should be carefully evaluated for osteoporosis, preferably prior to or at the time of initiation of immunosuppressive therapy. They should be followed carefully with sequential bone-density measurements and biochemical indices of bone turnover. Measures to prevent bone loss should be initiated early in the course of immunosuppressive therapy.

Osteoporosis and bone morbidity in cardiac transplant recipients

PURPOSE

To evaluate the incidence and etiology of osteopenia and pathologic fractures in cardiac transplant recipients.

PATIENTS

Thirty-one adult male cardiac transplant recipients and 14 adult men with congestive heart failure (CHF) awaiting cardiac transplantation.

METHODS

Assessment of indices of bone and mineral metabolism and of bone mineral density (BMD) by dual-energy x-ray absorptiometry.

RESULTS

BMD in the proximal femur was below normal in both groups compared to that in age-matched control subjects, whereas BMD in the lumbar spine was normal. There was no significant difference in BMD at any site between the two groups. No clinical parameter predicted BMD. In all patients, laboratory indices of bone mineral metabolism, except parathyroid hormone (PTH) levels, were normal and not statistically different between the two groups. CHF patients had a trend toward elevations of PTH, 1,25-dihydroxyvitamin D, and urinary calcium excretion compared to transplant patients. Eight of 31 transplant patients and 2 of 14 CHF patients had vertebral compression fractures (c2 = 11.8, p < 0.0006). Transplant recipients with fractures had twice as many rejection episodes as did transplant patients without fractures, but did not differ in cumulative dose of steroids. Two patients developed avascular necrosis of the femoral head following transplantation.

CONCLUSIONS

Cardiac transplant recipients and patients with CHF awaiting transplantation had decreased hip BMD, but normal spine BMD. Although immunosuppressive therapy did not appear to influence bone mass, loop diuretics prior to transplantation may have stimulated a mild secondary increase in PTH that could have differentially caused loss of bone density at the hip in both groups. Pulse corticosteroids used in treating rejection may have contributed to the increased incidence of vertebral fractures in transplant patients. These data suggest that severe CHF with its associated diuretic use and decreased activity are primary contributors to osteopenia in these patients.

Interpretation and clinical significance of alkaline phosphatase isoenzyme patterns

Alkaline phosphatase (ALP, EC 3.1.3.1) is a membrane-bound metalloenzyme that consists of a group of true isoenzymes, all glycoproteins, encoded for by at least four different gene loci: tissue-nonspecific, intestinal, placental, and germ-cell ALP. Through posttranslational modifications of the tissue-nonspecific gene, for example, through differences in carbohydrate composition, bone and liver ALP are formed. Nowadays, most commercially available methods for separating or measuring ALP isoenzymes are easy to perform and sensitive and allow for reproducible and quantitative results. As more isoenzymes and isoforms have been characterized, confusion has arisen due to the many different names they were given. For the sake of simplicity and because of structural analogies, we propose an alternative nomenclature for the ALP isoenzymes and isoforms based on their structural characteristics: soluble, dimeric (Sol), anchor-bearing (Anch), and membrane-bound (Mem) liver, bone, intestinal, and placental ALP. Together with lipoprotein-bound liver ALP and immunoglobulin-bound ALP, these names largely fit the many forms of ALP one can encounter in human serum and tissues. The clinically relevant isoenzymes are sol-liver, Mem-liver, lipoprotein-bound liver, and Sol-intestinal ALP in liver diseases, and Sol-bone and Anch-bone ALP in bone diseases. Many different isoenzyme patterns can be found in malignancies and renal diseases. This test provides the clinician with valuable information for diagnostic purposes as well as for follow-up of patients and monitoring of treatment. However, ALP isoenzyme determination will only provide clinically useful information if the patterns are correctly interpreted. In this respect, care should be taken to use the proper reference ranges, taking into account the age and sex of the patient. A normal total ALP activity does not rule out the presence of an abnormal isoenzyme pattern, particularly in children. Separating ALP into its isoenzymes adds considerable value to the mere assay of total ALP activity.

Bone loss after cardiac transplantation: effects of calcium, calcidiol and monofluorophosphate

Of 203 patients who underwent cardiac transplantation and were given long-term treatment with cyclosporine and 0.3 mg/kg per day prednisone, 123 were studied prospectively for at least 6 months and 46 for up to 2 years to evaluate the effects on lumbar bone mineral density (BMD) and calcium metabolism of a combined therapy with calcium, calcidiol and disodium monofluorophosphate (MFP). The population was arbitrarily assigned to one of two groups. Group I consisted of patients who had a lumbar spine BMD Z score above -1.5 SD as compared with an age- and sex-matched population and no vertebral fractures. They received daily 1 g elemental calcium and 25 micrograms (1000 IU) calcidiol. Group II consisted of patients who received daily the same doses of calcium and calcidiol combined with 200 mg MFP, and was divided into two subgroups: (a) osteopenic subjects who had a lumbar spine BMD Z score below -1.5 SD without vertebral fractures and (b) osteoporotic subjects with vertebral fractures. If serum creatinine was higher than 140 mumol/l the daily dose of MFP was tapered to 100 mg. Fifty-four and 27 patients from group I and 38 and 19 patients from group II were followed respectively for 12 and 24 months. In both groups serum parathyroid hormone levels were significantly reduced from the twelfth month in parallel with a significant increase in serum 25-OHD levels. No decline in lumbar BMD occurred in non-osteopenic and non-osteoporotic patients (group 1) who received the calcium and calcidiol supplement. In group II, where MFP was added, a significant and linear increase in lumbar BMD was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteoporosis after cardiac transplantation

PURPOSE

The purpose of this study was to determine the prevalence of osteopenia and fractures and to describe the biochemical indices of mineral metabolism in patients who have undergone cardiac transplantation.

PATIENTS AND METHODS

Forty adult patients who had received a cardiac transplant between 1982 and 1990 and who were receiving immunosuppressive therapy with prednisone and cyclosporine A were studied. Bone densitometric measurements by dual-energy x-ray absorptiometry of the lumbar spine and femoral neck and radiographs of the thoracic and lumbar spine were obtained for all patients. Routine serum and urine biochemical values as well as more specialized biochemical analyses (intact parathyroid hormone, metabolites of vitamin D, and osteocalcin) were obtained.

RESULTS

Osteopenia was present in 28% of the patients at the lumbar spine and 20% of the patients at the femoral neck. Vertebral fractures were present in 35% of patients. In contrast to other patients receiving glucocorticoids, serum osteocalcin, a marker of bone formation, was elevated in 60% of patients.

CONCLUSIONS

Osteopenia and vertebral fractures are common in patients after cardiac transplantation. The presence of elevated osteocalcin levels suggests that the pathogenesis of the osteoporosis in these patients differs from that of glucocorticoid-induced osteoporosis.

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)

Reactivity of pretransplant cytotoxic antibodies to a selected HLA panel is not influenced by cyclosporin A, with or without plasma exchange

The influence of 6 weeks of cyclosporin A (CYA), followed by a further 6 weeks of this agent in combination with plasma exchange (PE), was defined on panel reactivity and titre of preformed cytotoxic antibodies in stable patients on haemodialysis awaiting renal transplantation. Nine individuals with antibodies to 30% or more of the donor panel were entered into the study, but three failed to complete the programme. Comprehensive data are available on the remaining six patients, one of whom was studied twice. The pattern of reactivity to the panel was unaltered, but antibody titres were significantly reduced (P less than 0.006). In one patient, a lymphocytoxic crossmatch performed between the patient and an HLA-haploidentical sibling in the last week of the trial was positive, suggesting that neither procedure was successful in removing an antibody directed against the HLA antigens of a family donor. Three cadaver renal transplants were performed during or after the trial, and while two of the grafts were unsuccessful, one survives at 60 months, with good function. From these data it is concluded that neither cyclosporin A nor its combination with plasma exchange have any effect on the panel reactivity of preformed cytotoxic antibodies, whereas the titres were significantly reduced. An important and serious side effect of the apheresis procedure was the loss of fistulae in two patients.