Treatment of Paget's disease of bone with synthetic salmon calcitonin

Salmon calcitonin: a review of current and future therapeutic indications

Salmon calcitonin, available as a therapeutic agent for more than 30 years, demonstrates clinical utility in the treatment of such metabolic bone diseases as osteoporosis and Paget's disease, and potentially in the treatment of osteoarthritis. This review considers the physiology and pharmacology of salmon calcitonin, the evidence based research demonstrating efficacy and safety of this medication in postmenopausal osteoporosis with potentially an effect on bone quality to explain its abilities to reduce the risk of spine fracture, the development of an oral salmon calcitonin preparation, and the therapeutic rationale for this preparation's chondroprotective effect in osteoarthritis.

Analysis of calcitonin and its analogues by capillary zone electrophoresis and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry

Capillary zone electrophoretic (CZE) separations and mass spectrometric analysis of salmon calcitonin and related analogues were performed to generate electrophoresis and mass fingerprints for quality control of the recombinant polypeptide pharmaceutical salmon calcitonin. The calcitonins and their corresponding tryptic digests were successfully separated by CZE at low pH in fused silica capillaries dynamically modified with poly-cationic polymers. The poly-cationic modified inner surface of the fused silica capillaries generated a strong anionic electroosmotic flow (EOF). Analytes of negative, neutral, and positive charge were all swept through the capillary toward the positive electrode. Compared to Polybrene-coated capillaries, capillaries coated with PEI showed a markedly slower but much more stable electroosmotic flow. The migration order of the analytes was predicted by comparing approximate values of the charge to (molecular mass)2/3 ratios. The predicted migration order was confirmed by off-line analysis of CZE fractions with matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS).

Treatment of patients with Paget's disease of bone

Paget's disease is a progressive bone disease, monostotic or polyostotic, characterised by hypertrophy of affected bones and accelerated disorganised bone remodelling. It results in bone deformities and pain, with a risk for articular and neurological complications, and fractures. The risk of complications, and thus the therapeutic decision, is a function of the age of the patient, and the severity and the activity of the disease. Bisphosphonates are first-line therapy for Paget's disease, and the advent of the new bisphosphonates permits a dramatic improvement in treatment. The optimal treatment regimen should obtain normalisation or quasi-normalisation of markers of bone remodelling. This result has the potential for a long-term control of the disease.

Morning or evening administration of nasal calcitonin? Effects on biochemical markers of bone turnover

The purpose of this study was to examine the effect of intranasal salmon calcitonin (sCT) administration (200 IE), given either in the morning (8:00) or evening (21:00), on the known circadian variation in biochemical markers of bone turnover. An open, placebo-controlled, randomized, crossover study, with three 24 h studies of blood samples drawn every third hour and urine collected in 3 h aliquots was undertaken. Subjects consisted of nine healthy postmenopausal women, aged 58 +/- 7 years. Urinary CrossLaps (a measure of bone resorption) was measured by ELISA and corrected for creatinine (Cr). Serum osteocalcin (sOC) was measured by radioimmunoassay (RIA). The first 24 h study was performed without intervention. Prior to this control study the participants were randomized to either morning (8:00) or evening (21:00) sCT (200 IE). sCT administrations were given 4-5 days prior to and during the second study. After a washing-out period of 2 weeks the participants were given 200 IE of sCT at the reverse time of the day 5 days prior to and during the third study. At all timepoints, urinary CrossLaps/Cr exhibited a significant (p < 0.001) circadian rhythm with its zenith in early morning and nadir in late afternoon. Both morning and evening administration of sCT significantly decreased the urinary excretion of CrossLaps/Cr approximately 3-6 h after administration with a subsequent rebound effect. sOC did not exhibit a significant circadian variation and was not affected by the calcitonin. The 24 h mean urinary CrossLaps/Cr and sOC remained unchanged. Both morning and evening sCT significantly decreased the urinary excretion of CrossLaps/Cr 3-6 h after administration, with a rebound effect approximately 12 h later. However, the present study does not indicate that neither evening nor twice-daily administration is superior to morning administration.

Management of osteoporosis and Paget's disease. An appraisal of the risks and benefits of drug treatment

Osteoporosis is a major public health problem occurring primarily among the postmenopausal population. Osteoporosis is a preventable disease, but despite several advances in its prevention, treatment of the established disease to date remains a major challenge to be managed by primary care physicians. Stabilisation of bone mass and prevention of falls are of paramount importance in any therapeutic programme for osteoporotic patients with established vertebral fractures. Drug therapy for osteoporosis can be divided operationally into 2 main categories: those that inhibit bone resorption, and thus reduce bone turnover, and those that stimulate bone formation, exerting an anabolic effect. Therapeutic agents that inhibit bone remodeling would appear to be best suited to those patients with high turnover osteoporosis (about 30%). Included in this category are calcium, vitamin D and its metabolites, gonadal steroids, calcitonin, ipriflavone and bisphosphonates. Although estrogen replacement therapy has been proven to be effective in older females, calcitonin appears to be the treatment of choice for this population since it stabilises or increases bone mass and also has reported analgesic properties. Drugs that stimulate bone remodeling or bone formation would be best suited to patients with low turnover osteoporosis (about 70%). The agent in this class that is widely used is sodium fluoride. New therapies include intermittent injections of synthetic parathyroid hormone, and cyclic bisphosphonates to activate then depress resorption and formation. Any attempts to stabilise the skeleton with any drug regimen must be accompanied by an adequate calcium supply, i.e. 1200 to 1500 mg/day). The theoretical basis of tailoring treatment for osteoporosis to the underlying histology has not yet been fully proven, but there is increasing experimental support to this approach. Drugs that inhibit bone turnover, such as calcitonin, appear to be effective in increasing bone mass for 1.5 to 2 years, about the time it would take to replenish the remodeling space in a patient with high turnover osteoporosis. In contrast, although bone mass appears to increase for as long as 5 years in patients treated with sodium fluoride, there has been no consistent reduction in occurrence of vertebral or hip fractures. Paget' disease of bone is a focal disorder of the skeleton characterised by excessive resorption and subsequently disorganised formation of bone. The aetiology of the disease is unknown. Paget's disease may be mono-ostotic or polyostotic; pain and bone deformities due to enlargement of skeletal segments represent the main clinical aspects. However, in many patients the disease may be asymptomatic.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of intranasal salmon calcitonin therapy on bone mass and bone turnover in early postmenopausal women: a dose-response study

We examine the dose-related effect of intranasal salmon calcitonin (sCT) on the early postmenopausal bone loss and bone turnover; a 2-year, prospective, randomized, double-blind, placebo-controlled study was carried out with 134 healthy women who had passed a natural menopause within 6 months to 3 years. The women were allocated randomly to 2 years of treatment with either 100, 200, or 400 IU of sCT given intranasally or placebo. All groups received a calcium supplement of 500 mg. Twenty-one women left the study before its end and 91 complied with the study criteria throughout. Bone mineral content/density of the distal forearm and lumbar spine and biochemical parameters of bone turnover were measured. Although the measurements after 24 months revealed no significant difference between groups in bone mineral density of the lumbar spine, the average changes over time revealed prevention of bone loss in the groups treated with 200 and 400 IU of sCT (0.2 to -0.6%) and declines of 0.8-1.7% in the groups treated with 100 IU of sCT and placebo (P < 0.05-0.01; within-group testing). There was no dose-related response to sCT but there was a significant difference between the pooled groups treated with 200 plus 400 IU of sCT versus the 100 IU sCT and placebo-treated groups (P = 0.030-0.005). The same difference between groups was seen for biochemical parameters of bone turnover (P = 0.022-0.003). The biochemical parameters of bone turnover revealed decreases of 10-20% (P < 0.001; within group testing) in the groups treated with the two highest sCT doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcitonin and beta-endorphin secretion

Calcitonin is a peptide hormone secreted by the C-cells of the thyroid gland. This hormone mainly acts in preventing bone resorption. Furthermore, calcitonin is involved in other biological actions, and in particular it is able to relieve pain independently of its peripheral effects on bone. Here, we examine the possible mechanisms of calcitonin-induced analgesia, with particular regard to the opioid system involvement. Several studies in animals and in humans demonstrate that calcitonin increases plasma beta-endorphin levels, acting at the hypothalamic and/or at the pituitary level, either directly or indirectly, through monoaminergic neurotransmitters. However, this calcitonin-induced beta-endorphin release has not always been observed. These different results are discussed, and a possible implication of sex and/or calcitonin dose employed has been examined. We conclude that the analgesic effects of calcitonin are multifactorial, and beta-endorphin plays its own specific role.

Rectal salmon calcitonin for the treatment of postmenopausal osteoporosis

In a 2-year study, we examined bone mass and calcium metabolism in 36 elderly women with moderate osteoporosis. The study period comprised 1 year of observation, during which the women received no treatment affecting calcium metabolism, and 1 year of treatment, during which all participants received daily salmon calcitonin (sCT) 100 IU rectally and calcium 500 mg. During the observational period a significant bone loss of 1.5% was seen in the forearm (P less than 0.01), whereas the spinal bone mass was virtually unchanged. After institution of treatment, the bone loss was arrested in the forearm and a significant increase of about 2% was seen in the spine (P less than 0.01). The net effect of treatment revealed a positive outcome in both bone compartments (1.9% and 2.9%, P less than 0.05-0.01). Correspondingly, the parameters of bone turnover (serum alkaline phosphatase, plasma bone Gla protein, and fasting urinary hydroxy-proline/creatinine) did not change during the observational period, but significantly declined, 10-30%, during sCT treatment (P less than 0.01-0.001). Tolerance was generally good, although in one woman, anoscopy revealed irritative changes in the rectal mucosa. We conclude that, given rectally, sCT is well absorbed and well tolerated and that it has a beneficial effect on calcium metabolism in moderately osteoporotic women.

Calcitonin in phantom limb pain: a double-blind study

Salmon calcitonin (s-CT) has been shown to be a valuable analgesic in phantom limb pain (PLP) in several case reports. To evaluate these findings a double-blind crossover comparison of s-CT treatment versus placebo was initiated. Twenty-one out of 161 patients who had undergone major amputations and developed severe PLP 0-7 days after surgery were included in the study. For each patient a matched pair of infusions was prepared containing either 200 IU of s-CT or placebo. Group I (n = 11) was first given s-CT and group II (n = 10) placebo. When PLP reached a level of more than 3 on a numeric analogue scale (NAS) the first infusion was administered. The second infusion (crossover) or more infusions were given when the pain level again exceeded more than 3 on NAS. Using s-CT infusion, PLP was eased from a median of 7 to 4 on NAS in both groups (P less than 0.001), regardless of whether s-CT or placebo was given first. Placebo, however, did not change pain scores (median 7 on NAS, P greater than 0.1). In the s-CT group, but not in the placebo group, 4 individuals remained pain free without a second infusion. Any further treatment was performed with s-CT. One week after the first PLP treatment 19 patients (90%) had pain relief of more than 50%, 16 (76%) were completely pain free, and 15 (71%) never experienced PLP again. One year later 8 out of the 13 surviving patients (62%) still had more than 75% PLP relief. After 2 years PLP exceeded 3 on NAS in 5 individuals (42%), and the remaining 12 patients presented the same PLP as after 1 year. In conclusion, s-CT is a valuable treatment for PLP in the early postoperative period.

Analytical and micropreparative capillary electrophoresis of the peptides from calcitonin

The capillary electrophoresis (CE) of peptide fragments from the tryptic digest of salmon calcitonin and elcatonin has been carried out in H2O- and D2O-based buffer solutions. Analysis in heavy water was found to be superior to that in H2O especially at a pH or pD of 7.93. From a single CE run on elcatonin digest we were also able to harvest three pure cleavage peptides in sufficient quantity to determine each amino acid residue by protein sequencing. The order of elution from CE agreed with that predicted on the basis of net charge calculated for each peptide.

Discontinuous calcitonin treatment of established osteoporosis--effects of withdrawal of treatment

PURPOSE

The purpose of this study was to examine the effects of discontinuous treatments with intranasal salmon calcitonin on bone and calcium metabolism in postmenopausal women and to establish the effects of withdrawing treatment.

PATIENTS AND METHODS

This report presents data from 26 postmenopausal women with established osteoporosis (forearm fracture) 12 months after withdrawal of a 1-year double-blind, placebo-controlled therapy with intranasal calcitonin. The women then resumed treatment with calcitonin 200 IU plus calcium 500 mg daily in an open design for an additional 1-year period. A control group of 19 age-matched women (no forearm fracture) did not receive any treatment.

RESULTS

At the end of the 3 years, the control group had lost significantly more bone in the forearm (single photon absorptiometry) and spine (dual photon absorptiometry) than had the group treated with intranasal calcitonin for 2 years, whereas the group receiving calcitonin for 1 year had intermediate values. During the year of withdrawal, the rate of bone loss was similar in the women who had received calcitonin and those who had received placebo. Calcitonin was especially effective in women with initially high bone turnover and low bone mass. The bone response in the spine could, furthermore, be estimated by the changes in bone turnover.

CONCLUSION

Discontinuous treatment with intranasal calcitonin affects bone and calcium metabolism in established osteoporosis. In women with high-turnover osteoporosis, therapy results in a net gain of bone in both the peripheral and axial skeleton. Response to treatment may be monitored by changes in bone turnover.

The effect of rectal and nasal administration of salmon calcitonin in normal subjects

In order to ascertain the blood levels and the biologic responses obtained after administration of two noninjectable forms of salmon calcitonin (SCT) (i.e., a nasal spray and a suppository), two doses of 200 IU each were administered at 3 hour intervals nasally to 8 normal subjects, and rectally to 9 normal subjects. Five untreated subjects served as controls. All were given a standardized diet for 2 days before the test. Plasma salmon-calcitonin, ionized calcium, phosphate, sodium, proteins, creatinine, and alkaline phosphatase were measured repeatedly after the administration of the drug. Modifications in fractionated urinary calcium, phosphate, sodium, and creatinine excretions (and hydroxyproline for the 8 subjects treated by the nasal spray) were compared with the values measured on the previous day. Plasma concentrations of SCT were found to increase sharply with both routes of administration, the peaks being high and short after rectal administration, low but more sustained after nasal application. Despite these differences, almost similar biologic effects could be demonstrated: transient hypocalcemia, increased calciuria, phosphaturia, and natriuria. Urinary hydroxyproline excretion decreased. Plasma sodium did not increase, whereas it did in the controls. In conclusion, nasal sprays and suppositories of SCT appear to exert the known biologic effects of SCT, and might be favored for long-term treatment in diseases representing indications for calcitonin therapy.

Biochemical response to combination of disodium etidronate with calcitonin in Paget's disease

The biochemical responses to salmon calcitonin (SCT: 100 MRC units thrice weekly) and disodium etidronate (EHDP: 400 mg daily) alone and in combination for 6 months were compared in 72 patients with symptomatic Paget's disease of bone unresponsive to simple analgesic agents. SCT produced a 53% reduction in alkaline phosphatase (AP) and a 38% reduction in 24 h urinary hydroxyproline excretion (HYPRO). The response to EHDP was not significantly different--56% reduction in AP and 48% reduction in HYPRO. Their use in combination produced a significantly greater reduction of 71% in AP (P less than 0.002) and 69% reduction in HYPRO (P less than 0.0001). In those that remained symptomatic with increased disease activity treatment for longer than 6 months had a unpredictable effect and normal bone turnover was rarely achieved. Once therapy was withdrawn AP and HYPRO increased rapidly in those given SCT alone, returning to initial levels within 6 months. More sustained control of disease activity was achieved in those given EHDP either alone or with SCT but the combination retained the advantage obtained during treatment. Combinations of SCT + EHDP may find a place in the treatment of very active Paget's disease.

Effect of (Asu1,7)E-CT, synthetic analogue of eel-calcitonin, on nociceptive transmission

The effect of (Asu1,7)E-CT a deaminodicarba-analogue of the synthetic eel-calcitonin on the nociceptive transmission has been studied in mice. The analogue was intracerebroventricularly (0.0.5-0.01-0.02 U.I./kg) or intravenously (0.02-0.04-0.05 -0.1 U.I./kg) injected. This synthetic derivative of eel-calcitonin increased the antinociceptive effect also after peripheral administration. Moreover, preliminary studies on the time-course of this analogue showed that the dose of 0.1 U.I./kg i.v. injected, was able to elicit antinociceptive effect, already 5 min after the administration.

Paget's disease of bone. An update on management

The essential requirement for effective treatment of Paget's disease of bone is that the characteristic abnormality of bone remodelling is predictably corrected without the occurrence of significant side effects. Although the ideal agent is not currently available, appropriate use of the calcitonins or diphosphonates goes a long way to achieving this goal. Calcitonin (50 to 100 MRC units subcutaneously daily or 3 times weekly) will generally reduce bone turnover by approximately 50% within 6 months. However, very active disease will not be controlled and bone turnover will generally increase once treatment is withdrawn. Calcitonin is without significant side effects, although some patients will develop antibody-mediated resistance to the exogenous calcitonin species. An advantage of calcitonin is that there is radiographic evidence of a return to normal bone remodeling during treatment. Although a number of diphosphonates (now more correctly termed bisphosphonates) are available for experimental use, only the first generation compound, disodium etidronate (EHDP) is commercially available. It too will reduce bone turnover by about 50% within 6 months when given in a dose of 5 mg/kg daily. Unlike calcitonin, it results in a more sustained control of bone turnover while having the additional advantage that it can be given by mouth. Although larger doses are more effective in controlling very active disease, there is a real risk of causing defective bone mineralisation which may result in the development of atraumatic long bone fractures or diffuse bone pains. Combinations of calcitonin and disodium etidronate in conventional dosage seem to result in an additive suppressant effect on bone turnover and may be indicated for more active disease. Advances in treatment are progressing rapidly and it seems likely that in the next few years the introduction of new agents for the control of Paget's disease will more nearly approach the ideal goal of treatment.

Subarachnoid injection of salmon calcitonin does not induce analgesia in rats

It has been proposed that the polypeptide calcitonin (CT) occurs in the central nervous system and may have a neuromodulatory role in endogenous pain relief pathways. However, recent results suggest that CT is not present in the central nervous system. Intrathecal (IT) injection of CT on the lumbar enlargement of rats caused a reversible increase of the hindpaw lick latency in the hot plate test. No analgesia was observed with the vocalization test to electrical stimulation of the tail. In contrast 10 micrograms morphine hydrochloride IT caused analgesia in both tests. It is concluded that IT CT does not cause analgesia, but has a reversible blocking effect on motor responses.

Deterioration of renal bone disease in patients treated with salmon calcitonin

Twelve patients with chronic renal failure and osteitis fibrosa were treated for periods of 1-9 months with thrice-weekly injections of 10-200 iu salmon calcitonin. Treatment had no significant effects on symptoms of bone disease and side effects were common. A transient fall in plasma alkaline phosphatase levels occurred in only three patients, and both plasma alkaline phosphatase and hydroxyproline levels rose in the majority of patients. Radiographic signs of hyperparathyroidism increased in seven of the nine patients treated for longer than 3 months. Paired bone biopsy specimens in nine patients showed significant increases in osteoblast counts, but no changes in the indices of resorption. These treatment-induced changes were reversed when treatment with 1,25-dihydroxyvitamin D3 was substituted for calcitonin. The use of this regimen of salmon calcitonin is not recommended in the long-term management of hyperparathyroid bone disease in chronic renal failure.

Management of fissure fractures in Paget's disease

Forty-five patients with Paget's disease were studied, of whom 25 had fissure fractures affecting the bones of the lower limb. Ten patients treated with salmon calcitonin showed no improvement in their fissure fractures despite reduction in bone turnover. Treatment was effective where bone deformity was improved by traction or intra-medullary nail fixation combined with osteotomy. Surgical treatment should be undertaken in those patients who complain of acute pain at the site of a fissure fracture and who risk completing the fracture. Fissure fractures involving the femoral neck should be fixed even when asymptomatic because of the risk of non-union if they become complete.

Responses to salmon calcitonin in chronic renal failure: relation to histological and biochemical indices of bone turnover

Twenty-one patients with chronic renal failure and bone disease or hypercalcaemia were studied before and following single (twenty patients) or repeated (fourteen patients) intravenous injection of synthetic salmon calcitonin. Significant correlations were noted before treatment between bone surfaces occupied by osteoblasts or osteoclasts and plasma levels of immunoreactive parathyroid hormone, alkaline phosphatase and hydroxyproline. Following a single injection of 2--200 i.u. salmon calcitonin, plasma levels of calcium and phosphate fell for 6--8 h, but rose subsequently to pre-injection levels at 24 h. The magnitude and duration of the hypocalcaemic response was not clearly dose-dependent, but correlated with measured indices of bone cell activity. Repeated administration of calcitonin (10--200 i.u. thrice weekly for up to 2 months) lowered plasma calcium in the majority of patients and restored plasma calcium to normal in four previously hypercalcaemic patients. Mean levels of alkaline phosphatase increased but no significant changes in plasma phosphate, immunoreactive parathyroid hormone and calcitonin, or hydroxyproline occurred. Calcium absorption (six studies) did not change during treatment. We conclude that synthetic salmon calcitonin is an effective short-term inhibitor of bone resorption in patients with chronic renal failure. Its use as a possible treatment for hypercalcaemia and hyperparathyroid bone disease in chronic renal failure is discussed.

Calcitonin and diphosphonate in the treatment of Paget's disease of bone

The ideal treatment for Paget's disease of bone should control turnover irrespective of its initial activity and produce a sustained remission once treatment is withdrawn. Unfortunately, neither the calcitonins nor the diphosphonates currently available entirely fulfil these requirements. Preliminary studies suggest that combinations of calcitonin and EHDP produce significantly better responses than those of the individual agents alone. This proposition is examined critically in terms of the optimum effects achieved with calcitonin and EHDP alone paying particular attention to variables such as disease activity, dose and duration of treatment.

Paget's disease: improvement of spinal cord dysfunction with diphosphonates and calcitonin

The clinical and radiographic features of spinal cord dysfunction secondary to Paget's disease are described. Long-term medical management with the use of the diphosphonates, calcitonins and mithramycin resulted in marked and rapid clinical improvements in 8 of 10 of our own patients. These results are comparable to those seen in 19 other patients previously described in the literature, and are also similar to those obtained by surgical treatment. The recurrence rate and mortality (approximately 10%) of surgical treatment suggest that drug treatment now has a place in the management of paraparesis, particularly when this is of gradual onset. Medical management may also provide a valuable adjunct in those cases where surgery is required (e.g. sudden onset of paraparesis). In patients with cord dysfunction, but without significant anatomical compression of the spinal cord, it is suggested that paraparesis may be caused by a "vascular steal" syndrome, a notion which is supported by the rapidity with which drug-induced remission occurs.

Salmon calcitonin therapy for Paget's disease of bone. The problem of acquired clinical resistance

During the initial months of long-term treatment of Paget's disease of bone with salmon calcitonin, circulating alkaline phosphatase activity and urinary hydroxyproproline excretion usually decrease by about 50%. In 22 of 85 patients these parameters returned to pretreatment levels despite continuous therapy. Nineteen patients who were resistant to salmon calcitonin had salmon calcitonin antibodies in high titer. Human calcitonin has been effective in suppressing disease activity in these patients. The pathogenesis of calcitonin resistance in patients without antibodies is unknown.

Paget's disease of bone

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Functional significance of antibody formation after long-term salmon calcitonin therapy

Twenty patients with Paget's disease were challenged with porcine (PCT) and salmon (SCT) calcitonin before and after 6 months SCT therapy. Acute hypocalcaemia was clearly related to the prevailing rate of bone turnover but responses to PCT showed that treatment had not disturbed this relationship. Although antibodies to SCT developed in eight patients during the period of treatment the acute hypocalcaemic response to SCT was not diminished in relation to bone turnover. It is suggested that antibodies which develop during the course of SCT therapy do not necessarily exert a functionally effective neutralizing action.

Medical staff conference. Paget disease of bone

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Histologic changes in Paget's disease treated with calcitonin

In recent years the use of calcitonin in the medical treatment of Paget's disease of bone has been gaining in popularity. Seventeen patients on long term calcitonin therapy showed objective morphologic evidence of improvement in the quality of bone matrix deposition, in the trabecular organization, and in the parameters used to evaluate the rates of bone turnover. The usefulness of bone biopsy and fine detail radiography of the biopsy core in evaluating the progress of disease and the effects of therapy is discussed. It is concluded that the longer the period of therapy and follow-up, the higher the proportion of patients showing histologic evidence of improvement.

Changes in histologic and biochemical indexes of bone turnover after bilateral nephrectomy in patients on hemodialysis. Evidence for a possible role of endogenous calcitonin

We studied the effects of bilateral nephrectomy on bone metabolism in 27 patients on maintenance hemodialysis. After nephrectomy plasma alkaline phosphatase fell rapidly in 10 patients whose preoperative plasma levels had been higher than normal. This fall was associated with a transient decrease in osteoblast counts of iliac-bone biopsies. A fall in plasma phosphate and a rise in plasma immunoreactive calcitonin also occurred, but calcium and immunoreactive parathyroid hormone levels did not change. Alkaline phosphatase levels remained unchanged in a control group of 17 patients on dialysis who had undergone an operation other than nephrectomy. In 26 nonsurgical patients on dialysis, immunoreactive calcitonin was inversely related to osteoblast counts. Rises in immunoreactive calcitonin may be partly responsible for the transient decreases in bone turnover after bilateral nephrectomy. Low levels of endogenous calcitonin may allow an increase in bone turnover in chronic renal failure.

Evidence that endogenous calcitonin protects against renal bone disease

Plasma concentrations of calcium, phosphate, alkaline phosphatase (A.P.), immunoreactive calcitonin (iC.T.), and immunoreactive parathyroid hormone (iP.T.H.) were measured in fifty-two patients with chronic renal failure on maintenance haemodialysis. On the basis of a bimodal distribution of values for plasma-A.P. the patients were dividied into 2 groups. In those patients with normal A.P. concentratons as well as in twenty-eight normal subjects there was a positive correlation between iP.T.H. and iC.T. which was independent of plasma calcium or phosphate. Patients with increased plasma-A.P. had higher concentrations of iP.T.H., lower concentrations of iC.T., and showed a negative relation between the concentrations of the two hormones. It is suggested that a possible factor in the pathogenesis of renal bone disease is a failure to secrete C.T. in adequate amounts.