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Effects of porcine calcitonin in osteogenesis imperfecta tarda
May, 1972 T h e Journal o[ P E D I A T R I C S
Effects o/porcine
757
calcitonin in osteogenesis
i mperfecta ta rda The effect of the administration of porcine calcitonin to two children with osteogenesis imper[ecta tarda was evaluated by means of calcium and phosphorus balance studies, urinary hydroxyproline excretion, tubular reabsorption of phosphorus, and phosphate clearance before and after administration of parathyroid extract. The balance studies indicated that ealeitonin was effective in causing retention of calcium and phosphorus and decrease in hydroxyproline excretion. These improvements suggest that calcitonin may be of therapeutic value in osteogenesis imperfecta by decreasing bone resorption.
Salvador Castells, M.D., ~ Savlta I n a m d a r , M.D., R i c h a r d K. Baker, M.D., Ph.D., and Stanley Wallaeh, M.D., Brooklyn, N . Y.
O S T E O (3 E N E S I S imperfecta tarda is characterized by frequent fractures, usually occurring after the first year of life, which may cause severe skeletal deformities. Some patients have blue sclerae a n d / o r deafness. The basic defect appears to be a generalized abnormality of connective tissue 1 which is manifested primarily in the skeleton as a disorder of osteoblastic activity, with generalized osteoporosis. Recent studies indicate that calcitonin m a y have beneficial effects in demineralizing bone diseases such as Paget's disease 2, 8 and osteoporosis. 4 T h e From the Departments of Pediatrics and Medicine and the United States Public Health Service Clinical Research Center, State University of New York, Downstate Medical Center. Supported by Grant RR-318 from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health. "~Reprin~ address: Department o'f Pediatrics, State University o[ New York Downstate Medical Center, 450 Ctarkson Ave., Brooklyn, N. Y. 11203.
following report describes the clinical and metabolic effects of porcine calcitonin administered at three different doses to two children who had osteogenesis imperfecta tarda. T h e results indicate that calcitonin had a favorable effect on calcium metabolism in these two patients. CASE REPORTS
Case 1. Patient S. C., a 4~-year-old girl at the time of study, was born after a full-term uneventful pregnancy and normal delivery. The neonatal period was uneventful. At two years of age she had her first fracture, followed by three additional fractures of the lower extremities during a 2 year period. The family history was negative for bone fragility, although several members of the family had blue sclerae. The patient was at the twenty-fifth percentile for height. She had blue sclerae, shortening of the left lower limb, right genuvarus, and asymmetry of the pubic symphysis. Radiologic studies revealed generalized osteoporosis. Hearing by audiometric testing was normal. Vol. 80, No. 5, pp. 757-762
758
CasteIIs et al.
Case 2. Patient M. B., a 3H-year-old boy at the time of study, was born after a full-term uneventful pregnancy and normal delivery. The neonatal period was uneventful. His first fracture, of the left arm, occurred at one year of age. The second fracture, at 1H years of age, involved the right forearm and was followed by a third fracture of the right arm. His father has osteogenesis imperfecta of moderate degree and blue sclerae, and has had approximately 14 fractures. There are no other siblings. The patient was at the fiftieth percentile for height, was free of skeletal deformaties, and had blue sclerae. Radiologic survey of the skeleton revealed generalized osteoporosis. Audiometric testing revealed a mild hearing defect. MATERIALS AND METHODS
At the time of admission both patients were placed on controlled calcium and phosphorus intakes for three weeks before the administration of porcine calcitonin. After one week of dietary adjustment, control metabolic balance measurements were made. After two weeks of control measurements, porcine calcitonin (AL 0831 H.P., Lot No. K423115, Armour Pharmaceutical Company) was started at a dose of 20 Metabolic Research Council ( M R C ) units twice a day for the first week. The lyophilized porcine calcitonin was diluted in 16 per cent gelatin and administered intramuscularly. During the second week of calcitonin therapy, the dose was increased to 40 M R C units twice a day, and during the third week, 80 M R C units was administered twice daily. The seventh week of hospitalization was used for post-treatment studies; no calcitonin was given. The average daily intakes of calcium and phosphorus were determined from chemical analyses of dietary aliquots. Diets, dietary refusals, and stools were homogenized at the end of each 7 day balance period. Twenty-four-hour urine collections were pooled into corresponding 7 day periods. An indirect measurement of parathyroid function was made by the assessmeht of the tubular reabsorption of phosphorus and by the response to the administration of parathyroid extract before and during thera-
The Journal o[ Pediatrics May 1972
py. The day before the administration of parathyroid extract, the tubular reabsorption of phosphorus was measured between 2 P.M. and 6 P.M. The tubular reabsorption of phosphorus (TRP) was calculated by using the formula: % TRP ~ 1(Serum creatinine x urinary phosphorus) x 100.s (Urine creatinine x serum phosphorus) Parathyroid extract was administered intravenously according to the Ellsworth-Howard test, 6 except that a dose of 50 U.S.P. units of parathyroid extract was used. Phosphate clearance was calculated from hourly urinary samples. Serum sodium, potassium, chloride, CO2, alkaline phosphatase, SGOT, total protein, albumin, bilirubin, glucose, and blood urea nitrogen values were determined weekly by the SMA-12-Technicon Autoanalyzer method and were not altered by administration of calcitonin. Serum acid phosphatase, protein electrophoresis, magnesium, and uric acid values did not change significantly during treatment. Weekly complete blood counts, eI~cthrocyte sedimentation rates, and urinalyses were normal before and during treatment. Intradermal skin tests to porcine calcitonin were performed before treatment and were negative. Audiometric testing and radiologic surveys of the skeleton, done before and after treatment, were unaltered by the three 1 week courses of calcitonin. Serum and urinary amino acid values were determined weekly by paper chromatography 7 and were within normal limits. C a l c i u m was measured by automated atomic absorption spectrophotometry, ~ phosphorus by the method of Fiske and Subbarow," and urinary hydroxyproline by the method of Baker and associates. 1~ RESULTS
Both patients had uneventful periods of study and did not have any adverse reactions to porcine calcitonin. T h e results of the calcium balance studies are given in Fig. 1. In Case 1 the average daily intake of calcium was 944 rag. before and 950 rag. during treatment with calcitonin. In
Volume 80 Number 5
Porcine calcitonin in osteogenesis imper[ecta tarda
759
ICALCITONIN DOSE MRC Un t s / B I D.
I~o PLASMA CALCIUM m g / l O 0 ml
,os J
40
BO
I
CALCIUM BALANCE g/DAY PATIENT NO. I
PLASMA CALCIUM m g / I 0 0 me
CALCIUM BALANCE g/DAY
"t
I0 9 1.2]
] I
I I I
I
I
I I I I
1.0-
DIETARY INTAKE ;RINARY
0,8" ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
PATENT NO.2
:::::::.:::
...: :.:+ j:::::::: :::?~:
0.6" 0.4-
!i'~i':i'i!;',!ii~ii:~ii:,!i':i':!':,,i!li'iii::~' :,!,i19',ii:ii! :,i:i':
i
-FECAL
O.2
!iJiiii2iiii2i:ii2iiiii!i!2ii :2 i;iiJi!iliiiiJiiiiiiil}iliiiiiiii21;il}ii;iiiii!;!;ili;i2i!iiiiii21iii iii!i WEEKS OF" OBSERVATION
0 ~'1 2 I 3 4 5 II 6 o-- P R E - - 4 - CALClTONIN -~ POST-
Fig. 1. Calcium balance studies. The amount of dietary calcium was similar in both patients. The areas above the llne of dietary intake indicate negative balances. Both patients were in negative calcium balance during the two weeks preceding administration of calcitonin. During the period of intramuscular administration of calcitonin and a week after, calcium balance became positive due to a decrease in fecal excretion of calcium. Plasma calcium concentrations did not change with administration of calcitonln. Case 2 the average calcium i n t a k e was 951 rag. before a n d 979 rag. d u r i n g t r e a t m e n t . Prior to a d m i n i s t r a t i o n of calcitonin, urin a r y excretion of calcium a v e r a g e d 19.3 rag. a n d 16.6 rag. p e r day, respectively, a n d increased to 38 rag. a n d 39 rag. p e r day, respectively, d u r i n g calcitonin t h e r a p y . Fecal c a l c i u m excretion decreased from 1,053 rag. to 756 rag. p e r d a y in Case 1 a n d from 991 rag. to 741 mg. p e r d a y in Case 2. As a result, their negative c a l c i u m balances of 184 rag. a n d 71 rag. p e r day, respective-
ly, before therapy became positive by 180 rag. and 176 mg. per day, respectively. Plasma calcium concentrations did not change significantly during treatment. Phosphorus balance was measured only in Case 1 (Fig. 2). Plasma phosphorus concentration increased by 0.8 mg. per 100 ml. during the first two weeks of calcitonin therapy but then returned to base-line levels. Urinary phosphorus excretion decreased from 175 nag. to 138 rag. per day and fecal phosphorus decreased from 1,242 mg. to 795 rag.
760
Castells et al.
The journal o[ Pediatrics May 1972
CALC TONIN DOSE MRC Units/B.LO.I r 20 40 80 i PLASMA PHOSPHORUS m g / [ O 0 ml PATIENT
PHOSPHORUS BALANCE g/DAY
i p
i
2.0-
I
I
1.6-
I
f
6 5 4-
1 -I
1.2-
%::::::::::::::::::::::::::::::::::::::::::
I
~..................... URINARY
O~8-
DIETARY
INTAKE
0.4-
WEEKS OF 0 OBSERVATION
,
:)il}iiiii i?}}Jiil};
....
p R E-----z---CA LCITON jN___jp0 S T .
Fig. 2. Phosphorus balance in Case 1. The areas above the line of dietary intake indicate negative balances. During the two weeks preceding cMcitonin administration the patient was in negative phosphorus balance. During the period of intramuscular administration of ealcitonln negative phosphorus baIance persisted, aIthough it was significantly less than in the controI period. Fecal excretion of phosphorus was markedly diminished during administration of calcitonin. The low dietary intake of phosphorus during the study was due to a refusal by the patient of foods high in phosphorus content. Plasma phosphorus concentrations were transiently increased during administration of calcitonin. Table I. Changes in tubular reabsorption of phosphorus and phosphate clearance before and after administration of parathyroid extract during control period and calcitonin treatment
TRP
Control period Phosphate clearance (ral. per rain.)
TRP
Caleitonin treatment Phosphate clearance (ral. per rain.) Pre-PTE I P~
Case
(%)
1
98.7
1.14-+0.11
3.75+0.39
99.2
1.42-+0.20
3.84+0.05
2
92.2
0.59 + 0.13
5.09 + 0.51
99.4
0.54 -+0.03
4.51 + 0.76
Pre-PTE
I P~
(%)
TRP -= tubular reabsorptlon of phosphorus, PTE = pasmhyroid extract. *50 U.S.P. of parathyroid extract (Lilly) was given intravenously at 10 A.M. over a 5 minute period.
per day during treatment with calcitonin. As a result, the negative phosphorus balance of 894 mg. per day before calcitonin administration was reduced to 414 mg. per day. In both patients the observed changes in calcium and phosphorus balance were maintained during the post-treatment week. In Case 1, mean urinary hydroxyproline excretion before calcitonin therapy was 66.5 + 3.0 (S.E.M.) mg. per 24 hours and was unchanged by administration of calcitonin (71.4 + 1.8 mg. per 24 hours). In Case 2, mean urinary hydroxyproline excretion before giving calcitonin was 143 + 23.4 rag. per 24 hours and was significantly reduced to 77.2 _+ 2.5 rag. per 25 hours (p < 0.05)
during treatment. The tubular reabsorptions of phosphorus before treatment were 98.7 per cent and 92.2 per cent, respectively. During calcitonin therapy the tubular resorptions of phosphorus were 99.2 per cent and 99.4 per cent (Table I ) . The patients had similar increases in phosphate clearance after the administration of parathyroid extract before and during administration of calcitonin (Table I). DISCUSSION The present data indicate that the administration of porcine calcitonin was effective in causing retention of calcium in two patients with osetogenesis imperfecta
Volume 80 Number 5
Porcine calcitonin in osteogenesis imper/ecta tarda
tarda and in improving phosphorus conservation in one patient. Fecal calcium decreased markedly whereas urinary calcium increased slightly. Thus calcitonin increased the intestinal absorption of calcium and the retention of calcium by the skeleton. These changes are similar to the reported effects of calcitonin in Paget's disease 2, 3 and in osteoporosis. * In the single phosphorus balance study, the low dietary intake of phosphorus reflected the patient's refusal of foods high in phosphorus content and could have contributed to the negative phosphorus balance. The increased intestinal absorption of phosphorus was accompanied by a transient increase in the plasma phosphorus level. Improved intestinal absorption of phosphorus has also been seen in patients with Paget's disease receiving calcitonin. 2, 3 The changes in calcium and phosphorus balance studies were similar d u r i n g the three weeks of treatment even though the porcine calcitonin was given in increasing doses. These findings suggest that a maximal pharmacologic effect of calcitonin was achieved at the lowest dose used, 40 M R C units daily. The principal mode of action of calcitonin at the cellular level is an inhibition of bone resorption n, 42; the degree of inhibition may be quantitatively dependent upon the existing rate of bone resorption? a Urinary excretion of hydroxyproline, which is considered to be an index of bone resorption, is increased in most patients with osteogenesis imperfecta, 14 suggesting that the osteoporosis of osteogenesis imperfecta may in part be secondary to an increase in bone resorption. However, an inefficient production of bone with an increased discharge of large peptides containing hydroxyproline might also contribute to the increased excretion of hydroxyproline. Treatment with porcine calcitonin resulted in a marked decrease in urinary hydroxyproline in Case 2. In Case 1, baseline urinary excretion o f hydroxyproline was less than in Case 2, which might explain the lack of effect of calcitonin. In the patients with Paget's disease, the greatest decreases in urinary hydroxyproline excretion occur in the patients with the highest
76 1
base-line levels before administration of calcitonin. 2 A single intravenous injection of calcitonin frequently induces phosphaturia, possibly as a result of an increased secretion of parathyroid hormone? 6 An irregular phosphaturia has also been observed during chronic administration of calcitonin in patients with Paget's disease? In our two patients with osteogenesis imperfecta, there was no indirect evidence for hypersecretion of parathyroid hormone secondary to calcitonin on the basis of the urinary phosphorus excretion and the renal responses to parathyroid extract. The accumulated data suggest that calcitonin m a y be of therapeutic value in osteogenesis imperfecta by decreasing bone resorption. Long-term studies are warranted on the basis of these acute studies using porcine calcitonin. The authors would like to thank Dr. James B. Lesh of the Clinical Research Department of Armour Pharmaceutical Company for supplying the porcine calcitonin and Dr. A. S. Ridolfo of the Clinical Research Division of Eli Lilly and Company for supplying the parathyroid extract. The dedicated cooperation of the nurses and dietitians at the United States Public Health Service Clinical Research Center is greatly appreciated. REFERENCES
1. Stevenson, C. J., Bottoms, 2., and Shuster, S. : Skin collagen in osteogenesis imperfecta, Lancet 1: 860, 1970. 2. Bell, N. H., Avery, S., and Johnston, C. C., Jr.: Effects of calcitonin in Paget's disease and polyostotic fibrosis dysplasia, J. Clin. Endocrinol. Metab. 31: 283, 1970. 3. Shal, F., Baker, R. K., and Wallach, S.: The clinical and metabolic effects of porcine calcitonin on Paget's disease of bone, J. Clin. Invest. 50: 1927, 1971. 4. Canlggia, A., Gennarl, C., Bencinl, M., Cesari, L., and Borrello, O.: Calcium metabolism and .7 calcium Kinetics before and after long-term thyrocalcitonin treatment in senile osteoporosis, Clin. Sci. 38: 397, 1970. 5. Hills, A. G., and Burr, J. M.: Analysls of the phosphorus reabsorption index: Theoretical and practical implications, J. Clin. Endocrinol. Metab. 17: 1472, 1957. 6. Ellsworth, R., and Howard, J. 2.: Studies on the physiology of the parathyroid glands. VII. Some responses of normal human Kid-
762
7.
8.
9. 10. 11.
CasteIls et aZ.
neys and blood to intravenous parathyroid extract, Bull. Hopkins Hosp. 55: 296, 1934. Efron, M. L., Young, D., Moser, H. W., and Mac Cready, R. A.: A simple chroraatographic screening test for the detection of disorders of amino acid metabolism, N. Engl. J. Med. 270: 1378, 1964. Posner, A., Francis, H., and Baker, R. K.: Microdetermlnation of calcium and magnesium by automated atomic absorption spectrophotometry. In press. Fiske, C. H., and Subbarow, Y.: The colorimetric determination of phosphorus, J. Biol. Chem. 66: 375, 1925. Baker, R. K., Francis, H., and Posner, A.: An automated method for the estimation of hydroxyproline, Clin. Chem. 15: 817, 1969. Wallach, S., Chausmer, A., Mittleman, R., and Dimich, A.: In vivo inhibition of bone
The journal o[ Pediatrics May 1972
I2. 13.
14.
15.
resorption by thyrocalcitonln, Endocrinology 80: 61, 1967. Ports, J. T., Jr.: Recent advances in thyrocalcitonin research, Fed. Proc. 29" 1200, 1970. Mittleman, R., Wallach, S., Chausmer, A., and BelIavia, J.: Interaction of thyrocalcitonin and vitamin D on bone resorption in Calcitonin, (Proceedings of the Symposium on Thyrocalcitonin and the C Ceils, 17-20, July, London, 1967), London, 1968, William Helnemann, Ltd., pp. 276-281. Langness, V., and Behnke, H.: Die hydroxyprolinausschei: dung im Urin bei der osteogenesis imperfecta, Klin. Wochenschr. 44: 1294, 1966. Caniggia, A., and Gennarl, C.: Azione della tiroealcitonina nell'nomo, Minerva Med. 59: 279, 1968.
Effects o/porcine
757
calcitonin in osteogenesis
i mperfecta ta rda The effect of the administration of porcine calcitonin to two children with osteogenesis imper[ecta tarda was evaluated by means of calcium and phosphorus balance studies, urinary hydroxyproline excretion, tubular reabsorption of phosphorus, and phosphate clearance before and after administration of parathyroid extract. The balance studies indicated that ealeitonin was effective in causing retention of calcium and phosphorus and decrease in hydroxyproline excretion. These improvements suggest that calcitonin may be of therapeutic value in osteogenesis imperfecta by decreasing bone resorption.
Salvador Castells, M.D., ~ Savlta I n a m d a r , M.D., R i c h a r d K. Baker, M.D., Ph.D., and Stanley Wallaeh, M.D., Brooklyn, N . Y.
O S T E O (3 E N E S I S imperfecta tarda is characterized by frequent fractures, usually occurring after the first year of life, which may cause severe skeletal deformities. Some patients have blue sclerae a n d / o r deafness. The basic defect appears to be a generalized abnormality of connective tissue 1 which is manifested primarily in the skeleton as a disorder of osteoblastic activity, with generalized osteoporosis. Recent studies indicate that calcitonin m a y have beneficial effects in demineralizing bone diseases such as Paget's disease 2, 8 and osteoporosis. 4 T h e From the Departments of Pediatrics and Medicine and the United States Public Health Service Clinical Research Center, State University of New York, Downstate Medical Center. Supported by Grant RR-318 from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health. "~Reprin~ address: Department o'f Pediatrics, State University o[ New York Downstate Medical Center, 450 Ctarkson Ave., Brooklyn, N. Y. 11203.
following report describes the clinical and metabolic effects of porcine calcitonin administered at three different doses to two children who had osteogenesis imperfecta tarda. T h e results indicate that calcitonin had a favorable effect on calcium metabolism in these two patients. CASE REPORTS
Case 1. Patient S. C., a 4~-year-old girl at the time of study, was born after a full-term uneventful pregnancy and normal delivery. The neonatal period was uneventful. At two years of age she had her first fracture, followed by three additional fractures of the lower extremities during a 2 year period. The family history was negative for bone fragility, although several members of the family had blue sclerae. The patient was at the twenty-fifth percentile for height. She had blue sclerae, shortening of the left lower limb, right genuvarus, and asymmetry of the pubic symphysis. Radiologic studies revealed generalized osteoporosis. Hearing by audiometric testing was normal. Vol. 80, No. 5, pp. 757-762
758
CasteIIs et al.
Case 2. Patient M. B., a 3H-year-old boy at the time of study, was born after a full-term uneventful pregnancy and normal delivery. The neonatal period was uneventful. His first fracture, of the left arm, occurred at one year of age. The second fracture, at 1H years of age, involved the right forearm and was followed by a third fracture of the right arm. His father has osteogenesis imperfecta of moderate degree and blue sclerae, and has had approximately 14 fractures. There are no other siblings. The patient was at the fiftieth percentile for height, was free of skeletal deformaties, and had blue sclerae. Radiologic survey of the skeleton revealed generalized osteoporosis. Audiometric testing revealed a mild hearing defect. MATERIALS AND METHODS
At the time of admission both patients were placed on controlled calcium and phosphorus intakes for three weeks before the administration of porcine calcitonin. After one week of dietary adjustment, control metabolic balance measurements were made. After two weeks of control measurements, porcine calcitonin (AL 0831 H.P., Lot No. K423115, Armour Pharmaceutical Company) was started at a dose of 20 Metabolic Research Council ( M R C ) units twice a day for the first week. The lyophilized porcine calcitonin was diluted in 16 per cent gelatin and administered intramuscularly. During the second week of calcitonin therapy, the dose was increased to 40 M R C units twice a day, and during the third week, 80 M R C units was administered twice daily. The seventh week of hospitalization was used for post-treatment studies; no calcitonin was given. The average daily intakes of calcium and phosphorus were determined from chemical analyses of dietary aliquots. Diets, dietary refusals, and stools were homogenized at the end of each 7 day balance period. Twenty-four-hour urine collections were pooled into corresponding 7 day periods. An indirect measurement of parathyroid function was made by the assessmeht of the tubular reabsorption of phosphorus and by the response to the administration of parathyroid extract before and during thera-
The Journal o[ Pediatrics May 1972
py. The day before the administration of parathyroid extract, the tubular reabsorption of phosphorus was measured between 2 P.M. and 6 P.M. The tubular reabsorption of phosphorus (TRP) was calculated by using the formula: % TRP ~ 1(Serum creatinine x urinary phosphorus) x 100.s (Urine creatinine x serum phosphorus) Parathyroid extract was administered intravenously according to the Ellsworth-Howard test, 6 except that a dose of 50 U.S.P. units of parathyroid extract was used. Phosphate clearance was calculated from hourly urinary samples. Serum sodium, potassium, chloride, CO2, alkaline phosphatase, SGOT, total protein, albumin, bilirubin, glucose, and blood urea nitrogen values were determined weekly by the SMA-12-Technicon Autoanalyzer method and were not altered by administration of calcitonin. Serum acid phosphatase, protein electrophoresis, magnesium, and uric acid values did not change significantly during treatment. Weekly complete blood counts, eI~cthrocyte sedimentation rates, and urinalyses were normal before and during treatment. Intradermal skin tests to porcine calcitonin were performed before treatment and were negative. Audiometric testing and radiologic surveys of the skeleton, done before and after treatment, were unaltered by the three 1 week courses of calcitonin. Serum and urinary amino acid values were determined weekly by paper chromatography 7 and were within normal limits. C a l c i u m was measured by automated atomic absorption spectrophotometry, ~ phosphorus by the method of Fiske and Subbarow," and urinary hydroxyproline by the method of Baker and associates. 1~ RESULTS
Both patients had uneventful periods of study and did not have any adverse reactions to porcine calcitonin. T h e results of the calcium balance studies are given in Fig. 1. In Case 1 the average daily intake of calcium was 944 rag. before and 950 rag. during treatment with calcitonin. In
Volume 80 Number 5
Porcine calcitonin in osteogenesis imper[ecta tarda
759
ICALCITONIN DOSE MRC Un t s / B I D.
I~o PLASMA CALCIUM m g / l O 0 ml
,os J
40
BO
I
CALCIUM BALANCE g/DAY PATIENT NO. I
PLASMA CALCIUM m g / I 0 0 me
CALCIUM BALANCE g/DAY
"t
I0 9 1.2]
] I
I I I
I
I
I I I I
1.0-
DIETARY INTAKE ;RINARY
0,8" ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
PATENT NO.2
:::::::.:::
...: :.:+ j:::::::: :::?~:
0.6" 0.4-
!i'~i':i'i!;',!ii~ii:~ii:,!i':i':!':,,i!li'iii::~' :,!,i19',ii:ii! :,i:i':
i
-FECAL
O.2
!iJiiii2iiii2i:ii2iiiii!i!2ii :2 i;iiJi!iliiiiJiiiiiiil}iliiiiiiii21;il}ii;iiiii!;!;ili;i2i!iiiiii21iii iii!i WEEKS OF" OBSERVATION
0 ~'1 2 I 3 4 5 II 6 o-- P R E - - 4 - CALClTONIN -~ POST-
Fig. 1. Calcium balance studies. The amount of dietary calcium was similar in both patients. The areas above the llne of dietary intake indicate negative balances. Both patients were in negative calcium balance during the two weeks preceding administration of calcitonin. During the period of intramuscular administration of calcitonin and a week after, calcium balance became positive due to a decrease in fecal excretion of calcium. Plasma calcium concentrations did not change with administration of calcitonln. Case 2 the average calcium i n t a k e was 951 rag. before a n d 979 rag. d u r i n g t r e a t m e n t . Prior to a d m i n i s t r a t i o n of calcitonin, urin a r y excretion of calcium a v e r a g e d 19.3 rag. a n d 16.6 rag. p e r day, respectively, a n d increased to 38 rag. a n d 39 rag. p e r day, respectively, d u r i n g calcitonin t h e r a p y . Fecal c a l c i u m excretion decreased from 1,053 rag. to 756 rag. p e r d a y in Case 1 a n d from 991 rag. to 741 mg. p e r d a y in Case 2. As a result, their negative c a l c i u m balances of 184 rag. a n d 71 rag. p e r day, respective-
ly, before therapy became positive by 180 rag. and 176 mg. per day, respectively. Plasma calcium concentrations did not change significantly during treatment. Phosphorus balance was measured only in Case 1 (Fig. 2). Plasma phosphorus concentration increased by 0.8 mg. per 100 ml. during the first two weeks of calcitonin therapy but then returned to base-line levels. Urinary phosphorus excretion decreased from 175 nag. to 138 rag. per day and fecal phosphorus decreased from 1,242 mg. to 795 rag.
760
Castells et al.
The journal o[ Pediatrics May 1972
CALC TONIN DOSE MRC Units/B.LO.I r 20 40 80 i PLASMA PHOSPHORUS m g / [ O 0 ml PATIENT
PHOSPHORUS BALANCE g/DAY
i p
i
2.0-
I
I
1.6-
I
f
6 5 4-
1 -I
1.2-
%::::::::::::::::::::::::::::::::::::::::::
I
~..................... URINARY
O~8-
DIETARY
INTAKE
0.4-
WEEKS OF 0 OBSERVATION
,
:)il}iiiii i?}}Jiil};
....
p R E-----z---CA LCITON jN___jp0 S T .
Fig. 2. Phosphorus balance in Case 1. The areas above the line of dietary intake indicate negative balances. During the two weeks preceding cMcitonin administration the patient was in negative phosphorus balance. During the period of intramuscular administration of ealcitonln negative phosphorus baIance persisted, aIthough it was significantly less than in the controI period. Fecal excretion of phosphorus was markedly diminished during administration of calcitonin. The low dietary intake of phosphorus during the study was due to a refusal by the patient of foods high in phosphorus content. Plasma phosphorus concentrations were transiently increased during administration of calcitonin. Table I. Changes in tubular reabsorption of phosphorus and phosphate clearance before and after administration of parathyroid extract during control period and calcitonin treatment
TRP
Control period Phosphate clearance (ral. per rain.)
TRP
Caleitonin treatment Phosphate clearance (ral. per rain.) Pre-PTE I P~
Case
(%)
1
98.7
1.14-+0.11
3.75+0.39
99.2
1.42-+0.20
3.84+0.05
2
92.2
0.59 + 0.13
5.09 + 0.51
99.4
0.54 -+0.03
4.51 + 0.76
Pre-PTE
I P~
(%)
TRP -= tubular reabsorptlon of phosphorus, PTE = pasmhyroid extract. *50 U.S.P. of parathyroid extract (Lilly) was given intravenously at 10 A.M. over a 5 minute period.
per day during treatment with calcitonin. As a result, the negative phosphorus balance of 894 mg. per day before calcitonin administration was reduced to 414 mg. per day. In both patients the observed changes in calcium and phosphorus balance were maintained during the post-treatment week. In Case 1, mean urinary hydroxyproline excretion before calcitonin therapy was 66.5 + 3.0 (S.E.M.) mg. per 24 hours and was unchanged by administration of calcitonin (71.4 + 1.8 mg. per 24 hours). In Case 2, mean urinary hydroxyproline excretion before giving calcitonin was 143 + 23.4 rag. per 24 hours and was significantly reduced to 77.2 _+ 2.5 rag. per 25 hours (p < 0.05)
during treatment. The tubular reabsorptions of phosphorus before treatment were 98.7 per cent and 92.2 per cent, respectively. During calcitonin therapy the tubular resorptions of phosphorus were 99.2 per cent and 99.4 per cent (Table I ) . The patients had similar increases in phosphate clearance after the administration of parathyroid extract before and during administration of calcitonin (Table I). DISCUSSION The present data indicate that the administration of porcine calcitonin was effective in causing retention of calcium in two patients with osetogenesis imperfecta
Volume 80 Number 5
Porcine calcitonin in osteogenesis imper/ecta tarda
tarda and in improving phosphorus conservation in one patient. Fecal calcium decreased markedly whereas urinary calcium increased slightly. Thus calcitonin increased the intestinal absorption of calcium and the retention of calcium by the skeleton. These changes are similar to the reported effects of calcitonin in Paget's disease 2, 3 and in osteoporosis. * In the single phosphorus balance study, the low dietary intake of phosphorus reflected the patient's refusal of foods high in phosphorus content and could have contributed to the negative phosphorus balance. The increased intestinal absorption of phosphorus was accompanied by a transient increase in the plasma phosphorus level. Improved intestinal absorption of phosphorus has also been seen in patients with Paget's disease receiving calcitonin. 2, 3 The changes in calcium and phosphorus balance studies were similar d u r i n g the three weeks of treatment even though the porcine calcitonin was given in increasing doses. These findings suggest that a maximal pharmacologic effect of calcitonin was achieved at the lowest dose used, 40 M R C units daily. The principal mode of action of calcitonin at the cellular level is an inhibition of bone resorption n, 42; the degree of inhibition may be quantitatively dependent upon the existing rate of bone resorption? a Urinary excretion of hydroxyproline, which is considered to be an index of bone resorption, is increased in most patients with osteogenesis imperfecta, 14 suggesting that the osteoporosis of osteogenesis imperfecta may in part be secondary to an increase in bone resorption. However, an inefficient production of bone with an increased discharge of large peptides containing hydroxyproline might also contribute to the increased excretion of hydroxyproline. Treatment with porcine calcitonin resulted in a marked decrease in urinary hydroxyproline in Case 2. In Case 1, baseline urinary excretion o f hydroxyproline was less than in Case 2, which might explain the lack of effect of calcitonin. In the patients with Paget's disease, the greatest decreases in urinary hydroxyproline excretion occur in the patients with the highest
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base-line levels before administration of calcitonin. 2 A single intravenous injection of calcitonin frequently induces phosphaturia, possibly as a result of an increased secretion of parathyroid hormone? 6 An irregular phosphaturia has also been observed during chronic administration of calcitonin in patients with Paget's disease? In our two patients with osteogenesis imperfecta, there was no indirect evidence for hypersecretion of parathyroid hormone secondary to calcitonin on the basis of the urinary phosphorus excretion and the renal responses to parathyroid extract. The accumulated data suggest that calcitonin m a y be of therapeutic value in osteogenesis imperfecta by decreasing bone resorption. Long-term studies are warranted on the basis of these acute studies using porcine calcitonin. The authors would like to thank Dr. James B. Lesh of the Clinical Research Department of Armour Pharmaceutical Company for supplying the porcine calcitonin and Dr. A. S. Ridolfo of the Clinical Research Division of Eli Lilly and Company for supplying the parathyroid extract. The dedicated cooperation of the nurses and dietitians at the United States Public Health Service Clinical Research Center is greatly appreciated. REFERENCES
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