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The functional contribution of marrow stromal cell population to the bone deficit in the ovariectomized rat—effect of dihydrotachysterol
Abstracts
414
THE EFFECTS OF CHRONIC INSULIN DEFICIENCY BONE MINERALIZATION AND MECHANICS T. Einhorn, M. Beyer,’ V. Vigorita4
ON
A. Boskey,* C. Gundberg,3
‘State Univ. N.Y., Brooklyn USA, ‘Hosp. Special Surgery, New York City USA, 3Childrens Hosp. Med. Ctr., Boston USA, 4Lutheran Hospital, Brooklyn USA Recent
reports
have documented
osteopenia,
impaired In human diabetes and in streptozotocin(STZ)-induced diabetes in rats. We performed this study in order to examine the long-term effects of these metabolic changes on the mineral and mechanical properties of bone. Sixteen male Lewis rats were divided into 2 groups. Eight served as controls while 8 were made hyperglycemic with 65 mgikg of IV STZ. The rats ate a normal diet and drank tap water ad libitum. After 12 mos., the rats were doubly tetracycline labeled and subsequently killed. Sera was collected for blood glucose and creatinine. The left femora were subjected to mechanical torsion testing to failure. The right femora were subjected to static and dynamic histomorphometry. The metaphyses and diaphyses of the tibiae were analyzed as follows: X-ray diffraction was used to determine crystallite size and perfection. Ash weights and Ca/P of the ash were performed. Bone osteocalcin and Gla protein determinations were accomplished using RIA and automated amino acid analysis, respectively. The results showed that STZ-Rx rats were hyperglycemrc but not uremic since creatinine levels were normal. The bone changes were, therefore, due to hyperglycemra or insulinopenia but not to a secondary effect from renal failure. Mechanically, STZ-Rx bones showed decreased torsional strength, energy absorptive capacity and angular deformation but increased stiffness. Crystallite perfection. CaiP and % ash was reduced in the metaphyses but increased in the diaphyses explaining how stiffness was increased in femoral diaphyseal bone. Neither histomorphometric measurements, osteocalcin levels nor Gla proteins differed between groups. These findings suggest that chronic insulin deficiency produces alterations in bone mechanics and mineral parameters which differ between the metaphysis and diaphysis, and are not related to changes in bone turnover.
1,25(OH),D, synthesis and hyperparathyroidism
24,2S(OH)*D, ENHANCES THE CALCEMIC 1 ,25(OH)2D, IN INTACT AND PTX RATS Hanna Wald, Yossi Traves, Mordecai Nephrology Services, Hadassah Jerusalem, Israel
EFFECT OF
M. Popovtzer
University Hospital,
The effect of 24,25(OH),D, on 1,25(0H),D,-induced hypercalcemia was studied in normal and PTX rats. Serum (S) and urinary Ca (U,,V) were measured in a. controls, b. rats receiving 1 ,25(OH),D3, c rats receiving 24,25(OH),D,, and d. rats receiving 1,25(OH),D, + 24,25(OH)*D3. The basal So, In controls was 5.8 ? 0.07 and in the PTX rats it was 3.7 t 0.26 mEq/L. After 24 h So, increased equally with 1,25(OH),D, and with 1,25(OH),D, + 24,25(OH),D3, while 24,25(OH),D, alone did not change Sea in intact and PTX rats. Uc,V after 24 h with 1,25(OH),D3 + 24,25(OH),D3 increased less than with 1,25(0H)*D, alone (p < 0.025). After 5 days of 1,25(OH)2D, Sea rose from 5.1 2 0.15 to 6.29 2 0.08 in
from the Calcified Tissues Workshop
intact and from 4.02 + 0.35 to 6.33 ? 0.15 in PTX rats, whereas 1,25(OH),D, + 24,25(OH),D, affected a greater Increase in Sca up to 6.63 f 0.09 in the intact (p < 0.01) and up to 6.29 2 0.14 in the PTX rats (p < 0.001). 24,25(OH)*D, alone did not change Sca. After 5 days Uo,V rose similarly with 1,25(OH),D3 and with 1,25(OH),D, + 24,25(OH),D, in intact and tended to decrease (although not significant) with 1,25(OH)*D, + 24,25(OH),D, compared to 1,25(OH),D3 alone in the PTX rats. After IO days of 1,25(OH),D, Sea was 6.17 + 0.15 in intact and 6.04 -+ 0.14 in the PTX while with the combination Sea rose to 6.74 & 0.2 (p < 0.025) in intact and to 7.24 I 0.15 (p < 0.001) In PTX rats; 24,25(OH),D, alone did not change Sea in intact and slightly decreased Sea in PTX rats. After IO days Uc,V was significantly lower with 1,25(OH),D, + 24,25(OH),D, compared to 1,25(OH),D3 alone (p < 0.001) in the PTX group. These results show that 1. combined administration of 1,25(OH),D3 + 24,25(OH)*D3 enhances the hypercalcemic response to 1 ,25(OH)*D3 without a parallel increase in Uo,V, 2. it is suggested that the effect of 24,25(OH),D, on Sca, at least partly, may result from its hypocalciuric effect, and 3. these alterations are independent of parathyroid hormone.
THE FUNCTIONAL CONTRIBUTION OF MARROW STROMAL CELL POPULATION TO THE BONE DEFICIT IN THE OVARIECTOMIZED RAT-EFFECT OF DIHYDROTACHYSTEROL C. Tabuchi, D.J. Simmons, A. Fausto, J.E. Russell. I. Binderman, L.V. Avioli Jewish Hospital and Washington Univ., fsrael
Univ., St Louis; Tel AVIV
A radrologrc scoring system indicated that female rats show thinner than normal femoral cortices 6 mos postovanectomy. We tested the hypothesis that this poor osteogenic record was due in-part to a deficit in the numbers and/or proliferative and osteogenic potential of marrow (osteoprogenitor) stromal cells. In vitro clonal growth (FCFUs) of stromal cells from ovariectomized (OVX) rats was significantly impaired. Yet, in vivo, cells from Sham-op and OVX’d rats proved to have equal osteogenic potential when implanted in millipore diffusion chambers, or implanted i.m in association with an osteogenic demineralized bone matrix ( = Composite Graft). The in vitro proliferative potential and clonal growth of marrow stromal cells from OVX’d rats was significantly enhanced by long-term Dihydrotachysterol (DHT)-treatment (6 mos), as was their osteogenic expression in millipore chambers and response to an osteoinductive DBM. The observation that the in vivo osteogenic performance of OVX’d marrow stromal cells was normal at sites away from bone suggests that stromal cell numbers are normal, but that the mechanisms leading to osteopenia may involve an abnormality in cell-matrix interactions.
IDIOPATHIC HYPERCALCIURIA (I.H.) AND HEREDITARY HYPOPHOSPHATEMIA RICKETS (H.H.R.H.)-TWO PHENOTYPICAL EXPRESSIONS A COMMON GENETIC DEFECT M. Treder, D. Modai, U. Shaked, R. Samuel, R. Arie, A. Halabe, Y. Maor, J. Weisgarten, Z. Averbukh, S Edelstein, U.A. Liberman
OF
414
THE EFFECTS OF CHRONIC INSULIN DEFICIENCY BONE MINERALIZATION AND MECHANICS T. Einhorn, M. Beyer,’ V. Vigorita4
ON
A. Boskey,* C. Gundberg,3
‘State Univ. N.Y., Brooklyn USA, ‘Hosp. Special Surgery, New York City USA, 3Childrens Hosp. Med. Ctr., Boston USA, 4Lutheran Hospital, Brooklyn USA Recent
reports
have documented
osteopenia,
impaired In human diabetes and in streptozotocin(STZ)-induced diabetes in rats. We performed this study in order to examine the long-term effects of these metabolic changes on the mineral and mechanical properties of bone. Sixteen male Lewis rats were divided into 2 groups. Eight served as controls while 8 were made hyperglycemic with 65 mgikg of IV STZ. The rats ate a normal diet and drank tap water ad libitum. After 12 mos., the rats were doubly tetracycline labeled and subsequently killed. Sera was collected for blood glucose and creatinine. The left femora were subjected to mechanical torsion testing to failure. The right femora were subjected to static and dynamic histomorphometry. The metaphyses and diaphyses of the tibiae were analyzed as follows: X-ray diffraction was used to determine crystallite size and perfection. Ash weights and Ca/P of the ash were performed. Bone osteocalcin and Gla protein determinations were accomplished using RIA and automated amino acid analysis, respectively. The results showed that STZ-Rx rats were hyperglycemrc but not uremic since creatinine levels were normal. The bone changes were, therefore, due to hyperglycemra or insulinopenia but not to a secondary effect from renal failure. Mechanically, STZ-Rx bones showed decreased torsional strength, energy absorptive capacity and angular deformation but increased stiffness. Crystallite perfection. CaiP and % ash was reduced in the metaphyses but increased in the diaphyses explaining how stiffness was increased in femoral diaphyseal bone. Neither histomorphometric measurements, osteocalcin levels nor Gla proteins differed between groups. These findings suggest that chronic insulin deficiency produces alterations in bone mechanics and mineral parameters which differ between the metaphysis and diaphysis, and are not related to changes in bone turnover.
1,25(OH),D, synthesis and hyperparathyroidism
24,2S(OH)*D, ENHANCES THE CALCEMIC 1 ,25(OH)2D, IN INTACT AND PTX RATS Hanna Wald, Yossi Traves, Mordecai Nephrology Services, Hadassah Jerusalem, Israel
EFFECT OF
M. Popovtzer
University Hospital,
The effect of 24,25(OH),D, on 1,25(0H),D,-induced hypercalcemia was studied in normal and PTX rats. Serum (S) and urinary Ca (U,,V) were measured in a. controls, b. rats receiving 1 ,25(OH),D3, c rats receiving 24,25(OH),D,, and d. rats receiving 1,25(OH),D, + 24,25(OH)*D3. The basal So, In controls was 5.8 ? 0.07 and in the PTX rats it was 3.7 t 0.26 mEq/L. After 24 h So, increased equally with 1,25(OH),D, and with 1,25(OH),D, + 24,25(OH),D3, while 24,25(OH),D, alone did not change Sea in intact and PTX rats. Uc,V after 24 h with 1,25(OH),D3 + 24,25(OH),D3 increased less than with 1,25(0H)*D, alone (p < 0.025). After 5 days of 1,25(OH)2D, Sea rose from 5.1 2 0.15 to 6.29 2 0.08 in
from the Calcified Tissues Workshop
intact and from 4.02 + 0.35 to 6.33 ? 0.15 in PTX rats, whereas 1,25(OH),D, + 24,25(OH),D, affected a greater Increase in Sca up to 6.63 f 0.09 in the intact (p < 0.01) and up to 6.29 2 0.14 in the PTX rats (p < 0.001). 24,25(OH)*D, alone did not change Sca. After 5 days Uo,V rose similarly with 1,25(OH),D3 and with 1,25(OH),D, + 24,25(OH),D, in intact and tended to decrease (although not significant) with 1,25(OH)*D, + 24,25(OH),D, compared to 1,25(OH),D3 alone in the PTX rats. After IO days of 1,25(OH),D, Sea was 6.17 + 0.15 in intact and 6.04 -+ 0.14 in the PTX while with the combination Sea rose to 6.74 & 0.2 (p < 0.025) in intact and to 7.24 I 0.15 (p < 0.001) In PTX rats; 24,25(OH),D, alone did not change Sea in intact and slightly decreased Sea in PTX rats. After IO days Uc,V was significantly lower with 1,25(OH),D, + 24,25(OH),D, compared to 1,25(OH),D3 alone (p < 0.001) in the PTX group. These results show that 1. combined administration of 1,25(OH),D3 + 24,25(OH)*D3 enhances the hypercalcemic response to 1 ,25(OH)*D3 without a parallel increase in Uo,V, 2. it is suggested that the effect of 24,25(OH),D, on Sca, at least partly, may result from its hypocalciuric effect, and 3. these alterations are independent of parathyroid hormone.
THE FUNCTIONAL CONTRIBUTION OF MARROW STROMAL CELL POPULATION TO THE BONE DEFICIT IN THE OVARIECTOMIZED RAT-EFFECT OF DIHYDROTACHYSTEROL C. Tabuchi, D.J. Simmons, A. Fausto, J.E. Russell. I. Binderman, L.V. Avioli Jewish Hospital and Washington Univ., fsrael
Univ., St Louis; Tel AVIV
A radrologrc scoring system indicated that female rats show thinner than normal femoral cortices 6 mos postovanectomy. We tested the hypothesis that this poor osteogenic record was due in-part to a deficit in the numbers and/or proliferative and osteogenic potential of marrow (osteoprogenitor) stromal cells. In vitro clonal growth (FCFUs) of stromal cells from ovariectomized (OVX) rats was significantly impaired. Yet, in vivo, cells from Sham-op and OVX’d rats proved to have equal osteogenic potential when implanted in millipore diffusion chambers, or implanted i.m in association with an osteogenic demineralized bone matrix ( = Composite Graft). The in vitro proliferative potential and clonal growth of marrow stromal cells from OVX’d rats was significantly enhanced by long-term Dihydrotachysterol (DHT)-treatment (6 mos), as was their osteogenic expression in millipore chambers and response to an osteoinductive DBM. The observation that the in vivo osteogenic performance of OVX’d marrow stromal cells was normal at sites away from bone suggests that stromal cell numbers are normal, but that the mechanisms leading to osteopenia may involve an abnormality in cell-matrix interactions.
IDIOPATHIC HYPERCALCIURIA (I.H.) AND HEREDITARY HYPOPHOSPHATEMIA RICKETS (H.H.R.H.)-TWO PHENOTYPICAL EXPRESSIONS A COMMON GENETIC DEFECT M. Treder, D. Modai, U. Shaked, R. Samuel, R. Arie, A. Halabe, Y. Maor, J. Weisgarten, Z. Averbukh, S Edelstein, U.A. Liberman
OF