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Histomorphometric Analysis of Bone Biopsies from the Iliac Crest of Adults with Cystic Fibrosis

Department of Cystic Fibrosis, Royal Brompton Hospital, Imperial College, London; Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge; and Department of Pathology, University of Wales College of Medicine, Cardiff, United Kingdom

Correspondence and requests for reprints should be addressed to Dr. Sarah L. Elkin, 45 Granville Road, Barnet, Hertfordshire, EN5 4DS, UK. E-mail: s.elkin{at}doctors.org.uk

	ABSTRACT

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This study reports the results of quantitative analysis of iliac bone histology in adults with cystic fibrosis (CF) and low bone mineral density (BMD). Twenty patients with CF had bone biopsies taken after double tetracycline labeling. Histomorphometric measurements were made by image analysis, and data were compared with those of healthy control subjects. Cancellous bone area was lower in the patients with CF (p = 0.003), and there was a trend towards a decrease in cancellous bone connectivity. Bone formation rate at tissue level was significantly lower in patients with CF (p = 0.0002). Wall width, representing the amount of bone formed within individual remodeling units, was decreased (p < 0.0001), as was mineralizing perimeter and mineral apposition rate. Analysis of resorption cavities revealed lower cavity area, reconstructed surface lengths, and cavity depths (p < 0.003) in patients with CF, whereas eroded surface area was higher (p = 0.0004). Our results demonstrate low cancellous bone volume in adult patients with CF with low BMD, the main cause of which appears to be low bone formation at tissue and cellular level. Osteomalacia was diagnosed in one patient. This condition should be excluded as a cause of low bone mineral density in patients with CF and vitamin D insufficiency corrected.

Key Words: bone mineral density • bone resorption • bone formation

	INTRODUCTION

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It is now widely recognized that low bone mineral density (BMD) occurs in both children and adults with cystic fibrosis (CF) (1, 2). Studies suggest that both decreased bone accretion in childhood and increased bone resorption in adults are responsible for the low BMD (3–5). However, the underlying pathophysiology of the bone loss is still unclear. Patients with CF have multiple risk factors for osteoporosis, including low body weight, decreased physical activity (6), steroid treatment, hypogonadism, chronic infection, delayed puberty, and malabsorption (7). In addition, low 25-hydroxyvitamin D levels, which may be associated with secondary hyperparathyroidism and increased bone loss (vitamin D insufficiency) or osteomalacia (vitamin D deficiency), have been reported in several studies of patients with CF (2, 8, 9).

The pathophysiology of bone loss in patients with CF has not been clearly defined, and histomorphometric data are sparse. Haworth and coworkers (4) in an analysis of autopsy bone samples from patients with CF, most of whom had undergone lung transplantation, reported that there was evidence of both increased bone resorption and decreased formation. However, in the absence of tetracycline labeling, dynamic indices of bone formation and resorption could not be assessed. Assessment of bone turnover using biochemical markers has shown marked heterogeneity with evidence of increased bone turnover in some patients (2, 5, 10). Finally, the prevalence of osteomalacia in this patient group has not been established.

In this study we have assessed bone turnover and remodeling balance in iliac crest cancellous bone in a group of adults with CF and low BMD.

	METHODS

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Study Population
Twenty adults with CF were recruited sequentially from the outpatient clinic at the Royal Brompton Hospital. A diagnosis of CF had been made previously by a positive sweat test, gene analysis, and the appropriate clinical manifestations. All patients were known to have bone mineral density Z scores of less than -1.5 at the femoral neck, lumbar spine, or both when measured by dual energy X-ray absorptiometry (DXA). Patients were excluded if they had a systemic disease other than CF, were pregnant, postmenopausal, were taking or had been previously prescribed a bisphosphonate, or were post-transplantation. Patient characteristics are displayed in Table 1. All subjects were white; 9 were female; 10 had previously taken oral steroids (longer than 3 months duration), with 8 receiving prednisolone therapy (5–10 mg) at the time of biopsy; 7 were prescribed inhaled glucocorticoids. All were prescribed 900 IU daily of vitamin D. Nineteen were prescribed regular pancreatic enzyme supplements. The local ethics committee approved the study, and informed written consent was obtained from all participants in accordance with the Helsinki Declaration. Trans-Iliac crest biopsies were obtained using an 8-mm internal diameter trephine under either local anesthetic and mild sedation (n = 18) or general anesthetic for a minor surgical procedure. Nineteen patients received double tetracycline labeling before the biopsy (300 mg of demeclocycline twice daily for 2 days, followed by a 10-day gap, followed by 300 mg twice daily for 2 days, followed by the biopsy 2–4 days after the last dose) (11). One patient took demeclocycline for the 2 days before the biopsy only. All biopsies were coded and the histomorphometric analysis was performed "blind" by the same observer except for the eroded perimeter lengths and strut analysis, for which measurements were performed by another observer in 15 biopsies.

Bone Histomorphometry
Biopsies were embedded in LR White medium resin (London Resin Co., Aldermaston, UK) 8 µm undecalcified sections were cut with a Jung K microtome and stained by the von Kossa technique or with 1% toluidine blue. Histomorphometric assessment was made using a "Digicad" digitizing tablet and cursor with an LED point light source (Kontron Ltd F.R.G.) and an Olympus BHS-BH2 binocular transmitted light microscope with a BH2-DA drawing attachment (Olympus Optical Co. UK. Ptd., London, UK). All histomorphometric data are described according to ASBMR nomenclature (15).

Primary Measurements
Bone area/tissue area (B.Ar./T.Ar.), osteoid perimeter/bone perimeter (O.Pm/B.Pm), and osteoid seam width (O.Wi.) were measured on von Kossa–stained sections. The mean width of completed bone remodeling units (W.Wi) was measured on toluidine blue–stained sections viewed under polarized light at x156 magnification. Fluorescence microscopy was used to view the tetracycline labeling on six 15-µm unstained sections at x156 magnification. Additional methodology and the calculations used to obtain values for the mineralizing perimeter (Md.Pm.), mineral apposition rate (MAR), adjusted apposition rate (Aj.AR), mineralization lag time (MLT) and osteoid maturation period (OMT), tissue based bone formation rate (BFR/B.Pm), activation frequency (Acf), formation period (FP), and active formation period (FP[A+]) is provided in the online data supplement.

Measurement of Resorption Cavity Characteristics
The method described by Garrahan and coworkers (16) was adapted for use with the digitizing tablet and light cursor for measurement. Cavities were identified on toluidine blue–stained sections viewed under polarized light at x156 magnification and measured at x375 or x750 magnification depending on the size of the cavity. Criteria for the identification of resorption cavities are provided in the online data supplement. A minimum of 20 cavities was assessed for each biopsy. The following indices were obtained: mean eroded depth (E.De., µm), maximum eroded depth (E.De.Max., µm), eroded cavity area (E.Ar., µm²), mean reconstructed cavity length (µm), and length of cement line (µm). The eroded surface/bone perimeter (%) was calculated for each biopsy and the number of osteoclasts present per biopsy was noted.

Structural Analysis
Structural analysis of cancellous bone was performed as previously described (17, 18). Additional detail on the method for making these measurements is provided in the online data supplement. Marrow space star volume was determined by a method adapted from the original description by Vesterby and coworkers (19–21). Trabecular bone pattern factor (Tb.Pf) was assessed automatically by measuring the trabecular area, and perimeter within the active region of the binary image using the method described previously by Hahn and colleagues (22).

Laboratory Assessment
Venepuncture was performed on patients on the same day as the biopsy. Samples were separated within 1 hour and frozen to -20°C. Biochemical analysis was performed on all blood samples. Measurements performed were serum parathyroid hormone (PTH) and serum bone-specific alkaline phosphatase (BAP). A second void morning urine sample was collected from each subject for measurement of crosslinked N telopeptides (NTx) of type 1 collagen and creatinine. Additional detail on the method for making these measurements is provided in the online data supplement.

Statistical Analysis
Analyses were performed with SAS software (Crowthorne, UK) or Statistica for the MAC by StatSoft (Cambridge, UK).

Analysis of histomorphometric data was performed using an unpaired Student's t test after log transformation of the data. Results are expressed as the mean ± SEM. Relationships between markers of bone turnover and histomorphometric indices were examined using Spearman's correlation.

	RESULTS

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Details of the patients are shown in Table 1. One patient had osteomalacia as defined by strict histomorphometric criteria, with an increased osteoid seam width of 15.8 µm and a prolonged mineralization lag time of 107 days. The data from this biopsy were excluded from further analysis. Histomorphometric variables from patients and control subjects are shown in Tables 2– 4. Cancellous bone area was significantly lower in the CF group (p = 0.003). There was a decrease in bone formation rate at tissue level (p = 0.0002) and wall width (p < 0.0001). Osteoid width was not increased in the CF group; however, the mineralization lag time was significantly increased (p = 0.006; mean 52 days versus 20 days in control subjects). There was a significant decrease in both the mineral apposition rate (p = 0.03) and the mineralizing perimeter (p = 0.0002) in comparison with control subjects. Values for directly measured and calculated resorption cavity characteristics are shown in Table 3. Resorption cavity indices were all significantly reduced when compared with control subjects (p < 0.003). Osteoclast numbers were not increased. The results of structural analysis are shown in Table 4. There were no significant differences between the two groups. However, there was a trend towards decreased connectivity in the patients with CF with higher terminus to terminus strut length and marrow star volume. In addition, the node to loop and node to node strut lengths were lower in the subjects with CF than in control subjects. Figure 1 shows a representative CF bone biopsy in contrast to a control bone biopsy.

View larger version (147K): [in this window] [in a new window]   Figure 1. A representative CF bone biopsy in contrast to a control bone biopsy. (A) Toluidine Blue–stained section of iliac crest bone biopsy in a patient with CF showing decrease in cancellous bone connectivity and decreased cancellous bone area. Magnification: x40. (B) CF: Higher power magnification of boxed area (magnification: x100). White arrows = thin wall width of bone packets. Black arrows = crenated surface of a shallow resorption cavity. (C) Normal: Toluidine Blue–stained section of iliac crest bone biopsy from a normal patient demonstrating good connectivity of cancellous bone. Magnification: x40. (D) Normal: higher power magnification of boxed area showing normal wall width of two complete packets. White arrows = normal wall width of bone packets. Magnification: x100.

Laboratory Measurements
Serum samples were available in 19 patients and urine samples in 17. Results are shown in Table 5. Sixty-three percent (12 patients) had raised urine NTx, and two patients had raised serum bone specific alkaline phosphatase. No correlation was found between the markers of bone turnover (bone specific alkaline phosphatase, NTx) and any histomorphometric indices (eroded perimeter, osteoid perimeter, bone formation rate, mineral apposition rate, and indices of bone resorption). Bone specific alkaline phosphatase was positively correlated with urinary NTx (r = 0.66, p = 0.003).

	DISCUSSION

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Our results differ in some respects to those reported by Haworth and coworkers (4). Thus, although reduced cancellous bone area and a reduction in osteoblast number was found in their study, the authors also reported evidence of increased osteoclast number and activity and concluded that bone loss in their patients was due to the combination of reduced formation and increased resorption. However, because the bone samples were obtained at autopsy, no tetracycline labeling was performed and thus dynamic indices of formation and resorption could not be assessed. Furthermore, the majority of the patient population in their study had undergone lung transplantation and had consequently received high doses of glucocorticoids; thus the evidence of increased resorption may have been related to transplantation rather than to CF per se (21). Finally, the fact that autopsy samples were studied implies that the patients had recently been severely ill, with chronic infection and immobility. All of these factors would predispose to increased resorption and may explain the different findings in our study, in which patients were in relatively good health at the time of investigation.

The present study reports a significant reduction in mineralizing perimeter in the CF group indicating reduced bone formation at tissue level. In addition, four of the biopsies showed "fuzzy," poorly defined labels which, together with the increase in MLT and decrease in MAR in the group as a whole, indicates a mineralization defect. Twenty-five percent of subjects had an MLT of greater than 100 days and an MAR of less than 0.55 µm/day. However, osteoid seam width was normal in 18 of the 20 patients with CF, indicating that the mineralization defect was generally mild. Similar changes have been described in patients with inflammatory bowel disease (14).

The reduction in mean wall width and MAR in patients with CF indicates reduced osteoblastic activity. This could be due to a depression of mature osteoblast function or a shortening of the osteoblast life span resulting from increased apoptosis. This reduction in bone formation is similar to that seen in patients taking glucocorticoids; furthermore, a subgroup analysis of the glucocorticoid-prescribed patients with CF revealed a greater reduction in bone formation at tissue level when compared with non–glucocorticoidoid users. Osteoblastic activity was not affected. Thus, although glucocorticoids contribute to reduced bone formation in some patients, other factors must also operate.

Patients with CF are at risk of developing deficiencies of fat-soluble vitamins. Vitamin K deficiency is reported to occur in patients with CF (23, 24). Consequently, a recent CF Foundation consensus document on pediatric nutrition recommends that vitamin K supplements should be provided to all patients (25). Vitamin K is a cofactor in the carboxylation of glutamic acid residues, such as osteocalcin. Several studies have demonstrated that a poor vitamin K status is associated with an increased risk of osteoporotic fractures (26). Whether vitamin K deficiency contributes to the osteopenia found in patients with CF is unknown and further studies are required. Many studies in patients with CF have documented low serum 25OHD (3, 8, 27). We have previously reported serum 25OHD levels of below 25 nmol/L in 36% of adult patients despite daily supplementation with 800–900 IU of vitamin D (2). Vitamin D insufficiency can lead to decreased intestinal calcium absorption and thus a decrease in available calcium. This results in stimulation of parathyroid hormone secretion and an increase in bone turnover. Severe vitamin D deficiency can lead to osteomalacia and indeed in the present study one biopsy revealed this disease. The patient had a high serum PTH (199 pg/ml), a low serum 25OHD (20 nmol/L), and increased indices of resorption. It therefore appears that insufficient intake of vitamin D may sometimes contribute to CF bone disease. In our unit we recommend that patients should have serum 25OHD levels measured at least once yearly and if insufficient (< 50 nmol/L), despite supplementation, additional vitamin D is given, either as extra daily tablets or larger weekly doses. This is especially important if serum levels are low in the autumn months.

The increase in markers of bone resorption found in this and other studies in adults with CF (2, 5, 28) suggests that bone resorption is increased in some patients. Histomorphometric data from the present study do not show increased resorption in the group as a whole. However, there was considerable heterogeneity in resorption measurements in the patients studied, at least two of the subjects having larger resorption cavities than the control mean value. In addition, the patient with the greatest mean cavity depth also had the highest resorption biomarker values. Although biochemical markers of bone turnover show marked variability, with a large diurnal (50%), seasonal (12%) (29), and within-subject variation (27%), (30) it is likely that increased resorption does contribute to bone disease in some patients with CF.

Recently there have been several reports of the use of oral or intravenous bisphosphonates in patients with bone disease associated with CF (31). Although the main mechanism of action of these agents is to inhibit the recruitment and function of osteoclasts, there is increasing evidence that they also enhance the bone-forming activities of osteoblasts (32, 33) and prevent osteoblast apoptosis (34). Therefore, the finding of decreased bone formation does not preclude a therapeutic effect of bisphosphonates in CF bone disease. Indeed, two studies (both using intravenous pamidronate) in adults with CF have shown significant increases in the bone mineral density of the lumbar spine in the treatment group compared with control subjects, both in nontransplant (35) and post–lung transplant patients (36). The finding in the present study that oral glucocorticoids may compound the effects of CF on bone further supports the use of bisphosphonates. Serum 25OHD and PTH levels should be checked before commencing bisphosphonate therapy to exclude osteomalacia, because some bisphosphonates have inhibitory effects on mineralization.

In conclusion, the results of our study support the contention that bone disease in patients with CF is characterized predominantly by low bone turnover and reduced bone formation at the cellular level. In our study, evidence of increased bone resorption was not demonstrated in the majority of patients but it is likely that factors such as infection, vitamin D deficiency, glucocorticoids, and immobility may sometimes result in such changes. This would be supported by the finding, in several studies, of increased levels of biochemical markers of bone turnover in a proportion of patients with CF. Finally, the finding of osteomalacia in one patient emphasizes the need to exclude this condition as a cause of low bone mineral density in patients with CF and to correct vitamin D deficiency, which is known to be prevalent in the CF population.

	Acknowledgments

 
The authors are grateful to Professor Duncan Geddes for allowing us to recruit patients under his care, Jackie Turner for her help with the statistical analysis, and Dr. David Adeboyeku and Sandra Scott for help in recruitment and all the patients who gave up their valuable time.

	FOOTNOTES

 
Supported by the Cystic Fibrosis Trust and the Wellcome Trust.

This article has an online data supplement, which is accessible from this issue's table of contents online at www.atsjournals.org

Received in original form June 20, 2002; accepted in final form September 9, 2002

	REFERENCES

TOP ABSTRACT INTRODUCTION METHODS RESULTS DISCUSSION REFERENCES

 

1. Gibbens DT, Gilsanz V, Boechat MI, Dufer D, Carlson ME, Wang CI. Osteoporosis in cystic fibrosis. J Pediatr 1988;113:295–300.[CrossRef][Medline]
2. Elkin SL, Fairney A, Burnett S, Kemp M, Kyd P, Burgess J, Compston JE, Hodson ME. Vertebral deformities and low bone mineral density in adults with cystic fibrosis: a cross-sectional study. Osteoporos Int 2001;12:366–372.[CrossRef][Medline]
3. Bhudhikanok GS, Wang MC, Marcus R, Harkins A, Moss RB, Bachrach LK. Bone acquisition and loss in children and adults with cystic fibrosis: a longitudinal study. J Pediatr 1998;133:18–27.[CrossRef][Medline]
4. Haworth CS, Webb AK, Egan JJ, Selby PL, Hasleton PS, Bishop PW, Freemont TJ. Bone histomorphometry in adult patients with cystic fibrosis. Chest 2000;118:434–439.[Abstract/Free Full Text]
5. Aris RM, Ontjes DA, Buell HE, Blackwood AD, Lark RK, Caminiti M, Brown SA, Renner JB, Chalermskulrat W, Lester GE. Abnormal bone turnover in cystic fibrosis adults. Osteoporos Int 2002;13:151–157.[CrossRef][Medline]
6. Elkin SL, Williams L, Moore M, Hodson ME, Rutherford OM. Relationship of skeletal muscle mass, muscle strength and bone mineral density in adults with cystic fibrosis. Clin Sci (Lond) 2000;99:309–314.[Medline]
7. Ott SM, Aitken ML. Osteoporosis in patients with cystic fibrosis. Clin Chest Med 1998;19:555–567.[CrossRef][Medline]
8. Donovan DSJ, Papadopoulos A, Staron RB, Addesso V, Schulman L, McGregor C, Cosman F, Lindsay RL, Shane E. Bone mass and vitamin D deficiency in adults with advanced cystic fibrosis lung disease. Am J Respir Crit Care Med 1998;157:1892–1899.[Abstract/Free Full Text]
9. Hanly JG, McKenna MJ, Quigley C, Freaney R, Muldowney FP, FitzGerald MX. Hypovitaminosis D and response to supplementation in older patients with cystic fibrosis. Q J Med 1985;56:377–385.
10. Baroncelli GI, De Luca F, Magazzu G, Arrigo T, Sferlazzas C, Catena C, Bertelloni S, Saggese G. Bone demineralization in cystic fibrosis: evidence of imbalance between bone formation and degradation. Pediatr Res 1997;41:397–403.[Medline]
11. Frost HM. Tetracycline based histological analysis of bone remodelling. Calcif Tiss Int 1969;3:211–237.
12. Vedi S, Compston JE, Webb A, Tighe JR. Histomorphometric analysis of bone biopsies from the iliac crest of normal British subjects. Metab Bone Dis Relat Res 1982;4:231–236.[CrossRef][Medline]
13. Vedi S, Compston JE, Webb A, Tighe JR. Histomorphometric analysis of dynamic parameters of trabecular bone formation in the iliac crest of normal British subjects. Metab Bone Dis Relat Res 1983;5:69–74.[Medline]
14. Croucher PI, Vedi S, Motley RJ, Garrahan NJ, Stanton MR, Compston JE. Reduced bone formation in patients with osteoporosis associated with inflammatory bowel disease. Osteoporos Int 1993;3:236–241.[CrossRef][Medline]
15. Parfitt AM, Drezner MK, Glorieux FH, Kanis JA, Malluche H, Meunier PJ, Ott SM, Recker RR. Bone histomorphometry: standardization of nomenclature, symbols, and units. Report of the ASBMR Histomorphometry Nomenclature Committee. J Bone Miner Res 1987;2:595–610.[Medline]
16. Garrahan NJ, Croucher PI, Compston JE. A computerised technique for the quantitative assessment of resorption cavities in trabecular bone. Bone 1990;11:241–245.[Medline]
17. Croucher PI, Garrahan NJ, Compston JE. Assessment of cancellous bone structure: comparison of strut analysis, trabecular bone pattern factor, and marrow space star volume. J Bone Miner Res 1996;11:955–961.[Medline]
18. Garrahan NJ, Mellish RW, Compston JE. A new method for the two-dimensional analysis of bone structure in human iliac crest biopsies. J Microsc 1986;142:341–349.[Medline]
19. Vesterby A. Star volume of marrow space and trabeculae in iliac crest: sampling procedure and correlation to star volume of first lumbar vertebra. Bone 1990;11:149–155.[Medline]
20. Vesterby A, Gundersen HJ, Melsen F. Star volume of marrow space and trabeculae of the first lumbar vertebra: sampling efficiency and biological variation. Bone 1989;10:7–13.[Medline]
21. Vedi S, Greer S, Skingle SJ, Garrahan NJ, Ninkovic M, Alexander GA, Compston JE. Mechanism of bone loss after liver transplantation: a histomorphometric analysis. J Bone Miner Res 1999;14:281–287.[CrossRef][Medline]
22. Hahn M, Vogel M, Pompesius-Kempa M, Delling G. Trabecular bone pattern factor: a new parameter for simple quantification of bone microarchitecture. Bone 1992;13:327–330.[Medline]
23. Rashid M, Durie P, Andrew M, Kalnins D, Shin J, Corey M, Tullis E, Pencharz PB. Prevalence of vitamin K deficiency in cystic fibrosis. Am J Clin Nutr 1999;70:378–382.[Abstract/Free Full Text]
24. Becker LT, Ahrens RA, Fink RJ, O'Brien ME, Davidson KW, Sokoll LJ, Sadowski JA. Effect of vitamin K supplementation on vitamin K status in cystic fibrosis patients. J Pediatr Gastroenterol Nutr 1997;24:512–517.[CrossRef][Medline]
25. Cystic Fibrosis Foundation Consensus Conference; Pediatric Nutrition for Patients with Cystic Fibrosis. March 28–29, 2001;vol X: sec 1.
26. Vermeer C, Jie KS, Knapen MH. Role of vitamin K in bone metabolism. Annu Rev Nutr 1995;15:1–22.[CrossRef][Medline]
27. Stead RJ, Houlder S, Agnew J, Thomas M, Hodson ME, Batten JC, Dandona P. Vitamin D and parathyroid hormone and bone mineralization in adults with cystic fibrosis. Thorax 1988;43:190–194.[Abstract]
28. Haworth CS, Selby PL, Webb AK, Dodd ME, Musson H, McL Niven R, Economou G, Horrocks AW, Freemont AJ, Mawer EB, et al. Low bone mineral density in adults with cystic fibrosis. Thorax 1999;54:961–967.[Abstract/Free Full Text]
29. Woitge HW, Scheidt-Nave C, Kissling C, Leidig-Bruckner G, Meyer K, Grauer A, Scharla SH, Ziegler R, Seibel MJ. Seasonal variation of biochemical indexes of bone turnover: results of a population-based study. J Clin Endocrinol Metab 1998;83:68–75.[Abstract/Free Full Text]
30. Hannon R, Eastell R. Preanalytical variability of biochemical markers of bone turnover. Osteoporos Int 2000;11(Suppl 6):S30–S44.
31. Brenckmann C, Papaioannou A. Bisphosphonates for osteoporosis in people with cystic fibrosis. Cochrane Database Syst Rev 2001;4:CD002010.
32. Reinholz GG, Getz B, Pederson L, Sanders ES, Subramaniam M, Ingle JN, Spelsberg TC. Bisphosphonates directly regulate cell proliferation, differentiation, and gene expression in human osteoblasts. Cancer Res 2000;60:6001–6007.[Abstract/Free Full Text]
33. Fromigue O, Body JJ. Bisphosphonates influence the proliferation and the maturation of normal human osteoblasts. J Endocrinol Invest 2002;25:539–546.[Medline]
34. Plotkin LI, Weinstein RS, Parfitt AM, Roberson PK, Manolagas SC, Bellido T. Prevention of osteocyte and osteoblast apoptosis by bisphosphonates and calcitonin. J Clin Invest 1999;104:1363–1374.[Medline]
35. Haworth CS, Selby PL, Adams JE, Mawer EB, Horrocks AW, Webb AK. Effect of intravenous pamidronate on bone mineral density in adults with cystic fibrosis. Thorax 2001;56:314–316.[Abstract/Free Full Text]
36. Aris RM, Lester GE, Renner JB, Winders A, Denene BA, Lark RK, Ontjes DA. Efficacy of pamidronate for osteoporosis in patients with cystic fibrosis following lung transplantation. Am J Respir Crit Care Med 2000;162(3 Pt 1):941–946.[Abstract/Free Full Text]

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