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The development of new and better implant materials adapted to osteoporotic bone is still urgently required. Therefore, osteoporotic muscarinic acetylcholine receptor M3 (M3 mAChR) knockout (KO) and corresponding wild type (WT) mice underwent osteotomy in the distal femoral metaphysis. Fracture gaps were filled with a pasty &alpha, tricalcium phosphate (&alpha, TCP)-based hydroxyapatite (HA)-forming bone cement containing mesoporous bioactive CaP-SiO2 glass particles (cement/MBG composite) with or without Brain-Derived Neurotrophic Factor (BDNF) and healing analyzed after 35 days. Histologically, bone formation was significantly increased in WT mice that received the BDNF-functionalized cement/MBG composite compared to control WT mice without BDNF. Cement/MBG composite without BDNF increased bone formation in M3 mAChR KO mice compared to equally treated WT mice. Mass spectrometric imaging showed that the BDNF-functionalized cement/MBG composite implanted in M3 mAChR KO mice was infiltrated by newly formed tissue. Leukocyte numbers were significantly lower in M3 mAChR KO mice treated with BDNF-functionalized cement/MBG composite compared to controls without BDNF. C-reactive protein (CRP) concentrations were significantly lower in M3 mAChR KO mice that received the cement/MBG composite without BDNF when compared to WT mice treated the same. Whereas alkaline phosphatase (ALP) concentrations in callus were significantly increased in M3 mAChR KO mice, ALP activity was significantly higher in WT mice. Due to a stronger effect of BDNF in non osteoporotic mice, higher BDNF concentrations might be needed for osteoporotic fracture healing. Nevertheless, the BDNF-functionalized cement/MBG composite promoted fracture healing in non osteoporotic bone.

High frequency of osteoporosis is found in postmenopausal women where several molecular components were identified to be involved in bone loss that subsequently leads to an increased fracture risk. Bone loss has already been determined in male mice with gene deficiency of muscarinic acetylcholine receptor M3 (M3R-KO). Here we asked whether bone properties of female 16-week old M3R-KO present similarities to osteoporotic bone loss by means of biomechanical, radiological, electron microscopic, cell- and molecular biological methods. Reduced biomechanical strength of M3R-KO correlated with cortical thickness and decreased bone mineral density (BMD). Femur and vertebrae of M3R-KO demonstrated a declined trabecular bone volume, surface, and a higher trabecular pattern factor and structure model index (SMI) compared to wild type (WT) mice. In M3R-KO, the number of osteoclasts as well as the cathepsin K mRNA expression was increased. Osteoclasts of M3R-KO showed an estimated increase in cytoplasmic vesicles. Further, histomorphometrical analysis revealed up-regulation of alkaline phosphatase. Osteoblasts and osteocytes showed a swollen cytoplasm with an estimated increase in the amount of rough endoplasmatic reticulum and in case of osteocytes a reduced pericellular space. Thus, current results on bone properties of 16-week old female M3R-KO are related to postmenopausal osteoporotic phenotype. Stimulation and up-regulation of muscarinic acetylcholine receptor subtype M3 expression in osteoblasts might be a possible new option for prevention and therapy of osteoporotic fractures. Pharmacological interventions and the risk of side effects have to be determined in upcoming studies.

Butyrylcholinesterase (BChE) degrades acetylcholine in addition to acetylcholinesterase (AChE) which is involved in embryonic development of limbs. Since BChE is expressed by osteoblast-like cells we asked whether it is functional in adult bone remodeling. We addressed this issue by analyzing BChE gene-deficient mice (BChE-KO). Bones were extracted from 16-week old female BChE-KO and corresponding wild type mice (WT). Femoral bones were used for biomechanical testing and μCT evaluation of cancellous and cortical bone. Also vertebrae Th12 and L1 were investigated with μCT while L3 was used for tartrate-resistant acidic phosphatase (TRAP) histomorphometry and Th10 for gene expression analysis by means of real-time RT-PCR. BChE-KO did not reveal significant differences in biomechanical bone strength and bone mineral density determined by μCT. Microarchitecture of cancellous and cortical bone showed an increase in μCT parameters like trabecular thickness, trabecular separation, and relative cortical bone area of femoral BChE-KO bone compared to WT. In vertebrae no changes of microstructure and mRNA expression were detected. However, osteoclast histomorphometry with TRAP stained sections demonstrated a significant increase in relative osteoclast number. In conclusion, in adult murine bone the role of BChE is limited to bone specific changes in microarchitecture and to an increase in relative number of bone resorbing osteoclasts whereas the main collagen resorbing enzyme Cathepsin-K (CtsK) was stably expressed. Besides, AChE might be able to compensate the lack of BChE. Thus, further analyses using bone tissue specific AChE BChE cre–lox double knockout mice would be helpful.

Bone substitute materials loaded with mediators that stimulate fracture healing are demanded in the clinical treatment in trauma surgery and orthopedics. Brain-derived neurotrophic factor (BDNF) enhances the proliferation and differentiation of mesenchymal stem cells into osteoblast. To load the implants with BDNF, a drug delivery system that allows the release of BDNF under spatiotemporal control would improve functionality. Polyelectrolyte complex nanoparticles (PECNP) have been reported as a suitable drug delivery system. The suitability of PECNP in contact with osteocytes as the main cell type of bone is not known so far. Thus, we aimed to verify that BDNF and PECNP loaded with BDNF (PECNP+BDNF) as well as pure PECNP have no negative effects on osteocytes in vitro. Therefore, the murine osteocyte cell line MLO-Y4 was treated with BDNF and PECNP+BDNF. The effects on proliferation were analyzed by the BrdU test (n = 5). The results demonstrated a significant increase in proliferation 24 h after BDNF application, whereas PECNP+BDNF did not lead to significant changes. Thus, we conclude that BDNF is an appropriate mediator to stimulate osteocytes. Since the addition of PECNP did not affect the viability of osteocytes, we conclude that PECNP are a suitable drug delivery system for bone implants.

Donepezil inhibits the acetylcholine degradation molecule acetylcholinesterase (AChE). Clinical studies reported that Alzheimer's disease (AD) patients with hip fractures had improved bone quality and better fracture healing if they were treated with AD medication donepezil. We asked whether mesenchymal stroma cells (MSC) from an osteoporosis sheep model treated with donepezil increased their proliferation rate and mRNA expression.Sheep were divided into 4 groups: a) untreated control group, b) sheep with bilateral ovariectomy (OVX), c) sheep with OVX and malnutrition, and d) sheep with OVX, malnutrition, and application of corticosteroid. After 8 months MSC were isolated of iliac crest biopsy, treated with donepezil, and AChE activity, proliferation rate, and mRNA expression were analyzed.Application of donepezil resulted in a significant decrease of AChE activity. Inhibition of AChE did not lead to a significant increase in proliferation. Expression of the osteogenic marker osteocalcin was not regulated by donepezil while the mRNA concentration of collagen was increased.AChE inhibition via donepezil resulted in an increased synthesis of osteoid which consists mainly of collagen. Thus, we suppose that increased acetylcholine levels through AChE inhibition do not support MSC proliferation but osteogenic activity probably combined with osteogenic differentiation.

Alterations in bone strength and structure were found in knockout (KO) mouse strains with deletion of several acetylcholine receptors. Interestingly, the expression of the nicotinic acetylcholine receptors (nAChR) subunit α10 was down-regulated in osteogenic differentiated mesenchymal stem cells of patients with osteoporosis whereas the expression of subunit α9 was not altered. Since nAChR subunits α9 and α10 are often combined in a functional receptor, we analyzed here the bone of adult female KO mice with single deletion of either nAChR alpha9 (α9KO) or alpha10 (α10KO). Biomechanical testing showed a significant decrease of bending stiffness and maximal breaking force in α9KO compared to their corresponding wild type mice. Furthermore, an increase in trabecular pattern factor (Tb.Pf) and structure model index (SMI) was detected by μCT in α9KO indicating reduced bone mass. On the mRNA level a decrease of Collagen 1α1 and Connexin-43 was measured by real-time RT-PCR in α9KO while no alteration of osteoclast markers was detected in either mouse strain. Using electron microcopy we observed an increase in the number of osteocytes that showed signs of degeneration and cell death in the α9KO compared to their wild type mice, while α10KO showed no differences. In conclusion, we demonstrate alterations in bone strength, structure and bio-marker expression in α9KO mice which imply the induction of osteocyte degeneration. Thus, our data suggest that nAChR containing the α9 subunit might be involved in the homeostasis of osteocytes and therefore in bone mass regulation.

Fracture treatment in osteoporotic patients is still challenging. Osteoporosis emerges when there is an imbalance between bone formation and resorption in favor of resorption by osteoclasts. Thus, new implant materials for osteoporotic fracture treatment should promote bone formation and reduce bone resorption. Nanoparticles can serve as drug delivery systems for growth factors like Brain-Derived Neurotrophic Factor (BDNF), which stimulated osteoblast differentiation. Therefore, polyelectrolyte complex nanoparticles (PEC-NPs) consisting of poly(l-lysine) (PLL) and cellulose sulfate (CS), with or without addition of BDNF, were used to analyze their effect on osteoclasts in vitro. Live cell images showed that osteoclast numbers decreased after application of high PLL/CS PEC-NPs concentrations independent of whether BDNF was added or not. Real-time RT-PCR revealed that relative mRNA expression of cathepsin K and calcitonin receptor significantly declined after incubation of osteoclasts with high concentrations of PLL/CS PEC-NPs. Furthermore, Enzyme-Linked Immunosorbent Assay indicated that tartrate-resistant acidic phosphatase 5b activity was significantly reduced in the presence of high PLL/CS PEC-NPs concentrations. Consistent with these results, the pit formation analysis showed that less hydroxyapatite was resorbed by osteoclasts after incubation with high concentrations of PLL/CS PEC-NPs. BDNF had no influence on osteoclasts. We conclude that highly concentrated PLL/CS PEC-NPs dosages decreased osteoclastogenesis and osteoclasts activity. Moreover, BDNF might be a promising growth factor for osteoporotic fracture treatment since it did not increase osteoclast activity.

Acetylcholinesterase (AChE) hydrolyzes acetylcholine (ACh) to acetate and choline and thereby terminates nerve impulse transmission. ACh is also expressed in bone tissue and enhances here proliferation and differentiation of osteoblasts, which makes it interesting to investigate effects of AChE deficiency on bone. To our knowledge, this is the first study that analyzed bone of heterozygous acetylcholinesterase-knockout (AChE-KO) mice. Tibia, femur, thoracic and lumbar vertebrae of 16-week-old female heterozygous AChE-KO mice and their corresponding wildtypes (WT) were analyzed using real-time RT-PCR, dual-energy X-ray absorptiometry, biomechanics, micro-computed tomography, histology and histomorphometry. Our data revealed that heterozygous AChE-KO did not cause negative effects upon bone parameters analyzed. In contrast, the number of osteoclasts per perimeter was significantly reduced in lumbar vertebrae. In addition, we found a significant decrease in trabecular perimeter of lumbar vertebrae and cortical area fraction (Ct.Ar/Tt.Ar) in the mid-diaphysis of femurs of AChE-KO mice compared to their WT. Therefore, presumably a local homozygous knockout of AChE or AChE-inhibitor administration might be beneficial for bone formation due to ACh accumulation. However, many other bone parameters analyzed did not differ statistically significantly between AChE-KO and WT mice. That might be reasoned by the compensating effect of butyrylcholinesterase (BChE).

Background Recently, analysis of bone from knockout mice identified muscarinic acetylcholine receptor subtype M3 (mAChR M3) and nicotinic acetylcholine receptor (nAChR) subunit α2 as positive regulator of bone mass accrual whereas of male mice deficient for α7-nAChR (α7KO) did not reveal impact in regulation of bone remodeling. Since female sex hormones are involved in fair coordination of osteoblast bone formation and osteoclast bone degradation we assigned the current study to analyze bone strength, composition and microarchitecture of female α7KO compared to their corresponding wild-type mice (α7WT). Methods Vertebrae and long bones of female 16-week-old α7KO (n = 10) and α7WT (n = 8) were extracted and analyzed by means of histological, radiological, biomechanical, cell- and molecular methods as well as time of flight secondary ion mass spectrometry (ToF-SIMS) and transmission electron microscopy (TEM). Results Bone of female α7KO revealed a significant increase in bending stiffness (p

Background Cholinergic signaling via muscarinic acetylcholine receptors (mAChR) is known to influence various physiological functions. In bone, M3 mAChR and M5 mAChR were identified on the membrane of osteoblast-like cells. M3 mAChR seems to be particularly relevant for bone physiology, as signaling via this receptor was reported to increase bone formation and decrease bone resorption. Thus, in the present study we investigated the relative mRNA expression of M3 and M5 mAChR in bones of a rat osteoporosis model. Material and methods Osteoporosis was induced in Sprague-Dawley rats by bilateral ovariectomy and additional feeding of a diet deficient in calcium, vitamins C, D2, D3, and phosphorus, and free of soy and phytoestrogen. After a period of 3, 12, and 14 months, relative mRNA expression of M3 mAChR and M5 mAChR was analyzed in the 11th thoracic vertebra by real-time RT-PCR. Results Relative mRNA expression of M3 mAChR was significantly reduced in bones of osteoporotic rats compared to sham operated animals that served as controls. Further, M3 mAChR mRNA expression was significantly down-regulated when comparing 14-month osteoporotic rats to 3-month osteoporotic rats. Relative M5 mAChR mRNA was expressed to a lesser extent than M3 mAChR and did not show significant differences in mRNA expression level between the experimental groups. Conclusions M3 mAChR mRNA expression was reduced upon induction of osteoporosis and progression of disease was associated with further decrease of this receptor, indicating that M3 mAChR is involved in the development and regulation of osteoporosis.

Insertion of bone substitution materials accelerates healing of osteoporotic fractures. Biodegradable materials are preferred for application in osteoporotic patients to avoid a second surgery for implant replacement. Degraded implant fragments are often absorbed by macrophages that are removed from the fracture side via passage through veins or lymphatic vessels. We investigated if lymphatic vessels occur in osteoporotic bone defects and whether they are regulated by the use of different materials. To address this issue osteoporosis was induced in rats using the classical method of bilateral ovariectomy and additional calcium and vitamin deficient diet. In addition, wedge-shaped defects of 3, 4, or 5 mm were generated in the distal metaphyseal area of femur via osteotomy. The 4 mm defects were subsequently used for implantation studies where bone substitution materials of calcium phosphate cement, composites of collagen and silica, and iron foams with interconnecting pores were inserted. Different materials were partly additionally functionalized by strontium or bisphosphonate whose positive effects in osteoporosis treatment are well known. The lymphatic vessels were identified by immunohistochemistry using an antibody against podoplanin. Podoplanin immunopositive lymphatic vessels were detected in the granulation tissue filling the fracture gap, surrounding the implant and growing into the iron foam through its interconnected pores. Significant more lymphatic capillaries were counted at the implant interface of composite, strontium and bisphosphonate functionalized iron foam. A significant increase was also observed in the number of lymphatics situated in the pores of strontium coated iron foam. In conclusion, our results indicate the occurrence of lymphatic vessels in osteoporotic bone. Our results show that lymphatic vessels are localized at the implant interface and in the fracture gap where they might be involved in the removal of lymphocytes, macrophages, debris and the implants degradation products. Therefore the lymphatic vessels are involved in implant integration and fracture healing.

Background & Aims Little is known about the pathogenic mechanisms of chronic pancreatitis. We investigated the roles of complement component 5 (C5) in pancreatic fibrogenesis in mice and patients. Methods Chronic pancreatitis was induced by ligation of the midpancreatic duct, followed by a single supramaximal intraperitoneal injection of cerulein, in C57Bl6 (control) and C5-deficient mice. Some mice were given injections of 2 different antagonists of the receptor for C5a over 21 days. In a separate model, mice were given injections of cerulein for 10 weeks to induce chronic pancreatitis. Direct effects of C5 were studied in cultured primary cells. We performed genotype analysis for the single-nucleotide polymorphisms rs 17611 and rs 2300929 in C5 in patients with pancreatitis and healthy individuals (controls). Blood cells from 976 subjects were analyzed by transcriptional profiling. Results During the initial phase of pancreatitis, levels of pancreatic damage were similar between C5-deficient and control mice. During later stages of pancreatitis, C5-deficient mice and mice given injections of C5a-receptor antagonists developed significantly less pancreatic fibrosis than control mice. Primary pancreatic stellate cells were activated in vitro by C5a. There were no differences in the rs 2300929 SNP between subjects with or without pancreatitis, but the minor allele rs17611 was associated with a significant increase in levels of C5 in whole blood. Conclusions In mice, loss of C5 or injection of a C5a-receptor antagonist significantly reduced the level of fibrosis of chronic pancreatitis, but this was not a consequence of milder disease in early stages of pancreatitis. C5 might be a therapeutic target for chronic pancreatitis.

s / Pancreatology 299 pylorus-preserving PD (PPPD). Thirty-seven cases were combined with resection of additional organs or major vessels. Data were reviewed and analyzed in retrospective way. Results: There were 612 male and 398 female patients in this group, with mean age of 57.3 11.8 year-old. The most common pathological diagnosis were pancreatic adenocarcinomas (392/1010, 38.8%), ampullary adenocarcinomas (262/1010, 25.9%) and duodenal adenocarcinomas (144/1010, 14.3%). Intraoperative data showed a mean operation time of 312 73min and a mean estimated blood loss of 575 307mL. The most frequent postoperative complications were grade BþC delayed gastric emptying (226/1010, 22.4%), hemorrhage (102/1010, 10.1%), pancreatic fistula (101/1010, 10%), chyle fistula (71/ 1010, 7.0%), and intraabdominal infection (49/1010, 4.9%). Reoperation occurred in 38 patients (38/1010, 3.8%). Thirty-days mortality rate was 0.6% (6/1010). Length of postoperative hospital stay was 19.7 10.5 days. Conclusion: Though its mortality rate dropped to less than 1%, PD or PPPD remains a challenging procedure for surgeons, for its substantial postoperative complication rates. Technique proficiency may improve the outcomes. O-32 Abstract id: 218. Pancreatic Exocrine Insufficiency (PEI) in chronic pancreatitis (CP) and cystic fibrosis (CF) patients: Combining clinician insights and existing literature to develop a conceptual model to aid in the identification and management of PEI Markus Lerch , Philippe Levy , David Sanders , Linda AbetzWebb , Mathias Schifflers , Jean-Marc Haeusler . University Medicine Greifswald, Ernst-Moritz-Arndt University, Germany University Denis Diderot-Paris VII, Beaujon Hospital, Paris, France 3 Royal Hallamshire Hospital & the University of Sheffield, Sheffield, United Kingdom Adelphi Values, Cheshire, United Kingdom Abbott Products Operations AG, Allschwil, Switzerland Introduction: PEI occurs when pancreatic exocrine secretions are inadequate to maintain normal digestive function, resulting in nutrient malabsorption. PEI is most commonly recognized in adults with CP and children with CF. Aims: To develop a conceptual model capturing the burden of PEI and explore clinicians’ experience of treating PEI. Materials & methods: A PEI conceptual model was developed through a literature search and review of patient-reported outcomes. 10 specialists in France, Germany and England were interviewed with open-ended questions exploring symptoms, diagnosis, treatment and consequences of PEI. Interviews were qualitatively analyzed and concepts were mapped against the conceptual model. Results: The most common diagnostic method used was the faecal elastase test. However, two clinicians stated that diagnostic tests were not always conducted due to costs or patients’ preference. CF patients were often diagnosed and treated immediately upon presenting with PEI symptoms. PEI was thought to be underdiagnosed in CP patients. Clinician reported symptoms and impacts mapped closely with the conceptual model. Six clinicians identified weight loss as the most important PEI symptom, and indicative of disease severity. Clinicians reported patients’ diet (n1⁄410) and social lives (n1⁄43) to be impacted by PEI. There were concerns about treatment adherence amongst adolescents with CF, and CP patients who continued to consume alcohol. Conclusion: Reliance on clinical signs and symptoms for diagnosis of PEI suggests a need for a specific tool to screen for symptoms in a standardized and reliable way. Adherence concerns indicate a need for a tool to aid clinician-patient communication and disease management. O-33 Abstract id: 316. Disruption of fractalkine/CX3CR1 signalling attenuates pancreatic pain in experimental chronic pancreatitis Jan G. D’Haese , Tom D. D’Haese , Hamza Sezgin , Timo Kehl , Ihsan Ekin Demir , Frank Bergmann , Helmut Friess , G€ uralp O. Ceyhan . Department of Surgery, Klinikum rechts der Isar, Technische Universit€at M€ unchen, Germany Department of Pathology, Universit€atsklinikum Heidelberg, Universit€at Heidelberg, Germany Introduction: Chronic pancreatitis (CP) is a chronic inflammatory condition of the pancreas leading to severe pain and fibrosis. Fractalkine is a chemokine that chemoattracts inflammatory cells through its highly selective receptor CX3CR1 and has been suggested to aggravate pancreatic inflammation. Fractalkine is moreover known to be expressed on spinal neurons and sensory afferents where it has shown major pain-modulatory effects in different experimental pain states. Aims: We aimed to investigate the course of experimental chronic pancreatitis in CX3CR1-/deficient mice and the potential therapeutic implications of a CX3CR1 small molecule inhibitor. Materials & methods: CP was induced in CX3CR1-knockout and wildtype mice by repetitive intraperitoneal cerulein injections. Treatment groups received an orally available small molecule CX3CR1 inhibitor. Hyperalgesia was assessed by systematic behavioural observation, locomotion analysis, and measurement of abdominal mechanical sensitivity. Pancreatic tissue was harvested after sacrifice for further analyses. Results: Both CX3CR1-knockout and CX3CR1-blocking treated mice showed significantly less pain related behaviour (p < 0.0001) and significantly less weight loss (p < 0.01) when compared to their wild-type controls, with a clear dose-response correlation in the treated mice. This reduction in pain related behaviour was confirmed in IHC andWB analysis of pain markers. Unexpectedly, there was no difference in inflammatory cell infiltrations, fibrosis, Amylase/Lipase levels, and Trypsin/MPO activity. Conclusion: Fractalkine/CX3CR1 signalling seems to be crucial in initiating chronic pancreatic hyperalgesia. It does however not seem to have a direct effect on inflammatory cell infiltration and fibrosis. Nevertheless, these novel findings reveal CX3CR1 as a promising new target for the treatment of chronic pancreatic pain. O-34 Abstract id: 215. The development of fibrosis in a novel model of chronic pancreatitis is mediated by complement factor C5 Matthias Sendler , Georg Beyer , Vivien Kauschke , Sandrina Maertin , Thomas Wartmann , Frank Ulrich Weiss , Walter Halangk , Markus M. Lerch , Julia Mayerle . Department of Medicine A, University Medicine, Ernst-Moritz-ArndtUniversity Greifswald, Germany Division of Experimental Surgery, Otto-von-Guericke-University Magdeburg, Germany Introduction: Chronic pancreatitis is accompanied with the loss of exocrine function and the development of fibrosis. Aims:We investigate the effect of complement factor 5 (C5) in a newly established murine model of chronic pancreatitis and compared it to repetitive caerulein injections. Materials & methods: Chronic pancreatitis was induced in C5þ/þ and C5-/mice by ligation of the pancreatic duct in the body of the organ (leaving the head unaffected) and a single supramaximal caerulein injection. Animals were sacrificed 21 days after ligation. As a second model we used repetitive supramaximal caerulein stimulation over 10 weeks. We used serum amylase and lipase as markers for pancreatic damage, collagen as a marker for fibrosis and histology for morphological evaluation. Isolated pancreatic stellate cells (PSCs) were stimulated with C5a in vitro. 13 (2013) S2–S98 S13 Abstracts / Pancreatology 13 (2013) S2–S98 S14s / Pancreatology 13 (2013) S2–S98 S14 Results: Pancreatic damage in the initial phase was comparable in both animal strains. In contrast to the early phase, C5-/mice displayed reduced pancreatic fibrosis in both models. Histology showed decreased collagen I and a smooth muscle actin (aSMA) staining. Also the amount of Ki67 positive cells was decreased in C5-deleted animals. In pancreatic tissue of wild type animalswith chronic pancreatitis C5a receptor and aSMApositive PSCs were observed by fluorescence staining. Isolated PSCs could be activated with C5a showing increased aSMA expression and decreased proliferation. Conclusion: C5 is an important regulator for the development of pancreatic fibrosis during chronic pancreatitis, but does not contribute to the severity of the disease during the acute phase. C5a has direct effects on fibrosis by activating PSCs.

BACKGROUND Osteoporosis is diagnosed by bone loss using a radiological parameter called T-score. Preclinical studies use DXA to evaluate bone status were the T-score is referenced on bone mineral density (BMD) values of the same animals before treatment. Clinically, the reference BMD represents values of an independent group of healthy patients around 30 years old. The present study established a clinically similar T-score standard to diagnose osteoporosis in a sheep model. MATERIAL AND METHODS We used 31 female merino land sheep (average 5.5 years old) to study osteoporosis. The following groups were compared using DXA measurement: 1) control; 2) ovariectomized (OVX); 3) OVX combined with a deficient diet (OVXD); and 4) OVXD combined with methylprednisolone administration (OVXDS). Further, an independent group of 32 healthy sheep (4-6 years old) were measured as an independent baseline. BMD was measured at 0 months, 3 months, and 8 months after treatment. RESULTS The same significance pattern between the treated groups and either baseline groups was seen. However, using an independent baseline changed the "clinical" interpretation of the data from an osteoporotic bone status (T-score