Search

Increased incidence of bone fractures in the elderly is associated with gradual sarcopenia. Similar deterioration of bone quality is seen with prolonged bed rest, spinal cord injuries or in astronauts exposed to microgravity and, preceded by loss of muscle mass. Signaling mechanisms involving uridine-5'-triphosphate (UTP) regulate bone homeostasis

International audience; Transgenic and knockout animal models are widely used to investigate the role of receptors, signaling pathways, and other peptides and proteins. Varying results are often published on the same model from different groups, and much effort has been put into understanding the underlying causes of these sometimes conflicting results. Recently, it has been shown that a P2X4R knockout model carries a so-called passenger mutation in the P2X7R gene, potentially affecting the interpretation of results from studies using this animal model. We therefore report this case to raise awareness about the potential pitfalls using genetically modified animal models, especially within P2 receptor research. Although purinergic signaling has been recognized as an important contributor to the regulation of bone remodeling, the process that maintains the bone quality during life, little is known about the role of the P2X4 receptor (P2X4R) in regulation of bone remodeling in health and disease. To address this, we analyzed the bone phenotype of P2rx4tm1Rass (C57BL/6J) knockout mice and corresponding wildtype using microCT and biomechanical testing. Overall, we found that the P2X4R knockout mice displayed improved bone microstructure and stronger bones in an age- and gender-dependent manner. While cortical BMD, trabecular BMD, and bone volume were higher in the 6-month-old females and 3-month-old males, this was not the case for the 3-month-old females and the 6-month-old males. Bone strength was only affected in the females. Moreover, we found that P2X4R KO mice carried the P2X7 receptor 451P wildtype allele, whereas the wildtype mice carried the 451L mutant allele. In conclusion, this study suggests that P2X4R could play a role in bone remodeling, but more importantly, it underlines the potential pitfalls when using knockout models and highlights the importance of interpreting results with great caution. Further studies are needed to verify any specific effects of P2X4R on bone metabolism.

Exercise is recommended as first‐line treatment to reduce pain and improve physical function in patients with hip osteoarthritis, but the mechanism behind the effect remains unknown. Blood and urine were collected at baseline and after 4 months of exercise from 60+‐year‐old persons (n = 39) with hip osteoarthritis included in a randomized controlled trial comparing the effects of strength training (ST), Nordic Walking (NW), and unsupervised home‐based exercise (control). We measured biomarkers of bone (N‐terminal propeptide of type I collagen, C‐telopeptide of type I collagen, sclerostin, receptor activator of nuclear factor kappa‐B ligand, and osteoprotegerin) and cartilage (C‐telopeptide of type II collagen (CTX‐II), cartilage oligomeric matrix protein, and N‐terminal propeptide of type III collagen). Sclerostin levels decreased independent of the type of training. There was significant interaction between type of training and change in CTX‐II level. When combining the supervised groups (NW and ST), both CTX‐II and sclerostin level were decreased in the supervised training group, while CTX‐II and sclerostin were unchanged in the control group. In conclusion, CTX‐II and sclerostin level were reduced by 4 months of supervised training, suggesting that certain types of exercise affect cartilage and bone, potentially contributing to beneficial effects of exercise in patients.

ENIGMA-CNV working group., Low-frequency 1q21.1 distal deletion and duplication copy number variant (CNV) carriers are predisposed to multiple neurodevelopmental disorders, including schizophrenia, autism and intellectual disability. Human carriers display a high prevalence of micro- and macrocephaly in deletion and duplication carriers, respectively. The underlying brain structural diversity remains largely unknown. We systematically called CNVs in 38 cohorts from the large-scale ENIGMA-CNV collaboration and the UK Biobank and identified 28 1q21.1 distal deletion and 22 duplication carriers and 37,088 non-carriers (48% male) derived from 15 distinct magnetic resonance imaging scanner sites. With standardized methods, we compared subcortical and cortical brain measures (all) and cognitive performance (UK Biobank only) between carrier groups also testing for mediation of brain structure on cognition. We identified positive dosage effects of copy number on intracranial volume (ICV) and total cortical surface area, with the largest effects in frontal and cingulate cortices, and negative dosage effects on caudate and hippocampal volumes. The carriers displayed distinct cognitive deficit profiles in cognitive tasks from the UK Biobank with intermediate decreases in duplication carriers and somewhat larger in deletion carriers—the latter potentially mediated by ICV or cortical surface area. These results shed light on pathobiological mechanisms of neurodevelopmental disorders, by demonstrating gene dose effect on specific brain structures and effect on cognitive function., 1000BRAINS: The 1000BRAINS study was funded by the Institute of Neuroscience and Medicine, Research Center Juelich, Germany. We thank the Heinz Nixdorf Foundation (Germany) for the generous support of the Heinz Nixdorf Recall Study on which 1000BRAINS is based. We also thank the scientists and the study staff of the Heinz Nixdorf Recall Study and 1000BRAINS. Funding was also granted by the Initiative and Networking Fund of the Helmholtz Association (Caspers) and the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement 945539 (Human Brain Project SGA3; Amunts, Caspers, Cichon). Brainscale: The Brainscale study was supported by the Netherlands Organization for Scientific Research MagW 480-04-004 (Dorret I. Boomsma), 51.02.060 (Hilleke E. Hulshoff Pol), 668.772 (Dorret I. Boomsma and Hilleke E. Hulshoff Pol); NWO/SPI 56-464-14192 (Dorret I. Boomsma), the European Research Council (ERC-230374) (Dorret I. Boomsma), High Potential Grant Utrecht University (Hilleke E.Hulshoff Pol) and NWO Brain and Cognition 433-09-220 (Hilleke E.Hulshoff Pol). Betula: The Betula study was funded by the Knut and Alice Wallenberg (KAW) foundation (Nyberg). The Freesurfer segmentations on the Betula sample were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at HPC2N (in Umeå, Sweden), partially funded by the Swedish Research Council through grant agreement no. 2018-05973. Brain Imaging Genetics (BIG): This work makes use of the BIG database, first established in Nijmegen, The Netherlands, in 2007. This resource is now part of Cognomics (www.cognomics.nl), a joint initiative by researchers from the Donders Centre for Cognitive Neuroimaging, the Human Genetics and Cognitive Neuroscience departments of the Radboud University Medical Centre and the Max Planck Institute for Psycholinguistics in Nijmegen. The Cognomics Initiative has received support from the participating departments and centres and from external grants, that is, the Biobanking and Biomolecular Resources Research Infrastructure (Netherlands) (BBMRI-NL), the Hersenstichting Nederland and the Netherlands Organization for Scientific Research (NWO). The research leading to these results also receives funding from the NWO Gravitation grant ‘Language in Interaction’, the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement nos. 602450 (IMAGEMEND), 278948 (TACTICS) and 602805 (Aggressotype), as well as from the European Community’s Horizon 2020 programme under grant agreement no. 643051 (MiND) and from ERC-2010-AdG 268800-NEUROSCHEMA. In addition, the work was supported by a grant for the ENIGMA Consortium (grant number U54 EB020403) from the BD2K Initiative of a cross-NIH partnership. deCODE genetics: deCODE genetics acknowledges support from the Innovative Medicines Initiative Joint Undertaking under grant agreement nos. 115008 (NEWMEDS) and 115300 (EUAIMS), of which resources are composed of EFPIA in-kind contribution and financial contribution from the European Union’s Seventh Framework Programme (EU-FP7/2007-2013), EU-FP7-funded grant agreement no. 602450 (IMAGEMEND) and EU-funded FP7-People-2011-IAPP grant agreement no. 286213 (PsychDPC). Dublin: This work was supported by Science Foundation Ireland (SFI grant 12/IP/1359 to Gary Donohoe and grant SFI08/IN.1/B1916-Corvin to Aidan C. Corvin). ECHO-DEFINE: The ECHO study acknowledges funding from a Medical Research Council (MRC) Centre Grant to Michael J. Owen (G0801418), the Wellcome Trust (Institutional Strategic Support Fund (ISSF) to van den Bree and Clinical Research Training Fellowship to Joanne L. Doherty), the Waterloo Foundation (WF 918-1234 to van den Bree), the Baily Thomas Charitable Fund (2315/1 to van den Bree), National Institute of Mental Health (NIMH 5UO1MH101724 to van den Bree and Michael J. Owen), the IMAGINE-2 study (funded by the MRC (MR/T033045/1) to van den Bree, Jeremy Hall and Michael J. Owen), the IMAGINE-ID study (funded by MRC (MR/N022572/1) to Jeremy Hall, van den Bree and Owen). The DEFINE study was supported by a Wellcome Trust Strategic Award (100202/Z/12/Z) to Michael J. Owen. ENIGMA: ENIGMA is supported in part by NIH grants U54 EB20403, R01MH116147 and R56AG058854. NIA T32AG058507; NIH/NIMH 5T32MH073526. EPIGEN-Dublin: The EPIGEN-Dublin cohort was supported by a Science Foundation Ireland Research Frontiers Programme award (08/RFP/GEN1538). EPIGEN-UK (Sisodiya): The work was partly undertaken at UCLH/UCL, which received a proportion of funding from the UK Department of Health’s NIHR Biomedical Research Centres funding scheme. We are grateful to the Wolfson Trust and the Epilepsy Society for supporting the Epilepsy Society MRI scanner. GAP: This work was supported by the National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and the Institute of Psychiatry, Psychology and Neuroscience, King’s College London. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. GOBS: The GOBS study data collection was supported in part by the National Institutes of Health (NIH) grants: R01 MH078143, R01 MH078111 and R01 MH083824, with work conducted in part in facilities constructed under the support of NIH grant C06 RR020547. GSP: Data were in part provided by the Brain Genomics Superstruct Project (GSP) of Harvard University and Massachusetts General Hospital (MGH) (Principal Investigators: Randy Buckner, Jordan Smoller and Joshua Roffman), with support from the Center for Brain Science Neuroinformatics Research Group, Athinoula A. Martinos Center for Biomedical Imaging, Center for Genomic Medicine and Stanley Center for Psychiatric Research. Twenty individual investigators at Harvard and MGH generously contributed data to the overall project. We would like to thank Randy Buckner for insightful comments and feedback on this work. HUBIN: The HUBIN study was financed by the Swedish Research Council (K2010-62X-15078-07-2, K2012-61X-15078-09-3, 521-2014-3487 K2015-62X-15077-12-3, 2017-00949), the regional agreement on medical training and clinical research between Stockholm County Council and the Karolinska Institutet. HUNT: The HUNT study is a collaboration between HUNT Research Centre (Faculty of Medicine and Movement Sciences, NTNU—Norwegian University of Science and Technology), Nord-Trøndelag County Council, Central Norway Health Authority and the Norwegian Institute of Public Health. HUNT-MRI was funded by the Liaison Committee between the Central Norway Regional Health Authority and the Norwegian University of Science and Technology, and the Norwegian National Advisory Unit for functional MRI. IMAGEN: This work received support from the following sources: the European Union-funded FP6 Integrated Project IMAGEN (reinforcement-related behaviour in normal brain function and psychopathology) (LSHM-CT- 2007-037286), the Horizon 2020 funded ERC Advanced Grant ‘STRATIFY’ (Brain network based stratification of reinforcement-related disorders) (695313), ERANID (Understanding the Interplay between Cultural, Biological and Subjective Factors in Drug Use Pathways) (PR-ST-0416-10004), BRIDGET (JPND: BRain Imaging, cognition Dementia and next generation GEnomics) (MR/N027558/1), Human Brain Project (HBP SGA 2, 785907),the FP7 projects IMAGEMEND(602450; IMAging GEnetics for MENtal Disorders) and MATRICS (603016), the Innovative Medicine Initiative Project EUAIMS (115300-2), the Medical Research Council Grant ‘c-VEDA’ (Consortium on Vulnerability to Externalizing Disorders and Addictions) (MR/N000390/1), the Swedish Research Council FORMAS, the Medical Research Council, the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London, the Bundesministeriumfür Bildung und Forschung (BMBF grants 01GS08152, 01EV0711; eMED SysAlc01ZX1311A; Forschungsnetz AERIAL 01EE1406A, 01EE1406B), the Deutsche Forschungsgemeinschaft (DFG grants, SM 80/7-2, SFB 940/2), the Medical Research Foundation and Medical Research Council (grants MR/R00465X/1 and MR/S020306/1). Further support was provided by grants from: ANR (project AF12-NEUR0008-01—WM2NA, ANR-12-SAMA-0004), the Eranet Neuron (ANR-18-NEUR00002-01), the Fondation de France (00081242), the Fondation pour la Recherche Médicale (DPA20140629802), the Mission Interministérielle de Lutte-contre-les-Drogues-et-les-Conduites-Addictives (MILDECA), the Assistance-Publique-Hôpitaux-de-Paris and INSERM (interface grant), Paris Sud University IDEX 2012, the Fondation de l’Avenir (grant AP-RM-17-013), the Fédération pour la Recherche sur le Cerveau; the National Institutes of Health, Science Foundation Ireland (16/ERCD/3797), USA (Axon, Testosterone and Mental Health during Adolescence; RO1 MH085772-01A1) and by NIH Consortium grant U54 EB020403, supported by a cross-NIH alliance that funds Big Data to Knowledge Centres of Excellence. Lifespan: The study is funded by the Research Council of Norway (230345, 288083 and 223273). NCNG: NCNG sample collection was supported by grants from the Bergen Research Foundation and the University of Bergen, the Dr Einar Martens Fund, the Research Council of Norway, to le Hellard, Steen and Espeseth. The Bergen group was supported by grants from the Western Norway Regional Health Authority (Grant 911593 to Arvid Lundervold, Grant 911397 and 911687 to Astri Johansen Lundervold). NTR: The NTR cohort was supported by the Netherlands Organization for Scientific Research (NWO) and The Netherlands Organisation for Health Research and Development (ZonMW) grants 904-61-090, 985-10-002, 912-10-020, 904-61-193, 480-04-004,463-06-001, 451-04-034, 400-05-717, Addiction-31160008, 016-115-035, 481-08-011, 056-32-010, Middelgroot-911-09-032, OCW_NWO Gravity programme—024.001.003, NWO-Groot 480-15-001/674, Center for Medical Systems Biology (CSMB, NWO Genomics), NBIC/BioAssist/RK(2008.024), Biobanking and Biomolecular Resources Research Infrastructure (BBMRI-NL, 184.021.007 and 184.033.111); Spinozapremie (NWO-56-464-14192), KNAW Academy Professor Award (PAH/6635) and University Research Fellow grant (URF) to Dorret I. Boomsma; Amsterdam Public Health research institute (former EMGO+), Neuroscience Amsterdam research institute (former NCA); the European Science Foundation (ESF, EU/QLRT-2001-01254), the European Community’s Seventh Framework Programme (FP7- HEALTH-F4-2007-2013, grant 01413: ENGAGE and grant 602768: ACTION); the European Research Council (ERC Starting 284167, ERC Consolidator 771057, ERC Advanced 230374), Rutgers University Cell and DNA Repository (NIMH U24 MH068457-06), the National Institutes of Health (NIH, R01D0042157-01A1, R01MH58799-03, MH081802, DA018673, R01 DK092127-04, Grand Opportunity grants 1RC2 MH089951 and 1RC2 MH089995); the Avera Institute for Human Genetics, Sioux Falls, South Dakota (USA). Part of the genotyping and analyses were funded by the Genetic Association Information Network (GAIN) of the Foundation for the National Institutes of Health. Computing was supported by NWO through grant 2018/EW/00408559, BiG Grid, the Dutch e-Science Grid and SURFSARA. OATS: The OATS study has been funded by a National Health & Medical Research Council (NHMRC) and Australian Research Council (ARC) Strategic Award Grant of the Ageing Well, Ageing Productively Programme (ID No. 401162) and NHMRC Project Grants (ID Nos. 1045325 and 1085606). This research was facilitated through Twins Research Australia, a national resource in part supported by an NHMRC Centre for Research Excellence Grant (ID No.: 1079102). We thank the participants for their time and generosity in contributing to this research. We acknowledge the contribution of the OATS research team (https://cheba.unsw.edu.au/project/older-australian-twins-study) to this study. OATS genotyping was partly funded by a Commonwealth Scientific and Industrial Research Organization Flagship Collaboration Fund Grant. Osaka: Osaka study was supported by the Brain Mapping by Integrated Neurotechnologies for Disease Studies (Brain/MINDS: Grant Number JP18dm0207006), Brain/MINDS& beyond studies (Grant Number JP20dm0307002) and Health and Labour Sciences Research Grants for Comprehensive Research on Persons with Disabilities (Grant Number JP20dk0307081) from the Japan Agency for Medical Research and Development (AMED), Grants-in-Aid for Scientific Research (KAKENHI; Grant Numbers JP25293250 and JP16H05375). Some computations were performed at the Research Center for Computational Science, Okazaki, Japan. PAFIP: The PAFIP study was supported by Instituto de Salud Carlos III, FIS 00/3095, 01/3129, PI020499, PI060507, PI10/00183, the SENY Fundació Research Grant CI2005-0308007 and the FundaciónMarqués de Valdecilla API07/011. Biological samples from our cohort were stored at the Valdecilla Biobank and genotyping services were conducted at the Spanish ‘Centro Nacional de Genotipado’ (CEGEN-ISCIII). MCIC/COBRE: The study is funded by the National Institutes of Health studies R01EB006841, P20GM103472 and P30GM122734 and Department of Energy DE-FG02-99ER62764. PING: Data collection and sharing for the Paediatric Imaging, Neurocognition and Genetics (PING) Study (National Institutes of Health Grant RC2DA029475) were funded by the National Institute on Drug Abuse and the Eunice Kennedy Shriver National Institute of Child Health & Human Development. A full list of PING investigators is at http://pingstudy.ucsd.edu/investigators.html. QTIM: The QTIM study was supported by the National Institute of Child Health and Human Development (R01 HD050735) and the National Health and Medical Research Council (NHMRC 486682, 1009064), Australia. Genotyping was supported by NHMRC (389875). Medland is supported in part by an NHMRC fellowship (APP1103623). SHIP: SHIP is part of the Community Medicine Research net of the University of Greifswald, Germany, which is funded by the Federal Ministry of Education and Research (grant nos. 01ZZ9603, 01ZZ0103 and 01ZZ0403), the Ministry of Cultural Affairs and the Social Ministry of the Federal State of Mecklenburg-West Pomerania. Genome-wide single-nucleotide polymorphism typing in SHIP and MRI scans in SHIP and SHIP-TREND have been supported by a joint grant from Siemens Healthineers, Erlangen, Germany and the Federal State of Mecklenburg-West Pomerania. StrokeMRI: StrokeMRI was supported by the Norwegian ExtraFoundation for Health and Rehabilitation(2015/FO5146), the Research Council of Norway (249795, 262372), the South-Eastern Norway Regional Health Authority (2014097, 2015044, 2015073) and the Department of Psychology, University of Oslo. Sydney MAS: The Sydney Memory and Aging Study (Sydney MAS) is funded by National and HealthMedical Research Council (NHMRC) Programme and Project Grants (ID350833, ID568969 and ID109308). We also thank the Sydney MAS participants and the Research Team. SYS: The SYS Study is supported by Canadian Institutes of Health Research. TOP: Centre of Excellence: RCN #23273 and RCN #226971. Part of this work was performed on the TSD (Tjeneste for Sensitive Data) facilities, owned by the University of Oslo, operated and developed by the TSD service group at the University of Oslo, IT-Department (USIT) (tsd-drift@usit.uio.no). The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7-PEOPLE-2013-COFUND) under grant agreement no. 609020—Scientia Fellows; the Research Council of Norway (RCN) #276082—A lifespan perspective on mental illness: toward precision medicine using multimodal brain imaging and genetics. Ida E. Sønderby and Rune Bøen are supported by South-Eastern Norway Regional Health Authority (#2020060). Ida E. Sønderby and Ole A. Andreassen have received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant agreement no. 847776 (CoMorMent project) and the KG Jebsen Foundation (SKGJ-MED-021). UCLA_UMCU: The UCLA_UMCU cohort comprises of six studies which were supported by National Alliance for Research in Schizophrenia and Affective Disorders (NARSAD) (20244 to Prof. Hillegers), The Netherlands Organisation for Health Research and Development (ZonMw) (908-02-123 to Prof. Hulshoff Pol), and Netherlands Organisation for Scientific Research (NWO 9120818 and NWO-VIDI 917-46-370 to Prof. Hulshoff Pol). The GROUP study was funded through the Geestkracht programme of the Dutch Health Research Council (ZonMw, grant number 10-000-1001), and matching funds from participating pharmaceutical companies (Lundbeck, AstraZeneca, Eli Lilly and Janssen Cilag) and universities and mental health care organizations (Amsterdam: Academic Psychiatric Centre of the Academic Medical Center and the mental health institutions: GGZ inGeest, Arkin, Dijk en Duin, GGZ Rivierduinen, Erasmus Medical Centre, GGZ Noord-Holland-Noord. Groningen: University Medical Center Groningen and the mental health institutions: Lentis, GGZ Friesland, GGZ Drenthe, Dimence, Mediant, GGNet Warnsveld, Yulius Dordrecht and Parnassia Psycho-medical Center, The Hague. Maastricht: Maastricht University Medical Centre and the mental health institutions: GGzE, GGZ Breburg, GGZ Oost-Brabant, Vincent van Gogh, voor Geestelijke Gezondheid, Mondriaan, Virenzeriagg, Zuyderland GGZ, MET ggz, Universitair Centrum Sint-JozefKortenberg, CAPRI University of Antwerp, PC Ziekeren Sint-Truiden, PZ Sancta Maria Sint-Truiden, GGZ Overpelt, OPZ Rekem. Utrecht: University Medical Center Utrecht and the mental health institutions: Altrecht, GGZ Centraal and Delta.). UK Biobank: This work made use of data sharing from UK Biobank (under project code 27412). Others: Work by Pierre Vanderhaeghen was funded by Grants of the European Research Council (ERC Adv Grant GENDEVOCORTEX), the EOS Programme, the Belgian FWO, the AXA Research Fund and the Belgian Queen Elizabeth Foundation. Ikuo K. Suzuki was supported by a postdoctoral fellowship of the FRS/FNRS.

Background: Metabolic bone disease and fractures are a great problem for patients with epilepsy. The use of antiepileptic drugs (AEDs) is known to play an essential role in the progression of bone loss by various pathophysiological mechanisms. The aim of this study was to evaluate the effects of AEDs on bone microstructure as an additional cause of an increased fracture risk in patients with epilepsy. Methods: Five groups of each of 12 female rats were orally dosed daily for 8 weeks with either carbamazepine (CBZ) (60 mg/kg), eslicarbazepine (ESL) (80 mg/kg), valproic acid (VPA) (300 mg/kg), levetiracetam (LEV) (50 mg/kg) or saline (control (CTL)). Following killing, dissected femurs were analyzed using X-ray micro-computed tomography (µCT), dual-energy X-ray absorptiometry (DXA) and biomechanical testing. In addition, serum bone turnover markers (BTM) were monitored throughout the experiment. Results: Compared to CTL treatment, VPA decreased bone volume fraction by 19%, decreased apparent density by 14% and increased structural model index by 41%. No changes were observed in bone biomechanics nor mineral density evaluated by DXA or in levels of BTM. Conclusions: Our findings suggest that VPA affects the microarchitectural properties of the bone. The AEDs CBZ, ESL and LEV appear to have less adverse effects on bone biology and may be a better choice when treating patients with respect to bone health.

The ATP-gated receptor P2X7 (P2X7R) is involved in regulation of cell survival and has been of interest in cancer field. Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer and new markers and therapeutic targets are needed. PDAC is characterized by a complex tumour microenvironment, which includes cancer and pancreatic stellate cells (PSCs), and potentially high nucleotide/side turnover. Our aim was to determine P2X7R expression and function in human pancreatic cancer cells in vitro as well as to perform in vivo efficacy study applying P2X7R inhibitor in an orthotopic xenograft mouse model of PDAC. In the in vitro studies we show that human PDAC cells with luciferase gene (PancTu-1 Luc cells) express high levels of P2X7R protein. Allosteric P2X7R antagonist AZ10606120 inhibited cell proliferation in basal conditions, indicating that P2X7R was tonically active. Extracellular ATP and BzATP, to which the P2X7R is more sensitive, further affected cell survival and confirmed complex functionality of P2X7R. PancTu-1 Luc migration and invasion was reduced by AZ10606120, and it was stimulated by PSCs, but not by PSCs from P2X7(-/-) animals. PancTu-1 Luc cells were orthotopically transplanted into nude mice and tumour growth was followed noninvasively by bioluminescence imaging. AZ10606120-treated mice showed reduced bioluminescence compared to saline-treated mice. Immunohistochemical analysis confirmed P2X7R expression in cancer and PSC cells, and in metaplastic/neoplastic acinar and duct structures. PSCs number/activity and collagen deposition was reduced in AZ10606120-treated tumours.

Osteocytes are considered the primary mechanosensors of bone, but the signaling pathways they apply in mechanotransduction are still incompletely investigated and characterized. A growing body of data strongly indicates that P2 receptor signaling among osteoblasts and osteoclasts has regulatory effects on bone remodeling. Therefore, we hypothesized that ATP signaling is also applied by osteocytes in mechanotransduction. We applied a short fluid pulse on MLO-Y4 osteocyte-like cells during real-time detection of ATP and demonstrated that mechanical stimulation activates the acute release of ATP and that these acute ATP signals are fine-tuned according to the magnitude of loading. ATP release was then challenged by pharmacological inhibitors, which indicated a vesicular release pathway for acute ATP signals. Finally, we showed that osteocytes express functional P2X2 and P2X7 receptors and respond to even low concentrations of nucleotides by increasing intracellular calcium concentration. These results indicate that in osteocytes, vesicular ATP release is an acute mediator of mechanical signals and the magnitude of loading. These and previous results, therefore, implicate purinergic signaling as an early signaling pathway in osteocyte mechanotransduction.

Parathyroid hormone (PTH) and PTH(1-34) have been shown to promote bone healing in several animal studies. It is known that the mechanical environment is important in fracture healing. Furthermore, PTH and mechanical loading has been suggested to have synergistic effects on intact bone. The aim of the present study was to investigate whether the effect of PTH(1-34) on fracture healing in rats was influenced by reduced mechanical loading. For this purpose, we used female, 25-week-old ovariectomized rats. Animals were subjected to closed midshaft fracture of the right tibia 10 weeks after ovariectomy. Five days before fracture, half of the animals received Botulinum Toxin A injections in the muscles of the fractured leg to induce muscle paralysis (unloaded group), whereas the other half received saline injections (control group). For the following 8 weeks, half of the animals in each group received injections of hPTH(1-34) (20 µg/kg/day) and the other half received vehicle treatment. Fracture healing was assessed by radiology, dual-energy X-ray absorptiometry (DXA), histology, and bone strength analysis. We found that unloading reduced callus area significantly, whereas no effects of PTH(1-34) on callus area were seen in neither normally nor unloaded animals. PTH(1-34) increased callus bone mineral density (BMD) and bone mineral content (BMC) significantly, whereas unloading decreased callus BMD and BMC significantly. PTH(1-34) treatment increased bone volume of the callus in both unloaded and control animals. PTH(1-34) treatment increased ultimate force of the fracture by 63% in both control and unloaded animals and no interaction of the two interventions could be detected. PTH(1-34) was able to stimulate bone formation in normally loaded as well as unloaded intact bone. In conclusion, the study confirms the stimulatory effect of PTH(1-34) on fracture healing, and our data suggest that PTH(1-34) is able to promote fracture healing, as well as intact bone formation during conditions of reduced mechanical loading. © 2013 American Society for Bone and Mineral Research.

Fracture healing is a complex process, and a significant number of fractures are complicated by impaired healing and non-union. Impaired healing is prevalent in certain risk groups, such as the elderly, osteoporotics, people with malnutrition, and women after menopause. Currently, no pharmacological treatments are available. There is therefore an unmet need for medications that can stimulate bone healing. Parathyroid hormone (PTH) is the first bone anabolic drug approved for the treatment of osteoporosis, and intriguingly a number of animal studies suggest that PTH could be beneficial in the treatment of fractures and could thus be a potentially new treatment option for induction of fracture healing in humans. Furthermore, fractures in animals with experimental conditions of impaired healing such as aging, estrogen withdrawal, and malnutrition can heal in an expedited manner after PTH treatment. Interestingly, fractures occurring at both cancellous and cortical sites can be treated successfully, indicating that both osteoporotic and nonosteoporotic fractures can be the target of PTH-induced healing. Finally, the data suggest that PTH partly prevents the delay in fracture healing caused by aging. Recently, the first randomized, controlled clinical trial investigating the effect of PTH on fracture healing was published, indicating a possible clinical benefit of PTH treatment in inducing fracture healing. The aim of this article is therefore to review the evidence for the potential of PTH in bone healing, including the underlying mechanisms for this, and to provide recommendations for the clinical testing and use of PTH in the treatment of impaired fracture healing in humans.

Bone is a highly dynamic organ, being constantly modeled and remodeled in order to adapt to the changing need throughout life. Bone turnover involves the coordinated actions of bone formation and bone degradation. Over the past decade great effort has been put into the examination of how P2X receptors regulate bone metabolism and especially for the P2X7 receptor an impressive amount of evidence has now documented its expression in osteoblasts, osteoclasts, and osteocytes as well as important functional roles in proliferation, differentiation, and function of the cells of bone. Key evidence has come from studies on murine knockout models and from pharmacologic studies on cells and animals. More recently, the role of P2X receptors in human bone diseases has been documented. Loss-of-functions polymorphisms in the P2X7 receptorare associated with bone loss and increased fracture risk. Very recently a report from a genetic study in multiple myeloma demonstrated that decreased P2X7 receptor function was associated with increased risk of developing multiple myeloma. In contrast, the risk of developing myeloma bone disease and subsequent vertebral fractures was increased in subjects carrying P2X7 receptor gain-of-function alleles as compared to subjects only carrying loss-of-function or normal functioning alleles. It is evident that P2X receptors are important in regulating bone turnover and maintaining bone mass, and thereby holding great potential as novel drug targets for treatment of bone diseases. However, further research is needed before we fully understand the roles and effects of P2X receptors in bone.

Teriparatide (Parathyroid hormone (PTH) 1-34) has been shown to increase bone mineral density (BMD) and reduce the risk of vertebral fractures when given intermittently. In contrast primary hyperparathyroidism (PHPT) is associated with increased bone loss. Moreover an increased occurrence of cardiovascular disease (CVD) is seen in PHPT patients. The N-terminal fragment of the pro-peptide of Brain Natriuretic peptide (NT-proBNP), a risk marker of CVD, has been shown to be elevated in PHPT patients, indicating that continuously high concentrations of PTH affect the heart. Therefore the aim of this study was to investigate whether teriparatide treatment is associated with changes in plasma NT-proBNP.A total of 42 patients receiving teriparatide treatment were included in the study. Blood samples were taken at baseline, and after 1, 3 and 6 months of treatment. Plasma concentrations of NT-proBNP were measured. Plasma concentrations of ionized calcium, PTH and alkaline phosphatase (ALP) were also analyzed, and BMD for the lumbar spine and total hip was recorded at baseline and after 6 months.Data from 10 men and 32 women, mean age 68 years, were included in the analysis. No effect of teriparatide on plasma concentrations of NT-proBNP was observed at any time points. Ionized calcium and ALP concentrations in the plasma increased after 6 months of treatment, whereas PTH concentrations decreased. Spine BMD T-score was significantly increased after 6 months of treatment.After 6 months of treatment with teriparatide, it did not change the concentration of NT-proBNP in plasma, suggesting that intermittent exposure to therapeutic levels of teriparatide does not affect heart function.

Amylin(1-8), a cyclic peptide consisting of the eight N-terminal amino acids of the 37-amino acid peptide amylin, has been shown to induce proliferation of primary osteoblasts and to induce bone formation in healthy male mice, whereas no data on efficacy in bone disease-related models have been reported. Therefore, we evaluated any effects of amylin(1-8) in ovariectomized rats with established osteopenia, a model for postmenopausal osteoporosis. At doses up to 100 nmol/kg/day, a dose highly effective in healthy mice, amylin(1-8) was unable to increase bone mineral density in ovariectomized rats during an 8-week treatment period. Histomorphometric analysis of the tibia indicated that amylin(1-8) did not change bone histomorphometric parameters. In an attempt to verify any potential biological effects of amylin(1-8), we investigated the efficacy of this peptide in various in vitro assays. Experiments designed to confirm previously published results on the proliferative effects of amylin(1-8) on primary osteoblasts failed to show any response. Amylin(1-8) was able to partially displace (125)I-rat amylin(1-37) from amylin receptors composed of the calcitonin receptor and RAMP1, indicating specific interaction of the peptide with the amylin binding site. However, in vitro efficacy assays with amylin(1-8) in calcitonin receptor-RAMP-positive HEK293T and MCF7 cells failed to reveal any agonist activity of amylin(1-8), whereas amylin(1-37) showed the expected agonist activity. In conclusion, our results indicate that amylin(1-8) does not show agonist activity on amylin receptors, does not affect osteoblast proliferation, and is devoid of anabolic activity in bone.