Detection of High-Energy Phosphates in Cortical Bone as an Indicator of Bone Healing and Remodelling: Use of a Rabbit Model

Buchholz, J.; Huber, F.-X.; Meeder, P. J.; Muhr, G.; Kreitz, G K; Herzog, L.

doi:10.1177/230949900401200213

Cited by 7 publications

(7 citation statements)

References 11 publications

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“…( 9 ) Extracellular ATP has also been shown to be increased during bone loading, bone fracture, and bone repair. ( 10 ) Once formed, extracellular adenosine can ligate the four known types of specific cell surface P1 adenosine receptors (A1, A2a, A2b, and A3), all of which are members of the G protein‐coupled family of receptors. ( 11 )…”

Section: Introductionmentioning

confidence: 99%

Human Osteoblast Precursors Produce Extracellular Adenosine, Which Modulates Their Secretion of IL-6 and Osteoprotegerin

Evans

Elford

Pexa

et al. 2006

Journal of Bone and Mineral Research

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We showed that human osteoprogenitor cells produced adenosine and expressed ecto-5-nucleotidase and all four adenosine receptor subtypes. Adenosine stimulated IL-6 but inhibited osteoprotegerin secretion, suggesting that adenosine is a newly described regulator of progenitor cell function.Introduction: Maintaining skeletal homeostasis relies on there being a balance between bone formation and resorption; an imbalance between these processes can lead to diseases such as osteoporosis and rheumatoid arthritis. Recent reports showed that locally produced ATP, acting through P2 receptors, has pronounced effects on bone formation. However, ATP can be enzymatically cleaved to adenosine that has little or no activity at P2 receptors but mediates its action through the P1 family of receptors. We studied whether adenosine may also have an important role in controlling bone cell differentiation and function. Materials and Methods: Extracellular adenosine levels were analyzed by high-performance liquid chromatography in HCC1 and bone marrow stromal (BMS) cells. Ecto-5Ј-nucleotidase (CD73) expression and activity was determined by RT-PCR, immunocytochemistry, and the cleavage of etheno-AMP to ethenoadenosine. Adenosine receptor expression and activity were determined by RT-PCR and cAMP measurements. The effects of adenosine receptor agonists on IL-6, osteoprotegerin (OPG), and RANKL expression were determined by ELISA and QRT-PCR. Results: HCC1 and BMS cells produce adenosine and express CD73 and all four adenosine receptor subtypes. The A2b receptor was shown to be functionally dominant in HCC1 cells, as determined by cAMP production and in its stimulation of IL-6 secretion. Adenosine receptor agonism also inhibited OPG secretion and OPG but not RANKL mRNA expression. Conclusions: Our findings show that HCC1 and primary BMS cells produce adenosine, express CD73 and all four adenosine receptor subtypes. In HCC1 cells, adenosine has a potent stimulatory action on IL-6 secretion but an inhibitory action on OPG expression. These data show for the first time that adenosine may be an important regulator of progenitor cell differentiation and hence an important local contributor to the regulation of bone formation and resorption.

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Section: Introductionmentioning

confidence: 99%

Human Osteoblast Precursors Produce Extracellular Adenosine, Which Modulates Their Secretion of IL-6 and Osteoprotegerin

Evans

Elford

Pexa

et al. 2006

Journal of Bone and Mineral Research

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“…After the successful establishment and characterization of GpNLuc-rMSCs, we first evaluated its BLI efficacy in a scaffold-free 3D culture system—MSC spheroids, which is formed using a forced aggregation method. 17,18 It has been demonstrated that MSC spheroid model can effectively maintain and enhance MSC multipotent differentiation potential. 25 After aggregated, rMSCs and GpNLuc-rMSCs spheroids were cultured in osteogenic medium for osteogenic differentiation.…”

Section: Resultsmentioning

confidence: 99%

“…16 Third, unlike commonly used firefly luciferase which is adenosine triphosphate (ATP)-dependent, GpNLuc reporter component NanoLuc is ATP-independent. Since bone healing is very energy consuming and the ATP level has been reported to correlate with the degree of bone repair, 18 being ATP-independent may make GpNLuc reporter a more objective and accurate tool in bone regeneration studies. Thus, following the success in in vivo cancer cell tracing, we herein utilized this novel BRET-based GpNLuc reporter to label MSCs and tested the efficacy of MSC tracking during osteogenic differentiation in vitro and in vivo (rat calvarial critical sized defect (CSD) model), which offered an improved, robust, inexpensive bioluminescent cell tracking strategy for bone tissue engineering.…”

Section: Introductionmentioning

confidence: 99%

Application of bioluminescence resonance energy transfer-based cell tracking approach in bone tissue engineering

et al. 2021

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Bioluminescent imaging (BLI) has emerged as a popular in vivo tracking modality in bone regeneration studies stemming from its clear advantages: non-invasive, real-time, and inexpensive. We recently adopted bioluminescence resonance energy transfer (BRET) principle to improve BLI cell tracking and generated the brightest bioluminescent signal known to date, which thus enables more sensitive real-time cell tracking at deep tissue level. In the present study, we brought BRET-based cell tracking strategy into the field of bone tissue engineering for the first time. We labeled rat mesenchymal stem cells (rMSCs) with our in-house BRET-based GpNLuc reporter and evaluated the cell tracking efficacy both in vitro and in vivo. In scaffold-free spheroid 3D culture system, using BRET-based GpNLuc labeling resulted in significantly better correlation to cell numbers than a fluorescence based approach. In scaffold-based 3D culture system, GpNLuc-rMSCs displayed robust bioluminescence signals with minimal background noise. Furthermore, a tight correlation between BLI signal and cell number highlighted the robust reliability of using BRET-based BLI. In calvarial critical sized defect model, robust signal and the consistency in cell survival evaluation collectively supported BRET-based GpNLuc labeling as a reliable approach for non-invasively tracking MSC. In summary, BRET-based GpNLuc labeling is a robust, reliable, and inexpensive real-time cell tracking method, which offers a promising direction for the technological innovation of BLI and even non-invasive tracking systems, in the field of bone tissue engineering.

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“…The main sources of energy are in the form of adenosine phosphates and, to some extent, cyclic monophosphate, which is converted to adenosine triphosphate (ATP). Buchholz et al [20] performed a study to investigate the correlation of ATP levels between bone metabolisms in the fractured tibiae of rabbit models using high-performance liquid chromatography. The mean ATP concentration in healthy cortical bone was significantly higher than that in the group with delayed healing and muscle-flap coverage.…”

Section: Discussionmentioning

confidence: 99%

The Significance of Serum Phosphate Level on Healing Index and Its Relative Effects in Skeletally Immature and Mature Patients with Hypophosphatemic Rickets

Song

Lee

Jeong

et al. 2014

BioMed Research International

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The aim of this study was to find out the ideal cut-off level of phosphate for safe healing when deformity correction and concomitant lengthening are indicated in the two different skeletal maturity groups of patients with rickets. Thirty-nine hypophosphatemic rickets patients were selected for the study and were divided into two groups: 27 skeletally immature (group IM) and 12 skeletally mature (group M). The outcomes were evaluated with respect to the healing index (HI), laboratory findings, and complications with the mean follow-up of 5.1 years (range, 3.1–7.9). The healing index (HI) of group IM was 1.44 month/cm and HI of group M was 1.68 month/cm. The negative correlation between the level of serum phosphate and HI in group M (coefficient = −0.94) was evaluated to be less than the correlation in group IM (coefficient = −0.50), indicating that the HI is more likely to be affected by serum phosphate in group M than in group IM. Preoperative serum phosphate levels of 2.3 mg/dL and 2.6 mg/dL were analyzed to be the cut-off values of group IM and group M, respectively, in which the cut-off points divided the series into two groups having the most significantly different HI.

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Detection of High-Energy Phosphates in Cortical Bone as an Indicator of Bone Healing and Remodelling: Use of a Rabbit Model

Abstract: Early muscle-flap coverage can revascularise the cortical bone, which is reflected in the higher ATP content in the cortical bone measured by high-performance liquid chromatography. Measuring changes of ATP levels can help investigate the metabolism of the pathological bone.

Cited by 7 publications

References 11 publications

Human Osteoblast Precursors Produce Extracellular Adenosine, Which Modulates Their Secretion of IL-6 and Osteoprotegerin

Human Osteoblast Precursors Produce Extracellular Adenosine, Which Modulates Their Secretion of IL-6 and Osteoprotegerin

Application of bioluminescence resonance energy transfer-based cell tracking approach in bone tissue engineering

The Significance of Serum Phosphate Level on Healing Index and Its Relative Effects in Skeletally Immature and Mature Patients with Hypophosphatemic Rickets

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