The use of autologous enriched bone marrow MSCs to enhance osteoporotic bone defect repair in long-term estrogen deficient goats

Authors

Lei Cao, Guangwang Liu, Yaokai Gan, Qiming Fan, Fei Yang, Xiaoling Zhang, Tingting Tang, Kerong Dai

Abstract

Bone defects are common in elderly patients suffering from osteoporosis. Current methods of bone defect treatment for osteoporosis are not always satisfactory. In this study, we demonstrated that bone marrow mesenchymal stem cells (MSCs) harvested from goats with long-term estrogen deficiencies exhibited a lower proliferation rate and decreased osteogenic capacity, which are critical obstacles for bone defect repair in the elderly. However, by combining autologous enriched bone marrow mesenchymal stem cells with porous β-TCP, we successfully repaired critical-sized bone defects in the medial femoral condyle of the osteoporotic goats. Both micro-CT images and histomorphometry analysis illustrated improved bone formation following the enriched MSC therapy. Thus, we proposed autologous enriched bone marrow mesenchymal stem cells as a quick, safe therapeutic strategy to treat osteoporotic bone defects.

Link to Article

http://dx.doi.org/10.1016/j.biomaterials.2012.03.069

Assessment of changes to the dental follicle in deep and partially impacted mandibular third molar

Author

Kamal, Abeer; Allam, Eman; Dehis, Mohammed; Zunt, Susan; Windsor, L. Jack

Abstract

Residual dental follicles surrounding the crowns of impacted teeth may represent a significant risk for their potential pathological changes. In this study, the expression levels of cell cycle proteins, proliferating cell nuclear antigen (PCNA), cyclin D1, and p21 were evaluated using immunohistochemistry. Twenty-two impacted mandibular third molars in 17 healthy individuals were evaluated in this study. They were divided into two groups on the basis of the depth of impaction: the partially impacted group and the fully impacted group. The impacted teeth were surgically removed and the surrounding follicle was curetted and examined by immunohistochemistry to evaluate whether there was a difference in cell cycle regulation between the two groups. PCNA was expressed in most of the epithelial cells with no significant difference between the groups. The p21 expression was significantly higher in the full bony impaction group. Cyclin D1 expression was expressed at low levels with no significant difference between the groups. Weak cyclin D1 expression was consistent with high p21, a negative regulator of the cell cycle. The high p21 expression could be a compensatory mechanism to the high PCNA levels. These results suggest the possibility that dental follicles associated with full bony impactions possess different cellular activities compared with partial bony/soft-tissue impactions.

Link to Article

http://dx.doi.org/10.1097/01.OMX.0000412880.68174.21

IL-17 mediates estrogen-deficient osteoporosis in an Act1-dependent manner

Authors

Carl J. DeSelm, Yoshifumi Takahata, Julia Warren, Jean C. Chappel, Taimur Khan, Xiaoxia Li, Caini Liu, Yongwon Choi, Youngmi Faith Kim, Wei Zou, Steven L. Teitelbaum

Abstract

Estrogen-deficient osteoporosis may be an inflammatory disorder and we therefore asked if IL-17 participates in its pathogenesis. Deletion of the principal IL-17 receptor (IL-17RA) protects mice from ovariectomy (OVX)-induced bone loss. Further supporting a central role of IL-17 in its pathogenesis, OVX-induced osteoporosis is prevented by a blocking antibody targeting the cytokine. IL-17 promotes osteoclastogenesis by stimulating RANK ligand (RANKL) expression by osteoblastic cells, mediated by the IL-17RA SEFIR/TILL domain. Estrogen deprivation, however does not enhance IL-17RA mRNA expression by osteoblasts or in bone, but augments that of Act1, an IL17RA-interacting protein and signaling mediator. Similar to IL-17RA-/- mice, those lacking Act1 are protected from OVX-induced bone loss. Also mirroring IL-17RA-deficiency, absence of Act1 in osteoblasts, but not osteoclasts, impairs osteoclastogenesis via dampened RANKL expression. Transduction of WT Act1 into Act1-/- osteoblasts substantially rescues their osteoclastogenic capacity. The same construct, however, lacking its E3 ligase U-box or its SEFIR domain, which interacts with its counterpart in IL-17RA, fails to do so. Estrogen deprivation, therefore, promotes RANKL expression and bone resorption in association with upregualtion of the IL-17 effector, Act1, supporting the concept that post-menopausal osteoporosis is a disorder of innate immunity.

Link to Article

http://dx.doi.org/10.1002/jcb.24165

Age-Related Skeletal Dynamics and Decrease in Bone Strength in DNA Repair Deficient Male Trichothiodystrophy Mice

Authors

Claudia Nicolaije, Karin E. M. Diderich, S. M. Botter, Matthias Priemel, Jan H. Waarsing, Judd S. Day, Renata M. C. Brandt, Arndt F. Schilling, Harrie Weinans, Bram C. Van der Eerden, Gijsbertus T. J. van der Horst, Jan H. J. Hoeijmakers, Johannes P. T. M. van Leeuwen

Abstract

Accumulation of DNA damage caused by oxidative stress is thought to be one of the main contributors of human tissue aging. Trichothiodystrophy (TTD) mice have a mutation in the Ercc2 DNA repair gene, resulting in accumulation of DNA damage and several features of segmental accelerated aging. We used male TTD mice to study the impact of DNA repair on bone metabolism with age. Analysis of bone parameters, measured by micro-computed tomography, displayed an earlier decrease in trabecular and cortical bone as well as a loss of periosteal apposition and a reduction in bone strength in TTD mice with age compared to wild type mice. Ex vivo analysis of bone marrow differentiation potential showed an accelerated reduction in the number of osteogenic and osteoprogenitor cells with unaltered differentiation capacity. Adipocyte differentiation was normal. Early in life, osteoclast number tended to be increased while at 78 weeks it was significantly lower in TTD mice. Our findings reveal the importance of genome stability and proper DNA repair for skeletal homeostasis with age and support the idea that accumulation of damage interferes with normal skeletal maintenance, causing reduction in the number of osteoblast precursors that are required for normal bone remodeling leading to a loss of bone structure and strength.

Link to Article

http://dx.doi.org/10.1371/journal.pone.0035246

Comparison of isolation and expansion techniques for equine osteogenic progenitor cells from periosteal tissue

Authors

McDuffee, Laurie A.

Abstract

Stem cell therapy and cell-based therapies using other progenitor cells are becoming the treatment of choice for many equine orthopedic lesions. Important criteria for obtaining autogenous equine progenitor cells in vitro for use in clinical cell-based therapy include the ability to isolate and expand cells repeatedly to high numbers (millions) required for therapy, in a clinically relevant time frame. Cells must also maintain their ability to differentiate into the tissue type of choice. The objective of this study was to compare isolation and expansion techniques for preparation of periosteal-derived osteogenic progenitor cells for use in commercial autogenous cell-based therapy. Cells were allowed to migrate spontaneously from periosteal tissue or were enzymatically released. Isolated cells were expanded using enzymatic detachment of cells and subsequent monolayer or dynamic culture techniques. Viable osteogenic progenitor cells from each group were counted at 2 weeks, and osteogenic potential determined. Cells isolated or expanded using the explant or bioreactor technique yielded cells at a much lower number per gram of tissue compared with that of enzyme digestion and monolayer expansion, but all cells were able to differentiate into the ostoblast phenotype. Osteogenic progenitor cells isolated by enzymatic release and expanded using monolayer culture reached the highest number of viable cells per gram of donor periosteal tissue while maintaining the ability to differentiate into bone forming cells in vitro. This technique would be an easy, consistent method of preparation of equine osteogenic cells for clinical cell based therapy for orthopedic conditions.

Link to Article

http://www.ingentaconnect.com/content/cvma/cjvr/2012/00000076/00000002/art00002

Repression of osteocyte Wnt/β-catenin signaling is an early event in the progression of renal osteodystrophy

Authors

Yves Sabbagh, Fabiana Giorgeti Graciolli, Stephen O'Brien, Wen Tang, Luciene Machado dos Reis, Susan Ryan, Lucy Phillips, Joseph Boulanger, Wenping Song, Christina Bracken, Shiguang Liu, Steven Ledbetter, Paul Dechow, Maria Eugenia F Canziani, Aluizio B Carvalho, Vanda Jorgetti, Rosa MA Moyses, Susan C Schiavi

Abstract

Chronic kidney disease-mineral bone disorder (CKD-MBD) is defined by abnormalities in mineral and hormone metabolism, bone histomorphometric changes and/or the presence of soft tissue calcification. Emerging evidence suggests that features of CKD-MBD may occur early in disease progression and are associated with changes in osteocyte function. To identify early changes in bone, we utilized the jck mouse, a genetic model of polycystic kidney disease that exhibits progressive renal disease. At 6 weeks of age, jck mice have normal renal function and no evidence of bone disease but exhibit continual decline in renal function and death by 20 weeks of age, when approximately 40-60% of them have vascular calcification. Temporal changes in serum parameters were identified in jck relative to wild-type mice from 6 through 18 weeks of age and subsequently shown to largely mirror serum changes commonly associated with clinical CKD-MBD. Bone histomorphometry revealed progressive changes associated with increased osteoclast activity and elevated bone formation relative to wild-type mice. To capture the early molecular and cellular events in the progression of CKD-MBD we examined cell-specific pathways associated with bone remodeling at the protein and/or gene expression level. Importantly, a steady increase in the number of cells expressing phosphor-Ser33/37-β-catenin was observed both in mouse and human bones. Overall repression of Wnt/β-catenin signaling within osteocytes occurred in conjunction with increased expression of Wnt antagonists (SOST and sFRP4) and genes associated with osteoclast activity, including RANKL. The resulting increase in the RANKL/OPG ratio correlated with increased osteoclast activity. In late stage disease, an apparent repression of genes associated with osteoblast function was observed. These data confirm that jck mice develop progressive biochemical changes in CKD-MBD and suggest that repression of the Wnt/β-catenin pathway is involved in the pathogenesis of renal osteodystrophy.

Link to Article

http://dx.doi.org/10.1002/jbmr.1630