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COMP-angiopoietin1 potentiates the effects of bone morphogenic protein-2 on ischemic necrosis of the femoral head in rats.

Zhou L, Yoon SJ, Jang KY, Moon YJ, Wagle S, Lee KB, Park BH, Kim JR - PLoS ONE (2014)

Bottom Line: Radiographs obtained six weeks after injection revealed better preservation of the architecture of the femoral head in the COMP-Ang1 + BMP-2 group compared with the BSA and BMP-2 groups.Histological findings indicated increased trabecular bone and vascularity and decreased osteoclast bone resorption activity in the COMP-Ang1 + BMP-2 group compared with those in the BSA and BMP-2 groups.These results suggest that COMP-Ang1 preserved the necrotic femoral head through the potentiation of BMP-2 signaling pathways and angiogenesis.

View Article: PubMed Central - PubMed

Affiliation: Departments of Orthopedic Surgery, Chonbuk National University Medical School, Research Institute for Endocrine Sciences and Research Institute of Clinical Medicine, Jeonju, Republic of Korea; Department of Sports Medicine, Taishan Medical University, Shandong, China.

ABSTRACT
Angiogenesis is considered essential for proper bone regeneration. The purpose of this investigation was to determine if a combined therapy of bone morphogenetic protein-2 (BMP-2) and cartilage oligomeric matrix protein angiopoietin-1 (COMP-Ang1) can potentiate the therapeutic effect of BMP-2 in a rat model of ischemic necrosis of the femoral head (INFH). INFH was surgically induced in the femoral head of rats, and the animals were divided into the following groups: 1) a sham-operated group (sham group), 2) a bovine serum albumin-injected group (BSA group), 3) a BMP-2-injected group (BMP-2 group), and 4) a COMP-Ang1 and BMP-2-injected group (COMP-Ang1 + BMP-2 group) (n = 20/group). Radiologic, histologic, and histomorphometric assessments were performed to assess femoral head morphology, vascular density, and bone resorption activity. Western blots and immunohistochemical staining were performed to evaluate production of BMP-related signaling proteins in C3H10T1/2 cells and tissues. Real-time RT-PCR was performed to investigate expression of the target integrin gene, and the effect of integrin on C3H10T1/2 cells was determined using a cell adhesion assay. Radiographs obtained six weeks after injection revealed better preservation of the architecture of the femoral head in the COMP-Ang1 + BMP-2 group compared with the BSA and BMP-2 groups. Histological findings indicated increased trabecular bone and vascularity and decreased osteoclast bone resorption activity in the COMP-Ang1 + BMP-2 group compared with those in the BSA and BMP-2 groups. The combination of COMP-Ang1 and BMP-2 increased phosphorylation of Smad1/3/5, p38, and Akt. Increased integrin α3 and β1 mRNA expression in the COMP-Ang1 + BMP-2 group promoted cell adhesion. These results suggest that COMP-Ang1 preserved the necrotic femoral head through the potentiation of BMP-2 signaling pathways and angiogenesis. Combination treatment with COMP-Ang1 and BMP-2 may be a clinically useful therapeutic application in INFH.

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Immunohistochemical staining for factor VIII-related antigen and vascular densities in infarcted femoral heads.(A) Immunohistochemical staining for factor VIII-related antigen in the sham, BSA, BMP-2, and COMP-Ang1 + BMP-2 groups. (B) Vascular densities were measured in six rats from each group and two images were taken (magnification ×200) of each femoral head. The number of factor VIII-related antigen-positive vessels was significantly higher in the COMP-Ang1 + BMP-2 group than in the BSA and BMP-2 groups. Vascular density in each image was calculated as follows: vascular area stained by antibody for factor VIII-related antigen/total area of each image × 100 (%). Data are expressed as the mean ± SEM (n =  6 per group). *p<0.01 vs. sham; **p<0.01 vs. BSA or BMP.
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pone-0110593-g003: Immunohistochemical staining for factor VIII-related antigen and vascular densities in infarcted femoral heads.(A) Immunohistochemical staining for factor VIII-related antigen in the sham, BSA, BMP-2, and COMP-Ang1 + BMP-2 groups. (B) Vascular densities were measured in six rats from each group and two images were taken (magnification ×200) of each femoral head. The number of factor VIII-related antigen-positive vessels was significantly higher in the COMP-Ang1 + BMP-2 group than in the BSA and BMP-2 groups. Vascular density in each image was calculated as follows: vascular area stained by antibody for factor VIII-related antigen/total area of each image × 100 (%). Data are expressed as the mean ± SEM (n =  6 per group). *p<0.01 vs. sham; **p<0.01 vs. BSA or BMP.

Mentions: Angiogenesis is known to prevent femoral necrosis, and COMP-Ang1 is considered an angiogenic factor that functions through activation of the Tie2 receptor. Here, to confirm the effects of COMP-Ang1 on vascularity, femoral heads were retrieved, sectioned, and immunostained using antibody against factor VIII-related antigen (Figure 3A). Elevated vessel densities in the COMP-Ang1 + BMP-2 group specimens were confirmed by morphometric analysis of vessels in the secondary ossification center of infarcted femoral heads. As shown in Figure 3B, vascular densities in the BSA and BMP-2 groups were significantly lower than in the sham group (p <0.001); however, the vascular density of the COMP-Ang1 + BMP-2 group was significantly higher compared with that of the BMP-2 group (p <0.001). Vascular densities within the COMP-Ang1 + BMP-2 group were approximately four times higher than those of the BSA group and almost ten times higher than in the BMP-2 group. These differences among the BSA, BMP-2, and COMP-Ang1 + BMP-2 groups paralleled the radiological and histological findings.


COMP-angiopoietin1 potentiates the effects of bone morphogenic protein-2 on ischemic necrosis of the femoral head in rats.

Zhou L, Yoon SJ, Jang KY, Moon YJ, Wagle S, Lee KB, Park BH, Kim JR - PLoS ONE (2014)

Immunohistochemical staining for factor VIII-related antigen and vascular densities in infarcted femoral heads.(A) Immunohistochemical staining for factor VIII-related antigen in the sham, BSA, BMP-2, and COMP-Ang1 + BMP-2 groups. (B) Vascular densities were measured in six rats from each group and two images were taken (magnification ×200) of each femoral head. The number of factor VIII-related antigen-positive vessels was significantly higher in the COMP-Ang1 + BMP-2 group than in the BSA and BMP-2 groups. Vascular density in each image was calculated as follows: vascular area stained by antibody for factor VIII-related antigen/total area of each image × 100 (%). Data are expressed as the mean ± SEM (n =  6 per group). *p<0.01 vs. sham; **p<0.01 vs. BSA or BMP.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4201557&req=5

pone-0110593-g003: Immunohistochemical staining for factor VIII-related antigen and vascular densities in infarcted femoral heads.(A) Immunohistochemical staining for factor VIII-related antigen in the sham, BSA, BMP-2, and COMP-Ang1 + BMP-2 groups. (B) Vascular densities were measured in six rats from each group and two images were taken (magnification ×200) of each femoral head. The number of factor VIII-related antigen-positive vessels was significantly higher in the COMP-Ang1 + BMP-2 group than in the BSA and BMP-2 groups. Vascular density in each image was calculated as follows: vascular area stained by antibody for factor VIII-related antigen/total area of each image × 100 (%). Data are expressed as the mean ± SEM (n =  6 per group). *p<0.01 vs. sham; **p<0.01 vs. BSA or BMP.
Mentions: Angiogenesis is known to prevent femoral necrosis, and COMP-Ang1 is considered an angiogenic factor that functions through activation of the Tie2 receptor. Here, to confirm the effects of COMP-Ang1 on vascularity, femoral heads were retrieved, sectioned, and immunostained using antibody against factor VIII-related antigen (Figure 3A). Elevated vessel densities in the COMP-Ang1 + BMP-2 group specimens were confirmed by morphometric analysis of vessels in the secondary ossification center of infarcted femoral heads. As shown in Figure 3B, vascular densities in the BSA and BMP-2 groups were significantly lower than in the sham group (p <0.001); however, the vascular density of the COMP-Ang1 + BMP-2 group was significantly higher compared with that of the BMP-2 group (p <0.001). Vascular densities within the COMP-Ang1 + BMP-2 group were approximately four times higher than those of the BSA group and almost ten times higher than in the BMP-2 group. These differences among the BSA, BMP-2, and COMP-Ang1 + BMP-2 groups paralleled the radiological and histological findings.

Bottom Line: Radiographs obtained six weeks after injection revealed better preservation of the architecture of the femoral head in the COMP-Ang1 + BMP-2 group compared with the BSA and BMP-2 groups.Histological findings indicated increased trabecular bone and vascularity and decreased osteoclast bone resorption activity in the COMP-Ang1 + BMP-2 group compared with those in the BSA and BMP-2 groups.These results suggest that COMP-Ang1 preserved the necrotic femoral head through the potentiation of BMP-2 signaling pathways and angiogenesis.

View Article: PubMed Central - PubMed

Affiliation: Departments of Orthopedic Surgery, Chonbuk National University Medical School, Research Institute for Endocrine Sciences and Research Institute of Clinical Medicine, Jeonju, Republic of Korea; Department of Sports Medicine, Taishan Medical University, Shandong, China.

ABSTRACT
Angiogenesis is considered essential for proper bone regeneration. The purpose of this investigation was to determine if a combined therapy of bone morphogenetic protein-2 (BMP-2) and cartilage oligomeric matrix protein angiopoietin-1 (COMP-Ang1) can potentiate the therapeutic effect of BMP-2 in a rat model of ischemic necrosis of the femoral head (INFH). INFH was surgically induced in the femoral head of rats, and the animals were divided into the following groups: 1) a sham-operated group (sham group), 2) a bovine serum albumin-injected group (BSA group), 3) a BMP-2-injected group (BMP-2 group), and 4) a COMP-Ang1 and BMP-2-injected group (COMP-Ang1 + BMP-2 group) (n = 20/group). Radiologic, histologic, and histomorphometric assessments were performed to assess femoral head morphology, vascular density, and bone resorption activity. Western blots and immunohistochemical staining were performed to evaluate production of BMP-related signaling proteins in C3H10T1/2 cells and tissues. Real-time RT-PCR was performed to investigate expression of the target integrin gene, and the effect of integrin on C3H10T1/2 cells was determined using a cell adhesion assay. Radiographs obtained six weeks after injection revealed better preservation of the architecture of the femoral head in the COMP-Ang1 + BMP-2 group compared with the BSA and BMP-2 groups. Histological findings indicated increased trabecular bone and vascularity and decreased osteoclast bone resorption activity in the COMP-Ang1 + BMP-2 group compared with those in the BSA and BMP-2 groups. The combination of COMP-Ang1 and BMP-2 increased phosphorylation of Smad1/3/5, p38, and Akt. Increased integrin α3 and β1 mRNA expression in the COMP-Ang1 + BMP-2 group promoted cell adhesion. These results suggest that COMP-Ang1 preserved the necrotic femoral head through the potentiation of BMP-2 signaling pathways and angiogenesis. Combination treatment with COMP-Ang1 and BMP-2 may be a clinically useful therapeutic application in INFH.

Show MeSH
Related in: MedlinePlus