[Show abstract][Hide abstract] ABSTRACT: Bone formation during fracture repair inevitably initiates within or around extravascular deposits of a fibrin-rich matrix. In addition to a central role in hemostasis, fibrin is thought to enhance bone repair by supporting inflammatory and mesenchymal progenitor egress into the zone of injury. However, given that a failure of efficient fibrin clearance can impede normal wound repair, the precise contribution of fibrin to bone fracture repair, whether supportive or detrimental, is unknown. Here, we employed mice with genetically and pharmacologically imposed deficits in the fibrin precursor fibrinogen and fibrin-degrading plasminogen to explore the hypothesis that fibrin is vital to the initiation of fracture repair, but impaired fibrin clearance results in derangements in bone fracture repair. In contrast to our hypothesis, fibrin was entirely dispensable for long-bone fracture repair, as healing fractures in fibrinogen-deficient mice were indistinguishable from those in control animals. However, failure to clear fibrin from the fracture site in plasminogen-deficient mice severely impaired fracture vascularization, precluded bone union, and resulted in robust heterotopic ossification. Pharmacological fibrinogen depletion in plasminogen-deficient animals restored a normal pattern of fracture repair and substantially limited heterotopic ossification. Fibrin is therefore not essential for fracture repair, but inefficient fibrinolysis decreases endochondral angiogenesis and ossification, thereby inhibiting fracture repair.
The Journal of clinical investigation 07/2015; 125(9). DOI:10.1172/JCI80313 · 13.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
The prevalence and cost of unnecessary advanced imaging studies (AIS) in the evaluation of long bone cartilaginous lesions have not been studied previously.
A total of 105 enchondromas and 19 chondrosarcomas arising in long bones from July 2008 until April 2012 in 121 patients were reviewed. Advanced imaging was defined as MRI, CT, bone scan, skeletal survey, or CT biopsy. Two blinded radiologists independently reviewed the initial imaging study and determined if further imaging was indicated based on that imaging study alone. The cost of imaging was taken from our institution's global charge list. Imaging was deemed unnecessary if it was not recommended by our radiologists after review of the initial imaging study. The difference in cost was calculated by subtracting the cost of imaging recommended by each radiologist from the cost of unnecessary imaging. The sensitivity and specificity for distinguishing enchondromas from chondrosarcomas was calculated. A minimum of 2 years from diagnosis of an enchondroma was required to monitor for malignant transformation.
Of patients diagnosed with an enchondroma, 85 % presented with AIS. The average enchondroma patient presented with one unnecessary AIS. The radiologists' interpretations agreed 85 % of the time for enchondromas and 100 % for chondrosarcomas. The sensitivity and specificity for distinguishing enchondromas from chondrosarcomas was 95 % for one radiologist and 87 and 95 % for the other. The average unnecessary cost per enchondroma patient was $1,346.18.
Unnecessary AIS are frequently performed and are a significant source of expense. The imaging algorithms outlined in this study may reduce unnecessary AIS.
[Show abstract][Hide abstract] ABSTRACT: Underlying vascular disease is an important pathophysiologic factor shared among many co-morbid conditions associated with poor fracture healing, such as diabetes, obesity, and age. Determining the temporal and spatial patterns of revascularization following fracture is essential for devising therapeutic strategies to augment this critical reparative process. Seminal studies conducted in the last century have investigated the pattern of vascularity in bone following fracture. The consensus model culminating from these classical studies depicts a combination of angiogenesis emanating from both the intact intramedullary and periosteal vasculature. Subsequent to the plethora of experimental fracture angiography in the early to mid-20th century there has been a paucity of reports describing the pattern of revascularization of a healing fracture. Consequently the classical model of revascularization of a displaced fracture has remained largely unchanged. Here, we have overcome the limitations of animal fracture models performed in the above described classical studies by combining novel techniques of bone angiography and a reproducible murine femur fracture model to demonstrate for the first time the complete temporal and spatial pattern of revascularization in a displaced/stabilized fracture. These studies were designed specifically to i) validate the classical model of fracture revascularization of a displaced/stabilized fracture ii) assess the association between intramedullary and periosteal angiogenesis and iii) elucidate the expression of VEGF/VEGF-R in relation to the classical model. From the studies, in conjunction with classic studies of angiogenesis during fracture repair, we propose a novel model (see abstract graphic) that defines the process of bone revascularization subsequent to injury to guide future approaches to enhance fracture healing. This new model validates and advances the classical model by providing evidence that during the process of revascularization of a displaced fracture 1) periosteal angiogenesis occurs in direct communication with the remaining intact intramedullary vasculature as a result of a vascular shunt and 2) vascular union occurs through an intricate interplay between intramembranous and endochondral VEGF/VEGF-R mediated angiogenesis.
Bone 10/2014; 67. DOI:10.1016/j.bone.2014.07.002 · 3.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Obesity is a growing epidemic and has been associated with an increased frequency of complications after various surgical procedures. Studies also have shown adipose tissue to promote a microenvironment favorable for tumor growth. Additionally, the relationship between obesity and prognosis of soft tissue sarcomas has yet to be evaluated.
Clinical Orthopaedics and Related Research 06/2014; 472(9). DOI:10.1007/s11999-014-3714-7 · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Radiographic imaging plays a crucial role in the diagnosis of osteosarcoma. Currently, computed-tomography (CT) is used to measure tumor-induced osteolysis as a marker for tumor growth by monitoring the bone fractional volume. As most tumors primarily induce osteolysis, lower bone fractional volume has been found to correlate with tumor aggressiveness. However, osteosarcoma is an exception as it induces osteolysis and produces mineralized osteoid simultaneously. Given that competent bone is highly anisotropic (systematic variance in its architectural order renders its physical properties dependent on direction of load) and that tumor induced osteolysis and osteogenesis are structurally disorganized relative to competent bone, we hypothesized that μCT-derived measures of anisotropy could be used to qualitatively and quantitatively detect osteosarcoma provoked deviations in bone, both osteolysis and osteogenesis, in vivo. We tested this hypothesis in a murine model of osteosarcoma cells orthotopically injected into the tibia. We demonstrate that, in addition to bone fractional volume, μCT-derived measure of anisotropy is a complete and accurate method to monitor osteosarcoma-induced osteolysis. Additionally, we found that unlike bone fractional volume, anisotropy could also detect tumor-induced osteogenesis. These findings suggest that monitoring tumor-induced changes in the structural property isotropy of the invaded bone may represent a novel means of diagnosing primary and metastatic bone tumors.
PLoS ONE 06/2014; 9(6):e97381. DOI:10.1371/journal.pone.0097381 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: IntroductionThe standard of care for extremity soft tissue sarcomas continues to be negative-margin limb salvage surgery. Radiotherapy is frequently used as an adjunct to decrease local recurrence. No differences in survival have been found between preoperative and postoperative radiotherapy regimens. However, it is uncertain if the use of a postoperative boost in addition to preoperative radiotherapy reduces local recurrence rates.Methods
This retrospective review evaluated patients who received preoperative radiotherapy (n = 49) and patients who received preoperative radiotherapy with a postoperative boost (n = 45). The primary endpoint analysed was local recurrence, with distant metastasis and death due to sarcoma analysed as secondary endpoints. Wilcoxon rank-sum test and either χ2 or Fisher's exact test were used to compare variables. Multivariable regression analyses were used to take into account potential confounders and identify variables that affected outcomes.ResultsNo differences in the proportion or rate of local recurrence, distant metastasis or death due to sarcoma were observed between the two groups (P > 0.05). The two groups were similarly matched with respect to demographics such as age, race and sex and tumour characteristics including excision status, tumour site, size, depth, grade, American Joint Committee on Cancer stage, chemotherapy receipt and histological subtype (P > 0.05). The postoperative boost group had a larger proportion of patients with positive microscopic margins (62% vs 10%; P < 0.001).Conclusion
No differences in rates of local recurrence, distant metastasis or death due to sarcoma were found in patients who received both pre- and postoperative radiotherapy when compared with those who received only preoperative radiotherapy.
Journal of Medical Imaging and Radiation Oncology 06/2014; 58(5). DOI:10.1111/1754-9485.12184 · 1.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Unlabelled:
Osteosarcoma is the most common primary bone malignancy and accounts for more than half of primary skeletal malignancies in children and young adults. Although vascular endothelial growth factor (VEGF) expression in osteosarcoma has been associated with poor outcome, its role in the pathogenesis of osteosarcoma remains controversial. Here, VEGF and VEGFR1 expression in both human and murine osteosarcoma cells associated with increasing malignant potential. Autocrine VEGF/VEGFR1 signaling resulted in constitutive activation of VEGFR1 in highly aggressive osteosarcoma cells. In addition, survival and proliferation of highly aggressive osteosarcoma cells was dependent on autocrine VEGF/R1 signaling in vitro. The effect of VEGFR1 expression on in vivo tumor growth and angiogenesis was evaluated by immunoselecting subpopulations of osteosarcoma cells that express high or low levels of VEGFR1. Cell enriched for high VEGFR1 expression showed increased VEGF production, tumor growth, tumor angiogenesis, and osteolysis in vivo. In addition, it was demonstrated that VEGF and VEGFR1 are coexpressed by a subset of tumor cells in human osteosarcoma, similar to what was observed in the murine osteosarcoma cells. These results suggest that autocrine VEGF/VEGFR1 signaling in a subpopulation of tumor cells plays a pivotal role in osteosarcoma progression.
Aggressive osteosarcoma phenotypes are mediated by autocrine VEGF/VEGFR1 signaling and improved stratification measures and novel anti-angiogenic strategies may benefit this specific tumor type.
Molecular Cancer Research 04/2014; 12(8). DOI:10.1158/1541-7786.MCR-14-0037 · 4.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Osteosarcoma is the most common primary malignant tumor of bone and accounts for half of all primary skeletal malignancies in children and teenagers. The prognosis for patients who fail or progress on first-line chemotherapy protocols is poor, therefore, additional adjuvant therapeutic strategies are needed. A recent feasibility study has demonstrated that the nitrogen-containing bisphosphonate zoledronic acid (ZOL) can be combined safely with conventional chemotherapy. However, the pharmacodynamics of bisphosphonate therapy is not well characterized. Osteosarcoma is a highly angiogenic tumor. Recent reports of the anti-angiogenic effects of bisphosphonates prompted us to determine whether nitrogen-containing bisphosphonates (ZOL and alendronate) treatment attenuate osteosarcoma growth by inhibition of osteoclast activity, tumor-mediated angiogenesis, or direct inhibitory effects on osteosarcoma. Here, we demonstrate that bisphosphonates directly inhibit VEGFR2 expression in endothelial cells, as well as endothelial cell proliferation and migration. Additionally, bisphosphonates also decrease VEGF-A expression in osteosarcoma (K7M3) cells, resulting in reduced stimulation of endothelial cell migration in co-culture assays. ZOL also decreases VEGFR1 expression in aggressive osteosarcoma cell lines (K7M3, 143B) and induces apoptosis of these cells, but has negligible effects on less aggressive osteosarcoma cell lines (K12 and TE85). In vivo ZOL treatment results in significant reduction in osteosarcoma-initiated angiogenesis and tumor growth in a murine model of osteosarcoma. In conclusion, bisphosphonates have diverse growth inhibitory effects on osteosarcoma through: (1) activation of apoptosis and inhibition of cell proliferation, (2) inhibition of VEGF-A and VEGFR1 expression by tumor cells, (3) inhibition of tumor-induced angiogenesis, and (4) direct inhibitory actions on endothelial cells.
Bone 03/2014; 63. DOI:10.1016/j.bone.2014.03.005 · 3.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Racial disparities in access and survival have been reported in a variety of cancers. These issues, however, have yet to be explored in detail in patients with soft-tissue sarcomas (STS). The purpose of this paper was to investigate the independent role of race with respect to survival outcomes in STS.
A total of 7601 patients were evaluated in this study. A SEER registry query for patients over 20 years old with extremity STS diagnosed between 2004 and 2009 (n=7225) was performed. Survival outcomes were analyzed after patients were stratified by race. Multivariable survival models were used to identify independent predictors of sarcoma-specific death. The Wilcoxon rank-sum test was used to compare continuous variables. Statistical significance was maintained at P<0.05.
This study showed that African American patients were more likely to die of their STS. They were younger at presentation (P=0.001), had larger tumors (P<0.001), had less surgery (P=0.002), received radiotherapy less frequently (P=0.024), had higher family income (P<0.001), and were less likely to be married (P<0.001). African American race by itself was not an independent predictor of death.
African Americans encounter death due to STS at a much larger proportion and faster rate than their respective white counterparts. African Americans frequently present with a larger size tumor, do not undergo surgical resection, or receive radiation therapy as frequently as compared with their white peers. Barriers to timely and appropriate care should be further investigated in this group of at-risk patients.
American journal of clinical oncology 01/2014; 38(6). DOI:10.1097/COC.0000000000000004 · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background and objectives:
Administration of preoperative radiotherapy for extremity soft tissue sarcoma improves local control, while allowing for a more conservative surgical resection. During radiation treatment tumor size typically decreases or remains constant. In a subset of patients, however, a size increase in the tumor occurs. Our goal was to investigate the prognosis of patients who had a size increase of at least 20% over the course of preoperative radiotherapy versus those who did not.
This retrospective study evaluated 70 patients treated for localized primary STS of the extremities between January 2000 and December 2008. Kaplan-Meier curves for disease-specific and metastasis-free survival were calculated for both groups.
Sixty-one patients had stable or decrease local tumor size following preoperative radiotherapy and nine patients had an increase of at least 20% in tumor size. There were no statistically significant differences found in disease-specific survival and metastasis-free survival (Gray's test, P = 0.93 and P = 0.68, respectively) among the two groups.
Our results indicate that a 20% increase in tumor size following preoperative radiotherapy did not result in a worse outcome for patients when compared to those who had stable or decrease local tumor size following preoperative radiotherapy.
[Show abstract][Hide abstract] ABSTRACT: Background:
Although survival outcomes have been evaluated between those undergoing a planned primary excision and those undergoing a reexcision following an unplanned resection, the financial implications associated with a reexcision have yet to be elucidated.
A query for financial data (professional, technical, indirect charges) for soft tissue sarcoma excisions from 2005 to 2008 was performed. A total of 304 patients (200 primary excisions and 104 reexcisions) were identified. Wilcoxon rank sum tests and χ2 or Fisher's exact tests were used to compare differences in demographics and tumor characteristics. Multivariable linear regression analyses were performed with bootstrapping techniques.
The average professional charge for a primary excision was $9,694 and $12,896 for a reexcision (p<.001). After adjusting for tumor size, American Society of Anesthesiologists status, grade, and site, patients undergoing reexcision saw an increase of $3,699 in professional charges more than those with a primary excision (p<.001). Although every 1-cm increase in size of the tumor results in an increase of $148 for a primary excision (p=.006), size was not an independent factor in affecting reexcision charges. The grade of the tumor was positively associated with professional charges of both groups such that higher-grade tumors resulted in higher charges compared to lower-grade tumors (p<.05).
Reexcision of an incompletely excised sarcoma results in significantly higher professional charges when compared to a single, planned complete excision. Additionally, when the cost of the primary unplanned surgery is considered, the financial burden nearly doubles.
[Show abstract][Hide abstract] ABSTRACT: Despite reports of sex steroid receptor and COX2 expression in desmoid-type fibromatosis, responses to single agent therapy with anti-estrogens and nonsteroidal anti-inflammatory drugs are unpredictable. Perhaps combination pharmacotherapy might be more effective in desmoid tumors that co-express these targets. Clearly, a further understanding of the signaling pathways deregulated in desmoid tumors is essential for development of targeted molecular therapy. Transforming growth factor-β (TGFβ) and bone morphogenetic proteins (BMPs) are important regulators of fibroblast proliferation and matrix deposition, but little is known about the TGFβ superfamily in fibromatosis. A tissue microarray representing 27 desmoid tumors was constructed; 14 samples of healing scar and 6 samples of normal fibrous tissue were included for comparison. Expression of selected receptors and activated downstream transcription factors of TGFβ family signaling pathways, β-catenin, sex steroid hormone receptors and COX2 were assessed by immunohistochemistry; patterns of co-expression were explored via correlational statistical analyses. In addition to β-catenin, immunoreactivity for phosphorylated SMAD2/3 (indicative of active TGFβ signaling) and COX2 was significantly increased in desmoid tumors compared to healing scar and quiescent fibrous tissue. Low levels of phosphorylated SMAD1/5/8 were detected in only a minority of cases. TGFβ receptor type 1 and androgen receptor were expressed in both desmoid tumors and scar, but not in fibrous tissue. Estrogen receptor-β was present in all cases studied. TGFβ signaling appears to be activated in desmoid-type fibromatosis and phosphorylated SMAD2/3 and COX2 immunoreactivity may be of diagnostic utility in these tumors. Given the frequency of androgen receptor, estrogen receptor-β and COX2 co-expression in desmoid tumors, further assessment of the efficacy of combination pharmacotherapy using hormonal agonists/antagonists together with COX2 inhibitors should be considered.
Cancer Science 10/2012; 103(12). DOI:10.1111/cas.12037 · 3.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To determine if amputation increases survival when compared to limb salvage surgery in patients with a soft tissue sarcoma (STS) of the extremity when there is often a misconception among physicians and patients that ablative surgery eliminates local recurrence and increases overall survival. This retrospective cohort study assessed 278 patients with STS and compared 18 patients who had undergone amputations for soft tissue sarcomas of the extremities to a comparative cohort of 260 patients who underwent limb salvage surgery during the same time period. Our limb salvage surgery (LSS) rate was 94% overall for soft tissue sarcomas with a median follow-up of 3.1 years. Patients undergoing amputations either had tumors that involved a critical neurovascular bundle (in particular nerve rather than vessel resection was more responsible for a decision toward ablation), or underlying bone or had neoplasms whose large size would require such an enormous resection that a functional limb would not remain. In comparing prognostic effects, mainly death due to sarcoma, distant metastasis and local recurrence, it was found that there was no statistically significant difference between patients undergoing amputation to those undergoing limb salvage surgery (p > 0.05). While amputations do not increase overall survival in soft tissue sarcomas of the extremity as compared to LSS, they are still a valuable option in a surgeon's arsenal. In particular, amputations can provide improved local control and symptomatic treatment in patients who might not be candidates for limb salvage surgery.
European journal of surgical oncology: the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology 09/2012; 38(12). DOI:10.1016/j.ejso.2012.08.024 · 3.01 Impact Factor