The miR-3074/BMP7 axis regulates TGF-ß-caused activation of hepatic stellate cells in vitro and CCl4-caused murine liver fibrosis in vivo.

Continuously progressive hepatic fibrosis might cause chronic liver diseases, resulting in hepatic failure. The activation of hepatic stellate cells (HSCs) residing in the liver might induce and influence hepatic fibrosis. In the present study, microRNA 3074 (miR-3074) was found increased within transforming growth factor-ß (TGF-ß)-activated HSCs and enriched within the TGF-ß signaling. In activated HSCs by TGF-ß, miR-3074 overexpression aggravated TGF-ß-induced fibrotic changes, whereas miR-3074 inhibition exerted opposite effects. miR-3074 directly targeted bone morphogenetic protein 7 (BMP7) and inhibited BMP7 expression. Under TGF-ß induction, overexpressed BMP7 notably attenuated the promotive roles of miR-3074 overexpression in TGF-ß-activated HSCs. Within carbon tetrachloride (CCl4)-caused liver fibrosis murine model, miR-3074 agomir administration promoted, while LV-BMP7 administration alleviated CCl4-induced fibrotic changes; LV-BMP7 significantly attenuated the effects of miR-3074 agomir. Lastly, mmu-miR-3074 also targeted mouse BMP7 and inhibited mouse BMP7 expression. In conclusion, the miR-3074/BMP7 axis regulates TGF-ß-caused activation of HSCs in vitro and CCl4-caused murine liver fibrosis in vivo. BMP7-mediated Smad1/5/8 activation might be involved.

Bone Morphogenetic Proteins in Anterior Cervical Fusion: A Systematic Review and Meta-Analysis.

OBJECTIVE: Bone morphogenetic proteins (BMPs) have been commonly used as a graft substitute in spinal fusion. Although the U.S. Food and Drug Administration issued a warning on life-threatening complications of recombinant human BMPs (rhBMPs) in cervical spine fusion in 2008, their off-label use has been continued. This investigation aimed to review the evidence for the use of rhBMP-2 and rhBMP-7 in anterior cervical spine fusions. METHODS: A comprehensive search was performed through Ovid (MEDLINE), PubMed, and Embase. The risk of bias assessment was according to the recommended criteria by the Cochrane Back and Neck group and MINORS (Methodological Index for Non-Randomized Studies). A wide array of radiographic and clinical outcomes including the adverse events were collated. RESULTS: Eighteen articles (1 randomized and 17 nonrandomized) were eligible for inclusion. The fusion rate was higher with use of rhBMP in most studies and our meta-analysis of the pooled data from 4782 patients confirmed this finding (odds ratio, 5.45; P < 0.00001). Altogether, the rhBMP and control groups were comparable in patient-reported outcomes. However, most studies tended to show a significantly higher incidence of overall complication rate, dysphagia/dysphonia, cervical swelling, readmission, wound complications, neurologic complications, and ossification. CONCLUSIONS: Application of rhBMPs in cervical spine fusion yields a significantly higher fusion rate with similar patient-reported outcomes, yet increased risk of life-threatening complications. Thus, we do not recommend the use of rhBMP in anterior cervical fusions.

Bone morphogenetic protein-binding peptide reduces the inflammatory response to recombinant human bone morphogenetic protein-2 and recombinant human bone morphogenetic protein-7 in a rodent model of soft-tissue inflammation.

BACKGROUND CONTEXT: Bone morphogenetic protein (BMP)-2 and BMP-7 are used to enhance bone formation in spine surgery, but the use of these materials is associated with side effects including inflammation, especially in the soft tissues of the neck. Bone morphogenetic protein-binding peptide (BBP) binds BMP-2 and BMP-7 and imparts a "slow-release" property to collagen carrier. PURPOSE: To test the hypothesis that the addition of BBP will reduce the soft-tissue inflammation induced by the implantation of BMP-2 and BMP-7 on a collagen sponge. STUDY DESIGN/SETTING: Prospective in vivo rodent model of inflammation. METHODS: We implanted six different materials absorbed onto collagen sponges: absorbable collagen sponge (ACS) alone; BBP alone; recombinant human bone morphogenetic protein (rhBMP)-2 alone; rhBMP-2 plus BBP; rhBMP-7 alone; and rhBMP-7 plus BBP. Sponges were implanted bilaterally (subcutaneously [SC] and intramuscularly [IM]) into the backs of rats. Using magnetic resonance imaging, inflammation was assessed in terms of soft-tissue edema volume at 3 hours and at 2, 4, and 7 days. The animal subjects were killed on Day 7, and the dimensions of the inflammatory mass were measured manually in the case of SC tissue and those of the inflammatory zone were determined subsequently by microscopic examination in the case of muscle. RESULTS: Both the SC and the IM soft-tissue edema volumes in the rhBMP-2 plus BBP and the rhBMP-7 plus BBP groups were significantly lower than those observed in the rhBMP-2 alone and rhBMP-7 alone groups. The edema volume associated with BBP alone was greater than that associated with ACS alone but less than that associated with the other treatment groups. The measurements of inflammatory masses and zone yielded similar results. CONCLUSIONS: Bone morphogenetic protein-binding peptide may reduce the inflammatory response associated with the use of rhBMP-2 and rhBMP-7 in a rodent model of inflammation and in a form that has previously been shown to enhance the activity of BMPs. These preliminary studies suggest that BBP may have the potential to be used in the future to improve healing and reduce soft-tissue swelling in surgical applications of BMPs.

Nonunion of a sacral fracture refractory to bone grafting: internal fixation and osteogenic protein-1 (BMP-7) application.

Nonunion of a sacral fracture is a serious clinical condition: chronic pain, sitting discomfort, limp, neurological implications, and inability to work are frequent findings. Surgical treatment of these injuries often turns out to be technically difficult also for the expert pelvic surgeon and not infrequently provides poor radiographic and clinical results. The gold standard treatment at present is open excision, reaming of the nonunion site and internal fixation, performed by a multi-stage approach; as an adjunct, autologous cancellous bone grafting is usually performed in most severe cases. We report a case of a sacral nonunion in which traditional techniques failed, successfully treated by osteogenic protein-1 (BMP-7) application. The employment of BMPs demonstrated successful results in various types of fracture, but there is limited experience about their use in pelvic ring injuries: Further studies are necessary to better know the possible complications and to define their actual potential.

Phase 1 safety and tolerability study of BMP-7 in symptomatic knee osteoarthritis.

BACKGROUND: There are no proven therapies that modify the structural changes associated with osteoarthritis (OA). Preclinical data suggests that intra-articular recombinant human BMP-7 (bone morphogenetic protein-7) has reparative effects on cartilage, as well as on symptoms of joint pain. The objective of this study was to determine the safety and tolerability as well as dose-limiting toxicity and maximal tolerated dose of intra-articular BMP-7. The secondary objectives were to determine the effect on symptomatic responses through 24 weeks. METHODS: This was a Phase 1, double-blind, randomized, multi-center, placebo-controlled, single-dose escalation safety study consisting of 4 dosing cohorts in participants with knee OA. Each cohort was to consist of 8 treated participants, with treatment allocation in a 3:1 active (intra-articular BMP-7) to placebo ratio. Eligible participants were persons with symptomatic radiographic knee OA over the age of 40. The primary objective of this study was to determine the safety and tolerability of BMP-7 including laboratory assessments, immunogenicity data and radiographic assessments. Secondary objectives were to determine the proportion of participants with a 20%, 50%, and 70% improvement in the WOMAC pain and function subscales at 4, 8, 12, and 24 weeks. Other secondary outcomes included the change from baseline to 4, 8, 12, and 24 weeks for the OARSI responder criteria. RESULTS: The mean age of participants was 60 years and 73% were female. All 33 participants who were enrolled completed the study and most adverse events were mild or moderate and were similar in placebo and BMP-7 groups. The 1 mg BMP-7 group showed a higher frequency of injection site pain and there was no ectopic bone formation seen on plain x-rays. By week 12, most participants in both the BMP-7 and placebo groups experienced a 20% improvement in pain and overall the BMP-7 group was similar to placebo with regard to this measurement. In the participants who received 0.1 mg and 0.3 mg BMP-7, there was a trend toward greater symptomatic improvement than placebo. The other secondary endpoints showed similar trends including the OARSI responder criteria for which the BMP-7 groups had more responders than placebo. CONCLUSIONS: There was no dose limiting toxicity identified in this study. The suggestion of a symptom response, together with the lack of dose limiting toxicity provide further support for the continued development of this product for the treatment of osteoarthritis.

A prospective, randomized, controlled, multicenter study of osteogenic protein-1 in instrumented posterolateral fusions: report on safety and feasibility.

STUDY DESIGN: A prospective, randomized, controlled, multicenter clinical study. OBJECTIVE: To evaluate the safety and feasibility of osteogenic protein (OP)-1 in 1-level lumbar spine instrumented posterolateral fusions. SUMMARY OF BACKGROUND DATA: Instrumented posterolateral fusion with the use of autograft is a commonly performed procedure for a variety of spinal disorders. However, harvesting of bone from the iliac crest is associated with complications. A promising alternative for autograft are bone morphogenetic proteins. METHODS: As part of a larger prospective, randomized, multicenter study, 36 patients were included, who received a 1-level instrumented posterolateral fusion of the lumbar spine. All patients had a degenerative or isthmic spondylolisthesis with symptoms of neurologic compression. There were 2 treatment arms: OP-1 combined with locally available bone from laminectomy (OP-1 group) or iliac crest autograft (autograft group). The primary outcome was the fusion rate based on a computed tomography scan after 1-year follow-up. The clinical outcome was measured using the Oswestry Disability Index. Additionally, the safety of OP-1 was evaluated by comparing the number and severity of adverse events that occurred between both groups. RESULTS: Using strict criteria, fusion rates of 63% were found in the OP-1 group and 67% in the control group (P = 0.95). There was a decrease in Oswestry scores at subsequent postoperative time points compared with preoperative values (P > 0.001). There were no significant differences in the mean Oswestry scores between the study group and control group at any time point (P = 0.56). No product-related adverse events occurred. CONCLUSION: The results demonstrate that OP-1 combined with locally obtained autograft is a safe and effective alternative for iliac crest autograft in instrumented single-level posterolateral fusions of the lumbar spine. The main advantage of OP-1 is that it avoids morbidity associated with the harvesting of autogenous bone grafts from the iliac crest.

Ectopic bone formation in the pelvis after combined anterior and posterior fusion of the spine with osteogenic protein-1 use: a case report.

STUDY DESIGN: Case report. OBJECTIVE: We report the first described case of ectopic bone formation with osteogenic protein-1 (OP-1) use occurring in the pelvis after combined anterior and posterior spinal fusion. SUMMARY OF BACKGROUND DATA: OP-1 is a member of the transforming growth factor-beta superfamily of extracellular proteins involved in bone growth and formation. Potential side effects of OP-1 are not yet fully understood, and clinical data have failed to show significant adverse effects of OP-1. METHODS: The patient had flat-back syndrome with symptomatic junctional degenerative disease below the level of fusion and underwent staged anterior and posterior reconstruction. OP-1 was used in conjunction with local bone graft and crushed cancellous allograft in both anterior and posterior procedures. RESULTS: Bone grew adjacent to the left superior pubic rami, extending through the left rectus sheath and into the left psoas muscle. Subsequently, complete excision of the ectopic bone was performed. No local recurrence was noted at postoperative visits up to 5 months after excision. At that time, the patient had returned to work and was pleased with the level of function. CONCLUSIONS: Caution is justified with the use of OP-1. Clinical studies must be conducted to ensure appropriate dosing to prevent ectopic bone formation and deleterious effects.

Long-term effects of bone morphogenetic protein- based treatments in humans.

Bone morphogenetic proteins (BMPs) are low-molecular-weight proteins of the transforming growth factor-beta (TGF-ß) superfamily. In recent years, these growth and differentiation factors have been extensively researched for their multifunctional properties ranging from embryonic development to postnatal homeostasis. The defining ability of BMPs is the role they play in skeletal development and maintenance, especially the powerful osteoinductive activity for which these proteins are currently sought after. There are over 20 BMPs that have been discovered, with BMP-2 and BMP-7 currently being the only proteins of the group that are approved by the US Food and Drug Administration for clinical use as an autograft substitute for lumbar spinal interbody fusion procedures and for open tibial fractures with intramedullary nail fixation. BMP-2 has also been approved for use in dental bone grafting indications. However, a significant amount of off-label usage of these proteins has been reported, which has led to an industry approaching a billion dollars annually. In this review, we examine the long-term effects of BMPs as evidenced from in vitro, preclinical, and clinical studies.

Enhancement of difficult nonunion in children with osteogenic protein-1 (OP-1): early experience.

UNLABELLED: Numerous studies have described the use of osteogenic protein-1 (OP-1) in adults, but there are few reports in children. The objectives of this short-term followup cohort study were (1) to examine clinical and radiographic healing of persistent nonunions after OP-1 application in children; and (2) to determine the safety of OP-1 use in this sample. Clinical healing was defined by absence of pain and tenderness at the nonunion site and the ability to fully weight bear on the affected limb. Radiographic healing was determined by bony bridging of the nonunion site in at least one view. Safety was defined as the absence of major adverse events, including allergic reactions, infections, local inflammatory reactions, and heterotopic ossification. OP-1 was used in 19 patients who had an operative procedure for the bridging of persistent nonunions between 1999 and 2007. The mean age was 11.6 years (range, 4.8-20.3 years). Thirteen patients had persistent nonunion after one or more previous surgeries, prior to the initial OP-1 application. A single dose of 3.5 mg of OP-1 mixed with 1 g of Type I bovine collagen was applied to 23 sites of 19 patients. Three patients received additional OP-1 applications. Healing occurred clinically and radiographically in 17 of the 23 sites. Complications included four superficial pin site infections, one deep infection, and two fractures. No major local adverse event related to OP-1 application was noted in our sample. Our findings suggest OP-1 stimulates healing of persistent nonunions without major adverse events in our patient population. LEVEL OF EVIDENCE: Level IV, case series. See the guidelines online for a complete description of levels of evidence.

The synergistic effect of autograft and BMP-7 in the treatment of atrophic nonunions.

UNLABELLED: Combining autologous bone graft and recombinant human bone morphogenetic protein-7 (BMP-7) to treat long-bone fracture aseptic atrophic nonunions theoretically could promote bone healing at higher rates than each of these grafting agents separately. We retrospectively reviewed prospectively collected data on patient general characteristics, clinical outcomes, and complications over 3 years to determine the healing rates and the incidence of complications and adverse events of this "graft expansion rationale." There were 45 patients (32 male) with a median age of 43 years (range, 19-76 years). Minimum followup was 12 months (mean, 24.5 months; range, 12-65 months). There were seven humeral, 19 femoral, and 19 tibial nonunions. The median number of prior operations was two (range, 1-7). All fractures united. Clinical and radiographic union occurred within a median of 5 months (range, 3-14 months) and 6 months (range, 4-16 months), respectively. Thirty-nine (87%) patients returned to their preinjury occupation at a mean of 4.2 months (range, 3-6 months). The median visual analog scale pain score was 0.9 (range, 0-2.8; maximum 10), and the median functional score was 86 (range, 67-95; maximum 100) at the final followup. BMP-7 as a bone-stimulating agent combined with conventional autograft resulted in a nonunion healing rate of 100% in these 45 patients. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Heterotopic ossification after the use of commercially available recombinant human bone morphogenetic proteins in four patients.

Heterotopic ossification occurring after the use of commercially available bone morphogenetic proteins has not been widely reported. We describe four cases of heterotopic ossification in patients treated with either recombinant bone morphogenetic protein 2 or recombinant bone morphogenetic protein 7. We found that while some patients were asymptomatic, heterotopic ossification which had occurred around a joint often required operative excision with good results.

Weekly intra-articular injections of bone morphogenetic protein-7 inhibits osteoarthritis progression.

INTRODUCTION: We investigated the ability of a weekly intra-articular injection of bone morphogenetic protein (BMP)-7 to prevent osteoarthritis in rabbits with anterior cruciate ligament transections. METHODS: First, 36 knee joints were randomly divided into four groups: 50, 500, 5,000 ng BMP-7, and control. Knee cartilage was evaluated at 4, 8, and 12 weeks. Then, in order to control for individual differences, 500 ng BMP-7 was injected into one knee and phosphate-buffered saline (PBS) into the other, and the two knees were compared at 4, 8, and 12 weeks (n = 5). For pharmacokinetic analysis, cartilage was harvested at 1 hour and 1, 2, 4, and 7 days after knee injection of 500 ng BMP-7 or PBS (n = 3). RESULTS: Histological scores in the 500 and 5,000 ng BMP-7 groups were significantly better than those in the other groups at 12 weeks. Matched pair analysis demonstrated that both macroscopic and histological scores in the 500 ng BMP-7 group were better than those in the control group. Immunohistochemical analysis revealed higher BMP-7 expression by chondrocytes in the BMP-7 injected knees. Histology of whole knee and quantitative micro computed tomography analysis showed that weekly injections of 500 ng BMP-7 did not induce synovial fibrosis, ectopic bone, or osteophyte formation. As detected by enzyme-linked immunosorbent assay, BMP-7 concentration in the cartilage tissue was still higher in the BMP-7 treated group 7 days after the injection. CONCLUSIONS: Weekly intra-articular injections of BMP-7 inhibited progression of osteoarthritis. Obvious adverse effects were not observed. BMP-7 concentration and expression in cartilage were still higher 7 days after injection.