Recombinant Human Bone Morphogenetic Protein-2 Research Articles

Blockage of undesirable endocytosis of recombinant human growth/differentiation factor-5 in Chinese hamster ovary cell cultures requires heparin analogs with specific chain lengths.

Cell surface heparan sulfate proteoglycan (HSPG)-mediated endocytosis lowers the yield of recombinant human bone morphogenetic proteins (rhBMPs), such as rhBMP-2 and rhBMP-4, from Chinese hamster ovary (CHO) cell cultures. Exogenous recombinant human growth/differentiation factor-5 (rhGDF-5), a member of the BMP family, bound to cell surface HSPGs and was actively internalized into CHO cells. Knockdown of heparan sulfate (HS) synthesis enzymes in CHO cells revealed that the chain length and N-sulfation of HS affected the binding of rhGDF-5 to HSPGs and subsequent rhGDF-5 internalization. To increase product yield by minimizing rhGDF-5 internalization in recombinant CHO (rCHO) cell cultures, heparin, and dextran sulfate (DS) of various polysaccharide chain lengths, which are structural analogs of HS, were examined for blockage of rhGDF-5 internalization. Heparin fragments of four monosaccharides (MW of 1.2kDa) and DS (MW of 15kDa) did not inhibit rhGDF-5 internalization whereas unfractionated heparin and DS of 200kDa could significantly inhibit it. Compared to the control cultures, supplementation with unfractionated heparin or DS of 200kDa at 1g L-1 resulted in more than a 10-fold increase in the maximum rhGDF-5 concentration. Taken together, the supplementation of structural HS analogs improved rhGDF-5 production in rCHO cell cultures by inhibiting rhGDF-5 internalization.

19. Anterior lumbar interbody fusion with porous titanium interbody cages is associated with equivalent fusion rates and patient reported outcomes as bone morphogenetic protein-2

<h3>BACKGROUND CONTEXT</h3> Although frequently used for anterior lumbar interbody fusion (ALIF), concerns regarding the use of recombinant human bone morphogenetic protein 2 (BMP-2) include off-label use, elevated cost and adverse outcomes such as osteolysis. The growing evolution of porous implant technology in promoting osseous integration via ingrowth provides an opportunity for a paradigm shift by relying less on biologic-assisted through-growth and leveraging implant on-growth and in-growth in similar fashion to porous metallic implants used in other orthopedic settings such as hip arthroplasty. <h3>PURPOSE</h3> This study compared perioperative clinical and radiographic outcomes between patients undergoing ALIF with the assistance of BMP-2 in a nonporous, traditional window interbody cage vs those with no biologic using a minimal-window porous titanium interbody cage. <h3>STUDY DESIGN/SETTING</h3> Retrospective clinical. <h3>PATIENT SAMPLE</h3> This study retrospectively examined 75 consecutive patients who underwent 1- or 2-level ALIF between 2014 and 2020 with the use of BMP-2 in a nonporous PEEK cage vs a porous titanium interbody cage and no biologic. All patients had surgery with the senior surgeon and were followed for a minimum follow-up of 6-months postoperatively. <h3>OUTCOME MEASURES</h3> Patient demographics, comorbidities, postoperative complications, and preoperative, immediate and final postoperative patient-reported outcomes (PROs) were assessed. Rates of reoperation were recorded, and arthrodesis was evaluated using Bridwell radiographic criteria and CT when available. Pre- and postoperative radiographic parameters were evaluated for differences in spinopelvic alignment and correction. <h3>METHODS</h3> Statistical methods included student's t-test and chi-square for continuous and categorical variables, respectively. Continuous variables were reported as means and standard deviations, and categorical variables as proportions. The threshold for statistical significance was set to p < .05. <h3>RESULTS</h3> Forty-three (13 female, 30 male) and 32 (19 female, 13 male) patients were assessed in the BMP-2 and titanium cage cohorts, respectively. On PRO assessment, baseline VAS leg among BMP-2 patients (6.87, SD: 1.96 vs 5.16, SD: 2.41; p = .023) while the titanium cage group reported worse VAS back scores (6.23, SD: 2.39 vs 7.82, SD: 1.40; p = .023). However, there were no significant differences recorded in postoperative PRO surveys between groups. Correction of spinopelvic alignment was equally maintained between groups at final follow-up when compared to immediate postoperative radiographs. Similarly, disc spaces were equivalently upheld across cohorts, with the exception of greater degeneration among BMP-2 patients at the L4-L5 anterior (-1.78, SD: 3.00 vs -0.07, SD: 2.63; p = .039) and foraminal (-2.34, SD: 3.11 vs -0.07, SD: 2.06; p = .006) disc spaces. Interbody subsidence was similar at the superior (1.13, SD: 0.84 vs 1.28, SD: 0.88; p = .458) and inferior endplates (0.55, SD: 0.79 vs 0.91, SD: 1.27; p = .154), and radiographic evidence of fusion was observed at equivalent rates (90% vs 90.9%, p = .776). There were no differences in the rates of secondary surgeries for adjacent segment disease (ASD) (4.6% vs 0%, p = .222) or index-level revisions (9.1% vs 18.8%, p = .219). <h3>CONCLUSIONS</h3> Porous titanium interbody cages for ALIF may be equivalent to BMP-2 in nonporous PEEK in achieving arthrodesis, alignment durability and reoperation rates. Although long-term follow-up is necessary, the use of porous titanium implants without external biologics is an intriguing paradigm change which may produce similar outcomes at lower costs. <h3>FDA DEVICE/DRUG STATUS</h3> Alphatec Identiti Cage (Approved for this indication), Recombinant Human Bone Morphogenetic Protein-2 (Approved for this indication)

115. Is the use of rh-BMP associated with increased incidence of cancer?

<h3>BACKGROUND CONTEXT</h3> Recombinant human bone morphogenetic protein (rhBMP) is frequently used in spinal arthrodesis to stimulate bone fusion. However, there is a potential concern for rhBMP in the promotion of tumor growth due to presence of BMP receptors on a variety of cancer cells. <h3>PURPOSE</h3> The study was conducted to determine if there is an increased risk of developing cancer after exposure to rhBMP and if the risk is dose and/or exposure dependent. <h3>STUDY DESIGN/SETTING</h3> Level I evidence. <h3>PATIENT SAMPLE</h3> This study included 467,916 patients. <h3>OUTCOME MEASURES</h3> Incidence of cancer. <h3>Methods</h3> We conducted a systematic review of electronic databases using different MeSH terms from 2000 to 2020. Pooled and subgroup analyses were performed using fixed and random effect models based upon the heterogeneity (I2). The results were reported as odds ratio (OR) with 95% confidence interval (CI). Further scatter log plot was conducted to determine the dose-response relationship between rh-BMP and incidence of cancer. <h3>Results</h3> A total of 467,916 patients from 25-studies (10 randomized controlled trials, 14 retrospective cohort studies and 1 case-control study) were included. In our study, 110,808 patients (62.5% females) received rhBMP while the remaining 357,108 patients (58.4% females) were in the control group. There was no statistically significant difference in terms of age (p=0.37), body mass index (p=0.51) and mean follow-up (p=0.28) between the two groups. There did not exist any statistically significant difference in terms of cancer incidence between the treatment and control group (OR: 95% CI: 0.63-4.36, p=0.30). However, the patients receiving rhBMP2 had significantly higher risk of cancer than those receiving rh BMP7 (p=0.03) at a mean follow-up of 33.5±20.2 months. Furthermore, lower doses of rhBMP were associated with none-to-minimal incidence of cancer while those receiving higher doses were associated with increased risk of cancer. The steepest point of the dose-response curve corresponded with an EC50 of 8mg rhBMP. <h3>Conclusions</h3> Our study did not demonstrate any risk of tumorigenesis or metastasis with rhBMP administration compared to the placebo group. However, there was a dose-dependent correlation of rhBMP with cancer. Further prospective studies are needed to validate our results. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Serial administration of rhBMP-2 and alendronate enhances the differentiation of osteoblasts.

The incorporation of growth factors is an effective strategy to accelerate bone induction. Bone morphogenetic protein-2 (BMP-2) promotes osteoblast differentiation and induces bone formation. Alendronate (ALN) is an osteoclast deactivation drug. We investigated the effect of serial administration of recombinant human BMP-2 (rhBMP-2) and ALN on osteoblast differentiation. The effect of serial administration of rhBMP-2 (0-150ng/mL) and ALN (0-15µmol/L) on the viability and differentiation of a clonal murine calvarial cell line, MC3T3-E1, was evaluated at various concentrations and for different periods. The Cell Counting Kit-8 assay was used to assess cell viability. The alkaline phosphatase activity was evaluated as an indicator of osteogenic differentiation. The expression levels of runt domain-containing transcription factor 2 (Runx2) and osteopontin (OPN) were analyzed by real-time polymerase chain reaction and western blotting. Statistical analyses were performed using Student's t test. The serial treatment with rhBMP-2 and ALN increased the expression of the differentiation-related factors Runx2 and OPN, as well as the differentiation ability of osteoblasts compared with individual or simultaneous treatment. The osteoblasts treated with rhBMP-2 followed by ALN showed the highest differentiation. The degree of differentiation in the group treated with rhBMP-2 for 7days followed by ALN for 3days was increased by 1.5 times compared with that of the group treated with rhBMP-2 alone (P<.01). These findings indicate that the serial administration of rhBMP-2 and ALN may exert osteogenic effects on osteoblastic cells via the upregulation of Runx2 and OPN.

Onlay-graft of 3D printed Kagome-structure PCL scaffold incorporated with rhBMP-2 based on hyaluronic acid hydrogel

The onlay-graft, one of the most difficult graft conditions, is used for diverse clinical conditions, including plastic and dental surgery. The graft should withstand continuous pressure from overlying tissues and have excellent bone formation capability in a limited bone contact situation. We recently developed a 3D printed Kagome-structured polycaprolactone (PCL) scaffold that has a stronger mechanical property. This study evaluated the clinical feasibility of this scaffold for onlay-graft use. The value of the scaffold containing recombinant human bone morphogenetic protein-2 in a hyaluronate-based hydrogel (rhBMP-2/HA) to enhance bone regeneration was also assessed. 3D-printed Kagome-PCL scaffolds alone (n = 12, group I) or loaded with rhBMP-2/HA (n = 12, group II) were grafted using a rat calvarial onlay-graft model. Following sacrifice at 2, 4, and 8 weeks, all 3D-printed Kagome-PCL scaffolds were accurately positioned and firmly integrated to the recipient bone. Micro-computed tomography and histology analyses revealed a constant height of the scaffolds over time in all animals. New bone grew into the scaffolds in both groups, but with greater volume in group II. These results suggest the promising clinical feasibility of the 3D-printed Kagome-PCL scaffold for onlay-graft use and it could substitute the conventional onlay-graft in the plastic and dental reconstructive surgery in the near future.

Nano-Hydroxyapatite Scaffold Based on Recombinant Human Bone Morphogenetic Protein 2 and Its Application in Bone Defect Repair.

The best way in which to prepare scaffolds with good biological properties is an urgent problem in the field of tissue engineering. In this paper we discuss the preparation of nano-hydroxyapatite scaffold of recombinant human bone morphogenetic protein-2 (rhBMP-2) and its application in bone defect repair. rhBMP-2 reagent was dissolved in 1 mol/L sodium dihydrogen phosphate solution, and the rhBMP-2 solution was added to the nano-hydroxyapatite artificial bone with a 100 μL glass micro dropper at the rate of 10 drops/min to obtain Nano-HA/rhBMP-2 composite artificial bone. In in vivo experiments, rabbits were fixed on an operating table, a 2 cm longitudinal incision was made in the middle part of the radial forearm, and the radius was cut with a wire saw and periosteum, 2.5 cm away from the distal radius. After washing the wound with normal saline, Adv-hBMP-2/MC3T3-E1 nano-HA composite artificial bone, MC3T3-E1 nan-HA composite artificial bone, or Nano-HA artificial bone were implanted in different groups. The artificial bone scaffold prepared in this study has a stronger ability to repair bone defects than the alternatives, and is a promising prospect for the clinical treatment of bone defects.

The Effect of Recombinant Human Bone Morphogenetic Protein-7 (rhBMP-7) on the osteoblast-like cells cultured on implant titanium discs

The Effect of Recombinant Human Bone Morphogenetic Protein-7 (rhBMP-7) on the osteoblast-like cells cultured on implant titanium discs

Wingless-type mouse mammary tumor virus integration site regulation of bovine theca cells.

Ovarian paracrine mediation by components of the wingless-type mouse mammary tumor virus integration site ligands (WNT1 to 11) and their receptors, frizzled family members (FZD1 to 10), has been proposed. Secreted truncated forms of FZD proteins (e.g., secreted frizzled-related protein 4 [SFRP4]) block the action of WNT ligands. Dickkopf-1 (DKK1) is another WNT antagonist, and R-spondin-1 (RSPO1) is one of a group of four secreted proteins that enhance WNT/β-catenin signaling. Our hypothesis was that granulosa cells signal theca cells (TCs) via SFRP4, DKK1, RSPO1, and WNT secretion to regulate TC differentiation and proliferation. Therefore, in vitro experiments were conducted to study the effects of WNT family member 3A (WNT3A), WNT5A, RSPO1, DKK1, insulin-like growth factor 1 (IGF1), bone morphogenetic protein 7 (BMP7), Indian hedgehog (IHH), and fibroblast growth factor 9 (FGF9) on bovine TC proliferation and steroidogenesis. TCs of large (8 to 20 mm) and small (3 to 6 mm) follicles were collected from bovine ovaries; TC monolayers were established in vitro and treated with various doses of recombinant human WNT3A, WNT5A, RSPO1, DKK1, IGF1, FGF9, BMP7, IHH, and/or ovine luteinizing hormone (LH) in serum-free medium for 48 h. In experiment 1, using LH-treated TC, IGF1, IHH, and WNT3A increased (P < 0.05) cell numbers and androstenedione production, whereas WNT3A and BMP7 inhibited (P < 0.05) progesterone production. In experiment 2, FGF9 blocked (P < 0.05) the WNT3A-induced increase in androstenedione production in LH plus IGF1-treated TC. In experiment 3, RSPO1 further increased (P < 0.05) LH plus IGF1-induced progesterone and androstenedione production. In experiment 4, SFRP4 and DKK1 alone had no significant effect on TC proliferation or progesterone production of large-follicle TC but both blocked the inhibitory effect of WNT5A on androstenedione production. In contrast, DKK1 alone inhibited (P < 0.05) small-follicle TC androstenedione production whereas SFRP4 was without effect. We conclude that the ovarian TC WNT system is functional in cattle, with WNT3A increasing proliferation and androstenedione production of TC.

Three-dimensionally printed porous biomimetic composite for sustained release of recombinant human bone morphogenetic protein 9 to promote osteointegration

Three-dimensionally printed porous titanium alloys prepared using the electron beam melting (EBM) technology have customized structures and a low elastic modulus. They can promote the repair of bone defects. Growth factors can enhance the biological activity of plants in vivo, and bone morphogenetic protein 9 (BMP9) is the key factor for osteogenesis. The purpose of this study was to evaluate a porous titanium implant prepared using the EBM technology with temperature-sensitive collagen mixed with recombinant human (rh) BMP9 as a composite scaffold to be continuously provided to enhance osteogenesis in rabbit femoral defects. The in vitro experiments verified cell proliferation, proliferation and application of the composite stent, the degree of release of temperature-sensitive collagen to rhBMP9, and the osteogenesis-inducing effect of the composite stent on bone marrow mesenchymal stem cells. In vivo, the rabbit femoral defect model was used to evaluate the effects of the composite on osteointegration and bone ingrowth. The results showed that the composite scaffold had good biocompatibility and provided bioactive growth factors for bone repair. Further, the release of rhBMP9 significantly enhanced osteogenesis in and around the porous scaffolds. This method helps to study bioactive coating on the titanium alloy surface of patients with bone defects.

Engineered bridge protein with dual affinity for bone morphogenetic protein-2 and collagen enhances bone regeneration for spinal fusion.

The revolutionizing efficacy of recombinant human bone morphogenetic protein (rhBMP-2) for clinical spinal fusion is hindered by safety issues associated with the high dose required. However, it continues to be widely used, for example, in InFUSE Bone Graft (Medtronic). Here, we developed a translational protein engineering-based approach to reduce the dose and thereby improve the safety of rhBMP-2 delivered in a collagen sponge, as in InFUSE Bone Graft. We engineered a bridge protein with high affinity for rhBMP-2 and collagen that can be simply added to the product's formulation, demonstrating improved efficacy at low dose of rhBMP-2 in two mouse models of bone regeneration, including a newly developed spinal fusion model. Moreover, the bridge protein can control the retention of rhBMP-2 from endogenous collagenous extracellular matrix of tissue. Our approach may be generalizable to other growth factors and collagen-based materials, for use in many other applications in regenerative medicine.

Effectiveness of xenogeneic and synthetic bone-block substitute materials with/without recombinant human bone morphogenetic protein-2: A preclinical study using a rabbit calvarium model.

To investigate new bone (NB) formation by using bone-block substitute materials with/without recombinant human bone morphogenetic protein-2 (rhBMP-2). Three synthetic bone-block substitute materials [biphasic calcium phosphate (BCP); nanostructured hydroxyapatite (NH); 3D-printed tricalcium phosphate/hydroxyapatite (3DP)] and one xenogeneic deproteinized bovine bone mineral (DBBM) block substitute were affixed to rabbit calvarium using osteosynthesis screws, either with rhBMP-2 (n=12) or without rhBMP-2 (n=16). At 2 or 12weeks (n=6 with rhBMP-2 and n=8 without rhBMP-2 for each week), histologic, histomorphometric and microcomputed tomography analyses were performed. The application of rhBMP-2 increased NB formation in all experimental groups at both weeks. DBBM resulted in a greater area of NB compared with synthetic blocks either with or without rhBMP-2 at 2weeks (2.8±0.9 vs. 1.4±0.5-1.9±1.4mm2 ; 1.4±1.0 vs. 0.6±0.3-0.9±0.5mm2 ) and without rhBMP-2 at 12weeks (3.0±0.8 vs. 1.7±0.7-2.6±1.5mm2 ) (p>0.05). NB formation did not differ significantly for DBBM and the three types of synthetic block with rhBMP-2 at 12weeks (4.5±2.0 vs. 3.8±0.7-5.1±1.1mm2 ; p>0.05). rhBMP-2 enhanced NB in all blocks. DBBM blocks yielded more NB than synthetic blocks without rhBMP-2. The application of rhBMP-2 appears to compensate for differences in late healing.

Rehabilitation of Severely Atrophic Mandible: A 3-Year Follow-Up Protocol.

Severe bone atrophies are considered a challenge in the rehabilitation process. In clinical situations involving excessive vertical bone deficiency in edentulous mandibles, there is a risk of fracture and frequently the need for an approach that involves highly complex procedures. In this context, simultaneous three-dimensional bone reconstruction associated with rigid fixation is a viable alternative to optimize longevity and avoid failures in these cases. This clinical case report presents a technique for reconstruction of severely atrophic mandibles in an elderly female patient to allow the implant-supported prosthesis protocol. The placement of immediate implants was possible by using an intraoral approach for fixation of a titanium plate followed by guided bone regeneration in association with recombinant human bone morphogenetic protein-2, deproteinized bovine bone mineral, and titanium mesh in a 1-stage surgical procedure. There are no reports in the literature of this approach for treating of severely atrophic mandibles. This association of techniques was shown to be predictable after 3 years of follow-up. Therefore, this protocol provides safe supported-implant prosthesis rehabilitation for patients with severely atrophic mandible.

Use of rhBMP-2 for adult spinal deformity surgery: patterns of usage and changes over the past decade.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to increase fusion rates; however, cost, limited FDA approval, and possible complications impact its use. Decisions regarding rhBMP-2 use and changes over time have not been well defined. In this study, the authors aimed to assess changes in rhBMP-2 use for adult spinal deformity (ASD) surgery over the past decade. A retrospective review of the International Spine Study Group prospective multicenter database was performed to identify ASD patients treated surgically from 2008 to 2018. For assessment of rhBMP-2 use over time, 3 periods were created: 2008-2011, 2012-2015, and 2016-2018. Of the patients identified, 1180 met inclusion criteria, with a mean age 60 years and 30% of patients requiring revision surgery; rhBMP-2 was used in 73.9% of patients overall. The mean rhBMP-2 dose per patient was 23.6 mg. Patients receiving rhBMP-2 were older (61 vs 58 years, p < 0.001) and had more comorbidities (Charlson Comorbidity Index 1.9 vs 1.4, p < 0.001), a higher rate of the Scoliosis Research Society-Schwab pelvic tilt modifier (> 0; 68% vs 62%, p = 0.026), a greater deformity correction (change in pelvic incidence minus lumbar lordosis 15° vs 12°, p = 0.01), and more levels fused (8.9 vs 7.9, p = 0.003). Over the 3 time periods, the overall rate of rhBMP-2 use increased and then stabilized (62.5% vs 79% vs 77%). Stratified analysis showed that after an overall increase in rhBMP-2 use, only patients who were younger than 50 years, those who were smokers, those who received a three-column osteotomy (3CO), and patients who underwent revision sustained an increased rate of rhBMP-2 use between the later two periods. No similar increases were noted for older patients, nonsmokers, primary surgery patients, and patients without a 3CO. The total rhBMP-2 dose decreased over time (26.6 mg vs 24.8 mg vs 20.7 mg, p < 0.001). After matching patients by preoperative alignment, 215 patients were included, and a significantly lower rate of complications leading to revision surgery was observed within the 2012-2015 period compared with the 2008-2011 (21.4% vs 13.0%, p = 0.029) period, while rhBMP-2 was increasingly used (80.5% vs 66.0%, p = 0.001). There was a trend toward a lower rate of pseudarthrosis for patients in the 2012-2015 period, but this difference did not reach statistical significance (7% vs 4.2%, p = 0.283). The authors found that rhBMP-2 was used in the majority of ASD patients and was more commonly used in those with greater deformity correction. Additionally, over the last 10 years, rhBMP-2 was increasingly used for ASD patients, but the dose has decreased.

Safety and efficacy of low-dose rhBMP-2 use for anterior cervical fusion.

The use of recombinant human bone morphogenetic protein 2 (rhBMP-2) in routine anterior cervical fusion (ACF) is controversial. Early reports described high complication rates. A variety of dosing regimens ranging from 0.6 to 2.1 mg per level fused have been reported. The authors hypothesized that the high amounts of rhBMP-2 used in these studies led to the high complication rates observed; therefore, they set out to evaluate the safety and efficacy of low-dose rhBMP-2 for use in ACFs. Patient inclusion criteria were 1) age 18 to 70 years; 2) initial stand-alone ACF construct; 3) fusion augmentation with rhBMP-2; and 4) at least 1 year of radiographic follow-up. A successful fusion was defined by either 1) lateral flexion-extension radiographs with less than 1 mm of movement across the fused spinous processes, or 2) bone bridging at least half of the fusion area originally achieved by surgery on fine-cut CT. Patient demographics, perioperative data, and postoperative complications were recorded. A total of 198 patients met the inclusion criteria and were included for analysis. Sixty-two patients (31%) were smokers. The median number of levels fused was 2 (IQR 1.25). The mean dose of rhBMP-2 was 0.50 ± 0.09 mg per level. Twenty-two (11%) patients experienced dysphagia. Eleven (6%) patients experienced cervical swelling. Two (1%) patients returned to the operating room (OR) for postoperative hematoma. One (0.5%) patient returned to the OR for seroma. Two (1%) patients experienced pseudarthrosis requiring a posterior fusion. Three (2%) patients experienced a new postoperative neurological deficit that had recovered by last the follow-up. Overall, 190 (96%) patients experienced solid arthrodesis over an average of 15 months of follow-up. There was no difference in fusion rates between patients who were either smokers or nonsmokers (p = 0.7073). The use of low-dose rhBMP-2 safely and effectively augmented anterior cervical arthrodesis. The low-dose protocol assessed in this study appeared to significantly reduce complications associated with rhBMP-2 use in ACF compared with the literature. The authors have determined that using low-dose rhBMP-2 in patients who are smokers, those with multilevel ACFs, or others at high risk of developing pseudarthrosis is recommended.

Effect of total flavonoids from Drynaria rhizome on bone loss in ovariectomized rats

Purpose: To determine the potential effect of total flavonoids from Drynaria rhizome on bone loss in ovariectomized (OVX) rats.&#x0D; Methods: The rats were divided into four groups: normal control, ovariectomized (OVX) control, and two Drynaria rhizome (DR) flavonoids treatments. Post-operation, osteoporotic OVX rats were given Drynaria rhizome total flavonoids for 3 months. Thereafter, the expressions of bone-related genes and biochemical indices were investigated in samples taken from the serum and bone of the rats.&#x0D; Results: Treatment with total flavonoids from Drynaria rhizome prevented bone mineral loss and improved some related biochemical indices associated with osteoporosis: alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP), bone gla protein (BGP) and estradiol (E2). Reverse transcription-polymerase chain reaction (RT-PCR) data showed that treatment with the total flavonoids significantly downregulated mRNA expression of Wnt10b, β-catenin, recombinant human bone morphogenetic protein-2 (BMP2) and BMP4 in OVX rats, but significantly reversed OVX-induced downregulation of dickkopf1 (Dkk1) mRNA expression.&#x0D; Conclusion: These results indicate that total flavonoids from Drynaria rhizome exert anti-osteoporotic effects in rats via WNT signaling and BMP-2 signaling pathways.

Effect of total flavonoids from Drynaria rhizome on bone loss in ovariectomized rats

Purpose: To determine the potential effect of total flavonoids from Drynaria rhizome on bone loss in ovariectomized (OVX) rats.&#x0D; Methods: The rats were divided into four groups: normal control, ovariectomized (OVX) control, and two Drynaria rhizome (DR) flavonoids treatments. Post-operation, osteoporotic OVX rats were given Drynaria rhizome total flavonoids for 3 months. Thereafter, the expressions of bone-related genes and biochemical indices were investigated in samples taken from rat serum and bone.&#x0D; Results: Treatment with total flavonoids from Drynaria rhizome prevented bone mineral loss and improved some related biochemical indices associated with osteoporosis, namely, alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP), bone gla protein (BGP) and estradiol (E2). Reverse transcription-polymerase chain reaction (RT-PCR) data showed that treatment with the total flavonoids significantly downregulated mRNA expression of Wnt10b, β-catenin, recombinant human bone morphogenetic protein-2 (BMP2) and BMP4 in OVX rats, but significantly reversed OVX-induced downregulation of dickkopf1 (Dkk1) mRNA expression.&#x0D; Conclusion: These results indicate that total flavonoids from Drynaria rhizome exert anti-osteoporotic effects in rats through the WNT signaling and BMP-2 signaling pathways.

Functionally assembled metal platform as lego-like module system for enhanced mechanical tunability and biomolecules delivery

Natural bone substituting materials derived from living organisms have been utilized to treat bone malfunctioning. However, limited sources and immune issues have led to the use of artificial scaffolds consisting of biocompatible materials. Additionally, a functionally graded porous structure has been acknowledged as an alternative to overcome reduced mechanical properties by pores and alleviate stress shielding effect. In this study, a two-body combination achieved through a densification process, in which recombinant human bone morphogenetic protein-2 (rhBMP-2) and tetracycline hydrochloride (TCH) can be simultaneously released for efficient bone regeneration, is proposed. Biomimetic titanium scaffolds (BTSs), which possess significantly different pore characteristics, are successfully fabricated. The mechanical properties of these parts are proven to be applicable as bone substitutes. The release of rhBMP-2 and TCH from the BTSs is prolonged compared to that of homogenous porous titanium scaffolds (PTSs). The prolonged release of rhBMP-2 from the BTS results in a sustained degree of pre-osteoblast differentiation. The antimicrobial properties of these scaffolds are verified using pathogens. Furthermore, various structures exhibiting different pore characteristics are obtained by mechanical interlocking between components. This study demonstrates that the novel assembled platform as customizable Lego-like building blocks, with its tunable mechanical and multi-biomolecule release properties, is promising for bone tissue engineering.

Surface chemical modification of poly(phthalazinone ether nitrile ketone) through rhBMP-2 and antimicrobial peptide conjugation for enhanced osteogenic and antibacterial activities in vitro and in vivo

Failure of poly(aryl ether ketone) (PAEK) bone implants results mainly from poor osteogenesis and bacterial infection. One promising strategy for enhancing osteointegration involves developing a bioactive surface of PAEK implants through chemical modification. Poly(phthalazinone ether nitrile ketone) (PPENK) is considered a potential PAEK bone implant because it possesses mechanical properties similar to those of natural bone and its cyano group has high reactivity which provides a surface modification strategy. In this work, recombinant human bone morphogenetic protein-2 (rhBMP-2) and newly synthesized cationic antimicrobial polypeptides (AMPs) were chemically conjugated to a PPENK substrate surface to enhance osteogenic and antibacterial activities. The molecular structures of AMP-1 and AMP-2 containing PEG segments were confirmed by nuclear magnetic resonance spectroscopy. The surface roughness of each substrate was reduced by rhBMP-2 and AMP immobilization. In situ, real-time quartz crystal microbalance with dissipation studies revealed that the loading amount increased with the successive immobilization of rhBMP-2 and AMPs. In vitro antibacterial assay confirmed that the AMP-modified PPENK surfaces provided an effective antibacterial effect and the number of residential bacteria remaining on the substrate was reduced by the PEG segments in AMP-2. In vitro osteogenic properties of the rhBMP-2-modified PPENK surface presented favorable cytocompatibility and osteo-inductive activity. In vivo studies confirmed that the rhBMP-2 and AMP immobilization led to decrease amounts of fibrous tissues around the implant and improved bone regeneration. This study provides a strategy for surface modification that enhances the antibacterial and osteogenic activities to develop a bone implant material with considerable potential for clinical application.

Clinical study of calcium phosphate cement loaded with recombinant human bone morphogenetic protein 2 combined with calcium phosphate cement loaded with antibiotic for chronic osteomyelitis with bone defect

To compare the effectiveness of calcium phosphate cement (CPC) loaded with recombinant human bone morphogenetic protein 2 (rhBMP-2) combined with CPC loaded with antibiotic versus CPC loaded with antibiotic alone in one stage for chronic osteomyelitis with bone defect. A single-blind prospective randomized controlled clinical trial was conducted. Between April 2018 and April 2019, 80 patients of chronic osteomyelitis with bone defect in accordance with the random number table were randomly divided into two groups, 40 in the trial group (CPC loaded with rhBMP-2 combined with CPC loaded with antibiotic) and 40 in the control group (CPC loaded with antibiotic). There was no significant difference in gender, age, disease duration, lesion, and preoperative white blood cells (WBC) count, platelet count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) between the two groups ( P>0.05). All patients were implanted the corresponding CPC and external fixator after lesion clearance in the two groups. The postoperative WBC count, platelet count, ESR, CRP, hospital stay, cure rate of osteomyelitis, repaired bone defect volume, the time of external fixator removal, and the time of full weight-bearing of the affected limb were compared between the two groups. All patients were followed up 12-24 months, with an average of 18.4 months. There was no significant difference in WBC count, platelet count, ESR, and CRP between the two groups at 4 weeks after operation ( P>0.05). There were significant differences in WBC count, platelet count, and CRP in the two groups between 1 week before operation and 4 weeks after operation ( P<0.05). And the ESR showed no significant difference between pre- and post-operation in the two groups ( P>0.05). In the trial group, the anaphylactic exudate occurred in 1 patient with tibial osteomyelitis and the incision healed after oral administration of loratadine. The incisions of other patients healed by first intention in the two groups. One case of distal tibial osteomyelitis recurred in each group, and 1 case of humeral osteomyelitis recurred in the control group. The cure rates of osteomyelitis were 97.5% (39/40) in the trial group and 95% (38/40) in the control group, showing no significant difference between the two groups ( χ 2 =0.000, P=1.000). There was no significant difference in the repaired bone defect volume and hospital stay between the two groups ( P>0.05). X-ray film and CT showed that the bone defects were repaired in the two groups. The time of external fixator removal and the time of full weight-bearing of the affected limb were significantly shorter in the trial group than in the control group ( P<0.05). Application of CPC loaded with rhBMP-2 and antibiotic in one stage is effective for the chronic osteomyelitis with bone defect, which can accelerate the bone regeneration in situ to repair bone defect, reduce the trauma, shorten the course of treatment, and obtain good function of the affected limb.

In ovariectomy-induced osteoporotic rat models, BMP-2 substantially reversed an impaired alveolar bone regeneration whereas PDGF-BB failed

We previously suggested an ovariectomy (OVX)-induced osteoporotic rat model showing an impaired alveolar bone defect healing. This study aimed to evaluate and compare the effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB) on alveolar bone defect healing in OVX-induced osteoporotic rats. A total of forty-one female rats were divided into four groups: a collagen group (n=10), a PDGF-BB group (n=11), a BMP-2 group (n=10), and a control group (n=10). Four months after OVX, alveolar bone drill-hole defects were created and grafted with collagen gel, rhPDGF-BB/collagen gel, or rhBMP-2/collagen gel. The defects in the control group were not grafted with any material. Defect healing was evaluated by histological, histomorphometric, and microcomputed tomographic (micro-CT) analyses at 2 and 4 weeks. According to the micro-CT analysis, the BMP-2 group exhibited the greatest bone volume fraction among all groups, while the PDGF-BB group did not show significant differences compared with the collagen group. The histomorphometric analysis showed a significantly larger amount of new bone area in the BMP-2 group than in the control and collagen groups at 4 weeks; however, the PDGF-BB group did not reach significant superiority compared with the other groups. Alveolar bone regeneration was significantly enhanced by the local use of rhBMP-2/collagen gel compared with the use of rhPDGF-BB/collagen gel in OVX-induced osteoporotic rats. A treatment modality using rhBMP-2 may be a promising approach to promote alveolar bone regeneration in patients suffering from postmenopausal osteoporosis.