Distinctive Expression of Bone Metabolism-related Genes between PBMCs from Condylar Hyperplasia, Rheumatoid Arthritis, and Ankylosing Spondylitis Patients

Bone morphogenetic proteins (BMPs) and wingless (Wnt) signaling molecules and their antagonists, such as sclerostin and noggin, have been identified to have different effects on bone metabolism. This research intended to evaluate the transcript levels of CTNNB1 (catenin beta 1protein), SOST (sclerostin protein), BMP4 (Bone Morphogenetic Protein 4 protein), and NOG (noggin protein) bone metabolism-related genes in peripheral blood mononuclear cells (PBMCs) from condylar hyperplasia (CH) patients in comparison to rheumatoid arthritis (RA), ankylosing spondylitis (AS), and healthy individuals. PBMCs were separated from blood samples of 10 patients with CH, AS, RA, and 10 healthy controls. SYBR Green real-time polymerase chain reaction (PCR) was used for quantitative analysis of CTNNB1, SOST, BMP4, and NOG messenger RNAs (mRNAs). The expression of CTNNB1 was significantly upregulated in CH and AS patients compared with healthy individuals and RA patients. The difference of SOST expression was not significant between all groups. The BMP4 expression was significantly downregulated in AS, CH, and RA patients compared with healthy controls. The NOG expression was downregulated in RA, AS, and CH groups, however, it was only significant in CH and RA patients compared with controls.CH and AS patients were distinguished from RA by the upregulatedCTNNB1 expression. These results demonstrated that CTNNB1, BMP4, and NOG, but not SOST, may contribute to the pathogenesis of CH, AS, and RA.

Opposing and potentially antagonistic effects of BMP and TGF-β in multiple sclerosis: The "Yin and Yang" of neuro-immune Signaling

Bone Morphogenetic Proteins (BMP) and Transforming Growth Factor-beta (TGF-β) are cytokines with similar receptors and messengers. They are important for immune cell function, with BMPs exerting mainly proinflammatory but also anti-inflammatory effects, and TGF-β suppressing inflammation. Patients with Multiple Sclerosis exhibit BMP overactivity and suppressed TGF-β signaling. This dysregulated signaling participates in the crosstalk between infiltrating immune cells and glia, where BMP inhibits remyelination. Reciprocal antagonism between the two pathways takes place via a variety of mechanisms. Although this antagonism has not been studied in the setting of Multiple Sclerosis, it could inform further research and treatment discovery.

Bone morphogenetic proteins: New insights into their roles and mechanisms in CNS development, pathology and repair

Bone morphogenetic proteins (BMPs) are a highly conserved and diverse family of proteins that play essential roles in various stages of development including the formation and patterning of the central nervous system (CNS). Bioavailability and function of BMPs are regulated by input from a plethora of transcription factors and signaling pathways. Intriguingly, recent literature has uncovered novel roles for BMPs in regulating homeostatic and pathological responses in the adult CNS. Basal levels of BMP ligands and receptors are widely expressed in the adult brain and spinal cord with differential expression patterns across CNS regions, cell types and subcellular locations. Recent evidence indicates that several BMP isoforms are transiently or chronically upregulated in the aged or pathological CNS. Genetic knockout and pharmacological studies have elucidated that BMPs regulate several aspects of CNS injury and repair including cell survival and differentiation, reactive astrogliosis and glial scar formation, axon regeneration, and myelin preservation and repair. Several BMP isoforms can be upregulated in the injured or diseased CNS simultaneously yet exert complementary or opposing effects on the endogenous cell responses after injury. Emerging studies also show that dysregulation of BMPs is associated with various CNS pathologies. Interestingly, modulation of BMPs can lead to beneficial or detrimental effects on CNS injury and repair mechanisms in a ligand, temporally or spatially specific manner, which reflect the complexity of BMP signaling. Given the significance of BMPs in neurodevelopment, a better understanding of their role in the context of injury may provide new therapeutic targets for the pathologic CNS. This review will provide a timely overview on the foundation and recent advancements in knowledge regarding the role and mechanisms of BMP signaling in the developing and adult CNS, and their implications in pathological responses and repair processes after injury or diseases.

What do we know about bone morphogenetic proteins and osteochondroprogenitors in inflammatory conditions?

Osteochondroprogenitors are crucial for embryonic bone development and postnatal processes such as bone repair in response to fracture injury, and their dysfunction may contribute to insufficient repair of structural damage in inflammatory arthritides. In the fracture healing, the early inflammatory phase is crucial for normal callus development and new bone formation. This process involves a complex interplay of many molecules and cell types, responsible for recruitment, expansion and differentiation of osteochondroprogenitor populations. In inflammatory arthritides, inflammation induces bone resorption and causes insufficient bone formation, which leads to local and systemic bone loss. While bone loss is a predominant feature in rheumatoid arthritis, inflammation also induces pathologic bone formation at enthesial sites in seronegative spondyloarthropathies. Bone morphogenetic proteins (BMP) are involved in cell proliferation, differentiation and apoptosis, and have fundamental roles in maintenance of postnatal bone homeostasis. They are crucial regulators of the osteochondroprogenitor pool and drive their proliferation, differentiation, and lifespan during bone regeneration. In this review, we summarize the effects of inflammation on osteochondroprogenitor populations during fracture repair and in inflammatory arthritides, with special focus on inflammation-mediated modulation of BMP signaling. We also present data in which we describe a population of murine synovial osteochondroprogenitor cells, which are reduced in arthritis, and characterize their expression of genes involved in regulation of bone homeostasis, emphasizing the up-regulation of BMP pathways in early progenitor subset. Based on the presented data, it may be concluded that during an inflammatory response, innate immune cells induce osteochondroprogenitors by providing signals for their recruitment, by producing BMPs and other osteogenic factors for paracrine effects, and by secreting inflammatory cytokines that may positively regulate osteogenic pathways. On the other hand, inflammatory cells may secrete cytokines that interfere with osteogenic pathways, proapoptotic factors that reduce the pool of osteochondroprogenitor cells, as well as BMP and Wnt antagonists. The net effect is strongly context-dependent and influenced by the local milieu of cells, cytokines, and growth factors. Further elucidation of the interplay between inflammatory signals and BMP-mediated bone formation may provide valuable tools for therapeutic targeting.

A multifaceted biomimetic interface to improve the longevity of orthopedic implants

The rise of additive manufacturing has provided a paradigm shift in the fabrication of precise, patient-specific implants that replicate the physical properties of native bone. However, eliciting an optimal biological response from such materials for rapid bone integration remains a challenge. Here we propose for the first time a one-step ion-assisted plasma polymerization process to create bio-functional 3D printed titanium (Ti) implants that offer rapid bone integration. Using selective laser melting, porous Ti implants with enhanced bone-mimicking mechanical properties were fabricated. The implants were functionalized uniformly with a highly reactive, radical-rich polymeric coating generated using a unique combination of plasma polymerization and plasma immersion ion implantation. We demonstrated the performance of such activated Ti implants with a focus on the coating's homogeneity, stability, and biological functionality. It was shown that the optimized coating was highly robust and possessed superb physico-chemical stability in a corrosive physiological solution. The plasma activated coating was cytocompatible and non-immunogenic; and through its high reactivity, it allowed for easy, one-step covalent immobilization of functional biomolecules in the absence of solvents or chemicals. The activated Ti implants bio-functionalized with bone morphogenetic protein 2 (BMP-2) showed a reduced protein desorption and a more sustained osteoblast response both in vitro and in vivo compared to implants modified through conventional physisorption of BMP-2. The versatile new approach presented here will enable the development of bio-functionalized additively manufactured implants that are patient-specific and offer improved integration with host tissue. STATEMENT OF SIGNIFICANCE: Additive manufacturing has revolutionized the fabrication of patient-specific orthopedic implants. Although such 3D printed implants can show desirable mechanical and mass transport properties, they often require surface bio-functionalities to enable control over the biological response. Surface covalent immobilization of bioactive molecules is a viable approach to achieve this. Here we report the development of additively manufactured titanium implants that precisely replicate the physical properties of native bone and are bio-functionalized in a simple, reagent-free step. Our results show that covalent attachment of bone-related growth factors through ion-assisted plasma polymerized interlayers circumvents their desorption in physiological solution and significantly improves the bone induction by the implants both in vitro and in vivo.

A new approach to the treatment of spinal instability: Fusion or structural reinforcement without surgery?

Spinal instability related low back pain is a common condition resulting from degeneration and loss of stiffness of the intervertebral joint. In order to restore stability, highly invasive surgical fusion is needed for patients who are not responding to conservative treatment. Given the risk and complications of surgery, there has been the urge for improvement with a less invasive solution. Formation of vertebral body osteophytes is a common observation that has been treated as a degenerative condition. However, recent studies have associated it with reduced motion of spinal segments. Unlike the traditional view, we regard it as adaptive reactions aiming to repair and hypothesize that the spinal segments could be stabilized or fused by intentionally induced osteophytes growth at the mobile parts of the intervertebral joint. This could be achieved by injecting Bone Morphogenetic Proteins to the anterior ends of the vertebral bodies and/or the facet joints on both sides of two consecutive vertebrae percutaneously. If verified, it would be the first time that fusion could be achieved without surgery. Hence it would provide a valuable alternative to current treatments of spinal instability. Preliminary test in favor of this hypothesis is presented and we recommend that a formal study with sufficient number of samples is needed for verification.

The role of hepatocyte growth factor in mesenchymal stem cell-induced recovery in spinal cord injured rats

Background

Mesenchymal stem cells (MSCs) have become a promising treatment for spinal cord injury (SCI) due to the fact that they provide a favorable environment. Treatment using MSCs results in a better neurological functional improvement through the promotion of nerve cell regeneration and the modulation of inflammation. Many studies have highlighted that the beneficial effects of MSCs are more likely associated with their secreted factors. However, the identity of the factor that plays a key role in the MSC-induced neurological functional recovery following SCI as well as its molecular mechanism still remains unclear.

Methods

A conditioned medium (collected from the MSCs) and hepatocyte growth factor (HGF) were used to test the effects on the differentiation of neural stem cells (NSCS) in the presence of BMP4 with or without a c-Met antibody. In SCI rats, Western blot, ELISA, immunohistochemistry, and hematoxylin-eosin staining were used to investigate the biological effects of MSC-conditioned medium and HGF on nerve cell regeneration and inflammation with or without the pre-treatment using a c-Met antibody. In addition, the possible molecular mechanism (cross-talk between HGF/c-Met and the BMP/Smad 1/5/8 signaling pathway) was also detected by Western blot both in vivo and in vitro.

Results

The conditioned medium from bone marrow-derived MSCs (BMSCs) was able to promote the NSC differentiation into neurons in vitro and the neurite outgrowth in the scar boundary of SCI rats by inhibiting the BMP/Smad signaling pathway as well as reduces the secondary damage through the modulation of the inflammatory process. The supplementation of HGF showed similar biological effects to those of BMSC-CM, whereas a functional blocking of the c-Met antibody or HGF knockdown in BMSCs significantly reversed the functional improvement mediated by the BMSC-CM.

Conclusions

The MSC-associated biological effects on the recovery of SCI rats mainly depend on the secretion of HGF.

Biomarkers of vascular calcification in serum

Over the last decades, the association between vascular calcification (VC) and all-cause/cardiovascular mortality, especially in patients with high atherogenic status, such as those with diabetes and/or chronic kidney disease, has been repeatedly highlighted. For over a century, VC has been noted as a passive, degenerative, aging process without any treatment options. However, during the past decades, studies confirmed that mineralization of the arteries is an active, complex process, similar to bone genesis and formation. The main purpose of this review is to provide an update of the existing biomarkers of VC in serum and develop the various pathogenetic mechanisms underlying the calcification process, including the pivotal roles of matrix Gla protein, osteoprotegerin, bone morphogenetic proteins, fetuin-a, fibroblast growth-factor-23, osteocalcin, osteopontin, osteonectin, sclerostin, pyrophosphate, Smads, fibrillin-1 and carbonic anhydrase II.

Inhibitors of Myelination and Remyelination, Bone Morphogenetic Proteins, are Upregulated in Human Neurological Disease

During demyelinating disease such as multiple sclerosis and stroke, myelin is destroyed and along with it, the oligodendrocytes that synthesize the myelin. Thus, recovery is limited due to both interruptions in neuronal transmission as well as lack of support for neurons. Although oligodendrocyte progenitor cells remain abundant in the central nervous system, they rarely mature and form new functional myelin in the diseased CNS. In cell culture and in experimental models of demyelinating disease, inhibitory signaling factors decrease myelination and remyelination. One of the most potent of these are the bone morphogenetic proteins (BMPs), a family of proteins that strongly inhibits oligodendrocyte progenitor differentiation and myelination in culture. BMPs are highly expressed in the dorsal CNS during pre-natal development and serve to regulate dorsal ventral patterning. Their expression decreases after birth but is significantly increased in rodent demyelination models such as experimental autoimmune encephalomyelitis, cuprizone ingestion and spinal cord injury. However, until recently, evidence for BMP upregulation in human disease has been scarce. This review discusses new human studies showing that in multiple sclerosis and other demyelinating diseases, BMPs are expressed by immune cells invading the CNS as well as resident CNS cell types, mostly astrocytes and microglia. Expression of endogenous BMP antagonists is also regulated. Identification of BMPs in the CNS is correlated with areas of demyelination and inflammation. These studies further support BMP as a potential therapeutic target.

Lipopolysaccharide (LPS) inhibits ectopic bone formation induced by bone morphogenetic protein-2 and TGF-β1 through IL-1β production

OBJECTIVES

In order to gain new insight into bacterial infection during bone-regenerative treatment using bone morphogenetic proteins (BMPs), we examined the effects of lipopolysaccharide (LPS) on ectopic bone formation induced by BMP-2 and transforming growth factor (TGF)-β1 in mice.

METHODS

We implanted collagen sponges containing BMP-2, TGF-β1, and various amounts of LPS into mouse muscle tissues. Lump-like masses in which ectopic bones developed in mice were processed for microcomputed tomography, DNA microarray, reverse-transcription PCR, and histological analyses.

RESULTS

LPS treatment caused a dose-dependent reduction in the volume of ectopic bone. The total volume of ectopic bone induced by BMP-2 + TGF-β1 treatment was reduced by more than 75% in the presence of LPS. Histological analysis of the ectopic bone tissues revealed a significant reduction in total bone volume and bone volume/total volume in response to LPS. LPS treatment significantly increased the osteoblast number and osteoid volume, while the osteoclast number did not change. Since LPS induced production of TNF-α and IL-1β in lump-like masses, we implanted collagen sponges containing BMP-2 and TGF-β1 with or without LPS into TNF-α- or IL-1α/β-deficient mice. LPS treatment reduced the volume of ectopic bones in TNF-α-deficient mice but not in IL-1α/β-deficient mice. Furthermore, collagen sponges containing IL-1β reduced ectopic bone formation by BMP-2 and TGF-β1 in wild-type mice to the same extent as LPS treatment did.

CONCLUSIONS

LPS suppresses the ectopic bone formation induced by BMP-2 and TGF-β1 through IL-1β production.

The role of hepcidin and iron homeostasis in atherosclerosis

Atherosclerotic cardiovascular disease is a major burden on global health and a leading cause of death worldwide. The pathophysiology of this chronic disease is complex, involving inflammation, lipoprotein oxidation and accumulation, plaque formation, and calcification. In 1981, Dr. Jerome Sullivan formulated the 'Iron Hypothesis', suggesting that higher levels of stored iron promote cardiovascular diseases, whereas iron deficiency may have an atheroprotective effect. This hypothesis has stimulated research focused on clarifying the role of iron in the development of atherosclerosis. However, preclinical and clinical studies have produced contradictory results and the observation that patients with hemochromatosis do not appear to have an increased risk of atherosclerosis seemed incongruous with Sullivan's initial hypothesis. The 'paradox' of systemic iron overload not being accompanied by an increased risk for atherosclerosis led to a refinement of the iron hypothesis focusing on intracellular macrophage iron. More recent in vitro and animal studies have elucidated the complex signaling pathways regulating iron, with a particular focus on hepcidin, the master regulator of body iron homeostasis. Bone morphogenetic protein (BMP) signaling is the major pathway that is required for induction of hepcidin expression in response to increasing levels of iron. Strong links between iron homeostasis, BMP signaling, inflammation and atherosclerosis have been established in both mechanistic and human studies. This review summarizes the current understanding of the role of iron homeostasis and hepcidin in the development of atherosclerosis and discusses the BMP-hepcidin-ferroportin axis as a novel therapeutic target for the treatment of cardiovascular disease.

MicroRNAs are Necessary for BMP-7-induced Dendritic Growth in Cultured Rat Sympathetic Neurons

Neuronal connectivity is dependent on size and shape of the dendritic arbor. However, mechanisms controlling dendritic arborization, especially in the peripheral nervous system, are not completely understood. Previous studies have shown that bone morphogenetic proteins (BMPs) are important initiators of dendritic growth in peripheral neurons. In this study, we examined the hypothesis that post-transcriptional regulation mediated by microRNAs (miRNAs) is necessary for BMP-7-induced dendritic growth in these neurons. To examine the role of miRNAs in BMP-7-induced dendritic growth, microarray analyses was used to profile miRNA expression in cultured sympathetic neurons from the superior cervical ganglia of embryonic day 21 rat pups at 6 and 24 h after treatment with BMP-7 (50 ng/mL). Our data showed that BMP-7 significantly regulated the expression of 43 of the 762 miRNAs. Of the 43 miRNAs, 22 showed robust gene expression; 14 were upregulated by BMP-7 and 8 were downregulated by BMP-7. The expression profile for miR-335, miR-664-1*, miR-21, and miR-23b was confirmed using qPCR analyses. Functional studies using morphometric analyses of dendritic growth in cultured sympathetic neurons transfected with miRNA mimics and inhibitors indicated that miR-664-1*, miR-23b, and miR-21 regulated early stages of BMP-7-induced dendritic growth. In summary, our data provide evidence for miRNA-mediated post-transcriptional regulation as important downstream component of BMP-7 signaling during early stages of dendritic growth in sympathetic neurons.

BMP4 patterns Smad activity and generates stereotyped cell fate organization in spinal organoids

Bone morphogenetic proteins (BMPs) are secreted regulators of cell fate in several developing tissues. In the embryonic spinal cord, they control the emergence of the neural crest, roof plate and distinct subsets of dorsal interneurons. Although a gradient of BMP activity has been proposed to determine cell type identity in vivo, whether this is sufficient for pattern formation in vitro is unclear. Here, we demonstrate that exposure to BMP4 initiates distinct spatial dynamics of BMP signalling within the self-emerging epithelia of both mouse and human pluripotent stem cell-derived spinal organoids. The pattern of BMP signalling results in the stereotyped spatial arrangement of dorsal neural tube cell types, and concentration, timing and duration of BMP4 exposure modulate these patterns. Moreover, differences in the duration of competence time-windows between mouse and human account for the species-specific tempo of neural differentiation. Together, this study describes efficient methods for generating patterned subsets of dorsal interneurons in spinal organoids and supports the conclusion that graded BMP activity orchestrates the spatial organization of the dorsal neural tube cellular diversity in mouse and human.

Effects of recombinant human bone morphogenetic protein-2 compared to other biomaterials in the treatment of intrabony defects in periodontitis patients: A systematic review

Background:

Bone morphogenetic proteins have a powerful osteoinductive capacity and have been used as a new adjunct to graft materials for bone regeneration. The objectives of this systematic review are to assess the amount of radiographic bone fill, clinical attachment level (CAL) gain, and reduction in pocket depth (PD) in patients with intrabony defects in periodontitis patients following the use of recombinant human bone morphogenetic protein-2 (rhBMP-2).

Materials and Methods:

Electronic bibliographic databases search of Medline, Science Direct, and Google Scholar was made from January 1980 to December 2017. Studies using rhBMP-2 to treat periodontal intrabony defects of the maxillary or mandibular region with follow-up period of at least 6 months were searched. Two reviewers performed the systematic review using the PRISMA Statement for reporting and the Cochrane risk-of-bias tool was used for quality assessment.

Results:

It was found that rhBMP-2 showed statistically significant results with respect to radiographic defect resolution, CAL, and PD reduction at 9 months compared to open-flap debridement but showed statistically significant results only with respect to radiographic bone fill when compared with platelet-rich fibrin at 6 months.

Conclusion:

The rhBMP-2 may provide a promising alternative to traditional grafting procedures therapy that can enhance periodontal regeneration in patients having intrabony defects. Due to limited human studies, it can be concluded that no definitive evidence exists to ascertain the effectiveness of rhBMP-2 in the treatment of intrabony defects in periodontal diseases.

Postulated release profile of recombinant human bone morphogenetic protein-2 (rhBMP-2) from demineralized dentin matrix

Demineralized dentin matrix (DDM) has been used as a recombinant human bone morphogenetic protein-2 (rhBMP-2) carrier in many clinical trials. To optimize the clinical safety and efficacy of rhBMP-2 with DDM, efforts have been made to improve the delivery of rhBMP-2 by 1) lowering the administered dose, 2) localizing the protein, and 3) prolonging its retention time at the action site as well as the bone forming capacity of the carrier itself. The release profile of rhBMP-2 that is associated with endogenous BMP in dentin has been postulated according to the type of incorporation, which is attributed to the loosened interfibrillar space and nanoporous dentinal tubule pores. Physically adsorbed and modified, physically entrapped rhBMP-2 is sequentially released from the DDM surface during the early stage of implantation. As DDM degradation progresses, the loosened interfibrillar space and enlarged dentinal tubules release the entrapped rhBMP-2. Finally, the endogenous BMP in dentin is released with osteoclastic dentin resorption. According to the postulated release profile, DDM can therefore be used in a controlled manner as a sequential delivery scaffold for rhBMP-2, thus sustaining the rhBMP-2 concentration for a prolonged period due to localization. In addition, we attempted to determine how to lower the rhBMP-2 concentration to 0.2 mg/mL, which is lower than the approved 1.5 mg/mL.

[Stimulation of fracture healing by growth factors and cell-based technologies]

Bone has the special capability to completely regenerate after trauma and to re-establish its original geometry and biomechanical stability corresponding to the pretrauma conditions. Nevertheless, in daily clinical practice impaired fracture healing and nonunions are regular complications as a result of inadequate mechanical stability and/or insufficient biological processes around the fracture region. Since the beginning of the millennium, intensive research on the physiological processes in bone healing as well as the production and clinical administration of growth factors have enabled the possibility to improve the local biological processes during fracture healing by osteoinduction. Although the initial clinical results, particularly of bone morphogenetic proteins, in fracture healing were promising, growth factors did not become established for unrestricted use in the clinical application. Currently, additional growth factors are being investigated with respect to the potential supportive and osteoinductive characteristics for enhancement of fracture healing and possible clinical applications. Furthermore, the development of cell-based technologies is another promising approach to positively stimulate fracture healing. In addition to the gold standard of autologous bone grafting, harvesting of mesenchymal stroma cells by aspiration has gained in importance in recent years. Allogeneic bone cell transplantation procedures and in particular gene therapy are promising new strategies for the treatment of disorders of fracture healing. This review gives an overview of present and future possibilities for modulation of fracture healing by growth factors and cell-based technologies.

Noninstrumented Lumbar Fusion with Bone Morphogenetic Proteins for Spinal Stenosis with Spondylolisthesis in the Elderly

OBJECTIVE

This study examined the use of noninstrumented posterolateral lumbar fusion with bone morphogenetic protein (BMP) and compared its effectiveness with that of instrumented fusion for the treatment of lumbar spinal stenosis (LSS) with spondylolisthesis in elderly patients.

METHODS

This study was a retrospective review of 93 patients treated in a single-surgeon neurosurgical private practice over a 15-year period. Fifty-nine patients over the age of 65 who underwent noninstrumented posterolateral fusion with rhBMP-2 (Infuse) for LSS with spondylolisthesis were compared with 34 patients who underwent instrumented fusion without rhBMP-2. Outcomes in terms of reoperation rate, pain improvement, Oswestry Disability Index (ODI) score, and number of extra follow-up visits due to persistent problems were characterized by the use of t tests and χ² tests.

RESULTS

The reoperation rate in the noninstrumented rhBMP-2 fusion group was significantly lower than in the instrumented fusion group (17.6% vs. 3.4%, P = 0.048). The mean pain improvement was significantly higher in the noninstrumented rhBMP-2 group at 3 months (8.1 vs. 6.0, P < 0.001, 95% confidence interval [CI] 1.2 to 3.0) and at 1 year (7.25 vs. 5.6, P = 0.030, 95% CI 0.3 to 3.1). The ODI score improvement was significantly higher in the noninstrumented rhBMP-2 group (51 vs. 42.8, P < 0.001, 95% CI 4.7 to 11.6). The mean number of additional follow-up visits per patient was significantly lower in the noninstrumented rhBMP-2 group (0.068 vs. 1.23, P < 0.001, 95% CI 0.59 to 1.75).

CONCLUSION

Noninstrumented posterolateral lumbar fusion with rhBMP-2 in elderly patients with LSS and spondylolisthesis is a viable alternative to instrumented fusion based on clinical outcomes measured in this study.

The role of heparin, heparanase and heparan sulfates in hepcidin regulation

Hepcidin is considered the major regulator of systemic iron homeostasis in human and mice, and its expression in the liver is mainly regulated at a transcriptional level. Central to its regulation are the bone morphogenetic proteins, particularly BMP6, that are heparin binding proteins. Heparin was found to inhibit hepcidin expression and BMP6 activity in hepatic cell lines and in mice, suggesting that endogenous heparan sulfates are involved in the pathway of hepcidin expression. This was confirmed by the study of cells and mice overexpressing heparanase, the enzyme that hydrolyzes heparan sulfates, and by cellular models with altered heparan sulfates. The evidences supporting the role of heparan sulfate in hepcidin expression are summarized in this chapter and open the way for new understanding in hepcidin expression and its control in pathological condition.

Common Genetic Variants on Bone Morphogenetic Protein Receptor Type IB (BMPR1B) Gene Are Predictive for Carotid Intima-Media Thickness

BACKGROUND

Bone morphogenetic proteins (BMP) 2 and 4 are implicated in the development of atherosclerosis. However, the relationships between the proteins, their main receptors and carotid intima-media thickness (cIMT), a predictive preclinical phenotype of atherosclerosis, have not been established. Methods and Results: We screened and validated the relationships of single-nucleotide polymorphisms (SNPs) on BMP2, BMP4, BMPR1A, BMPR1B, and BMPR2 with thicker cIMT by 2 independent case-control studies that used different subject selection methods. Among 200 screened SNPs, 12 on BMPR1B were regarded as candidate genetic markers (P-value <5.0×10^-4). After combining the discovery and validation studies and adjusting for traditional cardiovascular risk factors, rs4456963*G, rs4235438*T, rs2522530*T, and rs3796433*C showed significant higher odds ratios (ORs) of having thicker cIMT (adjusted ORs: 1.50-1.56; all P-values <2.5×10^-4). Multivariate analyses showed that rs4456963 and rs3796433 were significantly independent determinants of cIMT thickening. The corresponding multivariate-adjusted ORs for rs4456963*G and rs3796433*C alleles were 1.50 (95% confidence interval (CI): 1.22-1.84) and 1.50 (95% CI: 1.23-1.82), respectively. Interaction between rs4456963 and rs3796433 was evident by the significantly higher OR (8.16, 95% CI: 3.12-21.3) for subjects with the GG-CC genotype. The rs4456963*G and rs3796433*C showed positively linear trends with severity of carotid atherosclerosis.

CONCLUSIONS

We identified 2 SNPs on BMPR1B showing significantly independent correlations with thicker cIMT. The study provides invaluable evidence supporting that BMPR1B is closely related to carotid atherosclerosis and a potential target for the development of therapeutic agents for atherosclerotic disease.

rhBMP in lumber fusion for lumbar spondylolisthesis: A systematic review and meta-analysis

PURPOSE

To compare the efficacy and safety of recombinant human bone morphogenetic protein (rhBMP) and iliac crest autograft in the fusion treatment of lumbar spondylolisthesis.

METHODS

The studies using randomized controlled trials to compare the rhBMP with iliac crest autograft in the treatment of lumbar spondylolisthesis were retrieved from Embase, Pubmed, ProQuest dissertations & theses (PQDT), China national knowledge infrastructure (CNKI), Chinese Biomedical Database, Wanfang Data, Cochrane Library (from March 1998 to March 2018). Postoperative fusion rate, clinical success rate, postoperative intervertebral height, complications, operation time, blood loss and duration of hospitalization were chosen as the outcome indicators. Methodological quality of the trials was critically assessed, and relevant data were extracted. Statistical software Revman 5.3 was used for data-analysis.

RESULTS

Eleven articles were included in the meta-analysis. The results showed that, comparing the efficacy of rhBMP with iliac crest autograft, statistical significance was found in the 24-month fusion rate post operation [95% CI (1.38, 24.70), p = 0.02] and operation time [95% CI (-14.22, -2.08), p = 0.008]. There is not sufficient evidence for statistical differences in the remaining indicators.

CONCLUSION

The current literature shows rhBMP is a safe and effective grafting material in the treatment of lumbar spondylolisthesis. Further evidence is dependent on the emergence of more randomized controlled trials with higher quality and larger sample sizes in the future.

Reduced levels of Coco in sera of multiple sclerosis patients: A potential role in neuro-regeneration failure

Demyelination, axonal loss and failure of tissue repair characterize MS lesions. Bone morphogenetic proteins (BMPs) signaling is associated with remyelination failure. Coco is one of the BMP antagonists. We found reduced Coco serum levels in relapsing-remitting MS (RR-MS) and primary progressive MS (PP-MS) patients compared to matched healthy controls (HC) and patients with rheumatoid arthritis. Exposure of P19 cells, in the presence of retinoic acid, BMP-2, or BMP-4 to Coco, at average sera level of MS patients failed to induce neuronal phenotype, in contrast to the average sera level of HC. Coco may be a player in the BMP dysregulation and the tissue repair failure in MS.

Cellular signaling in pseudoxanthoma elasticum: an update

Pseudoxanthoma elasticum is an autosomal recessive genodermatosis with variable expression, due to mutations in the ABCC6 or ENPP1 gene. It is characterized by elastic fiber mineralization and fragmentation, resulting in skin, eye and cardiovascular symptoms. Significant advances have been made in the last 20 years with respect to the phenotypic characterization and pathophysiological mechanisms leading to elastic fiber mineralization. Nonetheless, the substrates of the ABCC6 transporter - the main cause of PXE - remain currently unknown. Though the precise mechanisms linking the ABCC6 transporter to mineralization of the extracellular matrix are unclear, several studies have looked into the cellular consequences of ABCC6 deficiency in PXE patients and/or animal models. In this paper, we compile the evidence on cellular signaling in PXE, which seems to revolve mainly around TGF-βs, BMPs and inorganic pyrophosphate signaling cascades. Where conflicting results or fragmented data are present, we address these with novel signaling data. This way, we aim to better understand the up- and down-stream signaling of TGF-βs and BMPs in PXE and we demonstrate that ANKH deficiency can be an additional mechanism contributing to decreased serum PPi levels in PXE patients.

Activin A/BMP2 Chimera (AB204) Exhibits Better Spinal Bone Fusion Properties than rhBMP2

Objective

To compare the spinal bone fusion properties of activin A/BMP2 chimera (AB204) with recombinant human bone morphogenetic protein (rhBMP2) using a rat posterolateral spinal fusion model.

Methods

The study was designed to compare the effects and property at different dosages of AB204 and rhBMP2 on spinal bone fusion. Sixty-one male Sprague-Dawley rats underwent posterolateral lumbar spinal fusion using one of nine treatments during the study, that is, sham; osteon only; 3.0 μg, 6.0 μg, or 10.0 μg of rhBMP2 with osteon; and 1.0 μg, 3.0 μg, 6.0 μg, or 10.0 μg of AB204 with osteon. The effects and property on spinal bone fusion was calculated at 4 and 8 weeks after treatment using the scores of physical palpation, simple radiograph, micro-computed tomography, and immunohistochemistry.

Results

Bone fusion scores were significantly higher for 10.0 μg AB204 and 10.0 μg rhBMP2 than for osteon only or 1.0 μg AB204. AB204 exhibited more prolonged osteoblastic activity than rhBMP2. Bone fusion properties of AB204 were similar with the properties of rhBMP2 at doses of 6.0 and 10.0 μg, but, the properties of AB204 at doses of 3.0 μg exhibited better than the properties of rhBMP2 at doses of 3.0 μg.

Conclusion

AB204 chimeras could to be more potent for treating spinal bone fusion than rhBMP2 substitutes with increased osteoblastic activity for over a longer period.

Bone morphogenetic proteins for articular cartilage regeneration

Degeneration of articular cartilage (AC) tissue is the most common cause of osteoarthritis (OA) and rheumatoid arthritis. Bone morphogenetic proteins (BMPs) play important roles in bone and cartilage formation. This article reviews the experimental and clinical applications of BMPs in cartilage regeneration. Experimental evidence indicates that BMPs play an important role in protection against cartilage damage caused by inflammation or trauma, by binding to different receptor combinations and, consequently, activating different intracellular signaling pathways. Loss of function of BMP-related receptors contributes to the decreased intrinsic repair capacity of damaged cartilage and, thus, the multifunctional effects of BMPs make them attractive tools for the treatment of cartilage damage in patients with degenerative diseases. However, the development of BMP therapy as a treatment modality for cartilage regeneration has been hampered by certain factors, such as the eligibility of participants in clinical trials, financial support, drug delivery carrier safety, availabilities of effective scaffolds, appropriate selection of optimal dose and timing of administration, and side effects. Further research is needed to overcome these issues for future routine clinical applications. Research and development leading to the successful application of BMPs can initiate a new era in the treatment of cartilage degenerative diseases like OA.

Increased kielin/chordin-like protein levels are associated with the severity of heart failure

BACKGROUND

Previous studies demonstrated that the transforming growth factor (TGF) β superfamily, including TGF-βs and bone morphogenetic proteins (BMPs), plays important roles in cardiovascular diseases. The kielin/chordin-like protein (KCP) is a secreted protein that regulates the expression and function of TGF-βs and BMPs. However, the role of KCP during heart failure (HF) remains unknown. The present study aimed to investigate the cardiac expression of KCP in human failing hearts.

METHODS

The human failing heart samples from patients with dilated cardiomyopathy (DCM, n = 12) and ischemic cardiomyopathy (ICM, n = 12) were collected, and normal heart (n = 8) samples from unmatched donors were collected as controls. Collagen volume, KCP levels, and mRNA levels of several BMPs in left ventricles (LV) of all hearts were measured.

RESULTS

The KCP levels were significantly higher in human failing hearts than in normal hearts. KCP levels were positively associated with hypertrophy markers, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC). In addition, KCP levels were also positively associated with left ventricular end-diastolic dimension (LVEDD), collagen Iα and collagen IIIα expression but were negatively associated with left ventricular ejection fraction (LVEF). Furthermore, increased TGF-β1, BMP2/4/6/10 and reduced BMP7 levels were observed, and positive correlations between KCP and TGF-β1 and negative correlation between KCP and BMP2/7 were found, but not for BMP4/6/10.

CONCLUSIONS

KCP was closely associated with heart failure. The regulation of BMP2/7 and TGF-β1 expression may be the possible mechanisms.