Presence of single nucleotide polymorphisms in transforming growth factor β and insulin-like growth factor 1 in class II malocclusions due to retrognathic mandible

AIM

The aim of this study was to evaluate specific single nucleotide polymorphisms (SNP) of transforming growth factor-beta (TGF-β) (rs1800469) and insulin-like growth factor-1 (IGF-1) (rs17032362) genes in Class II individuals with a normal maxilla and retrognathic (short) mandible.

Endochondral Bone Tissue Engineering Using Human Induced Pluripotent Stem Cells

There has been great interest in the use of induced pluripotent stem cells (iPSCs) in bone regenerative strategies for bone defects. In the present study, we investigated whether the implantation of chondrogenically differentiated iPSC-derived mesenchymal stem cells (iMSCs) could lead to the successful regeneration of bone defects in nude mice. Two clones of human iPSCs (201B7 and 454E2) were used. After the generation of iMSCs, chondrogenic differentiation was achieved using a three-dimensional pellet culture. Then, a 2-mm defect was created in the radius of nude mice and chondrogenically differentiated iMSC pellets were placed in the defect. Micro-computed tomography (μ-CT) imaging analysis was performed 8 weeks after transplantation to assess bone regeneration. Eleven out of 11 (100%) radii in the 201B7 cell-derived-pellet transplantation group and 7 out of 10 (70%) radii in the 454E2 cell-derived-pellet transplantation group showed bone union. On the other hand, only 2 out of 11 radii (18%) in the control group showed bone union. Therefore, the bone union rates in the experimental groups were significantly higher than that in the control group (p < 0.05). Histological analysis 2 weeks post-implantation in the experimental groups revealed hypertrophic chondrocytes within grafted iMSC pellets, and the formation of woven bone around them; this hypertrophic chondrocyte transitioning to the newly formed bone suggests that the cartilaginous template can trigger the process of endochondral bone ossification (ECO). Four weeks post-implantation, the cartilage template was reduced in size; newly formed woven bone predominated at the defect site. New vessels were surrounded by a matrix of woven bone and the hypertrophic chondrocytes transitioning to the newly formed bone indicated the progression of ECO. Eight weeks post-implantation, the pellets were completely resorbed and replaced by bone; complete bone union was overall observed. Dense mature bone developed with evidence of lamellar-like bone formation. Collectively, our results suggest that iMSC-based cartilage grafts recapitulating the morphogenetic process of ECO in the context of embryonic skeletogenesis are a novel and promising strategy for the repair of large bone defects.

Growth factor profile in calcified cartilage from the metaphysis of a calf costochondral junction, the site of initial bone formation

Endochondral bone formation is orchestrated by growth factors produced by chondrocytes and deposited in the cartilage matrix. Whilst some of these factors have been identified, the complete list and their relationship remains unknown. In the present study, the growth factors were isolated from non-calcified and calcified cartilage of costochondral junctions. Cartilage dissected from the ribs of 6-20-week-old calves was purchased from a local butcher within 24 h of the death of the animal. The isolation involved hyaluronidase digestion, guanidinium hydrochloride (GuHCl) extraction, HCl decalcification and GuHCl extraction of the decalcified matrix. Growth factors were purified by heparin chromatography and their quantities were estimated using ELISA. Decalcified cartilage was also used for protein sequence analysis (data are available via ProteomeXchange; ID, PXD021781). Bone morphogenetic protein-7 (BMP-7), growth/differentiation factor-5 (GDF-5) and NEL-like protein-1 (NELL-1), all known growth factors that stimulate bone formation, quantitatively accounted for the majority of the material obtained in all steps of isolation. Thus, cartilage serves as a store for growth factors. During initial bone formation septoclasts release osteoclastogenesis-stimulating factors deposited in non-calcified cartilage. Osteoclasts dissolve calcified cartilage and transport the released factors required for the stimulation of osteoprogenitor cells to deposit osteoid. High concentrations of BMP-7, GDF-5 and NELL-1 at the site of initial bone formation may suggest that their synergistic action favours osteogenesis.

Scaffold-Mediated Gene Delivery for Osteochondral Repair

Osteochondral defects involve both the articular cartilage and the underlying subchondral bone. If left untreated, they may lead to osteoarthritis. Advanced biomaterial-guided delivery of gene vectors has recently emerged as an attractive therapeutic concept for osteochondral repair. The goal of this review is to provide an overview of the variety of biomaterials employed as nonviral or viral gene carriers for osteochondral repair approaches both in vitro and in vivo, including hydrogels, solid scaffolds, and hybrid materials. The data show that a site-specific delivery of therapeutic gene vectors in the context of acellular or cellular strategies allows for a spatial and temporal control of osteochondral neotissue composition in vitro. In vivo, implantation of acellular hydrogels loaded with nonviral or viral vectors has been reported to significantly improve osteochondral repair in translational defect models. These advances support the concept of scaffold-mediated gene delivery for osteochondral repair.

Identification of Candidate Genetic Markers and a Novel 4-genes Diagnostic Model in Osteoarthritis through Integrating Multiple Microarray Data

BACKGROUND

Osteoarthritis (OA) is a joint disease that leads to a high disability rate and a low quality of life. With the development of modern molecular biology techniques, some key genes and diagnostic markers have been reported. However, the etiology and pathogenesis of OA are still unknown.

OBJECTIVE

To develop a gene signature in OA.

METHOD

In this study, five microarray data sets were integrated to conduct a comprehensive network and pathway analysis of the biological functions of OA related genes, which can provide valuable information and further explore the etiology and pathogenesis of OA.

RESULTS AND DISCUSSION

Differential expression analysis identified 180 genes with significantly expressed expression in OA. Functional enrichment analysis showed that the up-regulated genes were associated with rheumatoid arthritis (p < 0.01). Down-regulated genes regulate the biological processes of negative regulation of kinase activity and some signaling pathways such as MAPK signaling pathway (p < 0.001) and IL-17 signaling pathway (p < 0.001). In addition, the OA specific protein-protein interaction (PPI) network was constructed based on the differentially expressed genes. The analysis of network topological attributes showed that differentially upregulated VEGFA, MYC, ATF3 and JUN genes were hub genes of the network, which may influence the occurrence and development of OA through regulating cell cycle or apoptosis, and were potential biomarkers of OA. Finally, the support vector machine (SVM) method was used to establish the diagnosis model of OA, which not only had excellent predictive power in internal and external data sets (AUC > 0.9), but also had high predictive performance in different chip platforms (AUC > 0.9) and also had effective ability in blood samples (AUC > 0.8).

CONCLUSION

The 4-genes diagnostic model may be of great help to the early diagnosis and prediction of OA.

Creation of different bioluminescence resonance energy transfer based biosensors with high affinity to VEGF

In age-related macular degeneration (AMD) or diabetic retinopathy (DR), hypoxia and inflammatory processes lead to an upregulation of the vascular endothelial growth factor (VEGF) expression and thereby to pathological neovascularisation with incorrectly formed vessels prone to damage, thus increasing the vascular permeability and the risk of bleeding and oedema in the retina. State of the art treatment is the repeated intraocular injection of anti-VEGF molecules. For developing improved individualized treatment approaches, a minimally invasive, repeatable method for in vivo quantification of VEGF in the eye is necessary. Therefore, we designed single molecule eBRET2 VEGF biosensors by directly fusing a Renilla luciferase mutant (Rluc8) N-terminal and a green fluorescent protein (GFP2) C-terminal to a VEGF binding domain. In total, 10 different VEGF biosensors (Re01- Re10) were generated based on either single domains or full length of VEGF receptor 1 or 2 extracellular regions as VEGF binding domains. Full length expression of the biosensors in HEK293-T cells was verified via Western Blot employing an anti-Rluc8-IgG. Expression of alternative splice variants was eliminated through the deletion of the donor splice site by introduction of a silent point mutation. In all ten biosensors the energy transfer from the Rluc8 to the GFP2 occurs and generates a measurable eBRET2 ratio. Four biosensors show a relevant change of the BRET ratio (ΔBR) after VEGF binding. Furthermore, each biosensor shows a unique detection range for VEGF quantification and especially Re06 and Re07 have a high sensitivity in the range of in vivo VEGF concentrations in the eye, previously measured by invasive methods. In conclusion, we generated several eBRET2 biosensors that are suitable for VEGF quantification in vitro and could identify two eBRET2 biosensors, which may be suitable for non-invasive in vivo VEGF quantification with an implantable device.

miR-17-5p Regulates Heterotopic Ossification by Targeting ANKH in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized with heterotopic ossification of the axis joints ligaments, resulting in joint disability. MicroRNAs (miRNAs) are regulators of mRNAs that play a crucial role in the AS pathological process. Here, we showed that the level of miR-17-5p was significantly higher in fibroblasts and ligament tissues from AS patients as compared to the non-AS individuals. Knockdown of the miR-17-5p from the fibroblasts derived from AS patients exhibited decreased osteogenic differentiation and ossification. On the other hand, AS patient-derived fibroblasts overexpressing miR-17-5p displayed the increased osteogenesis. Furthermore, inhibition of miR-17-5p ameliorated osteophyte formation, and the sacroiliitis phenotype in AS rats received emulsified collagen. Mechanistically, miR-17-5p regulated osteogenic differentiation by targeting the 3ʹ UTR of ankylosis protein homolog (ANKH). Also, downregulation of miR-17-5p slowed AS progression through regulation of cytokines, such as dickkopf-1 (DKK1) and vascular endothelial growth factor (VEGF). In conclusion, our findings reveal a role of the miR-17-5p-ANKH axis in the regulation of heterotopic ossification, which is essential for therapeutic intervention in heterotopic ossification in AS.

Ginsenoside Rb1 prevents steroid‑induced avascular necrosis of the femoral head through the bone morphogenetic protein‑2 and vascular endothelial growth factor pathway

At present, the molecular mechanism underlying the protective effect of Ginsenoside Rb1 remains unclear. The present study was designed to investigate whether Ginsenoside Rb1 weakened the steroid-induced avascular necrosis of the femoral head (SANFH) and to explore the possible mechanisms of the above effects. As a result, it was revealed that Ginsenoside Rb1 was protective against steroid-induced avascular necrosis and inhibited serum osteocalcin in a rat model of SANFH. Ginsenoside Rb1 reduced inflammation, oxidative stress and bone cell apoptosis in a rat model of SANFH. Furthermore, Ginsenoside Rb1 attenuated trabecula parameters, total cholesterol and low density lipoprotein/high density lipoprotein in SANFH rat. Additionally, Ginsenoside Rb1 significantly reversed alkaline phosphatase and osteocalcin activities, vascular endothelial growth factor (VEGF) receptor, VEGF, Runt related transcription factor 2 (Runx2) and bone morphogenetic protein (BMP)-2 protein expression in SANFH rat. Collectively, the present study demonstrated that Ginsenoside Rb1 attenuated SANFH through the VEGF/RUNX2/BMP-2 signaling pathway.

Expression analysis of the osteoarthritis genetic susceptibility mapping to the matrix Gla protein gene MGP

BACKGROUND

Osteoarthritis (OA) is a common disease of older individuals that impacts detrimentally on the quality and the length of life. It is characterised by the painful loss of articular cartilage and is polygenic and multifactorial. Genome-wide association scans have highlighted over 90 osteoarthritis genetic signals, some of which reside within or close to highly plausible candidate genes. An example is an association to polymorphisms within and adjacent to the matrix Gla protein gene MGP. We set out to undertake a functional study of this gene.

METHODS

Nucleic acid was extracted from cartilage, infrapatellar fat pad, synovium, trabecular bone, trapezium and peripheral whole blood from OA patients and also from mesenchymal stem cells (MSCs) subjected to chondrogenesis. Expression of MGP was measured by quantitative PCR (qPCR), RNA-sequencing and allelic expression imbalance (AEI) analysis. Matrix Gla protein was depleted in chondrocytes by knocking down MGP expression using RNA interference (RNAi) and the effect on a range of genes assessed by qPCR.

RESULTS

MGP is expressed in joint tissues, blood and chondrocytes cultured from MSCs. There is a higher expression in diseased versus non-diseased cartilage. Polymorphisms that are associated with OA also correlate with the expression of MGP, with the OA risk-conferring allele showing significantly reduced expression in cartilage, fat pad and synovium but increased expression in blood. Depletion of Matrix Gla protein had a significant effect on the majority of genes tested, with an increased expression of catabolic genes that encode enzymes that degrade cartilage.

CONCLUSIONS

MGP expression is subject to cis-acting regulators that correlate with the OA association signal. These are active in a range of joint tissues but have effects which are particularly strong in cartilage. An opposite effect is observed in blood, highlighting the context-specific nature of the regulation of this gene's expression. Recapitulation of the genetic deficit in cartilage chondrocytes is pro-catabolic.

Postnatal expression of chondrogenic and osteogenic regulatory factor mRNA in the rat condylar cartilage

OBJECTIVES

The condylar cartilage is a key site of growth and development of the mandible. The aim of this research was to determine the mRNA expression levels of a number of chondrogenic and osteogenic regulatory factors in the condylar cartilage of the postnatal rat.

MATERIALS AND METHODS

Condyles were extracted from 40 rats aged 4, 10, 21 or 90 days with 10 rats assigned to each age group. The condyles from one rat from each age group was fixed and decalcified in 10% EDTA for histology. Using cryogenic grinding combined with QIAzol reagent total RNA was purified from pooled samples collected for each age group. Each pool contained six condyles (N = 3). mRNA expression levels for 28 genes were determined using qPCR.

RESULTS

Histological analysis revealed distinct morphological differences in the condyle tissue of the 4, 10, 21 and 90 day old postnatal rats. Expression of all examined genes was detected. High levels of mRNA for Alpl, Bglap, Col1a1, Col2a1, Runx2, Sox9 and Sp7 but not Msx1 were detected. Fgf1 and Fgf2 were expressed at a similar level. No significant difference (defined as ± fold-regulation > 2 and P < 0.05) in the gene mRNA expression levels was found when days 10, 21 or 90 were compared to day 4.

CONCLUSIONS

Apparent morphological changes of the rat condylar cartilage are not reflected in a change in the expression levels of the chondrogenic and osteogenic regulatory factor mRNA investigated in this study.

Osmolyte Type and the Osmolarity Level Affect Chondrogenesis of Mesenchymal Stem Cells

The inductive effects of increased osmolarity on chondrogenesis are well approved. However, the effects of the osmolyte agent invoked to induce hyperosmolarity are largely neglected. Herein, we scrutinized how hyperosmotic conditions acquired by addition of different osmolytes would impact chondrogenesis. We briefly assessed whether such conditions would differentially affect hypertrophy and angiogenesis during MSC chondrogenesis. Chondrogenic and hypertrophic marker expression along with VEGF secretion during adipose-derived (AD)-MSC chondrogenesis under three osmolarity levels (350, 450, and 550 mOsm) using three different osmolytes (NaCl, sorbitol, and PEG) were assessed. MTT assay, qRT-PCR, immunocytochemistry, Alcian Blue staining, ELISA, and ALP assays proved osmolyte-type dependent effects of hyperosmolarity on chondrogenesis, hypertrophy, and angiogenesis. At same osmolarity level, PEG had least cytotoxic/cytostatic effect and most prohibitive effects on angiogenesis. As expected, all hyperosmolar conditions led to enhanced chondrogenesis with slightly varying degrees. PEG and sorbitol had higher chondro-promotive and hypertrophy-suppressive effects compared to NaCl, while NaCl had exacerbated hypertrophy. We observed that TonEBP was involved in osmoadaptation of all treatments in varying degrees. Of importance, we highlighted differential effects of hyperosmolarity obtained by different osmolytes on the efficacy of chondrogenesis and more remarkably on the induction/suppression of cartilage pathologic markers. Our study underlies the need for a more vigilant exploitation of physicobiochemical inducers in order to maximize chondrogenesis while restraining unwanted hypertrophy and angiogenesis.

Associations of the VEGF level, VEGF rs2010963 G/C gene polymorphism and ankylosing spondylitis risk in a Chinese Han population

To investigate the roles of the plasma vascular endothelial growth factor (VEGF) level and VEGF gene polymorphisms in ankylosing spondylitis (AS) susceptibility. The plasma VEGF level was measured using an enzyme-linked immunosorbent assay. The VEGF rs2010963 G/C gene polymorphism was analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Our data indicated that the average plasma VEGF concentration in the AS patients was markedly higher than in the controls. Stratification analysis indicated a significant correlation between an elevated plasma VEGF level in AS patients and sex, but not age, HLA-B27, C-reactive protein (CRP), or grade of the sacroiliac joint. We also found that VEGF rs2010963 G/C was associated with a decreased risk of AS. Significant differences were found between the VEGF rs2010963 G/C genotypes and elevated plasma level in AS patients when compared with the controls. However, we did not find a significant association between the plasma VEGF level and different rs2010963 G/C genotypes in the AS patients or controls. To sum up, serum VEGF levels are significantly associated with the inflammatory process of AS. This study suggests that VEGF is involved in the immunological or inflammatory process of AS.

Serum levels of Dkk-1, sclerostin and VEGF in patients with ankylosing spondylitis and their association with smoking, and clinical, inflammatory and radiographic parameters

OBJECTIVE

To evaluate serum Dickkopf-1 (Dkk-1), sclerostin and vascular endothelial growth factor (VEGF) levels in patients with ankylosing spondylitis (AS) compared to healthy controls as well as their association with smoking, and clinical, inflammatory and radiographic parameters.

METHODS

Serum samples for total Dkk-1, sclerostin and VEGF were obtained from 57 tumour necrosis factor (TNF) inhibitor naïve patients with AS and 34 sex-, age- and body mass index (BMI)-matched controls. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), modified Stroke AS Spine Score (mSASSS) and smoking status were assessed for each patient.

RESULTS

There was no significant difference in serum bone metabolism markers between AS patients and controls. Dkk-1 levels were significantly (P<0.05) higher in AS patients with elevated ESR and CRP and no syndesmophytes, and were significantly (P<0.001) correlated with sclerostin levels (r=0.592). VEGF levels were significantly (P<0.05) higher in AS patients with current and ever smoking, elevated ESR and CRP, and high BASDAI and BASFI, and were significantly (P<0.05) correlated with ESR (r=0.284), CRP (r=0.285), BASDAI (r=0.349) and BASFI (r=0.275). In multivariate regression analyses, high Dkk-1 levels were significantly (P≤0.001) associated with elevated ESR and CRP, no syndesmophytes and high sclerostin levels, and high VEGF levels significantly (P<0.05) with ever smoking, and elevated ESR and CRP.

CONCLUSION

In AS, serum Dkk-1 concentrations appear to be related not only to syndesmophyte formation but also to systemic inflammation. Furthermore, high VEGF levels may be associated with smoking exposure.

THE VEGF AND BMP-2 LEVELS IN PATIENTS WITH ANKYLOSING SPONDYLITIS AND THE RELATIONSHIP TO TREATMENT WITH TUMOUR NECROSIS FACTOR ALPHA INHIBITORS

Introduction: Ankylosing spondylitis (AS) is an inflammatory rheumatic disease characterized by the development of osteoproductive changes in the spine which could possibly result in ankylosis. Treatment with tumour necrosis factor alpha (TNFα) inhibitors has proved to be an important step forward in the treatment of this disease, but for the time being it is not clear whether it favourably influences radiographic progression of the disease. Vascular endothelial growth factor most probably plays a role in the development of osteoproductive changes and recently its predictive influence on radiographic progression has been demonstrated. Bone morphogenic protein 2 (BMP-2) participates in the regulation of bone proliferation and its increased serum level has been demonstrated in patients with advanced AS and correlated with the degree of radiographic changes. Aim: The study aims to evaluate the VEGF and BMP-2 levels in patients with ankylosing spondylitis and how these levels relate to the concurrent treatment with TNFα inhibitors. Methods: Sera were evaluated from patients at the Rheumatologic Clinic of the Hradec Králové Faculty Hospital who fulfilled the modified New York Criteria for AS (n = 55). In these patients, the parameters of the activity of the disease (BASDAI = Bath Ankylosing Spondylitis Disease Activity Index, CRP = C-reactive protein) and the concurrent therapy (TNFα inhibitors, n = 21, vs. non-anti TNFα, n = 34) were recorded. The levels of VEGF and BMP-2 were analyzed using the ELISA method. Results: In patients treated with TNFα inhibitors, a significantly lower VEGF level was found when compared to untreated patients (140.3 (109.4; 262.2) vs. 261 (172.4; 396.6) pg/ml; p = 0.02). No difference was found between BMP-2 levels in both groups (treated vs. untreated patients) (254.8 (2301; 267.3) vs. 261.1 (248.6; 273.5) pg/ml; p = 0.24). A correlation analysis did not reveal any relationship between VEG F and BMP-2 (r = 0.057; p = 0.68). Serum levels of VEGF correlated with serum levels of CRP (r = 0.56; p = 0.00001) and the BASDAI value (r = 0.33; p = 0.015). Conclusion: Significantly lower VEGF levels were found in patients treated with TNFα inhibitors versus the untreated patients. These findings are in harmony with some hitherto published analyses and may give evidence of a favourable effect of TNFα inhibitors on radiographic progression. Neither influence on the BMP-2 level by treatment with TNFα inhibitors nor correlation with VEGF levels was demonstrated.

Circulating periostin levels in patients with AS: association with clinical and radiographic variables, inflammatory markers and molecules involved in bone formation

OBJECTIVE

The aim of this study was to evaluate serum periostin levels in patients with AS in comparison with healthy controls as well as their association with clinical, inflammatory and radiographic parameters and molecules involved in bone formation.

METHODS

Serum samples for periostin, total Dickkopf-1 (Dkk-1), sclerostin, VEGF and inflammatory markers were obtained from 65 TNF inhibitor-naive patients with AS. The BASDAI, BASFI, modified Stoke AS Spine Score and BASRI for the spine (BASRI-s) were assessed for each patient. Serum periostin levels were also measured in 36 sex-, age- and BMI-matched controls.

RESULTS

Serum periostin levels were significantly lower in AS patients compared with controls [234.4 pg/ml (s.e.m. 7.5) vs 291.4 (s.e.m. 8.3), respectively; P < 0.001]. Periostin levels were higher in AS patients with elevated CRP (P = 0.005), high BASDAI (P = 0.014) and low BASRI-s (P = 0.033) and were correlated with BMI (r = -0.304, P = 0.014), ESR (r = 0.395, P = 0.001), CRP (r = 0.413, P = 0.001), BASRI-s (r = -0.242, P = 0.047) and sclerostin (r = -0.280, P = 0.024). In multiple regression analysis, periostin levels were an independent variable of CRP (β = 0.160, P = 0.009) and sclerostin levels (β = -0.311, P = 0.012).

CONCLUSION

Our data suggest that periostin levels are low in patients with AS. Among AS patients, periostin levels are higher in those with higher disease activity, higher systemic inflammation and less extensive radiographic damage. Periostin is independently associated with CRP and sclerostin levels.

Gene therapy to stimulate angiogenesis to treat diffuse coronary artery disease

Cardiac gene therapy offers a strategy to treat diffuse coronary artery disease (CAD), a disorder with no therapeutic options. The use of genes to revascularize the ischemic myocardium has been the focus of two decades of preclinical research with a variety of angiogenic mediators, including vascular endothelial growth factor, fibroblast growth factor, hepatocyte growth factor, and others encoded by DNA plasmids or adenovirus vectors. The multifaceted challenge for developing efficient induction of collateral vessels in the ischemic heart requires a choice for route of delivery, dosing level, a relevant animal model, duration of treatment, and assessment of phenotype for efficacy. Overall, studies of gene therapy for ischemia in experimental models are very encouraging, with clear evidence of safety and efficacy, strongly supporting the concept that gene therapy to induce angiogenesis is a viable therapeutic approach for CAD. Clinical studies of cardiac gene therapy with angiogenic factors have added substantially to the evidence for efficacy, but definitive studies have not yet led to commercial approval. This review provides the general concepts for angiogenesis-based therapeutic approaches for diffuse CAD and summarizes the results from key studies in the field with recommendations for refinement to a successful product design and evaluation.

Aberrant and alternative splicing in skeletal system disease

The main function of skeletal system is to support the body and help movement. A variety of factors can lead to skeletal system disease, including age, exercise, and of course genetic makeup and expression. Pre-mRNA splicing plays a crucial role in gene expression, by creating multiple protein variants with different biological functions. The recent studies show that several skeletal system diseases are related to pre-mRNA splicing. This review focuses on the relationship between pre-mRNA splicing and skeletal system disease. On the one hand, splice site mutation that leads to aberrant splicing often causes genetic skeletal system disease, like COL1A1, SEDL and LRP5. On the other hand, alternative splicing without genomic mutation may generate some marker protein isoforms, for example, FN, VEGF and CD44. Therefore, understanding the relationship between pre-mRNA splicing and skeletal system disease will aid in uncovering the mechanism of disease and contribute to the future development of gene therapy.

Genetic expression of MMP-Matrix-mettalo-proteinases (MMP-1 and MMP-13) as a function of anterior mandibular repositioning appliance on the growth of mandibular condylar cartilage with and without administration of Insulin like growth factor (IGF-1) and Transforming growth factor-B (TGF-β)

OBJECTIVE

To determine if the mandibular condylar cartilage (MCC) will grow with and without mandibular anterior repositioning appliances with the administration of insulin-like growth factor (IGF-1) and transforming growth factor-β (TGF-β).

MATERIALS AND METHODS

Twenty-four growing New Zealand rabbits were divided into three groups: a group with saline injection in the temporomandibular joint, a group that received anterior positioning appliance, and a group that received injection of growth factors as well as mandibular repositioning appliance. Real-time reverse transcription polymerase chain reaction technique was used to study gene expression supported by histomorphometry.

RESULTS

Administration of growth factors along with mandibular repositioning appliances has induced 5.70-fold expression of matrix metalloproteinase-1 (MMP-1) (P < .0005) and 1.29-fold expression of MMP-13 (P < .0005). In contrast, administration of mandibular repositioning appliances only has induced 2.33-fold expression of MMP-1 (P < .0005) and 0.83-fold expression of MMP-13 (P < .0005). Histomorphometric analysis revealed increased proliferation of the condylar cartilage in the appliance and injection group as compared to the control group.

CONCLUSION

The administration of growth factors along with the use of mandibular advancement appliance has increased genetic expression of MMP-1 and MMP-13 supported by histomorphometric evidence indicating growth of condylar cartilage.

MSC and Tumors: Homing, Differentiation, and Secretion Influence Therapeutic Potential

: Mesenchymal stromal/stem cells (MSC) are adult multipotent progenitors with fibroblast-like morphology able to differentiate into adipocytic, osteogenic, chondrogenic, and myogenic lineages. Due to these properties, MSC have been studied and introduced as therapeutics in regenerative medicine. Preliminary studies have also shown a possible involvement of MSC as precursors of cellular elements within tumor microenvironments, in particular tumor-associated fibroblasts (TAF). Among a number of different possible origins, TAF may originate from a pool of circulating progenitors from bone marrow or adipose tissue-derived MSC. There is growing evidence to corroborate that cells immunophenotypically defined as MSC are able to reside as TAF influencing the tumor microenvironment in a potentially bi-phasic and obscure manner: either promoting or inhibiting growth depending on tumor context and MSC sources. Here we focus on relationships between the tumor microenvironment, cancer cells, and MSC, analyzing their diverse ability to influence neoplastic development. Associated activities include MSC homing driven by the secretion of various mediators, differentiation towards TAF phenotypes, and reciprocal interactions with the tumor cells. These are reviewed here with the aim of understanding the biological functions of MSC that can be exploited for innovative cancer therapy.

Vascular endothelial growth factor-delivery systems for cardiac repair: an overview

Since the discovery of the Vascular Endothelial Growth Factor (VEGF) and its leading role in the angiogenic process, this has been seen as a promising molecule for promoting neovascularization in the infarcted heart. However, even though several clinical trials were initiated, no therapeutic effects were observed, due in part to the short half life of this factor when administered directly to the tissue. In this context, drug delivery systems appear to offer a promising strategy to overcome limitations in clinical trials of VEGF.The aim of this paper is to review the principal drug delivery systems that have been developed to administer VEGF in cardiovascular disease. Studies published in the last 5 years are reviewed and the main features of these systems are explained. The tissue engineering concept is introduced as a therapeutic alternative that holds promise for the near future.

Strain tunes proteolytic degradation and diffusive transport in fibrin networks

Proteolytic degradation of fibrin, the major structural component in blood clots, is critical both during normal wound healing and in the treatment of ischemic stroke and myocardial infarction. Fibrin-containing clots experience substantial strain due to platelet contraction, fluid shear, and mechanical stress at the wound site. However, little is understood about how mechanical forces may influence fibrin dissolution. We used video microscopy to image strained fibrin clots as they were degraded by plasmin, a major fibrinolytic enzyme. Applied strain causes up to 10-fold reduction in the rate of fibrin degradation. Analysis of our data supports a quantitative model in which the decrease in fibrin proteolysis rates with strain stems from slower transport of plasmin into the clot. We performed fluorescence recovery after photobleaching (FRAP) measurements to further probe the effect of strain on diffusive transport. We find that diffusivity perpendicular to the strain axis decreases with increasing strain, while diffusivity along the strain axis remains unchanged. Our results suggest that the properties of the fibrin network have evolved to protect mechanically loaded fibrin from degradation, consistent with its function in wound healing. The pronounced effect of strain upon diffusivity and proteolytic susceptibility within fibrin networks offers a potentially useful means of guiding cell growth and morphology in fibrin-based biomaterials.

BMPs are mediators in tissue crosstalk of the regenerating musculoskeletal system

The musculoskeletal system is a tight network of many tissues. Coordinated interplay at a biochemical level between tissues is essential for development and repair. Traumatic injury usually affects several tissues and represents a large challenge in clinical settings. The current demand for potent growth factors in such applications thus accompanies the keen interest in molecular mechanisms and orchestration of tissue formation. Of special interest are multitasking growth factors that act as signals in a variety of cell types, both in a paracrine and in an autocrine manner, thereby inducing cell differentiation and coordinating not only tissue assembly at specific sites but also maturation and homeostasis. We concentrate here on bone morphogenetic proteins (BMPs), which are important crosstalk mediators known for their irreplaceable roles in vertebrate development. The molecular crosstalk during embryonic musculoskeletal tissue formation is recapitulated in adult repair. BMPs act at different levels from the initiation to maturation of newly formed tissue. Interestingly, this is influenced by the spatiotemporal expression of different BMPs, their receptors and co-factors at the site of repair. Thus, the regenerative potential of BMPs needs to be evaluated in the context of highly connected tissues such as muscle and bone and might indeed be different in more poorly connected tissues such as cartilage. This highlights the need for an understanding of BMP signaling across tissues in order to eventually improve BMP regenerative potential in clinical applications. In this review, the distinct members of the BMP family and their individual contribution to musculoskeletal tissue repair are summarized by focusing on their paracrine and autocrine functions.