The use of integrin binding domain loaded hydrogel (RGD) with minimally invasive surgical technique in treatment of periodontal intrabony defect: a randomized clinical and biochemical study

Abstract Periodontal regeneration faces multiple challenges, the most important being cellular insufficiency. In an attempt to improve defect cellularity, we aimed to demonstrate enhancing cellular attraction using arginine-glycine-aspartic acid (RGD) adhesion molecule legend blended hydrogel within the intrabony defects. Methodology Forty-five intrabony defects were selected from patients with stage III or IV - grade A or B periodontitis and divided randomly into three equal groups of 15 each: group1 (G1): received minimally invasive surgical technique (MIST) alone, group2 (G2): received MIST and placebo hydrogel injection, and group3 (G3): were treated with MIST and RGD hydrogel injection. Primary outcomes 6 months following therapy were; defect base fill (DBF) and defect width measurement (DW); secondary outcomes were clinical attachment level (CAL), pocket depth (PD), plaque index (PI), gingival index (GI), and biochemical analysis of bone morphogenetic protein (BMP-2) evaluated at 1,7,14 and 21 days following therapy. Results Significant improvements in DBF, CAL, and PD were observed in the three studied groups 6 months following therapy compared to baseline (p<0.05). A significant improvement in DBF was reported in G3 compared to G1 and 2 (p=0.005). Additionally, a significantly higher CAL gain was reported in G3 compared to that of G1 (p=0.02). Group 3 was associated with a significantly higher level of BMP-2 compared to G1 and G2 in all reported periods. Conclusion RGD peptide carried on a hydrogel delivery agent and contained with a minimally invasive flap could be a reliable option in improving the outcomes of periodontal therapy.

RGD peptide inhibits tumor growth by affecting angiogenesis related signaling pathway of laryngeal cancer stem cells / El péptido RGD inhibe el crecimiento tumoral al afectar la vía de señalización relacionada con la angiogénesis de las células madre del cáncer de laringe

SUMMARY: This study is to investigate the role and mechanism of RGD peptide in laryngeal cancer stem cells (CSCs). Laryngeal cancer CD133+Hep-2 CSCs were sorted by flow cytometry. RGD peptide was co-cultured with sorted laryngeal CSCs. Cell proliferation was detected with CCK-8 assay. The mRNA levels of VEGF/VEGFR2/STAT 3/HIF-1α were detected with RT-PCR. The proteins of VEGF/ VEGFR2/STAT 3/HIF-1α were detected with Western blot. The sorted CSCs were inoculated into nude mice. Tumor volume was measured. Integrin αvβ3 expression in tumor tissues was analyzed with immunohistochemistry. The results showed that the ratio of CD133+ CSCs to the total number of cells was 1.34±0.87 %, while CD133-non-tumor stem cells accounted for 95.0±5.76 %. The sorted cancer stem cells grew well. The RGD peptide significantly inhibited the proliferation of CD133+Hep-2 laryngeal CSCs in a dose-dependent manner. The RGD peptide significantly inhibited the mRNA of VEGFR2, STAT3 and HIF-1α in laryngeal CSCs in a concentration-dependent manner. Consistently, the RGD peptide significantly inhibited the protein expression of VEGFR2, STAT3 and HIF-1α in laryngeal CSCs in a dose-dependent manner. At the same time, in vivo tumor experiments showed that the RGD peptide significantly inhibited tumor volume but not the body weight. Furthermore, RGD peptide significantly inhibited the expression of tumor angiogenesis-related protein integrin αvβ3. Our findings demonstrate that RGD peptide inhibits tumor cell proliferation and tumor growth. The underlying mechanism may that RGD inhibits tumor angiogenesis-related signaling pathways, thus affecting the tumor angiogenesis, and decreasing the progression of human laryngeal CSCs.

Este estudio se realizó para investigar el papel y el mecanismo del péptido RGD en las células madre del cáncer de laringe (CSC). Las CSC CD133+Hep-2 de cáncer de laringe se clasificaron mediante citometría de flujo. El péptido RGD se cocultivó con CSC laríngeas clasificadas. La proliferación celular se detectó con el ensayo CCK-8. Los niveles de ARNm de VEGF/VEGFR2/ STAT 3/HIF-1α se detectaron con RT-PCR. Las proteínas de VEGF/ VEGFR2/STAT 3/HIF-1α se detectaron con Western blot. Las CSC clasificadas se inocularon en ratones nudos. Se midió el volumen del tumor. La expresión de integrina αvβ3 en tejidos tumorales se analizó con inmunohistoquímica. Los resultados mostraron que la proporción de CSC CD133+ con respecto al número total de células fue de 1,34 ± 0,87 %, mientras que las células madre no tumorales CD133 representaron el 95,0 ± 5,76 %. Las células madre cancerosas clasificadas crecieron bien. El péptido RGD inhibió significativamente la proliferación de CSC laríngeas CD133+Hep-2 de una manera dependiente de la dosis. El péptido RGD inhibió significativamente el ARNm de VEGFR2, STAT3 y HIF-1α en CSC laríngeas de manera dependiente de la concentración. De manera consistente, el péptido RGD inhibió significativamente la expresión proteica de VEGFR2, STAT3 y HIF-1α en CSC laríngeas, de manera dependiente de la dosis. Al mismo tiempo, los experimentos con tumores in vivo mostraron que el péptido RGD inhibía significativamente el volumen del tumor pero no el peso corporal. Además, el péptido RGD inhibió significativamente la expresión de la proteína integrina αvβ3 relacionada con la angiogénesis tumoral. Nuestros hallazgos demuestran que el péptido RGD inhibe la proliferación de células tumorales y el crecimiento tumoral. El mecanismo subyacente puede ser que RGD inhiba las vías de señalización relacionadas con la angiogénesis tumoral, afectando así la angiogénesis tumoral y disminuyendo la progresión de las CSC laríngeas humanas.

The anti-glioma effects of borneol and RGD co-modified docetaxel loaded nanoparticles after intranasal administration / 药学学报

Borneol (Bo) and Arg-Gly-Asp (RGD) co-modified docetaxel (DTX) loaded MPEG-PLGA nanoparticles (DTX-Bo-RGD-NPs) were prepared to improve the therapeutic effect of DTX against glioma after intranasal administration. DTX-Bo-RGD-NPs were prepared by emulsification-solvent evaporation method, and their morphology, particle size, zeta potential, drug loading capacity (DLC), stability, and in vitro release properties were investigated. The fluorescence probe coumarin-6 loaded NPs were prepared for investigating the NPs' uptake property on C6 and 16HBE cell models to evaluate in vitro targeting ability. The DiR loaded NPs were prepared for observing the fluorescence intensity at the brain tumor site after intranasal administration through in vivo imaging system in a C6 rat orthotropic model, evaluating the targeting ability in vivo. The anti-tumor effects of DTX-Bo-RGD-NPs were also investigated in such C6 rat orthotropic model in vivo. Animal welfare and experimental procedures are in compliance with the regulations of the Animal Ethics Committee of Shanghai University of Traditional Chinese Medicine. The results showed that DTX-Bo-RGD-NPs were spherical and uniformly distributed, with a particle size of about 140 nm and a zeta potential of -20 to -30 mV. The drug delivery system showed good stability and sustained release property in vitro, and favorable brain tumor targeting effect in vitro and in vivo. Such novel drug delivery system significantly improved the accumulation of DTX-Bo-RGD-NPs in tumor sites and displayed a higher brain tumor targeting efficiency, providing promising therapeutics of DTX for the treatment of glioma after intranasal administration.

Synergistic Effect of Cold Plasma Treatment and RGD Peptide Coating on Cell Proliferation over Titanium Surfaces

The aim of this study was to investigate the synergistic effect of cold atmospheric plasma (CAP) treatment and RGD peptide coating for enhancing cellular attachment and proliferation over titanium (Ti) surfaces. The surface structure of CAP-treated and RGD peptide-coated Ti discs were characterized by contact angle goniometer and atomic force microscopy. The effect of such surface modification on human bone marrow derived mesenchymal stem cells (hMSCs) adhesion and proliferation was assessed by cell proliferation and DNA content assays. Besides, hMSCs' adhesion and morphology on surface modified Ti discs were observed via fluorescent and scanning electron microscopy. RGD peptide coating following CAP treatment significantly enhanced cellular adhesion and proliferation among untreated, CAP-treated and RGD peptide-coated Ti discs. The treatment of Ti surfaces with CAP may contribute to improved RGD peptide coating, which enables increased cellular integrations with the Ti surfaces.

Progress on radionuclide-labeled small peptides in targeting tumor angiogenesis / 中国肿瘤临床

Early diagnosis and precision medicine generally show significant differences in the prognosis of patients with carcinoma. Angiogenesis not only plays a key role in tumor pathophysiology but also acts as an important drug target. Peptides with specific se-quences can target specific molecules on the endothelial cellular membrane during tumor angiogenesis. Radionuclide-labeled molecu-lar probes exhibit many advantages in oncotherapy. This article focuses on the progress of radionuclide-labeled RGD and RRL in radio-immunoimaging and radioimmunotherapy targeting tumor angiogenesis.

PRGD composite nerve conduit in repair of human peripheral nerve defect in upper extremity / 中华显微外科杂志

Objective To explore the clinical efficacy of PRGD composite nerve conduit in the treatment of human large-diameter,critical peripheral nerve defect in upper extremity.Methods From December,2011 to August,2014,19 patients with large-diameter,critical peripheral nerve defect in upper extremity were treated with PRGD composite nerve conduit.The patients were followeded-up periodically.The sensory and motor function recovery,high frequency ultrasound,and EMG were employed to assess the efficacy.Results The patients were followed up for an average time of 12-32 months(mean 21.75 ± 6.86 months),sensory and motor function recovered excellent in 7 patients,satisfactory in 7 patients,tolerable in 3 patients and no improvement in 2 patients were obtained according to the peripheral nerve function assessment standard built by British medical research council,the rate excellent and satisfactory results was 73.7％.Conclusion It is clinically promising to use PRGD composite nerve conduit to repair large-diameter,critical peripheral nerve defect in upper extremity,thus laying a foundation for its further application in clinical practice.

Preparation of RGD-targeted Microbubble Contrast Agent and Its Adhesion Efifcacy / 中国医学影像学杂志

PurposeTo develop a novel RGD microbubbles (RGD-MBs) and to evaluate the targeted binding effect with endothelial cells in vitro.Materials and MethodsThe RGD peptide was coated onto the microbubbles through biotin-avidin linkage including 10 μg/ml and 30 μg/ml groups. The microbubbles not carrying RGD peptide were obtained as negative control. Blocking studies were performed with pre-incubation of the cells with RGD peptide for 2 hours. The microbubbleswere characterized by Accusizer 780 and optical microscope. The binding specificity of RGD-MBs withανβ3-expressing mouse endothelial cells was determined with competitive inhibition experiments in vitro. The attachment study was performed using parallel plate flow chamber to investigate the dynamic adhesion on endothelial cells at various shear stresses.ResultsThe RGD-MBs had an average diameter of (4.09±0.07) μm. The binding RGD-MBs per cell were 2.98±0.35 for 10 μg/ml RGD and 1.78±0.23 for 30 μg/ml RGD. RGD-MBs binding to mouse endothelial cells decreased 54.64% and 67.00% in the presence of RGD peptide at a concentration of 10 μg/ml and 30 μg/ml respectively. When the shear stress was under 1.5 dyne/cm2, the accumulation rate was increased with the increase of shear stress (P1.5 dyne/cm2 (P<0.05). Conclusion The RGD-MBs can specifically bind to endothelial cells, indicating its usefulness as ultrasonic molecular probe in monitoring integrinανβ3 expression during tumor angiogenesis, and is potentially valuable for in tumor early-staging and prognosis.

Osteogenic molecules for clinical applications: improving the BMP-collagen system

Among the osteogenic growth factors used for bone tissue engineering, bone morphogenetic proteins (BMPs) are the most extensively studied for use in orthopaedic surgery. BMP-2 and BMP-7 have been widely investigated for developing therapeutic strategies and are the only two approved for use in several clinical applications. Due to the chemical and biological characteristics of these molecules, their authorised uses are always in combination with a carrier based on collagen type I. Although the use of these growth factors is considered safe in the short term, the very high doses needed to obtain significant osteoinduction make these treatments expensive and their long-term safety uncertain, since they are highly pleiotropic and have the capacity to induce ectopic ossification in the surrounding tissues. Therefore it is necessary to improve the currently used BMP-collagen system in terms of efficiency, biosecurity and costs. There are several strategies to increase the clinical effectiveness of these treatments. In this review we summarize the most promising results and our related work focused on this field through two different approaches: i) the development of recombinant BMPs with additional features, and ii) complementing these systems with other growth factors or molecules to enhance or accelerate osteogenesis.

Physical stability of arginine-glycine-aspartic acid peptide coated on anodized implants after installation

PURPOSE: The aim of this study was to evaluate the stability of arginine-glycine-aspartic acid (RGD) peptide coatings on implants by measuring the amount of peptide remaining after installation. MATERIALS AND METHODS: Fluorescent isothiocyanate (FITC)-fixed RGD peptide was coated onto anodized titanium implants (width 4 mm, length 10 mm) using a physical adsorption method (P) or a chemical grafting method (C). Solid Rigid Polyurethane Foam (SRPF) was classified as either hard bone (H) or soft bone (S) according to its density. Two pieces of artificial bone were fixed in a customized jig, and coated implants were installed at the center of the boundary between two pieces of artificial bone. The test groups were classified as: P-H, P-S, C-H, or C-S. After each installation, implants were removed from the SRPF, and the residual amounts and rates of RGD peptide in implants were measured by fluorescence spectrometry. The Kruskal-Wallis test was used for the statistical analysis (alpha=0.05). RESULTS: Peptide-coating was identified by fluorescence microscopy and XPS. Total coating amount was higher for physical adsorption than chemical grafting. The residual rate of peptide was significantly larger in the P-S group than in the other three groups (P<.05). CONCLUSION: The result of this study suggests that coating doses depend on coating method. Residual amounts of RGD peptide were greater for the physical adsorption method than the chemical grafting method.

RGD-modified polylactide-co-glycolic acid tissue engineering scaffolds for bone regeneration: An advance / 第二军医大学学报

Polylactide-co-glycolic acid (PLGA) tissue engineering scaffolds play an important role in the regeneration of bone and cartilage. Due to the poor hydrophilicity of PLGA, it is difficult for cells to attach to the scaffolds. Modification by RGD (Arg-Gly-Asp) peptides can effectively improve the cellular affinity of PLGA and adhesion and proliferation of the seed cells. This review summarizes the recent progress in PLGA tissue engineering scaffolds modified by RGD peptides.

Study on the cell compatibility of polystyrene plate chemically modified by RGD peptides / 国际生物医学工程杂志

Objective To investigate the cell compatibility of polystyrene(PS) plate chemically modified with RGD peptides.Methods PS surfaces were carboxylated by permanganate oxidation in diluted sulfuric acid,and carboxyls were activated with water-soluble carbodiimide to graft with gelatin,collagen and RGD peptides.IR,X-ray photo-electronic spectroscopy (XPS) and dynamic contact angle were used to characterize the surface modification of PS surface.Results XPS results confirmed the existence of nitrogen element from protein molecules and the covalently binding of proteins to PS surfaces.Dynamic contact angle measurement indicated hydrophilicity of PS surfaces was improved obviously after grafting modification.The cell culture results showed that the cell adhesion and proliferation was better on modified surfaces than the initial.Conclusion The cell compatibility of PS surface was great improved after modification with RGD peptides,which would provide a potential strategy to improve the culture of purified endothelial progenitor cells isolated by immunomagnetic beads.

Synthesis and antiangiogenic properties of 2-methoxestradiol-RGD peptide conjugates / 中国药科大学学报

A series of 2-methoxyestradiol (2-MeO-E2) RGD peptide conjugates with coupling RGD peptides to 3- position or 17-position of 2-MeO-E2 through space linker were synthesized. Their antiangiogenic properties were preliminarily evaluated by cell migration scratch assays against HUVECs. Compound 26c binding RGDV peptide showed the best inhibitory effect. In addition, all 2-MeO-E2 RGD peptide conjugates exhibited obvious activity. These results demonstrate that conjugates with RGD peptides represent a promising means for targeting angiogenesis in cancer therapy.

Effect of RGD peptide coating of implant titanium surface on human mesenchymal stem cell response / 대한치과보철학회지

PURPOSE: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. MATERIALS AND METHODS: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). RESULTS: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). CONCLUSION: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

A study of the osteoblasts adhesion, growth and proliferation on the surface of pure titanium immobilized by RGD peptide / 实用口腔医学杂志

Objective: To evaluate the effect of pure titanium modified by bioadhesive RGD peptide on the early attachment, growth and proliferation of osteoblasts. Methods: The titanium samples were hydroxylated by alkali/hot water aging and sol-gel layer-by-layer deposition technique. Afterwards, the terminal -NH_2 group was introduced to the titanium surface by organosilane APTMS self-assembled monolayers and the functional group -NH_2 was further reacted with EDC/NHS by which RGD peptides was covalently immobilized to titanium. The efficiency of this bioreactive surface in promoting cell attachment and the competitive inhibition effect of RGD peptide with different concentrations were observed by calculating the amount of osteoblasts attached on the modified titanium. The growth and proliferation were observed by MTT method and scanning electronic microscopy. Results: The cell adhesion percentage of the RGD modified titanium group was much higher than that of the other groups. The RGD peptide solutions with higher concentration had stronger inhibitory impact on the cell adhesion onto the titanium surface. The cell growth, morphology and proliferation on the RGD peptide modified titanium were better than other groups. Conclusion: Bioadhesive peptide can be chemically grafted onto the titanium surface by means of self-assembled monolayers technique. The cells′ biological behaviors on the surface of RGD immobilized titanium are greatly improved in vitro.

Effect of RGD-modified Silk Material on the Adhesion and Proliferation of Bone Marrow-derived Mesenchymal Stem Cells / 华中科技大学学报（医学）（英德文版）

In order to investigate the effect ofArg-Gly-Asp (RGD) peptide-modified silk biomaterial on the adhesion and proliferation of bone marrow-derived mesenchymal stem cells (MSCs),MSCs of third generation were seeded onto the surface of RGD-decorated silk (silk-RGD group),silk alone (silk group) or tissue culture plate (TCP group).After incubation for 4 or 12 h,MSCs were examined quantitatively by using precipitation method for cell attachment.The cell proliferation,which was de-fined as cell density,was compared among the three groups after culture for 1,2,3,and 4 days.Cell skeleton,which was labeled fluorescently,was observed under laser confocal microscope after 24 h of culture.The results showed that cell adhesion rate in silk-RGD group was higher than in silk group (P<0.05),but similar to that in TCP group after incubation for 4 or 12 h (P>0.05).There were no sig-nificant differences in the cell proliferation among the three groups at different time points (P>0.05 for all).Laser confocal microscopy revealed that in silk-RGD group,MSCs,strongly fluorescently stained,spread fully,with stress fibers clearly seen,while in silk group,actin filaments were sparsely aligned and less stress fibers were found.It was concluded that RGD peptide could improve the ad-hesion of MSCs to the silk scaffold,but had no impact on the proliferation of the cells.