Regulatory T cell-derived exosome mediated macrophages polarization for osteogenic differentiation in fracture repair.

Refractory fracture presents an intractable challenge in trauma treatment. Selective polarization of macrophages as well as the recruitment of osteogenic precursor cells play key roles in osteogenic differentiation during fracture healing. Here we constructed regulatory T cell (Treg)-derived exosomes (Treg-Exo) for the treatment of fracture. The obtained exosomes displayed a spheroid shape with a hydrated particle size of approximately 130 nm. With further purification using CD39 and CD73 antibody-modified microfluidic chips, CD39 and CD73 specifically expressing exosomes were obtained. This kind of Treg-Exo utilized the ectonucleotidases of CD39 and CD73 to catalyze the high level of ATP in the fracture area into adenosine. The generated adenosine further promoted the selective polarization of macrophages. When interacting with mesenchymal stem cells (MSCs, osteogenic precursor cells), both Treg-Exo and Treg-Exo primed macrophages facilitated the proliferation and differentiation of MSCs. After administration in vivo, Treg-Exo effectively promoted fracture healing compared with conventional T cell-derived exosome. To further improve the delivery efficacy of exosomes and integrate multiple biological processes of fracture healing, an injectable hydrogel was fabricated to co-deliver Treg-Exo and stromal cell-derived factor 1 alpha (SDF-1α). With the dual effect of Treg-Exo for macrophage polarization and SDF-1α for MSC recruitment, the multifunctional hydrogel exerted a synergistic effect on fracture repair acceleration. This study provided a promising therapeutic candidate and synergistic strategy for the clinical treatment of fracture.

Protective Effects of Engineered Lactobacillus crispatus on Intrauterine Adhesions in Mice via Delivering CXCL12.

Endometrial injury is the main cause of intrauterine adhesions (IUA), and there is currently no effective prevention and treatment. Immune cells play an important role in damage repair by sensing the change in the microenvironment. Exogenous CXCL12 can promote tissue regeneration and repair by recruiting immune cells, but its effect and possible mechanism on endometrial regeneration and repair have not been reported. In the present study, we constructed an engineered a Lactobacillus crispatus strain by transforming a pMG36e plasmid carrying a CXCL12 gene into the bacterium, and developed two animal models, the intrauterine adhesion mice with or without diabetes to evaluate the positive effects of this strain on the prevention of IUA after accepting intrauterine surgery in normal and diabetic mice. The results showed that vaginal application of L. crispatus-pMG36e-mCXCL12 strains significantly diminished the levels of pro-inflammatory factors interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) in serum and uterine tissues of IUA mice, and resulted in the inhibition of the inflammatory (toll-like receptor 4/nuclear factor-κb, TLR4/NF-κB) and fibrotic (transforming growth factor-ß1/smads, TGF-ß1/Smads) signalling pathways in the uterine tissues. The high-throughput sequencing results further indicated that treatment with L. crispatus-pMG36e-mCXCL12 strains greatly increased the abundance of Lactobacillus spp. and reduced that of the pathogenic Klebsiella spp. in IUA mice. Furthermore, among intrauterine adhesion mice with diabetes, we obtained similar results to non-diabetic mice, that is, L.crispatus-pMG36e-mCXCL12 significantly improved fibrosis and inflammation in the uterine cavity of diabetic mice, and restored the vaginal microbiota balance in diabetic mice. Therefore, we speculated that vaginal administration of L. crispatus-pMG36e-mCXCL12 strains can effectively alleviate intrauterine adhesions by restoring the microbial balance and reducing inflammation and fibrosis caused by surgery.

Development of a Gene-Activated Scaffold Incorporating Multifunctional Cell-Penetrating Peptides for pSDF-1α Delivery for Enhanced Angiogenesis in Tissue Engineering Applications.

Non-viral gene delivery has become a popular approach in tissue engineering, as it permits the transient delivery of a therapeutic gene, in order to stimulate tissue repair. However, the efficacy of non-viral delivery vectors remains an issue. Our lab has created gene-activated scaffolds by incorporating various non-viral delivery vectors, including the glycosaminoglycan-binding enhanced transduction (GET) peptide into collagen-based scaffolds with proven osteogenic potential. A modification to the GET peptide (FLR) by substitution of arginine residues with histidine (FLH) has been designed to enhance plasmid DNA (pDNA) delivery. In this study, we complexed pDNA with combinations of FLR and FLH peptides, termed GET* nanoparticles. We sought to enhance our gene-activated scaffold platform by incorporating GET* nanoparticles into collagen-nanohydroxyapatite scaffolds with proven osteogenic capacity. GET* N/P 8 was shown to be the most effective formulation for delivery to MSCs in 2D. Furthermore, GET* N/P 8 nanoparticles incorporated into collagen-nanohydroxyapatite (coll-nHA) scaffolds at a 1:1 ratio of collagen:nanohydroxyapatite was shown to be the optimal gene-activated scaffold. pDNA encoding stromal-derived factor 1α (pSDF-1α), an angiogenic chemokine which plays a role in BMP mediated differentiation of MSCs, was then delivered to MSCs using our optimised gene-activated scaffold platform, with the aim of significantly increasing angiogenesis as an important precursor to bone repair. The GET* N/P 8 coll-nHA scaffolds successfully delivered pSDF-1α to MSCs, resulting in a significant, sustained increase in SDF-1α protein production and an enhanced angiogenic effect, a key precursor in the early stages of bone repair.

Rh-CXCL-12 Attenuates Neuronal Pyroptosis after Subarachnoid Hemorrhage in Rats via Regulating the CXCR4/NLRP1 Pathway.

Subarachnoid hemorrhage (SAH) is a cerebrovascular disease associated with high morbidity and mortality. CXCR4 provides neuroprotective effects, which can alleviate brain injury and inflammation induced by stroke. Previous studies have suggested that CXCR4 reduces the pyroptosis of LPS-stimulated BV2 cells. The purpose of this study was to evaluate the antipyroptosis effects and mechanisms of CXCR4 after SAH. SAH animal model was induced via endovascular perforation. A total of 136 male Sprague-Dawley rats were used. Recombinant human cysteine-X-cysteine chemokine ligand 12 (rh-CXCL-12) was administered intranasally at 1 h after SAH induction. To investigate the underlying mechanism, the inhibitor of CXCR4, AMD3100, was administered intraperitoneally at 1 h before SAH. The neurobehavior tests were assessed, followed by performing Western blot and immunofluorescence staining. The Western blot results suggested that the expressions of endogenous CXCL-12, CXCR4, and NLRP1 were increased and peaked at 24 h following SAH. Immunofluorescence staining showed that CXCR4 was expressed on neurons, microglia, and astrocytes. Rh-CXCL-12 treatment improved the neurological deficits and reduced the number of FJC-positive cells, IL-18-positive neurons, and cleaved caspase-1(CC-1)-positive neurons after SAH. Meanwhile, rh-CXCL-12 treatment increased the levels of CXCL-12 and CXCR4, and reduced the levels of NLRP1, IL-18, IL-1ß, and CC-1. Moreover, the administration of AMD3100 abolished antipyroptosis effects of CXCL-12 and its regulation of CXCR4 post-SAH. The CXCR4/NLRP1 signaling pathway may be involved in CXCL-12-mediated neuronal pyroptosis after SAH. Early administration of CXCL-12 may be a preventive and therapeutic strategy against brain injury after SAH.

Therapeutic Strategies for IVD Regeneration through Hyaluronan/SDF-1-Based Hydrogel and Intravenous Administration of MSCs.

Intervertebral disc (IVD) degeneration involves a complex cascade of events, including degradation of the native extracellular matrix, loss of water content, and decreased cell numbers. Cell recruitment strategies for the IVD have been increasingly explored, aiming to recruit either endogenous or transplanted cells. This study evaluates the IVD therapeutic potential of a chemoattractant delivery system (HAPSDF5) that combines a hyaluronan-based thermoreversible hydrogel (HAP) and the chemokine stromal cell derived factor-1 (SDF-1). HAPSDF5 was injected into the IVD and was combined with an intravenous injection of mesenchymal stem/stromal cells (MSCs) in a pre-clinical in vivo IVD lesion model. The local and systemic effects were evaluated two weeks after treatment. The hydrogel by itself (HAP) did not elicit any adverse effect, showing potential to be administrated by intradiscal injection. HAPSDF5 induced higher cell numbers, but no evidence of IVD regeneration was observed. MSCs systemic injection seemed to exert a role in IVD regeneration to some extent through a paracrine effect, but no synergies were observed when HAPSDF5 was combined with MSCs. Overall, this study shows that although the injection of chemoattractant hydrogels and MSC recruitment are feasible approaches for IVD, IVD regeneration using this strategy needs to be further explored before successful clinical translation.

Mesenchymal Stem Cells Pretreatment With Stromal-Derived Factor-1 Alpha Augments Cardiac Function and Angiogenesis in Infarcted Myocardium.

BACKGROUND: Stem cell therapy is among the novel approaches for the treatment of post-myocardial infarction cardiomyopathy. This study aims to compare the effect of stromal-derived factor 1 α (SDF1α), mesenchymal stem cells (MSCs) in combination with the lentiviral production of vascular endothelial growth factor (VEGF) on infarct area, vascularization and eventually cardiac function in a rat model of myocardial infarction (MI). METHODS: The influence of SDf1α on MSCs survival was investigated. MSCs were transduced via a lentiviral vector containing VEGF. After that, the effect of mesenchymal stem cell transfection of VEGF-A165 and SDf1α preconditioning on cardiac function and scar size was investigated in five groups of MI rat models. The MSC survival, cardiac function, scar size, angiogenesis, and lymphocyte count were assessed 72 hours and 6 weeks after cell transplantation. RESULTS: SDF1α decreased the lactate dehydrogenase release in MSCs significantly. Also, the number of viable cells in the SDF1α-pretreated group was meaningfully more than the control. The left ventricular systolic function significantly enhanced in groups with p240MSC, SDF1αMSC, and VEGF-A165MSC in comparison to the control group. CONCLUSIONS: These findings suggest that SDF1α pretreatment and overexpressing VEGF in MSCs could augment the MSCs' survival in the infarcted myocardium, reduce the scar size, and improve the cardiac systolic function.

Sustained release of collagen-affinity SDF-1α from book-shaped acellular fibrocartilage scaffold enhanced bone-tendon healing in a rabbit model.

Rapid and functional bone-tendon (B-T) healing remains a difficulty in clinical practice. Tissue engineering has emerged as a promising strategy to address this problem. However, the majority of tissue engineering scaffolds are loaded with stem cells to enhance the regenerability in B-T healing, which is complicated and inconvenient for clinical application. Accordingly, developing a cell-free scaffold with chemotactic function and chondrogenic inducibility may be an effective approach. In this study, a collagen affinity peptide derived from the A3 domain of von Willebrand factor (a hemostasis factor) was fused into the C-terminal of a stromal cell-derived factor-1α (SDF-1α) to synthesize a recombinant SDF-1α capable of binding collagen and chemotactic activity. The recombinant SDF-1α was then tethered on the collagen fibers of a book-shaped acellular fibrocartilage scaffold (BAFS), thus fabricating a novel scaffold (C-SDF-1α/BAFS) with chemotactic function and chondrogenic inducibility. In vitro tests determined that this scaffold was noncytotoxic and biomimetic, could attract stem cells migrating to the scaffold using sustainably released C-SDF-1α, and inducedthe interacting stem cells down the chondrogenic lineage. In vivo, the C-SDF-1α/BAFS significantly enhanced the B-T healing in a rabbit partial patellectomy model, as shown by the larger cartilaginous metaplasia region, better fibrocartilage regeneration, additional bone formation, and improved biomechanical properties. Therefore, the findings of the study demonstrate that the C-SDF-1α/BAFS could potentially be applied for B-T healing.

In vitro study of SDF-1α-loaded injectable and thermally responsive hydrogels for adipose stem cell therapy by SDF-1/CXCR4 axis.

Stem cell-based approaches have become a promising therapeutic strategy for treating ischemic diseases. The aim of this study was to develop injectable hydrogel systems for the local release of stromal cell-derived factor-1α (SDF-1α) to recruit adipose stem cells (ASCs) that express CXCR4 to achieve stem cell therapy and therapeutic angiogenesis. Thermoresponsive and injectable chitosan (CS)/ß-glycerophosphate disodium salt pentahydrate (ßGP) hydrogels with different concentrations of hyaluronic acid (HA) were designed and fabricated to achieve local and sustained release of SDF-1α for ASC recruitment. Herein, the material structures, physical properties, gelation temperature, and gelation time of hydrogels with different compositions were determined. The incorporation of 0.9% HA in CS-based hydrogels not only enhanced the gelation time but also increased the strength of the hydrogels. In addition, the results revealed that the thermoresponsive and injectable CS/ßGP/HA hydrogels showed good biocompatibility. In addition, the in vitro release profiles showed that the hydrogels achieved sustained release of SDF-1α over 7 days and enhanced ASC migration. The results revealed that the hydrogels with HA enhanced the sustained release effect compared with the hydrogel without HA, indicating that the HA content regulated the physical and release properties of the injectable hydrogels. Therefore, thermoresponsive and injectable CS/ßGP/HA hydrogels may provide an alternative for treating ischemic diseases via SDF-1/CXCR4 axis for ASC recruitment and retention.

Adipose-derived stem cells in wound healing of full-thickness skin defects: a review of the literature.

The complex process of wound healing can be delayed in circumstances when the natural niche is extremely altered. Adipose-derived stem cells (ADSC) seem to be a promising therapy for these type of wounds. We aim to describe the studies that used ADSC for wound healing after a full-thickness skin defect, the ADSC mechanisms of action, and the outcomes of the different ADSC therapies applied to date. We performed a review by querying PubMed database for studies that evaluated the use of ADSC for wound healing. The Mesh terms, adipose stem cells AND (skin injury OR wound healing) and synonyms were used for the search. Our search recorded 312 articles. A total of 30 articles met the inclusion criteria. All were experimental in nature. ADSC was applied directly (5 [16.7%]), in sheets (2 [6.7%]), scaffolds (14 [46.7%]), skin grafts (3 [10%]), skin flaps (1 [3.3%]), as microvesicles or exosomes (4 [13.3%]), with adhesives for wound closure (1 [3.3%]), and in a concentrated conditioned hypoxia-preconditioned medium (1 [3.3%]). Most of the studies reported a benefit of ADSC and improvement of wound healing with all types of ADSC therapy. ADSC applied along with extracellular matrix, stromal cell-derived factor (SDF-1) or keratinocytes, or ADSC seeded in scaffolds showed better outcomes in wound healing than ADSC alone. ADSC have shown to promote angiogenesis, fibroblast migration, and up-regulation of macrophages chemotaxis to enhance the wound healing process. Further studies should be conducted to assure the efficacy and safety of the different ADSC therapies.

Chemokine receptor CXCR4 activates the RhoA/ROCK2 pathway in spinal neurons that induces bone cancer pain.

BACKGROUND: Chemokine receptor CXCR4 has been found to be associated with spinal neuron and glial cell activation during bone cancer pain. However, the underlying mechanism remains unknown. Furthermore, the RhoA/ROCK2 pathway serves as a downstream pathway activated by CXCR4 during bone cancer pain. We first validated the increase in the expressions of CXCR4, p-RhoA, and p-ROCK2 in the spinal dorsal horn of a well-characterized tumor cell implantation-induced cancer pain rat model and how these expressions contributed to the pain behavior in tumor cell implantation rats. We hypothesized that spinal blockade of the CXCR4-RhoA/ROCK2 pathway is a potential analgesic therapy for cancer pain management. METHODS: Adult female Sprague-Dawley rats (body weight of 180-220 g) and six- to seven-week old female Sprague-Dawley rats (body weight of 80-90 g) were taken. Ascitic cancer cells were extracted from the rats (body weight of 80-90 g) with intraperitoneally implanted Walker 256 mammary gland carcinoma cells. Walker 256 rat mammary gland carcinoma cells were then injected (tumor cell implantation) into the intramedullary space of the tibia to establish a rat model of bone cancer pain. RESULTS: We found increased expressions of CXCR4, p-RhoA, and p-ROCK2 in the neurons in the spinal cord. p-RhoA and p-ROCK2 were co-expressed in the neurons and promoted by overexpressed CXCR4. Intrathecal delivery of CXCR4 inhibitor Plerixafor (AMD3100) or ROCK2 inhibitor Fasudil abrogated tumor cell implantation-induced pain hypersensitivity and tumor cell implantation-induced increase in p-RhoA and p-ROCK2 expressions. Intrathecal injection of stromal-derived factor-1, the principal ligand for CXCR4, accelerated p-RhoA expression in naive rats, which was prevented by postadministration of CXCR4 inhibitor Plerixafor (AMD3100) or ROCK2 inhibitor Fasudil. CONCLUSIONS: Collectively, the spinal RhoA/ROCK2 pathway could be a critical downstream target for CXCR4-mediated neuronal sensitization and pain hypersensitivity in bone cancer pain, and it may serve as a potent therapeutic target for pain treatment.

Sustained release of stromal cell-derived factor-1 alpha from silk fibroin microfiber promotes urethral reconstruction in rabbits.

We developed a stromal cell-derived factor-1 alpha (SDF-1α)-aligned silk fibroin (SF)/three-dimensional porous bladder acellular matrix graft (3D-BAMG) composite scaffold for long-section ventral urethral regeneration and repair in vivo. SDF-1α-aligned SF microfiber/3D-BAMG, aligned SF microfiber/3D-BAMG, and nonaligned SF microfiber/3D-BAMG scaffolds were prepared using electrostatic spinning and wet processing. Adipose-derived stem cell (ADSC) and bone marrow stromal cell (BMSC) migration was assessed in the SDF-1α-loaded scaffolds. Sustained SDF-1α release in vitro and vivo was analyzed using enzyme-linked immunosorbent assay (ELISA) and western blotting, respectively. The scaffolds were used to repair a 1.5 × 1 cm2 ventral urethral defect in male rabbits in vivo. General observation and retrograde urinary tract contrast assessment were used to examine urethral lumen patency and continuity at 1 and 3 months post-surgery. Postoperative rehabilitation was evaluated using histological detection. The composite scaffolds sustained SDF-1α release for over 16 days in vitro. SDF-1α-aligned SF nanofiber promoted regeneration of urethral mucosa, submucosal smooth muscles, and microvasculature, increased cellular proliferation, and reduced collagen deposition. SDF-1α expression was increased in reconstructed urethra at 3 months post-surgery in SDF-1α-aligned SF group. SDF-1α-aligned SF microfiber/3D-BAMG scaffolds may be used to repair and reconstruct long urethral defects because they accelerate urethral regeneration.

An Injectable Nanocomposite Hydrogel for Potential Application of Vascularization and Tissue Repair.

In this contribution, an injectable hydrogel was developed with chitosan, gelatin, ß-glycerphosphate and Arg-Gly-Asp (RGD) peptide: this hydrogel is liquid in room temperature and rapidly gels at 37 °C; RGD peptide promises better growth microenvironment for various cells, especially endothelial cells (EC), smooth muscle cells (SMC) and mesenchymal stem cells (MSC). Both stromal cell-derived factor-1 (SDF-1) nanoparticle and vascular endothelial growth factor (VEGF) nanoparticles were loaded in the injectable hydrogel to simulate the natural nanoparticles in the extracellular matrix (ECM) to promote angiogenesis. In vitro EC/SMC and MSC/SMC co-culture experiment indicated that the nanocomposite hydrogel accelerated constructing embryonic form of blood vessels, and chick embryo chorioallantoic membrane model demonstrated its ability of improving cells migration and blood vessel regeneration. We injected this nanocomposite hydrogel into rat myocardial infarction (MI) model and the results indicated that the rats heart function recovered better compared control group. We hope this injectable nanocomposite hydrogel may possess wider application in tissue engineering.

Decreased viability and neurite length in neural cells treated with chitosan-dextran sulfate nanocomplexes.

CXCL12 is a chemokine known to regulate migration, proliferation, and differentiation of neural stem cells (NSCs) and to play a neuroprotective role in ischemic stroke. Chitosan-dextran sulfate nanocomplexes (Ch/DS NC) are known nanoparticulated systems used to efficiently deliver heparin-binding factors. Here we evaluate Ch/DS NC as carriers for CXCL12 in a mouse model of stroke. Free CXCL12 reduced the size of the ischemic brain lesion. However, when Ch/DS NC were administrated, the stroke volume increased. Neurotoxic screening revealed that Ch/DS NC reduced neuronal viability, decreased the extension of neurites and impaired NSC migration in vitro. To the best of our knowledge, neurotoxicity of Ch/DS NC has not been reported and further screenings will be needed in order to evaluate the biological safety of these nanocomposites. Our results add new data on nanoparticle neurotoxicity and may help us to better understand the complex interactions of the nanostructures with biological components.

Controlled releasing of SDF-1α in chitosan-heparin hydrogel for endometrium injury healing in rat model.

Herein we report a facile approach for chitosan-heparin hydrogels with controlled release manner and their applications for intrauterine adhesion. The sol precursor was converted to gel at physiological temperature in 15 min. FTIR, SEM and swelling test were performed to characterize their compositions, morphologies and stability. In vitro releasing profiles was investigated in PBS solutions. Intrauterine injured rat model was established and treated with different methods. The results of H&E staining, Masson trichrome staining, western blots assay, immunohistochemical staining and immunofluorescence staining revealed that endogenous c-kit positive stem cells (HSCs) were recruited to the injury site and promoted the wound recovery. After 7 days' treatment, uterus treated with SDF-1α releasing hydrogel showed no difference with control group on endometrial thickness, glands number and fibrosis level. This work provides a possible method for intrauterine adhesion healing.

Intranasal delivery of SDF-1α-preconditioned bone marrow mesenchymal cells improves remyelination in the cuprizone-induced mouse model of multiple sclerosis.

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS) that leads to disability in middle-aged individuals. High rates of apoptosis and inappropriate homing are limitations for the application of stem cells in cell therapy. Preconditioning of bone marrow mesenchymal stem cells (BMSCs) with stromal cell-derived factor 1α (SDF-1α), also called C-X-C motif chemokine 12 (CXCL12), is an approach for improving the functional features of the cells. The aim of this study was to investigate the therapeutic efficacy of intranasal delivery of SDF-1α preconditioned BMSCs in the cuprizone-induced chronically demyelinated mice model. BMSCs were isolated, cultured, and preconditioned with SDF-1α. Then, intranasal delivery of the preconditioned cells was performed in the C57BL/6 mice receiving cuprizone for 12 weeks. Animals were killed at 30 days after cell delivery. SDF-1α preconditioning increased C-X-C chemokine receptor type 4 (CXCR4) expression on the surface of BMSCs, improved survival of the cells, and decreased their apoptosis in vitro. SDF-1α preconditioning also improved CXCL12 level within the brain, and enhanced spatial learning and memory (assessed by Morris water maze [MWM]), and myelination (assessed by Luxol fast blue [LFB] and transmission electron microscopy [TEM]). In addition, preconditioning of BMSCs with SDF-1α reduced the protein expressions of glial fibrillary acidic protein and ionized calcium-binding adapter molecule (Iba-1) and increased the expressions of oligodendrocyte lineage transcription factor-2 (Olig-2) and adenomatous polyposis coli (APC), evaluated by immunofluorescence. The results showed the efficacy of intranasal delivery of SDF-1α-preconditioned BMSCs for improving remyelination in the cuprizone model of MS.

Evaluation of dual release of stromal cell-derived factor-1 and basic fibroblast growth factor with nerve conduit for peripheral nerve regeneration: An experimental study in mice.

BACKGROUND: The development of drug delivery systems has enabled the release of multiple bioactive molecules. The efficacy of nerve conduits coated with dual controlled release of stromal cell-derived factor-1 (SDF-1) and basic fibroblast growth factor (bFGF) for peripheral nerve regeneration was investigated. MATERIALS AND METHODS: Sixty-two C57BL6 mice were used for peripheral nerve regeneration with a nerve conduit (inner diameter, 1 mm, and length, 7 mm) and an autograft. The mice were randomized into five groups based on the different repairs of nerve defects. In the group of repair with conduits alone (n = 9), a 5-mm sciatic nerve defect was repaired by the nerve conduit. In the group of repair with conduits coated with bFGF (n = 10), SDF-1 (n = 10), and SDF-1/bFGF (n = 10), it was repaired by the nerve conduit with bFGF gelatin, SDF-1 gelatin, and SDF-1/bFGF gelatin, respectively. In the group of repair with autografts (n = 10), it was repaired by the resected nerve itself. The functional recovery, nerve regeneration, angiogenesis, and TGF-ß1 gene expression were assessed. RESULTS: In the conduits coated with SDF-1/bFGF group, the mean sciatic functional index value (-88.68 ± 10.64, p = .034) and the axon number (218.8 ± 111.1, p = .049) were significantly higher than the conduit alone group, followed by the autograft group; in addition, numerous CD34-positive cells and micro vessels were observed. TGF-ß1 gene expression relative values in the conduits with SDF-1/bFGF group at 3 days (7.99 ± 5.14, p = .049) significantly increased more than the conduits alone group. CONCLUSION: Nerve conduits coated with dual controlled release of SDF-1 and bFGF promoted peripheral nerve regeneration.

Intra-tracheal administration of a naked plasmid expressing stromal derived factor-1 improves lung structure in rodents with experimental bronchopulmonary dysplasia.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is characterized by alveolar simplification and disordered angiogenesis. Stromal derived factor-1 (SDF-1) is a chemokine which modulates cell migration, proliferation, and angiogenesis. Here we tested the hypothesis that intra-tracheal (IT) administration of a naked plasmid DNA expressing SDF-1 would attenuate neonatal hyperoxia-induced lung injury in an experimental model of BPD, by promoting angiogenesis. DESIGN/METHODS: Newborn Sprague-Dawley rat pups (n = 18-20/group) exposed to room air (RA) or hyperoxia (85% O2) from postnatal day (P) 1 to 14 were randomly assigned to receive IT a naked plasmid expressing SDF-1, JVS-100 (Juventas Therapeutics, Cleveland, Ohio) or placebo (PL) on P3. Lung alveolarization, angiogenesis, inflammation, vascular remodeling and pulmonary hypertension (PH) were assessed on P14. PH was determined by measuring right ventricular systolic pressure (RVSP) and the weight ratio of the right to left ventricle + septum (RV/LV + S). Capillary tube formation in SDF-1 treated hyperoxia-exposed human pulmonary microvascular endothelial cells (HPMEC) was determined by matrigel assay. Data is expressed as mean ± SD and analyzed by two-way ANOVA. RESULTS: Exposure of neonatal pups to 14 days of hyperoxia decreased lung SDF-1 gene expression. Moreover, whilst hyperoxia exposure inhibited capillary tube formation in HPMEC, SDF-1 treatment increased tube length and branching in HPMEC. PL-treated hyperoxia-exposed pups had decreased alveolarization and lung vascular density. This was accompanied by an increase in RVSP, RV/LV + S, pulmonary vascular remodeling and inflammation. In contrast, IT JVS-100 improved lung structure, reduced inflammation, PH and vascular remodeling. CONCLUSIONS: Intratracheal administration of a naked plasmid expressing SDF-1 improves alveolar and vascular structure in an experimental model of BPD. These findings suggest that therapies which modulate lung SDF-1 expression may have beneficial effects in preterm infants with BPD.

Evaluation of bone-regeneration effects and ectopic osteogenesis of collagen membrane chemically conjugated with stromal cell-derived factor-1 in vivo.

Because the collagen membrane lacks osteoinductivity, it must be modified with bioactive components to trigger rapid bone regeneration. In this study, we aimed to evaluate the bone regeneration effects of a collagen membrane chemically conjugated with stromal cell-derived factor-1 alpha (SDF-1α) in rat models. To this end, different collagen membranes from four groups including a control group with a Bio-Oss bone substitute + collagen membrane; physical adsorption group with Bio-Oss + SDF-1α physically adsorbed on the collagen membrane; chemical cross-linking group with Bio-Oss + SDF-1α chemically cross-linked to the collagen membrane; and cell-seeding group with Bio-Oss + bone marrow mesenchymal stem cells (BMSCs) seeded onto the collagen membrane were placed in critical-sized defect models using a guided bone regeneration technique. At 4 and 8 weeks, the specimens were analyzed by scanning electron microscopy, energy-dispersive x-ray spectroscopy, micro-computed tomography, and histomorphology analyzes. Furthermore, ectopic osteogenesis was examined by histological analysis with Von Kossa staining, with the samples counterstained by hematoxylin and eosin and immunohistochemical staining. The results showed that in the chemical cross-linking group and cell-seeding group, the bone volume fraction, bone surface area fraction, and trabecular number were significantly increased and showed more new bone formation compared to the control and physical adsorption groups. Von Kossa-stained samples counterstained with hematoxylin and eosin and subjected to immunohistochemical staining of 4-week implanted membranes revealed that the chemical cross-linking group had the largest number of microvessels. The collagen membrane chemically conjugated with SDF-1α to significantly promote new bone and microvessel formation compared to SDF-1α physical adsorption and showed similar effects on new bone formation as a BMSC seeding method. This study provided a cell-free approach for shortening the bone healing time and improving the success rate of guided bone regeneration.

Effect of SDF-1 with biphasic ceramic-like bone graft on the repair of rabbit radial defect.

BACKGROUND: This study aimed to investigate the effects of stromal cell-derived factor-1 (SDF-1) on biphasic ceramic-like biologic bone (BCBB) in vivo on the repair of large segment bone defect in rabbits. METHODS: A large-segment radius defect model of the rabbits was constructed. In the experimental group, BCBB with SDF-1 sustained-release system were implanted into the bone defect site. Other three groups including normal control, autologous bone graft, and BCBB implantation without SDF-1 were set. After surgery, general observation, X-ray radiography and scoring, and tissue section staining were performed at 2, 4, 8, 12, and 24 weeks post-implantation. RESULTS: By general observation, X-ray radiography and grading and tissue section staining observation, we found that the BCBB carrying SDF-1 was better than those in the group of BCBB without SDF-1 (P < 0.05). BCBB scaffold had certain bone conduction capacity, and the BCBB scaffold carrying SDF-1 had improved bone conduction ability and possessed bone induction ability. In the case of carrying SDF-1, it can be used to repair large bone defects in a shorter time than simply using BCBB, which is equivalent to the effect of autologous bone. CONCLUSION: BCBB scaffold carrying SDF-1 can promote the repair effect on a large bone defect, which is equivalent to the effect of autologous bone.

CXCL12 loaded-dermal filler captures CXCR4 expressing melanoma circulating tumor cells.

Development of distant metastasis relies on interactions between cancer and stromal cells. CXCL12, also known as stromal-derived factor 1α (SDF-1α), is a major chemokine constitutively secreted in bone marrow, lymph nodes, liver and lung, playing a critical role in the migration and seeding of neoplastic cells. CXCL12 activates the CXCR4 receptor that is overexpressed in several human cancer cells. Recent evidence reveals that tumors induce pre-metastatic niches in target organ producing tumor-derived factors. Pre-metastatic niches represent a tumor growth-favoring microenvironment in absence of cancer cells. A commercially available dermal filler, hyaluronic acid (HA) -based gel, loaded with CXCL12 (CLG) reproduced a "fake" pre-metastatic niche. In vitro, B16-hCXCR4-GFP, human cxcr4 expressing murine melanoma cells efficiently migrated toward CLG. In vivo, CLGs and empty gels (EGs) were subcutaneously injected into C57BL/6 mice and 5 days later B16-hCXCR4-GFP cells were intravenously inoculated. CLGs were able to recruit a significantly higher number of B16-hCXCR4-GFP cells as compared to EGs, with reduced lung metastasis in mice carrying CLG. CLG were infiltrated by higher number of CD45-positive leukocytes, mainly neutrophils CD11b+Ly6G+ cells, myeloid CD11b+Ly6G- and macrophages F4/80. CLG recovered cells recapitulated the features of B16-hCXCR4-GFP (epithelial, melanin rich, MELAN A/ S100/ c-Kit/CXCR4 pos; α-SMA neg). Thus a HA-based dermal filler loaded with CXCL12 can attract and trap CXCR4+tumor cells. The CLG trapped cells can be recovered and biologically characterized. As a corollary, a reduction in CXCR4 dependent lung metastasis was detected.