Combination Of Growth Factors Research Articles

The Clinical Effect of a Combination of Mouse Nerve Growth Factor and Methylcobalamin to Treat Lumbar Disc Herniation with Foot Drop: A Retrospective Cohort Study

ObjectiveTo investigate the clinical effect of mouse nerve growth factor (mNGF) and methylcobalamin (MeCbl) for the treatment of lumbar disk herniation (LDH) with foot drop.MethodsA total of 46 patients suffering from LDH with foot drop who underwent transforaminal lumbar interbody fusion (TLIF) surgery in our department from January 2015 to December 2017 were retrospectively analyzed. We divided these patients into two groups according to the different postoperative treatment which independently selected by patients after signing informed consent form: one group of 25 patients was treated with MeCbl alone (Group MeCbl), the other group of 21 patients was treated with a combination of mNGF and MeCbl (Group MeCbl+mNGF). Patient demographics, the visual analogue scale (VAS) scores, sensory and muscular strength improvement statistics at 1 week, 4 weeks, 12 weeks, and 12 months postoperatively were recorded. Motor/sensory deficits, sciatica and overall neurological outcome after treatment of MeCbl alone and combination of mNGF and MeCbl were retrospectively analyzed.ResultsThe follow‐up ranged between 12 and 42 months (mean 20.8 months). There were no significant differences between these two groups of patients with respect to sex ratio, age, smoking, diabetes, disease course, section of protruding disc(s), muscular strength of foot dorsiflexion or preoperative visual analogue scale (VAS) score (P > 0.05). The VAS scores of Group MeCbl+mNGF were significantly lower than Group MeCbl at 1 week, 4 weeks, 12 weeks, and 12 months postoperatively (4.32 ± 0.75 vs 5.25 ± 0.79,2.65 ± 0.48 vs 3.42 ± 0.52, 1.72 ± 0.36 vs 2.45 ± 0.39, 1.12 ± 0.22 vs 1.52 ± 0.24, P < 0.05). The effective rates of sensory improvement were significantly higher in Group MeCbl+mNGF compared with Group MeCbl at 12‐week/12‐month follow‐up time point (90.48% vs 52.00%,95.24% vs 68.00%, P < 0.05). The effective rate of muscular strength improvement of the two groups did not differ significantly at 1 week after surgery but exhibited statistically significant differences at subsequent time points (61.90% vs 32.00%, 76.19% vs 44.00%, 80.95% vs 48.00%, P < 0.05).ConclusionsApplication of mNGF had clinical effects on promoting the recovery of neurological function in patients suffering from LDH with foot drop.

Platelet-Rich Fibrin in Combination with Local Antibiotics Optimizes Wound Healing After Deep Sternal Wound Problems and Prevents Reinfection

Objective: Disturbed wound healing is a significant problem in patients after cardiac surgery. Problems with deep sternal wound healing are rare, but can be quite difficult to treat. Furthermore, the therapy is highly expensive and consumes many of the patient’s personal resources. Another major obstacle in this patient group is reinfection after secondary wound closure. We examined how to prevent early reinfection through the use of growth factors in combination with local antibiotics. Methods: Our study included 232 patients with a deep sternal wound healing problem. After initial vacuum therapy, we planned secondary wound closure. During wound closure, we used only platelet-rich fibrin in a PRF group (109 patients). In another group (123 patients), we covered the wounds intraoperatively with a combination of PRF and local antibiotics (PRF CoDelivery). All patients were observed for 30 days for signs of early surgical site infection. Results: After 30 days, 22 patients (20.2%) in the PRF group showed a persistent problem with wound healing with or without reinfection. In contrast, only 12 patients (9.8%) in the PRF CoDelivery group had this problem (p=0.023 PRF vs. PRF CoDelivery). Conclusion: The combination of growth factors and antibiotics was associated with a significantly reduced incidence of early reinfection and thus can be expected to have a positive impact on wound healing in complicated scenarios. Furthermore, the combination of PRF and local antibiotics was easy to use. Further studies are needed to verify these initial findings.

Pulsating fluid flow affects pre-osteoblast behavior and osteogenic differentiation through production of soluble factors.

Bone mass increases after error‐loading, even in the absence of osteocytes. Loaded osteoblasts may produce a combination of growth factors affecting adjacent osteoblast differentiation. We hypothesized that osteoblasts respond to a single load in the short‐term (minutes) by changing F‐actin stress fiber distribution, in the intermediate‐term (hours) by signaling molecule production, and in the long‐term (days) by differentiation. Furthermore, growth factors produced during and after mechanical loading by pulsating fluid flow (PFF) will affect osteogenic differentiation. MC3T3‐E1 pre‐osteoblasts were either/not stimulated by 60 min PFF (amplitude, 1.0 Pa; frequency, 1 Hz; peak shear stress rate, 6.5 Pa/s) followed by 0–6 h, or 21/28 days of post‐incubation without PFF. Computational analysis revealed that PFF immediately changed distribution and magnitude of fluid dynamics over an adherent pre‐osteoblast inside a parallel‐plate flow chamber (immediate impact). Within 60 min, PFF increased nitric oxide production (5.3‐fold), altered actin distribution, but did not affect cell pseudopodia length and cell orientation (initial downstream impact). PFF transiently stimulated Fgf2, Runx2, Ocn, Dmp1, and Col1⍺1 gene expression between 0 and 6 h after PFF cessation. PFF did not affect alkaline phosphatase nor collagen production after 21 days, but altered mineralization after 28 days. In conclusion, a single bout of PFF with indirect associated release of biochemical factors, stimulates osteoblast differentiation in the long‐term, which may explain enhanced bone formation resulting from mechanical stimuli.

Three dimensional printed nanostructure biomaterials for bone tissue engineering.

The suffering from organ dysfunction due to damaged or diseased tissue/bone has been globally on the rise. Current treatment strategies for non-union bone defects include: the use of autografts, allografts, synthetic grafts and free vascularized fibular grafts. Bone tissue engineering has emerged as an alternative for fracture repair to satisfy the current unmet need of bone grafts and to alleviate the problems associated with autografts and allografts. The technology offers the possibility to induce new functional bone regeneration using synergistic combination of functional biomaterials (scaffolds), cells, and growth factors. Bone scaffolds are typically made of porous biodegradable materials that provide the mechanical support during repair and regeneration of damaged or diseased bone. Significant progress has been made towards scaffold materials for structural support, desired osteogenesis and angiogenesis abilities. Thanks for innovative scaffolds fabrication technologies, bioresorbable scaffolds with controlled porosity and tailored properties are possible today. Despite the presence of different bone scaffold fabrication methods, pore size, shape and interconnectivity have not yet been fully controlled in most of the methods. Moreover, scaffolds with tailored porosity for specific defects are still difficult to manufacture. Nevertheless, such scaffolds can be designed and fabricated using three dimensional (3D) printing approaches. 3D printing technology, as an advanced tissue scaffold fabrication method, offers the opportunity to produce complex geometries with distinct advantages. The technology has been used for the production of various types of bodily constructs such as blood vessels, vascular networks, bones, cartilages, exoskeletons, eyeglasses, cell cultures, tissues, organs and novel drug delivery devices. This review focuses on 3D printed scaffolds and their application in bone repair and regeneration. In addition, different classes of biomaterials commonly employed for the fabrication of 3D nano scaffolds for bone tissue engineering application so far are briefly discussed.

A Benchmark Side-by-Side Comparison of Two Well-Established Protocols for in vitro Hematopoietic Differentiation From Human Pluripotent Stem Cells.

The generation of transplantable hematopoietic stem cells (HSCs) from human pluripotent stem cells (hPSCs) remains challenging. Current differentiation protocols from hPSCs generate mostly hematopoietic progenitors of the primitive HSC-independent program, and it remains unclear what is the best combination of cytokines and hematopoietic growth factors (HGFs) for obtaining functional hematopoietic cells in vitro. Here, we have used the AND1 and H9 hESC lines and the H9:dual-reporter RUNX1C-GFP-SOX17-Cherry to compare the hematopoietic differentiation in vitro based on the treatment of embryoid bodies (EBs) with the ventral mesoderm inducer BMP4 plus HGFs in the absence (protocol 1) or presence (protocol 2) of stage-specific activation of Wnt/β-catenin and inhibition of Activin/Nodal. Despite a slight trend in favor of protocol 1, no statistically significant differences were observed between protocols at any time point analyzed throughout EB development regarding the frequency of hemogenic endothelial (HE) precursors; CD43+ CD45−, CD45+, and CD45 + CD34 + hematopoietic derivatives; or the output of clonogenic progenitors. Similarly, the kinetics of emergence throughout EB development of both SOX17 + HE and RUNX1C + definitive hematopoiesis was very similar for both protocols. The expression of the early master mesendodermal transcription factors Brachyury, MIXL1, and KDR revealed similar gene expression kinetics prior to the emergence of RUNX1C + definitive hematopoiesis for both protocols. Collectively, the simpler protocol 1 is, at least, as efficient as protocol 2, suggesting that supplementation with additional morphogens/HGFs and modulation of Activin/Nodal and Wnt/β-catenin pathways seem dispensable for in vitro hematopoietic differentiation of hPSCs.

Uterus transplant update: innovative fertility solutions and the widening horizons of bioengineering.

Uterus transplantation (UTx) aimed at restoring fertility for women suffering from uterine factor infertility has been making significant strides over the past years, leading to the first successful outcome of live birth in 2014. Nonetheless, the ethical issues raised by such a procreative option are uniquely complex and multifaceted. UTx presents unique features, and the most significant risks it entails are the multiple surgeries required and the need for immunosuppressive drugs to prevent organ rejection. Post-transplantation immunosuppressive therapy, rejection monitoring, and immune tolerance are all crucial aspects That affect UTx outcomes and ensuing pregnancy success rates. In time, an alternative tool might become clinically available that could solve all those issues: tissue engineering relying on a combination of cells, biomaterials, and growth factors that harness the body's innate ability to regenerate and repair reproductive organs. Mastering such techniques could lead in the medium-long term to the creation of a bioengineered uterus for the purpose of transplantation, based on scaffolds derived from decellularized organs or tissues that can be recellularized by several types of autologous somatic/stem cells, in particular for uterine tissue engineering.

Screening for Growth-Factor Combinations Enabling Synergistic Differentiation of Human MSC to Nucleus Pulposus Cell-Like Cells

Background: Multiple studies have examined the potential of growth factors (GF) to enable mesenchymal stromal cells (MSC) to nucleus pulposus (NP) cell-like cell differentiation. Here we screened a wide range of GF and GF combinations for supporting NP cell-like cell differentiation. Methods: Human MSC were stimulated using 86 different GF combinations of TGF-β1, -2, -3, GDF5, -6, Wnt3a, -5a, -11, and Shh. Differentiation potency was assessed by alcian blue assay and NP cell marker expression (e.g., COL2A1, CD24, etc.). The top four combinations and GDF5/TGF-β1 were further analyzed in 3D pellet cultures, on their ability to similarly induce NP cell differentiation. Results: Almost all 86 GF combinations showed their ability to enhance proteoglycan production in alcian blue assay. Subsequent qPCR analysis revealed TGF-β2/Wnt3a, TGF-β1/Wnt3a, TGF-β1/Wnt3a/GDF6, and Wnt3a/GDF6 as the most potent combinations. Although in pellet cultures, these combinations supported NP marker expression, none showed the ability to significantly induce chondrogenic NP matrix production. Only GDF5/TGF-β1 resulted in chondrogenic pellets with significantly enhanced glycosaminoglycan content. Conclusion: GDF5/TGF-β1 was suggested as an optimal GF combination for MSC to NP cell induction, although further assessment using a 3D and in vivo environment is required. Wnt3a proved promising for monolayer-based NP cell differentiation, although further validation is required.

Clinical evaluation of the treatment of multiple gingival recessions with connective tissue graft or concentrated growth factor using tunnel technique: a randomized controlled clinical trial.

To assess the effectiveness of the combination of tunnel technique (TT) and concentrated growth factor (CGF) for root coverage in treating multiple gingival recessions (GR) and compare with the connective tissue graft (CTG). Forty patients with Miller Class I and II maxillary or mandibular GR were randomly divided into two groups as follows: TT + CTG and TT + CGF. The results at baseline and 6 months were evaluated for the following clinical parameters: complete root coverage (CRC), mean root coverage (MRC), gingival thickness (GT), gingival recession width (RW), gingival recession depth (RD), and keratinized tissue width (KTW). At 6 months, a statistically significant difference was found in RD, RW, MRC, CRC, KTW, and GT compared with the baseline (p < 0.05). MRC was determined 89.52±16.36% in the TT + CTG and 76.60±24.10% in the TT + CGF (p < 0.05). CRC was achieved in 66.7% of the TT + CTG and 47.4% of the TT + CGF (p < 0.05). The increase in KTW and GT was significantly better in the TT + CTG group compared to the TT + CGF (p < 0.05). The study showed that TT + CGF did not improve the results as much as TT + CTG in the treatment of Miller Class I and II GR. However, this finding is not sufficient to advocate the true clinical effects of CGF on GR treatment with TT. CGF could not serve as a direct alternative biomaterial to the gold standard CTG. ClinicalTrials.gov Identification Number: NCT04561947.

Control Delivery of Multiple Growth Factors to Actively Steer Differentiation and Extracellular Matrix Protein Production.

In tissue engineering, biomaterials have been used to steer the host response. This determines the outcome of tissue regeneration, which is modulated by multiple growth factors (GFs). Hence, a sustainable delivery system for GFs is necessary to control tissue regeneration actively. A delivery technique of single and multiple GF combinations, using a layer-by-layer (LBL) procedure to improve tissue remodeling, is developed. TGF-β1, PDGF-ββ, and IGF-1 are incorporated on tailor-made polymeric rods, which could be used as a tool for potential tissue engineering applications, such as templates to induce the formation of in situ tissue engineered blood vessels (TEBVs). Cell response is analyzed in vitro using rat and human dermal fibroblasts for cellular proliferation, fibroblast differentiation, and extracellular matrix (ECM) protein synthesis. Results revealed a higher loading efficiency and control release of GFs incorporated on chloroform and oxygen plasma-activated (COX) rods. Single PDGF-ββ and IGF-1 release, and dual release with TGF-β1 from COX rods, showed higher cell proliferation when compared to COX rods alone. A substantial increase in α-smooth muscle actin (α-SMA) is also observed in GF releasing COX rods, with TGF-β1 COX rods providing the most pronounced differentiation. A significant increase in collagen and elastin synthesis is observed on all GF releasing COX rods compared to control, with COX rods releasing TGF-β1 and IGF-1 providing the highest secretion. TGF-β1 and IGF-1 releasing COX rods induced higher Glycosaminoglycan (GAG)/DNA amounts than the other GF releasing COX rods. As PDGF-ββ and TGF-β1/PDGF-ββ COX rods displayed the highest fibroblast attachment, these rods provided the highest total collagen and elastin production. The attractive results from efficiently incorporating single and multiple GFs on COX rods and their sustainable release to steer cellular behavior suggest a promising route to enrich the formation of in situ engineered tissues.

A Hydrogel Platform that Incorporates Laminin Isoforms for Efficient Presentation of Growth Factors – Neural Growth and Osteogenesis

AbstractLaminins (LMs) are important structural proteins of the extracellular matrix (ECM). The abundance of every LM isoform is tissue‐dependent, suggesting that LM has tissue‐specific roles. LM binds growth factors (GFs), which are powerful cytokines widely used in tissue engineering due to their ability to control stem cell differentiation. Currently, the most commonly used ECM mimetic material in vitro is Matrigel, a matrix of undefined composition containing LM and various GFs, but subjected to batch variability and lacking control of physicochemical properties. Inspired by Matrigel, a new and completely defined hydrogel platform based on hybrid LM‐poly(ethylene glycol) (PEG) hydrogels with controllable stiffness (1–25 kPa) and degradability is proposed. Different LM isoforms are used to bind and efficiently display GFs (here, bone morphogenetic protein (BMP‐2) and beta‐nerve growth factor (β‐NGF)), enabling their solid‐phase presentation at ultralow doses to specifically target a range of tissues. The potential of this platform to trigger stem cell differentiation toward osteogenic lineages and stimulate neural cells growth in 3D, is demonstrated. These hydrogels enable 3D, synthetic, defined composition, and reproducible cell culture microenvironments reflecting the complexity of the native ECM, where GFs in combination with LM isoforms yield the full diversity of cellular processes.

Nanofibrous hyaluronic acid scaffolds delivering TGF-β3 and SDF-1α for articular cartilage repair in a large animal model

Focal cartilage injuries have poor intrinsic healing potential and often progress to osteoarthritis, a costly disease affecting almost a third of adults in the United States. To treat these patients, cartilage repair therapies often use cell-seeded scaffolds, which are limited by donor site morbidity, high costs, and poor efficacy. To address these limitations, we developed an electrospun cell-free fibrous hyaluronic acid (HA) scaffold that delivers factors specifically designed to enhance cartilage repair: Stromal Cell-Derived Factor-1α (SDF-1α; SDF) to increase the recruitment and infiltration of mesenchymal stem cells (MSCs) and Transforming Growth Factor-β3 (TGF-β3; TGF) to enhance cartilage tissue formation. Scaffolds were characterized in vitro and then deployed in a large animal model of full-thickness cartilage defect repair. The bioactivity of both factors was verified in vitro, with both SDF and TGF increasing cell migration, and TGF increasing matrix formation by MSCs. In vivo, however, scaffolds releasing SDF resulted in an inferior cartilage healing response (lower mechanics, lower ICRS II histology score) compared to scaffolds releasing TGF alone. These results highlight the importance of translation into large animal models to appropriately screen scaffolds and therapies, and will guide investigators towards alternative growth factor combinations. Statement of significanceThis study addresses an area of orthopaedic medicine in which treatment options are limited and new biomaterials stand to improve patient outcomes. Those suffering from articular cartilage injuries are often destined to have early onset osteoarthritis. We have created a cell-free nanofibrous hyaluronic acid (HA) scaffold that delivers factors specifically designed to enhance cartilage repair: Stromal Cell-Derived Factor-1α (SDF-1α; SDF) to increase the recruitment and infiltration of mesenchymal stem cells (MSCs) and Transforming Growth Factor-β3 (TGF-β3; TGF) to enhance cartilage tissue formation. To our knowledge, this study is the first to evaluate such a bioactive scaffold in a large animal model and demonstrates the capacity for dual growth factor release.

The Effect of Alendronate on Osteoclastogenesis in Different Combinations of M-CSF and RANKL Growth Factors.

Bisphosphonates (BPs) are compounds resembling the pyrophosphate structure. BPs bind the mineral component of bones. During the bone resorption by osteoclasts, nitrogen-containing BPs are released and internalized, causing an inhibition of the mevalonate pathway. As a consequence, osteoclasts are unable to execute their function. Alendronate (ALN) is a bisphosphonate used to treat osteoporosis. Its administration could be associated with adverse effects. The purpose of this study is to evaluate four different ALN concentrations, ranging from 10−6 to 10−10 M, in the presence of different combinations of M-CSF and RANKL, to find out the effect of low ALN concentrations on osteoclastogenesis using rat and human peripheral blood mononuclear cells. The cytotoxic effect of ALN was evaluated based on metabolic activity and DNA concentration measurement. The alteration in osteoclastogenesis was assessed by the activity of carbonic anhydrase II (CA II), tartrate-resistant acid phosphatase staining, and actin ring formation. The ALN concentration of 10−6 M was cytotoxic. Low ALN concentrations of 10−8 and 10−10 M promoted proliferation, osteoclast-like cell formation, and CA II activity. The results indicated the induction of osteoclastogenesis with low ALN concentrations. However, when high doses of ALN were administered, their cytotoxic effect was demonstrated.

Combinatorial mechanical gradation and growth factor biopatterning strategy for spatially controlled bone-tendon-like cell differentiation and tissue formation

Engineering scaffolds to augment the repair of hard-to-soft multitissue musculoskeletal tissue units, such as bone-tendon, to simultaneously support tissue healing and functional movement has had limited success. Overcoming this challenge will require not only precise spatial control of bone- and tendon-like biomechanical properties, but also consideration of the resultant biomechanical cues, as well as the embedded biochemical cues imparted by these scaffolds. Here, we report on the effects of a spatially engineered combination of stiffness and growth factor (GF) cues to control bone-tendon-like differentiation in vitro and tissue formation in vivo. This was achieved using mechanically graded, bone- and tendon-like QHM polyurethane (QHM: Q: Quadrol; H: hexamethylene diisocyanate; M: methacrylic anhydride) scaffolds selectively biopatterned with osteogenic bone morphogenetic protein-2 (BMP-2) and tenogenic fibroblast growth factor-2 (FGF-2). First, material characterization, including porosity, surface roughness, contact angle, and microindentation measurements, was performed. Second, in vitro studies demonstrated that increased material stiffness promoted GF-mediated osteoblast differentiation and reduced tenocyte differentiation. Sustained GF exposure masked this stiffness effect. Third, in vivo studies involving subcutaneous implantation of mechanically graded and biochemically patterned QHM scaffolds (composed of these bone- and tendon-promoting GFs biopatterned on biphasic bone and tendon biomechanically mimicking regions) in mice demonstrated spatial control of bone- and tendon-like tissue formation. Altogether, these data provide new insights for future engineering of scaffolds to augment hard-to-soft multitissue repair.

A Review of Tissue‐Engineered Cartilage Utilizing Fibrin and Its Composite

Suitable alternatives are made for damaged or diseased organs and tissues in tissue engineering by combining cellular and molecular biology with materials and mechanical engineering. Fibrin is a critical blood component responsible for homeostasis, used extensively as a biopolymer scaffold in tissue engineering. This study summarizes the latest developments in organ and tissue regeneration using fibrin as a scaffold material. The combination of active peptides and growth factors through a heparin-bound delivery system improves fibrin function as a scaffold. Besides, the development of fibrin precursors as recombinant proteins solves multiple or single donor fibrin adhesives. Its composite allows biomolecules to be combined with fibrin and can significantly enhance fibrin efficacy in cartilage tissue engineering applications.

An efficacy comparison of combination of different anti-vascular endothelial growth factors and photodynamic therapy in patients with pachychoroid neovasculopathy.

To evaluate anatomical and visual outcomes in patients who received intravitreal anti-vascular endothelial growth factor (VEGF) agents in combination with full-dose photodynamic therapy (PDT) on eyes with choroidal neovascularization (CNV) secondary to naive pachychoroid neovasculopathy (PNV). Medical records on 19 eyes of 19 patients whom intravitreal bevacizumab (IVB), intravitreal ranibizumab (IVR), and intravitreal aflibercept (IVA) injections were administered for CNV caused by PNV were enrolled into the study. The central macular thickness (CMT), best-corrected visual acuity (BCVA), and subfoveal choroidal thickness (SFCT) were recorded at the baseline, months 1, 3, 6, 12, and final control visit following treatment. The age average was 53.84 ± 5.23years (range, 46-62years), and mean follow-up time was 33.42 ± 9.43months (range, 16-49months). The change in BCVA was found statistically significant in the IVA group only during follow-up visits (p = 0.007). Although there was no statistically significant change in CMT following IVR (360.60 ± 75.64-252 ± 75.04µm) (p = 0.077), significant changes were observed in IVB (397.14 ± 122.59-275.28 ± 63.82µm) (p = 0.004) and IVA (385.85 ± 43.82-244.42 ± 51.57µm) (p = 0.005) between the baseline and the final visit. SFCT significantly decreased following both IVR and IVA treatments (p = 0.016, p = 0.039, respectively). In consideration of the number of injections, significantly fewer injections were needed in the IVA group than the others (p = 0.018). Anti-VEGF agents with full-dose PDT were well tolerated for the first 3months and were highly effective treatment option in order to naive PNV patients. However, in long-term follow-ups, the effectiveness of IVA was superior to other anti-VEGFs.

Influence of the Mechanical Environment on the Regeneration of Osteochondral Defects

Articular cartilage is a highly specialised connective tissue of diarthrodial joints which provides a smooth, lubricated surface for joint articulation and plays a crucial role in the transmission of loads. In vivo cartilage is subjected to mechanical stimuli that are essential for cartilage development and the maintenance of a chondrocytic phenotype. Cartilage damage caused by traumatic injuries, ageing, or degradative diseases leads to impaired loading resistance and progressive degeneration of both the articular cartilage and the underlying subchondral bone. Since the tissue has limited self-repairing capacity due its avascular nature, restoration of its mechanical properties is still a major challenge. Tissue engineering techniques have the potential to heal osteochondral defects using a combination of stem cells, growth factors, and biomaterials that could produce a biomechanically functional tissue, representative of native hyaline cartilage. However, current clinical approaches fail to repair full-thickness defects that include the underlying subchondral bone. Moreover, when tested in vivo, current tissue-engineered grafts show limited capacity to regenerate the damaged tissue due to poor integration with host cartilage and the failure to retain structural integrity after insertion, resulting in reduced mechanical function. The aim of this review is to examine the optimal characteristics of osteochondral scaffolds. Additionally, an overview on the latest biomaterials potentially able to replicate the natural mechanical environment of articular cartilage and their role in maintaining mechanical cues to drive chondrogenesis will be detailed, as well as the overall mechanical performance of grafts engineered using different technologies.

Endothelial cell-type-specific molecular requirements for angiogenesis drive fenestrated vessel development in the brain.

Vascular endothelial cells (vECs) in the brain exhibit structural and functional heterogeneity. Fenestrated, permeable brain vasculature mediates neuroendocrine function, body-fluid regulation, and neural immune responses; however, its vascular formation remains poorly understood. Here, we show that specific combinations of vascular endothelial growth factors (Vegfs) are required to selectively drive fenestrated vessel formation in the zebrafish myelencephalic choroid plexus (mCP). We found that the combined, but not individual, loss of Vegfab, Vegfc, and Vegfd causes severely impaired mCP vascularization with little effect on neighboring non-fenestrated brain vessel formation, demonstrating fenestrated-vEC-specific angiogenic requirements. This Vegfs-mediated vessel-selective patterning also involves Ccbe1. Expression analyses, cell-type-specific ablation, and paracrine activity-deficient vegfc mutant characterization suggest that vEC-autonomous Vegfc and meningeal fibroblast-derived Vegfab and Vegfd are critical for mCP vascularization. These results define molecular cues and cell types critical for directing fenestrated CP vascularization and indicate that vECs' distinct molecular requirements for angiogenesis underlie brain vessel heterogeneity.

Bone regeneration in critical-size calvarial defect using functional biocompatible osteoinductive herbal scaffolds and human umbilical cord Wharton’s Jelly-derived mesenchymal stem cells

Critical size calvarial bone defects and their repair is the major challenge in orthopaedic surgery. Bone tissue engineering using varied combinations of scaffolds, stem cells, and growth factors is an emerging choice of treatment for variety of bone defects. Present study aimed to compare and evaluate the potential of poly ε-caprolactone (PCL), PCL- graphene oxide (GO), PCL-GO-Cissus quadrangularis (CQ), and human umbilical cord-derived mesenchymal stem cells (hUCMSCs) seeded PCL (PCL- hUCMSCs), PCL-GO-CQ-hUCMSCs scaffolds to heal critical size calvarial bone defect in the rat models. Healthy adult Wister female rats (N = 30) with average body weight of 350 ± 30 g were divided to 6 groups with five animals in each group. Single critical size calvarial defects of 8 mm were created in the skull of each rat and same were treated with respective scaffolds. The outcome of the treatments was evaluated at 6 weeks and 12 weeks in terms of weight, haematological parameters and biochemical parameters for biocompatibility. New bone regeneration/healing was analysed using digital radiography and micro-computed tomography. Quality of bone formed was analysed by bone mineral density. Histological analysis of the bone tissues was performed using an optical microscope. All the scaffolds were biocompatible and there was no adverse effect of these scaffolds on animals. Higher bone regeneration was observed after 12 weeks of transplantation than 6 weeks. However, PCL-GO-CQ-hUCMSCs scaffolds exhibited highest bone regeneration 12 weeks post-transplantation. The unique combination of PCL-GO-CQ-hUCMSCs scaffold proved to be beneficial in bone regeneration by aiding nearly complete healing of defect site. Further studies with PCL-GO-CQ-hUCMSCs could pave the way for human clinical trials.

Biophysical model for high-throughput tumor and epithelial cell co-culture in complex biochemical microenvironments

The in vivo tumor microenvironment is a complex niche that includes heterogeneous physical structures, unique biochemical gradients and multiple cell interactions. Its high-fidelity in vitro reconstruction is of fundamental importance to improve current understandings of cell behavior, efficacy predictions and drug safety. In this study, we have developed a high-throughput biochip with hundreds of composite extracellular matrix (ECM) microchambers to co-culture invasive breast cancer cells (MDA-MB-231-RFP) and normal breast epithelial cells (MCF-10A-GFP). The composite ECM is composed of type I collagen and Matrigel which provides a heterogeneous microenvironment that is similar to that of in vivo cell growth. Additionally, the growth factors and drug gradients that involve human epidermal growth factor (EGF), discoidin domain receptor 1 (DDR1) inhibitor 7rh and matrix metalloproteinase inhibitor batimastat allow for the mimicking of the complex in vivo biochemical microenvironment to investigate their effect on the spatial-temporal dynamics of cell growth. Our results demonstrate that the MDA-MB-231-RFP cells and MCF-10A-GFP cells exhibit different spatial proliferation behaviors under the combination of growth factors and drugs. Basing on the experimental data, we have also developed a cellular automata (CA) model that incorporated drug diffusion to describe the experimental phenomenon, as well as employed Shannon entropy (SE) to explore the effect of the drug diffusion coefficient on the spatial-temporal dynamics of cell growth. The results indicate that the uniform cell growth is related to the drug diffusion coefficient, which reveals that the pore size of the ECM plays a key role in the formation of complex biochemical gradients. Therefore, our integrated, biomimetic and high-throughput co-culture platforms, as well as the computational model can be used as an effective tool for investigating cancer pathogenesis and drug development.

GDF-5 variant loading on composite scaffolds promotes spinal fusion through coupling of osteogenesis and angiogenesis: A preclinical study in rhesus monkeys

Although bone morphogenetic protein-2 (BMP-2) is widely used for spinal fusion, some concerns cannot be ignored. The combination of growth factor with composite scaffolds represent a promising approach to promote bone regeneration and spinal fusion. Recent studies have demonstrated that the growth differentiation factor-5 (GDF-5) variant BB-1, combining the osteogenic activity of BMP-2 with the angiogenic features of GDF-5, enhanced bone regeneration during long-bone healing in lower-order animals. The study aimed to investigate the efficacy and safety of BB-1 loading on composite scaffolds on spinal fusion in nonhuman primates. Six healthy rhesus monkeys were used to establish a clinically relevant two-segment spinal fusion model. Blank scaffolds or BB-1-loaded scaffolds were implanted into each animal and distributed in a blinded way. Imageological and histological examinations as well as bone histomorphometry were performed after euthanization at 6 months post-operation. BB-1 led to a higher spinal fusion rate (5/6) compared to the negative control (1/6). Mechanically, BB-1 stimulated bone formation and vessel formation. Furthermore, we found that BB-1 increased the density of H-type vessels in the newly formed bone tissues for the first time. Moreover, 500 ​μg BB-1 triggered no local inflammation response in each spine segment and no systematic toxicity in liver and kidney. These results suggest that BB-1 promotes spinal fusion in rhesus monkeys by coupling of angiogenesis and osteogenesis and that local usage of 500 ​μg BB-1 should be effective and safe, facilitating translation of BB-1 from bench to bedside.