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Scar formation can lead to glaucoma filtration surgery (GFS) failure, wherein transforming growth factor (TGF)-β is the core regulator. To reducing scar formation, this paper presents our study on the design of hydrogels to deactivate TGF-β1. We hypothesized that excess TGF-β1 can be removed from aqueous humor through the addition of oxidized hyaluronic acid (O-HA) hydrogels that are seeded with decorin (O-HA ​+ ​D). Immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were performed to demonstrate the adsorption properties of O-HA ​+ ​D hydrogel, thus reducing the TGF-β1 concentration in aqueous humor. In the light that collagen contraction in human Tenon's capsule fibroblasts (HTFs) and the angiogenesis of human umbilical vein endothelial cells (HUVECs) can be activated by TGF-β1 and β2, we performed the quantitative analysis of polymerase chain reaction to determine the effect of O-HA ​+ ​D on the type I collagen, fibronectin, and angiogenesis. Our results illustrate that O-HA ​+ ​D can inhibit the increase of α-SMA expression in HTF induced by TGF-β1 and that O-HA ​+ ​D can inhibit the production of collagen I and fibronectin in HTF treated with TGF-β1. Furthermore, we performed in vivo studies by employing a rabbit model, where rabbits were treated with hydrogels post GFS. Our results demonstrate that, as compared with other groups, the rabbits treated with O-HA ​+ ​D had the greatest reduction in inflammatory cells with reduced level of collagen in wounds. Taken together, the present study paves the way toward the treatment of post-glaucoma fibrosis following surgery.

Neuroinflammation is one of the major processes that trigger neuropathological amyloid-β (Aβ) deposition and contribute to Alzheimer’s disease (AD) progression. Naked mole rats, which are the longest living rodents and exhibit negligible senescence, have a special brain microenvironment characterized by high-molecular-mass hyaluronan (HMM-HA) and high levels of neuregulin 1 (NRG1), which are related to resistance to neuroinflammation and Aβ deposition, leading to protection from AD. Thus, mimicking the unique brain microenvironment of the naked mole rat as a strategy for AD treatment is of critical interest. Here, naked mole rat HMM-HA and NRG1 were used to establish an injectable neuroinflammation-responsive triglycerol monostearate (TM)-HA-NRG1 hydrogel to alter the brain microenvironment in the early to late stages of AD. Intracerebroventricular (ICV) delivery of the hydrogel resulted in significant mitigation of Aβ plaque formation and complement C1q deposition in the hippocampus. Interestingly, we found that C1q deposition on pericytes was probably associated with capillary dysfunction. Furthermore, continuous intervention obviously reduced C1q deposition on pericytes and improved the oxygen supply to the brain. Importantly, in 16-month-old AD mice, cognitive decline was significantly ameliorated after TM-HA-NRG1 hydrogel treatment. Thus, the work reported here provides a potential early intervention strategy for retarding later AD progression.

Photodynamic therapy (PDT) is limited by its penetration depth because of the selection of photosensitizer and light source. In this study, Ce-doped TiO 2 (TiO 2 :Ce) was synthesized by a modified sol-gel method to act as a photosensitizer activated by low-dose X-rays, less harmful than ionizing radiation, to generate intracellular reactive oxygen species (ROS). The A549 cell line was used as the in vitro and in vivo model to evaluate the efficacy of X-ray-irradiated TiO 2 :Ce to induce cell death. The cell viability significantly decreased with TiO 2 :Ce exposure under low-dose X-ray irradiation. An LDH assay showed that intracellular TiO 2 :Ce under X-ray irradiation was cytotoxic to A549 cancer cells. TiO 2 :Ce produced significant ROS under low-dose X-ray irradiation and promoted apoptosis/necrosis of A549 cancer cells. TiO 2 :Ce can enhance the efficacy of X-ray-induced PDT, and tumor growth was inhibited in vivo . The mechanisms underlying ROS generation by TiO 2 :Ce activated by X-ray irradiation to induce cell toxicity, thereby inhibiting tumor growth, is discussed.

Neural progenitor cell (NPC) replacement therapy is a promising treatment for neurodegenerative disorders including Parkinson's disease (PD). It requires a controlled directional migration and integration of NPCs, for example dopaminergic (DA) progenitor cells, into the damaged host brain tissue. There is, however, only limited understanding of how to regulate the directed migration of NPCs to the diseased or damaged brain tissues for repair and regeneration. The aims of this study are to explore the possibility of using a physiological level of electrical stimulation to regulate the directed migration of ventral midbrain NPCs (NPCs(vm)), and to investigate their potential regulation via GSK3β and associated downstream effectors. We tested the effects of direct-current (DC) electric fields (EFs) on the migration behavior of the NPCs(vm). A DC EF induced directional cell migration toward the cathode, namely electrotaxis. Reversal of the EF polarity triggered a sharp reversal of the NPC(vm) electrotaxis. The electrotactic response was both time and EF voltage dependent. Pharmacologically inhibiting the canonical Wnt/GSK3β pathway significantly reduced the electrotactic response of NPCs(vm), which is associated with the down-regulation of GSK3β phosphorylation, β-catenin activation and CLASP2 expression. This was further proved by RNA interference of GSK3β, which also showed a significantly reduced electrotactic response in association with reduced β-catenin activation and CLASP2 expression. In comparison, RNA interference of β-catenin slightly reduced electrotactic response and CLASP2 expression. Both pharmacological inhibition of Wnt/GSK3β and RNA interference of GSK3β/β-catenin clearly reduced the asymmetric redistribution of CLASP2 and its co-localization with α-tubulin. These results suggest that Wnt/GSK3β signaling contributes to the electrotactic response of NPCs(vm) through the coordination of GSK3β phosphorylation, β-catenin activation, CLASP2 expression and asymmetric redistribution to the leading edge of the migrating cells.

To overcome bad prognosis of patients with heart failure and the lack of organ donors, cardiac tissue engineering has developed as a biomimetic approach to repair, replace, and regenerate the damaged cardiac tissue. During the past decade years, researchers are devoted to find different natural and/or synthetic materials that can build appropriate physical structures to contain and organize implanted cells. In this study, we present a new method for primary neonatal rat cardiomyocytes culture in vitro using alginate/collagen/chitosan hydrogel. To investigate the feasibility of this material as scaffold for cardiac myocytes, neonatal rat ventricular myocytes were isolated and encapsulated in alginate-based beads cross-linked with calcium ion. The growth of cells was evaluated by staining with α-Sarcomeric actin (α-SCA) and Troponin T type 2 (TNNT2), and the viability of cardiomyocytes was studied in vitro by assessing the expression levels of several cardiac ion channels, including CACNL1A1, Connexin 43 and SCN5A. The results showed a significant increase in cardiac myocytes number, and the expression levels of CACNL1A1, Connexin 43 (Cx43) were up-regulated significantly except SCN5A, as compared with two-dimensional cultures. Moreover, extracellular matrix produced by the seeded cells themselves was observed by staining with fibronectin. Taken together, these findings indicate that this alginate/collagen/chitosan hydrogel bead is suitable for supporting the growth and retaining the morphologic and electrophysiologic characteristics of primary cultured rat cardiac muscle cells.

This study investigated intracellular oxidative stress and its underlying mechanisms in a rotary cell culture system used to achieve a simulated microgravity (SMG) environment. Experiments were conducted with human breast cancer cell lines MCF-7 (an estrogen receptor (ER) α positive cell line) and MDA-MB-231 (an ERα negative cell line) encapsulated in alginate/collagen carriers. After 48 h, SMG led to oxidative stress and DNA damage in the MDA-MB-231 cells but a significant increase in mitochondrial activity and minimal DNA damage in the MCF-7 cells. The activity of superoxide dismutase (SOD) significantly increased in the MCF-7 cells and decreased in MDA-MB-231 cells in the SMG environment compared with a standard gravity control. Moreover, SMG promoted expression of ERα and protein kinase C (PKC) epsilon in MCF-7 cells treated with PKC inhibitor Go6983. Overall, exposure to SMG increased mitochondrial activity in ERα positive cells but induced cellular oxidative damage in ERα negative cells. Thus, ERα may play an important role in protecting cells from oxidative stress damage under simulated microgravity.

Matrix metalloproteinases (MMPs) are enzymes with specificity towards extracellular matrix (ECM) components. MMPs, especially MMP-9, have been shown to degrade components of the basal lamina and disrupt the blood-brain barrier (BBB) and thus, contribute to neuroinflammation. In the present study we examined the role of MMP-9 in the foreign body response in the brain. Millipore filters of mixed cellulose ester were implanted into the brain cortex of wild type and MMP-9-null mice for a period of 2 d to 8 wks and the response was analyzed by histology and immunohistochemistry. We observed enhanced and prolonged neuroinflammation in MMP-9-null mice, evidenced by persistence of neutrophils, macrophages/microglia, and reactive astrocytes up to 8 wks post-implantation. In addition, blood vessel density around implants was increased in MMP-9-null mice and detection of mouse serum albumin (MSA) indicated that vessels were leaky. Immunohistochemical and western blot analyses indicated that this defect was associated with the absence of tight junction proteins zonula occludens-1 (ZO-1) and ZO-2 from vessels in proximity to implants. Analysis of brain sections and brain protein extracts revealed that the levels of the pro-inflammatory cytokine interleukin-1beta (IL-1beta), which is a substrate for MMP-9, were significantly higher in MMP-9-null mice at 8wks post-implantation. Collectively, our studies suggest that increased levels of IL-1beta and the delayed repair of BBB are associated with prolongation of the FBR in MMP-9-null mice.

The aim of this study is to test the adhesion of human gingival fibroblasts (HGFs) and epithelial cells (HGEs) to titanium surface by RGD grafting for dental implant, and to obtain an effective perimucosal seal of soft tissue to the implant. RGD peptides were covalently attached to the titanium surface by CDI activation method to improve the adhesion of gingival cells to the titanium dental implants. HGFs and HGEs were inoculated on commercially pure (CP) titanium and RGD-grafted titanium. The number of attached and proliferated cells was quantified by morphometric analysis using immunofluorescence. The results showed that the bioactive peptide RGD was grafted on CP titanium by CDI activation method. The RGD grafting exhibited that the number of attached and proliferated fibroblasts and epithelial cells were higher than that on CP titanium. The RGD-grafting is advantageous to gingival cells adherence to the surface of titanium implant.

The barrier material of Fe 3+ cross-linked pure carboxy-methylcellulose (CMC) has been evaluated in the prevention of postoperative adhesion formation in the injured Achilles tendon using rabbit model. Adhesion formation between the wounds has been assessed and quantitated 14 days after the surgery of 30 rabbits, each of which had two test sites. The use of a Fe 3+ cross-linked carboxy-methylcellulose (CMC) barrier material has effectively reduced the postoperative adhesion formation with 88% fewer adhesions observed in these models without any adverse impact on the tissues, which implies great potential in preventing the postoperative adhesions and deserves clinical evaluation.

Nogo-66 and NgR are important receptors inhibiting neuronal regeneration and therefore are targets for treating CNS injury. Antagonists of this receptor including blocking antibodies are potential therapeutic agents for CNS axonal injuries such as spinal cord and brain trauma. A new antibody (IgG) releasing system has been developed by covalently attaching IgG to the biodegradable hyaluronic acid (HA) hydrogel via the hydrolytically unstable hydrazone linkage, aiming to deliver the antibody of CNS regeneration inhibitors to the injured brain. In this paper we describe the synthesis, physico-chemical characteristics and test results of biological activity of antibody released from hyluronic acid hydrogel. To form the conjugates the antibody is attached to the polymer backbone using a condensation reaction between aldehyde group of the antibody and hydrazide group of the HA hydrogel. Furthermore, pH sensitive linkage-hydrozone has been formed between hydrogel and antibody. The amount of conjugated antibodies can reach 135 microg antibody/mg hydrogel in the dry state. At low pH, the antibodies released quite fast. However, the antibodies released much slower in neutral and alkaline environment. The bioactivity of antibody released from hydrogel was retained as demonstrated by indirect immunofluorescence technique.