Reactive oxygen species-mediated endoplasmic reticulum stress contributes to osteocyte death induced by orthodontic compressive force.

During orthodontic tooth movement (OTM), osteocytes, the most mechanosensitive cells in alveolar bone, suffer the heavy orthodontic force and initiate alveolar bone resorption on the compression side. However, the inherent mechanisms of compressive force-induced osteocyte death are not fully understood. In this study, we established an OTM model on Sprague-Dawley rats by inserting coil springs to investigate osteocyte damage on the compression side of alveolar bone. We then applied compressive force on the MLO-Y4 osteocyte-like cell line in vitro to explore whether the reactive oxygen species (ROS)-mediated endoplasmic reticulum stress (ERS) pathway is involved in compressive force-induced osteocyte death. We found that the orthodontic force caused apparent alveolar bone loss, osteocyte death, and elevated serum sclerostin and receptor activator of NF-κB ligand (RANKL) levels in rats. In vitro, compressive force inhibited cell viability but increased the LDH leakage and loss of mitochondrial membrane potential in MLO-Y4 cells. Simultaneously, it activated protein kinase RNA-like endoplasmic reticulum kinase (PERK), eukaryotic translation initiation factor 2 (eIF2α), and their downstream pro-apoptotic ERS signaling proteins and caused significant osteocyte apoptosis, which can be blocked by ERS inhibitor salubrinal. Moreover, the compressive force elevated intracellular ROS levels, while the ROS scavenger N-acetyl-L-cysteine (NAC) alleviated ERS and apoptosis in loaded osteocytes. These results suggest that the orthodontic compressive force induced osteocyte apoptosis via the ROS-mediated ERS pathway. This study first proposes the ERS pathway as a new potential pathway for regulating the rate of OTM based on osteocyte death. RESEARCH HIGHLIGHTS: The orthodontic force increases osteocyte death in rat alveolar bone. The compressive force causes osteocyte apoptosis by the endoplasmic reticulum stress (ERS) pathway in vitro. The ROS scavenger NAC blocked compressive force-induced ERS and osteocyte apoptosis.

Bisphenol S exposure promotes cell apoptosis and mitophagy in murine osteocytes by regulating mtROS signaling.

Bisphenol S (BPS), a safer alternative to bisphenol A, is commonly used as a plasticizer to manufacture various food-packaging materials. The accumulated BPS inhibits osteoblastic bone formation and promotes osteoclastogenesis, thereby accelerating remarkable bone destruction, but it is unclear whether BPS affects osteocytes, comprising over 95% of all bone cells. This study aimed to investigate the biological effect of BPS on osteocytes in vitro, as well as the detailed mechanism. Results showed that BPS (200, 400 µmol/L) exposure caused dose-dependently cell death of osteocytes MLO-Y4, and increased cell apoptosis. BPS induced loss of mitochondrial membrane potential (MMP) and mitochondria impairment. Furthermore, BPS upregulated expressions of mitophagy-related proteins including microtubule-associated protein light chain 3 (LC-3) II and PTEN-induced putative kinase (PINK) 1, accompanied by elevation of autophagy flux and the accumulation of acidic vacuoles; whereas p62 level was downregulated after BPS treatment. Additionally, BPS triggered the production of intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS), while it decreased expression levels of nuclear factor E2-related factor 2 (Nrf2) and quinone oxidoreductase 1 (NQO1). The specific mtROS scavenger MitoTEMPO reversed cell apoptosis and mitophagy, suggesting that mtROS contributes to BPS exposure-induced apoptosis and mitophagy in MLO-Y4 cells. Our data first provide novel evidence that apoptosis and mitophagy as cellular mechanisms for the toxic effect of BPS on osteocytes, thereby helping our understanding of the potential role of osteocytes in the adverse effect of BPS and its analogs on bone growth, and supporting strategies targeting bone destruction caused by BPS.

Endothelial cells regulate astrocyte to neural progenitor cell trans-differentiation in a mouse model of stroke.

The concept of the neurovascular unit emphasizes the importance of cell-cell signaling between neural, glial, and vascular compartments. In neurogenesis, for example, brain endothelial cells play a key role by supplying trophic support to neural progenitors. Here, we describe a surprising phenomenon where brain endothelial cells may release trans-differentiation signals that convert astrocytes into neural progenitor cells in male mice after stroke. After oxygen-glucose deprivation, brain endothelial cells release microvesicles containing pro-neural factor Ascl1 that enter into astrocytes to induce their trans-differentiation into neural progenitors. In mouse models of focal cerebral ischemia, Ascl1 is upregulated in endothelium prior to astrocytic conversion into neural progenitor cells. Injecting brain endothelial-derived microvesicles amplifies the process of astrocyte trans-differentiation. Endothelial-specific overexpression of Ascl1 increases the local conversion of astrocytes into neural progenitors and improves behavioral recovery. Our findings describe an unexpected vascular-regulated mechanism of neuroplasticity that may open up therapeutic opportunities for improving outcomes after stroke.

Formation of Double Stranded RNA Provokes Smooth Muscle Contractions and Structural Modifications in Bladder Ischemia.

Purpose: Growing evidence suggests that ischemia provokes detrusor overactivity and degenerative responses in the bladder. Underlying mechanisms appear to involve modification of smooth muscle contractile rudiments by hypoxia, redox, cellular stress and cell survival signaling. Downstream pathways of cellular stress and stress response molecules eliciting bladder dysfunction in ischemia remain largely elusive. Our goal was to define the role of double stranded RNA (dsRNA), a stress response molecule provoked by redox, in ischemia mediated bladder dysfunction. Methods: A rat model of pelvic ischemia along with a cell culture hypoxia model were used to investigate the expression levels, functional consequences, structural aspects, and regulatory mechanisms of dsRNA in the bladder. Gene and protein expression were examined by reverse transcription polymerase chain reaction (RT-PCR), dot blot, and Western blotting, respectively. Tissue structure and function were assessed using histological staining and organ bath. Regulatory mechanisms were analyzed in cultured bladder smooth muscle cells. Results: The data presented here provide the first evidence of the formation of dsRNA in the overactive bladder. dsRNA is a cellular stress response molecule that sensitizes smooth muscle and regulates inflammatory and degenerative rejoinders. Our data suggest that the production of dsRNA in the bladder is provoked by ischemia. Formation of dsRNA appears to augment bladder smooth muscle contractions and provoke fibrotic and apoptotic responses. Downstream actions of dsRNA in the bladder may involve upregulation of dsRNA-activated protein kinase R (PKR) and caspase-3, the executioner of apoptosis. Conclusion: Activation of dsRNA/PKR pathway may play a role in sensitization of bladder smooth muscle cells to contractile stimuli, whereas dsRNA and caspase-3 crosstalk appear to modulate cellular stress and instigate degenerative responses in bladder ischemia. These observations suggest the role of dsRNA in bladder dysfunction and may open new perspectives to overcome overactive smooth muscle contractions and structural damage in the bladder.

Platelet-Rich Plasma Lysate-Incorporating Gelatin Hydrogel as a Scaffold for Bone Reconstruction.

In implant dentistry, large vertical and horizontal alveolar ridge deficiencies in mandibular and maxillary bone are challenges that clinicians continue to face. One of the limitations of porous blocks for reconstruction of bone in large defects in the oral cavity, and in the musculoskeletal system, is that fibrin clot does not adequately fill the interior pores and does not persist long enough to accommodate cell migration into the center of the block. The objective of our work was to develop a gelatin-based gel incorporating platelet-rich plasma (PRP) lysate, to mimic the role that a blood clot would normally play to attract and accommodate the migration of host osteoprogenitor and endothelial cells into the scaffold, thereby facilitating bone reconstruction. A conjugate of gelatin (Gtn) and hydroxyphenyl propionic acid (HPA), an amino-acid-like molecule, was commended for this application because of its ability to undergo enzyme-mediated covalent cross-linking to form a hydrogel in vivo, after being injected as a liquid. The initiation and propagation of cross-linking were under the control of horseradish peroxidase and hydrogen peroxide, respectively. The objectives of this in vitro study were directed toward evaluating: (1) the migration of rat mesenchymal stem cells (MSCs) into Gtn-HPA gel under the influence of rat PRP lysate or recombinant platelet-derived growth factor (PDGF)-BB incorporated into the gel; (2) the differentiation of MSCs, incorporated into the gel, into osteogenic cells under the influence of PRP lysate and PDGF-BB; and (3) the release kinetics of PDGF-BB from gels incorporating two formulations of PRP lysate and recombinant PDGF-BB. Results: The number of MSCs migrating into the hydrogel was significantly (3-fold) higher in the hydrogel group incorporating PRP lysate compared to the PDGF-BB and the blank gel control groups. For the differentiation/osteogenesis assay, the osteocalcin-positive cell area percentage was significantly higher in both the gel/PRP and gel/PDGF-BB groups, compared to the two control groups: cells in the blank gels grown in cell expansion medium and in osteogenic medium. Results of the ELISA release assay indicated that Gtn-HPA acted as an effective delivery vehicle for the sustained release of PDGF-BB from two different PRP lysate batches, with about 60% of the original PDGF-BB amount in the two groups remaining in the gel at 28 days. Conclusions: Gtn-HPA accommodates MSC migration. PRP-lysate-incorporating hydrogels chemoattract increased MSC migration into the Gtn-HPA compared to the blank gel. PRP-lysate- and the PDGF-BB-incorporating gels stimulate osteogenic differentiation of the MSCs. The release of the growth factors from Gtn-HPA containing PRP lysate can extend over the period of time (weeks) necessary for bone reconstruction. The findings demonstrate that Gtn-HPA can serve as both a scaffold for cell migration and a delivery vehicle that allows sustained and controlled release of the incorporated therapeutic agent over extended periods of time. These findings commend Gtn-HPA incorporating PRP lysate for infusion into porous calcium phosphate blocks for vertical and horizontal ridge reconstruction, and for other musculoskeletal applications.

Tricalcium phosphate particles promote pyroptotic death of calvaria osteocytes through the ROS/NLRP3/Caspase-1 signaling axis in amouse osteolysis model.

Wear particles-induced inflammatory osteolysis, a major factor of aseptic loosening affects the long-term survival of orthopedic prostheses. Increasing observations have demonstrated that osteocytes, making up over 95% of all the bone cells, is involved in wear particle-induced periprosthetic osteolysis, but its mechanism remains unclear. In the present study, we embedded micro-sized tricalcium phosphate (TCP) particles (30 mg) under the periosteum around the middle suture of the mouse calvaria to establish a calvarial osteolysis model and investigated the biological effects of the particles on calvaria osteocytes in vivo. Results showed that TCP particles induced pyroptosis and activated the NLRP3 inflammasome in calvaria osteocytes, which was confirmed by obvious increases in empty lacunae, protein expressions of speck-like protein containing CARD (ASC), NOD-like receptor protein 3 (NLRP3), cleaved caspase-1 (Casp-1 p20) and cleaved gasdermin D (GSDMD-N), and resulted in elevated ratios of Casp-1 p20/Casp-1 and interleukin (IL)-1ß/pro-IL-1ß. Simultaneously, TCP particles enhanced serum levels of lactate dehydrogenase (LDH) and IL-1ß. Furthermore, the pyroptotic effect was reversed by the Casp-1 inhibitor VX765 or the NLRP3 inhibitor MCC950. In addition, TCP particles increased the levels of intracellular reactive oxygen species (ROS) and malonaldehyde (MDA), whereas decreased the antioxidant enzyme nuclear factor E2-related factor 2 (Nrf2) level, leading to oxidative stress in calvaria osteocytes; the ROS scavenger N-acetylcysteine (NAC) attenuated these effects of pyroptotic death and the NLPR3 activation triggered by TCP particles. Collectively, our data suggested that TCP particles promote pyroptotic death of calvaria osteocytes through the ROS/NLRP3/Caspase-1 signaling axis, contributing to osteoclastogenesis and periprosthetic osteolysis.

Brain Delivery of Curcumin Through Low-Intensity Ultrasound-Induced Blood-Brain Barrier Opening via Lipid-PLGA Nanobubbles.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder. Owing to the presence of blood-brain barrier (BBB), conventional pharmaceutical agents are difficult to the diseased nuclei and exert their action to inhibit or delay the progress of PD. Recent literatures have demonstrated that curcumin shows the great potential to treat PD. However, its applications are still difficult in vivo due to its poor druggability and low bioavailability through the BBB. METHODS: Melt-crystallization methods were used to improve the solubility of curcumin, and curcumin-loaded lipid-PLGA nanobubbles (Cur-NBs) were fabricated through encapsulating the curcumin into the cavity of lipid-PLGA nanobubbles. The bubble size, zeta potentials, ultrasound imaging capability and drug encapsulation efficiency of the Cur-NBs were characterized by a series of analytical methods. Low-intensity focused ultrasound (LIFU) combined with Cur-NB was used to open the BBB to facilitate curcumin delivery into the deep brain of PD mice, followed by behavioral evaluation for the treatment efficacy. RESULTS: The solubility of curcumin was improved by melt-crystallization methods, with 2627-fold higher than pure curcumin. The resulting Cur-NBs have a nanoscale size about 400 nm and show excellent contrast imaging performance. Curcumin drugs encapsulated into Cur-NBs could be effectively released when Cur-NBs were irradiated by LIFU at the optimized acoustic pressure, achieving 30% cumulative release rate within 6 h. Importantly, Cur-NBs combined with LIFU can open the BBB and locally deliver the curcumin into the deep-seated brain nuclei, significantly enhancing efficacy of curcumin in the Parkinson C57BL/6J mice model in comparison with only Cur-NBs and LIFU groups. CONCLUSION: In this work, we greatly improved the solubility of curcumin and developed Cur-NBs for brain delivery of curcumin against PD through combining with LIFU-mediating BBB. Cur-NBs provide a platform for these potential drugs which are difficult to cross the BBB to treat PD disease or other central nervous system (CNS) diseases.

Cellular Stress and Molecular Responses in Bladder Ischemia.

The concept of bladder ischemia as a contributing factor to detrusor overactivity and lower urinary tract symptoms (LUTS) is evolving. Bladder ischemia as a consequence of pelvic arterial atherosclerosis was first documented in experimental models and later in elderly patients with LUTS. It was shown that early-stage moderate ischemia produces detrusor overactivity, while prolonged severe ischemia provokes changes consistent with detrusor underactivity. Recent studies imply a central role of cellular energy sensors, cellular stress sensors, and stress response molecules in bladder responses to ischemia. The cellular energy sensor adenosine monophosphate-activated protein kinase was shown to play a role in detrusor overactivity and neurodegeneration in bladder ischemia. The cellular stress sensors apoptosis signal-regulating kinase 1 and caspase-3 along with heat shock proteins were characterized as important contributing factors to smooth muscle structural modifications and apoptotic responses in bladder ischemia. Downstream pathways seem to involve hypoxia-inducible factor, transforming growth factor beta, vascular endothelial growth factor, and nerve growth factor. Molecular responses to bladder ischemia were associated with differential protein expression, the accumulation of non-coded amino acids, and post-translational modifications of contractile proteins and stress response molecules. Further insight into cellular stress responses in bladder ischemia may provide novel diagnostic and therapeutic targets against LUTS.

Developing a mechanically matched decellularized spinal cord scaffold for the in situ matrix-based neural repair of spinal cord injury.

Tissue engineering is a promising strategy to repair spinal cord injury (SCI). However, a bioscaffold with mechanical properties that match those of the pathological spinal cord tissue and a pro-regenerative matrix that allows robust neurogenesis for overcoming post-SCI scar formation has yet to be developed. Here, we report that a mechanically enhanced decellularized spinal cord (DSC) scaffold with a thin poly (lactic-co-glycolic acid) (PLGA) outer shell may fulfill the requirements for effective in situ neuroengineering after SCI. Using chemical extraction and electrospinning methods, we successfully constructed PLGA thin shell-ensheathed DSC scaffolds (PLGA-DSC scaffolds) in a way that removed major inhibitory components while preserving the permissive matrix. The DSCs exhibited good cytocompatibility with neural stem cells (NSCs) and significantly enhanced their differentiation toward neurons in vitro. Due to the mechanical reinforcement, the implanted PLGA-DSC scaffolds showed markedly increased resilience to infiltration by myofibroblasts and the deposition of dense collagen matrix, thereby creating a neurogenic niche favorable for the targeted migration, residence and neuronal differentiation of endogenous NSCs after SCI. Furthermore, PLGA-DSC presented a mild immunogenic property but prominent ability to polarize macrophages from the M1 phenotype to the M2 phenotype, leading to significant tissue regeneration and functional restoration after SCI. Taken together, the results demonstrate that the mechanically matched PLGA-DSC scaffolds show promise for effective tissue repair after SCI.

Impairment of AMPK-α2 augments detrusor contractions in bladder ischemia.

PURPOSE: Ischemia disrupts cellular energy homeostasis. Adenosine monophosphate-activated protein kinase alpha-2 (AMPK-α2) is a subunit of AMPK that senses cellular energy deprivation and signals metabolic stress. Our goal was to examine the expression levels and functional role of AMPK-α2 in bladder ischemia. MATERIALS AND METHODS: Iliac artery atherosclerosis and bladder ischemia were engendered in apolipoprotein E knockout rats by partial arterial endothelial denudation using a balloon catheter. After eight weeks, total and phosphorylated AMPK-α2 expression was analyzed by western blotting. Structural integrity of AMPK-α2 protein was assessed by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). Functional role of AMPK-α2 was examined by treating animals with the AMPK activator 5-aminoimidazole-4-carboxamide-1-beta-D ribofuranoside (AICAR). Tissue contractility was measured in the organ bath and bladder nerve density was examined by immunostaining. RESULTS: Total AMPK-α2 expression increased in bladder ischemia, while phosphorylated AMPK-α2 was significantly downregulated. LC-MS/MS suggested post-translational modification of AMPK-α2 functional domains including phosphorylation sites, suggesting accumulation of catalytically inactive AMPK-α2 in bladder ischemia. Treatment of rats with AICAR diminished the force of overactive detrusor contractions and increased bladder capacity but did not have a significant effect on the frequency of bladder contractions. AICAR diminished contractile reactivity of ischemic tissues in the organ bath and prevented loss of nerve fibers in bladder ischemia. CONCLUSIONS: Ischemia induces post-translational modification of AMPK-α2 protein. Impairment of AMPK-α2 may contribute to overactive detrusor contractions and loss of nerve fibers in bladder ischemia. AMPK activators may have therapeutic potential against detrusor overactivity and neurodegeneration in bladder conditions involving ischemia.

An Injectable Multifunctional Dual-Phase Bead-Reinforced Gelatin Matrix Permissive of Mesenchymal Stem Cell Infiltration for Musculoskeletal Soft Tissue Repair.

This study develops a novel strategy for regenerative therapy of musculoskeletal soft tissue defects using a dual-phase multifunctional injectable gelatin-hydroxyphenyl propionic acid (Gtn-HPA) composite. The dual-phase gel consists of stiff, degradation-resistant, ≈2-mm diameter spherical beads made from 8 wt% Gtn-HPA in a 2 wt% Gtn-HPA matrix. The results of a 3D migration assay show that both the cell number and migration distance in the dual-phase gel system are comparable with the 2 wt% mono-phase Gtn-HPA, but notably significantly higher than for 8 wt% mono-phase Gtn-HPA (into which few cells migrated). The results also show that the dual phase gel system has degradation resistance and a prolonged growth factor release profile comparable with 8 wt% mono-phase Gtn-HPA. In addition, the compressive modulus of the 2 wt% dual-phase gel system incorporating the 8 wt% bead phase is nearly four-fold higher than the 2 wt% mono-phase gel (5.3 ± 0.4 kPa versus 1.5 ± 0.06 kPa). This novel injectable dual-phase Gtn-HPA composite thus combines the advantages of low-concentration Gtn-HPA (cell migration) with high-concentration Gtn-HPA (stiffness, degradation resistance, slower chemical release kinetics) to facilitate effective reparative/regenerative processes in musculoskeletal soft tissue.

Platelet-Derived Growth Factor Stimulated Migration of Bone Marrow Mesenchymal Stem Cells into an Injectable Gelatin-Hydroxyphenyl Propionic Acid Matrix.

Bone marrow mesenchymal stem cells (bMSCs) are responsible in the repair of injured tissue through differentiation into multiple cell types and secretion of paracrine factors, and thus have a broad application profile in tissue engineering/regenerative medicine, especially for the musculoskeletal system. The lesion due to injury or disease may be a closed irregular-shaped cavity deep within tissue necessitating an injectable biomaterial permissive of host (endogenous) cell migration, proliferation and differentiation. Gelatin-hydroxyphenyl propionic acid (Gtn-HPA) is a natural biopolymer hydrogel which is covalently cross-linked by horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) in situ and can be delivered to the lesion by needle injection. Growth factors and cytokines can be directly incorporated into the gel or into nano- and micro-particles, which can be employed for sustained release of biomolecules while maintaining their bioactivity. In this study, we selected polyelectrolyte complex nanoparticles (PCNs) prepared with dextran sulfate and chitosan as the carrier for platelet-derived growth factor (PDGF)-BB and stromal cell-derived factor (SDF)-1α, which have been tested effectively in recruiting stem cells. Our in vitro results showed a high degree of viability of bMSCs through the process of Gtn-HPA covalent cross-linking gelation. The Gtn-HPA matrix was highly permissive of bMSC migration, proliferation, and differentiation. PDGF-BB (20 ng/mL) directly incorporated into the gel and, alternatively, released from PCNs stimulated bMSC migration and proliferation. There were only small differences in the results for the direct incorporation of PDGF into the gel compared with its release from PCNs, and for increased doses of the growth factor (200 ng/mL and 2 µg/mL). In contrast, SDF-1α elicited an increase in migration and proliferation only when released from PCNs; its effect on migration was notably less than PDGF-BB. The in vitro results demonstrate that PDGF-BB substantially increases migration of bMSCs into Gtn-HPA and their proliferation in the gel, and that these benefits can be derived from incorporation of a relatively low dose of the growth factor directly into the gel. These findings commend the use of Gtn-HPA/PDGF-BB as an injectable therapeutic agent to treat defects in musculoskeletal tissues.

The effects of shock wave stimulation of mesenchymal stem cells on proliferation, migration, and differentiation in an injectable gelatin matrix for osteogenic regeneration.

The treatment of a variety of defects in bony sites could benefit from mitogenic stimulation of osteoprogenitor cells, including endogenous bone marrow-derived mesenchymal stem cells (bMSCs), and from provision of such cells with a matrix permissive of their migration, proliferation, and osteogenic differentiation. That such MSC stimulation could result from treatment with noninvasive (extracorporeal) shock waves (ESWs), and the matrix delivered by injection could enable this therapeutic approach to be employed for applications in which preformed scaffolds and growth factor therapy are difficult to deploy. The objectives of the present study were to investigate focused ESWs for their effects on proliferation, migration, and osteogenic differentiation in an injectable gelatin (Gtn) matrix capable of undergoing covalent cross-linking in vivo. Gtn was conjugated with hydroxyphenyl propionic acid (HPA) in order to enable it to be covalently cross-linked with minute amounts of horseradish peroxidase and hydrogen peroxide. The results demonstrated that 500 shocks of 0.4-mJ/mm2 energy flux density resulted in a twofold greater proliferation of bMSCs in the Gtn-HPA matrix after 14 days, compared with bMSCs grown with supplementation with platelet-derived growth factor (PDGF)-BB, a known mitogen for bMSCs. Moreover, SW treatment enhanced substantially osteogenic differentiation of bMSCs. The Gtn-HPA gel was permissive of MSC migration under the chemotactic influence of the growth factor, PDGF-BB, incorporated into and released by the gel. ESW treatment had no effect on the motility of the MSCs. The findings of the study warrant further investigation of this combined treatment modality for select bony defects.

Laparoscopic and Robotic-Assisted Partial Nephrectomy: An Overview of Hot Issues.

Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy are attracting increased attention from urologists. They can achieve the same effect of oncology control as radical nephrectomy; moreover, they can offer better preservation of renal function, thus obtaining long-term living benefits. The indications are also expanding, making it possible for larger and more difficult tumors. Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy can be performed by transperitoneal and retroperitoneal approaches, with their individual advantages and limitations. In addition, the renal tumor scoring systems have been widely used and studied in laparoscopic partial nephrectomy and robot-assisted partial nephrectomy. In -order to better preserve renal function, the zero-ischemia technique is widely used. The application of intraoperative imaging technology provides convenience and greater benefits. Besides, whether minimal invasive partial nephrectomy can be performed without stop antiplatelet treatment is still disputed. Clinicians perform substantial exploration and practice to achieve the "trifecta" of surgery: complete resection of the tumor, maximum protection of renal function, and no complications.

Vascular Endothelial Growth Factor 165-Binding Heparan Sulfate Promotes Functional Recovery From Cerebral Ischemia.

BACKGROUND AND PURPOSE: Although VEGF165 (vascular endothelial growth factor-165) is able to enhance both angiogenesis and neurogenesis, it also increases vascular permeability through the blood-brain barrier. Heparan sulfate (HS) sugars play important roles in regulating VEGF bioactivity in the pericellular compartment. Here we asked whether an affinity-purified VEGF165-binding HS (HS7) could augment endogenous VEGF activity during stroke recovery without affecting blood-brain barrier function. METHODS: Both rat brain endothelial cell line 4 and primary rat neural progenitor cells were used to evaluate the potential angiogenic and neurogenic effects of HS7 in vitro. For in vivo experiments, male Sprague-Dawley rats were subjected to 100 minutes of transient focal cerebral ischemia, then treated after 4 days with either PBS or HS7. One week later, infarct volume, behavioral sequelae, immunohistochemical markers of angiogenesis and neural stem cell proliferation were assessed. RESULTS: HS7 significantly enhanced VEGF165-mediated angiogenesis in rat brain endothelial cell line 4 brain endothelial cells, and increased the proliferation and differentiation of primary neural progenitor cells, both via the VEGFR2 (vascular endothelial growth factor receptor 2) pathway. Intracerebroventricular injection of HS7 improved neurological outcome in ischemic rats without changing infarct volumes. Immunostaining of the compromised cerebrum demonstrated increases in collagen IV/Ki67 and nestin/Ki67 after HS7 exposure, consistent with its ability to promote angiogenesis and neurogenesis, without compromising blood-brain barrier integrity. CONCLUSIONS: A VEGF-activating glycosaminoglycan sugar, by itself, is able to enhance endogenous VEGF165 activity during the post-ischemic recovery phase of stroke.

Mangiferin Relieves Lipopolysaccharide-Induced Injury by Up-Regulating miR-181a via Targeting PTEN in ATDC5 Cells.

BACKGROUND: Mangiferin (MF) was reported to possess anti-inflammatory activity. This investigation tried to probe into the underlying mechanism of MF in osteoarthritis. METHODS: ATDC5 cells were pretreated with series concentrations of MF (0.1, 1, 5, 10, 15, 20 µM) for 2 h and then were exposed to lipopolysaccharide (LPS) (5 µg/ml) for 12 h to construct the inflammatory injury model. The cell viability, productions of pro-inflammatory cytokines and enzymes were respectively measured by employing CCK-8 assay, western blot, ELISA, and quantitative reverse-transcription (qRT)-PCR. miR-181a expression was altered by employing cell transfection. Dichloro-dihydro-fluorescein diacetate (DCFH-DA) method was employed for detection of reactive oxygen species (ROS) generation. Dual luciferase activity assay was conducted for analyzing the relationship between miR-181a and PTEN. The underlying mechanism was determined by employing western blot. RESULTS: High doses of MF treatment (15 and 20 µM) noticeably induced inflammatory injury exhibiting as increased the productions of pro-inflammatory cytokines, enzymes and ROS, activated NF-κB pathway and deactivated PTEN/PI3K/AKT pathway in ATDC5 cells. Besides, MF treatment notably remitted LPS-induced inflammatory injury through deactivation of NF-κB pathway and activation of PTEN/PI3K/AKT pathway. PTEN was a target of miR-181a. Inhibition of miR-181a remarkably reversed MF-triggered impacts on ATDC5 cells. CONCLUSION: MF attenuated LPS-induced inflammatory damage through miR-181a/PTEN axis and thereby inhibiting NF-κB pathway and activating PI3K/AKT pathway.

Extracorporeal Shock Wave Stimulates Angiogenesis and Collagen Production in Facial Soft Tissue.

BACKGROUND: This study investigated the efficacy of extracorporeal shock wave (ESW) application in stimulating dermal thickness, vascularity, and collagen synthesis of facial skin in a large animal model. MATERIALS AND METHODS: The facial skin of the maxillary and mandibular areas of goats (n = 6 per group) was treated with ESWs of different intensities (0.15 and 0.45 mJ/mm2; 1000 pulses). After 4 d, histology and immunohistochemistry were used to evaluate the following: dermal thickness, total number and abundance of microvessels, amount of type 1 collagen, and α-smooth muscle actin expression. RESULTS: Dermal thickness, number and abundance of microvessels, and collagen synthesis increased after ESW application at both intensities (each P < 0.05). When comparing ESW groups, the highest collagen abundance was seen after 0.15 mJ/mm2 (P = 0.034), whereas the highest number of microvessels was detected after treatment with 0.45 mJ/mm2 (P = 0.002). CONCLUSIONS: A single-session application of focused low-energy ESWs to facial skin can increase dermal thickness by stimulating collagen production and local microcirculation. These findings commend the technique for future investigation for pretreatment of local or microvascular skin flaps to enhance tissue healing.

Paeonol attenuates isoflurane anesthesia-induced hippocampal neurotoxicity via modulation of JNK/ERK/P38MAPK pathway and regulates histone acetylation in neonatal rat.

Objective: Volatile anesthetic such as isoflurane causes widespread neurodegeneration in the developing animal brains and also induces cognitive impairments. Paeonol is a plant-derived phenolic compound possessing numerous bioactive properties. The study investigates the neuroprotective effects of paeonol against isoflurane-induced neurodegeneration and cognitive disturbances in neonatal rats.Methods: Paeonol (50, 100, and 150 mg/kg body weight/day) was given orally to separate groups of neonatal rats from postnatal day 3 (P3) to P21 and were exposed to isoflurane (0.75%; 6 h) on P7.Results: Neuroapoptosis following isoflurane exposure was remarkably reduced by paeonol. Isoflurane-induced elevated cleaved caspase-3, Bad, and Bax expression, were down-regulated on paeonol administration. Paeonol significantly enhanced expression of antiapoptotic proteins (Bcl-2, Bcl-xL, xIAP, c-IAP-1, c-IAP-2, and survivin) and improved acetylation of HK39 and HK412. The expression of histone deacetylases (HDACs)-HDAC2 and HDAC-3 were down-regulated. Isoflurane-induced activation of JNK/p38MAPK signaling and suppressed ERK signaling and were effectively regulated by paeonol. General behavior and freezing responses of the rats were improved. Results of the Morris Water Maze tests revealed improved learning and memory retention on paeonol treatment.Conclusions: Paeonol effectively inhibited neuroapoptosis and improved isoflurane-induced cognitive dysfunctions via regulating histone acetylation and JNK/ERK1/2/p38MAPK signaling pathways.

Translational relevance of the goat as a preclinical model of the human labrum and chondrolabral junction-histological study.

The purpose of this study was to evaluate the histologic features of the caprine labrum, with emphasis on the chondrolabral junction, with the goal of informing the feasibility of the goat as an animal model. The left hip joint of six adolescent Spanish goats (Capra pyrenaica) was harvested and subjected to anatomical and histological assessments. Human acetabular and femoral head samples, collected during total hip arthroplasty, served as comparison samples. The caprine labrum was found to consist of mostly type I collagen with uniform crimp, with an average crimp length of 20.8 µm. Upon histological assessment, acetabular articular chondrocytes were found to express substance-P, especially near or in the chondrolabral junction. And the majority of nonvascular cells expressed α-smooth muscle actin (SMA), with no notable elastin and laminin expression. Human labrum demonstrated similar staining patterns. Overall, the goat hip was found to be homologous to the human hip, demonstrating potential as a useful animal model for future studies. This is the first report of a crimped collagen structure in the labrum. Crimped type I collagen at the chondrolabral junction imparts an extension-recovery property which allows for toleration of stress without permanent deformation, underlying the importance of its preservation during surgery. The high expression of substance-P reflects the degree to which the labrum is innervated. Finally, the expression of α-SMA with contractile characteristics could indicate the potential for chondrocyte (i.e., myochondrocytes) modeling of the extracellular matrix. Statement of Clinical Significance: Establishment of a large animal model and deeper knowledge of the histological composition of the hip joint will enhance our study of the acetabular labrum, including repair techniques. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1070-1080, 2020.

Promoting Neuro-Supportive Properties of Astrocytes with Epidermal Growth Factor Hydrogels.

Biomaterials provide novel platforms to deliver stem cell and growth factor therapies for central nervous system (CNS) repair. The majority of these approaches have focused on the promotion of neural progenitor cells and neurogenesis. However, it is now increasingly recognized that glial responses are critical for recovery in the entire neurovascular unit. In this study, we investigated the cellular effects of epidermal growth factor (EGF) containing hydrogels on primary astrocyte cultures. Both EGF alone and EGF-hydrogel equally promoted astrocyte proliferation, but EGF-hydrogels further enhanced astrocyte activation, as evidenced by a significantly elevated Glial fibrillary acidic protein (GFAP) gene expression. Thereafter, conditioned media from astrocytes activated by EGF-hydrogel protected neurons against injury and promoted synaptic plasticity after oxygen-glucose deprivation. Taken together, these findings suggest that EGF-hydrogels can shift astrocytes into neuro-supportive phenotypes. Consistent with this idea, quantitative-polymerase chain reaction (qPCR) demonstrated that EGF-hydrogels shifted astrocytes in part by downregulating potentially negative A1-like genes (Fbln5 and Rt1-S3) and upregulating potentially beneficial A2-like genes (Clcf1, Tgm1, and Ptgs2). Further studies are warranted to explore the idea of using biomaterials to modify astrocyte behavior and thus indirectly augment neuroprotection and neuroplasticity in the context of stem cell and growth factor therapies for the CNS. Stem Cells Translational Medicine 2019;8:1242&1248.