Preservation Efficacy of a Quercetin and Sucrose Solution for Warm Ischemically Damaged Porcine Liver Grafts.

BACKGROUND: The University of Wisconsin (UW) solution is the gold standard for preserving the liver, kidneys, and pancreas. For renal preservation, the addition of the flavonoid, quercetin (QE), to the preservation solution reduces damage to renal tubular cells, and the addition of sucrose (Suc) is also beneficial for preservation. The aim of this study was to investigate the protective effects of QE and Suc on porcine livers in terms of warm and cold injury and to evaluate whether their use improves ischemia-reperfusion (I/R) injury after simple cold storage (CS). METHODS: We tested porcine livers procured after 30 minutes of warm ischemia followed by preservation for 6 hours under the following 2 conditions: group 1, preserved with the CS/UW solution (n = 4); group 2, preserved with the CS/UW solution containing Que 33.1 µM and Suc 0.1 M (n = 6). All livers were evaluated using an ex vivo isolated liver reperfusion model with saline-diluted autologous blood. RESULTS: Aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels in group 2 were significantly lower at 30 minutes of reperfusion than in group 1. Furthermore, histologic evaluation by hematoxylin and eosin staining showed significantly fewer morphologic changes in group 2 than in group 1, as indicated by the total Suzuki score. Group 2 also had significantly better scores for sinusoidal congestion and hepatocyte cytoplasmic vacuolization. CONCLUSION: Adding Que and Suc to the UW solution can effectively prevent cold injury in livers donated after circulatory death.

[A case of intraductal tubulopapillary adenocarcinoma with bone metastases].

A woman in her 70s with main pancreatic duct dilatation was referred to our hospital. Various imaging examinations showed an extensive mass within the lumen of the main pancreatic duct in the head and body of the pancreas. The microscopic examination of a biopsy specimen revealed an adenocarcinoma. She was diagnosed with intraductal tubulopapillary adenocarcinoma of the pancreas;a pylorus-preserving total pancreatectomy was subsequently performed. However, 30 days after surgery, the patient presented with neck pain and left upper arm numbness. Results of magnetic resonance imaging and bone scintigraphy revealed a cervical spinal tumor that was subsequently biopsied. The patient was diagnosed with intraductal tubulopapillary adenocarcinoma with bone metastasis.

Optimizing the layer thickness of sol-gel-derived TiO2 coating on polyetheretherketone.

Sol-gel-derived TiO2 coatings have been confirmed to effectively promote bone-bonding behavior on polyetheretherketone (PEEK) surfaces; however, the optimal layer thickness to maximize the osseointegration and adhesive performance has not been yet determined. In this study, we applied sol-gel-derived TiO2 coatings with different layer thicknesses (40 and 120 nm) on PEEK implants to determine the effects of layer thickness on the surface characteristics, adhesive strength, and bone bonding capabilities (including histological osseointegration). The surface analysis results of both coated implants indicated no significant differences concerning the water contact angle, layer adhesion strength, and apatite formation ability in a simulated body fluid. Additionally, the in vivo biomechanical tests revealed a higher bone-bonding strength for both coated PEEK implants (compared with that of the uncoated sample). It was thus concluded that the factor of layer thickness marginally influences the bioactive advantages attained by sol-gel-derived TiO2 coatings on PEEK surfaces, highlighting the significant versatility and clinical availability of this coating technology.

Titania-Containing Bone Cement Shows Excellent Osteoconductivity in a Synovial Fluid Environment and Bone-Bonding Strength in Osteoporosis.

Titania bone cement (TBC) reportedly has excellent in vivo bioactivity, yet its osteoconductivity in synovial fluid environments and bone-bonding ability in osteoporosis have not previously been investigated. We aimed to compare the osteoconductivity of two types of cement in a synovial fluid environment and determine their bone-bonding ability in osteoporosis. We implanted TBC and commercial polymethylmethacrylate bone cement (PBC) into rabbit femoral condyles and exposed them to synovial fluid pressure. Rabbits were then euthanized at 6, 12, and 26 weeks, and affinity indices were measured to evaluate osteoconductivity. We generated a rabbit model of osteoporosis through bilateral ovariectomy (OVX) and an 8-week treatment with methylprednisolone sodium succinate (PSL). Pre-hardened TBC and PBC were implanted into the femoral diaphysis of the rabbits in the sham control and OVX + PSL groups. Affinity indices were significantly higher for TBC than for PBC at 12 weeks (40.9 ± 16.8% versus 24.5 ± 9.02%) and 26 weeks (40.2 ± 12.7% versus 21.2 ± 14.2%). The interfacial shear strength was significantly higher for TBC than for PBC at 6 weeks (3.69 ± 1.89 N/mm2 versus 1.71 ± 1.23 N/mm2) in the OVX + PSL group. These results indicate that TBC is a promising bioactive bone cement for prosthesis fixation in total knee arthroplasty, especially for osteoporosis patients.

Bioactivity and antibacterial activity of strontium and silver ion releasing titanium.

To overcome problems associated with loosening of orthopedic implants and surgical site infections, we developed a novel, titanium (Ti)-based material that releases both strontium and silver ions (CaSrAg-Ti) based on alkali-and-heat treatment. The results of commercially pure Ti (cp-Ti), Ti that releases Sr ions only (CaSr-Ti), and the novel CaSrAg-Ti material were compared. Mechanical tests were performed to evaluate the in vivo bonding properties of CaSrAg-Ti and the bone-implant contact (BIC) ratio in histological specimens was determined at 4 and 8 weeks after implantation in a rat femur. Also, the in vitro antibacterial activities of this material against methicillin-susceptible Staphylococcus aureus (MSSA) were evaluated after a 24 h incubation period by assaying colony-forming units. In addition, antibacterial activities were evaluated in vivo at 7 days after implantation in a rat subcutaneous pocket model. There was direct contact between the bone and CaSrAg-Ti in histological specimens and no apparent signs of argyrosis in any rat. The bone-bonding strength and the BIC ratio were increased by 2.7- and 2.3-fold for CaSrAg-Ti vs. cp-Ti at 4 weeks and 2.2- and 2.0-fold at 8 weeks, respectively. As compared with cp-Ti, the number of viable MSSA remaining on CaSrAg-Ti was reduced by 100 ± 0% in vitro and 94.2 ± 6.9% in vivo. Ti that releases Sr and Ag ions is a promising material that exhibits both bone-bonding properties and anti-MSSA activities.

In vivo and in vitro bioactivity of a "precursor of apatite" treatment on polyetheretherketone.

We recently developed a surface treatment, "precursor of apatite" (PrA), for polyetheretherketone (PrA-PEEK) via a simple, low-temperature process aiming to achieve stronger and faster adhesion to bone. The treatment involves three steps: H2SO4 immersion, exposure to O2 plasma discharge, and alkaline simulated body fluid (alkaline SBF) treatment. This method produces homogeneous fine particles of amorphous calcium phosphate on the PEEK, and we confirmed that PrA-PEEK had excellent apatite formation ability in an SBF immersion test. In the present study using PEEK implants in rabbit tibia, mechanical tests, and histological and radiological analyses revealed that PrA provided the PEEK substrate with excellent bone-bonding properties and osteo-conductivity at early stages (4 and 8 weeks), extending to 16 weeks. In vitro study using MC3T3-E1 cells revealed via XTT assay that PrA on the PEEK substrate resulted in no cytotoxicity, though PrA treatment seemed to suppress gene expression of integrin ß-1 and Alp after 7-day incubation as shown by real-time PCR. On the whole, PrA treatment succeeded in giving in vivo bone-bonding properties to the PEEK substrate, and the treatment is a safe and promising method that can be applied in clinical settings. There was an inconsistency between in vivo and in vitro bioactivity, and this discrepancy indicated that apatite formation does not always need activation of osteoblasts at very early stage and that optimal conditions at cell and organism level may be different. STATEMENT OF SIGNIFICANCE: Polyetheretherketone (PEEK) is an attractive engineering polymer used for spine and dental surgery. To further improve clinical outcome of PEEK-based materials, we developed "Precursor of apatite" (PrA) treatment on the PEEK surface to confer bone-bonding properties. The advantages of this treatment are that it does not require high-temperature processing or special chemicals, and it is inexpensive. The present study clarified excellent in vivo bone-bonding property of PrA treatment. In addition, the results revealed important insights indicating that optimal conditions, especially wettability and crystallinity in calcium phosphate, differ at cell and organism levels. Moreover, our results indicated that prediction of in vivo bioactivity should be done in combination with multiple in vitro tests.

Titania-containing bioactive bone cement for total hip arthroplasty in dogs.

We developed a composite cement containing low-content bioactive titania fillers dispersed among specific polymethylmethacrylate (PMMA) polymers and investigated the mechanical properties and bioactivity of this titania bone cement (TBC) under load-bearing conditions in cemented total hip arthroplasty (THA) in adult female beagles. TBC and PMMA bone cement (PBC) were compared using custom-made prostheses. The dogs were killed 1, 3, 6, and 12 months postoperatively. The acetabulum was harvested to evaluate the osteoconductivity of the cement, whereas the femur was harvested for the push-out test and histological analyses. The compressive strength of TBC was significantly higher than that of PBC (p < 0.001), whereas the flexural and tensile strengths, as well as fracture toughness, were equivalent. The bonding strength values for TBC and PBC were 72.9 and 58.0 N/mm at 1 month, 69.4 and 57.2 N/mm at 3 months, 106.1 and 85.0 N/mm at 6 months, and 114.3 and 100.7 N/mm at 12 months, respectively. Histologically, TBC was in direct contact with bone without intervening with fibrous tissue over larger areas and newly formed bone was observed along the cement. The excellent mechanical properties and apparent bioactivity of this novel bone cement indicate its potential utility in clinical practice. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1238-1245, 2019.

A novel small compound SH-2251 suppresses Th2 cell-dependent airway inflammation through selective modulation of chromatin status at the Il5 gene locus.

IL-5 is a key cytokine that plays an important role in the development of pathological conditions in allergic inflammation. Identifying strategies to inhibit IL-5 production is important in order to establish new therapies for treating allergic inflammation. We found that SH-2251, a novel thioamide-related small compound, selectively inhibits the differentiation of IL-5-producing Th2 cells. SH-2251 inhibited the induction of active histone marks at the Il5 gene locus during Th2 cell differentiation. The recruitment of RNA polymerase II, and following expression of the Th2 cell-specific intergenic transcripts around the Il5 gene locus was also inhibited. Furthermore, Th2 cell-dependent airway inflammation in mice was suppressed by the oral administration of SH-2251. Gfi1, a transcriptional repressor, was identified as a downstream target molecule of SH-2251 using a DNA microarray analysis. The Gfi1 expression dramatically decreased in SH-2251-treated Th2 cells, and the SH-2251-mediated inhibition of IL-5-producing Th2 cell differentiation was restored by transduction of Gfi1. Therefore, our study unearthed SH-2251 as a novel therapeutic candidate for allergic inflammation that selectively inhibits active histone marks at the Il5 gene locus.

Spatiotemporal regulation of the kinase Mst1 by binding protein RAPL is critical for lymphocyte polarity and adhesion.

RAPL, a protein that binds the small GTPase Rap1, is required for efficient immune cell trafficking. Here we have identified the kinase Mst1 as a critical effector of RAPL. RAPL regulated the localization and kinase activity of Mst1. 'Knockdown' of the gene encoding Mst1 demonstrated its requirement for the induction of both a polarized morphology and integrin LFA-1 clustering and adhesion triggered by chemokines and T cell receptor ligation. RAPL and Mst1 localized to vesicular compartments and dynamically translocated with LFA-1 to the leading edge upon Rap1 activation, suggesting a regulatory function for the RAPL-Mst1 complex in intracellular transport of LFA-1. Our study demonstrates a previously unknown function for Mst1 of relaying the Rap1-RAPL signal to induce cell polarity and adhesion of lymphocytes.

Inhibitory effects of the new anti-inflammatory agent, IS-741, on spontaneous colitis in HLA-B27/beta2-microglobulin transgenic rats.

BACKGROUND: A novel anti-inflammatory drug, IS-741, blocked the adhesion of inflammatory cells to microvascular endothelial cells both in vivo and in vitro. Transgenic rats expressing human leukocyte antigen (HLA)-B27 and human beta2-microglobulin (HLA-B27 rats) spontaneously develop chronic colitis, which resembles human inflammatory bowel disease. In the present study, the authors examined the efficacy of IS-741 against spontaneous colitis in HLA-B27 rats. METHODS: The HLA-B 27 rats were divided in two groups after the development of colitis. IS-741 was dissolved in water and administered orally (10 mg/kg) once per day for 14 days. RESULTS: The HLA-B27 rats treated with IS-741 remained healthy; the wet weight of the colon was significantly lower in the IS-741-treated group. Histological examinations revealed a marked infiltration of inflammatory cells into both the mucosa and the submucosa in the control HLA-B27 rats, but these changes were attenuated in the IS-741-treated group. The mucosal damage score was also significantly reduced by treatment with IS-741. IS-741 significantly reduced the mucosal myeloperoxidase activity and mucosal cytokine-induced neutrophil chemoattractant-1 levels. IS-741 also reduced CD3-positive T-cell infiltration. CONCLUSION: IS-741 suppressed the spontaneous colitis that developed in HLA-B27 rats. Some of the actions of IS-741 may be associated with its inhibitory effects on the adhesion of neutrophils to endothelial cells. The findings from the present study suggest that IS-741 may be a useful new therapeutic agent for inflammatory bowel disease.