Factors Affecting an Increase in Spleen Volume and Association of Spleen Volume Variation with the Clinical Outcomes of Atezolizumab and Bevacizumab Treatment for Hepatocellular Carcinoma: A Retrospective Analysis.

INTRODUCTION: Gastrointestinal varices rupture is considered to be prone to occur during atezolizumab and bevacizumab (Atez/Bev) treatment. This study aimed to investigate predictive factors affecting the increase in spleen volume (SpV) and the association of SpV variation with the clinical outcomes of Atez/Bev. METHODS: A total of 164 HCC patients were included in this retrospective multicenter study. We measured SpV based on CT scans obtained before treatment and at evaluations. We used the inverse probability of treatment weight to address the imbalance between patient characteristics. RESULTS: The median pretreatment SpV was 184 (130-257) cm3 and the median SpV variation was 27 (9-60) cm3. An increase in the SpV was observed in 140 patients (85.4%). Age <74 years (p = 0.03), mALBI grade 2b or 3 (p = 0.03), and pretreatment SpV ≥184 cm3 (p < 0.001) were significantly associated with increased SpV. There were no significant differences in progression-free survival (PFS) or overall survival (OS) between patients with SpV variation <25 cm3 and those with SpV variation ≥25 cm3 in the crude (p = 0.3 and 0.7) and IPTW-weighted cohorts (p = 0.08 and 0.8, respectively). Regarding pretreatment SpV, there were no significant differences in PFS or OS between patients with and without pretreatment spleen enlargement in the crude (both p = 0.3) and IPTW-weighted cohort (p = 0.6 and 0.3, respectively). CONCLUSION: Caution is warranted to detect the aggravation of portal hypertension when administering Atez/Bev to young patients or patients with an impaired liver function or pretreatment spleen enlargement. The impact of spleen modulation by Atez/Bev appears to be limited on clinical efficacy.

Comparison of 2-octyl cyanoacrylate with polyester mesh with standard suture and staples in total knee and hip arthroplasty.

OBJECTIVE: The use of 2-octyl cyanoacrylate with polyester mesh (OCA-M) has become common in total hip and knee arthroplasty (THA, TKA). We aimed to compare the safety and cosmetic outcomes between OCA-M and standard suture techniques and staples, and determine whether OCA-M can safely be used for TKA. METHOD: Inclusion criteria were patients who underwent THA or TKA from January 2010 to October 2011 (Suture group), November 2011 to August 2013 (Staple group), March 2017 to September 2018 (OCA-M group). Exclusion criteria was loss of imaging data. Complications during hospitalisation (early complication) and after discharge (late complication) were compared in groups. Plastic and orthopaedic surgeons performed cosmetic evaluations with the modified Vancouver Scar Scale (VSS) and Likert scale at three and six months postoperatively and compared in groups. RESULTS: A total of 249 arthroplasties (suture group=88 patients; staple group=94 patients; OCA-M group=67 patients) were included in the study. The OCA-M group had a significantly lower early complication rate than the suture group (p=0.015). For THA, the OCA-M group had a significantly lower total complication rate than the suture group (p=0.048). For TKA, there was no significant difference among the three groups. The complication rate in the OCA-M group showed no significant difference between THA/TKA. With regards to the VSS, the OCA-M group was significantly better for cosmetic qualities than the suture group (p=<0.001, p=0.021 at three and six months, respectively). For the Likert scale, the OCA-M group was also significantly better for cosmetic qualities than the suture group and staple group (suture-OCA-M, p=0.003 (three months), p=<0.001 (six months); staple-OCA-M, p=0.027 (three months)). CONCLUSION: In this study, the OCA-M complication rate was low compared to suturing and similar to stapling. Moreover, better cosmetic outcomes were achieved compared to suturing and stapling.

Increased Spleen Volume in Hepatocellular Carcinoma Patients Treated with Atezolizumab plus Bevacizumab in Comparison to Lenvatinib: A Retrospective Analysis.

INTRODUCTION: We previously reported 2 cases of esophageal varices rupture during atezolizumab and bevacizumab (Atez/Bev) treatment, in which the spleen volume gradually increased. The aim of this retrospective study is to compare the chronological change in spleen volume of patients treated with Atez/Bev and lenvatinib (LEN). METHODS: Seventy-two patients (Atez/Bev group, n = 26; LEN group, n = 46) were included in this retrospective study. The splenic parenchyma area was measured based on CT imaging. We used mixed-effect regression models with random intercepts to test the difference in the rate of change in spleen volume between the Atez/Bev and LEN groups. RESULTS: The median age of the Atez/Bev and LEN groups was 74.0 (71.0-82.0) and 72.0 (67.5-76.0), respectively. About 80% patients were male. The mALBI grade was classified as 1, 2a, 2b, and 3 in 10 (38.5%), 6 (23.1%), 10 (38.5%), and zero (0.0%) patients, respectively, in the Atez/Bev group and 21 (45.7%), 9 (19.6%), 15 (32.6%), and 1 (2.2%) patient in the LEN group (p = 0.9). The median baseline neutrophil-to-lymphocyte ratio (NLR) was 2.61 (1.80-3.41) in the Atez/Bev group and 2.71 (1.76-3.67) in the LEN group (p = 1.0). The median baseline spleen volume was 185 (132-246) cm3 in the Atez/Bev group and 231 (150-355) cm3 in the LEN group. The spleen volume gradually increased during Atez/Bev treatment (2.41 cm3 per week), while it was mostly consistent during LEN treatment (0.32 cm3 per week). Among patients with mALBI grade 2b or 3, the spleen volume increased in the Atez/Bev group (2.99 cm3 per week) and slightly decreased in the LEN group (0.82 cm3 per week), without statistical significance (p = 0.07). Among patients with a baseline NLR of >2.68, the spleen volume increased at a rate of 2.57 cm3 per week in the Atez/Bev group and decreased at a rate of 1.18 cm3 per week in the LEN group. The difference in the slope of the two groups was statistically significant (p = 0.04). DISCUSSION/CONCLUSION: Atez/Bev treatment could result in an increased spleen volume. Caution is required when managing patients treated with Atez/Bev, especially those with a high NLR.

Potential risk of medial cortex perforation due to peg position of morphometric tibial component in unicompartmental knee arthroplasty: a computer simulation study.

PURPOSE: The purpose of this study is to evaluate the risk of medial tibial cortical perforation in unicompartmental knee arthroplasty (UKA) due to peg positions on the tibial tray of the Persona Partial Knee (PPK). METHODS: Preoperative CT images of 60 patients and 60 osteoarthritic knees (30 male and 30 female patients) were used. A tibial multiplanar reconstruction (MPR) image was reconstructed in preoperative planning software, and the implant was placed in a virtual osteotomy plane. In addition to PPK, Zimmer Unicompartmental Knee (ZUK) and TRIBRID (TBD) were used for evaluation. The horizontal distances from the medial tibial cortex to the anterior and posterior pegs (APCD/PPCD, respectively) were measured under neutral, 3-degree varus, 3-degree valgus and 2 mm distal positions. The differences between implants under the same positions and between positions using the same implants were compared. The percentage of total cases with APCD/PPCD of less than 3 mm and the perforation risk rate were calculated. RESULTS: The APCD of PPK was significantly shorter at all positions except for the varus position of TBD. The PPCD of PPK was significantly shorter at all positions compared to ZUK and TBD. There were no cases with an APCD of less than 3 mm. Except for varus positions, the perforation risk rate of PPCD was significantly higher for PPK than the other two implants. CONCLUSION: The posterior pegs of the PPK are located more medially than the other two implants, which may result in perforation of the medial tibial cortex during implantation. Surgeons should consider the risk involved in the type of implant used.

A new remnant preservation technique reduces bone tunnel enlargement after anatomic double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To investigate the effect of a new remnant preservation technique with a focus on remnant continuity on postoperative femoral and tibial tunnel enlargement after anatomical double-bundle anterior cruciate ligament reconstruction (ACLR). METHODS: A total of 150 knees were divided into three groups: Preservation Group (Group P: 49 knees), wherein the remnant continuity remained after tunnel creation; Resection Group (Group R: 47 knees), wherein the remaining remnant was resected, and Absent Group (Group A: 54 knees), wherein the remnant had no femoral attachment before tunnel creation. In Group P, the remnant maintained continuity, and the anteromedial (AM) and posterolateral (PL) bundles were positioned anterior and posterior to the remnant, respectively. Computed tomographic scans were performed at 1 week and 1 year after surgery, and the cross-sectional area of each tunnel aperture was measured. Tunnel enlargement was compared among the three groups by one-way analysis of variance (ANOVA) and the Bonferroni test. Univariate and multivariate logistic analyses were performed to identify the risk factors for tunnel enlargement in demographic and radiographic data. RESULT: For femoral AM tunnels, the tunnel enlargement of Group P was significantly smaller than Groups R and A (p < 0.001), femoral PL (p < 0.001 vs. R and A), tibial AM (p < 0.001 vs. R, 0.002 vs. A), and tibial PL (p < 0.001 vs. R, 0.002 vs. A). There was no significant difference between Groups R and A. Multivariate logistic analysis showed that remnant preservation was a significant factor in reducing tunnel enlargement in the femoral AM, femoral PL, tibial AM, and tibial PL. CONCLUSION: The new remnant-preserving anatomical double-bundle ACLR, which preserves the continuity of the remnant, prevented all bone tunnel enlargement at 1 year postoperatively. LEVEL OF EVIDENCE: Level III.

Structurally different lysophosphatidylethanolamine species stimulate neurite outgrowth in cultured cortical neurons via distinct G-protein-coupled receptors and signaling cascades.

Neurite outgrowth is important in neuronal circuit formation and functions, and for regeneration of neuronal networks following trauma and disease in the brain. Thus, identification and characterization of the molecules that regulate neurite outgrowth are essential for understanding how brain circuits form and function and for the development of treatment of neurological disorders. In this study, we found that structurally different lysophosphatidylethanolamine (LPE) species, palmitoyl-LPE (16:0 LPE) and stearoyl-LPE (18:0 LPE), stimulate neurite growth in cultured cortical neurons. Interestingly, YM-254890, an inhibitor of Gq/11 protein, inhibited 16:0 LPE-stimulated neurite outgrowth but not 18:0 LPE-stimulated neurite outgrowth. In contrast, pertussis toxin, an inhibitor of Gi/Go proteins, inhibited 18:0 LPE-stimulated neurite outgrowth but not 16:0 LPE-stimulated neurite outgrowth. The effects of protein kinase C inhibitors on neurite outgrowth were also different. In addition, both 16:0 LPE and 18:0 LPE activate mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2, but the effect of the MAPK inhibitor differed between the 16:0 LPE- and 18:0 LPE-treated cultures. Collectively, the results suggest that the structurally different LPE species, 16:0 LPE and 18:0 LPE stimulate neurite outgrowth through distinct signaling cascades in cultured cortical neurons and that distinct G protein-coupled receptors are involved in these processes.

Evaluation of MC3T3-E1 Cell Osteogenesis in Different Cell Culture Media.

Many biomaterials have been evaluated using cultured cells. In particular, osteoblast-like cells are often used to evaluate the osteocompatibility, hard-tissue-regeneration, osteoconductive, and osteoinductive characteristics of biomaterials. However, the evaluation of biomaterial osteogenesis-inducing capacity using osteoblast-like cells is not standardized; instead, it is performed under laboratory-specific culture conditions with different culture media. However, the effect of different media conditions on bone formation has not been investigated. Here, we aimed to evaluate the osteogenesis of MC3T3-E1 cells, one of the most commonly used osteoblast-like cell lines for osteogenesis evaluation, and assayed cell proliferation, alkaline phosphatase activity, expression of osteoblast markers, and calcification under varying culture media conditions. Furthermore, the various media conditions were tested in uncoated plates and plates coated with collagen type I and poly-L-lysine, highly biocompatible molecules commonly used as pseudobiomaterials. We found that the type of base medium, the presence or absence of vitamin C, and the freshness of the medium may affect biomaterial regeneration. We posit that an in vitro model that recapitulates in vivo bone formation should be established before evaluating biomaterials.

Anti-PD-1 antibody decreases tumour-infiltrating regulatory T cells.

BACKGROUND: There are many types of therapies for cancer. In these days, immunotherapies, especially immune checkpoint inhibitors, are focused on. Though many types of immune checkpoint inhibitors are there, the difference of effect and its mechanism are unclear. Some reports suggest the response rate of anti-PD-1 antibody is superior to that of anti-PD-L1 antibody and could potentially produce different mechanisms of action. On the other hand, Treg also express PD-1; however, their relationship remains unclear. METHODS: In this study, we used osteosarcoma cell lines in vitro and osteosarcoma mouse model in vivo. In vitro, we analyzed the effect of IFNγ for expression of PD-L1 on the surface of cell lines by flowcytometry. In vivo, murine osteosarcoma cell line LM8 was subcutaneously transplanted into the dorsum of mice. Mouse anti-PD-1 antibody was intraperitoneally administered. we analysed the effect for survival of anti-PD-1 antibody and proportion of T cells in the tumour by flowcytometry. RESULTS: We discovered that IFNγ increased PD-L1 expression on the surface of osteosarcoma cell lines. In assessing the relationship between anti-PD-1 antibody and Treg, we discovered the administration of anti-PD-1 antibody suppresses increases in tumour volume and prolongs overall survival time. In the tumour microenvironment, we found that the administration of anti-PD-1 antibody decreased Treg within the tumour and increased tumour-infiltrating lymphocytes. CONCLUSIONS: Here we clarify for the first time an additional mechanism of anti-tumour effect-as exerted by anti-PD-1 antibody decreasing Treg- we anticipate that our findings will lead to the development of new methods for cancer treatment.

A Review of T-Cell Related Therapy for Osteosarcoma.

Osteosarcoma is one of the most common primary malignant tumors of bone. The combination of chemotherapy and surgery makes the prognosis better than before, but therapy has not dramatically improved over the last three decades. This is partially because of the lack of a novel specialized drug for osteosarcoma, which is known as a tumor with heterogeneity. On the other hand, immunotherapy has been one of the most widely used strategies for many cancers over the last ten years. The therapies related to T-cell response, such as immune checkpoint inhibitor and chimeric antigen receptor T-cell therapy, are well-known options for some cancers. In this review, we offer the accumulated knowledge of T-cell-related immunotherapy for osteosarcoma, and discuss the future of the therapy.

Remnant-Preserving Tibial Tunnel Positioning Using Anatomic Landmarks in Double-Bundle Anterior Cruciate Ligament Reconstruction.

PURPOSE: To assess (1) if 6 anatomic landmarks (ALs) could be arthroscopically confirmed with remnant preservation and (2) if creating tibial tunnels using these landmarks reduces individual variation and improves reproducibility in double-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: We retrospectively reviewed data of patients who chronologically underwent double-bundle ACL reconstruction by either referencing the footprint after remnant dissection (non-AL group) or subsequently with the ALs (AL group). Using operative videos, 3 independent observers judged whether they could confirm 6 ALs (medial intercondylar ridge, medial and lateral intercondylar tubercles, anterior horn of lateral meniscus, Parsons' knob, and L-shaped ridge) in 20 patients randomly selected from the AL group. We then compared tunnel positions between the 2 groups, measured from the anterior and medial borders of the proximal tibia and expressed as percentage of the total depth and width of the proximal tibia using 3-dimensional computed tomography. RESULTS: One hundred four patients (non-AL group, n = 54; AL group, n = 50) were included. All 6 ALs were arthroscopically confirmed in most cases (89.7% to 100%). The mean percentages of the anteroposterior (AP) depth for anteromedial (AM) tunnel, mediolateral (ML) width for AM tunnel, AP depth for posterolateral (PL) tunnel, and ML width for PL tunnel, respectively, were 27.8% ± 6.6%, 46.7% ± 2.8%, 41.4% ± 7.3%, and 46.1% ± 2.6% for the non-AL group and 30.7% ± 4.5%, 45.7% ± 2.2%, 45.2% ± 4.5%, and 46.9% ± 2.1% for the AL group, revealing significantly less variation in the AL group compared with the non-AL group, excluding the ML width of the PL tunnel (P = .007, .046, .002, .209, respectively). CONCLUSIONS: Six landmarks could be reliably confirmed in cases with remnant preservation, and creating tibial tunnels using these landmarks were reproducible and resulted in less individual variation. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Differentiation of chemical reaction activity of various carbon nanotubes using redox potential: Classification by physical and chemical structures.

The present study systematically examined the kinetics of a hydroxyl radical scavenging reaction of various carbon nanotubes (CNTs) including double-walled and multi-walled carbon nanotubes (DWCNTs and MWCNTs), and carbon nano peapods (AuCl3@DWCNT). The theoretical model that we recently proposed based on the redox potential of CNTs was used to analyze the experimental results. The reaction kinetics for DWCNTs and thin MWCNTs agreed well with the theoretical model and was consistent with each other. On the other hand, thin and thick MWCNTs behaved differently, which was consistent with the theory. Additionally, surface morphology of CNTs substantially influenced the reaction kinetics, while the doped particles in the center hollow parts of CNTs (AuCl3@DWCNT) shifted the redox potential in a different direction. These findings make it possible to predict the chemical and biological reactivity of CNTs based on the structural and chemical nature and their influence on the redox potential.

Radical scavenging reaction kinetics with multiwalled carbon nanotubes.

Progress in the development of carbon nanotubes (CNTs) has stimulated great interest among industries providing new applications. Meanwhile, toxicological evaluations on nanomaterials are advancing leading to a predictive exposure limit for CNTs, which implies the possibility of designing safer CNTs. To pursue safety by design, the redox potential in reactions with CNTs has been contemplated recently. However, the chemical reactivity of CNTs has not been explored kinetically, so that there is no scheme to express a redox reaction with CNTs, though it has been investigated and reported. In addition, the reactivity of CNTs is discussed with regard to impurities that consist of transition metals in CNTs, which obfuscates the contribution of CNTs to the reaction. The present work aimed at modeling CNT scavenging in aqueous solution using a kinetic approach and a simple first-order reaction scheme. The results show that CNTs follow the redox reaction assumption in a simple chemical system. As a result, the reaction with multiwalled CNTs is semi-quantitatively denoted as redox potential, which suggests that their biological reactions may also be evaluated using a redox potential scheme.

Calcium-mediated zoledronate loading onto carbon nanohorns.

Previously, we showed that the anti-osteoclast effect of zoledronate (ZOL), a type of bisphosphonate, is enhanced when it is used as a nanocomposite comprising ZOL, an "oxidized single-walled carbon nanohorn (OxCNH) with a spherical shape" and calcium phosphate (CaP). This nanocomposite, termed OxCNH-CaP-ZOL, is a potential therapeutic agent for patients with bone fragility associated with metastatic bone cancer. Because OxCNH-CaP-ZOL contains by-products that comprise CaP-ZOL nanocomposites, the aim of this study was to prepare more sophisticated nanocomposites lacking such by-products; it was achieved by reducing the availability of calcium and phosphate ions during the preparation process. In this new nanocomposite, ZOL loading onto OxCNH was mediated by Ca, and therefore it is referred to as OxCNH-Ca-ZOL. Because the amount of ZOL in OxCNH-Ca-ZOL was about half that in OxCNH-CaP-ZOL and murine macrophages (RAW264.7 cells) took up less OxCNH-Ca-ZOL than OxCNH-CaP-ZOL, the amount of ZOL inside RAW264.7 cells exposed to OxCNH-Ca-ZOL was less than that inside cells exposed to OxCNH-CaP-ZOL. Despite this drawback, OxCNH-Ca-ZOL had suppressive effects similar to OxCNH-CaP-ZOL on the viability of RAW264.7 cells. The reason for these phenomena is not clear; however, it could be due to the differences in the ZOL release rate between OxCNH-Ca-ZOL and OxCNH-CaP-ZOL. In addition, receptor activator of nuclear factor kappa-B ligand (RANKL)-induced differentiation of RAW264.7 cells into osteoclasts was suppressed by co-administration of RANKL with OxCNH-Ca-ZOL as effectively as with OxCNH-CaP-ZOL, and indeed, their effects were greater than those of free ZOL.

Bone-Regeneration Therapy Using Biodegradable Scaffolds: Calcium Phosphate Bioceramics and Biodegradable Polymers.

Calcium phosphate-based synthetic bone is broadly used for the clinical treatment of bone defects caused by trauma and bone tumors. Synthetic bone is easy to use; however, its effects depend on the size and location of the bone defect. Many alternative treatment options are available, such as joint arthroplasty, autologous bone grafting, and allogeneic bone grafting. Although various biodegradable polymers are also being developed as synthetic bone material in scaffolds for regenerative medicine, the clinical application of commercial synthetic bone products with comparable performance to that of calcium phosphate bioceramics have yet to be realized. This review discusses the status quo of bone-regeneration therapy using artificial bone composed of calcium phosphate bioceramics such as ß-tricalcium phosphate (ßTCP), carbonate apatite, and hydroxyapatite (HA), in addition to the recent use of calcium phosphate bioceramics, biodegradable polymers, and their composites. New research has introduced potential materials such as octacalcium phosphate (OCP), biologically derived polymers, and synthetic biodegradable polymers. The performance of artificial bone is intricately related to conditions such as the intrinsic material, degradability, composite materials, manufacturing method, structure, and signaling molecules such as growth factors and cells. The development of new scaffold materials may offer more efficient bone regeneration.

Three-Dimensional Modeling with Osteoblast-like Cells under External Magnetic Field Conditions Using Magnetic Nano-Ferrite Particles for the Development of Cell-Derived Artificial Bone.

The progress in artificial bone research is crucial for addressing fractures and bone defects in the aging population. However, challenges persist in terms of biocompatibility and structural complexity. Nanotechnology provides a promising avenue by which to overcome these challenges, with nano-ferrite particles (NFPs) exhibiting superparamagnetic properties. The ability to control cell positioning using a magnetic field opens up new possibilities for customizing artificial bones with specific shapes. This study explores the biological effects of NFPs on osteoblast-like cell lines (MC3T3-E1), including key analyses, such as cell viability, cellular uptake of NFPs, calcification processes, cell migration under external magnetic field conditions, and three-dimensional modeling. The results indicate that the impact of NFPs on cell proliferation is negligible. Fluorescence and transmission electron microscopy validated the cellular uptake of NFPs, demonstrating the potential for precise cell positioning through an external magnetic field. Under calcification-inducing conditions, the cells exhibited sustained calcification ability even in the presence of NFPs. The cell movement analysis observed the controlled movement of NFP-absorbing cells under an external magnetic field. Applying a magnetic field along the z-axis induced the three-dimensional shaping of cells incorporating NFPs, resulting in well-arranged z-axis directional patterns. In this study, NFPs demonstrated excellent biocompatibility and controllability under an external magnetic field, laying the foundation for innovative treatment strategies for customizing artificial bones.

Relationship between Being Overweight and Clinical Outcomes of Ablation Therapy for Hepatocellular Carcinoma under Ultrasound Guidance: A Retrospective Analysis.

This study aimed to investigate the effect of being overweight on the outcome of ablation therapy for patients with early-stage hepatocellular carcinoma (HCC). This retrospective study included 198 patients with HCC who underwent radiofrequency ablation or microwave ablation at Gunma Saiseikai Maebashi Hospital between April 2017 and December 2021. We divided the patients into two groups based on their body mass index (BMI): overweight (BMI ≥ 25 kg/m2, n = 74 (37.4%)) and non-overweight (BMI < 25 kg/m2, n = 124 (62.6%)). The technical success rates (TSRs) in the first session were 78.4% and 90.3% in overweight and non-overweight patients, respectively, with a significant difference (p = 0.03). Additional ablation therapy for residual tumors was required in 15 (20.3%) overweight and 11 (8.9%) non-overweight patients (p = 0.03), resulting in 95.9% and 99.2% TSRs at the final session, respectively, without a significant difference (p = 0.3). While local tumor progression and distant recurrence rates were not significantly different between the two groups, overall survival was better in overweight patients than in non-overweight patients (p < 0.001). Despite the potential adverse impact of being overweight on public health problems, the present findings showed the relationship between being overweight and improved survival. The negative aspects of being overweight might remain as minor technical issues in HCC patients receiving ablation therapy.

Biocompatibility Evaluation of Carbon Nanohorns in Bone Tissues.

With the advent of nanotechnology, the use of nanoparticles as drug delivery system (DDS) has attracted great interest. We aimed to apply carbon nanohorns (CNHs) as DDS in the development of new treatments for bone diseases. We evaluated the in vitro and in vivo cellular responses of CNHs in bone-related cells compared with carbon blacks (CBs), which are similar in particle size but differ in surface and structural morphologies. Although in vitro experiments revealed that both CNHs and CBs were incorporated into the lysosomes of RAW264-induced osteoclast-like cells (OCs) and MC3T3-E1 osteoblast-like cells (OBs), no severe cytotoxicity was observed. CNHs reduced the tartrate-resistant acid phosphatase activity and expression of the differentiation marker genes in OCs at noncytotoxic concentrations, whereas the alkaline phosphatase activity and differentiation of OBs increased. Under calcification of OBs, CNHs increased the number of calcified nodules and were intra- and extracellularly incorporated into calcified vesicles to form crystal nuclei. The in vivo experiments showed significant promotion of bone regeneration in the CNH group alone, with localized CNHs being found in the bone matrix and lacunae. The suppression of OCs and promotion of OBs suggested that CNHs may be effective against bone diseases and could be applied as DDS.

Application of carbon fibers to biomaterials: a new era of nano-level control of carbon fibers after 30-years of development.

Carbon fibers are state-of-the-art materials with properties that include being light weight, high strength, and chemically stable, and are applied in various fields including aeronautical science and space science. Investigation of applications of carbon fibers to biomaterials was started 30 or more years ago, and various products have been developed. Because the latest technological progress has realized nano-level control of carbon fibers, applications to biomaterials have also progressed to the age of nano-size. Carbon fibers with diameters in the nano-scale (carbon nanofibers) dramatically improve the functions of conventional biomaterials and make the development of new composite materials possible. Carbon nanofibers also open possibilities for new applications in regenerative medicine and cancer treatment. The first three-dimensional constructions with carbon nanofibers have been realized, and it has been found that the materials could be used as excellent scaffolding for bone tissue regeneration. In this critical review, we summarize the history of carbon fiber application to the biomaterials and describe future perspectives in the new age of nano-level control of carbon fibers (122 references).

Future Prospects for Clinical Applications of Nanocarbons Focusing on Carbon Nanotubes.

Over the past 15 years, numerous studies have been conducted on the use of nanocarbons as biomaterials towards such applications as drug delivery systems, cancer therapy, and regenerative medicine. However, the clinical use of nanocarbons remains elusive, primarily due to short- and long-term safety concerns. It is essential that the biosafety of each therapeutic modality be demonstrated in logical and well-conducted experiments. Accordingly, the fundamental techniques for assessing nanocarbon biomaterial safety have become more advanced. Optimal controls are being established, nanocarbon dispersal techniques are being refined, the array of biokinetic evaluation methods has increased, and carcinogenicity examinations under strict conditions have been developed. The medical implementation of nanocarbons as a biomaterial is in sight. With a particular focus on carbon nanotubes, these perspectives aim to summarize the contributions to date on nanocarbon applications and biosafety, introduce the recent achievements in evaluation techniques, and clarify the future prospects and systematic introduction of carbon nanomaterials for clinical use through practical yet sophisticated assessment methods.

Bisphosphonate type-dependent cell viability suppressive effects of carbon nanohorn-calcium phosphate-bisphosphonate nanocomposites.

In the process of bone metastasis, tumor cells spread to the bones to activate osteoclasts, which cause pathological bone resorption and destruction. Bisphosphonates (BPs) inhibit osteoclast activation to resorb bone, reducing bone pain and fracture. We previously developed a nanocomposite for potential localized treatment of bone metastasis by loading a BP compound, ibandronate, onto oxidized carbon nanohorns (OxCNHs), a next-generation drug carrier, using calcium phosphates (CaPs) as mediators to generate OxCNH-CaP-BP nanocomposites. The objective of the present study was to determine nanocomposite formation and biological properties of nanocomposites constructed from two BPs, zoledronate and pamidronate. In vitro tests using murine macrophages (RAW264.7 cells) and osteoclasts differentiated from RAW264.7 cells revealed that the resulting OxCNH-CaP-BP nanocomposites suppressed cell viability in a BP type-dependent manner and more effectively than OxCNHs or BPs alone. The mechanism for the potent and BP type-dependent suppression of cell viability by OxCNH-CaP-BP nanocomposites, based on their relative cellular uptake and reactive oxygen species generation, is also discussed. The present study supports the conclusions that BPs can be loaded onto OxCNHs using CaPs as mediators, and that OxCNH-CaP-BP nanocomposites are putative medicines for localized treatment of metastatic bone destruction.