TGF-β1 Drives Integrin-Dependent Pericyte Migration and Microvascular Destabilization in Fibrotic Disease

Interactions between endothelial cells (ECs) and mural pericytes (PCs) are critical to maintaining the stability and function of the microvascular wall. Abnormal interactions between these two cell types are a hallmark of progressive fibrotic diseases such as systemic sclerosis (also known as scleroderma). However, the role that PCs play in signaling microvascular dysfunction remains underexplored. It is hypothesized that integrin-matrix interactions contribute to PC migration from the vascular wall and conversion into interstitial myofibroblasts. Using pro-inflammatory tumor necrosis factor α (TNFα) or a fibrotic growth factor [transforming growth factor β1 (TGF-β1)], human PC inflammatory and fibrotic phenotypes were evaluated by assessing their migration, matrix deposition, integrin expression, and subsequent effects on endothelial dysfunction. Both TNFα and TGF-β1 treatment altered integrin expression and matrix protein deposition, but only fibrotic TGF-β1 drove PC migration in an integrin-dependent manner. In addition, integrin-dependent PC migration was correlated to changes in EC angiopoietin-2 levels, a marker of vascular instability. Finally, there was evidence of changes in vascular stability corresponding to disease state in human systemic sclerosis skin. This work shows that TNFα and TGF-β1 induce changes in PC integrin expression and matrix deposition that facilitate migration and reduce vascular stability, providing evidence that microvascular destabilization can be an early indicator of tissue fibrosis.

Spatial-temporal order-disorder transition in angiogenic NOTCH signaling controls cell fate specification

Angiogenesis is a morphogenic process resulting in the formation of new blood vessels from pre-existing ones, usually in hypoxic micro-environments. The initial steps of angiogenesis depend on robust differentiation of oligopotent endothelial cells into the Tip and Stalk phenotypic cell fates, controlled by NOTCH-dependent cell-cell communication. The dynamics of spatial patterning of this cell fate specification are only partially understood. Here, by combining a controlled experimental angiogenesis model with mathematical and computational analyses, we find that the regular spatial Tip-Stalk cell patterning can undergo an order-disorder transition at a relatively high input level of a pro-angiogenic factor VEGF. The resulting differentiation is robust but temporally unstable for most cells, with only a subset of presumptive Tip cells leading sprout extensions. We further find that sprouts form in a manner maximizing their mutual distance, consistent with a Turing-like model that may depend on local enrichment and depletion of fibronectin. Together, our data suggest that NOTCH signaling mediates a robust way of cell differentiation enabling but not instructing subsequent steps in angiogenic morphogenesis, which may require additional cues and self-organization mechanisms. This analysis can assist in further understanding of cell plasticity underlying angiogenesis and other complex morphogenic processes.

Polybetaine-enhanced hybrid ionomer cement shows improved total biological effect with bacterial resistance and cellular stimulation

Hybrid ionomer cements (HICs) are aesthetic polyelectrolyte cements that have been modified with a resin. The setting of HICs occurs by both monomer polymerization and an acid-base reaction. In addition, HICs contain a resin, which is substituted for water. Thus, the competition between the setting reactions and reduced water content inherently limits polysalt formation and, consequently the bioactive interactions. In this study, we explored the effects of polybetaine zwitterionic derivatives (mZMs) on the augmentation of the bioactive response of HICs. The polybetaines were homogenized into an HIC in different proportions (α, β, and γ) at 3% w/v. Following basic characterization, the bioactive response of human dental pulp stem cells (hDPSCs) was evaluated. The augmented release of the principal constituent ions (strontium, silica, and fluoride) from the HIC was observed with the addition of the mZMs. Modification with α-mZM elicited the most favorable bioactive response, namely, increased ion elution, in vitro calcium phosphate precipitation, and excellent biofouling resistance, which deterred the growth of the bridging species of Veillonella. Moreover, α-mZM resulted in a significant increase in the hDPSC response, as confirmed by a significant increase (p < 0.05) in alizarin red staining. The results of mRNA expression tests, performed using periodically refreshed media, showed increased and early peak expression levels for RUNX2, OCN, and OPN in the case of α-mZM. Based on the results of the in vitro experiments, it can be concluded that modification of HICs with polybetaine α-mZM can augment the overall biological response.

Complex effects of kinase localization revealed by compartment-specific regulation of protein kinase A activity

Kinase activity in signaling networks frequently depends on regulatory subunits that can both inhibit activity by interacting with the catalytic subunits and target the kinase to distinct molecular partners and subcellular compartments. Here, using a new synthetic molecular interaction system, we show that translocation of a regulatory subunit of the protein kinase A (PKA-R) to the plasma membrane has a paradoxical effect on the membrane kinase activity. It can both enhance it at lower translocation levels, even in the absence of signaling inputs, and inhibit it at higher translocation levels, suggesting its role as a linker that can both couple and decouple signaling processes in a concentration-dependent manner. We further demonstrate that superposition of gradients of PKA-R abundance across single cells can control the directionality of cell migration, reversing it at high enough input levels. Thus, complex in vivo patterns of PKA-R localization can drive complex phenotypes, including cell migration.

Improvement of the mechanical and biological properties of bioactive glasses by the addition of zirconium oxide (ZrO2 ) as a synthetic bone graft substitute

In this study, mechanical properties of bioactive glass (BAG) synthetic bone graft substitute was improved by containing ZrO2 (ZrO2 -BAG), while maintaining advantageous biological properties of BAG such as osteoinductive and osteoconductive properties. The ZrO2 -BAG was produced by adding ZrO2 in the following proportions to replace Na2 O in 45S5 BAG: 1% (Zr1-BAG), 3% (Zr3-BAG), 6% (Zr6-BAG), and 12% (Zr12-BAG). Properties including XRD, XPS, SEM, DSC, fracture toughness, and Vickers microhardness were evaluated. To assess the biological properties, Ca/P apatite formation, ion release, degradation rate, cell proliferation, ALP activity (ALP), and alizarin red S staining assay (ARS) were evaluated. Also, expression of osteogenic differentiation markers, Osteopontin (OPN), confirmed by immunofluorescence staining. Finally, an in vivo test was carried out to by implanting ZrO2 -BAG into the subcutaneous tissue of rats. The results of each test were statistically analyzed with one-way ANOVA followed by Tukey's post hoc statistical test. Amorphous ZrO2 -BAG was successfully produced with increased mechanical properties as the ZrO2 content was increased. Additionally, ZrO2 -BAG exhibited a slower ion release and degradation rate compare to BAG without ZrO2 . Bioactivity of ZrO2 -BAG was confirmed with apatite layer formed on the surface, significantly higher proliferation rate and significantly enhanced ALP and the degree of ARS of the cells compare to respective controls. The tissue reactions observed in the in vivo study showed neo-formed vessels after implantation of ZrO2 -BAG.

Physical, Chemical, Mechanical, and Biological Properties of Four Different Commercial Root-End Filling Materials: A Comparative Study

Commercial mineral trioxide aggregate (MTA) materials such as Endocem MTA (EC), Dia-Root Bio MTA (DR), RetroMTA (RM), and ProRoot MTA (PR) are increasingly used as root-end filling materials. The aim of this study was to assess and compare the physicochemical and mechanical properties and cytotoxicity of these MTAs. The film thicknesses of EC and DR were considerably less than that of PR; however, RM’s film thickness was greater than that of PR. In addition, the setting times of EC, DR, and RM were shorter than that of PR (p < 0.05). The solubility was not significantly different among all groups. The three relatively new MTA groups (EC, DR, and RM) exhibited a significant difference in pH variation and calcium ion release relative to the PR group (p < 0.05). The radiopacity of the three new MTAs was considerably less than that of PR. The mechanical strength of RM was not significantly different from that of PR (p > 0.05); however, the EC and DR groups were not as strong as PR (p < 0.05). All MTA groups revealed cytocompatibility. In conclusion, the results of this study confirmed that EC, RM, DR, and PR exhibit clinically acceptable physicochemical and mechanical properties and cell cytotoxicity.

Osteogenic Properties of Novel Methylsulfonylmethane-Coated Hydroxyapatite Scaffold

Despite numerous advantages of using porous hydroxyapatite (HAp) scaffolds in bone regeneration, the material is limited in terms of osteoinduction. In this study, the porous scaffold made from nanosized HAp was coated with different concentrations of osteoinductive aqueous methylsulfonylmethane (MSM) solution (2.5, 5, 10, and 20%) and the corresponding MH scaffolds were referred to as MH2.5, MH5, MH10, and MH20, respectively. The results showed that all MH scaffolds resulted in burst release of MSM for up to 7 d. Cellular experiments were conducted using MC3T3-E1 preosteoblast cells, which showed no significant difference between the MH2.5 scaffold and the control with respect to the rate of cell proliferation (p > 0.05). There was no significant difference between each group at day 4 for alkaline phosphatase (ALP) activity, though the MH2.5 group showed higher level of activity than other groups at day 10. Calcium deposition, using alizarin red staining, showed that cell mineralization was significantly higher in the MH2.5 scaffold than that in the HAp scaffold (p < 0.0001). This study indicated that the MH2.5 scaffold has potential for both osteoinduction and osteoconduction in bone regeneration.

Pericytes enable effective angiogenesis in the presence of proinflammatory signals

Angiogenesis frequently occurs in the context of acute or persistent inflammation. The complex interplay of proinflammatory and proangiogenic cues is only partially understood. Using an experimental model, permitting exposure of developing blood vessel sprouts to multiple combinations of diverse biochemical stimuli and juxtacrine cell interactions, we present evidence that a proinflammatory cytokine, tumor necrosis factor (TNF), can have both proangiogenic and antiangiogenic effects, depending on the dose and the presence of pericytes. In particular, we find that pericytes can rescue and enhance angiogenesis in the presence of otherwise-inhibitory high TNF doses. This sharp switch from proangiogenic to antiangiogenic effect of TNF observed with an escalating dose of this cytokine, as well as the effect of pericytes, are explained by a mathematical model trained on the biochemical data. Furthermore, this model was predictive of the effects of diverse combinations of proinflammatory and antiinflammatory cues, and variable pericyte coverage. The mechanism supports the effect of TNF and pericytes as modulating signaling networks impinging on Notch signaling and specification of the Tip and Stalk phenotypes. This integrative analysis elucidates the plasticity of the angiogenic morphogenesis in the presence of diverse and potentially conflicting cues, with immediate implications for many physiological and pathological settings.

3D Analysis of Multi-cellular Responses to Chemoattractant Gradients

Various limitations of 2D cell culture systems have sparked interest in 3D cell culture and analysis platforms, which would better mimic the spatial and chemical complexity of living tissues and mimic in vivo tissue functions. Recent advances in microfabrication technologies have facilitated the development of 3D in vitro environments in which cells can be integrated into a well-defined extracellular matrix (ECM) and a defined set of soluble or matrix associated biomolecules. However, technological barriers have limited their widespread use in research laboratories. Here, we describe a method to construct simple devices for 3D culture and experimentation with cells and multicellular organoids in 3D microenvironments with a defined chemoattractant gradient. We illustrate the use of this platform for analysis of the response of epithelial cells and organoids to gradients of growth factors, such as epidermal growth factor (EGF). EGF gradients were stable in the devices for several days leading to directed branch formation in breast organoids. This analysis allowed us to conclude that collective gradient sensing by groups of cells is more sensitive vs. single cells. We also describe the fabrication method, which does not require photolithography facilities nor advanced soft lithography techniques. This method will be helpful to study 3D cellular behaviors in the context of the analysis of development and pathological states, including cancer.

Glutathione S-transferase genotype and risk of systemic lupus erythematosus in Koreans

Oxidative stress caused by poor detoxification efficiency of reactive oxygen species (ROS) may play a role in the development of systemic lupus erythematosus (SLE). Glutathione S-transferase (GST) is involved in the detoxification of ROS and genetic polymorphisms of GSTM1, GSTT1 and GSTP1 are associated with altered enzyme activity. The aim of this study was to determine whether GSTM1 (deletion), GSTT1 (deletion) and GSTP1 (Ile105! Val105) polymorphisms are associated with susceptibility to SLE or frequency of clinical manifestations according to the ACR diagnostic criteria. DNA was isolated from blood samples collected from 330 patients with SLE and 270 ageand sex-matched controls. GST genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. No associations were observed between GSTM1, GSTT1, and GSTP1 genotypes and risk of SLE. Among SLE patients, the GSTM1 null genotype was associated with a lower frequency of hematological disorders ( P = 0.012), and a higher SSA(+)/SSB(2) autoantibody profile ( P = 0.042). Compared to SLE patients with the GSTT1 non-null genotype, those with the GSTT1 null genotype had a lower frequency of discoid rash ( P = 0.018), and nephritis ( P = 0.033). Our findings suggest that genetic polymorphisms of GSTM1, GSTT1, and GSTP1 do not influence the risk of SLE, but a deletion of either GSTM1 or GSTT1 may influence certain clinical manifestations of the disease.

Evaluation of the Effective Diffusivity of a Freeform Fabricated Scaffold Using Computational Simulation

In scaffold-based tissue engineering, sufficient oxygen and nutrient supply into cells within a scaffold is essential to increase cell viability and the proliferation rate. Generally, oxygen and nutrients reach the cells through the media by diffusion in vitro or in vivo, assuming there is no convection flow through a scaffold with small-sized pores. The scaffold diffusion rate depends mainly on the scaffold pore architecture. Thus, understanding the effect of scaffold pore architecture on the diffusion mechanism is necessary to design an efficient scaffold model. This study proposes a computational method to estimate diffusivity using the finite element analysis (FEA). This method can be applied to evaluate and analyze the effective diffusivity of a freeform fabricated 3D scaffold. The diffusion application module of commercial FEA software was used to calculate the spatial oxygen concentration gradient in a scaffold model medium. The effective diffusivities of each scaffold could be calculated from the oxygen concentration data, which revealed that the scaffold pore architecture influences its effective diffusivity. The proposed method has been verified experimentally and can be applied to design pore architectures with efficient diffusion by increasing our understanding of how the diffusion rate within a scaffold is affected by its pore architecture.

Design and assessment of a microfluidic network system for oxygen transport in engineered tissue

Oxygen and nutrients cannot be delivered to cells residing in the interior of large-volume scaffolds via diffusion alone. Several efforts have been made to meet the metabolic needs of cells in a scaffold by constructing mass transport channels, particularly in the form of bifurcated networks. In contrast to progress in fabrication technologies, however, an approach to designing an optimal network based on experimental evaluation has not been actively reported. The main objective of this study was to establish a procedure for designing an effective microfluidic network system for a cell-seeded scaffold and to develop an experimental model to evaluate the design. We proposed a process to design a microfluidic network by combining an oxygen transport simulation with biomimetic principles governing biological vascular trees. The simulation was performed with the effective diffusion coefficient (D(e,s)), which was experimentally measured in our previous study. Porous scaffolds containing an embedded microfluidic network were fabricated using the lost mold shape-forming process and salt leaching method. The reliability of the procedure was demonstrated by experiments using the scaffolds. This approach established a practical basis for designing an effective microfluidic network in a cell-seeded scaffold.

Enhanced endothelialization for developing artificial vascular networks with a natural vessel mimicking the luminal surface in scaffolds

Large tissue regeneration remains problematic because of a lack of oxygen and nutrient supply. An attempt to meet the metabolic needs of cells has been made by preforming branched vascular networks within a scaffold to act as channels for mass transport. When constructing functional vascular networks with channel patency, emphasis should be placed on anti-thrombogenic surface issues. The aim of this study was to develop a rapid endothelialization method for creating an anti-thrombogenic surface mimicking the natural vessel wall in the artificial vascular networks. Shear stress preconditioning and scaffold surface modification were investigated as effective approaches for promoting biomaterial endothelialization. We found that a transient increase in shear stress at the appropriate time is key to enhancing endothelialization. Moreover, surface modification with bioactive materials such as collagen and recombinant mussel adhesive protein fused with arginine-glycine-aspartic acid peptide (MAP-RGD) showed a synergetic effect with shear stress preconditioning. Platelet adhesion tests demonstrated the anti-thrombogenic potential of MAP-RGD itself without endothelialization. The rapid endothelialization method established in this study can be easily applied to preformed artificial vascular networks in porous scaffolds. Development of artificial vascular networks with an anti-thrombogenic luminal surface will open up a new chapter in tissue engineering and regenerative medicine.

Unit cell-based computer-aided manufacturing system for tissue engineering

Scaffolds play an important role in the regeneration of artificial tissues or organs. A scaffold is a porous structure with a micro-scale inner architecture in the range of several to several hundreds of micrometers. Therefore, computer-aided construction of scaffolds should provide sophisticated functionality for porous structure design and a tool path generation strategy that can achieve micro-scale architecture. In this study, a new unit cell-based computer-aided manufacturing (CAM) system was developed for the automated design and fabrication of a porous structure with micro-scale inner architecture that can be applied to composite tissue regeneration. The CAM system was developed by first defining a data structure for the computing process of a unit cell representing a single pore structure. Next, an algorithm and software were developed and applied to construct porous structures with a single or multiple pore design using solid freeform fabrication technology and a 3D tooth/spine computer-aided design model. We showed that this system is quite feasible for the design and fabrication of a scaffold for tissue engineering.

Detection of tuberculosis using artus M. tuberculosis PCR Kit and COBAS AMPLICOR Mycobacterium tuberculosis Test

SETTING

Nucleic acid amplification tests can detect Mycobacterium tuberculosis complex rapidly and reliably.

OBJECTIVE

To compare the diagnostic performance of the artus M. tuberculosis PCR Kit and COBAS AMPLICOR Mycobacterium tuberculosis Test. In the artus assay, an appropriate cycle threshold (Ct) value was determined for positivity.

DESIGN

A total of 238 clinical respiratory specimens were analysed using both the artus and COBAS AMPLICOR assays. In 221 specimens, these results were further compared with culture results.

RESULTS

The overall agreement between artus and COBAS AMPLICOR was 96.2% (229/238). Among the nine (3.8%) discrepant specimens, three (1.3%) were artus-positive and COBAS AMPLICOR-negative, while the other six (2.5%) were artus-negative and COBAS AMPLICOR-positive. Using culture as a standard, the sensitivity and specificity of the artus assay were 97.8% and 85.1%, and those of COBAS AMPLICOR assay were 100% and 86.2%, respectively. The difference was not statistically significant. In the artus assay, the minimum Ct value for the positivity determination was 38.

CONCLUSION

The artus and COBAS AMPLICOR assays showed comparable diagnostic performance and can be confidently used for detection of M. tuberculosis complex. In the artus assay, a Ct value of 38 could be suggested as an appropriate cut-off value.

Effect of prior rituximab on high-dose therapy and autologous stem cell transplantation in follicular lymphoma

Autologous stem-cell transplantation (ASCT) has been used in follicular lymphoma (FL) to achieve durable responses in first remission or in the relapsed or refractory settings. Addition of rituximab to chemotherapy for FL has been shown to improve survival. The impact of prior therapy with rituximab upon the effectiveness of high-dose therapy (HDT) and ASCT in patients with FL is unknown. We retrospectively reviewed consecutive patients with FL who underwent HDT and ASCT. Patients were categorized according to prior therapy with rituximab. Outcomes were compared between groups in all patients and in a well-matched subset. In all 35 patients received prior rituximab and 71 rituximab-naive patients were analyzed. The rituximab-naive group had a median overall survival (OS) that was not reached during follow-up, with a median relapse-free (RFS) survival of 49.9 months. The prior rituximab group also did not reach median OS and had a median RFS of 24.6 months. Survivals were not significantly different in this group or in the well-matched subset. In conclusion, these results suggest that the use of rituximab-based regimens for the treatment of FL does not compromise the effectiveness of HDT and ASCT as a salvage strategy in patients with FL.

Muscular amyloidoma presenting as inguinal masses in multiple myeloma

We report a case with protruding inguinal masses for 6 months, in whom muscular amyloidoma was not suspected before muscle biopsy. On pelvic magnetic resonance imaging (MRI), round masses showing peripheral rim enhancement with gadolinium were observed in iliopsoas and iliacus muscles of both inguinal areas. The same lesions were also observed in gluteus muscles. The biopsy showed Congo red positive materials in a dense fibrous background. Serum and urine electrophoresis showed Bence Jones protein, lambda type. In bone marrow section, myeloma cells were found. Peripheral blood stem cell transplantation (PBSCT) following four cycles of VAD (vincristine, adriamycin, dexamethasone) chemotherapy was performed and the result was satisfactory. Amyloidoma lesions decreased in size and number on the following MRI.

Effect of blastomere sex and fluorescent labelling on the development of bovine chimeric embryos reconstituted at the four-cell stage

The development rate of bovine chimeric embryos reconstituted at the 4-cell stage is relatively low. If chimerism is to be used as an approach in producing transgenic livestock, it is important to investigate whether this rate is affected by the sex of the blastomeres being combined and if all blastomeres survive equally well. In Experiment 1, blastomeres from 4-cell stage embryos were inserted into surrogate zonae pellucidae either in pairs to reconstitute 4-cell chimeras, or as the original sets of four to make handled controls. The development of chimeras with one pair of blastomeres labelled with PKH26-GL was also investigated. The rate of development into blastocysts was similar in chimeras with unlabelled blastomeres (23%) and in those in which one pair of blastomeres was labelled (26%) and was lower (P < 0.001) than in the handled and IVF control groups (43 and 58%, respectively). Labelled cells were distributed approximately evenly between ICM and trophoblast. In Experiment 2, the effect of sex differences between pairs of blastomeres in chimeras was investigated; chimeras were reconstituted from pairs of blastomeres taken from 4-cell embryos in which the remaining pair was sexed by PCR. No significant differences according to the sex of constituent blastomeres were detectable (mixed sex, 27%; males, 24%; females, 21%; P > 0.05). These results suggest that, in addition to the negative effects of micromanipulation, factors other than the sex of the blastomeres are involved in the reduced rate of development of chimeric bovine embryos. They also confirm the usefulness of PKH26-GL labelling for tracking the progeny of cleaving bovine blastomeres at least to the blastocyst stage.

Synchronous cardiac myxoma and colorectal cancer: a case report

The occurrence of synchronous but unrelated cardiac and colorectal tumors is extremely rare. We present the case of a 56-year-old man who had a left atrial cardiac myxoma that nearly obstructed the mitral valve outflow tract and an unrelated, synchronous colorectal-vesicle carcinoma that nearly obstructed the lumen of the intestine. The patient underwent emergency resection of the cardiac mass under cardiopulmonary bypass and underwent successful resection of the colorectal mass 2 weeks later Two years after these operations, the patient is well with no recurrence of either tumor Synchronous tumors, particularly when one of them involves the heart, require aggressive surgical treatment at multiple sites in order for the patient to survive.

The effect of premarin on blood loss attending open heart surgery

Premarin was administered prophylactically to every other patient in a series of 148 consecutive cases of open intracardiac surgery. Of these, 132 patients were matched to analyse the results of Premarin administration and postoperative blood loss. There were 67 patients who were given Premarin and 65 who did not receive this drug; both groups were identical in respect of age and sex. Matching was undertaken according to history of previous cardiac operations and anticoagulation, type of valve surgery or repair of congenital anomaly, duration of perfusion, platelet count and the use of fresh blood and epsilon-aminocaproic acid in the postoperative period. The prophylactic use of Premarin was not associated with a reduction in postoperative bleeding.