Centrifugal Field-Flow Fractionation Enables Detection of Slight Aggregation of Nanoparticles That Impacts Their Biomedical Applications

Nanoparticles (NPs) are anticipated to be used for various biomedical applications in which their aggregation has been an important issue. However, concerns regarding slightly aggregated but apparently monodispersed NPs have been difficult to address because of a lack of appropriate evaluation methods. Here, we report centrifugal field-flow fractionation (CF3) as a powerful method for analyzing the slight aggregation of NPs, using antibody-modified gold NPs (Ab-AuNPs) prepared by a conventional protocol with centrifugal purification as a model. While common evaluation methods such as dynamic light scattering cannot detect significant signs of aggregation, CF3 successfully detects distinct peaks of slightly aggregated NPs, including dimers and trimers. Their impact on biological interactions was also demonstrated by a cellular uptake study: slightly aggregated Ab-AuNPs exhibited 1.8 times higher cellular uptake than monodispersed Ab-AuNPs. These results suggest the importance of aggregate evaluation via CF3 as well as the need for careful attention to the bioconjugation procedures for NPs.

Precise control methods of the physicochemical properties of nanoparticles for personalized medicine

Biomedical applications of nanoparticles (NPs) have attracted much attention. With the advancement of personalized medicine, researchers are now proposing the concept that the design of NPs needs to be optimized according to the individual patient. To realize this concept, an important question is how precisely we can tailor the physicochemical properties of NPs, such as size, shape, and surface chemistry, using current technology. This review discusses recent advances and challenges in the precise control of the size, shape, and surface chemistry of NPs. While control methods have advanced significantly over the past 20 years, the size, shape, and surface chemistry of currently available NPs vary by type, requiring careful selection based on the targeted disease, organ, and patient.

Injectable, shear-thinning, photocrosslinkable, and tissue-adhesive hydrogels composed of diazirine-modified hyaluronan and dendritic polyethyleneimine

In the present study, we report the first synthesis of diazirine-modified hyaluronic acid (HA-DAZ). In addition, we also produced a precursor polymer solution composed of HA-DAZ and dendritic polyethyleneimine (DPI) that showed strong shear-thinning properties. Furthermore, its viscosity was strongly reduced (i.e., from 5 × 105 mPa s at 10-3 s-1 to 6 × 101 mPa s at 103 s-1), substantially, which enhanced solution injectability using a 21 G needle. After ultraviolet irradiation at 365 nm and 6 mW cm-2, the HA-DAZ/DPI solution achieved rapid gelation, as measured using the stirring method, and its gelation time decreased from 200 s to 9 s as the total concentrations of HA-DAZ and DPI increased. Following UV irradiation, the storage modulus increased from 40 to 200 Pa. In addition, reversible sol-gel transition and self-healing properties were observed even after UV irradiation. This suggests that the HA-DAZ/DPI hydrogel was crosslinked in multiple ways, i.e., via covalent bonding between the diazirine and amine groups and via intermolecular interactions, including hydrogen bonding, electrostatic interactions, and hydrophobic interactions. A lap shear test showed that the HA-DAZ/DPI hydrogel exhibited strong adhesiveness as a fibrin glue following UV irradiation. Finally, the HA-DAZ/DPI hydrogel showed higher tissue reinforcement than fibrin glue in an ex vivo burst pressure test of the porcine esophageal mucosa.

Prevention of esophageal stenosis via in situ cross-linkable alginate/gelatin powder in a new submucosal exfoliation model in rats

Endoscopic submucosal dissection (ESD) for the treatment of esophageal mucosal lesions often leads to postoperative stenosis, causing difficulty in swallowing, known as dysphagia. In this study, we developed an in situ cross-linkable powder composed of alginate, gelatin, transglutaminase (TG), and calcium chloride ions (Ca2+), which can be administered through a 1.5 m-long and 3.2 mm-diameter endoscopic instrument channel. The powdered mixture of alginate and gelatin quickly formed a hydrogel by absorbing body fluids and was cross-linked by TG and Ca2+, which adhered ex vivo to porcine submucosal layers for over 2 weeks. In addition, we developed a new submucosal exfoliation model in rats that induced severe stenosis, similar to the ESD-induced stenosis models in clinical practice. When administered to the new rat model, the powder system effectively reduced the severity of esophageal stenosis based on body weight change monitoring, anatomical findings, and histological analysis. The body weight of the rats was maintained at the initial weight on postoperative day 14 (POD14), and epithelialization on POD7 and 14 improved to almost 100%. Additionally, collagen accumulation and the number of α-SMA-positive cells decreased due to powder administration. Therefore, these findings indicate that the in situ cross-linkable powder can prevent esophageal stenosis after ESD.

pH responsive cationic guar gum-borate self-healing hydrogels for muco-adhesion

We developed a new muco-adhesive hydrogel composed of cationic guar gum (CGG) and boric acid (BA). The CGG-BA precursor solution of 0.5-2% w/v concentration exhibited fluidity at low pH (3-5), while gelation occurred within 1 min at physiological pH (7-8) conditions. Scanning electron microscopy and Fourier-transform infrared spectroscopy results confirmed the change in physical and chemical behavior, respectively, with change in pH. The pH-responsive self-healing ability was analyzed through microscopy and rheology. CGG-BA hydrogels showed good self-healing property at pH 7.4. The in vitro biocompatibility test of the hydrogel studied using NIH3T3 and NHEK cells showed that it was non-toxic at concentrations of CGG-BA below 2% w/v. Ex vivo mucoadhesive tests confirmed the hydrogel's potential for use as a muco-adhesive. Burst pressure tests were conducted using pig esophageal mucosa and the results showed that at pH 7.4, 1% w/v CGG-BA self-healable hydrogel resisted about 8 ± 2 kPa pressure, comparable to that of Fibrin glue. This was higher than that at solution (pH 5) and brittle gel (pH 10) conditions. To confirm the good adhesive strength of the self-healable hydrogels, lap shear tests conducted, resulted in adhesive strengths measured in the range of 1.0 ± 0.5-2.0 ± 0.6 kPa, which was also comparable to fibrin glue control 1.8 ± 0.6 kPa. Hydrogel weight measurements showed that 40-80% gel lasted under physiological conditions for 10 h. The results suggest that CGG-BA hydrogel has potential as a pH responsive mucosal protectant biomaterial.

Development of a Potassium-Ion-Responsive Star Copolymer with Controlled Aggregation/Dispersion Transition

Stimuli-responsive star polymers are promising functional materials whose aggregation, adhesion, and interaction with cells can be altered by applying suitable stimuli. Among several stimuli assessed, the potassium ion (K⁺), which is known to be captured by crown ethers, is of considerable interest because of the role it plays in the body. In this study, a K⁺-responsive star copolymer was developed using a polyglycerol (PG) core and grafted copolymer arms consisting of a thermo-responsive poly(N-isopropylacrylamide) unit, a metal ion-recognizing benzo-18-crown-6-acrylamide unit, and a photoluminescent fluorescein O-methacrylate unit. Via optimization of grafting density and copolymerization ratio of grafted arms, along with the use of hydrophilic hyperbranched core, microsized aggregates with a diameter of 5.5 μm were successfully formed in the absence of K⁺ ions without inducing severe sedimentation (the lower critical solution temperature (LCST) was 35.6 °C). In the presence of K⁺ ions, these aggregates dispersed due to the shift in LCST (47.2 °C at 160 mM K⁺), which further induced the activation of fluorescence that was quenched in the aggregated state. Furthermore, macrophage targeting based on the micron-sized aggregation state and subsequent fluorescence activation of the developed star copolymers in response to an increase in intracellular K⁺ concentration were performed as a potential K⁺ probe or K⁺-responsive drug delivery vehicle.

Balance of antiperitoneal adhesion, hemostasis, and operability of compressed bilayer ultrapure alginate sponges

In surgery, both antiperitoneal adhesion barriers and hemostats with high efficiency and excellent handling are necessary. However, antiadhesion and hemostasis have been examined separately. In this study, six different ultrapure alginate bilayer sponges with thicknesses of 10, 50, 100, 200, 300, and 500 μm were fabricated via lyophilization and subsequent mechanical compression. Compression significantly enhanced mechanical strength and improved handling. Furthermore, it had a complex effect on dissolution time and contact angle. Therefore, the 100 μm compressed sponge showed the highest hemostatic activity in the liver bleeding model in mice, whereas the 200 μm sponge demonstrated the highest antiadhesion efficacy among the compressed sponges in a Pean crush hepatectomy-induced adhesion model in rats. For the first time, we systematically evaluated the effect of sponge compression on foldability, fluid absorption, mechanical strength, hemostatic effect, and antiadhesion properties. The optimum thickness of an alginate bilayer sponge by compression balances antiperitoneal adhesion and hemostasis simultaneously.

Facile and wide-range size tuning of conjugated polymer nanoparticles for biomedical applications as a fluorescent probe

Conjugated polymer nanoparticles (Pdots) are expected to be novel bioimaging and sensing probes. However, the size tuning required to control biological interactions has not been well established. Herein, we achieved a size-tunable synthesis of Pdots ranging from 30 to 200 nm by controlling the hydrolysis rate of the stabilising agent and evaluated their cellular imaging properties.

Cisplatin-Chelated Iminodiacetic Acid-Conjugated Hyaluronic Acid Nanogels for the Treatment of Malignant Pleural Mesothelioma in Mice

Malignant pleural mesothelioma (MPM) is one of the intractable cancers that require a more effective therapeutic strategy for clinical practice. Hyaluronic acid (HA) nanogels were prepared by the chelation of cisplatin (CDDP) with different molecular weights of iminodiacetic acid-conjugated hyaluronic acid (HA-IDA). The sizes of the 100, 850, and 2000 kDa HA nanogels were 33, 43, and 44 nm, respectively. MSTO-211H, a human MPM cell line, was more effective in taking up all three HA nanogels compared to AB22, a mouse MPM cell line. In addition, the 850 kDa HA nanogel showed higher anticancer activity against AB22 and MSTO-211H than 100 and 2000 kDa HA nanogels. Furthermore, all the HA nanogels showed a milder cytotoxic effect on normal Met-5A mesothelial cells compared to that exhibited by free CDDP. Finally, the 850 kDa HA nanogel was administrated intrapleurally into both the MSTO-211H xenograft and AB22 allograft mouse models of MPM using an injectable HA-based hydrogel. HA nanogels showed a significant therapeutic effect in both the xenograft and allograft models.

Intraperitoneal Administration of a Cisplatin-Loaded Nanogel through a Hybrid System Containing an Alginic Acid-Based Nanogel and an In Situ Cross-Linkable Hydrogel for Peritoneal Dissemination of Ovarian Cancer

Intraperitoneal chemotherapy demonstrates potential applicability in the treatment of peritoneally disseminated ovarian cancer because the disseminated tumors can directly receive exposure to high concentrations of anticancer drugs. However, a considerable proportion of drugs, particularly micromolecular and hydrophilic drugs, such as cisplatin (CDDP), are often excreted through glomerular filtration for a short period. To effectively deliver CDDP into peritoneally disseminated ovarian cancer tissues, we developed an alginate (AL)-based hybrid system in which a CDDP-loaded AL nanogel (AL/CDDP-nanogel) was encapsulated in an injectable AL-hydrogel cross-linked with calcium ions. This system enabled the sustained release of CDDP from the AL/CDDP-nanogel/AL-hydrogel hybrid for over a week. Herein, we constructed a peritoneally disseminated ovarian cancer mouse model using ovarian cancer cell lines with KRAS mutations (ID8-KRAS: KRAS^G12V). The AL/CDDP-nanogel/AL-hydrogel hybrid system showed significant antitumor activity in vivo. This therapy may be considered a novel strategy for the treatment of advanced-stage ovarian cancer with KRAS mutations.

Investigating the optimum size of nanoparticles for their delivery into the brain assisted by focused ultrasound-induced blood-brain barrier opening

The blood–brain barrier (BBB) has hampered the efficiency of nanoparticle delivery into the brain via conventional strategies. The widening of BBB tight junctions via focused ultrasound (FUS) offers a promising approach for enhancing the delivery of nanoparticles into the brain. However, there is currently an insufficient understanding of how nanoparticles pass through the opened BBB gaps. Here we investigated the size-dependence of nanoparticle delivery into the brain assisted by FUS-induced BBB opening, using gold nanoparticles (AuNPs) of 3, 15, and 120 nm diameter. For 3- and 15-nm AuNPs, FUS exposure significantly increased permeation across an in vitro BBB model by up to 9.5 times, and the permeability was higher with smaller diameter. However, in vivo transcranial FUS exposure in mice demonstrated that smaller particles were not necessarily better for delivery into the brain. Medium-sized (15 nm) AuNPs showed the highest delivery efficiency (0.22% ID), compared with 3- and 120-nm particles. A computational model suggested that this optimum size was determined by the competition between their permeation through opened BBB gaps and their excretion from blood. Our results would greatly contribute to designing nanoparticles for their delivery into the brain for the treatment of central nervous system diseases.

Thin film growth of CaAgAs by molecular beam epitaxy

We have grown thin films of CaAgAs by molecular beam epitaxy, which was theoretically proposed to be a topological insulator. The temperature dependence of resistivity and the carrier concentration at 4 K were similar to the reported results of bulk samples. However, the magnetoresistance exhibited a steep increase at low magnetic fields, a behavior not observed for bulk samples. This steep increase of resistivity is ascribable to the weak antilocalization effect and provides clues to the nature of the topological surface state of CaAgAs.

The Prevention of Hepatectomy-Induced Adhesions by Bilayer Sponge Composed of Ultrapure Alginate

BACKGROUND

Adhesion formation is a critical issue in surgery, particularly in hepatectomy. The present study aimed to develop a bilayer adhesion barrier comprising alginate (Alg) of different molecular weight (Mw). It was expected that a slowly dissolving layer remains on the cut surface, functioning as a physical barrier, whereas a rapidly dissolving layer widely distributes in the peritoneal cavity to prevent de novo adhesions.

METHODS

Bilayer Alg sponges were fabricated using low Mw Alg for the upper layer and high Mw Alg for the bottom layer. The dissolution behavior of each layer was evaluated in vitro in peritoneum-like environments. We constructed a Pean crush hepatectomy-induced adhesion model in rats. The effects of the bilayer sponge on cut surface and de novo adhesions were separately evaluated in terms of their extent and grade.

RESULTS

The Alg sponge layer with low Mw dissolved faster than that with high Mw in vitro. One week after the hepatectomy, although no significant decrease in adhesion extent on the cut surface was observed in rats that received Seprafilm and Interceed, treatment with Alg bilayer sponge significantly decreased the adhesion extent to 38% of that without treatment. Moreover, a significant decrease in de novo adhesion extent was observed in the Alg bilayer sponge compared with the Interceed group.

CONCLUSIONS

The Alg bilayer sponge was effective for preventing both cut surface and de novo adhesions in the rat Pean crush hepatectomy model. The simple yet functional design of the Alg bilayer sponge can facilitate its use in future clinical practice.

Thermoreversible gelation with ion-binding cross-links of variable multiplicity

Thermoreversible gelation and liquid-liquid phase separation are theoretically studied for the gels of polyfunctional molecules (polymers) whose network junctions are formed by complexation of functional groups on the polymer chains with added metal ions. Phase diagrams on the polymer/ion/solvent concentration plane, including both sol-gel transition lines and liquid-liquid phase separation lines (spinodals), are derived as functions of the polymer functionality, molecular weight, maximum coordination number of ions, and temperature. Binding isotherms of ions are also calculated as functions of the ion concentration. Results of the calculated sol-gel transition lines are compared with our recent experimental data on gelation of star block and telechelic, acrylic copolymers cross-linked by iron ions. It is shown that, owing to reaction stoichiometry, there is an optimal ion concentration at which the solution gels for the lowest polymer concentration and also that a re-entrant sol phase appears in the ion concentrations higher than the optimal one. The effect of stepwise complex formation constants on the re-entrant phase is studied in detail.

Characterizing the protein corona of sub-10 nm nanoparticles

Studies into the interactions of serum proteins with nanoparticles are typically performed using nanoparticles that are larger than the size of proteins. Due to this size discrepancy, adsorbed proteins are commonly depicted as a globular structure surrounding a nanoparticle. Here, we asked how we should view nanoparticle-protein complexes when the nanoparticles are of similar size or smaller than the proteins with which they interact. We showed that nanoparticles can serve as a cargo on a protein rather than as a carrier of the protein in a size-dependent manner. This can occur when nanoparticles are below 10 nm in diameter. We discovered that when the nanoparticle is a cargo on the protein, the binding of the protein to the receptor target is minimally affected in contrast to the nanoparticle serving as a carrier. Our study should change how we view and describe nanoparticle-protein complexes when the nanoparticles involved are equal in size or smaller than proteins.

Size-Controlled Preparation of Microsized Perfluorocarbon Emulsions as Oxygen Carriers via the Shirasu Porous Glass Membrane Emulsification Technique

We have developed microsized perfluorocarbon (PFC) emulsions with different sizes as artificial oxygen carriers (OCs) via Shirasu porous glass membrane emulsification. Monodispersed PFC emulsions with narrow size distribution were obtained. By changing the membrane pore size, we were able to precisely control the size of emulsions and fabricate emulsions similar in size to human red blood cells. Behaviors of Pluronics with different physiochemical properties (F127, F68, P85, and P103) as surfactants were also investigated, which evidenced that the type and concentration of Pluronics have a major impact on the size of emulsions and the response to different thermal conditions. The F127-stabilized microsized PFC emulsions were stable even during autoclave sterilization. The emulsions were loaded with Ru(ddp)-an oxygen-sensitive probe-on their surfaces to indicate oxygen concentration. Finally, incubations with HeLa cells that show fluorescence in response to hypoxia cultured in 2D and 3D suggested promising potential of our emulsions for OCs.

Bone regeneration by calcium phosphate-loaded carboxymethyl cellulose nonwoven sheets in canine femoral condyle defects

The bone regeneration capacities of calcium phosphate (CaP)-loaded carboxymethyl cellulose (CMC) nonwoven sheet (CMC/CaP) were evaluated using a dog lateral femoral condyle defect model. In addition, the effect of bFGF on bone regeneration when added to CMC/CaP sheet was investigated. The CMC and CMC/CaP sheets have high operability. The new bone formation rate in the CMC/CaP group was significantly higher than that in the control and CMC groups based on micro-computed tomography and histological evaluation. In contrast, there was no significant difference between the CMC/CaP group and the CMC/CaP/f group. In conclusion, the CMC/CaP sheet has the ability to promote new bone formation and seems to be useful as a sheet-shaped bone graft substitute. The effect of the auditioning signaling molecules to the CMC/CaP sheet, such as bFGF, requires further investigation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1516-1521, 2019.

Si-based Mach-Zehnder wavelength/mode multi/demultiplexer for a WDM/MDM transmission system

We propose and experimentally demonstrate a low-loss and low-crosstalk Mach-Zehnder mode/wavelength multi/demultiplexer for WDM/MDM transmission based on a Si-photonics platform. A broadband 3-dB mode divider, which is also newly devised here, makes it possible to compose a Mach-Zehnder filter for "mode" and "wavelength" simultaneously. Transmission characteristics of fabricated 3-dB mode dividers are in excellent agreement with theoretical results. Mach-Zehnder filters using the 3-dB mode divider with a free spectral range (FSR) of 20 and 1 nm are also fabricated and the modal crosstalk is less than -24 dB in the 40-nm wavelength range for the MZ filter with an FSR of 20 nm. The tuning of the peak wavelength position by the TiN heater is also demonstrated.

IgE sensitization to food allergens and airborne allergens in relation to biomarkers of type 2 inflammation in asthma

BACKGROUND

We have recently reported that sensitization to food allergens and sensitization to airborne allergens had independent associations with increased fraction of exhaled nitric oxide (FeNO) and blood eosinophils in middle-aged adults and in young subjects with asthma.

OBJECTIVE

To investigate the relation between IgE sensitization and several type 2 inflammation biomarkers in adult asthmatics.

METHODS

FeNO, urinary eosinophil-derived neurotoxin (U-EDN), serum eosinophil cationic protein (S-ECP) and periostin were measured in 396 asthmatics, aged 17-76 years, from the Swedish GA2LEN study. Sensitization to airborne allergens was examined with skin prick tests (≥3 mm wheal) and sensitization to food allergens with measurement of specific IgE (≥0.35 kU/L).

RESULTS

Asthmatics sensitized to food allergens had higher FeNO, 22.3 ppb (18.6, 26.7) vs 16.1 ppb (14.2, 18.2) (P = .005), S-ECP, 17.7 mg/L (14.8, 21.1) vs 12.8 mg/L (10.9, 14.9) (P = .01), and periostin, 73.7 (67.5, 80.3) ng/mL vs 59.9 (55.8, 64.2) ng/mL (P = .003), than non-sensitized subjects. Periostin levels in this group were also significantly higher than in the group sensitized only to airborne allergens (P = .01). Sensitization to food allergens related independently to FeNO (P = .02), S-ECP (P = .006) and periostin (P = .004), whereas sensitization only to airborne allergens related only to FeNO (P = .02) after adjustments for age, sex, height, weight and smoking history. FeNO correlated weakly with S-ECP (r = .17, P < .001), periostin (r = .19, P < .001) and U-EDN (0.16, P < .001). S-ECP also correlated weakly with U-EDN (r = .12, P = .02). None of the correlations between the remaining pairs of markers of type 2 inflammation were significant.

CONCLUSIONS & CLINICAL RELEVANCE

Sensitization to food allergens related to several local and systemic type 2 inflammation markers, such as FeNO, S-ECP and periostin. Assessing the profile of allergic sensitization, including to food allergens, might improve the understanding and interpretation of inflammatory markers and potentially improve asthma management.

Prospective predictors of exacerbation status in severe asthma over a 3-year follow-up

BACKGROUND

A predisposition to exacerbations is being recognized as a distinct phenotype with "previous exacerbations" representing the strongest clinical factor associated with future exacerbation. Thus, to identify additional novel biomarkers associated with asthma exacerbations, "past exacerbation status" must be included as a confounding factor.

OBJECTIVE

This study aimed to characterize the clinical and biomarker features associated with asthma exacerbations in severe asthma.

METHODS

We evaluated clinical parameters from 105 severe asthmatics yearly for 3 years, as well as their exacerbation status. We classified the subjects into 3 groups: (i) consistent non-exacerbators (CNE, subjects who did not experience any exacerbation over the 3-year period); (ii) consistent frequent exacerbators (CFE, subjects with frequent exacerbation, defined as those who had 2 or more exacerbations within 1 year, throughout the 3-year period); and (iii) intermittent exacerbators (IE). We conducted multivariate analysis for comparisons among the groups for multiple factors, including several Th2-related biomarkers, in addition to the "past exacerbation status."

RESULTS

Thirty-nine subjects were classified as CNE, 15 as CFE, and 51 as IE. Frequent exacerbations in the previous year predicted exacerbations for the following year (P < .001). Among the several Th2-related biomarkers, only FeNO was associated with exacerbation status. When we analysed the data after the second visit, the impact of FeNO on predicting future exacerbation remained significant, even after considering the exacerbation status during the first year (P < .05).

CONCLUSIONS AND CLINICAL RELEVANCE

Measurement of FeNO has a significant potential to predict future asthma exacerbation, which is independent of the "past exacerbation history."

Serum periostin relates to type-2 inflammation and lung function in asthma: Data from the large population-based cohort Swedish GA(2)LEN

BACKGROUND

Periostin has been suggested as a novel, phenotype-specific biomarker for asthma driven by type 2 inflammation. However, large studies examining relationships between circulating periostin and patient characteristics are lacking and the suitability of periostin as a biomarker in asthma remains unclear.

AIM

To examine circulating periostin in healthy controls and subjects with asthma from the general population with different severity and treatment profiles, both with and without chronic rhinosinusitis (CRS), in relation to other biomarkers and clinical characteristics.

METHODS

Serum periostin was examined by ELISA in 1100 subjects aged 17-76 from the Swedish Global Allergy and Asthma European Network (GA(2)LEN) study, which included 463 asthmatics with/without chronic rhinosinusitis (CRS), 98 individuals with CRS only, and 206 healthy controls. Clinical tests included measurement of lung function, Fraction of exhaled NO (FeNO), IgE, urinary eosinophil-derived neurotoxin (U-EDN), and serum eosinophil cationic protein (S-ECP), as well as completion of questionnaires regarding respiratory symptoms, medication, and quality of life.

RESULTS

Although median periostin values showed no differences when comparing disease groups with healthy controls, multiple regression analyses revealed that periostin was positively associated with higher FeNO, U-EDN, and total IgE. In patients with asthma, an inverse relationship with lung function was also observed. Current smoking was associated with decreased periostin levels, whereas increased age and lower body mass index (BMI) related to higher periostin levels in subjects both with and without asthma.

CONCLUSION

We confirm associations between periostin and markers of type 2 inflammation, as well as lung function, and identify novel constitutional factors of importance to the use of periostin as a phenotype-specific biomarker in asthma.

Pancreatoduodenectomy with portal vein resection for distal cholangiocarcinoma

BACKGROUND

Little is known about the value of portal vein (PV) resection in distal cholangiocarcinoma. The aim of this study was to evaluate the clinical significance of PV resection in distal cholangiocarcinoma.

METHODS

Patients who underwent pancreatoduodenectomy (PD) for distal cholangiocarcinoma between 2001 and 2010 at one of 31 hospitals in Japan were reviewed retrospectively with special attention to PV resection. Short- and long-term outcomes were evaluated.

RESULTS

In the study interval, 453 consecutive patients with distal cholangiocarcinoma underwent PD, of whom 31 (6·8 per cent) had combined PV resection. The duration of surgery (510 versus 427 min; P = 0·005) and incidence of blood transfusion (48 versus 30·7 per cent; P = 0·042) were greater in patients who had PV resection than in those who did not. Postoperative morbidity and mortality were no different in the two groups. Several indices of tumour progression, including high T classification, lymphatic invasion, perineural invasion, pancreatic invasion and lymph node metastasis, were more common in patients who had PV resection. Consequently, the incidence of R1/2 resection was higher in this group (32 versus 11·8 per cent; P = 0·004). Survival among the 31 patients with PV resection was worse than that for the 422 patients without PV resection (15 versus 42·4 per cent at 5 years; P < 0·001). Multivariable analyses revealed that age, blood loss, histological grade, perineural invasion, pancreatic invasion, lymph node metastasis and surgical margin were independent risk factors for overall survival. PV resection was not an independent risk factor.

CONCLUSION

PV invasion in distal cholangiocarcinoma is associated with locally advanced disease and several negative prognostic factors. Survival for patients who have PV resection is poor even after curative resection.

Population of the temperate mosquito, Culex pipiens, decreases in response to habitat climatological changes in future

Predictions of the temporal distribution of vector mosquitoes are an important issue for human health because the response of mosquito populations to climate change could have implications for the risk of vector-borne diseases. To elucidate the effects of climate change on mosquito populations inhabiting temperate regions, we developed a Physiology-based Climate-driven Mosquito Population model for temperate regions. For accurately reproducing the temporal patterns observed in mosquito populations, the key factors were identified by implementing the combinations of factors into the model. We focused on three factors: the effect of diapause, the positive effect of rainfall on larval carrying capacity, and the negative effect of rainfall as the washout mortality on aquatic stages. For each model, parameters were calibrated using weekly observation data of a Culex pipiens adult population collected in Tokyo, Japan. Based on its likelihood value, the model incorporating diapause, constant carrying capacity, and washout mortality was the best to replicate the observed data. By using the selected model and applying global climate model data, our results indicated that the mosquito population would decrease and adults' active season would be shortened under future climate conditions. We found that incorporating the washout effect in the model settings or not caused a difference in the temporal patterns in the projected mosquito populations. This suggested that water resources in mosquito habitats in temperate regions should be considered for predicting the risk of vector-borne diseases in such regions.

IL4Rα and ADAM33 as genetic markers in asthma exacerbations and type-2 inflammatory endotype

BACKGROUND

Genetic markers of susceptibility to asthma exacerbations in adults remain unclear.

OBJECTIVE

To identify genetic markers of asthma exacerbations, particularly in patients with type-2 inflammatory endotype.

METHODS

In this observational study of patients enrolled in the Kinki Hokuriku Airway disease Conference multicenter study, frequency of exacerbations requiring systemic corticosteroids during 2 years after enrolment and associated risk factors was determined. For genetic marker analysis, interleukin-4 receptor α (IL4RA) rs8832 and a disintegrin and metalloprotease 33 (ADAM33) S_2 (rs528557), T_1 (rs2280091), T_2 (rs2280090), and V_4 (rs2787094) variants were included. Elevated serum periostin levels at enrolment (≥95 ng/mL, defined as type-2 inflammatory endotype) were considered in the analysis.

RESULTS

Among 217 patients who were successfully followed up for 2 years after enrolment, 60 patients showed at least one asthma exacerbation during the 2 years. Airflow limitation (%FEV₁ <80%) and recent exacerbations but not genetic variants were identified as risk markers of exacerbations. A total of 27 patients showed type-2 inflammatory endotype (serum periostin ≥95 ng/mL at enrolment) and subsequent exacerbations; risk factors in these patients were airflow limitation (odds ratio, 6.51; 95% confidence interval (CI): 2.37-18.6; P=.0003), GG genotype of IL4RA rs8832 (odds ratio, 4.01; 95% CI: 1.47-11.0; P=.007), and A allele of ADAM33 T_2 (odds ratio, 2.81; 95% CI: 1.05-7.67; P=.04) by multivariate analysis. In addition, GG genotype of IL4RA rs8832 was associated with type-2 endotype, whereas A allele of ADAM33 T_2 was associated with mixed type of eosinophilic/type-2 and neutrophilic inflammations.

CONCLUSIONS AND CLINICAL RELEVANCE

IL4RA and ADAM33 variants may be risk markers of asthma exacerbations in type-2 inflammatory endotype. Precise endotyping may facilitate the identification of genetic risk markers of asthma exacerbations.

Abstract P1-03-03: High concordance of ER, PR, HER2 and Ki67 by central IHC and FISH with mRNA measurements by GeneXpert® breast cancer stratifier assay

Current methods for the assessment of ER, PR, Her2, and Ki67 using FFPE tissues are hard to standardize and difficult to perform in Low and Middle Income Countries (LMIC). The GeneXpert® breast cancer stratifier assay (RUO) (BC Strat) is a cartridge-based, RT-qPCR assay of ESR1, PGR, ERBB2, and MKi67 mRNAs using FFPE specimens. The assay is fast (&lt;2 hours, including &lt;10 minutes of hands-on time) and easy to perform.

The aims of this study were: 1) to evaluate the concordance of BC Strat using different IHC antibodies and scoring methods in a preliminary dataset (Part I); and 2) to assess concordance between BC Strat and high quality standard methods in an expanded dataset (Part II).

Methods

Part I: IHC Antibody Variability

To assess BC Strat concordance with various IHC antibodies, 155 invasive ductal carcinoma blocks were sourced from 3 sites. Twenty-four adjacent slide sections from each block were prepared and shipped to different labs for BC Strat analysis(Cepheid) or IHC and FISH testing. Table 1 summarizes the IHC antibodies and scoring methods used in each reference lab.

Table 1:IHC antibodies and scoring methods used in reference labs Antibody for IHClabIHC scoringERSP1MPLNAutomated (Aperio)ER6F11Path IncAutomated (Aperio)ER6F11USCManualPRIE2MPLNAutomated (Aperio)PR16Path IncAutomated (Aperio)PRPGR636USCManualHer2*4B5MPLNAutomated (Aperio)Her2*HercepTestUSCManualKi6730-9MPLNAutomated (Aperio)Ki67MIB1Path IncAutomated (Aperio)Ki67MIB1USCManual*HER2 FISH (all with PathVysion kit) was performed at USC

Part II: Concordance Study

522 invasive ductal carcinoma FFPE samples were sourced from 5 sites. All BC Strat analysis was performed at Cepheid and all IHC and FISH was performed in the Press laboratory at USC. Overall percent agreement (OPA), positive percent agreement (PPA), and negative percent agreement (NPA) between BC Strat and IHC were determined.

Results

Part I: IHC Antibody Variability

Table 2 summarizes the OPA for BC Strat analysis and IHC performed with different IHC antibodies and scoring methods. Slightly better concordance for ER and PR was observed between the BC Strat and the IHC methods performed at USC. Discordant IHC results were also observed among the reference labs' standard methodologies.

Table 2: Overall Percent Agreement between IHC and BC Strat Reference LabOPA with BC StratERMPLN92%ERPath Inc96%ERUSC98%PRMPLN84%PRPath Inc83%PRUSC87%Her2*MPLN*93%Her2*USC*91%Ki67MPLN75%Ki67Path Inc67%Ki67USC81%*for IHC 2+(equivocal), FISH HER2/CEP17 ratio was examined

Part II: Concordance Study

Of the 522 samples tested, 499 (96%) yielded valid results for both BC Strat and IHC (IHC and FISH for Her2). OPA between BC Strat and IHC was 98% for ESR1, 91% for PGR, 93% for ERBB2 (IHC and FISH, 97% for Her2 IHC excluding IHC2+), and 81% for MKi67.

Conclusion

BC Strat assay measurements for ESR1, PGR, ERBB2 and MKi67 mRNA expression in FFPE breast tumor tissues are highly concordant with IHC and FISH performed by high quality reference labs. Further investigations using clinical outcomes from independent studies including prospective-retrospective clinical trials are in progress.

Citation Format: Wu NC, Wong W, Ho KE, Chu VC, Rizo A, Davonport S, Kelly D, Makar R, Jassem J, Duchnowska R, Biernat W, Radecka B, Fujita T, Klein JL, Stonecypher M, Ohta S, Juhl H, Weidler JM, Bates M, Press MF. High concordance of ER, PR, HER2 and Ki67 by central IHC and FISH with mRNA measurements by GeneXpert® breast cancer stratifier assay [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-03.

3D inkjet printing of star block copolymer hydrogels cross-linked using various metallic ions

We have, for the first time, investigated 3D inkjet printing of ionically cross-linked star block copolymer hydrogels.

Utility of serum periostin and free IgE levels in evaluating responsiveness to omalizumab in patients with severe asthma

BACKGROUND

Omalizumab, a humanized anti-IgE monoclonal antibody, has demonstrated efficacy in patients with severe allergic asthma. However, treatment responses vary widely among individuals. Despite a lack of data, free serum IgE levels following omalizumab treatment have been proposed as a marker of treatment responsiveness.

METHODS

In this prospective, observational study, we assessed the utility of biomarkers of type 2 inflammation in predicting omalizumab treatment responses, as determined by the absence of asthma exacerbation during the first year of treatment. Free serum IgE levels were monitored for 2 years to examine their association with baseline biomarker levels and the number of exacerbations.

RESULTS

We enrolled thirty patients who had been treated with omalizumab for at least 1 year, of whom 27 were treated for 2 years. Baseline serum periostin levels and blood eosinophil counts were significantly higher in patients without exacerbations during the first year of treatment than in patients with exacerbations. Baseline serum periostin levels, but not eosinophil counts, were negatively associated with free serum IgE levels after 16 or 32 weeks of treatment. Reduced free serum IgE levels during treatment from those at baseline were associated with reduced exacerbation numbers at 2 years. In 14 patients who continued to have exacerbations during the first year of treatment, exacerbation numbers gradually and significantly decreased over the 2-year study period, with concurrent significant reductions in free serum IgE levels.

CONCLUSION

Baseline serum periostin levels and serum free IgE levels during treatment follow-up may be useful in evaluating responses to omalizumab treatment.

Elevation of serum squamous cell carcinoma antigen 2 in patients with psoriasis: associations with disease severity and response to the treatment

BACKGROUND

Squamous cell carcinoma antigen (SCCA) belongs to the ovalbumin-serpin family and is a known tumour marker. Expression of SCCA is upregulated in the serum and skin of patients with psoriasis.

OBJECTIVES

The aim of this study was to determine SCCA2 levels in association with disease severity and treatment efficacy in patients with psoriasis.

MATERIALS AND METHODS

Patients with psoriasis (n = 123) and healthy controls (n = 25) were enrolled in this prospective cross-sectional study. Enzyme-linked immunosorbent assay (ELISA) analysis was performed to determine serum SCCA2 levels. SCCA2 expression in skin was evaluated using immunohistochemical analysis. Serum SCCA2 levels were compared with Psoriasis Area Severity Index (PASI) scores. The effect of treatment on serum SCCA2 levels was assessed using serial examinations. Induction of SCCA2 by several psoriatic cytokines in human keratinocytes was evaluated.

RESULTS

The serum levels of SCCA2 were significantly higher in patients with psoriasis than healthy controls and correlated well with disease severity. Increased SCCA2 staining was observed in lesional skin but not in nonlesional skin of patients with psoriasis. In addition, SCCA2 expression levels in skin correlated with serum concentrations of SCCA2. SCCA2 significantly decreased according to improvement of PASI scores. Interleukin (IL)-17 and IL-22 synergistically increased the production of SCCA2 at both mRNA and protein levels in human keratinocytes.

CONCLUSIONS

Significant elevation of SCCA2 is associated with disease severity and reflects treatment efficacy. SCCA2 may be a useful biomarker in psoriasis, reflecting T-helper 17-type inflammation - the main determinant of the severity of psoriasis.