Skin-brain axis in Alzheimer's disease - Pathologic, diagnostic, and therapeutic implications: A Hypothetical Review.

The dynamic interaction between the brain and the skin is termed the 'skin-brain axis.' Changes in the skin not only reflect conditions in the brain but also exert direct and indirect effects on the brain. Interestingly, the connection between the skin and brain is crucial for understanding aging and neurodegenerative diseases. Several studies have shown an association between Alzheimer's disease (AD) and various skin disorders, such as psoriasis, bullous pemphigoid, and skin cancer. Previous studies have shown a significantly increased risk of new-onset AD in patients with psoriasis. In contrast, skin cancer may reduce the risk of developing AD. Accumulating evidence suggests an interaction between skin disease and AD; however, AD-associated pathological changes mediated by the skin-brain axis are not yet clearly defined. While some studies have reported on the diagnostic implications of the skin-brain axis in AD, few have discussed its potential therapeutic applications. In this review, we address the pathological changes mediated by the skin-brain axis in AD. Furthermore, we summarize (1) the diagnostic implications elucidated through the role of the skin-brain axis in AD and (2) the therapeutic implications for AD based on the skin-brain axis. Our review suggests that a potential therapeutic approach targeting the skin-brain axis will enable significant advances in the treatment of AD.

Therapeutic Potential of Traditional Oriental Medicines in Targeting Tau Pathology: Insights from Cell-free and Cell-based Screening.

BACKGROUND: Traditional Oriental Medicines (TOMs) formulated using a variety of medicinal plants have a low risk of side effects. In previous studies, five TOMs, namely Dangguijakyaksan, Hwanglyeonhaedoktang, Ukgansan, Palmijihwanghwan, and Jowiseungchungtang have been commonly used to treat patients with Alzheimer's disease. However, only a few studies have investigated the effects of these five TOMs on tau pathology. OBJECTIVE: This study aimed to examine the effect of five TOMs on various tau pathologies, including post-translational modifications, aggregation and deposition, tau-induced neurotoxicity, and tau-induced neuroinflammation. METHODS: Immunocytochemistry was used to investigate the hyperphosphorylation of tau induced by okadaic acid. In addition, the thioflavin T assay was used to assess the effects of the TOMs on the inhibition of tau K18 aggregation and the dissociation of tau K18 aggregates. Moreover, a water-soluble tetrazolium-1 assay and a quantitative reverse transcription polymerase chain reaction were used to evaluate the effects of the TOMs on tau-induced neurotoxicity and inflammatory cytokines in HT22 and BV2 cells, respectively. RESULTS: The five TOMs investigated in this study significantly reduced okadaic acid-induced tau hyperphosphorylation. Hwanglyeonhaedoktang inhibited the aggregation of tau and promoted the dissociation of tau aggregates. Dangguijakyaksan and Hwanglyeonhaedoktang attenuated tau-induced neurotoxicity in HT22 cells. In addition, Dangguijakyaksan, Hwanglyeonhaedoktang, Ukgansan, and Palmijihwanghwan reduced tauinduced pro-inflammatory cytokine levels in BV2 cells. CONCLUSION: Our results suggest that five TOMs are potential therapeutic candidates for tau pathology. In particular, Hwanglyeonhaedoktang showed the greatest efficacy among the five TOMs in cell-free and cell-based screening approaches. These findings suggest that Hwanglyeonhaedoktang is suitable for treating AD patients with tau pathology.

Laser Rescanning for Enhancing Mechanical Properties of Laser-Directed Energy-Deposited High-Manganese Steels.

This study investigates the effects of laser deposition and laser rescanning (LR) on the microstructure and mechanical properties of high-manganese steel (HMnS) deposited by laser-directed energy deposition (L-DED) comprising 24 wt.% Mn. Four types of laser deposition and LR strategies were investigated: unidirectional L-DED scanning without laser rescanning, L-DED scanning with 90° alterations in the laser scanning path on each layer without laser rescanning, unidirectional L-DED with laser rescanning in the same direction, and L-DED with laser rescanning with 90° alterations in the laser scanning path. The L-DED-processed HMnS had only a few small pores and exhibited a microstructure without any serious defects such as cracks. Additionally, a strong fibrous texture along the <101>/building direction of the fully austenite phase was found. The mechanical properties (microhardness and tensile strength) of HMnS were improved by the LR with a grain refinement effect and fine solidification cell size due to the significantly faster solidification rate in LR than that in L-DED.

Dual regulatory effects of neferine on amyloid-ß and tau aggregation studied by in silico, in vitro, and lab-on-a-chip technology.

Alzheimer's disease (AD) is characterized by the presence of two critical pathogenic factors: amyloid-ß (Aß) and tau. Aß and tau become neurotoxic aggregates via self-assembly, and these aggregates contribute to the pathogenesis of AD. Therefore, there has been growing interest in therapeutic strategies that simultaneously target Aß and tau aggregates. Although neferine has attracted attention as a suitable candidate agent for alleviating AD pathology, there has been no study investigating whether neferine affects the modulation of Aß or tau aggregation/dissociation. Herein, we investigated the dual regulatory effects of neferine on Aß and tau aggregation/dissociation. We predicted the binding characteristics of neferine to Aß and tau using molecular docking simulations. Next, thioflavin T and atomic force microscope analyses were used to evaluate the effects of neferine on the aggregation or dissociation of Aß42 and tau K18. We verified the effect of neferine on Aß fibril degradation using a microfluidic device. In addition, molecular dynamics simulation was used to predict a conformational change in the Aß42-neferine complex. Moreover, we examined the neuroprotective effect of neferine against neurotoxicity induced by Aß and tau and their fibrils in HT22 cells. Finally, we foresaw the pharmacokinetic properties of neferine. These results demonstrated that neferine, which has attracted attention as a potential treatment for AD, can directly affect Aß and tau pathology.

Stretchable zein-coated alginate fiber for aligning muscle cells to artificially produce cultivated meat.

Numerous studies have explored the cultivation of muscle cells using non-animal materials for cultivated meat production. Achieving muscle cell proliferation and alignment using 3D scaffolds made from plant-based materials remains challenging. This study introduces a technique to culture and align muscle cells using only plant-based materials, avoiding toxic chemical modifications. Zein-alginate fibers (ZA fibers) were fabricated by coating zein protein onto alginate fibers (A fibers). Zein's excellent cell compatibility and biodegradability enable high cell adhesion and proliferation rates, and the good ductility of the ZA fibers enable a high strain rate (>75%). We demonstrate mature and aligned myotube formation in ZA fibers, providing a simple way to align muscle cells using plant-based materials. Additionally, cultivated meat was constructed by assembling muscle, fat, and vessel fibers. This method holds promise for the future mass production of cultivated meat.

Korean red ginseng polysaccharide as a potential therapeutic agent targeting tau pathology in Alzheimer's disease.

Tau is a microtubule-associated protein that plays a critical role in the stabilization and modulation of neuronal axons. Tau pathology is stronger associated with cognitive decline in patients with Alzheimer's disease (AD) than amyloid beta (Aß) pathology. Hence, tau targeting is a promising approach for the treatment of AD. Previous studies have demonstrated that the non-saponin fraction with rich polysaccharide (NFP) from Korean red ginseng (KRG) can modulate tau aggregation and exert a therapeutic effect on AD. Therefore, we investigated the efficacy of NFP isolated from KRG on tau pathology in experimental models of AD. Our results showed that NFP from KRG ameliorated deposition and hyperphosphorylation of tau in the brain of 3xTg mice. Moreover, NFP from KRG modulated the aggregation and dissociation of tau K18 in vitro. We demonstrated the alleviatory effects of NFP from KRG on hyperphosphorylated tau and tau kinase in okadaic acid-treated HT22 cells. Furthermore, NFP from KRG mitigated Aß deposition, neurodegeneration, and neuroinflammation in 3xTg mice. We revealed the neuroprotective effects of NFP from KRG on tau-induced neuronal loss in HT22 cells. Our results indicate that NFP extracted from KRG is a novel therapeutic agent for the treatment of AD associated with tau pathology.

CORM­2 reduces cisplatin accumulation in the mouse inner ear and protects against cisplatin-induced ototoxicity.

INTRODUCTION: Cisplatin is a life-saving anticancer compound used to treat multiple solid malignant tumors, while it causes permanent hearing loss. There is no known cure, and the FDA has not approved any preventative treatment for cisplatin-based ototoxicity. OBJECTIVES: This study investigated whether the carbon monoxide (CO)-releasing tricarbonyldichlororuthenium (II) dimer, CORM-2, reverses cisplatin-induced hearing impairment and reduces cisplatin accumulation in the mouse inner ear. METHODS: Male 6-week-old BALB/c mice were randomly assigned to one of the following groups: control (saline-treated, i.p.), CORM-2 only (30 mg/kg, i.p., four doses), cisplatin only (20 mg/kg, i.p., one dose), and CORM-2 + cisplatin, to determine whether cisplatin-based hearing impairment was alleviated by CORM-2 treatment. RESULTS: Our results revealed CORM-2 significantly attenuated cisplatin-induced hearing loss in young adult mice. CORM-2 co-treatment significantly decreased platinum accumulation in the inner ear and activated the plasma membrane repair system of the stria vascularis. Moreover, CORM-2 co-treatment significantly decreased cisplatin-induced inflammation, apoptosis, and cochlear necroptosis. Because the stria vascularis is the likely cochlear entry point of cisplatin, we next focused on the microvasculature. Cisplatin induced increased extravasation of a chromatic tracer (fluorescein isothiocyanate [FITC]-dextran, MW 75 kDa) around the cochlear microvessels at 4 days post-treatment; this extravasation was completely inhibited by CORM-2 co-therapy. CORM-2 co-treatment effectively maintained the integrity of stria vascularis components including endothelial cells, pericytes, and perivascular-resident macrophage-type melanocytes. CONCLUSION: CORM-2 co-therapy substantially protects against cisplatin-induced ototoxicity by reducing platinum accumulation and toxic cellular stress responses. These data indicate that CORM-2 co-treatment may be translated into clinical strategy to reduce cisplatin-induced hearing loss.

Genipin and pyrogallol: Two natural small molecules targeting the modulation of disordered proteins in Alzheimer's disease.

Alzheimer's disease (AD) is characterized by the aggregation of disordered proteins, such as amyloid beta (Aß) and tau, leading to neurotoxicity and disease progression. Despite numerous efforts, effective inhibitors of Aß and tau aggregates have not been developed. Thus, we aimed to screen natural small molecules from crude extracts that target various pathologies and are prescribed for patients with neurological diseases. In this study, we screened 162 natural small molecules prescribed for neurological diseases and identified genipin and pyrogallol as hit compounds capable of simultaneously regulating the aggregation of Aß and tau K18. Moreover, we confirmed the dual modulatory effects of these compounds on the reduction of amyloid-mediated neurotoxicity in vitro and the disassembly of preformed Aß42 and tau K18 fibrils. Furthermore, we observed the alleviatory effects of genipin and pyrogallol against AD-related pathologies in triple transgenic AD mice. Molecular dynamics and docking simulations revealed the molecular interaction dynamics of genipin and pyrogallol with Aß42 and tau K18, providing insights into their suppression of aggregation. Our findings suggest the therapeutic potential of genipin and pyrogallol as dual modulators for the treatment of AD by inhibiting aggregation or promoting dissociation of Aß and tau.

Development of cultivable alginate fibers for an ideal cell-cultivated meat scaffold and production of hybrid cultured meat.

Slaughtering animals for meat pose several challenges, including environmental pollution and ethical concerns. Scaffold-based cell-cultivated meat has been proposed as a solution to these problems, however, the utilization of animal-derived materials for scaffolding or the high cost of production remains a significant challenge. Alginate is an ideal material for cell-cultivated meat scaffolds but has poor cell adhesion properties. To address this issue, we achieved 82 % cell adhesion coverage by controlling the specific structure generated during the ionic crosslinking process of alginate. Post 11 days of culture; we evaluated cell adhesion, differentiation, and aligned cell networks. The cell growth increased by 12.7 % compared to the initial seeding concentration. Finally, we created hybrid cell-cultivated meat by combining single-cell protein from mycelium and cell-cultivated meat. This is non-animal based, edible, cost-effective, and has a desirable texture by blending cell-cultivated meat with a meat analogue. In summary, the creation of improved alginate fibers can effectively tackle various obstacles encountered in the manufacturing of cell-cultivated meat. This includes enhancing cell adhesion, reducing costs, and streamlining the production procedure.

Characterization of age- and stage-dependent impaired adult subventricular neurogenesis in 5XFAD mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline. Several recent studies demonstrated that impaired adult neurogenesis could contribute to AD-related cognitive impairment. Adult subventricular zone (SVZ) neurogenesis, which occurs in the lateral ventricles, plays a crucial role in structural plasticity and neural circuit maintenance. Alterations in adult SVZ neurogenesis are early events in AD, and impaired adult neurogenesis is influenced by the accumulation of intracellular Aß. Although Aß-overexpressing transgenic 5XFAD mice are an AD animal model well representative of Aß-related pathologies in the brain, the characterization of altered adult SVZ neurogenesis following AD progression in 5XFAD mice has not been thoroughly examined. Therefore, we validated the characterization of adult SVZ neurogenesis changes with AD progression in 2-, 4-, 8-, and 11-monthold male 5XFAD mice. We first investigated the Aß accumulation in the SVZ using the 4G8 antibody. We observed intracellular Aß accumulation in the SVZ of 2-month-old 5XFAD mice. In addition, 5XFAD mice exhibited significantly increased Aß deposition in the SVZ with age. Next, we performed a histological analysis to investigate changes in various phases of adult neurogenesis, such as quiescence, proliferation, and differentiation, in SVZ. Compared to age-matched wild-type (WT) mice, quiescent neural stem cells were reduced in 5XFAD mice from 2-11 months of age. Moreover, proliferative neural stem cells were decreased in 5XFAD mice from 2 to 8 months of age. Furthermore, differentiations of neuroblasts were diminished in 5XFAD mice from 2-11 months of age. Intriguingly, we found that adult SVZ neurogenesis was reduced with aging in healthy mice. Taken together, our results revealed that impairment of adult SVZ neurogenesis appears with aging or AD progression. [BMB Reports 2023; 56(9): 520-525].

Injectable Poloxamer Hydrogel Formulations for Intratympanic Delivery of Dexamethasone.

BACKGROUND: In this study, we prepared and evaluated an injectable poloxamer (P407) hydrogel formulation for intratympanic (IT) delivery of dexamethasone (DEX). METHODS: DEX-loaded P407 hydrogels were characterized in terms of thermogelation, drug loading capacities, particle size, and drug release. The in vivo toxicity and drug absorption of the DEX-loaded P407 formulation after IT injection were evaluated using an animal model by performing histopathological analysis and drug concentration measurements. RESULTS: The P407 hydrogel effectively solubilized hydrophobic DEX and demonstrated a sustained release compared to the hydrophilic DEX formulation. The in vivo study showed that the hydrogel formulation delivered considerable drug concentrations to the inner ear and displayed a favorable safety profile without apparent cytotoxicity or inflammation. CONCLUSION: P407 hydrogel can be useful as an injectable inner ear delivery formulation for hydrophobic drugs due to their biocompatibility, drug-solubilizing capacity, thermogelation, and controlled release.

Degree of Impurity and Carbon Contents in the Grain Size of Mg-Al Magnesium Alloys.

In this study, the tendency of having different grain structures depending on the impurity levels in AZ91 alloys was investigated. Two types of AZ91 alloys were analyzed: commercial-purity AZ91 and high-purity AZ91. The average grain size of the commercial-purity AZ91 alloy and high-purity AZ91 is 320 µm and 90 µm, respectively. Thermal analysis revealed negligible undercooling in the high-purity AZ91 alloy, while undercooling of 1.3 °C was observed in the commercial-purity AZ91 alloy. A CS analyzer was employed to precisely analyze the carbon composition of both alloys. The carbon content of the high-purity AZ91 alloy was found to be 197 ppm, while the commercial-purity AZ91 alloy contained 104 ppm, indicating a difference of approximately 2 times. The higher carbon content in the high-purity AZ91 alloy is believed to be due to the use of high-purity pure Mg in its production (the carbon content of high-purity pure Mg is 251 ppm). To simulate the vacuum distillation process commonly used in the production of high-purity Mg ingots, experiments were conducted to investigate the reaction of carbon with oxygen to produce CO and CO2. XPS analysis and simulation results for activities confirmed the formation of CO and CO2 during the vacuum distillation process. It could be speculated that the carbon sources in the high-purity Mg ingot provide Al-C particles, which act as nucleants for Mg grains in the high-purity AZ91 alloy. Thus, it can be considered the main reason that high-purity AZ91 alloys have a finer grain structure than that of commercial-purity AZ91 alloys.

Synthesis and Characterization of Al Chip-Based Syntactic Foam Containing Glass Hollow Spheres Fabricated by a Semi-Solid Process.

In this study, aluminum (Al) chip matrix-based synthetic foams were fabricated by hot pressing at a semi-solid (SS) temperature. The densities of the foams ranged from 2.3 to 2.63 g/cm3, confirming that the density decreased with increasing glass hollow sphere (GHS) content. These values were approximately 16% lower than the densities of Al chip alloys without GHS. The Al chip syntactic foam microstructure fabricated by the semi-solid process comprised GHS uniformly distributed around the Al chip matrix and a spherical microstructure surrounded by the Mg2Si phase in the interior. The resulting spherical microstructure contributed significantly to the improvement of mechanical properties. Mechanical characterization confirmed that the Al chip syntactic foam exhibited a compressive strength of approximately 225-288 MPa and an energy absorption capacity of 46-47 MJ/M3. These results indicate higher compressive properties than typical Al syntactic foam. The Al chip microstructure, consisting of the Mg2Si phase and GHS, acted as a load-bearing element during compression, significantly contributing to the compressive properties of the foam. An analysis was performed using an energy-dispersive spectrometer to validate the interfacial reaction between the GHS and the matrix. The results showed that MgAl2O4 was uniformly coated around GHS, which contributed not only to the strength of the matrix, but also to the mechanical properties via the appropriate interfacial reactive coating.

Sex differences in hearing impairment due to diet-induced obesity in CBA/Ca mice.

BACKGROUND: Obesity is an independent risk factor for hearing loss. Although attention has focused on major obesity comorbidities such as cardiovascular disease, stroke, and type 2 diabetes, the impact of obesity on sensorineural organs, including the auditory system, is unclear. Using a high-fat diet (HFD)-induced obese mouse model, we investigated the impact of diet-induced obesity on sexual dimorphism in metabolic alterations and hearing sensitivity. METHODS: Male and female CBA/Ca mice were randomly assigned to three diet groups and fed, from weaning (at 28 days) to 14 weeks of age, a sucrose-matched control diet (10 kcal% fat content diet), or one of two HFDs (45 or 60 kcal% fat content diets). Auditory sensitivity was evaluated based on the auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and ABR wave 1 amplitude at 14 weeks of age, followed by biochemical analyses. RESULTS: We found significant sexual dimorphism in HFD-induced metabolic alterations and obesity-related hearing loss. Male mice exhibited greater weight gain, hyperglycemia, increased ABR thresholds at low frequencies, elevated DPOAE, and lower ABR wave 1 amplitude compared to female mice. The hair cell (HC) ribbon synapse (CtBP2) puncta showed significant sex differences. The serum concentration of adiponectin, an otoprotective adipokine, was significantly higher in female than in male mice; cochlear adiponectin levels were elevated by HFD in female but not male mice. Adiponectin receptor 1 (AdipoR1) was widely expressed in the inner ear, and cochlear AdipoR1 protein levels were increased by HFD, in female but not male mice. Stress granules (G3BP1) were significantly induced by the HFD in both sexes; conversely, inflammatory (IL-1ß) responses were observed only in the male liver and cochlea, consistent with phenotype HFD-induced obesity. CONCLUSIONS: Female mice are more resistant to the negative effects of an HFD on body weight, metabolism, and hearing. Females showed increased peripheral and intra-cochlear adiponectin and AdipoR1 levels, and HC ribbon synapses. These changes may mediate resistance to HFD-induced hearing loss seen in female mice.

Synthesis of Tantalum Carbide Using Purified Hexane by Titanium Powder.

Hexane is a safe, efficient, and cost-effective alternative to other commercial hydrocarbons for gaseous carburization; however, commercial hexane is not sufficiently pure. Titanium powder can remove oxygen-containing impurities from commercial hexane; however, research on the use of titanium powder remains limited. We investigated the purification of hexane using titanium, copper, and aluminum powders and used the purified hexane for the gaseous carburization of tantalum. Ti exhibited lower activation energy for oxidation (1.55 kJ/mol) than Cu (91.09 kJ/mol) and Al (150.25 kJ/mol) and a significantly higher oxidation rate (0.0269 g/h) in hexane at room temperature than Cu (0.0018 g/h) and Al (0.0001 g/h). The carbon content in tantalum carburized using the purified hexane was comparable to that carburized using unpurified hexane (approximately 6.22%); however, its oxygen content was significantly lower (1.39%), which indicates that the produced tantalum carbide has a higher purity. X-ray diffraction results revealed that the oxidation products of tantalum, such as Ta2O, TaO2, Ta0.8O2, and Ta2O5, were absent in the sample carburized using the purified hexane. Therefore, Ti powder can effectively remove oxygen-containing impurities from commercial hexane and facilitate its use as an effective carburizing medium for the synthesis of high-purity tantalum carbide.

Efficient Myogenic/Adipogenic Transdifferentiation of Bovine Fibroblasts in a 3D Bioprinting System for Steak-Type Cultured Meat Production.

The interest in cultured meat is increasing because of the problems with conventional livestock industry. Recently, many studies related to cultured meat have been conducted, but producing large-sized cultured meat remains a challenge. It is aimed to introduce 3D bioprinting for producing large cell aggregates for cultured meat production. A hydrogel scaffold is produced at the centimeter scale using a bioink consisting of photocrosslinkable materials for digital light processing-based (DLP) printing, which has high printing accuracy and can produce geometrically complex structures. The light exposure time for hydrogel photopolymerization by DLP bioprinting is optimized based on photorheometry and cell viability assays. Naturally immortalized bovine embryonic fibroblast cells transformed with MyoD and PPARγ2 instead of primary cells are used as the latter have difficulties in maintaining stemness and are associated with animal ethics issues. The cells are mixed into the hydrogel for printing. Myogenesis and adipogenesis are induced simply by changing the medium after printing. Scaffolds are obtained successfully with living cells and large microchannels. The cooked cultured meat maintains its size and shape upon cutting. The overall dimensions are 3.43 cm × 5.53 cm × 0.96 cm. This study provides proof-of-concept for producing 3D cultured meat using bioinks.

Dual modulators of aggregation and dissociation of amyloid beta and tau: In vitro, in vivo, and in silico studies of Uncaria rhynchophylla and its bioactive components.

A prominent characteristic of Alzheimer's disease (AD) is the deposition of both amyloid-ß (Aß) peptide and tau protein in the brain. Aß and tau not only induce toxicity through self-aggregation but also induce more potent toxicity through the synergistic action of Aß and tau. In particular, neurotoxic aggregates of Aß and tau directly affect several AD pathologies including neuroinflammation and cognitive decline. Therefore, there is increasing interest in strategies to modulate the aggregation and dissociation of Aß and tau for treatment of AD. Our recent study found that Uncaria rhynchophylla (UR) has a therapeutic effect on AD via the inhibition of Aß aggregation and attenuating Aß-mediated pathogenesis of AD. However, no studies have investigated whether UR has anti- and disaggregation effects on both Aß and tau. In this study, we showed the significant effects of UR on aggregation and dissociation of Aß42 and tau K18 using a thioflavin T (ThT) assay. In addition, histological study revealed an inhibitory effect of UR on the accumulation of Aß and tau and AD-related pathologies in 3xTg mice with both Aß and tau pathology. Furthermore, we found that rhynchophylline and corynoxeine, bioactive components of UR, could modulate the aggregation and dissociation of both Aß and tau using molecular docking simulation, isothermal titration calorimetry, and ThT assays. In conclusion, our results demonstrate that UR can inhibit the aggregation of Aß and tau and promote the degradation of their aggregates in AD.

Perception and expectations of personal sound amplification products in Korea: A hospital-based, multi-center, cross-sectional survey.

OBJECTIVES: The objective of this study was to investigate current perception and expected price of personal sound amplification products (PSAPs) and to analyze influencing factors through multi-center hospital-based surveys of outpatients, caregivers, and hearing experts. METHODS: A multi-center exploratory cross-sectional study was conducted in two groups of respondents with two separate surveys: 1) a perception survey of patients and caregivers who visited an otorhinolaryngology outpatient clinic in 5 general hospitals and 2) an opinion survey of hearing specialists about the expected price of PSAPs. A total of 197 outpatient visitors responded to the perception survey, and 42 hearing specialists responded to the opinion survey. RESULTS: Overall perception score (18 questions) was 3.04 (95% CI, 3.00-3.09). When 5 categories of perception (knowledge, needs, cost, expectation, and information categories) were analyzed, cost and expectation showed the highest scores of 3.33 (95% CI, 3.21-3.44) and 3.33 (95% CI, 3.27-3.40), respectively, and needs showed the lowest score of 2.23 (95% CI, 1.97-2.49). The ≥ 60-year-old group showed significantly higher perception of PSAPs (P = 0.002), and the individuals with greater severity of subjective hearing loss showed significantly higher perception of PSAPs (P = 0.002). The expected price of PSAPs of the outpatient visitors was 933.9 USD (95% CI, 811.9-1056.0) per ear. Mean expected price of PSAPs of hearing specialists was 291.3 USD (95% CI, 238.2-344.3) per ear. CONCLUSION: The perception rate of PSAPs was very low, and there was a discrepancy in the expected price of PSAPs between patients/caregivers and hearing experts. Hearing specialists should make effort to improve perception of PSAPs.

Knowledge and Expectations of Hearing Aid Apps Among Smartphone Users and Hearing Professionals: Cross-sectional Survey.

BACKGROUND: Despite the increasing prevalence of hearing loss, the cost and psychological barriers to the use of hearing aids may prevent their use in individuals with hearing loss. Patients with hearing loss can benefit from smartphone-based hearing aid apps (SHAAs), which are smartphone apps that use a mobile device as a sound amplifier. OBJECTIVE: The aim of this study is to determine how ear, nose, and throat outpatients perceive SHAAs, analyze the factors that affect their perceptions, and estimate the costs of an annual subscription to an app through a self-administered questionnaire survey of smartphone users and hearing specialists. METHODS: This study used a cross-sectional, multicenter survey of both ear, nose, and throat outpatients and hearing specialists. The questionnaire was designed to collect personal information about the respondents and their responses to 18 questions concerning SHAAs in five domains: knowledge, needs, cost, expectations, and information. Perception questions were rated on a scale of 1 (strongly disagree) to 5 (strongly agree). Questions about the expected cost of SHAAs were included in the questionnaire distributed to hearing experts. RESULTS: Among the 219 smartphone users and 42 hearing specialists, only 8 (3.7%) respondents recognized SHAAs, whereas 18% (47/261) of respondents reported considering the use of an assistive device to improve their hearing capacity. The average perception score was 2.81 (SD 1.22). Among the factors that shaped perceptions of SHAAs, the needs category received the lowest scores (2.02, SD 1.42), whereas the cost category received the highest scores (3.29, SD 1.14). Age was correlated with the information domain (P<.001), and an increased level of hearing impairment resulted in significantly higher points in the needs category (P<.001). Patients expected the cost of an annual app subscription to an SHAA to be approximately US $86, and the predicted cost was associated with economic status (P=.02) and was higher than the prices expected by hearing specialists (P<.001). CONCLUSIONS: Outpatients expected SHAAs to cost more than hearing specialists. However, the perception of the SHAA was relatively low. In this regard, enhanced awareness is required to popularize SHAAs.

Injectable glycol chitosan thermogel formulation for efficient inner ear drug delivery.

We prepared a new injectable thermogel to enhance the efficiency of inner ear delivery of dexamethasone (DEX). Hexanoyl glycol chitosan (HGC) was synthesized and evaluated as an amphiphilic thermogel (Tgel ~ 32 °C) for use as a solubilizing agent as well as an injectable carrier for intratympanic delivery of the hydrophilic and hydrophobic forms of DEX. Various thermogel formulations with different drug types and concentrations were prepared, and their physicochemical and thermogelling properties were characterized by 1H NMR, ATR-FTIR, and rheometer. They exhibited versatile release kinetics from several hours to more than 2 weeks, depending on drug type and concentration. Our formulations further showed good residual stability for more than 21 days without any cytotoxicity or inflammation in the middle and inner ear and could deliver a considerably high drug concentration into the inner ear. Therefore, HGC thermogel has great potential as an effective and safe formulation for inner ear drug delivery.