The Effect of Mesenchymal Stem Cells on Dry Eye in Sjogren Syndrome Mouse Model.

Sjögren's syndrome (SS) is a systemic autoimmune disease delineated by chronic lymphocytic infiltrates into the lacrimal or salivary glands, leading to severe dry eye and dry mouth. Mesenchymal stem cells have been shown to be effective in treating numerous autoimmune diseases. This study aimed to illustrate the effects of mesenchymal stem cells on the attenuation of dry eyes (DE) through the inhibition of autophagy markers in a SS mouse model. NOD/ShiLtJ female mice with developed DE were treated with either subconjunctival or lacrimal gland injections of hMSCs (Catholic MASTER Cells). After maintenance for 14 days, clinical DE markers such as tear secretion and corneal staining were observed, as well as goblet cell counts in the conjunctiva, infiltration of inflammatory foci, B and T cells, and autophagy markers in the lacrimal glands. Proinflammatory cytokine expressions of the cornea and conjunctiva, as well as the lacrimal glands, were examined. Clinical markers, such as tear secretion and corneal stain scores, goblet cell counts in the conjunctiva, and foci infiltrations in the lacrimal glands were attenuated in mice treated with subconjunctival or lacrimal gland injections of hMSCs compared to the PBS-treated control group. B cell marker B220 decreased in the lacrimal glands of hMSCs-treated mice, as well as reduced proinflammatory cytokine expressions in the lacrimal glands and cornea. Notably, expression of autophagy markers ATG5 and LC3B-II, as well as HIF-1α and mTOR which play roles in the pathways of autophagy modulation, were shown to be attenuated in the lacrimal glands of hMSCs-treated mice compared to the PBS-treated control mice. Treatment with hMSCs by lacrimal gland or subconjunctival injection demonstrated the alleviation of DE through the repression of autophagy markers, suggesting the therapeutic potentials of hMSCs in a SS mouse model.

Maxillary sinusitis developed as sequelae of accidental middle turbinectomy that occurred during nasotracheal intubation: a case report.

BACKGROUND: Nasotracheal intubation is a very useful technique for orofacial or dental surgery. However, the technique itself can be more traumatic than that of orotracheal intubation. Complications such as turbinectomy or bleeding are often reported. However, little is known about the follow-up of patients after these complications. CASE PRESENTATION: The present case describes an accidental middle turbinectomy that led to endotracheal tube obstruction during nasotracheal intubation, and discusses its long-term follow-up. A 19-year-old man underwent mandibular surgery under general anesthesia and nasotracheal intubation. His right middle turbinate was completely avulsed and became firmly occluded within the tube during nasotracheal intubation. The nasotracheal intubation was performed again and the operation was completed safely. The patient was discharged without sequelae after postoperative care. However, he had symptoms of nasal obstruction and sleep disturbance for 3 months postoperatively. Synechiae were detected between the nasal septum and lateral nasal wall on a right rhinoscopic examination and facial computed tomography at 3 months postoperatively. Additionally, he showed ipsilateral maxillary sinusitis on facial computed tomography at the 2-year follow-up examination. CONCLUSIONS: Nasotracheal intubation can cause late complications as well as early complications. Therefore, if nasotracheal intubation is to be performed, the anesthesiologist should identify the nasal anatomy of the patient accurately and prepare appropriately. In addition, if complications occur, follow-up observation should be performed.

ROS-Sensitive Degradable PEG-PCL-PEG Micellar Thermogel.

A reactive oxygen species (ROS)-sensitive degradable polymer would be a promising material in designing a disease-responsive system or accelerating degradation of polymers with slow hydrolysis kinetics. Here, a thermogelling poly(ethylene glycol)-polycaprolactone-poly(ethylene glycol) (PEG-PCL-PEG or EG12 -CL20 -EG12 ) triblock copolymer with an oxalate group at the middle of the polymer is reported. The polymers form micelles with an average size of 100 nm in water. Thermogelation is observed in a concentration range of 8.0-37.0 wt%. In particular, the aqueous PEG-PCL-PEG triblock copolymer solutions are in a gel state at 37 °C in a concentration range of 25.0-37.0 wt%, whereas the aqueous PEG-PCL diblock copolymer solutions are in a sol state in the same concentration range at 37 °C. Thus, the gel depot could dissolve out once degradation of the triblock copolymers occurs at the oxalate group as confirmed by the in vitro experiment. In vivo gel formation is confirmed by injecting an aqueous PEG-PCL-PEG solution (36.0 wt%) into the subcutaneous layer of rats. The gel completely disappears in 21 d. A model polypeptide drug (cyclosporine A) is released over 21 d from the in situ formed gel. The micelle-based thermogel of PEG-PCL-PEG with ROS-triggering degradability is a promising injectable material for biomedical applications.

Iron Ion-Releasing Polypeptide Thermogel for Neuronal Differentiation of Mesenchymal Stem Cells.

A poly(ethylene glycol)-based thermogel can capture an iron ion (Fe3+) through a crown ether-like coordination bond between the oxygen atom and metal ions, thus, providing a sustained Fe3+-releasing system. Poly(ethylene glycol)-l-poly(alanine) thermogel was used in this study. The polypeptide forms a rather robust gel, and the degradation products are a neutral amino acid, which provides cyto-compatible neutral pH environments during the cell culture. During the heat-induced sol-to-gel transition at 37 °C, tonsil-derived mesenchymal stem cells (TMSCs) and iron ions were incorporated, leading to the formation of a three-dimensional matrix toward neuronal differentiation of the incorporated TMSCs. The initial concentration of the iron ions was varied between 0, 15, 30, and 60 mM. About 10% of the loaded iron ions was released over 21 days, which continuously supplied iron ions to the cells. The incorporation of iron ions not only increased the gel modulus at 37 °C from 107 to 680 Pa, but also promoted cell aggregation with a significant secretion of the cell adhesion signal of FAK. Expression of biomarkers related to the neuronal differentiation of TMSCs, including NFM, MAP2, GFAP, NURR1, NSE, and TUBB3, increased 4-35-fold at the mRNA level in the Fe3+-containing system compared to that of the system without Fe3+. Immunofluorescence studies also confirmed pronounced cell aggregation and a significant increase in neuronal biomarkers at the protein level. This study suggests that an iron ion-releasing thermogelling system can be a promising injectable scaffold toward neuronal differentiation of stem cells.

Compound heterozygous mutations of SH3TC2 in Charcot-Marie-Tooth disease type 4C patients.

Charcot-Marie-Tooth disease type 4C (CMT4C) is an autosomal recessive neuropathy caused by SH3TC2 mutations, characterized by spine deformities and cranial nerve involvement. This study identified four CMT4C families with compound heterozygous SH3TC2 mutations from 504 Korean demyelinating or intermediate CMT patients. The frequency of the CMT4C was calculated as 0.79% in demyelinating and intermediate patients (n = 504), but it was calculated as 2.02% in patients without PMP22 duplication (n = 198). The CMT4C frequency was similar to patients in Japan, but it was relatively low compared to those patients in other populations. The symptom was less severe and slowly progressed compared to the other AR-CMT. A patient harboring an intermediate neuropathy showed cranial nerve involvement but did not have scoliosis. This study will be helpful in making molecular diagnoses of demyelinating or intermediate CMT due to SH3TC2 mutations.

Fast Degradable Polycaprolactone for Drug Delivery.

Polycaprolactone (PCL) was reported a long time ago; however, its biomedical applications has not been extensively investigated in comparison with poly(lactide- co-glycolide) (PLGA) due to its too slow degradation profile. Here, we are reporting an oxalate-connected oligocaprolactone multiblock copolymer (PCL-OX) as a fast degradable PCL while maintaining its crystalline properties and low melting point of PCL. The in vivo application of the paclitaxel-loaded PCL-OX microspheres provided a steady plasma drug concentration of 6-9 µg/mL over 28 days, similar to that of the PLGA microspheres. Both PCL and PLGA microspheres were completely cleared two months after in vivo implantation. The PCL-OX microspheres showed a similar tissue compatibility to that of PLGA microspheres in the subcutaneous layer of rats. These findings suggest that PCL-OX is a useful biomaterial that solves the slow degradation problems of PCL and, thus, may find uses in other biomedical applications as an alternative to PLGA.

α,ω-Diphenylalanine-End-Capping of PEG-PPG-PEG Polymers Changes the Micelle Morphology and Enhances Stability of the Thermogel.

Pluronics F127 (P, PEG-PPG-PEG triblock copolymer) was coupled with diphenylalanine (FF) to prepare FF-end-capped Pluronics (FFPFF). With increasing temperature from 10 to 60 °C, the FFPFF self-assembled to vesicles in water. The unimer-to-vesicle transition accompanies endothermic enthalpy of 53.9 kcal/mol. Aqueous P and FFPFF solutions exhibited thermogelation in 15.0-24.0 wt %. The gel phase of FFPFF was stable up to 90 °C, whereas that of P turned into a sol again at 55-86 °C, indicating that end-capping with FF improved the gel stability against heat. In addition, the carboxylic acids of the FF end-groups can form coordination bonds with metal ions, and the gel modulus at 37 °C increased from 15-21 KPa (P) to 20-25 KPa (FFPFF) to 24-28 KPa (FFPFF-Zn), and the duration of gel against water-erosion increased from 24 h (P) to 60 h (FFPFF-Zn), leading to a useful biomaterial for sustained drug delivery. The FFPFF-Zn gels implanted in the rats' subcutaneous layer induced a mild inflammatory responses. Contrary to the previous end-capping of Pluronics by poly(lactic acid), polycarprolactone, carboxylic acid, and so on that weakened the gel stability, the diphenylalanine end-capping strengthened the stability of Pluronics gel against heat and water-erosion. This paper suggests that the control of polymer nanoassemblies directed by FF end-groups improves the mechanical properties and stability of the resulting thermogel and, thus, provides a useful drug delivery carrier with prolonged durability.

Impact of varying food hardness on mastication/swallowing.

The purpose of this study was to analyze mastication and swallowing in the elderly and confirm the association with dysphagia characteristics. A questionnaire was developed to evaluate the masticating and swallowing functions of the elderly. Mastication was analyzed using electromyography, and tongue/lip pressures were measured using Iowa Oral Performance Instrument. The results of the questionnaire showed that statistical difference in the number of teeth between the group without and with, decreased ability to swallow, and there was a correlation with lip pressure. Additionally, the higher number of teeth, the higher muscle activity, and there is a positive correlation between the number of chews and the lip pressure. Consequently, our findings suggested oral health parameters are closely associated with mastication/swallowing ability. Finally, based on the results obtained for different foods tested, we suggested that texture-modified foods are necessary to enhance swallowing ability.

Polypropylene microplastics promote metastatic features in human breast cancer.

Microplastics (MPs) are now a global issue due to increased plastic production and use. Recently, various studies have been performed in response to the human health risk assessment. However, these studies have focused on spherical MPs, which have smooth edges and a spherical shape and account for less than 1% of MPs in nature. Unfortunately, studies on fragment-type MPs are very limited and remain in the initial stages. In this study, we studied the effect that 16.4 µm fragment type polypropylene (PP) MPs, which have an irregular shape and sharp edges and form naturally in the environment, had on breast cancer. The detrimental effects of PPMPs on breast cancer metastasis were examined. Here, 1.6 mg/ml of PPMP, which does not induce cytotoxicity in MDA-MB-231, was used, and at this concentration, PPMP did not induce morphological changes or cellular migrating in the MDA-MB-231 and MCF-7 cells. However, PPMP incubation for 24 hours in the MDA-MB-231 cells significantly altered the level of cell cycle-related transcripts in an RNA-seq analysis. When confirmed by qRT-PCR, the gene expression of TMBIM6, AP2M1, and PTP4A2 was increased, while the transcript level of FTH1 was decreased. Further, secretion of the pro-inflammatory cytokine IL-6 from cancer cells was elevated with the incubation of PPMP for 12 hours. These results suggest that PPMP enhances metastasis-related gene expression and cytokines in breast cancer cells, exacerbating breast cancer metastasis.

dl-Polyalanine as a PEG-Free Thermogel.

Thermogelling behavior of aqueous polymer solutions comes from the delicate balance between hydrophilic and hydrophobic moieties of the polymer. Typically, poly(ethylene glycol) (PEG) has been used as a hydrophilic block in most thermogels reported to date. However, recent papers have suggested the potential immunogenicity of PEG-conjugated compounds. Here, we report that aqueous solutions of dl-polyalanine (DL-PA) with a specific molecular weight can exhibit thermogelling behavior. In particular, DL-PA with a molecular weight (Mn) of 6690 Da, DL-PA67, exhibited sol-to-gel transition at the physiologically important temperature range of 30-40 °C. 1H NMR and FTIR data indicated that the mechanism of thermogelation is related to dehydration and conformational changes of DL-PA67 from random coil to ß-sheet structures. Subcutaneous injection of an aqueous DL-PA67 solution into rats confirmed the gel formation and its histocompatibility with mild tissue irritation.

Hyaluronic acid-g-PPG and PEG-PPG-PEG hybrid thermogel for prolonged gel stability and sustained drug release.

Hyaluronic acid-graft-poly(propylene glycol) (HA-g-PPG) was prepared to induce hydrophobic interactions between HA-g-PPG and F127 PPGs (poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol)) and consequent increases in gel stability of F127 gel. Molecular weights of 340, 1000, and 2500 Da were used for PPG, and grafting ratios of HA-g-PPG varied over 3%, 12%, and 50%. Using rheology measurements, 1H NMR spectra, lower critical solution temperature measurements, dynamic light scattering, and transmission electron spectroscopy, hydrophobic crosslinking and intermicellar bridge formation were suggested in the aqueous HA-g-PPG/F127 hybrid solutions. In particular, the gel stability of the HA-g-PPG/F127 hybrid thermogel increased from 2 days (F127 only) to 6 days, thus the hybrid thermogel can provide longer delivery of an incorporated drug. The HA-g-PPG/F127 thermogel exhibited tissue compatibility in the subcutaneous layer of rats. The protein drug release from the gel indicated that interactions between negative charged HA-g-PPG and positive charged drug (calcitonin) reduced initial burst release.

Poly(l-Ala-co-l-Lys) Exhibits Excellent Ice Recrystallization Inhibition Activity.

The control of ice recrystallization is very important in cryo-technological fields such as the food industry, biopharmaceuticals, and cell storage. Ice recrystallization inhibition (IRI) compounds are therefore designed to limit the growth of ice crystals, decrease the crystal size, and control the crystal shape. To improve the IRI activity of cryo-systems, various synthetic polymers such as biomimetic polypeptides from polar fish, facially amphiphilic polymers, polyampholytes, poly(vinyl alcohol) derivatives, and block copolymers with hydrophilic-hydrophobic balance have been developed. Except for graphene oxide, poly(vinyl alcohol) has thus far exhibited the best performance among these polymers. Herein, poly(l-alanine-co-l-lysine) (PAK) was shown to exhibit a similar IRI activity to that of poly(vinyl alcohol). Moreover, in contrast to the needle-shaped ice crystals generated by the aqueous PVA solution, the PAK solution was shown to generate cubic-to-spherical shaped ice crystals. Furthermore, neither poly(l-alanine-co-l-aspartic acid) (PAD) nor poly(ethylene glycol) (PEG) with a similar molecular weight provided any significant IRI activity. Examination by FTIR and circular dichroism spectroscopies indicated that the PAK forms α-helices, whereas the PAD forms random coils in water. Further, a dynamic ice shaping study suggested that PAK strongly interacts with ice crystals, whereas PAD and PEG only weakly interact. These results suggest that PAK is an important compound with superior IRI activity and that this activity is dependent upon the functional groups and secondary structure of the polypeptides.

Frequency of putative enteric zoster diagnosed using saliva samples in patients with abdominal pain: a prospective study.

BACKGROUND: Varicella-zoster virus (VZV) infects and establishes latency in neurons in the ganglia of the cranial nerve, dorsal root and enteric ganglia. VZV reactivation in enteric neurons (enteric zoster) can cause non-specific abdominal pain and/or serious gastrointestinal dysfunction without cutaneous manifestations. Detection of VZV DNA in saliva may be useful for identifying enteric zoster. We evaluated the frequency of putative enteric zoster based on the presence of salivary VZV DNA in patients with acute abdominal pain. METHODS: Adult patients who visited the emergency room due to moderate to severe acute abdominal pain were prospectively enrolled at a tertiary hospital between May 2019 and November 2019. Abdominopelvic computed tomography (APCT) was performed in all patients. We also evaluated the presence of salivary VZV DNA in patients with confirmed coronavirus disease-19 (COVID-19) who were under stressful conditions. Saliva samples were collected from all studied patients. Enteric zoster was suspected based on the presence of salivary VZV DNA, detected using real-time polymerase chain reaction (PCR). RESULTS: Fifty patients with moderate to severe abdominal pain were enrolled. Five of 50 patients exhibited positive VZV-DNA PCR results. APCT revealed that among these five patients, two had pancreatic head cancer, two had small bowel obstruction after intra-abdominal surgery, and one had no remarkable findings. However, all 14 patients with COVID-19 showed negative salivary VZV-DNA PCR results. CONCLUSIONS: Approximately 10% of patients with moderate to severe acute abdominal pain showed positivity for salivary VZV DNA. Further studies are warranted on whether antiviral therapy based on salivary VZV-DNA PCR results may relieve abdominal pain in the studied patient population. TRIAL REGISTRATION: clinicaltrial.gov, number NCT03862092.

Dynamics of Viral Shedding and Symptoms in Patients with Asymptomatic or Mild COVID-19.

We conducted a prospective cohort study at a community facility designated for the isolation of individuals with asymptomatic or mild COVID-19 between 10 January and 22 February 2021 to investigate the relationship of viral shedding with symptom changes of COVID-19. In total, 89 COVID-19 adult patients (12 asymptomatic, 16 presymptomatic, 61 symptomatic) were enrolled. Symptom scores, the genomic RNA and subgenomic RNA of SARS-CoV-2 from saliva samples with a cell culture were measured. Asymptomatic COVID-19 patients had a similar viral load to symptomatic patients during the early course of the disease, but exhibited a rapid decrease in viral load with the loss of infectivity. Subgenomic RNA and viable virus by cell culture in asymptomatic patients were detected only until 3 days after diagnosis, and the positivity of the subgenomic RNA and cell culture in symptomatic patients gradually decreased in both from 40% in the early disease course to 13% at 10 days and 4% at 8 days after the symptom onset, respectively. In conclusion, symptomatic patients have a high infectivity with high symptom scores during the early disease course and gradually lose infectivity depending on the symptom. Conversely, asymptomatic patients exhibit a rapid decrease in viral load with the loss of infectivity, despite a similar viral load during the early disease course.

Both Intracranial and Intravenous Administration of Functionalized Carbon Nanotubes Protect Dopaminergic Neuronal Death from 6-Hydroxydopamine.

PURPOSE: Although single-walled nanotubes (SWNTs) with functional groups have been suggested as a potential nanomedicine to treat neuronal disorders, effective routes to administer SWNTs have not been compared thus far. The blood-brain barrier is a considerable challenge for the development of brain-targeting drugs, and therefore functionalized SWNT routes of administration have been needed for testing Parkinson's disease (PD) treatment. Here, effective administration routes of functionalized SWNTs were evaluated in PD mouse model. METHODS: Three different administration routes were tested in PD mouse model. Functionalized SWNTs were injected directly into the lateral ventricle three days before (Method 1) or after (Method 2) 6-hydroxydopamine (6-OHDA) injection to compare the protective effects of SWNTs against dopaminergic neuronal death or functionalized SWNTs were injected intravenously at three and four days after 6-OHDA injection (Method 3). Asymmetric behaviors and histological assessment from all animals were performed at two weeks after 6-OHDA injection. RESULTS: Ventricular injections of SWNTs both before or after 6-OHDA exposure protected dopaminergic neurons both in the substantia nigra and striatum and alleviated rotational asymmetry behavior in PD mice. Moreover, intravenous administration of SWNTs three and four days after 6-OHDA injection also prevented neuronal death and PD mice behavioral impairment without apparent cytotoxicity after six months post-treatment. CONCLUSION: Our study demonstrates that functionalized SWNTs could effectively protect dopaminergic neurons through all administration routes examined herein. Therefore, SWNTs are promising nanomedicine agents by themselves or as therapeutic carriers to treat neuronal disorders such as PD.

Periodontitis combined with smoking increases risk of the ulcerative colitis: A national cohort study.

BACKGROUND: Periodontitis is a chronic inflammation of periodontal tissues. The effect of periodontitis on the development of inflammatory bowel disease (IBD) remains unclear. AIM: To assessed the risk of IBD among patients with periodontitis, and the risk factors for IBD related to periodontitis. METHODS: A nationwide population-based cohort study was performed using claims data from the Korean National Healthcare Insurance Service. In total, 9950548 individuals aged ≥ 20 years who underwent national health screening in 2009 were included. Newly diagnosed IBD [Crohn's disease (CD), ulcerative colitis (UC)] using the International Classification of Disease 10th revision and rare intractable disease codes, was compared between the periodontitis and non-periodontitis groups until 2017. RESULTS: A total of 1092825 individuals (11.0%) had periodontitis. Periodontitis was significantly associated with older age, male gender, higher body mass index, quitting smoking, not drinking alcohol, and regular exercise. The mean age was 51.4 ± 12.9 years in the periodontitis group and 46.6 ± 14.2 years in the non-periodontitis group (P < 0.01), respectively. The mean body mass index was 23.9 ± 3.1 and 23.7 ± 3.2 in the periodontitis and non-periodontitis groups, respectively (P < 0.01). Men were 604307 (55.3%) and 4844383 (54.7%) in the periodontitis and non-periodontitis groups, respectively. The mean follow-up duration was 7.26 years. Individuals with periodontitis had a significantly higher risk of UC than those without periodontitis [adjusted hazard ratio: 1.091; 95% confidence interval (CI): 1.008-1.182], but not CD (adjusted hazard ratio: 0.879; 95% confidence interval: 0.731-1.057). The risks for UC were significant in the subgroups of age ≥ 65 years, male gender, alcohol drinker, current smoker, and reduced physical activity. Current smokers aged ≥ 65 years with periodontitis were at a 1.9-fold increased risk of UC than non-smokers aged ≥ 65 years without periodontitis. CONCLUSION: Periodontitis was significantly associated with the risk of developing UC, but not CD, particularly in current smokers aged ≥ 65 years.

Incorporation of chitosan-alginate complex into injectable calcium phosphate cement system as a bone graft material.

Calcium phosphate brushite type of cements have been used to replace bone graft materials because of their biocompatibility and other attractive features. Especially, injectability of cement allows easy handling of minimally invasive surgical techniques. New calcium phosphate cement (CPC) system, brushite based cement incorporated into polyelectrolyte complex, was developed in this study. Chitosan-alginate complex produced by an interaction between a cationic polymer (chitosan) and an anionic polymer (alginate) was loaded in the cement. This improved the functional properties and biocompatibility of the final cement. We optimized the liquid/solid (L/S) ratio of the cement components and investigated the compressive strength, setting time, pH change of CPC0 (with only citric acid) and CPC0.5, 1, and 1.5 (0.5, 1, and 1.5 v/v % chitosan-alginate complex in citric acid solution, respectively). The L/S ratio did not affect structural formation, while the addition of polymer complex showed new formation of macro-pores within CPC. However, a lower L/S ratio and higher amount of added polymer complex shortened the setting time and improved the compressive strength. The appropriate conditions for the injectable bone substitute were CPC1 with an L/S ratio of 0.45. To investigate the effect of the chitosan-alginate complex on CPC system in physiological conditions, CPC0 and CPC1 were implanted in a rabbit femoral head defect model for 1 and 3 months. Micro-computed tomography revealed improved bone formation in CPC1 compared to CPC0 3 months after implantation. Histological analysis revealed newly formed bone tissues around the peripheral sides of CPC0 and CPC1. The results indicate the potential value of the CPC system containing polymer complex as an injectable bone substitute. The study of the CPC-polymer complex system incorporating drugs or cells can be further developed into a controlled release system for faster bone regeneration.

Fabrication and characterization of 3D-printed elastic auricular scaffolds: A pilot study.

OBJECTIVE: Aesthetic reconstruction of the external ear is challenging due to the complex anatomical shape of the auricle. Recently, artificial scaffolds such as Medpor (Stryker, Kalamasoo, MI, USA) have become widely used in ear reconstruction. However, the Medpor scaffold is stiffer than the natural ear, which may lead to discomfort, and moreover has uniform design for every patient. In this study, we investigated whether three-dimensional (3D)-printed artificial polyurethane (PU) scaffolds are suitable for auricular reconstruction. METHODS: PU scaffolds were fabricated using 3D printing according to a design derived from a digital imaging and communications in medicine (DICOM) image of the human auricle. The microstructure of the scaffolds was observed using scanning electron microscopy, and the porosity was examined. Cell proliferation on the scaffolds was assessed in vitro using tonsil-derived mesenchymal stem cells to evaluate the biocompatibility of the scaffolds. The scaffolds were implanted in C57BL/6 mice, and histological analysis was performed. RESULTS: The structural study revealed that the 3D-printed porous PU scaffolds have rectangular microstructure with regular pitch and line, as well as high porosity (56.46% ± 10.22%) with a pore diameter of 200 µm. The mechanical properties of the 3D-printed PU scaffolds were similar to those of the human auricle cartilage. Cell proliferation on the PU scaffolds was greater than that on Medpor scaffolds. Histological evaluation demonstrated that the porous parts of the PU scaffolds became filled with collagen and vascular tissue. CONCLUSION: Elastic, porous PU scaffolds can be obtained using 3D printing, have biomechanical properties similar to those of the natural ear, and are suitable for use in auricular reconstruction. LEVEL OF EVIDENCE: NA Laryngoscope, 129:351-357, 2019.

Identification of cell-penetrating osteogenic peptide from copine-7 protein and its delivery system for enhanced bone formation.

Peptide and proteins are recognized as highly selective and therapeutically active biomaterials, as well as relatively safe in clinical application. A calcium phospholipid-binding protein, copine 7 (CPNE7), has been recently identified to induce hard tissue regeneration, including bone and dentin by internalizing into the cells. However, the clinical application of the full length of CPNE7 has limited due to its large size with short half-life. Herein, as an alternative to CPNE7, six bioactive synthetic peptides are designed from CPNE7 (CPNE7-derived peptides, CDP1-CDP6) and investigated their osteogenic potential. Among the CDPs, CDP4 have the highest level of cell-penetrating activity as well as osteogenic efficiency in dental pulp stem cells (DPSCs). CDP4 increased the expression of osteogenesis-related genes and proteins, which was comparable to that by BMP-2. The cell penetration capacity of CDP4 may synergistically induce the osteogenic potential of DPSCs. Moreover, the implantation of the mixture of CDP4 with injectable collagen gel increased bone formation with recovery in the mouse calvarial defect model, comparable to full-length CPNE7 and even BMP-2. In conclusion, these results suggest that our synthetic peptide, CDP4, can be applied in combination with biomaterial to provide high osteogenic efficacy in the field of bone tissue engineering.

Injectable thermogel for 3D culture of stem cells.

Thermogel is an aqueous polymer solution that undergoes sol-to-gel transition as the temperature increases. Cells, growth factors, and signaling molecules can be incorporated simultaneously during the sol-to-gel transition. The cytocompatible procedure makes the thermogel an excellent platform for 3D culture of stem cells. This review focuses on the crucial questions that need to be addressed to achieve effective differentiation of stem cells into target cells, comprising low modulus, cell adhesion, and controlled supply of the growth factors. Recent progress in the use of thermogel as a 3D culture system of stem cells is summarized, and our perspectives on designing a new thermogel for 3D culture and its eventual application to injectable tissue engineering of stem cells are presented.