Chronic intermittent hypoxia impacts the olfactory nervous system in an age-dependent manner: pilot study.

PURPOSE: Obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse during sleep, which induces chronic intermittent hypoxia (CIH). CIH results in low-grade inflammation, sympathetic overactivity, and oxidative stress. Nevertheless, it remains unclear how exposure to CIH affects olfaction. The purpose of this study was, therefore, to investigate the cytotoxic effects of CIH exposure on mouse olfactory epithelium and the underlying pathophysiology involved. METHODS: Mice were randomly divided into four groups: Youth mouse (You) + room air (RA), You + intermittent hypoxia (IH), Elderly mouse (Eld) + RA, and Eld + IH (n = 6 mice/group). Mice in the two hypoxia groups were exposed to CIH. The control condition involved exposure to room air (RA) for 4 weeks. Olfactory neuroepithelium was harvested for histologic examination, gene ontology analysis, quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting. RESULTS: Based on qRT-PCR analysis, olfactory marker protein (OMP), Olfr1507, ADCY3, and GNAL mRNA levels were lower, whereas NGFR, CNPase, NGFRAP1, NeuN, and MAP-2 mRNA levels were higher in the You + IH group than in the You + RA group. Olfactory receptor-regulated genes, neurogenesis-related genes and immunohistochemical results were altered in nasal neuroepithelium under CIH exposure. CONCLUSIONS: Based on genetic and cytologic analysis, CIH impacted the olfactory neuroepithelium in an age-dependent manner. Our findings suggest that CIH-induced damage to the olfactory neuroepithelium may induce more severe change in the youth than in the elderly.

3D-structural change of nasopharynx following adenoidectomy: 10-year serial data in a single hospital.

PURPOSE: Scar contracture commonly refers to decreased function in the scar area, whereas scar contraction refers to shortening of the scar length compared to the original wound. Wound scar remodeling occurs during months to years of wound healing to form a mature scar. Serial reports about patients who had undergone adenoidectomy are rare. Thus, the objective of this study was to evaluate some parameters of air way passage in patients who had undergone post adenoidectomy. METHODS: Data of patients who have undergone adenoidectomy between 2000 and 2002 in our hospital were obtained. A total of 154 head and neck CT scans from an adenoidectomy group and a control group were analyzed. We measured lengths of several areas, including the width of posterior wall of nasopharynx, the widest diameter in the upper air way, the length between both Eustachian tubes, the length between both pharyngeal recesses, and the anterior to posterior diameter of the nasopharynx. This study was approved by Institutional Review Board (IRB) of the Department of Otolaryngology Head and Neck Surgery of Catholic University (approval number: UC18RESI0130). RESULTS: There were significant differences in the following parameters between the two groups: the width of posterior wall of nasopharynx and the length between both pharyngeal recesses. CONCLUSION: Extensive removal of soft tissue or injured muscle layer during surgery might be one of the reasons for the narrowing of airway. Keeping in mind not to make much injury the soft tissue or muscles during adenoidectomy is very important for the long-term outcome of this surgery.

In vivo Oxygen Condition of Human Nasal Inferior Turbinate-Derived Stem Cells in Human Nose.

BACKGROUND AND OBJECTIVE: Human nasal inferior turbinate-derived stem cells (hNTSCs) have been considered as a potent and useful source for regenerative medicine. To most effectively mimic the native environment of inferior turbinate could be very effective to hNTSCs biology. Thus, the purpose of this study was to evaluate partial pressure of oxygen (ppO2) and temperature in inferior turbinate. METHODS: Ten patients were enrolled who underwent endoscopic endonasal transsphenoidal skull base tumor surgery between January 2014 and December 2015. The commercially available OxyLab pO2 monitor gauges the ppO2 and temperature using a fluorescence quenching technique. Also, hNTSCs were isolated from 10 patients and cultivated under hypercapnic condition (5, 10, and 15%) to mimic hypoxic intranasal conditions. RESULTS: The measured oxygen concentration in submucosa tissue was higher than that at the surface of the inferior turbinate and the temperature in submucosa tissue was higher than the value at the surface of inferior turbinate. The patterns of proliferation were significantly different according to hypercapnic cultivation conditions and there were statistically significant decreased proliferation rates after the exposure of higher CO2 over a period of 5 days. CONCLUSIONS: Intranasal turbinate tissue showed the hypoxia state in concordance with the result of the other tissues or organs. However, indirectly induced hypoxia influenced the influence on the hNTSCs proliferation negatively. Further study is needed to mimic the real hypoxic state, but our results could be used to optimize the culture environment of hNTSCs, thereby producing the stem cells for regenerative therapies.

Modification of Septal Window to Improve Angled Endoscopic View for Beyond Maxillary Sinus.

Many endoscopic surgeons have showed various techniques on septal window using endoscopic tools. However, each technique has its own merits and faults. In this study, the authors introduce simple and time saving endoscopic window technique by avoiding intranasal suture resulting from simple incision line. The procedure to make septal window is to improve an angled endoscopic view for beyond lateral wall of maxillary sinus with septum preservation. To date, this approach has shown no major or concerning complications and has also showed favorable disease control outcomes while maintaining nasal airway patency and functionality through our experience.

Characteristics of Atypical Orbital Complications of Sinusitis.

INTRODUCTION: Orbital complications of rhinosinusitis in adults are scarcely discussed in the literature. We defined atypical orbital complications as those without typical orbital invasion and not classified by the Chandler classification. These complications present as visual loss of diplopia without soft tissue swelling, pain, or computed tomography images of an orbital abscess. OBJECTIVES: The objective of this study was to review our experience with the management of atypical orbital complications of rhinosinusitis and to identify key factors in the characteristics of these patients. METHODS: A retrospective case series review was conducted from 2015 to 2019 in a tertiary referral center, which included all patients with rhinosinusitis and orbital complications. RESULTS: Five patients were identified with atypical complications in the orbital area. Two of the 5 patients exhibited vision loss without any other symptoms. Two patients showed diplopia with or without ptosis. One patient had a headache and ptosis. Complete recovery was noted in 4 of the 5 patients after endoscopic sinus surgery. CONCLUSION: With future studies, new surgical criteria, including retinal destruction, location of the sinusitis, the onset of ophthalmological symptoms, and culture results may be added to the classical surgical criteria to manage orbital complications of paranasal sinus infection cases.

Structural and functional analysis of a dimeric fumarylacetoacetate hydrolase (EaFAH) from psychrophilic Exiguobacterium antarcticum.

Fumarylacetoacetate hydrolase (FAH) is essential for the degradation of aromatic amino acids as well as for the cleavage of carbon-carbon bonds in metabolites or small organic compounds. Here, the X-ray crystal structure of EaFAH, a dimeric fumarylacetoacetate hydrolase from Exiguobacterium antarcticum, was determined, and its functional properties were investigated using biochemical methods. EaFAH adopts a mixed ß-sandwich roll fold with a highly flexible lid region (Val73-Leu94), and an Mg2+ ion is bound at the active site by coordinating to the three carboxylate oxygen atoms of Glu124, Glu126, and Asp155. The hydrolytic activity of EaFAH toward various substrates, including linalyl acetate was investigated using native polyacrylamide gel electrophoresis, activity staining, gel filtration, circular dichroism spectroscopy, fluorescence, and enzyme assays.

Characterization and mutation anaylsis of a cold-active bacterial hormone-sensitive lipase from Salinisphaera sp. P7-4.

In mammals, hormone sensitive lipase (EC 3.1.1.79, HSL) catalyzes the hydrolysis of triacylglycerols as well as the modifications of a broad range of hydrophobic substrates containing ester linkages. HSLs are composed of an N-terminal ligand-binding domain and a C-terminal catalytic domain. Bacterial hormone-sensitive lipases (bHSLs), which are homologous to the C-terminal domain of mammalian HSLs, have a catalytic triad composed of Ser, His, and Asp. Here, a novel cold-active hormone-sensitive lipase (SaHSL) from Salinisphaera sp. P7-4 was identified, functionally characterized, and subjected to site-directed mutations. The enzymatic properties of SaHSL were investigated using several biochemical and biophysical methods. Interestingly, SaHSL exhibited the ability to act on a broad range of substrates including glyceryl tributyrate and glucose pentaacetate. Homology modeling and site-directed mutagenesis indicated that hydrophobic residues (Leu156, Phe164, and Val204) around the substrate-binding pocket were involved in substrate recognition. In addition, highly conserved amino acids (Glu201, Arg207, Leu208, and Asp227) in the regulatory regions were found to be responsible for substrate specificity, thermostability, and enantioselectivity. In summary, this work provides new insights into the understanding of the C-terminal domain of HSL family and evidence that SaHSL can be used in a wide range of industrial applications.

Intranasal azelastine and mometasone exhibit a synergistic effect on a murine model of allergic rhinitis.

PURPOSE: The purpose of this study was to compare the anti-allergic effects of the combination of azelastine and mometasone with those of either agent alone in a Dermatophagoides farinae (Derf)-induced murine model of allergic rhinitis (AR). MATERIALS AND METHODS: Forty BALB/c mice were divided into five groups: azelastine (A), mometasone (M), a combination of azelastine and mometasone (MA), Derf, and control. Derf served as the allergen. Allergic symptom scores, eosinophil counts, and serum Derf-specific IgE levels were measured. The mucosal levels of mRNAs encoding interferon (IFN)-γ, T-bet, interleukin (IL)-4, GATA-3, Foxp3, IL-17, and ROR-γt were determined by real-time polymerase chain reaction. The T-bet, GATA-3, Foxp3, and ROR-γt results were confirmed by Western blotting. RESULTS: Nose-rubbing motions; the levels of mRNAs encoding IL-4, GATA-3, and ROR-γt; and tissue eosinophil count were reduced in the MA compared with those in the Derf group (all P values <0.05). The levels of mRNAs encoding GATA3 and IL-4 mRNA [synthesized by T helper (Th)2 cells] were reduced and that of mRNA encoding Foxp3 was increased in the MA compared with those in the Derf and A groups. Western blotting confirmed these findings. CONCLUSION: We found that the combination of intranasal azelastine and mometasone synergistically suppressed Th17 responses and (reciprocally) elevated Treg responses. Therefore, this combination not only ameliorated allergic inflammation by suppressing Th2 responses, but also usefully modified the Treg/Th17 balance.

Transnasal Endoscopic Resection of a Pleomorphic Adenoma Originate From Nasal Floor.

A 81-year-old female presented to our hospital frequent epistaxis. Nasal endoscopy showed a mass obstructing nasal cavity completely and occupying middle meatus. Magnetic resonance imaging was performed, an about 4.8 × 4 × 4.2 cm sized heterogeneous T2 high signal intensity and T1 enhancing mass mainly involving right nasal cavity with invasion of right hard palate with bony destruction. Therefore, the authors planned to do endoscopic mass excision, under general anesthesia for diagnosis and treatment. The authors removed the mass from lateral nasal wall, nasal roof, nasal septum, medial maxillary wall by piece-meal. Margins of mass were clear except the nasal floor. So, the authors did frozen biopsy to confirm the clear margin in nasal floor. Endoscopy enables better visualization of tumor margins, facilitating complete removal and avoiding excessive resection and following up using good visualization.

How to Expose the Entire Sella Floor With Minimal Manipulation During an Endoscopic Endonasal Transsphenoidal Approach.

OBJECTIVE: A method of opening the posterior ethmoid air cells with minimal manipulation is important for adequate exposure of the sella floor and minimal nasal morbidity. METHODS: Between February 2009 and August 2016, 373 patients with skull-base tumors underwent surgery via endoscopic endonasal transsphenoidal approach with the 2-nostrils/4-hands technique using this technique. RESULTS: A linear incision was made laterally toward one-third of the superior turbinate along the superior border of the sphenoid sinus ostium. Then, the superior turbinate mucosa was fully elevated to expose the superior turbinate bone. This allowed us to expose the entire sella floor and adjacent vital structures, such as the optic and carotid protuberances, medial and lateral opticocarotid recesses, planum sphenoidale, and clivus, leaving the superior turbinate and surrounding nasal mucosa intact. CONCLUSION: This technique could improve the manipulability of surgical instruments and increase the accessibility of the parasellar region. This approach better conserves the nasal mucosa, posterior ethmoid, and superior and supreme turbinates and more efficiently exposes skull-base tumors than traditional methods with pathology of the anterior cranial fossa and parasellar region. This technique also prevents the drilling procedure from damaging the surrounding nasal mucosa, including the exfoliated and laterally preserved posterior sphenoid mucosa.

Risk Factors Predicting Nasoseptal Flap Failure in the Endoscopic Endonasal Transsphenoidal Approach.

OBJECTIVE: Reconstruction of the skull base using a pedicled nasoseptal flap (NSF) seems to be advantageous after the endoscopic endonasal transsphenoidal approach (EETSA). A few reports have evaluated the cause of flap failure in EETSA using NSFs. The aim of this study was to evaluate the perioperative risk factors for NSF failure. STUDY DESIGN: Patient series. SETTING: Retrospective review of medical records at a tertiary referral center. METHODS: The study population comprised patients who underwent EETSA with NSF elevation between February 2009 and March 2014. The authors retrospectively reviewed the all patients' medical records, including operative findings. RESULTS: Four hundred thirteen patients (203 males and 210 females) underwent EETSA, and 315 patients underwent EETSA with NSF elevation. The mean patient age was 48.0 years. The total number of patients of NSF failure was 6 (overall rate: 1.61%, 6/315; flap elevation: 0.31%, 1/315; flap reconstruction: 15.1%, 5/33). Two patients had diabetes mellitus. One patient had cardiovascular problems. Five patients were elderly (>60 years; mean age: 70 years). Five patients had postoperative nasal infection. One patient underwent preoperative radiation therapy. CONCLUSION: Nasoseptal flap is a usually safe and effective technique for skull base reconstruction. However, the management of patients with diabetes mellitus, cardiovascular problems, advanced age, postoperative nasal infection, and radiation therapy may require more attention to improve NSF survival.

Bacillus cereus and Bacillus thuringiensis spores in Korean rice: prevalence and toxin production as affected by production area and degree of milling.

We determined the prevalence of and toxin production by Bacillus cereus and Bacillus thuringiensis in Korean rice as affected by production area and degree of milling. Rough rice was collected from 64 farms in 22 agricultural areas and polished to produce brown and white rice. In total, rice samples were broadly contaminated with B. cereus spores, with no effect of production area. The prevalence and counts of B. cereus spores declined as milling progressed. Frequencies of hemolysin BL (HBL) production by isolates were significantly (P ≤ 0.01) reduced as milling progressed. This pattern corresponded with the presence of genes encoding the diarrheal enterotoxins. The frequency of B. cereus isolates positive for hblC, hblD, or nheB genes decreased as milling progressed. Because most B. cereus isolates from rice samples contained six enterotoxin genes, we concluded that B. cereus in rice produced in Korea is predominantly of the diarrheagenic type. The prevalence of B. thuringiensis in rice was significantly lower than that of B. cereus and not correlated with production area. All B. thuringiensis isolates were of the diarrheagenic type. This study provides information useful for predicting safety risks associated with B. cereus and B. thuringiensis in rough and processed Korean rice.

Postoperative nasal symptoms associated with an endoscopic endonasal transsphenoidal approach.

Recent studies have indicated the usefulness of endoscopic endonasal transsphenoidal approach (EETSA). A few studies have reported on the postoperative nasal symptoms of patients who have undergone EETSA. Therefore, we adopted a rhinologic perspective to compare preoperative and postoperative nasal symptoms after performing a binostril, four-hand EETSA. Patients who were scheduled to undergo binostril, four-hand EETSA underwent preoperative nasal evaluation using the Nasal Obstruction Symptom Evaluation (NOSE), Sino-Nasal Outcome Test-20 (SNOT-20), and a visual analogue scale (VAS) to assess several nasal symptoms. Repeat testing was performed 6 months postoperatively. Paired Student's t tests were used to compare preoperative and postoperative scores. A total of 142 patients who underwent a binostril, four-hand EETSA were included in this study. We found no statistically significant differences between preoperative and postoperative NOSE, total SNOT-20 scores, or scores on the VAS for nasal obstruction, sneezing, rhinorrhea, snoring, or facial pain. However, VAS of olfactory change increased significantly after EETSA (p < 0.05). The binostril, four-hand EETSA would be a useful method because it permits operative manipulability and a wide visual field for skull base lesions. However, rhinologists must consider postoperative nasal symptoms and perform a proper preoperative examination, especially with regard to the olfactory function, and inform patients scheduled for EETSA of potential postoperative changes.

Endoscope-Assisted Multilayered Repair in Oronasal Fistula.

Oronasal fistula following cleft palate repair is a considerable complication with a recurrence rate of 33% to 37% and remains a challenging problem for surgeons. Furthermore, many patients have undergone several operations and experienced scar problems and other forms of morbidity. Therefore, we report a multilayered technique for oronasal fistula closure using an endoscopic nasal inferior turbinate composite graft with a palatal advance flap. This will increase the success rate after closure of small-sized oronasal fistula surgery without complications or recurrence (IRB: 2020-1671-0001).

The Effects of the Levels of Hypoxia in the Olfactory Nervous System in Mouse Model.

PURPOSE: Intermittent hypoxia (IH) results in low-grade inflammation, sympathetic overactivity, and oxidative stress. However, the specific effects of IH on olfaction have not yet been directly assessed and remain unclear. Therefore, the purpose of this study was to investigate the cytotoxic effects of IH exposure on the mouse olfactory epithelium and the relationship between the concentration of hypoxia and the degree of destruction of the olfactory system. METHODS: Thirty mice were randomly divided into six groups: control (room air for 4 weeks), recovery control (room air for 5 weeks), IH 5% oxygen concentration, IH 7% oxygen concentration, recovery 5% hypoxia, and recovery 7% hypoxia groups. Mice in the two hypoxia groups were exposed to 5% and 7% oxygen for 4 weeks. Mice in the two recovery groups were exposed to room air for 1 week after 4 weeks of hypoxia period. RESULTS: Based on, the olfactory marker protein (OMP), Olfr1507, ADCY3, and GNAL were lower, whereas S100b and NGFRAP1 messenger RNA (mRNA) levels were higher in the 5% hypoxia group than those in the control group in the olfactory neuroepithelium. In the brain tissue, the changes in RNA analysis for Olfr 1507, OMP, ADCY, and GNAL mRNA were not typical. However, NeuN and GFAP levels were decreased under 5% hypoxia in the brain tissue. In the recovery state, CNPase, S100b and NeuN levels were increased significantly in both the olfactory neuroepithelium and brain tissue in the 5% hypoxia group. The change in RNA activity in PCR was much higher in the 5% hypoxia group than in the 7% hypoxia group. CONCLUSIONS: Our findings suggest that IH damages the olfactory neuroepithelium and brain tissue in mouse model. The activity of olfactory marker genes and neurogenesis in the olfactory neuroepithelium were decreased. The levels of oxygen may be affect changes in the olfactory neuroepithelium. The olfactory ensheathing cell may be a major factor in the recovery of the olfactory neuroepithelium.

Olfactory Function and Depression: A Meta-Analysis.

OBJECTIVES: We investigated the relationship between olfactory function and depression and suggested future research in this area from rhinology. METHODS: We independently searched 5 databases (PubMed, SCOPUS, Embase, the Web of Science, and the Cochrane database) for recent studies published from December 2019 to the present. From the obtained studies, we reviewed the findings on olfactory function and depression using a questionnaire to measure depression and olfactory tests. RESULTS: The olfactory function test score based on the UPSIT-40 (standardized mean difference = -.37 [-.66; -.08], P = .0123) was significantly lower in the depression group than in the control group. The olfactory function score based on the Sniffin' sticks test for identification, discrimination, and threshold was lower in the depression group than in the control. A meta-analysis of the studies showed that depressed patients showed lower olfactory function than the control group. CONCLUSIONS AND SIGNIFICANCE: The findings revealed that an understanding of the relationship between olfaction and depression can be determined using an analysis methodology and a standardized olfactory test. Olfactory functioning and processing are highly integrated with emotion and memory through projections from the olfactory bulb to the central areas.

Role of systemic corticosteroids in orbital cellulitis: a meta-analysis and literature review.

INTRODUCTION: The standard management of orbital cellulitis is to administer a combination of intravenous broad-spectrum antibiotics along with treatment of associated sinusitis. OBJECTIVE: The purpose of this study was to evaluate whether the addition of corticosteroids could lead to earlier resolution of inflammation and improve disease outcome. METHODS: We independently searched five databases (PubMed, SCOPUS, Embase, the Web of Science, and the Cochrane database) for studies published as recent as December 2019. Of the included studies, we reviewed orbital cellulitis and disease morbidity through lengths of hospitalization, incidence of surgical drainage, periorbital edema, vision, levels or C-reactive protein, and serum WBC levels in order to focus on comparing steroid with antibiotics treated group and only antibiotics treated group. RESULTS: Lengths of hospitalization after admission as diagnosed as orbital cellulitis (SMD=-4.02 [-7.93; -0.12], p-value=0.04, I2=96.9%) decrease in steroid with antibiotics treated group compared to antibiotics only treated group. Incidence of surgical drainage (OR=0.78 [0.27; 2.23], p-value=0.64, I2=0.0%) was lower in the steroid with antibiotics treated group compared to the antibiotics only treated group. CONCLUSION: Use of systemic steroids as an adjunct to systemic antibiotic therapy for orbital cellulitis may decrease orbital inflammation with a low risk of exacerbating infection. Based on our analysis, we concluded that early use of steroids for a short period can help shorten hospitalization days and prevent inflammation progression.

Effects of Urban Particulate Matter on the Olfactory System in a Mouse Model.

BACKGROUND: Exposure to urban particulate matter (UPM) is linked to the aggravation of various health problems. Although the nasal cavity is the first barrier to encounter UPM, there is a lack of studies on the impact of UPM on the olfactory area. The purpose of this study was to investigate the cytotoxic effects of UPM on mouse olfactory epithelium, the underlying pathophysiology involved, and changes in cytokine levels. METHODS: Mice were divided into 4 groups: control, 400UPM (administered 400 µg UPM daily; standard reference material 1649b; average particle diameter 10.5 µm) 1week, 400UPM 2weeks, and recovery 1week after 400UPM 2weeks (n = 10, 6, 6, and 6, respectively). Olfactory function was evaluated by conducting a food-finding test once a week. The olfactory neuroepithelium was harvested for histologic examination, gene ontology, quantitative real-time polymerase chain reaction, and western blotting. RESULTS: Compared to those in the control group, olfactory marker protein, olfactory receptor 1507, adenylyl cyclase 3, and GNAL mRNA levels were lower and S-100, 2',3'-cyclic nucleotide 30-phosphodiesterase, nerve growth factor receptor-associated protein, brain-derived neurotrophic factor, and tachykinin receptor mRNA levels were higher in the 400UPM group olfactory neuroepithelium. There were no significant differences in neuroepithelial inflammatory marker levels between the 400UPM and saline group. CONCLUSIONS: UPM decreased olfactory function and might have cytotoxic effects on the olfactory epithelium. Olfactory ensheathing cells and trigeminal nerve might be related to the regeneration of the olfactory epithelium after olfactory destruction associated with UPM.

Taste Dysfunction after Tonsillectomy: A Meta-analysis.

OBJECTIVES: We aimed to provide information on the effects of tonsillectomy, in particular, its effects on taste dysfunction; also known as dysgeusia, and provide direction for future research in this area. METHODS: We independently searched five databases (PubMed, SCOPUS, Embase, the Web of Science, and the Cochrane database) for related studies published as recently as December 2019. From the included studies, we reviewed the findings on tonsillectomy and taste disturbance through the use of a questionnaire, chemogustometry, and electrogustometry. We analyzed other conditions that were measured in these studies that included; postoperative pain intensity and other morbidities (eg, postoperative bleeding, hemostasis, tongue numbness and zinc, copper, and iron hemoglobin levels measured). RESULTS: Postoperative taste disturbance based on questionnaire (VAS) scores at 14 days (SMD = -0.31 [-0.50, -0.12], P value = .0012) tended to decrease significantly in the post-tonsillectomy group compared to the pre-tonsillectomy group. Patients showed significantly decreased taste sensation after tonsillectomy than in the preoperative test. Postoperative electrogusmetry at 7 days (SMD = 0.60 [0.27, 0.94], P = .0004) tended to increase significantly in the post-tonsillectomy group compared to the pre-tonsillectomy group. CONCLUSION: Tonsillectomy is a commonly performed surgery, and taste disturbance occurs frequently as a post operative effect. Taste dysfunction is important to patients with regard to their quality of life and the overall effects of taste on their day-to-day life. This study can be a useful meta-analysis of dysgeusia in tonsillectomy.

Peripheral Nerve Regeneration Using a Nerve Conduit with Olfactory Ensheathing Cells in a Rat Model.

BACKGROUND: Autologous nerve grafts are the gold standard treatment for peripheral nerve injury treatment. However, this procedure cannot avoid sacrificing other nerves as a major limitation. The aim of the present study was to evaluate the potential of olfactory ensheathing cells (OECs) embedded in a nerve conduit. METHODS: A 10-mm segment of the sciatic nerve was resected in 21 rats, and the nerve injury was repaired with one of the following (n = 7 per group): autologous nerve graft, poly (ε-caprolactone) (PCL) conduit and OECs, and PCL conduit only. The consequent effect on nerve regeneration was measured based on the nerve conduction velocity (NCV), amplitude of the compound muscle action potential (ACMAP), wet muscle weight, histomorphometric analysis, and nerve density quantification. RESULTS: Histomorphometric analysis revealed nerve regeneration and angiogenesis in all groups. However, there were significant differences (p < 0.05) in the ACMAP nerve regeneration rate of the gastrocnemius and tibialis anterior muscles between the autologous graft (37.9 ± 14.3% and 39.1% ± 20.4%) and PCL only (17.8 ± 8.6% and 13.6 ± 5.8%) groups, and between the PCL only and PCL + OECs (46.3 ± 20.0% and 34.5 ± 14.6%) groups, with no differences between the autologous nerve and PCL + OEC groups (p > 0.05). No significant results in NCV, wet muscle weight, and nerve density quantification were observed among the 3 groups. CONCLUSION: A PCL conduit with OECs enhances the regeneration of injured peripheral nerves, offering a good alternative to autologous nerve grafts.