Comparing quality of recovery and satisfaction between spinal anesthesia and nerve block in orthopedic below-knee surgery: A prospective controlled trial.

BACKGROUND: Postoperative quality of recovery (QoR) and patient satisfaction have gained increasing significance in medical services. This study aimed to compare these 2 parameters between 2 types of regional anesthetics (spinal anesthesia and combined sciatic-femoral nerve block) in orthopedic lower knee surgery. METHODS: A total of 101 patients were classified into 2 groups (combined sciatic-femoral nerve block, group N; spinal anesthesia, group S) according to patient preference. In group N, sciatic and femoral nerve blocks were performed on the popliteal and groin regions, respectively, under ultrasound guidance. Spinal anesthesia was performed in group S. The primary outcomes were QoR and patient satisfaction. QoR was measured using the Korean translation of the QoR-15K. Patient satisfaction was assessed using an 11-point Likert scale (0-10) and a dichotomous question addressing anesthesia preferences for future surgeries. RESULTS: The physical independence of the postoperative QoR-15K was significantly higher in group N than in group S (14.2 vs 12.0, P = .04). On the 11-point Likert scale, group N scored 8.8, and group S scored 7.8 (P = .001). In the dichotomous question, 93.8% of the group N and 52.8% of the group S answered that they would like to choose the same anesthesia method for the next surgery (P < .001). In addition, fewer participants in group N complained of backache than those in group S, and the time to first urination after anesthesia was shorter in group N than in group S (P = .004, <.001, respectively). CONCLUSION: Combined sciatic-femoral nerve block may provide better physical independence and satisfaction than spinal anesthesia in orthopedic below-knee surgeries.

Emergence and genomic chion of Proteus mirabilis harboring blaNDM-1 in Korean companion dogs.

Proteus mirabilis is a commensal bacterium dwelling in the gastrointestinal (GI) tract of humans and animals. Although New Delhi metallo-ß-lactamase 1 (NDM-1) producing P. mirabilis is emerging as a threat, its epidemiology in our society remains largely unknown. LHPm1, the first P. mirabilis isolate harboring NDM-1, was detected from a companion dog that resides with a human owner. The whole-genome study revealed 20 different antimicrobial resistance (AMR) genes against various classes of antimicrobial agents, which corresponded to the MIC results. Genomic regions, including MDR genes, were identified with multiple variations and visualized in a comparative manner. In the whole-genome epidemiological analysis, multiple phylogroups were identified, revealing the genetic relationship of LHPm1 with other P. mirabilis strains carrying various AMR genes. These genetic findings offer comprehensive insights into NDM-1-producing P. mirabilis, underscoring the need for urgent control measures and surveillance programs using a "one health approach".

Predictors for Dexmedetomidine Requirement for Sedation under Regional Anesthesia.

(1) Background: This prospective observational study aimed to investigate the predictors affecting DMT requirements for sedation during regional anesthesia. (2) Method: A total of 108 patients who received regional anesthesia with intravenous DMT administration for orthopedic upper- or lower-extremity surgery were enrolled. Following successful regional anesthesia, DMT was administered at a rate of 4 µg/kg/h until reaching loss of consciousness (LOC). The administered dose of DMT per body weight until LOC (DMTLOC; µg/kg) was evaluated. The infusion was maintained at a rate of 0.2-0.7 µg/kg/h during the surgery. At the end of surgery, the elapsed time to a BIS value of 90 (TBIS90; s) was recorded. Linear regression models were used to identify potential predictors of DMTLOC and TBIS90. (3) Results: One hundred patients were analyzed. There were negative relationships between DMTLOC and age (r = -0.297, p = 0.003) and DMTLOC and body mass index (BMI) (r = -0.425, p < 0.001), respectively. Multiple linear regression models revealed that both increasing age and BMI were significantly related to DMTLOC (r2 = 0.259, p < 0.001), but those variables showed no association with TBIS90. (4) Conclusions: The results of this study suggest that initial loading of DMT should be carefully titrated to minimize risk in elderly and obese surgical populations.

Identification of maximal tumor size associated with negligible lymph node metastasis for endoscopic submucosal dissection of undifferentiated-type early gastric cancer.

BACKGROUND AND AIMS: When treating undifferentiated-type early gastric cancer (UD-EGC) that is limited to the mucosa (clinically T1a), endoscopic submucosal dissection (ESD) can be considered if the tumor is 2 cm or less and is not ulcerated. However, there is insufficient evidence to determine the relationships between tumor size and oncological safety of ESD in UD-EGC. METHODS: The pathology reports of Korean patients who were diagnosed with UD-EGC (n = 5286) were retrospectively reviewed. The cumulative incidence of lymph node metastasis (LNM) according to tumor size was evaluated in subgroups. The tumor-size cut-off was identified as the upper limit of the 95% confidence interval (CI) of cumulative LNM incidence that did not exceed 1.0%. RESULTS: We identified 1516 patients with non-ulcerated T1a tumors ≤2 cm in size. Among patients without lymphatic invasion, 1.5% (95% CI 0.91-2.16%) had LNM. In patients with poorly differentiated tubular adenocarcinoma (PD), LNM increased from 0 to 0.74% based on a tumor size of 1.0 cm. Regardless of tumor size, smaller percentages of undifferentiated-type (UD) and poorly cohesive carcinoma (PCC) patients experienced LNM than did those with PD. In non-ulcerated mucosal cancer without lymphatic invasion and tumor size ≤0.9 cm, no LNM was observed in patients with UD (95% CI 0-0.53%), PCC (95% CI 0-0.59%), or PD (95% CI 0-0.86%) histologic type. CONCLUSION: In patients diagnosed with non-ulcerated T1a UD-EGC, ESD can be performed if the tumor size is 0.9 cm or less, regardless of histologic type.

Insufficient nutrient intake in individuals with disabling hearing loss and the restoration of nutritional sufficiency in hearing aid users.

Hearing loss affects some nutrient intake. Disabling hearing loss may exacerbate these issues. We aimed to evaluate nutrient intake and assess deficiencies based on functional hearing status. The study included 6907 participants with information on demographic factors, nutrient intake, weight, height, disease status, and hearing level in the eighth Korea National Health and Nutrition Examination Survey, conducted from 2019 to 2021. We categorized the participants into 3 groups based on their functional hearing status: bilateral hearing, unilateral hearing, and disabling hearing loss. The disabling hearing loss group showed lower intake of most major nutrients (P < 0.05), dietary fiber (P < 0.001), and most minerals and vitamins (P < 0.05), with some insufficiencies. The unilateral hearing group showed lower intake only for potassium (P = 0.036) compared to the bilateral hearing group and significantly higher intake of hydration (P = 0.039), dietary fiber (P = 0.039), and calcium (P = 0.009) than the disabling hearing loss group. Nutrient insufficiency in the disabling hearing loss group was more prominent in women, and was partially resolved by using hearing aids. Clinicians and nutritionists should consider undernourishment in these patients, and appropriate interventions for nutrition and hearing aids should be recommended.

Strategies for Overcoming Immune Evasion in Bladder Cancer.

Tumors intricately shape a highly immunosuppressive microenvironment, hampering effective antitumor immune responses through diverse mechanisms. Consequently, achieving optimal efficacy in cancer immunotherapy necessitates the reorganization of the tumor microenvironment and restoration of immune responses. Bladder cancer, ranking as the second most prevalent malignant tumor of the urinary tract, presents a formidable challenge. Immunotherapeutic interventions including intravesical BCG and immune checkpoint inhibitors such as atezolizumab, avelumab, and pembrolizumab have been implemented. However, a substantial unmet need persists as a majority of bladder cancer patients across all stages do not respond adequately to immunotherapy. Bladder cancer establishes a microenvironment that can actively hinder an efficient anti-tumor immune response. A deeper understanding of immune evasion mechanisms in bladder cancer will aid in suppressing recurrence and identifying viable therapeutic targets. This review seeks to elucidate mechanisms of immune evasion specific to bladder cancer and explore novel pathways and molecular targets that might circumvent resistance to immunotherapy.

Relationship between Serum Total Testosterone Concentration and Metabolic Syndrome in Premenopausal Obese Women.

Background: Men with low testosterone levels are at an increased risk of developing metabolic syndrome, irrespective of age or obesity. However, the relationship between metabolic syndrome and testosterone levels in women remains unclear. We compared the total testosterone concentrations between premenopausal obese women with and without metabolic syndrome and identified the factors affecting these concentrations. Methods: A single-center retrospective analysis was conducted using the medical records of 580 premenopausal women with obesity. The diagnostic criteria for metabolic syndrome were established using the National Cholesterol Education Program Adult Treatment Panel III guidelines. Results: The mean±standard deviation age, weight, and body mass index were 38.8±8.4 years, 78.0±11.8 kg, and 30.0±4.1 kg/m2, respectively. The mean total testosterone concentration was lower in the metabolic syndrome group than in the non-metabolic syndrome group (n=385 vs. n=195; 0.22±0.10 ng/mL vs. 0.24±0.11 ng/mL; P<0.001). In a model adjusted for age, body mass index, skeletal muscle mass, body fat mass, and body fat percentage, the odds ratio for metabolic syndrome with respect to the total testosterone level was 0.128 (P=0.028). Testosterone concentration was negatively correlated with age (r=-0.334), systolic blood pressure (r=-0.084), and triglyceride concentration (r=-0.093) but positively correlated with weight (r=0.144), body mass index (r=0.140), waist circumference (r=0.133), body fat mass (r=0.167), and body fat percentage (r=0.167). Stepwise regression analysis revealed that age (ß=-0.004, P<0.001), body mass index (ß=0.003, P=0.004), and high-density lipoprotein cholesterol concentration (ß=0.001, P=0.019) were independently associated with total testosterone concentration (adjusted R2=12.6%). Conclusion: Metabolic syndrome and obesity may be independently associated with testosterone levels in premenopausal women with obesity.

Surgical Correction of Left Ventricular Assist Device Outflow Graft Obstruction Caused by a Wrapped Expanded Polytetrafluoroethylene Graft: A Case Report.

A 70-year-old man with dilated cardiomyopathy underwent left ventricular assist device (LVAD) implantation, using a HeartWare ventricular assist device, as a bridge to candidacy. After 26 months, computed tomography (CT) angiography indicated stenosis in the LVAD outflow graft; however, the patient was asymptomatic, prompting a decision to manage his condition with close monitoring. Ten months later, the patient presented with dizziness and low-flow alerts. Subsequent CT angiography revealed a critical obstruction involving the entire LVAD outflow graft. The patient underwent emergency surgery, during which an organized seroma causing the graft obstruction was found between a wrapped expanded polytetrafluoroethylene (ePTFE) graft and a Dacron outflow graft. The covering of the outflow graft was removed, along with the organized seroma. Following removal of the ePTFE wrap and decompression of the outflow graft, normal LVAD flow was reestablished. The practice of wrapping the outflow graft with synthetic material, commonly done to facilitate later redo sternotomy, may pose a risk for outflow graft obstruction.

Association of Range of Motion Deficit and Recurrence of Pain After Treatment of Adhesive Capsulitis.

INTRODUCTION: We evaluated the factors influencing the duration of significant pain reduction after conservative management for adhesive capsulitis (AC). METHODS: Follow-up for 6-8 months was performed with 141 patients with AC who experienced significant pain reduction after treatment. Clinical and demographic factors, numeric rating scale (NRS) scores, and shoulder range of motion (ROM) were collected and assessed pretreatment (T0), at 5 weeks post-treatment (T1), and at 6-8 months post-treatment (T2). Patients were divided into successful (n = 96) and unsuccessful (n = 45) NRS groups according to the degree of pain reduction at T2. We assessed post-treatment NRS and ROM improvement scores within each group and compared these parameters between the two groups. RESULTS: Significant NRS and ROM improvements were achieved in all patients who participated in our study. The unsuccessful NRS group demonstrated a lack of significant improvement in abduction at T1 and T2. All T1 and shoulder ROM measurements among the unsuccessful NRS group were significantly smaller than those among the successful NRS group. CONCLUSIONS: Failure to achieve a significant improvement in abduction angle after conservative management of AC was significantly associated with pain recurrence.

Adipose tissue-derived exosomes alleviate particulate matter-induced inflammatory response and skin barrier damage in atopic dermatitis-like triple-cell model.

Recently, particulate matter (PM) has been shown to exacerbate atopic dermatitis (AD) by inducing an inflammatory response. Meanwhile, several studies revealed that exosomes derived from adipose tissue-derived mesenchymal stem cells promote wound healing and alleviate inflammation via their regenerative and immunomodulatory capacities. Our study aimed to investigate the effects of human adipose tissue-derived mesenchymal stem cell-derived (ASC)-exosomes in PM-induced AD. An AD-like triple-cell model was established by treating human keratinocytes, dermal fibroblasts, and mast cells with polyinosinic:polycytidylic acid (Poly I:C) and interleukin 1 alpha (IL-1α). The effects of PM and ASC-exosomes on the expression of pro-inflammatory cytokines and skin barrier proteins were examined using quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. PM increased pro-inflammatory cytokines (IL-6, IL-1ß, and IL-1α) and decreased the anti-inflammatory cytokine IL-10, while the mRNA expression of skin barrier proteins (loricrin and filaggrin) decreased. However, when the cells were treated with ASC-exosomes, the PM-induced effects on pro-inflammatory cytokines and skin barrier proteins were reversed. Our results confirmed that PM-induced inflammation and skin barrier damage were alleviated by ASC-exosomes in our AD-like triple-cell model. These data suggest that ASC-exosomes can serve as a therapeutic agent for PM-exacerbated AD.

Tailored radiation dose according to margin width for patients with ductal carcinoma in situ after breast-conserving surgery.

A 2 mm resection margin is considered adequate for ductal carcinoma in situ (DCIS). We assessed the effectiveness of a tailored radiation dose for margins < 2 mm and the appropriate margin width for high-risk DCIS. We retrospectively evaluated 137 patients who received adjuvant radiotherapy after breast-conserving surgery for DCIS between 2013 and 2019. The patients were divided into three- positive, close (< 2 mm), and negative (≥ 2 mm) margin groups. Radiation dose to the tumor bed in equivalent dose in 2 Gy fractions were a median of 66.25 Gy, 61.81 Gy, and 59.75 Gy for positive, close, and negative margin groups, respectively. During a median follow-up of 58 months, the crude rates of local recurrence were 15.0%, 6.7%, and 4.6% in the positive, close, and negative margin groups, respectively. The positive margin group had a significantly lower 5-year local recurrence-free survival (LRFS) rate compared to the close and negative margin groups in propensity-weighted log-rank analysis (84.82%, 93.27%, and 93.20%, respectively; p = 0.008). The difference in 5-year LRFS between patients with the high- and non-high-grade tumors decreased as the margin width increased (80.4% vs. 100.0% for margin ≥ 2 mm, p < 0.001; 92.3% vs. 100.0% for margin ≥ 6 mm, p = 0.123). With the radiation dose tailored for margin widths, positive margins were associated with poorer local control than negative margins, whereas close margins were not. Widely clear margins (≥ 2 mm) were related to favorable local control for high-grade DCIS.

Complete microbial synthesis of crocetin and crocins from glycerol in Escherichia coli.

BACKGROUND: Crocin, a glycosylated apocarotenoid pigment predominantly found in saffron, has garnered significant interest in the field of biotechnology for its bioactive properties. Traditional production of crocins and their aglycone, crocetin, typically involves extraction from crocin-producing plants. This study aimed to develop an alternative biosynthetic method for these compounds by engineering the metabolic pathways of zeaxanthin, crocetin, and crocin in Escherichia coli strains. RESULTS: Employing a series of genetic modifications and the strategic overexpression of key enzymes, we successfully established a complete microbial pathway for synthesizing crocetin and four glycosylated derivatives of crocetin, utilizing glycerol as the primary carbon source. The overexpression of zeaxanthin cleavage dioxygenase and a novel variant of crocetin dialdehyde dehydrogenase resulted in a notable yield of crocetin (34.77 ± 1.03 mg/L). Further optimization involved the overexpression of new types of crocetin and crocin-2 glycosyltransferases, facilitating the production of crocin-1 (6.29 ± 0.19 mg/L), crocin-2 (5.29 ± 0.24 mg/L), crocin-3 (1.48 ± 0.10 mg/L), and crocin-4 (2.72 ± 0.13 mg/L). CONCLUSIONS: This investigation introduces a pioneering and integrated microbial synthesis method for generating crocin and its derivatives, employing glycerol as a sustainable carbon feedstock. The substantial yields achieved highlight the commercial potential of microbial-derived crocins as an eco-friendly alternative to plant extraction methods. The development of these microbial processes not only broadens the scope for crocin production but also suggests significant implications for the exploitation of bioengineered compounds in pharmaceutical and food industries.

The Potentiality of Natural Products and Herbal Medicine as Novel Medications for Parkinson's Disease: A Promising Therapeutic Approach.

As the global population ages, the prevalence of Parkinson's disease (PD) is steadily on the rise. PD demonstrates chronic and progressive characteristics, and many cases can transition into dementia. This increases societal and economic burdens, emphasizing the need to find effective treatments. Among the widely recognized causes of PD is the abnormal accumulation of proteins, and autophagy dysfunction accelerates this accumulation. The resultant Lewy bodies are also commonly found in Alzheimer's disease patients, suggesting an increased potential for the onset of dementia. Additionally, the production of free radicals due to mitochondrial dysfunction contributes to neuronal damage and degeneration. The activation of astrocytes and the M1 phenotype of microglia promote damage to dopamine neurons. The drugs currently used for PD only delay the clinical progression and exacerbation of the disease without targeting its root cause, and come with various side effects. Thus, there is a demand for treatments with fewer side effects, with much potential offered by natural products. In this study, we reviewed a total of 14 articles related to herbal medicines and natural products and investigated their relevance to possible PD treatment. The results showed that the reviewed herbal medicines and natural products are effective against lysosomal disorder, mitochondrial dysfunction, and inflammation, key mechanisms underlying PD. Therefore, natural products and herbal medicines can reduce neurotoxicity and might improve both motor and non-motor symptoms associated with PD. Furthermore, these products, with their multi-target effects, enhance bioavailability, inhibit antibiotic resistance, and might additionally eliminate side effects, making them good alternative therapies for PD treatment.

Pericardial Window Operation in Oncology Patients: Analysis of Long-Term Survival and Prognostic Factors.

Background: Pericardial effusion (PE) is a serious condition in cancer patients, primarily arising from malignant dissemination. Pericardial window formation is a surgical intervention for refractory PE. However, the long-term outcomes and factors associated with postoperative survival remain unclear. Methods: We retrospectively analyzed data from 166 oncology patients who underwent pericardial window formation at Samsung Medical Center between 2011 and 2023. We analyzed survival and PE recurrence regarding surgical approach, cancer type, and cytopathological findings. To identify factors associated with survival, we utilized Cox proportional-hazards regression. Results: All patients had tumors documented in accordance with the American Joint Committee on Cancer staging manual, including lung (61.4%), breast (9.6%), gastrointestinal (9.0%), hematologic (3.6%), and other cancers (16.4%). Surgical approaches included mini-thoracotomy (67.5%) and thoracoscopy (32.5%). Postsurgical cytopathology confirmed malignancy in 94 cases (56.6%). Over a median follow-up duration of 50.0 months, 142 deaths and 16 PE recurrences occurred. The 1-year overall and PE recurrence-free survival rates were 31.4% and 28.6%, respectively. One-year survival rates were significantly higher for thoracoscopy recipients (43.7% vs. 25.6%, p=0.031) and patients with negative cytopathology results (45.1% vs. 20.6%, p<0.001). No significant survival difference was observed between lung cancer and other types (p=0.129). Multivariate analysis identified New York Heart Association class, cancer stage, and cytopathology as independent prognostic factors. Conclusion: This series is the largest to date concerning window formation among cancer patients with PE. Patients' long-term survival after surgery was generally unfavorable. However, cases with negative cytopathology or earlier tumor stage demonstrated comparatively high survival rates.

Biosafety and potency of high-molecular-weight hyaluronic acid with intratympanic dexamethasone delivery for acute hearing loss.

Objective: This study evaluated the potential of high-molecular-weight hyaluronic acid (HHA) as an intratympanic (IT) drug delivery vehicle for dexamethasone (D) in treating acute hearing loss. We compared the efficacy, safety, and residence time of HHA to the standard-of-care IT drug delivery method. Methods: Endoscopic examinations were used to track tympanic membrane (TM) healing post-IT injection. Micro-computed tomography (CT) was used to gauge drug/vehicle persistence in the bulla air space. Histological analyses covered the middle ear, TM, and hair cell counts. Auditory brainstem responses (ABR) were used to measure hearing thresholds, while high-performance liquid chromatography (HPLC) was employed to quantify cochlear perilymph dexamethasone concentrations. Results: The HHA + D group had a notably prolonged drug/vehicle residence time in the bulla (41 ± 27 days) compared to the saline + D group (1.1 ± 0.3 days). Complete TM healing occurred without adverse effects. Histology revealed no significant intergroup differences or adverse outcomes. Hearing recovery trends favored the HHA + D group, with 85.0% of ears showing clinically meaningful improvement. D concentrations in cochlear perilymph were roughly double in the HHA group. Conclusion: HHA is a promising vehicle for IT drug delivery in treating acute hearing loss. It ensures extended residence time, augmented drug concentrations in targeted tissues, and safety. These results highlight the potential for HHA + D to excel beyond existing standard-of-care treatments for acute hearing loss.

The Anti-Inflammatory Effects of Adipose Tissue Mesenchymal Stem Cell Exosomes in a Mouse Model of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a group of chronic, relapsing inflammatory disorders that affect the gastrointestinal tract, with the primary subtypes being ulcerative colitis (UC) and Crohn's disease (CD). We aimed to evaluate the therapeutic potential of extracellular vesicles released by adipose-tissue-derived mesenchymal stem cells, which we, in this manuscript, call "exosomes" (ASC-EXOs), in a mouse model of IBD. We specifically aimed to determine the effectiveness of different treatment protocols and compare the effects with that of anti-IL-12 p40 monoclonal antibody. The addition of dextran sulfate sodium (DSS) to drinking water induced multiple signs of IBD, including weight loss, soft stool, and bloody feces. ASC-EXOs given by either intraperitoneal (IP) or intravenous (IV) routes resulted in moderate improvement in these signs of IBD. IV ASC-EXOs resulted in significantly reduced body weight loss, improved histopathological scoring, and suppressed the disease activity index (DAI) compared to the IBD control group. Also, a reduction in PCR for pro-inflammatory cytokines was observed. IV ASC treatment resulted in dose-related reduction in IBD signs, including weight loss. An increasing number of injections with ASC-EXOs reduced histopathological scores as well as DAI. Co-administration of ASC-EXOs with anti-IL-12 p40 significantly decreased DAI scores in the ASC-EXO + anti-IL-12 p40 group. In conclusion, ASC-EXOs have potential as a therapeutic agent for IBD, but the route of administration, number of injections, and dosage need to be considered to optimize the effects of ASC-EXO treatment. This study also highlights the potential benefits of combination therapies of ASC-EXOs and anti-IL-12. Our findings pave the way for further studies to unravel the underlying therapeutic mechanisms of ASC-EXOs in IBD treatment.

Novel autosomal dominant TMC1 variants linked to hearing loss: insight into protein-lipid interactions.

BACKGROUND: TMC1, which encodes transmembrane channel-like protein 1, forms the mechanoelectrical transduction (MET) channel in auditory hair cells, necessary for auditory function. TMC1 variants are known to cause autosomal dominant (DFNA36) and autosomal recessive (DFNB7/11) non-syndromic hearing loss, but only a handful of TMC1 variants underlying DFNA36 have been reported, hampering analysis of genotype-phenotype correlations. METHODS: In this study, we retrospectively reviewed 338 probands in an in-house database of genetic hearing loss, evaluating the clinical phenotypes and genotypes of novel TMC1 variants associated with DFNA36. To analyze the structural impact of these variants, we generated two structural models of human TMC1, utilizing the Cryo-EM structure of C. elegans TMC1 as a template and AlphaFold protein structure database. Specifically, the lipid bilayer-embedded protein database was used to construct membrane-embedded models of TMC1. We then examined the effect of TMC1 variants on intramolecular interactions and predicted their potential pathogenicity. RESULTS: We identified two novel TMC1 variants related to DFNA36 (c.1256T > C:p.Phe419Ser and c.1444T > C:p.Trp482Arg). The affected subjects had bilateral, moderate, late-onset, progressive sensorineural hearing loss with a down-sloping configuration. The Phe419 residue located in the transmembrane domain 4 of TMC1 faces outward towards the channel pore and is in close proximity to the hydrophobic tail of the lipid bilayer. The non-polar-to-polar variant (p.Phe419Ser) alters the hydrophobicity in the membrane, compromising protein-lipid interactions. On the other hand, the Trp482 residue located in the extracellular linker region between transmembrane domains 5 and 6 is anchored to the membrane interfaces via its aromatic rings, mediating several molecular interactions that stabilize the structure of TMC1. This type of aromatic ring-based anchoring is also observed in homologous transmembrane proteins such as OSCA1.2. Conversely, the substitution of Trp with Arg (Trp482Arg) disrupts the cation-π interaction with phospholipids located in the outer leaflet of the phospholipid bilayer, destabilizing protein-lipid interactions. Additionally, Trp482Arg collapses the CH-π interaction between Trp482 and Pro511, possibly reducing the overall stability of the protein. In parallel with the molecular modeling, the two mutants degraded significantly faster compared to the wild-type protein, compromising protein stability. CONCLUSIONS: This results expand the genetic spectrum of disease-causing TMC1 variants related to DFNA36 and provide insight into TMC1 transmembrane protein-lipid interactions.