Structural Anatomy

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    A Qualitative Histological Comparison of Collagen Deposition Between a Diseased and Healthy Cadaveric Heart
    (2023) Shah, Krusha; Snyder, Alyssa; Markgraf, Jon Michael; Sarathy, Swathi; Kronser, Leo; Crowe, Nicole
    Purpose: Fibrosis is a pathological process characterized by the overproduction of extracellular matrix (ECM), especially collagen. Type I collagen is the most abundant structural protein found in ECM and serves as an indicator for fibrosis. Although increased collagen accumulation is considered a normal aspect of aging, excessive collagen accumulation is also a notable hallmark observed in chronic cardiovascular disease. Numerous studies have examined collagen deposition using animal models and pathologic human cardiac tissue. However, few studies have investigated the normal accumulation of collagen in healthy human hearts. This study aims to perform a qualitative comparison of collagen deposition between a diseased and healthy human heart. Methods and Results: This study utilized two hearts from cadaveric donors, one designated "diseased” and the other "healthy”. Each heart originated from a female in their 6th decade of life and had a body mass index within the normal range (18.5-24.9 kg/m2). The donor with the "diseased” heart had a known history of heart disease. Furthermore, gross examination revealed the "diseased” heart was enlarged (mass: 458.5 g; normal range: 230-290 g), had severe coronary artery disease, contained two implanted coronary artery grafts, and demonstrated left ventricular wall hypertrophy (thickness: 2.0 cm; normal thickness: ≤1.5 cm). In contrast, the donor with the "healthy” heart had no known history of heart disease and showed no visible signs of disease. Tissue samples were collected from the right ventricle, interventricular septum, and left ventricle from each heart and underwent routine histological preparation with Masson’s trichrome staining. Microscopic observation was performed to determine the pattern of collagen deposition within each section, classified as interstitial-perimyocyte, replacement, or mixed. Additionally, the location of collagen in each section of the ventricular wall was noted as being primarily within the inner 50% (endocardial side), outer 50% (epicardial side), or diffuse. To assess the reliability and repeatability of this study, an analysis of intra- and interobserver error will be conducted by the authors. Preliminary findings suggest the amount and patterns of collagen differs between the two hearts. Conclusion: In this study, histology was used to qualitatively analyze the differences in collagen deposition between a diseased and healthy human heart. These findings highlight the importance of conducting a comprehensive study that examines the normal accumulation of collagen in healthy human hearts. Gaining an in-depth understanding of how collagen accumulates normally is critical for recognizing disease related changes.
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    Contrast-enhanced micro-CT approaches for visualizing musculoskeletal development in neonatal mice
    (2023) Stalls, Javan; Miller, Courtney; Gonzales, Lauren; Lesciotto, Kate; Handler, Emma; Organ, Jason; Menegaz, Rachel A.
    Contrast-enhanced micro-CT approaches for visualizing musculoskeletal development in neonatal mice Javan A. Stalls, Courtney A. Miller, Jason M. Organ, Emma K. Handler, Lauren A. Gonzales, Kate M. Lesciotto, Rachel A. Menegaz Purpose: While there are many forms of radiological imaging that can be used to gather anatomical data from biological specimens, computed tomography (CT) imaging has been the gold standard for visualizing dense tissue, such as bone, with detailed resolution. However, this imaging modality is not well suited for soft tissues (muscle, brain, abdominal organs, cartilage, etc.) due to their decreased tissue density. The inability to distinguish between soft tissues in CT scans limits our ability to investigate the bone-muscle interactions known to stimulate and direct bone modeling during early postnatal development. The development of contrast-enhancing staining agents, capable of binding materials to increase their radiodensity, has allowed for more accurate and enhanced visualizations of less dense soft tissues, such as muscle and brain structures. Contrast agents such as iodine have differential affinities for the different soft tissues in the body allowing for easier visualization and segmentation of soft tissues in relation to the skeleton. Previous studies have used contrast-enhanced CT (CE-CT) scanning to analyze early development of mice from prenatal stages to postnatal day 7. However, additional CE-CT imaging during the first three postnatal weeks is needed to understand muscle-bone interactions during critical periods of behavioral development, such as suckling and weaning. The goal of this project is to develop a CE-CT protocol and corresponding anatomical atlas showing the development of skeletal and soft tissue structures in the crania of neonatal mice from birth to weaning. Methods: Neonatal and preweaning mice (B6C3Fe a/a-Col1a2OIM/J) were euthanized on day of birth (P0), postnatal day 7 (P7), and postnatal day 14 (P14). Ethanol-fixed tissues were submerged in 1.25% iodine in 70% ethanol (I2E) for 2-14 days, with the skin intact in order to preserve cutaneous musculature. Both pre-stained and post-stained tissues were scanned using a MRS CT-80 micro-CT machine (20 µm3 voxel resolution). Results: Preliminary CE-CT scans following 10 days in an iodine stain present improved visualization of soft tissue (brain structures, cranial muscles, salivary glands) when compared to the baseline bone CT scans. Conclusion: These scans will be used to develop 3D models of musculoskeletal ontogeny from birth-weaning, providing insights into this critical developmental period. The use of CT contrast agents such as iodine offers new opportunities to investigate the anatomical interactions of bone and muscle during early development, and can be applied to investigate models of both normal growth and pathological disorders affecting musculoskeletal growth.
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    Deep Profunda Femoris variant found within the Sciatic Sheath supplying the posterior compartment of the leg
    (2023) Driskill, Austin; Fowers, Rylan; Craig, Taylor; Lovely, Rehana S.
    Abstract The lower extremity has well documented arterial variations; however, finding an artery within the sciatic sheathing and providing muscular branches to the proximal leg is abnormal. During the dissection of a 64-year-old male cadaver, a branch of the deep femoral artery was found within the sciatic sheath of the lower right extremity in the posterior compartment. Knowledge of the branches of the femoral and deep femoral arteries is clinically relevant in radiology nerve blocking treatment and surgically relevant in knee and femoral surgeries. The deep femoral artery branches off the femoral artery on the proximal portion of the anteriomedial side of the thigh. Deep to the rectus femoris muscle and between the vastus medialis muscle and adductor magnus muscle, the deep femoral artery provides perforating branches that give off cutaneous, anastomotic, and muscular branches to the flexor aspect of the thigh. The variant artery in this cadaver was found as an enlarged perforating branch of the profunda femoris artery, piercing through the adductor magnus muscle and supplying the posterior compartment of the thigh. Perforating branches commonly terminate in the posterior thigh, but this variant continues through the posterior leg and popliteal fossa within the sciatic sheath. The variant blood vessel terminates distal to the knee as muscular branches for both heads of the gastrocnemius and soleus muscles.
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    Accessory Muscle from the Trapezius Muscle into the Thoracolumbar Fascia
    (2023) Kara, Ramiz; Tran, Lianna; Vasilev, Viktor; Luu, Dustin
    Background: As part of the superficial back musculature, the trapezius and latissimus dorsi muscles play an integral role in upper body mobility. The trapezius functions in neck extension and movement of the scapula, allowing motions such as elevation, depression, upward rotation, and retraction. The latissimus dorsi functions to internally rotate, adduct, and extend the arm. Anatomical variations of these muscles have been previously reported in literature and are associated with aplasia, hypoplasia, agenesis, and variations in vasculature and innervation. Case Information: We present our discovery of a unique trapezius muscle variant that was discovered upon standard cadaveric dissection. The variant is approximately 6.0 cm in length. The accessory muscle is observed to originate from the inferolateral fibers of the trapezius and inserts into the superomedial fibers of the latissimus dorsi muscle. The inferior aspect of the muscle-tendon runs continuously with the latissimus dorsi muscle tendon, ultimately inserting into the thoracolumbar fascia. The superior aspect of the muscle belly narrows to fuse with the deep surface of the trapezius muscle. The middle portion of the accessory muscle was surrounded by its own fascial sheath, separating it from both the superficial cutaneous tissue and the deep musculature. Conclusion: Anatomical variants arise commonly in individuals, and their clinical significance - especially in the routinely used upper body muscles - can either impair quality of life or be asymptomatic. More specifically, accessory muscle variants, like the one we found, are important to note due to their use in surgical procedures, relevance during diagnostic imaging, and their potential for clinical manifestations (such as pain syndromes and scoliosis). We suggest that accessory muscle variants could offer alternative options to surgeons when considering tendon transfer procedures. Next, we propose that the presence of a unilateral accessory muscle could play a role in scoliosis. The trapezius and paraspinal muscles, and their connections with the spinal vertebrae, contribute to the balance of forces that, when imbalanced, may present as idiopathic scoliosis. Previous studies have shown that abnormalities in the paraspinal muscles, like the trapezius, have a strong correlation with idiopathic scoliosis. Lastly, we suggest the presence of unilateral accessory muscles may give rise to pain symptoms.
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    SPHARM, a New Computational Approach for Locomotor Signal Identification in 15 MYA fossil primates from Maboko Island, Kenya
    (2023) Thompson, Indya; Arney, Irisa; Perchalski, Bernadette; Ratkowski, Jakub; Benefit, Brenda; McCrossin, Monte; Gonzales, Lauren
    Purpose: Maboko Island, western Kenya preserves a diverse collection of seven catarrhine proximal humeri from the middle Miocene (~15 Ma). Proximal humeri are extremely rare in the Miocene (25-5 mya), limited to only four specimens outside of Maboko. Identified taxa include cercopithecoids (Victoriapithecus), nyanzapithecines (Mabokopithecus), small-bodied "apes” ("Micropithecus”), and large-bodied hominoids (Kenyapithecus), all of which provide important insight into diversity of locomotor patterns among middle Miocene catarrhines. Methods: This project uses weighted spherical harmonics analysis (SPHARM), a landmark-free automated method to explore locomotor signals in the Maboko sample. Meshes of five intact humeri were compared to a sample of 94 extant catarrhines and platyrrhines, spanning a range of locomotor modes (suspensory arborealism, terrestrial quadrupedalism, arboreal quadrupedalism, and knuckle walking). Principal components analyses (PCA) were run on the associated SPHARM coefficients to explore differences among these locomotor groups. Results: Preliminary assessment shows extant suspensory arboreal primates clustering away from both knuckle-walking and quadrupedal group along PC1 and PC2. Along PC2, further separation was observed between arboreal and terrestrial quadrupeds. The Maboko specimens show distinctions between all five of the fossil primates, particularly between two taxa previously suggested to be arboreal (Mabokopithecus and "Micropithecus”) and two taxa documented as terrestrial quadrupeds (Victoriapithecus and Kenyapithecus). Conclusion: Though preliminary, this analysis provides insight into the diversity of catarrhine locomotor behavior during the middle Miocene, reinforcing previous descriptions of locomotor partitioning among the Maboko specimens. Future research that includes early and late Miocene taxa may shed light into diversity of catarrhine locomotor behaviors that spanned the Miocene epoch.
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    Lymphatic Malformation Discovered Post-Tonsillectomy in a 5-Year-Old Female
    (2023) Khurshid, Bilal; Marcincuk, Michelle
    Abstract Presenter: Bilal Khurshid Authors: Bilal Khurshid OMS-II, Michelle Marcincuk, MD Title: Lymphatic Malformation Discovered Post-Tonsillectomy in a 5-Year-Old Female Background: Lymphatic malformations (LM) are benign tumors of the lymphatic vessels that are a result of congenital abnormalities in the lymphatic system. They are found most in children younger than the age of 2 and are frequently localized in the head and neck regions. Despite being benign, LM still have potential for invasion, so they should still be monitored after discovery. Case Information: A 5-year-old female presented to her otolaryngologist with recurrent serous otitis of both ears and enlarged tonsils and adenoids. The physician then performed a bilateral myringotomy with tube placement, and a tonsillectomy/adenoidectomy. A few days after the tonsillectomy, she presented with significant swelling, fever, lymphadenitis, and a large, layered fluid collection localized over the right side of her face and neck. The swelling was drained by interventional radiology; and then, an MRI was performed, which showed large cystic structures around the right parotid gland, temporomandibular joint, and pharyngeal area that was consistent with a LM. Conclusion: Lymphatic malformations are primarily diagnosed in children. In this case, both the location and the method of discovery of this structure were uncommon. This LM was found in the parapharyngeal space, right next to the tonsil. Typically, LMs are not found this high in the head and neck region. Furthermore, this LM was likely only found due to the preceding tonsillectomy/adenoidectomy, which may have introduced an infectious nidus to the structure causing it to become inflamed and causing systemic symptoms in the patient. This case illustrates that the parapharyngeal space should be considered for LM and an infectious nidus post-surgery may lead to systemic symptoms. The treatment involved incision and drainage, with subsequent follow up with hematology/oncology for further clinical management.
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    Unilateral Levator Scapulae Anatomical Variants
    (2023) Luu, Dustin; Frangenberg, Alexander; Vasilev, Viktor; Tran, Lianna; Kara, Ramiz; Fisher, Cara
    Background: Neck pain constitutes 13.8% of chief complaints. Causes of neck pain, including Levator Scapulae Syndrome (LPS), have become increasingly important and warrant discussion of contributing factors, such as anatomical variations. We present two discovered anatomical variants of the levator scapulae (LS) muscle. Awareness of the variation in LS accessory muscles may be relevant in differentiating between normal and pathological diagnoses, while remaining a possible target of therapy in pain syndromes, such as LPS. Case Information: Routine cadaveric dissection of a 41-year-old female and a 50-year-old male donor was performed. Upon dissection of the superficial back of both cadavers, we discovered accessory muscle variants. Dissection of the deep upper back of the female cadaver, we noted a L sided, unilateral, accessory LS muscle slip that casually attached to the serratus posterior superior aponeurosis and tracked with the main body of the LS muscle superiorly. The caudal aspect of the accessory slip inserted perpendicularly onto the broad aponeurotic fibers of the serratus posterior superior muscle around T3. The insertion tracked anterolaterally and superiorly, combining with the muscle belly of the LS around C7-T1 and traveling deep to the right sternocleidomastoid (SCM) to insert on the C1-C4 cervical vertebrae. Following a superior reflection of the R-sided trapezius muscle in the male cadaver, we noted an unilateral accessory muscle band that was attached to the midline spine caudally and tracked with the main body of the LS superiorly. The caudal attachment originated from the T3-T4 spinous process, deep to the rhomboid major muscle and superficial to the posterior serratus superior muscles. The insertion of the accessory runs anteriorly and superiorly, deep to the right SCM, and tracks in a parallel fashion to the main body of the LS. Conclusions: This case series presents two unilateral LS anatomical variants discovered separately during routine cadaveric dissections.
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    It’s not a GIST: A Histopathological Investigation of a Rare Gastric Schwannoma
    (2023) Thai, Stephen; Phan, Jenny; Taft, Carter; Roth, Hannah; Tovar-Vidales, Tara; Crowe, Nicole
    Background: Gastric schwannomas are rare gastrointestinal mesenchymal tumors, accounting for <0.2% of all gastric neoplasms. Gastric schwannomas are benign, arise from the gastrointestinal nerve plexus, and are often misdiagnosed as gastrointestinal stromal tumors (GISTs). Gastric schwannomas are typically incidental findings on conventional imaging studies, surgery, or autopsy. Reported patients are usually asymptomatic. Gastric schwannomas can be differentiated from GIST and other mesenchymal gastrointestinal tumors through the use of immuno-histochemical markers such as S100, Vimentin, and glial fibrillary acidic protein (GFAP). Case Information: During routine dissection of a 78-year-old female, a 1.5 x 1.2 x 1.0 cm tan, firm nodule protruding from the anterior stomach wall was identified. The nodule was located 11 cm from the gastroesophageal junction, 7 cm from the incisura angularis, and 6 cm from the pyloric sphincter. Sectioning revealed white, whorled, and rubbery cut surfaces. No hemorrhage, necrosis, or cystic spaces were grossly appreciated. Subsequently, the tissue underwent routine fixation, processing, paraffin embedding, sectioning, and hematoxylin and eosin (H&E) staining. Using light microscopy, histopathologic findings included a well-circumscribed area containing mostly eosinophilic spindle cells with nuclear palisading, foci of lymphoid infiltration,and a micro-trabecular pattern noted centrally. Additionally, a peripheral lymphoid cuff was present. No mitotic figures were identified. Based on our histopathology findings, we hypothesized the presented nodule to be a gastric schwannoma. This diagnosis was corroborated by immunohistochemistry to demonstrate positive S100b protein expression. Common differential diagnoses include gastrointestinal stromal tumors (GISTs), leiomyomas, and solitary fibrous tumors, all of which lack S100 protein reactivity. Conclusion: This case aims to contribute an additional report about gastric schwannomas to better enhance our collective understanding of this rare lesion.
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    Investigating Associations Between Asthma and Nasal Abnormalities: A Computed Tomography (CT) Approach
    (2023) McCullough, Jason "Drew"; Maddux, Scott D.; Cho, Elizabeth; Ward, Lyndee
    Purpose: Asthma affects over 300 million people worldwide and 3,500 people suffer asthma related deaths each year. Although there is no clear cause of asthma, approximately 90% of asthmatics suffer from cold/exercise induced bronchoconstriction, a symptom triggered by the inhalation of cold and/or dry air. As the nasal passages account for most of the heat and moisture transferred to inspired air during respiration, anatomical variation in nasal morphology may contribute to asthma development. While the existence of nasal anatomical variants is well documented, little is known about the prevalence of such variants among asthmatics. Methods: Accordingly, this study sought to investigate potential associations between asthma and three common nasal anatomical variants: septal deviations, concha bullosa, and paradoxical turbinate. This study analyzed Computer Topography (CT) scans of a diverse, mixed sex sample (n=242) from the New Mexico Decedent Image Database (NMDID). The asthmatic individuals (n= 120) were identified through associated medical records and compared to a control sample of non-asthmatics (n = 122). CT scans were analyzed using Avizo permitting qualitative coding of each anatomical variant for presence and type. Chi-square tests of independence were then used to test for differences in variant prevalence between the asthmatic and control samples. Results: The results of our study show significantly higher prevalence of concha bullosa in asthmatics compared to control individuals (χ2= 5.87, p=0.015), with 70.0% asthmatics exhibiting at least one pneumatized turbinate compared to only 54.9% of control individuals. Conclusions: This result suggests a potential relationship between the presence of conchae bullosa and asthma, possibly due to this variant negatively influencing intranasal air-conditioning capabilities. Future work employing computational fluid dynamics (CFD) analyses may be able to further elucidate the influence concha bullosa have on nasal passage air flow and conditioning. Such work could provide important insights into the role nasal anatomy may play in asthma prevalence and severity. This project was supported by Texas Center for Health Disparities grants RF00241 & RI40241
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    Cranial Bone Ossification Trajectories in a Mouse Model of Osteogenesis Imperfecta
    (2023) Miller, Courtney; Lugo, Laura; Husain, Tooba S.; Organ, Jason; Handler, Emma; Gonzales, Lauren; Menegaz, Rachel A.
    Purpose: Osteogenesis imperfecta (OI) is a genetic disorder that affects the production of type I collagen. Altered collagen production results in delayed or impaired skeletal formation and biomineralization. It also results in the defining characteristics of OI: brittle bones and high rates of fractures. Investigations of skeletal growth in OI have primarily focused on the postcranial skeleton, where interrupted, atypical, and disorganized ossification is seen at long bone growth plates. However, few studies have investigated changes in craniofacial growth in OI and there are currently few early interventions to improve growth trajectories in this region. The current medication prescribed for children with OI to improve skeletal growth, such as bisphosphonates, have major side effects and are not suitable for long-term use. A better understanding of craniofacial development in OI can help with targeting specific developmental stages when new treatments can be administered to provide the best results. The aim of this study is to examine cranial ossification from birth to weaning to determine where and when differences in growth occur in OI. We hypothesize that starting at birth mice with OI will have delayed craniofacial growth due to the poor collagen formation. Methods: To test our hypothesis, we collected cranial bone volumes from micro-CT scans of the homozygous recessive OI murine model (OIM or B6C3Fe a/a-Col1a2oim/oim) and compared them to their wild type (WT) littermates. The OIM model has a COL1A2 mutation that has been found to express a similar skeletal phenotype to the severe form (type III) of OI in humans. Bone volumes were collected from birth (P0) and weaning (P21) from the nasal, frontal, parietal, interparietal, and occipital bones (n=2/genotype/timepoint). Results: At birth, OIM and WT bone volumes were similar. By weaning, bone volume was lower in OIM mice compared to WT mice. Our results demonstrate that OIM mice have reduced rates of bone ossification between birth and weaning, and these differences are most profound in the facial and occipital regions. Additionally, OIM skulls are characterized by low bone volume and potential delays in the closure of cranial sutures and fontanelles. Conclusions: This study suggests that the divergence in cranial ossification rates related to COL1A2 mutations occurs postnatally. Interventions to recover craniofacial bone growth in this experimental model should focus on the critical growth period between birth and weaning. Results from this research have the potential to assist in developing treatments and highlight the importance of early life development of the craniofacial bones in human patients with OI.
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    Osteogenesis Imperfecta: Implications of Using Micro-CT for Visualizing Developmental Variation in the Middle and Inner Ear of OIM Mice
    (2023) Judd, Dallin; Stucki, Brenton; Miller, Courtney; Handler, Emma; Menegaz, Rachel A.; Gonzales, Lauren
    Osteogenesis Imperfecta: Implications of Using Micro-CT for Visualizing Developmental Variation in the Middle and Inner Ear of OIM Mice Dallin R. Judd1, Brenton R. Stucki1, Courtney A. Miller2, Emma Handler3, Rachel A. Menegaz2, Lauren A. Gonzales2 1 Texas College of Osteopathic Medicine, University of North Texas Health Science Center, TX 2 Department of Physiology and Anatomy, University of North Texas Health Science Center, TX 3 Department of Anatomy and Cell Biology, University of Iowa, IA Osteogenesis imperfecta (OI), also known as brittle bone disease, is a genetic bone disorder caused by mutations in the genes COL1A1 and COL1A2, which are responsible for encoding type I collagen. Much is known regarding the effects of the disease on cranial and postcranial elements. However, little is known regarding the pathogenesis and physical manifestations of OI in the ear despite the high rates of hearing loss in patients with OI (~60% of the population is affected). Because ossification or demineralization of structures in the ear may affect the efficacy of certain treatments like cochlear implants, this information deficit limits the treatment options available for OI patients. Thus, the purpose of our research is to visualize and document anatomic variation in the ears of mice bred to have the Type III OI genetic variant in order to better understand the cause of OI-related hearing loss. 3D models of the middle and inner ears were created from micro-CT scans that also employed two new contrast-enhanced methods to visualize the cochlea and middle ear (malleus, incus, and stapes). All CT scanning were done on the UNTHSC campus using the new Small Animal Imaging Facility (SAIF) as part of a previous study. The scan resolution was approximately 20μm. The studied WT and OIM mouse samples include three time points intended to capture a developmental sequence: 0-day-old (WT=20, OIM=29), 7-day-old (WT=23, OIM=23), and 14-day-old mice (WT=22, OIM=18). The visualization software Avizo was then used to digitally segment the bone of the inner ear and middle ear. Gross anatomic differences are currently being documented for each region. Previous work has shown higher levels of ossification and marked bony encroachment of the otic capsule onto the cochlea in the adult OIM mouse model, potentially damaging the soft tissue of the membranous labyrinth. This research uses micro-CT imaging designed to capture a developmental sequence, giving us the potential to elucidate how and when the bony intrusions are impacting surrounding structures. Insight into this anatomical damage may help further clarify OI-related pathology, including the distinction between hearing loss associated with the middle ear (conductive hearing loss) vs. hearing loss associated with the inner ear (sensorineural hearing loss). Furthermore, a preliminary analysis of the developmental sequence should provide insight into when these anatomical changes are first occurring. Upon completion, this research will demonstrate the efficacy of using these new imaging approaches for studying minute structures of the ear and may markedly advance our understanding of the pathogenesis of OI-related hearing loss.