Growth and development of epiglottis and preepiglottic space of larynx as it acquires vocal tract.

Objectives: The growth and development of the epiglottis and preepiglottic space (PES) of the human larynx as it acquires the vocal tract were investigated. Methods: Three newborns, one infant, four children (2, 7, 8, and 12 years old), and two adult normal larynges were investigated and compared using the whole organ serial section technique. Results: The newborn PES occupied a small area just anterior to the epiglottis. It was composed of immature adipose tissue and areolar tissue. The epiglottis lay on a somewhat horizontal axis and is partially obscured behind the hyoid bone. The hyoid bone overlapped the thyroid cartilage, partially obscuring the superior thyroid notch. The newborn epiglottic cartilage was immature elastic cartilage, and the elastic fiber component was sparse. In the first 8 years of life, as the PES grew, the PES was located not only anterior to but also posterolateral and inferolateral to the epiglottic cartilage and thyroepiglottic ligament. Meanwhile, the epiglottic cartilage matured. Conclusions: In order to develop the vocal tract for speech production, it is reported that the human larynx descends as the child grows in the first 9 years of life. This study showed that the PES, occupying a small area just anterior to the epiglottis, grew and existed astride the epiglottis as the larynx descended and the vocal tract developed. Consequently, its distribution allows the epiglottis to more effectively play the role of retroflection during swallowing in order to prevent aspiration. The human speech faculty likely develops in conjunction with swallowing physiology.

Relationship between Swallowing Pressure and Saliva Residue on Endoscopic Evaluation in Pharyngeal Dysphagia.

OBJECTIVE: In pharyngeal dysphagia, poor pharyngeal contraction and upper esophageal sphincter (UES) dysfunction result in post-swallow saliva residue (SR). This study aimed to clarify the relationship between swallowing pressure and SR in the valleculae and piriform sinuses on flexible endoscopic evaluation of swallowing (FEES). METHODS: Pharyngeal dysphagia patients with Wallenberg syndrome were included. Amounts of post-swallow SR in the valleculae and piriform sinuses were classified into four grades using SR scores based on FEES. The Hyodo score was also calculated to evaluate swallowing function. High-resolution manometric data in the nasopharyngeal, oropharyngeal, hypopharyngeal, oro-hypopharyngeal, and UES zones on swallowing were obtained for comparison with SR and Hyodo scores. RESULTS: Of the 31 recruited, data from 26 patients who successfully underwent FEES and manometry were analyzed. Vallecular SR scores were strongly negatively correlated with a maximum pressure of the oropharynx (r = -0.52, p = 0.006), distal contractile integrals (DCI) of the oropharynx (r = -0.52, p = 0.007), and DCI of the oro-hypopharynx (r = -0.55, p = 0.004). Hyodo scores for parameters 1 and 4 (corresponding to salivary pooling and pharyngeal clearance, respectively) were strongly negatively correlated with a maximum hypopharyngeal pressure (r = -0.57, p = 0.002) and strongly positively correlated with peristaltic velocity (r = 0.53, p = 0.007), respectively. SR scores and Hyodo scores related to SR were not correlated with pressure data of the UES. CONCLUSION: Manometric analysis of our SR scoring method using FEES revealed that a higher amount of SR in the valleculae, but not in the piriform sinuses, is associated with weaker pharyngeal pressure in pharyngeal dysphagia, especially at the oropharyngeal level. LEVEL OF EVIDENCE: 4 Laryngoscope, 2024.

The risk of pocket infection or bloodstream infection following central venous port placement for the patients with Cetuximab therapy.

OBJECTIVE: Cetuximab is a molecular targeted drug that targets epithelial growth factor receptors. The skin toxicity of cetuximab arising from epithelial growth factor inhibition is well known. Some patients with cetuximab therapy decided to make central venous port during the long-term intravenous treatments. Therefore, the author hypothesized that cetuximab administration might increase the risk of central venous port-related infection due to damage to skin barrier function. The main aim of the present study was to investigate the relationship between cetuximab administration and central venous port-related infection. METHODS: A total of 83 patients had a central venous port placed from 2016 through 2021. We analyzed, retrospectively, the relationship between cetuximab therapy and the incidence of central venous port-related infection involving central line-associated bloodstream infection and pocket infection. Additionally, the risk factors of central venous port-related infection were examined in the population undergoing cetuximab therapy. RESULTS: In total populations (83 cases), central line-associated bloodstream infection happened in five patients (6%) and pocket infection happened in six patients (7%) after central venous port placement. In the cetuximab therapy group (45 cases), there were four patients with central line-associated bloodstream infection (9%) and six with pocket infection (13%). The pocket infection happened more frequently in the cetuximab group than the other group with significant differences. Additionally, in the cetuximab group, the patients who had an interval of less than seven days between central venous port placement and cetuximab dosing, or central venous port placement preceded by cetuximab dosing had more pocket infection with significant differences. CONCLUSION: Skin complications after the central venous port placement were related to cetuximab administration and the timing of cetuximab therapy.

Pathogenesis of Reinke's Edema of the Vocal Fold.

OBJECTIVES: The most frequent etiologic factor of Reinke's edema (RE) is considered to be smoking. However, the mechanism for the onset and development of the disease remains unclear. Hypoxia-inducible factor-1α (HIF-1α) is an oxygen-dependent transcriptional activator which plays crucial roles in angiogenesis in hypoxic microenvironments. HIF-1α induces the expression of vascular endothelial growth factor (VEGF) which involves angiogenesis and enhances vascular permeability. This study investigated the roles of HIF-1α in the pathogenesis of RE. METHODS: Surgical specimens of RE from patients who underwent endolaryngeal microsurgery were used. Normal vocal folds were used as a control group. Expression of HIF-1α and VEGF was analyzed by immunohistochemistry. Three-dimensional fine structures of the vessels in RE were investigated using correlative light and electron microscopy (CLEM) technique. RESULTS: HIF-1α and VEGF were broadly expressed in the stromal, inflammatory, and endothelial cells in the lamina propria of the vocal fold of RE. The expression of HIF-1α and VEGF of RE were significantly higher than in the lamina propria of the normal vocal fold mucosa. CLEM showed vascularization and telangiectasia and there were many dilated capillaries with thin endothelium not covered with pericytes indicating the vessels were fragile. CONCLUSION: Transcription factor HIF-1α and induced VEGF likely play roles in the pathogenesis of RE. And increased vascular permeability with fragile vessels in angiogenesis is likely to be an etiology of RE. Transcription factor HIF-1α and induced VEGF are potential therapeutic targets for RE. LEVEL OF EVIDENCE: NA Laryngoscope, 134:1785-1791, 2024.

Glycolytic Metabolism of the Tissue Stem Cells in the Maculae Flavae of the Human Vocal Fold.

OBJECTIVES: Metabolic programs in the stem cells are essential for maintaining homeostasis and protecting against stem cell aging. There is growing evidence that the tissue stem cells reside in the anterior and posterior maculae flavae of the human vocal fold mucosa. Our previous studies observed that the glycolysis of the cell in the human maculae flavae seems to rely more on anaerobic glycolysis for energy supply in comparison with oxidative phosphorylation. However, previous studies showed only the metabolic enzymes of glycolysis and functional morphology of the mitochondria, therefore, it has not yet been determined whether anaerobic glycolysis actually took place. The purpose of this study is to investigate the glycolytic metabolites of the cells in the maculae flavae of the human vocal fold in vitro. METHODS: Four normal human vocal folds were used. After extraction of the anterior maculae flavae, cells in the maculae flavae were cultured and proliferated. Glucose transporter-1 was assessed using immunocytochemistry and metabolites of glycolysis (lactate and NADPH) were measured. RESULTS: The cells in the maculae flavae expressed glucose transporter-1 in the cytoplasm and the cell membranes. In addition, the cultured cells produced lactate (metabolites of anaerobic glycolysis) and NADPH (metabolites of the pentose phosphate pathway). CONCLUSIONS: The cells in the maculae flavae of the human vocal folds were found to undergo anaerobic glycolysis via the pentose phosphate pathway. This suggests that the cells in the maculae flavae of the human vocal fold have a metabolism that favors the maintenance of stemness and undifferentiated states.

Small Cell Neuroendocrine Carcinoma of the Parotid Gland: An Uncommon Example of Incompletely Encapsulated Tumor Including S100 Protein-Positive Clear Cells.

Small cell carcinoma is rare in salivary glands and has recently been termed small cell neuroendocrine carcinoma. We herein describe an uncommon example arising in the parotid gland. The patient was a 75 yearold Japanese male who had swelling in the right parotid area. He underwent a superficial lobectomy and, after a histological diagnosis was made, a total parotidectomy. Histologically, the tumor had a thick hyalinized capsule that was incomplete, beyond which the tumor invaded into the surrounding parotid parenchyma. The tumor consisted of typical small basophilic cells intermingled with bland clear cells, between which a gradual transition was observed both inside and outside the capsule. Small basophilic cells were immunoreactive for chromograninA as well as synaptophysin, while clear cells were positive for S100 protein. The Ki-67 labeling rate reached 30-40% at the high points of small basophilic cells, but clear cells were minimally labelled. The present case was considered a dedifferentiated carcinoma of the parotid gland, possibly with acinic cell carcinoma as a precursor. This tumor could also be considered a "mixed exocrine-endocrine carcinoma," which may explain the histogenesis of neuroendocrine carcinomas in non-endocrine organs that are not included in the diffuse (dispersed) neuroendocrine system, such as the parotid gland.

Case Report: A case of complete response to entrectinib in NTRK fusion gene-positive parotid gland cancer.

Introduction: Expression of the NTRK gene is rare in solid tumors but is highly prevalent in salivary gland secretory carcinomas. Here, we report a case of a complete response to entrectinib in a patient with NTRK fusion gene-positive parotid carcinoma. Case description: The patient was a 44-year-old man who underwent total left parotidectomy and left cervical lymph node dissection for a left parotid tumor at 24 years of age. The histopathological diagnosis was mammary analog secretory carcinoma. Postoperatively, the patient received only radiation therapy. Sixteen years after the surgery, the patient became aware of a mass in the left parotid region. A close examination revealed local recurrence and multiple cervical lymph node metastases. S-1 monotherapy was started as chemotherapy but was discontinued 3 years later because of disease progression. As there was no standard treatment, a comprehensive genomic profiling test using a next-generation sequencer was performed, and the ETV6-NTRK3 fusion gene was identified. Entrectinib, an NTRK inhibitor, was immediately administered at a dose of 600 mg/day. The local recurrence rapidly shrank grossly from the beginning of treatment, and a complete response was observed 6 months later. However, creatinine levels exhibited an increase at week 68 of treatment; consequently, entrectinib dosage was lowered to 400 mg/day, leading to an immediate improvement in creatinine levels. Entrectinib was associated with additional side effects, including dysgeusia, fatigue, dizziness, and weight gain, all of which were also alleviated by the reduction in entrectinib dose. Thirty months after treatment initiation, the patient maintained a complete response and continued to receive entrectinib. Conclusion: The NTRK fusion gene should always be checked in the presence of salivary gland secretory carcinoma.

Prognostic values of systemic inflammation and nutrition-based prognostic indices in oropharyngeal carcinoma.

Objective: Pretreatment systemic inflammation and nutrition-based prognostic indices (SINBPI) have demonstrated significance. This study investigated the prognostic value of pretreatment SINBPI for patients with oropharyngeal cancer and identified unfavorable prognostic markers. Methods: We retrospectively reviewed the data of 124 patients with oropharyngeal squamous cell carcinoma (OPSCC) who received definitive treatment between January 2010 and December 2018. The prognostic utility of the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), prognostic nutritional index, and high-sensitivity modified Glasgow prognostic score (HS-mGPS) was assessed for disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS) using univariate and multivariate analyses. Results: Multivariate analyses revealed that human papillomavirus (HPV) status and HS-mGPS were significantly associated with DFS, DSS, and OS. Patients with a HS-mGPS of 2 had a significantly higher rate of treatment-related deaths than those with a HS-mGPS of 0 or 1. The combination of the HS-mGPS and PLR had more accurate predictive ability in DFS and OS compared with the HS-mGPS alone, and the combination of the HS-mGPS and LMR had more accurate predictive ability in DSS and OS. Conclusion: Our results indicated that the HS-mGPS was a useful prognostic marker for patients with OPSCC, and combined markers consisting of the HS-mGPS and PLR or LMR may provide more accurate prognostic predictions.Level of Evidence: 3.

Vascularity in the macula flava of human vocal fold as a stem cell niche.

OBJECTIVES: There is growing evidence that the maculae flavae of the human vocal fold are a stem cell niche, which is a microenvironment nurturing tissue stem cells. This study investigated the microenvironment, especially vascularity, in the maculae flavae of the human vocal fold. METHODS: Three normal human adult, three normal newborn vocal folds obtained from autopsy cases and three surgical specimens of glottic carcinoma were investigated using light and electron microscopy. For scanning electron microscopy, a chemical digestion method (modified sodium hydroxide maceration method) was used to observe the inner 3-dimensional structure of the macula flava. RESULTS: Capillaries ran around the anterior and posterior maculae flavae in adults and newborns. However, there was no vascularity in the maculae flavae of the vocal fold. The inner 3-dimensional electron microscopic structure of the macula flava showed there were no blood vessels in the maculae flavae of the vocal fold. Glottic carcinoma (squamous cell carcinoma) surrounded and was in contact with the macula flava, however, the carcinoma did not invade the macula flava indicating there was no vascular supply into the macula flava from the surrounding tissue. CONCLUSIONS: There was no vascularity in the anterior and posterior maculae flavae in the human adult and newborn vocal folds. The present study is consistent with the hypothesis that the hypoxic microenvironment in the maculae flavae of the adult and newborn vocal fold as a stem cell niche is likely favorable to maintaining the stemness and undifferentiated states of the tissue stem cells in the stem cell system.

Three-dimensional fine structures of the maculae flavae of the human vocal fold using correlative light and electron microscopy.

Objectives: To analyze various aspects of complex tissue, there is increasing demand to study each sample at different length scales in biology. Correlative light and electron microscopy (CLEM) is the latest technique to correlate two different types of information on the exact same histological area of interest: histology (from light microscopy) and ultrastructure (from electron microscopy). The three-dimensional fine structures of the maculae flavae (MFe) of the human vocal fold were investigated using CLEM. Methods: Five normal human adult vocal folds as specimens embedded in paraffin, sectioned, and mounted on glass slides with/without a chemical digestion method (modified sodium hydroxide maceration method) were investigated. Observations using CLEM were performed. Results: The fine structures of cells and extracellular matrices in the MFe and their peripheral regions were able to be observed on the exact same histological area of interest with the light microscope and field emission-scanning electron microscope. Cobblestone-like polygonal cells, vocal fold stellate cell-like cells, and fibroblast-like spindle cells were intermingled in the MFe of the human vocal fold. The extracellular matrices surrounding each three types of cell in the MFe differed, suggesting the cells were different in functional property. Conclusion: CLEM is a useful technique to observe the three-dimensional fine structures of the human vocal fold mucosa. The results of the present study are consistent with the hypothesis that the cells in the MFe of the human vocal fold have heterogeneity and each three types of cell have different properties.

Glycolysis of Tissue Stem Cells in the Macula Flava of Newborn Vocal Fold.

OBJECTIVES: There is growing evidence that the cells in the maculae flavae are tissue stem cells and the maculae flavae are a stem cell niche of the human vocal fold mucosa. This study investigated the metabolic activity, especially glycolysis, of the tissue stem cells in the maculae flavae of the human newborn vocal fold. METHODS: Three normal human newborn vocal folds obtained from autopsy cases were investigated using immunohistochemistry. RESULTS: Among the three phenotypes of cells (cobblestone-like polygonal cells, vocal fold stellate cell-like cells and fibroblast-like spindle cells) in the newborn maculae flavae, a small number of cobblestone-like polygonal cells strongly expressed glucose transporter-1. All three phenotypes of cells in the newborn maculae flavae expressed glycolytic enzymes (hexokinase II, glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase A). The cells did not express phosphofructokinase-1 (rate-limiting enzyme of regular glucose metabolism pathway) but sparsely express glucose-6-phosphate dehydrogenase (rate-limiting enzyme) indicating the cells relied more on the pentose phosphate pathway. The cells' expression of lactate dehydrogenase A suggests the maculae flavae of the newborn vocal fold is likely to be an anaerobic microenvironment where cells perform anaerobic glycolysis. CONCLUSIONS: The present study is consistent with the hypothesis that the tissue stem cells in the maculae flavae of the newborn vocal fold seem to rely more on anaerobic glycolysis, especially by the pentose phosphate pathway, for energy supply. Already at birth, the metabolism of the tissue stem cells in the maculae flavae of the newborn vocal fold is likely to prevent the formation of toxic reactive oxygen species and is likely favorable to maintaining the stemness and undifferentiated states of the tissue stem cells in the stem cell system.

Dysphagia Precipitated by Cervical Lordosis in the Aged.

A lordotic curve of the cervical spine in the aged is a physiological curvature of the cervical spine. The swallowing disorder precipitated by lordosis of the cervical spine in the aged, the swallowing function and intervention were reported on. An 86-year-old woman complained of swallowing difficulty for a few months. A lordotic curve (physiological curvature) of the cervical spine was observed. In the neutral neck position, the cervical lordotic angle was 29° using the Cobb C2-C7 method. When the lordotic curve of the cervical spine was intentionally straightened, the lordotic angle became 0°, the laryngeal elevation changed from 0.5 times the height of a cervical vertebra to 1.75 times, the laryngeal elevation delay time changed from 0.5 seconds to 0.23, the percent laryngeal elevation changed from 50% to 72% and pharyngeal transit time changed from 0.83 seconds to 0.75. Lordosis of the cervical spine inhibited laryngeal elevation and influenced the swallowing function. In cases in which lordotic curvature of the cervical spine adversely influences the swallowing function in the aged, rehabilitation to manage the lordosis of the cervical spine is useful. For the purpose of effective intervention, not only diagnostic but also therapeutic videofluorographic examination of swallowing is very important.

Laryngeal spaces in the newborn larynx.

OBJECTIVES: Distributions of laryngeal spaces are important in understanding their functional significance. However, laryngeal spaces in the newborn larynx are enigmatic. METHODS: Five normal human newborn larynges were investigated using whole organ serial section technique. RESULTS: The chief newborn laryngeal spaces were the preepiglottic space, the paraglottic space and the cricoid area. They consisted of an areolar tissue area composed of brown adipose tissue (immature adipose tissue) and loose elastic and collagen fibers. The newborn preepiglottic space was immature and occupied a small area anterior to the epiglottis. The epiglottis lied on a somewhat horizontal axis and was partially obscured behind the hyoid bone. The hyoid bone overlapped the thyroid cartilage, partially obscuring the superior thyroid notch. The thyroid cartilage was present close to the hyoid bone and the thyrohyoid membrane ran between the superior surface of the thyroid lamina, and not the anteroinferior, but the posteroinferior surface of the hyoid bone. The preepiglottic space was located anterior, lateral and posterolateral to the thyroepiglottic ligament. However, the preepiglottic space was located anterior to the epiglottic cartilage. As seen in adults, the paraglottic space existed medial to the lamina of each bilateral thyroid cartilage. Each bilateral cricoid area was located along not only the superomedial but also the medial portion of the cricoid arch on both sides. CONCLUSIONS: As the child grows, the preepiglottic space, occupying a small area anterior to the epiglottis, likely grows as the larynx descends and acquires the human adult vocal tract. From the functional histoanatomical point of view, the newborn laryngeal spaces appear to be favored for respiration and maintenance of a protective sphincter for the lower airway over phonation.

Comparative Treatment Outcome in T3N0 Glottic Cancer With and Without Vocal Fold Fixation Receiving Radiation Therapy and Concurrent Low-Dose Intra-Arterial Cisplatin Infusion.

OBJECTIVES: Selective radiotherapy and concomitant intra-arterial cisplatin infusion (m-RADPLAT) with a lower cisplatin dosage have been performed for organ and function preservation in patients with locally advanced squamous cell carcinoma of the larynx (SCC-L), and results showing a lower rate of adverse events have been reported. This study evaluated the treatment outcomes of patients with T3N0 glottic SCC-L with or without vocal fold fixation (VFF) who were treated with m-RADPLAT. METHODS: We retrospectively reviewed the data of 33 patients with T3N0 SCC-L who received m-RADPLAT. RESULTS: The vocal fold in patients with VFF 3 months after completing m-RADPLAT resumed normal movement in 15 patients (83%) and persisted fixation in 3 (17%). The 3-year local control, laryngeal cancer-specific survival, and overall survival rates of patients with or without VFF were 88.9% and 86.7%, 94.1% and 93.3%, and 88.9% and 86.7%, respectively. Additionally, the 3-year freedom from laryngectomy, laryngectomy-free survival, and laryngo-esophageal dysfunction-free survival rates of patients with or without VFF were 94.4% and 86.7%, 88.9% and 73.3%, and 83.3% and 73.3%, respectively. Grade 3 or higher toxicities were observed in all patients: leukopenia in 4 patients (12%), neutropenia in 5 (15%), anemia in 2 (6%), thrombocytopenia in 3 (9%), and mucositis in 2 (6%). CONCLUSIONS: This study demonstrated that m-RADPLAT yielded VFF improvement and a favorable survival while maintaining laryngeal function not only in patients with T3N0 glottic SCC-L without VFF but also in patients with VFF.

Outcomes of long-term nivolumab and subsequent chemotherapy in Japanese patients with head and neck cancer: 2-year follow-up from a multicenter real-world study.

BACKGROUND: We have previously reported the effectiveness and safety of nivolumab in patients with head and neck cancer (HNC) in real-world clinical practice in Japan. Here, we report long-term outcomes from this study in the overall population and subgroups stratified by subsequent chemotherapy. METHODS: In this multicenter, retrospective observational study, Japanese patients with recurrent or metastatic (R/M) HNC receiving nivolumab were followed up for 2 years. Effectiveness endpoints included overall survival (OS), OS rate, progression-free survival (PFS), and PFS rate. Safety endpoints included the incidence of immune-related adverse events (irAEs). RESULTS: Overall, 256 patients received a median of 6.0 doses (range: 1-52) of nivolumab over a median duration of 72.5 days (range: 1-736). Median OS was 9.5 months [95% confidence interval (CI) 8.2-12.0] and median PFS was 2.1 months (95% CI 1.8-2.7). A significant difference between 2-year survivors (n = 62) and non-2-year survivors was observed by median age (P = 0.0227) and ECOG PS (P = 0.0001). Of 95 patients who received subsequent chemotherapy, 54.7% received paclitaxel ± cetuximab. The median OS and PFS from the start of paclitaxel ± cetuximab were 6.9 months (95% CI 5.9-11.9) and 3.5 months (95% CI 2.3-5.5), respectively. IrAEs were reported in 17.2% of patients. Endocrine (7.0%) and lung (4.3%) disorders were the most common irAEs; kidney disorder (n = 1) was newly identified in this follow-up analysis. CONCLUSIONS: Results demonstrated the long-term effectiveness of nivolumab and potential effectiveness of subsequent chemotherapy in patients with R/M HNC in the real-world setting. Safety was consistent with that over the 1-year follow-up.

Metabolic Roles of Colony-Forming Tissue Stem Cells in the Maculae Flavae of Newborn Vocal Fold In Vivo.

OBJECTIVES: Tissue stem cells in the maculae flavae (a stem cell niche) of the human vocal fold form colonies in vivo like stem cells in vitro. However, the roles of colony-forming aggregated cells in the maculae flavae in vivo have not yet been determined. This study investigated the glycolysis, of the colony-forming aggregated cells in the maculae flavae of the human newborn vocal fold in vivo. METHODS: Three normal newborn vocal folds were investigated under light microscopy with immunohistochemistry and transmission electron microscopy. RESULTS: Colony-forming aggregated cells in the newborn maculae flavae strongly expressed glucose transporter-1 and glycolytic enzymes (hexokinase II, glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase A). The colony-forming aggregated cells did not express phosphofructokinase-1 (rate-limiting enzyme of regular glucose metabolism pathway) but expressed glucose-6-phosphate dehydrogenase (rate-limiting enzyme) indicating the cells relied more on the pentose phosphate pathway. The colony-forming aggregated cells' strong expression of lactate dehydrogenase A indicated that they rely more on anaerobic glycolysis in an anaerobic microenvironment. Mitochondrial cristae of the colony-forming aggregated cells in the newborn maculae flavae were sparse. Consequently, the microstructural features of the mitochondria suggested that their metabolic activity and oxidative phosphorylation were low. CONCLUSIONS: The colony-forming aggregated cells in the maculae flavae of the newborn vocal fold seemed to rely more on anaerobic glycolysis using the pentose phosphate pathway for energy supply in vivo. Microstructural features of the mitochondria and the glycolytic enzyme expression of the colony-forming aggregated cells suggested that the oxidative phosphorylation activity was low. Already at birth, in the anaerobic microenvironment of the macular flavae in vivo, there is likely a complex cross-talk regarding metabolism between the colony-forming aggregated cells along the adhesion machinery and chemical signaling pathways which reduces toxic oxygen species and is favorable to maintaining the stemness and undifferentiated states of the tissue stem cells.

Role of colony-forming tissue stem cells in the macula flava of the human vocal fold in vivo.

OBJECTIVES: Our previous investigations showed that tissue stem cells in the maculae flavae (a stem cell niche) form colonies in vivo like stem cells in vitro. However, the roles of colony-forming cells in the maculae flavae in vivo have not yet been determined.This study investigated the metabolism of the colony-forming tissue stem cells in the maculae flavae of the human adult vocal fold. STUDY DESIGN: Histologic analysis of the human vocal folds. METHODS: Three normal human adult vocal folds were investigated under transmission electron microscopy and light microscopy including immunohistochemistry. RESULTS: Mitochondrial cristae of the colony-forming cells in the maculae flavae were sparse. Hence, the microstructural features of the mitochondria suggested that their metabolic activity and oxidative phosphorylation were low. Colony-forming cells strongly expressed glucose transporter-1 and glycolytic enzymes (hexokinase II, glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase A). The colony-forming cells did not express phosphofructokinase-1 but did express glucose-6-phosphate dehydrogenase indicating the cells relied more on the pentose phosphate pathway. Since the colony-forming cells expressed lactate dehydrogenase A, cells seemed to rely more on anaerobic glycolysis in an anaerobic microenvironment. CONCLUSIONS: The present study is consistent with the hypothesis that the colony-forming tissue stem cells in the maculae flavae of the human adult vocal fold seemed to rely more on anaerobic glycolysis using the pentose phosphate pathway for energy supply in vivo. Microstructural features of the mitochondria and expressed glycolytic enzymes of the colony-forming cells in the maculae flavae suggested that the oxidative phosphorylation activity was low.In an anaerobic microenvironment in vivo, there is likely a complex cross-talk regarding the metabolism between the colony-forming aggregated cells along the adhesion machinery and chemical signaling pathways, which reduces toxic oxygen species and is favorable to maintaining the stemness and undifferentiated states of the tissue stem cells. LEVEL OF EVIDENCE: NA.

Effectiveness of nivolumab affected by prior cetuximab use and neck dissection in Japanese patients with recurrent or metastatic head and neck cancer: results from a retrospective observational study in a real-world setting.

BACKGROUND: To examine the effect of prior use of cetuximab and neck dissection on the effectiveness of nivolumab, we conducted a large-scale subgroup analysis in Japanese patients with recurrent/metastatic head and neck cancer. METHODS: Data on the effectiveness of nivolumab were extracted from patient medical records. All patients were analyzed for effectiveness by prior cetuximab use. In the analyses for prior neck dissection, only patients with locally advanced disease were included. RESULTS: Of 256 patients analyzed, 155 had received prior cetuximab. Nineteen of 50 patients with local recurrence underwent neck dissection. The objective response rate was 14.7 vs 17.2% (p = 0.6116), median progression-free survival was 2.0 vs 3.1 months (p = 0.0261), and median overall survival was 8.4 vs 12 months (p = 0.0548) with vs without prior cetuximab use, respectively. The objective response rate was 23.1 vs 25.9% (p = 0.8455), median progression-free survival was 1.8 vs 3.0 months (p = 0.6650), and median overall survival was 9.1 vs 9.9 months (p = 0.5289) with vs without neck dissection, respectively. CONCLUSIONS: These findings support the use of nivolumab for patients with recurrent/metastatic head and neck cancer regardless of prior cetuximab use or neck dissection history. TRIAL REGISTRATION NUMBER: UMIN-CTR (UMIN000032600), Clinicaltrials.gov (NCT03569436).

Glycolytic activity of the tissue stem cells in the macula flava of the human vocal fold.

OBJECTIVES: In our previous studies, the features of the mitochondria of tissue stem cells in the maculae flavae of the human vocal fold suggested that their metabolic activity and oxidative phosphorylation was low. This study investigated the metabolic activity, especially glycolysis of the tissue stem cells in the maculae flavae of the human adult vocal fold. STUDY DESIGN: Histologic analysis of the human vocal folds. METHODS: Three normal human adult vocal folds obtained from autopsy cases were investigated using immunohistochemistry. RESULTS: Among the three phenotypes of cells in the human adult maculae flavae, the vocal fold stellate cell-like cells strongly expressed glucose transporter-1. Three phenotypes of cells in the human adult maculae flavae expressed glycolytic enzymes (hexokinase II, glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase A) indicating the tissue stem cells in the maculae flavae relied more on glycolysis. The cells did not express phosphofructokinase-1 but did express glucose-6-phosphate dehydrogenase indicating the cells relied more on the pentose phosphate pathway. The cells expressed lactate dehydrogenase A indicating the maculae flavae of the human adult vocal fold was likely to be an anaerobic microenvironment. CONCLUSIONS: The present study is consistent with the hypothesis that the tissue stem cells in the maculae flavae of the human vocal fold seem to rely more on anaerobic glycolysis, especially by the pentose phosphate pathway, for energy supply. The metabolism of the tissue stem cells in the maculae flavae of the human adult vocal fold is likely to prevent toxic reaction oxygen species and be favorable to maintaining the stemness and undifferentiated states of the tissue stem cells in the stem cells system. LEVEL OF EVIDENCE: NA.