Permeability and Weibel-Palade Bodies of the Blood Vessels in the Human Vocal Fold Mucosa.

OBJECTIVES: Transendothelial exchange and permeability of the capillaries in Reinke space (the superficial layer of the lamina propria) of the vocal fold mucosa affect physiological and pathological conditions of the human vocal fold mucosa. The mechanism of permeability and Weibel-Palade bodies of the blood vessels in the human vocal fold mucosa were investigated using electron microscopy. STUDY DESIGN: Histologic analysis of the human vocal fold. METHODS: Six normal human vocal folds (three adults and three newborns) obtained from autopsy cases and three human vocal folds with Reinke edema from surgical specimens were investigated under transmission electron microscopy. RESULTS: There were three possible capillary wall transport systems related to the permeability of the blood vessels in the vocal fold mucosa: 1) Fenestra transport, plasma exuded from the capillaries into surrounding tissue via the fenestration with or without a diaphragm; 2) vesicular transport (transcellular transport via vesicles), the use of vesicles to ferry fluid and solutes across endothelial cells; and 3) junctional transport (intercellular transport), molecules passed through intercellular gaps between endothelial cells. Weibel-Palade bodies were present in the cytoplasm of endothelial cells both in adults and newborns. They were present in high numbers in the cytoplasm of endothelial cells, with intercellular transport in the vocal folds with Reinke edema. CONCLUSION: There were three types of mechanisms for the permeability of the blood vessels in the human vocal fold mucosa. Some physiologically active substances, such as histamine produced by Weibel-Palade bodies, may adversely influence the permeability of the blood vessels. LEVEL OF EVIDENCE: NA. Laryngoscope, 2588-2592, 2018.

[Value of narrow band imaging endoscopy in detection of early laryngeal squamous cell carcinoma]. / Vyuzití Narrow Band Imaging v dia-gnostice casných karcinomu hrtanu.

BACKGROUND: Narrow band imaging (NBI) is an endoscopic method using filtered wavelengths in detection of microvascular abnormalities associated with preneoplastic and neoplastic changes of the mucosa. The aim of the study is to evaluate the value of NBI endoscopy in the dia-gnosis of laryngeal precancerous and early stages of cancerous lesions and to investigate impact of NBI method in prehistological diagnostics in vivo. MATERIALS AND METHODS: One hundred patients were enrolled in the study and their larynx was investigated using white light HD endoscopy and narrow band imaging between 6/ 2013- 10/ 2014. Indication criteria included chronic laryngitis, hoarseness for more than three weeks or macroscopic laryngeal lesion. Features of mucosal lesions were evaluated by white light endoscopy and afterwards were compared with intra-epithelial papillary capillary loop changes, viewed using NBI endoscopy. Suspicious lesions (leukoplakia, exophytic tumors, recurrent respiratory papillomatosis and/ or malignant type of vascular network by NBI endoscopy) were evaluated by histological analysis, results were compared with prehistological NBI dia-gnosis. RESULTS: Using NBI endoscopy, larger demarcation of pathological mucosal features than in white light visualization were recorded in 32/ 100 (32.0%) lesions, in 4/ 100 (4.0%) cases even new lesions were detected only by NBI endoscopy. 63/ 100 (63.0%) suspected lesions were evaluated histologically -  malign changes (carcinoma in situ or invasive carcinoma) were observed in 25/ 63 (39.7%). Prehistological diagnostics of malignant lesions using NBI endoscopy were in agreement with results of histological examination in 23/ 25 (92.0%) cases. The sensitivity of NBI in detecting malignant lesions was 89.3%, specificity of this method was 94.9%. CONCLUSION: NBI endoscopy is a promising optical technique enabling in vivo differentiation of superficial neoplastic lesions. These results suggest endoscopic NBI may be useful in the early detection of laryngeal cancer and precancerous lesions.

The "postcricoid cushion": observations on the vascular anatomy of the posterior cricoid region.

OBJECTIVE: To describe the cyclical vascular enlargement that occurs in the postcricoid region during the expiratory phase on an infant's cry, and to consider the anatomic, physiologic, and clinical implications of this phenomenon, which we term the "postcricoid cushion." DESIGN: A total of 125 consecutive office fiber-optic laryngoscopic examinations in children and infants were reviewed for engorgement and vascular discoloration of the postcricoid region. Presence of a postcricoid cushion in relation to patient age was reviewed. A comprehensive literature review was also performed. SETTING: Tertiary care pediatric hospital. PATIENTS: Patients from newborns to 17 years old undergoing laryngoscopy for any reason. RESULTS: Sixty-one percent of the videos showed a postcricoid cushion with cyclical enlargement during crying. Eighty-eight percent of children younger than 24 months had presence of a cushion compared with only 38% of children 24 months or older (P < .001). Twenty-five percent of the cushions had violaceous discoloration that resembled a vascular malformation. CONCLUSIONS: Anatomic studies have demonstrated a rich venous plexus in the postcricoid region of the larynx. During the expiratory phase of an infant's cry, there is a cyclical engorgement, occasionally with vascular discoloration, in the postcricoid region at the same level of the venous plexus-the "postcricoid cushion." We propose that during crying, with acute elevation in intrathoracic pressure, there is a filling of the plexus, causing apposition of the postcricoid cushion against the posterior pharyngeal wall, which may serve as a protective barrier to emesis in infants. Our observations relate and differentiate this normal physiologic phenomenon from the rare cases of postcricoid vascular anomalies.

Endoscopic diagnosis of laryngeal cancer and precancerous lesions by narrow band imaging.

OBJECTIVE: To investigate the characteristics of the laryngeal mucosal microvascular network in suspected laryngeal cancer patients, using narrow band imaging, and to evaluate the value of narrow band imaging endoscopy in the early diagnosis of laryngeal precancerous and cancerous lesions. PATIENTS AND METHODS: Eighty-five consecutive patients with suspected precancerous or cancerous laryngeal lesions were enrolled in the study. Endoscopic narrow band imaging findings were classified into five types (I to V) according to the features of the mucosal intraepithelial papillary capillary loops assessed. RESULTS: A total of 104 lesions (45 malignancies and 59 nonmalignancies) was detected under white light and narrow band imaging modes. The sensitivity and specificity of narrow band imaging in detecting malignant lesions were 88.9 and 93.2 per cent, respectively. The intraepithelial papillary capillary loop classification, as determined by narrow band imaging, was closely associated with the laryngeal lesions' histological findings. Type I to IV lesions were considered nonmalignant and type V lesions malignant. For type Va lesions, the sensitivity and specificity of narrow band imaging in detecting severe dysplasia or carcinoma in situ were 100 and 79.5 per cent, respectively. In patients with type Vb and Vc lesions, the sensitivity and specificity of narrow band imaging in detecting invasive carcinoma were 83.8 and 100 per cent, respectively. CONCLUSION: Narrow band imaging is a promising approach enabling in vivo differentiation of nonmalignant from malignant laryngeal lesions by evaluating the morphology of mucosal capillaries. These results suggest endoscopic narrow band imaging may be useful in the early detection of laryngeal cancer and precancerous lesions.

Liquid accumulation in vibrating vocal fold tissue: a simplified model based on a fluid-saturated porous solid theory.

The human vocal fold is treated as a continuous, transversally isotropic, porous solid saturated with liquid. A set of mathematical equations, based on the theory of fluid-saturated porous solids, is developed to formulate the vibration of the vocal fold tissue. As the fluid-saturated porous tissue model degenerates to the continuous elastic tissue model when the relative movement of liquid in the porous tissue is ignored, it can be considered a more general description of vocal fold tissue than the continuous, elastic model. Using the fluid-saturated porous tissue model, the vibration of a bunch of one-dimensional fibers in the vocal fold is analytically solved based on the small-amplitude assumption. It is found that the vibration of the tissue will lead to the accumulation of excess liquid in the midmembranous vocal fold. The degree of liquid accumulation is positively proportional to the vibratory amplitude and frequency. The correspondence between the liquid distribution predicted by the porous tissue theory and the location of vocal nodules observed in clinical practice, provides theoretical evidence for the liquid accumulation hypothesis of vocal nodule formation (Jiang, Ph.D., dissertation, 1991, University of Iowa).

Vocal nodules and edema may be due to vibration-induced rises in capillary pressure.

HYPOTHESIS: Vocal fold vibration may physically raise intravascular pressure to levels high enough to damage capillaries and result in leakage of erythrocytes. This type of injury is commonly seen in benign vocal fold lesions and is not well explained. STUDY DESIGN: Theoretical, retrospective. METHODS: The relationship of intravascular pressure to vibration frequency and amplitude is derived and confirmed with a physical blood vessel model, then applied to published human measurements to estimate human intravascular pressures. RESULTS: Vocal fold intravascular pressure is predicted to have a quadratic dependence on both frequency and amplitude. During speaking, the pressure may rise to over 20 cmH2O, and may reach levels far higher for screaming and singing. Such pressure magnitudes are known to trigger inflammatory cascades and can lead to fluid leakage. They also have the potential for pharmacologic control with beta-agonists. CONCLUSIONS: Intravascular pressure likely rises significantly during vocal fold vibration and may lead to the type of injury seen in benign vocal fold lesions. The results support voice therapy aimed at reducing vibratory amplitude. More vibratory amplitude measurements need to be performed in a wider range of subjects before the full range of human vocal fold vascular pressures can be estimated.

Piloting a novel porcine model for endolaryngeal injury following prolonged intubation.

OBJECTIVES: (1) To develop a practical animal model of endolaryngeal damage secondary to prolonged endotracheal intubation. (2) To demonstrate the contribution of chronic hypoxia to laryngeal injury in the context of this model. METHODS: Four Sus scrofa piglets were anaesthetized and intubated for 24h. Two animals were maintained in a state of constant hypoxia (pO(2)<60 mmHg) while two others were ventilated with 100% oxygen. Prior to sacrifice, fluorescein dye was infused intravenously to highlight areas of hypoperfusion. The larynx and trachea were then harvested for gross and histological examination. RESULTS: All four specimens demonstrated areas of edema, erythema, and ulceration on gross examination. Areas of significant histological inflammation, ulceration, and necrosis involved tube-mucosa contact, in particular, the arytenoids, the interarytenoid area, and the subglottis. CONCLUSIONS: This animal model represents a practical and novel means for the investigation and treatment of laryngeal injury secondary to prolonged endotracheal intubation. Significant injury to the endolarynx was evident after only 24h of intubation and the injury involved similar areas within the larynx as described in human studies. Although clinical experience suggests that chronic hypoxia is a risk factor for endolaryngeal injury, this model did not provide experimental evidence to support this observation, most likely due to the small study size.

Early immunological changes associated with laryngeal transplantation in a major histocompatibility complex-matched pig model.

Laryngeal transplantation is an increasingly viable proposition for patients with irreversible diseases of the larynx. One human transplant has been performed successfully, but many questions remain before routine transplantation can begin. In order to measure the immunological changes in mismatched transplants, it is first necessary to know the immediate combined effects of ischaemia-reperfusion injury (IRI) plus the added insult of major surgery in a fully matched setting. We measured the changes in immunologically active mucosal cells following 3 h of cold ischaemia and 8 h of in situ reperfusion in a major histocompatibility complex (MHC)-matched minipig model (n = 4). Biopsies were prepared for quantitative, multiple-colour immunofluorescence histology. The number of immunologically active cells was significantly altered above (supraglottis) and below (subglottis) the vocal cords following transplantation and reperfusion (P < 0.05, P < 0.001, respectively). However, the direction of the change differed between the two subsites: cell numbers decreased post-transplant in the supraglottis and increased in the subglottis. Despite the statistical evidence for IRI, these changes were less than the large normal inter- and intrapig variation in cell counts. Therefore, the significance of IRI in exacerbating loss of function or rejection of a laryngeal allograft is open to question. Longer-term studies are required.

Anatomical study of meandering and functions of human intralaryngeal artery.

In recent years, partial laryngectomy and partial reconstruction are increasingly intended for conservation of functions of phonation and swallowing. In partial reconstruction, it is important to comprehend morphological characteristics of the blood vessels distributed in the larynx, but there have been only few reports discussing detailed information about them. Previous reports on laryngeal blood vessels have shown that branches of some arteries show remarkable "meandering". In the present study, we devised a method for objectively determining the morphological nature, "meandering" and assessed functions of the arteries. Intralaryngeal arteries were excised from the larynx of cadavers prepared for practice in anatomy, and images of the "meandering" artery were analyzed with NIH Image. The extent of "meandering" was expressed mainly as the ratio of the total length of the blood vessel to the distance between the starting point and the end point of meandering. The results showed that there was a significant difference in the extent of meandering between superior posterior and medial posterior branches of superior laryngeal artery. These arteries, which were distributed in the arytenoid region, were found to be of primary importance in partial laryngectomy and partial reconstruction of the larynx.

Removal of cartilage rings prevents graft stenosis in extended tracheal allotransplantation with omentopexy and immunosuppression: an experimental study.

BACKGROUND: One of the serious problems in longer size tracheal transplantation is severe stenosis of the graft, probably caused by an inadequate blood supply. We have previously reported that removal of some cartilage rings of the graft and omentopexy helps to provide sufficient blood flow to the graft mucosal tissue and results in satisfactory survival and non-significant graft stenosis in extended tracheal autotransplantation. However, it is unclear whether this method can be applied to extended tracheal allotransplantation that requires immunosuppression. In this report, we describe midterm results of extended tracheal allotransplantation with the technique. METHODS: Twenty-four adult mongrel dogs were used. In 18 dogs, a nine-cartilage-ring length of the trachea was allotransplanted when five cartilage rings of the graft were removed, leaving two rings intact at both ends of the graft for simple fixing to the recipient. Two artificial tracheal rings outside the graft and a stent inside the graft were used for maintaining the lumen width. Omentopexy was done for sufficient blood supply to the graft. FK 506 (0.1 mg/kg) was given on each day after the operation in Group A (n = 10), but was not given at all in Group B (n = 8). In Group C (n = 6), a nine-cartilage-ring length of the trachea, without removal of any cartilage ring, was transplanted into the recipient dog and covered with an omental pedicle flap. The same dose of FK 506 as that used in Group A dogs was given to Group C dogs. RESULTS: In Group A, 2 dogs died of graft stenosis within 9 weeks after surgery and 1 died of emaciation without tracheal stenosis. Seven dogs (70%) survived until time of killing. Among the 8 dogs in Group B, 6 died of graft stenosis within 9 weeks after surgery, with 1 dying of pneumonia and only 1 (13%) surviving for >1 year until killing. In Group C, all 6 dogs died of graft stenosis within 6 weeks after surgery. Survival at 16 weeks after surgery was 70% in Group A, 13% in Group B and 0% in Group C (p < 0.01, A vs B and C). No significant graft stenosis was found in 6 dogs and mild stenosis was found in 2 dogs at the time of death or killing in Group A (80%), whereas mild stenosis was found in only 2 dogs in Group B (25%) (p < 0.05). Mucosal blood flow of the graft in Group A was higher than that in Group C and was the same as that in Group B within 4 weeks after surgery; however, it remained unchanged to ultimately be higher than in Group B at 6 and 8 weeks after surgery. CONCLUSIONS: Removal of some cartilage rings, omentopexy and immunosuppression improved blood supply to the graft and resulted in good survival and non-significant tracheal stenosis in extended tracheal allotransplantation.

Distribution of NADPH-diaphorase activity in the feline laryngeal mucosa.

We studied nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase activity in the feline laryngeal mucosa using a histochemical technique in an effort to clarify the role of nitric oxide (NO) in the larynx. Many NADPH-diaphorase-positive nerve fibres were distributed around the blood vessels and the laryngeal glands. The majority of neuronal cells in the intralaryngeal ganglia were NADPH-diaphorase-positive. It is likely that NADPH-diaphorase-positive nerve fibres around the blood vessels and glands in the laryngeal mucosa originate from the intralaryngeal ganglia, and that NO regulates circulation and secretion in the larynx.

Effect of hyperventilation on airway mucosal blood flow in normal subjects.

The purpose of this study was to determine the effect of hyperventilation (40 L/min) with room air (25 degrees C; 70% relative humidity) and frigid air (-10 degrees C; 0% relative humidity) on airway mucosal blood flow (Qaw) in normal subjects (n = 7; 26 to 54 yr of age). Qaw was measured with the dimethyl ether uptake technique, which reflects blood flow in the mucosa of large airways corresponding to a 50-ml anatomic dead space segment extending distally from the trachea. Mean (+/- SE) baseline Qaw during quiet (room air) breathing was 6.6 +/- 0.6 ml/min (range, 3.9 to 10.9). Qaw failed to change significantly during and after eucapnic hyperventilation with room air (thermal stress, 224 cal/min). In contrast, eucapnic hyperventilation with frigid air (thermal stress, 720 cal/min) increased Qaw in every subject, with the peak value occurring either during or over a 30-min period after hyperventilation; by 60 min, Qaw had returned toward baseline. The mean maximal Qaw was 310 +/- 49% of baseline (p < 0.05). Neither type of hyperventilation had an effect on airway resistance. We conclude that in normal subjects, Qaw increases during and/or after eucapnic hyperventilation with frigid air, and that this response is related to the magnitude of the thermal stress rather than to the level of ventilation.

Vascularized fascia as a transferable bed for experimental laryngeal reconstruction.

Laryngeal defects were reconstructed with a combined vascular flap consisting of lateral thoracic fascia used as a transferable vascular bed. A buccal mucosal graft was fixed on this bed as an internal lining. An autogenous cartilage graft, circumferentially wrapped in vascular connective tissue, was used as external support. The first focus of interest of this experimental study was to investigate the necessity of epithelial lining in the repair of a full-thickness laryngeal wall defect. The second focus of interest was to study reconstruction of the posterior glottis by introducing additional supporting material.

Reflex bronchial vasodilation in dogs evoked by injection of a small volume of water into a bronchus.

Injection of water into a lobar bronchus stimulates airway C-fibers and rapidly adapting receptors and evokes airway defense reflexes. To determine whether this stimulus also evokes a reflex increase in bronchial blood flow (Qbr), we injected 1-2 ml of water into a lobar bronchus in anesthetized dogs. Injection decreased arterial pressure but increased Qbr from 9 +/- 1 to 21 +/- 3 ml/min. The increase had a latency of 6-8 s and reached a peak after approximately 20 s; Qbr returned to control after 60-90 s. Airway mucosal blood flow, measured by colored microspheres, increased in proportion to Qbr. In contrast, flow in an adjacent intercostal artery that did not supply the airway decreased slightly. Injection of isosmotic saline had little effect. In 13 of 16 dogs, the water-induced increase in Qbr was abolished by cutting or cooling the cervical vagus nerves and hence was entirely dependent on centrally mediated vagal pathways. When the vagus nerves were intact, about one-third of the vasodilator response remained after pharmacological blockade of muscarinic and adrenergic receptors. We conclude that in dogs the defense response to water in the lower airways includes a large increase in Qbr that is partly due to activation of nonadrenergic noncholinergic autonomic pathways.

Mucosal blood volume and oxygen saturation in the human vocal fold.

With a newly developed spectrophotometric analyzer we were able to measure hemoglobin (Hb) concentration and its oxygen saturation in the human vocal and ventricular folds. Studies were made on 30 subjects including 18 normal controls. In laryngomicrosurgery under general anesthesia, measurements were made with a fiber probe touching the laryngeal mucosa. Results were as follows: In normal mucosa of the vocal fold, the mean value of IHb was 40 and the ISO2 was 55, while in that of the ventricular fold, the mean values were 74 and 56, respectively. Thus, in spite of the influence of general anesthesia, the mucosal blood volume was lower in the vocal fold than in the ventricular fold. The mean value of IHb was 30 in the vocal fold polyps, 122 in the vocal fold nodule, 43 in the polypoid degenerations, 17 in the vocal fold cyst, 62 in the granuloma, 6 in the sulcus vocalis and 19 in the hyperkeratoses. This method is considered useful for objective and quantitative analysis of pathological conditions in the vocal fold.

[Measurement of human laryngeal mucosal blood volume].

To the best of our knowledge little if any information is available concerning human laryngeal mucosal blood volume presumably because the larynx is an anatomical position which renders the measurement of blood flow there difficult. With the advent of a reflectance spectrophotometer, however, studies of tissue blood flow have been facilitated to a great extent. As a result, attempts have been made to determine mucosal blood volume in various organs and tissues including the gastric mucosa. Recently, an ultra-thin fiber probe (1.8 m min diameter) for measurement of tissue blood volume has been developed. Using a laryngeal flexible fiberscope attached with this newly developed probe in the opening for the forceps, an attempt was made to measure laryngeal mucosal blood volume by the method of reflectance spectrophotometry, determining IHb and ISO2 the former of which is a parameter of hemoglobin in the tissue blood vessels and the latter, a parameter of hemoglobin oxygen saturation in the tissue blood vessels. IHb of the vocal folds is significantly low, about half those of the false folds and arytenoid region, whereas ISO2 is significantly higher in the false folds and arytenoid region than in the vocal folds. The hemodynamics in the vocal folds as a high-speed vibrator are specific, unlike in other laryngeal regions. We have plans to determine laryngeal tissue blood volume at more sites so as to investigate the laryngeal tissue distribution of blood volume in greater detail. Furthermore, tissue blood volume in morbid conditions will also be determined for information which will be of value in clinical applications.

Ultrastructural study on the small blood vessels of human vocal cords.

Small blood vessels of human vocal cords were examined by electron microscopy. The endothelial cells contain a large number of filaments. Two kinds of filaments could be differentiated: Short intermediate filaments with a diameter of 10-12 nm, which were localized in the pericaryon, and bundles of thin filaments with a periodicity of 480 nm lying beneath the luminal cellular membrane. The basement membrane of capillaries, arteries, and veins was lamellate. Between the outermost, not fully closed lamellae, myocytes or pericytes could be seen. Both the lamellate basement membranes and the large number of intermediate filaments in the endothelial cells are discussed as stabilizing structures in blood vessels which are exposed to high mechanical forces. The bundles of cross-striated thin filaments may possibly increase the permeability of the vessel wall by their contraction, permitting the well-known fast development of edema in the vocal cords. The importance of Weibel-Palade bodies, which could be disclosed in the endothelial cells in large numbers, is not yet known.

[The microvascularisation of the laryngeal and tracheal mucosa. Introduction to the physiopathology of stenosing lesions (author's transl)]. / Micro-vascularisation de la muqueuse laryngée et trachéale. Introduction à la physiopathologie des lésions sténosantes.

The authors studied the vascular supply of the laryngeal and tracheal mucosa. They based their results on the technique of microangiography. In this study the authors compare the distribution of the small vessels of the mucosa of the cervical trachea and of the larynx--posterior commissure, laryngeal surface of the spiglottis and sub-glottal level. There are analogies between the mucosa of the trachea and that of the sub-glottal level. The region of the posterior commissure has special characteristics. The authors demonstrate the importance of these small vessels in the physiopathology of stenosing lesions (post-tracheotomy or post-intubation).