A systematic review of the perspectives of botulinum toxin use on the quality of life of neurological patients with drooling.

OBJECTIVE: To investigate the effectiveness of botulinum toxin in the salivary glands of patients with neurological impairment and drooling and its impact on the quality of life. MATERIALS AND METHODS: This systematic review was registered with the International Prospective Register of Systematic Reviews (CRD 42,023,435,242) and conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses. An electronic search was performed in the PubMed/MEDLINE, Embase, Scopus, Cochrane Library, and clinical trial databases until August 2023, no language restriction. Cohort studies and randomized clinical trials of patients diagnosed with drooling and neurological impairment who used botulinum toxin on the salivary gland were included, which evaluated subjective quality of life parameters. The risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist and Risk of Bias 2 tools. The certainty of the evidence was analyzed using the Grading of Recommendations Assessment, Development, and Evaluation approach. RESULTS: Eight studies involving 317 patients were included. All studies, through subjective parameters, suggested the effectiveness of botulinum toxin in reducing drooling, resulting in an improvement in the quality of life. Three studies demonstrated improvements in swallowing and four in cases of respiratory diseases. Two clinical trials had a high risk of bias, whereas one had low risk. The five cohort studies that were evaluated had a high risk of bias. The certainty of the evidence was considered low. CONCLUSIONS: Based on the patient/caregivers' perception of improvement in drooling, dysphagia, and respiratory symptoms, it can be inferred that botulinum toxin application reduces subjective drooling in neurologically compromised patients. Its impact contributes to the general well-being and quality of life. CLINICAL RELEVANCE: Injection of botulinum toxin into the salivary glands can be considered an alternative technique to surgical or medicinal approaches in reducing drooling. It is effective, less invasive and without significant side effects. It promotes a positive impact on the well-being and quality of life of neurological patients.

Effectiveness of atropine in managing sialorrhea: A systematic review and meta-analysis.

OBJECTIVES: To describe the efficacy of atropine in controlling salivary flow in patients with sialorrhea or drooling. MATERIALS AND METHODS: We included randomized controlled studies, quasi-randomized trials, case reports, clinical trials, systematic reviews, and meta-analyses assessing the use of atropine in patients with sialorrhea or drooling. The endpoints were reduction in salivary flow rate, amount of saliva secreted, reduction in clinical symptoms of sialorrhea, death rattle intensity, or reduction in drooling intensity as measured by an objective scale such as the drooling intensity scale. RESULTS: A total of 56 studies with 2,378 patients were included in the systematic review. The underlying disease states included brain injury, amyotrophic lateral sclerosis, cerebral palsy, clozapine- and perphenazine-induced sialorrhea, Parkinson's disease, and terminal illness. The routes of atropine administration included sublingual, intravenous, subcutaneous, oral tablet or solution, and direct injection of atropine into parotid glands or at the base of the tongue. The generalized estimated equation regression models showed that sublingual administration is superior to oral and subcutaneous routes. CONCLUSION: Atropine is efficacious in managing sialorrhea in most disease states. Sublingual administration of atropine is superior to other routes of administration in reducing salivary flow in patients with sialorrhea.

Parotid hypersalivation after inferior salivatory nucleus glutamate/NMDA receptor excitation in the rat.

Although salivation is essential during eating behavior, little is known about the brainstem centers that directly control the salivary glands. With regard to the inferior salivatory nucleus (ISN), the site of origin of the parasympathetic preganglionic cell bodies that innervate the parotid glands, previous anatomical studies have located it within the rostrodorsal medullary reticular formation. However, to date there is no functional data that shows the secretory nature of the somas grouped in this region. To activate only the somas and rule out the activation of the efferent fibers from and the afferent fibers to the ISN, in exp. 1, NMDA neurotoxin was administered to the rostrodorsal medullary region and the secretion of saliva was recorded during the following hour. Results showed an increased secretion of parotid saliva but a total absence of submandibular-sublingual secretion. In exp. 2, results showed that the hypersecretion of parotid saliva after NMDA microinjection was completely blocked by the administration of atropine (a cholinergic blocker) but not after administration of dihydroergotamine plus propranolol (α and ß-adrenergic blockers, respectively). These findings suggest that the somata of the rostrodorsal medulla are secretory in nature, controlling parotid secretion via a cholinergic pathway. The data thus functionally supports the idea that these cells constitute the ISN.

The Use of Ipratropium Bromide for the Treatment of Pediatric Sialorrhea: A Retrospective Clinical Case Series.

OBJECTIVE: This retrospective review documents the experience of ipratropium bromide use among pediatric patients with sialorrhea at our multidisciplinary sialorrhea clinic at Children's Hospital at London Health Sciences Centre (LHSC). METHODS: A retrospective chart review of patients diagnosed with sialorrhea at our multidisciplinary clinic between January 2015 and June 2021 was completed. Data on patient demographics, comorbidities, clinical presentation, previous interventions, quality of life, and medication adverse side effects was collected. Drooling Frequency and Severity Scale (DFSS) scores were reviewed to compare sialorrhea management pre- and post-treatment with topical 0.03% ipratropium bromide nasal solution. A descriptive analysis and Wilcoxon signed rank tests were conducted to compare pre- versus post-treatment DFSS scores. RESULTS: A total of 12 patients presented for follow-up and were included in the final analysis. At the pre-treatment visit, the median DFSS score was 4 for frequency and 5 for severity. Post-treatment, median DFSS score was 3 for frequency and 4.5 for severity, (P = .020 and .129, respectively). Minimal adverse effects were encountered. CONCLUSIONS: Ipratropium bromide provided a statistically significant benefit for drooling frequency in the patients studied and may present an additional topical medical option for pediatric sialorrhea with limited adverse effects.

Clinical pharmacokinetics of atropine oral gel formulation in healthy volunteers.

Sialorrhea or drooling is a common problem in children and adults with neurodevelopmental disorders. It can negatively impact the quality of life due to its physical and psychological manifestations. Providers commonly prescribe atropine eye drops for topical administration to the oral mucosa, as an off-label treatment to manage sialorrhea. However, the off-label use of atropine eye drops can be associated with medication and dosing errors and systemic side effects. To address these limitations of treatment, we developed a mucoadhesive topical oral gel formulation of atropine as an alternative route to off-label administration of atropine eye drops. In this clinical pharmacokinetic (PK) study, we evaluated the safety and PK of atropine gel (0.01% w/w) formulation after single-dose administration to the oral mucosa in 10 healthy volunteers. The PK data showed that after topical administration to the oral mucosa, atropine followed a two-compartment PK profile. The maximum plasma concentration and area under the curve extrapolated to infinite time were 0.14 ng/mL and 0.74 h·ng·mL-1 , respectively. The absorption rate constant calculated by the compartmental analysis was 0.4 h-1 . Safety parameters, such as heart rate, blood pressure, and oxygen saturation, did not significantly change before and after administration of the gel formulation, and no adverse events were observed in all participants who received atropine gel. These data indicate that atropine gel formulation has a satisfactory PK profile, is well-tolerated at the dose studied, and can be further considered for clinical development as a drug product to treat sialorrhea.

The state of the art in therapeutic administration of botulinum toxin in children with cerebral palsy: an integrative review.

OBJECTIVE: To describe the current state of the art in the therapeutic administration of botulinum toxin with indications, efficacy, and safety profile for children and adolescents with cerebral palsy. DATA SOURCE: An integrative review was conducted. The MEDLINE/PubMed database was searched twice within the last decade using distinct terms, and only studies written in the English language were included. The study population was limited to those aged 0-18 years. Articles that were duplicates or lacked sufficient methodology information were excluded. DATA SYNTHESIS: We found 256 articles, of which 105 were included. Among the included studies, most were conducted in developed countries. Botulinum toxin demonstrated good safety and efficacy in reducing spasticity, particularly when administered by a multidisciplinary rehabilitation team. It is primarily utilized to improve gait and upper limb function, facilitate hygiene care, reduce pain, prevent musculoskeletal deformities, and even decrease sialorrhea in patients without a functional prognosis for walking. CONCLUSIONS: The administration of botulinum toxin is safe and efficacious, especially when combined with a multi-professional rehabilitation team approach, which increases the probability of functional improvement. It can also be beneficial for patients with significant functional impairments to help with daily care tasks, such as hygiene, dressing, and reducing sialorrhea. Pediatricians must be familiar with this treatment and its indications to attend to and refer patients promptly when necessary, and to exploit their neuroplasticity. Further research on this topic is required in developing countries.

Localization of the Submandibular Glands Using High-Frequency Ultrasound.

BACKGROUND: Injecting botulinum toxin (BTX) into the submandibular glands (SMGs) can treat drooling symptoms in neurological diseases and improve the aesthetics of SMG hypertrophy and ptotic SMGs. OBJECTIVES: This study aimed to define the size and position of the SMGs by high-frequency ultrasound, and to perform statistical analysis to improve the safety and accuracy of BTX injection therapy. METHODS: Neck ultrasonography with high-frequency ultrasound was performed on 214 volunteers. The length, height, and thickness of the SMGs, and the distance between the SMGs and the midline, the anterior border of the sternocleidomastoid, the mandible, and the surface were measured. RESULTS: The SMGs were almond-shaped with a mean [standard deviation] length of 33.7 [4.7] mm, a thickness of 13.3 [2.9] mm, and a height of 27.6 [6.0] mm. The length and height were significantly different between underage and youth groups. The size of the SMGs did not show any notable differences with increasing BMI; however, their depth, and the distance from the mandible, midline, and anterior border of the sternocleidomastoid increased. No significant differences were observed between the affected and healthy sides in patients with microtia, hemifacial microsomia, or cleft lip and palate. CONCLUSIONS: Ultrasound provides more comprehensive information regarding the size and position of the SMGs, which can serve as a reference in BTX therapy and in the diagnosis of SMG diseases involving size alterations.

Botulinum toxin type a blocks aquaporin 5 trafficking by decreasing synaptosomal-associated protein 23 in submandibular acinar cells.

The trafficking of aquaporin 5 (AQP5) is critical for salivary secretion. Synaptosomal-associated protein 23 (SNAP23) is an important regulator in the process of membrane fusion. However, the role of SNAP23 on AQP5 trafficking has not been explored. Botulinum toxin type A (BoNT/A) is a bacterial toxin that effectively treats sialorrhea. We previously reported that BoNT/A induced AQP5 redistribution in cultured acinar cells, but the mechanism remained unclear. In this study, SNAP23 was predominantly localized to the plasma membrane of acinar cells in the rat submandibular gland (SMG) and colocalized with AQP5 at the apical membrane of acinar cells. In stable GFP-AQP5-transfected SMG-C6 cells, the acetylcholine receptor agonist carbachol (CCh) induced trafficking of AQP5 from intracellular vesicles to the apical membrane. Furthermore, SNAP23 knockdown by siRNA significantly inhibited CCh-induced AQP5 trafficking, whereas this inhibitory effect was reversed by SNAP23 re-expression, indicating that SNAP23 was essential in AQP5 trafficking. More importantly, BoNT/A inhibited salivary secretion from SMGs, and the underlying mechanism involved that BoNT/A blocked CCh-triggered AQP5 trafficking by decreasing SNAP23 in acinar cells. Taken together, these results identified a crucial role for SNAP23 in AQP5 trafficking and provided new insights into the mechanism of BoNT/A in treating sialorrhea and thereby a theoretical basis for clinical applications.

Use of botox for sialorrhea and dysphagia in the neonatal population.

INTRODUCTION: Botox is frequently used for sialorrhea in patients with compromised airways and those with etiologies causing difficulty with secretion management (i.e. strokes, neurologic disorders, etc.). There are no published studies regarding the use of botulinum toxin (BoNT) in the neonate population. We aim to discuss our experience and safety of BoNT use in the neonate population in regards to alleviating secretion management and airway protection. METHODS: Retrospective review of neonates admitted to the neonatal intensive care unit (NICU) ≤12 months of age who received BoNT injection to submandibular (SMG) and parotid (PG) glands for sialorrhea/dysphagia. BoNT was administered under ultrasound (u/s) guidance by interventional radiology. RESULTS: 6 children were examined. 2 (33 %) were male. Avg NICU stay was 87.5 ± 33.1 days. 2 underwent surgical airway intervention prior to injection. Mean age at initial BoNT was 1.5 ± 0.7 months. Avg weight at injection was 4 ± 1.1 kg. Each PG and SMG were injected in 5/6 cases. Bilateral SMG were unidentified on u/s in 1 case and thus not injected. Dose range injected per gland was 5-15u. 100 % required tube feeds, 50 % with tubes distal to stomach (NJT/NDT). 83 % were completely NPO prior to injection and there was no noted clinical improvement in oral skills post injection. All had noted desats/apneas prior to injection and 83 % had reported decreased events post injection. 50 % had reported decrease O2 requirements and frequent suctioning 2wks after injection, however 2 (33 %) required surgical airway intervention after injection (trach, SGP/MDO). 4/6 (67 %) trialed medical therapy, anticholinergics being the most common. 50 % underwent 2nd injection (age = 6.5 ± 0.3 months) avg. 4.7 ± 0.7mo after 1st injection, and the same 3pts underwent 3rd injection (age = 12.5 ± 2.4 months) avg. 6.1 ± 2.5mo after 2nd injection. 1 pt. had a total 6 injections. There were no injection related complications. CONCLUSION: BoNT injection is a safe, non-invasive alterative for management of sialorrhea in neonates. Further extensive study needs to be performed to identify the optimal dose per gland in this population.

Saliva Collection Methods Among Children and Adolescents: A Scoping Review.

OBJECTIVE: Saliva can be used for screening and diagnostic purposes. Although multiple saliva collection methods are available, their use in children can be limited due to lack of cooperation, developmental stage, and age. The aim of this scoping review was to comprehensively appraise the different methods of saliva collection among both children and adolescents by assessing the available scientific literature. METHODS: A literature search was performed using the databases PubMed, Embase, and Web of Science. Eligible studies on saliva collection methods among children and adolescents were included for this review. RESULTS: The literature search identified 249 eligible articles, of which 205 had a cross-sectional study design. Four distinct saliva collection methods have surfaced: the drooling method, the absorption method, the spitting method, and the suction method. Among infants or children under the age of 6 years, the suction and absorption methods were most preferred. The drooling and spitting methods were only applicable among children above the age of 3 years. When children were not willing to cooperate, the absorption method was most feasible. In adolescents and older children, no specific method was found to be preferred over another method. CONCLUSION: Overall, saliva collection is well tolerated by children and adolescents, with the absorption and suction methods being preferred with young and uncooperative children.

Self-reported oral moistening disorders in obstructive sleep apnoea: A scoping review.

BACKGROUND: Obstructive sleep apnoea (OSA) is a highly prevalent problem with significant consequences. Continuous positive airway pressure (CPAP) and oral mandibular advancement device (MAD) are considered the standard treatments for OSA. Patients may experience self-reported oral moistening disorders (OMDs) (i.e. xerostomia or drooling) at the beginning, throughout and after treatment. This affects oral health, quality of life and treatment effectiveness. The exact nature of the associations between OSA and self-reported OMD is still unknown. We aimed to provide an overview of the associations between self-reported OMD on the one hand and OSA and its treatment (namely CPAP and MAD) on the other hand. In addition, we sought to determine whether OMD affects treatment adherence. MATERIALS AND METHODS: A literature search in PubMed was performed up to 27 September 2022. Two researchers independently assessed studies for eligibility. RESULTS: In total, 48 studies were included. Thirteen papers investigated the association between OSA and self-reported OMD. They all suggested an association between OSA and xerostomia but not between OSA and drooling. The association between CPAP and OMD was addressed in 20 articles. The majority of studies have indicated xerostomia as a CPAP side effect; however, some have observed that xerostomia diminishes with CPAP therapy. In 15 papers, the association between MAD and OMD was investigated. In most publications, both xerostomia and drooling have been described as common side effects of MADs. These side effects are often mild and transient, and they improve as patients continue to use their appliance. Most studies found that these OMDs do not cause or are not a strong predictor of non-compliance. CONCLUSION: Xerostomia is a common side effect of CPAP and MAD, as well as a significant symptom of OSA. It may be regarded as one of the indicators of sleep apnoea. Moreover, MAD therapy can be associated with OMD. However, it seems that OMD may be mitigated by being adherent to the therapy.

Comparing botulinum toxin and 4-duct ligation for Sialorrhea in children - A systematic review.

INTRODUCTION: Sialorrhea or drooling can result in physical and psychosocial complications, such as aspiration and social isolation. Treatment options include botulinum toxin into the salivary glands and 4-duct ligation (i.e., simultaneous ligation of the bilateral parotid and submandibular ducts). This systematic review aimed to compare the efficacy and complication rates of botulinum toxin and 4-duct ligation for the treatment of drooling in children. METHODS: Following PRISMA guidelines, PubMed, Embase, Web of Science, and Cochrane Library were searched from inception through June 17, 2021 for studies examining the efficacy of botulinum toxin or 4-duct ligation for drooling in children. Data were summarized by pooled counts, percentages, and means. Complication rates were compared by a chi-squared test. RESULTS: A total of 22 studies (n = 606) examining botulinum toxin and 5 studies (n = 124) examining 4-duct ligation were included. From 12 botulinum toxin studies (n = 211), mean drooling frequency and severity scores was 7.5 at baseline. Mean difference from baseline was -2.6 (n = 92) at 4 weeks follow-up, -2.1 at 8 weeks (n = 41), -2.1 at 12 weeks (n = 56), and - 2.1 at 16 weeks (n = 58). From 4 4-duct ligation studies (n = 103), mean baseline drooling frequency and severity score was 8.4. Mean difference was -3.7 at mean follow-up of 35.6 months (n = 103). Eighteen botulinum studies (n = 343) recorded 53 (15.5 %) complications, including thickened saliva (n = 9), dysphagia (n = 4), and cheek abscesses (n = 4). Four 4-duct ligation studies (n = 108) recorded 25 (23.1 %) complications, including parotid gland swelling (n = 4), aspiration pneumonia (n = 3), and oxygen desaturation (n = 3). There was no statistically significant difference in complication rates between botulinum toxin and four-duct ligation (p = 0.065). CONCLUSION: Botulinum toxin injection and 4-duct ligation are both effective in improving sialorrhea in children and have comparable complication rates.

Pulmonary and Clinical Outcomes After Bilateral Submandibular Gland Excision and Parotid Duct Ligation for Refractory Sialorrhea.

Importance: Refractory sialorrhea in children can result in pulmonary aspiration and irreversible lung damage. Despite many studies devoted to the surgical treatment of sialorrhea, there is a paucity of objective outcome measures after surgery, especially with regard to pulmonary health. Objectives: To assess whether bilateral submandibular gland excision and bilateral parotid duct ligation ("DROOL" procedure) is associated with reduced pulmonary inflammation in bronchoalveolar lavage (BAL) samples after surgery and to assess patient factors associated with improvement after surgery. Design, Setting, and Participants: This retrospective case series included all 112 patients undergoing the DROOL procedure at a single tertiary care pediatric children's hospital from January 1, 2012, to December 31, 2021. Statistical analysis was performed from March 30 to June 10, 2023, and August 20 to September 23, 2023. Exposure: DROOL procedure for refractory sialorrhea. Main Outcomes and Measures: Degree of pulmonary inflammation (neutrophil percentage) according to BAL cytologic findings and overall bronchoscopy findings up to 12 months before and after the DROOL procedure. Secondary outcomes included number of annual hospitalizations, caregiver report of function before and after the procedure, and need for revision procedures and/or additional operations for secretion management. Results: A total of 112 patients (median age, 3.4 years [IQR, 2.0-7.1 years]; 65 boys [58.0%]) underwent DROOL procedures and had both preoperative and postoperative BAL samples during the study period. Patients demonstrated objective improvement in pulmonary inflammation after surgery, with the median polymorphonuclear neutrophil percentage decreasing from 65.0% (IQR, 14.0%-86.0%) before the surgery to 32.5% (IQR, 3.0%-76.5%) after the surgery (median difference in percentage points, -9.0 [95% CI, -20.0 to 0.0]). Prior to the DROOL procedure, 34 patients (30.4%; 95% CI, 21.8%-38.9%) were hospitalized 2 or more times annually for respiratory illness, which decreased to 10.1% (11 of 109; 95% CI, 4.4%-15.7%) after surgery (3 patients did not have hospitalization data available following surgery). Most caretakers (73 [65.2%]) reported improved secretion management after the procedure. Conclusions and Relevance: This study suggests that patients with impaired secretion management who underwent a DROOL procedure demonstrated improvement in pulmonary inflammation and a reduction in hospitalizations after surgery. Caretakers were also likely to report subjective improvement in secretion management and quality of life. Additional research is necessary to guide optimal timing and patient selection for this procedure.

Comparing the evidence for botulinum neurotoxin injections in paediatric anterior drooling: a scoping review.

Paediatric anterior drooling has a major impact on the daily lives of children and caregivers. Intraglandular botulinum neurotoxin type-A (BoNT-A) injections are considered an effective treatment to diminish drooling. However, there is no international consensus on which major salivary glands should be injected to obtain optimal treatment effect while minimizing the risk of side effects. This scoping review aimed to explore the evidence for submandibular BoNT-A injections and concurrent submandibular and parotid (i.e. four-gland) injections, respectively, and assess whether outcomes could be compared across studies to improve decision making regarding the optimal initial BoNT-A treatment approach for paediatric anterior drooling. PubMed, Embase, and Web of Science were searched to identify relevant studies (until October 1, 2023) on submandibular or four-gland BoNT-A injections for the treatment of anterior drooling in children with neurodevelopmental disabilities. Similarities and differences in treatment, patient, outcome, and follow-up characteristics were assessed. Twenty-eight papers were identified; 7 reporting on submandibular injections and 21 on four-gland injections. No major differences in treatment procedures or timing of follow-up were found. However, patient characteristics were poorly reported, there was great variety in outcome measurement, and the assessment of side effects was not clearly described.   Conclusion: This review highlights heterogeneity in outcome measures and patient population descriptors among studies on paediatric BoNT-A injections, limiting the ability to compare treatment effectiveness between submandibular and four-gland injections. These findings emphasize the need for more extensive and uniform reporting of patient characteristics and the implementation of a core outcome measurement set to allow for comparison of results between studies and facilitate the optimization of clinical practice guidelines. What is Known: • There is no international consensus on which salivary glands to initially inject with BoNT-A to treat paediatric drooling. What is New: • Concluding on the optimal initial BoNT-A treatment based on literature is currently infeasible. There is considerable heterogeneity in outcome measures used to quantify anterior drooling.and clinical characteristics of children treated with intraglandular BoNT-A are generally insufficiently reported. • Consensus-based sets of outcome measures and patient characteristics should be developed and implemented.

Comparative Efficacy and Side Effect Profiles of Interventions for Pediatric Saliva Control: A Cohort Study.

OBJECTIVE: To compare efficacy and side effect profile data on conservative, behavioral, pharmacological, and surgical treatments used for pediatric saliva control. STUDY DESIGN: A cohort study of children (n = 483) referred to a specialty Saliva Control service between May 2014 and November 2019 was performed, using quantitative data from pretreatment and post-treatment questionnaires (the Drooling Impact Scale [DIS], Drooling Rating Scale [DRS]) and recording of side effects. Overall, 483 children were included; treatment choices were based on published international guidelines. RESULTS: The greatest improvement was seen after intraglandular botulinum toxin A (BTX-A) injections (n = 207; 551 courses; mean DIS change, 34.7; 95% CI = 29.2-35.7) or duct transpositional surgery (n = 31; mean change in DIS, 29.0; 95% CI, 22.3-35.7). Oral anticholinergics were associated with good outcomes, with no significant statistical difference between glycopyrronium bromide (n = 150; mean DIS change, 21.5; 95% CI, 19.1-24.0) or trihexyphenidyl (n = 87; mean DIS change, 22.4; 95% CI, 18.9-25.8). Inhaled ipratropium bromide was not as efficacious (n = 80; mean DIS change, 11.1; 95% CI, 8.9-13.3). Oromotor programs were used in a selected group with reliable outcomes (n = 9; mean DIS change, 13.0). Side effects were consistent with previous studies. Overall, in cases of milder severity, enterally administered therapies provided a good first-line option. With more severe problems, BTX-A injections or saliva duct transpositional surgery were more effective and well tolerated. CONCLUSIONS: We describe a large, single-center pediatric saliva control cohort, providing direct comparison of the efficacy and side effect profiles for all available interventions and inform clinical practice for specialists when considering different options. BTX-A injections or saliva duct transpositional surgery seem to be more effective for saliva control that is more severe.

Effect of salivary fluid characteristics on the physical features of in vitro bread bolus: From the absence of saliva to artificially simulated hypersalivation.

Saliva facilitates food oral processing, bolus formation, swallowing, and sensory perception, in addition to contributing to oral health and phonation. Ageing, health affections, and polymedication are among many causes altering salivary production, modifying the mastication process, the food impregnation ratio, and in turn altering the characteristics of the bolus, swallowing, and digestion. In this in vitro work, using the AM2 masticator apparatus, which replicates the mechanical actions taking place while chewing solid foods and produces realistic food bolus in various oral conditions, we investigated the effect of salivary fluid characteristics, i.e., composition, quantity (from absence to hypersalivation), temperature, and enzymatic action, on the physical characteristics (i.e., particle size distribution (PSD), bolus mass, salivary fluid content) of in vitro boluses of Traditional French baguette. A ready-to-swallow bolus of baguette displayed on average a d50 value (median particle size by mass) of 4.1 ± 0.4 mm, with saliva fluid constituting âˆ¼ 35 % of the final bolus mass. The absence of saliva in mouth led to a deficient oral processing, forming bread boluses constituted by extremely big particles (ca. 80 % of particles had a size > 7.1 mm) that likely cannot be swallowed safely. On the contrary, an excess of saliva favoured an excessive breaking down of bread, leading to bread boluses constituted by smaller particles than those formed under healthy salivary conditions (d50 decreased from 4.1 mm to 3.1 mm), having a higher salivary fluid content (+10 %). On the other hand, the salivary fluid temperature did not affect PSD, d50, bolus mass, or salivary fluid content of in vitro bread boluses, however, the addition of human salivary α-amylase did, favouring particle size reduction (d50 decreased to 2.6 mm). Therefore, beyond the correlation between bolus hydration by saliva and food properties such as hardness and moisture content, our findings indicate that the quantity of salivary fluid present in the oral cavity and the enzymatic activity of salivary α-amylase during bread mastication significantly influence both the particle size distribution and the fluid content of bread boluses, ultimately determining the physical properties of the bolus and, therefore, potentially impacting the subsequent swallowing process.

The role and mechanism of tight junctions in the regulation of salivary gland secretion.

Tight junctions (TJs) are cell-cell interactions that localize at the most apical portion of epithelial/endothelial cells. One of the predominant functions of TJs is to regulate material transport through paracellular pathway, which serves as a selective barrier. In recent years, the expression and function of TJs in salivary glands has attracted great interest. The characteristics of multiple salivary gland TJ proteins have been identified. During salivation, the activation of muscarinic acetylcholine receptor and transient receptor potential vanilloid subtype 1, as well as other stimuli, promote the opening of acinar TJs by inducing internalization of TJs, thereby contributing to increased paracellular permeability. Besides, endothelial TJs are also redistributed with leakage of blood vessels in cholinergic-stimulated submandibular glands. Furthermore, under pathological conditions, such as Sjögren's syndrome, diabetes mellitus, immunoglobulin G4-related sialadenitis, and autotransplantation, the integrity and barrier function of TJ complex are impaired and may contribute to hyposalivation. Moreover, in submandibular glands of Sjögren's syndrome mouse model and patients, the endothelial barrier is disrupted and involved in hyposecretion and lymphocytic infiltration. These findings enrich our understanding of the secretory mechanisms that link the importance of epithelial and endothelial TJ functions to salivation under both physiological and pathophysiological conditions.

Evaluation and Comparison of the Effectiveness of Atropine Eye Drops, Ipratropium Bromide Nasal Spray, and Amitriptyline Tablet in the Management of Clozapine-Associated Sialorrhea in Patients With Refractory Schizophrenia: A Randomized Clinical Trial.

PURPOSE: Clozapine, a second-generation antipsychotic medication, is mainly indicated for managing treatment-resistant schizophrenia. Among all the nonthreatening adverse effects of clozapine, sialorrhea is a stigmatizing complication occurring in approximately 31.0% to 97.4% of patients. In this study, 2 topical agents (atropine eye drop and ipratropium nasal spray) and a systemic medication (amitriptyline) were compared simultaneously for the management of clozapine-associated sialorrhea. METHODS: We conducted a randomized, single-blinded, non-placebo-controlled clinical trial from June 2022 to January 2023. Eligible patients were randomly allocated into 3 mentioned groups. Patients were monitored for sialorrhea weekly based on scales, including the Toronto Nocturnal Hypersalivation Scale, Clinical Global Impression-Improvement, and Clinical Global Impression-Severity for 1 month. Possible adverse drug reactions and adherence were also recorded. RESULTS: Twenty-four patients, including 6, 10, and 8 individuals in ipratropium bromide nasal spray, atropine eye drop, and amitriptyline groups, completed the study, respectively. The cohort's demographic, baseline clinical, and sociocultural characteristics were comparable among the 3 groups. Within-group comparisons, between times baseline and week 4, demonstrated that significant differences were in groups atropine and amitriptyline based on Toronto Nocturnal Hypersalivation Scale, in 3 groups based on Clinical Global Impression-Improvement, and also in only-atropine group based on Clinical Global Impression-Severity. Likewise, between-group comparisons showed that atropine was significantly more effective in clozapine-associated sialorrhea management than amitriptyline and ipratropium, in the first 2 weeks and second 2 weeks of study, respectively. Regarding safety, the interventions were tolerated relatively well. CONCLUSIONS: Conclusively, atropine is more efficacious than amitriptyline, within the first 2 weeks of study and also relative to ipratropium, overall. As time effect was significant between atropine and amitriptyline, according to analysis of covariance test, further investigation with longer follow-up duration would be prudent. In addition, expanding patient population with larger sample size should be conducted for more precision.