Intraglandular application of botulinum toxin leads to structural and functional changes in rat acinar cells

Alteration of myoepithelial cells during botulinum toxin type A-inhibited salivary secretion

OBJECTIVE

Intraglandular injection of botulinum toxin type A (BoNT/A) effectively treats sialorrhea. Myoepithelial cells (MECs) are essential for salivary secretion. The role of MECs in BoNT/A-inhibited salivary secretion, and its underlying mechanisms remain unknown.

MATERIALS AND METHODS

BoNT/A was injected into rat submandibular glands (SMGs). At 1, 2, 4, 8, and 12 weeks postinjection, salivary flow rate of SMGs was measured. Electron microscopy, immunohistochemistry, immunofluorescence, and Western blot analysis were used to detect morphological and functional changes in MECs and chemical denervation in SMGs.

RESULTS

BoNT/A temporarily decreased salivary secretion in rat SMGs and this inhibitory effect lasted 4 weeks. During the inhibitory period, MECs atrophied and expressed reduced α-smooth muscle actin (α-SMA), vimentin, and phosphorylated myosin light chain 2 (p-MLC2), suggesting that BoNT/A attenuated MEC contractility. Furthermore, BoNT/A cleaved synaptosome-associated protein 25 (SNAP-25) and decreased the expression and activity of acetylcholinesterase (AChE), indicating that BoNT/A-induced chemical parasympathetic denervation of SMGs by cleaving SNAP-25.

CONCLUSIONS

BoNT/A temporarily caused MEC atrophy and decreased MEC contractility in rat SMGs, which contributed to reversible inhibition of salivary secretion. The underlying mechanisms involved temporary parasympathetic denervation caused by SNAP-25 cleavage. These findings provide new insights into the mechanisms of BoNT/A-inhibited salivary secretion.

The Volumetric Effect of Botulinum Toxin Type A Injection on the Parotid Gland: A Randomized Controlled Trial

BACKGROUND

Botulinum neurotoxin type A (BTX-A) to the masseter muscle is a useful tool for the aesthetic narrowing of the width of the lower face. The administration of BTX-A to visible parotid glands is also effective to reduce lower facial width. However, no studies have quantitatively analyzed the effect of BTX-A on the parotid glands.

METHODS

The purpose of this study was to confirm the impact of BTX-A injection on the parotid gland and to suggest the effective dosage of BTX-A in facial slimming. This study was conducted by selecting patients who desired facial slimming from among patients who required surgery for a facial bone fracture. Patients undergoing BTX-A injection were randomized to high-dose, low-dose, and placebo groups, and different doses of BTX-A for each group were injected into both parotid glands during facial bone surgery.

RESULTS

A total of 30 patients were enrolled in this study. Ten patients in the high-dose group, eight in the low-dose group, and nine in the control group completed the clinical trial. There were significant changes in both the high- and low-dose groups compared with the control group ( P < 0.001, P < 0.001), and in interaction of time and group ( P < 0.001). Volume recovery after 3 months was found in 7.6% in the high-dose group and in 4.8% in the low-dose group.

CONCLUSION

BTX-A injection into parotid glands can be an effective treatment option in managing salivary gland enlargement for lower face contouring.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Botox for the prevention of radiation-induced Sialadenitis and xerostomia in head and neck cancer patients: A pilot study

BACKGROUND

To determine the safety of Botox and its potential effect on alleviating radiation therapy (RT)-induced sialadenitis in head and neck cancer patients.

METHODS

Twenty patients with stage III/IV head and neck cancer were randomized to receive Botox or saline injections into both submandibular glands (SMG). There were three visits: one before RT (V1); 1 week after RT (V2); and 6 weeks after RT (V3), each of which included saliva collection, a 24-h dietary recall, and a quality-of-life survey.

RESULTS

No adverse events were observed. While the control group was much older, the Botox group more commonly underwent induction chemotherapy compared with controls. From V1 to V2, salivary flow decreased in both groups, but only in the control group from V1 to V3. CXCL-1 (GRO), a neutrophil chemoattractant, was lower in the Botox group compared with the control group at V3.

CONCLUSION

Botox can be safely administered to the salivary glands prior to external beam radiation without observed complications or side-effects. After an initial reduction in salivary flow following RT, the Botox group showed lack of further flow reduction compared with controls. The inflammatory marker CXCL 1, which was reduced in the in Botox group at V3, may be a candidate for further studies of radiation-induced sialadenitis.

Cosmetic Treatment Using Botulinum Toxin in the Oral and Maxillofacial Area: A Narrative Review of Esthetic Techniques

Botulinum toxin (BoNT) is an anaerobic rod-shaped-neurotoxin produced by Clostridium botulinum, that has both therapeutic and lethal applications. BoNT injection is the most popular cosmetic procedure worldwide with various applications. Patients with dynamic wrinkles in areas such as the glabella, forehead, peri-orbital lines, nasal rhytides, and perioral rhytides are indicated. Excessive contraction of muscles or hyperactivity of specific muscles such as bulky masseters, cobble stone chins, gummy smiles, asymmetric smiles, and depressed mouth corners can achieve esthetic results by targeting the precise muscles. Patients with hypertrophic submandibular glands and parotid glands can also benefit esthetically. There are several FDA-approved BoNTs (obabotuli-numtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, letibotulinumtoxinA, prabotulinumtox-inA, daxibotulinumtoxinA, rimbotulinumtoxinB) and novel BoNTs on the market. This paper is a narrative review of the consensus statements of expert practitioners and various literature on the injection points and techniques, highlighting both the Asian and Caucasian population separately. This paper can serve as a practical illustrative guide and reference for optimal, safe injection areas and effective doses for application of BoNT in the face and oral and maxillofacial area. The history of BoNT indications, contraindications, and complications, and the merits of ultrasonography (US)-assisted injections are also discussed.

Drug Therapeutics Delivery to the Salivary Glands: Intraglandular and Intraductal Injections

Salivary gland hypofunction and xerostomia following pathological conditions like Sjogren's syndrome or head and neck radiotherapy usually lead to tremendous impairment of oral health, speech, and swallowing. The use of systemic drugs to alleviate the symptoms of these conditions has been associated with various adverse effects. Techniques of local drug delivery to the salivary gland have grown enormously to address this problem properly. The techniques include intraglandular and intraductal injections. In this chapter, we will provide a review of the literature for both techniques while incorporating our lab experience in using them.

Diagnosis, Prevention, and Treatment of Radiotherapy-Induced Xerostomia: A Review

In patients with head and neck cancer, irradiation (IR)-sensitive salivary gland (SG) tissue is highly prone to damage during radiotherapy (RT). This leads to SG hypofunction and xerostomia. Xerostomia is defined as the subjective complaint of dry mouth, which can cause other symptoms and adversely affect the quality of life. In recent years, diagnostic techniques have constantly improved with the emergence of more reliable and valid questionnaires as well as more accurate equipment for saliva flow rate measurement and imaging methods. Preventive measures such as the antioxidant MitoTEMPO, botulinum toxin (BoNT), and growth factors have been successfully applied in animal experiments, resulting in positive outcomes. Interventions, such as the new delivery methods of pilocarpine, edible saliva substitutes, acupuncture and electrical stimulation, gene transfer, and stem cell transplantation, have shown potential to alleviate or restore xerostomia in patients. The review summarizes the existing and new diagnostic methods for xerostomia, along with current and potential strategies for reducing IR-induced damage to SG function. We also aim to provide guidance on the advantages and disadvantages of the diagnostic methods. Additionally, most prevention and treatment methods remain in the stage of animal experiments, suggesting a need for further clinical research, among which we believe that antioxidants, gene transfer, and stem cell transplantation have broad prospects.

Safety of High-Dose Botulinum Toxin Injections for Parotid and Submandibular Gland Radioprotection

Botulinum Toxin injections into salivary glands (SG) up to a total dose of 100 units IncobotulinumtoxinA (IncoA) represent the treatment of choice for sialorrhea. However, BTX might also protect SG against sialotoxic radioligand cancer therapies. The radioligand Actinium-225-PSMA effectively targets Prostate Cancer (PCa) metastases but inevitably destroys SG due to unintended gland uptake. A preliminary case series with regular-dose IncoA failed to reduce SG PSMA-radioligand uptake. We therefore increased IncoA dosage in combination with transdermal scopolamine until a clinically relevant SG PSMA-radioligand uptake reduction was achieved. Ten consecutive men with metastasized PCa refractory to all other cancer therapies received gradually increasing IncoA dosages as part of a compassionate use PSMA-radioligand-therapy trial. The parotid gland received six and the submandibular gland three injection points under ultrasound control, up to a maximum of 30 units IncoA per injection point. A maximum total dose of 250 units IncoA was applied with up to 170 units per parotid and 80 units per submandibular gland. Treatment was well tolerated and all side-effects were non-serious. The most frequent side-effect was dry mouth of mild severity. No dysphagia, facial weakness, chewing difficulties or systemic side-effects were observed. SG injections with IncoA up to a total dose of 250 units are safe when distributed among several injection-points under ultrasound control by an experienced physician. These preliminary findings lay the basis for future trials including BTX as major component for SG protection in established as well as newly emerging radioligand cancer therapies.

Lacrimal Gland Botulinum Toxin Injection Versus Simple Glandular Needling: Histopathological and Electron Microscopic Evidence and Potential Clinical Implications

PURPOSE

To investigate the histopathological and ultrastructural changes in the lacrimal glands (LGs) of rabbits following either botulinum toxin (BTX) injection or simple glandular needling.

METHODS

Twenty-four LGs of 24 eyes of 12 healthy New Zealand white rabbits were included in the study. Of these, 4 LGs of 4 eyes of 2 rabbits were used as controls. In the intervention group, all the right LG received 5 U in 0.1 ml of BTX-A (Botox, Allergan, Dublin, Ireland) and the left LG received simple glandular needling under general anesthesia. The BTX-A was injected directly into the LG via the transconjunctival route under direct visualization. For simple needling, 5 LG passes were made through a single-entry point using a 29-gauge needle mounted on an empty tuberculin syringe. The rabbits did not receive any postoperative medications other than lubricants. The rabbits were sacrificed at 8 weeks and the 20 treated and 4 control LG's were retrieved for histopathological and transmission electron microscopic (TEM) analysis as per standard protocols.

RESULTS

In comparison to the control LG samples, both the treated groups showed pathological changes, which were more pronounced in the simple needling group. The BTX-A-treated LGs showed mild to moderate acinar atrophy, few degenerating acini and patchy chronic inflammatory infiltrates with thick hyalinized collagen within the glandular stroma. TEM analysis showed the cytosol of few acinar cells to contain vacuoles and autophagosomes with marginal chromatin condensation of the nucleus and an eccentric nucleolus. The LGs treated with simple needling showed marked pathological changes which include moderate to severe, focal, and diffuse acinar atrophy, dense stromal fibrosis, inflammatory infiltrates, and peri-vasculitis. TEM analysis showed focal disorganized acinar morphology, loss of intra-acinar and ductal architecture, and needle track zones with surrounding fibrotic areas.

CONCLUSIONS

Histopathological and ultrastructural changes were noted in the LGs treated with BTX-A and simple glandular needling. Simple needling of the LG has the prospect to be an effective and cheaper alternative to BTX-A.

Theranostics of prostate cancer: from molecular imaging to precision molecular radiotherapy targeting the prostate specific membrane antigen

Alterations at the molecular level are a hallmark of cancer. Prostate cancer is associated with the overexpression of prostate-specific membrane antigen (PSMA) in a majority of cases, predominantly in advanced tumors, increasing with the grade or Gleason's score. PSMA can be selectively targeted using radiolabeled PSMA ligands. These small molecules binding the PSMA can be radiolabeled with γ-emitters like ^99mTc and ¹¹¹In or positron emitters like ⁶⁸Ga and ¹⁸F for diagnosis as well as with their theranostic pairs such as ¹⁷⁷Lu (β-emitter) or ²²⁵Ac (α-emitter) for therapy. This review summarizes the theranostic role of PSMA ligands for molecular imaging and targeted molecular radiotherapy, moving towards precision oncology.

Percutaneous Salivary Gland Ablation using Ethanol in a Rat Model

Objectives

Sialorrhea is a common health and psychosocial problem for children with neuromuscular dysfunction secondary to a variety of disorders such as cerebral palsy. Current accepted treatments include the injection of botulinum toxin into the submandibular glands for temporary symptom relief. The purpose of this study is to demonstrate the feasibility of percutaneous ethanol injection for longer lasting salivary gland ablation in an animal model.

Material and Methods

Twenty rats were used in this study. In each rat, 98% ethanol was injected into the right submandibular gland under ultrasound guidance. No intervention was performed on the left gland, which served as the control. Ten rats were sacrificed and glands evaluated at three weeks, with the remaining 10 rats sacrificed and evaluated at three months. Unpaired, 1-tailed T-tests were used to analyse the data.

Results

Ethanol injections induced a significant and sustained reduction in salivary gland size. Treated glands were 41% smaller by mass than untreated controls in the 10 rats sacrificed at three weeks (P < 0.001). Treated glands were 43% smaller by mass than untreated controls in the 10 rats sacrificed at three months (P < 0.001). Qualitative histologic analysis demonstrated extensive parenchymal damage, inflammation, and fibrosis at both three week and three month time points.

Conclusions

Using a rat model, we demonstrated dramatic and sustained submandibular gland damage after percutaneous injection of ethanol.

Recent developments in clinical trials of botulinum neurotoxins

Botulinum neurotoxins (BoNTs) are increasingly used in clinical practice for several indications. Following the pioneering years of discoveries, the recent years have witnessed an increase of new indications and new toxin brands. We review here the clinical trials on BoNTs performed since 2014 and put them into perspective. We also review the ongoing trials listed by the National Institutes of Health registry (Clinicaltrials.gov). The following indications are reviewed here: blepharospasm, cervical dystonia, spasticity, cerebral palsy, urinary incontinence, headache, topical formulations, postoperative cardiac arrhythmia, keloids and scars. For each of these indications the latest trials are reviewed and commented.

A review on use of botulinum toxin for intractable lacrimal drainage disorders

PURPOSE

To review the published literature on botulinum toxin (BTX) for epiphora secondary to refractory lacrimal drainage disorders.

METHODS

The authors performed a Pub Med search of all articles published in English on BTX injection into lacrimal gland for epiphora secondary to lacrimal drainage disorders. Relevant cross-references were obtained from the resultant studies. Data reviewed included demographics, indications, dose of BTX, number of injections, transconjunctival or transcutaneous route, outcomes and complications. Animal experiments of BTX into lacrimal gland were included and analyzed separately.

RESULTS

Botulinum toxin injection into lacrimal gland, in animal studies, has shown to reduce the tear volume significantly lasting for approximately a month without any histological changes. The major indications have been refractory canalicular obstructions and functional epiphora. The commonly used dose was 2.5 U. Outcomes in the few studies published are encouraging with transient ptosis being the most common complication.

CONCLUSIONS

Botulinum toxin into the lacrimal gland is a minimally invasive alternative in cases of refractory epiphora secondary to lacrimal drainage disorders. In these subsets of patients, the reported concentrations, dosage and outcome measures are variable and need larger studies for standardization.

Histological and immunohistochemical findings of the action of botulinum toxin in salivary gland: systematic review

The treatment of sialorrhea is necessary for the constant risks posed by hypersalivation. A new therapeutic option comes up with the application of botulinum toxin in salivary glands. However, little is known about its mechanism of action in glandular tissue. Based on the above, this work had the objective to systematically review the literature about the action of botulinum toxin on submandibular and parotid salivary glands tissues. Electronic search was performed in databases of great relevance for this study (PubMed, SciELO, HighWire, Crossref, Scopus, Science Direct, MEDLINE, OLDMEDLINE, Serials Database, NLM Catalog, LILACS and IBECS). Inclusion and exclusion criteria for articles were established, and a total number of 14 articles were selected and used. There are few publications that clarify how the salivary gland acini behave with application of botulinum toxin. Although, the immunohistochemical findings were consistent among authors, showing weak immunoreactivity in glands treated with botulinum toxin. Histometric data are divergent, requiring more detailed studies to answer the questions about the efficacy and safety of botulinum toxin in salivary glands.

[Interests of the ultrasound-guidance in the treatment of drooling through botulinum toxin injections, our experience over 10 years]

OBJECTIVES

To report about our 10 years' experience about the treatment of drooling by ultrasound guided botulinum toxin injections.

MATERIAL AND METHODS

Retrospective monocentric study including all the patients suffering from drooling and treated by ultrasound-guided botulinum toxin injections into the salivary glands between 2004 and 2015. The etiology of r drooling, the doses of toxin, the injected glands, the size of the glands measured by ultrasonography, the effectiveness of the treatment and the side effects were assessed.

RESULTS

Two hundred and ninety-two injections sessions were performed in 61 patients. Exactly 70.5 % of patients reported an improvement after the first session. Parkinson's disease was the main etiology of drooling (43 % of the patients). Eleven patients reported side effects. The salivary gland volume reduced after treatment in 46 % of the patients.

DISCUSSION

The interest of ultrasound-guidance is to make sure about the intraglandular injection, to lower the risk for extraglandular diffusion of the toxin responsible for swallowing disorders and to allow for an adaptation of the doses to the volume of the salivary glands, which may vary during treatment.

Aesthetic Applications of Botulinum Toxin A in Asians: An International, Multidisciplinary, Pan-Asian Consensus

Background:

Botulinum toxin type A remains the most popular nonsurgical aesthetic treatment worldwide. Previous consensus statements have focused on Caucasians and on Koreans as generally representative of Asians. However, indications and dosages vary among different ethnic groups. This publication reports the results of a multidisciplinary, pan-Asian consensus focusing on incobotulinumtoxinA.

Methods:

A consensus group of plastic surgeons and dermatologists from Asia, Europe, and the United States convened for a live meeting in Asia, followed by a questionnaire-based Delphi procedure. Treatment of Asians in both their native countries and countries of migration was discussed.

Results:

For most items, the group achieved a majority consensus. A number of treatment indications, strategies, and dosages were identified in Asians, which are distinct to those previously described for Caucasians due to differences in facial morphotypes, anatomy, and cultural expectations. The group also formulated position statements for intradermal botulinum toxin type A (“mesotoxin”), body shaping with the calves as a paradigm, and reduction of parotid glands. While Asians have previously been considered a homogeneous group for the purposes of aesthetic treatment, this publication considers regional variations. A new classification of Asian facial morphotypes is proposed to aid treatment planning and implementation.

Conclusions:

This is the first pan-Asian consensus for aesthetic use of botulinum toxin type A. Its unique objective is to optimize treatment safety and efficacy for patients of complete or part-Asian ancestry in all regions. The recommendations for incobotulinumtoxinA may be extended with care to other botulinum toxin formulations.

Intraprostatic Botulinum Neurotoxin Type A Injection for Benign Prostatic Hyperplasia-A Spotlight in Reality

Botulinum toxin is a neurotoxin produced by the bacterium Clostridium botulinum. It inhibits the release of acetylcholine and other neurotransmitters from the nerve terminal. Botulinum toxin, specifically toxin type A (BoNT-A) has been used since the 1970s to reduce the muscular hypercontraction disorders. The application of BoNT-A in urology field started from intra-bladder injection for overactive bladder, which has been recognized as third line therapy in many countries. Since prostate gland as well as bladder is under the influence of autonomic innervation, theorectically, injection of BoNT-A into the prostate induces chemo-denervation and modulation of prostate function, and reduces lower urinary tract symptoms (LUTS). This article reviews the application of BoNT-A in patients with LUTS/ benign prostatic hyperplasia (BPH) from mechanisms of action to clinical results. BoNT-A has been shown to induce prostate apoptosis, downregulation of alpha 1A receptors, and reduce contractile function of prostate in animal studies. Open studies of intraprostate BoNT-A injection have demonstrated promising results of reducing LUTS and improvement of voiding function in human LUTS/BPH, however, intraprostatic BoNT-A injection did not perform better than the placebo group in recent publications of placebo controlled studies. We suggested that BoNT-A prostate injection might benefit selected population of BPH/LUTS, but it is unlikely to be an effective therapy for general population of male LUTS/BPH.

Safety and Efficacy of Botulinum Toxin to Preserve Gland Function after Radiotherapy in Patients with Head and Neck Cancer: A Prospective, Randomized, Placebo-Controlled, Double-Blinded Phase I Clinical Trial

This prospective, randomized, placebo-controlled, double-blinded phase I clinical trial investigates safety and efficacy of botulinum toxin (BoNT) to preserve gland function after radiotherapy in patients with head and neck cancer. Twelve patients with advanced head and neck cancer were injected with BoNT into the submandibular glands prior to primary radiochemotherapy. Six patients received BoNT/A and 6 patients BoNT/A and B, half of each subgroup into their left and the other half into their right gland. As an internal control, sodium chloride was injected into the respective contralateral gland (placebo). For the evaluation of the salivary gland function, technetium pertechnetate salivary gland scintigraphy was performed before and after the end of radiotherapy. BoNT/A and B were well tolerated. Analysis of the scintigraphic data revealed no statistically significant difference between BoNT and placebo regarding the scintigraphic uptake difference (pBoNT/A = 0.84 and pBoNT/A-B = 0.56 for BoNT/A vs. placebo and BoNT/A-B vs. placebo, respectively). We also found no significant difference in treatment between BoNT and placebo in terms of salivary excretion fraction (pBoNT/A = 0.44; pBoNT/A-B = 0.44). This study demonstrates that BoNT can be safely combined with radiochemotherapy. Dosing and timing of BoNT injection should be further investigated for efficacy analysis.

Repeated treatments of drooling with botulinum toxin B in neurology

OBJECTIVES

To investigate efficacy, saliva flow, and composition in repeated BoNT-B treatments of drooling.

MATERIALS AND METHODS

Seventeen neurological patients (median 66 years), referred for treatment of drooling participated in this observational study. Median total doses of 4000 units botulinum toxin type B (BoNT-B, Neurobloc(®)) were injected with at least 3 months intervals into parotid and submandibular glands using ultrasound guidance. Measures of drooling and saliva collection for analysis were obtained before treatment, and 6, 12, and eventually 18 weeks after.

RESULTS

Number of treatment series in each patient was 1-7. Compared to baseline, saliva flow rate and drooling were reduced 30-70% 6 weeks after treatment in the first series, while sodium, chloride, and total protein increased 20-80% (t-tests; P < 0.05). After 12 weeks, drooling was still significantly reduced, saliva flow tended to be, and saliva composition was back to baseline. Frequent side effects were viscous saliva and dry mouth. Due to fading effect in eight patients, individual decisions were taken to change from BoNT-B to BoNT-A. Similarly, the outcome was significantly reduced over time in six patients completing five subsequent BoNT-B treatment series (ANOVA; P < 0.05).

CONCLUSION

In the first series, BoNT-B treatment resulted in marked reduction of drooling and saliva flow rate with some relapse after 12 weeks. The viscous saliva was ascribed to increased total protein content and compensatory mechanisms related to ß-adrenergic receptor-specific actions. With patients needing long-term treatment, it should be noted that the efficacy of repeated BoNT-B may fade with time.

Botulinum toxin A inhibits salivary secretion of rabbit submandibular gland

Botulinum toxin A (BTXA) has been used in several clinical trials to treat excessive glandular secretion; however, the precise mechanism of its action on the secretory function of salivary gland has not been fully elucidated. In this study, we aimed to investigate the effect of BTXA on secretion of submandibular gland in rabbits and to identify its mechanism of action on the secretory function of salivary gland. At 12 weeks after injection with 5 units of BTXA, we found a significant decrease in the saliva flow from submandibular glands, while the salivary amylase concentration increased. Morphological analysis revealed reduction in the size of acinar cells with intracellular accumulation of secretory granules that coalesced to form a large ovoid structure. Expression of M3-muscarinic acetylcholine receptor (M3 receptor) and aquaporin-5 (AQP5) mRNA decreased after BTXA treatment, and distribution of AQP5 in the apical membrane was reduced at 1, 2 and 4 weeks after BTXA injection. Furthermore, BTXA injection was found to induce apoptosis of acini. These results indicate that BTXA decreases the fluid secretion of submandibular glands and increases the concentration of amylase in saliva. Decreased expression of M3 receptor and AQP5, inhibition of AQP5 translocation, and cell apoptosis might involve in BTXA-reduced fluid secretion of submandibular glands.

Evaluation of ethanolamine oleate sclerotherapy on the submandibular glands of canines as a potential therapy for sialorrhea

BACKGROUND

Sialorrhea can have major negative effects on the physical and social well-being. Sclerotherapy may be useful in patients with sialorrhea by decreasing the amount of saliva production. The aim of this study was to test the effect of ethanolamine oleate (EO) in an experimental model as a preliminary step for its application in humans.

METHODS

Histopathological and morphometric analysis of submandibular glands from thirteen dogs was preformed. A total of 25 glands were injected with 1ml of 2.5% EO (n=5), 1ml of 5% EO (n=5), 5ml of 2.5% EO (n=5) and 5ml of 5% EO (n=5). Five glands were used as control.

RESULTS

EO significantly induced a dose dependent scaring of the gland ending in lobular transformation (salivary gland cirrhosis). Morphometric measurements showed that 1ml of 2.5% or 5% EO significantly induced fibrosis compared to normal glands (p=0.014 and 0.021, respectively). Fibrosis significantly increased and was more apparent when a dose of 5ml of 2.5% EO or 5% EO were injected [by semi-quantitative evaluation (p=0.016 and 0.002, respectively) and morphometric measurements (p=0.016 and 0.008, respectively)]. This scarring effect was significantly associated with reduction of area of acinar cells when a dose of 1ml-5%, 5ml-2.5% or 5ml-5% EO were applied (p=0.03. 0.012 and 0.004, respectively). Moreover, ductal injury was only significant when a dose of 5ml of 5% EO was used (p=0.034). This dose and concentration (i.e. 5ml-5% EO) had a significant synergetic effect [p=0.0119].

CONCLUSION

In this model, treatment with EO proved to permanently reduce the acinar area through induction of progressive, irreversible and dose dependant scarring (medical sialoadenectomy).

Unilateral maxillary molar extraction influences AQP5 expression and distribution in the rat submandibular salivary gland

OBJECTIVE

Mastication has been regarded as a crucial factor for maintaining the morphology and function of secretion in salivary glands. Although it is known that occlusion affects mastication, the detailed process for how occlusal changes affect the secretory function of salivary glands is still unknown. Aquaporin 5 (AQP5) is a membrane protein that forms water channels, and plays an important role in water transport. In this study, we investigated the structural changes and alterations in the expression and distribution of AQP5 in the rat submandibular salivary gland (SMG) under occlusal hypofunction after unilateral molar extraction.

METHODS

Seven-week-old male Wistar rats (n = 36) were used in the study. In the experimental group, all of the right maxillary molars were extracted. Rats with no molar extraction were used as the control group. The rats were euthanized at 7, 14 or 28 days after the procedure, and the right SMGs were isolated and subjected to histological analyses. The expression and distribution of AQP5 were detected by immunohistochemistry.

RESULTS

Morphological analyses revealed hypertrophic changes in the acinar cells in the experimental group. Immunohistochemical staining of AQP5 was detected in the apical membrane (APM) and intercellular secretory canaliculi of acinar cells in both groups. On the other hand, the AQP5 expression in the APM and intercellular secretory canaliculi of acinar cells was less prominent in the experimental group than in the control group.

CONCLUSIONS

The present findings suggest that unilateral molar extraction has significant influences on the function of water transport in the rat SMG.

Effect of botulinum toxin type a on morphology of salivary glands in patients with cerebral palsy

Objective

To investigate the effect of botulinum toxin type A (BTXA) on drooling and the morphologic change of the salivary gland in patients with cerebral palsy.

Method

Eight cerebral palsy patients suffering from severe drooling participated in this study. BTXA was injected into both submandibular and parotid glands under intravenous sedation and with ultrasound guidance (1 unit/gland/kg: maximum 100 units) in an outpatient or inpatient procedure. The severity of drooling was measured before injection and 3 weeks after injection using the Teacher Drooling Scale, the Drooling Score-severity, frequency and the Visual Analog Scale. To investigate the morphologic change of the salivary glands, the size of salivary glands were measured before injection and 3 weeks after injection using computed tomography of the neck. The measurement values were analyzed by Wilcoxon signed rank test.

Results

Statistically significant improvements were shown in all three parameters for assessing the severity of drooling after BTXA injections (p<0.05). Size of the salivary glands were significantly decreased at 3 weeks after BTXA injection (p<0.05).

Conclusion

Salivary gland injection with BTXA could be a useful treatment method to reduce drooling in patients with cerebral palsy and decreased size of salivary glands may partially explain the mechanism.

Treatment of severe drooling with botulinum toxin in amyotrophic lateral sclerosis and Parkinson's disease: efficacy and possible mechanisms

OBJECTIVE

Drooling in neurodegenerative diseases is associated with social impediment. Previous treatments of drooling have little effect or are effective but with severe side effects. Therefore, there is a need to test new methods such as the use of botulinum toxin type A (BTX-A).

MATERIAL AND METHODS

This open, prospective study deals with treatment of drooling in 12 patients with amyotrophic lateral sclerosis and three with Parkinson's disease. Injections of BTX-A (Botox) were given into the parotid (25-40 units) and submandibular (15-30 units) glands with ultrasonographic guidance. After BTX-A treatment, the patients were followed for 2 months with evaluations every second week by means of self-assessed rating scales for drooling intensity, discomfort and treatment effect, and determination of unstimulated whole saliva (UWS) flow rate, and inorganic and organic UWS composition. The treatment was repeated up to four times, but seven patients dropped out shortly after the first treatment due to marked worsening of their disease-related condition.

RESULTS

Drooling and flow were reduced (P < 0.05) 2 weeks after treatment, without side-effects. The maximal reductions during the observation period were 40% for drooling and 30% for flow. There was a systematic variation in flow during the observation period, with an initial decrease and then an increase followed by a second decrease. Amylase activity and total protein concentration generally increased with decreasing flow (P ≤ 0.03).

CONCLUSION

Inhibition of acetylcholine release from postganglionic parasympathetic nerve endings by injection of BTX-A into salivary glands seemed useful for secondary sialorrhoea, although cyclic variations in flow may occur, possibly due to transitory sprouting and regeneration.

Pediatric rehabilitation: 1. Common medical conditions in children with disabilities

OBJECTIVE

This self-directed learning module focuses on the physiatric management of the common morbidities associated with pediatric traumatic brain injury and cerebral palsy. It is part of the study guide on pediatric rehabilitation in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation and pediatric medicine. The goal of this article is to enhance the learner's knowledge regarding current physiatric management of complications related with pediatric traumatic brain injury and cerebral palsy.

Modification of innervation pattern by fluoroquinolone treatment in the rat salivary glands

Fluoroquinolone antibiotics (FQAs) are widely used in dental and medical therapy. Despite their known severe adverse actions on the central and peripheral nervous system, little attention has been directed toward the potential toxic side effects of these compounds on the oral tissues. As the saliva secretion is controlled by the nervous system and neuropeptides, the neurotoxic effect of pefloxacin (PEF), a representative member of FQAs, was studied in rats in the present work. Previously, we demonstrated a significant weight loss of parotid gland tissue, a marked decrease in 3H-thymidine incorporation, a decreased volume of saliva and amylase activity of the glandular tissue in response to PEF. Animals received intraperitoneal injection of PEF (20 mg/100 g body weight daily) for 3 and 7 days. Normal histology, and neurofilament 200, substance P (SP) and calcitonin gene-related polypeptide (CGRP) containing nerve fibers were detected with immunohistochemical methods. A marked decrease of the weights in salivary glands and the acinar diameters were measured. Similarly, a strong and significant decrease of the number of SP and CGRP containing nerve fibers were detected. These findings suggest that the impaired morphology and innervation pattern of salivary glands is related to the neurotoxic adverse effect of FQA treatment.

Botulinum toxin abolishes sweating via impaired sweat gland responsiveness to exogenous acetylcholine

BACKGROUND

Botulinum toxin A (BTX) disrupts neurotransmitter release from cholinergic nerves. The effective duration of impaired sweat secretion with BTX is longer relative to that of impaired muscle contraction, suggesting different mechanisms in these tissues.

OBJECTIVES

The aim of this study was to test the hypothesis that BTX is capable of altering sweating by reducing the responsiveness of the sweat gland to acetylcholine.

METHODS

BTX was injected into the dorsal forearm skin of healthy subjects at least 3 days before subsequent assessment. On the day of the experiment, intradermal microdialysis probes were placed within the BTX-treated area and in an adjacent untreated area. Incremental doses of acetylcholine were administered through the microdialysis membranes while the sweat rate (protocol 1; n = 8) or a combination of sweat rate and skin blood flow (protocol 2; n = 8) were assessed.

RESULTS

A relative absence of sweating was observed at the BTX site for both protocols (protocol 1: 0.05 +/- 0.09 mg cm(-2) min(-1); protocol 2: 0.03 +/- 0.04 mg cm(-2) min(-1), both at the highest dose of acetylcholine), while the sweat rate increased appropriately at the control sites (protocol 1: 0.90 +/- 0.46 mg cm(-2) min(-1); protocol 2: 1.07 +/- 0.67 mg cm(-2) min(-1)). Cutaneous vascular conductance increased to a similar level at both the BTX and control sites.

CONCLUSIONS

These results demonstrate that BTX is capable of inhibiting sweat secretion by reducing the responsiveness of the sweat gland to acetylcholine, while not altering acetylcholine-mediated cutaneous vasodilatation.

Botulinum toxin prevents radiotherapy-induced salivary gland damage

Radiotherapy of head and neck malignancies results in severe damage to salivary glands. Irradiation-induced sialadenitis with xerostomia leads to a significant deterioration of the quality of life which lasts life-long. Here we show in a preliminary study that intraglandular application of botulinum toxin performed prior to radiation reduces significantly the radiation induced toxicity of the glandular tissue in rats.