Systemic pilocarpine for treatment of xerostomia

Intracellular Signaling Pathways Involved in the Regulation of Gene Expression by Pilocarpine

OBJECTIVES

Pilocarpine is commonly used clinically to treat dry mouth. The long-term administration of pilocarpine reportedly improves salivary secretion more effectively than short-term administration. Therefore, we hypothesized that pilocarpine alters gene expression in salivary glands via muscarinic receptor stimulation. This study aimed to investigate the effects of pilocarpine use on gene expression mediated by mitogen-activated protein kinase (MAPK) activity.

METHODS

The effects of pilocarpine on gene expression were investigated in rats and human salivary gland (HSY) cells using several inhibitors of intracellular signaling pathways. Gene expression in the rat submandibular gland and HSY cells was determined using reverse transcription-quantitative polymerase chain reaction analysis of total RNA.

RESULTS

In animal experiments, at 7 days after pilocarpine stimulation, Ctgf and Sgk1 expressions were increased in the submandibular gland. In cell culture experiments, pilocarpine increased Ctgf expression in HSY cells. The mitogen-activated protein kinase kinase inhibitor trametinib, the Src inhibitor PP2, and the muscarinic acetylcholine receptor antagonist atropine suppressed the effect of pilocarpine on gene expression.

CONCLUSIONS

Pilocarpine enhances Ctgf and Sgk1 expressions by activating Src-mediated MAPK activity. Although further studies are required to fully understand the roles of Ctgf and Sgk1, changes in gene expression may play an important role in improving salivary secretions.

As-Needed Pilocarpine for Radiation-Induced Xerostomia in Head and Neck Cancers

OBJECTIVES

This study aimed to evaluate the efficacy of as-needed pilocarpine for the management of radiation-induced xerostomia. Additionally, the study sought to assess the side effects associated with an as-needed regimen.

METHODS

A randomized, double-blinded, placebo-controlled crossover study was conducted on patients who had undergone radiation therapy for head and neck cancers and developed xerostomia. Participants took pilocarpine or placebo as needed for symptom relief at 2 weeks per treatment, which included a one-week washout period. The primary outcome measure was the severity of dry mouth symptoms, quantified using the Xerostomia Inventory (XI). The primary outcome was the change in the XI score.

RESULTS

Among the 20 participants who completed the crossover study, there was a significant reduction in XI scores during the treatment phase with pilocarpine compared to the scores during the placebo phase. The mean difference in XI scores was -18.05 (95% CI: -17.17, -6.13, p < 0.001), with a-49.77 ± 3.22% change (p < 0.001). Only one participant withdrew due to pilocarpine side effects.

CONCLUSION

As-needed pilocarpine administration is effective in relieving symptoms of radiation-induced xerostomia, with fewer side effects and reduced treatment costs compared to fixed-dose regimens. This study guides the potential shift toward flexible dosing strategies in clinical practice, promoting enhanced patient-centered, tailored care and adherence.

LEVEL OF EVIDENCE

Level 2. According to the Oxford Center for Evidence-Based Medicine 2011 level of evidence guidelines Laryngoscope, 2024.

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.

Synthesis, Characterization, and Application of Muscarinergic M3 Receptor Ligands Linked to Fluorescent Dyes

Through the linkage of two muscarinergic M₃ receptor ligands to fluorescent tetramethylrhodamine- and cyanine-5-type dyes, two novel tool compounds, OFH5503 and OFH611, have been developed. Based on the suitable binding properties and kinetics related to the M₃ subtype, both ligand-dye conjugates were found to be useful tools to determine binding affinities via flow cytometric measurements. In addition, confocal microscopy underlined the comparably low unspecific binding and the applicability for studying M₃ receptor expression in cells. Along with the proven usefulness regarding studies on the M₃ subtype, the conjugates OFH5503 and OFH611 could, due to their high affinity to the M₁ receptor, evolve as even more versatile tools in the field of research on muscarinergic receptors.

DMA, a Small Molecule, Increases Median Survival and Reduces Radiation-Induced Xerostomia via the Activation of the ERK1/2 Pathway in Oral Squamous Cell Carcinoma

Survival, recurrence, and xerostomia are considerable problems in the treatment of oral squamous carcinoma patients. In this study, we investigated the role of DMA (5-(4-methylpiperazin-1-yl)-2-[2′-(3,4-dimethoxyphenyl)5″benzimidazoyl]benzimidazole) as a salivary gland cytoprotectant in a patient-derived xenograft mouse model. A significant increase in saliva secretion was observed in the DMA-treated xenograft compared to radiation alone. Repeated doses of DMA with a high dose of radiation showed a synergistic effect on mice survival and reduced tumor growth. The mean survival rate of tumor-bearing mice was significantly enhanced. The increased number of Ki-67-stained cells in the spleen, intestine, and lungs compared to the tumor suggests DMA ablates the tumor but protects other organs. The expression of aquaporin-5 was restored in tumor-bearing mice injected with DMA before irradiation. The reduced expression of αvβ3 integrin and CD44 in DMA alone and DMA with radiation-treated mice suggests a reduced migration of cells and stemness of cancer cells. DMA along with radiation treatment results in the activation of the Ras/Raf/MEK/ERK pathway in the tumor, leading to apoptosis through caspase upregulation. In conclusion, DMA has strong potential for use as an adjuvant in radiotherapy in OSCC patients.

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.

A Review on Xerostomia and Its Various Management Strategies: The Role of Advanced Polymeric Materials in the Treatment Approaches

The medical term xerostomia refers to the subjective sensation of oral dryness. The etiology seems to be multifactorial with the most frequently reported causes being the use of xerostomic medications, neck and head radiation, and systematic diseases (such as Sjögren’s syndrome). Xerostomia is associated with an increased incidence of dental caries, oral fungal infections, and difficulties in speaking and chewing/swallowing, which ultimately affect the oral health-related quality of life. The development of successful management schemes is regarded as a highly challenging project due to the complexity of saliva. This is why, in spite of the fact that there are therapeutic options aiming to improve salivary function, most management approaches are alleviation-oriented. In any case, polymers are an integral part of the various formulations used in every current treatment approach, especially in the saliva substitutes, due to their function as thickening and lubricating agents or, in the case of mucoadhesive polymers, their ability to prolong the treatment effect. In this context, the present review aims to scrutinize the literature and presents an overview of the role of various polymers (or copolymers) on either already commercially available formulations or novel drug delivery systems currently under research and development.

Potential Role for Combined Subtype-Selective Targeting of M1 and M3 Muscarinic Receptors in Gastrointestinal and Liver Diseases

Despite structural similarity, the five subtypes comprising the cholinergic muscarinic family of G protein-coupled receptors regulate remarkably diverse biological functions. This mini review focuses on the closely related and commonly co-expressed M₁R and M₃R muscarinic acetylcholine receptor subtypes encoded respectively by CHRM1 and CHRM3. Activated M₁R and M₃R signal via G_q and downstream initiate phospholipid turnover, changes in cell calcium levels, and activation of protein kinases that alter gene transcription and ultimately cell function. The unexpectedly divergent effects of M₁R and M₃R activation, despite similar receptor structure, distribution, and signaling, are puzzling. To explore this conundrum, we focus on the gastrointestinal (GI) tract and liver because abundant data identify opposing effects of M₁R and M₃R activation on the progression of gastric, pancreatic, and colon cancer, and liver injury and fibrosis. Whereas M₃R activation promotes GI neoplasia, M₁R activation appears protective. In contrast, in murine liver injury models, M₃R activation promotes and M₁R activation mitigates liver fibrosis. We analyze these findings critically, consider their therapeutic implications, and review the pharmacology and availability for research and therapeutics of M₁R and M₃R-selective agonists and antagonists. We conclude by considering gaps in knowledge and other factors that hinder the application of these drugs and the development of new agents to treat GI and liver diseases.

Therapeutic Strategies for Dry Mouth Management with Emphasis on Electrostimulation as a Treatment Option

Objectives

Xerostomia is a subjective sensation of dry mouth. It is commonly associated with salivary gland hypofunction. Both changes in the composition of the saliva and a reduction in the quantity secreted may be an objective finding of dry mouth. Although there are no currently available cures for the conditions resulting in dry mouth, there are several treatment options that give hope for patients who suffer from xerostomia. Individuals with some residual salivary gland function, which are contraindicated to pharmacological therapies, would benefit the most from identifying novel, alternative effective methods for stimulating production of saliva. The aim of this study was to give an overview of the latest and most relevant data related to treatment modalities for the management of dry mouth conditions. Data Resources and Study Selection. The present review was prepared by searching the National Library of Medicine database using the relevant medical terms and their combinations. A total of thirty-three studies met the inclusion criteria. Data were extracted by one author and verified by another.

Conclusion

A number of patients showed positive treatment outcomes, and the adverse effects of both electrical stimulation (ES) and acupuncture have been reported as mild and transient. In patients who have undergone radiotherapy, acupuncture is shown to increase salivation. However, in patients with Sjogren's syndrome, the effects of ES devices seem to be elusive. Moreover, due to the instability of the findings in relation to longevity of clinical effect, patient satisfaction, quality of life, and clinical effectiveness of such treatments, the results remain vague.

Salivary Glands and Periodontal Changes in a Population of Sjögren's and Sicca Syndrome Treated by Pilocarpine: A Pilot Study

Introduction

Oral administration of pilocarpine enhances salivary flow in sicca patients but its effect upstream on ultrasound (US) of salivary glands (SG) and downstream on periodontium remain unknown.

Methods

Sicca patients were prospectively included. Echostructural and vascularization of SG were assessed using B mode and pulsed Doppler (USPD). Vascularization of SG was measured using resistive index (RI) before and after stimulation by lemon juice. Echostructure (measure of glandular length in cm², evaluation of parotid and submandibular glands parenchymal abnormalities) was assessed at baseline (M0) and after 3 months (M3) of treatment with pilocarpine. A dental consultation was performed at M0 and M3 to evaluate changes in unstimulated salivary flow (USSF), stimulated salivary flow (SSF), and periodontal parameters such as modified gingival index (Lobene), plaque index (Silness), bleeding index, pocket depth, and pH.

Results

Nineteen patients were included but only 11 received pilocarpine treatment for 3 months, as six stopped pilocarpine due to side effects and two were excluded for other causes. Among the 11 patients who completed the 3-month follow-up, five had primary Sjögren’s syndrome according to the American-European’s classification criteria. As expected, statistical differences were found concerning SSF (p = 0.018) and USSF (p = 0.027) between M0 and M3 while no statistical change in both SG echostructure and vascularization or periodontal evaluation was shown.

Conclusions

Pilocarpine improved SSF and USSF measurements in sicca syndrome but no ultrasonography of major salivary glands (SGUS) structural and vascular changes were detected as well as periodontal evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-020-00263-y.

The muscarinic agonist pilocarpine modifies cocaine-reinforced and food-reinforced responding in rats: comparison with the cholinesterase inhibitor tacrine

Activation of muscarinic receptors in the brain antagonizes the actions of cocaine, blocking both its discriminative stimulus and reinforcing properties. Pilocarpine is a nonselective muscarinic agonist that is used clinically, but has not been well characterized for its actions during cocaine-reinforced behavior. This study evaluated its effects on cocaine-reinforced and food-reinforced behaviors in rats, using the cholinesterase inhibitor tacrine as a comparator. Intraperitoneal pilocarpine or tacrine at doses of 1.0 mg/kg or more attenuated self-administration of low-dose cocaine (0.1 mg/kg injection) but also increased oral movements. Pilocarpine was less potent than tacrine in decreasing responding supported by low or intermediate amounts of liquid food. Combined treatment with pilocarpine and tacrine was more effective than either compound alone in attenuating self-administration of intermediate-dose cocaine. At a low (0.66 mg/kg) dose which did not modify reinforced responding, pilocarpine increased nonspecific behavior (sniffing, rearing, and activity) in cocaine-reinforced but not in food-reinforced animals; with greater doses increasing cholinergic or gastrointestinal signs. These effects were most consistently correlated with changes in reinforcement in rats responding for cocaine relative to food-reinforced animals. Overall, pilocarpine exhibited modest selectivity for attenuating self-administration of low-dose cocaine without affecting a nondrug reinforcer.

Neuroprotective effect of lovastatin through down-regulation of pro-apoptotic Mst1 gene expression in rat model pilocarpine epilepsy

OBJECTIVE

Statins as inhibitors of HMG-CoA reductase have been recently recognized as anti-inflammatory and neuroprotective drugs. In this paper, we studied anti-apoptotic and regulatory effects of lovastatin using Pilocarpine rat model through downregulation of Mst1 (Mammalian sterile 20-like kinase 1) as a novel pro-apoptotic gene.

METHODS

The rats were divided into four groups: non-treated epileptic rats, lovastatin treated, and two vehicle groups. Racine scale was used for behavioral assessment and animals with a score of 4-5 were selected for the study. After 3 days, epileptic rats received intraperitoneal injections of lovastatin, followed by treating for 14 days. Next, they were sacrificed (28 post-first seizure) and prepared for histopathological analysis and Real-time RT-PCR.

RESULTS

The results showed that lovastatin protects Pilocarpine-induced cell death via a regulatory effect on pro-apoptotic and anti-apoptotic gene expression. The real-time PCR results showed that in the epileptic lovastatin treated group, the expression level of Mst1 significantly decreased while Nrf2 and Bcl-2 genes increased. Furthermore, histological analysis of neurodegeneration in the brain sections showed that the number of hippocampal apoptotic cells significantly decreased in the treatment groups. The results showed that the numerical density of neurons per area was significantly higher in the treated than the untreated group.

CONCLUSION

Overall, the results of this study showed that lovastatin attenuates hippocampal cell death in Pilocarpine-induced status epilepticus rat model through downregulation of the pro-apoptotic Mst1 gene.

ABBREVIATIONS

Mst1: Mammalian sterile 20-like kinase 1; Nrf2: nuclear factor erythroid 2-related factor 2; Bcl-2: B-cell lymphoma 2; HMG-CoA: 3-hydroxy-3-methylglutaryl-coenzyme A; RT-PCR: reverse transcription-polymerase chain reaction; TLE: Temporal Lobe Epilepsy; SE: status epilepticus.

Salivary hypofunction: An update on therapeutic strategies

OBJECTIVE

To perform a literature review addressing the therapeutic strategies for salivary hypofunction.

BACKGROUND

Qualitative and quantitative salivary dysfunctions predispose to changes in the oral mucosa and teeth, cause impairment to oral functions and negative impact on quality of life.

MATERIALS AND METHODS

A MEDLINE/PubMed search was conducted using the terms "Xerostomia" AND, "Saliva Artificial" OR, "Citric Acid," "Malic Acid," "Chewing Gum," "Acupuncture" OR, "Pilocarpine" OR, "Bethanechol" OR, "Cevimeline" OR, "Hyperbaric Oxygen Therapy" OR, "Stem Cell Therapy" OR "Genetic Therapy" and their Mesh Terms.

RESULTS

We selected 25 clinical trials investigating the effects of salivary substitutes, chewing gum, malic and citric acids, pilocarpine, cevimeline, bethanechol, acupuncture, hyperbaric oxygen therapy and regenerative therapies on salivary hypofunction. In most studies, the number of participants was low and the follow-up times short. The therapeutic modalities were classified according to the level of evidence on salivary dysfunction.

CONCLUSIONS

Pilocarpine and cevimeline had the strongest evidence of beneficial effect on salivary hypofunction. Citric and malic acids increase salivary flow but also increase the risk of erosion and dental caries. There are no controlled clinical trials supporting the efficacy of acupuncture, stem cell therapy and gene therapy on salivary dysfunction, although clinical observations suggest a promising effect. There is no evidence supporting salivary substitutes, chewing gum, bethanechol or hyperbaric oxygen on the treatment of salivary hypofunction.

Sialendoscopic management of autoimmune sialadenitis: a review of literature

Autoimmune diseases of major salivary glands include Sjögren's syndrome and a complex of disorders classified as immunoglobulin G4-related diseases. These pathologies are characterised by an autoimmune reaction mediated by T-helper lymphocytes that targets the ducts of exocrine glands in Sjögren's syndrome and glandular parenchyma in immunoglobulin G4-related diseases. Immunoglobulin G4-related diseases represent recently introduced multi-organ diseases that also involve the salivary glands. However, the morbid conditions once known as Mikulicz's disease and Kuttner's tumour were recently considered as two variants of immunoglobulin G4-related diseases affecting the major salivary glands ( immunoglobulin G4-related sialadenitis). This review briefly summarises the pathogenesis and clinical features of autoimmune diseases of the major salivary glands, focusing on the diagnostic and therapeutic role of sialendoscopy.

Regenerative capacity of allogenic gingival margin- derived stem cells with fibrin glue on albino rats' partially dissected submandibular salivary glands

OBJECTIVE

To evaluate the possible regenerative effect of allogenic gingival margin-derived stem cells (GMSCs) with or without autologous fibrin glue on partially dissected submandibular salivary glands of albino rats.

METHODS

Forty rats were randomly divided into four equal groups. Group I, where no operation was performed, was considered the negative control. Group II rats were considered the positive control and were subjected to a rectangular cut on the outer surface of the center right of the submandibular salivary gland and received no other treatment. Groups III and IV rats were handled as those in group II, but the cut areas of group III were filled with fibrin glue and the cut borders of group IV were injected with 1×10⁵cell/ml GMSCs and then glued with fibrin glue. Five animals from each group were euthanized at the end of the first postoperative week, while the remaining animals were euthanized at the end of the second postoperative week, i.e., end of the experiment.

RESULTS

Regeneration of ductal, acinar, and myoepithelial cells was better in group IV. A two-way ANOVA for proliferating cell nuclear antigen and α-smooth muscle actin revealed an overall significant difference between the different groups (P<0.05). In addition, an LSD post hoc test for multiple comparisons revealed a significant difference between each two groups. An independent sample t-test revealed significant differences between time periods for groups II, III, and IV, but there were no significant differences between the time periods for group I.

CONCLUSION

Injecting GMSCs at the cut borders and gluing the cut area with autologous fibrin glue ameliorates the regeneration of partially dissected submandibular salivary gland better than using fibrin glue alone.

Establishment of immortalized mesenchymal stem cells derived from the submandibular glands of tdTomato transgenic mice

Transgenic mice that overexpress the red fluorescent protein tdTomato (tdTomato mice) are well suited for use in regenerative medicine studies. Cultured cells from this murine model exhibit strong red fluorescence, enabling real-time in vivo imaging through the body surface of grafted animals. Mesenchymal stem cells (MSCs) have marked potential for use in cell therapy and regenerative medicine; however, the mechanisms that regulate their dynamics in vivo are poorly understood. In the present study, an MSC line was derived from the submandibular gland fibroblasts of tdTomato mice. The fluorescent signal from this cell line was observed in organs throughout the body, as well as in salivary glands. Primary culture cells derived from the submandibular gland were immortalized with SV40 large T antigen (GManSV cells); these cells exhibited increased migratory ability, as compared with those isolated from the sublingual gland. GManSV cells were tdTomato-positive and exhibited spindle-shaped fibroblastic morphology; they also robustly expressed mouse MSC markers: Stem cell antigen-1 (Sca-1), CD44, and CD90. This cell line retained multipotent stem cell characteristics, as evidenced by its ability to differentiate into both osteogenic and adipogenic lineages. These results indicate that Sca-1⁺/CD44⁺/CD90⁺-GManSV cells may be useful for kinetic studies of submandibular gland-derived MSCs in the context of in vitro co-culture with other types of salivary gland-derived cells. These cells may also be used for in vivo imaging studies, in order to identify novel cell therapy and regenerative medicine for the treatment of salivary gland diseases.

Submandibular Gland Transfer for the Prevention of Postradiation Xerostomia in Patients with Head and Neck Cancer: A Systematic Review and Meta-Analysis

<b><i>Background:</i></b> Submandibular gland transfer has been widely used to prevent postradiation xerostomia in head-and-neck cancers. However, there are still some controversies. <b><i>Methods:</i></b> Six databases were searched, data extraction was performed and the risk of bias was assessed by 2 reviewers independently. The meta-analysis was performed using Review Manager, version 5.2. <b><i>Results:</i></b> A total of 7 trials (12 articles) and 369 participants were included. <b><i>Conclusions:</i></b> The present clinical evidence suggests that submandibular gland transfer might be highly effective to prevent postradiation xerostomia in head-and-neck cancers without serious adverse events. However, more randomized controlled trials are still needed to confirm this conclusion.

Adult stem cells and tissue engineering strategies for salivary gland regeneration: a review

Saliva is an important compound produced by the salivary glands and performs numerous functions. Hyposalivation (dry mouth syndrome) is a deleterious condition often resulting from radiotherapy for patients with head and neck cancer, Sjogren's Syndrome, or as a side effect of certain medications. Hyposalivation negatively affects speaking, mastication, and swallowing in afflicted patients, greatly reducing their quality of life. Current treatments for this pathology include modifying lifestyle, synthetic saliva supplementation, and the utilization of salivary gland stimulants and sialagogues. However, many of these treatments do not address the underlying issues and others are pervaded by numerous side effects. In order to address the shortcomings related to current treatment modalities, many groups have diverted their attention to utilizing tissue engineering and regenerative medicine approaches. Tissue engineering is defined as the application of life sciences and materials engineering toward the development of tissue substitutes that are capable of mimicking the structure and function of their natural analogues within the body. The general underlying strategy behind the development of tissue engineered organ substitutes is the utilization of a combination of cells, biomaterials, and biochemical cues intended to recreate the natural organ environment. The purpose of this review is to highlight current bioengineering approaches for salivary gland tissue engineering and the adult stem cell sources used for this purpose. Additionally, future considerations in regard to salivary gland tissue engineering strategies are discussed.

Recombinant AAV9-TLK1B administration ameliorates fractionated radiation-induced xerostomia

Salivary glands are highly susceptible to radiation, and patients with head and neck cancer treated with radiotherapy invariably suffer from its distressing side effect, salivary hypofunction. The reduction in saliva disrupts oral functions, and significantly impairs oral health. Previously, we demonstrated that adenoviral-mediated expression of Tousled-like kinase 1B (TLK1B) in rat submandibular glands preserves salivary function after single-dose ionizing radiation. To achieve long-term transgene expression for protection of salivary gland function against fractionated radiation, this study examines the usefulness of recombinant adeno-associated viral vector for TLK1B delivery. Lactated Ringers or AAV2/9 with either TLK1B or GFP expression cassette were retroductally delivered to rat submandibular salivary glands (10(11) vg/gland), and animals were exposed, or not, to 20 Gy in eight fractions of 2.5 Gy/day. AAV2/9 transduced predominantly the ductal cells, including the convoluted granular tubules of the submandibular glands. Transgene expression after virus delivery could be detected within 5 weeks, and stable gene expression was observed till the end of study. Pilocarpine-stimulated saliva output measured at 8 weeks after completion of radiation demonstrated >10-fold reduction in salivary flow in saline- and AAV2/9-GFP-treated animals compared with the respective nonirradiated groups (90.8% and 92.5% reduction in salivary flow, respectively). Importantly, there was no decrease in stimulated salivary output after irradiation in animals that were pretreated with AAV2/9-TLK1B (121.5% increase in salivary flow; p<0.01). Salivary gland histology was better preserved after irradiation in TLK1B-treated group, though not significantly, compared with control groups. Single preemptive delivery of AAV2/9-TLK1B averts salivary dysfunction resulting from fractionated radiation. Although AAV2/9 transduces mostly the ductal cells of the gland, their protection against radiation assists in preserving submandibular gland function. AAV2/9-TLK1B treatment could prove beneficial in attenuating xerostomia in patients with head and neck cancer undergoing radiotherapy.

Retrograde ductal administration of the adenovirus-mediated NDRG2 gene leads to improved sialaden hypofunction in estrogen-deficient rats

One of the most common oral manifestations of menopause is xerostomia. Oral dryness can profoundly affect quality of life and interfere with basic daily functions, such as chewing, deglutition, and speaking. Although the feeling of oral dryness can be ameliorated after estrogen supplementation, the side effects of estrogen greatly restrict its application. We previously found that N-myc downstream-regulated gene 2 (NDRG2) is involved in estrogen-mediated ion and fluid transport in a cell-based model. In the present study, we used an ovariectomized rat model to mimic xerostomia in menopausal women and constructed two adenovirus vectors bearing NDRG2 to validate their therapeutic potential. Ovariectomized rats exhibited severe sialaden hypofunction, including decreased saliva secretion and ion reabsorption as well as increased water intake. Immunohistochemistry revealed that the expression of NDRG2 and Na(+) reabsorption-related Na(+)/K(+)-ATPase and epithelial sodium channels (EnaC) decreased in ovariectomized rat salivary glands. We further showed that the localized delivery of NDRG2 improved the dysfunction of Na(+) and Cl(-) reabsorption. In addition, the saliva flow rate and water drinking recovered to normal. This study elucidates the mechanism of estrogen deficiency-mediated xerostomia or sialaden hypofunction and provides a promising strategy for therapeutic intervention.

Cost-effectiveness landscape analysis of treatments addressing xerostomia in patients receiving head and neck radiation therapy

Head and neck (H&N) radiation therapy (RT) can induce irreversible damage to the salivary glands thereby causing long-term xerostomia or dry mouth in 68%-85% of the patients. Not only does xerostomia significantly impair patients' quality-of-life (QOL) but it also has important medical sequelae, incurring high medical and dental costs. In this article, we review various measures to assess xerostomia and evaluate current and emerging solutions to address this condition in H&N cancer patients. These solutions typically seek to accomplish 1 of the 4 objectives: (1) to protect the salivary glands during RT, (2) to stimulate the remaining gland function, (3) to treat the symptoms of xerostomia, or (4) to regenerate the salivary glands. For each treatment, we assess its mechanisms of action, efficacy, safety, clinical utilization, and cost. We conclude that intensity-modulated radiation therapy is both the most widely used prevention approach and the most cost-effective existing solution and we highlight novel and promising techniques on the cost-effectiveness landscape.

Efficacy of Pilocarpine and Bromhexine in Improving Radiotherapy-induced Xerostomia

Background and aims. Xerostomia is one of the most common complications of head and neck radiotherapy. The aim of this study was to evaluate and compare the efficacy of pilocarpine and bromhexine in improving radiotherapy-induced xerostomia and its associated symptoms.

Materials and methods. In this single-blind, randomized crossover study, pilocarpine and bromhexine tablets were used by twenty-five patients suffered from xerostomia, with a medical history of head and neck radiotherapy. At step A, the patients were treated with pilocarpine for 2 weeks. In addition, they were asked to take bromhexine for 2 weeks with a one-week washout period. At step B, the inverse process was conducted (first bromhexine, then pilocarpine). Whole resting saliva was collected from patients before and after receiving each medication by precise measurements. Then, efficacy of the two drugs in the treatment of xerostomia and its related oral complications was evaluated using questionnaires by Dichotomous format. The results were statistically analyzed using t-student and Fisher’s exact and chi-squared tests. Statistical significance was set at P<0.05.

Results. The difference between saliva secretion rates before and after medications was not significant for bromhexine users at two steps of the study (P=0.35); however, it was significant for pilocarpine users (P=0.0001). Users of both drugs showed significant differences in improvement of xerostomia, chewing, swallowing, tasting and mouth burning.

Conclusion. Pilocarpine is probably more effective in improving xerostomia and its associated problems compared with bromhexine, although the use of the latter was also shown to ease some of the consequences of radiotherapy in the head and neck region.

Evaluation of a moisturising micro-gel spray for prevention of cell dryness in oral mucosal cells: an in vitro study and evaluation in a clinical setting

A moisturising micro-gel spray for prevention of dryness was compared with commercial products and artificial saliva in vitro and in a clinical setting in patients with cancer. Survival of cultured human gingival epithelial cells was evaluated after treatment with each product for 15 min. A dry test was performed for products giving a 50% survival rate, in which cell survival was measured after drying of cells treated with each product. The survival rates of cells treated with the micro-gel spray and artificial saliva were significantly higher than those of control cells. The micro-gel spray was then evaluated for 1 week in patients with symptoms of dry mouth caused by cancer treatment. There was significant improvement of these symptoms at night and on awakening and of subjective symptoms of decreased salivary volume (P < 0.05). Mean visual analogue scale scores also significantly decreased (P < 0.01). These data suggest that evaluation of moisturising products for dryness prevention can be performed in cultured cells, since products that performed well in vitro also showed good efficacy for symptoms of dry mouth. The micro-gel spray was particularly effective for relieving symptoms of dry mouth in patients with cancer.

Group acupuncture to relieve radiation induced xerostomia: a feasibility study

BACKGROUND

a distressing complication of radiotherapy treatment for head and neck cancer is xerostomia (chronic oral dryness). Xerostomia is difficult to treat conventionally but there are reports that acupuncture can help. We conducted a feasibility study to examine the acceptability of a standardised group acupuncture technique and adherence to group sessions, together with acceptability of the objective and subjective measurements of xerostomia.

METHODS

12 males with established radiation induced xerostomia were treated in three groups of four. Each received eight weekly sessions of acupuncture using four bilateral acupuncture points (Salivary Gland 2; Modified Point Zero; Shen Men and one point in the distal radial aspect of each index finger (LI1)). Sialometry and quality of life assessments were performed at baseline and at the end of treatment. A semi-structured interview was conducted a week after completing the intervention.

RESULTS

adherence to and acceptability of the treatment and assessments was 100%. There were objective increases in the amounts of saliva produced for 6/12 patients post intervention and the majority also reported subjective improvements. Mean quality of life scores for domains related to salivation and xerostomia also showed improvement. At baseline 92% (11/12) patients reported experiencing a dry mouth "quite a bit/very much" as compared to 42% (5/12) after the treatment. Qualitative data revealed that the patients enjoyed the sessions.

CONCLUSION

the pilot study shows that a standardised group technique is deliverable and effective. The tools for objective and subjective assessment are appropriate and acceptable. Further examination in a randomised trial is now warranted.

Protective effects of polysaccharides and polyhydric alcohols in a dry mouth model in cultured cells

PURPOSE

The goal of the study was to investigate the effects of 21 polysaccharides and 12 polyhydric alcohols on inhibition of dryness in oral mucosal epithelial cells in vitro. All the tested compounds are currently used in oral products.

METHODS

Human gingival epithelial Ca9-22 cells were incubated in 96-well plates until the cells reached confluence. After removal of the culture medium, the cells were incubated with a solution containing one of 21 polysaccharides (seven semisynthetic and 14 natural polysaccharides) or 12 polyhydric alcohols for 15 min (short-term treatment). After removal of the sample solution, the cells were dried at 25°C and 30% humidity, and cell viability was measured to determine the effect of each compound on prevention of cell death due to drying. The effects of the polyhydric alcohols were also examined for 3 days (long-term treatment).

RESULTS

The semisynthetic polysaccharides ethylcellulose (EC), methylcellulose (MC), and hydroxypropylmethylcellulose (HPMC) and the natural polysaccharides xanthan and gellan gum significantly inhibited cell death due to drying. Hydroxypropylcellulose increased cell death under these conditions. Of the polyhydric alcohols, long-term treatment with glycosyltrehalose significantly inhibited cell death due to drying, but short-term treatment with glycosyltrehalose did not do so. Long-term treatment had an effect on cell proliferation that appeared to differ from the effect of short-term treatment.

CONCLUSIONS

Short-term treatment with EC, MC, HPMC, xanthan gum, and gellan gum and long-term treatment with glycosyltrehalose showed significant inhibition of cell death due to drying. These materials might have protective effects against dry mouth.

Cevimeline-induced monophasic salivation from the mouse submandibular gland: decreased Na+ content in saliva results from specific and early activation of Na+/H+ exchange

Cevimeline and pilocarpine are muscarinic agonists used clinically to treat dry mouth. In this study, we explored fluid secretion from mouse submandibular glands to determine the mechanism of cevimeline, pilocarpine, and an experimentally used agent carbachol. Cevimeline evoked almost the same amount of secretion at concentrations from 30 μM to 1 mM. Pilocarpine also induced secretion at a concentration as low as 1 μM and was the most powerful secretagogue at 10 μM. Secretion was induced by carbachol at 0.1 μM, with maximum secretion at 1.0 μM. Cevimeline induced monophasic secretion at all concentrations tested, whereas higher concentrations of pilocarpine and carbachol induced secretion with variable kinetics, i.e., an initial transient high flow rate, followed by decreased secretion after 2 to 3 min. In the presence of an epithelial Na(+) channel blocker, amiloride, neither carbachol nor pilocarpine affected the Na(+) level of secreted saliva; however, it significantly increased the Na(+) content of cevimeline-induced saliva. The intracellular Ca(2+) response of acinar cells was almost identical among all three agents, although recovery after drug removal was slower for cevimeline and pilocarpine. A profound decrease in intracellular pH was observed during pilocarpine and carbachol treatment, whereas intracellular acidification induced by cevimeline was only seen in the presence of a Na(+)/H(+) exchange inhibitor. When external HCO(3)(-) was removed, cevimeline-induced saliva significantly decreased. These findings suggest that cevimeline specifically activates Na(+)/H(+) exchange and may promote Na(+) reabsorption by stabilizing epithelial sodium channel activity.

Tramadol-induced oral dryness and pilocarpine treatment: effects on total protein and IgA

Pilocarpine induces a profuse flow of saliva, and it may re-establish saliva production in cases of drug-induced oral dryness. The aim of the study (a sub-study to the previous trial investigating the pilocarpine fluid effects in individuals suffering from drug-induced dry mouth) was to search for saliva quality changes induced by the treatments. Sixty-five individuals were enrolled in a randomized, double-blind, placebo-controlled trial. The subjects received tramadol to induce oral dryness. Secretion rate was measured before and after tramadol, and then after pilocarpine, placebo, or no treatment. All saliva was analyzed for its protein and IgA content in the pilocarpine (n=15) and placebo groups (n=12). At baseline, the flow of saliva was 0.47±0.05ml/min, the protein output 0.17±0.2mg/min and the IgA output 0.022±0.002mg/min. After tramadol treatment (50mg 3×/day over two days), the flow was reduced by 64%, protein output by 52% and the IgA output by 38%. While placebo treatment did not affect any of the variables, the flow was 120%, the protein output 193% and the IgA output 83% of the baseline characteristics after pilocarpine treatment (5mg). Thus, the pilocarpine-induced increase in the flow rate in the state of tramadol-induced oral dryness results in saliva with a well preserved protein concentration but with a decrease in IgA concentration. However, compared to baseline, there was neither a decrease in output nor in concentration of IgA.

Xerostomia in head and neck malignancy

Xerostomia (dry mouth) as a consequence of treatment of head and neck malignancy is almost always due to radiotherapy. The resultant salivary gland dysfunction can adversely affect oral and systemic health as well as lessen quality of life. While the present management of radiotherapy-associated salivary dysfunction is challenging there have been striking advances in preventative strategies and a number of possible treatment options may be over the near horizon.

Oral and dental health care of oral cancer patients: hyposalivation, caries and infections

Oral cancer and its treatment can cause a variety of problems to patients, also as regards maintaining their daily oral hygiene. Surgery mutilates tissues which may hamper cleaning the teeth and mucosal surfaces. The patient may have complicated reconstructive structures that also need continuous attention. Radiotherapy-induced hyposalivation further complicates the situation and decreases the quality of life. Consequently, dental caries, mucosal diseases such as candidosis and sialadenitis become problematic to treat. Hence every effort should be focused on prevention. In caries prevention intensified fluoride therapy together with dietary counseling is needed. Oral cancer patients also need to be frequently referred to dental hygienists for professional cleaning. Drinking enough daily and moisturizing mucosal surfaces with commercial dry-mouth products, vegetable oils, milk products and respective topical agents need to be individually recommended. In addition, patients with severe dry mouth cases may also benefit from the prescription of pilocarpine tablets. In oral candidosis, the microbiological diagnosis must be confirmed before administration of antifungal drugs in order to avoid the selection pressure to resistant strains.

The diagnostic suitability of a xerostomia questionnaire and the association between xerostomia, hyposalivation and medication use in a group of nursing home residents

The study objective was to explore the diagnostic suitability of the Xerostomia Inventory and the association between xerostomia, hyposalivation and medication use in a group of nursing home residents. A cross-sectional study was carried out in 50 physically impaired nursing home residents (20 men) with a mean age of 78.1 years (range, 53–98) in The Netherlands. The Xerostomia Inventory-Dutch version was completed for all residents and the data were subjected to exploratory factor analysis to determine the diagnostic suitability. Residents’ data on xerostomia, whole saliva secretion rates and hyposalivation-related medications used were collected and statistically analyzed. The diagnostic suitability of the Xerostomia Inventory-Dutch version appeared restricted. The prevalence of xerostomia was 52%, without gender and age difference. The prevalence of hyposalivation was 24% for resting, 60% for chewing-stimulated and 18% for acid-stimulated whole saliva. All whole saliva secretion rates were significantly lower in women than in men and in older than in younger residents. Forty-four percent of all medications used were hyposalivation-related and women used significantly more medications than men. Xerostomia was significantly negatively correlated with the resting whole saliva secretion rate. The number of hyposalivation-related medications used was not significantly correlated with the various whole saliva secretion rates. In nursing home residents, xerostomia, hyposalivation and using hyposalivation-related medications seem common and partially associated features.