Treatment of xerostomia with the bile secretion-stimulating drug anethole trithione: a clinical trial

Proposed mechanisms of action of herbal drugs and their biologically active constituents in the treatment of coughs: an overview

Various medicinal plants find their use in cough treatment, based on traditions and long-term experience. Pharmacological principles of their action, however, are much less known. Herbal drugs usually contain a mixture of potentially active compounds, which can manifest diverse effects. Expectorant or antitussive effects, which can be accompanied by others, such as anti-inflammatory or antibacterial, are probably the most important in the treatment of coughs. The aim of this review is to summarize the current state of knowledge of the effects of medicinal plants or their constituents on cough, based on reliable pharmacological studies. First, a comprehensive description of each effect is provided in order to explain the possible mechanism of action in detail. Next, the results related to individual plants and substances are summarized and critically discussed based on pharmacological in vivo and in vitro investigation.

H2S Donors and Their Use in Medicinal Chemistry

Hydrogen sulfide (H2S) is a ubiquitous gaseous signaling molecule that has an important role in many physiological and pathological processes in mammalian tissues, with the same importance as two others endogenous gasotransmitters such as NO (nitric oxide) and CO (carbon monoxide). Endogenous H2S is involved in a broad gamut of processes in mammalian tissues including inflammation, vascular tone, hypertension, gastric mucosal integrity, neuromodulation, and defense mechanisms against viral infections as well as SARS-CoV-2 infection. These results suggest that the modulation of H2S levels has a potential therapeutic value. Consequently, synthetic H2S-releasing agents represent not only important research tools, but also potent therapeutic agents. This review has been designed in order to summarize the currently available H2S donors; furthermore, herein we discuss their preparation, the H2S-releasing mechanisms, and their -biological applications.

Artificial Saliva for Therapeutic Management of Xerostomia: A Narrative Review

In clinical practice, xerostomia or oral dryness is a chronic disease condition encountered by most dentists and dental hygienists, which often causes a negative impact on the oral health-related quality of life of the affected individual. Xerostomia is caused due to salivary gland dysfunction. It is related to reduced salivary secretion or the absence of saliva flow, more frequently, exhibits qualitative changes in saliva proteins and immunoglobulin concentrations that arise due to salivary gland dysfunction. This condition causes discomfort and interferes with normal oral activities, and affected individuals are at high caries risk. There are several options for treatment and symptom management: salivary stimulants, topical agents, saliva substitutes, and systemic sialogogues. This review explores the current status of therapeutic management of patients affected by xerostomia and hyposalivation using artificial saliva.

A Randomized, Double-Blind, Placebo-Controlled, Cross-Over Study to Evaluate the Efficacy of AqualiefTM Mucoadhesive Tablets in Head and Neck Cancer Patients Who Developed Radiation-Induced Xerostomia

Xerostomia, the subjective complaint of dry mouth, is caused by therapeutic interventions or diseases. Nowadays, radiotherapy (RT) in patients with head and neck cancer (HNC) stands out as one of the most important causes of xerostomia. Currently available therapies for the treatment of xerostomia are still less than optimal and xerostomia still represents an unmet clinical need. In this article, we present the results of a prospective clinical study with a new product, Aqualief^TM, in patients treated with curative RT with or without chemotherapy for HNC. Aqualief^TM is based on two main ingredients, carnosine and karkadé, which have acid buffering and antioxidant properties. The study was performed on 30 patients, with 4 of the patients being lost during the study period. Each patient received randomly one of the two treatments, Aqualief^TM or placebo, for 8 days. After a 10-day wash-out period, each patient received the other treatment for a further 8 days. The results show that Aqualief^TM stimulated salivation in these patients and reduced the pH drop that was observed in an equivalent placebo-treated population of patients. Moreover, no serious, treatment-related adverse events were observed. Aqualief^TM has shown positive results, although with limitations due to unsuccessful trial accrual. Therefore, it may be further investigated as a tool for the treatment of RT-related xerostomia.

Trends in H2S-Donors Chemistry and Their Effects in Cardiovascular Diseases

Hydrogen sulfide (H₂S) is an endogenous gasotransmitter recently emerged as an important regulatory mediator of numerous human cell functions in health and in disease. In fact, much evidence has suggested that hydrogen sulfide plays a significant role in many physio-pathological processes, such as inflammation, oxidation, neurophysiology, ion channels regulation, cardiovascular protection, endocrine regulation, and tumor progression. Considering the plethora of physiological effects of this gasotransmitter, the protective role of H₂S donors in different disease models has been extensively studied. Based on the growing interest in H₂S-releasing compounds and their importance as tools for biological and pharmacological studies, this review is an exploration of currently available H₂S donors, classifying them by the H₂S-releasing-triggered mechanism and highlighting those potentially useful as promising drugs in the treatment of cardiovascular diseases.

The evolving landscape for cellular nitric oxide and hydrogen sulfide delivery systems: A new era of customized medications

Nitric oxide (NO) and hydrogen sulfide (H2S) are industrial toxins or pollutants; however, both are produced endogenously and have important biological roles in most mammalian tissues. The recognition that these gasotransmitters have a role in physiological and pathophysiological processes has presented opportunities to harness their intracellular effects either through inhibition of their production; or more commonly, through inducing their levels and or delivering them by various modalities. In this review article, we have focused on an array of NO and H2S donors, their hybrids with other established classes of drugs, and the various engineered delivery platforms such a fibers, polymers, nanoparticles, hydrogels, and others. In each case, we have reviewed the rationale for their development.

The Benefits of Macromolecular/Supramolecular Approaches in Hydrogen Sulfide Delivery: A Review of Polymeric and Self-Assembled Hydrogen Sulfide Donors

Significance: Cell homeostasis and redox balance are regulated in part by hydrogen sulfide (H2S), a gaseous signaling molecule known as a gasotransmitter. Given its biological roles, H2S has promising therapeutic potential, but controlled delivery of this reactive and hazardous gas is challenging due to its promiscuity, rapid diffusivity, and toxicity at high doses. Macromolecular and supramolecular drug delivery systems are vital for the effective delivery of many active pharmaceutical ingredients, and H2S stands to benefit greatly from the tunable physical, chemical, and pharmacokinetic properties of polymeric and/or self-assembled drug delivery systems. Recent Advances: Several types of H2S-releasing macro- and supramolecular materials have been developed in the past 5 years, and the field is expanding quickly. Slow-releasing polymers, polymer assemblies, polymer nano- and microparticles, and self-assembled hydrogels have enabled triggered, sustained, and/or localized H2S delivery, and many of these materials are more potent in biological assays than analogous small-molecule H2S donors. Critical Issues: H2S plays a role in a number of (patho)physiological processes, including redox balance, ion channel regulation, modulation of inducible nitric oxide synthase, angiogenesis, blood pressure regulation, and more. Chemical tools designed to (i) deliver H2S to study these processes, and (ii) exploit H2S signaling pathways for treatment of diseases require control over the timing, rate, duration, and location of release. Future Directions: Development of new material approaches for H2S delivery that enable long-term, triggered, localized, and/or targeted delivery of the gas will enable greater understanding of this vital signaling molecule and eventually expedite its clinical application.

An old medicine as a new drug to prevent mitochondrial complex I from producing oxygen radicals

Findings

Here, we demonstrate that OP2113 (5-(4-Methoxyphenyl)-3H-1,2-dithiole-3-thione, CAS 532-11-6), synthesized and used as a drug since 1696, does not act as an unspecific antioxidant molecule (i.e., as a radical scavenger) but unexpectedly decreases mitochondrial reactive oxygen species (ROS/H₂O₂) production by acting as a specific inhibitor of ROS production at the I_Q site of complex I of the mitochondrial respiratory chain. Studies performed on isolated rat heart mitochondria also showed that OP2113 does not affect oxidative phosphorylation driven by complex I or complex II substrates. We assessed the effect of OP2113 on an infarct model of ex vivo rat heart in which mitochondrial ROS production is highly involved and showed that OP2113 protects heart tissue as well as the recovery of heart contractile activity.

Conclusion / Significance

This work represents the first demonstration of a drug authorized for use in humans that can prevent mitochondria from producing ROS/H₂O₂. OP2113 therefore appears to be a member of the new class of mitochondrial ROS blockers (S1QELs) and could protect mitochondrial function in numerous diseases in which ROS-induced mitochondrial dysfunction occurs. These applications include but are not limited to aging, Parkinson’s and Alzheimer's diseases, cardiac atrial fibrillation, and ischemia-reperfusion injury.

A review of hydrogen sulfide (H2S) donors: Chemistry and potential therapeutic applications

Hydrogen sulfide (H2S) is a ubiquitous small gaseous signaling molecule, playing an important role in many physiological processes and joining nitric oxide and carbon monoxide in the group of signaling agents termed gasotransmitters. Endogenous concentrations of H2S are generally low, making it difficult to discern precise biological functions. As such, probing the physiological roles of H2S is aided by exogenous delivery of the gas in cell and animal studies. This need for an exogenous source of H2S provides a unique challenge for chemists to develop chemical tools that facilitate the study of H2S under biological conditions. Compounds that degrade in response to a specific trigger to release H2S, termed H2S donors, include a wide variety of functional groups and delivery systems, some of which mimic the tightly controlled endogenous production in response to specific, biologically relevant conditions. This review examines a variety of H2S donor systems classified by their H2S-releasing trigger as well as their H2S release profiles, byproducts, and potential therapeutic applications.

Xerostomia induced by radiotherapy: an overview of the physiopathology, clinical evidence, and management of the oral damage

BACKGROUND

The irradiation of head and neck cancer (HNC) often causes damage to the salivary glands. The resulting salivary gland hypofunction and xerostomia seriously reduce the patient's quality of life.

PURPOSE

To analyze the literature of actual management strategies for radiation-induced hypofunction and xerostomia in HNC patients.

METHODS

MEDLINE/PubMed and the Cochrane Library databases were electronically evaluated for articles published from January 1, 1970, to June 30, 2013. Two reviewers independently screened and included papers according to the predefined selection criteria.

RESULTS

Sixty-one articles met the inclusion criteria. The systematic review of the literature suggests that the most suitable methods for managing the clinical and pathophysiological consequences of HNC radiotherapy might be the pharmacological approach, for example, through the use of cholinergic agonists when residual secretory capacity is still present, and the use of salivary substitutes. In addition, a modified diet and the patient's motivation to enhance oral hygiene can lead to a significant improvement.

CONCLUSION

Radiation-induced xerostomia could be considered a multifactorial disease. It could depend on the type of cancer treatment and the cumulative radiation dose to the gland tissue. A preventive approach and the correct treatment of the particular radiotherapeutic patient can help to improve the condition of xerostomia.

Diagnosis and management of xerostomia and hyposalivation

Xerostomia, the subjective complaint of dry mouth, and hyposalivation remain a significant burden for many individuals. Diagnosis of xerostomia and salivary gland hypofunction is dependent upon a careful and detailed history and thorough oral examination. There exist many options for treatment and symptom management: salivary stimulants, topical agents, saliva substitutes, and systemic sialogogues. The aim of this review is to investigate the current state of knowledge on management and treatment of patients affected by xerostomia and/or hyposalivation.

Dithiolethione compounds inhibit Akt signaling in human breast and lung cancer cells by increasing PP2A activity

The chemo-preventative effects of dithiolethione compounds are attributed to their activation of anti-oxidant response elements (ARE) by reacting with the Nrf2/Keap1 protein complex. In this study, we demonstrate anti-proliferative effects of the dithiolethione compound ACS-1 in human cancer cell lines (A549 and MDA-MB-231) by increasing the activity of the tumor suppressor PP2A. ACS-1 inhibited EGF-induced cellular proliferation in a concentration and time-dependent manner. Akt activation, as determined by serine-473 phosphorylation, was inhibited by ACS-1 in cells stimulated with either EGF or fibronectin. Furthermore, ACS-1 inhibited mTOR signaling and decreased c-myc protein levels. ACS-1 did not proximally alter EGFR or integrin signaling, but caused a concentration-dependent increase in PP2A activity. The effect of ACS-1 on Akt activation was not observed in the presence of the PP2A inhibitor okadaic acid. ACS-1 effects on PP2A activity were independent of ARE activation and cAMP formation. In addition to ACS-1, other dithiolethione compounds showed similar effects in reducing Akt activation, suggesting that this class of compounds may have other effects beyond chemoprevention.

HPLC determination of anethole trithione and its application to pharmacokinetics in rabbits

To evaluate the relative bioavailability of anethole trithione (ATT) from self-microemulsifying drug delivery system (SMEDDS) and tablet, a sensitive, accurate and reliable liquid chromatography method was developed and validated to determine ATT in rabbit plasma. Chromatographic separation was performed on a Diamonsil C18 column by using a mixture of methanol-water (90:10, v/v) delivered at a flow rate of 1.0 ml/min. The wavelength was set at 348 nm and mifepristone was used as the internal standard. A linear relationship for ATT was found in the range of 0.5-32 ng/ml. The mean extraction recoveries of ATT determined over three concentrations were 84.7+/-5.8, 92.3+/-3.4 and 89.9+/-5.1%. After administration of SMEDDS and tablets to rabbits, significant differences were found in main pharmacokinetic parameters of Tmax, Cmax and AUC(0-infinity) between these two formulations, and a 2.5-fold enhancement of relative bioavailability of ATT was observed from the SMEDDS compared with tablets.

L’anethole dithiolethione : un agent cytoprotecteur contre la ténotoxicité induite par les fluoroquinolones

Tendinopathy and tendon rupture are the adverse effects observed with fluoroquinolone antibiotics in old patients. The aim of this study was to investigate the effect of anethole dithiolethione (5-[p-methoxyphenyl]3H-1,2-dithiole-3-thione) on the oxidative stress induced by three fluoroquinolones (pefloxacin, ofloxacin, ciprofloxacin) incubated with rabbit tenocyte cell line. Anethole dithiolethione is a well known antioxidant and glutathione inducer. Anethole dithiolethione is widely used in human therapy for its choleretic, sialogogic properties and recently proposed as cytoprotective agent in lung precancerous lesions prevention in smokers. In this purpose, protection against oxidative stress induced by fluoroquinolones has been assessed using cytofluorimetric probes to quantify cytotoxicity and reactive oxygen species production. Fluorescence signal was quantified in 96-well microplates, using cold light cytofluorometer. Significant reactive oxygen species production was detected after 45 minutes for all fluoroquinolones tested. Anethole dithiolethione has been evaluated on this parameter. Anethole dithiolethione significantly (*: P<0.05) reduces and normalizes reactive oxygen species induced by fluoroquinolones. So, anethole dithiolethione (Sulfarlem), well known for its antioxidant and glutathione inducing properties, good tissue diffusion and good tolerance in humans, could be beneficially associated to fluoroquinolones, and be proposed as a therapeutic adjuvant to prevent oxidative stress and tendinous adverse effects induced by xenobiotics and more precisely by fluoroquinolones.

Salivary Enhancement Therapies

When salivary output is reduced chronically to a significant extent, there is a marked increase in dental caries. As the role of saliva in protection of the oral hard tissue is well recognized, there have long been efforts to enhance salivary function in conditions with associated secretory hypofunction. The rationale is that by stimulating salivary output, caries and other oral complications will be reduced or eliminated. The most widely used method for increasing salivary function is a combination of masticatory and gustatory stimulation. A large number of systemic agents have also been proposed as secretagogues, but only a few have shown consistent salivary enhancing properties in well-designed, controlled trials. Pilocarpine has been shown to improve symptoms of oral dryness and to increase salivary output in patients with Sjögren's syndrome and postradiation xerostomia. Recently, cevimeline has shown significant salivary enhancement in Sjögren's syndrome. Pilocarpine and cevimeline have a similar mechanism of action, side effect profile and duration of activity. No secretagogues have been linked directly in clinical trials to either caries prevention or a reduction in the existing caries rate of salivary dysfunction patients. Improved secretagogues are needed, with fewer side effects, increased duration of activity and greater potency. Future research directions include gene therapeutic approaches to direct salivary growth and differentiation or modify remaining tissues to promote secretion, creation of a biocompatible artificial salivary gland and salivary transplantation. With improved secretagogues, the effects of conditions that result in reduced salivary function and increased caries will be ameliorated.

Influence of parotid-sparing radiotherapy on xerostomia in head and neck cancer patients

Radiotherapy (RT) for head and neck cancers causes permanent salivary gland dysfunction (SGD) and xerostomia. We have previously demonstrated the effectiveness of parotid-sparing RT on salivary function. The aim of this was to characterize the relationship between radiation dosages to parotid glands, SGD, xerostomia, and impaired quality of life (QOL). Ninety-three patients received unilateral (n=38) and bilateral (n=44) neck RT with parotid-sparing techniques, or standard three-field technique RT (n=11). Unstimulated and stimulated parotid saliva was collected pre-RT and 1 year post-RT. Assessment of QOL and xerostomia was conducted with three questionnaires. The results demonstrated that reduced radiation dosages to parotid glands were strongly associated with percentage of baseline parotid flow rates measured at 1 year post-RT. Unilateral and bilateral neck RT with parotid-sparing techniques were successful in preserving salivary output, compared to standard three beam RT techniques. Lower radiation dose to contralateral parotid glands was associated with greater percentage of baseline salivary flow rates at 1 year post-RT, fewer xerostomic complaints, and an enhanced QOL.

An update of the etiology and management of xerostomia

Salivary gland disease gives rise to salivary gland enlargement, pain, and prolonged xerostomia (dry mouth). Xerostomia is the most common long-standing problem for the majority of affected patients. There are many causes of dry mouth, with long-standing xerostomia being a particular problem in Sjögren's syndrome and after radiation to the head and neck region. Xerostomia is usually managed with saliva substitutes, but a large number of potential systemic therapies of long-standing xerostomia now exist. Some-particularly immunosuppressants-are of fundamental interest for the potential reduction of gland damage in Sjögren's syndrome but as yet are of limited clinical usefulness. Others, particularly pilocarpine and cevimeline, are, or have the potential to be, clinically useful in stimulating salivation by virtue of their action on cholinergic receptors.

Sjogren's syndrome: evolving therapies

Sjogren's syndrome (keratoconjunctivis sicca) is a relatively common disorder with incidence of approximately 0.5% of adult women. It has both local (ocular and oral) features as well as systemic manifestations. There has been recent FDA approval of agents to stimulate salivation (pilocarpine and cevimeline) and studies are in progress to determine their role in the treatment of dry eye. New therapies are in clinical trials for ocular manifestations with the most interest focused on topical cyclosporin A and purinogenic receptor agonists. In oral therapy, topical human interferon has reported encouraging results in short-term studies. However, the high placebo response (probably reflecting the beneficial response of mechanical stimulation of the buccal mucosa by the lozenge) and the response to much cheaper therapies (such as acid maltose lozenges) may offer safer and cheaper alternatives. For systemic disease, there is interest in tumour necrosis factor inhibitors. However, the cost-effectiveness and safety of biological agents needs longer term follow up, as they appear much less dramatic in their effect on systemic lupus erythematosus or Sjogren's syndrome than in rheumatoid arthritis.

Treatment of xerostomia: a systematic review of therapeutic trials

The results of the present systematic review of randomized controlled trials published in peer-reviewed journals demonstrate the presence of a wide variety of biases and the weakness of the existing literature of xerostomia treatment. The report of statistically significant efficacy on an outcome measure is only meaningful in the setting of a well-controlled, appropriately designed clinical trial. This points to the importance of evaluating the quality of the clinical trial closely when deciding if study results are applicable to a specific patient population. Future studies in the management of xerostomia will require an increased effort on the part of investigators to eliminate easily recognized flaws during the planning stages of a clinical trial. Minimizing bias in clinical studies will allow for easier interpretation and comparisons of different studies. Better clinical trial design is vital to provide maximal confidence in the efficacy of xerostomia interventions.

Salivary gland dysfunction: a review of systemic therapies

Xerostomia may result from salivary dysfunction secondary to a variety of conditions, including medications, autoimmune disease, and tumoricidal therapy. As the geriatric population increases, the incidence of xerostomia will increase and the oral manifestations will continue to be a challenge to the clinician. Common oral manifestations resulting from decreased salivary flow include increased dental caries, fungal infections, and dysphagia. Treatment for salivary gland dysfunction is currently limited because of a lack of controlled clinical trials. Medications that have been studied in clinical trials are emphasized in this article. The aim of this article is to briefly review salivary gland physiology and to summarize the suggested systemic treatment modalities for xerostomia that emphasize controlled clinical trials.

[Radiation-induced cataract: physiopathologic, radiobiologic and clinical aspects]

Cataractogenesis is a widely reported late effect of irradiated crystalline lens. In this review the authors discussed the different aspects of radiation cataract pathogenesis, and the different mechanisms involved in the lens opacification, particularly the epithelium modifications such as epithelial cell death. The authors also reported the influence of radiation exposure on cataract formation following total body irradiation (TBI) and autologous or allogeneic bone marrow transplantation for hematologic malignancies. Moreover, the radiobiological parameters are not studied for the crystalline lens of human. We applied for the first time the linear-quadratic (LQ) and biological effective dose (BED) concept to TBI data. The calculated value of alpha/beta of 1 Gy is in the range of the values reported for the other late responding tissues. The other risk factors for cataract development after TBI such as age, gender, central nervous system boost, long-term steroid therapy and heparin administration are discussed. In terms of cataract or sicca syndrome prevention, numerous compounds have been successfully tested in experimental models or used for the prevention of radiation-induced xerostomia in patients treated for head and neck cancer. However, none of them has been clinically evaluated for ocular radiation late effects prevention. In this report the authors discussed some of the radioprotectors potentially interesting for radiation-induced cataract or sicca syndrome prevention.

Candidiasis may induce glossodynia without objective manifestation

BACKGROUND

The causes of glossodynia in the absence of objective abnormalities range widely and differential diagnosis of glossodynia is very difficult.

METHODS

Based on the examination results of peripheral blood, stimulated and nonstimulated salivary flow rate (SFR), glossal pain threshold, and C. albicans cell culture and the response to treatment, we identified the cause of vague pain of the tongue in 98 patients who lacked objective findings and identified candidiasis as the cause of glossodynia in 26 patients.

RESULTS

These patients revealed hyposalivation and decreased glossal pain thresholds and C. albicans cell overgrowth. Pain thresholds in the painful portion (54.6+/-2.9 degrees C) were significantly decreased compared with those in the painless portion (57.7+/-3.4 degrees C) (P < 0.05) and the pain thresholds were largely increased after treatment (57.2+/-1.6 degrees C). Nonstimulated SFR before treatment was lower than that of age- and gender-matched healthy people, although stimulated SFR was decreased only slightly. C. albicans cell overgrowth was detected by the number of C. albicans colonies that formed in Sabouraud's agar plate (539.3+/-198.4/dish). After the subsidence of glossal pain by mouth washing with a 3% amphotericin B solution, the C. albicans colonies were decreased to 31.5+/-19.3/dish, which was almost same as the control level, 14.1+/-8.4/dish.

CONCLUSION

These results indicate that candidiasis in conjunction with hyposalivation may induce pain in the tongue without manifestation of objective abnormalities.