β-Adrenergic signaling induces Notch-mediated salivary gland progenitor cell control

Treatment strategies for clozapine-induced sialorrhea in France: A systematic review

BACKGROUND

Clozapine-induced hypersialorrhoea (or hypersalivation) is a common side effect, and at present there is no therapeutic strategy with a validated indication to treat it. The corrective strategies proposed in the scientific literature have varying degrees of validity. As a result, it is important to regularly update the available data and to make proposals that are in line with the specialties available in each country.

MATERIAL AND METHODS

A systematic review of the literature respecting PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) statements was carried out using the PubMed, Embase and Cochrane databases with the keywords "Clozapine", "induced", "hypersalivation" or "sialorrhea". Only articles dealing with substances marketed in France and written in French or English were selected.

RESULTS

64 articles were included in this review. The various strategies identified corresponded mainly to treatments with regulatory actions on the cholinergic, noradrenergic and dopaminergic neurotransmission systems. This selection of drug strategies available in France for clozapine-induced hypersalivation identified 17 substances.

DISCUSSION AND CONCLUSION

The level of evidence concerning treatments for clozapine-induced hypersialorrhoea remains limited. As a first option, and if clinically feasible (benefit-risk ratio), a cautious, gradual reduction in dosage is preferred. If this fails, local anticholinergic treatment may be initiated and evaluated following pharmaco-practical recommendations based on the drugs available in France and their level of evidence.

A morphological post mortem profile in minor salivary glands changes in females

Women experience several systemic changes over all stages of life, many due to hormonal fluctuations. The sensation of dry mouth is the most common oral clinical symptom in women from climacteric period onwards, suggesting that sex hormones are important in maintaining salivary glands and oral homeostasis. Although the oral cavity is not conventional considered a target tissue for oestrogen, the extent to which salivary glands morphology and function are impacted by ageing and hormonal variations remain unknown. Due to the clinical demand for understanding oral changes related to the ageing process, this study aimed to portray the glandular morphological aspects in female during the different stages of life. To achieve this, 85 post-mortem specimens of labial minor salivary glands were obtained from females; they were distributed into three groups: group I (reproductive phase: up to 44 years, n = 18); group II (climateric phase: 45-55 years, n = 21) and group III (post-menopausal phase: over 56 years, n = 46). The most significant changes observed included degenerative parenchymal aspects including the replacement of parenchymal structures by fibrous tissue, inflammatory infiltrate as well as vascular and endothelial changes. Ageing was associated with acinar serous metaplasia (p = 0.011), acinar fibrosis (p = 0.042) and ductal ectasia (p = 0.003). The process of acinar atrophy was observed in all groups, with an increase in severity in group III. These degenerative aspects appear to be age-dependent.

Duct ligation/de-ligation model: exploring mechanisms for salivary gland injury and regeneration

Sialadenitis and sialadenitis-induced sialopathy are typically caused by obstruction of the salivary gland ducts. Atrophy of the salivary glands in experimental animals caused by duct ligation exhibits a histopathology similar to that of salivary gland sialadenitis. Therefore, a variety of duct ligation/de-ligation models have been commonly employed to study salivary gland injury and regeneration. Duct ligation is mainly characterised by apoptosis and activation of different signaling pathways in parenchymal cells, which eventually leads to gland atrophy and progressive dysfunction. By contrast, duct de-ligation can initiate the recovery of gland structure and function by regenerating the secretory tissue. This review summarizes the animal duct ligation/de-ligation models that have been used for the examination of pathological fundamentals in salivary disorders, in order to unravel the pathological changes and underlying mechanisms involved in salivary gland injury and regeneration. These experimental models have contributed to developing effective and curative strategies for gland dysfunction and providing plausible solutions for overcoming salivary disorders.

Distinct regulatory networks control toxin gene expression in elapid and viperid snakes

BACKGROUND

Venom systems are ideal models to study genetic regulatory mechanisms that underpin evolutionary novelty. Snake venom glands are thought to share a common origin, but there are major distinctions between venom toxins from the medically significant snake families Elapidae and Viperidae, and toxin gene regulatory investigations in elapid snakes have been limited. Here, we used high-throughput RNA-sequencing to profile gene expression and microRNAs between active (milked) and resting (unmilked) venom glands in an elapid (Eastern Brown Snake, Pseudonaja textilis), in addition to comparative genomics, to identify cis- and trans-acting regulation of venom production in an elapid in comparison to viperids (Crotalus viridis and C. tigris).

RESULTS

Although there is conservation in high-level mechanistic pathways regulating venom production (unfolded protein response, Notch signaling and cholesterol homeostasis), there are differences in the regulation of histone methylation enzymes, transcription factors, and microRNAs in venom glands from these two snake families. Histone methyltransferases and transcription factor (TF) specificity protein 1 (Sp1) were highly upregulated in the milked elapid venom gland in comparison to the viperids, whereas nuclear factor I (NFI) TFs were upregulated after viperid venom milking. Sp1 and NFI cis-regulatory elements were common to toxin gene promoter regions, but many unique elements were also present between elapid and viperid toxins. The presence of Sp1 binding sites across multiple elapid toxin gene promoter regions that have been experimentally determined to regulate expression, in addition to upregulation of Sp1 after venom milking, suggests this transcription factor is involved in elapid toxin expression. microRNA profiles were distinctive between milked and unmilked venom glands for both snake families, and microRNAs were predicted to target a diversity of toxin transcripts in the elapid P. textilis venom gland, but only snake venom metalloproteinase transcripts in the viperid C. viridis venom gland. These results suggest differences in toxin gene posttranscriptional regulation between the elapid P. textilis and viperid C. viridis.

CONCLUSIONS

Our comparative transcriptomic and genomic analyses between toxin genes and isoforms in elapid and viperid snakes suggests independent toxin regulation between these two snake families, demonstrating multiple different regulatory mechanisms underpin a venomous phenotype.

Systematic review with meta-analysis: Efficacy and safety of biological treatment on salivary gland function in primary Sjögren's syndrome

Objective: The study aimed to assess the efficacy and safety of clinical trials of biologics in improving the salivary gland (SG) function in primary Sjögren's syndrome (pSS), which has not been analyzed critically and systematically. Methods: PubMed, Web of Science, ClinicalTrials.gov, the EU Clinical Trials Register, and the Cochrane Library were searched for clinical trials that reported effects of biological treatment on the SG function and safety in pSS patients. Inclusion criteria were defined following participants, interventions, comparisons, outcome, and study design (PICOS) recommendations. The objective index (the change of unstimulated whole saliva (UWS) flow) and the serious adverse event (SAE) were assessed as main outcome measures. A meta-analysis of the efficacy and safety of the treatment was conducted. Quality assessment, sensitivity analysis, and publication bias were assessed. The effect size together with a 95% confidence interval was used to estimate the efficacy and safety of biological treatment and was plotted as a forest plot. Results: The literature search yielded 6,678 studies, nine of which fulfilled the inclusion criteria, with seven randomized controlled trials (RCTs) and two non-RCT clinical studies. Generally, biologics do not significantly increase UWS from the baseline of pSS patients compared to the control group at a matched time point (p = 0.55; standard mean difference, SMD = 0.05; 95% confidence interval, CI: -0.11 and 0.21). However, pSS patients with shorter disease duration (≤3 years; SMD = 0.46; 95% CI: 0.06 and 0.85) were prone to have a better response to biological treatment by showing higher increased UWS than patients with longer disease duration (> 3 years; SMD = -0.03; 95% CI: -0.21 and 0.15) (p = 0.03). For the meta-analysis of the safety of biological treatment, the SAEs in the biologics group were significantly higher than those of the control group (p = 0.0021; log odds ratio, OR = 1.03; 95% CI: 0.37 and 1.69). Conclusion: Biological intervention during the early course of the disease may benefit pSS patients better than that during the late course. Significantly, more SAEs in the biologics group indicate that the safety of biologics needs to be addressed for future biological clinical trials and treatment.