An Update on the Lived Experience of Dry Mouth in Sjögren's Syndrome Patients

Senescence and fibrosis in salivary gland aging and disease

Salivary gland hypofunction is highly prevalent in aged and diseased individuals leading to significant discomfort and morbidity. One factor that contributes to salivary gland hypofunction is cellular aging, or senescence. Senescent cells can impair gland function by secreting paracrine-acting growth factors and cytokines, known as senescence-associated secretory phenotype (SASP) factors. These SASP factors stimulate inflammation, propagate the senescent phenotype through the bystander effect, and stimulate fibrosis. As senotherapeutics that target senescent cells have shown effectiveness in limiting disease manifestations in other conditions, there is interest in the use of these drugs to treat salivary gland hypofunction. In this review, we highlight the contribution of senescence and fibrosis to salivary gland pathologies. We also discuss therapeutic approaches to eliminate or modulate the senescent SASP phenotype for treating age-related salivary gland diseases and extending health span.

The experience of dry mouth and screening for Sjogren's syndrome by the dentist: patient-reported experiences

BACKGROUND

One of the main clinical features of Sjögren's Syndrome is oral dryness, which is associated with an increased risk of oral diseases and a lower oral life quality. Dentists have a key role to play in the Sjögren's Syndrome diagnosis and specific management. In parallel, many patients rely on patient associations, which offer opportunities for members to seek information about their disease and share their experiences. We aimed to evaluate patients experience with dry mouth and the importance of dentists in Sjögren's Syndrome diagnosis and its management.

METHODS

We carried out a cross-sectional survey in 2020 based on a questionnaire drafted in collaboration with clinicians specializing in Sjögren's Syndrome and patient members of a patient association. The survey consisted of 27 questions divided into the six sections: the patient's profile, their experience with dry mouth and treatments used to manage, characteristics of experienced oral-health problems, effects of dry mouth and its consequences on the quality of life, evaluation of the dentist role in the screening of Sjögren's Syndrome, and its management by the dentist. Recruitment was carried out via the patient association's newsletter, website, and social networks. Sjögren's diagnosis was self-reported.

RESULTS

One thousand four hundred fifty-eight patients fully responded to the survey. Most respondents were women over 50 and were mainly concerned with primary Sjögren's Syndrome. Overall, 86.97% of respondents reported experiencing frequent or constant dry mouth and 69.01% declared having had oral problems (candidiasis, oral pain, loss or alteration of taste, bad breath, gastro-esophageal reflux). We found a positive correlation between the frequency of dry mouth and each of these disorders and between the frequency of dry mouth and alterations in life quality dimensions. Finally, 74.9% of patients did not report having dry mouth to their dentist prior to being diagnosed with Sjögren's Syndrome and 58% had not been informed about the oral risks associated with it by their dentist and sought information themselves or from their physician.

CONCLUSIONS

We confirm the significant consequences of dry mouth on oral quality of life, as well as its association with oral health problems. Sjögren's Syndrome screening by dentists should be increased, as well as prevention of the associated oral health risks.

The plasma exosomes from patients with primary Sjögren's syndrome contain epithelial cell-derived proteins involved in ferroptosis

Primary Sjögren's syndrome (pSS) is an autoimmune disease represented by exocrine gland epithelial cell lesions. However, the mechanism underlying these lesions remains unclear. This study analyzed the plasma exosomes of pSS patients using proteomics and revealed the presence of 24 differentially expressed proteins (DEPs) involved in the primary biological processes and signaling pathways related to ferroptosis. The DEPs enriched in the ferroptosis-related items were represented by downregulated ceruloplasmin (CP) and transferrin (TF). CC analysis of GO enrichment showed that CP and TF were localized at the apical plasma membrane, which is currently found only in epithelial cells. PPI analysis indicated that these exosomal DEPs formed a clustering network containing CP and TF. Among them, C5, C9, Haptoglobin (HP), and SERPING1 interacted directly with CP and TF. Notably, the expression of these proteins significantly decreased in both the pSS and secondary Sjögren's syndrome (sSS) plasma exosomes but not in non-autoimmune sicca syndrome (nSS). In addition, their expression levels were significantly different in the exosomes and plasma. More importantly, the plasma and salivary exosomes of pSS patients contain higher levels of exocrine gland epithelial autoantigens SSA and SSB than those of healthy controls, and epithelial cells with positive labial glands biopsy (LGB) were more susceptible to ferroptosis than those with negative LGB. The results indicated that ferroptosis may be closely related to SS epithelial cell lesions. KEY MESSAGES: • pSS plasma exosomes contain epithelial cell-derived proteins involved in ferroptosis. • Complement C5 and C9 may be new molecules involved in ferroptosis and play a crucial role in pSS epithelial cell pathology. • The serum exosomes from pSS patients, not nSS patients, contain ferroptosis-related proteins. • The changes in the ferroptosis-related protein content in the exosomes can better reflect the state of the epithelial cell lesions than those in the plasma.

Root Canal Infection and Its Impact on the Oral Cavity Microenvironment in the Context of Immune System Disorders in Selected Diseases: A Narrative Review

The oral cavity has a specific microenvironment, and structures such as teeth are constantly exposed to chemical and biological factors. Although the structure of the teeth is permanent, due to exposure of the pulp and root canal system, trauma can have severe consequences and cause the development of local inflammation caused by external and opportunistic pathogens. Long-term inflammation can affect not only the local pulp and periodontal tissues but also the functioning of the immune system, which can trigger a systemic reaction. This literature review presents the current knowledge on root canal infections and their impact on the oral microenvironment in the context of immune system disorders in selected diseases. The result of the analysis of the literature is the statement that periodontal-disease-caused inflammation in the oral cavity may affect the development and progression of autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, or Sjogren's syndrome, as well as affecting the faster progression of conditions in which inflammation occurs such as, among others, chronic kidney disease or inflammatory bowel disease.

Tuft Cells Are Present in Submandibular Glands Across Species

Tuft cells are bottle-shaped, microvilli-projecting chemosensory cells located in the lining of a variety of epithelial tissues and, following their identification approximately 60 years ago, have been linked to immune system function in a variety of epithelia. Until recently, Tuft cells had not been convincingly demonstrated to be present in salivary glands with their detection by transmission electron microscopy only shown in a handful of earlier studies using rat salivary glands, and no follow-up work has been conducted to verify their presence in salivary glands of other species. Here, we demonstrate that Tuft cells are present in the submandibular glands of various species (i.e., mouse, pig and human) using transmission electron microscopy and confocal immunofluorescent analysis for the POU class 2 homeobox 3 (POU2F3), which is considered to be a master regulator of Tuft cell identity.

A Possible Novel Protective Effect of Piceatannol against Isoproterenol (ISO)-Induced Histopathological, Histochemical, and Immunohistochemical Changes in Male Wistar Rats

Dry mouth is characterized by lower saliva production and changes in saliva composition. In patients with some salivary gland function remaining, pharmaceutical treatments are not recommended; therefore, new, more effective methods of promoting saliva production are needed. Hence, this study aimed to provide an overview of the histological changes in the salivary gland in the model of isoproterenol (ISO)-induced degenerative changes in male Wistar rats and to evaluate the protective effect of piceatannol. Thirty-two male Wistar rats were randomly divided into four groups: the control group, the ISO group, and the piceatannol (PIC)-1, and -2 groups. After the third day of the experiment, Iso (0.8 mg/100 g) was injected intraperitoneally (IP) twice daily into the animals. PIC was given IP in different daily doses (20 and 40 mg/kg) for three days before ISO and seven days with ISO injection. The salivary glands were rapidly dissected and processed for histological, histochemical, immunohistochemical (Ki-67), and morphometric analysis. Upon seven days of treatment with ISO, marked hypertrophy was observed, along with an increased number of positive Ki-67 cells. Proliferation was increased in some endothelial cells as well as in ducts themselves. Despite the significant decrease in proliferation activity, the control group did not return to the usual activity level after treatment with low-dose PIC. Treatment with a high dose of PIC reduced proliferative activity to the point where it was substantially identical to the results seen in the control group. An ISO-driven xerostomia model showed a novel protective effect of piceatannol. A new era of regenerative medicine is dawning around PIC’s promising role.