Sjögren's syndrome: a review of aetiology, pathogenesis, diagnosis and management

Sarcoidosis and Sjögren's syndrome: clinical and salivary evaluation

BACKGROUND

Sarcoidosis and Sjögren's syndrome are two different diseases; however, when affecting the salivary glands, both diseases exhibit similar clinical signs and symptoms, which often complicates the diagnosis. The purpose of this study was to investigate the possibility of using salivary electrophoresis to differentiate between the two diseases.

METHODS

Saliva was collected from patients with sarcoidosis and patients with Sjögren's syndrome. Salivary flow rate, total protein, and electrophoretic profiles were examined.

RESULTS

Mean salivary flow rate was 0.41 ± 0.07 ml/min/gland vs. 0.43 ± 0.07 ml/min/gland; total salivary protein was 130.0 ± 29.2 mg% vs. 104.0 ± 8.8 mg% for sarcoidosis vs. Sjögren's syndrome, respectively. No differences were observed in salivary flow rate, total salivary protein, or electrophoretic profile between patients with sarcoidosis and patients with Sjögren's syndrome (P = 0.768, 0.718, and 1.000, respectively).

CONCLUSIONS

Salivary protein electrophoresis does not appear to be useful to differentiate between sarcoidosis and Sjögren's syndrome.

Novel autoantibodies in Sjogren's syndrome

Sjogren's syndrome (SS) is defined by autoantibodies to Ro and La. The current studies identified additional autoantibodies in SS to salivary gland protein 1 (SP-1), carbonic anhydrase 6 (CA6) and parotid secretory protein (PSP). These autoantibodies were present in two animal models for SS and occurred earlier in the course of the disease than antibodies to Ro or La. Patients with SS also produced antibodies to SP-1, CA6 and PSP. These antibodies were found in 45% of patients meeting the criteria for SS who lacked antibodies to Ro or La. Furthermore, in patients with idiopathic xerostomia and xerophthalmia for less than 2 years, 76% had antibodies to SP-1 and/or CA6 while only 31% had antibodies to Ro or La. Antibodies to SP-1, CA6 and PSP may be useful markers for identifying patients with SS at early stages of the disease or those that lack antibodies to either Ro or La.

Mesenchymal stromal cells improve salivary function and reduce lymphocytic infiltrates in mice with Sjögren's-like disease

BACKGROUND

Non-obese diabetic (NOD) mice develop Sjögren's-like disease (SS-like) with loss of saliva flow and increased lymphocytic infiltrates in salivary glands (SGs). There are recent reports using multipotent mesenchymal stromal cells (MSCs) as a therapeutic strategy for autoimmune diseases due to their anti-inflammatory and immunomodulatory capabilities. This paper proposed a combined immuno- and cell-based therapy consisting of: A) an injection of complete Freund's adjuvant (CFA) to eradicate autoreactive T lymphocytes, and B) transplantations of MSCs to reselect lymphocytes. The objective of this was to test the effectiveness of CD45(-)/TER119(-) cells (MSCs) in re-establishing salivary function and in reducing the number of lymphocytic infiltrates (foci) in SGs. The second objective was to study if the mechanisms underlying a decrease in inflammation (focus score) was due to CFA, MSCs, or CFA+MSCs combined.

METHODOLOGY/PRINCIPAL FINDINGS

Donor MSCs were isolated from bones of male transgenic eGFP mice. Eight week-old female NOD mice received one of the following treatments: insulin, CFA, MSC, or CFA+MSC (combined therapy). Mice were followed for 14 weeks post-therapy. CD45(-)/TER119(-) cells demonstrated characteristics of MSCs as they were positive for Sca-1, CD106, CD105, CD73, CD29, CD44, negative for CD45, TER119, CD11b, had high number of CFU-F, and differentiated into osteocytes, chondrocytes and adipocytes. Both MSC and MSC+CFA groups prevented loss of saliva flow and reduced lymphocytic infiltrations in SGs. Moreover, the influx of T and B cells decreased in all foci in MSC and MSC+CFA groups, while the frequency of Foxp3(+) (T(reg)) cell was increased. MSC-therapy alone reduced inflammation (TNF-α, TGF-β), but the combination of MSC+CFA reduced inflammation and increased the regenerative potential of SGs (FGF-2, EGF).

CONCLUSIONS/SIGNIFICANCE

The combined use of MSC+CFA was effective in both preventing saliva secretion loss and reducing lymphocytic influx in salivary glands.

Risk factors and symptoms associated with xerostomia: a cross-sectional study

BACKGROUND

The aim of this study was to examine the symptoms and risk factors associated with self-reported xerostomia.

METHODS

Data were collected from 601 self-administered questionnaires among dental clinic attendees. Logistic regression models to estimate odds ratios and 95% confidence intervals were used to investigate the association for exposures of interest, such as socio-demographic characteristics, self-reported symptoms, oral hygiene habits and xerostomia.

RESULTS

Participants reported having dry mouth in 19.6% of cases. Xerostomia was associated with a significant increase in the odds of having dry lips, throat, eye, skin and nose. Patients with self-reported xerostomia were three times more likely to drink water to swallow food than were patients without xerstomia. Older individuals were significantly more likely to report dry mouth, and the prevalence of xerostomia increased with advancing age. The prevalence of xerostomia in patients taking one or more drugs was significantly higher compared to medication-free patients, and increased with increasing numbers of medications used. Finally, individuals with a nervous or mental disorder, or who wore removable dentures were five times more likely to develop xerostomia than patients without disorder or dentures.

CONCLUSIONS

Dentists should be familiar with the symptoms of xerostomia and be prepared to take an active role in the diagnosis, management and treatment of the oral complications.

Resolvin D1 prevents TNF-α-mediated disruption of salivary epithelial formation

Sjögren's syndrome is a chronic autoimmune disorder characterized by inflammation of salivary glands resulting in impaired secretory function. Our present studies indicate that chronic exposure of salivary epithelium to TNF-α and/or IFN-γ alters tight junction integrity, leading to secretory dysfunction. Resolvins of the D-series (RvDs) are endogenous lipid mediators derived from DHA that regulate excessive inflammatory responses leading to resolution and tissue homeostasis. In this study, we addressed the hypothesis that activation of the RvD1 receptor ALX/FPR2 in salivary epithelium prevents and/or resolves the TNF-α-mediated disruption of acinar organization and enhances monolayer formation. Our results indicate that 1) the RvD1 receptor ALX/FPR2 is present in fresh, isolated cells from mouse salivary glands and in cell lines of salivary origin; and 2) the agonist RvD1 (100 ng/ml) abolished tight junction and cytoskeletal disruption caused by TNF-α and enhanced cell migration and polarity in salivary epithelium. These effects were blocked by the ALX/FPR2 antagonist butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe. The ALX/FPR2 receptor signals via modulation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways since, in our study, blocking PI3K activation with LY294002, a potent and selective PI3K inhibitor, prevented RvD1-induced cell migration. Furthermore, Akt gene silencing with the corresponding siRNA almost completely blocked the ability of Par-C10 cells to migrate. Our findings suggest that RvD1 receptor activation promotes resolution of inflammation and tissue repair in salivary epithelium, which may have relevance in the restoration of salivary gland dysfunction associated with Sjögren's syndrome.