Acinar Atrophy, Fibrosis and Fatty Changes Are Significantly More Common than Sjogren’s Syndrome in Minor Salivary Gland Biopsies

Características clínicas, histopatológicas e inmunohistoquímicas de pacientes con síndrome seco y biopsia de glándula salival con puntaje de foco de 1 o más

Introducción. El síndrome de Sjögren es una enfermedad autoinmunitaria sistémica. Se ha descrito la utilidad de la inmunohistoquímica de la biopsia de glándula salival menor por su utilidad en la caracterización del fenotipo de los linfocitos en los casos de difícil diagnóstico.

OBJETIVO

Describir las variables sociodemográficas, clínicas, serológicas, histopatológicas e inmunohistoquímicas de los pacientes con síndrome seco en quienes se practicó biopsia de glándula salival menor que resultó con un puntaje de foco de uno o más. Materiales y métodos. Se adelantó un estudio observacional, retrospectivo, en el que se incluyeron pacientes en estudio por posible síndrome seco y cuya biopsia de glándula salival menor estaba disponible y había obtenido un puntaje de foco de uno o más. En la biopsia de la glándula salival menor se realizó inmunohistoquímica con cromógeno rojo para la identificación de los linfocitos T CD8 positivos y marrón, para los linfocitos T CD4 positivos. Se determinó la relación de los marcadores CD20:CD3 y CD4:CD8 con el equipo MoticEasyScan Pro-6™ (MOTIC) y el software QuPath™. El análisis de las variables cualitativas se realizó mediante la aplicación de la prueba de ji al cuadrado (c2) o la prueba exacta de Fisher; para el de las variables cuantitativas, la prueba seleccionó según el supuesto de normalidad.

RESULTADOS

Se analizaron 28 pacientes, 16 con síndrome de Sjögren y 8 con poliautoinmunidad. Se encontró una asociación entre la presencia de atrofia glandular en la biopsia de glándula salival menor y el desarrollo de poliautoinmunidad (OR = 11,1; IC 95%: 1,12-112; p = 0,033). Las relaciones CD20:CD3 y CD4:CD8 fueron normales, sin diferencias estadísticamente significativas entre pacientes con síndrome de Sjögren y sin él. En el subgrupo de pacientes con síndrome de Sjögren hubo predominancia de los linfocitos T CD4, 15 de los 16 casos tenían una relación CD4:CD8 igual o mayor de 2:1.

CONCLUSIONES

Se encontró una asociación entre la atrofia glandular y la presencia de poliautoinmunidad, así como predominancia de los linfocitos T CD4 en los pacientes con síndrome de Sjögren. Esto resalta el posible valor de aplicar la inmunohistoquímica en las biopsias de glándula salival menor en este grupo.

Immune and non-immune mediators in the fibrosis pathogenesis of salivary gland in Sjögren's syndrome

Sjögren's syndrome (SS) or Sjögren's disease (SjD) is a systemic autoimmune disease clinically manifested as sicca symptoms. This disease primarily impacts the functionality of exocrine glands, specifically the lacrimal and salivary glands (SG). SG fibrosis, an irreversible morphological change, is a severe consequence that occurs in the later stages of the disease due to sustained inflammation. However, the mechanism underlying SG fibrosis in SS remains under-investigated. Glandular fibrosis may arise from chronic sialadenitis, in which the interactions between infiltrating lymphocytes and epithelial cells potentially contributes to fibrotic pathogenesis. Thus, both immune and non-immune cells are closely involved in this process, while their interplays are not fully understood. The molecular mechanism of tissue fibrosis is partly associated with an imbalance of immune responses, in which the transforming growth factor-beta (TGF-β)-dependent epithelial-mesenchymal transition (EMT) and extracellular matrix remodeling are recently investigated. In addition, viral infection has been implicated in the pathogenesis of SS. Viral-specific innate immune response could exacerbate the autoimmune progression, resulting in overt inflammation in SG. Notably, post-COVID patients exhibit typical SS symptoms and severe inflammatory sialadenitis, which are positively correlated with SG damage. In this review, we discuss the immune and non-immune risk factors in SG fibrosis and summarize the evidence to understand the mechanisms upon autoimmune progression in SS.

Serum α-amylase correlates with xerostomia in patients with primary Sjögren's disease

Sjögren's disease is one of the most common systemic autoimmune diseases with hallmark features of sicca (dryness) symptoms of the eyes and mouth. There are a variety of ways to quantify xerostomia. α-Amylase is an enzyme secreted by the pancreas and salivary glands. While not specific to salivary glands, it may be measured as a surrogate marker of their output. Therefore, in this short investigation, we determined if there were any associations of serum α-amylase with subjective and objective markers of xerostomia. This investigation found a correlation between objective and subjective markers of xerostomia and α-amylase which suggests that measuring this analyte is a novel adjunct to qualifying xerostomia in the clinic.

Prosthodontic implications of saliva and salivary gland dysfunction

PURPOSE

To provide a detailed overview of the fundamentals of saliva constituents and production. The review outlines the clinical manifestations as a consequence of salivary gland dysfunction and management strategies for patients with salivary gland dysfunction. Prosthodontic implications of saliva and salivary gland dysfunction are presented.

MATERIALS AND METHODS

English-language literature relating to saliva constituents, physiologic saliva production, clinical manifestations secondary to salivary gland dysfunction, salivary biomarkers, and management strategies were retrieved via electronic search. Relevant articles were summarized for this manuscript with a view toward providing pragmatic information.

RESULTS

Saliva is produced by three pairs of major and minor salivary glands. The major salivary glands, namely, the parotid, submandibular, and sublingual glands, contribute approximately 90% of saliva production. Saliva contains serous and mucinous secretions produced by different types of cells within salivary glands. Parasympathetic and sympathetic fibers innervate the major salivary glands, and upon stimulation, the parasympathetic innervation increases serous secretions, while the sympathetic innervation increases protein secretion. Stimulated saliva is mainly derived from the parotid glands which are composed of serous acini, while unstimulated saliva is mainly derived from the submandibular glands which are composed of mixed seromucous acini. As major salivary glands contribute the most to salivary flow, local or systemic factors influencing those glands can disrupt saliva production resulting in clinically significant oral manifestations.

CONCLUSION

This review provides a fundamental overview of saliva production. In addition, the review highlights the various clinical manifestations secondary to salivary gland dysfunction, explores salivary biomarkers for screening of systemic diseases, discusses management strategies for patients with salivary gland dysfunction, and outlines the prosthodontic implications of saliva and salivary gland dysfunction.

Extracellular matrix turnover in salivary gland disorders and regenerative therapies: Obstacles and opportunities

Salivary gland (SG) extracellular matrix (ECM) has a major influence on tissue development, homeostasis, and tissue regeneration after injury. During aging, disease, and physical insult, normal remodeling of the SG microenvironment (i.e. ECM) becomes dysregulated, leading to alterations in matrix composition which disrupt tissue architecture/structure, alter cell activity, and negatively impact gland function. Matrix metalloproteinases (MMPs) are a large and diverse family of metalloendopeptidases which play a major role in matrix degradation and are intimately involved in regulating development and cell function; dysregulation of these enzymes leads to the production of a fibrotic matrix. In the SG this altered fibrotic ECM (or cell microenvironment) negatively impacts normal cell function and the effectiveness of gene and stem cell therapies which serve as a foundation for many SG regenerative therapies. For this reason, prospective regenerative strategies should prioritize the maintenance and/or restoration of a healthy SG ECM. Mesenchymal stem cells (MSCs) have great potential for mitigating damage to the SG microenvironment by ameliorating inflammation, reducing fibrosis, and repairing the damaged milieu of extracellular regulatory cues, including the matrix. This review addresses our current understanding of the impact of aging and disease on the SG microenvironment and suggests critical deficiencies and opportunities in ECM-targeted therapeutic interventions.

Outline of Salivary Gland Pathogenesis of Sjögren's Syndrome and Current Therapeutic Approaches

Sjögren's syndrome (SS) is an autoimmune disease characterized by the involvement of exocrine glands such as the salivary and lacrimal glands. The minor salivary glands, from which tissue samples may be obtained, are important for the diagnosis, evaluation of therapeutic efficacy, and genetic analyses of SS. In the onset of SS, autoantigens derived from the salivary glands are recognized by antigen-presenting dendritic cells, leading to the activation of T and B cells, cytokine production, autoantibody production by plasma cells, the formation of ectopic germinal centers, and the destruction of salivary gland epithelial cells. A recent therapeutic approach with immune checkpoint inhibitors for malignant tumors enhances the anti-tumor activity of cytotoxic effector T cells, but also induces SS-like autoimmune disease as an adverse event. In the treatment of xerostomia, muscarinic agonists and salivary gland duct cleansing procedure, as well as sialendoscopy, are expected to ameliorate symptoms. Clinical trials on biological therapy to attenuate the hyperresponsiveness of B cells in SS patients with systemic organ involvement have progressed. The efficacy of treatment with mesenchymal stem cells and chimeric antigen receptor T cells for SS has also been investigated. In this review, we will provide an overview of the pathogenesis of salivary gland lesions and recent trends in therapeutic approaches for SS.