Sjögren Syndrome: New Insights in the Pathogenesis and Role of Nuclear Medicine

Functional significance of DNA methylation: epigenetic insights into Sjögren's syndrome

Sjögren's syndrome (SjS) is a systemic, highly diverse, and chronic autoimmune disease with a significant global prevalence. It is a complex condition that requires careful management and monitoring. Recent research indicates that epigenetic mechanisms contribute to the pathophysiology of SjS by modulating gene expression and genome stability. DNA methylation, a form of epigenetic modification, is the fundamental mechanism that modifies the expression of various genes by modifying the transcriptional availability of regulatory regions within the genome. In general, adding a methyl group to DNA is linked with the inhibition of genes because it changes the chromatin structure. DNA methylation changes the fate of multiple immune cells, such as it leads to the transition of naïve lymphocytes to effector lymphocytes. A lack of central epigenetic enzymes frequently results in abnormal immune activation. Alterations in epigenetic modifications within immune cells or salivary gland epithelial cells are frequently detected during the pathogenesis of SjS, representing a robust association with autoimmune responses. The analysis of genome methylation is a beneficial tool for establishing connections between epigenetic changes within different cell types and their association with SjS. In various studies related to SjS, most differentially methylated regions are in the human leukocyte antigen (HLA) locus. Notably, the demethylation of various sites in the genome is often observed in SjS patients. The most strongly linked differentially methylated regions in SjS patients are found within genes regulated by type I interferon. This demethylation process is partly related to B-cell infiltration and disease progression. In addition, DNA demethylation of the runt-related transcription factor (RUNX1) gene, lymphotoxin-α (LTA), and myxovirus resistance protein A (MxA) is associated with SjS. It may assist the early diagnosis of SjS by serving as a potential biomarker. Therefore, this review offers a detailed insight into the function of DNA methylation in SjS and helps researchers to identify potential biomarkers in diagnosis, prognosis, and therapeutic targets.

Effect of adipose tissue-derived stem cells therapy on clinical response in patients with primary Sjogren's syndrome

The purpose of this trial was to clinically assess the effect and safety of Adipose Tissue-derived Stem Cells (ADSCs) treatment on primary Sjogren's Syndrome (pSS). In this 6-month randomized, triple-blind, placebo-controlled clinical trial, pSS patients were randomly assigned to two groups. After demographic characteristics and clinical examination were achieved, local injection of ADSCs into bilateral glands was performed with patients in ADSCs group (n = 35) and placebo solution was used for another group (n = 39) at three time points. Patients were followed up at 1-, 3- and 6-month. At each visit, studies of clinical and laboratory outcomes, as well as subjective symptoms, were conducted. A total of 74 subjects who met the including criteria were allocated in two groups and eventually 64 subjects (86.5%) completed the treatments and the follow-up assessments. Secretion of salivary and lachrymal glands were significantly improved in 3-month (P < 0.05). A great improvement of European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) was found after ADSCs treatment with intergroup comparison from baseline to follow-up (P < 0.05). There is also a significant difference of European Alliance of Associations for Rheumatology SS Patient Reported Index (ESSPRI) between the two groups in the follow-up (P < 0.05). A significant abatement of IgG, IgM, C3, C4 and ESR between two groups was observed in part of follow-up time points (P < 0.05). The ADSCs therapy can provide relief of oral and eye's dryness in our trial in a short time and has potential improvement of subjective and systemic syndromes of pSS.