Differential regulation of NPY and SP receptor expression in STRO-1+ve PDLSCs by inflammatory cytokines

Nociceptor-Macrophage Interactions in Apical Periodontitis: How Biomolecules Link Inflammation with Pain

Periradicular tissues have a rich supply of peripheral afferent neurons, also known as nociceptive neurons, originating from the trigeminal nerve. While their primary function is to relay pain signals to the brain, these are known to be involved in modulating innate and adaptive immunity by initiating neurogenic inflammation (NI). Studies have investigated neuroanatomy and measured the levels of biomolecules such as cytokines and neuropeptides in human saliva, gingival crevicular fluid, or blood/serum samples in apical periodontitis (AP) to validate the possible role of trigeminal nociceptors in inflammation and tissue regeneration. However, the contributions of nociceptors and the mechanisms involved in the neuro-immune interactions in AP are not fully understood. This narrative review addresses the complex biomolecular interactions of trigeminal nociceptors with macrophages, the effector cells of the innate immune system, in the clinical manifestations of AP.

Neural Regulations in Tooth Development and Tooth-Periodontium Complex Homeostasis: A Literature Review

The tooth-periodontium complex and its nerves have active reciprocal regulation during development and homeostasis. These effects are predominantly mediated by a range of molecules secreted from either the nervous system or the tooth-periodontium complex. Different strategies mimicking tooth development or physiological reparation have been applied to tooth regeneration studies, where the application of these nerve- or tooth-derived molecules has been proven effective. However, to date, basic studies in this field leave many vacancies to be filled. This literature review summarizes the recent advances in the basic studies on neural responses and regulation during tooth-periodontium development and homeostasis and points out some research gaps to instruct future studies. Deepening our understanding of the underlying mechanisms of tooth development and diseases will provide more clues for tooth regeneration.

α-Cyperone Ameliorates Lipopolysaccharide-Induced Inflammation and Apoptosis of Periodontal Ligament Stem Cells via Blocking the Toll-Like Receptor 4/NF-κB Signaling

Periodontitis is a long-lasting inflammatory microbial sickness that could cause damage to the periodontal ligament, gums, cementum and alveolar bone directly. Cyperus rotundus is a common traditional Chinese medicine clinically with many pharmacological activities, α-Cyperone is a bioactive ingredient abundant in Cyperus rotundus, few studies have focused on its anti-fungal and anti-oxidative stress activities in mice, during this research, we firstly investigated the impact of α-Cyperone on PDLSCs inflammatory by LPS stimulation. Our findings illustrated that α-Cyperone exerted no influence on PDLSCs viability at concentrations lower than 60 μM, and the release of inflammatory cytokines decreased with an increase in LPS concentration. Meanwhile, we found that α-Cyperone effectively restrained LPS-induced PDLSC cell apoptosis by CCK-8 cell viability assay and TUNEL-positive staining. Furthermore, the TLR4 expression and NF-κB kinase activation were greatly repressed by α-Cyperone treatment in LPS-induced PDLSCs inflammatory model. Subsequently, enhanced TLR4 expression was observed to reverse the suppressed release of inflammatory cytokines and decreased apoptosis effects mediated by α-Cyperone in LPS-cotreated PDLSCs, indicating that the deactivation of TLR4 and downstream NF-κB were implicated in favoring α-Cyperone-triggered protective effects of LPS in PDLSCs.

Neurogenic Appendicitis: A Reappraisal of the Clinicopathological Features and Pathogenesis

In 1921; Masson and Maresch first coined the term “neurogenic appendicitis (NA)” to describe “neuroma-like” lesions in the appendix. To date, our knowledge about NA is limited; therefore, we conducted a comprehensive analysis of the literature (1921 to 2020) to examine the clinicopathological features of NA. We also addressed the pathophysiology of acute abdominal pain and fibrosis in this entity. We performed a meta-analysis study by searching the PubMed database, using several keywords, such as: “appendix,” “neurogenic,” “obliterative,” “neuroma,” “fibrous obliteration,” “appendicopathy,” and “appendicitis.” Our study revealed that patients with NA usually present clinically with features of acute appendicitis, bud2t they have grossly unremarkable appendices. Histologically, the central appendiceal neuroma was the most common histological variant of NA, followed by the submucosal and intramucosal variants. To conclude, NA represents a form of neuroinflammation. The possibility of NA should be considered in patients with clinical features of acute appendicitis who intraoperatively show a grossly unremarkable appendix. Neuroinflammation and neuropeptides play roles in the development of pain and fibrosis in NA.