The effect of colchicine on alveolar bone loss in ligature-induced periodontitis

Nanoparticle based periodontal drug delivery - A review on current trends and future perspectives

Introduction

Periodontitis is a chronic inflammatory disease, resulting due to host immune response against subgingival biofilm. Most conventional treatment protocols aim to control the subgingival biofilm by mechanical means, such as dental scaling and root planning, and frequently accompanied by antibacterial co-adjuvant therapies, including antibiotics, antiseptics, or probiotics. Local drug delivery facilitates administration of a lower dose of the drug to the target site, but at higher concentration, thereby reducing systemic adverse effects and toxicity. The present systematic review was conducted with the aim of identifying and reporting nanoparticle based periodontal drug delivery systems, with a specific focus on current trends and future perspectives in this field.

Materials & methods

Comprehensive literature search, restricted to published reports in English language between January 2000 and February 2022, was done electronically and manually. Search queries were addressed to the following electronic databases including, PubMed (MEDLINE), Science Direct (Elsevier), Cochrane Library, Web of Science (Clarivate Analytics) and Scholar (Google). Database search returned 780 results which were screened based on title, author names and publication dates, to identify 13 studies fulfilling the review criteria.

Results

Data from the 13 included studies were reviewed and tabulated, elaborating the type of nanoparticle used, drug delivered and tissues/cells/subcellular components targeted by periodontal drug delivery. While majority of the studies were conducted in vitro, there were 3 in vivo studies and 3 clinical studies. Using nanotechnology for drug delivery resulted in better inhibition of bacterial growth, inflammatory modulation favoring resolution of periodontitis and capability for early tissue regeneration.

Conclusion

Recent developments in nanotechnology have enabled targeted local delivery of drugs and anti-inflammatory biomolecules, in synergy with nanoparticles, towards periodontal pathogens, inflammatory cells and periodontal tissues. Further research evaluating clinical periodontal disease management through nanoparticle based local drug delivery drugs is highly recommended.

A Review of the Rational and Current Evidence on Colchicine for COVID-19

The current coronavirus disease (COVID-19) pandemic has affected millions of individuals worldwide. Despite extensive research efforts, few therapeutic options currently offer direct clinical benefits for COVID-19 patients. Despite the advances in our understanding of COVID-19, the mortality rates remain significantly high owing to the high viral transmission rates in several countries and the rise of various mutations in the SARS-CoV-2. One currently available and widely used drug that combines both anti-inflammatory and immunomodulatory actions is colchicine, which has been proposed as a possible treatment option for COVID-19. Colchicine still did not get much attention from the medical and scientific communities despite its antiinflammatory and immunomodulatory mechanisms of action and positive preliminary data from early trials. This literature review article provides the scientific rationale for repurposing colchicine as a potential therapy for COVID-19. Further, we summarize colchicine's mechanisms of action and possible roles in COVID-19 patients. Finally, we supplement this review with a summary of the doses, side effects, and early efficacy data from clinical trials to date. Despite the promising early findings from multiple observational and clinical trials about the potential of colchicine in COVID-19, the data from the RECOVERY trial, the largest COVID-19 randomized controlled trial (RCT) in the world, showed no evidence of clinical benefits in mortality, hospital stays, or disease progression (n = 11340 patients). However, multiple other smaller clinical trials showed significant clinical benefits. We conclude that while current evidence does not support the use of colchicine for treating COVID-19, the present body of evidence is heterogeneous and inconclusive. The drug cannot be used in clinical practice or abandoned from clinical research without additional large RCTs providing more robust evidence. At present, the drug should not be used except for investigational purposes.

Immunotherapy with regulatory T and B cells in periodontitis

Periodontitis (PD), also known as gum disease, is a condition causing inflammatory bone resorption and tooth loss. Regulatory T cells (Tregs) and regulatory B cells (Bregs) are vital in controlling the immune response and hence play a role in infections and peripheral tolerance adjustment. These cells have immunosuppressive and tissue-repairing capabilities that are important for periodontal health; however, in inflammatory circumstances, Tregs may become unstable and dysfunctional, accelerating tissue deterioration. In recent years, Regulatory cell-mediated immunotherapy has been shown to be effective in many inflammatory diseases. Considering the roles of Tregs and Bregs in shaping immune responses, this study aimed to review the published articles in this field to provide a comprehensive view of the existing knowledge about the role of regulatory T and B cells, as well as their therapeutic applications in PD.

Ligature induced periodontitis in rats causes gut dysbiosis leading to hepatic injury through SCD1/AMPK signalling pathway

AIMS

Previous studies have demonstrated that chronic periodontitis (CP) is closely associated with the occurrence and development of a variety of systemic diseases. In this study, we successfully constructed a rat CP model through dental silk ligation, and the corresponding inflammatory reactions and fatty lesions were observed in the liver.

MAIN METHODS

Sprague-Dawley rats (n = 6) underwent tooth ligation at the bilateral first molars with silk thread to induce CP and were sacrificed 8 weeks later and compared to non-ligated rats (n = 6). RNA sequencing and 16S rRNA analysis were performed to determine the molecular mechanisms of CP involved in inducing liver disease. Alveolar bone loss, liver enzymes, mandible and liver histopathology, and inflammatory responses were compared between groups.

KEY FINDINGS

RNA sequencing of liver tissue showed that the expression of SCD1 increased significantly in CP rats compared to controls. KEGG enrichment analysis showed that the AMPK signalling pathway may be involved in liver steatosis. The intestinal flora of faecal samples of rats were analysed by 16S rRNA sequencing, and the results indicated that the intestinal flora of the CP group was evidently imbalanced. The expression levels of tight junction proteins (ZO-1, occludin, and claudin-1) were significantly reduced in CP rats. Meanwhile, increases in serum IL-1β and lipopolysaccharide in CP rats reflected a systemic inflammatory response.

SIGNIFICANCE

CP may be involved in the occurrence and development of hepatic injury and liver steatosis, and its mechanism may be related to the oral-gut-liver axis and SCD1/AMPK signal activation in the liver.

Targeting TSP-1 decreased periodontitis by attenuating extracellular matrix degradation and alveolar bone destruction

An important factor in periodontitis pathogenesis relates to a network of interactions of various cytokines. Thrombospondin-1 (TSP-1) is upregulated in several inflammatory diseases. We previously found that Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS)-induced TSP-1 production, and that TSP-1 simultaneously and effectively elevated inflammatory cytokines in THP-1 macrophages. This suggests that TSP-1 plays an important role in the pathology of periodontitis. However, the function of TSP-1 on oral cells is largely unknown. This study aimed to elucidate the underlying molecular mechanisms of TSP-1 in human periodontal fibroblasts (hPDLFs). We demonstrated that TSP-1 is highly expressed in the gingival crevicular fluid of patients with chronic periodontitis and in the inflammatory gingival tissues of rats. TSP-1 overexpression or treatment with recombinant human TSP-1(rTSP-1) promoted the expression of MMP-2, MMP-9 and RANKL/OPG in hPDLFs, while anti-TSP-1 inhibited cytokines production from P. gingivalis LPS-treated hPDLFs. Additional experiments showed that SB203580 (a special p38MAPK inhibitor) inhibited MMP-2, MMP-9 and RANKL/OPG expression induced by rTSP-1. Thus, TSP-1 effectively promoted P. gingivalis LPS-induced periodontal tissue (extracellular matrix (ECM) and alveolar bone) destruction by the p38MAPK signalling pathway, indicating that it may be a potential therapeutic target against periodontitis.

Caloric restriction prevents alveolar bone loss in the experimental periodontitis in obese rats

AIMS

It has been shown that periodontitis, can be modified by systemic changes, including behavioral factors, such as diet. Caloric restriction is one of the dietary therapeutic strategies indicated for obesity. It is associated with several benefits, among them, modulation of the inflammatory response. The aim of this study was to verify whether caloric restriction in obese rats changes the progression of experimental ligature-induced periodontitis.

MATERIALS AND METHODS

Forty-eight Wistar rats were used for 24 weeks and initially fed with cafeteria diet during 12 weeks. The animals were divided into four groups according to the caloric restriction and experimental periodontitis. The cotton thread was placed around the mandibular first molars, for 15 days, before the end of the experiment. Rats submitted to caloric restriction received, from the 13th week of the experimental protocol, 70% of the food intake compared to the ad libitum animals of other study of the our research group. Alveolar bone loss was assessed using macroscopic morphometric analysis. Analyzes of clinical periodontal measures, biometrics, serum biomarkers and biochemical parameters were performed.

KEY FINDINGS

Caloric restriction decreased the alveolar bone loss in the periodontitis group when compared to the group that received a cafeteria diet with periodontitis. Moreover, the results demonstrate the improvement in the glycemic profile, without prejudice to bone tissue biomarkers.

SIGNIFICANCE

Based on the results, caloric restriction reduces the progression of alveolar bone loss in rats with experimental periodontitis, in addition to presenting benefits in biometric data, decreasing both glycemic profile and clinical periodontal measures.

Interleukin-35 inhibits alveolar bone resorption by modulating the Th17/Treg imbalance during periodontitis

AIM

T lymphocytes play a central role during the pathogenesis of periodontitis, and the imbalance between the pathogenic T-helper type 17 (Th17) and protective T-regulatory (Treg) lymphocytes determines the tooth-supporting alveolar bone resorption. Interleukin (IL)-35 is a novel anti-inflammatory cytokine with therapeutic properties in diseases whose pathogenesis is associated with the Th17/Treg imbalance; however, its role during periodontitis has not been established yet. This study aimed to elucidate whether IL-35 inhibits the alveolar bone resorption during periodontitis by modulating the Th17/Treg imbalance.

MATERIALS AND METHODS

Mice with ligature-induced periodontitis were treated with locally or systemically administrated IL-35. As controls, periodontitis-affected mice without IL-35 treatment and non-ligated mice were used. Alveolar bone resorption was measured by micro-computed tomography and scanning electron microscopy. The Th17/Treg pattern of the immune response was analysed by qPCR, ELISA, and flow cytometry.

RESULTS

IL-35 inhibited alveolar bone resorption in periodontitis mice. Besides, IL-35 induced less detection of Th17 lymphocytes and production of Th17-related cytokines, together with higher detection of Treg lymphocytes and production of Treg-related cytokines in periodontitis-affected tissues.

CONCLUSION

IL-35 is beneficial in the regulation of periodontitis; particularly, IL-35 inhibited alveolar bone resorption and this inhibition was closely associated with modulation of the periodontal Th17/Treg imbalance.

Anti‑gouty arthritis and anti‑hyperuricemia properties of celery seed extracts in rodent models

Gout is a type of serious arthritis that is caused by hyperuricemia. Celery is an umbelliferous plant that was shown to exhibit anti‑inflammatory activity in rodent. The present study aimed to investigate the effects and potential preliminary mechanisms of celery seed aqueous extract (CSAE) and celery seed oil extract (CSOL) for gout treatment. The components of CSAE and CSOL were systematically analyzed. In mice with hyperuricemia induced by potassium oxonate and yeast extract, CSAE and CSOL treatment reduced the serum levels of uric acid and xanthine oxidase. In addition, CSAE and CSOL reduced the levels of reactive oxygen species and increased the serum levels of superoxide dismutase and glutathione peroxidase in mouse serum. In rats with acute gouty arthritis induced by intra‑articular injection of monosodium urate crystals, CSAE and CSOL treatment alleviated the swelling of the ankle joints and reduced inflammatory cell infiltration around the ankle joints. In addition, CSAE and CSOL reduced the levels of interleukin (IL)‑1β and tumor necrosis factor α and increased the levels of IL‑10. The results of the present study suggested that celery seed extracts may have anti‑gout properties, partially through anti‑inflammatory and antioxidative effects.