Comparative evaluation of salivary soluble CD44 levels in periodontal health and disease

Current Evidence and Perspectives of Cluster of Differentiation 44 in the Liver's Physiology and Pathology

Cluster of differentiation 44 (CD44), a multi-functional cell surface receptor, has several variants and is ubiquitously expressed in various cells and tissues. CD44 is well known for its function in cell adhesion and is also involved in diverse cellular responses, such as proliferation, migration, differentiation, and activation. To date, CD44 has been extensively studied in the field of cancer biology and has been proposed as a marker for cancer stem cells. Recently, growing evidence suggests that CD44 is also relevant in non-cancer diseases. In liver disease, it has been shown that CD44 expression is significantly elevated and associated with pathogenesis by impacting cellular responses, such as metabolism, proliferation, differentiation, and activation, in different cells. However, the mechanisms underlying CD44's function in liver diseases other than liver cancer are still poorly understood. Hence, to help to expand our knowledge of the role of CD44 in liver disease and highlight the need for further research, this review provides evidence of CD44's effects on liver physiology and its involvement in the pathogenesis of liver disease, excluding cancer. In addition, we discuss the potential role of CD44 as a key regulator of cell physiology.

Salivary Soluble CD44 Level in Chronic Periodontitis - A Comparative Assessment between Preoperative and Postoperative Scaling and Root Planing

Background

Salivary biomarkers can be used to diagnose illnesses, track their course, and gauge a patient's response to therapy. Inflammatory circumstances result in higher sCD44 levels. The most typical inflammatory disorder connected to periodontal tissue is called periodontitis. Therefore, the purpose "of the current study was to compare the levels of sCD44 in patients with chronic periodontitis before and after scaling and root planing.

Objectives

1) Determining CD44 concentrations in healthy individuals' spit. 2) To quantify CD44 levels in the saliva of individuals with persistent periodontitis. The third objective is to compare the levels of CD44 that can be dissolved in saliva between those with healthy gums and those with active periodontitis. 4) Assessing CD44 levels in saliva after "scaling and root planing in patients with chronic periodontitis."

Materials and Methods

Half of the study participants were classified as having chronic periodontitis, while the other half had healthy gums. Participants with healthy gums and those with chronic periodontitis had their plaque levels, gingival status, and testing depths measured. All the same, data were calculated in persons with chronic periodontitis one month after they had "scaling and root planing done. Clinical attachment levels were evaluated before scaling and root planing was performed on patients with chronic periodontitis and again one month afterwards. Patients with chronic periodontitis," those whose condition had not improved following scaling and root planing (SRP), and healthy individuals all had spit tests conducted after a month. The concentration of sCD44 in the saliva was determined with a chemically coupled immunosorbent assay.

Results

Salivary sCD44 levels were substantially greater in people with chronic periodontitis than in people without the condition. After one month of scaling and root planing in patients with chronic periodontitis, sCD44 levels drastically dropped (p < 0.0001).

Conclusion

Chronic periodontitis is linked to elevated levels of salivary sCD44. sCD44 can be employed as a possible salivary biomarker for chronic Periodontitis.

Decreased Levels of Soluble CD44 in a High-Risk Population following a Smoking Cessation Program

Tobacco is a risk factor of head and neck cancer (HNC) and smoking cessation alone may reduce HNC risk by 70%. Soluble CD44 (solCD44), a cell surface receptor linked to cell proliferation and migration, and total protein (TP) levels can detect early HNC. This study aims to determine whether salivary solCD44 and TP levels in oral rinses change following a smoking cessation program. 150 smokers provided oral rinse samples at baseline and at a 12-month follow-up after participation in a smoking cessation program. Assays to measure levels of solCD44, TP, and cotinine, a metabolite used as a biomarker of tobacco exposure, were completed. A paired-samples t-test was used to determine whether there was a statistically significant (p < 0.05) mean difference in biomarker levels before and after the program. Baseline and at 12-month follow-up data were available for 88 subjects, 21 of whom quit smoking entirely. Mean levels of solCD44 significantly decreased by 0.412 ng/mL from baseline to the 12-month follow-up, p = 0.010. There was no significant difference in mean TP levels, p = 0.975. Mean cotinine levels decreased significantly by 74.7 ng/mL, p = 0.035. This is the first work demonstrating an association between smoking cessation and decreased solCD44 levels in oral rinses. Decreased expression of the tumorigenic CD44 may be one mechanism by which smoking cessation lowers cancer risk.

Correlation of Soluble CD44 Expression in Saliva and CD44 Protein in Oral Leukoplakia Tissues

The aim of this study was to determine whether and how pan-CD44 protein expression in leukoplakia tissues correlates with positive SolCD44 test presence and their role in oral leukoplakia. SolCD44 and total protein expression in saliva were determined using an OncAlert^® Oral Cancer Rapid test. Comparison of paired associations of total protein, SolCD44, mean number of CD44 expressed epithelial layers in leukoplakia tissue, and macrophages below the basement membrane between control group and patients with leukoplakia showed statistically significant results (p < 0.0001). It is shown that the total protein indicates low or elevated risk of possible malignant transformation processes in leukoplakia. Statistically significant differences between higher total protein level and clinical forms of oral leukoplakia (p < 0.0001), as well as CD44-labeled epithelial cell layer decrease (p < 0.0001), were found. This possibly points to the onset of the stemness loss in leukoplakia tissue. CD9 antigen expression in the exosomes of the oral epithelium explained the intercellular flow of SolCD44 and other fluids in the leukoplakia area. We conclude that the OncAlert^® Oral Cancer Rapid test is a valuable screening method in daily clinical practice, in terms of complementing clinical diagnostics methods and to assess the potential for early malignancy.

Proteolytic Processing of CD44 and Its Implications in Cancer

CD44 is a transmembrane glycoprotein expressed in several healthy and tumor tissues. Modifications in its structure contribute differently to the activity of this molecule. One modification that has provoked interest is the consecutive cleavage of the CD44 extracellular ectodomain by enzymes that belong mainly to the family of metalloproteases. This process releases biologically active substrates, via alternative splice forms of CD44, that generate CD44v3 or v6 isoforms which participate in the transcriptional regulation of genes and proteins associated to signaling pathways involved in the development of cancer. These include the protooncogene tyrosine-protein kinase Src (c-Src)/signal transducer and activator of transcription 3 (STAT3), the epithelial growth factor receptor, the estrogen receptor, Wnt/βcatenin, or Hippo signaling pathways all of which are associated to cell proliferation, differentiation, or cancer progression. Whereas CD44 still remains as a very useful prognostic cell marker in different pathologies, the main topic is that the generation of CD44 intracellular fragments assists the regulation of transcriptional proteins involved in the cell cycle, cell metabolism, and most importantly, the regulation of some stem cell-associated markers.

VEGF, Microvessel Density, and CD44 as Inflammation Markers in Peri-implant Healthy Mucosa, Peri-implant Mucositis, and Peri-implantitis: Impact of Age, Smoking, PPD, and Obesity

Several biologic processes affect the supporting peri-implant tissue leading to implant failure and complications, mainly referred to inflammation that is still poorly investigated in the peri-implant soft tissues. Our aim was to investigate in peri-implant healthy mucosa, peri-implant mucositis, and peri-implantitis the expression of some angiogenesis markers highly associated with inflammation, and evaluate its relationships with age, smoking, peri-implant pocket depth (PPD), and body max index (BMI). Moreover, we wanted to study the impact of these clinical parameters in the disease pathogenesis. Forty-eight total patients were recruited. Sixteen had at least one successfully osteointegrated dental implant (group A) and 32 had at least one osseointegrated implant in need of a peri-implant treatment for inflammatory/infectiveous reasons: precisely 16 for mucositis (group B) and 16 for peri-implantitis (group C). VEGF, CD34, and CD44 immunohistochemical expression was evaluated in the interproximal biopsies of marginal peri-implant tissue and correlated with the clinical parameters. A significant difference between groups in mean PPD was found, while the distribution by age, gender, smoking, and BMI resulted similar. Group C had significantly higher levels of VEGF, CD34, and CD44 expression compared to the other groups. VEGF, CD34, CD44, and peri-implant pocket depth were all positively correlated. Our study revealed that peri-implantitis is a condition characterized by unique and distinctive features. Our results supported that PPD has a great impact on the peri-implantitis and it is closely related to the inflammation marker expression. The identification of specific biomarkers might help in choosing distinct treatment approaches for target individuals.

Cell-adhesion molecules and their soluble forms: Promising predictors of "tumor progression" and relapse in leukemia

Some surface markers are used to discriminate certain leukemic subpopulations that retain a greater oncogenic potential than others, and, for this reason, they were termed as leukemic stem cells, similar to the concept of cancer stem cells in carcinoma. Among these surface markers are proteins involved in cell-cell adhesion or cell-matrix adhesion, and they may play a role in the relapse of leukemia, similar to metastasis in carcinomas. The most important are epithelial cadherin, neural cadherin, epithelial cell-adhesion molecule, and CD44, which can be cleaved and released, and their soluble forms were found increased in serum levels of cancer patients, being implicated, in some cases, with progression, metastases, and relapse. In this review, we highlighted the role of these four adhesion molecules in carcinomas and hematological malignancies, mainly leukemia, and discuss if the serum levels of soluble forms can be correlated with the surface protein status on the leukemic cells. Accession of the soluble forms looks attractive, but their use as markers in cancer must be studied in association with other parameters, as there are significant changes in levels in other pathological conditions besides cancer. Studies correlating the levels of the forms with the status of the membrane-bound proteins in leukemic (stem) cells and correlating those parameters with relapse in leukemia may afford important knowledge and applicability of those serum markers in clinical practice. For instance, the expression of the membrane-bound forms of these adhesion proteins may have promising clinical use in leukemia and other hematological malignancies.

Immune response mediated by Th1 / IL-17 / caspase-9 promotes evolution of periodontal disease

INTRODUCTION

Periodontitis is characterized by inflammatory mediators beyond T lymphocyte function and phenotype (Th1/Th2/Th17). The clinical diversity in periodontitis makes it difficult to characterize the immune response in patients. This study evaluated the profile of the adaptive immune response in the periodontal disease model.

METHODS

72 rats (Wistar) were divided into a control group (CTL/day 0) and periodontitis (PD15/15 days and PD60/60 days). In the PD15 and PD60 groups, periodontal disease was induced by ligature with a silk thread placed in the cervical region of the upper first molar. After euthanasia, the periodontal tissue was analyzed by flow cytometry (CD4, CD8, CD25, CD44), semi-quantitative RT-PCR (T-bet, GATA-3, RORγt), semi-quantitative RT-PCR and ELISA IFN-γ, TNF-α, IFN-γ, IL-4, IL-6, IL-10, IL-17) and by Western blotting (Caspase-9, PCNA).

RESULTS

The number of CD4⁺CD25⁺, CD4⁺CD44⁺, CD8⁺CD25⁺ and CD8⁺CD44⁺ cells and expression levels of T-bet and GATA-3 are increased in the PD60 group compared to PD15 and CTL. The RORγ-t gene transcript increased in the PD15 group in relation to PD60 and CTL. The cytokines IFN-γ, TNF-α and IL-17 increased in the PD60 group in relation to PD15. The expression of Caspase-9 was higher in the PD60 group than in PD15.

CONCLUSIONS

The results suggest that the evolution of gingivitis to periodontitis is related to the accumulation of activated Th1 cells (IFN-γ and TNF-α) associated with the presence of increased IL-17. Studies with inhibitors of these cytokines in periodontal disease may lead to therapy directed at blocking the inflammatory process in this pathology, interrupting bone loss.

Environmental lead effects on gene expression in oral epithelial cells

BACKGROUND AND OBJECTIVE

Host responses in periodontitis span a range of local and emigrating cell types and biomolecules. Accumulating evidence regarding the expression of this disease across the population suggests some component of genetic variation that controls onset and severity of disease, in concert with the qualitative and quantitative parameters of the oral microbiome at sites of disease. However, there remains little information regarding the capacity of accruing environmental stressors or modifiers over a lifespan at both the host genetic and microbial ecology levels to understand fully the population variation in disease. This study evaluated the impact of environmental lead exposure on the responses of oral epithelial cells to challenge with a model pathogenic oral biofilm.

METHODS AND RESULTS

Using NanoString technology to quantify gene expression profiles of an array of 511 host response-associated genes in the epithelial cells, we identified an interesting primary panel of basal responses of the cells with numerous genes not previously considered as major response markers for epithelial cells, eg, interleukin (IL)-32, CTNNB1, CD59, MIF, CD44 and CD99. Even high levels of environment lead had little effect on these constitutive responses. Challenge of the cells with the biofilms (Streptococcus gordonii/Fusobacterium nucleatum/Porphyromonas gingivalis) resulted in significant increases in an array of host immune-related genes (134 of 511). The greatest magnitude in differential expression was observed with many genes not previously described as major response genes in epithelial cells, including IL-32, CD44, NFKBIA, CTSC, TNFAIP3, IL-1A, IL-1B, IL-8 and CCL20. The effects of environmental lead on responses to the biofilms were mixed, although levels of IL-8, CCL20 and CD70 were significantly decreased at lead concentrations of 1 and/or 5 μmol/L.

CONCLUSION

The results provided new information on a portfolio of genes expressed by oral epithelial cells, targeted substantial increases in an array of immune-related genes post-biofilm challenge, and a focused impact of environmental lead on these induced responses.

The association between oral hygiene and periodontitis: a systematic review and meta-analysis

Objective: Dental plaque accumulation and inadequate personal oral hygiene (OH) are known major risk factors of periodontitis. Nevertheless, the magnitude of their effects has not yet been the subject of a meta-analysis. Material and methods: The Medline and Scopus databases were searched up to May 2016. Observational studies were eligible if they assessed associations between OH and periodontitis in adult subjects. A multivariate random-effects meta-analysis was used to pool the effects of fair/poor OH versus good OH on periodontitis across studies. The associations between oral care habits and periodontitis were also assessed. Results: A total of 50 studies were eligible; 15 were used for pooling the effect of fair OH versus good OH and poor OH versus good OH on periodontitis, with pooled odds ratios (ORs) of 2.04 [95% confidence interval (CI): 1.65–2.53] and 5.01 (95% CI: 3.40–7.39), respectively. Eleven studies examined oral care habits measured according to toothbrushing regularity and dental visit frequency; pooled ORs of 0.66 (95% CI: 0.47–0.94) and 0.68 (95% CI: 0.47–0.98) were obtained, respectively. Conclusions: Fair to poor OH increases the risk of periodontitis by two- to five-fold. This risk can be reduced by regular toothbrushing and dental visits.