Phenotypes, roles, and modulation of regulatory lymphocytes in periodontitis and its associated systemic diseases

IRE1α regulates macrophage polarization in type 2 diabetic periodontitis through promoting endoplasmic reticulum stress

OBJECTIVES

The aim of this study was to investigate the effect of 4μ8c, an inhibitor targeting the endoplasmic reticulum stress-associated factor IRE1α, on macrophage polarization in an experimental model of diabetic periodontitis through ex vivo experiments.

MATERIALS AND METHODS

Local alveolar bone parameters were evaluated using Micro-CT following intraperitoneal administration of 4μ8c in mice with experimental diabetic periodontitis. Surface markers indicating macrophage polarization were identified using immunofluorescence. In vitro experiments were performed employing bone marrow-derived macrophages and gingival fibroblasts. Macrophage polarization was determined using flow cytometry. Principal impacted signaling pathways were identified through Western blot analysis.

RESULTS

Results from both in vitro and in vivo experiments demonstrated that 4μ8c mitigated alveolar bone resorption and inflammation in mice with diabetic periodontitis. Furthermore, it modulated macrophage polarization towards the M2 phenotype and augmented M2 macrophage polarization through the MAPK signaling pathway.

CONCLUSIONS

These findings suggest that inhibiting IRE1α can modulate macrophage polarization and alleviate ligature-induced diabetic periodontitis via the MAPK signaling pathway. This unveils a novel mechanism, offering a scientific foundation for the treatment of experimental diabetic periodontitis.

Mean platelet volume is associated with periodontitis: a cross-sectional study

BACKGROUND

It is uncertain if mean platelet volume and periodontitis are related. The objective of this study was to examine the association between levels of mean platelet volume and moderate/severe periodontitis in adult persons who inhabit the U.S.

METHODS

We screened 6,809 people from the National Health and Nutrition Examination Survey (NHANES 2009-2012). Mean platelet volume was measured in the Mobile Examination Centers (MECs) using the Beckman Coulter analyzer. The category of periodontitis was defined by the CDC/AAP using clinical periodontal parameters. Multiple logistic regression models were employed to examine the distribution for covariate differences across the various independent groups. Four models were employed to examine the relationship between mean platelet volume level and periodontitis. Smoothed curve fitting was utilized to confirm the linearity of the relationships. To determine the impact of factors on the connection between MPV and periodontitis, subgroup analysis and interaction testing were utilized.

RESULTS

Results from the multiple logistic regression analysis indicate a significant association between moderate/severe periodontitis and the mean platelet level, even after considering any potential confounding variables (OR = 1.090, 95% CI: 1.019-1.166, P-value = 0.01211). Additionally, those in the upper tertile of mean platelet volume levels had a 21.6% higher probability of developing periodontitis when compared with those in the least tertile of mean platelet levels (OR = 1.216, 95% CI:1.052-1.406, P-value = 0.00816). Moreover, it showed a positive correlation between mean platelet volume (MPV) and moderate/severe periodontitis. Subgroup analyses indicated a positive association between the level of mean platelet volume and moderate/severe periodontitis among individuals who were under 60 years of age, had low income, were obese, never smoked, were heavy drinkers, had hypertension, and had no cardiovascular disease (p < 0.05). However, none of the subgroups exhibited significant interactions (p for interaction > 0.05).

CONCLUSION

A correlation has been found between mean platelet volume levels and periodontal disease in individuals residing in the United States.

Role of the Systemic Inflammatory Response Index in Predicting Disease Severity and Prognosis in Idiopathic Pulmonary Arterial Hypertension

Introduction

Mounting evidence indicates a possible connection between the systemic inflammatory response index (SIRI) and the prognosis of heart failure, but its role in idiopathic pulmonary arterial hypertension (IPAH) is not well understood. This study aimed to investigate the relationship between SIRI and variables such as functional ability, echocardiography results, hemodynamic measurements, and long-term outcomes in patients with IPAH.

Methods

The study included 426 consecutive IPAH patients who underwent right heart catheterization at Fuwai Hospital from January 2013 to December 2020. SIRI was calculated using composite inflammation indicators from routine blood tests. The main outcome measure was clinical deterioration. Spearman correlation coefficients were used to assess associations between SIRI and indicators of IPAH severity. Receiver operating characteristic (ROC) curve analysis was conducted to determine the optimal SIRI threshold and predictive ability. Kaplan-Meier analysis and Cox proportional hazard models were used to examine the relationship between SIRI and clinical deterioration.

Results

SIRI showed positive associations with indicators such as N-terminal pro-brain natriuretic peptide, right ventricular end-diastolic diameter, pericardial effusion, mean pulmonary arterial pressure, and pulmonary vascular resistance. Conversely, SIRI had inverse relationships with 6-minute walking distance and left ventricular end-diastolic diameter. Kaplan-Meier curves revealed a significantly higher rate of clinical deterioration in individuals with SIRI > 0.741 compared to those with SIRI ≤ 0.741 (P < 0.001). Adjusted Cox analysis showed SIRI remained an independent predictor of clinical worsening (hazard ratio 1.366, 95% confidence interval 1.073-1.738, P = 0.011). ROC analysis demonstrated SIRI provided additional predictive value beyond the risk assessment score of the European Society of Cardiology/European Respiratory Society.

Discussion

In summary, SIRI could predict the severity and prognosis of IPAH independently. It was associated with various indicators of IPAH severity and was a significant predictor of clinical deterioration. SIRI also offered additional predictive value beyond existing risk assessment scores.

Eldecalcitol effectively prevents alveolar bone loss by partially improving Th17/Treg cell balance in diabetes-associated periodontitis

Background: Diabetes-associated periodontitis (DPD) is an inflammatory and destructive disease of periodontal tissues in the diabetic population. The disease is manifested as more severe periodontal destruction and is more difficult to treat when compared with periodontitis (PD). Eldecalcitol (ELD) is a novel active vitamin D3 analog; however, little clinical evidence is available on its role on improving PD and DPD, and its specific mechanisms remain unclear. In this study, we evaluated the preventative effects of ELD toward PD and DPD and explored its underlying molecular mechanisms. Methods: Experimental PD and DPD mouse models were established by ligation combined with lipopolysaccharide (LPS) from Porphyromonas gingivalis injection in C57BL/6J and C57BLKS/J Iar- + Leprdb/+Leprdb (db/db) mice, respectively. Simultaneously, ELD (0.25 μg/kg) was orally administered to mice via an intragastric method. Micro-computed tomography (CT), hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), and tartrate-resistant acid phosphatase (TRAP) staining were used to evaluate alveolar bone alterations in vivo. Flow cytometry, immunofluorescence, and real-time polymerase chain reaction (qRT-PCR) were also used to examine gene expression and probe systemic and local changes in Treg and Th17 cell numbers. Additionally, western blotting and immunofluorescence staining were used to examine changes in STAT3/STAT5 signaling. Results: Micro-CT and HE staining showed that the DPD group had higher alveolar bone loss when compared with the PD group. After applying ELD, alveolar bone loss decreased significantly in both PD and DPD groups, and particularly evident in the DPD group. IHC and TRAP staining also showed that ELD promoted osteoblast activity while inhibiting the number of osteoclasts, and after ELD treatment, the receptor activator of nuclear factor-κB ligand (RANKL) to osteoprotegerin (OPG) ratio decreased. More importantly, this decreasing trend was more obvious in the DPD group. Flow cytometry and qRT-PCR also showed that the systemic Th17/Treg imbalance in PD and DPD groups was partially resolved when animals were supplemented with ELD, while immunofluorescence staining and qRT-PCR data showed the Th17/Treg imbalance was partially resolved in the alveolar bone of both ELD supplemented groups. Western blotting and immunofluorescence staining showed increased p-STAT5 and decreased p-STAT3 levels after ELD application. Conclusion: ELD exerted preventative effects toward PD and DPD by partially rectifying Th17/Treg cell imbalance via STAT3/STAT5 signaling. More importantly, given the severity of DPD, we found ELD was more advantageous in preventing DPD.

Impact of the host response and osteoblast lineage cells on periodontal disease

Periodontitis involves the loss of connective tissue attachment and alveolar bone. Single cell RNA-seq experiments have provided new insight into how resident cells and infiltrating immune cells function in response to bacterial challenge in periodontal tissues. Periodontal disease is induced by a combined innate and adaptive immune response to bacterial dysbiosis that is initiated by resident cells including epithelial cells and fibroblasts, which recruit immune cells. Chemokines and cytokines stimulate recruitment of osteoclast precursors and osteoclastogenesis in response to TNF, IL-1β, IL-6, IL-17, RANKL and other factors. Inflammation also suppresses coupled bone formation to limit repair of osteolytic lesions. Bone lining cells, osteocytes and periodontal ligament cells play a key role in both processes. The periodontal ligament contains cells that exhibit similarities to tendon cells, osteoblast-lineage cells and mesenchymal stem cells. Bone lining cells consisting of mesenchymal stem cells, osteoprogenitors and osteoblasts are influenced by osteocytes and stimulate formation of osteoclast precursors through MCSF and RANKL, which directly induce osteoclastogenesis. Following bone resorption, factors are released from resorbed bone matrix and by osteoclasts and osteal macrophages that recruit osteoblast precursors to the resorbed bone surface. Osteoblast differentiation and coupled bone formation are regulated by multiple signaling pathways including Wnt, Notch, FGF, IGF-1, BMP, and Hedgehog pathways. Diabetes, cigarette smoking and aging enhance the pathologic processes to increase bone resorption and inhibit coupled bone formation to accelerate bone loss. Other bone pathologies such as rheumatoid arthritis, post-menopausal osteoporosis and bone unloading/disuse also affect osteoblast lineage cells and participate in formation of osteolytic lesions by promoting bone resorption and inhibiting coupled bone formation. Thus, periodontitis involves the activation of an inflammatory response that involves a large number of cells to stimulate bone resorption and limit osseous repair processes.

Immunogenomics Parameters for Patient Stratification in Alzheimer's Disease

BACKGROUND

Despite the fact that only modest adaptive immune system related approaches to treating Alzheimer's disease (AD) are available, an immunogenomics approach to the study of AD has not yet substantially advanced.

OBJECTIVE

Thus, we sought to better understand adaptive immune receptor chemical features in the AD setting.

METHODS

We characterized T-cell receptor alpha (TRA) complementarity determining region-3 (CDR3) physicochemical features and identified TRA CDR3 homology groups, represented by TRA recombination reads extracted from 2,665 AD-related, blood- and brain-derived exome files.

RESULTS

We found that a higher isoelectric value for the brain TRA CDR3s was associated with a higher (clinically worse) Braak stage and that a number of TRA CDR3 chemical homology groups, in particular representing bloodborne TRA CDR3s, were associated with higher or lower Braak stages. Lastly, greater chemical complementarity of both blood- and brain-derived TRA CDR3s and tau, based on a recently described CDR3-candidate antigen chemical complementarity scoring process (https://adaptivematch.com), was associated with higher Braak stages.

CONCLUSION

Overall, the data reported here raise the questions of (a) whether progression of AD is facilitated by the adaptive immune response to tau; and (b) whether assessment of such an anti-tau immune response could potentially serve as a basis for adaptive immune receptor related, AD risk stratification?

UPR attenuates the proinflammatory effect of HPDLF on macrophage polarization

Human periodontal ligament fibroblast (HPDLF) is a major component of the resident cells in the periodontal microenvironment, and plays important roles in periodontitis through multiple mechanisms. Although lipopolysaccharide (LPS) has been shown to cause endoplasmic reticulum (ER) stress and activate the unfolded protein response (UPR) in HPDLF, the mechanisms governing HPDLF function in periodontitis are unclear. In this study, we tested the ability of unfolded protein response (UPR) to regulate HPDLF in vitro and examined the underlying mechanisms. We found LPS-pretreated HPDLF induced macrophage polarization toward M1 phenotype. UPR activation reduced the inflammatory cytokine production and downregulated the expression of TLR4 in HPDLF. The phosphorylation of NF-κB p65 and I-κB was also inhibited by UPR activation. Our findings demonstrate that the connection of LPS, UPR, and HPDLF may represent a new concrete theory of innate immunity regulation in periodontal diseases, and suggest that targeting of UPR in HPDLF may be developed as a potent therapy for periodontitis.