The Effects of NF-kB Inhibition with p65-TMD-Linked PTD on Inflammatory Responses at Peri-implantitis Sites

Effects of thread design on soft and hard tissue healing around implants in lipopolysaccharide-induced peri-implantitis-like lesions in rat maxillae

OBJECTIVES

This study investigated the effects of thread design on the soft and hard tissues around implants in rat maxillary peri-implantitis-like lesions.

METHODS

Fourteen, 9-week-old, female Wistar rats were used in this study. Two types of grade IV titanium tissue-level implants with a standard V-shape and buttress threads were prepared (control and test implants, respectively). The control and test implants were randomly placed into healed left or right sides four weeks after first molar extraction. Daily administration of lipopolysaccharide (LPS) into the peri-implant mucosal sulcus was performed in combination with Freund's incomplete and complete adjuvants. The maxillae were harvested 16 days after LPS administration for quantitative and qualitative analyses.

RESULTS

LPS administration induced significant marginal bone loss, with increases in osteoclasts and polymorphonuclear cells around control implants. LPS administration did not change cell numbers around nor alter bone quality inside the buttress threads of the test implants, but resulted in a significant deterioration of bone quality, defined as the preferential alignment of collagen fibers inside the V-shaped threads of the control implant. LPS administration also significantly increased calprotectin production in the epithelium around the test implants and significantly increased calprotectin production in the connective tissue around both the control and test implants.

CONCLUSIONS

Buttress threads at specific angles provided resistance to LPS-induced inflammation in rats with LPS-induced peri-implantitis-like lesions. The upregulated production of calprotectin induced by LPS administration in the epithelium and connective tissues around the test implants may facilitate inflammation control around implants.

Experimental models for peri-implant diseases: a narrative review

OBJECTIVES

Peri-implant diseases, being the most common implant-related complications, significantly impact the normal functioning and longevity of implants. Experimental models play a crucial role in discovering potential therapeutic approaches and elucidating the mechanisms of disease progression in peri-implant diseases. This narrative review comprehensively examines animal models and common modeling methods employed in peri-implant disease research and innovatively summarizes the in vitro models of peri-implant diseases.

MATERIALS AND METHODS

Articles published between 2015 and 2023 were retrieved from PubMed/Medline, Web of Science, and Embase. All studies focusing on experimental models of peri-implant diseases were included and carefully evaluated.

RESULTS

Various experimental models of peri-implantitis have different applications and advantages. The dog model is currently the most widely utilized animal model in peri-implant disease research, while rodent models have unique advantages in gene knockout and systemic disease induction. In vitro models of peri-implant diseases are also continuously evolving to meet different experimental purposes.

CONCLUSIONS

The utilization of experimental models helps simplify experiments, save time and resources, and promote advances in peri-implant disease research. Animal models have been proven valuable in the early stages of drug development, while technological advancements have brought about more predictive and relevant in vitro models.

CLINICAL RELEVANCE

This review provides clear and comprehensive model selection strategies for researchers in the field of peri-implant diseases, thereby enhancing understanding of disease pathogenesis and providing possibilities for developing new treatment strategies.

Strontium Ranelate Ameliorates Intervertebral Disc Degeneration via Regulating TGF-β1/NF-κB Axis

Intervertebral disc degeneration (IVDD) is a prevalent and debilitating condition characterized by chronic back pain and reduced quality of life. Strontium ranelate (SRR) is a compound traditionally used for treating osteoporosis via activating TGF-β1 signaling pathway. Recent studies have proved the anti-inflammatory effect of SRR on chondrocytes. Although the exact mechanism of IVDD remains unclear, accumulating evidences have emphasized the involvement of multifactorial pathogenesis including inflammation, oxidative stress damage, and etc. However, the biological effect of SRR on IVDD and its molecular mechanism has not been investigated. Firstly, this study proved the decreased expression of Transforming Growth Factor-beta 1(TGF-β1) in degenerated human intervertebral disc tissues. Subsequently, we confirmed for the first time that SRR could promote cell proliferation, mitigate inflammation and oxidative stress in human nucleus pulposus cells in vitro via increasing the expression of TGF-β1 and suppressing the Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B Cells (NF-κB) pathway. The molecular docking result proved the interaction between SRR and TGF-β1 protein. To further verify this interaction, gain- and loss- of function experiments were conducted. We discovered that both TGF-β1 knockdown and overexpression influenced the activation of the NF-κB pathway. Taken together, SRR could mitigate IL-1β induced-cell dysfunction in human nucleus pulposus cells by regulating TGF-β1/NF-κB axis in vitro. Finally, the in vivo therapeutic effect of SRR on IVDD was confirmed. Our findings may contribute to the understanding of the complex interplay between inflammation and degenerative processes in the intervertebral disc and provide valuable insights into the development of targeted treatment-based therapeutics for IVDD.

Hesperidin mitigates oxidative stress-induced ferroptosis in nucleus pulposus cells via Nrf2/NF-κB axis to protect intervertebral disc from degeneration

Intervertebral disc degeneration (IVDD), a widely known contributor to low back pain (LBP), has been proved to be a global health challenging conundrum. Hesperidin (hesperetin-7-O-rutinoside, HRD) is a flavanone glycoside that belongs to the subgroup of citrus flavonoids with therapeutic effect on various diseases due to its anti-inflammatory, antioxidant properties. However, the effect of HRD on IVDD remains elusive. The human nucleus pulposus tissues were harvested for isolating human nucleus pulposus (HNP) cells to verify the expression of Nrf2. The biological effect of HRD on HNP cells were assessed in vitro, and the in vivo therapeutic effects of HRD were assessed in mice. Firstly, we found that the expression of Nrf2 was decreased with the progression of degeneration in degenerated human nucleus pulposus tissue. Subsequently, we confirmed that HRD could mitigate oxidative stress-induced ferroptosis in nucleus pulposus cells via enhancing the expression of Nrf2 axis and suppressing the NF-κB pathway to protect intervertebral disc from degeneration in vitro. Finally, the therapeutic effects of HRD were confirmed in vivo. The current study proved for the first time that HRD may protect HNP cells from degeneration by suppressing ferroptosis in an oxidative stress-dependent via enhancing the expression of Nrf2 and suppressing the NF-κB pathway. The evidence will provide a possible basis for future targeted treatment for IVDD.

Regulation of endothelial cells on the osteogenic ability of bone marrow mesenchymal stem cells in peri-implantitis

OBJECTIVES

The relationship between bone resorption and angiogenesis in peri-implantitis remains to be studied. We constructed a Beagle dog model of peri-implantitis, and extracted bone marrow mesenchymal stem cells (BMSCs) and endothelial cells (ECs) for culture. The osteogenic ability of BMSCs in the presence of ECs was investigated through an in vitro osteogenic induction model, and its mechanism was initially explored.

SUBJECTS AND METHODS

The peri-implantitis model was verified by ligation, bone loss was observed by micro-CT, and cytokines were detected by ELISA. The isolated BMSCs and ECs were cultured to detect the expression of angiogenesis, osteogenesis-related proteins, and NF-κB signaling pathway-related proteins.

RESULTS

8 weeks after surgery, the peri-implant gums were swollen, and micro-CT showed bone resorption. Compared with the control group, IL-1β, TNF-α, ANGII and VEGF were markedly increased in the peri-implantitis group. In vitro studies found that the osteogenic differentiation ability of BMSCs co-cultured with IECs was decreased, and the expression of NF-κB signaling pathway-related cytokines was increased.

CONCLUSION

Endothelial cells inhibit the osteogenic differentiation of bone marrow mesenchymal stem cells through NF-κB signaling in the environment of peri-implantitis, which may become a new target for the treatment of peri-implantitis.

Relationship of Sulfatides Physiological Function and Peroxisome Proliferator-Activated Receptor α

Sulfatides are unique sphingolipids present in the serum and the plasma membrane. Sulfatides exert important functions in a number of systems in the human body, including the nervous, immune, cardiovascular, and coagulation systems.Furthermore, it is closely related to tumor occurrence, development, and metastasis. Peroxisome proliferators-activated receptor α (PPARα) is a class of the nuclear receptor superfamily of transcription factors, which is a potential regulator of sulfatides. This review not only summarizes the current knowledge on the physiological functions of sulfatides in various systems, but also discusses the possible PPARα regulatory mechanisms in sulfatide metabolism and functions. The results of the present analysis provide deep insights and further novel ideas for expanding the research on the physiological function and clinical application of sulfatides.