Effects of PEMF and LIPUS Therapy on the Expression of Genes Related to Peripheral Nerve Regeneration in Schwann Cells

Peripheral nerve regeneration remains a major challenge in neuroscience, despite advancements in understanding its mechanisms. Current treatments, including nerve transplantation and drug therapies, face limitations such as invasiveness and incomplete recovery of nerve function. Physical therapies, like pulsed electromagnetic fields (PEMF) and low-intensity ultrasound (LIPUS), are gaining attention for their potential to enhance regeneration. This study analyzes the effects of PEMF and LIPUS on gene expression in human primary Schwann cells, which are crucial for nerve myelination and repair. Key genes involved in neurotrophin signaling (NGF, BDNF), inflammation (IL-1β, IL-6, IL-10, TNF-α, TGF-β), and regeneration (CRYAB, CSPG, Ki67) were assessed. The results of this study reveal that combined PEMF and LIPUS therapies promote Schwann cell proliferation, reduce inflammation, and improve the regenerative environment, offering potential for optimizing these therapies for clinical use in regenerative medicine.

Recent Advances in Basic Studies of Low-Intensity Pulsed Ultrasound in Periodontal Tissue Regeneration: A Systematic Review

Approximately half of the adult population is suffering from periodontal disease, and conventional periodontal treatment strategies can only slow the progression of the disease. As a kind of tissue engineering, periodontal regeneration brings hope for the treatment of periodontal disease. Low-intensity pulsed ultrasound (LIPUS) is a form of ultrasound with a frequency of 1-3 MHz and a much lower intensity (< 1W/cm2) than traditional ultrasound energy and output. LIPUS has been adopted for a variety of therapeutic purposes due to its bioeffects such as thermal, mechanical, and cavitation effects, which induce intracellular biochemical effects and lead to tissue repair and regeneration ultimately. In this systematic review, we summarize the basic research of LIPUS in the treatment of periodontal disease in periodontal disease animal models and the influence of LIPUS on the biological behavior (including promoting osteogenic differentiation of stem cells and inhibiting inflammatory response) and potential mechanism of periodontal ligament stem cells (PDLSCs), hoping to provide new ideas for the treatment of periodontal disease. We believe that LIPUS can be used as an auxiliary strategy in the treatment of periodontal disease and play an exciting and positive role in periodontal regeneration.

Exosomes derived from periodontitis induce hepatic steatosis through the SCD-1/AMPK signaling pathway

AIM

To investigate the impact of exosomes released by Porphyromonas gingivalis-Lipopolysaccharide activated THP-1 macrophages and human periodontal ligament fibroblasts on hepatocyte fat metabolism.

RESULTS

The liver of rats with experimental periodontitis showed obvious steatosis and inflammation compared with control rats. The culture supernatant of macrophages and human periodontal ligament fibroblasts (hPDLFs), when stimulated with Pg-LPS, induced lipogenesis in HepG2 cells. Furthermore, the lipid-promoting effect was effectively inhibited by the addition of the exosome inhibitor GW4869. Subsequently, we isolated exosomes from cells associated with periodontitis. Exosomes released by Pg-LPS-stimulated macrophages and hPDLFs are taken up by hepatocytes, causing mRNA expression related to fat synthesis, promoting triglyceride synthesis, and aggravating NAFLD progression. Finally, two sets of exosomes were injected into mice through the tail vein. In vivo experiments have also demonstrated that periodontitis-associated exosomes promote the development of hepatic injury and steatosis, upregulate SCD-1 expression and inhibit the AMPK signaling pathway.

CONCLUSIONS

In conclusion, we found that exosomes associated with periodontitis promote hepatocyte adipogenesis by increasing the expression of SCD-1 and suppressing the AMPK pathway, which indicates that close monitoring of the progression of stomatopathy associated extra-oral disorders is important and establishes a theoretical foundation for the prevention and management of fatty liver disease linked to periodontitis.

Anti-resorption role of low-intensity pulsed ultrasound (LIPUS) during large-scale bone reconstruction using porous titanium alloy scaffolds through inhibiting osteoclast differentiation

BACKGROUND

Ti6Al4V biomaterials combine with low-intensity pulsed ultrasound (LIPUS) has been reported with great bone regeneration capacity. It is important to better understand how LIPUS benefits bone microenvironment to seek for target of therapeutic medicine. Osteoclast differentiation plays a crucial role in bone resorption. Recent advances in molecular biology have revealed that N6-methyladenosine (m6A) RNA modifications can modulate biological processes, but their role in bone biology, particularly in osteoclast differentiation, remains unclear. We aim to understand how LIPUS regulates bone microenvironment especially osteoclast formation during bone regeneration to provide new therapeutic options for preventing and delaying bone resorption, thus with better bone regeneration efficiency.

RESULTS

1. LIPUS promoted bone ingrowth and bone maturity while inhibiting osteoclast formation within Ti6Al4V scaffolds in large-scale bone defect model. 2. LIPUS was found to inhibit osteoclast differentiation by decreasing the overall expression of osteoclast markers in vitro. 3. LIPUS decreases RNA m6A-modification level through upregulating FTO expression during osteoclast differentiation during. 4. Inhibiting FTO expression and function leads to less inhibition during osteoclast differentiation.

CONCLUSION

LIPUS suppresses osteoclast differentiation during bone regeneration through reducing m6A modification of osteoclastic RNAs by up regulating FTO expression.

Th2 cell regulatory and effector molecules single nucleotide polymorphisms and periodontitis

To investigate the association between T helper 2 (Th2) cell regulatory and effector molecules' genetic polymorphisms and periodontitis. Single nucleotide polymorphisms (SNPs) of 11 Th2 cell regulatory or effector molecules genes (CD28, CTLA4, IL4, IL5, IL6, IL9, IL10, IL13, IL4R, GATA3, STAT6, and rs1537415; total 130 SNPs) were studied in Chinese nonsmokers (163 periodontitis-free controls, 141 periodontitis patients) using Sequenom iPlex assays. SNPs potentially associated with periodontitis (adjusted allelic P < 0.1) in this cross-sectional study were further investigated via meta-analysis. Allele G of rs4553808 in promoter of CTLA4 was more frequently detected in periodontitis than controls (P < 0.005), but did not remain significant after age and gender adjustment. Haplotype (GTT) in a block of three CTLA4 SNPs (rs4553808, rs16840252, rs5742909) was significantly associated with periodontitis. Meta-analysis of SNPs identified indicated allele T of CTLA4 rs5742909 (3 studies; 461 control, 369 periodontitis) and allele G of IL6 rs1800796 (18 studies; 2760 control, 2442 periodontitis) were significantly associated with periodontitis (OR = 1.44 and OR = 1.30, respectively). Within limitations of this study, a haplotype of CTLA4 concerning Th2 cell regulation, may be associated with periodontitis in Chinese nonsmokers followed. Meta-analysis indicated rs5742909 of CTLA4 and rs1800796 of IL6 appeared significantly associated with periodontitis.

Periodontal tissue regeneration after low-intensity pulsed ultrasound stimulation with or without intra-marrow perforation in two-wall intra-bony defects-A pilot study in dogs

AIM

To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) with/without intra-marrow perforation (IMP) on periodontal healing in two-wall intra-bony defects in dogs.

MATERIALS AND METHODS

Two-wall intra-bony defects (5 mm wide, 5 mm deep) were created at the distal and mesial aspects of mandibular premolars in four beagle dogs (four defects per dog). The 16 defects were divided into four treatment groups: IMP, LIPUS, IMP + LIPUS (IMP/LIPUS) and control (open flap debridement). The LIPUS and IMP/LIPUS sites received daily LIPUS exposure for 3 weeks starting 1 week after surgery. The animals were euthanized 4 weeks after surgery for histologic evaluation.

RESULTS

There was significantly greater new bone formation at LIPUS (2.93 ± 0.74 mm) and IMP/LIPUS (3.18 ± 0.52 mm) sites than at control sites (1.65 ± 0.46 mm). New bone area at LIPUS (6.36 ± 2.28 mm² ) and IMP/LIPUS (6.13 ± 1.25 mm² ) sites was significantly greater than that at control sites (2.15 ± 1.75 mm² ). New cementum length at LIPUS sites (4.09 ± 0.75 mm) was significantly greater than that at control (2.29 ± 1.02 mm) and IMP (2.41 ± 0.41 mm) sites. No significant difference was observed between LIPUS and IMP/LIPUS sites in any histomorphometric parameter.

CONCLUSIONS

These findings suggest that LIPUS effectively promotes periodontal regeneration in two-wall intra-bony defects in dogs.

Understanding the pathophysiology behind chairside diagnostics and genetic testing for IL-1 and IL-6

In order for chairside diagnostic testing to make an impact on dental therapy, practitioners require a better understanding of genetic mutations contributing to the pathophysiology of periodontal disease. Commensal and pathogenic bacterial colonization in oral cavity tissues produces a cascade of proinflammatory signaling pathways ultimately detrimental to host tissues. Resolving inflammation is a multifactorial process involving the downregulation of proinflammatory cytokines while allowing commensal bacterial levels to return to normal. Because of the complicated nature of commensal bacteria and oral health homeostasis, the emphasis of dental therapy should place renewed focus on limiting destructive inflammation rather than solely eliminating bacteria. Salivary diagnostics are an easy, non-invasive way to assess inflammatory markers. Inflammatory cytokine levels can help determine the subclinical health of a patient, showing the transition from health to gingivitis, or periodontitis, prior to clinical presentation. Single nucleotide polymorphism mutations can aid in determining increased risk of developing periodontitis. Taken together, and alongside regular clinical evaluations, chairside diagnostics help individualize treatment plans to slow, or halt, the progression of disease-before tissue destruction can take place. While more studies are needed analyzing specific mutations across periodontal categories, chairside diagnostics present an exciting adjunct to improve patient care.

Low-intensity pulsed ultrasound attenuates cardiac inflammation of CVB3-induced viral myocarditis via regulation of caveolin-1 and MAPK pathways

The aggressive immunological activity elicited by acute viral myocarditis contributes to a large amount of cardiomyocytes loss and poor prognosis of patients in clinic. Low-intensity pulsed ultrasound (LIPUS), which is an effective treatment modality for osteoarthropathy, has been recently illustrated regulating the overactive inflammatory response in various diseases. Here, we aimed to investigate whether LIPUS could attenuate coxsackievirus B3 (CVB3) infection-induced injury by coordinating the inflammatory response. Male BALB/c mice were inoculated intraperitoneally with CVB3 to establish the model of acute viral myocarditis. LIPUS treatment was given on Day 1, Day 1, 3 and Day 1, 3, 5 post-inoculation, respectively. All mice were followed up for 14 days. Day 1, 3, 5 LIPUS treatment significantly improved the survival rate, attenuated the ventricular dysfunction and ameliorated the cardiac histopathological injury of CVB3-infected mice. Western blotting analysis showed Day 1, 3, 5 LIPUS treatment decreased pro-inflammatory cytokines, increased the activation of caveolin-1 and suppressed p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) signallings in heart tissue. RAW264.7 cells were treated with lipopolysaccharides (LPS) to simulate the augmented inflammatory response in vivo. LIPUS treatment on RAW264.7 inhibited the expression of pro-inflammatory cytokines, activated caveolin-1 and suppressed p38 MAPK and ERK signallings. Transfecting RAW264.7 with caveolin-1 siRNA blunted the suppression of pro-inflammatory cytokines and MAPK signallings by LIPUS treatment. Taken together, we demonstrated for the first time that LIPUS treatment attenuated the aggressive inflammatory response during acute viral myocarditis. The underlying mechanism may be activating caveolin-1 and suppressing MAPK signallings.

A potential treatment of low intensity pulsed ultrasound on cavernous nerve injury for erectile dysfunction

Erectile dysfunction after nerve injury is a common disease after radical prostatectomy. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family, which plays an important role in the survival of existing neurons, the differentiation of new neurons, and synaptic plasticity. It has been demonstrated that low-intensity pulsed ultrasound (LIPUS) accelerates bone healing and axonal regeneration after injury. LIPUS may also be able to stimulate neuronal activity and enhance the levels of neurotrophic factors. Evidence suggests that elevated levels of BDNF in the brain have protective effects against neurodegenerative diseases. Previous studies have shown that the treatment on cavernous nerve injury repair, and protective effect plus neuro-regeneration effect by low-intensity pulsed ultrasound. They shared the similar mechanism including several trophic factors stimulation, Pl3K/akt pathway activation, and anti-fibrosis mechanism. We hypothesized that due to its combined neuroregenerative and protective effects, the non-invasive and easy-to-use method of LIPUS stimulation could have a therapeutic effect on erectile dysfunction stemming from cavernous nerve injury.

Effects of Low-Intensity Pulsed Ultrasound for Preventing Joint Stiffness in Immobilized Knee Model in Rats

The purpose of this study was to examine the effect of low-intensity pulsed ultrasound (LIPUS) in preventing joint stiffness. Unilateral knee joints were immobilized in two groups of rats (n = 6/period/group). Under general anesthesia, the immobilized knee joints were exposed to LIPUS for 20 min/d, 5 d/wk, using an existing LIPUS device (LIPUS group, 1.5-MHz frequency, 1.0-kHz repetition cycle, 200-µs burst width and 30-mW/cm² power output) until endpoints (2, 4 or 6 wk). In the control group, general anesthesia alone was administered in the same manner as in the other group. The variables compared between the groups included joint angles; histologic, histomorphometric and immunohistochemical analyses; quantitative reverse transcription polymerase chain reactions; and tissue elasticity. LIPUS had a preventive effect on joint stiffness, resulting in decreased adhesion, fibrosis and inflammation and hypoxic response after joint immobilization.