Assessing the Impact of Stem Cell-based Therapy on Periodontal Health: A Meta-analysis of Clinical Studies.

OBJECTIVE: While clinical trials exploring stem cells for regenerating periodontal tissues have demonstrated positive results, there is a limited availability of systematic literature reviews on this subject. To gain a more comprehensive understanding of stem cell interventions in periodontal regeneration, this meta-analysis is undertaken to assess the beneficial effects of stem cells in human periodontal regeneration. METHODS: "PubMed," "Cochrane Library," "Web of Science," "Embase," "Wanfang," and "CNKI," were used to extract clinical studies related to the utilization of stem cells in repairing periodontal tissue defects. This search included studies published up until October 5, 2023. The inclusion criteria required the studies to compare the efficacy of stem cell-based therapy with stem cell-free therapy for regenerating periodontal tissues. Meta-analysis was conducted using Review Manager software (version 5.4). RESULTS: This meta-analysis synthesized findings from 15 selected studies investigating the impact of stem cell interventions on periodontal tissue regeneration. The "stem cell" group displayed a substantial reduction in clinical attachment level (CAL) compared to the "control" group within 3 to 12 months post-surgery. However, no significant differences in CAL gain were found between groups. Probing pocket depth (PPD) significantly decreased in the "stem cell" group compared to the "control" group, particularly for follow-up periods exceeding 6 months, and dental stem cell treatment exhibited notable improvements. Conversely, no significant differences were observed in PPD reduction. Gingival recession (GR) significantly decreased in the "stem cell" group compared to the "control" group at 3 to 12 months post-surgery. No significant differences were observed in GR reduction between groups. No significant differences were identified in cementoenamel junction-bone distance reduction, infrabony defect reduction, or bone mineral density increase between the two groups. Furthermore, no significant changes were observed in the gingival index, plaque index, or width of keratinized gingiva. CONCLUSION: In conclusion, while stem cell-based therapy offers promising prospects for periodontal defect treatment, there are notable limitations in the current body of research. Larger, multicenter, double-blind RCTs with robust methodologies are needed to provide more reliable evidence for stem cell-based intervention in periodontitis.

A High-Accuracy Detection System: Based on Transfer Learning for Apical Lesions on Periapical Radiograph.

Apical Lesions, one of the most common oral diseases, can be effectively detected in daily dental examinations by a periapical radiograph (PA). In the current popular endodontic treatment, most dentists spend a lot of time manually marking the lesion area. In order to reduce the burden on dentists, this paper proposes a convolutional neural network (CNN)-based regional analysis model for spical lesions for periapical radiographs. In this study, the database was provided by dentists with more than three years of practical experience, meeting the criteria for clinical practical application. The contributions of this work are (1) an advanced adaptive threshold preprocessing technique for image segmentation, which can achieve an accuracy rate of more than 96%; (2) a better and more intuitive apical lesions symptom enhancement technique; and (3) a model for apical lesions detection with an accuracy as high as 96.21%. Compared with existing state-of-the-art technology, the proposed model has improved the accuracy by more than 5%. The proposed model has successfully improved the automatic diagnosis of apical lesions. With the help of automation, dentists can focus more on technical and medical diagnoses, such as treatment, tooth cleaning, or medical communication. This proposal has been certified by the Institutional Review Board (IRB) with the certification number 202002030B0.

Methylation in pericytes after acute injury promotes chronic kidney disease.

The origin and fate of renal myofibroblasts is not clear after acute kidney injury (AKI). Here, we demonstrate that myofibroblasts were activated from quiescent pericytes (qPericytes) and the cell numbers increased after ischemia/reperfusion injury-induced AKI (IRI-AKI). Myofibroblasts underwent apoptosis during renal recovery but one-fifth of them survived in the recovered kidneys on day 28 after IRI-AKI and their cell numbers increased again after day 56. Microarray data showed the distinctive gene expression patterns of qPericytes, activated pericytes (aPericytes, myofibroblasts), and inactivated pericytes (iPericytes) isolated from kidneys before, on day 7, and on day 28 after IRI-AKI. Hypermethylation of the Acta2 repressor Ybx2 during IRI-AKI resulted in epigenetic modification of iPericytes to promote the transition to chronic kidney disease (CKD) and aggravated fibrogenesis induced by a second AKI induced by adenine. Mechanistically, transforming growth factor-ß1 decreased the binding of YBX2 to the promoter of Acta2 and induced Ybx2 hypermethylation, thereby increasing α-smooth muscle actin expression in aPericytes. Demethylation by 5-azacytidine recovered the microvascular stabilizing function of aPericytes, reversed the profibrotic property of iPericytes, prevented AKI-CKD transition, and attenuated fibrogenesis induced by a second adenine-AKI. In conclusion, intervention to erase hypermethylation of pericytes after AKI provides a strategy to stop the transition to CKD.

The Therapeutic Effectiveness of Delayed Fetal Spinal Cord Tissue Transplantation on Respiratory Function Following Mid-Cervical Spinal Cord Injury.

Respiratory impairment due to damage of the spinal respiratory motoneurons and interruption of the descending drives from brainstem premotor neurons to spinal respiratory motoneurons is the leading cause of morbidity and mortality following cervical spinal cord injury. The present study was designed to evaluate the therapeutic effectiveness of delayed transplantation of fetal spinal cord (FSC) tissue on respiratory function in rats with mid-cervical spinal cord injury. Embryonic day-14 rat FSC tissue was transplanted into a C4 spinal cord hemilesion cavity in adult male rats at 1 week postinjury. The histological results showed that FSC-derived grafts can survive, fill the lesion cavity, and differentiate into neurons and astrocytes at 8 weeks post-transplantation. Some FSC-derived graft neurons exhibited specific neurochemical markers of neurotransmitter (e.g., serotonin, noradrenalin, or acetylcholine). Moreover, a robust expression of glutamatergic and γ-aminobutyric acid-ergic fibers was observed within FSC-derived grafts. Retrograde tracing results indicated that there was a connection between FSC-derived grafts and host phrenic nucleus. Neurophysiological recording of the phrenic nerve demonstrated that phrenic burst amplitude ipsilateral to the lesion was significantly greater in injured animals that received FSC transplantation than in those that received buffer transplantation under high respiratory drives. These results suggest that delayed FSC transplantation may have the potential to repair the injured spinal cord and promote respiratory functional recovery after mid-cervical spinal cord injury.