Gavage-administered lactoferrin promotes palatal expansion stability in a dose-dependent manner

Medication-related osteonecrosis of the jaw: evolving research for multimodality medical management

PURPOSE

Medication-related osteonecrosis of the jaw (MRONJ) is a debilitating side effect of antiresorptive and antiangiogenic agents that can lead to progressive bone destruction in the maxillofacial region. Dental surgery, including tooth extractions, commonly trigger the onset of MRONJ. While guidelines suggest avoiding extraction when possible, complete avoidance is not always feasible, as necrosis can develop from dental and periodontal disease without dental procedures. The goal of this article is to provide an update review of current preventive and therapeutic approaches for MRONJ.

METHODS

A comprehensive electronic search was conducted on PubMed/MEDLINE, Embase, and Scopus databases. All English articles encompassing randomized controlled trials, systematic reviews, observational studies, and case studies were reviewed. The current medical treatments and adjuvant therapies for managing MRONJ patients were critically assessed and summarized.

RESULTS

Pentoxifylline and alpha tocopherol (PENT-E), teriparatide, photobiomodulation (PBM), photodynamic therapy (PDT), and the use of growth factors have shown to enhance healing in MRONJ patients. Implementing these methods alone or in conjunction with surgical treatment has been linked to reduced discomfort and improved wound healing and increased new bone formation.

DISCUSSION

While several adjuvant treatment modalities exhibit promising results in facilitating the healing process, current clinical practice guidelines predominantly recommend antibiotic therapy as a non-surgical approach, primarily addressing secondary infections in necrotic areas. However, this mainly addresses the potential infectious complication of MRONJ. Medical approaches including PENT-E, teriparatide, PBM, and PDT can result in successful management and should be considered prior to taking a surgical approach. Combined medical management for both preventing and managing MRONJ holds potential for achieving optimal clinical outcomes and avoiding surgical intervention, requiring further validation through larger studies and controlled trials.

What is the effect of lactoferrin on oral and jawbone tissue repair? A systematic review

Currently, there is growing interest in the potential use of lactoferrin (LTF), a member of the transferrin family, for the improvement of tissue healing. In this sense, a literature search was conducted to integrate data published on the effect of LTF on jawbone repair. PubMed/MEDLINE, Scopus, Embase, Web of Science, LILACS, and Cochrane databases were retrieved according to the PRISMA 2020 statement. Articles in English, Spanish, and Portuguese were recovered, with no year restriction. In vitro, in vivo, and clinical studies were selected. A total of 742 articles were retrieved, 11 of which met the inclusion criteria (5 in vitro and 5 in vivo studies, and one clinical trial). The included data demonstrated wide variations in study design and LTF therapy protocols. Cell proliferation and viability were the primary outcomes evaluated in the in vitro studies, all of which reported a potential effect of LTF on the repair process. Of three in vivo studies, one reported a reduction in the overall healing rate, whereas the other two showed that LTF inhibited bone resorption and increased bone formation. The clinical trial's findings showed that LTF is a potential promoter of wound repair in patients with medication-related osteonecrosis of the jaws. Overall, data from the studies support a potential effect of LTF therapy on the process of jawbone repair.

The mechanism underlying the remodeling effect of lactoferrin on midpalatal sutures during maxillary expansion and relapse in rats

INTRODUCTION

The remodeling effects of intragastric administration and intramaxillary injection of lactoferrin (LF) on midpalatal sutures (MPS) during maxillary expansion and relapse in rats were studied to explore the underlying bone remodeling mechanism.

METHODS

Using a rat model of maxillary expansion and relapse, rats were treated with LF by intragastric administration (1 g·kg^-1·d^-1) or intramaxillary injection (5 mg·25 μl^-1·d^-1). The effects of LF on the osteogenic and osteoclast activities of MPS were observed by microcomputed tomography, histologic staining, and immunohistochemical staining, and the expressions of key factors in the extracellular regulated protein kinase 1/2 (ERK1/2) pathway and osteoprotegerin (OPG)-receptor activator of nuclear factor-KB ligand (RANKL)-receptor activator of nuclear factor-KB (RANK) axis were detected.

RESULTS

Compared with the group with maxillary expansion alone, osteogenic activity was relatively enhanced, whereas osteoclast activity was relatively weakened in the groups administered LF, and the phosphorylated-ERK1/2: ERK1/2 and OPG: RANKL expression ratios increased significantly. The difference was more significant in the group administered LF intramaxillary.

CONCLUSIONS

Administration of LF promoted osteogenic activity at MPS and inhibited osteoclast activity during maxillary expansion and relapse in rats, which may have occurred through regulation of the ERK1/2 pathway and the OPG-RANKL-RANK axis. The efficiency of intramaxillary LF injection was greater than that of intragastric LF administration.

Suppressing STAT3 activation impairs bone formation during maxillary expansion and relapse

OBJECTIVES

The mid-palatal expansion technique is commonly used to correct maxillary constriction in dental clinics. However, there is a tendency for it to relapse, and the key molecules responsible for modulating bone formation remain elusive. Thus, this study aimed to investigate whether signal transducer and activator of transcription 3 (STAT3) activation contributes to osteoblast-mediated bone formation during palatal expansion and relapse.

METHODOLOGY

In total, 30 male Wistar rats were randomly allocated into Ctrl (control), E (expansion only), and E+Stattic (expansion plus STAT3-inhibitor, Stattic) groups. Micro-computed tomography, micromorphology staining, and immunohistochemistry of the mid-palatal suture were performed on days 7 and 14. In vitro cyclic tensile stress (10% magnitude, 0.5 Hz frequency, and 24 h duration) was applied to rat primary osteoblasts and Stattic was administered for STAT3 inhibition. The role of STAT3 in mechanical loading-induced osteoblasts was confirmed by alkaline phosphatase (ALP), alizarin red staining, and western blots.

RESULTS

The E group showed greater arch width than the E+Stattic group after expansion. The differences between the two groups remained significant after relapse. We found active bone formation in the E group with increased expression of ALP, COL-I, and Runx2, although the expression of osteogenesis-related factors was downregulated in the E+stattic group. After STAT3 inhibition, expansive force-induced bone resorption was attenuated, as TRAP staining demonstrated. Furthermore, the administration of Stattic in vitro partially suppressed tensile stress-enhanced osteogenic markers in osteoblasts.

CONCLUSIONS

STAT3 inactivation reduced osteoblast-mediated bone formation during palatal expansion and post-expansion relapse, thus it may be a potential therapeutic target to treat force-induced bone formation.