Transplantation of Noncultured Stromal Vascular Fraction Cells of Adipose Tissue Ameliorates Osteonecrosis of the Jaw–Like Lesions in Mice

Abstract

The precise pathoetiology and effective treatment strategies for bisphosphonate-related osteonecrosis of the jaw (BRONJ) remain unknown. Transplantation of noncultured stromal vascular fraction (SVF) cells has been shown to be a useful method for regenerative medicine in place of stem cell therapy. This study investigated the effects of noncultured SVF transplantation on tooth extraction socket healing in mice. Both chemotherapeutic/bisphosphonate combination therapy for 7 weeks and tooth extraction of maxillary first molars at 3 weeks after drug administration were performed using female C57BL/6J mice. Osseous and soft tissue wound healing were validated at 4 weeks postextraction using gross wound healing and histomorphometry. Here, we created a new animal model of high-prevalence ONJ-like lesions that mimic human progression, because human ONJ mainly occurs in female patients taking both chemotherapeutic and bisphosphonate following tooth extraction. Moreover, mice with chemotherapeutic and bisphosphonate combination therapy for 5 weeks received SVF transplantation just after tooth extraction at 3 weeks post-drug administration. Euthanasia was performed at 2 weeks postextraction to assess the transplantation effects on wound healing using gross wound healing, histomorphometry, immunohistomorphometry, quantitative real-time polymerase chain reaction, and microcomputed tomography. We showed that systemic transplantation of noncultured SVF cells ameliorates ONJ-like lesions by improving both osseous and soft tissue healing of tooth extraction sockets. SVF therapy significantly increased blood vessels and the ratio of M2/M1 macrophages. In addition, SVF transplantation reduced the increases in tartrate-resistant acid phosphatase-positive (TRAP þ ) mononuclear cells (MNCs) and nonattached osteoclasts from the bone surface, which were significantly detected in the connective tissue of tooth extraction sockets and bone marrow by chemotherapeutic/bisphosphonate combination therapy. Our findings suggest that transplantation of noncultured SVF cells is a suitable treatment for BRONJ. Abnormal TRAP þ MNCs and nonattached osteoclasts in systemic and local environments may contribute to the development of BRONJ.

Prevalence of bisphosphonate-related osteonecrosis of the jaw-like lesions is increased in a chemotherapeutic dose-dependent manner in mice

“…ZA monotherapy did not induce BRONJ-like lesions and resulted in normal collagen production, normal PMN infiltration, and similar angiogenesis to VC injection in the connective tissues of tooth extraction sockets. These findings were in accordance with our previous studies [18,30], suggesting that our experimental conditions such as ZA dose, injection duration, administration route, and the timing of tooth extraction do not cause the development of BRONJ-like lesions following tooth extraction. Moreover, the International Task Force on ONJ has agreed that antiangiogenesis does not occur when bisphosphonates are used in animal studies [3].…”

Medication-related osteonecrosis of the jaws after tooth extraction in senescent female mice treated with zoledronic acid: microtomographic, histological and immunohistochemical characterization

“…Namely, the small size of the animal requires reduced amount of the drug, rapid cumulative effects due to rapid mice metabolism, and the possibility of using genetically-manipulated animals to determine a cause-and-effect relationship between the target disruption of a gene and its function [21][22][23]. Several MRONJ models have been developed using mainly C57BL/6 and other mice strains (S1 Table), [15,17,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The C57BL/6 is the most widely used inbred strain and with a large source of genetically modified lines [40].…”

“…The majority of previous studies reported the use of ZA via IP (intraperitoneal) or IV (intravenous) administration as an antiresorptive medication of choice for inducing MRONJ lesions in mice [15,17,24,25,27,29,30,32,33,35,37,39,[42][43][44][45][46], considering its higher potency when compared to other IV or oral nBP's [47]. Moreover, all mouse studies presented in S1 Table were performed in young or adult animals (age varying from 6 to 16 weeks old).…”

Medication‐related osteonecrosis of the jaw‐like lesions in rodents: A comprehensive systematic review and meta‐analysis

“…On the other hand, M2 macrophages, known as wound healing macrophages, are increased in the process of wound repair after invasive surgery . Two studies demonstrated that the M2/M1 ratio in BRONJ‐like lesions was significantly altered after tooth extraction, although they were excluded in this review based on the inclusion and exclusion criteria . Indeed, a human study showed that the ratio of M2/M1 macrophages decreased in BRONJ lesions, suggesting that the discrepant distribution of M1 and M2 macrophages in tooth extraction sockets affected by bisphosphonates is one of the critical mechanisms of BRONJ.…”

“…32 Moreover, significant increase in these cells were significantly reduced with amelioration of BRONJ-like lesions by transplantation of non-cultured stromal vascular cells. 33 Indeed, significant numbers of nonattached osteoclasts were detected in patients taking oral and intravenous bisphosphonates. 34,35 Thus, accumulation of nonattached TRAP-positive cells may contribute to the development of BRONJ, although the working mechanism of increased TRAP-positive cells has not been fully understood.…”