Diphosphonates ; adverse effects ; Humans ; Osteonecrosis ; chemically induced

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse event related to administration of antiresorptive or antiangiogenic medications. With the increasing usage of bone-modifying agents in cancer therapy, the incidence of MRONJ enhanced gradually, which affects the life quality of patients and interferes with cancer therapy. In 2019, Multinational Association of Supportive Care in Cancer (MASCC), International Society of Oral Oncology (ISOO) and American Society of Clinical Oncology (ASCO) convened a multidisciplinary Expert Panel to evaluate the evidence and formulate recommendations on practices in the prevention and management of MRONJ in patients with cancer. The present article made an interpretation of Medication-Related Osteonecrosis of the Jaw: MASCC/ISOO/ASCO Clinical Practice Guideline so as to provide clinicians with diagnostic and therapeutic approaches for cancer patients with MRONJ.
Bisphosphonate-Associated Osteonecrosis of the Jaw/therapy* ; Bone Density Conservation Agents/adverse effects* ; Humans ; Jaw ; Medical Oncology ; Neoplasms/drug therapy* ; Osteonecrosis/chemically induced* ; Quality of Life

OBJECTIVETo establish a new animal model of osteonecrosis of the femoral head by local ethanol injection in emu.

METHODSEight milliliter ethanol was injected slowly to the operated femoral head with customized probe in twenty adult male emus. Postoperatively, hip magnetic resonance imaging was performed at 1, 4, 8, 12 weeks. After emus were sacrificed, the femurs were collected for micro-computed tomography and histological analysis.

RESULTSNo emu demonstrated signs of infection or died unexpectedly. Magnetic resonance imaging examination showed broad edema at proximal femur at 1(th) week, and the edema decreased with time, till local edema at femoral head at the 12(th) week. Histological images showed human-like osteonecrotic changes with active bone repair. There were significant differences in trabecular structure and bone mineral density between the operated and intact femoral heads. No collapse was found 6 months after the operation.

CONCLUSIONSThis emu model of femoral head osteonecrosis by local ethanol injection can progress to early stage osteonecrosis. The different repair methods may have certain correlation with the results of osteonecrosis of the femoral heads.

Animals ; Disease Models, Animal ; Dromaiidae ; Ethanol ; administration & dosage ; toxicity ; Femur Head ; pathology ; Injections ; Male ; Osteonecrosis ; chemically induced

OBJECTIVETo explore the correlation between the dosage of corticosteroid, time of onset and incidence of osteonecrosis (ON) in patients with SARS.

METHODSFrom July 2003 to January 2004, general survey carried out for ON in 551 patients with SARS. Five hundred and fifty-one patients except 12 were administrated by corticosteroid from 80 mg to 30 000 mg. The age of patients was (33 +/- 9) years old ranging from 19 to 59 years old. One hundred and thirty-one were male, and four hundred and twenty were female. MRI and X-ray film were taken in all patients including both hips, knees, shoulders, ankles and wrists. CT scan was taken in partial patients. Common classification system were used for staging of hip (ARCO), knee (Lotka) and shoulder (Cruess). Independent test, rank-sum test and multiple factor logistic regression analysis were used for statistical analysis.

RESULTSNo osteonecrosis was detected in 12 patients without corticosteroid. Osteonecrosis was detected in 176 patients (32.7 percent) among 539 patients. There were ON of femoral head in 130 cases (210 hips), ON of knee in 98 cases (130 knees), ON of humeral head in 21 cases (36 shoulders), ON of talus and calcaneus in 16 cases (26 ankles), ON of scaphoid and lunate in 11 cases (17 wrists), ON of patella in 3 cases (4 patella), ON of ilium in 1 case and bone infarction (femur, tibia) in 18 cases. One hundred and nineteen cases (195 hips) with ONFH were in stage I (IA 45 hips, IB 77 hips, IC 73 hips). Eleven cases (15 hips) were in stage II. All osteonecrosis of the knee and humoral head was stage I. Thirty-four patients with ON had one joint affected, 45 patients had 2 joints, 93 patients had more than 3 joints. The dosage of corticosteroid was (5842 +/- 4988) mg in ON group and (2719 +/- 2571) mg in non-ON group (P < 0.0001). The duration of steroid was (38 +/- 17) d in ON group and (27 +/- 15) d in non-ON group (P < 0.01). The dosage of pulse treatment was (340 +/- 207) mg/d in ON group and (211 +/- 160) mg/d in non-ON group (P < 0.01). The duration of pulse treatment was (28 +/- 13) d in ON group and (18 +/- 11) d in non-ON group (P < 0.01). All patients with ON were detected within 6 months from administration.

CONCLUSIONAbout one-third patients with SARS who were treated with a high dose of corticosteroid occurred osteonecrosis. ON is frequently multiple focuses. The actual time of onset of ON is early of steroid used. MRI is golden standard for early diagnosis of ON. The patients who were treated with a high dose of corticosteroid should be inspected initially by MRI.

Adrenal Cortex Hormones ; administration & dosage ; adverse effects ; Adult ; Early Diagnosis ; Female ; Femur Head Necrosis ; chemically induced ; diagnosis ; epidemiology ; Humans ; Incidence ; Logistic Models ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Osteonecrosis ; chemically induced ; diagnosis ; epidemiology ; Severe Acute Respiratory Syndrome ; drug therapy

BACKGROUNDIn steroid-induced osteonecrosis, hypertrophy and hyperplasia of marrow fat cells and lipid deposition of osteocytes can be found in the femoral head. However, the precise reason is not clear yet. The aim of this study was to observe the effect of dexamethasone (Dex) on differentiation of marrow stromal cells (MSCs), and to investigate the pathobiological mechanism of steroid-induced osteonecrosis.

METHODSMSCs in cultures were treated with increasing concentrations of Dex (0, 10(-9), 10(-8), 10(-7), and 10(-6) mol/L) continuously for 21 days. The cells, which were exposed to 0 mol/L (control) or 10(-7) mol/L Dex for 4 - 21 days, were then cultured for 21 days without Dex. MSCs were stained with Sudan III. Number of adipocytes was counted under a light microscope. The activity of alkaline phosphatase (ALP) of MSCs treated with 0, 10(-8), 10(-7), and 10(-6) mol/L Dex for 12 days, and that treated with 0 mol/L and 10(-7) mol/L Dex for 8, 10, or 12 days were determined. The levels of triglycerides, osteocalcin and cell proliferation of MSCs treated with 0 mol/L and 10(-7) mol/L Dex were detected. The mRNA expression levels of adipose-specific 422 (aP2) gene and osteogenic gene type I collagen in MSCs treated with 0 mol/L and 10(-7) mol/L Dex for 6 days were analyzed by whole-cell dot-blot hybridization. Statistical analysis was performed using Student's t test and analysis of variance. P values less than 0.05 were considered significant statistically.

RESULTSThe number of adipocytes in cultures increased with the duration of MSCs' exposure to Dex and the concentration of Dex. The level of ALP activity in the MSCs decreased with concentration of Dex. In the control group, it was 8.69 times of that in the 10(-7) mol/L Dex group on day 12 (t = 20.51, P < 0.001). The level of triglycerides in 10(-7) mol/L Dex group was 3.40 times of that in the control (t = 11.00, P < 0.001). The levels of cell proliferation and osteocalcin in the control were 1.54 and 2.42 times of that in the 10(-7) mol/L Dex group respectively. As compared to the control, the mRNA expression of adipose-specific 422 (aP2) gene in 10(-7) mol/L Dex group was significantly increased (t = 36.48, P < 0.001), and that of osteogenic gene type I collagen was decreased (t = 42.07, P < 0.001).

CONCLUSIONSDex can directly induce the differentiation of MSCs into a large number of adipocytes and inhibit their osteogenic differentiation, which provide a novel explanation for the pathologic changes of steroid-induced osteonecrosis.

Adipogenesis ; drug effects ; Alkaline Phosphatase ; metabolism ; Animals ; Bone Marrow Cells ; cytology ; drug effects ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Dexamethasone ; toxicity ; Female ; Mice ; Osteocalcin ; genetics ; Osteonecrosis ; chemically induced ; RNA, Messenger ; analysis ; Radioimmunoassay ; Stromal Cells ; cytology

Osteoporosis is a major, growing healthcare issue. This is especially of concern in an ageing population like that of Singapore. Osteoporotic patients are at risk of fractures, which can result in increased morbidity and mortality. The use of antiresorptive therapy with bisphosphonates or denosumab has been proven to reduce fracture risk. However, the use of these medications has rarely been associated with the development of osteonecrosis of the jaw, a potentially debilitating condition affecting one or both jaws. Appropriate understanding of the patient's antiresorptive therapy regime, as well as early institution of preventive dental measures, can play an important role in preventing medication-related osteonecrosis of the jaw (MRONJ). Regular monitoring and prompt referral to specialist care is warranted for patients with established MRONJ.
Aged ; Bone Density Conservation Agents ; adverse effects ; therapeutic use ; Denosumab ; adverse effects ; therapeutic use ; Diphosphonates ; adverse effects ; therapeutic use ; Humans ; Jaw Diseases ; chemically induced ; prevention & control ; Osteonecrosis ; chemically induced ; prevention & control ; Osteoporosis ; complications ; drug therapy ; Osteoporotic Fractures ; complications ; drug therapy ; Risk Factors ; Singapore ; Treatment Outcome

Osteonecrosis of the femoral head is frequently observed in patients treated with excessive corticosteroids. However, the pathogenesis of corticosteroid-induced osteonecrosis remains unclear. The purpose of this study was to investigate the role of Toll-like receptor 4 (TLR4) signaling pathway in steroid-induced femoral head osteonecrosis in rats. Male Sprague-Dawley rats were injected intramuscularly with 20 mg/kg methylprednisolone (MP) for 8 weeks, twice per week. The animals were sacrificed at 2, 4 and 8 weeks after the last MP injection, respectively, and then allocated to the 2-, 4- and 8-week model groups (n=24 each). Rats in the control group (n=12) were not given any treatment. Histopathological analysis was performed and the concentration of tartrate-resistant acid phosphatase (TRAP) in plasma was determined. The activation of osteoclasts in the femoral head was assessed by TRAP staining. The expression of TLR4, MyD88, TRAF6 and NF-κB p65 that are involved in TLR4 signaling, and MCP-1 production were detected by using real-time PCR (RT-PCR) and Western blotting. The results showed that the osteonecrosis in the femoral head was clearly observed and the concentration of TRAP in the plasma was increased in the model rats. The femoral head tissues in MP-treated rats were positive for TRAP and the intensity of TRAP staining was greater in MP-treated rats than in control rats. As compared with the control group, the mRNA expression of TLR4 signaling-related factors was enhanced significantly at 4 and 8 weeks, and the protein levels of these factors increased significantly with time. It was concluded that MP could induce the femoral head osteonecrosis in rats, which was associated with osteoclast activation via the TLR4 signaling pathway. These findings suggest that TLR4 signaling pathway plays a pivotal role in the pathogenesis of steroid-induced osteonecrosis.
Acid Phosphatase ; metabolism ; Animals ; Blotting, Western ; Chemokine CCL2 ; genetics ; metabolism ; Femur Head ; metabolism ; pathology ; Gene Expression ; Immunohistochemistry ; Isoenzymes ; metabolism ; Male ; Methylprednisolone ; Myeloid Differentiation Factor 88 ; genetics ; metabolism ; Osteonecrosis ; chemically induced ; genetics ; metabolism ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; TNF Receptor-Associated Factor 6 ; genetics ; metabolism ; Tartrate-Resistant Acid Phosphatase ; Time Factors ; Toll-Like Receptor 4 ; genetics ; metabolism ; Transcription Factor RelA ; genetics ; metabolism