Damage and recovery of the bone growth mechanism in young rats following 5-fluorouracil acute chemotherapy

Effect of chemotherapy and different chemotherapy regimens on bone health among Chinese breast cancer women in different menstrual status: a self-control study

PURPOSE

Although the therapy-related bone loss attracts increasing attention nowadays, the differences in chemotherapy-induced bone loss and bone metabolism indexes change among breast cancer (BC) women with different menstrual statuses or chemotherapy regimens are unknown. The aim of the study is to explore the effects of different regimens of chemotherapy on bone health.

METHOD

The self-control study enrolled 118 initially diagnosed BC women without distant metastasis who underwent dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) screening and (or) bone metabolism index monitoring during chemotherapy at Chongqing Breast Cancer Center. Mann-Whitney U test, Cochran's Q test, and Wilcoxon sign rank test were performed.

RESULTS

After chemotherapy, the BMD in the lumbar 1-4 and whole lumbar statistically decreased (- 1.8%/per 6 months), leading to a significantly increased proportion of osteoporosis (27.1% vs. 20.5%, P < 0.05), which were mainly seen in the premenopausal group (- 7.0%/per 6 months). Of the chemotherapeutic regimens of EC (epirubicin + cyclophosphamide), TC (docetaxel + cyclophosphamide), TEC (docetaxel + epirubicin + cyclophosphamide), and EC-T(H) [epirubicin + cyclophosphamide-docetaxel and/or trastuzumab], EC regimen had the least adverse impact on BMD, while the EC-TH regimen reduced BMD most (P < 0.05) inspite of the non-statistical difference between EC-T regimen, which was mainly seen in the postmenopausal group. Chemotherapy-induced amenorrhea (estradiol 94 pg/ml vs, 22 pg/ml; FSH 9.33 mIU/ml vs. 61.27 mIU/ml) was proved in premenopausal subgroup (P < 0.001). Except the postmenopausal population with calcium/VitD supplement, the albumin-adjusted calcium increased significantly (2.21 mmol/l vs. 2.33 mmol/l, P < 0.05) after chemotherapy. In postmenopausal group with calcium/VitD supplement, β-CTX decreased significantly (0.56 ng/ml vs. 0.39 ng/ml, P < 0.05) and BMD were not affected by chemotherapy (P > 0. 05). In premenopausal group with calcium/VitD supplement, PTH decreased significantly (52.90 pg/ml vs. 28.80 pg/ml, P = 0. 008) and hip BMD increased after chemotherapy (0.845 g/m2 vs. 0.952 g/m2, P = 0. 006). As for both postmenopausal and premenopausal group without calcium/VitD supplement, there was a significant decrease in bone mass in hip and lumbar vertebrae after chemotherapy (0.831 g/m2 vs. 0.776 g/m2; 0.895 g/m2 vs. 0.870 g/m2, P < 0.05).

CONCLUSION

Chemotherapy might induce lumbar vertebrae BMD loss and spine osteoporosis with regimen differences among Chinese BC patients. Calcium/VitD supplementation could improve bone turnover markers, bone metabolism indicators, and bone mineral density. Early interventions on bone health are needed for BC patients during chemotherapy.

Skeletal effects following developmental flame-retardant exposure are specific to sex and chemical class in the adult Wistar rat

Introduction: Accumulating evidence reveals that endocrine disrupting chemicals (EDCs) can disrupt aspects of metabolic programming, suggesting that skeletal development may be at risk, a possibility that is rarely examined. The commercial flame retardant (FR) mixture, Firemaster 550 (FM 550), has repeatedly been shown to negatively influence metabolic programming, raising concerns that skeletal integrity may consequently be impaired. We have previously shown that gestational and lactational exposure to 1,000 µg FM 550 negatively affected sex-specific skeletal traits in male, but not female, rats assessed at 6 months of age. Whether this outcome is primarily driven by the brominated (BFR) or organophosphate ester (OPFR) portions of the mixture or the effects persist to older ages is unknown. Materials and methods: To address this, in the present study, dams were orally exposed throughout gestation and lactation to either 1,000 μg BFR, 1,000 µg OPFR, or 2,000 µg FM 550. Offspring (n = 8/sex/exposure) were weaned at PND 21 and assessed for femoral cortical and trabecular bone parameters at 8 months of age by high-resolution X-ray micro-computed tomography (micro-CT). Serum levels of serotonin, osteocalcin, alkaline phosphatase, and calcium were quantified. Results: FM 550 affected both sexes, but the females were more appreciably impacted by the OPFRs, while the males were more vulnerable to the BFRs. Conclusion: Although sex specificity was expected due to the sexual dimorphic nature of skeletal physiology, the mechanisms accounting for the male- and female-specific phenotypes remain to be determined. Future work aims to clarify these unresolved issues.

The influence of antineoplastic agents on the peri-implant bone around osseointegrated titanium implants: an in vivo histomorphometric and immunohistochemical study

BACKGROUND AND OBJECTIVE

The interaction between antineoplastic drugs used for treating cancer and non-affected tissues remains poorly assessed and may be critical for maintaining the quality of life for patients during and after treatment. This pre-clinical study evaluated the effects of cisplatin (CIS) and 5-fluorouracil (5-FU) on the peri-implant repair process around osseointegrated titanium implants installed in the tibiae of rats.

MATERIAL AND METHODS

Were used 90 male rats, randomly divided into three groups (n = 30): physiological saline solution (PSS), CIS, and 5-FU. Titanium implants (4.0 × 2.2 mm) were inserted in both tibiae of all animals at day 0. The animals received either PSS, CIS, or 5-FU at 35 and 37 days. Euthanasia was performed at 50, 65, and 95 days after surgery. Histometric (bone/implant contact [BIC]) and bone area fraction occupancy (% BAFO), histological, and immunohistochemical (for bone morphogenetic protein 2/4 [BMP2/4], Runt-related transcription factor 2 [RUNX2], osteocalcin [OCN], and tartrate-resistant acid phosphatase [TRAP]) analyses were performed. Data were statistically analyzed.

RESULTS

Groups CIS and 5-FU presented lower BIC and lower BAFO as compared with PSS in all time points. The imbalance in bone turnover was observed by the lower number of BMP2/4-, RUNX2-, and OCN-positive cells/mm2 and the higher number of TRAP-positive cells/mm in groups CIS and 5-FU as compared with PSS in all time points. Persistent and exacerbated inflammation was observed in groups CIS and 5-FU.

CONCLUSIONS

Both antineoplastic agents interfered negatively in the bone turnover around osseointegrated titanium implants.

CLINICAL RELEVANCE

Closer and more careful follow-up of patients with osseointegrated implants that will undergo chemotherapy with either CIS or 5-FU shall be performed.

Novel doxorubicin / folate-targeted trans-ferulic acid-loaded PLGA nanoparticles combination: In-vivo superiority over standard chemotherapeutic regimen for breast cancer treatment

AIM

Doxorubicin/Cyclophosphamide (AC) is one of the standard adjuvant anthracycline-containing regimens that is still in use for breast cancer treatment. Cancer cell resistance and AC-induced side effects make treatment suboptimal and worsen patients' quality of life. This study aimed to improve trans-ferulic acid's (TFA) efficiency via loading into folate-receptor-targeted-poly lactic-co-glycolic acid nanoparticles (FA-PLGA-TFA NPs). Also, investigating both the antitumor efficacy of Doxorubicin (Dox)/FA-PLGA-TFA NPs combination against dimethylbenz[a]anthracene (DMBA)-induced breast cancer and its safety profile.

METHODS

FA-PLGA-TFA NPs were optimally fabricated and characterized. Levels of Notch1, Hes1, Wnt-3a, β-catenin, MMP-9, cyclin D1, Permeability-Glycoprotein (P-gp), ERα, PR, and HER2 were assessed as a measure of the antitumor efficacy of different treatment protocols. Histopathological examination of heart and bone, levels of ALT, AST, ALP, CK-MB, and WBCs count were evaluated to ensure the combination's safety profile.

KEY FINDINGS

Dox/FA-PLGA-TFA NPs not only inhibited Notch signaling but also suppressed Notch synergy with Wnt, estrogen, progesterone, and HER2 pathways. Interestingly, Dox/FA-PLGA-TFA NPs decreased P-gp level and preserved heart, bone, and liver health as well as WBCs count.

SIGNIFICANCE

Dox/FA-PLGA-TFA NPs reduced the side-effects of each single drug, and at the same time exerted excellent antitumor activity that surpass the AC regimen in evading cancer cell resistance and having a superior safety profile.

Antineoplastic agents aggravate the damages caused by nicotine on the peri-implant bone: an in vivo histomorphometric and immunohistochemical study in rats

OBJECTIVE

To assess the interaction between chemotherapy and normal tissues is critical to assure quality of life during and after the treatment of cancer. This study evaluated the influence of cisplatin (CIS) and 5-fluorouracil (5-FU) over the peri-implant tissues around osseointegrated titanium implants in animals previously exposed to nicotine. Materials and methods One hundred twenty male rats were divided into two groups, receiving via subcutaneous injection, either physiological saline solution (PSS) (n = 30) or nicotine hemissulfate (NIC) (n = 90) for 30 days prior to implants' placement. One titanium implant (4.0 × 2.2 mm) was installed in each tibia of all animals. PSS and NIC were continued for 30 days after surgery. Five days after cessation, rats were subdivided into three subgroups in accordance with systemic treatments with either PSS, CIS, or 5-FU. Euthanasia was performed at 50, 65, and 95 days post-surgery. Histometric, histopathological, and immunohistochemical analyses were performed.

RESULTS

NIC-CIS and NIC-5FU presented lower BIC (50, 65, and 95 days) and bone area fraction occupancy (BAFO) (65 and 95 days) than group NIC. Intense inflammatory infiltration, severe tissue breakdown, reduced expression of bone formation biomarkers, and upregulation of TRAP were observed in NIC-CIS and NIC-5FU when compared with group NIC. TRAP expression was significantly higher in NIC-5FU as compared with NIC-CIS at 50 and 95 days. Groups NIC, NIC-CIS, and NIC-5FU presented statistically significant negative impact in all outcome parameters than group PSS.

CONCLUSION

CIS and 5-FU severely disrupted the peri-implant tissues around osseointegrated implants in animals previously exposed to nicotine.

CLINICAL RELEVANCE

Assessing the interaction between chemotherapy and normal tissues is critical to assure quality of life during and after the cancer treatment.

Effect of cytotoxic chemotherapy on bone health among breast cancer patients. Does it require intervention?

BACKGROUND

Breast cancer (BC) is one of the most common malignancies worldwide. Although the burden and mechanisms of endocrine therapy-related bone loss are known, the evidence is scanty regarding the impact of cytotoxic chemotherapy on bone health. We have attempted to summarize the effect of cytotoxic chemotherapy on bone health in BC patients.

METHODS

A comprehensive literature search was performed via MEDLINE and Cochrane library databases to evaluate the effect of chemotherapy on bone health among women with BC. We included articles related to skeletal-related events, bone mineral density, bone turnover markers, osteoporosis-specific quality of life, bisphosphonate, and other bone-directed therapy. We excluded articles that included patients with metastatic breast cancer and patients receiving hormonal therapy.

DISCUSSION

Bone microenvironment in cancer is directly or indirectly influenced by clinical, hormonal, nutritional, and treatment factors. Calcitonin, parathyroid hormone, calcitriol, and estrogen are the major hormonal regulators. Bone turnover markers, namely bone formation and resorption markers, have been used to predict bone loss, fracture risk, and monitoring treatment response. Chemotherapeutic drugs such as anthracyclines and taxanes synergistically affect BMD and quality of life. Calcium, vitamin D, bisphosphonates, and denosumab are supplemented to prevent excess bone resorption. Bone-targeted anti-resorptive agents have been studied as potential anticancer agents in the adjuvant treatment of breast cancer.

CONCLUSION

This review summarizes the negative effect of chemotherapy on bone health of BC patients and the importance of preventing or treating bone loss.

β-Catenin signaling is important for osteogenesis and hematopoiesis recovery following methotrexate chemotherapy in rats

Cancer chemotherapy can significantly impair the bone formation and cause myelosuppression; however, their recovery potentials and mechanisms remain unclear. This study investigated the roles of the β-catenin signaling pathway in bone and bone marrow recovery potentials in rats treated with antimetabolite methotrexate (MTX) (five once-daily injections, 0.75 mg/kg) with/without β-catenin inhibitor indocyanine green (ICG)-001 (oral, 200 mg/kg/day). ICG alone reduced trabecular bone volume and bone marrow cellularity. In MTX-treated rats, ICG suppressed bone volume recovery on Day 11 after the first MTX injection. ICG exacerbated MTX-induced decreases on Day 9 osteoblast numbers on bone surfaces, their formation in vitro from bone marrow stromal cells (osteogenic differentiation/mineralization), as well as expression of osteogenesis-related markers Runx2, Osx, and OCN in bone, and it suppressed their subsequent recoveries on Day 11. On the other hand, ICG did not affect MTX-induced increased osteoclast density and the level of the osteoclastogenic signal (RANKL/OPG expression ratio) in bone, suggesting that ICG inhibition of β-catenin does nothing to abate the increased bone resorption induced by MTX. ICG also attenuated bone marrow cellularity recovery on Day 11, which was associated with the suppressed recovery of CD34⁺ or c-Kit⁺  hematopoietic progenitor cell contents. Thus, β-catenin signaling is important for osteogenesis and hematopoiesis recoveries following MTX chemotherapy.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Release of CXCL12 From Apoptotic Skeletal Cells Contributes to Bone Growth Defects Following Dexamethasone Therapy in Rats

Dexamethasone (Dex) is known to cause significant bone growth impairment in childhood. Although previous studies have suggested roles of osteocyte apoptosis in the enhanced osteoclastic recruitment and local bone loss, whether it is so in the growing bone following Dex treatment requires to be established. The current study addressed the potential roles of chemokine CXCL12 in chondroclast/osteoclast recruitment and bone defects following Dex treatment. Significant apoptosis was observed in cultured mature ATDC5 chondrocytes and IDG-SW3 osteocytes after 48 hours of 10^-6  M Dex treatment, and CXCL12 was identified to exhibit the most prominent induction in Dex-treated cells. Conditioned medium from the treated chondrocytes/osteocytes enhanced migration of RAW264.7 osteoclast precursor cells, which was significantly inhibited by the presence of the anti-CXCL12 neutralizing antibody. To investigate the roles of the induced CXCL12 in bone defects caused by Dex treatment, young rats were orally gavaged daily with saline or Dex at 1 mg/kg/day for 2 weeks, and received an intraperitoneal injection of anti-CXCL12 antibody or control IgG (1 mg/kg, three times per week). Aside from oxidative stress induction systemically, Dex treatment caused reductions in growth plate thickness, primary spongiosa height, and metaphysis trabecular bone volume, which are associated with induced chondrocyte/osteocyte apoptosis and enhanced chondroclast/osteoclast recruitment and osteoclastogenic differentiation potential. CXCL12 was induced in apoptotic growth plate chondrocytes and metaphyseal bone osteocytes. Anti-CXCL12 antibody supplementation considerably attenuated Dex-induced chondroclast/osteoclast recruitment and loss of growth plate cartilage and trabecular bone. CXCL12 neutralization did not affect bone marrow osteogenic potential, adiposity, and microvasculature. Thus, CXCL12 was identified as a potential molecular linker between Dex-induced skeletal cell apoptosis and chondroclastic/osteoclastic recruitment, as well as growth plate cartilage/bone loss, revealing a therapeutic potential of CXCL12 functional blockade in preventing bone growth defects during/after Dex treatment. © 2018 American Society for Bone and Mineral Research.

Characterization of 5-Fluorouracil Daily Oral Dosing versus Dietary Restriction on Femoral Growth Plates in Rats

We evaluated the growth plates (GPs) of rats after a 14-day reduction in food consumption caused by either daily oral dosing with 5-fluorouracil (5-FU: a positive control reducing food consumption and affecting the GPs) or a direct reduction in food consumption to determine whether the observed changes were attributable to a direct effect of drug toxicity. Histomorphometric analyses of the femoral GP were performed for a nontreated (NT) control group, three groups treated with 5-FU (12, 15, and 18 mg/kg/day) and three groups with food intake restricted to levels corresponding to those consumed by the rats in the three 5-FU-treated groups. Compared with the NT group, the GP widths and the number of chondrocytes in the proliferative zone decreased significantly in all the 5-FU-treated groups and the dietary restriction groups. Importantly, no significant differences between the 5-FU-treated groups and the groups with matched dietary restrictions were seen for most parameters. Thus, the 14-day dietary restriction caused significant changes in the proliferative zone of the GP, and similar changes observed in the 5-FU-treated groups were presumed to result from the comparable reduction in food intake rather than being a direct toxic effect of the drug.

Individual or combination treatments with lapatinib and paclitaxel cause potential bone loss and bone marrow adiposity in rats

Cancer treatments with cytotoxic drugs have been shown to cause bone loss. However, effects on bone are less clear for ErbB-targeting tyrosine kinase inhibitors or their combination use with cytotoxic drugs. This study examined the effects of individual or combination treatments with breast cancer drugs lapatinib (a dual ErbB1/ErbB2 inhibitor) and paclitaxel (a microtubule-stabilizing cytotoxic agent) on bone and bone marrow of rats. Wistar rats received lapatinib (240 mg/kg) daily, paclitaxel (12 mg/kg) weekly, or their combination for 4 weeks, and effects on bone/bone marrow were examined at the end of week 4. Microcomputed tomographical structural analyses showed a reduction in trabecular bone volume in tibia following the lapatinib, paclitaxel or their combination treatments ( P < 0.05). Histomorphometry analyses revealed marked increases in bone marrow adipocyte contents in all treatment groups. Reverse transcription polymerase chain reaction gene expression studies with bone samples and cell culture studies with isolated bone marrow stromal cells showed that the all treatment groups displayed significantly reduced levels of osterix expression and osteogenic differentiation potential but increased expression levels of adipogenesis transcription factor peroxisome proliferator-activated receptor γ. In addition, these treatments suppressed the expression of Wnt10b and/or increased expression of Wnt antagonists (secreted frizzled-related protein 1, Dickkopf-related protein 1 and/or sclerostin). Furthermore, all treatment groups showed increased numbers of bone-resorbing osteoclasts on trabecular bone surfaces, although only the lapatinib group displayed increased levels of osteoclastogenic signal (receptor activator of nuclear factor κΒ ligand/osteoclastogenesis inhibitor osteoprotegrin expression ratio) in the bones. Thus, inhibiting ErbB1 and ErbB2 by lapatinib or blocking cell division by paclitaxel or their combination causes significant trabecular bone loss and bone marrow adiposity involving a switch in osteogenesis/adipogenesis potential, altered expression of some major molecules of the Wnt/β-catenin signalling pathway, and increased recruitment of bone-resorbing osteoclasts.

Osteoporosis and fracture after gastrectomy for stomach cancer: A nationwide claims study

This study was planned to evaluate the incidence and risk factors of osteoporosis and fracture after gastrectomy for stomach cancer using a nationwide claims database in South Korea.Data from 41,512 patients (50-79 years) who underwent gastrectomy for stomach cancer from 2008 to 2010 with at least 5 years of follow-up were obtained from the Health Insurance Review and Assessment Service database. Patients diagnosed with osteoporosis and prescribed bisphosphonate or raloxifene or who experienced osteoporotic fractures after gastrectomy were operationally defined as osteoporosis. Osteoporotic fracture was defined as a fracture at common osteoporotic fracture sites (spine, pelvis, hip, forearm, or rib).In total, 37,076 patients were included in the final analysis. The incidences of postgastrectomy osteoporosis and osteoporotic fractures were 41.9 and 27.6 cases per 1000 person-years, respectively. Multivariate analysis showed that older age (hazard ratio [HR] 1.88; 95% confidence interval [CI] 1.79-1.96), female gender (HR 2.46; 2.35-2.58), total gastrectomy (HR 1.10; 1.04-1.16), and diabetes (HR 1.16; 1.11-1.22) were significantly associated with osteoporosis and that older age (HR 1.90; 95% CI 1.80-2.01), female gender (HR 1.50; 1.41-1.58), total gastrectomy (HR 1.17; 1.10-1.25), chemotherapy (HR 1.06; 1.00-1.12), and diabetes (HR 1.26; 1.19-1.33) were significantly associated with fractures. Osteoporotic fractures occurred a median 3.1 years after gastrectomy. Among the 5175 fracture patients, 780 (15.1%) experienced multisite fractures, mostly in the elderly and chemotherapy groups.The osteoporosis and osteoporotic fracture incidences are high in patients within a relatively short timeframe after gastrectomy for stomach cancer. Systematic management of osteoporosis is necessary after this surgery.

Long Chain Omega-3 Polyunsaturated Fatty Acid Supplementation Protects Against Adriamycin and Cyclophosphamide Chemotherapy-Induced Bone Marrow Damage in Female Rats

Although bone marrow and bone toxicities have been reported in breast cancer survivors, preventative strategies are yet to be developed. Clinical studies suggest consumption of long chain omega-3 polyunsaturated fatty acids (LCn3PUFA) can attenuate age-related bone loss, and recent animal studies also revealed benefits of LCn3PUFA in alleviating bone marrow and bone toxicities associated with methotrexate chemotherapy. Using a female rat model for one of the most commonly used anthracycline-containing breast cancer chemotherapy regimens (adriamycin + cyclophosphamide) (AC) chemotherapy, this study investigated potential effects of daily LCn3PUFA consumption in preserving bone marrow and bone microenvironment during chemotherapy. AC treatment for four cycles significantly reduced bone marrow cellularity and increased marrow adipocyte contents. It increased trabecular bone separation but no obvious changes in bone volume or bone cell densities. LCn3PUFA supplementation (375 mg/100 g/day) attenuated AC-induced bone marrow cell depletion and marrow adiposity. It also partially attenuated AC-induced increases in trabecular bone separation and the cell sizes and nuclear numbers of osteoclasts formed ex vivo from bone marrow cells isolated from AC-treated rats. This study suggests that LCn3PUFA supplementation may have beneficial effects in preventing bone marrow damage and partially protecting the bone during AC cancer chemotherapy.

Low-level laser and antimicrobial photodynamic therapy on experimental periodontitis in rats submitted to chemotherapy by 5-fluorouracil

PURPOSE

The aim of this study was to evaluate the effects of low-level laser therapy (LLLT) and antimicrobial photodynamic therapy (aPDT) as adjuvant to mechanical treatment of experimental periodontitis (EP) in adult rats submitted to 5-fluorouracil (5-FU) chemotherapy.

METHODS

EP was induced through ligature around the left mandibular first molar for 7 days. The ligature was removed and the animals separated into groups: EP, no treatment; 5FU, systemic administration of 5-FU (80 and 40 mg/kg); 5FU/scaling and root planing (SRP), systemic application of 5-FU and SRP; 5FU/SRP/LLLT, systemic application of 5-FU, SRP, and LLLT (660 nm, 0.035 W; 29.4 J/cm²); and 5FU/SRP/aPDT, systemic application of 5-FU, SRP, and aPDT (methylene blue irrigation and LLLT). The animals were euthanized 7, 15, and 30 days after treatments. Histological sections from mandibles were processed for histomorphometric and immunohistochemical analysis (TRAP, RANKL, OPG, TNF-α, IL-6, IL-10). The alveolar bone loss (BL) area in the furcation region of the mandibular first molar was analyzed histometrically.

RESULTS

There was less bone loss in 5FU/SRP/aPDT compared with 5FU at 7 days (p < 0.05). The immunohistochemical analysis showed no significant difference for TRAP and osteoprotegerin, but lower RANKL immunolabeling was observed in the 5FU/SRP/LLLT and 5FU/SRP/aPDT groups compared with the 5FU group at 15 days. There was lower TNF-α and IL-6 immunolabeling in the 5FU/SRP/LLLT and 5FU/SRP/aPDT groups and higher IL-10 immunolabeling in 5FU/SRP/aPDT at 30 days.

CONCLUSION

LLLT and aPDT adjuvant to SRP minimized the effects of 5-FU on periodontal disease. Furthermore, aPDT promoted greater benefits in bone loss control and inflammatory response.

Genetically engineered flavonol enriched tomato fruit modulates chondrogenesis to increase bone length in growing animals

Externally visible body and longitudinal bone growth is a result of proliferation of chondrocytes. In growth disorder, there is delay in the age associated increase in height. The present study evaluates the effect of extract from transgenic tomato fruit expressing AtMYB12 transcription factor on bone health including longitudinal growth. Constitutive expression of AtMYB12 in tomato led to a significantly enhanced biosynthesis of flavonoids in general and the flavonol biosynthesis in particular. Pre-pubertal ovary intact BALB/c mice received daily oral administration of vehicle and ethanolic extract of wild type (WT-TOM) and transgenic AtMYB12-tomato (MYB12-TOM) fruits for six weeks. Animal fed with MYB12-TOM showed no inflammation in hepatic tissues and normal sinusoidal Kupffer cell morphology. MYB12-TOM extract significantly increased tibial and femoral growth and subsequently improved the bone length as compared to vehicle and WT-TOM. Histomorphometry exhibited significantly wider distal femoral and proximal tibial growth plate, increased number and size of hypertrophic chondrocytes in MYB12-TOM which corroborated with micro-CT and expression of BMP-2 and COL-10, marker genes for hypertrophic cells. We conclude that metabolic reprogramming of tomato by AtMYB12 has the potential to improve longitudinal bone growth thus helping in achievement of greater peak bone mass during adolescence.

Knee loading protects against osteonecrosis of the femoral head by enhancing vessel remodeling and bone healing

Osteonecrosis of the femoral head is a serious orthopedic problem. Moderate loads with knee loading promote bone formation, but their effects on osteonecrosis have not been investigated. Using a rat model, we examined a hypothesis that knee loading enhances vessel remodeling and bone healing through the modulation of the fate of bone marrow-derived cells. In this study, osteonecrosis was induced by transecting the ligamentum teres followed by a tight ligature around the femoral neck. For knee loading, 5 N loads were laterally applied to the knee at 15 Hz for 5 min/day for 5 weeks. Changes in bone mineral density (BMD) and bone mineral content (BMC) of the femur were measured by pDEXA, and ink infusion was performed to evaluate vessel remodeling. Femoral heads were harvested for histomorphometry, and bone marrow-derived cells were isolated to examine osteoclast development and osteoblast differentiation. The results showed that osteonecrosis significantly induced bone loss, and knee loading stimulated both vessel remodeling and bone healing. The osteonecrosis group exhibited the lowest trabecular BV/TV (p b 0.001) in the femoral head, and lowest femoral BMD and BMC (both p b 0.01). However, knee loading increased trabecular BV/TV (p b 0.05) as well as BMD (pb 0.05) and BMC (p b 0.01). Osteonecrosis decreased the vessel volume (pb 0.001), vessel number (pb 0.001) and VEGF expression (p b 0.01), and knee loading increased them (pb 0.001, pb 0.001 and p b 0.01). Osteonecrosis activated osteoclast development, and knee loading reduced its formation, migration, adhesion and the level of “pit” formation (pb 0.001, pb 0.01, pb 0.001 and pb 0.001). Furthermore, knee loading significantly increased osteoblast differentiation and CFU-F (both p b 0.001). A significantly positive correlation was observed between vessel remodeling and bone healing (both p b 0.01). These results indicate that knee loading could be effective in repair osteonecrosis of the femoral head in a rat model. This effect might be attributed to promoting vessel remodeling, suppressing osteoclast development, and increasing osteoblast and fibroblast differentiation. In summary, the current study suggests that knee loading might potentially be employed as a non-invasive therapy for osteonecrosis of the femoral head.

Effects of manganese deficiency on the microstructure of proximal tibia and OPG/RANKL gene expression in chicks

Manganese (Mn) deficiency can result in perosis in chicks, but the mechanism of Mn deficiency on tibia development remains poorly understood. Ninety one-day-old Arbor Acres male broiler chickens administered with control diet (60 mg Mn/kg) and Mn-deficient diets (40 mg Mn/kg, 8.7 mg Mn/kg) to investigate the effects of Mn deficiency on morphology of tibia and related signal transduction pathways in broiler chickens. At the age of 42 days, the bone trabecula, damaged osteoblasts and OPG/RANKL mRNA expression levels were investigated by histological assessment, electron microscopic examination and real-time quantitative PCR analysis, respectively. Results of histological observations showed that decreased trabecular thickness, trabecular number and trabecular bone area (%) together with increased trabecular bone separation were involved in perosis induced by Mn deficiency. The most striking ultrastructural modifications involved disruption of nuclear membrane and mitochondria outer membrane, loss of mitochondrion cristae and alteration in endoplasmic reticulum in osteoblasts of the Mn-deficient groups. Likewise, Mn deficiency results in a significant (P < 0.05) decrease in the relative mRNA expression levels of OPG and RANKL with a significantly higher RANKL/OPG ratio (P < 0.05). In conclusion, Mn deficiency can affect the development of tibia in broiler chickens, leading to metaphyseal osteoporosis which may be due to decreased OPG/RANKL mRNA expression.

Effects of resveratrol supplementation on bone growth in young rats and microarchitecture and remodeling in ageing rats

Osteoporosis is a highly prevalent skeletal disorder in the elderly that causes serious bone fractures. Peak bone mass achieved at adolescence has been shown to predict bone mass and osteoporosis related risk fracture later in life. Resveratrol, a natural polyphenol compound, may have the potential to promote bone formation and reduce bone resorption. However, it is unclear whether it can aid bone growth and bone mass accumulation during rapid growth and modulate bone metabolism during ageing. Using rat models, the current study investigated the potential effects of resveratrol supplementation during the rapid postnatal growth period and in late adulthood (early ageing) on bone microarchitecture and metabolism. In the growth trial, 4-week-old male hooded Wistar rats on a normal chow diet were given resveratrol (2.5 mg/kg/day) or vehicle control for 5 weeks. In the ageing trial, 6-month-old male hooded Wistar rats were treated with resveratrol (20 mg/kg/day) or vehicle for 3 months. Treatment effects in the tibia were examined by μ-computer tomography (μ-CT) analysis, bone histomorphometric measurements and reverse transcription-polymerase chain reaction (RT-PCR) gene expression analysis. Resveratrol treatment did not affect trabecular bone volume and bone remodeling indices in the youth animal model. Resveratrol supplementation in the early ageing rats tended to decrease trabecular bone volume, Sirt1 gene expression and increased expression of adipogenesis-related genes in bone, all of which were statistically insignificant. However, it decreased osteocalcin expression (p = 0.03). Furthermore, serum levels of bone resorption marker C-terminal telopeptides type I collagen (CTX-1) were significantly elevated in the resveratrol supplementation group (p = 0.02) with no changes observed in serum levels of bone formation marker alkaline phosphatase (ALP). These results in rat models suggest that resveratrol supplementation does not significantly affect bone volume during the rapid growth phase but may potentially have negative effects on male skeleton during early ageing.

Widespread differential maternal and paternal genome effects on fetal bone phenotype at mid-gestation

Parent-of-origin-dependent (epi)genetic factors are important determinants of prenatal development that program adult phenotype. However, data on magnitude and specificity of maternal and paternal genome effects on fetal bone are lacking. We used an outbred bovine model to dissect and quantify effects of parental genomes, fetal sex, and nongenetic maternal effects on the fetal skeleton and analyzed phenotypic and molecular relationships between fetal muscle and bone. Analysis of 51 bone morphometric and weight parameters from 72 fetuses recovered at day 153 gestation (54% term) identified six principal components (PC1-6) that explained 80% of the variation in skeletal parameters. Parental genomes accounted for most of the variation in bone wet weight (PC1, 72.1%), limb ossification (PC2, 99.8%), flat bone size (PC4, 99.7%), and axial skeletal growth (PC5, 96.9%). Limb length showed lesser effects of parental genomes (PC3, 40.8%) and a significant nongenetic maternal effect (gestational weight gain, 29%). Fetal sex affected bone wet weight (PC1, p < 0.0001) and limb length (PC3, p < 0.05). Partitioning of variation explained by parental genomes revealed strong maternal genome effects on bone wet weight (74.1%, p < 0.0001) and axial skeletal growth (93.5%, p < 0.001), whereas paternal genome controlled limb ossification (95.1%, p < 0.0001). Histomorphometric data revealed strong maternal genome effects on growth plate height (98.6%, p < 0.0001) and trabecular thickness (85.5%, p < 0.0001) in distal femur. Parental genome effects on fetal bone were mirrored by maternal genome effects on fetal serum 25-hydroxyvitamin D (96.9%, p < 0.001) and paternal genome effects on alkaline phosphatase (90.0%, p < 0.001) and their correlations with maternally controlled bone wet weight and paternally controlled limb ossification, respectively. Bone wet weight and flat bone size correlated positively with muscle weight (r = 0.84 and 0.77, p < 0.0001) and negatively with muscle H19 expression (r = -0.34 and -0.31, p < 0.01). Because imprinted maternally expressed H19 regulates growth factors by miRNA interference, this suggests muscle-bone interaction via epigenetic factors.

Fish oil in comparison to folinic acid for protection against adverse effects of methotrexate chemotherapy on bone

Methotrexate (MTX) chemotherapy is known to cause bone loss which lacks specific preventative treatments, although clinically folinic acid is often used to reduce MTX toxicity in soft tissues. This study investigated damaging effects of MTX injections (0.75 mg/kg/day for 5 days) in rats and potential protective benefits of fish oil (0.25, 0.5, or 0.75 ml/100 g/day) in comparison to folinic acid (0.75 mg/kg) in the tibial metaphysis. MTX treatment significantly reduced height of primary spongiosa and volume of trabecular bone while reducing density of osteoblasts. Consistently, MTX reduced osteogenic differentiation but increased adipogenesis of bone marrow stromal cells, accompanied by lower mRNA expression of osteogenic transcription factors Runx2 and Osx, but an up-regulation of adipogenesis-related genes FABP4 and PPAR-γ. MTX also increased osteoclast density, bone marrow osteoclast formation, and mRNA expression of proinflammatory cytokines IL-1, IL-6, TNF-α, and RANKL/OPG ratio in bone. Fish oil (0.5 or 0.75 ml/100 g) or folinic acid supplementation preserved bone volume, osteoblast density, and osteogenic differentiation, and suppressed MTX-induced cytokine expression, osteoclastogenesis, and adipogenesis. Thus, fish oil at 0.5 ml/100 g or above is as effective as folinic acid in counteracting MTX-induced bone damage, conserving bone formation, suppressing resorption and marrow adiposity, suggesting its therapeutic potential in preventing bone loss during MTX chemotherapy.

Effects of Maternal Hypoxia during Pregnancy on Bone Development in Offspring: A Guinea Pig Model

Low birth weight is associated with reduced bone mass and density in adult life. However, effects of maternal hypoxia (MH) on offspring bone development are not known. Objective. The current study investigated the effects of fetal growth restriction induced by MH during the last half of gestation on bone structure and volume in the offspring of the fetus near term and the pup in adolescence. Methods. During 35-62-day gestation (term, 69d), guinea pigs were housed in room air (21% O2; control) or 12% O2 (MH). Offspring femur and tibia were collected at 62d gestation and 120d after birth. Results. MH decreased fetal birth weight but did not affect osteogenic potential pools in the fetal bone marrow. Histological analysis showed no effects of MH on tibial growth plate thickness in either fetal or postnatal offspring, although there was increased VEGF mRNA expression in the growth plate of postnatal offspring. MH did not change primary spongiosa height but lowered collagen-1 mRNA expression in postnatal offspring. There was increased mRNA expression of adipogenesis-related gene (FABP4) in bone from the MH postnatal offspring. Conclusion. MH during late gestation did not change the pool of osteogenic cells before birth or growth plate heights before and after birth. However, MH reduced expression of bone formation marker (collagen-1) and increased expression of fat formation marker (FABP4) in postnatal offspring bone.

Supplementation with fish oil and genistein, individually or in combination, protects bone against the adverse effects of methotrexate chemotherapy in rats

Cancer chemotherapy has been shown to induce long-term skeletal side effects such as osteoporosis and fractures; however, there are no preventative treatments. This study investigated the damaging effects of anti-metabolite methotrexate (MTX) subcutaneous injections (0.75 mg/kg BW) for five days and the potential protective benefits of daily oral gavage of fish oil at 0.5 mL/100 g BW (containing 375 mg of n-3 PUFA/100 g BW), genistein (2 mg/100 g BW), or their combination in young adult rats. MTX treatment alone significantly reduced primary spongiosa height and secondary spongiosa trabecular bone volume. Bone marrow stromal cells from the treated rats showed a significant reduction in osteogenic differentiation but an increase in adipogenesis ex vivo. Consistently, stromal cells had significantly higher mRNA levels of adipogenesis-related proliferator activator activated receptor-γ (PPAR-γ) and fatty acid binding protein (FABP4). MTX significantly increased the numbers of bone-resorbing osteoclasts and marrow osteoclast precursor cell pool while significantly enhancing the mRNA expression of receptor activator for nuclear factor kappa B ligand (RANKL), the RANKL/osteoprotegerin (OPG) ratio, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the bone. Supplementary treatment with fish oil and/or genistein significantly preserved trabecular bone volume and osteogenesis but suppressed MTX-induced adipogenesis and increases in osteoclast numbers and pro-osteoclastogenic cytokine expression. Thus, Fish oil and/or genistein supplementation during MTX treatment enabled not only preservation of osteogenic differentiation, osteoblast number and bone volume, but also prevention of MTX treatment-induced increases in bone marrow adiposity, osteoclastogenic cytokine expression and osteoclast formation, and thus bone loss.

Prevention of bone growth defects, increased bone resorption and marrow adiposity with folinic acid in rats receiving long-term methotrexate

The underlying pathophysiology for bone growth defects in paediatric cancer patients receiving high dose methotrexate chemotherapy remains unclear and currently there are no standardized preventative treatments for patients and survivors. Using a model in young rats, we investigated damaging effects of long-term treatment with methotrexate on growth plate and metaphyseal bone, and the potential protective effects of antidote folinic acid. This study demonstrated that chronic folinic acid supplementation can prevent methotrexate-induced chondrocyte apoptosis and preserve chondrocyte columnar arrangement and number in the growth plate. In the metaphysis, folinic acid supplementation can preserve primary spongiosa heights and secondary spongiosa trabecular volume by preventing osteoblasts from undergoing apoptosis and suppressing methotrexate-induced marrow adiposity and osteoclast formation. Systemically, plasma of folinic acid supplemented rats, in comparison to plasma from rats treated with MTX alone, contained a significantly lower level of IL-1β and suppressed osteoclast formation in vitro in normal bone marrow cells. The importance of IL-1β in supporting plasma-induced osteoclast formation was confirmed as the presence of an anti-IL-1β neutralizing antibody attenuated the ability of the plasma (from MTX-treated rats) in inducing osteoclast formation. Findings from this study suggest that folinic acid supplementation during chronic methotrexate treatment can alleviate growth plate and metaphyseal damages and therefore may be potentially useful in paediatric patients who are at risk of skeletal growth suppression due to chronic methotrexate chemotherapy.

Dietary emu oil supplementation suppresses 5-fluorouracil chemotherapy-induced inflammation, osteoclast formation, and bone loss

Cancer chemotherapy can cause osteopenia or osteoporosis, and yet the underlying mechanisms remain unclear, and currently, no preventative treatments are available. This study investigated damaging effects of 5-fluorouracil (5-FU) on histological, cellular, and molecular changes in the tibial metaphysis and potential protective benefits of emu oil (EO), which is known to possess a potent anti-inflammatory property. Female dark agouti rats were gavaged orally with EO or water (1 ml·day(-1)·rat(-1)) for 1 wk before a single ip injection of 5-FU (150 mg/kg) or saline (Sal) was given. The treatment groups were H(2)O + Sal, H(2)O + 5-FU, EO + 5-FU, and EO + Sal. Oral gavage was given throughout the whole period up to 1 day before euthanasia (days 3, 4, and 5 post-5-FU). Histological analysis showed that H(2)O + 5-FU significantly reduced heights of primary spongiosa on days 3 and 5 and trabecular bone volume of secondary spongiosa on days 3 and 4. It reduced density of osteoblasts slightly and caused an increase in the density of osteoclasts on trabecular bone surface on day 4. EO supplementation prevented reduction of osteoblasts and induction of osteoclasts and bone loss caused by 5-FU. Gene expression studies confirmed an inhibitory effect of EO on osteoclasts since it suppressed 5-FU-induced expression of proinflammatory and osteoclastogenic cytokine TNFα, osteoclast marker receptor activator of nuclear factor-κB, and osteoclast-associated receptor. Therefore, this study demonstrated that EO can counter 5-FU chemotherapy-induced inflammation in bone, preserve osteoblasts, suppress osteoclast formation, and potentially be useful in preventing 5-FU chemotherapy-induced bone loss.

Attenuated Wnt/β-catenin signalling mediates methotrexate chemotherapy-induced bone loss and marrow adiposity in rats

Cancer chemotherapy often causes significant bone loss, marrow adiposity and haematopoietic defects, yet the underlying mechanisms and recovery potential remain unclear. Wnt/β-catenin signalling is integral to the regulation of osteogenesis, adipogenesis and haematopoiesis; using a rat model, the current study investigated roles of this signalling pathway in changes to bone marrow stromal and haematopoietic cell differentiation after chemotherapy with methotrexate (MTX), a commonly used antimetabolite. MTX treatment in rats (5 daily administrations at 0.75 mg/kg) has previously been found to decrease bone volume and increase marrow fat, which was associated with increased osteoclastogenesis in haematopoietic cells and with an osteogenesis to adipogenesis switch in bone marrow stromal cells of treated rats. In the current study, on day 6 after the first MTX dose we found that accompanying these changes as well as a suppressed haematopoietic cellularity but increased granulocyte/macrophage differentiation potential, there was an increase in mRNA expression of Wnt antagonists sFRP-1 and Dkk-1 in bone, a reduction in nuclear β-catenin protein in bone marrow stromal cells, and decreased mRNA levels of β-catenin target genes lef-1, cyclin D1 and survivin, suggesting reduced activation of Wnt/β-catenin signalling in the bone during MTX-induced damage. Concurrent administration of BIO, a GSK-3β inhibitor that stabilises β-catenin, partially abrogated the MTX-induced transient changes in osteogenic/adipogenic commitment, granulocyte/macrophage lineage differentiation and osteoclast number. These findings demonstrate a potentially important role of Wnt/β-catenin signalling in MTX chemotherapy-induced cellular changes to the bone marrow microenvironment.

Perinatal maternal dietary supplementation of ω3-fatty acids transiently affects bone marrow microenvironment, osteoblast and osteoclast formation, and bone mass in male offspring

It is increasingly evident that micronutrient environment experienced before birth and in infancy is important for achieving optimal bone mass by adolescence and maintaining bone health. This study determined whether maternal supplementation with ω3-polyunsaturated fatty acids (n3FA) improved offspring bone growth and adult bone mass. Female rats were fed a diet containing 0.1% (control, n = 10) or 1% (n3FA, n = 11) docosahexanoic acid (DHA) during pregnancy and lactation. Offspring were weaned onto a control rat chow diet. Tibial growth plate and metaphysis structure, osteoblast/osteoclast density and differentiation, and gene expression were assessed in offspring at 3 wk (weaning), 6 wk (adolescent), and 3 months (adult). Maternal n3FA supplementation elevated offspring plasma n3FA levels at 3 and 6 wk. Although total growth plate heights were unaffected at any age, the resting zone thickness was increased in both male and female offspring at 3 wk. In n3FA males, but not females, bone trabecular number and thickness were increased at 3 wk but not other ages. The wk 3 n3FA males also exhibited an increased bone volume, an increased osteoblast but decreased osteoclast density, and lower expression of osteoclastogenic cytokines receptor activator of nuclear factor-κB ligand, TNF-α, and IL-6. No effects were seen at 6 wk or 3 months in either sex. Thus, perinatal n3FA supplementation is associated with increased bone formation, decreased resorption, and a higher bone mass in males, but not in females, at weaning; these effects do not persist into adolescence and adulthood and are unlikely to produce lasting improvements in bone health.

Methotrexate chemotherapy reduces osteogenesis but increases adipogenic potential in the bone marrow

Intensive use of cancer chemotherapy is increasingly linked with long-term skeletal side effects such as osteopenia, osteoporosis and fractures. However, cellular mechanisms by which chemotherapy affects bone integrity remain unclear. Methotrexate (MTX), used commonly as an anti-metabolite, is known to cause bone defects. To study the pathophysiology of MTX-induced bone loss, we examined effects on bone and marrow fat volume, population size and differentiation potential of bone marrow stromal cells (BMSC) in adult rats following chemotherapy for a short-term (five once-daily doses at 0.75 mg/kg) or a 6-week term (5 doses at 0.65 mg/kg + 9 days rest + 1.3 mg/kg twice weekly for 4 weeks). Histological analyses revealed that both acute and chronic MTX treatments caused a significant decrease in metaphyseal trabecular bone volume and an increase in marrow adipose mass. In the acute model, proliferation of BMSCs significantly decreased on days 3-9, and consistently the stromal progenitor cell population as assessed by CFU-F formation was significantly reduced on day 9. Ex vivo differentiation assays showed that while the osteogenic potential of isolated BMSCs was significantly reduced, their adipogenic capacity was markedly increased on day 9. Consistently, RT-PCR gene expression analyses showed osteogenic transcription factors Runx2 and Osterix (Osx) to be decreased but adipogenic genes PPARγ and FABP4 up-regulated on days 6 and 9 in the stromal population. These findings indicate that MTX chemotherapy reduces the bone marrow stromal progenitor cell population and induces a switch in differentiation potential towards adipogenesis at the expense of osteogenesis, resulting in osteopenia and marrow adiposity.

Deregulation of the CXCL12/CXCR4 axis in methotrexate chemotherapy-induced damage and recovery of the bone marrow microenvironment

Cancer chemotherapy disrupts the bone marrow (BM) microenvironment affecting steady-state proliferation, differentiation and maintenance of haematopoietic (HSC) and stromal stem and progenitor cells; yet the underlying mechanisms and recovery potential of chemotherapy-induced myelosuppression and bone loss remain unclear. While the CXCL12/CXCR4 chemotactic axis has been demonstrated to be critical in maintaining interactions between cells of the two lineages and progenitor cell homing to regions of need upon injury, whether it is involved in chemotherapy-induced BM damage and repair is not clear. Here, a rat model of chemotherapy treatment with the commonly used antimetabolite methotrexate (MTX) (five once-daily injections at 0.75 mg/kg/day) was used to investigate potential roles of CXCL12/CXCR4 axis in damage and recovery of the BM cell pool. Methotrexate treatment reduced marrow cellularity, which was accompanied by altered CXCL12 protein levels (increased in blood plasma but decreased in BM) and reduced CXCR4 mRNA expression in BM HSC cells. Accompanying the lower marrow CXCL12 protein levels (despite its increased mRNA expression in stromal cells) was increased gene and protein levels of metalloproteinase MMP-9 in bone and BM. Furthermore, recombinant MMP-9 was able to degrade CXCL12 in vitro. These findings suggest that MTX chemotherapy transiently alters BM cellularity and composition and that the reduced cellularity may be associated with increased MMP-9 expression and deregulated CXCL12/CXCR4 chemotactic signalling.

Prevalence, pathophysiology, screening and management of osteoporosis in gastric cancer patients

Osteoporosis in gastric cancer patients is often overlooked or even neglected despite its high prevalence in these patients. Considering that old age, malnutrition, chronic disease, chemotherapy, decreased body mass index and gastrectomy are independent risk factors for osteoporosis, it is reasonable that the prevalence of osteoporosis in gastric cancer patients would be high. Many surviving patients suffer from back pain and pathological fractures, which are related to osteoporosis. Fractures have obvious associated morbidities, negative impact on quality of life, and impose both direct and indirect costs. In the era of a >55.6% 5-year survival rate of gastric cancer and increased longevity in gastric cancer patients, it is very important to eliminate common sequelae such as osteoporosis. Fortunately, the diagnosis of osteoporosis is well established and many therapeutic agents have been shown to be effective and safe not only in postmenopausal females but also in elderly males. Recently, effective treatments of gastric cancer patients with osteoporosis using bisphosphonates, which are commonly used in postmenopausal woman, were reported.

Interaction of dietary zinc and intracellular binding protein metallothionein in postnatal bone growth

Zinc and its binding protein, metallothionein (MT), are important in regulating growth and development, and yet it is unclear how dietary Zn and MT interact in regulating bone growth. Here, 3.5-week female MT-I&II knockout (MT(-/-)) and wild type (MT(+/+)) mice were fed diets containing 2.5 (limiting, Zn-L), 15 or 50 mg Zn/kg (Zn adequate) for 5 or 9 weeks, and effects were analysed on structure and function of growth plate and metaphysis, two structures important for bone growth. Zn limitation did not affect bone growth in MT(+/+) mice. However, MT(-/-) mice, having lower Zn concentrations in plasma and long bone, showed growth retardation as demonstrated by lower body length gain, shorter and smaller tibia/femur, lower chondrocyte proliferation, reduced metaphysis heights, but increased osteoclast densities on trabecular bone, particularly in mice fed Zn-L diet. Interestingly, mRNA expression of MT-I&II was induced in the growth plate of MT(+/+) mice fed the Zn-L diet possibly compensating for Zn limitation. Growth plate MT-III expression increased in MT(-/-) mice fed the adequate Zn diet, whereas metaphyseal MT-III was significantly upregulated in MT(-/-) mice fed Zn-L diet, possibly as a compensatory mechanism or exacerbating effects of Zn limitation. Consistent with the increased osteoclast numbers, a higher ratio of RANKL/OPG gene expression was found in bone of mutant mice fed lower Zn diets. These results indicate that interaction between dietary Zn and endogenous MT is important for maximal bone growth, and MT is particularly important in the regulation of Zn pool for bone growth during moderate Zn limitation.

Damaging effects of chronic low-dose methotrexate usage on primary bone formation in young rats and potential protective effects of folinic acid supplementary treatment

Methotrexate (MTX) is a most commonly used anti-metabolite in cancer treatment and as an anti-rheumatic drug. While MTX chemotherapy at a high dose is known to cause bone growth defects in growing bones, effects of its chronic use at a low dose on growing skeleton remain less clear. Here, we examined effects on bone growth of long-term MTX chemotherapy at a low dose in young rats, and potential protective effects of supplementary treatment with antidote folinic acid (given ip at 1 mg/kg 6 h after MTX). After two cycles of 5 once-daily MTX injections (at 0.75 mg/kg, 5 days on/9 days off/5 days on), histological analysis showed that MTX at this dose caused significant reduction in heights of growth plate and primary spongiosa bone on day 22 compared to controls (P<0.05). In contrast, a similar dosing regimen but at a lower dose (0.4 mg/kg) caused only slight or no reduction in heights of both regions. However, after the induction phase at this 0.4 mg/kg dosing, continued use of MTX at a low dose (once weekly at 0.2 mg/kg) caused a reduction in primary spongiosa height and bone volume on weeks 9 and 14, which was associated with an increased osteoclast formation and their bone surface density as well as a decreased osteoblast bone surface density in the primary spongiosa. Folinic acid supplementation was shown able to prevent the MTX effects in the primary spongiosa. These results suggest that acute use of MTX can damage growth plate and primary bone at a high dose, but not at a low dose. However, long-term use of MTX at a low dose can reduce primary bone formation probably due to decreased osteoblastic function but increased osteoclastic formation and function, and supplementary treatment with folinic acid may be potentially useful in protecting bone growth during long-term low-dose MTX chemotherapy.

Short-term changes in bone and mineral metabolism following gastrectomy in gastric cancer patients

Changes in bone and mineral metabolism that occur after gastrectomy have long been recognized. Gastrectomy has been identified as a risk factor for decreased bone mass and the increased fracture incidence. Previous investigations concerning postgastrectomy bone disease have been observational studies. No prospective studies have been reported that quantify the amount of bone loss after gastrectomy within the same patients. This study investigated 46 patients undergoing gastrectomy for gastric adenocarcinoma and analyzed 36 patients (58.1+/-10.8 years, 24 men and 12 women) who had dual energy X-ray absorptiometry (DXA) performed before and 1 year after gastrectomy. Systemic adjuvant chemotherapy was administered to 14 patients. Blood was sampled from all patients to determine serum calcium, phosphorous, and bone turnover marker levels before gastrectomy and at 1, 3, 6 and 12 months after surgery and for serum parathyroid hormone (PTH) and 25-hydroxyvitamin D levels before and 12 months after surgery. The mean bone loss in the lumbar spine, total hip, femoral neck, and trochanter, which was calculated as the percentage change from the baseline to the level measured at 12 months, was 5.7% (P<0.01), 5.4% (P<0.01), 6.6% (P<0.01) and 8.7% (P<0.01), respectively. Bone loss was generally greater in the group receiving chemotherapy. The serum calcium and phosphorous levels were not changed significantly and remained within the normal range throughout the observation period. After gastrectomy, the level of ICTP increased and reached a peak at 1 and 3 months, and progressively declined to baseline by 12 months. The osteocalcin levels were not coupled to an increase before 6 months. The level of 25-hydroxyvitamin D at 12 months postgastrectomy was not significantly changed compared to the baseline, however, the PTH levels increased by a mean of 63.6% at 12 months compared to the baseline (P<0.01). Significant correlations were found between the percent change in the BMD at the lumbar spine and total hip and the percentage change for the PTH level from their baselines to 12 months. The changes in the BMD at total hip, femoral neck, and trochanter also correlated to the change in body weight at 12 months. The data obtained by this study provides evidence that profound bone loss occurs in the setting of a bone remodeling imbalance during the early postgastrectomy period and allows the speculation that the gastrectomy related bone loss may be partially due to an overproduction of PTH.

Cellular mechanisms for methotrexate chemotherapy-induced bone growth defects

Methotrexate (MTX) is a commonly used anti-metabolite in childhood oncology and is known to cause bone growth arrest and osteoporosis; yet the underlying mechanisms for MTX-induced bone growth defects remain largely unclear. This study characterized damaging effects in young rats of acute chemotherapy with 5 once-daily doses of MTX (0.75 mg/kg) on the cellular activities in the growth plate in producing calcified cartilage and trabecular bone and on activities of osteoblastic cells in the metaphysis. MTX treatment significantly induced chondrocyte apoptosis. MTX also suppressed chondrocyte proliferation and reduced collagen-II mRNA expression and total thickness of the growth plate, with the damage being most obvious on day 9 after the first injection, and with the growth plate histological structure returning normal on day 14. In the adjacent metaphyseal bone, mirroring the decrease in the width of the growth plate, production of primary spongiosa bone was markedly reduced and bone volume of the secondary spongiosa was decreased. Furthermore, MTX treatment significantly induced osteocyte apoptosis in the primary spongiosa and reduced proliferation of osteoblasts and preosteoblasts particularly in the secondary spongiosa. These observations suggest that methotrexate chemotherapy may cause bone growth defects by arresting cellular activities in the growth plate in producing calcified cartilage and primary trabecular bone and by decreasing pools of metaphyseal osteoblastic cells. However, this short-term MTX treatment only caused transit suppressions on growth plate cartilage and trabecular bone, as most cellular and histological parameters had recovered by day 14 or 21.

Folinic acid attenuates methotrexate chemotherapy-induced damages on bone growth mechanisms and pools of bone marrow stromal cells

Chemotherapy often induces bone growth defects in pediatric cancer patients; yet the underlying cellular mechanisms remain unclear and currently no preventative treatments are available. Using an acute chemotherapy model in young rats with the commonly used antimetabolite methotrexate (MTX), this study investigated damaging effects of five once-daily MTX injections and potential protective effects of supplementary treatment with antidote folinic acid (FA) on cellular activities in the tibial growth plate, metaphysis, and bone marrow. MTX suppressed proliferation and induced apoptosis of chondrocytes, and reduced collagen-II expression and growth plate thickness. It reduced production of primary spongiosa bone, volume of secondary spongiosa bone, and proliferation of metaphyseal osteoblasts, preosteoblasts and bone marrow stromal cells, with the cellular activities being most severely damaged on day 9 and returning to or towards near normal levels by day 14. On the other hand, proliferation of marrow pericytes was increased early after MTX treatment and during repair. FA supplementation significantly suppressed chondrocyte apoptosis, preserved chondrocyte proliferation and expression of collagen-II, and attenuated damaging effects on production of calcified cartilage and primary bone. The supplementation also significantly reduced MTX effects on proliferation of metaphyseal osteoblastic cells and of bone marrow stromal cells, and enhanced pericyte proliferation. These observations suggest that FA supplementation effectively attenuates MTX damage on cellular activities in producing calcified cartilage and primary trabecular bone and on pools of osteoblastic cells and marrow stromal cells, and that it enhances proliferation of mesenchymal progenitor cells during bone/bone marrow recovery.