Effects of fine particulate matter on bone marrow-conserved hematopoietic and mesenchymal stem cells: a systematic review.

The harmful effects of fine particulate matter ≤2.5 µm in size (PM2.5) on human health have received considerable attention. However, while the impact of PM2.5 on the respiratory and cardiovascular systems has been well studied, less is known about the effects on stem cells in the bone marrow (BM). With an emphasis on the invasive characteristics of PM2.5, this review examines the current knowledge of the health effects of PM2.5 exposure on BM-residing stem cells. Recent studies have shown that PM2.5 enters the circulation and then travels to distant organs, including the BM, to induce oxidative stress, systemic inflammation and epigenetic changes, resulting in the reduction of BM-residing stem cell survival and function. Understanding the broader health effects of air pollution thus requires an understanding of the invasive characteristics of PM2.5 and its direct influence on stem cells in the BM. As noted in this review, further studies are needed to elucidate the underlying processes by which PM2.5 disturbs the BM microenvironment and inhibits stem cell functionality. Strategies to prevent or ameliorate the negative effects of PM2.5 exposure on BM-residing stem cells and to maintain the regenerative capacity of those cells must also be investigated. By focusing on the complex relationship between PM2.5 and BM-resident stem cells, this review highlights the importance of specific measures directed at safeguarding human health in the face of rising air pollution.

Osteoblastic Wls Ablation Protects Mice from Total Body Irradiation-Induced Impairments in Hematopoiesis and Bone Marrow Microenvironment.

Ionizing irradiation (IR) causes bone marrow (BM) injury, with senescence and impaired self-renewal of hematopoietic stem cells (HSCs), and inhibiting Wnt signaling could enhance hematopoietic regeneration and survival against IR stress. However, the underlying mechanisms by which a Wnt signaling blockade modulates IR-mediated damage of BM HSCs and mesenchymal stem cells (MSCs) are not yet completely understood. We investigated the effects of osteoblastic Wntless (Wls) depletion on total body irradiation (TBI, 5 Gy)-induced impairments in hematopoietic development, MSC function, and the BM microenvironment using conditional Wls knockout mutant mice (Col-Cre;Wlsfl/fl) and their littermate controls (Wlsfl/fl). Osteoblastic Wls ablation itself did not dysregulate BM frequency or hematopoietic development at a young age. Exposure to TBI at 4 weeks of age induced severe oxidative stress and senescence in the BM HSCs of Wlsfl/fl mice but not in those of the Col-Cre;Wlsfl/fl mice. TBI-exposed Wlsfl/fl mice exhibited greater impairments in hematopoietic development, colony formation, and long-term repopulation than TBI-exposed Col-Cre;Wlsfl/fl mice. Transplantation with BM HSCs or whole BM cells derived from the mutant, but not Wlsfl/fl mice, protected against HSC senescence and hematopoietic skewing toward myeloid cells and enhanced survival in recipients of lethal TBI (10 Gy). Unlike the Wlsfl/fl mice, the Col-Cre;Wlsfl/fl mice also showed radioprotection against TBI-mediated MSC senescence, bone mass loss, and delayed body growth. Our results indicate that osteoblastic Wls ablation renders BM-conserved stem cells resistant to TBI-mediated oxidative injuries. Overall, our findings show that inhibiting osteoblastic Wnt signaling promotes hematopoietic radioprotection and regeneration.

Exposure of newborns to atmospherically relevant artificial particulate matter induces hematopoietic stem cell senescence.

Research on the negative impacts of PM2.5 have been focused on lung, brain, immune, and metabolism-related diseases. However, little is known about the mechanism underlying the effects of PM2.5 on the modulation of hematopoietic stem cell (HSC) fate. Maturation of the hematopoietic system and differentiation of hematopoietic stem progenitor cells (HSPCs) occurs soon after birth when infants are susceptible to external stresses. We investigated how exposure to atmospherically relevant artificial particulate matter of diameter < 2.5 µm (termed, PM2.5) affects HSPCs in newborns. The lungs of newborn mice exposed to PM2.5 exhibited higher levels of oxidative stress and inflammasome activation, which continued during aging. PM2.5 also stimulated oxidative stress and inflammasome activation in bone marrow (BM). PM2.5-exposed infant mice at 12 months but not at 6 months displayed progressive senescence of HSCs accompanied by preferential impairment of the BM microenvironment with age-related phenotypes, as evidenced by colony-forming assay and serial transplantation and animal survival experiments. Further, PM2.5-exposed middle-aged mice did not exhibit radioprotective potential. Collectively, exposure of newborns to PM2.5 causes progressive senescence of HSCs. These findings revealed a novel mechanism by which PM2.5 affects the fate of HSCs, highlighting the crucial role of early life exposure to air pollution in determining human health outcomes.

Prion infection modulates hematopoietic stem/progenitor cell fate through cell-autonomous and non-autonomous mechanisms.

Studies of PrPC-derived prion disease generally focus on neurodegeneration. However, little is known regarding the modulation of hematopoietic stem progenitor cells (HSPCs) that express PrPC in prion infection. Among bone marrow (BM) hematopoietic cells, hematopoietic stem cells (HSCs) strongly express PrPC. A bioassay revealed the presence of misfolded prion protein (PrPSc) in BM cells derived from prion-infected mice; these BM cells demonstrated reproducible prion infectivity. At 5 months after infection with ME7, mice exhibited a significant decrease in the number of HSPCs. This decrease was mainly driven by increased apoptotic cell death, rather than cell cycle progression and senescence, in PrPC-positive but not PrPC-negative HSPC populations through a cell-autonomous mechanism. Notably, both PrPC-positive and PrPC-negative HSCs underwent cellular senescence, as indicated by high levels of senescence-associated factors and deficits in repopulation and self-renewal capacities at 7 months after infection. Senescence of HSCs occurred in the ME7-impaired BM microenvironment with aging phenotypes through non-cell autonomous mechanisms. These data provide novel evidence that prion infection differentially modulates HSC fate through both cell-autonomous and non-autonomous mechanisms.

Local and Systemic Overexpression of COMP-Ang1 Induces Ang1/Tie2-Related Thrombocytopenia and SDF-1/CXCR4-Dependent Anemia.

While supplemental angiopoietin-1 (Ang1) improves hematopoiesis, excessive Ang1 induces bone marrow (BM) impairment, hematopoietic stem cell (HSC) senescence, and erythropoietic defect. Here, we examined how excessive Ang1 disturbs hematopoiesis and explored whether hematopoietic defects were related to its level using K14-Cre;c-Ang1 and Col2.3-Cre;c-Ang1 transgenic mice that systemically and locally overexpress cartilage oligomeric matrix protein-Ang1, respectively. We also investigated the impacts of Tie2 inhibitor and AMD3100 on hematopoietic development. Transgenic mice exhibited excessive angiogenic phenotypes, but K14-Cre;c-Ang1 mice showed more severe defects in growth and life span with higher presence of Ang1 compared with Col2.3-Cre;c-Ang1 mice. Dissimilar to K14-Cre;c-Ang1 mice, Col2.3-Cre;c-Ang1 mice did not show impaired BM retention or senescence of HSCs, erythropoietic defect, or disruption of the stromal cell-derived factor 1 (SDF-1)/CXCR4 axis. However, these mice exhibited a defect in platelet production depending on the expression of Tie2 and globin transcription factor 1 (GATA-1), but not GATA-2, in megakaryocyte progenitor (MP) cells. Treatment with Tie2 inhibitor recovered GATA-1 expression in MP cells and platelet production without changes in circulating RBC in transgenic mice. Consecutive AMD3100 administration not only induced irrecoverable senescence of HSCs but also suppressed formation of RBC, but not platelets, via correlated decreases in number of erythroblasts and their GATA-1 expression in B6 mice. Our results indicate that genetic overexpression of Ang1 impairs hematopoietic development depending on its level, in which megakaryopoiesis is preferentially impaired via activation of Ang1/Tie2 signaling, whereas erythropoietic defect is orchestrated by HSC senescence, inflammation, and disruption of the SDF-1/CXCR4 axis.

Astaxanthin Protects against Hyperglycemia-Induced Oxidative and Inflammatory Damage to Bone Marrow and to Bone Marrow-Retained Stem Cells and Restores Normal Hematopoiesis in Streptozotocin-Induced Diabetic Mice.

Hyperglycemia has various adverse health effects, some of which are due to chronic oxidative and inflammatory impairment of bone marrow (BM), hematopoietic stem cells (HSCs), and mesenchymal stem cells (MSCs). Astaxanthin (ASTX) has been shown to ameliorate hyperglycemia-associated systemic complications and acute mortality, and this effect is partially associated with restoration of normal hematopoiesis. Here, the effects of ASTX on diabetes-induced complications in BM and BM stem cells were investigated, and the underlying molecular mechanisms were elucidated. Ten-week-old C57BL/6 mice received a single intraperitoneal injection of streptozotocin (STZ; 150 mg/kg) in combination with oral gavage of ASTX (12.5 mg/kg) for 30 or 60 consecutive days. Supplemental ASTX ameliorated acute mortality and restored the STZ-impaired bone mass accrual and BM microenvironment in STZ-injected mice. Oral gavage of ASTX suppressed osteoclast formation in the BM of STZ-injected mice. Specifically, supplementation with ASTX inhibited oxidative stress and senescence induction of BM HSCs and MSCs and ameliorated hematopoietic disorders in STZ-injected mice. These effects of ASTX were associated with BM restoration of angiopoietin 1, stromal cell-derived factor 1, ß-catenin, and Nrf2. Long-term ASTX gavage also recovered the STZ-induced dysfunction in migration, colony formation, and mineralization of BM-derived stromal cells. Further, a direct addition of ASTX exhibited direct and dose-dependent inhibition of osteoclastic activation without cytotoxic effects. Collectively, these results indicate that ASTX protects against diabetes-induced damage in the BM microenvironment in BM, HSCs, and MSCs and restores normal hematopoiesis and bone accrual in STZ-injected mice.

Astaxanthin Inhibits Diabetes-Triggered Periodontal Destruction, Ameliorates Oxidative Complications in STZ-Injected Mice, and Recovers Nrf2-Dependent Antioxidant System.

Numerous studies highlight that astaxanthin (ASTX) ameliorates hyperglycemic condition and hyperglycemia-associated chronic complications. While periodontitis and periodontic tissue degradation are also triggered under chronic hyperglycemia, the roles of ASTX on diabetes-associated periodontal destruction and the related mechanisms therein are not yet fully understood. Here, we explored the impacts of supplemental ASTX on periodontal destruction and systemic complications in type I diabetic mice. To induce diabetes, C57BL/6 mice received a single intraperitoneal injection of streptozotocin (STZ; 150 mg/kg), and the hyperglycemic mice were orally administered with ASTX (12.5 mg/kg) (STZ+ASTX group) or vehicle only (STZ group) daily for 60 days. Supplemental ASTX did not improve hyperglycemic condition, but ameliorated excessive water and feed consumptions and lethality in STZ-induced diabetic mice. Compared with the non-diabetic and STZ+ASTX groups, the STZ group exhibited severe periodontal destruction. Oral gavage with ASTX inhibited osteoclastic formation and the expression of receptor activator of nuclear factor (NF)-κB ligand, 8-OHdG, γ-H2AX, cyclooxygenase 2, and interleukin-1ß in the periodontium of STZ-injected mice. Supplemental ASTX not only increased the levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and osteogenic transcription factors in the periodontium, but also recovered circulating lymphocytes and endogenous antioxidant enzyme activity in the blood of STZ-injected mice. Furthermore, the addition of ASTX blocked advanced glycation end products-induced oxidative stress and growth inhibition in human-derived periodontal ligament cells by upregulating the Nrf2 pathway. Together, our results suggest that ASTX does not directly improve hyperglycemia, but ameliorates hyperglycemia-triggered periodontal destruction and oxidative systemic complications in type I diabetes.

Supplemental Ferulic Acid Inhibits Total Body Irradiation-Mediated Bone Marrow Damage, Bone Mass Loss, Stem Cell Senescence, and Hematopoietic Defect in Mice by Enhancing Antioxidant Defense Systems.

While total body irradiation (TBI) is an everlasting curative therapy, the irradiation can cause long-term bone marrow (BM) injuries, along with senescence of hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) via reactive oxygen species (ROS)-induced oxidative damages. Thus, ameliorating or preventing ROS accumulation and oxidative stress is necessary for TBI-requiring clinical treatments. Here, we explored whether administration of ferulic acid, a dietary antioxidant, protects against TBI-mediated systemic damages, and examined the possible mechanisms therein. Sublethal TBI (5 Gy) decreased body growth, lifespan, and production of circulating blood cells in mice, together with ROS accumulation, and senescence induction of BM-conserved HSCs and MSCs. TBI also impaired BM microenvironment and bone mass accrual, which was accompanied by downregulated osteogenesis and by osteoclastogenic and adipogenic activation in BM. Long-term intraperitoneal injection of ferulic acid (50 mg/kg body weight, once per day for 37 consecutive days) protected mice from TBI-mediated mortality, stem cell senescence, and bone mass loss by restoring TBI-stimulated disorders in osteogenic, osteoclastic, and adipogenic activation in BM. In vitro experiments using BM stromal cells supported radioprotective effects of ferulic acid on TBI-mediated defects in proliferation and osteogenic differentiation. Overall, treatment with ferulic acid prevented TBI-mediated liver damage and enhanced endogenous antioxidant defense systems in the liver and BM. Collectively, these results support an efficient protection of TBI-mediated systemic defects by supplemental ferulic acid, indicating its clinical usefulness for TBI-required patients.

Overexpression of COMP-Angiopoietin-1 in K14-Expressing Cells Impairs Hematopoiesis and Disturbs Erythrocyte Maturation.

Numerous studies highlight the potential benefits potentials of supplemental cartilage oligomeric matrix protein-angiopoietin-1 (COMP-Ang1) through improved angiogenic effects. However, our recent findings show that excessive overexpression of COMP-Ang1 induces an impaired bone marrow (BM) microenvironment and senescence of hematopoietic stem cells (HSCs). Here, we investigated the underlying mechanisms of how excessive COMP-Ang1 affects the function of BM-conserved stem cells and hematopoiesis using K14-Cre;inducible-COMP-Ang1-transgenic mice. Excessive COMP-Ang1 induced peripheral egression and senescence of BM HSCs and mesenchymal stem cells (MSCs). Excessive COMP-Ang1 also caused abnormal hematopoiesis along with skewed differentiation of HSCs toward myeloid lineage rather than lymphoid lineage. Especially, excessive COMP-Ang1 disturbed late-stage erythroblast maturation, followed by decreased expression of stromal cell-derived factor 1 (SDF-1) and globin transcription factor 1 (GATA-1) and increased levels of superoxide anion and p-p38 kinase. However, transplantation with the mutant-derived BM cells or treatment with rhCOMP-Ang1 protein did not alter the frequency or GATA-1 expression of erythroblasts in recipient mice or in cultured BM cells. Together, our findings suggest that excessive COMP-Ang1 impairs the functions of BM HSCs and MSCs and hematopoietic processes, eventually leading to abnormal erythropoiesis via imbalanced SDF-1/CXCR4 axis and GATA-1 expression rather than Ang1/Tie2 signaling axis alterations.

The Long-lasting Radioprotective Effect of Caffeic Acid in Mice Exposed to Total Body Irradiation by Modulating Reactive Oxygen Species Generation and Hematopoietic Stem Cell Senescence-Accompanied Long-term Residual Bone Marrow Injury.

Total body irradiation (TBI) serves as an effectively curative therapy for cancer patients and adversely causes long-term residual bone marrow (BM) injury with premature senescence of hematopoietic stem cells (HSCs), which is mediated by increased production of reactive oxygen species (ROS). In the present study, we investigated how the exposure time of TBI in a mouse model affects HSCs and whether the treatment of caffeic acid (CA), a known dietary phenolic antioxidant, has a radioprotective effect. Single (S)-TBI at a sublethal dose (5 Gy) caused relatively higher induction of mitochondrial ROS and senescence-related factors in HSCs than those in hematopoietic progenitor cells (HPCs) and Lineage-Sca-1+c-Kit+ (LSK) cells, as well as reduced clonogenic formation and donor cell-derived reconstituting capacity. Repetitive double (D)-TBI (two months after the S-TBI at a dose of 5Gy) further weakened HSPC function via mitochondrial ROS accumulation and senescence-associated ß-galactosidase (SA-ß-gal) activity. Oral administration of CA (20 mg/kg) five times before and once immediately after TBI ameliorated ROS generation and TBI-induced HSC senescence and its radioprotective effect was long lasting in S-TBI mice but not in D-TBI mice. Further, supplementation of CA also induced apoptotic cell death of colon cancer cells. Collectively, these findings indicate that CA has a dual effect, ameliorating HSC senescence-accompanied long-term BM injury in S-TBI mice and stimulating apoptotic cell death of colon cancer cells.

Recombinant human IGF-1 produced by transgenic plant cell suspension culture enhances new bone formation in calvarial defects.

Transgenic plant cell suspension culture systems have been utilized extensively as convenient and efficient expression systems for the production of recombinant human growth factors. We produced insulin-like growth factor-1 using a plant suspension culture system (p-IGF-1) and explored its effect on new bone formation in calvarial defects. We also compared the bone regenerating potential of p-IGF-1 with commercial IGF-1 derived from Escherichia coli (e-IGF-1). Male C57BL/6 mice underwent calvarial defect surgery, and the defects were loaded with absorbable collagen sponge (ACS) only (ACS group) or ACS impregnated with 13µg of p-IGF-1 (p-IGF-1 group) or e-IGF-1 (e-IGF-1 group). The sham group did not receive any treatment with ACS or IGFs after surgery. Live µCT and histological analyses showed critical-sized bone defects in the sham group, whereas greater bone formation was observed in the p-IGF-1 and e-IGF-1 groups than the ACS group both 5 and 10weeks after surgery. Bone mineral density, bone volume, and bone surface values were also higher in the IGF groups than in the ACS group. Local delivery of p-IGF-1 or e-IGF-1 more greatly enhanced the expression of osteoblast-specific markers, but inhibited osteoclast formation, in newly formed bone compared with ACS control group. Specifically, p-IGF-1 treatment induced higher expression of alkaline phosphatase, osteocalcin, and osteopontin in the defect site than did e-IGF-1. Furthermore, treatment with p-IGF-1, but not e-IGF-1, increased mineralization of MC3T3-E1 cells, with the attendant upregulation of osteogenic marker genes. Collectively, our findings suggest the potential of p-IGF-1 in promoting the processes required for bone regeneration.

Anti-inflammatory, anti-osteoclastic, and antioxidant activities of genistein protect against alveolar bone loss and periodontal tissue degradation in a mouse model of periodontitis.

Genistein, a dietary polyphenol primarily found in soy products, has beneficial effects on bone. However, the effect of genistein on inflammatory periodontal destruction has not been investigated in detail. We explored whether genistein protects against lipopolysaccharide (LPS)/ligature-induced periodontitis in mice. We also examined the effect of genistein on LPS-stimulated inflammatory and oxidative stress using RAW 264.7 macrophages and human gingival fibroblasts (hGFs). The results from µCT and histological analyses revealed that intraperitoneal injection of genistein (20 mg/kg body weight) daily for three weeks inhibited LPS-mediated alveolar bone loss and periodontal tissue degradation. The administration of genistein also inhibited osteoclast formation and the expression of inflammation-related molecules in the inflamed region of mice with periodontitis. Treatment with 30-70 µM genistein significantly prevented osteoclast differentiation in receptor activator of nuclear factor κB ligand- or LPS-stimulated macrophages by suppressing the expression of osteoclast-specific molecules. The addition of genistein led to a dose-dependent inhibition of the expression of inflammation-related molecules both in LPS-stimulated macrophages and hGFs. In addition, genistein at 50 µM protected hGFs from LPS-mediated stresses such as mitochondrial impairment and cellular ROS accumulation. However, such protection was significantly diminished by combined treatment with 25 nM bafilomycin A1, a chemical autophagy inhibitor. Collectively, our results indicate that genistein protects against inflammatory periodontal damage by regulating autophagy induction and inhibiting osteoclast activation, the production of inflammation mediators, and mitochondrial oxidative damage. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2510-2521, 2017.

Local delivery of recombinant human FGF7 enhances bone formation in rat mandible defects.

Fibroblast growth factor 7 (FGF7) plays an important role in regulating the proliferation, migration, and differentiation of cells. However, the role of FGF7 in bone formation is not yet fully understood. We examined the effect of FGF7 on bone formation using a rat model of mandible defects. Rats underwent mandible defect surgery and then either scaffold treatment alone (control group) or FGF7-impregnated scaffold treatment (FGF7 group). Micro-CT and histological analyses revealed that the FGF7 group exhibited greater bone formation than did the control group 10 weeks after surgery. With the exception of total porosity (%), all bone parameters had higher values in the FGF7 group than in the control group at each follow-up after surgery. The FGF7 group showed greater expression of osteogenic markers, such as runt-related transcription factor 2, osterix, osteocalcin, bone morphogenetic protein 2, osteopontin, and type I collagen in newly formed bone than did the control group. The delivery of FGF7 also increased the messenger RNA expression of stromal-cell-derived factor 1 (SDF-1) and CXCR4 in newly formed bone in the FGF7 group compared with the control group. Further, addition of exogenous FGF7 induced migration of rat bone marrow stromal cells and increased the expression of SDF-1 and CXCR4 in the cells. Furthermore, the addition of FGF7 augmented mineralization in the cells with increased expression of osteogenic markers, and this augmentation was significantly suppressed by an inhibitor specific for c-Jun N-terminal kinase (SP600125) or extracellular-signal-regulated kinase (PD98059). Collectively, these results suggest that local delivery of FGF7 increases bone formation in a mandible defect with enhanced osteogenesis and chemoattraction.

Brief Report: Consecutive Alendronate Administration-Mediated Inhibition of Osteoclasts Improves Long-Term Engraftment Potential and Stress Resistance of HSCs.

Osteoclasts form a bone marrow (BM) cavity serving as a hematopoietic niche for the maintenance of hematopoietic stem cells (HSCs). However, the role of osteoclasts in the BM has been controversially reported and remains to be further understood. In the present study, we investigated how osteoclasts affect the modulation of hematopoietic stem/progenitor cells in the BM by administering bisphosphate alendronate (ALN) to B6 mice for 21 consecutive days to inhibit osteoclast activity. ALN treatment caused a reduction in the number of tartrate-resistant acid phosphate (TRAP)-positive osteoclast cells and an increase in bone mineral density, particularly in the trabecular zone, but not in the cortical zone of the BM. Osteoclast inhibition caused by ALN treatment decreased mitochondrial reactive oxygen species (ROS) generation and SA-ß-gal activity of CD150+ CD48- Lineage-Sca-1+ c-Kit+ (LSK) cells, eventually leading to an improvement in the engraftment potential and self-renewal activity of HSCs. Moreover, ALN-treated mice exhibited an enhanced resistance of HSCs in response to the genotoxic stress of 5-fluorouracil, as determined by mitochondrial ROS generation, SA-ß-gal activity, and p16INK4a expression in subsets of LSK and CD150+ CD48- LSK cells as well as competitive assay. Collectively, our findings indicate that inhibition of osteoclast activity improves the long-term engraftment potential and stress resistance of HSCs. Stem Cells 2016;34:2601-2607.

Intestinal anti-inflammatory activity of the seeds of Raphanus sativus L. in experimental ulcerative colitis models.

ETHNOPHARMACOLOGICAL RELEVANCE: Water extract of Raphanus sativus L. (RSL) seeds was traditionally used to treat digestive inflammatory complaints in Korean culture. RSL seeds exerted antioxidant, anti-inflammatory, and anti-septic functions, suggesting their pharmacological potential for the treatment of inflammatory pathologies associated with oxidative stress such as inflammatory bowel disease. AIM OF THIS STUDY: We evaluated the intestinal anti-inflammatory effects of RSL seed water extract (RWE) in experimental rat models of trinitrobenzenesulphonic acid (TNBS)- or dextran sodium sulfate (DSS)-induced colitis. MATERIALS AND METHODS: RWE was characterized by determining the content of sinapic acid as a reference material and then assayed in the DSS and TNBS models of rat colitis. Male Sprague-Dawley rats were divided into 10 groups (n=7/group): non-colitic control, DSS or TNBS control, DSS colitis groups treated with RWE (100mg/kg) or mesalazine (25mg/kg), and TNBS colitis groups treated with various doses (10, 40, 70, and 100mg/kg) of RWE or mesalazine (25mg/kg). RWE or mesalazine treatment started the same day of colitis induction and rats were sacrificed 24h after the last treatment followed by histological and biochemical analyses. RESULTS: Oral administration with RWE suppressed intestinal inflammatory damages in both DSS- and TNBS-induced colitic rats. The treatment with 100mg/kg RWE recovered intestinal damages caused by TNBS or DSS to levels similar to that of mesalazine, decreasing the activity of myeloperoxidase activity and the secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß. RWE treatment inhibited malondialdehyde production and glutathione reduction in colon of colitis rats. The administration of RWE at dose of 100mg/kg also suppressed the TNBS- or DSS-stimulated expression of TNF-α, IL-1ß, monocyte chemotactic protein-1, inducible nitric oxide, and intercellular adhesion molecule-1. Furthermore, RWE inhibited p38 kinase and DNA-nuclear factor-κB binding activities, both of which were stimulated in the colitic rats. CONCLUSIONS: The current findings show that RWE ameliorates intestinal oxidative and inflammatory damages in DSS and TNBS models of rat colitis, suggesting its beneficial use for the treatment of intestinal inflammatory disorders.

Resveratrol prevents alveolar bone loss in an experimental rat model of periodontitis.

Resveratrol is an antioxidant and anti-inflammatory polyphenol. Periodontitis is induced by oral pathogens, where a systemic inflammatory response accompanied by oxidative stress is the major event initiating disease. We investigated how resveratrol modulates cellular responses and the mechanisms related to this modulation in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (hGFs). We also explored whether resveratrol protects rats against alveolar bone loss in an experimental periodontitis model. Periodontitis was induced around the first upper molar of the rats by applying ligature infused with LPS. Stimulating hGFs with 5µg/ml LPS augmented the expression of cyclooxygenase-2, matrix metalloproteinase (MMP)-2, MMP-9, and Toll-like receptor-4. LPS treatment also stimulated the production of reactive oxygen species (ROS) and the phosphorylation of several protein kinases in the cells. However, the expression of heme oxygenase-1 (HO-1) and nuclear factor-E2 related factor 2 (Nrf2) was inhibited by the addition of LPS. Resveratrol treatment almost completely inhibited all of these changes in LPS-stimulated cells. Specifically, resveratrol alone augmented HO-1 induction via Nrf2-mediated signaling. Histological and micro-CT analyses revealed that administration of resveratrol (5mg/kg body weight) improved ligature/LPS-mediated alveolar bone loss in rats. Resveratrol also attenuated the production of inflammation-related proteins, the formation of osteoclasts, and the production of circulating ROS in periodontitis rats. Furthermore, resveratrol suppressed LPS-mediated decreases in HO-1 and Nrf2 levels in the inflamed periodontal tissues. Collectively, our findings suggest that resveratrol protects rats from periodontitic tissue damage by inhibiting inflammatory responses and by stimulating antioxidant defense systems. STATEMENT OF SIGNIFICANCE: The aims of this study were to investigate how resveratrol modulates cellular responses and the mechanisms related to this modulation in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (hGFs) and protects rats against alveolar bone disruption in an experimental periodontitis model. Our findings suggest that resveratrol protects rats from periodontitic tissue damage by inhibiting inflammatory responses and by stimulating antioxidant defense systems. On the basis of our experiment studies, we proposed that resveratrol could be used as novel bioactive materials or therapeutic drug for the treatment of periodontitis or other inflammatory bone diseases like osteoporosis, arthritis etc. Furthermore, it could be also used for the modification or coating of implant materials as an antiinflammatory molecules which will help to accelerate bone formation. There are a few of reports suggesting antioxidant and anti-inflammatory potentials of resveratrol. However, our results highlight the cellular mechanisms by which resveratrol inhibits LPS-mediated cellular damages using human-originated gingival fibroblasts and also support the potential of resveratrol to suppress periodontitis-mediated tissue damages. We believe that the present findings might improve a clinical approach of using of resveratrol on human, although further detailed experiments will be needed.

Local delivery of COMP-angiopoietin 1 accelerates new bone formation in rat calvarial defects.

Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent in bone reconstruction. However, the potential of COMP-Ang1 to regenerate impaired bone and induce new bone formation has not been completely explored. In this study, male Sprague-Dawley rats underwent calvarial defect surgery and divided into two groups: scaffold treatment alone (control group) and COMP-Ang1-impregnated scaffold (COMP-Ang1 group). According to live micro-CT and histological analyses, the COMP-Ang1 group showed greater new bone formation and maturation than did the control both four and eight weeks after surgery. The values of bone volume, bone mineral density, and bone surface were also higher in the COMP-Ang1 group than in the control at the same weeks after surgery. In addition, the delivery of COMP-Ang1 facilitated significantly the expression of osteoblast-specific markers such as runt-related transcription factor 2 (p < 0.001), osterix (p < 0.001), bone morphogenetic protein-2 (p < 0.001), alkaline phosphatase (p < 0.01), osteocalcin (p < 0.001), and type I collagen (p < 0.05) in newly formed bone, compared with the control. Immunohistochemistric assay supported the COMP-Ang1-facilitated induction of bone-specific markers. Furthermore, COMP-Ang1 augmented the mRNA expression of angiogenic factors, especially of platelet endothelial cell adhesion molecule 1, stromal cell-derived factor 1, and Tie-2 in the defect site. Our current findings demonstrate for the first time that a local delivery of recombinant COMP-Ang1 promotes bone formation in calvarial defects, which is coupled with enhanced angiogenesis and chemoattraction.

Bone regeneration around N-acetyl cysteine-loaded nanotube titanium dental implant in rat mandible.

New strategies involving drugs loading onto implant surfaces are required to enhance osseointegration and shorten healing time after implantation. In this study, we examined the feasibility of N-acetyl cysteine (NAC)-loaded nanotube titanium (NLN-Ti) implants as a potential drug delivery system. To determine the effect of NLN-Ti in in vitro and in vivo, viability and ROS formation was assessed and enzyme-linked immunosorbant assay (ELISA), Western blot, micro-computed tomography (µ-CT), hematoxylin and eoxin (H&E) staining and immunohistochemical (IHC) analysis were done. In vitro, cell viability was increased and inflammatory responses and reduced oxidative stress-related defense were decreased with MC 3T3-E1 cells exposed to a sustained release of NAC from NLN-Ti implants. Following NLN-Ti implant installation, µ-CT revealed an increase of newly formed bone volume and bone mineral density in the mandibles of Sprague Dawley rats. Relatively well formed new bone was demonstrated in close contact to the NLN-Ti implant surface by H&E staining. IHC revealed significantly higher expression of bone morphogenetic protein-2, -7 and heme oxygenase-1, and reduced expression of receptor activator of nuclear factor-kappa B ligand. The data indicate that NLN-Ti implants enhance osseointegration and highlight the value of the small animal model in assessing diverse biological responses to dental implants.

The antioxidant property of pachymic acid improves bone disturbance against AH plus-induced inflammation in MC-3T3 E1 cells.

INTRODUCTION: The cytotoxicity of resin-based sealer is influential on the inflammatory reaction and cell survival for oral periapical cells. In this study, pachymic acid as an antioxidant was investigated for the improvement of bone disturbance against AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany)-induced inflammation in MC-3T3 E1 cells. METHODS: AH Plus was prepared according to the manufacturer's instructions. Using mouse osteoblast cells (MC-3T3 E1), a specimen of AH Plus was eluted with the culture medium for 1 day and was diluted by 30%. The cellular cytotoxicity and reactive oxygen species formation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 2',7'-dichlorodihydrofluorescein diacetate with fluorescence-activated cell sorting. The secretion of proinflammatory cytokines was determined by an enzyme-linked immunosorbent assay, and the expression of inflammatory and osteogenic molecules was determined by immunoblotting. RESULTS: Cells with AH Plus elutes showed a decrease of cell viability and ALP activity. However, pachymic acid and N-acetyl-L-cysteine (control antioxidant) restored cell viability and ALP activity damaged by AH plus. The secretion of nitric oxide, tumor necrosis factor α, and interleukin-1ß were increased in AH Plus-stimulated MC-3T3 E1 cells, but pachymic acid suppressed its production. Furthermore, pachymic acid reduced the receptor activator of nuclear factor-κB ligand, cyclooxygenase-2, matrix metalloproteinase-2 and -9, increased bone morphogenetic protein-2 and -7, and runt-related transcription factor 2 despite AH Plus stimuli. In addition, pachymic acid affected the removal effect of reactive oxygen species formation as did N-acetyl-L-cysteine. More importantly, pachymic acid inhibited nuclear factor-κB translocation. CONCLUSIONS: The property of pachymic acid can mitigate the unfavorable conditions induced by AH Plus stimuli. Therefore, the use of pachymic acid is suggested to prevent the complications of oral diseases such as inflammation and alveolar destruction of the oral cavity.