Antioxidants Counteract Nicotine and Promote Migration via RacGTP in Oral Fibroblast Cells

Comparative effect of anthocyanin on proliferation and migration of human gingival fibroblasts in the absence or presence of nicotine

Background

Oral fibroblast malfunction can result in periodontal diseases. Nicotine can prolong the healing process as an irritant of oral tissues. Anthocyanins have been demonstrated to have potential benefits in preventing or treating smoking-related periodontal diseases. Cyanidin chloride's (CC's) potential in oral wound healing and the viability, proliferation, and migration of human gingival fibroblasts (HGFs) were examined in the presence and absence of nicotine by an in vitro study.

Methods

The effects of different nicotine concentrations (1, 2, 3, 4, and 5 mM) on the viability and proliferation of HGF cells were evaluated in the presence and absence of different CC concentrations (5, 10, 25, and 50 μM) using the quantitative MTT assay. The scratch test was performed to evaluate the migration of CC-treated cells in the presence of 2.5-mM nicotine.

Results

No cytotoxicity was observed at 1‒100 μM CC concentrations after 24, 48, and 72 hours of exposure to HGF cells. However, a concentration of 200 μM significantly reduced cell viability by about 20% at all the three-time intervals (P<0.05). Also, 3‒5-mM concentrations of nicotine significantly reduced cell viability in a dose- and time-dependent manner. Moreover, the understudied CC concentrations decreased nicotine's adverse effects on cell migration to some extent.

Conclusion

Although the understudied CC concentrations could not significantly reduce the adverse effects of understudied nicotine concentrations on the viability and proliferation of HGF cells, they were able to reduce the detrimental effects of nicotine on cell migration significantly.

In vitro fibroblasts viability and migration stimulation of Acalypha indica: an insight on wound healing activity

Background

The current study investigates the antioxidant activity of Acalypha indica aerial parts and root ethanolic extracts and explore whether these extracts will stimulate fibroblasts viability and ability to migrate.

Results

Aerial parts extract exhibited higher DPPH scavenging activity compared to root extract with IC50 of 62 µg/mL and 206 µg/mL, respectively. Both aerial parts and root extracts showed low cytotoxicity towards fibroblasts with 753 µg/mL LD50 for aerial parts and undetected LD50 for root extract. Additionally, aerial parts extract significantly induces fibroblasts proliferation up to 134%. Wound closure investigation showed a significant closure percentage for aerial parts compared to untreated control with 75% at 1 µg/mL and high closure percentage with 70% at 0.1 µg/mL for root extract compared to only 59% closure percentage for untreated control after 48 h of the study.

Conclusions

This study provided evidence for A. indica to have great wound healing potential. The finding builds the scientific background in future to utilise the high antioxidant activity of A. indica and its ability to stimulate fibroblasts migration and proliferation for further applications.

trans-Cinnamic acid, but not p-coumaric acid or methyl cinnamate, induces fibroblast migration through PKA- and p38-MAPK signalling pathways

AIM

Hydroxycinnamic acids their derivatives have various pharmacological properties. The hydroxycinnamic acid derivatives, methyl cinnamate, trans-cinnamic, and p-coumaric acids have been the object of study in the treatment of skin wounds. However, it is unclear whether these derivatives exert a direct beneficial effect on fibroblast function. In this study, we evaluated the effects of methyl cinnamate, trans-cinnamic, and p-coumaric acids on fibroblast migration in vitro.

MATERIALS AND METHODS

NIH 3T3 and L929 fibroblast cell lines were exposed to each drug at several concentrations and the effect on cell viability, cell cycle, and extracellular matrix production were assessed by MTT assay, flow cytometry, and immunofluorescence staining, respectively. The effect on cell migration was examined using scratch assay.

RESULTS

The results showed that hydroxycinnamic acid derivatives not affect cell viability, but increase fibroblast migration in the in vitro scratch-wound healing assay. They also induced an increase in S and G2/M phases accompanied by a decrease in the G0/G1 phase of the cell cycle. The cell proliferation inhibitor mitomycin C abolished the effect induced by p-coumaric acid and methyl cinnamate, indicating that only the trans-cinnamic acid stimulated migration. A transwell migration assay confirmed that trans-cinnamic acid-treated fibroblasts exhibited increased migration compared with untreated cells. trans-Cinnamic acid-induced fibroblast migration was decreased by PKA inhibitor and p38-MAPK inhibitor but not by JNK inhibitor. Additionally, trans-cinnamic acid-treated fibroblasts showed an increase in the production of laminin and collagen type I.

CONCLUSION

Our study showed that trans-cinnamic acid improves fibroblast migration and modulates extracellular matrix synthesis, indicating its potential for accelerating the healing process.

Challenges in Analyzing the Biological Effects of Resveratrol

The suggested health effects (e.g., disease prevention) of dietary bioactive compounds such as resveratrol are challenging to prove in comparison to man-made drugs developed for therapeutic purposes. Dietary bioactive compounds have multiple cellular targets and therefore have a variety of biological effects. Extrapolating the biological effects of dietary compounds from in vitro and in vivo animal experiments to humans may lead to over- or under-estimation of the effect and role of these compounds. The present paper will discuss a few of these challenges and suggest directions for future research. Questions we address include: (1) Is the combinatorial effect of resveratrol and other compounds real? (2) What are the real and relevant doses of resveratrol after administration? and (3) Is it possible to estimate the preventive effect of resveratrol by clinical trials using standard experimental designs? The examples concerning resveratrol taken from the scientific literature are mainly from 2010 and later. The challenges pointed out in this review are similar to most naturally occurring bioactive compounds.

Stimulating the proliferation, migration and lamellipodia of Schwann cells using low-dose curcumin

Transplantation of peripheral glia is being trialled for neural repair therapies, and identification of compounds that enhance the activity of glia is therefore of therapeutic interest. We have previously shown that curcumin potently stimulates the activity of olfactory glia. We have now examined the effect of curcumin on Schwann cell (SC) activities including proliferation, migration and the expression of protein markers. SCs were treated with control media and with different concentrations of curcumin (0.02-20 μM). Cell proliferation was determined by MTS assay and migration changes were determined by single live cell migration tracking. We found that small doses of curcumin (40 nM) dramatically increased the proliferation and migration in SCs within just one day. When compared with olfactory glia, curcumin stimulated SC proliferation more rapidly and at lower concentrations. Curcumin significantly increased the migration of SCs, and also increased the dynamic activity of lamellipodial waves which are essential for SC migration. Expression of the activated form of the MAP kinase p38 (p-p38) was significantly decreased in curcumin-treated SCs. These results show that curcumin's effects on SCs differ remarkably to its effects on olfactory glia, suggesting that subtypes of closely related glia can be differentially stimulated by curcumin. Overall these results demonstrate that the therapeutically beneficial activities of glia can be differentially enhanced by curcumin which could be used to improve outcomes of neural repair therapies.

Dietary antioxidants and their indispensable role in periodontal health

Periodontitis is an increasing area of interest due to its global prevalence. This inflammatory condition results due to the loss of the critical balance between the virulence factors produced by microorganisms and the inflammatory host response. A number of efforts have been made in the past to address this condition and regain periodontal health. Targeting the root cause by nonsurgical debridement has been considered the gold standard. However, research has shown the possible effects of nutrient deficiency and an imbalanced diet on the periodontium. Therefore, an effort toward the maintenance of optimal conditions as well as improvement of the oral health necessities the introduction of adjunctive nutritional therapy, which can benefit the patients. Antioxidants in the diet have some remarkable benefits and valuable properties that play an irreplaceable role in the maintenance of periodontal health. These have emerged as excellent adjuncts that can enhance the outcomes of conventional periodontal therapy. The aim of this review article is to highlight some of these dietary antioxidants that can make a notable difference by striking a balance between health and disease.

Phloretin-induced cytoprotective effects on mammalian cells: A mechanistic view and future directions

Phloretin (C15 H14 O5 ), a dihydrochalcone flavonoid, is mainly found in fruit, leaves, and roots of apple tree. Phloretin exerts antioxidant, anti-inflammatory, and anti-tumor activities in mammalian cells through mechanisms that have been partially elucidated throughout the years. Phloretin bioavailability is well known in humans, but still remains to be better studied in experimental animals, such as mouse and rat. The focus of the present review is to gather information regarding the mechanisms involved in the phloretin-elicited effects in different in vitro and in vivo experimental models. Several manuscripts were analyzed and data raised by authors were described and discussed here in a mechanistic manner. Comparisons between the effects elicited by phloretin and phloridzin were made whenever possible, as well as with other polyphenols, clarifying questions about the use of phloretin as a potential therapeutic agent. Toxicological aspects associated to phloretin exposure were also discussed here. Furthermore, a special section containing future directions was created as a suggestive guide towards the elucidation of phloretin-related actions in mammalian cells and tissues.

Activation of Receptor Activator of Nuclear Factor-κB Ligand and Matrix Metalloproteinase Production in Periodontal Fibroblasts by Endothelin Signaling

BACKGROUND

Periodontitis is a group of inflammatory diseases affecting the tissues supporting the teeth that will progressively cause the loss of alveolar bone and periodontal ligaments and eventually the dentition. Activation of osteoclast activity by receptor activator of nuclear factor-κB ligand (RANKL) and released enzymes such as matrix metalloproteinases (MMPs) are among the factors involved in the breakdown of the periodontium. However, the mechanisms regulating their production in periodontitis are poorly understood. Endothelin signaling via the activation of the endothelin-A receptor (EDNRA) by endothelin-1 may play a role in the disease because the expression of the receptor and ligand is elevated in the periodontal tissues of patients with periodontitis.

METHODS

Cultured primary human periodontal fibroblasts were treated with 20 and 100 nM endothelin-1 for 6 and 24 hours and then collected to assess MMP and RANKL production by immunoblotting. Inhibitors were used to identify the molecular pathways activated by EDNRA in these cells.

RESULTS

Endothelin-1 stimulated the production of MMP1, MMP8, and RANKL in a dose- and time-dependent manner; blocking EDNRA function with the antagonist TBC3214 inhibited the response, although EDNRA activation had no effects on osteoprotegerin production. These mechanistic studies indicate that EDNRA activates phospholipase C, which then 1) increases the MMP1 protein levels through activation of the extracellular signal-regulated kinase mitogen-activated protein kinase-dependent pathway and 2) upregulates RANKL by a different pathway.

CONCLUSION

These results suggest that EDNRA may function in the breakdown of the periodontal tissues associated with periodontitis by promoting the protein expression of MMPs and RANKL via the phospholipase C pathway.

Fibroblastic Transformation of Corneal Keratocytes by Rac Inhibition is Modulated by Extracellular Matrix Structure and Stiffness

The goal of this study was to investigate how alterations in extracellular matrix (ECM) biophysical properties modulate corneal keratocyte phenotypes in response to specific wound healing cytokines and Rho GTPases. Rabbit corneal keratocytes were plated within standard collagen matrices (2.5 mg/mL) or compressed collagen matrices (~100 mg/mL) and cultured in serum-free media, PDGF BB, IGF, FGF2 or TGFβ1, with or without the Rac1 inhibitor NSC23766 and/or the Rho kinase inhibitor Y-27632. After 1 to 4 days, cells were labeled for F-actin and imaged using confocal microscopy. Keratocytes within standard collagen matrices (which are highly compliant) maintained a dendritic phenotype following culture in serum-free media, PDGF, IGF and FGF, but developed stress fibers in TGFβ1. Keratocytes within compressed collagen (which has high stiffness and low porosity) maintained a dendritic phenotype following culture in serum-free media, PDGF and IGF, but developed stress fibers in both FGF and TGFβ1. The Rac inhibitor had no significant impact on growth factor responses in compliant matrices. Within compressed collagen matrices however, the Rac inhibitor induced fibroblastic transformation in serum-free media, PDGF and IGF. Fibroblast and myofibroblast transformation was blocked by Rho kinase inhibition. Overall, keratocyte growth factor responses appear to be regulated by both the interplay between Rho and Rac signaling, and the structural and mechanical properties of the ECM.

Knockdown of SVCT2 impairs in-vitro cell attachment, migration and wound healing in bone marrow stromal cells

Bone marrow stromal cell (BMSC) adhesion and migration are fundamental to a number of pathophysiologic processes, including fracture and wound healing. Vitamin C is beneficial for bone formation, fracture repair and wound healing. However, the role of the vitamin C transporter in BMSC adhesion, migration and wound healing is not known. In this study, we knocked-down the sodium-dependent vitamin C transporter, SVCT2, the only known transporter of vitamin C in BMSCs, and performed cell adhesion, migration, in-vitro scratch wound healing and F-actin re-arrangement studies. We also investigated the role of oxidative stress on the above processes. Our results demonstrate that both oxidative stress and down-regulation of SVCT2 decreased cell attachment and spreading. A trans-well cell migration assay showed that vitamin C helped in BMSC migration and that knockdown of SVCT2 decreased cell migration. In the in-vitro scratch wound healing studies, we established that oxidative stress dose-dependently impairs wound healing. Furthermore, the supplementation of vitamin C significantly rescued the BMSCs from oxidative stress and increased wound closing. The knockdown of SVCT2 in BMSCs strikingly decreased wound healing, and supplementing with vitamin C failed to rescue cells efficiently. The knockdown of SVCT2 and induction of oxidative stress in cells produced an alteration in cytoskeletal dynamics. Signaling studies showed that oxidative stress phosphorylated members of the MAP kinase family (p38) and that vitamin C inhibited their phosphorylation. Taken together, these results indicate that both the SVCT2 transporter and oxidative stress play a vital role in BMSC attachment, migration and cytoskeletal re-arrangement. BMSC-based cell therapy and modulation of SVCT2 could lead to a novel therapeutic approach that enhances bone remodeling, fracture repair and wound healing in chronic disease conditions.

The effect of α-tocopherol and selenium on human gingival fibroblasts and periodontal ligament fibroblasts in vitro

BACKGROUND

The aim of the present study is to evaluate the effect of α-tocopherol and selenium on gingival fibroblasts (GFs) and periodontal ligament fibroblasts (PDLFs) in terms of proliferation, basic fibroblast growth factor (bFGF) release, collagen type I synthesis, and wound healing.

METHODS

Primary cultures of human GFs and PDLFs were isolated. Four test groups and a control group free of medication was formed. In group E, 60 μM α-tocopherol was used, and in groups ES1, ES2, and ES3, the combination of 60 μM α-tocopherol with 5 × 10(-9) M, 10 × 10(-9) M, and 50 × 10(-9) M selenium was used, respectively. Viability, proliferation, bFGF, and collagen type I synthesis from both cell types were evaluated at 24, 48, and 72 hours, and healing was compared on a new wound-healing model at 12, 24, 36, 48, and 72 hours.

RESULTS

α-Tocopherol alone significantly increased the healing rate of PDLFs at 12 hours and increased bFGF and collagen type I release from GFs and PDLFs at 24, 48, and 72 hours. The α-tocopherol/selenium combination significantly enhanced the proliferation rate of both cells at 48 hours, decreased the proliferation of PDLFs at 72 hours, and increased the healing rate of GFs at 12 hours and PDLFs at 12 and 48 hours. bFGF and collagen type I synthesis was also increased in both cell types at 24, 48, and 72 hours by α-tocopherol/selenium combination.

CONCLUSION

α-Tocopherol and α-tocopherol/selenium combination is able to accelerate the proliferation rate and wound-healing process and increase the synthesis of bFGF and collagen type I from both GFs and PDLFs.

Effects of sirtuin 1 activation on nicotine and lipopolysaccharide-induced cytotoxicity and inflammatory cytokine production in human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Although sirtuin 1 (SIRT1) over-expression and resveratrol exert anti-inflammatory and proinflammatory effects, their effects and the mechanism of action on human gingival fibroblast (HGF)-mediated inflammation are unknown. The aim of this study was to demonstrate the effects of activating SIRT1 using resveratrol and recombinant adenovirus encoding SIRT1 (Ad-SIRT1) on the expression of proinflammatory cytokines and to elucidate its mechanism of action of lipopolysaccharide (LPS) and nicotine stimulated-HGF.

MATERIAL AND METHODS

Cytotoxicity and the production of reactive oxygen species (ROS) were measured using the 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. The amount of prostaglandin E2 (PGE2 ) released into the culture medium was measured by radioimmunoassay. mRNA and protein levels were analyzed using RT-PCR and western blotting, respectively.

RESULTS

Nicotine and LPS up-regulated the expression of SIRT1 mRNA and SIRT1 protein in a time- and concentration-dependent manner. Resveratrol and Ad-SIRT1 decreased LPS and nicotine-induced cytotoxicity, ROS and PGE2 production, and expression of cyclooxygenase-2 in HGFs. Resveratrol and Ad-SIRT1 inhibited nicotine and LPS-mediated protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K), p38, ERK, JNK, MAPK and nuclear factor-kappa B (NF-κB) activation.

CONCLUSION

This study is the first to show that the anti-inflammatory and cytoprotective effects of SIRT1 activation in HGFs occur through the PKC, PI3K, MAPK and NF-κB pathways.

Effects of cigarette smoke and nicotine on cell viability, migration and myofibroblastic differentiation

BACKGROUND AND OBJECTIVE

Several studies have analysed the role of nicotine as a prominent agent affecting wound repair in smokers. However, tobacco smoke contains several components that may alter gingival wound healing. The present study aimed to analyse the roles of cigarette smoke condensate (CSC) and nicotine on cell viability, cell migration/invasion and myofibroblastic differentiation using primary cultures of human gingival fibroblasts.

MATERIAL AND METHODS

To compare the effects of CSC and nicotine, gingival fibroblasts were stimulated with CSC (0.4–500 lg/mL) and the corresponding nicotine concentrations (0.025–32 lg/mL) present in research cigarettes (1R3F). Cell viability was evaluated through the MTS assay. Cell migration and invasion were assessed through scratch wound assays, collagen nested matrices and trans well migration. a-Smooth muscle actin production was evaluated by western blotting.

RESULTS

Cigarette smoke condensate at 50 lg/mL induced a moderate increase in cell viability, whereas the corresponding nicotine concentration (3.2 lg/mL) did not produce this response. Cigarette smoke condensate at 250 lg/mL, but not nicotine at 16 lg/mL (the corresponding nicotine concentration), induced cell death. Both nicotine and CSC stimulated cell migration (50 lg/mL CSC; 3.2 lg/mL nicotine). At 150 lg/mL, CSC inhibited cell migration; however, the corresponding concentration of nicotine (9.6 lg/mL), did not have this effect. Although both nicotine and CSC inhibited a-smooth muscle actin production, only the latter induced a statistically significant effect on this response.

CONCLUSION

Cigarette smoke condensate may stimulate cell survival and migration at low concentrations and inhibit these cell responses at higher levels of exposure. Moreover, CSC may interfere in myofibroblastic differentiation.These results show that cigarette smoke, but not nicotine, may significantly alter cell viability, cell migration and myofibroblastic differentiation in gingival mesenchymal cells.

Cell-matrix and cell-cell interactions of human gingival fibroblasts on three-dimensional nanofibrous gelatin scaffolds

An in-depth understanding of the interactions between cells and three-dimensional (3D) matrices (scaffolds) is pivotal to the development of novel biomaterials for tissue regeneration. However, it remains a challenge to find suitable biomimetic substrates and tools to observe cell-material and cell-cell interactions on 3D matrices. In the present study, we developed biomimetic nanofibrous 3D gelatin scaffolds (3D-NF-GS) and utilized confocal microscopy combined with a quantitative analysis approach to explore cell-matrix and cell-cell interactions on the 3D-NF-GS. Human gingival fibroblasts (HGFs) migrated throughout the 3D-NF-GS by 5 days and formed stable focal adhesions by 14 days. The focal adhesions were detected using integrin-β1, phospho-paxillin and vinculin expression, which were quantified from specific wavelength photon data generated using a spectral separation confocal microscope. As the cells became more confluent after 14 days of culture, cell-cell communication via gap junctions increased significantly. Collagen I matrix production by HGFs on 3D-NF-GS was visualized and quantified using a novel approach incorporating TRITC label in the scaffolds. Based on confocal microscopy, this study has developed qualitative and quantitative methods to study cell-matrix and cell-cell interactions on biomimetic 3D matrices, which provides valuable insights for the development of appropriate scaffolds for tissue regeneration.

Effect of the intake of resveratrol, resveratrol phosphate, and catechin-rich grape seed extract on markers of oxidative stress and gene expression in adult obese subjects

BACKGROUND

The preventive effect of resveratrol (RES) on the development of human diseases has been verified by numerous epidemiological studies. Resveratrol triphosphate (RTP) is a stable derivative of RES in which phosphate groups protect the phenolic groups.

AIMS

This study compared the effect of RTP on biochemical and molecular markers of oxidative stress to equimolar doses (0.66 mmol) of RES and catechin-rich grape seed extract (CGSE) in a model of oxidative and metabolic stress associated with obesity in humans.

METHODS

Thirty-two obese subjects (BMI between 30 and 40) were enrolled. They all received 1 capsule of placebo/day for 28 days before being randomly devised into three arms receiving 1 capsule/day of RES, CGSE, or RTP during the following consecutive 28 days. Blood samples were collected at baseline, after the end of placebo intake, and after the end of the investigational product intake. Biochemical parameters of oxidative stress and blood expression of 200 redox-related genes were determined at each time point.

RESULTS

RTP and CGSE showed better antioxidant activities compared to RES and induced important modulations of gene expression.

CONCLUSION

The results suggest that RTP and CGSE could contribute to a significant reduction of oxidative stress in obese subjects.

Cigarette smoke extract induces select matrix metalloproteinases and integrin expression in periodontal ligament fibroblasts

BACKGROUND

The periodontal ligament (PDL) is the connective tissue that anchors the cementum of the teeth to the alveolar bone. PDL fibroblasts are responsible for the production of collagen and remodeling of the PDL. Periodontal disease is increased among smokers in both incidence and severity. This study examines the direct effect of smoking on PDL fibroblasts and their production of various matrix components and remodeling enzymes.

METHODS

PDL cells were plated for 1 day and then treated with various concentrations of cigarette smoke extract (CSE). Survival of PDL cells was quantified after exposure to CSE, and their ability to contract three-dimensional collagen gels was examined. Changes in transcript expression after CSE treatment was compared using reverse transcription-polymerase chain reaction analysis for matrix metalloproteinases (MMPs), collagens, and integrins.

RESULTS

Treatment with CSE-induced cell death at concentrations of ≥5%. PDL-cell-induced collagen gel contraction was reduced at concentrations of 1.5% CSE. Treatment with CSE selectively increased the expression of collagen Vα3 and decreased collagen XIα1. CSE increased the expression of MMP1 and MMP3 and, to a lesser extent, MMP2 and MMP8. CSE also increased the expression of integrins α1, α2, and α10 (collagen receptors) and α9 (a tenascin receptor).

CONCLUSIONS

This study shows that cigarette smoking has local effects on the cells of the PDL. CSE reduced survival of PDL cells and their ability to contract collagen matrices. CSE also altered the expression of molecules known to provide the structural integrity of the ligament by altering collagen synthesis and remodeling as well as cell adhesion.

Nicotine and lipopolysaccharide stimulate the production of MMPs and prostaglandin E2 by hypoxia-inducible factor-1α up-regulation in human periodontal ligament cells

BACKGROUND AND OBJECTIVE

  Although hypoxia-inducible factor 1α (HIF-1α) is up-regulated in the periodontal pockets of periodontitis patients, the expression and precise molecular mechanisms of HIF-1α remain unknown in human periodontal ligament cells (PDLCs). The aim of this study was to explore the effects, as well as the signaling pathway, of nicotine and lipopolysaccharide (LPS) on the expression of HIF-1α and on the production of its target genes, including cyclooxygenase-2 (COX-2)-derived prostaglandin E(2) (PGE(2) ), MMP-2 and MMP-9 in PDLCs.

MATERIAL AND METHODS

  The expression of COX-2 and HIF-1α proteins was evaluated using western blotting. The production of PGE(2) and MMPs was evaluated using enzyme immunoassays and zymography, respectively.

RESULTS

  LPS and nicotine synergistically induced the production of PGE(2) , MMP-2 and MMP-9, and increased the expression of MMP-2, MMP-9, COX-2 and HIF-1α proteins. Inhibition of HIF-1α activity by chetomin or knockdown of HIF1α gene expression by small interfering RNA markedly attenuated the production of LPS- and nicotine-stimulated PGE(2) and MMPs, as well as the expression of COX-2 and HIF-1α. Furthermore, pretreatment with inhibitors of COX-2, p38, extracellular signal-regulated kinase, Jun N-terminal kinase, protein kinase C, phosphatidylinositol 3-kinase and nuclear factor-kappaB decreased the expression of nicotine- and LPS-induced HIF-1α and COX-2, as well as the activity of PGE(2) and MMPs.

CONCLUSION

  These data demonstrate novel mechanisms by which nicotine and LPS promote periodontal tissue destruction, and provide further evidence that HIF-1α is a potential target in periodontal disease associated with smoking and dental plaque.

Implications of cultured periodontal ligament cells for the clinical and experimental setting: a review

The periodontal ligament (PDL) is a key contributor to the process of regeneration of the periodontium. The heterogeneous nature of the PDL tissue, its development during early adulthood, and the different conditions to which the PDL tissue is exposed to in vivo impart on the PDL unique characteristics that may be of consequence during its cultivation in vitro. Several factors affecting the in vivo setting influence the behaviour of PDL fibroblasts in culture. The purpose of this review is to address distinct factors that influence the behaviour of PDL fibroblasts in culture -in vivo-in vitro transitions, cell identification/isolation markers, primary PDL cultures and cell lines, tooth-specific factors, and donor-specific factors. Based on the reviewed studies, the authors recommendations include the use of several identification markers to confirm cell identity, use of primary cultures at early passage to maintain unique PDL heterogeneic characteristics, and noting donor conditions such as age, systemic health status, and tooth health status. Continued efforts will expand our understanding of the in vitro and in vivo behaviour of cells, with the goal of orchestrating optimal periodontal regeneration. This understanding will lead to improved evidence-based rationales for more individualized and predictable periodontal regenerative therapies.