MicroRNA-155 (miR-155) as an accurate biomarker of periodontal status and coronary heart disease severity: a case-control study.

BACKGROUND: Increasing evidence supports associations between periodontal disease and coronary heart disease (CHD). This case-control study evaluated whether inflammatory regulator, microRNA-155 (miR-155), could be utilised as a biomarker of periodontitis and/or CHD. METHODS: Of 120 participants, 30 patients had clinically healthy periodontium (controls, C), 30 patients had generalized periodontitis (P), 30 patients had CHD and clinically healthy periodontium (AS-C); and 30 patients had CHD with generalized periodontitis (AS-P). Patient demographic and periodontal characteristics (plaque index, bleeding on probing, probing pocket depth and clinical attachment loss), were collected. Patient whole blood and saliva levels of miR-155 and pro-inflammatory cytokine (interleukin-1ß), were quantified by quantitative real time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). One-way ANOVA with post-hoc Tukey test was used to determine differences among the four groups. Chi Square test was used for participant gender comparisons. Pearson correlation tests and multiple linear regression analyses were used to assess associations between the demographic and clinical variables analysed, versus IL-1ß and miR-155 levels. miR-155 and IL-1ß accuracy in differentiating healthy versus other patient groups were analysed using receiver operating characteristic (ROC) curves, by calculating area under the curve (AUC) values and sensitivity and specificity cut-off points using Youden's index. Statistical tests of sensitivity and specificity were conducted using the McNemar test. RESULTS: Whole blood miR-155 levels were elevated in periodontitis/non-periodontitis patients with CHD (AS-P, AS-C), and periodontitis patients alone (P) (p < 0.001). Receiver operating characteristic (ROC) and area under the curve (AUC) analyses confirmed miR-155 accuracy in discriminating P, AS-C and AS-P groups (AUC 0.6861-0.9944, p < 0.0001-0.05), coupled with high sensitivity (76.7-100.0%), specificity (53.3-96.7%) and cut-off points (> 0.955- > 2.915 a.u.; p < 0.0001). miR-155 levels further distinguished between CHD (AS-C, AS-P) and periodontitis (P) patients (AUC ≥ 0.8378, sensitivity ≥ 88.7%, specificity ≥ 73.3%, cut-off > 2.82 a.u; p < 0.0001), and between AS-C and AS-P patients (AUC 0.7578, sensitivity 80.0%, specificity 50.0%, cut-off > 7.065 a.u; p < 0.001). Subsequent analyses identified positive correlations between miR-155 and the various patient demographics, salivary interleukin-1ß and periodontal parameters assessed. CONCLUSIONS: This study advocates miR-155 as an accurate diagnostic/prognostic biomarker of periodontitis and/or CHD severity, thereby improving detection and treatment for both conditions.

Variation in human dental pulp stem cell ageing profiles reflect contrasting proliferative and regenerative capabilities.

BACKGROUND: Dental pulp stem cells (DPSCs) are increasingly being recognized as a viable cell source for regenerative medicine. Although significant variations in their ex vivo expansion are well-established, DPSC proliferative heterogeneity remains poorly understood, despite such characteristics influencing their regenerative and therapeutic potential. This study assessed clonal human DPSC regenerative potential and the impact of cellular senescence on these responses, to better understand DPSC functional behaviour. RESULTS: All DPSCs were negative for hTERT. Whilst one DPSC population reached >80 PDs before senescence, other populations only achieved <40 PDs, correlating with DPSCs with high proliferative capacities possessing longer telomeres (18.9 kb) than less proliferative populations (5-13 kb). High proliferative capacity DPSCs exhibited prolonged stem cell marker expression, but lacked CD271. Early-onset senescence, stem cell marker loss and positive CD271 expression in DPSCs with low proliferative capacities were associated with impaired osteogenic and chondrogenic differentiation, favouring adipogenesis. DPSCs with high proliferative capacities only demonstrated impaired differentiation following prolonged expansion (>60 PDs). CONCLUSIONS: This study has identified that proliferative and regenerative heterogeneity is related to contrasting telomere lengths and CD271 expression between DPSC populations. These characteristics may ultimately be used to selectively screen and isolate high proliferative capacity/multi-potent DPSCs for regenerative medicine exploitation.

Hepatocyte Growth Factor Mediates Enhanced Wound Healing Responses and Resistance to Transforming Growth Factor-ß1-Driven Myofibroblast Differentiation in Oral Mucosal Fibroblasts.

Oral mucosal wounds are characterized by rapid healing with minimal scarring, partly attributable to the "enhanced" wound healing properties of oral mucosal fibroblasts (OMFs). Hepatocyte growth factor (HGF) is a pleiotropic growth factor, with potential key roles in accelerating healing and preventing fibrosis. HGF can exist as full-length or truncated (HGF-NK), NK1 and NK2 isoforms. As OMFs display elevated HGF expression compared to dermal fibroblasts (DFs), this study investigated the extent to which HGF mediates the preferential cellular functions of OMFs, and the influence of pro-fibrotic, transforming growth factor-ß1 (TGF-ß1) on these responses. Knockdown of HGF expression in OMFs by short-interfering RNA (siHGF) significantly inhibited OMF proliferative and migratory responses. Supplementation with exogenous TGF-ß1 also significantly inhibited proliferation and migration, concomitant with significantly down-regulated HGF expression. In addition, knockdown abrogated OMF resistance to TGF-ß1-driven myofibroblast differentiation, as evidenced by increased α-smooth muscle actin (α-SMA) expression, F-actin reorganisation, and stress fibre formation. Responses were unaffected in siHGF-transfected DFs. OMFs expressed significantly higher full-length HGF and NK1 levels compared to patient-matched DFs, whilst NK2 expression was similar in both OMFs and DFs. Furthermore, NK2 was preferentially expressed over NK1 in DFs. TGF-ß1 supplementation significantly down-regulated full-length HGF and NK1 expression by OMFs, while NK2 was less affected. This study demonstrates the importance of HGF in mediating "enhanced" OMF cellular function. We also propose that full-length HGF and HGF-NK1 convey desirable wound healing properties, whilst fibroblasts preferentially expressing more HGF-NK2 readily undergo TGF-ß1-driven differentiation into myofibroblasts.

Contrasting host immuno-inflammatory responses to bacterial challenge within venous and diabetic ulcers.

Within chronic wounds, the relationship between the clinical diagnosis of infection and bacterial/immuno-inflammatory responses is imprecise. This study prospectively examined the interrelationship between clinical, microbiological, and proinflammatory biomarker levels between chronic venous leg ulcers (CVLUs) and diabetic foot ulcers (DFUs). Wound swabs and fluids were collected from CVLUs (n = 18) and DFUs (n = 15) and diagnosed clinically as noninfected or infected; and qualitative/quantitative microbiology was performed. CVLU and DFU fluids were also analyzed for cytokine, growth factor, receptor, proteinase/proteinase inhibitor; and oxidative stress biomarker (protein carbonyl, malondialdehyde, and antioxidant capacity) levels. While no correlations existed between clinical diagnosis, microbiology, or biomarker profiles, increasing bacterial bioburden (≥10(7) colony-forming unit/mL) was associated with significant alterations in cytokine, growth factor, and receptor levels. These responses contrasted between ulcer type, with elevated and decreased cytokine, growth factor, and receptor levels in CVLUs and DFUs with increasing bioburden, respectively. Despite proteinase biomarkers exhibiting few differences between CVLUs and DFUs, significant elevations in antioxidant capacities correlated with increased bioburden in CVLU fluids, but not in DFUs. Furthermore, oxidative stress biomarker levels were significantly elevated in all DFU fluids compared with CVLUs. This study provides further insight into the contrasting disease-specific host responses to bacterial challenge within infected CVLUs and DFUs.

Differential influence of fluoride concentration on the synthesis of bone matrix glycoproteins within mineralizing bone cells in vitro.

OBJECTIVE: This study investigated the influence of fluoride levels on the temporal synthesis of bone-associated glycoproteins, which have been assigned prominent roles in regulating crystal growth, size and shape during the mineralization process. MATERIALS AND METHODS: Bone marrow stromal cells were isolated from male Wistar rats and cultured under mineralizing conditions, supplemented with 0 M, 10(-7) M or 10(-5) M sodium fluoride. The presence of bone-associated glycoproteins was examined 2-13 days post-reseeding by immunocytochemical localization. Results: All bone-associated glycoproteins increased in 10(-7) M fluoride, compared to untreated controls, particularly at days 6 and 13 in culture. Conversely, higher 10(-5) M fluoride concentrations decreased glycoprotein levels, compared to controls. CONCLUSIONS: Results highlight a differential effect of fluoride concentration on glycoprotein synthesis by osteoblasts.

Tigilanol Tiglate-Induced Changes in Secretome Profiles Alter C-Met Phosphorylation and Cell Surface Protein Expression in H357 Head and Neck Cancer Cells.

Tigilanol tiglate (TT, also known as EBC-46) is a novel, plant-derived diterpene ester possessing anticancer and wound-healing properties. Here, we show that TT-evoked PKC-dependent S985 phosphorylation of the tyrosine kinase MET leads to subsequent degradation of tyrosine phosphorylated p-Y1003 and p-Y1234/5 MET species. PKC inhibition with BIM-1 blocked S985 phosphorylation of MET and led to MET cell surface accumulation. Treatment with metalloproteinase inhibitors prevented MET-ECD release into cell culture media, which was also blocked by PKC inhibitors. Furthermore, unbiased secretome analysis, performed using TMT-technology, identified additional targets of TT-dependent release of cell surface proteins from H357 head and neck cancer cells. We confirm that the MET co-signalling receptor syndecan-1 was cleaved from the cell surface in response to TT treatment. This was accompanied by rapid cleavage of the cellular junction adhesion protein Nectin-1 and the nerve growth factor receptor NGFRp75/TNFR16. These findings, that TT is a novel negative regulator of protumorigenic c-MET and NGFRp75/TNFR16 signalling, as well as regulating Nectin-1-mediated cell adhesion, further contribute to our understanding of the mode of action and efficacy of TT in the treatment of solid tumours.

Evidence for Natural Products as Alternative Wound-Healing Therapies.

Chronic, non-healing wounds represent a significant area of unmet medical need and are a growing problem for healthcare systems around the world. They affect the quality of life for patients and are an economic burden, being difficult and time consuming to treat. They are an escalating problem across the developed world due to the increasing incidence of diabetes and the higher prevalence of ageing populations. Effective treatment options are currently lacking, and in some cases chronic wounds can persist for years. Some traditional medicines are believed to contain bioactive small molecules that induce the healing of chronic wounds by reducing excessive inflammation, thereby allowing re-epithelisation to occur. Furthermore, many small molecules found in plants are known to have antibacterial properties and, although they lack the therapeutic selectivity of antibiotics, they are certainly capable of acting as topical antiseptics when applied to infected wounds. As these molecules act through mechanisms of action distinct from those of clinically used antibiotics, they are often active against antibiotic resistant bacteria. Although there are numerous studies highlighting the effects of naturally occurring small molecules in wound-healing assays in vitro, only evidence from well conducted clinical trials can allow these molecules or the remedies that contain them to progress to the clinic. With this in mind, we review wound-healing natural remedies that have entered clinical trials over a twenty-year period to the present. We examine the bioactive small molecules likely to be in involved and, where possible, their mechanisms of action.

Role of Enzymic Antioxidants in Mediating Oxidative Stress and Contrasting Wound Healing Capabilities in Oral Mucosal/Skin Fibroblasts and Tissues.

Unlike skin, oral mucosal wounds are characterized by rapid healing and minimal scarring, attributable to the "enhanced" healing properties of oral mucosal fibroblasts (OMFs). As oxidative stress is increasingly implicated in regulating wound healing outcomes, this study compared oxidative stress biomarker and enzymic antioxidant profiles between patient-matched oral mucosal/skin tissues and OMFs/skin fibroblasts (SFs) to determine whether superior oral mucosal antioxidant capabilities and reduced oxidative stress contributed to these preferential healing properties. Oral mucosa and skin exhibited similar patterns of oxidative protein damage and lipid peroxidation, localized within the lamina propria/dermis and oral/skin epithelia, respectively. SOD1, SOD2, SOD3 and catalase were primarily localized within epithelial tissues overall. However, SOD3 was also widespread within the lamina propria localized to OMFs, vasculature and the extracellular matrix. OMFs were further identified as being more resistant to reactive oxygen species (ROS) generation and oxidative DNA/protein damage than SFs. Despite histological evaluation suggesting that oral mucosa possessed higher SOD3 expression, this was not fully substantiated for all OMFs examined due to inter-patient donor variability. Such findings suggest that enzymic antioxidants have limited roles in mediating privileged wound healing responses in OMFs, implying that other non-enzymic antioxidants could be involved in protecting OMFs from oxidative stress overall.

Synergistic activity of pomegranate rind extract and Zn (II) against Candida albicans under planktonic and biofilm conditions, and a mechanistic insight based upon intracellular ROS induction.

Candida albicans (C. albicans) is an opportunistic pathogen, which causes superficial infection and can lead to mortal systemic infections, especially in immunocompromised patients. The incidence of C. albicans infections is increasing and there are a limited number of antifungal drugs used in treatment. Therefore, there is an urgent need for new and alternative antifungal drugs. Pomegranate rind extract (PRE) is known for its broad-spectrum antimicrobial activities, including against C. albicans and recently, PRE and Zn (II) have been shown to induce synergistic antimicrobial activity against various microbes. In this study, the inhibitory activities of PRE, Zn (II) and PRE in combination with Zn (II) were evaluated against C. albicans. Antifungal activities of PRE and Zn (II) were evaluated using conventional microdilution methods and the interaction between these compounds was assessed by in vitro checkerboard and time kill assays in planktonic cultures. The anti-biofilm activities of PRE, Zn (II) and PRE in combination with Zn (II) were assessed using confocal laser scanning microscopy, with quantitative analysis of biofilm biomass and mean thickness analysed using COMSTAT2 analysis. In addition, antimicrobial interactions between PRE and Zn (II) were assayed in terms reactive oxygen species (ROS) production by C. albicans. PRE and Zn (II) showed a potent antifungal activity against C. albicans, with MIC values of 4 mg/mL and 1.8 mg/mL, respectively. PRE and Zn (II) in combination exerted a synergistic antifungal effect, as confirmed by the checkerboard and time kill assays. PRE, Zn (II) and PRE and Zn (II) in combination gave rise to significant reductions in biofilm biomass, although only PRE caused a significant reduction in mean biofilm thickness. The PRE and Zn (II) in combination caused the highest levels of ROS production by C. albicans, in both planktonic and biofilm forms. The induction of excess ROS accumulation in C. albicans may help explain the synergistic activity of PRE and Zn (II) in combination against C. albicans in both planktonic and biofilm forms. Moreover, the data support the potential of the PRE and Zn (II) combination as a novel potential anti-Candida therapeutic system.

Dental Pulp Stem Cell Heterogeneity: Finding Superior Quality "Needles" in a Dental Pulpal "Haystack" for Regenerative Medicine-Based Applications.

Human dental pulp stem/stromal cells (hDPSCs) derived from the permanent secondary dentition are recognised to possess certain advantageous traits, which support their potential use as a viable source of mesenchymal stem/stromal cells (MSCs) for regenerative medicine-based applications. However, the well-established heterogeneous nature of hDPSC subpopulations, coupled with their limited numbers within dental pulp tissues, has impeded our understanding of hDPSC biology and the translation of sufficient quantities of these cells from laboratory research, through successful therapy development and clinical applications. This article reviews our current understanding of hDPSC biology and the evidence underpinning the molecular basis of their heterogeneity, which may be exploited to distinguish individual subpopulations with specific or superior characteristics for regenerative medicine applications. Pertinent unanswered questions which still remain, regarding the developmental origins, hierarchical organisation, and stem cell niche locations of hDPSC subpopulations and their roles in hDPSC heterogeneity and functions, will further be explored. Ultimately, a greater understanding of how key features, such as specific cell surface, senescence and other relevant genes, and protein and metabolic markers, delineate between hDPSC subpopulations with contrasting stemness, proliferative, multipotency, immunomodulatory, anti-inflammatory, and other relevant properties is required. Such knowledge advancements will undoubtedly lead to the development of novel screening, isolation, and purification strategies, permitting the routine and effective identification, enrichment, and expansion of more desirable hDPSC subpopulations for regenerative medicine-based applications. Furthermore, such innovative measures could lead to improved cell expansion, manufacture, and banking procedures, thereby supporting the translational development of hDPSC-based therapies in the future.

Anti-Fibrotic Potential of Tomentosenol A, a Constituent of Cerumen from the Australian Native Stingless Bee, Tetragonula carbonaria.

Bioactivity-guided fractionation was used to isolate two compounds, tomentosenol A (1) and torellianone A (2), from a cerumen extract from Tetragonula carbonaria. The anti-fibrotic activity of these compounds was examined using human cultured neonatal foreskin fibroblasts (NFF) and immortalised keratinocytes (HaCaTs). Tomentosenol A (1), inhibited NFF and HaCaT cell proliferation and prevented NFF and HaCaT scratch wound repopulation at 12.5-25 µM concentrations. These inhibitory effects were associated with reduced cell viability, determined by tetrazolium dye (MTT) and sulforhodamine B (SRB) assays. Compound 1 further inhibited transforming growth factor-ß1 (TGF-ß1)-stimulated, NFF-myofibroblast differentiation and soluble collagen production; and was an effective scavenger of the model oxidant, 2,2-diphenyl-1-picrylhydrazyl (DPPH·), with an EC50 value of 44.7 ± 3.1 µM. These findings reveal significant anti-fibrotic potential for cerumen-derived tomentosenol A (1).

Ficus septica exudate, a traditional medicine used in Papua New Guinea for treating infected cutaneous ulcers: in vitro evaluation and clinical efficacy assessment by cluster randomised trial.

BACKGROUND AND OBJECTIVES: Infected cutaneous ulcers are major health problems for children living in rural areas of Papua New Guinea. The inaccessibility of affected populations and lack of access to basic healthcare, make a local plant-based therapy an attractive treatment option. We assessed Ficus septica exudate in biological assays relevant to wound healing. We then carried out a clinical trial to determine the exudate's efficacy in healing small cutaneous ulcers compared with Savlon antiseptic cream, and soap and water washing. METHODS: Pre-clinical in vitro assessment of the exudate was carried out using assays to monitor the pro-inflammatory responses of M1 macrophages and neutrophils, antibacterial assays using known ulcer pathogens, an Ames test for mutagenicity and LC-MS chemical analysis of the exudate. An open label cluster-randomised clinical trial was performed, enrolling participants from three different clusters with skin lesions less than 1 cm in diameter. Each cluster comprising 50 participants was randomly assigned to one of three treatment arms namely topical exudate, topical Savlon antiseptic cream, and standard care (soap and water treatment), all administered daily for 2 days. The primary outcome was clinical healing/improvement measured at days 7 and 14, assessed by three dermatologists using blinded photographs. The primary analysis was assessed as non-inferiority of F. septica treatment based on the risk difference for healing/improvement. RESULTS: In vitro, the exudate which is rich in the alkaloid ficuseptine, was found to be non-mutagenic whilst also inhibiting pro-inflammatory responses and exhibiting antibacterial activity. When administered to participants enrolled in the clinical trial, no significant differences were observed between the healing efficacy of F. septica exudate and the two comparator treatments (Savlon antiseptic cream and soap/water treatment). At day 14, but not at day 7, the efficacy of F. septica exudate for healing/improving the ulcers was non-inferior to Savlon antiseptic cream or water/soap treatment. CONCLUSIONS: F. septica exudate is non-mutagenic and has both bactericidal and anti-inflammatory properties. When applied topically to small cutaneous ulcers, the exudate has a healing effect that is non-inferior to Savlon antiseptic cream and standard treatment with soap and water at day 14. Our findings, which should be confirmed in larger clinical trials, have important public health implications.

Characterization of oxidative stress status during diabetic bone healing.

Early events associated with bone healing in patients with type 2 diabetes mellitus appear to be delayed. Hyperglycaemia and an associated increase in oxidative stress are cited as potential factors leading to a change in cellular behaviour. Using an in vivo model monitoring bone formation around implants placed into rat mandibles, we have previously identified that the onset of cell proliferation and osteoblast differentiation are delayed and subsequently prolonged compared with normal bone. This study used the same implant model to characterize oxidative stress biomarkers and primary antioxidant enzyme profiles during diabetic bone healing in vivo. Implants were placed into the sockets of incisors extracted from the mandibles of normal Wistar and diabetic Goto-Kakizaki rats for 3 and 9 weeks after implant insertion. Histochemical analysis confirmed a delay in bone healing around implants in diabetic animals. Immunohistochemical localization of peri-cellular staining for protein carbonyl groups, as a biomarker of oxidized protein content, was slightly higher in diabetic granulation tissue compared with normal tissue. However, no differences were observed in the staining patterns of advanced glycation end products. Minimal differences were observed in the number of cells positive for cytoplasmic superoxide dismutase (SOD)1 or mitochondrial SOD2. Significantly, catalase was absent in diabetic tissues. The results suggest that the oxidative environment in healing bone is differentially affected by hyperglycaemia, particularly in relation to catalase. The significance of these observations for diabetic bone healing is discussed.

Modification of gingival proteoglycans by reactive oxygen species: potential mechanism of proteoglycan degradation during periodontal diseases.

Reactive oxygen species (ROS) overproduction and oxidative stress are increasingly being implicated in the extracellular matrix (ECM) degradation associated with chronic inflammatory conditions, such as periodontal diseases. The present study investigated the effects of ROS exposure on the proteoglycans of gingival tissues, utilizing an in vitro model system comprised of supra-physiological oxidant concentrations, to ascertain whether gingival proteoglycan modification and degradation by ROS contributed to the underlying mechanisms of ECM destruction during active gingivitis. Proteoglycans were purified from ovine gingival tissues and exposed to increasing H2O2 concentrations or a hydroxyl radical (·OH) flux for 1 h or 24 h, and ROS effects on proteoglycan core proteins and sulfated glycosaminoglycan (GAG) chains were assessed. ROS were capable of degrading gingival proteoglycans, with ·OH species inducing greater degradative effects than H2O2 alone. Degradative effects were particularly manifested as amino acid modification, core protein cleavage, and GAG chain depolymerization. Proteoglycan core proteins were more susceptible to degradation than GAG chains with H2O2 alone, although core proteins and GAG chains were both extensively degraded by ·OH species. Proteoglycan exposure to ·OH species for 24 h induced significant core protein amino acid modification, with decreases in glutamate, proline, isoleucine, and leucine; and concomitant increases in serine, glycine, and alanine residues. As clinical reports have previously highlighted proteoglycan core protein degradation during chronic gingivitis, whereas their sulfated GAG chains remain relatively intact, these findings potentially provide further evidence to implicate ROS in the pathogenesis of active gingivitis, complementing the enzymic mechanisms of periodontal tissue destruction already established.

Synergistic In Vitro Antimicrobial Activity of Pomegranate Rind Extract and Zinc (II) against Micrococcus luteus under Planktonic and Biofilm Conditions.

Infectious diseases caused by microbial biofilms are a major clinical problem, and new antimicrobial agents that can inhibit biofilm formation and eradicate pre-formed biofilms are urgently needed. Pomegranate extracts are a well-established folkloric medicine and have been used in the treatment of infectious diseases since ancient times, whilst the addition of metal ions, including zinc (II), has enhanced the antimicrobial activity of pomegranate. Micrococcus luteus is generally a non-pathogenic skin commensal bacterium, although it can act as an opportunistic pathogen and cause serious infections, particularly involving catheterization and comorbidities. The aims of this study were to evaluate the holistic activity of pomegranate rind extract (PRE), Zn (II), and PRE/Zn (II) individually and in combination against M. luteus under both planktonic and biofilm conditions. Antimicrobial activity was detected in vitro using the broth dilution method, and synergistic activity was determined using checkerboard and time-kill assays. Effects on biofilm formation and eradication were determined by crystal violet and BacLightTM Live/Dead staining. PRE and Zn (II) exerted antimicrobial activity against M. luteus under both planktonic and biofilm conditions. After 4 h, potent synergistic bactericidal activity was also found when PRE and Zn (II) were co-administered under planktonic conditions (log reductions: PRE 1.83 ± 0.24, Zn (II) 3.4 ± 0.08, and PRE/Zn (II) 6.88 ± 1.02; p < 0.0001). In addition, greater heterogeneity was induced in the structure of M. luteus biofilm using the PRE/Zn (II) combination compared to when PRE and Zn (II) were applied individually. The activity of PRE and the PRE/Zn (II) combination could offer a novel antimicrobial therapy for the treatment of disease-associated infections caused by M. luteus and potentially other bacteria.

Differential SOD2 and GSTZ1 profiles contribute to contrasting dental pulp stem cell susceptibilities to oxidative damage and premature senescence.

BACKGROUND: Dental pulp stem cells (DPSCs) are increasingly being advocated as viable cell sources for regenerative medicine-based therapies. However, significant heterogeneity in DPSC expansion and multi-potency capabilities are well-established, attributed to contrasting telomere profiles and susceptibilities to replicative senescence. As DPSCs possess negligible human telomerase (hTERT) expression, we examined whether intrinsic differences in the susceptibilities of DPSC sub-populations to oxidative stress-induced biomolecular damage and premature senescence further contributed to this heterogeneity, via differential enzymic antioxidant capabilities between DPSCs. METHODS: DPSCs were isolated from human third molars by differential fibronectin adhesion, and positive mesenchymal (CD73/CD90/CD105) and negative hematopoietic (CD45) stem cell marker expression confirmed. Isolated sub-populations were expanded in H2O2 (0-200 µM) and established as high or low proliferative DPSCs, based on population doublings (PDs) and senescence (telomere lengths, SA-ß-galactosidase, p53/p16INK4a/p21waf1/hTERT) marker detection. The impact of DPSC expansion on mesenchymal, embryonic, and neural crest marker expression was assessed, as were the susceptibilities of high and low proliferative DPSCs to oxidative DNA and protein damage by immunocytochemistry. Expression profiles for superoxide dismutases (SODs), catalase, and glutathione-related antioxidants were further compared between DPSC sub-populations by qRT-PCR, Western blotting and activity assays. RESULTS: High proliferative DPSCs underwent > 80PDs in culture and resisted H2O2-induced senescence (50-76PDs). In contrast, low proliferative sub-populations exhibited accelerated senescence (4-32PDs), even in untreated controls (11-34PDs). While telomere lengths were largely unaffected, certain stem cell marker expression declined with H2O2 treatment and expansion. Elevated senescence susceptibilities in low proliferative DPSC (2-10PDs) were accompanied by increased oxidative damage, absent in high proliferative DPSCs until 45-60PDs. Increased SOD2/glutathione S-transferase ζ1 (GSTZ1) expression and SOD activities were identified in high proliferative DPSCs (10-25PDs), which declined during expansion. Low proliferative DPSCs (2-10PDs) exhibited inferior SOD, catalase and glutathione-related antioxidant expression/activities. CONCLUSIONS: Significant variations exist in the susceptibilities of DPSC sub-populations to oxidative damage and premature senescence, contributed to by differential SOD2 and GSTZ1 profiles which maintain senescence-resistance/stemness properties in high proliferative DPSCs. Identification of superior antioxidant properties in high proliferative DPSCs enhances our understanding of DPSC biology and senescence, which may be exploited for selective sub-population screening/isolation from dental pulp tissues for regenerative medicine-based applications.

Myofibroblasts: Function, Formation, and Scope of Molecular Therapies for Skin Fibrosis.

Myofibroblasts are contractile, α-smooth muscle actin-positive cells with multiple roles in pathophysiological processes. Myofibroblasts mediate wound contractions, but their persistent presence in tissues is central to driving fibrosis, making them attractive cell targets for the development of therapeutic treatments. However, due to shared cellular markers with several other phenotypes, the specific targeting of myofibroblasts has long presented a scientific and clinical challenge. In recent years, myofibroblasts have drawn much attention among scientific research communities from multiple disciplines and specialisations. As further research uncovers the characterisations of myofibroblast formation, function, and regulation, the realisation of novel interventional routes for myofibroblasts within pathologies has emerged. The research community is approaching the means to finally target these cells, to prevent fibrosis, accelerate scarless wound healing, and attenuate associated disease-processes in clinical settings. This comprehensive review article describes the myofibroblast cell phenotype, their origins, and their diverse physiological and pathological functionality. Special attention has been given to mechanisms and molecular pathways governing myofibroblast differentiation, and updates in molecular interventions.

A Time-Kill Assay Study on the Synergistic Bactericidal Activity of Pomegranate Rind Extract and Zn (II) against Methicillin-Resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa.

There is a need for new antimicrobial systems due to increased global resistance to current antimicrobials. Pomegranate rind extract (PRE) and Zn (II) ions both possess a level of antimicrobial activity and work has previously shown that PRE/Zn (II) in combination possesses synergistic activity against Herpes simplex virus and Micrococcus luteus. Here, we determined whether such synergistic activity extended to other, more pathogenic, bacteria. Reference strains of methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa were cultured and subjected to challenge by PRE, Zn (II), or PRE + Zn (II), in time-kill assays. Data were obtained independently by two researchers using different PRE preparations. Statistically significant synergistic activity for PRE + Zn (II) was shown for all four bacterial strains tested compared to untreated controls, although the extent of efficacy and timescales varied. Zn (II) exerted activity and at 1 h, it was not possible to distinguish with PRE + Zn (II) combination treatment in all cases. PRE alone showed low activity against all four bacteria. Reproducible synergistic bactericidal activity involving PRE and Zn (II) has been confirmed. Potential mechanisms are discussed. The development of a therapeutic system that possesses demonstrable antimicrobial activity is supported which lends itself particularly to topical delivery applications, for example MRSA infections.

A New Look at the Purported Health Benefits of Commercial and Natural Clays.

Clays attributed to have medicinal properties have been used since prehistoric times and are still used today as complementary medicines, which has given rise to unregulated "bioceutical" clays to treat skin conditions. Recently, clays with antibacterial characteristics have been proposed as alternatives to antibiotics, potentially overcoming modern day antibiotic resistance. Clays with suggested antibacterial properties were examined to establish their effects on common wound-infecting bacteria. Geochemical, microscopical, and toxicological characterization of clay particulates, their suspensions and filtered leachates was performed on THP-1 and HaCaT cell lines. Cytoskeletal toxicity, cell proliferation/viability (MTT assays), and migration (scratch wounds) were further evaluated. Clays were assayed for antibacterial efficacy using minimum inhibitory concentration assays. All clays possessed a mineral content with antibacterial potential; however, clay leachates contained insufficient ions to have any antibacterial effects. All clay leachates displayed toxicity towards THP-1 monocytes, while clay suspensions showed less toxicity, suggesting immunogenicity. Reduced clay cytotoxicity on HaCaTs was shown, as many leachates stimulated wound-healing responses. The "Green" clay exhibited antibacterial effects and only in suspension, which was lost upon neutralization. pH and its interaction with clay particle surface charge is more significant than previously understood to emphasize dangers of unregulated marketing and unsubstantiated bioceutical claims.