Grape seed extract suppresses lipopolysaccharide-induced matrix metalloproteinase (MMP) secretion by macrophages and inhibits human MMP-1 and -9 activities

Prodelphinidins enhance dentin matrix properties and promote adhesion to methacrylate resin

OBJECTIVE

Investigate the bioactivity and stability of Rhodiola rosea (RR) fractions as a natural source of prodelphinidin gallate (PDg) on dentin collagen via analysis of the viscoelastic and resin-dentin adhesive properties of the dentin matrix.

METHODS

The biomimicry and stability of RR subfractions (F1, F2, F3 and F4) with collagen were determined by dynamic mechanical analysis (DMA). DMA used a strain sweep method to assess the dentin matrix viscoelastic properties [storage (E'), loss (E"), and complex (E*) moduli and tan δ] after treatment, 7-, 30- and 90-days of storage in simulated body fluids (SBF). Resin-dentin interface properties were assessed after 1 and 90-days in SBF by microtensile bond strength test and confocal laser scanning microscopy. Data were analyzed using two and one-way ANOVA and post-hoc tests (α = 0.05).

RESULTS

RR fractions increased dentin matrix complex (96 - 69 MPa) and storage (95 - 68 MPa) moduli, compared to the control (∼9 MPa) in the ranking order: F2 ≥ F3 = F1 = F4 > control (p < 0.001). Treatment did not affect tan δ values. After 30- and 90-days, RR-treated dentin E*, E' and tan δ decreased (p < 0.001). F2 fraction yielded the highest microtensile bond strength (43.9 MPa), compared to F1, F4 (35.9 - 31.7 MPa), and control (29 MPa). RR-treated interfaces mediated stable surface modifications and enhanced collagen-methacrylate resin interactions at the bioadhesive interface.

SIGNIFICANCE

Prodelphinidin gallates from RR are potent and reasonably stable biomimetic agents to dentin. Higher potency of F2 fraction with the dentin matrix and the adhesive interface is associated with a degree of polymerization of 2-3 and gallo(yl) motifs.

Anticaries properties of natural berries: systematic literature review

CONTEXT

Anticariogenic properties have been ascribed to polyphenolic compounds present in high concentrations in numerous fruits. Berries, in particular, have been reported as potentially having an inhibitory effect on the dental biofilm and subsequently on caries, but the evidence is unclear.

OBJECTIVE

The objective of this review was to explore the literature and summarize the evidence for berries having an inhibitory effect on the dental biofilm and an anticariogenic effect.

DATA SOURCES

Following Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, the PubMed, Web of Science, and SCOPUS databases were scanned using predefined and accessible terms, with a search strategy based on a structured PICO question.

DATA EXTRACTION

After article selection, 23 studies met the inclusion criteria, most of them being in vitro studies. A risk assessment was performed, and data were extracted and presented in a table for qualitative analysis.

DATA ANALYSIS

Meta-analyses were conducted using standardized mean differences (SMDs) with a 95% confidence interval (CI) by Review manager 5.4.

RESULTS

Only 3 types of berries were found to have a reported anticaries effect: grape seed extract (GSE), cranberry, and sour cherry. Nine studies that fulfilled the eligibility criteria were subjected to quantitative analysis. Meta-analyses showed GSE was associated with enhanced remineralization of dental enamel (SMD = .96 95% CI [.45, 1.46], P < .0002) and of dentin (SMD = .65 95% CI [.13, 1.17], P = .01). Cranberry extracts positively influenced the cariogenic dental biofilm by decreasing the biofilm biomass (SMD = -2.23 95% CI [-4.40, -.05], P = .04), and biovolume (SMD = -2.86 95% CI [-4.34, -1.37], P = .0002), and increasing the biofilm pH (SMD = 7.9 95% CI [3.49, 12.31], P < .0004).

CONCLUSION

Within the limitations of this systematic review and metaanalysis, GSE and cranberries or their active compounds could represent an alternative for caries management. Further clinical trials are needed to verify this effect in a clinical setting.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020223579.

An Up-Scalable and Cost-Effective Methodology for Isolating a Polypeptide Matrix Metalloproteinase-9 Inhibitor from Lupinus albus Seeds

One of the most challenging problems with food-borne bioactive compounds is that there are commonly no cost-effective, generally recognized as safe (GRAS) methods for obtaining gram quantities of their purified forms. Here we aimed at developing a method to isolate deflamin, an oligomeric protein from lupin seeds with anti-inflammatory and anticancer activity through matrix metalloprotease (MMP)-9 inhibition. Our goal was to develop a GRAS method that could be easily up-scalable whilst maintaining deflamin’s activity. A sequential precipitation methodology was developed, using an aqueous extraction, followed by heat denaturation, acid precipitation and solubilization in ethanol. A final precipitation with 90% ethanol yielded a purified protein which was sequenced through mass spectrometry and tested for its MMP inhibitory activity using the Dye-quenched (DQ) gelatin assay and the standard wound healing assay in HT29 cells. The developed method yielded a purified oligomer, which represented 0.1% (w/w) of total dry seed weight and was positively confirmed to be deflamin. It further showed to effectively reduce MMP-9 gelatinolytic activity as well as colon cancer cell migration, hence corroborating the effectiveness of our method. Overall, this is the first reported method for isolating an MMP-9 inhibitor from legume seeds, which is up-scalable to an industrial level, in a cost-effective manner.

Computational and In Vitro Investigation of (-)-Epicatechin and Proanthocyanidin B2 as Inhibitors of Human Matrix Metalloproteinase 1

Matrix metalloproteinases 1 (MMP-1) energetically triggers the enzymatic proteolysis of extracellular matrix collagenase (ECM), resulting in progressive skin aging. Natural flavonoids are well known for their antioxidant properties and have been evaluated for inhibition of matrix metalloproteins in human. Recently, (-)-epicatechin and proanthocyanidin B2 were reported as essential flavanols from various natural reservoirs as potential anti-inflammatory and free radical scavengers. However, their molecular interactions and inhibitory potential against MMP-1 are not yet well studied. In this study, sequential absorption, distribution, metabolism, and excretion (ADME) profiling, quantum mechanics calculations, and molecular docking simulations by extra precision Glide protocol predicted the drug-likeness of (-)-epicatechin (−7.862 kcal/mol) and proanthocyanidin B2 (−8.145 kcal/mol) with the least reactivity and substantial binding affinity in the catalytic pocket of human MMP-1 by comparison to reference bioactive compound epigallocatechin gallate (−6.488 kcal/mol). These flavanols in docked complexes with MMP-1 were further studied by 500 ns molecular dynamics simulations that revealed substantial stability and intermolecular interactions, viz. hydrogen and ionic interactions, with essential residues, i.e., His218, Glu219, His222, and His228, in the active pocket of MMP-1. In addition, binding free energy calculations using the Molecular Mechanics Generalized Born Surface Area (MM/GBSA) method suggested the significant role of Coulomb interactions and van der Waals forces in the stability of respective docked MMP-1-flavonol complexes by comparison to MMP-1-epigallocatechin gallate; these observations were further supported by MMP-1 inhibition assay using zymography. Altogether with computational and MMP-1–zymography results, our findings support (-)-epicatechin as a comparatively strong inhibitor of human MMP-1 with considerable drug-likeness against proanthocyanidin B2 in reference to epigallocatechin gallate.

Research Advances in the Use of Bioactive Compounds from Vitis vinifera By-Products in Oral Care

Oral health is considered an important factor of general health and it contributes to the quality of life. Despite the raising awareness of preventive measures, the prevalence of oral health conditions continues to increase. In this context, a growing interest in investigating natural resources like Vitis vinifera (V. vinifera) phenolic compounds (PhCs) as oral health promoters has emerged. This paper aims to review the evidence about the bioactivities of V. vinifera by-products in oral health. Up to date, a high number of studies have thoroughly reported the antimicrobial and antiplaque activity of V. vinifera extracts against S. mutans or in multi-species biofilms. Moreover, the bioactive compounds from V. vinifera by-products have been shown to modulate the periodontal inflammatory response and the underlying oxidative stress imbalance induced by the pathogenic bacteria. Considering these beneficial effects, the utility of V. vinifera by-products in the maintaining of oral health and the necessary steps towards the development of oral care products were emphasized. In conclusion, the high potential of V. vinifera by-products could be valorized in the development of oral hygiene products with multi-target actions in the prevention and progression of several oral conditions.

Dietary Grape Pomace Supplementation in Dairy Cows: Effect on Nutritional Quality of Milk and Its Derived Dairy Products

Grape pomace (GP) is the main solid by-product of winemaking and represents a rich source of potent bioactive compounds which could display a wide range of beneficial effects in human health for their association with reduced risk of several chronic diseases. Several studies have proposed the use of GP as a macro-ingredient to obtain economically worthwhile animal feedstuffs naturally enriched by polyphenols and dietary fibers. Moreover, the research carried out in this field in the last two decades evidences the ability of GP to induce beneficial effects in cow milk and its derived dairy products. First of all, a general increase in concentration of polyunsaturated fatty acids (PUFA) was observed, and this could be considered the reflection of the high content of these compounds in the by-product. Furthermore, an improvement in the oxidative stability of dairy products was observed, presumably as a direct consequence of the high content of bioactive compounds in GP that are credited with high and well-characterized antioxidant functions. Last but not least, particularly in ripened cheeses, volatile compounds (VOCs) were identified, arising both from lipolytic and proteolytic processes and commonly associated with pleasant aromatic notes. In conclusion, the GP introduction in the diet of lactating cows made it possible to obtain dairy products characterized by improved nutritional properties and high health functionality. Furthermore, the presumable improvement of organoleptic properties seems to be effective in contributing to an increase in the consumer acceptability of the novel products. This review aims to evaluate the effect of the dietary GP supplementation on the quality of milk and dairy products deriving from lactating dairy cows.

Evidence to the role of interflavan linkages and galloylation of proanthocyanidins at sustaining long-term dentin biomodification

OBJECTIVES

The interactivity of proanthocyanidins (PACs) with collagen modulates dentin matrix biomechanics and biostability. Herein, PAC extracts selected based on structural diversity were investigated to determine key PAC features driving sustained effects on dentin matrices over a period of 18months.

METHODS

The chemical profiles of PAC-rich plant sources, Pinus massoniana (PM), Cinnamomum verum (CV) and Hamamelis virginiana (HV) barks, as well as Vitis vinifera (VV) seeds, were obtained by diol HPLC analysis after partitioning of the extracts between methyl acetate and water. Dentin matrices (n=15) were prepared from human molars to determine the apparent modulus of elasticity over 18months of aging. Susceptibility of the dentin matrix to degradation by endogenous and exogenous proteases was determined by presence of solubilized collagen in supernatant, and resistance to degradation by bacterial collagenase, respectively. Data were analyzed using ANOVA and Games-Howell post hoc tests (α=0.05).

RESULTS

After 18months, dentin matrices modified by PM and CV extracts, containing only non-galloylated PACs, were highly stable mechanically (p<0.05). Dentin matrices treated with CV exhibited the lowest degradation by bacterial collagenase after 1h and 18months of aging (p<0.05), while dentin matrices treated with PM showed the least mass loss and collagen solubilization by endogenous enzymes over time (p<0.05).

SIGNIFICANCE

Resistance against long-term degradation was observed for all experimental groups; however, the most potent and long-lasting dentin biomodification resulted from non-galloylated PACs.

Morphometric and histopathological evaluation of the effect of grape seed proanthocyanidin on alveolar bone loss in experimental diabetes and periodontitis

OBJECTIVE

Grape seed proanthocyanidine extract (GSPE) is a strong antioxidant derived from the grape seeds (Vitis vinifera, Terral J.F.) and has a polyphenolic structure with a wide range of biological activity. The aim of the present study was to evaluate the effects of GSPE on alveolar bone loss and histopathological changes in rats with diabetes mellitus and ligature-induced periodontitis.

MATERIAL AND METHODS

Forty rats were divided into 6 study groups. Control (C, 6 rats) group, periodontitis (P, 6 rats) group, diabetes (D, 6 rats) group, diabetes and periodontitis (D+P, 6 rats) group, diabetes, periodontitis and 100 mg/kg/day GSPE (GSPE-100, 8 rats), and diabetes, periodontitis and 200 mg/kg/day GSPE (GSPE-200, 8 rats) group. Diabetes mellitus was induced by intraperitoneal injection of a single dose of streptozotocin (60 mg/kg). Periodontitis was induced via ligation method. Silk ligatures were placed at the mandibular right first molars. GSPE was administered by oral gavage. After 30 days, all rats were killed. Alveolar bone loss was measured morphometrically via a stereomicroscope. For histopathological analyses, Alizarin red staining, and matrix metalloproteinase (MMP)-8, vascular endothelial growth factor and hypoxia inducible factor (HIF)-1α immunohistochemistry were performed. Tartrate-resistant acid phosphatase-positive osteoclast cells and relative total inflammatory cells were also determined.

RESULTS

The highest alveolar bone loss was observed in the D+P group (P < .05). GSP-200 group decreased alveolar bone loss (P < .05). The D+P group had the highest osteoclast counts, but the difference was not significant compared to the P, GSPE-100 and GSPE-200 groups (P > .05). The inflammation in the D+P group was also higher than the other groups (P < .05). The osteoblast numbers increased in the GSPE-100 and GSPE-200 groups compared to the P and D+P groups (P < .05). MMP-8 and HIF-1α levels were highest in the D+P group and GSPE significantly decreased these levels (P < .05).

CONCLUSION

Within the limits of this animal study, it can be suggested that GSPE administration may decrease periodontal inflammation and alveolar bone loss via decreasing MMP-8 and HIF-1α levels and increase osteoblastic activity in diabetic rats with experimental periodontitis.

Role of MicroRNA Regulation in Obesity-Associated Breast Cancer: Nutritional Perspectives

Breast cancer is the most common malignancy diagnosed in women, and the incidence of breast cancer is increasing every year. Obesity has been identified as one of the major risk factors for breast cancer progression. The mechanisms by which obesity contributes to breast cancer development is not yet understood; however, there are a few mechanisms counted as potential producers of breast cancer in obesity, including insulin resistance, chronic inflammation and inflammatory cytokines, adipokines, and sex hormones. Recent emerging evidence suggests that alterations in microRNA (miRNA) expressions are found in several diseases, including breast cancer and obesity; however, miRNA roles in obesity-linked breast cancer are beginning to unravel. miRNAs are thought to be potential noninvasive biomarkers for diagnosis and prognosis of cancer patients with comorbid conditions of obesity as well as therapeutic targets. Recent studies have evidenced that nutrients and other dietary factors protect against cancer and obesity through modulation of miRNA expressions. Herein, we summarize a comprehensive overview of up-to-date information related to miRNAs and their molecular targets involved in obesity-associated breast cancer. We also address the mechanisms by which dietary factors modulate miRNA expression and its protective roles in obesity-associated breast cancer. It is hoped that this review would provide new therapeutic strategies for the treatment of obesity-associated breast cancer to reduce the burden of breast cancer.

Protective effects of grape stem extract against UVB-induced damage in C57BL mice skin

Humans have become exposed to another form of a trait which is ultraviolet B (UVB) radiation reaching the earth's surface. This has become a major source of oxidative stress that ultimately leads to inflammation, DNA damage, photoaging and pigmentation disorders etc. Although several studies have shown the photo-protective role of different grape parts like the fruits and seeds, little or no data demonstrating the in vivo photo-protective role of grape stem, which is the most discarded part of the grape are available. We evaluated the protective influence of grape stem extract against UVB-induced oxidative damage in C57BL mice characterized by epidermal hyperplasia, pigmentation, collagen degradation and inflammation. Grape stem extract was administered topically 1week before UVB irradiation (120mJ/cm²) and continued until the termination of the experiment. A group of non-irradiated mice and a group of irradiated mice topically administered with propylene were used as a negative and positive control. Epidermal thickness, pigmentation, erythema, mast cell and neutrophil infiltration, collagen degradation and COX-2, Nrf2, and HO-1 expressions were evaluated. Grape stem extract markedly recovered skin damage induced by the UVB radiation through the prevention of epidermal hyperplasia, pigmentation, erythema, mast cell and neutrophil infiltrations, collagen degradation and COX-2, Nrf2, and HO-1 expressions. Our study demonstrated for the first time in C57BL mice that grape stem extract reduces UVB-induced oxidative damage and hence can play a protective role in skin photo-damage.

Effects of grape seed extract on periodontal disease: an experimental study in rats

Objective

This study aimed to demonstrate the effect of grape seed extract (GSE) on periodontitis.

Material and Methods

Ligature induced periodontitis was created in 40 rats and they were assigned to four equal groups. One group was fed laboratory diet (group A) while three groups received GSE additionally. Silk ligatures were placed around the cervical area of the mandibular first molars for four weeks to induce periodontitis. The GSE groups were reallocated regarding GSE consumption as: for two weeks before ligation (group B; totally eight weeks), from ligation to two weeks after removal of the ligature (group C; totally six weeks), and for two weeks from ligature removal (group D; totally two weeks). Sections were assessed histologically and immunohistochemically. Inflammatory cell number (ICN), connective tissue attachment level (CAL), osteoclast density (OD), IL-10 and TGF-β stainings in gingival epithelium (GE), connective tissue (GC), and periodontal ligament (PL) were used as the study parameters.

Results

Lower ICN, higher CAL, and lower OD were observed in the GSE groups (p<0.05). IL-10 was more intensive in the GSE groups and in the GEs (p<0.05). Group B showed the highest IL-10 for PL (p<0.05). TGF-ß was higher in the GEs of all groups (p<0.017).

Conclusions

The results suggest anti-inflammatory activities of GSE, but further investigations are needed for clarification of these activities.

Redução da atividade proteolítica da dentina após curtos períodos de aplicação de proantocianidina

ResumoIntroduçãoAgentes promotores de ligações cruzadas têm sido investigados como inibidores da atividade enzimática da dentina, o que favoreceria a longevidade das restaurações adesivas.ObjetivoAvaliar o efeito do tratamento da dentina com proantocianidina (PA), em curtos períodos de tempo, na inibição da atividade de MMPs in situ.Material e métodoQuarenta espécimes de dentina (1×1×6 mm) foram obtidos de molares hígidos e divididos em quatro grupos (n=10). Os espécimes foram condicionados com ácido fosfórico por 15 s, seguido de lavagem em água deionizada. A dentina condicionada foi tratada com: água, 5% PA por 5 s, 15 s ou 30 s. A atividade de MMP foi analisada colorimetricamente (SensoLyte®) e os dados de absorbância (412 nm) foram submetidos aos testes de ANOVA e Tukey (α=0,05).ResultadoTodos os períodos de tratamento foram capazes de reduzir a atividade de MMPs, sendo que os melhores resultados foram observados para a dentina tratada com PA por 15 s (63,1% redução) e 30 s (70,2%). O tratamento por 5 s foi capaz de inibir 39,9% das MMPs.ConclusãoA aplicação de PA sobre a dentina condicionada foi capaz de reduzir a atividade de MMPs mesmo em períodos de tempo extremamente curtos, como 5 s. No entanto, melhores resultados foram obtidos com os maiores períodos de tratamento.

Cancer Chemopreventive Potential of Procyanidin

Chemoprevention entails the use of synthetic agents or naturally occurring dietary phytochemicals to prevent cancer development and progression. One promising chemopreventive agent, procyanidin, is a naturally occurring polyphenol that exhibits beneficial health effects including anti-inflammatory, antiproliferative, and antitumor activities. Currently, many preclinical reports suggest procyanidin as a promising lead compound for cancer prevention and treatment. As a potential anticancer agent, procyanidin has been shown to inhibit the proliferation of various cancer cells in “in vitro and in vivo”. Procyanidin has numerous targets, many of which are components of intracellular signaling pathways, including proinflammatory mediators, regulators of cell survival and apoptosis, and angiogenic and metastatic mediators, and modulates a set of upstream kinases, transcription factors, and their regulators. Although remarkable progress characterizing the molecular mechanisms and targets underlying the anticancer properties of procyanidin has been made in the past decade, the chemopreventive targets or biomarkers of procyanidin action have not been completely elucidated. This review focuses on the apoptosis and tumor inhibitory effects of procyanidin with respect to its bioavailability.

Grape seed extracts inhibit dentin matrix degradation by MMP-3

Since Matrix metalloproteinases (MMPs) have been suggested to contribute to dentin caries progression, the hypothesis that MMP inhibition would affect the progression of dentin caries is clinically relevant. Grape seed extracts (GSE) have been previously reported to be natural inhibitors of MMPs.

OBJECTIVE

To evaluate the capacity of a GSE mouthrinse to prevent the degradation of demineralized dentin matrix by MMP-3 (stromelysin-1).

MATERIALS AND METHODS

Standardized blocks of dentin obtained from sound permanent teeth extracted for orthodontic reasons were demineralized with Ethylenediaminetetraacetic acid (EDTA) and pretreated either with (A) GSE (0.2% w/v), (B) amine fluoride (AmF) (20% w/v), (C) a mouthrinse which contains both, (D) placebo, (E) sodium fluoride (0.15 mg.ml(-1)), (F) PBS, (G) Chlorhexidine digluconate (CHX), or (H) zinc chloride (ZnCl2). The dentin blocks were then incubated with activated recombinant MMP-3. The supernatants were analyzed by Western Blot for several dentin matrix proteins known to be MMP-3 substrate. In parallel, scanning electron microscopy (SEM) was performed on resin replica of the dentin blocks.

RESULTS

Western blot analysis of the supernatants revealed that MMP-3 released from the dentin matrix small proteoglycans (decorin and biglycan) and dentin sialoprotein (DSP) in the AmF, sodium fluoride, PBS and placebo pretreated groups, but not in the GSE and mouthrinse pretreated groups. SEM examination of resin replica showed that the mouthrinse and its active components not only had an anti-MMP action but also modified the dentin surface accessibility.

CONCLUSION

This study shows that GSE either alone or combined with AmF as in the evaluated mouthrinse limits dentin matrix degradation. This association may be promising to prevent the progression of caries within dentin. However, the procedure should be adapted to clinically relevant durations.

Anti-proteolytic capacity and bonding durability of proanthocyanidin-biomodified demineralized dentin matrix

Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin (PA) for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin-dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.

Characterization of azoxymethane-induced colon tumor metastasis to lung in a mouse model relevant to human sporadic colorectal cancer and evaluation of grape seed extract efficacy

The second leading cause of cancer-related deaths (both genders combined) in the United States is colorectal cancer (CRC). This emphasizes the need to develop both effective therapies for CRC patients and pre-clinical models mimicking human disease that carry translational potential in drug-development. Notably, at present there are no in situ models of CRC metastasis to lung. In our azoxymethane-induced colon tumorigenesis study in A/J mice assessing grape seed extract (GSE) efficacy, during necropsy we also found multiple lung nodules suggestive of colon tumor metastasis to lung that were significantly inhibited in GSE fed group. Both histopathological and molecular studies were performed to characterize and establish the origin of these lesions in lung. Histologically these nodules were determined as adenocarcinoma of mucin origin. Molecular analyses by immunohistochemistry (IHC) and RT-PCR revealed strong protein and transcript levels of colon specific markers CDX2 and CK20 in these lung nodules compared to uninvolved control lung tissue. Vis-à-vis, these nodules also showed minimally expressed lung specific biomarkers, specifically surfactant D and TTF-1, in IHC analysis. Additionally, 0.25% GSE supplementation in diet (w/w) decreased the incidence of these lung nodules by 53% and their total number by 66%. Together, the characterization of this unique in situ mouse model of CRC metastasis to lung provides translational opportunities in developing effective therapies to clinically manage and treat CRC at the advanced stage. Moreover, GSE efficacy in inhibiting CRC metastasis to lung in this model further supports its translational potential in controlling CRC growth, progression and metastasis in patients.

Dentin matrix degradation by host matrix metalloproteinases: inhibition and clinical perspectives toward regeneration

Bacterial enzymes have long been considered solely accountable for the degradation of the dentin matrix during the carious process. However, the emerging literature suggests that host-derived enzymes, and in particular the matrix metalloproteinases (MMPs) contained in dentin and saliva can play a major role in this process by their ability to degrade the dentin matrix from within. These findings are important since they open new therapeutic options for caries prevention and treatment. The possibility of using MMP inhibitors to interfere with dentin caries progression is discussed. Furthermore, the potential release of bioactive peptides by the enzymatic cleavage of dentin matrix proteins by MMPs during the carious process is discussed. These peptides, once identified, may constitute promising therapeutical tools for tooth and bone regeneration.

Characterization of riboflavin-modified dentin collagen matrix

Crosslinking is considered a possible approach to increasing the mechanical and structural stability and biodegradation resistance of the dentin collagen matrix. The aim of this study was to investigate the mechanical and chemical variations and collagen degradation resistance associated with crosslinking of the dentin collagen matrix with UVA-activated riboflavin. Dentin collagen matrix specimens were treated with 0.1 and 1% riboflavin for 2 min and photo-activated with 7 mW/cm(2) UVA (368 nm) for 2 min. The structural change of the dentin collagen network with collagenase exposure was investigated by AFM and SEM at different time-points. The variations in surface/bulk mechanical properties and biodegradation resistance were characterized by nano-indentation, conventional mechanical testing, and hydroxyproline liberation at different time-points. Chemical changes associated with riboflavin/collagen-matrix interaction were analyzed by micro-Raman spectroscopy. UVA-activated riboflavin increased the mechanical properties, mechanical stability, and biodegradation resistance of the dentin collagen matrix. Higher collagen-network structural resistance against collagenolytic challenges was found with crosslinking. micro-Raman spectroscopy showed a strong dependency, in both intensity and wave-number, of certain Raman bands (1242-1667 cm(-1)) with crosslinking indicating the collagen/riboflavin interactions. UVA-activated riboflavin (1%) more efficiently crosslinked the dentin collagen matrix within a relatively clinically acceptable time-frame compared with 0.1% riboflavin.

Grape-seed procyanidins inhibit the in vitro growth and invasion of pancreatic carcinoma cells

OBJECTIVES

Grape-seed procyanidins (GSPs) can inhibit cell proliferation and invasiveness in various human cancers. However, the effect of GSP on pancreatic carcinoma cells has not been investigated.

METHODS

Pancreatic carcinoma cell lines MIA PaCa-2 and BxPC-3 treated with GSP were assessed for viability by trypan blue exclusion, for cell cycle distribution by flow cytometry, for increased apoptosis by annexin V labeling, for their adhesion and invasion potential by evaluating their ability to penetrate through a matrix gel-coated Boyden chamber, and for changes in the levels of proteins involved in cellular events by immunoblotting.

RESULTS

Grape-seed procyanidin inhibited MIA PaCa-2 and BxPC-3 proliferation in a dose-dependent manner and induced G1-phase arrest of the cell cycle in BxPC-3 or mitochondria-mediated apoptosis in MIA PaCa-2. Grape-seed procyanidin also inhibited the adhesion and invasion potential of both cell lines in a dose-dependent manner, which are associated with the suppression of metalloproteases matrix metalloproteinase 9 or 2 (MMP-9 or -2) expression.

CONCLUSIONS

Grape-seed procyanidin inhibited the proliferation of pancreatic carcinoma cells by cell cycle blockage or apoptotic induction. The invasiveness was also suppressed by GSP through down-regulation of MMP-2 or MMP-9 in pancreatic carcinoma cells. Grape-seed procyanidin is a potential chemotherapeutic or preventive agent for pancreatic carcinoma.

The chemoadjuvant potential of grape seed procyanidins on p53-related cell death in oral cancer cells

BACKGROUND

To clarify the efficacy of grape seed procyanidin (GSP) on antiproliferative effects related to p53 functional status of oral squamous cell carcinoma (OSCC) for its chemoadjuvant potential.

METHODS

We used GSP to investigate SCC-25 cells with wild-type p53 gene and OEC-M1 cells with mutant p53 gene for the assessment of antiproliferative effects including cell viability, cell cycle, apoptosis, migration and invasion potential, and alterations of associated oncoproteins involved in cellular and molecular events.

RESULTS

The findings suggest that GSP on OEC-M1 cells leads to cell cycle arrest by increasing the expression of p21(Cip1) /p27(Kip1) protein without functioning mitochondria-mediated apoptosis, whereas GSP on SCC-25 cells inhibits cell proliferation via both G1-phase arrest and mitochondria-mediated apoptosis in a dose-dependent manner as a result of alterations of Bcl-2. GSP also inhibits the migration and invasion of both cells, which are associated with the suppression of matrix metalloproteinases (MMPs), MMP-2 and MMP-9.

CONCLUSION

Antiproliferative effectiveness of GSP is closely associated with the p53 status of OSCC cells. GSP displays chemoadjuvant potential via cell cycle blockage and apoptotic induction. Our findings clearly suggest that GSP may play a role as a novel chemopreventive or therapeutic agent for OSCC.

Characterization of biomodified dentin matrices for potential preventive and reparative therapies

Biomodification of existing hard tissue structures, specifically tooth dentin, is an innovative approach proposed to improve the biomechanical and biochemical properties of tissue for potential preventive or reparative therapies. The objectives of the study were to systematically characterize dentin matrices biomodified by proanthocyanidin-rich grape seed extract (GSE) and glutaraldehyde (GD). Changes to the biochemistry and biomechanical properties were assessed by several assays to investigate the degree of interaction, biodegradation rates, proteoglycan interaction, and effect of collagen fibril orientation and environmental conditions on the tensile properties. The highest degree of agent-dentin interaction was observed with GSE, which exhibited the highest denaturation temperature, regardless of the agent concentration. Biodegradation rates decreased remarkably following biomodification of dentin matrices after 24h collagenase digestion. A significant decrease in the proteoglycan content of GSE-treated samples was observed using a micro-assay for glycosaminoglycans and histological electron microscopy, while no changes were observed for GD and the control. The tensile strength properties of GD-biomodified dentin matrices were affected by dentin tubule orientation, most likely due to the orientation of the collagen fibrils. Higher and/or increased stability of the tensile properties of GD- and GSE-treated samples were observed following exposure to collagenase and 8 months water storage. Biomodification of dentin matrices using chemical agents not only affects the collagen biochemistry, but also involves interaction with proteoglycans. Tissue biomodifiers interact differently with dentin matrices and may provide the tissue with enhanced preventive and restorative/reparative abilities.

Antibacterial and anti-inflammatory activities of 4-hydroxycordoin: potential therapeutic benefits

4-Hydroxycordoin (1), a natural isopentenyloxychalcone, is a plant secondary metabolite that is relatively rare. Since there are very few reports about the biological activities of 1, its potential benefits for periodontal disease were investigated. A marked and dose-dependent antibacterial activity of 1 was observed against the three major periodontal pathogens, Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella intermedia. Moreover, compound 1 showed an antiadhesion effect, since it inhibited attachment of P. gingivalis to oral epithelial cells. Finally, using a macrophage model, the ability of 1 to inhibit the secretion of inflammatory mediators induced by Aggregatibacter actinomycetemcomitans lipopolysaccharide was demonstrated. The anti-inflammatory effect observed was associated with reduced activation of the nuclear factor-κB (NF-κB) p65 and activator protein-1 (AP-1) pathways.

Suppression of LPS-induced matrix-metalloproteinase responses in macrophages exposed to phenytoin and its metabolite, 5-(p-hydroxyphenyl-), 5-phenylhydantoin

BACKGROUND

Phenytoin (PHT) has been reported to induce gingival (gum) overgrowth (GO) in approximately 50% of patients taking this medication. While most studies have focused on the effects of PHT on the fibroblast in the pathophysiology underlying GO, few studies have investigated the potential regulatory role of macrophages in extracellular matrix (ECM) turnover and secretion of proinflammatory mediators. The aim of this study was to evaluate the effects of PHT and its metabolite, 5-(p-hydroxyphenyl-), 5-phenylhydantoin (HPPH) on LPS-elicited MMP, TIMP, TNF-α and IL-6 levels in macrophages.

METHODS

Human primary monocyte-derived macrophages (n = 6 independent donors) were pretreated with 15-50 μg/mL PHT-Na+ or 15-50 μg/mL HPPH for 1 hour. Cells were then challenged with 100 ng/ml purified LPS from the periodontal pathogen, Aggregatibacter actinomycetemcomitans. Supernatants were collected after 24 hours and levels of MMP-1, MMP-2, MMP-3, MMP-9, MMP-12, TIMP-1, TIMP-2, TIMP-3, TIMP-4, TNF-α and IL-6 determined by multiplex analysis or enzyme-linked immunoadsorbent assay.

RESULTS

A dose-dependent inhibition of MMP-1, MMP-3, MMP-9, TIMP-1 but not MMP-2 was noted in culture supernatants pretreated with PHT or HPPH prior to LPS challenge. MMP-12, TIMP-2, TIMP-3 and TIMP-2 were not detected in culture supernatants. High concentrations of PHT but not HPPH, blunted LPS-induced TNF-α production although neither significantly affected IL-6 levels.

CONCLUSION

The ability of macrophages to mediate turnover of ECM via the production of metalloproteinases is compromised not only by PHT, but its metabolite, HPPH in a dose-dependent fashion. Further, the preferential dysregulation of macrophage-derived TNF-α but not IL-6 in response to bacterial challenge may provide an inflammatory environment facilitating collagen accumulation without the counteracting production of MMPs.