scholarly journals Enterococcus faecalis exploits the human fibrinolytic system to drive excess collagenolysis: implications in gut healing and identification of druggable targets

2020 ◽  
Vol 318 (1) ◽  
pp. G1-G9 ◽  
Author(s):  
Richard A. Jacobson ◽  
Kiedo Wienholts ◽  
Ashley J. Williamson ◽  
Sara Gaines ◽  
Sanjiv Hyoju ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Healing Process ◽  
Abdominal Sepsis ◽  
Infectious Complications ◽  
Fibrinolytic System ◽  
Clinical Safety ◽  
High Concentrations ◽  
Clinically Significant

Perforations, anastomotic leak, and subsequent intra-abdominal sepsis are among the most common and feared complications of invasive interventions in the colon and remaining intestinal tract. During physiological healing, tissue protease activity is finely orchestrated to maintain the strength and integrity of the submucosa collagen layer in the wound. We (Shogan, BD et al. Sci Trans Med 7: 286ra68, 2015.) have previously demonstrated in both mice and humans that the commensal microbe Enterococcus faecalis selectively colonizes wounded colonic tissues and disrupts the healing process by amplifying collagenolytic matrix-metalloprotease activity toward excessive degradation. Here, we demonstrate for the first time, to our knowledge, a novel collagenolytic virulence mechanism by which E. faecalis is able to bind and locally activate the human fibrinolytic protease plasminogen (PLG), a protein present in high concentrations in healing colonic tissue. E. faecalis-mediated PLG activation leads to supraphysiological collagen degradation; in this study, we demonstrate this concept both in vitro and in vivo. This pathoadaptive response can be mitigated with the PLG inhibitor tranexamic acid (TXA) in a fashion that prevents clinically significant complications in validated murine models of both E. faecalis- and Pseudomonas aeruginosa-mediated colonic perforation. TXA has a proven clinical safety record and is Food and Drug Administration approved for topical application in invasive procedures, albeit for the prevention of bleeding rather than infection. As such, the novel pharmacological effect described in this study may be translatable to clinical trials for the prevention of infectious complications in colonic healing. NEW & NOTEWORTHY This paper presents a novel mechanism for virulence in a commensal gut microbe that exploits the human fibrinolytic system and its principle protease, plasminogen. This mechanism is targetable by safe and effective nonantibiotic small molecules for the prevention of infectious complications in the healing gut.

scholarly journals Collagen-Based Electrospun Materials for Tissue Engineering: A Systematic Review

2021 ◽  
Vol 8 (3) ◽  
pp. 39
Author(s):  
Britani N. Blackstone ◽  
Summer C. Gallentine ◽  
Heather M. Powell
Keyword(s):  
Systematic Review ◽  
Tissue Engineering ◽  
Collagen Type I ◽  
The Body ◽  
Pool Data ◽  
Type I ◽  
High Concentrations ◽  
Increased Strength

Collagen is a key component of the extracellular matrix (ECM) in organs and tissues throughout the body and is used for many tissue engineering applications. Electrospinning of collagen can produce scaffolds in a wide variety of shapes, fiber diameters and porosities to match that of the native ECM. This systematic review aims to pool data from available manuscripts on electrospun collagen and tissue engineering to provide insight into the connection between source material, solvent, crosslinking method and functional outcomes. D-banding was most often observed in electrospun collagen formed using collagen type I isolated from calfskin, often isolated within the laboratory, with short solution solubilization times. All physical and chemical methods of crosslinking utilized imparted resistance to degradation and increased strength. Cytotoxicity was observed at high concentrations of crosslinking agents and when abbreviated rinsing protocols were utilized. Collagen and collagen-based scaffolds were capable of forming engineered tissues in vitro and in vivo with high similarity to the native structures.

scholarly journals Development of a Topical Insulin Polymeric Nanoformulation for Skin Burn Regeneration: An Experimental Approach

2021 ◽  
Vol 22 (8) ◽  
pp. 4087
Author(s):  
Maria Quitério ◽  
Sandra Simões ◽  
Andreia Ascenso ◽  
Manuela Carvalheiro ◽  
Ana Paula Leandro ◽  
...  
Keyword(s):  
Wound Healing ◽  
Healing Process ◽  
In Vitro Release ◽  
Peptide Hormone ◽  
Plga Nanoparticles ◽  
Wound Healing Process ◽  
Target Area ◽  
Encapsulation Process

Insulin is a peptide hormone with many physiological functions, besides its use in diabetes treatment. An important role of insulin is related to the wound healing process—however, insulin itself is too sensitive to the external environment requiring the protective of a nanocarrier. Polymer-based nanoparticles can protect, deliver, and retain the protein in the target area. This study aims to produce and characterize a topical treatment for wound healing consisting of insulin-loaded poly-DL-lactide/glycolide (PLGA) nanoparticles. Insulin-loaded nanoparticles present a mean size of approximately 500 nm and neutral surface charge. Spherical shaped nanoparticles are observed by scanning electron microscopy and confirmed by atomic force microscopy. SDS-PAGE and circular dichroism analysis demonstrated that insulin preserved its integrity and secondary structure after the encapsulation process. In vitro release studies suggested a controlled release profile. Safety of the formulation was confirmed using cell lines, and cell viability was concentration and time-dependent. Preliminary safety in vivo assays also revealed promising results.

Application of the EYTEX™ System to the Evaluation of Cosmetic Products and their Ingredients

1992 ◽  
Vol 20 (1) ◽  
pp. 146-163
Author(s):  
Francis H. Kruszewski ◽  
Laura H. Hearn ◽  
Kyle T. Smith ◽  
Janice J. Teal ◽  
Virginia C. Gordon ◽  
...  
Keyword(s):  
Double Blind ◽  
Eye Irritation ◽  
Ocular Irritation ◽  
Rabbit Eye ◽  
Wide Range ◽  
High Concentrations ◽  
Alkaline Membrane ◽  
Positive Agreement

465 cosmetic product formulations and raw ingredients were evaluated with the EYTEX™ system to determine the potential of this in vitro alternative for identifying eye irritation potential. The EYTEX™ system is a non-animal, biochemical procedure developed by Ropak Laboratories, Irvine, CA, that was designed to approximate the Draize rabbit eye irritation assay for the evaluation of ocular irritation. Avon Products Inc. provided all the test samples, which included over 30 different product types and represented a wide range of eye irritancy. All the EYTEX™ protocols available at the time of this study were used. Samples were evaluated double-blind with both the membrane partition assay (MPA) and the rapid membrane assay (RMA). When appropriate, the standard assay (STD) and the alkaline membrane assay (AMA) were used, as well as specific, documented protocol modifications. EYTEX™ results were correlated with rabbit eye irritation data which was obtained from the historical records of Avon Products Inc. A positive agreement of EYTEX™ results with the in vivo assay was demonstrated by an overall concordance of 80%. The assay error was 20%, of which 18% was due to an overestimation of sample irritancy (false positives) and 2% was attributed to underestimation (false negatives). Overestimation error in this study was due in part to the inability of the protocols to accurately classify test samples with very low irritation potential. Underestimation of sample irritancy was generally associated with ethoxylated materials and high concentrations of specific types of surfactants. 100% sensitivity and 85% predictability were described by the data, indicating the efficiency of EYTEX™ in identifying known irritants. A specificity rate of 39% showed the EYTEX™ assay to be weak in discerning non-irritants. However, the EYTEX™ protocols used in this study were not designed to identify non-irritants. A compatibility rate of 99% proved the effectiveness of the EYTEX™ assay in accommodating a diversity of product types. The EYTEX™ system protocols, when used appropriately, can provide a conservative means of assessing the irritant potential of most cosmetic formulations and their ingredients.

In Vivo Testing of Sericin-Polyurethane Nanofiber Mats for Wound Healing in Rats

2017 ◽  
Vol 751 ◽  
pp. 581-585 ◽  
Author(s):  
Piyaporn Kampeerapappun ◽  
Pornpen Siridamrong
Keyword(s):  
Wound Healing ◽  
Healing Process ◽  
Active Agent ◽  
L929 Cell ◽  
Wound Healing Process ◽  
Original Size ◽  
Nanofiber Mats ◽  
Dressing Materials

The objective of this study was to investigate sericin-polyurethane nanofiber cover (SUC) for wound dressing materials in a rat skin. Sericin-polyurethane blended nanofibers were fabricated by using electrospinning. The composition of 3%w/v polyurethane in ethanol and 19% w/v sericin were blended and electrospun at 15 kV, 20 cm from tip to collector with a feed rate of 6.2 ml/hr. The mats, approximately 1.5 mm thick, were sterile by gamma irradiation with a radiation dose of 15 kGy. The samples of in vitro and in vivo testing were separated into three groups; gauze, polyurethane nanofiber cover (UC), and SUC. In vitro cultured L929 cell lines were investigated with inverted microscope. It was found that cells migrated to SCU. For in vivo tests, the remaining wound in rats was measured on day 2-14 after excision. Compared to original size of wound samples, the size of the wound remained 24% for SUC, 33% for gauze, and 34% for UC at day 8. The sericin, an active agent, contained in SUC mats was about 5 µl at 1.5 ×1.5 cm. It can be concluded that sericin is non-toxic to cells and can promote wound healing process in rats.

c-Fos-induced activation of a TATA-box-containing promoter involves direct contact with TATA-box-binding protein

1994 ◽  
Vol 14 (9) ◽  
pp. 6021-6029
Author(s):  
R Metz ◽  
A J Bannister ◽  
J A Sutherland ◽  
C Hagemeier ◽  
E C O'Rourke ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Tata Box ◽  
Binding Motif ◽  
Protein Protein Interactions ◽  
High Concentrations ◽  
Tata Box Binding Protein

Transcriptional activation in eukaryotes involves protein-protein interactions between regulatory transcription factors and components of the basal transcription machinery. Here we show that c-Fos, but not a related protein, Fra-1, can bind the TATA-box-binding protein (TBP) both in vitro and in vivo and that c-Fos can also interact with the transcription factor IID complex. High-affinity binding to TBP requires c-Fos activation modules which cooperate to activate transcription. One of these activation modules contains a TBP-binding motif (TBM) which was identified through its homology to TBP-binding viral activators. This motif is required for transcriptional activation, as well as TBP binding. Domain swap experiments indicate that a domain containing the TBM can confer TBP binding on Fra-1 both in vitro and in vivo. In vivo activation experiments indicate that a GAL4-Fos fusion can activate a promoter bearing a GAL4 site linked to a TATA box but that this activity does not occur at high concentrations of GAL4-Fos. This inhibition (squelching) of c-Fos activity is relieved by the presence of excess TBP, indicating that TBP is a direct functional target of c-Fos. Removing the TBM from c-Fos severely abrogates activation of a promoter containing a TATA box but does not affect activation of a promoter driven only by an initiator element. Collectively, these results suggest that c-Fos is able to activate via two distinct mechanisms, only one of which requires contact with TBP. Since TBP binding is not exhibited by Fra-1, TBP-mediated activation may be one characteristic that discriminates the function of Fos-related proteins.

scholarly journals Two-Step Acquisition of Resistance to the Teicoplanin-Gentamicin Combination by VanB-Type Enterococcus faecalis In Vitro and in Experimental Endocarditis

1999 ◽  
Vol 43 (3) ◽  
pp. 476-482 ◽  
Author(s):  
Agnès Lefort ◽  
Marina Baptista ◽  
Bruno Fantin ◽  
Florence Depardieu ◽  
Michel Arthur ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Acquired Resistance ◽  
Simultaneous Acquisition ◽  
Resistant Mutants

ABSTRACT The activity of vancomycin and teicoplanin combined with gentamicin was investigated in vitro against strains of Enterococcus faecalis resistant to vancomycin and susceptible to teicoplanin (VanB type) and against mutants that had acquired resistance to teicoplanin by three different mechanisms. In vitro, gentamicin selected mutants with two- to sixfold increases in the level of resistance to this antibiotic at frequencies of 10−6 to 10−7. Teicoplanin selected teicoplanin-resistant mutants at similar frequencies. Both mutations were required to abolish the activity of the gentamicin-teicoplanin combination. As expected, simultaneous acquisition of the two types of mutations was not observed. In therapy with gentamicin or teicoplanin alone, each selected mutants in three of seven rabbits with aortic endocarditis due to VanB-type E. faecalis BM4275. The vancomycin-gentamicin combination selected mutants that were resistant to gentamicin and to the combination. In contrast, the teicoplanin-gentamicin regimen prevented the emergence of mutants resistant to one or both components of the combination. These results suggest that two mutations are also required to suppress the in vivo activity of the teicoplanin-gentamicin combination.

scholarly journals Virtual Screening and Statistical Analysis in the Design of New Caffeine Analogues Molecules with Potential Epithelial Anticancer Activity

2018 ◽  
Vol 24 (5) ◽  
pp. 576-594 ◽  
Author(s):  
Josivan da Silva Costa ◽  
Karina da Silva Lopes Costa ◽  
Josiane Viana Cruz ◽  
Ryan da Silva Ramos ◽  
Luciane Barros Silva ◽  
...  
Keyword(s):  
Anticancer Activity ◽  
Binding Free Energy ◽  
Inhibitory Effect ◽  
Parametric Models ◽  
World Health ◽  
Pharmacokinetic Properties ◽  
Clinically Significant ◽  
Health Organization

About 132 thousand cases of melanoma (more severe type of skin cancer) were registered in 2014 according to the World Health Organization. This type of cancer significantly affects the quality of life of individuals. Caffeine has shown potential inhibitory effect against epithelial cancer. In this study, it was proposed to obtain new caffeine-based molecules with potential epithelial anticancer activity. For this, a training set of 21 molecules was used for pharmacophore perception procedures. Multiple linear regression analyses were used to propose mono-, bi-, tri-, and tetra-parametric models applied in the prediction of the activity. The generated pharmacophore was used to select 350 molecules available at the ZINCpharmer server, followed by reduction to 24 molecules, after selection using the Tanimoto index, yielding 10 molecules after final selection by predicted activity values > 1.5229. These ten molecules had better pharmacokinetic properties than the other ones used as reference and within the clinically significant limits. Only two molecules show minor hits of toxicity and were submitted to molecular docking procedures, showing BFE (binding free energy) values lower than the reference values. Statistical analyses indicated strong negative correlations between BFE and pharmacophoric properties (high influence on BFE lowering) and practically null correlation between BFE and BBB. The two most promising molecules can be indicated as candidates for further in vitro and in vivo analyzes.

scholarly journals Stimulation of wound healing process through ROS/RNS signals indirectly generated by N2/Ar micro-plasma - in vitro and in vivo studies

2015 ◽  
Vol 18 (2) ◽  
pp. 29-37
Author(s):  
Hien Thi Minh Ngo ◽  
Linh Quang Huynh ◽  
Liao Jiunn Der ◽  
Thuy Ngu Son Nguyen
Keyword(s):  
Healing Process ◽  
In Vivo Studies ◽  
Wound Healing Process ◽  
Fibroblast Cells ◽  
Plasma Exposure ◽  
Burn Wound ◽  
Degree Burn ◽  
Plasma Exposure Time

In this work, non-thermal N2/Ar micro-plasma was applied to fibroblast cells and second degree burn in mice to investigate the bio-safety and bioefficiency of micro-plasma device for studying wound healing process. The chosen parameters of the device were the addition of 0.5% N2 in argon plasma and RF supplied power of 17 W and 13 W in vitro and in vivo studies, respectively. Firstly, micro-plasma was applied to fibroblast cells and the induced biological effect was studied in vitro. The result showed that cells number increased three folds for plasma exposure time of 5 or 10 sec, followed by cell culture for 48 hrs. The cell coverage rate rose 20% for the same plasma exposure time, followed by cell culture for 6 or 12 hrs. Secondly, micro-plasma was applied to the second degree burn wound mice, followed by related ex vivo and in vivo assessments. For the former, 0.5% N2/Ar micro-plasma was competent to generate ROS/RNS signals for advancing healing process by the increase of ROS/RNS concentration around the plasma-exposed wound bed. The induced effect is most probably correlated with the angiogenesis and epithelialization processes of the burn wound on mice.

scholarly journals The Efficacy of Silver-Based Electrospun Antimicrobial Dressing in Accelerating the Regeneration of Partial Thickness Burn Wounds Using a Porcine Model

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3116
Author(s):  
Thien Do ◽  
Tien Nguyen ◽  
Minh Ho ◽  
Nghi Nguyen ◽  
Thai Do ◽  
...  
Keyword(s):  
Wound Healing ◽  
Burn Injury ◽  
Healing Process ◽  
Bactericidal Effect ◽  
Wound Healing Process ◽  
Burn Wounds ◽  
Partial Thickness Burn ◽  
Tissue Damages

(1) Background: Wounds with damages to the subcutaneous are difficult to regenerate because of the tissue damages and complications such as bacterial infection. (2) Methods: In this study, we created burn wounds on pigs and investigated the efficacy of three biomaterials: polycaprolactone-gelatin-silver membrane (PCLGelAg) and two commercial burn dressings, Aquacel® Ag and UrgoTulTM silver sulfadiazine. In vitro long-term antibacterial property and in vivo wound healing performance were investigated. Agar diffusion assays were employed to evaluate bacterial inhibition at different time intervals. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill assays were used to compare antibacterial strength among samples. Second-degree burn wounds in the pig model were designed to evaluate the efficiency of all dressings in supporting the wound healing process. (3) Results: The results showed that PCLGelAg membrane was the most effective in killing both Gram-positive and Gram-negative bacteria bacteria with the lowest MBC value. All three dressings (PCLGelAg, Aquacel, and UrgoTul) exhibited bactericidal effect during the first 24 h, supported wound healing as well as prevented infection and inflammation. (4) Conclusions: The results suggest that the PCLGelAg membrane is a practical solution for the treatment of severe burn injury and other infection-related skin complications.

scholarly journals Systemic and topical administration of spermidine accelerates skin wound healing

2020 ◽  
Author(s):  
Daisuke Ito ◽  
Hiroyasu Ito ◽  
Takayasu Ideta ◽  
Ayumu Kanbe ◽  
Soranobu Ninomiya ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Wound Healing ◽  
Wound Repair ◽  
Healing Process ◽  
Topical Administration ◽  
Skin Wound ◽  
Wound Healing Process ◽  
Skin Wound Healing

Abstract Background The skin wound healing process is regulated by various cytokines, chemokines, and growth factors. Recent reports have demonstrated that spermine/spermidine (SPD) promote wound healing through urokinase-type plasminogen activator (uPA)/uPA receptor (uPAR) signaling in vitro. Here, we investigated whether the systemic and topical administration of SPD would accelerate the skin wound-repair process in vivo.Methods A skin wound repair model was established using C57BL/6 J mice. SPD was mixed with white petrolatum for topical administration. For systemic administration, SPD mixed with drinking water was orally administered. Changes in wound size over time were calculated using digital photography.Results Systemic and topical SPD treatment significantly accelerated skin wound healing. The administration of SPD promoted the uPA/uPAR pathway in wound sites. Moreover, topical treatment with SPD enhanced the expression of IL-6 and TNF-α in wound sites. Scratch and cell proliferation assays revealed that SPD administration accelerated scratch wound closure and cell proliferation in vitro.Conclusion These results indicate that treatment with SPD promotes skin wound healing through activation of the uPA/uPAR pathway and induction of the inflammatory response in wound sites. The administration of SPD might contribute to new effective treatments to accelerate skin wound healing.

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