Tetracycline delivery from fibrin controls peritoneal infection without measurable systemic antibiotic

Sustained release of curcumin from fibrin matrix induces cancer cell death and immunomodulation

Despite the role of curcumin in controlling inflammation, angiogenesis, and cancer in human cells, its therapeutic use is limited. The reasons are quick metabolic breakdown, low aqueous solubility, and bioavailability. This study describes the advantages of clinical-grade curcumin-incorporated fibrin matrix either in lyophilized off-the-shelf wafer or injectable hydrogel forms, as a biodegradable local delivery system. To produce the curcumin-fibrin wafer, used clinical-grade fibrin sealant in a modified composition. To fabricate wafer, we premixed the curcumin with either fibrinogen or thrombin, before clotting into a hydrogel. Sustained release of active curcumin from fibrin wafer, suspended in culture medium at 37 °C lasted for seven days. Upon premixing albumin with thrombin and subsequently adding curcumin into the mixture improved the loading concentration and stability. Dose- and time-dependent apoptotic function of curcumin on cancer cell lines upon release from fibrin wafer, were demonstrated in vitro. In vivo immuno-modulation and a nontoxic response to curcumin released from fibrin into the peritoneal cavity of mice were established. The cytotoxic effect of released curcumin was demonstrated; showing both a preventive and therapeutic role against tumor growth. In vivo studies used Dalton's Lymphoma Ascites (DLA) mice model. Both implanted fibrin wafer and injected hydrogel can breakdown by a physiological process and get cleared by the fibrinolytic mechanism. The lyophilized fibrin wafer could function as a hemostat, adhere to surgical cancer tissues, and arrest bleeding. The potential of curcumin in preventing solid tumor metastasis may be explored upon the sustained delivery of the molecule from the fibrin wafer.

Fibrin Matrices as (Injectable) Biomaterials: Formation, Clinical Use, and Molecular Engineering

This review focuses on fibrin, starting from biological mechanisms (its production from fibrinogen and its enzymatic degradation), through its use as a medical device and as a biomaterial, and finally discussing the techniques used to add biological functions and/or improve its mechanical performance through its molecular engineering. Fibrin is a material of biological (human, and even patient's own) origin, injectable, adhesive, and remodellable by cells; further, it is nature's most common choice for an in situ forming, provisional matrix. Its widespread use in the clinic and in research is therefore completely unsurprising. There are, however, areas where its biomedical performance can be improved, namely achieving a better control over mechanical properties (and possibly higher modulus), slowing down degradation or incorporating cell-instructive functions (e.g., controlled delivery of growth factors). The authors here specifically review the efforts made in the last 20 years to achieve these aims via biomimetic reactions or self-assembly, as much via formation of hybrid materials.

Fibrin-based delivery strategies for acute and chronic wound healing

Fibrin, a natural hydrogel, is the end product of the physiological blood coagulation cascade and naturally involved in wound healing. Beyond its role in hemostasis, it acts as a local reservoir for growth factors and as a provisional matrix for invading cells that drive the regenerative process. Its unique intrinsic features do not only promote wound healing directly via modulation of cell behavior but it can also be fine-tuned to evolve into a delivery system for sustained release of therapeutic biomolecules, cells and gene vectors. To further augment tissue regeneration potential, current strategies exploit and modify the chemical and physical characteristics of fibrin to employ combined incorporation of several factors and their timed release. In this work we show advanced therapeutic approaches employing fibrin matrices in wound healing and cover the many possibilities fibrin offers to the field of regenerative medicine.

Antibacterial activity of antipsychotic agents, their association with lipid nanocapsules and its impact on the properties of the nanocarriers and on antibacterial activity

Bacterial antibiotic resistance is an emerging public health problem worldwide; therefore, new therapeutic strategies are needed. Many studies have described antipsychotic compounds that present antibacterial activity. Hence, the aims of this study were to evaluate the in vitro antibacterial activity of antipsychotics belonging to different chemical families, to assess the influence of their association with lipid nanocapsules (LNCs) on their antimicrobial activity as well as drug release and to study the uptake of LNCs by bacterial cells. Antibacterial activity was evaluated against Gram-positive Staphylococcus aureus and Gram negative Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii by minimum inhibitory concentration (MIC) assay, and the capability of killing tested microorganisms was evaluated by time kill assay. LNCs were prepared by phase inversion method, and the antipsychotic agents were incorporated using pre-loading and post-loading strategies. Only phenothiazines and thioxanthenes showed antibacterial activity, which was independent of antibiotic-resistance patterns. Loading the nanocarriers with the drugs affected the properties of the former, particularly their zeta potential. The release rate depended on the drug and its concentration-a maximum of released drug of less than 40% over 24 hours was observed for promazine. The influence of the drug associations on the antibacterial properties was concentration-dependent since, at low concentrations (high nanocarrier/drug ratio), the activity was lost, probably due to the high affinity of the drug to nanocarriers and slow release rate, whereas at higher concentrations, the activity was well maintained for the majority of the drugs. Chlorpromazine and thioridazine increased the uptake of the LNCs by bacteria compared with blank LNCs, even below the minimum inhibitory concentration.

Improved anti-tumor efficacy via combination of oxaliplatin and fibrin glue in colorectal cancer

Colorectal cancer is very common worldwide and advanced colorectal cancer exhibited very poor clinical outcome. Oxaliplatin (OXP) is one of the principal chemotherapeutic agents in colorectal cancer treatment presenting impressive anti-tumor ability, limited by adverse effect in clinical practice. Fibrin glue (FG) is a biocompatible formulation made of fibrinogen and thrombin, extensively used in surgery for hemostasis, tissue adhesion and sealing. In this study, FG was innovatively applied as OXP delivery system and results showed enhanced anti-tumor performance in subcutaneous model and abdominal metastasis model of murine colorectal cancer compared with that of OXP used alone. It is revealed that combination of OXP and FG could increase activated CD8⁺ T cells, reduce regulatory T (Treg) cells and increase interferon-γ (IFN-γ). Furthermore, results showed promoted tumor apoptosis, decreased proliferation and inhibited tumor angiogenesis by OXP and FG combination. No obvious systemic toxicity was observed in this study. Finally, our findings provided basis for promising application of OXP and FG combination in colorectal cancer treatment.

Sustained-released mixture of vascular endothelial growth factor 165 and fibrin glue strengthens healing of ileal anastomoses in a rabbit model with intraperitoneal infection

Purpose

To investigate the effects of a sustained-released mixture of vascular endothelial growth factor 165 (VEGF165) and fibrin glue (FG) local administration on postoperative rabbit ileal anastomoses.

Methods

One hundred twenty-eight male and female New Zealand white rabbits underwent intraperitoneal infection subsequent ileal anastomosis surgery were divided randomly into 4 groups, including 32 animals in each, applied with saline solution, FG, rhVEGF165 and a mixture of rhVEGF165 with FG (VEGF + FG) on the anastomoses, respectively. The incidences of anastomotic leakage were observed. Histopathological examination for inflammatory infiltration, fibroblast proliferation, and capillary vascular proliferation were performed. Then, bursting pressure and hydroxyproline concentrations were assessed in anastomoses sits on postoperative days 3, 5, 7, and 14.

Results

Rabbits in VEGF + FG group had the lowest incidence of leakage (P < 0.05). Histological evaluations revealed that granulation tissue was formed on days 5 after anastomosis; fibroblast proliferation and capillary vascular proliferation were significantly increased on days 7 and 14 in VEGF + FG group. Furthermore, there was a statistically significant difference in the mean bursting pressures between VEGF + FG group and other groups on days 7 and 14 (P < 0.05), and rabbits in VEGF + FG group exhibited a higher concentration than VEGF group (P < 0.05) and FG group (P < 0.05) on day 14.

Conclusion

Administration of VEGF165 mixed with FG to ileal anastomosis accelerates wound healing and enhances the anastomosis by increased angiogenesis.

Nanoparticle-Based Mycosis Vaccine

Many diseases that were considered major affliction of mankind in the past have been successfully eradicated with introduction of appropriate vaccine strategies. In order to expedite new challenges coming up to deal with various infectious diseases, nano-particulate-based subunit vaccines seem to be the demand of ordeal. The nano-vaccines can find better scope for the diseases that were not rampant in the semi-advanced world few years back. For example in present-day circumstances that corroborate with advancement in the field of medical sciences in terms of cancer chemotherapy, organ transplantation, therapy of autoimmune diseases, etc.; along with prevalence of altogether unheard diseases such as HIV infection, people are at risk of infliction with many more pathogens. In this regard, development of an effective prophylactic strategy against many opportunistic infections primarily caused by fungal pathogens needs better understanding of host pathogen relation and role of active immunity against pathogenic fungi. In the present study, we have tried to decipher effectiveness of a nano-sized vaccine delivery system in imparting protection against fungal pathogens.

Antifungal efficacy of amphotericin B encapsulated fibrin microsphere for treating Cryptococcus neoformans infection in Swiss albino mice

A natural and biocompatible fibrin microsphere is one of the most promising dual delivery vehicle as compared to other traditionally designed delivery modalities. It represents sustained delivery of encapsulated drug and is easily biodegradable in the blood circulation. In the present study, we evaluated the systemic augmentation of the antifungal activity of amphotericin B loaded in fibrin microsphere (AMB-fibrin microsphere) against cryptococcosis in Swiss albino mice. Mice infected with Cryptococcus neoformans were treated with 0.5mg/kg AMB-fibrin microsphere that was given alternately for 7 days. The antifungal potential of AMB-fibrin microsphere was assessed on the basis of reduction of cfu count in the systemic circulation and various vital organs of infected mice. The formulation was found to be highly effective in reducing intracellular pathogen from the experimental animals where fibrin microsphere significantly controlled the release of amphotericin B for longer time duration. The AMB-fibrin microsphere chemotherapy was significantly more effective than free amphotericin B in reducing the fungal burden and showed better survival efficacy (p<0.05). The current study demonstrating the use of novel amphotericin B loaded fibrin microsphere not only imparts protection to the encapsulated amphotericin B but also offers an effective strategy to decrease the drug associated toxicities.

Nanotechnology solutions to restore antibiotic activity

This review focuses on the development of nanoparticle systems that enables to enhance and restore the antibiotic activity for drug-resistant organisms. New and more aggressive antibiotic resistant bacteria and parasites calls for the development of new therapeutic strategies to overcome the inefficiency of conventional antibiotics and bypass treatment limitations related to these pathologies. Nanostructured biomaterials, nanoparticles in particular, have unique physicochemical properties such as ultra-small and controllable size, large surface area to mass ratio, high reactivity, and functionalizable structure. These properties can be applied to facilitate the administration of antimicrobial drugs, thereby overcoming some of the limitations in traditional antimicrobial therapeutics. Here the current progress and challenges in synthesizing nanoparticle platforms for restoring activity of various antimicrobial drugs are reviewed with an emphasis on antibiotics. We also call attention to the need to unite the shared interest between nanoengineers and microbiologists in developing nanotechnology for the treatment of microbial diseases.

Fibrin matrices: The versatile therapeutic delivery systems

Fibrin sealants, that have been employed for over a century by surgeons to stop post surgery bleeding, are finding novel applications in the controlled delivery of antibiotics and several other therapeutics. Fibrinogen can be easily purified from blood plasma and converted by thrombolysis to fibrin that undergoes spontaneous aggregation to form insoluble clot. During the gelling, fibrin can be formulated into films, clots, threads, microbeads, nanoconstructs and nanoparticles. Whole plasma clots in the form of beads and microparticles can also be prepared by activating endogenous thrombin, for possible drug delivery. Fibrin formulations offer remarkable scope for controlling the porosity as well as in vivo degradability and hence the release of the associated therapeutics. Binding/covalent-linking of therapeutics to the fibrin matrix, crosslinking of the matrix with bifunctional reagents and coentrapment of protease inhibitors have been successful in regulating both in vitro and in vivo release of the therapeutics. The release rates can also be remarkably lowered by preentrapment of therapeutics in insoluble particles like liposomes or by anchoring them to the matrix via molecules that bind them as well as fibrin.

The use of tissue sealants to deliver antibiotics to an orthopaedic surgical site with a titanium implant

BACKGROUND

Orthopaedic surgery is associated with unacceptable infection rates that respond poorly to systemic antibiotics. The objective of this study was to use an animal model for orthopaedic implant infection to examine the ability of a new-generation fibrin tissue sealant to effectively deliver antibiotics to the surgical site.

METHODS

The antibiotics cefazolin, fusidic acid or 5-fluorouracil were blended into Vitagel tissue sealant. The release rate of the drugs was measured using HPLC methods and bioactivity was measured by the zone of inhibition method with pathogenic Staphylococcus aureus. The antibiotic activity of the drug-loaded sealant was then tested in rats using infected orthopaedic surgical sites (titanium clip on spine). Efficacy was evaluated by residual bacterial counts on clips, clinical observations of infection, and histological findings.

RESULTS

The drugs were released in a controlled manner over 2-4 days. All three antibiotics demonstrated strong antibacterial activity when released from the sealants. None of the treated animals demonstrated systemic illness. Post mortem dissection revealed a well-encapsulated abscess surrounding the titanium clip with erosion of the bony process. Using an inoculum of 1-5 × 10(3) CFU, treatment with antibiotic-loaded fibrin sealant demonstrated reduced infective swelling and reduced bacterial counts on surgical clip swabs compared to control rats or rats treated with antibiotic only. This model allowed for almost 100 % infectivity with a 0 % mortality rate due to infection, mimicking the clinical features of human implant infection.

CONCLUSION

The results support the use of antibiotic-loaded commercially available fibrin sealants to prevent infection after implant surgery.

The use of antibiotic-impregnated fibrin sealant for the prevention of surgical site infection associated with spinal instrumentation

PURPOSE

The purpose of this study was to determine if the use of antibiotic-impregnated fibrin sealant (AFS) was effective in preventing surgical site infections (SSI) associated with spinal instrumentation.

METHODS

In a preliminary study, five pieces of vancomycin-impregnated fibrin sealant, five nuts that were not treated with the sealant, and five nuts that were treated with the sealant were subjected to agar diffusion testing. In a clinical study, the rates of deep SSI were compared between 188 patients who underwent procedures involving spinal instrumentation without AFS (group 1) and 196 patients who underwent procedures involving spinal instrumentation with AFS (group 2).

RESULTS

All five pieces of vancomycin-impregnated fibrin sealant and the five nuts treated with the sealant exhibited antimicrobial efficacy, while the five untreated nuts did not exhibit antimicrobial efficacy in the agar diffusion test. In the clinical study, 11 (5.8 %) of the 188 patients in group 1 acquired a deep SSI, while none (0 %) of the 196 patients in group 2 acquired a deep SSI.

CONCLUSION

The present study demonstrated that the application of AFS to spinal instrumentation yielded good clinical outcomes in terms of the prevention of postoperative spinal infections. It is hoped that limiting AFS use to patients requiring spinal instrumentation and those with risk factors for SSI will reduce the overall costs while preventing SSIs.

Beaded plasma clot: a potent sustained-release, drug-delivery system

Aim: The aim of the study was to prepare a drug-entrapped, beaded form of blood plasma for possible sustained drug delivery. Method: Blood plasma mixed with various drugs was enriched with CaCl2 and transferred in the form of small droplets on to a glass slide covered with parafilm. Clot formation was induced by incubation at 37°C. Results: Plasma-bead entrapped tetracycline, amphotericin B and daunorubicin were released gradually in vitro. Crosslinking of the beads with glutaraldehyde decreased the release rate of drugs remarkably. The plasma bead-entrapped cefotaxime administered subcutaneously in mice was released in a slow and sustained fashion and remained in circulation for a longer duration than the antibiotic administered in the free form. Conclusion: The plasma beads have potential for the sustained delivery of drugs in vivo, since their preparation does not require additional thrombin or other proteins and can be readily accomplished by using autologous plasma, thereby minimizing the risk of immunological complications.

Fibrin as a delivery system for therapeutic drugs and biomolecules

Fibrin is a natural biopolymer involved in the coagulation cascade. It acts as a reservoir for growth factors, cells, and enzymes during wound healing and provides a scaffold for the synthesis of extracellular matrix. Thus, the use of fibrin has expanded in recent years from traditional use as a sealant for surgical applications, to a tissue engineering scaffold capable of providing nature's cues for tissue regeneration. This paper reviews the advantageous biological aspects of fibrin, the history of the scaffold material, and its present role in the delivery of drugs, growth factors, cells, and gene vectors. Examples are given of studies where the structure and form of the scaffold have been manipulated for optimal release of the therapeutic agent, optimal cellular activity, and investigation into stem cell differentiation. It is evident from the body of literature presented that the benefits of fibrin are being exploited for a vast range of tissue engineering applications and that fibrin remains a key scaffold material for the delivery of drugs and biomolecules.

Strategy for prevention of local recurrence of pancreatic cancer after pancreatectomy: antitumor effect of gemcitabine mixed with fibrin glue in an orthotopic nude mouse model

BACKGROUND

Pancreatic cancer frequently recurs after operative treatment, resulting in a poor prognosis. Inhibition of proliferation of residual cancer cells is important for improved survival of patients with pancreatic cancer. Fibrin glue (FG) is a biocompatible, adherent hemostat that can deliver high concentrations of anticancer drugs to residual cancer cells. The aim of this study was to evaluate the local antitumor effect of a mixture of gemcitabine (GEM) and FG on pancreatic cancer cells implanted orthotopically in nude mice.

METHODS

SUIT-2 human pancreatic cells were injected into the tail of the pancreas of nude mice. Seven days later, groups of mice were treated with 80 mg/kg GEM mixed with 0.5 mL fibrin glue (GEM + FG), 0.5 mL FG alone (FG), single intraperitoneal (i.p.) injection of 80 mg/kg GEM (GEM1), i.p. injection of 80 mg/kg GEM weekly for 3 weeks (GEM1,2,3), GEM + FG followed by weekly GEM injections for 2 weeks (GEM + FG + GEM2,3), or i.p. injection of PBS weekly for 3 weeks (controls).

RESULTS

Twenty-eight days after cell injections, tumor volumes of groups treated with GEM + FG + GEM2,3, GEM1,2,3, GEM + FG, GEM1, and FG were decreased by 84%, 70%, 62%, 37%, and 10%, respectively, compared to that of control mice. GEM + FG + GEM2,3 had the strongest anticancer effect compared to all other groups (P < .05). Additionally, GEM + FG showed a more potent antitumor effect compared to GEM1 (P < .05). Survival of mice treated with GEM + FG + GEM2,3 was longer than that of mice in all other groups (P < .05).

CONCLUSIONS

A mixture of GEM and FG was effective in inhibiting the growth of orthotopically implanted pancreatic neoplasms in nude mice. This procedure may be useful clinically to prevent the local recurrence of pancreatic cancer after pancreatectomy.

Interactions of carboplatin with fibrin(ogen), implications for local slow release chemotherapy

The effect of carboplatin (CPt) on fibrin(ogen) clot formation and the possible use of this combination for local slow release chemotherapy were examined. CPt significantly reduced thrombin-induced fibrin clotting time (CT) and increased clot turbidity in a concentration-dependent manner. When CPt was mixed with physiological levels of fibrinogen (>1 mg/ml), electron-dense nanoparticles (3 nm) were formed, as demonstrated by both optical particle counter and transmission electron microscopy (TEM). Upon thrombin-induced coagulation, the CPt nanoparticles were trapped within the fibrin mesh. At higher fibrinogen levels (>5 mg/ml), the 3-nm CPt nanoparticles aggregated, so that approximately 2% and approximately 0.5% of the CPt on the fibrinogen appeared as larger particles of 10 and 50 nm, respectively. Dialysis experiments showed that 60-70% of the CPt was released from the fibrin clot within one hour as a non-particulate soluble form, while approximately 30% of particulate CPt were retained. Up to 5 mg/ml this portion of firmly attached CPt was dependent of the initial drug level. CPt released from the fibrin by either diffusion or by fibrinolysis exhibited cytotoxic activity towards retinoblastoma (RB) cell lines (Y-79 and Weri RB1) equivalent to free drug. Our study indicates that CPt enhances fibrin clot formation and suggests the use of fibrin with high dose CPt for slow release chemotherapy against localized tumors such as retinoblastoma.

Factor XIIIa Incorporates Thymosin β4 Preferentially into the Fibrin(ogen) αC-Domains

It was shown recently that tissue transglutaminase and presumably plasma transglutaminase, factor XIIIa, can covalently incorporate into fibrin(ogen) a physiologically active peptide, thymosin beta(4) [(Huff et al. (2002) FASEB J. 16, 691-696]. To clarify the mechanism of this incorporation, we studied the interaction of thymosin beta(4) with fibrinogen, fibrin, and their recombinant fragments, the gamma-module (gamma-chain residues 148-411), and the alphaC-domain (Aalpha-chain residues 221-610) and its truncated variants by immunoblot and ELISA. No significant noncovalent interaction between them was detected in the absence of activated factor XIII, while in its presence thymosin beta(4) was effectively incorporated into fibrin and to a lesser extent into fibrinogen. The incorporation at physiological concentrations of fibrin(ogen) and factor XIII was significant with molar incorporation ratios of thymosin beta(4) to fibrinogen and fibrin of 0.2 and 0.4, respectively. Further experiments revealed that although activated factor XIII incorporates thymosin beta(4) into the isolated gamma-module and alphaC-domain, in fibrin the latter serves as the major incorporation site. This site was further localized to the COOH-terminal portion of the alphaC-domain including residues 392-610.