Diesel exhaust exposure induces angiogenesis

Our aim was to test the hypothesis that exposure to whole diesel exhaust (WDE) would enhance angiogenesis/vasculogenesis. Male apolipoprotein E-deficient mice, with either scaffold implantation subcutaneously or hindlimb ischemia, were exposed to either WDE (containing diesel exhaust particle [DEP] at a concentration of about 1 mg/m³) or filtered air 6 h/day, 5 days/week in a whole body exposure chamber for 2, 5, or 8 weeks, respectively. WDE exposure significantly increased total cell counts in the scaffolds, aortic, and perivascular fat tissues. Macrophage infiltration was enhanced and CD31 expression increased in the scaffolds, which was coupled by increased α-smooth muscle actin (α-SMA) expression. WDE exposure led to increased CD31 expression, while decreasing endothelial nitric oxide synthase in the aortic wall. The vessel volume measured by micro-CT was increased in ischemic and non-ischemic hindlimbs in response to WDE exposure. DEP exposure induced capillary-like tube formation in endothelial cells in vitro, and caused capillary sprouting from aortic rings ex vivo. In addition, WDE exposure significantly increased mRNA expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF)-1α, while decreasing prolylhydroxylase (PHD) 2 expression. WDE exposure increases inflammatory cell infiltration, enhances the vessel volume/flow, and increases capillary tube formation and sprouting, thereby inducing angiogenesis and vasculogenesis. The angiogenic effects may occur through increasing HIF-1α and VEGF while decreasing PHD2 expression.     

Spatio–temporal VEGF and PDGF Delivery Patterns Blood Vessel Formation and Maturation

Purpose Biological mechanisms of tissue regeneration are often complex, involving the tightly coordinated spatial and temporal presentation of multiple factors. We investigated whether spatially compartmentalized and sequential delivery of factors can be used to pattern new blood vessel formation. Materials and Methods A porous bi-layered poly(lactide–co-glycolide) (PLG) scaffold system was used to locally present vascular endothelial growth factor (VEGF) alone in one spatial region, and sequentially deliver VEGF and platelet-derived growth factor (PDGF) in an adjacent region. Scaffolds were implanted in severely ischemic hindlimbs of SCID mice for 2 and 6 weeks, and new vessel formation was quantified within the scaffolds. Results In the compartment delivering a high dose of VEGF alone, a high density of small, immature blood vessels was observed at 2 weeks. Sequential delivery of VEGF and PDGF led to a slightly lower blood vessel density, but vessel size and maturity were significantly enhanced. Results were similar at 6 weeks, with continued remodeling of vessels in the VEGF and PDGF layer towards increased size and maturation. Conclusions Spatially localizing and temporally controlling growth factor presentation for angiogenesis can create spatially organized tissues.     

Liposomal angiogenic peptides for ischemic limb perfusion: comparative study between different administration methods

Background: We investigated the therapeutic effectiveness of PEGylated liposomes loaded with angiogenic peptides for treating hindlimb ischemia.

Methods: Rats received a femoral artery occlusion. Red blood cells collected from the animals were labeled with technetium-99m. Limb perfusion gamma imaging was performed. PEGylated liposomes loaded with angiogenic peptides were administered intra-arterially. Technetium-99m red blood cell imaging was repeated 1 week later. The animals were sacrificed the next day. The expression of angiogenic proteins was studied. Later, changes in limb perfusion after intra-arterial infusion versus intra-muscular injection were also compared to determine the therapeutic effectiveness of different administration methods.

Results: Femoral artery occlusion dramatically reduced ischemic limb perfusion (by an average of 69%, compared to contralateral limb). This was not different among groups (p?>?0.05). Liposomes loaded with angiogenic peptides significantly improved ischemic limb perfusion, compared to controls (210% of baseline, versus 100% of baseline in control; p?<?0.05 versus controls). The enhanced ischemic limb perfusion was accompanied by an increased expression of CD 31 (an average of 1.6-fold increase of controls; p?<?0.05). The liposomes or peptides treatment alone did not affect ischemic perfusion (liposomes alone: 100% of baseline; peptides alone: 120% of baseline; p?>?0.05 versus controls, respectively) or the angiogenic response (1.1-fold of controls in liposomes alone; 1.0-fold of controls in peptides alone; p?>?0.05 versus controls, respectively). Intra-muscular injection induced similar liposomal treatment effects on ischemic limb perfusion (230% of baseline) as those by intra-arterial infusion (210% of baseline; p?<?0.05 versus intra-muscular).

Conclusions: PEGylated liposomes loaded with angiogenic peptides improved ischemic limb perfusion and promoted angiogenic responses. Liposomal angiogenic treatment via intra-arterial infusion resulted in an equally effective therapeutic efficacy compared to that of intra-muscular injection. These results show the therapeutic potential of our liposomal strategy for treating peripheral limb ischemia.     

Co-delivery of Vascular Endothelial Growth Factor and Angiopoietin-1 Using Injectable Microsphere/Hydrogel Hybrid Systems for Therapeutic Angiogenesis

Purpose

We hypothesized that combined delivery of vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) using microsphere/hydrogel hybrid systems could enhance mature vessel formation compared with administration of each factor alone.

Methods

Hybrid delivery systems composed of alginate hydrogels and poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres containing angiogenic factors were prepared. The release behavior of angiogenic factors from hybrid systems was monitored in vitro. The hybrid systems were injected into an ischemic rodent model, and blood vessel formation at the ischemic site was evaluated.

Results

The sustained release over 4 weeks of both VEGF and Ang-1 from hybrid systems was achieved in vitro. Co-delivery of VEGF and Ang-1 was advantageous to retain muscle tissues and significantly induced vessel enlargement at the ischemic site, compared to mice treated with either VEGF or Ang-1 alone.

Conclusions

Sustained and combined delivery of VEGF and Ang-1 significantly enhances vessel enlargement at the ischemic site, compared with sustained delivery of either factor alone. Microsphere/hydrogel hybrid systems may be a promising vehicle for delivery of multiple drugs for many therapeutic applications.     

VEGF-controlled release within a bone defect from alginate/chitosan/PLA-H scaffolds

VEGF and its receptors constitute the key signaling system for angiogenic activity in tissue formation, but a direct implication of the growth factor in the recruitment, survival and activity of bone forming cells has also emerged. For this reason, we developed a composite (alginate/chitosan/PLA-H) system that controls the release kinetics of incorporated VEGF to enhance neovascularization in bone healing. VEGF release kinetics and tissue distribution were determined using iodinated (¹²⁵I) growth factor. VEGF was firstly encapsulated in alginate microspheres. To reduce the high in vitro burst release, the microspheres were included in scaffolds. Matrices were prepared with alginate (A-1, A-2), chitosan (CH-1, CH-2) or by coating the CH-1 matrix with a PLA-H (30 kDa) film (CH-1-PLA), the latter one optimally reducing the in vitro and in vivo burst effect. The VEGF in vitro release profile from CH-1-PLA was characterized by a 13% release within the first 24 h followed by a constant release rate throughout 5 weeks. For VEGF released from composite scaffolds in vitro, bioactivity was maintained above 90% of the expected value. Despite the fact that the in vivo release rate was slightly faster, a good in vitro–in vivo correlation was found. The VEGF released from CH-1 and CH-1-PLA matrices implanted into the femurs of rats remained located around the implantation site with a negligible systemic exposure. These scaffolds provided a bone local GF concentration above 10 ng/g during 2 and 5 weeks, respectively, in accordance to the in vivo release kinetics. Our data show that the incorporation of VEGF into the present scaffolds allows for a controlled release rate and localization of the GF within the bone defect.     

The Implantable and Biodegradable PHBHHx 3D Scaffolds Loaded with Protein-Phospholipid Complex for Sustained Delivery of Proteins

Purpose

PHBHHx (poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)) is an excellent biomaterial for tissue repair. Here, we aim to develop a PHBHHx-based three-dimensional (3D) scaffold system for sustained delivery of proteins (insulin serves as a model protein).

Methods

The insulin-phospholipid complex (INS-PLC) was prepared to enhance the insulin lipophilicity. INS-PLC loaded PHBHHx 3D scaffolds (INS-PLC-SCAs) containing PEG-2000 were fabricated by lyophilization. In vitro release was performed in the medium with or without lipase. The bioactivity of INS-PLC-SCAs was measured in diabetic rats.

Results

In vitro release shows that the release rate of INS-PLC-SCAs was very slow (~6% of total insulin was released within 120 days), and PEG-2000 or lipase had no effect on its release pattern. The bioactivity test shows that the hypoglycaemic effect of insulin was maintained after formulated into scaffolds. After subcutaneous (s.c.) implantation, its therapeutic effect lasted for over 130 h, and its bioavailability was enhanced by 4-fold.

Conclusions

PHBHHx based 3D scaffold has a great potential for sustained delivery of proteins, especially growth factors. When growth factors are incorporated, it can serve as a bifunctional system that provides a porous skeleton for cells attachment and proliferation, as well as a matrix for long term release of the loaded growth factors.     

Composite polymer-bioceramic scaffolds with drug delivery capability for bone tissue engineering

Introduction: Next-generation scaffolds for bone tissue engineering (BTE) should exhibit the appropriate combination of mechanical support and morphological guidance for cell proliferation and attachment while at the same time serving as matrices for sustained delivery of therapeutic drugs and/or biomolecular signals, such as growth factors. Drug delivery from BTE scaffolds to induce the formation of functional tissues, which may need to vary temporally and spatially, represents a versatile approach to manipulating the local environment for directing cell function and/or to treat common bone diseases or local infection. In addition, drug delivery from BTE is proposed to either increase the expression of tissue inductive factors or to block the expression of others factors that could inhibit bone tissue formation. Composite scaffolds which combine biopolymers and bioactive ceramics in mechanically competent 3D structures, including also organic–inorganic hybrids, are being widely developed for BTE, where the affinity and interaction between biomaterials and therapeutic drugs or biomolecular signals play a decisive role in controlling the release rate.

Areas covered: This review covers current developments and applications of 3D composite scaffolds for BTE which exhibit the added capability of controlled delivery of therapeutic drugs or growth factors. A summary of drugs and biomolecules incorporated in composite scaffolds and approaches developed to combine biopolymers and bioceramics in composites for drug delivery systems for BTE is presented. Special attention is given to identify the main challenges and unmet needs of current designs and technologies for developing such multifunctional 3D composite scaffolds for BTE.

Expert opinion: One of the major challenges for developing composite scaffolds for BTE is the incorporation of a drug delivery function of sufficient complexity to be able to induce the release patterns that may be necessary for effective osseointegration, vascularization and bone regeneration. Loading 3D scaffolds with different biomolecular agents should produce a codelivery system with different, predetermined release profiles. It is also envisaged that the number of relevant bioactive agents that can be loaded onto scaffolds will be increased, whilst the composite scaffold design should exploit synergistically the different degradation profiles of the organic and inorganic components.     

Sustained Release of Multiple Growth Factors from Injectable Polymeric System as a Novel Therapeutic Approach Towards Angiogenesis

Purpose  

The aim was to investigate that a bio-degradable alginate and poly lactide-co-glycolide (PLG) system capable of delivering growth factors sequentially would be superior to single growth factor delivery in promoting neovascularization and improving perfusion.     

<Emphasis Type="Italic">In vitro / in vivo</Emphasis> evaluation of NCDS-micro-fabricated biodegradable implant

Using the nano-composite deposition system (NCDS) as a microfabrication technique, implantable scaffolds were prepared with poly(DL-lactide-co-glycolide)(85:15) [PLGA(85:15)] as a biodegradable polymer. 5-Fluorouracil (5-FU) was used as a model drug, and hydroxyapatite (HA) was incorporated as a release modifier. In vitro drug release was evaluated and we confirmed that HA could control the release of drug from the prepared scaffolds, especially in the initial phase of the release. Furthermore, in vivo tests demonstrated that the microfabricated scaffold with pores was useful in reducing immune response and maintained its original shape, indicating that the drug delivery system was highly biocompatible.     

Elastase-Sensitive Elastomeric Scaffolds with Variable Anisotropy for Soft Tissue Engineering

Purpose  To develop elastase-sensitive polyurethane scaffolds that would be applicable to the engineering of mechanically active soft tissues. Methods  A polyurethane containing an elastase-sensitive peptide sequence was processed into scaffolds by thermally induced phase separation. Processing conditions were manipulated to alter scaffold properties and anisotropy. The scaffold’s mechanical properties, degradation, and cytocompatibility using muscle-derived stem cells were characterized. Scaffold in vivo degradation was evaluated by subcutaneous implantation. Results  When heat transfer was multidirectional, scaffolds had randomly oriented pores. Imposition of a heat transfer gradient resulted in oriented pores. Both scaffolds were flexible and relatively strong with mechanical properties dependent upon fabrication conditions such as solvent type, polymer concentration and quenching temperature. Oriented scaffolds exhibited anisotropic mechanical properties with greater tensile strength in the orientation direction. These scaffolds also supported muscle-derived stem cell growth more effectively than random scaffolds. The scaffolds expressed over 40% weight loss after 56 days in elastase containing buffer. Elastase-sensitive scaffolds were complete degraded after 8 weeks subcutaneous implantation in rats, markedly faster than similar polyurethanes that did not contain the peptide sequence. Conclusion  The elastase-sensitive polyurethane scaffolds showed promise for application in soft tissue engineering where controlling scaffold mechanical properties and pore architecture are desirable.     

Adsorption of a Novel Recombinant Glycoprotein from HIV (Env gp120dV2 SF162) to Anionic PLG Microparticles Retains the Structural Integrity of the Protein,Whereas Encapsulation in PLG Microparticles Does Not

No HeadingPurpose. To evaluate the delivery of a novel HIV-1 antigen (gp120dV2 SF162) by surface adsorption or encapsulation within polylactide-co-glycolide microparticles and to compare both the formulations for their ability to preserve functional activity as measured by binding to soluble CD4.Methods. Poly(lactide-co-glycolide) microparticles were synthesized by a water-in-oil-in-water (w/o/w) emulsification method in the presence of the anionic surfactant dioctylsulfosuccinate (DSS) or polyvinyl alcohol. The HIV envelope glyocoprotein was adsorbed and encapsulated in the PLG particles. Binding efficiency and burst release measured to determine adsorption characteristics. The ability to bind CD4 was assayed to measure the functional integrity of gp120dV2 following different formulation processes.Results. Protein (antigen) binding to PLG microparticles was influenced by both electrostatic interaction and other mechanisms such as hydrophobic attraction and structural accommodation of the polymer and biomolecule. The functional activity as measured by the ability of gp120dV2 to bind CD4 was maintained by adsorption onto anionic microparticles but drastically reduced by encapsulation.Conclusions. The antigen on the adsorbed PLG formulation maintained its binding ability to soluble CD4 in comparison to encapsulation, demonstrating the feasibility of using these novel anionic microparticles as a potential vaccine delivery system.     

Design and in vivo evaluation of an indapamide transdermal patch

The aim of the present study was to develop and evaluate a novel drug-in-adhesive transdermal patch system for indapamide. Initial in vitro experiments were conducted to optimize formulation parameters prior to transdermal delivery in rats. The effects of the type of adhesive and the content of permeation enhancers on indapamide transport across excised rat skin were evaluated. The results indicated that DURO-TAK^® adhesive 87-2852 is a suitable and compatible polymer for the development of transdermal drug delivery systems for indapamide. The final formulation contained 4% N-dodecylazepan-2-one, 6% l-menthol and 3% isopropyl myristate. For in vivo studies patch systems were administered transdermally to rats while orally administered indapamide in suspension was used as a control. The PK parameters, such as the maximum blood concentration (C_max), time to reach the peak blood concentration (T_max), mean residence time (MRT), area under the curve (AUC_0–t) and terminal elimination half-life (T_1/2) were significantly (p < 0.05) different following transdermal administration compared with oral administration. In contrast to oral delivery, a sustained activity was observed over a period of 48 h after transdermal administration. This sustained activity was due to the controlled release of drug into the systemic circulation following transdermal administration.     

Drug delivery in soft tissue engineering

Introduction: Tissue defects, sustained through disease or trauma, present enormous challenges in regenerative medicine. Modern tissue engineering (TE) aims at replacing or repairing these defects through a combined approach of biodegradable scaffolds, suitable cell sources and appropriate environmental cues, such as biomolecules presented on scaffold surfaces or sustainably released from within.

Areas covered: This review provides a brief overview of the various drugs and bioactive molecules of interest to TE, as well as a selection of materials that have been proposed for TE scaffolds and matrices in the past. It then proceeds to discuss encapsulation, immobilization and controlled release strategies for bioactive proteins, before discussing recent advances in this area with a special focus on soft TE.

Expert opinion: Overall, minimal clinical success has been achieved so far in using growth factor, morphogen, or adhesion factor modified scaffolds and matrices; only one growth factor delivery system (Regranex Gel), has been approved by the FDA for clinical use, with only a handful of other growth factors being approved for human use so far. However, many more growth factors are currently in clinical Phase I – II or preclinical trials and many delivery systems utilize materials already approved by the FDA for other purposes. With respect to drug delivery in soft TE, a combination of increased research efforts in hydrogel and support material development as well as growth factor development is needed before clinical success is realized.     

Brain protection against ischemic stroke using choline as a new molecular bypass treatment

Aim:

To determine whether administration of choline could attenuate brain injury in a rat model of ischemic stroke and the underlying mechanisms.

Methods:

A rat model of ischemic stroke was established through permanent middle cerebral artery occlusion (pMCAO). After the surgery, the rats were treated with choline or choline plus the specific α7 nAChR antagonist methyllycaconitine (MLA), or with the control drug nimodipine for 10 days. The neurological deficits, brain-infarct volume, pial vessel density and the number of microvessels in the cortex were assessed. Rat brain microvascular endothelial cells (rBMECs) cultured under hypoxic conditions were used in in vitro experiments.

Results:

Oral administration of choline (100 or 200 mg·kg⁻¹·d⁻¹) or nimodipine (20 mg·kg⁻¹·d⁻¹) significantly improved neurological deficits, and reduced infarct volume and nerve cell loss in the ischemic cerebral cortices in pMCAO rats. Furthermore, oral administration of choline, but not nimodipine, promoted the pial arteriogenesis and cerebral-cortical capillary angiogenesis in the ischemic regions. Moreover, oral administration of choline significantly augmented pMCAO-induced increases in the expression levels of α7 nAChR, HIF-1α and VEGF in the ischemic cerebral cortices as well as in the serum levels of VEGF. Choline-induced protective effects were prevented by co-treatment with MLA (1 mg·kg⁻¹·d⁻¹, ip). Treatment of rBMECs cultured under hypoxic conditions in vitro with choline (1, 10 and 100 μmol/L) dose-dependently promoted the endothelial-cell proliferation, migration and tube formation, as well as VEGF secretion, which were prevented by co-treatment with MLA (1 μmol/L) or by transfection with HIF-1α siRNA.

Conclusion:

Choline effectively attenuates brain ischemic injury in pMCAO rats, possibly by facilitating pial arteriogenesis and cerebral-cortical capillary angiogenesis via upregulating α7 nAChR levels and inducing the expression of HIF-1α and VEGF.     

CXCL1 microspheres: a novel tool to stimulate arteriogenesis

Context: After arterial occlusion, diametrical growth of pre-existing natural bypasses around the obstruction, i.e. arteriogenesis, is the body’s main coping mechanism. We have shown before that continuous infusion of chemokine (C-X-C motif) ligand 1 (CXCL1) promotes arteriogenesis in a rodent hind limb ischemia model.

Objective: For clinical translation of these positive results, we developed a new administration strategy of local and sustained delivery. Here, we investigate the therapeutic potential of CXCL1 in a drug delivery system based on microspheres.

Materials and methods: We generated poly(ester amide) (PEA) microspheres loaded with CXCL1 and evaluated them in vitro for cellular toxicity and chemokine release characteristics. In vivo, murine femoral arteries were ligated and CXCL1 was administered either intra-arterially via osmopump or intramuscularly encapsulated in biodegradable microspheres. Perfusion recovery was measured with Laser-Doppler.

Results: The developed microspheres were not cytotoxic and displayed a sustained chemokine release up to 28?d in vitro. The amount of released CXCL1 was 100-fold higher than levels in native ligated hind limb. Also, the CXCL1-loaded microspheres significantly enhanced perfusion recovery at day 7 after ligation compared with both saline and non-loaded conditions (55.4?±?5.0% CXCL1-loaded microspheres versus 43.1?±?4.5% non-loaded microspheres; n?=?8–9; p?<?0.05). On day 21 after ligation, the CXCL1-loaded microspheres performed even better than continuous CXCL1 administration (102.1?±?4.4% CXCL1-loaded microspheres versus 85.7?±?4.8% CXCL1 osmopump; n?=?9; p?<?0.05).

Conclusion: Our results demonstrate a proof of concept that sustained, local delivery of CXCL1 encapsulated in PEA microspheres provides a new tool to stimulate arteriogenesis in vivo.     

Insulin-like Growth Factor I—Releasing Alginate-Tricalciumphosphate Composites for Bone Regeneration

Purpose Development and characterization of an in situ–forming, osteoconductive, and growth factor–releasing bone implant.Methods Injectable in situ–forming scaffolds were prepared from a 2% (m/v) alginate solution, tricalciumphosphate (TCP) granules, and poly(lactide-co-glycolide) microspheres (MS), loaded with the osteoinductive growth factor insulin-like growth factor I (IGF-I). Scaffolds were prepared by mixing the components followed by hydrogel formation through calcium carbonate–induced physical cross-linking of the alginate at slightly acidic pH. Physical-chemical properties and cell biocompatibility using osteoblast-like cells (MG-63 and Saos-2) of these scaffolds were investigated.Results The addition of TCP to the alginate resulted in reduced swelling and gelation time and an increase in stiffness. Osteoblast-like cells (MG-63 and Saos-2) did not show toxic reactions and adhered circumferentially to the TCP granules surface. The addition of the IGF-I MS resulted in an up to sevenfold increased proliferation rate of MG-63 cells as compared to scaffold preparations without IGF-I MS. The alkaline phosphate (ALP) activity—a parameter for osteblastic activity—increased with increasing amounts of TCP in Saos-2 loaded composite scaffolds.Conclusions A prototype in situ–hardening composite system for conformal filling of bone defects supporting osteoblastic activity for further clinical testing in relevant fracture models was developed and characterized.     

Poly(ethylene glycol)-Modified Proteins: Implications for Poly(lactide-co-glycolide)-Based Microsphere Delivery

The reduced injection frequency and more nearly constant serum concentrations afforded by sustained release devices have been exploited for the chronic delivery of several therapeutic peptides via poly(lactide-co-glycolide) (PLG) microspheres. The clinical success of these formulations has motivated the exploration of similar depot systems for chronic protein delivery; however, this application has not been fully realized in practice. Problems with the delivery of unmodified proteins in PLG depot systems include high initial “burst” release and irreversible adsorption of protein to the biodegradable polymer. Further, protein activity may be lost due to the damaging effects of protein-interface and protein-surface interactions that occur during both microsphere formation and release. Several techniques are discussed in this review that may improve the performance of PLG depot delivery systems for proteins. One promising approach is the covalent attachment of poly(ethylene glycol) (PEG) to the protein prior to encapsulation in the PLG microspheres. The combination of the extended circulation time of PEGylated proteins and the shielding and potential stabilizing effects of the attached PEG may lead to improved release kinetics from PLG microsphere system and more complete release of the active conjugate.     

Improving Protein Delivery from Microparticles Using Blends of Poly(DL lactide co-glycolide) and Poly(ethylene oxide)-poly(propylene oxide) Copolymers

Purpose. Microparticles containing ovalbumin as a model for protein drugs were formulated from blends of poly(DL lactide-co-glycolide) and poly(ethylene oxide)-poly(propylene oxide) copolymers (Pluronic). The objectives were to achieve uniform release characteristics and improved protein delivery capacity. Methods. The water- in oil -in oil emulsion/solvent extraction technique was used for microparticle production. Results. A protein loading level of over 40% (w/w) was attained in microparticles having a mean diameter of approximately 5 µm. Linear protein release profiles over 25 days in vitro were exhibited by certain blend formulations incorporating hydrophilic Pluronic F127. The release profile tended to plateau after 10 days when the more hydrophobic Pluronic L121 copolymer was used to prepare microparticles. A delivery capacity of 3 µg OVA/mg particles/ day was achieved by formulation of microparticles using a 1:2 blend of PLG:Pluronic F127. Conclusions. The w/o/o formulation approach in combination with PLG:Pluronic blends shows potential for improving the delivery of therapeutic proteins and peptides from microparticulate systems. Novel vaccine formulations are also feasible by incorporation of Pluronic L121 in the microparticles as a co-adjuvant.     

Carbon nanofiber amalgamated 3D poly-ε-caprolactone scaffold functionalized porous-nanoarchitectures for human meniscal tissue engineering: In vitro and in vivo biocompatibility studies

We developed customizable biomolecule functionalized 3D poly-ε-caprolactone (PCL) scaffolds reinforced with carbon nanofibers (CNF) for human meniscal tissue engineering. 3D nanocomposite scaffolds exhibited commendable mechanical integrity and electrical properties with augmented cytocompatibility. Especially, the functionalized 3D (10wt% CNF) scaffolds showed ~363% increase in compressive moduli compared to the pristine PCL. In dynamic mechanical analysis, these scaffolds achieved highest value (~42 MPa at 10 Hz) among all tested scaffolds including pristine PCL and human menisci (33, 41, 56 years). In vitro results were well supported by the outcomes of cell proliferation analysis, microscopic images, Hoechst staining and extracellular-matrix estimation. Further, in vivo rabbit bio toxicity studies revealed scaffold’s non-toxicity and its future potential as a meniscus scaffold. This study also indicates that the incorporation of CNF in polymer matrix may be optimized based on mechanical properties of patient meniscus and it may help in developing the customized patient specific 3D constructs with improved multifunctional properties.     

Effect of antibody against integrin α4 on bleomycin-induced pulmonary fibrosis in mice

Integrins are a family of transmembrane glycoproteins that can interact with components of the extracellular matrix. The α4β1 and α4β7 integrins are heterodimeric leukocyte cell surface molecules critical to their cell and matrix adhesive interactions. Evidence for a central role for the α4 integrins in leukocyte pathophysiology in the lung is well documented. In this study, we tested the hypothesis that neutralizing antibody for integrin α4 (PS2) may reduce bleomycin (BL)-induced lung fibrosis in vivo. Male C57BL/6 mice were injected intratracheally with saline (SA) or BL (0.08 U/mouse) followed by intraperitoneal injection of SA, isotype control antibody (1E6), or PS2 (100 μg) three times a week. Twenty-one days after the intratracheal instillation, mice were killed for bronchoalveolar lavage (BAL), biochemical, histopathological, and immunohistological analyses. Treatment with PS2 significantly reduced BL-induced increases in lung lipid peroxidation and hydroxyproline content. Lung histopathology also showed reduced fibrotic lesions in the BL-treated lungs by treatment with PS2. BL-treated mouse lungs also showed induction of cells with the myofibroblast phenotype, as indicated by the increased expression of α-smooth muscle actin (αSMA), whereas treatment with PS2 minimized the BL-induced αSMA expression. Furthermore, treatment with PS2 reduced the BL-induced increase in the BAL total cell number, and attenuated the BL-induced increase in the BAL protein level. It is concluded that integrin α4 may play an important role in BL-induced pulmonary fibrosis, and the use of anti-α4 antibody offers therapeutic antifibrotic potential in vivo.