Topical caspofungin for treatment of keratitis caused by Candida albicans in a rabbit model

Candida albicans is the most frequent cause of fungal keratitis in temperate regions. Caspofungin has potent activity against Candida spp. in a variety of clinical settings. Little is known, however, about its activity against fungal keratitis. We compared the efficacy of topical caspofungin with that of topical amphotericin B (AMB) in a rabbit model of experimental keratomycosis. Keratitis was induced with a standardized inoculum of Candida albicans (SC 5314) placed on the debrided cornea. Twenty-four hours after infection, animals were randomly assigned to treatment with 0.15% caspofungin, 0.5% caspofungin, 0.15% AMB, and a saline control (n = 12 rabbits in each group). For the first 12 h, treatment was repeated every 30 min and, after a 12-h pause, was resumed at hourly intervals for another 12 h. The animals were examined and killed 12 h after administration of the last dose. Treatment effects were evaluated by clinical assessment, fungal culture, and histopathology. Drug treatment significantly reduced corneal fungal recovery from 3.78 log10 CFU in saline-treated animals to 2.97, 1.76, and 1.18 log10 CFU in animals treated with 0.15% caspofungin, 0.5% caspofungin, and 0.15% AMB, respectively. By histopathology, the mean hyphal density was significantly lower in the corneas of treated animals than in those of the controls; there was no difference in hyphal densities between the different treatment groups. The depth of corneal invasion was not significantly reduced by the antifungal treatments. By clinical assessment, keratitis progressed in animals treated with saline, whereas disease progression was inhibited by all drug treatment regimens. In our rabbit model, 0.5% caspofungin was as effective as 0.15% AMB for the topical treatment of Candida keratitis. The potential clinical efficacy of caspofungin awaits further investigation.

Electroporation enhances reporter gene expression following delivery of naked plasmid DNA to the lung

BACKGROUND: Existing methods of non-viral airway gene transfer suffer from low levels of efficiency. Electroporation has been used to enhance gene transfer in a range of tissues. Here we assess the usefulness of electroporation for enhancing gene transfer in the lungs of mice and sheep. METHODS: Naked plasmid DNA (pDNA) expressing either luciferase or green fluorescent protein (GFP) was delivered to mouse lungs by instillation. Following surgical visualisation, the lungs were directly electroporated and the level and duration of luciferase activity was assessed and cell types that were positive for GFP were identified in lung cryosections. Naked pDNA was nebulised to the sheep lung and electrodes attached to the tip of a bronchoscope were used to electroporate airway segment bifurcations, Luciferase activity was assessed in electroporated and control non-electroporated regions, after 24 h. RESULTS: Following delivery of naked pDNA to the mouse lung, electroporation resulted in up to 400-fold higher luciferase activity than naked pDNA alone when luciferase was under the control of a cytomegalovirus (CMV) promoter. Following delivery of a plasmid containing the human polyubiquitin C (UbC) promoter, electroporation resulted in elevated luciferase activity for at least 28 days. Visualisation of GFP indicated that electroporation resulted in increased GFP detection compared with non-electroporated controls. In the sheep lung electroporation of defined sites in the airways resulted in luciferase activity 100-fold greater than naked pDNA alone. CONCLUSIONS: These results indicate that electroporation can be used to enhance gene transfer in the lungs of mice and sheep without compromising the duration of expression.

Substrate delivery and ionic balance disturbance after severe human head injury

The most important early pathomechanism in traumatic brain injury (TBI) is alteration of the resting membrane potential. This may be mediated via voltage, or agonist-dependent ion channels (e.g. glutamate-dependent channels). This may result in a consequent increase in metabolism with increased oxygen consumption, in order to try to restore ionic balance via the ATP-dependent pumps. We hypothesize that glutamate is an important agonist in this process and may induce an increase in lactate, potassium and brain tissue CO2, and hence a decrease in brain pH. Further we propose that an increase in lactate is thus not an indicator of anaerobic metabolic conditions as has been thought for many years. We therefore analyzed a total of 85 patients with TBI, Glasgow Coma Scale (GCS) < 8 using microdialysis, brain tissue oxygen, CO2 and pH monitoring. Cerebral blood flow studies (CBF) were performed to test the relationship between regional cerebral blood flow (rCBF) and the metabolic determinants. Glutamate was significantly correlated with lactate (p < 0.0001), potassium (p < 0.0001), brain tissue pH (p = 0.0005), and brain tissue CO2 (p = 0.006). rCBF was inversely correlated with glutamate, lactate and potassium. 44% of high lactate values were observed in brain with tissue oxygen values, above the threshold level for cell damage. These results support the hypothesis of a glutamate driven increase in metabolism, with secondary traumatic depolarization and possibly hyperglycolysis. Further, we demonstrate evidence for lactate production in aerobic conditions in humans after TBI. Finally, when reduced regional cerebral blood flow (rCBF) is observed, high dialysate glutamate, lactate and potassium values are usually seen, suggesting ischemia worsens these TBI-induced changes.

Development of the premature infant nose throat-model (PrINT-Model): an upper airway replica of a premature neonate for the study of aerosol delivery

Clinical efficacy of aerosol therapy in premature newborns depends on the efficiency of delivery of aerosolized drug to the bronchial tree. To study the influence of various anatomical, physical, and physiological factors on aerosol delivery in preterm newborns, it is crucial to have appropriate in vitro models, which are currently not available. We therefore constructed the premature infant nose throat-model (PrINT-Model), an upper airway model corresponding to a premature infant of 32-wk gestational age by three-dimensional (3D) reconstruction of a three-planar magnetic resonance imaging scan and subsequent 3D-printing. Validation was realized by visual comparison and comparison of total airway volume. To study the feasibility of measuring aerosol deposition, budesonide was aerosolized through the cast and lung dose was expressed as percentage of nominal dose. The airway volumes of the initial magnetic resonance imaging and validation computed tomography scan showed a relative deviation of 0.94%. Lung dose at low flow (1 L/min) was 61.84% and 9.00% at high flow (10 L/min), p < 0.0001. 3D-reconstruction provided an anatomically accurate surrogate of the upper airways of a 32-wk-old premature infant, making the model suitable for future in vitro testing.

Strategies to advance translational research into brain barriers

There is a paucity of therapies for most neurological disorders--from rare lysosomal storage diseases to major public health concerns such as stroke and Alzheimer's disease. Advances in the targeting of drugs to the CNS are essential for the future success of neurotherapeutics; however, the delivery of many potentially therapeutic and diagnostic compounds to specific areas of the brain is restricted by the blood-brain barrier, the blood-CSF barrier, or other specialised CNS barriers. These brain barriers are now recognised as a major obstacle to the treatment of most brain disorders. The challenge to deliver therapies to the CNS is formidable, and the solution will require concerted international efforts among academia, government, and industry. At a recent meeting of expert panels, essential and high-priority recommendations to propel brain barrier research forward in six topical areas were developed and these recommendations are presented here.

Esophageal strictures in adult eosinophilic esophagitis: dilation is an effective and safe alternative after failure of topical corticosteroids

Strictures are a frequent complication of eosinophilic esophagitis. The efficacy and safety of topical corticosteroids and of dilation of eosinophilic esophagitis-associated strictures have not yet been thoroughly clarified. We present a retrospective analysis of 10 adult patients with eosinophilic esophagitis who had symptomatic esophageal stenosis that was unresponsive to topical corticosteroids, and who were treated using bougienage. Eight patients had one single stricture, one patient had two, and another had three strictures; mean stricture length was 2.1 cm (range 1 - 6 cm). Bougienage led to prompt symptom relief. Apart from transient postprocedural odynophagia, no severe complications occurred. During the follow-up (mean 6 months; range 2 - 11 months), all patients enjoyed sustained treatment response.

EpCAM-targeted delivery of nanocomplexed siRNA to tumor cells with designed ankyrin repeat proteins

Specific delivery to tumors and efficient cellular uptake of nucleic acids remain major challenges for gene-targeted cancer therapies. Here we report the use of a designed ankyrin repeat protein (DARPin) specific for the epithelial cell adhesion molecule (EpCAM) as a carrier for small interfering RNA (siRNA) complementary to the bcl-2 mRNA. For charge complexation of the siRNA, the DARPin was fused to a truncated human protamine-1 sequence. To increase the cell binding affinity and the amount of siRNA delivered into cells, DARPin dimers were generated and used as fusion proteins with protamine. All proteins expressed well in Escherichia coli in soluble form, yet, to remove tightly bound bacterial nucleic acids, they were purified under denaturing conditions by immobilized metal ion affinity chromatography, followed by refolding. The fusion proteins were capable of complexing four to five siRNA molecules per protamine, and fully retained the binding specificity for EpCAM as shown on MCF-7 breast carcinoma cells. In contrast to unspecific LipofectAMINE transfection, down-regulation of antiapoptotic bcl-2 using fusion protein complexed siRNA was strictly dependent on EpCAM binding and internalization. Inhibition of bcl-2 expression facilitated tumor cell apoptosis as shown by increased sensitivity to the anticancer agent doxorubicin.

Anti-infective therapy of peri-implantitis with adjunctive local drug delivery or photodynamic therapy: 12-month outcomes of a randomized controlled clinical trial

OBJECTIVE: The objective of the study is to compare the clinical, microbiological and host-derived effects in the non-surgical treatment of initial peri-implantitis with either adjunctive local drug delivery (LDD) or adjunctive photodynamic therapy (PDT) after 12 months. MATERIALS AND METHODS: Forty subjects with initial peri-implantitis, that is, pocket probing depths (PPD) 4-6 mm with bleeding on probing (BoP) and radiographic bone loss ≤2 mm, were randomly assigned to two treatment groups. All implants were mechanically debrided with titanium curettes and with a glycine-based powder airpolishing system. Implants in the test group (N = 20) received adjunctive PDT, whereas minocycline microspheres were locally delivered into the peri-implant pockets of control implants (N = 20). At sites with residual BoP, treatment was repeated after 3, 6, 9 and 12 months. The primary outcome variable was the change in the number of peri-implant sites with BoP. Secondary outcome variables included changes in PPD, clinical attachment level (CAL), mucosal recession (REC) and in bacterial counts and crevicular fluid (CF) levels of host-derived biomarkers. RESULTS: After 12 months, the number of BoP-positive sites decreased statistically significantly (P < 0.05) from baseline in both groups (PDT: 4.03 ± 1.66-1.74 ± 1.37, LDD: 4.41 ± 1.47-1.55 ± 1.26). A statistically significant (P < 0.05) decrease in PPD from baseline was observed at PDT-treated sites up to 9 months (4.19 ± 0.55 mm to 3.89 ± 0.68 mm) and up to 12 months at LDD-treated sites (4.39 ± 0.77 mm to 3.83 ± 0.85 mm). Counts of Porphyromonas gingivalis and Tannerella forsythia decreased statistically significantly (P < 0.05) from baseline to 6 months in the PDT and to 12 months in the LDD group, respectively. CF levels of IL-1β decreased statistically significantly (P < 0.05) from baseline to 12 months in both groups. No statistically significant differences (P > 0.05) were observed between groups after 12 months with respect to clinical, microbiological and host-derived parameters. CONCLUSIONS: Non-surgical mechanical debridement with adjunctive PDT was equally effective in the reduction of mucosal inflammation as with adjunctive delivery of minocycline microspheres up to 12 months. Adjunctive PDT may represent an alternative approach to LDD in the non-surgical treatment of initial peri-implantitis.

Nonviral Gene Delivery of Growth and Differentiation Factor 5 to Human Mesenchymal Stem Cells Injected into a 3D Bovine Intervertebral Disc Organ Culture System

Intervertebral disc (IVD) cell therapy with unconditioned 2D expanded mesenchymal stem cells (MSC) is a promising concept yet challenging to realize. Differentiation of MSCs by nonviral gene delivery of growth and differentiation factor 5 (GDF5) by electroporation mediated gene transfer could be an excellent source for cell transplantation. Human MSCs were harvested from bone marrow aspirate and GDF5 gene transfer was achieved by in vitro electroporation. Transfected cells were cultured as monolayers and as 3D cultures in 1.2% alginate bead culture. MSC expressed GDF5 efficiently for up to 21 days. The combination of GDF5 gene transfer and 3D culture in alginate showed an upregulation of aggrecan and SOX9, two markers for chondrogenesis, and KRT19 as a marker for discogenesis compared to untransfected cells. The cells encapsulated in alginate produced more proteoglycans expressed in GAG/DNA ratio. Furthermore, GDF5 transfected MCS injected into an IVD papain degeneration organ culture model showed a partial recovery of the GAG/DNA ratio after 7 days. In this study we demonstrate the potential of GDF5 transfected MSC as a promising approach for clinical translation for disc regeneration.