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The aim of the study was to examine the reproducibility of a rat model to assess the preclinical similarity in safety profiles and tissue accumulation of iron products. Accordingly, the effect of several doses of intravenously administered Venofer® and of Ferrlecit® on blood parameters, and on kidney and particularly liver toxicity were examined in non-anemic Sprague Dawley rats. The different analysis showed neither a clear treatment nor a dose effect after multiple injections. The parameters measured in this rat strain showed some iron induced adverse effects, but these could not be correlated to treatment specific differences. The findings presented in this paper indicate the difficulty to define a useful preclinical model to evaluate iron-based nano-colloidal preparations.

Objective: Implanted neuromodulation devices are known to interact with ECG-recordings. This has been reported as for DBS, SCS, as well as baroreceptor cell stimulation patients. In cardiac emergencies, interpretation of heart rate, rhythm, or even ST-segment can be completely impeded preventing emergency[for full text, please go to the a.m. URL], 69. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Mexikanischen und Kolumbianischen Gesellschaft für Neurochirurgie

Purpose: The aim of this study was to determine the potential of magnetic resonance imaging to evaluate the biodistribution of exogenous iron within 24 h after one single injection of Venofer® (iron sucrose). Methods: Venofer® was evaluated in vitro for its ability to generate contrast in MR images. Subsequently, iron disposition was assessed in rats with MRI, in vivo up to 3 h and post mortem at 24 h after injection of Venofer®, at doses of 10- and 40 mg/kg body weight (n = 2 × 4), or saline (n = 4). Results: Within 10–20 min after injection of Venofer®, transverse relaxation rates (R2) clearly increased, representative of a local increase in iron concentration, in liver, spleen and kidney, including the kidney medulla and cortex. In liver and spleen R2 values remained elevated up to 3 h post injection, while the initial R2 increase in the kidney was followed by gradual decrease towards baseline levels. Bone marrow and muscle tissue did not show significant increases in R2 values. Whole-body post mortem MRI showed most prominent iron accumulation in the liver and spleen at 24 h post injection, which corroborated the in vivo results. Conclusions: MR imaging is a powerful imaging modality for non-invasive assessment of iron distribution in organs. It is recommended to use this whole-body imaging approach complementary to other techniques that allow quantification of iron disposition at a (sub)cellular level.

The clinical efficacy of epidermal growth factor receptor (EGFR)-targeted inhibitors is limited due to resistance mechanisms of the tumor such as activation of compensatory pathways. Crosstalk between EGFR and insulin-like growth factor 1 (IGF-1R) signaling has been frequently described to be involved in tumor proliferation and resistance. One of the attractive features of nanomedicines is the possibility to codeliver agents that inhibit different molecular targets in one nanocarrier system, thereby strengthening the antitumor effects of the individual agents. Additionally, exposure to healthy tissues and related unwanted side-effects can be reduced. To this end, we have recently developed anti-EGFR nanobody (Nb)-liposomes loaded with the anti-IGF-1R kinase inhibitor AG538, which showed promising antiproliferative effects in vitro. In the present study, we have further evaluated the potential of this dual-active nanomedicine in vitro and for the first time in vivo. As intended, the nanomedicine inhibited EGFR and IGF-1R signaling and subsequent activation of downstream cell proliferation and survival pathways. The degree of inhibition induced by the nanomedicine on a molecular level correlated with cytotoxicity in tumor cell proliferation assays and may even be predictive of the response to nanomedicine treatment in tumor xenograft models. Combination therapy with kinase inhibitor-loaded Nb-liposomes is therefore an appealing strategy for inhibiting the proliferation of tumors that are highly dependent on EGFR and IGF-1R signaling.

Various different passively and actively targeted nanomedicines have been designed and evaluated over the years, in particular for the treatment of cancer. Reasoning that the potential of ligand-modified nanomedicines can be substantially improved if intrinsically active targeting moieties are used, we have here set out to assess the in vivo efficacy of nanobody-modified core-crosslinked polymeric micelles containing covalently entrapped doxorubicin. Nanobody-modified polymeric micelles were found to inhibit tumor growth even in the absence of a drug, and nanobody-modified micelles containing doxorubicin were significantly more effective than nanobody-free micelles containing doxorubicin. Based on these findings, we propose that the combination of two therapeutic strategies within one nanomedicine formulation, i.e. the intrinsic pharmacological activity of ligand-modified carrier materials with the cytostatic activity of the incorporated chemotherapeutic agents, is a highly promising approach for improving the efficacy of tumor-targeted combination therapy.

Cancer vaccines are at present mostly based on tumor associated protein antigens but fail to elicit strong cell-mediated immunity in their free form. For protein-based vaccines, the main challenges to overcome are the delivery of sufficient proteins into the cytosol of dendritic cells (DCs) and processing by, and presentation through, the MHC class I pathway. Recently, we developed a cationic dextran nanogel in which a model antigen (ovalbumin, OVA) is reversibly conjugated via disulfide bonds to the nanogel network to enable redox-sensitive intracellular release. In the present study, it is demonstrated that these nanogels, with the bound OVA, were efficiently internalized by DCs and were capable of maturating them. On the other hand, when the antigen was just physically entrapped in the nanogels, OVA was prematurely released before the particles were taken up by cells. When combined with an adjuvant (polyinosinic-polycytidylic acid, poly(I:C)), nanogels with conjugated OVA induced a strong protective and curative effect against melanoma in vivo. In a prophylactic vaccination setting, 90% of the mice vaccinated with nanogels with conjugated OVA + poly(I:C) did not develop a tumor. Moreover, in a therapeutic model, 40% of the mice showed clearance of established tumors and survived for the duration of the experiment (80 days) while the remaining mice showed substantial delay in tumor progression. In conclusion, our results demonstrate that conjugation of antigens to nanogels via reducible covalent bonds for intracellular delivery is a promising strategy to induce effective antigen-specific immune responses against cancer.

The anticancer drug imatinib is an inhibitor of the platelet-derived growth factor receptor (PDGFR) kinases, which are involved in the pathogenesis of fibrotic diseases. In the current study we investigated the delivery of imatinib to the proximal tubular cells of the kidneys and evaluated the potential antifibrotic effects of imatinib in tubulointerstitial fibrosis. Coupling of imatinib to the low molecular weight protein lysozyme via the platinum (II)-based linker ULS yielded a 0.8:1 drug-carrier conjugate that rapidly accumulated in the proximal tubular cells upon intravenous and intraperitoneal administration. The bioavailability of intraperitoneally administered imatinib-ULS-lysozyme was 100%. Renal imatinib levels persisted for up to 3 days after a single injection of imatinib-ULS-lysozyme. Compared with an equal dose imatinib mesylate, imatinib-ULS-lysozyme resulted in a 30- and 15-fold higher renal exposure of imatinib, for intravenous and intraperitoneal administration respectively. Imatinib-ULS-lysozyme could not be detected in the heart, which is the organ at risk for side-effects of prolonged treatment with imatinib. The efficacy of imatinib-ULS-lysozyme in the treatment of tubulointerstitial fibrosis was evaluated in the unilateral ureteral obstruction (UUO) model in mice. Three days UUO resulted in all signs of early fibrosis, i.e. an increased deposition of matrix and production of profibrotic factors. Although a moderately increased activity of PDGFR-β was observed, the profibrotic phenotype could not be inhibited with imatinib mesylate or with imatinib-ULS-lysozyme. Further evaluation of imatinib mesylate and imatinib-ULS-lysozyme is therefore warranted in an animal model of renal disease in which the activation of PDGFR-β is more pronounced.

Inflammation is an important component of various cancers and its inflammatory cells and mediators have been shown to have prognostic potential. Tumor-infiltrating mast cells can promote tumor growth and angiogenesis, but the mechanism of mast cell activation is unclear. In earlier studies, we demonstrated that immunoglobulin free light chains (FLC) can trigger mast cells in an antigen-specific manner. Increased expression of FLC was observed within stroma of various human cancers including those of breast, colon, lung, pancreas, kidney and skin, and FLC expression co-localized with areas of mast cell infiltration. In a large cohort of breast cancer patients, FLC expression was shown associated with basal-like cancers with an aggressive phenotype. Moreover, lambda FLC was found expressed in areas of inflammatory infiltration and its expression was significantly associated with poor clinical outcome. Functional importance of FLCs was shown in a murine B16F10 melanoma model, where inhibition of FLC-mediated mast cell activation strongly reduced tumor growth. Collectively, this study identifies FLCs as a ligand in the pro-tumorigenic activation of mast cells. Blocking this pathway may open new avenues for the inhibition of tumor growth, while immunohistochemical staining of FLC may be helpful in the diagnosis and prognosis of cancer.

Angiogenesis, the sprouting of new blood vessels from the pre-existing vasculature, is a well established target in anti-cancer therapy. It is thought that the Rho GTPase Rac1 is required during vascular endothelial growth factor (VEGF)-mediated angiogenesis. In the present study, we have used a clinically relevant RNA interference approach to silence Rac1 expression. Human umbilical vein endothelial cells were transiently transfected with non-specific control siRNA (siNS) or Rac1 siRNA (siRac1) using electroporation or Lipofectamine 2000. Functional assays with transfected endothelial cells were performed to determine the effect of Rac1 knockdown on angiogenesis in vitro. Silencing of Rac1 inhibited VEGF-mediated tube formation, cell migration, invasion and proliferation. In addition, treatment with Rac1 siRNA inhibited angiogenesis in an in vivo Matrigel plug assay. Intratumoral injections of siRac1 almost completely inhibited the growth of grafted Neuro2a tumors and reduced tumor angiogenesis. Together, these data indicate that Rac1 is an important regulator of VEGF-mediated angiogenesis. Knockdown of Rac1 may represent an attractive approach to inhibit tumor angiogenesis and growth.

The development of a macromolecular conjugate of a multitargeted tyrosine kinase inhibitor is described that can be used for renal-specific delivery into proximal tubular cells. A novel sunitinib analogue, that is, 17864, is conjugated to a NH(2) -PAMAM-G3 dendrimer via the platinum (II)-based Universal Linkage System (ULS™). The activity of 17864 is retained after coordination to the ULS linker alone or when coupled to NH(2) -PAMAM-G3. 17864-UlS-NH(2) -PAMAM-G3 is non-toxic to proximal tubular cells in vitro. After intravenous administration to mice, 17864-UlS-NH(2) -PAMAM-G3 rapidly and efficiently accumulates in the kidneys. These results are encouraging for future studies focusing on the development of novel therapeutics for the treatment of renal diseases.

Perazin is a piperazine derivative of phenothiazine with higher affinity for the D2 than the D1 receptor. We observed a 43-year-old woman who developed blepharospasm and oral hyperkinesia as a tardive dystonic syndrome after short-term treatment with perazin. She had never taken any other neuroleptic medication and all known forms of secondary dystonia were ruled out. We were unable to find any previous reports of perazin-induced tardive dystonia.

Quantitative measurements of 99MTc-tin colloid uptake in renal transplants permits differentiation of acute rejection from other causes of deteriorating renal function, such as acute tubular necrosis, cyclosporin A nephrotoxicity or chronic rejection. 144 99mTc-tin colloid scintigrams were performed on 71 renal transplants; the results were compared with clinical, biochemical and histological findings. Sensitivity of colloid scintigraphy is 97.4% and specificity is 80%. Compared with other isotope methods, this has the advantage that it does not depend on comparison with repeated examinations.

Tumor-angiogenesis is the multi-factorial process of sprouting of endothelial cells (EC) into micro-vessels to provide tumor cells with nutrients and oxygen. To explore miRNAs as therapeutic angiogenesis-inhibitors, we performed a functional screen to identify miRNAs that are able to decrease EC viability. We identified miRNA-7 (miR-7) as a potent negative regulator of angiogenesis. Introduction of miR-7 in EC resulted in strongly reduced cell viability, tube formation, sprouting and migration. Application of miR-7 in the chick chorioallantoic membrane assay led to a profound reduction of vascularization, similar to anti-angiogenic drug sunitinib. Local administration of miR-7 in an in vivo murine neuroblastoma tumor model significantly inhibited angiogenesis and tumor growth. Finally, systemic administration of miR-7 using a novel integrin-targeted biodegradable polymeric nanoparticles that targets both EC and tumor cells, strongly reduced angiogenesis and tumor proliferation in mice with human glioblastoma xenografts. Transcriptome analysis of miR-7 transfected EC in combination with in silico target prediction resulted in the identification of OGT as novel target gene of miR-7. Our study provides a comprehensive validation of miR-7 as novel anti-angiogenic therapeutic miRNA that can be systemically delivered to both EC and tumor cells and offers promise for miR-7 as novel anti-tumor therapeutic.

ME (Emmy) M Dolman1, Stefan Harmsen1, Ebel HE Pieters1, Rolf W Sparidans2, Marie Lacombe3, Bálint Szokol4, László Orfi4, György Kéri4, Gert Storm1, Wim E Hennink1, Robbert J Kok11Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands; 2Faculty of Science, Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands; 3Kreatech Biotechnology BV, Amsterdam, The Netherlands; 4Vichem Chemie Ltd, Budapest, HungaryBackground: Activated proximal tubular cells play an important role in renal fibrosis. We investigated whether sunitinib and a kidney-targeted conjugate of sunitinib were capable of attenuating fibrogenic events in tubulointerstitial fibrosis.Methods: A kidney-targeted conjugate was prepared by linkage of a sunitinib analog (named 17864) via a platinum-based linker to the kidney-specific carrier lysozyme. Pharmacological activity of 17864-lysozyme was evaluated in human kidney proximal tubular cells (HK-2); the capability of the kidney-directed conjugate to accumulate in the kidneys was studied in mice. Potential antifibrotic effects of a single-dose treatment were evaluated in the unilateral ureteral obstruction (UUO) model in mice.Results: The 17864-lysozyme conjugate and its metabolites strongly inhibited tyrosine kinase activity. Upon intravenous injection, 17864-lysozyme rapidly accumulated in the kidneys and provided sustained renal drug levels for up to 3 days after a single dose. Renal drug level area under the curve was increased 28-fold versus an equimolar dose of sunitinib malate. Daily treatment of UUO mice with a high dose of sunitinib malate (50 mg/kg) resulted in antifibrotic responses, but also induced drug-related toxicity. A single dose of 17864-lysozyme (equivalent to 1.8 mg/kg sunitinib) was safe but showed no antifibrotic effects.Conclusion: Multikinase inhibitors like sunitinib can be of benefit in the treatment of fibrotic diseases, provided that their safety can be improved by strategies as presented in this paper, and sustained renal levels can be achieved.Keywords: drug delivery, sunitinib, fibrosis, platinum linker