Effects of sevelamer carbonate versus calcium acetate on vascular calcification, inflammation, and endothelial dysfunction in chronic kidney disease.

Hyperphosphatemia is present in most patients with end-stage renal disease (ESRD) and has been associated with increased cardiovascular mortality. Phosphate binders (calcium-based and calcium free) are the mainstay pharmacologic treatment to lower phosphorus levels in patients with ESRD. We evaluated biochemical markers of vascular calcification, inflammation, and endothelial dysfunction in patients with chronic kidney disease (CKD) treated with sevelamer carbonate (SC) versus calcium acetate (CA). Fifty patients with CKD (stages 3 and 4) were enrolled and assigned to treatment with SC and CA for 12 weeks. At the end of the study the biomarkers of vascular calcification, inflammation, and endothelial dysfunction were analyzed. A significant increase in HDL-cholesterol was observed with SC but not with CA in patients with CKD. Treatment with SC reduced serum phosphate, calcium phosphate, and FGF-23 levels and there was no change with CA treatment. The inflammatory markers IL-8, IFN-γ, and TNFα decreased with response to both treatments. The levels of IL-6 significantly increased with CA treatment and no change was observed in the SC treatment group. SC showed favorable effects on anti-inflammatory and vascular calcification biomarkers compared to CA treatment in patients with CKD stages 3 and 4 with normal phosphorous values.

Fentanyl-induced hyperalgesia and analgesic tolerance in male rats: common underlying mechanisms and prevention by a polyamine deficient diet.

Opioids are a mainstay of pain management but can induce unwanted effects, including analgesic tolerance and paradoxical hyperalgesia, either of which leads to increased pain. Clinically, however, the relationship between these two phenomena remains elusive. By evaluating changes in mechanical nociceptive threshold in male rats, we found that in contrast to a purely analgesic control response to a single subcutaneous administration of fentanyl (25 µg/kg), in rats subjected to inflammatory pain 2 weeks previously (Day0), the same test dose (D13) induced a bi-phasic response: initial decreased analgesia (tolerance) followed by hyperalgesia lasting several hours. Both the tolerance and hyperalgesia were further enhanced in rats that had additionally received fentanyl on D0. The dose-response profiles (5 fg to 50 µg/kg) of pain- and opioid-experienced rats were very different from pain/drug-naive rats. At ultra-low fentanyl doses (<5 ng/kg and <500 ng/kg for naïve control and pain/drug-experienced rats, respectively), solely hyperalgesia was observed in all cases. At higher doses, which now produced analgesia alone in naive rats, reduced analgesia (tolerance) coupled with hyperalgesia occurred in pain/fentanyl-experienced rats, with both phases increasing with dose. Transcriptomic and pharmacological data revealed that an overactivation of the spinal N-methyl-D-aspartate receptor-inducible NO synthase cascade plays a critical role in both acute tolerance and hyperalgesia, and together with the finding that the magnitudes of analgesia and associated hyperalgesia are negatively correlated, is indicative of closely related phenomena. Finally, a polyamine deficient diet prevented inducible NO synthase transcript upregulation, restored fentanyl's analgesic efficacy and suppressed the emergence of hyperalgesia.

Prevention of multiple system atrophy using human bone marrow-derived mesenchymal stem cells by reducing polyamine and cholesterol-induced neural damages.

BACKGROUND: Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder of unknown etiology, but is closely associated with damage to dopaminergic neurons. MSA progression is rapid. Hence, long-term drug treatments do not have any therapeutic benefits. We assessed the inhibitory effect of mesenchymal stem cells (MSCs) on double-toxin-induced dopaminergic neurodegenerative MSA. RESULTS: Behavioral disorder was significantly improved and neurodegeneration was prevented following MSC transplantation. Proteomics revealed lower expression of polyamine modulating factor-binding protein 1 (PMFBP1) and higher expression of 3-hydroxymethyl-3-methylglutaryl-CoA lyase (HMGCL), but these changes were reversed after MSC transplantation. In the in vitro study, the 6-OHDA-induced effects were reversed following co-culture with MSC. However, PMFBP1 knockdown inhibited the recovery effect due to the MSCs. Furthermore, HMGCL expression was decreased following co-culture with MSCs, but treatment with recombinant HMGCL protein inhibited the recovery effects due to MSCs. CONCLUSIONS: These data indicate that MSCs protected against neuronal loss in MSA by reducing polyamine- and cholesterol-induced neural damage.

Dendrimer-grafted bioreducible polycation/DNA multilayered films with low cytotoxicity and high transfection ability.

Controlled release of incorporated foreign DNA from multilayered films plays an important role in surface-mediated gene delivery. Herein, multilayered polyelectrolyte complex thin films, composed of dendrimer-grafted bio-reducible cationic poly(disulfide amine) and plasmid DNA, were fabricated via layer-by-layer (LBL) assembly for in vitro localized gene delivery. The UV absorbance and thickness of the LBL films were found to have linear correlation with the numbers of poly(disulfide amine)/DNA bilayers. Although LBL films were stable in PBS buffer, their degradation could be triggered by reducing agents (i.e. glutathione, GSH). The degradation rate of the films is directly proportional to the GSH concentration, which in turn affected the corresponding gene expression. All poly(disulfide amine)/DNA films exhibited lower cytotoxicity and higher transfection activity in comparison with PEI/DNA multilayered films. Moreover, LBL films showed the highest transfection efficiency in the presence of 2.5 mM GSH when cultured with 293T cells, with ~36% GFP-positive 293T cells after 5-days of co-culture. These DNA-containing reducible films could potentially be useful in gene therapy and tissue engineering by controlling the release of incorporated DNA.

Use of Polyamidoamine Dendrimers in Brain Diseases.

Polyamidoamine (PAMAM) dendrimers are one of the smallest and most precise nanomolecules available today, which have promising applications for the treatment of brain diseases. Each aspect of the dendrimer (core, size or generation, size of cavities, and surface functional groups) can be precisely modulated to yield a variety of nanocarriers for delivery of drugs and genes to brain cells in vitro or in vivo. Two of the most important criteria to consider when using PAMAM dendrimers for neuroscience applications is their safety profile and their potential to be prepared in a reproducible manner. Based on these criteria, features of PAMAM dendrimers are described to help the neuroscience researcher to judiciously choose the right type of dendrimer and the appropriate method for loading the drug to form a safe and effective delivery system to the brain.

Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD).

BACKGROUND: Phosphate binders are used to reduce positive phosphate balance and to lower serum phosphate levels for people with chronic kidney disease (CKD) with the aim to prevent progression of chronic kidney disease-mineral and bone disorder (CKD-MBD). This is an update of a review first published in 2011. OBJECTIVES: The aim of this review was to assess the benefits and harms of phosphate binders for people with CKD with particular reference to relevant biochemical end-points, musculoskeletal and cardiovascular morbidity, hospitalisation, and death. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 12 July 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: We included randomised controlled trials (RCTs) or quasi-RCTs of adults with CKD of any GFR category comparing a phosphate binder to another phosphate binder, placebo or usual care to lower serum phosphate. Outcomes included all-cause and cardiovascular death, myocardial infarction, stroke, adverse events, vascular calcification and bone fracture, and surrogates for such outcomes including serum phosphate, parathyroid hormone (PTH), and FGF23. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of Bias' tool and used the GRADE process to assess evidence certainty. We estimated treatment effects using random-effects meta-analysis. Results were expressed as risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI) or mean differences (MD) or standardised MD (SMD) for continuous outcomes. MAIN RESULTS: We included 104 studies involving 13,744 adults. Sixty-nine new studies were added to this 2018 update.Most placebo or usual care controlled studies were among participants with CKD G2 to G5 not requiring dialysis (15/25 studies involving 1467 participants) while most head to head studies involved participants with CKD G5D treated with dialysis (74/81 studies involving 10,364 participants). Overall, seven studies compared sevelamer with placebo or usual care (667 participants), seven compared lanthanum to placebo or usual care (515 participants), three compared iron to placebo or usual care (422 participants), and four compared calcium to placebo or usual care (278 participants). Thirty studies compared sevelamer to calcium (5424 participants), and fourteen studies compared lanthanum to calcium (1690 participants). No study compared iron-based binders to calcium. The remaining studies evaluated comparisons between sevelamer (hydrochloride or carbonate), sevelamer plus calcium, lanthanum, iron (ferric citrate, sucroferric oxyhydroxide, stabilised polynuclear iron(III)-oxyhydroxide), calcium (acetate, ketoglutarate, carbonate), bixalomer, colestilan, magnesium (carbonate), magnesium plus calcium, aluminium hydroxide, sucralfate, the inhibitor of phosphate absorption nicotinamide, placebo, or usual care without binder. In 82 studies, treatment was evaluated among adults with CKD G5D treated with haemodialysis or peritoneal dialysis, while in 22 studies, treatment was evaluated among participants with CKD G2 to G5. The duration of study follow-up ranged from 8 weeks to 36 months (median 3.7 months). The sample size ranged from 8 to 2103 participants (median 69). The mean age ranged between 42.6 and 68.9 years.Random sequence generation and allocation concealment were low risk in 25 and 15 studies, respectively. Twenty-seven studies reported low risk methods for blinding of participants, investigators, and outcome assessors. Thirty-one studies were at low risk of attrition bias and 69 studies were at low risk of selective reporting bias.In CKD G2 to G5, compared with placebo or usual care, sevelamer, lanthanum, iron and calcium-based phosphate binders had uncertain or inestimable effects on death (all causes), cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification. Sevelamer may lead to constipation (RR 6.92, CI 2.24 to 21.4; low certainty) and lanthanum (RR 2.98, CI 1.21 to 7.30, moderate certainty) and iron-based binders (RR 2.66, CI 1.15 to 6.12, moderate certainty) probably increased constipation compared with placebo or usual care. Lanthanum may result in vomiting (RR 3.72, CI 1.36 to 10.18, low certainty). Iron-based binders probably result in diarrhoea (RR 2.81, CI 1.18 to 6.68, high certainty), while the risks of other adverse events for all binders were uncertain.In CKD G5D sevelamer may lead to lower death (all causes) (RR 0.53, CI 0.30 to 0.91, low certainty) and induce less hypercalcaemia (RR 0.30, CI 0.20 to 0.43, low certainty) when compared with calcium-based binders, and has uncertain or inestimable effects on cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification. The finding of lower death with sevelamer compared with calcium was present when the analysis was restricted to studies at low risk of bias (RR 0.50, CI 0.32 to 0.77). In absolute terms, sevelamer may lower risk of death (all causes) from 210 per 1000 to 105 per 1000 over a follow-up of up to 36 months, compared to calcium-based binders. Compared with calcium-based binders, lanthanum had uncertain effects with respect to all-cause or cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification and probably had reduced risks of treatment-related hypercalcaemia (RR 0.16, CI 0.06 to 0.43, low certainty). There were no head-to-head studies of iron-based binders compared with calcium. The paucity of placebo-controlled studies in CKD G5D has led to uncertainty about the effects of phosphate binders on patient-important outcomes compared with placebo.It is uncertain whether the effects of binders on clinically-relevant outcomes were different for patients who were and were not treated with dialysis in subgroup analyses. AUTHORS' CONCLUSIONS: In studies of adults with CKD G5D treated with dialysis, sevelamer may lower death (all causes) compared to calcium-based binders and incur less treatment-related hypercalcaemia, while we found no clinically important benefits of any phosphate binder on cardiovascular death, myocardial infarction, stroke, fracture or coronary artery calcification. The effects of binders on patient-important outcomes compared to placebo are uncertain. In patients with CKD G2 to G5, the effects of sevelamer, lanthanum, and iron-based phosphate binders on cardiovascular, vascular calcification, and bone outcomes compared to placebo or usual care, are also uncertain and they may incur constipation, while iron-based binders may lead to diarrhoea.

Reducing the Cytotoxicity of Lipid Nanoparticles Associated with a Fusogenic Cationic Lipid in a Natural Killer Cell Line by Introducing a Polycation-Based siRNA Core.

Introducing siRNA into human immune cells by an artificial delivery system continues to be a challenging issue. We previously developed a multifunctional envelope-type nanodevice (MEND) containing the YSK12-C4, a fusogenic cationic lipid, (YSK12-MEND) and succeeded in the efficient delivery of siRNA into human immune cell lines. Significant cytotoxicity, however, was observed at siRNA doses needed for gene silencing in NK-92 cells. NK-92 cells, a unique natural killer (NK) cell line, would be applicable for use in clinical NK therapy. Thus, reducing the cytotoxicity of the YSK12-MEND in NK-92 cells would strengthen the efficacy of NK-92 cell-based therapy. The amount of the YSK12-C4 in the MEND needed to be reduced to reduce the cytotoxicity, because the cytotoxicity was directly associated with the YSK12-C4. In the present study, we decreased the total amount of lipid, including the YSK12-C4, by introducing a core formed by electrostatic interactions of siRNA with a polycation (protamine) (siRNA core), which led to a decrease in cytotoxicity in NK-92 cells. We prepared a YSK12-MEND containing an siRNA core (YSK12-MEND/core) at charge ratios (CR: YSK12-C4/siRNA) of 10, 5, 3, and 2.5 and compared the YSK12-MEND/core with that for a YSK12-MEND (CR16.9). Cell viability was increased by more than 2 times at a CR5 or less. On the other hand, the YSK12-MEND/core (CR5) maintained the same gene silencing efficiency (60%) as the YSK12-MEND. Interestingly, the cellular uptake efficiency and hemolytic activity of the YSK12-MEND/core (CR5) was reduced compared to that for the YSK12-MEND. In calculating the silencing activity per cellular uptake efficiency and hemolytic activity, the value for the YSK12-MEND/core (CR5) was more than 2 times as high as that of the YSK12-MEND. The fact indicates that after endosomal escape, the process can be enhanced by using a YSK12-MEND/core (CR5). Thus, introducing an siRNA core into lipid nanoparticles can be a potent strategy for decreasing cytotoxicity without an appreciable loss of gene silencing activity in NK-92 cells.

Evaluation of the Antimicrobial Activity of Cationic Polymers against Mycobacteria: Toward Antitubercular Macromolecules.

Antimicrobial resistance is a global healthcare problem with a dwindling arsenal of usable drugs. Tuberculosis, caused by Mycobacterium tuberculosis, requires long-term combination therapy and multi- and totally drug resistant strains have emerged. This study reports the antibacterial activity of cationic polymers against mycobacteria, which are distinguished from other Gram-positive bacteria by their unique cell wall comprising a covalently linked mycolic acid-arabinogalactan-peptidoglycan complex (mAGP), interspersed with additional complex lipids which helps them persist in their host. The present study finds that poly(dimethylaminoethyl methacrylate) has particularly potent antimycobacterial activity and high selectivity over two Gram-negative strains. Removal of the backbone methyl group (poly(dimethylaminoethyl acrylate)) decreased antimycobacterial activity, and poly(aminoethyl methacrylate) also had no activity against mycobacteria. Hemolysis assays revealed poly(dimethylaminoethyl methacrylate) did not disrupt red blood cell membranes. Interestingly, poly(dimethylaminoethyl methacrylate) was not found to permeabilize mycobacterial membranes, as judged by dye exclusion assays, suggesting the mode of action is not simple membrane disruption, supported by electron microscopy analysis. These results demonstrate that synthetic polycations, with the correctly tuned structure are useful tools against mycobacterial infections, for which new drugs are urgently required.

Anticancer activity of some polyamine derivatives on human prostate and breast cancer cell lines.

The aim of this study was to expand our knowledge about anticancer activity of some polyamine derivatives with quinoline or chromane as terminal moieties. Tested compounds were evaluated in vitro towards metastatic human prostate adenocarcinoma (PC3), human carcinoma (DU145) and mammary gland adenocarcinoma (MCF7) cell lines. Cell viability was estimated on the basis of mitochondrial metabolic activity using water-soluble tetrazolium WST1 to establish effective concentrations of the tested compounds under experimental conditions. Cytotoxic potential of polyamine derivatives was determined by the measurement of lactate dehydrogenase activity released from damaged cells, changes in mitochondrial membrane potential, the cell cycle distribution analysis and apoptosis assay. It was revealed that the tested polyamine derivatives differed markedly in their antiproliferative activity. Bischromane derivative 5a exhibited a rather cytostatic than cytotoxic effect on the tested cells, whereas quinoline derivative 3a caused changes in cell membrane integrity, inhibited cell cycle progression, as well as induced apoptosis of prostate and breast cancer cells which suggest its potential application in cancer therapy.

Long-Term Safety and Efficacy of Bixalomer in Hyperphosphatemic Patients With Chronic Kidney Disease Not on Dialysis.

Bixalomer, a metal-free, nonabsorbable phosphate binder, is approved in Japan to treat hyperphosphatemia in dialysis patients. Bixalomer is effective and has a favorable safety profile in predialysis patients with hyperphosphatemia. This study examined the long-term effectiveness and safety of bixalomer in predialysis patients with hyperphosphatemia. This was a 48-week, multicenter, open-label, phase 3 study in Japanese predialysis patients with hyperphosphatemia. Patients received bixalomer at an initial dose of 1500 mg/day, which was titrated to a maximum of 7500 mg/day depending on patients' serum phosphorus responses to bixalomer. A total of 105 patients received bixalomer treatment, and 39 completed the study. The most common reason for discontinuation was initiation of dialysis. Mean serum phosphorus concentrations decreased from 5.15 mg/dL at baseline to 4.67 mg/dL at Week 12 and then fluctuated slightly around this level until it reached 4.58 mg/dL at Week 48. The proportion of total patients achieving the target serum phosphorus concentration (≥2.5 to <4.6 mg/dL) increased after treatment to a maximum of 66.2% at Week 20 and subsequently decreased to 51.3% by Week 48. Most adverse events (AEs) occurred in the first 12 weeks of treatment. The incidence of AEs did not increase with long-term treatment. Common AEs reported included nasopharyngitis (29.5%), constipation (19%), and upper respiratory tract inflammation (12.4%). These findings suggest that long-term treatment with bixalomer is effective, well tolerated, and has no new safety concerns. Bixalomer may be an alternative treatment option for the long-term management of hyperphosphatemia in patients with chronic kidney diseases.

Toll-like receptor 2 promiscuity is responsible for the immunostimulatory activity of nucleic acid nanocarriers.

Lipopolyamines (LPAs) are cationic lipids; they interact spontaneously with nucleic acids to form lipoplexes used for gene delivery. The main hurdle to using lipoplexes in gene therapy lies in their immunostimulatory properties, so far attributed to the nucleic acid cargo, while cationic lipids were considered as inert to the immune system. Here we demonstrate for the first time that di-C18 LPAs trigger pro-inflammatory responses through Toll-like receptor 2 (TLR2) activation, and this whether they are bound to nucleic acids or not. Molecular docking experiments suggest potential TLR2 binding modes reminiscent of bacterial lipopeptide sensing. The di-C18 LPAs share the ability of burying their lipid chains in the hydrophobic cavity of TLR2 and, in some cases, TLR1, at the vicinity of the dimerization interface; the cationic headgroups form multiple hydrogen bonds, thus crosslinking TLRs into functional complexes. Unravelling the molecular basis of TLR1 and TLR6-driven heterodimerization upon LPA binding underlines the highly collaborative and promiscuous ligand binding mechanism. The prevalence of non-specific main chain-mediated interactions demonstrates that potentially any saturated LPA currently used or proposed as transfection agent is likely to activate TLR2 during transfection. Hence our study emphasizes the urgent need to test the inflammatory properties of transfection agents and proposes the use of docking analysis as a preliminary screening tool for the synthesis of new non-immunostimulatory nanocarriers.

Self-Assembled Gold Nanoclusters for Bright Fluorescence Imaging and Enhanced Drug Delivery.

Nanoparticles combining enhanced cellular drug delivery with efficient fluorescence detection are important tools for the development of theranostic agents. Here, we demonstrate this concept by a simple, fast, and robust protocol of cationic polymer-mediated gold nanocluster (Au NCs) self-assembly into nanoparticles (NPs) of ca. 120 nm diameter. An extensive characterization of the monodisperse and positively charged NPs revealed pH-dependent swelling properties, strong fluorescence enhancement, and excellent colloidal and photostability in water, buffer, and culture medium. The versatility of the preparation is demonstrated by using different Au NC surface ligands and cationic polymers. Steady-state and time-resolved fluorescence measurements give insight into the aggregation-induced emission phenomenon (AIE) by tuning the Au NC interactions in the self-assembled nanoparticles using the pH-dependent swelling. In vitro studies in human monocytic cells indicate strongly enhanced uptake of the NPs compared to free Au NCs in endocytic compartments. The NPs keep their assembly structure with quite low cytotoxicity up to 500 µg Au/mL. Enhanced drug delivery is demonstrated by loading peptides or antibodies in the NPs using a one-pot synthesis. Fluorescence microscopy and flow cytometry confirmed intracellular colocalization of the biomolecules and the NP carriers with a respective 1.7-fold and 6.5-fold enhanced cellular uptake of peptides and antibodies compared to the free biomolecules.

Dietary polyamine intake and colorectal cancer risk in postmenopausal women.

BACKGROUND: Putrescine, spermidine, and spermine (i.e., polyamines) are small cationic amines synthesized by cells or acquired from the diet or gut bacteria. Polyamines are required for both normal and colorectal cancer (CRC) cell growth. OBJECTIVE: We investigated the association between dietary polyamines and risk of CRC incidence and mortality. DESIGN: The study was a prospective analysis in 87,602 postmenopausal women in the Women's Health Initiative Observational Study. Multivariate Cox regression was used to calculate HRs and 95% CIs. RESULTS: Total dietary polyamine intake (mean ± SD: 289.2 ± 127.4 µmol/d) was not positively associated with CRC in fully adjusted models. Instead, intake ≥179.67 µmol/d was associated with reduced risk of CRC [HR (95% CI): 0.82 (0.68, 1.00), 0.81 (0.66, 0.99), 0.91 (0.74, 1.12), and 0.80 (0.62, 1.02) for quintiles 2-5, respectively, compared with quintile 1]. Reduced risk was not significant across all quintiles. Polyamines were not significantly associated with CRC-specific mortality in fully adjusted models. When stratified by risk factors for CRC, only body mass index (BMI) and fiber intake significantly modified the association between polyamine intake and CRC. In women with BMI (in kg/m²) ≤25 or fiber consumption above the median, polyamine intake was associated with significantly lower risk of CRC. CONCLUSIONS: No positive association between dietary polyamines and CRC or CRC-specific mortality risk in women was observed. Instead, a protective effect of dietary polyamines was suggested in women with some CRC risk-lowering behaviors in particular. These results are consistent with emerging evidence that exogenous polyamines may be beneficial in colon health and warrant additional study.

Anti-Biofilm Efficacy of Dual-Action Nitric Oxide-Releasing Alkyl Chain Modified Poly(amidoamine) Dendrimers.

Herein, we describe the synthesis of nitric oxide (NO)-releasing alkyl chain modified poly(amidoamine) (PAMAM) dendrimers of various sizes (i.e., generations). Generation 1 (G1) through generation 4 (G4) dendrimers were modified with either short (i.e., butyl) or medium (i.e., hexyl) alkyl chains via a ring-opening reaction. The resulting secondary amines were subsequently modified with N-diazeniumdiolate NO donors to establish NO payloads of ∼1.0 µmol/mg. The bactericidal efficacy of these dendrimers was evaluated against Gram-negative and Gram-positive biofilms, including antibiotic-resistant strains. The anti-biofilm action of the dendrimer biocides was found to be dependent on dendrimer generation, bacterial Gram class, and alkyl chain length, with the most effective biofilm eradication occurring when antibacterial agents were capable of efficient biofilm infiltration. The addition of NO release markedly enhanced anti-biofilm activity of dendrimers incapable of effective biofilm penetration.

A simple approach for producing highly efficient DNA carriers with reduced toxicity based on modified polyallylamine.

Nowadays gene delivery is a topic in many research studies. Non-viral vectors have many advantages over viral vectors in terms of safety, immunogenicity and gene carrying capacity but they suffer from low transfection efficiency and high toxicity. In this study, polyallylamine (PAA), the cationic polymer, has been modified with hydrophobic branches to increase the transfection efficiency of the polymer. Polyallylamine with molecular weights of 15 and 65kDa was selected and grafted with butyl, hexyl and decyl acrylate at percentages of 10, 30 and 50. The ability of the modified polymer to condense DNA was examined by ethidium bromide test. The complex of modified polymer and DNA (polyplex) was characterized for size, zeta potential, transfection efficiency and cytotoxicity in Neuro2A cell lines. The results of ethidium bromide test showed that grafting of PAA decreased its ability for DNA condensation but vectors could still condense DNA at moderate and high carrier to DNA ratios. Most of polyplexes had particle size between 150 and 250nm. The prepared vectors mainly showed positive zeta potential but carriers composed of PAA with high percentage of grafting had negative zeta potential. The best transfection activity was observed in vectors with hexyl acrylate chain. Grafting of polymer reduced its cytotoxicity especially at percentages of 30 and 50. The vectors based of PAA 15kDa had better transfection efficiency than the vectors made of PAA 65kDa. In conclusion, results of the present study indicated that grafting PAA 15kDa with high percentages of hexyl acrylate can help to prepare vectors with better transfection efficiency and less cytotoxicity.

Development of surface modified biodegradable polymeric nanoparticles to deliver GSE24.2 peptide to cells: a promising approach for the treatment of defective telomerase disorders.

The aim of the present study was to develop a novel strategy to deliver intracellularly the peptide GSE24.2 for the treatment of Dyskeratosis congenita (DC) and other defective telomerase disorders. For this purpose, biodegradable polymeric nanoparticles using poly(lactic-co-glycolic acid) (PLGA NPs) or poly(lactic-co-glycolic acid)-poly ethylene glycol (PLGA-PEG NPs) attached to either polycations or cell-penetrating peptides (CPPs) were prepared in order to increase their cellular uptake. The particles exhibited an adequate size and zeta potential, with good peptide loading and a biphasic pattern obtained in the in vitro release assay, showing an initial burst release and a later sustained release. GSE24.2 structural integrity after encapsulation was assessed using SDS-PAGE, revealing an unaltered peptide after the NPs elaboration. According to the cytotoxicity results, cell viability was not affected by uncoated polymeric NPs, but the incorporation of surface modifiers slightly decreased the viability of cells. The intracellular uptake exhibited a remarkable improvement of the internalization, when the NPs were conjugated to the CPPs. Finally, the bioactivity, addressed by measuring DNA damage rescue and telomerase reactivation, showed that some formulations had the lowest cytotoxicity and highest biological activity. These results proved that GSE24.2-loaded NPs could be delivered to cells, and therefore, become an effective approach for the treatment of DC and other defective telomerase syndromes.

PAMAM dendrimers: destined for success or doomed to fail? Plain and modified PAMAM dendrimers in the context of biomedical applications.

PAMAM (polyamidoamine) dendrimers are commonly considered promising polymers that can be successfully used in various biomedical applications. Nevertheless, direct clinical adaptations of plain unmodified PAMAM dendrimers may be limited at present, mainly because of their toxicity, unpredictable behavior in living organisms, unknown bioavailability, biocompatibility or pharmacokinetic profile, problematic therapeutic dose selection, or high cost of production. On the basis of our studies concerning the possible use of unmodified PAMAM dendrimers as the scavengers of glucose and carbonyl stress in animal models of human pathology, as well as considering available literature on experimental data of other researchers, we have prepared the brief critical review of the biomedical activities of these unmodified compounds and their most alluring derivatives, especially in the context of possible future perspectives of PAMAMs. Thus, on the pages of this review, we made an attempt to briefly summarize obstacles, emerging from experimental, technical, and human limitations, that may, to some extent, restrain our belief in a brighter future of plain amine-terminated PAMAM dendrimers.

Sevelamer carbonate markedly reduces levothyroxine absorption.

We report the case of a young woman affected by hypothyroidism due to Hashimoto's thyroiditis, previously well compensated with a full replacement therapy (150 mcg/day of levothyroxine), presenting a clinical picture of myxedema, with a TSH=650 mU/L. Two years earlier she had started a dialysis treatment because of a chronic renal failure and had been under treatment for the last 18 months with sevelamer carbonate, a phosphate binder. No improvement of clinical conditions nor reduction in TSH serum levels was observed even on increasing the dose of levothyroxine up to 300 mcg/day, whereas euthyroidism finally restored by administering the first morning dose of sevelamer carbonate at least 4 hours after levothyroxine administration. This case shows that sevelamer carbonate, in analogy with what has been already reported for sevelamer hydrochloride, can interfere with levothyroxine absorption leading to a condition of hypothyroidism in patients previously well compensated with a given replacement dose.

Contact allergy to epoxy hardeners.

BACKGROUND: Diglycidylether of bisphenol A resin is the most important sensitizer in epoxy systems, but a minority of patients develop concomitant or solitary contact allergy to epoxy hardeners. At the Finnish Institute of Occupational Health, several in-house test substances of epoxy hardeners have been tested in a special epoxy compound patch test series. OBJECTIVES: To analyse the frequency and clinical relevance of allergic reactions to different epoxy hardeners. METHODS: Test files (January 1991 to March 2013) were screened for contact allergy to different epoxy hardeners, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. RESULTS: The most commonly positive epoxy hardeners were m-xylylenediamine (n = 24), 2,4,6-tris-(dimethylaminomethyl)phenol (tris-DMP; n = 14), isophorone-diamine (n = 12), and diethylenetriamine (n = 9). Trimethylhexamethylenediamine (n = 7), tetraethylenepentamine (n = 4), and triethylenetetramine (n = 2) elicited some reactions, although most patients were found to have no specific exposure. Allergic reactions to hexamethylenetetramine, dimethylaminopropylamine and ethylenediamine dihydrochloride were not related to epoxy products. CONCLUSIONS: Tris-DMP is an important sensitizer in epoxy hardeners, and should be included in the patch test series of epoxy chemicals.