Non-Linear Association of Dietary Polyamines with the Risk of Incident Dementia: Results from Population-Based Cohort of the UK Biobank.

Natural polyamines, including spermidine (SPD), spermine (SPM) and putrescine (PUT), are evolutionarily conserved endogenous molecules crucially involved in central cellular processes. Their physiological importance may extend to the maintenance of cognitive function during aging. However, limited population-based epidemiological studies have explored the link between dietary polyamines and dementia risk. This study was a prospective analysis of 77,092 UK Biobank participants aged ≥ 60 years without dementia at baseline. We used Cox proportional hazard regression models to explore the associations between dietary polyamines and the risk of dementia, and restricted cubic splines to test the non-linear relationships. During a median follow-up of 12 years, 1087 incidents of all-cause dementia cases occurred, including 450 Alzheimer's disease (AD) cases and 206 vascular dementia (VD) cases. The fully adjusted hazard ratios (HRs) for the upper fourth quintile of dietary SPD, in comparison with the lowest quintile of intake, were 0.68 (95% confidence interval [95% CI]: 0.66-0.83) for the risk of all-cause dementia, 0.62 (95% CI: 0.45-0.85) for AD and 0.56 (95% CI: 0.36-0.88) for VD, respectively. A 26% reduction in dementia risk [HR: 0.74, (95% CI: 0.61-0.89)] and a 47% reduction in AD [HR: 0.53, (95%CI: 0.39-0.72)] were observed comparing the third with the lowest quintiles of dietary SPM. Dietary PUT was only associated with a reduced risk of all-cause dementia in the fourth quintile [HR (95% CI): 0.82 (0.68-0.99)]. Reduced risk was not found to be significant across all quintiles. There were 'U'-shaped relationships found between dietary polyamines and all-cause dementia, AD and VD. Stratification by genetic predisposition showed no significant effect modification. Optimal intake of polyamines was linked to a decreased risk of dementia, with no modification by genetic risk. This potentially suggests cognitive benefits of dietary natural polyamines in humans.

Delivery of doxorubicin loaded P18 conjugated-poly(2-ethyl-oxazoline)-DOPE nanoliposomes for targeted therapy of breast cancer.

Breast cancer, a heterogeneous disease, has the highest incidence rate and is a major cause of death in females worldwide. Drug delivery by using nanotechnology has shown great promise for improving cancer treatment. Nanoliposomes are known to have enhanced accumulation ability in tumors due to prolonged systemic circulation. Peptide 18 (P18), a tumor homing peptide targeting keratin-1 (KRT-1), was previously shown to have high binding affinity towards breast cancer cells. In this study, we investigate the ability of P18 conjugated PEtOx-DOPE nanoliposomes (P18-PEtOx-DOPE) for the targeted delivery of doxorubicin to AU565 breast cancer model. Toxicology studies of PEtOx-DOPE nanoliposomes performed on normal breast epithelial cells (MCF10A), showed minimal toxicity. Doxorubicin delivery by P18-PEtOx-DOPE to AU565 cells induces cytotoxicity in a dose and time dependent manner causing mitotic arrest in G2/M phase at 24 h. Anti-cancer activity of P18-PEtOx-DOPE-DOX nanoliposomes on AU565 cells was detected by Annexin V/PI apoptosis assay. In terms of in vivo antitumor efficacy, P18-PEtOx-DOPE-DOX nanoliposomes administration to AU565 CD-1 nu/nu mice model showed significant decrease in tumor volume suggesting that DOX delivered by these nanoliposomes elicited a strong antitumor response comparable to the free delivery of doxorubicin. Overall, our results offered preclinical proof for the use of P18-PEtOx-DOPE-DOX nanoliposomes in KRT-1+ breast cancer therapy.

Antibacterial activity of nitric oxide-releasing carboxymethylcellulose against periodontal pathogens.

The prevalence of periodontal disease poses a significant global health burden. Treatments for these diseases, primarily focused on removal and eradication of dental plaque biofilms, are challenging due to limited access to periodontal pockets where these oral pathogens reside. Herein, we report on the development and characterization of nitric oxide (NO)-releasing carboxymethylcellulose (CMC) derivatives and evaluate their in vitro bactericidal efficacy against planktonic Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, two prominent periodontopathogens. Bactericidal exposure assays revealed that three of the synthesized NO-releasing polymers were capable of reducing bacterial viability of both species by 99.9% in 2 hr at concentrations of 4 mg ml-1 or lower, reflecting NO's potent and rapid bactericidal action. The NO-releasing CMCs elicited minimal toxicity to human gingival fibroblasts at their bactericidal concentrations following 24-hr exposure.

Enhanced PCO prevention of drug eluting IOLs via endocytosis and autophagy effects of a PAMAM dendrimer.

Drug-loaded intraocular lenses (IOLs) have received considerable attention in treating complications that arise after cataract surgery, especially posterior capsular opacification (PCO). However, for a better therapeutic effect, the drug concentration in IOLs usually needs to be increased. Herein, we developed multilayer (doxorubicin (DOX)@polyaminoamide (PAMAM) (D@P)/heparin sodium (HEP))5 modified IOLs, which efficiently enhance the inhibitory effect on PCO using the enhanced autophagy effect of a cationic PAMAM. The chemotherapeutic drug DOX was encapsulated in PAMAM to formulate cationic DOX@PAMAM nanoparticles. Subsequently, negatively charged HEP and D@P nanoparticles (NPs) were assembled on the aminated artificial IOL surface using the layer-by-layer (LBL) assembly technique. The (D@P/HEP)5 IOLs were implanted into rabbit eyes to evaluate the prevention of PCO. In vitro and in vivo research studies showed that the D@P NPs exhibited enhanced cellular uptake owing to the cell-penetrating cationic characteristics, while demonstrating enhanced autophagy. D@P NPs are more effective at the same DOX concentration when compared to free DOX. Multilayer-modified (D@P/HEP)5 IOLs can efficiently inhibit PCO after cataract surgery. This study provides a strategy for improving the therapeutic effect of antiproliferative drug DOX by using a cationic dendrimer, which, in turn, increases the level of autophagy of cells. These LBL-based multilayer IOLs have broad application prospects in the treatment of complications after cataract surgery.

Lipodendriplexes mediated enhanced gene delivery: a cellular to pre-clinical investigation.

Clinical success of effective gene therapy is mainly hampered by the insufficiency of safe and efficient internalization of a transgene to the targeted cellular site. Therefore, the development of a safe and efficient nanocarrier system is one of the fundamental challenges to transfer the therapeutic genes to the diseased cells. Polyamidoamine (PAMAM) dendrimer has been used as an efficient non-viral gene vector (dendriplexes) but the toxicity and unusual biodistribution induced by the terminal amino groups (-NH2) limit its in vivo applications. Hence, a state of the art lipid modification with PAMAM based gene carrier (lipodendriplexes) was planned to investigate theirs in vitro (2D and 3D cell culture) and in vivo behaviour. In vitro pDNA transfection, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) generation, cellular protein contents, live/dead staining and apoptosis were studied in 2D cell culture of HEK-293 cells while GFP transfection, 3D cell viability and live/dead staining of spheroids were performed in its 3D cell culture. Acute toxicity studies including organ to body index ratio, hematological parameters, serum biochemistry, histopathological profiles and in vivo transgene expression were assessed in female BALB/c mice. The results suggested that, in comparison to dendriplexes the lipodendriplexes exhibited significant improvement of pDNA transfection (p < 0.001) with lower LDH release (p < 0.01) and ROS generation (p < 0.05). A substantially higher cellular protein content (p < 0.01) and cell viability were also observed in 2D culture. A strong GFP expression with an improved cell viability profile (p < 0.05) was indicated in lipodendriplexes treated 3D spheroids. In vivo archives showed the superiority of lipid-modified nanocarrier system, depicted a significant increase in green fluorescent protein (GFP) expression in the lungs (p < 0.01), heart (p < 0.001), liver (p < 0.001) and kidneys (p < 0.001) with improved serum biochemistry and hematological profile as compared to unmodified dendriplexes. No tissue necrosis was evident in the animal groups treated with lipid-shielded molecules. Therefore, a non-covalent conjugation of lipids with PAMAM based carrier system could be considered as a promising approach for an efficient and biocompatible gene delivery system.

Dietary Polyamines Intake and Risk of Colorectal Cancer: A Case-Control Study.

Polyamines (including putrescine, spermidine, and spermine) are small, cationic molecules that are necessary for cell proliferation and differentiation. Few studies have examined the association of dietary polyamines intake with colorectal cancer risk. The aim of this study was to evaluate total polyamines, putrescine, spermidine, and spermine intake in relation to colorectal cancer risk in China. In total, 2502 colorectal cancer cases and 2538 age-(5-year interval) and sex-matched controls were recruited from July 2010 to April 2019. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated by multivariable unconditional logistic regression after adjustment for various potential confounding factors. Higher intake of total polyamine, putrescine and spermidine was significantly associated with reduced risk of colorectal cancer. The adjusted ORs for the highest compared with the lowest quartile of intake were 0.60 (95% CI 0.50, 0.72; Ptrend < 0.001) for total polyamines, 0.35 (95% CI 0.29, 0.43; Ptrend < 0.001) for putrescine and 0.79 (95% CI 0.66, 0.95; Ptrend = 0.001) for spermidine, respectively. However, higher intake of spermine was associated with increased risk of colorectal cancer, with an adjusted OR of 1.58 (95% CI 1.29, 1.93; Ptrend < 0.001). This data indicate that higher intake of total polyamines, putrescine and spermidine, as well as lower intake of spermine, is associated with a decreased risk of colorectal cancer.

Nanotoxicology of Dendrimers in the Mammalian Heart: ex vivo and in vivo Administration of G6 PAMAM Nanoparticles Impairs Recovery of Cardiac Function Following Ischemia-Reperfusion Injury.

AIM: The effects of polyamidoamine (PAMAM) dendrimers on the mammalian heart are not completely understood. In this study, we have investigated the effects of a sixth-generation cationic dendrimer (G6 PAMAM) on cardiac function in control and diabetic rat hearts following ischemia-reperfusion (I/R) injury. METHODS: Isolated hearts from healthy non-diabetic (Ctr) male Wistar rats were subjected to ischemia and reperfusion (I/R). LV contractility and hemodynamics data were computed digitally whereas cardiac damage following I/R injury was assessed by measuring cardiac enzymes. For ex vivo acute exposure experiments, G6 PAMAM was administered during the first 10 mins of reperfusion in Ctr animals. In chronic in vivo studies, nondiabetic rats (Ctr) received either vehicle or daily i.p. injections of G6 PAMAM (40 mg/kg) for 4 weeks. Diabetic (D) animals received either vehicle or daily i.p. injections of G6 PAMAM (10, 20 or 40 mg/kg) for 4 weeks. The impact of G6 PAMAM on pacing-postconditioning (PPC) was also studied in Ctr and D rats. RESULTS: In ex vivo studies, acute administration of G6 PAMAM to isolated Ctr hearts during reperfusion dose-dependently impaired recovery of cardiac hemodynamics and vascular dynamics parameters following I/R injury. Chronic daily i.p. injections of G6 PAMAM significantly (P<0.01) impaired recovery of cardiac function following I/R injury in nondiabetic animals but this was not generally observed in diabetic animals except for CF which was impaired by about 50%. G6 PAMAM treatment completely blocked the protective effects of PPC in the Ctr animals. CONCLUSION: Acute ex vivo or chronic in vivo treatment with naked G6 PAMAM dendrimer can significantly compromise recovery of non-diabetic hearts from I/R injury and can further negate the beneficial effects of PPC. Our findings are therefore extremely important in the nanotoxicological evaluation of G6 PAMAM dendrimers for potential clinical applications in physiological and pathological settings.

Characterization of a new aerosol antibiotic/adjuvant combination for the treatment of P. aeruginosa lung infections.

The lack of novel classes of antibiotics as well as the constant increase of multidrug resistant bacteria are leaving the clinicians disarmed to treat bacterial infections, especially those caused by Gram-negative pathogens. Among all the investigated solutions, the design of adjuvants able to enhance antibiotics activities appears to be one of the most promising. In this context, a polyamino-isoprenyl derivative has been recently identified to be able to potentiate, at a very low concentration the activity of doxycycline against P. aeruginosa bacterial strains by increasing its intracellular concentration. On the other hand, since aerosol therapy allows a rapid drug administration and targets the respiratory system by avoiding the first pass effect and minimizing undesirable systemic effects, we have developed the first adjuvant/antibiotic combination in an aerosolized form and demonstrated the feasibility of such an approach. Thus, combination aerosol droplets have been demonstrated in sizes suitable for inhalation (3.4 and 4.4 µm mass median aerodynamic diameter and 54 and 60% of the aerodynamic particle size distribution less than 5 µm, as measured for the adjuvant NV716 and doxycycline, respectively and with properties (stoichiometric 1:1 ratio of NV716 salt to drug) that would support further development as an inhaled dosage form. Taken together, our results suggest that these molecules could be successfully delivered at the requested concentration in the lungs and then able to decrease drug consumption as well as increase treatment efficacy.

A dual-functional buformin-mimicking poly(amido amine) for efficient and safe gene delivery.

Biguanides (i.e. metformin, phenformin and buformin) are antidiabetic drugs with potential antitumor effects. Herein, a polycationic polymer, N,N'-bis(cystamine)acrylamide-buformin (CBA-Bu), containing multiple biodegradable disulphide bonds and buformin-mimicking side chains was synthesised. CBA-Bu was equipped with high efficiency and safety profile for gene delivery, meanwhile exhibiting potential antitumor efficacy. As a gene vector, CBA-Bu was able to condense plasmid DNA (pDNA) into nano-sized (<200 nm), positively-charged (>30 mV) uniform polyplexes that were well resistant to heparin and DNase I. Due to the reduction responsiveness of the disulphide bonds, CBA-Bu/pDNA polyplexes could release the loaded pDNA in the presence of dithiothreitol, and induce extremely low cytotoxicity in NIH/3T3 and U87 MG cells. The transfection results showed that CBA-Bu had a cellular uptake efficiency comparable to 25 kDa PEI, while a significantly higher gene expression level. Additionally, CBA-Bu had a lower IC50 value than its non-biguanide counterpart in two cancer cell lines. Furthermore, CBA-Bu could activate AMPK and inhibit mTOR pathways in U87 MG cells, a mechanism involved in the antitumor effect of biguanides. Taken together, CBA-Bu represented an advanced gene vector combining desirable gene delivery capability with potential antitumor activity, which was promising to achieve enhanced therapeutic efficacy in antitumor gene therapy.

A dual-functional implant with an enzyme-responsive effect for bacterial infection therapy and tissue regeneration.

Biomaterial-associated bacterial infection is one of the major causes of implant failure. The treatment of such an implant infection typically requires the elimination of bacteria and acceleration of tissue regeneration around implants simultaneously. To address this issue, an ideal implanted material should have the dual functions of bacterial infection therapy and tissue regeneration at the same time. Herein, an enzyme-responsive nanoplatform was fabricated in order to treat implant-associated bacterial infection and accelerate tissue regeneration in vivo. Firstly, Ag nanoparticles were pre-encapsulated in mesoporous silica nanoparticles (MSNs) by a one-pot method. Then, poly-l-glutamic acid (PG) and polyallylamine hydrochloride (PAH) were assembled by the layer-by-layer (LBL) assembly technique on MSN-Ag to form LBL@MSN-Ag nanoparticles. Furthermore, the LBL@MSN-Ag nanoparticles were deposited on the surface of polydopamine-modified Ti substrates. PG is a homogeneous polyamide composed of an amide linkage, which can be degraded by glutamyl endonuclease secreted by Staphylococcus aureus. Inductively coupled plasma spectroscopy (ICP) results proved that the LBL@MSN-Ag particles show a significant enzyme responsive release of Ag ions. Furthermore, results of antibacterial experiments in vitro showed that the Ti substrates modified with an LBL@MSN-Ag nanocoating presented an excellent antibacterial effect. As for an animal experiment in vivo, in a bacterium infected femur-defect rat model, the modified Ti implants effectively treated bacterial infection. More importantly, the results of micro-CT, haematoxylin-eosin staining and Masson's trichrome staining demonstrated that the modified Ti implants significantly promoted the formation of new bone tissue after implantation for 4 weeks. The present system paves the way for developing the next generation of implants with the functions of treating bacterial infection and promoting tissue regeneration.

Polyamines treatment during pollen germination and pollen tube elongation in tobacco modulate reactive oxygen species and nitric oxide homeostasis.

Several signaling pathways have been shown to be involved in the regulation of pollen germination and pollen tube elongation. Among others, exogenously applied polyamines were found to strongly affect pollen maturation, pollen tube emergence and elongation. In this study, our aim was to investigate the regulatory relation among exogenous polyamines, and endogenous reactive oxygen species and nitric oxide under pollen germination and the apical growth of pollen tube in tobacco plants. We have found that the various polyamines differentially affected the metabolism of nitric oxide and reactive oxygen species during the processes of pollen germination in the grain and the lengthening pollen tube. It is hypothesized that their differential effects might be related to their distinct influence on the endogenous nitric oxide and reactive oxygen species levels.

[Dual antiplatelet therapy for secondary stroke prevention in patients with acute ischemic stroke. CIERTO group recommendation]. / Doble terapia antiagregante en pacientes con accidente cerebrovascular isquémico agudo. Recomendación del grupo CIERTO.

One of the main pillars of acute ischemic stroke management is antiplatelet therapy. Different treatment schemes have been compared, suggesting that the combination of multiple antiplatelet drugs is associated with a reduced risk of stroke recurrence. However, it has also been associated with an increased risk of bleeding complications which, in the long term, surpass the mentioned benefits. However, considering that most stroke recurrences occur i n the short term, a time limited double antiplatelet scheme could result in significant benefits to patients with acute ischemic stroke. On this basis, we conducted a rapid systematic review of the literature in order to evaluate the effects of a short-term double antiplatelet therapy both on stroke recurrence and complications. All trials comparing double versus single antiplatelet therapy in patients with acute ischemic stroke were included. Results showed that double therapy reduces recurrence risk but probably marginally increases major bleeding complications. We suggest double antiplatelet therapy for the initial management of patients with minor (Score NIH < or equal to 3 or transient isquemic attack -TIA) acute ischemic stroke.

El inicio precoz del tratamiento con antiagregantes plaquetarios es considerado el estándar de cuidado para pacientes con accidente cerebrovascular isquémico agudo. Distintos esquemas de antiagregación se han comparado con resultados que sugieren que la combinación de múltiples antiagregantes se asocian a menor riesgo de recurrencia de accidente cerebrovascular (ACV) pero a expensas de un aumento en el riesgo de sangrado, lo que a largo plazo termina opacando dichos beneficos. Sin embargo, considerando que el riesgo de recurrencia de ACV es mayor en el periodo inmediato al evento, la indicación de doble tratamiento antiagregante por tiempos limitados podría asociarse a beneficios relevantes. Con este concepto, se realizó una revisión sistemática rápida con el objetivo de evaluar el efecto del tratamiento con doble antiagregación por un periodo corto intentando maximizar el beneficio y reducir al mínimo el riesgo de sangrado. Se incluyeron todos los estudios primarios identificados en los que se comparó un esquema de doble antiagregación, iniciado en el periodo agudo del evento índice (ACV o accidente isquémico transitorio - AIT), contra un esquema de simple antiagregación. El cuerpo de la evidencia mostró que la intervención (doble antiagregación) reduce el riesgo de recurrencia de ACV y probablemente se asocie a un aumento marginal en el riesgo de sangrado mayor. Sugerimos indicar doble esquema antiplaquetario para el tratamiento inicial de pacientes con ACV isquémico menor (Score NIH < o igual a 3 o AIT).

Doble terapia antiagregante en pacientes con accidente cerebrovascular isquémico agudo: Recomendación del grupo CIERTO / Dual antiplatelet therapy for secondary stroke prevention in patients with acute ischemic stroke. CIERTO group recommendation

El inicio precoz del tratamiento con antiagregantes plaquetarios es considerado el estándar de cuidado para pacientes con accidente cerebrovascular isquémico agudo. Distintos esquemas de antiagregación se han comparado con resultados que sugieren que la combinación de múltiples antiagregantes se asocian a menor riesgo de recurrencia de accidente cerebrovascular (ACV) pero a expensas de un aumento en el riesgo de sangrado, lo que a largo plazo termina opacando dichos beneficos. Sin embargo, considerando que el riesgo de recurrencia de ACV es mayor en el periodo inmediato al evento, la indicación de doble tratamiento antiagregante por tiempos limitados podría asociarse a beneficios relevantes. Con este concepto, se realizó una revisión sistemática rápida con el objetivo de evaluar el efecto del tratamiento con doble antiagregación por un periodo corto intentando maximizar el beneficio y reducir al mínimo el riesgo de sangrado. Se incluyeron todos los estudios primarios identificados en los que se comparó un esquema de doble antiagregación, iniciado en el periodo agudo del evento índice (ACV o accidente isquémico transitorio - AIT), contra un esquema de simple antiagregación. El cuerpo de la evidencia mostró que la intervención (doble antiagregación) reduce el riesgo de recurrencia de ACV y probablemente se asocie a un aumento marginal en el riesgo de sangrado mayor. Sugerimos indicar doble esquema antiplaquetario para el tratamiento inicial de pacientes con ACV isquémico menor (Score NIH < o igual a 3 o AIT).

One of the main pillars of acute ischemic stroke management is antiplatelet therapy. Different treatment schemes have been compared, suggesting that the combination of multiple antiplatelet drugs is associated with a reduced risk of stroke recurrence. However, it has also been associated with an increased risk of bleeding complications which, in the long term, surpass the mentioned benefits. However, considering that most stroke recurrences occur i n the short term, a time limited double antiplatelet scheme could result in significant benefits to patients with acute ischemic stroke. On this basis, we conducted a rapid systematic review of the literature in order to evaluate the effects of a short-term double antiplatelet therapy both on stroke recurrence and complications. All trials comparing double versus single antiplatelet therapy in patients with acute ischemic stroke were included. Results showed that double therapy reduces recurrence risk but probably marginally increases major bleeding complications. We suggest double antiplatelet therapy for the initial management of patients with minor (Score NIH < or equal to 3 or transient isquemic attack -TIA) acute ischemic stroke.

Polyamines in mammalian pathophysiology.

Polyamines (PAs) are essential organic polycations for cell viability along the whole phylogenetic scale. In mammals, they are involved in the most important physiological processes: cell proliferation and viability, nutrition, fertility, as well as nervous and immune systems. Consequently, altered polyamine metabolism is involved in a series of pathologies. Due to their pathophysiological importance, PA metabolism has evolved to be a very robust metabolic module, interconnected with the other essential metabolic modules for gene expression and cell proliferation/differentiation. Two different PA sources exist for animals: PA coming from diet and endogenous synthesis. In the first section of this work, the molecular characteristics of PAs are presented as determinant of their roles in living organisms. In a second section, the metabolic specificities of mammalian PA metabolism are reviewed, as well as some obscure aspects on it. This second section includes information on mammalian cell/tissue-dependent PA-related gene expression and information on crosstalk with the other mammalian metabolic modules. The third section presents a synthesis of the physiological processes described as modulated by PAs in humans and/or experimental animal models, the molecular bases of these regulatory mechanisms known so far, as well as the most important gaps of information, which explain why knowledge around the specific roles of PAs in human physiology is still considered a "mysterious" subject. In spite of its robustness, PA metabolism can be altered under different exogenous and/or endogenous circumstances so leading to the loss of homeostasis and, therefore, to the promotion of a pathology. The available information will be summarized in the fourth section of this review. The different sections of this review also point out the lesser-known aspects of the topic. Finally, future prospects to advance on these still obscure gaps of knowledge on the roles on PAs on human physiopathology are discussed.

Novel Synthetic Polyamines Have Potent Antimalarial Activities in vitro and in vivo by Decreasing Intracellular Spermidine and Spermine Concentrations.

Twenty-two compounds belonging to several classes of polyamine analogs have been examined for their ability to inhibit the growth of the human malaria parasite Plasmodium falciparum in vitro and in vivo. Four lead compounds from the thiourea sub-series and one compound from the urea-based analogs were found to be potent inhibitors of both chloroquine-resistant (Dd2) and chloroquine-sensitive (3D7) strains of Plasmodium with IC50 values ranging from 150 to 460 nM. In addition, the compound RHW, N1,N7-bis (3-(cyclohexylmethylamino) propyl) heptane-1,7-diamine tetrabromide was found to inhibit Dd2 with an IC50 of 200 nM. When RHW was administered to P. yoelii-infected mice at 35 mg/kg for 4 days, it significantly reduced parasitemia. RHW was also assayed in combination with the ornithine decarboxylase inhibitor difluoromethylornithine, and the two drugs were found not to have synergistic antimalarial activity. Furthermore, these inhibitors led to decreased cellular spermidine and spermine levels in P. falciparum, suggesting that they exert their antimalarial activities by inhibition of spermidine synthase.

Therapeutic Potential of Polyamidoamine Dendrimer for Amyloidogenic Transthyretin Amyloidosis.

Amyloidogenic transthyretin (ATTR) amyloidosis is caused by a formation of ATTR amyloid fibrils. Because ATTR misfolding triggers the formation of aggregates and amyloid fibrils, which are considered to deposit on the tissues, novel clinically effective therapeutic strategies targeted to those processes are urgently needed. In this study, to discover a new drug candidate for ATTR amyloidosis therapy, we focused on polyamidoamine dendrimer (dendrimer), a 3D-structural nanomaterial, which has a branched cationic polymer repeating polyamidoamine units. Dendrimer (G2) not only inhibited ATTR V30M amyloid fibril formation, but also reduced already formed ATTR V30M amyloid fibrils by reducing ß-sheet structure of ATTR V30M protein. Moreover, intravenous administration of dendrimer (G2) reduced TTR deposition in human ATTR V30M transgenic rats. These results indicate that dendrimer (G2) may possess both inhibitory and breaking effects on ATTR V30M amyloid, suggesting that dendrimer has the potential as a dual effective agents against TTR amyloidosis.

Polyamidoamine dendrimers-based nanomedicine for combination therapy with siRNA and chemotherapeutics to overcome multidrug resistance.

Multidrug resistance (MDR) significantly decreases the therapeutic efficiency of anti-cancer drugs. Its reversal could serve as a potential method to restore the chemotherapeutic efficiency. Downregulation of MDR-related proteins with a small interfering RNA (siRNA) is a promising way to reverse the MDR effect. Additionally, delivery of small molecule therapeutics simultaneously with siRNA can enhance the efficiency of chemotherapy by dual action in MDR cell lines. Here, we conjugated the dendrimer, generation 4 polyamidoamine (G4 PAMAM), with a polyethylene glycol (PEG)-phospholipid copolymer. The amphiphilic conjugates obtained spontaneously self-assembled into a micellar nano-preparation, which can be co-loaded with siRNA onto PAMAM moieties and sparingly water-soluble chemotherapeutics into the lipid hydrophobic core. This system was co-loaded with doxorubicin (DOX) and therapeutic siRNA (siMDR-1) and tested for cytotoxicity against MDR cancer cells: human ovarian carcinoma (A2780 ADR) and breast cancer (MCF7 ADR). The combination nanopreparation effectively downregulated P-gp in MDR cancer cells and reversed the resistance towards DOX.

Hybrid Alginate@TiO2 Porous Microcapsules as a Reservoir of Animal Cells for Cell Therapy.

The number of patients suffering from diseases linked with hormone deficiency (e.g., type 1 diabetes mellitus) has significantly increased in recent years. As organ transplantation presents its limits, the design of novel robust devices for cell encapsulation is of great interest. The current study reports the design of a novel hybrid alginate microcapsule reinforced by titania via a biocompatible synthesis from an aqueous stable titania precursor (TiBALDH) and a cationic polyamine (PDDAC) under mild conditions. The biocompatibility of this one-pot synthesis was confirmed by evaluation of the cytotoxicity of the precursor, additive, product, and by-product. The morphology, structure, and properties of the obtained hybrid microcapsule were characterized in detail. The microcapsule displayed mesoporous, which was a key parameter to allow the diffusion of nutrients and metabolites and to avoid the entry of immune defenders. The hybrid microcapsule also showed enhanced mechanical stability compared to the pure alginate microcapsule, making it an ideal candidate as a cell reservoir. HepG2 model cells encapsulated in the hybrid microcapsules remained intact for 43 days as highlighted by fluorescent viability probes, their oxygen consumption, and their albumin secretion. The study provides a significant progress in the conception of the robust and biocompatible reservoirs of animal cells for cell therapy.

Development of poly-2-ethyl-2-oxazoline coated gold-core silica shell nanorods for cancer chemo-photothermal therapy.

AIM: Develop a new poly-2-ethyl-2-oxazoline (PEOZ)-based coating for doxorubicin-loaded gold-core mesoporous silica shell (AuMSS) nanorods application in cancer chemo-photothermal therapy. METHODS: PEOZ functionalized AuMSS nanorods were obtained through the chemical grafting on AuMSS of a PEOZ silane derivative. RESULTS: The PEOZ chemical grafting on the surface of AuMSS nanorods allowed the neutralization of nanodevices' surface charge, from -30 to -15 mV, which improved nanoparticles' biocompatibility, namely by decreasing the blood hemolysis to negligible levels. In vitro antitumoral studies revealed that the combined treatment mediated by the PEOZ-coated AuMSS nanorods result in a synergistic effect, allowing the complete eradication of cervical cancer cells. CONCLUSION: The application of the PEOZ coating improves the AuMSS nanorods performance as a multifunctional combinatorial therapy for cervical cancer.

A tumor targeted near-infrared light-controlled nanocomposite to combat with multidrug resistance of cancer.

Stimuli-responsive nanomaterials have emerged as promising drug delivery systems for tumor therapy, as they can specifically respond to tumor-associated stimuli and release the loaded drugs in a controllable manner. However, most currently available stimuli-responsive nanomedicines rely on surrounding extreme stimulus to trigger the activity, which can be inefficient under dynamic and complex living conditions. Herein, we report a near-infrared (NIR) light-responsive nanocomposite, which can generate reactive oxygen species to efficiently trigger the decomposition upon NIR laser irradiation. This nanocomposite is fabricated by conjugating polyamidoamine-pluronic F68 and graphene oxide via diselenide bond, and encapsulating the NIR photosensitizer indocyanine green and chemotherapeutic drug doxorubicin (DOX) as payloads. Under NIR light, the nanocomposite shows lysosomal escape, controlled drug release, and nuclear trafficking of DOX inside multidrug resistant (MDR) MCF-7/ADR cells. Interestingly, this nanocomposite effectively down-regulates ABCB1 gene and P-glycoprotein of MCF-7/ADR cells, exhibiting significant cytotoxicity. In vivo anti-tumor study demonstrates an effective accumulation and superior therapeutic efficacy of this multifunctional nanocomposite in MCF-7/ADR tumors, representing a great potential for clinical treatment of MDR cancer.