Parkinson’s disease (PD) is a neurodegenerative disorder associated primarily with loss of dopamine (DA) neurons in the nigrostriatal system. With the aim of increasing the bioavailability of
l
-dopa ...(LD) after oral administration and of overcoming the pro-oxidant effect associated with LD therapy, we designed a peptidomimetic LD prodrug (
1
) able to release the active agent by enzyme catalyzed hydrolysis. The physicochemical properties, as well as the chemical and enzymatic stabilities of the new compound, were evaluated in order to check both its stability in aqueous medium and its sensitivity towards enzymatic cleavage, providing the parent LD drug, in rat and human plasma. The radical scavenging activities of prodrug
1
was tested by using both the DPPH–HPLC and the DMSO competition methods. The results indicate that the replacement of cysteine GSH portion by methionine confers resistance to oxidative degradation in gastric fluid. Prodrug
1
demonstrated to induce sustained delivery of DA in rat striatal tissue with respect to equimolar LD dosages. These results are of significance for prospective therapeutic application of prodrug
1
in pathological events associated with free radical damage and decreasing DA concentration in the brain.
Current evidences support the hypothesis that non‐steroidal anti‐inflammatory drugs (NSAIDs) and antioxidant therapy might protect against the development of Alzheimer's disease (AD). In the present ...work, our attention was focused on ibuprofen (IBU) used in clinical trails to prevent Alzheimer's disease, and (R)‐α‐lipoic acid (LA) considered as a potential neuroprotective agent in AD therapy. In particular, we investigated a series of lipophilic molecular combinations obtained by joining (R)‐α‐lipoic acid and ibuprofen via an amide bond. These new entities might allow targeted delivery of the parent drugs to neurons, where cellular oxidative stress and inflammation seem related to Alzheimer's disease. Our study included the synthesis of conjugates 1–3 and the evaluation of their physicochemical and in‐vitro antioxidant properties. The new compounds are extremely stable in aqueous buffer solutions (pH = 1.3 and 7.4), and in rat and human plasma they showed a slow bioconversion to ibuprofen and (R)‐α‐lipoic acid. Codrugs 1–3 displayed in vitro free radical scavenging activity and were hydrolyzed more rapidly in brain tissue than in rat serum indicating that these new entities might allow targeted delivery of the parent drugs to neurons. The immunohistochemical analysis of Aβ (1‐40) protein showed that Aβ‐injected cerebral cortices treated with ibuprofen or compound 1 showed few plaques within capillary vessels and, in particular, Aβ (1‐40) protein was less expressed in codrug‐1‐treated than in ibuprofen‐treated cerebral cortex.
A series of multifunctional codrugs (1−4), obtained by joining L-Dopa (LD) and dopamine (DA) with (R)-α-lipoic acid (LA), was synthesized and evaluated as potential codrugs with antioxidant and ...iron-chelating properties. These multifunctional molecules were synthesized to overcome the pro-oxidant effect associated with LD therapy. The physicochemical properties, together with the chemical and enzymatic stabilities of synthesized compounds, were evaluated in order to determine both their stability in aqueous medium and their sensitivity in undergoing enzymatic cleavage by rat and human plasma to regenerate the original drugs. The new compounds were tested for their radical scavenging activities, using a test involving the Fe (II)−H2O2-induced degradation of deoxyribose, and to evaluate peripheral markers of oxidative stress such as plasmatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the plasma. Furthermore, we showed the central effects of compounds 1 and 2 on spontaneous locomotor activity of rats in comparison with LD-treated animals. From the results obtained, compounds 1−4 appeared stable at a pH of 1.3 and in 7.4 buffered solution; in 80% human plasma they were turned into DA and LD. Codrugs 1−4 possess good lipophilicity (log P > 2 for all tested compounds). Compounds 1 and 2 seem to protect partially against the oxidative stress deriving from auto-oxidation and MAO-mediated metabolism of DA. This evidence, together with the “in vivo” dopaminergic activity and a sustained release of the parent drug in human plasma, allowed us to point out the potential advantages of using 1 and 2 rather than LD in treating pathologies such as Parkinson's disease, characterized by an evident decrease of DA concentration in the brain.
The purpose of this study was to prepare and characterize nanocarrier systems, which allow the application of pDNA vaccines and adjuvants to mucosal vaccination. Chitosan from a vegetal source ...(Agaricus bisporus) and of GMP quality was used to synthesize the derivative 6-O-carboxymethyl-N,N,N-trimethylchitosan (CM-TMC). Toll-like receptor-2 (TLR-2) agonist, Pam3Cys, was synthesized and coupled to CM-TMC through a polyethylene glycol (PEG) spacer. Successively, Pam3Cys decorated nanocarriers were prepared by complexation with plasmid DNA (pDNA) expressing green fluorescence protein (GFP), and characterized with respect to their physicochemical properties and protection of the included plasmid against DNase I enzymatic degradation. In vitro studies using phorbol 12-myristyl 13-acetate (PMA) stimulated macrophage-like THP-1 (mTHP-1) cells were focused on cytotoxicity of both polymers and particles, and their potential to stimulate IL-8 release via the TLR-2 pathway. Our results showed that the TLR-2 functionalized pDNA nanocarriers have the ability to complex and to protect pDNA against enzymatic degradation. pDNA nanocarriers were of around 400 nm in size, and displayed a positive zeta potential of 27.9 ± 1.6 mV. Chitosan, CM-TMC, and Pam3Cys-functionalized CM-TMC polymers displayed cytotoxicity on mTHP1 cells in a concentration-dependent manner, which decreased by 50-fold on complexation with pDNA. In addition, decorated pDNA nanocarriers induced IL-8 secretion by mTHP-1 macrophages, which was increased by 10-fold as compared to nondecorated carriers.
Summary
The viscoelastic properties of mono‐microbial biofilms produced by ocular and reference staphylococcal strains were investigated. The microorganisms were characterized for their haemolytic ...activity and agr typing and the biofilms, grown on stainless steel surface under static conditions, were analysed by Confocal Laser Scanning Microscopy. Static and dynamic rheometric tests were carried out to determine the steady‐flow viscosity and the elastic and viscous moduli. The analysed biofilms showed the typical time‐dependent behaviour of viscoelastic materials with considerable elasticity and mechanical stability except for Staphylococcus aureus ATCC 29213 biofilm which showed a very fragile structure. In particular, S. aureus 6ME biofilm was more compact than other staphylococcal biofilms studied with a yield stress ranging between 2 and 3 Pa. The data obtained in this work could represent a starting point for developing new therapeutic strategies against biofilm‐associated infections, such as improving the drug effect by associating an antimicrobial agent with a biofilm viscoelasticity modifier.
The maleic and fumaric diamides preparation of (O,O-diacetyl)-L-Dopa-methylester (+)-4, (+)-5 are reported; they were synthesized in order to attenuate marked fluctuations of L-DOPA (LD) plasma ...levels and to overcome the problem of low bioavailability of LD. The new compounds were characterized evaluating solubility, chemical stability, apparent partition coefficient (log P) and comparing neostriatum dopamine (DA) levels in freely moving rats after i.p. administration of prodrugs (+)-4, (+)-5 with prodrugs in liposomal formulations (+)-4 Lip, (+)-5 Lip. All the new compounds showed chemical stability in aqueous buffer solutions (pH 1.3 and 7.4). A relatively slow release of LD in human plasma was observed. Among the studied products, prodrug was able to induce sustained delivery of DA in rat striatal dialysate with respect to equimolar i.p admistration of LD. Furthermore, neostriatum DA concentration after administration of the synthesized prodrugs vs. prodrugs in liposomal formulations was compared (+)-4 Lip, (+)-5 Lip). The results suggest that cis dimeric prodrug (+)-4 and (+)-4 Lip can improve the release of DA in rat brain and demonstrate the potential of these formulations for controlled delivery of antiparkinson agents.
This paper reports the synthesis and preliminary evaluation of new L‐dopa (LD) conjugates (1 and 2) obtained by joining LD with two different natural antioxidants, caffeic acid and carnosine, ...respectively. The antioxidant efficacy of compounds 1 and 2 was assessed by evaluating plasmatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the rat. Rat striatal concentration of LD and dopamine (DA), and central nervous effects were evaluated after oral administration of the codrugs 1 and 2. The results suggest that, though our codrugs are devoid of significant antioxidant activity, they are able to induce sustained delivery of DA in rat striatum and can improve LD and DA release in the brain.
Extracellular DNA (eDNA) is an important component of the extracellular polymeric substance matrix and is important in the establishment and persistence of Staphylococcus aureusUAMS-1 biofilms. The ...aim of the study was to determine the temporal expression of genes involved in early biofilm formation and eDNA production. We used qPCR to investigate expression of agrB, which is associated with secreted virulence factors and biofilm dispersal, cidA, which is associated with biofilm adherence and genomic DNA release, and alsS, which is associated with cell lysis, eDNA release and acid tolerance. The contribution of eDNA to the stability of the biofilm matrix was assessed by digesting with DNase I (Pulmozyme) and quantifying structure by confocal microscopy and comstat image analysis. AgrB expression initially increased at 24 h but then dramatically decreased at 72 h in an inverse relationship to biomass, supporting its role in regulating biofilm dispersal. cidA and alsS expression steadily increased over 72 h, suggesting that eDNA was an important component of early biofilm development. DNase I had no effect on biomass, but did cause the biofilms to become more heterogeneous. Carbohydrates in the matrix appeared to play an important role in structural stability.
•Neurotrophins are currently investigated as risk factors and therapeutic marked for psychiatric disorders.•Vagus Nerve Stimulation (VNS) up-regulates neurotrophins in brain and activates plasticity ...and neurogenesis.•From daVagus nerve and NGF/BDNF are part of an integrated body system, which works to alert, cope and protect.•VNS-induced NGF and BDNF changes might help to develop personalized therapies for psychiatric patients patients.
Since 2004, vagus nerve stimulation (VNS) has been used in treatment-resistant or treatment-intolerant depressive episodes. Today, VNS is suggested as possible therapy for a larger spectrum of psychiatric disorders, including schizophrenia, obsessive compulsive disorders, and panic disorders. Despite a large body of literature supports the application of VNS in patients’ treatment, the exact mechanism of action of VNS remains not fully understood. In the present study, the major knowledges on the brain areas and neuronal pathways regulating neuroimmune and autonomic response subserving VNS effects are reviewed. Furthermore, the involvement of the neurotrophins (NTs) Nerve Growth Factor (NGF) and Brain Derived Neurotrophic Factor (BDNF) in vagus nerve (VN) physiology and stimulation is revised. The data on brain NGF/BDNF synthesis and in turn on the activity-dependent plasticity, connectivity rearrangement and neurogenesis, are presented and discussed as potential biomarkers for optimizing stimulatory parameters for VNS. A vagus nerve-neurotrophin interaction model in the brain is finally proposed as a working hypothesis for future studies addressed to understand pathophysiology of psychiatric disturbance.
Nerve Growth Factor in Alcohol Use Disorders Ceci, Flavio Maria; Ferraguti, Giampiero; Petrella, Carla ...
Current neuropharmacology,
01/2021, Letnik:
19, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The nerve growth factor (NGF) belongs to the family of neurotrophic factors. Initially discovered as a signaling molecule involved in the survival, protection, differentiation, and proliferation of ...sympathetic and peripheral sensory neurons, it also participates in the regulation of the immune system and endocrine system. NGF biological activity is due to the binding of two classes of receptors: the tropomyosin-related kinase A (TrkA) and the low-affinity NGF pan-neurotrophin receptor p75. Alcohol Use Disorders (AUD) are one of the most frequent mental disorders in developed countries, characterized by heavy drinking, despite the negative effects of alcohol on brain development and cognitive functions that cause individual’s work, medical, legal, educational, and social life problems. In addition, alcohol consumption during pregnancy disrupts the development of the fetal brain causing a wide range of neurobehavioral outcomes collectively known as fetal alcohol spectrum disorders (FASD). The rationale of this review is to describe crucial findings on the role of NGF in humans and animals, when exposed to prenatal, chronic alcohol consumption, and on binge drinking.
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