Reduction of class I histone deacetylases ameliorates ER-mitochondria cross-talk in Alzheimer's disease.

Several molecular mechanisms have been described in Alzheimer's disease (AD), including repressed gene transcription and mitochondrial and endoplasmic reticulum (ER) dysfunction. In this study, we evaluate the potential efficacy of transcriptional modifications exerted by inhibition or knockdown of class I histone deacetylases (HDACs) in ameliorating ER-mitochondria cross-talk in AD models. Data show increased HDAC3 protein levels and decreased acetyl-H3 in AD human cortex, and increased HDAC2-3 in MCI peripheral human cells, HT22 mouse hippocampal cells exposed to Aß1-42 oligomers (AßO) and APP/PS1 mouse hippocampus. Tacedinaline (Tac, a selective class I HDAC inhibitor) counteracted the increase in ER-Ca2+ retention and mitochondrial Ca2+ accumulation, mitochondrial depolarization and impaired ER-mitochondria cross-talk, as observed in 3xTg-AD mouse hippocampal neurons and AßO-exposed HT22 cells. We further demonstrated diminished mRNA levels of proteins involved in mitochondrial-associated ER membranes (MAM) in cells exposed to AßO upon Tac treatment, along with reduction in ER-mitochondria contacts (MERCS) length. HDAC2 silencing reduced ER-mitochondria Ca2+ transfer and mitochondrial Ca2+ retention, while knockdown of HDAC3 decreased ER-Ca2+ accumulation in AßO-treated cells. APP/PS1 mice treated with Tac (30 mg/kg/day) also showed regulation of mRNA levels of MAM-related proteins, and reduced Aß levels. These data demonstrate that Tac normalizes Ca2+ signaling between mitochondria and ER, involving the tethering between the two organelles in AD hippocampal neural cells. Tac-mediated AD amelioration occurs through the regulation of protein expression at MAM, as observed in AD cells and animal models. Data support transcriptional regulation of ER-mitochondria communication as a promising target for innovative therapeutics in AD.

Dermatopharmacokinetic and pharmacodynamic evaluation of a novel nanostructured formulation containing capsaicinoids for treating neuropathic pain.

The in vivo skin penetration by dermal microdialysis and the pharmacological efficacy of a chitosan hydrogel containing capsaicinoids-loaded nanocapsules (CHNCCaps) was evaluated in this study. Such gel has previously been proven to control capsaicinoids release and decrease the drugs side effects in humans. The nanocapsules containing capsaicinoids had an average size around 150 nm, with a low polydispersity index, positive zeta potential, and high encapsulation efficiency of the drugs. The CHNCCaps showed intact nanocapsules, a slightly acid pH value, and a pseudoplastic behavior suitable for topical application. Microdialysis experiments showed a 1.6-fold increase in the concentration of capsaicinoids in the dermis (after 12 h of its application) when CHNCCaps was administered compared to a chitosan hydrogel containing capsaicinoids in hydroethanolic solution (CHETCaps) and the commercial cream. The CHNCCaps showed antiallodynic and antihyperalgesic effects from 6 h to 96 h after treatment initiation, whereas CHETCaps and the commercial cream showed antiallodynic and antihyperalgesic effects only at 48 h and 96 h after treatment initiation, respectively. CHNCCaps and the commercial cream maintained antihyperalgesic activity for 6 days after treatment interruption. For mechanical allodynia, the antinociceptive effect was maintained for 48 h after treatment interruption only with CHNCCaps. In conclusion, CHNCCaps is a promising formulation for treating peripheral neuropathic pain.

Lipid-core nanocapsules containing simvastatin improve the cognitive impairment induced by obesity and hypercholesterolemia in adult rats.

The development of cognitive impairment may be related to high levels of plasma cholesterol and obesity. Simvastatin (SV) and lovastatin (LV) are drugs that can potentially be used for the treatment of cognitive deficit. This study aimed to develop and characterize lipid-core nanocapsules (LNC) containing SV (SV-LNC) or LV (LV-LNC), evaluating the effects of SV-LNC in an animal model of cognitive deficit. The formulations SV-LNC and LV-LNC presented a particle average size around 200 nm, a low-polydispersity index, and negative zeta potential. Analysis of differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy showed that there is no reaction among LNC components: LV was crystallized in the suspensions, and SV was molecularly dispersed. The encapsulation efficiency of the SV was high (98.9 ± 1.4%), while that of the LV was low (21.5 ± 1.5%).Based on these results, SV-LNC was used in the preclinical studies. Animals fed with a hyperlipidic diet (HD) developed obesity, hypercholesterolemia, and cognitive impairment, which was corroborated by the brain lesions indicated by histological analysis of some of the animals that received the high-fat diet. We observed that free simvastatin (CS3) was able to reduce the enzymatic activity of pyruvate kinase, an important enzyme for brain energy homeostasis, without affecting the memory of the animals that received a standard diet. However, it failed to improve the cognitive damage caused by a diet high in cholesterol and saturated fats. On the other hand, when simvastatin is "camouflaged" in the lipid-core nanocapsules (HNS3), this cognitive impairment improves. Thus, SV-LNC is a promising alternative therapy for the treatment of cognitive impairment.

Glioblastoma chemotherapeutic agents used in the clinical setting and in clinical trials: Nanomedicine approaches to improve their efficacy.

Even though substantial advances in understanding glioma pathogenesis have prompted a more rational design of potential therapeutic strategies, glioblastoma multiforme remains an incurable disease with the lowest median overall survival among all malignant brain tumours. Therefore, there is a dire need to find novel drug delivery strategies to improve the current dismal survival outcomes. In this context, nanomedicine offers an appealing alternative as it shows potential to improve brain drug delivery. Accordingly, we here review nanomedicine-based drug delivery strategies tested in orthotopic animal models of glioblastoma intended to improve the efficacy of the drug candidates that are currently used in the clinical setting or that have entered clinical trials for the treatment of glioblastoma multiforme. We also outline the future perspectives of nanotechnology to provide emerging glioblastoma treatment with broad translational clinical potential based on the nanocarriers that have already entered the clinical trials stage for the treatment of malignant glioma.

Lipid-core nanocapsules are an alternative to the pulmonary delivery and to increase the stability of statins.

Aims: Lipid-core nanocapsules (LNCs) loaded with simvastatin (SV, SV-LNC) or lovastatin (LV, LV-LNC) were formulated for pulmonary administration. Methods: The LNC suspensions were characterized physicochemically, their stability was evaluated, and drug delivery by the pulmonary route was tested in vitro. Results: The loaded LNCs had a particle size close to 200 nm, a low polydispersity index, and a zeta potential around -20 mV. The encapsulation efficiency was high for SV (99.21 ± 0.7%) but low for LV (20.34 ± 1.2%). SV release from nanocapsules was slower than it was from SV in solution, with a monoexponential release profile, and the drug emitted and aerosol output rate was higher for SV-LNCs (1.58 µg/s) than for SV in suspension (0.54 µg/s). Conclusions: SV-LNCs had a median aerodynamic diameter of 3.51 µm and a highly respirable fraction (61.9%), indicating that nanoparticles are a suitable system for efficient delivery of simvastatin to the lung.

Rapid and sensitive LC-MS/MS method for simultaneous quantification of capsaicin and dihydrocapsaicin in microdialysis samples following dermal application.

A bioanalytical LC-MS/MS method was developed and validated for the simultaneous quantification of capsaicin (CAPS) and dihydrocapsaicin (D-CAPS) in dermal microdialysis samples from rats. Capsaicinoids were separated by using a C18 column, with a mobile phase of water and acetonitrile, both with 0.1% of formic acid, eluted as a gradient. Compounds were detected by using an electrospray ionization source operating in the positive mode (ESI+) to monitor the m/z transitions of 306.1 > 137.0 for CAPS and 308.1 > 137.0 for D-CAPS. The method showed linearity in the concentration range of 0.5-100 ng/ml for CAPS and 0.25-100 ng/ml for D-CAPS, with coefficients of determination of ≥ 0.99. The inter- and intra-day precision, accuracy, and compound stability in different conditions were in accordance with the limits established by the US Food and Drug Administration guidelines. The recovery of the drugs by microdialysis were dependent on the flow rate, but independent of drug concentration. For CAPS, calibration of the in vitro microdialysis probes by dialysis and retrodialysis resulted in statistically similar drug recovery of 68.5% ± 5.9% and 77.8% ± 6.6%, respectively, at a flow rate of 0.5 µl/min. For D-CAPS, the recovery by dialysis was lower than by retrodialysis, at 51.4% ± 6.6% and 92.6% ± 2.4%, respectively. This difference was attributed to the binding of D-CAPS to the plastic tubing, which was experimentally evaluated and mathematically modeled. In vivo recoveries were 75.7% ± 6.3% for CAPS and 81.9% ± 1.5% for D-CAPS at the same flow rate. The analytical method showed high specificity, accuracy, and sensitivity, and suitability for dermatopharmacokinetic studies. These results will allow the determination of the actual free concentration of these drugs in dermatopharmacokinetic experiments, as shown in a pilot experiment with a commercial cream containing capsaicinoids.

Chitosan hydrogels containing nanoencapsulated phenytoin for cutaneous use: Skin permeation/penetration and efficacy in wound healing.

Although phenytoin is an antiepileptic drug used in the oral treatment of epilepsy, its off-label use as a cutaneous healing agent has been studied in recent years due to the frequent reports of gingival hyperplasia after oral administration. However, the cutaneous topical application of phenytoin should prevent percutaneous skin permeation. Therefore, the aim of this study was to evaluate the in vitro skin permeation/retention and in vivo effects of nanocapsules and nanoemulsions loaded with phenytoin and formulated as chitosan hydrogels on the healing process of cutaneous wounds in rats. The hydrogels had adequate pH values (4.9-5.6) for skin application, drug content of 0.025% (w/w), and non-Newtonian pseudoplastic rheological behaviour. Hydrogels containing nanocapsules and nanoemulsions enabled improved controlled release of phenytoin and adhesion to skin, compared with hydrogels containing non-encapsulated phenytoin. In vitro skin permeation studies showed that phenytoin permeation to the receptor compartment, and consequently the risk of systemic absorption, may be reduced by nanoencapsulation without any change in the in vivo performance of phenytoin in the wound healing process in rats.

Natural lipid nanoparticles containing nimesulide: synthesis, characterization and in vivo antiedematogenic and antinociceptive activities.

Lipid nanoparticles are drug delivery systems able to increase bioavailability of poorly soluble drugs. They can be prepared with different lipid materials, especially natural lipids. Shea butter is a natural lipid obtained from the Butyrospermum parkii seed and rich in oleic and stearic acids. Nimesulide is a COX 2 selective anti-inflammatory that is poorly soluble in water. The purpose of this study was to develop and characterize shea butter lipid nanoparticles using a new technique and evaluate the in vivo activity of these nanoparticles. Lipid nanoparticles were prepared by melting shea butter and mixing with an aqueous phase using a high shear mixer. The nanoparticles presented pH of 6.9 +/- 0.1, mean particle size of 90 nm and a narrow polydispersity (0.21). Zeta potential was around -20 mV and the encapsulation efficiency was 97.5%. Drug release was evaluated using dialysis bags and presented monoexponential profile with t50% of 4.80 h (free drug t50% was only 2.86 h). Antinociceptive activity was performed by the acetic acid model. Both nimesulide and nimesulide-loaded nanoparticles presented significant activity compared to the control. The in vivo anti-inflammatory activity was evaluated by paw edema and was statistically different for the nanoparticles containing nimesulide compared to free nimesulide, blank nanoparticles and saline. In conclusion, the use of shea butter as encapsulating lipid was very successful and allowed nanoparticles to be prepared with a very simple technique. The nanoparticles presented significant pharmacological effects that were not seen for free drug administration.