State of the Art of Silica Nanoparticles: An Overview on Biodistribution and Preclinical Toxicity Studies.

Over the past few years, nanoparticles have drawn particular attention in designing and developing drug delivery systems due to their distinctive advantages like improved pharmacokinetics, reduced toxicity, and specificity. Along with other successful nanosystems, silica nanoparticles (SNPs) have shown promising effects for therapeutic and diagnostic purposes. These nanoparticles are of great significance owing to their modifiable surface with various ligands, tunable particle size, and large surface area. The rate and extent of degradation and clearance of SNPs depend on factors such as size, shape, porosity, and surface modification, which directly lead to varying toxic mechanisms. Despite SNPs' enormous potential for clinical and pharmaceutical applications, safety concerns have hindered their translation into the clinic. This review discusses the biodistribution, toxicity, and clearance of SNPs and the formulation-related factors that ultimately influence clinical efficacy and safety for treatment. A holistic view of SNP safety will be beneficial for developing an enabling SNP-based drug product.

Budesonide-Loaded Hyaluronic Acid Nanoparticles for Targeted Delivery to the Inflamed Intestinal Mucosa in a Rodent Model of Colitis.

The aim of the present study was to investigate the therapeutic potential of budesonide- (BDS-) loaded hyaluronic acid nanoparticles (HANPs) for treatment of inflammatory bowel disease (IBD) using an acute model of colitis in rats. The therapeutic efficacy of BDS-loaded HANPs in comparison with an aqueous suspension of the drug with the same dose (30 µg/kg) was investigated 48 h following induction of colitis by intrarectal administration of acetic acid 4% in rats. Microscopic and histopathologic examinations were conducted in inflamed colonic tissue. Tissue concentration of tumor necrosis factor (TNF)-α was assessed by ELISA assay kit, while the activity of myeloperoxidase (MPO) was measured spectrophotometrically. Results from in vivo evaluations demonstrated that administrations of BDS-HANPs ameliorated the general endoscopic appearance, quite close to the healthy animals with no signs of inflammation and reduced the cellular infiltration, as well as the TNF-α level, and the MPO activity. It was found that delivery by BDS-loaded HANPSs alleviated the induced colitis significantly better than the same dose of the free drug. These data further suggest the potential of HANPs as a targeted drug delivery system to the inflamed colon mucosa.

Protective effects of atorvastatin and rosuvastatin on 3,4-methylenedioxymethamphetamine (MDMA)-induced spatial learning and memory impairment.

3,4-Methylenedioxymethamphetamine (MDMA) or "Ecstasy", which has been used for recreational purposes, is shown to impair memory and brain functions. Statins, beyond their efficient cholesterol-lowering impact through inhibition of HMG-COA reductase enzyme, possess multiple actions referred to as pleiotropic effects. In this regard, we aimed to investigate the neuroprotective effects of atorvastatin and rosuvastatin on MDMA-induced neurotoxicity. Adult male Wistar rats received atorvastatin (5, 10, and 20 mg/kg; orally) and rosuvastatin (5, 10, 20 mg/kg; orally) for 21 consecutive days. Then, spatial memory and learning were evaluated by Morris water maze (MWM) test. Rats were intraperitoneally injected with MDMA (2.5, 5, and 10 mg/kg) 30 min before the first training session in 4 training days of MWM task. Afterward, rats were euthanized and their hippocampuses were dissected to evaluate reactive oxygen species (ROS) production, lipid peroxidation (LPO), and caspase-3 and -9 activities. Our findings showed that MDMA (5 and 10 mg/kg) significantly impaired spatial memory functions and dramatically increased ROS production, LPO, and caspase-3 and -9 activities compared to control. Also, atorvastatin (5, 10, and 20 mg/kg) and rosuvastatin (20 mg/kg) significantly improved memory performances and inhibited the elevation of ROS, LPO, and caspase-3 and -9 activities induced by MDMA. In conclusion, the results indicated that MDMA-induced cognitive impairment is followed by oxidative stress and activation of apoptotic pathways in the hippocampus. However, atorvastatin and rosuvastatin suppressed these deleterious consequences of MDMA and revealed protective effects against activation of pathways leading to cell damage.

Involvement of nitrergic system in anticonvulsant effect of zolpidem in lithium-pilocarpine induced status epilepticus: Evaluation of iNOS and COX-2 genes expression.

This study aims to investigate the role of zolpidem in lithium-pilocarpine induced status epilepticus (SE) and probable mechanisms involved in seizure threshold alteration. In the present study, lithium chloride (127mg/kg) was administered 20h prior to pilocarpine (60mg/kg) to induce SE in adult male Wistar rats. Different doses of zolpidem (0.1, 1, 2, 5, 10mg/kg) were injected 30min before pilocarpine administration. Furthermore, to find out whether nitric oxide (NO) plays a role in the observed effect, L-arginine and L-NAME were injected 15min before zolpidem. Afterward, we identified the particular NO isoform mediating the effect of zolpidem by injecting aminoguanidine (AG) and 7-Nitroindazole (7-NI) 15min prior to zolpidem. Moreover, in both 6 and 24h after pilocarpine injection, experimental groups underwent hippocampectomy to evaluate cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) genes expression by quantitative reverse transcription-PCR (qRT-PCR). Pre-treatment with zolpidem significantly prevented the onset of SE in a dose-dependent manner. AG and L-NAME significantly potentiated the anticonvulsant effect of zolpidem while L-arginine inverted this effect. Our qRT-PCR exerted that there was a continuous elevation of iNOS and COX-2 genes expression over 6 and 24h after pilocarpine administration in SE and L-arginine+Zolpidem groups while in AG/L-NAME+Zolpidem and zolpidem groups this upregulation was prevented. Our study indicates that zolpidem prevents the onset of SE through inhibition of iNOS/COX-2 genes upregulation following lithium-pilocarpine administration. Consistent with our results, we suggest that iNOS activation could be probably upstream of COX-2 gene expression.

Does Evolocumab, as a PCSK9 Inhibitor, Ameliorate the Lipid Profile in Familial Hypercholesterolemia Patients? A Meta-Analysis of Randomized Controlled Trials.

Proprotein convertase subtilisin-kexin type 9 (PCSK9) is a member of regulatory serine proteases which is mostly expressed in liver. In the physiological condition, LDL-C binds to LDL receptors (LDLRs) and via endocytosis, LDLRs are degraded. PCSK9 binds to the epidermal growth factor-like repeat A (EGFA) domain of extracellular LDLRs, and then physiological recycling of LDLRs from surface of liver is cancelled, resulting in elevation of circulating LDL-C in plasma. To evaluate whether evolucomab, as PCSK9 inhibitor monoclonal antibody, ameliorates lipid profile in familial hypercholesterolemia (FH) patients, this meta-analysis has been conducted. PubMed, Web of Science (ISI) and Scopus databases were searched for studies which had investigated the efficacy of evolucomab. Types of outcome investigated were percentage changes from baseline of the lipid profile. Our meta-analysis shows that evolucomab at the dosage of 420 mg monthly could decrease LDL-C  by 54.71%, TC by 35.08%, VLDL-C by 28.37 %, ratio of TC to HDL-C by 39.14 %, triglycerides by 12.11 %, and increased HDL-C by 6.06% from baseline compared to placebo at the end of study in FH patients. Our findings indicate that evolocumab could be a hopeful agent for challenging patients, such as statin intolerance or patients who fail to attain the target goal of LDL-C despite consumption of maximum doses of statins. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Anticonvulsive Effects of Licofelone on Status Epilepticus Induced by Lithium-pilocarpine in Wistar Rats: a Role for Inducible Nitric Oxide Synthase.

BACKGROUND AND PURPOSE: Status epilepticus (SE) is a neurological disorder with high prevalence and mortality rates, requiring immediate intervention. Licofelone is a cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) inhibitor, which its effectiveness to treat osteoarthritis has been approved. Increasing evidence suggests an involvement of COX and LOX enzymes in epileptic disorders. Thus, in the present study we investigate possible effects of licofelone on prevention and termination of SE. We also evaluated whether the nitrergic system could participate in this effect of licofelone. METHODS: We have utilized lithium-pilocarpine model of SE in adult Wistar rats to assess the potential effect of licofelone on seizure susceptibility. Licofelone was administered 1 h before pilocarpine. To evaluate probable role of nitric oxide (NO) system, L-arginine (60 mg/kg, i.p.), as a NO precursor; L-NAME (15 mg/kg, i.p.), as a non-selective nitric oxide synthase (NOS) inhibitor; aminoguanidine (100 mg/kg, i.p.), as an inducible NOS (iNOS) inhibitor and 7-nitroindazole (60 mg/kg, i.p.), as a neuronal NOS inhibitor were injected 15 min before licofelone. Also, licofelone and diazepam 10 mg/kg were administered 30 minutes after onset of SE. RESULTS: Pre-treatment with licofelone at the dosage of 10 mg/kg, significantly prevented the onset of SE in all subjects (p < 0.001). L-arginine significantly inverted this anticonvulsant effect (p < 0.05). However, L-NAME and aminoguanidine, potentiated the anticonvulsant effect of licofelone (p < 0.05, p < 0.01). Licofelone could not terminate seizures after onset which was terminated by diazepam. CONCLUSIONS: Our findings showed that anticonvulsive effects of licofelone on SE could be mediated by iNOS. Also, we suggest that COX/5-LOX activation is possibly required in the initial stage of onset but SE recruits extra excitatory pathways with prolongation.