Silica Release from Silane Cross-Linked Gelatin Based Hybrid Scaffold Affects Cell Proliferation.

Earlier, we had reported the synthesis and characterization of star-shaped poly(d,l-lactide)-b-gelatin (ss-pLG) to improve cell adhesion and proliferation, but the stability of ss-pLG scaffolds remained a persistent issue. Here we show an increase in the stability of ss-pLG using 3-glycidoxypropyl trimethoxysilane (GPTMS) as a covalent cross-linker (h-ss-pLG). The rate of cell proliferation within Hep-G2 cultured h-ss-pLG scaffolds increased until the third day, and afterward it drastically declined. Further, we identified the release of inorganic silica from GPTMS cross-linked h-ss-pLG, which may be associated with the decrease in the rate of HepG2 cell proliferation. However, the cross-linking did not affect red blood cells (RBCs) and they were completely hemocompatible. In addition, our in vivo experiments in female rats showed that the hybrid h-ss-pLG scaffolds were not degraded completely after 4 weeks, as they were covalently cross-linked with silane. These results suggest the significance of the cross-linker selection, which is one of the other key factors, and needs to be considered while designing scaffolds.

Development of pyrazole and spiropyrazoline analogs as multifunctional agents for treatment of Alzheimer's disease.

Cholinergic hypothesis of Alzheimer's disease has been advocated as an essential tool in the last couple of decades for the drug development. Here in, we report de novo fragment growing strategy for the design of novel 3,5-diarylpyrazoles and hit optimization of spiropyrazoline derivatives as acetyl cholinesterase inhibitors. Both type of scaffolds numbering forty compounds were synthesized and evaluated for their potencies against AChE, BuChE and PAMPA. Introduction of lipophilic cyclohexane ring in 3,5-diarylpyrazole analogs led to spiropyrazoline derivatives, which facilitated and improved the potencies. Compound 44 (AChE = 1.937 ±â€¯0.066 µM; BuChE = 1.166 ±â€¯0.088 µM; hAChE = 1.758 ±â€¯0.095 µM; Pe = 9.491 ±â€¯0.34 × 10-6 cm s1) showed positive results, which on further optimization led to the development of compound 67 (AChE = 0.464 ±â€¯0.166 µM; BuChE = 0.754 ±â€¯0.121 µM; hAChE = 0.472 ±â€¯0.042 µM; Pe = 13.92 ±â€¯0.022 × 10-6 cm s1). Compounds 44 and 67 produced significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE. They were found to be safer to MC65 cells and decreased metal induced Aß1-42 aggregation. Further, in-vivo behavioral studies, on scopolamine induced amnesia model, the compounds resulted in better percentage spontaneous alternation scores and were safe, had no influence on locomotion in tested animal groups at dose of 3 mg/kg. Early pharmacokinetic assessment of optimized hit molecules was supportive for further drug development.

Neuroprotective effect of chlorogenic acid in global cerebral ischemia-reperfusion rat model.

The ischemic cascade is initiated in the hypoperfused region of the brain that leads to neuronal cell death. Identification of multi-target inhibitor against prominent molecular mediators of ischemic cascade might be a suitable strategy to combat cerebral ischemic stroke. The present study is designed to evaluate the neuroprotective efficacy of chlorogenic acid (CGA) in the global cerebral ischemic rat model. The effective dose of CGA was evaluated on the basis of reduction in cerebral infarction area percentage, Evans blue extravasation, and restoration of brain water content. The expression of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and caspase-3 was evaluated by immunohistochemistry and morphological and cellular alterations in the cortex were observed by brain histology. The level of glutamate, calcium, and nitrate in different regions of the brain, as well as cerebrospinal fluid (CSF), was evaluated. The level of calcium and nitrate was compared with ifenprodil-an antagonist of N-methyl-D-aspartate receptor (NMDAR) and 7-nitroindazole-an inhibitor of neuronal nitric oxide synthase (nNOS) respectively. Further, molecular docking was performed to compare the inhibition potential of CGA against NMDAR and nNOS with their inhibitors. Dose optimization results revealed that intranasal administration of CGA (10 mg/kg b.w.) significantly reduced the cerebral infarction area, Evans blue extravasation and restored the brain water content compared with ischemia group. It also significantly reduced the calcium, nitrate, and glutamate levels compared with ischemia group in the cortex, hippocampus cerebellum, and CSF. Immunohistochemical analysis revealed that CGA significantly reduced the expression of TNF-α, iNOS, and caspase-3 as compared with the ischemia group. In molecular docking study, CGA displayed similar binding interaction as that of Ifenprodil and 7-nitroindazole with NMDAR and nNOS respectively. The current findings suggest that the treatment with CGA confers neuroprotection in global ischemic insult by inhibiting and downregulating the different molecular markers of cerebral ischemia.

Pharmacokinetics and brain penetration study of chlorogenic acid in rats.

1. The present study is designed to investigate the brain distribution and plasma pharmacokinetics profiles of chlorogenic acid (CGA) after intranasal administration in Charles-Foster rats to evaluate whether the CGA molecules are transported directly via the nose-to-brain path. 2. The CGA is administered intravenously (IV) and intranasally (IN) at the dose of 10 mg/kg. Further, its concentration in the plasma, cerebrospinal fluid (CSF) and the whole brain is analyzed by HPLC-UV method. 3. The study observes that CGA is rapidly absorbed in plasma with tmax of 1 min similar to IV route after IN administration. The peak plasma concentration and AUC0-24 are higher by 3.5 and 4.0 times respectively in IV administration, compared to IN delivery that represents the significant less systemic exposure of CGA in IN route. 4. However, the concentration of CGA in the brain is 4, 6.5, 5.3, 5.2 and 4.5 times higher at 30, 60, 120, 240 and 360 min, respectively in IN administration compared to IV administration. The exposure of CGA in the brain after IN administration (AUCbrain, IN) was significantly greater (4 times) as compared to the exposure of CGA in the brain (AUCbrain, IV) after IV administration reflecting significant brain uptake of CGA through nasal route. Therefore, IN delivery of CGA can be a promising approach for the treatment of stroke and neurodegenerative disorders.

Nanoparticle-Induced Controlled Drug Delivery Using Chitosan-Based Hydrogel and Scaffold: Application to Bone Regeneration.

The novel chitosan nanohybrid hydrogel and scaffold have been developed with high mechanical strength and tailor the drug release ability for their applications in the biomedical arena. Nanohybrid hydrogels are prepared in dilute acetic acid medium using two different types of two-dimensional-layered nanoparticles. Scaffolds are prepared through lyophilization of hydrogels. Highly porous, open, and 3D interconnected morphologies are observed in the nanohybrid scaffolds, as opposed to the thick wall, smaller pore dimension in pure chitosan. The interaction between the nanoparticles and chitosan chains are elucidated using different spectroscopic techniques, which in turn are responsible for the uniform distribution of the nanoparticle in the chitosan matrix. Nanohybrids are found to be highly mechanically stable in both states (hydrogel and scaffold), as compared to pure chitosan because of the good reinforcing ability of 2D nanoparticles. Sustained drug release has been achieved in nanohybrid in vitro, as compared to the pure chitosan hydrogel/scaffold, mainly due to greater interactions between the components and the better barrier effect of 2D nanoparticles. Cytotoxicity of the nanohybrids is verified using NIH 3T3 mouse embryonic fibroblast cells for their possible use as controlled drug delivery vehicles. Nanohybrids are found to be nontoxic in nature and more biocompatible as compared to pure chitosan, as observed through cell viability and cell imaging studies. Interestingly, cell growth occurs within the pores of the nanohybrid scaffold, vis-à-vis the surface proliferation noticed in the pure chitosan scaffold. Better biocompatibility, hydrophilic nature, and sustained delivery with location specific cell growth make this nanohybrid hydrogel unique for biomedical uses. The bone regeneration rate is found to be significantly higher for the nanohybrid scaffold as compared to blank/pure chitosan without any side effect, suggesting nanohybrid systems are superior biomaterials.

Pharmacological application of barium containing bioactive glass in gastro-duodenal ulcers.

Peptic ulcer is prevalent in about 4% of the world population and nearly 10% of people have been affected by peptic ulcer at some point in their life. Therefore, there is a need for newer efficient and safe anti-ulcer agents. In the present strategy, we have prepared a novel bioactive glass containing 1.3 mol% of barium oxide (BaBG) and evaluated its antiulcer potential in gastroduodenal ulcer models. Prophylactic effect of BaBG pretreatment was evaluated for 5 days in ethanol, aspirin and pyloric ligation-induced gastric ulcer and cysteamine-induced duodenal ulcer models. Repeated treatment of 10 days of BaBG was evaluated in the healing ulcer model of acetic acid. BaBG significantly reduced the ulcerative damage against all the five tested ulcer models. Scanning electron microscope (SEM) images have shown that BaBG forms a physical protective barrier over the gastro-duodenal epithelium cell. In the pyloric-ligation, ethanol and aspirin models, BaBG showed significantly increased in gastric pH, indicating antacid like activity. BaBG treatment significantly increased cell proliferation in the pyloric model. Thus, BaBG mediates antiulcer action by forming a protective physical barrier against harsh luminal factors, acid neutralization and cell proliferation.

Indole-3-carbinol improves neurobehavioral symptoms in a cerebral ischemic stroke model.

Stroke is one of the most common causes of death worldwide and also responsible for permanent disability. Ischemic stroke has been found to affect 80% of stroke patients. Recombinant tissue plasminogen activator (rtPA) is the widely used drug for the ischemic stroke with narrow therapeutic window. Indole-3-carbinol (I3C) is a natural compound obtained from brassica species having antithrombotic activity. Middle cerebral artery occlusion (MCAO) model was used followed by reperfusion after 2 h of ischemia for the evaluation of the I3C against ischemic stroke. After reperfusion, I3C (12.5, 25, and 50 mg/kg) was given by oral route once daily and continued up to the 14th day. Behavioral studies including postural reflex, forelimb placing, and cylinder tests showed I3C attenuated the MCAO-induced increase in average score and asymmetry score efficiently. Mean cerebral blood flow (CBF) was improved by treatment with I3C (12.5 mg/kg) by 60% of baseline at 6 h. I3C inhibited ADP-induced platelet aggregation and reduced ischemic volume significantly. It also inhibited in vitro the ADP-induced platelet aggregation in healthy human volunteers. I3C improves behavioral scores and mean CBF after focal cerebral ischemia in rats. Furthermore, I3C showed prophylactic anti-thrombotic activity against carrageenan induced tail thrombosis. Therefore, preclinical evidence points to I3C as a potential candidate for use in cerebral ischemic stroke.

Pharmacokinetic Study of Piracetam in Focal Cerebral Ischemic Rats.

BACKGROUND AND OBJECTIVE: Cerebral ischemia affects hepatic enzymes and brain permeability extensively. Piracetam was investigated up to phase III of clinical trials and there is lack of data on brain penetration in cerebral ischemic condition. Thus, knowledge of the pharmacokinetics and brain penetration of piracetam during ischemic condition would aid to improve pharmacotherapeutics in ischemic stroke. METHODS: Focal cerebral ischemia was induced by middle cerebral artery occlusion for 2 h in male Wistar rats followed by reperfusion. After 24 h of middle cerebral artery occlusion or 22 h of reperfusion, piracetam was administered for pharmacokinetic, brain penetration, and pharmacological experiments. In pharmacokinetic study, blood samples were collected at different time points after 200-mg/kg (oral) and 75-mg/kg (intravenous) administration of piracetam through right external jugular vein cannulation. In brain penetration study, the cerebrospinal fluid, systemic blood, portal blood, and brain samples were collected at pre-designated time points after 200-mg/kg oral administration of piracetam. In a separate experiment, the pharmacological effect of the single oral dose of piracetam in middle cerebral artery occlusion was assessed at a dose of 200 mg/kg. RESULTS: All the pharmacokinetic parameters of piracetam including area under curve (AUC0-24), maximum plasma concentration (C max), time to reach the maximum plasma concentration (t max), elimination half-life (t 1/2), volume of distribution (V z), total body clearance, mean residence time, and bioavailability were found to be similar in ischemic stroke condition except for brain penetration. Piracetam exposure (AUC0-2) in brain and CSF were found to be 2.4- and 3.1-fold higher, respectively, in ischemic stroke compared to control rats. Piracetam significantly reduced infarct volume by 35.77% caused by middle cerebral artery occlusion. CONCLUSIONS: There was no change in the pharmacokinetic parameters of piracetam in the ischemic stroke model except for brain penetration. This indicates that variables influencing brain penetration may not be limiting factors for use of piracetam in ischemic stroke.

Piracetam Attenuates LPS-Induced Neuroinflammation and Cognitive Impairment in Rats.

The present study was performed to investigate the effect of piracetam on neuroinflammation induced by lipopolysaccharide (LPS) and resulting changes in cognitive behavior. Neuroinflammation was induced by a single dose of LPS solution infused into each of the lateral cerebral ventricles in concentrations of 1 µg/µl, at a rate of 1 µl/min over a 5-min period, with a 5-min waiting period between the two infusions. Piracetam in doses of 50, 100, and 200 mg/kg i.p. was administered 30 min before LPS infusion and continued for 9 days. On ninth day, the behavioral test for memory and anxiety was done followed by blood collection and microdissection of the hippocampus (HIP) and prefrontal cortex brain regions. Piracetam attenuated the LPS-induced decrease in coping strategy to novel environment indicating anxiolytic activity. It also reversed the LPS-induced changes in the known arm and novel arm entries in the Y-maze test indicating amelioration of spatial memory impairment. Further, piracetam moderated LPS-induced decrease in the mitochondrial complex enzyme activities (I, II, IV, and V) and mitochondrial membrane potential. It ameliorated changes in hippocampal lipid peroxidation and nitrite levels including the activity of superoxide dismutase. Piracetam region specifically ameliorated LPS-induced increase in the level of IL-6 in HIP indicating anti-neuroinflammatory effect. Further, piracetam reduced HIP Aß (1-40) and increased blood Aß level suggesting efflux of Aß from HIP to blood. Therefore, the present study indicates preclinical evidence for the use of piracetam in the treatment of neuroinflammatory disorders.