Comparative Effect of Lisinopril and Fosinopril in Mitigating Learning and Memory Deficit in Scopolamine-Induced Amnesic Rats

Modeling Path Importance for Effective Alzheimer's Disease Drug Repurposing

Recently, drug repurposing has emerged as an effective and resource-efficient paradigm for AD drug discovery. Among various methods for drug repurposing, network-based methods have shown promising results as they are capable of leveraging complex networks that integrate multiple interaction types, such as protein-protein interactions, to more effectively identify candidate drugs. However, existing approaches typically assume paths of the same length in the network have equal importance in identifying the therapeutic effect of drugs. Other domains have found that same length paths do not necessarily have the same importance. Thus, relying on this assumption may be deleterious to drug repurposing attempts. In this work, we propose MPI (Modeling Path Importance), a novel network-based method for AD drug repurposing. MPI is unique in that it prioritizes important paths via learned node embeddings, which can effectively capture a network's rich structural information. Thus, leveraging learned embeddings allows MPI to effectively differentiate the importance among paths. We evaluate MPI against a commonly used baseline method that identifies anti-AD drug candidates primarily based on the shortest paths between drugs and AD in the network. We observe that among the top-50 ranked drugs, MPI prioritizes 20.0% more drugs with anti-AD evidence compared to the baseline. Finally, Cox proportional-hazard models produced from insurance claims data aid us in identifying the use of etodolac, nicotine, and BBB-crossing ACE-INHs as having a reduced risk of AD, suggesting such drugs may be viable candidates for repurposing and should be explored further in future studies.

Modeling Path Importance for Effective Alzheimer's Disease Drug Repurposing

Recently, drug repurposing has emerged as an effective and resource-efficient paradigm for AD drug discovery. Among various methods for drug repurposing, network-based methods have shown promising results as they are capable of leveraging complex networks that integrate multiple interaction types, such as protein-protein interactions, to more effectively identify candidate drugs. However, existing approaches typically assume paths of the same length in the network have equal importance in identifying the therapeutic effect of drugs. Other domains have found that same length paths do not necessarily have the same importance. Thus, relying on this assumption may be deleterious to drug repurposing attempts. In this work, we propose MPI (Modeling Path Importance), a novel network-based method for AD drug repurposing. MPI is unique in that it prioritizes important paths via learned node embeddings, which can effectively capture a network's rich structural information. Thus, leveraging learned embeddings allows MPI to effectively differentiate the importance among paths. We evaluate MPI against a commonly used baseline method that identifies anti-AD drug candidates primarily based on the shortest paths between drugs and AD in the network. We observe that among the top-50 ranked drugs, MPI prioritizes 20.0% more drugs with anti-AD evidence compared to the baseline. Finally, Cox proportional-hazard models produced from insurance claims data aid us in identifying the use of etodolac, nicotine, and BBB-crossing ACE-INHs as having a reduced risk of AD, suggesting such drugs may be viable candidates for repurposing and should be explored further in future studies.

Vitamin D3 supplementation ameliorates cognitive impairment and alters neurodegenerative and inflammatory markers in scopolamine induced rat model

A multifaceted approach can be effective for the treatment of dementia including the most common form, Alzheimer's disease (AD). However, currently, it involves only symptomatic treatment with cholinergic drugs. Beneficial effects of high Vitamin D₃ levels or its intake in the prevention and treatment of cognitive disorders have been reported. Thus, the present study examined the preventive effect of Vitamin D₃ (Calcitriol) supplementation on cognitive impairment and evaluated its impact on the accumulation or degradation of Aβ plaques. A single intraperitoneal injection of scopolamine was used to induce cognitive impairment in rats. Treatment of Vitamin D₃ was provided for 21 days after the injection. Various behavioral parameters like learning, spatial memory and exploratory behavior, biochemical alterations in the brain homogenate and histology of the hippocampus were investigated. Our results indicated that scopolamine-induced rats depicted cognitive deficits with high Aβ levels and hyperphosphorylated tau proteins in the brain tissue, while Vitamin D supplementation could significantly improve the cognitive status and lower these protein levels. These results were supported by the histopathological and immunohistochemical staining of the hippocampal brain region. Furthermore, mechanistic analysis depicted that Vitamin D supplementation improved the Aβ protein clearance by increasing the neprilysin levels. It also reduced the accumulation of Aβ plaques by lowering neuroinflammation as well as oxidative stress. The present findings indicate that Vitamin D₃ supplementation can ameliorate cognitive deficits and thereby delay AD progression by increasing Aβ plaque degradation, reducing inflammation and oxidative stress.

Insights of Valacyclovir in Treatment of Alzheimer's Disease: Computational Docking Studies and Scopolamine Rat Model

BACKGROUND

Alzheimer's Disease (AD) impairs memory and cognitive functions in the geriatric population and is characterized by intracellular deposition of neurofibrillary tangles, extracellular deposition of amyloid plaques, and neuronal degeneration. Literature suggests that latent viral infections in the brain act as prions and promote neurodegeneration. Memantine possesses both anti-viral and N-methyl-D-aspartate (NMDA) receptor antagonistic activity.

OBJECTIVES

This research was designed to evaluate the efficacy of antiviral agents, especially valacyclovir, a prodrug of acyclovir in ameliorating the pathology of AD based on the presumption that anti-viral agents targeting the Herpes Simplex Virus (HSV) can have a protective effect on neurodegenerative diseases like Alzheimer's disease.

METHODS

Thus, we evaluated acyclovir's potential activity by in-silico computational docking studies against acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and beta-secretase 1 (BACE-1). These findings were further evaluated by in-vivo scopolamine-induced cognitive impairment in rats. Two doses of valacyclovir, a prodrug of acyclovir (100 mg/kg and 150 mg/kg orally) were tested.

RESULTS

Genetic Optimisation for Ligand Docking scores and fitness scores of acyclovir were comparable to donepezil. Valacyclovir improved neurobehavioral markers. It inhibited AChE and BuChE (p<0.001) enzymes. It also possessed disease-modifying efficacy as it decreased the levels of BACE-1 (p<0.001), amyloid beta 1-42 (p<0.001), amyloid beta 1-40 (p<0.001), phosphorylatedtau (p<0.001), neprilysin (p<0.01), and insulin-degrading enzyme. It ameliorated neuroinflammation through decreased levels of tumour necrosis factor α (p<0.001), nuclear factor-kappa B (p<0.001), interleukin 6 (p<0.001), interleukin 1 beta (p<0.001), and interferon-gamma (p<0.001). It also maintained synaptic plasticity and consolidated memory. Histopathology showed that valacyclovir could restore cellular density and also preserve the dentate gyrus.

CONCLUSION

Valacyclovir showed comparable activity to donepezil and thus can be further researched for the treatment of Alzheimer's disease.

Recent Advances in the Endogenous Brain Renin-Angiotensin System and Drugs Acting on It

The RAS (renin-angiotensin system) is the part of the endocrine system that plays a prime role in the control of essential hypertension. Since the discovery of brain RAS in the seventies, continuous efforts have been put by the scientific committee to explore it more. The brain has shown the presence of various components of brain RAS such as angiotensinogen (AGT), converting enzymes, angiotensin (Ang), and specific receptors (ATR). AGT acts as the precursor molecule for Ang peptides—I, II, III, and IV—while the enzymes such as prorenin, ACE, and aminopeptidases A and N synthesize it. AT1, AT2, AT4, and mitochondrial assembly receptor (MasR) are found to be plentiful in the brain. The brain RAS system exhibits pleiotropic properties such as neuroprotection and cognition along with regulation of blood pressure, CVS homeostasis, thirst and salt appetite, stress, depression, alcohol addiction, and pain modulation. The molecules acting through RAS predominantly ARBs and ACEI are found to be effective in various ongoing and completed clinical trials related to cognition, memory, Alzheimer's disease (AD), and pain. The review summarizes the recent advances in the brain RAS system highlighting its significance in pathophysiology and treatment of the central nervous system-related disorders.

Anti-oxidant impact of Lisinopril and Enalapril against acute kidney injury induced by doxorubicin in male Wistar rats: involvement of kidney injury molecule-1

Doxorubicin (DOX) is a standard anticancer agent exerting devastating effects as nephrotoxicity, hepatotoxicity and cardiotoxicity. The purpose of this study was to increase the clinical use of DOX through decreasing its detrimental effects via combination with ACE inhibitors to ameliorate the induced acute kidney injury (AKI). AKI was induced by a single injection of DOX (7.5 mg/kg; i.p.) as Group 1; control (vehicle), Group 2; DOX (7.5 mg/kg; i.p.) single dose, Group 3 and 4; Lisinopril (Lis, 20 mg/kg) and Enalapril (Enal, 40 mg/kg) orally administration for 15 consecutive days after DOX injection, respectively. Serum samples were used to measure creatinine and BUN, tissue samples were extracted to determine myeloperoxidase (MPO), malondialdehyde (MDA), total antioxidant capacity (TAC) and kidney injury molecule (KIM-1) using ELISA technique. Heme oxygenase (HO-1) RNA expression was quantified in tissue using real time polymerase chain reaction (PCR). Parts of the kidney tissue were kept in formalin for immunohistochemical demonstration of Cleaved Caspase-3 and NF-κβ immune staining and the other part was used for pathological examination. Oral treatment with Lis (20 mg/kg) and Enal (40 mg/kg) for 15 consecutive days reversed DOX effects as they reduced the serum creatinine and BUN, kidney levels of MPO and MDA, whereas the drugs increased tissue TAC. The administration of Lis and Enal with DOX also reduced KIM-1and HO-1 RNA expression. A significant decrease in cleaved caspase-3 and NF-κβ immunostainings in conjunction with pronounced amelioration in pathologies in the rat kidney were observed. We concluded that DOX adverse effects can be controlled by Lis and Enal.

Telmisartan/17β-estradiol mitigated cognitive deficit in an ovariectomized rat model of Alzheimer's disease: Modulation of ACE1/ACE2 and AT1/AT2 ratio

AIMS

The higher incidence rate of Alzheimer's disease (AD) among women has led to explorations on the association between estrogen deficiency and AD. Also, usage of antihypertensive drugs has been suggested to reduce the incidence of AD in elderly hypertensive patients. Thus, this study aimed to investigate the effects of telmisartan and/or 17β-estradiol on a cognitively impaired ovariectomized rat model of AD.

MAIN METHODS

75 female Wistar rats were randomly allocated into five groups. One group was sham operated and the other four groups were subjected to ovariectomy, received D-galactose and either untreated or treated with telmisartan and/or 17β-estradiol for 6 weeks.

KEY FINDINGS

Ovariectomized rats showed cognitive impairment in Morris water maze and novel object recognition tests, increasing inflammatory biomarkers (tumor necrosis factor-α, and interleukin-1β), increasing AD biomarkers (amyloid beta1-42, and acetylcholine esterase), and over activation of classical arm of renin angiotensin system (RAS) (ACE1/Ang2/AT1) in hippocampi. Also, hippocampi histopathological examination revealed amyloid beta deposition. Whereas, administration of telmisartan and/or 17β-estradiol improved animals' behavior, alleviated histopathological alterations and reduced the level of inflammatory and AD biomarkers, modulated RAS activity favoring the novel neuroprotective arm (ACE2/Ang(1-7)/MasR).

SIGNIFICANCE

Our findings suggest that combined administration of both drugs has synergetic neuroprotective effects; supporting their potential application in AD treatment.

Effects of Euterpe oleracea to Enhance Learning and Memory in a Conditioned Nicotinic and Muscarinic Receptor Response Paradigm by Modulation of Cholinergic Mechanisms in Rats

Euterpe oleracea (EO) includes a large number of polyphenolic compounds such as phenolics, flavonoids, and anthocyanins that have antioxidant activities. E. oleracea was suggested to ease the oxidative stress and inflammation in brain cells. Our aim was to analyze the effects of E. oleracea on learning and memory. Seventy-two (250 ± 25 g) male Wistar albino rats were used for this study. The groups consisted of control, EO100 mg/kg, EO300 mg/kg, scopolamine 1.5 mg/kg, mecamylamine 7.5 mg/kg, combinations of scopolamine with EO100 mg/kg, EO300 mg/kg, and rivastigmine 1.5 mg/kg; and mecamylamine combined with EO100 mg/kg. Before the start of the study, E. oleracea doses were provided once a day for a period of 15 days and for a 6-day experimental period. Thirty minutes after intraperitoneal scopolamine and mecamylamine injections, gastrogavage was applied to each group. Ninety minutes after the drug treatments, locomotor activity and Morris water maze tests were performed. Rats were killed and each hippocampus was used for the quantification of acetylcholine (Ach). Statistical analyses were calculated using one-way and two-way analyses of variance (ANOVA), and a value of P < .05 was considered significant. In groups EO100 mg/kg and EO300 mg/kg the results did not show any significant changes on learning and memory compared with the control group. Mecamylamine and scopolamine enhanced the latency for the escape platform, and decreased the time spent in escape platform quadrant when the memory tests were applied in reference to the control value of P < .05. Scopolamine and mecamylamine combinations of EO100 mg/kg, EO300 mg/kg, and rivastigmine were proven to improve the memory. There was significant difference between the first and fifth days of the learning tests in all the groups, but no significant difference occurred between the groups. Ach levels in hippocampi supported all memory tests. We suggest that E. oleracea made no alterations on learning and memory, but still improved nicotinic and muscarinic receptor-mediated and impaired memory just as rivastigmine.

Evaluation of antiamnesic activity of Salvia multicaulis essential oil on scopolamine-induced amnesia in rats: in vivo and in silico approaches

Plants of genus Salvia have been used in folk medicine for wound healing, in the alleviation of stomach, liver, and rheumatism pains, as antioxidant, cognitive-enhancer, sedative and antiseptic, stimulant and tonic agents. The present study aimed to evaluate whether Salvia multicaulis essential oil (1% and 3%) administered for 21 days attenuates cognitive deficits and exhibits anxiolytic and antidepressant-profile in the scopolamine-induced amnesia in rats. Rats were randomly divided into six groups (n = 6): (1) control, (2) scopolamine (Sco, 0.7 mg/kg) (3, 4) S. multicaulis essential oil treatment groups (SEO, 1% and 3%), (5) diazepam (DIAZ, 1.5 mg/kg) and (6) tramadol (TRM, 10 mg/kg). To establish an animal model of amnesia, Sco (0.7 mg/kg), a muscarinic acetylcholine receptor antagonist, was injected into male Wistar rats. Y-maze (memory), radial arm-maze (memory), elevated plus-maze (anxiety), and forced swimming (depression) tests were employed. Molecular interactions of chemical compounds from the essential oil with the GABA_A receptor was explored via molecular docking experiments. Using behavioral tests, we demonstrated that inhalation of S. multicaulis essential oil exerts significant antiamnesic activity as well as anxiolytic-antidepressant-like effects in the Sco-treated rats. Our data revealed that S. multicaulis oil could act as a promising phytopharmaceutical agent for improving dementia-related abnormalities.

HO-1 dependent antioxidant effects of ethyl acetate fraction from Physalis alkekengi fruit ameliorates scopolamine-induced cognitive impairments

Physalis alkekengi var. francheti is an indigenous herb well known for its anti-inflammatory, sedative, antipyretic, and expectorant properties. However, the information regarding the impacts of P. alkekengi fruits (PAF) in modulation of oxidative stress and learning memory are still unknown. This study therefore evaluated the antioxidant properties of ethyl acetate (EA) fraction of PAF and its impacts on learning and memory. The antioxidant activities of PAF were evaluated in LPS-induced BV2 microglial cells. The potent EA fraction then investigated and confirmed for its involvement of HO-1 pathway using hemin (HO-1 inducer) and ZnPP (HO-1 inhibitor) through Western blotting, DCFH-DA, and/or Griess assay. The involvements of PI3K/Akt, MEK, and p38 MAPK also investigated. Furthermore, we applied EA fraction to the animals at 100 and 200 mg/kg doses to check if the extract could improve scopolamine-induced memory deficits in passive avoidance and elevated plus maze tests. Our results demonstrated that the fractions from PAF significantly inhibited the generation of intracellular reactive oxygen species (ROS) induced by LPS in concentration-dependent manners. In comparison to other fractions, the EA fraction exhibited potent effect in suppressing intracellular ROS generation. Besides, EA fraction also induced the expression of HO-1 in time- and concentration-dependent manners. ZnPP significantly reversed the suppressive effect of EA fraction on LPS-induced ROS generation and NO production, which confirm the involvement of HO-1 signaling in EA-fraction-mediated antioxidant activities. Consistently, blocking of PI3K/Akt, MEK, and p38 MAPK pathways by PAF-EA suppressed the production of intracellular ROS, indicating their potential participation. In addition, one of the major constituents of EA fraction, luteolin-7-O-β-D-glucoside, also demonstrated HO-1-dependent antioxidant effects in BV2 cells. Further, the EA fraction significantly (p < 0.05) improves scopolamine-induced memory deficits in mice. Taken together, our findings highlight the antioxidant effects of EA fraction of PAF which may be beneficial in treatment of different neurodegenerative diseases associated with free radicals.

Anxiolytic-like effect of 2-(4-((1-phenyl-1H-pyrazol-4-yl)methyl)piperazin-1-yl)ethan-1-ol is mediated through the benzodiazepine and nicotinic pathways

In this study, we proposed the design, synthesis of a new compound 2-(4-((1-phenyl-1H-pyrazol-4-yl)methyl)piperazin-1-yl)ethan-1-ol (LQFM032), and pharmacological evaluation of its anxiolytic-like effect. This new compound was subjected to pharmacological screening referred to as Irwin test, prior to sodium pentobarbital-induced sleep, open-field and wire tests. The anxiolytic-like effect of this compound was evaluated using elevated plus maze and light-dark box tests. In addition, the mnemonic activity was evaluated through step-down test. In sodium pentobarbital-induced sleep test, LQFM032 decreased latency and increased duration of sleep. In the open-field test, LQFM032 altered behavioral parameter, that suggested anxiolytic-like activity, as increased in crossings and time spent at the center of open field. In the plus maze test and light-dark box test, the LQFM032 showed anxiolytic-like activity, increased entries and time spent on open arms, and increased in number of transitions and time spent on light area, respectively. Those effects was antagonized by flumazenil but not with 1-(2-Methoxyphenyl)-4-(4-phthalimidobutyl)piperazine (NAN-190). The LQFM032 did not alter mnemonic activity. Moreover, the anxiolytic-like activity of LQFM032 was antagonized by mecamylamine. In summary, LQFM032 showed benzodiazepine and nicotinic pathways mediated anxiolytic-like activity without altering the mnemonic activity.