The synergic effects of presynaptic calcium channel antagonists purified from spiders on memory elimination of glutamate-induced excitotoxicity in the rat hippocampus trisynaptic circuit.

The hippocampus is a complex area of the mammalian brain and is responsible for learning and memory. The trisynaptic circuit engages with explicit memory. Hippocampal neurons express two types of presynaptic voltage-gated calcium channels (VGCCs) comprising N and P/Q-types. These VGCCs play a vital role in the release of neurotransmitters from presynaptic neurons. The chief excitatory neurotransmitter at these synapses is glutamate. Glutamate has an essential function in learning and memory under normal conditions. The release of neurotransmitters depends on the activity of presynaptic VGCCs. Excessive glutamate activity, due to either excessive release or insufficient uptake from the synapse, leads to a condition called excitotoxicity. This pathological state is common among all neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Under these conditions, glutamate adversely affects the trisynaptic circuitry, leading to synaptic destruction and loss of memory and learning performance. This study attempts to clarify the role of presynaptic VGCCs in memory performance and reveals that modulating the activity of presynaptic calcium channels in the trisynaptic pathway can regulate the excitotoxic state and consequently prevent the elimination of neurons and synaptic degradation. All of these can lead to an improvement in learning and memory function. In the current study, two calcium channel blockers-omega-agatoxin-Aa2a and omega-Lsp-IA-were extracted, purified, and identified from spiders (Agelena orientalis and Hogna radiata) and used to modulate N and P/Q VGCCs. The effect of omega-agatoxin-Aa2a and omega-Lsp-IA on glutamate-induced excitotoxicity in rats was evaluated using the Morris water maze task as a behavioral test. The local expression of synaptophysin (SYN) was visualized for synaptic quantification using an immunofluorescence assay. The electrophysiological amplitudes of the field excitatory postsynaptic potentials (fEPSPs) in the input-output and LTP curves of the mossy fiber and Schaffer collateral circuits were recorded. The results of our study demonstrated that N and P/Q VGCC modulation in the hippocampus trisynaptic circuit of rats with glutamate-induced excitotoxicity dysfunction could prevent the destructive consequences of excitotoxicity in synapses and improve memory function and performance.

Purified Native Protein Extracted from the Venom of Agelena orientalis Attenuates Memory Defects in the Rat Model of Glutamate-Induced Excitotoxicity.

Spider venom contains various peptides and proteins, which can be used for pharmacological applications. Finding novel therapeutic strategies against neurodegenerative diseases with the use of purified peptides and proteins, extracted from spiders can be greatly precious. Neurodegenerative diseases are rapidly developing and expanding all over the world. Excitotoxicity is a frequent condition amongst neuro-degenerative disorders. This harmful process is usually induced through hyper-activation of N-Methyl-D-Aspartate (NMDA) receptor, and P/Q-type voltage-gated calcium channels (VGCCs). The omega-agatoxin-Aa4b is a selective and strong VGCCblocker. This study aimed to investigate the effects of this blocker on the NMDA-induced memory and learning defect in rats. For this purpose, nineteen spiders of the funnel-weaver Agelena orientalis species were collected. The extracted venom was lyophilized andpurified through gel-filtration chromatography, and capillary electrophoresis techniques. Subsequently, mass spectrometry (HPLC-ESI-MS) was used for identification of this bio-active small protein. Afterward, the effect of the omega-agatoxin-Aa4b (2 µg, intra-cornu ammonis-3 of the hippocampus) on the NMDA-induced learning and memory deficits in rats was evaluated. Learning and memory performances were evaluated by the use of passive avoidance test. For synaptic quantification and memory function the amount of calcium/calmodulin-dependent protein kinase ІІ (CaCdPKІІ) gene expression was measured using the Real-time PCR technique. To compare the experimental groups, hematoxylin and eosin (H&E) staining of hippocampus tissues was performed. Our results rendered that the omega-Agatoxin-Aa4b treatment can ameliorate and reverse the learning and memory impairment caused by NMDA-induced excitotoxicity in rat hippocampus.

Corrigendum: Alleviation of cognitive deficits in a rat model of glutamate-induced excitotoxicity, using an N-type voltage-gated calcium channel ligand, extracted from Agelena labyrinthica crude venom.

[This corrects the article DOI: 10.3389/fnmol.2023.1123343.].

Alleviation of cognitive deficits in a rat model of glutamate-induced excitotoxicity, using an N-type voltage-gated calcium channel ligand, extracted from Agelena labyrinthica crude venom.

Excitotoxicity is a common pathological process in Alzheimer's disease (AD) which is caused by the over-activity of N-Methyl-D-Aspartate receptors (NMDARs). The release of neurotransmitters depends on the activity of voltage-gated calcium channels (VGCCs). Hyper-stimulation of NMDARs can enhance the releasement of neurotransmitters through the VGCCs. This malfunction of channels can be blocked by selective and potent N-type VGCCs ligand. Under excitotoxicity condition, glutamate has negative effects on the pyramidal cells of the hippocampus, which ends in synaptic loss and elimination of these cells. These events leads to learning and memory elimination through the hippocampus circuit's dysfunction. A suitable ligand has a high affinity to receptor or channel and is selective for its target. The bioactive small proteins of venom have these characteristics. Therefore, peptides and small proteins of animal venom are precious sources for pharmacological applications. The omega-agatoxin-Aa2a was purified, and identified from Agelena labyrinthica specimens, as an N-type VGCCs ligand for this study. The effect of the omega-agatoxin-Aa2a on the glutamate-induced excitotoxicity in rats was evaluated through behavioral tests including Morris Water Maze, and Passive avoidance. The syntaxin1A (SY1A), synaptotagmin1 (SYT1), and synaptophysin (SYN) genes expression were measured via Real-Time PCR. The local expression of synaptosomal-associated protein, 25 k Da (SNAP-25) was visualized using an immunofluorescence assay for synaptic quantification. Electrophysiological amplitude of field excitatory postsynaptic potentials (fEPSPs) in the input-output and LTP curves of mossy fiber were recorded. The cresyl violet staining of hippocampus sections was performed for the groups. Our results demonstrated that the omega-agatoxin-Aa2a treatment could recover the learning, and memory impairment caused by NMDA-induced excitotoxicity in rat hippocampus.

Cost-effectiveness and cost-utility analysis of type-2 diabetes screening in pharmacies in Iran.

Background and purpose: Several studies have shown the effectiveness of screening programs in decreasing the costs and disutility of type-2 diabetes and related complications. As there is a growth in the incidence of type-2 diabetes amongst the Iranian population, the cost-effectiveness of performing type-2 diabetes screening tests in community pharmacies of Iran was evaluated in this study from the payer's perspective. The target population consisted of two hypothetical cohorts of 1000 people 40 years of age without a prior diagnosis of diabetes, for the intervention (screening test) and no-screening groups. Experimental approach: A Markov model was developed to evaluate the cost-effectiveness and cost-utility of a type-2 diabetes screening test in community pharmacies in Iran. A 30-year time horizon was considered in the model. Three screening programs with 5-year intervals were considered for the intervention group. The evaluated outcomes were quality-adjusted life-years (QALYs) for cost-utility-analysis and life-years-gained (LYG) for cost-effectiveness-analysis. To examine the robustness of the results, one-way and probabilistic-sensitivity analyses were applied to the model. Findings/Results: The screening test represented both more effects and higher costs. The incremental effects in the base-case scenario (no-discounting) were estimated to be 0.017 and 0.0004 (approximately 0) for QALYs and LYG, respectively. The incremental cost was estimated to be 2.87 USD/patient. The estimated incremental-cost-effectiveness ratio was 164.77 USD/QALY. Conclusion and implications: This study indicated that screening for type-2 diabetes in community pharmacies of Iran could be considered highly cost-effective, as it meets the WHO criteria of the annual GDP per capita ($2757 in 2020).

Cost of Illness of Multiple Sclerosis in Isfahan, Iran, From a Social Perspective: A Comparison of the Human-Capital and Friction-Cost Methods.

OBJECTIVES: Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system that is characterized by demyelination and neurodegenerative changes and associated with high levels of disability. This study aimed to investigate direct and indirect costs of illness of patients with MS in Isfahan using and comparing human-capital and friction-cost methods from a societal perspective. METHODS: A total of 300 patients with MS of 2 main centers of the disease in Isfahan, the MS center of Ayatollah Kashani hospital and Isfahan MS center, were included. Patient's demographic characteristics, disease information, and annual social costs (2018-2019) were collected using data collection form. Both the human-capital and friction-cost methods were applied and compared with value indirect costs because of loss of productivity. RESULTS: From the social perspective, the average annual total cost of MS disease was estimated to be 1 441 163 710 rials (34 313 US dollar [USD]) per patient using the human-capital approach and 1 434 832 004 rials (34 162 USD) with the use of friction-cost method, from which 1 428 668 396 rials (34 016 USD) was related to direct costs. The main direct costs were related to disease-modifying therapies and referring to other physicians and hospitals. The cost of loss of production was greater with human-capital approach in comparison with friction-cost method. CONCLUSIONS: The most prominent cost in MS disease is related to drug costs. The indirect costs were sensitive to the methods, applied in the study.

Ameliorative effects of omega-lycotoxin-Gsp2671e purified from the spider venom of Lycosa praegrandis on memory deficits of glutamate-induced excitotoxicity rat model.

Memory impairment is one of the main complications of Alzheimer's disease (AD). This condition can be induced by hyper-stimulation of N-Methyl-D-aspartate receptors (NMDARs) of glutamate in the hippocampus, which ends up to pyramidal neurons determination. The release of neurotransmitters relies on voltage-gated calcium channels (VGCCs) such as P/Q-types. Omega-lycotoxin-Gsp2671e (OLG1e) is a P/Q-type VGCC modulator with high affinity and selectivity. This bio-active small protein was purified and identified from the Lycosa praegrandis venom. The effect of this state-dependent low molecular weight P/Q-type calcium modulator on rats was investigated via glutamate-induced excitotoxicity by N-Methyl-D-aspartate. Also, Electrophysiological amplitude of field excitatory postsynaptic potentials (fEPSPs) in the input-output and Long-term potentiation (LTP) curves were recorded in mossy fiber and the amount of synaptophysin (SYN), synaptosomal-associated protein, 25 kDa (SNAP-25), and synaptotagmin 1(SYT1) genes expression were measured using Real-time PCR technique for synaptic quantification. The outcomes of the current study suggest that OLG1e as a P/Q-type VGCC modulator has an ameliorative effect on excitotoxicity-induced memory defects and prevents the impairment of pyramidal neurons in the rat hippocampus.

Cost-Effectiveness and Cost-Utility Analysis of the Use of Clopidogrel and Pantoprazole in Comparison with Clopidogrel and Omeprazole for the Secondary Prevention of Myocardial Infarction in Iran.

OBJECTIVE: Gastrointestinal bleeding, a side effect of clopidogrel, is usually prevented by proton-pump inhibitors (PPIs). Due to omeprazole's inhibitory effects on the liver enzyme CYP2C19, its concomitant use with clopidogrel is argued to increase the risk of myocardial infarction (MI) recurrence, as CYP2C19 activates clopidogrel. Pantoprazole as an alternative PPI has shown no inhibitory effect on CYP2C19. This study investigates the cost-effectiveness of concomitant use of clopidogrel and pantoprazole in MI patients compared to the simultaneous use of clopidogrel and omeprazole. METHODS: We used the Markov-modeling technique with a hypothetical cohort of 1000 acute MI patients aged 55 years using Microsoft Excel 2013 software. The study was done from the payer perspective, and a lifetime horizon with 1-year cycles was considered in the model. Life-years gained (LYG) and quality-adjusted life-years (QALYs) were used to quantify the health effects of these interventions. Two separate scenarios of public tariffs and private tariffs with various discount rates (0%, 3%, and 7.2% discounts (only for costs)) were evaluated, and an incremental cost-effectiveness ratio (ICER) was used to report the results. One-way and probabilistic sensitivity analyses were used to deal with uncertainty. Data were sourced from published literature and tariff book of the Iranian ministry of health. FINDINGS: The estimated ICERs were 342 USD/QALY and 236 USD/LYG per patient for the base-case scenario. CONCLUSION: Abiding by the WHO threshold for cost-effectiveness, the concomitant use of pantoprazole and clopidogrel can be considered cost-effective compared to the use of omeprazole and clopidogrel.

The cost-effectiveness and cost-utility analysis of the use of enoxaparin compared with heparin for venous thromboembolism prophylaxis in medical inpatients in Iran.

BACKGROUND: Moderate to high risk medical inpatients are at increased risk of Venous Thromboembolism (VTE). The present study aims to investigate the cost-effectiveness and cost-utility of using Enoxaparin compared to Heparin in VTE prophylaxis in medical inpatients, from Iranian payer's perspective. METHODS: Decision tree modeling technique was used to evaluate cost-effectiveness and cost-utility of the compared interventions. The main considered outcomes were Life Years Gained (LYG) for Cost-Effectiveness Analysis (CEA) and Quality-Adjusted Life Years (QALY) for Cost-Utility Analysis (CUA). Costs and consequences of the interventions were evaluated for a three-month period and reported as Incremental Cost-Effectiveness Ratios (ICERs). One-way and Probabilistic Sensitivity Analysis (PSA) were conducted to evaluate the robustness of the model due to uncertainty in the input data. RESULTS: In base case scenario (i.e. public tariff), incremental cost was $10.32, and incremental QALY and incremental LYG were 0.0001 and 0.0002 per patients respectively. Base case ICERs were 60,376 USD/QALY and 71,077 USD/LYG per patient. The results of the sensitivity analysis showed the robustness of the model. CONCLUSION: As the estimated ICER per QALY is more than three times the reported Gross Domestic Product (GDP) per capita by world bank for Iran in 2017 ($5415), the use of Enoxaparin for VTE prophylaxis in medical in patients doesn't seem to be a cost-effective intervention compared to the use of Heparin in Iran.

Cost-effectiveness evaluation of aspirin in primary prevention of myocardial infarction amongst males with average cardiovascular risk in Iran.

Aspirin is one of the certified medicines commonly used for the secondary prevention of myocardial infarction (MI). Aspirin side effects and gastrointestinal bleeding, in particular, have arisen debates on its use for the primary prevention of MI. The present research evaluates the cost-effectiveness of the use of aspirin in the primary prevention of MI among Iranian men with average cardiovascular disease (CVD) risk, using Markov modeling technique. The incremental cost-effectiveness ratios (ICERs) estimated to be 864 USA dollars (USD) per quality-adjusted life years (QALY) gained and 782 USD per life years gained (LYG) for each patient in the base-case scenario (public tariffs and no discounting). This research proves cost-effectiveness of the use of aspirin in the primary prevention of MI in targeted population, since the assessed ICERs are quite under the recommended threshold by WHO which is one gross domestic product (GDP) per capita ($5315.1 for Iran in 2015).

Cost-effectiveness of surgical excision versus Mohs micrographic surgery for nonmelanoma skin cancer: A retrospective cohort study.

BACKGROUND: Nonmelanoma skin cancer rates are increasing worldwide. Mohs micrographic surgery and surgical excision (SE) are the two treatment methods for this type of cancer. The current paper aims at determining and comparing the cost-effectiveness of SE and Mohs micrographic surgery. MATERIALS AND METHODS: The current study has a retrospective cohort design. A number of 630 patients suffering from nonmelanoma skin cancer who at some point of time during the years 2007-2014 referred to the Al-Zahra or Seyed Al-Shohada Hospitals in Isfahan. Patients were followed up for 4 years, and then the incremental cost-effectiveness ratio (ICER) of the two methods was calculated. RESULTS: The average (minimum-maximum) cost of the SE and Mohs surgery methods in Iran was obtained as 18,550,170 (2335,800-260,898,262) and 12,236,890 (6488,340-41,161,700) Iranian Rial, respectively. Recurrence percentage was also reported as 7.9% and 8.7% for SE and Mohs micrographic surgery, respectively (P > 0.05). The ICER of SE in comparison with Mohs surgery was calculated as 7891,600 Iranian Rials per recurrence avoided. CONCLUSION: Mohs surgery is less expensive than SE, it seems like Mohs surgery is more affordable, however further studies in different populations of the country are needed.

Cost-effectiveness and cost-utility analysis of OTC use of simvastatin 10 mg for the primary prevention of myocardial infarction in Iranian men.

BACKGROUND: Several clinical trials and meta-analyses have shown the advantageous effects of statins in populations with different levels of cardiovascular disease (CVD) risk. Considering the increasing cardiovascular risk among the Iranian population, the cost-effectiveness of the use of simvastatin 10 mg, as an Over-The-Counter (OTC) drug, for the primary prevention of myocardial infarction (MI) was evaluated in this modeling study, from the payer's perspective. The target population is a hypothetical cohort of 45-year CVD healthy men with an average (15%) 10-year CVD risk. METHODS: A semi-Markov model with a life-long time horizon was developed to evaluate the Cost-Utility-Analysis (CUA) and Cost-Effectiveness-Analysis (CEA) of the use of OTC simvastatin 10 mg compared to no-drug therapy. Two measures of benefits were used in the model; Quality-Adjusted-Life-Years (QALYs) for the CUA and Life-Years-Gained (LYG) for the CEA. To examine the robustness of the results, one-way sensitivity analysis and probabilistic sensitivity analysis were applied to the model. RESULTS: For the base-case scenario with a discount rate of 0% the estimated ICERs were 1113 USD/QALY and 935USD/LYG per patient (using governmental tariffs). No threshold has been determined in Iran for the cost-effectiveness of health-related interventions. However, according to the recommendation of WHO, this intervention can be considered highly cost-effective as its ICER is far less than the reported GDP per capita for Iran by World bank in 2013 ($4763). CONCLUSIONS: This modeling study showed that the use of an OTC low dose statin (simvastatin 10 mg) for the primary prevention of myocardial infarction (MI) in 45-year men with a 10-year CVD risk of 15% could be considered highly cost-effective in Iran, as it meets the WHO threshold of the annual GDP per capita ($4763).