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Roushdy MMS, Labib JMW, Abdelrahim DS, Mohamed DAW, Abdelmalak MFL. Amitriptyline and cholecalciferol amend hippocampal histological structure and myelination during stress in Wistar rats via regulating miR200/BMP4/Olig-2 signaling. Cell Biol Int 2024; 48:1326-1342. [PMID: 38890788 DOI: 10.1002/cbin.12200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/24/2024] [Accepted: 05/31/2024] [Indexed: 06/20/2024]
Abstract
Chronic stress is a universal condition commonly associated with many psychiatric diseases. An extensive body of evidence discussed hippocampal affection upon chronic stress exposure, however, the underlying molecular pathways still need to be identified. We investigated the impact of chronic stress on miR200/BMP/Olig-2 signaling and hippocampal myelination. We also compared the effects of chronic administration of amitriptyline and cholecalciferol on chronically stressed hippocampi. Both amitriptyline and cholecalciferol significantly decreased serum cortisol levels, reduced immobility time in the forced swim test, increased the number of crossed squares in open field test, decreased the hippocampal expression of bone morphogenetic protein 4 (BMP4) and its messenger RNA (mRNA) levels, reduced miR200 expression as compared to untreated chronically stressed rats. Also, both drugs amended the hippocampal neuronal damage, enhanced the surviving cell count, and increased the pyramidal layer thickness of Cornu Ammonis subregion 1 (CA1) and granule cell layer of the dentate gyrus. Cholecalciferol was more effective in increasing the area percentage of myelin basic protein (MBP) and Olig-2 positive cells count in hippocampi of chronic stress-exposed rats than amitriptyline, thus enhancing myelination. We also found a negative correlation between the expression of BMP4, its mRNA, miR200, and the immunoexpression of MBP and Olig-2 proteins. This work underscores the amelioration of the stress-induced behavioral changes, inhibition of miR200/BMP4 signaling, and enhancement of hippocampal myelination following chronic administration of either amitriptyline or cholecalciferol, though cholecalciferol seemed more effective in brain remyelination.
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Affiliation(s)
- Marian Maher Salib Roushdy
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Jolly M W Labib
- Department of Histology and Cell Biology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Dina Sayed Abdelrahim
- Department of Clinical Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
- Department of Pharmacology, Faculty of Medicine, Modern University for Technology and Information, Cairo, Egypt
| | - Dalia Abdel Wahab Mohamed
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Marian Farid Louka Abdelmalak
- Department of Clinical Pharmacology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
- Department of Pharmacology, Faculty of Medicine, Modern University for Technology and Information, Cairo, Egypt
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Moosavi M, Soukhaklari R, Bagheri-Mohammadi S, Firouzan B, Javadpour P, Ghasemi R. Nanocurcumin prevents memory impairment, hippocampal apoptosis, Akt and CaMKII-α signaling disruption in the central STZ model of Alzheimer's disease in rat. Behav Brain Res 2024; 471:115129. [PMID: 38942084 DOI: 10.1016/j.bbr.2024.115129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/16/2024] [Accepted: 06/24/2024] [Indexed: 06/30/2024]
Abstract
The central route of streptozotocin (STZ) administration has been introduced as a rat model of sporadic Alzheimer's disease (AD). Curcumin was suggested to possess possible neuroprotective effects, which may be profitable in AD. However, the low bioavailability of curcumin hinders its beneficial effects in clinical studies. Earlier studies suggested that a bovine serum albumin-based nanocurcumin, produces superior neuroprotective effects compared to natural curcumin. In the present study, the protective effect of nanocurcumin in rat model of central STZ induced memory impairment was assessed. In addition, due to the importance of the hippocampus in memory, the amounts of hippocampal active caspase-3, Akt, and CaMKII-α were evaluated. Adult male Wistar rats weighing 250-300 g were used. STZ (icv) was injected during days 1 and 3 (3 mg/kg in divided), and nanocurcumin or curcumin 50 mg/kg/oral gavage was administered daily during days 4-14. Morris water maze training was performed on days 15-17, and the retention memory test was achieved on the 18th day. Following memory assessment, the rats were sacrificed and the hippocampi were used to assess caspase-3 cleavage, Akt, and CaMKII-α signaling. The findings revealed that nanocurcumin ingestion (but not natural curcumin) in the dose of 50 mg/kg was capable to prevent the impairment of water maze learning and memory induced by central STZ. Molecular assessments indicated that STZ treatment increased the caspase-3 cleavage in the hippocampus while deactivating Akt and CaMKII-α. Nanocurcumin reduced caspase-3 cleavage to a non-significant level compared to control group and restored Akt and CaMKII-α within the hippocampus while natural curcumin exerted no significant effect. These findings might suggest that nanocurcumin can restore memory deficit, hippocampal apoptosis as well as Akt and CaMKII-α signaling disruption associated with brain insulin resistance.
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Affiliation(s)
- Maryam Moosavi
- Nanomedicine and Nanobiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Roksana Soukhaklari
- Shiraz Neuroscience Research Centre, Shiraz University of Medical sciences, Shiraz, Iran; Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Saeid Bagheri-Mohammadi
- Department of Paramedicine, Amol School of Paramedical Sciences, Mazandaran University of Medical Sciences, Sari, Iran; Immunogenetics Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Bita Firouzan
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Pegah Javadpour
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Ghasemi
- Department of Physiology and Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Lai AY, Almanza DLV, Ribeiro JA, Hill ME, Mandrozos M, Koletar MM, Stefanovic B, McLaurin J. Obesity Facilitates Sex-Specific Improvement In Cognition And Neuronal Function In A Rat Model Of Alzheimer's Disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.11.575200. [PMID: 38328066 PMCID: PMC10849478 DOI: 10.1101/2024.01.11.575200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Obesity reduces or increases the risk of developing Alzheimer's disease (AD) depending on whether it is assessed in mid-life or late-life. There is currently no consensus on the relationship between obesity and AD or the mechanism or their interaction. Here, we aim to differentiate the cause-and-effect relationship between obesity and AD in a controlled rat model of AD. We induced obesity in 9-month-old TgF344-AD rats, that is pathology-load wise similar to early symptomatic phase of human AD. To more accurately model human obesity, we fed both TgF344-AD and non-transgenic littermates a varied high-carbohydrate-high-fat diet consisting of human food for 3 months. Obesity increased overall glucose metabolism and slowed cognitive decline in TgF344-AD rats, specifically executive function, without affecting non-transgenic rats. Pathological analyses of prefrontal cortex and hippocampus showed that obesity in TgF344-AD rats produced varied effects, with increased density of myelin and oligodendrocytes, lowered density and activation of microglia that we propose contributes to the cognitive improvement. However, obesity also decreased neuronal density, and promoted deposition of amyloid-beta plaques and tau inclusions. After 6 months on the high-carbohydrate-high-fat diet, detrimental effects on density of neurons, amyloid-beta plaques, and tau inclusions persisted while the beneficial effects on myelin, microglia, and cognitive functions remained albeit with a lower effect size. By examining the effect of sex, we found that both beneficial and detrimental effects of obesity were stronger in female TgF344-AD rats indicating that obesity during early symptomatic phase of AD is protective in females.
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Ostovan VR, Baberi N, Farokhi MR, Moezi L, Pirsalami F, Soukhaklari R, Moosavi M. Cholinergic deficit induced memory retrieval impairment and hippocampal CaMKII-alpha deregulation is counteracted by sub-chronic agmatine treatment in mice. Neurol Res 2023; 45:1091-1099. [PMID: 37733020 DOI: 10.1080/01616412.2023.2257417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 07/02/2023] [Indexed: 09/22/2023]
Abstract
Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disease characterized by brain cholinergic dysfunction. Evidence suggests the impairment of memory retrieval phase in AD. It has been shown that CaMKII-α expressing neurons are selectively reduced in the hippocampus in AD brains. The present study aimed to investigate the effect of scopolamine on the memory retrieval phase and the hippocampal CaMKII-α signaling. In addition, the effect of sub-chronic administration of agmatine against scopolamine induced memory and possible hippocampal CaMKII-α deregulation was investigated in mice. Adult male NMRI mice were administered with agmatine at the doses of 5, 10, 20, 30 and 40 mg/kg/i.p. or saline for 11 days. Acquisition and retrieval tests of passive avoidance task were performed on days 10 and 11, respectively (30 Min following agmatine treatment). Scopolamine (1 mg/kg/i.p.) was administered once, 30 Min before retrieval test. Upon completion of the behavioral tasks, the hippocampi were isolated for western blot analysis to detect the phosphorylated and total levels of CaMKII-α and beta actin proteins. The results showed that scopolamine induced memory retrieval deficit and decreased the phosphorylated level of hippocampal CaMKII-α. Sub-chronic agmatine treatment at the dose of 40 mg/kg prevented scopolamine induced memory retrieval deficit and restored the level of hippocampal phosphorylated CaMKII-α. This study suggests that hippocampal CaMKII-α might play a role in scopolamine induced amnesia and sub-chronic agmatine prevents the impairing effect of scopolamine on the retrieval phase of memory and the phosphorylation of hippocampal CaMKII-α protein.
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Affiliation(s)
- Vahid Reza Ostovan
- Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Neurology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Nahid Baberi
- Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Neurology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Majid Reza Farokhi
- Shiraz Neuroscience Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Leila Moezi
- Department of Pharmacology, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fatema Pirsalami
- Department of Pharmacology, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Maryam Moosavi
- Nanomedicine and Nanobiology Research Center, Mohammad Rasoolullah (PBUH) Research Tower, Shiraz University of Medical Sciences, Shiraz, Iran
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Izadi S, Rezaei A, Esmaili Z, Soukhaklari R, Moosavi M. Agmatine prevents the memory impairment and the dysfunction of hippocampal GSK-3β and ERK signaling induced by aluminum nanoparticle in mice. Behav Pharmacol 2023:00008877-990000000-00046. [PMID: 37401404 DOI: 10.1097/fbp.0000000000000735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
The growing usage of aluminum nanoparticles (Al-NP) and their exposure may influence body function. Considering the proposed relationship between Al and the pathogenesis of Alzheimer's disease and the concern about the effect of this nanoparticle on brain health and cognitive function, the use of neuroprotective agents might be helpful. According to the reported neuroprotective effects of agmatine, in the present study, the possible protective effect of agmatine was assessed in mice model of Al-NP-induced memory impairment. In addition, due to the roles of hippocampal Glycogen synthase kinase-3 beta (GSK-3β) and ERK signaling in memory and its disorders, these pathways were also investigated. Al-NP (10 mg/kg/p.o.) with/without agmatine (5 or 10 mg/kg/i.p.) was administered to adult male NMRI mice for 5 days. Novel object recognition (NOR) test session was used to assess cognitive function. Following the behavioral assessments, the hippocampi were used to determine the phosphorylated and total levels of GSK-3β and ERK as well as GAPDH using western blot analysis. The results showed that Al-NP impaired NOR memory in mice while agmatine 10 mg/kg prevented the memory deficit induced by Al-NP. Furthermore, Al-NP activated GSK-3β as well as ERK signals within the hippocampus while agmatine prevented the effects of Al-NP on GSK-3β and ERK signals within the hippocampus. Besides supporting the neuroprotective effects of agmatine, these findings suggest the possibility of the connection of hippocampal GSK-3β and ERK signaling in the neuroprotective effect of this polyamine against Al-NP.
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Affiliation(s)
- Sadegh Izadi
- Clinical Neurology Research Center and Department of Neurology, Shiraz University of Medical Sciences
| | - Amin Rezaei
- Clinical Neurology Research Center and Department of Neurology, Shiraz University of Medical Sciences
| | - Zahra Esmaili
- Nanomedicine and Nanobiology Research Center, Shiraz University of Medical Sciences
| | - Roksana Soukhaklari
- Shiraz Neuroscience Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Maryam Moosavi
- Nanomedicine and Nanobiology Research Center, Shiraz University of Medical Sciences
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Farokhi MR, Taherifard E, SoukhakLari R, Moezi L, Pirsalami F, Savardashtaki A, Moosavi M. The memory modulatory effect of agmatine in passive avoidance task coincides with alterations of hippocampal CaMKII-α and ERK signaling in mice. Eur J Pharmacol 2022; 923:174928. [PMID: 35398030 DOI: 10.1016/j.ejphar.2022.174928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 03/15/2022] [Accepted: 03/25/2022] [Indexed: 11/03/2022]
Abstract
Agmatine is a polyamine suggested to act as a supposed neurotransmitter in the brain. Evidence has indicated that acute agmatine administration might modulate memory. The present study aimed to investigate the effect of repeated agmatine treatment on passive avoidance memory, hippocampal calcium-calmodulin-dependent protein kinase II-alpha (CaMKII-α), and Extracellular Signal-Regulated Kinase (ERK) signaling pathways in naive mice. Adult male NMRI mice were treated with agmatine (10, 20, 30, 40, and 80 mg/kg/ip) or saline for 11 days. Acquisition and retention tests of passive avoidance memory were performed on days 10 and 11, respectively. Following the memory retention test, the hippocampi were assessed for the levels of CaMKII-α and ERK using the western blotting technique. The results revealed the dose-dependent effect of agmatine on the passive avoidance memory. Accordingly, the memory was impaired in lower doses, but was improved in higher ones. Agmatine in none of the doses affected the nociception of the mice in tail-flick test. Furthermore, agmatine increased the phosphorylation of CaMKII-α and ERK in the hippocampus at memory enhancing doses, while ERK phosphorylation decreased following the impairing doses of agmatine. Thus, the dose-dependent effect of agmatine on memory might be related to its modulatory effect on CaMKII-α and ERK signal transduction, eventually regulating the memory process.
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Affiliation(s)
- Majid Reza Farokhi
- Shiraz Neuroscience Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Erfan Taherifard
- Shiraz Neuroscience Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Students Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Roksana SoukhakLari
- Shiraz Neuroscience Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Students Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Leila Moezi
- Department of Pharmacology, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran; Nanomedicine and Nanobiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fatema Pirsalami
- Department of Pharmacology, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir Savardashtaki
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Maryam Moosavi
- Nanomedicine and Nanobiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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Mehrbeheshti N, Esmaili Z, Ahmadi M, Moosavi M. A dose response effect of oral aluminum nanoparticle on novel object recognition memory, hippocampal caspase-3 and MAPKs signaling in mice. Behav Brain Res 2022; 417:113615. [PMID: 34606775 DOI: 10.1016/j.bbr.2021.113615] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 12/30/2022]
Abstract
The increasing use of aluminum nanoparticles (nano-Al) leads to increased human exposure and might affect human health. Considering the suggested connection between aluminum exposure and Alzheimer's disease (AD) pathogenesis, there is a concern about the effect of nano-Al on cognitive function and brain health. This study was aimed to assess the effect of a 5-day oral gavage of aluminum oxide nanoparticle (nano-Al) on memory and the phosphorylation levels of hippocampal p38, JNK (c-Jun N-terminal kinase), ERK (extracellular signal-regulated kinase) as well as cleaved caspase-3 in mice. Adult male NMRI mice were treated with nano-Al in doses 5 and 10 mg/kg/oral gavage for 5 days. The test session of novel object recognition (NOR) task was performed on day 5. Following the NOR test, the hippocampi were isolated for western blot analysis to determine the total and phosphorylated levels of p38, JNK, ERK as well as cleaved caspase-3 proteins. The results showed that nano-Al oral gavage in doses of 5 and 10 mg/kg impairs NOR memory in mice. Moreover, the memory impairing effect of nano-Al coincided with a dose dependent increase in phosphorylated p38 and cleaved caspase-3 in the hippocampus. It also increased the ratio of phosphorylated to total content of ERK in the hippocampus while JNK signaling was not affected by nano-Al. This study showed that nano-Al in doses as low as 5 and 10 mg/ kg ingested for 5 days impairs NOR memory and activates p38, ERK and cleaved caspase-3 in the hippocampus.
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Affiliation(s)
- Nahid Mehrbeheshti
- Shiraz Neuroscience Research Centre, Shiraz University of Medical sciences, Shiraz, Iran
| | - Zahra Esmaili
- Nanobiology and Nanomedicine Research Centre, Shiraz University of Medical sciences, Shiraz, Iran
| | - Mojdeh Ahmadi
- Nanobiology and Nanomedicine Research Centre, Shiraz University of Medical sciences, Shiraz, Iran
| | - Maryam Moosavi
- Nanobiology and Nanomedicine Research Centre, Shiraz University of Medical sciences, Shiraz, Iran.
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Wachal Z, Szilágyi A, Takács B, Szabó AM, Priksz D, Bombicz M, Szilvássy J, Juhász B, Szilvássy Z, Varga B. Improved Survival and Retinal Function of Aging ZDF Rats in Long-Term, Uncontrolled Diabetes by BGP-15 Treatment. Front Pharmacol 2021; 12:650207. [PMID: 33935754 PMCID: PMC8085539 DOI: 10.3389/fphar.2021.650207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/02/2021] [Indexed: 11/13/2022] Open
Abstract
Retinal complications of diabetes often lead to deterioration or even loss of vision. This hastens discovery of pharmacological agents able to counterbalance diabetic retinopathy. BGP-15, an emerging small molecule agent, was formerly proven by our workgroup to be retinoprotective on nonobese diabetic animals, Goto-Kakizaki rats. In the present study, we aimed to examine its long-term tolerability or incidental side effects on obese-prone Zucker diabetic fatty (ZDF) rats to further increase the rationale for a future human translation. To make terminal visual status comparable with our other investigations, we also carried out electroretinography (ERG) at the end of the experiment. Our study was started on 16-week-old ZDF rats and lasted for 52 weeks, while BGP was administered daily by gavage. During the 12 months of treatment, 100% of BGP-treated animals survived compared to the non-treated ZDF group, where 60% of the animals died, which was a statistically significant difference. Based on ERG results, BGP-15 was able to counterbalance visual deterioration of ZDF rats caused by long-term diabetes. Some moderate but significant changes were seen in OGTT results and some relationship to oxidative stress by the western blot method: BGP-15 was able to increase expression of HSP70 and decrease that of NFkB in eyes of rats. These were in concert with our previous observations of SIRT1 increment and MMP9 decrement in diabetic eyes by BGP. In summary, not only is BGP-15 not harmful in the long run but it is even able to reduce the related mortality and the serious consequences of diabetes. BGP-15 is an excellent candidate for future drug development against diabetic retinopathy.
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Affiliation(s)
- Zita Wachal
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Anna Szilágyi
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Barbara Takács
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Adrienn Mónika Szabó
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Dániel Priksz
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Mariann Bombicz
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Judit Szilvássy
- Department of Oto-Rhino-Laryngology and Head and Neck Surgery, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Béla Juhász
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Zoltán Szilvássy
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Balázs Varga
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
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Cerebrovascular damage after midlife transient hypertension in non-transgenic and Alzheimer's disease rats. Brain Res 2021; 1758:147369. [PMID: 33582120 DOI: 10.1016/j.brainres.2021.147369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/03/2021] [Accepted: 02/07/2021] [Indexed: 12/20/2022]
Abstract
Hypertension, including transient events, is a major risk factor for developing late-onset dementia and Alzheimer's disease (AD). Anti-hypertensive drugs facilitate restoration of normotension without amelioration of increased dementia risk suggesting that transient hypertensive insults cause irreversible damage. This study characterized the contribution of transient hypertension to sustained brain damage as a function of normal aging and AD. To model transient hypertension, we treated F344TgAD and non-transgenic littermate rats with L-NG-Nitroarginine methyl ester (L-NAME) for one month, ceased treatment and allowed for a month of normotensive recovery. We then examined the changes in the structure and function of the cerebrovasculature, integrity of white matter, and progression of AD pathology. As independent factors, both transient hypertension and AD compromised structural and functional integrity across the vascular bed, while combined effects of hypertension and AD yielded the largest deficits. Combined effects of transient hypertension and AD genotype resulted in loss of cortical myelin particularly in the cingulate cortex which is crucial for cognitive function. Increased cerebral amyloid angiopathy, a prominent pathology of AD, was detected after transient hypertension as were up- and down-regulation of proteins associated with cerebrovascular remodeling - osteopontin, ROCK1 and ROCK2, in F344TgAD rats even 30 days after restoration of normotension. In conclusion, transient hypertension caused permanent cerebrovasculature and brain parenchymal damage in both normal aging and AD. Our results corroborate human studies that have found close correlation between transient hypertension in midlife and white matter lesions later in life outlining vascular pathologies as pathological links to increased risk of dementia.
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Sanjari Moghaddam H, Ghazi Sherbaf F, Aarabi MH. Brain microstructural abnormalities in type 2 diabetes mellitus: A systematic review of diffusion tensor imaging studies. Front Neuroendocrinol 2019; 55:100782. [PMID: 31401292 DOI: 10.1016/j.yfrne.2019.100782] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 07/27/2019] [Accepted: 08/07/2019] [Indexed: 12/13/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is associated with deficits in the structure and function of the brain. Diffusion tensor imaging (DTI) is a highly sensitive method for characterizing cerebral tissue microstructure. Using PRISMA guidelines, we identified 29 studies which have demonstrated widespread brain microstructural impairment and topological network disorganization in patients with T2DM. Most consistently reported structures with microstructural abnormalities were frontal, temporal, and parietal lobes in the lobar cluster; corpus callosum, cingulum, uncinate fasciculus, corona radiata, and internal and external capsules in the white matter cluster; thalamus in the subcortical cluster; and cerebellum. Microstructural abnormalities were correlated with pathological derangements in the endocrine profile as well as deficits in cognitive performance in the domains of memory, information-processing speed, executive function, and attention. Altogether, the findings suggest that the detrimental effects of T2DM on cognitive functions might be due to microstructural disruptions in the central neural structures.
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Affiliation(s)
| | - Farzaneh Ghazi Sherbaf
- Neuroradiology Division, Tehran University of Medical Sciences, School of Medicine, Tehran, Iran
| | - Mohammad Hadi Aarabi
- Neuroradiology Division, Tehran University of Medical Sciences, School of Medicine, Tehran, Iran.
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