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Clain J, Couret D, Bringart M, Lecadieu A, Meilhac O, Lefebvre d'Hellencourt C, Diotel N. Metabolic disorders exacerbate the formation of glial scar after stroke. Eur J Neurosci 2024; 59:3009-3029. [PMID: 38576159 DOI: 10.1111/ejn.16325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/21/2024] [Accepted: 03/05/2024] [Indexed: 04/06/2024]
Abstract
Metabolic disorders are risk factors for stroke exacerbating subsequent complications. Rapidly after brain injury, a glial scar forms, preventing excessive inflammation and limiting axonal regeneration. Despite the growing interest in wound healing following brain injury, the formation of a glial scar in the context of metabolic disorders is poorly documented. In this study, we used db/db mice to investigate the impact of metabolic perturbations on brain repair mechanisms, with a focus on glial scarring. First, we confirmed the development of obesity, poor glucose regulation, hyperglycaemia and liver steatosis in these mice. Then, we observed that 3 days after a 30-min middle cerebral artery occlusion (MCAO), db/db mice had larger infarct area compared with their control counterparts. We next investigated reactive gliosis and glial scar formation in db/+ and db/db mice. We demonstrated that astrogliosis and microgliosis were exacerbated 3 days after stroke in db/db mice. Furthermore, we also showed that the synthesis of extracellular matrix (ECM) proteins (i.e., chondroitin sulphate proteoglycan, collagen IV and tenascin C) was increased in db/db mice. Consequently, we demonstrated for the first time that metabolic disorders impair reactive gliosis post-stroke and increase ECM deposition. Given that the damage size is known to influence glial scar, this study now raises the question of the direct impact of hyperglycaemia/obesity on reactive gliosis and glia scar. It paves the way to promote the development of new therapies targeting glial scar formation to improve functional recovery after stroke in the context of metabolic disorders.
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Affiliation(s)
- Julien Clain
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
| | - David Couret
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
- CHU de La Réunion, Saint-Denis, France
| | - Matthieu Bringart
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
| | - Arnaud Lecadieu
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
- CHU de La Réunion, Saint-Denis, France
| | - Olivier Meilhac
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
- CHU de La Réunion, Saint-Denis, France
| | - Christian Lefebvre d'Hellencourt
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
| | - Nicolas Diotel
- Université de la Réunion, INSERM, UMR 1188 Diabète Athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint-Pierre, France
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Zhang T, Wu J, Yao X, Zhang Y, Wang Y, Han Y, Wu Y, Xu Z, Lan J, Han S, Zou H, Sun Q, Wang D, Zhang J, Wang G. The Aldose Reductase Inhibitor Epalrestat Maintains Blood-Brain Barrier Integrity by Enhancing Endothelial Cell Function during Cerebral Ischemia. Mol Neurobiol 2023; 60:3741-3757. [PMID: 36940077 DOI: 10.1007/s12035-023-03304-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023]
Abstract
Excessive activation of aldose reductase (AR) in the brain is a risk factor for aggravating cerebral ischemia injury. Epalrestat is the only AR inhibitor with proven safety and efficacy, which is used in the clinical treatment of diabetic neuropathy. However, the molecular mechanisms underlying the neuroprotection of epalrestat remain unknown in the ischemic brain. Recent studies have found that blood-brain barrier (BBB) damage was mainly caused by increased apoptosis and autophagy of brain microvascular endothelial cells (BMVECs) and decreased expression of tight junction proteins. Thus, we hypothesized that the protective effect of epalrestat is mainly related to regulating the survival of BMVECs and tight junction protein levels after cerebral ischemia. To test this hypothesis, a mouse model of cerebral ischemia was established by permanent middle cerebral artery ligation (pMCAL), and the mice were treated with epalrestat or saline as a control. Epalrestat reduced the ischemic volume, enhanced BBB function, and improved the neurobehavior after cerebral ischemia. In vitro studies revealed that epalrestat increased the expression of tight junction proteins, and reduced the levels of cleaved-caspase3 and LC3 proteins in mouse BMVECs (bEnd.3 cells) exposed to oxygen-glucose deprivation (OGD). In addition, bicalutamide (an AKT inhibitor) and rapamycin (an mTOR inhibitor) increased the epalrestat-induced reduction in apoptosis and autophagy related protein levels in bEnd.3 cells with OGD treatment. Our findings suggest that epalrestat improves BBB function, which may be accomplished by reducing AR activation, promoting tight junction proteins expression, and upregulating AKT/mTOR signaling pathway to inhibit apoptosis and autophagy in BMVECs.
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Affiliation(s)
- Tongshuai Zhang
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Jinrong Wu
- Department of Anaesthesiology, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Xinmin Yao
- Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin, 150040, Heilongjiang, China
| | - Yao Zhang
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Yue Wang
- Department of Anesthesiology, Second Affiliated Hospital of Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Yang Han
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Yun Wu
- The Medical Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Zhenyu Xu
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Jing Lan
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Siyu Han
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Haifeng Zou
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Qixu Sun
- Department of Gastroenterology, Penglai People's Hospital, Yantai, 264117, Shandong, China
| | - Dandan Wang
- Wu Lian De Memorial Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China.
| | - Jingyu Zhang
- The Medical Department of Neurology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China.
| | - Guangyou Wang
- Department of Neurobiology, Heilongjiang Provincial Key Laboratory of Neurobiology, Harbin Medical University, Harbin, 150081, Heilongjiang, China.
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The Role of Aldose Reductase in Beta-Amyloid-Induced Microglia Activation. Int J Mol Sci 2022; 23:ijms232315088. [PMID: 36499422 PMCID: PMC9739496 DOI: 10.3390/ijms232315088] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
The occurrence of Alzheimer's disease has been associated with the accumulation of beta-amyloid (β-amyloid) plaques. These plaques activate microglia to secrete inflammatory molecules, which damage neurons in the brain. Thus, understanding the underlying mechanism of microglia activation can provide a therapeutic strategy for alleviating microglia-induced neuroinflammation. The aldose reductase (AR) enzyme catalyzes the reduction of glucose to sorbitol in the polyol pathway. In addition to mediating diabetic complications in hyperglycemic environments, AR also helps regulate inflammation in microglia. However, little is known about the role of AR in β-amyloid-induced inflammation in microglia and subsequent neuronal death. In this study, we confirmed that AR inhibition attenuates increased β-amyloid-induced reactive oxygen species and tumor necrosis factor α secretion by suppressing ERK signaling in BV2 cells. In addition, we are the first to report that AR inhibition reduced the phagocytotic capability and cell migration of BV2 cells in response to β-amyloid. To further investigate the protective role of the AR inhibitor sorbinil in neurons, we co-cultured β-amyloid-induced microglia with stem cell-induced neurons. sorbinil ameliorated neuronal damage in both cells in the co-culture system. In summary, our findings reveal AR regulation of microglia activation as a novel therapeutic target for Alzheimer's disease.
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Anastasiou IA, Eleftheriadou I, Tentolouris A, Koliaki C, Kosta OA, Tentolouris N. CDATA[The Effect of Oxidative Stress and Antioxidant Therapies on Pancreatic β-cell Dysfunction: Results from in Vitro and in Vivo Studies. Curr Med Chem 2021; 28:1328-1346. [PMID: 32452321 DOI: 10.2174/0929867327666200526135642] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 04/07/2020] [Accepted: 04/25/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Oxidative stress is a hallmark of many diseases. A growing body of evidence suggests that hyperglycemia-induced oxidative stress plays an important role in pancreatic β-cells dysfunction and apoptosis, as well as in the development and progression of diabetic complications. Considering the vulnerability of pancreatic β-cells to oxidative damage, the induction of endogenous antioxidant enzymes or exogenous antioxidant administration has been proposed to protect pancreatic β-cells from damage. OBJECTIVES The present review aims to provide evidence of the effect of oxidative stress and antioxidant therapies on pancreatic β-cell function, based on in vitro and in vivo studies. METHODS The MEDLINE and EMBASE databases were searched to retrieve available data. RESULTS Due to poor endogenous antioxidant mechanisms, pancreatic β-cells are extremely sensitive to Reactive Oxygen Species (ROS). Many natural extracts have been tested in vitro in pancreatic β-cell lines in terms of their antioxidant and diabetes mellitus ameliorating effects, and the majority of them have shown a dose-dependent protective role. On the other hand, there is relatively limited evidence regarding the in vitro antioxidant effects of antidiabetic drugs on pancreatic β -cells. Concerning in vivo studies, several natural extracts have shown beneficial effects in the setting of diabetes by decreasing blood glucose and lipid levels, increasing insulin sensitivity, and by up-regulating intrinsic antioxidant enzyme activity. However, there is limited evidence obtained from in vivo studies regarding antidiabetic drugs. CONCLUSION Antioxidants hold promise for developing strategies aimed at the prevention or treatment of diabetes mellitus associated with pancreatic β-cells dysfunction, as supported by in vitro and in vivo studies. However, more in vitro studies are required for drugs.
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Affiliation(s)
- Ioanna A Anastasiou
- Diabetes Center, First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, 17 AgiouThoma St., 11527 Athens, Greece
| | - Ioanna Eleftheriadou
- Diabetes Center, First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, 17 AgiouThoma St., 11527 Athens, Greece
| | - Anastasios Tentolouris
- Diabetes Center, First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, 17 AgiouThoma St., 11527 Athens, Greece
| | - Chrysi Koliaki
- Diabetes Center, First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, 17 AgiouThoma St., 11527 Athens, Greece
| | - Ourania A Kosta
- Diabetes Center, First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, 17 AgiouThoma St., 11527 Athens, Greece
| | - Nikolaos Tentolouris
- Diabetes Center, First Department of Propaedeutic Internal Medicine, Medical School, National and Kapodistrian University of Athens, Laiko General Hospital, 17 AgiouThoma St., 11527 Athens, Greece
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Abstract
Stroke is the fifth leading cause of death and disability in the United States. According to World Heart Federation, every year, 15 million people suffer from stroke worldwide out of which nearly 6 million people die and another 5 million people are disabled. Out of many organs affected after stroke, one of them is eye. Majority of the stroke victims suffer vision loss due to stroke-induced retinal damage. However, stroke-induced retinal damage and microvascular changes have not been given paramount importance in understanding stroke pathophysiology and predicting its occurrence. Retinal imaging can be a very powerful tool to understand and predict stroke. This review will highlight the importance of retinal changes in predicting occurrence of stroke, major retinal changes, the relationship between retinal diseases and stroke and moreover, molecular mechanisms delineating the stroke induced-retinal changes and therapeutics associated with it.
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Affiliation(s)
- Varun Kumar
- Department of Ophthalmology, School of Medicine, Stanford University, Stanford, CA, USA
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Shukla V, Shakya AK, Perez-Pinzon MA, Dave KR. Cerebral ischemic damage in diabetes: an inflammatory perspective. J Neuroinflammation 2017; 14:21. [PMID: 28115020 PMCID: PMC5260103 DOI: 10.1186/s12974-016-0774-5] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/07/2016] [Indexed: 12/16/2022] Open
Abstract
Stroke is one of the leading causes of death worldwide. A strong inflammatory response characterized by activation and release of cytokines, chemokines, adhesion molecules, and proteolytic enzymes contributes to brain damage following stroke. Stroke outcomes are worse among diabetics, resulting in increased mortality and disabilities. Diabetes involves chronic inflammation manifested by reactive oxygen species generation, expression of proinflammatory cytokines, and activation/expression of other inflammatory mediators. It appears that increased proinflammatory processes due to diabetes are further accelerated after cerebral ischemia, leading to increased ischemic damage. Hypoglycemia is an intrinsic side effect owing to glucose-lowering therapy in diabetics, and is known to induce proinflammatory changes as well as exacerbate cerebral damage in experimental stroke. Here, we present a review of available literature on the contribution of neuroinflammation to increased cerebral ischemic damage in diabetics. We also describe the role of hypoglycemia in neuroinflammation and cerebral ischemic damage in diabetics. Understanding the role of neuroinflammatory mechanisms in worsening stroke outcome in diabetics may help limit ischemic brain injury and improve clinical outcomes.
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Affiliation(s)
- Vibha Shukla
- Cerebral Vascular Disease Research Laboratories, University of Miami School of Medicine, Miami, FL, 33136, USA.,Department of Neurology (D4-5), University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA
| | - Akhalesh Kumar Shakya
- Present address: Department of Microbiology and Immunology, and Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, Shreveport, LA, 71130, USA
| | - Miguel A Perez-Pinzon
- Cerebral Vascular Disease Research Laboratories, University of Miami School of Medicine, Miami, FL, 33136, USA.,Department of Neurology (D4-5), University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA.,Neuroscience Program, University of Miami School of Medicine, Miami, FL, 33136, USA
| | - Kunjan R Dave
- Cerebral Vascular Disease Research Laboratories, University of Miami School of Medicine, Miami, FL, 33136, USA. .,Department of Neurology (D4-5), University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA. .,Neuroscience Program, University of Miami School of Medicine, Miami, FL, 33136, USA.
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Hussein AM, Sakr HF, Alenzi FQ. Possible Underlying Mechanisms of the Renoprotective Effect of Remote Limb Ischemic Preconditioning Against Renal Ischemia/Reperfusion Injury: A Role of Osteopontin, Transforming Growth Factor-Beta and Survivin. Nephron Clin Pract 2016; 134:117-129. [PMID: 27486809 DOI: 10.1159/000447953] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/16/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND It has been documented that remote limb ischemic preconditioning (rIPC) protect kidneys against renal ischemia/reperfusion (I/R). We hypothesized that osteopontin (OPN), transforming growth factor beta (TGF-β), apoptotic proteins (survivin and caspase-3) and oxidative stress play role in the renoprotective effects of rIPC. MATERIALS AND METHODS Fifty-four male Sprague-Dawley rats were randomized into 3 equal groups: sham group, I/R group (left renal 45 min ischemia) and rIPC group (as I/R group with 3 cycles of left hind limb ischemia just before renal ischemia). Each group was subdivided into 24, 48 and 72 h groups according to the time of sacrifice. We measured serum creatinine and blood urea nitrogen (BUN) at the baseline and end points. Also, left kidney was harvested at study end points for assessment of the expression of OPN, TGF-β, apoptotic proteins (survivin and caspase-3) and oxidative stress markers (malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD)) in kidney tissues and histopathological examination. RESULTS Serum creatinine and BUN levels and histopathological damage score were significantly lower in rIPC group than I/R group (p < 0.005). Also, compared to I/R group, the levels of MDA and the expression of OPN, TGF-β and caspase-3 in kidney tissues were significantly lower in rIPC group, while the levels of SOD and GSH and the expression of survivin in kidney tissues were significantly higher in rIPC group at all time points (p ≤ 0.05). CONCLUSIONS rIPC exhibited protective effects against renal I/R injury which might be due to inhibition of OPN expression, inflammatory cytokine TGF-β and caspase-3 and activation of anti-apoptotic protein survivin as well as improvement of oxidative stress in kidney tissues.
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Affiliation(s)
- Abdelaziz M Hussein
- Department of Medical Physiology, Mansoura University, Faculty of Medicine, Mansoura, Egypt
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Umemura T, Kawamura T, Hotta N. Pathogenesis and neuroimaging of cerebral large and small vessel disease in type 2 diabetes: A possible link between cerebral and retinal microvascular abnormalities. J Diabetes Investig 2016; 8:134-148. [PMID: 27239779 PMCID: PMC5334292 DOI: 10.1111/jdi.12545] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 05/23/2016] [Indexed: 01/14/2023] Open
Abstract
Diabetes patients have more than double the risk of ischemic stroke compared with non‐diabetic individuals, and its neuroimaging characteristics have important clinical implications. To understand the pathophysiology of ischemic stroke in diabetes, it is important to focus not only on the stroke subtype, but also on the size and location of the occlusive vessels. Specifically, ischemic stroke in diabetes patients might be attributed to both large and small vessels, and intracranial internal carotid artery disease and small infarcts of the posterior circulation often occur. An additional feature is that asymptomatic lacunar infarctions are often seen in the basal ganglia and brain stem on brain magnetic resonance imaging. In particular, cerebral small vessel disease (SVD), including lacunar infarctions, white matter lesions and cerebral microbleeds, has been shown to be associated not only with stroke incidence, but also with the development and progression of dementia and diabetic microangiopathy. However, the pathogenesis of cerebral SVD is not fully understood. In addition, data on the association between neuroimaging findings of the cerebral SVD and diabetes are limited. Recently, the clinical importance of the link between cerebral SVD and retinal microvascular abnormalities has been a topic of considerable interest. Several clinical studies have shown that retinal microvascular abnormalities are closely related to cerebral SVD, suggesting that retinal microvascular abnormalities might be pathophysiologically linked to ischemic cerebral SVD. We review the literature relating to the pathophysiology and neuroimaging of cerebrovascular disease in diabetes, and discuss the problems based on the concept of cerebral large and small vessel disease.
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Affiliation(s)
| | - Takahiko Kawamura
- Department of Diabetes and Endocrine Internal Medicine, Chubu Rosai Hospital, Nagoya, Japan.,Department of Preventive Medical Center, Chubu Rosai Hospital, Nagoya, Japan
| | - Nigishi Hotta
- Department of Diabetes and Endocrine Internal Medicine, Chubu Rosai Hospital, Nagoya, Japan
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Abstract
Neuropathy is the most common complication of diabetes. As a consequence of longstanding hyperglycemia, a downstream metabolic cascade leads to peripheral nerve injury through an increased flux of the polyol pathway, enhanced advanced glycation end‐products formation, excessive release of cytokines, activation of protein kinase C and exaggerated oxidative stress, as well as other confounding factors. Although these metabolic aberrations are deemed as the main stream for the pathogenesis of diabetic microvascular complications, organ‐specific histological and biochemical characteristics constitute distinct mechanistic processes of neuropathy different from retinopathy or nephropathy. Extremely long axons originating in the small neuronal body are vulnerable on the most distal side as a result of malnutritional axonal support or environmental insults. Sparse vascular supply with impaired autoregulation is likely to cause hypoxic damage in the nerve. Such dual influences exerted by long‐term hyperglycemia are critical for peripheral nerve damage, resulting in distal‐predominant nerve fiber degeneration. More recently, cellular factors derived from the bone marrow also appear to have a strong impact on the development of peripheral nerve pathology. As evident from such complicated processes, inhibition of single metabolic factors might not be sufficient for the treatment of neuropathy, but a combination of several inhibitors might be a promising approach to overcome this serious disorder. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00070.x, 2010)
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Affiliation(s)
| | | | - Kazuhiro Sugimoto
- Laboratory Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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Yan LJ. Pathogenesis of chronic hyperglycemia: from reductive stress to oxidative stress. J Diabetes Res 2014; 2014:137919. [PMID: 25019091 PMCID: PMC4082845 DOI: 10.1155/2014/137919] [Citation(s) in RCA: 226] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/27/2014] [Indexed: 02/08/2023] Open
Abstract
Chronic overnutrition creates chronic hyperglycemia that can gradually induce insulin resistance and insulin secretion impairment. These disorders, if not intervened, will eventually be followed by appearance of frank diabetes. The mechanisms of this chronic pathogenic process are complex but have been suggested to involve production of reactive oxygen species (ROS) and oxidative stress. In this review, I highlight evidence that reductive stress imposed by overflux of NADH through the mitochondrial electron transport chain is the source of oxidative stress, which is based on establishments that more NADH recycling by mitochondrial complex I leads to more electron leakage and thus more ROS production. The elevated levels of both NADH and ROS can inhibit and inactivate glyceraldehyde 3-phosphate dehydrogenase (GAPDH), respectively, resulting in blockage of the glycolytic pathway and accumulation of glycerol 3-phospate and its prior metabolites along the pathway. This accumulation then initiates all those alternative glucose metabolic pathways such as the polyol pathway and the advanced glycation pathways that otherwise are minor and insignificant under euglycemic conditions. Importantly, all these alternative pathways lead to ROS production, thus aggravating cellular oxidative stress. Therefore, reductive stress followed by oxidative stress comprises a major mechanism of hyperglycemia-induced metabolic syndrome.
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Affiliation(s)
- Liang-Jun Yan
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, RES-314E, Fort Worth, TX 76107, USA
- *Liang-Jun Yan:
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Rueda A, Fernández-Velasco M, Benitah JP, Gómez AM. Abnormal Ca2+ spark/STOC coupling in cerebral artery smooth muscle cells of obese type 2 diabetic mice. PLoS One 2013; 8:e53321. [PMID: 23301060 PMCID: PMC3536748 DOI: 10.1371/journal.pone.0053321] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 11/30/2012] [Indexed: 01/19/2023] Open
Abstract
Diabetes is a major risk factor for stroke. However, the molecular mechanisms involved in cerebral artery dysfunction found in the diabetic patients are not completely elucidated. In cerebral artery smooth muscle cells (CASMCs), spontaneous and local increases of intracellular Ca2+ due to the opening of ryanodine receptors (Ca2+ sparks) activate large conductance Ca2+-activated K+ (BK) channels that generate spontaneous transient outward currents (STOCs). STOCs have a key participation in the control of vascular myogenic tone and blood pressure. Our goal was to investigate whether alterations in Ca(2+) spark and STOC activities, measured by confocal microscopy and patch-clamp technique, respectively, occur in isolated CASMCs of an experimental model of type-2 diabetes (db/db mouse). We found that mean Ca(2+) spark amplitude, duration, size and rate-of-rise were significantly smaller in Fluo-3 loaded db/db compared to control CASMCs, with a subsequent decrease in the total amount of Ca(2+) released through Ca(2+) sparks in db/db CASMCs, though Ca(2+) spark frequency remained. Interestingly, the frequency of large-amplitude Ca(2+) sparks was also significantly reduced in db/db cells. In addition, the frequency and amplitude of STOCs were markedly reduced at all voltages tested (from -50 to 0 mV) in db/db CASMCs. The latter correlates with decreased BK channel β1/α subunit ratio found in db/db vascular tissues. Taken together, Ca(2+) spark alterations lead to inappropriate BK channels activation in CASMCs of db/db mice and this condition is aggravated by the decrease in the BK β1 subunit/α subunit ratio which underlies the significant reduction of Ca(2+) spark/STOC coupling in CASMCs of diabetic animals.
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Affiliation(s)
- Angélica Rueda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN, México City, México
- Inserm, U-637; Université de Montpellier 1, Université de Montpellier 2, Montpellier, France
- * E-mail: (AMG); (AR)
| | - María Fernández-Velasco
- Inserm, U-637; Université de Montpellier 1, Université de Montpellier 2, Montpellier, France
- Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | - Jean-Pierre Benitah
- Inserm, U769; Université de Paris-Sud, IFR141, Labex Lermit, Châtenay-Malabry, France
| | - Ana María Gómez
- Inserm, U769; Université de Paris-Sud, IFR141, Labex Lermit, Châtenay-Malabry, France
- * E-mail: (AMG); (AR)
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12
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Lycium barbarum extracts protect the brain from blood-brain barrier disruption and cerebral edema in experimental stroke. PLoS One 2012; 7:e33596. [PMID: 22438957 PMCID: PMC3306421 DOI: 10.1371/journal.pone.0033596] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 02/12/2012] [Indexed: 11/28/2022] Open
Abstract
Background and Purpose Ischemic stroke is a destructive cerebrovascular disease and a leading cause of death. Yet, no ideal neuroprotective agents are available, leaving prevention an attractive alternative. The extracts from the fruits of Lycium barbarum (LBP), a Chinese anti-aging medicine and food supplement, showed neuroprotective function in the retina when given prophylactically. We aim to evaluate the protective effects of LBP pre-treatment in an experimental stroke model. Methods C57BL/6N male mice were first fed with either vehicle (PBS) or LBP (1 or 10 mg/kg) daily for 7 days. Mice were then subjected to 2-hour transient middle cerebral artery occlusion (MCAO) by the intraluminal method followed by 22-hour reperfusion upon filament removal. Mice were evaluated for neurological deficits just before sacrifice. Brains were harvested for infarct size estimation, water content measurement, immunohistochemical analysis, and Western blot experiments. Evans blue (EB) extravasation was determined to assess blood-brain barrier (BBB) disruption after MCAO. Results LBP pre-treatment significantly improved neurological deficits as well as decreased infarct size, hemispheric swelling, and water content. Fewer apoptotic cells were identified in LBP-treated brains by TUNEL assay. Reduced EB extravasation, fewer IgG-leaky vessels, and up-regulation of occludin expression were also observed in LBP-treated brains. Moreover, immunoreactivity for aquaporin-4 and glial fibrillary acidic protein were significantly decreased in LBP-treated brains. Conclusions Seven-day oral LBP pre-treatment effectively improved neurological deficits, decreased infarct size and cerebral edema as well as protected the brain from BBB disruption, aquaporin-4 up-regulation, and glial activation. The present study suggests that LBP may be used as a prophylactic neuroprotectant in patients at high risk for ischemic stroke.
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Tang L, Zhang Y, Jiang Y, Willard L, Ortiz E, Wark L, Medeiros D, Lin D. Dietary wolfberry ameliorates retinal structure abnormalities in db/db mice at the early stage of diabetes. Exp Biol Med (Maywood) 2011; 236:1051-63. [PMID: 21750018 DOI: 10.1258/ebm.2011.010400] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hyperglycemia-linked oxidative stress and/or consequent endoplasmic reticulum (ER) stress are the causative factors of pathogenesis of diabetic retinopathy. Dietary bioactive components which mitigate oxidative stress may serve as potential chemopreventive agents to prevent or slow down the disease progression. Wolfberry is a traditional Asian fruit consumed for years to prevent aging eye diseases in Asian countries. Here we report that dietary wolfberry ameliorated mouse retinal abnormality at the early stage of type 2 diabetes in db/db mice. Male mice at six weeks of age were fed the control diet with or without 1% (kcal) wolfberry for eight weeks. Dietary wolfberry restored the thickness of the whole retina, in particular the inner nuclear layer and photoreceptor layer, and the integrity of the retinal pigment epithelia (RPE), and the ganglion cell number in db/db mice. Western blotting of whole retinal cell lysates revealed that addition of wolfberry lowered expression of ER stress biomarkers binding immunoglobulin protein (BiP), protein kinase RNA-like ER kinase (PERK), activating transcription factor 6 (ATF6) and caspase-12, and restored AMP-activated protein kinase (AMPK), thioredoxin, Mn superoxide dismutase (Mn SOD) and forkhead O transcription factor 3 α (FOXO3α) activities. To determine if our observations were due to the high contents of zeaxanthin and lutein in wolfberry, additional studies using these carotenoids were conducted. Using the human adult diploid RPE cell line ARPE-19, we demonstrated that both zeaxanthin and lutein could mimic the wolfberry preventive effect on activation of AMPK, thioredoxin, Mn SOD, FOXO3α activities, normalize cellular reactive oxygen species and attenuate ER stress in ARPE-19 cells exposed to a high glucose challenge. The zeaxanthin preventive effect was abolished by small interfering RNA knockdown of AMPKα. These results suggested that AMPK activation appeared to play a key role in upregulated expression of thioredoxin and Mn SOD, and mitigation of cellular oxidative stress and/or ER stress by wolfberry and zeaxanthin and/or lutein. Taken together, dietary wolfberry on retinal protection in diabetic mice is, at least partially, due to zeaxanthin and/or lutein.
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Affiliation(s)
- Ling Tang
- Department of Human Nutrition, Kansas State University, Manhattan, KS 66506, USA
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Badaut J, Ashwal S, Obenaus A. Aquaporins in cerebrovascular disease: a target for treatment of brain edema? Cerebrovasc Dis 2011; 31:521-31. [PMID: 21487216 PMCID: PMC3085520 DOI: 10.1159/000324328] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 01/11/2011] [Indexed: 12/11/2022] Open
Abstract
In cerebrovascular disease, edema formation is frequently observed within the first 7 days and is characterized by molecular and cellular changes in the neurovascular unit. The presence of water channels, aquaporins (AQPs), within the neurovascular unit has led to intensive research in understanding the underlying roles of each of the AQPs under normal conditions and in different diseases. In this review, we summarize some of the recent knowledge on AQPs, focusing on AQP4, the most abundant AQP in the central nervous system. Several experimental models illustrate that AQPs have dual, complex regulatory roles in edema formation and resolution. To date, no specific therapeutic agents have been developed to inhibit water flux through these channels. However, experimental results strongly suggest that this is an important area for future investigation. In fact, early inhibition of water channels may have positive effects in the prevention of edema formation. At later time points during the course of disease, AQP is important for the clearance of water from the brain into blood vessels. Thus, AQPs, and in particular AQP4, have important roles in the resolution of edema after brain injury. The function of these water channel proteins makes them an excellent therapeutic target.
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Affiliation(s)
- J Badaut
- Department of Pediatrics, Loma Linda University School of Medicine, Calif., USA.
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Reddy ABM, Tammali R, Mishra R, Srivastava S, Srivastava SK, Ramana KV. Aldose reductase deficiency protects sugar-induced lens opacification in rats. Chem Biol Interact 2011; 191:346-50. [PMID: 21376710 DOI: 10.1016/j.cbi.2011.02.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 02/23/2011] [Accepted: 02/24/2011] [Indexed: 11/26/2022]
Abstract
Aldose reductase (AKR1B1), which catalyzes the reduction of glucose to sorbitol and lipid aldehydes to lipid alcohols, has been shown to be involved in secondary diabetic complications including cataractogenesis. Rats have high levels of AKR1B1 in lenses and readily develop diabetic cataracts, whereas mice have very low levels of AKR1B1 in their lenses and are not susceptible to hyperglycemic cataracts. Studies with transgenic mice that over-express AKR1B1 indicate that it is the key protein for the development of diabetic complications including diabetic cataract. However, no such studies were performed in genetically altered AKR1B1 rats. Hence, we developed siRNA-based AKR1B1 knockdown rats (ARKO) using the AKR1B1-siRNA-pSuper vector construct. Genotyping analysis suggested that more than 90% of AKR1B1 was knocked down in the littermates. Interestingly, all the male animals were born dead and only 3 female rats survived. Furthermore, all 3 female animals were not able to give birth to F1 generation. Hence, we could not establish an AKR1B1 rat knockdown colony. However, we examined the effect of AKR1B1 knockdown on sugar-induced lens opacification in ex vivo. Our results indicate that rat lenses obtained from AKR1B1 knockdown rats were resistant to high glucose-induced lens opacification as compared to wild-type (WT) rat lenses. Biochemical analysis of lens homogenates showed that the AKR1B1 activity and sorbitol levels were significantly lower in sugar-treated AKR1B1 knockdown rat lenses as compared to WT rat lenses treated with 50mM glucose. Our results thus confirmed the significance of AKR1B1 in the mediation of sugar-induced lens opacification and indicate the use of AKR1B1 inhibitors in the prevention of cataractogenesis.
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Affiliation(s)
- Aramati B M Reddy
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, United States
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Tureyen K, Bowen K, Liang J, Dempsey RJ, Vemuganti R. Exacerbated brain damage, edema and inflammation in type-2 diabetic mice subjected to focal ischemia. J Neurochem 2011; 116:499-507. [PMID: 21133923 DOI: 10.1111/j.1471-4159.2010.07127.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One of the limiting factors in stroke therapeutic development is the use of animal models that do not well represent the underlying medical conditions of patients. In humans, diabetes increases the risk of stroke incidence as well as post-stroke mortality. To understand the mechanisms that render diabetics to increased brain damage, we evaluated the effect of transient middle cerebral artery occlusion in adult db/db mice. The db/db mouse is a model of type-2 diabetes with four times higher blood sugar than its normoglycemic genetic control(db/+ mouse). Following transient middle cerebral artery occlusion, the db/db mice showed significantly higher mortality, bigger infarcts, increased cerebral edema, worsened neurological status compared to db/+ mice. The db/db mice also showed significantly higher post-ischemic inflammatory markers (ICAM1(+) capillaries, extravasated macrophages/neutrophils and exacerbated proinflammatory gene expression) compared to db/+ mice. In addition, the post-ischemic neuroprotective heat-shock chaperone gene expression was curtailed in the db/db compared to db/+ mice.
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Affiliation(s)
- Kudret Tureyen
- Department of Neurological Surgery, University of Wisconsin, Madison, WI 53792, USA
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