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Tang C, Border JJ, Zhang H, Gregory A, Bai S, Fang X, Liu Y, Wang S, Hwang SH, Gao W, Morgan GC, Smith J, Bunn D, Cantwell C, Wagner KM, Morisseau C, Yang J, Shin SM, O'Herron P, Bagi Z, Filosa JA, Dong Y, Yu H, Hammock BD, Roman RJ, Fan F. Inhibition of Soluble Epoxide Hydrolase Ameliorates Cerebral Blood Flow Autoregulation and Cognition in Alzheimer's Disease and Diabetes-Related Dementia Rat Models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.30.610540. [PMID: 39257786 PMCID: PMC11383657 DOI: 10.1101/2024.08.30.610540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Alzheimer's Disease and Alzheimer's Disease-related dementias (AD/ADRD) pose major global healthcare challenges, with diabetes mellitus (DM) being a key risk factor. Both AD and DM-related ADRD are characterized by reduced cerebral blood flow, although the exact mechanisms remain unclear. We previously identified compromised cerebral hemodynamics as early signs in TgF344-AD and type 2 DM-ADRD (T2DN) rat models. Genome-wide studies have linked AD/ADRD to SNPs in soluble epoxide hydrolase (sEH). This study explored the effects of sEH inhibition with TPPU on cerebral vascular function and cognition in AD and DM-ADRD models. Chronic TPPU treatment improved cognition in both AD and DM-ADRD rats without affecting body weight. In DM-ADRD rats, TPPU reduced plasma glucose and HbA1C levels. Transcriptomic analysis of primary cerebral vascular smooth muscle cells from AD rats treated with TPPU revealed enhanced pathways related to cell contraction, alongside decreased oxidative stress and inflammation. Both AD and DM-ADRD rats exhibited impaired myogenic responses and autoregulation in the cerebral circulation, which were normalized with chronic sEH inhibition. Additionally, TPPU improved acetylcholine-induced vasodilation in the middle cerebral arteries (MCA) of DM-ADRD rats. Acute TPPU administration unexpectedly caused vasoconstriction in the MCA of DM-ADRD rats at lower doses. In contrast, higher doses or longer durations were required to induce effective vasodilation at physiological perfusion pressure in both control and ADRD rats. Additionally, TPPU decreased reactive oxygen species production in cerebral vessels of AD and DM-ADRD rats. These findings provide novel evidence that chronic sEH inhibition can reverse cerebrovascular dysfunction and cognitive impairments in AD/ADRD, offering a promising avenue for therapeutic development.
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Affiliation(s)
- Chengyun Tang
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Jane J Border
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Huawei Zhang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Andrew Gregory
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Shan Bai
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA
| | - Xing Fang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Yedan Liu
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Shaoxun Wang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Sung Hee Hwang
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Wenjun Gao
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
| | - Gilbert C Morgan
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Jhania Smith
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - David Bunn
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Cameron Cantwell
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Karen M Wagner
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Christophe Morisseau
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Jun Yang
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Seung Min Shin
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI
| | - Philip O'Herron
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Zsolt Bagi
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Jessica A Filosa
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Yanbin Dong
- Georgia Prevention Center, Augusta University, Augusta, GA
| | - Hongwei Yu
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI
| | - Bruce D Hammock
- Entomology and Nematology and UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA
| | - Richard J Roman
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
| | - Fan Fan
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS
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Tang C, Zhang H, Border JJ, Liu Y, Fang X, Jefferson JR, Gregory A, Johnson C, Lee TJ, Bai S, Sharma A, Shin SM, Yu H, Roman RJ, Fan F. Impact of knockout of dual-specificity protein phosphatase 5 on structural and mechanical properties of rat middle cerebral arteries: implications for vascular aging. GeroScience 2024; 46:3135-3147. [PMID: 38200357 PMCID: PMC11009215 DOI: 10.1007/s11357-024-01061-y] [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: 12/07/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
Vascular aging influences hemodynamics, elevating risks for vascular diseases and dementia. We recently demonstrated that knockout (KO) of Dusp5 enhances cerebral and renal hemodynamics and cognitive function. This improvement correlates with elevated pPKC and pERK1/2 levels in the brain and kidneys. Additionally, we observed that Dusp5 KO modulates the passive mechanical properties of cerebral and renal arterioles, associated with increased myogenic tone at low pressure, enhanced distensibility, greater compliance, and reduced stiffness. The present study evaluates the structural and mechanical properties of the middle cerebral artery (MCA) in Dusp5 KO rats. We found that vascular smooth muscle cell layers and the collagen content in the MCA wall are comparable between Dusp5 KO and control rats. The internal elastic lamina in the MCA of Dusp5 KO rats exhibits increased thickness, higher autofluorescence intensity, smaller fenestrae areas, and fewer fenestrations. Despite an enhanced myogenic response and tone of the MCA in Dusp5 KO rats, other passive mechanical properties, such as wall thickness, cross-sectional area, wall-to-lumen ratio, distensibility, incremental elasticity, circumferential wall stress, and elastic modulus, do not significantly differ between strains. These findings suggest that while Dusp5 KO has a limited impact on altering the structural and mechanical properties of MCA, its primary role in ameliorating hemodynamics and cognitive functions is likely attributable to its enzymatic activity on cerebral arterioles. Further research is needed to elucidate the specific enzymatic mechanisms and explore potential clinical applications in the context of vascular aging.
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Affiliation(s)
- Chengyun Tang
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Huawei Zhang
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Jane J Border
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Yedan Liu
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Xing Fang
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Joshua R Jefferson
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Andrew Gregory
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Claire Johnson
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Tae Jin Lee
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Shan Bai
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Ashok Sharma
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Seung Min Shin
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Hongwei Yu
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Richard J Roman
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Fan Fan
- Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, MS, USA.
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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Guzzi PH, Cortese F, Mannino GC, Pedace E, Succurro E, Andreozzi F, Veltri P. Analysis of age-dependent gene-expression in human tissues for studying diabetes comorbidities. Sci Rep 2023; 13:10372. [PMID: 37365269 DOI: 10.1038/s41598-023-37550-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023] Open
Abstract
The study of the relationship between type 2 diabetes mellitus (T2DM) disease and other pathologies (comorbidities), together with patient age variation, poses a challenge for medical research. There is evidence that patients affected by T2DM are more likely to develop comorbidities as they grow older. Variation of gene expression can be correlated to changes in T2DM comorbidities insurgence and progression. Understanding gene expression changes requires the analysis of large heterogeneous data at different scales as well as the integration of different data sources into network medicine models. Hence, we designed a framework to shed light on uncertainties related to age effects and comorbidity by integrating existing data sources with novel algorithms. The framework is based on integrating and analysing existing data sources under the hypothesis that changes in the basal expression of genes may be responsible for the higher prevalence of comorbidities in older patients. Using the proposed framework, we selected genes related to comorbidities from existing databases, and then analysed their expression with age at the tissues level. We found a set of genes that changes significantly in certain specific tissues over time. We also reconstructed the associated protein interaction networks and the related pathways for each tissue. Using this mechanistic framework, we detected interesting pathways related to T2DM whose genes change their expression with age. We also found many pathways related to insulin regulation and brain activities, which can be used to develop specific therapies. To the best of our knowledge, this is the first study that analyses such genes at the tissue level together with age variations.
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Affiliation(s)
- Pietro Hiram Guzzi
- Department of Surgical and Medical Sciences, Magna Graecia University, 88100, Catanzaro, Italy.
| | - Francesca Cortese
- Department of Surgical and Medical Sciences, Magna Graecia University, 88100, Catanzaro, Italy
| | - Gaia Chiara Mannino
- Department of Surgical and Medical Sciences, Magna Graecia University, 88100, Catanzaro, Italy
| | - Elisabetta Pedace
- Internal Medicine Unit, ASP Catanzaro, Soverato Hospital, Soverato, Italy
| | - Elena Succurro
- Department of Surgical and Medical Sciences, Magna Graecia University, 88100, Catanzaro, Italy
- Internal Medicine Unit, R. Dulbecco Hospital, 88100, Catanzaro, Italy
| | - Francesco Andreozzi
- Department of Surgical and Medical Sciences, Magna Graecia University, 88100, Catanzaro, Italy
- Internal Medicine Unit, R. Dulbecco Hospital, 88100, Catanzaro, Italy
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Fang X, Tang C, Zhang H, Border JJ, Liu Y, Shin SM, Yu H, Roman RJ, Fan F. Longitudinal characterization of cerebral hemodynamics in the TgF344-AD rat model of Alzheimer's disease. GeroScience 2023; 45:1471-1490. [PMID: 36933144 PMCID: PMC10400494 DOI: 10.1007/s11357-023-00773-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 03/12/2023] [Indexed: 03/19/2023] Open
Abstract
Alzheimer's disease (AD) is a global healthcare crisis. The TgF344-AD rat is an AD model exhibiting age-dependent AD pathological hallmarks. We confirmed that AD rats developed cognitive deficits at 6 months without alteration of any other major biophysical parameters. We longitudinally characterized cerebral hemodynamics in AD rats at 3, 4, 6, and 14 months. The myogenic responses of the cerebral arteries and arterioles were impaired at 4 months of age in the AD rats. Consistent with the ex vivo results, the AD rat exhibited poor autoregulation of surface and deep cortical cerebral blood flow 2 months preceding cognitive decline. The dysfunction of cerebral hemodynamics in AD is exacerbated with age associated with reduced cerebral perfusion. Further, abolished cell contractility contributes to cerebral hemodynamics imbalance in AD. This may be attributed to enhanced ROS production, reduced mitochondrial respiration and ATP production, and disrupted actin cytoskeleton in cerebral vascular contractile cells.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Chengyun Tang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Seung Min Shin
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI, 53226, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
- Department of Physiology, Medical College of Georgia, Augusta University, 1462 Laney Walker Blvd, Augusta, GA, 30912, USA.
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Zhang H, Border JJ, Fang X, Liu Y, Tang C, Gao W, Wang S, Shin SM, Guo Y, Zhang C, Gonzalez-Fernandez E, Yu H, Sun P, Roman RJ, Fan F. Enhanced Cerebral Hemodynamics and Cognitive Function Via Knockout of Dual-Specificity Protein Phosphatase 5. JOURNAL OF PHARMACY AND PHARMACOLOGY RESEARCH 2023; 7:49-61. [PMID: 37588944 PMCID: PMC10430881 DOI: 10.26502/fjppr.070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Alzheimer's Disease (AD) and Alzheimer's Disease-Related Dementias (ADRD) are neurodegenerative disorders. Recent studies suggest that cerebral hypoperfusion is an early symptom of AD/ADRD. Dual-specificity protein phosphatase 5 (DUSP5) has been implicated in several pathological conditions, including pulmonary hypertension and cancer, but its role in AD/ADRD remains unclear. The present study builds on our previous findings, demonstrating that inhibition of ERK and PKC leads to a dose-dependent dilation of the middle cerebral artery and penetrating arteriole, with a more pronounced effect in Dusp5 KO rats. Both ERK and PKC inhibitors resulted in a significant reduction of myogenic tone in vessels from Dusp5 KO rats. Dusp5 KO rats exhibited stronger autoregulation of the surface but not deep cortical cerebral blood flow. Inhibition of ERK and PKC significantly enhanced the contractile capacity of vascular smooth muscle cells from both strains. Finally, a significant improvement in learning and memory was observed in Dusp5 KO rats 24 hours after initial training. Our results suggest that altered vascular reactivity in Dusp5 KO rats may involve distinct mechanisms for different vascular beds, and DUSP5 deletion could be a potential therapeutic target for AD/ADRD. Further investigations are necessary to determine the effects of DUSP5 inhibition on capillary stalling, blood-brain barrier permeability, and neurodegeneration in aging and disease models.
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Affiliation(s)
- Huawei Zhang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Neurosurgery, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jane J Border
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Xing Fang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Yedan Liu
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Chengyun Tang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wenjun Gao
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Shaoxun Wang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Seung Min Shin
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ya Guo
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Chao Zhang
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | | | - Hongwei Yu
- Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Peng Sun
- Neurosurgery, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Richard J Roman
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Fan Fan
- Pharmacology &Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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Fang X, Zhang J, Roman RJ, Fan F. From 1901 to 2022, how far are we from truly understanding the pathogenesis of age-related dementia? GeroScience 2022; 44:1879-1883. [PMID: 35585301 PMCID: PMC9213583 DOI: 10.1007/s11357-022-00591-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/29/2022] [Indexed: 11/04/2022] Open
Abstract
From the first described AD case in 1901 to the current year 2022, understanding the pathogenesis of Alzheimer's disease (AD) and dementia has undergone a long and tortuous journey. Many mechanisms of AD etiology have been proposed and studied. However, current medications and FDA-approved treatments cannot cure AD and AD-related dementias (AD/ADRD). Recently, brain hypoperfusion associated with neurovascular dysfunction was recognized as one of the causal factors in the development of AD dementia. Arteriosclerotic changes were observed in the first AD case. A recent study reported that the functional hyperemic response to whisker stimulation was reduced in 9-12 months old atherosclerotic mice. Interestingly, they found that evoked hemodynamic responses were not altered in age-matched AD mice or AD mice with superimposed atherosclerosis using 2D-optical imaging spectroscopy in chronic studies. However, functional hyperemia was impaired in AD mice using the same approach in an acute study. It is essential to scrutinize the available data critically since different genetic backgrounds, ages, sexes of studied animal models, and different approaches used for the same function even structural examination may provide opposite information. We certainly are closer to truly understanding the pathogenesis of dementia. We expect positive results from using aducanumab (Aduhelm®) as the first FDA-approved anti-amyloid monoclonal antibody as a treatment for AD/ADRD. We hope to identify and develop new drugs targeting other potential contributing mechanisms such as the cerebral vascular pathways.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Jin Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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Li T, Xu G, Yi J, Huang Y. Intraoperative Hypothermia Induces Vascular Dysfunction in the CA1 Region of Rat Hippocampus. Brain Sci 2022; 12:brainsci12060692. [PMID: 35741578 PMCID: PMC9221322 DOI: 10.3390/brainsci12060692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/19/2022] [Accepted: 05/25/2022] [Indexed: 02/05/2023] Open
Abstract
Intraoperative hypothermia is very common and leads to memory decline. The hippocampus is responsible for memory formation. As a functional core area, the cornu ammonis 1 (CA1) region of the hippocampus contains abundant blood vessels and is susceptible to ischemia. The aim of the study was to explore vascular function and neuronal state in the CA1 region of rats undergoing intraoperative hypothermia. The neuronal morphological change and activity-regulated cytoskeleton-associated protein (Arc) expression were evaluated by haematoxylin-eosin staining and immunofluorescence respectively. Histology and immunohistochemistry were used to assess vascular function. Results showed that intraoperative hypothermia inhibited the expression of vascular endothelial growth factor and endothelial nitric oxide synthase, and caused reactive oxygen species accumulation. Additionally, the phenotype of vascular smooth muscle cells was transformed from contractile to synthetic, showing a decrease in smooth muscle myosin heavy chain and an increase in osteopontin. Ultimately, vascular dysfunction caused neuronal pyknosis in the CA1 region and reduced memory-related Arc expression. In conclusion, neuronal disorder in the CA1 region was caused by intraoperative hypothermia-related vascular dysfunction. This study could provide a novel understanding of the effect of intraoperative hypothermia in the hippocampus, which might identify a new research target and treatment strategy.
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Fang X, Crumpler RF, Thomas KN, Mazique JN, Roman RJ, Fan F. Contribution of cerebral microvascular mechanisms to age-related cognitive impairment and dementia. Physiol Int 2022; 109:10.1556/2060.2022.00020. [PMID: 35238800 PMCID: PMC10710737 DOI: 10.1556/2060.2022.00020] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/03/2022] [Indexed: 11/19/2022]
Abstract
Cognitive impairment and dementia are significant health burdens worldwide. Aging, hypertension, and diabetes are the primary risk factors for Alzheimer's disease and Alzheimer's disease and related dementias (AD/ADRD). There are no effective treatments for AD/ADRD to date. An emerging body of evidence indicates that cerebral vascular dysfunction and hypoperfusion precedes the development of other AD pathological phenotypes and cognitive impairment. However, vascular contribution to dementia is not currently well understood. This commentary highlights the emerging concepts and mechanisms underlying the microvascular contribution to AD/ADRD, including hypotheses targeting the anterograde and retrograde cerebral vascular pathways, as well as the cerebral capillaries and the venous system. We also briefly discuss vascular endothelial dysfunction, oxidative stress, inflammation, and cellular senescence that may contribute to impaired cerebral blood flow autoregulation, neurovascular uncoupling, and dysfunction of cerebral capillaries and the venous system.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Reece F. Crumpler
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Kirby N. Thomas
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Jena’ N. Mazique
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
- Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS 39216, USA
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Zhang H, Roman RJ, Fan F. Hippocampus is more susceptible to hypoxic injury: has the Rosetta Stone of regional variation in neurovascular coupling been deciphered? GeroScience 2022; 44:127-130. [PMID: 34453273 PMCID: PMC8810993 DOI: 10.1007/s11357-021-00449-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 10/20/2022] Open
Abstract
Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) are associated with cerebral hypoperfusion or reductions in baseline cerebral blood flow (CBF). The neurovascular coupling (NVC) response or functional hyperemia regulates brain perfusion via a retrograde (capillary-to-arteriole) pathway by increasing regional CBF in response to local neuron activation. The hippocampus plays a significant role in spatial and non-spatial memory. Functional MRI (fMRI) has not established a solid positive correlation between hippocampal blood oxygen level-dependent (BOLD) signal and local neuronal activity. The inconsistency of NVC in the hippocampus compared to the neocortex is possibly due to anatomical and methodological difficulties to accurately detect hippocampal blood flow. A recent study reported that NVC and oxygenation are reduced in the hippocampus compared to the cortex using a novel invasive surgical approach by creating a cranial window with and without removing the neocortex. Results from these studies suggest that the hippocampus is more susceptible to hypoxic injury in pathological conditions when NVC is impaired, such as AD/ADRD, stroke, and traumatic brain injury (TBI). The Rosetta Stone of regional variation in the NVC and its significance in AD/ADRD has not been fully deciphered based on these results without addressing remaining concerns; however, we are one step closer, indeed.
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Affiliation(s)
- Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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Wang S, Jiao F, Border JJ, Fang X, Crumpler RF, Liu Y, Zhang H, Jefferson J, Guo Y, Elliott PS, Thomas KN, Strong LB, Urvina AH, Zheng B, Rijal A, Smith SV, Yu H, Roman RJ, Fan F. Luseogliflozin, a sodium-glucose cotransporter-2 inhibitor, reverses cerebrovascular dysfunction and cognitive impairments in 18-mo-old diabetic animals. Am J Physiol Heart Circ Physiol 2022; 322:H246-H259. [PMID: 34951541 PMCID: PMC8759958 DOI: 10.1152/ajpheart.00438.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 11/29/2021] [Accepted: 12/15/2021] [Indexed: 02/03/2023]
Abstract
Diabetes mellitus (DM) is a leading risk factor for age-related dementia, but the mechanisms involved are not well understood. We previously discovered that hyperglycemia induced impaired myogenic response (MR) and cerebral blood flow (CBF) autoregulation in 18-mo-old DM rats associated with blood-brain barrier (BBB) leakage, impaired neurovascular coupling, and cognitive impairment. In the present study, we examined whether reducing plasma glucose with a sodium-glucose cotransporter-2 inhibitor (SGLT2i) luseogliflozin can ameliorate cerebral vascular and cognitive function in diabetic rats. Plasma glucose and HbA1c levels of 18-mo-old DM rats were reduced, and blood pressure was not altered after treatment with luseogliflozin. SGLT2i treatment restored the impaired MR of middle cerebral arteries (MCAs) and parenchymal arterioles and surface and deep cortical CBF autoregulation in DM rats. Luseogliflozin treatment also rescued neurovascular uncoupling, reduced BBB leakage and cognitive deficits in DM rats. However, SGLT2i did not have direct constrictive effects on vascular smooth muscle cells and MCAs isolated from normal rats, although it decreased reactive oxygen species production in cerebral vessels of DM rats. These results provide evidence that normalization of hyperglycemia with an SGLT2i can reverse cerebrovascular dysfunction and cognitive impairments in rats with long-standing hyperglycemia, possibly by ameliorating oxidative stress-caused vascular damage.NEW & NOTEWORTHY This study demonstrates that luseogliflozin, a sodium-glucose cotransporter-2 inhibitor, improved CBF autoregulation in association with reduced vascular oxidative stress and AGEs production in the cerebrovasculature of 18-mo-old DM rats. SGLT2i also prevented BBB leakage, impaired functional hyperemia, neurodegeneration, and cognitive impairment seen in DM rats. Luseogliflozin did not have direct constrictive effects on VSMCs and MCAs isolated from normal rats. These results provide evidence that normalization of hyperglycemia with an SGLT2i can reverse cerebrovascular dysfunction and cognitive impairments in rats with long-standing hyperglycemia, possibly by ameliorating oxidative stress-caused vascular damage.
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Affiliation(s)
- Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Feng Jiao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jane J Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Reece F Crumpler
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joshua Jefferson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ya Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Parker S Elliott
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Kirby N Thomas
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Luke B Strong
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Austin H Urvina
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Arjun Rijal
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Stanley V Smith
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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11
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Abstract
ABSTRACT In the context of diabetes mellitus, various pathological changes cause tissue ischemia and hypoxia, which can lead to the compensatory formation of neovascularization. However, disorders of the internal environment and dysfunctions of various cells contribute to the dysfunction of neovascularization. Although the problems of tissue ischemia and hypoxia have been partially solved, neovascularization also causes many negative effects. In the process of small blood vessel renewal, pericytes are extremely important for maintaining the normal growth and maturation of neovascularization. Previously, our understanding of pericytes was very limited, and the function of pericytes was not yet clear. Recently, multiple new functions of pericytes have been identified, affecting various processes in angiogenesis and relating to various diseases. Therefore, the importance of pericytes has gradually become apparent. This article presents the latest research progress on the role of pericytes in diabetic angiogenesis, characterizes pericytes, summarizes various potential therapeutic targets, and highlights research directions for the future treatment of various diabetes-related diseases.
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12
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Crumpler R, Roman RJ, Fan F. Capillary Stalling: A Mechanism of Decreased Cerebral Blood Flow in AD/ADRD. JOURNAL OF EXPERIMENTAL NEUROLOGY 2021; 2:149-153. [PMID: 35028643 PMCID: PMC8754422 DOI: 10.33696/neurol.2.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alzheimer's Disease (AD) and Alzheimer's Disease-Related Dementias (ADRD) are debilitating conditions that are highly associated with aging populations, especially those with comorbidities such as diabetes and hypertension. In addition to the classical pathological findings of AD, such as beta-amyloid (Aβ) accumulation and tau hyperphosphorylation, vascular dysfunction is also associated with the progression of the disease. Vascular dysfunction in AD is associated with decreased cerebral blood flow (CBF). Impaired CBF is an early and persistent symptom of AD/ADRD and is thought to be associated with deficient autoregulation and neurovascular coupling. Another recently elucidated mechanism that contributes to cerebral hypoperfusion is capillary stalling, or the temporary arrest of capillary blood flow usually precipitated by a stalled leukocyte or constriction of actin-containing capillary pericytes. Stalled capillaries are associated with decreased CBF and impaired cognitive performance. AD/ADRD are associated with chronic, low-level inflammation, which contributes to capillary stalling by increased cell adhesion molecules, circulating leukocytes, and reactive oxygen species production. Recent research has shed light on potential targets to decrease capillary stalling in AD mice. Separate inhibition of Ly6G and VEGF-A has been shown to decrease capillary stalling and increase CBF in AD mice. These results suggest that targeting stalled capillaries could influence the outcome of AD and potentially be a target for future therapies.
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Affiliation(s)
- Reece Crumpler
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
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