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Zare A, Shamshiripour P, Lotfi S, Shahin M, Rad VF, Moradi AR, Hajiahmadi F, Ahmadvand D. Clinical theranostics applications of photo-acoustic imaging as a future prospect for cancer. J Control Release 2022; 351:805-833. [DOI: 10.1016/j.jconrel.2022.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 10/31/2022]
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Pham T, Blaney G, Sassaroli A, Fernandez C, Fantini S. Sensitivity of frequency-domain optical measurements to brain hemodynamics: simulations and human study of cerebral blood flow during hypercapnia. BIOMEDICAL OPTICS EXPRESS 2021; 12:766-789. [PMID: 33680541 PMCID: PMC7901322 DOI: 10.1364/boe.412766] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/04/2020] [Accepted: 12/16/2020] [Indexed: 05/20/2023]
Abstract
This study characterizes the sensitivity of noninvasive measurements of cerebral blood flow (CBF) by using frequency-domain near-infrared spectroscopy (FD-NIRS) and coherent hemodynamics spectroscopy (CHS). We considered six FD-NIRS methods: single-distance intensity and phase (SDI and SDϕ), single-slope intensity and phase (SSI and SSϕ), and dual-slope intensity and phase (DSI and DSϕ). Cerebrovascular reactivity (CVR) was obtained from the relative change in measured CBF during a step hypercapnic challenge. Greater measured values of CVR are assigned to a greater sensitivity to cerebral hemodynamics. In a first experiment with eight subjects, CVRSDϕ was greater than CVRSDI (p < 0.01), whereas CVRDSI and CVRDSϕ showed no significant difference (p > 0.5). In a second experiment with four subjects, a 5 mm scattering layer was added between the optical probe and the scalp tissue to increase the extracerebral layer thickness (L ec ), which caused CVRDSϕ to become significantly greater than CVRDSI (p < 0.05). CVRSS measurements yielded similar results as CVRDS measurements but with a greater variability, possibly resulting from instrumental artifacts in SS measurements. Theoretical simulations with two-layered media confirmed that, if the top (extracerebral) layer is more scattering than the bottom (brain) layer, the relative values of CVRDSI and CVRDSϕ depend on L ec . Specifically, the sensitivity to the brain is greater for DSI than DSϕ for a thin extracerebral layer (L ec < 13 mm), whereas it is greater for DSϕ than DSI for a thicker extracerebral layer.
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Affiliation(s)
- Thao Pham
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Giles Blaney
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Angelo Sassaroli
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Cristianne Fernandez
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
| | - Sergio Fantini
- Tufts University, Department of Biomedical Engineering, 4 Colby Street, Medford, MA 02155, USA
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Li Y, Li R, Liu M, Nie Z, Muir ER, Duong TQ. MRI study of cerebral blood flow, vascular reactivity, and vascular coupling in systemic hypertension. Brain Res 2020; 1753:147224. [PMID: 33358732 DOI: 10.1016/j.brainres.2020.147224] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/30/2020] [Accepted: 11/27/2020] [Indexed: 01/14/2023]
Abstract
Chronic hypertension alters cerebrovascular function, which can lead to neurovascular pathologies and increased susceptibility to neurological disorders. The purpose of this study was to utilize in vivo MRI methods with corroborating immunohistology to evaluate neurovascular dysfunction due to progressive chronic hypertension. The spontaneously hypertensive rat (SHR) model at different stages of hypertension was studied to evaluate: i) basal cerebral blood flow (CBF), ii) cerebrovascular reactivity (CVR) assessed by CBF and blood-oxygenation level dependent (BOLD) signal changes to hypercapnia, iii) neurovascular coupling from CBF and BOLD changes to forepaw stimulation, and iv) damage of neurovascular unit (NVU) components (microvascular, astrocyte and neuron densities). Comparisons were made with age-matched normotensive Wistar Kyoto (WKY) rats. In 10-week SHR (mild hypertension), basal CBF was higher (p < 0.05), CVR trended higher, and neurovascular coupling response was higher (p < 0.05), compared to normotensive rats. In 40-week SHR (severe hypertension), basal CBF, CVR, and neurovascular coupling response were reversed to similar or below normotensive rats, and were significantly different from 10-week SHR (p < 0.05). Immunohistological analysis found significantly reduced microvascular density, increased astrocytes, and reduced neuronal density in SHR at 40 weeks (p < 0.05) but not at 10 weeks (p > 0.05) in comparison to age-matched controls. In conclusion, we observed a bi-phasic basal CBF, CVR and neurovascular coupling response from early to late hypertension using in vivo MRI, with significant changes prior to changes in the NVU components from histology. MRI provides clinically relevant data that might be useful to characterize neurovascular pathogenesis on the brain in hypertension.
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Affiliation(s)
- Yunxia Li
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Renren Li
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Meng Liu
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhiyu Nie
- Department of Neurology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Eric R Muir
- Department of Radiology, Renaissance School of Medicine, Stony Brook University Hospital, Stony Brook, NY, USA
| | - Tim Q Duong
- Department of Radiology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, USA.
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Cerebral Blood Flow in SHR Rats after Transplantation of Mesenchymal Stem Cells. Bull Exp Biol Med 2019; 166:586-590. [PMID: 30783841 DOI: 10.1007/s10517-019-04396-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Indexed: 10/27/2022]
Abstract
Intracerebral transplantation of mesenchymal stem cells to 6- and 12-month-old SHR rats induced angiogenesis in the pia mater. In 6-months-old SHR rats, perfusion in the brain tissue after cell transplantation considerably increased, while in 12-month-old rats it remained practically unchanged. We also observed marked activation of regulatory processes in the cerebral vascular system, most pronounced in 12-month-old rats. Neurogenic and myogenic tone of cerebral vessels increased significantly, while endothelium-dependent tone slightly decreased. The increase in neurogenic and myogenic tone of blood vessels in SHR rats at the age of 6 and 12 months after transplantation of stem cells can be explained by the formation of new smooth muscle cells in the pre-existing arteries walls. Greater muscle mass developed stronger force and contributed to narrowing of the arterial lumen, as a result, there was no increase in blood flow despite the downstream angiogenesis. A slight decrease in endothelium-dependent tone can be explained by increased production of vasodilators by newly formed endothelial cells.
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Evaluation of renal oxygen saturation using photoacoustic imaging for the early prediction of chronic renal function in a model of ischemia-induced acute kidney injury. PLoS One 2018; 13:e0206461. [PMID: 30557371 PMCID: PMC6296502 DOI: 10.1371/journal.pone.0206461] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/13/2018] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To evaluate the utility of photoacoustic imaging in measuring changes in renal oxygen saturation after ischemia-induced acute kidney injury, and to compare these measurements with histological findings and serum levels of kidney function. MATERIAL AND METHODS Acute kidney injury was induced by clamping the left renal pedicle in C57Bl/6 mice, with a 35-min ischemic period used to induce mild renal injury (14 mice) and a 50-min period for severe injury (13 mice). The oxygen saturation was measured before induction, and at 5 time-points over the first 48 h after induction, starting at 4 h after induction. Oxygen saturation, histological score, kidney volume, and the 24 h creatinine clearance rate and serum blood urea nitrogen were also measured on day 28. Between-group differences were evaluated using a Mann-Whitney U-test and Dunn's multiple comparisons. The association between oxygen saturation and measured variables was evaluated using Spearman's correlation. A receiver operator characteristic curve was constructed from oxygen saturation values at 24 h after heminephrectomy to predict chronic renal function. RESULTS The oxygen saturation was higher in the mild than severe renal injury group at 24 h after induction (73.7% and 66.9%, respectively, P<0.05). Between-group comparison on day 28 revealed a higher kidney volume (P = 0.007), lower tubular injury (P<0.001), lower serum level of blood urea nitrogen level (P = 0.016), and lower 24 h creatinine clearance rate (P = 0.042) in the mild compared with the severe injury group. The oxygen saturation at 24 h correlated with the 24 h creatinine clearance rate (P = 0.036) and serum blood urea nitrogen (P<0.001) on day 28, with an area under the receiver operating curve of 0.825. CONCLUSION Oxygen saturation, measured by photoacoustic imaging at 24 h after acute kidney injury can predict the extent of subsequent histological alterations in the kidney early after injury.
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Basal LA, Yan Y, Shen Y, Haacke EM, Mehrmohammadi M, Allen MJ. Oxidation-Responsive, Eu II/III-Based, Multimodal Contrast Agent for Magnetic Resonance and Photoacoustic Imaging. ACS OMEGA 2017; 2:800-805. [PMID: 28393130 PMCID: PMC5377279 DOI: 10.1021/acsomega.6b00514] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/21/2017] [Indexed: 05/08/2023]
Abstract
We report, for the first time, a multimodal, oxidation-responsive contrast agent for magnetic resonance imaging and photoacoustic imaging that uses the differences in the properties between Eu in the +2 and +3 oxidation states. The enhancement of contrast in T1-weighted magnetic resonance and photoacoustic imaging was observed in the +2 but not in the +3 oxidation state, and the complex is a known chemical exchange saturation transfer agent for magnetic resonance imaging in the +3 oxidation state.
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Affiliation(s)
- Lina A. Basal
- Department
of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Yan Yan
- Department
of Biomedical Engineering, Wayne State University, 818 W. Hancock, Detroit, Michigan 48201, United States
| | - Yimin Shen
- Department
of Radiology, Wayne State University, Detroit, Michigan 48201, United States
| | - E. Mark Haacke
- Department
of Radiology, Wayne State University, Detroit, Michigan 48201, United States
- Barbara
Ann Karmanos Cancer Institute, Detroit, Michigan 48201, United States
| | - Mohammad Mehrmohammadi
- Department
of Biomedical Engineering, Wayne State University, 818 W. Hancock, Detroit, Michigan 48201, United States
- Barbara
Ann Karmanos Cancer Institute, Detroit, Michigan 48201, United States
| | - Matthew J. Allen
- Department
of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
- Barbara
Ann Karmanos Cancer Institute, Detroit, Michigan 48201, United States
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Marowsky A, Haenel K, Bockamp E, Heck R, Rutishauser S, Mule N, Kindler D, Rudin M, Arand M. Genetic enhancement of microsomal epoxide hydrolase improves metabolic detoxification but impairs cerebral blood flow regulation. Arch Toxicol 2016; 90:3017-3027. [PMID: 26838043 PMCID: PMC5104800 DOI: 10.1007/s00204-016-1666-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/06/2016] [Indexed: 01/05/2023]
Abstract
Microsomal epoxide hydrolase (mEH) is a detoxifying enzyme for xenobiotic compounds. Enzymatic activity of mEH can be greatly increased by a point mutation, leading to an E404D amino acid exchange in its catalytic triad. Surprisingly, this variant is not found in any vertebrate species, despite the obvious advantage of accelerated detoxification. We hypothesized that this evolutionary avoidance is due to the fact that the mEH plays a dualistic role in detoxification and control of endogenous vascular signaling molecules. To test this, we generated mEH E404D mice and assessed them for detoxification capacity and vascular dynamics. In liver microsomes from these mice, turnover of the xenobiotic compound phenanthrene-9,10-oxide was four times faster compared to WT liver microsomes, confirming accelerated detoxification. mEH E404D animals also showed faster metabolization of a specific class of endogenous eicosanoids, arachidonic acid-derived epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs). Significantly higher DHETs/EETs ratios were found in mEH E404D liver, urine, plasma, brain and cerebral endothelial cells compared to WT controls, suggesting a broad impact of the mEH mutant on endogenous EETs metabolism. Because EETs are strong vasodilators in cerebral vasculature, hemodynamics were assessed in mEH E404D and WT cerebral cortex and hippocampus using cerebral blood volume (CBV)-based functional magnetic resonance imaging (fMRI). Basal CBV0 levels were similar between mEH E404D and control mice in both brain areas. But vascular reactivity and vasodilation in response to the vasodilatory drug acetazolamide were reduced in mEH E404D forebrain compared to WT controls by factor 3 and 2.6, respectively. These results demonstrate a critical role for mEH E404D in vasodynamics and suggest that deregulation of endogenous signaling pathways is the undesirable gain of function associated with the E404D variant.
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Affiliation(s)
- Anne Marowsky
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Karen Haenel
- Institute of Complex Systems (ICS-6), Research Center Julich, Wilhelm-Johnen-Straße, 52425, Julich, Germany
| | - Ernesto Bockamp
- Institute of Translational Immunology, University of Mainz, Obere Zahlbacherstrasse 63, 55131, Mainz, Germany
| | - Rosario Heck
- Institute of Translational Immunology, University of Mainz, Obere Zahlbacherstrasse 63, 55131, Mainz, Germany
| | - Sibylle Rutishauser
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Nandkishor Mule
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Diana Kindler
- Institute for Biomedical Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Markus Rudin
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Institute for Biomedical Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Michael Arand
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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Bogdanov AA, Dixon AJ, Gupta S, Zhang L, Zheng S, Shazeeb MS, Zhang S, Klibanov AL. Synthesis and Testing of Modular Dual-Modality Nanoparticles for Magnetic Resonance and Multispectral Photoacoustic Imaging. Bioconjug Chem 2015; 27:383-90. [PMID: 26603129 DOI: 10.1021/acs.bioconjchem.5b00633] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Magnetic resonance (MR) and photoacoustic (PA) imaging are currently being investigated as complementing strategies for applications requiring sensitive detection of cells in vivo. While combined MR/PAI detection of cells requires biocompatible cell labeling probes, water-based synthesis of dual-modality MR/PAI probes presents significant technical challenges. Here we describe facile synthesis and characterization of hybrid modular dextran-stabilized gold/iron oxide (Au-IO) multimetallic nanoparticles (NP) enabling multimodal imaging of cells. The stable association between the IO and gold NP was achieved by priming the surface of dextran-coated IO with silver NP resulting from silver(I) reduction by aldehyde groups, which are naturally present within the dextran coating of IO at the level of 19-23 groups/particle. The Au-IO NP formed in the presence of silver-primed Au-IO were stabilized by using partially thiolated MPEG5-gPLL graft copolymer carrying residual amino groups. This stabilizer served as a carrier of near-infrared fluorophores (e.g., IRDye 800RS) for multispectral PA imaging. Dual modality imaging experiments performed in capillary phantoms of purified Au-IO-800RS NPs showed that these NPs were detectible using 3T MRI at a concentration of 25 μM iron. PA imaging achieved approximately 2.5-times higher detection sensitivity due to strong PA signal emissions at 530 and 770 nm, corresponding to gold plasmons and IRDye integrated into the coating of the hybrid NPs, respectively, with no "bleaching" of PA signal. MDA-MB-231 cells prelabeled with Au-IO-800RS retained plasma membrane integrity and were detectable by using both MR and dual-wavelength PA at 49 ± 3 cells/imaging voxel. We believe that modular assembly of multimetallic NPs shows promise for imaging analysis of engineered cells and tissues with high resolution and sensitivity.
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Affiliation(s)
| | - Adam J Dixon
- Department of Biomedical Engineering, University of Virginia , Charlottesville, Virginia 22904, United States
| | | | | | | | | | | | - Alexander L Klibanov
- Department of Biomedical Engineering, University of Virginia , Charlottesville, Virginia 22904, United States
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Cerebral angiography, blood flow and vascular reactivity in progressive hypertension. Neuroimage 2015; 111:329-37. [PMID: 25731987 DOI: 10.1016/j.neuroimage.2015.02.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/18/2015] [Accepted: 02/22/2015] [Indexed: 11/23/2022] Open
Abstract
Chronic hypertension alters cerebral vascular morphology, cerebral blood flow (CBF), cerebrovascular reactivity, and increses susceptibility to neurological disorders. This study evaluated: i) the lumen diameters of major cerebral and downstream arteries using magnetic resonance angiography, ii) basal CBF, and iii) cerebrovascular reactivity to hypercapnia of multiple brain regions using arterial-spin-labeling technique in spontaneously hypertensive rats (SHR) at different stages. Comparisons were made with age-matched normotensive Wistar Kyoto (WKY) rats. In 10-week SHR, lumen diameter started to reduce, basal CBF, and hypercapnic CBF response were higher from elevated arterial blood pressure, but there was no evidence of stenosis, compared to age-matched WKY. In 20-week SHR, lumen diameter remained reduced, CBF returned toward normal from vasoconstriction, hypercapnic CBF response reversed and became smaller, but without apparent stenosis. In 40-week SHR, lumen diameter remained reduced and basal CBF further decreased, resulting in larger differences compared to WKY. There was significant stenosis in main supplying cerebral vessels. Hypercapnic CBF response further decreased, with some animals showing negative hypercapnic CBF responses in some brain regions, indicative of compromised cerebrovascular reserve. The territory with negative hypercapnia CBF responses corresponded with the severity of stenosis in arteries that supplied those territories. We also found enlargement of downstream vessels and formation of collateral vessels as compensatory responses to stenosis of upstream vessels. The middle cerebral and azygos arteries were amongst the most susceptible to hypertension-induced changes. Multimodal MRI provides clinically relevant data that might be useful to characterize disease pathogenesis, stage disease progression, and monitor treatment effects in hypertension.
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Rich LJ, Seshadri M. Photoacoustic imaging of vascular hemodynamics: validation with blood oxygenation level-dependent MR imaging. Radiology 2014; 275:110-8. [PMID: 25423146 DOI: 10.1148/radiol.14140654] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE To noninvasively assess vascular hemodynamics with photoacoustic imaging (PAI) and blood oxygenation level-dependent (BOLD) magnetic resonance (MR) imaging in phantoms and in an animal model. MATERIALS AND METHODS In vivo studies were performed with institutional animal care and use committee approval. In vitro experiments were performed by using a tissue-mimicking phantom in multiple oxygenation conditions (n = 6) to compare PAI measurements and BOLD MR imaging measurements. PAI and T2-weighted spin-echo-based BOLD MR imaging were performed to assess tumor response to carbogen (95% O2, 5% CO2) in mice with head and neck tumors before (n = 11) and after (n = 9) treatment with a vascular disrupting agent (VDA). Two-tailed Pearson correlation analysis was performed to determine the correlation between the parameters measured with PAI and BOLD MR imaging in vitro. Two-tailed paired t tests were used to compare change in tumor hemoglobin oxygen saturation (sO2) levels and BOLD signal in response to carbogen. Changes in PAI and BOLD signal intensity before and after VDA treatment were analyzed for significance by using analysis of variance with repeated measures. RESULTS Phantom measurements yielded good correlation between photoacoustically derived sO2 levels and BOLD signal intensity (r = 0.937, P = .005) and partial pressure of oxygen (r = 0.981, P = .005). In vivo hemodynamic response to carbogen was characterized by a significant increase in tumor sO2 levels (P = .003) and BOLD signal (P = .001). When compared with pretreatment estimates, treatment with VDA resulted in a significant reduction in the tumor hemodynamic response to carbogen at PAI (P = .030). CONCLUSION Carbogen-based functional imaging with PAI and BOLD MR imaging enables monitoring of early changes in tumor hemodynamics after vascular targeted therapy.
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Affiliation(s)
- Laurie J Rich
- From the Departments of Molecular and Cellular Biophysics (L.J.R., M.S.), Pharmacology and Therapeutics (M.S.) and Head and Neck Surgery (M.S.), Roswell Park Cancer Institute, CGP L4-314, Elm and Carlton Streets, Buffalo, NY 14263
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Vascular response to acetazolamide decreases as a function of age in the arcA beta mouse model of cerebral amyloidosis. Neurobiol Dis 2010; 40:284-92. [PMID: 20600914 DOI: 10.1016/j.nbd.2010.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 05/17/2010] [Accepted: 06/11/2010] [Indexed: 11/23/2022] Open
Abstract
Deposition of beta-amyloid along cerebral vessels is found in most patients suffering from Alzheimer's disease. The effects of cerebral amyloid angiopathy (CAA) on the function of cerebral blood vessels were analyzed applying cerebral blood volume (CBV)-based fMRI to transgenic arcA beta mice. In a cortical brain region of interest (ROI), displaying high CAA, arcA beta mice older than 16 months showed reduced response to the vasodilatory substance acetazolamide compared to age-matched wild-type animals, both with regard to rate (vascular reactivity) and extent of vasodilation (maximal vasodilation). In a subcortical ROI, displaying little CAA, no genotype-specific decrease was observed, but maximal vasodilation decreased with age in arcA beta and wild-types. These findings indicate that vascular beta-amyloid deposits reduce the capacity of cerebral blood vessels to dilate upon demand, supporting the hypothesis that vascular beta-amyloid contributes to hypoperfusion and neurological deficits observed in AD and CAA. High diagnostic accuracy of the combined readouts in detecting vascular dysfunction in arcA beta mice was found.
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Abstract
The risk for dementia, a major contributor to incapacitation and institutionalization, rises rapidly as we age, doubling every 5 y after age 65. Tens of millions of new Alzheimer's disease (AD) and other dementia cases are projected as elderly populations increase around the world, creating a projected dementia epidemic for which most nations are not prepared. Thus, there is an urgent need for prevention approaches that are safe, effective, and affordable. This review addresses the potential of one promising candidate, the (n-3) fatty acid docosahexaenoic acid (DHA), which appears to slow pathogenesis of AD and possibly vascular dementia. DHA is pleiotropic, acting at multiple steps to reduce the production of the beta-amyloid peptide, widely believed to initiate AD. DHA moderates some of the kinases that hyperphosphorylate the tau-protein, a component of the neurofibrillary tangle. DHA may help suppress insulin/neurotrophic factor signaling deficits, neuroinflammation, and oxidative damage that contribute to synaptic loss and neuronal dysfunction in dementia. Finally, DHA increases brain levels of neuroprotective brain-derived neurotrophic factor and reduces the (n-6) fatty acid arachidonate and its prostaglandin metabolites that have been implicated in promoting AD. Clinical trials suggest that DHA or fish oil alone can slow early stages of progression, but these effects may be apolipoprotein E genotype specific, and larger trials with very early stages are required to prove efficacy. We advocate early intervention in a prodromal period with nutrigenomically defined subjects with an appropriately designed nutritional supplement, including DHA and antioxidants.
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Affiliation(s)
- Greg M Cole
- Departments of Medicine and Neurology, University of California, Los Angeles, CA 90095, USA.
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