1
|
Xue L, Ouyang W, Qi X, Zhang X, Li B, Zhang X, Cui L. Modified histological staining for the identification of arterial and venous segments of brain microvessels. J Neurosci Methods 2024; 409:110214. [PMID: 38960332 DOI: 10.1016/j.jneumeth.2024.110214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/13/2024] [Accepted: 06/28/2024] [Indexed: 07/05/2024]
Abstract
BACKGROUND This study aimed to develop a modified histochemical staining technique to successfully identify arterial and venous segments of brain microvessels. NEW METHOD Gelatin/red ink-alkaline phosphatase-oil red O (GIAO) staining was developed from the traditional gelatin-ink perfusion method. Oil red Chinese ink for brush writing and painting mixed with gelatin was used to label cerebral vascular lumens. Subsequently, alkaline phosphatase staining was used to label endothelial cells on the arterial segments of cerebral microvessels. Thereafter, the red ink color in vessel lumens was highlighted with oil red O staining. RESULTS The arterial segments of the brain microvessels exhibited red lumens surrounded by dark blue walls, while the venous segments were bright red following GIAO staining. Meanwhile, the nerve fiber bundles were stained brownish-yellow, and the nuclei appeared light green under light microscope. After cerebral infarction, we used GIAO staining to determine angiogenesis features and detected notable vein proliferation inside the infarct core. Moreover, GIAO staining in conjunction with hematoxylin staining was performed to assess the infiltration of foamy macrophages. COMPARISON WITH EXISTING METHOD Red Chinese ink enabled subsequent multiple color staining on brain section. Oil red O was introduced to improved the resolution and contrast between arterial and venous segments of microvessels. CONCLUSION With excellent resolution, GIAO staining effectively distinguished arterial and venous segments of microvessels in both normal and ischemic brain tissue. GIAO staining, as described in the present study, will be useful for histological investigations of microvascular bed alterations in a variety of brain disorders.
Collapse
Affiliation(s)
- Luping Xue
- Department of Neurology, The Second Hospital of Hebei medical university, Shijiazhuang, Hebei 050000, China
| | - Wei Ouyang
- Department of Neurology, The Second Hospital of Hebei medical university, Shijiazhuang, Hebei 050000, China
| | - Xiaoru Qi
- Interventional Department of Cerebral Vascular Disease, Cangzhou People's Hospital, Cangzhou, Hebei 061000, China
| | - Xiao Zhang
- Department of Neurology, The Second Hospital of Hebei medical university, Shijiazhuang, Hebei 050000, China
| | - Baodong Li
- Department of Neurology, Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, Hebei 061000, China.
| | - Xiangjian Zhang
- Department of Neurology, The Second Hospital of Hebei medical university, Shijiazhuang, Hebei 050000, China; Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050000, China
| | - Lili Cui
- Department of Neurology, The Second Hospital of Hebei medical university, Shijiazhuang, Hebei 050000, China; Hebei Key Laboratory of Vascular Homeostasis, Shijiazhuang, Heibei 050000, China.
| |
Collapse
|
2
|
Noh K, Liu X, Wei C. Optimizing transcardial perfusion of small molecules and biologics for brain penetration and biodistribution studies in rodents. Biopharm Drug Dispos 2023; 44:71-83. [PMID: 35508078 DOI: 10.1002/bdd.2317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 11/06/2022]
Abstract
Efficiently removing blood from the brain vasculature is critical to evaluate accurately the brain penetration and biodistribution of drug candidates, especially for biologics as their blood concentrations are substantially higher than the brain concentrations. Transcardial perfusion has been used widely to remove residual blood in the brain; however, the perfusion conditions (such as the perfusion rate and time) reported in the literature are quite varied, and the performance of these methods on blood removal has not been investigated thoroughly. In this study, the effectiveness of the perfusion conditions was assessed by measuring brain hemoglobin levels. Sodium nitrite (NaNO2 ) as an additive in the perfusate was evaluated at different concentrations. Blood removal was significantly improved with 2% NaNO2 over a 20 min perfusion in mouse without disrupting the integrity of the blood-brain barrier (BBB). In mice, the optimized perfusion method significantly lowered the measured brain-to-plasma ratio (Kp,brain ) for monoclonal antibodies due to the removal of blood contamination and small molecules with a moderate-to-high BBB permeability and with a high brain-unbound-fraction (fu,brain ) presumably due to flux out of the brain during perfusion. Perfusion with or without NaNO2 clearly removed the residual blood in rat brain but with no difference observed in Kp,brain between the perfusion groups with or without 2% NaNO2 . In conclusion, a perfusion method was successfully developed to evaluate the brain penetration of small molecules and biologics in rodents for the first time. The transcardial perfusion with 2% NaNO2 effectively removed the residual blood in the brain and significantly improved the assessment of brain penetration of biologics. For small molecules, however, transcardial perfusion may not be performed, as small molecule compounds could be washed away from the brain by the perfusion procedure.
Collapse
Affiliation(s)
- Keumhan Noh
- Drug Metabolism and Pharmacokinetics, Biogen, Cambridge, Massachusetts, USA
| | - Xingrong Liu
- Drug Metabolism and Pharmacokinetics, Biogen, Cambridge, Massachusetts, USA
| | - Cong Wei
- Drug Metabolism and Pharmacokinetics, Biogen, Cambridge, Massachusetts, USA
| |
Collapse
|
3
|
Yousef EN, Dasgupta PK, Horn SA, Shelor CP, Roy S. Geometric characterization of polymeric capillaries. Anal Chim Acta 2022; 1229:340345. [PMID: 36156221 DOI: 10.1016/j.aca.2022.340345] [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: 06/27/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 11/01/2022]
Abstract
There are few methods in the literature to measure the inner diameter of very small capillaries. Although silica capillaries are more commonly used, synthetic polymer capillaries are preferred in some applications. The technology for producing them is not as mature. Aside from the absolute value of the inner diameter, the circularity, concentricity (a quantitative index is defined here for the first time) and the bore uniformity of such capillaries are of interest. Beyond microscopy, we describe multiple methods that determine the capillary inner diameter, averaged over a given length. The measurements variously depended on the capillary internal volume, length and cross section, and the resistance to fluid flow. The different approaches produced mutually consistent results. We show that when the internal diameter is not uniform, the different dependence on diameter that two such methods may exhibit, can be exploited to determine the true mean diameter as well as its variance. Finally, for open tubular liquid chromatography, where performance acutely depends on the inner diameter, we surprisingly find that while the mean i.d. may be the dominant determinant of efficiency, bore variance has little to no effect on the performance.
Collapse
Affiliation(s)
- Enas N Yousef
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States
| | - Purnendu K Dasgupta
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States.
| | - Seth A Horn
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States
| | - C Phillip Shelor
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019-0065, United States
| | - Souvik Roy
- Department of Mathematics, University of Texas at Arlington, Arlington, TX, 76019-0408, United States
| |
Collapse
|
4
|
Modeling the Effect of Binding Kinetics in Spatial Drug Distribution in the Brain. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2021; 2021:5533886. [PMID: 34285707 PMCID: PMC8275424 DOI: 10.1155/2021/5533886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 11/28/2022]
Abstract
A 3-dimensional mathematical model is developed to determine the effect of drug binding kinetics on the spatial distribution of a drug within the brain. The key components, namely, transport across the blood-brain barrier (BBB), drug distribution in the brain extracellular fluid (ECF), and drug binding kinetics are coupled with the bidirectional bulk flow of the brain ECF to enhance the visualization of drug concentration in the brain. The model is developed based on the cubical volume of a brain unit, which is a union of three subdomains: the brain ECF, the BBB, and the blood plasma. The model is a set of partial differential equations and the associated initial and boundary conditions through which the drug distribution process in the mentioned subdomains is described. Effects of drug binding kinetics are investigated by varying the binding parameter values for both nonspecific and specific binding sites. All variations of binding parameter values are discussed, and the results show the improved visualization of the effect of binding kinetics in the drug distribution within the brain. For more realistic visualization, we suggest incorporating more brain components that make up the large volume of the brain tissue.
Collapse
|
5
|
Basmadjian OM, Occhieppo VB, Marchese NA, Silvero C MJ, Becerra MC, Baiardi G, Bregonzio C. Amphetamine Induces Oxidative Stress, Glial Activation and Transient Angiogenesis in Prefrontal Cortex via AT 1-R. Front Pharmacol 2021; 12:647747. [PMID: 34012397 PMCID: PMC8126693 DOI: 10.3389/fphar.2021.647747] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/30/2021] [Indexed: 01/21/2023] Open
Abstract
Background: Amphetamine (AMPH) alters neurons, glia and microvessels, which affects neurovascular unit coupling, leading to disruption in brain functions such as attention and working memory. Oxidative stress plays a crucial role in these alterations. The angiotensin type I receptors (AT1-R) mediate deleterious effects, such as oxidative/inflammatory responses, endothelial dysfunction, neuronal oxidative damage, alterations that overlap with those observed from AMPH exposure. Aims: The aim of this study was to evaluate the AT1-R role in AMPH-induced oxidative stress and glial and vascular alterations in the prefrontal cortex (PFC). Furthermore, we aimed to evaluate the involvement of AT1-R in the AMPH-induced short-term memory and working memory deficit. Methods: Male Wistar rats were repeatedly administered with the AT1-R blocker candesartan (CAND) and AMPH. Acute oxidative stress in the PFC was evaluated immediately after the last AMPH administration by determining lipid and protein peroxidation. After 21 off-drug days, long-lasting alterations in the glia, microvessel architecture and to cognitive tasks were evaluated by GFAP, CD11b and von Willebrand immunostaining and by short-term and working memory assessment. Results: AMPH induced acute oxidative stress, long-lasting glial reactivity in the PFC and a working memory deficit that were prevented by AT1-R blockade pretreatment. Moreover, AMPH induces transient angiogenesis in PFC via AT1-R. AMPH did not affect short-term memory. Conclusion: Our results support the protective role of AT1-R blockade in AMPH-induced oxidative stress, transient angiogenesis and long-lasting glial activation, preserving working memory performance.
Collapse
Affiliation(s)
- Osvaldo M Basmadjian
- Departamento de Farmacología, Facultad de Ciencias Químicas, Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Victoria B Occhieppo
- Departamento de Farmacología, Facultad de Ciencias Químicas, Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Natalia A Marchese
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Departamento de Química Biológica "Ranwel Caputto", Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M Jazmin Silvero C
- Instituto Multidisciplinario de Biología Vegetal (IMBIV-CONICET) Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María Cecilia Becerra
- Instituto Multidisciplinario de Biología Vegetal (IMBIV-CONICET) Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Gustavo Baiardi
- Laboratorio de Neurofarmacología, (IIBYT-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina.,Facultad de Ciencias Químicas, Universidad Católica de Córdoba, Córdoba, Argentina
| | - Claudia Bregonzio
- Departamento de Farmacología, Facultad de Ciencias Químicas, Instituto de Farmacología Experimental Córdoba (IFEC-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| |
Collapse
|
6
|
Vendel E, Rottschäfer V, de Lange ECM. A 3D brain unit model to further improve prediction of local drug distribution within the brain. PLoS One 2020; 15:e0238397. [PMID: 32966285 PMCID: PMC7511021 DOI: 10.1371/journal.pone.0238397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/15/2020] [Indexed: 12/14/2022] Open
Abstract
The development of drugs targeting the brain still faces a high failure rate. One of the reasons is a lack of quantitative understanding of the complex processes that govern the pharmacokinetics (PK) of a drug within the brain. While a number of models on drug distribution into and within the brain is available, none of these addresses the combination of factors that affect local drug concentrations in brain extracellular fluid (brain ECF). Here, we develop a 3D brain unit model, which builds on our previous proof-of-concept 2D brain unit model, to understand the factors that govern local unbound and bound drug PK within the brain. The 3D brain unit is a cube, in which the brain capillaries surround the brain ECF. Drug concentration-time profiles are described in both a blood-plasma-domain and a brain-ECF-domain by a set of differential equations. The model includes descriptions of blood plasma PK, transport through the blood-brain barrier (BBB), by passive transport via paracellular and transcellular routes, and by active transport, and drug binding kinetics. The impact of all these factors on ultimate local brain ECF unbound and bound drug concentrations is assessed. In this article we show that all the above mentioned factors affect brain ECF PK in an interdependent manner. This indicates that for a quantitative understanding of local drug concentrations within the brain ECF, interdependencies of all transport and binding processes should be understood. To that end, the 3D brain unit model is an excellent tool, and can be used to build a larger network of 3D brain units, in which the properties for each unit can be defined independently to reflect local differences in characteristics of the brain.
Collapse
Affiliation(s)
- Esmée Vendel
- Mathematical Institute, Leiden University, Leiden, The Netherlands
| | - Vivi Rottschäfer
- Mathematical Institute, Leiden University, Leiden, The Netherlands
- * E-mail: (VR); (EL)
| | - Elizabeth C. M. de Lange
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
- * E-mail: (VR); (EL)
| |
Collapse
|
7
|
Sakita M, Murakami S, Nonaka K, Sakamoto R, Saito T, Isobe W, Kumagai S. Different patterns in age-related morphometric alteration of myelinated fibers and capillaries of the tibial nerve: a longitudinal study in normal rats. J Anat 2020; 236:1101-1111. [PMID: 32052433 DOI: 10.1111/joa.13168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/11/2022] Open
Abstract
Age-related regression of myelinated fibers in peripheral nerves of the lower limbs is strongly influenced by capillaries and results in balance dysfunction and falls. However, the temporal relationships between alteration patterns of myelinated fibers and capillaries have not yet been clarified. This study aimed to investigate age-related morphological and histological changes of both myelinated fibers and capillaries in peripheral nerves to clarify whether myelinated fibers or capillaries change earlier. Seven male Wistar rats each were randomly selected at 20 weeks (young group), 70 weeks (middle group), and 97 weeks (old group) for histological evaluations. The left and right tibial nerves were removed morphologically and histologically to examine myelinated fibers and capillaries. Axon diameter and myelin thickness were almost unaltered in the middle group compared with the young group but were significantly reduced in the old group when compared with the other two groups. However, the capillary diameter and number of microvascular branch points were substantially reduced in the middle group. The current study demonstrates that myelinated fibers of peripheral nerves show signs of regression in elderly rats, whereas capillaries start to reduce in middle-aged animals. In normal aging of the tibial nerve, capillaries may regress before myelinated fibers.
Collapse
Affiliation(s)
- Masahiro Sakita
- Graduate School of Health Sciences, Kyoto Tachibana University, Kyoto, Japan
| | - Shinichiro Murakami
- Department of Physical Therapy, Faculty of Health Care Sciences, Himeji-Dokkyo University, Hyogo, Japan
| | - Koji Nonaka
- Department of Rehabilitation, Faculty of Health Sciences, Naragakuen University, Nara, Japan
| | - Ryuji Sakamoto
- Department of Physical Therapy, Takarazuka University of Medical and Health Care, Hyogo, Japan
| | - Takafumi Saito
- Department of Physical Therapy, Aso Rehabilitation College, Fukuoka, Japan
| | - Wataru Isobe
- Department of Rehabilitation, Mitsubishi Kyoto Hospital, Kyoto, Japan
| | - Shuzo Kumagai
- Laboratory of Health and Exercise Epidemiology, Center for Health Science and Counseling, Kyushu University, Fukuoka, Japan
| |
Collapse
|
8
|
Zheng T, Feng Z, Wang X, Jiang T, Jin R, Zhao P, Luo T, Gong H, Luo Q, Yuan J. Review of micro-optical sectioning tomography (MOST): technology and applications for whole-brain optical imaging [Invited]. BIOMEDICAL OPTICS EXPRESS 2019; 10:4075-4096. [PMID: 31452996 PMCID: PMC6701528 DOI: 10.1364/boe.10.004075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/20/2019] [Accepted: 06/25/2019] [Indexed: 05/14/2023]
Abstract
Elucidating connectivity and functionality at the whole-brain level is one of the most challenging research goals in neuroscience. Various whole-brain optical imaging technologies with submicron lateral resolution have been developed to reveal the fine structures of brain-wide neural and vascular networks at the mesoscopic level. Among them, micro-optical sectioning tomography (MOST) is attracting increasing attention, as a variety of technological variations and solutions tailored toward different biological applications have been optimized. Here, we summarize the recent development of MOST technology in whole-brain imaging and anticipate future improvements.
Collapse
Affiliation(s)
- Ting Zheng
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Equal contribution
| | - Zhao Feng
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Equal contribution
| | - Xiaojun Wang
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tao Jiang
- HUST–Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, Jiangsu 215000, China
| | - Rui Jin
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Peilin Zhao
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Ting Luo
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Hui Gong
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- HUST–Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, Jiangsu 215000, China
| | - Qingming Luo
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- HUST–Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, Jiangsu 215000, China
| | - Jing Yuan
- Collaborative Innovation Center for Biomedical Engineering, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Britton Chance Center and MOE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- HUST–Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, Jiangsu 215000, China
| |
Collapse
|
9
|
Wu D, Zhang J. Evidence of the diffusion time dependence of intravoxel incoherent motion in the brain. Magn Reson Med 2019; 82:2225-2235. [PMID: 31267578 DOI: 10.1002/mrm.27879] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/31/2019] [Accepted: 06/01/2019] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate the diffusion time (TD ) dependence of intravoxel incoherent motion (IVIM) signals in the brain. METHODS A 3-compartment IVIM model was proposed to characterize 2 types of microcirculatory flows in addition to tissue water in the brain: flows that cross multiple vascular segments (pseudo-diffusive) and flows that stay in 1 segment (ballistic) within TD . The model was first evaluated using simulated flow signals. Experimentally, flow-compensated (FC) pulsed-gradient spin-echo (PGSE) and oscillating-gradient spin-echo (OGSE) sequences were tested using a flow phantom and then used to examine IVIM signals in the mouse brain with TD ranging from ~2.5 ms to 40 ms on an 11.7T scanner. RESULTS By fitting the model to simulated flow signals, we demonstrated the TD dependency of the estimated fraction of pseudo-diffusive flow and the pseudo-diffusion coefficient (D*), which were dictated by the characteristic timescale of microcirculatory flow (τ). Flow phantom experiments validated that the OGSE and FC-PGSE sequences were not susceptible to the change in flow velocity. In vivo mouse brain data showed that both the estimated fraction of pseudo-diffusive flow and D* increased significantly as TD increased. CONCLUSION We demonstrated that IVIM signals measured in the brain are TD -dependent, potentially because more microcirculatory flows approach the pseudo-diffusive limit as TD increases with respect to τ. Measuring the TD dependency of IVIM signals may provide additional information on microvascular flows in the brain.
Collapse
Affiliation(s)
- Dan Wu
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Jiangyang Zhang
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| |
Collapse
|
10
|
Vendel E, Rottschäfer V, de Lange ECM. The need for mathematical modelling of spatial drug distribution within the brain. Fluids Barriers CNS 2019; 16:12. [PMID: 31092261 PMCID: PMC6521438 DOI: 10.1186/s12987-019-0133-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/19/2019] [Indexed: 12/17/2022] Open
Abstract
The blood brain barrier (BBB) is the main barrier that separates the blood from the brain. Because of the BBB, the drug concentration-time profile in the brain may be substantially different from that in the blood. Within the brain, the drug is subject to distributional and elimination processes: diffusion, bulk flow of the brain extracellular fluid (ECF), extra-intracellular exchange, bulk flow of the cerebrospinal fluid (CSF), binding and metabolism. Drug effects are driven by the concentration of a drug at the site of its target and by drug-target interactions. Therefore, a quantitative understanding is needed of the distribution of a drug within the brain in order to predict its effect. Mathematical models can help in the understanding of drug distribution within the brain. The aim of this review is to provide a comprehensive overview of system-specific and drug-specific properties that affect the local distribution of drugs in the brain and of currently existing mathematical models that describe local drug distribution within the brain. Furthermore, we provide an overview on which processes have been addressed in these models and which have not. Altogether, we conclude that there is a need for a more comprehensive and integrated model that fills the current gaps in predicting the local drug distribution within the brain.
Collapse
Affiliation(s)
- Esmée Vendel
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA, Leiden, The Netherlands
| | - Vivi Rottschäfer
- Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA, Leiden, The Netherlands
| | - Elizabeth C M de Lange
- Leiden Academic Centre for Drug Research, Einsteinweg 55, 2333CC, Leiden, The Netherlands.
| |
Collapse
|
11
|
Sakita M, Murakami S, Fujino H, Hayashi S, Kameyama K, Saito T, Kumagai S. Remodeling of myelinated fibers and internal capillaries in distal peripheral nerves following aerobic exercise in aged rats. J Appl Physiol (1985) 2018; 125:1051-1061. [DOI: 10.1152/japplphysiol.00257.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to determine whether aerobic exercise (AE) in old age contributes to improving the morphologies of myelinated fibers (MFs) in peripheral nerves as well as capillaries. Furthermore, we investigated whether such processes are associated with complementary activity of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the circulating blood and peripheral nerve tissue. Fourteen male Wistar rats (age: 95 wk) were randomly divided into moderate AE ( n = 8) and sedentary (SED; n = 6) groups. Rats in the AE group performed treadmill running for 1 h per day for 2 wk, following which the bilateral tibial nerves of the two groups were removed to examine MF and capillary structure. Levels of BDNF and VEGF in the serum and peripheral nerves were analyzed via enzyme-linked immunosorbent assay. Myelin thickness, axon diameter, and capillary luminal diameter were significantly larger in the AE group than in the SED group ( P < 0.0001). Levels of serum BDNF and VEGF were significantly lower and higher, respectively, in the AE group than in the SED group ( P < 0.001). Conversely, BDNF and VEGF levels in tibial nerve tissue were significantly higher, respectively, and lower in the AE group than in the SED group ( P < 0.001). In conclusion, our study indicates that regular AE induces enlargement of the capillaries and thickens the myelin in aged peripheral nerves, likely via a complementary process involving BDNF and VEGF. NEW & NOTEWORTHY Accumulating evidence indicates that age-related sarcopenia is accompanied by the degeneration of myelinated fibers (MFs) in peripheral nerves. Our study indicates that regular aerobic exercise contributes to increased thickness of the myelin surrounding MFs and enlargement of the capillaries, likely via a complementary process involving brain-derived neurotrophic factor and vascular endothelial growth factor. Our findings demonstrate that regular, moderate-intensity aerobic exercise may help to prevent and reverse peripheral nerve regression in older adults.
Collapse
Affiliation(s)
- Masahiro Sakita
- Faculty of Health Sciences, Department of Physical Therapy, Kyoto Tachibana University, Kyoto City, Kyoto, Japan
| | - Shinichiro Murakami
- Faculty of Health Care Sciences, Department of Physical Therapy, Himeji-Dokkyo University, Himeji City, Hyogo, Japan
| | - Hidemi Fujino
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe City, Hyogo, Japan
| | - Satoshi Hayashi
- Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama City, Okayama, Japan
| | - Kazuyoshi Kameyama
- Department of Occupational Therapy, Hakuhokai Medical Technical School Ako, Ako City, Hyogo, Japan
| | - Takafumi Saito
- Department of Physical Therapy, Aso Rehabilitation College, Hakata Ward, Fukuoka, Japan
| | - Shuzo Kumagai
- Laboratory of Health and Exercise Epidemiology, Center for Health Science and Counseling, Kyushu University, Kasuga City, Fukuoka, Japan
| |
Collapse
|
12
|
Improving the Prediction of Local Drug Distribution Profiles in the Brain with a New 2D Mathematical Model. Bull Math Biol 2018; 81:3477-3507. [PMID: 30091104 PMCID: PMC6722198 DOI: 10.1007/s11538-018-0469-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 07/13/2018] [Indexed: 12/17/2022]
Abstract
The development of drugs that target the brain is very challenging. A quantitative understanding is needed of the complex processes that govern the concentration–time profile of a drug (pharmacokinetics) within the brain. So far, there are no studies on predicting the drug concentration within the brain that focus not only on the transport of drugs to the brain through the blood–brain barrier (BBB), but also on drug transport and binding within the brain. Here, we develop a new model for a 2D square brain tissue unit, consisting of brain extracellular fluid (ECF) that is surrounded by the brain capillaries. We describe the change in free drug concentration within the brain ECF, by a partial differential equation (PDE). To include drug binding, we couple this PDE to two ordinary differential equations that describe the concentration–time profile of drug bound to specific as well as non-specific binding sites that we assume to be evenly distributed over the brain ECF. The model boundary conditions reflect how free drug enters and leaves the brain ECF by passing the BBB, located at the level of the brain capillaries. We study the influence of parameter values for BBB permeability, brain ECF bulk flow, drug diffusion through the brain ECF and drug binding kinetics, on the concentration–time profiles of free and bound drug.
Collapse
|
13
|
Cheng P, Li D, Gao Y, Cao T, Jiang H, Wang J, Li J, Zhang S, Song Y, Liu B, Wang C, Yang L, Pei G. Prevascularization promotes endogenous cell-mediated angiogenesis by upregulating the expression of fibrinogen and connective tissue growth factor in tissue-engineered bone grafts. Stem Cell Res Ther 2018; 9:176. [PMID: 29973254 PMCID: PMC6030739 DOI: 10.1186/s13287-018-0925-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/29/2018] [Accepted: 06/13/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Vascularization is one of the most important processes in tissue-engineered bone graft (TEBG)-mediated regeneration of large segmental bone defects. We previously showed that prevascularization of TEBGs promoted capillary vessel formation within the defected site and accelerated new bone formation. However, the precise mechanisms and contribution of endogenous cells were not explored. METHODS We established a large defect (5 mm) model in the femur of EGFP+ transgenic rats and implanted a β-tricalcium phosphate (β-TCP) scaffold seeded with exogenous EGFP- cells; the femoral vascular bundle was inserted into the scaffold before implantation in the prevascularized TEBG group. Histopathology and scanning electron microscopy were performed and connective tissue growth factor (CTGF) and fibrin expression, exogenous cell survival, endogenous cell migration and behavior, and collagen type I and III deposition were assessed at 1 and 4 weeks post implantation. RESULTS We found that the fibrinogen content can be increased at the early stage of vascular bundle transplantation, forming a fibrin reticulate structure and tubular connections between pores of β-TCP material, which provides a support for cell attachment and migration. Meanwhile, CTGF expression is increased, and more endogenous cells can be recruited and promote collagen synthesis and angiogenesis. By 4 weeks post implantation, the tubular connections transformed into von Willebrand factor-positive capillary-like structures with deposition of type III collagen, and accelerated angiogenesis of endogenous cells. CONCLUSIONS These findings demonstrate that prevascularization promotes the recruitment of endogenous cells and collagen deposition by upregulating fibrinogen and CTGF, directly resulting in new blood vessel formation. In addition, this molecular mechanism can be used to establish fast-acting angiogenesis materials in future clinical applications.
Collapse
Affiliation(s)
- Pengzhen Cheng
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Donglin Li
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China.,Hospital 463 of People's Liberation Army, Shenyang, 110042, People's Republic of China
| | - Yi Gao
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Tianqing Cao
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Huijie Jiang
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Jimeng Wang
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China.,Department of Orthopedics, The 251st Hospital of PLA, Zhangjiakou, 075000, China
| | - Junqin Li
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Shuaishuai Zhang
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Yue Song
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Bin Liu
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Chunmei Wang
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China
| | - Liu Yang
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China.
| | - Guoxian Pei
- Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, People's Republic of China.
| |
Collapse
|
14
|
He X, Wengler K, Schweitzer ME. Diffusion sensitivity of 3D-GRASE in arterial spin labeling perfusion. Magn Reson Med 2018; 80:736-747. [DOI: 10.1002/mrm.27058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/02/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Xiang He
- Department of Radiology; Stony Brook University; Stony Brook New York USA
| | - Kenneth Wengler
- Department of Biomedical Engineering; Stony Brook University; Stony Brook New York USA
| | - Mark E. Schweitzer
- Department of Radiology; Stony Brook University; Stony Brook New York USA
| |
Collapse
|
15
|
3D morphological analysis of the mouse cerebral vasculature: Comparison of in vivo and ex vivo methods. PLoS One 2017; 12:e0186676. [PMID: 29053753 PMCID: PMC5650181 DOI: 10.1371/journal.pone.0186676] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 10/05/2017] [Indexed: 02/06/2023] Open
Abstract
Ex vivo 2-photon fluorescence microscopy (2PFM) with optical clearing enables vascular imaging deep into tissue. However, optical clearing may also produce spherical aberrations if the objective lens is not index-matched to the clearing material, while the perfusion, clearing, and fixation procedure may alter vascular morphology. We compared in vivo and ex vivo 2PFM in mice, focusing on apparent differences in microvascular signal and morphology. Following in vivo imaging, the mice (four total) were perfused with a fluorescent gel and their brains fructose-cleared. The brain regions imaged in vivo were imaged ex vivo. Vessels were segmented in both images using an automated tracing algorithm that accounts for the spatially varying PSF in the ex vivo images. This spatial variance is induced by spherical aberrations caused by imaging fructose-cleared tissue with a water-immersion objective. Alignment of the ex vivo image to the in vivo image through a non-linear warping algorithm enabled comparison of apparent vessel diameter, as well as differences in signal. Shrinkage varied as a function of diameter, with capillaries rendered smaller ex vivo by 13%, while penetrating vessels shrunk by 34%. The pial vasculature attenuated in vivo microvascular signal by 40% 300 μm below the tissue surface, but this effect was absent ex vivo. On the whole, ex vivo imaging was found to be valuable for studying deep cortical vasculature.
Collapse
|
16
|
Firsova AB, Bird AD, Abebe D, Ng J, Mollard R, Cole TJ. Fresh Noncultured Endothelial Progenitor Cells Improve Neonatal Lung Hyperoxia-Induced Alveolar Injury. Stem Cells Transl Med 2017; 6:2094-2105. [PMID: 29027762 PMCID: PMC5702522 DOI: 10.1002/sctm.17-0093] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/05/2017] [Indexed: 01/01/2023] Open
Abstract
Treatment of preterm human infants with high oxygen can result in disrupted lung alveolar and vascular development. Local or systemic administration of endothelial progenitor cells (EPCs) is reported to remedy such disruption in animal models. In this study, the effects of both fresh (enriched for KDR) and cultured bone marrow (BM)-derived cell populations with EPC characteristics were examined following hyperoxia in neonatal mouse lungs. Intraperitoneal injection of fresh EPCs into five-day-old mice treated with 90% oxygen resulted in full recovery of hyperoxia-induced alveolar disruption by 56 days of age. Partial recovery in septal number following hyperoxia was observed following injection of short-term cultured EPCs, yet aberrant tissue growths appeared following injection of long-term cultured cells. Fresh and long-term cultured cells had no impact on blood vessel development. Short-term cultured cells increased blood vessel number in normoxic and hyperoxic mice by 28 days but had no impact on day 56. Injection of fresh EPCs into normoxic mice significantly reduced alveolarization compared with phosphate buffered saline-injected normoxic controls. These results indicate that fresh BM EPCs have a higher and safer corrective profile in a hyperoxia-induced lung injury model compared with cultured BM EPCs but may be detrimental to the normoxic lung. The appearance of aberrant tissue growths and other side effects following injection of cultured EPCs warrants further investigation. Stem Cells Translational Medicine 2017;6:2094-2105.
Collapse
Affiliation(s)
- Alexandra B Firsova
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - A Daniel Bird
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Degu Abebe
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Judy Ng
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Richard Mollard
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.,Department of Veterinary and Agricultural Science, University of Melbourne, Parkville, Victoria, Australia
| | - Timothy J Cole
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
17
|
Aum DJ, Vellimana AK, Singh I, Milner E, Nelson JW, Han BH, Zipfel GJ. A novel fluorescent imaging technique for assessment of cerebral vasospasm after experimental subarachnoid hemorrhage. Sci Rep 2017; 7:9126. [PMID: 28831103 PMCID: PMC5567362 DOI: 10.1038/s41598-017-09070-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/21/2017] [Indexed: 12/22/2022] Open
Abstract
Various techniques have been developed to study changes in the cerebral vasculature in numerous neuropathological processes including subarachnoid hemorrhage (SAH). One of the most widely employed techniques uses India ink-gelatin casting, which presents numerous challenges due to its high viscosity, rapid solidification, and its impact on immunohistochemical analysis. To overcome these limitations, we developed a novel technique for assessing cerebral vasospasm using cerebrovascular perfusion with ROX, SE (5-Carboxy-X-Rhodamine, Succinimidyl Ester), a fluorescent labeling dye. We found that ROX SE perfusion achieves excellent delineation of the cerebral vasculature, was qualitatively and quantitatively superior to India ink-gelatin casting for the assessment of cerebral vasospasm, permits outstanding immunohistochemical examination of non-vasospasm components of secondary brain injury, and is a more efficient and cost-effective experimental technique. ROX SE perfusion is therefore a novel and highly useful technique for studying cerebrovascular pathology following experimental SAH.
Collapse
Affiliation(s)
- Diane J Aum
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Ananth K Vellimana
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Itender Singh
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Eric Milner
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - James W Nelson
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Byung Hee Han
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA.,Department of Pharmacology, A.T. Still University of Health Sciences, Kirksville, MO, USA
| | - Gregory J Zipfel
- Department of Neurological Surgery, Washington University School of Medicine, St Louis, MO, USA. .,Department of Neurology, Washington University School of Medicine, St Louis, MO, USA.
| |
Collapse
|
18
|
Montoro R, Dickie R. Comparison of tissue processing methods for microvascular visualization in axolotls. MethodsX 2017; 4:265-273. [PMID: 28913170 PMCID: PMC5587881 DOI: 10.1016/j.mex.2017.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/16/2017] [Indexed: 11/18/2022] Open
Abstract
The vascular system, the pipeline for oxygen and nutrient delivery to tissues, is essential for vertebrate development, growth, injury repair, and regeneration. With their capacity to regenerate entire appendages throughout their lifespan, axolotls are an unparalleled model for vertebrate regeneration, but they lack many of the molecular tools that facilitate vascular imaging in other animal models. The determination of vascular metrics requires high quality image data for the discrimination of vessels from background tissue. Quantification of the vasculature using perfused, cleared specimens is well-established in mammalian systems, but has not been widely employed in amphibians. The objective of this study was to optimize tissue preparation methods for the visualization of the microvascular network in axolotls, providing a basis for the quantification of regenerative angiogenesis. To accomplish this aim, we performed intracardiac perfusion of pigment-based contrast agents and evaluated aqueous and non-aqueous clearing techniques. The methods were verified by comparing the quality of the vascular images and the observable vascular density across treatment groups. Simple and inexpensive, these tissue processing techniques will be of use in studies assessing vascular growth and remodeling within the context of regeneration. Advantages of this method include: Higher contrast of the vasculature within the 3D context of the surrounding tissue
Enhanced detection of microvasculature facilitating vascular quantification
Compatibility with other labeling techniques
Collapse
|
19
|
Yuan K, Orcholski ME, Huang NF, de Jesus Perez VA. In Vivo Study of Human Endothelial-Pericyte Interaction Using the Matrix Gel Plug Assay in Mouse. J Vis Exp 2016. [PMID: 28060266 DOI: 10.3791/54617] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Angiogenesis is the process by which new blood vessels are formed from existing vessels. New vessel growth requires coordinated endothelial cell proliferation, migration, and alignment to form tubular structures followed by recruitment of pericytes to provide mural support and facilitate vessel maturation. Current in vitro cell culture approaches cannot fully reproduce the complex biological environment where endothelial cells and pericytes interact to produce functional vessels. We present a novel application of the in vivo matrix gel plug assay to study endothelial-pericyte interactions and formation of functional blood vessels using severe combined immune deficiency mutation (SCID) mice. Briefly, matrix gel is mixed with a solution containing endothelial cells with or without pericytes followed by injection into the back of anesthetized SCID mice. After 14 days, the matrix gel plugs are removed, fixed and sectioned for histological analysis. The length, number, size and extent of pericyte coverage of mature vessels (defined by the presence of red blood cells in the lumen) can be quantified and compared between experimental groups using commercial statistical platforms. Beyond its use as an angiogenesis assay, this matrix gel plug assay can be used to conduct genetic studies and as a platform for drug discovery. In conclusion, this protocol will allow researchers to complement available in vitro assays for the study of endothelial-pericyte interactions and their relevance to either systemic or pulmonary angiogenesis.
Collapse
Affiliation(s)
- Ke Yuan
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Stanford University; Stanford Cardiovascular Institute, School of Medicine, Stanford University
| | - Mark E Orcholski
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Stanford University; Stanford Cardiovascular Institute, School of Medicine, Stanford University
| | - Ngan F Huang
- Stanford Cardiovascular Institute, School of Medicine, Stanford University; VA Palo Alto Health Care System, Department of Cardiothoracic Surgery, School of Medicine, Stanford University
| | - Vinicio A de Jesus Perez
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Stanford University; Stanford Cardiovascular Institute, School of Medicine, Stanford University;
| |
Collapse
|
20
|
Nowak MR, Lozovskiy A, Dobroskok D. Knife-edge scanning microscopy for in silico study of cerebral blood flow: From biological imaging data to flow simulations. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:5957-5960. [PMID: 28269609 DOI: 10.1109/embc.2016.7592085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Knife-edge scanning microscopy provides the capability to image whole-brain cerebral microvasculature of small organisms, such as mice, at sub-micron resolution, providing a feasible foundation for the reconstruction of circulatory pathways from the systemic to cellular scale. In this paper, we illustrate the feasibility of using this data to model cerebral blood flow using numerical simulations. Starting with a small vascular element in microcirculation of interest, we present its segmentation from the imaging-data volume, construction of its triangular surface mesh, assembly of its tetrahedral volumetric mesh from the surface, and then conclude with Stokes flow simulation of plasma through the microvascular vessel.
Collapse
|
21
|
Sakita M, Murakami S, Fujino H. Age-related morphological regression of myelinated fibers and capillary architecture of distal peripheral nerves in rats. BMC Neurosci 2016; 17:39. [PMID: 27342571 PMCID: PMC4919893 DOI: 10.1186/s12868-016-0277-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 06/16/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Regression of myelinated peripheral nerve fibers in the lower extremities contributes to sarcopenia and balance dysfunction in normal aging. This subclinical regression of myelinated fibers (MFs) is heavily influenced by alterations in microvasculature, though the mechanism underlying these age-related degenerative phenomena remains unclear. The aim of the present study was to examine age-related regressions in myelinated distal peripheral nerve fibers as well as capillary architecture in rats using both morphological and histochemical methods. RESULTS MFs were categorized into tertiles of 'large', 'medium', and 'small' sizes based on the distribution of MF diameters. A two-way ANOVA was used to assess effects of fiber size (large/medium/small) and group (young/elderly) on myelin thickness, axon diameter, myelin perimeter, axon perimeter, and G-ratio (axon diameter/fiber diameter). Significant main effects were observed for both MF size and group with respect to all dimensions except for G-ratio. Values for fiber diameter (P < 0.01), myelin thickness (P < 0.01), axon diameter (P < 0.01), myelin perimeter (P < 0.01), and axon perimeter (P < 0.01) were significantly lower than those in the young group. Additionally, mean capillary diameter and number of microvascular branch points were significantly lower in the elderly group than in the young group. CONCLUSIONS The present study demonstrated that spontaneous age-related regression predominantly occurs for all fiber sizes in the distal peripheral nerves and the capillary architecture. The results of the present study further suggest that both the distal MFs and capillaries in the peripheral nerve may simultaneously regress with aging.
Collapse
Affiliation(s)
- Masahiro Sakita
- Department of Physical Therapy, Faculty of Health Sciences, Kyoto Tachibana University, 34 Oyakeyamada, Yamashina Ward, Kyoto City, Kyoto, 607-8175, Japan.
| | - Shinichiro Murakami
- Department of Physical Therapy, Faculty of Health Care Sciences, Himeji-Dokkyo University, 7-2-1 Kamiono, Himeji City, Hyogo, 670-0896, Japan
| | - Hidemi Fujino
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma Ward, Kobe City, Hyogo, 654-0412, Japan
| |
Collapse
|
22
|
Kolinko Y, Cendelin J, Kralickova M, Tonar Z. Smaller Absolute Quantities but Greater Relative Densities of Microvessels Are Associated with Cerebellar Degeneration in Lurcher Mice. Front Neuroanat 2016; 10:35. [PMID: 27147979 PMCID: PMC4835681 DOI: 10.3389/fnana.2016.00035] [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: 11/11/2015] [Accepted: 03/15/2016] [Indexed: 11/17/2022] Open
Abstract
Degenerative affections of nerve tissues are often accompanied by changes of vascularization. In this regard, not much is known about hereditary cerebellar degeneration. In this study, we compared the vascularity of the individual cerebellar components and the mesencephalon of 3-month-old wild type mice (n = 5) and Lurcher mutant mice, which represent a model of hereditary olivocerebellar degeneration (n = 5). Paraformaldehyde-fixed brains were processed into 18-μm thick serial sections with random orientation. Microvessels were visualized using polyclonal rabbit anti-laminin antibodies. Then, the stacks comprised of three 5-μm thick optical sections were recorded using systematic uniform random sampling. Stereological assessment was conducted based on photo-documentation. We found that each of the cerebellar components has its own features of vascularity. The greatest number and length of vessels were found in the granular layer; the number of vessels was lower in the molecular layer, and the lowest number of vessels was observed in the cerebellar nuclei corresponding with their low volume. Nevertheless, the nuclei had the greatest density of blood vessels. The reduction of cerebellum volume in the Lurcher mice was accompanied by a reduction in vascularization in the individual cerebellar components, mainly in the cortex. Moreover, despite the lower density of microvessels in the Lurcher mice compared with the wild type mice, the relative density of microvessels in the cerebellar cortex and nuclei was greater in Lurcher mice. The complete primary morphometric data, in the form of continuous variables, is included as a supplement. Mapping of the cerebellar and midbrain microvessels has explanatory potential for studies using mouse models of neurodegeneration.
Collapse
Affiliation(s)
- Yaroslav Kolinko
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| | - Jan Cendelin
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| | - Milena Kralickova
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| | - Zbynek Tonar
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University in Prague Pilsen, Czech Republic
| |
Collapse
|
23
|
Pienaar IS, Lee CH, Elson JL, McGuinness L, Gentleman SM, Kalaria RN, Dexter DT. Deep-brain stimulation associates with improved microvascular integrity in the subthalamic nucleus in Parkinson's disease. Neurobiol Dis 2014; 74:392-405. [PMID: 25533682 DOI: 10.1016/j.nbd.2014.12.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/01/2014] [Accepted: 12/05/2014] [Indexed: 12/25/2022] Open
Abstract
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become an accepted treatment for motor symptoms in a subset of Parkinson's disease (PD) patients. The mechanisms why DBS is effective are incompletely understood, but previous studies show that DBS targeted in brain structures other than the STN may modify the microvasculature. However, this has not been studied in PD subjects who have received STN-DBS. Here we investigated the extent and nature of microvascular changes in post-mortem STN samples from STN-DBS PD patients, compared to aged controls and PD patients who had not been treated with STN-DBS. We used immunohistochemical and immunofluorescent methods to assess serial STN-containing brain sections from PD and STN-DBS PD cases, compared to similar age controls using specific antibodies to detect capillaries, an adherens junction and tight junction-associated proteins as well as activated microglia. Cellular features in stained sections were quantified by confocal fluorescence microscopy and stereological methods in conjunction with in vitro imaging tools. We found significant upregulation of microvessel endothelial cell thickness, length and density but lowered activated microglia density and striking upregulation of all analysed adherens junction and tight junction-associated proteins in STN-DBS PD patients compared to non-DBS PD patients and controls. Moreover, in STN-DBS PD samples, expression of an angiogenic factor, vascular endothelial growth factor (VEGF), was significantly upregulated compared to the other groups. Our findings suggest that overexpressed VEGF and downregulation of inflammatory processes may be critical mechanisms underlying the DBS-induced microvascular changes.
Collapse
Affiliation(s)
- Ilse S Pienaar
- Centre for Neuroinflammation & Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, United Kingdom.
| | - Cecilia Heyne Lee
- The Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Joanna L Elson
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne NE1 3BZ, United Kingdom; Centre for Human Metabonomics, North-West University, Potchefstroom, South Africa
| | - Louisa McGuinness
- Centre for Neuroinflammation & Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, United Kingdom
| | - Stephen M Gentleman
- Centre for Neuroinflammation & Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, United Kingdom
| | - Raj N Kalaria
- Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, United Kingdom
| | - David T Dexter
- Centre for Neuroinflammation & Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, United Kingdom
| |
Collapse
|
24
|
Chong MSK, Lim J, Goh J, Sia MW, Chan JKY, Teoh SH. Cocultures of Mesenchymal Stem Cells and Endothelial Cells As Organotypic Models of Prostate Cancer Metastasis. Mol Pharm 2014; 11:2126-33. [DOI: 10.1021/mp500141b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Mark S. K. Chong
- Division
of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Jing Lim
- Division
of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Junwei Goh
- Bioengineering Laboratory, Technology Centre
for Life Sciences, Singapore Polytechnic, Singapore 139651
| | - Ming W. Sia
- Division
of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| | - Jerry K. Y. Chan
- Department of Obstetrics
and Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077
- Department
of Reproductive Medicine, KK Women’s and Children’s Hospital, Singapore 229899
- Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School, Singapore 169857
| | - Swee H. Teoh
- Division
of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457
| |
Collapse
|
25
|
Xue S, Gong H, Jiang T, Luo W, Meng Y, Liu Q, Chen S, Li A. Indian-ink perfusion based method for reconstructing continuous vascular networks in whole mouse brain. PLoS One 2014; 9:e88067. [PMID: 24498247 PMCID: PMC3907580 DOI: 10.1371/journal.pone.0088067] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 01/05/2014] [Indexed: 11/18/2022] Open
Abstract
The topology of the cerebral vasculature, which is the energy transport corridor of the brain, can be used to study cerebral circulatory pathways. Limited by the restrictions of the vascular markers and imaging methods, studies on cerebral vascular structure now mainly focus on either observation of the macro vessels in a whole brain or imaging of the micro vessels in a small region. Simultaneous vascular studies of arteries, veins and capillaries have not been achieved in the whole brain of mammals. Here, we have combined the improved gelatin-Indian ink vessel perfusion process with Micro-Optical Sectioning Tomography for imaging the vessel network of an entire mouse brain. With 17 days of work, an integral dataset for the entire cerebral vessels was acquired. The voxel resolution is 0.35×0.4×2.0 µm(3) for the whole brain. Besides the observations of fine and complex vascular networks in the reconstructed slices and entire brain views, a representative continuous vascular tracking has been demonstrated in the deep thalamus. This study provided an effective method for studying the entire macro and micro vascular networks of mouse brain simultaneously.
Collapse
Affiliation(s)
- Songchao Xue
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Tao Jiang
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Weihua Luo
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Yuanzheng Meng
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Qian Liu
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbin Chen
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Anan Li
- Britton Chance Center for Biomedical Photonics, Huazhong University of Science and Technology-Wuhan National Laboratory for Optoelectronics, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- * E-mail:
| |
Collapse
|
26
|
A computational model of oxygen transport in the cerebrocapillary levels for normal and pathologic brain function. J Cereb Blood Flow Metab 2013; 33:1633-41. [PMID: 23921901 PMCID: PMC3790934 DOI: 10.1038/jcbfm.2013.119] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 05/23/2013] [Accepted: 06/17/2013] [Indexed: 01/03/2023]
Abstract
The oxygen exchange and correlation between the cerebral blood flow (CBF) and cerebral metabolic rate of oxygen consumption (CMRO2) in the cortical capillary levels for normal and pathologic brain functions remain the subject of debate. A 3D realistic mesoscale model of the cortical capillary network (non-tree like) is constructed using a random Voronoi tessellation in which each edge represents a capillary segment. The hemodynamics and oxygen transport are numerically simulated in the model, which involves rheological laws in the capillaries, oxygen diffusion, and non-linear binding of oxygen to hemoglobin, respectively. The findings show that the cerebral hypoxia due to a significant decreased perfusion (as can occur in stroke) can be avoided by a moderate reduction in oxygen demand. Oxygen extraction fraction (OEF) can be an important indicator for the brain oxygen metabolism under normal perfusion and misery-perfusion syndrome (leading to ischemia). The results demonstrated that a disproportionately large increase in blood supply is required for a small increase in the oxygen demand, which, in turn, is strongly dependent on the resting OEF. The predicted flow-metabolism coupling in the model supports the experimental studies of spatiotemporal stimulations in humans by positron emission tomography and functional magnetic resonance imaging.
Collapse
|
27
|
Zhu H, Zou L, Tian J, Du G, Gao Y. SMND-309, a novel derivative of salvianolic acid B, protects rat brains ischemia and reperfusion injury by targeting the JAK2/STAT3 pathway. Eur J Pharmacol 2013; 714:23-31. [PMID: 23764464 DOI: 10.1016/j.ejphar.2013.05.043] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/28/2013] [Accepted: 05/30/2013] [Indexed: 01/19/2023]
Abstract
SMND-309 is a novel derivative of salvianolic acid B, and has shown protective effects against rat cortical neuron damage in vitro and in vivo. However the molecular mechanisms through which SMND-309 affords this protection are unclear. The present study aimed to investigate the mechanisms associated with the protective activities of SMND-309 in a cerebral ischemia and reperfusion injury rat model. In this study, we used AG490, a specific inhibitor of the signaling pathway involving the Janus Kinase 2 (JAK2)/Signal Transducers and Activators of Transcription 3 (STAT3) signaling molecules and suramin, a potent inhibitor of vascular endothelial growth factor (VEGF), to investigate the mechanisms of SMND-309. The cerebral ischemia and reperfusion injury model was induced by performing middle cerebral artery occlusion (MCAO) in the rats. SMND-309 mitigated the effects of ischemia and reperfusion injury on brain by decreasing the infract volume, improving neurological function, increasing the survival of neurons and promoting angiogenesis by increasing the levels of erythropoietin (EPO), erythropoietin receptor (EPOR), phosphorylated JAK2 (P-JAK2), phosphorylated STAT3 (P-STAT3), VEGF and VEGF receptor 2 (Flk-1) in the brain. Our results suggest that SMND-309 provides significant neuroprotective effects against cerebral ischemia and reperfusion injury. The mechanisms of this protection may be attributed to the increased VEGF expression occurring from the JAK2/STAT3 pathway, activated by the increased EPO/EPOR expression in the brain.
Collapse
Affiliation(s)
- Haibo Zhu
- Department of Pharmacology, Shenyang Pharmaceutical University, 103 Wenhua Road, 110016 Shenyang, PR China
| | | | | | | | | |
Collapse
|
28
|
Huchzermeyer C, Berndt N, Holzhütter HG, Kann O. Oxygen consumption rates during three different neuronal activity states in the hippocampal CA3 network. J Cereb Blood Flow Metab 2013; 33:263-71. [PMID: 23168532 PMCID: PMC3564197 DOI: 10.1038/jcbfm.2012.165] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 09/05/2012] [Accepted: 10/15/2012] [Indexed: 01/09/2023]
Abstract
The brain is an organ with high metabolic rate. However, little is known about energy utilization during different activity states of neuronal networks. We addressed this issue in area CA3 of hippocampal slice cultures under well-defined recording conditions using a 20% O(2) gas mixture. We combined recordings of local field potential and interstitial partial oxygen pressure (pO(2)) during three different activity states, namely fast network oscillations in the gamma-frequency band (30 to 100 Hz), spontaneous network activity and absence of spiking (action potentials). Oxygen consumption rates were determined by pO(2) depth profiles with high spatial resolution and a mathematical model that considers convective transport, diffusion, and activity-dependent consumption of oxygen. We show that: (1) Relative oxygen consumption rate during cholinergic gamma oscillations was 2.2-fold and 5.3-fold higher compared with spontaneous activity and absence of spiking, respectively. (2) Gamma oscillations were associated with a similar large decrease in pO(2) as observed previously with a 95% O(2) gas mixture. (3) Sufficient oxygenation during fast network oscillations in vivo is ensured by the calculated critical radius of 30 to 40 μm around a capillary. We conclude that the structural and biophysical features of brain tissue permit variations in local oxygen consumption by a factor of about five.
Collapse
Affiliation(s)
| | - Nikolaus Berndt
- Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| |
Collapse
|
29
|
Inner capillary diameter of hypothalamic paraventricular nucleus of female rat increases during lactation. BMC Neurosci 2013; 14:7. [PMID: 23302443 PMCID: PMC3548690 DOI: 10.1186/1471-2202-14-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 01/08/2013] [Indexed: 12/31/2022] Open
Abstract
Background The role of the endothelial cell (EC) in blood flow regulation within the central nervous system has been little studied. Here, we explored EC participation in morphological changes of the anterior hypothalamic paraventricular nucleus (PVN) microvasculature of female rats at two reproductive stages with different metabolic demand (virginity and lactation). We measured the inner capillary diameter (ICD) of 800 capillaries from either the magnocellular or parvocellular regions. The space occupied by neural (somas, dendrites and axons) and glial, but excluding vascular elements of the neurovascular compartment was also measured in 100-μm2 sample fields of both PVN subdivisions. Results The PVN of both groups of animals showed ICDs that ranged from 3 to 10 microns. The virgin group presented mostly capillaries with small ICD, whereas the lactating females exhibited a significant increment in the percentage of capillaries with larger ICD. The space occupied by the neural and glial elements of the neurovascular compartment did not show changes with lactation. Conclusions Our findings suggest that during lactation the microvasculature of the PVN of female rats undergoes dynamic, transitory changes in blood flow as represented by an increment in the ICD through a self-cytoplasmic volume modification reflected by EC changes. A model of this process is proposed.
Collapse
|
30
|
Baloyannis SJ, Baloyannis IS. The vascular factor in Alzheimer's disease: a study in Golgi technique and electron microscopy. J Neurol Sci 2012; 322:117-21. [PMID: 22857991 DOI: 10.1016/j.jns.2012.07.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 06/19/2012] [Accepted: 07/05/2012] [Indexed: 12/31/2022]
Abstract
Although the etiopathological background of Alzheimer's disease (AD) is mostly associated with the deposition of Αβ-peptide, the hyperphosphorylation of τ protein, the synaptic pathology and the mitochondrial alterations, the vascular factor may play substantial role in plotting the multifactorial pattern of the disease. We attempted to study the blood capillaries in the hippocampus, the acoustic, the visual and the parietal cortex in twelve early cases of Alzheimer's disease. Samples were processed for Golgi silver impregnation technique and electron microscopy. The morphological findings were compared with normal controls. The study of the brain capillaries in cases of AD, revealed numerous fusiform dilatations, tortuosities, abnormal branching and fusion, though the morphometric estimation revealed a decrease of the number of capillaries per mm(3) in comparison with normal control brains. The ultrastructural study revealed mitochondrial abnormalities in the endothelial cells of a substantial number of capillaries and marked degeneration of the pericytes. Perivascular microglial proliferation was also prominent in the hippocampus and the parietal lobe. Our findings both in Golgi staining and electron microscopy plead in favor of the essential role that the microvascular alterations may play in the broad pathogenetic spectrum of AD.
Collapse
|
31
|
Hippocampal neurovascular and hypothalamic–pituitary–adrenal axis alterations in spontaneously type 2 diabetic GK rats. Exp Neurol 2010; 222:125-34. [DOI: 10.1016/j.expneurol.2009.12.022] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 12/01/2009] [Accepted: 12/22/2009] [Indexed: 01/19/2023]
|
32
|
Jianbin T, Liang H, Jufang H, Hui W, Dan C, Leping Z, Jin Z, Xuegang L. Improved method of ink-gelatin perfusion for visualising rat retinal microvessels. Acta Histochem Cytochem 2008; 41:127-33. [PMID: 18989466 PMCID: PMC2576503 DOI: 10.1267/ahc.08015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 07/17/2008] [Indexed: 12/02/2022] Open
Abstract
To visualize completely rat retinal microvessels, the gelatin-ink perfusion condition was systematically optimized using von Willebrand factor (vWf) immunostaining as control. Whether the vessel showed by the new perfusion condition can be used for double label with neurons or glial cells in the same retina was also tested. Our results showed that infusing rats first with 20 ml of 37°C ink plus 3% gelatin at 140% rat mean arterial pressure (MAP), and subsequently with 20 ml of 37°C ink plus 5% gelatin at 180% rat MAP allowed the ink to completely fill the rat retinal microvessels. Rat retinal microvessels labeled by the perfusion method were more in number than that by vWf immunostaining. Moreover, our data, for the first time, displayed that the improved gelatin-ink perfusion had no effect on and caused no contamination to the following fluorogold labeling or immunostaining of retinal neurons or glial cells in the same tissue. These data suggest that the improved gelatin-ink perfusion technique is a superior method for morphological characterization of rat retinal microvessels, compatible to the double labeling of glial cells and neurons, and it extends the practical scale of the classic method.
Collapse
Affiliation(s)
- Tong Jianbin
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Huang Liang
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Huang Jufang
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Wang Hui
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Chen Dan
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Zeng Leping
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Zhou Jin
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| | - Luo Xuegang
- Department of Anatomy & Neurobiology, Xiangya School of Medicine, Central South University
| |
Collapse
|
33
|
Laferrière A, Millecamps M, Xanthos DN, Xiao WH, Siau C, de Mos M, Sachot C, Ragavendran JV, Huygen FJ, Bennett GJ, Coderre TJ. Cutaneous tactile allodynia associated with microvascular dysfunction in muscle. Mol Pain 2008; 4:49. [PMID: 18957097 PMCID: PMC2584041 DOI: 10.1186/1744-8069-4-49] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Accepted: 10/28/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cutaneous tactile allodynia, or painful hypersensitivity to mechanical stimulation of the skin, is typically associated with neuropathic pain, although also present in chronic pain patients who do not have evidence of nerve injury. We examine whether deep tissue microvascular dysfunction, a feature common in chronic non-neuropathic pain, contributes to allodynia. RESULTS Persistent cutaneous allodynia is produced in rats following a hind paw ischemia-reperfusion injury that induces microvascular dysfunction, including arterial vasospasms and capillary slow flow/no-reflow, in muscle. Microvascular dysfunction leads to persistent muscle ischemia, a reduction of intraepidermal nerve fibers, and allodynia correlated with muscle ischemia, but not with skin nerve loss. The affected hind paw muscle shows lipid peroxidation, an upregulation of nuclear factor kappa B, and enhanced pro-inflammatory cytokines, while allodynia is relieved by agents that inhibit these alterations. Allodynia is increased, along with hind paw muscle lactate, when these rats exercise, and is reduced by an acid sensing ion channel antagonist. CONCLUSION Our results demonstrate how microvascular dysfunction and ischemia in muscle can play a critical role in the development of cutaneous allodynia, and encourage the study of how these mechanisms contribute to chronic pain. We anticipate that focus on the pain mechanisms associated with microvascular dysfunction in muscle will provide new effective treatments for chronic pain patients with cutaneous tactile allodynia.
Collapse
Affiliation(s)
- Andre Laferrière
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Vykhodtseva N, McDannold N, Hynynen K. Progress and problems in the application of focused ultrasound for blood-brain barrier disruption. ULTRASONICS 2008; 48:279-96. [PMID: 18511095 PMCID: PMC2569868 DOI: 10.1016/j.ultras.2008.04.004] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 03/25/2008] [Accepted: 04/06/2008] [Indexed: 05/03/2023]
Abstract
Advances in neuroscience have resulted in the development of new diagnostic and therapeutic agents for potential use in the central nervous system (CNS). However, the ability to deliver the majority of these agents to the brain is limited by the blood-brain barrier (BBB), a specialized structure of the blood vessel wall that hampers transport and diffusion from the blood to the brain. Many CNS disorders could be treated with drugs, enzymes, genes, or large-molecule biotechnological products such as recombinant proteins, if they could cross the BBB. This article reviews the problems of the BBB presence in treating the vast majority of CNS diseases and the efforts to circumvent the BBB through the design of new drugs and the development of more sophisticated delivery methods. Recent advances in the development of noninvasive, targeted drug delivery by MRI-guided ultrasound-induced BBB disruption are also summarized.
Collapse
Affiliation(s)
- Natalia Vykhodtseva
- Department of Radiology, Focused Ultrasound Laboratory, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Room 515, 75 Francis Street, Boston, MA 02115, USA.
| | | | | |
Collapse
|
35
|
Gamma oscillations and spontaneous network activity in the hippocampus are highly sensitive to decreases in pO2 and concomitant changes in mitochondrial redox state. J Neurosci 2008; 28:1153-62. [PMID: 18234893 DOI: 10.1523/jneurosci.4105-07.2008] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Gamma oscillations have been implicated in higher cognitive processes and might critically depend on proper mitochondrial function. Using electrophysiology, oxygen sensor microelectrode, and imaging techniques, we investigated the interactions of neuronal activity, interstitial pO2, and mitochondrial redox state [NAD(P)H and FAD (flavin adenine dinucleotide) fluorescence] in the CA3 subfield of organotypic hippocampal slice cultures. We find that gamma oscillations and spontaneous network activity decrease significantly at pO2 levels that do not affect neuronal population responses as elicited by moderate electrical stimuli. Moreover, pO2 and mitochondrial redox states are tightly coupled, and electrical stimuli reveal transient alterations of redox responses when pO2 decreases within the normoxic range. Finally, evoked redox responses are distinct in somatic and synaptic neuronal compartments and show different sensitivity to changes in pO2. We conclude that the threshold of interstitial pO2 for robust CA3 network activities and required mitochondrial function is clearly above the "critical" value, which causes spreading depression as a result of generalized energy failure. Our study highlights the importance of a functional understanding of mitochondria and their implications on activities of individual neurons and neuronal networks.
Collapse
|
36
|
Lauwers F, Cassot F, Lauwers-Cances V, Puwanarajah P, Duvernoy H. Morphometry of the human cerebral cortex microcirculation: General characteristics and space-related profiles. Neuroimage 2008; 39:936-48. [DOI: 10.1016/j.neuroimage.2007.09.024] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 09/03/2007] [Accepted: 09/07/2007] [Indexed: 10/22/2022] Open
|
37
|
Nishimura N, Schaffer CB, Friedman B, Lyden PD, Kleinfeld D. Penetrating arterioles are a bottleneck in the perfusion of neocortex. Proc Natl Acad Sci U S A 2006; 104:365-70. [PMID: 17190804 PMCID: PMC1765467 DOI: 10.1073/pnas.0609551104] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Penetrating arterioles bridge the mesh of communicating arterioles on the surface of cortex with the subsurface microvascular bed that feeds the underlying neural tissue. We tested the conjecture that penetrating arterioles, which are positioned to regulate the delivery of blood, are loci of severe ischemia in the event of occlusion. Focal photothrombosis was used to occlude single penetrating arterioles in rat parietal cortex, and the resultant changes in flow of red blood cells were measured with two-photon laser-scanning microscopy in individual subsurface microvessels that surround the occlusion. We observed that the average flow of red blood cells nearly stalls adjacent to the occlusion and remains within 30% of its baseline value in vessels as far as 10 branch points downstream from the occlusion. Preservation of average flow emerges 350 mum away; this length scale is consistent with the spatial distribution of penetrating arterioles. We conclude that penetrating arterioles are a bottleneck in the supply of blood to neocortex, at least to superficial layers.
Collapse
Affiliation(s)
- Nozomi Nishimura
- Departments of *Physics and
- Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, CA 92093
| | - Chris B. Schaffer
- Departments of *Physics and
- Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, CA 92093
| | | | | | - David Kleinfeld
- Departments of *Physics and
- Graduate Program in Neurosciences, and
- Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, CA 92093
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
38
|
Dickie R, Bachoo RM, Rupnick MA, Dallabrida SM, Deloid GM, Lai J, Depinho RA, Rogers RA. Three-dimensional visualization of microvessel architecture of whole-mount tissue by confocal microscopy. Microvasc Res 2006; 72:20-6. [PMID: 16806289 DOI: 10.1016/j.mvr.2006.05.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 04/07/2006] [Accepted: 05/02/2006] [Indexed: 11/22/2022]
Abstract
The three-dimensional architecture of the nascent microvascular network is a critical determinant of vascular perfusion in the setting of regenerative growth, vasculopathies and cancer. Current methods for microvessel visualization are limited by insufficient penetration and instability of endothelial immunolabels, inadequate vascular perfusion by the high-viscosity polymers used for vascular casting, and destruction of tissue stroma during the processing required for scanning electron microscopy. The aim of this study was to develop whole-mount tissue processing methods for 3D in situ visualization of the microvasculature that were also compatible with supplementary labeling for other structures of interest in the tissue microenvironment. Here, we present techniques that allow imaging of the microvasculature by confocal microscopy, to depths of up to 1500 mum below the specimen surface. Our approach includes labeling luminal surfaces of endothelial cells by i.v. injection of fluorescently conjugated lectin and filling the microvasculature with carbon or fluorescent nanoparticles/Mercox, followed by optical clearing of thick tissue sections to reduce light scatter and permit 3D visualization of microvessel morphology deep into the sample. Notably, tissue stroma is preserved, allowing simultaneous labeling of other structures by immunohistochemistry or nuclear dyes. Results are presented for various murine tissues including fat, muscle, heart and brain under conditions of normal health, as well as in the setting of a glioma model growing in the subcutaneous space or orthotopically in the brain parenchyma.
Collapse
Affiliation(s)
- R Dickie
- Biomedical Imaging Laboratory, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Cassot F, Lauwers F, Fouard C, Prohaska S, Lauwers-Cances V. A Novel Three-Dimensional Computer-Assisted Method for a Quantitative Study of Microvascular Networks of the Human Cerebral Cortex. Microcirculation 2006; 13:1-18. [PMID: 16393942 DOI: 10.1080/10739680500383407] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Detailed information on microvascular network anatomy is a requirement for understanding several aspects of microcirculation, including oxygen transport, distributions of pressure, and wall shear stress in microvessels, regulation of blood flow, and interpretation of hemodynamically based functional imaging methods, but very few quantitative data on the human brain microcirculation are available. The main objective of this study is to propose a new method to analyze this microcirculation. METHODS From thick sections of india ink-injected human brain, using confocal laser microscopy, the authors developed algorithms adapted to very large data sets to automatically extract and analyze center lines together with diameters of thousands of brain microvessels within a large cortex area. RESULTS Direct comparison between the original data and the processed vascular skeletons demonstrated the high reliability of this method and its capability to manage a large amount of data, from which morphometry and topology of the cerebral microcirculation could be derived. CONCLUSIONS Among the many parameters that can be analyzed by this method, the capillary size, the frequency distributions of diameters and lengths, the fractal nature of these networks, and the depth-related density of vessels are all vital features for an adequate model of cerebral microcirculation.
Collapse
Affiliation(s)
- Francis Cassot
- Functional Neuroimaging Laboratory, INSERM U455, CHU Purpan, Toulouse, France.
| | | | | | | | | |
Collapse
|
40
|
Maddah M, Soltanian-Zadeh H, Afzali-Kusha A, Shahrokni A, Zhang ZG. Three-dimensional analysis of complex branching vessels in confocal microscopy images. Comput Med Imaging Graph 2005; 29:487-98. [PMID: 15996853 DOI: 10.1016/j.compmedimag.2005.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 03/12/2005] [Accepted: 03/12/2005] [Indexed: 10/25/2022]
Abstract
The characteristic of confocal microscopy (CM) vascular data is that it contains many tiny vessels with branching and complex structure. In this work, an automated method for quantitative analysis and reconstruction of cerebral vessels from CM images is presented in which the extracted centerline of the vessels plays the key role. To assess the efficiency and accuracy of different centerline extraction methods, a comparison among three fully automated approaches is given. The centerline extraction methods studied in this work are a snake model, a path planning approach, and a distance transform-based method. To evaluate the accuracy of the quantitative parameters of vessels such as length and diameter, we apply the method to synthetic data. These results indicate that the snake model and the path planning method are more accurate in extracting the quantitative parameters. The efficiency of the approach in clinical applications is then confirmed by applying the method to real CM images. All three methods investigated in this work are accurate enough to correctly distinguish between normal and stroke brain data, while the snake model is the fastest for clinical applications. In addition, three-dimensional visualization, reconstruction, and characterization of CM vascular images of rat brains are presented.
Collapse
Affiliation(s)
- Mahnaz Maddah
- Control and Intelligent Processing Center of Excellence, Department of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
| | | | | | | | | |
Collapse
|
41
|
Kretsos K, Kasting GB. Dermal capillary clearance: physiology and modeling. Skin Pharmacol Physiol 2005; 18:55-74. [PMID: 15767767 DOI: 10.1159/000083706] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Accepted: 10/07/2004] [Indexed: 11/19/2022]
Abstract
Substances applied to the skin surface may permeate deeper tissue layers and pass into the body's systemic circulation by entering blood or lymphatic vessels in the dermis. The purpose of this review is an in-depth analysis of the dermal clearance/exchange process and its constituents: transport through the interstitium, permeability of the microvascular barrier and removal via the circulation. We adapt an 'engineering' viewpoint with emphasis on quantifying the dermal microcirculatory physiology, providing the theoretical framework for the physics of key transport processes and reviewing the available computational clearance models in a comparative manner. Selected experimental data which may serve as valuable input to modeling attempts are also reported.
Collapse
Affiliation(s)
- K Kretsos
- University at Buffalo, State University of New York, Department of Chemical and Biological Engineering, Buffalo, NY, USA.
| | | |
Collapse
|
42
|
Soltanian-Zadeh H, Shahrokni A, Khalighi MM, Zhang ZG, Zoroofi RA, Maddah M, Chopp M. 3-D quantification and visualization of vascular structures from confocal microscopic images using skeletonization and voxel-coding. Comput Biol Med 2005; 35:791-813. [PMID: 16278109 DOI: 10.1016/j.compbiomed.2004.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2004] [Revised: 06/28/2004] [Accepted: 06/28/2004] [Indexed: 11/16/2022]
Abstract
This paper presents an image processing approach for information extraction from three-dimensional (3-D) images of vasculature. It extracts quantitative information such as skeleton, length, diameter, and vessel-to-tissue ratio for different vessels as well as their branches. Furthermore, it generates 3-D visualization of vessels based on desired anatomical characteristics such as vessel diameter or 3-D connectivity. Steps of the proposed approach are: (1) pre-processing, (2) distance mappings, (3) branch labeling, (4) quantification, and (5) visualization. We have tested and evaluated the proposed algorithms using simulated images of multi-branch vessels and real confocal microscopic images of the vessels in rat brains. Experimental results illustrate performance of the methods and usefulness of the results for medical image analysis applications.
Collapse
Affiliation(s)
- Hamid Soltanian-Zadeh
- Image Analysis Laboratory, Department of Radiology, Henry Ford Health System, Detroit, MI 48202, USA.
| | | | | | | | | | | | | |
Collapse
|
43
|
Grinberg OY, Hou H, Roche MA, Merlis J, Grinberg SA, Khan N, Swartz HM, Dunn JF. Modeling of the response of ptO2 in rat brain to changes in physiological parameters. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2005; 566:111-8. [PMID: 16594142 DOI: 10.1007/0-387-26206-7_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
It is known that oxygen tension in tissue (ptO2) will change in response to an alteration of physiological parameters including: pCO2 in arterial blood, blood flow, capillary density, oxygen carrying capacity, and p50 of hemoglobin. We have used modeling to compute the change of PtO2 in response to changes of each physiological parameter and related these changes to experimental data. The oxygen distribution in a Krogh cylinder was computed assuming a linear decrease of hemoglobin saturation from the arterial to the venous end of the capillary. Parameters of the model were used to compute the baseline cerebral PtO2 expressed as the mean value of the PtO2 over the whole cylinder. These parameters were adjusted to derive PtO2 values close to those measured at the relevant experimental conditions. Then each desired parameter was varied to calculate the change in PtO2 related to this parameter. Effects of different factors on cerebral PtO2 were modeled and compared with experimental values obtained with various experimental interventions including: changing CBF, modifying p50 with the allosteric modifier RSR13, modification of capillary density, and hemoglobin content. An acceptable agreement of the computed and the experimental changes of the cerebral PtO2 was obtained for these experimental conditions.
Collapse
|
44
|
Abstract
The present study describes quick and effective methods that allow visualization of the vascular endothelium in living networks within dissected pieces of human tissue or in primary cultures containing heterogeneous cell populations. Fresh human uterine and subcutaneous gluteal fat tissues were directly labelled using fluorescently conjugated Ulex Europaeus Agglutinin I (UEA-1) to visualize the three-dimensional nature of the vascular network. Using conventional epi-illuminescence microscopy, the convoluted architecture demonstrating branch points within capillaries, between capillaries and larger vessels, were clearly observed in uterine and subcutaneous gluteal fat samples. In adult endometrial tissue where angiogenesis occurs on a monthly basis, complex anastamosis of vessels and tenuous structures were clearly seen. Three-dimensional rendered surface models formed by examination of confocal z-stacks demonstrated the existence of the lumen within microvessels. Tissue prelabelled with UEA-1 was used to assist and verify the presence of endothelial cells in culture, during and after the isolation procedure. Additionally, UEA-1 was added to a uterine fibroblast-microvascular-endothelial cell coculture model to allow daily vital observations of changes in the phenotype of the endothelium. The simple techniques described here demonstrate the ease with which fluorescently labelled UEA-1 can be used as a vital marker of endothelial cells either in tissue or in a tube-forming human uterine microvascular culture model.
Collapse
Affiliation(s)
- Shabaz A Hamid
- Division of Developmental Medicine, University of Glasgow, Level 3, Queen Elizabeth Building, Glasgow Royal Infirmary, 10 Alexandra Parade, Glasgow G31 2ER, UK
| | | | | |
Collapse
|
45
|
Schulte ML, Wood JD, Hudetz AG. Cortical electrical stimulation alters erythrocyte perfusion pattern in the cerebral capillary network of the rat. Brain Res 2003; 963:81-92. [PMID: 12560113 DOI: 10.1016/s0006-8993(02)03848-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effect of direct cortical electrical stimulation on the pattern of erythrocyte perfusion in the capillary network of the rat cerebral cortex was studied by fluorescence intravital video-microscopy. The movement of fluorescently labeled red blood cells (FRBCs) in individual capillaries 50-70 microm subsurface in the dorsal somatosensory cortex was visualized using a closed cranial window. Cortical stimulation electrodes were placed on opposite sides of the window. FRBC velocity (mm/s) and supply rate (cells/s) were measured in 51 capillaries from six rats before and during electrical stimulation of increasing intensities (15-s trains of 3-Hz, 3-ms, 0.5-5.0-mA, square pulses). FRBC velocity, supply rate, and the instantaneous capillary erythrocyte content (lineal cell density, LCD, cells/mm) increased with the stimulation current and reached maxima of 110, 160 and 33% above control, respectively. Capillaries with low resting velocity showed a greater response than those with high resting velocity. The fraction of capillaries in which FRBC velocity increased was not constant, but increased with the stimulation current, as did the magnitude of the velocity change in these capillaries. A few capillaries showed a negative FRBC velocity response at stimulations <4 mA. These results suggest that a robust rise in the fraction of responding (engaged) capillaries and a smaller rise in the capillary LCD contribute to neuronal activation-induced cortical hyperemia. Thus, capillary engagement and erythrocyte recruitment appear to represent important components of the cortical functional hyperemic response. These results provide insight into some of the specific hemodynamic changes associated with functional hyperemia occurring at the capillary level.
Collapse
Affiliation(s)
- M L Schulte
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | | | | |
Collapse
|