Development of an optimal systemic drug delivery strategy to the brain will require noninvasive or minimally invasive methods to quantify the permeability of the cerebral microvessel wall or blood-brain barrier (BBB) to various therapeutic agents and to measure their transport in the brain tissue. To address this problem, we used laser-scanning multiphoton microscopy to determine BBB permeability to solutes (P) and effective solute diffusion coefficients (Deff) in rat brain tissue 100–250 μm below the pia mater. The cerebral microcirculation was observed through a section of frontoparietal bone thinned with a microgrinder. Sodium fluorescein, fluorescein isothiocyanate (FITC)-dextrans, or Alexa Fluor 488-immunoglobulin G (IgG) in 1% bovine serum albumin (BSA) mammalian Ringer's solution was injected into the cerebral circulation via the ipsilateral carotid artery by a syringe pump at a constant rate of ∼3 ml/min. P and Deff were determined from the rate of tissue solute accumulation and the radial concentration gradient around individual microvessels in the brain tissue. The mean apparent permeability P values for sodium fluorescein (molecular weight (MW) 376 Da), dextran-4k, -20k, -40k, -70k, and IgG (MW ∼160 kDa) were 14.6, 6.2, 1.8, 1.4, 1.3, and 0.54 × 10−7 cm/s, respectively. These P values were not significantly different from those of rat pial microvessels for the same-sized solutes (Yuan et al., 2009, “Non-Invasive Measurement of Solute Permeability in Cerebral Microvessels of the Rat,” Microvasc. Res., 77(2), pp. 166–73), except for the small solute sodium fluorescein, suggesting that pial microvessels can be a good model for studying BBB transport of relatively large solutes. The mean Deff values were 33.2, 4.4, 1.3, 0.89, 0.59, and 0.47 × 10−7 cm2/s, respectively, for sodium fluorescein, dextran-4k, -20k, -40k, -70k, and IgG. The corresponding mean ratio of Deff to the free diffusion coefficient Dfree, Deff/Dfree, were 0.46, 0.19, 0.12, 0.12, 0.11, and 0.11 for these solutes. While there is a significant difference in Deff/Dfree between small (e.g., sodium fluorescein) and larger solutes, there is no significant difference in Deff/Dfree between solutes with molecular weights from 20,000 to 160,000 Da, suggesting that the relative resistance of the brain tissue to macromolecular solutes is similar over a wide size range. The quantitative transport parameters measured from this study can be used to develop better strategies for brain drug delivery.

References

References
1.
de Lange
,
E. C.
,
de Boer
,
B. A.
, and
Breimer
,
D. D.
,
1999
, “
Microdialysis for Pharmacokinetic Analysis of Drug Transport to the Brain
,”
Adv. Drug Delivery Rev.
,
36
(
2–3
), pp.
211
227
.10.1016/S0169-409X(98)00089-1
2.
Wang
,
R.
,
Ashwal
,
S.
,
Tone
,
B.
,
Tian
,
H. R.
,
Badaut
,
J.
,
Rasmussen
,
A.
, and
Obenaus
,
A.
,
2007
, “
Albumin Reduces Blood-Brain Barrier Permeability but Does Not Alter Infarct Size in a Rat Model of Neonatal Stroke
,”
Pediatr. Res.
,
62
(
3
), pp.
261
266
.10.1203/PDR.0b013e318123f757
3.
Cornford
,
E. M.
,
Young
,
D.
,
Paxton
,
J. W.
, and
Sofia
,
R. D.
,
1992
, “
Blood-Brain Barrier Penetration of Felbamate
,”
Epilepsia
,
33
(
5
), pp.
944
954
.10.1111/j.1528-1157.1992.tb02205.x
4.
van Uitert
,
R. L.
,
Sage
,
J. I.
,
Levy
,
D. E.
, and
Duffy
,
T. E.
,
1981
, “
Comparison of Radio-Labeled Butanol and Iodoantipyrine as Cerebral Blood Flow Markers
,”
Brain Res.
,
222
(
2
), pp.
365
372
.10.1016/0006-8993(81)91039-8
5.
Zlokovic
,
B. V.
,
Begley
,
D. J.
,
Djuricic
,
B. M.
, and
Mitrovic
,
D. M.
,
1986
, “
Measurement of Solute Transport Across the Blood-Brain Barrier in the Perfused Guinea Pig Brain: Method and Application to N-Methyl-Alpha-Aminoisobutyric Acid
,”
J. Neurochem.
,
46
(
5
), pp.
1444
1451
.10.1111/j.1471-4159.1986.tb01760.x
6.
Crone
,
C.
,
1963
, “
Permeability of Capillaries in Various Organs as Determined by Use of Indicator Diffusion Method
,”
Acta Physiol. Scand.
,
58
(
4
), pp.
292
305
.10.1111/j.1748-1716.1963.tb02652.x
7.
Easton
,
A. S.
, and
Fraser
,
P. A.
,
1994
, “
Variable Restriction of Albumin Diffusion Across Inflamed Cerebral Microvessels of the Anaesthetized Rat
,”
J. Physiol.
,
475
(
1
), pp.
147
157
.
8.
Elsinga
,
P. H.
,
Hendrikse
,
N. H.
,
Bart
,
J.
,
Vaalburg
,
W.
, and
van Waarde
,
A.
,
2004
, “
PET Studies on P-Glycoprotein Function in the Blood-Brain Barrier: How It Affects Uptake and Binding of Drugs Within the CNS
,”
Curr. Pharm. Des.
,
10
(
13
), pp.
1493
1503
.10.2174/1381612043384736
9.
Gaber
,
M. W.
,
Yuan
,
H.
,
Killmar
,
J. T.
,
Naimark
,
M. D.
,
Kiani
,
M. F.
, and
Merchant
,
T. E.
,
2004
, “
An Intravital Microscopy Study of Radiation-Induced Changes in Permeability and Leukocyte-Endothelial Cell Interactions in the Microvessels of the Rat Pia Mater and Cremaster Muscle
,”
Brain Res. Brain Res. Protoc.
,
13
(
1
), pp.
1
10
.10.1016/j.brainresprot.2003.11.005
10.
Yuan
,
H.
,
Gaber
,
M. W.
,
McColgan
,
T.
,
Naimark
,
M. D.
,
Kiani
,
M. F.
, and
Merchant
,
T. E.
,
2003
, “
Radiation-Induced Permeability and Leukocyte Adhesion in the Rat Blood-Brain Barrier: Modulation With Anti-ICAM-1 Antibodies
,”
Brain Res.
,
969
(
1–2
), pp.
59
69
.10.1016/S0006-8993(03)02278-9
11.
Berk
,
D. A.
,
Yuan
,
F.
,
Leunig
,
M.
, and
Jain
,
R. K.
,
1997
, “
Direct in vivo Measurement of Targeted Binding in a Human Tumor Xenograft
,”
Proc. Natl. Acad. Sci. USA
,
94
(
5
), pp.
1785
1790
.10.1073/pnas.94.5.1785
12.
Chary
,
S. R.
, and
Jain
,
R. K.
,
1989
, “
Direct Measurement of Interstitial Convection and Diffusion of Albumin in Normal and Neoplastic Tissues by Fluorescence Photobleaching
,”
Proc. Natl. Acad. Sci. USA
,
86
(
14
), pp.
5385
5389
.10.1073/pnas.86.14.5385
13.
Flessner
,
M. F.
,
Lofthouse
,
J.
, and
Zakaria
,
el-R.
,
1997
, “
In Vivo Diffusion of Immunoglobulin G in Muscle: Effects of Binding, Solute Exclusion, and Lymphatic Removal
,”
Am. J. Physiol.
,
273
(
6 Pt 2
), pp.
H2783
H2793
.
14.
Fox
,
J. R.
, and
Wayland
,
H.
,
1979
, “
Interstitial Diffusion of Macromolecules in the Rat Mesentery
,”
Microvasc. Res.
,
18
(
2
), pp.
255
276
.10.1016/0026-2862(79)90033-5
15.
Granger
,
H. J.
, and
Taylor
,
A. E.
,
1975
, “
Permeability of Connective Tissue Linings Isolated From Implanted Capsules: Implications for Interstitial Pressure Measurements
,”
Circ. Res.
,
36
(
1
), pp.
222
228
.10.1161/01.RES.36.1.222
16.
Jain
,
R. K.
,
Stock
,
R. J.
,
Chary
,
S. R.
, and
Rueter
,
M.
,
1990
, “
Convection and Diffusion Measurements Using Fluorescence Recovery After Photobleaching and Video Image Analysis: in Vitro Calibration and Assessment
,”
Microvasc. Res.
,
39
(
1
), pp.
77
93
.10.1016/0026-2862(90)90060-5
17.
Nicholson
,
C.
,
2001
, “
Diffusion and Related Transport Mechanisms in Brain Tissue
,”
Rep. Prog. Phys.
,
64
(
7
), pp.
815
884
.10.1088/0034-4885/64/7/202
18.
Nicholson
,
C.
, and
Tao
,
L.
,
1993
, “
Hindered Diffusion of High Molecular Weight Compounds in Brain Extracellular Microenvironment Measured With Integrative Optical Imaging
,”
Biophys. J.
,
65
(
6
), pp.
2277
2290
.10.1016/S0006-3495(93)81324-9
19.
Tao
,
L.
, and
Nicholson
,
C.
,
1996
, “
Diffusion of Albumins in Rat Cortical Slices and Relevance to Volume Transmission
,”
Neuroscience
,
75
(
3
), pp.
839
847
.10.1016/0306-4522(96)00303-X
20.
Stroh
,
M.
,
Zipfel
,
W. R.
,
Williams
,
R. M.
,
Webb
,
W. W.
, and
Saltzman
,
W. M.
,
2003
, “
Diffusion of Nerve Growth Factor in Rat Striatum as Determined by Multiphoton Microscopy
,”
Biophys. J.
,
85
(
1
), pp.
581
588
.10.1016/S0006-3495(03)74502-0
21.
Binder
,
D. K.
,
Papadopoulos
,
M. C.
,
Haggie
,
P. M.
, and
Verkman
,
A. S.
,
2004
, “
In Vivo Measurement of Brain Extracellular Space Diffusion by Cortical Surface Photobleaching
,”
J. Neurosci.
,
24
(
37
), pp.
8049
8056
.10.1523/JNEUROSCI.2294-04.2004
22.
Thorne
,
R. G.
, and
Nicholson
,
C.
,
2006
, “
In Vivo Diffusion Analysis With Quantum Dots and Dextrans Predicts the Width of Brain Extracellular Space
,”
Proc. Natl. Acad. Sci. USA
,
103
(
14
), pp.
5567
5572
.10.1073/pnas.0509425103
23.
Thorne
,
R. G.
,
Lakkaraju
,
A.
,
Rodriguez-Boulan
,
E.
, and
Nicholson
,
C.
,
2008
, “
In Vivo Diffusion of Lactoferrin in Brain Extracellular Space Is Regulated by Interactions With Heparan Sulfate
,”
Proc. Natl. Acad. Sci. USA
,
105
(
24
), pp.
8416
8421
.10.1073/pnas.0711345105
24.
Adamson
,
R. H.
,
Lenz
,
J. F.
, and
Curry
,
F. E.
,
1994
, “
Quantitative Laser Scanning Confocal Microscopy on Single Capillaries: Permeability Measurement
,”
Microcirculation
,
1
(
4
), pp.
251
265
.10.3109/10739689409146752
25.
Fu
,
B. M.
,
Curry
,
F. E.
, and
Weinbaum
,
S.
,
1995
, “
A Diffusion Wake Model for Tracer Ultrastructure-Permeability Studies in Microvessels
,”
Am. J. Physiol.
,
269
(
6 Pt 2
), pp.
H2124
H2140
.
26.
Fu
,
B. M.
,
Adamson
,
R. H.
, and
Curry
,
F. R.
,
2005
, “
Determination of Microvessel Permeability and Tissue Diffusion Coefficient of Solutes by Laser Scanning Confocal Microscopy
,”
ASME J. Biomech. Eng.
,
127
(
2
), pp.
270
278
.10.1115/1.1865186
27.
Yuan
,
W.
,
Lv
,
Y.
,
Zeng
,
M.
, and
Fu
,
B. M.
,
2009
, “
Non-invasive Measurement of Solute Permeability in Cerebral Microvessels of the Rat
,”
Microvasc. Res.
,
77
(
2
), pp.
166
173
.10.1016/j.mvr.2008.08.004
28.
Fu
,
B. M.
, and
Shen
,
S.
,
2004
, “
Acute VEGF Effect on Solute Permeability of Mammalian Microvessels in vivo
,”
Microvasc. Res.
,
68
(
1
), pp.
51
62
.10.1016/j.mvr.2004.03.004
29.
Fu
,
B. M.
,
Adamson
,
R. H.
, and
Curry
,
F. E.
,
1998
, “
Test of a Two-Pathway Model for Small-Solute Exchange Across the Capillary Wall
,”
Am. J. Physiol.
,
274
(
6 Pt 2
), pp.
H2062
H2073
.
30.
Easton
,
A. S.
,
Sarker
,
M. H.
, and
Fraser
,
P. A.
,
1997
, “
Two Components of Blood-Brain Barrier Disruption in the Rat
,”
J. Physiol.
,
503
(Pt
3
), pp.
613
623
.10.1111/j.1469-7793.1997.613bg.x
31.
Evans
,
A. J.
,
James
,
J. J.
,
Cornford
,
E. J.
,
Chan
,
S. Y.
,
Burrell
,
H. C.
,
Pinder
,
S. E.
,
Gutteridge
,
E.
,
Robertson
,
J. F.
,
Hornbuckle
,
J.
, and
Cheung
,
K. L.
,
2004
, “
Brain Metastases From Breast Cancer: Identification of a High-Risk Group
,”
Clin. Oncol. (R. Coll. Radiol.)
,
16
(
5
), pp.
345
349
.10.1016/j.clon.2004.03.012
32.
Friedman
,
J. H.
,
Koller
,
W. C.
,
Lannon
,
M. C.
,
Busenbark
,
K.
,
Swanson-Hyland
,
E.
, and
Smith
,
D.
,
1997
, “
Benztropine Versus Clozapine for the Treatment of Tremor in Parkinson's Disease
,”
Neurology
,
48
(
4
), pp.
1077
1081
.10.1212/WNL.48.4.1077
33.
Jansen
,
E. N.
,
1994
, “
Clozapine in the Treatment of Tremor in Parkinson's Disease
,”
Acta Neurol. Scand.
,
89
(
4
), pp.
262
265
.10.1111/j.1600-0404.1994.tb01677.x
34.
Lieberman
,
J. A.
, and
Stroup
,
T. S.
,
2011
, “
The NIMH-CATIE Schizophrenia Study: What Did We Learn?
,”
Am. J. Psychiatry
,
168
(
8
), pp.
770
775
.10.1176/appi.ajp.2011.11010039
35.
Jones
,
P. B.
,
Barnes
,
T. R.
,
Davies
,
L.
,
Dunn
,
G.
,
Lloyd
,
H.
,
Hayhurst
,
K. P.
,
Murray
,
R. M.
,
Markwick
,
A.
, and
Lewis
,
S. W.
,
2006
, “
Randomized Controlled Trial of the Effect on Quality of Life of Second- vs First-Generation Antipsychotic Drugs in Schizophrenia: Cost Utility of the Latest Antipsychotic Drugs in Schizophrenia Study (CUtLASS 1)
,”
Arch. Gen. Psychiatry
,
63
(
10
), pp.
1079
1087
.10.1001/archpsyc.63.10.1079
36.
Brown
,
R. C.
,
Egleton
,
R. D.
, and
Davis
,
T. P.
,
2004
, “
Mannitol Opening of the Blood-Brain Barrier: Regional Variation in the Permeability of Sucrose, but Not 86Rb+ or Albumin
,”
Brain Res.
,
1014
(
1–2
), pp.
221
227
.10.1016/j.brainres.2004.04.034
37.
Garcia-Villalon
,
A. L.
,
Roda
,
J. M.
,
Alvarez
,
F.
,
Gomez
,
B.
, and
Dieguez
,
G.
,
1992
, “
Carotid Blood Flow in Anesthetized Rats: Effects of Carotid Ligation and Anastomosis
,”
Microsurgery
,
13
(
5
), pp.
258
261
.10.1002/micr.1920130513
38.
Pardridge
,
W. M.
,
1998
, “
CNS Drug Design Based on Principles of Blood-Brain Barrier Transport
,”
J. Neurochem.
,
70
(
5
), pp.
1781
1792
.10.1046/j.1471-4159.1998.70051781.x
39.
Curry
,
F. E.
, and
Frokjaer-Jensen
,
J.
,
1984
, “
Water Flow Across the Walls of Single Muscle Capillaries in the Frog, Rana Pipiens
,”
J. Physiol.
,
350
, pp.
293
307
.
40.
Fu
,
B. M.
, and
Shen
,
S.
,
2003
, “
Structural Mechanisms of Acute VEGF Effect on Microvessel Permeability
,”
Am. J. Physiol. Heart Circ. Physiol.
,
284
(
6
), pp.
H2124
H2135
.DOI: 10.1152/ajpheart.00894.2002
41.
Kendall
,
S.
, and
Michel
,
C. C.
,
1995
, “
The Measurement of Permeability in Single Rat Venules Using the Red Cell Microperfusion Technique
,”
Exp. Physiol.
,
80
(
3
), pp.
359
372
.
42.
Fraser
,
P. A.
,
Dallas
,
A. D.
, and
Davies
,
S.
,
1990
, “
Measurement of Filtration Coefficient in Single Cerebral Microvessels of the Frog
,”
J. Physiol.
,
423
, pp.
343
361
.
43.
Kimura
,
M.
,
Dietrich
,
H. H.
,
Huxley
,
V. H.
,
Reichner
,
D. R.
, and
Dacey
,
R. G.
, Jr.
,
1993
, “
Measurement of Hydraulic Conductivity in Isolated Arterioles of Rat Brain Cortex
,”
Am. J. Physiol.
,
264
(
6 Pt 2
), pp.
H1788
H1797
.
44.
Roberts
,
T. J.
,
Chapman
,
A. C.
, and
Cipolla
,
M. J.
,
2009
, “
PPAR-Gamma Agonist Rosiglitazone Reverses Increased Cerebral Venous Hydraulic Conductivity During Hypertension
,”
Am. J. Physiol. Heart Circ. Physiol.
,
297
(
4
), pp.
H1347
H1353
.10.1152/ajpheart.00630.2009
45.
Chen
,
B.
, and
Fu
,
B. M. M.
,
2009
, “
A Time-Dependent Electrodiffusion-Convection Model for Charged Macromolecule Transport Across the Microvessel Wall and in the Interstitial Space
,”
Cell. Mol. Bioeng.
,
2
(
4
), pp.
514
532
.10.1007/s12195-009-0074-6
46.
Fu
,
B.
,
Curry
,
F. R.
,
Adamson
,
R. H.
, and
Weinbaum
,
S.
,
1997
, “
A Model for Interpreting the Tracer Labeling of Interendothelial Clefts
,”
Ann. Biomed. Eng.
,
25
(
2
), pp.
375
397
.10.1007/BF02648050
47.
Tao
,
L.
,
1999
, “
Effects of Osmotic Stress on Dextran Diffusion in Rat Neocortex Studied With Integrative Optical Imaging
,”
J. Neurophysiol.
,
81
(
5
), pp.
2501
2507
.
48.
Thorne
,
R. G.
,
Hrabetova
,
S.
, and
Nicholson
,
C.
,
2004
, “
Diffusion of Epidermal Growth Factor in Rat Brain Extracellular Space Measured by Integrative Optical Imaging
,”
J. Neurophysiol.
,
92
(
6
), pp.
3471
3481
.10.1152/jn.00352.2004
49.
Tsai
,
P. S.
,
Friedman
,
B.
,
Ifarraguerri
,
A. I.
,
Thompson
,
B. D.
,
Lev-Ram
,
V.
,
Schaffer
,
C. B.
,
Xiong
,
Q.
,
Tsien
,
R. Y.
,
Squier
,
J. A.
, and
Kleinfeld
,
D.
,
2003
, “
All-Optical Histology Using Ultrashort Laser Pulses
,”
Neuron
,
39
(
1
), pp.
27
41
.10.1016/S0896-6273(03)00370-2
50.
Chen
,
B.
,
Pogue
,
B. W.
,
Luna
,
J. M.
,
Hardman
,
R. L.
,
Hoopes
,
P. J.
, and
Hasan
,
T.
,
2006
, “
Tumor Vascular Permeabilization by Vascular-Targeting Photosensitization: Effects, Mechanism, and Therapeutic Implications
,”
Clin. Cancer Res.
,
12
(
3 Pt 1
), pp.
917
923
.10.1158/1078-0432.CCR-05-1673
51.
Rueckel
,
M.
,
Mack-Bucher
,
J. A.
, and
Denk
,
W.
,
2006
, “
Adaptive Wavefront Correction in Two-Photon Microscopy Using Coherence-Gated Wavefront Sensing
,”
Proc. Natl. Acad. Sci. USA
,
103
(
46
), pp.
17137
17142
.10.1073/pnas.0604791103
52.
Chaigneau
,
E.
,
Wright
,
A. J.
,
Poland
,
S. P.
,
Girkin
,
J. M.
, and
Silver
,
R. A.
,
2011
, “
Impact of Wavefront Distortion and Scattering on 2-Photon Microscopy in Mammalian Brain Tissue
,”
Opt. Exp.
,
19
(
23
), pp.
22755
22774
.10.1364/OE.19.022755
53.
Sun
,
Y.
,
2000
, “
Hopfield Neural Network Based Algorithms for Image Restoration and Reconstruction - Part I: Algorithms and Simulations
,”
IEEE Trans. Signal Process.
,
48
(
7
), pp.
2105
2118
.10.1109/78.847794
54.
Sun
,
Y.
,
2009
, “
A Family of Likelihood Ascent Search Multiuser Detectors: Approaching Optimum Performance via Random Multicodes With Linear Complexity
,”
IEEE Trans. Commun.
,
57
(
8
), pp.
2215
2220
.10.1109/TCOMM.2009.08.070153
55.
Rusek
,
F.
,
Persson
,
D.
,
Lau
,
B. K.
,
Larsson
,
E. G.
,
Marzetta
,
T. L.
,
Edfors
,
O.
, and
Tufvesson
,
F.
,
2013
, “
Scaling Up MIMO
,”
IEEE Signal Process. Mag.
,
30
(
1
), pp.
40
60
.10.1109/MSP.2011.2178495
56.
Sun
,
Y.
,
2000
, “
Hopfield Neural Network Based Algorithms for Image Restoration and Reconstruction - Part II: Performance Analysis
,”
IEEE Trans. Signal Process.
,
48
(
7
), pp.
2119
2131
.10.1109/78.847795
You do not currently have access to this content.