Display Settings:

Items per page

Results: 6

1.
Figure 6

Figure 6. From: In vivo imaging of cerebral microvascular plasticity from birth to death.

Hypoxia-induced vessel formation is dramatically reduced in mature brains. (A) Representative image from a 25-month-old mouse showing microvascular stability and lack of angiogenesis despite exposure to 10% hypoxia over a 1-month interval. (B) Branch point formation and elimination quantified as a percentage of total branch points at TP1 after a 1-month imaging interval. There are no significant differences in vessel formation or elimination between hypoxic brains and their normoxic controls in both adult and aging mice; however, in younger adults hypoxic exposure significantly and preferentially increases vessel formation. Factorial analysis of variance (ANOVA) (age × oxygen level interaction): F(2,18)=20.08, P<0.0001; post-hoc Tukey's tests: P>0.05 for aging vessel formation and P<0.001 for adult vessel formation under hypoxia (n=5,557 branch points; 24 animals). Scale bar: 10 μm; values are presented as mean+s.e.m; *P<0.05 throughout.

Roa Harb, et al. J Cereb Blood Flow Metab. 2013 January;33(1):146-156.
2.
Figure 2

Figure 2. From: In vivo imaging of cerebral microvascular plasticity from birth to death.

Short-distance sprouting occurs without local endothelial proliferation. (AC), Confocal images of DiI-labeled vessels in P4 mice showing protruding vascular sprouts with numerous filopodia. At this early age, 4′,6-diamidino-2-phenylindole (DAPI) staining reveals that sprouts span short distances and are usually unicellular (Ai, asterix); in some cases tip cell nuclei may remain within the parent vessel (Bi, Ci) entailing that sprouts may reach their nearby targets through the extension of cellular processes (C). (D, E), IsolectinB4-labeled sprout (green) exists in the absence of local endothelial cell proliferation using BrdU (D) or Ki67 (E) proliferation markers (red). (F, H), Collagen IV-labeled structures (green, arrowheads) that may be sprouts, anastomosed segments, or retracting vessels are not adjacent to proliferating endothelial cells (BrdU, red). (H, I) Collagen IV/DAPI staining shows that thin Collagen IV structures may contain a nucleus (H) or be acellular (I). Scale bars: (AF) 10 μm; (GI) 5 μm.

Roa Harb, et al. J Cereb Blood Flow Metab. 2013 January;33(1):146-156.
3.
Figure 1

Figure 1. From: In vivo imaging of cerebral microvascular plasticity from birth to death.

The brain microvasculature undergoes extensive endothelial proliferation and branching in the first postnatal month. (A) Confocal images from Collagen IV (green)- and BrdU (red)-labeled cortical sections showing increasing branching in the postnatal period. The majority of BrdU-labeled cells are located outside vessels and thus are not endothelial. (B) An example of higher magnification images used to distinguish endothelial BrdU nuclei from other perivascular nuclei. (C) Quantification of changes in branching and endothelial cell proliferation in the postnatal period shows that branching plateaus between P15 and P25 while endothelial cell proliferation peaks around P10. One-way analysis of variance (ANOVA) (branching): F(5,19)=40.60, P<0.0001. One-way ANOVA (endothelial proliferation): F(5,19)=22.81, P<0.0001. Values are presented as mean+s.e.m. (D) Quantification of vessel length (mm/mm3) in a fixed tissue volume reveals an increase over time. Analysis of endothelial BrdU and total BrdU (cells/mm2) reveals that while endothelial proliferation peaks postnatally, nonendothelial proliferation declines steadily after birth, reaching near-zero levels by p10. (E) Collagen IV labeling shows that vascular branching and vessel length increase over the first postnatal month are highly correlated (r=0.76). Each purple circle represents a single animal (animals used were ages p0, p4, p15, and p25). Black lines denote 95% confidence intervals. Scale bars: (A) 200 μm; (B) 5 μm.

Roa Harb, et al. J Cereb Blood Flow Metab. 2013 January;33(1):146-156.
4.
Figure 3

Figure 3. From: In vivo imaging of cerebral microvascular plasticity from birth to death.

Microvascular patterning occurs through concurrent vascular formation and elimination. (A) Two-photon imaging through thinned skull of neonatal Tie2–GFP pups for time-lapse imaging at various ages between P7 and P12. (BG) Using Tie2–GFP to label endothelial cells and an intravascular fluorescent dye (clear blue), the same vascular structures can be observed over a time interval of 30 hours. Dynamic changes include sprout formation (B, Bi, yellow arrowheads) and elimination (D, Di, blue arrowheads) as well as vessel formation (C, Ci, yellow arrowheads) and elimination (E, Ei, blue arrowheads). Some sprouts contained a trickle of plasma (F, red arrowheads) whereas others were unperfused (F, white arrowheads). Unperfused vessels (G, white arrowheads) were partially (Gi, green arrowhead) or fully (Gi, red arrowheads) perfused at a second time point. (H) Sprout outcome quantified as a percentage of total branch points at TP1. The majority of sprouts were eliminated by the second time point of imaging. One-way analysis of variance (ANOVA): F(2, 15)=26.81, P<0.0001; post-hoc Tukey's tests: P<0.001 (n=98 sprouts; six animals). (I) Newly perfused vessels or sprouts quantified as percentages of total lumenization events at TP2. Establishment of flow was significantly more likely to occur following complete anastomosis than concurrent with the sprout growth. χ2 test: P<0.0001 (n=45 new perfusions, six animals). (J) Eliminated vessels or sprouts quantified as percentages of total eliminations at TP2. Sprouts were significantly more likely to get eliminated than vessels. χ2 test: P<0.0001 (n=83 eliminations, six animals). Values are presented as mean+s.e.m; *P<0.05 throughout. Scale bar: 20 μm.

Roa Harb, et al. J Cereb Blood Flow Metab. 2013 January;33(1):146-156.
5.
Figure 4

Figure 4. From: In vivo imaging of cerebral microvascular plasticity from birth to death.

Long-term microvessel stability in adulthood by low-level turnover is lost in aging. (AF, H), Two-photon time-lapse imaging of microvessels labeled with intravascular thioflavin-S (TS). (A, B), Ongoing vascular remodeling towards the end of the first postnatal month (24 to 31 day age group). (A) Representative images showing sprout growth into a fully connected vessel (blue arrowheads) over a 1-month imaging interval. Sprouting was not observed in older age groups. (B) Representative images showing vessel elimination (yellow arrowhead) and vessel formations (red arrowheads) in close proximity over a 1-month imaging interval. (C, D), Microvascular stability in the maturing brain is concomitant with low-level turnover (32 to 50 day age group). Representative images showing largely unchanged vascular structures over a 1-month imaging interval with one vessel elimination (C, yellow arrowhead) and one vessel formation (D, red arrowhead) observed in two separate areas. (E, F), Microvascular stability and low-level turnover is persistently seen in older adults (74 to 94 day age groups). Representative images showing unchanged vascular structures over a 1-month imaging interval (F) and a single vessel elimination (E, yellow arrowhead) observed in two separate areas. (G) Quantification of branch point formation and elimination during a 1-month imaging interval (percentage of total branch points at TP1). Microvascular formation and elimination are significantly higher in the 24 to 31 day age group compared with older mice; however, only the aging group displays complete absence of vascular remodeling. One-way analysis of variance (ANOVA): F(6, 16)=6.8437, P<0.001; post-hoc Tukey's tests: P<0.05 (n=4,209 branch points; 13 animals). (H) Representative images from a 22-month-old mouse showing remarkable microvascular stability over a 7-month interval. No elimination or formation events were noted for this group. Scale bar: 10 μm; values are presented as mean+s.e.m; *P<0.05 throughout.

Roa Harb, et al. J Cereb Blood Flow Metab. 2013 January;33(1):146-156.
6.
Figure 5

Figure 5. From: In vivo imaging of cerebral microvascular plasticity from birth to death.

Reduced oxygen triggers sprouting angiogenesis in the young adult brain but newly formed vessels remain stable in the long term. (A, B) Two-photon images before and after hypoxia showing multiple vessel formations (red arrowheads) and sprout formation (blue arrowhead) over a 1-month imaging interval. (C) Representative confocal images of dual perfusion with FITC-dextran and DiI after 15 days of 10% hypoxia exposure showing the presence of a partially perfused sprout (blue arrowhead). (D, E), Branch point formation and elimination quantified as a percentage of total branch points at TP1 after a 1-month imaging interval. (D) Exposure to 10% hypoxia over a 1-month interval causes a robust increase in vessel formation as compared with normoxic controls and mice exposed to 15% hypoxia but it has no effect on vessel elimination. One-way analysis of variance (ANOVA): F(4,16)=6.0121, P<0.01; post-hoc Tukey's tests: P<0.001 (n=2,542 branch points; 12 animals). (E) Vessel formation is significantly increased and reaches a plateau after 14 days of exposure to 10% hypoxia. Factorial ANOVA (oxygen level × duration of hypoxia interaction): F(4, 34)=3.6853, P=0.01; post-hoc Tukey's tests: P<0.05 (n=3,665 branch points; 24 animals). (F) Branch point formation and elimination quantified as a percentage of total branch points counted at each preceding imaging point. Reestablishment of normoxia following a hypoxic exposure does not lead to increased rates of vessel elimination. Paired t-tests: P>0.05 (n=252 branch points; four animals). (G) Long-term imaging across three time points from a prehypoxic baseline to reestablishment of normoxia. This panel shows the formation of a new a blood vessel after the first hypoxic exposure (day 30, red arrowhead) and its persistence through reestablishment of normoxia (day 86, white arrowhead). Scale bar: 10 μm; values are presented as mean+s.e.m; *P<0.05 throughout.

Roa Harb, et al. J Cereb Blood Flow Metab. 2013 January;33(1):146-156.

Display Settings:

Items per page

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...
Write to the Help Desk