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Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.

Banks WA, Gray AM, Erickson MA, Salameh TS, Damodarasamy M, Sheibani N, Meabon JS, Wing EE, Morofuji Y, Cook DG, Reed MJ - J Neuroinflammation (2015)

Bottom Line: N-acetylcysteine did not affect disruption.In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

View Article: PubMed Central - PubMed

Affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. wabanks1@uw.edu.

ABSTRACT

Background: Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain.

Methods: We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin.

Results: In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.

Conclusions: The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

No MeSH data available.


Related in: MedlinePlus

Dose-dependence of LPS on BBB permeability to 14C-Sucrose. Only the 3 mg/kg dose increased BBB permeability. **p < 0.01, n = 9/group
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Fig1: Dose-dependence of LPS on BBB permeability to 14C-Sucrose. Only the 3 mg/kg dose increased BBB permeability. **p < 0.01, n = 9/group

Mentions: Mice were studied 24 h after a single IP injection of LPS. The highest dose of LPS (3 mg/kg) administered to CD-1 mice produced a significant increase in BBB permeability as measured with 14C-sucrose (Fig. 1), whereas the lower two doses were without effect. There was a significant decrease in the amount of 14C-sucrose in the serum (12.4 ± 3.9 % injection/ml to 8.4 ± 3.4 % injection/ml), indicating an increased leakage of peripheral capillary beds. In contrast to effects on BBB permeability, all doses of LPS produced a decrease in body weight (Fig. 2a). No dose of LPS had an effect on brain weight (Fig. 2b). The increase in 14C-sucrose was evident 24 h, but not 4 h, after a dose of 3 mg/kg of LPS (Fig. 2c). LPS also increased BBB permeability to albumin (Fig. 2d). The effect of LPS differed among brain regions (Table 1). Eight of 11 brain regions showed a statistically significant increase in BBB permeability to 14C-sucrose, but the hypothalamus, olfactory bulb, and occipital cortex had arithmetic increases that did not reach statistical significance (Table 1). All other studies used the three-injection regimen of LPS.Fig. 1


Lipopolysaccharide-induced blood-brain barrier disruption: roles of cyclooxygenase, oxidative stress, neuroinflammation, and elements of the neurovascular unit.

Banks WA, Gray AM, Erickson MA, Salameh TS, Damodarasamy M, Sheibani N, Meabon JS, Wing EE, Morofuji Y, Cook DG, Reed MJ - J Neuroinflammation (2015)

Dose-dependence of LPS on BBB permeability to 14C-Sucrose. Only the 3 mg/kg dose increased BBB permeability. **p < 0.01, n = 9/group
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4660627&req=5

Fig1: Dose-dependence of LPS on BBB permeability to 14C-Sucrose. Only the 3 mg/kg dose increased BBB permeability. **p < 0.01, n = 9/group
Mentions: Mice were studied 24 h after a single IP injection of LPS. The highest dose of LPS (3 mg/kg) administered to CD-1 mice produced a significant increase in BBB permeability as measured with 14C-sucrose (Fig. 1), whereas the lower two doses were without effect. There was a significant decrease in the amount of 14C-sucrose in the serum (12.4 ± 3.9 % injection/ml to 8.4 ± 3.4 % injection/ml), indicating an increased leakage of peripheral capillary beds. In contrast to effects on BBB permeability, all doses of LPS produced a decrease in body weight (Fig. 2a). No dose of LPS had an effect on brain weight (Fig. 2b). The increase in 14C-sucrose was evident 24 h, but not 4 h, after a dose of 3 mg/kg of LPS (Fig. 2c). LPS also increased BBB permeability to albumin (Fig. 2d). The effect of LPS differed among brain regions (Table 1). Eight of 11 brain regions showed a statistically significant increase in BBB permeability to 14C-sucrose, but the hypothalamus, olfactory bulb, and occipital cortex had arithmetic increases that did not reach statistical significance (Table 1). All other studies used the three-injection regimen of LPS.Fig. 1

Bottom Line: N-acetylcysteine did not affect disruption.In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

View Article: PubMed Central - PubMed

Affiliation: Geriatric Research Education and Clinical Center-VA Puget Sound Health Care System, Seattle, WA, USA. wabanks1@uw.edu.

ABSTRACT

Background: Disruption of the blood-brain barrier (BBB) occurs in many diseases and is often mediated by inflammatory and neuroimmune mechanisms. Inflammation is well established as a cause of BBB disruption, but many mechanistic questions remain.

Methods: We used lipopolysaccharide (LPS) to induce inflammation and BBB disruption in mice. BBB disruption was measured using (14)C-sucrose and radioactively labeled albumin. Brain cytokine responses were measured using multiplex technology and dependence on cyclooxygenase (COX) and oxidative stress determined by treatments with indomethacin and N-acetylcysteine. Astrocyte and microglia/macrophage responses were measured using brain immunohistochemistry. In vitro studies used Transwell cultures of primary brain endothelial cells co- or tri-cultured with astrocytes and pericytes to measure effects of LPS on transendothelial electrical resistance (TEER), cellular distribution of tight junction proteins, and permeability to (14)C-sucrose and radioactive albumin.

Results: In comparison to LPS-induced weight loss, the BBB was relatively resistant to LPS-induced disruption. Disruption occurred only with the highest dose of LPS and was most evident in the frontal cortex, thalamus, pons-medulla, and cerebellum with no disruption in the hypothalamus. The in vitro and in vivo patterns of LPS-induced disruption as measured with (14)C-sucrose, radioactive albumin, and TEER suggested involvement of both paracellular and transcytotic pathways. Disruption as measured with albumin and (14)C-sucrose, but not TEER, was blocked by indomethacin. N-acetylcysteine did not affect disruption. In vivo, the measures of neuroinflammation induced by LPS were mainly not reversed by indomethacin. In vitro, the effects on LPS and indomethacin were not altered when brain endothelial cells (BECs) were cultured with astrocytes or pericytes.

Conclusions: The BBB is relatively resistant to LPS-induced disruption with some brain regions more vulnerable than others. LPS-induced disruption appears is to be dependent on COX but not on oxidative stress. Based on in vivo and in vitro measures of neuroinflammation, it appears that astrocytes, microglia/macrophages, and pericytes play little role in the LPS-mediated disruption of the BBB.

No MeSH data available.


Related in: MedlinePlus