TY - JOUR
T1 - Polymorphonuclear leukocytes released from the bone marrow preferentially sequester in-lung micro vessels
AU - Van Eeden, Stephan F.
AU - Kitagawa, Yuko
AU - Klut, Maria E.
AU - Lawrence, Elizabeth
AU - Hogg, James C.
PY - 1997/9
Y1 - 1997/9
N2 - Objective: A hallmark of the systemic response to an inflammatory stimulus is the release of polymorphonuclear leukocytes (PMNs) from the bone marrow. This study was designed to measure the release of PMNs from the bone marrow and to determine their sequestration in the lung after an intravenous injection of either endotoxin (n = 5) or saline (n = 5). Methods and Results: The thymidine analogue 5′-bromo-2-deoxyuridine (BrdU) was used to pulse label dividing PMNs in the bone marrow of rabbits (n = 13), and immunohistochemistry and morphometry were used to detect the release of BrdU-labeled PMNs into the circulation and to determine their sequestration in the lung. Endotoxin treatment caused a drop in the circulating PMN counts (3.3 ± 0.08 at baseline to 0.12 ± 0.02 × 109/L at 1 hour after endotoxin), which was followed by a neutrophilia at 8 hours (6.3 ± 1.1 × 109/L, p < 0.01), an increase in circulating band cells (0.12 ± 0.01 at baseline to 2.18 ± 0.4 × 19/L at 8 hours, p < 0.001), and an increase in the percentage of BrdU-labeled PMNs (0.01% ± 0.004% at baseline to 26.1% ± 3.2% at 8 hours, p < 0.001). Endotoxemia caused an arteriovenous difference in BrdU-labeled PMNs across the lung (35.9% ± 2.9% versus 26.1% ± 3.1%, mixed venous versus arterial, p < 0.02). Morphometric studies showed that endotoxin caused sequestration of PMNs in the lung (2.2 ± 0.4 versus 1.0 ± 0.2 × 1010, endotoxin versus saline, p < 0.03) with preferential retention of BrdU-labeled PMNs (0.79 ± 0.21 versus 0.039 ± 0.016 × 1010, endotoxin versus saline, p < 0.05). The percentage of BrdU-labeled PMNs in the alveolocapillary walls was higher than in circulating blood (64.01% ± 4.3% versus 26.1% ± 3.2%, p < 0.01) in the endotoxin group. In vitro filtration of cells through 5-mm pore size filters showed that circulating BrdU-labeled PMNs, 8 hours after endotoxin, were preferentially retained in the filters (p < 0.01). Conclusions: We conclude that endotoxemia stimulates the bone marrow to release mature and immature PMNs. Compared to PMNs released from the bone marrow during normal turnover, these PMNs are less deformable and preferentially sequester in the lung microvessels.
AB - Objective: A hallmark of the systemic response to an inflammatory stimulus is the release of polymorphonuclear leukocytes (PMNs) from the bone marrow. This study was designed to measure the release of PMNs from the bone marrow and to determine their sequestration in the lung after an intravenous injection of either endotoxin (n = 5) or saline (n = 5). Methods and Results: The thymidine analogue 5′-bromo-2-deoxyuridine (BrdU) was used to pulse label dividing PMNs in the bone marrow of rabbits (n = 13), and immunohistochemistry and morphometry were used to detect the release of BrdU-labeled PMNs into the circulation and to determine their sequestration in the lung. Endotoxin treatment caused a drop in the circulating PMN counts (3.3 ± 0.08 at baseline to 0.12 ± 0.02 × 109/L at 1 hour after endotoxin), which was followed by a neutrophilia at 8 hours (6.3 ± 1.1 × 109/L, p < 0.01), an increase in circulating band cells (0.12 ± 0.01 at baseline to 2.18 ± 0.4 × 19/L at 8 hours, p < 0.001), and an increase in the percentage of BrdU-labeled PMNs (0.01% ± 0.004% at baseline to 26.1% ± 3.2% at 8 hours, p < 0.001). Endotoxemia caused an arteriovenous difference in BrdU-labeled PMNs across the lung (35.9% ± 2.9% versus 26.1% ± 3.1%, mixed venous versus arterial, p < 0.02). Morphometric studies showed that endotoxin caused sequestration of PMNs in the lung (2.2 ± 0.4 versus 1.0 ± 0.2 × 1010, endotoxin versus saline, p < 0.03) with preferential retention of BrdU-labeled PMNs (0.79 ± 0.21 versus 0.039 ± 0.016 × 1010, endotoxin versus saline, p < 0.05). The percentage of BrdU-labeled PMNs in the alveolocapillary walls was higher than in circulating blood (64.01% ± 4.3% versus 26.1% ± 3.2%, p < 0.01) in the endotoxin group. In vitro filtration of cells through 5-mm pore size filters showed that circulating BrdU-labeled PMNs, 8 hours after endotoxin, were preferentially retained in the filters (p < 0.01). Conclusions: We conclude that endotoxemia stimulates the bone marrow to release mature and immature PMNs. Compared to PMNs released from the bone marrow during normal turnover, these PMNs are less deformable and preferentially sequester in the lung microvessels.
KW - Acute lung injury
KW - Endotoxin
KW - L-selectin
KW - Polymorphonuclear leukocytes
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U2 - 10.3109/10739689709146801
DO - 10.3109/10739689709146801
M3 - Review article
C2 - 9329013
AN - SCOPUS:0031227757
VL - 4
SP - 369
EP - 380
JO - Microcirculation
JF - Microcirculation
SN - 1073-9688
IS - 3
ER -