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Effect of repetitive asphyxia on leukocyte-vessel wall interactions in the developing chick intestine
E V Rouwet1, R J Beuk, E Heineman
1Department of Surgery, University Hospital Maastricht, The Netherlands.
Insights
Leukocyte-vessel wall interactions mature during fetal development. Asphyxia did not increase these interactions or cause intestinal damage in developing chick intestines, suggesting immaturity may contribute to necrotizing enterocolitis.
Area of Science:
- Developmental biology
- Gastroenterology
- Immunology
Background:
- Leukocyte-vessel wall interactions (LVWI) in the developing intestine are not well understood.
- Information on the maturation of these interactions during fetal development is scarce.
Purpose of the Study:
- To investigate leukocyte-vessel wall interactions (LVWI) in the developing chick intestine using intravital microscopy.
- To determine if asphyxia episodes increase LVWI and induce tissue damage in the immature intestine.
Main Methods:
- Developed an experimental model to study microcirculation in chick fetuses at different incubation stages (0.6, 0.7, 0.8).
- Induced asphyxia by clamping the chorioallantoic vein and recorded video before and after the procedure.
- Analyzed leukocyte rolling and adhesion under baseline and post-asphyxia conditions.
Main Results:
- Baseline leukocyte rolling significantly increased with incubation time (P < .001).
- Leukocyte adhesion was observed at 0.8 incubation but not earlier.
- Asphyxia did not enhance LVWI or cause histological damage in the developing intestine.
Conclusions:
- Leukocyte-vessel wall interactions mature progressively during fetal intestinal development.
- Repetitive asphyxia episodes do not trigger inflammatory responses or tissue injury in the developing intestine (0.6-0.8 incubation).
- Immature LVWI may contribute to necrotizing enterocolitis in premature neonates.
Background/Purpose:
Information on leukocyte-vessel wall interactions (LVWI) during development of the immature intestine is scarce. The authors designed an experimental model for studying the microcirculation in the developing intestine of chick fetuses at days 13 (n = 12), 15 (n = 17), and 17 (n = 19) of incubation (0.6, 0.7, and 0.8 of the incubation time, respectively) using intravital microscopy.
Methods:
The authors investigated whether episodes of asphyxia increase LVWI and induce tissue damage in the developing intestine. Asphyxia was induced by clamping of the chorioallantoic vein for 6 periods of 5 minutes each, with 5-minute intervals, whereas in sham groups a sham procedure was performed. Video recordings were made before as well as 10, 20, and 30 minutes after the end of the asphyxia or sham protocol.
Results:
Baseline number of rolling leukocytes per minute significantly increased (P < .001) from 0 at 0.6 incubation to 1.5 and to 4 at 0.7 and 0.8 incubation time, respectively. At 0.6 and 0.7 incubation no adherent leukocytes were observed under baseline conditions, whereas at 0.8 incubation single leukocytes adhered to the venular wall. LVWI variably increased during the course of the experiments. Asphyxia neither enhanced LVWI nor induced histological damage in the intestine.
Conclusions:
These findings indicate that (1) leukocyte-vessel wall interactions mature during fetal development, and (2) repetitive episodes of asphyxia induce neither an inflammatory response nor histological tissue injury in the developing intestine from 0.6 to 0.8 incubation. The authors hypothesize that immaturity of leukocyte-vessel wall interactions, as part of the nonspecific host defense to invading bacteria, might play a role in the development of necrotizing enterocolitis in premature neonates.