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Ischemic preconditioning does not prevent placental dysfunction induced by fetal cardiac bypass
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  • Renato Assad,
  • Marcelo G. A. Guedes,
  • Vera D. Aiello,
  • Petronio G. Thomaz,
  • Fernando L. Zanoni,
  • Mauricio Saito,
  • Ana Paula N. Da Silva,
  • Raphael dos S. Coutinho Silva E,
  • Marcelo Pinto,
  • Marcelo Jatene,
  • Luiz Felipe P. Moreira
Renato Assad
Universidade de Sao Paulo Instituto do Coracao

Corresponding Author:[email protected]

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Marcelo G. A. Guedes
Universidade de Sao Paulo Instituto do Coracao
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Vera D. Aiello
Universidade de Sao Paulo Instituto do Coracao
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Petronio G. Thomaz
Universidade de Sao Paulo Instituto do Coracao
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Fernando L. Zanoni
Universidade de Sao Paulo Instituto do Coracao
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Mauricio Saito
Universidade de Sao Paulo Instituto do Coracao
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Ana Paula N. Da Silva
Universidade de Sao Paulo Instituto do Coracao
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Raphael dos S. Coutinho Silva E
Universidade de Sao Paulo Instituto do Coracao
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Marcelo Pinto
Universidade de Sao Paulo Instituto do Coracao
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Marcelo Jatene
Universidade de Sao Paulo Instituto do Coracao
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Luiz Felipe P. Moreira
Universidade de Sao Paulo Instituto do Coracao
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Abstract

Background: Remote ischemic preconditioning (rIPC) has been applied to attenuate tissue injury. We tested the hypothesis that rIPC applied to fetal lambs undergoing cardiac bypass (CB) reduces fetal systemic inflammation and placental dysfunction. Methods: Eighteen fetal lambs were divided into 3 groups: sham, CB control, and CB rIPC. CB rIPC fetuses had a hindlimb tourniquet applied to occlude blood flow for 4 cycles of a 5-minute period, followed by a 2-minute reperfusion period. Both study groups underwent 30 minutes of normothermic CB. Fetal inflammatory markers, gas exchange, and placental and fetal lung morphological changes were assessed. Results: The CB rIPC group achieved higher bypass flow rates (p<.001). After CB start, both study groups developed significant decreases in PaO2, mixed acidosis and increased lactate levels (p<.0004). No significant differences on tissular edema were observed on fetal lungs and placenta (p>.391). Expression of toll-like receptor-4 and ICAM-1 in the placenta and fetal lungs did not differ among the 3 groups, as well as with VCAM-1 of fetal lungs (p>.225). Placental VCAM-1 expression was lower in the rIPC group (p<.05). Fetal interleukin-1 (IL-1) and thromboxane A2 (TXA2) levels were lower at 60 minutes post-CB in the CB rIPC group (p<.05). There was no significant differences in TNF-α, PGE2, IL-6 and IL-10 plasma levels of the three groups at 60-minute post-bypass (p>.133). Conclusion: Although rIPC allowed for increased blood flow during fetal CB and decreased in IL-1 and TXA2 levels and placental VCAM-1, it did not prevent placental dysfunction in fetal lambs undergoing CB.
12 May 2022Submitted to Journal of Cardiac Surgery
16 May 2022Assigned to Editor
16 May 2022Submission Checks Completed
05 Jun 2022Review(s) Completed, Editorial Evaluation Pending
05 Jun 2022Editorial Decision: Accept
Sep 2022Published in Journal of Cardiac Surgery volume 37 issue 9 on pages 2592-2599. 10.1111/jocs.16718