Role of natriuretic peptides in cGMP production in fetal cardiac bypass

Circulating histones for predicting prognosis after cardiac surgery: a prospective study

OBJECTIVES

The objective of this study was to assess the perioperative changes in circulating histones and their relationships with other biomarkers and clinical outcomes after cardiac surgery with cardiopulmonary bypass (CPB) in patients.

METHODS

Forty-eight patients with congenital cardiac diseases undergoing corrective procedure with CPB were prospectively enrolled in this study. Circulating histones, N-terminal pro-brain natriuretic peptide (NT-proBNP), procalcitonin (PCT) and C-reactive protein (CRP) were measured preoperatively (T0) and at 0 (T1), 24 (T2), 48 (T3) and 72 (T4) h postoperatively. The relationships between biomarkers and clinical outcomes were analysed.

RESULTS

Circulating histones, NT-proBNP, PCT and CRP increased significantly postoperatively, with histones reaching the peak value earliest at T1. Circulating histone levels were higher in patients with adverse events. Receiver operating characteristic curve analysis showed that peak histone levels had a better predictive value for adverse events postoperatively. Peak histone levels correlated with the peak level of NT-proBNP (r = 0.563, P < 0.01), PCT (r = 0.551, P < 0.01), CRP (r = 0.606, P < 0.01) and clinical parameters such as ventilation time (r = 0.601, P < 0.01) and intensive care unit time (r = 0.623, P < 0.01).

CONCLUSIONS

Circulating histones reached peak levels faster than NT-proBNP, PCT and CRP. Furthermore, peak histone levels correlated with biomarkers and postoperative clinical outcomes. Circulating histones may be used as a prognostic indicator for patients after cardiac surgery with CPB.

CLINICAL TRIALS

ClinicalTrials.gov (ID: NCT02325765).

Preoperative short-term parenteral administration of polyunsaturated fatty acids ameliorates intestinal inflammation and postoperative ileus in rodents

PURPOSE

Abdominal surgery results in an inflammation of the intestinal muscularis externa (ME), subsequently leading to postoperative ileus (POI). Polyunsaturated fatty acids (PUFA) are known to modulate inflammation. The aim of this study was to analyze the effect of preoperative parenteral administration of marine (n-3) or soybean (n-6) PUFA lipid emulsions (PUFA-LE) on POI and tissue fatty acid profiles.

METHODS

Rodents underwent intestinal manipulation (IM) after 5 days of parenteral administration of 10-mL/kg body weight saline, (n-3), or (n-6) PUFA-LE. Sham animals received saline treatment without IM. In rats, postoperative inflammation was quantified by ME neutrophil levels and NO production in organ culture, and ME function was determined by an in vitro contractility measurement. Additionally, in vivo gastrointestinal transit (GIT) was analyzed in mice. Lipopolysaccharide-induced IL-6 expression of rat bone marrow-derived mononuclear cells and ME was analyzed. Fatty acids were measured by gas chromatography in rat blood, bone marrow cells, and ME.

RESULTS

The (n-3) PUFA-LE reduced neutrophil levels and NO production after IM and improved in vitro jejunal contractility and GIT time. The (n-6) PUFA-LE significantly reduced postoperative inflammation and tended to improve intestinal motility (P < 0.06). Interestingly, (n-6) PUFA-LE significantly reduced the levels of arachidonic acid in ME (-63%), while (n-3) PUFA-LE reduced arachidonic acid (-20%) and additionally raised EPA (+550%).

CONCLUSION

Short-term preoperative parenteral administration of (n-3) or (n-6) PUFA-LE significantly alters tissue-specific fatty acid profiles. Preoperative parenteral PUFA-LE supplementation, preferably by marine (n-3) PUFA, ameliorates postoperative intestinal inflammation and dysmotility and could be a promising therapeutic option in POI prophylaxis.

Changes in fetal ovine metabolism and oxygen delivery with fetal bypass

Since the 1980s, attempts at experimental fetal cardiac bypass for the purpose of correcting severe congenital heart defects in the womb have been hampered by deterioration of placental function. This placental pathophysiology in turn affects transplacental transport of nutrients and gas exchange. To date, the effects of bypass on fetal metabolism and oxygen delivery have not been studied. Nine Suffolk sheep fetuses from 109-121 days gestation were instrumented and placed on fetal bypass for 30 min and followed postbypass for 2 h. Blood gases, glucose, and lactate were serially measured in the fetal arterial and umbilical venous circulations throughout the procedure. Insulin and glucagon levels were serially measured by immunoassay in fetal plasma. Fetal-placental hemodynamics were measured continuously. The expression of glycogen content was examined in fetal liver. Oxygen delivery to the fetus and fetal oxygen consumption were significantly deranged after the conduct of bypass (in-group ANOVA (P = 0.001) and overall contrast (P = 0.072) with planned contrast (P < 0.05) for delivery and consumption, respectively). There were significant alterations in fetal glucose metabolism in the postbypass period; however, insulin and glucagon levels did not change. Fetal liver glycogen content appeared lower after bypass. This is the first report documenting fetal metabolic dysregulation that occurs in response to the conduct of fetal bypass. The significant alterations in fetal oxygen and glucose delivery coupled with hepatic glycogen depletion complicate and impede fetal recovery. These initial findings warrant further investigation of interventions to restore metabolic and hemodynamic homeostasis after fetal bypass.