Dipeptidylpeptidase 4 (DPP4, CD26) activity in the blood serum of term and preterm neonates with cerebral ischemia.

Background: To investigate the mechanisms of inflammation in neonates after cerebral ischemia (CI), we evaluated the DPP4 activity in their blood sera and compared these values with clinical indicators.

Methods: The activity of DPP4 was determined in blood serum by a fluorescent method. We studied the correlation between the blood serum DPP4 activity and clinical, neurological and biochemical parameters in neonates with CI.

Results: No correlation between the DPP4 activity in umbilical blood and the venous blood of mothers was discovered. Increased blood serum DPP4 activity in full-term and pre-term newborns with CI is demonstrated. The interrelation between serum DPP4 activity and the functional disturbances of CNS (such as depression or excitement) was found in mature but not in premature newborns. Enzyme activity was still elevated at 2-3weeks after birth.

Conclusion: It is possible that in neonates this enzymatic system operates independently from mothers. It is assumed that increased DPP4 activity in newborns with CI is apparently connected with immune system activation in response to hypoxic stress. The obtained data support the participation of DPP4 in adaptive reactions of newborns and its regulating influence during hypoxemic damage of the CNS due to inflammation and neurodegeneration.