Regulation of protease activity

[Diagnostic value of granulocyte elastase determination in cord blood of newborn infants at risk for maternofetal infection]

BACKGROUND

Polymorphonuclear elastase is an early and sensitive indicator of neonatal infection when performed at the beginning of clinical symptoms.

PATIENTS AND METHODS

To investigate the diagnostic value of elastase measurement in cord blood immediately after birth, 211 neonates (103 boys vs 108 girls, 154 vaginal delivery vs 57 cesarean section). Mean gestational age 38.9 weeks (range: 30-42), mean birth weight 3,260 g (range: 1,430-4,920 g). After clinical, bacterial and biological screening, the infants were classified in three groups. Group A (n = 118): none infectious risk factor neither clinical signs of infection; group B (n = 79): one or more risk factors but no evidence of infection; group C (n = 14): proved or probable infection. Polymorphonuclear elastase was measured in cord blood of all infants using an heterogeneous enzyme-linked-immunosorbent assay.

RESULTS

We observed higher elastase values in group C (176 +/- 67 micrograms/L) than in group A (91 +/- 64 micrograms/L) and B (67 +/- 61 micrograms/L) (mean +/- SD, P = 0.0001). With a cutoff value fixed at 80 micrograms/L, the sensitivity of this test applicated to neonates presenting materno-fetal infectious risk factor(s) was 85% (12/14), specificity 74% (59/79), positive predictive value 37%, and negative predictive value 96%.

CONCLUSION

Because two of the 14 infected infants (15%) were not detected by elastase dosage in cord blood, this test cannot be used as an early indicator of materno-fetal infection.

Effects on peritoneal proteolysis and hemodynamics of prophylactic infusion with C1 inhibitor in experimental acute pancreatitis

Acute pancreatitis was induced in pigs by manual retrograde injection of Na-taurocholate into the pancreatic duct. Chromogenic peptide substrate assays showed increased trypsin (TRY) and plasma kallikrein activities (KK), parallel with a reduction of prekallikrein (PKK) levels and functional plasma kallikrein inhibition (KKI), in the peritoneal exudate in untreated animals. Pretreatment with C1 inhibitor (C1 INH) concentrate significantly increased the KKI capacity, parallel with unchanged KK and TRY activities in the peritoneal exudate. Furthermore, C1 INH pretreatment significantly improved the hemodynamic performance and the survival rate during a 6-h observation period. The study underlines the pathophysiological importance of trypsin and the plasma kallikrein-kinin system during acute pancreatitis. C1 INH concentrates given intravenously prevent activation of this system locally in the peritoneal exudate during experimental acute pancreatitis.