alpha1-Antitrypsin and alpha2-macroglobulin in newborn infants. I. The influence of perinatal complications

Metabolomic and proteomic analysis of serum from preterm infants with necrotising entercolitis and late-onset sepsis

BACKGROUND

Necrotising enterocolitis (NEC) and late-onset sepsis (LOS) are the leading causes of death among preterm infants in the developed world. This study aimed to explore the serum proteome and metabolome longitudinally in preterm infants with NEC or LOS, matched to controls.

METHODS

Nineteen patients (10 cases, 9 controls) were included. A sample 14 d prior to and following, as well as at disease diagnosis, was included for cases. Controls had serum matched at diagnosis for corresponding case. All samples (n = 39) underwent shotgun proteomic analysis, and 37 samples also underwent metabolomics analysis using ultra performance liquid chromatography-tandem mass spectrometry.

RESULTS

The proteomic and metabolomic profiles of serum were comparable between all infants. Eight proteins were associated with NEC and four proteins were associated with LOS. C-reactive protein was increased in all NEC patients at diagnosis.

CONCLUSION

No single protein or metabolite was detected in all NEC or LOS cases which was absent from controls; however, several proteins were identified which were associated with disease status. The differing expression of these proteins between diseased infants potentially relates to differing pathophysiology of disease. Thus, it is unlikely a single biomarker exists for NEC and/or LOS.

[Alpha 1-antitrypsin deficiency: a review with special reference to the significance of heterozygous deficiency]

Homozygous deficiency of alpha-1 antitrypsin is the most common inborn error or metabolism in Europe. Severe deficiency of this major protease inhibitor in serum is associated with chronic obstructive lung disease, chronic liver disease in adults and neonatal hepatitis. An overview is given of the role of heredity, and the diagnostic criteria and clinical and histological findings in this disorder. Emphysema seems to be caused by the free elastolytic activity of white cells, leading to the degradation of elastin. The pathophysiology of liver disease - less well understood - is discussed with special emphasis on the importance of heterozygous alpha-1 antitrypsin deficiency. Exogenous noxae seem to play an important role in the pathogenesis of heterozygous deficiency. In view of the 7% frequency of heterozygous alpha-1 antitrypsin deficiency in the European population and the role of noxae in the development of pulmonary and liver diseases, improved prophylaxis is mandatory.

Sequential determination of CRP, alpha 1-antitrypsin and haptoglobin in neonatal septicaemia

In 312 preterm and term newborn infants serum concentrations of C-reactive protein (CRP), haptoglobin and alpha 1-antitrypsin were measured during several days by radial immunodiffusion. In addition white blood cell count and the ratio of band to total neutrophils (B/N-ratio) were determined. In 12 infants with proven sepsis CRP was found elevated above the upper limit of the normal range (20 mg/l). Successful therapy was followed by a decrease of CRP concentration. In infants with suspected infection high CRP values were found in most cases. In contrast, haptoglobin and alpha 1-antitrypsin concentrations differed not significantly between the group of infants without infection, with proven and with suspected infection. White blood cell count and B/N-ratio also were not appropriate for the early identification of bacterial infection in the newborn period.

Transport of proteases across neonatal intestine and development of liver disease in infants with alpha-1 antitrypsin deficiency

The transport of macromolecules from the intestinal lumen into the systemic circulation is considerably greater in neonatal than in adult animals. Transport of both immunoglobin and non-immunoglobulin proteins is enhanced. It is postulated that luminal enzymes are also transported into the systemic circulation of the neonate and reach the liver. In the absence of protease inhibitors, such as occurs in alpha 1-antitrypsin (alpha 1-AT) deficiency, these intestinal enzymes may cause inflammation and, eventually, fibrosis of the liver. If this hypothesis is valid, treatment with trypsin inhibitors and elemental diets until the excessive macromolecular transport across the intestine ceases may help to prevent the liver disease associated with (alpha 1-AT) deficiency.