Britishlournal of Haematoloxy, 1979,42,567-574.
Neonatal Erythrocyte Glutathione Peroxidase Deficiency as a Consequence of Selenium Imbalance during Pregnancy G. PERONA, G. C. GUIDI,A. PIGA,R. CELLERINO, G. MILANI,P. COLAWI-TI,* G. MOSCHINI* AND B. M. STIEVANO*
Section of Haematology, Istituto di Patologia Medica II, Division of Clinical Chemistry and Clinica Ostetrica II, University of Padova (Verona), and *Laboratori Nazionali dell'lNFN, University of Padova (Legnaro) (Received 9 M a y 1978; accepted f o r publication 12 December 1978) SUMMARY. The red blood cell (RBC) glutathione peroxidase (GSH-Px) activity and routine haematological parameters were measured in 38 healthy north Italian full-term pregnant women and in their newborn infants. In 31 pairs the serum selenium concentration was also measured. Data were compared with those of 20 normal adult controls (10 males and 10 females). Newborn infants exhibited significantly lower RBC GSH-Px activity and serum selenium concentrations than adult controls. Pregnant women had serum selenium values intermediate between those of adult female controls and their newborn infants. In both the pregnant women and newborns the RBC GSH-Px activity correlated with the level of selenium in serum which suggests that the neonatal RBC GSH-Px deficiency may be partially due to insufficient availability of selenium during pregnancy. Factors other than selenium concentration, e.g. hormonal and genetic, might also affect the RBC GSH-Px activity as suggested by sex differences and mother/child concordances in enzyme activity found in our cases. In recent years, data relating to human erythrocyte glutathione perioxidase (GSH-Px) has accumulated. Clinical interest arises from the critical role played by GSH-Px in preventing biological damage due to peroxide accumulation, and from the possibility that an impairment of this enzyme can cause spontaneous or drug-induced haemolysis. An unexplained 'physiological' GSH-Px deficiency has been observed in normal newborn infants which might explain the increased susceptibility of their RBC to oxidative haemolysis (Gross et all 1967; Bracci et all 1969; Necheles et al, 1970; Boivin et all 1971; Emerson et al, 1972; Luang Eng et al, 1973). Necheles et a1 (1970) reported 11 cases of neonatal jaundice with RBC GSH-Px activity Correspondence: Professor Giuseppe Perona, Istituto di Patologia Medica, Policlinico di Borgo Roma, 37100 Verona, Italy. 0007-1048/79/0800-0567$02.00
0 1979 Blackwell Scientific Publications 567
568
G. Perona et a1
ranging from 28% to 59% of the adult mean normal value. O n the basis of family studies, the authors hypothesized that these infants had a genetically-determined partial GSH-Px deficiency. However, FlohC et al (1973) demonstrated that GSH-Px is a selenoenzyme and a significantly positive correlation between serum selenium concentration and RBC GSH-Px has been observed in a group of 14 adult patients (Perona et al, 1977). It was also found that the addition of selenium stimulates, both in vivo and in vitro, the GSH-Px activity in normal human RBC (Perona et al, 1978). In this paper we present the results of our investigations on factors affecting the RBC GSH-Px activity in a group of newborn infants and their mothers. MATERIALS A N D METHODS Patients Thirty-eight normal full-term pregnant women and their newborn sons have been examined. They were selected only on the basis of ABO and Rh compatibility and absence of isoimmune sensitization. Most of the women, aged from 19 to 39, had received oral iron during pregnancy. A t delivery, mothers’ venous blood and cord blood samples were collected for examination. Haematological examinations were repeated in those infants who developed neonatal jaundice. Twenty normal adults (10 males and 10 females) aged from 16 to 59 were used as controls. RBC GSH-Px activity was measured using a modification of the method reported by Beutler (1971), in which the enzyme activity is indirectly determined by measuring the coupled oxidation of NADPH. Tert butyl-hydroperoxide was used as acceptor substrate instead of H z 0 2as suggested by Gunzler et al (1974) and the reaction followed at 25°C in a Unicam recording spectrophotometer. Enzyme activity is expressed as pmoles of NADPH oxidized/min/g of H b (u/g Hb), (Perona et al, 1978). The serum selenium concentration was measured by a proton-induced X-ray fluorescence technique as previously reported (Berti et al, 1977; Perona et al, 1977). The 2 MeV Van Der Graaf accelerator of ‘Laboratori Nazionali di Legnaro’ was used as the proton source and X-rays were detected by a Si (Li) detector. Palladium was used as the internal standard for quantitative selenium determinations with an overall sensitivity of 10 parts per billion and a reproducibility of f 10%. Results have been expressed as pg of selenium/1000 ml of serum. Statistical analysis was performed by the Student’s t test and by the r correlation test. Differences between mothers and infants were tested by paired t statistics. Means are expressed as +1 SD.
RESULTS Erythrocyte GSH-Px (Table I) The mean GSH-Px activity was significantly lower in adult males than in female controls. Pregnant women exhibited a slightly reduced enzyme activity as compared with the female controls, but this was not statistically significant. The enzyme activity of the newborn infants was significantly lower than that of both pregnant women and adult controls; moreover they exhibited a significant sex difference in this regard. Fig 1 shows that some pregnant women and many newborn infants had a GSH-Px activity of less than half the adult control value.
Neonatal Erythrocyte Glutathione Peroxidase Dejciency
569
TABLE I
Body wekht Pregnant women (38) Newborns (38) Male newborns (25) Female newborns (13)
Hb (gldl)
11.98k1.02 3.54k0.43 14.70+ 1.47 3.53k0.35 14.72k 1.47 3.56k0.55 14.68k 1.53
Serum bilirubin (WlU
Serum Se
(MI0
RBC G S H - P x (ulg H b )
4.1k1.7 15.4k5.1 16.0k5.2 14.4k5.0
51.37k8.50. 38.83+7+30* 35.87k5.32144.20+8.92$ 75.29+ 19.87 74.78k24.20 7540k 15.7
3.72k1.18 2 3 3 k 1.06 2.57k0.94 3.33k1.14 3.56 k 047 2.95k0.68 4.16k0.56
n.s.
P< 0.001
P
Neonatal Erythrocyte Glutathione Peroxidase Deficiency as a Consequence of Selenium Imbalance during Pregnancy G. PERONA, G. C. GUIDI,A. PIGA,R. CELLERINO, G. MILANI,P. COLAWI-TI,* G. MOSCHINI* AND B. M. STIEVANO*
Section of Haematology, Istituto di Patologia Medica II, Division of Clinical Chemistry and Clinica Ostetrica II, University of Padova (Verona), and *Laboratori Nazionali dell'lNFN, University of Padova (Legnaro) (Received 9 M a y 1978; accepted f o r publication 12 December 1978) SUMMARY. The red blood cell (RBC) glutathione peroxidase (GSH-Px) activity and routine haematological parameters were measured in 38 healthy north Italian full-term pregnant women and in their newborn infants. In 31 pairs the serum selenium concentration was also measured. Data were compared with those of 20 normal adult controls (10 males and 10 females). Newborn infants exhibited significantly lower RBC GSH-Px activity and serum selenium concentrations than adult controls. Pregnant women had serum selenium values intermediate between those of adult female controls and their newborn infants. In both the pregnant women and newborns the RBC GSH-Px activity correlated with the level of selenium in serum which suggests that the neonatal RBC GSH-Px deficiency may be partially due to insufficient availability of selenium during pregnancy. Factors other than selenium concentration, e.g. hormonal and genetic, might also affect the RBC GSH-Px activity as suggested by sex differences and mother/child concordances in enzyme activity found in our cases. In recent years, data relating to human erythrocyte glutathione perioxidase (GSH-Px) has accumulated. Clinical interest arises from the critical role played by GSH-Px in preventing biological damage due to peroxide accumulation, and from the possibility that an impairment of this enzyme can cause spontaneous or drug-induced haemolysis. An unexplained 'physiological' GSH-Px deficiency has been observed in normal newborn infants which might explain the increased susceptibility of their RBC to oxidative haemolysis (Gross et all 1967; Bracci et all 1969; Necheles et al, 1970; Boivin et all 1971; Emerson et al, 1972; Luang Eng et al, 1973). Necheles et a1 (1970) reported 11 cases of neonatal jaundice with RBC GSH-Px activity Correspondence: Professor Giuseppe Perona, Istituto di Patologia Medica, Policlinico di Borgo Roma, 37100 Verona, Italy. 0007-1048/79/0800-0567$02.00
0 1979 Blackwell Scientific Publications 567
568
G. Perona et a1
ranging from 28% to 59% of the adult mean normal value. O n the basis of family studies, the authors hypothesized that these infants had a genetically-determined partial GSH-Px deficiency. However, FlohC et al (1973) demonstrated that GSH-Px is a selenoenzyme and a significantly positive correlation between serum selenium concentration and RBC GSH-Px has been observed in a group of 14 adult patients (Perona et al, 1977). It was also found that the addition of selenium stimulates, both in vivo and in vitro, the GSH-Px activity in normal human RBC (Perona et al, 1978). In this paper we present the results of our investigations on factors affecting the RBC GSH-Px activity in a group of newborn infants and their mothers. MATERIALS A N D METHODS Patients Thirty-eight normal full-term pregnant women and their newborn sons have been examined. They were selected only on the basis of ABO and Rh compatibility and absence of isoimmune sensitization. Most of the women, aged from 19 to 39, had received oral iron during pregnancy. A t delivery, mothers’ venous blood and cord blood samples were collected for examination. Haematological examinations were repeated in those infants who developed neonatal jaundice. Twenty normal adults (10 males and 10 females) aged from 16 to 59 were used as controls. RBC GSH-Px activity was measured using a modification of the method reported by Beutler (1971), in which the enzyme activity is indirectly determined by measuring the coupled oxidation of NADPH. Tert butyl-hydroperoxide was used as acceptor substrate instead of H z 0 2as suggested by Gunzler et al (1974) and the reaction followed at 25°C in a Unicam recording spectrophotometer. Enzyme activity is expressed as pmoles of NADPH oxidized/min/g of H b (u/g Hb), (Perona et al, 1978). The serum selenium concentration was measured by a proton-induced X-ray fluorescence technique as previously reported (Berti et al, 1977; Perona et al, 1977). The 2 MeV Van Der Graaf accelerator of ‘Laboratori Nazionali di Legnaro’ was used as the proton source and X-rays were detected by a Si (Li) detector. Palladium was used as the internal standard for quantitative selenium determinations with an overall sensitivity of 10 parts per billion and a reproducibility of f 10%. Results have been expressed as pg of selenium/1000 ml of serum. Statistical analysis was performed by the Student’s t test and by the r correlation test. Differences between mothers and infants were tested by paired t statistics. Means are expressed as +1 SD.
RESULTS Erythrocyte GSH-Px (Table I) The mean GSH-Px activity was significantly lower in adult males than in female controls. Pregnant women exhibited a slightly reduced enzyme activity as compared with the female controls, but this was not statistically significant. The enzyme activity of the newborn infants was significantly lower than that of both pregnant women and adult controls; moreover they exhibited a significant sex difference in this regard. Fig 1 shows that some pregnant women and many newborn infants had a GSH-Px activity of less than half the adult control value.
Neonatal Erythrocyte Glutathione Peroxidase Dejciency
569
TABLE I
Body wekht Pregnant women (38) Newborns (38) Male newborns (25) Female newborns (13)
Hb (gldl)
11.98k1.02 3.54k0.43 14.70+ 1.47 3.53k0.35 14.72k 1.47 3.56k0.55 14.68k 1.53
Serum bilirubin (WlU
Serum Se
(MI0
RBC G S H - P x (ulg H b )
4.1k1.7 15.4k5.1 16.0k5.2 14.4k5.0
51.37k8.50. 38.83+7+30* 35.87k5.32144.20+8.92$ 75.29+ 19.87 74.78k24.20 7540k 15.7
3.72k1.18 2 3 3 k 1.06 2.57k0.94 3.33k1.14 3.56 k 047 2.95k0.68 4.16k0.56
n.s.
P< 0.001
P
