Exp. Clin Endocrinol. Vol. 95, No. 3, 1990, pp. 345-352
J. A. Barth, Leipzig
Central Institute of Diabetes "Gerhardt Katsch" (Director: OMR Prof. Dr. se. med. H. Bibergeil)', Department of Obstetrics and Gynecology (Director: Dr. se. med. H. Hopp), Karlsburg/GDR,
8 Clinic of Obstetrics and Gynecology (Director: Prof. Dr. se. med. H.-H. Buettner), Wismar/GDR
Circulating Levels of Placental Protein 10 (PP 10) in Diabetic Pregnancy Complicated by Retinopathy V. BRIESE1, D. G. SZABO2, E. GLÖCKNER1, R.-R. STRACHE3,
P. IIEINKE1, H. Hopp' and H.-H. BUETTNER3 With 3 Figures
Summary. Placental protein 10 (PP 10) is a soluble tissue antigen of the placenta. PP 10, a glycoprotein, was tested in diabetic pregnancy complicated by retinopathy. A continuous increase in PP 10 serum levels until weeks 35-36 is followed by a fall thereafter up to term. The mean of the healthy control group between 32 and 39 weeks gestation was 22 ± 10 gf I. In diabetic pregnancies complicated by retinopathy there were measured 69 ± 24 gfl in benign form and 77 ± 26 gfl in proliferative form. Both of these values are significantly (p < 0.05) above the control values. Increased PP 10 levels in diabetic pregnancy complicated by retinopathy are probably caused by placental and amniotic leakages.
Key words: Placental protein 10 (PP 10) - PP 10 serum levels in high risk pregnancies PP 10 in diabetic retinopathy
Introduction Several groups have made efforts to investigate the recently isolated placenta specific tissue proteins including placental protein 10 (PP 10) (Bohn and Kraus, 1979; Bohn, 1981; Than et al., 1983). PP 10 was recently found to be synthesized by the syn-
zytiotrophoblast of the placenta. PP 10 could be a suitable marker of the placental function in pregnancy (Inaba et al., 1980 a, b), the highest levels occuring between 32 and 36 weeks of pregnancy. Diabetic retinopathy is a proliferative complication of the microvascular system. It was assumed that the diabetic microvascular disease is also present in materno-fetal interface (Solerte et al., 1984). In our patients who showed evidence of retinopathy circulating levels of PP 10 were examined in orderto verify the diagnostic value in pregnancy.
Downloaded by: National University of Singapore. Copyrighted material.
2 Institute of Biochemistry, University Medical School (Director: Prof. Dr. Sc. med. H. Alkonyi), Pecs/Hungary, and
346
Exp. Clin. Endoerinol. 95 (1990) 3
Subjects and Methods Serum samples were collected from 36 insulin-dependent (IDDM) diabetic pregnant women (PP lo : loo serum samples from 36 women) who showed retinopathy complications (median age 23, ranged 18 to 33 years). They attended antenatal clinics between 8 and 39 weeks gestation and most of the diabetic patients in this group were primigravid. The subjects were assigned to risk classes according to the Priscilla White classification (White,
1965); 26 patients with benign (background) form of retinopathy, 8 patients with a proliferative retinopathy and 2 patients with a fulminant form of retinopathy. Retinopathy was evaluated by ophthalmoscopic examination. One patient had diabetic background retinopathy and diabetic neand assigned a centile (Kyank et aL, 1987). To obviate the remarkable diurnal variation in serum placental protein 10 levels, all the samples were collected at 8:00a.m. and stored at 20°C until tested. A healthy control group (17 to 38 years) was ranked according to standard deviations as well as 10th, 50th, and 90th percentiles from 420 healthy pregnants between 32 and 39 weeks gestation (published by Than et al., 1983). The distribution of gestational length and birth weights was normal. The PP 10 concentrations were measured by radioimmunoassay as described (Than. et a 1., 1983). A double antibody radioimmunoassay was performed. Highly purified PP 10 (Bohn, Ißehringwerke
AG, Marburg/Lahn, F.R.G.) was used for radioiodination and standardization. Radioiodination was carried out by lactoperoxidaseH2O2 (BoehringerfMannheim, F.R.G.) and followed by separating the labelled PP 10 from unreacted iodide by chromatography on a Sephadex G_100 column The standard curve for the assay was prepared using PP 10-concentrations (in triplicate) from 0.98 to 2SOng in 1 ml of 20mM PBS plus 2% bovine serum albumin (SIGMA). In RIA, 50 il of sample or standard and 200 l of rabbit anti-PP 10 antiserum (Bohn, Behringwerke AG, MarburgJLahn, F.R.G., diluted in 1:1000 from the 1:150000 stem solution) were preincubated for 5 h, then -200 zl of 125 J-Iabelled PP 10 (20000 cpm) were added and incubated for 24h at room temperature. Precipitation was done by adding 200 l of anti-rabbit gamma globulin goat serum "forte" (Behringwerke AG, Marburg/Lahn, F.R.G., Cat. No. OTOP 14/15, diluted 1:50), incubating at +4°C for 16 h, and centrifuging at 3000 g for 60 min. The supernatant was aspirated, the precipitates were washed with 1 ml assay buffer and counted for radioactivity. All samples were tested in duplicates and without dilution. The sensitivtiy of the assay was 1 intraassay coefficient of variation
J. A. Barth, Leipzig
Central Institute of Diabetes "Gerhardt Katsch" (Director: OMR Prof. Dr. se. med. H. Bibergeil)', Department of Obstetrics and Gynecology (Director: Dr. se. med. H. Hopp), Karlsburg/GDR,
8 Clinic of Obstetrics and Gynecology (Director: Prof. Dr. se. med. H.-H. Buettner), Wismar/GDR
Circulating Levels of Placental Protein 10 (PP 10) in Diabetic Pregnancy Complicated by Retinopathy V. BRIESE1, D. G. SZABO2, E. GLÖCKNER1, R.-R. STRACHE3,
P. IIEINKE1, H. Hopp' and H.-H. BUETTNER3 With 3 Figures
Summary. Placental protein 10 (PP 10) is a soluble tissue antigen of the placenta. PP 10, a glycoprotein, was tested in diabetic pregnancy complicated by retinopathy. A continuous increase in PP 10 serum levels until weeks 35-36 is followed by a fall thereafter up to term. The mean of the healthy control group between 32 and 39 weeks gestation was 22 ± 10 gf I. In diabetic pregnancies complicated by retinopathy there were measured 69 ± 24 gfl in benign form and 77 ± 26 gfl in proliferative form. Both of these values are significantly (p < 0.05) above the control values. Increased PP 10 levels in diabetic pregnancy complicated by retinopathy are probably caused by placental and amniotic leakages.
Key words: Placental protein 10 (PP 10) - PP 10 serum levels in high risk pregnancies PP 10 in diabetic retinopathy
Introduction Several groups have made efforts to investigate the recently isolated placenta specific tissue proteins including placental protein 10 (PP 10) (Bohn and Kraus, 1979; Bohn, 1981; Than et al., 1983). PP 10 was recently found to be synthesized by the syn-
zytiotrophoblast of the placenta. PP 10 could be a suitable marker of the placental function in pregnancy (Inaba et al., 1980 a, b), the highest levels occuring between 32 and 36 weeks of pregnancy. Diabetic retinopathy is a proliferative complication of the microvascular system. It was assumed that the diabetic microvascular disease is also present in materno-fetal interface (Solerte et al., 1984). In our patients who showed evidence of retinopathy circulating levels of PP 10 were examined in orderto verify the diagnostic value in pregnancy.
Downloaded by: National University of Singapore. Copyrighted material.
2 Institute of Biochemistry, University Medical School (Director: Prof. Dr. Sc. med. H. Alkonyi), Pecs/Hungary, and
346
Exp. Clin. Endoerinol. 95 (1990) 3
Subjects and Methods Serum samples were collected from 36 insulin-dependent (IDDM) diabetic pregnant women (PP lo : loo serum samples from 36 women) who showed retinopathy complications (median age 23, ranged 18 to 33 years). They attended antenatal clinics between 8 and 39 weeks gestation and most of the diabetic patients in this group were primigravid. The subjects were assigned to risk classes according to the Priscilla White classification (White,
1965); 26 patients with benign (background) form of retinopathy, 8 patients with a proliferative retinopathy and 2 patients with a fulminant form of retinopathy. Retinopathy was evaluated by ophthalmoscopic examination. One patient had diabetic background retinopathy and diabetic neand assigned a centile (Kyank et aL, 1987). To obviate the remarkable diurnal variation in serum placental protein 10 levels, all the samples were collected at 8:00a.m. and stored at 20°C until tested. A healthy control group (17 to 38 years) was ranked according to standard deviations as well as 10th, 50th, and 90th percentiles from 420 healthy pregnants between 32 and 39 weeks gestation (published by Than et al., 1983). The distribution of gestational length and birth weights was normal. The PP 10 concentrations were measured by radioimmunoassay as described (Than. et a 1., 1983). A double antibody radioimmunoassay was performed. Highly purified PP 10 (Bohn, Ißehringwerke
AG, Marburg/Lahn, F.R.G.) was used for radioiodination and standardization. Radioiodination was carried out by lactoperoxidaseH2O2 (BoehringerfMannheim, F.R.G.) and followed by separating the labelled PP 10 from unreacted iodide by chromatography on a Sephadex G_100 column The standard curve for the assay was prepared using PP 10-concentrations (in triplicate) from 0.98 to 2SOng in 1 ml of 20mM PBS plus 2% bovine serum albumin (SIGMA). In RIA, 50 il of sample or standard and 200 l of rabbit anti-PP 10 antiserum (Bohn, Behringwerke AG, MarburgJLahn, F.R.G., diluted in 1:1000 from the 1:150000 stem solution) were preincubated for 5 h, then -200 zl of 125 J-Iabelled PP 10 (20000 cpm) were added and incubated for 24h at room temperature. Precipitation was done by adding 200 l of anti-rabbit gamma globulin goat serum "forte" (Behringwerke AG, Marburg/Lahn, F.R.G., Cat. No. OTOP 14/15, diluted 1:50), incubating at +4°C for 16 h, and centrifuging at 3000 g for 60 min. The supernatant was aspirated, the precipitates were washed with 1 ml assay buffer and counted for radioactivity. All samples were tested in duplicates and without dilution. The sensitivtiy of the assay was 1 intraassay coefficient of variation
