Embryonic fatty acid metabolism in diabetic pregnancy: the difference between embryoblasts and trophoblasts.

During the first days of development the preimplantation embryo is supplied with nutrients from the surrounding milieu. Maternal diabetes mellitus affects the uterine microenvironment, leading to a metabolic adaptation processes in the embryo. We analysed embryonic fatty acid (FA) profiles and expression of processing genes in rabbit blastocysts, separately in embryoblasts (EBs) and trophoblasts (TBs), to determine the potential consequences of maternal diabetes mellitus on intracellular FA metabolism. Insulin-dependent diabetes was induced by alloxan in female rabbits. On Day 6 post coitum, FA profiles in blastocysts (EB, TB and blastocoel fluid) and maternal blood were analysed by gas chromatography. The expression levels of molecules involved in FA elongation (fatty acid elongases, ELOVLs) and desaturation (fatty acid desaturases, FADSs) were measured in EB and TB. Maternal diabetes mellitus influenced the FA profile in maternal plasma and blastocysts. Independent from metabolic changes, rabbit blastocysts contained a higher level of saturated fatty acids (SFAs) and a lower level of polyunsaturated fatty acids (PUFAs) compared to the FA profile of the maternal plasma. Furthermore, the FA profile was altered in the EB and TB, differently. While SFAs (palmitic and stearic acid) were elevated in EB of diabetic rabbits, PUFAs, such as docosahexaenoic acid, were decreased. In contrast, in the TB, lower levels of SFAs and higher levels of oleic acid were observed. EB and TB specific alterations in gene expression were found for ELOVLs and FADSs, key enzymes for FA elongation and desaturation. In conclusion, maternal diabetes mellitus alters embryonic FA metabolism differently in EB and TB, indicating a lineage-specific metabolic adaptive response.

Improvement of fertility with adoptive CD25+ natural killer cell transfer in subfertile non-obese diabetic mice.

To investigate the role that CD25(+) natural killer (NK) cells may play in the establishment of pregnancy, the effect of adoptive CD25(+) NK cell transfer on pregnancy outcome in subfertile non-obese diabetic (NOD) mice was investigated. Phenotypic analysis of NK cells was performed by flow cytometry before and after the transfer. The proportion of subfertile NOD female mice that failed to become pregnant when co-caged with C57Bl/6 males for 16 weeks was significantly higher in female NOD mice than in normal female BALB/c controls (53.1% versus 15.1%; P < 0.01). The subfertile NOD mice were divided into three groups receiving CD25(+) NK cells (group 1), CD25(-) cells (group 2) or RPMI 1640 medium only (group 3). Group 1 had significantly more pregnancies than those receiving CD25(-) NK cells (77.8% versus 11.1%; P < 0.01) and controls injected with RPMI 1640 medium (0.0%; P < 0.01). Improved fertility was concomitant with an increase in placental CD49b(+) NK cells expressing Foxp3. Foxp3 expression was confirmed in the CD25(+) NK cells before the transfer. These results indicate that subfertility in NOD mice may be partially attributed to the insufficiency of CD25(+) and Foxp3(+) NK cells recruited into the pregnant uterus.

Folic acid prevents congenital malformations in the offspring of diabetic mice.

It is well known that maternal diabetes causes various congenital malformations. Although there are many reports that folic acid (FA) administration in pregnancy reduces the risk of birth defects including neural tube defects (NTDs), a precise analysis on the preventive effect of FA against diabetic embryopathy has not been done yet. In this study, we analyzed the preventive effects of FA on congenital malformations including NTDs, cardiovascular, and skeletal malformations using a diabetic mouse model. Female mice were rendered hyperglycemic by streptozotocin and then mated. Pregnant diabetic mice were treated daily with FA (3 mg/kg body weight) or saline between gestational days (GD) 6 and 10. On GD 18, fetuses were examined for congenital malformations. FA did not affect plasma glucose levels. In the DM control group, the incidence of NTDs, cardiovascular, and skeletal malformations was 28.4%, 28.5%, and 29.7%, respectively. In the FA-treated group, the corresponding proportions reduced to 6.0%, 2.5% and 12.5%, respectively. A whole-mount TUNEL revealed an increased apoptosis in the hindbrain region of embryos from DM control group on day 9.5, and the apoptosis was decreased by FA treatment. Maternal plasma homocysteine levels on GD 9.5 were significantly lowered in DM control group compared with those in non-DM group, and FA treatment did not show a significant effect. These results indicate that FA is effective for the prevention of various diabetic embryopathy including NTDs, cardiovascular, and skeletal malformations, and suggested that this effect is independent from homocysteine metabolism and possibly mediated by decreasing the abnormal apoptosis during organogenesis.

The onset of maternal diabetes in swine induces alterations in the development of the fetal preadipocyte.

Diabetes induced during gestation has previously been demonstrated to increase adipose accretion in the fetal pig. The present experiment examined whether maternal diabetes alters the proliferation and differentiation of the fetal preadipocyte. Seven crossbred gilts were injected with alloxan (50 mg/kg) at d 75 of gestation to induce diabetes and seven additional gilts were injected with buffer (controls). All gilts underwent Caesarean section of d 105 of gestation. Cells obtained from adipose tissue of fetuses of diabetic swine (FDS) at d 105 of gestation demonstrated a greater (P < .05) proliferative response (57%) and higher (P < .05) rates of differentiation as determined by sn-glycerol-3-phosphate dehydrogenase (142% increase) and lipoprotein lipase (80% increase) activities than cells acquired from fetuses of control swine (FCS). Adipogenic activity of the sera from these two groups of fetuses did not differ when tested on adipose tissue from fetuses at 105 d of gestation. However, use of these sera on cells derived from normal fetuses at 75 d of gestation resulted in detection of an increase (P < .05) in adipogenic activity within the sera from FDS. This study suggests that maternal diabetes causes alterations in the preadipocyte fraction of cells within the developing adipose tissue that result in formation of more adipocytes and thus permits greater capacity for lipid accumulation in the growing fetus of the diabetic pig. These alterations in the preadipocyte result from the activity of factors that transitionally function during the latter half of gestation.

In vitro microdialysis of the ovine corpus luteum of pregnancy: effects of insulin-like growth factor on progesterone secretion.

The effects of insulin-like growth factor-1 (IGF-1) and cAMP on progesterone (P) secretion by CL of streptozotocin-induced-diabetic pregnant ewes were compared with the effects on normal pregnant animals. Two types of CL were identified in the ovaries removed on Days 126.6 +/- 2 of pregnancy. They were either large, reddish in color, and vascular (type A) or small and pale yellow (type B). Both types were found in diabetic and normal sheep. Each CL was divided in two and perfused in parallel for 14 h in an in vitro microdialysis-perifusion system. One half was used to evaluate basal P secretion and the effect of cAMP. The effect of IGF-1 and cAMP infusion was studied in the other half. During microdialysis, fractions were collected every 15 min, and P was determined by RIA. IGF-1 stimulated secretion of P in the large type A, normal and diabetic sheep CL in discrete pulses. The smaller CL (type B) from normal sheep produced comparatively higher levels of P in discrete pulses in the presence of IGF-1. However, the small CL from diabetic sheep showed no response to IGF-1 or cAMP, and P secretion was lower. Thus, it is probable that the large CL may be the "active" CL producing P and that IGF-1 stimulates pulsatile P secretion in such CL from both normal and diabetic pregnant sheep.

Effect of hyperadrenocorticism and diabetes mellitus on serum progesterone concentrations during early metoestrus of pregnant and non-pregnant cycles induced by pregnant mares' serum gonadotrophin in domestic dogs.

The intramuscular (i.m.) administration of pregnant mares' serum gonadotrophin (PMSG) (20 iu kg-1 day-1 for 5 days) followed by an injection of human chorionic gonadotrophin (500 iu, i.m.) induced oestrus in 28 cross-bred bitches. These included, based on endocrine evaluations, nine normal (N), seven insulin-deficient diabetic (ID), six insulin-resistant (IR) and six hypercortisolic (HC) bitches. The bitches were not bred but were allowed to have a non-pregnant cycle. When oestrus was induced a second time by re-treating at 35 days after the end of the non-pregnant metoestrus of the first induced cycle, the dogs were mated. Pregnancy was obtained in five N, four ID, four IR and three HC dogs; 15 of the 16 dogs had litters. For these 16 dogs, progesterone concentrations in serum were evaluated from samples that had been obtained daily during the first 30 days of the first (non-pregnant) induced cycle and the first 11 days of metoestrus of the second induced (pregnant) cycle. Corpus luteum development was characterized in normal bitches by a steady increase in progesterone, with highest values (33 +/- 6 ng ml-1) at day 8 of metoestrus in pregnant dogs. Progesterone averaged among the first 11 days of metoestrus (pregnant and non-pregnant) did not differ between normal and insulin-resistant bitches (20 +/- 5 versus 22 +/- 4 ng ml-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological and pathological influences on sheep blood plasma amine oxidase: effect of pregnancy and experimental alloxan-induced diabetes mellitus.

A copper-containing amine oxidase is present in sheep blood plasma and has a high capacity to deaminate spermine and spermidine. The physiological function of this enzyme remains to be determined. Sheep blood plasma amine oxidase (SPAO) was measured by its ability to deaminate spermidine (700 microM) using a peroxidase-linked colorimetric assay developed for microtitre plates. SPAO activity has been studied in a group of Welsh Mountain sheep with experimental alloxan-induced diabetes. This resulted in an increase in SPAO activity which reached a peak of 70 days after alloxan treatment (60 per cent increase). This change could be seen in both pregnant and non-pregnant diabetic sheep. In normal pregnant ewes, SPAO activity remained stable for the first 100 days of pregnancy but declined by 50 per cent in the last month of pregnancy. Together, these findings suggest that SPAO activity is controlled by hormonal influences. This sensitive and convenient assay method could provide clues as to the physiological significance of SPAO and may be a useful clinical chemical indicator in the sheep.

Alloxan-induced diabetes mellitus in the pregnant ewe: metabolic and cardiovascular effects on the mother and her fetus.

Diabetes mellitus was acutely produced in nine pregnant sheep by the intravenous administration of alloxan 40 mg/kg in the maternal inferior vena cava. Maternal and fetal plasma concentrations of glucose, lactate, beta-hydroxybutyrate, insulin, glucagon, and PaO2, oxygen content, and pH were determined before and at days 1, 3, and 5 after the injection of alloxan. Two animals aborted between days 1 and 3 after alloxan administration. In the other animals, significant changes occurred from baseline to day 5: maternal hyperglycemia (56.8 +/- 5.2 vs. 227.3 +/- 54.6 mg/dl; p less than 0.01), maternal hypoinsulinemia (6.2 +/- 3.5 vs. 1.0 +/- 0.4 microU/ml, p = 0.016); maternal hyperketonemia (beta-hydroxybutyrate: 0.79 +/- 0.27 vs. 4.69 +/- 2.64 mmol/L, p less than 0.01); fetal hyperglycemia (17.0 +/- 2.6 vs. 86.0 +/- 16.2 mg/dl, p less than 0.001); fetal hyperinsulinemia (8.4 +/- 4.5 vs. 19.2 +/- 6.4 microU/ml, p less than 0.001); fetal hyperketonemia (beta-hydroxybutyrate: 0.03 +/- 0.03 vs. 0.06 +/- 0.02 mmol/L, p less than 0.05); fetal hypoxemia (arterial PO2: 21.6 +/- 1.8 vs. 18.0 +/- 2.8 mm Hg, p less than 0.05, and oxygen content: 7.1 +/- 0.5 vs. 4.5 +/- 1.9 vol/dl, p less than 0.02). Thus alloxan administered in the pregnant ewe can produce major metabolic and endocrine derangements acutely simulating those occurring in human insulin-dependent diabetic pregnancy.

Effect of streptozotocin-induced diabetes in primiparous swine on subsequent reproductive performance.

A follow-up study was conducted to determine the effects of streptozotocin-diabetes during the first parity on subsequent reproductive performance of sows. Only in the first parity, two doses of streptozotocin (50 and 100 mg/kg body weight) were administered to two groups of pregnant gilts at 80 d of gestation; a third group of gilts served as a control. Second-parity reproductive performance showed that gestation length, placental weight, mean birth weight of the litter, litter size and number of pigs born alive were not affected (P greater than .05) by maternal diabetes. Maternal serum glucose and fructose were greater (P less than .01) in high-dose sows than in the low-dose and the control dams. Serum free fatty acids (FFA) were higher (P less than .05) in high-dose dams than in control dams at d-1 and d 112 of gestation; no differences were observed between the high-dose and the low-dose during the same period. Liver and kidney weight, as well as DNA and RNA content, were greater (P less than .01) in pigs from high-dose dams than in those of the other treatments. Liver protein was elevated (P less than .01) in the progeny of high-dose dams. Dry matter and percent lipid were higher (P less than .05 and P less than .01, respectively), in pigs from high-dose sows than those from other treatment. Serum glucose, fructose and FFA of piglets were not affected by previous treatment of the dam.(ABSTRACT TRUNCATED AT 250 WORDS)

Gestational diabetes mellitus and impaired glucose tolerance in an aged Macaca mulatta.

Gestational diabetes mellitus was diagnosed in an aged (21-year-old) pregnant rhesus monkey (Macaca mulatta); she was hyperglycemic and had minimal glucose clearance in an intravenous glucose tolerance test (iv-GTT). An overweight (840 g) dead full-term fetus was delivered by cesarean section. A second iv-GTT conducted 3 months later revealed impaired glucose tolerance. While pregnant, the monkey was hyperinsulinemic and showed minimal secretory response to the glucose load. When tested postpartum, the fasting insulin was only slightly elevated, but the insulin response to glucose was still lacking.

The effect of maternal diabetes and fasting on fetal adipose tissue histochemistry in the pig.

The effects of maternal diabetes (induced d 78 of gestation) and food deprivation (last 20 d of gestation) on the histochemical disposition of fetal adipose tissue at 112 d of gestation were determined. In both cases, there was an increased number of fat cell clusters by comparison with the control. In the fetuses of diabetic pigs, there were striking effects on adipocyte size and the extent of lipid filling of presumptive adipose space. In these fetuses, the adipocytes were large and many were unilocular, whereas, those in the fetuses of control and fasted pigs were smaller. The adipose tissue space of the control was "empty" compared with that of fetuses of diabetic pigs. Adipocytes from fetuses of diabetic pigs contained intracellular glycogen deposits, which were not present in adipocytes of control and fasted progeny. Maternal fasting and diabetes increased the number of lipid-containing adipocytes in fetal adipose tissue. An additional effect of maternal diabetes was to increase fetal adipocyte size over that of fetuses of control and fasted pigs.