Low placental angiotensin-converting enzyme expression is related to fetal small for gestational age but not to metabolic control in type 1 diabetic pregnancies

The maternal renin-angiotensin system is involved in blood pressure control and plays a crucial role in fetoplacental nutrition. Pre-gestational type 1 diabetes (PGDM) leads to serious pregnancy complications. We thus performed a longitudinal study to analyse the association of maternal angiotensin-converting enzyme (ACE) serum levels and placental mRNA expression with fetal newborns gestational weight in type 1 diabetes mellitus (T1DM) women. We recruited 65 singleton pregnant women with T1DM. Placental mRNA ACE gene expression was examined using quantitative real-time PCR. Serum ACE levels were measured in the first, second and third trimesters of pregnancy by ELISA commercial kits. Placental expression of ACE mRNA was significantly lower in small for gestational age (SGA) than appropriate for gestational age (AGA) and large for gestational age (LGA) mothers (0.55±0.06 vs 0.78±0.06 and 0.85±0.07 respectively, p=0.003). In the SGA group, the mRNA expression of ACE positively correlated with maternal body mass index (BMI) in the third trimester (r=0.49; p=0.04). In all study groups maternal ACE level was significantly higher in the third trimester (mean 139.91±SD 69.64) compared to the first and second trimesters of pregnancy (13.57±4.32 and 15.69±15.92 respectively). Our data suggest that lower placental ACE gene mRNA expression may have a vital role in the etiology of SGA babies.

Placental vascular endothelial growth factor expression in pregnancies complicated by type 1 diabetes

Type 1 diabetes mellitus (T1DM) is still associated with increased risk of severe maternal and foetal complications but their pathomechanism remains unclear.

OBJECTIVES

we investigated the possible role of placental vascular endothelial growth factor (VEGF) and VEGF single nucleotide polymorphisms (SNP) in foetal development in T1DM pregnancies. Sixty seven pregnant women with T1DM and singleton pregnancy were enrolled into the study. Results demonstrated higher expression of placental VEGF in women who delivered neonates with birth weight (NBW)>4000g. No such correlation was found in the overall T1DM group and in women who delivered appropriate for gestational age (AGA) and small for gestational age (SGA) newborns. We also demonstrated a significant correlation between 3(rd) trimester mean blood glucose, HbA1C and placental VEGF. No such correlation was found for the 1(st) and 2(nd) trimesters. Top placental VEGF expression and placental mass were found in women who delivered large for gestational age (LGA) newborns. We also found a statistically significant difference in homozygous and heterozygous frequency variants of VEGF SNPs in study groups. We conclude that the increased placental VEGF together with impaired metabolic control may have a role in stimulating foetal overgrowth in T1DM pregnancy.

Placental leptin and its receptor genes expression in pregnancies complicated by type 1 diabetes

Type 1 diabetes mellitus (T1DM) is still associated with increased risk for severe maternal and fetal complications but their pathomechanism remains unclear. We investigated into possible role of placental leptin (LEP) and its receptor gene (LEPR) in T1DM pregnancies. Fourty nine pregnant women with T1DM and singleton pregnancy were enrolled into the study. Control group consisted of 15 healthy pregnant women in uncomplicated, singleton gestation. We observed higher expression of LEP and LEPR in T1DM placentas in comparison to healthy subjects. We also noticed greater expression of LEP and LEPR in T1DM pregnancies with large for gestational age (LGA) and appropriate for gestational age (AGA) fetuses in comparison to small for gestational age (SGA) diabetic fetuses and controls. We found a significant positive correlation between placental LEP and LEPR expression and neonatal birthweight in overweight T1DM subjects. No such a correlation was found in T1DM subjects with normal weight and controls. We conclude that increased placental LEP and LEPR expression may have a role in stimulating fetal overgrowth in T1DM pregnancy.

Cardiac disease due to random mitochondrial DNA mutations is prevented by cyclosporin A

Mice expressing an error-prone mitochondrial DNA polymerase rapidly accumulate random mutations in mitochondrial DNA. Expression of the transgene in the heart leads to dilated cardiomyopathy accompanied by a wave of apoptosis in cardiomyocytes, and a vigorous and persistent protective response, including upregulation of the anti-apoptotic protein, Bcl-2. To investigate the role of the mitochondrial permeability transition pore in the development of disease, we treated mice with cyclosporin A (CsA), an inhibitor of pore opening. Drug treatment prevented cardiac dilatation, transgene-specific apoptosis, and upregulation of Bcl-2. It also rescued hearts from the profound decrease in connexin 43, which characterizes the dilatated heart. Treatment with FK506, which like CsA inhibits cytoplasmic calcineurin but not the mitochondrial pore, did not affect disease development, suggesting that the relevant target of CsA was the mitochondrial pore. These data implicate breakdowns in the mitochondrial permeability barrier in pathogenesis of elevated frequencies of mtDNA mutations.

EFFECT OF NALTREXONE ADMINISTRATION ON SHORT-TERM MEMORY IN CHRONICALLY ETHANOL-TREATED OUTBRED RATS

AIMS

The purpose of this study was to evaluate the effect of naltrexone treatment for 21 consecutive days on short-term memory in ethanol-preferring and non-preferring outbred rats.

METHODS

Ethanol preferring, non-preferring and control Wistar rats were treated with naltrexone [0.1 mg/kg intraperitoneally (i.p.)] for 21 consecutive days. Short-term memory was assessed by using an olfactory social recognition test.

RESULTS

A single administration of naltrexone (0.1 mg/kg i.p.) to non-ethanol-treated animals facilitated social memory, whereas the drug did not affect short-term memory in either group of chronically ethanol-treated rats. Multiple naltrexone treatment also lowered alcohol intake in ethanol-preferring rats.

CONCLUSION

Naltrexone-ethanol interaction does not seem to produce any negative effect on the short-term memory in outbred rats.

Lack of ifenprodil anxiolytic activity after its multiple treatment in chronically ethanol-treated rats

AIMS

The purpose of this study was to assess the anxiolytic activity of ifenprodil in Warsaw high-preferring (WHP) and low-preferring (WLP) rats after chronic ethanol treatment.

METHODS

WHP and WLP animals, their paired-ethanol-naive groups and control Wistar rats were treated with ifenprodil (1.0 mg/kg, intraperitoneally) for 21 consecutive days. Anxiolytic activity was evaluated by using the two-compartment exploratory test. In addition, the locomotor activity paradigm was also assessed.

RESULTS

Ifenprodil did not affect this paradigm in all investigated groups. The ethanol treatment led to lowering of anxiolytic scores in WHP rats. Multiple ifenprodil administration showed an anxiogenic-like activity in both WHP- and WLP-ethanol-treated groups.

CONCLUSIONS

Our results suggest that, under some conditions, the role of ifenprodil in the treatment of alcoholism may be insufficient to support its use.

Ethanol facilitation of short-term memory in adult rats with a disturbed circadian cycle

The aim of this study was to evaluate the effect of 3-month ethanol treatment on olfactory social memory test performance using two inter-exposure intervals [30 min: short-term recognition (STR); or 120 min: long-term recognition (LTR)] in adult rats with a disturbed circadian cycle (DCC). Ethanol treatment both in ethanol-preferring and -non-preferring groups improved the STR task compared to control rats. However, LTR procedure triggered the opposite tendency. Moreover, no differences between control rats with DCC and those with normal diurnal rhythm in STR and LTR paradigms were observed. Our results suggest that, under some conditions, alcohol facilitates short-term memory in adult rats.

The effects of midazolam and morphine on analgesic and sedative activity of ketamine in rats

The aim of this study was to investigate possible interactions between the analgesic activity of ketamine (an N-methyl-D-aspartate antagonist), midazolam (a benzodiazepine derivative) and morphine using the tail-flick test in rats. Animals were treated s.c. with ketamine (1.0-10.0 mg/kg), midazolam (0.3 mg/kg), or morphine (0.6 mg/kg) alone. or in combination The strongest analgesic effect of ketamine was observed after 3.0 mg/kg. In higher doses no enhancement of ketamine activity were found. After morphine and ketamine (3.0 mg/kg) or morphine, midazolam and ketamine co-administration. higher antinociceptive effects compared to ketamine activity were found. Rats administered midazolam and ketamine (3.0 mg/kg) showed a decrease of the effect of ketamine analgesia, and the antinociceptive effect of the three-component mixture was lower than after co-injection of morphine and ketamine. The interaction of these two compounds with ketamine (5.0 mg/kg) occurred in a different manner, because midazolam led to a strong enhancement of ketamine analgesia. After morphine and ketamine (5.0 mg/kg) administration, very weak increase of ketamine analgesia was observed. The results of this study allow better understanding of the alteration of the analgesic effects of low doses of ketamine under the influence of morphine and midazolam.

Analysis of the distribution of peripheral blood lymphocyte subsets associated with chronic ethanol treatment in rats with a disturbed circadian cycle

The present study examined the composition of lymphoid subsets in the peripheral blood of alcohol-preferring (PRF) and non-preferring (NPF) rats, in an experimental model of alcoholism involving the disruption of the circadian cycle. The absolute and relative number of lymphocytes in specific subsets (CD3, CD4, CD8, NK, CD45RA) were measured using the flow cytometry method. When control animals with a disrupted circadian cycle (KN) were compared with a normal diurnal cycle group (KD), it was noticed that this disruption led to an increase in the absolute number of lymphocytes T (CD3(+), CD4(+) and CD8(+) cells) and lymphocytes B (CD45RA(+)). After the period of time when the alcohol preference was seen, there was a change in response - as measured by the numbers and the percentage of lymphoid subsets in NPF rats - involving a lowering of NK and CD45RA(+) cells. It seems that these animals exhibit higher sensitivity towards prolonged ethanol intoxication. However, the PRF animals - for whom the analysed values were close to those of the control group (KN) - tolerated the toxic effects of ethanol better and this may be related to their genetic predisposition.

Zolpidem involvement on memory and hypnotic effect of ethanol in chronically ethanol-treated rats

Multiple (10x) treatment of zolpidem (1.0 or 2.0 mg/kg, orally, p.o.) led to different effects in chronically ethanol-treated and control rats. In control rats, after repeated zolpidem administration, a weaker, when compared to single administration, hypnotic effect of ethanol was observed, which may be the result of tolerance developed towards the inhibitory effect of zolpidem. However, in chronically ethanol-treated rats, the multiple zolpidem treatment led to prolongation of ethanol-induced sleep similar to the values observed in non-zolpidem-treated control animals. This suggests that zolpidem multiple administration may inhibit tolerance towards ethanol in chronically ethanol-treated rats. In the experiment with zolpidem, there were effects on performance in a memory test and the impairment of passive avoidance task after multiple drug treatment when compared to the effects after single administration in control rats. In contrast, in chronically ethanol-treated rats, amplification of latency (especially after 2.0 mg/kg) was observed. The possible relationship between ethanol-induced sedation and latency values would be consistent with a higher contribution of the inhibitory effect of zolpidem, than a direct influence on memory processes in chronically ethanol-treated rats.