Abstract-Vascular endothelial growth factor (VEGF) is known to induce the release of nitric oxide (NO) from endothelial cells. However, the effect of NO on VEGF synthesis is not clear. Accordingly, the effect of endogenous and exogenous NO on VEGF synthesis by rat vascular smooth muscle cells (VSMCs) was investigated. Two in vitro models were used:(1) VSMCs stimulated to produce NO by treatment with interleukin (IL)-1␤ (10 ng/mL) and (2) VSMCs lipotransfected with pKecNOS plasmid, containing the endothelial constitutive NO synthase (ecNOS) cDNA. The synthesis of NO was inhibited by N -nitro-L-arginine methyl ester (L-NAME, 2 to 5 mmol/L) or diaminohydroxypyrimidine (DAHP, 2.5 to 5 mmol/L), inhibitors of NOS and GTP cyclohydrolase I, respectively. Some cells treated with L-NAME or DAHP were supplemented with L-arginine (10 mmol/L) or tetrahydrobiopterin (BH 4 ; 100 mol/L), respectively. In addition, we studied the effect of sodium nitroprusside (SNP; 10 and 100 mol/L) and chemically related compounds, potassium ferrocyanide and ferricyanide, on VEGF generation. IL-1␤ induced iNOS expression and NO generation and significantly upregulated VEGF mRNA expression and protein synthesis. L-NAME and DAHP totally inhibited NO generation and decreased the IL-1␤-upregulated VEGF synthesis by 30% to 40%. Supplementation with L-arginine or BH 4 increased NO generation by L-NAME-or DAHP-treated cells, and VEGF synthesis was augmented by addition of BH 4 . The cells generating NO after pKecNOS transfection released significantly higher amounts of VEGF than cells transfected with control plasmids. Inhibition of NO generation by L-NAME decreased VEGF synthesis. In contrast to the effect of endogenous NO, we observed the inhibition of VEGF synthesis in the presence of high (10 or 100 mol/L) concentrations of SNP. This effect was mimicked by chemically related ferricyanide and ferrocyanide compounds, suggesting that the inhibitory effect of sodium nitroprusside may be mediated by an NO-independent mechanism. The results indicate that endogenous NO enhances VEGF synthesis. The positive interaction between endogenous NO and VEGF may have implications for endothelial regeneration after balloon angioplasty and for angiogenesis.

The extracellular concentration of the two main neurotransmitters glutamate and GABA is low but not negligible which enables a number of tonic actions. The effects of ambient GABA vary in a region-, cell-type, and age-dependent manner and can serve as indicators of disease-related alterations. Here we explored the tonic inhibitory actions of GABA in Huntington's disease (HD). HD is a devastating neurodegenerative disorder caused by a mutation in the huntingtin gene. Whole cell patch clamp recordings from striatal output neurons (SONs) in slices from adult wild type mice and two mouse models of HD (Z_Q175_KI homozygotes or R6/2 heterozygotes) revealed an HD-related reduction of the GABA(A) receptor-mediated tonic chloride current (ITonic(GABA)) along with signs of reduced GABA(B) receptor-mediated presynaptic depression of synaptic GABA release. About half of ITonic(GABA) depended on tetrodotoxin-sensitive synaptic GABA release, but the remaining current was still lower in HD. Both in WT and HD, ITonic(GABA) was more prominent during the first 4 h after preparing the slices, when astrocytes but not neurons exhibited a transient depolarization. All further tests were performed within 1–4 h in vitro. Experiments with SNAP5114, a blocker of the astrocytic GABA transporter GAT-3, suggest that in WT but not HD GAT-3 operated in the releasing mode. Application of a transportable substrate for glutamate transporters (D-aspartate 0.1–1 mM) restored the non-synaptic GABA release in slices from HD mice. ITonic(GABA) was also rescued by applying the hyperagonist gaboxadol (0.33 μM). The results lead to the hypothesis that lesion-induced astrocyte depolarization facilitates non-synaptic release of GABA through GAT-3. However, the capacity of depolarized astrocytes to provide GABA for tonic inhibition is strongly reduced in HD.

Recently, the diagnostic criteria of preeclampsia have been changed. No studies are available in the literature that analyzed in detail the differences between early-onset preeclampsia (EOP) and late-onset preeclampsia (LOP), taking into account the International Society for the Study of Hypertension in Pregnancy (ISSHP) criteria. Thus, we sought to retrospectively investigate in detail the differences in clinical and laboratory outcomes between EOP and LOP diagnosed according to the ISSHP criteria. A retrospective cohort study was conducted in 214 women with singleton pregnancies and preeclampsia admitted to the Department of Obstetrics and Perinatology of the University Hospital in Kraków, Poland, from 2013 to 2017 (113 (52.8%) women with EOP and 101 (47.2%) women with LOP). Electronic medical records were reviewed for demographics and medical history, laboratory tests, and delivery and neonatal data. Patients with preeclampsia accounted for 1.7% of the women who delivered during the study period. The EOP and LOP groups did not differ in the distribution of risk factors for preeclampsia. The most common risk factor was primiparity, which was observed in 72.0% of cases. Regarding the ISSHP diagnostic criteria, the two groups differed in the incidence of fetal growth restriction (p=0.0009), hemolysis (p=0.0416), and neurological complications (p=00342), which were found more often in the EOP group. In addition, the EOP group had more frequent occurrence of severe cardiorespiratory (p<0.0001) and hematological (p=0.0127) complications, adverse fetoplacental conditions (p<0.0001), and severe fetoplacental complications (p=0.0003). Children born to women with EOP had lower Apgar scores (p<0.001) and higher rates of intraventricular hemorrhage (p<0.0001), respiratory disorders requiring mechanical ventilation (p<0.0001), and early (p=0.0004) and late sepsis (p=0.002). EOP differed from LOP in terms of maternal and perinatal adverse outcomes. The observed higher rates of fetoplacental adverse conditions and severe complications indicate a significant contribution of impaired placentation to the etiopathogenesis of EOP.

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