Peri-Interventional Triple Therapy with Dabigatran Modifies Vasomotion after Bare-Metal Stent Implantation in a Pig Coronary Artery Model.

(1) Background: Coronary artery stenting leads to local inflammation, disturbs vasomotion, and slows endothelialization, increasing vascular thrombus risk. We used a pig stenting coronary artery model to assess how peri-interventional triple therapy with dabigatran ameliorates these effects. (2) Methods: In a total of 28 pigs bare-metal stents were implanted. Four days before the percutaneous coronary intervention (PCI), we started 16 of the animals on dabigatran, maintained through 4 days after the procedure. As controls, the remaining 12 pigs received no therapy. In both groups, dual antiplatelet therapy (DAPT) (clopidogrel, 75 mg plus aspirin, 100 mg) was administered until animals were euthanized. Just after the PCI and on day 3 after the procedure, we performed optical coherence tomography (OCT) in eight animals in the dabigatran group and four controls and euthanized them. We followed the eight remaining animals in each group with OCT and angiography for one month before euthanizing them and performed in vitro myometry and histology on harvested coronary arteries from all animals. (3) Results: The dabigatran group showed a significantly increased vasoconstriction at 3 days after PCI (10.97 ± 3.85 mN vs. 7.32 ± 5.41 mN, p = 0.03), but we found no differences between endothelium-dependent and -independent vasodilatation. We also found no group differences in OCT, quantitative angiography, or histomorphometry findings. (4) Conclusions: Starting a short course of dabigatran just before PCI and continuing for a 3-day window along with usual post-PCI DAPT is associated with enhanced vasoconstriction after bare-metal stent implantation without reducing neointimal formation at one month.

Peri-interventional Triple Therapy With Dabigatran Improves Vasomotion and Promotes Endothelialization in Porcine Coronary Stenting Model.

Objective: We evaluated the short and long-term effect of peri-interventional dabigatran therapy on vasomotion, endothelialization, and neointimal formation in a porcine coronary artery stenting model. Background: Stenting of coronary arteries induces local inflammation, impairs vasomotion and delays endothelialization. Methods: Twenty-eight animals underwent percutaneous coronary intervention (PCI) with drug eluting stents. Sixteen pigs started dabigatran therapy 4 days prior to PCI and continued for 4 days post-stenting, while 12 animals served as controls. Post-stenting dual antiplatelet therapy (75 mg clopidogrel and 100 mg aspirin) was continued in both groups until termination. Immediately post-stenting and at day 3 optical coherence tomography (OCT) was performed in all animals, followed by euthanasia of 8 dabigatran and 4 control animals. The remaining pigs (8 of each group) were followed up for 1 month, with control angiography and OCT. Tissue burden (degree of peri-strut structure-thrombus and/or fibrin) was evaluated. After euthanasia coronary arteries were harvested for in-vitro myometry and histology. Results: Thrombin generation was lower (p < 0.001) and tissue burden (0.83 ± 0.98 vs. 3.0 ± 2.45; p = 0.031) was significantly decreased in dabigatran treated animals. After 3 days post-PCI endothelium-dependent vasodilation was significantly improved (77 ± 40% vs. 41 ± 31%, p = 0.02) in dabigatran animals. Neither quantitative angiography nor histomorphometry showed differences between the groups. Endothelialization was faster in the dabigatran group as compared with controls (p = 0.045). Conclusion: Short-term peri-interventional triple therapy with dabigatran, aspirin, and clopidogrel led to an enhanced endothelium dependent vasodilation and faster endothelialization. However, neointimal formation 1-month after stent implantation was comparable between groups.

The Effects of Female Sexual Hormones on the Expression of Aquaporin 5 in the Late-Pregnant Rat Uterus.

Thirteen mammalian aquaporin (AQP) water channels are known, and few of them play a role in the mammalian reproductive system. In our earlier study, the predominance of AQP5 in the late-pregnant rat uterus was proven. Our current aim was to investigate the effect of estrogen- and gestagen-related compounds on the expression of the AQP5 channel in the late-pregnant rat uterus. Furthermore, we examined the effect of hormonally-induced preterm delivery on the expression of AQP5 in the uterus. We treated pregnant Sprague-Dawley rats subcutaneously with 17ß-estradiol, clomiphene citrate, tamoxifen citrate, progesterone, levonorgestrel, and medroxyprogesterone acetate. Preterm delivery was induced by subcutaneous mifepristone and intravaginal prostaglandin E2. Reverse-transcriptase PCR and Western blot techniques were used for the detection of the changes in AQP5 mRNA and protein expressions. The amount of AQP5 significantly increased after progesterone and progesterone analogs treatment on 18 and 22 days of pregnancy. The 17ß-estradiol and estrogen receptor agonists did not influence the AQP5 mRNA level; however, estradiol induced a significant increase in the AQP5 protein level on the investigated days of gestation. Tamoxifen increased the AQP5 protein expression on day 18, while clomiphene citrate was ineffective. The hormonally-induced preterm birth significantly decreased the AQP5 level similarly to the day of delivery. We proved that AQP5 expression is influenced by both estrogen and progesterone in the late-pregnant rat uterus. The influence of progesterone on AQP5 expression is more predominant as compared with estrogen.

Electroporation-delivered transdermal neostigmine in rats: equivalent action to intravenous administration.

PURPOSE: Transdermal electroporation has become one of the most promising noninvasive methods for drug administration, with greatly increased transport of macromolecules through the skin. The cecal-contracting effects of repeated transdermal electroporation delivery and intravenous administration of neostigmine were compared in anesthetized rats. METHODS: The cecal contractions were detected with implantable strain gauge sensors, and the plasma levels of neostigmine were followed by high-performance liquid chromatography. RESULTS: Both intravenously and EP-administered neostigmine (0.2-66.7 µg/kg) increased the cecal contractions in a dose-dependent manner. For both the low doses and the highest dose, the neostigmine plasma concentrations were the same after the two modes of administration, while an insignificantly higher level was observed at a dose of 20 µg/kg after intravenous administration as compared with the electroporation route. The contractile responses did not differ significantly after the two administration routes. CONCLUSION: The results suggest that electroporation-delivered neostigmine elicits action equivalent to that observed after intravenous administration as concerning both time and intensity. Electroporation permits the delivery of even lower doses of water-soluble compounds through the skin, which is very promising for clinical practice.

The effects of progesterone on the alpha2-adrenergic receptor subtypes in late-pregnant uterine contractions in vitro.

BACKGROUND: The adrenergic system and progesterone play major roles in the control of the uterine function. Our aims were to clarify the changes in function and expression of the α2-adrenergic receptor (AR) subtypes after progesterone pretreatment in late pregnancy. METHODS: Sprague Dawley rats from pregnancy day 15 were treated with progesterone for 7 days. The myometrial expressions of the α2-AR subtypes were determined by RT-PCR and Western blot analysis. In vitro contractions were stimulated with (-)-noradrenaline, and its effect was modified with the selective antagonists BRL 44408 (α2A), ARC 239 (α2B/C) and spiroxatrine (α2A). The accumulation of myometrial cAMP was also measured. The activated G-protein level was investigated via GTPγS binding assays. RESULTS: Progesterone pretreatment decreased the contractile effect of (-)-noradrenaline through the α2-ARs. The most significant reduction was found through the α2B-ARs. The mRNA of all of the α2-AR subtypes was increased. Progesterone pretreatment increased the myometrial cAMP level in the presence of BRL 44408 (p < 0.001), spiroxatrine (p < 0.001) or the spiroxatrine + BRL 44408 combination (p < 0.05). Progesterone pretreatment increased the G-protein-activating effect of (-)-noradrenaline in the presence of the spiroxatrine + BRL 44408 combination. CONCLUSIONS: The expression of the α2-AR subtypes is progesterone-sensitive. It decreases the contractile response of (-)-noradrenaline through the α2B-AR subtype, blocks the function of α2A-AR subtype and alters the G protein coupling of these receptors, promoting a Gs-dependent pathway. A combination of α2C-AR agonists and α2B-AR antagonists with progesterone could be considered for the treatment or prevention of preterm birth.

The effects of estrogen on the α2-adrenergic receptor subtypes in rat uterine function in late pregnancy in vitro.

AIM: To assess the effect of 17ß-estradiol pretreatment on the function and expression of α2- adrenergic receptors (ARs) subtypes in late pregnancy in rats. METHODS: Sprague-Dawley rats (n=37) were treated with 17ß-estradiol for 4 days starting from the 18th day of pregnancy. The myometrial expression of the α2-AR subtypes was determined by real time polymerase chain reaction and Western blot analysis. In vitro contractions were stimulated with (-)-noradrenaline, and its effect was modified with the selective antagonists BRL 44408 (α2A), ARC 239 (α2B/C), and spiroxatrine (α2A). The cyclic adenosine monophosphate (cAMP) accumulation was also measured. The activated G-protein level was investigated by guanosine 5'-O-[gamma-thio]triphosphate (GTPγS) binding assay. RESULTS: 17ß-estradiol pretreatment decreased the contractile effect of (-)-noradrenaline via the α2-ARs, and abolished the contractile effect via the α2B-ARs. All the α2-AR subtypes' mRNA was significantly decreased. 17ß-estradiol pretreatment significantly increased the myometrial cAMP level in the presence of BRL 44408 (P=0.001), ARC 239 (P=0.007), and spiroxatrine (P=0.045), but did not modify it in the presence of spiroxatrine + BRL 44408 combination (P=0.073). It also inhibited the G-protein-activating effect of (-)-noradrenaline by 25% in the presence of BRL 44408 + spiroxatrine combination. CONCLUSIONS: The expression of the α2-AR subtypes is sensitive to 17ß-estradiol, which decreases the contractile response of (-)-noradrenaline via the α2B-AR subtype, and might cause changes in G-protein signaling pathway. Estrogen dysregulation may be responsible for preterm labor or uterine inertia via the α2-ARs.

The effects of female sexual hormones on the expression and function of α1A- and α1D-adrenoceptor subtypes in the late-pregnant rat myometrium.

The aim of the study was to investigate the roles of α1-adrenoceptor subtypes in the last-day pregnant rat uterus in vitro by the administration of subtype-specific antagonists (the α1A-adrenoceptor antagonist WB 4101 and the α1D-adrenoceptor antagonist BMY 7378) after 17ß-estradiol or progesterone pretreatment. In isolated organ bath studies, contractions were elicited with (-)-noradrenaline (10(-8)-10(-5)M) in the presence of propranolol (10(-5)M) and yohimbine (10(-6)M) in order to avoid ß-, and α2-adrenergic action. The myometrial expressions of the α1-adrenoceptor subtypes were determined by means of the real time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting techniques. The activated G protein levels were investigated through radiolabelled GTP binding assays. Both 17ß-estradiol and progesterone pretreatment changed the myometrial contracting effect of (-)-noradrenaline. In the presence of WB 4101, progesterone pretreatment decreased the (-)-noradrenaline-induced myometrial contraction. In the presence of BMY 7378, both the 17ß-estradiol and the progesterone pretreatment reduced the effect of (-)-noradrenaline. The mRNA and protein expressions of the α1A-adrenoceptors were decreased after 17ß-estradiol pretreatment. (-)-Noradrenaline increased the [(35)S]GTPγS binding of the α1-adrenoceptors, which was most markedly elevated by progesterone. Pertussis toxin inhibited the [(35)S]GTPγS binding-stimulating effect of (-)-noradrenaline, indicating the role of Gi proteins in the signal mechanisms. 17ß-estradiol pretreatment blocks the expression of the α1A-adrenoceptors, whereas it does not influence the expression of the α1D-adrenoceptors. Progesterone pretreatment does not have any effect on the myometrial mRNA and protein expressions of the α1-adrenoceptors, but it alters the G protein coupling of these receptors, promoting a Gi-dependent pathway.