LY 393558

Clinical and immunohistochemical performance of lyophilized platelet-rich fibrin (Ly-PRF) on tissue regeneration.[Pubmed:28192870]

Clin Implant Dent Relat Res. 2017 Jun;19(3):466-477.

BACKGROUND: Platelet-rich fibrin (PRF) has been widely used in oral implantology and other fields, but benefits of the fresh PRF (FPRF (fresh platelet-rich fibrin)) were consequently limited because of its short-term application. Thus, a protocol for the combination of PRF and lyophilization comes up in the present study to address the issue of PRF storage and delayed clinical application, which has little been reported in this field at home and abroad by now. PURPOSE: The aim of the present study was to evaluate the applicability of lyophilized platelet-rich fibrin (Ly-PRF) used as the scaffold material for craniofacial tissue regeneration and to compare its biochemical properties with commonly used fresh PRF. MATERIALS AND METHODS: Two volunteers with both genders were selected as the source of PRF and Ly-PRF samples. Macro- and micro-scopic appearance evaluation as well as immunohistochemical comparison were performed on PRF samples before and after freeze-drying at -196 degrees C. The second experimental phase was to observe clinical performance when fresh and lyophilized PRF were applied in guided bone regeneration (GBR) operations in 39 patients losing teeth in the anterior maxillary region who required an oral implantation followed by labial bone grafting. RESULTS: The conventional histological and transmission electron microscopy images showed the microstructure of Ly-PRF, which resembled a mesh containing apparently irregularly shaped platelets with less alpha-granule than fresh PRF in micro and a translucent membrane with less elasticity than fresh PRF in macro. Simultaneous immunohistological staining results showed positive expression of PDGF-BB, IL-1, IL-4, TNF, TGF-beta1 in both fresh and lyophilized PRF, while the expression of PDGF-BB, IL-1, TNF, TGF-beta1 has no statistical difference between them (P > .05) but that of IL-4 in Ly-PRF is statistically higher than in fresh PRF (P < .05). When applied in GBR operations, there were no significant differences between Ly-PRF and FPRF in factors of histological and clinical evaluations (i.e., color, swelling, bleeding of the mucosa, pain leveland, and remodeling of hard tissue) performed 3 days, 7 days, and 4 months after the surgery (P > .05). CONCLUSIONS: This study strongly supports that lyophilization at -196 degrees C does not largely influence the expression of bioactive factors, the microstructure of fibrinogen or the clinical effects of PRF.

Expansion of CD11b(+)Ly-6C(+) myeloid-derived suppressor cells (MDSCs) driven by galectin-9 attenuates CVB3-induced myocarditis.[Pubmed:28110209]

Mol Immunol. 2017 Mar;83:62-71.

Galectin-9 is known to play a role in the modulation of innate and adaptive immunity to ameliorate CVB3-induced myocarditis. In the present study, we found that galectin-9 induced the expansion of CD11b(+)Ly-6C(+) myeloid-derived suppressor cells (MDSCs) in the heart from CVB3-infected mice. Adoptive transfer of CD11b(+)Ly-6C(+) MDSCs significantly alleviated myocarditis accompanied by increased Th2 and Treg frequency and anti-inflammatory cytokines expression in the heart tissue. Moreover, Ly6C(+) MDSCs, but not Ly6G(+) cells, expressed Arg-1 and NOS2, and suppressed CD4(+) T cell proliferation in vitro in an Arg-1-dependent mechanism; an event that was reversed with treatment of either an Arg-1 inhibitor or addition of excess l-arginine. Furthermore, Ly6C(+) MDSCs co-expressed higher levels of F4/80, Tim-3, and IL-4Ralpha, and had the plasticity to up-regulate NOS2 or Arg-1 in response to IFN-gamma or IL-4 treatment. The present results indicate that galectin-9 expands CD11b(+)Ly-6C(+) MDSCs to ameliorate CVB3-induced myocarditis.

Assessment of roles for the Rho-specific guanine nucleotide dissociation inhibitor Ly-GDI in platelet function: a spatial systems approach.[Pubmed:28148498]

Am J Physiol Cell Physiol. 2017 Apr 1;312(4):C527-C536.

On activation at sites of vascular injury, platelets undergo morphological alterations essential to hemostasis via cytoskeletal reorganizations driven by the Rho GTPases Rac1, Cdc42, and RhoA. Here we investigate roles for Rho-specific guanine nucleotide dissociation inhibitor proteins (RhoGDIs) in platelet function. We find that platelets express two RhoGDI family members, RhoGDI and Ly-GDI. Whereas RhoGDI localizes throughout platelets in a granule-like manner, Ly-GDI shows an asymmetric, polarized localization that largely overlaps with Rac1 and Cdc42 as well as microtubules and protein kinase C (PKC) in platelets adherent to fibrinogen. Antibody interference and platelet spreading experiments suggest a specific role for Ly-GDI in platelet function. Intracellular signaling studies based on interactome and pathways analyses also support a regulatory role for Ly-GDI, which is phosphorylated at PKC substrate motifs in a PKC-dependent manner in response to the platelet collagen receptor glycoprotein (GP) VI-specific agonist collagen-related peptide. Additionally, PKC inhibition diffuses the polarized organization of Ly-GDI in spread platelets relative to its colocalization with Rac1 and Cdc42. Together, our results suggest a role for Ly-GDI in the localized regulation of Rho GTPases in platelets and hypothesize a link between the PKC and Rho GTPase signaling systems in platelet function.

Short-term dabigatran interruption before cardiac rhythm device implantation: multi-centre experience from the RE-LY trial.[Pubmed:28339794]

Europace. 2017 Oct 1;19(10):1630-1636.

Aims: Cardiac implantable electronic device (CIED) surgery is commonly performed in patients with atrial fibrillation (AF). The current analysis was undertaken to compare peri-operative anticoagulation management, bleeding, and thrombotic events in AF patients treated with dabigatran vs. warfarin. Methods and results: This study included 611 patients treated with dabigatran vs. warfarin who underwent CIED surgery during the RE-LY trial. Among 201 warfarin-treated patients, warfarin was interrupted a median of 144 (inter-quartile range, IQR: 120-216) h, and 37 (18.4%) patients underwent heparin bridging. In dabigatran-treated patients (216 on 110 mg bid and 194 on 150 mg bid), the duration of dabigatran interruption was a median of 96 (IQR: 61-158) h. Pocket hematomas occurred in 9 (2.20%) patients on dabigatran and 8 (3.98%) patients on warfarin (P = 0.218). The occurrence of pocket hematomas was lower with dabigatran compared with warfarin with heparin bridging (RD: -8.62%, 95% CI: -24.15 to - 0.51%, P = 0.034) but not when compared with warfarin with no bridging (P = 0.880). Ischemic stroke occurred in 2 (0.3%) patients; one in the warfarin group (without bridging) and one in the dabigatran 150 mg bid group (P = 0.735). Conclusion: In patients treated with dabigatran undergoing CIED surgery, interruption of dabigatran is associated with similar or lower incidence of pocket hematoma, when compared with warfarin interruption without or with heparin bridging, respectively. Whether uninterrupted dabigatran can reduce pocket hematoma or ischemic stroke remains to be evaluated.

Functional interactions between 5-hydroxytryptamine receptors and the serotonin transporter in pulmonary arteries.[Pubmed:15659538]

J Pharmacol Exp Ther. 2005 May;313(2):539-48.

Pulmonary arterial 5-hydroxytryptamine (serotonin) (5-HT) transporter (SERT)-, 5-HT receptor expression, and 5-HT-induced vasoconstriction can be increased in pulmonary hypertension. These variables were studied in normoxic and hypoxic Fawn-Hooded (FH) and Sprague-Dawley (SD) rats. Furthermore, we compared the functional effects of SERT inhibitors and 5-HT receptor antagonists against 5-HT-induced vasoconstriction of pulmonary arteries. SERT and 5-HT(1B) expression was greater in FH rat lungs than in SD rats, as was 5-HT-mediated vasoconstriction. The 5-HT(2A) receptor antagonist ketanserin and the 5-HT(1B) receptor antagonist SB224289 (1'-methyl-5-[[2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]carbonyl ]-2,3,6,7-tetrahydro-spiro-[furo] 2, 3-f]indole-3,4'-piperidine]) inhibited responses to 5-HT in all vessels. The combined 5-HT(1B) receptor/SERT antagonist LY393558 (1-[2-[4-(6-fluoro-1H-indol-3-yl)-3,6-dihydro-1(2H)-pyridinyl]ethyl]-3-isopropyl- 6-(methylsulfonyl)-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide) was the most potent inhibitor of constriction in all vessels. SERT inhibitors citalopram and fluoxetine inhibited responses to 5-HT in SD vessels. However, these inhibitors potentiated responses to 5-HT in FH vessels. After exposure of rats to 2 weeks of hypoxia, there was increased 5-HT-mediated vasoconstriction and a profound decrease in SERT expression in both the FH and SD rat lung. Accordingly, citalopram had no effect on 5-HT-induced constriction in SD rat vessels and markedly less effect in FH rat vessels. Ketanserin, SB224289, and LY393558 inhibited responses to 5-HT in all hypoxic rat vessels. LY393558 was the most potent antagonist, and there was synergy between the effects of fluoxetine and SB224289 when given simultaneously. The results suggest that, in FH rats, SERT inhibitors may increase pulmonary vasoconstriction, but this can be inhibited by simultaneous 5-HT(1B) receptor antagonism. There is synergy between the inhibitory effects of 5-HT(1B) receptor antagonists and SERT inhibitors on 5-HT-induced pulmonary vasoconstriction.

LY393558, a 5-hydroxytryptamine reuptake inhibitor and 5-HT(1B/1D) receptor antagonist: effects on extracellular levels of 5-hydroxytryptamine in the guinea pig and rat.[Pubmed:11734183]

Eur J Pharmacol. 2001 Nov 30;432(1):19-27.

The stimulation of terminal 5-HT(1B/1D) autoreceptors limits the effects of selective serotonin reuptake inhibitors on extracellular levels of 5-hydroxytryptamine (5-HT, serotonin) in vivo. Microdialysis studies show that acute oral administration of LY393558-a 5-HT reuptake inhibitor and antagonist at both the human 5-HT(1B) and 5-HT(1D) receptor-in the dose range 1-20 mg/kg, increases extracellular levels of 5-HT in both the guinea pig hypothalamus and rat frontal cortex. In both species, the levels of 5-HT that were attained were higher than following an acute, maximally effective dose of fluoxetine (20 mg/kg orally), reaching approximately 1500% in the guinea pig hypothalamus and 700% in the rat frontal cortex. In both species, the response to LY393558 (10 mg/kg p.o.) was impulse dependent, being absent in the presence of tetrodotoxin delivered at 1 microM via the microdialysis probe. The sensitivity to tetrodotoxin contrasted with the effects seen with DL-fenfluramine. Studies in rats showed that the microdialysate 5-HT concentration achieved in the frontal cortex after an acute challenge with LY393558 (5 mg/kg p.o.) was significantly greater than following a chronic regime of fluoxetine treatment (10 mg/kg/day orally for 21 days). Moreover, in rats chronically treated with LY393558 (5 mg/kg/day orally for 21 days), the mean basal concentration, 24 h after the final pretreatment dose, was of the same magnitude as that following chronic fluoxetine. However, in contrast to the response seen in fluoxetine-pretreated animals, a challenge dose of LY393558 still elicited a further increase in extracellular 5-HT in LY393558-pretreated animals. LY393558 is a potent 5-HT reuptake inhibitor and 5-HT(1B/1D) receptor antagonist. Microdialysis studies show that acute oral administration increases extracellular levels of 5-HT, by an impulse-dependent mechanism, above those produced by a maximally effective dose of fluoxetine, and in rats to levels only achieved following chronic fluoxetine treatment. Its neurochemical profile in vivo suggests that it may be a more effective antidepressant with the potential for producing an earlier onset of clinical activity than selective serotonin reuptake inhibitors.

In vitro activity of LY393558, an inhibitor of the 5-hydroxytryptamine transporter with 5-HT(1B/1D/2) receptor antagonist properties.[Pubmed:11734182]

Eur J Pharmacol. 2001 Nov 30;432(1):9-17.

1-[2-[4-(6-fluoro-1H-indol-3-yl)-3,6-dihydro-1(2H)-pyridinyl]ethyl]-3-isopropyl-6 -(methylsulphonyl)-3,4-dihydro-1H-2,1,3-benzothiadiazine-2,2-dioxide (LY393558) is a potent inhibitor of [3H]5-hydroxytryptamine ([3H]5-HT) uptake into rat cortical synaptosomes (pIC(50)=8.48+/-0.12). It produces a dextral shift of the 5-HT dose-response curves for the binding of GTPgamma[35S] to human 5-HT(1B) (pK(b)=9.05+/-0.14) and 5-HT(1D) (pK(b)=8.98+/-0.07) receptors and inhibits the contractile response of the rabbit saphenous vein to the 5-HT(1B/D) receptor agonist, sumatriptan (pK(b)=8.4+/-0.2). In addition, it is an antagonist at the 5-HT(2A) (pK(i)=7.29+/-0.19) and 5-HT(2B) (pK(i)=7.35+/-0.11) receptors. Presynaptic autoreceptor antagonist activity was demonstrated by its ability to potentiate the K(+)-induced outflow of [3H]5-HT from guinea pig cortical slices (pEC(50)=7.74+/-0.05 nM) in which the 5-HT transporter had been inhibited by a maximally effective concentration of paroxetine. It is concluded that LY393558 should be an effective antidepressant with the potential to produce an earlier onset of efficacy than selective serotonin uptake inhibitors.