pH-dependent distribution of chlorin e6 derivatives across phospholipid bilayers probed by NMR spectroscopy

The pH-dependent membrane adsorption and distribution of three chlorin derivatives, chlorin e6 (CE), rhodin G7 (RG), and monoaspartyl-chlorin e6 (MACE), in the physiological pH range (pH 6-8) were probed by NMR spectroscopy. Unilamellar vesicles consisting of dioleoyl-phosphatidyl-choline (DOPC) were used as membrane models. The chlorin derivatives were characterized with respect to their aggregation behavior, the pK(a) values of individual carboxylate groups, the extent of membrane adsorption, and their flip-flop rates across the bilayer membrane for pH 6-8. External membrane adsorption was found to be lower for RG than for CE and MACE. Both electrostatic interactions and the extent of aggregation seemed to be the main determinants of membrane adsorption. Rate constants for chlorin transfer across the membrane were found to correlate strongly with the pH of the surrounding medium, in particular, for CE and RG. In acidic solution, CE and RG transfer across the membrane was strongly accelerated, and in basic solution, all compounds were retained, mostly in the outer monolayer. In contrast, MACE flip-flop across the membrane remained very low even at pH 6. The protonation of ionizable groups is suggested to be a major determinant of chlorin transfer rates across the bilayer. pK(a) values of CE and RG were found to be between 6 and 8, and two of the carboxylate groups in MACE had pK(a) values below 6. For CE and RG, the kinetic profiles at acidic pH indicated that the initial fast membrane distribution was followed by secondary steps that are discussed in this article.

One-Step (18)F-Labeling of Carbohydrate-Conjugated Octreotate-Derivatives Containing a Silicon-Fluoride-Acceptor (SiFA): In Vitro and in Vivo Evaluation as Tumor Imaging Agents for Positron Emission Tomography (PET)

The synthesis, radiolabeling, and initial evaluation of new silicon-fluoride acceptor (SiFA) derivatized octreotate derivatives is reported. So far, the main drawback of the SiFA technology for the synthesis of PET-radiotracers is the high lipophilicity of the resulting radiopharmaceutical. Consequently, we synthesized new SiFA-octreotate analogues derivatized with Fmoc-NH-PEG-COOH, Fmoc-Asn(Ac?AcNH-?-Glc)-OH, and SiFA-aldehyde (SIFA-A). The substances could be labeled in high yields (38 ± 4%) and specific activities between 29 and 56 GBq/?mol in short synthesis times of less than 30 min (e.o.b.). The in vitro evaluation of the synthesized conjugates displayed a sst2 receptor affinity (IC?? = 3.3 ± 0.3 nM) comparable to that of somatostatin-28. As a measure of lipophilicity of the conjugates, the log P(ow) was determined and found to be 0.96 for SiFA-Asn(AcNH-?-Glc)-PEG-Tyr³-octreotate and 1.23 for SiFA-Asn(AcNH-?-Glc)-Tyr³-octreotate, which is considerably lower than for SiFA-Tyr³-octreotate (log P(ow) = 1.59). The initial in vivo evaluation of [¹?F]SiFA-Asn(AcNH-?-Glc)-PEG-Tyr³-octreotate revealed a significant uptake of radiotracer in the tumor tissue of AR42J tumor-bearing nude mice of 7.7% ID/g tissue weight. These results show that the high lipophilicity of the SiFA moiety can be compensated by applying hydrophilic moieties. Using this approach, a tumor-affine SiFA-containing peptide could successfully be used for receptor imaging for the first time in this proof of concept study.

Pooled analysis of trials comparing titanium-nitride-oxide-coated stents with paclitaxel-eluting stents in patients undergoing coronary stenting

We performed a pooled analysis of three trials comparing titanium-nitride-oxide-coated bioactive stents (BAS) with paclitaxel-eluting stents (PES) in 1,774 patients. All patients were followed for 12 months. The primary outcomes of interest were recurrent myocardial infarction (MI), death and target lesion revascularization (TLR). Secondary endpoints were stent thrombosis (ST) and major adverse cardiac events (MACE) including MI, death and TLR. There were 922 patients in the BAS group and 852 in the PES group. BAS significantly reduced the risk of recurrent MI (2.7% vs. 5.6%; risk ratio 0.50, 95% CI 0.31-0.81; p = 0.004) and MACE (8.9% vs. 12.6%; risk ratio 0.71, 95% CI 0.54-0.94; p = 0.02) during the 12 months of follow up. In contrast, the differences between BAS and PES were not statistically significant with respect to TLR (risk ratio 0.98, 95% CI 0.68-1.41), death (risk ratio 0.96, 95% CI 0.61-1.51) and definite ST (risk ratio 0.28, 95% CI 0.05-1.47). In conclusion, the results of this analysis suggest that BAS is effective in reducing TLR and improves clinical outcomes by reducing MI and MACE compared with PES.

Five-Year Clinical and Angiographic Outcomes of a Randomized Comparison of Sirolimus-Eluting and Paclitaxel-Eluting Stents: Results of the Sirolimus-Eluting Versus Paclitaxel-Eluting Stents for Coronary Revascularization LATE Trial

Background—Long-term comparative data of first-generation drug-eluting stents are scarce. We investigated clinical and angiographic outcomes of sirolimus-eluting (SES) and paclitaxel-eluting stents (PES) at 5 years as part of the Sirolimus-Eluting Versus Paclitaxel-Eluting Stents for Coronary Revascularization (SIRTAX) LATE study. Methods and Results—A total of 1012 patients were randomly assigned to SES or PES. Repeat angiography was completed in 444 of 1012 patients (43.8%) at 5 years. Major adverse cardiac events occurred in 19.7% of SES- and 21.4% of PES-treated patients (hazard ratio, 0.89; 95% confidence interval, 0.68 to 1.17; P=0.39) at 5 years. There were no differences between SES and PES in terms of cardiac death (5.8% versus 5.7%; P=0.35), myocardial infarction (6.6% versus 6.9%; P=0.51), and target lesion revascularization (13.1% versus 15.1%; P=0.29). Between 1 and 5 years, the annual rate of target lesion revascularization was 2.0% (95% confidence interval, 1.4% to 2.6%) for SES and 1.4% (95% confidence interval, 0.9% to 2.0%) for PES. Among patients undergoing paired angiography at 8 months and 5 years, delayed lumen loss amounted to 0.37±0.73 mm for SES and 0.29±0.59 mm for PES (P=0.32). The overall rate of definite stent thrombosis was 4.6% for SES and 4.1% for PES (P=0.74), and very late definite stent thrombosis occurred at an annual rate of 0.65% (95% confidence interval, 0.40% to 0.90%). Conclusions—Long-term follow-up of first-generation drug-eluting stents shows no significant differences in clinical and angiographic outcomes between SES and PES. The continuous increase in late lumen loss in conjunction with the ongoing risk of very late stent thrombosis suggests that vascular healing remains incomplete up to 5 years after implantation of first-generation drug-eluting stents.

Sirolimus versus paclitaxel coronary stents in clinical practice

Objectives: We aimed at comparing the long term clinical outcome of SES and PES in routine clinical practice. Background: Although sirolimus-eluting stents (SES) more effectively reduce neointimal hyperplasia than paclitaxel-eluting stents (PES), uncertainty prevails whether this difference translates into differences in clinical outcomes outside randomized controlled trials with selected patient populations and protocol-mandated angiographic follow-up. Methods: Nine hundred and four consecutive patients who underwent implantation of a drug-eluting stent between May 2004 and February 2005: 467 patients with 646 lesions received SES, 437 patients with 600 lesions received PES. Clinical follow-up was obtained at 2 years without intervening routine angiographic follow-up. The primary endpoint was a composite of death, myocardial infarction (MI), or target vessel revascularization (TVR). Results: At 2 years, the primary endpoint was less frequent with SES (12.9%) than PES (17.6%, HR = 0.70, 95% CI 0.50–0.98, P = 0.04). The difference in favor of SES was largely driven by a lower rate of target lesion revascularisation (TLR; 4.1% vs. 6.9%, P = 0.05), whereas rates of death (6.4% vs. 7.6%, P = 0.49), MI (1.9% vs. 3.2%, P = 0.21), or definite stent thrombosis (0.6% vs. 1.4%, P = 0.27) were similar for both stent types. The benefit regarding reduced rates of TLR was significant in nondiabetic (3.6% vs. 7.1%, P = 0.04) but not in diabetic patients (5.6% vs. 6.1%, P = 0.80). Conclusions: SES more effectively reduced the need for repeat revascularization procedures than PES when used in routine clinical practice. The beneficial effect is maintained up to 2 years and may be less pronounced in diabetic patients.

SYNTAX score and Clinical SYNTAX score as predictors of very long-term clinical outcomes in patients undergoing percutaneous coronary interventions: a substudy of SIRolimus-eluting stent compared with pacliTAXel-eluting stent for coronary revascularization (SIRTAX) trial

To investigate the ability of SYNTAX score and Clinical SYNTAX score (CSS) to predict very long-term outcomes in an all-comers population receiving drug-eluting stents.

Clinical long-term outcome after implantation of titanium nitride-oxide coated stents compared with paclitaxel- or sirolimus-eluting stents: propensity-score matched analysis

We performed a propensity score matched analysis to explore whether TiNOX stents are superior to paclitaxel- (PES) and sirolimus-eluting stents (SES) in routine clinical practice.

Long-term vascular healing in response to sirolimus- and paclitaxel-eluting stents: an optical coherence tomography study

This study sought to assess stent strut coverage, malapposition, protrusion, and coronary evaginations as markers of healing 5 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES), by optical coherence tomography (OCT).

The ω3-polyunsaturated fatty acid derivatives AVX001 and AVX002 directly inhibit cytosolic phospholipase A(2) and suppress PGE(2) formation in mesangial cells

ω3-polyunsaturated fatty acids (ω3-PUFAs) are known to exert anti-inflammatory effects in various disease models although their direct targets are only poorly characterized.