Betatrophin is a recently identified hormone, the circulating concentrations of which are unaltered in human insulin resistance but correlate significantly with atherogenic lipid profiles in high-risk cohorts with morbid obesity or type 2 diabetes. Betatrophin could therefore be a novel pathomechanistic player in dysfunctional lipid metabolism associated with high cardiovascular risk.
Background and Aims
Sustained virologic response (SVR) to interferon (IFN)‐free therapies ameliorates portal hypertension (PH); however, it remains unclear whether a decrease in hepatic venous pressure gradient (HVPG) after cure of hepatitis C translates into a clinical benefit. We assessed the impact of pretreatment HVPG, changes in HVPG, and posttreatment HVPG on the development of hepatic decompensation in patients with PH who achieved SVR to IFN‐free therapy. Moreover, we evaluated transient elastography (TE) and von Willebrand factor to platelet count ratio (VITRO) as noninvasive methods for monitoring the evolution of PH.
Approach and Results
The study comprised 90 patients with HVPG ≥ 6 mm Hg who underwent paired HVPG, TE, and VITRO assessments before (baseline [BL]) and after (follow‐up [FU]) IFN‐free therapy. FU HVPG but not BL HVPG predicted hepatic decompensation (per mm Hg, hazard ratio, 1.18; 95% confidence interval, 1.08‐1.28; P < 0.001). Patients with BL HVPG ≤ 9 mm Hg or patients who resolved clinically significant PH (CSPH) were protected from hepatic decompensation. In patients with CSPH, an HVPG decrease ≥ 10% was similarly protective (36 months, 2.5% vs. 40.5%; P < 0.001) but was observed in a substantially higher proportion of patients (60% vs. 24%; P < 0.001). Importantly, the performance of noninvasive methods such as TE/VITRO for diagnosing an HVPG reduction ≥ 10% was inadequate for clinical use (area under the receiver operating characteristic curve [AUROC], < 0.8), emphasizing the need for HVPG measurements. However, TE/VITRO were able to rule in or rule out FU CSPH (AUROC, 0.86‐0.92) in most patients, especially if assessed in a sequential manner.
Conclusions
Reassessment of HVPG after SVR improved prognostication in patients with pretreatment CSPH. An “immediate” HVPG decrease ≥ 10% was observed in the majority of these patients and was associated with a clinical benefit, as it prevented hepatic decompensation. These results support the use of HVPG as a surrogate endpoint for interventions that lower portal pressure by decreasing intrahepatic resistance.
Phenytoin, an anticonvulsant, exhibits nonlinear pharmacokinetics with large interindividual differences. Because of its small therapeutic range with the risk of therapeutic failure or adverse drug effects in susceptible persons, therapeutic drug monitoring is frequently applied. The interindividual differences in dose response can partially be explained by known genetic polymorphisms in the metabolic enzyme CYP2C9 but a large deal of individual variability remains still unexplained. Part of this variability might be accounted for by variable uptake of phenytoin, which is a substrate of p-glycoprotein, encoded by the human MDR1 gene. We evaluated, whether phenytoin plasma levels correlate with a polymorphism in the MDR1 gene, C3435T, which is associated with intestinal PGP activity. Genotyping and analyses of plasma levels of phenytoin and metabolites in 96 healthy Turkish volunteers showed that the MDR1C Ͼ T3435 polymorphism affects phenytoin plasma levels (P = 0.064) and the metabolic ratio of p-HPPH vs phenytoin (MDR1*TT genotype, P = 0.026). The MDR1*CC genotype is more common in volunteers with low phenytoin levels (P Յ 0.001, 2 test). A combined analysis of variable alleles of CYP2C9, 2C19 and MDR1 revealed that the number of mutant CYP2C9 alleles is a major determinant, the number of MDR1*T alleles further contributes to the prediction of phenytoin plasma levels and CYP2C19*2 does not explain individual variability. The regression equation that fitted the data best included the number of mutant CYP2C9 and MDR*T alleles as predictory variables and explained 15.4% of the variability of phenytoin data (r 2 = 0.154, P = 0.0002). Furthermore, analysis of CYP2C9 and MDR1 genotypes in 35 phenytoin-treated patients recruited from therapeutic drug monitoring showed that combined CYP2C9 and MDR1 analysis has some predictive value not only in the controlled settings of a clinical trial, but also in the daily clinical practice.
Resveratrol is considered to have a number of beneficial effects. Recently, our group modified the molecule and synthesized a number of compounds with different biochemical effects. Polymethoxy and polyhydroxy derivatives of resveratrol were shown to inhibit tumor cell growth in various cell lines and inflammation pathways (cyclooxygenases activity), in part more effectively than resveratrol itself. One lead compound (hexahydroxystilbene, M8) turned out to be the most effective inhibitor of tumor cell growth and of cyclooxygenase 2 activity. M8 was then studied in two different human melanoma mouse models. This novel resveratrol analog was able to inhibit melanoma tumors in a primary tumor model alone and in combination with dacarbacine, an anticancer compound that is used for melanoma treatment. We also tested the development of lymph node metastasis in a second melanoma model and again M8 successfully inhibited the tumor as well as the size and weight of lymph node metastasis. Hydroxylated resveratrol analogs therefore represent a novel class of anticancer compounds and promising candidates for in vivo studies.
Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a compound found in wine and is held responsible for a number of beneficial effects of red wine. Besides the prevention of heart disease and significant anti-inflammatory effects, resveratrol might inhibit tumor cell growth and even play a role in the aging process. We here describe the structure-activity relationship of resveratrol and analogues of resveratrol regarding the free radical scavenging and antitumor effects of this exciting natural compound. In addition, we have synthesized a number of analogues of resveratrol with the aim to further improve the beneficial effects of resveratrol. Our studies were based on the analysis of structural properties, which were responsible for the most important effects of this compound. Striking in vivo effects can be observed with hexahydroxystilbene (M8), the most effective synthetic analogue of resveratrol. We could show that M8 inhibits tumor as well as metastasis growth of human melanoma in two different animal models, alone and in combination with dacarbacine.
Ribonucleotide reductase is the rate-limiting enzyme of DNA synthesis, and it has been shown to be linked with malignant transformation and tumor cell proliferation. It was therefore considered as an excellent target for cancer chemotherapy. This article reviews the in vitro and in vivo effects of hydroxyurea the first inhibitor of the enzyme, which is currently used in general clinical practice. In addition, we summarize the results obtained with other inhibitors of the enzyme; for instance, polyhydroxy-substituted benzohydroxamic acid derivatives, a promising group of inhibitors of ribonucleotide reductase that was synthesized by Bart van'T Riet and investigated by our group. In vitro as well as animal data and pharmacokinetic results are reviewed and possible implications for an improvement in the management of various patient groups are outlined.
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