Role of conventional therapies in the era of biological treatment in Crohn’s disease

Outstanding progress regarding the pathophysiology of Crohn’s disease (CD) has led to the development of innovative therapeutic concepts. Numerous controlled trials have been performed in CD. This review concentrates on the results of randomized,placebo-controlled trials,and meta-analyses when available,that provide the highest degree of evidence. Current guidelines on the management of CD recommend a step-up approach to treatment involving the addition of more powerful therapies as the severity of disease ...     

Use of the Crohn＇s disease activity index in clinical trials of biological agents

The Crohn＇s disease activity index （CDAI） has been commonly used to assess the effects of treatment with different agents in Crohn＇s disease （CD）. However, these studies may be compromised, if the results compared to a placebo or standard therapy group （in the absence of a placebo） substantially differ from the expected response. In addition, significant concerns have been raised regarding the reliability and validity of the CDAI. Reproducibility of the CDAI may be limited as significant inter-observer error has been recorded, even if measurements are done by experienced clinicians with expertise in the diagnosis and treatment of CD. Finally, many CDAI endpoints are open to subjective interpretation and have the potential for manipulation. This is worrisome as there is the potential for significant financial gain, if the results of a clinical trial appear to provide a positive result. Physicians caring for patients should be concerned about the positive results in clinical trials that are sponsored by industry, even if the trials involve respected centers and the results appear in highly ranked medical journals.     

Anal ulcerations in Crohn’s disease: Natural history in the era of biological therapy

BackgroundThe natural history of anal ulcerations in Crohn’s disease remains unknown.AimsTo assess the long-term outcomes of anorectal ulcerations.MethodsData from consecutive patients with perineal Crohn’s disease were prospectively recorded. The data of patients with anal ulceration were extracted.ResultsAnal ulcerations were observed in 154 of 282 patients (54.6%), and 77 cases involved cavitating ulcerations. The cumulative healing rates were 47%, 70% and 82% at 1, 2 and 3 years, respectively. Patients with a primary fistula phenotype had a shorter median time to healing of their anal ulceration (28 [13–83] weeks) than those with a stricture (81 [28–135] weeks) or those with isolated ulceration (74 [31–181] weeks) (p = 0.004). Among patients with ulcerations but no fistula at referral (n = 67), only 4 (6%) developed de novo abscesses and/or fistula during follow-up. There was no benefit associated with introducing or optimising biologics, nor with combining immunosuppressants and biologics.ConclusionAnal ulceration in Crohn’s disease usually requires a long time to achieve sustained healing. Determining the impact of biologics on healing rates will require dedicated randomised trials although it does not show a significant healing benefit in the present study.     

Unveiling the biological role of sphingosine-1-phosphate receptor modulators in inflammatory bowel diseases

Inflammatory bowel disease(IBD) is chronic inflammation of the gastrointestinal tract that has a high epidemiological prevalence worldwide. The increasing disease burden worldwide, lack of response to current biologic therapeutics, and treatment-related immunogenicity have led to major concerns regarding the clinical management of IBD patients and treatment efficacy. Understanding disease pathogenesis and disease-related molecular mechanisms is the most important goal in developing new and effec...     

The first results of the “bevolkingsonderzoek” in the Zaanstreek region in The Netherlands

This short communication describes the results with respect to stage of colorectal cancer in people detected via screening and patients with clinical complaints.     

Analysis of biological properties of selected elements of haemostasis after treatment with the oxidized form of homocysteine in vitro

The elevated level of homocysteine (Hcys; hyperhomocysteinemia, in relation to the total plasma Hcys concentration, >15?μM) is associated with different diseases in human, including cardiovascular diseases. In plasma, Hcys occurs in various forms (the reduced Hcys, the oxidized Hcys, homocysteine thiolactone (HTL) and a component of proteins as a result of N- or S-homocysteinylation). The mechanisms by which hyperhomocysteinemia contributes to changes of haemostasis are complex and unclear. The role of different forms of Hcys, which may be involved in the modulation of haemostatic process during hyperhomocysteinemia is also not yet well-known. Our previous works have shown that both Hcys in the reduced form and the most reactive form of Hcys-its thiolactone may modify fibrinolysis, coagulation process and biological activity of blood platelets. The mechanism by which the oxidized Hcys exerts the prothrombotic effect and influences on blood platelets or plasma remains unclear. The aim of our study in?vitro was to establish and compare the influence of the oxidized Hcys (at final doses of 0.01-1?mM), the reduced Hcys (at final doses of 0.01-1?mM) and HTL (at final doses of 0.1-1?μM) on selected haemostatic properties of blood platelets (platelet aggregation and platelet microparticle formation measured by flow cytometry) and plasma (fibrin polymerization and lysis). Here, our results indicate that the oxidized Hcys, like the reduced Hcys or HTL-augmented blood platelet aggregation, stimulated polymerization of fibrinogen and reduced the fibrin lysis in plasma. But, we suggest that the most reactive form of Hcys may be HTL (at lower concentrations than Hcys) during hyperhomocysteinemia-induced cardiovascular diseases.     

Gonadotropin-releasing hormone analogs in fertility preservation-lack of biological basis?

In this Practice Point commentary, we discuss the results and limitations of a nonrandomized, retrospective-prospective study of gonadotropin-releasing hormone analogs (GnRHa) in women with Hodgkin disease. Blumenfeld et al. concluded that coadministration of GnRHa during chemotherapy preserved cyclic ovarian function but not fertility. As the endocrine and ovulatory functions of the ovary are connected, this conclusion seems implausible. The study did not control for disease severity or the dose of alkylating agents. In addition, GnRHa treatment was not randomized, so patients in the control group were unlikely to have received GnRHa because the severity of their disease resulted in more-aggressive chemotherapy. By contrast, the only randomized study published to date showed no gonadal protection from GnRHa during chemotherapy in either sex. Furthermore, GnRHa did not prevent primordial-follicle loss in a human ovarian xenograft model. Unless a larger prospective study proves otherwise, GnRHa should not be offered as a proven method of fertility preservation.     

Importance of the DNA “bond” in programmable nanoparticle crystallization

If a solution of DNA-coated nanoparticles is allowed to crystallize, the thermodynamic structure can be predicted by a set of structural design rules analogous to Pauling’s rules for ionic crystallization. The details of the crystallization process, however, have proved more difficult to characterize as they depend on a complex interplay of many factors. Here, we report that this crystallization process is dictated by the individual DNA bonds and that the effect of changing structural or environmental conditions can be understood by considering the effect of these parameters on free oligonucleotides. Specifically, we observed the reorganization of nanoparticle superlattices using time-resolved synchrotron small-angle X-ray scattering in systems with different DNA sequences, salt concentrations, and densities of DNA linkers on the surface of the nanoparticles. The agreement between bulk crystallization and the behavior of free oligonucleotides may bear important consequences for constructing novel classes of crystals and incorporating new interparticle bonds in a rational manner.Materials scientists have accomplished much by studying the way atoms and molecules crystallize. In these systems, however, the identity of the atom and its bonding behavior cannot be independently controlled, limiting our ability to tune material properties at will. In contrast, when a nanoparticle is modified with a dense shell of upright, oriented DNA, it can behave as a programmable atom equivalent (PAE) (1, 2) that can be used to synthesize diverse crystal structures with independent control over composition, scale, and lattice symmetry (3–14). The thermodynamic product of this crystallization process has been extensively studied by both experimental and theoretical means, and thus a series of design rules has been proposed and validated with a simple geometric model known as the complementary contact model (CCM). These rules allow one to predict the thermodynamically favored structure as the arrangement of particles that maximizes complementary contacts and therefore DNA hybridization (2, 6). These efforts have been very successful in predicting the thermodynamically favored product; recent studies have even demonstrated that PAEs can form single-crystal Wulff polyhedra that are analogous to those formed in atomic systems with the same crystallographic symmetry (15). However, the fact that there is a crystalline thermodynamic product does not mean that any choice of DNA and nanoparticles will result in crystalline systems in practice (3, 4). For example, crystallization has been observed for a relatively narrow class of PAEs (16) and in a manner that is primarily dependent upon the length of the DNA linker and temperature at which assembly occurs (8). Thus, absent from our understanding of these systems is a connection between the crystallization process and the properties of the DNA bonds that form the foundation of these structures.Here, we study the crystallization process and find that the complexity of the polyvalent DNA interactions can be simply understood by considering the behavior of a single DNA bond. By systematically studying the roles of nucleobase sequence, solution ionic strength, DNA density, and temperature on crystallization, we find that the effects of these factors are mirrored by the rates of hybridization and dehybridization of free DNA. In addition to examining steady-state structures, we evaluate the formation and reorganization of these crystals in a time-resolved manner using small-angle X-ray scattering (SAXS) to study how crystallization dynamics are affected by each design variable. Finally, we develop a predictive model that allows one to compare the range of temperatures over which crystallization will occur for different conditions. In addition to providing an avenue for improving PAE crystallization and realizing new architectures, the effectiveness of this reductionist model suggests that this approach can be applied to study crystallization in a broader class of systems, thus making an impact in the materials by design community.     

Medical prophylaxis: the value of an “opt in” policy

Medical thromboprophylaxis reduces venous thromboembolism (VTE), while causing bleeding. Routine application of pharmacological VTE prophylaxis to low risk medical patients is likely to cause net harm; as a result only moderate or high risk patients should be exposed to VTE prophylaxis. To avoid unneeded exposure to VTE prophylaxis health care providers should use an “opt-in” policy which does not default to the use of VTE prophylaxis in inappropriate patients.     

“Real-time” obstacle avoidance in the absence of primary visual cortex

When we reach toward objects, we easily avoid potential obstacles located in the workspace. Previous studies suggest that obstacle avoidance relies on mechanisms in the dorsal visual stream in the posterior parietal cortex. One fundamental question that remains unanswered is where the visual inputs to these dorsal-stream mechanisms are coming from. Here, we provide compelling evidence that these mechanisms can operate in “real-time” without direct input from primary visual cortex (V1). In our first experiment, we used a reaching task to demonstrate that an individual with a dense left visual field hemianopia after damage to V1 remained strikingly sensitive to the position of unseen static obstacles placed in his blind field. Importantly, in a second experiment, we showed that his sensitivity to the same obstacles in his blind field was abolished when a short 2-s delay (without vision) was introduced before reach onset. These findings have far-reaching implications, not only for our understanding of the time constraints under which different visual pathways operate, but also in relation to how these seemingly “primitive” subcortical visual pathways can control complex everyday behavior without recourse to conscious vision.     

Foraging success of biological Lévy flights recorded in situ

It is an open question how animals find food in dynamic natural environments where they possess little or no knowledge of where resources are located. Foraging theory predicts that in environments with sparsely distributed target resources, where forager knowledge about resources' locations is incomplete, Lévy flight movements optimize the success of random searches. However, the putative success of Lévy foraging has been demonstrated only in model simulations. Here, we use high-temporal-resolution Global Positioning System (GPS) tracking of wandering (Diomedea exulans) and black-browed albatrosses (Thalassarche melanophrys) with simultaneous recording of prey captures, to show that both species exhibit Lévy and Brownian movement patterns. We find that total prey masses captured by wandering albatrosses during Lévy movements exceed daily energy requirements by nearly fourfold, and approached yields by Brownian movements in other habitats. These results, together with our reanalysis of previously published albatross data, overturn the notion that albatrosses do not exhibit Lévy patterns during foraging, and demonstrate that Lévy flights of predators in dynamic natural environments present a beneficial alternative strategy to simple, spatially intensive behaviors. Our findings add support to the possibility that biological Lévy flight may have naturally evolved as a search strategy in response to sparse resources and scant information.     

Expression and biological role of δ-catenin in human ovarian cancer

Objective

δ-Catenin is found to be involved in the progression of several human cancers. However, its expression pattern and biological roles in human ovarian cancers are not clear. In this study, we examined the expression pattern of δ-catenin in 149 ovarian cancer specimens. We also depleted and overexpressed δ-catenin expression in ovarian cancer cell lines and investigated its role in cell proliferation and invasion.

Methods

δ-Catenin expression was analyzed in 149 archived ovarian cancer specimens using immunohistochemistry. siRNA knockdown and plasmid transfection were performed in SKOV3, SW626, and OVCAR3 cell lines. MTT, colony formation assay, soft agar colony assay, and matrigel invasion assay were carried out to assess the role of δ-catenin in cell proliferation and invasion. We also performed cell cycle analysis in δ-catenin depleted and overexpressed cells. In addition, we examined the level of several cell cycle-related molecules using Western blot.

Results

Of the 149 patients in the study, 104 (69.7?%) showed δ-catenin overexpression. δ-catenin overexpression positively correlated with advanced FIGO stage. δ-Catenin depletion in ovarian cancer cell lines inhibited ovarian cancer cell proliferation and invasion. Depletion of δ-catenin also blocked cell cycle progression and downregulated cyclin D1 expression in ovarian cancer cells. Overexpression of δ-catenin enhanced cell proliferation, invasion, and upregulated cyclinD1 expression.

Conclusions

δ-Catenin is overexpressed in ovarian cancers and associated with advanced stage. Our data provide evidence that δ-catenin regulates the ovarian cancer cell proliferation, invasion, and cell cycle. δ-Catenin thus has potential as a therapeutic target.     

Determinants of Achieved LDL Cholesterol and “Non-HDL” Cholesterol in the Management of Dyslipidemias

Purpose of Review

The advent of combination therapy to provide LDL lowering beyond that achieved with statins necessitates the development of greater understanding of how drugs work together, what changes occur in key lipoprotein fractions, and what residual risk remains.

Recent Findings

Clinical trials of agents that, when added to statins, generate profound LDL lowering have been successful in reducing further the risk of cardiovascular disease. LDL cholesterol can be now decreased to unprecedented levels, so the focus of attention then shifts to other apolipoprotein B-containing, atherogenic lipoprotein classes such as lipoprotein(a) and remnants of the metabolism of triglyceride-rich particles. “Non-HDL cholesterol” is used increasingly (especially if measured in the non-fasting state) as a more comprehensive index of risk.

Summary

Metabolic studies reveal how current drugs act in combination to achieve profound lipid lowering. However, care is needed in interpreting achieved LDLc and non-HDLc levels in the emerging treatment paradigm.

     

Risks and benefits of combining immunosuppressives and biological agents in inflammatory bowel disease: is the synergy worth the risk?

Since the introduction of infliximab to treat Crohn's disease, combination therapy with immunosuppressants has reduced immunogenicity, without impacting efficacy. The availability of novel anti-TNF agents and potential combined toxicities question the risk/benefit of combination therapies.