Current Medicinal Chemistry - Volume 23, Issue 39, 2016

In clinical and experimental settings, a great deal of effort is being made to protect cells and tissues against harmful conditions and to facilitate metabolic recovery following these insults. Much of the recent attention has focused on the protective role of a natural form of sugar, fructose 1,6-bisphosphate (F16bP). F16bP is a high-energy glycolytic intermediate that has been shown to exert a protective action in different cell types and tissues (including the brain, kidney, intestine, liver and heart) against various harmful conditions. For example, there is much evidence that it prevents neuronal damage due to hypoxia and ischemia. Furthermore, the cytoprotective effects of F16bP have been documented in lesions caused by chemicals or cold storage, in a decrease in mortality during sepsis shock and even in the prevention of bone loss in experimental osteoporosis. Intriguingly, protection in such a variety of targets and animal models suggests that the mechanisms induced by F16bP are complex and involve different pathways. In this review we will discuss the most recent theories concerning the molecular model of action of F16bP inside cells. These include its incorporation as an energy substrate, the mechanism for the improvement of ATP availability, and for preservation of organelle membrane stability and functionality. In addition we will present new evidences regarding the capacity of F16bP to decrease oxidative stress by limiting free radical production and improving antioxidant systems, including the role of nitric oxide in the protective mechanism induced by F16bP. Finally we will review the proposed mechanisms for explaining its anti-inflammatory, immunomodulatory and neuroprotective properties.

Background: Bioactive plant secondary metabolites have complex chemical structures, which are specific to each plant species/family, and accumulate in tiny amounts. The growing market demand for many phytochemicals can lead to the over-harvesting of medicinal plants in their natural habitat, endangering species in the process. Objective: An ongoing challenge for our society is therefore to develop a bio-sustainable production of phytochemicals, among other natural resources. Cancer is currently a major health problem, responsible for approximately 8.2 million deaths per year worldwide. We therefore focused this review on cancer therapeutic agents from plants and their biotechnological production. Method and Results: An extensive review of the literature shows that although a wide range of phytochemicals have demonstrated anti-proliferative activity in vitro, only a few examples of plant-based drugs are included in the Anatomical Therapeutic Chemical (ATC) classification as antineoplastic agents. These include vinca alkaloids and their derivatives (L01CA), podophyllotoxin derivatives (L01CB), and paclitaxel and its derivatives (L01CD), as well as camptothecin derivatives (L01XX). These compounds all have in common a complex chemical structure, a scarce distribution in nature, and a high added value. After describing the chemical structures, natural sources and biological activities of these anticancer compounds, we focus on the state of the art in their biotechnological production in plant cell biofactories. Conclusion: More in-depth studies are required on the biosynthesis of target plant metabolites and its regulation in order to increase their biotechnological production in plant cell factories and ultimately implement these biosustainable processes at an industrial level.

Background: Although mucositis, diarrhea, and constipation as well as immunosuppression are well recognized side-effects of cancer treatment, the underlying mechanisms including changes in the composition of gut microbiota and Clostridium difficile infection have not yet been thoroughly reviewed. Objective: We herein set out to review the literature regarding the relations between cancer chemotherapy, radiation treatment, and Clostridium difficile-associated colitis. Method: Review of the English language literature published from 2008 to 2015 on the association between cancer chemotherapy, radiation treatment, and C. difficile-associated colitis. Results: Certain chemotherapeutic combinations, mainly those containing paclitaxel, are more likely to be followed by C. difficile infection (CDI), while some tumor types are more likely to be complicated by CDI following chemotherapy. CDI following irradiation occurs mostly in patients who were treated for cancer in the head and neck area. Risk factors found were proton pump inhibitors, antibiotics, cytostatic agents, and tube feeding. The drug of choice for an initial episode of mild-to-moderate CDI is metronidazole, whereas vancomycin is reserved for an initial episode of severe CDI. Fidaxomycin is another option for treatment of severe CDI, with fewer recurrences. Conclusion: The influence of CDI on the treatment of oncological patients is not fully acknowledged. Infection with C. difficile is more frequent in those patients treated by antibiotics simultaneously with chemotherapy. Aggressive supportive care with intravenous hydration, antibiotics, and close surgical monitoring for selective intervention can significantly decrease the morbidity and life-threatening complications associated with this infection.

This article reviews the use of silica, alumina and calcium phosphate-based nanostructured materials with biomedical applications. A short introduction on the use of the materials in Science, Nanotechnology and Health is included followed by a revision of each of the selected materials. A description of the principal synthetic methods used in the preparation of the materials in nanostructured form is included. The most widely used applications in biomedicine are reviewed including, for example drug-delivery, bone regeneration, imaging, sensoring amongst others. Finally, a short description of the toxicity and cytotoxicity associated with each of the materials of this revision is presented. This short literature revision serves to demonstrate the very promising future ahead of nanosystems based on silica, alumina and calcium phosphate for biological and biomedical applications.

Orally administered drugs must pass through the intestinal wall and then through the liver before reaching systemic circulation. During this process drugs are subjected to different processes that may determine the therapeutic value. The intestinal barrier with active drug metabolizing enzymes and drug transporters in enterocytes plays an important role in the determination of drug bioavailability. Accumulating information demonstrates variable distribution of drug metabolizing enzymes and transporters along the human gastrointestinal tract (GI), that creates specific barrier characteristics in different segments of the GI. In this review, expression of drug metabolizing enzymes and transporters in the healthy and diseased human GI as well as their regulatory aspects: genetic, miRNA, DNA methylation are outlined. The knowledge of unique interplay between drug metabolizing enzymes and transporters in specific segments of the GI tract allows more precise definition of drug release sites within the GI in order to assure more complete bioavailability and prediction of drug interactions.

Background: Plasma homocysteine is an independent non-traditional risk factor for atherosclerotic cardiovascular disease. The impact of statin therapy on plasma homocysteine is not conclusive. Objective: To evaluate the effect of statin therapy on plasma homocysteine concentrations in a systematic review and meta-analysis of controlled clinical trials. The secondary aim was to assess the comparative effect of statins versus fibrates on plasma homocysteine levels in head-to-head trials. Method: PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from the first reports to March 07, 2016) to identify controlled trials evaluating the impact of statins on plasma homocysteine concentrations. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random-effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderators. Results: Meta-analysis of data from 7 studies did not suggest a significant alteration in plasma homocysteine concentrations following treatment with statins compared with the control group (WMD: -0.59 μmol/L, 95% CI: -1.66, 0.48, p=0.279; I2=52.53%). However, meta-analysis of 9 studies suggested a significantly greater reduction of plasma homocysteine concentrations with statins compared with fenofibrate (WMD: -4.81 μmol/L, 95% CI: -5.39, -4.23, p<0.001; I2=0%). Results of both analyses were robust in the sensitivity analysis. Conclusion: Statin therapy is not associated with a significant alteration of plasma homocysteine levels, while fenofibrate increases the homocysteine levels when compared with statins.