Involvement of new oxidative stress markers in chronic spontaneous urticaria.

INTRODUCTION: Oxidative stress is a result of an imbalance between endogenous production of free reactive oxygen species and reduced effectiveness of antioxidant defence mechanisms. Advanced glycation end products (AGEs) and advanced oxidation protein products (AOPPs) are compounds formed by transformation of macromolecules, including proteins which can serve as markers of oxidative stress and inflammation in several diseases. AIM: To investigate the role of AGEs and AOPPs as new markers of oxidative stress and inflammation in patients with chronic spontaneous urticaria (CSU). MATERIAL AND METHODS: Advanced glycation end products and AOPP levels were determined in the sera of 85 patients with CSU and 64 healthy controls, using spectrofluorimetry and spectrophotometry, respectively. RESULTS: Advanced oxidation protein products levels in patients were statistically higher than those in controls. These levels were not affected by the presence of positive autologous serum test results or autologous plasma test results. No statistically significant differences were found between AGE levels in patients and controls. CONCLUSIONS: Formation of AGEs and AOPPs may be accelerated in immunological and allergic disorders. Depending on the sites evaluated, the presence or absence of oxidative stress in chronic urticaria is controversial. To our knowledge, this is the first study showing the possible involvement of AOPPs in CSU. The different behaviour observed for these two biomarkers is very likely due to the activation of specific related biochemical pathways associated with the condition under study.

Preclinical studies in support of defibrotide for the treatment of multiple myeloma and other neoplasias.

PURPOSE OF THE STUDY: Defibrotide, an orally bioavailable polydisperse oligonucleotide, has promising activity in hepatic veno-occlusive disease, a stem cell transplantation-related toxicity characterized by microangiopathy. The antithrombotic properties of defibrotide and its minimal hemorrhagic risk could serve for treatment of cancer-associated thrombotic complications. Given its cytoprotective effect on endothelium, we investigated whether defibrotide protects tumor cells from cytotoxic antitumor agents. Further, given its antiadhesive properties, we evaluated whether defibrotide modulates the protection conferred to multiple myeloma cells by bone marrow stromal cells. METHODS-RESULTS: Defibrotide lacks significant single-agent in vitro cytotoxicity on multiple myeloma or solid tumor cells and does not attenuate their in vitro response to dexamethasone, bortezomib, immunomodulatory thalidomide derivatives, and conventional chemotherapeutics, including melphalan and cyclophosphamide. Importantly, defibrotide enhances in vivo chemosensitivity of multiple myeloma and mammary carcinoma xenografts in animal models. In cocultures of multiple myeloma cells with bone marrow stromal cells in vitro, defibrotide enhances the multiple myeloma cell sensitivity to melphalan and dexamethasone, and decreases multiple myeloma-bone marrow stromal cell adhesion and its sequelae, including nuclear factor-kappaB activation in multiple myeloma and bone marrow stromal cells, and associated cytokine production. Moreover, defibrotide inhibits expression and/or function of key mediators of multiple myeloma interaction with bone marrow stromal cell and endothelium, including heparanase, angiogenic cytokines, and adhesion molecules. CONCLUSION: Defibrotide's in vivo chemosensitizing properties and lack of direct in vitro activity against tumor cells suggest that it favorably modulates antitumor interactions between bone marrow stromal cells and endothelia in the tumor microenvironment. These data support clinical studies of defibrotide in combination with conventional and novel therapies to potentially improve patient outcome in multiple myeloma and other malignancies.

Acute hypertension induces oxidative stress in brain tissues.

Arterial hypertension is not only a major risk factor for cerebrovascular accidents, such as stroke and cerebral hemorrhage, but is also associated to milder forms of brain injury. One of the main causes of neurodegeneration is the increase in reactive oxygen species (ROS) that is also a common trait of hypertensive conditions, thus suggesting that such a mechanism could play a role even in the onset of hypertension-evoked brain injury. To investigate this issue, we have explored the effect of acute-induced hypertensive conditions on cerebral oxidative stress. To this aim, we have developed a mouse model of transverse aortic coarctation (TAC) between the two carotid arteries, which imposes acutely on the right brain hemisphere a dramatic increase in blood pressure. Our results show that hypertension acutely induced by aortic coarctation induces a breaking of the blood-brain barrier (BBB) and reactive astrocytosis through hyperperfusion, and evokes trigger factors of neurodegeneration such as oxidative stress and inflammation, similar to that observed in cerebral hypoperfusion. Moreover, the derived brain injury is mainly localized in selected brain areas controlling cognitive functions, such as the cortex and hippocampus, and could be a consequence of a defect in the BBB permeability. It is noteworthy to emphasize that, even if these latter events are not enough to produce ischemic/hemorrhagic injury, they are able to alter mechanisms fundamental for maintaining normal brain function, such as protein synthesis, which has a prominent role for memory formation and cortical plasticity.

C1-inhibitor protects against brain ischemia-reperfusion injury via inhibition of cell recruitment and inflammation.

Previous studies demonstrated that C1-inhibitor (C1-INH), a complement and contact-kinin systems inhibitor, is neuroprotective in cerebral ischemia. To investigate the mechanism of this action, we evaluated the expression of neurodegeneration and inflammation-related factors in mice subjected to 2-h ischemia and 2 or 46 h reperfusion. C1-INH significantly dampened the mRNA expression of the adhesion molecules P-selectin and ICAM-1 induced by the ischemic insult. It significantly decreased the pro-inflammatory cytokine (TNF alpha, IL-18) and increased the protective cytokine (IL-6, IL-10) gene expression. C1-INH treatment prevented the decrease of NFH gene, a marker of cellular integrity and counteracted the increase of pro-caspase 3, an apoptosis index. Furthermore, C1-INH markedly inhibited the activation and/or recruitment of microglia/macrophage, as shown by immunohistochemistry. In conclusion, C1-INH exerts an anti-inflammatory and anti-apoptotic action on ischemia-reperfusion injury. Our present and past data support a major effect of C1-INH on cell recruitment from the vasculature to the ischemic site.

Peripheral treatment with enoxaparin, a low molecular weight heparin, reduces plaques and beta-amyloid accumulation in a mouse model of Alzheimer's disease.

We investigated the effect of long-term, peripheral treatment with enoxaparin, a low molecular weight heparin, in transgenic mice overexpressing human amyloid precursor protein(751). Enoxaparin (6 IU per mouse intraperitoneally, three times a week for 6 months) significantly lowered the number and the area occupied by cortical beta-amyloid deposits and the total beta-amyloid (1-40) cortical concentration. Immunocytochemical analysis of glial fibrillary acid protein-positive cells showed that enoxaparin markedly reduced the number of activated astrocytes surrounding beta-amyloid deposits. In vitro, the drug dose-dependently attenuated the toxic effect of beta-amyloid on neuronal cells. Enoxaparin dose-dependently reduced the ability of beta-amyloid to activate complement and contact systems, two powerful effectors of inflammatory response in AD brain. By reducing the beta-amyloid load and cytotoxicity and proinflammatory activity, enoxaparin offers promise as a tool for slowing the progression of Alzheimer's disease.