Correlation between plasma total nitric oxide levels and cerebral vasospasm and clinical outcome in patients with aneurysmal subarachnoid hemorrhage in Indian population

Biomarkers in aneurysmal subarachnoid hemorrhage: A short review

Poor outcomes of aneurysmal subarachnoid hemorrhage (aSAH) can be the result of the initial catastrophic event or the many acute or delayed neurological complications. Recent evidence suggests that some molecules play a critical role in both events, through some unknown pathways involved. Understanding the role of these molecules in these events could allow to improve diagnostic accuracy, guide management, and prevent long-term disability in aSAH. Here we present the studies on aSAH biomarkers present in current medical literature, highlighting their roles and main results.

Emerging Targets for Modulation of Immune Response and Inflammation in Stroke

The inflammatory and immunological responses play a significant role after stroke. The innate immune activation stimulated by microglia during stroke results in the migration of macrophages and lymphocytes into the brain and are responsible for tissue damage. The immune response and inflammation following stroke have no defined targets, and the intricacies of the immunological and inflammatory processes are only partially understood. Innate immune cells enter the brain and meninges during the acute phase, which can cause ischemia damage. Activation of systemic immunity is caused by danger signals sent into the bloodstream by injured brain cells, which is followed by a significant immunodepression that encourages life-threatening infections. Neuropsychiatric sequelae, a major source of post-stroke morbidity, may be induced by an adaptive immune response that is initiated by antigen presentation during the chronic period and is directed against the brain. Thus, the current review discusses the role of immune response and inflammation in stroke pathogenesis, their role in the progression of injury during the stroke, and the emerging targets for the modulation of the mechanism of immune response and inflammation that may have possible therapeutic benefits against stroke.

Cross-talk between the Ras GTPase and the Hog1 survival pathways in response to nitrosative stress in Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is a temperature-dependent dimorphic fungus that cause paracoccidioidomycosis (PCM), the major systemic mycosis in Latin America. The capacity to evade the innate immune response of the host is due to P. brasiliensis ability to respond and to survive the nitrosative stress caused by phagocytic cells. However, the regulation of signal transduction pathways associated to nitrosative stress response are poorly understood. Ras GTPase play an important role in the various cellular events in many fungi. Ras, in its activated form (Ras-GTP), interacts with effector proteins and can initiate a kinase cascade. In this report, we investigated the role of Ras GTPase in P. brasiliensis after in vitro stimulus with nitric oxide (NO). We observed that low concentrations of NO induced cell proliferation in P. brasiliensis, while high concentrations promoted decrease in fungal viability, and both events were reversed in the presence of a NO scavenger. We observed that high levels of NO induced Ras activation and its S-nitrosylation. Additionally, we showed that Ras modulated the expression of antioxidant genes in response to nitrosative stress. We find that the Hog1 MAP kinase contributed to nitrosative stress response in P. brasiliensis in a Ras-dependent manner. Taken together, our data demonstrate the relationship between Ras-GTPase and Hog1 MAPK pathway allowing for the P. brasiliensis adaptation to nitrosative stress.

The role of nitric oxide in stroke

Stroke is considered to be an acute cerebrovascular disease, including ischemic stroke and hemorrhagic stroke. The high incidence and poor prognosis of stroke suggest that it is a highly disabling and highly lethal disease which can pose a serious threat to human health. Nitric oxide (NO), a common gas in nature, which is often thought as a toxic gas, because of its intimate relationship with the pathological processes of many diseases, especially in the regulation of blood flow and cell inflammation. However, recent years have witnessed an increased interest that NO plays a significant and positive role in stroke as an essential gas signal molecule. In view of the fact that the neuroprotective effect of NO is closely related to its concentration, cell type and time, only in the appropriate circumstances can NO play a protective effect. The purpose of this review is to summarize the roles of NO in ischemic stroke and hemorrhagic stroke.

Effect of Metformin and Sitagliptin on Doxorubicin-Induced Cardiotoxicity in Rats: Impact of Oxidative Stress, Inflammation, and Apoptosis

Doxorubicin (DOX) is a widely used antineoplastic drug whose efficacy is limited by its cardiotoxicity. The aim of this study was to investigate the possible protective role of the antidiabetic drugs metformin (250 mg/kg dissolved in DW p.o. for seven days) and sitagliptin (10 mg/kg dissolved in DW p.o. for seven days) in a model of DOX-induced (single dose 15 mg/kg i.p. at the fifth day) cardiotoxicity in rats. Results of our study revealed that pretreatment with metformin or sitagliptin produced significant (P < 0.05) cardiac protection manifested by a significant decrease in serum levels of LDH and CK-MB enzymes and cardiac MDA and total nitrites and nitrates levels, a significant increase in cardiac SOD activity, and remarkable improvement in the histopathological features as well as a significant reduction in the immunohistochemical expression of COX-2, iNOS, and caspase-3 enzymes as compared to DOX group. These results may suggest using metformin and/or sitagliptin as preferable drugs for diabetic patients suffering from cancer and receiving DOX in their chemotherapy regimen.