SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Ischemia

334

 To quantify the dose-response associations between total physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke events.

Concepts: Cancer, Breast cancer, Hypertension, Obesity, Stroke, Heart disease, Ischemia, Ischaemic heart disease

322

Depressive disorders were a leading cause of burden in the Global Burden of Disease (GBD) 1990 and 2000 studies. Here, we analyze the burden of depressive disorders in GBD 2010 and present severity proportions, burden by country, region, age, sex, and year, as well as burden of depressive disorders as a risk factor for suicide and ischemic heart disease.

Concepts: Death, Risk, 1920, Heart disease, Ischemia, Major depressive disorder, Ischaemic heart disease, 1922

253

Percutaneous coronary intervention (PCI) relieves angina in patients with stable ischemic heart disease, but clinical trials have not shown that it improves survival. Between June 1999 and January 2004, we randomly assigned 2287 patients with stable ischemic heart disease to an initial management strategy of optimal medical therapy alone (medical-therapy group) or optimal medical therapy plus PCI (PCI group) and did not find a significant difference in the rate of survival during a median follow-up of 4.6 years. We now report the rate of survival among the patients who were followed for up to 15 years.

Concepts: Medicine, Cardiology, Ischemia

172

The incidence of Alzheimer’s disease increases in people who have had an ischemic episode. Furthermore, APP expression is increased following ischemic or hypoxic conditions, as is the production of the Aβ peptide. To address the question of why APP and Aβ are increased in hypoxic and ischemic conditions we induced an ischemic episode in APP knockout mice (APP-/-) and BACE1 knockout mice (BACE-/-). We find that both APP-/- and BACE-/- mice have a dramatically increased risk of mortality as a result of cerebral ischemia. Furthermore, APP knockout mice have reduced cerebral blood flow in response to hypoxia, while wild-type mice maintain or increase cerebral blood flow to the same conditions. The transcription factor, serum response factor (SRF), and calcium-binding molecule, calsequestrin, both involved in vascular regulation, are significantly altered in the brains of APP-/- mice compared to wild type controls. These results show that APP regulates cerebral blood flow in response to hypoxia, and that it, and its cleavage fragments, are crucial for rapid adaptation to ischemic conditions.

Concepts: Alzheimer's disease, Gene, Gene expression, Stroke, Traumatic brain injury, Transcription factor, Ischemia, Hypoxia

170

Carbon monoxide (CO) at low concentrations imparts protective effects in numerous preclinical small animal models of brain injury. Evidence of protection in large animal models of cerebral injury, however, has not been tested. Neurologic deficits following open heart surgery are likely related in part to ischemia reperfusion injury that occurs during cardiopulmonary bypass surgery. Using a model of deep hypothermic circulatory arrest (DHCA) in piglets, we evaluated the effects of CO to reduce cerebral injury. DHCA and cardiopulmonary bypass (CPB) induced significant alterations in metabolic demands, including a decrease in the oxygen/glucose index (OGI), an increase in lactate/glucose index (LGI) and a rise in cerebral blood pressure that ultimately resulted in increased cell death in the neocortex and hippocampus that was completely abrogated in piglets preconditioned with a low, safe dose of CO. Moreover CO-treated animals maintained normal, pre-CPB OGI and LGI and corresponding cerebral sinus pressures with no change in systemic hemodynamics or metabolic intermediates. Collectively, our data demonstrate that inhaled CO may be beneficial in preventing cerebral injury resulting from DHCA and offer important therapeutic options in newborns undergoing DHCA for open heart surgery.

Concepts: Brain, Mammal, Ischemia, Reperfusion injury, Therapeutic hypothermia, Cardiothoracic surgery, Cardiac surgery, Postperfusion syndrome

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166

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using (1)H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes.Journal of Cerebral Blood Flow & Metabolism advance online publication, 10 April 2013; doi:10.1038/jcbfm.2013.52.

Concepts: Myocardial infarction, Stroke, Traumatic brain injury, Temperature, Neurology, Ischemia, Infarction, Embolism

164

The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.Journal of Cerebral Blood Flow & Metabolism advance online publication, 25 September 2013; doi:10.1038/jcbfm.2013.173.

Concepts: Blood, Blood vessel, Stroke, Traumatic brain injury, Ischemia, Reperfusion injury, Subarachnoid hemorrhage, Hypoxia

143

Acute kidney injury (AKI) complicates recovery from cardiac surgery in up to 30 % of patients, injures and impairs the function of the brain, lungs, and gut, and places patients at a 5-fold increased risk of death during hospitalization. Renal ischemia, reperfusion, inflammation, hemolysis, oxidative stress, cholesterol emboli, and toxins contribute to the development and progression of AKI. Preventive strategies are limited, but current evidence supports maintenance of renal perfusion and intravascular volume while avoiding venous congestion, administration of balanced salt as opposed to high-chloride intravenous fluids, and the avoidance or limitation of cardiopulmonary bypass exposure. AKI that requires renal replacement therapy occurs in 2-5 % of patients following cardiac surgery and is associated with 50 % mortality. For those who recover from renal replacement therapy or even mild AKI, progression to chronic kidney disease in the ensuing months and years is more likely than for those who do not develop AKI. Cardiac surgery continues to be a popular clinical model to evaluate novel therapeutics, off-label use of existing medications, and nonpharmacologic treatments for AKI, since cardiac surgery is fairly common, typically elective, provides a relatively standardized insult, and patients remain hospitalized and monitored following surgery. More efficient and time-sensitive methods to diagnose AKI are imperative to reduce this negative outcome. The discovery and validation of renal damage biomarkers should in time supplant creatinine-based criteria for the clinical diagnosis of AKI.

Concepts: Renal failure, Chronic kidney disease, Nephrology, Medicine, Blood, Hospital, Blood vessel, Ischemia

113

Vitamin D has been suggested to have a role in various neurovascular diseases, but the data regarding headache is inconclusive. Our aim was to investigate the associations between serum 25-hydroxyvitamin D [25(OH)D], a marker for vitamin D status, and risk of frequent headache. The study population consisted of 2601 men from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) from eastern Finland, aged 42-60 years in 1984-1989. The cross-sectional associations with prevalence of self-reported frequent headache (defined as weekly or daily headaches) were estimated with multivariable-adjusted odds ratios. The average serum 25(OH) concentration was 43.4 nmol/L (SD 18.9, min-max 7.8-136.1 nmol/L). A total of 250 men (9.6%) reported frequent headache. The average serum 25(OH)D concentration among those with frequent headache was 38.3 nmol/L (SD 18.8) and 43.9 nmol/L (SD 18.9) among those without frequent headache, after adjustment for age and year and month of blood draw (P for difference <0.001). After multivariable adjustments, those in the lowest vs. the highest serum 25(OH)D quartile had 113% (95% CI 42, 218%; P for trend <0.001) higher odds for frequent headache. In conclusion, low serum 25(OH)D concentration was associated with markedly higher risk of frequent headache in men.

Concepts: Vitamin D, Epidemiology, Disease, Hypertension, Medical statistics, Ischemia, Headache, Ischaemic heart disease