Cardiometabolic risk factors predict cerebrovascular health in older adults: results from the Brain in Motion study.

Aging and physical inactivity are associated with an increased risk of developing metabolic syndrome (MetS). With the rising prevalence of MetS, it is important to determine the extent to which it affects cerebrovascular health. The primary purpose of this report is to examine the impact of MetS on cerebrovascular health (resting cerebral blood flow (CBF) peak velocity (V¯P), cerebrovascular conductance (CVC), and CBF responses to hypercapnia) in healthy older adults with normal cognition.

A nephrology guide to reading and using systematic reviews of observational studies.

Systematic reviews are an ideal way of summarizing evidence from primary studies. While systematic reviews of randomized trials are broadly used to summarize benefits and harms of interventions, systematic reviews of observational studies are useful to summarize data on prevalence of risk factors in a population, distribution of outcomes or associations of different risk factors with outcomes. Also, systematic reviews can be useful to clarify potential reasons for conflicting data found in primary studies and explore sources of heterogeneity (variation in primary study data) to better understand epidemiological data and generate hypotheses for candidate interventions to improve outcomes.

Human intermittent hypoxia-induced respiratory plasticity is not caused by inflammation.

Ventilatory instability, reflected by enhanced acute hypoxic (AHVR) and hypercapnic (AHCVR) ventilatory responses is a fundamental component of obstructive sleep apnoea (OSA) pathogenesis. Intermittent hypoxia-induced inflammation is postulated to promote AHVR enhancement in OSA, although the role of inflammation in intermittent hypoxia-induced respiratory changes in humans has not been examined. Thus, this study assessed the role of inflammation in intermittent hypoxia-induced respiratory plasticity in healthy humans.

Studying cerebral hemodynamics and metabolism using simultaneous near-infrared spectroscopy and transcranial Doppler ultrasound: a hyperventilation and caffeine study.

Caffeine is one of the most widely consumed psycho-stimulants in the world, yet little is known about its effects on brain oxygenation and metabolism. Using a double-blind, placebo-controlled, randomized cross-over study design, we combined transcranial Doppler ultrasound (TCD) and near-infrared spectroscopy (NIRS) to study caffeine's effect on middle cerebral artery peak blood flow velocity (Vp), brain tissue oxygenation (StO2), total hemoglobin (tHb), and cerebral oxygen metabolism (CMRO2) in five subjects. Hyperventilation-induced hypocapnia served as a control to verify the sensitivity of our measurements.

Serum uric acid level, blood pressure, and vascular angiotensin II responsiveness in healthy men and women.

Uric acid is associated with hypertension and increased renin-angiotensin system activity, although this relationship diminishes after chronic exposure to high levels. Uric acid is more strongly associated with poor outcomes in women compared to men, although whether this is due to a sex-specific uric acid-mediated pathophysiology or reflects sex differences in baseline uric acid levels remains unknown. We examined the association between uric acid and vascular measures at baseline and in response to angiotensin-II challenge in young healthy humans.

Risk of death following kidney allograft failure: a systematic review and meta-analysis of cohort studies.

Background: People with kidney allograft failure represent an increasing fraction of all those starting dialysis therapy. We sought to summarize prognosis following kidney allograft failure and identify potentially beneficial interventions or modifiable risk factors.

Methods: We searched MEDLINE and EMBASE (inception to 1 October 2013) and article reference lists without language restriction and selected cohort studies of all-cause mortality and fatal infection-related and cardiovascular events in people starting dialysis following kidney allograft failure.

IgA nephropathy with early kidney disease is associated with increased arterial stiffness and renin-angiotensin system activity.

Background: IgA nephropathy is associated with increased cardiovascular risk, though whether this is due to loss of kidney function or proteinuria is unclear.

Methods: For this study 10 normotensive IgA nephropathy subjects with early kidney disease (41±5 yrs, glomerular filtration rate (GFR) 87±9 ml/min, proteinuria 720±300 mg/d) and 10 gender- and blood pressure-matched healthy controls (36±1 yrs, estimated GFR 102±5 ml/min, proteinuria 70±6 mg/d) were studied in high-salt balance. Blood pressure and arterial stiffness, expressed as pulse wave velocity and aortic augmentation index, were measured at baseline and in response to 60 min of angiotensin II (AngII) infusion.