Role of mineralocorticoid receptors in arterial stiffness in human aging

Arterial stiffness, an independent predictor of cardiovascular disease, is increased in aging, but the underlying mechanisms are not completely understood. Mineralocorticoid receptors (MR) may contribute to oxidative stress and arterial stiffness in healthy older adults. To test the hypothesis that short-term MR blockade may reduce oxidative stress and improve arterial stiffness, we conducted a randomized, double blind, crossover study using the selective MR blocker Eplerenone or placebo in 23 older adults (age, 64 ± 1 years; mean ± SE) free from overt cardiovascular and other clinical disease (e.g, diabetes, renal and liver disease). In response to MR blockade, brachial and carotid blood pressure decreased (P ≤ 0.01). However, MR blockade had no effect on oxidative stress (oxidized LDL, 61.2 ± 6.8 vs. 62.4 ± 7.4 U/L, P = 0.9; placebo vs. Eplerenone) and arterial stiffness (aortic pulse wave velocity (PWV), 9.17 ± 1.19 vs. 8.92 ± 1.19 m/s, P = 0.5; leg PWV, 13.45 ± 0.45 vs. 12.81 ± 0.47 m/s, P = 0.3; arm PWV, 11.43 ± 0.62 vs. 11.73 ± 0.68 m/s, P = 0.7; carotid artery compliance, 0.150 ± 0.013 vs. 0.149 ± 0.014 mm²/mm Hg, P = 0.8; distensibility, 23.1 ± 1.8 vs. 23.3 ± 1.7 10^− 3/kPa, P = 0.8; β stiffness index, 3.5 ± 0.3 vs. 3.6 ± 0.3, P = 0.6; and augmentation index, 16.0 ± 2.2 vs. 15.6 ± 2.8%, P = 0.8). These results provide the first evidence that MR do not appear to contribute to oxidative stress in human aging and that short-term MR blockade does not result in reduced oxidative stress and improved arterial stiffness.     

Delayed diagnosis, due to the associated radiological abnormalities, of spontaneous intracranial hypotension caused by cerebrospinal fluid leakage at C1-2

Spontaneous intracranial hypotension (SIH) is an uncommon clinical entity that is often diagnosed after a delay, or it is misdiagnosed due to the variety of clinical presentations and the associated radiological findings. We present here a case of SIH associated with chronic subdural haematoma (SDH) and subarachnoid haemorrhage. Following the diagnosis of the SIH, the patient underwent injection of an epidural blood patch for the SIH and burr hole trephination was done for treating the chronic subdural haematoma.     

Impaired sympathetic neural recruitment during exercise pressor reflex activation in women with post-traumatic stress disorder

Muscle sympathetic nerve activity (MSNA) increases during isometric exercise via increased firing of low-threshold action potentials (AP), recruitment of larger, higher-threshold APs, and synaptic delay modifications. Recent work found that women with post-traumatic stress disorder (PTSD) demonstrate exaggerated early-onset MSNA responses to exercise; however, it is unclear how PTSD affects AP recruitment patterns during fatiguing exercise. We hypothesized that women with PTSD (n?=?11, 43 [11] [SD] years) would exhibit exaggerated sympathetic neural recruitment compared to women without PTSD (controls; n?=?13, 40 [8] years). MSNA and AP discharge patterns (via microneurography and a continuous wavelet transform) were measured during 1 min of baseline, isometric handgrip exercise (IHG) to fatigue, 2 min of post-exercise circulatory occlusion (PECO), and 3 min of recovery. Women with PTSD were unable to increase AP content per burst compared to controls throughout IHG and PECO (main effect of group: P?=?0.026). Furthermore, relative to controls, women with PTSD recruited fewer AP clusters per burst during the first (controls: ?1.3 [1.2] vs. PTSD: ??0.2 [0.8]; P?=?0.016) and second minute (controls: ?1.2 [1.1] vs. PTSD: ??0.1 [0.8]; P?=?0.022) of PECO, and fewer subpopulations of larger, previously silent axons during the first (controls: ?5 [4] vs. PTSD: ?1 [2]; P?=?0.020) and second minute (controls: ?4 [2] vs. PTSD: ?1 [2]; P?=?0.021) of PECO. Conversely, PTSD did not modify the AP cluster size–latency relationship during baseline, the end of IHG, or PECO (all P?=?0.658–0.745). Collectively, these data indicate that women with PTSD demonstrate inherent impairments in the fundamental neural coding patterns elicited by the sympathetic nervous system during IHG and exercise pressor reflex activation.

     

Posture-related changes in sympathetic baroreflex sensitivity during normal pregnancy

Clinical Autonomic Research - Normal pregnancy is associated with vast adjustments in cardiovascular autonomic control. Sympathetic baroreflex sensitivity has been reported to be attenuated during...