Glutamergic Action on Alpha-Melanocyte-Stimulating Hormone Release from the Rat Hypothalamus

Release of α-melanocyte-stimulating hormone (α-MSH) synthesized in the hypothalamus is regulated by monoaminergic neuronal systems. An endogenous dopaminergic system inhibits α-MSH release (1, 2) whilst serotoninergic systems exert a biphasic effect on peptide release (3). The toxic effects of neonatal peripheral administration of monosodium glutamate on hypothalamic neurons containing proopiomelanocortin- (POMC-) derived peptides (4, 5) suggest additionally the presence of glutamate receptors on or indirectly influencing the POMC neuron. By comparison of the effect of the excitatory amino-acid agonists N-methyl-D-aspartate (NMDA), quisqualate and kainate on the release of α-MSH from superfused slices of rat hypothalamus, we have demonstrated a stimulatory glutamergic action on α-MSH release mediated through NMDA-type receptors.     

Regression of Atherosclerosis

Atherosclerotic cardiovascular disease (CVD) is a complex disorder that leads to premature death and hospitalization. Several drugs have been, or are currently being tested for their ability to reduce cardiovascular mortality and/or promote regression of atherosclerotic lesions. In addition to "hard end point" clinical trials in which total and cardiovascular mortality as well as risk of incident myocardial infarction are considered as outcomes, trials with surrogate end points using imaging biomarkers can rapidly assess the efficacy of new cardiovascular drugs. Low-density lipoprotein-based therapies with statins have been shown to promote atherosclerosis regression, and several other drugs targeting high-density lipoproteins or inflammation/oxidation are currently being tested in both outcomes and imaging trials in which atherosclerosis regression is anticipated. In this review, we focus on the latest progress in CVD and highlight novel drugs that tackle atherosclerosis as well as the currently used and upcoming imaging techniques to optimally measure atherosclerosis progression.     

The effect of a 6-month intradialytic exercise program on hemodialysis adequacy and body composition: a randomized controlled trial

Background/aim

End-stage kidney disease (ESKD) is strongly associated with factors that aggravate the physical activity level and body composition status of hemodialysis patients (HD). Even though exercise in HD patients have shown remarkable benefits on hemodialysis adequacy, it is yet inconclusive if exercise can positively affect body composition parameters or if dialysis adequacy may affect body composition status. This study aimed to investigate the effect of a 6-month intradialytic exercise training program on dialysis adequacy indices and body composition parameters in HD patients.

Study design

A total of 24 HD patients were randomly assigned into two equally sized groups. The exercise group (EX group) participated in a 6-month intradialytic moderate-intensity aerobic exercise training program at the beginning of the HD sessions, three times a week for 60 min, and maintained a Borg’s Rating of Perceived Exertion score between 13 and 14. The Control group (C group) remained untrained. At baseline, during, and at the end of the 6-month study, we assessed single-pool Kt/V, urea reduction ratio (URR), and body composition parameters, such as extracellular water (ECW)/ intracellular water (ICW) ratio, body mass index (BMI) and lean tissue mass (LTM). In all patients, the 6-min-walking test (6MWT) was performed as a marker of physical performance.

Results

A significant increase of both Kt/V (increase by 19%, p?=?0.01), and URR (increase by 7%, p?=?0.03) values has been observed in the EX group after the 6-month training program. Similarly, a statistically significant increase in 6MWT distance (from 442?±?67 m to 481?±?68 m, p?=?0.02) in the EX group has also been found, compared to the C group (from 393?±?59 m to 427?±?81 m, p?=?0.06). Neither EX nor C group has shown significant changes in body composition parameters. After training, linear regression analysis revealed a strong positive correlation between Kt/V and 6MWT changes (r?=?0.74, p?=?0.04) in the EX group.

Conclusions

Six months of intradialytic aerobic exercise might increase dialysis adequacy, by increasing Kt/V and URR, and physical performance, regardless of changes in body composition indices.