Oxidative stress augments the secretion of atrial natriuretic peptide in isolated rat atria

Circulating corin concentration is associated with risk of mortality and acute kidney injury in critically ill patients

Elevated serum corin concentrations in patients with cardiac diseases have been associated with adverse cardiovascular events and progressive renal dysfunction. This study aimed to determine the role of serum corin levels in predicting the incidence of acute kidney injury (AKI) and mortality in critically ill patients admitted to intensive care units (ICUs). We screened 323 patients admitted to the ICU in our institution from May 2018 through December 2019. After excluding patients receiving renal replacement therapy, 288 subjects were enrolled. Cases were divided equally into high (n = 144) and low (n = 144) corin groups according to median serum corin levels, using 910 pg/mL as the cut-off point. Patient characteristics and comorbidities were collected from medical records. The primary outcome was AKI within 48 h after ICU admission, while the secondary outcome was all-cause of mortality within 1 year. Compared with the low corin group, patients in the high corin group had higher prevalence rates of diabetes, cirrhosis, and nephrotoxic agent exposure; higher Sequential Organ Failure Assessment scores, white blood cell counts, proteinuria, and serum N-terminal pro-brain natriuretic peptide levels; but had lower initial estimated glomerular filtration rates. Furthermore, elevated serum corin was associated with higher risks of AKI within 48h of ICU admission (43.1% vs. 18.1%, p < 0.001) and all-cause mortality within one year (63.9% vs. 50.0%, p = 0.024). High corin level showed strongly positive results as an independent predictor of AKI (OR 2.15, 95% CI 1.11-4.19, p = 0.024) but not for the all-cause mortality after adjusting for confounding factors in multivariate analyses. Elevated circulating corin predicted AKI in critically ill patients, but did not predict all-cause mortality within 1 year. As a key enzyme in renin-angiotensin-aldosterone system, corin expression may be regulated through a feedback loop following natriuretic peptide resistance and desensitization of natriuretic peptide receptors in different critically ill status.

Ameliorating effect of rutin against diclofenac-induced cardiac injury in rats with underlying function of FABP3, MYL3, and ANP

Diclofenac is a widely prescribed anti-inflammatory drug having cardiovascular complications as one of the main liabilities that restrict its therapeutic use. We aimed to investigate for any role of rutin against diclofenac-induced cardiac injury with underlying mechanisms as there is no such precedent to date. The effect of rutin (10 and 20 mg/kg) was evaluated upon concomitant oral administration for fifteen days with diclofenac (10 mg/kg). Rutin significantly attenuated diclofenac-induced alterations in the serum cardiac markers (LDH, CK-MB, and SGOT), serum cytokine levels (TNF-α and IL-6), and oxidative stress markers (MDA and GSH) in the cardiac tissue. Histopathological examination and Scanning Electron Microscopy (SEM) findings displayed a marked effect of rutin to prevent diclofenac-mediated cardiac injury. Altered protein expression of myocardial injury markers (cTnT, FABP3, and ANP) and apoptotic markers (Bcl-2 and Caspase-3) in the cardiac tissue upon diclofenac treatment was considerably shielded by rutin treatment. MYL3 was unaffected due to diclofenac or rutin treatment. Rutin also significantly improved diclofenac-induced gastrointestinal and hepatic alterations based on the observed ameliorative effects in key mediators, oxidative stress markers, histopathology examination, and SEM findings. Overall results suggest that rutin can protect the diclofenac-induced cardiac injury by lowering oxidative stress, inhibiting inflammation, and reducing apoptosis. Further research work directs toward the development of phytotherapeutics for cardioprotection.

Therapeutic role of atrial natriuretic peptide in early treatment of traumatic hemorrhagic shock

The biological effect of atrial natriuretic peptide (ANP) in traumatic hemorrhagic shock (THS) is unknown. This study was to evaluate whether ANP therapy can show organ protection in THS. Thirty male Sprague-Dawley rats were divided into three groups: ANP group, sham group, and control group. Pressure-controlled THS was induced in rats in ANP group and control group. ANP at a rate of 0.025 μg/kg/min was infused in ANP group during near-80 min of shock. After that, animals were resuscitated for 60 min and observed until 24 h. Hemodynamic parameters during shock and resuscitation were measured. Serum levels of ANP and lactate dehydrogenase, tissue oxidative stress and inflammatory factors, as well as liver and kidney function were determined. Tissue apoptosis was also assessed. There was no statistically significant difference between ANP group and control group in arterial pressure throughout the 150 min monitoring period. Blood urea nitrogen at 90 min and 24 h in ANP group was significantly lower than control group. Alanine transaminase and aspartate aminotransferase activity at 90 min in control group were significantly higher than that in sham group. However, hepatic enzyme activity at 90 min in ANP group was not significantly different compared with sham or control group. After 24 h, myocardial expression of caspase 3 protein in ANP group was significantly reduced compared with control group. Jejunal and hepatic Malondialdehyde was increased following ANP treatment. ANP therapy during early THS has no significant adverse effect on hemodynamics but can exert oxidative stress and certain protective effect on multiple organs. Our study may shed light on the novel therapy of THS with regard to organ protection. The mechanisms underlying the organ protection require further study.

Effect of geumgoeshingi-whan pharmacopuncture on the blood pressure in spontaneously hypertensive rats

OBJECTIVE

The aim of this experiment was to investigate the effect and the mechanism of Geumgoeshingi-whan (GGSGW) Pharmacopuncture at the acupoint GV 4 on the blood pressure in spontaneously hypertensive rats (SHR).

METHODS

SHR were injected with normal saline solution (Control-SHR group)or GGSGW Pharmacopuncture (GGSGW-SHR group) at the acupoint GV 4. The systolic arterial blood pressure and renal parameters were measured for two weeks.

RESULTS

The systolic arterial blood pressure was decreased significantly after GGSGW Pharmacopuncture at the acupoint GV 4 in SHR, followed by a significant rise in creatine clearance. The plasma levels of aldosterone were decreased significantly after GGSGW Pharmacopunctureas were the plasma levels of atrial natriuretic peptide (ANP).

CONCLUSION

These results suggest that the blood pressure was decreased significantly after GGSGW Pharmacopuncture at the acupoint GV 4 in SHR and that the depressor response of the blood pressure was related to decreases in the plasma levels of aldosterone and ANP.

Suppression of high pacing-induced ANP secretion by antioxidants in isolated rat atria

Reactive oxygen species (ROS) are formed as a natural by-product of the normal metabolism of oxygen and have important roles in cell signaling. The aim of this study was to investigate direct effects of ROS on atrial hemodynamics and ANP secretion in isolated perfused beating rat atria with antioxidants. When atria were paced at 1.2 Hz, N-acetyl cystein (antioxidant, NAC), α-lipoic acid (antioxidant), tempol (superoxide dismutase mimic), and apocynin (NADPH oxidase inhibitor; NOX inhibitor) did not affect ANP secretion and atrial contractility. When pacing frequency was increased from 1.2 Hz to 4 Hz, the ANP secretion increased and atrial contractility decreased. H(2)O(2) level was increased in perfusate obtained from atria stimulated by high pacing frequency. NAC, α-lipoic acid and tempol attenuated high pacing frequency-induced ANP secretion but apocynin did not. In contrast, pyrogallol (a superoxide generator) augmented high pacing frequency-induced ANP secretion. NOX-4 protein was increased by high pacing stimulation and in diabetic rat atria. In diabetic rat atria, high pacing frequency caused an increased ANP secretion and a decreased atrial contractility, that were markedly attenuated as compared to control rats. NAC and apocynin reduced high pacing frequency-induced ANP secretion in diabetic rat atria. These results suggest that intracellular ROS formation partly through an increasing NOX activity in response to high pacing frequency is associated with an increased ANP secretion in rat atria.