The Effect of Nitric Oxide on Remote Ischemic Preconditioning in Renal Ischemia Reperfusion Injury in Rats

Multi-omics analysis of renal vein serum with Ischemia-Reperfusion injury

BACKGROUND

Acute kidney injury (AKI) is frequently caused by renal ischemia-reperfusion injury (IRI). Identifying potential renal IRI disease biomarkers would be useful for evaluating AKI severity.

OBJECTIVE

We used proteomics and metabolomics to investigate the differences in renal venous blood between ischemic and healthy kidneys in an animal model by identifying differentially expressed proteins (DEPs) and differentially expressed protein metabolites (DEMs).

METHODS

Nine pairs of renal venous blood samples were collected before and at 20, 40, and 60 min post ischemia. The ischemia time of Group A, B and C was 20,40 and 60 min. The proteome and metabolome of renal venous blood were evaluated to establish the differences between renal venous blood before and after ischemia.

RESULTS

We identified 79 common DEPs in all samples of Group A, 80 in Group B, and 131 in Group C. Further common DEPs among all three groups were Tyrosineprotein kinase, GPR15LG, KAZALD1, ADH1B. We also identified 81, 64, and 83 common DEMs in each group respectively, in which 30 DEMs were further common to all groups. Bioinformatic analysis of the DEPs and DEMs was conducted.

CONCLUSION

This study demonstrated that different pathological processes occur during short- and long-term renal IRI. Tyrosine protein kinase, GPR15LG, Kazal-type serine peptidase inhibitor domain 1, and all-trans-retinol dehydrogenase are potential biomarkers of renal IRI.

Nontopical Nitrates in Flap Perfusion and Delay Phenomenon

Background

Topical nitrates have demonstrated efficacy in improving flap perfusion. However, evidence for nontopical nitrates in modulation of flap perfusion dynamics has yet to be consolidated. Here, we review evidence regarding the use of intravascular, sublingual, and oral nitrates in modulating flap perfusion.

Methods

We performed a review of the literature for evidence linking nontopical nitrates and flap perfusion, and included clinical studies, animal studies, and in vitro studies.

Results

Evidence suggests that intravascular, sublingual, and oral nitrates exert vasodilatory properties, which may be harnessed for identification of perforators and improved flap perfusion. We also found evidence suggesting nitrates may facilitate ischemic preconditioning while reducing ischemia-reperfusion injury.

Conclusions

Nitrates delivered intravascularly, sublingually, or orally may increase flap perfusion and serve as a method for ischemic preconditioning, particularly in the intraoperative setting.

Influence of Remote Ischemic Conditioning and Nitrogen Monoxide on Angiogenesis and Microcirculation in a Mouse Ear Burn Model

INTRODUCTION

Remote ischemic conditioning (RIC) has been shown to improve tissue resilience against ischemia. The aim of this study was to investigate the influence of RIC and its key factor, nitrogen monoxide (NO), on angiogenesis in a burn wound.

MATERIALS AND METHODS

A unilateral burn injury on the ear of hairless mice (n = 48) was generated via a hot air jet in a contact-free manner. In four randomized groups, including the control (NoRIC group), RIC alone (RIConly group), RIC plus NO donor (ISDN group), and RIC plus NO synthase inhibitor (L-NAME group), the impact on angiogenesis, vessel diameter, blood flow, edema formation, and leukocyte-endothelial-cell interaction was evaluated over a 12-d period using intravital fluorescence microscopy.

RESULTS

Tissue perfusion was significantly improved by RIC (Day 3: ISDN group showed 182% and RIConly group showed 200% of baseline [BL], P < 0.001), while angiogenesis was not improved by RIC (nonperfused area on Day 12: mean 52% of BL in all groups, P >0.05). The application of ISDN did not further enhance the positive effect of RIC, whereas the application of L-NAME neutralized the effect of RIC. The most pronounced edema formation was observed in the RIConly group (mean 145% of BL, P ≤0.001), while the NoRIC group showed the least edema formation (Day 12: 117% of BL).

CONCLUSIONS

RIC led to increased tissue perfusion, which did not result in improved angiogenesis, which may have been due to increased edema formation after RIC performance. The results of the present study do not support the establishment of a causal therapy strategy for burn wounds, including RIC.

Pharmacological Inhibition of Class III Alcohol Dehydrogenase 5: Turning Remote Ischemic Conditioning Effective in a Diabetic Stroke Model

The restoration of cerebral blood flow (CBF) to achieve brain tissue oxygenation (PbtO₂) is the primary treatment for ischemic stroke, a significant cause of adult mortality and disability worldwide. Nitric oxide (NO) and its bioactive s-nitrosylated (SNO) reservoirs, such as s-nitrosoglutathione (GSNO), induce hypoxic vasodilation to enhance CBF during ischemia. The endogenous pool of SNOs/GSNO is enhanced via the activation of endothelial NO synthase (eNOS/NOS3) and by the suppression of class III alcohol dehydrogenase 5 (ADH5), also known as GSNO reductase (GSNOR). Remote ischemic conditioning (RIC), which augments NOS3 activity and SNO, is an emerging therapy in acute stroke. However, RIC has so far shown neutral effects in stroke clinical trials. As the majority of stroke patients are presented with endothelial dysfunctions and comorbidities, we tested the hypothesis that NOS3 dysfunction and diabetes will abolish the protective effects of RIC therapy in stroke, and the prior inhibition of GSNOR will turn RIC protective. Our data demonstrate that RIC during thrombotic stroke failed to enhance the CBF and the benefits of thrombolysis in NOS3 mutant (NOS3^+/−) mice, a genetic model of NOS3 dysfunction. Interestingly, thrombotic stroke in diabetic mice enhanced the activity of GSNOR as early as 3 h post-stroke without decreasing the plasma nitrite (NO₂⁻). In thrombotic stroke, neither a pharmacological inhibitor of GSNOR (GRI) nor RIC therapy alone was protective in diabetic mice. However, prior treatment with GRI followed by RIC enhanced the CBF and improved recovery. In a reperfused stroke model, the GRI–RIC combination therapy in diabetic mice augmented PbtO₂, a translatory signature of successful microvascular reflow. In addition, RIC therapy unexpectedly increased the inflammatory markers at 6 h post-stroke in diabetic stroke that were downregulated in combination with GRI while improving the outcomes. Thus, we conclude that preexisting NOS3 dysfunctions due to comorbidities may neutralize the benefits of RIC in stroke, which can be turned protective in combination with GRI. Our findings may support the future clinical trial of RIC in comorbid stroke. Further studies are warranted to test and develop SNO reservoirs as the blood-associated biomarker to monitor the response and efficacy of RIC therapy in stroke.

Efficacy of low extra-abdominal aortic block in cesarean section for placenta accreta spectrum disorders and its effect on the expression of MDA and SOD

OBJECTIVES

Placenta accreta spectrum disorders (PAS) refers to a group of abnormalities in placental adhesion and invasion, which may lead to serious complications such as intractable postpartum hemorrhage. The use of low-level extra-abdominal aortic temporary block during cesarean section may reduce intraoperative bleeding in patients with PAS, but it may also cause ischemia-reperfusion injury. In this study, we intend to investigate the efficacy of low extra-abdominal aortic block in cesarean section for placental implantation disease and its effect on malondialdehyde (MDA) level and superoxide dismutase (SOD) activity, and analyze the severity of ischemia-reperfusion injury caused by them.

METHODS

Pregnant women with invasive placenta accreta spectrum disorders who delivered in the Department of Obstetrics and Gynecology of the Third Xiangya Hospital of Central South University from July 2017 to July 2021, were selected, and they were divided into 2 groups. Group A consisted of those who underwent low extra-abdominal aortic block during cesarean section (n=15) and group B consisted of those who did not undergo extra-abdominal aortic block (n=15). The intraoperative bleeding, blood transfusion, hysterectomy and complication rate, postoperative hospital stay and hospitalization expenses were compared between the 2 groups to analyze the efficacy of abdominal aortic block. The biochemical indexes related to ischemia-reperfusion, MDA content and total superoxide dismutase (T-SOD) activity, were measured at the corresponding time points in both groups. The time points of each test were: in group A, before the block of the low extra-abdominal aorta after delivery (A0), 0 h (A1, when the myometrium was started to be sutured), 0.5 h (A2), 2 h (A3), and 4 h (A4) after the open block; in group B, after delivery of the fetus (B0), 0 h (B1), 0.5 h (B2), 2 h (B3), and 4 h (B4) after the myometrium was started to be sutured. Total duration of abdominal aortic block in group A was also recorded. Both groups were observed for sings of edema, ischemia, necrosis and infection in the limbs after surgery. The severity of ischemia-reperfusion injury caused by abdominal aortic block were determined by detecting the relevant biochemical indexes at different moments of reperfusion.

RESULTS

The intraoperative bleeding and blood transfusion in group A were less than those in group B, and the difference was statistically significant (P<0.05). There was no significant difference in postoperative hospital stay and hospitalization expenses between the 2 groups (P>0.05). Surgical complications: in group A, the uterus was preserved in all cases, there was 1 bladder injury and 2 pelvic infections; while in group B, there was 1 hysterectomy, 3 bladder injuries, and 3 pelvic infections. Changes in T-SOD and MDA values: compared with A0 before block, the MDA level was significantly elevated in blood at time points A1, A2, and A3, while SOD activity was significantly decreased (P<0.05), and the 2 observed indexes basically returned to A1 level (ischemic period) at 4 h after open block (A4). There was no significant difference in the changes of T-SOD and MDA in group B (P>0.05). Comparison of T-SOD and MDA levels between group A and B: the difference of the 2 indexes was not statistically significant between A0 and B0 (P>0.05), MDA level was not statistically significant between A1 and B1, T-SOD activity at A1 was lower than B1, the difference was statistically significant, at the rest of the same time point, MDA level in group A were higher than that in group B, T-SOD activity in group A were lower than that in group B, the difference was statistically significant (P<0.05). No postoperative limb edema, ischemia, necrosis, or infection occurred in both groups.

CONCLUSIONS

Low-level extra-abdominal aortic block effectively reduces bleeding and transfusion during cesarean section for placenta accreta spectrum disorders, resulting in a transient MDA elevation and a decrease of SOD activity, which means causing transient ischemia-reperfusion injury without complications such as limb edema, ischemia, necrosis, and infection.

Pretreatment of Nicorandil Protects the Heart from Exhaustive Exercise-Induced Myocardial Injury in Rats

OBJECTIVE

Nicorandil has been widely used for the treatment of angina pectoris and myocardial infarction. The purpose of this study was to investigate whether nicorandil plays a protective role in exhaustive exercise (EE)-induced myocardial injury.

METHODS

Here, we applied the rat EE model and treated them with exercise preconditioning (EP, reported to protect the heart) or different doses of nicorandil gavage, respectively, to explore whether there are protective effects of single EP or nicorandil or a combination of both and the potential mechanism. Forty-nine male Sprague Dawley rats were randomly divided into control, EE, EP + EE, nicorandil (with low, middle, and high dose) + EE, and EP + nicorandil (middle dose) + EE. Blood samples and myocardial tissues were collected to analyze the myocardial injury-related index.

RESULTS

EE induced myocardial structural damage and altered the myocardial injury markers, which were partially reversed by pretreatment of nicorandil. In addition, oxidative stress and inflammation lead to the accumulation of reactive oxygen species (ROS) products and further damage to the myocardium, while pretreatment of nicorandil reduces the oxidative stress response and inflammation. Moreover, nicorandil suppressed the myocardial apoptosis induced by EE, as indicated by a decrease of Bax and caspase-3 expression and an increase of Bcl-2 expression. Finally, the pathway in which nicorandil plays a role may be involved in the endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) pathway. Pretreatment of nicorandil increased the protein level of myocardial eNOS and NO production.

CONCLUSION

Our result demonstrated that nicorandil has protective effects in EE-induced myocardial injury with dose-dependent effects. A combination of nicorandil and EP can further improve the protective effects. Taken together, nicorandil can be potentially used as an intervention method in EE-induced myocardial injury.

Nature's marvels endowed in gaseous molecules I: Carbon monoxide and its physiological and therapeutic roles

Nature has endowed gaseous molecules such as O2, CO2, CO, NO, H2S, and N2 with critical and diverse roles in sustaining life, from supplying energy needed to power life and building blocks for life's physical structure to mediating and coordinating cellular functions. In this article, we give a brief introduction of the complex functions of the various gaseous molecules in life and then focus on carbon monoxide as a specific example of an endogenously produced signaling molecule to highlight the importance of this class of molecules. The past twenty years have seen much progress in understanding CO's mechanism(s) of action and pharmacological effects as well as in developing delivery methods for easy administration. One remarkable trait of CO is its pleiotropic effects that have few parallels, except perhaps its sister gaseous signaling molecules such as nitric oxide and hydrogen sulfide. This review will delve into the sophistication of CO-mediated signaling as well as its validated pharmacological functions and possible therapeutic applications.

Oleuropein Improved Post Cerebral Stroke Cognitive Function by Promoting Histone Acetylation and Phosphorylation of cAMP Response Element-Binding Protein in MCAO Rats

Background:

Post-stroke cognitive impairment (PSCI) is commonest clinical disorder in which peripheral cholinergic activity is important. Oleuropein (OLP) is polyphenol is present in olive oil. Here we evaluated the effect of OLP in cognitive dysfunction rats in post cerebral stroke model.

Methods:

The post cerebral stroke cognitive dysfunction PSD rat model was created by occlusion of transient middle cerebral artery. The rats were divided into 6 groups named, Sham + Vehicle, Sham + OLP (50 mg/kg), PSD rats + Vehicle, PSD rats + OLP (20, 50 or 100 mg/kg). The spatial learning was assessed by Morris water maze (MWM). The expression of choline acetyltransferase (ChAT), acetylcholine (ACH), extent of histone acetylation and phosphorylation of cAMP response element-binding protein (CREB) were evaluated by Western blot assay and immunofluorescence staining.

Results:

Treatment of OLP at various doses showed higher number of spontaneous and rewarded alterations and lesser percentage bias compared to vehicle treated PSD rats. OLP resulted in decreased levels of ChAT and ACH, whereas the degree of histone acetylation and phosphorylation of CREB improved in dose dependent pattern.

Conclusion:

treatment of OLP improved PSCI via increasing the phosphorylation of CREB and histone acetylation, thus attenuating cholinergic activity.