Prevention Of Ischemia-reperfusion Injury Research Articles

The Use of CRISPR-Cas9 Genetic Technology in Cardiovascular Disease: A Comprehensive Review of Current Progress and Future Prospective.

Over the last century, there have been major landmark developments in the field of medicine, enabling us to control and cure various diseases on a larger scale. A few of these include the discovery of antibiotics, the development of vaccines, and the origin of organ and tissue transplants. The continued quest for innovation in microbiology and medicine has helped humankind save millions of lives and decrease morbidity at the global level.Genetic medicine has grown significantly in the last two decades and appears to be the next frontier of curative therapies for chronic diseases. One important landmark in genetic medicine is the development of CRISPR (clustered, regularly interspaced short palindromic repeats) technology. In this article, we describe the basic structure and function of the CRISPR-Cas9 system, which, simply put, consists of an RNA part and a protein. It works as a molecular scissor that can perform targeted cuts followed by repairs in and around the genes of interest to attain favorable translational outcomes. We focused on summarizing recent studies using CRISPR-Cas9 technology in diagnosing and treating cardiovascular disease. These studies are primarily experimental and limited to animal models. However, their results are promising enough to anticipate that this technology will undoubtedly be available in clinical medicine in the coming years. CRISPR-Cas9-mediated gene editing has been used to study and potentially treat congenital heart disease, hyperlipidemias, arrhythmogenic cardiomyopathies, and the prevention of ischemia-reperfusioninjury. Despite the current progress, we recognize the several challenges this technology faces, including funding for research, improving precision and reproducible results for human subjects, and establishing protocols for ethical compliance so that it is acceptable to the scientific community and the general public.

Protective role of kallistatin in oxygen-glucose deprivation and reoxygenation in human umbilical vein endothelial cells.

Ischemia-reperfusion (IR) injury is implicated in various clinical diseases. Kallistatin attenuates oxidative stress, and its deficiency has been associated with poor neurological outcomes after cardiac arrest. The present study investigated the antioxidant mechanism through which kallistatin prevents IR injury. Human umbilical vein endothelial cells (HUVECs) were transfected with small interfering RNA (siRNA) targeting the human kallistatin gene (SERPINA4). Following SERPINA4 knockdown, the level of kallistatin expression was measured. To induce IR injury, HUVECs were exposed to 24 h of oxygen-glucose deprivation and reoxygenation (OGD/R). To evaluate the effect of SERPINA4 knockdown on OGD/R, cell viability and the concentration of kallistatin, endothelial nitric oxide synthase (eNOS) and total NO were measured. SERPINA4 siRNA transfection suppressed the expression of kallistatin in HUVECs. Exposure to OGD/R reduced cell viability, and this effect was more pronounced in SERPINA4 knockdown cells compared with controls. SERPINA4 knockdown significantly reduced kallistatin concentration regardless of OGD/R, with a more pronounced effect observed without OGD/R. Furthermore, SERPINA4 knockdown significantly decreased eNOS concentrations induced by OGD/R (P<0.01) but did not significantly affect the change in total NO concentration (P=0.728). The knockdown of SERPINA4 resulted in increased vulnerability of HUVECs to OGD/R and significantly affected the change in eNOS level induced by OGD/R. These findings suggest that the protective effect of kallistatin against IR injury may contribute to its eNOS-promoting effect.

Si-based agent alleviated small bowel ischemia–reperfusion injury through antioxidant effects

The progression of small bowel ischemia–reperfusion (IR) injury causes cells in the intestinal tract to undergo necrosis, necessitating surgical resection, which may result in loss of intestinal function. Therefore, developing therapeutic agents that can prevent IR injury at early stages and suppress its progression is imperative. As IR injury may be closely related to oxidative stress, antioxidants can be effective therapeutic agents. Our silicon (Si)-based agent, an antioxidant, generated a large amount of hydrogen in the intestinal tract for a prolonged period after oral administration. As it has been effective for ulcerative colitis, renal failure, and IR injury during skin flap transplantation, it could be effective for small intestinal IR injury. Herein, we investigated the efficacy of an Si-based agent in a mouse model of small intestinal IR injury. The Si-based agent suppressed the apoptosis of small intestinal epithelial cells by reducing the oxidative stress induced by IR injury. In addition, the thickness of the mucosal layer in the small intestine of the Si-based agent-administered group was significantly higher than that in the untreated group, revealing that Si-based agent is effective against small intestinal IR injuries. In the future, Si-based agents may improve the success rate of small intestine transplantation.

Abstract 27: A Novel Adjuvant Strategy After Endovascular Therapy: Arterial Glyceryl Trinitrate in Acute Ischemic Stroke for Neuroprotection (AGAIN)

Introduction: Although mechanical thrombectomy (MT) demonstrates robust clinical efficacy in acute ischemic stroke (AIS), not all stroke patients benefit from successful reperfusion. The protective effect of NO donors has been shown to prevent ischemia-reperfusion injury through reduction of reactive oxygen species formation in cardiovascular studies. Glyceryl Trinitrate (GTN), a Food and Drug Administration-approved vasodilator, is one of the widely used exogenous NO donors used in the clinic and has been trialed for neuroprotection in AIS without successful clinical translation. The recent advances in MT for AIS have paved the way for promising new opportunities to supplementary neuroprotective therapies to patients after reperfusion. This study evaluated the safety, feasibility, and preliminary efficacy of intra-arterial administration of GTN after MT for neuroprotection. Methods: This is a prospective randomized controlled study (ID: ChiCTR2100045254). Eligible patients were randomized to receive 800μg GTN or same volume of normal saline through the catheter after recanalization. The primary outcome was symptomatic intracranial hemorrhage (sICH), while secondary outcomes included mortality, functional outcome, infarction volume, complications, and blood nitrate index (NOx). Results: A total of 40 patients were enrolled and randomized with no participants being lost to follow-up. There was no significant difference in the proportion of sICH between GTN and control groups. No significant difference was observed in mortality or rates of neurological deterioration and other complications. Favorable trends for both functional independence (mRS 0-2, 75.0% vs. 65.0%) at 90 days and reduction in final infarct volume (33.2 vs. 38.9 ml) have been observed in GTN group, although they did not reach the significant levels. Moreover, the concentration of blood NO X was increased (p&lt;0.05) at 2 hours after GTN administration (26.2 vs 18.0 μmol/l). Conclusion: The AGAIN study suggests intra-arterial administration of GTN post MT is safe and feasible in AIS patient. The discernible positive trends may be due to the raised NO X levels, which potentially highlight the mechanistic reinforcement for these observed benefits.

ТЕПЛОВАЯ ИШЕМИЯ ПОЧКИ: КОНЦЕПЦИЯ ПРЕОДОЛЕНИЯ ИШЕМИЧЕСКОГО ПОВРЕЖДЕНИЯ ПОЧКИ ПРИ ОПЕРАЦИЯХ НА ПОЧЕЧНОМ СЕГМЕНТЕ АОРТЫ

The article presents some aspects of acute kidney injury (AKI) during operations on the renal segment of the aorta and renal arteries. The terminology and individual links in the pathogenesis of ischemic-reperfusion injuries are considered. A brief review of methods for preventing ischemia-reperfusion injury during operations on the renal segment of the aorta and renal arteries is provided. Features of pharmacological nephroprotection, perfusion methods of kidney protection, and a brief historical review of bypass operations on the renal arteries are presented.

Pre-treatment with pregabalin reduces liver ischemia-reperfusion injury in rats: tissue protection with an analgesic.

Ischemia-reperfusion injury is thought to be the most important factor affecting the success of liver surgery. Pregabalin has been studied to prevent ischemic reperfusion injury in many organs. The aim of this study was to investigate the role of pregabalin in preventing liver ischemic injury. 40 male Wistar-Albino rats, 6-8 weeks old, were divided into 5 groups. Four groups other than the sham group were subjected to hepatic ischemia for 1 hour, followed by 2 hours of reperfusion. Effects of 30 mg/and 60 mg/kg pregabalin were evaluated by aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor α (TNF-α), nuclear factor-kappa B (NF-кB), interleukin (IL)-6 levels, measured in blood samples collected before and after ischemia. Apoptosis was measured by caspase-3, and tissue samples were evaluated for ischemia by histopathologic examination. The 60 mg pregabalin group was significantly superior (p=0.024) to the N-acetylcysteine group and the 30 mg pregabalin group for AST levels (p=0.612 and p=0.807, respectively). The difference between before and after ischemia-reperfusion blood TNF-α levels was higher in the 60 mg pregabalin group, but not significantly different from the 30 mg pregabalin and N-acetylcysteine groups (p>0.05). Tissue TNF-α levels showed that 60 mg and 30 mg pregabalin treatment was more effective than no-treatment (p=0.011, p=0.033, respectively), but not superior to N-acetylcysteine (p>0.05). It has been found that ischemia-reperfusion causes damage to the liver, and this damage may be irreversible if no treatment is given. Our study group, pregabalin molecule was found to be significantly effective in preventing ischemia-reperfusion injury and may have a therapeutic advantage over N-acetylcysteine.

Effect and possible mechanisms of saponins in Chinese herbal medicine exerts for the treatment of myocardial ischemia-reperfusion injury in experimental animal: a systematic review and meta-analysis.

Preventing ischemia-reperfusion injury is the main direction of myocardial infarction treatment in the convalescent stage. Some studies have suggested that saponins in Traditional Chinese medicine (TCM) preparations can protect the myocardium by various mechanisms. Our meta-analysis aims to evaluate the efficacy of TCM saponins in treating myocardial ischemia-reperfusion injury (MIRI) and to summarize the potential molecular mechanisms further. We conducted a literature search in six electronic databases [Web of Science, PubMed, Embase, Cochrane Library, Sinomed, China National Knowledge Infrastructure (CNKI)] until October 2022. Seventeen eligible studies included 386 animals (254 received saponins and 132 received vehicles). The random effect model is used to calculate the combined effect. The effect size is expressed as the weighted average difference (WMD) and 95% confidence interval (CI). Compared with placebo, saponins preconditioning reduced infarct size after MIRI significantly (WMD: -3.60,95% CI: -4.45 to -2.74, P < 0.01, I2: 84.7%, P < 0.001), and significantly increased EF (WMD: 3.119, 95% CI: 2.165 to 4.082, P < 0.01, I2: 82.9%, P < 0.0 L) and FS (WMD: 3.157, 95% CI: 2.218 to 4.097, P < 0.001, I2: 81.3%, P < 0.001). The results show that the pre-administration of saponins from TCM has a significant protective effect on MIRI in preclinical studies, which provides an application prospect for developing anti-MIRI drugs with high efficiency and low toxicity.

Protective Effects of Syringic Acid on Ischemia-Reperfusion Injury in Testicular Torsion: An Experimental Study in a Rat Model.

The purpose of this study was to assess the effectiveness of syringic acid in preventing ischemia-reperfusion injury following detorsion in a rat model of induced testicular torsion. In our study, a total of 24 rats, eight in each group, were used. Group 1 served as the control group. Group 2 underwent testicular torsion and detorsion. Group 3 underwent the same procedures as Group 2, but also received 100 mg/kg syringic acid immediately following ischemia. Spectrophotometric analysis was performed on blood samples, and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as the values of malondialdehyde (MDA), were evaluated under direct microscopic examination of the testis to determine tissue injury. The architecture of the seminiferous tubules and spermatogenesis processes were graded using the Johnsen and Cosentino scoring systems. The mean value of MDA was higher in Group 2 compared to the other groups (p < 0.001). Group 3 demonstrated a decline in the concentrations of proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta, as indicated by biochemical analysis of blood samples, when compared to Group 2 (p-values: 0.045, 0.001, and <0.001, respectively). In addition, the improvement in Johnsen and Cosentino scores was significantly higher in Group 3 compared to Group 2 (p = 0.028 and p = 0.001, respectively). These findings suggest that syringic acid has a protective effect against testicular oxidative damage.

SERCA2 phosphorylation at serine 663 is a key regulator of Ca2+ homeostasis in heart diseases

Despite advances in cardioprotection, new therapeutic strategies capable of preventing ischemia-reperfusion injury of patients are still needed. Here, we discover that sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA2) phosphorylation at serine 663 is a clinical and pathophysiological event of cardiac function. Indeed, the phosphorylation level of SERCA2 at serine 663 is increased in ischemic hearts of patients and mouse. Analyses on different human cell lines indicate that preventing serine 663 phosphorylation significantly increases SERCA2 activity and protects against cell death, by counteracting cytosolic and mitochondrial Ca2+ overload. By identifying the phosphorylation level of SERCA2 at serine 663 as an essential regulator of SERCA2 activity, Ca2+ homeostasis and infarct size, these data contribute to a more comprehensive understanding of the excitation/contraction coupling of cardiomyocytes and establish the pathophysiological role and the therapeutic potential of SERCA2 modulation in acute myocardial infarction, based on the hotspot phosphorylation level of SERCA2 at serine 663 residue.

Exosomes obtained from adipose mesenchymal stem cells prevent ischemia-reperfusion injury after torsion-detorsion in rat testes.

To investigate the effect of exosomes obtainedfrom adipose-derived mesenchymal stem cells (AD-MSCs) on testicular ischemia-reperfusion (I/R) injury. AD-MSCs from rat adipose tissue were cultured. Characterization of cells was evaluated with CD44, CD90, CD34 and CD45 antibodies. Exosomes from AD-MSCs were obtained with the miRCURYexosomeisolation kit. 21 rats were divided into 3 groups. The I/R model was created as 720° torsion for 4h and reperfusion for 4h. In the Sham group (SG), only scrotal incision was made. 100µl of medium in the torsion-control group (T-CG) and 100µl of exosome in the treatment group (TG) were injected into the testicular parenchyma after detorsion. Johnsen scores of testicles were determined. Apoptosis was evaluated by the TUNEL method. It was observed that the seminiferous tubule structures were partially disrupted in T-CG, but normal in SG and TG. Johnsen scores in SG, T-CG, and TG were 8.64 ± 0.39, 7.71 ± 0.37, and 8.57 ± 0.39, respectively. Apoptotic cell distribution was 11.28 ± 5.25%, 60.58% ± 1.68% and 17.71 ± 8.34% in SG, T-CG and TG, respectively. In both parameters, the difference between SG and TG was insignificant (p > 0.05), the difference between T-CG/TG and SG/T-CG was significant (p < 0.05). Exosomes obtainedfromAD-MSCs are effective in preventing testicular I/R injury. This effect appears to occur because of suppression of apoptotic activity.

Liraglutide alleviates myocardial ischemia‒reperfusion injury in diabetic mice

Diabetic patients are prone to acute myocardial infarction. Although reperfusion therapy can preserve the viability of the myocardium, it also causes fatal ischemia‒reperfusion injury. Diabetes can exacerbate myocardial ischemia‒reperfusion injury, but the mechanism is unclear. We aimed to characterize the effects of liraglutide on the prevention of ischemia‒reperfusion injury and inadequate autophagy. Liraglutide reduced the myocardial infarction area and improved cardiac function in diabetic mice. We further demonstrated that liraglutide mediated these protective effects by activating AMPK/mTOR-mediated autophagy. Liraglutide markedly increased p-AMPK levels and the LC3 II/LC3 I ratio and reduced p-mTOR levels and p62 expression. Pharmacological inhibition of mTOR increased cell viability and autophagy levels in high glucose and H/R-treated H9C2 cells. Overall, our study reveals that liraglutide acts upstream of the AMPK/mTOR pathway to effectively counteract high glucose- and H/R-induced cell dysfunction by activating AMPK/mTOR-dependent autophagy, providing a basis for the clinical prevention and treatment of ischemia‒reperfusion in diabetes.

Peptide Sodium Channels Modulator Mu-Agatoxin-Aa1a Prevents Ischemia-Reperfusion Injury of Cells

Ischemia-reperfusion injury (IRI) is an irreversible functional and structural injury. Restoration of normal oxygen concentration exacerbates the emergence and development of deadly cells. One of the possible moments of reperfusion damage to cells is an increase in the intracellular concentration of sodium ions. In this article, we study the mu-agatoxin-Aa1a, a modulator of sodium channels, on the processes of IRI cells damage. The toxin was synthesized using an automatic peptide synthesizer. Hypoxia was induced by reducing the content of serum and oxygen in the CHO-K1 culture. The influence of the toxin on the level of apoptosis; intracellular concentration of sodium, calcium, and potassium ions; intracellular pH; totality of reactive oxygen species (ROS), nitric oxide (NO), and ATP; and changes in the mitochondrial potential were studied. The experiments performed show that mu-agatoxin-Aa1a effectively prevents IRI of cells. Toxin reduces the level of apoptosis and prevents a decrease in the intracellular concentration of sodium and calcium ions during IRI. Mu-agatoxin-Aa1a contributes to the maintenance of elevated intracellular pH, reduces the intracellular concentration of ROS, and prevents the decrease in intracellular NO concentration and mitochondrial potential under conditions of reoxygenation/reperfusion. An analysis of experimental data shows that the mu-agatoxin-Aa1a peptide has adaptogenic properties. In the future, this peptide can be used to prevent ischemia/reperfusion tissue damage different genesis.

Preventing ischemia-reperfusion injury by acousto-mechanical local oxygen delivery.

Ischemia-reperfusion (I/R) injury is a pathological process that causes vascular damage and dysfunction which increases recurrence and/or mortality in myocardial infarction, ischemic stroke, and organ transplantation. We hypothesized that ultrasound-stimulated oxygen-loaded microbubble (O2-MB) cavitation would enhance mechanical force on endothelium and simultaneously release oxygen locally at the targeted vessels. This cooperation between biomechanical and biochemical stimuli might modulate endothelial metabolism, providing a potential clinical approach to the prevention of I/R injury. Murine hindlimb and cardiac I/R models were used to demonstrate the feasibility of injury prevention by O2-MB cavitation. Increased mechanical force on endothelium induced eNOS-activated vasodilation and angiogenesis to prevent re-occlusion at the I/R vessels. Local oxygen therapy increased endothelial oxygenation that inhibited HIF-1α expression, increased ATP generation, and activated cyclin D1 for cell repair. Moreover, a decrease in interstitial H2O2 level reduced the expression of caspase3, NFκB, TNFα, and IL6, thus ameliorating inflammatory responses. O2-MB cavitation showed efficacy in maintaining cardiac function and preventing myocardial fibrosis after I/R. Finally, we present a potential pathway for the modulation of endothelial metabolism by O2-MB cavitation in relation to I/R injury, wound healing, and vascular bioeffects.

An update on the molecular mechanism and pharmacological interventions for Ischemia-reperfusion injury by regulating AMPK/mTOR signaling pathway in autophagy

AMP-activated protein kinase (5’-adenosine monophosphate-activated protein kinase, AMPK)/mammalian target of rapamycin (mTOR) is an important signaling pathway maintaining normal cell function and homeostasis in vivo. The AMPK/mTOR pathway regulates cellular proliferation, autophagy, and apoptosis. Ischemia-reperfusion injury (IRI) is secondary damage that frequently occurs clinically in various disease processes and treatments, and the exacerbated injury during tissue reperfusion increases disease-associated morbidity and mortality. IRI arises from multiple complex pathological mechanisms, among which cell autophagy is a focus of recent research and a new therapeutic target. The activation of AMPK/mTOR signaling in IRI can modulate cellular metabolism and regulate cell proliferation and immune cell differentiation by adjusting gene transcription and protein synthesis. Thus, the AMPK/mTOR signaling pathway has been intensively investigated in studies focused on IRI prevention and treatment. In recent years, AMPK/mTOR pathway-mediated autophagy has been found to play a crucial role in IRI treatment. This article aims to elaborate the action mechanisms of AMPK/mTOR signaling pathway activation in IRI and summarize the progress of AMPK/mTOR-mediated autophagy research in the field of IRI therapy.

Effect of ischemic preconditioning on skeletal tissue tolerance after warm venous ischemia

Free muscular flaps are commonly used in plastic surgery. The main reason of failure is thrombosis induced by a phenomenon called ischemia reperfusion. Preconditioning showed an interest to prevent ischemia reperfusion injury in transplantation surgery. The aim of the study is to evaluate the effect of ischemic preconditioning on skeletal tissue tolerance after warm venous ischemia. We realized an experimental study with latissimus dorsi flaps of 12 pigs, divided in 6 groups in function of their time of preconditioning and duration of warm venous ischemia. A morphologic analysis was performed measuring cell's diameter and interstitial tissue area and notifying the presence or absence of neutrophils, necrosis or intravascular thrombosis. To detect inflammation, necrosis or hypoxia, immunohistochemistry was effectuated using the follow primary antibodies, AIF, HIF1 alpha, caspase 3, SOD 1 and PKC epsilon. TUNEL assay showed apoptosis cells, were realized. One way Anova test was performed to compare the quantitative evolution over time of histological parameters and rate of apoptosis. Preconditioning of 40min or 1hour allowed to reduced ischemia reperfusion lesions: no cellular or interstitial oedema, reduction of neutrophils infiltrate and intravascular thrombus. TUNEL assay showed a higher rate of apoptosis nucleus for the control group E compared to preconditioning group C and D. Immunohistochemistry results were no relevant. We showed a diminution of lesions of ischemia reperfusion for experimental groups with preconditioning: diminution of interstitial oedema, of cellular oedema, diminution of neutrophils infiltrated and level of apoptosis cells. Preconditioning of 40minutes were as efficient as one hour.

The Neuroprotective Effects of Ginsenoside Rd Pretreatment in a Rat Model of Spinal Cord Ischemia-Reperfusion Injury.

Paraplegia may develop as a result of spinal cord ischemia-reperfusion injury in patients who underwent thoracoabdominal aortic surgery. The objective of this research is to determine the neuroprotective effects of ginsenoside Rd pretreatment in a rat model of spinal cord ischemia-reperfusion injury. Sprague-Dawley rats (n=36) were randomly assigned to three groups. The sham (n=12) and control (n=12) groups received normal saline orally. The Rd group (n=12) received ginsenoside Rd (100 mg/kg) orally 48 hours before the induction of spinal cord ischemia. Spinal cord ischemia was induced by aortic occlusion using a Fogarty balloon catheter in the Rd and control groups. A neurological assessment according to the motor deficit index and a histological evaluation of the spinal cord were performed. To evaluate the antioxidant activity of ginsenoside Rd, malondialdehyde levels and superoxide dismutase activity were determined. Further, the tissue levels of tumor necrosis factor-alpha and interleukin-1 beta were measured. The Rd group showed significantly lower motor deficit index scores than did the control group throughout the entire experimental period (P<0.001). The Rd group demonstrated significantly greater numbers of normal motor neurons than did the control group (P=0.039). The Rd group exhibited decreased malondialdehyde levels (P<0.001) and increased superoxide dismutase activity (P=0.029) compared to the control group. Tumor necrosis factor-alpha and interleukin-1 beta tissue levels were significantly decreased in the Rd group (P<0.001). Ginsenoside Rd pretreatment may be a promising treatment to prevent ischemia-reperfusion injury in patients who undergo thoracoabdominal aortic surgery.

The Prevention of Ischemia-Reperfusion Injury in Elderly Rats after Lower Limb Tourniquet Use.

Background: Lower limb ischemia-reperfusion injury (IRI-LL) is a common major complication of orthopedic surgery, especially in elderly patients. It has previously been demonstrated that folinic acid (FA) reduced IRI-LL damage in 3–4-month-old rats. This current work analyses the effect of FA in the prevention of IRI-LL in elderly animals. Methods: Forty-two 18-month-old male WAG/RijHsd rats were subjected to 3 h of ischemia. Eighteen animals received FA (2.5 mg/kg, ip) 20 min before the end of the ischemia period, while the other half received the same volume of saline solution. The animals were sacrificed after 3 h, 24 h, and 14 days of reperfusion for biochemical (tissue damage markers and electrolytes), histopathological studies of the gastrocnemius muscle and the daily assessment of the limb function by the Rota Rod test, respectively. Results: The administration of FA prior to the end of the ischemia period reduced the increase in LDH and CK observed in non-treated animals by 30–40% (p < 0.0001). When the histological sections were analyzed, FA was found to have reduced the number of damaged muscle fibers per field by 20% (60 ± 17.1 vs. 80.7 ± 16.4, p < 0.0001). The functional test revealed that FA also led to an improvement in the muscle function, assessed by the length of time that the animals kept running on the rod, compared to untreated animals. Conclusions: The administration of FA, prior to the end of the ischemic period, decreases the damage induced by IRI-LL, also achieving a faster recovery of mobility.

Effects of polyethylene glycol-20k IV solution on donor management in a canine model of donor brain death.

Traditionally, vasopressors and crystalloids have been used to stabilize brain dead donors; however, the use of crystalloid is fraught with complications. This study aimed to investigate the effectiveness of a newly developed impermeant solution, polyethylene glycol-20k IV solution (PEG-20k) for resuscitation and support of brain dead organ donors. Brain death was induced in adult beagle dogs and a set volume of PEG-20k or crystalloid solution was given thereafter. The animals were then resuscitated over 16h with vasopressors and crystalloid as necessary to maintain mean arterial pressure of 80-100mmHg. The kidneys were procured and cold-stored for 24h, after which they were analyzed using the isolated perfused kidney model. The study group required significantly less crystalloid volume and vasopressors while having less urine output and requiring less potassium supplementation than the control group. Though the two groups' mean arterial pressure and lactate levels were comparable, the study group's kidneys showed less preservation injury after short-term reperfusion indexed by decreased lactate dehydrogenase release and higher creatinine clearance than the control group. The use of polyethylene glycol-20k IV solution for resuscitating brain dead donors decreases cell swelling and improves intravascular volume, thereby improving end organ oxygen delivery before procurement and so preventing ischemia-reperfusion injury after transplantation.

Selective Brain Cooling: A New Horizon of Neuroprotection.

Therapeutic hypothermia (TH), which prevents irreversible neuronal necrosis and ischemic brain damage, has been proven effective for preventing ischemia-reperfusion injury in post-cardiac arrest syndrome and neonatal encephalopathy in both animal studies and clinical trials. However, lowering the whole-body temperature below 34°C can lead to severe systemic complications such as cardiac, hematologic, immunologic, and metabolic side effects. Although the brain accounts for only 2% of the total body weight, it consumes 20% of the body's total energy at rest and requires a continuous supply of glucose and oxygen to maintain function and structural integrity. As such, theoretically, temperature-controlled selective brain cooling (SBC) may be more beneficial for brain ischemia than systemic pan-ischemia. Various SBC methods have been introduced to selectively cool the brain while minimizing systemic TH-related complications. However, technical setbacks of conventional SBCs, such as insufficient cooling power and relatively expensive coolant and/or irritating effects on skin or mucosal interfaces, limit its application to various clinical settings. This review aimed to integrate current literature on SBC modalities with promising therapeutic potential. Further, future directions were discussed by exploring studies on interesting coping skills in response to environmental or stress-induced hyperthermia among wild animals, including mammals and birds.

The effect of melatonin on cardiac biomarkers after coronary artery bypass graft surgery: A double-blind, randomized pilot study

Melatonin has emerged as an anti-inflammatory agent, potent direct free-radical scavenger, and an indirect antioxidant in preventing ischemia-reperfusion injury. This study aimed to evaluate melatonin's effect on cardiac biomarkers after coronary artery bypass grafting (CABG). A double-blind, randomized placebo-controlled pilot clinical study. Booali Sina Hospital, Qazvin University of Medical Sciences, Qazvin, Iran. One hundred patients undergoing elective CABG. The patients were divided randomly into control (C) and melatonin (M) groups (50 patients per group). The M group received 3 mg of melatonin the night before surgery, 3 mg in the morning, and routine cardiac surgery medications. The C group received 1 placebo tablet rather than melatonin. After surgery, the patients in the M group received 3 mg of melatonin, and the C group received 1 placebo tablet at bedtime until the third day after CABG. In both groups, creatine kinase-MB (CPK-MB), cardiac troponin I, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were measured before surgery and on the first, second, and third postoperative days. Serum CPK-MB levels on the second and third day after CABG were significantly lower in the M group than in the C group (p < 0.05). Regarding cardiac troponin I, CRP, and ESR markers, there were no significant changes in serum concentration before surgery and on the first, second, and third days after surgery between the 2 groups (p > 0.05). The mean length of hospitalization in the ICU was lower in the M group (3.4 ± 1.05) compared with the C group (3.96 ± 1.06, p=0.01). Melatonin reduced the postoperative level of CPK-MB and the length of hospitalization in the ICU in patients who underwent cardiac surgery.