Period Of Ischemia Research Articles

Mitochondrial respiratory pathways in immature rat heart tissue using different cardioplegic solutions.

Minor defects in the mitochondrial ATP-generating system and post-cardioplegia oxidative phosphorylation can negatively impact cardiac function in immature hearts. This study aimed to examine the mitochondrial respiratory pathway using three different cardioplegic solutions (Custodiol HTK, St. Thomas, and Del Nido) during moderate (1h) and long (3h) ischemic periods. A total of 41 male Wistar albino rats were utilized in this study. Five experiments were conducted without the use of any cardioplegic solution (CP0 group). To assess both moderate and prolonged ischemic periods, six experiments were carried out in each of the following groups: CP1 group (St. Thomas solution), CP2 group (Custodiol HTK solution), and CP3 group (Del Nido solution). After 1h, the highest mitochondrial respiration rate was observed in the CP3 group and the lowest in the CP1 group (p = 0.006). After adding ADP substrate, the highest mitochondrial ATP-production-coupled respiration was recorded in the CP3 group, which was similar to the control group CP0. After 3h, while evaluating the ratio between mitochondrial respiration ATP-production coupled and basal respiration, significant differences were found between CP1 group and CP3 group (p = 0.035), as well as between the CP1 and CP0 groups (p = 0.045). Additionally, by assessing the condition of the outer mitochondrial membrane using the Cyt C effect (Cyt/Phos [ADP]), significant differences were observed between the CP1 and CP3 group (p = 0.004), as well as between CP1 and CP0 groups (p = 0.003). Del Nido cardioplegic solution provided optimal mitochondrial protection under moderate and long myocardial ischemia conditions.

The Rapidly Evolving Landscape of DCD Heart Transplantation.

To summarise current international clinical outcomes from donation after circulatory death heart transplantation (DCD-HT); discuss procurement strategies, their impact on outcomes and overall organ procurement; and identify novel approaches and future areas for research in DCD-HT. Globally, DCD-HT survival outcomes (regardless of procurement strategy) are comparable to heart transplantation from brain dead donors (BDD). Experience with normothermic machine perfusion sees improvement in rates of primary graft dysfunction. Techniques have evolved to reduce cold ischaemic exposure to directly procured DCD hearts, though controlled periods of cold ischaemia can likely be tolerated. There is interest in hypothermic machine perfusion (HMP) for directly procured DCD hearts, with promising early results. Survival outcomes are firmly established to be equivalent between BDD and DCD-HT. Procurement strategy (direct procurement vs. regional perfusion) remains a source of debate. Methods to improve allograft warm ischaemic tolerance are of interest and will be key to the uptake of HMP for directly procured DCD hearts.

Tanshinone IIA Against Cerebral Ischemic Stroke and Ischemia-Reperfusion Injury: A Review of the Current Documents.

Stroke is a well-known neurological disorder that carries significant morbidity and mortality rates worldwide. Cerebral Ischemic Stroke (CIS), the most common subtype of stroke, occurs when thrombosis or emboli form elsewhere in the body and travel to the brain, leading to reduced blood perfusion. Cerebral Ischemia/Reperfusion Injury (CIRI) is a common complication of CIS and arises when blood flow is rapidly restored to the brain tissue after a period of ischemia. The therapeutic approaches currently recognized for CIS, such as thrombolysis and thrombectomy, have notable side effects that limit their clinical application. Recently, there has been growing interest among researchers in exploring the potential of herbal agents for treating various disorders and malignancies. One such herbal agent with medicinal applications is tanshinone IIA, an active diterpene quinone extracted from Salvia miltiorrhiza Bunge. Tanshinone IIA has shown several pharmacological benefits, including anti-inflammatory, antioxidant, anti-apoptotic, and neuroprotective properties. Multiple studies have indicated the protective role of tanshinone IIA in CIS and CIRI. This literature review aims to summarize the current findings regarding the molecular mechanisms through which this herbal compound improves CIS and CIRI.

Neuroprotective effect of Bouvardia ternifolia (Cav.) Schltdl via inhibition of TLR4/NF-κB, caspase-3/Bax/Bcl-2 pathways in ischemia/reperfusion injury in rats.

Bouvardia ternifolia is a plant known for its traditional medicinal uses, particularly in treating inflammation and oxidative stress. Recent studies have explored its potential in neuroprotection, especially in the context of cerebral ischemia/reperfusion injury, a condition where blood supply returns to the brain after a period of ischemia, leading to oxidative stress and inflammation. This damage is a major contributor to neuronal death and neurodegenerative diseases. A BCCAO/reperfusion model was induced, followed by treatment with B. ternifolia extract. Various molecular biology methods were employed, including Western blot analysis, gene expression assessment via RT-qPCR, and the measurement of oxidative stress mediators. In the BCCAO/reperfusion model, the compounds in the dichloromethane extract work by targeting various signaling pathways. They prevent the activation of iNOS and nNOS, reducing harmful reactive oxygen and nitrogen species, and boosting antioxidant enzymes like catalase and superoxide dismutase. This lowers oxidative stress and decreases the expression of proteins and genes linked to cell death, such as Bax, Bcl-2, and caspase-3. The extract also blocks the TLR4 receptor, preventing NF-κB from triggering inflammation. Additionally, it reduces the activation of microglia and astrocytes, as shown by lower levels of glial activation genes like GFAP and AiF1. The dichloromethane extract of B. ternifolia demonstrated significant neuroprotective effects in the BCCAO/reperfusion model by modulating multiple signaling pathways. It effectively reduced oxidative stress, inhibited inflammation, and attenuated apoptosis, primarily through the downregulation of key proteins and genes associated with these processes. These findings suggest that the extract holds therapeutic potential for mitigating ischemia/reperfusion-induced neuronal damage.

Methods and Strategies of Microsurgery Combined with Ilizarov Technique in the Treatment of Amputation of Limbs in Renji Hospital: A Report of 51 Cases.

Severe limb amputation trauma often results in bone and soft tissue defects after debridement. Traditional replantation aims to save the limb by shortening the ischemic period and using autologous transplantation for repair, but it can lead to surgical trauma, donor site damage, and prolonged operation time. Due to contusion, pollution, and complex injury, there is no unified standard for replantation and fixation. Improper operation can easily lead to complications such as bone infection, nonunion, bone defect, and joint stiffness. This study introduces the Ilizarov technique into microsurgery to improve limb lengthening after reconstruction and standardizes the steps of replantation fixation for complex limb avulsion injuries, with a focus on clinical efficacy. A retrospective analysis was performed on 51 patients with complex limb amputation who were treated in Zhengzhou Renji Hospital from June 2009 to March 2021. On the basis of microsurgical limb replantation, Ilizarov technology was introduced to innovate the internal and external combined stepwise fixation method for replantation. Patients' gender, age, height, weight, BMI, and other general information were collected. X-ray films were reviewed regularly to observe the surgical healing of fracture, that is, the degree of limb shortening. The lengthening time, carrying time after lengthening, follow-up time, Dahl classification, Paley fracture healing classification, and Chen Zhongwei's replantation function score were used to evaluate the recovery of the affected limb. A total of 51 patients were included in this group, including 36 male patients and 15 female patients. All the amputated wounds were single limb amputation. In this group of patients, the hind limbs were shortened by 2-12.5 cm (5.32 ± 2.24) after replantation. A total of 44 patients whose hind limbs were shortened by more than 2.5 cm were treated with two-stage Ilizarov lengthening for 1.5-5.5 months (3.19 ± 1.03). The carrying time was 3-7.5 months (4.25 ± 0.94), and the follow-up time was 1-7.8 years (3.76 ± 1.69). Among the 49 survived patients, the Dahl grade of external fixation was less than Grade 2 in 89.8%. The excellent and good rate of Paley fracture healing classification was 89.8%. The excellent and good rate of Chen Zhongwei's limb replantation function classification was 79.6%. Microsurgery combined with Ilizarov technique in the treatment of limb amputation injury, limb salvage reconstruction with internal and external combined step-by-step combined fixation, and one-stage shortening and two-stage limb lengthening can reduce the occurrence of osteomyelitis, bone defect and nonunion, expand the indications of limb replantation, improve the success rate of limb replantation, with satisfactory results, and facilitate the promotion of clinical techniques.

Therapeutic Correlation of TLR-4 Mediated NF-κB Inflammatory Pathways in Ischemic Injuries.

Ischemia-reperfusion (I/R) injury refers to the tissue damage that happens when blood flow returns to tissue after a period of ischemia. I/R injuries are implicated in a large array of pathological conditions, such as cerebral, myocardial, renal, intestinal, retinal and hepatic ischemia. The hallmark of these pathologies is excessive inflammation. Toll-like receptors (TLRs) are recognized as significant contributors to inflammation caused by pathogens and, more recently, inflammation caused by injury. TLR-4 activation initiates a series of events that results in activation of nuclear factor kappa-B (NF-κB), which stimulates the production of pro-inflammatory cytokines and chemokines, exacerbating tissue injury. Therefore, through a comprehensive review of current research and experimentation, this investigation elucidates the TLRs signalling pathway and the role of TLR-4/NF-κB in the pathophysiology of I/R injuries. Furthermore, this review highlights the various pharmacological agents (TLR-4/NF-κB inhibitors) with special emphasis on the various ischemic injuries (cerebral, myocardial, renal, intestinal, retinal and hepatic). Future research should prioritise investigating the specific molecular pathways that cause TLR-4/NF-κBmediated inflammation in ischemic injuries. Additionally, efforts should be made to enhance treatment approaches in order to enhance patient outcomes.

Neutrophil extracellular traps and citrullinated fibrinogen contribute to injury in a porcine model of limb ischemia and reperfusion.

Ischemia/reperfusion injury (IRI) is a complex pathological process, triggered by the restoration of blood flow following an interrupted blood supply. While restoring the blood flow is the only option to salvage the ischemic tissue, reperfusion after a prolonged period of ischemia initiates IRI, triggering a cascade of inflammatory responses ultimately leading to neutrophil recruitment to the inflamed tissue, where they release neutrophil extracellular traps (NETs). NETs are web-like structures of decondensed chromatin and neutrophilic proteins, including peptidyl-arginine deiminase 2 and 4 (PAD2, PAD4), that, once outside, can citrullinate plasma proteins, irreversibly changing their conformation and potentially their function. While the involvement of NETs in IRI is known mainly from rodent models, we aimed to determine the effect of NET formation and especially PADs-mediated extracellular protein citrullination in a porcine model of limb IRI. We conducted our study on amputated pig forelimbs exposed to 1h or 9h of ischemia and then reperfused in vivo for 12h. Limb weight, edema formation, compartmental pressure were measured, and skeletal muscle was analyzed by immunofluorescence (TUNEL assay and dystrophin staining) to evaluate tissue damage. Fibrin tissue deposition, complement deposition and NETs were investigated by immunofluorescence. Citrullinated plasma proteins were immunoprecipitated and citrullinated fibrinogen was identified in the plasma by Western blot and in the tissue by immunofluorescence and Western blot. Our data consolidate the involvement of NETs in a porcine model of limb IRI, correlating their contribution to damage extension with the duration of the ischemic time. We found a massive infiltration of NETs in the group subjected to 9h ischemia compared to the 1h and citrullinated fibrinogen levels, in plasma and tissue, were higher in 9h ischemia group. We propose fibrinogen citrullination as one of the mechanisms contributing to the worsening of IRI. NETs and protein citrullination represent a potential therapeutic target, but approaches are still a matter of debate. Here we introduce the idea of therapeutic approaches against citrullination to specifically inhibit PADs extracellularly, avoiding the downstream effects of hypercitrullination and keeping PADs' and NETs' intracellular regulatory functions.

Hand Digit Revascularization: Could Be an "Elective-Urgence" Surgery?

Background: A continuous obstacle that has limited access to and implementation of finger replantation surgery is timeliness, as ischemia time is traditionally considered a crucial factor for success. However, claims that the vitality of amputated fingers decreases after 6 h of warm ischemia and 12 h of cold ischemia are mostly based on theoretical considerations. Methods: Here we present a case of multi-digit revascularization after 72 h of warm ischemia using the microsurgical arteriovenous bypass technique. Results: In the reported case, revascularization was performed after a long ischemic period and showed good recovery of motor and sensory function. Conclusions: We identified significant limitations in the literature supporting time limits of ischemia and recent evidence demonstrating the feasibility of delayed finger replantation. The current treatment approach for amputation injuries often requires transfers or nighttime emergency procedures, increasing costs and limiting the national availability of finger replantation. Changes to finger replantation protocols based on evidence could expand access to this service and improve the quality of care.

Protective effects of mesenchymal stem cells-derived extracellular vesicles against ischemia-reperfusion injury of hearts donated after circulatory death: Preliminary study in a pig model

IntroductionInsufficient supply of cardiac grafts represents a severe obstacle in heart transplantation. Donation after Circulatory Death (DCD), in addition to conventional donation after brain death, is one promising option to overcome the organ shortage. However, DCD organs undergo an inevitable more extended period of warm unprotected ischemia between circulatory arrest and graft procurement. Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) have shown remarkable protective effects against ischemia-reperfusion injury. Thus, we aimed to enhance grafts preservation from DCD donors, through treatment with MSC-EVs. MethodsFemale pigs were euthanized by barbiturate overdose and after 20 min of a flat EKG, the chest was opened, the heart harvested and subsequently connected to an extracorporeal perfusion machine. MSC-EVs, isolated by ion exchange chromatography, were added to the perfusion solution (1×1011 particles) and the heart was perfused for 2 h. Then, heart tissue biopsies were taken to assess histological changes, mitochondrial morphology, antioxidant enzyme activity and inflammation mediators’ expression. Biochemical parameters of myocardial viability were assessed in the perfusate. ResultsThe treatment with MSC-EVs significantly prevented mitochondria swelling, mitochondrial cristae loss and oxidative stress in cardiac tissue. The protective effect of MSC-EVs was confirmed by the delayed increase of the cardiac-specific enzymes CK and TnC in the perfusate and the reduction of caspase-3+ cells in tissue sections. ConclusionMSC-EVs improve graft quality by preserving the mitochondrial ultrastructure protecting the myocardium against oxidative stress, reducing apoptosis of cardiac cells and preventing the increase of pro-inflammatory cytokines.

Power-Doppler Ultrasonic Imaging of Peripheral Perfusion in Diabetic Mice.

We explored the capabilities of power-Doppler ultrasonic (PD-US) imaging without contrast enhancement for monitoring changes in muscle perfusion over time. Ischemic recovery was observed in healthy and type II diabetic male and female mice with and without exercise. In separate studies, perfusion was measured during and after 5-min ischemic periods and during four-week recovery periods following irreversible femoral ligation. A goal was to assess how well PD-US estimates tracked the diabetic-related changes in endothelial function that influenced perfusion. The average perfusion recovery time following femoral ligation increased 47% in diabetic males and 74% in diabetic females compared with non-diabetic mice. Flow-mediated dilation in conduit arteries and the reactive hyperemia index in resistive vessels each declined by one half in sedentary diabetic mice compared with sedentary non-diabetic mice. We found that exercise reduced the loss of endothelial function from diabetes in both sexes. The reproducibility of perfusion measurements was limited primarily by our ability to select the same region in muscle and to effectively filter tissue clutter. PD-US measurements can precisely follow site-specific changes in skeletal muscle perfusion related to diabetes over time, which fills the need for techniques capable of regularly monitoring atherosclerotic changes leading to ischemic vascular pathologies.

Can Apigenin Be an Effective Therapeutic Agent Against Experimental Renal Ischemia-Reperfusion Injury?

Aim: This study aims to reveal the effects of two doses of apigenin (API) against renal ischemia-reperfusion injury (R I/R). Material and Methods: For this purpose, 5 and 10 mg/kg doses of API were preferred in our study, and the groups were designed as sham, R I/R, 5 mg/kg API, and 10 mg/kg API groups for the implementation of the experimental protocol. In the R I/R model, 1-hour ischemia and 24-hour reperfusion periods were preferred. Oxidative and inflammatory markers were measured biochemically in samples taken at the end of the experiment. Results: Biochemical results showed that oxidative and inflammatory markers increased significantly in the R I/R group, but antioxidant activities decreased significantly. In the 5 and 10 mg/kg API groups, R I/R damage was alleviated considerably, with these markers approaching the sham group values. Conclusion: As a result, the study's results determined that two different doses of API were effective against R I/R-induced kidney damage.

Optimizing DCD Liver Grafts With Prolonged Warm Ischemic Time Using Stabilized Plasmin in a Static Cold Storage Orthotopic Rat Liver Transplant Model.

The clinical success of liver transplantation has led to increased demand, requiring further expansion of the donor pool. Therapeutic interventions to optimize organs from donation after circulatory death (DCD) have significant potential to mitigate the organ shortage. Dysfunction in DCD liver grafts is mediated by microvascular thrombosis during the warm ischemic period, and strategies that reduce this thrombotic burden may improve graft function. We hypothesized that the administration of the fibrinolytic enzyme plasmin to the donor organ during the cold storage period would reduce the thrombotic burden and improve DCD liver graft function. In 2 separate cohorts, 32 syngeneic orthotopic rat liver transplants were performed in Lewis rats. Livers were procured from donors with 45 min of warm ischemic injury. Liver grafts were flushed with histidine-tryptophan-ketoglutarate preservation solution mixed with either plasmin (experimental group) or albumin (control group). All investigators were blinded to treatment group. After preparing the liver for implant using a modified cuff technique, the liver was stored for 1 h by static cold storage at 4 °C. Immediately before implantation, the liver graft was flushed, and this effluent was analyzed for fibrin degradation products to determine graft clot burden. Twenty-four hours following transplantation, animals were euthanized, and samples were collected. Recipient survival was significantly higher for DCD liver grafts treated with plasmin compared with control. Moreover, histology of liver graft tissue immediately before implant reflected significantly reduced congestion in plasmin-treated livers (score, mean ± SD: 0.73 ± 0.59 versus 1.12 ± 0.48; P = 0.0456). The concentration of fibrin degradation products in the final flush before implantation was significantly reduced in plasmin-treated livers (743 ± 136 versus 10 919 ± 4642 pg/mL; P = 0.0001), reflecting decreased clot burden in the graft. The present study demonstrates that plasmin improves survival and may reduce thrombotic burden in DCD liver grafts with prolonged warm ischemic injury, meriting further study.

Oxygenated versus non-oxygenated flush out during deceased donor liver procurement: The first proof-of-concept study in humans.

Liver transplantation is used for treating end-stage liver disease, fulminant hepatitis, and oncological malignancies and organ shortage is a major limiting factor worldwide. The use of grafts based on extended donor criteria have become internationally accepted. Oxygenated machine perfusion technologies are the most recent advances in organ transplantation; however, it is only applied after a period of cold ischemia. Due to its high cost, we aimed to use a novel device, OxyFlush®, based on oxygenation of the preservation solution, applied during liver procurement targeting the maintenance of ATP during static cold storage (SCS). Twenty patients were randomly assigned to the OxyFlush or control group based on a 1:1 ratio. In the OxyFlush group, the perfusion solution was oxygenated with OxyFlush® device while the control group received a non-oxygenated solution. Liver and the common bile duct (CBD) biopsies were obtained at three different time points. The first was at the beginning of the procedure, the second during organ preparation, and the third after total liver reperfusion. Biopsies were analyzed, and adenosine triphosphate (ATP) levels and histological scores of the liver parenchyma and CBD were assessed. Postoperative laboratory tests were performed. OxyFlush® was able to maintain ATP levels during SCS and improved the damage caused by the lack of oxygen in the CBD. However, OxyFlush® did not affect laboratory test results and histological findings of the parenchyma. We present a novel low-cost device that is feasible and could represent a valuable tool in organ preservation during SCS.

Wogonin Alleviates DCD Liver Ischemia/Reperfusion Injury by Regulating ALOX15/iNOS-mediated Ferroptosis.

Donation after circulatory death livers are more susceptible to ischemia/reperfusion injury (IRI) because of a longer period of warm ischemia. Growing evidence now suggests that ferroptosis plays a key regulatory role in the development of IRI, so targeting ferroptosis may be an effective strategy to alleviate IRI in liver transplantation (LT). Using donation after circulatory death LT models in rats and oxygen-glucose deprivation/reoxygenation (OGD/R) models in BRL-3A cells, we tested the effect of the Chinese medicine monomer wogonin on liver IRI and explored the specific mechanism. Wogonin attenuated liver IRI and increased the survival rate of rats by inhibiting lipid peroxidation and ferroptosis. Mechanistically, arachidonic acid 15-lipoxygenase-1 (ALOX15) and inducible nitric oxide synthase (iNOS) were identified as potential targets of baicalein through bioinformatics analysis combined with in vivo and in vitro experiments. This result was further confirmed by molecular docking and cellular thermal shift assays. Finally, we silenced ALOX15 and iNOS in the OGD/R cell model and found that silencing ALOX15 and iNOS could reproduce the regulatory effect of wogonin and abrogate the regulatory effect of wogonin. In brief, this study emphasizes that wogonin exerts a protective effect in liver IRI through the regulation of ALOX15- and iNOS-mediated ferroptosis. ALOX15 and iNOS are potential targets for intervention in IRI induced by LT, and wogonin is a drug candidate for LT patients.

Intraluminal oxygen can keep small bowel mucosa intact in a segmental ischemia model

Intestinal preservation for transplantation is accompanied by hypoperfusion with long periods of ischemia with total blood cessation and absolute withdrawal of oxygen leading to structural damage. The application of intraluminal oxygen has been successfully tested in small-animal series during storage and transport of the organ but have been so far clinically unrelatable. In this study, we tested whether a simple and clinically approachable method of intraluminal oxygen application could prevent ischemic damage in a large animal model, during warm ischemia time. We utilised a local no-flow ischemia model of the small intestine in pigs. A low-flow and high-pressure intraluminal oxygen deliverance system was applied in 6 pigs and 6 pigs served as a control group. Mucosal histopathology, hypoxia and barrier markers were evaluated after two hours of no-flow conditions, in both treatment and sham groups, and in healthy tissue. Macro- and microscopically, the luminal oxygen delivered treatment group showed preserved small bowel’s appearance, viability, and mucosal integrity. A gradual deterioration of histopathology and barrier markers and increase in hypoxia-inducible factor 1-α expression towards the sites most distant from the oxygen application was observed. Intraluminal low-flow, high oxygen delivery can preserve the intestinal mucosa during total ischemia of the small intestine. This finding can be incorporated in methods to overcome small bowel ischemia and improve intestinal preservation for transplantation.

Primary cilia as a targetable node between biliary injury, senescence and regeneration in liver transplantation

Biliary complications are a major cause of morbidity and mortality in liver transplantation. Up to 25% of patients that develop biliary complications require additional surgical procedures, re-transplantation or die in the absence of a suitable regraft. Here, we investigate the role of the primary cilium, a highly specialised sensory organelle, in biliary injury leading to post-transplant biliary complications. Human biopsies were used to study the structure and function of primary cilia in liver transplant recipients that develop biliary complications (n= 7) in comparison with recipients without biliary complications (n= 12). To study the biological effects of the primary cilia during transplantation, we generated murine models that recapitulate liver procurement and cold storage, and assessed the elimination of the primary cilia in biliary epithelial cells in the K19CreERTKif3afl/fl mouse model. To explore the molecular mechanisms responsible for the observed phenotypes we used invitro models of ischemia, cellular senescence and primary cilia ablation. Finally, we used pharmacological and genetic approaches to target cellular senescence and the primary cilia, both in mouse models and discarded human donor livers. Prolonged ischemic periods before transplantation result in ciliary shortening and cellular senescence, an irreversible cell cycle arrest that blocks regeneration. Our results indicate that primary cilia damage results in biliary injury and a loss of regenerative potential. Senescence negatively impacts primary cilia structure and triggers a negative feedback loop that further impairs regeneration. Finally, we explore how targeted interventions for cellular senescence and/or the stabilisation of the primary cilia improve biliary regeneration following ischemic injury. Primary cilia play an essential role in biliary regeneration and we demonstrate that senolytics and cilia-stabilising treatments provide a potential therapeutic opportunity to reduce the rate of biliary complications and improve clinical outcomes in liver transplantation. Up to 25% of liver transplants result in biliary complications, leading to additional surgery, retransplants, or death. We found that the incidence of biliary complications is increased by damage to the primary cilium, an antenna that protrudes from the cell and is key to regeneration. Here, we show that treatments that preserve the primary cilia during the transplant process provide a potential solution to reduce the rates of biliary complications.

Early cognitive dysfunction development immunological predictors in the ischemic stroke acute period

The purpose of the study is activity identification CXC family cytokines in patients with cognitive impairments in the acute period of ischemic stroke.Material and methods. 78 patients with diagnosis “Ischemic stroke” were examined. Depending on cognitive impairment (Montreal Cognitive Assessment (MoCA)) patients were divided into two groups: the 1st group — 58 patients with cognitive decline (MoCA ≤ 25 points); the 2nd group — 20 patients without cognitive decline. Neuropsychologic testing was performed on the second day of hospitalisation and included episodic memory, executive function, speech, gnosis, praxis and IQCODE parameters examination. Laboratory diagnosis consisted of level assessing of CXC family chemokines (CXCL10, CXCL11, CXCL9, CXCL1, CXCL8) and TNF-α cytokine in patients’ plasma on the second day of hospitalisation. Statistical analysis was employed using the Python programing language and its libraries Pandas and SciPy.Results. Statistical analysis revealed the highest level of IP-10/CXCL10 chemokines (p = 0.002) and Gro-a/CXCL1 (p = 0.044) in patients of the 1st group, statistically significant correlations of MoCA and IQCODE with IP-10/CXCL10 and Gro-a/CXCL1 concentrations, correlations of IP-10/CXCL10 concentrations with semantic information processing functions (r = –0.512), subject gnosis (r = –0.211), memory (r = 0.275), speech (r = –0.400), and Gro-a/ CXCL1 level with semantic information processing (r = –0.418).Conclusion. The study of chemokines of the CXC cluster represents a relevant and promising direction in the diagnosis and assessment of progression of early post-stroke cognitive impairment of mixed genesis due to minimal invasiveness and high specificity. Further studies are needed to verify CXCL chemokines, particularly IP-10/CXCL10 and Gro-a/CXCL1 as potential molecular markers of neurological damage in neurodegenerative and inflammatory diseases of the central nervous system.

#573 Development of a model for simultaneous normothermic perfusion in porcine kidney grafts

Abstract Background and Aims In recent years, DCD or ECD deceased donors have been increasingly used in kidney transplantation as a partial response to the deceased donor shortage, leading to a suboptimal quality of kidney grafts. There is a need for developing better kidney graft preservation methods, such as hypo- or normo- thermic machine perfusion. Machine perfusion might provide the unique opportunity to directly treat the perfused kidney grafts to improve their quality and to decrease ischemia/reperfusion injury during transplantation. Our aim was to develop a pig model of simultaneous normothermic perfusion of both kidneys procured from the same donor and to compare the assessment of renal function through the injection of creatinine and iohexol. Method Under general anaesthesia, the donor pigs (n = 5) were euthanized by exsanguination and the blood was recovered using a cell-saving system. Both kidneys (n = 10) were submitted to 30 min of warm and a 2-hour cold ischemia period, before being perfused for 6 hrs at 37°C. Kidney perfusion started and run in parallel using 2 independents, modified extracorporeal machines. Urine production, arterial blood gas exchange, and perfusion parameters (flow, pressure, resistance) were monitored and compared. Creatinine and iohexol were added to the perfusate of both machines to assess renal function. Results A parallel evolution of blood parameters in both perfusions was observed. By maintaining a constant perfusion pressure of 70 mmHg, flow rates increased to 100 mL/min. Despite variations in urinary excretion, creatinine and iohexol clearances remained comparable, demonstrating a parallel kidney function. Conclusion In conclusion, we established a model of parallel and simultaneous normothermic perfusion of pig kidneys, and for the first time, we demonstrated the utility of iohexol measurements for improved functional assessment in an isolated perfusion model. After randomization of the grafts, this model will be used for testing innovative therapies as MSC during perfusion, both in swine kidneys and human discarded grafts, using the contralateral kidney as a paired control.

Assessment of temporal changes in glomerular filtration rate following clamp ischemia in male and female rats using transcutaneous FITC-sinistrin clearance

Warm arterial clamping with reperfusion in rats is a commonly utilized model of ischemic kidney injury (IRI). Traditionally, changes in plasma creatinine or creatinine clearance have been utilized to assess kidney function in this model. A limitation of these approaches, however, is that changes in plasma creatinine are relatively slow to occur, resulting in low temporal fidelity. This limits our ability to relate changes in kidney function to histo-pathological changes observed during reperfusion of the kidneys. Transcutaneous assessment of FITC-sinistrin clearance enables accurate, repeated measurement of glomerular filtration rate in conscious animals over short segments of time (hours) without drawing blood. The goal of the current study was to characterize temporal changes in renal function in male and female rats after reperfusion from bi-lateral warm arterial clamp ischemia using transcutaneous FITC-sinistrin clearance. Our study was performed in age matched male (n=8) and female (n=5) Sprague Dawley rats (12-20wks of age). FITC sinistrin clearance was measured by affxing a miniaturized transcutaneous measurement device between the shoulder blades (MediBeacon) of rats. 50mg/kg of FITC-sinistrin was then injected i.v via the tail vein and the device allowed to record for ~3 hours. Measurements were taken either at pre-surgery (baseline), 1-3 hours, 24 hours or 7 days following reperfusion of the kidneys from warm bilateral arterial clamp ischemia. For the ischemic surgery, animals were anesthetized with isoflurane (2-5%, 95% O2) and the right and left kidneys were accessed by flank incisions. After being exposed, the renal arteries were separated from the renal veins via dissection. Both renal arteries were then clamped with microserrefines for 45 minutes. After the ischemic period, the clamps were removed, allowing blood flow to be restored to the kidneys. Body temperature was measured via a rectal probe and maintained at 37°C throughout the procedure by a servo-controlled heating table and UV heating lamp. The wounds were then closed, and the animals allowed to recover. Buprenorphine was administered as an analgesic. For each measurement, the ½ life of FITC sinistrin was determined using a 1-compartment model (MB Lab software) and glomerular filtration rate (GFR) per 100g of body weight rate calculated. Baseline GFR was 0.94±0.03ml/min/100g in males and 1.09±0.02/min/100g in females (PTTEST=0.04). Following 45 minutes of warm bilateral arterial ischemia and reperfusion, GFR fell to 0.24±0.08ml/min/100g in male and 0.36±0.15ml/min/100g in females within 1-3 hours of reperfusion. At 24 hours of reperfusion, GFR averaged 0.06±0.03ml/min/100g in males and 0.28±0.16ml/min/100g in females. GFR recovered in males and females by 7 days of reperfusion averaging 0.86±0.10ml/min/100g in males and 0.83±0.00ml/min/100g in females. There was no significant difference between FITC-sinistrin clearance between males and females at any time point after IRI. Our data indicate that most of the reduction in GFR is present immediately after releasing the clamp. This is consistent with continued vascular disturbances mediating the initial decline in glomerular filtration rate in this model (i.e. vasospasm). The absence of sex differences in GFR decline using this method suggests that sex-differences detected using plasma creatinine may be, at least in part, secondary to the more rapid production of creatinine in males than in females or greater baseline filtration/body weight ratio in females compared to males rather than differences in renal function decline to ischemia. American Heart Association Transformational Project Award 970585 to Paul O'Connor. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The Effect of 0.1 Hz Blood Flow Oscillations on Microvascular Blood Flow Responses Following Severe Ischemia

Background: We have shown that inducing 10 second (0.1 Hz) oscillations in arterial pressure and blood flow protects against reductions in tissue oxygenation during ischemia, independent of changes in macrovascular blood flow. However, it is unknown whether 0.1 Hz hemodynamic oscillations impacts microvascular function and vasodilatory capacity following severe ischemia. To examine this question, we assessed the reactive hyperemic response following a prolonged peripheral limb ischemia protocol with and without induced 0.1 Hz hemodynamic oscillations. Hypothesis: 0.1 Hz oscillations in blood pressure and blood flow will increase microvascular blood flow, assessed via reactive hyperemia following a 10-min period of ischemia. Methods: Thirteen healthy human participants (6M, 7F; 27.3 ± 4.2 y) completed two experimental protocols separated by ≥48 h. In both conditions, ischemia of the forearm was induced with a pneumatic cuff on the upper arm to decrease brachial artery blood velocity by ~70-80% from baseline. In the oscillation condition (OSC), 0.1 Hz oscillations in mean arterial pressure (MAP) and brachial artery blood flow were induced by inflating and deflating bilateral thigh cuffs every 5-s (10-s cycles; 0.1 Hz) throughout the forearm ischemia period. In the control condition (CON), the thigh cuffs were in place, but were inactive throughout the forearm ischemia period. Beat to beat arterial pressure was measured via finger photo plethysmography, and brachial artery diameter and blood velocity were measured via duplex Doppler ultrasound during baseline, ischemia, and the reperfusion period. The maximum mean brachial artery blood velocity, and 3-min area under the curve (AUC) of mean brachial artery blood velocity were used to determine the reactive hyperemia response. Results: The magnitude of forearm ischemia, indexed by the reduction in brachial artery conductance, was matched between conditions (CON: -74.8 ± 10.4% vs. OSC: -75.6 ± 6.7%, p=0.39). Reactive hyperemia was not different between conditions as indexed by maximum mean brachial artery blood velocity (CON: 36.4 ± 12.4 cm/s vs. OSC: 39.3 ± 11.2 cm/s, p=0.53) or 3-min brachial artery blood velocity AUC (CON: 1495 ± 744 (cm/s)2 vs. OSC: 1596 ± 804 (cm/s)2, p=0.74). Conclusion: Inducing 0.1 Hz hemodynamic oscillations during severe ischemia does not affect microvascular function, indexed by reactive hyperemia following release of the ischemic stimulus. A more direct measure of microvascular blood flow is needed to examine whether 0.1 Hz hemodynamic oscillations improves microvascular perfusion during ischemia. NIH Neurobiology of Aging & Alzheimer’s Disease Training Grant (T32 AG02049; KAD); American Heart Association Transformational Project Award (19TPA34910743; CAR); American Heart Association Predoctoral Fellowship (23PRE1018469; KAD); UNTHSC Physiology and Anatomy Seed Grant 2021 (CAR). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.