Ischemia-Reperfusion Injury: Influencing the Microcirculatory and Cellular Environment

Annexin-A5 monomer as a membrane repair agent for the treatment of renal ischemia-reperfusion injury

BACKGROUND

Renal ischemia-reperfusion injury (IRI) is one of the causes of acute kidney injury. Annexin A5 (AnxA5), a calcium-dependent cell membrane-binding protein, shows protective effects in various organ IRI models. This study explored the therapeutic effect of exogenous AnxA5 monomer protein on renal IRI and its potential mechanism of action.

METHODS AND RESULTS

Different doses of AnxA5 were injected intravenously to treat bilateral renal IRI in SD rats. This model confirmed the protective effects of AnxA5 on kidney structure and function. In vitro, HK-2 cells were subjected to hypoxia for 12 h, followed by restoration of normal oxygen supply to simulate IRI. In vitro experiments demonstrated the mechanism of action of AnxA5 by measuring cellular activity and permeability. A comparison of the mutant AnxA5 protein M23 and the application of a calcium-free culture medium further validated the protective effect of AnxA5 by forming a network structure.

CONCLUSIONS

Exogenous AnxA5 monomers prevented renal IRI by binding to the damaged renal tubular epithelial cell membrane, forming a two-dimensional network structure to maintain cell membrane integrity, and ultimately prevent cell death.

Efficacy of the shoelace technique for extremity fasciotomy wounds due to compartment syndrome

BACKGROUND

The shoelace technique for compartment syndrome allows application of sustained tightening tension to an entire wound and intermittent tightening of the shoelace without requiring its replacement or anesthesia. We retrospectively evaluated the usefulness of the shoelace technique in the management of extremity fasciotomy wounds before and after its introduction in our institution.

METHODS

We targeted 25 patients who were diagnosed as having compartment syndrome and underwent extremity fasciotomy at our hospital from April 2012 to December 2021. The N group, comprising 12 patients treated without the shoelace technique, and the S group, comprising 13 patients treated with the shoelace technique, were compared retrospectively for each outcome.

RESULTS

There were no significant differences between the two groups in patient background. Compared with the N group patients, all of the S group patients avoided skin grafting (S group: n = 0, 0%; N group: n = 6, 50.0%; p < 0.01). However, there was no significant difference in the number of days to final wound closure (S group: 39.5 [IQR 24.3-58.0] days; N group: 24.0 [IQR 18.5-31.0] days, p = 0.06).

CONCLUSIONS

We considered the shoelace technique to be a useful wound closure method for fasciotomy wounds caused by compartment syndrome because it can significantly reduce the need for skin grafting and tends to shorten the wound closure period.

Comparison of Prognostic Performance between Procalcitonin and Procalcitonin-to-Albumin Ratio in Post Cardiac Arrest Syndrome

(1) Background: Post-cardiac arrest syndrome (PCAS) is a type of global ischemic reperfusion injury that occurs after the return of spontaneous circulation (ROSC). The procalcitonin to albumin ratio (PAR) has been studied as an independent prognostic factor of various diseases. There are no previous studies of PAR in patients with PCAS. We assessed if PAR is more effective than procalcitonin (PCT) in predicting prognosis for patients with PCAS. (2) Methods: This retrospective cohort study included a total of 187 patients with PCAS after non-traumatic out-of-hospital cardiac arrest (OHCA) between January 2016 and December 2020. Multivariate logistic regression analysis was conducted to assess the association between PAR and PCAS prognosis. The predictive performance of PAR was compared with PCT via the receiver-operating characteristic (ROC) analysis and DeLong test.; (3) Results: PAR at 24 and 48 h after hospital admission were independently associated with one-month neurological outcome (OR: 1.167, 95% CI: 1.023-1.330; OR: 1.077, 95% CI: 1.012-1.146, p < 0.05). By ROC analysis, PAR showed better performance over PCT at 48 h after admission in predicting one-month CPC (0.763 vs. 0.772, p = 0.010). (4) Conclusions: Our findings suggest that PAR at 48 h after admission is more effective in predicting a one-month neurological outcome than PCT at 48 h after admission in patients with PCAS after OHCA.

Narrative review of systemic inflammatory response mechanisms in cardiac surgery and immunomodulatory role of anesthetic agents

Although surgical techniques and perioperative care have made significant advances, perioperative mortality in cardiac surgery remains relatively high. Single- or multiple-organ failure remains the leading cause of postoperative mortality. Systemic inflammatory response syndrome (SIRS) is a common trigger for organ injury or dysfunction in surgical patients. Cardiac surgery involves major surgical dissection, the use of cardiopulmonary bypass (CPB), and frequent blood transfusions. Ischemia-reperfusion injury and contact activation from CPB are among the major triggers for SIRS. Blood transfusion can also induce proinflammatory responses. Here, we review the immunological mechanisms of organ injury and the role of anesthetic regimens in cardiac surgery.

Heart Disease and Ageing: The Roles of Senescence, Mitochondria, and Telomerase in Cardiovascular Disease

During ageing molecular damage leads to the accumulation of several hallmarks of ageing including mitochondrial dysfunction, cellular senescence, genetic instability and chronic inflammation, which contribute to the development and progression of ageing-associated diseases including cardiovascular disease. Consequently, understanding how these hallmarks of biological ageing interact with the cardiovascular system and each other is fundamental to the pursuit of improving cardiovascular health globally. This review provides an overview of our current understanding of how candidate hallmarks contribute to cardiovascular diseases such as atherosclerosis, coronary artery disease and subsequent myocardial infarction, and age-related heart failure. Further, we consider the evidence that, even in the absence of chronological age, acute cellular stress leading to accelerated biological ageing expedites cardiovascular dysfunction and impacts on cardiovascular health. Finally, we consider the opportunities that modulating hallmarks of ageing offer for the development of novel cardiovascular therapeutics.

Chuanzhitongluo capsule ameliorates microcirculatory dysfunction in rats: Efficacy evaluation and metabolic profiles

Background: Ischemic stroke is a leading cause of mortality and disability worldwide. Microcirculatory dysfunction is the foremost hindrance for a good clinical prognosis in ischemic stroke patients. Clinical researches show that Chuanzhitongluo capsule (CZTL) has a curative effect during the recovery period of ischemic stroke, which contributes to a good prognosis. However, it is not known whether CZTL treats ischemic stroke by ameliorating microcirculation dysfunction.

Objective: In this study, we investigated the influence of CZTL on microcirculation and its underlying mechanism.

Methods: A rat model of acute microcirculatory dysfunction was established by stimuli of adrenaline and ice water. The microcirculatory damage in model rats and the efficacy of CZTL were assessed by detecting laser speckle contrast imaging, coagulation function, hemorheology, vasomotor factor and microcirculation function. The potential mechanism of CZTL action was explored by the untargeted metabolomic analysis based on ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry.

Results: Laser speckle contrast imaging showed that model rats suffered low perfusion in ears, feet and tails, and CZTL treatment increased microcirculatory blood flow. Coagulation function detection results showed that CZTL diminished the reduction of thrombin time, prothrombin time, activated partial thromboplastin time and the elevated fibrinogen level caused by acute microcirculatory dysfunction. Furthermore, CZTL could recover the increased blood viscosity as well as the abnormal vasomotor and microcirculation function in rats with acute microcirculatory dysfunction. Metabolomics analysis indicated that CZTL might regulate sphingolipid metabolism and arachidonic acid metabolism to exert protective effects on microcirculation.

Conclusion: These results elucidated that CZTL was highly effective against microcirculatory dysfunction and its potential mechanisms related with the modulation of sphingolipid and arachidonic acid metabolic pathways. The present study provided a new perspective on the clinical application of CZTL, and it contribute to explore novel therapeutic drug against microcirculatory dysfunction.

Catalpol Enhances Random-Pattern Skin Flap Survival by Activating SIRT1-Mediated Enhancement of Autophagy

Random-pattern skin flap necrosis limits its application in the clinic. It is still a challenge for plastic surgeons. Catalpol is an effective ingredient extracted from Rehmannia glutinosa, which is reported to promote angiogenesis and protect against ischemic cerebral disease. The aim of our experiment is to assess whether catalpol can facilitate random flap survival and the underlying mechanisms. Male “McFarlane flap” rat models were employed to explore the protective effects of catalpol. The range of necrosis in the flap was calculated 7 days after the models were established. The flap specimens were harvested for further experiments, including angiogenesis, apoptosis, oxidative stress, and autophagy evaluation. Catalpol-treated group promoted the average survival area of the flap than that in the control group. Based on immunohistochemical staining, Western blotting, and ROS detection, we found that catalpol significantly reduces oxidative stress and apoptosis and increases angiogenesis. Hematoxylin and eosin (H&E) staining and laser Doppler images further clarified the enhancement of angiogenesis after catalpol treatment. The impact of catalpol in flap was switched by using 3-methyladenine (3MA), proving the important role of autophagy in curative effect of catalpol on skin flaps. Importantly, the ability of catalpol to regulate autophagy is mediated by the activation of sirtuin 1 (SIRT1) based on its high affinity for SIRT1. Our findings revealed that catalpol improved the viability of random skin flaps by activating SIRT1-mediated autophagy pathway.

Hydrogen-generating Si-based agent protects against skin flap ischemia-reperfusion injury in rats

Hydrogen is effective against ischemia–reperfusion (I/R) injury in skin flaps. However, the difficulty of continuously administering a sufficient amount of hydrogen using conventional methods has been an issue in the clinical application of hydrogen-based therapy. An Si-based agent administered orally was previously shown to continuously generate a large amount of hydrogen in the intestinal environment. In this study, we assessed the effect of the Si-based agent on the inhibition of I/R injury in skin flaps using a rat model. In the I/R groups, the vascular pedicle of the abdominal skin flap was occluded for three hours followed by reperfusion. In the I/R + Si group, the Si-based agent was administered perioperatively. After reperfusion, flap survival rate, blood flow, oxidative stress markers, inflammatory markers/findings, and degree of apoptosis were evaluated. Flap survival rate was significantly higher, and histological inflammation, apoptotic cells, oxidative stress markers, and levels of inflammatory cytokine mRNA and protein expression were significantly lower, in the I/R + Si group compared to the I/R group. The Si-based agent suppressed oxidative stress, apoptosis, and inflammatory reactions resulting from I/R injury, thereby contributing to improvements in skin flap survival.

Establishment of a Modified and Standardized Ferric Chloride-Induced Rat Carotid Artery Thrombosis Model

BACKGROUND

Ferric chloride is widely utilized in inducing thrombosis in small vessels of experimental animals. However, the lack of its application in large blood vessels of experimental animals and inconsistent concentration has limited its application. Therefore, we systematically tested the most suitable concentration and reliable induction time in the experiment of using ferric chloride to induce rat carotid artery thrombosis.

METHODS

In this study, we selected the common carotid artery of 59 Sprague-Dawley rats as the target vessel. The exploration process was divided into three stages. First, to determine the optimum induction concentration, we compared the effects of 30-60% ferric chloride on thrombus formation within 24 h. Second, to confirm the handling time, we tested different induction times from 3 min to 10 min. Lastly, we used the thrombolytic drug rt-PA to detect whether the formed thrombus can be lysed. Doppler blood flow imaging and H-E staining were employed to estimate the blood flow and thrombus. The ATP levels in the brain were measured using a bioluminescence ATP assay kit.

RESULTS

We found that the application of 50% ferric chloride for 10 min was enough to successfully induce thrombosis in the rat carotid artery and without spontaneous thrombolysis after 24 h. It is better than other concentrations and will lead to the decline of the ATP content in the ischemic hemisphere.

CONCLUSIONS

Our results indicate that the rat carotid artery thrombosis model induced by 50% ferric chloride for 10 min is stable and reliable.

Bisphosphonate of Zoledronate Has Antiapoptotic Effect on Hypoxia/Reoxygenation Injury in Human Embryonic Stem Cell-Derived Cardiomyocytes Through Trk Signaling Pathway

In this work, we investigated the in vitro and in vivo functions of bisphosphonate of zoledronate (Zd) in hypoxia/reoxygenation (H/R) injured human embryonic stem cell-derived cardiomyocytes (hES-CMs). In the in vitro setting, the effects of Zd on hES-CM survival and differentiation were examined. We found that low and medium concentrations (<2 µm) of Zd did not induce cell death of hES-CMs. 0.5 µm Zd protected H/R-induced hES-CM apoptosis but did not affect key differentiation proteins, including hcTnl, PECM-1 Cnx43 and Pan-Cadherin. In addition, Zd-induced TrkA/B phosphorylation and promoted VEGF to counter the apoptotic effect of H/R injury. In the in vivo animal model of myocardial infarction, Zd treatment promoted the survival of hES-CMs by inducing PECAM1 and hcTnl. Thus, we concluded that Zd protected H/R-induced hES-CM apoptosis in vitro and promoted hES-CM survival in vivo. These data may facilitate the development of human embryonic stem cells into clinical applications for patients with ischemic heart disease.

Evaluation of Hyperspectral Imaging for Follow-Up Assessment after Revascularization in Peripheral Artery Disease

Background: Assessment of tissue oxygenation is an important aspect of detection and monitoring of patients with peripheral artery disease (PAD). Hyperspectral imaging (HSI) is a non-contact technology for assessing microcirculatory function by quantifying tissue oxygen saturation (StO₂). This study investigated whether HSI can be used to monitor skin oxygenation in patients with PAD after appropriate treatment of the lower extremities. Methods: For this purpose, 37 patients with PAD were studied by means of ankle–brachial index (ABI) and HSI before and after surgical or endovascular therapy. Thereby, the oxygenation parameter StO₂ and near infrared (NIR) perfusion index were quantified in seven angiosomes on the diseased lower leg and foot. In addition, the effects of skin temperature and physical activity on StO₂ and the NIR perfusion index and the respective inter-operator variability of these parameters were investigated in 25 healthy volunteers. Results: In all patients, the ABI significantly increased after surgical and endovascular therapy. In parallel, HSI revealed significant changes in both StO₂ and NIR perfusion index in almost all studied angiosomes depending on the performed treatment. The increase in tissue oxygenation saturation was especially pronounced after surgical treatment. Neither heat nor cold, nor physical activity, nor repeated assessments of HSI parameters by independent investigators significantly affected the results on StO₂ and the NIR perfusion index. Conclusions: Tissue oxygen saturation data obtained with HSI are robust to external confounders, such as temperature and physical activity, and do not show inter-operator variability; therefore, can be used as an additional technique to established methods, such as the ABI, to monitor peripheral perfusion in patients with PAD.

Morin Attenuated Cerebral Ischemia/Reperfusion Injury Through Promoting Angiogenesis Mediated by Angiopoietin-1-Tie-2 Axis and Wnt/β-Catenin Pathway

Cerebral damage following cerebral ischemia/reperfusion injury affects the neurological deficits and motor impairment of stroke patients in the long-term period. Angiogenesis, the essential process for restoration of cerebral blood flow (CBF) in the ischemic brain, promotes the recovery of neurological function following ischemia. The aim of this study was to investigate the long-term effects of morin on angiogenesis and functional outcomes in a middle cerebral artery occlusion (MCAO) and reperfusion model. Male Wistar rats were subjected to MCAO, and they were administered 30 mg/kg of morin at reperfusion via i.p. injection daily for 14 days. Fourteen days after I/R injury, the rats were evaluated for the brain damage, and angiogenic factors involved in Ang1/Tie-2 and Wnt/β-catenin signaling. In addition, at 1, 7, and 14 days after reperfusion, rotarod and pole tests were performed to investigate the functional recovery. We found morin significantly reduced the infarct size, blood-brain barrier (BBB) leakage, and apoptotic cells at 14 days after I/R injury. It also promoted angiogenesis via boosting the expression of angiogenic proteins, such as angiopoietin 1 (Ang1), Tie-2, Wnt3α, β-catenin, and cyclin D1. Morin-mediated angiogenesis was confirmed by a significant increase in microvessel's density in the penumbra area and an increase in von Willebrand factor (vWF) protein expression of the morin-treated rats. Moreover, the rotarod and pole tests also demonstrated morin increased functional recovery in the morin-treated rats compared to the vehicle rats. Therefore, our data exposed that morin promotes angiogenesis and improves functional outcomes in MCAO and reperfusion rats.

c-myc protects mice from ischemia stroke through elevating microRNA-200b-5p-regulated SIRT1 expression

OBJECTIVE

c-myc has been reported to attenuate ischemia stroke (IS). We initiated the research to uncover the molecular mechanism of c-myc with regard to microRNA (miR)-200b-5p/Sirtuin1 (SIRT1) axis.

METHODS

An IS mouse model was prepared by middle cerebral artery occlusion (MCAO). Measurements of c-myc, miR-200b-5p and SIRT1 levels in MCAO mice were conducted. c-myc, miR-200b-5p and SIRT1 expression levels in MCAO mice were detected. The neurological function, production of inflammatory cytokines, neuronal apoptosis, brain tissue pathology and neuronal survival of MCAO mice were observed.

RESULTS

c-myc and SIRT1 levels went downward while miR-200b-5p expression went upward in MCAO mice. Elevation of c-myc or suppression of miR-200b-5p improved neurological function, reduced inflammation and neuronal apoptosis, and attenuated brain tissue pathology and neuronal survival of MCAO mice. Enhancement of miR-200b-5p or knockdown of SIRT1 weakened c-myc-induced protection against MCAO-induced brain injury in mice.

CONCLUSION

Overall, c-myc protects mice from IS through elevating miR-200b-5p-targeted SIRT1 expression.

Senescence and senolytics in cardiovascular disease: Promise and potential pitfalls

Ageing is the biggest risk factor for impaired cardiovascular health, with cardiovascular disease being the cause of death in 40 % of individuals over 65 years old. Ageing is associated with an increased prevalence of atherosclerosis, coronary artery stenosis and subsequent myocardial infarction, thoracic aortic aneurysm, valvular heart disease and heart failure. An accumulation of senescence and increased inflammation, caused by the senescence-associated secretory phenotype, have been implicated in the aetiology and progression of these age-associated diseases. Recently it has been demonstrated that compounds targeting components of anti-apoptotic pathways expressed by senescent cells can preferentially induce senescence cells to apoptosis and have been termed senolytics. In this review, we discuss the evidence demonstrating that senescence contributes to cardiovascular disease, with a particular focus on studies that indicate the promise of senotherapy. Based on these data we suggest novel indications for senolytics as a treatment of cardiovascular diseases which have yet to be studied in the context of senotherapy. Finally, while the potential benefits are encouraging, several complications may result from senolytic treatment. We, therefore, consider these challenges in the context of the cardiovascular system.

Prognostic value of C-reactive protein to albumin ratio in patients resuscitated from out-of-hospital cardiac arrest

BACKGROUND

Despite major advances in basic and advanced life supports, patients who survived from out-of-hospital cardiac arrest (OHCA) have still poor prognosis. Several inflammatory parameters have been used to determine early and long-term prognosis in patients with OHCA. C-reactive protein-to-albumin ratio (CAR) is also a novel marker of systemic inflammation. To our knowledge, there is no study evaluating the clinical importance of CAR in OHCA patients.

AIMS

To evaluate the effect of CAR on in-hospital mortality in patients with OHCA.

METHODS

A total of 102 patients with OHCA were included in this study. The study population was divided into two groups as survivour (n = 43) and non-survivour (n = 59) during follow-up. Complete blood cell counts, biochemical and blood gas analyses were recorded for all patients. Neutrophil to lymphocyte ratio (NLR) was calculated as the ratio of neutrophil to lymphocyte. CAR was calculated as the ratio of C-reactive protein to the albumin.

RESULTS

NLR (P = .012), CAR (P < .001) and serum lactate level (P = .002) were significantly higher whereas lymphocyte (P = .008) and serum albumin (P < .001) were significantly lower in the non-survivour group compared with the survivour group. Multivariate logistic regression analysis showed that NLR (odds ratio [OR]: 1.044, 95% confidence interval [CI]: 1.044-1.437, P = .013), CAR (OR: 1.971, 95% CI: 1.327-2.930, P = .001) and lactate level (OR: 1.268, 95% CI: 1.095-1.469, P = .002) were independent predictors of in-hospital mortality.

CONCLUSIONS

We have demonstrated for the first time that CAR was an independent predictor of in-hospital mortality in OHCA patients.

Exenatide improves random-pattern skin flap survival via TFE3 mediated autophagy augment

Random-pattern skin flaps are widely applied to rebuild and restore soft-tissue damage in reconstructive surgery; however, ischemia and subsequent ischemia-reperfusion injury lead to flap necrosis and are major complications. Exenatide, a glucagon-like peptide-1 analog, exerts therapeutic benefits for diabetic wounds, cardiac injury, and nonalcoholic fatty liver disease. Furthermore, Exenatide is a known activator of autophagy, which is a complex process of subcellular degradation that may enhance the viability of random skin flaps. In this study, we explored whether exenatide can improve skin flap survival. Our results showed that exenatide augments autophagy, increases flap viability, enhances angiogenesis, reduces oxidative stress, and alleviates pyroptosis. Coadministration of exenatide with 3-methyladenine and chloroquine, potent inhibitors of autophagy, reversed the beneficial effects, suggesting that the therapeutic benefits of exenatide for skin flaps are due largely to autophagy activation. Mechanistically, we identified that exenatide enhanced activation and nuclear translocation of TFE3, which leads to autophagy activation. Furthermore, we found that exenatide activates the AMPK-SKP2-CARM1 and AMPK-mTOR signaling pathways, which likely lead to exenatide's effects on activating TFE3. Overall, our findings suggest that exenatide may be a potent therapy to prevent flap necrosis, and we also reveal novel mechanistic insight into exenatide's effect on flap survival.

Long Noncoding RNAs in Myocardial Ischemia-Reperfusion Injury

Following an acute myocardial infarction, reperfusion therapy is currently the most effective way to save the ischemic myocardium; however, restoring blood flow may lead to a myocardial ischemia-reperfusion injury (MIRI). Recent studies have confirmed that long-chain noncoding RNAs (LncRNAs) play important roles in the pathophysiology of MIRIs. These LncRNA-mediated roles include cardiomyocyte apoptosis, autophagy, necrosis, oxidative stress, inflammation, mitochondrial dysfunction, and calcium overload, which are regulated through the expression of target genes. Thus, LncRNAs may be used as clinical diagnostic markers and therapeutic targets to treat or prevent MIRI. This review evaluates the research on LncRNAs involved in MIRIs and provides new ideas for preventing and treating this type of injury.

Apigenin enhances viability of random skin flaps by activating autophagy

Random skin flap is widely used in plastic surgery. However, flap necrosis caused by ischemia-reperfusion injury limits its clinical applications. Apigenin, a naturally occurring flavonoid mainly derived from plants, facilitates flap survival. In this study, we explored the effects of apigenin on flap survival and the underlying mechanisms. A total of 54 mice having a dorsal random flap model were randomly divided into control, apigenin, and apigenin +3-methyladenine groups. These groups were treated with dimethyl sulfoxide solution, apigenin, and apigenin +3-methyladenine, respectively. The animals were then euthanized to assess angiogenesis, apoptosis, oxidative stress, and autophagy levels through histological and protein analyses. Apigenin promotes survival of the skin flap area and reduces tissue edema. In addition, apigenin enhanced angiogenesis, attenuated apoptosis, alleviated oxidative stress, and activated autophagy. Interestingly, 3-methyladenine reversed the effects of apigenin on flap survival, angiogenesis, apoptosis, and oxidative stress through inhibition of autophagy. The findings of this study show that apigenin promotes angiogenesis, inhibits cell apoptosis, and lowers oxidative stress by mediating autophagy, thus the improving survival rate of random skin flaps.

Shoelace Technique Plus Negative-Pressure Wound Therapy Closure in Fasciotomy Wounds

BACKGROUND

Fasciotomy incision closure is often performed with skin grafts that can lead to cosmetic and functional complications after surgical intervention. Because fasciotomy incisions do not result in skin loss, the authors hypothesized that better closure can be achieved by reducing tissue edema with negative-pressure wound therapy (NPWT) and reducing stress on the skin with the shoelace surgical technique.

METHODS

This 1-year prospective study included eight patients with acute compartment syndrome after extremity fractures and/or blunt injuries. Patients were treated with fasciotomies closed with the shoelace technique and NPWT for wound margin approximation. The NPWT device was changed every second day; the shoelace traction tension was tightened at the same time.

MAIN RESULTS

The mean time from fasciotomy to wound closure was 11.8 days (range, 5-30 days). There was no need for a skin graft or flap in any patient.

CONCLUSIONS

The shoelace technique plus NPWT may be successful in closing skin fasciotomies after acute compartment syndrome without causing additional morbidity.

Increase of major complications with a longer ischemia time in breast reconstruction with a free deep inferior epigastric perforator (DIEP) flap

Background

The deep inferior epigastric artery perforator (DIEP) flap is one of the most used free flaps for postmastectomy breast reconstruction. Prolonged ischemia can result in (partial) flap loss. The aim of this study was to evaluate the association between ischemia time and postoperative complications of DIEP flap breast reconstruction.

Methods

A retrospective study of all patients who received a breast reconstructionwith aDIEP flap atMaastricht University Medical Center in theNetherlands, between January 2010 and June 2017 (n = 677). The flaps were divided into two groups: flaps with an ischemia time less than 60 min and those with 60 min or more. Recipient site complications, in particular major complications equal to re-exploration, and partial or total flap loss were the primary outcome measures.

Results

In 23.9% of the 677 included DIEP flaps, the ischemia time was 60 min or longer. Within this group, a complication of the recipient site occurred in 30.9% of the flaps. A major complication occurred in 17.3% of the flaps with 60 min or more ischemia time.With regard to the flaps with less than 60-min ischemia time, a complication occurred in 22.1% of the cases of which 8.9%would be considered amajor complication. A significant association was found between ischemia time and major complications on univariate (p value = 0.003) and multivariate analyses (p value = 0.016).

Conclusions

This study demonstrates that an ischemia time less than 60 min is associated with a significantly lower risk of major recipient site complications compared to an ischemia time of 60 min or more.

Level of evidence: Level III, therapeutic, risk/prognostic study.

Establishment of Murine Model of Kidney Failure Induced by Severe Ischemia-Reperfusion Injury Useful to Evaluate Transplantation and Regenerative Therapies

BACKGROUND

Severe ischemia-reperfusion injury (SIRI) seems to be the key factor that can significantly affect the function of both native kidneys and renal allografts. Therefore, the development of a successful strategy is of a paramount importance in both basic and clinical research.

METHODS

To determine the effects of SIRI on the native kidney function, a murine model was planned as follows: group 1 (n = 6) mice underwent to nephrectomy plus ischemia-reperfusion injury for 30 minutes; group 2 (n = 6) mice underwent to nephrectomy without ischemia-reperfusion injury and thus served as sham controls for SIRI. The results of serum creatinine (SCr) were analyzed using Mann-Whitney U tests to calculate the significance between mean values. Survival between groups was measured by Kaplan-Meier test.

RESULTS

To reliably achieve an elevation of SCr levels animals were exposed to a SIRI. The values of SCr increased from 0.35 (SD, 0.09) mg/dL to about 2-fold within 2 days and 3-fold within the following 5 days. Under these given conditions the mice displayed signs and histologic findings of severe kidney damage. The survival rate was about 83% of the animals within a week, and they showed no capacity of complete spontaneous self-regeneration.

CONCLUSIONS

In this study, we aim to establish a murine model with extensive structural kidney damage and significant elevation of SCr levels, which could be used in basic and translational research of transplantation and regenerative therapies.

Dihydrocapsaicin-induced angiogenesis and improved functional recovery after cerebral ischemia and reperfusion in a rat model

This study investigated the long-term effects of dihydrocapsaicin (DHC)-induced angiogenesis and improved functional outcomes in cerebral ischemia and reperfusion (I/R) rats. Middle cerebral artery occlusion was induced in I/R rats for 2 h, followed by reperfusion. The animals were divided into three groups: sham, I/R + vehicle, and I/R + DHC (10 mg/kg body weight). Fourteen days after I/R injury, the DHC-treated I/R rats had decreased neurological deficit scores, infarct volume, and brain morphology changes. DHC-induced angiogenesis significantly increased the expression of angiogenic factor proteins, such as hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), and matrix metalloprotease 9 (MMP-9), at 3 d and 14 d following I/R and also increased the expression of angiogenic inhibitors, such as angiopoietin 1 (Ang-1) and its receptor tyrosine kinase (Tie-2), at 14 d following reperfusion. DHC-mediated angiogenesis was confirmed by a significant increase in positive BrdU labeling that co-localized with the von Willebrand factor (an endothelial cell marker) at 14 d after I/R. Furthermore, rotarod and pole tests demonstrated that DHC promoted functional recovery when compared with the vehicle group. Thus, the results reveal that DHC mediates angiogenesis and functional recovery after an ischemic stroke.

Human monocytes subjected to ischaemia/reperfusion inhibit angiogenesis and wound healing in vitro

OBJECTIVES

The sequence of initial tissue ischaemia and consecutive blood flow restoration leads to ischaemia/reperfusion (I/R) injury, which is typically characterized by a specific inflammatory response. Migrating monocytes seem to mediate the immune response in ischaemic tissues and influence detrimental as well as regenerative effects during I/R injury.

MATERIALS AND METHODS

To clarify the role of classical monocytes in I/R injury, isolated human monocytes were subjected to I/R in vitro (3 hours ischaemia followed by 24 hours of reperfusion). Cellular resilience, monocyte differentiation, cytokine secretion, as well as influence on endothelial tube formation, migration and cell recovery were investigated.

RESULTS

We show that I/R supported an enhanced resilience of monocytes and induced intracellular phosphorylation of the prosurvival molecules Erk1/2 and Akt. FACS analysis showed no major alteration in monocyte subtype differentiation and surface marker expression under I/R. Further, our experiments revealed that I/R changes the cytokine secretion pattern, release of angiogenesis associated proteins and MMP-9 activity in supernatants of monocytes exposed to I/R. Supernatants from monocytes subjected to I/R attenuated endothelial tube formation as indicator for angiogenesis as well as endothelial cell migration and recovery.

CONCLUSION

In summary, monocytes showed no significant change in cellular integrity and monocyte subtype after I/R. Functionally, monocytes might have a rather detrimental influence during the initial phase of I/R, suppressing endothelial cell migration and neoangiogenesis.

Pyruvate Protects Against Intestinal Injury by Inhibiting the JAK/STAT Signaling Pathway in Rats With Hemorrhagic Shock

BACKGROUND

This study aimed to investigate the role of Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway in protection by peritoneal resuscitation (PR) using pyruvate-peritoneal dialysis solution (PY-PDS) against intestinal injury from hemorrhagic shock (HS) in rats.

MATERIALS AND METHODS

Sixty-four rats were assigned to eight groups: group SHAM; group intravenous resuscitation (VR); groups NS, LA, and PY in which the rats were subjected to HS and PR with normal saline (NS), lactate-peritoneal dialysis solution (LA-PDS), and PY-PDS, respectively, combined with VR; and groups DMSO, RPM, and AG490 in which the rats were subjected to HS and VR with pretreatment of dimethyl sulfoxide (DMSO), rapamycin (RPM), and tyrphostin B42 (AG490).

RESULTS

At 2 h after HS and resuscitation, the levels of diamine oxidase, 15-F_2t-isoprostane, thromboxane B₂, and endothelin-1, in the blood and the intestinal mucosal apoptotic index and caspase-3 were lower in groups PY, RPM, and AG490 than in groups VR, NS, LA, and DMSO. Group PY showed lower levels of malondialdehyde and myeloperoxidase and a higher level of superoxide dismutase than groups VR, NS, and LA. Phosphorylated JAK2 and phosphorylated STAT3 levels were lower in groups PY, RPM, AG490, and LA than in groups VR, NS, and DMSO.

CONCLUSIONS

The protection mechanism of PR with PY-PDS combined with VR was related to the inhibition of the JAK/STAT signaling pathway during HS and resuscitation. The process might include suppression of oxidative stress, reduction of neutrophil infiltration, regulation of microcirculation, and inhibition of apoptosis.

Postconditioning Protection Against Myocardiocyte Anoxia/Reoxygenation Injury From Penehyclidine Hydrochloride

BACKGROUND/AIMS

To investigate the postconditioning protective effect of penehyclidine hydrochloride (PHC) against anoxia/reoxygenation (A/R) injury in H9c2 cells along with the involved mechanism and timing effect.

METHODS

We divided H9c2 cells into 7 groups: control group, A/R group and PHC+A/R groups at 0 min, 5 mins, 10 mins, 20 mins, 30 mins, respectively (treated with 0.1 μm/L PHC at 0 min, 5 mins, 10 mins, 20 mins, 30 mins after the reoxygenation procedure began). Cell apoptosis, oxidative stress, intracellular Ca2+ concentration, mitochondrial membrane potential and mitochondrial permeability transition pore (MPTP) opening were explored. Bcl-2, Bax, Cyt C, caspase-3 and caspase-9 levels were measured.

RESULTS

A/R significantly increased both cell injury and cell apoptosis. PHC showed postconditioning protective effect by attenuating superoxide production, decreasing Ca2+ overload, restraining MPTP activities, restoring mitochondrial membrane potential, regulating cell apoptosis proteins and modulation of mitochondrial pathway. Earlier administration of PHC offered greater postconditioning protective effect.

CONCLUSION

H9c2 cells were protected by PHC from A/R injury regardless of timing of PHC administration (0 min, 5 mins, 10 mins, 20 mins, 30 mins). However, earlier administration of PHC resulted in better PHC postconditioning protection.

Betulinic Acid Enhances the Viability of Random-Pattern Skin Flaps by Activating Autophagy

Random-pattern skin flap replantation is commonly used to repair skin defects during plastic and reconstructive surgery. However, flap necrosis due to ischemia and ischemia-reperfusion injury limits clinical applications. Betulinic acid, a plant-derived pentacyclic triterpene, may facilitate flap survival. In the present study, the effects of betulinic acid on flap survival and the underlying mechanisms were assessed. Fifty-four mice with a dorsal random flap model were randomly divided into the control, betulinic acid group, and the betulinic acid + 3-methyladenine group. These groups were treated with dimethyl sulfoxide, betulinic acid, and betulinic acid plus 3-methyladenine, respectively. Flap tissues were acquired on postoperative day 7 to assess angiogenesis, apoptosis, oxidative stress, and autophagy. Betulinic acid promoted survival of the skin flap area, reduced tissue edema, and enhanced the number of microvessels. It also enhanced angiogenesis, attenuated apoptosis, alleviated oxidative stress, and activated autophagy. However, its effects on flap viability and angiogenesis, apoptosis, and oxidative stress were reversed by the autophagy inhibitor 3-methyladenine. Our findings reveal that betulinic acid improves survival of random-pattern skin flaps by promoting angiogenesis, dampening apoptosis, and alleviating oxidative stress, which mediates activation of autophagy.

Perfusion imaging with 320-slice spiral computed tomography and color-coded digital subtraction angiography for assessing acute skeletal muscle ischemia-reperfusion injury in a rabbit model

BACKGROUND

In recent years, skeletal muscle-related ischemia-reperfusion injury (IRI) has become more common. IRI can lead to severe limb injuries, multiple organ failure, and even death in some cases. However, there is still a lack of rapid and sensitive detection methods for IRI in skeletal muscle. This study aims to explore the value of computed tomography perfusion imaging (CTPI) and color-coded digital subtraction angiography (DSA) in assessing acute IRI of skeletal muscle in a rabbit model.

METHODS

Fifty New Zealand white rabbits were randomly assigned to the ischemia-reperfusion (IR) group (n = 40) or sham group (n = 10). After 3 h of surgically-induced hindlimb ischemia, the IR group underwent reperfusion and CTPI and color-coded DSA were taken to assess the skeletal muscle at 0, 6, 12, or 24 h post-reperfusion. The data from CTPI and DSA in the right and left hindlimbs, blood flow (AF-R/L), blood volume (BV-R/L), contrast clearance rate (C-R/L) and the maximum contrast enhancement values (peak-R/L) were obtained. Serum superoxide dismutase (SOD), creatine kinase (CK), lactic dehydrogenase (LDH) and malondialdehyde (MDA) were measured. The statistical correlation between the above parameters (CTPI, color-coded DSA, and biochemical markers) was analyzed.

RESULTS

The mean value of AF-R/L, BV-R/L, C-R/L and peak-R/L decreased linearly from 1.07 ± 0.08 to 0.75 ± 0.11, 1.03 ± 0.06 to 0.85 ± 0.14, 0.93 ± 0.15 to 0.71 ± 0.18, and 1.07 ± 0.01 to 0.47 ± 0.04, respectively. The correlation coefficients between AF-R/L and SOD, CK, LDH and MDA were 0.57, - 0.44, - 0.60, and - 0.62, respectively (p < 0.001). The correlation coefficients between Peak-R/L and SOD, CK, LDH, MDA were 0.59, 0.68, 0.71 and 0.66, respectively (p < 0.001). The correlation coefficient between AF-R/L and Peak-R/L was 0.70 (p < 0.001).

CONCLUSION

Both CTPI and color-coded DSA could dynamically assess skeletal muscle IRI in rabbits.

Platelets in Skin Autoimmune Diseases

Systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and small vessel vasculitis are three autoimmune diseases frequently manifested in the skin. They share common pathogenic features, including production of autoantibodies, loss of tolerance to self-antigens, tissue necrosis and fibrosis, vasculopathy and activation of the coagulation system. Platelets occupy a central part within the coagulation cascade and are well-recognized for their hemostatic role. However, recent cumulative evidence implicates their additional and multifaceted immunoregulatory functions. Platelets express immune receptors and they store growth factors, cytokines, and chemokines in their granules enabling a significant contribution to inflammation. A plethora of activating triggers such as damage associated molecular patterns (DAMPs) released from damaged endothelial cells, immune complexes, or complement effector molecules can mediate platelet activation. Activated platelets further foster an inflammatory environment and the crosstalk with the endothelium and leukocytes by the release of immunoactive molecules and microparticles. Further insight into the pathogenic implications of platelet activation will pave the way for new therapeutic strategies targeting autoimmune diseases. In this review, we discuss the inflammatory functions of platelets and their mechanistic contribution to the pathophysiology of SSc, ANCA associated small vessel vasculitis and other autoimmune diseases affecting the skin.

Effect of hydrogen sulphide on inflammatory factors of the mitochondria after limb ischaemia-reperfusion injury in rats

The goal of this study was to evaluate the effect of hydrogen sulphide on inflammatory factors and the energy metabolism of mitochondria after limb reperfusion injury in rats. Sixty Wistar rats were divided into three groups: the sham operated group, the control group (the ischaemia-reperfusion injury [IRI] + normal saline group), and the experimental group (the IRI + H₂ S group). An experimental rat model of limb IRI was established. Skeletal muscle samples were collected to observe the content of necrotic products (including myoglobin (MB), lysophosphatidylcholine (LPC), and lipid peroxidation (LPO)); blood samples were collected to observe changes in the contents of interleukin-1 (IL-1), Interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α); and the mitochondria of skeletal muscle cells were extracted for mitochondrial transmembrane potential measurement and adenosine triphosphate (ATP) content determination. The results underwent further statistical analysis. The contents of MB, LPC, and LPO in the limb skeletal muscle, liver, lung, and kidney tissues of rats in the control group were significantly increased (P < 0.05) after IRI, which was markedly attenuated by treatment with hydrogen sulphide (P < 0.05). Ischaemia/reperfusion of the lower extremities in rats triggered a significant increase in serum levels of IL-1, IL-6, and TNF-α, which was significantly inhibited by treatment with H₂ S during ischaemia/reperfusion. In addition, the inhibitory effect tended to be time-dependent. After limb ischaemia/reperfusion, the mitochondrial transmembrane potential of skeletal muscle cells in the control group decreased significantly (P < 0.05), while the potential energy of the mitochondrial membrane in the experimental group was significantly higher than that in the control group (P < 0.05). The content of ATP in mitochondria of skeletal muscle cells of ischaemia-reperfusion rats in the control group was significantly lower than that in the sham operated group (P < 0.05), while the content of ATP of mitochondria in the experimental group after H₂ S treatment was significantly higher than the control group (P < 0.05). Hydrogen sulphide can alleviate the injury of skeletal muscle and distal organs after limb ischaemia-reperfusion and reduce local inflammatory reaction, which is essential in alleviating mitochondrial transmembrane potential and energy metabolism disorder during reperfusion injury. The purpose of the study is to summarise the available information and provide theoretical support for the application of hydrogen sulphide in the treatment of limb IRI in skeletal muscle and distal organs.

Color-coded Digital Subtraction Angiography for Assessing Acute Skeletal Muscle Ischemia-Reperfusion Injury in a Rabbit Model

RATIONALE AND OBJECTIVES

This paper describes an ongoing investigation of imaging and characterization of ischemia-reperfusion (IR) and investigated the use of color-coded digital subtraction angiography (DSA) to assess reperfusion injury or potential injury.

METHODS

New Zealand white rabbits were subjected to right hindlimb ischemia (IR, n = 24) or sham operation (control, n = 6). After 3 hours, the IR rabbits underwent reperfusion and were assessed at 0, 6, 12, or 24 hours (n = 6 each). DSA of the bilateral vastus lateralis muscle of each animal was performed. The maximum contrast enhancement value of a consistent region of interest in the right and left hind limbs (peak enhancement-R/L) was determined. Associations between the relative ratio of the peak right limb to the peak left limb (peak-R/L) and the following blood indicators of IR injury were analyzed: lactic dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA), and superoxide dismutase (SOD).

RESULTS

Serum LDH, CK, and MDA values in each IR group were significantly higher than those of the control group and were positively associated with the IR interval, whereas SOD was significantly lower and negatively associated. The mean peak-R/L decreased linearly with the IR interval from 1.07 ± 0.01 in the control group, and 0.93 ± 0.06, 0.79 ± 0.05, 0.65 ± 0.04, and 0.47 ± 0.04 at 0, 6, 12, and 24 hours in the IR groups. The coefficients of correlation between the peak-R/L and LDH, CK, MDA, SOD serum levels were -0.885, -0.908, -0.541, and 0.832, respectively.

CONCLUSIONS

Color-coded DSA may be used for monitoring the dynamics of skeletal muscle IR injury.

Systemic lupus erythematosus and systemic sclerosis: All roads lead to platelets

Systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are two phenotypically distincts inflammatory systemic diseases. However, SLE and SSc share pathogenic features such as interferon signature, loss of tolerance against self-nuclear antigens and increased tissue damage such as fibrosis. Recently, platelets have emerged as a major actor in immunity including auto-immune diseases. Both SLE and SSc are characterized by strong platelet system activation, which is likely to be both the witness and culprit in their pathogenesis. Platelet activation pathways are multiple and sometimes redundant. They include immune complexes, Toll-like receptors activation, antiphospholipid antibodies and ischemia-reperfusion associated with Raynaud phenomenon. Once activated, platelet promote immune dysregulation by priming interferon production by immune cells, providing CD40L supporting B lymphocyte functions and providing a source of autoantigens. Platelets are actively implicated in SLE and SSc end-organ damage such as cardiovascular and renal disease and in the promotion of tissue fibrosis. Finally, after understanding the main pathogenic implications of platelet activation in both diseases, we discuss potential therapeutics targeting platelets.

Role of glycogen synthase kinase following myocardial infarction and ischemia-reperfusion

Glycogen synthase kinase-3 beta (GSK3β) is principally is a glycogen synthase phosphorylating enzyme that is well known for its role in muscle metabolism. GSK3β is a serine/threonine protein Kinase, which is responsible for several essential roles in mammalian cells. This enzyme is implicated in the pathophysiology of many conditions involved in homeostasis and cellular immigration. GSK3β is involved in several pathways leading to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Increasing evidence has shown the potential importance of GSK3β in ischemic heart disease and ischemia-reperfusion pathologies. Reperfusion injury may occur in tissues after prolonged ischemia following reperfusion. Reperfusion injury can be life threatening. Reperfusion injury occurs due to a change in ionic homeostasis, excess free radical production, mitochondrial damage and cell death. There are however clear, cardiac-protective signals; although the molecular pathophysiology is not clearly understood. In normal physiology, GSK3β has a critical role in the cytoprotective pathway. However, it`s controversial role in ischemia and ischemia-reperfusion is a topic of current interest. In this review, we have opted to focus on GSK3β interactions with mitochondria in ischemic heart disease and expand on the therapeutic interventions.

Tissue conservation for transplantation

Pathophysiological changes that occur during ischemia and subsequent reperfusion cause damage to tissues procured for transplantation and also affect long-term allograft function and survival. The proper preservation of organs before transplantation is a must to limit these injuries as much as possible. For decades, static cold storage has been the gold standard for organ preservation, with mechanical perfusion developing as a promising alternative only recently. The current literature points to the need of developing dedicated preservation protocols for every organ, which in combination with other interventions such as ischemic preconditioning and therapeutic additives offer the possibility of improving organ preservation and extending it to multiple times its current duration. This review strives to present an overview of the current body of knowledge with regard to the preservation of organs and tissues destined for transplantation.

Mortality in patients resuscitated from out-of-hospital cardiac arrest based on automated blood cell count and neutrophil lymphocyte ratio at admission

INTRODUCTION

The neutrophil lymphocyte ratio(NLR) is a marker of systemic inflammation. We hypothesized that admission NLR is related to mortality and that epinephrine application during resuscitation influences NLR in patients after successful resuscitation from out of hospital cardiac arrest (OHCA).

METHODS

This retrospective cohort study is based on a registry including all OHCA patients who had a presumed cardiac cause of cardiac arrest and achieved sustained ROSC prior to admission between 2005 and 2014. Patients were categorized into three groups according to the calculated NLR at admission (NLR <6, ≥6, and 'abnormal differential' indicating no differential blood cell count on patients report due to exceedance of machine predefined parameter limits). The primary outcome measure was long-term mortality after OHCA. Cox proportional hazards models were used for multivariable analysis.

RESULTS

Out of 2273 OHCA patients during the study period a total of 1188(52%) patients were eligible for analysis, of those 274(23%) were female and mean age was 64 (25-75 IQR:52-72). Compared to a NLR<6 (n=442), adjusted hazard ratio for long-term mortality was significantly higher in patients with a NLR≥6 (n=447; 1.52 (95%CI 1.03-2.24)) and in patients with abnormal differential (n=299; 3.16 (95%CI 2.02-4.97)). Epinephrine application during resuscitation did not explain the effect of NLR on mortality.

CONCLUSION

In this large retrospective cohort study of altogether >1000 OHCA patients, hospital admission NLR<6 compared to abnormal differential or NLR≥6 was associated with mortality independently from epinephrine application.

Kidney remote ischemic preconditioning as a novel strategy to explore the accurate protective mechanisms underlying remote ischemic preconditioning

INTRODUCTION

This study reports a novel strategy for investigating the key factors responsible for the protective effect of remote ischemic preconditioning (RIPC) against renal ischemia-reperfusion (IR) injury, which remains the leading cause of the acute kidney injury that increase the morbidity and mortality in patients with renal impairment.

METHODS

The renal blood flow of the right kidneys in kidney remote ischemic preconditioning (KRIPC) group was occluded for 20 min. After 48 h, the renal blood flow of the left kidneys of both KRIPC and IPC groups was occluded for 30 min, and mice were dissected after 7 days of the last surgery. Blood samples were analyzed by an animal blood counter. The levels of creatinine, urea nitrogen, lipid peroxidation, nitric oxide (NO), and high-density lipoproteins (HDLs) were estimated in the plasma of mice. Kidney slices were stained with 2% triphenyltetrazolium chloride (TTC) to estimate the renal infarction.

RESULTS

Unlike KRIPC group, data from IPC group revealed a massive reduction in neutrophils count, a significant increase in creatinine, urea nitrogen, and HDLs levels, and an increase in the renal infarction compared with control group.

CONCLUSION

This is the first study demonstrating KRIPC as a novel and applicable model with the goal of defining the accurate protective mechanisms underlying RIPC against IR injury.

Remifentanil functions in the adaptive protection of cardiac function following ischemia

The present study aimed to investigate the effects of remifentanil during adaptation followinsg myocardial ischemia, and its possible clinical applications. Remifentanil was used during the simulation of adaptation following ischemia, which was performed using a Langendorff heart perfusion system. A total of 75 rats were divided into five groups, and the coronary flow, cardiac output and the cardiac enzyme content in coronary effluent prior to ischemia and post-reperfusion were recorded. Electron microscopy was used to observe myocardial ultrastructure, and the volume of aortic and coronary effluent was also measured. The recovery of cardiac output upon reperfusion was significantly higher following remifentanil treatment (91%), as compared with the ischemic control group (78%; P<0.05). The coronary flow of the experimental group following reperfusion decreased by 4 ml/min compared with the control group not exposed to ischemia, whilst the coronary flow of the ischemic control group was reduced by 20-24 ml/min. Flameng scoring of the mitochondria demonstrated improved mitochondrial ultrastructure following remifentanil treatment (score, 1.25±0.31), as compared the ischemic control group (score, 3.14±0.17). Lactate dehydrogenase (LDH) levels in the remifentanil-treated group were significantly lower at 10 and 30 min post-reperfusion (15.3±7.1 and 10.2±6.8 U/l, respectively), as compared with the control group (29.7±8.3 and 20.6±6.8 U/l, respectively; P<0.05). The results of the present study suggested that the application of remifentanil following ischemia protected heart function via the opioid receptors by reducing myocardial enzyme release, and attenuating ischemia-induced changes to the myocardial cell and mitochondrial structure.

Small molecule antidepressant amitriptyline protects hypoxia/reoxygenation-induced cardiomyocyte apoptosis through TrkA signaling pathway

Hypoxia/reoxygenation (H/R) induced cardiomyocytes apoptosis is a major factor leading to cardiovascular diseases. In this study, we investigated the protective effect of small molecule antidepressant amitriptyline (AMP) in regulating H/R-induced apoptosis in neonatal mouse cardiomyocyte in culture. Cardiomyocytes of C57BL/6J mice were treated with H/R condition in vitro. Various concentration of AMP was added into culture 2h prior to H/R conditioning. Cardiomyocyte apoptosis was evaluated by TUNEL assay. AMP induced downstream signaling pathway proteins, including tropomyosin receptor kinase A receptor (TrkA), phosphor-TrkA (p-TrkA), protein kinase B (Akt) and phosphor-Akt (p-Akt) were probed by western blot. TrkA phosphorylation was then blocked by K252a to investigate whether TrkA was functionally involved in the protection of AMP in H/R-injured cardiomyocyte. We found that H/R condition induced significant cardiomyocyte death and apoptosis, whereas AMP pretreatment considerably rescued cardiomyocyte death and apoptosis. Western blot analysis showed AMP activated TrkA signaling pathway through the phosphorylation of TrkA/Akt proteins. We also found that application of K252a inhibited the phosphorylation of TrkA/Akt signaling pathway, and subsequently abolished the protective effect of AMP in H/R-induced apoptosis in cardiomyocyte. Thus, our study revealed that AMP, through the activation of TrkA/Akt signaling pathway, plays a protective role in regulating H/R-induced apoptosis in cardiomyocyte.

NLRP3 Inflammasome Involvement in the Organ Damage and Impaired Spermatogenesis Induced by Testicular Ischemia and Reperfusion in Mice

We investigated the role of the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome during testis ischemia and reperfusion injury (TI/R) in wild-type (WT) and NLRP3 knock-out (KO) mice. WT and KO mice underwent 1 hour testicular ischemia followed by 4 hours and 1 and 7 days of reperfusion or a sham TI/R. Furthermore, two groups of WT mice were treated at the beginning of reperfusion and up to 7 days with two inflammasome inhibitors, BAY 11-7082 (20 mg/kg i.p.) or Brilliant Blue G (45.5 mg/kg i.p.), or vehicle. Animals were killed with a pentobarbital sodium overdose at 4 hours and 1 and 7 days, and bilateral orchidectomies were performed. Biochemical and morphologic studies were carried out in all groups. TI/R in WT mice significantly increased caspase-1 and interleukin (IL)-1β mRNA after 4 hours and IL-18 mRNA at 1 day of reperfusion (P ≤ 0.05). There was also a significant increase in caspase-3 and terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling-positive cells, marked histologic damage, and altered spermatogenesis in WT mice in both testes after 1 and 7 days of reperfusion. KO TI/R mice, WT TI/R BAY 11-7082, and Brilliant Blue G treated mice showed a significant reduced IL-1β and IL-18 mRNA expression, blunted caspase-1 and -3 expression, minor histologic damages, low terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling activity, and preserved spermatogenesis. These data suggest that the activation of NLRP3 plays a key role in TI/R, and its inhibition might represent a therapeutic target for the management of patients with unilateral testicular torsion.

Dabigatran treatment: effects on infarct size and the no-reflow phenomenon in a model of acute myocardial ischemia/reperfusion

The no-reflow phenomenon occurs when an epicardial coronary artery is reopened following myocardial infarction, but portions of the intramural microvasculature fail to reperfuse. One potential mechanism for this is the presence of fibrin tactoids. In addition, some recent studies have suggested that dabigatran treatment may be associated with increased incidence of myocardial infarction. Our aim was to investigate the effect on myocardial infarct size and no-reflow in an acute model of ischemia/reperfusion. Anesthetized, open-chest rabbits were randomly assigned to receive dabigatran (Dab, 0.5 mg/kg bolus + infusion, 0.15 mg/kg/h, IV, n = 11) or vehicle (Veh, n = 11) 15 m before a 30-m coronary artery occlusion and during 2.5 h of the 3 h reperfusion procedure. At the end of the reperfusion period, infarct size (% risk zone) and no-reflow defect were measured. The ischemic risk zone (% of left ventricle) was similar in groups, 24 % in Dab and 25 % in Veh. Necrosis was neither reduced nor increased by Dab treatment; expressed as a percentage of the risk region, infarct size was 30 ± 4 % in Dab and 28 ± 5 % in Veh, p = 0.76. The extent of no-reflow was comparable, expressed either as a percent of the risk region (19 ± 3 %, Dab and 18 ± 3 %, Veh) or as a percent of the necrotic zone (67 ± 8 % Dab and 65 ± 10 % Veh). Dab treatment had no effect on heart rate or blood pressure. Dabigatran treatment did not prevent or ameliorate the no-reflow phenomenon, suggesting that fibrin does not play a major role in the development of microvascular obstruction. Dabigatran did not exacerbate myocardial infarct size.

Recurrent Lower-Extremity Compartment Syndrome after Four-Compartment Fasciotomy Secondary to Acute Limb Ischemia

Lower-extremity compartment syndrome is a limb-threatening event necessitating emergent treatment using fasciotomy. Recurrent compartment syndrome is rare and has only been reported after trauma and in conjunction with underlying connective tissue disorders. In this report, we present a case of recurrent lower-extremity compartment syndrome caused by ischemia-reperfusion injury, in a patient previously treated with adequate 4-compartment fasciotomies. As such, this is the first reported case of recurrent compartment syndrome in the setting of ischemia-reperfusion injury that required treatment with 4-compartment fasciotomies on both occasions. This case demonstrates that fasciotomy is not protective against the development of recurrent compartment syndrome due to ischemia-reperfusion injury and that patients at high risk require monitoring.

Inflammatory response and extracorporeal circulation

Patients undergoing cardiac surgery with extracorporeal circulation (EC) frequently develop a systemic inflammatory response syndrome. Surgical trauma, ischaemia-reperfusion injury, endotoxaemia and blood contact to nonendothelial circuit compounds promote the activation of coagulation pathways, complement factors and a cellular immune response. This review discusses the multiple pathways leading to endothelial cell activation, neutrophil recruitment and production of reactive oxygen species and nitric oxide. All these factors may induce cellular damage and subsequent organ injury. Multiple organ dysfunction after cardiac surgery with EC is associated with an increased morbidity and mortality. In addition to the pathogenesis of organ dysfunction after EC, this review deals with different therapeutic interventions aiming to alleviate the inflammatory response and consequently multiple organ dysfunction after cardiac surgery.

Effect of ischemia preconditioning and leech therapy on cutaneous pedicle flaps subjected to prolonged ischemia in a mouse model

We sought to determine the effect of ischemic preconditioning (IPC) and hirudotherapy (leech therapy) on cutaneous pedicle flaps after they underwent prolonged ischemia (global ischemia) in a mouse model. Twenty cutaneous pedicle flaps were elevated in 20 mice, and the animals were randomized into four groups: sham, control, IPC and leech (5 flaps in each group). Except in the sham group, all flaps were subjected to global ischemia for 5 h via pedicle clamping. The control group did not receive any treatment before or after global ischemia. In the IPC group, global ischemia was preceded by three 10-min episodes of ischemia, each followed by 10 min of reperfusion. In the leech therapy group, after global ischemia, hirudotherapy was performed. Flap survival area and histopathological changes were evaluated on the 10th day after surgery. Flap survival areas were significantly higher in both the IPC and leech groups than in the control group and were significantly higher in the leech group than in the IPC group (p < 0.05). In conclusion IPC and hirudotherapy had definite effects on the survival area of cutaneous pedicle flaps that underwent prolonged ischemia in a mouse model.

Tetramethylpyrazine suppresses transient oxygen-glucose deprivation-induced connexin32 expression and cell apoptosis via the ERK1/2 and p38 MAPK pathway in cultured hippocampal neurons

Tetramethylpyrazine (TMP) has been widely used in China as a drug for the treatment of various diseases. Recent studies have suggested that TMP has a protective effect on ischemic neuronal damage. However, the exact mechanism is still unclear. This study aims to investigate the mechanism of TMP mediated ischemic hippocampal neurons injury induced by oxygen-glucose deprivation (OGD). The effect of TMP on hippocampal neurons viability was detected by MTT assay, LDH release assay and apoptosis rate was measured by flow cytometry. TMP significantly suppressed neuron apoptosis in a concentration-dependent manner. TMP could significantly reduce the elevated levels of connexin32 (Cx32) induced by OGD. Knockdown of Cx32 by siRNA attenuated OGD injury. Moreover, our study showed that viability was increased in siRNA-Cx32-treated-neurons, and neuron apoptosis was suppressed by activating Bcl-2 expression and inhibiting Bax expression. Over expression of Cx32 could decrease neurons viability and increase LDH release. Furthermore, OGD increased phosphorylation of ERK1/2 and p38, whose inhibitors relieved the neuron injury and Cx32 up-regulation. Taken together, TMP can reverse the OGD-induced Cx32 expression and cell apoptosis via the ERK1/2 and p38 MAPK pathways.