Single-cell RNA sequencing reveals the transcriptomic landscape of kidneys in patients with ischemic acute kidney injury / 中华医学杂志(英文版)

BACKGROUND@#Ischemic acute kidney injury (AKI) is a common syndrome associated with considerable mortality and healthcare costs. Up to now, the underlying pathogenesis of ischemic AKI remains incompletely understood, and specific strategies for early diagnosis and treatment of ischemic AKI are still lacking. Here, this study aimed to define the transcriptomic landscape of AKI patients through single-cell RNA sequencing (scRNA-seq) analysis in kidneys.@*METHODS@#In this study, scRNA-seq technology was applied to kidneys from two ischemic AKI patients, and three human public scRNA-seq datasets were collected as controls. Differentially expressed genes (DEGs) and cell clusters of kidneys were determined. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, as well as the ligand-receptor interaction between cells, were performed. We also validated several DEGs expression in kidneys from human ischemic AKI and ischemia/reperfusion (I/R) injury induced AKI mice through immunohistochemistry staining.@*RESULTS@#15 distinct cell clusters were determined in kidney from subjects of ischemic AKI and control. The injured proximal tubules (PT) displayed a proapoptotic and proinflammatory phenotype. PT cells of ischemic AKI had up-regulation of novel pro-apoptotic genes including USP47 , RASSF4 , EBAG9 , IER3 , SASH1 , SEPTIN7 , and NUB1 , which have not been reported in ischemic AKI previously. Several hub genes were validated in kidneys from human AKI and renal I/R injury mice, respectively. Furthermore, PT highly expressed DEGs enriched in endoplasmic reticulum stress, autophagy, and retinoic acid-inducible gene I (RIG-I) signaling. DEGs overexpressed in other tubular cells were primarily enriched in nucleotide-binding and oligomerization domain (NOD)-like receptor signaling, estrogen signaling, interleukin (IL)-12 signaling, and IL-17 signaling. Overexpressed genes in kidney-resident immune cells including macrophages, natural killer T (NKT) cells, monocytes, and dendritic cells were associated with leukocyte activation, chemotaxis, cell adhesion, and complement activation. In addition, the ligand-receptor interactions analysis revealed prominent communications between macrophages and monocytes with other cells in the process of ischemic AKI.@*CONCLUSION@#Together, this study reveals distinct cell-specific transcriptomic atlas of kidney in ischemic AKI patients, altered signaling pathways, and potential cell-cell crosstalk in the development of AKI. These data reveal new insights into the pathogenesis and potential therapeutic strategies in ischemic AKI.

The role of macrophage polarization and interaction with renal tubular epithelial cells in ischemia-reperfusion induced acute kidney injury / 生理学报

Acute kidney injury (AKI) is a common critical clinical disease characterized by a sharp decline of renal function. Ischemia-reperfusion (IR) is one of the main causes of AKI. The mortality of AKI remains high due to the lack of early diagnosis and cause specific treatment. IR rapidly initiates innate immune responses, activates complement and innate immune cells, releasing a large number of injury-related molecules such as high mobility group box-1 (HMGB1), inflammatory mediators such as caspase-3, and then recruits immune inflammatory cells including M1 macrophages (Mϕ) to the microenvironment of injury, causing apoptosis and necrosis of renal tubular epithelial cells (TECs). Dead cells and associated inflammation further activate the adaptive immune system, which not only aggravates tissue damage, but also initiates M2 Mϕ participated inflammatory clearance, tissue repair and regeneration. Mϕ, professional phagocytes, and TECs, semi-professional phagocytes, can phagocytose around damaged cells including apoptotic Mϕ and TECs, which are key innate immune cells to regulate the outcome of injury, repair or fibrosis. In recent years, it has been found that erythropoietin (EPO) not only binds to the homodimeric receptor (EPOR)2 to induce erythropoiesis, but also binds to the heterodimeric receptor EPOR/βcR, also known as innate repair receptor, which plays renoprotective roles. Properdin is the only positive regulator in the complement activation of alternative pathway. It also can effectively identify and bind to early apoptotic T cells and facilitate phagocytic clearing by Mϕ through a non-complement activation-dependent mechanism. Our previous studies have shown that Mϕ and TECs associated with EPO and its receptors and properdin are involved in IR injury and repair, but the underlying mechanism needs to be further explored. As an important carrier of cell-to-cell signal transmission, exosomes participate in the occurrence and development of a variety of renal diseases. The role of exosomes involved in the interaction between Mϕ and TECs in IR-induced AKI is not fully defined. Based on the available results in the role of Mϕ and TECs in renal IR-induced AKI, this review discussed the role of Mϕ polarization and interaction with TECs in renal IR injury, as well as the participation of EPO and its receptors, properdin and exosomes.

The role of adiponectin in ischemia-reperfusion syndrome: a literature review / O papel da adiponectina na síndrome de isquemia e reperfusão: revisão de literatura

ABSTRACT Adiponectin, among other diverse adipokines, is produced in greater quantity and has an effect on the adipose tissue and other tissues in the body. Adiponectin plays three main roles: regulatory metabolic and sensitizing function of insulin in the liver and muscles; it acts as an anti-inflammatory cytokine and in vascular protection, besides important cardiac protection in the presence of ischemia-reperfusion syndrome. Since many situations resulting from traumatic accidents or pathologies are due to cell damage caused by ischemia-reperfusion syndrome, it is relevant to study new therapeutic alternatives that will contribute to reducing these lesions. The objective of this study is to carry out a literature review on the role of adiponectin in ischemia-reperfusion syndrome.

RESUMO A adiponectina, em meio a outras diversas adipocinas, é a produzida em maior quantidade e exerce efeitos no próprio tecido adiposo e em outros diversos tecidos do organismo. Dentre suas funções, a adiponectina apresenta três principais papéis: função metabólica regulatória e sensibilizadora da insulina no fígado e nos músculos atua como citocina anti-inflamatória e vasculoprotetora, além de exercer importante fator cardioprotetor na presença da síndrome de isquemia e reperfusão. Visto que inúmeras situações decorrentes de acidentes traumáticos ou patologias recaem no dano celular causado pela síndrome de isquemia e reperfusão, observa-se a importância de estudar novas alternativas terapêuticas que venham a contribuir para a diminuição dessas lesões. O objetivo do presente estudo é realizar uma revisão de literatura sobre o papel da adiponectina na síndrome de isquemia e reperfusão.

TLR7 mediates increased vulnerability to ischemic acute kidney injury in diabetes

SUMMARY OBJECTIVE Diabetes is a risk factor for acute kidney injury (AKI). However, its mechanism of pathogenesis has not been elucidated. The aim of the study was to investigate the role of inflammation and the toll-like receptor 7 (TLR7) in ischemic AKI for diabetes. METHODS A high glucose hypoxia-reoxygenation model of human renal tubular epithelial (HK-2) cells was used to generate AKI induced by ischemia-reperfusion in diabetes. The activity of cells was measured by CCK-8 assay and LDH activity. Inflammatory cytokines were assessed by ELISA. TLR7, MyD88, and NF-κB expressions were examined by western blotting. Apoptosis was evaluated by flow cytometry. RESULTS The high glucose group and low glucose group were subjected to hypoxia-reoxygenation. The low glucose group developed only mild cell damage, apoptosis, and inflammatory response. In contrast, an equivalent hypoxia-reoxygenation injury provoked severe cell damage, apoptosis, and inflammatory response in the high glucose group. Expression of TLR7 and its related proteins were measured in the high glucose group before and after hypoxia-reoxygenation. The high glucose group exhibited more significant increases in TLR7 expression following hypoxia-reoxygenation than the low glucose group. In addition, the expression of TLR7 and its related proteins after hypoxia-reoxygenation were higher in the high glucose group than in the low glucose group. Inhibition of TLR7 provides significant protection against ischemic injury in diabetes. CONCLUSION Our results suggest that diabetes increases the vulnerability to ischemia-induced renal injury. This increased vulnerability originates from a heightened inflammatory response involving the TLR7 signal transduction pathway.

RESUMO OBJETIVO O diabetes é um fator de risco para a lesão renal aguda (LRA). No entanto, seu mecanismo de patogênese não foi elucidado. O objetivo do estudo foi investigar o papel da inflamação e do receptor Toll-like 7 (TLR7) na LRA isquêmica no diabetes. MÉTODOS Um modelo de hipóxia-reoxigenação de células epiteliais tubulares renais humanas (HK-2) na presença de concentrações altas de glicose foi utilizado para gerar LRA induzida por isquemia-reperfusão em diabetes. A atividade das células foi medida pelo ensaio Cell Counting Kit-8 (CCK-8) e pela atividade da lactato desidrogenase (LDH). As citocinas inflamatórias foram avaliadas por ensaio imunoenzimático (Elisa). A expressão de TLR7, do fator de diferenciação mieloide 88 (MyD88) e do fator de transcrição nuclear-κB (NF-κB) foi examinada por Western blotting. A apoptose foi avaliada por citometria de fluxo. RESULTADOS Os grupos glicose alta e glicose baixa foram submetidos à hipóxia-reoxigenação. O grupo de baixa glicose desenvolveu apenas danos celulares ligeiros, apoptose e uma resposta inflamatória. Em contraste, no grupo de alta glicose, uma lesão equivalente de hipóxia-reoxigenação provocou danos celulares graves, apoptose e uma resposta inflamatória. A expressão de TLR7 e suas proteínas relacionadas foi medida no grupo de alta glicose antes e após a hipóxia-reoxigenação. O grupo de alta glicose exibiu maiores aumentos na expressão de TLR7 após hipóxia-reoxigenação do que o grupo de baixa glicose. Além disso, a expressão de TLR7 e suas proteínas relacionadas após a hipóxia-reoxigenação foi maior no grupo com alto nível de glicose do que no grupo com baixo nível de glicose. A inibição do TLR7 fornece proteção significativa contra a lesão isquêmica no diabetes. CONCLUSÃO Nossos resultados sugerem que o diabetes aumenta a vulnerabilidade à lesão renal induzida por isquemia. Essa vulnerabilidade acrescida tem por origem uma resposta inflamatória aumentada envolvendo a via de transdução de sinal do TLR7.

Liver ischemia and reperfusion injury. Pathophysiology and new horizons in preconditioning and therapy

Abstract It is well known that during hepatic operative procedures, it is often critical that the irrigation is interrupted to avoid possible bleeding, blood transfusions, variable intensities, and their short and long-term consequences. It was believed in the past that the flow interruption should not exceed 20 minutes, which limited the use of this maneuver. However, it has been postulated that ischemia could be maintained for more than 60 minutes in healthy livers. The present paper review includes: 1) A brief introduction to justify the rationale of the review design; 2) Aspects of the pathophysiology of the three stages of the liver ischemia-reperfusion injury; 3) The innate and acquired immunity; 4) Oxidative stress; 5) Apoptosis and autophagy, Some essential biomarkers (Tumor Necrosis Factor-α, nitric oxide, metalloproteinases); and, finally; 6) Preventive ("cheating") strategies, non-pharmacological and pharmacological options to treat the liver IR injury.

Effect of hyperbaric oxygenation on the expression of glutathione peroxidase 4 and lactoperoxidase genes in the lung of isogenic mice after ischemia/reperfusion injury in the small bowel

Abstract Purpose: To evaluate the effect of hyperbaric oxygenation (HBO) on the expression of the genes antioxidant glutathione peroxidase 4 (Gpx4) and lactoperoxidase (Lpo) in the lung of mice subjected to intestinal ischemia and reperfusion (IIR). Methods: Control group (CG) in which were subjected to anesthesia, laparotomy and observation for 120 minutes; an ischemia and reperfusion group (IRG) subjected to anesthesia, laparotomy, small bowel ischemia for 60 minutes and reperfusion for 60 minutes; and three groups treated with HBO during ischemia (HBOG + I), during reperfusion (HBOG + R) and during ischemia and reperfusion (HBOG + IR). Studied 84 genes of oxidative stress by the method (RT-qPCR). Genes with expression levels three times below or above the threshold cycle were considered significantly hypoexpressed or hyperexpressed, respectively (Student's t-test p<0.05). Results: Gpx4 and Lpo were hiperexpressed on IRG, showing a correlation with these genes with lung oxidative stress. Treated with HBO, there was a significant reduction on genic expression on HBOG+I. Conclusion: Hyperbaric oxygenation showed to be associated with decreased expression of these antioxidant genes, suggesting a beneficial effect on the mechanism of pulmonary oxidative stress whenever applied during the ischemia.

Hyperbaric oxygenation and the genic expression related to oxidative stress in the heart of mice during intestinal ischemia and reperfusion

Abstract Purpose: To investigate the effects of hyperbaric oxygenation (HBO) on intestinal ischemia and reperfusion (IR) injury, we evaluated the expression of 84 genes related to oxidative stress and the antioxidant response in mouse hearts. Methods: Four groups were subjected to 60 minutes of intestinal ischemia followed by 60 minutes of reperfusion: IRG, ischemia and reperfusion group without HBO; HBO-IG, which received HBO during ischemia; HBO-RG, which received HBO during reperfusion; and HBO-IRG, which received HBO during ischemia and reperfusion. The control group (CG) underwent anesthesia and laparotomy and was observed for 120 minutes. The (RT-qPCR) method was applied. Genes with expression levels three times below or above the threshold cycle were considered significantly hypoexpressed or hyperexpressed, respectively (Student's t-test p<0.05). Results: Eight genes (9.52%) were hyperexpressed in the IRG. When the HBO groups were compared to the IRG, we found a decrease in the expression of eight genes in the HBO-IG, five genes in the HBO-RG, and seven genes in the HBO-IRG. Conclusion: The reduction in the expression of genes related to oxidative stress and antioxidant defense following HBO in mouse hearts resulting from intestinal IR injury was more favorable during the ischemic period than during the reperfusion period.

Influence of remote ischemic conditioning and tramadol hydrochloride on oxidative stress in kidney ischemia/reperfusion injury in rats

Abstract Purpose: To evaluate the effects of tramadol hydrochloride associated to remote ischemic perconditioning on oxidative stress. Methods: Twenty five male rats (Wistar) underwent right nephrectomy and were distributed into five groups: Sham group (S); Ischemia/Reperfusion group (I/R) with 30 minutes of renal ischemia; Remote ischemic perconditioning group (Per) with three cycles of 10 minutes of I/R performed during kidney ischemia; Tramadol group (T) treated with tramadol hydrochloride (40mg/kg); remote ischemic perconditioning + Tramadol group (Per+T) with both treatments. Oxidative stress was assessed after 24 hours of reperfusion. Results: Statistical differences were observed in MDA levels between I/R group with all groups (p<0.01), in addition there was difference between Tramadol with Sham, Per and Per+T groups (p<0.05), both in plasma and renal tissue. Conclusion: Remote ischemic perconditioning was more effective reducing renal ischemia-reperfusion injury than administration of tramadol or association of both treatments.

Efecto terapéutico de los exosomas en el ACV isquémico en animales de experimentación / Therapeutic effect of exosomes on ischemic stroke in experimental animals

La posibilidad de que los exosomas funcionen como una nueva forma de comunicación intercelular para establecer y mantener circuitos cerebrales está comenzando a ser explorada. Los exosomas son liberados desde células e interactúan con otras células receptoras para mediar cambios fisiológicos. Todas las células cerebrales liberan exosomas incluyendo las celulas madre neuronales, las neuronas, astrocitos, microglia, oligodendrocitos y las celulas endoteliales. El objetivo de esta revisión es reunir evidencia actualizada sobre las funciones de protección, antiinflamación y regeneración de los exosomas en el ataque cerebrovascular (ACV) isquémico en ratas. Se realizó una búsqueda sistemática de la literatura sensible y específica en base de datos Medline, EMBASE, Web of Science, Scopus, TRIP database, SciELO y LILACS con términos libres y meSH. Los exosomas generados de CSMs pueden ser utilizados para el tratamiento del ACV. Los exosomas de oligodendrocitos también ejercen una variedad de efectos sobre las neuronas receptoras e influencian un amplio espectro de la fisiología neuronal. En conjunto estos resultados sugieren que los exosomas de las CSMs mediados con miR-133b se transfieren a astrocitos y neuronas, las que regulan la expresión génica, beneficiando tanto la remodelación de neuritas, como la recuperación funcional despues de un ACV. Sería importante en el futuro desarrollar métodos para cuantificar y caracterizar los exosomas en el cerebro con isquemia. Esto permitiría correlacionar entre la cantidad de exosomas en el cerebro y la recuperación funcional entregando información sobre sus mecanismos de acción.

The possibility that exosomes function as a new form of inter cellular communication to establish and maintain brain circuits is beginning to be investigated. Exosomes are released from cells and interact with other receptor cells to mediate physiological changes. All brain cells release exosomes including neural stem cells, neurons, astrocytes, microglia, oligodendrocytes and endothelial cells. The aim of this review is to gather current evidence on the protective, anti-inflammatory and regenerative functions of exosomes in ischemic stroke in rats. A systematic search of sensitive and specific literature was carried out in the following database search engines: Medline, EMBASE, Web of Science, Scopus, TRIP database, SciELO and LILACS with free and MeSH terms data. MSC generated exosomes can be used in the treatment of stroke. Oligodendrocyte exosomes also exert a variety of effects on receptor neurons and influence a wide spectrum of neuronal physiology. Together these results suggest that MSC exosome-mediated transfer of miR-133b to astrocytes and neurons, thus regulating gene expression, benefiting both neurite remodeling, such as functional recovery following a stroke. It would be important in the future to develop methods to quantify and characterize exosomes in brain ischemia. This would allow correlation between the amount of exosomes in the brain and functional recovery providing information relevant to its action mechanisms.

Expressao genica associada ao estresse oxidativo no coracao de camundongo apos isquemia intestinal / Gene expression related to oxidative stress in the heart of mice after intestinal ischemia

FUNDAMENTO: O fenômeno da isquemia e reperfusão intestinal é um evento frequente na clínica e está associado a repercussões deletérias em órgãos a distância, em especial ao coração. OBJETIVO: Investigar a expressão gênica do estresse oxidativo e defesa antioxidante no coração de camundongos isogênicos, submetidos a isquemia e reperfusão intestinal (IR). MÉTODOS: Doze camundongos (C57BL/6) foram distribuídos em dois grupos: Grupo IR (GIR) com 60 min de oclusão da artéria mesentérica superior, seguidos de 60 min de reperfusão. Grupo Controle (GC) submetidos a anestesia e a laparotomia sem o procedimento de IR observados por 120 min. As amostras de intestino e coração foram processadas pelo método (RT-qPCR / Reverse transcriptase - quantitative Polymerase Chain Reaction) para determinar a expressão gênica de 84 genes relacionados ao estresse oxidativo ("t" de Student, p < 0,05). RESULTADOS: Observou-se no tecido intestinal (GIR) uma expressão significantemente aumentada em 65 (74,71%) genes em relação ao tecido normal (GC), e 37 (44,04%) genes estiveram hiperexpressos (maior que três vezes o limiar permitido pelo algoritmo). No tocante aos efeitos da I/R intestinal a distância no tecido cardíaco verificou-se a expressão significantemente aumentada de 28 genes (33,33%), mas somente oito genes (9,52%) se hiperexpressaram três vezes acima do limiar. Quatro (7,14%) desses oito genes se expressaram simultaneamente nos tecidos intestinal e cardíaco. No GIR notaram-se cardiomiócitos com núcleos de menor tamanho, picnóticos, ricos em heterocromatina e raros nucléolos, indicando sofrimento cardíaco. CONCLUSÃO: A I/R intestinal promoveu a hiperexpressão estatisticamente significante de oito genes associados ao ...

BACKGROUND: Intestinal ischemia-reperfusion is a frequent clinical event associated to injury in distant organs, especially the heart. OBJECTIVE: To investigate the gene expression of oxidative stress and antioxidant defense in the heart of inbred mice subjected to intestinal ischemia and reperfusion (IR). METHODS: Twelve mice (C57BL / 6) were assigned to: IR Group (GIR) with 60 minutes of superior mesenteric artery occlusion followed by 60 minutes of reperfusion; Control Group (CG) which underwent anesthesia and laparotomy without IR procedure and was observed for 120 minutes. Intestine and heart samples were processed using the RT-qPCR / Reverse transcriptase-quantitative Polymerase Chain Reaction method for the gene expression of 84 genes related to oxidative stress and oxidative defense (Student's "t" test, p < 0.05). RESULTS: The intestinal tissue (GIR) was noted to have an up-regulation of 65 genes (74.71%) in comparison to normal tissue (CG), and 37 genes (44.04%) were hyper-expressed (greater than three times the threshold allowed by the algorithm). Regarding the remote effects of intestinal I/R in cardiac tissue an up-regulation of 28 genes (33.33%) was seen, but only eight genes (9.52%) were hyper-expressed three times above threshold. Four (7.14%) of these eight genes were expressed in both intestinal and cardiac tissues. Cardiomyocytes with smaller and pyknotic nuclei, rich in heterochromatin with rare nucleoli, indicating cardiac distress, were observed in the GIR. CONCLUSION: Intestinal I/R caused a statistically significant over expression of 8 genes associated with oxidative stress in remote myocardial tissue. .

Oxidative stress evaluation of ischemia and reperfusion in kidneys under various degrees of hypothermia in rats

PURPOSE:To design an animal model of ischemia-reperfusion (I/R) in kidneys and evaluate the role that predetermined ranges of local hypothermia plays on markers of stress-oxydative as well as on histologic sections. METHODS: Twenty eight male rats Wistar, under general anesthesia, undergone right nephrectomy (G0, control group) followed by left kidney ischemia during 40 min. Four temperatures groups were designed, with seven animals randomized for each group: normothermic (G1, ±37ºC), mild hypothermia (G2, 26ºC), moderate hypothermia (G3, 15ºC) and deep hypothermia (G4, 4ºC). Left kidney temperature was assessed with an intraparenchymal probe. Left nephrectomy was performed after 240 min of reperfusion. After I/R a blood sample was obtained for f2-IP. Half of each kidney was sent to pathological evaluation and half to analyze CAT, SOD, TBARS, NO3, NO2. RESULTS:Histopathology showed that all kidneys under I/R were significantly more injured than the G0 (p<0.001). TBARS had increased levels in all I/R groups compared with the G0 (p<0.001). CAT had a significant difference (p<0.03) between G1 and G4. Finally, no difference was found on SOD, NO3, NO2 nor on f2-IP. CONCLUSION: This model of I/R was efficient to produce oxidative-stress in the kidney, showing that 4ºC offered significant decrease in free radicals production, although tissue protection was not observed.

Oxidative stress gene expression profile in inbred mouse after ischemia/reperfusion small bowel injury / Perfil da expressão gênica do estresse oxidativo em camundongos isogênicos após lesão de isquemia e reperfusão intestinal

PURPOSE: To determine the profile of gene expressions associated with oxidative stress and thereby contribute to establish parameters about the role of enzyme clusters related to the ischemia/reperfusion intestinal injury. METHODS: Twelve male inbred mice (C57BL/6) were randomly assigned: Control Group (CG) submitted to anesthesia, laparotomy and observed by 120min; Ischemia/reperfusion Group (IRG) submitted to anesthesia, laparotomy, 60min of small bowel ischemia and 60min of reperfusion. A pool of six samples was submitted to the qPCR-RT protocol (six clusters) for mouse oxidative stress and antioxidant defense pathways. RESULTS: On the 84 genes investigated, 64 (76.2%) had statistic significant expression and 20 (23.8%) showed no statistical difference to the control group. From these 64 significantly expressed genes, 60 (93.7%) were up-regulated and 04 (6.3%) were down-regulated. From the group with no statistical significantly expression, 12 genes were up-regulated and 8 genes were down-regulated. Surprisingly, 37 (44.04%) showed a higher than threefold up-regulation and then arbitrarily the values was considered as a very significant. Thus, 37 genes (44.04%) were expressed very significantly up-regulated. The remained 47 (55.9%) genes were up-regulated less than three folds (35 genes - 41.6%) or down-regulated less than three folds (12 genes - 14.3%). CONCLUSION: The intestinal ischemia and reperfusion promote a global hyper-expression profile of six different clusters genes related to antioxidant defense and oxidative stress.

OBJETIVO: Determinar o perfil de expressão dos genes associados com estresse oxidativo e contribuir para estabelecer parâmetros sobre o papel das familias de enzimas relacionadas com a lesão de isquemia / reperfusão intestinal. MÉTODOS: Doze camundongos machos isogênicos (C57BL/6) foram distribuídos aleatoriamente: Grupo Controle (CG) submetido à laparotomia anestesia, e observado por 120min; Grupo isquemia/reperfusão (IRG) submetido à anestesia, laparotomia, 60min de isquemia do intestino delgado e 60min de reperfusão. Um pool dos seis camundongos de cada grupo foi submetido ao protocolo de qPCR-RT (seis famílias) para o estresse oxidativo e defesa antioxidante. RESULTADOS: Dos 84 genes investigados, 64 (76,2%) tiveram expressão estatística significante e 20 (23,8%) não apresentaram diferença estatística com o grupo controle. Dos 64 genes expressos de forma significante, 60 (93,7%) foram hiper-expressos e 04 (6,3%) foram hipo-expressos. Do grupo sem expressão estatisticamente significante, 12 genes foram hiper e 8 genes foram hipo-expressos. Surpreendentemente, 37 (44,04%) apresentaram expressão três maior que o limiar de normalidade e arbitrariamente os valores foram considerados como altamente significantes. Assim, 37 genes (44,04%) foram hiper-expressos de modo muito significante. Nos demais, 47 (55,9%) dos genes foram hiper-expressos menos de três vezes (35 genes - 41,6%) ou hipo-expressos menos de três vezes(12 genes - 14,3%). CONCLUSÃO: A isquemia e reperfusão intestinal promoveu um perfil de hiper-expressão global das seis familias de genes relacionados com estresse oxidativo antioxidante e defesa antioxidante.

The protective effect of cilostazol on isolated rabbit femoral arteries under conditions of ischemia and reperfusion: the role of the nitric oxide pathway

OBJECTIVES: The clinical significance of ischemia/reperfusion of the lower extremities demands further investigation to enable the development of more effective therapeutic alternatives. This study investigated the changes in the vascular reactivity of the rabbit femoral artery and nitric oxide metabolites under partial ischemia/ reperfusion conditions following cilostazol administration. METHODS: Ischemia was induced using infrarenal aortic clamping. The animals were randomly divided into seven groups: Control 90 minutes, Ischemia/Reperfusion 90/60 minutes, Control 120 minutes, Ischemia/Reperfusion 120/90 minutes, Cilostazol, Cilostazol before Ischemia/Reperfusion 120/90 minutes, and Ischemia 120 minutes/Cilostazol/ Reperfusion 90 minutes. Dose-response curves for sodium nitroprusside, acetylcholine, and the calcium ionophore A23187 were obtained in isolated femoral arteries. The levels of nitrites and nitrates in the plasma and skeletal muscle were determined using chemiluminescence. RESULTS: Acetylcholine-and A23187-induced relaxation was reduced in the Ischemia/Reperfusion 120/90 group, and treatment with cilostazol partially prevented this ischemia/reperfusion-induced endothelium impairment. Only cilostazol treatment increased plasma levels of nitrites and nitrates. An elevation in the levels of nitrites and nitrates was observed in muscle tissues in the Ischemia/Reperfusion 120/90, Cilostazol/Ischemia/Reperfusion, and Ischemia/ Cilostazol/Reperfusion groups. CONCLUSION: Hind limb ischemia/reperfusion yielded an impaired endothelium-dependent relaxation of the femoral artery. Furthermore, cilostazol administration prior to ischemia exerted a protective effect on endotheliumdependent vascular reactivity under ischemia/reperfusion conditions.

Early Sustained Injections of Erythropoietin Improve Angiogenesis and Restoration of Perfusion in the Ischemic Mouse Hindlimb

This study was conducted to investigate the effects of erythropoietin (Epo) on both acute and chronic limb ischemia (ALI and CLI) and to evaluate the differences in mechanisms according to the method of Epo administration. Hindlimb ischemia was made in BALB/c mice with femoral artery ligation. The mice were divided into four groups: Group 1 (control, no treatment), Group 2 (ALI, early multiple doses), Group 3 (ALI, early single high dose), Group 4 (CLI, late multiple doses). Blood flow ratio significantly increased in Group 2 in 4 weeks. Expression of pAkt and Erythropoietin receptor were significantly higher in Group 2 on postoperative day (POD) 7. The number of CD31- and vascular endothelial growth factor-positive cells were significantly higher in Group 2 on POD 7 and 56. Group 3 and 4 showed a tendency of higher cell counts than the control. The early sustained Epo was effective in improving blood flow through angiogenesis. In chronic phase, weekly multiple dosing of Epo induced angiogenesis, however, the blood flow ratio did not increase significantly. The results of this study suggest that Epo administration during the acute phase followed by maintenance for several days may be important for increasing blood flow and angiogenesis.

Bioelectrical Impedance May Predict Cell Viability During Ischemia and Reperfusion in Rat Liver

Ischemia and reperfusion (I/R) injury is a major cause of hepatic failure after liver surgery, but no method could monitor or predict it real-time during surgery. We measured bioelectrical impedance (BEI) and cell viability to assess the usefulness of BEI during I/R in rat liver. A 70% partial liver ischemia model was used. BEI was measured at various frequencies. Adenosine triphosphate (ATP) content, and palmitic acid oxidation rate were measured, and histological changes were observed in order to quantify liver cell viability. BEI changed significantly during ischemia at low frequency. In the ischemia group, BEI increased gradually during 60 min of ischemia and had a tendency to plateau thereafter. The ATP content decreased below 20% of the baseline level. In the I/R group, BEI recovered to near baseline level. After 24 hr of reperfusion, the ATP contents decreased to below 50% in 30, 60 and 120 min of ischemia and the palmitic acid metabolic rates decreased to 91%, 78%, and 74%, respectively, compared with normal liver. BEI may be a good tool for monitoring I/R during liver surgery. The liver is relatively tolerant to ischemia, however after reperfusion, liver cells may be damaged depending upon the duration of ischemia.

Ginsenoside Rb1 attenuates intestinal ischemia-reperfusion- induced liver injury by inhibiting NF-kappa B activation

Intestinal ischemia-reperfusion (I/R) is an important event in the pathogenesis of multiple organ dysfunction syndrome (MODS). The aim of this study is to determine the effects of ginsenoside Rb1 on liver injury induced by intestinal I/R in rats. Adult male Wistar rats were randomly divided into four groups: (1) a control, sham-operated group (sham group); (2) an intestinal I/R group subjected to 1 h intestinal ischemia and 2 h reperfusion (I/R group); (3) a group treated with 20 mg/kg ginsenoside Rb1 before reperfusion (Rb1-20 group); and (4) a group treated with 40 mg/kg ginsenoside Rb1 before reperfusion (Rb1-40 group). Liver and intestinal histology was observed. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) level in serum and malondialdehyde (MDA) level in intestinal tissues were measured. Myeloperoxidase (MPO), TNF-alpha, MDA level and immunohistochemical expression of NF-kappa B and intracellular adhesion molecale-1 (ICAM-1) in liver tissues was assayed. In addition, a western blot analysis of liver NF-kappa B expression was performed. Results indicated intestinal I/R induced intestinal and liver injury, which was characterized by increase of AST and ALT in serum, MDA level in intestine, MPO, TNF-alpha and MDA level and ICAM-1 and NF-kappa B expression in the liver tissues. Ginsenoside Rb1 (20, 40 mg/kg) ameliorated liver injury, decreased MPO, TNF-alpha and MDA level, NF-kappa B and ICAM-1 expression in liver tissues. In conclusion, ginsenoside Rb1 ablated liver injury induced by intestinal I/R by inhibiting NF-kappaB activation.

Participación de Ca2+ en el precondicionamiento del miocardio por ejercicio / Role of Ca2+ in exercise induced myocardial preconditioning

Antecedentes: Episodios breves de ejercicio previos a la oclusión prolongada de una arteria coronaria disminuyen el tamaño del infarto inducido por ésta. Objetivo: Dado que la administración intracoronaria de Ca2+ induce precondicionamiento, y el ejercicio probablemente aumenta el calcio citosólico, decidimos estudiar si el precondicionamiento por ejercicio está mediado por Ca2+. Material y método: Para ello analizamos el efecto del bloqueo de los canales de calcio del sarcolema, con verapamilo, sobre la acción precondicionante del ejercicio. Se midió tamaño del infarto en perros entrenados a correr en cinta sin finasignados aleatoriamente a los siguientes grupos. I: Isquemia inducida por oclusión coronaria durante 1 hora seguida de reperfusión por 4 hrs. E+I: Similar al grupo I, pero los perros hicieron ejercicio antes de inducir la isquemia. V+I: Similar al grupo I, pero se administró verapamilo antes de inducir la isquemia. V+E+I : Similar al grupo E+I, pero se administró verapamilo antes del ejercicio. Para estudiar el posible rol mediador del retículo sarcoplasmático (RS) en los efectos de la isquemia y de verapamilo, se midió la captación y la liberación de calcio en vesículas de RS de la pared del ventrículo izquierdo sometida a isquemia con o sin verapamilo en perros con y sin precondicionamiento con ejercicio. Los resultados, expresados como promedio +/- ES, se analizaron mediante ANOVA seguido del test de Holm para comparaciones múltiples. Resultados: Verapamilo revirtió el efecto protector del ejercicio sobre el tamaño del infarto (E+I: 6,0 +/- 9,4; N=12 vs V+E+I: 27,7+/-9,6; N=15; P<0.05), pero no modificó el efecto protector del ejercicio precondicionante sobre los trastornos de transporte de calcio en el RS inducidos por la isquemia. Conclusiones: Nuestros resultados sugieren que el precondicionamiento inducido por ejercicio está mediado por la entrada de calcio a la célula...

Background: Brief episodes of exercise prior to a prolonged occlusion of a coronary artery substantially reduce infarct size. Aim: Since the intracoronary administration of Ca2+ induces preconditioning and exercise most likely increases cytosolic calcium we put forward the hypothesis that preconditioning by exercise is mediated by calcium. Methods: For this purpose we analyzed the effect of verapamil, a sarcolemmal calcium channel blocker, on preconditioning by exercise. We measured infarct size in dogs randomly assigned to one of the following groups. I: Ischemia induced by coronary occlusion during 1 hour followed by reperfusion during 4 hours. E+I: Similar to group I, but the dogs run on a treadmill prior to ischemia. V+I: Similar to group I but verapamil was administered before the coronary occlusion. V+E+I: Similar to group E+I but verapamil was administered before exercise. SR vesicles from ventricular tissue were isolated from dogs subjected to the same experimental protocols and calcium release and active calcium uptake were measured. Results were expressed as Mean +/- SE and analyzed by ANOVA followed by Holm test for multiple comparisons. Results: Verapamil reverted the protective effect of exercise on infarct size (E+I: 6,0 +/- 9,4; N=12 vs V+E+I: 27,7 +/- 9,6;N=15; P<0.05) however it did not modify the protective effect of exercise on the alterations produced by ischemia on calcium transport in the RS. Conclusions: These results suggest that the preconditioning effect of exercise is mediated by calcium entering the cell through the sarcolemma but not by exercise effects on SR calcium transport.

Pyruvate kinase activation and lipoperoxidation after selective hepatic ischemia in Wistar rats / Ativação da piruvato quinase e lipoperoxidação após isquemia hepática seletiva em ratos Wistar

PURPOSE: Hepatic ischemia and reperfusion can cause several problems in hepatic surgery. The aim of this study was to determine pyruvate kinase activation and lipid peroxidation after hepatic ischemia. METHODS: Twenty-four Wistar rats were submitted to 90 minutes of selective liver ischemia and 15 minutes of reperfusion. Twelve animals were submitted to selective liver ischemia and reperfusion (Group A) and the other 12 were submitted to sham operation (Group B). After 15 minutes of reperfusion, the following parameters were measured: mean arterial pressure (MAP), alanine aminotransferase (ALT), glycemia (GLY), hepatic glycogen (GH), pyruvate kinase (PK) activation, hepatic glutathione (GSH) and malondialdehyde (MDA). Analysis of the results were made by the Student t-test and has been considered significant difference for p<0.05. RESULTS: A and B were differents for all parameters analized. CONCLUSION: The animals of group A showed reperfusion syndrome with a fall in MAP, activation of glycid metabolism through the glycolitic pathway and presence of lipid peroxidation compared to group B.

OBJETIVO: A isquemia e reperfusão hepática podem causar graves repercussões hepatocelulares em cirurgias hepáticas. O objetivo deste estudo foi determinar o comportamento da piruvato EM PORTUGUES quinase e a lipoperoxidação após isquemia hepática. MÉTODOS: Foram utilizados vinte e quatro ratos Wistar machos divididos em dois grupos. Doze animais foram submetidos a 90 minutos de isquemia hepática seletiva e reperfusão hepática de por 15 minutos (pressão arterial média (PAM), alanina aminotransferase (ALT), glicemia (GLI), gicogênio hepático (GH), ativação da piruvato quinase (PQ), glutationa hepática (GSH) e malondialdeído (MDA). Os resultados foram analisados utilizando o teste t de Student sendo as diferenças consideradas significativas para p<0,05. RESULTADOS: Verificou-se diferença significativa entre os grupos em todos os parâmetros analisados. CONCLUSÃO: Verificou-se que os animais do grupo A mostraram síndrome de reperfusão com queda da PAM, ativação do metabolismo da glicose através da via glicolítica e presença de lipoperoxidação quando comparada com o grupo B.

Effects of L-alanyl-glutamine upon the blood and kidney biochemical parameters in the rat hind limb model of ischemia/reperfusion

OBJETIVO: Investigar alterações dos parâmetros metabólicos no sangue e rim de ratos submetidos à isquemia/reperfusão do membro pélvico. MÉTODOS: Quarenta e oito ratos machos foram distribuídos aleatoriamente em 2 grupos pré-tratados com administração intragástrica de solução salina 2,0 mL (G-1) ou L-alanil-glutamina 0,75 mgKg-1(G-2), uma vez ao dia (7:00h) durante 7 dias. Uma hora após a última gavagem todos os ratos foram anestesiados com éter dietílico, laparotomizados e submetidos ao pinçamento da artéria de ilíaca esquerda, durante 3 horas. Amostras foram coletadas ao término de isquemia e durante a reperfusão (1-3-6h) para determinação das concentrações in vivo de piruvato, lactato, glicose e corpos cetônicos (rim e sangue) e ATP (rim). RESULTADOS: Lactacemia e cetonemia aumentaram no grupo G-2 quando comparadas às aferidas em ratos não-tratados, durante a reperfusão. As concentrações de piruvato diminuíram e de lactato aumentaram significativamente no rim, durante a reperfusão (1h, 3h) em ratos do G-2 comparados aos respectivos controles. Houve um aumento significante nas concentrações renais de glicose, ATP e corpos cetônicos nos ratos tratados com L-alanil-glutamina durante a reperfusão (3h). CONCLUSÕES: A isquemia do membro pélvico em ratos pré-tratados com L-alanil-glutamina induz aumento da lactacemia e da concentração de lactato renal, indicando atividade glicolítica aumentada na medula renal. A hipercetonemia induzida pela oferta do dipeptídeo sugere cetogênese elevada, sinalizada por possível queda nas concentrações plasmáticas de insulina resultante da maior oxidação de glicose e utilização desse hormônio em tecidos periféricos.

The balance between the production of tumor necrosis factor-alpha and interleukin-10 determines tissue injury and lethality during intestinal ischemia and reperfusion

A major goal in the treatment of acute ischemia of a vascular territory is to restore blood flow to normal values, i.e. to "reperfuse" the ischemic vascular bed. However, reperfusion of ischemic tissues is associated with local and systemic leukocyte activation and trafficking, endothelial barrier dysfunction in postcapillary venules, enhanced production of inflammatory mediators and great lethality. This phenomenon has been referred to as "reperfusion injury" and several studies demonstrated that injury is dependent on neutrophil recruitment. Furthermore, ischemia and reperfusion injury is associated with the coordinated activation of a series of cytokines and adhesion molecules. Among the mediators of the inflammatory cascade released, TNF-alpha appears to play an essential role for the reperfusion-associated injury. On the other hand, the release of IL-10 modulates pro-inflammatory cytokine production and reperfusion-associated tissue injury. IL-1beta, PAF and bradykinin are mediators involved in ischemia and reperfusion injury by regulating the balance between TNF-alpha and IL-10 production. Strategies that enhance IL-10 and/or prevent TNF-alpha concentration may be useful as therapeutic adjuvants in the treatment of the tissue injury that follows ischemia and reperfusion.