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Background: Chronic mesenteric ischemia (CMI) is a debilitating disease with a heavy burden on quality of life. Stenting of the superior mesenteric artery (SMA) is the first option for treatment, but there is a lack of consensus defining precise indications for open revascularization (OR). Objectives: To describe a series of 4 patients with CMI treated with OR and to present an algorithm for the management of this condition. Methods: Three patients presented with typical intestinal angina and weight loss. One patient was subjected to prophylactic revascularization during open abdominal aortic aneurysm repair. Surgical techniques included: 1) Bypass from the infrarenal aorta to the SMA; 2) Bypass from an aorto-bifemoral polyester graft to the SMA; 3) Bypass from the right iliac artery to the SMA; 4) Bypass from the right graft limb of an aorto-biiliac polyester graft to the median colic artery at Riolan's arcade. PTFE was used in all surgeries. All grafts were placed in a retrograde configuration, tunneled under the left renal vein, making a smooth C-loop. A treatment algorithm was constructed based on the institution's experience and a review of recent literature. Results: All patients demonstrated resolution of symptoms and recovery of body weight. All grafts are patent after mean follow-up of two years. Conclusions: Open revascularization using the C-loop configuration is a valuable technique for CMI and may be considered in selected cases. The algorithm constructed may help decision planning in other quaternary centers.

Contexto: A isquemia mesentérica crônica (IMC) é uma doença debilitante, com grave impacto na qualidade de vida. A literatura recomenda a angioplastia com stent da artéria mesentérica superior (AMS) como primeira opção de tratamento, mas há falta de consenso que defina indicações precisas para a revascularização aberta. Objetivos: Descrever uma série de quatro pacientes com IMC, tratados com revascularização aberta, e apresentar um algoritmo para o manejo dessa condição. Métodos: Três pacientes apresentaram angina intestinal típica e perda ponderal. Uma paciente foi submetida a reparo aberto de aneurisma da aorta abdominal e apresentava obstrução da AMS, que foi revascularizada profilaticamente. As técnicas cirúrgicas incluíram: 1) enxerto entre a aorta infrarrenal e a AMS; 2) enxerto entre o dácron utilizado em um enxerto aortobifemoral e a AMS; 3) enxerto entre a artéria ilíaca comum direita e a AMS; e 4) enxerto entre o ramo direito do dácron utilizado em um enxerto aorto-biilíaco e a artéria cólica média (ao nível da arcada de Riolan). Todos os enxertos foram feitos utilizando politetrafluoretileno em uma configuração retrógrada, tunelizados abaixo da veia renal esquerda, fazendo uma alça em C. Resultados: Todos os pacientes demonstraram resolução dos sintomas e ganho ponderal. Todos os enxertos se mantiveram pérvios durante um seguimento médio de 2 anos. Conclusões: A revascularização aberta para IMC utilizando-se a alça em C é uma técnica valiosa e pode ser considerada em pacientes selecionados. O algoritmo proposto pode auxiliar na decisão terapêutica em centros quaternários.

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Abstract Background Chronic mesenteric ischemia (CMI) is a debilitating disease with a heavy burden on quality of life. Stenting of the superior mesenteric artery (SMA) is the first option for treatment, but there is a lack of consensus defining precise indications for open revascularization (OR). Objectives To describe a series of 4 patients with CMI treated with OR and to present an algorithm for the management of this condition. Methods Three patients presented with typical intestinal angina and weight loss. One patient was subjected to prophylactic revascularization during open abdominal aortic aneurysm repair. Surgical techniques included: 1) Bypass from the infrarenal aorta to the SMA; 2) Bypass from an aorto-bifemoral polyester graft to the SMA; 3) Bypass from the right iliac artery to the SMA; 4) Bypass from the right graft limb of an aorto-biiliac polyester graft to the median colic artery at Riolan's arcade. PTFE was used in all surgeries. All grafts were placed in a retrograde configuration, tunneled under the left renal vein, making a smooth C-loop. A treatment algorithm was constructed based on the institution's experience and a review of recent literature. Results All patients demonstrated resolution of symptoms and recovery of body weight. All grafts are patent after mean follow-up of two years. Conclusions Open revascularization using the C-loop configuration is a valuable technique for CMI and may be considered in selected cases. The algorithm constructed may help decision planning in other quaternary centers.

Resumo Contexto A isquemia mesentérica crônica (IMC) é uma doença debilitante, com grave impacto na qualidade de vida. A literatura recomenda a angioplastia com stent da artéria mesentérica superior (AMS) como primeira opção de tratamento, mas há falta de consenso que defina indicações precisas para a revascularização aberta. Objetivos Descrever uma série de quatro pacientes com IMC, tratados com revascularização aberta, e apresentar um algoritmo para o manejo dessa condição. Métodos Três pacientes apresentaram angina intestinal típica e perda ponderal. Uma paciente foi submetida a reparo aberto de aneurisma da aorta abdominal e apresentava obstrução da AMS, que foi revascularizada profilaticamente. As técnicas cirúrgicas incluíram: 1) enxerto entre a aorta infrarrenal e a AMS; 2) enxerto entre o dácron utilizado em um enxerto aortobifemoral e a AMS; 3) enxerto entre a artéria ilíaca comum direita e a AMS; e 4) enxerto entre o ramo direito do dácron utilizado em um enxerto aorto-biilíaco e a artéria cólica média (ao nível da arcada de Riolan). Todos os enxertos foram feitos utilizando politetrafluoretileno em uma configuração retrógrada, tunelizados abaixo da veia renal esquerda, fazendo uma alça em C. Resultados Todos os pacientes demonstraram resolução dos sintomas e ganho ponderal. Todos os enxertos se mantiveram pérvios durante um seguimento médio de 2 anos. Conclusões A revascularização aberta para IMC utilizando-se a alça em C é uma técnica valiosa e pode ser considerada em pacientes selecionados. O algoritmo proposto pode auxiliar na decisão terapêutica em centros quaternários.

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Objetivo: Identificar los patrones de distribución vascular del ángulo esplénico del colon (AEC) en la población chilena para su comparación con la literatura oriental (Fukuoka). Materiales y Métodos: Estudio descriptivo, transversal. Se caracterizó la irrigación del AEC de imágenes con protocolo Urotac realizadas en Clínica INDISA entre el año 2020 y 2021 (n = 127), clasificándolas dentro de 6 tipos descritos por Fukuoka. Se evaluaron características demográficas y comorbilidades. Las variables fueron analizadas utilizando estadística descriptiva y la significancia mediante la prueba Chi2. Resultados: Existen diferencias en los tipos irrigación del AEC entre la serie local y Fukuoka, la irrigación tipo 3 fue la que presentó mayor variación (p < 0,05). El tipo 1 es la más frecuente (34,7%), sin casos del Tipo 4. No se identificó diferencia entre los distintos tipos de irrigación con relación a las variables demográficas y comorbilidades. Discusión: Al comparar nuestra serie con la oriental se evidenció similar frecuencia en tipos 1 y 6, mayor en tipos 3 y 5, y tipos 2 y 4 con menor representación. Se identificó un mayor aporte en la irrigación del AEC por la arteria cólica izquierda (ACI) en la población estudiada (64,6%). Conclusión: Nuestra población tiene mayor participación de ACI en irrigación del AEC que orientales (64,6% vs 49,6%), los tipos más frecuentes son 1, 3 y 6, el Tipo 1 es la forma más frecuente de irrigación, similar a Fukuoka (34,7% vs 39,7%), Tipo 3 tiene mayor representación en nuestra población que en la oriental (29,9% vs 9,9%).

Objective: To identify the vascular distribution patterns of the splenic flexure of the colon (AEC) in the Chilean population for comparison with the oriental literature (Fukuoka). Methods: Descriptive, cross-sectional study. The irrigation of the AEC of images with the Urotac protocol performed at the INDISA Clinic between 2020 and 2021 (n = 127) was characterized, classifying them into 6 types described by Fukuoka. Demographic characteristics and comorbidities were evaluated. Variables were analyzed using descriptive statistics and significance using the Chi2 test. Results: There are differences in the types of irrigation of the AEC between the local series and Fukuoka, irrigation type 3 was the one that presented the greatest variation (p < 0.05). Type 1 is the most frequent (34.7%), with no cases of Type 4. No difference was identified between the different types of irrigation in relation to demographic variables and comorbidities. Discussion: When comparing our series with the eastern one, a similar frequency was found in types 1 and 6, higher in types 3 and 5, and types 2 and 4 with less representation. A greater contribution was identified in the irrigation of the AEC by the left colic artery (ICA) in the population studied (64.6%). Conclusion: Our population has a greater participation of ICA in AEC irrigation than Orientals (64.6% vs 49.6%), the most frequent types are 1, 3 and 6, Type 1 is the most frequent form of irrigation, similar to Fukuoka (34.7% vs 39.7%), Type 3 is more represented in our population than in the eastern one (29.9% vs 9.9%).

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AIMS: Animal models are essential to investigate cardiovascular pathophysiology and pharmacology, but phylogenetic diversity makes it necessary to identify the model with vasculature most similar to that of humans. METHODS AND RESULTS: In this study, we compared the mesenteric arteries of humans, pigs, rabbits and rats in terms of the i) evolutionary changes in the amino acid sequences of α1 and ß2 adrenoceptors; M1, M2, and M3 muscarinic receptors; and bradykinin (BKR) and thromboxane-prostanoid (TP) receptors, through bioinformatics tools; ii) expression of α1, ß2, M1, M3 and TP receptors in each tunica, as assessed by immunofluorescence; and iii) reactivity to receptor-dependent and independent contractile agonists and relaxants, by performing organ bath assays. Phylogenetically, pigs showed the highest degree of evolutionary closeness to humans for all receptors, and with the exception of BKR, rabbits presented the greatest evolutionary difference compared to humans, pigs and rats. The expression of the measured receptors in the three vascular tunica in pigs was most similar to that in humans. Using a one-way ANOVA to determine the differences in vascular reactivity, we found that the reactivity of pigs was the most similar to that of humans in terms of sensitivity (pD2) and maximum effect of vascular reactivity (Emax) to KCl, phenylephrine, isoproterenol and carbachol. CONCLUSIONS: The pig is a better vascular model than the rabbit or rat to extrapolate results to human mesenteric arteries. Comparative vascular studies have implications for understanding the evolutionary history of different species. TRANSLATIONAL PERSPECTIVE: The presented findings are useful for identifying an animal model with a vasculature that is similar to that of humans. This information is important to extrapolate, with greater precision, the findings in arterial pathophysiology or pharmacology from animal models to the healthy or diseased human being.

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Endothelial nitric oxide synthase (eNOS) malfunctioning has been proposed to contribute to the endothelial damage produced by cigarette. Besides eNOS, neuronal NOS (nNOS) is also expressed in most vascular tissues and plays an important role in the endothelium-dependent vascular relaxation. We hypothesize that nNOS may contribute to the endothelium dysfunction produced by cigarette in smokers. Vascular function was assessed in human resistance mesenteric arteries using a wire myograph, the level of protein expression by Western blot, eNOS and nNOS localization by immunofluorescence. Measurement of NO was assessed by fluorescence microscopy. Arteries of smokers showed impaired endothelium-dependent vascular relaxation in response to acetylcholine. Pharmacological nonselective blockade of NOS with l-NAME and selective nNOS blockade with inhibitor 1 reduced the relaxation of the mesenteric artery of both smokers and nonsmokers. Interestingly, the inhibitory effect of NOS inhibitors was greater in nonsmokers than in smokers. The expression of total nNOS and eNOS and the level of phosphorylation at eNOS-pSer1177 were reduced in arteries of smokers as compared with nonsmokers. No differences between groups were observed in the expression of total COX-1, COX-2, catalase and SOD-1. Immunofluorescence analysis showed the presence of nNOS in the vascular endothelium in both groups. Acetylcholine-induced NO production was impaired in arteries from smokers as compared to nonsmokers. Selective inhibition of nNOS caused a decreased in NO production, which was greater in nonsmokers than in smokers. Our data show that a decrease in nNOS expression contributes to the endothelial dysfunction caused by cigarette smoking in human.

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Lead (Pb) exposure causes hazardous effects as hypertension and other cardiovascular diseases. We evaluated whether chronic Pb exposure alters the peripheral vascular resistance measuring the vascular reactivity of mesenteric resistance arteries in rats to identify the underlying mechanisms that are associated to the development of Pb-induced hypertension. Mesenteric resistance arteries from lead-treated and untreated Wistar rats (1st dose: 10 µg/100 g; subsequent doses: 0.125 µg/100 g, intramuscular, 30 days) were used. Contractile responses to phenylephrine increased, while acetylcholine and sodium nitroprusside-induced relaxation was not affected by lead treatment. Endothelium removal and inhibition of NO synthase by L-NAME similarly enhanced the response to phenylephrine in untreated and lead-treated rats. The antioxidants apocynin and superoxide dismutase (SOD) did not affect vasoconstriction in either group. The vascular expression of cyclooxygenase-2 (COX-2) protein increased after lead exposure. The respective non-specific or specific COX-2 inhibitors indomethacin and NS398 reduced more strongly the response to phenylephrine in treated rats. Antagonists of EP1 (SC19220), TP (SQ29548), IP (CAY10441) and angiotensin II type 1 (losartan) receptors reduced vasoconstriction only in treated rats. These conclusions present further evidence that lead, even in small concentration, produces cardiovascular hazards being an environmental contaminant that account for lead-induced hypertension.

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Common sloth (Bradypus variegatus) is a mammal that belongs to the superorder Xenarthra, typical from neotropical regions, with geographic distribution from Honduras to northern Argentina. Our study aimed to describe the intestine blood supply of these Bradipodids in order to collaborate with the clinical-surgical for these animals. For that, ten animals, included four females and six males, were sampled from the collection of the Anatomy Division, Department of Animal Morphology and Physiology, Universidade Federal Rural de Pernambuco DMFA/UFRPE. Corpses received formalin, preserved in saline solution and subsequently dissected for description of the cranial (AMCr) and caudal (AMC) mesenteric arteries. Sixty percent of sloths presented AMCr and AMC, cwhile 30% of them had intestines (small and large) irrigation from the common mesenteric artery (AMCo), an arterial trunk from which AMCr and AMC originated. For 10% of the specimens, the entire intestine was vascularized only by AMCr. Along the AMCr branches, there were arched arrangements, with arches size reductionat the level of the small intestine. Therefore, B. variegatus presents anatomical variations regarding the irrigation of the intestine, which can be made from AMCr and AMC, from the AMCo arterial trunk or to a lower frequency exclusively through AMCr branches.

A preguiça-comum (Bradypus variegatus)é um mamífero pertencente à superordem Xenarthra, típica de regiões neotropicais, com distribuição geográfica de Honduras ao norte da Argentina. O estudo teve como objetivo descrever o suprimento sanguíneo do intestinodestes Bradipodídeos, com o intuito de colaborar com a clínica-cirúrgica destes animais. Neste contexto, foram utilizados dez animais pertencentes ao acervo da Área de Anatomia do Departamento de Morfologia e Fisiologia Animal da Universidade Federal Rural de Pernambuco DMFA/UFRPE, sendo quatro fêmeas e seis machos. Os cadáveres foram formolizados e conservados em solução salina e, posteriormente, dissecados para a descrição das artérias mesentéricas cranial (AMCr) e caudal (AMC). Diante disto, observou-se que 60% das preguiças apresentaram AMCr e AMC.Enquanto que, em 30% delas, a irrigação dos intestinos (delgado e grosso) se deu a partir da artéria mesentérica comum (AMCo), um tronco arterial do qual se originaram AMCr e AMC. E em 10% dos espécimes, todo intestino foi vascularizado unicamente pela AMCr. Ao longo das ramificações de AMCr percebeu-se arranjos arqueados, com diminuição do tamanho dos arcos ao nível do intestino delgado. Portanto, B. variegatusapresenta variações anatômicas quanto a irrigação do intestino, podendo esta ser feita a partir de AMCr e AMC, do tronco arterial AMCo ou numa menor frequência através exclusivamente de ramos de AMCr.

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Common sloth (Bradypus variegatus) is a mammal that belongs to the superorder Xenarthra, typical from neotropical regions, with geographic distribution from Honduras to northern Argentina. Our study aimed to describe the intestine blood supply of these Bradipodids in order to collaborate with the clinical-surgical for these animals. For that, ten animals, included four females and six males, were sampled from the collection of the Anatomy Division, Department of Animal Morphology and Physiology, Universidade Federal Rural de Pernambuco DMFA/UFRPE. Corpses received formalin, preserved in saline solution and subsequently dissected for description of the cranial (AMCr) and caudal (AMC) mesenteric arteries. Sixty percent of sloths presented AMCr and AMC, cwhile 30% of them had intestines (small and large) irrigation from the common mesenteric artery (AMCo), an arterial trunk from which AMCr and AMC originated. For 10% of the specimens, the entire intestine was vascularized only by AMCr. Along the AMCr branches, there were arched arrangements, with arches size reductionat the level of the small intestine. Therefore, B. variegatus presents anatomical variations regarding the irrigation of the intestine, which can be made from AMCr and AMC, from the AMCo arterial trunk or to a lower frequency exclusively through AMCr branches.(AU)

A preguiça-comum (Bradypus variegatus)é um mamífero pertencente à superordem Xenarthra, típica de regiões neotropicais, com distribuição geográfica de Honduras ao norte da Argentina. O estudo teve como objetivo descrever o suprimento sanguíneo do intestinodestes Bradipodídeos, com o intuito de colaborar com a clínica-cirúrgica destes animais. Neste contexto, foram utilizados dez animais pertencentes ao acervo da Área de Anatomia do Departamento de Morfologia e Fisiologia Animal da Universidade Federal Rural de Pernambuco DMFA/UFRPE, sendo quatro fêmeas e seis machos. Os cadáveres foram formolizados e conservados em solução salina e, posteriormente, dissecados para a descrição das artérias mesentéricas cranial (AMCr) e caudal (AMC). Diante disto, observou-se que 60% das preguiças apresentaram AMCr e AMC.Enquanto que, em 30% delas, a irrigação dos intestinos (delgado e grosso) se deu a partir da artéria mesentérica comum (AMCo), um tronco arterial do qual se originaram AMCr e AMC. E em 10% dos espécimes, todo intestino foi vascularizado unicamente pela AMCr. Ao longo das ramificações de AMCr percebeu-se arranjos arqueados, com diminuição do tamanho dos arcos ao nível do intestino delgado. Portanto, B. variegatusapresenta variações anatômicas quanto a irrigação do intestino, podendo esta ser feita a partir de AMCr e AMC, do tronco arterial AMCo ou numa menor frequência através exclusivamente de ramos de AMCr.(AU)

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AIMS: Caffeine is a methylxanthine with multiple actions in vascular smooth muscle cells (VSMCs), including the increase in the intracellular Ca2+ (iCa2+) concentration by the activation of ryanodine receptors (RyRs). The present study aimed at investigating the participation of Ca2+-influx through different Ca2+-channels on the transient contraction (TC) induced by caffeine in mice mesenteric arteries. MAIN METHODS: Second-order of mesenteric arteries was isolated from male Swiss mice. Vessels without functional endothelium were stimulated with caffeine (10 mM). The caffeine-induced TC was evaluated after the incubation of artery rings for 30 min with the following drugs: nifedipine (10 µM), a Cav1.2 blocker; 2-aminoethoxydiphenyl borate (2-APB; 10 µM) and ruthenium red (RuR; 10 µM), transient receptor potential (TRPs) channels blockers; capsazepine (10 µM) and HC067047 (10 µM), TRPV1 and TRPV4 antagonists, respectively; paxilline (1 µM), a selective BKCa blocker; and SKF-96365 (30 µM), an Orai blocker. Ca2+-fluorescence measurements were also performed on the investigated arteries. KEY FINDINGS: The TC induced by caffeine was partially dependent on Ca2+-influx. However, the blockage of Cav1.2 increased the TC while reduced the iCa2+ signal. Similar results were observed after the blockage of TRPs or BKCa. Therefore, caffeine promoted Ca2+-influx via TRPs and Cav1.2, and hyperpolarization through the activation of BKCa, inducing negative feedback of TC. SIGNIFICANCE: Our results indicate an alternative mechanism for the control of VSMCs contraction in resistance arteries. The evidence of the negative feedback of contraction via TRP-Cav1.2-BKCa provides a new perspective for understanding the mechanism involved in the vascular responses triggered by caffeine.

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A redução da reatividade vascular à fenilefrina (PE) em aorta de ratas espontaneamente hipertensas (SHR) ao final da prenhez é dependente de maior produção e/ou maior biodisponibilidade de óxido nítrico (NO), consequente do aumento da fosforilação da enzima óxido nítrico sintase endotelial (eNOS) via PI3K/Akt. A glicosilação do tipo N-acetil-glucosamina (O-GlcNAc) é uma modificação pós-traducional que compete com a fosforilação pelos mesmos sítios de ligação nas proteínas. A O-GlcNAcilação da eNOS em serina1177 leva a redução da sua atividade enquanto a fosforilação leva a sua ativação. Além destes mecanismos, a interação da eNOS com outras proteínas é capaz de regular positiva ou negativamente a sua atividade. O objetivo deste trabalho foi analisar possíveis alterações nos mecanismos de modificação pós-traducional que controlam a ativação da eNOS os quais poderiam contribuir para maior ativação e maior biodisponibilidade de NO observada em artérias de ratas prenhes. Foram avaliados o conteúdo proteico O-GlcNAc e também expressão das enzimas que participam desta modificação, O-GlcNAc transferase (OGT) e O-GlcNAcase (OGA) por Western Blotting e a atividade da OGA por ensaio bioquímico em aorta e em artéria mesentérica (2º ou 3º ramo) de ratas não prenhes (NP) e prenhes (P), normotensas (Wistar) e SHR. Ensaios de Western Blotting foram realizados também para análise da expressão das seguintes proteínas: Cav-1, p-Cav-1, CaM e Hsp90. Realizamos a contagem do número de cavéolas endoteliais da aorta e da artéria mesentérica na presença ou ausência da metil-ß-ciclodextrina (dextrina, 10 mmol/L) por microscopia eletrônica. Em estudos funcionais, avaliamos a participação da enzima OGA, pela inibição com PugNAc (100 µmol/L) e das cavéolas, utilizando um desorganizador de cavéolas, a dextrina (10 ou 20 mmol/L), na menor reatividade vascular à PE observada em aortas de ratas P. Observamos que o conteúdo de proteínas O-GlcNAciladas estava diminuído em aorta e em leito mesentérico de ratas Wistar P e SHR P. Apesar da expressão da OGT e da OGA não estar alterada, a atividade da OGA foi aumentada em aorta e leito mesentérico de ratas Wistar P, mas, encontra-se diminuída em aorta e aumentada em leito mesentérico de SHP P. A incubação com PugNAc reverteu a reduzida reatividade à PE em aorta e artéria mesentérica de ratas Wistar P mas este efeito não foi observado em vasos SHR P, demonstrando que a OGA parece ter um papel importante na redução da O-GlcNAcilação de proteínas vasculares em Wistar P. Em vasos incubados com PugNAc, a remoção do endotélio ou a incubação com L-NAME, não alterou significativamente a reatividade à PE. Juntos estes resultados sugerem que a maior atividade da eNOS observada em vasos de Wistar P, fica prejudicada na presença do PugNAc, e depende da atividade da OGA. Como não houve alteração da resposta contrátil à PE em vasos de SHR P incubados com PugNAc, possivelmente um mecanismo diferente, envolvendo a menor atividade da OGT, ocorre nestas artérias para a redução da O-GlcNAcilação da eNOS. A desorganização das cavéolas por meio da dextrina causou aumento de contração à PE e redução de potência da ACh em aortas de Wistar NP e SHR NP, porém não houve alteração em aortas de ratas Wistar P e SHR P. A dextrina não alterou o número de cavéolas em artérias de Wistar P e SHR P quando comparado com ratas NP. SHR NP apresentam um reduzido número de cavéolas das aortas em relação a Wistar NP bem como expressão reduzida de Cav-1, p-Cav-1 e CaM. A prenhez não foi capaz de alterar a expressão da Cav-1, CaM e Hsp90 em aorta e leito mesentérico de ratas normotensas e hipertensas. Estes resultados sugerem que a prenhez não altera a expressão das proteínas Cav-1, CaM e Hsp90 e possivelmente a interação com a eNOS em aorta e artérias mesentéricas de ratas normotensas e hipertensas. Em conclusão, entre os mecanismos estudados de modificação pós-traducional da eNOS, a redução da O-GlcNAcilação da eNOS, por mecanismos que envolvem a atividade da OGA e possivelmente da OGT, favoreceria a fosforilação da eNOS e consequente maior biodisponibilidade de NO, contribuindo desta forma para modulação da resposta contrátil da PE nas artérias de ratas P(AU)

Reduction of vascular reactivity to phenylephrine (PE) in aorta of spontaneously hypertensive rats (SHR) at the end of pregnancy is dependent on higher production and/or higer bioavailability of nitric oxide (NO), as a consequence of increased endothelial nitric oxide synthase enzyme (eNOS) phosphorylation, by PI3K/Akt. Glycosylation with O-linked N-acetylglucosamine (O-GlcNAc) is a post-translational modification that competes with phosphorylation by the same binding sites in proteins. O-GlcNAcylation of eNOS on serine site leads to a reduction in its activity while eNOS phosphorylation leads to its activation. In addition to these mechanisms, the interaction of eNOS with other proteins is able to regulate positively or negatively its activity. The objective of this study was to analyze possible changes in the mechanisms of post-translational modification that control the eNOS activation, which could contribute to its the greater activation and greater bioavailability of NO observed in arteries of pregnant rats. The O-GlcNAc-protein content and also the enzymes expression that participate in this modification, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) was assessed by Western Blotting, and OGA activity were evaluated by biochemical assay in the aorta and in the artery mesenteric (2nd or 3rd branch) of non-pregnant (NP) and pregnant (P), normotensive rats (Wistar) and SHR. Western Blotting assays were also performed for expression analysis of the following proteins: Cav-1, p-Cav-1, CaM and Hsp90. We performed the counting of the number of endothelial caveolae in the aorta and the mesenteric artery in the presence or absence of methyl-ß-cyclodextrin (dextrin, 10 mmol/L) by electronic microscopy. In functional studies, we evaluated the participation of the OGA enzyme, by inhibition with PugNAc (100 µmol/L) and of the caveolae, using a caveolae disassembler, dextrin (10 or 20 mmol/L), in the reduced vascular reactivity observed in aortas or mesenteric arteries of P rats. We observed that the content of O-GlcNAcylated proteins was decreased in the aorta and in the mesenteric bed of Wistar P and SHR P rats. Although OGT and OGA expression is not altered, OGA activity was increased in the aorta and mesenteric bed of Wistar P rats but was decreased in the aorta and increased in the mesenteric bed of SHP P. Incubation with PugNAc reversed the reduced reactivity to PE in the aorta and mesenteric artery of Wistar P but this effect was not observed in SHR P arteries, demonstrating that OGA appears to play an important role in reducing O-GlcNAcylation of vascular proteins in Wistar P. In arteries incubated with PugNAc, endothelial removal or incubation with L-NAME did not significantly alter reactivity to PE. Together, these results suggest that the greater eNOS activity observed in Wistar P vessels was impaired in the presence of PugNAc, and it depends on OGA activity. As there was no change in the contractile response to PE in SHR P arteries incubated with PugNAc, possibly a different mechanism, involving the lower activity of OGT, occurs in these vessels for the reduction of O-GlcNAcylation of eNOS. Dextrin caused increased contraction of PE and decreased ACh potency in Wistar NP and SHR NP aortas, but there was no change in aortas of Wistar P and SHR P. Dextrin did not alter the number of cavelae in Wistar P and SHR P arteries compared to NP rats. SHR NP showed a lower number of caveolae than to NP Wistar as well reduced expression of Cav-1 and CaM. Pregnancy was not able to alter the expression of Cav-1, CaM and Hsp90 in the aorta and mesenteric bed of normotensive and hypertensive rats. These results suggest that pregnancy does not alter the expression of Cav-1, CaM and Hsp90 proteins and possibly interaction with eNOS in the aorta and mesenteric arteries of normotensive and hypertensive rats. In conclusion, among the studied mechanisms of post-translational modification of eNOS, the reduction of O-GlcNAcylation of eNOS, by mechanisms that involve OGA activity and possibly OGT, would favor eNOS phosphorylation and consequent greater NO bioavailability, contributing in this way for modulation of the contractile response to PE in the arteries of P rats(AU)

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The study evaluated the vasorelaxant effect induced by the ethanolic extract of the leaves of Zanthoxylum rhoifolium Lam (EEtOH-Zr/leaves). Wistar rats were treated with the leaf extract containing a single dose of 2,000 mg / kg, v.o. After 14 days, the animals were anesthetized for blood collection and subsequent analysis of the biochemical parameters; they were then euthanized (sodium pentobarbital-100 mg/kg, i.p.) for the removal and morphological analysis of the heart, lung, liver and kidney. The vasorelaxation activity the and vascular reactivity of EEtOH-Zr/leaves were evaluated on artery mesenteric rings isolated from rats. The extract showed no signs of toxicity and no significant difference in the values of the biochemical parameters between the control group and the group of treated animals. In the evaluation of pharmacological activity in the smooth muscle, the EEtOH-Zr/leaves caused vasorelaxant effect on the tonic contraction induced by phenylephrine in mesenteric artery preparations in the presence (pD2=2.17±0.05 µg/mL; Emax=99.8±5.2%) and absence (pD2=2.14±0.05 µg/mL; Emax=95.3±6.4%) of the vascular endothelium. Oral administration of EEtOH-Zr/leaves reduced the contraction induced by the cumulative addition of PHE. It is concluded that the EEtOH-Zr/leaves promote vasorelaxation and reduce vascular reactivity of adrenergic alpha-1 agonist in the mesenteric artery. The results did not show toxic effects of the extract.

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Neuronal nitric oxide synthase (nNOS) is expressed in the cardiovascular system and besides NO, generates H2O2. nNOS has been proposed to contribute to the control of blood pressure in healthy humans. The aim of this study was to verify the hypothesis that nNOS can contribute to the control of vascular relaxation and blood pressure in hypertensive patients undergoing drug treatment. The study was conducted in resistance mesenteric arteries from 63 individuals, as follows: 1) normotensive patients; 2) controlled hypertensive patients (patients on antihypertensive treatment with blood pressure normalized); 3) uncontrolled hypertensive patients (patients on antihypertensive treatment that remained hypertensive). Only mesenteric arteries from uncontrolled hypertensive patients showed impaired endothelium-dependent vasorelaxation in response to acetylcholine (ACh). Selective nNOS blockade with inhibitor 1 and catalase, which decomposes H2O2, decreased vasorelaxation in the three groups. However, the inhibitory effect was greater in controlled hypertensive patients. Decreased eNOS expression was detected in both uncontrolled and controlled hypertensive groups. Interestingly nNOS expression and ACh-stimulated H2O2 production were greater in controlled hypertensive patients, than in the other groups. ACh-stimulated NO production was lower in controlled hypertensive when compared to normotensive patients, while uncontrolled hypertensive patients showed the lowest levels. Catalase and nNOS blockade inhibited ACh-induced H2O2 production. In conclusion, nNOS-derived H2O2 contributes to the endothelium-dependent vascular relaxation in human resistance mesenteric arteries. The endothelial dysfunction observed in uncontrolled hypertensive patients involves decreased eNOS expression and NO production. The normalization of vascular relaxation and blood pressure in controlled hypertensive patients involves increased nNOS-derived H2O2 and NO production.

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As artérias mesentéricas das aves são importantes para a irrigação do aparelho digestório e encontram-se associadas ao ganho de peso e conversão alimentar. Objetivou-se descrever as origens, esqueletopias, medidas e principais ramificações das artérias mesentéricas cranial e caudal em avestruzes. Foram utilizados 41 cadáveres de filhotes de avestruzes, 23 machos e 18 fêmeas, obtidos de um criadouro após morte natural. Os cadáveres foram fixados com formaldeído a 10% e tiveram o sistema vascular preenchido com Petrolatex® S-65 colorido. As artérias mesentéricas, cranial e caudal e seus ramos proximais foram dissecados "in situ" e medidas com paquímetro digital. A artéria mesentérica cranial teve comprimento médio de 3,68 ± 1,04 cm e surgiu da aorta descendente ao nível da oitava vértebra torácica na maioria dos casos. Ramificou-se em artérias jejunal e ileocecal. A artéria jejunal ofereceu média de 14,04 ±2,08 ramos ao jejuno e a artéria ileocecal originou um ramo retal e outro que se bifurcou para derivar ramos para íleo, ceco e reto. Em um espécime macho a artéria ileocecal foi ramo da artéria celíaca. A artéria mesentérica caudal originou-se na porção terminal da aorta descendente predominantemente ao nível das 4ª e 6ª vértebras sacro-caudais. Perto da extremidade caudal do rim emitiu os ramos cranial e caudal. O primeiro irrigou o reto e anastomosou-se com ramo retal da artéria mesentérica cranial; o segundo irrigou a porção final do reto, cloaca e bolsa cloacal. Não houve diferença significativa (p<0,05) entre as medidas, esqueletopia e número de ramificações das artérias entre os sexos.(AU)

The mesenteric arteries of birds are important for the irrigation of the digestive tract and are associated with weight gain and food conversion. This study aimed to describe the origins, skeletopy, measures and main branches of cranial and caudal mesenteric arteries in ostriches. Forty-one cadavers of ostrich chicks, 23 males and 18 females, obtained from a farmer after natural death. The cadavers were fixed with 10% formaldehyde solution and their vascular system was filled with colored Petrolatex® S-65. The cranial and caudal mesenteric arteries and its proximal branches were dissected in situ and measured with a digital caliper. The mesenteric artery had an average length of 3.68cm±1.04 and emerged from the descending aorta at the level of the eighth thoracic vertebra in most cases; it branched into jejunal and ileocecal arteries. The jejunal artery sent a mean of 14 (14.04±2.08) branches to the jejunum. The ileocecal artery sent a rectal branch and another branch that irrigated ileum, cecum and rectum. In a male specimen the ileocecal artery was originated from the celiac artery. The caudal mesenteric artery emerged in the terminal portion of the descending aorta predominantly at the level of the 4th and 6th sacrocaudal vertebrae. Near the caudal end of the kidney it issued the cranial and caudal branches. The first irrigated the rectum and anastomosed with the rectal branch of the cranial mesenteric artery; the second irrigated the final part of the rectum, cloaca and cloacal bursa. There was no significant difference (p<0.05) between measurements, skeletopy and number of branches of the arteries between genders.(AU)

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The mesenteric arteries of birds are important for the irrigation of the digestive tract and are associated with weight gain and food conversion. This study aimed to describe the origins, skeletopy, measures and main branches of cranial and caudal mesenteric arteries in ostriches. Forty-one cadavers of ostrich chicks, 23 males and 18 females, obtained from a farmer after natural death. The cadavers were fixed with 10% formaldehyde solution and their vascular system was filled with colored Petrolatex® S-65. The cranial and caudal mesenteric arteries and its proximal branches were dissected in situ and measured with a digital caliper. The mesenteric artery had an average length of 3.68 cm±1.04 and emerged from the descending aorta at the level of the eighth thoracic vertebra in most cases; it branched into jejunal and ileocecal arteries. The jejunal artery sent a mean of 14 (14.04±2.08) branches to the jejunum. The ileocecal artery sent a rectal branch and another branch that irrigated ileum, cecum and rectum. In a male specimen the ileocecal artery was originated from the celiac artery. The caudal mesenteric artery emerged in the terminal portion of the descending aorta predominantly at the level of the 4th and 6th sacrocaudal vertebrae. Near the caudal end of the kidney it issued the cranial and caudal branches. The first irrigated the rectum and anastomosed with the rectal branch of the cranial mesenteric artery; the second irrigated the final part of the rectum, cloaca and cloacal bursa. There was no significant difference (p<0.05) between measurements, skeletopy and number of branches of the arteries between genders.(AU)

As artérias mesentéricas das aves são importantes para a irrigação do aparelho digestório e encontram-se associadas ao ganho de peso e conversão alimentar. Objetivou-se descrever as origens, esqueletopias, medidas e principais ramificações das artérias mesentéricas cranial e caudal em avestruzes. Foram utilizados 41 cadáveres de filhotes de avestruzes, 23 machos e 18 fêmeas, obtidos de um criadouro após morte natural. Os cadáveres foram fixados com formaldeído a 10% e tiveram o sistema vascular preenchido com Petrolatex® S-65 colorido. As artérias mesentéricas, cranial e caudal e seus ramos proximais foram dissecados "in situ" e medidas com paquímetro digital. A artéria mesentérica cranial teve comprimento médio de 3,68 ± 1,04 cm e surgiu da aorta descendente ao nível da oitava vértebra torácica na maioria dos casos. Ramificou-se em artérias jejunal e ileocecal. A artéria jejunal ofereceu média de 14,04 ±2,08 ramos ao jejuno e a artéria ileocecal originou um ramo retal e outro que se bifurcou para derivar ramos para íleo, ceco e reto. Em um espécime macho a artéria ileocecal foi ramo da artéria celíaca. A artéria mesentérica caudal originou-se na porção terminal da aorta descendente predominantemente ao nível das 4ª e 6ª vértebras sacro-caudais. Perto da extremidade caudal do rim emitiu os ramos cranial e caudal. O primeiro irrigou o reto e anastomosou-se com ramo retal da artéria mesentérica cranial; o segundo irrigou a porção final do reto, cloaca e bolsa cloacal. Não houve diferença significativa (p < 0,05) entre as medidas, esqueletopia e número de ramificações das artérias entre os sexos.(AU)

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O TERPY promove efeito hipotensor de maior magnitude em ratos hipertensos (SHR e 2R-1C) do que em ratos normotensos (Wistar e 2R). Foi demonstrado anteriormente que o endotélio prejudica o efeito vasodilatador do TERPY em aorta de Wistar. No entanto, observamos que o endotélio melhora os efeitos vasodilatadores do TERPY em aorta de SHR. Vasos sanguíneos de menor calibre, tais como as artérias de resistência, estão associadas ao controle da resitência vascular periférica e da pressão arterial. Nossa hipótese é que o TERPY induz relaxamento nas artérias mesentéricas de resistência em SHR e que as células endoteliais modulam positivamente o efeito do TERPY nestes vasos sanguíneos. Portanto, o nosso objetivo foi avaliar o efeito vasodilatador do TERPY em anéis com e sem endotélio de artéria mesentérica de ratos SHR, o seu mecanismo de relaxamento e a participação da NOS sobre esse efeito. e a Nossos resultados mostraram que o TERPY induziu um efeito vasodilatador dependente da concentração em anéis de artérias mesentéricas (2º e 3º ramos) de SHR e de ratos Wistar. A potência do TERPY foi maior em anéis intactos do que em anéis sem endotélio em artérias mesentéricas de SHR, mas em Wistar o endotélio prejudicou o efeito do TERPY. Nas artérias mesentéricas sem endotélio de SHR, o efeito do TERPY é dependente da atividade da guanilato ciclase solúvel e de canais para potássio. Nas artérias mesentéricas intactas de SHR, o efeito de TERPY depende da atividade de eNOS, mas não é dependente das atividades de nNOS, iNOS ou da via da ciclooxigenase. O TERPY promove a fosforilação da eNOS nos resíduos de serina1177 e aumenta a concentração de óxido nítrico em células endoteliais isoladas de artérias mesentéricas de SHR. Nossos resultados mostraram que a guanilato ciclase solúvel, os canais para potássio e a eNOS estão envolvidos no efeito vasodilatador estimulado pelo TERPY nas artérias de resistência mesentérica de SHR. Numa segunda parte deste estudo, avaliamos o mecanismo de ação de TERPY e seu efeito sobre a atividade da eNOS em células endoteliais. As células HUVEC, WT-HEK e HEK-eNOS foram tratadas com TERPY em diferentes tempos (0 a 60 minutos). Foram analisados por Western blotting o efeito do TERPY sobre a fosforilação de eNOS, monômero e dímero da eNOS e sobre monômero e oligômero de caveolina-1. Também foi avaliado o efeito do TERPY na interação eNOS/Cav-1 através de co-imunoprecipitação. As alterações induzidas pelo TERPY sobre as concentrações de espécies reativas de oxigênio e peroxinitrito em células endoteliais foram medidas usando sonda DHE e biossensor 7-CBA, respectivamente. A concentração de óxido nítrico (NO) foi avaliada por sonda DAF-FM e sensor Cooper. O TERPY promoveu desacoplamento e disfunção da eNOS, dependente de BH4. A desestabilização dos oligômeros da caveolina-1 foi induzida pelo TERPY. Consequentemente, o TERPY reduziu a interação eNOS/Cav-1 e promoveu ativação da eNOS. Nossos resultados mostraram que a atividade da eNOS pode ser regulada de duas maneiras diferentes pelo TERPY. O TERPY promove desacoplamento e fosforilação da eNOS, promovendo uma estratégia diferente para a regulação da atividade desta enzima. As moléculas químicas ou biológicas como o TERPY que regulam a atividade da eNOS e aumentam a produção e a biodisponibilidade de NO teriam ações terapêuticas importantes para o tratamento de doenças vasculares associadas a hipertensão(AU)

TERPY promotes a hypotensive effect with greater magnitude in hypertensive rats (SHR and 2K-1C) than in normotensive rats (Wistar and 2K). Previously, it was demonstrated that endothelium impairs vasodilatory effect of TERPY in Wistar aorta. However, we observed that endothelium improves the vasodilatory effect of TERPY in SHR aorta. Smaller blood vessels, such as mesenteric arteries, are associated with the control of peripheral vascular resistance and blood pressure. We hypothesized that TERPY induces relaxation on mesenteric resistance arteries in SHR and endothelial cells modulate positively the TERPY's effect on these blood vessels. Therefore, our goal was to evaluate the vasodilator effect of TERPY in rings with and without endothelium of mesenteric arteries in SHR, the mechanism of relaxation and the participation of NOS on this effect. Our results show TERPY induced a concentration-dependent vasodilator effect in mesenteric arteries (2nd and 3 rd branches) rings from SHR and Wistar. The potency of TERPY was higher in intact than in denuded rings from SHR, but in Wistar, endothelium impair the TERPY's effect. In denuded mesenteric arteries from SHR, the relaxation effect induced by TERPY is dependent of soluble guanylate cyclase and activation of potassium channel. However, in intact mesenteric arteries from SHR, TERPY´s effect is modulated by eNOS activity, but it is not dependent of nNOS, iNOS or cyclooxygenase pathway activities. TERPY promotes eNOS3 Ser1177 phosphorylation and increases nitric oxide concentration in isolated endothelial cells of mesenteric arteries from SHR. Together, our results showed that soluble guanylate cyclase, potassium channels, and eNOS are involved in the vasodilator effect of TERPY in mesenteric resistance arteries from SHR. In a second part of this study, we aimed to evaluate the mechanism of action of TERPY and its effect on eNOS activity in endothelial cells. HUVEC, WT-HEK and HEK-eNOS cells were treated with TERPY at different times (0 to 60 minutes). Were analyzed by western blotting the TERPY`s effect on eNOS monomer, dimer and phosphorylation and on monomer and oligomer of caveolin-1. It was also evaluated the effect of TERPY in the interaction between eNOS/Cav-1 through co-immunoprecipitation. Alterations induced by TERPY on reactive oxygen species and peroxynitrite concentrations in endothelial cells were measured by using DHE probe and biosensor 7-CBA, respectively. Nitric oxide fluorescence was assessed by DAF-FM probe and Cooper sensor. TERPY promoted eNOS uncoupling and eNOS dysfunction, which is BH4-dependent. Caveolin-1 oligomers destabilization was induced by TERPY. Consequently, TERPY reduced eNOS/Cav-1 interaction and promoted eNOS activation. Our results show that eNOS activity can be regulated in two different ways by TERPY, leading to eNOS uncoupling and leading to eNOS phosphorylation, promoting a strategy for eNOS regulation. Chemical or biological molecules as TERPY that regulates eNOS activity and increase NO production and bioavailability are potential therapeutic drugs for the treatment of vascular diseases associated with hypertension(AU)

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Background: The yellow-toothed cavy is a wild rodent in the Caviidae family. It adapts well to captivity and may, in thenear future, be bred on a large scale as an alternative source of low cost protein of high nutritional value. Considering thelack of information available on the vascularization of this species digestive system, and with the aim of contributing tothe body of knowledge of this species biology, this study describes the origin and distribution of the cranial and caudalmesenteric arteries of the yellow-toothed cavy.Materials, Methods & Results: Twenty male yellow-toothed cavies, previously used in other experiments (CEUA N.15/2014 and Process N° 23.091.000653/2014-26), were kept in a freezer at the Center for the Multiplication of WildAnimals (CEMAS / UFERSA). The animals were thawed, after which the thoracic aorta of each specimen was caudallycannulated and injected with red- or yellow-colored latex solution. The animals were then fixed in 10% formaldehydesolution, and dissected after 48 h, during which the branches of the cranial and caudal mesenteric arteries were described.In all cases, the cranial mesenteric artery arised from the section of abdominal aorta, at the section between the first andsecond lumbar vertebra, near the celiac artery, and it includes the following arterial branches: the caudal pancreatic duodenal, middle colic, duodenojejunal and right colic arteries, as well as eight to eleven jejune arteries, and the ileocecocolictrunk, from which extend one or two colic branches, five to seven cecum branches, and the ileal artery. In all animals, thecranial mesenteric artery originates from the abdominal aorta, posterior to the testicular arteries...(AU)

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Background: The yellow-toothed cavy is a wild rodent in the Caviidae family. It adapts well to captivity and may, in thenear future, be bred on a large scale as an alternative source of low cost protein of high nutritional value. Considering thelack of information available on the vascularization of this species’ digestive system, and with the aim of contributing tothe body of knowledge of this species’ biology, this study describes the origin and distribution of the cranial and caudalmesenteric arteries of the yellow-toothed cavy.Materials, Methods & Results: Twenty male yellow-toothed cavies, previously used in other experiments (CEUA N.15/2014 and Process N° 23.091.000653/2014-26), were kept in a freezer at the Center for the Multiplication of WildAnimals (CEMAS / UFERSA). The animals were thawed, after which the thoracic aorta of each specimen was caudallycannulated and injected with red- or yellow-colored latex solution. The animals were then fixed in 10% formaldehydesolution, and dissected after 48 h, during which the branches of the cranial and caudal mesenteric arteries were described.In all cases, the cranial mesenteric artery arised from the section of abdominal aorta, at the section between the first andsecond lumbar vertebra, near the celiac artery, and it includes the following arterial branches: the caudal pancreatic duodenal, middle colic, duodenojejunal and right colic arteries, as well as eight to eleven jejune arteries, and the ileocecocolictrunk, from which extend one or two colic branches, five to seven cecum branches, and the ileal artery. In all animals, thecranial mesenteric artery originates from the abdominal aorta, posterior to the testicular arteries...

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The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: Km (r = 0.612, P = 0.034) and Vmax (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: Km (r = -0.625, P = 0.029) and Vmax (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress.

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Objetivo: investigar experimentalmente o suprimento arterial do colo descendente e reto, após ligadura da artéria mesentérica caudal, pela análise da viabilidade da arcada paracólica suprida pela persistência da irrigação do colo descendente. Métodos: foram estudados 30 animais separados em três grupos para observação pós-operatória de 24, 48 e 72 horas. Realizaram-se laparotomia, ligadura da artéria mesentérica caudal e dos vasos retais médios, ligadura do pedículo vascular retal inferior, amputação do reto e posterior colostomia perineal. Foi realizada relaparotomia após o período de observação, com identificação da mesma região. Os cães foram, então, mortos, sendo retirados três pequenos segmentos: um a 10 cm e dois a 10 cm acima e abaixo do linfonodo mesentérico caudal, respectivamente. Resultados: no grupo de animais observados com 72 horas de pós-operatório, abaixo do linfonodo, houve viabilidade estatisticamente significativa, tendo ocorrido necrose estatisticamente significativa nos grupos de 24 e 48 horas. Conclusão: a viabilidade do cólon e do reto cranial depende de anastomose entre os territórios da mesentérica cranial e caudal, mas essa comunicação não está presente em todos os animais.

Objective: experimentally investigate the arterial supply of the descending colon and rectum after ligation of the caudal mesenteric artery, by examining the viability of the paracolic arcade supplied by the persistent irrigation of the descending colon. Methods: 30 animals separated into three groups for 24, 48 and 72 hours posoperatory observation were under study. Laparotomy, ligation of the caudal mesenteric artery and middle rectal vessels, ligation of the inferior rectal vascular pedicle, amputation of lhe rectum and posterior perineal colostomy were performed. Then the dogs were killed, and three small segments were removed: one at 10 cm and two others at 10 cm above and below the caudal mesenteric lymph nodes, respectively. Results: in the group of animals observed with 72 hours posoperatory, there was statistically significant viability below the limph node,with statistically significant necrosis in the 24 and 48 hour groups. Conclusions: the viability of colon and rectal cranial depends on the anastomosis between the territories of the cranial and caudal mesentric, but this communication is not found in all the animals.

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