Inhibition of Thrombin in Cardiac Surgery : experiments in a porcine model

Cardiac surgery involving cardiopulmonary bypass (CPB) induces activation of inflammation and coagulation systems and is associated with ischemia-reperfusion injury (I/R injury)in various organs including the myocardium, lungs, and intestine. I/R injury is manifested as organ dysfunction. Thrombin, the key enzyme of coagulation , plays a cenral role also in inflammation and contributes to regulation of apoptosis as well. The general aim of this thesis was to evaluate the potential of thrombin inhibition in reducing the adverse effects of I/R injury in myocardium, lungs, and intestine associated with the use of CPB and cardiac surgery. Forty five pigs were used for the studies. Two randomized blinded studies were performed. Animals underwent 75 min of normothermic CPB, 60 min of aortic clamping, and 120 min of reperfusion period. Twenty animals received iv. recombinant hirudin, a selective and effective inbitor of thrombin, or placebo. In a similar setting, twenty animals received an iv-bolus (250 IU/kg) of antithrombin (AT) or placebo. An additional group of 5 animals received 500 IU/kg in an open label setting to test dose response. Generation of thrombin (TAT), coagulation status (ACT), and hemodynamics were measured. Intramucosal pH and pCO2 were measured from the luminal surface of ileum using tonometry simultaneusly with arterial gas analysis. In addition, myocardial, lung, and intestinal biopsies were taken to quantitate leukocyte infiltration (MPO), for histological evaluation, and detection of apoptosis (TUNEL, caspase 3). In conclusion, our data suggest that r-hirudin may be an effective inhibitor of reperfusion induced thrombin generation in addition to being a direct inhibitor of preformed thrombin. Overall, the results suggest that inhibition of thrombin, beyond what is needed for efficient anticoagulation by heparin, has beneficial effects on myocardial I/R injury and hemodynamics during cardiac surgery and CPB. We showed that infusion of the thrombin inhibitor r-hirudin during reperfusion was associated with attenuated post ischemia left ventricular dysfunction and decreased systemic vascular resistance. Consequently microvascular flow was improved during ischemia-reperfusion injury. Improved recovery of myocardium during the post-ischemic reperfusion period was associated with significantly less cardiomyocyte apoptosis and with a trend in anti-inflammatory effects. Thus, inhibition of reperfusion induced thrombin may offer beneficial effects by mechanisms other than direct anticoagulant effects. AT, in doses with a significant anticoagulant effect, did not alleviate myocardial I/R injury in terms of myocardial recovery, histological inflammatory changes or post-ischemic troponin T release. Instead, AT attenuated reperfusion induced increase in pulmonary pressure after CPB. Taken the clinical significance of postoperative pulmonary hemodynamics in patients undergoing cardiopulmonary bypass, the potential positive regulatory role of AT and clinical implications needs to be studied further. Inflammatory response in the gut wall proved to be poorly associated with perturbed mucosal perfusion and the animals with the least neutrophil tissue sequestration and I/R related histological alterations tended to have the most progressive mucosal hypoperfusion. Thus, mechanisms of low-flow reperfusion injury during CPB can differ from the mechanisms seen in total ischemia reperfusion injury.

Fatty acid specificity for the esterification of vitamin A and cholesterol by intestinal and pancreatic enzymes in rats

VITAMIN A and cholesterol esters have been shown to undergo extensive hydrolysis in the lumen of the small intestine during the process of absorption; they are re-esterified to appear in the lymph mostly as esters1,2. However, the vitamin A esters of the lymph, blood and liver of the rat are formed by long-chain fatty acids3 and in the normal rat liver, probably as palmitates4. On the other hand, cholesterol esters are usually made up of poly-unsaturated fatty acids in the lymph and blood of rats5. For the absorption of the two lipid materials, the enzymes of the pancreas have been largely implicated, while not much attention has been paid to the possible role of the mucosal enzymes. From the behaviour of the mucosal enzymes, as presented here, it appears that probably these enzymes play a more important part in the re-esterification of the two lipid materials during their absorption.

The multiple and enigmatic roles of guanylyl cyclase C in intestinal homeostasis

Guanylyl cyclase C (GC-C) is predominantly expressed in intestinal epithelial cells and serves as the receptor for the gastrointestinal hormones guanylin and uroguanylin, and the heat-stable enterotoxin, the causative agent for Travellers' Diarrhea. Activation of GC-C results in an increase in intracellular levels of cGMP, which can regulate fluid and ion secretion, colon cell proliferation, and the gut immune system. This review highlights recent findings arising from studies in the GC-C knockout mouse, along with enigmatic results obtained from the first descriptions of human disease caused by mutations in the GC-C gene. We provide some insight into these new findings and comment on areas of future study, which may enhance our knowledge of this evolutionarily conserved receptor and signaling system. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.

Effects of dietary supplementation of commercial human probiotic and antibiotic on the growth rate and content of intestinal microflora in ornamental fishes

The effects of dietary supplementation of commercial human probiotic, Lactobacil and antibiotic, oxytetracycline on the growth, survival, disease resistance and content of intestinal microflora in two ornamental fishes, viz., goldfish, Carassius auratus and swordtail, Xiphophorus helleri were studied. The total wet weight gain, food conversion ratio and specific growth rate of C. auratus did not vary significantly (p>0.05) among treatments. While in X. helleri, significant differences existed in the total wet weight gain, survival, food conversion ratio and specific growth rate among treatment groups (p<0.05). The counts of antibiotic resistant bacteria in fish gut increased with days of culture in all the treatments and the increase was more in antibiotic fed fishes. A reduction in the development of antibiotic resistance among the bacterial flora of fish gut was noticed in probiotic fed groups of C auratus and X. helleri. The results of the present study revealed that the effects of human probiotic on the growth, survival and disease resistance of ornamental fishes are variable and difficult to reproduce the similar effect on different species.

Effect of dietary inulin as prebiotic on growth, survival and intestinal bacterial density of juvenile great sturgeon (Huso huso)

Use of prebiotics, nondigestible dietary ingredients that beneficially affect the host by selectively stimulating the growth of and/or activating the metabolism of healthpromoting bacteria in the intestinal tract, is a novel concept in aquaculture. An 8-week feeding experiment was conducted to investigate the effects of dietary prebiotic inulin on the growth performance, intestinal bacterial density, body composition and values of blood serum enzymes in the juvenile great sturgeon (Huso huso). Three replicate groups of fish (initially averaging weight 16.14±0.38g) were fed diets containing prebiotic inulin at levels ranging from 1% to 3%. The basal diet was contained 3% cellulose. The results of linear regression showed there was a negative relationship between some performance indices including weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), net protein utilization (NPU), energy retention (ERE), feed efficincy (FE), protein retention (PR) and supplementation level of inulin. At the end of trial, the 1% inulin treatment insignificantly showed an enhaced survival between the treatment groups. Intestinal lactic acid bacteria (LAB) increased in group treated with 1% inulin compare to other groups. No significant difference were observed in body composition and level of serum enzymes (P>0.05). Moreover there was significant correlation between ALT and LDH values (P<0.01). Result obtained in this study shows that the prebiotic inulin didn’t influence the increase of the growth performance of juvenile great sturgeon and it is not appropriate for supplementation in the diet of beluga.

Changes of tissue endothelin-1 and nitric oxide synthase in a sheep model of large intestinal obstruction

Large intestinal obstruction (LIO) in farm animals can cause a ischaemic necrosis of intestinal tissue, eventually leading to death. The roles of endothelin-1 (ET-1) and nitric oxide (NO) are not well understood in the process of LIO, but evidence suggests that endothelial-derived mediators may participate. In the present study, ET-1 concentration and total nitric oxide synthase (NOS) activity were measured in heart, liver, pancreas, lung and kidney in a model of LIO in sheep. Our data demonstrated that ET-1 concentration and NOS activity were altered, with significant increases of ET-1 in heart, lung and kidney and of NOS activity in pancreas and kidney, but a marked decline of NOS activity in liver (p<0.05). It is postulated that these alterations in NOS activity and ET-1 concentration may contribute to the progressive loss of organ function, and finally lead to death in LIO in sheep.

Effects of Naotan Pill on repair of neural cells and cognitive disorders in juvenile rats following hypoxia and ischemia

BACKGROUND: Hypoxia and ischemia induce neuronal damage, decreased neuronal numbers and synaptophysin levels, and deficits in learning and memory functions. Previous studies have shown that lycium barbarum polysaccharide, the most effective component of barbary wolfberry fruit, has protective effects on neural cells in hypoxia-ischemia. OBJECTIVE: To investigate the effects of Naotan Pill on glutamate-treated neural cells and on cognitive function in juvenile rats following hypoxia-ischemia. DESIGN, TIME AND SETTING: The randomized, controlled, in vivo study was performed at the Cell Laboratory of Lanzhou University, Lanzhou Institute of Modern Physics of Chinese Academy of Sciences, and Department of Traditional Chinese Medicine of Gansu Provincial Rehabilitation Center Hospital, China from December 2005 to August 2006. The cellular neurobiology, in vitro experiment was conducted at the Institute of Human Anatomy, Histology, Embryology and Neuroscience, School of Basic Medical Sciences, Lanzhou University, and Department of Traditional Chinese Medicine of Gansu Provincial Rehabilitation Center Hospital, China from March 2007 to January 2008. MATERIALS: Naotan Pill, composed of barbary wolfberry fruit, danshen root, grassleaf sweetflag rhizome, and glossy privet fruit, was prepared by Gansu Provincial Rehabilitation Center, China. Rabbit anti-synaptophysin, choline acetyl transferase polyclonal antibody, streptavidin-biotin complex kit and diaminobenzidine kit (Boster, Wuhan, China), as well as glutamate (Hualian, Shanghai, China) were used in this study. METHODS: Cortical neural cells were isolated from neonatal Wistar rats. Neural cell damage models were induced using glutamate, and administered Naotan Pill prior to and following damage. A total of 54 juvenile Wistar rats were equally and randomly assigned into model, Naotan Pill, and sham operation groups. The left common carotid artery was ligated, and then rat models of hypoxic-ischemic injury were assigned to the model and Naotan Pill groups. At 2 days following model induction, rats in the Naotan Pill group were administered Naotan Pill suspension for 21 days. In the model and sham operation groups, rats received an equal volume of saline. MAIN OUTCOME MEASURES: Neural cell morphology was observed using an inverted phase contrast microscope. Survival rate of neural cells was measured by MTT assay. Synaptophysin and choline acetyl transferase expression was observed in the hippocampal CA1 region of juvenile rats using immunohistochemistry. Cognitive function was tested by the Morris water maze. RESULTS: Pathological changes were detected in glutamate-treated neural cells. Neural cell morphology remained normal after Naotan Pill intervention. Absorbance and survival rate of neural cells were significantly greater following Naotan Pill intervention, compared to glutamate-treated neural cells (P < 0.05). Synaptophysin and choline acetyl transferase expression was lowest in the hippocampal CA1 region in the model group and highest in the sham operation group. Significant differences among groups were observed (P < 0.05). Escape latency and swimming distance were significantly longer in the model group compared to the Naotan Pill group (P < 0.05). CONCLUSION: Naotan Pill exhibited protective and repair effects on glutamate-treated neural cells. Naotan Pill upregulated synaptophysin and choline acetyl transferase expression in the hippocampus and improved cognitive function in rats following hypoxia-ischemia.

The purification and characterization of the high and low molecular weight forms of rabbit intestinal adenosine deaminase

Accepted Version

The ELDERMET biobank: Isolation and characterization of the intestinal microbiota from elderly Irish subjects

The human gastrointestinal (GI) tract is colonized by a dense and diverse bacterial community, the commensal microbiota, which plays an important role in the overall health of individuals. This microbiota is relatively stable throughout adult life, but may fluctuate over time with aging and disease. The adaptation of the gut microbiota to our changing life-style is probably the reason for the large inter-individual variation observed among different people. Since the gut microbiota plays an essential role in interactions with host metabolism, it is of utmost importance to explore this relationship. The elderly intestinal microbiota has been the subject of a number of studies in recent years. The results presented in this thesis have further contributed to the expansion of knowledge related to gut microbiota research highlighting the combined effect of culture based and molecular methods as powerful tools for understanding the true impact of microbes. The degree of correlation between measurements from both methods suggested that a single method is capable of profiling intestinal Bifidobacterium spp., Lactobacillus spp. and Enterobacteriaceae populations. Bacteriocins have shown great promise as alternatives to traditional antibiotics. In this respect, the isolation and characterisation of bacteriocinogenic strains are important due to growing evidence indicating bacteriocin production as a potential probiotic trait by virtue of strain dominance and/or pathogen inhibition in the mammalian intestine. The selection pressure applied on the bacterial population during antibiotic usage is the driving force for the emergence of antibiotic resistant bacteria. Identification of antibiotic resistant isolates opens up the possibility of using such probiotics to offset the problems caused by antibiotics to the gut microbiota and to improve the intestinal microbial environment. Future work is required to explore the culture collection housing thousands of bacterial isolates as a valuable source of potential probiotics for use for the elderly Irish community.

Diversion of intestinal flow decreases the numbers of interleukin 4 secreting and interferon gamma secreting T lymphocytes in small bowel mucosa.

BACKGROUND/AIMS: The intestinal immune system faces large amounts of antigens, and its regulation is tightly balanced by cytokines. In this study, the effect of intestinal flow diversion on spontaneous secretion of interleukin (IL)-4 and interferon (IFN)- gamma was analysed. METHODS: Eight patients (two with Crohn's disease, four with ulcerative colitis, and two with previous colon cancer) carrying a double lumen small bowel stoma after a total colectomy procedure were included in the study. For each patient, eight biopsy samples were taken endoscopically from both the diverted and non-diverted part of the small bowel. Intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) were isolated separately and assayed for numbers of cells spontaneously secreting IL-4 and/or IFN-gamma by an ELISPOT technique. RESULTS: Compared with the non-diverted mucosa, a significant decrease in the number of spontaneously IFN-gamma secreting CD3 lymphocytes was observed in the diverted small bowel mucosa among both IELs (p = 0.008) and LPLs (p = 0.007). The same results, although less significant, were obtained for IL-4, especially in LPLs (p = 0.01). CONCLUSION: The intestinal content influences the spontaneous secretion of IFN-gamma and IL-4 by intestinal lymphocytes. These results could help to elucidate the anti-inflammatory role of split ileostomy in patients suffering from inflammatory bowel diseases.

Receptors for secretin, helodermin, VIP (vasoactive intestinal peptide), PHI and GRF (growth hormone releasing factot) in the rat pancreas

info:eu-repo/semantics/published

Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential.

Oxidative stress has become widely viewed as an underlying condition in a number of diseases, such as ischemia-reperfusion disorders, central nervous system disorders, cardiovascular conditions, cancer, and diabetes. Thus, natural and synthetic antioxidants have been actively sought. Superoxide dismutase is a first line of defense against oxidative stress under physiological and pathological conditions. Therefore, the development of therapeutics aimed at mimicking superoxide dismutase was a natural maneuver. Metalloporphyrins, as well as Mn cyclic polyamines, Mn salen derivatives and nitroxides were all originally developed as SOD mimics. The same thermodynamic and electrostatic properties that make them potent SOD mimics may allow them to reduce other reactive species such as peroxynitrite, peroxynitrite-derived CO(3)(*-), peroxyl radical, and less efficiently H(2)O(2). By doing so SOD mimics can decrease both primary and secondary oxidative events, the latter arising from the inhibition of cellular transcriptional activity. To better judge the therapeutic potential and the advantage of one over the other type of compound, comparative studies of different classes of drugs in the same cellular and/or animal models are needed. We here provide a comprehensive overview of the chemical properties and some in vivo effects observed with various classes of compounds with a special emphasis on porphyrin-based compounds.