Characterization of extracellular trap production and release by equine neutrophils in response to different stimuli

This study explores Neutrophil Extracellular Trap (NET) formation in equine neutrophils, which is crucial for eliminating infections and is implicated in various equine inflammatory diseases. We investigated the molecular pathways involved in NET release by equine neutrophils in response to stimuli. We use PMA, A23187, LPS, PAF, OZ, and cytokines, observing NET release in response to PMA, PAF, and A23187. In contrast, LPS, OZ, and the cytokines tested did not induce DNA release or did not consistently induce citrullination of histone 4. Peptidyl-arginine deiminase inhibition completely halted NET release, while NADPH oxidase and mitochondrial reactive oxygen species only played a role in PMA-induced NETs. Neutrophil elastase inhibition modestly affected PAF-induced NET liberation but not in PMA or A23187-induced NET, while myeloperoxidase did not contribute to NET release. We expect to provide a foundation for future investigations into the role of NETs in equine health and disease and the search for potential therapeutic targets.

Effects of tamoxifen on the immune response phenotype in equine peripheral blood mononuclear cells

Tamoxifen (TAM) is widely utilized in the prevention and treatment of human breast cancer and has demonstrated the potential to modulate the immune response. It has been proposed as a therapeutic tool for immune-mediated diseases. TAM has been investigated as a possible treatment for asthma-like conditions in horses, revealing specific impacts on the innate immune system. While the effects of TAM on equine neutrophils are well-documented, its influence on lymphocytes and the modulation of the immune response polarization remains unclear. This in vitro study employed peripheral blood mononuclear cells (PBMC) from healthy horses, exposing them to varying concentrations of the TAM and assessing the expression of genes involved in the polarization of the immune response (TBX21, IFNG, GATA3, IL4, IL10, FOXP3, and CTLA4) in PBMC stimulated or not with PMA/ionomycin. Additionally, the effect of TAM over the proportion of regulatory T cells (Treg) was also assessed. TAM did not significantly affect the expression of these genes and Treg at low concentrations. However, at the highest concentration, there was an impact on the expression of GATA3, IL4, IL10, and CTLA4 genes. These alterations in genes associated with a Th2 and regulatory response coincided with a noteworthy increase in drug-associated cytotoxicity but only at concentrations far beyond those achieved in pharmacological therapy. These findings suggest that the effects of TAM, as described in preclinical studies on asthmatic horses, may not be attributed to the modification of the adaptive response.

d-lactate-induced ETosis in cattle polymorphonuclear leucocytes is dependent on the release of mitochondrial reactive oxygen species and the PI3K/Akt/HIF-1 and GSK-3β pathways

d-lactate is a metabolite originating from bacterial metabolism that accumulates as a result of dietary disturbances in cattle, leading to ruminal acidosis. d-lactate exerts functions as a metabolic signal inducing metabolic reprogramming and extracellular trap (ET) release in polymorphonuclear leucocytes (PMNs). We previously demonstrated that d-lactate induces metabolic reprogramming via hypoxia-induced factor 1 alpha (HIF-1α) stabilization in bovine fibroblast-like synoviocytes (FLSs). In the present study, the role of HIF-1 in ET formation induced by d-lactate was assessed. HIF-1α stabilization in PMNs was controlled by mitochondrial reactive oxygen species (_mtROS) release. Furthermore, inhibition of mitochondrial complex I and scavenging of _mtROS decreased d-lactate-triggered ETosis. d-lactate-enhanced HIF-1α accumulation was dependent on the PI3K/Akt pathway but independent of GSK-3β activity. Pharmacological blockade of the PI3K/Akt/HIF-1 and GSK-3β axes inhibited d-lactate-triggered ETosis and downregulated PDK1 and LDHA expression. However, only GSK-3β inhibition decreased the expression of glycogen metabolism enzymes and prevented the decline in glycogen stores induced by d-lactate exposure. The results of this study suggest that _mtROS, PI3K/Akt/HIF-1 and GSK-3β axes regulate carbohydrate metabolism adaptations that support d-lactate-induced ET formation in cattle.

Bovine tumor necrosis factor-alpha Increases IL-6, IL-8, and PGE2 in bovine fibroblast-like synoviocytes by metabolic reprogramming

Lameness is a common condition in dairy cattle caused by infectious or noninfectious agents. Joint lesions are the second most common cause of lameness and can be diagnosed in association with the presentation of digit injuries. Fibroblast-like synoviocyte (FLS) are predominant cells of synovia and play a key role in the pathophysiology of joint diseases, thus increasing the expression of proinflammatory mediators. Tumor necrosis factor-alpha (TNF-α) is a potent proinflammatory cytokine involved in cyclooxygenase 2 (COX-2) and proinflammatory cytokine expression in FLS. Previously, TNF-α was demonstrated to increase hypoxia-inducible Factor 1 (HIF-1), a transcription factor that rewires cellular metabolism and increases the expression of interleukin (IL)-6 in bovine FLS (bFLS). Despite this, the proinflammatory effects of TNF-α in bFLS on metabolic reprogramming have been poorly studied. We hypothesized that TNF-α increases glycolysis and in this way controls the expression of IL-6, IL-8, and COX-2 in bFLS. Results first, gas chromatography/mass spectrometry (GC/MS)-based untargeted metabolomics revealed that bTNF-α altered the metabolism of bFLS, increasing glucose, isoleucine, leucine, methionine, valine, tyrosine, and lysine and decreasing malate, fumarate, α-ketoglutarate, stearate, palmitate, laurate, aspartate, and alanine. In addition, metabolic flux analysis using D-glucose-¹³C₆ demonstrated an increase of pyruvate and a reduction in malate and citrate levels, suggesting a decreased flux toward the tricarboxylic acid cycle after bTNF-α stimulation. However, bTNF-α increased lactate dehydrogenase subunit A (LDHA), IL-6, IL-8, IL-1β and COX-2 expression, which was dependent on glycolysis and the PI3K/Akt pathway. The use of FX11 and dichloroacetate (DCA), an inhibitor of LDHA and pyruvate dehydrogenase kinase (PDK) respectively, partially reduced the expression of IL-6. Our results suggest that bTNF-α induces metabolic reprogramming that favors glycolysis in bFLS and increases IL-6, IL-8, IL-1β and COX-2/PGE2.

Hydroxycarboxylic acid receptor 2 (HCA2) agonists induce NET formation and MMP-9 release from bovine polymorphonuclear leukocytes

Periparturient cows are commonly fed diets supplemented with Niacin (nicotinic acid, NA) because of its anti-lipolytic properties. NA confers its anti-lipolytic effects by activating the hydroxycarboxylic acid 2 receptor (HCA2). HCA2 is also activated by the ketone body beta-hydroxybutyrate (BHB) and circulating BHB levels are elevated in postpartum dairy cows. The HCA2 receptor is highly expressed in bovine polymorphonuclear leukocytes (PMN) and could link metabolic and innate immune responses in cattle. We investigated how HCA2 agonists affected bovine PMN function in vitro. We studied different PMN responses, such as granule release, surface expression of CD11b and CD47, generation of neutrophil extracellular traps (NETs), and apoptosis. NA, BHB, and 4,4aR,5,5aR-tetrahydro-1H-cyclopropa [4,5] cyclopenta [1,2-c] pyrazole-3-carboxylic acid (MK-1903) treatment triggered the release of matrix metalloproteinase 9 (MMP-9), a component of the tertiary granule, from neutrophils. Additionally, all HCA2 agonists induced NETs formation but did not affect surface expression of CD11b and CD47. Finally, none of the HCA2 agonists triggered apoptosis in bovine PMN. This information will give new insights into the potential role of the HCA2 receptor in the bovine innate immune response.

Tamoxifen triggers the in vitro release of neutrophil extracellular traps in healthy horses

Neutrophils display an array of biological functions including the formation of neutrophil extracellular traps (NETs), web-like structures specialized in trapping, neutralizing, killing and preventing microbial dissemination within the host. However, NETs contribute to a number of inflammatory pathologies, including severe equine asthma. Tamoxifen (TX) is a selective estrogen receptor modulator which belongs to the triphenylethyllenes group of molecules, and which is used as a treatment in all stages of estrogen-positive human breast cancer. Our previous results suggest that tamoxifen can modulate neutrophil functionality and promote resolution of inflammation; this would partly explain the clinical beneficial effect of this drug in horses with airway inflammation. Enhanced NETs production has been reported with tamoxifen use in humans, but minimal data exists regarding the drug's effect on NETs in horses. The aim of this study is to assess the in vitro effect of TX on NETs formation from peripheral blood of healthy horses. Five clinically healthy mixed-breed adult horses were enrolled in the study. For this, cellular free DNA quantification, immunofluorescence for the visualization of NETs, assessment of different types of NETs, and detection of mitochondrial superoxide. TX induced NETs formation at a concentration of 10 uM. Our results show that only two types of NETs were induced by TX: 95% spread NETs (sprNETs) and 5% aggregated NETs (aggNETs). Furthermore, induction of these NETs could be influenced by mitochondrial ROS. Future research should involve an In vivo study of horses with severe asthma and TX treatment, to evaluate BALF neutrophil NET formation. In conclusion, this in vitro study suggests that the resolution of inflammation by TX in horses with airway inflammation is due to inhibition of other neutrophilic functions but not to NET formation.

d-lactate-triggered extracellular trap formation in cattle polymorphonuclear leucocytes is glucose metabolism dependent

D-lactic acidosis is a metabolic disease of cattle caused by the digestive overgrowth of bacteria that are highly producers of d-lactate, a metabolite that then reaches and accumulates in the bloodstream. d-lactate is a proinflammatory agent in cattle that induces the formation of extracellular traps (ETs) in polymorphonuclear leucocytes (PMN), although information on PMN metabolic requirements for this response mechanism is insufficient. In the present study, metabolic pathways involved in ET formation induced by d-lactate were studied. We show that d-lactate but not l-lactate induced ET formation in cattle PMN. We analyzed the metabolomic changes induced by d-lactate in bovine PMN using gas chromatography-mass spectrometry (GC-MS). Several metabolic pathways were altered, including glycolysis/gluconeogenesis, amino sugar and nucleotide sugar metabolism, galactose metabolism, starch and sucrose metabolism, fructose and mannose metabolism, and pentose phosphate pathway. d-lactate increased intracellular levels of glucose and glucose-6-phosphate, and increased uptake of the fluorescent glucose analog 2-NBDG, suggesting improved glycolytic activity. In addition, using an enzymatic assay and transmission electron microscopy (TEM), we observed that d-lactate was able to decrease intracellular glycogen levels and the presence of glycogen granules. Relatedly, d-lactate increased the expression of enzymes of glycolysis, gluconeogenesis and glycogen metabolism. In addition, 2DG (a hexokinase inhibitor), 3PO (a 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 inhibitor), MB05032 (inhibitor of fructose-1,6-bisphosphatase) and CP-91149 (inhibitor of glycogen phosphorylase) reduced d-lactate-triggered ETosis. Taken together, these results suggest that d-lactate induces a metabolic rewiring that increases glycolysis, gluconeogenesis and glycogenolysis, all of which are required for d-lactate-induced ET release in cattle PMN.

Novel Proteoliposome-Based Vaccine against E. coli: A Potential New Tool for the Control of Bovine Mastitis

Simple Summary

Mastitis is a highly prevalent disease in dairy cattle, affecting animal welfare and generating economic losses for the dairy industry. Control measures for coliform mastitis are limited, due to the constant exposure of the teat to bacteria and the emergence of antimicrobial-resistant bacteria, making vaccination an important strategy for control of mastitis. However, currently available vaccines show limited efficacy, which could be attributed to inactivation processes that alter the antigenic preservation of the vaccines. The aim of this study was to assess the efficacy of a novel vaccine against mastitis using proteoliposomes obtained from E. coli in a murine model of coliform mastitis. We demonstrated that the proteoliposome vaccine was safe, immunogenic and effective against an experimental model of E. coli mastitis, decreasing bacterial count and tissue damage. This proteoliposome vaccine is a potential new tool for prevention of mastitis.

Abstract

Escherichia coli is an important causative agent of clinical mastitis in cattle. Current available vaccines have shown limited protection. We evaluated the efficacy of a novel vaccine based on bacterial proteoliposomes derived from an E. coli field strain. Female BALB/c mice were immunized subcutaneously with two doses of the vaccine, 3 weeks apart. Between days 5 and 8 after the first inoculation, the females were mated. At 5–8 days postpartum, the mice were intramammary challenged with the same E. coli strain. Two days after bacterial infection, mice were euthanized, and the mammary glands were examined and removed to evaluate the efficacy and safety of the vaccine as well as the immune response generated by the new formulation. The vaccinated mice showed mild clinical symptoms and a lower mammary bacterial load as compared to non-vaccinated animals. The vaccination induced an increase in levels of IgG, IgG1 and IgG2a against E. coli in blood and mammary glands that showed less inflammatory infiltration and tissue damage, as compared to the control group. In summary, the vaccine based on bacterial proteoliposomes is safe, immunogenic, and effective against E. coli, constituting a new potential tool for mastitis control.

Role of Cellular Metabolism in the Formation of Neutrophil Extracellular Traps in Airway Diseases

Neutrophil extracellular traps (NETs) are a recently described mechanism of neutrophils that play an important role in health and disease. NETs are an innate defense mechanism that participate in clearance of pathogens, but they may also cause collateral damage in unrelated host tissues. Neutrophil dysregulation and NETosis occur in multiple lung diseases, such as pathogen-induced acute lung injury, pneumonia, chronic obstructive pulmonary disease (COPD), severe asthma, cystic fibrosis, and recently, the novel coronavirus SARS-CoV-2. More recently, research into immunometabolism has surged due to the possibility of reprogramming metabolism in order to modulate immune functions. The present review analyzes the different metabolic pathways associated with NETs formation, and how these impact on pathologies of the airways.

Role of Lactate in Inflammatory Processes: Friend or Foe

During an inflammatory process, shift in the cellular metabolism associated with an increase in extracellular acidification are well-known features. This pH drop in the inflamed tissue is largely attributed to the presence of lactate by an increase in glycolysis. In recent years, evidence has accumulated describing the role of lactate in inflammatory processes; however, there are differences as to whether lactate can currently be considered a pro- or anti-inflammatory mediator. Herein, we review these recent advances on the pleiotropic effects of lactate on the inflammatory process. Taken together, the evidence suggests that lactate could exert differential effects depending on the metabolic status, cell type in which the effects of lactate are studied, and the pathological process analyzed. Additionally, various targets, including post-translational modifications, G-protein coupled receptor and transcription factor activation such as NF-κB and HIF-1, allow lactate to modulate signaling pathways that control the expression of cytokines, chemokines, adhesion molecules, and several enzymes associated with immune response and metabolism. Altogether, this would explain its varied effects on inflammatory processes beyond its well-known role as a waste product of metabolism.

Participation of Short-Chain Fatty Acids and Their Receptors in Gut Inflammation and Colon Cancer

Short-chain fatty acids (SCFAs) are the main metabolites produced by the bacterial fermentation of dietary fiber, and they play a critical role in the maintenance of intestinal health. SCFAs are also essential for modulating different processes, and they have anti-inflammatory properties and immunomodulatory effects. As the inflammatory process predisposes the development of cancer and promotes all stages of tumorigenesis, an antitumor effect has also been associated with SCFAs. This is strongly supported by epidemiological studies showing that a diet rich in fiber is linked to a reduced risk of colon cancer and has significant clinical benefits in patients with inflammatory bowel disease (IBD). SCFAs may signal through the metabolite-sensing G protein-coupled receptors free fatty acid receptor 3 [FFAR3 or G protein-coupled receptor 41 (GPR41)], FFAR2 (GPR43), and GPR109A (also known as hydroxycarboxylic acid receptor 2 or HCAR2) expressed in the gut epithelium and immune cells. This review summarizes the existing knowledge regarding the SCFA-mediated suppression of inflammation and carcinogenesis in IBD and colon cancer.

Metabolic Reprogramming and Inflammatory Response Induced by D-Lactate in Bovine Fibroblast-Like Synoviocytes Depends on HIF-1 Activity

Acute ruminal acidosis (ARA) occurs after an excessive intake of rapidly fermentable carbohydrates and is characterized by the overproduction of D-lactate in the rumen that reaches the bloodstream. Lameness presentation, one of the primary consequences of ARA in cattle, is associated with the occurrence of laminitis and aseptic polysynovitis. Fibroblast-like synoviocytes (FLS) are predominant cells of synovia and play a key role in the pathophysiology of joint diseases, thus increasing the chances of the release of pro-inflammatory cytokines. Increased D-lactate levels and disturbances in the metabolism of carbohydrates, pyruvates, and amino acids are observed in the synovial fluid of heifers with ARA-related polysynovitis prior to neutrophil infiltration, suggesting an early involvement of metabolic disturbances in joint inflammation. We hypothesized that D-lactate induces metabolic reprogramming, along with an inflammatory response, in bovine exposed FLS. Gas chromatography-mass spectrometry (GC-MS)-based metabolomics revealed that D-lactate disrupts the metabolism of bovine FLS, mainly enhancing glycolysis and gluconeogenesis, pyruvate metabolism, and galactose metabolism. The reverse-transcription quantitative PCR (RT-qPCR) analysis revealed an increased expression of metabolic-related genes, including hypoxia-inducible factor 1 (HIF-1)α, glucose transporter 1 (Glut-1), L-lactate dehydrogenase subunit A (L-LDHA), and pyruvate dehydrogenase kinase 1 (PDK-1). Along with metabolic disturbances, D-lactate also induced an overexpression and the secretion of IL-6. Furthermore, the inhibition of HIF-1, PI3K/Akt, and NF-κB reduced the expression of IL-6 and metabolic-related genes. The results of this study reveal a potential role for D-lactate in bFLS metabolic reprogramming and support a close relationship between inflammation and metabolism in cattle.

COVID-19 retinal microangiopathy as an in vivo biomarker of systemic vascular disease?

IMPORTANCE

COVID-19 is caused by SARS-CoV-2, a betacoronavirus that uses the angiotensin-converting enzyme-related carboxypeptidase (ACE2) receptor to gain entry into cells. ACE2 receptor is widely expressed in multiple organs, including the retina, an extension of the central nervous system. The ACE2 receptor is involved in the diabetic and hypertensive retinopathy. Additionally, coronaviruses cause ocular infections in animals, including retinitis, and optic neuritis.

OBJECTIVE

To assess whether there is any retinal disease associated with COVID-19.

DESIGN

We have evaluated 27 asymptomatic subjects, with retinal fundoscopic, optical coherence tomography (OCT) and OCT angiography fourteen days after hospital discharge due to COVID-19 bilateral pneumonia.

RESULTS

Cotton wool exudates were evident in six out of 27 patients evaluated, a 22%. Cotton wool exudates are a marker vascular disease severity in other medical context, that is diabetes and hypertension, and are associated with increased risk for acute vascular events. Whether antiaggregation therapy may play a role on fundoscopic-selected patients with COVID-19 requires prospective trials.

Andrographolide, an Anti-Inflammatory Multitarget Drug: All Roads Lead to Cellular Metabolism

Andrographolide is a labdane diterpene and the main active ingredient isolated from the herb Andrographis paniculata. Andrographolide possesses diverse biological effects including anti-inflammatory, antioxidant, and antineoplastic properties. Clinical studies have demonstrated that andrographolide could be useful in therapy for a wide range of diseases such as osteoarthritis, upper respiratory diseases, and multiple sclerosis. Several targets are described for andrographolide, including the interference of transcription factors NF-κB, AP-1, and HIF-1 and signaling pathways such as PI3K/Akt, MAPK, and JAK/STAT. In addition, an increase in the Nrf2 (nuclear factor erythroid 2–related factor 2) signaling pathway also supports its antioxidant and anti-inflammatory properties. However, this scenario could be more complex since recent evidence suggests that andrographolide targets can modulate glucose metabolism. The metabolic effect of andrographolide might be the key to explaining the diverse therapeutic effects described in preclinical and clinical studies. This review discusses some of the most recent evidence about the anti-inflammatory and metabolic effects of andrographolide.

Mitochondria-derived ATP participates in the formation of neutrophil extracellular traps induced by platelet-activating factor through purinergic signaling in cows

Neutrophil extracellular trap (NET) formation eliminates/prevents the spread of infectious agents. Platelet activating factor (PAF) is involved in infectious diseases of cattle because it recruits and activates neutrophils. However, its ability to induce NET release and the role of metabolism in this process is not known. We investigated if inhibition of glycolysis, mitochondrial-derived adenosine triphosphate (ATP) synthesis and purinergic signaling though P2X₁ purinoceptors interfered with NET formation induced by PAF. We inhibited bovine neutrophils with 2-deoxy-d-glucose, rotenone, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and NF449 to evaluate PAF-mediated NET extrusion. PAF induced mitochondrial hyperpolarization and triggered extracellular ATP release via pannexin-1. Inhibition of mitochondrial metabolism prevented extracellular ATP release. Inhibition of glycolysis, complex-I activity and oxidative phosphorylation prevented NET formation induced by PAF. Inhibition of P2X₁ purinergic receptors inhibited mitochondrial hyperpolarization and NET formation. We concluded that PAF-induced NET release is dependent upon glycolysis, mitochondrial ATP synthesis and purinergic signaling.

Oleic and Linoleic Acids Induce the Release of Neutrophil Extracellular Traps via Pannexin 1-Dependent ATP Release and P2X1 Receptor Activation

Non-esterified fatty acids (NEFAs) such as oleic acid (OA) and linoleic acid (LA) are associated with a higher incidence of infectious diseases such as metritis and mastitis during the bovine peripartum. Fatty acids can induce an increase in the release of ATP, and changes in the expression levels of purinergic receptors in bovine polymorphonuclears (PMN) during peripartum have also been reported. PMN respond to inflammatory processes with production of ROS, release of proteolytic and bactericidal proteins, and formation of neutrophil extracellular traps (NETs). NETs formation is known to require ATP production through glycolysis. Studies have shown that the above-mentioned metabolic changes alter innate immune responses, particularly in PMN. We hypothesized that NEFAs induce the formation of NETs through ATP release by Pannexin 1 and activation of purinergic receptors. In this study, we found that OA and LA induce NET formation and extracellular ATP release. Carbenoxolone, a pannexin-1 (PANX1) inhibitor, reduced OA- and LA-induced ATP release. We also found that P2X1, P2X4, P2X5, P2X7, and PANX1 were expressed at the mRNA level in bovine PMN. Additionally, NEFA-induced NET formation was completely abolished with exposure to NF449, a P2X1 antagonist, and partially inhibited by treatment with etomoxir, an inhibitor of fatty acid oxidation (FAO). Our results suggest that OA and LA induce NET formation and ATP release via PANX1 and activation of P2X1. These new data contribute to explaining the effects of NEFA high concentrations during the transition period of dairy cattle and further understanding of pro-inflammatory effects and outcome of postpartum diseases.

Glycolysis and mitochondrial function regulate the radical oxygen species production induced by platelet-activating factor in bovine polymorphonuclear leukocytes

Dairy cows undergo metabolic disturbances in the peripartum period, during which infectious inflammatory diseases and detrimental polymorphonuclear leukocytes (PMN) functions, such as radical oxygen species (ROS) production, are observed. Platelet-activating factor (PAF) is a key pro-inflammatory mediator that increases PMN ROS production. To date, the role of glycolysis and mitochondria in PAF-induced ROS production in bovine PMN has not been known. The aim of this study was to assess whether inhibition of glycolysis and disruption of mitochondrial function alter the oxidative response induced by PAF. We isolated PMN from non-pregnant Holstein Friesian heifers and pre-incubated them with 2-deoxy-d-glucose (2-DG; 2 mM, 30 min), carbonyl cyanide 3-chlorophenylhydrazone (CCCP; 5 μM, 5 min), oligomycin (10 μM, 30 min) or rotenone (10 μM, 30 min). Respiratory burst was measured by luminol-chemiluminescence assay, while mitochondrial ROS (_mtROS) were evaluated by MitoSOX probe and flow cytometry. Also, we detected the presence of mitochondria by MitoTracker Deep Red FM probe and changes in mitochondrial membrane potential (Δψ_m) were assessed by JC-1 probe and flow cytometry. We observed that all inhibitors separately were able to reduce PAF-induced ROS production. Presence of mitochondria was detected and PAF increased the Δψ_m, while CCCP reduced it. 2-DG and rotenone reduced the _mtROS production induced by PAF. CCCP did not alter the _mtROS and oligomycin administered independently increased _mtROS production. We concluded that PAF-induced ROS production is glycolysis- and mitochondria-dependent. Bovine PMN have a functional mitochondrion and PAF induced _mtROS via glycolysis and mitochondrial complex-I activity. Our results highlight an important modulation of cellular metabolism in the oxidative response induced by proinflammatory agents, which could contribute to PMN disfunction during peripartum in cattle.

[Factors modulating food intake and energy expenditure prior to liver transplantation]

BACKGROUND

There is a high prevalence of nutritional disorders in patients with liver cirrhosis (LC). This study was designed to assess the relationships between liver function, IFG-I/IGFBP-3, nutritional status, leptin, ghrelin and glucagon in 21 patients waiting for liver transplantation (LT).

METHODS

We studied 21 men aged 56±2.1 years who were on the LT list. They were classified according to Child-Pugh(CP) score from low to high liver dysfunction in CPA (n=4),CPB (n=11) and CPC (n=6). Body mass index (BMI) was calculated and body fat (%) was measured by air-displacement plethysmography. Resting energy expenditure (REE) and its variation over Harris-Benedict values (GER%) were assessed by indirect calorimetry. Fasting serum samples were taken to measure albumin, glucose, insulin, HbA1c, leptin, total ghrelin,glucagon, IGF-I and IGFBP3.

RESULTS

There were no differences in fat % and leptin values in the three groups according to CP classification. The CPC group showed higher ghrelin values than CPA and CPB(p<0.05). All groups displayed high glucagon levels and GER%values superior to 100%. Positive correlations were found between glucagon and GER% (r=0.56; p<0.01) and between glucagon and ghrelin values (r=0.66; p<0.01). IGF-I and IGFBP3 were low in all groups and showed a positive correlation with plasma albumin (r=0.52; p<0.05 and r=0.45; p<0.05 respectively).

CONCLUSIONS

These results show an increase in ghrelin plasma values in patients with severe liver dysfunction. Hyperglucagonemia was correlated with GER%, supporting a role of glucagon in the hypermetabolic state associated to LC,raising the possibility of becoming a therapeutic target. The measurement of IGF-I/IGFBP3 represents a good marker of liver function in patients with LC.

Efficacy of transjugular intrahepatic portosystemic shunt to prevent total portal vein thrombosis in cirrhotic patients awaiting for liver transplantation

INTRODUCTION

Complete portal vein thrombosis (PVT) may complicate orthotopic liver transplantation (OLT), increasing its technical difficulty and the transfusion requirements and as well as affecting survival in some cases. Transjugular intrahepatic portosystemic shunt (TIPS) prevents total portal vein occlusion in patients with partial PVT.

OBJECTIVE

We aimed to assess the efficacy and safety of TIPS to prevent total portal vein occlusion among patients listed for OLT.

PATIENTS AND METHODS

We analyzed the clinical records of 15 consecutive patients with partial PVT who underwent TIPS before OLT. The control group consisted of 8 transplanted patients without TIPS but partial PVT diagnosed before OLT. Portal vein patency at surgery, ischemia time, and transfusion requirements during OLT, and survival thereafter were compared between both groups. The main complications were also compared: mortality after TIPS (from TIPS placement to OLT), intraoperative technical complications, and technical complications during the 6 months after OLT.

RESULTS

Clinical characteristics at the time of OLT were similar between the groups. No relevant complications were observed after TIPS; all patients underwent transplantation. One- and 5-year actuarial survival rates were similar in both groups (92% and 85% in TIPS-group versus 100 and 75% in the control group, respectively). No differences in transfusion requirement, duration of ischemia, and frequency of technical complications during and after OLT were observed between the groups. The portal vein was patent at surgery in all TIPS patients and 4 of 8 (50%) in the control group (P = .008).

CONCLUSION

TIPS may prevent PVT in liver transplantation candidates with partial PVT.

Increased liver stiffness values in patients with heart failure

BACKGROUND

Liver stiffness has been claimed to be increased in patients with heart failure.

AIMS

To determine the magnitude of this increase in liver stiffness, and to clarify whether it is related to the degree of heart failure or not.

METHODS

Twenty-six patients were prospectively collected, and divided in groups CHF (those with compensated chronic heart failure) and AHF (those with acute decompensated heart failure). Patients underwent routine blood chemistries, pro-BNP determination, echocardiography and transient elastography during outpatient care (group CHF) or at hospital admission (group AHF). Blood chemistries, pro-BNP and transient elastography were repeated in patients in group AHF before being discharged.

RESULTS

Correlation between liver stiffness and pro-BNP levels was statistically significant (Rho = 0.747, p = 0.001). Patients in group CHF had lower values of liver stiffness and pro-BNP when compared with patients in group AHF at admission. Median liver stiffness and pro-BNP values were 6.5 vs 14.4 kPa (p = 0.009) and 1511 vs 3535 pg/ml (p = 0.025) respectively. After clinical compensation, liver stiffness decreased in all patients in group AHF. Liver stiffness was 14.4 kPa at admission and 8.2 kPa at discharge (p = 0.008). Pro-BNP values also decreased from a median of 3535 pg/ml to a median of 1098 pg/ml (p = 0.025).

CONCLUSIONS

Patients with heart failure have increased liver stiffness, that appears to be related with the severity of heart failure.

Subsequent nonmelanoma skin cancer after liver transplantation

BACKGROUND

Liver transplant recipients have a high risk of developing nonmelanoma skin cancer (NMSC). Some develop multiple NMSC.

METHODS

Patients with a follow-up of >1 year have been prospectively followed to detect NMSC. We studied the risk of developing >1 NMSC.

RESULTS

After a follow-up of 2658 patient-years (mean, 8.5 years per patient), 59/312 (19%) patients were diagnosed with NMSC. Twenty-five had >1 NMSC. The 5-year risk of developing 1 NMSC, >1 NMSC, and a subsequent NMSC (a new NMSC after a first one) were 15%, 5.5%, and 46.5%, respectively. Age >60 years and transplantation for hepatocellular carcinoma were independently associated with a higher risk of developing >1 NMSC.

CONCLUSION

NMSC are frequent complications after liver transplantation and they may show a high rate of recurrence. Older age and hepatocellular carcinoma were related to the development of multiple NMSC.

Applicability of living donor liver transplantation in a program of adult liver transplantation

INTRODUCTION

The aim of this study was to investigate the applicability of living donor liver transplantation in a program of adult liver transplantation.

PATIENTS AND METHODS

We studied the outcomes of the evaluation of 71 potential donor candidates for 53 adult candidates to liver transplantation.

RESULTS

Ten of the potential donor candidates did not complete their evaluation. Among the remaining 61 potential donors, 29 (47.5%) were considered to be suitable donors. Only 17 (24% of the 71 initial candidates) underwent donation. The main causes for unsuitability for liver donation were a small remnant liver and vascular anatomic variants.

CONCLUSION

Fewer than 25% of potential liver donors became effective donors leading us to conclude that adult living donor liver transplantation has a low applicability.

[Insulin-like growth factor I (IGF-I) and liver cirrhosis]

Insulin-like growth factor I (IGF-I) is a polypeptide hormone secreted by multiple tissues in response to growth hormone (GH). It is partly responsible for GH activity, and also has glucose-lowering and anabolizing effects. Ninety percent of circulating IGF-I originates in the liver and has autocrine, paracrine, and endocrine effects, the latter on multiple tissues. Liver cirrhosis results in a progressive decline of hepatic IGF-I output, and this factor may become undetectable in advanced disease. Some cirrhosis complications, mainly those nutritional and metabolic in nature (insuline resistance, malnutrition, osteopenia, hypogonadism, intestinal disorders), may be at least partly related to this IGF-I deficiency, since some IGF-I effects represent a reverse image of cirrhosis complications. Despite this, IGF-I replacement therapy has been never suggested for cirrhosis. A number of experimental studies in cirrhotic rats showed that therapy using low-dose recombinant IGF-I exerts two types of effect on experimental cirrhosis: a) liver improvement driven by improved hepatocellular function, portal hypertension, and liver fibrosis; and b) cirrhosis-related extrahepatic disorder improvement driven by improved food efficiency, muscle mass, bone mass, gonadal function and structure, and intestinal function and structure, with a normalization of sugar and amino acid malabsorption, and improved intstinal barrier function, manifested by reduced endotoxemia and bacterial translocation. Subsequently, the first randomized, double-blind, placebo-controlled, pilot clinical trial in a small number of cirrhotic patients showed increased serum albumin and improved energy metabolism as a result of IGF-I use. Further clinical trials are needed to identify adequate IGF-I doses, administration duration and frequency, and the subgroup of cirrhotic patients who will benefit most from this replacement therapy.

Insulin-like growth factor I improves intestinal barrier function in cirrhotic rats

BACKGROUND AND AIMS

In liver cirrhosis, disruption of the intestinal barrier facilitates bacterial translocation and spontaneous bacterial peritonitis. Insulin-like growth factor I (IGF-I) is an anabolic hormone synthesised by hepatocytes that displays hepatoprotective activities and trophic effects on the intestine. The aim of this study was to investigate the effect of IGF-I on intestinal barrier function in cirrhotic rats.

METHODS

In rats with carbon tetrachloride induced cirrhosis, we investigated the effect of IGF-I therapy on: (a) portal pressure; (b) intestinal histology and permeability to endotoxin and bacteria; (c) intestinal expression of cyclooxygenase 2 (COX-2) and tumour necrosis factor alpha (TNF-alpha), two factors that influence in a positive and negative manner, respectively, the integrity of the intestinal barrier; (d) intestinal permeability to 3H-mannitol in rats with bile duct ligation (BDL); and (e) transepithelial electrical resistance (TER) of polarised monolayers of rat small intestine epithelial cells.

RESULTS

IGF-I therapy reduced liver collagen expression and portal pressure in cirrhotic rats, induced improvement in intestinal histology, and caused a reduction in bacterial translocation and endotoxaemia. These changes were associated with diminished TNF-alpha expression and elevated COX-2 levels in the intestine. IGF-I reduced intestinal permeability in BDL rats and enhanced barrier function of the monolayers of epithelial intestinal cells where lipopolysaccharide (LPS) caused a decrease in TER that was reversed by IGF-I. This effect of IGF-I was associated with upregulation of COX-2 in LPS treated enterocytes.

CONCLUSIONS

IGF-I enhances intestinal barrier function and reduces endotoxaemia and bacterial translocation in cirrhotic rats. IGF-I therapy might be useful in the prevention of spontaneous bacterial peritonitis in liver cirrhosis.

[Liver transplantation]

Liver transplantation is an efficient therapeutic option for terminal hepatic diseases. The principal indications of liver transplantation are hepatic cirrhosis, hepatic tumours (mainly, hepatocellular carcinoma) and acute liver failure. Over the years, the absolute contraindications for a transplant have lessened. Surgical techniques have also undergone changes. The results of liver transplant have improved so that survival one year after the transplant is close to 90% and after five years some 80% of transplanted patients continue to live.

[Acute infection by hepatitis B virus]

The clinical spectrum of acute hepatitis B virus infection is very broad, with clinical manifestations that range from anicteric and sub-clinical hepatitis to severe acute icteric hepatitis and even, in some cases, to fulminant hepatitis. Diagnosis depends to a large extent on the degree of clinical suspicion of hepatitis, establishing the aetiological origin of the B virus through the study of serological markers and/or DNA in the blood. Although in the majority of cases there is a favourable evolution of acute hepatitis B virus infection, with spontaneous resolution of the clinical manifestations in 4-8 weeks, progression to chronic hepatitis is not unusual in certain cases, above all in infancy. No specific treatment exists for acute hepatitis B virus infection that would reduce its severity or prevent its evolution into chronic hepatitis. However, relative rest and the administration of an hypercaloric diet are recommended. In cases of severe acute hepatitis hospital admission should be recommended; in cases of fulminant hepatitis, admission to the intensive care unit for intensive monitoring and evaluation of a liver transplantation is recommended if spontaneous improvement does not occur. This paper reviews briefly the clinical manifestations, diagnosis, prognosis and treatment of acute hepatitis B virus infection.

Conversion from calcineurin inhibitors to mycophenolate mofetil in liver transplant recipients with diabetes mellitus

Diabetes mellitus, a frequent metabolic complication in liver transplant recipients, may be produced by the diabetogenic effect of calcineurin inhibitors cyclosporine and tacrolimus. The aim of this study was to investigate the safety and metabolic effects of a gradual switch from cyclosporine or tacrolimus to mycophenolate mofetil among 12 diabetic liver transplant recipients. One patient was withdrawn from the study due to gastrointestinal side effects. Of the 11 remaining patients, cyclosporine or tacrolimus was completely withdrawn in five patients. Two patients developed suspected acute rejection episodes that were controlled by increasing the tacrolimus dosage. Glycosylated hemoglobin A1C and C-peptide levels were significantly lower at 3 and 6 months after the initiation of mycophenolate mofetil (P<.03 in all cases). Furthermore, urea and uric acid levels were significantly reduced after the change of treatment. In conclusion, a switch from cyclosporine/tacrolimus to mycophenolate mofetil may produce beneficial metabolic effects in diabetic liver transplant recipients, but poses a risk of graft rejection.

Integration of telemedicine into emergency medical services

We developed an integrated model of telemedicine services in emergency medical care. The architecture was designed to support pre-hospital management. The experimental work was carried out with the collaboration of the emergency medical services (EMS) in Madrid. Two different study populations were defined: a control population using conventional EMS protocols and a population using the telemedicine system. The telemedicine system was based on a telepresence service; electrocardiograms and images were transmitted from the ambulance to the health emergency coordination centre. The cost of dealing with 100 patients using telemedicine was C6030 less than the cost of conventional care. The response times using telemedicine were significantly lower.

IGF1 gene transfer into skeletal muscle using recombinant adeno-associated virus in a rat model of liver cirrhosis

Systemic administration of recombinant IGF1 at low levels has been shown to improve hepatic function, nutritional status and testicular atrophy in rats with CCl4-induced cirrhosis. We have developed a recombinant adeno-associated (rAAV) viral vector containing the cDNA for rat IGF1 and confirmed the expression of IGF1 after intramuscular injection of this vector in a rat model of liver cirrhosis. Although weight of injected muscles was significantly increased in rats with mild cirrhosis, this was not the case in rats with advanced, de-compensated cirrhosis. Furthermore, we found no significant amelioration of liver damage in treated rats at any stage of liver cirrhosis. Our results suggest that IGF1 gene transfer into muscle results in a local effect, at least at the vector dose employed here.

Effect of ursodeoxycholic acid on methionine adenosyltransferase activity and hepatic glutathione metabolism in rats

BACKGROUND AND AIMS

Both bile salts and glutathione participate in the generation of canalicular bile flow. In this work, we have investigated the effect of different bile salts on hepatic glutathione metabolism.

METHODS

Using the isolated and perfused rat liver, we studied hepatic glutathione content, and metabolism and catabolism of this compound in livers perfused with taurocholate, ursodeoxycholate, or deoxycholate.

RESULTS

We found that in livers perfused with ursodeoxycholate, levels of glutathione and the activity of methionine adenosyltransferase (an enzyme involved in glutathione biosynthesis) were significantly higher than in livers perfused with other bile salts. In ursodeoxycholate perfused livers, methionine adenosyltransferase showed a predominant tetrameric conformation which is the isoform with highest activity at physiological concentrations of substrate. In contrast, the dimeric form prevailed in livers perfused with taurocholate or deoxycholate. The hepatic activities of gamma-glutamylcysteine synthetase and gamma-glutamyltranspeptidase, enzymes involved, respectively, in biosynthetic and catabolic pathways of glutathione, were not modified by bile salts.

CONCLUSIONS

Ursodeoxycholate specifically enhanced methionine adenosyltransferase activity and hepatic glutathione levels. As glutathione is a defensive substance against oxidative cell damage, our observations provide an additional explanation for the known hepatoprotective effects of ursodeoxycholate.

An epidemiological study of Taenia solium cysticercosis in a rural population in the Bolivian Chaco

A survey of 100 rural households in a village in the Chaco region of Bolivia revealed a serious problem of Taenia solium cysticercosis, with a seroprevalence of 99/447 (22%) in humans and 102/273 (37%) in pigs. Risk factors for humans were being in older age groups, absence of sanitary facilities, poor formal education and inability to recognise infected pork. Significant risk indicators were a history of seizures and the reported elimination of worms in the faeces. Risk factors for pigs were being in older age groups and absence of sanitary facilities in the owner's house. The proportion of households with evidence of human cysticercosis was similar for those who owned pigs (48%) and those that did not (55%). This unexpected finding was attributed to the high overall prevalence of cysticercosis in pigs and the probability that everyone, regardless of pig-ownership, had ample opportunity to become infected in such communities. The main recommendation for reducing the prevalence of human cysticercosis was to provide more effective education campaigns, aimed at preventing both T. solium infection and cysticercosis.

Insulin-like growth factor-I restores the reduced somatostatinergic tone controlling growth hormone secretion in cirrhotic rats

BACKGROUND/AIMS

An altered growth hormone/insulin-like growth factor-I (GH/IGF-I) axis occurs in advanced liver cirrhosis, characterised by diminished serum levels of IGF-I and increased concentrations of GH. Under normal conditions, GH release is mediated by somatostatin (SS) inhibition. However, the influence of SS on GH release in cirrhosis is not well known. IGF-I supplementation has beneficial effects in experimental cirrhosis, and - under physiological conditions - IGF-I increases SS, inhibiting GH. The aims of this work were to study SS tone in cirrhotic animals and to evaluate whether IGF-I treatment influences SS tone, controlling GH secretion in cirrhosis.

METHODS

We studied the influence of SS on GH secretion by assessing GH response to pyridostigmine (PD) in cirrhotic rats treated and untreated with IGF-I. Liver cirrhosis was induced with CCl4-inhalation for 11 weeks in male Wistar rats. The animals were randomly divided into two groups: CI+IGF (n=12), which received IGF-I treatment for 12 days (2 microg/100 g body wt-1 x d-1) and CI (n=12), which received saline. Healthy controls (CO, n=12) were studied at the same time. On day 13, animals from each group were subdivided into two groups (n=6) in order to explore the effect of a PD intrajugular bolus (10 microg x 100 gbw-1) on serum GH levels (at 0,10,20,30 and 60 min), which were assessed by RIA.

RESULTS

PD bolus did not exert any effect on GH serum levels in the CI group, suggesting a low SS tone in cirrhotic rats. However, PD induced an increase in GH levels into CO and CI+IGF groups. In conclusion, as occurs under normal conditions, the cholinergic system is a significant modulator of GH secretion in experimental liver cirrhosis.

CONCLUSION

Cirrhotic rats have a reduced somatostatinergic tone which can be restored by IGF-I supplementation, suggesting that somatostatin is the main factor involved in the feed-back regulation between GH and IGF-I in cirrhosis.

4-(4-Chlorophenyl)-3,7,7-trimethyl-1-[2-(4-nitrobenzoyl)ethyl]-4,7,8,9-tetrahydro-1H-pyrazolo[3,4-b]quinolin-5(6H)-one-ethanol (1/1)

Molecules of the title compound, C(28)H(27)ClN(4)O(4).C(2)H(6)O, form a C(6) chain via an N--H...O hydrogen bond along the c axis by the operation of a c-glide plane, with N...O = 2.761 (3) A and N--H...O = 165 degrees. The molecules are further linked by a weak C--H...O interaction, with C.O = 3.344 (4) A and C--H...O = 150 degrees. Pendant hydrogen-bonded ethanol solvent molecules are attached to the chains by O--H...N hydrogen bonds, with O...N = 2.904 (3) A and O--H...N = 175 degrees.

Feature subset selection by genetic algorithms and estimation of distribution algorithms. A case study in the survival of cirrhotic patients treated with TIPS

The transjugular intrahepatic portosystemic shunt (TIPS) is an interventional treatment for cirrhotic patients with portal hypertension. In the light of our medical staff's experience, the consequences of TIPS are not homogeneous for all the patients and a subgroup dies in the first 6 months after TIPS placement. Actually, there is no risk indicator to identify this subgroup of patients before treatment. An investigation for predicting the survival of cirrhotic patients treated with TIPS is carried out using a clinical database with 107 cases and 77 attributes. Four supervised machine learning classifiers are applied to discriminate between both subgroups of patients. The application of several feature subset selection (FSS) techniques has significantly improved the predictive accuracy of these classifiers and considerably reduced the amount of attributes in the classification models. Among FSS techniques, FSS-TREE, a new randomized algorithm inspired on the new EDA (estimation of distribution algorithm) paradigm has obtained the best average accuracy results for each classifier.