Endotoxin alters serum-free choline and phospholipid-bound choline concentrations, and choline administration attenuates endotoxin-induced organ injury in dogs

Thromboelastographic evaluation of the effectiveness of choline or CDP-choline treatment on endotoxin-induced hemostatic alterations in dogs

Sepsis/endotoxemia associates with coagulation abnormalities. We showed previously that exogenous choline treatment reversed the changes in platelet count and function as well as prevented disseminated intravascular coagulation (DIC) in endotoxemic dogs. The aim of this follow-up study was to evaluate the effect of treatment with choline or cytidine-5'-diphosphocholine (CDP-choline), a choline donor, on endotoxin-induced hemostatic alterations using thromboelastography (TEG). Dogs were randomized to six groups and received intravenously (iv) saline, choline (20 mg/kg) or CDP-choline (70 mg/kg) in the control groups, whereas endotoxin (0.1 mg/kg, iv) was used alone or in combination with choline or CDP-choline at the same doses in the treatment groups. TEG variables including R- and K-time (clot formation), maximum amplitude (MA) and α-angle (clot stability), G value (clot elasticity), and EPL, A, and LY30 (fibrinolysis), as well as overall assessment of coagulation (coagulation index - CI), were measured before and at 0.5-48 h after the treatments. TEG parameters did not change significantly in the control groups, except for CI parameter after choline administration. Endotoxemia resulted in increased R-time and A value (P < 0.05), decreased K-time (P < 0.05), α-angle (P < 0.001) and CI values (P < 0.01) at different time points. Treatment with either choline or CDP-choline attenuated or prevented completely the alterations in TEG parameters in endotoxemic dogs with CDP-choline being more effective. These results confirm and extend the effectiveness of choline or CDP-choline in endotoxemia by further demonstrating their efficacy in attenuating or preventing the altered viscoelastic properties of blood clot measured by TEG.

Choline supplementation attenuates experimental sepsis-associated acute kidney injury

Acute kidney injury (AKI) is common in critically ill patients, and sepsis is its leading cause. Sepsis-associated AKI (SA-AKI) causes greater morbidity and mortality than other AKI etiologies, yet the underlying mechanisms are incompletely understood. Metabolomic technologies can characterize cellular energy derangements, but few discovery analyses have evaluated the metabolomic profile of SA-AKI. To identify metabolic derangements amenable to therapeutic intervention, we assessed plasma and urine metabolites in septic mice and critically ill children and compared them by AKI status. Metabolites related to choline and central carbon metabolism were differentially abundant in SA-AKI in both mice and humans. Gene expression of enzymes related to choline metabolism was altered in the kidneys and liver of mice with SA-AKI. Treatment with intraperitoneal choline improved renal function in septic mice. Because pediatric patients with sepsis displayed similar metabolomic profiles to septic mice, choline supplementation may attenuate pediatric septic AKI.NEW & NOTEWORTHY Altered choline metabolism plays a role in both human and murine sepsis-associated acute kidney injury (SA-AKI), and choline administration in experimental SA-AKI improved renal function. These findings indicate that 1) mouse models can help interrogate clinically relevant mechanisms and 2) choline supplementation may ameliorate human SA-AKI. Future research will investigate clinically the impact of choline supplementation on human renal function in sepsis and, using model systems, how choline mediates its effects.

Choline or CDP-choline restores hypotension and improves myocardial and respiratory functions in dogs with experimentally - Induced endotoxic shock

Endotoxin shock is associated with severe impairments in cardiovascular and respiratory functions. We showed previously that choline or cytidine-5'-diphosphocholine (CDP-choline) provides beneficial effects in experimental endotoxin shock in dogs. The objective of the present study was to determine the effects of choline or CDP-choline on endotoxin-induced cardiovascular and respiratory dysfunctions. Dogs were treated intravenously (i.v.) with saline or endotoxin (LPS, 0.1 mg/kg) 5 min before i.v. infusion of saline, choline (20 mg/kg) or CDP-choline (70 mg/kg). Blood pressure, cardiac rate, myocardial and left ventricular functions, respiratory rate, blood gases, serum electrolytes and cardiac injury markers were determined before and at 0.5-48 h after endotoxin. Plasma tumor necrosis factor alpha (TNF-α), high mobility group box-1 (HMGB1), catecholamine and nitric oxide (NO) levels were measured 2 h and 24 h after the treatments. Endotoxin caused immediate and sustained reductions in blood pressure, cardiac output, pO₂ and pH; changes in left ventricular functions, structure and volume parameters; and elevations in heart rate, respiratory rate, pCO2 and serum electrolytes (Na, K, Cl, Ca and P). Endotoxin also resulted in elevations in blood levels of cardiac injury markers, TNF-α, HMGB1, catecholamine and NO. In choline- or CDP-choline-treated dogs, all endotoxin effects were much smaller in magnitude and shorter in duration than observed values in controls. These data show that treatment with choline or CDP-choline improves functions of cardiovascular and respiratory systems in experimental endotoxemia and suggest that they may be useful in treatment of endotoxin shock in clinical setting.

Cholinergic modulation of the immune system - A novel therapeutic target for myocardial inflammation

The immune system and the nervous system depend on each other for their fine tuning and working, thus cooperating to maintain physiological homeostasis and prevent infections. The cholinergic system regulates the mobilization, differentiation, secretion, and antigen presentation of adaptive and innate immune cells mainly through α7 nicotinic acetylcholine receptors (α7nAChRs). The neuro-immune interactions are established and maintained by the following mechanisms: colocalization of immune and neuronal cells at defined anatomical sites, expression of the non-neuronal cholinergic system by immune cells, and the acetylcholine receptor-mediated activation of intracellular signaling pathways. Based on these immunological mechanisms, the protective effects of cholinergic system in animal models of diseases were summarized in this paper, such as myocardial infarction/ischemia-reperfusion, viral myocarditis, and endotoxin-induced myocardial damage. In addition to maintaining hemodynamic stability and improving the energy metabolism of the heart, both non-neuronal acetylcholine and neuronal acetylcholine in the heart can alleviate myocardial inflammation and remodeling to exert a significant cardioprotective effect. The new findings on the role of cholinergic agonists and vagus nerve stimulation in immune regulation are updated, so as to develop improved approaches to treat inflammatory heart disease.

Nasal secretory protein changes following intravenous choline administration in calves with experimentally induced endotoxaemia

Nasal secretory fluid proteomes (NSPs) can provide valuable information about the physiopathology and prognosis of respiratory tract diseases. This study aimed to determine changes in NSP by using proteomics in calves treated with lipopolysaccharide (LPS) or LPS + choline. Healthy calves (n = 10) were treated with LPS (2 μg/kg/iv). Five minutes after LPS injection, the calves received a second iv injection with saline (n = 5, LPS + saline group) or saline containing 1 mg/kg choline (n = 5, LPS + choline group). Nasal secretions were collected before (baseline), at 1 h and 24 h after the treatments and analysed using label-free liquid chromatography-tandem mass spectrometry (LCMS/MS). Differentially expressed proteins (>1.2-fold-change) were identified at the different time points in each group. A total of 52 proteins were up- and 46 were downregulated at 1 h and 24 h in the LPS + saline group. The upregulated proteins that showed the highest changes after LPS administration were small ubiquitin-related modifier-3 (SUMO3) and glutathione peroxidase-1 (GPX1), whereas the most downregulated protein was E3 ubiquitin-protein ligase (TRIM17). Treatment with choline reduced the number of upregulated (32 proteins) and downregulated proteins (33 proteins) in the NSPs induced by LPS. It can be concluded that the proteome composition of nasal fluid in calves changes after LPS, reflecting different pathways, such as the activation of the immunological response, oxidative stress, ubiquitin pathway, and SUMOylation. Choline treatment alters the NSP response to LPS.

Changes in choline and cholinesterase in saliva of dogs with parvovirus infection

This study investigated the changes in choline (Ch) and butyrylcholinesterase (BChE) in saliva in canine parvovirosis (CP) as a model of sepsis, and their correlations with these analytes in serum and with other markers of inflammation such as white blood cell count (WBC) and serum C-reactive protein (CRP). A total of 30 dogs with CP were sampled for saliva and serum at presentation, and 10 healthy puppies were also sampled as controls. Salivary Ch was higher in dogs with CP (P < 0.001) showing a positive correlation with CRP, whereas no differences were observed in salivary BChE. This is the first report in which Ch is measured in saliva of dogs and based in the results of this study, salivary Ch could be potentially used as biomarker of the severity of CP.

Choline: An Essential Nutrient for Skeletal Muscle

BACKGROUND

Choline is an essential micronutrient with a pivotal role in several metabolic pathways contributing to liver, neurological, and hematological homeostasis. Although choline is commonly administered to improve physical performance, its effects on muscle are still unclear. The aim of this scoping review is to analyze the role of choline on skeletal muscle in terms of biological effects and clinical implications.

METHODS

A technical expert panel (TEP) of 6 medical specialists with expertise in muscle physiology and skeletal muscle disorders performed the review following the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model. The TEP planned a research on PubMed selecting "choline" as MeSH (Medical Subject Headings) term adding to PubMed Search Builder the terms "skeletal muscle" and "muscle striated". TEP considered for eligibility articles published in the last 30 years, including original researches, particularly in vitro studies, and animal and clinical studies in the English language.

RESULTS

From the 1239 studies identified, TEP included 14 studies, 3 in vitro, 9 animal, and 2 clinical studies.

CONCLUSIONS

Our scoping review elucidates and summarizes the crucial role of choline in modulating muscle fat metabolism, muscle proteins homeostasis, and the modulation of inflammation and autophagy.

Serum choline and butyrylcholinesterase changes in response to endotoxin in calves receiving intravenous choline administration

Endotoxemia treatment options are still of interest due to high mortality and choline treatment is one of them because of its role in the cholinergic anti-inflammatory pathway. This study investigated serum choline and butyrylcholinesterase (BChE) responses, and their correlations with inflammatory, oxidative stress and tissue damage biomarkers, including paraoxanase-1 (PON1), and clinical signs in calves with endotoxemia and the effect of choline treatment in these responses. Healthy calves (n = 20) were divided equally into 4 groups: Control (0.9% NaCl, iv), Choline (C; 1 mg/kg/iv,once), Lipopolysaccharide (LPS; 2 μg/kg/iv,once) and LPS + C. Clinical and laboratory examinations were performed before and 0.5-48 h (hrs) after treatments. Following LPS administration, serum choline level increased at 0.5-24 h (P < .01), whereas serum BChE and PON1 level decreased at 48 h (P < .01) compared to their baselines. In LPS + C group, the increase in serum choline level was significantly higher (P < .01) than that of C and LPS groups. LPS did not decrease serum BChE levels significantly in calves treated with choline. Serum choline and BChE results correlated negatively with white blood cell count and positively (P < .001) with PON1 levels, oxidative stress index, inflammation and hepato-muscular injury markers. In conclusion serum choline and BChE may have a role in the pathophysiology of endotoxemia in calves. High serum choline concentration is associated with an improvement in response to LPS administration in calves treated with choline, probably by preventing the imbalances between oxidative stress and anti-oxidant capacity, preventing the serum BChE and PON1 decreases, and inhibition/attenuation of acute phase reaction and hepato-muscular injury in calves with endotoxemia.

Choline and Choline alphoscerate Do Not Modulate Inflammatory Processes in the Rat Brain

Choline is involved in relevant neurochemical processes. In particular, it is the precursor and metabolite of acetylcholine (ACh). Choline is an essential component of different membrane phospholipids that are involved in intraneuronal signal transduction. On the other hand, cholinergic precursors are involved in ACh release and carry out a neuroprotective effect based on an anti-inflammatory action. Based on these findings, the present study was designed to evaluate the effects of choline and choline precursor (Choline alphoscerate, GPC) in the modulation of inflammatory processes in the rat brain. Male Wistar rats were intraperitoneally treated with 87 mg of choline chloride/kg/day (65 mg/kg/day of choline), and at choline-equivalent doses of GPC (150 mg/kg/day) and vehicle for two weeks. The brains were dissected and used for immunochemical and immunohistochemical analysis. Inflammatory cytokines (Interleukin-1β, IL-1β; Interleukin-6, IL-6 and Tumor Necrosis Factor-α, TNF-α) and endothelial adhesion molecules (Intercellular Adhesion Molecule, ICAM-1 and Vascular cell Adhesion Molecule, VCAM-1) were studied in the frontal cortex, hippocampus, and cerebellum. The results clearly demonstrated that treatment with choline or GPC did not affect the expression of the inflammatory markers in the different cerebral areas evaluated. Therefore, choline and GPC did not stimulate the inflammatory processes that we assessed in this study.

Choline ameliorates cardiovascular damage by improving vagal activity and inhibiting the inflammatory response in spontaneously hypertensive rats

Autonomic dysfunction and abnormal immunity lead to systemic inflammatory responses, which result in cardiovascular damage in hypertension. The aim of this report was to investigate the effects of choline on cardiovascular damage in hypertension. Eight-week-old male spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats were intraperitoneally injected with choline or vehicle (8 mg/kg/day). After 8 weeks, choline restored the cardiac function of the SHRs, as evidenced by decreased heart rate, systolic blood pressure, left ventricle systolic pressure, and ±dp/dt_max and increased ejection fraction and fractional shortening. Choline also ameliorated the cardiac hypertrophy of the SHRs, as indicated by reduced left ventricle internal dimensions and decreased cardiomyocyte cross-sectional area. Moreover, choline improved mesenteric arterial function and preserved endothelial ultrastructure in the SHRs. Notably, the protective effect of choline may be due to its anti-inflammatory effect. Choline downregulated expression of interleukin (IL)-6 and tumour necrosis factor-α and upregulated IL-10 in the mesenteric arteries of SHRs, possibly because of the inhibition of Toll-like receptor 4. Furthermore, choline restored baroreflex sensitivity and serum acetylcholine level in SHRs, thus indicating that choline improved vagal activity. This study suggests that choline elicits cardiovascular protective effects and may be useful as a potential adjunct therapeutic approach for hypertension.

Changes in serum proteins after endotoxin administration in healthy and choline-treated calves

BACKGROUND

This study aimed to investigate the possible serum protein changes after endotoxin administration in healthy and choline-treated calves using proteomics. These results are expected to contribute to the understanding of the pathophysiological mechanisms of endotoxemia and the beneficial effect of choline administration in this clinical situation.

METHODS

Healthy-calves (n = 20) were divided into 4 groups: Control, Choline treated (C), Lipopolysaccharide administered (LPS), and LPS + C. Control calves received 0.9 % NaCl injection. Calves in C and LPS + C groups received choline chloride (1 mg/kg/iv). Endotoxin (LPS) was injected (2 μg/kg/iv) to the calves in LPS and LPS + C groups. Serum samples were collected before and after the treatments. Differentially expressed proteins (> 1.5 fold-change relative to controls) were identified by LC-MS/MS.

RESULTS

After LPS administration, 14 proteins increased, and 13 proteins decreased within 48 h as compared to controls. In the LPS group, there were significant increases in serum levels of ragulator complex protein (189-fold) and galectin-3-binding protein (10-fold), but transcription factor MafF and corticosteroid binding globulin were down regulated (≥ 5 fold). As compared with the LPS group, in LPS + C group, fibrinogen gamma-B-chain and antithrombin were up-regulated, while hemopexin and histone H4 were down-regulated. Choline treatment attenuated actin alpha cardiac muscle-1 overexpression after LPS.

CONCLUSIONS

LPS administration produces changes in serum proteins associated with lipid metabolism, immune and inflammatory response, protein binding/transport, cell adhesion, venous thrombosis, cardiac contractility and blood coagulation. The administration of choline is associated with changes in proteins which can be related with its beneficial effect in this clinical situation.

Effects of choline treatment in concentrations of serum matrix metalloproteinases (MMPs), MMP tissue inhibitors (TIMPs) and immunoglobulins in an experimental model of canine sepsis

The aim of the present study was to investigate effects of intravenous (i.v.) choline treatment on serum matrix metalloproteinases (MMP), MMP tissue inhibitors (TIMP) and immunoglobulins (Igs), and to determine if there were relations between serum MMPs/TIMPs and C-reactive protein (CRP) (as a marker of the acute phase response), immunoglobulin G and M (IgG and IgM) (as a maker of the Ig responses) and markers of organ damage such as muscular damage (creatine phosphokinase, [CPK]), liver damage (alanine aminotransferase [ALT]) and renal dysfunction (blood urea nitrogen [BUN] and creatinine, [Cr]) in dogs with endotoxemia. Healthy dogs (n=24) were randomized to Saline, Choline (C), Lipopolysaccharide (LPS), and LPS+C groups and received 0.9% NaCl (5mL/i.v.), choline chloride (20mg/kg/i.v.), LPS (0.02mg/kg/i.v.) and LPS (0.02mg/kg/i.v.) plus choline chloride (20mg/kg/i.v.), respectively. Serum MMPs and TIMPs concentrations were analyzed by commercial ELISA kits. MMP and TIMP increased at 1-48h (P<0.05), whereas IgG and IgM decreased at 24-48h in LPS group, compared to their baselines. Choline treatment reduced changes in serum MMPs, TIMPs and markers of organ damage, and prevented the hypoimmunoglobulinemia in LPS+C. MMPs and TIMPs were correlated positively (P<0.05) with serum CRP, CPK, ALT, BUN and Cr, but not with serum Igs. Our findings suggest that the serum MMPs, TIMPs and Igs are involved in the pathophysiology of endotoxemia, and MMPs and TIMPs are correlated with the acute phase reaction and multi-organ failure. In addition, we demonstrated a direct effect of choline administration in decreasing serum MMPs and TIMPs, and preserving serum Igs in the course of endotoxemia.

Influence of Cdp-Choline Administration on Early Burn Edema in Rats

PURPOSE

The cholinergic anti-inflammatory pathway may play an important role in early burn edema. Therefore, we evaluated the influence of cdp-choline on early systemic burn edema and leukocyte activation in shock in rat mesenteries after burn plasma transfer.

METHODS

Burn plasma harvested from donor rats 4 hours after thermal injury (30% total body surface area, 100°C water, 12 seconds) was administered intravenously to healthy animals during 2 hours of intravital microscopy. Shamburn plasma (same procedure but water at 37°C) was transferred for negative controls. In the study group, bolus injection of 100 mg/kg body weight cdp-choline was undertaken 15 minutes before examination. Intravital microscopy was performed in the ileal portion of rat mesenteries at 0, 60, and 120 minutes. Capillary leakage was assessed by fluorescein isothiocyanate-albumin extravasation and leukocyte-endothelial interaction were observed via transillumination microscopy. To assure comparable hemodynamic conditions, microhemodynamic parameters, foremost venular wall shear rate, were assessed.

RESULTS

Capillary leakage increased significantly after burn plasma transfer when compared to the shamburn group. Additional intravenous administration of cdp-choline attenuates macromolecular efflux to shamburn levels. Leukocyte activation is reduced after cdp-choline treatment.

CONCLUSIONS

The significant increase of albumin efflux in rat mesenteries after burn plasma transfer is decreased by additional cdp-choline bolus administration. Further investigations for proof of the relevance of the cholinergic anti-inflammatory pathway in early burn trauma are strongly required.

Cytidine 5'-diphosphocholine administration prevents peripheral neuropathic pain after sciatic nerve crush injury in rats

Background

Cytidine 5′-diphosphocholine (citicoline) has been shown to have beneficial effects in central nervous system injury as well as in motoric functional recovery after peripheral nerve injury. This study aimed to examine the effect of citicoline on prevention of neuropathic pain in a rat model of sciatic nerve crush injury.

Methods

Forty experimental rats were divided into four groups. In three groups, the right sciatic nerves were crushed in the mid-thigh region, and a gelatin sponge moistened with 0.4 or 0.8 mL of 100 µmol/L citicoline, or saline 0.4 mL in the control group, was applied. The fourth group of rats was sham-operated, ie the sciatic nerve was exposed with no crush. Functional assessments were performed 4 weeks after crush injury. von Frey filaments (100 g threshold) were used to assess neuropathic pain. In addition, the sciatic functional index and extensor postural thrust (EPT) tests were used to assess motoric function.

Results

The crush/citicoline 0.4 mL group had a lower percentage of pain (23.53%, n=17) compared with the crush/saline group (53.33%, n=15, P<0.005). The crush/citicoline 0.4 mL group also showed better motoric recovery, as seen in stronger EPT results (P<0.001). However, the sciatic functional index analysis did not show significant differences between groups (P=0.35). The crush/citicoline 0.8 mL group showed a higher percentage of pain (66.67%, n=18) and less EPT recovery. These results may be explained by more severe nerve injury due to compression with a larger administered volume.

Conclusion

In situ administration of 0.4 mL of 100 µmol/L citicoline prevents the occurrence of neuropathic pain and induces motoric recovery, evaluated by EPT test, 4 weeks after sciatic nerve injury.

Cytidine 5'-diphosphocholine ameliorates hyperoxic lung injury in a neonatal rat model

BACKGROUND

Bronchopulmonary dysplasia (BPD) is an important cause of morbidity. The aim of this study was to evaluate the preventive effect of cytidine 5'-diphosphocholine (CDP-choline) treatment on hyperoxic lung injury in a neonatal rat model.

METHODS

A total of 30 newborn pups were divided into control, hyperoxia, and hyperoxia + CDP-choline groups. After birth, pups in the control group were kept in room air and received saline injections, whereas those in hyperoxia and hyperoxia + CDP-choline groups were exposed to 95% O₂ and received daily injections of saline and CDP-choline throughout postnatal day 10, respectively. Histopathological scoring, radial alveolar count, lamellar body membrane protein expression, fibrosis, proinflammatory cytokine levels, lung tissue and bronchoalveolar lavage (BAL) fluid phospholipid content, and apoptosis were evaluated.

RESULTS

Hyperoxia-induced severe lung damage was reduced significantly by CDP-choline treatment. Radial alveolar count and lamellar body membrane protein expression were significantly recovered, and the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive cells, active caspase-3 expression, and tissue proinflammatory cytokine levels were decreased by CDP-choline administration. Lung tissue and BAL phospholipid contents showed significant increases after CDP-choline administration.

CONCLUSION

These data show that CDP-choline ameliorates hyperoxic lung injury in a neonatal rat model. It may therefore be suggested that CDP-choline may be a novel therapeutic option for the prevention of BPD.

CDP-choline reduces severity of intestinal injury in a neonatal rat model of necrotizing enterocolitis

BACKGROUND

Cytidine 5'-diphosphocholine (CDP-choline) is an endogenous intermediate in the biosynthesis of phosphatidylcholine, a contributor to the mucosal defense of the intestine. The aim of this study was to evaluate the possible cytoprotective effect of CDP-choline treatment on intestinal cell damage, membrane phospholipid content, inflammation, and apoptosis in a neonatal rat model of necrotizing enterocolitis (NEC).

METHODS

We divided a total of 30 newborn pups into three groups: control, NEC, and NEC + CDP-choline. We induced NEC by enteral formula feeding, exposure to hypoxia-hyperoxia, and cold stress. We administered CDP-choline intraperitoneally at 300 mg/kg/d for 3 d starting from the first day of life. We evaluated apoptosis macroscopically and histopathologically in combination with proinflammatory cytokines in the gut samples. Moreover, we determined membrane phospholipid levels as well as activities of xanthine oxidase, superoxide dismutase, glutathione peroxidase, and myeloperoxidase enzymes and the malondialdehyde content of intestinal tissue.

RESULTS

Mean clinical sickness score, macroscopic gut assessment score, and intestinal injury score were significantly improved, whereas mean apoptosis score and caspase-3 levels were significantly reduced in pups in the NEC + CDP-choline group compared with the NEC group. Tissue proinflammatory cytokine (interleukin-1β, interleukin-6, and tumor necrosis factor-α) levels as well as tissue malondialdehyde content and myeloperoxidase activities were reduced, whereas glutathione peroxidase and superoxide dismutase activities were preserved in the NEC + CDP-choline group. In addition, NEC damage reduced intestinal tissue membrane phospholipids, whereas CDP-choline significantly enhanced total phospholipid and phosphatidylcholine levels. Long-term follow-up in additional experiments revealed increased body weight, decreased clinical sickness scores, and enhanced survival in CDP-choline-receiving versus saline-receiving pups with NEC lesions.

CONCLUSIONS

Our study reports, for the first time, beneficial effects of CDP-choline treatment on intestinal injury in a neonatal rat model of NEC. Our data suggest that CDP-choline may be used as an effective therapeutic agent to prevent NEC.

Choline or CDP-choline attenuates coagulation abnormalities and prevents the development of acute disseminated intravascular coagulation in dogs during endotoxemia

Sepsis/endotoxemia causes platelet dysfunctions, abnormalities in coagulation and hemostatic mechanisms leading to organ dysfunctions and mortality. Choline prevents organ injury and improves survival during endotoxemia. The main objective of the present study was to determine the effects of choline or cytidine-5'-diphosphocholine (CDP-choline) on endotoxin-induced activation of coagulation and development of disseminated intravascular coagulation (DIC). Dogs were treated intravenously (i.v.) with saline, choline (20 mg/kg), or CDP-choline (70 mg/kg) three times with 4-h intervals starting 5 min before i.v. injection of endotoxin (1 mg/kg). Platelet counts and functions, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, coagulation factors, D-dimer and antithrombin (AT) were measured before and at 0.5-96 h after endotoxin. Circulating platelet, fibrinogen, coagulation factors and AT were decreased, whereas PT and aPTT were prolonged and serum D-dimer levels were elevated after endotoxin. Endotoxin-induced reductions in platelet counts and functions, fibrinogen, coagulation factors and AT were attenuated or blocked by choline or CDP-choline. Choline or CDP-choline blocked endotoxin-induced prolongation in PT and aPTT and enhancement in D-dimer. Elevated DIC scores were attenuated by choline and blocked by CDP-choline. Choline administration increased serum choline concentrations and caused bradycardia. Choline also increased choline and acetylcholine contents of circulating mononuclear cells and inhibited radioligand binding to their cholinergic receptors. These data show that choline administration, as choline chloride or CDP-choline, restores the abnormalities in the primary, secondary, and tertiary hemostasis and prevents the development of DIC during experimental endotoxemia in dogs probably by increasing both neuronal and non-neuronal cholinergic activity.

Choline or CDP-choline alters serum lipid responses to endotoxin in dogs and rats: involvement of the peripheral nicotinic acetylcholine receptors

We showed previously that choline administration protects dogs from endotoxin-induced multiple organ injury and platelet dysfunctions. Because sepsis/endotoxemia is associated with alterations in lipid metabolism, we have investigated whether choline or cytidine-5'-diphosphate choline, a choline donor, alters serum lipid responses to endotoxin in dogs and rats. In response to endotoxin, serum concentrations of triglycerides, choline-containing phospholipids, total cholesterol, and high-density lipoprotein cholesterol increased in a dose- and time-related manner. Administration of choline (20 mg/kg i.v. in dogs or 90 mg/kg i.p. in rats) or cytidine-5'-diphosphate choline (70 mg/kg i.v. in dogs) 5 min before and 4 and 8 h after endotoxin blocked or attenuated the increases in serum triglycerides, total cholesterol, and nonesterified fatty acids. Endotoxin-induced elevations in serum phospholipid levels did not change in rats and were enhanced in dogs by choline. In rats, serum lipid response to endotoxin was accompanied by severalfold elevations in serum levels of hepatorenal injury markers; their elevations were also blocked by choline. Pretreatment with hexamethonium blocked choline's effects on serum lipids and hepatorenal injury markers. Pretreatment with atropine blocked endotoxin-induced elevations in serum lipid and hepatorenal injury markers, but failed to alter choline's actions on these parameters. Choline treatment improved survival rate of rats in lethal endotoxin shock. In conclusion, these data show that choline treatment alters serum lipid responses to endotoxin and prevents hepatorenal injury during endotoxemia through a nicotinic acetylcholine receptor-mediated mechanism. Hence, choline and choline-containing compounds may have a therapeutic potential in the treatment of endotoxemia/sepsis.

TNF-alpha-induced up-regulation of pro-inflammatory cytokines is reduced by phosphatidylcholine in intestinal epithelial cells

Background

Phosphatidylcholine (PC) is a major lipid of the gastrointestinal mucus layer. We recently showed that mucus from patients suffering from ulcerative colitis has low levels of PC. Clinical studies reveal that the therapeutic addition of PC to the colonic mucus using slow release preparations is beneficial. The positive role of PC in this disease is still unclear; however, we have recently shown that PC has an intrinsic anti-inflammatory property. It could be demonstrated that the exogenous application of PC inhibits membrane-dependent actin assembly and TNF-α-induced nuclear NF-κB activation. We investigate here in more detail the hypothesis that the exogenous application of PC has anti-inflammatory properties.

Methods

PC species with different fatty acid side chains were applied to differentiated and non-differentiated Caco-2 cells treated with TNF-α to induce a pro-inflammatory response. We analysed TNF-α-induced NF-κB-activation via the transient expression of a NF-κB-luciferase reporter system. Pro-inflammatory gene transcription was detected with the help of a quantitative real time (RT)-PCR analysis. We assessed the binding of TNF-α to its receptor by FACS and analysed lipid rafts by isolating detergent resistant membranes (DRMs).

Results

The exogenous addition of all PC species tested significantly inhibited TNF-α-induced pro-inflammatory signalling. The expression levels of IL-8, ICAM-1, IP-10, MCP-1, TNF-α and MMP-1 were significantly reduced after PC pre-treatment for at least two hours. The effect was comparable to the inhibition of NF-kB by the NF-kB inhibitor SN 50 and was not due to a reduced binding of TNF-α to its receptor or a decreased surface expression of TNF-α receptors. PC was also effective when applied to the apical side of polarised Caco-2 cultures if cells were stimulated from the basolateral side. PC treatment changed the compartmentation of the TNF-α-receptors 1 and 2 to DRMs.

Conclusion

PC induces a prolonged inhibition of TNF-α-induced pro-inflammatory signalling. This inhibition may be caused by a shift of the TNF-α receptors at the surface to lipid rafts. Our results may offer a potential molecular explanation for the positive role of PC seen in clinical studies for the treatment of ulcerative colitis.

Cholinergic control of inflammation

Cytokine production is necessary to protect against pathogens and promote tissue repair, but excessive cytokine release can lead to systemic inflammation, organ failure and death. Inflammatory responses are finely regulated to effectively guard from noxious stimuli. The central nervous system interacts dynamically with the immune system to modulate inflammation through humoral and neural pathways. The effect of glucocorticoids and other humoral mediators on inflammatory responses has been studied extensively in the past decades. In contrast, neural control of inflammation has only been recently described. We summarize autonomic regulation of local and systemic inflammation through the 'cholinergic anti-inflammatory pathway', a mechanism consisting of the vagus nerve and its major neurotransmitter, acetylcholine, a process dependent on the nicotinic acetylcholine receptor alpha7 subunit. We recapitulate additional sources of acetylcholine and their contribution to the inflammatory response, as well as acetylcholine regulation by acetylcholinesterase as a means to attenuate inflammation. We discuss potential therapeutic applications to treat diseases characterized by acute or chronic inflammation, including autoimmune diseases, and propose future research directions.

Oral phosphatidylcholine pretreatment decreases ischemia-reperfusion-induced methane generation and the inflammatory response in the small intestine

We have shown that phosphatidylcholine (PC) metabolites may have a function in counteracting the production of reactive oxygen species (ROS), and that this mechanism can lead to the generation of methane from choline. The aims were to establish whether the dietary administration of PC can protect the reperfused small bowel mucosa by its acting as an anti-inflammatory agent and to investigate this possibility in association with in vivo methane generation. Group 1 (n = 5) of anesthetized dogs served as sham-operated controls, whereas in groups 2 (n = 6) and 3 (n = 6), complete small intestinal ischemia was induced by occluding the superior mesenteric artery for 60 min. Groups 1 and 2 were fed with normal laboratory chow for 1 week before the experiments, whereas the animals in group 3 received a special diet containing 1% soybean PC. The intramucosal pH and the difference of the arterial and local PCO2 (PCO2 gap) were detected by indirect tonometry. Intestinal superoxide production and myeloperoxidase (MPO) activity (a marker of tissue leukocyte infiltration) were ascertained on ileal biopsy samples 180 min after reperfusion. The content of methane in the exhaled air was determined by gas chromatography. I/R was characterized by significant tissue acidosis with ROS generation and elevated MPO activity. These changes were accompanied by increased methane production in the exhaled air during reoxygenation. The PC-enriched diet prevented the decrease in intramucosal pH, diminished the intestinal superoxide generation and the MPO activity, and significantly decreased the exhaled methane concentration. The increased dietary uptake of PC exerts an anti-inflammatory influence in the gastrointestinal tract. Exhaled methane is linked to abnormal ROS generation; a decreased methane production is associated with significantly reduced inflammatory activation during I/R.

Modulation of TNF release by choline requires alpha7 subunit nicotinic acetylcholine receptor-mediated signaling

The alpha7 subunit-containing nicotinic acetylcholine receptor (alpha7nAChR) is an essential component in the vagus nerve-based cholinergic anti-inflammatory pathway that regulates the levels of TNF, high mobility group box 1 (HMGB1), and other cytokines during inflammation. Choline is an essential nutrient, a cell membrane constituent, a precursor in the biosynthesis of acetylcholine, and a selective natural alpha7nAChR agonist. Here, we studied the anti-inflammatory potential of choline in murine endotoxemia and sepsis, and the role of the alpha7nAChR in mediating the suppressive effect of choline on TNF release. Choline (0.1-50 mM) dose-dependently suppressed TNF release from endotoxin-activated RAW macrophage-like cells, and this effect was associated with significant inhibition of NF-kappaB activation. Choline (50 mg/kg, intraperitoneally [i.p.]) treatment prior to endotoxin administration in mice significantly reduced systemic TNF levels. In contrast to its TNF suppressive effect in wild type mice, choline (50 mg/kg, i.p.) failed to inhibit systemic TNF levels in alpha7nAChR knockout mice during endotoxemia. Choline also failed to suppress TNF release from endotoxin-activated peritoneal macrophages isolated from alpha7nAChR knockout mice. Choline treatment prior to endotoxin resulted in a significantly improved survival rate as compared with saline-treated endotoxemic controls. Choline also suppressed HMGB1 release in vitro and in vivo, and choline treatment initiated 24 h after cecal ligation and puncture (CLP)-induced polymicrobial sepsis significantly improved survival in mice. In addition, choline suppressed TNF release from endotoxin-activated human whole blood and macrophages. Collectively, these data characterize the anti-inflammatory efficacy of choline and demonstrate that the modulation of TNF release by choline requires alpha7nAChR-mediated signaling.

Endotoxin increases plasma leptin and ghrelin levels in dogs

OBJECTIVE

Evaluations of plasma leptin and ghrelin levels and their relations with circulating levels of proinflammatory mediators, stress hormones, and biochemical markers of hepatorenal injury during experimental endotoxemia in dogs.

SETTING

Uludag University.

DESIGN

Placebo-controlled animal study.

ANIMALS

Adult mongrel dogs (n = 16).

INTERVENTIONS

Intravenous injection of endotoxin (1 mg/kg) and blood sample withdrawal before and at 0.5-48 hrs posttreatment.

MEASUREMENTS AND MAIN RESULTS

Mean baseline plasma leptin and ghrelin levels were 2.4 +/- 0.1 ng/mL and 867 +/- 58 pg/mL, respectively. Plasma leptin and ghrelin increased significantly by 16% (p < .05) and 72% (p < .001) at 0.5 hr, and they remained elevated by 33-41% (p < .001) and 59-74% (p < .001) at 48 hrs after administration of endotoxin, respectively. There was positive correlation (r = .844; p < .001) between plasma leptin and ghrelin levels in endotoxin-treated dogs. Endotoxemia was associated with several-fold elevations in circulating levels of stress hormones, proinflammatory mediators, and hepatorenal injury markers. Plasma leptin and ghrelin levels in endotoxin-treated dogs were correlated with serum nitric oxide (r = .955 and r = .890; p < .001), procalcitonin (r = .825 and r = .716; p < .001), cortisol (r = .823 and r = .786; p < .001), and hepatorenal injury markers (r = .580 to .745 and r = .393 to .574; p < .05 to .01).

CONCLUSIONS

Circulating leptin and ghrelin levels increase during endotoxemia, and these increases are associated with elevated levels of proinflammatory mediators, stress hormones, and serum biochemical markers for hepatorenal dysfunction.

Greater hypoxia-induced cell death in prenatal brain after bacterial-endotoxin pretreatment is not because of enhanced cerebral energy depletion: a chicken embryo model of the intrapartum response to hypoxia and infection

Infection is a risk factor for adult stroke and neonatal encephalopathy. We investigated whether exposure to bacterial endotoxin increases hypoxia-induced brain cell death and impairs cerebral metabolic compensatory responses to hypoxia. Prehatching chicken embryos (incubation day 19) were exposed to bacterial lipopolysaccharide (LPS) (3 mg Salmonella typhimurium LPS per egg) or hypoxia (4% ambient O(2) for 1 h), alone or in combination with LPS, followed 4 h later by hypoxia. Cerebral cell death and glial activation were assessed histologically. Further, chicken embryo brains were studied by magnetic resonance imaging (MRI) and spectroscopy (MRS) to assess haemodynamic and metabolic responses. In most brain areas, combined LPS/hypoxia resulted in a 30- to 100-fold increase in terminal deoxynucleotidyl transferase dUTP nick end labelling -positive cells, compared to control and single-insult groups. Glial activation correlated with the severity of cell death and was significantly greater in the combined-insult group (P<0.05). Hypoxia was associated with a 10-fold increase in lactate/N-acetyl-aspartate (NAA), an approximately 20% increase in total creatine/NAA, rapid decreases in T2 and T2(*), and a reduction in direction-averaged brain-water diffusion (D(av)) by approximately 15%. Liposaccharide pretreatment did not alter the magnitude or timing of these responses, but engendered baseline shifts (increased Cho/NAA, Cr/NAA, and Dav, and reduced T2(*)). In conclusion, LPS greatly increased hypoxia-induced brain damage in this model and induced changes in baseline haemodynamics and metabolism but did not affect the magnitude of the glycolytic response to hypoxia. The damage-enhancing effects of LPS are not because of additional energy depletion but because of a synergistic toxic component.

Characterisation of lipid profiles in dogs with parvoviral enteritis

OBJECTIVE

To characterise the lipid profiles in dogs with parvoviral enteritis.

METHODS

Blood was collected before treatment from 30 dogs that fulfilled the criteria for severe sepsis including hypo- or hyperthermia, hypotension, leucopenia, thrombocytopenia and evidences of organ dysfunction. Canine parvovirus was detected by haemagglutination and indirect fluorescence antibody tests in the faeces. Twenty control dogs were also enrolled on the basis of normal physical examination results, complete blood count and serum biochemistry profiles.

RESULTS

Tachycardia, tachypnoea, hypotension, leucopenia, thrombocytopenia and increased serum markers of tissue injury (alanine aminotransferase, creatinine kinase myocardial isoenzyme [CK-MB], blood urea nitrogen and creatinine) were observed in dogs with parvoviral enteritis. Serum total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol levels were lower, but serum triglyceride level was higher in dogs with parvoviral enteritis than those in control dogs (P<0.001). Circulating tumour necrosis factor alpha correlated negatively with total cholesterol (r=-0.979; P<0.001) but positively with triglyceride (r=0.953; P<0.001) in dogs with parvoviral enteritis. Serum total cholesterol and high-density lipoprotein cholesterol levels were lower in non-survival (n=9) dogs than in survival dogs (n=21, P<0.001).

CLINICAL SIGNIFICANCE

Serum total cholesterol and high-density lipoprotein cholesterol levels decreased, but serum triglyceride level increased in dogs with parvoviral enteritis. Low serum total cholesterol and high-density lipoprotein cholesterol levels may be used as an index of the severity of parvoviral enteritis.

Serum leptin and ghrelin levels in response to methylprednisolone injection in healthy dogs

The aim of this study was to investigate the effects of methylprednisolone treatment on serum leptin and ghrelin levels in healthy dogs (n=40). After 14 h of fasting, the dogs were injected intramuscularly with saline (control group) or methylprednisolone (1, 5 or 10mg/kg). Blood samples were collected prior to (baseline) and 2, 3, 4, 8, 12 and 24h subsequent to the treatments. Serum leptin and ghrelin were measured by radioimmunoassay. The mean baseline serum leptin and ghrelin were 2.5+/-0.1 ng/mL (n=40) and 35.0+/-2.1 pg/mL (n=40), respectively. In the control dogs, serum leptin, but not ghrelin levels showed a significant fluctuation during the 24h observation period. Serum leptin increased significantly (p<0.05-0.01) between 2 and 12h after 1mg/kg of methylprednisolone. Serum leptin levels showed biphasic response to 5mg/kg of methylprednisolone: its level decreased to 1.9+/-0.1 ng/mL (p<0.01) at 2h and increased at 12h (2.6+/-0.1 ng/mL) (p<0.01). In response to 10mg/kg of methylprednisolone, serum leptin levels decreased significantly (p<0.01) for 24h. Serum ghrelin levels decreased to 19+/-5 pg/mL at 2-3h (p<0.01) or increased to 87+/-18 pg/mL at 3-8h (p<0.05-0.01) after 1mg/kg of methylprednisolone or 10mg/kg of methylprednisolone, respectively. Serum ghrelin levels did not change at any time point during 24h observation period after 5mg/kg of methylprednisolone. There was a significant (p<0.001) inverse correlation (r=-0.635) between serum leptin and ghrelin levels. In conclusion, we found that methylprednisolone increases or decreases serum leptin and ghrelin levels depending upon its dose and there is a negative correlation between serum leptin and ghrelin levels after methylprednisolone administration.

Intravenous administration of choline or cdp-choline improves platelet count and platelet closure times in endotoxin-treated dogs

This study was performed to assess the effects of intravenous choline chloride and cytidine-5'-diphosphate choline (CDP-choline) treatments on circulating platelet, white blood cell, and red blood cell counts and platelet functions in response to endotoxin. Saline (0.2 mL/kg), choline chloride (20 mg/kg), or CDP-choline (70 mg/kg) were given intravenously three times at 4-h intervals, and endotoxemia was induced by endotoxin (E. coli 055:B5, 20 microg/kg) infusion, 5 min after the first treatment. Blood samples were collected before and at multiple time points after the challenge, for a panel of hematologic parameters and platelet closure times measured by PFA-100. In saline-treated dogs, circulating platelet counts decreased by 85% (P < 0.001) at 0.5 h and remained low by 36%-80% (P < 0.5-0.001) 1-12 h after endotoxin. Circulating WBC counts decreased by 80%-90% (P < 0.001) at 0.5-2 h, and increased (P < 0.001) by 190% 12 h after the endotoxin. In response to endotoxin, RBCs increased by 10%-13% (P < 0.05) at 1-12 h. Endotoxin-induced decline in circulating platelets was attenuated at 0.5 h (P < 0.05-0.01) and reversed at 1-12 h (P < 0.05-0.001) by choline. Platelet closure times were shortened from 81 +/- 10 s and 135 +/- 10 s to 29 +/- 5 s (P < 0.001) and 60 +/- 3 s (P < 0.001) at 0.5 h, and prolonged (P < 0.001) at 1-8 h after endotoxin induction. Endotoxin-induced shortening in platelet closure times was attenuated (P < 0.05) and blocked (P < 0.01) by choline and CDP-choline, respectively. These results showed that choline and CDP-choline treatments improved circulating platelet counts and platelet function during endotoxemia in dogs.