RESUMO
Silver nanoparticles (AgNPs) have become widespread in the environment with increasing industrial applications. But the studies about their potential health risks are far from enough, especially in neurotoxic effects. This study aimed to investigate the neurotoxic effects of longer-term exposure (prolonged exposure for 48 h and chronic exposure for 6 days) of 20nm AgNPs with/without polyvinylpyrrolidone (PVP) coating at low concentrations (0.01-10 mg·L-1 ) to Caenorhabditis elegans. The results suggested that exposure to AgNPs induced damage to nematode survival, with the longest and relative average life span reduced. Exposure to AgNPs caused neurotoxicity on locomotion behaviors (head thrashes, body bends, pharyngeal pumping frequency, and defecation interval) and sensory perception behaviors (chemotaxis assay and thermotaxis assay), as well as impaired dopaminergic, GABAergic, and cholinergic neurons, except for glutamatergic, based on the alters fluorescence intensity, in a dose- and time-dependent manner. Further investigations suggested that the low-dose AgNPs (0.01-0.1 mg·L-1 ) exposure raises receptors of GABAergic and dopamine in C. elegans at the genetic level, whereas opposite results were observed at higher doses (1-10 mg·L-1 ), which implied that AgNPs could cause neurotoxicity by impairing neurotransmitter delivery. The PVP-AgNPs could cause a higher fatality rate and neurotoxicity at the same dose. Notably, AgNPs did not cause any deleterious effect on nematodes at the lowest dose of 0.01 mg·L-1 . In general, these results suggested that AgNPs possess the neurotoxic potential in C. elegans and provided useful information to understand the neurotoxicity of AgNPs, which would offer an inspiring perspective on the safe application.
Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Neurônios/efeitos dos fármacos , Povidona/toxicidade , Prata/toxicidade , Animais , Caenorhabditis elegans/fisiologia , Neurônios/fisiologia , Síndromes Neurotóxicas/etiologia , Síndromes Neurotóxicas/fisiopatologia , Excipientes Farmacêuticos/toxicidade , Substitutos do Plasma/toxicidadeRESUMO
Objective: Epidural blood patch is the procedure of choice to relieve postdural puncture headache. Hydroxyethyl-starch (HES) has been proposed as a patch in some circumstances such as in the case of hematological disease due to the theoretical risk of neoplastic seeding to the central nervous system. Acute neurological HES toxicity has been excluded by a previous animal study, but the long-term neurological toxicity has not been evaluated. Methods: Rats were randomly assigned to one of three groups: no intrathecal injection, 20 µL of intrathecal saline, or a 20-µL intrathecal HES (6% hydroxyethyl starch 130/0.4) administered via a cervical puncture. Clinical daily rat activity was measured before and after dural puncture by actinometry. The rats were killed at day 28, and the spinal cord was surgically removed and stained with hematoxylin-phloxine-saffron for gross and microscopic examination. Results: Eleven rats underwent dural puncture without injection, 11 were injected with normal saline, and 12 received intrathecal HES. No clinical or actimetric changes (total distance traveled, number of direction changes, and number of rearings) were observed up to one month after injection. Nonspecific histopathological changes were equally observed in all groups. Conclusions: The results of the current study indicate that intrathecal injection of HES in rats does not induce any clinical or histopathological evidence of long-term neuronal toxicity. Further safety studies in animals are warranted before HES might be considered a safe alternative to the classic epidural blood patch.
Assuntos
Derivados de Hidroxietil Amido/toxicidade , Atividade Motora/efeitos dos fármacos , Substitutos do Plasma/toxicidade , Cefaleia Pós-Punção Dural/terapia , Medula Espinal/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Placa de Sangue Epidural , Injeções Espinhais , Masculino , Ratos , Medula Espinal/patologiaRESUMO
Sanguinate, a polyethylene glycol-conjugated carboxyhemoglobin, was investigated for cerebral vasoactivity in healthy male Sprague-Dawley rats (Study 1) and for its ability to increase brain tissue oxygen pressure (PbtO2) after controlled cortical impact (CCI) - traumatic brain injury (TBI) (Study 2). In both studies ketamine-acepromazine anesthetized rats were ventilated with 40% O2. In Study 1, a cranial window was used to measure the diameters of medium - (50-100µm) and small-sized (<50µm) pial arterioles before and after four serial infusions of Sanguinate (8mL/kg/h, cumulative 16mL/kg IV), volume-matched Hextend, or normal saline. In Study 2, PbtO2 was measured using a phosphorescence quenching method before TBI, 15min after TBI (T15) and then every 10min thereafter for 155min. At T15, rats received either 8mL/kg IV Sanguinate (40mL/kg/h) or no treatment (saline, 4mL/kg/h). Results showed: 1) in healthy rats, percentage changes in pial arteriole diameter were the same among the groups, 2) in TBI rats, PbtO2 decreased from 36.5±3.9mmHg to 19.8±3.0mmHg at T15 in both groups after TBI and did not recover in either group for the rest of the study, and 3) MAP increased 16±4mmHg and 36±5mmHg after Sanguinate in healthy and TBI rats, respectively, while MAP was unchanged in control groups. In conclusion, Sanguinate did not cause vasoconstriction in the cerebral pial arterioles of healthy rats but it also did not acutely increase PbtO2 when administered after TBI. Sanguinate was associated with an increase in MAP in both studies.
Assuntos
Arteríolas/efeitos dos fármacos , Lesões Encefálicas Traumáticas/tratamento farmacológico , Carboxihemoglobina/farmacologia , Circulação Cerebrovascular/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Oxigênio/metabolismo , Pia-Máter/irrigação sanguínea , Substitutos do Plasma/farmacologia , Polietilenoglicóis/farmacologia , Animais , Pressão Arterial/efeitos dos fármacos , Arteríolas/metabolismo , Arteríolas/fisiopatologia , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/fisiopatologia , Carboxihemoglobina/análogos & derivados , Carboxihemoglobina/toxicidade , Modelos Animais de Doenças , Derivados de Hidroxietil Amido/farmacologia , Masculino , Microcirculação/efeitos dos fármacos , Substitutos do Plasma/toxicidade , Polietilenoglicóis/toxicidade , Ratos Sprague-Dawley , Fatores de Tempo , Vasoconstrição/efeitos dos fármacosRESUMO
Epidural blood patch is the gold standard treatment for post-dural puncture headache, although hydroxyethyl starch may be a useful alternative to blood if the latter is contraindicated. The aim of this experimental study was to assess whether hydroxyethyl starch given via an indwelling intrathecal catheter resulted in clinical or histopathological changes suggestive of neurotoxicity. The study was conducted in rats that were randomly allocated to receive three 10-µl injections on consecutive days of either saline or hydroxyethyl starch administered via the intrathecal catheter. Eight rats were given injections of saline 0.9% and 11 were given 6% hydroxyethyl starch 130/0.4 derived from thin boiling waxy corn starch in 0.9% sodium chloride (Voluven). Daily clinical evaluation, activity measured by actimetry and neuropathological analysis of the spinal cord were subsequently performed to assess for signs of neurotoxicity. No clinical or actimetric changes were observed in either group following intrathecal saline or hydroxyethyl starch administration. Histopathological examination showed non-specific changes with no differences between the two groups. This experimental study in the rat suggests that repeated intrathecal injection of hydroxyethyl starch is not associated with neurotoxicity.
Assuntos
Derivados de Hidroxietil Amido/toxicidade , Síndromes Neurotóxicas/etiologia , Substitutos do Plasma/toxicidade , Animais , Modelos Animais de Doenças , Injeções Espinhais , Masculino , Ratos , Ratos Sprague-Dawley , Cloreto de Sódio/administração & dosagemRESUMO
Hemoglobin-based oxygen carriers (HBOCs) may generate oxidative stress, vasoconstriction and inflammation. To reduce these undesirable vasoactive properties, we increased hemoglobin (Hb) molecular size by genetic engineering with octameric Hb, recombinant (r) HbßG83C. We investigate the potential side effects of rHbßG83C on endothelial cells. The rHbßG83C has no impact on cell viability, and induces a huge repression of endothelial nitric oxide synthase gene transcription, a marker of vasomotion. No induction of Intermolecular-Adhesion Molecule 1 and E-selectin (inflammatory markers) transcription was seen. In the presence of rHbßG83C, the transcription of heme oxygenase-1 (oxidative stress marker) is weakly increased compared to the two other HBOCs (references) or Voluven (control). This genetically engineered octameric Hb, based on a human Hb ßG83C mutant, leads to little impact at the level of endothelial cell inflammatory response and thus appears as an interesting molecule for HBOC development.
Assuntos
Substitutos Sanguíneos/farmacologia , Hemoglobinas/farmacologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Biomarcadores , Substitutos Sanguíneos/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Dextranos/farmacologia , Dextranos/toxicidade , Regulação para Baixo/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Selectina E/biossíntese , Selectina E/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Heme Oxigenase-1/biossíntese , Heme Oxigenase-1/genética , Hemoglobinas/análise , Hemoglobinas/química , Hemoglobinas/toxicidade , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Derivados de Hidroxietil Amido/farmacologia , Derivados de Hidroxietil Amido/toxicidade , Inflamação/induzido quimicamente , Molécula 1 de Adesão Intercelular/biossíntese , Molécula 1 de Adesão Intercelular/genética , Metemoglobina/análise , Modelos Moleculares , Óxido Nítrico Sintase Tipo III/biossíntese , Óxido Nítrico Sintase Tipo III/genética , Estresse Oxidativo/efeitos dos fármacos , Substitutos do Plasma/farmacologia , Substitutos do Plasma/toxicidade , Conformação Proteica , Reação em Cadeia da Polimerase em Tempo Real , Vasoconstrição/efeitos dos fármacosRESUMO
BACKGROUND: Acute normovolemic hemodilution (ANH) is currently performed during thoracoabdominal aortic surgery. However, the effects of ANH on spinal cord ischemic injury are currently unknown. Because hemodilution below a certain level of hematocrit (Hct) aggravates the neurological damage after cerebral ischemia, we hypothesized that ANH may increase neurological damage after spinal cord ischemia. The aim of these experiments was to determine the effects of ANH on spinal cord ischemic injury. METHODS: Thirty male Sprague-Dawley rats were randomly assigned to 1 of the following 3 groups: no hemodilution (group C), target Hct level of 30% (group HD30), and target Hct level of 25% (group HD25). ANH was performed upon withdrawal of blood and simultaneous replacement with the same volume with hydroxyethyl starch. Spinal cord ischemia and reperfusion were induced by using a balloon-tipped catheter placed in the descending thoracic aorta, and changes in mean arterial blood pressure were recorded. Neurological function of the hindlimbs was evaluated for 7 days and recorded using a motor deficit score (MDS) (0 = normal; 5 = complete paraplegia). The number of motor neurons within the spinal cord was counted after final MDS evaluation. RESULTS: Group HD25 developed hypotension during the latter part of the ANH procedure. Group C and group HD30 experienced 3 minutes of reperfusion hypotension, whereas 6 minutes of hypotension was observed in group HD25. Two rats in group HD25 died during the experimental period. Seven days after reperfusion, the MDS of group C, group HD30, and group HD25 was 1.0 (0.5-2.0), 1.0 (0.5-2.0), and 4.0 (2.8-4.2) (median [95% confidence interval]), respectively. Group HD25 showed significantly higher MDS compared with group C (corrected P = 0.0018; 95% CI for median difference = 1.0-3.5). Motor neuron numbers in the anterior horns of group C, group HD30, and group HD25 were 26.5 (25.0-27.5), 23.5 (22.0-26.5), and 12.5 (8.4-16.6) (median [95% CI]), respectively. Motor neuron numbers of group HD25 were significantly lower than those of group C (corrected P < 0.0001; 95% CI for median difference = 9.0-18.0). CONCLUSION: The results of the present study indicate that intraoperative ANH to an Hct of 25%, combined with coincident hypotension, caused a delayed recovery of baseline mean arterial blood pressure during the reperfusion period and aggravated neurological outcome after spinal cord ischemia.
Assuntos
Volume Sanguíneo , Hemodiluição/efeitos adversos , Derivados de Hidroxietil Amido/toxicidade , Atividade Motora , Neurônios Motores/patologia , Substitutos do Plasma/toxicidade , Isquemia do Cordão Espinal/etiologia , Animais , Pressão Sanguínea , Cateterismo , Modelos Animais de Doenças , Hematócrito , Hipotensão/etiologia , Hipotensão/fisiopatologia , Masculino , Ratos , Ratos Sprague-Dawley , Isquemia do Cordão Espinal/sangue , Isquemia do Cordão Espinal/patologia , Isquemia do Cordão Espinal/fisiopatologia , Fatores de TempoRESUMO
Hydroxyethylstarch (HES) 200/0.5 is associated with renal failure. Several studies have suggested that renal function is affected but the subsequent arguments leave the clinician in no man's land. A recent study in Critical Care by Simon and colleagues using a two hit animal model of shock demonstrates that the use of a higher molecular weight starch, HES 200/0.5, is associated with impaired renal function when compared with ringers acetate, gelatin or a lower molecular weight starch, HES 130/0.42. The authors conclude that both the lower molecular weight starch and the ringers acetate 'preserve renal function and attenuate tubular damage better than 10% hydroxyethylstarch 200/0.5 in saline'. Added to the previous evidence, the renal effects of HES200/0.5 are probably real. Many clinicians have already moved to the lower molecular weight starches on the basis of doubt rather than certainty, but this study tips the balance. The cause remains elusive and the lack of a mechanism should be seen as a problem.
Assuntos
Coloides/toxicidade , Modelos Animais de Doenças , Rim/efeitos dos fármacos , Substitutos do Plasma/toxicidade , Choque Hemorrágico/tratamento farmacológico , Choque Séptico/tratamento farmacológico , Animais , FemininoRESUMO
INTRODUCTION: One of the therapeutic essentials in severe sepsis and septic shock is an adequate fluid replacement to restore and maintain circulating plasma volume, improve organ perfusion and nutritive microcirculatory flow. The type of solution to be used as a fluid replacement remains under discussion. The aim of the study was to evaluate the effects of clinically used fluid replacement solutions on renal function and inflammatory response. METHODS: A total of 23 anesthetized and ventilated female German Landrace pigs were investigated over 19 hours using a two-hit model that combined hemorrhagic and septic shock. The septic shock was induced using an Escherichia coli laden clot placed into the abdominal cavity. Infusions of 6% hydroxyethylstarch 130/0.42 in acetate (6% HES 130), 4% gelatin in acetate (4% gelatin) and 10% hydroxyethylstarch 200/0.5 in saline (10% HES200) compared to Ringer's acetate (RAc) were used for fluid replacement to maintain a central venous pressure of 12 mmHg. Ringer's acetate was also used in the sham-treated group (SHAM). RESULTS: At study end the cardiac output (10% HES200 143±48 ml/kgBW; 6% HES130 171±47 ml/kgBW; RAc 137±32 ml/kgBW; 4% gelatin 160±42 ml/kgBW), as well as mean arterial pressure did not differ between groups. N-acetyl-beta-D-glucosamidase was significantly higher in the hydroxyethylstarch 200 (157±115 U/g creatinine; P<0.05) group compared to hydroxyethylstarch 130 (24±9 U/g creatinine), Ringer's acetate (2±3 U/g creatinine) and SHAM (21±15 U/g creatinine) at the study's end. Creatinine significantly increased by 87±84 percent of baseline in the 10% HES200 group compared to RAc and 6% HES130. We demonstrated in the histology of the kidneys a significant increase in osmotic-nephrosis like lesions for 4% gelatin compared to RAc, 6% HES130 and SHAM. Urine output was lowest in the 10% HES200 and 4% gelatin group, however not significantly.Interleukin(IL)-6 levels were significantly elevated in the 10% HES200 group (3,845±1,472 pg/ml) two hours after sepsis induction compared to all other groups (6% HES130 1,492±604 pg/ml; RAc 874±363 pg/ml; 4% gelatin 1,623±1,242 pg/ml). CONCLUSIONS: Despite similar maintenance of macrocirculation 6% hydroxyethylstarch 130/0.42 and Ringer's acetate significantly preserve renal function and attenuate tubular damage better than 10% hydroxyethylstarch 200/0.5 in saline.
Assuntos
Coloides/toxicidade , Modelos Animais de Doenças , Rim/efeitos dos fármacos , Substitutos do Plasma/toxicidade , Choque Hemorrágico/tratamento farmacológico , Choque Séptico/tratamento farmacológico , Animais , Coloides/uso terapêutico , Feminino , Hidratação/efeitos adversos , Derivados de Hidroxietil Amido/análogos & derivados , Derivados de Hidroxietil Amido/uso terapêutico , Derivados de Hidroxietil Amido/toxicidade , Rim/patologia , Rim/fisiologia , Substitutos do Plasma/uso terapêutico , Distribuição Aleatória , Choque Hemorrágico/patologia , Choque Séptico/patologia , SuínosRESUMO
Renal failure is a common complication of critically ill patients. Colloids such as hydroxyethyl starch (HES), gelatin, or albumin are regularly used for intravascular volume resuscitation, but there are increasing reports about the nephrotoxic side effects of synthetic colloids in septic patients. Therefore, we investigated the influence of colloids (HES130/0.4 (Voluven®), gelatin (Gelafundin®), human albumin, and the crystalloid Sterofundin® ISO on cell viability of human proximal tubular (HK-2) cells. HK-2 cells were incubated with colloids (0.1%-4%) and with equivalent volumes of the crystalloid solution Sterofundin ISO. After 21 hours, cell viability of HK-2 cells was measured by EZ4U assay (dye XTT). Application of HES130/0.4 decreased cell viability significantly in a concentration-dependent manner (86.80% ± 10.79% by 0.5% HES down to 24.02% ± 4.27% by 4% HES). Human albumin (>1.25%) as well as gelatin (>1%) also showed deleterious effects on HK-2 cells. Interestingly, in lower concentrations, human albumin and the crystalloid solution Sterofundin ISO were cytoprotective in comparison with the NaCl control. In conclusion, synthetic and natural colloids showed a harmful impact on HK-2 cells in higher concentrations without any prior proinflammatory stimulus. HES130/0.4 exhibited the most distinctive harmful impact, whereas the application of crystalloid Sterofundin ISO revealed cytoprotective effects.
Assuntos
Albuminas/toxicidade , Gelatina/toxicidade , Derivados de Hidroxietil Amido/toxicidade , Soluções Isotônicas/toxicidade , Túbulos Renais Proximais/efeitos dos fármacos , Substitutos do Plasma/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Coloides , Soluções Cristaloides , Citoproteção , Relação Dose-Resposta a Droga , Humanos , Túbulos Renais Proximais/patologia , Compostos Orgânicos/toxicidade , Fatores de TempoRESUMO
OBJECTIVE: The purpose of this review is to draw up a statement on current knowledge available on the more recent hydroxyethyl starch (HES). DATA SOURCES: References were obtained from computerized bibliographic research (Medline), recent review articles, the library of the service and personal files. STUDY SELECTION: All categories of articles on this topic have been selected. DATA EXTRACTION: Articles have been analysed for biophysics, pharmacology, toxicity, side effects, clinical effects and using prospect of HES. DATA SYNTHESIS: The first HES was made available in the United States in 1970. The development of a new generation of HES restarted the discussion on clinical interest and the limits in the use of these macromolecules. This interest is also strengthened today by the recent data attached to plasma substitution in intensive care or perioperative resuscitation. The interest for crystalloids and colloids is still widely debated, and among the latter, the relative interest of the HES last generation compared to older ones. Recent HES development is in line with a decrease molecular weight, change rate molar substitution and to amend the glucose to hydroxyethyl report. The ultimate goal is to reduce the side effects of these molecules preventing their use. Side effects are dominated by haemostasis and renal dysfunction. The latest developments are the so-called HES "balanced" solutions.
Assuntos
Derivados de Hidroxietil Amido/uso terapêutico , Substitutos do Plasma/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , Cuidados Críticos , Humanos , Derivados de Hidroxietil Amido/efeitos adversos , Derivados de Hidroxietil Amido/química , Derivados de Hidroxietil Amido/farmacologia , Derivados de Hidroxietil Amido/toxicidade , Nefropatias/induzido quimicamente , Peso Molecular , Soluções Farmacêuticas , Substitutos do Plasma/efeitos adversos , Substitutos do Plasma/farmacologia , Substitutos do Plasma/toxicidade , Volume PlasmáticoRESUMO
BACKGROUND: Conflicting data exist on the renal effects of hydroxyethyl starch (HES) preparations. The current study evaluates the effects of saline-based 6% HES 130/0.4, 10% HES 200/0.5, and a balanced isotonic crystalloid on renal function and microscopic changes in ovine endotoxemic shock. METHODS: Thirty sheep were subjected to endotoxin infusion (Salmonella typhosa) at incremental doses until mean arterial pressure was less than 65 mmHg. Animals were randomized to receive fluid resuscitation with saline-based 6% HES 130/0.4, 10% HES 200/0.5, or a balanced isotonic crystalloid (n = 10 each). Animals surviving the 12-h intervention period were anesthetized and killed. Kidney samples were taken for microscopic analyses. RESULTS: Endotoxemia was associated with hemoconcentration, protein extravasation, and arterial hypotension. Fluid resuscitation established a hypotensive-hyperdynamic circulation with increased cardiac index and oxygen delivery and decreased afterload. Diuresis was lowest in animals treated with 10% HES 200/0.5. In addition, plasma creatinine and urea concentrations increased in sheep treated with 10% HES 200/0.5 (1.2 +/- 0.1 and 19 +/- 2 mg/dl) when compared with the other two groups (0.9 +/- 0.1 and 15 +/- 1 mg/dl, 6% HES 130/0.4; 0.9 +/- 0.1 and 15 +/- 1 mg/dl, crystalloids; each P < 0.05). Electron microscopic tubular injury score was highest in sheep treated with 10% HES 200/0.5 (P < 0.001 vs. 6% HES 130/0.4). CONCLUSIONS: In ovine endotoxemic shock, saline-based 10% HES 200/0.5 was linked to impaired renal function and more pronounced tubular epithelial injury when compared with 6% HES 130/0.4 and balanced crystalloids.
Assuntos
Endotoxemia/patologia , Derivados de Hidroxietil Amido/toxicidade , Nefropatias/induzido quimicamente , Nefropatias/patologia , Rim/patologia , Substitutos do Plasma/toxicidade , Choque Séptico/patologia , Animais , Peso Corporal , Creatinina/sangue , Diurese , Endotoxinas/toxicidade , Feminino , Hemodinâmica/fisiologia , Rim/ultraestrutura , Testes de Função Renal , Túbulos Renais/patologia , Lipopolissacarídeos/toxicidade , Microscopia Eletrônica , Microscopia Eletrônica de Transmissão , Pressão Osmótica , Consumo de Oxigênio/efeitos dos fármacos , Proteínas/metabolismo , Circulação Renal/efeitos dos fármacos , Circulação Renal/fisiologia , Ovinos , Ureia/sangueRESUMO
BACKGROUND: Colloid plasma expanders are used to maintain blood pressure and ensure tissue perfusion during hypovolemia, e.g., caused by traumatic bleeding. Although colloids stabilize the cardiovascular system, they can also potentially cause coagulopathy. Consequently, bleeding tendency may increase, as well as the associated risk of morbidity and mortality. Thus, there is a need for hemostatic treatment options for these patients. rFVIIa (NovoSeven, Novo Nordisk A/S, Bagsvaerd, Denmark) is a hemostatic agent that effectively controls bleedings in patients with inhibitor-complicated hemophilia. rFVIIa works by enhancing thrombin generation on the activated platelet surface at the site of injury, leading to the formation of a stable fibrin clot. NN1731 is an rFVIIa analog with increased hemostatic potential and is currently under clinical development. METHODS: In this study, the effect of rFVIIa and NN1731 on cuticle bleeding in rabbits 50% hemodiluted with hydroxyethyl starch (molecular weight â¼ 200,000) was tested. Cuticle bleeding was induced after a two-stage hemodilution procedure. After 5 minutes, the animals were treated with rFVIIa (2, 5, or 10 mg/kg), NN1731 (1 or 2 mg/kg), or vehicle, followed by 30 minutes of observation. RESULTS: Hemodilution caused a significant increase in bleeding time and blood loss. rFVIIa dose-dependently reduced bleeding time and blood loss, reaching statistical significance at 10 mg/kg. However, 2 mg/kg NN1731 reduced bleeding time and blood loss significantly and to a similar extent as 10 mg/kg rFVIIa. This increased hemostatic potential of NN1731 compared with rFVIIa and was confirmed by findings using thromboelastography on ex vivo hemodiluted whole blood. CONCLUSION: In summary, rFVIIa and NN1731 significantly and dose-dependently reduced bleeding in extensively hemodiluted rabbits.
Assuntos
Fator VII/administração & dosagem , Fator VIIa/administração & dosagem , Hemorragia/tratamento farmacológico , Animais , Tempo de Sangramento , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Hemodiluição/efeitos adversos , Hemodiluição/métodos , Hemorragia/sangue , Hemorragia/induzido quimicamente , Derivados de Hidroxietil Amido/toxicidade , Substitutos do Plasma/toxicidade , Coelhos , Proteínas Recombinantes/administração & dosagem , Espectrofotometria , Tromboelastografia , Resultado do TratamentoRESUMO
Colloid infusions can cause metabolic acidosis. Mechanisms and relative severity with different colloids are incompletely understood. We compared haemodilution acid-base effects of 4% albumin, 3.5% polygeline, 4% succinylated gelatin (all weak acid colloids, strong ion difference 12 mEq/l, 17.6 mEq/l and 34 mEq/l respectively), 6% hetastarch (non-weak acid colloid, strong ion difference zero) and 0.9% saline (crystalloid, strong ion difference zero). Gelatin weak acid properties were tracked via the strong ion gap. Four-step ex vivo dilutions of pre-oxygenated human venous blood were performed to a final [Hb] near 50% baseline. With each fluid, base excess fell to approximately -13 mEq/l. Base excess/[Hb] relationships across dilution were linear and direct (R2 > or = 0.96), slopes and intercepts closely resembling saline. Baseline strong ion gap was -0.3 (2.1) mEq/l. Post-dilution increases occurred in three groups: small with saline, hetastarch and albumin (to 3.5 (02) mEq/l, 4.3 (0.3) mEq/l, 3.3 (1.4) mEq/l respectively), intermediate with polygeline (to 12.2 (0.9) mEq/l) and greatest with succinylated gelatin (to 20.8 (1.4) mEq/l). We conclude that, despite colloid weak acid activity ranging from zero (hydroxyethyl starch) to greater than that of albumin with both gelatin preparations, ex vivo dilution causes a metabolic acidosis of identical severity to saline in each case. This uniformity reflects modifications to the albumin and gelatin saline vehicles, in part aimed at pH correction. By proportionally increasing the strong ion difference, these modifications counter deviations from pure saline effects caused by colloid weak acid activity. Extrapolation in vivo requires further investigation.
Assuntos
Equilíbrio Ácido-Base/efeitos dos fármacos , Acidose/induzido quimicamente , Hemodiluição/métodos , Albuminas/toxicidade , Coloides/química , Coloides/toxicidade , Gelatina/toxicidade , Humanos , Concentração de Íons de Hidrogênio , Derivados de Hidroxietil Amido/toxicidade , Técnicas In Vitro , Substitutos do Plasma/química , Substitutos do Plasma/toxicidade , Poligelina/toxicidade , Índice de Gravidade de Doença , Cloreto de Sódio/toxicidade , Succinatos/toxicidadeRESUMO
Zinc (Zn) and its binding protein metallothionein (MT) have been proposed to suppress the disease activity in ulcerative colitis. To determine the role of Zn and MT in the dextran sulfate sodium (DSS)-induced model of colitis in mice, a DSS dose-response study was conducted in male C57BL/6 wild-type (MT+/+) and MT-null (MT-/-) mice by supplementing 2%, 3%, and 4% DSS in the drinking water for 6 days. In the intervention study, colitis was induced with 2% DSS, Zn (24 mg/ml as ZnO) was gavaged (0.1 ml) daily, concurrent with DSS administration, and the disease activity index (DAI) was scored daily. Histology, MT levels, and myeloperoxidase (MPO) activity were determined. DAI was increased (P<0.05) by 16% and 21% with 3% and 4% concentrations of DSS, respectively, compared to 2%, evident after 5 days of DSS administration. MPO activity was increased in MT+/+ compared to MT-/- mice and those receiving DSS. Zn administration had a 50% (P<0.05) lower DAI compared to DSS alone. Zn partially prevented the distal colon of MT+/+ by 47% from DSS-induced damage compared to MT-/- mice. MT did not prevent DSS-induced colitis and Zn was partially effective in amelioration of DSS-induced colitis.
Assuntos
Colite Ulcerativa/tratamento farmacológico , Metalotioneína/uso terapêutico , Oligoelementos/uso terapêutico , Zinco/uso terapêutico , Animais , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/metabolismo , Colo/efeitos dos fármacos , Colo/metabolismo , Colo/patologia , Sulfato de Dextrana/administração & dosagem , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Seguimentos , Masculino , Metalotioneína/farmacocinética , Camundongos , Camundongos Endogâmicos C57BL , Peroxidase/metabolismo , Substitutos do Plasma/administração & dosagem , Substitutos do Plasma/toxicidade , Índice de Gravidade de Doença , Espectrofotometria , Oligoelementos/farmacocinética , Resultado do Tratamento , Zinco/farmacocinéticaRESUMO
Peroxisome proliferator-activated receptors (PPARs) beta/delta and gamma have overlapping roles in the negative regulation of inflammatory response genes. Ligand activation of PPARgamma protects against experimental colitis in mice. PPARbeta/delta can negatively regulate inflammation and is highly expressed in the epithelial cells of the colon, therefore PPARbeta/delta may also have a role in experimental colitis. In these studies, colitis was induced by dextran sodium sulfate (DSS) treatment in wild-type and PPARbeta/delta-null mice, with and without the PPARbeta/delta specific ligand GW0742. PPARbeta/delta-null mice exhibited increased sensitivity to DSS-induced colitis, as shown by marked differences in body weight loss, colon length, colonic morphology, myeloperoxidase activity and increased expression of mRNAs encoding the inflammatory markers interferon gamma, tumor necrosis factor-alpha, and interleukin-6 compared to similarly treated wild-type mice. Interestingly, these differences were not affected by ligand activation of PPARbeta/delta in either genotype. These studies demonstrate that PPARbeta/delta expression in the colonic epithelium inhibits inflammation and protects against DSS-induced colitis through a ligand-independent mechanism.
Assuntos
Colite/prevenção & controle , PPAR delta/uso terapêutico , PPAR beta/uso terapêutico , Animais , Colite/induzido quimicamente , Colite/metabolismo , Colo/metabolismo , Colo/patologia , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Progressão da Doença , Enterócitos/metabolismo , Enterócitos/patologia , Feminino , Expressão Gênica/efeitos dos fármacos , Interferon gama/genética , Interferon gama/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Peroxidase/metabolismo , Substitutos do Plasma/toxicidade , Reação em Cadeia da Polimerase , RNA Mensageiro/genética , Índice de Gravidade de Doença , Tiazóis , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Recombinant fibroblast growth factors (FGFs) maintain the integrity of the gut epithelium and reduce mucosal injury in experimental inflammatory bowel disease (IBD). Chemically synthesized FGF mimetics could potentially extend the utility of FGFs by tailoring them for optimal bioactivity and oral administration, for example. Here, F2A4-K-NS (Fibratide), a synthetic FGF mimetic peptide, alleviated dextran sulfate sodium (DSS)-induced ulcerative colitis in mice when delivered systemically and, to a lesser extent, orally. Intraperitoneal injection of Fibratide (1 or 5 mg/kg/day) ameliorated DSS-induced ulcerative colitis, resulting in reduced weight loss, decreased colon wall thickening, and increased colon length. Fibratide also improved epithelial integrity by reducing histological-detectable crypt damage and inflammation. Orally administered Fibratide (1 mg/kg/day) was also effective in ameliorating symptoms with effects generally similar to those of intraperitoneal injection. In vitro studies were conducted to help clarify how Fibratide might act in vivo. Fibratide exhibited a modest enhancement of epithelial cell proliferation. On the other hand, Fibratide doubled the rate of epithelial cells migration and restitution in a cell culture model of wound repair. Collectively, the results indicate that Fibratide reduced the severity of experimental ulcerative colitis and may be potentially useful in the treatment of IBD.
Assuntos
Colite Ulcerativa/tratamento farmacológico , Fator 2 de Crescimento de Fibroblastos/administração & dosagem , Administração Oral , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/patologia , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Fator 2 de Crescimento de Fibroblastos/síntese química , Injeções Intraperitoneais , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Camundongos , Camundongos Endogâmicos C57BL , Substitutos do Plasma/toxicidade , Proteínas Recombinantes/síntese química , Resultado do TratamentoRESUMO
BACKGROUND & AIMS: Toll-like receptors (TLRs) represent a class of transmembrane pattern recognition receptors essential for microbial recognition and control of innate immune responses. Commensal bacteria play an important role in maintaining tolerance and active stability of the intestinal epithelial barrier by suppressing intestinal inflammation, yet the mechanisms of action are unknown. The aim of this study was to determine the functional relevance of TLR2 to control tight junction (TJ)-associated intestinal epithelial barrier integrity to balance mucosal homeostasis against inflammatory stress-induced damage. METHODS: TLR2 ligand (synthetic Pam(3)Cys-SK4 [PCSK])-induced activation of signaling cascades and TJ-associated distribution was assessed by using Western blotting and confocal microscopy combined with functional transfection and inhibitor studies in model intestinal epithelial cell (IEC) lines (IEC-6, Caco-2) or primary IEC cultured short-term ex vivo. DSS colitis was induced by standard protocol in wild-type, TLR2-/-, and MyD88-/- mice. Spontaneous apoptosis was assessed by terminal deoxinucleotidyl-transferase-mediated dUTP-biotin nick end-labeling. RESULTS: Data from in vitro and ex vivo models of intestinal epithelial cells revealed that TLR2 stimulation effectively preserves TJ-associated barrier assembly against stress-induced damage through promotion of PI3K/Akt-mediated cell survival via MyD88. Furthermore, in vivo studies underscored that TLR2-mediated TJ regulation critically determines susceptibility to intestinal injury and inflammation. Inflammatory stress in mice deficient of TLR2 or MyD88 induced early TJ-associated disruption interrelated with anti-apoptotic failure of the intestinal epithelial barrier. Oral treatment of colitis with the TLR2 ligand PCSK significantly suppressed mucosal inflammation and apoptosis by efficiently restoring TJ-associated integrity of the intestinal epithelium in vivo. CONCLUSION: TLR2 may provide a target to pharmacologically modulate mucosal injury and intestinal inflammation.
Assuntos
Colite/metabolismo , Epitélio/metabolismo , Mucosa Intestinal/metabolismo , Receptor 2 Toll-Like/metabolismo , Animais , Apoptose , Western Blotting , Linhagem Celular , Sobrevivência Celular , Colite/induzido quimicamente , Colite/patologia , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Epitélio/efeitos dos fármacos , Epitélio/patologia , Feminino , Imuno-Histoquímica , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Lipopeptídeos , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Peptídeos/farmacocinética , Permeabilidade , Substitutos do Plasma/toxicidade , Índice de Gravidade de Doença , Receptor 2 Toll-Like/agonistasRESUMO
BACKGROUND & AIMS: R-spondin 1 (Rspo1) is a novel epithelial mitogen that stimulates the growth of mucosa in both the small and large intestine. METHODS: We investigated the therapeutic potential of Rspo1 in ameliorating experimental colitis induced by dextran sulfate sodium (DSS) or trinitrobenzene sulfonic acid (TNBS) as well as nonsteroidal anti-inflammatory drug-induced colitis in interleukin (IL)-10-deficient mice. RESULTS: Therapeutic administration of recombinant Rspo1 protein reduced the loss of body weight, diarrhea, and rectal bleeding in a mouse model of acute or chronic DSS-induced colitis. Histologic evaluation revealed that Rspo1 improved mucosal integrity in both villus and/or crypt compartments in the small intestine and colon by stimulating crypt cell growth and mucosal regeneration in DSS-treated mice. Moreover, Rspo1 significantly reduced DSS-induced myeloperoxidase activity and inhibited the overproduction of proinflammatory cytokines, including tumor necrosis factor-alpha, IL-1alpha, IL-6, interferon-gamma, and granulocyte-macrophage colony-stimulating factor, in mouse intestinal tissue, indicating that Rspo1 may reduce DSS-induced inflammation by preserving the mucosal barrier function. Likewise, Rspo1 therapy also alleviated TNBS-induced interstitial inflammation and mucosal erosion in the mouse colon. Furthermore, Rspo1 substantially decreased the histopathologic severity of chronic enterocolitis by repairing crypt epithelium and simultaneously suppressing inflammatory infiltration in piroxicam-exposed IL-10(-/-) mice. Endogenous Rspo1 protein was localized to villus epithelium and crypt Paneth cells in mouse small intestine. CONCLUSIONS: Our results show that Rspo1 may be clinically useful in the therapeutic treatment of inflammatory bowel disease by stimulating crypt cell growth, accelerating mucosal regeneration, and restoring intestinal architecture.
Assuntos
Colite/tratamento farmacológico , Colo/patologia , Mitógenos/uso terapêutico , Trombospondinas/uso terapêutico , Doença Aguda , Animais , Anti-Inflamatórios não Esteroides/toxicidade , Proliferação de Células/efeitos dos fármacos , Colite/induzido quimicamente , Colite/patologia , Colo/efeitos dos fármacos , Colo/metabolismo , Citocinas/antagonistas & inibidores , Citocinas/biossíntese , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Feminino , Imuno-Histoquímica , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/metabolismo , Intestino Delgado/patologia , Camundongos , Camundongos Endogâmicos BALB C , Piroxicam/toxicidade , Substitutos do Plasma/toxicidade , Proteínas Recombinantes/uso terapêutico , Índice de Gravidade de Doença , Resultado do Tratamento , Ácido Trinitrobenzenossulfônico/toxicidadeRESUMO
We examined the effect of cyclooxygenase (COX) inhibitors on dextran sulfate sodium (DSS)-induced ulcerative colitis in rats and investigated the role of COX isozymes in the pathogenesis of this model. Experimental colitis was induced by treatment with 2.5% DSS in drinking water for 6 days. Indomethacin (a nonselective COX inhibitor), SC-560 (a selective COX-1 inhibitor), or celecoxib (a selective COX-2 inhibitor) was given PO twice daily for 6 days, during the first 3 or last 3 days of the experimental period. Daily treatment with 2.5% DSS for 6 days caused damage to the colon, with a decrease in body weight gain and colon length as well as an increase of myeloperoxidase (MPO) activity. All COX inhibitors given for 6 days significantly worsened the severity of DSS-induced colonic damage with increased MPO activity. The aggravation was also observed by SC-560 given for the first 3 days or by celecoxib given for the last 3 days. The expression of COX-2 mRNA in the colon was upregulated on day 3 during DSS treatment, with significant increase of prostaglandin E(2) PGE(2) production. The PGE(2) content on day 3 during DSS treatment was inhibited by both indomethacin and SC-560, but not by celecoxib; on day 6 it was suppressed by both indomethacin and celecoxib, but not SC-560. These results suggest that endogenous prostaglandins (PGs) afford protection against colonic ulceration, yet the COX isozyme responsible for the production of PGs differs depending on the stage of ulceration; COX-1 in the early stage and COX-2 in the late stage.
Assuntos
Colite Ulcerativa/tratamento farmacológico , Ciclo-Oxigenase 1/efeitos dos fármacos , Ciclo-Oxigenase 2/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase/uso terapêutico , Pirazóis/uso terapêutico , Sulfonamidas/uso terapêutico , Animais , Doenças Cardiovasculares , Celecoxib , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/metabolismo , Colo/efeitos dos fármacos , Colo/metabolismo , Colo/patologia , Ciclo-Oxigenase 2/genética , Sulfato de Dextrana/toxicidade , Dinoprostona/biossíntese , Modelos Animais de Doenças , Expressão Gênica/efeitos dos fármacos , Indometacina/uso terapêutico , Masculino , Peroxidase/metabolismo , Substitutos do Plasma/toxicidade , RNA Mensageiro/genética , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espectrofotometria , Resultado do TratamentoRESUMO
Curcumin is a phenolic natural product isolated from the rhizome of Curcuma longa (turmeric). We evaluated the effects of curcumin on the development of dextran sulfate sodium (DSS)-induced experimental colitis. BALB/c mice were fed a chow containing either 3.5% (wt/wt) DSS or 3.5% DSS + 2.0% (wt/wt) curcumin. The body weight loss was more apparent in DSS-treated mice than in DSS + curcumin-treated mice. The disease activity index, histological colitis score, and MPO activity were all significantly higher in DSS-treated mice than in DSS plus curcumin-treated mice. Microscopically, mucosal edema, cellular infiltration, and epithelial disruption were much more severe in DSS-treated mice than in DSS + curcumin-treated mice. In DSS + curcumin-treated mice, NF-kappaB activation was blocked in the mucosa. In conclusion, the development of DSS-induced colitis was significantly attenuated by curcumin. Being a nontoxic natural dietary product, curcumin could be useful in treatment of IBD patients.