Prophylactic use of epidermal growth factor reduces ischemia/reperfusion intestinal damage

Ischemia/reperfusion of mesenteric vessels is a useful model for acute vascular insufficiency and the early stages of multiorgan failure, conditions associated with high morbidity and mortality. Epidermal growth factor (EGF) is a potent mitogen that shows potential for use in intestinal injury. We therefore examined its influence on this model. Male Sprague-Dawley rats received human recombinant EGF (2 mg/kg i.p., n = 14) or saline (n = 16); 25 minutes before arterial clamping of the superior mesenteric artery (ischemic period) for 60 minutes followed by a final 60-minute reperfusion period. Additional rats were not operated on (controls, n = 7) or had sham operation (laparotomy only, n = 10). Ischemia/reperfusion caused macroscopic damage affecting 56%, 51 to 67% (median, interquartile range), of small intestinal length and intraluminal bleeding. Malondialdehyde levels (free radical marker) increased eightfold compared to nonoperated animals (2400, 2200 to 2700 micro mol/mg protein versus 290, 250 to 350 micro mol/mg protein, P < 0.01) and myeloperoxidase levels (marker for inflammatory infiltrate) increased 15-fold (3150, 2670 to 4180 U/g tissue versus 240, 190 to 250 U/g tissue, P < 0.01). Pretreatment with EGF reduced macroscopic injury to 11%, 0 to 15%; prevented intraluminal bleeding; and reduced malondialdehyde and myeloperoxidase levels by approximately 60% and 90% (all P < 0.01 versus non-EGF-treated). Mesenteric ischemia/reperfusion also damaged the lungs and kidneys and increased serum tumor necrosis factor-alpha levels (circulating cytokine activity marker). EGF pretreatment also reduced these changes. These studies provide preliminary evidence that EGF is a novel therapy for the early treatment or prevention of intestinal damage and multiorgan failure resulting from mesenteric hypoperfusion.     

Inhibition of rheumatoid factor production by non-steroidal anti-inflammatory drugs

The effects of NSAIDs on IgM rheumatoid factor production in vitro and on serum rheumatoid factor concentration in vivo were investigated using indomethacin (5.0μg/ml), carprofen (10μg/ml) and piroxicam (10μg/ml). IgM rheumatoid factor was isolated from lymphocytes of patients suffering from rheumatoid arthritis. NSAIDs inhibited IgM rheumatoid factor production in vitro. Furthermore, serum IgM rheumatoid factor was reduced when NSAIDs were administered in vivo. It is thought that NSAIDs effectively remove suppressor T-cells from the tonic inhibitory action of PGE₂. This previously unrecognized action of NSAIDs may be a factor in their efficacy in rheumatoid arthritis.     

Heparin-binding epidermal growth factor cleavage mediates zinc-induced epidermal growth factor receptor phosphorylation

We have previously shown that exposure to zinc ions can activate epidermal growth factor (EGF) receptor (EGFR) signaling in murine fibroblasts and A431 cells through a mechanism involving Src kinase. While studying the effects of zinc ions in normal human bronchial epithelial cell, we uncovered evidence for an additional mechanism of Zn(2+)-induced EGFR activation. Exposure to Zn(2+) induced phosphorylation of EGFR at tyrosine 1068, a major autophosphorylation site, in a dose- and time-dependent fashion. This effect of Zn(2+) on EGFR was significantly blocked with an antibody against the ligand-binding domain of the receptor. Neutralizing antibodies against EGFR ligands revealed the involvement of heparin-binding EGF (HB-EGF) in Zn(2+)-induced EGFR phosphorylation. This observation was further supported by immunoblots showing elevated levels of HB-EGF released by Zn(2+)-exposed cells. Zymography showed the existence of matrix metalloproteinase-3 in Zn(2+)-challenged cells. Incubation with a specific matrix metalloproteinase-3 inhibitor suppressed Zn(2+)-induced EGFR phosphorylation as well as HB-EGF release. Therefore, these data support an autocrine or paracrine mechanism whereby Zn(2+) induces EGFR phosphorylation through the extracellular release of EGFR ligands, which may be mediated by metalloproteinases.     

EGFR单克隆抗体抗结肠癌作用的实验研究

目的:观察表皮生长因子受体单克隆抗体(EGFRMcAb)对结肠癌的作用。方法:用不同剂量的EGFRMcAb处理LST174结肠癌细胞系, 采用细胞计数、生长曲线测定及MTT法测定体外培养细胞的生长和增殖抑制率。结果:可见一定程度的增殖抑制并呈剂量依赖性。抗-EGFR抗体组细胞数明显低于对照组(P<0.01).不同浓度之间比较:当EGFRMcAb为0.625mL/L时细胞计数相对高, 是对照组的61.3%;当EGFRMcAb为2.5mL/L时细胞计数最低, 是对照组的33.8%.EGFRMcAb组细胞生长受到抑制, 细胞生长曲线较对照组速度减慢。MTT值显示实验组细胞增殖能力低于对照组, 抑制率为42.3%(P<0.01).结论:EGFRMcAb可抑制人结肠癌LST174细胞生长, 具有一定的抗结肠癌作用。     

Keratinocyte growth factor and epidermal growth factor can reverse the intestinal atrophy associated with elemental diets in mice

Elemental diets are associated with intestinal atrophy and reduced intestinal integrity. Growth factors such as keratinocyte growth factor (KGF) and epidermal growth factor (EGF) have considerable potential for the therapeutic reversal of such atrophy and may have greater actions if given in combination. We examined the effects of recombinant human KGF (rHuKGF), EGF and their combination on tissue mass, cell proliferation and crypt fission throughout the intestine of mice fed elemental diets. rHuKGF significantly increased the relative wet weight of the intestine, with EGF having a lesser effect. Cell proliferation of the stomach, small intestine and colon were significantly increased by rHuKGF, but EGF only increased proliferation in the small intestine. Crypt fission in the small intestine and colon was significantly decreased by rHuKGF. An interactive effect of rHuKGF and EGF on the weight of stomach and the proliferation of the fundus and antrum was observed. Moreover, an interactive effect of the agents was also seen on crypt fission in the colon. We concluded that (1) rHuKGF and EGF have significant trophic effects on the stomach, small intestine and colon, (2) these actions vary between different sites in the gastrointestinal tract, and (3) interactive effects occur.     

Atopy is a risk factor for non-steroidal anti-inflammatory drug sensitivity.

BACKGROUND: There is scarce information in the literature about a possible association between atopy and certain clinical manifestations of NSAID sensitivity. OBJECTIVES: (1) To evaluate the prevalence of atopy in patients proved to be sensitive to cyclooxygenase inhibitors. (2) To assess cross-reactivity to two alternative NSAIDs, paracetamol (acetaminophen) and nimesulide. METHODS: NSAID-sensitive patients attending an allergy clinic and unselected controls were prick tested with inhalant allergens. Oral challenges with NSAIDs were carried out by the single-blinded (SBOC) method. Clinical data about personal and family history of allergic and atopic diseases were obtained by a careful review of the medical records and by direct questioning by experienced allergists. RESULTS: Fifty patients had positive SBOCs to the suspected NSAID and only these were studied. A personal history of atopic diseases was present in 41 patients (82%) and 7 controls (14.5%), and a family history in 24 patients (48%) and 6 controls (12.5%). Prick skin tests with aeroallergens were positive in 39 of 45 patients tested (86.6%) and in 14 of 48 controls (29.1%), (P = .0001). Skin test positivity rates were higher in patients with cutaneous challenge reactions who responded to only one NSAID (single reactors) in comparison to cross-reactors (P = .04). The most frequent clinical manifestations of NSAID sensitivity were (1) cutaneous (angioedema, urticaria) in 34 patients, (2) blended (cutaneous plus respiratory) in 12, (3) respiratory in 3, and (4) anaphylactoid in 1. Aspirin, pyrazolone, paracetamol, and ibuprofen were the drugs more frequently implicated in these reactions. Cross-sensitivity with paracetamol and nimesulide were 32% and 25%, respectively. CONCLUSIONS: The prevalence of atopy is increased in challenge-proven NSAID-intolerant patients. The atopic condition may represent an important risk factor for developing reactions to these drugs. Paracetamol and nimesulide are relatively safe alternative choices in those patients, although their use still carries some risk of unwanted reactions.     

表皮生长因子的研究进展

表皮生长因子具有广泛的促丝裂增殖的作用。本文就其近年来的研究进展 ,包括其分子结构、合成与释放、调控因素、受体 ,以及对神经、消化、呼吸、生殖等多系统的生物学作用等方面的内容作一综述     

Effect of epidermal growth factor on rat stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine

The effect of epidermal growth factor (EGF) on rat stomach carcinogenesis induced by N-methyl-N'-nitro-N-nitro-soguanidine (MNNG) was studied. Male Wistar rats given MNNG for 30 weeks in drinking water (80 micrograms/ml) were treated with s.c. injections of human EGF (10 micrograms/kg, once daily) at various stages of the carcinogenesis. Four (30.8%) out of 13 rats treated with EGF immediately after cessation of the MNNG treatment had stomach tumors including one adenocarcinoma, one adenoma and two carcinoids. No stomach tumor was found in rats treated with MNNG alone or in those treated with MNNG and EGF for different periods such as synchronously for 10 weeks, for 30 weeks or throughout the experiment. These findings suggest a possible enhancing effect of EGF on stomach carcinogenesis in rats.     

Gastritis in patients on non-steroidal anti-inflammatory drugs

This study investigated the spectrum of gastric mucosal pathology, including the prevalence of reactive gastritis in patients on non-steroidal anti-inflammatory drugs (NSAIDs). The histological findings were correlated with upper gastrointestinal symptom status and endoscopic findings and were also compared with the histological appearances of the gastric mucosa in a corresponding age-matched control group of 75 patients not receiving NSAIDs or any other drug therapy. Reactive gastritis of the gastric antrum was more common in the NSAID group and was observed in 34 patients (45.3%), as an isolated phenomenon in 24 patients (32%) and with evidence of coexistent chronic gastritis in 10 patients (13.3%). In the control group reactive gastritis of the antrum was seen in 10 patients (13.3%), as an isolated finding in eight cases (10.7%) and with accompanying chronic gastritis in two cases. Chronic antral gastritis of usual type was observed in 36 patients on NSAIDs (48%) and Helicobacter -like organisms were identified histologically in 18 of these (50% carriage rate). These organisms were not seen in any of the patients in whom the picture of reactive gastritis was present. In the control group chronic antral gastritis was seen in 51 patients (68%) with organisms in 34 (66.6% carriage rate). No correlation was found between the presence or absence of upper gastrointestinal symptoms, endoscopic findings and the histological appearances of the gastric mucosa. We conclude that NSAIDs are an independent cause of reactive gastritis in the antrum and do not appear to alter gastric mucosal colonization by Helicobacter -like organisms. However, the changes of reactive gastritis, of whatever cause, appear to produce a local micro-environment, hostile to these organisms.     

Effect of non-steroidal anti-inflammatory drugs on glutathione levels in various organs of rat

Since glutathione (GSH) depletion (about 20% of total GSH content) can impair the cell's defence against the toxic actions of drugs and may lead to cell injury and death, we examined the effect of piroxicam, naproxen and ketoprofen on GSH levels in various organs of the rat (brain, eye, liver, stomach, heart, leg adductor muscle). Ketoprofen in brain and leg adductor muscle dramatically decreases the GSH levels, giving rise to potential cellular toxicity.

     

Effects of non-steroidal anti-inflammatory drugs on lymphocyte activation

Guinea-pig lymph node lymphocytes were stimulated with mitogen (phytohaemagglutinin)in vitro and lymphocyte activation was measured by tritiated thymidine incorporation (DNA synthesis). Inclusion of non-steroidal anti-inflammatory drugs (NSAIDs) in the culture medium at therapeutic concentrations, frequently exerted an inhibitory effect. Such inhibition could be not attributed to the ability of these drugs to inhibit cyclo-oxygenase or lipoxygenase enzymes. Inhibition by salicylates was not associated with cytotoxic or cytopathic effects, since inhibition was only evident when the drugs were included in the early phase of culture. Other NSAIDs exhibited varying degrees of toxicity, which in some instances may account for observed inhibition. The effects on lymphocyte activation of selective inhibitors of pathways of arachidonic acid metabolism, do not support the proposition that the generation of prostaglandins, thromboxanes, leukotrienes or related compounds is an obligatory step during lymphocyte activation.     

球囊损伤对动脉表皮生长因子受体表达的影响

目的;观察球囊损伤对动脉平滑肌细胞（ＳＭＣ）表皮生长因子受体（ＥＧＦＲ）表达的影响,探讨ＥＧＦＲ与再狭窄的关系。方法：于兔右颈总动脉球囊损伤前及损伤后２４ｈ、４８ｈ、７２ｈ、７天和１４天,取实验动脉段用免疫组化ＬＳＡＢ法检测ＥＧＦＲ的表达。结果：正常叫动脉中膜未见ＥＧＦＲ阳性表达,动脉球囊损伤后２４ｈ中膜部分ＳＭＣ显示ＥＧＦＲ阳性表达。４８ｈ中膜呈ＥＧＦＲ阳性表达的ＳＭＣ较２４ｈ增加,７２ｈ又较４     

Renal toxicity of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs represent the most heavily prescribed and used class of drugs in human medicine. Most are derivatives of either salicylates, propionic acid, indoleacetic acid, anthranilic acid, pyrazolone, or oxicams. They depress the synthesis of prostaglandins from arachidonic acid by reversible inhibition of the enzyme cyclooxygenase. In the kidney, prostaglandins PGE2 and PGI2 modulate the vasoconstrictor effects of angiotensin II, norepinephrine, and vasopressin. In the presence of volume contraction, anesthesia, or disease states associated with high levels of these hormones, prostaglandins regulate glomerular filtration, vascular resistance, and renin secretion. They additionally influence urine volume and sodium content. In man, a syndrome of analgesic abuse that has been identified worldwide occurs more frequently in females than males and can result in severe renal damage, most notably renal papillary necrosis. Most common laboratory animals are relatively resistant to developing the renal lesion associated with NSAIDs unless high doses are given over long periods of time and some withholding of water is introduced into the protocol. Diuresis with 5% dextrose and water is protective. Studies of paracetamol and salicylate have demonstrated that these compounds concentrate in the papillary tip of the kidney at concentrations of 4 to 13 times the plasma levels in dogs and rabbits, respectively. Renal papillary necrosis has been described in horses on maintenance doses of phenylbutazone where dehydration or reduced water consumption has occurred. The lesion can be reproduced experimentally if water is withheld during a portion of the dosing interval. An increased incidence of uroepithelial tumors have been reported in patients with a history of analgesic abuse.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of non-steroidal anti-inflammatory drugs on glutathione levels in various organs of rat

Since glutathione (GSH) depletion (about 20% of total GSH content) can impair the cell's defence against the toxic actions of drugs and may lead to cell injury and death, we examined the effect of piroxicam, naproxen and ketoprofen on GSH levels in various organs of the rat (brain, eye, liver, stomach, heart, leg adductor muscle). Ketoprofen in brain and leg adductor muscle dramatically decreases the GSH levels, giving rise to potential cellular toxicity.     

No association between epidermal growth factor and epidermal growth factor receptor polymorphisms and nasopharyngeal carcinoma

Numerous candidate genes have been proposed as susceptibility factors for the development of nasopharyngeal carcinoma (NPC). Epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) interaction plays a pivotal role in cell proliferation, differentiation, and tumourigenesis of epithelial tissues. To our knowledge, however, no study has examined the relationship between the EGF/EGFR and NPC. The aim of this study is to investigate the potential association between single-nucleotide polymorphisms of EGF +61 G/A and EGFR +2073 A/T and NPC. A total of 173 patients with NPC and 206 age- and sex-matched controls were the participants. Genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism strategy and DNA sequencing. There were no significant differences in the genotype and allele frequencies of EGF +61 G/A and EGFR +2073 A/T polymorphisms between the group of patients with NPC and the control group in a Chinese population (for EGF +61 G/A: OR=1.29, 95% CI: 0.95-1.74; for EGFR +2073 A/T: OR=0.91, 95% CI: 0.67-1.23). Further studies are still needed to explore the complicated interaction between environmental factors and EGF +61 G/A and EGFR +2073 A/T polymorphisms in the risk of NPC, particularly in ethnically different populations.     

唾液中表皮生长因子含量测定

采用放射免疫测定方法,分别检测了46位受试者的混合唾液、腮腺唾液和颌下腺舌下腺混合唾液内的EGF浓度。结果:腮腺唾液EGF为1743～3472Pg/ml,平均 2360±422Pg/ml,比混合唾液EGF高(906～2190pg/ml,平均1604±321pg/ml,P<0.01),也比颌下腺舌下腺混合唾液的含量高(427～816pg/ml,平均627±107pg/ml,P<0.O1)。3组唾液在两性中的差异无显著,但40岁以上唾液EGF含量较低,它与40岁以下者之间的差异有显著(P<0.05)。结果说明唾液中EGF主要来源于腮腺,而与以往普遍认为来源于颌下腺的看法不同。     

Cardiovascular complications of non-steroidal anti-inflammatory drugs

Coxibs, such as rofecoxib, celecoxib, and valdecoxib, selectively inhibit cyclooxygenase (COX)-2, the mainly inducible, pro-inflammatory COX isoform. Unlike traditional non-steroidal anti-inflammatory drugs (NSAIDs) most coxibs do not significantly inhibit COX-1 and are therefore less toxic to the gastrointestinal tract. Hence, coxibs widely replaced traditional NSAIDs for treatment of arthritis and other painful inflammatory conditions. In many, but not all, clinical studies, coxibs became associated with higher risks of myocardial infarction (MI) and stroke. Several mechanisms may be involved in the pathogenesis of such complications. First, selective inhibition of COX-1 lowers platelet synthesis of thromboxane (TXA(2)), a thrombogenic and atherogenic eicosanoid. Selective inhibition of COX-2 limits endothelial cell synthesis of prostacyclin (PGI(2)), an arachidonic acid product that opposes the effects of thromboxane. In apoE-/- mice, interruption of TXA(2) signaling by deletion of its receptor (TP) limits atherogenesis, whereas interruption of PGI2 signaling by deletion of its receptor (IP) accelerates atherogenesis. This suggests that selective inhibition of COX-2 can disrupt the physiological balance between thromboxane and prostacyclin and thus increase atherosclerosis, thrombogenesis, and the risk of cardiovascular complications. Second, COX inhibition can raise levels of arachidonic acid, which can inhibit mitochondrial oxidative phosphorylation (OXPHOS) and increase OXPHOS generation of reactive oxygen species. Several NSAIDs, including coxibs and meloxicam, directly uncouple or inhibit OXPHOS. Studies of apoE-/- mice indicate that mitochondrial dysfunction plays an early role in atherogenesis. Third, many NSAIDs exhibit COX-independent properties. For example, in animal models, short-term treatment with celecoxib reduces monocyte chemotaxis by reducing expression of monocyte chemoattractant protein (MCP)-1. However, long-term treatment results in the opposite effect and accelerates atherogenesis. In conclusion, to reduce the risk of cardiovascular complications during long-term coxib therapy, low-dose aspirin supplementation should be considered. An alternative is to use a less COX-2-selective inhibitor such as meloxicam. Genotyping of -765 alleles of the COX-2 gene promoter and examining the polymorphism of other genes involved in eicosanoid metabolism or NSAID degradation may become helpful in predicting patients who are at higher risk of cardiovascular complications during selective COX-2 inhibitor therapy.     

Effect of blood collection tube types on the measurement of human epidermal growth factor

We observed significant differences in measured human epidermal growth factor (hEGF) levels for the same individual's serum/plasma samples between different tube types (glass, polystyrene, plastic with clot activator, plastic without clot activator, plastic with EDTA, polypropylene tubes). For all individuals, hEGF levels in plasma were found to be below the detection limit. The discrepancy of the hEGF levels in serum and plasma was attributed to the platelet derived EGF by analyzing platelet lyzate with size exclusion chromotography and demonstrating the immunoreactivity of the fractions corresponding to the pre-proEGF and/or proEGF elution time. Besides, samples of females showed much higher EGF levels than those of males in certain test tube types. As a conclusion, all blood samples should be taken and stored in the same type of test tubes in order to make precise measurements for hEGF. And, the measured hEGF level in blood is susceptible to changes with blood clotting.     

表皮生长因子与谷氨酰胺对大鼠乙酸性结肠炎的影响

本研究通过对大鼠结肠粘膜组织学观察，过氧化脂质，髓过氧化物酶，谷胱甘肽过氧化物酶及其线粒体ＡＴＰａｓｅ水平的检测，旨在探讨表皮生长因子和谷氨酰胺防治大鼠乙酸性结肠炎的机理。结果表明：（１）ＥＧＦ组，ＧＬＮ组及ＥＧＦ＋ＧＬＥ组结肠粘膜损伤指数均明显低于乙酸组；光镜，透射及扫描电镜观，ＥＧＦ＋ＧＬＮ组结肠粘膜炎症明显轻于其余３组。（２）ＥＧＦ组，ＧＬＮ组和ＥＥＧＦ＋ＧＬＮ组ＬＰＯ，ＭＰＯ水平分别；明显