Systemic treatment with epidermal growth factor in pigs induces ductal proliferations in the pancreas.

BACKGROUND & AIMS: Epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and the EGF receptor are often overexpressed in chronic pancreatitis and in malignant pancreatic growth. Transgenic mice overexpressing TGF-alpha develop tissue changes in the pancrease resembling changes found in chronic pancreatitis. The effects of systemic treatment with EGF on the porcine pancrease were investigated in this study. METHODS: Mature Goettingen minipigs were treated with solvent (n = 5), EGF (30 micrograms.kg-1.day-1; n = 6) for 4 weeks, or EGF (30 micrograms.kg-1.day-1; n = 5) for 5 weeks followed by 3 weeks of recovery. Pancreata were studied by routine histological examination and electron microscopy and were immunostained for proliferating cell nuclear antigen (PCNA). RESULTS: In the EGF-treated animals, mainly larger interlobular ducts of the pancreas appeared to be considerably hyperplastic, with an increased number of nuclei that stained for PCNA. The epithelia of these ducts were increased in height, with accumulations of glycoconjugates in the columnar cells and in an increased number of goblet cells. CONCLUSIONS: A new approach to experimentally induced hyperplastic changes of the excretory ducts of the pancreas is presented. Because ductal changes with glycoconjugate accumulations are common features of chronic pancreatitis and pancreatic cancer, the findings may be relevant to the pathogeneses of these conditions.

Chronic systemic treatment with epidermal growth factor induces smooth muscle cell hyperplasia and hypertrophy in the urinary tract of mature Goettingen minipigs.

OBJECTIVE: To determine the effect of systemic treatment with epidermal growth factor (EGF) on the induction of growth in the urinary tract. MATERIALS AND METHODS: Mature Goettingen minipigs were treated daily with vehicle (Tris-HCl; n = 5) or EGF (30 micrograms/kg) (n = 6) for 4 weeks. The total number of smooth muscle cells was counted using an optical disector in a 20 microns thick cross-section of the ureter and the mean smooth muscle cell volume estimated. Cell proliferation was detected by immunostaining for the marker Ki67. RESULTS: The ureters of the animals treated with EGF were longer and thicker than those of the controls and the median cross-sectional area of the ureter was 3.3-fold larger; the growth involved all wall layers. The median (range) number of smooth muscle cells in a 20 microns thick cross-section of the ureter was 11 (9-12) x 10(3) in the pigs treated with placebo and 55 (19-80) x 10(3) in those treated with EGF, and the median (range) volume of the smooth muscle cells was 2.3 (2.2-2.4) x 10(3) and 4.0 (3.0-4.5) x 10(3) mm3, respectively. CONCLUSIONS: There were two likely mechanisms contributing to smooth muscle cell hyperplasia, the division of fully differentiated smooth muscle cells and division of fibroblasts in the borderline between the submucosal layer and muscular coat, with ensuing differentiation into smooth muscle cells. Treatment with EGF induces the growth of all wall layers in the urinary tract with remarkable hyperplastic and hypertrophic changes of the smooth muscle cells in the muscular coat.

The effect of epidermal growth factor on circulating levels of IGF and IGF-binding proteins in adult Goettingen minipigs.

It has recently been demonstrated that epidermal growth factor (EGF) administration to neonatal rodents causes growth retardation with concomitant reductions in circulation levels of IGF-I. We describe the effects of systemic EGF administration for 4 weeks on circulating levels of IGF-I and IGF-binding proteins (IGFBPs) and on thyroid hormones (tri-iodothyronine, T3; thyroxine, T4) in sexually mature pigs. Goettingen minipigs of either sex were treated with placebo (n = 5) or EGF (30 micrograms/kg per day, n = 6) s.c. for 4 weeks (in relation to an oesophageal sclerotherapy regimen). Blood samples were taken under anaesthesia before and after 1, 2, 3 and 4 weeks of treatment. Circulating levels of IGF-I, insulin, glucose, T3 and T4 were analysed every week and IGFBPs every second week. IGF-I was not reduced significantly after 1 week but significantly reduced after 2 and 3 weeks of EGF treatment. A similar decline was observed for the major IGFBP, IGFBP-3, which was reduced after 2 and 4 weeks. IGFBP-1, IGFBP-2 and IGFBP-4 increased throughout the treatment period (all significantly at week 4). EGF treatment induced increased circulating T3 after 2, 3 and 4 weeks of EGF treatment. In conclusion, we report that EGF treatment for 4 weeks in Goettingen minipigs reduces circulating IGF-I and IGFBP-3, increases circulating IGFBP-1, IGFBP-2 and IGFBP-4, and induces a slight hyperthyroidism as judged from increased circulating levels of T3.

Impedance planimetric characterization of the distal oesophagus in the Goettingen minipig.

Regional differences in biomechanical properties of the oesophagus were studied in 15 healthy Goettingen minipigs by means of impedance planimetry. The investigation was performed during anaesthesia by stepwise pressure-induced balloon distensions with concomitant measurement of pressure and luminal cross-sectional area (CSA) in the oesophagus 5 and 10 cm above the gastro-oesophageal junction. The circumferential wall tension, circumferential strain and incremental elastic modulus were computed from the measurements of pressure and CSA at steady-state conditions. Probably due to the anaesthesia, only scant peristalsis was recorded and the CSA always reached steady state during the balloon distensions. The CSAs were highest in the distal oesophagus (P < 0.001). At the highest induced pressure, the CSAs were 605 +/- 32 and 453 +/- 29 mm2 (mean +/- SEM) for the locations 5 and 10 cm from the gastro-oesophageal junction. The tension-strain distributions were non-linear and the curve obtained 5 cm above the gastro-oesophageal junction was shifted to the right when compared with the curve obtained from 10 cm above this junction. Fitting of the function tension = exp(a+b strain) to the data gave determination coefficients higher than 0.97 and P values lower than 0.001 for both measuring points. The constant a differed between the two locations in the oesophagus (P < 0.05). In conclusion, the pressure-CSA and the tension-strain distributions differed between the two measuring points suggesting that the elastic properties are different.

Chronic treatment with epidermal growth factor stimulates growth of the urinary tract in the rat.

Twenty-four male Wistar rats, 8 weeks old, were allocated into three groups and treated with human recombinant epidermal growth factor (EGF) administered subcutaneously in doses of 0, 30, and 150 micrograms/kg per day for 4 weeks. Blood sampling was done every 2nd week and urine sampling was done for 2 consecutive days every week. The most striking finding was that the ureters were dose dependently enlarged, due to growth of all layers of the ureteric wall. The urothelium of the bladder showed considerable hyperplasticity with a widening of the basal proliferative compartment and a normal differentiation pattern as observed by the expression of carbohydrate epitopes, characterized with lectinohistochemistry. Blood examination revealed a decrease in blood haemoglobin concentration and a slight increase in serum creatinine concentration in the high-dose group. There were no effects of EGF on the urinary excretion of electrolytes, proteins, and endogenous EGF.

Chronic treatment with epidermal growth factor causes esophageal epithelial hyperplasia in pigs and rats.

Epidermal growth factor (EGF) is an important factor for maintaining the esophageal functional integrity. Goettingen minipigs were treated with either placebo or subcutaneous EGF (30 micrograms/kg/day) for four weeks. Wistar rats were treated with either placebo or subcutaneous EGF (150 micrograms/kg/day) for four weeks. At sacrifice, esophageal samples were obtained for histology, immunochemistry, and lectin characterization. In pigs, the thickness of the esophageal epithelium was almost doubled in the EGF-treated animals. Characterization with lectins revealed a normal pattern of differentiation. Subcutaneously administered EGF was visualized on cells located basally in the esophageal epithelium. In rats, EGF-treatment increased the esophageal volume of the epithelium, the lamina propria of the mucosa, and the submucosa. In conclusion, systemic EGF challenge induces growth of the esophageal epithelium with an unaltered pattern of differentiation. This supports previous studies demonstrating a beneficial effects of systemic EGF-treatment on sclerotherapy-induced esophageal damage.

Chronic administration of epidermal growth factor to pigs induces growth, especially of the urinary tract with accumulation of epithelial glycoconjugates.

BACKGROUND: Epidermal growth factor (EGF) receptor hyperstimulation induced by systemically administered EGF or by the development of transgenic mice overexpressing transforming growth factor alpha (TGF alpha) or other EGF-related ligands is known to induce various effects, such as acceleration of developmental processes like incisor eruption, inhibition of gastric acid secretion, morphologic changes in the pancreas resembling pancreatitis, and malignancies in mammary glands and the liver. The present investigation was initiated to explore the effects of systemic EGF administration to the mature organism in a species with greater anatomic resemblance to humans than rodents. EXPERIMENTAL DESIGN: Eleven Goettingen Minipigs underwent 4 weeks of treatment either with placebo (n = 5) or human recombinant EGF 30 micrograms/kg/day (n = 6) administered subcutaneously. At the end of Week 4, the animals were sacrificed, autopsy was performed, and tissue samples were collected for histologic examination. RESULTS: EGF treatment caused macroscopic enlargement of the ureters, kidney, and heart. The ureters increased 4-fold in cross sectional area due to growth of all wall layers. The urothelium was hyperplastic with intracellular accumulations of material staining with Periodic acid-Schiff. Similar but less pronounced changes were found in the pancreas, lungs, salivary glands and esophagus. CONCLUSIONS: The most important observation of the present study is that systemic treatment with EGF for 4 weeks induces considerable growth to the urinary tract. We suggest new biologic effects of the EGF family in promoting growth of the urinary tract and in stimulating epithelial glycoconjugate biosynthesis in the urothelium and excretory ducts of the pancreas.

Chronic systemic treatment with epidermal growth factor in pigs causes pronounced urothelial growth with accumulation of glycoconjugates.

Epidermal growth factor (EGF) is present in large amounts in the urine, but the effects of systemically administered EGF on the urinary tract have not been described previously. In the present paper, we describe a potent growth induction of EGF on the urinary tract. Goettingen minipigs were treated with solvent (n = 5), EGF 30 micrograms/kg/day (n = 6) for 4 weeks, or EGF 30 micrograms/kg/day for 5 weeks followed by 3 weeks of recovery (n = 5). The ureters and bladders were examined by routine histology and electron microscopy and were immunostained for proliferating cell nuclear antigen. Four weeks of EGF treatment increased the median cross sectional area of the ureter fourfold with growth of all wall layers. The urothelium was widened from 5 cell layers in the controls to 10 in the EGF-treated animals. Proliferating cell nuclear antigen immunostaining revealed an increased mitotic activity in the basal zone of the urothelium. In the luminal zone, glycoconjugates accumulated in goblet cells, in cells with intracytoplasmic lumina, and beneath the luminal cell membrane in the umbrella cells. Our studies present a new experimental approach to growth induction of the urinary tract. The findings implicate the EGF system in regulating urothelial growth and glycoconjugate biosynthesis.

Systemic treatment with epidermal growth factor induces anaemia in Goettingen minipigs.

1. From two independent experimental studies conducted in 48 minipigs with oesophageal sclerotherapy and concomitant treatment with epidermal growth factor, blood samples together with bone marrow biopsies were analysed for safety data. 2. Four to five weeks of systemic treatment with epidermal growth factor induced a decline in blood haemoglobin concentration in a time- and dose-dependent and reversible manner but without an effect on leucocyte or platelet counts. 3. The bone marrow expressed decreased amounts of haematopoietic tissue and reduced numbers of erythropoietic cells. 4. Four to five weeks of systemic treatment with epidermal growth factor induced reversible increases in serum concentrations of creatinine and urea, most likely reflecting renal impairment. 5. Groups in which creatinine and urea were not increased also had reduced blood haemoglobin concentrations. 6. These findings suggest that epidermal growth factor selectively impaired the erythropoiesis and stress the importance of risk-benefit analysis concerning the potential therapeutic applications of epidermal growth factor.

Preventive effects of recombinant human epidermal growth factor on the oesophageal epithelium in pigs subjected to sclerotherapy.

OBJECTIVE: To investigate the role of epidermal growth factor (EGF), a small (relative molecular mass 6000) polypeptide with mitogenic properties in the protection of gastrointestinal mucosal integrity. DESIGN: A prospective, randomized and blinded study. METHODS: Twenty-four minipigs with surgically induced portal hypertension underwent four consecutive weekly sessions of oesophageal sclerotherapy with 5 ml 1% polidocanol and were concomitantly treated with either a placebo or human recombinant EGF administered subcutaneously. Mucosal damage was evaluated on a weekly basis by endoscopic estimation of the size of the ulcerated area and by post-mortem morphometry. The EGF-induced morphological changes in the oesophageal epithelium were also evaluated histologically. RESULTS: In sclerosed and non-sclerosed parts of the oesophagus EGF significantly increased the thickness of the oesophageal epithelium (P < 0.03), but failed to reduce significantly the degree of oesophageal damage associated with sclerotherapy (P = 0.11). CONCLUSIONS: Systemic EGF treatment induces proliferation of the oesophageal mucosa, and EGF may therefore have the potential to reduce sclerotherapy-induced oesophageal damage.

Epidermal growth factor attenuates the sclerotherapy-induced biomechanical properties of the oesophagus. An experimental study in minipigs.

BACKGROUND: The effect of epidermal growth factor (EGF) on the biomechanical properties of the oesophagus subjected to sclerotherapy was studied in Goettingen minipigs by means of impedance planimetry. METHODS: Seventeen animals underwent three sessions of weekly endoscopic sclerotherapy. During these 3 weeks and for the subsequent 2 weeks they were treated with either EGF or placebo. After another 3 weeks an impedance planimetric study was done. Ten healthy non-sclerosed pigs were studied as controls. Impedance planimetry was performed by stepwise pressure-induced balloon inflation for analysis of oesophageal cross-sectional area 5 and 10 cm above the gastro-oesophageal junction (GEJ). RESULTS: Systemic treatment with EGF (total daily dose of 30 micrograms/kg/day, administered subcutaneously) for 3 to 7 days per week combined with a weekly paravenous injection of 20-40 micrograms/kg attenuated the oesophageal damage caused by sclerotherapy, implying less pronounced narrowing 5 cm above and less dilation 10 cm above the GEJ. CONCLUSION: These observations suggest a potential therapeutic role for EGF in attenuating sclerotherapy-induced oesophageal injury.

Chronic systemic treatment with epidermal growth factor induces hypergastrinaemia in Goettingen minipigs.

BACKGROUND: Epidermal growth factor (EGF) is an inhibitor of gastric acid secretion. The impact of chronic systemic treatment with EGF on intragastric pH and serum gastrin concentrations has not been investigated previously. METHODS: Goettingen minipigs were treated with human recombinant EGF (hEGF) or placebo for 4 weeks. Once a week the acidity and protein concentration of gastric juice were determined, and serum gastrin concentrations measured. After 4 weeks, tissue specimens were obtained from the gastric antrum and immunostained for gastrin- and somatostatin-producing G- and D-cells. Furthermore, the development of antibodies against hEGF was evaluated. RESULTS AND CONCLUSION: Subcutaneously administered hEGF, 30 micrograms/kg/day for 4 weeks, included a fourfold increase in basal serum gastrin concentration, increased the number of antral G-cells, and decreased the density of antral D-cells. The acidity of gastric fluid was reduced, and the protein concentration increased. All animals developed low-titred antibodies towards hEGF. The antibodies did not influence the extent to which the individual animal responded to the EGF treatment.

Ureteric growth in a Goettingen minipig induced by epidermal growth factor. A case report.

We have recently discovered that prolonged systemic administration of epidermal growth factor (EGF) induces a remarkable growth of all wall layers of the urinary tract in minipigs. In the present paper, we report the most pronounced changes induced by 4 weeks of systemic EGF challenge in two pigs treated for four weeks with either solvent or EGF (30 micrograms/kg/day), respectively. The EGF treated ureter was longer and thicker with an approximately four fold increase in diameter. All wall layers were enlarged. The urothelium was increased from 5 to 10 cellular rows with basal hyperplasia and an increased number of goblet cells and cells with intracytoplasmic lumina in the luminal half. In the muscular coat, the bundles of hypertrophied cells and intervening connective tissue were enlarged. The present paper suggests a possible in vivo approach to increase the amount of tissue needed in reconstructive surgery of the urinary tract.

Systemic treatment with recombinant human epidermal growth factor accelerates healing of sclerotherapy-induced esophageal ulcers and prevents esophageal stricture formations in pigs.

Human epidermal growth factor (EGF), a small polypeptide (6 kDa) with mitogenic properties, has been implicated in the protection of gastrointestinal mucosal integrity. The efficacy of EGF in the prevention and healing of sclerotherapy-induced esophageal lesions was investigated in 24 minipigs with surgically induced portal hypertension. In addition, the effect of EGF on intragastric acidity and pharmacokinetics was investigated as possible means to explain its protective mechanism of action. The animals underwent three weekly sessions of sclerotherapy with polidocanol 2% and were concomitantly and for an additional three weeks treated with either placebo or EGF administered paravenously in the esophagus and/or subcutaneously. The subcutaneous treatment with EGF significantly (P < 0.05) reduced esophageal stricture and scar formations associated with sclerotherapy. Gastric pH values were significantly (P < 0.01) elevated only in animals receiving subcutaneous injections of EGF. Furthermore, the subcutaneous administration of EGF was associated with unexpected prolonged plasma concentration of the peptide. These results suggest a possible clinical value of EGF as an adjunctive treatment with the sclerotherapy.

Biomechanical properties of the oesophagus damaged by endoscopic sclerotherapy. An impedance planimetric study in minipigs.

BACKGROUND: The aims of the present study were to evaluate, by means of impedance plainmetry, regional differences in biomechanical properties in the normal oesophagus and the oesophagus damaged by sclerotherapy. METHODS: Four minipigs underwent a weekly session of sclerotherapy for 4 weeks. Impedance planimetry was performed before the first session of sclerotherapy and 1 week after the last session of sclerotherapy. Investigations were performed by stepwise pressure-induced balloon distensions with concomitant measurements of pressure and luminal cross-sectional area (CSA) in the oesophagus 5 and 10 cm above the gastro-oesophageal junction (GEJ). RESULTS: The normal oesophagus had significantly larger CSAs 5 cm than 10 cm above the GEJ (P < 0.05). Endoscopic sclerotherapy entailed an inversion (P < 0.05) of the normal oesophageal configuration, with narrowing 5 cm above the GEJ (P < 0.05) and increased CSAs 10 cm above the GEJ (P < 0.05). CONCLUSIONS: Regional differences in CSA occur in the normal oesophagus, and sclerotherapy produces profound changes in the oesophageal configuration.

Recombinant human epidermal growth factor prevents sclerotherapy-induced esophageal ulcer and stricture formations in pigs.

Human epidermal growth factor (EGF), a naturally occurring protein, has been implicated in the protection of gastrointestinal mucosal integrity. The efficacy of EGF in the prevention of sclerotherapy-induced esophageal lesions was investigated in 18 minipigs with surgically induced portal hypertension. The animals underwent five weekly sessions of sclerotherapy with polidocanol 2% and were concomitantly treated with either placebo or EGF administered either paravenously or subcutaneously. EGF significantly (P < 0.05) reduced esophageal ulcerations, stricture formations, and mucosal histological damage associated with sclerotherapy. The drug was well-tolerated with no overt toxicity. These results suggest a potentially important clinical value of EGF as an adjunctive treatment with the sclerotherapy.

[Blood transfusion increases the risk of surgical infection]. / Blodtransfusion øger den kirurgiske infektionsrisiko.

In a prospective randomized trial the frequency of infectious complications and natural killer cell function were investigated in 197 patients undergoing elective colorectal surgery and having either no blood transfusion (n = 93), transfusion with whole blood (n = 56), or filtered blood free from leucocytes (n = 48). Postoperative infections developed in 13 patients transfused with whole blood (23%), in one patient transfused with blood free from leucocytes (2%) and in two non-transfused patients (2%) (p < 0.01). Natural killer cell function was significantly (p < 0.001) impaired up to 30 days after surgery in patients transfused with whole blood. These data provide a strong case against the use of whole blood transfusion in patients undergoing elective colorectal surgery.

Postoperative infection and natural killer cell function following blood transfusion in patients undergoing elective colorectal surgery.

The frequency of infection in 197 patients undergoing elective colorectal surgery and having either no blood transfusion, transfusion with whole blood, or filtered blood free from leucocytes and platelets was investigated in a prospective randomized trial. Natural killer cell function was measured before operation and 3, 7 and 30 days after surgery in 60 consecutive patients. Of the patients 104 required blood transfusion; 48 received filtered blood and 56 underwent whole blood transfusion. Postoperative infections developed in 13 patients transfused with whole blood (23 per cent, 95 per cent confidence interval 13-32 per cent), in one patient transfused with blood free from leucocytes and platelets (2 per cent, 95 per cent confidence interval 0.05-11 per cent) and in two non-transfused patients (2 per cent, 95 per cent confidence interval 0.3-8 per cent) (P less than 0.01). Natural killer cell function was significantly (P less than 0.001) impaired up to 30 days after surgery in patients transfused with whole blood. These data provide a strong case against the use of whole blood transfusion in patients undergoing elective colorectal surgery.

Time course of development of changes in the structure and reactivity of small veins from portal hypertensive rabbits.

1. Myographic and histological techniques were used to study the mechanical and morphological properties of oesophageal and mesenteric veins from rabbits subjected to 0, 4, 14 and 90 days of partial portal vein stenosis. 2. The stenosis caused an immediate increase in portal pressure from 10.5 mmHg (1.4 kPa) to 20.5 mmHg (2.7 kPa); the pressure returned to the control level by 90 days. 3. The lumen diameter of oesophageal veins was increased by 76% after 4 days and by 147% after 90 days, while that of the mesenteric veins was unchanged. The media thickness in both veins increased rapidly, reaching a maximum at 14 days (82%, oesophageal; 56%, mesenteric) and thereafter decreasing. 4. The contractility of oesophageal veins was transiently decreased (at 4 days), while that of the mesenteric veins was transiently increased (at 14 days). 5. In further experiments, sclerosing of the oesophagus, which is believed to restrict flow without reducing pressure, restricted the increase in lumen diameter of oesophageal veins caudal to the sclerosing site, but did not affect the media thickness. 6. The results suggest that, in oesophageal and mesenteric veins, portal pressure is a primary determinant of media thickness but not of lumen diameter.

Endoscopic, portographic, and hemodynamic evaluation of prolonged propranolol administration in pigs with experimental portal hypertension and esophageal varices.

The effect of long-term propranolol administration on esophageal varices, portocollateral shunting, portal pressure, hepatosplanchnic hemodynamics, and liver function was studied in a pig model with experimentally induced prehepatic portal hypertension and esophageal varices. Five pigs were treated with 160 mg propranolol daily from week 5 to week 24 after portal-vein banding, and five pigs served as nontreated controls. Administration of propranolol caused an initial, significant reduction (20%) of portal venous pressure, followed by a gradual increase to levels not different from control pressures. In contrast, a marked reduction of the caliber of the coronary vein and size of the esophageal varices was noticed. Twenty weeks of propranolol treatment did not change liver blood flow or liver function. We conclude that the size of the varices rather than portal venous pressure depicts the effect of propranolol treatment and suggest that the beneficial effect of propranolol on variceal bleeding can be explained by a reduction in the wall tension of the varices, initiated and maintained by a diminution of splanchnic blood flow.