Søren Aggestrup

Regulatory peptides in the lower esophageal sphincter of man.

Smooth muscle specimens were taken from the lower esophageal sphincter of patients suffering from achalasia or hiatus hernia with gastro-esophageal reflux. The specimens were analysed for neurohormonal peptides using immunochemistry and immunocytochemistry. Control specimens were obtained from patients subjected to esophageal resection because of esophageal cancer. The concentration of vasoactive intestinal polypeptide (VIP) was higher and the VIP nerve supply greater in patients with hiatus hernia than in control patients. The VIP nerve supply and the content of this peptide was lower in patients with achalasia than in controls. The same tendency was observed for substance P and enkephalin although the changes in their concentrations were not statistically significant. Enkephalin fibers were few, both in specimens from control patients and from patients with hiatus hernia; they could not be detected in specimens from patients with achalasia. Never fibers containing somatostatin or gastrin/cholecystokinin could not be detected in any of the groups and somatostatin and gastrin/cholecystokinin could not be measured in extracts of the lower esophageal sphincter. We propose that changes in the concentration of neuropeptides may at least contribute to manifestations of achalasia and of decreased lower esophageal sphincter pressure and gastro-esophageal reflux.

Regulatory peptides in lower esophageal sphincter of pig and man

Smooth muscle specimens from the lower esophageal sphincter (LES) region of pig and man were analyzed for vasoactive intestinal peptides (VIP), substance P (SP), enkephalin, neuropeptide Y (NPY), gastrin/cholecystokinin (CCK), neurotensin, and somatostatin using immunocytochemistry and radioimmunoassay. VIP-, SP-, enkephalin-, and NPY-immunoreactive nerve fibers were observed in the LES of both species, whereas nerve The peptide-containing nerve fibers occurred in the intramural ganglia and in the smooth muscle layers. There was a rich supply of VIP-and NPY-immunoreactive fibers, whereas the supply of SP-and enkephalin-immunoreactive nerve fibers were moderate in number in both species examined. The concentration of VIP, SP, enkephalin and NPY was comparable in the two species. The present study shows that the pattern of peptidergic innervation of the LES is similar in pig and man. It is proposed that neuronal VIP, SP, enkephalin, and NPY may serve to modulate the motor activity of the LES and that the pig is a suitable experimental animal for the study of regulatory peptides and LES functions.

Eosinophil infiltration in primary esophageal achalasia

Smooth-muscle specimens from the lower esophagus of nine patients operated on for esophageal achalasia were examined with routine hematoxylin-eosin staining. This procedure revealed only a few eosinophils in or between the external smooth-muscle layers. Using specific immunohistochemical methods for the detection of the eosinophil cationic protein (ECP), however, varying degrees of eosinophil infiltration and extracellular deposit of ECP were disclosed in the achalasia specimens. The ECP also reacted with the monoclonal antibody, EG2, indicating secretion of the cytotoxic ECP. Few or no eosinophils were seen in the muscularis externa in specimens from six control patients without esophageal disease. In two controls many eosinophils were observed in the muscularis externa. However, no extracellular ECP was detected and very few eosinophils reacted with the monoclonal antibody (EG2), suggesting that these eosinophils were not activated. Depletion or total absence of peptidergic innervation was seen in all achalasia specimens but not in controls. Since the eosinophil cationic protein (ECP), in its activated form, is cytotoxic, we propose a pathogenic role of the eosinophil infiltration in achalasia.

Computerized 12-hour simultaneous ECG, pressure- and pH-probe investigation of the oesophagus. Method and reference values in healthy individuals

A computerized 12-h simultaneous ECG, pressure- and pH-probe investigation method of the oesophagus is described, and reference values in healthy individuals presented. The analysing system includes two new elements. An interface box, which detects propagating and retrograde peristalsis, by looking at pressures in the oesophagus. A computer (Hewlett Packard 9845T), which makes the whole analysis automatic, draws a 12-h pH-curve, makes area computations, pH-related swallow registrations and time-pH relationships. The results obtained with this measuring system are in agreement with the results of other similar investigations. It is concluded that area computation is the most accurate method of reflux detection. Furthermore this simultaneous ECG, pressure and pH measuring system is excellent in differentiating between chest pain of cardial and oesophageal origin.

Effects of regulatory peptides on the porcine lower oesophageal sphincter.

Studies were performed to investigate the effects of neurotransmitters and neurotransmitter candidates (substance P, VIP, somatostatin, Met-enkephalin, gastrin-17, CCK-4 and -8, neurotensin and TRH) of the newly discovered peptidergic nervous system on lower oesophageal sphincter pressure in anaesthetized pigs. All neuropeptides were infused over 2 min periods in 6 different doses, separated by resting periods of at least 1 min, directly into the arterial supply of the lower oesophageal sphincter. Substance P caused a dose-dependent increase in lower oesophageal shpincter pressure; the threshold dose was 9 pmol . kg-1 . min-1 and half maximal response occurred at 72 pmol . kg-1 . min-1. None of the other polypeptides, however, influenced the resting lower oesophageal sphincter. These studies show that substance P is a potent stimulant of smooth muscle in the lower oesophageal sphincter, suggesting that this peptide may be an important regulator of lower oesophageal sphincter pressure.

Distribution and Content of Neuropeptide Y in the Human Lower Esophageal Sphincter

The occurrence and distribution of neuropeptide Y (NPY) was studied in smooth-muscle specimens from the human lower esophageal sphincter region by immunocytochemistry and immunochemistry. Normal individuals and patients suffering from achalasia or hiatus hernia with severe gastroesophageal reflux were examined. NPY fibers were found within and around smooth-muscle bundles of the longitudinal and the circular muscle layers and within the myenteric ganglia. Smooth-muscle specimens from patients with hiatus hernia and gastroesophageal reflux displayed numerous NPY fibers and an increased content of NPY. Specimens from patients with achalasia contained only few NPY fibers and had a decreased content of NPY as compared to specimens from control patients. Conceivably, NPY may play a role in the regulation of the lower esophageal sphincter.

Effect of regulatory polypeptides on the substance P stimulated lower esophageal sphincter pressure in pigs

The effect of graded doses of vasoactive intestinal polypeptide (VIP), enkephalin, neuropeptide Y (NPY), gastrin-17, pentagastrin, cholecystokinin (CCK)-4, CCK-8, neurotensin, somatostatin, and thyrotropin-releasing hormone (TRH) on the substance P (SP)-stimulated lower esophageal sphincter pressure (LESP) in anaesthetized pigs was studied by direct infusion of the peptides into the arterial supply of the lower esophageal sphincter (LES). Infusion of SP in a dose of 20 pmol/kg per min for 3 min significantly increased the LESP (P less than 0.01). Simultaneous VIP infusion at 5--40 pmol/kg per min showed a dose-dependent inhibition of the effect of SP on the LESP. None of the other peptides had any effect on the LESP during simultaneous infusion of SP. Pharmacological blockade by atropine (250 mu/kg) or guanethidine (1 mg/kg) had no effect on the SP-stimulated LESP. In conclusion, the SP-induced stimulation of the LESP is abolished by VIP, and both peptides seem to play a role in the complex regulation of the LESP.

Brain damage following low flow cardiopulmonary bypass in pigs.

Reduction of pump flow during cardiopulmonary bypass (CPB) reduces the formation of microemboli and trauma to the blood components, reduces both rewarming of the heart and the noncoronary collateral flow, and improves surgical exposure. Recent studies indicate that a reduction in pump flow, even at normothermia, does not increase the incidence of postoperative cerebral dysfunction. We examined the cerebral consequences of 2 h of normothermic CPB in pigs carried out at pump flows of either 70 ml/kg per min or 50 ml/kg per min, and compared the results with those of a nonperfused control group. We measured the regional cerebral glucose metabolism and the regional capillary diffusion capacity simultaneously in ten different brain regions. Brain morphology, the blood-brain barrier permeability to serum proteins and the regional cerebral water content were also determined in the same animals. Glucose metabolism decreased significantly in both CPB groups (P < 0.001), and significant differences were found between the capillary diffusion capacities of the three groups (P < 0.05), with decreases in eight out of ten brain regions examined in the 50 ml/kg per min group. The results indicate that a reduction of pump flows from 70 ml/kg per min to 50 ml/kg per min is deleterious to the brain, and that a pump flow of 70 ml/kg per min itself has an injurious effect, when normothermic CPB is carried out for 2 h without the use of vasoactive drugs to maintain the blood pressure. Mean arterial blood pressure (MAP) rather than pump flow seemed to determine the adequacy of the cerebral perfusion.