Experimental acute pancreatitis in dogs. IV. The relationship between phospholipase A and the histamine-releasing and hypotensive effects of pancreatic exudate

Clinical pancreatology I: Pancreatic medical history

The present article and subsequent reviews will not be to report all what has been published, but rather to give an introduction samples that hopefully make the reader eager to read the whole article or articles with "a taste of clinical pancreatology in 2010". The main sources of literatures were PubMed, and the additional Journals such as Pancreas, Pancreatology and Journal of the Pancreas were also scrutinized. Only some full articles in almost all languages were included in the review, other articles, however, that were too superficial or too poor in other ways, were omitted, and the publications of non-human study were excluded.

Treatment of acute pancreatitis: an attempted historical review

This attempt at a historical review of the treatment of acute pancreatitis summarizes the findings of studies carried out in decades long past and shows their impact on the therapy of this disease today. It identifies in retrospect the correct avenues of research and the blind alleys, and describes the ebb and flow of interest in various forms of management. Acquaintance with the work of previous investigators may prevent the unnecessary rediscovery of old principles of treatment. Not all of the studies discussed can be found with search engines: they come from the author's personal library, collected over his 40 years as an active pancreatologist, and from the knowledge of the early literature bequeathed to him by his teachers and mentors.

Rat paw oedema and mast cell degranulation caused by two phospholipase A2 enzymes isolated from Trimeresurus mucrosquamatus venom

Two phospholipase A2 (PLA2) enzymes, TMVPLA2 I and TMVPLA2 II, isolated from Trimeresurus mucrosquamatus venom (TMV) induce rat hind-paw oedema in a dose-dependent manner. This response is suppressed by pretreatment with diphenhydramine, methysergide or compound 48/80, which reduces tissue histamine content. In isolated mast cells, TMVPLA2 I and TMVPLA2 II cause concentration-, time- and calcium-dependent release of histamine and beta-glucuronidase. This effect is inhibited by disodium cromoglycate, mepacrine, nordihydroguaiaretic acid, piriprost and BW 755C, but not by aspirin or indomethacin. These observations indicate that the mast cell plays a predominant role in TMVPLA2 I- and TMVPLA2 II-induced paw oedema, and that venom PLA2 enzyme needs an intact lipoxygenase pathway to induce mast cell degranulation.

Long peritoneal lavage decreases pancreatic sepsis in acute pancreatitis

Late infection of devitalized pancreatic and peripancreatic tissue has become the major cause of morbidity in severe acute pancreatitis. Previous experience found that peritoneal lavage for periods of 48 to 96 hours may reduce early systemic complications but did not decrease late pancreatic sepsis. A fortunate observation led to the present study of the influence of a longer period of lavage on late sepsis. Twenty-nine patients receiving primary nonoperative treatment for severe acute pancreatitis (three or more positive prognostic signs) were randomly assigned to short peritoneal lavage (SPL) for 2 days (15 patients) or to long peritoneal lavage (LPL) for 7 days (14 patients). Positive prognostic signs averaged 5 in both groups but the frequency of five or more signs was higher in LPL (71%) than in SPL (47%). Eleven patients in each group had early computed tomographic (CT) scans. Peripancreatic fluid collections were shown more commonly in LPL (82%) than in SPL (54%) patients. Longer lavage dramatically reduced the frequency of both pancreatic sepsis (22% LPL versus 40% SPL) and death from sepsis (0% LPL versus 20% SPL). Among patients with fluid collections on early CT scan, LPL led to a more marked reduction in both pancreatic sepsis (33% LPL versus 83% SPL) and death from sepsis (0% LPL versus 33% SPL). The differences were even more striking among 17 patients with five or more positive prognostic signs. In this group the incidence of pancreatic sepsis was 30% LPL versus 57% SPL and of death from sepsis 0% (LPL) versus 43% (SPL) (p = 0.05). In these patients, overall mortality was also reduced (20% LPL versus 43% SPL). When 20 patients treated by LPL were compared with 91 other patients with three or more positive prognostic signs who were treated without lavage or by lavage for periods of 2 to 4 days, the frequency of death from pancreatic sepsis was reduced from 13% to 5%. In those with five or more signs, the incidence of sepsis was reduced from 40% to 27% (p = 0.03) and of death for sepsis from 30% to 7% (p = 0.08). These findings indicate that lavage of the peritoneal cavity for 7 days may significantly reduce both the frequency and mortality rate of pancreatic sepsis in severe acute pancreatitis.

Low dose dopamine protects against hemorrhagic pancreatitis in cats

Acute hemorrhagic pancreatitis (HP) is probably associated with decreased blood flow in its early phases, as well as with an increase in microvascular permeability. Dopamine (DOP; 5 micrograms/kg-min) is a splanchnic vasodilator, and also has beta-adrenergic effects that can prevent increases in microvascular permeability. We hypothesized that low dose dopamine might have beneficial effects on both blood flow and microvascular permeability, thus ameliorating the severity of the disease. We studied its actions in an animal model of HP. In anesthetized cats, intragastric ethanol (20 ml/40% solution) rendered the main pancreatic duct permeable to pancreatic enzymes. Then the duct was perfused from tail to head with 0.5 ml of activated pancreatic enzymes for 1 hr. To create HP, 16,16-dimethyl prostaglandin E2 (2 micrograms/kg-hr, iv) was given for 2 hr to increase blood flow and microvascular permeability. Seven of eight cats developed HP in 24 hr. Control cats received no additional drugs. Two experimental groups received DOP (6 hr infusion) begun either (1) at the onset of enzyme perfusion or (2) 12 hr later. Each pancreas was examined after 24 hr and graded (1-4) histologically for edema, hemorrhage, polymorphonuclear cell infiltrate, and architectural loss. An inflammatory score (IS) from 0 to 16 was thus created (higher scores = greater damage). The results showed an IS of 10.9 +/- 1.8 for the controls, 3.3 +/- 0.5 for the immediate treatment group, and 7.2 +/- 1.8 for the delayed treatment group. Both treated groups had a significantly better IS (t tests, P less than 0.001 and P less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous peritoneal dialysis in acute experimental pancreatitis in dogs. Effect of aprotinin in the dialysate medium

In 27 beagle dogs, acute necrotizing pancreatitis was induced by retrograde injection of autologous bile and trypsin into the main pancreatic duct. Animals were randomly assigned to the following treatments: group 1--(9 dogs) aprotinin 600,000 KIU/d by i.v. route; group 2--(9 dogs) peritoneal dialysis for 6 d plus 500,000 KIU/L of aprotinin in the dialysate fluid; group 3--(9 dogs) peritoneal dialysis without aprotinin in the dialysate fluid. All dogs of the group 1 died within 16 h following the induction of pancreatitis and extensive necrotizing and hemorrhagic changes were seen in the pancreatic and peripancreatic areas. Six dogs of the group 2 survived and no necrotizing changes were observed 30 or 50 d after the induction of pancreatitis. Three dogs of the group 3 survived, but slight necrotizing lesions were found at the autopsy. The survival rate was higher in dogs with peritoneal lavage (p = 0.0129) or with peritoneal lavage plus aprotinin (p less than 0.0001) than in those receiving i.v. aprotinin, indicating that the latter treatment has no beneficiary effect on the course of acute pancreatitis.

Phospholipase A2 induced diffuse alveolar damage--effect of indomethacin and dexamethasone upon morphology and plasma-histamine level

Phospholipase A2, injected as a bolus into the jugular vein of adult male Wistar rats was investigated with respect to its action upon lung morphology and blood- plasma- histamine. In comparison with the injection of saline, phospholipase A2 causes hyperemia of the lungs, sequestration of granulocytes and intraalveolar pulmonary edema; the histamine level is increased to the sixfold. Pretreatment of the animals with indomethacin diminishes the toxic effect of phospholipase A2 upon the lungs and the histamine level.

Intestinalization of pancreatic fragments in dogs: improvement in survival rate after acute segmental pancreatitis

Intestinalization, a new method of pancreatic preservation in which vascularized pancreatic fragments are placed inside a jejunal pouch, has been tested for its effectiveness in the prevention of shock and death due to segmental pancreatitis. Intestinalization of the fragment resulted in the survival of eight of nine animals (89 percent) in which recovery was uneventful, whereas animals with pancreatitis in situ or in a mobilized fragment without intestinalization had a mortality rate of 100 percent within 2 days. We conclude that intestinalization ameliorates the outcome of hemorrhagic pancreatitis in the pancreatic fragment by effectively draining toxic products. The procedure may also be useful in pancreatic transplantation since no reintervention is necessary if graft failure or rejection occurs because the pancreas is accessible by endoscopy.

Pancreatic resection versus peritoneal lavation for acute fulminant pancreatitis. A randomized prospective study

Thirty-five patients with acute fulminant (hemorrhagic) pancreatitis, verified at laparotomy, were allocated to either pancreatic resection (18 patients) or peritoneal lavation (17 patients) therapy groups. Pancreatic resection was carried out by removing the distal pancreas well cephalad to the portal vein. For peritoneal lavation, two inlet silicone catheters were inserted at laparotomy around the pancreas and an outlet catheter was inserted in the lower abdomen, and the peritoneal cavity was thereafter lavated (1000 ml/hr) with a standard peritoneal dialysis fluid for 7 to 12 days (or until death if met earlier). In other respects, the postoperative care was similar, including intravenous fluids with total parenteral nutrition until oral intake of food was resumed, prophylactic antibiotics (tobramycin and clindamycin) and stress ulcer prophylaxis (cimetidine and antacids). In the resection group, four of the 18 patients (22.2%) died, while in the lavation group eight of the 17 patients (47.1%) died. The most common cause of death was septic complications with multiple organ failure, but one patient in each group died accidentally of airway complications. There was no difference in the incidence of septic complications (sepsis and/or intra-abdominal abscesses), but the incidence and severity of pulmonary and renal complications were greater in the lavation group. However, these complications accumulated to patients who ultimately died. Also, the need for reoperation was greater in the lavation group (20 reoperations/10 patients versus 12 reoperation/eight patients). Yet, the length of overall hospital stay was equal in the two groups. Six of the 14 survivors in the resection group developed diabetes, whereas none of the nine survivors in the lavation group got this complication. The results suggest that pancreatic resection is superior to peritoneal lavation in the management of acute fulminant (hemorrhagic) pancreatitis, decreasing mortality and affording smoother postoperative course. However, these benefits are gained at the expense of higher incidence of postoperative diabetes.

Pulmonary complications in fatal acute hemorrhagic pancreatitis

Morphological changes of the lung occur frequently in fatal acute hemorrhagic pancreatitis. The pulmonary alterations are independent of mechanical ventilation and therefore not due to iatrogenic damage caused by high inspired oxygen concentrations. The histological findings are similar to those seen in the so-called shock lung syndrome. The pulmonary lesion develops progressively and three stages can be separated: early, late, and final phase. The pulmonary complications in acute hemorrhagic pancreatitis may be explained by the release of mediators such as pancreatic enzymes or free fatty acids into the blood stream. In acute hemorrhagic pancreatitis a close monitoring for shock parameters is necessary. A fall in arterial PO2 is an early indication for mechanical ventilation, including positive end-expiratory pressure.

Continuous peritoneal dialysis as treatment of acute experimental pancreatitis in the rat. II. Analysis of its beneficial effect

In acute sodium-taurocholate-induced pancreatitis in the rat, peritoneal dialysis reduced serum amylase levels and the amount of fat necrosis, but did not influence the damage to the pancreas itself. Pancreatic ascites obtained in the early course of the disease was found to have a hypotensive effect when given intraperitoneally to healthy rats. This effect vanished in the later course of acute experimental pancreatitis and was reduced by acidification of the ascites or by administration of an antihistaminic drug. Thus the beneficial effect of continuous peritoneal dialysis on survival time and mortality rate seems to be of systemic origin.

The role of peritoneal lavage in severe acute pancreatitis

Encouraged by reports of the therapeutic efficacy of peritoneal lavage in small series of five or six patients with acute pancreatitis, we have evaluated this treatment in 24 patients with "severe" pancreatitis. One hundred and three patients with "severe" pancreatitis (28% mortality) were separated from 347 with "mild" pancreatitis (0.9% mortality) by previously described early objective signs. Early treatment (Day 0-7) of "severe" pancreatitis included peritoneal lavage through catheters placed nonoperatively in 18 (Group A) and by catheters placed at laparotomy in six (Group C). Early treatment of nonlavaged patients with "severe" pancreatitis was by standard nonoperative measures in 61 (Group B) and included early operation in 18 (Group D). Lavage was continued for 48-96 hours, usually using 36-48 L/24 hours of balanced isotonic dialysate fluid, and was uncomplicated. Lavage led to striking immediate clinical improvement and no lavaged patient (Groups A and C) died during the first 10 days of treatment of pancreatitis. By contrast, 45% of deaths in nonlavaged patients (Group B and D) occurred during this early period, usually from cardiovascular or respiratory failure. Although lavage reduced mortality in subgroups of patients, ultimate overall survival was no affected (Group A, 83%; B, 84%; C, 33%; D,33%). Late peripancreatic abscesses caused most deaths in lavaged patients. These data show that peritoneal complications of severe acute pancreatitis and dramatically reduces early mortality. Lavage does not prevent the late local sequelae of peripancreatic necrosis.

The pathogenesis of pulmonary edema in acute pancreatitis

Acute pulmonary edema appeared 3 or more days after the onset of acute pancreatitis in 7 patients, an approximate incidence of 8%. The severity of pancreatitis in these patients was characterized by massive requirements for intravenous colloid and by marked hypocalcemia. In addition, at least 5 of the 7 patients had very high serum levels of triglycerides at the time of hospital admission. Hemodynamic studies during pulmonary edema showed normal central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, and pulmonary vascular resistance. Cardiac index was appropriately elevated. Respiratory treatment, consisting of endotracheal intubation and controlled ventilation with PEEP, was successful in allowing reversal of the pulmonary injury and recovery of respiratory function within 1-2 weeks in all cases. Two patients died later from pancreatic abscesses. The findings indicate that a distinct form of pulmonary injury may occur in acute pancreatitis, characterized by loss of integrity of the alveolar-capilllary membrane, leading to pulmonary edema. The mechanism of injury is not known but may be caused by circulating free fatty acids, phospholipase A, or vasoactive substances. The pulmonary membrane lesion appears to heal during the period of intensive respiratory support.