Perioperative fluctuation in plasma levels of granulocyte elastase and alpha-1-antitrypsin: the influence of the severity of surgical intervention and their effect on the respiratory index

Relationship between plasma neutrophil elastase and respiratory index of patients who had undergone cardiac surgery with cardiopulmonary bypass

To evaluate the effects of cardiopulmonary bypass (CPB) on the release of polymorphonuclear leukocyte elastase (PMN-E) and postoperative pulmonary function, the perioperative plasma levels of PMN-E in α1-antitrypsin complex (EAC) and hydrogen peroxide concentration in the expired breath were measured in eight patients who underwent cardiac surgery with CPB, and the relationship between EAC levels and the respiratory index (RI) was studied. Although PMN, EAC, and the ratio of EAC to neutrophil (E/N) were elevated significantly after surgery, alveolar-arterial oxygen difference (A-aDO2) and respiratory index (A-aDO2/PaO2) did not change when compared with those of the preoperative period. Hydrogen peroxide concentration in the expired breath also did not change (below 2.5 μmol·l(-1)) during the perioperative period. These results suggest that the elevation of EAC immediately after cardiac surgery using CPB, which lasted less than 2h, was not a cause of postoperative pulmonary disorder. However, there was a significant positive correlation between E/N ratio and respiratory index (r=0.67,P<0.01). Thus excessive release of PMN-E during CPB may be implicated in the etiology of postoperative respiratory dysfunction.

Protease activation during surgical stress in the rat small intestine

BACKGROUND

Surgical stress affects intestinal permeability and our earlier study using a rat model indicated that oxidative stress plays an important role in this process. Proteases are important mediators of cellular damage and are known to be activated in oxidative stress. This study looked at protease activity in enterocytes after surgical stress.

METHODS

Surgical stress was induced by opening the abdominal wall and handling the intestine as done during laparotomy, in normal and xanthine oxidase-deficient rats. Enterocytes at various stages of differentiation were isolated and protease activity and protection offered by xanthine oxidase inhibitors were determined. Mitochondria and cytosol were prepared from total isolated enterocytes at different periods after surgical stress and protease activation was studied.

RESULTS

Surgical stress induced activation of proteases in both the villus and crypt cells. Protease activation is seen in both mitochondria and cytosol, and similar to the other alterations in mucosal cells, protease activation was maximum 60 min after stress, returning to normal by 24 h. Thiol compounds modulate protease activity in both mitochondria and cytosol and the activation is not seen in xanthine oxidase-deficient animals.

CONCLUSIONS

Surgical stress induces activation of proteases in villus and crypt cells of the small intestine. Both mitochondrial and cytosolic proteases are activated and free radicals generated by xanthine oxidase may mediate protease activation after surgical stress in the intestine.

Surgical stress and the development of complications in relation to polymorphonuclear leukocyte elastase (PMNE) levels

This study was conducted to examine the effects of surgical stress on changes in polymorphonuclear leukocyte elastase (PMNE) levels, and to evaluate the relationship of these changes to the development of postoperative complication. A total of 69 patients who underwent alimentary surgery were subsequently divided into three groups: a complicated group, comprised of 25 patients; an uncomplicated group with a high blood loss (H) of more than 1000 ml, comprised of 18 patients; and an uncomplicated group with a low blood loss (L) of less than 1000 ml, comprised of 26 patients. The changes in the levels of PMNE, fibronectin (FN), and antithrombin III (AT III) were compared among these three groups. In the uncomplicated H and L groups the PMNE levels rose significantly on postoperative day (POD) 1. On POD 3, high levels of PMNE were still evident in the uncomplicated H group, but a decline was observed in the uncomplicated L group. From POD 7 onwards the levels decreased to the preoperative values in both uncomplicated groups; however, the complicated group continued to show high levels even on POD 14. Significantly decreased FN levels were observed for the first 3 PODs in each group. The uncomplicated H and L groups regained their preoperative levels on PODs 7 and 14, respectively, but no recovery was found in the complicated group. The AT III levels showed similar changes to the FN levels in all groups. These findings indicate that monitoring the PMNE levels could be a useful index for the early detection of postoperative complications following alimentary surgery.

Serum elastase and alpha-1-antitrypsin levels in patients with ruptured and unruptured cerebral aneurysms

Despite advances in surgical treatment and postoperative care, subarachnoid hemorrhage from ruptured cerebral aneurysms remains a devastating event. Excellent surgical results in treating unruptured aneurysms suggest the utility of screening tests to identify high-risk individuals. Unfortunately, none of the known risk factors for subarachnoid hemorrhage correlates strongly enough with the illness to warrant widespread screening for occult aneurysms. Other disease entities suggest that protease-antiprotease imbalances contribute to somatic vessel wall degradation and aneurysm formation. Detection of similar imbalances in selected patients may identify a predisposition to cerebral aneurysm formation. Serum concentrations of elastase and alpha-1-antitrypsin (AAT), important proteolytic and antiproteolytic enzymes, were measured in a series of 19 patients with unruptured aneurysms, 41 patients with ruptured aneurysms, and 27 age-matched operative and nonoperative controls. The elastase:AAT ratio was nearly twice as high in patients with unruptured aneurysms as in operative controls (0.527 +/- 0.1 versus 0.285 +/- 0.06; P < 0.04). Elastase:AAT ratios in patients with ruptured aneurysms (subarachnoid hemorrhage < 48 h) were roughly twice those of controls (0.582 +/- 0.095; P < 0.01). There was no statistical difference between elastase:AAT ratios for patients with ruptured and unruptured aneurysms. Likewise, elastase-AAT values for operative controls and nonoperative volunteers were not significantly different. Differences in serum elastase:AAT ratios between patients with aneurysms and controls reflected differences in elastase concentration (99 +/- 56 micrograms/ml versus 67 +/- 56 micrograms/ml; P < 0.03), not in AAT levels (147 +/- 56 micrograms/ml versus 141 +/- 56 micrograms/ml; P < 0.72).(ABSTRACT TRUNCATED AT 250 WORDS)