Impaired neutrophil function during anesthesia and surgery is due to serum factors

Phagocytosis--the mighty weapon of the silent warriors

Professional phagocytes, comprising polymorphonuclear neutrophils and monocyte/macrophage cells, play an important role in the host defense. Any defect in their function exposes the organism to microbial intruders terminating in fatal diseases. The functional responses of the phagocytes to bacterial and fungal infections include chemotaxis, actin assembly, migration, adhesion, aggregation, phagocytosis, degranulation, and reactive oxygen species production. Superoxide generation by phagocytic NADPH oxidase is an imperative step toward bacterial killing. Phagocytes participate in inflammatory reactions and exert tumoricidal activity. They are supported by serum factors such as immunoglobulins, cytokines, complement, the acute phase reactant C-reactive protein, production of antibacterial proteins, and others. In addition to their principal task to eliminate bacteria, they are engaged in removing damaged, senescent, and apoptotic cells. Engulfed cell debris, large particles such as latex beads, fat, and oil droplets, are examples of phagocytic activity illustrated in the present review with transmission and scanning electron microscope micrographs. Numerous factors, such as diseases and stressful conditions, affect the engulfing activity of the professional phagocytes. Our experience regarding the impaired phagocytic capacity of cells in patients with diabetes and chronic renal failure is discussed. The results obtained in our laboratory from experiments detecting the effect of strenuous physical exercise, hypothermia, fasting, and abdominal photon irradiation on the phagocytic capacity of human polymorphonuclear neutrophils and rat peritoneal macrophages are hereby summarized and the reports on those subjects in the recent literature are reviewed. A variety of assays are applied for quantifying phagocytosis. Flow cytometry based on incubation of phagocytic cells with fluorescent conjugated particles and measuring the amount of fluorescence as an indicator of the engulfing capacity of the cells is a useful method. A direct visualization of the ingested particles using light or electron microscopy is a valuable tool for estimation of phagocytic function. In our hands, the use of semithin sections of embedded phagocytes following their incubation with latex particles provided satisfactory results for measuring the total number of phagocytic cells, as well as the internalizing capacity of each individual cell. Microbiological assays, the nitroblue tetrazolium test, quantitation of antibody- and antigen-mediated phagocytosis, as well as methods reviewed in detail in other reports are additional applications for determination of this intricate process.

Monocyte and neutrophil activity after minor surgical stress

BACKGROUND/PURPOSE

Surgical stress produces changes in the immune status of patients. In adults, major surgery causes immunosuppression, whereas minor operations stimulate immune responses. In children, the immunologic response to surgery has not been elucidated completely. The authors investigated the effects of minor surgery on immune response by analyzing neutrophil and monocyte phagocytosis and oxidative burst activity.

METHODS

Sixteen children undergoing elective minor surgery were enrolled. Blood samples were collected before the operation (at time of induction of anesthesia), at the end of operation, and 72 hours after surgery. Neutrophil and monocyte phagocytosis and oxidative burst activity were studied using a flow cytometric method.

RESULTS

Phagocytosis and oxidative burst increased significantly at the end of the operation, both in neutrophils (7.4% and 14.3%, respectively) and monocytes (11.6% and 27%, respectively). The increase was only significant for monocytes (17.5%) 72 hours after surgery. White cell count did not show any significant changes. There was no significant correlation between phagocytosis, oxidative burst activity, and white cell count or neutrophil and monocyte count.

CONCLUSIONS

This study shows that minor surgery in children induces immune activation by increasing neutrophil and monocyte phagocytosis and oxidative burst activity. Further studies are required to understand the molecular basis of these findings.

An improved clinically relevant sepsis model in the conscious rat

OBJECTIVE

To develop an improved small animal experimental paradigm that more closely mimics human sepsis.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

Medical school research laboratory.

SUBJECTS

Male Sprague-Dawley rats (280-320 g).

INTERVENTIONS

We monitored the hemodynamic, hematologic, and biochemical consequences of abdominal sepsis produced by intraperitoneal implantation of a fibrin clot containing Escherichia coli in conscious, antibiotic-treated, rats.

MEASUREMENTS AND MAIN RESULTS

Similar to human sepsis, the implanted, infected clot (LD50 = 5-7 x 10(8) colony forming units/mL, n = 6) elevated cardiac index (>7% vs. sterile clot, p < .05, at 4 hrs), whereas mean arterial pressure and heart rate remained unaffected. The total peripheral resistance index and stroke volume index tended to decrease and increase, respectively. In contrast, an intravenous bolus injection of endotoxin (LD50 of E. coli lipopolysaccharide = 5.6 mg/kg, n = 7), the most commonly used sepsis model, induced profound hypodynamic responses manifested by a 27% decrease (vs. endotoxin vehicle, p < .01) in cardiac index, a 28% increase in the total peripheral resistance index (p < .01), and a 33% decrease in the stroke volume index (P < .01). The infectious peritonitis model also displayed dose-dependent thrombocytopenia (<61%, p < .05), leukopenia (<60%, p < .05), and mortality rate (50% at 5-7 x 10(8) colony forming units/mL, p < .05) with a minimally elevated serum tumor necrosis factor-alpha level (145 vs. 12 +/- 6 pg/mL in controls, p < .05).

CONCLUSION

This rodent model of antibiotic-treated, intra-abdominal infection features key characteristics of clinical sepsis. Although the hyperdynamic response observed in septic patients undergoing resuscitation was not clearly elicited, this paradigm better mimics clinical sepsis compared with the commonly used endotoxin model. Thus, utilization of this paradigm may provide additional opportunities to explore mechanisms of sepsis and to examine novel therapeutics.

Cell-mediated immune response is better preserved by laparoscopy than laparotomy

BACKGROUND

This study compares the effects of carbon dioxide pneumoperitoneum versus laparotomy on cellular-mediated immune response in a murine model.

METHODS

Sixty-eight female C3H/He mice were sensitized to keyhole limpet hemocyanin (KLH) and to a mouse mammary carcinoma cell line (MC2) before surgery. Animals were randomized into 4 groups: group I, anesthesia (control); group II, pneumoperitoneum with carbon dioxide; group III, extraperitoneal wound; group IV, laparotomy. All animals were challenged subsequently with KLH and MC2 tumor cells. Delayed-type hypersensitivity skin reaction (DTH) to KLH was measured on postoperative days (PODs) 1, 2, 4, and 5. Tumor growth was assessed weekly as an indicator of postoperative cellular immune response.

RESULTS

Compared with preoperative values, postoperative DTH skin reactions were significantly less for all PODs in groups III and IV (P < .05), on POD 1 and 4 in group II (P < .05) and POD 4 for group I (P < .05). Group IV showed significantly fewer DTH skin reactions for all PODs compared with groups I and II (P < .05) and all PODs except on day 2 compared with group III (P < .05). Tumor growth was significantly increased at postoperative week 2 (n = 3/17 mice) and 3 (n = 4/17 mice) in group IV, when compared with groups I and II (P < .05).

CONCLUSIONS

Cellular immunity is preserved after carbon dioxide pneumoperitoneum compared with extraperitoneal incisions and laparotomy as measured by DTH and the ability to reject an immunogenictumor.

IgE levels in surgery: effect of ranitidine and prednisolone

BACKGROUND

Immunoglobulin E (IgE) is important in allergic reactions and in host defense against parasites. IgE may also participate in the acute-phase response to physical stress. This study aimed to determine whether major abdominal surgery induced increased serum IgE levels, and whether treatment with ranitidine or prednisolone influenced the IgE response to surgery.

METHODS

For assessment of the IgE response to surgery and the effect of ranitidine, 24 patients scheduled for major abdominal surgery were randomized to receive either perioperative treatment with ranitidine or no treatment. To evaluate the effect of glucocorticoids, 24 patients undergoing major elective abdominal surgery were randomized to receive preoperative treatment with either prednisolone or placebo. IgE levels were determined in serum samples drawn pre- and postoperatively.

RESULTS

In the ranitidine study, both the control group and the ranitidine-treated group displayed a postoperative increase (P<0.001) of serum IgE. In the prednisolone study, a postoperative increase (P<0.05) of serum IgE was detected in the placebo group. No significant increase was found in the prednisolone-treated group.

CONCLUSIONS

Major abdominal surgery induces an increase of serum IgE. This increase can be prevented by preoperative treatment with prednisolone, but not with ranitidine.

Effect of sodium thiopentone anesthesia on the phagocytic activity of rat peritoneal macrophages

To elucidate the effect of sodium thiopentone anesthesia on the function of phagocytic cells, albino rats were anesthetized with 60 mg/kg. of sodium thiopentone. After 90 min., peritoneal macrophages were harvested and their capacity for superoxide anion generation was detected. Following anesthesia for 90 min. latex particles were injected intraperitoneally, and after additional 30 min. the macrophages were derived, embedded in agar and the number of cells engaged in phagocytosis, as well as the number of latex particles engulfed by each individual cell were counted in semi-thick sections. Macrophages of anesthetized animals showed a statistically significant decrease of both superoxide anion generation and mean number of phagocytic cells, and engulfed fewer particles than those of the controls. Similar results were obtained following incubation of the cells with sodium thiopentone in vitro. The serum corticosterone level in anesthetized rats was significantly higher than that of the control animals. The results indicate that impaired phagocytosis following anesthesia induced by sodium thiopentone, in addition to alterations of the immune system caused by surgical trauma, may be one of the reasons for increased susceptibility to infections of surgical patients during the postoperative period.

Immune response: effects of operative stress in a pediatric model

PURPOSE

The purpose of this study is to delineate the effect of different operative procedures on the cell-mediated immune response in a pediatric animal model using the delayed type hypersensitivity (DTH) skin test.

METHODS

Sprague Dawley rats (1 week old) were sensitized against keyhole limpet hemocyanin (KLH). Animals were challenged 2 weeks later by an intradermal injection of KLH (0.3 mg) in sterile saline. Rats with positive DTH skin reactions at 24 and 48 hours after challenge (baseline) were divided randomly into five groups (n = 10 each): group I, unmanipulated control; group II, anesthesia; group III, anesthesia and midline extraperitoneal incision; Group IV, anesthesia and laparoscopy (pneumoperitoneum with carbon dioxide); Group V, anesthesia and midline laparotomy. Before each procedure (day 0) and on postoperative days 3 and 6, animals were again challenged intradermally with KLH (0.3 mg). DTH skin reaction was evaluated 24 and 48 hours later.

RESULTS

A statistically significant difference (P < .05) in DTH skin reaction at 24 and 48 hours was observed between postoperative days 1 to 5 in the extraperitoneal and laparotomy groups with respect to baseline and the control group. Statistically significant differences were found in postoperative days 1, 4, and 5 between laparoscopy and laparotomy. The laparoscopy group showed a statistically significant decrease in DTH skin induration on postoperative day 2 when compared with the control group. At postoperative day 7 and 8 there was no statistical difference in DTH skin response comparing baseline values or between groups.

CONCLUSIONS

These results suggest that in a pediatric animal model, abdominal surgical procedures accompanied by extensive tissue dissection produce a cellular immunosuppression, lasting up to 7 days, which is not observed in less invasive procedures. Observations concerning lesser immunosuppressive effects of laparoscopy when compared with laparotomy in adult models, as previously described by our laboratory, were also found in this pediatric model.

Effect of major surgery on neutrophil chemotaxis and actin polymerization in neonates and children

The authors have examined the effect of major surgery in neonates and older children on neutrophil (PMN) chemotaxis and on actin polymerization, an essential early step in PMN movement. Isolated PMNs from the following subjects were studied: healthy adult volunteers (n = 28), healthy newborns (n = 21), newborns undergoing major surgery (n = 7), and older infants and children undergoing major surgery (n = 14). Chemotaxis was measured by a micropore filter assay, and actin polymerization was measured by flow cytometry. Blood samples from surgical patients were obtained preoperatively, hourly during the procedure, immediately postoperatively, and 48 hours after surgery. Mean preoperative newborn PMN chemotaxis was similar to that of healthy newborn PMN, and mean preoperative PMN chemotaxis in children was similar to that of healthy adults. There were no significant alterations in PMN chemotaxis during or after major surgery in neonates or children. Peak PMN actin polymerization, after stimulation with formyl methionyl leucyl phenylalanine (FMLP) (10 nm), was significantly diminished in healthy neonates compared with adults (P < .005). Preoperative surgical neonates had similar peak PMN actin polymerization levels to those of healthy newborns, and older preoperative children had similar levels to adults. PMN actin polymerization did not significantly change during or after major surgery. Despite reductions in PMN chemotaxis and actin polymerization in healthy neonates, there is no further impairment of these PMN functions during or after major surgery. Our data suggest that PMN chemotactic function is resistant to the stress of uncomplicated major surgery in neonates and children.

Spinal anaesthesia but not general anaesthesia enhances neutrophil biocidal activity in hip arthroplasty patients

The purpose of this study was to compare neutrophil cidal activity during general or spinal anaesthesia. Assays were performed on neutrophils extracted from the blood of patients after surgery had been under way for one hour. First, the ability of the neutrophils to kill a standard laboratory strain of S. aureus was examined. Neutrophils extracted from the blood during surgery in the spinal anaesthetic group and incubated with the staphylococci for one hour killed twice as many bacteria than those from two groups of patients that received halothane or isoflurane general anaesthesia (P < 0.05). This effect persisted, to a lesser extent, in the spinal group neutrophils after two hours of incubation with the bacteria. Second, neutrophils from patients under the same conditions of surgery and anaesthesia were tested to examine the effect of the different anaesthetic techniques on neutrophil biocidal mechanisms. Neutrophils extracted during surgery in the spinal group released more superoxide in response to phorbol-12-myristate-13-acetate (PMA) than those from both groups of patients that received general anaesthesia (P < 0.05). It is concluded that there is an increased state of reactivity of the neutrophil cell membrane NADPH oxidase system in patients receiving spinal anaesthesia than in patients receiving general anaesthesia.

[Comparative study of immunologic consequences of autotransfusion and homologous transfusion in lung cancer surgery]

A study was carried out to determine the effects of transfusion with either autologous or homologous blood in 35 patients with lung cancer undergoing lung surgery. The patients were randomly allocated to two groups, "allo" receiving homologous blood (n = 10), and "auto" receiving autologous blood only (n = 13). A third control group included the patients (n = 12) who had not required any blood. In patients of "auto" group, two blood removals of 7 ml.kg-1 each were performed, provided their haemoglobin concentration was over 110 g.l-1 and their haematocrit over 34%. The following parameters were studied at t-1 (the day of inclusion), t0 (just before surgery and transfusion), t1 (one week after surgery), and t2 (one month later): haematocrit and haemoglobin concentration; IgG, IgA and IgM concentrations; polymorphonuclear and neutrophil leucocyte and lymphocyte numbers, lymphocyte subpopulations (CD4/CD8), activated natural killers (NK), polymorphonuclear leukocyte chemotaxis and chemoluminescence. Anaesthesia and surgery initiated initiated an early decrease in immunity in all three groups. The immune profile, and its time course in patients who received autologous blood only was similar to that of those who were not transfused at all. On the other hand, homologous blood transfusion seems to modify the recipient's non specific immune system. In group "allo", a decrease occurred in the number of auxiliary lymphocytes CD4, an increase in suppressor lymphocyte numbers CD8, with an increase in the CD4/CD8 ratio, and no increase in NK activity. These data suggest that autologous transfusion is well tolerated in cancer patients undergoing surgery.

Photon emission of phagocytes in relation to stress and disease

Phagocytes, the first-line cells of the body's defence mechanisms against invading pathogens, kill microorganisms by means of lysosomal degradative enzymes and highly toxic reactive oxygen intermediates. The reactive oxygen compounds are produced, in a process called the 'respiratory burst', by the NADPH oxidase complex in plasma membranes, and by myeloperoxidase in phagolysosomes after degranulation. These processes generate electronically excited states which, on relaxation, emit photons, giving rise to phagocyte chemiluminescence (CL). This paper describes the conditions for the measurement of CL, and reviews the activity of phagocytes from individuals undergoing stress or disease. The capability of phagocytes to emit photons reflects remarkably well the pathophysiological state of the host. In many cases even the magnitude of the stress, the presence of a pathogen in the body, or the activity of the disease can be estimated. Physiological changes, e.g. in the reproductive cycle, can also be predicted.

Neutrophils from patients undergoing hip surgery exhibit enhanced movement under spinal anaesthesia compared with general anaesthesia

The purpose of this research was to investigate whether the effects of regional anaesthesia on neutrophil migration differ from those due to general anaesthesia during major orthopaedic surgery in human patients. Eighteen patients underwent spinal or general anaesthesia (halothane or isoflurane) for surgery (six patients in each group). Blood samples were taken prior to induction of anaesthesia and after surgery was in progress for one hour. The movement of isolated neutrophils was measured in both samples in the chemotactic chamber toward lipopolysaccharide activated pooled serum. In addition plasma concentrations of catecholamines were determined in the blood samples. Neutrophils extracted from peripheral blood during spinal anaesthesia and surgery moved further towards a complement-derived attractant than neutrophils obtained from patients undergoing surgery under general anaesthesia with halothane or isoflurane and surgery (156.4 +/- 7.6 microns vs 114.3 +/- 6.1 microns or 119 +/- 8.4 microns respectively, P < 0.05). Increased concentrations of adrenaline were present in both general anaesthetic groups whereas the spinal group had lower concentrations than those prior to anaesthesia and surgery. It is considered unlikely that these differences in neutrophil reactivity are due to the direct effects of anaesthetic agents employed. The effects are likely to be the result of differing effects of spinal anaesthesia on the stress response or immunological mediators.

Immunosuppression in Trauma Patients

An immunosuppressed state develops following traumatic injury, which makes patients more prone to develop infection. A variety of disturbances accompany injury that affect both specific and nonspecific components of host defense. Many clinical studies have attempted to evaluate the many deficits that follow injury and place the patient at a higher risk for infection. Several components of host defense are affected simultaneously and include (1) cellular changes (decreased activation of T-lymphocyte subsets with decreased helper cells, increased suppressor T-cell function, increased but abnormal activity of macrophages, activation of polymorphonuclear leukocytes with depressed chemotaxis and killing); (2) depressed nonspecific and specific serum immunity (e.g., depressed fibronectin and immunoglobulin levels); (3) the presence of altered cytokine levels (interleukin-1 [IL-1], IL-2, IL-6, tumor necrosis factor) levels; (4) ongoing serum proteolytic activity; and (5) the generation of serum suppressive peptides. An in-depth understanding of the deficits that occur following injury in host defense will provide the basis for therapeutic intervention.

Impaired polymorphonuclear leucocyte function in patients undergoing hepatectomy: adenylate energy charge and superoxide anion production in relation to hepatic mitochondrial redox state

Patients undergoing hepatectomy have an increased susceptibility to infection. We therefore studied the energy metabolism of the polymorphonuclear leucocyte (PMN), focusing on energy charge and function, especially superoxide anion (O2-) generation, in relation to the hepatic mitochondrial redox state. By labelling the PMN adenine nucleotide pool with radioactive adenine and by superoxide dismutase-inhibitable reduction of ferricytochrome c, the energy charge and O2- production was measured in 18 patients with hepatoma (non-cirrhotic, seven; cirrhotic, 11) undergoing hepatectomy. Their arterial ketone body ratios (KBRs), reflecting the hepatic mitochondrial redox potential, were above 0.7 before operation. After surgery, the 18 patients were divided into two groups: group A, KBR greater than 0.7, n = 10; and group B, KBR less than 0.7, n = 8. The energy charge and O2- release in group B decreased significantly from preoperative values (P less than 0.001 and P less than 0.01 respectively) and when compared with group A (P less than 0.05 and P less than 0.01 respectively). These results suggest that impaired hepatic energy metabolism (KBR less than 0.7) in hepatectomized patients leads to impaired energy charge and O2- production in the PMNs.

The capacity of serum to support neutrophil phagocytosis is a vital host defense mechanism in severely injured patients

The opsonic capacity of patient serum was studied in 43 trauma patients of whom 13 recovered uneventfully, 21 developed major infection, and nine died, mostly of infection. Blood samples were taken within 24 hours of injury. Fifteen patients were studied serially of whom 14 developed severe infection and/or died. Opsonic capacity was determined by flow cytometry and measured as the ability of normal neutrophils to phagocytose killed bacteria previously incubated with patient serum. The most dilute sera reflected changes for better and worse most clearly. On initial assessment, those who died of sepsis showed a 61% mean fluorescent intensity (MFI), which was significantly lower than the 99% MFI for those who survived infection (p less than 0.01) and the 78% MFI of those who developed no infection (p less than 0.05). Serial samples demonstrated a super serum response in four of seven patients surviving major sepsis but in none of the seven who died of infection.