Detection, pathogenesis, and prevention of damage to human granulocytes caused by interaction with nylon wool fiber. Implications for filtration leukapheresis

Biomaterial-induced dysfunction in the capacity of rabbit alveolar macrophages to kill Staphylococcus epidermidis RP12

The effect of poly(methyl methacrylate) (PMMA), titanium alloy, and silicone discs on the capacity of rabbit alveolar macrophages (AM) to kill RP12 strain of Staphylococcus epidermidis (RP12) was studied in vitro. When freshly harvested AM were preincubated with PMMA discs for 3 h and subsequently assayed for RP12 killing, there was no change in the RP12 killing capacity of AM. However, when AM were incubated with PMMA discs for 6 or 18 h at 37 degrees C in 5% CO2, the RP12 killing capacity of AM was reduced to 15% and 4%, respectively. Preincubation of AM with titanium alloy for 6 h reduced RP12 killing capacity of AM to 30%, and to 21% in 18-h incubation. Silicone discs did not affect the RP12 killing by AM at 6 h of preincubation, but reduced RP12 killing (35%) by AM when preincubated for 18 h. Preincubation of AM with PMMA discs for 3 or 6 h did not affect the level of PMA-elicited oxidative burst of AM as measured by a luminol-enhanced chemiluminescent assay. Superoxide dismutase, which eliminated the oxidative burst of AM by 90%, did not affect the RP12 killing by AM.

Measurement of intracellular hydrogen peroxide induced by biomaterials implanted in a rodent air pouch

Biomaterials elicit an inflammatory response that is undoubtedly a factor in their healing and in the complications associated with their use. Herein, we report the modification of a rat air pouch in which we measured the production of intracellular hydrogen peroxide by inflammatory cells adherent to the surfaces of silicone elastomer (SE) and expanded polytetrafluoroethylene (ePTFE). We used the fluorescent probe dichlorofluorescein diacetate (DCFH-DA) to measure the intracellular production of hydrogen peroxide 2 and 7 days after implantation. After 2 days, host cells adherent to ePTFE produced almost 3.5 times more hydrogen peroxide than did cells adherent to SE (P < .001). By 7 days, the H2O2 production of cells adherent to ePTFE had decreased while that on cells adherent to SE was unchanged. These data indicate that the air pouch is a good alternative to other in vivo models for studies of the biological reactions induced by biomaterials.

Biomaterial-induced alterations of neutrophil superoxide production

Because periprosthetic infection remains a vexing problem for patients receiving implanted devices, we evaluated the effect of several materials on neutrophil free radical production. Human peripheral blood neutrophils were incubated with several sterile, lipopolysaccharide (LPS)-free biomaterials used in surgically implantable prosthetic devices: polyurethane, woven dacron, and velcro. Free radical formation as the superoxide (O2-) anion was evaluated by cytochrome c reduction in neutrophils that were exposed to the materials and then removed and in neutrophils allowed to remain in association with the materials. Neutrophils exposed to polyurethane or woven dacron for 30 or 60 min and then removed consistently exhibited an enhanced release of O2- after simulation via receptor engagement with formyl methionyl-leucyl-phenylalanine. Enhanced reactivity to stimulation via protein kinase C with phorbol myristate acetate, however, was not consistently observed. The cells evaluated for O2- release during continuous association with the biomaterials showed enhanced metabolic activity during short periods of association (especially with polyurethane and woven dacron). Although O2- release by neutrophils in association with these materials decreased with longer periods of incubation, it was not obliterated. These studies, therefore, show that several commonly used biomaterials activate neutrophils soon after exposure and that this activated state diminishes with prolonged exposure but nevertheless remains measurable. The diminishing level of activity with prolonged exposure, however, suggests that ultimately a depletion of reactivity may occur and may result in increased susceptibility to periprosthetic infection.

Induction of leukocyte activation by meshes surgically implanted in the peritoneal cavity

The search for surgical prosthetics that do not act to promote infection has been frustrating. However, recent experience with the implantation of polyglycolic acid mesh (PGA) used as an intestinal sling has been associated with a lack of pelvic infections. To examine the basis for these observations, 1 x 1-cm pieces of biomaterials were sewn onto the peritoneal cavity of rats. The biomaterials examined included PGA mesh, a composite mesh composed of a permanent nonabsorbable Novafil inner layer coated with a PGA outer layer, polyvinyl alcohol sponge, and silicon elastomer. Biomaterials were removed at postoperative days 1, 2, 8, and 14, and examined for bacteriostatic and bactericidal activity by standard techniques. Mesh adherent leukocytes were evaluated for their ability to oxidize dichlorofluorescein diacetate (DCFH-DA), which is fluorescent in the presence of intracellular hydrogen peroxide produced by both polymorphonuclear cells and monocytes. PGA and the composite mesh had no intrinsic bacteriostatic or bactericidal activity. However, adherent leukocytes were induced to oxidize DCFH at levels 10-fold and 5-fold, respectively, by postoperative day 14, compared with earlier time points and other biomaterials. The ability of these PGA meshes to stimulate respiratory bursts by peritoneal cells may partly be responsible for the lack of infections associated with their use.

Peritoneal leukocyte response following placement of polyglycolic acid intestinal sling in patients with rectal carcinoma

The intestinal sling procedure has been used successfully without the observance of pelvic infections. This procedure involves the implantation of polyglycolic acid (PGA) mesh to hold the bowel out of the pelvis to prevent radiation enteritis. We previously showed that PGA mesh has no intrinsic bactericidal activity. Since phagocytic leukocytes produce reactive oxygen intermediates during respiratory burst that are associated with oxygen-dependent bactericidal activity, we examined peritoneal cell types and their respiratory burst activity isolated from patients with biopsy-confirmed rectal carcinoma who underwent the intestinal sling procedure (N = 12) compared with patients who did not (N = 13). There was no significant difference in the cell types within the peritoneal cavity over the 7-day postoperative period examined. However, there was a significant increase in the ability of leukocytes isolated from mesh patients to produce hydrogen peroxide in the absence of an exogenous stimulus (P less than 0.05), as measured by flow cytometric quantitation of oxidation of the hydroperoxide-sensitive dye, 2',7'-dichlorofluorescin diacetate (DCFH-DA). Despite the higher endogenous DCFH oxidation by leukocytes from mesh patients, the cells retained the ability to oxidize DCFH following treatment with a membrane-active stimulant for respiratory burst activity, 12-O-tetradecanoyl-phorbol-13-acetate. These observations suggest that PGA mesh used for the intestinal sling procedure stimulates the respiratory burst activity of peritoneal leukocytes during the postoperative period in which bacterial proliferation and colonization occur. The stimulation of reactive oxygen intermediates involved in oxygen-dependent bactericidal activity by PGA mesh may be one of the mechanisms underlying the lack of infections observed with the use of PGA mesh in contaminated settings.

Demonstration of transient bacterobilia by foreign body implantation in feline biliary tract

The biliary tract of cats is known to be free of autochthonous bacteria above the sphincter of Oddi. In this experiment we investigated whether transient bacterobilia occurs in the biliary system under normal conditions. Polyethylene tubes and human cholesterol stones were implanted surgically into the gallbladder of cats. Sham cholecystostomy was performed as control operation. These cats were euthanized at two, six, and 12 weeks, and the implants were removed, cultured, and studied by scanning electron microscopy (SEM). Cultures and SEM also were undertaken for material scraped from the mucosal surface of the biliary tract from these animals. Colonization of bacteria on the polyethylene tubes and the gallstones was found six and 12 weeks after implantation. Adherent bacterial biofilms were demonstrated on the surfaces of these implants. This experiment showed that transient bacterobilia exists in the feline biliary tract. The foreign body implants have facilitated the adhesion of planktonic bacteria in the bile onto their surfaces and have initiated the formation of adherent biofilms within which these bacteria persisted until the system was sampled.

Effect of combinations of antioxidants on phagocyte-induced sister-chromatid exchanges

Combinations of oxygen radical scavengers and antioxidants significantly reduced the number of sister-chromatid exchanges in Chinese hamster ovary cells exposed to human phagocytes stimulated to generate oxygen radicals. When vitamin E was combined with these antioxidants, no increase in sister-chromatid exchanges was observed compared to controls.

Effects of arachidonic acid and inhibitors of arachidonic acid metabolism on phagocyte-induced sister chromatid exchanges

Stimulated human phagocytes produce toxic oxygen radicals which induce sister chromatid exchanges in cultured mammalian cells. Oxidative damage to membranes initiates lipid peroxidation chain reactions and stimulation of the arachidonic acid cascade. The products of these reactions may mediate the genetic toxicity of oxygen radicals. Arachidonic acid significantly augmented the number of sister chromatid exchanges in target cells exposed to stimulated phagocytes. This genetic damage was abrogated in radical-treated cells preincubated with inhibitors of the cyclooxygenase (indomethacin), lipoxygenase (nordihydroguaiaretic acid) or both (piroxicam) pathways.

The effect of vitamin C on oxygen radical-induced sister-chromatid exchanges

We studied the effects of vitamin C (sodium ascorbate) on the genotoxicity of oxygen radicals to tissue culture cells. Chinese hamster ovary cells (CHO cells), when exposed to an enzymatic oxygen radical generating system (xanthine oxidase plus hypoxanthine), develop increased numbers of sister-chromatid exchanges (SCEs). Inclusion of ascorbate in these incubations resulted in significant, but variable effects. In some cases, ascorbate (less than 0.1 mM) was protective and fewer SCEs were produced. In others, significant augmentation of oxygen radical-induced SCEs occurred. These experiments illustrate the complexity of the interactions of ascorbate in biologic systems and the difficulty of predicting a desirable or harmful effect.

Effects of antioxidants on oxidant-induced sister chromatid exchange formation

Stimulated human phagocytes produce sister chromatid exchanges in cultured mammalian cells by a mechanism involving oxygen metabolites. Experiments were designed to determine whether antioxidants inhibit this process. Superoxide dismutase, catalase, and hydroxyl radical scavengers (benzoate, mannitol) protected target Chinese hamster ovary cells from phagocyte-induced sister chromatid exchanges, implicating the involvement of hydroxyl radicals in this chromosomal damage. N-acetylcysteine and beta-carotene were also protective. alpha-Tocopherol (greater than 5 microM) protected target cells exposed to phagocytes but not to enzymatically generated oxidants when the vitamin was added just before the source of oxygen radicals, suggesting, as reported by others, that the principal action of tocopherol in this setting was to inhibit the release of oxidants from phagocytes. On the other hand, cultivation of target cells with supplemental tocopherol protected them from the toxic effects of the enzymatic oxidant-producing system, indicating a role for membrane-associated free radicals in the mechanism of sister chromatid exchange induction. Low concentrations of sodium selenite (0.1-1.0 microM) protected the target cells. However, higher concentrations (10 microM) of selenite had no effect on oxidant-induced sister chromatid exchange formation, and 0.1 mM selenite increased the number of exchanges. Sodium selenite concentrations of 0.1 mM also decreased the intracellular glutathione concentration of target cells during an oxidant stress, and reducing target cell glutathione concentrations with buthionine sulfoximine increased their sensitivity to oxygen-related chromosomal damage. Therefore, the potentiation of oxygen radical-induced chromosomal damage observed with high concentrations of selenite may result from a decrease in the thiol antioxidant defense systems within the cell. The findings suggest that the hydroxyl radical has an important role in the production of phagocyte-induced cytogenetic injury, membrane-derived intermediates may be involved, depletion of intracellular glutathione renders cells more susceptible to this injury, and supplementation of target cells with antioxidants can protect them from oxygen radical-generated chromosomal injury.

Pathogenesis of foreign body infection. Evidence for a local granulocyte defect

Implanted foreign bodies are highly susceptible to pyogenic infections and represent a major problem in modern medicine. In an effort to understand the pathogenesis of these infections, we studied the phagocytic function in the vicinity of a foreign body by using a recently developed guinea pig model of Teflon tissue cages subcutaneously implanted (Zimmerli, W., F.A. Waldvogel, P. Vaudaux, and U.E. Nydegger, 1982, J. Infect. Dis., 146:487-497). Polymorphonuclear leukocytes (PMN) purified from tissue cage fluid had poor bactericidal activity against a catalase-positive microorganism. When compared with blood or exudate PMN, they exhibited a significant reduction in their ability to generate superoxide in response to a particulate or a soluble stimulus (72 and 57%, respectively, P less than 0.001). Not only their total contents in myeloperoxidase, beta-glucuronidase, lysozyme, and B12 binding protein were significantly reduced (by 62, 21, 47, and 63%, respectively, P less than 0.01), but also their capability for further secretion of residual B12 binding protein upon stimulation. Ingestion rates of endotoxin-coated opsonized oil particles were reduced by 25% (P less than 0.05). In an effort to reproduce these abnormalities in vitro, fresh peritoneal exudate PMN were incubated with Teflon fibers in the presence of plasma. Interaction of PMN with the fibers led to significant increases in hexose monophosphate shunt activity and exocytosis of secondary granules (P less than 0.01). PMN eluted after such interaction showed defective bactericidal activity, oxidative metabolism, and granular enzyme content similar to those observed in tissue cage PMN. The local injection of fresh blood PMN into tissue cages at the time of, or 3 h after, inoculation with 100 microorganisms (Staphylococcus aureus Wood 46) reduced the infection rate from 50 to 56 cages to 1 of 21 (P less than 0.001) and 3 of 8 cages (P less than 0.001), respectively. These results suggest that the in vivo as well as in vitro interaction of PMN with a nonphagocytosable foreign body induces a complex PMN defect, which may be partly responsible for the high susceptibility to infection of foreign bodies.

Perturbations of granulocyte counts induced by procedural, chemical and physiological events occurring during filtration leukapheresis in rats

During filtration leukapheresis a factor(s) is produced, released or extracted into rat blood which causes a transient granulocytosis in pheresed animals and in recipients of homologous plasma from these animals. To identify which factors contribute to this granulocytosis, the procedural steps involved in filtration leukapheresis as well as a number of chemical agents which are potentially extracted from of produced by the procedure, were tested for their ability to stimulate granulocytosis. Procedural steps tested included the depth of anesthesia, effect of the anticoagulant and possible interactions of blood cells with the plastic tubing in the system (sham-pheresis). Chemical agents tested included common mediators of inflammation and proteinases released by polymorphonuclear leukocytes (PMNs), extracts of nylon fibers and Tygon tubing, nylon monomers and solvents used in the manufacture of nylon, oxidized and decomplemented plasma and lysates of PMNs or microorganisms. Our findings demonstrate that several of these agents contribute to the granulocytosis seen during filtration leukapheresis of rats.

Current view of neutrophil dysfunction: an integrated clinical perspective

Normal neutrophil function is dependent on the integration of chemotaxis, phagocytosis, degranulation and oxidative metabolism. The availability of in vitro assays for the separate quantitative evaluation of each function has permitted the definition of specific congenital and acquired neutrophil abnormalities, which are associated with defective host resistance. The appreciation of complex and often adverse effects of certain systemic diseases and drugs on neutrophil function as well as the use of new approaches to therapy suggest the importance of assessing the role of the neutrophil in states of impaired host defense.

H2O2 release from filtration leukapheresis-procured leukocytes

Filtration leukapheresis-procured leukocytes (FL-leukocytes), which were collected by the elution of filtration columns with vigorous tapping, released a certain amount of H2O2 even in the absence of any phagocytic stimuli. Furthermore, FL-leukocytes, eluted with either gentle or vigorous tapping, exhibited a marked release of H2O2 during phagocytosis. The myeloperoxidase (MPO) activity of FL-leukocytes was lower than that of leukocytes collected by the dextran sedimentation method (DS-leukocytes). The data suggest that the release of both H2O2 and MPO from FL-leukocytes may be related to adverse transfusion reactions and abnormal post-transfusion kinetics of FL-leukocytes due to their toxic effects on living cells.

Antigenic modulation and turnover in human neutrophils

Turnover of membrane constituents appears important in many biologic processes. We studied this process in neutrophils by immunologic methods. The capacity of neutrophils to recognize other neutrophils coated with antibodies against membrane antigens was used to determine the changes that occur after attachment of the antibody to the neutrophil membrane. Neutrophils were sensitized for 30 min at 22 degrees C with antibodies from three patients with antineutrophil autoantibodies. The sensitized neutrophils were recognized by normal neutrophils, which responded with an increase in glucose oxidation. If, after sensitization, the sensitized neutrophils were not immediately exposed to normal neutrophils, but instead were incubated at 37 degrees C for varying times, the capacity to elicit a recognition response decayed and was gone by 30 min. Additionally, the capacity of the cells to be resensitized by reexposure to antibody also decayed during this period. However, after further incubation at 37 degrees C, the neutrophils recovered the capacity to become sensitized; and this recovery was not inhibited by the addition of cycloheximide. Control incubations with normal immunoglobulin (Ig)G did not elicit a recognition response. The decay in recognition response was temperature dependent. Direct immunofluorescent studies with fluorescein-conjugated antineutrophil IgG revealed that the antibodies were cleared by aggregation and endocytosis. We conclude that: (a) neutrophils clear antibody from the cell surface by a temperature-dependent mechanism; (b) antigenicity is cleared concomitantly; (c) the mechanism of clearance involves internalization; and (d) with time, antigenicity reappears on the cell surface.

Release of arachidonic acid from human lymphocytes in response to mitogenic lectins

After exposure to mitogenic lectins in vitro, human mononuclear cells (95% lymphocytes) that had been prelabeled with [14C]arachidonic acid rapidly released a portion of their radioactivity in the medium. Most of the released radioactivity was demonstrated to be free arachidonic acid. Although other sources are not excluded, the most important source of cell-bound radioactivity in the release reaction appeared to be phosphatidylinositol, suggesting that at least part of the response is occurring through an increase in phospholipase A2 activity. By gas liquid chromatography, other fatty acids were also shown to be released, but there was considerable selectivity in the response for arachidonic acid. The response was dependent on the availability of free Ca++ in the medium and was enhanced by serum proteins and unlabeled arachidonic acid. Most of the response appeared to be from the the lymphocytes themselves rather than from contaminating cells. The rapid generation of free arachidonic acid in response to mitogenic lectins suggests a possible role for arachidonic acid metabolites in the activation process.

Chemotactic deactivation of human neutrophils: possible relationship to stimulation of oxidative metabolism

Neutrophils preexposed to high concentrations of activated complement or synthetic N-formyl methionyl peptides are inhibited in their subsequent spontaneous and chemotactic migratory responses. We have considered the possibility that a part of this nonspecific loss of migratory function may be attributable to the interaction of the leukocytes with reactive forms of oxygen deriving from the cytotaxin-induced burst of oxidative metabolic activity. For these studies we have assessed the effect of preexposure of neutrophils from patients with chronic granulomatous disease to cytotaxins on their subsequent migratory responses. We find that these responses are not altered by preexposure to either cytotaxin. Thus, there appears to be a functional relationship between deactivation and the ability of the normal neutrophil to undergo a cytotaxin-induced respiratory burst.

Chemotactic deactivation of human neutrophils: evidence for nonspecific and specific components

Human polymorphonuclear neutrophils have been preexposed to activated complement as zymosan-activated serum (ZAS) or to the chemotactic oligopeptide N-formyl methionylphenylalanine (F-Met-Phe). Spontaneous migration and chemotactic responses toward the deactivating and other cytotaxins were monitored after washing and resuspension of cells in cytotaxin-free medium. Two patterns of deactivation were observed. Preexposure of the leukocytes to high doses of ZAS or F-Met-Phe decreased all subsequent migratory responses. Preexposure of the leukocytes to lower doses of ZAS or F-Met-Phe decreased only a subsequent chemotactic response to the deactivating cytotaxin. These results suggest two mechanisms, or components, of chemotactic deactivation.

Granulocyte transfusions for the prevention of infection in patients receiving bone-marrow transplants

Prophylaxis by granulocyte transfusions against infection associated with granulocytopenia was studied in 69 patients receiving bone-marrow transplants for the therapy of hematologic neoplasia or aplastic anemia. Patients were randomized to receive or not to receive granulocyte transfusions when their circulating granulocyte levels fell to less than 200 per cubic millimeter during the period between transplantation and the development of graft function. During the first 21 posttransplant days, there were two local infections and no septicemias in 29 transfused patients. Seven local infections and 10 septicemias developed among the 40 controls. This protection was afforded by granulocytes collected by reversible leukoadhesion as well as by cells collected by continuous-flow centrifugation.