Intestinal epithelial cells modulate antigen-presenting cell responses to bacterial DNA.

Intestinal epithelial cells and antigen-presenting cells orchestrate mucosal innate immunity. This study investigated the role of bacterial DNA in modulating epithelial and bone marrow-derived antigen-presenting cells (BM-APCs) and subsequent T-lymphocyte responses. Murine MODE-K epithelial cells and BM-APCs were treated with DNA from either Bifidobacterium breve or Salmonella enterica serovar Dublin directly and under coculture conditions with CD4(+) T cells. Apical stimulation of MODE-K cells with S. Dublin DNA enhanced secretion of cytokines from underlying BM-APCs and induced interleukin-17 (IL-17) and gamma interferon (IFN-γ) secretion from CD4(+) T cells. Bacterial DNA isolated from either strain induced maturation and increased cytokine secretion from BM-APCs. Conditioned medium from S. Dublin-treated MODE-K cells elicited an increase in cytokine secretion similar to that seen for S. Dublin DNA. Treatment of conditioned medium from MODE-K cells with RNase and protease prevented the S. Dublin-induced increased cytokine secretion. Oral feeding of mice with B. breve DNA resulted in enhanced levels of colonic IL-10 and transforming growth factor ß (TGFß) compared with what was seen for mice treated with S. Dublin DNA. In contrast, feeding mice with S. Dublin DNA increased levels of colonic IL-17 and IL-12p70. T cells from S. Dublin DNA-treated mice secreted high levels of IL-12 and IFN-γ compared to controls and B. breve DNA-treated mice. These results demonstrate that intestinal epithelial cells are able to modulate subsequent antigen-presenting and T-cell responses to bacterial DNA with pathogenic but not commensal bacterial DNA inducing effector CD4(+) T lymphocytes.

Peritoneal repair and post-surgical adhesion formation.

It was shown in 1919 that peritoneal healing differs from that of skin. When a defect is made in the parietal peritoneum the entire surface becomes epithelialized simultaneously and not gradually from the borders as in epidermalization of skin wounds. While multiplication and migration of mesothelial cells from the margin of the wound may play a small part in the regenerative process, it cannot play a major role, since new mesothelium develops in the centre of a large wound at the same time as it develops in the centre of a smaller one. Development of intraperitoneal adhesions is a dynamic process whereby surgically traumatized tissues in apposition bind through fibrin bridges which become organized by wound repair cells, often supporting a rich vascular supply as well as neuronal elements.

Reactivation of coagulation after stopping infusions of recombinant hirudin and unfractionated heparin in unstable angina and myocardial infarction without ST elevation: results of a randomized trial. OASIS Pilot Study Investigators. Organization to Assess Strategies for Ischemic++ Syndromes.

AIMS: To compare effects of heparin and hirudin on biochemical markers of coagulation. METHODS AND RESULTS: Patients (n=395) with unstable angina or myocardial infarction without ST elevation were randomized to a 72-h infusion of one of three regimens: unfractionated heparin (bolus of 5000 IU followed by an infusion of 1200 IU. h(-1)), low-dose hirudin (HBW 023; 0.2 mg. kg(-1)bolus followed by 0.10 mg. kg(-1). h(-1)) or medium-dose hirudin (0.4 mg. kg(-1)bolus followed by 0.15 mg. kg(-1). h(-1)). Infusions were adjusted to maintain an activated partial thromboplastin time of between 60-100 s. Activated partial thromboplastin time, prothrombin fragment 1.2 (F1.2), thrombin antithrombin III complex and D-dimer were measured before, during and after the infusion. Median activated partial thromboplastin time was similar in the two groups early on, but was significantly lower in the heparin group than in the combined hirudin group 48 h after starting the infusion (53 s and 75 s, respectively;P<0.001), and 6 h after stopping (31 s and 46 s, respectively;P<0.001). Median F1.2 levels were not significantly different between the groups during the infusion. Median thrombin antithrombin III levels in the heparin and hirudin groups were 2.8 microg. l(-1)and 2.3 microg. l(-1), respectively, at 6 h (P<0.001), and 3.0 microg. l(-1)and 2.3 microg. l(-1), respectively, at 48 h (P<0.001). Median D-dimer levels were 320 ng. ml(-1)and 260 ng. ml(-1)48 h after starting the infusion in the heparin and hirudin groups, respectively (P<0.001), and 415 ng. ml(-1)and 280 ng. ml(-1), respectively (P<0.001) 6 h after stopping. D-dimer levels were significantly elevated above baseline values in both groups 24-48 h after stopping the infusions. CONCLUSIONS: The greater reduction of thrombin antithrombin III and D-dimer during the hirudin infusion supports the hypothesis that hirudin is a more potent antithrombin agent than heparin. Increased D-dimer levels after stopping heparin or hirudin suggest that there is an ongoing pro-coagulant state. These results point to the greater efficacy of hirudin in preventing early clinical events (death, myocardial infarction and refractory ischaemia) compared with heparin that have been observed in large randomized trials. Persistent activation of coagulation afterstopping infusions in our study suggests that a longer course of antithrombotic treatment may be needed to pacify the thrombus.

Reduction of adhesion formation by intraperitoneal administration of Arg-Gly-Asp-containing peptides.

OBJECTIVE: To evaluate the ability of a variety of peptides containing the Arg-Gly-Asp (RGD) sequence to reduce the formation of intraperitoneal adhesions in a rabbit model. DESIGN: Prospective, randomized, double-blinded study. SETTING: University-based laboratory. ANIMAL(S): New Zealand white rabbits. INTERVENTION(S): Administration of RGD-containing peptides. MAIN OUTCOME MEASURE(S): Reduction of adhesion information. RESULT(S): In initial studies, two RGD-containing peptides (3 or a 10 amino acid peptides) were administered via Alzet miniosmotic pump to the site of injury. Administration of either of these peptides significantly reduced adhesion formation, but the larger peptide was more efficacious and reduced variability in the response. Further studies then were conducted with RGD-containing peptides five to six amino acids in length. Administration of these peptides also significantly reduced adhesion formation in a standard rabbit model. Administration of three of these peptides in a viscous vehicle at the end of surgery was also effective in reducing adhesion formation. CONCLUSION(S): The most effective combination tested was RGD-containing peptide Gly-dser-Arg-Gly-Asp-Ser-Pro in a viscous, cremophor-containing vehicle. These studies demonstrate that administration of an RGD-containing peptide was effective in reducing adhesion formation in this model.

Reduction of adhesion formation in rabbits by intraperitoneal administration of lazaroid formulations.

Adhesion formation is a major source of postoperative morbidity and mortality. In this study, the ability of a variety of lazaroid formulations [the antioxidant 21-aminosteroid PNU74006F (tirilazad) and the non-steroidal 2-methylaminochroman derivative PNU83,836E] to reduce i.p. adhesion formation in three rabbit models was examined. In initial studies, PNU83836E was administered via Alzet miniosmotic pump to the site of injury. In the sidewall and double uterine horn models, PNU83,836E was administered via Alzet miniosmotic pump for the entire postoperative interval. In the sidewall model, there was a dose-dependent reduction in the area of the sidewall injury that was involved in adhesions. In the double uterine horn model, PNU83,836E was administered via Alzet miniosmotic pump to the area of injury for 1, 2, 3 or 7 days. Administration for as little as 24 h after surgery significantly reduced the extent of adhesion formation and the reduction was increased if it was administered for longer. Further studies were conducted in which various lazaroid formulations were administered as a bolus at the end of surgery. In both the sidewall and double uterine horn models, administration of either PNU83,386E (in citrate buffer) or PNU74006F (in cyclodextrin or lipid emulsion vehicles) at the end of surgery reduced adhesion formation. Administration of a bolus of PNU74006F 10 min prior to initiation of surgery with or without additional treatment at the end of surgery further increased its efficacy in the reduction of adhesion formation. Administration of a minimum of 1.5 mg before and after surgery (3 mg total) was required for maximal efficacy. These studies demonstrate that pre- and postoperative administration of either a steroidal (PNU74006F) or non-steroidal (PNU83,836E) lazaroid intraperitoneally reduced the formation and reformation of postoperative adhesions in three animal models.

Reduction of adhesion formation by intraperitoneal administration of various anti-inflammatory agents.

Adhesion formation is a major source of postoperative morbidity and mortality. Therefore, the reduction of postoperative adhesion formation would be of clinical benefit. Various modalities have been shown to reduce adhesion formation, including fibrinolytic enzymes, nonsteroidal anti-inflammatory drugs, and barriers that reduce the apposition of sites of potential adhesion formation. In this report, the ability of three compounds with different mechanisms of action, all-trans-retinoic acid, quinacrine, and dipyridamole, to reduce the formation of intraperitoneal adhesions was examined in two rabbit models. In the sidewall model, the medicaments were administered via an Alzet miniosmotic pump for the entire postoperative interval. With all three agents, there was a reduction in the area of the sidewall injury that was involved in adhesions to the cecum and the bowel at both doses tested. In the same model, quinacrine also reduced the area of the sidewall injury that was involved in adhesions to the cecum and the bowel. At the higher concentrations of quinacrine, there was a deposition and walling off of the quinacrine at the site of delivery. In the double uterine horn model (DUH), the medicaments were administered via an Alzet miniosmotic pump to the area of injury for either 1, 2, 3, or 7 days. Administration of all three compounds for as little as 24 h after surgery significantly reduced the extent of adhesion formation. However, there was a further reduction in the amount of adhesion when the retinoic acid or dipyridamole was administered for 72 h postoperatively. However, when the quinacrine was administered for longer times postoperatively, the amount of adhesion reduction observed was less. These studies demonstrate that postoperative administration of retinoic acid, quinacrine, or dipyridamole to the site of injury reduced the formation of postoperative adhesions in two animal models.

Clinical evaluation of 0.5% ferric hyaluronate adhesion prevention gel for the reduction of adhesions following peritoneal cavity surgery: open-label pilot study.

The objective of this study was to assess the safety and to make a preliminary assessment of the efficacy of 0.5% ferric hyaluronate adhesion prevention gel in reducing adhesions in patients undergoing peritoneal cavity surgery by laparotomy, with a planned 'second-look' laparoscopy. The study was a randomized, open-label, placebo-controlled, parallel-group design in patients desirous of fertility at the Women's and Children's Hospital, Department of Obstetrics and Gynecology, University of Southern California School of Medicine, Los Angeles, California. Female patients aged 24 to 41 years received 300 ml 0.5% ferric hyaluronate adhesion prevention gel or lactated Ringer's solution as an intraperitoneal instillate at the completion of the laparotomy procedure. At second-look laparoscopy 4-12 weeks after the laparotomy, the presence of adhesions was evaluated. Haematology and serum chemistry were determined throughout the study interval. All patients tolerated the procedures well and did not manifest any serious adverse events. At second-look laparoscopy, patients treated with 0.5% ferric hyaluronate adhesion prevention gel had significantly fewer adhesions than control patients. When adhesions did form, they were significantly less extensive and less severe in patients who received 0.5% ferric hyaluronate adhesion prevention gel. In conclusion, 0.5% ferric hyaluronate adhesion prevention gel was safe and highly efficacious in the reduction of the number, severity and extent of adhesions throughout the entire abdomen following peritoneal cavity surgery.

Acceleration of dermal tissue repair by angiotensin II.

Angiotensin II is a naturally occurring peptide which has been shown to possess angiogenic properties. In the studies reported here, angiotensin II was shown to increase the proliferation of cultured bovine aortic arch endothelial cells in a concentration-dependent manner. Acute administration of angiotensin II in Hydron accelerated the repair of dermal injuries in a full-thickness excisional rat model. Additional studies were done to determine the best vehicle for delivery of angiotensin II to a dermal injury. Several vehicles, including 10% low-viscosity carboxymethyl cellulose, 4% medium-viscosity carboxymethyl cellulose, and 3% high-viscosity carboxymethyl cellulose, were found to be effective in this regard. Daily administration of angiotensin II for days 0 to 4 after injury (day 0 being the time of surgery) was determined to provide the optimal dosage for acceleration of wound repair by angiotensin II. In addition, dose-response studies indicated that angiotensin II accelerated wound repair in a dose-dependent fashion with 0.03 and 0.01 microg/rat/day of angiotensin II administered on days 0 to 4 being the minimally effective and no-effect doses, respectively. Administration of 100 microg/day of angiotensin II in 10% carboxymethyl cellulose for 5 days after injury to animals with impaired healing (steroid- and adriamycin-treated rats and diabetic mice) was also found to accelerate the rate of repair. In conclusion, angiotensin II accelerated the closure of full-thickness skin injuries in a dose-dependent manner in normal and impaired animal models.

Reduction of adhesion formation with hyaluronic acid after peritoneal surgery in rabbits.

OBJECTIVE: To examine the effect of hyaluronic acid, a high-molecular-weight glucosaminoglycan found in the extracellular matrix, on the formation of adhesions, a major source of postoperative complications. DESIGN: The ability of hyaluronic acid to reduce adhesion formation was evaluated using a standardized rabbit model. The material was administered i.p. at the end of surgery. SETTING: University laboratory. ANIMAL(S): New Zealand White female rabbits. INTERVENTION(S): Intraperitoneal administration of various formulations of hyaluronic acid at the end of surgery. MAIN OUTCOME MEASURE(S): One week after surgery, a second laparotomy was performed and the extent of adhesion formation was determined. RESULT(S): Five separate molecular weight ranges of hyaluronic acid representing eight viscosities between 1,000 and 12,000 centipoise (CPS) were shown to reduce adhesion formation in this model. All volumes, 1 to 30 mL, of hyaluronic acid tested reduced adhesion formation. In addition, the low-viscosity, low-molecular-weight hyaluronic acid significantly reduced adhesion formation when added to the trauma site or when injected at a site remote from the trauma area. CONCLUSION(S): This study showed that hyaluronic acid administered at the end of surgery reduced adhesion formation.

Reduction of adhesion formation by intraperitoneal administration of anti-inflammatory peptide 2.

Adhesion formation is a major source of postoperative morbidity and mortality. Therefore, the reduction of postoperative adhesion formation would be of clinical benefit. Various modalities have been shown to reduce adhesion formation, including fibrinolytic enzymes, nonsteroidal anti-inflammatory drugs, and barriers that reduce the apposition of sites of potential adhesion formation. This study examined the ability of a phospholipase A2 inhibitor, anti-inflammatory peptide 2 (antinflammin), to reduce the formation of intraperitoneal adhesions in two rabbit models of adhesion formation. In the sidewall model, antinflammin was administered via Alzet miniosmotic pump for the entire postoperative interval, and there was a dose-dependent reduction in the area of the sidewall injury that was involved in adhesions to the cecum and the bowel. In the double uterine horn model, antinflammin was administered via Alzet miniosmotic pump to the area of injury for either 1, 2, 3, or 7 days. Administration of antinflammin for as little as 24 h after surgery significantly reduced the extent of adhesion formation. Administration of the peptide for longer periods of time did not further increase the reduction in adhesion formation. These studies clearly demonstrate that postoperative administration of antinflammin to the site of injury reduced the formation of postoperative adhesions in two animal models.

Alterations of angiotensin II Receptor levels in sutured wounds in rat skin.

Angiotensin II receptor levels have been shown to vary with postoperative time in tissue harvested from full-thickness dermal excisional wounds on adult rats. This study examined the expression of AII receptors in a sutured wound model. Two full-thickness incisional wounds were made in the dorsal skin of adult Sprague-Dawley rats and sutured immediately under general anesthesia. The wound tissues were harvested at 0, 0.5, 1, 2, 4, 24 h and on days 2, 3, 4, 5, 7, and 10 after the wounding. The levels of 125I-Sar1.Ile8-AII bound to membrane preparations of the wound tissues decreased at early time points (from 0.5 to 4 h), increased from day 1 to day 7, and returned to nonsurgical levels by day 10. Competitive binding studies showed that the receptors were predominantly of the AT1 receptor subtype. These results suggest that an immediate and transient reduction in AII receptor expression occurred after wounding, followed by an increase in the number of AII receptors that was maintained for 5 to 7 days postoperatively. Because these data are consistent with those observed after excisional wounding, temporal changes in AII receptor expression may be integral to the process of wound healing.

Reduction of adhesion formation by intraperitoneal administration of a recombinant Hirudin analog.

Adhesion formation is a major source of postoperative morbidity and mortality. Therefore, the reduction of postoperative adhesion formation would be of clinical benefit. Various modalities have been shown to reduce adhesion formation, including fibrinolytic enzymes, nonsteroidal anti-inflammatory drugs, and barriers that reduce the apposition of sites of potential adhesion formation. This study examined the ability of an inhibitor of thrombin, a recombinant hirudin analog (recHirudin), to reduce the formation of intraperitoneal adhesions in two rabbit models of adhesion formation. In the sidewall and double uterine horn models, recHirudin was administered via Alzet miniosmotic pump for the entire postoperative interval. In both of these models, there was a dose-dependent reduction in adhesion formation as measured by (1) the area of the sidewall injury that was involved in adhesions to the cecum and the bowel or (2) the involvement of the uterine horns to themselves or other peritoneal organs. These studies clearly demonstrate that postoperative administration of recHirudin to the site of injury reduced the formation of postoperative adhesions in two animal models.

Alterations of angiotensin II receptor levels in full-thickness excisional wounds in rat skin.

Angiotensin II was recently shown to have a growth-promoting role after vascular injury and in the development of cardiac hypertrophy and fibrosis. In addition, angiotensin II may play a role in dermal wound repair. In this article, alterations in angiotensin II receptor levels in tissue harvested from full-thickness excisional dermal wounds in adult Sprague-Dawley rats were examined. A 2.25 cm(2) full-thickness excision of the dorsal skin was made under general anesthesia, and the tissue was harvested on days 1, 3, 5, 7, and 10 after wounding. The level of (125)I-Sar(1).IIe(8)-angiotensin II bound to membrane preparations of both granulation tissue and wound edge increased from day 1, peaked on day 5, and returned to nonsurgical levels by day 10. In both granulation and wound edge segments of the injured skin, the maximum binding on postoperative day 5 was about twice that of postoperative day 1 tissue or control skin. Competitive binding studies with angiotensin II type 1 receptor or type 2 receptor antagonists (DuP 753 and CGP 42112B, respectively) showed that the receptors present in the healing dermal tissue from the adult rat were almost entirely of the type 1 receptor form.

Comparative efficacy of nonsteroidal anti-inflammatory drugs and anti-thromboxane agents in a rabbit adhesion-prevention model.

A variety of nonsteroidal anti-inflammatory drugs (NSAIDs) has been found to inhibit postsurgical peritoneal adhesion formation in a number of animal models. A rabbit uterine horn adhesion model was used to directly compare several commonly used NSAIDs of different chemical classes in a single animal study to evaluate their ability to prevent adhesion formation. The effect of thromboxane inhibitors on adhesion prevention was also evaluated. Each of the NSAIDs tested (tolmetin, ibuprofen, aspirin, and indomethacin) showed significant and comparable efficacy. In this same study, imidazole, a thromboxane synthetase inhibitor, also showed significant efficacy. In a second study, ridogrel, an inhibitor of thromboxane synthetase as well as a thromboxane A2 receptor blocker, also showed significant efficacy in reducing peritoneal adhesion severity. These results further support the view that NSAIDs act to prevent adhesions through a common mechanism. In addition, thromboxane A2 inhibitors were also shown to be efficacious in adhesion prevention, suggesting that platelets may play a substantial role in adhesion formation.

Efficacy of tolmetin sodium for adhesion prevention in rabbit and rat models.

Tolmetin sodium's efficacy in preventing primary adhesions was evaluated in two adhesion models each in two species: (1) rabbit uterine horn, (2) rat uterine horn, (3) rabbit peritoneal side wall, and (4) rat peritoneal side wall. In each model a single instillation of tolmetin sodium solution into the peritoneal cavity at the time of surgery effectively reduced adhesion formation. This efficacy extended over a wide range of concentrations, volumes, and total dosages, and was similar in rabbits and rats. An aqueous solution of 1 mg/ml tolmetin sodium in 5-15 ml in rabbits and in 3 ml in rats was consistently efficacious in reducing postoperative adhesion formation.

Modulation of cytotoxic activity of resident macrophages by postsurgical macrophages.

The purpose of this study was to determine if the secretion of cytotoxic molecules, such as tumor necrosis factor or toxic oxygen molecules, by resident peritoneal macrophages is modulated by postsurgical macrophages elicited by peritoneal trauma. Resident macrophages were collected from nonsurgical rabbits and cultured in vitro with either spent media from cultures of postsurgical macrophages harvested at various times or with varying concentrations of standard cytokines. Superoxide anion (O2-) production of resident macrophages increased with exposure to spent culture media from macrophages obtained after intestinal reanastomosis (3, 6, 12, 24 hr). This increase reached maximal levels by 6 hr after surgery and thereafter decreased to resident levels by 24 hr after surgery. Exposure of resident macrophages to spent media from cells collected after peritoneal sidewall abrasion (1, 3, 5, 7, 10, 14 days) elevated the production of O2- on Postsurgical Days 3 and 5; however, no effect was observed following exposure to spent media of macrophages harvested on Postsurgical Day 14. Interleukin-1 alpha (IL-1 alpha), transforming growth factor beta (TGF-beta), and tumor necrosis factor alpha (TNF alpha) stimulated phorbol ester-induced O2- production by resident macrophages in a concentration-dependent manner. The secretion of TNF activity by resident macrophages increased following exposure to spent media of macrophages harvested 6 to 24 hr after intestinal surgery. IL-1 alpha, TGF-beta, and TNF alpha elevated the secretion of TNF activity by resident macrophages in a concentration-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Peritoneal lavage fluid protease levels after in vivo administration of tolmetin in hyaluronic acid.

Tolmetin sodium in a hyaluronic acid carrier (tolmetin-HA) was previously shown to reduce adhesion formation and alter the rate and extent to which wound repair cells enter the peritoneal cavity after surgery. In this study, the effect of tolmetin-HA on the levels of protease activities present in lavage fluid from the peritoneal cavity was determined at various postsurgical times. Collagenase activity in peritoneal lavage fluid was suppressed at 6, 12, and 24 hr after administration of tolmetin-HA in comparison to control. Elastase activity levels were biphasic with peak levels at 6 and 72 hr in lavage fluid from controls compared to peak levels at 6 and 48 hr in lavage fluid from treated rabbits. Plasminogen activator activity present in lavage fluid was significantly decreased at 48 hr after surgery in the tolmetin-HA-treated rabbits compared to controls. However, no alteration in the level of plasminogen activator inhibitor activity was observed in either the tolmetin-HA-treated or control rabbits. These data suggest that tolmetin-HA treatment altered the levels of neutral protease activity present in the peritoneal cavity and may therefore effect the proteolytic potential in the peritoneal cavity after surgery.

In vivo administration of tolmetin in hyaluronic acid modulates protease levels in postsurgical macrophage-conditioned media.

Tolmetin sodium in a hyaluronic acid carrier (tolmetin-HA) was previously shown to reduce adhesion formation and alter the kinetics and levels of cellular influx into the peritoneal cavity after surgery. In this study, the effect of tolmetin-HA on the level of protease activity in macrophage-conditioned media was determined. The level of collagenase activity in macrophage-conditioned media was suppressed at 12 and 24 h after administration of tolmetin-HA. Alternatively, the peak level of elastase activity measured in macrophage-conditioned media was unchanged after tolmetin-HA treatment, but the kinetics of expression of maximal protease activity was delayed from 12 h in the control surgical rabbits to 24 h in tolmetin-HA-treated rabbits. Elevated plasminogen activator activity was detected in acid-treated conditioned media from the tolmetin-HA-treated rabbits when compared to control levels. However, no alteration in the level of plasminogen activator inhibitor activity was present in conditioned media of macrophages harvested from tolmetin-HA-treated rabbits compared to controls. These data suggest that tolmetin-HA treatment altered the levels of neutral protease activity secreted by postsurgical macrophages and may therefore elevate the fibrinolytic potential of the peritoneal cavity after surgery.

Modulation of postsurgical macrophage function by early postsurgical polymorphonuclear leukocytes.

Surgical trauma to the peritoneum, in the absence of infection, elicits a rapid and transient influx of polymorphonuclear leukocytes (PMNs) into the peritoneal cavity prior to the accumulation of macrophages. The aim of this study was to characterize the effects of these PMNs on macrophage function in the early postsurgical period. Rabbits underwent intestinal reanastomosis and peritoneal exudate cells were collected at various times after surgery. Macrophage-enriched preparations were incubated with spent media from cultures of PMNs obtained at the corresponding times after surgery. Superoxide anion (O2-) release by macrophages in response to phorbol myristate acetate was determined by cytochrome c reduction. Fibrinolytic and protease inhibitory activities in macrophage-spent media were also evaluated. The release of O2- had already increased at 2 hr, reached peak levels at 6 hr, and decreased by 24 hr after surgery. Spent media from PMNs harvested 6 hr after surgery suppressed, whereas spent media from postsurgical 12- or 24-hr PMNs increased O2- release from macrophages harvested at 6 and 12 hr after surgery. PMN-spent media had no effect on the secretion of plasminogen activator (PA) from macrophages harvested within 12 hr after surgery. In contrast, PA activity in the spent media from macrophages harvested 24 hr after surgery was elevated after exposure to PMN-spent media. PA inhibitory activity was reduced in macrophage-spent media at 2 hr after surgery and increased by 24 hr, while PMN-spent media had no effect on the level of PA inhibitory activity. Thus, soluble factors secreted into the culture medium by PMNs modulate macrophage function as soon as 6-12 hr after surgery.

Effects of interleukin-1 (IL-1) on postsurgical macrophage secretion of protease and protease inhibitor activities.

Although peritoneal macrophages secrete a variety of inflammatory mediators and proteases during postsurgical repair of the peritoneum, regulation of this secretion is poorly understood. Here, the responsivity of peritoneal macrophages to interleukin-1 (IL-1) stimulation in vitro, measured by the secretion of protease and protease inhibitor activities, was evaluated as a function of postsurgical time. Macrophages were harvested at various times after peritoneal sidewall abrasion, isolated by discontinuous density centrifugation and cultured with varying concentrations of IL-1. IL-1 increased the secretion of plasminogen activator (PA) activity by peritoneal macrophages in a concentration-dependent manner on postsurgical Days 0, 3, 10, and 14. Macrophages harvested on postsurgical Day 1 after surgery responded only to high concentration of IL-1, while on Days 5 and 7 all doses of IL-1 stimulate PA. On Days 7, 10, and 14 after surgery, the secretion of PA activity (after acid treatment) by postsurgical macrophages was generally high and increased with IL-1 treatment. The level of PA activity after inactivation of acid labile inhibitors (PAI) also increased in a dose-dependent manner on Days 0, 3, and 5. Although Day 1 macrophages expressed the highest PAI activity of all groups, they had relatively low responsivity to IL-1 with regards to PAI secretion. The level of elastase activity by postsurgical macrophages was lowest on Day 1, highest on Day 7, and decreased thereafter. All concentrations of IL-1 inhibited elastase activity of macrophages on Day 7.(ABSTRACT TRUNCATED AT 250 WORDS)