Peritoneal macrophages modulate human granulosa-luteal cell progesterone production

Macrophages have been identified in the developing corpus luteum in several species, including man, and also constitute approximately 90% of cells in the peritoneal cavity. We studied the effect of peritoneal macrophages or blood monocytes on progesterone (P) synthesis by human granulosa cells from preovulatory follicles obtained at laparoscopy of 14 women undergoing in vitro fertilization. Pooled granulosa cells from follicles with mature ova were isolated by Ficoll-Hypaque gradient centrifugation. Washed granulosa cells (0.75 X 10(5)/ml) were incubated in Dulbecco's Minimum Essential Medium containing 20% calf serum with varying concentrations of pelvic macrophages (0.8-29 X 10(5)/ml) or fresh and mature blood monocytes (0.25-2.5 X 10(5)/ml). P production was determined by RIA of medium at 24-h intervals for 24-48 h. In situ concentrations of pelvic macrophages from 8 patients with tubal infertility increased cumulative P production to 140 +/- 17.8% (mean +/- SEM) of the control values. A similar increase (182 +/- 62.7%) was found with macrophages from 6 patients with endometriosis or unexplained infertility. Both fresh and mature monocytes stimulated P production to 225% and 261% of control values, respectively. Indomethacin (10(-4) M) or monoclonal antibody to somatomedin-C did not prevent stimulation of P production. These results suggest that peritoneal macrophages may exert luteotropic effects on cumulus cells while the ovulated oocyte resides in the tube, and incoming monocytes may be important in stimulating luteal cells in the developing corpus luteum.     

Peritoneal fluid and plasma levels of human macrophage colony-stimulating factor in relation to peritoneal fluid macrophage content

The peritoneal fluid (PF) of women with infertility (especially in the presence of endometriosis) contains increased numbers of leukocytes, 90% to 95% of which are macrophages. The high numbers of peritoneal macrophages presumably result from an influx of blood monocytes into the peritoneum, and/or from local proliferation of peritoneal macrophages. Once in the peritoneal cavity, monocytes differentiate into tissue macrophages. Mononuclear phagocyte proliferation and differentiation are influenced by different cytokines, including macrophage colony-stimulating factor (M-CSF). The purpose of this study was to determine the relationship of M-CSF levels in human PF and plasma to the macrophage content, and to the patient diagnoses. Mean concentrations of PF M-CSF were higher than plasma levels (2.44 +/- 0.13 v 0.95 +/- 0.06 ng/mL, respectively). The mean concentrations of plasma M-CSF did not differ in samples from women of different diagnostic groups (normal, peritoneal adhesions, endometriosis, inactive pelvic inflammatory disease, uterine fibroids, and idiopathic infertility), but the PF concentration was slightly higher in normal women. The absolute (total) amount of PF M-CSF in normal women was lower than in those of the other diagnostic groups. The total amount of PF M-CSF in all women correlated closely with the total number of peritoneal macrophages. The tubal patency status (open versus closed) did not influence the plasma and PF concentrations of M-CSF, nor the PF absolute amount of M-CSF. The PF M-CSF may have come from peritoneal macrophages, fibroblasts, mesothelial cells, or endothelial cells. PF M-CSF may play important roles in the proliferation and/or the differentiation of peritoneal mononuclear phagocytes.     

Intra-alveolar release of a competence-type growth factor after lung injury

Growth factors released by platelets, macrophages, and endothelial and smooth muscle cells have been recognized and characterized using in vitro tests of isolated cell populations. However, their production, secretion, and effects on target cells in situ after tissue injury remains largely presumptive. Alveolar macrophages cultured during acute and chronic lung injury release increased amounts of macrophage-derived growth factor (MDGF). In the present study, we sampled the alveolar lining fluid by lavage for the presence of macromolecular competence factor activity. We report that alveolar lavage fluid obtained following acute lung injury induced by bleomycin in the rat contains large amounts of soluble growth factor activity not found in lung lavage fluid from normal animals. We compared the properties of the growth factor found in fresh lavage fluid to MDGF and platelet-derived growth factor (PDGF). The amount of growth factor in lavage fluid paralleled the ability of cultured alveolar macrophages to release MDGF. Like PDGF and MDGF, lavage fluid growth factor served as a competence factor promoting the reentry of quiescent fibroblasts into the cell cycle rather than as a progression factor. Chromatography on DEAE-Sephacel yielded a single peak of growth factor activity eluting at 0.3 M NaCl. On the basis of these and other physical and biologic properties, we conclude that growth factor activity found in high levels in the alveolar space following acute lung injury resembles MDGF. Growth factor present in the alveolar space may provide the major local stimulus to lung structural cell replication after acute lung injury.     

What is new about endometriosis?

Endometriosis concerns 6 to 10 % of the female population, and is responsible for severe pelvic pain and infertility. This estrogen dependant disease, is characterized by the presence of endometrial tissue outside of the uterus cavity. Although his physiopathology remains poorly understood, recent data have focused on angiogenesis, which could represent a key factor for the growing of lesions of endometriosis. New antiangiogenesis treatments represent a therapeutic hope, and have been tested in vitro or in vivo in mice. Those drugs have proven their efficacy on endometriotic lesions. Secondly, several hypothesis are discussed to explain infertility in endometriosis. In particular, a direct impact of peritoneal fluid from women with endometriosis on sperm DNA could be involved.     

Expression of allograft inflammatory factor-1 in human eutopic endometrium and endometriosis: possible association with progression of endometriosis

Allograft inflammatory factor-1 (AIF-1) is a cytokine originally identified in rat cardiac allografts with chronic rejection. AIF-1 is expressed in various human immune-related tissues and is thought to play a role in inflammatory responses and the immune activation and function of macrophages. Expression has also been shown in human placentas and bovine embryos, suggesting that AIF-1 may be involved in reproductive function. Immune factors are thought to be involved in the pathogenesis of endometriosis. High concentrations of activated macrophages and various cytokines have been found in the peritoneal fluid of patients with endometriosis. In the current work we examined the expression of AIF-1 in human eutopic endometrium and endometriosis, and measured AIF-1 in peritoneal fluid samples from women with and without endometriosis. RT-PCR, Western blot analysis, and immunohistochemistry showed that AIF-1 mRNA and protein were expressed both in eutopic endometrium and in endometriotic tissue. In eutopic endometrium, expression was greater in the late secretory and menstrual phases than in other phases of the menstrual cycle (P < 0.01). AIF-1 protein was present in greater amounts in peritoneal fluid from patients with endometriosis than in women without it (P < 0.01), and its concentration correlated with the Revised American Society for Reproductive Medicine score (rs = 0.693; P < 0.0001). Peritoneal macrophages from endometriosis patients secreted more AIF-1 than those from unaffected women (P < 0.05). AIF-1 release from macrophages was stimulated by IL-1beta (P < 0.01) and interferon-gamma (P < 0.05). These results demonstrate for the first time that AIF-1 is expressed in eutopic endometrium and endometriotic tissue, suggesting that AIF-1 is one cytokine in the local network involved in the onset of menstruation. AIF-1 derived from peritoneal macrophages may also possibly play a significant role in the pathophysiology and progression of endometriosis.     

Identification of cystatin C, a cysteine proteinase inhibitor, as a major secretory product of human alveolar macrophages in vitro

The major inhibitor of the cysteine class of proteinases found in human body fluids, such as spinal fluid, milk, and seminal plasma, is cystatin C. In this study we show that human bronchoalveolar fluid also contains cystatin C and examine cystatin C expression by alveolar macrophages in vitro. Immunoprecipitation of extracts of metabolically labeled cells and immunoblotting of cellular extracts and culture media show that cystatin C is synthesized as a 14 (+/- 0.5) kilodalton (kD) protein and that greater than 90% of the protein is released as the 14 kD product into the culture supernatant (26.5 +/- 6.8 ng per 10(6) cells per 24 h). Cystatin C is not one of the most abundant proteins secreted during the first 24 h in vitro, representing approximately 10 to 12% of the total protein released by normal nonsmoker macrophages. Alveolar macrophages obtained from cigarette smokers or nonsmoker macrophages exposed to zymosan in vitro released 10 to 55% less cystatin C than nonsmoker macrophages. We also assayed culture supernatants from macrophages of smokers and nonsmokers for functional cystatin C. Supernatants of nonsmoker macrophages inhibited cathepsin B-like amidolytic activity in a fluorometric assay at pH 5.5. The inhibition was blocked by adsorption with Sepharose-coupled cystatin C antibodies and the inhibitor subsequently recovered from the Sepharose beads. In contrast, supernatants from smoker macrophages had obvious cathepsin B-like activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Peritoneal fluid,endometriosis, and ciliary beat frequency in the human fallopian tube

Endometriosis and infertility are known to be associated, but it is unclear whether endometriosis causes infertility. We used contrast analogue enhancement to study the effect of peritoneal fluid from women with early stage endometriosis on the ciliary beat frequency of human fallopian tube epithelium. We obtained peritoneal fluid from six women with early stage endometriosis and from six fertile women with no evidence of endometriosis to use as controls. Fallopian tubes from hysterectomy specimens were collected from 17 women. The difference in ciliary beat frequency between fallopian tubes exposed to peritoneal fluids of women with and without endometriosis increased with the duration of incubation (mean difference at 24 h 1.35 Hz, 95% CI 0.94-1.75, p=0.01). At 24 h, ciliary beat frequency was significantly lower in the incubations with peritoneal fluid from women with endometriosis than controls (4.29 [0.15] vs 5.64 Hz [0.15], respectively, p=0.001). Impairment of ciliary action in women with endometriosis might reduce fertility.     

Production and secretion of complement component 3 by endometriotic tissue

Many investigators have described a variety of immune phenomena associated with endometriosis. Among these are elevated titers of activated macrophages, monokines, and lymphokines in the peritoneal fluid of patients with endometriosis. In 1980, Weed and Arquembourg first described the deposition of complement component C3 in epithelial cells of endometrial glands in patients with endometriosis. In this study our objective was to examine the synthesis and secretion of proteins by endometriotic tissue. Tissues were incubated in Minimal Essential Medium without methionine containing 50 microCi/mL [35S]methionine for 12-16 h at 37 C in 5% CO2-95% air. Twenty thousand trichloroacetic acid-precipitable counts were placed on a 7.5% sodium dodecyl sulfate-polyacrylamide gel, and the radiolabeled proteins were detected by fluorography. We examined the radiolabeled secretory proteins obtained from 17 endometriotic implants and/or endometrioma cyst walls as well as 8 control tissues. A 180 kDa protein was produced in much greater quantities by endometriotic tissue than by control tissues. In the presence of reducing agent this protein dissociated into 113- and 69-kDa subunits. To identify and quantitate this protein we performed immunoprecipitations on the incubated medium using antihuman C3 immunoglobulin G. Up to 16% of the precipitable counts were recovered with this antibody from endometriotic tissue, while a maximum of only 4.6% was recovered from control tissue. In addition, we isolated and incubated the epithelial glandular cells, stromal cells, and remaining cells from two endometriomas. The great majority of the newly synthesized and secreted C3 was found in the glandular epithelial cell incubation. Up to 60% of the total precipitable counts were recovered from the glandular cells using this antibody. Only one protein was immunoprecipitated. The immunoprecipitated protein had a mol wt of 180 kDa under nonreducing conditions and dissociated into two subunits of 113 and 69 kDa in the presence of dithiothreitol. We conclude that the glandular epithelial cells found in endometriotic implants produce and secrete complement component, C3 which could be responsible for many of the immunological phenomena now well described in endometriosis.     

Identification of cyclophilin as a proinflammatory secretory product of lipopolysaccharide-activated macrophages.

We have isolated an 18-kDa peptide (designated sp18, for 18-kDa secreted protein) from the conditioned medium of lipopolysaccharide-stimulated RAW 264.7 murine macrophages. Purified sp18 had in vivo inflammatory activity and in vitro chemotactic activity for human peripheral blood polymorphonuclear leukocytes and monocytes. Surprisingly, N-terminal sequencing and tryptic mapping studies revealed that sp18 and cyclophilin, an intracellular protein that binds the immunosuppressive drug cyclosporin A, are highly homologous. The in vitro chemotactic activity of sp18 on monocytes was blocked by cyclosporin A but not by cyclosporin H, a structural analog of cyclosporin A that does not bind cyclophilin. Like purified porcine cyclophilin, mouse sp18 exhibited peptidyl-prolyl cis-trans isomerase activity. Medium conditioned by lipopolysaccharide-stimulated resident peritoneal exudate macrophages isolated from C57BL/6 mice contained substantially higher levels of sp18/cyclophilin than medium conditioned by nonstimulated macrophages. The observation that sp18/cyclophilin exhibits proinflammatory activity and is secreted by macrophages in response to endotoxin suggests that this protein may function as a cytokine, and invites the hypothesis that the immunosuppressive action of cyclosporin A results in part from interaction with an extracellular form of cyclophilin released as a mediator of immune and inflammatory functions.     

Quelles nouveautés sur l’endométriose ?

Endometriosis concerns 6 to 10 % of the female population, and is responsible for severe pelvic pain and infertility. This estrogen dependant disease, is characterized by the presence of endometrial tissue outside of the uterus cavity. Although his physiopathology remains poorly understood, recent data have focused on angiogenesis, which could represent a key factor for the growing of lesions of endometriosis. New antiangiogenesis treatments represent a therapeutic hope, and have been tested in vitro or in vivo in mice. Those drugs have proven their efficacy on endometriotic lesions. Secondly, several hypothesis are discussed to explain infertility in endometriosis. In particular, a direct impact of peritoneal fluid from women with endometriosis on sperm DNA could be involved.     

Neutrophils and macrophages promote angiogenesis in the early stage of endometriosis in a mouse model

Substantial evidence suggests that inflammatory cytokines, immune cells, and angiogenesis are important for endometriosis. In this study, we investigated the role of the sequential events in the development of endometriosis in a mouse model. Uterine tissue was transplanted into the peritoneum of ovariectomized mice and then supplemented with estrogen or vehicle. On different days after transplantation, cell proliferation, angiogenesis, and infiltrated immune cells in ectopic tissue were examined using immunochemical staining. Many disintegrated blood vessels but no bromodeoxyuridine-positive cells in ectopic tissue were observed in the estrogen-treated group on posttransplantation d 1 and 2. On d 4-7, bromodeoxyuridine-positive cells were detected in the blood vessels of ectopic tissue, indicating that angiogenesis was initiated in this stage. Angiogenesis also occurred in ectopic tissue in the vehicle-treated group. Profound infiltration of neutrophils in ectopic tissue occurred on d 1-4, when the number of neutrophils and levels of macrophage inflammatory protein (MIP)-1alpha and MIP-2 chemokines in peritoneal fluids also reached their peak. Peritoneal macrophage numbers did not change, but secretions of TNFalpha, IL-6, MIP-1alpha, and MIP-2 from macrophages isolated on d 2 were higher than on d 0. In vitro studies showed that peritoneal neutrophils and macrophages secreted vascular endothelial growth factor, which was up-regulated by TNFalpha and IL-6. Our results suggest that neutrophils and macrophages may promote angiogenesis in the early stage of endometriosis and that chemokines and cytokines amplify the angiogenic signal for the growth of endometriotic tissue.     

Anomalies in the inflammatory response in endometriosis and possible consequences: a review

Defined by the presence of endometrial-like cells outside the uterus, endometriosis is one of the most diagnosed gynecological disorders, affecting 5 to 10 % of reproductive age women, but the true incidence is unknown. Endometriosis is a major cause of pelvic pain, dysmenorrhea, dyspareunia, infertility and menstrual irregularities, but there is no clear correlation between the symptoms and the extent of the disease. Despite decades of intensive investigations, little is known about the pathogenesis of endometriosis. The disease is often associated with chronic pelvic inflammation. Abnormal levels of immune cells such macrophages, dendritic and natural killer cells were found in the peritoneal cavity of patients. However these cells seem to be unable to detect and eliminate ectopic endometrial cells. Several studies showed that peritoneal immune cells are dysfunctional and may rather contribute to endometriosis development. A review of relevant clinical and scientific studies was carried out. This review sheds light on cellular and immunological pro-inflammatory changes which were observed in patients with endometriosis, their impact on angiogenesis, apoptosis, extracellular matrix remodeling and hormonal production and consequences on fertility.     

Pulmonary endometriosis

Pulmonary endometriosis is manifested as either asymptomatic pulmonary nodules or as pneumothorax, hemothorax, or hemoptysis during menses. We review 84 cases of pulmonary endometriosis in the English literature and report 3 additional patients. One of our patients is the first reported to have hemoneumothorax. Catamenial pneumothorax usually involved the right chest, and occurred in young nulliparous women without pelvic endometrosis. Pleuroscopy, laparoscopy with pneumoperitoneum, and thoracotomy produced a tissue diagnosis infrequently. Hormonal suppression of ovulation and pleurodesis usually corrected this disorder. Catamenial hemothorax only affected the right chest, but occurred in older multiparous women with pelvic endometriosis. While thoracotomy or laparotomy produced a tissue diagnosis, these procedures were not curative. In contrast, our patient with this disorder was treated successfully with pleurectomy. Catamenial hemoptysis occurred in multiparous women without pelvic endometriosis. Bronchoscopy localized bleeding but never produced a tissue diagnosis. Thoracotomy produced endometrial tissue. Endometrial pulmonary nodules require a diagnosis but do not otherwise produce problems.     

Interaction of transferrin with iron-loaded rat peritoneal macrophages

Rat peritoneal macrophages are capable, in vitro, of processing and releasing iron derived from phagocytosed, immunosensitized red cells. From 20% to 60% of the red cell iron can be returned to the culture medium in 24 h, with resident macrophages more active than inflammatory, peptone-induced macrophages. When apotransferrin is present in the culture medium, from 39% to 72% of iron released from macrophages is bound to the protein, with most of the remainder in a ferritin-like form. No distinct preference of released iron for either site of transferrin could be observed. The absence of apotransferrin depresses iron release only slightly, with much of the iron then released in a form readily available to the protein in vitro. Pronase treatment of macrophages, which abolishes their ability to bind transferrin, depresses iron release no more than 10-15%. It appears, therefore, that binding of apotransferrin to macrophages may not be essential for iron excretion by the cells.     

Nuclear peroxisome proliferator-activated receptors alpha and gamma have opposing effects on monocyte chemotaxis in endometriosis.

The peroxisome proliferator-activated receptors (PPARs) alpha and gamma are nuclear receptors that play important roles in inflammatory diseases like ulcerative colitis and arthritis. In this study, we examined the possible role of PPARs in macrophage attraction into the peritoneal cavity of patients with endometriosis. We identified PPAR-alpha and -gamma messenger RNA by RT-PCR and protein by immunoblotting of lysates of peritoneal macrophages and monocytic U937 cells. Using immunocytochemistry, we localized PPAR-alpha and -gamma within the nuclei of both cell types. Monocyte chemotactic activity of peritoneal fluid from patients with endometriosis was quantified in Boyden chambers. Migration of U937 cells was increased by WY 14643 and reduced by rosiglitazone. Peritoneal fluid from patients with endometriosis activated U937 cells transiently transfected with a PPAR-alpha/GAL4 luciferase reporter. By contrast, peritoneal fluid did not cause significant activation of PPAR-gamma/GAL4 constructs. The U937 cells transiently transfected with a PPAR response element luciferase reporter showed disease stage-dependent up-regulation when treated with peritoneal fluid from patients with endometriosis. Treatment with peritoneal fluid from healthy controls down-regulated PPAR response element transactivation. We conclude that peritoneal fluid of endometriosis patients contains activators of PPAR-alpha that stimulate macrophage chemotaxis. Inhibitors of PPAR-alpha or activators of PPAR-gamma could be developed for the treatment of inflammation associated with endometriosis.     

Bowel endometriosis: Colorectal surgeon’s perspective in a multidisciplinary surgical team

Endometriosis is a gynecological condition that presents as endometrial-like tissue outside the uterus and induces a chronic inflammatory reaction. Up to 15% of women in their reproductive period are affected by this condition. Deep endometriosis is defined as endometriosis located more than 5 mm beneath the peritoneal surface. This type of endometriosis is mostly found on the uterosacral ligaments, inside the rectovaginal septum or vagina, in the rectosigmoid area, ovarian fossa, pelvic peritoneum, ureters, and bladder, causing a distortion of the pelvic anatomy. The frequency of bowel endometriosis is unknown, but in cases of bowel infiltration, about 90% are localized on the sigmoid colon or the rectum. Colorectal involvement results in alterations of bowel habits such as constipation, diarrhea, tenesmus, dyschezia, and, rarely, rectal bleeding. Differential diagnosis must be made in case of irritable bowel syndrome, solitary rectal ulcer syndrome, and a rectal tumor. A precise diagnosis about the presence, location, and extent of endometriosis is necessary to plan surgical treatment. Multidisciplinary laparoscopic treatment has become the standard of care. Depending on the size of the lesion and site of involvement, full-thickness disc excision or bowel resection needs to be performed by an experienced colorectal surgeon. Long-term outcomes, following bowel resection for severe endometriosis, regarding pain and recurrence rate are good with a pregnancy rate of 50%.     

No constitutive defect in phagocytosis of apoptotic cells by resident peritoneal macrophages from pre-morbid lupus mice

Antibodies against nucleosomes are a hallmark of systemic lupus erythematosus (SLE). Nucleosomes are uniquely formed during apoptosis, through cleavage of chromatin by nucleases. Increased exposure of nucleosomes to the immune system could play a role in the induction of the autoimmune repertoire in SLE. To determine whether there exists a constitutive defect in the clearance of apoptotic cells, resident peritoneal macrophages from pre-morbid SLE-prone MRL and New Zealand (NZ) mice were analysed for their efficacy to phagocytose apoptotic cells in vitro. Although differences in phagocytic efficacy of up to 50% between different strains of mice were found, these were not related to SLE development. To evaluate whether macrophages from SLE-prone mice are more susceptible to phagocytic 'exhaustion', resident peritoneal macrophages were challenged by 20 h of additional culture in the presence of apoptotic cells. In both lupus and control strains this led to an increased capacity to phagocytose fresh apoptotic cells (increase between 15 and 92%). As a control, macrophages from all strains were also exposed to 20 h of additional culture without apoptotic cells. Under this condition resident peritoneal macrophages from all SLE-prone strains, and of the SLE-parental strain NZB, displayed a significant decrease in their efficacy to phagocytose apoptotic cells (decrease between 16 and 55%). Together, these findings do not support the hypothesis that a constitutive defect in the clearance of apoptotic cells, as evaluated by testing resident peritoneal macrophages, plays an important role in the induction of SLE.     

Purification and biochemical properties of a human monocyte-derived growth factor.

A monocyte-derived growth factor (MDGF) that stimulates proliferation of fibroblast and smooth muscle cells was purified from mitogen-stimulated human peripheral blood lymphocyte conditioned medium by using anion-exchange, Bio-Sil TSK-250 HPLC gel-permeation chromatography, and NaDodSO4/PAGE. Purified MDGF exhibited acidic charge characteristics (pI 5.0) and migrated with an apparent Mr of 40,000 +/- 2000 in molecular sizing HPLC columns. Elution from NaDodSO4/polyacrylamide gels showed that the growth-promoting activity was associated with three or four protein bands. The highest molecular weight species representing the most intense silver-stained band corresponded to 42,000; the lowest molecular weight species was 33,000. MDGF activity was stable to treatment with acid (pH 2.0) or base (pH 10.0) and heating (100 degrees C, 5 min) but was inactivated upon reduction with 2-mercaptoethanol. The acidic MDGF did not effectively compete with platelet-derived growth factor (PDGF) for receptor binding and was not inhibited by PDGF antibodies. Previous studies have suggested that fibroblast growth-stimulating activity of macrophages is largely due to their secretion of interleukin 1 and a PDGF-like molecule. Our purification and biochemical characterization studies reveal the occurrence of multiple forms of fibroblast growth-stimulating activity in human monocyte conditioned medium. The MDGF activity characterized here appears to be structurally and functionally distinct from the previously described fibroblast growth-promoting activities including interleukin 1, basic fibroblast growth factor, and PDGF.     

Macrophage-conditioned medium and interleukin 1 suppress vascular contractility

Isolated rat aortas, after incubation in medium conditioned by endotoxin-stimulated peritoneal macrophages, exhibited diminished contraction to norepinephrine (maximal contraction: control medium = 713 +/- 37 (SE) mg tension/mg tissue; medium conditioned by macrophages = 437 +/- 38, P less than .001). Medium containing endotoxin alone or medium conditioned by nonstimulated macrophages had no effect on aortic tissue response to norepinephrine. Stimulation of peritoneal macrophages in vivo by sterile silica particles also induced diminished contractile responses to norepinephrine by subsequently isolated aortas. Incubation of rat aortas with human monocyte-derived interleukin 1 or recombinant human tumor necrosis factor resulted in diminished aortic contraction and sensitivity to norepinephrine, and gel filtration of medium conditioned by endotoxin-stimulated macrophages yielded suppressive activity at a molecular weight equivalent to interleukin 1 and tumor necrosis factor. The data suggest that mononuclear phagocytes may contribute to altered vascular function in sepsis via the release and vascular modulatory effects of interleukin 1 and tumor necrosis factor.     

In vivo activation of macrophages by IFN-γ to kill Entamoeba histolytica trophozoites in vitro

To determine the role of interferon-gamma (IFN-gamma) in the activation of macrophages to kill Entamoeba histolytica trophozoites in vitro, C57BL/6 mice were injected with various doses of recombinant IFN-gamma (rIFN-gamma) by either the intravenous, intraperitoneal or intramuscular routes. Mice were treated with doses of rIFN-gamma ranging from 10(1) to 10(5) units. Twenty hours later, peritoneal macrophages were harvested from the treated animals. Macrophage monolayers were prepared and their in vitro cytotoxic activity against a virulent strain of E. hystolytica (IP:0682:1) was determined. Amoebicidal activity was determined by counting the number of dead trophozoites by Trypan Blue exclusion in cultures containing macrophages and amoebic trophozoites which were incubated together for 4 h. Both intravenous and intraperitoneal treatment resulted in the recovery of macrophages from the peritoneal cavity which exhibited amoebicidal activity in vitro. Peritoneal macrophages harvested from mice that had been treated intraperitoneally or intravenously with rIFN-gamma, however, showed significantly more amoebicidal activity in comparison to macrophages harvested from animals treated intramuscularly. There was a dose dependent relationship between the concentration of rIFN-gamma used to activate macrophages in vivo and the number of dead trophozoites in vitro. In addition, these results confirm our previous observations that treatment in vitro with rIFN-gamma can activate murine peritoneal macrophages to kill amoebic trophozoites.