Adjunct antibody administration with standard treatment reduces relapse rates in a murine tuberculosis model of necrotic granulomas

Matrix metalloproteinase (MMP)-9 is a zinc-dependent protease associated with early immune responses to Mycobacterium tuberculosis infection, macrophage recruitment and granuloma formation. We evaluated whether adjunctive inhibition of MMP-9 could improve the response to standard TB treatment in a mouse model that develops necrotic lesions. Six weeks after an aerosol infection with M. tuberculosis, C3HeB/FeJ mice received standard TB treatment (12 weeks) comprising rifampin, isoniazid and pyrazinamide alone or in combination with either anti-MMP-9 antibody, etanercept (positive control) or isotype antibody (negative control) for 6 weeks. Anti-MMP-9 and the isotype control had comparable high serum exposures and expected terminal half-life. The relapse rate in mice receiving standard TB treatment was 46.6%. Compared to the standard TB treatment, relapse rates in animals that received adjunctive treatments with anti-MMP-9 antibody or etanercept were significantly decreased to 25.9% (P = 0.006) and 29.8% (P = 0.019) respectively, but were not different from the arm that received the isotype control antibody (25.9%). Immunostaining demonstrated localization of MMP-9 primarily in macrophages in both murine and human lung tissues infected with M. tuberculosis, suggesting the importance of MMP-9 in TB pathogenesis. These data suggest that the relapse rates in M. tuberculosis-infected mice may be non-specifically improved by administration of antibodies in conjunction with standard TB treatments. Future studies are needed to evaluate the mechanism(s) leading to improved outcomes with adjunctive antibody treatments.

ACE phenotyping in Gaucher disease

BACKGROUND

Gaucher disease is characterized by the activation of splenic and hepatic macrophages, accompanied by dramatically increased levels of angiotensin-converting enzyme (ACE). To evaluate the source of the elevated blood ACE, we performed complete ACE phenotyping using blood, spleen and liver samples from patients with Gaucher disease and controls.

METHODS

ACE phenotyping included 1) immunohistochemical staining for ACE; 2) measuring ACE activity with two substrates (HHL and ZPHL); 3) calculating the ratio of the rates of substrate hydrolysis (ZPHL/HHL ratio); 4) assessing the conformational fingerprint of ACE by evaluating the pattern of binding of monoclonal antibodies to 16 different ACE epitopes.

RESULTS

We show that in patients with Gaucher disease, the dramatically increased levels of ACE originate from activated splenic and/or hepatic macrophages (Gaucher cells), and that both its conformational fingerprint and kinetic characteristics (ZPHL/HHL ratio) differ from controls and from patients with sarcoid granulomas. Furthermore, normal spleen was found to produce high levels of endogenous ACE inhibitors and a novel, tightly-bound 10-30 kDa ACE effector which is deficient in Gaucher spleen.

CONCLUSIONS

The conformation of ACE is tissue-specific. In Gaucher disease, ACE produced by activated splenic macrophages differs from that in hepatic macrophages, as well as from macrophages and dendritic cells in sarcoid granulomas. The observed differences are likely due to altered ACE glycosylation or sialylation in these diseased organs. The conformational differences in ACE may serve as a specific biomarker for Gaucher disease.

Phospholipase Cγ2 Is Required for Luminal Expansion of the Epididymal Duct during Postnatal Development in Mice

Phospholipase Cγ2 (PLCγ2)-deficient mice exhibit misconnections of blood and lymphatic vessels, and male infertility. However, the cell type responsible for vascular partitioning and the mechanism for male infertility remain unknown. Accordingly, we generated a mouse line that conditionally expresses endogenous Plcg2 in a Cre/loxP recombination-dependent manner, and found that Tie2-Cre- or Pf4-Cre-driven reactivation of Plcg2 rescues PLCγ2-deficient mice from the vascular phenotype. By contrast, male mice rescued from the vascular phenotype exhibited epididymal sperm granulomas. As judged from immunostaining, PLCγ2 was expressed in clear cells in the epididymis. PLCγ2 deficiency did not compromise differentiation of epididymal epithelial cells, including clear cells, and tube formation at postnatal week 2. However, luminal expansion of the epididymal duct was impaired during the prepubertal period, regardless of epithelial cell polarity and tube architecture. These results suggest that PLCγ2-deficient clear cells cause impaired luminal expansion, stenosis of the epididymal duct, attenuation of luminal flow, and subsequent sperm granulomas. Clear cell-mediated luminal expansion is also supported by the observation that PLCγ2-deficient males were rescued from infertility by epididymal epithelium-specific reactivation of Plcg2, although the edematous and hemorrhagic phenotype associated with PLCγ2 deficiency also caused spontaneous epididymal sperm granulomas in aging males. Collectively, our findings demonstrate that PLCγ2 in clear cells plays an essential role in luminal expansion of the epididymis during the prepubertal period in mice, and reveal an unexpected link between PLCγ2, clear cells, and epididymal development.

Helminth-induced arginase-1 exacerbates lung inflammation and disease severity in tuberculosis

Parasitic helminth worms, such as Schistosoma mansoni, are endemic in regions with a high prevalence of tuberculosis (TB) among the population. Human studies suggest that helminth coinfections contribute to increased TB susceptibility and increased rates of TB reactivation. Prevailing models suggest that T helper type 2 (Th2) responses induced by helminth infection impair Th1 immune responses and thereby limit Mycobacterium tuberculosis (Mtb) control. Using a pulmonary mouse model of Mtb infection, we demonstrated that S. mansoni coinfection or immunization with S. mansoni egg antigens can reversibly impair Mtb-specific T cell responses without affecting macrophage-mediated Mtb control. Instead, S. mansoni infection resulted in accumulation of high arginase-1-expressing macrophages in the lung, which formed type 2 granulomas and exacerbated inflammation in Mtb-infected mice. Treatment of coinfected animals with an antihelminthic improved Mtb-specific Th1 responses and reduced disease severity. In a genetically diverse mouse population infected with Mtb, enhanced arginase-1 activity was associated with increased lung inflammation. Moreover, in patients with pulmonary TB, lung damage correlated with increased serum activity of arginase-1, which was elevated in TB patients coinfected with helminths. Together, our data indicate that helminth coinfection induces arginase-1-expressing type 2 granulomas, thereby increasing inflammation and TB disease severity. These results also provide insight into the mechanisms by which helminth coinfections drive increased susceptibility, disease progression, and severity in TB.

Schistosome infection-derived Hepatic Stellate Cells are cellular source of prostaglandin D₂: role in TGF-β-stimulated VEGF production

Hepatic Stellate Cells (HSCs) play a crucial role in pathogenesis of liver inflammation and fibrosis. During chronic liver injury, HSCs lose vitamin A and transform into myofibroblastic cells. In schistosomal granulomas, these activated HSCs are called GR-HSCs. Schistosomal-triggered hepatic fibrogenesis has TGF-β as the most potent fibrogenic stimulus, that also controls gene expression of the angiogenic molecule VEGF in HSCs. COX-dependent production of prostaglandins (PGs) also play role in angiogenic processes. Besides angiogenic roles, prostanoids control immunomodulation of Schistosoma mansoni infection. Specifically, schistosoma-derived PGD2 has emerged as a key parasite regulator of immune defense evasion, while no role is still established to host PGD2. Therefore, the aim of this work is to investigate the ability of GR-HSCs to synthesize COX-derived PGD2 and a potential role of this prostanoid in VEGF production by GR-HSCs in vitro. Here, we confirmed that GR-HSCs express COX-2, which displayed perinuclear localization. While unstimulated GR-HSCs produce basal levels of PGD2, TGF-β stimulation besides increasing COX2- mRNA levels, enhanced synthesis/secretion of PGD2 in GR-HSCs supernatant. Moreover, GR-HSCs-derived PGD2 mediate VEGF production by TGF-β-stimulated GR-HSCs, since the pre-treatment with HQL-79, an inhibitor of hematopoietic PGD synthase inhibited both PGD2 synthesis and VEGF secretion by TGF-β-stimulated GR-HSCs. All together, our findings show an autocrine/paracrine activity of GR-HSCs-derived PGD2 on TGF-β-induced VEGF production by GR-HSCs, unveiling a role for PGD2 as important regulator of HSCs activation in hepatic granulomas from schistosome infected mice.

A case of hepatitis C-associated osteosclerosis with xanthogranulomatous cholecystitis

A 62-year-old woman presented with a markedly increased serum ALP level of skeletal origin during a regular follow-up of chronic hepatitis C. Serum calcium, phosphorus, and intact-PTH levels were normal and bone turnover markers were increased. Her generalized bone density was diffusely increased. These findings were consistent with hepatitis C-associated osteosclerosis (HCAO). She underwent cholecystectomy, as gallbladder cancer was suspected; however, histopathological findings demonstrated xanthogranulomatous cholecystitis. After cholecystectomy, serum ALP level and bone turnover markers were gradually decreased. This may indicate the existence of a novel osteogenic factor in the gallbladder in HCAO.

Indomethacin activates peroxisome proliferator-activated receptor γ to improve insulin resistance in cotton pellet granuloma model

Inflammation is involved in the development of insulin resistance and diabetes. However, the effectiveness of anti-inflammatory drugs in diabetic therapy remains obscure. In the present study, the possible mechanisms of indomethacin, one of the nonsteroidal anti-inflammatory drugs, in the improvement of insulin resistance were investigated. Indomethacin treatment significantly decreased cotton pellet implantation induced white blood cell count elevation and immune cells infiltration in epididymal white adipose tissue. Also, cotton pellet implantation induced impaired glucose utilization and insulin resistance were improved by indomethacin. The decrement in phosphoinsulin receptor and phospho-Akt levels induced by cotton pellet implantation was improved by indomethacin as well. Moreover, indomethacin decreased cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression in epididymal white adipose tissue with a marked reduction of prostaglandin 2 (PGE2) and nitrite/nitrate (NOx) levels in cotton pellet-implanted mice. Furthermore, pretreatment of peroxisome proliferator-activated receptor γ (PPARγ) antagonist, GW9662 not only reversed indomethacin-modified COX-2 and iNOS levels but also reversed indomethacin-improved insulin sensitivity determined by homeostasis model assessment-insulin resistance (HOMA-IR). Taken together, indomethacin might elevate the expression of PPARγ to decrease serum NOx and PGE2 to result in the improvement of insulin resistance.

Cathepsin-K is a sensitive immunohistochemical marker for detection of micro-granulomas in hypersensitivity pneumonitis

Hypersensitivity Pneumonitis (HP) is an interstitial lung disease that occurs upon exposure to a variety of inhaled organic antigens. The presence of small non-caseating granulomas and isolated giant cells is not specific, but is considered a relevant histological feature for HP. The detection of granulomas is widely considered as easy on standard histological stains, but microgranuloma detection can be difficult and/or time consuming, especially in chronic HP cases. Cathepsin K (Cath-K) is a potent cysteine protease expressed at high levels in activated macrophages (osteoclasts, and epithelioid cells in granulomas), but is not expressed in resident macrophages thus representing a promising marker to rapidly detect and quantitatively evaluate microgranulomas in interstitial lung diseases. We analyzed the expression of Cath-K by immunohistochemistry in 22 subacute and chronic HP cases, using semi-quantitative scores. Control samples included normal lung tissue, and a variety of interstitial lung diseases: 3 Wegener's granulomatosis, 3 sarcoidosis, 3 tuberculosis, 1 berylliosis, 20 idiopathic pulmonary fibrosis (IPF), 2 Langerhans' cell histiocytosis, 5 nonspecific-interstitial pneumonia (NSIP), 5 cryptogenic organising-pneumonia (COP), 2 Airway-Centered Interstitial Fibrosis (ACIF), 5 desquamative interstitial pneumonia (DIP), 3 respiratory bronchiolitis interstitial lung disease (RB-ILD). Intense expression of Cath-K was demonstrated in epithelioid and giant cells in all cases containing granulomas (HP, sarcoidosis, Wegener's granulomatosis, berylliosis, tuberculosis). Among HP cases 19/22 (86.3%) contained granulomas that could be semiquantitatively evaluated. In all HP and control cases alveolar macrophages did not express Cath-K, including cases characterised by large collections of alveolar macrophages such as DIP and RB-ILD.

CONCLUSIONS

Cath-K represents a sensitive and specific marker to detect and quantitate granulomatous reactions in interstitial lung diseases, and is particularly useful in chronic HP cases.

Dealcoholized red and white wines decrease oxidative stress associated with inflammation in rats

In vitroexperiments have demonstrated that polyphenols exhibit antioxidant and anti-inflammatory activities. The present study was designed to test whether dealcoholized red (DRW) and white (DWW) wines can decrease the oxidative stress associated with inflammationin vivo. Rats were fed for 15 d either a control diet or one supplemented with DRW or DWW. Finally, a granuloma was induced by subcutaneous administration of carrageenan. Although DRW showed higher antioxidant activityin vitrothan DWW, both wines decreased the number of cells recruited into the granuloma pouch. Malondialdehyde decreased in plasma and inflammatory exudate from rats fed with DRW- and DWW-rich diets. Moreover, the concentration of NO increased in exudate, which correlates with the increase in the citrulline:arginine ratio. Polymorphonuclear leucocytes from the inflammatory exudate of rats fed dealcoholized wines showed decreased superoxide anion (O2∙−) production and increased NO productionex vivo. This change in NO production resulted from increased expression and activity of inducible NO synthase (EC 1.14.13.39). Moreover, the up regulation of cyclo-oxygenase-2 (EC 1.14.99.1) protein expression observed in rats fed the DRW-rich diet was not related to a direct effect of NO. The present results indicate that the non-alcoholic compounds of wines not only improve antioxidant status in an inflammatory situation, but also limit cell infiltration, possibly through a decrease in O2∙−and an increase in NO production.

Monocyte-Astrocyte Networks Regulate Matrix Metalloproteinase Gene Expression and Secretion in Central Nervous System Tuberculosis In Vitro and In Vivo

CNS tuberculosis (CNS-TB) is the most deadly form of tuberculous disease accounting for 10% of clinical cases. CNS-TB is characterized by extensive tissue destruction, in which matrix metalloproteinases (MMPs) may play a critical role. We investigated the hypothesis that Mycobacterium tuberculosis activates monocyte-astrocyte networks increasing the activity of key MMPs. We examined the expression of all human MMPs and the tissue inhibitors of metalloproteinases (TIMPs) in human astrocytes stimulated by conditioned medium from M. tuberculosis-infected monocytes (CoMTB). Real-time RT-PCR showed that gene expression of MMP-1, -2, -3, -7, and -9 was increased (p < 0.05). MMP-9 secretion was significantly up-regulated at 24 h and increased over 120 h (p < 0.01). MMP-1, -3, and -7 secretion was not detected. Secretion of MMP-2 was constitutive and unaffected by CoMTB. Astrocyte gene expression and secretion of TIMP-1 was not affected by CoMTB although TIMP-2 secretion increased 3-fold at 120 h. Immunohistochemical analysis of human brain biopsies confirmed that astrocyte MMP-9 secretion is a predominant feature in CNS-TB in vivo. Dexamethasone inhibited astrocyte MMP-9, but not TIMP-1/2 secretion in response to CoMTB. CoMTB stimulated the nuclear translocation of NF-kappaB, inducing a 6-fold increase in nuclear p65 and a 2-fold increase in nuclear p50. This was associated with degradation of IkappaBalpha and beta within 30 min, persisting for 24 h. In summary, networks active between monocytes and astrocytes regulate MMP-9 activity in tuberculosis and astrocytes are a major source of MMP-9 in CNS-TB. Astrocytes may contribute to a matrix degrading environment within the CNS and subsequent morbidity and mortality.

Role for matrix metalloproteinase 9 in granuloma formation during pulmonary Mycobacterium tuberculosis infection

Recent studies have shown that matrix metalloproteinases (MMPs) are induced by Mycobacterium tuberculosis during pulmonary infection. Here, expression of MMP-9 during pulmonary M. tuberculosis infection was characterized to determine whether its production correlated with disease resistance in vivo and to determine what role, if any, MMP-9 might have in granuloma formation. Following aerosol infection with M. tuberculosis, dissemination of bacilli occurred earlier in the C57BL/6 resistant mouse strain than in the susceptible CBA/J strain, as was evident from an increased number of bacteria in the blood, spleen, and liver at day 14 after infection. In addition, early dissemination of the bacilli was associated with early induction of protective immunity as assessed from gamma interferon levels. Nonspecific blocking of MMPs in C57BL/6 mice early during infection reduced hematogenous spread of the bacilli, suggesting that MMPs indeed play a role in facilitating dissemination, likely via extracellular matrix degradation. The concentration of active MMP-9, specifically, was greater in the lungs of C57BL/6 mice than in those of the CBA/J mice at day 28, thereby suggesting that MMP-9 is not one of the MMPs directly involved in promoting early dissemination of M. tuberculosis. Instead, however, histological lung sections and flow cytometric analysis of lung cells from MMP-9-knockout mice showed that MMP-9 is involved in macrophage recruitment and granuloma development. These combined data support the idea that early MMP activity is an essential component of resistance to pulmonary mycobacterial infection and that MMP-9, specifically, is required for recruitment of macrophages and tissue remodeling to allow for the formation of tight, well-organized granulomas.

Induction of tumour necrosis factor, interleukin-1beta and matrix metalloproteinases in pulmonary fibrosis of rats infected with Angiostrongylus cantonensis

In angiostrongyliasis, chronic parasite-induced granuloma formation can lead to tissue destruction and fibrosis. Here, the histomorphology of granulomatous fibrosis and proteinase production in the lungs of Angiostrongylus cantonensis-infected Sprague-Dawley rats were investigated. The relationship between metalloproteinases and granulomatous fibrosis was investigated following infection of each rat with 60 infective larvae. Granulomata and fibrosis were marked in the lungs of rats on day 180 post-inoculation. Reverse transcriptase polymerase chain reaction of lung mRNA showed an up-expression of proinflammatory cytokine including tumour necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1beta). According to Western blot analysis, matrix metalloproteinase-2 (MMP-2) proenzyme was presented in the lungs of uninfected and infected rats, and partial conversion of 72 kDa proenzyme to the 64 kDa active form occurred in infected rats. In addition, increased protein levels of MMP-9 and MMP-13 were detected in infected lungs, but were undetectable in controls. The results suggest that TNF-alpha, IL-1beta, MMP-2, -9, and -13 may be associated with the granulomatous fibrosis.

Cyclooxygenase 2 expression in vessels and nerves in reversal reaction leprosy

Tissue expression of cyclooxygenase (COX)2, an inducible enzyme synthesizing eicosanoids in inflammation, was studied in reversal reaction (RR) leprosy in comparison with nonreactionary leprosy. COX2 was consistently expressed in cells of the mononuclear-macrophage lineage across the leprosy spectrum. Only in RR, the following two additional sites showed COX2 expression in the dermis and subcutis: 1) microvessels and 2) nerve bundles and isolated nerve fibers. The same sites also express vascular endothelial growth factor (VEGF). This is in keeping with experimental models relating VEGF to COX2 expression, with VEGF enhancing prostaglandin production through COX2 stimulation and prostaglandin synthase expression. We postulate that selective COX2 inhibitors, which are currently used in several inflammatory conditions, could be considered for RR treatment to reduce acute symptoms caused by tissue edema and possibly prevent long-term nerve damage, the main complication of RR.

Matrix metalloproteinase-2 and -9 in the granulomatous fibrosis of rats infected with Angiostrongylus cantonensis

The histomorphology of granuloma formation and gelatinase production were investigated in the brains, hearts, lungs and livers of Sprague-Dawley rats infected with Angiostrongylus cantonensis. The relationships between two gelatinases and granulomatous fibrosis were explored, following infection of each rat with 60 infective larvae of the nematode. Worm recovery from the brain was maximal on day 15 post-inoculation whereas peak recovery from the lungs was maximal 75 days later, on day 90. The granulomatous reactions and fibrosis were marked in the lungs but only mild, if present at all, in the brain, heart and liver. Gelatin zymography revealed that matrix metalloproteinase2 (MMP-2) was present, at all time-points, in the heart and lungs, although only in the lungs was there partial conversion of the 72-kDa pro-enzyme to the 64-kDa active form during granulomatous fibrosis. The activity of the MMP-9 pro-enzyme was significantly higher at the time-points when granuloma formation was observed than at other times. Immuno-histochemistry revealed MMP-2 and MMP-9 within the lung granulomas, around infiltrating leucocytes and the epithelial cells of the alveoli. As the granulomatous fibrosis appeared to be strongly associated with MMP-2 and MMP-9, these enzymes may be useful markers in the lungs of rats infected with A. cantonensis.

Nitrotyrosine localization to dermal nerves in borderline leprosy

BACKGROUND

Nerve damage is a common and disabling feature of leprosy, with unclear aetiology. It has been reported that the peroxidizing agents of myelin lipids-nitric oxide (NO) and peroxynitrite-are produced in leprosy skin lesions.

OBJECTIVES

To investigate the localization of nitrotyrosine (NT)-a local end-product of peroxynitrite-in leprosy lesions where dermal nerves are affected by a granulomatous reaction.

METHODS

We investigated by immunohistochemistry and immunoelectron microscopy the localization of the inducible NO synthase (iNOS) and NT in biopsies exhibiting dermal nerves from patients with untreated leprosy.

RESULTS

There were abundant NT-positive and iNOS-positive macrophages in the borderline leprosy granulomas infiltrating peripheral nerves identified by light microscopy, S-100 and neurofilament immunostaining. Immunoelectron microscopy showed NT reactivity in neurofilament aggregates and in the cell wall of Mycobacterium leprae.

CONCLUSIONS

Our results suggest that NO and peroxynitrite could be involved in the nerve damage following borderline leprosy.

A case of primary cutaneous CD30+ T-cell lymphoproliferative disorder with features of granulomatous slack skin disease

We present a patient with primary CD30+ cutaneous T-cell lymphoma whose histological and clinical features overlapped with those of granulomatous slack skin disease (GSSD). A 26-year-old woman had infiltrative erythema on the abdominal wall and an incurable ulcerative lesion on the left knee. Her skin progressively became atrophic and pendulous, showing a hyperpigmented appearance over almost the whole body. Histopathologically, a dense lymphoid cell infiltrate accompanying numerous macrophages and multinucleated giant cells (MGC) extended into the subcutaneous tissue. Most lymphoid cells were small and positive for T-cell markers. Some relatively large atypical cells were scattered in the lesion, most of which (60%) were positive for CD30. T-cell receptor-beta gene rearrangement was confirmed in the abdominal lesion. MGC infiltrated more dominantly into a deeeper layer of the skin with the elastic fibres there almost completely disappearing. Immunoreactivity for CD30 of MGC was negative and overexpression of elastolytic metalloproteinases was observed. The association between primary cutaneous CD30+ lym- phoproliferative disorders and GSSD has not previously been reported. Overexpression of elastolytic metalloproteinases in MGC contributes to the disappearance of the elastic fibres and enhances the severity of the clinical course.

Suppression of basic fibroblast growth factor-induced angiogenesis by a specific chymase inhibitor, BCEAB, through the chymase-angiotensin-dependent pathway in hamster sponge granulomas

1. We investigated the profound involvement of mast cell chymase, an alternative angiotensin II-generating enzyme, in angiogenesis using a specific chymase inhibitor. We also studied the functional profiles of this novel inhibitor in basic fibroblast growth factor (bFGF)-induced angiogenesis. 2. In this study, angiogenesis was induced by daily injections of bFGF (0.3 micro g site(-1) day(-1)), angiotensin I (2 nmol site(-1) day(-1)) or angiotensin II (2 nmol site(-1) day(-1)) into sponges implanted to male hamsters subcutaneously for 7 days. Angiogenesis in the granulation tissue surrounding sponges was evaluated by measuring the haemoglobin (Hb) content and local blood flow as the parameters for angiogenesis. 3. A chymase inhibitor, BCEAB (4-[1-[[bis-(4-methyl-phenyl)-methyl]-carbamoyl]-3-(2-ethoxy-benzyl)-4-oxo-azetidine-2-yloxy]-benzoic acid), was simultaneously administered into the implanted sponges (2 or 5 nmol site(-1) day(-1), for 7 days) treated with bFGF and strongly suppressed the haemoglobin contents in sponge granulomas. In the studies using a laser doppler perfusion imager, BCEAB (5 nmol site(-1) day(-1)) also attenuated the bFGF-induced increase of local blood flow around the implanted sponge granuloma. 4. In bFGF-induced angiogenesis, chymase activity in sponge granulomas was substantially increased. It was also confirmed that the chymase activity increased by bFGF was significantly and dose-dependently inhibited by BCEAB (2, 5 nmol site(-1) day(-1)). 5. BCEAB inhibited the Hb contents and the expression of vascular endothelial growth factor (VEGF) mRNA induced by angiotensin I but not by angiotensin II. 6. These results suggest that the significance of chymase in bFGF-induced angiogenesis was confirmed, and a novel inhibitor, BCEAB, strongly suppresses the bFGF-induced angiogenesis through the chymase-angiotensin II-VEGF dependent pathway.

The effect of exogenous peroxidase on the evolution of murine leprosy

Mycobacterium lepraemurium (MLM) is a successful parasite of murine macrophages; in vitro, this microorganism infects macrophages without triggering these cells' ability to produce either the reactive oxygen intermediaries (ROI) or the reactive nitrogen intermediaries (RNI), and ends up lodging within these cells, that, in addition, do not contain myeloperoxidase (MPO). In this study, we analyzed the effect of exogenous peroxidase on the evolution of murine leprosy. Bacilli were intraperitoneally injected, either alone (MLM) or precoated with horseradish peroxidase (MLM-PO), into two different groups of mice. At two-week intervals, the groups were blood-sampled to measure the levels of antibodies to protein- or lipid-MLM antigens. The extent of the disease was also assessed by looking at the histopathologic changes that occurred both in the liver and the spleen of the infected animals. We found that the animals injected with MLM-PO developed a disease that evolved at a slower pace than the disease that occurred in the animals injected with intact MLM. The difference between groups, both in terms of antibody levels and histological changes, was clearly evident at the intermediate stages of the disease (2 to 2.5 months), but was not so obvious at the more advanced stage of 3 months. Several possibilities to explain how the PO-coated bacilli might have regained their infectiousness are discussed. Lowering the infective dose of MLM and MLM-PO from 5 x 10(7) bacilli to 5 x 10(6) bacilli would, probably, have resulted in a different outcome of the disease: more extended in the MLM-group than in the MLM-PO group.

Differential regulation of nitric oxide synthase-2 and arginase-1 by type 1/type 2 cytokines in vivo: granulomatous pathology is shaped by the pattern of L-arginine metabolism

Type 2 cytokines regulate fibrotic liver pathology in mice infected with Schistosoma mansoni. Switching the immune response to a type 1-dominant reaction has proven highly effective at reducing the pathologic response. Activation of NOS-2 is critical, because type 1-deviated/NO synthase 2 (NOS-2)-deficient mice completely fail to control their response. Here, we demonstrate the differential regulation of NOS-2 and arginase type 1 (Arg-1) by type 1/type 2 cytokines in vivo and for the first time show a critical role for arginase in the pathogenesis of schistosomiasis. Using cytokine-deficient mice and two granuloma models, we show that induction of Arg-1 is type 2 cytokine dependent. Schistosome eggs induce Arg-1, while Mycobacterium avium-infected mice develop a dominant NOS-2 response. IFN-gamma suppresses Arg-1 activity, because type 1 polarized IL-4/IL-10-deficient, IL-4/IL-13-deficient, and egg/IL-12-sensitized animals fail to up-regulate Arg-1 following egg exposure. Notably, granuloma size decreases in these type-1-deviated/Arg-1-unresponsive mice, suggesting an important regulatory role for Arg-1 in schistosome egg-induced pathology. To test this hypothesis, we administered difluoromethylornithine to block ornithine-aminodecarboxylase, which uses the product of arginine metabolism, L-ornithine, to generate polyamines. Strikingly, granuloma size and hepatic fibrosis increased in the ornithine-aminodecarboxylase-inhibited mice. Furthermore, we show that type 2 cytokine-stimulated macrophages produce proline under strict arginase control. Together, these data reveal an important regulatory role for the arginase biosynthetic pathway in the regulation of inflammation and demonstrate that differential activation of Arg-1/NOS-2 is a critical determinant in the pathogenesis of granuloma formation.

IL-10 mediates susceptibility to Leishmania donovani infection

Human visceral leishmaniasis (VL) results in a severe and potentially fatal systemic disease, accompanied by cellular immune depression. The production of IL-10 correlates with ongoing disease and it has been suggested that the cellular immune depression that accompanies active disease may be due to a predominance of IL-10 production rather than a lack of IFN-gamma production, which is essential for optimal macrophage activation and parasite elimination. To examine the role of IL-10 in resistance during L. donovani infection (a causative agent of VL), the course of infection was examined in mice lacking the gene for IL-10. BALB/c IL-10-/-, as well as C57BL/6 IL-10-/- mice, were highly resistant to L. donovani infection, as evidenced by liver parasite burdens which were tenfold lower than those in control mice after 14 days of infection. Enhanced resistance was accompanied by increased production of IFN-gamma and nitric oxide in BALB/c IL-10-/- mice. Susceptibility to infection in BALB/c IL-10-/- mice was enhanced following in vivo treatment with a neutralizing antibody to IFN-gamma or IL-12. Together these studies demonstrate for the first time that IL-10 is a critical component of the immune response that inhibits resistance to L. donovani.

T cell-dependent inducible nitric oxide synthase production and ultrastructural morphology in BALB/c mice infected with Mycobacterium avium subspecies paratuberculosis

Euthymic BALB/c and athymic nude BALB/c mice aged 3-8 days were infected intraperitoneally with Mycobacterium avium subspecies paratuberculosis (ATCC strain 19698). After euthanasia at 5 months post-inoculation, hepatic granulomas were evaluated by morphometric analysis of digital images captured from light microscopy sections, by electron microscopy and by immunohistochemical methods. Euthymic mice differed from athymic mice in that (1) their hepatic granulomas were smaller, contained fewer bacteria, and produced more inducible nitric oxide synthase, and (2) their hepatic macrophages contained fewer bacteria, a higher percentage of degraded bacteria, and increased numbers of primary lysosomes. The study showed that macrophage activation was markedly less in the T cell-deficient athymic mice than in the euthymic mice.

Effect of nitric oxide synthase inhibition on Schistosoma japonicum egg-induced granuloma formation in the mouse liver

Nitric oxide (NO) plays diverse roles in a variety of pathological processes. We investigated the role of NO in Schistosoma japonicum egg-induced granuloma formation in a mouse hepatic model. Immunohistological analysis revealed that there is the most intense and extensive inducible nitric oxide (iNOS) expression 2 weeks after egg implantation, and thereafter it decreased considerably with time. Treatment with nitric oxide synthase inhibitors, NIL (L-N6- (iminoethyl)-lysine) or N(omega)-nitro-L-arginine methyl ester (L-NAME), resulted in two different types of unusual granulomas at 2 weeks. One type showed suppressed fibrosis, while another showed foreign body-type multinuclear cell formation which frequently appeared particularly when 50 microg/ml NIL was given. At 3 weeks following treatment, fibrotic granulomas with scanty peripheral cellularity was obvious. However, there were no apparent changes after this period (at 4 weeks). Cytokine analysis in NIL-treated mice showed a significant increase of IL-4 and IL-13 production at 2 weeks. These findings indicated that nitric oxide contributes to granuloma development during the early stages, probably through the regulation of Th2 cytokine production.

Extrarenal expression of 25-hydroxyvitamin d(3)-1 alpha-hydroxylase

The mitochondrial enzyme 25-hydroxyvitamin D(3)-1 alpha-hydroxylase (1 alpha-hydroxylase) plays an important role in calcium homeostasis by catalyzing synthesis of the active form of vitamin D, 1,25-dihydroxyvitamin D(3), in the kidney. However, enzyme activity assays indicate that 1 alpha-hydroxylase is also expressed in a variety of extrarenal tissues; recent cloning of cDNAs for 1 alpha-hydroxylase in different species suggests that a similar gene product is found at both renal and extrarenal sites. Using specific complementary ribonucleic acid probes and antisera to 1 alpha-hydroxylase, we have previously reported the distribution of messenger ribonucleic acid and protein for the enzyme along the mouse and human nephron. Here we describe further immunohistochemical and Western blot analyses that detail for the first time the extrarenal distribution of 1 alpha-hydroxylase in both normal and diseased tissues. Specific staining for 1 alpha-hydroxylase was detected in skin (basal keratinocytes, hair follicles), lymph nodes (granulomata), colon (epithelial cells and parasympathetic ganglia), pancreas (islets), adrenal medulla, brain (cerebellum and cerebral cortex), and placenta (decidual and trophoblastic cells). Further studies using psoriatic skin highlighted overexpression of 1 alpha-hydroxylase throughout the dysregulated stratum spinosum. Increased expression of skin 1alpha-hydroxylase was also associated with sarcoidosis. In lymph nodes and skin from these patients 1 alpha-hydroxylase expression was observed in cells positive for the surface antigen CD68 (macrophages). The data presented here confirm the presence of protein for 1 alpha-hydroxylase in several extrarenal tissues, such as skin, placenta, and lymph nodes. The function of this enzyme at novel extrarenal sites, such as adrenal medulla, brain, pancreas, and colon, remains to be determined. However, the discrete patterns of staining in these tissues emphasizes a possible role for 1 alpha-hydroxylase as an intracrine modulator of vitamin D function in peripheral tissues.

IL-4 plays a crucial role in regulating oxidative damage in the liver during schistosomiasis

Liver enlargement and hepatocyte proliferation, normal responses in wild-type (WT) mice infected with the parasitic helminth Schistosoma mansoni, were found to be severely impaired in infected IL-4(-/-) mice. Compared with WT mice, increased levels of O(2)(-), NO, and the more highly reactive ONOO(-) were detected in the liver and produced by lesional cells isolated from liver granulomas of infected IL-4(-/-) mice. Concurrently, antioxidant defenses in the liver, specifically catalase levels, diminished dramatically during the course of infection in these animals. This contrasted to the situation in infected WT mice, where catalase levels remained as high as those in normal mice. Actual levels of reactive oxygen and nitrogen intermediates in the livers of infected IL-4(-/-) animals are thus likely to be considerably higher than those in the livers of infected WT mice. To determine whether these changes contributed to the development of the more severe disease that characterizes infection in the IL-4(-/-) animals, we treated infected IL-4(-/-) mice with uric acid, a potent scavenger of ONOO(-). This resulted in significantly increased hepatocyte proliferation, decreased morbidity, and prolonged survival. Taken together, these data indicate that IL-4 is playing a protective role during schistosomiasis by controlling the tight regulation of the generation of reactive oxygen and nitrogen intermediates in the liver.

Cyclooxygenase expression in the gallbladder

The COX expressions were evaluated separately in the epithelium and in the stroma of gallbladder cancer, chronic cholecystitis, xanthogranulomatous cholecystitis (XGC) and the normal gallbladder. In normal gallbladder COX-2 expression rate was significantly higher in the epithelium than in the stroma. The COX-2 expression rate in the epithelium of non-cancerous adjacent epithelium to cancerous lesion was significantly lower than those not only of cancer, but also chronic cholecystitis, XGC and normal gallbladder. In stroma, the COX-2 expression rate in cancer, chronic cholecystitis and XGC were significantly higher than that of the normal gallbladder. The rate in non-cancerous adjacent stroma to cancer is significantly lower than that of cancer and XGC. However, the difference of rate between of normal and of chronic cholecystitis was not significant. The COX-2 expression rates were significantly higher in both the epithelium and the stroma in the well and moderately differentiated cancer group than in the poorly and undifferentiated cancer group. Our results suggest that COX-2 expression in the gallbladder may be regulated by various factors and not directly related to carcinogenesis. The significance of its repression in the non-cancerous adjacent tissue to cancer lesion should be re-evaluated.

Expression of the proteinase specialized in bone resorption, cathepsin K, in granulomatous inflammation

BACKGROUND

The cysteine proteinase cathepsin K has aroused intense interest as the main effector in the digestion of extracellular matrix during bone resorption by osteoclasts. The enzyme is not a housekeeping lysosomal hydrolase, but is instead expressed with striking specificity in osteoclasts. In this work, we present evidence for the association of cathepsin K with the granulomatous reaction. Granulomas are inflammatory tissue reactions against persistent pathogens or foreign bodies. We came across cathepsin K while working on Echinococcus granulosus, a persistent tissue-dwelling, cyst-forming parasite that elicits a granulomatous response.

MATERIALS AND METHODS

The walls of hydatid cysts from infected cattle were solubilized. Strong proteolytic activity was detected in the extracts. The proteinase responsible was purified by anion exchange and gel filtration. The purified protein was subjected to N-terminal sequencing, and its identity further confirmed by Western blotting, with a cathepsin K-specific antibody. The same antibody was used to localize the proteinase in paraffin-embedded sections of the parasite and the local host response.

RESULTS

A proteinase was purified to near homogeneity from hydatid cyst extracts. The enzyme was unequivocally identified as host cathepsin K. Both the proenzyme and the mature enzyme forms were found. Cathepsin K was then immunolocalized both to the parasite cyst wall and to the epithelioid and giant multinucleated cells of the host granulomatous response.

CONCLUSIONS

In the granulomatous response to the hydatid cyst, cathepsin K is expressed by epithelioid and giant multinucleated cells. We propose that, by analogy with bone resorption, cathepsin K is secreted by the host in an attempt to digest the persistent foreign body. Both processes, bone resorption and granulomatous reactions, therefore tackle persistent extracellular material (the bone matrix or the foreign body), and utilize specialized cells of the monocytic lineage (osteoclasts or epithelioid/giant cells) secreting cathepsin K as an effector.

Purification and characterization of a secretory serine proteinase of Acanthamoeba healyi isolated from GAE

We purified and characterized a serine proteinase secreted by Acanthamoeba healyi to evaluate it as a possible virulence factor in the pathogenesis of granulomatous amoebic encephalitis (GAE). Ammonium sulfate precipitated culture supernatant of A. healyi OC-3A strain was purified by chromatography on CM-Sepharose, Sephacryl-S200, and Q-2 anion-exchange columns. The purified 33-kDa enzyme had a pH optimum of 8.0 and a temperature optimum of 40 C. Phenylmethylsulfonylfluoride and diisopropyl fluorophosphate, serine proteinase inhibitors, diminished activity of the enzyme to near zero. In addition to types I and IV collagen and fibronectin, the main components of the extracellular matrix, other proteins such as fibrinogen, IgG, IgA, albumin, and hemoglobin were also degraded by the enzyme. The broad substrate specificity of this secreted serine proteinase suggests that it may play an important role in pathogenesis of GAE by A. healyi.

In situ detection of human monocyte/macrophage serine esterase-1 mRNA expression in human tissues

Human monocyte/macrophage serine esterase (HMSE) can be distinguished from esterases of other blood cells by a specific isoelectric focusing pattern of five enzyme variants. Using a HMSE-1 cDNA, expression of mRNA was investigated by nonradioactive in situ hybridization of human biopsy specimens and cytospin preparations. HMSE-1 transcripts could be detected in the myelomonocytic cell line U-937, blood monocytes and in tissue macrophages. Immune accessory cells of the monocyte/macrophage lineage did not express detectable amounts of HMSE-1 mRNA. These results indicate that HMSE-1 represents a cell-lineage-specific enzyme which can be used to characterize physiological and neoplastic variants of the human monocyte/macrophage cell system. The method described will enable further insight into the physiological function of HMSE-1.

Expression of inducible nitric oxide synthase in human granulomas and histiocytic reactions

Inducible nitric oxide synthase (iNOS) is required in immune response against infections and is involved in granuloma formation in animals; in murine macrophages, iNOS is induced by lipopolysaccharide and interferon-gamma. In contrast, the role of iNOS in human immune response against infections is still questioned, and its expression in granulomas is poorly investigated. Using Western blotting and immunohistochemistry, we investigated iNOS expression in human lymph nodes with nonspecific reactions and in tissues containing granulomas caused by mycobacteria, Toxoplasma, Cryptococcus neoformans, Leishmania, Bartonella, noninfectious granulomas (sarcoidosis, foreign body), and other hystiocitic reactions (Kikuchi's disease, Omenn syndrome). iNOS was undetectable in nonspecific reactive lymphadenitis, foreign-body granulomas, and Omenn syndrome, whereas it was strongly expressed in infectious granulomas, sarcoidosis, and Kikuchi's diseases. Immunohistochemistry demonstrated that iNOS was selectively expressed by the epithelioid and multinucleated giant cells within the granulomas. Use of an anti-nitrotyrosine antibody, recognizing nitrosilated amino acid residues derived from nitric oxide production, revealed a consistent positivity within the cells expressing iNOS, thus suggesting that iNOS is functionally active. Detection of cytokines by reverse transcriptase-polymerase chain reaction demonstrated that tissues that were positive for iNOS, also expressed the Thl-type cytokine interferon-gamma mRNA, but not the Th2-type cytokine interleukin-4. Taken together, these results indicate that iNOS is involved in different human immune reactions characterized by histiocytic/granulomatous inflammation and associated with Th1-type cytokine secretion.

Localization and secretion of tissue kallikrein in peptidoglycan-induced enterocolitis in Lewis rats

The plasma kallikrein-kinin system is a mediator of intestinal inflammation induced by peptidoglycan-polysaccharide from group A streptococci (PG-APS) in rats. In this study we investigated the participation of intestinal tissue kallikrein (ITK). Lewis rats were injected intramurally with PG-APS. ITK was visualized by immunohistochemical staining. Cecal ITK concentration was measured by radioimmunoassay, and gene expression was evaluated by RNase protection assay. Kallikrein-binding protein (KBP) was evaluated in plasma by ELISA. Tissue kallikrein was identified in cecal goblet cells in both control and PG-APS-injected rats and in macrophages forming granulomas in inflamed tissues. Cecal ITK was significantly lower in acute and chronic phases of inflammation and in supernatant from in vitro cultures of inflamed cecum. ITK mRNA levels were not significantly different. Plasma KBP levels were significantly reduced in inflamed rats. The presence of tissue kallikrein in macrophages suggests participation in experimental colitis. The decrease of ITK in the inflamed intestine associated with unchanged mRNA levels suggests ITK release during intestinal inflammation.

Mechanisms of the anti-inflammatory activity of low-dose radiation therapy

PURPOSE

To investigate the hypothesis that modulation of the function of activated macrophages is one of the mechanisms of the clinically observed anti-inflammatory and analgesic efficacy of low-dose radiotherapy in the treatment of a variety of painful joint diseases with total doses between 1 and 6 Gy.

MATERIALS AND METHODS

Metabolic activity, cell proliferation, reproductive integrity, nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression by unstimulated or [LPS/gamma-IFN-stimulated macrophages in vitro was investigated at different times after radiation doses ranging from 0.3 Gy to 10 Gy. In vivo, chronic granulomatous air pouches were induced in mice and either sham treated or irradiated with 2 Gy on day 2 or day 6, or with five daily doses of 0.5 Gy. On day 7, the iNOS expression was assessed by Western blot and localized by immuno-histochemistry in cryostat sections.

RESULTS

In stimulated macrophages, metabolic activity, proliferation and reproductive integrity were not affected by radiation doses up to 10 Gy since they are apparently irreversible post-mitotic cells. However, a dose-dependent modulation of the NO pathway was observed with significant inhibition by the low radiation doses used in anti-inflammatory radiotherapy but with super-stimulation by the high radiation doses used in cancer therapy.

CONCLUSIONS

The empirically based anti-inflammatory radiotherapy of benign diseases appears to act through specific modulation of different pathways of inflammatory reactions such as the nitric oxide pathway in stimulated macrophages.

The involvement of matrix metalloproteinases and inflammation in lumbar disc herniation

STUDY DESIGN

Surgically obtained herniated lumbar disc specimens were stained with hematoxylin-eosin or toluidine blue (for detection of proteoglycans) or were immunostained with monoclonal antibodies (CD68), antihuman interstitial collagenase (matrix metalloproteinase [MMP]-1) and antihuman stromelysin (MMP-3).

OBJECTIVE

To investigate the possible correlation of matrix metalloproteinase activity to granulation tissue formation and lumbar disc herniation, depending on the type of herniation.

SUMMARY OF BACKGROUND DATA

Interstitial collagenase and stromelysin have been implicated in the degradation of the matrix of articular cartilage in rheumatoid arthritis, osteoarthritis and degenerated disc tissues. However, their role in the herniation of the intervertebral disc has received little study.

METHODS

Twenty-one specimens of lumbar disc herniation (classified as protrusions, subligamentous extrusions, transligamentous extrusions, and sequestrations) and four nonherniated discs were stained with hematoxylin-eosin or toluidine blue or were immunostained with monoclonal antibodies to CD20, CD45RO, and CD68, anti-MMP-1, and anti-MMP-3, using the avidin-biotin-peroxidase complex method. The amount of granulation tissue and results of staining were graded to examine differences in histology among the four herniation types.

RESULTS

In sequestration and transligamentous extrusion specimens, granulation tissue containing many CD68-positive macrophages was commonly observed. Most cells in granulation tissue, as well as chondrocytes, stained positively with anti-MMP-1 and anti-MMP-3 antibodies. Granulation tissue was less commonly observed in subligamentous extrusions and was absent from most protrusion specimens and all nonherniated specimens. B and T lymphocytes could not be demonstrated in granulation tissue.

CONCLUSIONS

The increased staining of MMP-1 and MMP-3 associated with inflammatory cells of granulation tissue in herniated discs suggests a causal correlation of these proteinases to tissue degradation in herniation.

Vasectomy-induced superoxide dismutase inactivation in the male reproductive tract of rat: a prerequisite for spermatic granuloma formation

Post vasectomy spermatic granuloma formation is considered as a favourable development for vasectomized subjects as it maintains physiological hydrostatic pressure within the male reproductive tract. But, the 'state of the art' of the formation of granuloma after vasectomy is not well defined. The present study reveals a link between the postvasectomy free radical status of the male tract and spermatic granuloma formation after vasectomy. A surge in the rate of ascorbyl radical production, directly correlated with oxyradical stress and an abrupt fall in superoxide dismutase activity in the granuloma, indicates 'switching on' of a free radical-dependent machinery for the formation of granuloma after vasectomy.

First case of surgical treatment of Farber's disease

Farber's disease (Farber's lipogranulomatosis), which is inherited as an autosomal recessive trait, was first reported by Farber in 1952. We report a case of Farber's disease in a 12-year-old female. Her younger brother was affected with Farber's disease and died of it at 2 years of age. When she first presented, our patient's main clinical features were a shrill voice; subcutaneous nodules; contracture of the joints throughout the body; and granulomas of the oral cavity, the pharynx, and the upper and lower eyelids. Serial radiographs disclosed deformation of the joints throughout the body. Due to the granulomas in her oral cavity, she could take little food orally and therefore was malnourished. We performed a granulectomy under general anesthesia, and her difficulty with feeding and upper airway obstruction improved. There is no specific treatment for Farber's disease, and most patients reported have died by 2 years of age. This is the first reported patient with Farber's disease who has been surgically treated.

Expression of inducible nitric oxide synthase and its involvement in pulmonary granulomatous inflammation in rats

Two types of pulmonary granulomatosis were produced in rats by intratracheal instillation of zymosan or silica. In both models, immunostaining with anti-rat monoclonal antibody for inducible nitric oxide synthase (iNOS), ANOS11, showed that the intensity of iNOS immunoreactivity in the inflammatory lesions peaked at 3 days and declined thereafter. Immunohistochemical double staining and in situ hybridization demonstrated the expression of iNOS in neutrophils, monocyte-derived macrophages, and bronchiolar epithelial cells in the pulmonary lesions. Electron spin resonance spectroscopy revealed the production of an excessive amount of nitric oxide (NO) in the pulmonary lesions. Immunostaining with a polyclonal antibody against nitrotyrosine indicated the formation of nitrotyrosine residues in the granulomatous lesions, particularly in the periphery of the lesions, providing indirect evidence for the generation of peroxynitrite anion in the zymosan- or silica-instilled lungs. Administration of N omega-nitro-L-arginine methyl ester or S-methylisothiourea sulfate, which significantly suppressed NO production, resulted in marked reduction of monocyte/macrophage infiltration as well as in inhibition of induction of monocyte chemoattractant protein-1 in the lesions. These data indicate that NO and its more reactive product peroxynitrite anion may be important mediators of granuloma formation in the lung.

Expression of inducible nitric oxide synthase in rat pulmonary Cryptococcus neoformans granulomas

Rats, like humans, have extremely effective immune mechanisms for controlling pulmonary Cryptococcus neoformans infection. The mechanism(s) responsible for efficient immunity in rat experimental infection is unknown. Recently, induction of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) have been implicated as an important microbicidal mechanism by which activated macrophages effect cytotoxicity against microbes. In this report, we investigated the expression of iNOS in rat pulmonary cryptococcosis. Localization and regulation of NO production was studied by immunohistochemistry for iNOS in conjunction with immunohistochemistry for cell markers, cytokines, and cryptococcal capsular polysaccharide. iNOS immunoreactivity was detected in macrophages, neutrophils, vascular endothelium, and respiratory epithelium. Double-immunolabeling studies revealed that the most prominent iNOS immunoreactivity was localized to epithelioid macrophages (CD11b/c+) within granulomas; CD4+ and CD8+ T cells were numerous around granulomas but did not express iNOS. iNOS immunoreactivity was detected in a selective population of epithelioid macrophages within some granulomas but not others. iNOS- granulomas were identical to iNOS+ granulomas with respect to morphology and immunohistochemical profiles. Macrophage iNOS immunoreactivity was detected 1 week after infection in one out of four rats and was strongly expressed in all rats at 2 weeks (in up to 50 percent of the granulomas) but declined considerably by 25 days. iNOS expression coincided with granuloma formation and preceded a decrease in lung fungal burden, suggesting an anticryptococcal role for NO. By double labeling, cytokines that have been shown to promote (interferon-gamma, granulocyte/macrophage colony-stimulating factor) and inhibit (transforming growth factor-beta) macrophage iNOS expression were detected around iNOS+ granuloma. iNOS immunoreactivity was expressed in selected neutrophils (1 and 2 weeks) and endothelial cells (1 and 2 weeks and 25 days) in the inflamed lung. Airway iNOS immunoreactivity was limited to the luminal border of rare bronchiolar epithelial cells. iNOS immunoreactivity was not detected in uninfected rats. The present study provides the first evidence for association of iNOS expression with protective cellular responses to cryptococcal infection in vivo.

Intravascular granuloma induced by intravenous inoculation of Cryptococcus neoformans

In rodents an intravenous administration of viable Cryptococcus (C.) neoformans cells frequently resulted in attachment of intravascular cryptococcal granulomas to inner walls of the large to medium-sized veins of various organs, including the lungs, liver and spleen. In order to elucidate the pathogenesis of granulomatous changes, the cells composing the intravascular granulomas were observed by electron microscopic peroxidase (PO) cytochemistry. The granuloma composing cells could be divided into the following four types according to the pattern of endogenous peroxidase activity: exudate macrophage (M phi, type I), PO-negative M phi (type II), resident M phi (type III) and other inflammatory cells (type IV). In the intravenous granulomas of the lung, the percentages of composed cells were 39.0% for type I, 57.9% for type II, 0% for type III and 3.1% for type IV. By contrast, in the interstitial granulomas in the lung, type III M phi s, possibly derived from alveolar M phi s, played a significant role in granuloma formation. This may indicate that the intravascular granuloma is almost composed of macrophages derived from monocytes rather than alveolar macrophages. The expression of ICAM-1 on endothelia of the pulmonary veins was examined by immunoelectron microscopy. An immunogold labeling index was significantly augmented on the surface of endothelia in response to intravenous challenge of C. neoformans. The intravascular granuloma demonstrates that the monocytes develop into the granuloma-composing macrophages and suppress the cryptococcal activities even in the peripheral blood resulting in an assistance of endothelial functions.

Distribution of cyclooxygenase isoforms in murine chronic granulomatous inflammation. Implications for future anti-inflammatory therapy

Inhibition of the enzyme cyclooxygenase (COX) is the basis for the mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs). COX exists as a constitutive (COX-1) and a mitogen-inducible (COX-2) isoform. The relative contribution of COX-1 and COX-2 to inflammation is unknown. This study investigated COX activity and the distribution of COX-1 and COX-2 during the development of a murine air pouch model of chronic granulomatous inflammation. COX activity progressively rose and was maximal at day 14. Of the COX metabolites measured, PGE2 was the greatest > 6-keto PGF1a > TXB2 > PGF2a. By day 7, COX-2-labelled fibroblast- and macrophage-like cells were observed and their number and distribution increased with time. At all time points, endothelial cells of venules in the loose connective tissue of the dermis showed immunoreactivity for COX-2. After day 14, labelling of capillaries in the granuloma was also observed. This study is the first to show that COX-2 is the predominant COX isoform in all stages of the inflammatory response. These results suggest that selective inhibition of COX-2 may prove more beneficial, with fewer gastric and renal side-effects, than existing NSAID therapy for the treatment of chronic inflammatory diseases.

Effect of carrageenan-induced granuloma on hepatic cytochrome P-450 isozymes in rats

Carrageenan-induced granuloma was used to study the apoprotein and RNA content, and catalytic activities of several cytochrome P-450 isozymes in liver. This model allowed discrimination between acute and chronic phases of experimental inflammation. The expression of most isozymes studied (CYP2D, CYP2E1, CYP3A1 and CYP4A) was reduced to 20% of the control level during the acute phase and partially recovered (30-60% of control group) during the chronic phase. CYP2B1 content was decreased to 65% of control during the acute and chronic phases of inflammation. RNA (CYP2B1 and CYP2E1) showed a strong depression during the acute phase and recovered during the chronic phase, without differences between isoenzymes. In most cases, there was a good correlation between the apoprotein content of isozymes and related activities. Our results show that the depletion of cytochrome P-450 induced by inflammation depends on the severity of the disease. Experimental inflammation equally affect the transcription of CYP2B1 and CYP2E1, so differences in apoprotein content and related activities between isozymes may due to differential posttranscriptional regulation.

Serum angiotensin-converting enzyme activity, concentration, and specific activity in granulomatous interstitial lung disease, tuberculosis, and COPD

Angiotensin-converting enzyme (ACE) activity in serum is used as an aid to the diagnosis and follow-up of patients with sarcoidosis. A theoretical limitation of measurements of activity is that these may be affected by the presence of pharmacologic or endogenous inhibitors of ACE. Immunoassays of ACE concentration avoid this problem and, when combined with tests of ACE activity, permit calculation of specific activity of ACE. In this study, we set out to develop a sensitive radioimmunoassay for ACE to compare results obtained with this method with results of ACE activity and calculated ACE specific activity in patients suffering from a variety of lung diseases. In a group of control subjects (n = 32), the ACE concentration was 453.7 +/- 159.8 (SD) ng/mL; 95% confidence interval (CI), 398.34 to 509.06, but levels were significantly elevated in sarcoidosis (979.3 +/- 558.6 ng/mL; 95% CI, 827.5 to 1,131.1; n = 51; p < 0.001 vs control subjects), silicosis (646.5 +/- 239.1 ng/mL; 95% CI, 544.2 to 748.8; n = 21; p < 0.01), and miliary tuberculosis (647.0 +/- 217.1 ng/mL; 95% CI, 551.9 to 742.1; n = 29; p < 0.01). The levels were normal in COPD, interstitial pulmonary fibrosis, and active cavitary pulmonary tuberculosis. The overall correlation between ACE activity and concentration measurements was strong (r = 0.93). No evidence of endogenous ACE inhibition was observed in any of the disease categories studied except in COPD where an elevation of ACE specific activity was observed, raising the possibility that in this condition different isozymes of ACE with higher specific activity might be released.

NADPH diaphorase staining suggests a transient and localized contribution of nitric oxide to host defence against an intracellular pathogen in situ

Nitric oxide (NO) is formed constitutively in neurons by the constitutive enzyme NO synthase (cNOS) and acts as a neurotransmitter. It has already been shown that cNOS-containing neurons are identical to neurons staining for NADPH diaphorase and vice versa. Effector cells of the immune response produce high NO levels after appropriate stimulation and this NO is formed by inducible NO synthase (iNOS). The NO produced by macrophages is considered an important effector molecule of antimicrobial host defence. We have applied NADPH diaphorase staining for the detection of NO producing cells in situ during infection with an intracellular pathogen. Macrophages which produce NO in vitro are stained for NADPH diaphorase. Expression of iNOS mRNA and macrophage NADPH diaphorase staining was inhibited by iNOS-specific antisense oligonucleotides. These data suggest coincidental similarity between NADPH diaphorase activity and NO production by macrophages. Cells staining for NADPH diaphorase were identified in cryostat frozen sections of livers from mice infected with the intracellular pathogen, Listeria monocytogenes, and co-localized with cells labelled by MAC-1 mAbs. The purple-blue reaction product of NADPH diaphorase staining was visible in discrete granulomatous lesions but was absent from the liver parenchyma. Our results provide direct evidence for localized and transient participation of NO in antimicrobial immunity in the infected organ. This restriction may focus NO production to lesions, leaving unrelated tissue sites unaffected.

Inhibition of a model of in vitro granuloma formation by tetracyclines and ciprofloxacin. Involvement of protein kinase C

BACKGROUND AND DESIGN

Granulomatous inflammation is a common component of many diseases. In this study the ability of commonly used antibiotics to inhibit an in vitro model of granuloma formation were studied. The effect of protein kinase C inhibition in this system was also investigated.

RESULTS

Ampicillin, cephalothin, metronidazole, rifampin, isoniazide, erythromycin, and clindamycin were inactive in inhibiting granuloma formation. Tetracycline, doxycycline, minocycline, and ciprofloxacin produced dose-dependent inhibition of the granuloma model in concentrations between 10(-4) and 10(-6) mol/L. The approximate order of descending potency was doxycycline equals minocycline greater than tetracycline greater than ciprofloxacin. The same drugs were tested for the ability to inhibit protein kinase C. Drugs inactive in the granuloma model had no effect on protein kinase C activity. The tetracyclines and ciprofloxacin all caused a dose-dependent inhibition of protein kinase C activity in the same order of relative potency as was found for inhibition of granuloma formation.

CONCLUSIONS

These data demonstrate a previously unappreciated activity of the tetracyclines and ciprofloxacin. Inhibition of granuloma formation helps to account for the activity of these drugs in the severest forms of inflammatory acne.

A patient with hepatic granuloma formation and angiotensin-converting enzyme production by granuloma cells during clinical relapse of hepatitis A

Elevation of the serum angiotensin-converting enzyme (sACE) level and hepatic granulomas were found during a clinical relapse in a 22 year old patient with acute viral hepatitis type A (AVH-A). The serum transaminase level and sACE level remained high for more than 6 months. In the biopsied specimen of the liver, fibrous rings of granulomas composed of collagen types I, III, and V were observed. Furthermore, the localization of ACE was visible in the rough endoplasmic reticulum of epithelioid cells of granulomas in the liver under electron microscopy using the indirect immunoperoxidase method. These results suggest that granuloma cells in the liver caused by hepatitis A may be involved in ACE production. In addition, other diseases associated with the presence of granulomas in the liver, such as lymphoma, cytomegalovirus infection, visceral leishmaniasis, and lupoid hepatitis, were ruled out. However, the hepatic granulomas disappeared with the healing of AVH-A. In this regard, the present case is considered to be one of the very few cases of hepatic sarcoidosis.

Inducible isoforms of cyclooxygenase and nitric-oxide synthase in inflammation

Cyclooxygenase (COX) converts arachidonic acid to prostaglandin H2, which is further metabolized to prostanoids. Two isoforms of COX exist: a constitutive (COX-1) and an inducible (COX-2) enzyme. Nitric oxide is derived from L-arginine by isoforms of nitric-oxide synthase (NOS; EC 1.14.13.39): constitutive (cNOS; calcium-dependent) and inducible (iNOS; calcium-independent). Here we have investigated inducible isoforms of COX and NOS in the acute, chronic, and resolving stages of a murine air pouch model of granulomatous inflammation. COX and NOS activities were measured in skin samples in the acute phase, up to 24 h. Activities in granulomatous tissue were measured at 3, 5, 7, 14, and 21 days for the chronic and resolving stages of inflammation. COX-1 and COX-2 proteins were assessed by Western blot. COX activity in the skin increased over the first 24 h and continued to rise up to day 14. COX-2 protein rose progressively, also peaking at day 14. COX-1 protein remained unaltered throughout. The iNOS activity increased over the first 24 h in the skin, with a further major increase in the granulomatous tissue between days 3 and 7, followed by a decrease at day 14 and a further increase at day 21. The rise in COX and NOS activities in the skin during the acute phase reinforces the proinflammatory role for prostanoids and suggests one also for nitric oxide. However, in the chronic and resolving stages, a dissociation of COX and NOS activity occurred. Thus, there may be differential regulation of these enzymes, perhaps due to the changing pattern of cytokines during the inflammatory response.

Amounts of angiotensin-converting enzyme mRNA reflect the burden of granulomas in granulomatous lung disease

A number of granulomatous lung diseases, including sarcoidosis, are associated with an increase in angiotensin-converting enzyme (ACE) activity. To evaluate whether the amount of ACE activity reflects the burden of granulomas, we used an animal model of granulomatous lung disease caused by injecting killed Mycobacterium butyricum intravenously into mice after a primary intracutaneous injection with Freund's complete adjuvant. In this model, essentially all of the granulomas are present in the lung. RNA was isolated from one lung and assayed for ACE mRNA. The other lung was evaluated histologically; the area of lung occupied by granulomas was determined by morphometry. We found that total lung RNA and RNA specific for ACE increased in close correlation with the area of granulomas. These findings provide direct evidence that the amount of ACE activity in granulomatous disease reflects the total burden of granulomas. This may be a useful model to further evaluate ACE regulation in granulomatous lung disease.

Monocyte 1 alpha-hydroxylase regulation: induction by inflammatory cytokines and suppression by dexamethasone and uremia toxin

Alveolar macrophages acquire 1 alpha-hydroxylase activity in inflammation, and thereby metabolize 25 hydroxyvitamin D3 (25 D3) to the active metabolite, 1 alpha,25-dihydroxyvitamin D3 (1,25 D3, calcitriol). Calcitriol is a potent differentiation agent that modulates mononuclear phagocyte activation and effector functions. The mediators that induce macrophage 1 alpha-hydroxylase activity are not well delineated. Furthermore, it is unclear whether calcitriol is a product only of terminally differentiated macrophages or whether less mature mononuclear phagocytes can produce it as well. The ability of newly recruited monocytes to produce calcitriol as an autocrine differentiation agent is particularly important in inflammation, as it may substantially expand the functional repertoire of these cells. To assess the effects of cytokines on 1 alpha-hydroxylase activity, blood monocytes were cultured in the presence and absence of human recombinant tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukins 1 and 2 and then incubated with 25 D3 substrate. The conditioned media were assayed for calcitriol by high-performance liquid chromatography and competitive receptor binding assay. No detectable calcitriol was produced by unstimulated monocytes. However, all the cytokines markedly increased monocyte calcitriol production (range 133-151 pg/mg protein; in all cases P < .001). We then determined whether calcitriol production was suppressed by preincubation with either dexamethasone or the putative uremia toxin guanidinosuccinic acid (GSA). Dexamethasone pretreatment significantly inhibited subsequent cytokine-induced calcitriol production by monocytes, as did GSA (average 69 and 63% of control, respectively).

Human recombinant interleukin-1 receptor antagonist (hrIL-1RA) inhibits prostaglandin E2 (PGE2) generation but not alkaline phosphatase activity in in vivo chronic granulomatous tissue induced by KMnO4

Interleukin-1, a soluble polypeptide, plays an important role in inflammatory reactions by increasing prostaglandin E2 (PGE2) generation. Human recombinant IL-1 receptor antagonist (hrIL-1ra) is a natural inhibitor of IL-1 which blocks its activity in several inflammatory states. In these studies we found that hrIL-1ra (250 mg/ml) inhibits the generation of PGE2, as measured by RIA method, in minced mouse granuloma tissue (700 mg) treated overnight with LPS (10-1000 ng/ml) or hrIL-1 beta (0.1-10 ng/ml). In addition, we show that hrIL-1ra (250 ng/ml) strongly inhibited IL-1 alpha and IL-1 beta, as measured by ELISA method, in the minced granuloma tissue treated overnight with LPS 1 micrograms/ml or IL-1 beta (10 ng/ml). The granuloma tissue induced in mice by a dorsal subcutaneous injection (0.2 ml) of a saturated solution (1:40 dilution) of KMnO4 crystals, presented an alkaline phosphatase activity which was not inhibited by two intraperitoneal administrations of hrIL-1ra 20 micrograms/200 ml bolus injections (given at the same time as KMnO4 injection and one 24 h later). These results show for the first time that hrIL-1ra blocks PGE2, IL-1 alpha and IL-1 beta but not alkaline phosphatase activity, which is a marker in growing bone and in calcific and inflamed tissue.

Alpha-naphthyl acetate esterase-1 (ANAE-1) secreted by epithelioid cells from induced rabbit lung granuloma showed MIF activity

The function of alpha-naphthyl acetate esterase-1, whose isoelectric point values range from 5.15 to 5.45, was examined. A higher value of alpha-naphthyl acetate esterase-1 was detected in the extracts of epithelioid cells isolated from rabbit lung granuloma at 4 weeks after injection of Freund's complete adjuvant, compared to those values of alveolar macrophages isolated from the same lungs described above and of the normal lungs. Additionally, this enzyme activity was observed to be prominent in the culture supernatants of epithelioid cells. alpha-Naphthyl acetate esterase-1 was purified from lung granuloma as a single 62-kDa band by SDS-PAGE analysis. The purified enzyme showed a macrophage migration inhibition activity at concentrations over 20 nM, and its activity was dose-dependent. Moreover, when various amounts of the purified enzyme were added to lymphocyte-derived macrophage migration inhibitory factor, macrophage migration inhibition was significantly enhanced with a dose-dependent manner. The results suggest that alpha-naphthyl acetate esterase-1 secreted by granuloma macrophages, particularly by epithelioid cells, contributes to granuloma formation.