Prognostic significance of PI-RADS 5 lesions in patients treated by radical prostatectomy.

PURPOSE: To analyse the pathological features and survival of patients with a PI-RADS 5 lesion on pre-biopsy MRI. METHODS: We extracted from a European multicentre prospectively gathered database the data of patients with a PI-RADS 5 lesion on pre-biopsy MRI, diagnosed using both systematic and targeted biopsies and subsequently treated by radical prostatectomy. The Kaplan-Meier model was used to assess the biochemical-free survival of the whole cohort and univariable and multivariable Cox models were set up to study factors associated with survival. RESULTS: Between 2013 and 2019, 539 consecutive patients with a PI-RADS 5 lesion on pre-biopsy MRI were treated by radical prostatectomy and included in the analysis. Follow-up data were available for 448 patients. Radical prostatectomy and lymph node dissection specimens showed non-organ confined disease in 297/539 (55%), (including 2 patients with a locally staged pT2 lesion and lymph node involvement (LNI)). With a median follow-up of 25 months (12-39), the median biochemical recurrence-free survival was 54% at 2 years (95% CI 45-61) and 28% at 5 years (95% CI 18-39). Among the factors studied, MRI T stage [T3a vs T2 HR 3.57 (95%CI 1.78-7.16); T3b vs T2 HR 6.17 (95% CI 2.99-12.72)] and PSA density (HR 4.47 95% CI 1.55-12.89) were significantly associated with a higher risk of biochemical recurrence in multivariable analysis. CONCLUSION: Patients with a PI-RADS 5 lesion on pre-biopsy MRI have a high risk of early biochemical recurrence after radical prostatectomy. MRI T stage and PSA density can be used to improve patient selection and counselling.

Platelet-rich fibrin (PRF): an autologous packing material for middle ear microsurgery.

OBJECTIVES: To assess the use of PRF prepared using an optimised protocol in middle ear surgery as a substitute for conventional packing products of animal origin such as collagen derived from porcine skin. METHODOLOGY: A retrospective study of 108 patients in whom optimised PRF was used exclusively to pack the external auditory canal or middle ear. The effectiveness or harmlessness of the PRF was evaluated by assessing a range of parameters. A morphological comparison was also made of PRF produced using the Choukroun procedure and our procedure. RESULTS: The success rate of the repair of the tympanic membrane one year after the surgery was 45/48 patients. In 5 of 63 patients in whom a retro-auricular approach and wall-up technique were used, granuloma was observed along the incision in the ear canal. Granuloma was not seen in any of the 23 patients undergoing a procedure with an endaural approach. CONCLUSION: The use of a material prepared from patients themselves and not of animal origin has numerous advantages in terms of biocompatibility and safety, without any adverse effect on the success rate for general middle ear procedures. The protocol is simple and does not prolong the time spent by the patient in the operating theatre. The Choukroun technique should be modified to prevent excessive failure rates in PRF processing.

Autocrine CCL2, CXCL4, CXCL9 and CXCL10 signal in retinal endothelial cells and are enhanced in diabetic retinopathy.

This study aimed at examining the presence and role of chemokines (angiogenic CCL2/MCP-1 and angiostatic CXCL4/PF-4, CXCL9/Mig, CXCL10/IP-10) in proliferative diabetic retinopathy (PDR). Regulated chemokine production in human retinal microvascular cells (HRMEC) and chemokine levels in vitreous samples from 40 PDR and 29 non-diabetic patients were analyzed. MCP-1, PF-4, Mig, IP-10 and VEGF levels in vitreous fluid from PDR patients were significantly higher than in controls. Except for IP-10, cytokine levels were significantly higher in PDR with active neovascularization and PDR without traction retinal detachment (TRD) than those in inactive PDR, PDR with TRD and control subjects. Exploratory regression analysis identified associations between higher levels of IP-10 and inactive PDR and PDR with TRD. VEGF levels correlated positively with MCP-1 and IP-10. Significant positive correlations were observed between MCP-1 and IP-10 levels. In line with these clinical findings Western blot analysis revealed increased PF-4 expression in diabetic rat retinas. HRMEC produced MCP-1, Mig and IP-10 after stimulation with IFN-γ, IL-1ß or lipopolysaccharide. IFN-γ synergistically enhanced Mig and IP-10 production in response to IL-1ß or lipopolysaccharide. MCP-1 was produced by HRMEC in response to VEGF treatment and activated HRMEC via the ERK and Akt/PKB pathway. On the other hand, phosphorylation of ERK induced by VEGF and MCP-1 was inhibited by PF-4, Mig and IP-10. In accordance with inhibition of angiogenic signal transduction pathways, PF-4 inhibited in vitro migration of HRMEC. Thus, regulatory roles for chemokines in PDR were demonstrated. In particular, IP-10 might be associated with the resolution of active PDR and the development of TRD.

Cardiovascular determinants and prognostic significance of CC Chemokine Ligand-18 (CCL18/PARC) in patients with stable coronary artery disease.

Chemokines are important mediators of angiogenesis, hematopoiesis and leucocyte trafficking. CC Chemokine Ligand-18 (CCL18)/ pulmonary and activation-regulated chemokine (PARC) is a circulating chemokine that plays a role in injury healing, physiological homing of mononuclear blood cells and inflammatory responses. CCL18/PARC is also expressed in atherosclerotic plaques. We prospectively evaluated CCL18/PARC levels and their cardiovascular and biological determinants in a large cohort of 285 patients with stable coronary heart disease who were subsequently followed for 3 years for hard cardiac events. It was found that CCL18/PARC levels were associated with decreased cardiac function, decreased exercise capacity and increased inflammatory parameters including interleukin-6 (IL-6) and hs-CRP. More importantly high CCL18/PARC levels were an independent predictor of future cardiovascular events. Therefore, CCL18/PARC is a potential diagnostic and prognostic parameter in patients with stable coronary artery disease.

Prognostic factors and assessment of staging systems for head and neck soft tissue sarcomas in adults.

OBJECTIVES: The primary objectives of this study were to analyse the outcome of patients diagnosed with head and neck soft tissue sarcomas (HNSTS) and to identify relevant prognostic factors. As well as this, we compared the prognostic value of two staging systems proposed by the American Joint Committee on Cancer (AJCC) and the Memorial Sloan-Kettering Cancer Center (MSKCC). METHODS: From 07/1988 to 01/2008, the charts of 42 adult patients were retrospectively reviewed. Potential prognostic factors were analysed according to overall survival (OS), disease-free survival (DFS) and disease-specific survival (DSS). RESULTS: At 5 years, OS was 57%, DFS 47% and DSS 72%. On univariate analysis, statistically significant prognostic factors were for OS, distant or lymph node metastasis at diagnosis (p=0.032), for DFS, margins after surgery (p=0.007), for DSS, regional or distant metastasis at diagnosis (p=0.002), initial AJCC and MSKCC stage (p=0.018 and p=0.048) and margins after surgery (p=0.042). On multivariate analysis, margins remained statistically significant for DFS (p=0.039) when there was a trend with the initial AJCC stage (p=0.054) for OS. The AJCC staging system was of more prognostic value than the MSKCC staging system. CONCLUSIONS: Achieving clear margins after surgery is vital for improved local control and the best chance of survival. Adjuvant chemotherapy and radiotherapy were not shown to provide additional benefit. To better identify prognostic factors, it seems essential to set up national and international databases allowing multicenter registration for those patients.

Comparison between new and old generation RetroX auditory implants.

OBJECTIVE: To compare post aural soft tissues tolerance of the old and new titanium RetroX (Auric GmbH, Rheine, Germany) tube, and to compare the hearing improvements between the old (DSP-pro) and the new (Concertino) hearing aid units of the RetroX. METHODOLOGY: Retrospective case review of 46 patients with high-frequency sensorineural hearing loss, fitted with DSP-pro or Concertino, and who received 51 implantations (with the old or new generation titanium tube) in a tertiary referral center at a university hospital. The RetroX consists of an electronic unit situated in the postaural sulcus connected to a titanium tube implanted under the auricle between the sulcus and the external auditory meatus. Implanting requires minor surgery (10 minutes under local anaesthesia). Three months after their implantation, patients were asked to fill out a questionnaire to evaluate acoustic feedback annoyance and to undergo 3 audiometric tests: pure-tone audiometry in silence, speech audiometry in silence, and speech audiometry in noise. RESULTS: The new tube is more reliable (12 explantations from patients who received 26 older tubes compared with 1 explantation in 25 who received new tubes) even if the size must be adjusted more often (2/26 for the old model and 5/25 for the new one). Concertino allows a higher amplification before feedback appears, which improves hearing gain. CONCLUSIONS: The new RetroX is better tolerated than the older one, and improves hearing ability.

TNF-alpha and the IFN-gamma-inducible protein 10 (IP-10/CXCL-10) delivered by parvoviral vectors act in synergy to induce antitumor effects in mouse glioblastoma.

Interferon-gamma-inducible protein 10 is a potent chemoattractant for natural killer cells and activated T lymphocytes. It also displays angiostatic properties and some antitumor activity. Tumor necrosis factor-alpha (TNF-alpha) is a powerful immunomodulating cytokine with demonstrated tumoricidal activity in various tumor models and the ability to induce strong immune responses. This prompted us to evaluate the antitumor effects of recombinant parvoviruses designed to deliver IP-10 or TNF-alpha into a glioblastoma. When Gl261 murine glioma cells were infected in vitro with an IP-10- or TNF-alpha-transducing parvoviral vector and were subcutaneously implanted in mice, tumor growth was significantly delayed. Complete tumor regression was observed when the glioma cells were coinfected with both the vectors, demonstrating synergistic antitumor activity. In an established in vivo glioma model, however, repeated simultaneous peritumoral injection of the IP-10- and TNF-alpha-delivering parvoviruses failed to improve the therapeutic effect as compared with the use of a single cytokine-delivering vector. In this tumor model, cytokine-mediated immunostimulation, rather than inhibition of vascularization, is likely responsible for the therapeutic efficacy.

Mechanistic insight into taxol-induced cell death.

We analysed the involvement of proteases during taxol-mediated cell death of human A549 non-small-cell lung carcinoma cells using a proteomics approach that specifically targets protein N termini and further detects newly formed N termini that are the result of protein processing. Our analysis revealed 27 protease-mediated cleavages, which we divided in sites C-terminal to aspartic acid (Asp) and sites C-terminal to non-Asp residues, as the result of caspase and non-caspase protease activities, respectively. Remarkably, some of the former were insensitive to potent pancaspase inhibitors, and we therefore suggest that previous inhibitor-based studies that report on the caspase-independent nature of taxol-induced cell death should be judged with care. Furthermore, many of the sites C-terminal to non-Asp residues were also uniquely observed in a model of cytotoxic granule-mediated cell death and/or found by in vitro cataloging human mu-calpain substrates using a similar proteomics technique. This thus raises the hypothesis that killing tumor cells by chemotherapy or by immune cells holds similar non-Asp-specific proteolytic components with strong indications to calpain activity.

Circulating fibrocytes contribute to the myofibroblast population in proliferative vitreoretinopathy epiretinal membranes.

BACKGROUND/AIMS: Fibrocytes, circulating cells that co-express markers of haematopoietic stem cells, leucocytes and fibroblast products, traffic to sites of tissue injury, differentiate into myofibroblasts and contribute to wound healing and fibrosis. We investigated the presence of fibrocytes and the expression of their chemotactic pathways CCL21/CCR7 and CXCL12/CXCR4 in proliferative vitreoretinopathy (PVR) epiretinal membranes. METHODS: Sixteen membranes were studied by immunohistochemical techniques. RESULTS: Cells expressing alpha-smooth-muscle actin (alpha-SMA), a marker of differentiation of fibrocytes into myofibroblasts, were present in all membranes. Cells expressing the haematopoietic stem-cell antigen CD34, the leucocyte common antigen CD45, CCR7, CXCR4, CCL21 and CXCL12 were noted in 50%, 75%, 68.8%, 100%, 80% and 93.8% of the membranes, respectively. Double immunohistochemistry indicated that all cells expressing CD34, CD45, CCR7, CXCR4, CCL21 and CXCL12 co-expressed alpha-SMA. The number of cells expressing CD34 correlated significantly with the numbers of cells expressing CXCL12 (r(s) = 0.567; p = 0.022) and CCL21 (r(s) = 0.534; p = 0.04). CONCLUSIONS: Circulating fibrocytes may function as precursors of myofibroblasts in PVR membranes.

[The role of plasma chemokines in cancer]. / Rol van plasma-chemokinen bij kanker.

Chemokines have diverse roles in tumor biology. Monocyte chemotactic protein-(MCP-1)/CCL2 was the first chemokine described to elicit influx of monocyte/macrophages into tumors. Application of chemokines as anti-tumoral therapy to attract immunocompetent cells and to mediate the mounting of an efficient anti-tumoral response has been tested as a method to combat cancer for some years now. However, these chemokine-related therapy has not yet been approved for clinical application, although it has been tested succesfully in animal models for years now. A different kind of approach for chemokine anti-cancer therapy involves angiostatic chemokines. These chemokines inhibit pro-angiogenic tumoral factors, thereby limiting tumor growth and metastasis. Recently, we described a most potent new angiostatic chemokine, namely a variant of platelet factor 4, designated PF-4var/CXCL4L1. With regard to hematological tumors we described a new plasma chemokine, PARC/CCL18, that can be used to distinguish between pediatric patients with acute lymfoid leukemia or acute myeloid leukemia. Whether this elevated plasma concentration of PARC/CCL18 is the cause of the pathology or the consequence of a disturbed cytokine balance is not clear at the moment.

Expression of chemokines and gelatinase B in sympathetic ophthalmia.

PURPOSE: To examine the expression of gelatinase B (matrix metalloproteinase-9) and the chemokines monocyte chemotactic protein-1 (CCL2/MCP-1) and stromal cell-derived factor-1 (CXCL12/SDF-1) in sympathetic ophthalmia (SO). METHODS: Five enucleated exciting eyes with a clinical diagnosis and typical histopathological findings of SO were studied by immunohistochemical techniques using a panel of monoclonal antibodies directed against gelatinase B, MCP-1, and SDF-1. In addition, a panel of monoclonal and polyclonal antibodies was used to characterize the composition of the inflammatory infiltrate. RESULTS: In all cases, the extensive uveal inflammatory infiltrate was organized as a diffuse infiltrate and as large granulomas consisting of epithelioid cells and multinucleated giant cells. CD20(+) B lymphocytes predominated in the diffuse infiltrate and CD3(+) T lymphocytes were few. The monocyte/macrophage marker CD68 was expressed in scattered inflammatory mononuclear cells and within granulomas and Dalen-Fuchs nodules. Most of the inflammatory cells were HLA-DR(+). Immunoreactivity for gelatinase B, MCP-1, and SDF-1 was observed in cells within granulomas and in scattered epithelioid cells. Immunoreactivity for MCP-1 was noted in retinal pigment epithelial cells. Endothelial cells of choriocapillaries showed weak immunoreactivity for SDF-1. CONCLUSIONS: Gelatinase B, MCP-1, and SDF-1 might have a pathogenic role in the recruitment of leucocytes into the eye in SO.

Endonasal endoscopic resection of an ethmoidal solitary fibrous tumor.

Solitary fibrous tumor (SFT) is an uncommon spindle cell tumor that typically arises at the level of the pleura in adults. However, SFT has also been reported in various extrapleural sites including orbit, meninges, liver, lung, salivary glands, retroperitoneum, mediastinum. In the head and neck region, SFT has been documented in the external auditory canal, larynx, thyroid, sublingual gland, tongue, parapharyngeal space and the infratemporal fossa. The nose and the paranasal sinuses are a rare site for SFT with only 14 publications in the world literature. We present an additional case of a SFT arising at the level of the right ethmoid sinus successfully removed in one piece endoscopically and review the corresponding literature.

Chemokines in gastrointestinal disorders.

The intestine is constantly challenged by food antigens and pathogens and is therefore in need of a good working innate and adaptive immune response. Chemokines are important modulators as they assure the directed movement of immune cells within the body. In addition, chemokines play an important role in hematopoiesis, angiogenesis and tumor metastasis. This review focuses on chemokines and gastrointestinal disorders, more particularly on inflammatory bowel diseases and gastrointestinal tumors. In a first part, the current knowledge on chemokine expression in inflammatory bowel diseases is summarized. Idiopathic inflammatory bowel diseases are characterized by an uncontrolled immune response. The resulting chronic inflammation of the intestine involves massive infiltration of immune cells, causing intestinal damage by the release of cytokines and proteolytic enzymes. Chemokines are believed to be key mediators in this process of aberrant leukocyte recruitment. Chemokine expression in inflammatory bowel disease strongly correlates with the grade of disease activity. The potential therapeutic use of chemokines in gastrointestinal tumors by the use of gene therapy is also reviewed. Chemokines have therapeutic potential in anti-tumor therapy by their angiostatic effect. On the other hand, chemokines can augment the cell-mediated adaptive immune response and thereby exert anti-tumor activity. However, chemokines can passively favor escape of tumor cells by stimulating the release of tissue degrading matrix metalloproteinases and can actively promote metastasis of chemokine receptor-expressing tumor cells.

The role of tetraploids in the sexual-asexual cycle in dandelions (Taraxacum).

Apomictic plants often produce pollen that can function in crosses with related sexuals. Moreover, facultative apomicts can produce some sexual offspring. In dandelions, Taraxacum, a sexual-asexual cycle between diploid sexuals and triploid apomicts, has been described, based on experimental crosses and population genetic studies. Little is known about the actual hybridization processes in nature. We therefore studied the sexual-asexual cycle in a mixed dandelion population in the Netherlands. In this population, the frequencies of sexual diploids and triploids were 0.31 and 0.68, respectively. In addition, less than 1% tetraploids were detected. Diploids were strict sexuals, triploids were obligate apomicts, but tetraploids were most often only partly apomictic, lacking certain elements of apomixis. Tetraploid seed fertility in the field was significantly lower than that of apomictic triploids. Field-pollinated sexual diploids produced on average less than 2% polyploid offspring, implying that the effect of hybridization in the 2x-3x cycle in Taraxacum will be low. Until now, 2x-3x crosses were assumed to be the main pathway of new formation of triploid apomicts in the sexual-asexual cycle in Taraxacum. However, tetraploid pollen donors produced 28 times more triploid offspring in experimental crosses with diploid sexuals than triploid pollen donors. Rare tetraploids may therefore act as an important bridge in the formation of new triploid apomicts.

Expression of T lymphocyte chemoattractants and activation markers in vernal keratoconjunctivitis.

BACKGROUND/AIMS: T lymphocytes are present in increased numbers in the conjunctiva of patients with vernal keratoconjunctivitis (VKC) and their activation has a central role in the pathogenesis of the chronic allergic inflammatory reactions seen in VKC. The aims of this study were to examine the expression of three recently described potent T lymphocyte chemoattractants, PARC (pulmonary and activation regulated chemokine), macrophage derived chemokine (MDC), and I-309, the MDC receptor CCR4, and T lymphocyte activation markers, CD25, CD26, CD62L, CD71, and CD30, and to correlate them with the counts of CD3(+) T lymphocytes in the conjunctiva of patients with VKC. METHOD: Conjunctival biopsy specimens from 11 patients with active VKC, and eight control subjects were studied by immunohistochemical techniques using a panel of monoclonal and polyclonal antibodies directed against PARC, MDC, I-309, CCR4, CD25, CD26, CD62L, CD71, and CD30. The numbers of positively stained cells were counted. The phenotype of inflammatory cells expressing chemokines was examined by double immunohistochemistry. RESULTS: In the normal conjunctiva, vascular endothelial cells in the upper substantia propria showed weak immunoreactivity for CD26. There was no immunoreactivity for the other antibodies. VKC specimens showed inflammatory cells expressing PARC, MDC, and I-309. The numbers of PARC(+) inflammatory cells were higher than the numbers of MDC(+) and I-309(+) inflammatory cells and the mean values of the three groups differed significantly (17.0 (SD 10.1); 9.5 (9.9), and 4.3 (7.9), respectively, p = 0.0117, ANOVA). The numbers of PARC(+) inflammatory cells had the strongest correlation with the numbers of CD3(+) T lymphocytes. Few CCR4(+) inflammatory cells were observed in only three specimens. Double immunohistochemistry revealed that all inflammatory cells expressing chemokines were CD68(+) monocytes/macrophages. The numbers of CD25(+) T lymphocytes were higher than the numbers of CD26(+), CD62L(+), CD71(+), and CD30(+) T lymphocytes and the mean values of the five groups differed significantly (46.2 (27.9), 30.7 (16.0), 20.1 (8.6), 7.8 (7.7), and 6.5 (4.0), respectively, p <0.001, ANOVA). The numbers of CD25(+) T lymphocytes had the strongest correlation with the numbers of CD3(+) T lymphocytes. CONCLUSION: These results suggest a potential role for PARC, MDC, and I-309 in attracting T lymphocytes into conjunctiva in VKC. T lymphocytes in VKC are activated and express several activation markers which might contribute to the pathogenesis of VKC.

Up-regulation of FPR2, a chemotactic receptor for amyloid beta 1-42 (A beta 42), in murine microglial cells by TNF alpha.

Human FPRL1 and its mouse homologue FPR2 are functional receptors for several exogenous and host-derived chemotactic peptides, including amyloid beta(42) (A beta(42)), a critical pathogenic factor in Alzheimer's disease. We investigated the effect of TNF alpha on the expression and function of FPR2 in mouse microglial cells, a crucial inflammatory cell type in the CNS. Primary murine microglia and a cell line N9 in resting state expressed low levels of FPR2 gene and lacked the response to chemotactic agonists for this receptor. Incubation with TNF alpha, however, increased microglial expression of FPR2 gene, in association with potent chemotactic responses to FPR2-specific agonists including A beta(42). The effect of TNF alpha was dependent on the p55 TNF alpha receptor and activation of MAP kinase p38. TNF alpha concomitantly down-regulated microglial response to the chemokine SDF-1 alpha. Thus, by selectively up-regulating FPR2 in microglia, TNF alpha has the capacity to amplify host response in inflammatory diseases in the CNS.

Chemokines and proteinases in autoimmune diseases and cancer.

Chemotactic cytokines or chemokines form a family of proinflammatory proteins that are functionally linked to various classes of proteases, including matrix metalloproteinases (MMPs). Both families of molecules are key players in the migration of inflammatory cells in autoimmune diseases and in invasive cancers. For example, the chemokine interleukin-8 acts as a fast secretagogue of gelatinase B in granulocytes and is increased in the synovial fluid of arthritis patients and may locally recruit and activate neutrophils. The latter are the most abundant inflammatory cell type in the joints of patients with rheumatoid arthritis. In the case of the inflamed joint, the contribution of matrix remodeling enzymes in the breakdown of cartilage and bone is trivial. Gelatinase B (MMP-9) was documented in autoimmune diseases and cancer by immunohistochemistry with the use of monoclonal antibodies. Studies in rheumatoid arthritis and multiple sclerosis led us to postulate the "Remnant Epitopes Generate Autoimmunity" or REGA model for autoimmunity. This model is based on the pathophysiological role of three major classes of molecules involved in aspecific primary immune defense mechanisms: the cytokines, the chemokines and the proteases. The REGA model has proven to be useful for the development of disease treatment strategies. Particular cytokines are disease-limiting and may thus be used for the treatment of autoimmune disorders. Cytokines and chemokines that induce enzymes promote disease and may be antagonized. Along this line of research, we have recently identified natural and biosynthetic chemokine antagonists. Some of these have shown potent antiviral activity against human immunodeficiency virus. It is expected that these might also become useful in the treatment of autoimmune diseases and invasive cancers. A similar effect may be expected by the antagonization of damaging proteases or with the use of recombinant or synthetic enzyme inhibitors.

Neutrophil gelatinase B and chemokines in leukocytosis and stem cell mobilization.

Leukocytosis is a physiopathological mechanism primarily to combat infections, whereas stem cell mobilization is induced for therapeutical purposes. Both processes are dependent on the balance between leukocyte and stem cell retention and mobilization. The retention is mediated by the specific architecture of the bone marrow, adhesion molecules and the production of chemokines in the bone marrow, which attract escaped immature cells to the marrow. Mobilization is the effect of the action of "peripheral" chemokines, such as interleukin-8 (IL-8 or CXCL8) and the remodeling of the matrix and basement membranes by matrix enzymes, such as gelatinase B (MMP-9). Recent studies lead to the conclusion that neutrophils, IL-8/CXCL8 and gelatinase B/MMP-9 play control roles in leukocytosis and stem cell mobilization. Neutrophils are the predominant circulating leukocyte type and IL-8/CXCL8 is the major neutrophil chemoattractant in humans. Gelatinase B and no gelatinase A is rapidly released from prestored granules after activation of neutrophils by IL-8/CXCL8. Moreover, neutrophils do not produce TIMP-1 and can chemically activate latent progelatinase B. Activated gelatinase B catalyses the aminoterminal truncation of IL-8/CXCL8 into a tenfold more potent chemokine. This implies that, when IL-8/CXCL8 appears in the circulation, the bone marrow is instructed to release neutrophils and concomitantly stem cells. These studies suggest that IL-8/CXCL8 and gelatinase B/MMP-9 are targets for the modulation of stem cell mobilization.

Amino-terminal truncation of CXCR3 agonists impairs receptor signaling and lymphocyte chemotaxis, while preserving antiangiogenic properties.

The interferon (IFN)-inducible chemokines, specifically, IFN-gamma-inducible protein-10 (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha-chemoattractant (I-TAC), share a unique CXC chemokine receptor (CXCR3). Recently, the highly specific membrane-bound protease and lymphocyte surface marker CD26/dipeptidyl peptidase IV (DPP IV) was found to be responsible for posttranslational processing of chemokines. Removal of NH(2)-terminal dipeptides by CD26/DPP IV alters chemokine receptor binding and signaling, and hence inflammatory and anti-human immunodeficiency virus (HIV) activities. CD26/DPP IV and CXCR3 are both markers for Th1 lymphocytes and, moreover, CD26/DPP IV is present in a soluble, active form in human plasma. This study reports that at physiologic enzyme concentrations CD26/DPP IV cleaved 50% of I-TAC within 2 minutes, whereas for IP-10 and Mig the kinetics were 3- and 10-fold slower, respectively. Processing of IP-10 and I-TAC by CD26/DPP IV resulted in reduced CXCR3-binding properties, loss of calcium-signaling capacity through CXCR3, and more than 10-fold reduced chemotactic potency. Moreover, IP-10 and I-TAC cleaved by CD26/DPP IV acted as chemotaxis antagonists and CD26/DPP IV-truncated IP-10 and Mig retained their ability to inhibit the angiogenic activity of interleukin-8 in the rabbit cornea micropocket model. These data demonstrate a negative feedback regulation by CD26/DPP IV in CXCR3-mediated chemotaxis without affecting the angiostatic potential of the CXCR3 ligands IP-10 and Mig.