Prognostic value of coronary flow and heart rate reserve in emergency department chest pain

Aims

To estimate the prognostic value of stress echo (SE) with the assessment of coronary flow velocity reserve (CFVR) and heart rate reserve (HRR) in patients admitted for chest pain with non-diagnostic EKG, negative troponin, and without inducible regional wall motion abnormalities (RWMA).

Methods

658 patients (age 67±12 years) admitted to our Emergency Department with chest pain, non-diagnostic EKG, and negative serial troponin underwent dipyridamole (0.84 mg/kg in 6') SE with simultaneous assessment of RWMA, CFVR in the left anterior descending artery, and HRR as peak/rest heart rate. The outcome measure was all-cause mortality.

Results

Of the 658 patients initially enrolled, 20 (3%) showed RWMA during SE and were referred to ischemia-driven revascularization. In the remaining 638, CFVR was abnormal (<2.0) in 148 patients (23%). HRR was abnormal (<1.22 in patients in sinus rhythm, or <1.17 in patients with permanent atrial fibrillation) in 196 patients (31%). The main clinical and echocardiographic characteristics according to CFVR and HRR response are shown in Table 1. During a follow-up of 7.3±4.3 years, 151 (24%) patients died. Survival at 8 years was 93% in patients with normal CFVR and HRR, 76% in patients with abnormal CFVR only, 73% in patients with abnormal HRR only, and 38% in those with abnormal CFVR and HRR (p<0.0001) (Figure 1). At multivariable analysis, abnormal CFVR (HR 1.49, 95% CI 1.05–2.10, p=0.02) and abnormal HRR (HR 2.01, 95% CI 1.43–2.84, p<0.0001) were independent predictors of survival.

Conclusions

In admitted patients with non-ischemic EKG, negative serial troponin, and whitout RWMA during dipyridamole SE, a reduced CFVR and blunted HRR independently identify a subset with worse survival in the long-term.

Funding Acknowledgement

Type of funding sources: None.

C88 EFFECT OF SARS–COV2 INFECTION ON ACUTE CORONARY SYNDROME: A RETROSPECTIVE OBSERVATIONAL STUDY

Introduction

In Northern Italy, from October 2020 to April 2021, the second wave of COVID–19 pandemic recorded the highest incidence of infections ever. In this semester, the Lombardy region alone counted 43,318 positive cases and 16,710 deaths. It is well known how COVID–19 leads to a negative prognosis in acute coronary syndrome (ACS). This study aims to analyze the dramatic consequences of SARS–CoV2 infection on patients with concomitant ACS during the worst pandemic period ever recorded in Northern Italy.

Materials and Methods

The study enrolled 255 consecutive patients who have been hospitalized for ACS (STEMI or NSTEMI) from October 2020 to April 2021, both from the hub and spoke hospitals. Two subgroups are compared: the first is composed of patients who have tested positive for at least one molecular SARS–CoV2 swab (at admission or during hospitalization), the other group is composed of patients who have been tested negative to SARS–CoV2 swab. Major clinical data, risk factors (RF), comorbidities, laboratory findings, reperfusion times, drug therapy, complications and in–hospital mortality were systematically collected.

Results

Patients main characteristics are shown in Table 1. No differences have been observed in clinical history, RF and comorbidities in the subgroups. At admission, the incidence of acute pulmonary edema (APE) and respiratory symptoms was significantly higher in the SARS–CoV2 group, respectively 14% (p = 0.005) and 18% (p = 0.017). No differences in the “onset to door” and “door to needle” delays have been recorded. The incidence of the composite in–hospital complications is markedly increased in SARS–CoV2 group. Compared to negative patients, a higher mortality rates (18% Vs. 4%; p = 0.017), higher incidences of acute renal failure (ARF) (18% Vs. 5%; p = 0.037), cardiogenic shock (14% Vs. 3%; p = 0.033) and a wider prescription of inotropes (23% Vs. 10%; p = 0.009) in the SARS–CoV2 cohort.

Conclusion

The study confirms the negative prognostic impact of COVID–19 infection on ACS, recording a significantly higher rate of all major complications, both related to ischemia with multiorgan failure and interstitial pneumonia. Higher incidence of APE, cardiogenic shock and ARF has been observed in SARS–CoV2 positive subgroup, which is corroborated by a quadrupled risk of in–hospital mortality in the COVID–19 cohort.

Effect of Phenobarbital on Cyclophosphamide Cytotoxic Activity and Pharmacokinetics in Mice

The interaction between cyclophosphamide (CPA) and phenobarbital (PB) was investigated in B6D2F, mice, checking both the antileukemic and immunosuppressive activity together with the serum levels of CPA and its metabolites. A reduced cytotoxic activity of CPA has been observed when PB is given for 2 days before CPA and an interval of at least 6 hours elapses between the last treatment of PB and the administration of CPA. On the contrary, when PB is given simultaneously with CPA for 2 or 4 consecutive days, an increased antileukemic activity of CPA occurs. In the experimental condition where PB decreases the activity of CPA, serum levels of CPA, assayed by means of a new specific gas-chromatographic method, and of its NBP-alkylating metabolites, indicate that this effect may be explained on a pure pharmacokinetic basis. However, for the situation where an increased effect of CPA was observed under the influence of PB, pharmacokinetic data did not provide a clear explanation.

Deposition of tetraferrocenylporphyrins on ITO surfaces for photo-catalytic O2 activation

Tetraferrocenylporphyrins have been successfully deposited on ITO electrodes for O₂ photo-catalytic activation.

Liver transplantation in neurological Wilson's Disease: is there indication? A case report

Wilson's disease (WD) is an autosomal recessive disorder characterized by copper overload. In this disease, inadequate hepatic excretion leads to copper accumulation in the liver, brain, kidney, and cornea. Severe neurological symptoms can develop in patients with WD, often in the absence of relevant liver damage: it is unclear whether liver transplantation (LT) could reverse neurological symptoms, and at present LT is not recommended in this setting. We report a case of regression of neurological symptoms in a patient affected by WD with prevalent neurological involvement. A 19-year-old man with disabling neuropsychiatric symptoms from WD that included frontal ataxia, akinesia, dystonia, tremors, and behavioral disorders in the presence of preserved liver function (Model for End-Stage Liver Disease score=7; Child-Turcotte-Pugh score=A5) underwent LT in November 2009. At the time of LT, encephalic magnetic resonance imaging (MRI) indicated diffuse neurodegenerative alterations involving subtentorial and supratentorial structures; bilateral Kayser-Fleischer ring was present. Four years after LT, laboratory tests show normalized copper metabolism and excellent liver function test results. Encephalic MRI shows a substantial improvement of already-known signal alterations at nuclei thalamus and putamen, mesencephalon, and pons. Kayser-Fleischer ring disappeared from the right eye, but a little remnant is still visible in the left eye. At neurological examination, all of the previous symptoms and signs are no longer present and behavioral disorders are no longer present; psychosocial functions are completely restored. The present case provides some evidence that LT may be a valid therapeutic option for WD patients with marked neurological impairment, particularly in those no longer responsive to chelation therapy.

Elderly versus young liver transplant recipients: patient and graft survival

The indications for organ transplantation continue to broaden with advances in perioperative care and immunosuppression. The elderly have especially benefited from this progress; advanced age is no longer considered a contraindication to transplantation at most centers. Although numerous studies support the use of renal allografts in older patients, only a few centers have addressed this issue as it pertains to liver transplantation. Published studies have revealed that operative course, length of hospitalization, and incidence of perioperative complications among patients older than 60 years of age are comparable with their younger adult counterparts. In our study we analyzed the clinical experiences of two centers with primary cadaveric orthotopic liver transplantations comparing patients older than 63 with patients younger than 40 years of age, suggesting no difference in unadjusted survival with age stratification. Now age cannot be considered to be a contraindication to liver transplantation.

Anti-phospholipid antibody mediated fetal loss: still an open question from a pathogenic point of view

Antiphospholipid antibodies (aPL) are associated with recurrent miscarriages and pregnancy complications, however their pathogenic mechanisms are still matter of research. Thrombotic events at the placental level cannot explain all of the clinical manifestations. It has been suggested that aPL may be responsible for a local acute inflammatory response mediated by complement activation and neutrophil infiltration eventually leading to fetal loss. However histological and immunohistological studies on human placental samples do support such a mechanism only in part and with no any clear relationship with the pregnancy outcome. A direct effect of aPL on both maternal and fetal placental tissues has been reported through the reactivity of the antibodies with beta2 glycoprotein I (beta2GPI) expressed on the cell membranes. These events do not require an inflammatory response and can be in part related to the inhibition of growth factors favouring a physiological placentation. Understanding the different pathogenic mechanisms of aPL-associated miscarriages may help in improving our therapeutic approach particularly in recurrent cases not responsive to the usual treatment.

Technical solutions for venous outflow reconstruction in damaged liver grafts during procurement: case reports

The incidence and clinical consequences of hepatic injuries (parenchymal, vascular, and biliary) due to surgical handling during multiorgan procurement are still underestimated. Surgical damage to liver grafts may lead to an increased mortality and graft dysfunction rate; therefore, multiorgan procurements require a high level of expertise and training. We report our experience in two cases of accidental venous outflow damage during liver procurement focusing on our repair strategies. In one case, a short suprahepatic inferior vena cava (IVC) was extended by a venous cuff obtained from a long infrahepatic IVC from the same liver graft. In the second case, we observed a complete transection of the middle hepatic vein during in situ splitting procedure. The damage was reconstructed by cadaveric iliac vein interposition. In both cases, liver transplantation was successfully performed without venous complication. An adequate surgical technique in liver procurement and venous reconstruction during living donor and domino liver transplantation are formidable tools to achieve successful liver transplantation with a damaged graft.

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.

Peritoneal leiomyosarcoma in a kidney transplant patient: a case report

Sarcomas are rare neoplasms, accounting for a 1.7% incidence among all transplanted patients presenting with de novo malignancies. Our present report focused on a 46-year-old woman who received immunosuppressive therapy based on cyclosporine and steroids for renal transplantation. Eight years after transplantations, she suffered lower abdominal pain and a mass involving peritoneal soft tissues was located near the right iliac vessels. Upon radical tumor excision, the histological examination revealed a high-grade leiomyosarcoma. Immunosuppression was reduced and cyclosporine switched to rapamycin. After 30 days, a computed tomography scan revealed two small pulmonary metastases, so the patient received adriamycin. Six months after the diagnosis, there was no intra-abdominal relapse and the pulmonary metastasis remain stable. The function of the transplanted kidney was normal and the patient was listed for laparoscopic pulmonary resection. Sarcomas in solid organ transplant patients appear to have aggressive features with 62% being high grade and 40% metastatic at the time of primary diagnosis with a recurrence rate of 30% and a 5-year survival rate of 25%. Patients diagnosed with sarcoma should be treated with multimodality therapy. After aggressive surgery whenever possible, a combination of a traditional cytotoxic drug and a "signal" blocking agent like rapamycin may increase selectivity toward tumor cells.

The chemoattractant decoy receptor D6 as a negative regulator of inflammatory responses

Other than signalling receptors sustaining leucocyte recruitment during inflammatory reactions, the chemokine system includes 'silent' receptors with distinct specificity and tissue distribution. The best-characterized molecule of this subgroup is the CC chemokine receptor D6, which binds most inflammatory CC chemokines and targets them to degradation via constitutive ligand-independent internalization. Structure-function analysis and recent results with gene-targeted animals indicate that D6 has unique functional and structural features, which make it ideally adapted to act as a chemokine decoy and scavenger receptor, strategically located on lymphatic endothelium and placenta to dampen inflammation in tissues and draining lymph nodes.

Hepatic portal venous gas in a patient with enterovascular fistula

Hepatic portal venous gas is an uncommon clinical condition that is often characterized by acute onset of abdominal pain and is associated with a high rate of mortality despite clinical and/or surgical treatment. Radiologic diagnosis is important and usually includes abdominal radiography, ultrasound, and computed tomography. We describe the clinical, computed tomographic, and angiographic data of a patient with sigmoid diverticulitis who developed a massive embolism of the intra- and extrahepatic portal systems due to an enterovascular fistula and was treated with fistula embolization and subsequent sigmoidectomy.

Transduction of human MCP-3 by a parvoviral vector induces leukocyte infiltration and reduces growth of human cervical carcinoma cell xenografts

BACKGROUND

The oncosuppressive properties of some autonomous parvoviruses such as H-1 virus, together with their low pathogenicity, make them attractive vectors for tumor-directed gene therapy. Indeed, it was recently shown that these viruses became endowed with an enhanced oncosuppressive activity after they had been engineered to deliver a recognized therapeutic transgene. This prompted us to use a parvoviral vector to analyse the antineoplastic capacity of MCP-3 (monocyte chemotactic protein-3), a CC chemokine which has a broad spectrum of target cells, and can thus be considered to be a promising candidate for cancer treatment.

METHODS

We explored the use of a parvovirus H-1-based vector encoding human MCP-3 for its antitumor potential on human cervical carcinoma cells. HeLa cells were infected in vitro with the recombinant virus hH1/MCP-3 at a low multiplicity [1 replication unit (RU)/cell] and we investigated the effect of parvovirus-mediated MCP-3 transduction on tumor formation and growth upon implantation of HeLa cells in nude mice.

RESULTS

Infection of HeLa cells with hH1/MCP-3 led to secretion of high levels of MCP-3 and to significant retardation of tumor growth in recipient mice, as compared with HeLa cells that were either buffer-treated or infected with a MCP-3-free vector. Tumors from hH1/MCP-3-infected HeLa cells were heavily infiltrated with activated macrophages and showed increased numbers of dendritic cells. In addition, activated natural killer (NK) cells were also recruited into MCP-3-transduced tumors.

CONCLUSION

These observations indicate that parvovirus H-1-transduced MCP-3 is able to exert a significant antitumor activity which is mediated, at least in part, through macrophages and NK cells, under conditions in which activated T cells are lacking.

Decoy receptors: a strategy to regulate inflammatory cytokines and chemokines

The canonical concept of a receptor includes specific ligand recognition, usually with high affinity and specificity, and signaling. Decoy receptors recognize certain inflammatory cytokines with high affinity and specificity, but are structurally incapable of signaling or presenting the agonist to signaling receptor complexes. They act as a molecular trap for the agonist and for signaling receptor components. The interleukin-1 type II receptor (IL-1RII) was the first pure decoy to be identified. Decoy receptors have subsequently been identified for members of the tumor necrosis factor receptor and IL-1R families. Moreover, silent nonsignaling receptors could act as decoys for chemokines. Therefore, the use of decoy receptors is a general strategy to regulate the action of primary pro-inflammatory cytokines and chemokines.

Fractalkine (CX3CL1) as an amplification circuit of polarized Th1 responses

Fractalkine (FKN, CX3CL1) is a membrane-bound CX3C chemokine induced by primary proinflammatory signals in vascular endothelial cells (ECs). Here we examined the role of FKN in polarized Th1 or Th2 responses. Proinflammatory signals, including LPS, IL-1, TNF, and CD40 ligand, induced FKN, as did IFN-gamma, which had synergistic activity with TNF. IL-4 and IL-13 did not stimulate the expression of FKN and markedly reduced induction by TNF and IFN-gamma. TNF alone or combined with IFN-gamma also induced release of soluble FKN, which was inhibited by IL-4 and IL-13. In light of this differential regulation of FKN by the master cytokines that control polarized responses, we analyzed the interaction of FKN with natural killer (NK) cells and polarized T-cell populations. NK cells expressed high levels of the FKN receptor CX3CR1 and responded to FKN. CX3CR1 was preferentially expressed in Th1 compared with Th2 cells. Th1 but not Th2 cells responded to FKN. By immunohistochemistry, FKN was expressed on ECs in psoriasis, a Th1-dominated skin disorder, but not in Th2-driven atopic dermatitis. Similarly, ECs in Mycobacterium tuberculosis granulomatous lymphadenitis, but not those in reactive lymph node hyperplasia or in Castelman's disease, showed immunoreactive FKN. These results indicate that regulated expression of FKN in ECs participates in an amplification circuit of polarized type I responses.

Differential effect of benzydamine on pro- versus anti-inflammatory cytokine production: lack of inhibition of interleukin-10 and interleukin-1 receptor antagonist

The production and action of primary proinflammatory cytokines are strictly controlled by a series of circuits to avoid damage that they can cause if produced in excess. Interleukin-10 and interleukin-1 receptor antagonist contribute to the control of the magnitude of the inflammatory responses in vivo. Benzydamine, a non-steroidal anti-inflammatory drug that has been shown to have suppressive activity for the proinflammatory cytokines, tumor necrosis factor-alpha and interleukin-1beta, was investigated for its effects on interleukin-10 and interleukin-1ra production. The drug did not modify the production of interleukin-10 and interleukin-1ra by peripheral blood mononuclear cells stimulated with lipopolysaccharide, under conditions where tumor necrosis factor-alpha and interleukin-1beta were decreased. The antiinflammatory capacity of benzydamine might thus result from its ability to reduce the production of proinflammatory cytokines, without affecting antiinflammatory factors.

Uncoupling of inflammatory chemokine receptors by IL-10: generation of functional decoys

As originally demonstrated for the interleukin 1 (IL-1) type II receptor, some primary proinflammatory cytokines from the IL-1 and tumor necrosis factor families are regulated by decoy receptors that are structurally incapable of signaling. Here we report that concomitant exposure to proinflammatory signals and IL-10 generates functional decoy receptors in the chemokine system. Inflammatory signals, which cause dendritic cell (DC) maturation and migration to lymphoid organs, induce a chemokine receptor switch, with down-regulation of inflammatory receptors (such as CCR1, CCR2, CCR5) and induction of CCR7. Concomitant exposure to lipopolysaccharide (LPS) and IL-10 blocks the chemokine receptor switch associated with DC maturation. LPS + IL-10-treated DCs showed low expression of CCR7 and high expression of CCR1, CCR2 and CCR5. These receptors were unable to elicit migration. We provide evidence that uncoupled receptors, expressed on LPS + IL-10-treated cells, sequester and scavenge inflammatory chemokines. Similar results were obtained for monocytes exposed to activating signals and IL-10. Thus, in an inflammatory environment, IL-10 generates functional decoy receptors on DC and monocytes, which act as molecular sinks and scavengers for inflammatory chemokines.

The chemokine receptor switch paradigm and dendritic cell migration: its significance in tumor tissues

Localization in tissues and migration to lymphoid organs are essential steps in the immunobiology of dendritic cells (DC). Chemokines play an important role in guiding the traffic of DC. Receptor expression and responsiveness to constitutively made chemokines account for the presence of DC in normal tissues. Inflammatory chemokines and non-chemokine attractants promote recruitment and localization of DC at sites of inflammation and infection. During maturation, DC undergo a profound and orderly rearrangement of their chemokine receptor repertoire. The chemokine receptor switch paradigm provides a conceptual framework for the complex migration of DC in vivo, including their recruitment and positioning in tumor tissues.

Inhibition of monocyte chemotactic protein-1 synthesis by statins

The beneficial effects of statins on the reduction of cardiovascular events has been partly attributed to their anti-inflammatory properties. In the complex of the different pathogenetic events leading to atherosclerosis, recent data suggest a central role of monocyte chemotactic protein-1 (MCP-1), because mice knock-out for MCP-1 or its receptor CC-chemokine receptor 2 were considerably resistant to plaque formation. In this study we investigated the effect of different statins on in vitro and in vivo production of MCP-1. Lovastatin and simvastatin caused a dose-dependent inhibition of MCP-1 production in peripheral blood mononuclear cells exposed to lipopolysaccharide or inactivated Streptococcus hemoliticus and in human endothelial cells exposed to interleukin-1beta. The addition of mevalonate overrode the inhibitory effect of statins indicating that mevalonate-derived products are important for chemokine production. The in vivo anti-inflammatory effect of statins was investigated using the mouse air-pouch model of local inflammation. Lovastatin and pravastatin were orally administered to mice according to a treatment schedule that significantly inhibited the hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity without affecting total blood cholesterol. At the dose of 10 mg/kg, lovastatin and pravastatin reduced by approximately 50% the lipopolysaccharide-induced leukocytes recruitment and the exudate MCP-1 production. In conclusion, statins, by inhibiting mevalonate-derived products, reduced both in vitro and in vivo the production of chemokines involved in leukocyte migration, and this effect is unrelated to their cholesterol-lowering action.

Chemokines and dendritic cell traffic

Localization in tissues and migration to lymphoid organs are essential steps in the immunobiology of dendritic cells (DC). Chemokines play an important role in guiding the traffic of DC. Receptor expression and responsiveness to constitutively made chemokines account for the presence of DC in normal tissues. Inflammatory chemokines and nonchemokine attractants promote recruitment and localization of DC at sites of inflammation and infection. Upon exposure to maturation signals, DC undergo a chemokine receptor switch, with down-regulation of inflammatory chemokine receptors followed by induction of CCR7. These temporally coordinated events allow DC to leave tissues and to localize in lymphoid organs by responding to CCR7 agonists. DC are also present in tumors that produce chemokines, but their significance remains to be defined. In addition to responding to chemokines, DC are a major source of certain chemokines such as macrophage-derived chemokine. The interaction of DC with chemokines is essential to the function of these cells in normal and pathological conditions and may provide tools for novel therapeutic strategies.

Chemokine receptors: interaction with HIV-1 and viral-encoded chemokines

Chemokines are a superfamily of proteins that play a central role in immune and inflammatory reactions and in viral infections. About 50 different chemokines divided in four subfamilies are known, CXC, CC, C, and CX3C. Chemokine receptors can function as entry/fusion co-receptors for human immunodeficiency virus (HIV)-1 infection, and regulation of receptor expression by cytokines may be relevant for viral infection. Posttranslational processing of chemokines can profoundly affect their interaction with receptors. The serine protease CD26/dipeptidyl-peptidase IV (CD26/DPP IV) removes NH2-terminal dipeptides from several chemokines and profoundly affect their biological activity. Kaposi's sarcoma (KS)-associated herpes virus 8 encodes for three chemokine-like proteins that show homology with MIP cluster of CC chemokines. These viral chemokines possess a partial agonist activity for certain chemokine receptors and may function as receptor antagonists. This biological activity could represent a strategy developed by the virus to subvert immunity impairing the generation of an effective anti-viral immune response.

The type II decoy receptor of IL-1 inhibits murine collagen-induced arthritis

IL-1 is a key cytokine involved in the inflammatory response. The type II receptor of IL-1 (IL-1RII) acts as a decoy receptor, binding and inhibiting the effect of IL-1. This study was undertaken to establish whether IL-1RII can ameliorate collagen-induced arthritis, a model of inflammatory arthritis in mice. We used human keratinocytes transfected with the human (h)IL-1 RII gene as a source of hIL-1 RII protein. We showed that these cells expressed both the membrane and soluble form of receptor. In vitro, IL-1-stimulated murine macrophage cells showed a decreased expression of TNF-alpha in the presence of hIL-1 RII. We engrafted the hIL-1RII-transfected cells in the back of mice developing collagen-induced arthritis. We found that clinical and histological parameters of arthritis were significantly decreased in mice treated with cells producing hIL-1RII. In addition, hIL-1RII administration was able to reduce the expression of mRNA for IL-6 and myeloperoxidase in the joints of treated animals. These data show that hIL-1 RII anti-inflammatory properties in the model of collagen-induced arthritis in mice and could have a regulatory role in rheumatoid arthritis.

Autocrine production of IL-10 mediates defective IL-12 production and NF-kappa B activation in tumor-associated macrophages

IL-12 is a central cytokine in the activation of inflammation and immunity and in the generation of Th1-type responses. Tumor-associated macrophages (TAM) from mouse and human tumors showed defective production of IL-12. Defective IL-12 production was associated with lack of p50/p65 NF-kappa B activation. TAM produced increased amounts of the immunosuppressive cytokine IL-10. Abs against IL-10 restored the defective capacity of TAM to produce IL-12. Our data suggest that during tumor growth an IL-10-dependent pathway of diversion of macrophage function can be activated into the tumor microenvironment and results in the promotion of the IL-10+ IL-12- phenotype of TAM. Blocking IL-10, as well as other immunosuppressive cytokines present in the tumor microenvironment, such as TGF-beta, may complement therapeutic strategies aimed at activating type I antitumor immune responses.

A small synthetic molecule capable of preferentially inhibiting the production of the CC chemokine monocyte chemotactic protein-1

Blocking chemokine production or action is a major target for pharmacological intervention in different human diseases. Bindarit (2-methyl-2-[[1-(phenylmethyl)-1H-indazol-3yl]methoxy]propan oic acid) dose-dependently inhibited MCP-1 and TNF-alpha production induced in vitro in monocytes by LPS and Candida albicans. It did not affect the production of the cytokines IL-1, IL-6, or the chemokines IL-8, MIP-1alpha and RANTES. In the air pouch model in mice, oral treatment reduced monocyte recruitment and local MCP-1 production, induced by carrageenan or IL-1 injection. In NZB/W mice, a model of lupus nephritis, oral treatment prolonged survival and delayed the onset of proteinuria. The results presented here show that bindarit is a preferential inhibitor of the production of MCP-1 in vitro and in vivo and suggest that its beneficial effects in models of joint and kidney inflammation are related to its anti-MCP-1 action. It is therefore possible to selectively and differentially regulate chemokines by targeting their production with small synthetic molecules.

Differential responsiveness to constitutive vs. inducible chemokines of immature and mature mouse dendritic cells

Upon exposure to immune or inflammatory stimuli, dendritic cells (DC) migrate from peripheral tissues to lymphoid organs, where they present antigen. The molecular basis for the peculiar trafficking properties of DC is largely unknown. In this study, mouse DC were generated from CD34+ bone marrow precursors and cultured with granulocyte-macrophage-CSF and Flt3 ligand for 9 days. Chemokines active on immature DC include MIP1alpha, RANTES, MIP1beta, MCP-1, MCP-3, and the constitutively expressed SDF1, MDC, and ELC. TNF-alpha-induced DC maturation caused reduction of migration to inducible chemokines (MIP1alpha, RANTES, MIP1beta, MCP-1, and MCP-3) and increased migration to SDF1, MDC, and ELC. Similar results were obtained by CD40 ligation or culture in the presence of bacterial lipopolysaccharide. TNF-alpha down-regulated CC chemokine receptor (CCR)1, CCR2, and CCR5 and up-regulated CCR7 mRNA levels, in agreement with functional data. This study shows that selective responsiveness of mature and immature DC to inducible vs. constitutively produced chemokines can contribute to the regulated trafficking of DC.

The role of chemokines in the regulation of dendritic cell trafficking

The immunobiology of dendritic cells (DC) involves localization in tissues and trafficking via the lymph or blood to lymphoid organs. Appropriate assays representative of different steps of DC trafficking (e.g., reverse transmigration) provide the tools to dissect the migratory properties of these cells. Chemokines have emerged as important regulators of DC migration. DC are both the target and the source of chemokines. DC express receptors for and respond to a set of chemoattractants that overlap with, but are distinct from, those active on other leukocytes. Differential expression of the CCR6 receptor reveals heterogeneity among DC populations. Functional maturation is associated with loss of responsiveness to chemokines present at sites of inflammation and acquisition of a receptor repertoire that renders these cells responsive to signals that guide their localization in lymphoid organs. A better understanding of the molecular basis of DC trafficking may provide molecular and conceptual tools to direct and modulate DC traffic as a strategy to up-regulate and orient specific immunity.

The viral chemokine macrophage inflammatory protein-II is a selective Th2 chemoattractant

Kaposi's sarcoma (KS) lesions are characterized by a prominent leukocyte infiltrate composed of mononuclear phagocytes and T cells. KS-associated CD4(+) and CD8(+) cells showed predominantly a type II cytokine profile. The CC chemokine viral macrophage inflammatory protein-II (vMIP-II) encoded by the KS-associated herpes virus 8 was a selective chemoattractant for T helper 2 (Th2 cells) and for monocytes, whereas it was inactive on other leukocytes, including Th1 cells, dendritic cells, and natural killer (NK) cells. vMIP-II was an agonist for CCR8, a chemokine receptor selectively expressed on CD4(+) and CD8(+) cells with a type II cytokine profile. Hence, vMIP-II has agonist activity for a chemokine receptor (CCR8), which is preferentially expressed on polarized Th2 cells. The capacity of vMIP-II to attract type II T cells selectively is likely to be a component of the virus strategy to subvert the host immune response.

Chemokines and chemokine receptors during activation and deactivation of monocytes and dendritic cells and in amplification of Th1 versus Th2 responses

Chemokines are a superfamily of small cytokines which are generally chemotactic for leukocytes. The general features of chemokines and their receptors are reviewed. Recent evidence indicates that receptor expression dictates the spectrum of action of chemokines, as shown recently for Th1 and Th2 cells. Chemokines represent amplification loops of polarized Th1 and Th2 responses. Receptor expression is tightly regulated during differentiation, activation, and deactivation of mononuclear phagocytes and dendritic cells. Thus, regulation of receptor expression is crucial as a set point of the chemokine system.

Reduced tumorigenicity and augmented leukocyte infiltration after monocyte chemotactic protein-3 (MCP-3) gene transfer: perivascular accumulation of dendritic cells in peritumoral tissue and neutrophil recruitment within the tumor

Monocyte chemotactic protein-3 (MCP-3) is a C-C chemokine that interacts with the CCR1, CCR2, and CCR3 receptors and has a spectrum of action encompassing T cells, NK cells, eosinophils, and dendritic cells (DC), in addition to mononuclear phagocytes. This broad spectrum of action prompted the present study aimed at assessing the antitumor activity of MCP-3 in a gene transfer approach and at providing information as to the actual in vivo leukocyte recruiting capacity of MCP-3. P815 mastocytoma cells transfected with the gene coding MCP-3 (P815/MCP-3) grew in syngeneic hosts and underwent rejection. Rejection was associated with profound alterations of leukocyte infiltration and resistance to subsequent challenge with P815 cells. Tumor-associated macrophages, already present in copious numbers, T cells, eosinophils, and neutrophils, increased in tumor tissues after gene transfer. DC, identified as DEC205+, high MHC class II+, CD11c+ cells, did not increase substantially in the tumor mass. However, in peritumoral tissues, DC accumulated in perivascular areas. P815/MCP-3-transfected tumor cells grew normally in nude mice. Increased accumulation of macrophages and polymorphonuclear neutrophils was evident also in nude mice. mAb against CD4, CD8, and IFN-gamma, but not against IL-4, inhibited rejection of MCP-3-producing cells. An anti-polymorphonuclear mAb caused only a retardation of MCP-3-elicited tumor rejection. Thus, MCP-3 gene transfer elicits tumor rejection by activating type I T cell-dependent immunity. It is tempting to speculate that altered trafficking of APCs, which express receptors and respond to MCP-3, together with recruitment of activated T cells, underlies activation of specific immunity by MCP-3-transfected cells.

Immunohistochemical localization of the murine transferrin receptor (TfR) on blood-tissue barriers using a novel anti-TfR monoclonal antibody

A novel monoclonal antibody (mAb), 8D3 (IgG2a), that specifically recognizes the murine transferrin receptor (TfR) was produced by immunizing a Lewis rat with a polyoma middle T oncogene-transformed endothelioma cell line. The 8D3 mAb was obtained by immunohistochemical screening for exclusive staining of vessels forming a blood-brain barrier (BBB), but not of other vessels. The anti-TfR mAb 8D3 recognizes the TfR also in FACS analysis and in western blots and should prove to be useful for affinity purification of the TfR. Whereas 8D3 brightly stains BBB-forming vessels in the central nervous system of mice, it does not stain the fenestrated capillaries within the choroid plexus and the circumventricular organs. In testis, where the blood-tissue barrier is located at the level of the Sertoli cells, the 8D3 mAb specifically stains Sertoli cells but not endothelial cells. Finally, in vitro, 8D3 does not interfere with iron uptake of lymphocytes as it does not influence their proliferation. Taken together, 8D3 represents a versatile new tool to study the tissue distribution of the murine TfR and TfR-mediated transcytosis across tissue barriers in the mouse.

Noncompetitive, chemokine-mediated inhibition of basic fibroblast growth factor-induced endothelial cell proliferation

The proinflammatory and chemoattractant chemokine interleukin-8 (IL-8) inhibits cell proliferation induced by basic fibroblast growth factor (bFGF) in mouse endothelial cells isolated from subcutaneous sponge implant (sponge-induced mouse endothelial cells) and in bovine aortic endothelial GM 7373 cells. The mechanism of action of IL-8 was investigated in GM 7373 cells. IL-8 did not prevent the binding of bFGF to its tyrosine kinase FGF receptors (FGFRs) nor to cell surface heparan sulfate proteoglycans (HSPGs). A transient interaction of IL-8 with the cell before the addition of the growth factor was sufficient to prevent bFGF activity. The inhibitory activity of IL-8 was abolished by protein kinase C (PKC) inhibitors and was mimicked by the PKC activator 12-O-tetradecanoylphorbol-13-acetate. Accordingly, both IL-8 and 12-O-tetradecanoylphorbol-13-acetate caused a approximately 60% decrease of the binding capacity of GM 7373 cells due to the down-regulation of FGFRs. Several C-X-C and C-C chemokines exerted an inhibitory action on bFGF activity similar to IL-8. Soluble heparin, 6-O-desulfated heparin, N-desulfated heparin, and heparan sulfate but not 2-O-desulfated heparin, chondroitin-4-sulfate, hyaluronic acid, and K5 polysaccharide abrogated IL-8 inhibitory activity consistently with the presence of low affinity, high capacity HSPG-like chemokine-binding sites on GM 7373 cells. Finally, neovascularization induced by bFGF in murine subcutaneous sponge implants was reduced significantly by IL-8. In conclusion, IL-8 inhibits the mitogenic activity exerted by bFGF on cultured endothelial cells by a PKC-dependent, noncompetitive mechanism of action that causes FGFR down-regulation. This activity is shared by several chemokines and requires endothelial cell surface HSPGs. The endothelial cell line utilized in the present study may help to elucidate the complex interplay among chemokines, HSPGs, growth factors, and receptors in endothelial cells.